llvm/lld
Fangrui Song dccd061302 [ELF] Suppress "duplicate symbol" when resolving STB_WEAK and STB_GNU_UNIQUE in different COMDATs
```
template <typename T> struct A {
  A() {}
  int value = 0;
};

template <typename Value> struct B {
  static A<int> a;
};

template <typename Value> A<int> B<Value>::a;

inline int foo() {
  return B<int>::a.value;
}
```

```
clang++ -c -fno-pic a.cc -o weak.o
g++ -c -fno-pic a.cc -o unique.o  # --enable-gnu-unique-object

# Duplicate symbol error. In postParse, we do not check `sym.binding`
ld.lld -e 0 weak.o unique.o
```

Mixing GCC and Clang object files in this case is not ideal. .bss._ZGVN1BIiE1aE
has different COMDAT groups. It appears to work in practice because the guard
variable prevents harm due to double initialization.

For the linker, we just stick with the rule that a weak binding does not cause
"duplicate symbol" errors.

Close https://github.com/llvm/llvm-project/issues/58232

Differential Revision: https://reviews.llvm.org/D136381

(cherry picked from commit 0051b6bb78772b0658f28e5f31ddf91c1589aab5)
2022-10-24 13:49:35 +02:00
..
cmake/modules [CMake] Fix add_subdirectory llvm builds 2022-07-26 11:24:23 +02:00
COFF [LLD][COFF] Fix writing a map file when range extension thunks are inserted 2022-09-12 12:54:42 +02:00
Common
docs [DOCS] Minor fixes and removals of WIP warnings 2022-09-04 16:48:01 +02:00
ELF [ELF] Suppress "duplicate symbol" when resolving STB_WEAK and STB_GNU_UNIQUE in different COMDATs 2022-10-24 13:49:35 +02:00
include/lld/Common [NFC][lld] Fix typos to test commit access 2022-06-24 00:19:18 +02:00
MachO [MachO] Don't fold compact unwind entries with LSDA 2022-09-14 08:14:57 +02:00
MinGW [LLD] [MinGW] Implement the --exclude-symbols option 2022-08-12 08:36:08 +02:00
test [ELF] Suppress "duplicate symbol" when resolving STB_WEAK and STB_GNU_UNIQUE in different COMDATs 2022-10-24 13:49:35 +02:00
tools/lld [LLD][ELF] Add FORCE_LLD_DIAGNOSTICS_CRASH to force LLD to crash 2022-07-05 09:43:09 +01:00
utils
wasm Use any_of (NFC) 2022-07-22 01:05:17 -07:00
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [cmake] Don't export LLVM_TOOLS_INSTALL_DIR anymore 2022-07-21 19:04:00 +00:00
CODE_OWNERS.TXT
LICENSE.TXT
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.