Initial vendor packages

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

1 files changed, 827 insertions, 0 deletions

diff --git a/vendor/gimli/src/read/mod.rs b/vendor/gimli/src/read/mod.rs
new file mode 100644
index 0000000..2ad7f6a
--- /dev/null
+++ b/vendor/gimli/src/read/mod.rs
@@ -0,0 +1,827 @@
+//! Read DWARF debugging information.
+//!
+//! * [Example Usage](#example-usage)
+//! * [API Structure](#api-structure)
+//! * [Using with `FallibleIterator`](#using-with-fallibleiterator)
+//!
+//! ## Example Usage
+//!
+//! Print out all of the functions in the debuggee program:
+//!
+//! ```rust,no_run
+//! # fn example() -> Result<(), gimli::Error> {
+//! # type R = gimli::EndianSlice<'static, gimli::LittleEndian>;
+//! # let get_file_section_reader = |name| -> Result<R, gimli::Error> { unimplemented!() };
+//! # let get_sup_file_section_reader = |name| -> Result<R, gimli::Error> { unimplemented!() };
+//! // Read the DWARF sections with whatever object loader you're using.
+//! // These closures should return a `Reader` instance (e.g. `EndianSlice`).
+//! let loader = |section: gimli::SectionId| { get_file_section_reader(section.name()) };
+//! let sup_loader = |section: gimli::SectionId| { get_sup_file_section_reader(section.name()) };
+//! let mut dwarf = gimli::Dwarf::load(loader)?;
+//! dwarf.load_sup(sup_loader)?;
+//!
+//! // Iterate over all compilation units.
+//! let mut iter = dwarf.units();
+//! while let Some(header) = iter.next()? {
+//!     // Parse the abbreviations and other information for this compilation unit.
+//!     let unit = dwarf.unit(header)?;
+//!
+//!     // Iterate over all of this compilation unit's entries.
+//!     let mut entries = unit.entries();
+//!     while let Some((_, entry)) = entries.next_dfs()? {
+//!         // If we find an entry for a function, print it.
+//!         if entry.tag() == gimli::DW_TAG_subprogram {
+//!             println!("Found a function: {:?}", entry);
+//!         }
+//!     }
+//! }
+//! # unreachable!()
+//! # }
+//! ```
+//!
+//! Full example programs:
+//!
+//!   * [A simple parser](https://github.com/gimli-rs/gimli/blob/master/crates/examples/src/bin/simple.rs)
+//!
+//!   * [A `dwarfdump`
+//!     clone](https://github.com/gimli-rs/gimli/blob/master/crates/examples/src/bin/dwarfdump.rs)
+//!
+//!   * [An `addr2line` clone](https://github.com/gimli-rs/addr2line)
+//!
+//!   * [`ddbug`](https://github.com/gimli-rs/ddbug), a utility giving insight into
+//!     code generation by making debugging information readable
+//!
+//!   * [`dwprod`](https://github.com/fitzgen/dwprod), a tiny utility to list the
+//!     compilers used to create each compilation unit within a shared library or
+//!     executable (via `DW_AT_producer`)
+//!
+//!   * [`dwarf-validate`](https://github.com/gimli-rs/gimli/blob/master/crates/examples/src/bin/dwarf-validate.rs),
+//!     a program to validate the integrity of some DWARF and its references
+//!     between sections and compilation units.
+//!
+//! ## API Structure
+//!
+//! * Basic familiarity with DWARF is assumed.
+//!
+//! * The [`Dwarf`](./struct.Dwarf.html) type contains the commonly used DWARF
+//! sections. It has methods that simplify access to debugging data that spans
+//! multiple sections. Use of this type is optional, but recommended.
+//!
+//! * Each section gets its own type. Consider these types the entry points to
+//! the library:
+//!
+//!   * [`DebugAbbrev`](./struct.DebugAbbrev.html): The `.debug_abbrev` section.
+//!
+//!   * [`DebugAddr`](./struct.DebugAddr.html): The `.debug_addr` section.
+//!
+//!   * [`DebugAranges`](./struct.DebugAranges.html): The `.debug_aranges`
+//!   section.
+//!
+//!   * [`DebugFrame`](./struct.DebugFrame.html): The `.debug_frame` section.
