diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/LTO/LTOBackend.cpp | 16 | ||||
| -rw-r--r-- | llvm/lib/Transforms/IPO/FunctionImport.cpp | 38 |
2 files changed, 32 insertions, 22 deletions
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp index c9d842147f8..49c0c2e15b3 100644 --- a/llvm/lib/LTO/LTOBackend.cpp +++ b/llvm/lib/LTO/LTOBackend.cpp @@ -401,18 +401,14 @@ Error lto::backend(Config &C, AddStreamFn AddStream, static void dropDeadSymbols(Module &Mod, const GVSummaryMapTy &DefinedGlobals, const ModuleSummaryIndex &Index) { - auto MaybeDrop = [&](GlobalValue &GV) { + std::vector<GlobalValue *> ReplacedGlobals; + for (auto &GV : Mod.global_values()) if (GlobalValueSummary *GVS = DefinedGlobals.lookup(GV.getGUID())) - if (!Index.isGlobalValueLive(GVS)) - convertToDeclaration(GV); - }; + if (!Index.isGlobalValueLive(GVS) && !convertToDeclaration(GV)) + ReplacedGlobals.push_back(&GV); - // Process functions and global now. - // FIXME: add support for aliases (needs support in convertToDeclaration). - for (auto &GV : Mod) - MaybeDrop(GV); - for (auto &GV : Mod.globals()) - MaybeDrop(GV); + for (GlobalValue *GV : ReplacedGlobals) + GV->eraseFromParent(); } Error lto::thinBackend(Config &Conf, unsigned Task, AddStreamFn AddStream, diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp index 37c4c21578c..a5903e27a9d 100644 --- a/llvm/lib/Transforms/IPO/FunctionImport.cpp +++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp @@ -613,7 +613,7 @@ llvm::EmitImportsFiles(StringRef ModulePath, StringRef OutputFilename, return std::error_code(); } -void llvm::convertToDeclaration(GlobalValue &GV) { +bool llvm::convertToDeclaration(GlobalValue &GV) { DEBUG(dbgs() << "Converting to a declaration: `" << GV.getName() << "\n"); if (Function *F = dyn_cast<Function>(&GV)) { F->deleteBody(); @@ -624,14 +624,24 @@ void llvm::convertToDeclaration(GlobalValue &GV) { V->setLinkage(GlobalValue::ExternalLinkage); V->clearMetadata(); V->setComdat(nullptr); - } else - // For now we don't resolve or drop aliases. Once we do we'll - // need to add support here for creating either a function or - // variable declaration, and return the new GlobalValue* for - // the caller to use. - // Support of dropping aliases is required for correct dead code - // elimination performed in thin LTO backends (see 'dropDeadSymbols'). - llvm_unreachable("Expected function or variable"); + } else { + GlobalValue *NewGV; + if (GV.getValueType()->isFunctionTy()) + NewGV = + Function::Create(cast<FunctionType>(GV.getValueType()), + GlobalValue::ExternalLinkage, "", GV.getParent()); + else + NewGV = + new GlobalVariable(*GV.getParent(), GV.getValueType(), + /*isConstant*/ false, GlobalValue::ExternalLinkage, + /*init*/ nullptr, "", + /*insertbefore*/ nullptr, GV.getThreadLocalMode(), + GV.getType()->getAddressSpace()); + NewGV->takeName(&GV); + GV.replaceAllUsesWith(NewGV); + return false; + } + return true; } /// Fixup WeakForLinker linkages in \p TheModule based on summary analysis. @@ -666,9 +676,13 @@ void llvm::thinLTOResolveWeakForLinkerModule( // interposable property and possibly get inlined. Simply drop // the definition in that case. if (GlobalValue::isAvailableExternallyLinkage(NewLinkage) && - GlobalValue::isInterposableLinkage(GV.getLinkage())) - convertToDeclaration(GV); - else { + GlobalValue::isInterposableLinkage(GV.getLinkage())) { + if (!convertToDeclaration(GV)) + // FIXME: Change this to collect replaced GVs and later erase + // them from the parent module once thinLTOResolveWeakForLinkerGUID is + // changed to enable this for aliases. + llvm_unreachable("Expected GV to be converted"); + } else { DEBUG(dbgs() << "ODR fixing up linkage for `" << GV.getName() << "` from " << GV.getLinkage() << " to " << NewLinkage << "\n"); GV.setLinkage(NewLinkage); |
