Author: rjmccall
Date: Sat Oct 1 05:32:24 2011
New Revision: 140945
URL: http://llvm.org/viewvc/llvm-project?rev=140945&view=rev
Log:
When performing an @throw in ARC, retain + autorelease
the pointer, being sure to do so before running cleanups
associated with that full-expression. rdar://10042689
Modified:
cfe/trunk/lib/CodeGen/CGObjC.cpp
cfe/trunk/lib/CodeGen/CGObjCGNU.cpp
cfe/trunk/lib/CodeGen/CGObjCMac.cpp
cfe/trunk/lib/CodeGen/CodeGenFunction.h
cfe/trunk/test/CodeGenObjC/arc-with-atthrow.m
Modified: cfe/trunk/lib/CodeGen/CGObjC.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjC.cpp?rev=140945&r1=140944&r2=140945&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjC.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjC.cpp Sat Oct 1 05:32:24 2011
@@ -2386,6 +2386,30 @@
return value;
}
+llvm::Value *CodeGenFunction::EmitObjCThrowOperand(const Expr *expr) {
+ // In ARC, retain and autorelease the expression.
+ if (getLangOptions().ObjCAutoRefCount) {
+ // Do so before running any cleanups for the full-expression.
+ // tryEmitARCRetainScalarExpr does make an effort to do things
+ // inside cleanups, but there are crazy cases like
+ // @throw A().foo;
+ // where a full retain+autorelease is required and would
+ // otherwise happen after the destructor for the temporary.
+ CodeGenFunction::RunCleanupsScope cleanups(*this);
+ if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(expr))
+ expr = ewc->getSubExpr();
+
+ return EmitARCRetainAutoreleaseScalarExpr(expr);
+ }
+
+ // Otherwise, use the normal scalar-expression emission. The
+ // exception machinery doesn't do anything special with the
+ // exception like retaining it, so there's no safety associated with
+ // only running cleanups after the throw has started, and when it
+ // matters it tends to be substantially inferior code.
+ return EmitScalarExpr(expr);
+}
+
std::pair<LValue,llvm::Value*>
CodeGenFunction::EmitARCStoreStrong(const BinaryOperator *e,
bool ignored) {
Modified: cfe/trunk/lib/CodeGen/CGObjCGNU.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjCGNU.cpp?rev=140945&r1=140944&r2=140945&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjCGNU.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjCGNU.cpp Sat Oct 1 05:32:24 2011
@@ -2277,7 +2277,7 @@
llvm::Value *ExceptionAsObject;
if (const Expr *ThrowExpr = S.getThrowExpr()) {
- llvm::Value *Exception = CGF.EmitScalarExpr(ThrowExpr);
+ llvm::Value *Exception = CGF.EmitObjCThrowOperand(ThrowExpr);
ExceptionAsObject = Exception;
} else {
assert((!CGF.ObjCEHValueStack.empty() && CGF.ObjCEHValueStack.back()) &&
Modified: cfe/trunk/lib/CodeGen/CGObjCMac.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjCMac.cpp?rev=140945&r1=140944&r2=140945&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjCMac.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjCMac.cpp Sat Oct 1 05:32:24 2011
@@ -3204,7 +3204,7 @@
llvm::Value *ExceptionAsObject;
if (const Expr *ThrowExpr = S.getThrowExpr()) {
- llvm::Value *Exception = CGF.EmitScalarExpr(ThrowExpr);
+ llvm::Value *Exception = CGF.EmitObjCThrowOperand(ThrowExpr);
ExceptionAsObject =
CGF.Builder.CreateBitCast(Exception, ObjCTypes.ObjectPtrTy);
} else {
@@ -6002,7 +6002,7 @@
void CGObjCNonFragileABIMac::EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
const ObjCAtThrowStmt &S) {
if (const Expr *ThrowExpr = S.getThrowExpr()) {
- llvm::Value *Exception = CGF.EmitScalarExpr(ThrowExpr);
+ llvm::Value *Exception = CGF.EmitObjCThrowOperand(ThrowExpr);
Exception = CGF.Builder.CreateBitCast(Exception, ObjCTypes.ObjectPtrTy);
CGF.EmitCallOrInvoke(ObjCTypes.getExceptionThrowFn(), Exception)
.setDoesNotReturn();
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=140945&r1=140944&r2=140945&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Sat Oct 1 05:32:24 2011
@@ -2141,6 +2141,8 @@
std::pair<LValue,llvm::Value*>
EmitARCStoreStrong(const BinaryOperator *e, bool ignored);
+ llvm::Value *EmitObjCThrowOperand(const Expr *expr);
+
llvm::Value *EmitObjCProduceObject(QualType T, llvm::Value *Ptr);
llvm::Value *EmitObjCConsumeObject(QualType T, llvm::Value *Ptr);
llvm::Value *EmitObjCExtendObjectLifetime(QualType T, llvm::Value *Ptr);
Modified: cfe/trunk/test/CodeGenObjC/arc-with-atthrow.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/arc-with-atthrow.m?rev=140945&r1=140944&r2=140945&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenObjC/arc-with-atthrow.m (original)
+++ cfe/trunk/test/CodeGenObjC/arc-with-atthrow.m Sat Oct 1 05:32:24 2011
@@ -1,15 +1,17 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fobjc-arc -fobjc-nonfragile-abi -fobjc-exceptions -o - %s | FileCheck %s
// pr10411
+// rdar://10042689
- at interface NSException
-+ (id)exception;
- at end
-
-void test()
-{
- @throw [NSException exception];
+id make(void);
+void test() {
+ @throw make();
}
-// CHECK: objc_retainAutoreleasedReturnValue
-// CHECK: call void @objc_release
-// CHECK: call void @objc_exception_throw
+// TODO: We should probably emit this specific pattern without the reclaim.
+
+// CHECK: define void @test()
+// CHECK: [[T0:%.*]] = call i8* @make()
+// CHECK-NEXT: [[T1:%.*]] = call i8* @objc_retainAutoreleasedReturnValue(i8* [[T0]])
+// CHECK-NEXT: [[T2:%.*]] = call i8* @objc_autorelease(i8* [[T1]])
+// CHECK-NEXT: call void @objc_exception_throw(i8* [[T2]]) noreturn
+// CHECK-NEXT: unreachable