+//!
+//!   * [`DebugInfo`](./struct.DebugInfo.html): The `.debug_info` section.
+//!
+//!   * [`DebugLine`](./struct.DebugLine.html): The `.debug_line` section.
+//!
+//!   * [`DebugLineStr`](./struct.DebugLineStr.html): The `.debug_line_str` section.
+//!
+//!   * [`DebugLoc`](./struct.DebugLoc.html): The `.debug_loc` section.
+//!
+//!   * [`DebugLocLists`](./struct.DebugLocLists.html): The `.debug_loclists` section.
+//!
+//!   * [`DebugPubNames`](./struct.DebugPubNames.html): The `.debug_pubnames`
+//!   section.
+//!
+//!   * [`DebugPubTypes`](./struct.DebugPubTypes.html): The `.debug_pubtypes`
+//!   section.
+//!
+//!   * [`DebugRanges`](./struct.DebugRanges.html): The `.debug_ranges` section.
+//!
+//!   * [`DebugRngLists`](./struct.DebugRngLists.html): The `.debug_rnglists` section.
+//!
+//!   * [`DebugStr`](./struct.DebugStr.html): The `.debug_str` section.
+//!
+//!   * [`DebugStrOffsets`](./struct.DebugStrOffsets.html): The `.debug_str_offsets` section.
+//!
+//!   * [`DebugTypes`](./struct.DebugTypes.html): The `.debug_types` section.
+//!
+//!   * [`DebugCuIndex`](./struct.DebugCuIndex.html): The `.debug_cu_index` section.
+//!
+//!   * [`DebugTuIndex`](./struct.DebugTuIndex.html): The `.debug_tu_index` section.
+//!
+//!   * [`EhFrame`](./struct.EhFrame.html): The `.eh_frame` section.
+//!
+//!   * [`EhFrameHdr`](./struct.EhFrameHdr.html): The `.eh_frame_hdr` section.
+//!
+//! * Each section type exposes methods for accessing the debugging data encoded
+//! in that section. For example, the [`DebugInfo`](./struct.DebugInfo.html)
+//! struct has the [`units`](./struct.DebugInfo.html#method.units) method for
+//! iterating over the compilation units defined within it.
+//!
+//! * Offsets into a section are strongly typed: an offset into `.debug_info` is
+//! the [`DebugInfoOffset`](./struct.DebugInfoOffset.html) type. It cannot be
+//! used to index into the [`DebugLine`](./struct.DebugLine.html) type because
+//! `DebugLine` represents the `.debug_line` section. There are similar types
+//! for offsets relative to a compilation unit rather than a section.
+//!
+//! ## Using with `FallibleIterator`
+//!
+//! The standard library's `Iterator` trait and related APIs do not play well
+//! with iterators where the `next` operation is fallible. One can make the
+//! `Iterator`'s associated `Item` type be a `Result<T, E>`, however the
+//! provided methods cannot gracefully handle the case when an `Err` is
+//! returned.
+//!
+//! This situation led to the
+//! [`fallible-iterator`](https://crates.io/crates/fallible-iterator) crate's
+//! existence. You can read more of the rationale for its existence in its
+//! docs. The crate provides the helpers you have come to expect (eg `map`,
+//! `filter`, etc) for iterators that can fail.
+//!
+//! `gimli`'s many lazy parsing iterators are a perfect match for the
+//! `fallible-iterator` crate's `FallibleIterator` trait because parsing is not
+//! done eagerly. Parse errors later in the input might only be discovered after
+//! having iterated through many items.
+//!
+//! To use `gimli` iterators with `FallibleIterator`, import the crate and trait
+//! into your code:
+//!
+//! ```
+//! # #[cfg(feature = "fallible-iterator")]
+//! # fn foo() {
+//! // Use the `FallibleIterator` trait so its methods are in scope!
+//! use fallible_iterator::FallibleIterator;
+//! use gimli::{DebugAranges, EndianSlice, LittleEndian};
+//!
+//! fn find_sum_of_address_range_lengths(aranges: DebugAranges<EndianSlice<LittleEndian>>)
+//!     -> gimli::Result<u64>
+//! {
+//!     // `DebugAranges::headers` returns a `FallibleIterator`!
