arphaman created this revision. 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 patch 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.
Repository: rL LLVM https://reviews.llvm.org/D31177 Files: lib/Sema/SemaExpr.cpp test/SemaObjCXX/arc-ptr-comparison.mm Index: test/SemaObjCXX/arc-ptr-comparison.mm =================================================================== --- /dev/null +++ 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; +} Index: lib/Sema/SemaExpr.cpp =================================================================== --- lib/Sema/SemaExpr.cpp +++ lib/Sema/SemaExpr.cpp @@ -9424,7 +9424,11 @@ // If both operands are pointers, [...] bring them to their composite // pointer type. if ((int)LHSType->isPointerType() + (int)RHSType->isPointerType() >= - (IsRelational ? 2 : 1)) { + (IsRelational || (LangOpts.ObjCAutoRefCount && + (LHSType->isObjCObjectPointerType() || + RHSType->isObjCObjectPointerType())) + ? 2 + : 1)) { if (convertPointersToCompositeType(*this, Loc, LHS, RHS)) return QualType(); else
Index: test/SemaObjCXX/arc-ptr-comparison.mm =================================================================== --- /dev/null +++ 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; +} Index: lib/Sema/SemaExpr.cpp =================================================================== --- lib/Sema/SemaExpr.cpp +++ lib/Sema/SemaExpr.cpp @@ -9424,7 +9424,11 @@ // If both operands are pointers, [...] bring them to their composite // pointer type. if ((int)LHSType->isPointerType() + (int)RHSType->isPointerType() >= - (IsRelational ? 2 : 1)) { + (IsRelational || (LangOpts.ObjCAutoRefCount && + (LHSType->isObjCObjectPointerType() || + RHSType->isObjCObjectPointerType())) + ? 2 + : 1)) { if (convertPointersToCompositeType(*this, Loc, LHS, RHS)) return QualType(); else
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