Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

12 files changed, 8048 insertions, 0 deletions

diff --git a/vendor/object/src/write/coff/mod.rs b/vendor/object/src/write/coff/mod.rs
new file mode 100644
index 0000000..6e0f5ed
--- /dev/null
+++ b/vendor/object/src/write/coff/mod.rs
@@ -0,0 +1,10 @@
+//! Support for writing COFF files.
+//!
+//! Provides [`Writer`] for low level writing of COFF files.
+//! This is also used to provide COFF support for [`write::Object`](crate::write::Object).
+
+mod object;
+pub use self::object::*;
+
+mod writer;
+pub use writer::*;
diff --git a/vendor/object/src/write/coff/object.rs b/vendor/object/src/write/coff/object.rs
new file mode 100644
index 0000000..5229665
--- /dev/null
+++ b/vendor/object/src/write/coff/object.rs
@@ -0,0 +1,583 @@
+use alloc::vec::Vec;
+
+use crate::pe as coff;
+use crate::write::coff::writer;
+use crate::write::util::*;
+use crate::write::*;
+
+#[derive(Default, Clone, Copy)]
+struct SectionOffsets {
+    name: writer::Name,
+    offset: u32,
+    reloc_offset: u32,
+    selection: u8,
+    associative_section: u32,
+}
+
+#[derive(Default, Clone, Copy)]
+struct SymbolOffsets {
+    name: writer::Name,
+    index: u32,
+    aux_count: u8,
+}
+
+/// Internal format to use for the `.drectve` section containing linker
+/// directives for symbol exports.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum CoffExportStyle {
+    /// MSVC format supported by link.exe and LLD.
+    Msvc,
+    /// Gnu format supported by GNU LD and LLD.
+    Gnu,
+}
+
+impl<'a> Object<'a> {
+    pub(crate) fn coff_section_info(
+        &self,
+        section: StandardSection,
+    ) -> (&'static [u8], &'static [u8], SectionKind, SectionFlags) {
+        match section {
+            StandardSection::Text => (&[], &b".text"[..], SectionKind::Text, SectionFlags::None),
+            StandardSection::Data => (&[], &b".data"[..], SectionKind::Data, SectionFlags::None),
+            StandardSection::ReadOnlyData
+            | StandardSection::ReadOnlyDataWithRel
+            | StandardSection::ReadOnlyString => (
+                &[],
+                &b".rdata"[..],
+                SectionKind::ReadOnlyData,
+                SectionFlags::None,
+            ),
+            StandardSection::UninitializedData => (
+                &[],
+                &b".bss"[..],
+                SectionKind::UninitializedData,
+                SectionFlags::None,
+            ),
+            // TLS sections are data sections with a special name.
+            StandardSection::Tls => (&[], &b".tls$"[..], SectionKind::Data, SectionFlags::None),
+            StandardSection::UninitializedTls => {
+                // Unsupported section.
+                (&[], &[], SectionKind::UninitializedTls, SectionFlags::None)
+            }
+            StandardSection::TlsVariables => {
+                // Unsupported section.
+                (&[], &[], SectionKind::TlsVariables, SectionFlags::None)
+            }
+            StandardSection::Common => {
+                // Unsupported section.
+                (&[], &[], SectionKind::Common, SectionFlags::None)
+            }
+            StandardSection::GnuProperty => {
+                // Unsupported section.
+                (&[], &[], SectionKind::Note, SectionFlags::None)
+            }
+        }
+    }
+
+    pub(crate) fn coff_subsection_name(&self, section: &[u8], value: &[u8]) -> Vec<u8> {
+        let mut name = section.to_vec();
+        name.push(b'$');
+        name.extend_from_slice(value);
+        name
+    }
+
+    pub(crate) fn coff_fixup_relocation(&mut self, relocation: &mut Relocation) -> i64 {
+        if relocation.kind == RelocationKind::GotRelative {
+            // Use a stub symbol for the relocation instead.
+            // This isn't really a GOT, but it's a similar purpose.
+            // TODO: need to handle DLL imports differently?
+            relocation.kind = RelocationKind::Relative;
+            relocation.symbol = self.coff_add_stub_symbol(relocation.symbol);
+        } else if relocation.kind == RelocationKind::PltRelative {
+            // Windows doesn't need a separate relocation type for
+            // references to functions in import libraries.
+            // For convenience, treat this the same as Relative.
+            relocation.kind = RelocationKind::Relative;
+        }
+
+        let constant = match self.architecture {
+            Architecture::I386 | Architecture::Arm | Architecture::Aarch64 => match relocation.kind
+            {
+                RelocationKind::Relative => {
+                    // IMAGE_REL_I386_REL32, IMAGE_REL_ARM_REL32, IMAGE_REL_ARM64_REL32
+                    relocation.addend + 4
+                }
+                _ => relocation.addend,
+            },
+            Architecture::X86_64 => match relocation.kind {
+                RelocationKind::Relative => {
+                    // IMAGE_REL_AMD64_REL32 through to IMAGE_REL_AMD64_REL32_5
+                    if relocation.addend <= -4 && relocation.addend >= -9 {
+                        0
+                    } else {
+                        relocation.addend + 4
+                    }
+                }
+                _ => relocation.addend,
+            },
+            _ => unimplemented!(),
+        };
+        relocation.addend -= constant;
+        constant
+    }
+
+    fn coff_add_stub_symbol(&mut self, symbol_id: SymbolId) -> SymbolId {
+        if let Some(stub_id) = self.stub_symbols.get(&symbol_id) {
+            return *stub_id;
+        }
+        let stub_size = self.architecture.address_size().unwrap().bytes();
+
+        let name = b".rdata$.refptr".to_vec();
+        let section_id = self.add_section(Vec::new(), name, SectionKind::ReadOnlyData);
+        let section = self.section_mut(section_id);
+        section.set_data(vec![0; stub_size as usize], u64::from(stub_size));
+        section.relocations = vec![Relocation {
+            offset: 0,
+            size: stub_size * 8,
+            kind: RelocationKind::Absolute,
+            encoding: RelocationEncoding::Generic,
+            symbol: symbol_id,
+            addend: 0,
+        }];
+
+        let mut name = b".refptr.".to_vec();
+        name.extend_from_slice(&self.symbol(symbol_id).name);
+        let stub_id = self.add_raw_symbol(Symbol {
+            name,
+            value: 0,
+            size: u64::from(stub_size),
+            kind: SymbolKind::Data,
+            scope: SymbolScope::Compilation,
+            weak: false,
+            section: SymbolSection::Section(section_id),
+            flags: SymbolFlags::None,
+        });
+        self.stub_symbols.insert(symbol_id, stub_id);
+
+        stub_id
+    }
+
+    /// Appends linker directives to the `.drectve` section to tell the linker
+    /// to export all symbols with `SymbolScope::Dynamic`.
+    ///
+    /// This must be called after all symbols have been defined.
+    pub fn add_coff_exports(&mut self, style: CoffExportStyle) {
+        assert_eq!(self.format, BinaryFormat::Coff);
+
+        let mut directives = vec![];
+        for symbol in &self.symbols {
+            if symbol.scope == SymbolScope::Dynamic {
+                match style {
+                    CoffExportStyle::Msvc => directives.extend(b" /EXPORT:\""),
+                    CoffExportStyle::Gnu => directives.extend(b" -export:\""),
+                }
+                directives.extend(&symbol.name);
+                directives.extend(b"\"");
+                if symbol.kind != SymbolKind::Text {
+                    match style {
+                        CoffExportStyle::Msvc => directives.extend(b",DATA"),
+                        CoffExportStyle::Gnu => directives.extend(b",data"),
+                    }
+                }
+            }
+        }
+        let drectve = self.add_section(vec![], b".drectve".to_vec(), SectionKind::Linker);
+        self.append_section_data(drectve, &directives, 1);
+    }
+
+    pub(crate) fn coff_write(&self, buffer: &mut dyn WritableBuffer) -> Result<()> {
+        let mut writer = writer::Writer::new(buffer);
+
+        // Add section strings to strtab.
+        let mut section_offsets = vec![SectionOffsets::default(); self.sections.len()];
+        for (index, section) in self.sections.iter().enumerate() {
+            section_offsets[index].name = writer.add_name(&section.name);
+        }
+
+        // Set COMDAT flags.
+        for comdat in &self.comdats {
+            let symbol = &self.symbols[comdat.symbol.0];
+            let comdat_section = match symbol.section {
+                SymbolSection::Section(id) => id.0,
+                _ => {
+                    return Err(Error(format!(
+                        "unsupported COMDAT symbol `{}` section {:?}",
+                        symbol.name().unwrap_or(""),
+                        symbol.section
+                    )));
+                }
+            };
+            section_offsets[comdat_section].selection = match comdat.kind {
+                ComdatKind::NoDuplicates => coff::IMAGE_COMDAT_SELECT_NODUPLICATES,
+                ComdatKind::Any => coff::IMAGE_COMDAT_SELECT_ANY,
+                ComdatKind::SameSize => coff::IMAGE_COMDAT_SELECT_SAME_SIZE,
+                ComdatKind::ExactMatch => coff::IMAGE_COMDAT_SELECT_EXACT_MATCH,
+                ComdatKind::Largest => coff::IMAGE_COMDAT_SELECT_LARGEST,
+                ComdatKind::Newest => coff::IMAGE_COMDAT_SELECT_NEWEST,
+                ComdatKind::Unknown => {
+                    return Err(Error(format!(
+                        "unsupported COMDAT symbol `{}` kind {:?}",
+                        symbol.name().unwrap_or(""),
+                        comdat.kind
+                    )));
+                }
+            };
+            for id in &comdat.sections {
+                let section = &self.sections[id.0];
+                if section.symbol.is_none() {
+                    return Err(Error(format!(
+                        "missing symbol for COMDAT section `{}`",
+                        section.name().unwrap_or(""),
+                    )));
+                }
+                if id.0 != comdat_section {
+                    section_offsets[id.0].selection = coff::IMAGE_COMDAT_SELECT_ASSOCIATIVE;
+                    section_offsets[id.0].associative_section = comdat_section as u32 + 1;
+                }
+            }
+        }
+
+        // Reserve symbol indices and add symbol strings to strtab.
+        let mut symbol_offsets = vec![SymbolOffsets::default(); self.symbols.len()];
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            symbol_offsets[index].index = writer.reserve_symbol_index();
+            let mut name = &*symbol.name;
+            match symbol.kind {
+                SymbolKind::File => {
+                    // Name goes in auxiliary symbol records.
+                    symbol_offsets[index].aux_count = writer.reserve_aux_file_name(&symbol.name);
+                    name = b".file";
+                }
+                SymbolKind::Section if symbol.section.id().is_some() => {
+                    symbol_offsets[index].aux_count = writer.reserve_aux_section();
+                }
+                _ => {}
+            };
+            symbol_offsets[index].name = writer.add_name(name);
+        }
+
+        // Reserve file ranges.
+        writer.reserve_file_header();
+        writer.reserve_section_headers(self.sections.len() as u16);
+        for (index, section) in self.sections.iter().enumerate() {
+            section_offsets[index].offset = writer.reserve_section(section.data.len());
+            section_offsets[index].reloc_offset =
+                writer.reserve_relocations(section.relocations.len());
+        }
+        writer.reserve_symtab_strtab();
+
+        // Start writing.
+        writer.write_file_header(writer::FileHeader {
+            machine: match (self.architecture, self.sub_architecture) {
+                (Architecture::Arm, None) => coff::IMAGE_FILE_MACHINE_ARMNT,
+                (Architecture::Aarch64, None) => coff::IMAGE_FILE_MACHINE_ARM64,
+                (Architecture::Aarch64, Some(SubArchitecture::Arm64EC)) => {
+                    coff::IMAGE_FILE_MACHINE_ARM64EC
+                }
+                (Architecture::I386, None) => coff::IMAGE_FILE_MACHINE_I386,
+                (Architecture::X86_64, None) => coff::IMAGE_FILE_MACHINE_AMD64,
+                _ => {
+                    return Err(Error(format!(
+                        "unimplemented architecture {:?} with sub-architecture {:?}",
+                        self.architecture, self.sub_architecture
+                    )));
+                }
+            },
+            time_date_stamp: 0,
+            characteristics: match self.flags {
+                FileFlags::Coff { characteristics } => characteristics,
+                _ => 0,
+            },
+        })?;
+
+        // Write section headers.
+        for (index, section) in self.sections.iter().enumerate() {
+            let mut characteristics = if let SectionFlags::Coff {
+                characteristics, ..
+            } = section.flags
+            {
+                characteristics
+            } else {
+                match section.kind {
+                    SectionKind::Text => {
+                        coff::IMAGE_SCN_CNT_CODE
+                            | coff::IMAGE_SCN_MEM_EXECUTE
+                            | coff::IMAGE_SCN_MEM_READ
+                    }
+                    SectionKind::Data => {
+                        coff::IMAGE_SCN_CNT_INITIALIZED_DATA
+                            | coff::IMAGE_SCN_MEM_READ
+                            | coff::IMAGE_SCN_MEM_WRITE
+                    }
+                    SectionKind::UninitializedData => {
+                        coff::IMAGE_SCN_CNT_UNINITIALIZED_DATA
+                            | coff::IMAGE_SCN_MEM_READ
+                            | coff::IMAGE_SCN_MEM_WRITE
+                    }
+                    SectionKind::ReadOnlyData
+                    | SectionKind::ReadOnlyDataWithRel
+                    | SectionKind::ReadOnlyString => {
+                        coff::IMAGE_SCN_CNT_INITIALIZED_DATA | coff::IMAGE_SCN_MEM_READ
+                    }
+                    SectionKind::Debug | SectionKind::Other | SectionKind::OtherString => {
+                        coff::IMAGE_SCN_CNT_INITIALIZED_DATA
+                            | coff::IMAGE_SCN_MEM_READ
+                            | coff::IMAGE_SCN_MEM_DISCARDABLE
+                    }
+                    SectionKind::Linker => coff::IMAGE_SCN_LNK_INFO | coff::IMAGE_SCN_LNK_REMOVE,
+                    SectionKind::Common
+                    | SectionKind::Tls
+                    | SectionKind::UninitializedTls
+                    | SectionKind::TlsVariables
+                    | SectionKind::Note
+                    | SectionKind::Unknown
+                    | SectionKind::Metadata
+                    | SectionKind::Elf(_) => {
+                        return Err(Error(format!(
+                            "unimplemented section `{}` kind {:?}",
+                            section.name().unwrap_or(""),
+                            section.kind
+                        )));
+                    }
+                }
+            };
+            if section_offsets[index].selection != 0 {
+                characteristics |= coff::IMAGE_SCN_LNK_COMDAT;
+            };
+            if section.relocations.len() > 0xffff {
+                characteristics |= coff::IMAGE_SCN_LNK_NRELOC_OVFL;
+            }
+            characteristics |= match section.align {
+                1 => coff::IMAGE_SCN_ALIGN_1BYTES,
+                2 => coff::IMAGE_SCN_ALIGN_2BYTES,
+                4 => coff::IMAGE_SCN_ALIGN_4BYTES,
+                8 => coff::IMAGE_SCN_ALIGN_8BYTES,
+                16 => coff::IMAGE_SCN_ALIGN_16BYTES,
+                32 => coff::IMAGE_SCN_ALIGN_32BYTES,
+                64 => coff::IMAGE_SCN_ALIGN_64BYTES,
+                128 => coff::IMAGE_SCN_ALIGN_128BYTES,
+                256 => coff::IMAGE_SCN_ALIGN_256BYTES,
+                512 => coff::IMAGE_SCN_ALIGN_512BYTES,
+                1024 => coff::IMAGE_SCN_ALIGN_1024BYTES,
+                2048 => coff::IMAGE_SCN_ALIGN_2048BYTES,
+                4096 => coff::IMAGE_SCN_ALIGN_4096BYTES,
+                8192 => coff::IMAGE_SCN_ALIGN_8192BYTES,
+                _ => {
+                    return Err(Error(format!(
+                        "unimplemented section `{}` align {}",
+                        section.name().unwrap_or(""),
+                        section.align
+                    )));
+                }
+            };
+            writer.write_section_header(writer::SectionHeader {
+                name: section_offsets[index].name,
+                size_of_raw_data: section.size as u32,
+                pointer_to_raw_data: section_offsets[index].offset,
+                pointer_to_relocations: section_offsets[index].reloc_offset,
+                pointer_to_linenumbers: 0,
+                number_of_relocations: section.relocations.len() as u32,
+                number_of_linenumbers: 0,
+                characteristics,
+            });
+        }
+
+        // Write section data and relocations.
+        for section in &self.sections {
+            writer.write_section(&section.data);
+
+            if !section.relocations.is_empty() {
+                //debug_assert_eq!(section_offsets[index].reloc_offset, buffer.len());
+                writer.write_relocations_count(section.relocations.len());
+                for reloc in &section.relocations {
+                    //assert!(reloc.implicit_addend);
+                    let typ = match self.architecture {
+                        Architecture::I386 => match (reloc.kind, reloc.size, reloc.addend) {
+                            (RelocationKind::Absolute, 16, 0) => coff::IMAGE_REL_I386_DIR16,
+                            (RelocationKind::Relative, 16, 0) => coff::IMAGE_REL_I386_REL16,
+                            (RelocationKind::Absolute, 32, 0) => coff::IMAGE_REL_I386_DIR32,
+                            (RelocationKind::ImageOffset, 32, 0) => coff::IMAGE_REL_I386_DIR32NB,
+                            (RelocationKind::SectionIndex, 16, 0) => coff::IMAGE_REL_I386_SECTION,
+                            (RelocationKind::SectionOffset, 32, 0) => coff::IMAGE_REL_I386_SECREL,
+                            (RelocationKind::SectionOffset, 7, 0) => coff::IMAGE_REL_I386_SECREL7,
+                            (RelocationKind::Relative, 32, -4) => coff::IMAGE_REL_I386_REL32,
+                            (RelocationKind::Coff(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::X86_64 => match (reloc.kind, reloc.size, reloc.addend) {
+                            (RelocationKind::Absolute, 64, 0) => coff::IMAGE_REL_AMD64_ADDR64,
+                            (RelocationKind::Absolute, 32, 0) => coff::IMAGE_REL_AMD64_ADDR32,
+                            (RelocationKind::ImageOffset, 32, 0) => coff::IMAGE_REL_AMD64_ADDR32NB,
+                            (RelocationKind::Relative, 32, -4) => coff::IMAGE_REL_AMD64_REL32,
+                            (RelocationKind::Relative, 32, -5) => coff::IMAGE_REL_AMD64_REL32_1,
+                            (RelocationKind::Relative, 32, -6) => coff::IMAGE_REL_AMD64_REL32_2,
+                            (RelocationKind::Relative, 32, -7) => coff::IMAGE_REL_AMD64_REL32_3,
+                            (RelocationKind::Relative, 32, -8) => coff::IMAGE_REL_AMD64_REL32_4,
+                            (RelocationKind::Relative, 32, -9) => coff::IMAGE_REL_AMD64_REL32_5,
+                            (RelocationKind::SectionIndex, 16, 0) => coff::IMAGE_REL_AMD64_SECTION,
+                            (RelocationKind::SectionOffset, 32, 0) => coff::IMAGE_REL_AMD64_SECREL,
+                            (RelocationKind::SectionOffset, 7, 0) => coff::IMAGE_REL_AMD64_SECREL7,
+                            (RelocationKind::Coff(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Arm => match (reloc.kind, reloc.size, reloc.addend) {
+                            (RelocationKind::Absolute, 32, 0) => coff::IMAGE_REL_ARM_ADDR32,
+                            (RelocationKind::ImageOffset, 32, 0) => coff::IMAGE_REL_ARM_ADDR32NB,
+                            (RelocationKind::Relative, 32, -4) => coff::IMAGE_REL_ARM_REL32,
+                            (RelocationKind::SectionIndex, 16, 0) => coff::IMAGE_REL_ARM_SECTION,
+                            (RelocationKind::SectionOffset, 32, 0) => coff::IMAGE_REL_ARM_SECREL,
+                            (RelocationKind::Coff(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Aarch64 => match (reloc.kind, reloc.size, reloc.addend) {
+                            (RelocationKind::Absolute, 32, 0) => coff::IMAGE_REL_ARM64_ADDR32,
+                            (RelocationKind::ImageOffset, 32, 0) => coff::IMAGE_REL_ARM64_ADDR32NB,
+                            (RelocationKind::SectionIndex, 16, 0) => coff::IMAGE_REL_ARM64_SECTION,
+                            (RelocationKind::SectionOffset, 32, 0) => coff::IMAGE_REL_ARM64_SECREL,
+                            (RelocationKind::Absolute, 64, 0) => coff::IMAGE_REL_ARM64_ADDR64,
+                            (RelocationKind::Relative, 32, -4) => coff::IMAGE_REL_ARM64_REL32,
+                            (RelocationKind::Coff(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        _ => {
+                            return Err(Error(format!(
+                                "unimplemented architecture {:?}",
+                                self.architecture
+                            )));
+                        }
+                    };
+                    writer.write_relocation(writer::Relocation {
+                        virtual_address: reloc.offset as u32,
+                        symbol: symbol_offsets[reloc.symbol.0].index,
+                        typ,
+                    });
+                }
+            }
+        }
+
+        // Write symbols.
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            let section_number = match symbol.section {
+                SymbolSection::None => {
+                    debug_assert_eq!(symbol.kind, SymbolKind::File);
+                    coff::IMAGE_SYM_DEBUG as u16
+                }
+                SymbolSection::Undefined => coff::IMAGE_SYM_UNDEFINED as u16,
+                SymbolSection::Absolute => coff::IMAGE_SYM_ABSOLUTE as u16,
+                SymbolSection::Common => coff::IMAGE_SYM_UNDEFINED as u16,
+                SymbolSection::Section(id) => id.0 as u16 + 1,
+            };
+            let typ = if symbol.kind == SymbolKind::Text {
+                coff::IMAGE_SYM_DTYPE_FUNCTION << coff::IMAGE_SYM_DTYPE_SHIFT
+            } else {
+                coff::IMAGE_SYM_TYPE_NULL
+            };
+            let storage_class = match symbol.kind {
+                SymbolKind::File => coff::IMAGE_SYM_CLASS_FILE,
+                SymbolKind::Section => {
+                    if symbol.section.id().is_some() {
+                        coff::IMAGE_SYM_CLASS_STATIC
+                    } else {
+                        coff::IMAGE_SYM_CLASS_SECTION
+                    }
+                }
+                SymbolKind::Label => coff::IMAGE_SYM_CLASS_LABEL,
+                SymbolKind::Text | SymbolKind::Data | SymbolKind::Tls => {
+                    match symbol.section {
+                        SymbolSection::None => {
+                            return Err(Error(format!(
+                                "missing section for symbol `{}`",
+                                symbol.name().unwrap_or("")
+                            )));
+                        }
+                        SymbolSection::Undefined | SymbolSection::Common => {
+                            coff::IMAGE_SYM_CLASS_EXTERNAL
+                        }
+                        SymbolSection::Absolute | SymbolSection::Section(_) => {
+                            match symbol.scope {
+                                // TODO: does this need aux symbol records too?
+                                _ if symbol.weak => coff::IMAGE_SYM_CLASS_WEAK_EXTERNAL,
+                                SymbolScope::Unknown => {
+                                    return Err(Error(format!(
+                                        "unimplemented symbol `{}` scope {:?}",
+                                        symbol.name().unwrap_or(""),
+                                        symbol.scope
+                                    )));
+                                }
+                                SymbolScope::Compilation => coff::IMAGE_SYM_CLASS_STATIC,
+                                SymbolScope::Linkage | SymbolScope::Dynamic => {
+                                    coff::IMAGE_SYM_CLASS_EXTERNAL
+                                }
+                            }
+                        }
+                    }
+                }
+                SymbolKind::Unknown | SymbolKind::Null => {
+                    return Err(Error(format!(
+                        "unimplemented symbol `{}` kind {:?}",
+                        symbol.name().unwrap_or(""),
+                        symbol.kind
+                    )));
+                }
+            };
+            let number_of_aux_symbols = symbol_offsets[index].aux_count;
+            let value = if symbol.section == SymbolSection::Common {
+                symbol.size as u32
+            } else {
+                symbol.value as u32
+            };
+            writer.write_symbol(writer::Symbol {
+                name: symbol_offsets[index].name,
+                value,
+                section_number,
+                typ,
+                storage_class,
+                number_of_aux_symbols,
+            });
+
+            // Write auxiliary symbols.
+            match symbol.kind {
+                SymbolKind::File => {
+                    writer.write_aux_file_name(&symbol.name, number_of_aux_symbols);
+                }
+                SymbolKind::Section if symbol.section.id().is_some() => {
+                    debug_assert_eq!(number_of_aux_symbols, 1);
+                    let section_index = symbol.section.id().unwrap().0;
+                    let section = &self.sections[section_index];
+                    writer.write_aux_section(writer::AuxSymbolSection {
+                        length: section.size as u32,
+                        number_of_relocations: section.relocations.len() as u32,
+                        number_of_linenumbers: 0,
+                        check_sum: checksum(section.data()),
+                        number: section_offsets[section_index].associative_section,
+                        selection: section_offsets[section_index].selection,
+                    });
+                }
+                _ => {
+                    debug_assert_eq!(number_of_aux_symbols, 0);
+                }
+            }
+        }
+
+        writer.write_strtab();
+
+        debug_assert_eq!(writer.reserved_len(), writer.len());
+
+        Ok(())
+    }
+}
+
+// JamCRC
+fn checksum(data: &[u8]) -> u32 {
+    let mut hasher = crc32fast::Hasher::new_with_initial(0xffff_ffff);
+    hasher.update(data);
+    !hasher.finalize()
+}
diff --git a/vendor/object/src/write/coff/writer.rs b/vendor/object/src/write/coff/writer.rs
new file mode 100644
index 0000000..8c7ada3
--- /dev/null
+++ b/vendor/object/src/write/coff/writer.rs
@@ -0,0 +1,518 @@
+//! Helper for writing COFF files.
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::mem;
+
+use crate::endian::{LittleEndian as LE, U16Bytes, U32Bytes, U16, U32};
+use crate::pe;
+use crate::write::string::{StringId, StringTable};
+use crate::write::util;
+use crate::write::{Error, Result, WritableBuffer};
+
+/// A helper for writing COFF files.
+///
+/// Writing uses a two phase approach. The first phase builds up all of the information
+/// that may need to be known ahead of time:
+/// - build string table
+/// - reserve section indices
+/// - reserve symbol indices
+/// - reserve file ranges for headers and sections
+///
+/// Some of the information has ordering requirements. For example, strings must be added
+/// to the string table before reserving the file range for the string table. There are debug
+/// asserts to check some of these requirements.
+///
+/// The second phase writes everything out in order. Thus the caller must ensure writing
+/// is in the same order that file ranges were reserved. There are debug asserts to assist
+/// with checking this.
+#[allow(missing_debug_implementations)]
+pub struct Writer<'a> {
+    buffer: &'a mut dyn WritableBuffer,
+    len: usize,
+
+    section_num: u16,
+
+    symtab_offset: u32,
+    symtab_num: u32,
+
+    strtab: StringTable<'a>,
+    strtab_len: usize,
+    strtab_offset: u32,
+    strtab_data: Vec<u8>,
+}
+
+impl<'a> Writer<'a> {
+    /// Create a new `Writer`.
+    pub fn new(buffer: &'a mut dyn WritableBuffer) -> Self {
+        Writer {
+            buffer,
+            len: 0,
+
+            section_num: 0,
+
+            symtab_offset: 0,
+            symtab_num: 0,
+
+            strtab: StringTable::default(),
+            strtab_len: 0,
+            strtab_offset: 0,
+            strtab_data: Vec::new(),
+        }
+    }
+
+    /// Return the current file length that has been reserved.
+    pub fn reserved_len(&self) -> usize {
+        self.len
+    }
+
+    /// Return the current file length that has been written.
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> usize {
+        self.buffer.len()
+    }
+
+    /// Reserve a file range with the given size and starting alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve(&mut self, len: usize, align_start: usize) -> u32 {
+        if align_start > 1 {
+            self.len = util::align(self.len, align_start);
+        }
+        let offset = self.len;
+        self.len += len;
+        offset as u32
+    }
+
+    /// Write alignment padding bytes.
+    pub fn write_align(&mut self, align_start: usize) {
+        if align_start > 1 {
+            util::write_align(self.buffer, align_start);
+        }
+    }
+
+    /// Write data.
+    pub fn write(&mut self, data: &[u8]) {
+        self.buffer.write_bytes(data);
+    }
+
+    /// Reserve the file range up to the given file offset.
+    pub fn reserve_until(&mut self, offset: usize) {
+        debug_assert!(self.len <= offset);
+        self.len = offset;
+    }
+
+    /// Write padding up to the given file offset.
+    pub fn pad_until(&mut self, offset: usize) {
+        debug_assert!(self.buffer.len() <= offset);
+        self.buffer.resize(offset);
+    }
+
+    /// Reserve the range for the file header.
+    ///
+    /// This must be at the start of the file.
+    pub fn reserve_file_header(&mut self) {
+        debug_assert_eq!(self.len, 0);
+        self.reserve(mem::size_of::<pe::ImageFileHeader>(), 1);
+    }
+
+    /// Write the file header.
+    ///
+    /// This must be at the start of the file.
+    ///
+    /// Fields that can be derived from known information are automatically set by this function.
+    pub fn write_file_header(&mut self, header: FileHeader) -> Result<()> {
+        debug_assert_eq!(self.buffer.len(), 0);
+
+        // Start writing.
+        self.buffer
+            .reserve(self.len)
+            .map_err(|_| Error(String::from("Cannot allocate buffer")))?;
+
+        // Write file header.
+        let header = pe::ImageFileHeader {
+            machine: U16::new(LE, header.machine),
+            number_of_sections: U16::new(LE, self.section_num),
+            time_date_stamp: U32::new(LE, header.time_date_stamp),
+            pointer_to_symbol_table: U32::new(LE, self.symtab_offset),
+            number_of_symbols: U32::new(LE, self.symtab_num),
+            size_of_optional_header: U16::default(),
+            characteristics: U16::new(LE, header.characteristics),
+        };
+        self.buffer.write(&header);
+
+        Ok(())
+    }
+
+    /// Reserve the range for the section headers.
+    pub fn reserve_section_headers(&mut self, section_num: u16) {
+        debug_assert_eq!(self.section_num, 0);
+        self.section_num = section_num;
+        self.reserve(
+            section_num as usize * mem::size_of::<pe::ImageSectionHeader>(),
+            1,
+        );
+    }
+
+    /// Write a section header.
+    pub fn write_section_header(&mut self, section: SectionHeader) {
+        let mut coff_section = pe::ImageSectionHeader {
+            name: [0; 8],
+            virtual_size: U32::default(),
+            virtual_address: U32::default(),
+            size_of_raw_data: U32::new(LE, section.size_of_raw_data),
+            pointer_to_raw_data: U32::new(LE, section.pointer_to_raw_data),
+            pointer_to_relocations: U32::new(LE, section.pointer_to_relocations),
+            pointer_to_linenumbers: U32::new(LE, section.pointer_to_linenumbers),
+            number_of_relocations: if section.number_of_relocations > 0xffff {
+                U16::new(LE, 0xffff)
+            } else {
+                U16::new(LE, section.number_of_relocations as u16)
+            },
+            number_of_linenumbers: U16::default(),
+            characteristics: U32::new(LE, section.characteristics),
+        };
+        match section.name {
+            Name::Short(name) => coff_section.name = name,
+            Name::Long(str_id) => {
+                let mut str_offset = self.strtab.get_offset(str_id);
+                if str_offset <= 9_999_999 {
+                    let mut name = [0; 7];
+                    let mut len = 0;
+                    if str_offset == 0 {
+                        name[6] = b'0';
+                        len = 1;
+                    } else {
+                        while str_offset != 0 {
+                            let rem = (str_offset % 10) as u8;
+                            str_offset /= 10;
+                            name[6 - len] = b'0' + rem;
+                            len += 1;
+                        }
+                    }
+                    coff_section.name = [0; 8];
+                    coff_section.name[0] = b'/';
+                    coff_section.name[1..][..len].copy_from_slice(&name[7 - len..]);
+                } else {
+                    debug_assert!(str_offset as u64 <= 0xf_ffff_ffff);
+                    coff_section.name[0] = b'/';
+                    coff_section.name[1] = b'/';
+                    for i in 0..6 {
+                        let rem = (str_offset % 64) as u8;
+                        str_offset /= 64;
+                        let c = match rem {
+                            0..=25 => b'A' + rem,
+                            26..=51 => b'a' + rem - 26,
+                            52..=61 => b'0' + rem - 52,
+                            62 => b'+',
+                            63 => b'/',
+                            _ => unreachable!(),
+                        };
+                        coff_section.name[7 - i] = c;
+                    }
+                }
+            }
+        }
+        self.buffer.write(&coff_section);
+    }
+
+    /// Reserve the range for the section data.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    /// Does nothing and returns 0 if the length is zero.
+    pub fn reserve_section(&mut self, len: usize) -> u32 {
+        if len == 0 {
+            return 0;
+        }
+        // TODO: not sure what alignment is required here, but this seems to match LLVM
+        self.reserve(len, 4)
+    }
+
+    /// Write the alignment bytes prior to section data.
+    ///
+    /// This is unneeded if you are using `write_section` or `write_section_zeroes`
+    /// for the data.
+    pub fn write_section_align(&mut self) {
+        util::write_align(self.buffer, 4);
+    }
+
+    /// Write the section data.
+    ///
+    /// Writes alignment bytes prior to the data.
+    /// Does nothing if the data is empty.
+    pub fn write_section(&mut self, data: &[u8]) {
+        if data.is_empty() {
+            return;
+        }
+        self.write_section_align();
+        self.buffer.write_bytes(data);
+    }
+
+    /// Write the section data using zero bytes.
+    ///
+    /// Writes alignment bytes prior to the data.
+    /// Does nothing if the length is zero.
+    pub fn write_section_zeroes(&mut self, len: usize) {
+        if len == 0 {
+            return;
+        }
+        self.write_section_align();
+        self.buffer.resize(self.buffer.len() + len);
+    }
+
+    /// Reserve a file range for the given number of relocations.
+    ///
+    /// This will automatically reserve an extra relocation if there are more than 0xffff.
+    ///
+    /// Returns the offset of the range.
+    /// Does nothing and returns 0 if the count is zero.
+    pub fn reserve_relocations(&mut self, mut count: usize) -> u32 {
+        if count == 0 {
+            return 0;
+        }
+        if count > 0xffff {
+            count += 1;
+        }
+        self.reserve(count * mem::size_of::<pe::ImageRelocation>(), 1)
+    }
+
+    /// Write a relocation containing the count if required.
+    ///
+    /// This should be called before writing the first relocation for a section.
+    pub fn write_relocations_count(&mut self, count: usize) {
+        if count > 0xffff {
+            let coff_relocation = pe::ImageRelocation {
+                virtual_address: U32Bytes::new(LE, count as u32 + 1),
+                symbol_table_index: U32Bytes::new(LE, 0),
+                typ: U16Bytes::new(LE, 0),
+            };
+            self.buffer.write(&coff_relocation);
+        }
+    }
+
+    /// Write a relocation.
+    pub fn write_relocation(&mut self, reloc: Relocation) {
+        let coff_relocation = pe::ImageRelocation {
+            virtual_address: U32Bytes::new(LE, reloc.virtual_address),
+            symbol_table_index: U32Bytes::new(LE, reloc.symbol),
+            typ: U16Bytes::new(LE, reloc.typ),
+        };
+        self.buffer.write(&coff_relocation);
+    }
+
+    /// Reserve a symbol table entry.