+//!     aranges.headers()
+//!         // `flat_map` is provided by `FallibleIterator`!
+//!         .flat_map(|header| Ok(header.entries()))
+//!         // `map` is provided by `FallibleIterator`!
+//!         .map(|arange| Ok(arange.length()))
+//!         // `fold` is provided by `FallibleIterator`!
+//!         .fold(0, |sum, len| Ok(sum + len))
+//! }
+//! # }
+//! # fn main() {}
+//! ```
+
+use core::fmt::{self, Debug};
+use core::result;
+#[cfg(feature = "std")]
+use std::{error, io};
+
+use crate::common::{Register, SectionId};
+use crate::constants;
+
+mod util;
+pub use util::*;
+
+mod addr;
+pub use self::addr::*;
+
+mod cfi;
+pub use self::cfi::*;
+
+#[cfg(feature = "read")]
+mod dwarf;
+#[cfg(feature = "read")]
+pub use self::dwarf::*;
+
+mod endian_slice;
+pub use self::endian_slice::*;
+
+#[cfg(feature = "endian-reader")]
+mod endian_reader;
+#[cfg(feature = "endian-reader")]
+pub use self::endian_reader::*;
+
+mod reader;
+pub use self::reader::*;
+
+#[cfg(feature = "read")]
+mod abbrev;
+#[cfg(feature = "read")]
+pub use self::abbrev::*;
+
+mod aranges;
+pub use self::aranges::*;
+
+mod index;
+pub use self::index::*;
+
+#[cfg(feature = "read")]
+mod line;
+#[cfg(feature = "read")]
+pub use self::line::*;
+
+mod lists;
+
+mod loclists;
+pub use self::loclists::*;
+
+#[cfg(feature = "read")]
+mod lookup;
+
+mod op;
+pub use self::op::*;
+
+#[cfg(feature = "read")]
+mod pubnames;
+#[cfg(feature = "read")]
+pub use self::pubnames::*;
+
+#[cfg(feature = "read")]
+mod pubtypes;
+#[cfg(feature = "read")]
+pub use self::pubtypes::*;
+
+mod rnglists;
+pub use self::rnglists::*;
+
+mod str;
+pub use self::str::*;
+
+/// An offset into the current compilation or type unit.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
+pub struct UnitOffset<T = usize>(pub T);
+
+#[cfg(feature = "read")]
+mod unit;
+#[cfg(feature = "read")]
+pub use self::unit::*;
+
+mod value;
+pub use self::value::*;
+
+/// Indicates that storage should be allocated on heap.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct StoreOnHeap;
+
+/// `EndianBuf` has been renamed to `EndianSlice`. For ease of upgrading across
+/// `gimli` versions, we export this type alias.
+#[deprecated(note = "EndianBuf has been renamed to EndianSlice, use that instead.")]
+pub type EndianBuf<'input, Endian> = EndianSlice<'input, Endian>;
+
+/// An error that occurred when parsing.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Error {
+    /// An I/O error occurred while reading.
+    Io,
+    /// Found a PC relative pointer, but the section base is undefined.
+    PcRelativePointerButSectionBaseIsUndefined,
+    /// Found a `.text` relative pointer, but the `.text` base is undefined.
+    TextRelativePointerButTextBaseIsUndefined,
+    /// Found a data relative pointer, but the data base is undefined.
+    DataRelativePointerButDataBaseIsUndefined,
+    /// Found a function relative pointer in a context that does not have a
+    /// function base.
+    FuncRelativePointerInBadContext,
+    /// Cannot parse a pointer with a `DW_EH_PE_omit` encoding.
+    CannotParseOmitPointerEncoding,
+    /// An error parsing an unsigned LEB128 value.
+    BadUnsignedLeb128,
+    /// An error parsing a signed LEB128 value.
+    BadSignedLeb128,
+    /// An abbreviation declared that its tag is zero, but zero is reserved for
+    /// null records.
+    AbbreviationTagZero,
+    /// An attribute specification declared that its form is zero, but zero is
+    /// reserved for null records.
+    AttributeFormZero,
+    /// The abbreviation's has-children byte was not one of
+    /// `DW_CHILDREN_{yes,no}`.
