Index: lib/CodeGen/CodeGenModule.h =================================================================== --- lib/CodeGen/CodeGenModule.h +++ lib/CodeGen/CodeGenModule.h @@ -1334,6 +1334,11 @@ void ConstructDefaultFnAttrList(StringRef Name, bool HasOptnone, bool AttrOnCallSite, llvm::AttrBuilder &FuncAttrs); + + /// Check whether the attribute UWTable must be set to emit the unwind table + /// for exceptions + bool NeedsUnwindTable(); + }; } // end namespace CodeGen Index: lib/CodeGen/CodeGenModule.cpp =================================================================== --- lib/CodeGen/CodeGenModule.cpp +++ lib/CodeGen/CodeGenModule.cpp @@ -914,13 +914,32 @@ return true; } +// This function needs an unwind table +bool CodeGenModule::NeedsUnwindTable() { + if (CodeGenOpts.UnwindTables) + return true; + + // xxx checkarm eabi needs to emit the nowind attribute. + // implement function ins ARM.cpp + const llvm::Triple T = Context.getTargetInfo().getTriple(); + if (hasUnwindExceptions (LangOpts) + && (T.isARM() || T.isThumb ()) + && (T.getEnvironment() == llvm::Triple::EABI)) + return true; + + return false; +} + 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);