vendor/gimli-0.26.2/src/write/mod.rs - toolchain/rustc - Git at Google

 //! Write DWARF debugging information.
 //!
 //! ## API Structure
 //!
 //! This module works by building up a representation of the debugging information
 //! in memory, and then writing it all at once. It supports two major use cases:
 //!
 //! * Use the [`DwarfUnit`](./struct.DwarfUnit.html) type when writing DWARF
 //! for a single compilation unit.
 //!
 //! * Use the [`Dwarf`](./struct.Dwarf.html) type when writing DWARF for multiple
 //! compilation units.
 //!
 //! The module also supports reading in DWARF debugging information and writing it out
 //! again, possibly after modifying it. Create a [`read::Dwarf`](../read/struct.Dwarf.html)
 //! instance, and then use [`Dwarf::from`](./struct.Dwarf.html#method.from) to convert
 //! it to a writable instance.
 //!
 //! ## Example Usage
 //!
 //! Write a compilation unit containing only the top level DIE.
 //!
 //! ```rust
 //! use gimli::write::{
 //!     Address, AttributeValue, DwarfUnit, EndianVec, Error, Range, RangeList, Sections,
 //! };
 //!
 //! fn example() -> Result<(), Error> {
 //!     // Choose the encoding parameters.
 //!     let encoding = gimli::Encoding {
 //!         format: gimli::Format::Dwarf32,
 //!         version: 5,
 //!         address_size: 8,
 //!     };
 //!     // Create a container for a single compilation unit.
 //!     let mut dwarf = DwarfUnit::new(encoding);
 //!     // Set a range attribute on the root DIE.
 //!     let range_list = RangeList(vec![Range::StartLength {
 //!         begin: Address::Constant(0x100),
 //!         length: 42,
 //!     }]);
 //!     let range_list_id = dwarf.unit.ranges.add(range_list);
 //!     let root = dwarf.unit.root();
 //!     dwarf.unit.get_mut(root).set(
 //!         gimli::DW_AT_ranges,
 //!         AttributeValue::RangeListRef(range_list_id),
 //!     );
 //!     // Create a `Vec` for each DWARF section.
 //!     let mut sections = Sections::new(EndianVec::new(gimli::LittleEndian));
 //!     // Finally, write the DWARF data to the sections.
 //!     dwarf.write(&mut sections)?;
 //!     sections.for_each(|id, data| {
 //!         // Here you can add the data to the output object file.
 //!         Ok(())
 //!     })
 //! }
 //! # fn main() {
 //! #     example().unwrap();
 //! # }

 use std::error;
 use std::fmt;
 use std::result;

 use crate::constants;

 mod endian_vec;
 pub use self::endian_vec::*;

 mod writer;
 pub use self::writer::*;

 #[macro_use]
 mod section;
 pub use self::section::*;

 macro_rules! define_id {
     ($name:ident, $docs:expr) => {
         #[doc=$docs]
         #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
         pub struct $name {
             base_id: BaseId,
             index: usize,
         }

         impl $name {
             #[inline]
             fn new(base_id: BaseId, index: usize) -> Self {
                 $name { base_id, index }
             }
         }
     };
 }

 macro_rules! define_offsets {
     ($offsets:ident: $id:ident => $offset:ident, $off_doc:expr) => {
         #[doc=$off_doc]
         #[derive(Debug)]
         pub struct $offsets {
             base_id: BaseId,
             // We know ids start at 0.
             offsets: Vec<$offset>,
         }

         impl $offsets {
             /// Return an empty list of offsets.
             #[inline]
             pub fn none() -> Self {
                 $offsets {
                     base_id: BaseId::default(),
                     offsets: Vec::new(),
                 }
             }

             /// Get the offset
             ///
             /// # Panics
             ///
             /// Panics if `id` is invalid.
             #[inline]
             pub fn get(&self, id: $id) -> $offset {
                 debug_assert_eq!(self.base_id, id.base_id);
                 self.offsets[id.index]
             }

