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authorFangrui Song <i@maskray.me>2022-01-13 15:38:02 -0800
committerTom Stellard <tstellar@redhat.com>2022-01-20 13:29:49 -0800
commit6349865a8f3751a651f9451eac0405e01ee03a11 (patch)
tree39fb35035dc82ca7a620c90239e2d46e7b1fe13a
parentb3dcd156472fbea65dd002cd670c5ae96de0d438 (diff)
downloadllvm-6349865a8f3751a651f9451eac0405e01ee03a11.tar.gz
[CMake] Don't use -fno-semantic-interposition with Clang<=13
Clang 13 has a -fsanitize-coverage -fno-semantic-interposition bug (D117190) which may lead to `relocation R_X86_64_PC32 cannot be used against symbol` linker error in -DLLVM_USE_SANITIZE_COVERAGE=ON build when a shared object is built (e.g. -DLLVM_BUILD_LLVM_DYLIB=on). For simplicity, just disallow Clang 13 entirely. Note: GCC -fPIC performance benefits from -fno-semantic-interposition dramatically. Clang benefits little. Using this option is more for a dogfood purpose to test correctness of this option, because in the wild some important packages like CPython uses this option. Differential Revision: https://reviews.llvm.org/D117183 (cherry picked from commit 1661c8cfcd6b286a1b5a599544afd87aa6b90243)
-rw-r--r--llvm/cmake/modules/HandleLLVMOptions.cmake7
1 files changed, 3 insertions, 4 deletions
diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index 0c3419390c27..cfcbb8f8aec3 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -316,12 +316,11 @@ if( LLVM_ENABLE_PIC )
# Note: GCC<10.3 has a bug on SystemZ.
#
# Note: Clang allows IPO for -fPIC so this optimization is less effective.
- # Older Clang may support -fno-semantic-interposition but it used local
- # aliases to optimize global variables, which is incompatible with copy
- # relocations due to -fno-pic.
+ # Clang 13 has a bug related to -fsanitize-coverage
+ # -fno-semantic-interposition (https://reviews.llvm.org/D117183).
if ((CMAKE_COMPILER_IS_GNUCXX AND
NOT (LLVM_NATIVE_ARCH STREQUAL "SystemZ" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 10.3))
- OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_VERSION GREATER_EQUAL 13))
+ OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_VERSION GREATER_EQUAL 14))
add_flag_if_supported("-fno-semantic-interposition" FNO_SEMANTIC_INTERPOSITION)
endif()
endif()