Merge pull request #8375 from fhahn/tbaa-struct-union

Pick fixes for Unions & tbaa.struct

Author: fhahn

clang/lib/CodeGen/CodeGenTBAA.cpp

@@ -283,6 +283,14 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset,
   /* Things not handled yet include: C++ base classes, bitfields, */
 
   if (const RecordType *TTy = QTy->getAs<RecordType>()) {
+    if (TTy->isUnionType()) {
+      uint64_t Size = Context.getTypeSizeInChars(QTy).getQuantity();
+      llvm::MDNode *TBAAType = getChar();
+      llvm::MDNode *TBAATag = getAccessTagInfo(TBAAAccessInfo(TBAAType, Size));
+      Fields.push_back(
+          llvm::MDBuilder::TBAAStructField(BaseOffset, Size, TBAATag));
+      return true;
+    }
     const RecordDecl *RD = TTy->getDecl()->getDefinition();
     if (RD->hasFlexibleArrayMember())
       return false;
@@ -340,6 +348,9 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset,
 
 llvm::MDNode *
 CodeGenTBAA::getTBAAStructInfo(QualType QTy) {
+  if (CodeGenOpts.OptimizationLevel == 0 || CodeGenOpts.RelaxedAliasing)
+    return nullptr;
+
   const Type *Ty = Context.getCanonicalType(QTy).getTypePtr();
 
   if (llvm::MDNode *N = StructMetadataCache[Ty])

clang/test/CodeGen/tbaa-struct-relaxed-aliasing-with-tsan.cpp

@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -emit-llvm -o - -O1 -relaxed-aliasing -fsanitize=thread -disable-llvm-optzns %s | \
+// RUN:     FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -new-struct-path-tbaa \
+// RUN:     -emit-llvm -o - -O1 -relaxed-aliasing -fsanitize=thread -disable-llvm-optzns %s | \
+// RUN:     FileCheck %s
+//
+// Check that we do not create tbaa for instructions generated for copies.
+
+// CHECK-NOT: !tbaa
+
+struct A {
+  short s;
+  int i;
+  char c;
+  int j;
+};
+
+void copyStruct(A *a1, A *a2) {
+  *a1 = *a2;
+}
+
+void copyInt(int *a, int *b) {
+  *a = *b;
+}

clang/test/CodeGen/tbaa-struct.cpp

@@ -151,6 +151,38 @@ void copy10(NamedBitfields3 *a1, NamedBitfields3 *a2) {
   *a1 = *a2;
 }
 