             /// Return the number of offsets.
             #[inline]
             pub fn count(&self) -> usize {
                 self.offsets.len()
             }
         }
     };
 }

 mod abbrev;
 pub use self::abbrev::*;

 mod cfi;
 pub use self::cfi::*;

 mod dwarf;
 pub use self::dwarf::*;

 mod line;
 pub use self::line::*;

 mod loc;
 pub use self::loc::*;

 mod op;
 pub use self::op::*;

 mod range;
 pub use self::range::*;

 mod str;
 pub use self::str::*;

 mod unit;
 pub use self::unit::*;

 /// An error that occurred when writing.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum Error {
     /// The given offset is out of bounds.
     OffsetOutOfBounds,
     /// The given length is out of bounds.
     LengthOutOfBounds,
     /// The attribute value is an invalid for writing.
     InvalidAttributeValue,
     /// The value is too large for the encoding form.
     ValueTooLarge,
     /// Unsupported word size.
     UnsupportedWordSize(u8),
     /// Unsupported DWARF version.
     UnsupportedVersion(u16),
     /// The unit length is too large for the requested DWARF format.
     InitialLengthOverflow,
     /// The address is invalid.
     InvalidAddress,
     /// The reference is invalid.
     InvalidReference,
     /// A requested feature requires a different DWARF version.
     NeedVersion(u16),
     /// Strings in line number program have mismatched forms.
     LineStringFormMismatch,
     /// The range is empty or otherwise invalid.
     InvalidRange,
     /// The line number program encoding is incompatible with the unit encoding.
     IncompatibleLineProgramEncoding,
     /// Could not encode code offset for a frame instruction.
     InvalidFrameCodeOffset(u32),
     /// Could not encode data offset for a frame instruction.
     InvalidFrameDataOffset(i32),
     /// Unsupported eh_frame pointer encoding.
     UnsupportedPointerEncoding(constants::DwEhPe),
     /// Unsupported reference in CFI expression.
     UnsupportedCfiExpressionReference,
     /// Unsupported forward reference in expression.
     UnsupportedExpressionForwardReference,
 }

 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
         match *self {
             Error::OffsetOutOfBounds => write!(f, "The given offset is out of bounds."),
             Error::LengthOutOfBounds => write!(f, "The given length is out of bounds."),
             Error::InvalidAttributeValue => {
                 write!(f, "The attribute value is an invalid for writing.")
             }
             Error::ValueTooLarge => write!(f, "The value is too large for the encoding form."),
             Error::UnsupportedWordSize(size) => write!(f, "Unsupported word size: {}", size),
             Error::UnsupportedVersion(version) => {
                 write!(f, "Unsupported DWARF version: {}", version)
             }
             Error::InitialLengthOverflow => write!(
                 f,
                 "The unit length is too large for the requested DWARF format."
             ),
             Error::InvalidAddress => write!(f, "The address is invalid."),
             Error::InvalidReference => write!(f, "The reference is invalid."),
             Error::NeedVersion(version) => write!(
                 f,
                 "A requested feature requires a DWARF version {}.",
                 version
             ),
             Error::LineStringFormMismatch => {
                 write!(f, "Strings in line number program have mismatched forms.")
             }
             Error::InvalidRange => write!(f, "The range is empty or otherwise invalid."),
             Error::IncompatibleLineProgramEncoding => write!(
                 f,
                 "The line number program encoding is incompatible with the unit encoding."
             ),
             Error::InvalidFrameCodeOffset(offset) => write!(
                 f,
                 "Could not encode code offset ({}) for a frame instruction.",
                 offset,
             ),
             Error::InvalidFrameDataOffset(offset) => write!(
                 f,
                 "Could not encode data offset ({}) for a frame instruction.",
                 offset,
             ),
             Error::UnsupportedPointerEncoding(eh_pe) => {
                 write!(f, "Unsupported eh_frame pointer encoding ({}).", eh_pe)
             }
             Error::UnsupportedCfiExpressionReference => {
                 write!(f, "Unsupported reference in CFI expression.")
             }
             Error::UnsupportedExpressionForwardReference => {
                 write!(f, "Unsupported forward reference in expression.")
             }
         }
     }
 }

 impl error::Error for Error {}

 /// The result of a write.
 pub type Result<T> = result::Result<T, Error>;

