Crate lsda 

lsda is a library for reading and writing the language-specific data area (LSDA) of GCC-compatible exception handling, as stored in the .gcc_except_table section.

An LSDA describes, for one function, which call sites may throw, where their landing pads are, and which exception types each landing pad handles. The personality routine (such as __gxx_personality_v0) finds it through the L augmentation of the function’s FDE in .eh_frame, or, on Arm, at the end of the function’s .ARM.extab entry.

The format has no standalone specification. It is defined by its producers and consumers, which this crate follows:

• GCC gcc/except.cc (output_one_function_exception_table), the original producer;
• libstdc++ libsupc++/eh_personality.cc and libgcc unwind-pe.h, the reference consumer, including its Arm EHABI and SJLJ variants;
• LLVM CodeGen/AsmPrinter/EHStreamer.cpp and libc++abi cxa_personality.cpp.

Pointer encodings are the DW_EH_PE_* values of the Linux Standard Base Core Specification 5.0, “Exception Frames”.

The API is organised as follows:

• The read module parses an LSDA at a given offset through the Reader trait, with zero-copy EndianSlice as the usual implementation. Iterators return Result<Option<T>>.

• The write module builds an in-memory GccExceptTable and writes it to a Writer such as EndianVec, optionally recording relocations.

• Encoding and Format are shared by both.

The read and write module documentation each start with a complete example.

Cargo features

• read (default): the read module.
• write (default): the write module.
• fallible-iterator: implement fallible_iterator::FallibleIterator for the iterators.

The crate is no_std and requires alloc. The error types implement core::error::Error.

Modules

constants

Constant definitions.

leb128

LEB128 encoding, as used throughout the LSDA.

readread

Read LSDAs from .gcc_except_table (or .ARM.extab).

writewrite

Write LSDAs to .gcc_except_table.

Structs

BaseAddresses

The base addresses that relative pointer encodings are resolved against.

BigEndian

Big endian byte order.

Encoding

A DW_EH_PE_* pointer encoding.

Format

The target properties needed to parse or write an LSDA.

LittleEndian

Little endian byte order.

LsdaOffset

An offset into the section that holds the LSDAs.

Enums

Base

One of the base addresses in BaseAddresses.

RunTimeEndian

Byte order that is selectable at runtime.

Unwinder

The unwinder that the tables are used with.

Traits

Endianity

A trait describing the endianity of some buffer.

Type Aliases

NativeEndianLittle-endian

The native endianity for the target platform.