arc migrator: Do not attempt to migrate to bridge casts which

cancel out each other. Leave it alone so users can take a look
(unmigrated code forces error diagnostic). // rdar://10521744

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149435 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/ARCMigrate/TransUnbridgedCasts.cpp b/lib/ARCMigrate/TransUnbridgedCasts.cpp
index 3bfa15c6e0ae1726809304a65e32ef4f72c23b6a..5650824c964167fea0531d250157acfc36527a1b 100644 (file)
--- a/lib/ARCMigrate/TransUnbridgedCasts.cpp
+++ b/lib/ARCMigrate/TransUnbridgedCasts.cpp
@@ -128,6 +128,21 @@ private:
           if (fname.endswith("Retain") ||
               fname.find("Create") != StringRef::npos ||
               fname.find("Copy") != StringRef::npos) {
+            // Do not migrate to couple of bridge transfer casts which
+            // cancel each other out. Leave it unchanged so error gets user
+            // attention instead.
+            if (FD->getName() == "CFRetain" && 
+                FD->getNumParams() == 1 &&
+                FD->getParent()->isTranslationUnit() &&
+                FD->getLinkage() == ExternalLinkage) {
+              Expr *Arg = callE->getArg(0);
+              if (const CastExpr *ICE = dyn_cast<CastExpr>(Arg)) {
+                const Expr *sub = ICE->getSubExpr();
+                QualType T = sub->getType();
+                if (T->isObjCObjectPointerType())
+                  return;
+              }
+            }
             castToObjCObject(E, /*retained=*/true);
             return;
           }

diff --git a/test/ARCMT/no-canceling-bridge-to-bridge-cast.m b/test/ARCMT/no-canceling-bridge-to-bridge-cast.m
new file mode 100644 (file)
index 0000000..e94e657
--- /dev/null
+++ b/test/ARCMT/no-canceling-bridge-to-bridge-cast.m
@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -arcmt-check -triple x86_64-apple-darwin10 -fsyntax-only -x objective-c -verify %s 
+// DISABLE: mingw32
+// rdar://10387088
+typedef const void * CFTypeRef;
+
+extern 
+CFTypeRef CFRetain(CFTypeRef cf);
+
+@interface INTF
+{
+  void *cf_format;
+  id objc_format;
+}
+@end
+
+@interface NSString
++ (id)stringWithFormat:(NSString *)format;
+@end
+
+@implementation INTF
+- (void) Meth {
+  NSString *result;
+
+  result = (id) CFRetain([NSString stringWithFormat:@"PBXLoopMode"]); // expected-error {{cast of C pointer type 'CFTypeRef' (aka 'const void *') to Objective-C pointer type 'id' requires a bridged cast}} \
+                                                                     // expected-note {{use __bridge to convert directly (no change in ownership)}} \
+                                                                     // expected-note {{use __bridge_transfer to transfer ownership of a +1 'CFTypeRef' (aka 'const void *') into ARC}}
+
+  result = (id) CFRetain((id)((objc_format))); // expected-error {{cast of C pointer type 'CFTypeRef' (aka 'const void *') to Objective-C pointer type 'id' requires a bridged cast}} \
+                                              // expected-note {{use __bridge to convert directly (no change in ownership)}} \
+                                              // expected-note {{use __bridge_transfer to transfer ownership of a +1 'CFTypeRef' (aka 'const void *') into ARC}}
+
+  result = (id) CFRetain((id)((cf_format))); // expected-error {{cast of C pointer type 'CFTypeRef' (aka 'const void *') to Objective-C pointer type 'id' requires a bridged cast}} \
+                                            // expected-note {{use __bridge to convert directly (no change in ownership)}} \
+                                             // expected-note {{use __bridge_transfer to transfer ownership of a +1 'CFTypeRef' (aka 'const void *') into ARC}}
+
+  result = (id) CFRetain((CFTypeRef)((objc_format))); // expected-error {{cast of C pointer type 'CFTypeRef' (aka 'const void *') to Objective-C pointer type 'id' requires a bridged cast}} \
+                                                     // expected-note {{use __bridge to convert directly (no change in ownership)}} \
+                                                      // expected-note {{use __bridge_transfer to transfer ownership of a +1 'CFTypeRef' (aka 'const void *') into ARC}}
+
+  result = (id) CFRetain(cf_format); // OK
+}
+@end
+