Should this go into 5.0 ? On Tue, Jul 25, 2017 at 4:33 PM, David Majnemer via cfe-commits < cfe-commits@lists.llvm.org> wrote:
> Author: majnemer > Date: Tue Jul 25 16:33:58 2017 > New Revision: 309058 > > URL: http://llvm.org/viewvc/llvm-project?rev=309058&view=rev > Log: > [CodeGen] Correctly model std::byte's aliasing properties > > std::byte, when defined as an enum, needs to be given special treatment > with regards to its aliasing properties. An array of std::byte is > allowed to be used as storage for other types. > > This fixes PR33916. > > Differential Revision: https://reviews.llvm.org/D35824 > > Added: > cfe/trunk/test/CodeGenCXX/std-byte.cpp > Modified: > cfe/trunk/include/clang/AST/Type.h > cfe/trunk/lib/AST/Type.cpp > cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp > > Modified: cfe/trunk/include/clang/AST/Type.h > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/ > clang/AST/Type.h?rev=309058&r1=309057&r2=309058&view=diff > ============================================================ > ================== > --- cfe/trunk/include/clang/AST/Type.h (original) > +++ cfe/trunk/include/clang/AST/Type.h Tue Jul 25 16:33:58 2017 > @@ -1752,6 +1752,7 @@ public: > bool isTemplateTypeParmType() const; // C++ template type > parameter > bool isNullPtrType() const; // C++11 std::nullptr_t > bool isAlignValT() const; // C++17 std::align_val_t > + bool isStdByteType() const; // C++17 std::byte > bool isAtomicType() const; // C11 _Atomic() > > #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \ > > Modified: cfe/trunk/lib/AST/Type.cpp > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ > Type.cpp?rev=309058&r1=309057&r2=309058&view=diff > ============================================================ > ================== > --- cfe/trunk/lib/AST/Type.cpp (original) > +++ cfe/trunk/lib/AST/Type.cpp Tue Jul 25 16:33:58 2017 > @@ -2313,6 +2313,15 @@ bool Type::isAlignValT() const { > return false; > } > > +bool Type::isStdByteType() const { > + if (auto *ET = getAs<EnumType>()) { > + auto *II = ET->getDecl()->getIdentifier(); > + if (II && II->isStr("byte") && ET->getDecl()->isInStdNamespace()) > + return true; > + } > + return false; > +} > + > bool Type::isPromotableIntegerType() const { > if (const BuiltinType *BT = getAs<BuiltinType>()) > switch (BT->getKind()) { > > Modified: cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ > CodeGenTBAA.cpp?rev=309058&r1=309057&r2=309058&view=diff > ============================================================ > ================== > --- cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp (original) > +++ cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp Tue Jul 25 16:33:58 2017 > @@ -139,6 +139,12 @@ CodeGenTBAA::getTBAAInfo(QualType QTy) { > } > } > > + // C++1z [basic.lval]p10: "If a program attempts to access the stored > value of > + // an object through a glvalue of other than one of the following types > the > + // behavior is undefined: [...] a char, unsigned char, or std::byte > type." > + if (Ty->isStdByteType()) > + return MetadataCache[Ty] = getChar(); > + > // Handle pointers. > // TODO: Implement C++'s type "similarity" and consider dis-"similar" > // pointers distinct. > > Added: cfe/trunk/test/CodeGenCXX/std-byte.cpp > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/ > CodeGenCXX/std-byte.cpp?rev=309058&view=auto > ============================================================ > ================== > --- cfe/trunk/test/CodeGenCXX/std-byte.cpp (added) > +++ cfe/trunk/test/CodeGenCXX/std-byte.cpp Tue Jul 25 16:33:58 2017 > @@ -0,0 +1,41 @@ > +// RUN: %clang_cc1 -std=c++1z -Werror -triple i386-unknown-unknown > -emit-llvm -O1 -disable-llvm-passes -o - %s | FileCheck %s > + > +// std::byte should be considered equivalent to char for aliasing. > + > +namespace std { > +enum byte : unsigned char {}; > +} > + > +// CHECK-LABEL: define void @test0( > +extern "C" void test0(std::byte *sb, int *i) { > + // CHECK: store i8 0, i8* %{{.*}} !tbaa [[TAG_CHAR:!.*]] > + *sb = std::byte{0}; > + > + // CHECK: store i32 1, i32* %{{.*}} !tbaa [[TAG_INT:!.*]] > + *i = 1; > +} > + > +enum byte : unsigned char {}; > +namespace my { > +enum byte : unsigned char {}; > +namespace std { > +enum byte : unsigned char {}; > +} // namespace std > +} // namespace my > + > +// Make sure we don't get confused with other enums named 'byte'. > + > +// CHECK-LABEL: define void @test1( > +extern "C" void test1(::byte *b, ::my::byte *mb, ::my::std::byte *msb) { > + *b = ::byte{0}; > + *mb = ::my::byte{0}; > + *msb = ::my::std::byte{0}; > + // CHECK-NOT: store i8 0, i8* %{{.*}} !tbaa [[TAG_CHAR]] > +} > + > +// CHECK: !"any pointer", [[TYPE_CHAR:!.*]], > +// CHECK: [[TYPE_CHAR]] = !{!"omnipotent char", [[TAG_CXX_TBAA:!.*]], > +// CHECK: [[TAG_CXX_TBAA]] = !{!"Simple C++ TBAA"} > +// CHECK: [[TAG_CHAR]] = !{[[TYPE_CHAR:!.*]], [[TYPE_CHAR]], i64 0} > +// CHECK: [[TAG_INT]] = !{[[TYPE_INT:!.*]], [[TYPE_INT]], i64 0} > +// CHECK: [[TYPE_INT]] = !{!"int", [[TYPE_CHAR]] > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >
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