+union U2 {
+  double d;
+  float f;
+};
+
+struct UnionMember1 {
+  U2 u;
+  int p;
+};
+
+void copy11(UnionMember1 *a1, UnionMember1 *a2) {
+// CHECK-LABEL: _Z6copy11P12UnionMember1S0_
+// CHECK:   tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 8 dereferenceable(16) %a1, ptr noundef nonnull align 8 dereferenceable(16) %a2, i64 16, i1 false),
+// CHECK-OLD-SAME: !tbaa.struct [[TS9:!.*]]
+// CHECK-NEW-SAME: !tbaa [[TAG_UnionMember1:!.+]], !tbaa.struct
+  *a1 = *a2;
+}
+
+struct UnionMember2 {
+  int p;
+  U2 u;
+};
+
+void copy12(UnionMember2 *a1, UnionMember2 *a2) {
+// CHECK-LABEL: _Z6copy12P12UnionMember2S0_
+// CHECK:   tail call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 8 dereferenceable(16) %a1, ptr noundef nonnull align 8 dereferenceable(16) %a2, i64 16, i1 false),
+// CHECK-OLD-SAME: !tbaa.struct [[TS10:!.*]]
+// CHECK-NEW-SAME: !tbaa [[TAG_UnionMember2:!.+]], !tbaa.struct
+
+  *a1 = *a2;
+}
+
 // CHECK-OLD: [[TS]] = !{i64 0, i64 2, !{{.*}}, i64 4, i64 4, !{{.*}}, i64 8, i64 1, !{{.*}}, i64 12, i64 4, !{{.*}}}
 // CHECK-OLD: [[CHAR:!.*]] = !{!"omnipotent char", !{{.*}}}
 // CHECK-OLD: [[TAG_INT:!.*]] = !{[[INT:!.*]], [[INT]], i64 0}
@@ -159,14 +191,16 @@ void copy10(NamedBitfields3 *a1, NamedBitfields3 *a2) {
 // (offset, size) = (0,1) char; (4,2) short; (8,4) int; (12,1) char; (16,4) int; (20,4) int
 // CHECK-OLD: [[TS2]] = !{i64 0, i64 1, !{{.*}}, i64 4, i64 2, !{{.*}}, i64 8, i64 4, !{{.*}}, i64 12, i64 1, !{{.*}}, i64 16, i64 4, {{.*}}, i64 20, i64 4, {{.*}}}
 // (offset, size) = (0,8) char; (0,2) char; (4,8) char
-// CHECK-OLD: [[TS3]] = !{i64 0, i64 8, !{{.*}}, i64 0, i64 2, !{{.*}}, i64 4, i64 8, !{{.*}}}
+// CHECK-OLD: [[TS3]] = !{i64 0, i64 12, [[TAG_CHAR]]}
 // CHECK-OLD: [[TS4]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]]}
 // CHECK-OLD: [[TS5]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 4, i64 1, [[TAG_CHAR]], i64 5, i64 1, [[TAG_CHAR]]}
 // CHECK-OLD: [[TS6]] = !{i64 0, i64 2, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE:!.+]]}
 // CHECK-OLD: [[TAG_DOUBLE]] = !{[[DOUBLE:!.+]], [[DOUBLE]], i64 0}
 // CHECK-OLD  [[DOUBLE]] = !{!"double", [[CHAR]], i64 0}
 // CHECK-OLD: [[TS7]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]], i64 3, i64 1, [[TAG_CHAR]], i64 4, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE]], i64 16, i64 1, [[TAG_CHAR]]}
 // CHECK-OLD: [[TS8]] = !{i64 0, i64 4, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE]]}
+// CHECK-OLD: [[TS9]] = !{i64 0, i64 8, [[TAG_CHAR]], i64 8, i64 4, [[TAG_INT]]}
+// CHECK-OLD: [[TS10]] = !{i64 0, i64 4, [[TAG_INT]], i64 8, i64 8, [[TAG_CHAR]]}
 
 // CHECK-NEW-DAG: [[TYPE_char:!.*]] = !{{{.*}}, i64 1, !"omnipotent char"}
 // CHECK-NEW-DAG: [[TAG_char]] = !{[[TYPE_char]], [[TYPE_char]], i64 0, i64 0}
@@ -188,3 +222,7 @@ void copy10(NamedBitfields3 *a1, NamedBitfields3 *a2) {
 // CHECK-NEW-DAG: [[TYPE_NamedBitfields2]] = !{[[TYPE_char]], i64 24, !"_ZTS15NamedBitfields2", [[TYPE_char]], i64 0, i64 1, [[TYPE_char]], i64 1, i64 1, [[TYPE_char]], i64 2, i64 1, [[TYPE_int]], i64 3, i64 4, [[TYPE_int]], i64 3, i64 4, [[TYPE_char]], i64 4, i64 1, [[TYPE_double]], i64 8, i64 8, [[TYPE_int]], i64 16, i64 4}
 // CHECK-NEW-DAG: [[TAG_NamedBitfields3]] = !{[[TYPE_NamedBitfields3:!.+]], [[TYPE_NamedBitfields3]], i64 0, i64 16}
 // CHECK-NEW-DAG: [[TYPE_NamedBitfields3]] = !{[[TYPE_char]], i64 16, !"_ZTS15NamedBitfields3", [[TYPE_int]], i64 1, i64 4, [[TYPE_int]], i64 2, i64 4, [[TYPE_double]], i64 8, i64 8}
+// CHECK-NEW-DAG: [[TAG_UnionMember1]] = !{[[TYPE_UnionMember1:!.+]], [[TYPE_UnionMember1]], i64 0, i64 16}
+// CHECK-NEW-DAG: [[TYPE_UnionMember1]] = !{[[TYPE_char]], i64 16, !"_ZTS12UnionMember1", [[TYPE_char]], i64 0, i64 8, [[TYPE_int]], i64 8, i64 4}
+// CHECK-NEW-DAG: [[TAG_UnionMember2]] = !{[[TYPE_UnionMember2:!.+]], [[TYPE_UnionMember2]], i64 0, i64 16}
+// CHECK-NEW-DAG: [[TYPE_UnionMember2]] = !{[[TYPE_char]], i64 16, !"_ZTS12UnionMember2", [[TYPE_int]], i64 0, i64 4, [[TYPE_char]], i64 8, i64 8}