en Copyright 2015 Java http://172.16.0.5:8080/history/llvm-project-15.0.7/llvm/test/Transforms/PGOProfile/comdat.ll#9ab9a959 [InstrProfiling] Keep profd non-private for non-renamable comdat functionsThe NS==0 condition used by D103717 missed a corner case: if the current copydoes not have a hash suffix (e.g. weak_odr), a copy with value profiling (with adifferent CFG) may exist. This is super rare, but is possible with pre-inliningPGO instrumentation (which can make a weak_odr function inlines its calleesdifferently, sometimes with value profiling while sometimes without).If the current copy with private profd is prevailing, the non-prevailing copymay get an undefined symbol if a caller inlining the non-prevailing functionreferences its profd. If the other copy with non-private profd is prevailing,the current copy may cause a "relocation to discarded section" linker error.The fix is straightforward: just keep non-private profd in such a `DataReferencedByCode` case.With this change, a stage 2 (`-DLLVM_TARGETS_TO_BUILD=X86 -DLLVM_BUILD_INSTRUMENTED=IR`)clang is 0.08% larger (172431496/172286720-1).`stat -c %s **/*.o | awk '{s+=$1}END{print s}' is 0.026% larger.The majority of D103717's benefits remains.Reviewed By: xurDifferential Revision: https://reviews.llvm.org/D108432 List of files: /llvm-project-15.0.7/llvm/test/Transforms/PGOProfile/comdat.ll Wed, 25 Aug 2021 03:14:02 +0000 Fangrui Song <i@maskray.me> http://172.16.0.5:8080/history/llvm-project-15.0.7/llvm/test/Transforms/PGOProfile/comdat.ll#32e2326c Revert D108432 "[InstrProfiling] Keep profd non-private for non-renamable comdat functions"This reverts commit f653beea88d2684cdc8117e662b321ba04666771.It broke Windows coverage-inline.cpp because link.exe has a limitationthat external symbols in IMAGE_COMDAT_SELECT_ASSOCIATIVE don't work.It essentially dropped the previous size optimization for coveragebecause coverage doesn't rename comdat by default.Needs more investigation what we should do. List of files: /llvm-project-15.0.7/llvm/test/Transforms/PGOProfile/comdat.ll Wed, 25 Aug 2021 02:16:07 +0000 Fangrui Song <i@maskray.me> http://172.16.0.5:8080/history/llvm-project-15.0.7/llvm/test/Transforms/PGOProfile/comdat.ll#f653beea [InstrProfiling] Keep profd non-private for non-renamable comdat functionsThe NS==0 condition used by D103717 missed a corner case: if the current copydoes not have a hash suffix (e.g. weak_odr), a copy with value profiling (with adifferent CFG) may exist. This is super rare, but is possible with pre-inliningPGO instrumentation (which can make a weak_odr function inlines its calleesdifferently, sometimes with value profiling while sometimes without).If the current copy with private profd is prevailing, the non-prevailing copymay get an undefined symbol if a caller inlining the non-prevailing functionreferences its profd. If the other copy with non-private profd is prevailing,the current copy may cause a "relocation to discarded section" linker error.The fix is straightforward: just keep non-private profd in this case.With this change, a stage 2 (`-DLLVM_TARGETS_TO_BUILD=X86 -DLLVM_BUILD_INSTRUMENTED=IR`)clang is 0.08% larger (172431496/172286720-1).`stat -c %s **/*.o | awk '{s+=$1}END{print s}' is 0.026% larger.The majority of D103717's benefits remains.Reviewed By: xurDifferential Revision: https://reviews.llvm.org/D108432 List of files: /llvm-project-15.0.7/llvm/test/Transforms/PGOProfile/comdat.ll Tue, 24 Aug 2021 22:59:35 +0000 Fangrui Song <i@maskray.me>