From 992bdf1b45bdb71871975729583e193ffbd67d13 Mon Sep 17 00:00:00 2001
From: Fariborz Jahanian <fjahanian@apple.com>
Date: Mon, 27 Oct 2014 22:33:06 +0000
Subject: [PATCH] Objective-C ARC [qoi]. Issue diagnostic if __bridge casting
 to C type a collection literal. rdar://18768214

llvm-svn: 220727
---
 clang/include/clang/Basic/DiagnosticGroups.td    |  1 +
 clang/include/clang/Basic/DiagnosticSemaKinds.td |  5 +++
 clang/lib/Sema/SemaExprObjC.cpp                  | 21 +++++++++---
 clang/test/SemaObjC/arc-cfbridge-warning.m       | 41 ++++++++++++++++++++++++
 4 files changed, 63 insertions(+), 5 deletions(-)
 create mode 100644 clang/test/SemaObjC/arc-cfbridge-warning.m

diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 7a813b0..0f25a15 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -422,6 +422,7 @@ def : DiagGroup<"arc-abi">;
 def ARCUnsafeRetainedAssign : DiagGroup<"arc-unsafe-retained-assign">;
 def ARCRetainCycles : DiagGroup<"arc-retain-cycles">;
 def ARCNonPodMemAccess : DiagGroup<"arc-non-pod-memaccess">;
+def ARCBridgeCastRelease : DiagGroup<"arc-bridge-cast-release">;
 def AutomaticReferenceCounting : DiagGroup<"arc",
                                            [ARCUnsafeRetainedAssign,
                                             ARCRetainCycles,
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index fe87872..d059e87 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -4459,6 +4459,11 @@ def note_arc_retain_cycle_owner : Note<
 def warn_arc_object_memaccess : Warning<
   "%select{destination for|source of}0 this %1 call is a pointer to "
   "ownership-qualified type %2">, InGroup<ARCNonPodMemAccess>;
+  
+def warn_arc_consumed_object_released : Warning<
+  "__bridge cast of collection literal of type %1 to \"bridgeable\" C "
+  "type %0 causes early release of the collection">,
+  InGroup<ARCBridgeCastRelease>;
 
 let CategoryName = "ARC and @properties" in {
 
diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 40ab95b..5746e732 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -4075,11 +4075,22 @@ ExprResult Sema::BuildObjCBridgedCast(SourceLocation LParenLoc,
     // Okay: id -> CF
     CK = CK_BitCast;
     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_Bridge: {
+        const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(SubExpr);
+        while (implCE && implCE->getCastKind() ==  CK_BitCast)
+          implCE = dyn_cast<ImplicitCastExpr>(implCE->getSubExpr());
+        if (implCE && (implCE->getCastKind() == CK_ARCConsumeObject))
+          if (const Expr *LitExp = implCE->getSubExpr())
+            if ((isa<ObjCArrayLiteral>(LitExp) ||
+                 isa<ObjCDictionaryLiteral>(LitExp)) &&
+                T->isCARCBridgableType())
+              Diag(BridgeKeywordLoc, diag::warn_arc_consumed_object_released)
+                << T << implCE->getType();
+        // 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:        
       // Produce the object before casting it.
diff --git a/clang/test/SemaObjC/arc-cfbridge-warning.m b/clang/test/SemaObjC/arc-cfbridge-warning.m
new file mode 100644
index 0000000..142983f
--- /dev/null
+++ b/clang/test/SemaObjC/arc-cfbridge-warning.m
@@ -0,0 +1,41 @@
+// RUN: %clang_cc1 -fsyntax-only -x objective-c -fobjc-arc -verify -Wno-objc-root-class %s
+// rdar://18768214
+
+
+@class NSArray;
+typedef const struct __attribute__((objc_bridge(NSArray))) __CFArray * CFArrayRef;
+@class NSString;
+typedef const void * CFTypeRef;
+
+typedef const struct __attribute__((objc_bridge(NSString))) __CFString * CFStringRef;
+
+typedef long NSInteger;
+typedef unsigned long NSUInteger;
+
+@interface NSObject {
+    Class isa __attribute__((deprecated));
+}
++ (void)initialize;
+- (instancetype)init;
++ (instancetype)new;
++ (instancetype)alloc;
+- (void)dealloc;
+@end
+
+@interface NSArray : NSObject
+@property (readonly) NSUInteger count;
+- (id)objectAtIndex:(NSUInteger)index;
+- (instancetype)init __attribute__((objc_designated_initializer));
+- (instancetype)initWithObjects:(const id [])objects count:(NSUInteger)cnt __attribute__((objc_designated_initializer));
++ (instancetype)array;
++ (instancetype)arrayWithObject:(id)anObject;
++ (instancetype)arrayWithObjects:(const id [])objects count:(NSUInteger)cnt;
++ (instancetype)arrayWithObjects:(id)firstObj, ... __attribute__((sentinel(0,1)));
+@end
+
+static CFStringRef _s;
+
+CFArrayRef _array()
+{
+    return (__bridge CFArrayRef)@[(__bridge NSString *)_s]; // expected-warning {{__bridge cast of collection literal of type 'NSArray *' to "bridgeable" C type 'CFArrayRef' (aka 'const struct __CFArray *') causes early release of the collection}}
+}
-- 
2.7.4