Dwarf Assembly

A compiler from DWARF unwinding data to native x86_64 binaries.

This repository also contains various experiments, tools, benchmarking scripts, stats scripts, etc. to work on this compiler.

Dependencies

As of now, this project relies on the following libraries:

• libelf
• libdwarf
• libdwarfpp, itself depending on
  • libcxxfileno
  • libsrk31cxx

These libraries are expected to be installed somewhere your compiler can find them. If you are using Archlinux, you can check these PKGBUILDs.

Scripts and directories

• ./generate_eh_elf.py: generate .eh_elf.so files for a binary (and its dependencies if required)

• ./compare_sizes.py: compare the sizes of the .eh_frame of a binary (and its dependencies) with the sizes of the .text of the generated ELFs.

• ./extract_pc.py: extracts a list of valid program counters of an ELF and produce a file as read by dwarf-assembly, deprecated.

• benching: all about benchmarking

• env: environment variables manager to ease the use of various eh_elfs in parallel, for experiments.

• shared: code shared between various subprojects

• src: the compiler code itself

• stack_walker: a primitive stack walker using eh_elfs

• stack_walker_libunwind: a primitive stack walker using vanilla libunwind

• stats: a statistics gathering module

• tests: some tests regarding eh_elfs, deprecated.

How to use

To compile eh_elfs for a given ELF file, say foo.bin, it is recommended to use generate_eh_elf.py. Help can be obtained with --help. A standard command is

./generate_eh_elf.py --deps --enable-deref-arg --global-switch -o eh_elfs foo.bin

This will compile foo.bin and all the shared objects it relies on into eh_elfs, in the directory ./eh_elfs, using a dereferencing argument (which is necessary for perf-eh_elfs).

Generate the intermediary C file

If you're curious about the intermediary C file generated for a given ELF file foo.bin, you must call dwarf-assembly directly. A parameter --help can be passed; a standard command is

./dwarf-assembly --global-switch --enable-deref-arg foo.bin

Beware! This will generate the C code on the standard output.