In ARC, reclaim all return values of retainable type, not just those

where we have an immediate need of a retained value.

As an exception, don't do this when the call is made as the immediate
operand of a __bridge retain.  This is more in the way of a workaround
than an actual guarantee, so it's acceptable to be brittle here.

rdar://problem/9504800

llvm-svn: 134605

6 files changed, 18 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index d9e565a4404..289eaa08fb0 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2011,7 +2011,8 @@ LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
   case CK_MemberPointerToBoolean:
   case CK_AnyPointerToBlockPointerCast:
   case CK_ObjCProduceObject:
-  case CK_ObjCConsumeObject: {
+  case CK_ObjCConsumeObject:
+  case CK_ObjCReclaimReturnedObject: {
     // These casts only produce lvalues when we're binding a reference to a 
     // temporary realized from a (converted) pure rvalue. Emit the expression
     // as a value, copy it into a temporary, and return an lvalue referring to
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 99e95842eb7..93f93b77e80 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -360,6 +360,7 @@ void AggExprEmitter::VisitCastExpr(CastExpr *E) {
   case CK_IntegralComplexToFloatingComplex:
   case CK_ObjCProduceObject:
   case CK_ObjCConsumeObject:
+  case CK_ObjCReclaimReturnedObject:
     llvm_unreachable("cast kind invalid for aggregate types");
   }
 }
diff --git a/clang/lib/CodeGen/CGExprComplex.cpp b/clang/lib/CodeGen/CGExprComplex.cpp
index 95dcc0b3aea..a88f112a167 100644
--- a/clang/lib/CodeGen/CGExprComplex.cpp
+++ b/clang/lib/CodeGen/CGExprComplex.cpp
@@ -407,6 +407,7 @@ ComplexPairTy ComplexExprEmitter::EmitCast(CastExpr::CastKind CK, Expr *Op,
   case CK_IntegralComplexToBoolean:
   case CK_ObjCProduceObject:
   case CK_ObjCConsumeObject:
+  case CK_ObjCReclaimReturnedObject:
     llvm_unreachable("invalid cast kind for complex value");
 
   case CK_FloatingRealToComplex:
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index e88c28737c6..42e1450125b 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -582,6 +582,7 @@ public:
     case CK_Dynamic:
     case CK_ObjCProduceObject:
     case CK_ObjCConsumeObject:
+    case CK_ObjCReclaimReturnedObject:
       return 0;
 
     // These might need to be supported for constexpr.
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index e7ae6b5708a..84457cbbfea 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1109,6 +1109,11 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
     return CGF.EmitARCRetainScalarExpr(E);
   case CK_ObjCConsumeObject:
     return CGF.EmitObjCConsumeObject(E->getType(), Visit(E));
+  case CK_ObjCReclaimReturnedObject: {
+    llvm::Value *value = Visit(E);
+    value = CGF.EmitARCRetainAutoreleasedReturnValue(value);
+    return CGF.EmitObjCConsumeObject(E->getType(), value);
+  }
 
   case CK_FloatingRealToComplex:
   case CK_FloatingComplexCast:
diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index d8ce1f4a755..1b271ef2af8 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -2333,6 +2333,14 @@ tryEmitARCRetainScalarExpr(CodeGenFunction &CGF, const Expr *e) {
         return TryEmitResult(result, true);
       }
 
+      // For reclaims, emit the subexpression as a retained call and
+      // skip the consumption.
+      case CK_ObjCReclaimReturnedObject: {
+        llvm::Value *result = emitARCRetainCall(CGF, ce->getSubExpr());
+        if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);
+        return TryEmitResult(result, true);
+      }
+
       case CK_GetObjCProperty: {
         llvm::Value *result = emitARCRetainCall(CGF, ce);
         if (resultType) result = CGF.Builder.CreateBitCast(result, resultType);