 /// An address.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum Address {
     /// A fixed address that does not require relocation.
     Constant(u64),
     /// An address that is relative to a symbol which may be relocated.
     Symbol {
         /// The symbol that the address is relative to.
         ///
         /// The meaning of this value is decided by the writer, but
         /// will typically be an index into a symbol table.
         symbol: usize,
         /// The offset of the address relative to the symbol.
         ///
         /// This will typically be used as the addend in a relocation.
         addend: i64,
     },
 }

 /// A reference to a `.debug_info` entry.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum Reference {
     /// An external symbol.
     ///
     /// The meaning of this value is decided by the writer, but
     /// will typically be an index into a symbol table.
     Symbol(usize),
     /// An entry in the same section.
     ///
     /// This only supports references in units that are emitted together.
     Entry(UnitId, UnitEntryId),
 }

 // This type is only used in debug assertions.
 #[cfg(not(debug_assertions))]
 type BaseId = ();

 #[cfg(debug_assertions)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 struct BaseId(usize);

 #[cfg(debug_assertions)]
 impl Default for BaseId {
     fn default() -> Self {
         use std::sync::atomic;
         static BASE_ID: atomic::AtomicUsize = atomic::AtomicUsize::new(0);
         BaseId(BASE_ID.fetch_add(1, atomic::Ordering::Relaxed))
     }
 }

 #[cfg(feature = "read")]
 mod convert {
     use super::*;
     use crate::read;

     pub(crate) use super::unit::convert::*;

     /// An error that occurred when converting a read value into a write value.
     #[derive(Debug, Clone, Copy, PartialEq, Eq)]
     pub enum ConvertError {
         /// An error occurred when reading.
         Read(read::Error),
         /// Writing of this attribute value is not implemented yet.
         UnsupportedAttributeValue,
         /// This attribute value is an invalid name/form combination.
         InvalidAttributeValue,
         /// A `.debug_info` reference does not refer to a valid entry.
         InvalidDebugInfoOffset,
         /// An address could not be converted.
         InvalidAddress,
         /// Writing this line number instruction is not implemented yet.
         UnsupportedLineInstruction,
         /// Writing this form of line string is not implemented yet.
         UnsupportedLineStringForm,
         /// A `.debug_line` file index is invalid.
         InvalidFileIndex,
         /// A `.debug_line` directory index is invalid.
         InvalidDirectoryIndex,
         /// A `.debug_line` line base is invalid.
         InvalidLineBase,
         /// A `.debug_line` reference is invalid.
         InvalidLineRef,
         /// A `.debug_info` unit entry reference is invalid.
         InvalidUnitRef,
         /// A `.debug_info` reference is invalid.
         InvalidDebugInfoRef,
         /// Invalid relative address in a range list.
         InvalidRangeRelativeAddress,
         /// Writing this CFI instruction is not implemented yet.
         UnsupportedCfiInstruction,
         /// Writing indirect pointers is not implemented yet.
         UnsupportedIndirectAddress,
         /// Writing this expression operation is not implemented yet.
         UnsupportedOperation,
         /// Operation branch target is invalid.
         InvalidBranchTarget,
         /// Writing this unit type is not supported yet.
         UnsupportedUnitType,
     }