+    ///
+    /// This must be called before [`Self::reserve_symtab_strtab`].
+    pub fn reserve_symbol_index(&mut self) -> u32 {
+        debug_assert_eq!(self.symtab_offset, 0);
+        let index = self.symtab_num;
+        self.symtab_num += 1;
+        index
+    }
+
+    /// Reserve a number of symbol table entries.
+    pub fn reserve_symbol_indices(&mut self, count: u32) {
+        debug_assert_eq!(self.symtab_offset, 0);
+        self.symtab_num += count;
+    }
+
+    /// Write a symbol table entry.
+    pub fn write_symbol(&mut self, symbol: Symbol) {
+        let mut coff_symbol = pe::ImageSymbol {
+            name: [0; 8],
+            value: U32Bytes::new(LE, symbol.value),
+            section_number: U16Bytes::new(LE, symbol.section_number),
+            typ: U16Bytes::new(LE, symbol.typ),
+            storage_class: symbol.storage_class,
+            number_of_aux_symbols: symbol.number_of_aux_symbols,
+        };
+        match symbol.name {
+            Name::Short(name) => coff_symbol.name = name,
+            Name::Long(str_id) => {
+                let str_offset = self.strtab.get_offset(str_id);
+                coff_symbol.name[4..8].copy_from_slice(&u32::to_le_bytes(str_offset as u32));
+            }
+        }
+        self.buffer.write(&coff_symbol);
+    }
+
+    /// Reserve auxiliary symbols for a file name.
+    ///
+    /// Returns the number of auxiliary symbols required.
+    ///
+    /// This must be called before [`Self::reserve_symtab_strtab`].
+    pub fn reserve_aux_file_name(&mut self, name: &[u8]) -> u8 {
+        debug_assert_eq!(self.symtab_offset, 0);
+        let aux_count = (name.len() + pe::IMAGE_SIZEOF_SYMBOL - 1) / pe::IMAGE_SIZEOF_SYMBOL;
+        self.symtab_num += aux_count as u32;
+        aux_count as u8
+    }
+
+    /// Write auxiliary symbols for a file name.
+    pub fn write_aux_file_name(&mut self, name: &[u8], aux_count: u8) {
+        let aux_len = aux_count as usize * pe::IMAGE_SIZEOF_SYMBOL;
+        debug_assert!(aux_len >= name.len());
+        let old_len = self.buffer.len();
+        self.buffer.write_bytes(name);
+        self.buffer.resize(old_len + aux_len);
+    }
+
+    /// Reserve an auxiliary symbol for a section.
+    ///
+    /// Returns the number of auxiliary symbols required.
+    ///
+    /// This must be called before [`Self::reserve_symtab_strtab`].
+    pub fn reserve_aux_section(&mut self) -> u8 {
+        debug_assert_eq!(self.symtab_offset, 0);
+        self.symtab_num += 1;
+        1
+    }
+
+    /// Write an auxiliary symbol for a section.
+    pub fn write_aux_section(&mut self, section: AuxSymbolSection) {
+        let aux = pe::ImageAuxSymbolSection {
+            length: U32Bytes::new(LE, section.length),
+            number_of_relocations: if section.number_of_relocations > 0xffff {
+                U16Bytes::new(LE, 0xffff)
+            } else {
+                U16Bytes::new(LE, section.number_of_relocations as u16)
+            },
+            number_of_linenumbers: U16Bytes::new(LE, section.number_of_linenumbers),
+            check_sum: U32Bytes::new(LE, section.check_sum),
+            number: U16Bytes::new(LE, section.number as u16),
+            selection: section.selection,
+            reserved: 0,
+            high_number: U16Bytes::new(LE, (section.number >> 16) as u16),
+        };
+        self.buffer.write(&aux);
+    }
+
+    /// Return the number of reserved symbol table entries.
+    pub fn symbol_count(&self) -> u32 {
+        self.symtab_num
+    }
+
+    /// Add a string to the string table.
+    ///
+    /// This must be called before [`Self::reserve_symtab_strtab`].
+    pub fn add_string(&mut self, name: &'a [u8]) -> StringId {
+        debug_assert_eq!(self.strtab_offset, 0);
+        self.strtab.add(name)
+    }
+
+    /// Add a section or symbol name to the string table if required.
+    ///
+    /// This must be called before [`Self::reserve_symtab_strtab`].
+    pub fn add_name(&mut self, name: &'a [u8]) -> Name {
+        if name.len() > 8 {
+            Name::Long(self.add_string(name))
+        } else {
+            let mut short_name = [0; 8];
+            short_name[..name.len()].copy_from_slice(name);
+            Name::Short(short_name)
+        }
+    }
+
+    /// Reserve the range for the symbol table and string table.
+    ///
+    /// This must be called after functions that reserve symbol
+    /// indices or add strings.
+    pub fn reserve_symtab_strtab(&mut self) {
+        debug_assert_eq!(self.symtab_offset, 0);
+        self.symtab_offset = self.reserve(self.symtab_num as usize * pe::IMAGE_SIZEOF_SYMBOL, 1);
+
+        debug_assert_eq!(self.strtab_offset, 0);
+        // First 4 bytes of strtab are the length.
+        self.strtab.write(4, &mut self.strtab_data);
+        self.strtab_len = self.strtab_data.len() + 4;
+        self.strtab_offset = self.reserve(self.strtab_len, 1);
+    }
+
+    /// Write the string table.
+    pub fn write_strtab(&mut self) {
+        debug_assert_eq!(self.strtab_offset, self.buffer.len() as u32);
+        self.buffer
+            .write_bytes(&u32::to_le_bytes(self.strtab_len as u32));
+        self.buffer.write_bytes(&self.strtab_data);
+    }
+}
+
+/// Shortened and native endian version of [`pe::ImageFileHeader`].
+#[allow(missing_docs)]
+#[derive(Debug, Default, Clone)]
+pub struct FileHeader {
+    pub machine: u16,
+    pub time_date_stamp: u32,
+    pub characteristics: u16,
+}
+
+/// A section or symbol name.
+#[derive(Debug, Clone, Copy)]
+pub enum Name {
+    /// An inline name.
+    Short([u8; 8]),
+    /// An id of a string table entry.
+    Long(StringId),
+}
+
+impl Default for Name {
+    fn default() -> Name {
+        Name::Short([0; 8])
+    }
+}
+
+// From isn't useful.
+#[allow(clippy::from_over_into)]
+impl<'a> Into<Name> for &'a [u8; 8] {
+    fn into(self) -> Name {
+        Name::Short(*self)
+    }
+}
+
+/// Native endian version of [`pe::ImageSectionHeader`].
+#[allow(missing_docs)]
+#[derive(Debug, Default, Clone)]
+pub struct SectionHeader {
+    pub name: Name,
+    pub size_of_raw_data: u32,
+    pub pointer_to_raw_data: u32,
+    pub pointer_to_relocations: u32,
+    pub pointer_to_linenumbers: u32,
+    /// This will automatically be clamped if there are more than 0xffff.
+    pub number_of_relocations: u32,
+    pub number_of_linenumbers: u16,
+    pub characteristics: u32,
+}
+
+/// Native endian version of [`pe::ImageSymbol`].
+#[allow(missing_docs)]
+#[derive(Debug, Default, Clone)]
+pub struct Symbol {
+    pub name: Name,
+    pub value: u32,
+    pub section_number: u16,
+    pub typ: u16,
+    pub storage_class: u8,
+    pub number_of_aux_symbols: u8,
+}
+
+/// Native endian version of [`pe::ImageAuxSymbolSection`].
+#[allow(missing_docs)]
+#[derive(Debug, Default, Clone)]
+pub struct AuxSymbolSection {
+    pub length: u32,
+    /// This will automatically be clamped if there are more than 0xffff.
+    pub number_of_relocations: u32,
+    pub number_of_linenumbers: u16,
+    pub check_sum: u32,
+    pub number: u32,
+    pub selection: u8,
+}
+
+/// Native endian version of [`pe::ImageRelocation`].
+#[allow(missing_docs)]
+#[derive(Debug, Default, Clone)]
+pub struct Relocation {
+    pub virtual_address: u32,
+    pub symbol: u32,
+    pub typ: u16,
+}
diff --git a/vendor/object/src/write/elf/mod.rs b/vendor/object/src/write/elf/mod.rs
new file mode 100644
index 0000000..3a4f371
--- /dev/null
+++ b/vendor/object/src/write/elf/mod.rs
@@ -0,0 +1,9 @@
+//! Support for writing ELF files.
+//!
+//! Provides [`Writer`] for low level writing of ELF files.
+//! This is also used to provide ELF support for [`write::Object`](crate::write::Object).
+
+mod object;
+
+mod writer;
+pub use writer::*;
diff --git a/vendor/object/src/write/elf/object.rs b/vendor/object/src/write/elf/object.rs
new file mode 100644
index 0000000..5d7a93e
--- /dev/null
+++ b/vendor/object/src/write/elf/object.rs
@@ -0,0 +1,907 @@
+use alloc::vec::Vec;
+
+use crate::write::elf::writer::*;
+use crate::write::string::StringId;
+use crate::write::*;
+use crate::AddressSize;
+use crate::{elf, pod};
+
+#[derive(Clone, Copy)]
+struct ComdatOffsets {
+    offset: usize,
+    str_id: StringId,
+}
+
+#[derive(Clone, Copy)]
+struct SectionOffsets {
+    index: SectionIndex,
+    offset: usize,
+    str_id: StringId,
+    reloc_offset: usize,
+    reloc_str_id: Option<StringId>,
+}
+
+#[derive(Default, Clone, Copy)]
+struct SymbolOffsets {
+    index: SymbolIndex,
+    str_id: Option<StringId>,
+}
+
+// Public methods.
+impl<'a> Object<'a> {
+    /// Add a property with a u32 value to the ELF ".note.gnu.property" section.
+    ///
+    /// Requires `feature = "elf"`.
+    pub fn add_elf_gnu_property_u32(&mut self, property: u32, value: u32) {
+        if self.format != BinaryFormat::Elf {
+            return;
+        }
+
+        let align = if self.elf_is_64() { 8 } else { 4 };
+        let mut data = Vec::with_capacity(32);
+        let n_name = b"GNU\0";
+        data.extend_from_slice(pod::bytes_of(&elf::NoteHeader32 {
+            n_namesz: U32::new(self.endian, n_name.len() as u32),
+            n_descsz: U32::new(self.endian, util::align(3 * 4, align) as u32),
+            n_type: U32::new(self.endian, elf::NT_GNU_PROPERTY_TYPE_0),
+        }));
+        data.extend_from_slice(n_name);
+        // This happens to already be aligned correctly.
+        debug_assert_eq!(util::align(data.len(), align), data.len());
+        data.extend_from_slice(pod::bytes_of(&U32::new(self.endian, property)));
+        // Value size
+        data.extend_from_slice(pod::bytes_of(&U32::new(self.endian, 4)));
+        data.extend_from_slice(pod::bytes_of(&U32::new(self.endian, value)));
+        util::write_align(&mut data, align);
+
+        let section = self.section_id(StandardSection::GnuProperty);
+        self.append_section_data(section, &data, align as u64);
+    }
+}
+
+// Private methods.
+impl<'a> Object<'a> {
+    pub(crate) fn elf_section_info(
+        &self,
+        section: StandardSection,
+    ) -> (&'static [u8], &'static [u8], SectionKind, SectionFlags) {
+        match section {
+            StandardSection::Text => (&[], &b".text"[..], SectionKind::Text, SectionFlags::None),
+            StandardSection::Data => (&[], &b".data"[..], SectionKind::Data, SectionFlags::None),
+            StandardSection::ReadOnlyData | StandardSection::ReadOnlyString => (
+                &[],
+                &b".rodata"[..],
+                SectionKind::ReadOnlyData,
+                SectionFlags::None,
+            ),
+            StandardSection::ReadOnlyDataWithRel => (
+                &[],
+                b".data.rel.ro",
+                SectionKind::ReadOnlyDataWithRel,
+                SectionFlags::None,
+            ),
+            StandardSection::UninitializedData => (
+                &[],
+                &b".bss"[..],
+                SectionKind::UninitializedData,
+                SectionFlags::None,
+            ),
+            StandardSection::Tls => (&[], &b".tdata"[..], SectionKind::Tls, SectionFlags::None),
+            StandardSection::UninitializedTls => (
+                &[],
+                &b".tbss"[..],
+                SectionKind::UninitializedTls,
+                SectionFlags::None,
+            ),
+            StandardSection::TlsVariables => {
+                // Unsupported section.
+                (&[], &[], SectionKind::TlsVariables, SectionFlags::None)
+            }
+            StandardSection::Common => {
+                // Unsupported section.
+                (&[], &[], SectionKind::Common, SectionFlags::None)
+            }
+            StandardSection::GnuProperty => (
+                &[],
+                &b".note.gnu.property"[..],
+                SectionKind::Note,
+                SectionFlags::Elf {
+                    sh_flags: u64::from(elf::SHF_ALLOC),
+                },
+            ),
+        }
+    }
+
+    pub(crate) fn elf_subsection_name(&self, section: &[u8], value: &[u8]) -> Vec<u8> {
+        let mut name = section.to_vec();
+        name.push(b'.');
+        name.extend_from_slice(value);
+        name
+    }
+
+    fn elf_has_relocation_addend(&self) -> Result<bool> {
+        Ok(match self.architecture {
+            Architecture::Aarch64 => true,
+            Architecture::Aarch64_Ilp32 => true,
+            Architecture::Arm => false,
+            Architecture::Avr => true,
+            Architecture::Bpf => false,
+            Architecture::Csky => true,
+            Architecture::I386 => false,
+            Architecture::X86_64 => true,
+            Architecture::X86_64_X32 => true,
+            Architecture::Hexagon => true,
+            Architecture::LoongArch64 => true,
+            Architecture::Mips => false,
+            Architecture::Mips64 => true,
+            Architecture::Msp430 => true,
+            Architecture::PowerPc => true,
+            Architecture::PowerPc64 => true,
+            Architecture::Riscv64 => true,
+            Architecture::Riscv32 => true,
+            Architecture::S390x => true,
+            Architecture::Sbf => false,
+            Architecture::Sharc => true,
+            Architecture::Sparc64 => true,
+            Architecture::Xtensa => true,
+            _ => {
+                return Err(Error(format!(
+                    "unimplemented architecture {:?}",
+                    self.architecture
+                )));
+            }
+        })
+    }
+
+    pub(crate) fn elf_fixup_relocation(&mut self, relocation: &mut Relocation) -> Result<i64> {
+        // Determine whether the addend is stored in the relocation or the data.
+        if self.elf_has_relocation_addend()? {
+            Ok(0)
+        } else {
+            let constant = relocation.addend;
+            relocation.addend = 0;
+            Ok(constant)
+        }
+    }
+
+    pub(crate) fn elf_is_64(&self) -> bool {
+        match self.architecture.address_size().unwrap() {
+            AddressSize::U8 | AddressSize::U16 | AddressSize::U32 => false,
+            AddressSize::U64 => true,
+        }
+    }
+
+    pub(crate) fn elf_write(&self, buffer: &mut dyn WritableBuffer) -> Result<()> {
+        // Create reloc section header names so we can reference them.
+        let is_rela = self.elf_has_relocation_addend()?;
+        let reloc_names: Vec<_> = self
+            .sections
+            .iter()
+            .map(|section| {
+                let mut reloc_name = Vec::with_capacity(
+                    if is_rela { ".rela".len() } else { ".rel".len() } + section.name.len(),
+                );
+                if !section.relocations.is_empty() {
+                    reloc_name.extend_from_slice(if is_rela {
+                        &b".rela"[..]
+                    } else {
+                        &b".rel"[..]
+                    });
+                    reloc_name.extend_from_slice(&section.name);
+                }
+                reloc_name
+            })
+            .collect();
+
+        // Start calculating offsets of everything.
+        let mut writer = Writer::new(self.endian, self.elf_is_64(), buffer);
+        writer.reserve_file_header();
+
+        // Calculate size of section data.
+        let mut comdat_offsets = Vec::with_capacity(self.comdats.len());
+        for comdat in &self.comdats {
+            if comdat.kind != ComdatKind::Any {
+                return Err(Error(format!(
+                    "unsupported COMDAT symbol `{}` kind {:?}",
+                    self.symbols[comdat.symbol.0].name().unwrap_or(""),
+                    comdat.kind
+                )));
+            }
+
+            writer.reserve_section_index();
+            let offset = writer.reserve_comdat(comdat.sections.len());
+            let str_id = writer.add_section_name(b".group");
+            comdat_offsets.push(ComdatOffsets { offset, str_id });
+        }
+        let mut section_offsets = Vec::with_capacity(self.sections.len());
+        for (section, reloc_name) in self.sections.iter().zip(reloc_names.iter()) {
+            let index = writer.reserve_section_index();
+            let offset = writer.reserve(section.data.len(), section.align as usize);
+            let str_id = writer.add_section_name(&section.name);
+            let mut reloc_str_id = None;
+            if !section.relocations.is_empty() {
+                writer.reserve_section_index();
+                reloc_str_id = Some(writer.add_section_name(reloc_name));
+            }
+            section_offsets.push(SectionOffsets {
+                index,
+                offset,
+                str_id,
+                // Relocation data is reserved later.
+                reloc_offset: 0,
+                reloc_str_id,
+            });
+        }
+
+        // Calculate index of symbols and add symbol strings to strtab.
+        let mut symbol_offsets = vec![SymbolOffsets::default(); self.symbols.len()];
+        writer.reserve_null_symbol_index();
+        // Local symbols must come before global.
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            if symbol.is_local() {
+                let section_index = symbol.section.id().map(|s| section_offsets[s.0].index);
+                symbol_offsets[index].index = writer.reserve_symbol_index(section_index);
+            }
+        }
+        let symtab_num_local = writer.symbol_count();
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            if !symbol.is_local() {
+                let section_index = symbol.section.id().map(|s| section_offsets[s.0].index);
+                symbol_offsets[index].index = writer.reserve_symbol_index(section_index);
+            }
+        }
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            if symbol.kind != SymbolKind::Section && !symbol.name.is_empty() {
+                symbol_offsets[index].str_id = Some(writer.add_string(&symbol.name));
+            }
+        }
+
+        // Calculate size of symbols.
+        writer.reserve_symtab_section_index();
+        writer.reserve_symtab();
+        if writer.symtab_shndx_needed() {
+            writer.reserve_symtab_shndx_section_index();
+        }
+        writer.reserve_symtab_shndx();
+        writer.reserve_strtab_section_index();
+        writer.reserve_strtab();
+
+        // Calculate size of relocations.
+        for (index, section) in self.sections.iter().enumerate() {
+            let count = section.relocations.len();
+            if count != 0 {
+                section_offsets[index].reloc_offset = writer.reserve_relocations(count, is_rela);
+            }
+        }
+
+        // Calculate size of section headers.
+        writer.reserve_shstrtab_section_index();
+        writer.reserve_shstrtab();
+        writer.reserve_section_headers();
+
+        // Start writing.
+        let e_type = elf::ET_REL;
+        let e_machine = match (self.architecture, self.sub_architecture) {
+            (Architecture::Aarch64, None) => elf::EM_AARCH64,
+            (Architecture::Aarch64_Ilp32, None) => elf::EM_AARCH64,
+            (Architecture::Arm, None) => elf::EM_ARM,
+            (Architecture::Avr, None) => elf::EM_AVR,
+            (Architecture::Bpf, None) => elf::EM_BPF,
+            (Architecture::Csky, None) => elf::EM_CSKY,
+            (Architecture::I386, None) => elf::EM_386,
+            (Architecture::X86_64, None) => elf::EM_X86_64,
+            (Architecture::X86_64_X32, None) => elf::EM_X86_64,
+            (Architecture::Hexagon, None) => elf::EM_HEXAGON,
+            (Architecture::LoongArch64, None) => elf::EM_LOONGARCH,
+            (Architecture::Mips, None) => elf::EM_MIPS,
+            (Architecture::Mips64, None) => elf::EM_MIPS,
+            (Architecture::Msp430, None) => elf::EM_MSP430,
+            (Architecture::PowerPc, None) => elf::EM_PPC,
+            (Architecture::PowerPc64, None) => elf::EM_PPC64,
+            (Architecture::Riscv32, None) => elf::EM_RISCV,
+            (Architecture::Riscv64, None) => elf::EM_RISCV,
+            (Architecture::S390x, None) => elf::EM_S390,
+            (Architecture::Sbf, None) => elf::EM_SBF,
+            (Architecture::Sharc, None) => elf::EM_SHARC,
+            (Architecture::Sparc64, None) => elf::EM_SPARCV9,
+            (Architecture::Xtensa, None) => elf::EM_XTENSA,
+            _ => {
+                return Err(Error(format!(
+                    "unimplemented architecture {:?} with sub-architecture {:?}",
+                    self.architecture, self.sub_architecture
+                )));
+            }
+        };
+        let (os_abi, abi_version, e_flags) = if let FileFlags::Elf {
+            os_abi,
+            abi_version,
+            e_flags,
+        } = self.flags
+        {
+            (os_abi, abi_version, e_flags)
+        } else {
+            (elf::ELFOSABI_NONE, 0, 0)
+        };
+        writer.write_file_header(&FileHeader {
+            os_abi,
+            abi_version,
+            e_type,
+            e_machine,
+            e_entry: 0,
+            e_flags,
+        })?;
+
+        // Write section data.
+        for comdat in &self.comdats {
+            writer.write_comdat_header();
+            for section in &comdat.sections {
+                writer.write_comdat_entry(section_offsets[section.0].index);
+            }
+        }
+        for (index, section) in self.sections.iter().enumerate() {
+            writer.write_align(section.align as usize);
+            debug_assert_eq!(section_offsets[index].offset, writer.len());
+            writer.write(&section.data);
+        }
+
+        // Write symbols.
+        writer.write_null_symbol();
+        let mut write_symbol = |index: usize, symbol: &Symbol| -> Result<()> {
+            let st_info = if let SymbolFlags::Elf { st_info, .. } = symbol.flags {
+                st_info
+            } else {
+                let st_type = match symbol.kind {
+                    SymbolKind::Null => elf::STT_NOTYPE,
+                    SymbolKind::Text => {
+                        if symbol.is_undefined() {
+                            elf::STT_NOTYPE
+                        } else {
+                            elf::STT_FUNC
+                        }
+                    }
+                    SymbolKind::Data => {
+                        if symbol.is_undefined() {
+                            elf::STT_NOTYPE
+                        } else if symbol.is_common() {
+                            elf::STT_COMMON
+                        } else {
+                            elf::STT_OBJECT
+                        }
+                    }
+                    SymbolKind::Section => elf::STT_SECTION,
+                    SymbolKind::File => elf::STT_FILE,
+                    SymbolKind::Tls => elf::STT_TLS,
+                    SymbolKind::Label => elf::STT_NOTYPE,
+                    SymbolKind::Unknown => {
+                        if symbol.is_undefined() {
+                            elf::STT_NOTYPE
+                        } else {
+                            return Err(Error(format!(
+                                "unimplemented symbol `{}` kind {:?}",
+                                symbol.name().unwrap_or(""),
+                                symbol.kind
+                            )));
+                        }
+                    }
+                };
+                let st_bind = if symbol.weak {
+                    elf::STB_WEAK
+                } else if symbol.is_undefined() {
+                    elf::STB_GLOBAL
+                } else if symbol.is_local() {
+                    elf::STB_LOCAL
+                } else {
+                    elf::STB_GLOBAL
+                };
+                (st_bind << 4) + st_type
+            };
+            let st_other = if let SymbolFlags::Elf { st_other, .. } = symbol.flags {
+                st_other
+            } else if symbol.scope == SymbolScope::Linkage {
+                elf::STV_HIDDEN
+            } else {
+                elf::STV_DEFAULT
+            };
+            let (st_shndx, section) = match symbol.section {
+                SymbolSection::None => {
+                    debug_assert_eq!(symbol.kind, SymbolKind::File);
+                    (elf::SHN_ABS, None)
+                }
+                SymbolSection::Undefined => (elf::SHN_UNDEF, None),
+                SymbolSection::Absolute => (elf::SHN_ABS, None),
+                SymbolSection::Common => (elf::SHN_COMMON, None),
+                SymbolSection::Section(id) => (0, Some(section_offsets[id.0].index)),
+            };
+            writer.write_symbol(&Sym {
+                name: symbol_offsets[index].str_id,
+                section,
+                st_info,
+                st_other,
+                st_shndx,
+                st_value: symbol.value,
+                st_size: symbol.size,
+            });
+            Ok(())
+        };
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            if symbol.is_local() {
+                write_symbol(index, symbol)?;
+            }
+        }
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            if !symbol.is_local() {
+                write_symbol(index, symbol)?;
+            }
+        }
+        writer.write_symtab_shndx();
+        writer.write_strtab();
+
+        // Write relocations.
+        for (index, section) in self.sections.iter().enumerate() {
+            if !section.relocations.is_empty() {
+                writer.write_align_relocation();
+                debug_assert_eq!(section_offsets[index].reloc_offset, writer.len());
+                for reloc in &section.relocations {
+                    let r_type = match self.architecture {
+                        Architecture::Aarch64 => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 64) => {
+                                elf::R_AARCH64_ABS64
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 32) => {
+                                elf::R_AARCH64_ABS32
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 16) => {
+                                elf::R_AARCH64_ABS16
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 64) => {
+                                elf::R_AARCH64_PREL64
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
+                                elf::R_AARCH64_PREL32
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 16) => {
+                                elf::R_AARCH64_PREL16
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::AArch64Call, 26)
+                            | (RelocationKind::PltRelative, RelocationEncoding::AArch64Call, 26) => {
+                                elf::R_AARCH64_CALL26
+                            }
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Aarch64_Ilp32 => {
+                            match (reloc.kind, reloc.encoding, reloc.size) {
+                                (RelocationKind::Absolute, RelocationEncoding::Generic, 32) => {
+                                    elf::R_AARCH64_P32_ABS32
+                                }
+                                (RelocationKind::Elf(x), _, _) => x,
+                                _ => {
+                                    return Err(Error(format!(
+                                        "unimplemented relocation {:?}",
+                                        reloc
+                                    )));
+                                }
+                            }
+                        }
+                        Architecture::Arm => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_ARM_ABS32,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Avr => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_AVR_32,
+                            (RelocationKind::Absolute, _, 16) => elf::R_AVR_16,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Bpf => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 64) => elf::R_BPF_64_64,
+                            (RelocationKind::Absolute, _, 32) => elf::R_BPF_64_32,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Csky => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_CKCORE_ADDR32,
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
+                                elf::R_CKCORE_PCREL32
+                            }
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::I386 => match (reloc.kind, reloc.size) {
+                            (RelocationKind::Absolute, 32) => elf::R_386_32,
+                            (RelocationKind::Relative, 32) => elf::R_386_PC32,
+                            (RelocationKind::Got, 32) => elf::R_386_GOT32,
+                            (RelocationKind::PltRelative, 32) => elf::R_386_PLT32,
+                            (RelocationKind::GotBaseOffset, 32) => elf::R_386_GOTOFF,
+                            (RelocationKind::GotBaseRelative, 32) => elf::R_386_GOTPC,
+                            (RelocationKind::Absolute, 16) => elf::R_386_16,
+                            (RelocationKind::Relative, 16) => elf::R_386_PC16,
+                            (RelocationKind::Absolute, 8) => elf::R_386_8,
+                            (RelocationKind::Relative, 8) => elf::R_386_PC8,
+                            (RelocationKind::Elf(x), _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::X86_64 | Architecture::X86_64_X32 => {
+                            match (reloc.kind, reloc.encoding, reloc.size) {
+                                (RelocationKind::Absolute, RelocationEncoding::Generic, 64) => {
+                                    elf::R_X86_64_64
+                                }
+                                (RelocationKind::Relative, RelocationEncoding::X86Branch, 32) => {
+                                    elf::R_X86_64_PLT32
+                                }
+                                (RelocationKind::Relative, _, 32) => elf::R_X86_64_PC32,
+                                (RelocationKind::Got, _, 32) => elf::R_X86_64_GOT32,
+                                (RelocationKind::PltRelative, _, 32) => elf::R_X86_64_PLT32,
+                                (RelocationKind::GotRelative, _, 32) => elf::R_X86_64_GOTPCREL,
+                                (RelocationKind::Absolute, RelocationEncoding::Generic, 32) => {
+                                    elf::R_X86_64_32
+                                }
+                                (RelocationKind::Absolute, RelocationEncoding::X86Signed, 32) => {
+                                    elf::R_X86_64_32S
+                                }
+                                (RelocationKind::Absolute, _, 16) => elf::R_X86_64_16,
+                                (RelocationKind::Relative, _, 16) => elf::R_X86_64_PC16,
+                                (RelocationKind::Absolute, _, 8) => elf::R_X86_64_8,
+                                (RelocationKind::Relative, _, 8) => elf::R_X86_64_PC8,
+                                (RelocationKind::Elf(x), _, _) => x,
+                                _ => {
+                                    return Err(Error(format!(
+                                        "unimplemented relocation {:?}",
+                                        reloc
+                                    )));
+                                }
+                            }
+                        }
+                        Architecture::Hexagon => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_HEX_32,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::LoongArch64 => match (reloc.kind, reloc.encoding, reloc.size)
+                        {
+                            (RelocationKind::Absolute, _, 32) => elf::R_LARCH_32,
+                            (RelocationKind::Absolute, _, 64) => elf::R_LARCH_64,
+                            (RelocationKind::Relative, _, 32) => elf::R_LARCH_32_PCREL,
+                            (RelocationKind::Relative, _, 64) => elf::R_LARCH_64_PCREL,
+                            (RelocationKind::Relative, RelocationEncoding::LoongArchBranch, 16)
+                            | (
+                                RelocationKind::PltRelative,
+                                RelocationEncoding::LoongArchBranch,
+                                16,
+                            ) => elf::R_LARCH_B16,
+                            (RelocationKind::Relative, RelocationEncoding::LoongArchBranch, 21)
+                            | (
+                                RelocationKind::PltRelative,
+                                RelocationEncoding::LoongArchBranch,
+                                21,
+                            ) => elf::R_LARCH_B21,
+                            (RelocationKind::Relative, RelocationEncoding::LoongArchBranch, 26)
+                            | (
+                                RelocationKind::PltRelative,
+                                RelocationEncoding::LoongArchBranch,
+                                26,
+                            ) => elf::R_LARCH_B26,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Mips | Architecture::Mips64 => {
+                            match (reloc.kind, reloc.encoding, reloc.size) {
+                                (RelocationKind::Absolute, _, 16) => elf::R_MIPS_16,
+                                (RelocationKind::Absolute, _, 32) => elf::R_MIPS_32,
+                                (RelocationKind::Absolute, _, 64) => elf::R_MIPS_64,
+                                (RelocationKind::Elf(x), _, _) => x,
+                                _ => {
+                                    return Err(Error(format!(
+                                        "unimplemented relocation {:?}",
+                                        reloc
+                                    )));
+                                }
+                            }
+                        }
+                        Architecture::Msp430 => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_MSP430_32,
+                            (RelocationKind::Absolute, _, 16) => elf::R_MSP430_16_BYTE,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::PowerPc => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_PPC_ADDR32,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::PowerPc64 => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_PPC64_ADDR32,
+                            (RelocationKind::Absolute, _, 64) => elf::R_PPC64_ADDR64,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Riscv32 | Architecture::Riscv64 => {
+                            match (reloc.kind, reloc.encoding, reloc.size) {
+                                (RelocationKind::Absolute, _, 32) => elf::R_RISCV_32,
+                                (RelocationKind::Absolute, _, 64) => elf::R_RISCV_64,
+                                (RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
+                                    elf::R_RISCV_32_PCREL
+                                }
+                                (RelocationKind::Elf(x), _, _) => x,
+                                _ => {
+                                    return Err(Error(format!(
+                                        "unimplemented relocation {:?}",
+                                        reloc
+                                    )));
+                                }
+                            }
+                        }
+                        Architecture::S390x => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 8) => {
+                                elf::R_390_8
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 16) => {
+                                elf::R_390_16
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 32) => {
+                                elf::R_390_32
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 64) => {
+                                elf::R_390_64
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 16) => {
+                                elf::R_390_PC16
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
+                                elf::R_390_PC32
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 64) => {
+                                elf::R_390_PC64
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::S390xDbl, 16) => {
+                                elf::R_390_PC16DBL
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::S390xDbl, 32) => {
+                                elf::R_390_PC32DBL
+                            }
+                            (RelocationKind::PltRelative, RelocationEncoding::S390xDbl, 16) => {
+                                elf::R_390_PLT16DBL
+                            }
+                            (RelocationKind::PltRelative, RelocationEncoding::S390xDbl, 32) => {
+                                elf::R_390_PLT32DBL
+                            }
+                            (RelocationKind::Got, RelocationEncoding::Generic, 16) => {
+                                elf::R_390_GOT16
+                            }
+                            (RelocationKind::Got, RelocationEncoding::Generic, 32) => {
+                                elf::R_390_GOT32
+                            }
+                            (RelocationKind::Got, RelocationEncoding::Generic, 64) => {
+                                elf::R_390_GOT64
+                            }
+                            (RelocationKind::GotRelative, RelocationEncoding::S390xDbl, 32) => {
+                                elf::R_390_GOTENT
+                            }
+                            (RelocationKind::GotBaseOffset, RelocationEncoding::Generic, 16) => {
+                                elf::R_390_GOTOFF16
+                            }
+                            (RelocationKind::GotBaseOffset, RelocationEncoding::Generic, 32) => {
+                                elf::R_390_GOTOFF32
+                            }
+                            (RelocationKind::GotBaseOffset, RelocationEncoding::Generic, 64) => {
+                                elf::R_390_GOTOFF64
+                            }
+                            (RelocationKind::GotBaseRelative, RelocationEncoding::Generic, 64) => {
+                                elf::R_390_GOTPC
+                            }
+                            (RelocationKind::GotBaseRelative, RelocationEncoding::S390xDbl, 32) => {
+                                elf::R_390_GOTPCDBL
+                            }
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Sbf => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 64) => elf::R_SBF_64_64,
+                            (RelocationKind::Absolute, _, 32) => elf::R_SBF_64_32,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Sharc => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 32) => {
+                                elf::R_SHARC_ADDR32_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 32) => {
+                                elf::R_SHARC_ADDR_VAR_V3
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::SharcTypeA, 24) => {
+                                elf::R_SHARC_PCRLONG_V3
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::SharcTypeA, 6) => {
+                                elf::R_SHARC_PCRSHORT_V3
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::SharcTypeB, 6) => {
+                                elf::R_SHARC_PCRSHORT_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::Generic, 16) => {
+                                elf::R_SHARC_ADDR_VAR16_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 16) => {
+                                elf::R_SHARC_DATA16_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::SharcTypeB, 16) => {
+                                elf::R_SHARC_DATA16_VISA_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 24) => {
+                                elf::R_SHARC_ADDR24_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::SharcTypeA, 6) => {
+                                elf::R_SHARC_DATA6_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::SharcTypeB, 6) => {
+                                elf::R_SHARC_DATA6_VISA_V3
+                            }
+                            (RelocationKind::Absolute, RelocationEncoding::SharcTypeB, 7) => {
+                                elf::R_SHARC_DATA7_VISA_V3
+                            }
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Sparc64 => match (reloc.kind, reloc.encoding, reloc.size) {
+                            // TODO: use R_SPARC_32/R_SPARC_64 if aligned.
