gecko-dev

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History

Mike Hommey 15a3c672da Bug 635966 - Avoid elfhack failure with llvm. r=khuey,a=shaver		2011-02-23 10:06:26 +01:00
..
dummy.c	Bug 628988 part 1 - Modify elfhack test so that the executable actively calls something from the library. r=tglek,a=sdwilsh	2011-01-28 09:22:58 +01:00
elf.cpp	Bug 629635 part 4 - Make elfhack keep PT_GNU_RELRO segments as they were originally. r=tglek,a=blocking2.0:final	2011-02-12 10:28:34 +01:00
elfhack.cpp	Bug 632920 part 2 - Add support for R_ARM_THM_JUMP24 relocation in elfhack. r=tglek,a=bsmedberg	2011-02-16 17:27:35 +01:00
elfxx.h	Bug 629635 part 4 - Make elfhack keep PT_GNU_RELRO segments as they were originally. r=tglek,a=blocking2.0:final	2011-02-12 10:28:34 +01:00
inject.c
Makefile.in	Bug 635966 - Avoid elfhack failure with llvm. r=khuey,a=shaver	2011-02-23 10:06:26 +01:00
README
test.c	Bug 628988 part 1 - Modify elfhack test so that the executable actively calls something from the library. r=tglek,a=sdwilsh	2011-01-28 09:22:58 +01:00

README

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.