[clang][DWARF] Add DW_AT_bit_stride for SVE predicate types (#161409)

Fixes #159285

Author: marykass-arm

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -900,10 +900,13 @@ llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
       assert((BT->getKind() != BuiltinType::SveCount || Info.NumVectors == 1) &&
              "Unsupported number of vectors for svcount_t");
 
-      // Debuggers can't extract 1bit from a vector, so will display a
-      // bitpattern for predicates instead.
       unsigned NumElems = Info.EC.getKnownMinValue() * Info.NumVectors;
-      if (Info.ElementType == CGM.getContext().BoolTy) {
+      llvm::Metadata *BitStride = nullptr;
+      if (BT->getKind() == BuiltinType::SveBool) {
+        Info.ElementType = CGM.getContext().UnsignedCharTy;
+        BitStride = llvm::ConstantAsMetadata::get(llvm::ConstantInt::getSigned(
+            llvm::Type::getInt64Ty(CGM.getLLVMContext()), 1));
+      } else if (BT->getKind() == BuiltinType::SveCount) {
         NumElems /= 8;
         Info.ElementType = CGM.getContext().UnsignedCharTy;
       }
@@ -929,7 +932,7 @@ llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
           getOrCreateType(Info.ElementType, TheCU->getFile());
       auto Align = getTypeAlignIfRequired(BT, CGM.getContext());
       return DBuilder.createVectorType(/*Size*/ 0, Align, ElemTy,
-                                       SubscriptArray);
+                                       SubscriptArray, BitStride);
     }
   // It doesn't make sense to generate debug info for PowerPC MMA vector types.
   // So we return a safe type here to avoid generating an error.

clang/test/DebugInfo/AArch64/sve-vector-types.c

@@ -3,10 +3,10 @@
 
 void test_locals(void) {
   // CHECK-DAG: name: "__SVBool_t",{{.*}}, baseType: ![[CT1:[0-9]+]]
-  // CHECK-DAG: ![[CT1]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTYU8:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS1_64:[0-9]+]])
+  // CHECK-DAG: ![[CT1]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTYU8:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS8:[0-9]+]], bitStride: i64 1)
   // CHECK-DAG: ![[ELTTYU8]] = !DIBasicType(name: "unsigned char", size: 8, encoding: DW_ATE_unsigned_char)
-  // CHECK-DAG: ![[ELTS1_64]] = !{![[REALELTS1_64:[0-9]+]]}
-  // CHECK-DAG: ![[REALELTS1_64]] = !DISubrange(lowerBound: 0, upperBound: !DIExpression(DW_OP_constu, 1, DW_OP_bregx, 46, 0, DW_OP_mul, DW_OP_constu, 1, DW_OP_minus))
+  // CHECK-DAG: ![[ELTS8]] = !{![[REALELTS8:[0-9]+]]}
+  // CHECK-DAG: ![[REALELTS8]] = !DISubrange(lowerBound: 0, upperBound: !DIExpression(DW_OP_constu, 8, DW_OP_bregx, 46, 0, DW_OP_mul, DW_OP_constu, 1, DW_OP_minus))
   __SVBool_t b8;
 
   // CHECK-DAG: name: "__SVCount_t",{{.*}}, baseType: ![[CT1_2:[0-9]+]]
@@ -18,8 +18,6 @@ void test_locals(void) {
   // CHECK-DAG: name: "__SVInt8_t",{{.*}}, baseType: ![[CT8:[0-9]+]]
   // CHECK-DAG: ![[CT8]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTYS8:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS8:[0-9]+]])
   // CHECK-DAG: ![[ELTTYS8]] = !DIBasicType(name: "signed char", size: 8, encoding: DW_ATE_signed_char)
-  // CHECK-DAG: ![[ELTS8]] = !{![[REALELTS8:[0-9]+]]}
-  // CHECK-DAG: ![[REALELTS8]] = !DISubrange(lowerBound: 0, upperBound: !DIExpression(DW_OP_constu, 8, DW_OP_bregx, 46, 0, DW_OP_mul, DW_OP_constu, 1, DW_OP_minus))
   __SVInt8_t s8;
 
   // CHECK-DAG: name: "__SVUint8_t",{{.*}}, baseType: ![[CT8:[0-9]+]]
@@ -51,12 +49,14 @@ void test_locals(void) {
   __SVUint32_t u32;
 
