[PATCH] D99661: [SemaObjC] Fix a -Wbridge-cast false-positive

[Erik Pilkington via Phabricator via cfe-commits]

erik.pilkington updated this revision to Diff 334801.
erik.pilkington added a comment.

In D99661#2662601 <https://reviews.llvm.org/D99661#2662601>, @ahatanak wrote:

> Should we try to restore the behavior prior to 
> https://reviews.llvm.org/rG09abecef7bbfda18d34f046954eaa4d491062839 as much 
> as we can? Or that's not important?

Sure, the new patch starts iterating through the redeclarations starting at the 
most recent declaration, which should mimic the old behaviour. I'm not sure it 
matters, having multiple `objc_bridge` attributes has never actually worked 
(`objc_bridge` attributes appearing earlier get "shadowed" by the most recent 
one), i.e. in your testcase `CFStringGetLength((__bridge CFStringRef)(NSError 
*)0);` has always lead to a -Wbridge-cast diagnostic.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99661/new/

https://reviews.llvm.org/D99661

Files:
  clang/lib/Sema/SemaExprObjC.cpp
  clang/test/SemaObjCXX/bridge-cast-redecl.mm


Index: clang/test/SemaObjCXX/bridge-cast-redecl.mm
===================================================================
--- /dev/null
+++ clang/test/SemaObjCXX/bridge-cast-redecl.mm
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -std=gnu++17 -verify %s
+
+// expected-no-diagnostics
+
+typedef const struct __CFString * CFStringRef;
+
+extern "C" {
+  typedef const struct __attribute__((objc_bridge(NSString))) __CFString * 
CFStringRef;
+  typedef struct __attribute__((objc_bridge_mutable(NSMutableString))) 
__CFString * CFMutableStringRef;
+}
+
+@interface NSString @end
+@interface NSMutableString : NSString @end
+
+void CFStringGetLength(CFStringRef theString);
+
+int main() {
+  CFStringGetLength((__bridge CFStringRef)(NSString *)0);
+}
Index: clang/lib/Sema/SemaExprObjC.cpp
===================================================================
--- clang/lib/Sema/SemaExprObjC.cpp
+++ clang/lib/Sema/SemaExprObjC.cpp
@@ -3847,9 +3847,12 @@
   QualType QT = TDNDecl->getUnderlyingType();
   if (QT->isPointerType()) {
     QT = QT->getPointeeType();
-    if (const RecordType *RT = QT->getAs<RecordType>())
-      if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
-        return RD->getAttr<T>();
+    if (const RecordType *RT = QT->getAs<RecordType>()) {
+      for (auto *Redecl : RT->getDecl()->getMostRecentDecl()->redecls()) {
+        if (auto *attr = Redecl->getAttr<T>())
+          return attr;
+      }
+    }
   }
   return nullptr;
 }



Index: clang/test/SemaObjCXX/bridge-cast-redecl.mm
===================================================================
--- /dev/null
+++ clang/test/SemaObjCXX/bridge-cast-redecl.mm
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -std=gnu++17 -verify %s
+
+// expected-no-diagnostics
+
+typedef const struct __CFString * CFStringRef;
+
+extern "C" {
+  typedef const struct __attribute__((objc_bridge(NSString))) __CFString * CFStringRef;
+  typedef struct __attribute__((objc_bridge_mutable(NSMutableString))) __CFString * CFMutableStringRef;
+}
+
+@interface NSString @end
+@interface NSMutableString : NSString @end
+
+void CFStringGetLength(CFStringRef theString);
+
+int main() {
+  CFStringGetLength((__bridge CFStringRef)(NSString *)0);
+}
Index: clang/lib/Sema/SemaExprObjC.cpp
===================================================================
--- clang/lib/Sema/SemaExprObjC.cpp
+++ clang/lib/Sema/SemaExprObjC.cpp
@@ -3847,9 +3847,12 @@
   QualType QT = TDNDecl->getUnderlyingType();
   if (QT->isPointerType()) {
     QT = QT->getPointeeType();
-    if (const RecordType *RT = QT->getAs<RecordType>())
-      if (RecordDecl *RD = RT->getDecl()->getMostRecentDecl())
-        return RD->getAttr<T>();
+    if (const RecordType *RT = QT->getAs<RecordType>()) {
+      for (auto *Redecl : RT->getDecl()->getMostRecentDecl()->redecls()) {
+        if (auto *attr = Redecl->getAttr<T>())
+          return attr;
+      }
+    }
   }
   return nullptr;
 }

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