+                            (RelocationKind::Absolute, _, 32) => elf::R_SPARC_UA32,
+                            (RelocationKind::Absolute, _, 64) => elf::R_SPARC_UA64,
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Xtensa => match (reloc.kind, reloc.encoding, reloc.size) {
+                            (RelocationKind::Absolute, _, 32) => elf::R_XTENSA_32,
+                            (RelocationKind::Relative, RelocationEncoding::Generic, 32) => {
+                                elf::R_XTENSA_32_PCREL
+                            }
+                            (RelocationKind::Elf(x), _, _) => x,
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        _ => {
+                            if let RelocationKind::Elf(x) = reloc.kind {
+                                x
+                            } else {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        }
+                    };
+                    let r_sym = symbol_offsets[reloc.symbol.0].index.0;
+                    writer.write_relocation(
+                        is_rela,
+                        &Rel {
+                            r_offset: reloc.offset,
+                            r_sym,
+                            r_type,
+                            r_addend: reloc.addend,
+                        },
+                    );
+                }
+            }
+        }
+
+        writer.write_shstrtab();
+
+        // Write section headers.
+        writer.write_null_section_header();
+
+        let symtab_index = writer.symtab_index();
+        for (comdat, comdat_offset) in self.comdats.iter().zip(comdat_offsets.iter()) {
+            writer.write_comdat_section_header(
+                comdat_offset.str_id,
+                symtab_index,
+                symbol_offsets[comdat.symbol.0].index,
+                comdat_offset.offset,
+                comdat.sections.len(),
+            );
+        }
+        for (index, section) in self.sections.iter().enumerate() {
+            let sh_type = match section.kind {
+                SectionKind::UninitializedData | SectionKind::UninitializedTls => elf::SHT_NOBITS,
+                SectionKind::Note => elf::SHT_NOTE,
+                SectionKind::Elf(sh_type) => sh_type,
+                _ => elf::SHT_PROGBITS,
+            };
+            let sh_flags = if let SectionFlags::Elf { sh_flags } = section.flags {
+                sh_flags
+            } else {
+                match section.kind {
+                    SectionKind::Text => elf::SHF_ALLOC | elf::SHF_EXECINSTR,
+                    SectionKind::Data | SectionKind::ReadOnlyDataWithRel => {
+                        elf::SHF_ALLOC | elf::SHF_WRITE
+                    }
+                    SectionKind::Tls => elf::SHF_ALLOC | elf::SHF_WRITE | elf::SHF_TLS,
+                    SectionKind::UninitializedData => elf::SHF_ALLOC | elf::SHF_WRITE,
+                    SectionKind::UninitializedTls => elf::SHF_ALLOC | elf::SHF_WRITE | elf::SHF_TLS,
+                    SectionKind::ReadOnlyData => elf::SHF_ALLOC,
+                    SectionKind::ReadOnlyString => {
+                        elf::SHF_ALLOC | elf::SHF_STRINGS | elf::SHF_MERGE
+                    }
+                    SectionKind::OtherString => elf::SHF_STRINGS | elf::SHF_MERGE,
+                    SectionKind::Other
+                    | SectionKind::Debug
+                    | SectionKind::Metadata
+                    | SectionKind::Linker
+                    | SectionKind::Note
+                    | SectionKind::Elf(_) => 0,
+                    SectionKind::Unknown | SectionKind::Common | SectionKind::TlsVariables => {
+                        return Err(Error(format!(
+                            "unimplemented section `{}` kind {:?}",
+                            section.name().unwrap_or(""),
+                            section.kind
+                        )));
+                    }
+                }
+                .into()
+            };
+            // TODO: not sure if this is correct, maybe user should determine this
+            let sh_entsize = match section.kind {
+                SectionKind::ReadOnlyString | SectionKind::OtherString => 1,
+                _ => 0,
+            };
+            writer.write_section_header(&SectionHeader {
+                name: Some(section_offsets[index].str_id),
+                sh_type,
+                sh_flags,
+                sh_addr: 0,
+                sh_offset: section_offsets[index].offset as u64,
+                sh_size: section.size,
+                sh_link: 0,
+                sh_info: 0,
+                sh_addralign: section.align,
+                sh_entsize,
+            });
+
+            if !section.relocations.is_empty() {
+                writer.write_relocation_section_header(
+                    section_offsets[index].reloc_str_id.unwrap(),
+                    section_offsets[index].index,
+                    symtab_index,
+                    section_offsets[index].reloc_offset,
+                    section.relocations.len(),
+                    is_rela,
+                );
+            }
+        }
+
+        writer.write_symtab_section_header(symtab_num_local);
+        writer.write_symtab_shndx_section_header();
+        writer.write_strtab_section_header();
+        writer.write_shstrtab_section_header();
+
+        debug_assert_eq!(writer.reserved_len(), writer.len());
+
+        Ok(())
+    }
+}
diff --git a/vendor/object/src/write/elf/writer.rs b/vendor/object/src/write/elf/writer.rs
new file mode 100644
index 0000000..9750924
--- /dev/null
+++ b/vendor/object/src/write/elf/writer.rs
@@ -0,0 +1,2143 @@
+//! Helper for writing ELF files.
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::mem;
+
+use crate::elf;
+use crate::endian::*;
+use crate::pod;
+use crate::write::string::{StringId, StringTable};
+use crate::write::util;
+use crate::write::{Error, Result, WritableBuffer};
+
+/// The index of an ELF section.
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SectionIndex(pub u32);
+
+/// The index of an ELF symbol.
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SymbolIndex(pub u32);
+
+/// A helper for writing ELF files.
+///
+/// Writing uses a two phase approach. The first phase builds up all of the information
+/// that may need to be known ahead of time:
+/// - build string tables
+/// - reserve section indices
+/// - reserve symbol indices
+/// - reserve file ranges for headers and sections
+///
+/// Some of the information has ordering requirements. For example, strings must be added
+/// to string tables before reserving the file range for the string table. Symbol indices
+/// must be reserved after reserving the section indices they reference. There are debug
+/// asserts to check some of these requirements.
+///
+/// The second phase writes everything out in order. Thus the caller must ensure writing
+/// is in the same order that file ranges were reserved. There are debug asserts to assist
+/// with checking this.
+#[allow(missing_debug_implementations)]
+pub struct Writer<'a> {
+    endian: Endianness,
+    is_64: bool,
+    is_mips64el: bool,
+    elf_align: usize,
+
+    buffer: &'a mut dyn WritableBuffer,
+    len: usize,
+
+    segment_offset: usize,
+    segment_num: u32,
+
+    section_offset: usize,
+    section_num: u32,
+
+    shstrtab: StringTable<'a>,
+    shstrtab_str_id: Option<StringId>,
+    shstrtab_index: SectionIndex,
+    shstrtab_offset: usize,
+    shstrtab_data: Vec<u8>,
+
+    need_strtab: bool,
+    strtab: StringTable<'a>,
+    strtab_str_id: Option<StringId>,
+    strtab_index: SectionIndex,
+    strtab_offset: usize,
+    strtab_data: Vec<u8>,
+
+    symtab_str_id: Option<StringId>,
+    symtab_index: SectionIndex,
+    symtab_offset: usize,
+    symtab_num: u32,
+
+    need_symtab_shndx: bool,
+    symtab_shndx_str_id: Option<StringId>,
+    symtab_shndx_offset: usize,
+    symtab_shndx_data: Vec<u8>,
+
+    need_dynstr: bool,
+    dynstr: StringTable<'a>,
+    dynstr_str_id: Option<StringId>,
+    dynstr_index: SectionIndex,
+    dynstr_offset: usize,
+    dynstr_data: Vec<u8>,
+
+    dynsym_str_id: Option<StringId>,
+    dynsym_index: SectionIndex,
+    dynsym_offset: usize,
+    dynsym_num: u32,
+
+    dynamic_str_id: Option<StringId>,
+    dynamic_offset: usize,
+    dynamic_num: usize,
+
+    hash_str_id: Option<StringId>,
+    hash_offset: usize,
+    hash_size: usize,
+
+    gnu_hash_str_id: Option<StringId>,
+    gnu_hash_offset: usize,
+    gnu_hash_size: usize,
+
+    gnu_versym_str_id: Option<StringId>,
+    gnu_versym_offset: usize,
+
+    gnu_verdef_str_id: Option<StringId>,
+    gnu_verdef_offset: usize,
+    gnu_verdef_size: usize,
+    gnu_verdef_count: u16,
+    gnu_verdef_remaining: u16,
+    gnu_verdaux_remaining: u16,
+
+    gnu_verneed_str_id: Option<StringId>,
+    gnu_verneed_offset: usize,
+    gnu_verneed_size: usize,
+    gnu_verneed_count: u16,
+    gnu_verneed_remaining: u16,
+    gnu_vernaux_remaining: u16,
+
+    gnu_attributes_str_id: Option<StringId>,
+    gnu_attributes_offset: usize,
+    gnu_attributes_size: usize,
+}
+
+impl<'a> Writer<'a> {
+    /// Create a new `Writer` for the given endianness and ELF class.
+    pub fn new(endian: Endianness, is_64: bool, buffer: &'a mut dyn WritableBuffer) -> Self {
+        let elf_align = if is_64 { 8 } else { 4 };
+        Writer {
+            endian,
+            is_64,
+            // Determined later.
+            is_mips64el: false,
+            elf_align,
+
+            buffer,
+            len: 0,
+
+            segment_offset: 0,
+            segment_num: 0,
+
+            section_offset: 0,
+            section_num: 0,
+
+            shstrtab: StringTable::default(),
+            shstrtab_str_id: None,
+            shstrtab_index: SectionIndex(0),
+            shstrtab_offset: 0,
+            shstrtab_data: Vec::new(),
+
+            need_strtab: false,
+            strtab: StringTable::default(),
+            strtab_str_id: None,
+            strtab_index: SectionIndex(0),
+            strtab_offset: 0,
+            strtab_data: Vec::new(),
+
+            symtab_str_id: None,
+            symtab_index: SectionIndex(0),
+            symtab_offset: 0,
+            symtab_num: 0,
+
+            need_symtab_shndx: false,
+            symtab_shndx_str_id: None,
+            symtab_shndx_offset: 0,
+            symtab_shndx_data: Vec::new(),
+
+            need_dynstr: false,
+            dynstr: StringTable::default(),
+            dynstr_str_id: None,
+            dynstr_index: SectionIndex(0),
+            dynstr_offset: 0,
+            dynstr_data: Vec::new(),
+
+            dynsym_str_id: None,
+            dynsym_index: SectionIndex(0),
+            dynsym_offset: 0,
+            dynsym_num: 0,
+
+            dynamic_str_id: None,
+            dynamic_offset: 0,
+            dynamic_num: 0,
+
+            hash_str_id: None,
+            hash_offset: 0,
+            hash_size: 0,
+
+            gnu_hash_str_id: None,
+            gnu_hash_offset: 0,
+            gnu_hash_size: 0,
+
+            gnu_versym_str_id: None,
+            gnu_versym_offset: 0,
+
+            gnu_verdef_str_id: None,
+            gnu_verdef_offset: 0,
+            gnu_verdef_size: 0,
+            gnu_verdef_count: 0,
+            gnu_verdef_remaining: 0,
+            gnu_verdaux_remaining: 0,
+
+            gnu_verneed_str_id: None,
+            gnu_verneed_offset: 0,
+            gnu_verneed_size: 0,
+            gnu_verneed_count: 0,
+            gnu_verneed_remaining: 0,
+            gnu_vernaux_remaining: 0,
+
+            gnu_attributes_str_id: None,
+            gnu_attributes_offset: 0,
+            gnu_attributes_size: 0,
+        }
+    }
+
+    /// Return the current file length that has been reserved.
+    pub fn reserved_len(&self) -> usize {
+        self.len
+    }
+
+    /// Return the current file length that has been written.
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> usize {
+        self.buffer.len()
+    }
+
+    /// Reserve a file range with the given size and starting alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve(&mut self, len: usize, align_start: usize) -> usize {
+        if align_start > 1 {
+            self.len = util::align(self.len, align_start);
+        }
+        let offset = self.len;
+        self.len += len;
+        offset
+    }
+
+    /// Write alignment padding bytes.
+    pub fn write_align(&mut self, align_start: usize) {
+        if align_start > 1 {
+            util::write_align(self.buffer, align_start);
+        }
+    }
+
+    /// Write data.
+    ///
+    /// This is typically used to write section data.
+    pub fn write(&mut self, data: &[u8]) {
+        self.buffer.write_bytes(data);
+    }
+
+    /// Reserve the file range up to the given file offset.
+    pub fn reserve_until(&mut self, offset: usize) {
+        debug_assert!(self.len <= offset);
+        self.len = offset;
+    }
+
+    /// Write padding up to the given file offset.
+    pub fn pad_until(&mut self, offset: usize) {
+        debug_assert!(self.buffer.len() <= offset);
+        self.buffer.resize(offset);
+    }
+
+    fn file_header_size(&self) -> usize {
+        if self.is_64 {
+            mem::size_of::<elf::FileHeader64<Endianness>>()
+        } else {
+            mem::size_of::<elf::FileHeader32<Endianness>>()
+        }
+    }
+
+    /// Reserve the range for the file header.
+    ///
+    /// This must be at the start of the file.
+    pub fn reserve_file_header(&mut self) {
+        debug_assert_eq!(self.len, 0);
+        self.reserve(self.file_header_size(), 1);
+    }
+
+    /// Write the file header.
+    ///
+    /// This must be at the start of the file.
+    ///
+    /// Fields that can be derived from known information are automatically set by this function.
+    pub fn write_file_header(&mut self, header: &FileHeader) -> Result<()> {
+        debug_assert_eq!(self.buffer.len(), 0);
+
+        self.is_mips64el =
+            self.is_64 && self.endian.is_little_endian() && header.e_machine == elf::EM_MIPS;
+
+        // Start writing.
+        self.buffer
+            .reserve(self.len)
+            .map_err(|_| Error(String::from("Cannot allocate buffer")))?;
+
+        // Write file header.
+        let e_ident = elf::Ident {
+            magic: elf::ELFMAG,
+            class: if self.is_64 {
+                elf::ELFCLASS64
+            } else {
+                elf::ELFCLASS32
+            },
+            data: if self.endian.is_little_endian() {
+                elf::ELFDATA2LSB
+            } else {
+                elf::ELFDATA2MSB
+            },
+            version: elf::EV_CURRENT,
+            os_abi: header.os_abi,
+            abi_version: header.abi_version,
+            padding: [0; 7],
+        };
+
+        let e_ehsize = self.file_header_size() as u16;
+
+        let e_phoff = self.segment_offset as u64;
+        let e_phentsize = if self.segment_num == 0 {
+            0
+        } else {
+            self.program_header_size() as u16
+        };
+        // TODO: overflow
+        let e_phnum = self.segment_num as u16;
+
+        let e_shoff = self.section_offset as u64;
+        let e_shentsize = if self.section_num == 0 {
+            0
+        } else {
+            self.section_header_size() as u16
+        };
+        let e_shnum = if self.section_num >= elf::SHN_LORESERVE.into() {
+            0
+        } else {
+            self.section_num as u16
+        };
+        let e_shstrndx = if self.shstrtab_index.0 >= elf::SHN_LORESERVE.into() {
+            elf::SHN_XINDEX
+        } else {
+            self.shstrtab_index.0 as u16
+        };
+
+        let endian = self.endian;
+        if self.is_64 {
+            let file = elf::FileHeader64 {
+                e_ident,
+                e_type: U16::new(endian, header.e_type),
+                e_machine: U16::new(endian, header.e_machine),
+                e_version: U32::new(endian, elf::EV_CURRENT.into()),
+                e_entry: U64::new(endian, header.e_entry),
+                e_phoff: U64::new(endian, e_phoff),
+                e_shoff: U64::new(endian, e_shoff),
+                e_flags: U32::new(endian, header.e_flags),
+                e_ehsize: U16::new(endian, e_ehsize),
+                e_phentsize: U16::new(endian, e_phentsize),
+                e_phnum: U16::new(endian, e_phnum),
+                e_shentsize: U16::new(endian, e_shentsize),
+                e_shnum: U16::new(endian, e_shnum),
+                e_shstrndx: U16::new(endian, e_shstrndx),
+            };
+            self.buffer.write(&file)
+        } else {
+            let file = elf::FileHeader32 {
+                e_ident,
+                e_type: U16::new(endian, header.e_type),
+                e_machine: U16::new(endian, header.e_machine),
+                e_version: U32::new(endian, elf::EV_CURRENT.into()),
+                e_entry: U32::new(endian, header.e_entry as u32),
+                e_phoff: U32::new(endian, e_phoff as u32),
+                e_shoff: U32::new(endian, e_shoff as u32),
+                e_flags: U32::new(endian, header.e_flags),
+                e_ehsize: U16::new(endian, e_ehsize),
+                e_phentsize: U16::new(endian, e_phentsize),
+                e_phnum: U16::new(endian, e_phnum),
+                e_shentsize: U16::new(endian, e_shentsize),
+                e_shnum: U16::new(endian, e_shnum),
+                e_shstrndx: U16::new(endian, e_shstrndx),
+            };
+            self.buffer.write(&file);
+        }
+
+        Ok(())
+    }
+
+    fn program_header_size(&self) -> usize {
+        if self.is_64 {
+            mem::size_of::<elf::ProgramHeader64<Endianness>>()
+        } else {
+            mem::size_of::<elf::ProgramHeader32<Endianness>>()
+        }
+    }
+
+    /// Reserve the range for the program headers.
+    pub fn reserve_program_headers(&mut self, num: u32) {
+        debug_assert_eq!(self.segment_offset, 0);
+        if num == 0 {
+            return;
+        }
+        self.segment_num = num;
+        self.segment_offset =
+            self.reserve(num as usize * self.program_header_size(), self.elf_align);
+    }
+
+    /// Write alignment padding bytes prior to the program headers.
+    pub fn write_align_program_headers(&mut self) {
+        if self.segment_offset == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.segment_offset, self.buffer.len());
+    }
+
+    /// Write a program header.
+    pub fn write_program_header(&mut self, header: &ProgramHeader) {
+        let endian = self.endian;
+        if self.is_64 {
+            let header = elf::ProgramHeader64 {
+                p_type: U32::new(endian, header.p_type),
+                p_flags: U32::new(endian, header.p_flags),
+                p_offset: U64::new(endian, header.p_offset),
+                p_vaddr: U64::new(endian, header.p_vaddr),
+                p_paddr: U64::new(endian, header.p_paddr),
+                p_filesz: U64::new(endian, header.p_filesz),
+                p_memsz: U64::new(endian, header.p_memsz),
+                p_align: U64::new(endian, header.p_align),
+            };
+            self.buffer.write(&header);
+        } else {
+            let header = elf::ProgramHeader32 {
+                p_type: U32::new(endian, header.p_type),
+                p_offset: U32::new(endian, header.p_offset as u32),
+                p_vaddr: U32::new(endian, header.p_vaddr as u32),
+                p_paddr: U32::new(endian, header.p_paddr as u32),
+                p_filesz: U32::new(endian, header.p_filesz as u32),
+                p_memsz: U32::new(endian, header.p_memsz as u32),
+                p_flags: U32::new(endian, header.p_flags),
+                p_align: U32::new(endian, header.p_align as u32),
+            };
+            self.buffer.write(&header);
+        }
+    }
+
+    /// Reserve the section index for the null section header.
+    ///
+    /// The null section header is usually automatically reserved,
+    /// but this can be used to force an empty section table.
+    ///
+    /// This must be called before [`Self::reserve_section_headers`].
+    pub fn reserve_null_section_index(&mut self) -> SectionIndex {
+        debug_assert_eq!(self.section_num, 0);
+        if self.section_num == 0 {
+            self.section_num = 1;
+        }
+        SectionIndex(0)
+    }
+
+    /// Reserve a section table index.
+    ///
+    /// Automatically also reserves the null section header if required.
+    ///
+    /// This must be called before [`Self::reserve_section_headers`].
+    pub fn reserve_section_index(&mut self) -> SectionIndex {
+        debug_assert_eq!(self.section_offset, 0);
+        if self.section_num == 0 {
+            self.section_num = 1;
+        }
+        let index = self.section_num;
+        self.section_num += 1;
+        SectionIndex(index)
+    }
+
+    fn section_header_size(&self) -> usize {
+        if self.is_64 {
+            mem::size_of::<elf::SectionHeader64<Endianness>>()
+        } else {
+            mem::size_of::<elf::SectionHeader32<Endianness>>()
+        }
+    }
+
+    /// Reserve the range for the section headers.
+    ///
+    /// This function does nothing if no sections were reserved.
+    /// This must be called after [`Self::reserve_section_index`]
+    /// and other functions that reserve section indices.
+    pub fn reserve_section_headers(&mut self) {
+        debug_assert_eq!(self.section_offset, 0);
+        if self.section_num == 0 {
+            return;
+        }
+        self.section_offset = self.reserve(
+            self.section_num as usize * self.section_header_size(),
+            self.elf_align,
+        );
+    }
+
+    /// Write the null section header.
+    ///
+    /// This must be the first section header that is written.
+    /// This function does nothing if no sections were reserved.
+    pub fn write_null_section_header(&mut self) {
+        if self.section_num == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.section_offset, self.buffer.len());
+        self.write_section_header(&SectionHeader {
+            name: None,
+            sh_type: 0,
+            sh_flags: 0,
+            sh_addr: 0,
+            sh_offset: 0,
+            sh_size: if self.section_num >= elf::SHN_LORESERVE.into() {
+                self.section_num.into()
+            } else {
+                0
+            },
+            sh_link: if self.shstrtab_index.0 >= elf::SHN_LORESERVE.into() {
+                self.shstrtab_index.0
+            } else {
+                0
+            },
+            // TODO: e_phnum overflow
+            sh_info: 0,
+            sh_addralign: 0,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Write a section header.
+    pub fn write_section_header(&mut self, section: &SectionHeader) {
+        let sh_name = if let Some(name) = section.name {
+            self.shstrtab.get_offset(name) as u32
+        } else {
+            0
+        };
+        let endian = self.endian;
+        if self.is_64 {
+            let section = elf::SectionHeader64 {
+                sh_name: U32::new(endian, sh_name),
+                sh_type: U32::new(endian, section.sh_type),
+                sh_flags: U64::new(endian, section.sh_flags),
+                sh_addr: U64::new(endian, section.sh_addr),
+                sh_offset: U64::new(endian, section.sh_offset),
+                sh_size: U64::new(endian, section.sh_size),
+                sh_link: U32::new(endian, section.sh_link),
+                sh_info: U32::new(endian, section.sh_info),
+                sh_addralign: U64::new(endian, section.sh_addralign),
+                sh_entsize: U64::new(endian, section.sh_entsize),
+            };
+            self.buffer.write(&section);
+        } else {
+            let section = elf::SectionHeader32 {
+                sh_name: U32::new(endian, sh_name),
+                sh_type: U32::new(endian, section.sh_type),
+                sh_flags: U32::new(endian, section.sh_flags as u32),
+                sh_addr: U32::new(endian, section.sh_addr as u32),
+                sh_offset: U32::new(endian, section.sh_offset as u32),
+                sh_size: U32::new(endian, section.sh_size as u32),
+                sh_link: U32::new(endian, section.sh_link),
+                sh_info: U32::new(endian, section.sh_info),
+                sh_addralign: U32::new(endian, section.sh_addralign as u32),
+                sh_entsize: U32::new(endian, section.sh_entsize as u32),
+            };
+            self.buffer.write(&section);
+        }
+    }
+
+    /// Add a section name to the section header string table.
+    ///
+    /// This will be stored in the `.shstrtab` section.
+    ///
+    /// This must be called before [`Self::reserve_shstrtab`].
+    pub fn add_section_name(&mut self, name: &'a [u8]) -> StringId {
+        debug_assert_eq!(self.shstrtab_offset, 0);
+        self.shstrtab.add(name)
+    }
+
+    /// Reserve the range for the section header string table.
+    ///
+    /// This range is used for a section named `.shstrtab`.
+    ///
+    /// This function does nothing if no sections were reserved.
+    /// This must be called after [`Self::add_section_name`].
+    /// and other functions that reserve section names and indices.
+    pub fn reserve_shstrtab(&mut self) {
+        debug_assert_eq!(self.shstrtab_offset, 0);
+        if self.section_num == 0 {
+            return;
+        }
+        // Start with null section name.
+        self.shstrtab_data = vec![0];
+        self.shstrtab.write(1, &mut self.shstrtab_data);
+        self.shstrtab_offset = self.reserve(self.shstrtab_data.len(), 1);
+    }
+
+    /// Write the section header string table.
+    ///
+    /// This function does nothing if the section was not reserved.
+    pub fn write_shstrtab(&mut self) {
+        if self.shstrtab_offset == 0 {
+            return;
+        }
+        debug_assert_eq!(self.shstrtab_offset, self.buffer.len());
+        self.buffer.write_bytes(&self.shstrtab_data);
+    }
+
+    /// Reserve the section index for the section header string table.
+    ///
+    /// This must be called before [`Self::reserve_shstrtab`]
+    /// and [`Self::reserve_section_headers`].
+    pub fn reserve_shstrtab_section_index(&mut self) -> SectionIndex {
+        debug_assert_eq!(self.shstrtab_index, SectionIndex(0));
+        self.shstrtab_str_id = Some(self.add_section_name(&b".shstrtab"[..]));
+        self.shstrtab_index = self.reserve_section_index();
+        self.shstrtab_index
+    }
+
+    /// Write the section header for the section header string table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_shstrtab_section_header(&mut self) {
+        if self.shstrtab_index == SectionIndex(0) {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.shstrtab_str_id,
+            sh_type: elf::SHT_STRTAB,
+            sh_flags: 0,
+            sh_addr: 0,
+            sh_offset: self.shstrtab_offset as u64,
+            sh_size: self.shstrtab_data.len() as u64,
+            sh_link: 0,
+            sh_info: 0,
+            sh_addralign: 1,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Add a string to the string table.
+    ///
+    /// This will be stored in the `.strtab` section.
+    ///
+    /// This must be called before [`Self::reserve_strtab`].
+    pub fn add_string(&mut self, name: &'a [u8]) -> StringId {
+        debug_assert_eq!(self.strtab_offset, 0);
+        self.need_strtab = true;
+        self.strtab.add(name)
+    }
+
+    /// Return true if `.strtab` is needed.
+    pub fn strtab_needed(&self) -> bool {
+        self.need_strtab
+    }
+
+    /// Reserve the range for the string table.
+    ///
+    /// This range is used for a section named `.strtab`.
+    ///
+    /// This function does nothing if no strings or symbols were defined.
+    /// This must be called after [`Self::add_string`].
+    pub fn reserve_strtab(&mut self) {
+        debug_assert_eq!(self.strtab_offset, 0);
+        if !self.need_strtab {
+            return;
+        }
+        // Start with null string.
+        self.strtab_data = vec![0];
+        self.strtab.write(1, &mut self.strtab_data);
+        self.strtab_offset = self.reserve(self.strtab_data.len(), 1);
+    }
+
+    /// Write the string table.
+    ///
+    /// This function does nothing if the section was not reserved.
+    pub fn write_strtab(&mut self) {
+        if self.strtab_offset == 0 {
+            return;
+        }
+        debug_assert_eq!(self.strtab_offset, self.buffer.len());
+        self.buffer.write_bytes(&self.strtab_data);
+    }
+
+    /// Reserve the section index for the string table.
+    ///
+    /// This must be called before [`Self::reserve_section_headers`].
+    pub fn reserve_strtab_section_index(&mut self) -> SectionIndex {
+        debug_assert_eq!(self.strtab_index, SectionIndex(0));
+        self.strtab_str_id = Some(self.add_section_name(&b".strtab"[..]));
+        self.strtab_index = self.reserve_section_index();
+        self.strtab_index
+    }
+
+    /// Write the section header for the string table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_strtab_section_header(&mut self) {
+        if self.strtab_index == SectionIndex(0) {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.strtab_str_id,
+            sh_type: elf::SHT_STRTAB,
+            sh_flags: 0,
+            sh_addr: 0,
+            sh_offset: self.strtab_offset as u64,
+            sh_size: self.strtab_data.len() as u64,
+            sh_link: 0,
+            sh_info: 0,
+            sh_addralign: 1,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Reserve the null symbol table entry.
+    ///
+    /// This will be stored in the `.symtab` section.
+    ///
+    /// The null symbol table entry is usually automatically reserved,
+    /// but this can be used to force an empty symbol table.
+    ///
+    /// This must be called before [`Self::reserve_symtab`].
+    pub fn reserve_null_symbol_index(&mut self) -> SymbolIndex {
+        debug_assert_eq!(self.symtab_offset, 0);
+        debug_assert_eq!(self.symtab_num, 0);
+        self.symtab_num = 1;
+        // The symtab must link to a strtab.
+        self.need_strtab = true;
+        SymbolIndex(0)
+    }
+
+    /// Reserve a symbol table entry.
+    ///
+    /// This will be stored in the `.symtab` section.
+    ///
+    /// `section_index` is used to determine whether `.symtab_shndx` is required.
+    ///
+    /// Automatically also reserves the null symbol if required.
+    /// Callers may assume that the returned indices will be sequential
+    /// starting at 1.
+    ///
+    /// This must be called before [`Self::reserve_symtab`] and
+    /// [`Self::reserve_symtab_shndx`].
+    pub fn reserve_symbol_index(&mut self, section_index: Option<SectionIndex>) -> SymbolIndex {
+        debug_assert_eq!(self.symtab_offset, 0);
+        debug_assert_eq!(self.symtab_shndx_offset, 0);
+        if self.symtab_num == 0 {
+            self.symtab_num = 1;
+            // The symtab must link to a strtab.
+            self.need_strtab = true;
+        }
+        let index = self.symtab_num;
+        self.symtab_num += 1;
+        if let Some(section_index) = section_index {
+            if section_index.0 >= elf::SHN_LORESERVE.into() {
+                self.need_symtab_shndx = true;
+            }
+        }
+        SymbolIndex(index)
+    }
+
+    /// Return the number of reserved symbol table entries.
+    ///
+    /// Includes the null symbol.
+    pub fn symbol_count(&self) -> u32 {
+        self.symtab_num
+    }
+
+    fn symbol_size(&self) -> usize {
+        if self.is_64 {
+            mem::size_of::<elf::Sym64<Endianness>>()
+        } else {
+            mem::size_of::<elf::Sym32<Endianness>>()
+        }
+    }
+
+    /// Reserve the range for the symbol table.
+    ///
+    /// This range is used for a section named `.symtab`.
+    /// This function does nothing if no symbols were reserved.
+    /// This must be called after [`Self::reserve_symbol_index`].
+    pub fn reserve_symtab(&mut self) {
+        debug_assert_eq!(self.symtab_offset, 0);
+        if self.symtab_num == 0 {
+            return;
+        }
+        self.symtab_offset = self.reserve(
+            self.symtab_num as usize * self.symbol_size(),
+            self.elf_align,
+        );
+    }
+
+    /// Write the null symbol.
+    ///
+    /// This must be the first symbol that is written.
+    /// This function does nothing if no symbols were reserved.
+    pub fn write_null_symbol(&mut self) {
+        if self.symtab_num == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.symtab_offset, self.buffer.len());
+        if self.is_64 {
+            self.buffer.write(&elf::Sym64::<Endianness>::default());
+        } else {
+            self.buffer.write(&elf::Sym32::<Endianness>::default());
+        }
+
+        if self.need_symtab_shndx {
+            self.symtab_shndx_data.write_pod(&U32::new(self.endian, 0));
+        }
+    }
+
+    /// Write a symbol.
+    pub fn write_symbol(&mut self, sym: &Sym) {
+        let st_name = if let Some(name) = sym.name {
+            self.strtab.get_offset(name) as u32
+        } else {
+            0
+        };
+        let st_shndx = if let Some(section) = sym.section {
+            if section.0 >= elf::SHN_LORESERVE as u32 {
+                elf::SHN_XINDEX
+            } else {
+                section.0 as u16
+            }
+        } else {
+            sym.st_shndx
+        };
+
+        let endian = self.endian;
+        if self.is_64 {
+            let sym = elf::Sym64 {
+                st_name: U32::new(endian, st_name),
+                st_info: sym.st_info,
+                st_other: sym.st_other,
+                st_shndx: U16::new(endian, st_shndx),
+                st_value: U64::new(endian, sym.st_value),
+                st_size: U64::new(endian, sym.st_size),
+            };
+            self.buffer.write(&sym);
+        } else {
+            let sym = elf::Sym32 {
+                st_name: U32::new(endian, st_name),
+                st_info: sym.st_info,
+                st_other: sym.st_other,
+                st_shndx: U16::new(endian, st_shndx),
+                st_value: U32::new(endian, sym.st_value as u32),
+                st_size: U32::new(endian, sym.st_size as u32),
+            };
+            self.buffer.write(&sym);
+        }
+
+        if self.need_symtab_shndx {
+            let section_index = sym.section.unwrap_or(SectionIndex(0));
+            self.symtab_shndx_data
+                .write_pod(&U32::new(self.endian, section_index.0));
+        }
+    }
+
+    /// Reserve the section index for the symbol table.
+    ///
+    /// This must be called before [`Self::reserve_section_headers`].
+    pub fn reserve_symtab_section_index(&mut self) -> SectionIndex {
+        debug_assert_eq!(self.symtab_index, SectionIndex(0));
+        self.symtab_str_id = Some(self.add_section_name(&b".symtab"[..]));
+        self.symtab_index = self.reserve_section_index();
+        self.symtab_index
+    }
+
+    /// Return the section index of the symbol table.
+    pub fn symtab_index(&mut self) -> SectionIndex {
+        self.symtab_index
+    }
+
+    /// Write the section header for the symbol table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_symtab_section_header(&mut self, num_local: u32) {
+        if self.symtab_index == SectionIndex(0) {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.symtab_str_id,
+            sh_type: elf::SHT_SYMTAB,
+            sh_flags: 0,
+            sh_addr: 0,
+            sh_offset: self.symtab_offset as u64,
+            sh_size: self.symtab_num as u64 * self.symbol_size() as u64,
+            sh_link: self.strtab_index.0,
+            sh_info: num_local,
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: self.symbol_size() as u64,
+        });
+    }
+
+    /// Return true if `.symtab_shndx` is needed.
+    pub fn symtab_shndx_needed(&self) -> bool {
+        self.need_symtab_shndx
+    }
+
+    /// Reserve the range for the extended section indices for the symbol table.
+    ///
+    /// This range is used for a section named `.symtab_shndx`.
+    /// This also reserves a section index.
+    ///
+    /// This function does nothing if extended section indices are not needed.
+    /// This must be called after [`Self::reserve_symbol_index`].
+    pub fn reserve_symtab_shndx(&mut self) {
+        debug_assert_eq!(self.symtab_shndx_offset, 0);
+        if !self.need_symtab_shndx {
+            return;
+        }
+        self.symtab_shndx_offset = self.reserve(self.symtab_num as usize * 4, 4);
+        self.symtab_shndx_data.reserve(self.symtab_num as usize * 4);
+    }
+
+    /// Write the extended section indices for the symbol table.
+    ///
+    /// This function does nothing if the section was not reserved.
+    pub fn write_symtab_shndx(&mut self) {
+        if self.symtab_shndx_offset == 0 {
+            return;
+        }
+        debug_assert_eq!(self.symtab_shndx_offset, self.buffer.len());
+        debug_assert_eq!(self.symtab_num as usize * 4, self.symtab_shndx_data.len());
+        self.buffer.write_bytes(&self.symtab_shndx_data);
+    }
+
+    /// Reserve the section index for the extended section indices symbol table.
