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
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134605 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
index c177363..fe80a43 100644
--- a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
+++ b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
@@ -116,11 +116,16 @@
return true;
}
- if (ParenExpr *parenE = dyn_cast_or_null<ParenExpr>(StmtMap->getParent(E)))
+ Stmt *parent = StmtMap->getParent(E);
+
+ if (ImplicitCastExpr *castE = dyn_cast_or_null<ImplicitCastExpr>(parent))
+ return tryRemoving(castE);
+
+ if (ParenExpr *parenE = dyn_cast_or_null<ParenExpr>(parent))
return tryRemoving(parenE);
if (BinaryOperator *
- bopE = dyn_cast_or_null<BinaryOperator>(StmtMap->getParent(E))) {
+ bopE = dyn_cast_or_null<BinaryOperator>(parent)) {
if (bopE->getOpcode() == BO_Comma && bopE->getLHS() == E &&
isRemovable(bopE)) {
Pass.TA.replace(bopE->getSourceRange(), bopE->getRHS()->getSourceRange());
diff --git a/lib/ARCMigrate/TransformActions.cpp b/lib/ARCMigrate/TransformActions.cpp
index 45a3d47..2ae9798 100644
--- a/lib/ARCMigrate/TransformActions.cpp
+++ b/lib/ARCMigrate/TransformActions.cpp
@@ -313,7 +313,7 @@
assert(IsInTransaction && "Actions only allowed during a transaction");
ActionData data;
data.Kind = Act_RemoveStmt;
- data.S = S;
+ data.S = S->IgnoreImplicit(); // important for uniquing
CachedActions.push_back(data);
}
diff --git a/lib/ARCMigrate/Transforms.cpp b/lib/ARCMigrate/Transforms.cpp
index 1a98833..80c52d7 100644
--- a/lib/ARCMigrate/Transforms.cpp
+++ b/lib/ARCMigrate/Transforms.cpp
@@ -180,12 +180,9 @@
void mark(Stmt *S) {
if (!S) return;
- if (LabelStmt *Label = dyn_cast<LabelStmt>(S))
- return mark(Label->getSubStmt());
- if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(S))
- return mark(CE->getSubExpr());
- if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(S))
- return mark(EWC->getSubExpr());
+ while (LabelStmt *Label = dyn_cast<LabelStmt>(S))
+ S = Label->getSubStmt();
+ S = S->IgnoreImplicit();
if (Expr *E = dyn_cast<Expr>(S))
Removables.insert(E);
}
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 3002e30..5d8789f 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1102,6 +1102,8 @@
return "ObjCConsumeObject";
case CK_ObjCProduceObject:
return "ObjCProduceObject";
+ case CK_ObjCReclaimReturnedObject:
+ return "ObjCReclaimReturnedObject";
}
llvm_unreachable("Unhandled cast kind!");
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index cc8c501..9943222 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -1819,6 +1819,7 @@
case CK_UserDefinedConversion:
case CK_ObjCProduceObject:
case CK_ObjCConsumeObject:
+ case CK_ObjCReclaimReturnedObject:
return false;
case CK_LValueToRValue:
@@ -2325,6 +2326,7 @@
case CK_IntegralComplexToBoolean:
case CK_ObjCProduceObject:
case CK_ObjCConsumeObject:
+ case CK_ObjCReclaimReturnedObject:
llvm_unreachable("invalid cast kind for complex value");
case CK_LValueToRValue:
diff --git a/lib/AST/Stmt.cpp b/lib/AST/Stmt.cpp
index e293f32..fd6f21d 100644
--- a/lib/AST/Stmt.cpp
+++ b/lib/AST/Stmt.cpp
@@ -85,6 +85,18 @@
return StatSwitch;
}
+Stmt *Stmt::IgnoreImplicit() {
+ Stmt *s = this;
+
+ if (ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(s))
+ s = ewc->getSubExpr();
+
+ while (ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(s))
+ s = ice->getSubExpr();
+
+ return s;
+}
+
namespace {
struct good {};
struct bad {};
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index d9e565a..289eaa0 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -2011,7 +2011,8 @@
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/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 99e9584..93f93b7 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -360,6 +360,7 @@