     impl fmt::Display for ConvertError {
         fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
             use self::ConvertError::*;
             match *self {
                 Read(ref e) => e.fmt(f),
                 UnsupportedAttributeValue => {
                     write!(f, "Writing of this attribute value is not implemented yet.")
                 }
                 InvalidAttributeValue => write!(
                     f,
                     "This attribute value is an invalid name/form combination."
                 ),
                 InvalidDebugInfoOffset => write!(
                     f,
                     "A `.debug_info` reference does not refer to a valid entry."
                 ),
                 InvalidAddress => write!(f, "An address could not be converted."),
                 UnsupportedLineInstruction => write!(
                     f,
                     "Writing this line number instruction is not implemented yet."
                 ),
                 UnsupportedLineStringForm => write!(
                     f,
                     "Writing this form of line string is not implemented yet."
                 ),
                 InvalidFileIndex => write!(f, "A `.debug_line` file index is invalid."),
                 InvalidDirectoryIndex => write!(f, "A `.debug_line` directory index is invalid."),
                 InvalidLineBase => write!(f, "A `.debug_line` line base is invalid."),
                 InvalidLineRef => write!(f, "A `.debug_line` reference is invalid."),
                 InvalidUnitRef => write!(f, "A `.debug_info` unit entry reference is invalid."),
                 InvalidDebugInfoRef => write!(f, "A `.debug_info` reference is invalid."),
                 InvalidRangeRelativeAddress => {
                     write!(f, "Invalid relative address in a range list.")
                 }
                 UnsupportedCfiInstruction => {
                     write!(f, "Writing this CFI instruction is not implemented yet.")
                 }
                 UnsupportedIndirectAddress => {
                     write!(f, "Writing indirect pointers is not implemented yet.")
                 }
                 UnsupportedOperation => write!(
                     f,
                     "Writing this expression operation is not implemented yet."
                 ),
                 InvalidBranchTarget => write!(f, "Operation branch target is invalid."),
                 UnsupportedUnitType => write!(f, "Writing this unit type is not supported yet."),
             }
         }
     }

     impl error::Error for ConvertError {}

     impl From<read::Error> for ConvertError {
         fn from(e: read::Error) -> Self {
             ConvertError::Read(e)
         }
     }

     /// The result of a conversion.
     pub type ConvertResult<T> = result::Result<T, ConvertError>;
 }
 #[cfg(feature = "read")]
 pub use self::convert::*;
	//! Write DWARF debugging information.
	//!
	//! ## API Structure
	//!
	//! This module works by building up a representation of the debugging information
	//! in memory, and then writing it all at once. It supports two major use cases:
	//!
	//! * Use the [`DwarfUnit`](./struct.DwarfUnit.html) type when writing DWARF
	//! for a single compilation unit.
	//!
	//! * Use the [`Dwarf`](./struct.Dwarf.html) type when writing DWARF for multiple
	//! compilation units.
	//!
	//! The module also supports reading in DWARF debugging information and writing it out
	//! again, possibly after modifying it. Create a [`read::Dwarf`](../read/struct.Dwarf.html)
	//! instance, and then use [`Dwarf::from`](./struct.Dwarf.html#method.from) to convert
	//! it to a writable instance.
	//!
	//! ## Example Usage
	//!
	//! Write a compilation unit containing only the top level DIE.
	//!
	//! ```rust
	//! use gimli::write::{
	//! Address, AttributeValue, DwarfUnit, EndianVec, Error, Range, RangeList, Sections,
	//! };
	//!
	//! fn example() -> Result<(), Error> {
	//! // Choose the encoding parameters.
	//! let encoding = gimli::Encoding {
	//! format: gimli::Format::Dwarf32,
	//! version: 5,
	//! address_size: 8,
	//! };
	//! // Create a container for a single compilation unit.
	//! let mut dwarf = DwarfUnit::new(encoding);
	//! // Set a range attribute on the root DIE.
	//! let range_list = RangeList(vec![Range::StartLength {
	//! begin: Address::Constant(0x100),
	//! length: 42,
	//! }]);
	//! let range_list_id = dwarf.unit.ranges.add(range_list);
	//! let root = dwarf.unit.root();
	//! dwarf.unit.get_mut(root).set(
	//! gimli::DW_AT_ranges,
	//! AttributeValue::RangeListRef(range_list_id),
	//! );
	//! // Create a `Vec` for each DWARF section.
	//! let mut sections = Sections::new(EndianVec::new(gimli::LittleEndian));
	//! // Finally, write the DWARF data to the sections.
	//! dwarf.write(&mut sections)?;
	//! sections.for_each(\|id, data\| {
	//! // Here you can add the data to the output object file.
	//! Ok(())
	//! })
	//! }
	//! # fn main() {
	//! # example().unwrap();
	//! # }

