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gecko-dev/build/unix/elfhack
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Mike Hommey 89d385a324 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
..
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 716295 part 4 - Interpose elfhack injected code in DT_INIT_ARRAY's first entry when possible. r=nfroyd 2012-08-09 16:34:25 +02:00
elfhack.cpp Bug 716295 part 5 - Add support for R_ARM_THM_CALL relocations. r=nfroyd 2012-08-09 16:34:25 +02:00
elfxx.h Bug 716295 part 4 - Interpose elfhack injected code in DT_INIT_ARRAY's first entry when possible. r=nfroyd 2012-08-09 16:34:25 +02:00
inject.c Bug 716478 - update licence to MPL 2. 2012-05-21 12:12:37 +01:00
Makefile.in 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
README
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 716295 part 6 - Create elfhack tests for both DT_INIT and DT_INIT_ARRAY. r=nfroyd 2012-08-09 16:34:26 +02:00

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.