diff options
| author | Manman Ren <mren@apple.com> | 2013-03-20 16:59:38 +0000 |
|---|---|---|
| committer | Manman Ren <mren@apple.com> | 2013-03-20 16:59:38 +0000 |
| commit | 63fd408a61ae9b94e8d8a986832f526f7cdbfa84 (patch) | |
| tree | b69fb6c25f54302cff940596a27db5ebbadea3b9 /lib/CodeGen/CGClass.cpp | |
| parent | 54a38bd5cf243310290f34b43fc940a498a00f90 (diff) | |
Exploit this-return of a callsite in a this-return function.
For constructors/desctructors that return 'this', if there exists a callsite
that returns 'this' and is immediately before the return instruction, make
sure we are using the return value from the callsite.
We don't need to keep 'this' alive through the callsite. It also enables
optimizations in the backend, such as tail call optimization.
Updated from r177211.
rdar://12818789
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177541 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/CGClass.cpp')
| -rw-r--r-- | lib/CodeGen/CGClass.cpp | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/lib/CodeGen/CGClass.cpp b/lib/CodeGen/CGClass.cpp index 287d164cb9..2ececb0365 100644 --- a/lib/CodeGen/CGClass.cpp +++ b/lib/CodeGen/CGClass.cpp @@ -1666,8 +1666,11 @@ CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D, } // Non-trivial constructors are handled in an ABI-specific manner. - CGM.getCXXABI().EmitConstructorCall(*this, D, Type, ForVirtualBase, - Delegating, This, ArgBeg, ArgEnd); + llvm::Value *Callee = CGM.getCXXABI().EmitConstructorCall(*this, D, Type, + ForVirtualBase, Delegating, This, ArgBeg, ArgEnd); + if (CGM.getCXXABI().HasThisReturn(CurGD) && + CGM.getCXXABI().HasThisReturn(GlobalDecl(D, Type))) + CalleeWithThisReturn = Callee; } void @@ -1756,9 +1759,12 @@ CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor, EmitDelegateCallArg(DelegateArgs, param); } + llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(Ctor, CtorType); EmitCall(CGM.getTypes().arrangeCXXConstructorDeclaration(Ctor, CtorType), - CGM.GetAddrOfCXXConstructor(Ctor, CtorType), - ReturnValueSlot(), DelegateArgs, Ctor); + Callee, ReturnValueSlot(), DelegateArgs, Ctor); + if (CGM.getCXXABI().HasThisReturn(CurGD) && + CGM.getCXXABI().HasThisReturn(GlobalDecl(Ctor, CtorType))) + CalleeWithThisReturn = Callee; } namespace { @@ -1825,6 +1831,9 @@ void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD, EmitCXXMemberCall(DD, SourceLocation(), Callee, ReturnValueSlot(), This, VTT, getContext().getPointerType(getContext().VoidPtrTy), 0, 0); + if (CGM.getCXXABI().HasThisReturn(CurGD) && + CGM.getCXXABI().HasThisReturn(GlobalDecl(DD, Type))) + CalleeWithThisReturn = Callee; } namespace { |