[Sema][ObjC] Allow conversions between pointers to ObjC pointers and

pointers to structs

clang was just being conservative and trying to prevent users from
messing up the qualifier on the inner pointer type. Lifting this
restriction enables using some of the libc++ templates with ObjC pointer
arguments, which clang currently rejects.

rdar://79018677

Differential Revision: https://reviews.llvm.org/D107021

diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 9e46801..102edb0 100644 (file)
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -4450,9 +4450,14 @@ Sema::CheckObjCConversion(SourceRange castRange, QualType castType,
   // Allow casts between pointers to lifetime types (e.g., __strong id*)
   // and pointers to void (e.g., cv void *). Casting from void* to lifetime*
   // must be explicit.
-  if (exprACTC == ACTC_indirectRetainable && castACTC == ACTC_voidPtr)
+  // Allow conversions between pointers to lifetime types and coreFoundation
+  // pointers too, but only when the conversions are explicit.
+  if (exprACTC == ACTC_indirectRetainable &&
+      (castACTC == ACTC_voidPtr ||
+       (castACTC == ACTC_coreFoundation && isCast(CCK))))
     return ACR_okay;
-  if (castACTC == ACTC_indirectRetainable && exprACTC == ACTC_voidPtr &&
+  if (castACTC == ACTC_indirectRetainable &&
+      (exprACTC == ACTC_voidPtr || exprACTC == ACTC_coreFoundation) &&
       isCast(CCK))
     return ACR_okay;
 

diff --git a/clang/test/SemaObjC/arc-type-conversion.m b/clang/test/SemaObjC/arc-type-conversion.m
index 5cf2cf4..a349d00 100644 (file)
--- a/clang/test/SemaObjC/arc-type-conversion.m
+++ b/clang/test/SemaObjC/arc-type-conversion.m
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -fobjc-runtime-has-weak -verify -fblocks %s
+// RUN: %clang_cc1 -fsyntax-only -fobjc-arc -fobjc-runtime-has-weak -verify -fblocks -Wno-incompatible-pointer-types %s
 
 typedef const void * CFTypeRef;
 CFTypeRef CFBridgingRetain(id X);
@@ -96,3 +96,14 @@ void conversion_in_conditional(id a, void* b) {
   id c = 1 ? a : b; // expected-error {{operands to conditional of types 'id' and 'void *' are incompatible in ARC mode}}
   id d = 1 ? b : a; // expected-error {{operands to conditional of types 'void *' and 'id' are incompatible in ARC mode}}
 }
+
+void conversion_pointer_to_id(__strong id *x) {
+  struct S {
+    int a[2];
+  } s, *p;
+
+  x = (__strong id *)&s;
+  x = &s; // expected-error {{implicit conversion of a non-Objective-C pointer type 'struct S *' to '__strong id *' is disallowed with ARC}}
+  p = (struct S *)x;
+  p = x; // expected-error {{implicit conversion of an indirect pointer to an Objective-C pointer to 'struct S *' is disallowed with ARC}}
+}