The Tor Browser: build/unix/elfhack/README@129ffea94266

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

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

     2 speed.

     4 Presently, it is quite experimental, though it works well for the target

     5 it was created for: Firefox's libxul.so.

     7 Elfhack currently only does one thing: packing dynamic relocations ;

     8 which ends up being a quite complex task, that can be summarized this

     9 way:

    10 - Remove RELATIVE relocations from the .rel.dyn/.rela.dyn section.

    11 - Inject a small code able to apply relative relocations "by hand"

    12   after the .rel.dyn/.rela.dyn section.

    13 - Inject a section containing relocative relocations in a different

    14   and more packed format, after the small code.

    15 - Register the small code as DT_INIT function. Make the small code call

    16   what was initially the DT_INIT function, if there was one.

    17 - Remove the hole between the new section containing relative

    18   relocations and the following sections, adjusting offsets and base

    19   addresses accordingly.

    20 - Adjust PT_LOAD entries to fit new offsets, and add an additional

    21   PT_LOAD entry when that is necessary to handle the discrepancy between

    22   offsets and base addresses, meaning the section offsets may yet again

    23   need adjustments.

    24 - Adjust various DT_* dynamic tags to fit the new ELF layout.

    25 - Adjust section headers.

    26 - Adjust ELF headers.

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

The Tor Browser / file revision

build/unix/elfhack/README@129ffea94266

build/unix/elfhack/README