Index: lib/CodeGen/CodeGenModule.h =================================================================== --- lib/CodeGen/CodeGenModule.h +++ lib/CodeGen/CodeGenModule.h @@ -1341,6 +1341,9 @@ void ConstructDefaultFnAttrList(StringRef Name, bool HasOptnone, bool AttrOnCallSite, llvm::AttrBuilder &FuncAttrs); + + bool needsUnwindTable(); + }; } // end namespace CodeGen } // end namespace clang Index: lib/CodeGen/CodeGenModule.cpp =================================================================== --- lib/CodeGen/CodeGenModule.cpp +++ lib/CodeGen/CodeGenModule.cpp @@ -865,13 +865,25 @@ return true; } +// This function needs an unwind table +bool CodeGenModule::needsUnwindTable() { + if (CodeGenOpts.UnwindTables) + return true; + + llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch(); + return hasUnwindExceptions (LangOpts) && Arch==llvm::Triple::arm; +} + void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, llvm::Function *F) { llvm::AttrBuilder B; - if (CodeGenOpts.UnwindTables) + // Set the attribute if the user requests it or if the language requiers it. + if (needsUnwindTable()) B.addAttribute(llvm::Attribute::UWTable); + // If the module doesn't support exceptions the function cannot throw. + // We can have a nothrow function even if unwind tables are required. if (!hasUnwindExceptions(LangOpts)) B.addAttribute(llvm::Attribute::NoUnwind);