gecko-dev/build/unix/elfhack
Ms2ger ce50a0bf86 Bug 1194603 - Remove INTERNAL_TOOLS; r=mshal
Its only purpose is to disable PGO. Where that was not already explicitly done,
or irrelevant (because the directory only contains python), I disabled it in
moz.build.
2015-09-10 13:49:19 +02:00
..
inject Bug 1194603 - Remove INTERNAL_TOOLS; r=mshal 2015-09-10 13:49:19 +02:00
Makefile.in Bug 1194603 - Remove INTERNAL_TOOLS; r=mshal 2015-09-10 13:49:19 +02:00
README
dummy.c Bug 716295 part 6 - Create elfhack tests for both DT_INIT and DT_INIT_ARRAY. r=nfroyd 2012-08-09 16:34:26 +02:00
elf.cpp Bug 784739 - Switch from NULL to nullptr in build/; r=ehsan 2013-11-11 14:13:38 -05:00
elfhack.cpp Bug 982014 - Fix what sections are copied from injection object after bug 932737. r=nfroyd 2014-04-04 14:56:36 +09:00
elfxx.h Bug 1120062 - Part 1: Remove most Nullptr.h includes. r=waldo 2015-01-11 11:34:52 +09:00
inject.c Bug 932737 - Change elfhack such that it doesn't require two injection objects. r=nfroyd 2013-11-02 08:47:24 +09:00
moz.build Bug 1167474 - Remove ELFHACK_BUILD hack. r=mshal 2015-05-26 16:17:55 +09:00
test-array.c Bug 716295 part 6 - Create elfhack tests for both DT_INIT and DT_INIT_ARRAY. r=nfroyd 2012-08-09 16:34:26 +02:00
test-ctors.c Bug 716295 part 6 - Create elfhack tests for both DT_INIT and DT_INIT_ARRAY. r=nfroyd 2012-08-09 16:34:26 +02:00
test.c Bug 654087 - Don't error out on gold special treatment of PT_TLS segment memsize. r=nfroyd 2013-01-16 09:15:07 +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.