+    BadHasChildren,
+    /// The specified length is impossible.
+    BadLength,
+    /// Found an unknown `DW_FORM_*` type.
+    UnknownForm,
+    /// Expected a zero, found something else.
+    ExpectedZero,
+    /// Found an abbreviation code that has already been used.
+    DuplicateAbbreviationCode,
+    /// Found a duplicate arange.
+    DuplicateArange,
+    /// Found an unknown reserved length value.
+    UnknownReservedLength,
+    /// Found an unknown DWARF version.
+    UnknownVersion(u64),
+    /// Found a record with an unknown abbreviation code.
+    UnknownAbbreviation,
+    /// Hit the end of input before it was expected.
+    UnexpectedEof(ReaderOffsetId),
+    /// Read a null entry before it was expected.
+    UnexpectedNull,
+    /// Found an unknown standard opcode.
+    UnknownStandardOpcode(constants::DwLns),
+    /// Found an unknown extended opcode.
+    UnknownExtendedOpcode(constants::DwLne),
+    /// The specified address size is not supported.
+    UnsupportedAddressSize(u8),
+    /// The specified offset size is not supported.
+    UnsupportedOffsetSize(u8),
+    /// The specified field size is not supported.
+    UnsupportedFieldSize(u8),
+    /// The minimum instruction length must not be zero.
+    MinimumInstructionLengthZero,
+    /// The maximum operations per instruction must not be zero.
+    MaximumOperationsPerInstructionZero,
+    /// The line range must not be zero.
+    LineRangeZero,
+    /// The opcode base must not be zero.
+    OpcodeBaseZero,
+    /// Found an invalid UTF-8 string.
+    BadUtf8,
+    /// Expected to find the CIE ID, but found something else.
+    NotCieId,
+    /// Expected to find a pointer to a CIE, but found the CIE ID instead.
+    NotCiePointer,
+    /// Expected to find a pointer to an FDE, but found a CIE instead.
+    NotFdePointer,
+    /// Invalid branch target for a DW_OP_bra or DW_OP_skip.
+    BadBranchTarget(u64),
+    /// DW_OP_push_object_address used but no address passed in.
+    InvalidPushObjectAddress,
+    /// Not enough items on the stack when evaluating an expression.
+    NotEnoughStackItems,
+    /// Too many iterations to compute the expression.
+    TooManyIterations,
+    /// An unrecognized operation was found while parsing a DWARF
+    /// expression.
+    InvalidExpression(constants::DwOp),
+    /// An unsupported operation was found while evaluating a DWARF expression.
+    UnsupportedEvaluation,
+    /// The expression had a piece followed by an expression
+    /// terminator without a piece.
+    InvalidPiece,
+    /// An expression-terminating operation was followed by something
+    /// other than the end of the expression or a piece operation.
+    InvalidExpressionTerminator(u64),
+    /// Division or modulus by zero when evaluating an expression.
+    DivisionByZero,
+    /// An expression operation used mismatching types.
+    TypeMismatch,
+    /// An expression operation required an integral type but saw a
+    /// floating point type.
+    IntegralTypeRequired,
+    /// An expression operation used types that are not supported.
+    UnsupportedTypeOperation,
+    /// The shift value in an expression must be a non-negative integer.
+    InvalidShiftExpression,
+    /// An unknown DW_CFA_* instruction.
+    UnknownCallFrameInstruction(constants::DwCfa),
+    /// The end of an address range was before the beginning.
+    InvalidAddressRange,
+    /// The end offset of a loc list entry was before the beginning.
+    InvalidLocationAddressRange,
+    /// Encountered a call frame instruction in a context in which it is not
+    /// valid.
+    CfiInstructionInInvalidContext,
+    /// When evaluating call frame instructions, found a `DW_CFA_restore_state`
+    /// stack pop instruction, but the stack was empty, and had nothing to pop.
+    PopWithEmptyStack,
+    /// Do not have unwind info for the given address.
+    NoUnwindInfoForAddress,
+    /// An offset value was larger than the maximum supported value.
+    UnsupportedOffset,
+    /// The given pointer encoding is either unknown or invalid.
+    UnknownPointerEncoding,
+    /// Did not find an entry at the given offset.
