diff --git a/clang/lib/CodeGen/CodeGenTBAA.cpp b/clang/lib/CodeGen/CodeGenTBAA.cpp index c31579e8323174a..4bcb541156bd231 100644 --- a/clang/lib/CodeGen/CodeGenTBAA.cpp +++ b/clang/lib/CodeGen/CodeGenTBAA.cpp @@ -205,14 +205,27 @@ llvm::MDNode *CodeGenTBAA::getTypeInfoHelper(const Type *Ty) { llvm::MDNode *AnyPtr = createScalarTypeNode("any pointer", getChar(), Size); if (!CodeGenOpts.PointerTBAA) return AnyPtr; - // Compute the depth of the pointer and generate a tag of the form "p - // ". + // C++ [basic.lval]p11 permits objects to accessed through an l-value of + // similar type. Two types are similar under C++ [conv.qual]p2 if the + // decomposition of the types into pointers, member pointers, and arrays has + // the same structure when ignoring cv-qualifiers at each level of the + // decomposition. Meanwhile, C makes T(*)[] and T(*)[N] compatible, which + // would really complicate any attempt to distinguish pointers to arrays by + // their bounds. It's simpler, and much easier to explain to users, to + // simply treat all pointers to arrays as pointers to their element type for + // aliasing purposes. So when creating a TBAA tag for a pointer type, we + // recursively ignore both qualifiers and array types when decomposing the + // pointee type. The only meaningful remaining structure is the number of + // pointer types we encountered along the way, so we just produce the tag + // "p ". If we do find a member pointer type, for now + // we just conservatively bail out with AnyPtr (below) rather than trying to + // create a tag that honors the similar-type rules while still + // distinguishing different kinds of member pointer. unsigned PtrDepth = 0; do { PtrDepth++; - Ty = Ty->getPointeeType().getTypePtr(); + Ty = Ty->getPointeeType()->getBaseElementTypeUnsafe(); } while (Ty->isPointerType()); - Ty = Context.getBaseElementType(QualType(Ty, 0)).getTypePtr(); assert(!isa(Ty)); // When the underlying type is a builtin type, we compute the pointee type // string recursively, which is implicitly more forgiving than the standards @@ -230,6 +243,12 @@ llvm::MDNode *CodeGenTBAA::getTypeInfoHelper(const Type *Ty) { ->getString(); TyName = Name; } else { + // Be conservative if the type isn't a RecordType. We are specifically + // required to do this for member pointers until we implement the + // similar-types rule. + if (!Ty->isRecordType()) + return AnyPtr; + // For non-builtin types use the mangled name of the canonical type. llvm::raw_svector_ostream TyOut(TyName); MangleCtx->mangleCanonicalTypeName(QualType(Ty, 0), TyOut); diff --git a/clang/test/CXX/drs/cwg158.cpp b/clang/test/CXX/drs/cwg158.cpp index 9301c790297e9d8..2a744382647773a 100644 --- a/clang/test/CXX/drs/cwg158.cpp +++ b/clang/test/CXX/drs/cwg158.cpp @@ -1,12 +1,14 @@ -// RUN: %clang_cc1 -triple x86_64-linux -std=c++98 %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck %s -// RUN: %clang_cc1 -triple x86_64-linux -std=c++11 %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck %s -// RUN: %clang_cc1 -triple x86_64-linux -std=c++14 %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck %s -// RUN: %clang_cc1 -triple x86_64-linux -std=c++1z %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck %s +// RUN: %clang_cc1 -triple x86_64-linux -std=c++98 %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck --check-prefixes=CHECK %s +// RUN: %clang_cc1 -triple x86_64-linux -std=c++11 %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck --check-prefixes=CHECK %s +// RUN: %clang_cc1 -triple x86_64-linux -std=c++14 %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck --check-prefixes=CHECK %s +// RUN: %clang_cc1 -triple x86_64-linux -std=c++1z %s -O3 -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck --check-prefixes=CHECK %s +// RUN: %clang_cc1 -triple x86_64-linux -std=c++1z %s -O3 -pointer-tbaa -disable-llvm-passes -pedantic-errors -emit-llvm -o - | FileCheck --check-prefixes=CHECK,POINTER-TBAA %s // cwg158: yes // CHECK-LABEL: define {{.*}} @_Z1f const int *f(const int * const *p, int **q) { + // CHECK: load ptr, ptr %p.addr // CHECK: load ptr, {{.*}}, !tbaa ![[INTPTR_TBAA:[^,]*]] const int *x = *p; // CHECK: store ptr null, {{.*}}, !tbaa ![[INTPTR_TBAA]] @@ -18,6 +20,7 @@ struct A {}; // CHECK-LABEL: define {{.*}} @_Z1g const int *(A::*const *g(const int *(A::* const **p)[3], int *(A::***q)[3]))[3] { + // CHECK: load ptr, ptr %p.addr // CHECK: load ptr, {{.*}}, !tbaa ![[MEMPTR_TBAA:[^,]*]] const int *(A::*const *x)[3] = *p; // CHECK: store ptr null, {{.*}}, !tbaa ![[MEMPTR_TBAA]] @@ -25,3 +28,16 @@ const int *(A::*const *g(const int *(A::* const **p)[3], int *(A::***q)[3]))[3] return x; } +// CHECK-LABEL: define {{.*}} @_Z1h +const int * h(const int * (*p)[10], int *(*q)[9]) { + // CHECK: load ptr, ptr %p.addr, align 8, !tbaa [[PTRARRAY_TBAA:!.+]] + const int * x = *p[0]; + + // CHECK: load ptr, ptr %q.addr, align 8, !tbaa [[PTRARRAY_TBAA]] + *q[0] = 0; + return x; +} + +// POINTER-TBAA: [[PTRARRAY_TBAA]] = !{[[PTRARRAY_TY:!.+]], [[PTRARRAY_TY]], i64 0} +// POINTER-TBAA: [[PTRARRAY_TY]] = !{!"p2 int", [[ANYPTR:!.+]], i64 0} +// POINTER-TBAA: [[ANYPTR]] = !{!"any pointer"