   // CHECK-DAG: name: "__SVInt64_t",{{.*}}, baseType: ![[CT64:[0-9]+]]
-  // CHECK-DAG: ![[CT64]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTY64:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS1_64]])
+  // CHECK-DAG: ![[CT64]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTY64:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS64:[0-9]+]])
   // CHECK-DAG: ![[ELTTY64]] = !DIBasicType(name: "long", size: 64, encoding: DW_ATE_signed)
+  // CHECK-DAG: ![[ELTS64]] = !{![[REALELTS64:[0-9]+]]}
+  // CHECK-DAG: ![[REALELTS64]] = !DISubrange(lowerBound: 0, upperBound: !DIExpression(DW_OP_constu, 1, DW_OP_bregx, 46, 0, DW_OP_mul, DW_OP_constu, 1, DW_OP_minus))
   __SVInt64_t s64;
 
   // CHECK-DAG: name: "__SVUint64_t",{{.*}}, baseType: ![[CT64:[0-9]+]]
-  // CHECK-DAG: ![[CT64]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTY64:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS1_64]])
+  // CHECK-DAG: ![[CT64]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTY64:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS64]])
   // CHECK-DAG: ![[ELTTY64]] = !DIBasicType(name: "unsigned long", size: 64, encoding: DW_ATE_unsigned)
   __SVUint64_t u64;
 
@@ -71,7 +71,7 @@ void test_locals(void) {
   __SVFloat32_t f32;
 
   // CHECK:     name: "__SVFloat64_t",{{.*}}, baseType: ![[CT64:[0-9]+]]
-  // CHECK-DAG: ![[CT64]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTY64:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS1_64]])
+  // CHECK-DAG: ![[CT64]] = !DICompositeType(tag: DW_TAG_array_type, baseType: ![[ELTTY64:[0-9]+]], flags: DIFlagVector, elements: ![[ELTS64]])
   // CHECK-DAG: ![[ELTTY64]] = !DIBasicType(name: "double", size: 64, encoding: DW_ATE_float)
   __SVFloat64_t f64;
 }

llvm/include/llvm/IR/DIBuilder.h

@@ -729,7 +729,8 @@ namespace llvm {
     /// \param Subscripts   Subscripts.
     LLVM_ABI DICompositeType *createVectorType(uint64_t Size,
                                                uint32_t AlignInBits, DIType *Ty,
-                                               DINodeArray Subscripts);
+                                               DINodeArray Subscripts,
+                                               Metadata *BitStride = nullptr);
 
     /// Create debugging information entry for an
     /// enumeration.

llvm/lib/IR/DIBuilder.cpp

@@ -715,11 +715,20 @@ DICompositeType *DIBuilder::createArrayType(
 
 DICompositeType *DIBuilder::createVectorType(uint64_t Size,
                                              uint32_t AlignInBits, DIType *Ty,
-                                             DINodeArray Subscripts) {
-  auto *R = DICompositeType::get(VMContext, dwarf::DW_TAG_array_type, "",
-                                 nullptr, 0, nullptr, Ty, Size, AlignInBits, 0,
-                                 DINode::FlagVector, Subscripts, 0,
-                                 /*EnumKind=*/std::nullopt, nullptr);
+                                             DINodeArray Subscripts,
+                                             Metadata *BitStride) {
+  auto *R = DICompositeType::get(
+      VMContext, dwarf::DW_TAG_array_type, /*Name=*/"",
+      /*File=*/nullptr, /*Line=*/0, /*Scope=*/nullptr, /*BaseType=*/Ty,
+      /*SizeInBits=*/Size, /*AlignInBits=*/AlignInBits, /*OffsetInBits=*/0,
+      /*Flags=*/DINode::FlagVector, /*Elements=*/Subscripts,
+      /*RuntimeLang=*/0, /*EnumKind=*/std::nullopt, /*VTableHolder=*/nullptr,
+      /*TemplateParams=*/nullptr, /*Identifier=*/"",
+      /*Discriminator=*/nullptr, /*DataLocation=*/nullptr,
+      /*Associated=*/nullptr, /*Allocated=*/nullptr, /*Rank=*/nullptr,
+      /*Annotations=*/nullptr, /*Specification=*/nullptr,
+      /*NumExtraInhabitants=*/0,
+      /*BitStride=*/BitStride);
   trackIfUnresolved(R);
   return R;
 }