From f21bca02f7a900a9e8253d05682e7316e06afbea Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Thu, 22 Aug 2019 20:47:12 +0000 Subject: [Clang][CodeGen] set alias linkage on QualType Summary: It seems that CodeGen was always using ExternalLinkage when emitting a GlobalDecl with __attribute__((alias)). This leads to symbol redefinitions (ODR) that cause failures at link time for static aliases. This is readily attempting to link an ARM (32b) allyesconfig Linux kernel built with Clang. Reported-by: nathanchance Suggested-by: ihalip Link: https://bugs.llvm.org/show_bug.cgi?id=42377 Link: https://github.com/ClangBuiltLinux/linux/issues/631 Reviewers: rsmith, aaron.ballman, erichkeane Reviewed By: aaron.ballman Subscribers: javed.absar, kristof.beyls, cfe-commits, srhines, ihalip, nathanchance Tags: #clang Differential Revision: https://reviews.llvm.org/D66492 llvm-svn: 369705 --- clang/lib/CodeGen/CodeGenModule.cpp | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'clang/lib/CodeGen/CodeGenModule.cpp') diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index 0f7ac2a20239..3dc40a84868f 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -4363,17 +4363,22 @@ void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) { // Create a reference to the named value. This ensures that it is emitted // if a deferred decl. llvm::Constant *Aliasee; - if (isa(DeclTy)) + llvm::GlobalValue::LinkageTypes LT; + if (isa(DeclTy)) { Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GD, /*ForVTable=*/false); - else + LT = getFunctionLinkage(GD); + } else { Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), llvm::PointerType::getUnqual(DeclTy), /*D=*/nullptr); + LT = getLLVMLinkageVarDefinition(cast(GD.getDecl()), + D->getType().isConstQualified()); + } // Create the new alias itself, but don't set a name yet. - auto *GA = llvm::GlobalAlias::create( - DeclTy, 0, llvm::Function::ExternalLinkage, "", Aliasee, &getModule()); + auto *GA = + llvm::GlobalAlias::create(DeclTy, 0, LT, "", Aliasee, &getModule()); if (Entry) { if (GA->getAliasee() == Entry) { -- cgit v1.2.3