r194647 - Suppress -Wunused-variable when initializer uses bridge casts for memory management.
Ted Kremenek
kremenek at apple.com
Wed Nov 13 17:42:17 PST 2013
Author: kremenek
Date: Wed Nov 13 19:42:17 2013
New Revision: 194647
URL: http://llvm.org/viewvc/llvm-project?rev=194647&view=rev
Log:
Suppress -Wunused-variable when initializer uses bridge casts for memory management.
Fixes <rdar://problem/15432770>.
Modified:
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/test/SemaObjC/arc-bridged-cast.m
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=194647&r1=194646&r2=194647&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Nov 13 19:42:17 2013
@@ -1313,6 +1313,28 @@ static bool ShouldDiagnoseUnusedDecl(con
}
}
+ // Under ARC, bridged casts can have side-effects on memory
+ // management semantics. Some users assign a bridged
+ // value to a temporary to adjust reference counts.
+ const Expr *Init = VD->getInit();
+ if (Init) {
+ if (const ExprWithCleanups *EC = dyn_cast<ExprWithCleanups>(Init))
+ Init = EC->getSubExpr();
+ Init = Init->IgnoreParens();
+ if (const ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(Init)) {
+ switch (IC->getCastKind()) {
+ case CK_ARCProduceObject:
+ case CK_ARCConsumeObject:
+ case CK_ARCReclaimReturnedObject:
+ case CK_ARCExtendBlockObject:
+ case CK_CopyAndAutoreleaseBlockObject:
+ return false;
+ default:
+ break;
+ }
+ }
+ }
+
// TODO: __attribute__((unused)) templates?
}
Modified: cfe/trunk/test/SemaObjC/arc-bridged-cast.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/arc-bridged-cast.m?rev=194647&r1=194646&r2=194647&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/arc-bridged-cast.m (original)
+++ cfe/trunk/test/SemaObjC/arc-bridged-cast.m Wed Nov 13 19:42:17 2013
@@ -62,3 +62,15 @@ CFTypeRef fixitsWithSpace(id obj) {
// CHECK: fix-it:"{{.*}}":{59:9-59:9}:"(__bridge CFTypeRef)"
// CHECK: fix-it:"{{.*}}":{59:9-59:9}:" CFBridgingRetain"
}
+
+// <rdar://problem/15432770>
+// Suppressed -Wunused-variable when the initializer is a bridge cast.
+#pragma clang diagnostic push
+#pragma clang diagnostic warning "-Wunused-variable"
+void rdar15432770() {
+ void (^block1)() = ^ { };
+ void *ptr = (__bridge_retained void *)(block1);
+ void (^block2)() = (__bridge_transfer void(^)())ptr; // no-warning
+ int x = 1; // expected-warning {{unused variable}}
+}
+#pragma clang diagnostic pop
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