llvm-project/lld
Fangrui Song bf535ac4a2 [ELF][AArch64] Support R_AARCH64_{CALL26,JUMP26} range extension thunks with addends
Fixes AArch64 part of PR40438

The current range extension thunk framework does not handle a relocation
relative to a STT_SECTION symbol with a non-zero addend, which may be
used by jumps/calls to local functions on some RELA targets (AArch64,
powerpc ELFv1, powerpc64 ELFv2, etc).  See PR40438 and the following
code for examples:

  // clang -target $target a.cc
  // .text.cold may be placed in a separate output section.
  // The distance between bar in .text.cold and foo in .text may be larger than 128MiB.
  static void foo() {}
  __attribute__((section(".text.cold"))) static int bar() { foo(); return
  0; }
  __attribute__((used)) static int dummy = bar();

This patch makes such thunks with addends work for AArch64. The target
independent part can be reused by PPC in the future.

On REL targets (ARM, MIPS), jumps/calls are not represented as
STT_SECTION + non-zero addend (see
MCELFObjectTargetWriter::needsRelocateWithSymbol), so they don't need
this feature, but we need to make sure this patch does not affect them.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D70637
2019-12-02 10:07:24 -08:00
..
COFF [LLD] Add a default copy constructor to avoid warnings 2019-11-25 14:09:16 -06:00
Common LLD: Don't use the stderrOS stream in link before it's reassigned. 2019-11-21 10:55:03 -05:00
ELF [ELF][AArch64] Support R_AARCH64_{CALL26,JUMP26} range extension thunks with addends 2019-12-02 10:07:24 -08:00
MinGW LLD: Don't use the stderrOS stream in link before it's reassigned. 2019-11-21 10:55:03 -05:00
cmake/modules [CMake] Properly conditionalize installation of lld libraries 2018-03-09 13:09:36 +00:00
docs [lld] [ELF] Add '-z nognustack' opt to suppress emitting PT_GNU_STACK 2019-10-29 17:54:23 +01:00
include/lld LLD: Don't use the stderrOS stream in link before it's reassigned. 2019-11-21 10:55:03 -05:00
lib LLD: Don't use the stderrOS stream in link before it's reassigned. 2019-11-21 10:55:03 -05:00
test [ELF][AArch64] Support R_AARCH64_{CALL26,JUMP26} range extension thunks with addends 2019-12-02 10:07:24 -08:00
tools/lld Make it possible to redirect not only errs() but also outs() 2019-11-18 11:18:06 +09:00
unittests Make it possible to redirect not only errs() but also outs() 2019-11-18 11:18:06 +09:00
utils Python 2/3 compatibility 2019-03-20 07:42:13 +00:00
wasm LLD: Don't use the stderrOS stream in link before it's reassigned. 2019-11-21 10:55:03 -05:00
.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.