+    NoEntryAtGivenOffset,
+    /// The given offset is out of bounds.
+    OffsetOutOfBounds,
+    /// Found an unknown CFI augmentation.
+    UnknownAugmentation,
+    /// We do not support the given pointer encoding yet.
+    UnsupportedPointerEncoding,
+    /// Registers larger than `u16` are not supported.
+    UnsupportedRegister(u64),
+    /// The CFI program defined more register rules than we have storage for.
+    TooManyRegisterRules,
+    /// Attempted to push onto the CFI or evaluation stack, but it was already
+    /// at full capacity.
+    StackFull,
+    /// The `.eh_frame_hdr` binary search table claims to be variable-length encoded,
+    /// which makes binary search impossible.
+    VariableLengthSearchTable,
+    /// The `DW_UT_*` value for this unit is not supported yet.
+    UnsupportedUnitType,
+    /// Ranges using AddressIndex are not supported yet.
+    UnsupportedAddressIndex,
+    /// Nonzero segment selector sizes aren't supported yet.
+    UnsupportedSegmentSize,
+    /// A compilation unit or type unit is missing its top level DIE.
+    MissingUnitDie,
+    /// A DIE attribute used an unsupported form.
+    UnsupportedAttributeForm,
+    /// Missing DW_LNCT_path in file entry format.
+    MissingFileEntryFormatPath,
+    /// Expected an attribute value to be a string form.
+    ExpectedStringAttributeValue,
+    /// `DW_FORM_implicit_const` used in an invalid context.
+    InvalidImplicitConst,
+    /// Invalid section count in `.dwp` index.
+    InvalidIndexSectionCount,
+    /// Invalid slot count in `.dwp` index.
+    InvalidIndexSlotCount,
+    /// Invalid hash row in `.dwp` index.
+    InvalidIndexRow,
+    /// Unknown section type in `.dwp` index.
+    UnknownIndexSection,
+}
+
+impl fmt::Display for Error {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter) -> ::core::result::Result<(), fmt::Error> {
+        write!(f, "{}", self.description())
+    }
+}
+
+impl Error {
+    /// A short description of the error.
+    pub fn description(&self) -> &str {
+        match *self {
+            Error::Io => "An I/O error occurred while reading.",
+            Error::PcRelativePointerButSectionBaseIsUndefined => {
+                "Found a PC relative pointer, but the section base is undefined."
+            }
+            Error::TextRelativePointerButTextBaseIsUndefined => {
+                "Found a `.text` relative pointer, but the `.text` base is undefined."
+            }
+            Error::DataRelativePointerButDataBaseIsUndefined => {
+                "Found a data relative pointer, but the data base is undefined."
+            }
+            Error::FuncRelativePointerInBadContext => {
+                "Found a function relative pointer in a context that does not have a function base."
+            }
+            Error::CannotParseOmitPointerEncoding => {
+                "Cannot parse a pointer with a `DW_EH_PE_omit` encoding."
+            }
+            Error::BadUnsignedLeb128 => "An error parsing an unsigned LEB128 value",
+            Error::BadSignedLeb128 => "An error parsing a signed LEB128 value",
+            Error::AbbreviationTagZero => {
+                "An abbreviation declared that its tag is zero,
+                 but zero is reserved for null records"
+            }
+            Error::AttributeFormZero => {
+                "An attribute specification declared that its form is zero,
+                 but zero is reserved for null records"
+            }
+            Error::BadHasChildren => {
+                "The abbreviation's has-children byte was not one of
+                 `DW_CHILDREN_{yes,no}`"
+            }
+            Error::BadLength => "The specified length is impossible",
+            Error::UnknownForm => "Found an unknown `DW_FORM_*` type",
+            Error::ExpectedZero => "Expected a zero, found something else",
+            Error::DuplicateAbbreviationCode => {
+                "Found an abbreviation code that has already been used"
+            }
+            Error::DuplicateArange => "Found a duplicate arange",
+            Error::UnknownReservedLength => "Found an unknown reserved length value",
+            Error::UnknownVersion(_) => "Found an unknown DWARF version",
+            Error::UnknownAbbreviation => "Found a record with an unknown abbreviation code",
+            Error::UnexpectedEof(_) => "Hit the end of input before it was expected",
+            Error::UnexpectedNull => "Read a null entry before it was expected.",
+            Error::UnknownStandardOpcode(_) => "Found an unknown standard opcode",
+            Error::UnknownExtendedOpcode(_) => "Found an unknown extended opcode",
+            Error::UnsupportedAddressSize(_) => "The specified address size is not supported",
+            Error::UnsupportedOffsetSize(_) => "The specified offset size is not supported",
+            Error::UnsupportedFieldSize(_) => "The specified field size is not supported",
+            Error::MinimumInstructionLengthZero => {
+                "The minimum instruction length must not be zero."
