| //===- UniqueInternalLinkageNames.cpp - Unique Internal Linkage Sym Names -===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements unique naming of internal linkage symbols with option |
| // -funique-internal-linkage-symbols. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/Utils/UniqueInternalLinkageNames.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/IR/DebugInfoMetadata.h" |
| #include "llvm/IR/MDBuilder.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/MD5.h" |
| #include "llvm/Transforms/Utils/ModuleUtils.h" |
| |
| using namespace llvm; |
| |
| static bool uniqueifyInternalLinkageNames(Module &M) { |
| llvm::MD5 Md5; |
| Md5.update(M.getSourceFileName()); |
| llvm::MD5::MD5Result R; |
| Md5.final(R); |
| SmallString<32> Str; |
| llvm::MD5::stringifyResult(R, Str); |
| // Convert MD5hash to Decimal. Demangler suffixes can either contain numbers |
| // or characters but not both. |
| APInt IntHash = APInt(128, Str.str(), 16); |
| // Prepend "__uniq" before the hash for tools like profilers to understand that |
| // this symbol is of internal linkage type. |
| std::string ModuleNameHash = (Twine(".__uniq.") + Twine(IntHash.toString(10, false))).str(); |
| bool Changed = false; |
| MDBuilder MDB(M.getContext()); |
| |
| // Append the module hash to all internal linkage functions. |
| for (auto &F : M) { |
| if (F.hasInternalLinkage()) { |
| F.setName(F.getName() + ModuleNameHash); |
| F.addFnAttr("sample-profile-suffix-elision-policy", "selected"); |
| // Replace linkage names in the debug metadata. |
| if (DISubprogram *SP = F.getSubprogram()) { |
| if (SP->getRawLinkageName()) { |
| auto *Name = MDB.createString(F.getName()); |
| SP->replaceRawLinkageName(Name); |
| if (DISubprogram *SPDecl = SP->getDeclaration()) { |
| if (SPDecl->getRawLinkageName()) |
| SPDecl->replaceRawLinkageName(Name); |
| } |
| } |
| } |
| Changed = true; |
| } |
| } |
| |
| // Append the module hash to all internal linkage globals. |
| for (auto &GV : M.globals()) { |
| if (GV.hasInternalLinkage()) { |
| GV.setName(GV.getName() + ModuleNameHash); |
| Changed = true; |
| } |
| } |
| return Changed; |
| } |
| |
| namespace { |
| |
| // Legacy pass that provides a name to every anon globals. |
| class UniqueInternalLinkageNamesLegacyPass : public ModulePass { |
| |
| public: |
| /// Pass identification, replacement for typeid |
| static char ID; |
| |
| /// Specify pass name for debug output |
| StringRef getPassName() const override { |
| return "Unique Internal Linkage Names"; |
| } |
| |
| explicit UniqueInternalLinkageNamesLegacyPass() : ModulePass(ID) { |
| initializeUniqueInternalLinkageNamesLegacyPassPass( |
| *PassRegistry::getPassRegistry()); |
| } |
| |
| bool runOnModule(Module &M) override { |
| return uniqueifyInternalLinkageNames(M); |
| } |
| }; |
| |
| char UniqueInternalLinkageNamesLegacyPass::ID = 0; |
| } // anonymous namespace |
| |
| PreservedAnalyses |
| UniqueInternalLinkageNamesPass::run(Module &M, ModuleAnalysisManager &AM) { |
| if (!uniqueifyInternalLinkageNames(M)) |
| return PreservedAnalyses::all(); |
| |
| return PreservedAnalyses::none(); |
| } |
| |
| INITIALIZE_PASS_BEGIN(UniqueInternalLinkageNamesLegacyPass, |
| "unique-internal-linkage-names", |
| "Uniqueify internal linkage names", false, false) |
| INITIALIZE_PASS_END(UniqueInternalLinkageNamesLegacyPass, |
| "unique-internal-linkage-names", |
| "Uniqueify Internal linkage names", false, false) |
| |
| namespace llvm { |
| ModulePass *createUniqueInternalLinkageNamesPass() { |
| return new UniqueInternalLinkageNamesLegacyPass(); |
| } |
| } // namespace llvm |