+    ///
+    /// You should check [`Self::symtab_shndx_needed`] before calling this
+    /// unless you have other means of knowing if this section is needed.
+    ///
+    /// This must be called before [`Self::reserve_section_headers`].
+    pub fn reserve_symtab_shndx_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.symtab_shndx_str_id.is_none());
+        self.symtab_shndx_str_id = Some(self.add_section_name(&b".symtab_shndx"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Write the section header for the extended section indices for the symbol table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_symtab_shndx_section_header(&mut self) {
+        if self.symtab_shndx_str_id.is_none() {
+            return;
+        }
+        let sh_size = if self.symtab_shndx_offset == 0 {
+            0
+        } else {
+            (self.symtab_num * 4) as u64
+        };
+        self.write_section_header(&SectionHeader {
+            name: self.symtab_shndx_str_id,
+            sh_type: elf::SHT_SYMTAB_SHNDX,
+            sh_flags: 0,
+            sh_addr: 0,
+            sh_offset: self.symtab_shndx_offset as u64,
+            sh_size,
+            sh_link: self.symtab_index.0,
+            sh_info: 0,
+            sh_addralign: 4,
+            sh_entsize: 4,
+        });
+    }
+
+    /// Add a string to the dynamic string table.
+    ///
+    /// This will be stored in the `.dynstr` section.
+    ///
+    /// This must be called before [`Self::reserve_dynstr`].
+    pub fn add_dynamic_string(&mut self, name: &'a [u8]) -> StringId {
+        debug_assert_eq!(self.dynstr_offset, 0);
+        self.need_dynstr = true;
+        self.dynstr.add(name)
+    }
+
+    /// Get a string that was previously added to the dynamic string table.
+    ///
+    /// Panics if the string was not added.
+    pub fn get_dynamic_string(&self, name: &'a [u8]) -> StringId {
+        self.dynstr.get_id(name)
+    }
+
+    /// Return true if `.dynstr` is needed.
+    pub fn dynstr_needed(&self) -> bool {
+        self.need_dynstr
+    }
+
+    /// Reserve the range for the dynamic string table.
+    ///
+    /// This range is used for a section named `.dynstr`.
+    ///
+    /// This function does nothing if no dynamic strings or symbols were defined.
+    /// This must be called after [`Self::add_dynamic_string`].
+    pub fn reserve_dynstr(&mut self) {
+        debug_assert_eq!(self.dynstr_offset, 0);
+        if !self.need_dynstr {
+            return;
+        }
+        // Start with null string.
+        self.dynstr_data = vec![0];
+        self.dynstr.write(1, &mut self.dynstr_data);
+        self.dynstr_offset = self.reserve(self.dynstr_data.len(), 1);
+    }
+
+    /// Write the dynamic string table.
+    ///
+    /// This function does nothing if the section was not reserved.
+    pub fn write_dynstr(&mut self) {
+        if self.dynstr_offset == 0 {
+            return;
+        }
+        debug_assert_eq!(self.dynstr_offset, self.buffer.len());
+        self.buffer.write_bytes(&self.dynstr_data);
+    }
+
+    /// Reserve the section index for the dynamic string table.
+    ///
+    /// This must be called before [`Self::reserve_section_headers`].
+    pub fn reserve_dynstr_section_index(&mut self) -> SectionIndex {
+        debug_assert_eq!(self.dynstr_index, SectionIndex(0));
+        self.dynstr_str_id = Some(self.add_section_name(&b".dynstr"[..]));
+        self.dynstr_index = self.reserve_section_index();
+        self.dynstr_index
+    }
+
+    /// Return the section index of the dynamic string table.
+    pub fn dynstr_index(&mut self) -> SectionIndex {
+        self.dynstr_index
+    }
+
+    /// Write the section header for the dynamic string table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_dynstr_section_header(&mut self, sh_addr: u64) {
+        if self.dynstr_index == SectionIndex(0) {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.dynstr_str_id,
+            sh_type: elf::SHT_STRTAB,
+            sh_flags: elf::SHF_ALLOC.into(),
+            sh_addr,
+            sh_offset: self.dynstr_offset as u64,
+            sh_size: self.dynstr_data.len() as u64,
+            sh_link: 0,
+            sh_info: 0,
+            sh_addralign: 1,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Reserve the null dynamic symbol table entry.
+    ///
+    /// This will be stored in the `.dynsym` section.
+    ///
+    /// The null dynamic symbol table entry is usually automatically reserved,
+    /// but this can be used to force an empty dynamic symbol table.
+    ///
+    /// This must be called before [`Self::reserve_dynsym`].
+    pub fn reserve_null_dynamic_symbol_index(&mut self) -> SymbolIndex {
+        debug_assert_eq!(self.dynsym_offset, 0);
+        debug_assert_eq!(self.dynsym_num, 0);
+        self.dynsym_num = 1;
+        // The symtab must link to a strtab.
+        self.need_dynstr = true;
+        SymbolIndex(0)
+    }
+
+    /// Reserve a dynamic symbol table entry.
+    ///
+    /// This will be stored in the `.dynsym` section.
+    ///
+    /// Automatically also reserves the null symbol if required.
+    /// Callers may assume that the returned indices will be sequential
+    /// starting at 1.
+    ///
+    /// This must be called before [`Self::reserve_dynsym`].
+    pub fn reserve_dynamic_symbol_index(&mut self) -> SymbolIndex {
+        debug_assert_eq!(self.dynsym_offset, 0);
+        if self.dynsym_num == 0 {
+            self.dynsym_num = 1;
+            // The symtab must link to a strtab.
+            self.need_dynstr = true;
+        }
+        let index = self.dynsym_num;
+        self.dynsym_num += 1;
+        SymbolIndex(index)
+    }
+
+    /// Return the number of reserved dynamic symbols.
+    ///
+    /// Includes the null symbol.
+    pub fn dynamic_symbol_count(&mut self) -> u32 {
+        self.dynsym_num
+    }
+
+    /// Reserve the range for the dynamic symbol table.
+    ///
+    /// This range is used for a section named `.dynsym`.
+    ///
+    /// This function does nothing if no dynamic symbols were reserved.
+    /// This must be called after [`Self::reserve_dynamic_symbol_index`].
+    pub fn reserve_dynsym(&mut self) {
+        debug_assert_eq!(self.dynsym_offset, 0);
+        if self.dynsym_num == 0 {
+            return;
+        }
+        self.dynsym_offset = self.reserve(
+            self.dynsym_num as usize * self.symbol_size(),
+            self.elf_align,
+        );
+    }
+
+    /// Write the null dynamic symbol.
+    ///
+    /// This must be the first dynamic symbol that is written.
+    /// This function does nothing if no dynamic symbols were reserved.
+    pub fn write_null_dynamic_symbol(&mut self) {
+        if self.dynsym_num == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.dynsym_offset, self.buffer.len());
+        if self.is_64 {
+            self.buffer.write(&elf::Sym64::<Endianness>::default());
+        } else {
+            self.buffer.write(&elf::Sym32::<Endianness>::default());
+        }
+    }
+
+    /// Write a dynamic symbol.
+    pub fn write_dynamic_symbol(&mut self, sym: &Sym) {
+        let st_name = if let Some(name) = sym.name {
+            self.dynstr.get_offset(name) as u32
+        } else {
+            0
+        };
+
+        let st_shndx = if let Some(section) = sym.section {
+            if section.0 >= elf::SHN_LORESERVE as u32 {
+                // TODO: we don't actually write out .dynsym_shndx yet.
+                // This is unlikely to be needed though.
+                elf::SHN_XINDEX
+            } else {
+                section.0 as u16
+            }
+        } else {
+            sym.st_shndx
+        };
+
+        let endian = self.endian;
+        if self.is_64 {
+            let sym = elf::Sym64 {
+                st_name: U32::new(endian, st_name),
+                st_info: sym.st_info,
+                st_other: sym.st_other,
+                st_shndx: U16::new(endian, st_shndx),
+                st_value: U64::new(endian, sym.st_value),
+                st_size: U64::new(endian, sym.st_size),
+            };
+            self.buffer.write(&sym);
+        } else {
+            let sym = elf::Sym32 {
+                st_name: U32::new(endian, st_name),
+                st_info: sym.st_info,
+                st_other: sym.st_other,
+                st_shndx: U16::new(endian, st_shndx),
+                st_value: U32::new(endian, sym.st_value as u32),
+                st_size: U32::new(endian, sym.st_size as u32),
+            };
+            self.buffer.write(&sym);
+        }
+    }
+
+    /// Reserve the section index for the dynamic symbol table.
+    ///
+    /// This must be called before [`Self::reserve_section_headers`].
+    pub fn reserve_dynsym_section_index(&mut self) -> SectionIndex {
+        debug_assert_eq!(self.dynsym_index, SectionIndex(0));
+        self.dynsym_str_id = Some(self.add_section_name(&b".dynsym"[..]));
+        self.dynsym_index = self.reserve_section_index();
+        self.dynsym_index
+    }
+
+    /// Return the section index of the dynamic symbol table.
+    pub fn dynsym_index(&mut self) -> SectionIndex {
+        self.dynsym_index
+    }
+
+    /// Write the section header for the dynamic symbol table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_dynsym_section_header(&mut self, sh_addr: u64, num_local: u32) {
+        if self.dynsym_index == SectionIndex(0) {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.dynsym_str_id,
+            sh_type: elf::SHT_DYNSYM,
+            sh_flags: elf::SHF_ALLOC.into(),
+            sh_addr,
+            sh_offset: self.dynsym_offset as u64,
+            sh_size: self.dynsym_num as u64 * self.symbol_size() as u64,
+            sh_link: self.dynstr_index.0,
+            sh_info: num_local,
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: self.symbol_size() as u64,
+        });
+    }
+
+    fn dyn_size(&self) -> usize {
+        if self.is_64 {
+            mem::size_of::<elf::Dyn64<Endianness>>()
+        } else {
+            mem::size_of::<elf::Dyn32<Endianness>>()
+        }
+    }
+
+    /// Reserve the range for the `.dynamic` section.
+    ///
+    /// This function does nothing if `dynamic_num` is zero.
+    pub fn reserve_dynamic(&mut self, dynamic_num: usize) {
+        debug_assert_eq!(self.dynamic_offset, 0);
+        if dynamic_num == 0 {
+            return;
+        }
+        self.dynamic_num = dynamic_num;
+        self.dynamic_offset = self.reserve(dynamic_num * self.dyn_size(), self.elf_align);
+    }
+
+    /// Write alignment padding bytes prior to the `.dynamic` section.
+    ///
+    /// This function does nothing if the section was not reserved.
+    pub fn write_align_dynamic(&mut self) {
+        if self.dynamic_offset == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.dynamic_offset, self.buffer.len());
+    }
+
+    /// Write a dynamic string entry.
+    pub fn write_dynamic_string(&mut self, tag: u32, id: StringId) {
+        self.write_dynamic(tag, self.dynstr.get_offset(id) as u64);
+    }
+
+    /// Write a dynamic value entry.
+    pub fn write_dynamic(&mut self, d_tag: u32, d_val: u64) {
+        debug_assert!(self.dynamic_offset <= self.buffer.len());
+        let endian = self.endian;
+        if self.is_64 {
+            let d = elf::Dyn64 {
+                d_tag: U64::new(endian, d_tag.into()),
+                d_val: U64::new(endian, d_val),
+            };
+            self.buffer.write(&d);
+        } else {
+            let d = elf::Dyn32 {
+                d_tag: U32::new(endian, d_tag),
+                d_val: U32::new(endian, d_val as u32),
+            };
+            self.buffer.write(&d);
+        }
+        debug_assert!(
+            self.dynamic_offset + self.dynamic_num * self.dyn_size() >= self.buffer.len()
+        );
+    }
+
+    /// Reserve the section index for the dynamic table.
+    pub fn reserve_dynamic_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.dynamic_str_id.is_none());
+        self.dynamic_str_id = Some(self.add_section_name(&b".dynamic"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Write the section header for the dynamic table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_dynamic_section_header(&mut self, sh_addr: u64) {
+        if self.dynamic_str_id.is_none() {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.dynamic_str_id,
+            sh_type: elf::SHT_DYNAMIC,
+            sh_flags: (elf::SHF_WRITE | elf::SHF_ALLOC).into(),
+            sh_addr,
+            sh_offset: self.dynamic_offset as u64,
+            sh_size: (self.dynamic_num * self.dyn_size()) as u64,
+            sh_link: self.dynstr_index.0,
+            sh_info: 0,
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: self.dyn_size() as u64,
+        });
+    }
+
+    fn rel_size(&self, is_rela: bool) -> usize {
+        if self.is_64 {
+            if is_rela {
+                mem::size_of::<elf::Rela64<Endianness>>()
+            } else {
+                mem::size_of::<elf::Rel64<Endianness>>()
+            }
+        } else {
+            if is_rela {
+                mem::size_of::<elf::Rela32<Endianness>>()
+            } else {
+                mem::size_of::<elf::Rel32<Endianness>>()
+            }
+        }
+    }
+
+    /// Reserve a file range for a SysV hash section.
+    ///
+    /// `symbol_count` is the number of symbols in the hash,
+    /// not the total number of symbols.
+    pub fn reserve_hash(&mut self, bucket_count: u32, chain_count: u32) {
+        self.hash_size = mem::size_of::<elf::HashHeader<Endianness>>()
+            + bucket_count as usize * 4
+            + chain_count as usize * 4;
+        self.hash_offset = self.reserve(self.hash_size, self.elf_align);
+    }
+
+    /// Write a SysV hash section.
+    ///
+    /// `chain_count` is the number of symbols in the hash.
+    /// The argument to `hash` will be in the range `0..chain_count`.
+    pub fn write_hash<F>(&mut self, bucket_count: u32, chain_count: u32, hash: F)
+    where
+        F: Fn(u32) -> Option<u32>,
+    {
+        let mut buckets = vec![U32::new(self.endian, 0); bucket_count as usize];
+        let mut chains = vec![U32::new(self.endian, 0); chain_count as usize];
+        for i in 0..chain_count {
+            if let Some(hash) = hash(i) {
+                let bucket = hash % bucket_count;
+                chains[i as usize] = buckets[bucket as usize];
+                buckets[bucket as usize] = U32::new(self.endian, i);
+            }
+        }
+
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.hash_offset, self.buffer.len());
+        self.buffer.write(&elf::HashHeader {
+            bucket_count: U32::new(self.endian, bucket_count),
+            chain_count: U32::new(self.endian, chain_count),
+        });
+        self.buffer.write_slice(&buckets);
+        self.buffer.write_slice(&chains);
+    }
+
+    /// Reserve the section index for the SysV hash table.
+    pub fn reserve_hash_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.hash_str_id.is_none());
+        self.hash_str_id = Some(self.add_section_name(&b".hash"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Write the section header for the SysV hash table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_hash_section_header(&mut self, sh_addr: u64) {
+        if self.hash_str_id.is_none() {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.hash_str_id,
+            sh_type: elf::SHT_HASH,
+            sh_flags: elf::SHF_ALLOC.into(),
+            sh_addr,
+            sh_offset: self.hash_offset as u64,
+            sh_size: self.hash_size as u64,
+            sh_link: self.dynsym_index.0,
+            sh_info: 0,
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: 4,
+        });
+    }
+
+    /// Reserve a file range for a GNU hash section.
+    ///
+    /// `symbol_count` is the number of symbols in the hash,
+    /// not the total number of symbols.
+    pub fn reserve_gnu_hash(&mut self, bloom_count: u32, bucket_count: u32, symbol_count: u32) {
+        self.gnu_hash_size = mem::size_of::<elf::GnuHashHeader<Endianness>>()
+            + bloom_count as usize * self.elf_align
+            + bucket_count as usize * 4
+            + symbol_count as usize * 4;
+        self.gnu_hash_offset = self.reserve(self.gnu_hash_size, self.elf_align);
+    }
+
+    /// Write a GNU hash section.
+    ///
+    /// `symbol_count` is the number of symbols in the hash.
+    /// The argument to `hash` will be in the range `0..symbol_count`.
+    ///
+    /// This requires that symbols are already sorted by bucket.
+    pub fn write_gnu_hash<F>(
+        &mut self,
+        symbol_base: u32,
+        bloom_shift: u32,
+        bloom_count: u32,
+        bucket_count: u32,
+        symbol_count: u32,
+        hash: F,
+    ) where
+        F: Fn(u32) -> u32,
+    {
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.gnu_hash_offset, self.buffer.len());
+        self.buffer.write(&elf::GnuHashHeader {
+            bucket_count: U32::new(self.endian, bucket_count),
+            symbol_base: U32::new(self.endian, symbol_base),
+            bloom_count: U32::new(self.endian, bloom_count),
+            bloom_shift: U32::new(self.endian, bloom_shift),
+        });
+
+        // Calculate and write bloom filter.
+        if self.is_64 {
+            let mut bloom_filters = vec![0; bloom_count as usize];
+            for i in 0..symbol_count {
+                let h = hash(i);
+                bloom_filters[((h / 64) & (bloom_count - 1)) as usize] |=
+                    1 << (h % 64) | 1 << ((h >> bloom_shift) % 64);
+            }
+            for bloom_filter in bloom_filters {
+                self.buffer.write(&U64::new(self.endian, bloom_filter));
+            }
+        } else {
+            let mut bloom_filters = vec![0; bloom_count as usize];
+            for i in 0..symbol_count {
+                let h = hash(i);
+                bloom_filters[((h / 32) & (bloom_count - 1)) as usize] |=
+                    1 << (h % 32) | 1 << ((h >> bloom_shift) % 32);
+            }
+            for bloom_filter in bloom_filters {
+                self.buffer.write(&U32::new(self.endian, bloom_filter));
+            }
+        }
+
+        // Write buckets.
+        //
+        // This requires that symbols are already sorted by bucket.
+        let mut bucket = 0;
+        for i in 0..symbol_count {
+            let symbol_bucket = hash(i) % bucket_count;
+            while bucket < symbol_bucket {
+                self.buffer.write(&U32::new(self.endian, 0));
+                bucket += 1;
+            }
+            if bucket == symbol_bucket {
+                self.buffer.write(&U32::new(self.endian, symbol_base + i));
+                bucket += 1;
+            }
+        }
+        while bucket < bucket_count {
+            self.buffer.write(&U32::new(self.endian, 0));
+            bucket += 1;
+        }
+
+        // Write hash values.
+        for i in 0..symbol_count {
+            let mut h = hash(i);
+            if i == symbol_count - 1 || h % bucket_count != hash(i + 1) % bucket_count {
+                h |= 1;
+            } else {
+                h &= !1;
+            }
+            self.buffer.write(&U32::new(self.endian, h));
+        }
+    }
+
+    /// Reserve the section index for the GNU hash table.
+    pub fn reserve_gnu_hash_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.gnu_hash_str_id.is_none());
+        self.gnu_hash_str_id = Some(self.add_section_name(&b".gnu.hash"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Write the section header for the GNU hash table.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_gnu_hash_section_header(&mut self, sh_addr: u64) {
+        if self.gnu_hash_str_id.is_none() {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.gnu_hash_str_id,
+            sh_type: elf::SHT_GNU_HASH,
+            sh_flags: elf::SHF_ALLOC.into(),
+            sh_addr,
+            sh_offset: self.gnu_hash_offset as u64,
+            sh_size: self.gnu_hash_size as u64,
+            sh_link: self.dynsym_index.0,
+            sh_info: 0,
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Reserve the range for the `.gnu.version` section.
+    ///
+    /// This function does nothing if no dynamic symbols were reserved.
+    pub fn reserve_gnu_versym(&mut self) {
+        debug_assert_eq!(self.gnu_versym_offset, 0);
+        if self.dynsym_num == 0 {
+            return;
+        }
+        self.gnu_versym_offset = self.reserve(self.dynsym_num as usize * 2, 2);
+    }
+
+    /// Write the null symbol version entry.
+    ///
+    /// This must be the first symbol version that is written.
+    /// This function does nothing if no dynamic symbols were reserved.
+    pub fn write_null_gnu_versym(&mut self) {
+        if self.dynsym_num == 0 {
+            return;
+        }
+        util::write_align(self.buffer, 2);
+        debug_assert_eq!(self.gnu_versym_offset, self.buffer.len());
+        self.write_gnu_versym(0);
+    }
+
+    /// Write a symbol version entry.
+    pub fn write_gnu_versym(&mut self, versym: u16) {
+        self.buffer.write(&U16::new(self.endian, versym));
+    }
+
+    /// Reserve the section index for the `.gnu.version` section.
+    pub fn reserve_gnu_versym_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.gnu_versym_str_id.is_none());
+        self.gnu_versym_str_id = Some(self.add_section_name(&b".gnu.version"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Write the section header for the `.gnu.version` section.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_gnu_versym_section_header(&mut self, sh_addr: u64) {
+        if self.gnu_versym_str_id.is_none() {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.gnu_versym_str_id,
+            sh_type: elf::SHT_GNU_VERSYM,
+            sh_flags: elf::SHF_ALLOC.into(),
+            sh_addr,
+            sh_offset: self.gnu_versym_offset as u64,
+            sh_size: self.dynsym_num as u64 * 2,
+            sh_link: self.dynsym_index.0,
+            sh_info: 0,
+            sh_addralign: 2,
+            sh_entsize: 2,
+        });
+    }
+
+    /// Reserve the range for the `.gnu.version_d` section.
+    pub fn reserve_gnu_verdef(&mut self, verdef_count: usize, verdaux_count: usize) {
+        debug_assert_eq!(self.gnu_verdef_offset, 0);
+        if verdef_count == 0 {
+            return;
+        }
+        self.gnu_verdef_size = verdef_count * mem::size_of::<elf::Verdef<Endianness>>()
+            + verdaux_count * mem::size_of::<elf::Verdaux<Endianness>>();
+        self.gnu_verdef_offset = self.reserve(self.gnu_verdef_size, self.elf_align);
+        self.gnu_verdef_count = verdef_count as u16;
+        self.gnu_verdef_remaining = self.gnu_verdef_count;
+    }
+
+    /// Write alignment padding bytes prior to a `.gnu.version_d` section.
+    pub fn write_align_gnu_verdef(&mut self) {
+        if self.gnu_verdef_offset == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.gnu_verdef_offset, self.buffer.len());
+    }
+
+    /// Write a version definition entry.
+    pub fn write_gnu_verdef(&mut self, verdef: &Verdef) {
+        debug_assert_ne!(self.gnu_verdef_remaining, 0);
+        self.gnu_verdef_remaining -= 1;
+        let vd_next = if self.gnu_verdef_remaining == 0 {
+            0
+        } else {
+            mem::size_of::<elf::Verdef<Endianness>>() as u32
+                + verdef.aux_count as u32 * mem::size_of::<elf::Verdaux<Endianness>>() as u32
+        };
+
+        self.gnu_verdaux_remaining = verdef.aux_count;
+        let vd_aux = if verdef.aux_count == 0 {
+            0
+        } else {
+            mem::size_of::<elf::Verdef<Endianness>>() as u32
+        };
+
+        self.buffer.write(&elf::Verdef {
+            vd_version: U16::new(self.endian, verdef.version),
+            vd_flags: U16::new(self.endian, verdef.flags),
+            vd_ndx: U16::new(self.endian, verdef.index),
+            vd_cnt: U16::new(self.endian, verdef.aux_count),
+            vd_hash: U32::new(self.endian, elf::hash(self.dynstr.get_string(verdef.name))),
+            vd_aux: U32::new(self.endian, vd_aux),
+            vd_next: U32::new(self.endian, vd_next),
+        });
+        self.write_gnu_verdaux(verdef.name);
+    }
+
+    /// Write a version definition auxiliary entry.
+    pub fn write_gnu_verdaux(&mut self, name: StringId) {
+        debug_assert_ne!(self.gnu_verdaux_remaining, 0);
+        self.gnu_verdaux_remaining -= 1;
+        let vda_next = if self.gnu_verdaux_remaining == 0 {
+            0
+        } else {
+            mem::size_of::<elf::Verdaux<Endianness>>() as u32
+        };
+        self.buffer.write(&elf::Verdaux {
+            vda_name: U32::new(self.endian, self.dynstr.get_offset(name) as u32),
+            vda_next: U32::new(self.endian, vda_next),
+        });
+    }
+
+    /// Reserve the section index for the `.gnu.version_d` section.
+    pub fn reserve_gnu_verdef_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.gnu_verdef_str_id.is_none());
+        self.gnu_verdef_str_id = Some(self.add_section_name(&b".gnu.version_d"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Write the section header for the `.gnu.version_d` section.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_gnu_verdef_section_header(&mut self, sh_addr: u64) {
+        if self.gnu_verdef_str_id.is_none() {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.gnu_verdef_str_id,
+            sh_type: elf::SHT_GNU_VERDEF,
+            sh_flags: elf::SHF_ALLOC.into(),
+            sh_addr,
+            sh_offset: self.gnu_verdef_offset as u64,
+            sh_size: self.gnu_verdef_size as u64,
+            sh_link: self.dynstr_index.0,
+            sh_info: self.gnu_verdef_count.into(),
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Reserve the range for the `.gnu.version_r` section.
+    pub fn reserve_gnu_verneed(&mut self, verneed_count: usize, vernaux_count: usize) {
+        debug_assert_eq!(self.gnu_verneed_offset, 0);
+        if verneed_count == 0 {
+            return;
+        }
+        self.gnu_verneed_size = verneed_count * mem::size_of::<elf::Verneed<Endianness>>()
+            + vernaux_count * mem::size_of::<elf::Vernaux<Endianness>>();
+        self.gnu_verneed_offset = self.reserve(self.gnu_verneed_size, self.elf_align);
+        self.gnu_verneed_count = verneed_count as u16;
+        self.gnu_verneed_remaining = self.gnu_verneed_count;
+    }
+
+    /// Write alignment padding bytes prior to a `.gnu.version_r` section.
+    pub fn write_align_gnu_verneed(&mut self) {
+        if self.gnu_verneed_offset == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.gnu_verneed_offset, self.buffer.len());
+    }
+
+    /// Write a version need entry.
+    pub fn write_gnu_verneed(&mut self, verneed: &Verneed) {
+        debug_assert_ne!(self.gnu_verneed_remaining, 0);
+        self.gnu_verneed_remaining -= 1;
+        let vn_next = if self.gnu_verneed_remaining == 0 {
+            0
+        } else {
+            mem::size_of::<elf::Verneed<Endianness>>() as u32
+                + verneed.aux_count as u32 * mem::size_of::<elf::Vernaux<Endianness>>() as u32
+        };
+
+        self.gnu_vernaux_remaining = verneed.aux_count;
+        let vn_aux = if verneed.aux_count == 0 {
+            0
+        } else {
+            mem::size_of::<elf::Verneed<Endianness>>() as u32
+        };
+
+        self.buffer.write(&elf::Verneed {
+            vn_version: U16::new(self.endian, verneed.version),
+            vn_cnt: U16::new(self.endian, verneed.aux_count),
+            vn_file: U32::new(self.endian, self.dynstr.get_offset(verneed.file) as u32),
+            vn_aux: U32::new(self.endian, vn_aux),
+            vn_next: U32::new(self.endian, vn_next),
+        });
+    }
+
+    /// Write a version need auxiliary entry.
+    pub fn write_gnu_vernaux(&mut self, vernaux: &Vernaux) {
+        debug_assert_ne!(self.gnu_vernaux_remaining, 0);
+        self.gnu_vernaux_remaining -= 1;
+        let vna_next = if self.gnu_vernaux_remaining == 0 {
+            0
+        } else {
+            mem::size_of::<elf::Vernaux<Endianness>>() as u32
+        };
+        self.buffer.write(&elf::Vernaux {
+            vna_hash: U32::new(self.endian, elf::hash(self.dynstr.get_string(vernaux.name))),
+            vna_flags: U16::new(self.endian, vernaux.flags),
+            vna_other: U16::new(self.endian, vernaux.index),
+            vna_name: U32::new(self.endian, self.dynstr.get_offset(vernaux.name) as u32),
+            vna_next: U32::new(self.endian, vna_next),
+        });
+    }
+
+    /// Reserve the section index for the `.gnu.version_r` section.
+    pub fn reserve_gnu_verneed_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.gnu_verneed_str_id.is_none());
+        self.gnu_verneed_str_id = Some(self.add_section_name(&b".gnu.version_r"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Write the section header for the `.gnu.version_r` section.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_gnu_verneed_section_header(&mut self, sh_addr: u64) {
+        if self.gnu_verneed_str_id.is_none() {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.gnu_verneed_str_id,
+            sh_type: elf::SHT_GNU_VERNEED,
+            sh_flags: elf::SHF_ALLOC.into(),
+            sh_addr,
+            sh_offset: self.gnu_verneed_offset as u64,
+            sh_size: self.gnu_verneed_size as u64,
+            sh_link: self.dynstr_index.0,
+            sh_info: self.gnu_verneed_count.into(),
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Reserve the section index for the `.gnu.attributes` section.
+    pub fn reserve_gnu_attributes_section_index(&mut self) -> SectionIndex {
+        debug_assert!(self.gnu_attributes_str_id.is_none());
+        self.gnu_attributes_str_id = Some(self.add_section_name(&b".gnu.attributes"[..]));
+        self.reserve_section_index()
+    }
+
+    /// Reserve the range for the `.gnu.attributes` section.
+    pub fn reserve_gnu_attributes(&mut self, gnu_attributes_size: usize) {
+        debug_assert_eq!(self.gnu_attributes_offset, 0);
+        if gnu_attributes_size == 0 {
+            return;
+        }
+        self.gnu_attributes_size = gnu_attributes_size;
+        self.gnu_attributes_offset = self.reserve(self.gnu_attributes_size, self.elf_align);
+    }
+
+    /// Write the section header for the `.gnu.attributes` section.
+    ///
+    /// This function does nothing if the section index was not reserved.
+    pub fn write_gnu_attributes_section_header(&mut self) {
+        if self.gnu_attributes_str_id.is_none() {
+            return;
+        }
+        self.write_section_header(&SectionHeader {
+            name: self.gnu_attributes_str_id,
+            sh_type: elf::SHT_GNU_ATTRIBUTES,
+            sh_flags: 0,
+            sh_addr: 0,
+            sh_offset: self.gnu_attributes_offset as u64,
+            sh_size: self.gnu_attributes_size as u64,
+            sh_link: self.dynstr_index.0,
+            sh_info: 0, // TODO
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: 0,
+        });
+    }
+
+    /// Write the data for the `.gnu.attributes` section.
+    pub fn write_gnu_attributes(&mut self, data: &[u8]) {
+        if self.gnu_attributes_offset == 0 {
+            return;
+        }
+        util::write_align(self.buffer, self.elf_align);
+        debug_assert_eq!(self.gnu_attributes_offset, self.buffer.len());
+        self.buffer.write_bytes(data);
+    }
+
+    /// Reserve a file range for the given number of relocations.
+    ///
+    /// Returns the offset of the range.
+    pub fn reserve_relocations(&mut self, count: usize, is_rela: bool) -> usize {
+        self.reserve(count * self.rel_size(is_rela), self.elf_align)
+    }
+
+    /// Write alignment padding bytes prior to a relocation section.
+    pub fn write_align_relocation(&mut self) {
+        util::write_align(self.buffer, self.elf_align);
+    }
+
+    /// Write a relocation.
+    pub fn write_relocation(&mut self, is_rela: bool, rel: &Rel) {
+        let endian = self.endian;
+        if self.is_64 {
+            if is_rela {
+                let rel = elf::Rela64 {
+                    r_offset: U64::new(endian, rel.r_offset),
+                    r_info: elf::Rela64::r_info(endian, self.is_mips64el, rel.r_sym, rel.r_type),
+                    r_addend: I64::new(endian, rel.r_addend),
+                };
+                self.buffer.write(&rel);
+            } else {
+                let rel = elf::Rel64 {
+                    r_offset: U64::new(endian, rel.r_offset),
+                    r_info: elf::Rel64::r_info(endian, rel.r_sym, rel.r_type),
+                };
+                self.buffer.write(&rel);
+            }
+        } else {
+            if is_rela {
+                let rel = elf::Rela32 {
+                    r_offset: U32::new(endian, rel.r_offset as u32),
+                    r_info: elf::Rel32::r_info(endian, rel.r_sym, rel.r_type as u8),
+                    r_addend: I32::new(endian, rel.r_addend as i32),
+                };
+                self.buffer.write(&rel);
+            } else {
+                let rel = elf::Rel32 {
+                    r_offset: U32::new(endian, rel.r_offset as u32),
+                    r_info: elf::Rel32::r_info(endian, rel.r_sym, rel.r_type as u8),
+                };
+                self.buffer.write(&rel);
+            }
+        }
+    }
+
+    /// Write the section header for a relocation section.
+    ///
+    /// `section` is the index of the section the relocations apply to,
+    /// or 0 if none.
+    ///
+    /// `symtab` is the index of the symbol table the relocations refer to,
+    /// or 0 if none.
+    ///
+    /// `offset` is the file offset of the relocations.
+    pub fn write_relocation_section_header(
+        &mut self,
+        name: StringId,
+        section: SectionIndex,
+        symtab: SectionIndex,
+        offset: usize,
+        count: usize,
+        is_rela: bool,
+    ) {
+        self.write_section_header(&SectionHeader {
+            name: Some(name),
+            sh_type: if is_rela { elf::SHT_RELA } else { elf::SHT_REL },
+            sh_flags: elf::SHF_INFO_LINK.into(),
+            sh_addr: 0,
+            sh_offset: offset as u64,
+            sh_size: (count * self.rel_size(is_rela)) as u64,
+            sh_link: symtab.0,
+            sh_info: section.0,
+            sh_addralign: self.elf_align as u64,
+            sh_entsize: self.rel_size(is_rela) as u64,
+        });
+    }
+
+    /// Reserve a file range for a COMDAT section.
+    ///
+    /// `count` is the number of sections in the COMDAT group.
+    ///
+    /// Returns the offset of the range.
+    pub fn reserve_comdat(&mut self, count: usize) -> usize {
+        self.reserve((count + 1) * 4, 4)
+    }
+
+    /// Write `GRP_COMDAT` at the start of the COMDAT section.
+    pub fn write_comdat_header(&mut self) {
+        util::write_align(self.buffer, 4);
+        self.buffer.write(&U32::new(self.endian, elf::GRP_COMDAT));
+    }
+
+    /// Write an entry in a COMDAT section.
+    pub fn write_comdat_entry(&mut self, entry: SectionIndex) {
+        self.buffer.write(&U32::new(self.endian, entry.0));
+    }
+
+    /// Write the section header for a COMDAT section.
+    pub fn write_comdat_section_header(
+        &mut self,
+        name: StringId,
+        symtab: SectionIndex,
+        symbol: SymbolIndex,
+        offset: usize,
+        count: usize,
+    ) {
+        self.write_section_header(&SectionHeader {
+            name: Some(name),
+            sh_type: elf::SHT_GROUP,
+            sh_flags: 0,
+            sh_addr: 0,
+            sh_offset: offset as u64,
+            sh_size: ((count + 1) * 4) as u64,
+            sh_link: symtab.0,
+            sh_info: symbol.0,
+            sh_addralign: 4,
+            sh_entsize: 4,
+        });
+    }
+
+    /// Return a helper for writing an attributes section.
+    pub fn attributes_writer(&self) -> AttributesWriter {
+        AttributesWriter::new(self.endian)
+    }
+}
+
+/// A helper for writing an attributes section.