+            }
+            Error::MaximumOperationsPerInstructionZero => {
+                "The maximum operations per instruction must not be zero."
+            }
+            Error::LineRangeZero => "The line range must not be zero.",
+            Error::OpcodeBaseZero => "The opcode base must not be zero.",
+            Error::BadUtf8 => "Found an invalid UTF-8 string.",
+            Error::NotCieId => "Expected to find the CIE ID, but found something else.",
+            Error::NotCiePointer => "Expected to find a CIE pointer, but found the CIE ID instead.",
+            Error::NotFdePointer => {
+                "Expected to find an FDE pointer, but found a CIE pointer instead."
+            }
+            Error::BadBranchTarget(_) => "Invalid branch target in DWARF expression",
+            Error::InvalidPushObjectAddress => {
+                "DW_OP_push_object_address used but no object address given"
+            }
+            Error::NotEnoughStackItems => "Not enough items on stack when evaluating expression",
+            Error::TooManyIterations => "Too many iterations to evaluate DWARF expression",
+            Error::InvalidExpression(_) => "Invalid opcode in DWARF expression",
+            Error::UnsupportedEvaluation => "Unsupported operation when evaluating expression",
+            Error::InvalidPiece => {
+                "DWARF expression has piece followed by non-piece expression at end"
+            }
+            Error::InvalidExpressionTerminator(_) => "Expected DW_OP_piece or DW_OP_bit_piece",
+            Error::DivisionByZero => "Division or modulus by zero when evaluating expression",
+            Error::TypeMismatch => "Type mismatch when evaluating expression",
+            Error::IntegralTypeRequired => "Integral type expected when evaluating expression",
+            Error::UnsupportedTypeOperation => {
+                "An expression operation used types that are not supported"
+            }
+            Error::InvalidShiftExpression => {
+                "The shift value in an expression must be a non-negative integer."
+            }
+            Error::UnknownCallFrameInstruction(_) => "An unknown DW_CFA_* instructiion",
+            Error::InvalidAddressRange => {
+                "The end of an address range must not be before the beginning."
+            }
+            Error::InvalidLocationAddressRange => {
+                "The end offset of a location list entry must not be before the beginning."
+            }
+            Error::CfiInstructionInInvalidContext => {
+                "Encountered a call frame instruction in a context in which it is not valid."
+            }
+            Error::PopWithEmptyStack => {
+                "When evaluating call frame instructions, found a `DW_CFA_restore_state` stack pop \
+                 instruction, but the stack was empty, and had nothing to pop."
+            }
+            Error::NoUnwindInfoForAddress => "Do not have unwind info for the given address.",
+            Error::UnsupportedOffset => {
+                "An offset value was larger than the maximum supported value."
+            }
+            Error::UnknownPointerEncoding => {
+                "The given pointer encoding is either unknown or invalid."
+            }
+            Error::NoEntryAtGivenOffset => "Did not find an entry at the given offset.",
+            Error::OffsetOutOfBounds => "The given offset is out of bounds.",
+            Error::UnknownAugmentation => "Found an unknown CFI augmentation.",
+            Error::UnsupportedPointerEncoding => {
+                "We do not support the given pointer encoding yet."
+            }
+            Error::UnsupportedRegister(_) => "Registers larger than `u16` are not supported.",
+            Error::TooManyRegisterRules => {
+                "The CFI program defined more register rules than we have storage for."
+            }
+            Error::StackFull => {
+                "Attempted to push onto the CFI stack, but it was already at full capacity."
