From 314ef7bafda9f507540f3294359f20ba7bcf7a8d Mon Sep 17 00:00:00 2001 From: Reid Kleckner Date: Sat, 1 Feb 2014 00:04:45 +0000 Subject: [ms-cxxabi] Use inalloca on win32 when passing non-trivial C++ objects When a non-trivial parameter is present, clang now gathers up all the parameters that lack inreg and puts them into a packed struct. MSVC always aligns each parameter to 4 bytes and no more, so this is a pretty simple struct to lay out. On win64, non-trivial records are passed indirectly. Prior to this change, clang was incorrectly using byval on win64. I'm able to self-host a working clang with this change and additional LLVM patches. Reviewers: rsmith Differential Revision: http://llvm-reviews.chandlerc.com/D2636 llvm-svn: 200597 --- clang/lib/CodeGen/CodeGenFunction.cpp | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'clang/lib/CodeGen/CodeGenFunction.cpp') diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp index 572f5ba..7d451e8 100644 --- a/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/clang/lib/CodeGen/CodeGenFunction.cpp @@ -276,6 +276,14 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { if (CGM.getCodeGenOpts().EmitDeclMetadata) EmitDeclMetadata(); + + for (SmallVectorImpl >::iterator + I = DeferredReplacements.begin(), + E = DeferredReplacements.end(); + I != E; ++I) { + I->first->replaceAllUsesWith(I->second); + I->first->eraseFromParent(); + } } /// ShouldInstrumentFunction - Return true if the current function should be @@ -592,6 +600,14 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, // Indirect aggregate return; emit returned value directly into sret slot. // This reduces code size, and affects correctness in C++. ReturnValue = CurFn->arg_begin(); + } else if (CurFnInfo->getReturnInfo().getKind() == ABIArgInfo::InAlloca && + !hasScalarEvaluationKind(CurFnInfo->getReturnType())) { + // Load the sret pointer from the argument struct and return into that. + unsigned Idx = CurFnInfo->getReturnInfo().getInAllocaFieldIndex(); + llvm::Function::arg_iterator EI = CurFn->arg_end(); + --EI; + llvm::Value *Addr = Builder.CreateStructGEP(EI, Idx); + ReturnValue = Builder.CreateLoad(Addr, "agg.result"); } else { ReturnValue = CreateIRTemp(RetTy, "retval"); -- cgit v1.1