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Diffstat (limited to 'vendor/gimli/src/write/writer.rs')
| -rw-r--r-- | vendor/gimli/src/write/writer.rs | 494 |
1 files changed, 494 insertions, 0 deletions
diff --git a/vendor/gimli/src/write/writer.rs b/vendor/gimli/src/write/writer.rs new file mode 100644 index 0000000..1ce3641 --- /dev/null +++ b/vendor/gimli/src/write/writer.rs @@ -0,0 +1,494 @@ +use crate::common::{Format, SectionId}; +use crate::constants; +use crate::endianity::Endianity; +use crate::leb128; +use crate::write::{Address, Error, Result}; + +/// A trait for writing the data to a DWARF section. +/// +/// All write operations append to the section unless otherwise specified. +#[allow(clippy::len_without_is_empty)] +pub trait Writer { + /// The endianity of bytes that are written. + type Endian: Endianity; + + /// Return the endianity of bytes that are written. + fn endian(&self) -> Self::Endian; + + /// Return the current section length. + /// + /// This may be used as an offset for future `write_at` calls. + fn len(&self) -> usize; + + /// Write a slice. + fn write(&mut self, bytes: &[u8]) -> Result<()>; + + /// Write a slice at a given offset. + /// + /// The write must not extend past the current section length. + fn write_at(&mut self, offset: usize, bytes: &[u8]) -> Result<()>; + + /// Write an address. + /// + /// If the writer supports relocations, then it must provide its own implementation + /// of this method. + // TODO: use write_reference instead? + fn write_address(&mut self, address: Address, size: u8) -> Result<()> { + match address { + Address::Constant(val) => self.write_udata(val, size), + Address::Symbol { .. } => Err(Error::InvalidAddress), + } + } + + /// Write an address with a `.eh_frame` pointer encoding. + /// + /// The given size is only used for `DW_EH_PE_absptr` formats. + /// + /// If the writer supports relocations, then it must provide its own implementation + /// of this method. + fn write_eh_pointer( + &mut self, + address: Address, + eh_pe: constants::DwEhPe, + size: u8, + ) -> Result<()> { + match address { + Address::Constant(val) => { + // Indirect doesn't matter here. + let val = match eh_pe.application() { + constants::DW_EH_PE_absptr => val, + constants::DW_EH_PE_pcrel => { + // TODO: better handling of sign + let offset = self.len() as u64; + val.wrapping_sub(offset) + } + _ => { + return Err(Error::UnsupportedPointerEncoding(eh_pe)); + } + }; + self.write_eh_pointer_data(val, eh_pe.format(), size) + } + Address::Symbol { .. } => Err(Error::InvalidAddress), + } + } + + /// Write a value with a `.eh_frame` pointer format. + /// + /// The given size is only used for `DW_EH_PE_absptr` formats. + /// + /// This must not be used directly for values that may require relocation. + fn write_eh_pointer_data( + &mut self, + val: u64, + format: constants::DwEhPe, + size: u8, + ) -> Result<()> { + match format { + constants::DW_EH_PE_absptr => self.write_udata(val, size), + constants::DW_EH_PE_uleb128 => self.write_uleb128(val), + constants::DW_EH_PE_udata2 => self.write_udata(val, 2), + constants::DW_EH_PE_udata4 => self.write_udata(val, 4), + constants::DW_EH_PE_udata8 => self.write_udata(val, 8), + constants::DW_EH_PE_sleb128 => self.write_sleb128(val as i64), + constants::DW_EH_PE_sdata2 => self.write_sdata(val as i64, 2), + constants::DW_EH_PE_sdata4 => self.write_sdata(val as i64, 4), + constants::DW_EH_PE_sdata8 => self.write_sdata(val as i64, 8), + _ => Err(Error::UnsupportedPointerEncoding(format)), + } + } + + /// Write an offset that is relative to the start of the given section. + /// + /// If the writer supports relocations, then it must provide its own implementation + /// of this method. + fn write_offset(&mut self, val: usize, _section: SectionId, size: u8) -> Result<()> { + self.write_udata(val as u64, size) + } + + /// Write an offset that is relative to the start of the given section. + /// + /// If the writer supports relocations, then it must provide its own implementation + /// of this method. + fn write_offset_at( + &mut self, + offset: usize, + val: usize, + _section: SectionId, + size: u8, + ) -> Result<()> { + self.write_udata_at(offset, val as u64, size) + } + + /// Write a reference to a symbol. + /// + /// If the writer supports symbols, then it must provide its own implementation + /// of this method. + fn write_reference(&mut self, _symbol: usize, _size: u8) -> Result<()> { + Err(Error::InvalidReference) + } + + /// Write a u8. + fn write_u8(&mut self, val: u8) -> Result<()> { + let bytes = [val]; + self.write(&bytes) + } + + /// Write a u16. + fn write_u16(&mut self, val: u16) -> Result<()> { + let mut bytes = [0; 2]; + self.endian().write_u16(&mut bytes, val); + self.write(&bytes) + } + + /// Write a u32. + fn write_u32(&mut self, val: u32) -> Result<()> { + let mut bytes = [0; 4]; + self.endian().write_u32(&mut bytes, val); + self.write(&bytes) + } + + /// Write a u64. + fn write_u64(&mut self, val: u64) -> Result<()> { + let mut bytes = [0; 8]; + self.endian().write_u64(&mut bytes, val); + self.write(&bytes) + } + + /// Write a u8 at the given offset. + fn write_u8_at(&mut self, offset: usize, val: u8) -> Result<()> { + let bytes = [val]; + self.write_at(offset, &bytes) + } + + /// Write a u16 at the given offset. + fn write_u16_at(&mut self, offset: usize, val: u16) -> Result<()> { + let mut bytes = [0; 2]; + self.endian().write_u16(&mut bytes, val); + self.write_at(offset, &bytes) + } + + /// Write a u32 at the given offset. + fn write_u32_at(&mut self, offset: usize, val: u32) -> Result<()> { + let mut bytes = [0; 4]; + self.endian().write_u32(&mut bytes, val); + self.write_at(offset, &bytes) + } + + /// Write a u64 at the given offset. + fn write_u64_at(&mut self, offset: usize, val: u64) -> Result<()> { + let mut bytes = [0; 8]; + self.endian().write_u64(&mut bytes, val); + self.write_at(offset, &bytes) + } + + /// Write unsigned data of the given size. + /// + /// Returns an error if the value is too large for the size. + /// This must not be used directly for values that may require relocation. + fn write_udata(&mut self, val: u64, size: u8) -> Result<()> { + match size { + 1 => { + let write_val = val as u8; + if val != u64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u8(write_val) + } + 2 => { + let write_val = val as u16; + if val != u64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u16(write_val) + } + 4 => { + let write_val = val as u32; + if val != u64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u32(write_val) + } + 8 => self.write_u64(val), + otherwise => Err(Error::UnsupportedWordSize(otherwise)), + } + } + + /// Write signed data of the given size. + /// + /// Returns an error if the value is too large for the size. + /// This must not be used directly for values that may require relocation. + fn write_sdata(&mut self, val: i64, size: u8) -> Result<()> { + match size { + 1 => { + let write_val = val as i8; + if val != i64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u8(write_val as u8) + } + 2 => { + let write_val = val as i16; + if val != i64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u16(write_val as u16) + } + 4 => { + let write_val = val as i32; + if val != i64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u32(write_val as u32) + } + 8 => self.write_u64(val as u64), + otherwise => Err(Error::UnsupportedWordSize(otherwise)), + } + } + + /// Write