From b17daf9ab790ae71aacad2cc4aa11cd8d86c25d1 Mon Sep 17 00:00:00 2001 From: Eli Friedman Date: Fri, 4 Dec 2009 02:43:40 +0000 Subject: Make functions returning a struct indirectly evaluate the returned struct directly into the sret pointer. This is an optimization in C, but is required for correctness in C++ for classes with a non-trivial copy constructor. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90526 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/CodeGenFunction.cpp | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'lib/CodeGen/CodeGenFunction.cpp') diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp index 1e952f9a7d..88f02a9738 100644 --- a/lib/CodeGen/CodeGenFunction.cpp +++ b/lib/CodeGen/CodeGenFunction.cpp @@ -179,9 +179,6 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, AllocaInsertPt->setName("allocapt"); ReturnBlock = createBasicBlock("return"); - ReturnValue = 0; - if (!RetTy->isVoidType()) - ReturnValue = CreateTempAlloca(ConvertType(RetTy), "retval"); Builder.SetInsertPoint(EntryBB); @@ -204,6 +201,19 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy, // FIXME: Leaked. CurFnInfo = &CGM.getTypes().getFunctionInfo(FnRetTy, Args); + + if (RetTy->isVoidType()) { + // Void type; nothing to return. + ReturnValue = 0; + } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::Indirect && + hasAggregateLLVMType(CurFnInfo->getReturnType())) { + // Indirect aggregate return; emit returned value directly into sret slot. + // This reduces code size, and is also affects correctness in C++. + ReturnValue = CurFn->arg_begin(); + } else { + ReturnValue = CreateTempAlloca(ConvertType(RetTy), "retval"); + } + EmitFunctionProlog(*CurFnInfo, CurFn, Args); // If any of the arguments have a variably modified type, make sure to -- cgit v1.2.3-70-g09d2