tenfourfox/build/unix/elfhack
Cameron Kaiser c9b2922b70 hello FPR
2017-04-19 00:56:45 -07:00
..
inject hello FPR 2017-04-19 00:56:45 -07:00
dummy.c hello FPR 2017-04-19 00:56:45 -07:00
elf.cpp hello FPR 2017-04-19 00:56:45 -07:00
elfhack.cpp hello FPR 2017-04-19 00:56:45 -07:00
elfxx.h hello FPR 2017-04-19 00:56:45 -07:00
inject.c hello FPR 2017-04-19 00:56:45 -07:00
Makefile.in hello FPR 2017-04-19 00:56:45 -07:00
moz.build hello FPR 2017-04-19 00:56:45 -07:00
README hello FPR 2017-04-19 00:56:45 -07:00
test-array.c hello FPR 2017-04-19 00:56:45 -07:00
test-ctors.c hello FPR 2017-04-19 00:56:45 -07:00
test.c hello FPR 2017-04-19 00:56:45 -07:00

Elfhack is a program to optimize ELF binaries for size and cold startup
speed.

Presently, it is quite experimental, though it works well for the target
it was created for: Firefox's libxul.so.

Elfhack currently only does one thing: packing dynamic relocations ;
which ends up being a quite complex task, that can be summarized this
way:
- Remove RELATIVE relocations from the .rel.dyn/.rela.dyn section.
- Inject a small code able to apply relative relocations "by hand"
  after the .rel.dyn/.rela.dyn section.
- Inject a section containing relocative relocations in a different
  and more packed format, after the small code.
- Register the small code as DT_INIT function. Make the small code call
  what was initially the DT_INIT function, if there was one.
- Remove the hole between the new section containing relative
  relocations and the following sections, adjusting offsets and base
  addresses accordingly.
- Adjust PT_LOAD entries to fit new offsets, and add an additional
  PT_LOAD entry when that is necessary to handle the discrepancy between
  offsets and base addresses, meaning the section offsets may yet again
  need adjustments.
- Adjust various DT_* dynamic tags to fit the new ELF layout.
- Adjust section headers.
- Adjust ELF headers.

See http://glandium.org/blog/?p=1177#relocations for some figures.