diff options
| -rw-r--r-- | lib/LTO/LTO.cpp | 9 | ||||
| -rw-r--r-- | lib/Transforms/IPO/FunctionImport.cpp | 12 | ||||
| -rw-r--r-- | test/LTO/Resolution/X86/linker-redef-thin.ll | 16 |
3 files changed, 35 insertions, 2 deletions
diff --git a/lib/LTO/LTO.cpp b/lib/LTO/LTO.cpp index 68b8c9fcb93..8be5312b920 100644 --- a/lib/LTO/LTO.cpp +++ b/lib/LTO/LTO.cpp @@ -665,6 +665,15 @@ Error LTO::addThinLTO(BitcodeModule BM, ArrayRef<InputFile::Symbol> Syms, auto GUID = GlobalValue::getGUID(GlobalValue::getGlobalIdentifier( Sym.getIRName(), GlobalValue::ExternalLinkage, "")); ThinLTO.PrevailingModuleForGUID[GUID] = BM.getModuleIdentifier(); + + // For linker redefined symbols (via --wrap or --defsym) we want to + // switch the linkage to `weak` to prevent IPOs from happening. + // Find the summary in the module for this very GV and record the new + // linkage so that we can switch it when we import the GV. + if (Res.LinkerRedefined) + if (auto S = ThinLTO.CombinedIndex.findSummaryInModule( + GUID, BM.getModuleIdentifier())) + S->setLinkage(GlobalValue::WeakAnyLinkage); } } } diff --git a/lib/Transforms/IPO/FunctionImport.cpp b/lib/Transforms/IPO/FunctionImport.cpp index 6d34ab8b0d9..5e7cf436e2e 100644 --- a/lib/Transforms/IPO/FunctionImport.cpp +++ b/lib/Transforms/IPO/FunctionImport.cpp @@ -537,8 +537,6 @@ void llvm::thinLTOResolveWeakForLinkerModule( }; auto updateLinkage = [&](GlobalValue &GV) { - if (!GlobalValue::isWeakForLinker(GV.getLinkage())) - return; // See if the global summary analysis computed a new resolved linkage. const auto &GS = DefinedGlobals.find(GV.getGUID()); if (GS == DefinedGlobals.end()) @@ -546,6 +544,16 @@ void llvm::thinLTOResolveWeakForLinkerModule( auto NewLinkage = GS->second->linkage(); if (NewLinkage == GV.getLinkage()) return; + + // Switch the linkage to weakany if asked for, e.g. we do this for + // linker redefined symbols (via --wrap or --defsym). + if (NewLinkage == GlobalValue::WeakAnyLinkage) { + GV.setLinkage(NewLinkage); + return; + } + + if (!GlobalValue::isWeakForLinker(GV.getLinkage())) + return; // Check for a non-prevailing def that has interposable linkage // (e.g. non-odr weak or linkonce). In that case we can't simply // convert to available_externally, since it would lose the diff --git a/test/LTO/Resolution/X86/linker-redef-thin.ll b/test/LTO/Resolution/X86/linker-redef-thin.ll new file mode 100644 index 00000000000..ebaac8094e7 --- /dev/null +++ b/test/LTO/Resolution/X86/linker-redef-thin.ll @@ -0,0 +1,16 @@ +; RUN: opt -module-summary %s -o %t.o +; RUN: llvm-lto2 run -o %t1.o %t.o -r %t.o,patatino,pr +; RUN: llvm-readobj -t %t1.o.0 | FileCheck %s + +; CHECK: Name: patatino +; CHECK-NEXT: Value: +; CHECK-NEXT: Size: +; CHECK-NEXT: Binding: Weak +; CHECK-NEXT: Type: Function + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +define void @patatino() { + ret void +} |