[ARC][ObjC++] Use ObjC semantic rules for comparisons between a pointer and
an ObjC object pointer
When ARC is enabled in Objective-C++, comparisons between a pointer and
Objective-C object pointer typically result in errors like this:
"invalid operands to a binary expression". This error message can be quite
confusing as it doesn't provide a solution to the problem, unlike the non-C++
diagnostic: "implicit conversion of Objective-C pointer type 'id' to C pointer
type 'void *' requires a bridged cast" (it also provides fix-its). This commit
forces comparisons between pointers and Objective-C object pointers in ARC to
use the Objective-C semantic rules to ensure that a better diagnostic is
reported.
rdar://31103857
Differential Revision: https://reviews.llvm.org/D31177
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@299080 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 70b6167e97f394781c2f17660123fe0db92650bc)
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 06d9962..8594be1 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9340,7 +9340,10 @@
// If both operands are pointers, [...] bring them to their composite
// pointer type.
if ((int)LHSType->isPointerType() + (int)RHSType->isPointerType() >=
- (IsRelational ? 2 : 1)) {
+ (IsRelational ? 2 : 1) &&
+ (!LangOpts.ObjCAutoRefCount ||
+ !(LHSType->isObjCObjectPointerType() ||
+ RHSType->isObjCObjectPointerType()))) {
if (convertPointersToCompositeType(*this, Loc, LHS, RHS))
return QualType();
else
diff --git a/test/SemaObjCXX/arc-ptr-comparison.mm b/test/SemaObjCXX/arc-ptr-comparison.mm
new file mode 100644
index 0000000..8571a81
--- /dev/null
+++ b/test/SemaObjCXX/arc-ptr-comparison.mm
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin11 -fsyntax-only -fobjc-arc -verify %s
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-apple-darwin11 -fsyntax-only -verify -DNOARC %s
+#ifdef NOARC
+// expected-no-diagnostics
+#endif
+
+int testObjCComparisonRules(void *v, id x, id y) {
+ return v == x;
+#ifndef NOARC
+// expected-error@-2 {{implicit conversion of Objective-C pointer type 'id' to C pointer type 'void *' requires a bridged cast}}
+// expected-note@-3 {{use __bridge to convert directly (no change in ownership)}}
+// expected-note@-4 {{use __bridge_retained to make an ARC object available as a +1 'void *'}}
+#endif
+ return v >= x;
+#ifndef NOARC
+// expected-error@-2 {{implicit conversion of Objective-C pointer type 'id' to C pointer type 'void *' requires a bridged cast}}
+// expected-note@-3 {{use __bridge to convert directly (no change in ownership)}}
+// expected-note@-4 {{use __bridge_retained to make an ARC object available as a +1 'void *'}}
+#endif
+ return v == (id)(void *)0; // OK
+ return v == nullptr; // OK
+ return v == (void *)0;
+ return x == y;
+}
