Author: hans Date: Wed Jan 23 08:24:00 2019 New Revision: 351963 URL: http://llvm.org/viewvc/llvm-project?rev=351963&view=rev Log: Merging r351898: ------------------------------------------------------------------------ r351898 | pcc | 2019-01-23 00:51:35 +0100 (Wed, 23 Jan 2019) | 13 lines
COFF, ELF: Adjust ICF hash computation to account for self relocations. It turns out that sections in PGO instrumented object files on Windows contain a large number of relocations pointing to themselves. With r347429 this can cause many sections to receive the same hash (usually zero) as a result of a section's hash being xor'ed with itself. This patch causes the COFF and ELF linkers to avoid this problem by adding the hash of the relocated section instead of xor'ing it. On my machine this causes the regressing test case provided by Mozilla to terminate in 2m41s. Differential Revision: https://reviews.llvm.org/D56955 ------------------------------------------------------------------------ Modified: lld/branches/release_80/ (props changed) lld/branches/release_80/COFF/ICF.cpp lld/branches/release_80/ELF/ICF.cpp Propchange: lld/branches/release_80/ ------------------------------------------------------------------------------ --- svn:mergeinfo (original) +++ svn:mergeinfo Wed Jan 23 08:24:00 2019 @@ -1 +1 @@ -/lld/trunk:351326,351335 +/lld/trunk:351326,351335,351898 Modified: lld/branches/release_80/COFF/ICF.cpp URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_80/COFF/ICF.cpp?rev=351963&r1=351962&r2=351963&view=diff ============================================================================== --- lld/branches/release_80/COFF/ICF.cpp (original) +++ lld/branches/release_80/COFF/ICF.cpp Wed Jan 23 08:24:00 2019 @@ -272,7 +272,7 @@ void ICF::run(ArrayRef<Chunk *> Vec) { uint32_t Hash = SC->Class[1]; for (Symbol *B : SC->symbols()) if (auto *Sym = dyn_cast_or_null<DefinedRegular>(B)) - Hash ^= Sym->getChunk()->Class[1]; + Hash += Sym->getChunk()->Class[1]; // Set MSB to 1 to avoid collisions with non-hash classs. SC->Class[0] = Hash | (1U << 31); }); Modified: lld/branches/release_80/ELF/ICF.cpp URL: http://llvm.org/viewvc/llvm-project/lld/branches/release_80/ELF/ICF.cpp?rev=351963&r1=351962&r2=351963&view=diff ============================================================================== --- lld/branches/release_80/ELF/ICF.cpp (original) +++ lld/branches/release_80/ELF/ICF.cpp Wed Jan 23 08:24:00 2019 @@ -432,7 +432,7 @@ static void combineRelocHashes(InputSect Symbol &S = IS->template getFile<ELFT>()->getRelocTargetSym(Rel); if (auto *D = dyn_cast<Defined>(&S)) if (auto *RelSec = dyn_cast_or_null<InputSection>(D->Section)) - Hash ^= RelSec->Class[1]; + Hash += RelSec->Class[1]; } // Set MSB to 1 to avoid collisions with non-hash IDs. IS->Class[0] = Hash | (1U << 31); _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