+///
+/// Attributes have a variable length encoding, so it is awkward to write them in a
+/// single pass. Instead, we build the entire attributes section data in memory, using
+/// placeholders for unknown lengths that are filled in later.
+#[allow(missing_debug_implementations)]
+pub struct AttributesWriter {
+    endian: Endianness,
+    data: Vec<u8>,
+    subsection_offset: usize,
+    subsubsection_offset: usize,
+}
+
+impl AttributesWriter {
+    /// Create a new `AttributesWriter` for the given endianness.
+    pub fn new(endian: Endianness) -> Self {
+        AttributesWriter {
+            endian,
+            data: vec![0x41],
+            subsection_offset: 0,
+            subsubsection_offset: 0,
+        }
+    }
+
+    /// Start a new subsection with the given vendor name.
+    pub fn start_subsection(&mut self, vendor: &[u8]) {
+        debug_assert_eq!(self.subsection_offset, 0);
+        debug_assert_eq!(self.subsubsection_offset, 0);
+        self.subsection_offset = self.data.len();
+        self.data.extend_from_slice(&[0; 4]);
+        self.data.extend_from_slice(vendor);
+        self.data.push(0);
+    }
+
+    /// End the subsection.
+    ///
+    /// The subsection length is automatically calculated and written.
+    pub fn end_subsection(&mut self) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_eq!(self.subsubsection_offset, 0);
+        let length = self.data.len() - self.subsection_offset;
+        self.data[self.subsection_offset..][..4]
+            .copy_from_slice(pod::bytes_of(&U32::new(self.endian, length as u32)));
+        self.subsection_offset = 0;
+    }
+
+    /// Start a new sub-subsection with the given tag.
+    pub fn start_subsubsection(&mut self, tag: u8) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_eq!(self.subsubsection_offset, 0);
+        self.subsubsection_offset = self.data.len();
+        self.data.push(tag);
+        self.data.extend_from_slice(&[0; 4]);
+    }
+
+    /// Write a section or symbol index to the sub-subsection.
+    ///
+    /// The user must also call this function to write the terminating 0 index.
+    pub fn write_subsubsection_index(&mut self, index: u32) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_ne!(self.subsubsection_offset, 0);
+        util::write_uleb128(&mut self.data, u64::from(index));
+    }
+
+    /// Write raw index data to the sub-subsection.
+    ///
+    /// The terminating 0 index is automatically written.
+    pub fn write_subsubsection_indices(&mut self, indices: &[u8]) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_ne!(self.subsubsection_offset, 0);
+        self.data.extend_from_slice(indices);
+        self.data.push(0);
+    }
+
+    /// Write an attribute tag to the sub-subsection.
+    pub fn write_attribute_tag(&mut self, tag: u64) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_ne!(self.subsubsection_offset, 0);
+        util::write_uleb128(&mut self.data, tag);
+    }
+
+    /// Write an attribute integer value to the sub-subsection.
+    pub fn write_attribute_integer(&mut self, value: u64) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_ne!(self.subsubsection_offset, 0);
+        util::write_uleb128(&mut self.data, value);
+    }
+
+    /// Write an attribute string value to the sub-subsection.
+    ///
+    /// The value must not include the null terminator.
+    pub fn write_attribute_string(&mut self, value: &[u8]) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_ne!(self.subsubsection_offset, 0);
+        self.data.extend_from_slice(value);
+        self.data.push(0);
+    }
+
+    /// Write raw attribute data to the sub-subsection.
+    pub fn write_subsubsection_attributes(&mut self, attributes: &[u8]) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_ne!(self.subsubsection_offset, 0);
+        self.data.extend_from_slice(attributes);
+    }
+
+    /// End the sub-subsection.
+    ///
+    /// The sub-subsection length is automatically calculated and written.
+    pub fn end_subsubsection(&mut self) {
+        debug_assert_ne!(self.subsection_offset, 0);
+        debug_assert_ne!(self.subsubsection_offset, 0);
+        let length = self.data.len() - self.subsubsection_offset;
+        self.data[self.subsubsection_offset + 1..][..4]
+            .copy_from_slice(pod::bytes_of(&U32::new(self.endian, length as u32)));
+        self.subsubsection_offset = 0;
+    }
+
+    /// Return the completed section data.
+    pub fn data(self) -> Vec<u8> {
+        debug_assert_eq!(self.subsection_offset, 0);
+        debug_assert_eq!(self.subsubsection_offset, 0);
+        self.data
+    }
+}
+
+/// Native endian version of [`elf::FileHeader64`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct FileHeader {
+    pub os_abi: u8,
+    pub abi_version: u8,
+    pub e_type: u16,
+    pub e_machine: u16,
+    pub e_entry: u64,
+    pub e_flags: u32,
+}
+
+/// Native endian version of [`elf::ProgramHeader64`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct ProgramHeader {
+    pub p_type: u32,
+    pub p_flags: u32,
+    pub p_offset: u64,
+    pub p_vaddr: u64,
+    pub p_paddr: u64,
+    pub p_filesz: u64,
+    pub p_memsz: u64,
+    pub p_align: u64,
+}
+
+/// Native endian version of [`elf::SectionHeader64`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct SectionHeader {
+    pub name: Option<StringId>,
+    pub sh_type: u32,
+    pub sh_flags: u64,
+    pub sh_addr: u64,
+    pub sh_offset: u64,
+    pub sh_size: u64,
+    pub sh_link: u32,
+    pub sh_info: u32,
+    pub sh_addralign: u64,
+    pub sh_entsize: u64,
+}
+
+/// Native endian version of [`elf::Sym64`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct Sym {
+    pub name: Option<StringId>,
+    pub section: Option<SectionIndex>,
+    pub st_info: u8,
+    pub st_other: u8,
+    pub st_shndx: u16,
+    pub st_value: u64,
+    pub st_size: u64,
+}
+
+/// Unified native endian version of [`elf::Rel64`] and [`elf::Rela64`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct Rel {
+    pub r_offset: u64,
+    pub r_sym: u32,
+    pub r_type: u32,
+    pub r_addend: i64,
+}
+
+/// Information required for writing [`elf::Verdef`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct Verdef {
+    pub version: u16,
+    pub flags: u16,
+    pub index: u16,
+    pub aux_count: u16,
+    /// The name for the first [`elf::Verdaux`] entry.
+    pub name: StringId,
+}
+
+/// Information required for writing [`elf::Verneed`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct Verneed {
+    pub version: u16,
+    pub aux_count: u16,
+    pub file: StringId,
+}
+
+/// Information required for writing [`elf::Vernaux`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct Vernaux {
+    pub flags: u16,
+    pub index: u16,
+    pub name: StringId,
+}
diff --git a/vendor/object/src/write/macho.rs b/vendor/object/src/write/macho.rs
new file mode 100644
index 0000000..1c61523
--- /dev/null
+++ b/vendor/object/src/write/macho.rs
@@ -0,0 +1,1095 @@
+use core::mem;
+
+use crate::endian::*;
+use crate::macho;
+use crate::write::string::*;
+use crate::write::util::*;
+use crate::write::*;
+use crate::AddressSize;
+
+#[derive(Default, Clone, Copy)]
+struct SectionOffsets {
+    index: usize,
+    offset: usize,
+    address: u64,
+    reloc_offset: usize,
+    reloc_count: usize,
+}
+
+#[derive(Default, Clone, Copy)]
+struct SymbolOffsets {
+    index: usize,
+    str_id: Option<StringId>,
+}
+
+/// The customizable portion of a [`macho::BuildVersionCommand`].
+#[derive(Debug, Default, Clone, Copy)]
+#[non_exhaustive] // May want to add the tool list?
+pub struct MachOBuildVersion {
+    /// One of the `PLATFORM_` constants (for example,
+    /// [`object::macho::PLATFORM_MACOS`](macho::PLATFORM_MACOS)).
+    pub platform: u32,
+    /// The minimum OS version, where `X.Y.Z` is encoded in nibbles as
+    /// `xxxx.yy.zz`.
+    pub minos: u32,
+    /// The SDK version as `X.Y.Z`, where `X.Y.Z` is encoded in nibbles as
+    /// `xxxx.yy.zz`.
+    pub sdk: u32,
+}
+
+impl MachOBuildVersion {
+    fn cmdsize(&self) -> u32 {
+        // Same size for both endianness, and we don't have `ntools`.
+        let sz = mem::size_of::<macho::BuildVersionCommand<Endianness>>();
+        debug_assert!(sz <= u32::MAX as usize);
+        sz as u32
+    }
+}
+
+// Public methods.
+impl<'a> Object<'a> {
+    /// Specify the Mach-O CPU subtype.
+    ///
+    /// Requires `feature = "macho"`.
+    #[inline]
+    pub fn set_macho_cpu_subtype(&mut self, cpu_subtype: u32) {
+        self.macho_cpu_subtype = Some(cpu_subtype);
+    }
+
+    /// Specify information for a Mach-O `LC_BUILD_VERSION` command.
+    ///
+    /// Requires `feature = "macho"`.
+    #[inline]
+    pub fn set_macho_build_version(&mut self, info: MachOBuildVersion) {
+        self.macho_build_version = Some(info);
+    }
+}
+
+// Private methods.
+impl<'a> Object<'a> {
+    pub(crate) fn macho_set_subsections_via_symbols(&mut self) {
+        let flags = match self.flags {
+            FileFlags::MachO { flags } => flags,
+            _ => 0,
+        };
+        self.flags = FileFlags::MachO {
+            flags: flags | macho::MH_SUBSECTIONS_VIA_SYMBOLS,
+        };
+    }
+
+    pub(crate) fn macho_segment_name(&self, segment: StandardSegment) -> &'static [u8] {
+        match segment {
+            StandardSegment::Text => &b"__TEXT"[..],
+            StandardSegment::Data => &b"__DATA"[..],
+            StandardSegment::Debug => &b"__DWARF"[..],
+        }
+    }
+
+    pub(crate) fn macho_section_info(
+        &self,
+        section: StandardSection,
+    ) -> (&'static [u8], &'static [u8], SectionKind, SectionFlags) {
+        match section {
+            StandardSection::Text => (
+                &b"__TEXT"[..],
+                &b"__text"[..],
+                SectionKind::Text,
+                SectionFlags::None,
+            ),
+            StandardSection::Data => (
+                &b"__DATA"[..],
+                &b"__data"[..],
+                SectionKind::Data,
+                SectionFlags::None,
+            ),
+            StandardSection::ReadOnlyData => (
+                &b"__TEXT"[..],
+                &b"__const"[..],
+                SectionKind::ReadOnlyData,
+                SectionFlags::None,
+            ),
+            StandardSection::ReadOnlyDataWithRel => (
+                &b"__DATA"[..],
+                &b"__const"[..],
+                SectionKind::ReadOnlyDataWithRel,
+                SectionFlags::None,
+            ),
+            StandardSection::ReadOnlyString => (
+                &b"__TEXT"[..],
+                &b"__cstring"[..],
+                SectionKind::ReadOnlyString,
+                SectionFlags::None,
+            ),
+            StandardSection::UninitializedData => (
+                &b"__DATA"[..],
+                &b"__bss"[..],
+                SectionKind::UninitializedData,
+                SectionFlags::None,
+            ),
+            StandardSection::Tls => (
+                &b"__DATA"[..],
+                &b"__thread_data"[..],
+                SectionKind::Tls,
+                SectionFlags::None,
+            ),
+            StandardSection::UninitializedTls => (
+                &b"__DATA"[..],
+                &b"__thread_bss"[..],
+                SectionKind::UninitializedTls,
+                SectionFlags::None,
+            ),
+            StandardSection::TlsVariables => (
+                &b"__DATA"[..],
+                &b"__thread_vars"[..],
+                SectionKind::TlsVariables,
+                SectionFlags::None,
+            ),
+            StandardSection::Common => (
+                &b"__DATA"[..],
+                &b"__common"[..],
+                SectionKind::Common,
+                SectionFlags::None,
+            ),
+            StandardSection::GnuProperty => {
+                // Unsupported section.
+                (&[], &[], SectionKind::Note, SectionFlags::None)
+            }
+        }
+    }
+
+    fn macho_tlv_bootstrap(&mut self) -> SymbolId {
+        match self.tlv_bootstrap {
+            Some(id) => id,
+            None => {
+                let id = self.add_symbol(Symbol {
+                    name: b"_tlv_bootstrap".to_vec(),
+                    value: 0,
+                    size: 0,
+                    kind: SymbolKind::Text,
+                    scope: SymbolScope::Dynamic,
+                    weak: false,
+                    section: SymbolSection::Undefined,
+                    flags: SymbolFlags::None,
+                });
+                self.tlv_bootstrap = Some(id);
+                id
+            }
+        }
+    }
+
+    /// Create the `__thread_vars` entry for a TLS variable.
+    ///
+    /// The symbol given by `symbol_id` will be updated to point to this entry.
+    ///
+    /// A new `SymbolId` will be returned. The caller must update this symbol
+    /// to point to the initializer.
+    ///
+    /// If `symbol_id` is not for a TLS variable, then it is returned unchanged.
+    pub(crate) fn macho_add_thread_var(&mut self, symbol_id: SymbolId) -> SymbolId {
+        let symbol = self.symbol_mut(symbol_id);
+        if symbol.kind != SymbolKind::Tls {
+            return symbol_id;
+        }
+
+        // Create the initializer symbol.
+        let mut name = symbol.name.clone();
+        name.extend_from_slice(b"$tlv$init");
+        let init_symbol_id = self.add_raw_symbol(Symbol {
+            name,
+            value: 0,
+            size: 0,
+            kind: SymbolKind::Tls,
+            scope: SymbolScope::Compilation,
+            weak: false,
+            section: SymbolSection::Undefined,
+            flags: SymbolFlags::None,
+        });
+
+        // Add the tlv entry.
+        // Three pointers in size:
+        //   - __tlv_bootstrap - used to make sure support exists
+        //   - spare pointer - used when mapped by the runtime
+        //   - pointer to symbol initializer
+        let section = self.section_id(StandardSection::TlsVariables);
+        let address_size = self.architecture.address_size().unwrap().bytes();
+        let size = u64::from(address_size) * 3;
+        let data = vec![0; size as usize];
+        let offset = self.append_section_data(section, &data, u64::from(address_size));
+
+        let tlv_bootstrap = self.macho_tlv_bootstrap();
+        self.add_relocation(
+            section,
+            Relocation {
+                offset,
+                size: address_size * 8,
+                kind: RelocationKind::Absolute,
+                encoding: RelocationEncoding::Generic,
+                symbol: tlv_bootstrap,
+                addend: 0,
+            },
+        )
+        .unwrap();
+        self.add_relocation(
+            section,
+            Relocation {
+                offset: offset + u64::from(address_size) * 2,
+                size: address_size * 8,
+                kind: RelocationKind::Absolute,
+                encoding: RelocationEncoding::Generic,
+                symbol: init_symbol_id,
+                addend: 0,
+            },
+        )
+        .unwrap();
+
+        // Update the symbol to point to the tlv.
+        let symbol = self.symbol_mut(symbol_id);
+        symbol.value = offset;
+        symbol.size = size;
+        symbol.section = SymbolSection::Section(section);
+
+        init_symbol_id
+    }
+
+    pub(crate) fn macho_fixup_relocation(&mut self, relocation: &mut Relocation) -> i64 {
+        let relative = match relocation.kind {
+            RelocationKind::Relative
+            | RelocationKind::GotRelative
+            | RelocationKind::PltRelative
+            | RelocationKind::MachO { relative: true, .. } => true,
+            _ => false,
+        };
+        if relative {
+            // For PC relative relocations on some architectures, the
+            // addend does not include the offset required due to the
+            // PC being different from the place of the relocation.
+            // This differs from other file formats, so adjust the
+            // addend here to account for this.
+            let pcrel_offset = match self.architecture {
+                Architecture::I386 => 4,
+                Architecture::X86_64 => match relocation.kind {
+                    RelocationKind::MachO {
+                        value: macho::X86_64_RELOC_SIGNED_1,
+                        ..
+                    } => 5,
+                    RelocationKind::MachO {
+                        value: macho::X86_64_RELOC_SIGNED_2,
+                        ..
+                    } => 6,
+                    RelocationKind::MachO {
+                        value: macho::X86_64_RELOC_SIGNED_4,
+                        ..
+                    } => 8,
+                    _ => 4,
+                },
+                // TODO: maybe missing support for some architectures and relocations
+                _ => 0,
+            };
+            relocation.addend += pcrel_offset;
+        }
+        // Aarch64 relocs of these sizes act as if they are double-word length
+        if self.architecture == Architecture::Aarch64 && matches!(relocation.size, 12 | 21 | 26) {
+            relocation.size = 32;
+        }
+        // Check for relocations that use an explicit addend.
+        if self.architecture == Architecture::Aarch64 {
+            if relocation.encoding == RelocationEncoding::AArch64Call {
+                return 0;
+            }
+            if let RelocationKind::MachO { value, .. } = relocation.kind {
+                match value {
+                    macho::ARM64_RELOC_BRANCH26
+                    | macho::ARM64_RELOC_PAGE21
+                    | macho::ARM64_RELOC_PAGEOFF12 => return 0,
+                    _ => {}
+                }
+            }
+        }
+        // Signify implicit addend.
+        let constant = relocation.addend;
+        relocation.addend = 0;
+        constant
+    }
+
+    pub(crate) fn macho_write(&self, buffer: &mut dyn WritableBuffer) -> Result<()> {
+        let address_size = self.architecture.address_size().unwrap();
+        let endian = self.endian;
+        let macho32 = MachO32 { endian };
+        let macho64 = MachO64 { endian };
+        let macho: &dyn MachO = match address_size {
+            AddressSize::U8 | AddressSize::U16 | AddressSize::U32 => &macho32,
+            AddressSize::U64 => &macho64,
+        };
+        let pointer_align = address_size.bytes() as usize;
+
+        // Calculate offsets of everything, and build strtab.
+        let mut offset = 0;
+
+        // Calculate size of Mach-O header.
+        offset += macho.mach_header_size();
+
+        // Calculate size of commands.
+        let mut ncmds = 0;
+        let command_offset = offset;
+
+        // Calculate size of segment command and section headers.
+        let segment_command_offset = offset;
+        let segment_command_len =
+            macho.segment_command_size() + self.sections.len() * macho.section_header_size();
+        offset += segment_command_len;
+        ncmds += 1;
+
+        // Calculate size of build version.
+        let build_version_offset = offset;
+        if let Some(version) = &self.macho_build_version {
+            offset += version.cmdsize() as usize;
+            ncmds += 1;
+        }
+
+        // Calculate size of symtab command.
+        let symtab_command_offset = offset;
+        let symtab_command_len = mem::size_of::<macho::SymtabCommand<Endianness>>();
+        offset += symtab_command_len;
+        ncmds += 1;
+
+        // Calculate size of dysymtab command.
+        let dysymtab_command_offset = offset;
+        let dysymtab_command_len = mem::size_of::<macho::DysymtabCommand<Endianness>>();
+        offset += dysymtab_command_len;
+        ncmds += 1;
+
+        let sizeofcmds = offset - command_offset;
+
+        // Calculate size of section data.
+        // Section data can immediately follow the load commands without any alignment padding.
+        let segment_file_offset = offset;
+        let mut section_offsets = vec![SectionOffsets::default(); self.sections.len()];
+        let mut address = 0;
+        for (index, section) in self.sections.iter().enumerate() {
+            section_offsets[index].index = 1 + index;
+            if !section.is_bss() {
+                address = align_u64(address, section.align);
+                section_offsets[index].address = address;
+                section_offsets[index].offset = segment_file_offset + address as usize;
+                address += section.size;
+            }
+        }
+        let segment_file_size = address as usize;
+        offset += address as usize;
+        for (index, section) in self.sections.iter().enumerate() {
+            if section.is_bss() {
+                debug_assert!(section.data.is_empty());
+                address = align_u64(address, section.align);
+                section_offsets[index].address = address;
+                address += section.size;
+            }
+        }
+
+        // Partition symbols and add symbol strings to strtab.
+        let mut strtab = StringTable::default();
+        let mut symbol_offsets = vec![SymbolOffsets::default(); self.symbols.len()];
+        let mut local_symbols = vec![];
+        let mut external_symbols = vec![];
+        let mut undefined_symbols = vec![];
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            // The unified API allows creating symbols that we don't emit, so filter
+            // them out here.
+            //
+            // Since we don't actually emit the symbol kind, we validate it here too.
+            match symbol.kind {
+                SymbolKind::Text | SymbolKind::Data | SymbolKind::Tls | SymbolKind::Unknown => {}
+                SymbolKind::File | SymbolKind::Section => continue,
+                SymbolKind::Null | SymbolKind::Label => {
+                    return Err(Error(format!(
+                        "unimplemented symbol `{}` kind {:?}",
+                        symbol.name().unwrap_or(""),
+                        symbol.kind
+                    )));
+                }
+            }
+            if !symbol.name.is_empty() {
+                symbol_offsets[index].str_id = Some(strtab.add(&symbol.name));
+            }
+            if symbol.is_undefined() {
+                undefined_symbols.push(index);
+            } else if symbol.is_local() {
+                local_symbols.push(index);
+            } else {
+                external_symbols.push(index);
+            }
+        }
+
+        external_symbols.sort_by_key(|index| &*self.symbols[*index].name);
+        undefined_symbols.sort_by_key(|index| &*self.symbols[*index].name);
+
+        // Count symbols.
+        let mut nsyms = 0;
+        for index in local_symbols
+            .iter()
+            .copied()
+            .chain(external_symbols.iter().copied())
+            .chain(undefined_symbols.iter().copied())
+        {
+            symbol_offsets[index].index = nsyms;
+            nsyms += 1;
+        }
+
+        // Calculate size of relocations.
+        for (index, section) in self.sections.iter().enumerate() {
+            let count: usize = section
+                .relocations
+                .iter()
+                .map(|reloc| 1 + usize::from(reloc.addend != 0))
+                .sum();
+            if count != 0 {
+                offset = align(offset, pointer_align);
+                section_offsets[index].reloc_offset = offset;
+                section_offsets[index].reloc_count = count;
+                let len = count * mem::size_of::<macho::Relocation<Endianness>>();
+                offset += len;
+            }
+        }
+
+        // Calculate size of symtab.
+        offset = align(offset, pointer_align);
+        let symtab_offset = offset;
+        let symtab_len = nsyms * macho.nlist_size();
+        offset += symtab_len;
+
+        // Calculate size of strtab.
+        let strtab_offset = offset;
+        // Start with null name.
+        let mut strtab_data = vec![0];
+        strtab.write(1, &mut strtab_data);
+        write_align(&mut strtab_data, pointer_align);
+        offset += strtab_data.len();
+
+        // Start writing.
+        buffer
+            .reserve(offset)
+            .map_err(|_| Error(String::from("Cannot allocate buffer")))?;
+
+        // Write file header.
+        let (cputype, mut cpusubtype) = match (self.architecture, self.sub_architecture) {
+            (Architecture::Arm, None) => (macho::CPU_TYPE_ARM, macho::CPU_SUBTYPE_ARM_ALL),
+            (Architecture::Aarch64, None) => (macho::CPU_TYPE_ARM64, macho::CPU_SUBTYPE_ARM64_ALL),
+            (Architecture::Aarch64, Some(SubArchitecture::Arm64E)) => {
+                (macho::CPU_TYPE_ARM64, macho::CPU_SUBTYPE_ARM64E)
+            }
+            (Architecture::Aarch64_Ilp32, None) => {
+                (macho::CPU_TYPE_ARM64_32, macho::CPU_SUBTYPE_ARM64_32_V8)
+            }
+            (Architecture::I386, None) => (macho::CPU_TYPE_X86, macho::CPU_SUBTYPE_I386_ALL),
+            (Architecture::X86_64, None) => (macho::CPU_TYPE_X86_64, macho::CPU_SUBTYPE_X86_64_ALL),
+            (Architecture::PowerPc, None) => {
+                (macho::CPU_TYPE_POWERPC, macho::CPU_SUBTYPE_POWERPC_ALL)
+            }
+            (Architecture::PowerPc64, None) => {
+                (macho::CPU_TYPE_POWERPC64, macho::CPU_SUBTYPE_POWERPC_ALL)
+            }
+            _ => {
+                return Err(Error(format!(
+                    "unimplemented architecture {:?} with sub-architecture {:?}",
+                    self.architecture, self.sub_architecture
+                )));
+            }
+        };
+
+        if let Some(cpu_subtype) = self.macho_cpu_subtype {
+            cpusubtype = cpu_subtype;
+        }
+
+        let flags = match self.flags {
+            FileFlags::MachO { flags } => flags,
+            _ => 0,
+        };
+        macho.write_mach_header(
+            buffer,
+            MachHeader {
+                cputype,
+                cpusubtype,
+                filetype: macho::MH_OBJECT,
+                ncmds,
+                sizeofcmds: sizeofcmds as u32,
+                flags,
+            },
+        );
+
+        // Write segment command.
+        debug_assert_eq!(segment_command_offset, buffer.len());
+        macho.write_segment_command(
+            buffer,
+            SegmentCommand {
+                cmdsize: segment_command_len as u32,
+                segname: [0; 16],
+                vmaddr: 0,
+                vmsize: address,
+                fileoff: segment_file_offset as u64,
+                filesize: segment_file_size as u64,
+                maxprot: macho::VM_PROT_READ | macho::VM_PROT_WRITE | macho::VM_PROT_EXECUTE,
+                initprot: macho::VM_PROT_READ | macho::VM_PROT_WRITE | macho::VM_PROT_EXECUTE,
+                nsects: self.sections.len() as u32,
+                flags: 0,
+            },
+        );
+
+        // Write section headers.
+        for (index, section) in self.sections.iter().enumerate() {
+            let mut sectname = [0; 16];
+            sectname
+                .get_mut(..section.name.len())
+                .ok_or_else(|| {
+                    Error(format!(
+                        "section name `{}` is too long",
+                        section.name().unwrap_or(""),
+                    ))
+                })?
+                .copy_from_slice(&section.name);
+            let mut segname = [0; 16];
+            segname
+                .get_mut(..section.segment.len())
+                .ok_or_else(|| {
+                    Error(format!(
+                        "segment name `{}` is too long",
+                        section.segment().unwrap_or(""),
+                    ))
+                })?
+                .copy_from_slice(&section.segment);
+            let flags = if let SectionFlags::MachO { flags } = section.flags {
+                flags
+            } else {
+                match section.kind {
+                    SectionKind::Text => {
+                        macho::S_ATTR_PURE_INSTRUCTIONS | macho::S_ATTR_SOME_INSTRUCTIONS
+                    }
+                    SectionKind::Data => 0,
+                    SectionKind::ReadOnlyData | SectionKind::ReadOnlyDataWithRel => 0,
+                    SectionKind::ReadOnlyString => macho::S_CSTRING_LITERALS,
+                    SectionKind::UninitializedData | SectionKind::Common => macho::S_ZEROFILL,
+                    SectionKind::Tls => macho::S_THREAD_LOCAL_REGULAR,
+                    SectionKind::UninitializedTls => macho::S_THREAD_LOCAL_ZEROFILL,
+                    SectionKind::TlsVariables => macho::S_THREAD_LOCAL_VARIABLES,
+                    SectionKind::Debug => macho::S_ATTR_DEBUG,
+                    SectionKind::OtherString => macho::S_CSTRING_LITERALS,
+                    SectionKind::Other | SectionKind::Linker | SectionKind::Metadata => 0,
+                    SectionKind::Note | SectionKind::Unknown | SectionKind::Elf(_) => {
+                        return Err(Error(format!(
+                            "unimplemented section `{}` kind {:?}",
+                            section.name().unwrap_or(""),
+                            section.kind
+                        )));
+                    }
+                }
+            };
+            macho.write_section(
+                buffer,
+                SectionHeader {
+                    sectname,
+                    segname,
+                    addr: section_offsets[index].address,
+                    size: section.size,
+                    offset: section_offsets[index].offset as u32,
+                    align: section.align.trailing_zeros(),
+                    reloff: section_offsets[index].reloc_offset as u32,
+                    nreloc: section_offsets[index].reloc_count as u32,
+                    flags,
+                },
+            );
+        }
+
+        // Write build version.
+        if let Some(version) = &self.macho_build_version {
+            debug_assert_eq!(build_version_offset, buffer.len());
+            buffer.write(&macho::BuildVersionCommand {
+                cmd: U32::new(endian, macho::LC_BUILD_VERSION),
+                cmdsize: U32::new(endian, version.cmdsize()),
+                platform: U32::new(endian, version.platform),
+                minos: U32::new(endian, version.minos),
+                sdk: U32::new(endian, version.sdk),
+                ntools: U32::new(endian, 0),
+            });
+        }
+
+        // Write symtab command.
+        debug_assert_eq!(symtab_command_offset, buffer.len());
+        let symtab_command = macho::SymtabCommand {
+            cmd: U32::new(endian, macho::LC_SYMTAB),
+            cmdsize: U32::new(endian, symtab_command_len as u32),
+            symoff: U32::new(endian, symtab_offset as u32),
+            nsyms: U32::new(endian, nsyms as u32),
+            stroff: U32::new(endian, strtab_offset as u32),
+            strsize: U32::new(endian, strtab_data.len() as u32),
+        };
+        buffer.write(&symtab_command);
+
+        // Write dysymtab command.
+        debug_assert_eq!(dysymtab_command_offset, buffer.len());
+        let dysymtab_command = macho::DysymtabCommand {
+            cmd: U32::new(endian, macho::LC_DYSYMTAB),
+            cmdsize: U32::new(endian, dysymtab_command_len as u32),
+            ilocalsym: U32::new(endian, 0),
+            nlocalsym: U32::new(endian, local_symbols.len() as u32),
+            iextdefsym: U32::new(endian, local_symbols.len() as u32),
+            nextdefsym: U32::new(endian, external_symbols.len() as u32),
+            iundefsym: U32::new(
+                endian,
+                local_symbols.len() as u32 + external_symbols.len() as u32,
+            ),
+            nundefsym: U32::new(endian, undefined_symbols.len() as u32),
+            tocoff: U32::default(),
+            ntoc: U32::default(),
+            modtaboff: U32::default(),
+            nmodtab: U32::default(),
+            extrefsymoff: U32::default(),
+            nextrefsyms: U32::default(),
+            indirectsymoff: U32::default(),
+            nindirectsyms: U32::default(),
+            extreloff: U32::default(),
+            nextrel: U32::default(),
+            locreloff: U32::default(),
+            nlocrel: U32::default(),
+        };
+        buffer.write(&dysymtab_command);
+
+        // Write section data.
+        for (index, section) in self.sections.iter().enumerate() {
+            if !section.is_bss() {
+                buffer.resize(section_offsets[index].offset);
+                buffer.write_bytes(&section.data);
+            }
+        }
+        debug_assert_eq!(segment_file_offset + segment_file_size, buffer.len());
+
+        // Write relocations.
+        for (index, section) in self.sections.iter().enumerate() {
+            if !section.relocations.is_empty() {
+                write_align(buffer, pointer_align);
+                debug_assert_eq!(section_offsets[index].reloc_offset, buffer.len());
+                for reloc in &section.relocations {
+                    let r_length = match reloc.size {
+                        8 => 0,
+                        16 => 1,
+                        32 => 2,
+                        64 => 3,
+                        _ => return Err(Error(format!("unimplemented reloc size {:?}", reloc))),
+                    };
+
+                    // Write explicit addend.
+                    if reloc.addend != 0 {
+                        let r_type = match self.architecture {
+                            Architecture::Aarch64 | Architecture::Aarch64_Ilp32 => {
+                                macho::ARM64_RELOC_ADDEND
+                            }
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)))
+                            }
+                        };
+
+                        let reloc_info = macho::RelocationInfo {
+                            r_address: reloc.offset as u32,
+                            r_symbolnum: reloc.addend as u32,
+                            r_pcrel: false,
+                            r_length,
+                            r_extern: false,
+                            r_type,
+                        };
+                        buffer.write(&reloc_info.relocation(endian));
+                    }
+
+                    let r_extern;
+                    let r_symbolnum;
+                    let symbol = &self.symbols[reloc.symbol.0];
+                    if symbol.kind == SymbolKind::Section {
+                        r_symbolnum = section_offsets[symbol.section.id().unwrap().0].index as u32;
+                        r_extern = false;
+                    } else {
+                        r_symbolnum = symbol_offsets[reloc.symbol.0].index as u32;
+                        r_extern = true;
+                    }
+                    let (r_pcrel, r_type) = match self.architecture {
+                        Architecture::I386 => match reloc.kind {
+                            RelocationKind::Absolute => (false, macho::GENERIC_RELOC_VANILLA),
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::X86_64 => match (reloc.kind, reloc.encoding) {
+                            (RelocationKind::Absolute, RelocationEncoding::Generic) => {
+                                (false, macho::X86_64_RELOC_UNSIGNED)
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::Generic) => {
+                                (true, macho::X86_64_RELOC_SIGNED)
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::X86RipRelative) => {
+                                (true, macho::X86_64_RELOC_SIGNED)
+                            }
+                            (RelocationKind::Relative, RelocationEncoding::X86Branch) => {
+                                (true, macho::X86_64_RELOC_BRANCH)
+                            }
+                            (RelocationKind::PltRelative, RelocationEncoding::X86Branch) => {
+                                (true, macho::X86_64_RELOC_BRANCH)
+                            }
+                            (RelocationKind::GotRelative, RelocationEncoding::Generic) => {
+                                (true, macho::X86_64_RELOC_GOT)
+                            }
+                            (
+                                RelocationKind::GotRelative,
+                                RelocationEncoding::X86RipRelativeMovq,
+                            ) => (true, macho::X86_64_RELOC_GOT_LOAD),
+                            (RelocationKind::MachO { value, relative }, _) => (relative, value),
+                            _ => {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        },
+                        Architecture::Aarch64 | Architecture::Aarch64_Ilp32 => {
+                            match (reloc.kind, reloc.encoding) {
+                                (RelocationKind::Absolute, RelocationEncoding::Generic) => {
+                                    (false, macho::ARM64_RELOC_UNSIGNED)
+                                }
+                                (RelocationKind::Relative, RelocationEncoding::AArch64Call) => {
+                                    (true, macho::ARM64_RELOC_BRANCH26)
+                                }
+                                (
+                                    RelocationKind::MachO { value, relative },
+                                    RelocationEncoding::Generic,
+                                ) => (relative, value),
+                                _ => {
+                                    return Err(Error(format!(
+                                        "unimplemented relocation {:?}",
+                                        reloc
+                                    )));
+                                }
+                            }
+                        }
+                        _ => {
+                            if let RelocationKind::MachO { value, relative } = reloc.kind {
+                                (relative, value)
+                            } else {
+                                return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                            }
+                        }
+                    };
+                    let reloc_info = macho::RelocationInfo {
+                        r_address: reloc.offset as u32,
+                        r_symbolnum,
+                        r_pcrel,
+                        r_length,
+                        r_extern,
+                        r_type,
+                    };
+                    buffer.write(&reloc_info.relocation(endian));
+                }
+            }
+        }
+
+        // Write symtab.
