llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-bolt Author: Amir Ayupov (aaupov) <details> <summary>Changes</summary> Dead jump tables such as those arising from FIXED_PIC_BRANCH optimization don't need to be updated or moved. Further, if any jump table entry points to a block removed by unreachable code elimination, we would be unable to update it and jump table emission would fail. Identify non-referenced jump tables and delete them to prevent that. Test Plan: NFC for existing tests. --- Full diff: https://github.com/llvm/llvm-project/pull/91666.diff 1 Files Affected: - (modified) bolt/lib/Core/BinaryFunction.cpp (+20) ``````````diff diff --git a/bolt/lib/Core/BinaryFunction.cpp b/bolt/lib/Core/BinaryFunction.cpp index 11103f7bdce8..f74ecea8ac0a 100644 --- a/bolt/lib/Core/BinaryFunction.cpp +++ b/bolt/lib/Core/BinaryFunction.cpp @@ -1697,6 +1697,26 @@ void BinaryFunction::postProcessEntryPoints() { } void BinaryFunction::postProcessJumpTables() { + // Set of JTs accessed from this function. + std::unordered_set<uint64_t> LiveJTs; + for (auto &JTSite : JTSites) + LiveJTs.emplace(JTSite.second); + + // Remove dead jump tables (reference removed as a result of + // POSSIBLE_PIC_FIXED_BRANCH optimization). + for (auto JTI = JumpTables.begin(), JTE = JumpTables.end(); JTI != JTE; ) { + const uint64_t Address = JTI->first; + JumpTable *JT = JTI->second; + bool HasOneParent = JT->Parents.size() == 1; + if (LiveJTs.count(Address) == 0 && HasOneParent) { + BC.deregisterJumpTable(Address); + delete JT; + JTI = JumpTables.erase(JTI); + continue; + } + ++JTI; + } + // Create labels for all entries. for (auto &JTI : JumpTables) { JumpTable &JT = *JTI.second; `````````` </details> https://github.com/llvm/llvm-project/pull/91666 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