case CK_IntegralComplexToFloatingComplex:
case CK_ObjCProduceObject:
case CK_ObjCConsumeObject:
+ case CK_ObjCReclaimReturnedObject:
llvm_unreachable("cast kind invalid for aggregate types");
}
}
diff --git a/lib/CodeGen/CGExprComplex.cpp b/lib/CodeGen/CGExprComplex.cpp
index 95dcc0b..a88f112 100644
--- a/lib/CodeGen/CGExprComplex.cpp
+++ b/lib/CodeGen/CGExprComplex.cpp
@@ -407,6 +407,7 @@
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/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index e88c287..42e1450 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -582,6 +582,7 @@
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/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index e7ae6b5..84457cb 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -1109,6 +1109,11 @@
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/lib/CodeGen/CGObjC.cpp b/lib/CodeGen/CGObjC.cpp
index d8ce1f4..1b271ef 100644
--- a/lib/CodeGen/CGObjC.cpp
+++ b/lib/CodeGen/CGObjC.cpp
@@ -2333,6 +2333,14 @@
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);
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 35b6e9a..8bad032 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -3543,6 +3543,7 @@
case CK_BitCast:
case CK_LValueBitCast:
case CK_LValueToRValue:
+ case CK_ObjCReclaimReturnedObject:
e = cast->getSubExpr();
continue;
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 6ae48dd..4c096fe 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -4039,13 +4039,12 @@
ReturnsRetained = (D && D->hasAttr<NSReturnsRetainedAttr>());
}
- if (ReturnsRetained) {
- ExprNeedsCleanups = true;
- E = ImplicitCastExpr::Create(Context, E->getType(),
- CK_ObjCConsumeObject, E, 0,
- VK_RValue);
- }
- return Owned(E);
+ ExprNeedsCleanups = true;
+
+ CastKind ck = (ReturnsRetained ? CK_ObjCConsumeObject
+ : CK_ObjCReclaimReturnedObject);
+ return Owned(ImplicitCastExpr::Create(Context, E->getType(), ck, E, 0,
+ VK_RValue));
}
if (!getLangOptions().CPlusPlus)
diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index 17a7401..fa51098 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -1771,6 +1771,20 @@
<< castRange << castExpr->getSourceRange();
}
+/// Look for an ObjCReclaimReturnedObject cast and destroy it.
+static Expr *maybeUndoReclaimObject(Expr *e) {
+ // For now, we just undo operands that are *immediately* reclaim
+ // expressions, which prevents the vast majority of potential
+ // problems here. To catch them all, we'd need to rebuild arbitrary
+ // value-propagating subexpressions --- we can't reliably rebuild
+ // in-place because of expression sharing.
+ if (ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(e))
+ if (ice->getCastKind() == CK_ObjCReclaimReturnedObject)
+ return ice->getSubExpr();
+
+ return e;
+}
+
ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
ObjCBridgeCastKind Kind,
SourceLocation BridgeKeywordLoc,
@@ -1815,6 +1829,9 @@
// Okay: id -> CF
switch (Kind) {
case OBC_Bridge:
+ // Reclaiming a value that's going to be __bridge-casted to CF
+ // is very dangerous, so we don't do it.
+ SubExpr = maybeUndoReclaimObject(SubExpr);
break;
case OBC_BridgeRetained:
diff --git a/lib/StaticAnalyzer/Core/ExprEngine.cpp b/lib/StaticAnalyzer/Core/ExprEngine.cpp
index 4aa5e35..fbaa849 100644
--- a/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -2194,7 +2194,8 @@
// The analyzer doesn't do anything special with these casts,
// since it understands retain/release semantics already.
case CK_ObjCProduceObject:
- case CK_ObjCConsumeObject: // Fall-through.
+ case CK_ObjCConsumeObject:
+ case CK_ObjCReclaimReturnedObject: // Fall-through.
// True no-ops.
case CK_NoOp:
case CK_FunctionToPointerDecay: {