+            }
+            Error::VariableLengthSearchTable => {
+                "The `.eh_frame_hdr` binary search table claims to be variable-length encoded, \
+                 which makes binary search impossible."
+            }
+            Error::UnsupportedUnitType => "The `DW_UT_*` value for this unit is not supported yet",
+            Error::UnsupportedAddressIndex => "Ranges involving AddressIndex are not supported yet",
+            Error::UnsupportedSegmentSize => "Nonzero segment size not supported yet",
+            Error::MissingUnitDie => {
+                "A compilation unit or type unit is missing its top level DIE."
+            }
+            Error::UnsupportedAttributeForm => "A DIE attribute used an unsupported form.",
+            Error::MissingFileEntryFormatPath => "Missing DW_LNCT_path in file entry format.",
+            Error::ExpectedStringAttributeValue => {
+                "Expected an attribute value to be a string form."
+            }
+            Error::InvalidImplicitConst => "DW_FORM_implicit_const used in an invalid context.",
+            Error::InvalidIndexSectionCount => "Invalid section count in `.dwp` index.",
+            Error::InvalidIndexSlotCount => "Invalid slot count in `.dwp` index.",
+            Error::InvalidIndexRow => "Invalid hash row in `.dwp` index.",
+            Error::UnknownIndexSection => "Unknown section type in `.dwp` index.",
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl error::Error for Error {}
+
+#[cfg(feature = "std")]
+impl From<io::Error> for Error {
+    fn from(_: io::Error) -> Self {
+        Error::Io
+    }
+}
+
+/// The result of a parse.
+pub type Result<T> = result::Result<T, Error>;
+
+/// A convenience trait for loading DWARF sections from object files.  To be
+/// used like:
+///
+/// ```
+/// use gimli::{DebugInfo, EndianSlice, LittleEndian, Reader, Section};
+///
+/// let buf = [0x00, 0x01, 0x02, 0x03];
+/// let reader = EndianSlice::new(&buf, LittleEndian);
+/// let loader = |name| -> Result<_, ()> { Ok(reader) };
+///
+/// let debug_info: DebugInfo<_> = Section::load(loader).unwrap();
+/// ```
+pub trait Section<R>: From<R> {
+    /// Returns the section id for this type.
+    fn id() -> SectionId;
+
+    /// Returns the ELF section name for this type.
+    fn section_name() -> &'static str {
+        Self::id().name()
+    }
+
+    /// Returns the ELF section name (if any) for this type when used in a dwo
+    /// file.
+    fn dwo_section_name() -> Option<&'static str> {
+        Self::id().dwo_name()
+    }
+
+    /// Returns the XCOFF section name (if any) for this type when used in a XCOFF
+    /// file.
+    fn xcoff_section_name() -> Option<&'static str> {
+        Self::id().xcoff_name()
+    }
+
+    /// Try to load the section using the given loader function.
+    fn load<F, E>(f: F) -> core::result::Result<Self, E>
+    where
+        F: FnOnce(SectionId) -> core::result::Result<R, E>,
+    {
+        f(Self::id()).map(From::from)
+    }
+
+    /// Returns the `Reader` for this section.
+    fn reader(&self) -> &R
+    where
+        R: Reader;
+
+    /// Returns the subrange of the section that is the contribution of
+    /// a unit in a `.dwp` file.
+    fn dwp_range(&self, offset: u32, size: u32) -> Result<Self>
+    where
+        R: Reader,
+    {
+        let mut data = self.reader().clone();
+        data.skip(R::Offset::from_u32(offset))?;
+        data.truncate(R::Offset::from_u32(size))?;
+        Ok(data.into())
+    }
+
+    /// Returns the `Reader` for this section.