	use std::error;
	use std::fmt;
	use std::result;

	use crate::constants;

	mod endian_vec;
	pub use self::endian_vec::*;

	mod writer;
	pub use self::writer::*;

	#[macro_use]
	mod section;
	pub use self::section::*;

	macro_rules! define_id {
	($name:ident, $docs:expr) => {
	#[doc=$docs]
	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
	pub struct $name {
	base_id: BaseId,
	index: usize,
	}

	impl $name {
	#[inline]
	fn new(base_id: BaseId, index: usize) -> Self {
	$name { base_id, index }
	}
	}
	};
	}

	macro_rules! define_offsets {
	($offsets:ident: $id:ident => $offset:ident, $off_doc:expr) => {
	#[doc=$off_doc]
	#[derive(Debug)]
	pub struct $offsets {
	base_id: BaseId,
	// We know ids start at 0.
	offsets: Vec<$offset>,
	}

	impl $offsets {
	/// Return an empty list of offsets.
	#[inline]
	pub fn none() -> Self {
	$offsets {
	base_id: BaseId::default(),
	offsets: Vec::new(),
	}
	}

	/// Get the offset
	///
	/// # Panics
	///
	/// Panics if `id` is invalid.
	#[inline]
	pub fn get(&self, id: $id) -> $offset {
	debug_assert_eq!(self.base_id, id.base_id);
	self.offsets[id.index]
	}

	/// Return the number of offsets.
	#[inline]
	pub fn count(&self) -> usize {
	self.offsets.len()
	}
	}
	};
	}

	mod abbrev;
	pub use self::abbrev::*;

	mod cfi;
	pub use self::cfi::*;

	mod dwarf;
	pub use self::dwarf::*;

	mod line;
	pub use self::line::*;

	mod loc;
	pub use self::loc::*;

	mod op;
	pub use self::op::*;

	mod range;
	pub use self::range::*;

	mod str;
	pub use self::str::*;

	mod unit;
	pub use self::unit::*;

	/// An error that occurred when writing.
	#[derive(Debug, Clone, Copy, PartialEq, Eq)]
	pub enum Error {
	/// The given offset is out of bounds.
	OffsetOutOfBounds,
	/// The given length is out of bounds.
	LengthOutOfBounds,
	/// The attribute value is an invalid for writing.
	InvalidAttributeValue,
	/// The value is too large for the encoding form.
	ValueTooLarge,
	/// Unsupported word size.
	UnsupportedWordSize(u8),
	/// Unsupported DWARF version.
	UnsupportedVersion(u16),
	/// The unit length is too large for the requested DWARF format.
	InitialLengthOverflow,
	/// The address is invalid.
	InvalidAddress,
	/// The reference is invalid.
	InvalidReference,
	/// A requested feature requires a different DWARF version.
	NeedVersion(u16),
	/// Strings in line number program have mismatched forms.
	LineStringFormMismatch,
	/// The range is empty or otherwise invalid.
	InvalidRange,
	/// The line number program encoding is incompatible with the unit encoding.
	IncompatibleLineProgramEncoding,
	/// Could not encode code offset for a frame instruction.
	InvalidFrameCodeOffset(u32),
	/// Could not encode data offset for a frame instruction.
	InvalidFrameDataOffset(i32),
	/// Unsupported eh_frame pointer encoding.
	UnsupportedPointerEncoding(constants::DwEhPe),
	/// Unsupported reference in CFI expression.
	UnsupportedCfiExpressionReference,
	/// Unsupported forward reference in expression.
	UnsupportedExpressionForwardReference,
	}

