forked from OSchip/llvm-project
4fbe33593c
See the updated linkonce_resolution_comdat.ll. For a local linkage GV in a non-prevailing COMDAT, it remains defined while its leader has been made available_externally. This violates the COMDAT rule that its members must be retained or discarded as a unit. To fix this, update the regular LTO change D34803 to track local linkage GlobalValues, and port the code to ThinLTO (GlobalAliases are not handled.) Fix https://github.com/llvm/llvm-project/issues/58215: as a size optimization, we place private `__profd_` in a COMDAT with a `__profc_` key. When FuncImport.cpp makes `__profc_` available_externally due to a non-prevailing COMDAT, `__profd_` incorrectly remains private. This change makes the `__profd_` available_externally. ``` cat > c.h <<'eof' extern void bar(); inline __attribute__((noinline)) void foo() {} eof cat > m1.cc <<'eof' #include "c.h" int main() { bar(); foo(); } eof cat > m2.cc <<'eof' #include "c.h" __attribute__((noinline)) void bar() { foo(); } eof clang -O2 -fprofile-generate=./t m1.cc m2.cc -flto -fuse-ld=lld -o t_gen rm -fr t && ./t_gen && llvm-profdata show -function=foo t/default_*.profraw # one _Z3foov clang -O2 -fprofile-generate=./t m1.cc m2.cc -flto=thin -fuse-ld=lld -o t_gen rm -fr t && ./t_gen && llvm-profdata show -function=foo t/default_*.profraw # one _Z3foov ``` Reviewed By: tejohnson Differential Revision: https://reviews.llvm.org/D135427 |
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