+    fn lookup_offset_id(&self, id: ReaderOffsetId) -> Option<(SectionId, R::Offset)>
+    where
+        R: Reader,
+    {
+        self.reader()
+            .lookup_offset_id(id)
+            .map(|offset| (Self::id(), offset))
+    }
+}
+
+impl Register {
+    pub(crate) fn from_u64(x: u64) -> Result<Register> {
+        let y = x as u16;
+        if u64::from(y) == x {
+            Ok(Register(y))
+        } else {
+            Err(Error::UnsupportedRegister(x))
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::common::Format;
+    use crate::endianity::LittleEndian;
+    use test_assembler::{Endian, Section};
+
+    #[test]
+    fn test_parse_initial_length_32_ok() {
+        let section = Section::with_endian(Endian::Little).L32(0x7856_3412);
+        let buf = section.get_contents().unwrap();
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_initial_length() {
+            Ok((length, format)) => {
+                assert_eq!(input.len(), 0);
+                assert_eq!(format, Format::Dwarf32);
+                assert_eq!(0x7856_3412, length);
+            }
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        }
+    }
+
+    #[test]
+    fn test_parse_initial_length_64_ok() {
+        let section = Section::with_endian(Endian::Little)
+            // Dwarf_64_INITIAL_UNIT_LENGTH
+            .L32(0xffff_ffff)
+            // Actual length
+            .L64(0xffde_bc9a_7856_3412);
+        let buf = section.get_contents().unwrap();
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+
+        #[cfg(target_pointer_width = "64")]
+        match input.read_initial_length() {
+            Ok((length, format)) => {
+                assert_eq!(input.len(), 0);
+                assert_eq!(format, Format::Dwarf64);
+                assert_eq!(0xffde_bc9a_7856_3412, length);
+            }
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        }
+
+        #[cfg(target_pointer_width = "32")]
+        match input.read_initial_length() {
+            Err(Error::UnsupportedOffset) => {}
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+
+    #[test]
+    fn test_parse_initial_length_unknown_reserved_value() {
+        let section = Section::with_endian(Endian::Little).L32(0xffff_fffe);
+        let buf = section.get_contents().unwrap();
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_initial_length() {
+            Err(Error::UnknownReservedLength) => assert!(true),
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+
+    #[test]
+    fn test_parse_initial_length_incomplete() {
+        let buf = [0xff, 0xff, 0xff]; // Need at least 4 bytes.
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_initial_length() {
+            Err(Error::UnexpectedEof(_)) => assert!(true),
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+
+    #[test]
+    fn test_parse_initial_length_64_incomplete() {
+        let section = Section::with_endian(Endian::Little)
+            // Dwarf_64_INITIAL_UNIT_LENGTH
+            .L32(0xffff_ffff)
+            // Actual length is not long enough.
+            .L32(0x7856_3412);
+        let buf = section.get_contents().unwrap();
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_initial_length() {
+            Err(Error::UnexpectedEof(_)) => assert!(true),
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+
+    #[test]
+    fn test_parse_offset_32() {
+        let section = Section::with_endian(Endian::Little).L32(0x0123_4567);
+        let buf = section.get_contents().unwrap();
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_offset(Format::Dwarf32) {
+            Ok(val) => {
+                assert_eq!(input.len(), 0);
+                assert_eq!(val, 0x0123_4567);
+            }
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+
+    #[test]
+    fn test_parse_offset_64_small() {
+        let section = Section::with_endian(Endian::Little).L64(0x0123_4567);
+        let buf = section.get_contents().unwrap();
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_offset(Format::Dwarf64) {
+            Ok(val) => {
+                assert_eq!(input.len(), 0);
+                assert_eq!(val, 0x0123_4567);
+            }
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+
+    #[test]
+    #[cfg(target_pointer_width = "64")]
+    fn test_parse_offset_64_large() {
+        let section = Section::with_endian(Endian::Little).L64(0x0123_4567_89ab_cdef);
+        let buf = section.get_contents().unwrap();
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_offset(Format::Dwarf64) {
+            Ok(val) => {
+                assert_eq!(input.len(), 0);
+                assert_eq!(val, 0x0123_4567_89ab_cdef);
+            }
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+
+    #[test]
+    #[cfg(target_pointer_width = "32")]
+    fn test_parse_offset_64_large() {
+        let section = Section::with_endian(Endian::Little).L64(0x0123_4567_89ab_cdef);
+        let buf = section.get_contents().unwrap();
+
+        let input = &mut EndianSlice::new(&buf, LittleEndian);
+        match input.read_offset(Format::Dwarf64) {
+            Err(Error::UnsupportedOffset) => assert!(true),
+            otherwise => panic!("Unexpected result: {:?}", otherwise),
+        };
+    }
+}