a word of the given size at the given offset. + /// + /// Returns an error if the value is too large for the size. + /// This must not be used directly for values that may require relocation. + fn write_udata_at(&mut self, offset: usize, val: u64, size: u8) -> Result<()> { + match size { + 1 => { + let write_val = val as u8; + if val != u64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u8_at(offset, write_val) + } + 2 => { + let write_val = val as u16; + if val != u64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u16_at(offset, write_val) + } + 4 => { + let write_val = val as u32; + if val != u64::from(write_val) { + return Err(Error::ValueTooLarge); + } + self.write_u32_at(offset, write_val) + } + 8 => self.write_u64_at(offset, val), + otherwise => Err(Error::UnsupportedWordSize(otherwise)), + } + } + + /// Write an unsigned LEB128 encoded integer. + fn write_uleb128(&mut self, val: u64) -> Result<()> { + let mut bytes = [0u8; 10]; + // bytes is long enough so this will never fail. + let len = leb128::write::unsigned(&mut { &mut bytes[..] }, val).unwrap(); + self.write(&bytes[..len]) + } + + /// Read an unsigned LEB128 encoded integer. + fn write_sleb128(&mut self, val: i64) -> Result<()> { + let mut bytes = [0u8; 10]; + // bytes is long enough so this will never fail. + let len = leb128::write::signed(&mut { &mut bytes[..] }, val).unwrap(); + self.write(&bytes[..len]) + } + + /// Write an initial length according to the given DWARF format. + /// + /// This will only write a length of zero, since the length isn't + /// known yet, and a subsequent call to `write_initial_length_at` + /// will write the actual length. + fn write_initial_length(&mut self, format: Format) -> Result<InitialLengthOffset> { + if format == Format::Dwarf64 { + self.write_u32(0xffff_ffff)?; + } + let offset = InitialLengthOffset(self.len()); + self.write_udata(0, format.word_size())?; + Ok(offset) + } + + /// Write an initial length at the given offset according to the given DWARF format. + /// + /// `write_initial_length` must have previously returned the offset. + fn write_initial_length_at( + &mut self, + offset: InitialLengthOffset, + length: u64, + format: Format, + ) -> Result<()> { + self.write_udata_at(offset.0, length, format.word_size()) + } +} + +/// The offset at which an initial length should be written. +#[derive(Debug, Clone, Copy)] +pub struct InitialLengthOffset(usize); + +#[cfg(test)] +mod tests { + use super::*; + use crate::write; + use crate::{BigEndian, LittleEndian}; + use std::{i64, u64}; + + #[test] + fn test_writer() { + let mut w = write::EndianVec::new(LittleEndian); + w.write_address(Address::Constant(0x1122_3344), 4).unwrap(); + assert_eq!(w.slice(), &[0x44, 0x33, 0x22, 0x11]); + assert_eq!( + w.write_address( + Address::Symbol { + symbol: 0, + addend: 0 + }, + 4 + ), + Err(Error::InvalidAddress) + ); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_offset(0x1122_3344, SectionId::DebugInfo, 4) + .unwrap(); + assert_eq!(w.slice(), &[0x44, 0x33, 0x22, 0x11]); + w.write_offset_at(1, 0x5566, SectionId::DebugInfo, 2) + .unwrap(); + assert_eq!(w.slice(), &[0x44, 0x66, 0x55, 0x11]); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_u8(0x11).unwrap(); + w.write_u16(0x2233).unwrap(); + w.write_u32(0x4455_6677).unwrap(); + w.write_u64(0x8081_8283_8485_8687).unwrap(); + #[rustfmt::skip] + assert_eq!(w.slice(), &[ + 0x11, + 0x33, 0x22, + 0x77, 0x66, 0x55, 0x44, + 0x87, 0x86, 0x85, 0x84, 0x83, 0x82, 0x81, 0x80, + ]); + w.write_u8_at(14, 0x11).unwrap(); + w.write_u16_at(12, 0x2233).unwrap(); + w.write_u32_at(8, 0x4455_6677).unwrap(); + w.write_u64_at(0, 0x8081_8283_8485_8687).unwrap(); + #[rustfmt::skip] + assert_eq!