From 9209bf11b7d171e583119c8f50a8e6cf337e5422 Mon Sep 17 00:00:00 2001 From: Akira Hatanaka Date: Fri, 11 Aug 2017 00:06:49 +0000 Subject: [PATCH] [Sema][ObjC] Fix spurious -Wcast-qual warnings. We do not meaningfully track object const-ness of Objective-C object types. Silence the -Wcast-qual warning that is issued when casting to or from Objective-C object types results in losing const qualification. rdar://problem/33807915 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@310672 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Sema/SemaCast.cpp | 9 ++++++++- test/SemaObjC/illegal-nonarc-bridged-cast.m | 17 +++++++++++++++-- 2 files changed, 23 insertions(+), 3 deletions(-) diff --git a/lib/Sema/SemaCast.cpp b/lib/Sema/SemaCast.cpp index ba2049d8a6..d603101c3f 100644 --- a/lib/Sema/SemaCast.cpp +++ b/lib/Sema/SemaCast.cpp @@ -552,7 +552,14 @@ CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType, Qualifiers SrcQuals, DestQuals; Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals); Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals); - + + // We do not meaningfully track object const-ness of Objective-C object + // types. Remove const from the source type if either the source or + // the destination is an Objective-C object type. + if (UnwrappedSrcType->isObjCObjectType() || + UnwrappedDestType->isObjCObjectType()) + SrcQuals.removeConst(); + Qualifiers RetainedSrcQuals, RetainedDestQuals; if (CheckCVR) { RetainedSrcQuals.setCVRQualifiers(SrcQuals.getCVRQualifiers()); diff --git a/test/SemaObjC/illegal-nonarc-bridged-cast.m b/test/SemaObjC/illegal-nonarc-bridged-cast.m index f3406ef983..23c7b96e37 100644 --- a/test/SemaObjC/illegal-nonarc-bridged-cast.m +++ b/test/SemaObjC/illegal-nonarc-bridged-cast.m @@ -1,8 +1,9 @@ -// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -fsyntax-only -fblocks -verify %s +// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -fsyntax-only -fblocks -Wcast-qual -verify %s // rdar://10597832 typedef const void *CFTypeRef; typedef const struct __CFString *CFStringRef; +@class NSString; @interface NSString @end @@ -18,7 +19,7 @@ NSString *CreateNSString(); void from_cf() { id obj1 = (__bridge_transfer id)CFCreateSomething(); // expected-warning {{'__bridge_transfer' casts have no effect when not using ARC}} id obj2 = (__bridge_transfer NSString*)CFCreateString(); // expected-warning {{'__bridge_transfer' casts have no effect when not using ARC}} - (__bridge int*)CFCreateSomething(); // expected-warning {{expression result unused}} + (__bridge int*)CFCreateSomething(); // expected-warning {{expression result unused}} expected-warning {{cast from 'const void *' to 'int *' drops const qualifier}} id obj3 = (__bridge id)CFGetSomething(); id obj4 = (__bridge NSString*)CFGetString(); } @@ -41,3 +42,15 @@ void to_cf_ignored(id obj) { CFTypeRef cf1 = (__bridge_retained CFTypeRef)CreateSomething(); // no-warning CFTypeRef cf3 = (__bridge CFTypeRef)CreateSomething(); // no-warning } + +// Check that clang doesn't warn about dropping const from Objective-C object +// types. +void test_wcast_qual() { + CFStringRef c; + NSString *n0 = (NSString *)c; + NSString **n1 = (NSString **)&c; + const NSString *n2; + const NSString **n3; + void *p0 = (void *)n2; + void **p1 = (void **)n3; +} -- 2.40.0