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Fangrui Song 2d337fdc95 Reland D65242 "[ELF] More dynamic relocation packing"" 
This fixed a bug in r369488. When config->isRela is false, i->r_addend
is not initialized (see encodeDynamicReloc). So we should check
config->isRela before accessing r_addend:

- if (j - i < 3 || i->r_addend)
+ if (j - i < 3 || (config->isRela && i->r_addend != 0))

Original description:

Currently, with Android dynamic relocation packing, only relative
relocations are grouped together. This patch implements similar
packing for non-relative relocations.

The implementation groups non-relative relocations with the same
r_info and r_addend, if using RELA. By requiring a minimum group
size of 3, this achieves smaller relocation sections. Building Android
for an ARM32 device, I see the total size of /system/lib decrease by
392 KB.

Grouping by r_info also allows the runtime dynamic linker to implement
an 1-entry cache to reduce the number of symbol lookup required. With
such 1-entry cache implemented on Android, I'm seeing 10% to 20%
reduction in total time spent in runtime linker for several executables
that I tested.

As a simple correctness check, I've also built x86_64 Android and booted
successfully.

Differential Revision: https://reviews.llvm.org/D65242
Patch by Vic Yang

llvm-svn: 369507
 		2019-08-21 09:21:37 +00:00
..
COFF [COFF] Check errorCount before committing the output file 2019-08-20 21:08:14 +00:00
Common [ELF] For VS-style diagnostics, prefer printing full paths in the header. 2019-08-09 08:29:03 +00:00
ELF Reland D65242 "[ELF] More dynamic relocation packing"" 2019-08-21 09:21:37 +00:00
MinGW [MinGW] Correct handling different forms of a few options 2019-08-14 09:35:44 +00:00
cmake/modules [CMake] Properly conditionalize installation of lld libraries 2018-03-09 13:09:36 +00:00
docs Bump the trunk version to 10.0.0svn 2019-07-18 11:51:05 +00:00
include/lld [LLD] Migrate llvm::make_unique to std::make_unique 2019-08-14 22:28:17 +00:00
lib [LLD] Migrate llvm::make_unique to std::make_unique 2019-08-14 22:28:17 +00:00
test Reland D65242 "[ELF] More dynamic relocation packing"" 2019-08-21 09:21:37 +00:00
tools/lld Fix build breakage on Darwin. 2019-07-11 06:12:18 +00:00
unittests Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
utils Python 2/3 compatibility 2019-03-20 07:42:13 +00:00
wasm [WebAssembly][lld] Fix crash when applying relocations to debug sections 2019-08-20 18:39:24 +00:00
.arcconfig
…
.clang-format
…
.gitignore
…
CMakeLists.txt [CMake] Don't set Python_ADDITIONAL_VERSIONS 2019-07-18 15:17:42 +00:00
CODE_OWNERS.TXT
…
LICENSE.TXT Fix typos throughout the license files that somehow I and my reviewers 2019-01-21 09:52:34 +00:00
README.md
…

README.md

LLVM Linker (lld)

This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.

lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.

Benchmarking

In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.

It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz

The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f.