Properly assemble PHIs after a null-checked invoke of objc_msgSend.
rdar://12046763
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174946 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 2d67a77..b618527 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -1547,16 +1547,18 @@
/// value.
struct NullReturnState {
llvm::BasicBlock *NullBB;
- llvm::BasicBlock *callBB;
- NullReturnState() : NullBB(0), callBB(0) {}
+ NullReturnState() : NullBB(0) {}
+ /// Perform a null-check of the given receiver.
void init(CodeGenFunction &CGF, llvm::Value *receiver) {
- // Make blocks for the null-init and call edges.
- NullBB = CGF.createBasicBlock("msgSend.nullinit");
- callBB = CGF.createBasicBlock("msgSend.call");
+ // Make blocks for the null-receiver and call edges.
+ NullBB = CGF.createBasicBlock("msgSend.null-receiver");
+ llvm::BasicBlock *callBB = CGF.createBasicBlock("msgSend.call");
// Check for a null receiver and, if there is one, jump to the
- // null-init test.
+ // null-receiver block. There's no point in trying to avoid it:
+ // we're always going to put *something* there, because otherwise
+ // we shouldn't have done this null-check in the first place.
llvm::Value *isNull = CGF.Builder.CreateIsNull(receiver);
CGF.Builder.CreateCondBr(isNull, NullBB, callBB);
@@ -1564,25 +1566,29 @@
CGF.EmitBlock(callBB);
}
+ /// Complete the null-return operation. It is valid to call this
+ /// regardless of whether 'init' has been called.
RValue complete(CodeGenFunction &CGF, RValue result, QualType resultType,
const CallArgList &CallArgs,
const ObjCMethodDecl *Method) {
+ // If we never had to do a null-check, just use the raw result.
if (!NullBB) return result;
+
+ // The continuation block. This will be left null if we don't have an
+ // IP, which can happen if the method we're calling is marked noreturn.
+ llvm::BasicBlock *contBB = 0;
- llvm::Value *NullInitPtr = 0;
- if (result.isScalar() && !resultType->isVoidType()) {
- NullInitPtr = CGF.CreateTempAlloca(result.getScalarVal()->getType());
- CGF.Builder.CreateStore(result.getScalarVal(), NullInitPtr);
+ // Finish the call path.
+ llvm::BasicBlock *callBB = CGF.Builder.GetInsertBlock();
+ if (callBB) {
+ contBB = CGF.createBasicBlock("msgSend.cont");
+ CGF.Builder.CreateBr(contBB);
}
- // Finish the call path.
- llvm::BasicBlock *contBB = CGF.createBasicBlock("msgSend.cont");
- if (CGF.HaveInsertPoint()) CGF.Builder.CreateBr(contBB);
-
- // Emit the null-init block and perform the null-initialization there.
+ // Okay, start emitting the null-receiver block.
CGF.EmitBlock(NullBB);
- // Release consumed arguments along the null-receiver path.
+ // Release any consumed arguments we've got.
if (Method) {
CallArgList::const_iterator I = CallArgs.begin();
for (ObjCMethodDecl::param_const_iterator i = Method->param_begin(),
@@ -1596,39 +1602,60 @@
}
}
}
-
- if (result.isScalar()) {
- if (NullInitPtr)
- CGF.EmitNullInitialization(NullInitPtr, resultType);
- // Jump to the continuation block.
- CGF.EmitBlock(contBB);
- return NullInitPtr ? RValue::get(CGF.Builder.CreateLoad(NullInitPtr))
- : result;
- }
-
- if (!resultType->isAnyComplexType()) {
- assert(result.isAggregate() && "null init of non-aggregate result?");
- CGF.EmitNullInitialization(result.getAggregateAddr(), resultType);
- // Jump to the continuation block.
- CGF.EmitBlock(contBB);
+
+ // The phi code below assumes that we haven't needed any control flow yet.
+ assert(CGF.Builder.GetInsertBlock() == NullBB);
+
+ // If we've got a void return, just jump to the continuation block.
+ if (result.isScalar() && resultType->isVoidType()) {
+ // No jumps required if the message-send was noreturn.
+ if (contBB) CGF.EmitBlock(contBB);
return result;
}
- // _Complex type
- // FIXME. Now easy to handle any other scalar type whose result is returned
- // in memory due to ABI limitations.
+ // If we've got a scalar return, build a phi.
+ if (result.isScalar()) {
+ // Derive the null-initialization value.
+ llvm::Constant *null = CGF.CGM.EmitNullConstant(resultType);
+
+ // If no join is necessary, just flow out.
+ if (!contBB) return RValue::get(null);
+
+ // Otherwise, build a phi.
+ CGF.EmitBlock(contBB);
+ llvm::PHINode *phi = CGF.Builder.CreatePHI(null->getType(), 2);
+ phi->addIncoming(result.getScalarVal(), callBB);
+ phi->addIncoming(null, NullBB);
+ return RValue::get(phi);
+ }
+
+ // If we've got an aggregate return, null the buffer out.
+ // FIXME: maybe we should be doing things differently for all the
+ // cases where the ABI has us returning (1) non-agg values in
+ // memory or (2) agg values in registers.
+ if (result.isAggregate()) {
+ assert(result.isAggregate() && "null init of non-aggregate result?");
+ CGF.EmitNullInitialization(result.getAggregateAddr(), resultType);
+ if (contBB) CGF.EmitBlock(contBB);
+ return result;
+ }
+
+ // Complex types.
CGF.EmitBlock(contBB);
- CodeGenFunction::ComplexPairTy CallCV = result.getComplexVal();
- llvm::Type *MemberType = CallCV.first->getType();
- llvm::Constant *ZeroCV = llvm::Constant::getNullValue(MemberType);
- // Create phi instruction for scalar complex value.
- llvm::PHINode *PHIReal = CGF.Builder.CreatePHI(MemberType, 2);
- PHIReal->addIncoming(ZeroCV, NullBB);
- PHIReal->addIncoming(CallCV.first, callBB);
- llvm::PHINode *PHIImag = CGF.Builder.CreatePHI(MemberType, 2);
- PHIImag->addIncoming(ZeroCV, NullBB);
- PHIImag->addIncoming(CallCV.second, callBB);
- return RValue::getComplex(PHIReal, PHIImag);
+ CodeGenFunction::ComplexPairTy callResult = result.getComplexVal();
+
+ // Find the scalar type and its zero value.
+ llvm::Type *scalarTy = callResult.first->getType();
+ llvm::Constant *scalarZero = llvm::Constant::getNullValue(scalarTy);
+
+ // Build phis for both coordinates.
+ llvm::PHINode *real = CGF.Builder.CreatePHI(scalarTy, 2);
+ real->addIncoming(callResult.first, callBB);
+ real->addIncoming(scalarZero, NullBB);
+ llvm::PHINode *imag = CGF.Builder.CreatePHI(scalarTy, 2);
+ imag->addIncoming(callResult.second, callBB);
+ imag->addIncoming(scalarZero, NullBB);
+ return RValue::getComplex(real, imag);
}
};