+        write_align(buffer, pointer_align);
+        debug_assert_eq!(symtab_offset, buffer.len());
+        for index in local_symbols
+            .iter()
+            .copied()
+            .chain(external_symbols.iter().copied())
+            .chain(undefined_symbols.iter().copied())
+        {
+            let symbol = &self.symbols[index];
+            // TODO: N_STAB
+            let (mut n_type, n_sect) = match symbol.section {
+                SymbolSection::Undefined => (macho::N_UNDF | macho::N_EXT, 0),
+                SymbolSection::Absolute => (macho::N_ABS, 0),
+                SymbolSection::Section(id) => (macho::N_SECT, id.0 + 1),
+                SymbolSection::None | SymbolSection::Common => {
+                    return Err(Error(format!(
+                        "unimplemented symbol `{}` section {:?}",
+                        symbol.name().unwrap_or(""),
+                        symbol.section
+                    )));
+                }
+            };
+            match symbol.scope {
+                SymbolScope::Unknown | SymbolScope::Compilation => {}
+                SymbolScope::Linkage => {
+                    n_type |= macho::N_EXT | macho::N_PEXT;
+                }
+                SymbolScope::Dynamic => {
+                    n_type |= macho::N_EXT;
+                }
+            }
+
+            let n_desc = if let SymbolFlags::MachO { n_desc } = symbol.flags {
+                n_desc
+            } else {
+                let mut n_desc = 0;
+                if symbol.weak {
+                    if symbol.is_undefined() {
+                        n_desc |= macho::N_WEAK_REF;
+                    } else {
+                        n_desc |= macho::N_WEAK_DEF;
+                    }
+                }
+                n_desc
+            };
+
+            let n_value = match symbol.section.id() {
+                Some(section) => section_offsets[section.0].address + symbol.value,
+                None => symbol.value,
+            };
+
+            let n_strx = symbol_offsets[index]
+                .str_id
+                .map(|id| strtab.get_offset(id))
+                .unwrap_or(0);
+
+            macho.write_nlist(
+                buffer,
+                Nlist {
+                    n_strx: n_strx as u32,
+                    n_type,
+                    n_sect: n_sect as u8,
+                    n_desc,
+                    n_value,
+                },
+            );
+        }
+
+        // Write strtab.
+        debug_assert_eq!(strtab_offset, buffer.len());
+        buffer.write_bytes(&strtab_data);
+
+        debug_assert_eq!(offset, buffer.len());
+
+        Ok(())
+    }
+}
+
+struct MachHeader {
+    cputype: u32,
+    cpusubtype: u32,
+    filetype: u32,
+    ncmds: u32,
+    sizeofcmds: u32,
+    flags: u32,
+}
+
+struct SegmentCommand {
+    cmdsize: u32,
+    segname: [u8; 16],
+    vmaddr: u64,
+    vmsize: u64,
+    fileoff: u64,
+    filesize: u64,
+    maxprot: u32,
+    initprot: u32,
+    nsects: u32,
+    flags: u32,
+}
+
+pub struct SectionHeader {
+    sectname: [u8; 16],
+    segname: [u8; 16],
+    addr: u64,
+    size: u64,
+    offset: u32,
+    align: u32,
+    reloff: u32,
+    nreloc: u32,
+    flags: u32,
+}
+
+struct Nlist {
+    n_strx: u32,
+    n_type: u8,
+    n_sect: u8,
+    n_desc: u16,
+    n_value: u64,
+}
+
+trait MachO {
+    fn mach_header_size(&self) -> usize;
+    fn segment_command_size(&self) -> usize;
+    fn section_header_size(&self) -> usize;
+    fn nlist_size(&self) -> usize;
+    fn write_mach_header(&self, buffer: &mut dyn WritableBuffer, section: MachHeader);
+    fn write_segment_command(&self, buffer: &mut dyn WritableBuffer, segment: SegmentCommand);
+    fn write_section(&self, buffer: &mut dyn WritableBuffer, section: SectionHeader);
+    fn write_nlist(&self, buffer: &mut dyn WritableBuffer, nlist: Nlist);
+}
+
+struct MachO32<E> {
+    endian: E,
+}
+
+impl<E: Endian> MachO for MachO32<E> {
+    fn mach_header_size(&self) -> usize {
+        mem::size_of::<macho::MachHeader32<E>>()
+    }
+
+    fn segment_command_size(&self) -> usize {
+        mem::size_of::<macho::SegmentCommand32<E>>()
+    }
+
+    fn section_header_size(&self) -> usize {
+        mem::size_of::<macho::Section32<E>>()
+    }
+
+    fn nlist_size(&self) -> usize {
+        mem::size_of::<macho::Nlist32<E>>()
+    }
+
+    fn write_mach_header(&self, buffer: &mut dyn WritableBuffer, header: MachHeader) {
+        let endian = self.endian;
+        let magic = if endian.is_big_endian() {
+            macho::MH_MAGIC
+        } else {
+            macho::MH_CIGAM
+        };
+        let header = macho::MachHeader32 {
+            magic: U32::new(BigEndian, magic),
+            cputype: U32::new(endian, header.cputype),
+            cpusubtype: U32::new(endian, header.cpusubtype),
+            filetype: U32::new(endian, header.filetype),
+            ncmds: U32::new(endian, header.ncmds),
+            sizeofcmds: U32::new(endian, header.sizeofcmds),
+            flags: U32::new(endian, header.flags),
+        };
+        buffer.write(&header);
+    }
+
+    fn write_segment_command(&self, buffer: &mut dyn WritableBuffer, segment: SegmentCommand) {
+        let endian = self.endian;
+        let segment = macho::SegmentCommand32 {
+            cmd: U32::new(endian, macho::LC_SEGMENT),
+            cmdsize: U32::new(endian, segment.cmdsize),
+            segname: segment.segname,
+            vmaddr: U32::new(endian, segment.vmaddr as u32),
+            vmsize: U32::new(endian, segment.vmsize as u32),
+            fileoff: U32::new(endian, segment.fileoff as u32),
+            filesize: U32::new(endian, segment.filesize as u32),
+            maxprot: U32::new(endian, segment.maxprot),
+            initprot: U32::new(endian, segment.initprot),
+            nsects: U32::new(endian, segment.nsects),
+            flags: U32::new(endian, segment.flags),
+        };
+        buffer.write(&segment);
+    }
+
+    fn write_section(&self, buffer: &mut dyn WritableBuffer, section: SectionHeader) {
+        let endian = self.endian;
+        let section = macho::Section32 {
+            sectname: section.sectname,
+            segname: section.segname,
+            addr: U32::new(endian, section.addr as u32),
+            size: U32::new(endian, section.size as u32),
+            offset: U32::new(endian, section.offset),
+            align: U32::new(endian, section.align),
+            reloff: U32::new(endian, section.reloff),
+            nreloc: U32::new(endian, section.nreloc),
+            flags: U32::new(endian, section.flags),
+            reserved1: U32::default(),
+            reserved2: U32::default(),
+        };
+        buffer.write(&section);
+    }
+
+    fn write_nlist(&self, buffer: &mut dyn WritableBuffer, nlist: Nlist) {
+        let endian = self.endian;
+        let nlist = macho::Nlist32 {
+            n_strx: U32::new(endian, nlist.n_strx),
+            n_type: nlist.n_type,
+            n_sect: nlist.n_sect,
+            n_desc: U16::new(endian, nlist.n_desc),
+            n_value: U32::new(endian, nlist.n_value as u32),
+        };
+        buffer.write(&nlist);
+    }
+}
+
+struct MachO64<E> {
+    endian: E,
+}
+
+impl<E: Endian> MachO for MachO64<E> {
+    fn mach_header_size(&self) -> usize {
+        mem::size_of::<macho::MachHeader64<E>>()
+    }
+
+    fn segment_command_size(&self) -> usize {
+        mem::size_of::<macho::SegmentCommand64<E>>()
+    }
+
+    fn section_header_size(&self) -> usize {
+        mem::size_of::<macho::Section64<E>>()
+    }
+
+    fn nlist_size(&self) -> usize {
+        mem::size_of::<macho::Nlist64<E>>()
+    }
+
+    fn write_mach_header(&self, buffer: &mut dyn WritableBuffer, header: MachHeader) {
+        let endian = self.endian;
+        let magic = if endian.is_big_endian() {
+            macho::MH_MAGIC_64
+        } else {
+            macho::MH_CIGAM_64
+        };
+        let header = macho::MachHeader64 {
+            magic: U32::new(BigEndian, magic),
+            cputype: U32::new(endian, header.cputype),
+            cpusubtype: U32::new(endian, header.cpusubtype),
+            filetype: U32::new(endian, header.filetype),
+            ncmds: U32::new(endian, header.ncmds),
+            sizeofcmds: U32::new(endian, header.sizeofcmds),
+            flags: U32::new(endian, header.flags),
+            reserved: U32::default(),
+        };
+        buffer.write(&header);
+    }
+
+    fn write_segment_command(&self, buffer: &mut dyn WritableBuffer, segment: SegmentCommand) {
+        let endian = self.endian;
+        let segment = macho::SegmentCommand64 {
+            cmd: U32::new(endian, macho::LC_SEGMENT_64),
+            cmdsize: U32::new(endian, segment.cmdsize),
+            segname: segment.segname,
+            vmaddr: U64::new(endian, segment.vmaddr),
+            vmsize: U64::new(endian, segment.vmsize),
+            fileoff: U64::new(endian, segment.fileoff),
+            filesize: U64::new(endian, segment.filesize),
+            maxprot: U32::new(endian, segment.maxprot),
+            initprot: U32::new(endian, segment.initprot),
+            nsects: U32::new(endian, segment.nsects),
+            flags: U32::new(endian, segment.flags),
+        };
+        buffer.write(&segment);
+    }
+
+    fn write_section(&self, buffer: &mut dyn WritableBuffer, section: SectionHeader) {
+        let endian = self.endian;
+        let section = macho::Section64 {
+            sectname: section.sectname,
+            segname: section.segname,
+            addr: U64::new(endian, section.addr),
+            size: U64::new(endian, section.size),
+            offset: U32::new(endian, section.offset),
+            align: U32::new(endian, section.align),
+            reloff: U32::new(endian, section.reloff),
+            nreloc: U32::new(endian, section.nreloc),
+            flags: U32::new(endian, section.flags),
+            reserved1: U32::default(),
+            reserved2: U32::default(),
+            reserved3: U32::default(),
+        };
+        buffer.write(&section);
+    }
+
+    fn write_nlist(&self, buffer: &mut dyn WritableBuffer, nlist: Nlist) {
+        let endian = self.endian;
+        let nlist = macho::Nlist64 {
+            n_strx: U32::new(endian, nlist.n_strx),
+            n_type: nlist.n_type,
+            n_sect: nlist.n_sect,
+            n_desc: U16::new(endian, nlist.n_desc),
+            n_value: U64Bytes::new(endian, nlist.n_value),
+        };
+        buffer.write(&nlist);
+    }
+}
diff --git a/vendor/object/src/write/mod.rs b/vendor/object/src/write/mod.rs
new file mode 100644
index 0000000..cea4d2e
--- /dev/null
+++ b/vendor/object/src/write/mod.rs
@@ -0,0 +1,961 @@
+//! Interface for writing object files.
+
+use alloc::borrow::Cow;
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::{fmt, result, str};
+#[cfg(not(feature = "std"))]
+use hashbrown::HashMap;
+#[cfg(feature = "std")]
+use std::{boxed::Box, collections::HashMap, error, io};
+
+use crate::endian::{Endianness, U32, U64};
+use crate::{
+    Architecture, BinaryFormat, ComdatKind, FileFlags, RelocationEncoding, RelocationKind,
+    SectionFlags, SectionKind, SubArchitecture, SymbolFlags, SymbolKind, SymbolScope,
+};
+
+#[cfg(feature = "coff")]
+pub mod coff;
+#[cfg(feature = "coff")]
+pub use coff::CoffExportStyle;
+
+#[cfg(feature = "elf")]
+pub mod elf;
+
+#[cfg(feature = "macho")]
+mod macho;
+#[cfg(feature = "macho")]
+pub use macho::MachOBuildVersion;
+
+#[cfg(feature = "pe")]
+pub mod pe;
+
+#[cfg(feature = "xcoff")]
+mod xcoff;
+
+mod string;
+pub use string::StringId;
+
+mod util;
+pub use util::*;
+
+/// The error type used within the write module.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Error(String);
+
+impl fmt::Display for Error {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.0)
+    }
+}
+
+#[cfg(feature = "std")]
+impl error::Error for Error {}
+
+/// The result type used within the write module.
+pub type Result<T> = result::Result<T, Error>;
+
+/// A writable relocatable object file.
+#[derive(Debug)]
+pub struct Object<'a> {
+    format: BinaryFormat,
+    architecture: Architecture,
+    sub_architecture: Option<SubArchitecture>,
+    endian: Endianness,
+    sections: Vec<Section<'a>>,
+    standard_sections: HashMap<StandardSection, SectionId>,
+    symbols: Vec<Symbol>,
+    symbol_map: HashMap<Vec<u8>, SymbolId>,
+    stub_symbols: HashMap<SymbolId, SymbolId>,
+    comdats: Vec<Comdat>,
+    /// File flags that are specific to each file format.
+    pub flags: FileFlags,
+    /// The symbol name mangling scheme.
+    pub mangling: Mangling,
+    /// Mach-O "_tlv_bootstrap" symbol.
+    tlv_bootstrap: Option<SymbolId>,
+    /// Mach-O CPU subtype.
+    #[cfg(feature = "macho")]
+    macho_cpu_subtype: Option<u32>,
+    #[cfg(feature = "macho")]
+    macho_build_version: Option<MachOBuildVersion>,
+}
+
+impl<'a> Object<'a> {
+    /// Create an empty object file.
+    pub fn new(format: BinaryFormat, architecture: Architecture, endian: Endianness) -> Object<'a> {
+        Object {
+            format,
+            architecture,
+            sub_architecture: None,
+            endian,
+            sections: Vec::new(),
+            standard_sections: HashMap::new(),
+            symbols: Vec::new(),
+            symbol_map: HashMap::new(),
+            stub_symbols: HashMap::new(),
+            comdats: Vec::new(),
+            flags: FileFlags::None,
+            mangling: Mangling::default(format, architecture),
+            tlv_bootstrap: None,
+            #[cfg(feature = "macho")]
+            macho_cpu_subtype: None,
+            #[cfg(feature = "macho")]
+            macho_build_version: None,
+        }
+    }
+
+    /// Return the file format.
+    #[inline]
+    pub fn format(&self) -> BinaryFormat {
+        self.format
+    }
+
+    /// Return the architecture.
+    #[inline]
+    pub fn architecture(&self) -> Architecture {
+        self.architecture
+    }
+
+    /// Return the sub-architecture.
+    #[inline]
+    pub fn sub_architecture(&self) -> Option<SubArchitecture> {
+        self.sub_architecture
+    }
+
+    /// Specify the sub-architecture.
+    pub fn set_sub_architecture(&mut self, sub_architecture: Option<SubArchitecture>) {
+        self.sub_architecture = sub_architecture;
+    }
+
+    /// Return the current mangling setting.
+    #[inline]
+    pub fn mangling(&self) -> Mangling {
+        self.mangling
+    }
+
+    /// Specify the mangling setting.
+    #[inline]
+    pub fn set_mangling(&mut self, mangling: Mangling) {
+        self.mangling = mangling;
+    }
+
+    /// Return the name for a standard segment.
+    ///
+    /// This will vary based on the file format.
+    #[allow(unused_variables)]
+    pub fn segment_name(&self, segment: StandardSegment) -> &'static [u8] {
+        match self.format {
+            #[cfg(feature = "coff")]
+            BinaryFormat::Coff => &[],
+            #[cfg(feature = "elf")]
+            BinaryFormat::Elf => &[],
+            #[cfg(feature = "macho")]
+            BinaryFormat::MachO => self.macho_segment_name(segment),
+            _ => unimplemented!(),
+        }
+    }
+
+    /// Get the section with the given `SectionId`.
+    #[inline]
+    pub fn section(&self, section: SectionId) -> &Section<'a> {
+        &self.sections[section.0]
+    }
+
+    /// Mutably get the section with the given `SectionId`.
+    #[inline]
+    pub fn section_mut(&mut self, section: SectionId) -> &mut Section<'a> {
+        &mut self.sections[section.0]
+    }
+
+    /// Set the data for an existing section.
+    ///
+    /// Must not be called for sections that already have data, or that contain uninitialized data.
+    pub fn set_section_data<T>(&mut self, section: SectionId, data: T, align: u64)
+    where
+        T: Into<Cow<'a, [u8]>>,
+    {
+        self.sections[section.0].set_data(data, align)
+    }
+
+    /// Append data to an existing section. Returns the section offset of the data.
+    pub fn append_section_data(&mut self, section: SectionId, data: &[u8], align: u64) -> u64 {
+        self.sections[section.0].append_data(data, align)
+    }
+
+    /// Append zero-initialized data to an existing section. Returns the section offset of the data.
+    pub fn append_section_bss(&mut self, section: SectionId, size: u64, align: u64) -> u64 {
+        self.sections[section.0].append_bss(size, align)
+    }
+
+    /// Return the `SectionId` of a standard section.
+    ///
+    /// If the section doesn't already exist then it is created.
+    pub fn section_id(&mut self, section: StandardSection) -> SectionId {
+        self.standard_sections
+            .get(&section)
+            .cloned()
+            .unwrap_or_else(|| {
+                let (segment, name, kind, flags) = self.section_info(section);
+                let id = self.add_section(segment.to_vec(), name.to_vec(), kind);
+                self.section_mut(id).flags = flags;
+                id
+            })
+    }
+
+    /// Add a new section and return its `SectionId`.
+    ///
+    /// This also creates a section symbol.
+    pub fn add_section(&mut self, segment: Vec<u8>, name: Vec<u8>, kind: SectionKind) -> SectionId {
+        let id = SectionId(self.sections.len());
+        self.sections.push(Section {
+            segment,
+            name,
+            kind,
+            size: 0,
+            align: 1,
+            data: Cow::Borrowed(&[]),
+            relocations: Vec::new(),
+            symbol: None,
+            flags: SectionFlags::None,
+        });
+
+        // Add to self.standard_sections if required. This may match multiple standard sections.
+        let section = &self.sections[id.0];
+        for standard_section in StandardSection::all() {
+            if !self.standard_sections.contains_key(standard_section) {
+                let (segment, name, kind, _flags) = self.section_info(*standard_section);
+                if segment == &*section.segment && name == &*section.name && kind == section.kind {
+                    self.standard_sections.insert(*standard_section, id);
+                }
+            }
+        }
+
+        id
+    }
+
+    fn section_info(
+        &self,
+        section: StandardSection,
+    ) -> (&'static [u8], &'static [u8], SectionKind, SectionFlags) {
+        match self.format {
+            #[cfg(feature = "coff")]
+            BinaryFormat::Coff => self.coff_section_info(section),
+            #[cfg(feature = "elf")]
+            BinaryFormat::Elf => self.elf_section_info(section),
+            #[cfg(feature = "macho")]
+            BinaryFormat::MachO => self.macho_section_info(section),
+            #[cfg(feature = "xcoff")]
+            BinaryFormat::Xcoff => self.xcoff_section_info(section),
+            _ => unimplemented!(),
+        }
+    }
+
+    /// Add a subsection. Returns the `SectionId` and section offset of the data.
+    pub fn add_subsection(
+        &mut self,
+        section: StandardSection,
+        name: &[u8],
+        data: &[u8],
+        align: u64,
+    ) -> (SectionId, u64) {
+        let section_id = if self.has_subsections_via_symbols() {
+            self.set_subsections_via_symbols();
+            self.section_id(section)
+        } else {
+            let (segment, name, kind, flags) = self.subsection_info(section, name);
+            let id = self.add_section(segment.to_vec(), name, kind);
+            self.section_mut(id).flags = flags;
+            id
+        };
+        let offset = self.append_section_data(section_id, data, align);
+        (section_id, offset)
+    }
+
+    fn has_subsections_via_symbols(&self) -> bool {
+        match self.format {
+            BinaryFormat::Coff | BinaryFormat::Elf | BinaryFormat::Xcoff => false,
+            BinaryFormat::MachO => true,
+            _ => unimplemented!(),
+        }
+    }
+
+    fn set_subsections_via_symbols(&mut self) {
+        match self.format {
+            #[cfg(feature = "macho")]
+            BinaryFormat::MachO => self.macho_set_subsections_via_symbols(),
+            _ => unimplemented!(),
+        }
+    }
+
+    fn subsection_info(
+        &self,
+        section: StandardSection,
+        value: &[u8],
+    ) -> (&'static [u8], Vec<u8>, SectionKind, SectionFlags) {
+        let (segment, section, kind, flags) = self.section_info(section);
+        let name = self.subsection_name(section, value);
+        (segment, name, kind, flags)
+    }
+
+    #[allow(unused_variables)]
+    fn subsection_name(&self, section: &[u8], value: &[u8]) -> Vec<u8> {
+        debug_assert!(!self.has_subsections_via_symbols());
+        match self.format {
+            #[cfg(feature = "coff")]
+            BinaryFormat::Coff => self.coff_subsection_name(section, value),
+            #[cfg(feature = "elf")]
+            BinaryFormat::Elf => self.elf_subsection_name(section, value),
+            _ => unimplemented!(),
+        }
+    }
+
+    /// Get the COMDAT section group with the given `ComdatId`.
+    #[inline]
+    pub fn comdat(&self, comdat: ComdatId) -> &Comdat {
+        &self.comdats[comdat.0]
+    }
+
+    /// Mutably get the COMDAT section group with the given `ComdatId`.
+    #[inline]
+    pub fn comdat_mut(&mut self, comdat: ComdatId) -> &mut Comdat {
+        &mut self.comdats[comdat.0]
+    }
+
+    /// Add a new COMDAT section group and return its `ComdatId`.
+    pub fn add_comdat(&mut self, comdat: Comdat) -> ComdatId {
+        let comdat_id = ComdatId(self.comdats.len());
+        self.comdats.push(comdat);
+        comdat_id
+    }
+
+    /// Get the `SymbolId` of the symbol with the given name.
+    pub fn symbol_id(&self, name: &[u8]) -> Option<SymbolId> {
+        self.symbol_map.get(name).cloned()
+    }
+
+    /// Get the symbol with the given `SymbolId`.
+    #[inline]
+    pub fn symbol(&self, symbol: SymbolId) -> &Symbol {
+        &self.symbols[symbol.0]
+    }
+
+    /// Mutably get the symbol with the given `SymbolId`.
+    #[inline]
+    pub fn symbol_mut(&mut self, symbol: SymbolId) -> &mut Symbol {
+        &mut self.symbols[symbol.0]
+    }
+
+    /// Add a new symbol and return its `SymbolId`.
+    pub fn add_symbol(&mut self, mut symbol: Symbol) -> SymbolId {
+        // Defined symbols must have a scope.
+        debug_assert!(symbol.is_undefined() || symbol.scope != SymbolScope::Unknown);
+        if symbol.kind == SymbolKind::Section {
+            // There can only be one section symbol, but update its flags, since
+            // the automatically generated section symbol will have none.
+            let symbol_id = self.section_symbol(symbol.section.id().unwrap());
+            if symbol.flags != SymbolFlags::None {
+                self.symbol_mut(symbol_id).flags = symbol.flags;
+            }
+            return symbol_id;
+        }
+        if !symbol.name.is_empty()
+            && (symbol.kind == SymbolKind::Text
+                || symbol.kind == SymbolKind::Data
+                || symbol.kind == SymbolKind::Tls)
+        {
+            let unmangled_name = symbol.name.clone();
+            if let Some(prefix) = self.mangling.global_prefix() {
+                symbol.name.insert(0, prefix);
+            }
+            let symbol_id = self.add_raw_symbol(symbol);
+            self.symbol_map.insert(unmangled_name, symbol_id);
+            symbol_id
+        } else {
+            self.add_raw_symbol(symbol)
+        }
+    }
+
+    fn add_raw_symbol(&mut self, symbol: Symbol) -> SymbolId {
+        let symbol_id = SymbolId(self.symbols.len());
+        self.symbols.push(symbol);
+        symbol_id
+    }
+
+    /// Return true if the file format supports `StandardSection::UninitializedTls`.
+    #[inline]
+    pub fn has_uninitialized_tls(&self) -> bool {
+        self.format != BinaryFormat::Coff
+    }
+
+    /// Return true if the file format supports `StandardSection::Common`.
+    #[inline]
+    pub fn has_common(&self) -> bool {
+        self.format == BinaryFormat::MachO
+    }
+
+    /// Add a new common symbol and return its `SymbolId`.
+    ///
+    /// For Mach-O, this appends the symbol to the `__common` section.
+    pub fn add_common_symbol(&mut self, mut symbol: Symbol, size: u64, align: u64) -> SymbolId {
+        if self.has_common() {
+            let symbol_id = self.add_symbol(symbol);
+            let section = self.section_id(StandardSection::Common);
+            self.add_symbol_bss(symbol_id, section, size, align);
+            symbol_id
+        } else {
+            symbol.section = SymbolSection::Common;
+            symbol.size = size;
+            self.add_symbol(symbol)
+        }
+    }
+
+    /// Add a new file symbol and return its `SymbolId`.
+    pub fn add_file_symbol(&mut self, name: Vec<u8>) -> SymbolId {
+        self.add_raw_symbol(Symbol {
+            name,
+            value: 0,
+            size: 0,
+            kind: SymbolKind::File,
+            scope: SymbolScope::Compilation,
+            weak: false,
+            section: SymbolSection::None,
+            flags: SymbolFlags::None,
+        })
+    }
+
+    /// Get the symbol for a section.
+    pub fn section_symbol(&mut self, section_id: SectionId) -> SymbolId {
+        let section = &mut self.sections[section_id.0];
+        if let Some(symbol) = section.symbol {
+            return symbol;
+        }
+        let name = if self.format == BinaryFormat::Coff {
+            section.name.clone()
+        } else {
+            Vec::new()
+        };
+        let symbol_id = SymbolId(self.symbols.len());
+        self.symbols.push(Symbol {
+            name,
+            value: 0,
+            size: 0,
+            kind: SymbolKind::Section,
+            scope: SymbolScope::Compilation,
+            weak: false,
+            section: SymbolSection::Section(section_id),
+            flags: SymbolFlags::None,
+        });
+        section.symbol = Some(symbol_id);
+        symbol_id
+    }
+
+    /// Append data to an existing section, and update a symbol to refer to it.
+    ///
+    /// For Mach-O, this also creates a `__thread_vars` entry for TLS symbols, and the
+    /// symbol will indirectly point to the added data via the `__thread_vars` entry.
+    ///
+    /// Returns the section offset of the data.
+    pub fn add_symbol_data(
+        &mut self,
+        symbol_id: SymbolId,
+        section: SectionId,
+        data: &[u8],
+        align: u64,
+    ) -> u64 {
+        let offset = self.append_section_data(section, data, align);
+        self.set_symbol_data(symbol_id, section, offset, data.len() as u64);
+        offset
+    }
+
+    /// Append zero-initialized data to an existing section, and update a symbol to refer to it.
+    ///
+    /// For Mach-O, this also creates a `__thread_vars` entry for TLS symbols, and the
+    /// symbol will indirectly point to the added data via the `__thread_vars` entry.
+    ///
+    /// Returns the section offset of the data.
+    pub fn add_symbol_bss(
+        &mut self,
+        symbol_id: SymbolId,
+        section: SectionId,
+        size: u64,
+        align: u64,
+    ) -> u64 {
+        let offset = self.append_section_bss(section, size, align);
+        self.set_symbol_data(symbol_id, section, offset, size);
+        offset
+    }
+
+    /// Update a symbol to refer to the given data within a section.
+    ///
+    /// For Mach-O, this also creates a `__thread_vars` entry for TLS symbols, and the
+    /// symbol will indirectly point to the data via the `__thread_vars` entry.
+    #[allow(unused_mut)]
+    pub fn set_symbol_data(
+        &mut self,
+        mut symbol_id: SymbolId,
+        section: SectionId,
+        offset: u64,
+        size: u64,
+    ) {
+        // Defined symbols must have a scope.
+        debug_assert!(self.symbol(symbol_id).scope != SymbolScope::Unknown);
+        match self.format {
+            #[cfg(feature = "macho")]
+            BinaryFormat::MachO => symbol_id = self.macho_add_thread_var(symbol_id),
+            _ => {}
+        }
+        let symbol = self.symbol_mut(symbol_id);
+        symbol.value = offset;
+        symbol.size = size;
+        symbol.section = SymbolSection::Section(section);
+    }
+
+    /// Convert a symbol to a section symbol and offset.
+    ///
+    /// Returns `None` if the symbol does not have a section.
+    pub fn symbol_section_and_offset(&mut self, symbol_id: SymbolId) -> Option<(SymbolId, u64)> {
+        let symbol = self.symbol(symbol_id);
+        if symbol.kind == SymbolKind::Section {
+            return Some((symbol_id, 0));
+        }
+        let symbol_offset = symbol.value;
+        let section = symbol.section.id()?;
+        let section_symbol = self.section_symbol(section);
+        Some((section_symbol, symbol_offset))
+    }
+
+    /// Add a relocation to a section.
+    ///
+    /// Relocations must only be added after the referenced symbols have been added
+    /// and defined (if applicable).
+    pub fn add_relocation(&mut self, section: SectionId, mut relocation: Relocation) -> Result<()> {
+        let addend = match self.format {
+            #[cfg(feature = "coff")]
+            BinaryFormat::Coff => self.coff_fixup_relocation(&mut relocation),
+            #[cfg(feature = "elf")]
+            BinaryFormat::Elf => self.elf_fixup_relocation(&mut relocation)?,
+            #[cfg(feature = "macho")]
+            BinaryFormat::MachO => self.macho_fixup_relocation(&mut relocation),
+            #[cfg(feature = "xcoff")]
+            BinaryFormat::Xcoff => self.xcoff_fixup_relocation(&mut relocation),
+            _ => unimplemented!(),
+        };
+        if addend != 0 {
+            self.write_relocation_addend(section, &relocation, addend)?;
+        }
+        self.sections[section.0].relocations.push(relocation);
+        Ok(())
+    }
+
+    fn write_relocation_addend(
+        &mut self,
+        section: SectionId,
+        relocation: &Relocation,
+        addend: i64,
+    ) -> Result<()> {
+        let data = self.sections[section.0].data_mut();
+        let offset = relocation.offset as usize;
+        match relocation.size {
+            32 => data.write_at(offset, &U32::new(self.endian, addend as u32)),
+            64 => data.write_at(offset, &U64::new(self.endian, addend as u64)),
+            _ => {
+                return Err(Error(format!(
+                    "unimplemented relocation addend {:?}",
+                    relocation
+                )));
+            }
+        }
+        .map_err(|_| {
+            Error(format!(
+                "invalid relocation offset {}+{} (max {})",
+                relocation.offset,
+                relocation.size,
+                data.len()
+            ))
+        })
+    }
+
+    /// Write the object to a `Vec`.
+    pub fn write(&self) -> Result<Vec<u8>> {
+        let mut buffer = Vec::new();
+        self.emit(&mut buffer)?;
+        Ok(buffer)
+    }
+
+    /// Write the object to a `Write` implementation.
+    ///
+    /// Also flushes the writer.
+    ///
+    /// It is advisable to use a buffered writer like [`BufWriter`](std::io::BufWriter)
+    /// instead of an unbuffered writer like [`File`](std::fs::File).
+    #[cfg(feature = "std")]
+    pub fn write_stream<W: io::Write>(&self, w: W) -> result::Result<(), Box<dyn error::Error>> {
+        let mut stream = StreamingBuffer::new(w);
+        self.emit(&mut stream)?;
+        stream.result()?;
+        stream.into_inner().flush()?;
+        Ok(())
+    }
+
+    /// Write the object to a `WritableBuffer`.
+    pub fn emit(&self, buffer: &mut dyn WritableBuffer) -> Result<()> {
+        match self.format {
+            #[cfg(feature = "coff")]
+            BinaryFormat::Coff => self.coff_write(buffer),
+            #[cfg(feature = "elf")]
+            BinaryFormat::Elf => self.elf_write(buffer),
+            #[cfg(feature = "macho")]
+            BinaryFormat::MachO => self.macho_write(buffer),
+            #[cfg(feature = "xcoff")]
+            BinaryFormat::Xcoff => self.xcoff_write(buffer),
+            _ => unimplemented!(),
+        }
+    }
+}
+
+/// A standard segment kind.
+#[allow(missing_docs)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[non_exhaustive]
+pub enum StandardSegment {
+    Text,
+    Data,
+    Debug,
+}
+
+/// A standard section kind.
+#[allow(missing_docs)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[non_exhaustive]
+pub enum StandardSection {
+    Text,
+    Data,
+    ReadOnlyData,
+    ReadOnlyDataWithRel,
+    ReadOnlyString,
+    UninitializedData,
+    Tls,
+    /// Zero-fill TLS initializers. Unsupported for COFF.
+    UninitializedTls,
+    /// TLS variable structures. Only supported for Mach-O.
+    TlsVariables,
+    /// Common data. Only supported for Mach-O.
+    Common,
+    /// Notes for GNU properties. Only supported for ELF.
+    GnuProperty,
+}
+
+impl StandardSection {
+    /// Return the section kind of a standard section.
+    pub fn kind(self) -> SectionKind {
+        match self {
+            StandardSection::Text => SectionKind::Text,
+            StandardSection::Data => SectionKind::Data,
+            StandardSection::ReadOnlyData => SectionKind::ReadOnlyData,
+            StandardSection::ReadOnlyDataWithRel => SectionKind::ReadOnlyDataWithRel,
+            StandardSection::ReadOnlyString => SectionKind::ReadOnlyString,
+            StandardSection::UninitializedData => SectionKind::UninitializedData,
+            StandardSection::Tls => SectionKind::Tls,
+            StandardSection::UninitializedTls => SectionKind::UninitializedTls,
+            StandardSection::TlsVariables => SectionKind::TlsVariables,
+            StandardSection::Common => SectionKind::Common,
+            StandardSection::GnuProperty => SectionKind::Note,
+        }
+    }
+
+    // TODO: remembering to update this is error-prone, can we do better?
+    fn all() -> &'static [StandardSection] {
+        &[
+            StandardSection::Text,
+            StandardSection::Data,
+            StandardSection::ReadOnlyData,
+            StandardSection::ReadOnlyDataWithRel,
+            StandardSection::ReadOnlyString,
+            StandardSection::UninitializedData,
+            StandardSection::Tls,
+            StandardSection::UninitializedTls,
+            StandardSection::TlsVariables,
+            StandardSection::Common,
+            StandardSection::GnuProperty,
+        ]
+    }
+}
+
+/// An identifier used to reference a section.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SectionId(usize);
+
+/// A section in an object file.
+#[derive(Debug)]
+pub struct Section<'a> {
+    segment: Vec<u8>,
+    name: Vec<u8>,
+    kind: SectionKind,
+    size: u64,
+    align: u64,
+    data: Cow<'a, [u8]>,
+    relocations: Vec<Relocation>,
+    symbol: Option<SymbolId>,
+    /// Section flags that are specific to each file format.
+    pub flags: SectionFlags,
+}
+
+impl<'a> Section<'a> {
+    /// Try to convert the name to a utf8 string.
+    #[inline]
+    pub fn name(&self) -> Option<&str> {
+        str::from_utf8(&self.name).ok()
+    }
+
+    /// Try to convert the segment to a utf8 string.
+    #[inline]
+    pub fn segment(&self) -> Option<&str> {
+        str::from_utf8(&self.segment).ok()
+    }
+
+    /// Return true if this section contains zerofill data.
+    #[inline]
+    pub fn is_bss(&self) -> bool {
+        self.kind.is_bss()
+    }
+
+    /// Set the data for a section.
+    ///
+    /// Must not be called for sections that already have data, or that contain uninitialized data.