	impl fmt::Display for Error {
	fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
	match *self {
	Error::OffsetOutOfBounds => write!(f, "The given offset is out of bounds."),
	Error::LengthOutOfBounds => write!(f, "The given length is out of bounds."),
	Error::InvalidAttributeValue => {
	write!(f, "The attribute value is an invalid for writing.")
	}
	Error::ValueTooLarge => write!(f, "The value is too large for the encoding form."),
	Error::UnsupportedWordSize(size) => write!(f, "Unsupported word size: {}", size),
	Error::UnsupportedVersion(version) => {
	write!(f, "Unsupported DWARF version: {}", version)
	}
	Error::InitialLengthOverflow => write!(
	f,
	"The unit length is too large for the requested DWARF format."
	),
	Error::InvalidAddress => write!(f, "The address is invalid."),
	Error::InvalidReference => write!(f, "The reference is invalid."),
	Error::NeedVersion(version) => write!(
	f,
	"A requested feature requires a DWARF version {}.",
	version
	),
	Error::LineStringFormMismatch => {
	write!(f, "Strings in line number program have mismatched forms.")
	}
	Error::InvalidRange => write!(f, "The range is empty or otherwise invalid."),
	Error::IncompatibleLineProgramEncoding => write!(
	f,
	"The line number program encoding is incompatible with the unit encoding."
	),
	Error::InvalidFrameCodeOffset(offset) => write!(
	f,
	"Could not encode code offset ({}) for a frame instruction.",
	offset,
	),
	Error::InvalidFrameDataOffset(offset) => write!(
	f,
	"Could not encode data offset ({}) for a frame instruction.",
	offset,
	),
	Error::UnsupportedPointerEncoding(eh_pe) => {
	write!(f, "Unsupported eh_frame pointer encoding ({}).", eh_pe)
	}
	Error::UnsupportedCfiExpressionReference => {
	write!(f, "Unsupported reference in CFI expression.")
	}
	Error::UnsupportedExpressionForwardReference => {
	write!(f, "Unsupported forward reference in expression.")
	}
	}
	}
	}

	impl error::Error for Error {}

	/// The result of a write.
	pub type Result<T> = result::Result<T, Error>;

	/// An address.
	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
	pub enum Address {
	/// A fixed address that does not require relocation.
	Constant(u64),
	/// An address that is relative to a symbol which may be relocated.
	Symbol {
	/// The symbol that the address is relative to.
	///
	/// The meaning of this value is decided by the writer, but
	/// will typically be an index into a symbol table.
	symbol: usize,
	/// The offset of the address relative to the symbol.
	///
	/// This will typically be used as the addend in a relocation.
	addend: i64,
	},
	}

	/// A reference to a `.debug_info` entry.
	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
	pub enum Reference {
	/// An external symbol.
	///
	/// The meaning of this value is decided by the writer, but
	/// will typically be an index into a symbol table.
	Symbol(usize),
	/// An entry in the same section.
	///
	/// This only supports references in units that are emitted together.
	Entry(UnitId, UnitEntryId),
	}

	// This type is only used in debug assertions.
	#[cfg(not(debug_assertions))]
	type BaseId = ();

	#[cfg(debug_assertions)]
	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
	struct BaseId(usize);

	#[cfg(debug_assertions)]
	impl Default for BaseId {
	fn default() -> Self {
	use std::sync::atomic;
	static BASE_ID: atomic::AtomicUsize = atomic::AtomicUsize::new(0);
	BaseId(BASE_ID.fetch_add(1, atomic::Ordering::Relaxed))
	}
	}

	#[cfg(feature = "read")]
	mod convert {
	use super::*;
	use crate::read;

	pub(crate) use super::unit::convert::*;