(w.slice(), &[ + 0x87, 0x86, 0x85, 0x84, 0x83, 0x82, 0x81, 0x80, + 0x77, 0x66, 0x55, 0x44, + 0x33, 0x22, + 0x11, + ]); + + let mut w = write::EndianVec::new(BigEndian); + w.write_u8(0x11).unwrap(); + w.write_u16(0x2233).unwrap(); + w.write_u32(0x4455_6677).unwrap(); + w.write_u64(0x8081_8283_8485_8687).unwrap(); + #[rustfmt::skip] + assert_eq!(w.slice(), &[ + 0x11, + 0x22, 0x33, + 0x44, 0x55, 0x66, 0x77, + 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, + ]); + w.write_u8_at(14, 0x11).unwrap(); + w.write_u16_at(12, 0x2233).unwrap(); + w.write_u32_at(8, 0x4455_6677).unwrap(); + w.write_u64_at(0, 0x8081_8283_8485_8687).unwrap(); + #[rustfmt::skip] + assert_eq!(w.slice(), &[ + 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, + 0x44, 0x55, 0x66, 0x77, + 0x22, 0x33, + 0x11, + ]); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_udata(0x11, 1).unwrap(); + w.write_udata(0x2233, 2).unwrap(); + w.write_udata(0x4455_6677, 4).unwrap(); + w.write_udata(0x8081_8283_8485_8687, 8).unwrap(); + #[rustfmt::skip] + assert_eq!(w.slice(), &[ + 0x11, + 0x33, 0x22, + 0x77, 0x66, 0x55, 0x44, + 0x87, 0x86, 0x85, 0x84, 0x83, 0x82, 0x81, 0x80, + ]); + assert_eq!(w.write_udata(0x100, 1), Err(Error::ValueTooLarge)); + assert_eq!(w.write_udata(0x1_0000, 2), Err(Error::ValueTooLarge)); + assert_eq!(w.write_udata(0x1_0000_0000, 4), Err(Error::ValueTooLarge)); + assert_eq!(w.write_udata(0x00, 3), Err(Error::UnsupportedWordSize(3))); + w.write_udata_at(14, 0x11, 1).unwrap(); + w.write_udata_at(12, 0x2233, 2).unwrap(); + w.write_udata_at(8, 0x4455_6677, 4).unwrap(); + w.write_udata_at(0, 0x8081_8283_8485_8687, 8).unwrap(); + #[rustfmt::skip] + assert_eq!(w.slice(), &[ + 0x87, 0x86, 0x85, 0x84, 0x83, 0x82, 0x81, 0x80, + 0x77, 0x66, 0x55, 0x44, + 0x33, 0x22, + 0x11, + ]); + assert_eq!(w.write_udata_at(0, 0x100, 1), Err(Error::ValueTooLarge)); + assert_eq!(w.write_udata_at(0, 0x1_0000, 2), Err(Error::ValueTooLarge)); + assert_eq!( + w.write_udata_at(0, 0x1_0000_0000, 4), + Err(Error::ValueTooLarge) + ); + assert_eq!( + w.write_udata_at(0, 0x00, 3), + Err(Error::UnsupportedWordSize(3)) + ); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_uleb128(0).unwrap(); + assert_eq!(w.slice(), &[0]); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_uleb128(u64::MAX).unwrap(); + assert_eq!( + w.slice(), + &[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 1] + ); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_sleb128(0).unwrap(); + assert_eq!(w.slice(), &[0]); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_sleb128(i64::MAX).unwrap(); + assert_eq!( + w.slice(), + &[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0] + ); + + let mut w = write::EndianVec::new(LittleEndian); + w.write_sleb128(i64::MIN).unwrap(); + assert_eq!( + w.slice(), + &[0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x7f] + ); + + let mut w = write::EndianVec::new(LittleEndian); + let offset = w.write_initial_length(Format::Dwarf32).unwrap(); + assert_eq!(w.slice(), &[0, 0, 0, 0]); + w.write_initial_length_at(offset, 0x1122_3344, Format::Dwarf32) + .unwrap(); + assert_eq!(w.slice(), &[0x44, 0x33, 0x22, 0x11]); + assert_eq!( + w.write_initial_length_at(offset, 0x1_0000_0000, Format::Dwarf32), + Err(Error::ValueTooLarge) + ); + + let mut w = write::EndianVec::new(LittleEndian); + let offset = w.write_initial_length(Format::Dwarf64).unwrap(); + assert_eq!(w.slice(), &[0xff, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0]); + w.write_initial_length_at(offset, 0x1122_3344_5566_7788, Format::Dwarf64) + .unwrap(); + assert_eq!( + w.slice(), + &[0xff, 0xff, 0xff, 0xff, 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11] + ); + } +} |