+    pub fn set_data<T>(&mut self, data: T, align: u64)
+    where
+        T: Into<Cow<'a, [u8]>>,
+    {
+        debug_assert!(!self.is_bss());
+        debug_assert_eq!(align & (align - 1), 0);
+        debug_assert!(self.data.is_empty());
+        self.data = data.into();
+        self.size = self.data.len() as u64;
+        self.align = align;
+    }
+
+    /// Append data to a section.
+    ///
+    /// Must not be called for sections that contain uninitialized data.
+    pub fn append_data(&mut self, append_data: &[u8], align: u64) -> u64 {
+        debug_assert!(!self.is_bss());
+        debug_assert_eq!(align & (align - 1), 0);
+        if self.align < align {
+            self.align = align;
+        }
+        let align = align as usize;
+        let data = self.data.to_mut();
+        let mut offset = data.len();
+        if offset & (align - 1) != 0 {
+            offset += align - (offset & (align - 1));
+            data.resize(offset, 0);
+        }
+        data.extend_from_slice(append_data);
+        self.size = data.len() as u64;
+        offset as u64
+    }
+
+    /// Append uninitialized data to a section.
+    ///
+    /// Must not be called for sections that contain initialized data.
+    pub fn append_bss(&mut self, size: u64, align: u64) -> u64 {
+        debug_assert!(self.is_bss());
+        debug_assert_eq!(align & (align - 1), 0);
+        if self.align < align {
+            self.align = align;
+        }
+        let mut offset = self.size;
+        if offset & (align - 1) != 0 {
+            offset += align - (offset & (align - 1));
+            self.size = offset;
+        }
+        self.size += size;
+        offset
+    }
+
+    /// Returns the section as-built so far.
+    ///
+    /// This requires that the section is not a bss section.
+    pub fn data(&self) -> &[u8] {
+        debug_assert!(!self.is_bss());
+        &self.data
+    }
+
+    /// Returns the section as-built so far.
+    ///
+    /// This requires that the section is not a bss section.
+    pub fn data_mut(&mut self) -> &mut [u8] {
+        debug_assert!(!self.is_bss());
+        self.data.to_mut()
+    }
+}
+
+/// The section where a symbol is defined.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[non_exhaustive]
+pub enum SymbolSection {
+    /// The section is not applicable for this symbol (such as file symbols).
+    None,
+    /// The symbol is undefined.
+    Undefined,
+    /// The symbol has an absolute value.
+    Absolute,
+    /// The symbol is a zero-initialized symbol that will be combined with duplicate definitions.
+    Common,
+    /// The symbol is defined in the given section.
+    Section(SectionId),
+}
+
+impl SymbolSection {
+    /// Returns the section id for the section where the symbol is defined.
+    ///
+    /// May return `None` if the symbol is not defined in a section.
+    #[inline]
+    pub fn id(self) -> Option<SectionId> {
+        if let SymbolSection::Section(id) = self {
+            Some(id)
+        } else {
+            None
+        }
+    }
+}
+
+/// An identifier used to reference a symbol.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SymbolId(usize);
+
+/// A symbol in an object file.
+#[derive(Debug)]
+pub struct Symbol {
+    /// The name of the symbol.
+    pub name: Vec<u8>,
+    /// The value of the symbol.
+    ///
+    /// If the symbol defined in a section, then this is the section offset of the symbol.
+    pub value: u64,
+    /// The size of the symbol.
+    pub size: u64,
+    /// The kind of the symbol.
+    pub kind: SymbolKind,
+    /// The scope of the symbol.
+    pub scope: SymbolScope,
+    /// Whether the symbol has weak binding.
+    pub weak: bool,
+    /// The section containing the symbol.
+    pub section: SymbolSection,
+    /// Symbol flags that are specific to each file format.
+    pub flags: SymbolFlags<SectionId, SymbolId>,
+}
+
+impl Symbol {
+    /// Try to convert the name to a utf8 string.
+    #[inline]
+    pub fn name(&self) -> Option<&str> {
+        str::from_utf8(&self.name).ok()
+    }
+
+    /// Return true if the symbol is undefined.
+    #[inline]
+    pub fn is_undefined(&self) -> bool {
+        self.section == SymbolSection::Undefined
+    }
+
+    /// Return true if the symbol is common data.
+    ///
+    /// Note: does not check for `SymbolSection::Section` with `SectionKind::Common`.
+    #[inline]
+    pub fn is_common(&self) -> bool {
+        self.section == SymbolSection::Common
+    }
+
+    /// Return true if the symbol scope is local.
+    #[inline]
+    pub fn is_local(&self) -> bool {
+        self.scope == SymbolScope::Compilation
+    }
+}
+
+/// A relocation in an object file.
+#[derive(Debug)]
+pub struct Relocation {
+    /// The section offset of the place of the relocation.
+    pub offset: u64,
+    /// The size in bits of the place of relocation.
+    pub size: u8,
+    /// The operation used to calculate the result of the relocation.
+    pub kind: RelocationKind,
+    /// Information about how the result of the relocation operation is encoded in the place.
+    pub encoding: RelocationEncoding,
+    /// The symbol referred to by the relocation.
+    ///
+    /// This may be a section symbol.
+    pub symbol: SymbolId,
+    /// The addend to use in the relocation calculation.
+    ///
+    /// This may be in addition to an implicit addend stored at the place of the relocation.
+    pub addend: i64,
+}
+
+/// An identifier used to reference a COMDAT section group.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ComdatId(usize);
+
+/// A COMDAT section group.
+#[derive(Debug)]
+pub struct Comdat {
+    /// The COMDAT selection kind.
+    ///
+    /// This determines the way in which the linker resolves multiple definitions of the COMDAT
+    /// sections.
+    pub kind: ComdatKind,
+    /// The COMDAT symbol.
+    ///
+    /// If this symbol is referenced, then all sections in the group will be included by the
+    /// linker.
+    pub symbol: SymbolId,
+    /// The sections in the group.
+    pub sections: Vec<SectionId>,
+}
+
+/// The symbol name mangling scheme.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[non_exhaustive]
+pub enum Mangling {
+    /// No symbol mangling.
+    None,
+    /// Windows COFF symbol mangling.
+    Coff,
+    /// Windows COFF i386 symbol mangling.
+    CoffI386,
+    /// ELF symbol mangling.
+    Elf,
+    /// Mach-O symbol mangling.
+    MachO,
+    /// Xcoff symbol mangling.
+    Xcoff,
+}
+
+impl Mangling {
+    /// Return the default symboling mangling for the given format and architecture.
+    pub fn default(format: BinaryFormat, architecture: Architecture) -> Self {
+        match (format, architecture) {
+            (BinaryFormat::Coff, Architecture::I386) => Mangling::CoffI386,
+            (BinaryFormat::Coff, _) => Mangling::Coff,
+            (BinaryFormat::Elf, _) => Mangling::Elf,
+            (BinaryFormat::MachO, _) => Mangling::MachO,
+            (BinaryFormat::Xcoff, _) => Mangling::Xcoff,
+            _ => Mangling::None,
+        }
+    }
+
+    /// Return the prefix to use for global symbols.
+    pub fn global_prefix(self) -> Option<u8> {
+        match self {
+            Mangling::None | Mangling::Elf | Mangling::Coff | Mangling::Xcoff => None,
+            Mangling::CoffI386 | Mangling::MachO => Some(b'_'),
+        }
+    }
+}
diff --git a/vendor/object/src/write/pe.rs b/vendor/object/src/write/pe.rs
new file mode 100644
index 0000000..70da3a0
--- /dev/null
+++ b/vendor/object/src/write/pe.rs
@@ -0,0 +1,847 @@
+//! Helper for writing PE files.
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::mem;
+
+use crate::endian::{LittleEndian as LE, *};
+use crate::pe;
+use crate::write::util;
+use crate::write::{Error, Result, WritableBuffer};
+
+/// A helper for writing PE files.
+///
+/// Writing uses a two phase approach. The first phase reserves file ranges and virtual
+/// address ranges for everything in the order that they will be written.
+///
+/// The second phase writes everything out in order. Thus the caller must ensure writing
+/// is in the same order that file ranges were reserved.
+#[allow(missing_debug_implementations)]
+pub struct Writer<'a> {
+    is_64: bool,
+    section_alignment: u32,
+    file_alignment: u32,
+
+    buffer: &'a mut dyn WritableBuffer,
+    len: u32,
+    virtual_len: u32,
+    headers_len: u32,
+
+    code_address: u32,
+    data_address: u32,
+    code_len: u32,
+    data_len: u32,
+    bss_len: u32,
+
+    nt_headers_offset: u32,
+    data_directories: Vec<DataDirectory>,
+    section_header_num: u16,
+    sections: Vec<Section>,
+
+    symbol_offset: u32,
+    symbol_num: u32,
+
+    reloc_blocks: Vec<RelocBlock>,
+    relocs: Vec<U16<LE>>,
+    reloc_offset: u32,
+}
+
+impl<'a> Writer<'a> {
+    /// Create a new `Writer`.
+    pub fn new(
+        is_64: bool,
+        section_alignment: u32,
+        file_alignment: u32,
+        buffer: &'a mut dyn WritableBuffer,
+    ) -> Self {
+        Writer {
+            is_64,
+            section_alignment,
+            file_alignment,
+
+            buffer,
+            len: 0,
+            virtual_len: 0,
+            headers_len: 0,
+
+            code_address: 0,
+            data_address: 0,
+            code_len: 0,
+            data_len: 0,
+            bss_len: 0,
+
+            nt_headers_offset: 0,
+            data_directories: Vec::new(),
+            section_header_num: 0,
+            sections: Vec::new(),
+
+            symbol_offset: 0,
+            symbol_num: 0,
+
+            reloc_blocks: Vec::new(),
+            relocs: Vec::new(),
+            reloc_offset: 0,
+        }
+    }
+
+    /// Return the current virtual address size that has been reserved.
+    ///
+    /// This is only valid after section headers have been reserved.
+    pub fn virtual_len(&self) -> u32 {
+        self.virtual_len
+    }
+
+    /// Reserve a virtual address range with the given size.
+    ///
+    /// The reserved length will be increased to match the section alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve_virtual(&mut self, len: u32) -> u32 {
+        let offset = self.virtual_len;
+        self.virtual_len += len;
+        self.virtual_len = util::align_u32(self.virtual_len, self.section_alignment);
+        offset
+    }
+
+    /// Reserve up to the given virtual address.
+    ///
+    /// The reserved length will be increased to match the section alignment.
+    pub fn reserve_virtual_until(&mut self, address: u32) {
+        debug_assert!(self.virtual_len <= address);
+        self.virtual_len = util::align_u32(address, self.section_alignment);
+    }
+
+    /// Return the current file length that has been reserved.
+    pub fn reserved_len(&self) -> u32 {
+        self.len
+    }
+
+    /// Return the current file length that has been written.
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> usize {
+        self.buffer.len()
+    }
+
+    /// Reserve a file range with the given size and starting alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve(&mut self, len: u32, align_start: u32) -> u32 {
+        if len == 0 {
+            return self.len;
+        }
+        self.reserve_align(align_start);
+        let offset = self.len;
+        self.len += len;
+        offset
+    }
+
+    /// Reserve a file range with the given size and using the file alignment.
+    ///
+    /// Returns the aligned offset of the start of the range.
+    pub fn reserve_file(&mut self, len: u32) -> u32 {
+        self.reserve(len, self.file_alignment)
+    }
+
+    /// Write data.
+    pub fn write(&mut self, data: &[u8]) {
+        self.buffer.write_bytes(data);
+    }
+
+    /// Reserve alignment padding bytes.
+    pub fn reserve_align(&mut self, align_start: u32) {
+        self.len = util::align_u32(self.len, align_start);
+    }
+
+    /// Write alignment padding bytes.
+    pub fn write_align(&mut self, align_start: u32) {
+        util::write_align(self.buffer, align_start as usize);
+    }
+
+    /// Write padding up to the next multiple of file alignment.
+    pub fn write_file_align(&mut self) {
+        self.write_align(self.file_alignment);
+    }
+
+    /// Reserve the file range up to the given file offset.
+    pub fn reserve_until(&mut self, offset: u32) {
+        debug_assert!(self.len <= offset);
+        self.len = offset;
+    }
+
+    /// Write padding up to the given file offset.
+    pub fn pad_until(&mut self, offset: u32) {
+        debug_assert!(self.buffer.len() <= offset as usize);
+        self.buffer.resize(offset as usize);
+    }
+
+    /// Reserve the range for the DOS header.
+    ///
+    /// This must be at the start of the file.
+    ///
+    /// When writing, you may use `write_custom_dos_header` or `write_empty_dos_header`.
+    pub fn reserve_dos_header(&mut self) {
+        debug_assert_eq!(self.len, 0);
+        self.reserve(mem::size_of::<pe::ImageDosHeader>() as u32, 1);
+    }
+
+    /// Write a custom DOS header.
+    ///
+    /// This must be at the start of the file.
+    pub fn write_custom_dos_header(&mut self, dos_header: &pe::ImageDosHeader) -> Result<()> {
+        debug_assert_eq!(self.buffer.len(), 0);
+
+        // Start writing.
+        self.buffer
+            .reserve(self.len as usize)
+            .map_err(|_| Error(String::from("Cannot allocate buffer")))?;
+
+        self.buffer.write(dos_header);
+        Ok(())
+    }
+
+    /// Write the DOS header for a file without a stub.
+    ///
+    /// This must be at the start of the file.
+    ///
+    /// Uses default values for all fields.
+    pub fn write_empty_dos_header(&mut self) -> Result<()> {
+        self.write_custom_dos_header(&pe::ImageDosHeader {
+            e_magic: U16::new(LE, pe::IMAGE_DOS_SIGNATURE),
+            e_cblp: U16::new(LE, 0),
+            e_cp: U16::new(LE, 0),
+            e_crlc: U16::new(LE, 0),
+            e_cparhdr: U16::new(LE, 0),
+            e_minalloc: U16::new(LE, 0),
+            e_maxalloc: U16::new(LE, 0),
+            e_ss: U16::new(LE, 0),
+            e_sp: U16::new(LE, 0),
+            e_csum: U16::new(LE, 0),
+            e_ip: U16::new(LE, 0),
+            e_cs: U16::new(LE, 0),
+            e_lfarlc: U16::new(LE, 0),
+            e_ovno: U16::new(LE, 0),
+            e_res: [U16::new(LE, 0); 4],
+            e_oemid: U16::new(LE, 0),
+            e_oeminfo: U16::new(LE, 0),
+            e_res2: [U16::new(LE, 0); 10],
+            e_lfanew: U32::new(LE, self.nt_headers_offset),
+        })
+    }
+
+    /// Reserve a fixed DOS header and stub.
+    ///
+    /// Use `reserve_dos_header` and `reserve` if you need a custom stub.
+    pub fn reserve_dos_header_and_stub(&mut self) {
+        self.reserve_dos_header();
+        self.reserve(64, 1);
+    }
+
+    /// Write a fixed DOS header and stub.
+    ///
+    /// Use `write_custom_dos_header` and `write` if you need a custom stub.
+    pub fn write_dos_header_and_stub(&mut self) -> Result<()> {
+        self.write_custom_dos_header(&pe::ImageDosHeader {
+            e_magic: U16::new(LE, pe::IMAGE_DOS_SIGNATURE),
+            e_cblp: U16::new(LE, 0x90),
+            e_cp: U16::new(LE, 3),
+            e_crlc: U16::new(LE, 0),
+            e_cparhdr: U16::new(LE, 4),
+            e_minalloc: U16::new(LE, 0),
+            e_maxalloc: U16::new(LE, 0xffff),
+            e_ss: U16::new(LE, 0),
+            e_sp: U16::new(LE, 0xb8),
+            e_csum: U16::new(LE, 0),
+            e_ip: U16::new(LE, 0),
+            e_cs: U16::new(LE, 0),
+            e_lfarlc: U16::new(LE, 0x40),
+            e_ovno: U16::new(LE, 0),
+            e_res: [U16::new(LE, 0); 4],
+            e_oemid: U16::new(LE, 0),
+            e_oeminfo: U16::new(LE, 0),
+            e_res2: [U16::new(LE, 0); 10],
+            e_lfanew: U32::new(LE, self.nt_headers_offset),
+        })?;
+
+        #[rustfmt::skip]
+        self.buffer.write_bytes(&[
+            0x0e, 0x1f, 0xba, 0x0e, 0x00, 0xb4, 0x09, 0xcd,
+            0x21, 0xb8, 0x01, 0x4c, 0xcd, 0x21, 0x54, 0x68,
+            0x69, 0x73, 0x20, 0x70, 0x72, 0x6f, 0x67, 0x72,
+            0x61, 0x6d, 0x20, 0x63, 0x61, 0x6e, 0x6e, 0x6f,
+            0x74, 0x20, 0x62, 0x65, 0x20, 0x72, 0x75, 0x6e,
+            0x20, 0x69, 0x6e, 0x20, 0x44, 0x4f, 0x53, 0x20,
+            0x6d, 0x6f, 0x64, 0x65, 0x2e, 0x0d, 0x0d, 0x0a,
+            0x24, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        ]);
+
+        Ok(())
+    }
+
+    fn nt_headers_size(&self) -> u32 {
+        if self.is_64 {
+            mem::size_of::<pe::ImageNtHeaders64>() as u32
+        } else {
+            mem::size_of::<pe::ImageNtHeaders32>() as u32
+        }
+    }
+
+    fn optional_header_size(&self) -> u32 {
+        let size = if self.is_64 {
+            mem::size_of::<pe::ImageOptionalHeader64>() as u32
+        } else {
+            mem::size_of::<pe::ImageOptionalHeader32>() as u32
+        };
+        size + self.data_directories.len() as u32 * mem::size_of::<pe::ImageDataDirectory>() as u32
+    }
+
+    /// Return the offset of the NT headers, if reserved.
+    pub fn nt_headers_offset(&self) -> u32 {
+        self.nt_headers_offset
+    }
+
+    /// Reserve the range for the NT headers.
+    pub fn reserve_nt_headers(&mut self, data_directory_num: usize) {
+        debug_assert_eq!(self.nt_headers_offset, 0);
+        self.nt_headers_offset = self.reserve(self.nt_headers_size(), 8);
+        self.data_directories = vec![DataDirectory::default(); data_directory_num];
+        self.reserve(
+            data_directory_num as u32 * mem::size_of::<pe::ImageDataDirectory>() as u32,
+            1,
+        );
+    }
+
+    /// Set the virtual address and size of a data directory.
+    pub fn set_data_directory(&mut self, index: usize, virtual_address: u32, size: u32) {
+        self.data_directories[index] = DataDirectory {
+            virtual_address,
+            size,
+        }
+    }
+
+    /// Write the NT headers.
+    pub fn write_nt_headers(&mut self, nt_headers: NtHeaders) {
+        self.pad_until(self.nt_headers_offset);
+        self.buffer.write(&U32::new(LE, pe::IMAGE_NT_SIGNATURE));
+        let file_header = pe::ImageFileHeader {
+            machine: U16::new(LE, nt_headers.machine),
+            number_of_sections: U16::new(LE, self.section_header_num),
+            time_date_stamp: U32::new(LE, nt_headers.time_date_stamp),
+            pointer_to_symbol_table: U32::new(LE, self.symbol_offset),
+            number_of_symbols: U32::new(LE, self.symbol_num),
+            size_of_optional_header: U16::new(LE, self.optional_header_size() as u16),
+            characteristics: U16::new(LE, nt_headers.characteristics),
+        };
+        self.buffer.write(&file_header);
+        if self.is_64 {
+            let optional_header = pe::ImageOptionalHeader64 {
+                magic: U16::new(LE, pe::IMAGE_NT_OPTIONAL_HDR64_MAGIC),
+                major_linker_version: nt_headers.major_linker_version,
+                minor_linker_version: nt_headers.minor_linker_version,
+                size_of_code: U32::new(LE, self.code_len),
+                size_of_initialized_data: U32::new(LE, self.data_len),
+                size_of_uninitialized_data: U32::new(LE, self.bss_len),
+                address_of_entry_point: U32::new(LE, nt_headers.address_of_entry_point),
+                base_of_code: U32::new(LE, self.code_address),
+                image_base: U64::new(LE, nt_headers.image_base),
+                section_alignment: U32::new(LE, self.section_alignment),
+                file_alignment: U32::new(LE, self.file_alignment),
+                major_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.major_operating_system_version,
+                ),
+                minor_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.minor_operating_system_version,
+                ),
+                major_image_version: U16::new(LE, nt_headers.major_image_version),
+                minor_image_version: U16::new(LE, nt_headers.minor_image_version),
+                major_subsystem_version: U16::new(LE, nt_headers.major_subsystem_version),
+                minor_subsystem_version: U16::new(LE, nt_headers.minor_subsystem_version),
+                win32_version_value: U32::new(LE, 0),
+                size_of_image: U32::new(LE, self.virtual_len),
+                size_of_headers: U32::new(LE, self.headers_len),
+                check_sum: U32::new(LE, 0),
+                subsystem: U16::new(LE, nt_headers.subsystem),
+                dll_characteristics: U16::new(LE, nt_headers.dll_characteristics),
+                size_of_stack_reserve: U64::new(LE, nt_headers.size_of_stack_reserve),
+                size_of_stack_commit: U64::new(LE, nt_headers.size_of_stack_commit),
+                size_of_heap_reserve: U64::new(LE, nt_headers.size_of_heap_reserve),
+                size_of_heap_commit: U64::new(LE, nt_headers.size_of_heap_commit),
+                loader_flags: U32::new(LE, 0),
+                number_of_rva_and_sizes: U32::new(LE, self.data_directories.len() as u32),
+            };
+            self.buffer.write(&optional_header);
+        } else {
+            let optional_header = pe::ImageOptionalHeader32 {
+                magic: U16::new(LE, pe::IMAGE_NT_OPTIONAL_HDR32_MAGIC),
+                major_linker_version: nt_headers.major_linker_version,
+                minor_linker_version: nt_headers.minor_linker_version,
+                size_of_code: U32::new(LE, self.code_len),
+                size_of_initialized_data: U32::new(LE, self.data_len),
+                size_of_uninitialized_data: U32::new(LE, self.bss_len),
+                address_of_entry_point: U32::new(LE, nt_headers.address_of_entry_point),
+                base_of_code: U32::new(LE, self.code_address),
+                base_of_data: U32::new(LE, self.data_address),
+                image_base: U32::new(LE, nt_headers.image_base as u32),
+                section_alignment: U32::new(LE, self.section_alignment),
+                file_alignment: U32::new(LE, self.file_alignment),
+                major_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.major_operating_system_version,
+                ),
+                minor_operating_system_version: U16::new(
+                    LE,
+                    nt_headers.minor_operating_system_version,
+                ),
+                major_image_version: U16::new(LE, nt_headers.major_image_version),
+                minor_image_version: U16::new(LE, nt_headers.minor_image_version),
+                major_subsystem_version: U16::new(LE, nt_headers.major_subsystem_version),
+                minor_subsystem_version: U16::new(LE, nt_headers.minor_subsystem_version),
+                win32_version_value: U32::new(LE, 0),
+                size_of_image: U32::new(LE, self.virtual_len),
+                size_of_headers: U32::new(LE, self.headers_len),
+                check_sum: U32::new(LE, 0),
+                subsystem: U16::new(LE, nt_headers.subsystem),
+                dll_characteristics: U16::new(LE, nt_headers.dll_characteristics),
+                size_of_stack_reserve: U32::new(LE, nt_headers.size_of_stack_reserve as u32),
+                size_of_stack_commit: U32::new(LE, nt_headers.size_of_stack_commit as u32),
+                size_of_heap_reserve: U32::new(LE, nt_headers.size_of_heap_reserve as u32),
+                size_of_heap_commit: U32::new(LE, nt_headers.size_of_heap_commit as u32),
+                loader_flags: U32::new(LE, 0),
+                number_of_rva_and_sizes: U32::new(LE, self.data_directories.len() as u32),
+            };
+            self.buffer.write(&optional_header);
+        }
+
+        for dir in &self.data_directories {
+            self.buffer.write(&pe::ImageDataDirectory {
+                virtual_address: U32::new(LE, dir.virtual_address),
+                size: U32::new(LE, dir.size),
+            })
+        }
+    }
+
+    /// Reserve the section headers.
+    ///
+    /// The number of reserved section headers must be the same as the number of sections that
+    /// are later reserved.
+    // TODO: change this to a maximum number of sections?
+    pub fn reserve_section_headers(&mut self, section_header_num: u16) {
+        debug_assert_eq!(self.section_header_num, 0);
+        self.section_header_num = section_header_num;
+        self.reserve(
+            u32::from(section_header_num) * mem::size_of::<pe::ImageSectionHeader>() as u32,
+            1,
+        );
+        // Padding before sections must be included in headers_len.
+        self.reserve_align(self.file_alignment);
+        self.headers_len = self.len;
+        self.reserve_virtual(self.len);
+    }
+
+    /// Write the section headers.
+    ///
+    /// This uses information that was recorded when the sections were reserved.
+    pub fn write_section_headers(&mut self) {
+        debug_assert_eq!(self.section_header_num as usize, self.sections.len());
+        for section in &self.sections {
+            let section_header = pe::ImageSectionHeader {
+                name: section.name,
+                virtual_size: U32::new(LE, section.range.virtual_size),
+                virtual_address: U32::new(LE, section.range.virtual_address),
+                size_of_raw_data: U32::new(LE, section.range.file_size),
+                pointer_to_raw_data: U32::new(LE, section.range.file_offset),
+                pointer_to_relocations: U32::new(LE, 0),
+                pointer_to_linenumbers: U32::new(LE, 0),
+                number_of_relocations: U16::new(LE, 0),
+                number_of_linenumbers: U16::new(LE, 0),
+                characteristics: U32::new(LE, section.characteristics),
+            };
+            self.buffer.write(&section_header);
+        }
+    }
+
+    /// Reserve a section.
+    ///
+    /// Returns the file range and virtual address range that are reserved
+    /// for the section.
+    pub fn reserve_section(
+        &mut self,
+        name: [u8; 8],
+        characteristics: u32,
+        virtual_size: u32,
+        data_size: u32,
+    ) -> SectionRange {
+        let virtual_address = self.reserve_virtual(virtual_size);
+
+        // Padding after section must be included in section file size.
+        let file_size = util::align_u32(data_size, self.file_alignment);
+        let file_offset = if file_size != 0 {
+            self.reserve(file_size, self.file_alignment)
+        } else {
+            0
+        };
+
+        // Sizes in optional header use the virtual size with the file alignment.
+        let aligned_virtual_size = util::align_u32(virtual_size, self.file_alignment);
+        if characteristics & pe::IMAGE_SCN_CNT_CODE != 0 {
+            if self.code_address == 0 {
+                self.code_address = virtual_address;
+            }
+            self.code_len += aligned_virtual_size;
+        } else if characteristics & pe::IMAGE_SCN_CNT_INITIALIZED_DATA != 0 {
+            if self.data_address == 0 {
+                self.data_address = virtual_address;
+            }
+            self.data_len += aligned_virtual_size;
+        } else if characteristics & pe::IMAGE_SCN_CNT_UNINITIALIZED_DATA != 0 {
+            if self.data_address == 0 {
+                self.data_address = virtual_address;
+            }
+            self.bss_len += aligned_virtual_size;
+        }
+
+        let range = SectionRange {
+            virtual_address,
+            virtual_size,
+            file_offset,
+            file_size,
+        };
+        self.sections.push(Section {
+            name,
+            characteristics,
+            range,
+        });
+        range
+    }
+
+    /// Write the data for a section.
+    pub fn write_section(&mut self, offset: u32, data: &[u8]) {
+        if data.is_empty() {
+            return;
+        }
+        self.pad_until(offset);
+        self.write(data);
+        self.write_align(self.file_alignment);
+    }
+
+    /// Reserve a `.text` section.
+    ///
+    /// Contains executable code.
+    pub fn reserve_text_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".text\0\0\0",
+            pe::IMAGE_SCN_CNT_CODE | pe::IMAGE_SCN_MEM_EXECUTE | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        )
+    }
+
+    /// Reserve a `.data` section.
+    ///
+    /// Contains initialized data.
+    ///
+    /// May also contain uninitialized data if `virtual_size` is greater than `data_size`.
+    pub fn reserve_data_section(&mut self, virtual_size: u32, data_size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".data\0\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ | pe::IMAGE_SCN_MEM_WRITE,
+            virtual_size,
+            data_size,
+        )
+    }
+
+    /// Reserve a `.rdata` section.
+    ///
+    /// Contains read-only initialized data.
+    pub fn reserve_rdata_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".rdata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        )
+    }
+
+    /// Reserve a `.bss` section.
+    ///
+    /// Contains uninitialized data.
+    pub fn reserve_bss_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".bss\0\0\0\0",
+            pe::IMAGE_SCN_CNT_UNINITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ | pe::IMAGE_SCN_MEM_WRITE,
+            size,
+            0,
+        )
+    }
+
+    /// Reserve an `.idata` section.
+    ///
+    /// Contains import tables. Note that it is permissible to store import tables in a different
+    /// section.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_IMPORT` data directory.
+    pub fn reserve_idata_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".idata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ | pe::IMAGE_SCN_MEM_WRITE,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_IMPORT];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Reserve an `.edata` section.
+    ///
+    /// Contains export tables.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_EXPORT` data directory.
+    pub fn reserve_edata_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".edata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_EXPORT];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Reserve a `.pdata` section.
+    ///
+    /// Contains exception information.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_EXCEPTION` data directory.
+    pub fn reserve_pdata_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".pdata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_EXCEPTION];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Reserve a `.xdata` section.
+    ///
+    /// Contains exception information.
+    pub fn reserve_xdata_section(&mut self, size: u32) -> SectionRange {
+        self.reserve_section(
+            *b".xdata\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        )
+    }
+
+    /// Reserve a `.rsrc` section.
+    ///
+    /// Contains the resource directory.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_RESOURCE` data directory.
+    pub fn reserve_rsrc_section(&mut self, size: u32) -> SectionRange {
+        let range = self.reserve_section(
+            *b".rsrc\0\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA | pe::IMAGE_SCN_MEM_READ,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_RESOURCE];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        range
+    }
+
+    /// Add a base relocation.
+    ///
+    /// `typ` must be one of the `IMAGE_REL_BASED_*` constants.
+    pub fn add_reloc(&mut self, mut virtual_address: u32, typ: u16) {
+        let reloc = U16::new(LE, typ << 12 | (virtual_address & 0xfff) as u16);
+        virtual_address &= !0xfff;
+        if let Some(block) = self.reloc_blocks.last_mut() {
+            if block.virtual_address == virtual_address {
+                self.relocs.push(reloc);
+                block.count += 1;
+                return;
+            }
+            // Blocks must have an even number of relocations.
+            if block.count & 1 != 0 {
+                self.relocs.push(U16::new(LE, 0));
+                block.count += 1;
+            }
+            debug_assert!(block.virtual_address < virtual_address);
+        }
+        self.relocs.push(reloc);
+        self.reloc_blocks.push(RelocBlock {
+            virtual_address,
+            count: 1,
+        });
+    }
+
+    /// Return true if a base relocation has been added.
+    pub fn has_relocs(&mut self) -> bool {
+        !self.relocs.is_empty()
+    }
+
+    /// Reserve a `.reloc` section.
+    ///
+    /// This contains the base relocations that were added with `add_reloc`.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_BASERELOC` data directory.
+    pub fn reserve_reloc_section(&mut self) -> SectionRange {
+        if let Some(block) = self.reloc_blocks.last_mut() {
+            // Blocks must have an even number of relocations.
+            if block.count & 1 != 0 {
+                self.relocs.push(U16::new(LE, 0));
+                block.count += 1;
+            }
+        }
+        let size = self.reloc_blocks.iter().map(RelocBlock::size).sum();
+        let range = self.reserve_section(
+            *b".reloc\0\0",
+            pe::IMAGE_SCN_CNT_INITIALIZED_DATA
+                | pe::IMAGE_SCN_MEM_READ
+                | pe::IMAGE_SCN_MEM_DISCARDABLE,
+            size,
+            size,
+        );
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_BASERELOC];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: range.virtual_address,
+            size,
+        };
+        self.reloc_offset = range.file_offset;
+        range
+    }
+
+    /// Write a `.reloc` section.
+    ///
+    /// This contains the base relocations that were added with `add_reloc`.
+    pub fn write_reloc_section(&mut self) {
+        if self.reloc_offset == 0 {
+            return;
+        }
+        self.pad_until(self.reloc_offset);
+
+        let mut total = 0;
+        for block in &self.reloc_blocks {
+            self.buffer.write(&pe::ImageBaseRelocation {
+                virtual_address: U32::new(LE, block.virtual_address),
+                size_of_block: U32::new(LE, block.size()),
+            });
+            self.buffer
+                .write_slice(&self.relocs[total..][..block.count as usize]);
+            total += block.count as usize;
+        }
+        debug_assert_eq!(total, self.relocs.len());
+
+        self.write_align(self.file_alignment);
+    }
+
+    /// Reserve the certificate table.
+    ///
+    /// This also sets the `pe::IMAGE_DIRECTORY_ENTRY_SECURITY` data directory.
+    // TODO: reserve individual certificates
+    pub fn reserve_certificate_table(&mut self, size: u32) {
+        let size = util::align_u32(size, 8);
+        let offset = self.reserve(size, 8);
+        let dir = &mut self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_SECURITY];
+        debug_assert_eq!(dir.virtual_address, 0);
+        *dir = DataDirectory {
+            virtual_address: offset,
+            size,
+        };
+    }
+
+    /// Write the certificate table.
+    // TODO: write individual certificates
+    pub fn write_certificate_table(&mut self, data: &[u8]) {
+        let dir = self.data_directories[pe::IMAGE_DIRECTORY_ENTRY_SECURITY];
+        self.pad_until(dir.virtual_address);
+        self.write(data);
+        self.pad_until(dir.virtual_address + dir.size);
+    }
+}
+
+/// Information required for writing [`pe::ImageNtHeaders32`] or [`pe::ImageNtHeaders64`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct NtHeaders {
+    // ImageFileHeader
+    pub machine: u16,
+    pub time_date_stamp: u32,
+    pub characteristics: u16,
+    // ImageOptionalHeader
+    pub major_linker_version: u8,
+    pub minor_linker_version: u8,
+    pub address_of_entry_point: u32,
+    pub image_base: u64,
+    pub major_operating_system_version: u16,
+    pub minor_operating_system_version: u16,
+    pub major_image_version: u16,
+    pub minor_image_version: u16,
+    pub major_subsystem_version: u16,
+    pub minor_subsystem_version: u16,
+    pub subsystem: u16,
+    pub dll_characteristics: u16,
+    pub size_of_stack_reserve: u64,
+    pub size_of_stack_commit: u64,
+    pub size_of_heap_reserve: u64,
+    pub size_of_heap_commit: u64,
+}
+
+#[derive(Default, Clone, Copy)]
+struct DataDirectory {
+    virtual_address: u32,
+    size: u32,
+}
+
+/// Information required for writing [`pe::ImageSectionHeader`].
+#[allow(missing_docs)]
+#[derive(Debug, Clone)]
+pub struct Section {
+    pub name: [u8; pe::IMAGE_SIZEOF_SHORT_NAME],
+    pub characteristics: u32,
+    pub range: SectionRange,
+}
+
+/// The file range and virtual address range for a section.