	/// An error that occurred when converting a read value into a write value.
	#[derive(Debug, Clone, Copy, PartialEq, Eq)]
	pub enum ConvertError {
	/// An error occurred when reading.
	Read(read::Error),
	/// Writing of this attribute value is not implemented yet.
	UnsupportedAttributeValue,
	/// This attribute value is an invalid name/form combination.
	InvalidAttributeValue,
	/// A `.debug_info` reference does not refer to a valid entry.
	InvalidDebugInfoOffset,
	/// An address could not be converted.
	InvalidAddress,
	/// Writing this line number instruction is not implemented yet.
	UnsupportedLineInstruction,
	/// Writing this form of line string is not implemented yet.
	UnsupportedLineStringForm,
	/// A `.debug_line` file index is invalid.
	InvalidFileIndex,
	/// A `.debug_line` directory index is invalid.
	InvalidDirectoryIndex,
	/// A `.debug_line` line base is invalid.
	InvalidLineBase,
	/// A `.debug_line` reference is invalid.
	InvalidLineRef,
	/// A `.debug_info` unit entry reference is invalid.
	InvalidUnitRef,
	/// A `.debug_info` reference is invalid.
	InvalidDebugInfoRef,
	/// Invalid relative address in a range list.
	InvalidRangeRelativeAddress,
	/// Writing this CFI instruction is not implemented yet.
	UnsupportedCfiInstruction,
	/// Writing indirect pointers is not implemented yet.
	UnsupportedIndirectAddress,
	/// Writing this expression operation is not implemented yet.
	UnsupportedOperation,
	/// Operation branch target is invalid.
	InvalidBranchTarget,
	/// Writing this unit type is not supported yet.
	UnsupportedUnitType,
	}

	impl fmt::Display for ConvertError {
	fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
	use self::ConvertError::*;
	match *self {
	Read(ref e) => e.fmt(f),
	UnsupportedAttributeValue => {
	write!(f, "Writing of this attribute value is not implemented yet.")
	}
	InvalidAttributeValue => write!(
	f,
	"This attribute value is an invalid name/form combination."
	),
	InvalidDebugInfoOffset => write!(
	f,
	"A `.debug_info` reference does not refer to a valid entry."
	),
	InvalidAddress => write!(f, "An address could not be converted."),
	UnsupportedLineInstruction => write!(
	f,
	"Writing this line number instruction is not implemented yet."
	),
	UnsupportedLineStringForm => write!(
	f,
	"Writing this form of line string is not implemented yet."
	),
	InvalidFileIndex => write!(f, "A `.debug_line` file index is invalid."),
	InvalidDirectoryIndex => write!(f, "A `.debug_line` directory index is invalid."),
	InvalidLineBase => write!(f, "A `.debug_line` line base is invalid."),
	InvalidLineRef => write!(f, "A `.debug_line` reference is invalid."),
	InvalidUnitRef => write!(f, "A `.debug_info` unit entry reference is invalid."),
	InvalidDebugInfoRef => write!(f, "A `.debug_info` reference is invalid."),
	InvalidRangeRelativeAddress => {
	write!(f, "Invalid relative address in a range list.")
	}
	UnsupportedCfiInstruction => {
	write!(f, "Writing this CFI instruction is not implemented yet.")
	}
	UnsupportedIndirectAddress => {
	write!(f, "Writing indirect pointers is not implemented yet.")
	}
	UnsupportedOperation => write!(
	f,
	"Writing this expression operation is not implemented yet."
	),
	InvalidBranchTarget => write!(f, "Operation branch target is invalid."),
	UnsupportedUnitType => write!(f, "Writing this unit type is not supported yet."),
	}
	}
	}

	impl error::Error for ConvertError {}

	impl From<read::Error> for ConvertError {
	fn from(e: read::Error) -> Self {
	ConvertError::Read(e)
	}
	}

	/// The result of a conversion.
	pub type ConvertResult<T> = result::Result<T, ConvertError>;
	}
	#[cfg(feature = "read")]
	pub use self::convert::*;