[PATCH] D117183: [CMake] Don't use -fno-semantic-interposition with Clang<=13

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added a reviewer: ljmf00.
Herald added subscribers: pengfei, mgorny.
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Clang 13 has a -fsanitize-coverage bug that incorrectly adding comdat to
dso_local functions in -fPIC mode. This can lead to `relocation R_X86_64_PC32
cannot be used against symbol` 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.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D117183

Files:
  llvm/cmake/modules/HandleLLVMOptions.cmake


Index: llvm/cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- llvm/cmake/modules/HandleLLVMOptions.cmake
+++ llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -315,12 +315,11 @@
     # 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 that -fsanitize-coverage may incorrectly add comdat to
+    # dso_local functions.
     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()


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