+#[allow(missing_docs)]
+#[derive(Debug, Default, Clone, Copy)]
+pub struct SectionRange {
+    pub virtual_address: u32,
+    pub virtual_size: u32,
+    pub file_offset: u32,
+    pub file_size: u32,
+}
+
+struct RelocBlock {
+    virtual_address: u32,
+    count: u32,
+}
+
+impl RelocBlock {
+    fn size(&self) -> u32 {
+        mem::size_of::<pe::ImageBaseRelocation>() as u32 + self.count * mem::size_of::<u16>() as u32
+    }
+}
diff --git a/vendor/object/src/write/string.rs b/vendor/object/src/write/string.rs
new file mode 100644
index 0000000..b23274a
--- /dev/null
+++ b/vendor/object/src/write/string.rs
@@ -0,0 +1,159 @@
+use alloc::vec::Vec;
+
+#[cfg(feature = "std")]
+type IndexSet<K> = indexmap::IndexSet<K>;
+#[cfg(not(feature = "std"))]
+type IndexSet<K> = indexmap::IndexSet<K, hashbrown::hash_map::DefaultHashBuilder>;
+
+/// An identifier for an entry in a string table.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct StringId(usize);
+
+#[derive(Debug, Default)]
+pub(crate) struct StringTable<'a> {
+    strings: IndexSet<&'a [u8]>,
+    offsets: Vec<usize>,
+}
+
+impl<'a> StringTable<'a> {
+    /// Add a string to the string table.
+    ///
+    /// Panics if the string table has already been written, or
+    /// if the string contains a null byte.
+    pub fn add(&mut self, string: &'a [u8]) -> StringId {
+        assert!(self.offsets.is_empty());
+        assert!(!string.contains(&0));
+        let id = self.strings.insert_full(string).0;
+        StringId(id)
+    }
+
+    /// Return the id of the given string.
+    ///
+    /// Panics if the string is not in the string table.
+    pub fn get_id(&self, string: &[u8]) -> StringId {
+        let id = self.strings.get_index_of(string).unwrap();
+        StringId(id)
+    }
+
+    /// Return the string for the given id.
+    ///
+    /// Panics if the string is not in the string table.
+    pub fn get_string(&self, id: StringId) -> &'a [u8] {
+        self.strings.get_index(id.0).unwrap()
+    }
+
+    /// Return the offset of the given string.
+    ///
+    /// Panics if the string table has not been written, or
+    /// if the string is not in the string table.
+    pub fn get_offset(&self, id: StringId) -> usize {
+        self.offsets[id.0]
+    }
+
+    /// Append the string table to the given `Vec`, and
+    /// calculate the list of string offsets.
+    ///
+    /// `base` is the initial string table offset. For example,
+    /// this should be 1 for ELF, to account for the initial
+    /// null byte (which must have been written by the caller).
+    pub fn write(&mut self, base: usize, w: &mut Vec<u8>) {
+        assert!(self.offsets.is_empty());
+
+        let mut ids: Vec<_> = (0..self.strings.len()).collect();
+        sort(&mut ids, 1, &self.strings);
+
+        self.offsets = vec![0; ids.len()];
+        let mut offset = base;
+        let mut previous = &[][..];
+        for id in ids {
+            let string = self.strings.get_index(id).unwrap();
+            if previous.ends_with(string) {
+                self.offsets[id] = offset - string.len() - 1;
+            } else {
+                self.offsets[id] = offset;
+                w.extend_from_slice(string);
+                w.push(0);
+                offset += string.len() + 1;
+                previous = string;
+            }
+        }
+    }
+}
+
+// Multi-key quicksort.
+//
+// Ordering is such that if a string is a suffix of at least one other string,
+// then it is placed immediately after one of those strings. That is:
+// - comparison starts at the end of the string
+// - shorter strings come later
+//
+// Based on the implementation in LLVM.
+fn sort(mut ids: &mut [usize], mut pos: usize, strings: &IndexSet<&[u8]>) {
+    loop {
+        if ids.len() <= 1 {
+            return;
+        }
+
+        let pivot = byte(ids[0], pos, strings);
+        let mut lower = 0;
+        let mut upper = ids.len();
+        let mut i = 1;
+        while i < upper {
+            let b = byte(ids[i], pos, strings);
+            if b > pivot {
+                ids.swap(lower, i);
+                lower += 1;
+                i += 1;
+            } else if b < pivot {
+                upper -= 1;
+                ids.swap(upper, i);
+            } else {
+                i += 1;
+            }
+        }
+
+        sort(&mut ids[..lower], pos, strings);
+        sort(&mut ids[upper..], pos, strings);
+
+        if pivot == 0 {
+            return;
+        }
+        ids = &mut ids[lower..upper];
+        pos += 1;
+    }
+}
+
+fn byte(id: usize, pos: usize, strings: &IndexSet<&[u8]>) -> u8 {
+    let string = strings.get_index(id).unwrap();
+    let len = string.len();
+    if len >= pos {
+        string[len - pos]
+    } else {
+        // We know the strings don't contain null bytes.
+        0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn string_table() {
+        let mut table = StringTable::default();
+        let id0 = table.add(b"");
+        let id1 = table.add(b"foo");
+        let id2 = table.add(b"bar");
+        let id3 = table.add(b"foobar");
+
+        let mut data = Vec::new();
+        data.push(0);
+        table.write(1, &mut data);
+        assert_eq!(data, b"\0foobar\0foo\0");
+
+        assert_eq!(table.get_offset(id0), 11);
+        assert_eq!(table.get_offset(id1), 8);
+        assert_eq!(table.get_offset(id2), 4);
+        assert_eq!(table.get_offset(id3), 1);
+    }
+}
diff --git a/vendor/object/src/write/util.rs b/vendor/object/src/write/util.rs
new file mode 100644
index 0000000..f7ee2f4
--- /dev/null
+++ b/vendor/object/src/write/util.rs
@@ -0,0 +1,260 @@
+use alloc::vec::Vec;
+#[cfg(feature = "std")]
+use std::{io, mem};
+
+use crate::pod::{bytes_of, bytes_of_slice, Pod};
+
+/// Trait for writable buffer.
+#[allow(clippy::len_without_is_empty)]
+pub trait WritableBuffer {
+    /// Returns position/offset for data to be written at.
+    ///
+    /// Should only be used in debug assertions
+    fn len(&self) -> usize;
+
+    /// Reserves specified number of bytes in the buffer.
+    ///
+    /// This will be called exactly once before writing anything to the buffer,
+    /// and the given size is the exact total number of bytes that will be written.
+    fn reserve(&mut self, size: usize) -> Result<(), ()>;
+
+    /// Writes zero bytes at the end of the buffer until the buffer
+    /// has the specified length.
+    fn resize(&mut self, new_len: usize);
+
+    /// Writes the specified slice of bytes at the end of the buffer.
+    fn write_bytes(&mut self, val: &[u8]);
+
+    /// Writes the specified `Pod` type at the end of the buffer.
+    fn write_pod<T: Pod>(&mut self, val: &T)
+    where
+        Self: Sized,
+    {
+        self.write_bytes(bytes_of(val))
+    }
+
+    /// Writes the specified `Pod` slice at the end of the buffer.
+    fn write_pod_slice<T: Pod>(&mut self, val: &[T])
+    where
+        Self: Sized,
+    {
+        self.write_bytes(bytes_of_slice(val))
+    }
+}
+
+impl<'a> dyn WritableBuffer + 'a {
+    /// Writes the specified `Pod` type at the end of the buffer.
+    pub fn write<T: Pod>(&mut self, val: &T) {
+        self.write_bytes(bytes_of(val))
+    }
+
+    /// Writes the specified `Pod` slice at the end of the buffer.
+    pub fn write_slice<T: Pod>(&mut self, val: &[T]) {
+        self.write_bytes(bytes_of_slice(val))
+    }
+}
+
+impl WritableBuffer for Vec<u8> {
+    #[inline]
+    fn len(&self) -> usize {
+        self.len()
+    }
+
+    #[inline]
+    fn reserve(&mut self, size: usize) -> Result<(), ()> {
+        debug_assert!(self.is_empty());
+        self.reserve(size);
+        Ok(())
+    }
+
+    #[inline]
+    fn resize(&mut self, new_len: usize) {
+        debug_assert!(new_len >= self.len());
+        self.resize(new_len, 0);
+    }
+
+    #[inline]
+    fn write_bytes(&mut self, val: &[u8]) {
+        debug_assert!(self.len() + val.len() <= self.capacity());
+        self.extend_from_slice(val)
+    }
+}
+
+/// A [`WritableBuffer`] that streams data to a [`Write`](std::io::Write) implementation.
+///
+/// [`Self::result`] must be called to determine if an I/O error occurred during writing.
+///
+/// It is advisable to use a buffered writer like [`BufWriter`](std::io::BufWriter)
+/// instead of an unbuffered writer like [`File`](std::fs::File).
+#[cfg(feature = "std")]
+#[derive(Debug)]
+pub struct StreamingBuffer<W> {
+    writer: W,
+    len: usize,
+    result: Result<(), io::Error>,
+}
+
+#[cfg(feature = "std")]
+impl<W> StreamingBuffer<W> {
+    /// Create a new `StreamingBuffer` backed by the given writer.
+    pub fn new(writer: W) -> Self {
+        StreamingBuffer {
+            writer,
+            len: 0,
+            result: Ok(()),
+        }
+    }
+
+    /// Unwraps this [`StreamingBuffer`] giving back the original writer.
+    pub fn into_inner(self) -> W {
+        self.writer
+    }
+
+    /// Returns any error that occurred during writing.
+    pub fn result(&mut self) -> Result<(), io::Error> {
+        mem::replace(&mut self.result, Ok(()))
+    }
+}
+
+#[cfg(feature = "std")]
+impl<W: io::Write> WritableBuffer for StreamingBuffer<W> {
+    #[inline]
+    fn len(&self) -> usize {
+        self.len
+    }
+
+    #[inline]
+    fn reserve(&mut self, _size: usize) -> Result<(), ()> {
+        Ok(())
+    }
+
+    #[inline]
+    fn resize(&mut self, new_len: usize) {
+        debug_assert!(self.len <= new_len);
+        while self.len < new_len {
+            let write_amt = (new_len - self.len - 1) % 1024 + 1;
+            self.write_bytes(&[0; 1024][..write_amt]);
+        }
+    }
+
+    #[inline]
+    fn write_bytes(&mut self, val: &[u8]) {
+        if self.result.is_ok() {
+            self.result = self.writer.write_all(val);
+        }
+        self.len += val.len();
+    }
+}
+
+/// A trait for mutable byte slices.
+///
+/// It provides convenience methods for `Pod` types.
+pub(crate) trait BytesMut {
+    fn write_at<T: Pod>(self, offset: usize, val: &T) -> Result<(), ()>;
+}
+
+impl<'a> BytesMut for &'a mut [u8] {
+    #[inline]
+    fn write_at<T: Pod>(self, offset: usize, val: &T) -> Result<(), ()> {
+        let src = bytes_of(val);
+        let dest = self.get_mut(offset..).ok_or(())?;
+        let dest = dest.get_mut(..src.len()).ok_or(())?;
+        dest.copy_from_slice(src);
+        Ok(())
+    }
+}
+
+/// Write an unsigned number using the LEB128 encoding to a buffer.
+///
+/// Returns the number of bytes written.
+pub(crate) fn write_uleb128(buf: &mut Vec<u8>, mut val: u64) -> usize {
+    let mut len = 0;
+    loop {
+        let mut byte = (val & 0x7f) as u8;
+        val >>= 7;
+        let done = val == 0;
+        if !done {
+            byte |= 0x80;
+        }
+
+        buf.push(byte);
+        len += 1;
+
+        if done {
+            return len;
+        }
+    }
+}
+
+/// Write a signed number using the LEB128 encoding to a buffer.
+///
+/// Returns the number of bytes written.
+#[allow(dead_code)]
+pub(crate) fn write_sleb128(buf: &mut Vec<u8>, mut val: i64) -> usize {
+    let mut len = 0;
+    loop {
+        let mut byte = val as u8;
+        // Keep the sign bit for testing
+        val >>= 6;
+        let done = val == 0 || val == -1;
+        if done {
+            byte &= !0x80;
+        } else {
+            // Remove the sign bit
+            val >>= 1;
+            byte |= 0x80;
+        }
+
+        buf.push(byte);
+        len += 1;
+
+        if done {
+            return len;
+        }
+    }
+}
+
+pub(crate) fn align(offset: usize, size: usize) -> usize {
+    (offset + (size - 1)) & !(size - 1)
+}
+
+#[allow(dead_code)]
+pub(crate) fn align_u32(offset: u32, size: u32) -> u32 {
+    (offset + (size - 1)) & !(size - 1)
+}
+
+#[allow(dead_code)]
+pub(crate) fn align_u64(offset: u64, size: u64) -> u64 {
+    (offset + (size - 1)) & !(size - 1)
+}
+
+pub(crate) fn write_align(buffer: &mut dyn WritableBuffer, size: usize) {
+    let new_len = align(buffer.len(), size);
+    buffer.resize(new_len);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn bytes_mut() {
+        let data = vec![0x01, 0x23, 0x45, 0x67];
+
+        let mut bytes = data.clone();
+        bytes.extend_from_slice(bytes_of(&u16::to_be(0x89ab)));
+        assert_eq!(bytes, [0x01, 0x23, 0x45, 0x67, 0x89, 0xab]);
+
+        let mut bytes = data.clone();
+        assert_eq!(bytes.write_at(0, &u16::to_be(0x89ab)), Ok(()));
+        assert_eq!(bytes, [0x89, 0xab, 0x45, 0x67]);
+
+        let mut bytes = data.clone();
+        assert_eq!(bytes.write_at(2, &u16::to_be(0x89ab)), Ok(()));
+        assert_eq!(bytes, [0x01, 0x23, 0x89, 0xab]);
+
+        assert_eq!(bytes.write_at(3, &u16::to_be(0x89ab)), Err(()));
+        assert_eq!(bytes.write_at(4, &u16::to_be(0x89ab)), Err(()));
+        assert_eq!(vec![].write_at(0, &u32::to_be(0x89ab)), Err(()));
+    }
+}
diff --git a/vendor/object/src/write/xcoff.rs b/vendor/object/src/write/xcoff.rs
new file mode 100644
index 0000000..fc58886
--- /dev/null
+++ b/vendor/object/src/write/xcoff.rs
@@ -0,0 +1,556 @@
+use core::mem;
+
+use crate::endian::{BigEndian as BE, I16, U16, U32};
+use crate::write::string::*;
+use crate::write::util::*;
+use crate::write::*;
+
+use crate::{xcoff, AddressSize};
+
+#[derive(Default, Clone, Copy)]
+struct SectionOffsets {
+    address: u64,
+    data_offset: usize,
+    reloc_offset: usize,
+}
+
+#[derive(Default, Clone, Copy)]
+struct SymbolOffsets {
+    index: usize,
+    str_id: Option<StringId>,
+    aux_count: u8,
+    storage_class: u8,
+}
+
+impl<'a> Object<'a> {
+    pub(crate) fn xcoff_section_info(
+        &self,
+        section: StandardSection,
+    ) -> (&'static [u8], &'static [u8], SectionKind, SectionFlags) {
+        match section {
+            StandardSection::Text => (&[], &b".text"[..], SectionKind::Text, SectionFlags::None),
+            StandardSection::Data => (&[], &b".data"[..], SectionKind::Data, SectionFlags::None),
+            StandardSection::ReadOnlyData
+            | StandardSection::ReadOnlyDataWithRel
+            | StandardSection::ReadOnlyString => (
+                &[],
+                &b".rdata"[..],
+                SectionKind::ReadOnlyData,
+                SectionFlags::None,
+            ),
+            StandardSection::UninitializedData => (
+                &[],
+                &b".bss"[..],
+                SectionKind::UninitializedData,
+                SectionFlags::None,
+            ),
+            StandardSection::Tls => (&[], &b".tdata"[..], SectionKind::Tls, SectionFlags::None),
+            StandardSection::UninitializedTls => (
+                &[],
+                &b".tbss"[..],
+                SectionKind::UninitializedTls,
+                SectionFlags::None,
+            ),
+            StandardSection::TlsVariables => {
+                // Unsupported section.
+                (&[], &[], SectionKind::TlsVariables, SectionFlags::None)
+            }
+            StandardSection::Common => {
+                // Unsupported section.
+                (&[], &[], SectionKind::Common, SectionFlags::None)
+            }
+            StandardSection::GnuProperty => {
+                // Unsupported section.
+                (&[], &[], SectionKind::Note, SectionFlags::None)
+            }
+        }
+    }
+
+    pub(crate) fn xcoff_fixup_relocation(&mut self, relocation: &mut Relocation) -> i64 {
+        let constant = match relocation.kind {
+            RelocationKind::Relative => relocation.addend + 4,
+            _ => relocation.addend,
+        };
+        relocation.addend -= constant;
+        constant
+    }
+
+    pub(crate) fn xcoff_write(&self, buffer: &mut dyn WritableBuffer) -> Result<()> {
+        let is_64 = match self.architecture.address_size().unwrap() {
+            AddressSize::U8 | AddressSize::U16 | AddressSize::U32 => false,
+            AddressSize::U64 => true,
+        };
+
+        let (hdr_size, sechdr_size, rel_size, sym_size) = if is_64 {
+            (
+                mem::size_of::<xcoff::FileHeader64>(),
+                mem::size_of::<xcoff::SectionHeader64>(),
+                mem::size_of::<xcoff::Rel64>(),
+                mem::size_of::<xcoff::Symbol64>(),
+            )
+        } else {
+            (
+                mem::size_of::<xcoff::FileHeader32>(),
+                mem::size_of::<xcoff::SectionHeader32>(),
+                mem::size_of::<xcoff::Rel32>(),
+                mem::size_of::<xcoff::Symbol32>(),
+            )
+        };
+
+        // Calculate offsets and build strtab.
+        let mut offset = 0;
+        let mut strtab = StringTable::default();
+        // We place the shared address 0 immediately after the section header table.
+        let mut address = 0;
+
+        // XCOFF file header.
+        offset += hdr_size;
+        // Section headers.
+        offset += self.sections.len() * sechdr_size;
+
+        // Calculate size of section data.
+        let mut section_offsets = vec![SectionOffsets::default(); self.sections.len()];
+        for (index, section) in self.sections.iter().enumerate() {
+            let len = section.data.len();
+            let sectype = section.kind;
+            // Section address should be 0 for all sections except the .text, .data, and .bss sections.
+            if sectype == SectionKind::Data
+                || sectype == SectionKind::Text
+                || sectype == SectionKind::UninitializedData
+            {
+                section_offsets[index].address = address as u64;
+                address += len;
+                address = align(address, 4);
+            } else {
+                section_offsets[index].address = 0;
+            }
+            if len != 0 {
+                // Set the default section alignment as 4.
+                offset = align(offset, 4);
+                section_offsets[index].data_offset = offset;
+                offset += len;
+            } else {
+                section_offsets[index].data_offset = 0;
+            }
+        }
+
+        // Calculate size of relocations.
+        for (index, section) in self.sections.iter().enumerate() {
+            let count = section.relocations.len();
+            if count != 0 {
+                section_offsets[index].reloc_offset = offset;
+                offset += count * rel_size;
+            } else {
+                section_offsets[index].reloc_offset = 0;
+            }
+        }
+
+        // Calculate size of symbols.
+        let mut file_str_id = None;
+        let mut symbol_offsets = vec![SymbolOffsets::default(); self.symbols.len()];
+        let mut symtab_count = 0;
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            symbol_offsets[index].index = symtab_count;
+            symtab_count += 1;
+
+            let storage_class = if let SymbolFlags::Xcoff { n_sclass, .. } = symbol.flags {
+                n_sclass
+            } else {
+                match symbol.kind {
+                    SymbolKind::Null => xcoff::C_NULL,
+                    SymbolKind::File => xcoff::C_FILE,
+                    SymbolKind::Text | SymbolKind::Data | SymbolKind::Tls => {
+                        if symbol.is_local() {
+                            xcoff::C_STAT
+                        } else if symbol.weak {
+                            xcoff::C_WEAKEXT
+                        } else {
+                            xcoff::C_EXT
+                        }
+                    }
+                    SymbolKind::Section | SymbolKind::Label | SymbolKind::Unknown => {
+                        return Err(Error(format!(
+                            "unimplemented symbol `{}` kind {:?}",
+                            symbol.name().unwrap_or(""),
+                            symbol.kind
+                        )));
+                    }
+                }
+            };
+            symbol_offsets[index].storage_class = storage_class;
+
+            if storage_class == xcoff::C_FILE {
+                if is_64 && file_str_id.is_none() {
+                    file_str_id = Some(strtab.add(b".file"));
+                }
+                if symbol.name.len() > 8 {
+                    symbol_offsets[index].str_id = Some(strtab.add(&symbol.name));
+                }
+            } else if is_64 || symbol.name.len() > 8 {
+                symbol_offsets[index].str_id = Some(strtab.add(&symbol.name));
+            }
+
+            symbol_offsets[index].aux_count = 0;
+            match storage_class {
+                xcoff::C_FILE => {
+                    symbol_offsets[index].aux_count = 1;
+                    symtab_count += 1;
+                }
+                xcoff::C_EXT | xcoff::C_WEAKEXT | xcoff::C_HIDEXT => {
+                    symbol_offsets[index].aux_count = 1;
+                    symtab_count += 1;
+                }
+                // TODO: support auxiliary entry for other types of symbol.
+                _ => {}
+            }
+        }
+        let symtab_offset = offset;
+        let symtab_len = symtab_count * sym_size;
+        offset += symtab_len;
+
+        // Calculate size of strtab.
+        let strtab_offset = offset;
+        let mut strtab_data = Vec::new();
+        // First 4 bytes of strtab are the length.
+        strtab.write(4, &mut strtab_data);
+        let strtab_len = strtab_data.len() + 4;
+        offset += strtab_len;
+
+        // Start writing.
+        buffer
+            .reserve(offset)
+            .map_err(|_| Error(String::from("Cannot allocate buffer")))?;
+
+        // Write file header.
+        if is_64 {
+            let header = xcoff::FileHeader64 {
+                f_magic: U16::new(BE, xcoff::MAGIC_64),
+                f_nscns: U16::new(BE, self.sections.len() as u16),
+                f_timdat: U32::new(BE, 0),
+                f_symptr: U64::new(BE, symtab_offset as u64),
+                f_nsyms: U32::new(BE, symtab_count as u32),
+                f_opthdr: U16::new(BE, 0),
+                f_flags: match self.flags {
+                    FileFlags::Xcoff { f_flags } => U16::new(BE, f_flags),
+                    _ => U16::default(),
+                },
+            };
+            buffer.write(&header);
+        } else {
+            let header = xcoff::FileHeader32 {
+                f_magic: U16::new(BE, xcoff::MAGIC_32),
+                f_nscns: U16::new(BE, self.sections.len() as u16),
+                f_timdat: U32::new(BE, 0),
+                f_symptr: U32::new(BE, symtab_offset as u32),
+                f_nsyms: U32::new(BE, symtab_count as u32),
+                f_opthdr: U16::new(BE, 0),
+                f_flags: match self.flags {
+                    FileFlags::Xcoff { f_flags } => U16::new(BE, f_flags),
+                    _ => U16::default(),
+                },
+            };
+            buffer.write(&header);
+        }
+
+        // Write section headers.
+        for (index, section) in self.sections.iter().enumerate() {
+            let mut sectname = [0; 8];
+            sectname
+                .get_mut(..section.name.len())
+                .ok_or_else(|| {
+                    Error(format!(
+                        "section name `{}` is too long",
+                        section.name().unwrap_or(""),
+                    ))
+                })?
+                .copy_from_slice(&section.name);
+            let flags = if let SectionFlags::Xcoff { s_flags } = section.flags {
+                s_flags
+            } else {
+                match section.kind {
+                    SectionKind::Text
+                    | SectionKind::ReadOnlyData
+                    | SectionKind::ReadOnlyString
+                    | SectionKind::ReadOnlyDataWithRel => xcoff::STYP_TEXT,
+                    SectionKind::Data => xcoff::STYP_DATA,
+                    SectionKind::UninitializedData => xcoff::STYP_BSS,
+                    SectionKind::Tls => xcoff::STYP_TDATA,
+                    SectionKind::UninitializedTls => xcoff::STYP_TBSS,
+                    SectionKind::OtherString => xcoff::STYP_INFO,
+                    SectionKind::Debug => xcoff::STYP_DEBUG,
+                    SectionKind::Other | SectionKind::Metadata => 0,
+                    SectionKind::Note
+                    | SectionKind::Linker
+                    | SectionKind::Common
+                    | SectionKind::Unknown
+                    | SectionKind::TlsVariables
+                    | SectionKind::Elf(_) => {
+                        return Err(Error(format!(
+                            "unimplemented section `{}` kind {:?}",
+                            section.name().unwrap_or(""),
+                            section.kind
+                        )));
+                    }
+                }
+                .into()
+            };
+            if is_64 {
+                let section_header = xcoff::SectionHeader64 {
+                    s_name: sectname,
+                    s_paddr: U64::new(BE, section_offsets[index].address),
+                    // This field has the same value as the s_paddr field.
+                    s_vaddr: U64::new(BE, section_offsets[index].address),
+                    s_size: U64::new(BE, section.data.len() as u64),
+                    s_scnptr: U64::new(BE, section_offsets[index].data_offset as u64),
+                    s_relptr: U64::new(BE, section_offsets[index].reloc_offset as u64),
+                    s_lnnoptr: U64::new(BE, 0),
+                    s_nreloc: U32::new(BE, section.relocations.len() as u32),
+                    s_nlnno: U32::new(BE, 0),
+                    s_flags: U32::new(BE, flags),
+                    s_reserve: U32::new(BE, 0),
+                };
+                buffer.write(&section_header);
+            } else {
+                let section_header = xcoff::SectionHeader32 {
+                    s_name: sectname,
+                    s_paddr: U32::new(BE, section_offsets[index].address as u32),
+                    // This field has the same value as the s_paddr field.
+                    s_vaddr: U32::new(BE, section_offsets[index].address as u32),
+                    s_size: U32::new(BE, section.data.len() as u32),
+                    s_scnptr: U32::new(BE, section_offsets[index].data_offset as u32),
+                    s_relptr: U32::new(BE, section_offsets[index].reloc_offset as u32),
+                    s_lnnoptr: U32::new(BE, 0),
+                    // TODO: If more than 65,534 relocation entries are required, the field
+                    // value will be 65535, and an STYP_OVRFLO section header will contain
+                    // the actual count of relocation entries in the s_paddr field.
+                    s_nreloc: U16::new(BE, section.relocations.len() as u16),
+                    s_nlnno: U16::new(BE, 0),
+                    s_flags: U32::new(BE, flags),
+                };
+                buffer.write(&section_header);
+            }
+        }
+
+        // Write section data.
+        for (index, section) in self.sections.iter().enumerate() {
+            let len = section.data.len();
+            if len != 0 {
+                write_align(buffer, 4);
+                debug_assert_eq!(section_offsets[index].data_offset, buffer.len());
+                buffer.write_bytes(&section.data);
+            }
+        }
+
+        // Write relocations.
+        for (index, section) in self.sections.iter().enumerate() {
+            if !section.relocations.is_empty() {
+                debug_assert_eq!(section_offsets[index].reloc_offset, buffer.len());
+                for reloc in &section.relocations {
+                    let rtype = match reloc.kind {
+                        RelocationKind::Absolute => xcoff::R_POS,
+                        RelocationKind::Relative => xcoff::R_REL,
+                        RelocationKind::Got => xcoff::R_TOC,
+                        RelocationKind::Xcoff(x) => x,
+                        _ => {
+                            return Err(Error(format!("unimplemented relocation {:?}", reloc)));
+                        }
+                    };
+                    if is_64 {
+                        let xcoff_rel = xcoff::Rel64 {
+                            r_vaddr: U64::new(BE, reloc.offset),
+                            r_symndx: U32::new(BE, symbol_offsets[reloc.symbol.0].index as u32),
+                            // Specifies the bit length of the relocatable reference minus one.
+                            r_rsize: (reloc.size - 1),
+                            r_rtype: rtype,
+                        };
+                        buffer.write(&xcoff_rel);
+                    } else {
+                        let xcoff_rel = xcoff::Rel32 {
+                            r_vaddr: U32::new(BE, reloc.offset as u32),
+                            r_symndx: U32::new(BE, symbol_offsets[reloc.symbol.0].index as u32),
+                            r_rsize: (reloc.size - 1),
+                            r_rtype: rtype,
+                        };
+                        buffer.write(&xcoff_rel);
+                    }
+                }
+            }
+        }
+
+        // Write symbols.
+        debug_assert_eq!(symtab_offset, buffer.len());
+        for (index, symbol) in self.symbols.iter().enumerate() {
+            let (n_value, section_kind) = if let SymbolSection::Section(id) = symbol.section {
+                (
+                    section_offsets[id.0].address + symbol.value,
+                    self.sections[id.0].kind,
+                )
+            } else {
+                (symbol.value, SectionKind::Unknown)
+            };
+            let n_scnum = match symbol.section {
+                SymbolSection::None => {
+                    debug_assert_eq!(symbol.kind, SymbolKind::File);
+                    xcoff::N_DEBUG
+                }
+                SymbolSection::Undefined | SymbolSection::Common => xcoff::N_UNDEF,
+                SymbolSection::Absolute => xcoff::N_ABS,
+                SymbolSection::Section(id) => id.0 as i16 + 1,
+            };
+            let n_sclass = symbol_offsets[index].storage_class;
+            let n_type = if (symbol.scope == SymbolScope::Linkage)
+                && (n_sclass == xcoff::C_EXT
+                    || n_sclass == xcoff::C_WEAKEXT
+                    || n_sclass == xcoff::C_HIDEXT)
+            {
+                xcoff::SYM_V_HIDDEN
+            } else {
+                0
+            };
+            let n_numaux = symbol_offsets[index].aux_count;
+            if is_64 {
+                let str_id = if n_sclass == xcoff::C_FILE {
+                    file_str_id.unwrap()
+                } else {
+                    symbol_offsets[index].str_id.unwrap()
+                };
+                let xcoff_sym = xcoff::Symbol64 {
+                    n_value: U64::new(BE, n_value),
+                    n_offset: U32::new(BE, strtab.get_offset(str_id) as u32),
+                    n_scnum: I16::new(BE, n_scnum),
+                    n_type: U16::new(BE, n_type),
+                    n_sclass,
+                    n_numaux,
+                };
+                buffer.write(&xcoff_sym);
+            } else {
+                let mut sym_name = [0; 8];
+                if n_sclass == xcoff::C_FILE {
+                    sym_name[..5].copy_from_slice(b".file");
+                } else if symbol.name.len() <= 8 {
+                    sym_name[..symbol.name.len()].copy_from_slice(&symbol.name[..]);
+                } else {
+                    let str_offset = strtab.get_offset(symbol_offsets[index].str_id.unwrap());
+                    sym_name[4..8].copy_from_slice(&u32::to_be_bytes(str_offset as u32));
+                }
+                let xcoff_sym = xcoff::Symbol32 {
+                    n_name: sym_name,
+                    n_value: U32::new(BE, n_value as u32),
+                    n_scnum: I16::new(BE, n_scnum),
+                    n_type: U16::new(BE, n_type),
+                    n_sclass,
+                    n_numaux,
+                };
+                buffer.write(&xcoff_sym);
+            }
+            // Generate auxiliary entries.
+            if n_sclass == xcoff::C_FILE {
+                debug_assert_eq!(n_numaux, 1);
+                let mut x_fname = [0; 8];
+                if symbol.name.len() <= 8 {
+                    x_fname[..symbol.name.len()].copy_from_slice(&symbol.name[..]);
+                } else {
+                    let str_offset = strtab.get_offset(symbol_offsets[index].str_id.unwrap());
+                    x_fname[4..8].copy_from_slice(&u32::to_be_bytes(str_offset as u32));
+                }
+                if is_64 {
+                    let file_aux = xcoff::FileAux64 {
+                        x_fname,
+                        x_fpad: Default::default(),
+                        x_ftype: xcoff::XFT_FN,
+                        x_freserve: Default::default(),
+                        x_auxtype: xcoff::AUX_FILE,
+                    };
+                    buffer.write(&file_aux);
+                } else {
+                    let file_aux = xcoff::FileAux32 {
+                        x_fname,
+                        x_fpad: Default::default(),
+                        x_ftype: xcoff::XFT_FN,
+                        x_freserve: Default::default(),
+                    };
+                    buffer.write(&file_aux);
+                }
+            } else if n_sclass == xcoff::C_EXT
+                || n_sclass == xcoff::C_WEAKEXT
+                || n_sclass == xcoff::C_HIDEXT
+            {
+                debug_assert_eq!(n_numaux, 1);
+                let (x_smtyp, x_smclas) = if let SymbolFlags::Xcoff {
+                    x_smtyp, x_smclas, ..
+                } = symbol.flags
+                {
+                    (x_smtyp, x_smclas)
+                } else {
+                    match symbol.kind {
+                        SymbolKind::Text => (xcoff::XTY_SD, xcoff::XMC_PR),
+                        SymbolKind::Data => {
+                            if section_kind == SectionKind::UninitializedData {
+                                (xcoff::XTY_CM, xcoff::XMC_BS)
+                            } else if section_kind == SectionKind::ReadOnlyData {
+                                (xcoff::XTY_SD, xcoff::XMC_RO)
+                            } else {
+                                (xcoff::XTY_SD, xcoff::XMC_RW)
+                            }
+                        }
+                        SymbolKind::Tls => {
+                            if section_kind == SectionKind::UninitializedTls {
+                                (xcoff::XTY_CM, xcoff::XMC_UL)
+                            } else {
+                                (xcoff::XTY_SD, xcoff::XMC_TL)
+                            }
+                        }
+                        _ => {
+                            return Err(Error(format!(
+                                "unimplemented symbol `{}` kind {:?}",
+                                symbol.name().unwrap_or(""),
+                                symbol.kind
+                            )));
+                        }
+                    }
+                };
+                let scnlen = if let SymbolFlags::Xcoff {
+                    containing_csect: Some(containing_csect),
+                    ..
+                } = symbol.flags
+                {
+                    symbol_offsets[containing_csect.0].index as u64
+                } else {
+                    symbol.size
+                };
+                if is_64 {
+                    let csect_aux = xcoff::CsectAux64 {
+                        x_scnlen_lo: U32::new(BE, (scnlen & 0xFFFFFFFF) as u32),
+                        x_scnlen_hi: U32::new(BE, ((scnlen >> 32) & 0xFFFFFFFF) as u32),
+                        x_parmhash: U32::new(BE, 0),
+                        x_snhash: U16::new(BE, 0),
+                        x_smtyp,
+                        x_smclas,
+                        pad: 0,
+                        x_auxtype: xcoff::AUX_CSECT,
+                    };
+                    buffer.write(&csect_aux);
+                } else {
+                    let csect_aux = xcoff::CsectAux32 {
+                        x_scnlen: U32::new(BE, scnlen as u32),
+                        x_parmhash: U32::new(BE, 0),
+                        x_snhash: U16::new(BE, 0),
+                        x_smtyp,
+                        x_smclas,
+                        x_stab: U32::new(BE, 0),
+                        x_snstab: U16::new(BE, 0),
+                    };
+                    buffer.write(&csect_aux);
+                }
+            }
+        }
+
+        // Write string table.
+        debug_assert_eq!(strtab_offset, buffer.len());
+        buffer.write_bytes(&u32::to_be_bytes(strtab_len as u32));
+        buffer.write_bytes(&strtab_data);
+
+        debug_assert_eq!(offset, buffer.len());
+        Ok(())
+    }
+}