llvm-project/lld
Fangrui Song fc0aa8424c [ELF] Check COMMON symbols for PROVIDE and don't redefine COMMON symbols edata/end/etext
In GNU ld, the definition precedence is: regular symbol assignment > relocatable object definition > `PROVIDE` symbol assignment.

GNU ld's internal linker scripts define the non-reserved (by C and C++)
edata/end/etext with `PROVIDE` so the relocatable object definition takes
precedence. This makes sense because `int end;` is valid.

We currently redefine such symbols if they are COMMON, but not if they are
regular definitions, so `int end;` with -fcommon is essentially a UB in ld.lld.
Fix this (also improve consistency and match GNU ld) by using the
`isDefined` code path for `isCommon`. In GNU ld, reserved identifiers like
`__ehdr_start` do not use `PROVIDE`, while we treat them all as `PROVIDE`, this
seems fine.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D120389
2022-02-23 10:15:42 -08:00
..
COFF Cleanup llvm/DebugInfo/PDB headers 2022-02-23 10:31:34 +01:00
Common [lld] Make error handling functions opaque 2022-02-17 11:54:57 -08:00
ELF [ELF] Check COMMON symbols for PROVIDE and don't redefine COMMON symbols edata/end/etext 2022-02-23 10:15:42 -08:00
MachO [lld-macho][nfc] Refactor MarkLive 2022-02-23 08:58:26 -05:00
MinGW [LLD][MinGW] Add --heap argument support 2022-01-30 00:01:45 +02:00
cmake/modules [CMake] Factor out config prefix finding logic 2022-01-07 20:16:18 +00:00
docs [ELF] Support (TYPE=<value>) to customize the output section type 2022-02-17 12:10:58 -08:00
include/lld [lld] Make error handling functions opaque 2022-02-17 11:54:57 -08:00
test [ELF] Check COMMON symbols for PROVIDE and don't redefine COMMON symbols edata/end/etext 2022-02-23 10:15:42 -08:00
tools/lld [LLD] Fix issue in HIP due to unspecified order of evaluation of the function object 2022-02-08 19:12:15 -05:00
utils
wasm [lld][WebAssembly] Apply global relocs before data relocs 2022-02-16 14:30:39 -08:00
.clang-format
.clang-tidy NFC: .clang-tidy: Inherit configs from parents to improve maintainability 2021-06-08 08:25:59 -07:00
.gitignore
CMakeLists.txt [lld] Require C++14 in LLD standalone build 2022-02-22 18:15:29 -05:00
CODE_OWNERS.TXT Add code owners of new MachO port 2020-09-02 19:32:12 -07:00
LICENSE.TXT
README.md [doc] Place sha256 in lld/README.md into backticks 2021-01-12 10:19:40 -08:00

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.