Add DISubrangeType

An Ada program can have types that are subranges of other types.  This
patch adds a new DIType node, DISubrangeType, to represent this
concept.

I considered extending the existing DISubrange to do this, but as
DISubrange does not derive from DIType, that approach seemed more
disruptive.

A DISubrangeType can be used both as an ordinary type, but also as the
type of an array index.  This is also important for Ada.

llvm/include/llvm-c/DebugInfo.h

@@ -172,6 +172,7 @@ enum {
   LLVMDIEnumeratorMetadataKind,
   LLVMDIBasicTypeMetadataKind,
   LLVMDIDerivedTypeMetadataKind,
+  LLVMDISubrangeTypeMetadataKind,
   LLVMDICompositeTypeMetadataKind,
   LLVMDISubroutineTypeMetadataKind,
   LLVMDIFileMetadataKind,

llvm/include/llvm/Bitcode/LLVMBitCodes.h

@@ -385,6 +385,7 @@ enum MetadataCodes {
   METADATA_GENERIC_SUBRANGE = 45, // [distinct, count, lo, up, stride]
   METADATA_ARG_LIST = 46,         // [n x [type num, value num]]
   METADATA_ASSIGN_ID = 47,        // [distinct, ...]
+  METADATA_SUBRANGE_TYPE = 48,    // [distinct, ...]
 };
 
 // The constants block (CONSTANTS_BLOCK_ID) describes emission for each

llvm/include/llvm/IR/DIBuilder.h

@@ -667,6 +667,26 @@ namespace llvm {
     /// If \p Implicit is true, also set FlagArtificial.
     static DIType *createObjectPointerType(DIType *Ty, bool Implicit);
 
+    /// Create a type describing a subrange of another type.
+    /// \param Scope          Scope in which this set is defined.
+    /// \param Name           Set name.
+    /// \param File           File where this set is defined.
+    /// \param LineNo         Line number.
+    /// \param SizeInBits     Size.
+    /// \param AlignInBits    Alignment.
+    /// \param Flags          Flags to encode attributes.
+    /// \param Ty             Base type.
+    /// \param LowerBound     Lower bound.
+    /// \param UpperBound     Upper bound.
+    /// \param Stride         Stride, if any.
+    /// \param Bias           Bias, if any.
+    DISubrangeType *
+    createSubrangeType(StringRef Name, DIFile *File, unsigned LineNo,
+                       DIScope *Scope, uint64_t SizeInBits,
+                       uint32_t AlignInBits, DINode::DIFlags Flags, DIType *Ty,
+                       Metadata *LowerBound, Metadata *UpperBound,
+                       Metadata *Stride, Metadata *Bias);
+
     /// Create a permanent forward-declared type.
     DICompositeType *
     createForwardDecl(unsigned Tag, StringRef Name, DIScope *Scope, DIFile *F,

llvm/include/llvm/IR/DebugInfoMetadata.h

@@ -200,6 +200,7 @@ class DINode : public MDNode {
     case DIEnumeratorKind:
     case DIBasicTypeKind:
     case DIStringTypeKind:
+    case DISubrangeTypeKind:
     case DIDerivedTypeKind:
     case DICompositeTypeKind:
     case DISubroutineTypeKind:
@@ -342,9 +343,6 @@ class DIAssignID : public MDNode {
 };
 
 /// Array subrange.
-///
-/// TODO: Merge into node for DW_TAG_array_type, which should have a custom
-/// type.
 class DISubrange : public DINode {
   friend class LLVMContextImpl;
   friend class MDNode;
@@ -550,6 +548,7 @@ class DIScope : public DINode {
       return false;
     case DIBasicTypeKind:
     case DIStringTypeKind:
+    case DISubrangeTypeKind:
     case DIDerivedTypeKind:
     case DICompositeTypeKind:
     case DISubroutineTypeKind:
@@ -808,6 +807,7 @@ class DIType : public DIScope {
       return false;
     case DIBasicTypeKind:
     case DIStringTypeKind:
+    case DISubrangeTypeKind:
     case DIDerivedTypeKind:
     case DICompositeTypeKind:
     case DISubroutineTypeKind:
@@ -1167,6 +1167,97 @@ inline bool operator!=(DIDerivedType::PtrAuthData Lhs,
   return !(Lhs == Rhs);
 }
 
+/// Subrange type.  This is somewhat similar to DISubrange, but it
+/// is also a DIType.
+class DISubrangeType : public DIType {
+public:
+  typedef PointerUnion<ConstantInt *, DIVariable *, DIExpression *> BoundType;
+
+private:
+  friend class LLVMContextImpl;
+  friend class MDNode;
+
+  DISubrangeType(LLVMContext &C, StorageType Storage, unsigned Line,
+                 uint64_t SizeInBits, uint32_t AlignInBits, DIFlags Flags,
+                 ArrayRef<Metadata *> Ops);
+
+  ~DISubrangeType() = default;
+
+  static DISubrangeType *
+  getImpl(LLVMContext &Context, StringRef Name, DIFile *File, unsigned Line,
+          DIScope *Scope, uint64_t SizeInBits, uint32_t AlignInBits,
+          DIFlags Flags, DIType *BaseType, Metadata *LowerBound,
+          Metadata *UpperBound, Metadata *Stride, Metadata *Bias,
+          StorageType Storage, bool ShouldCreate = true) {
+    return getImpl(Context, getCanonicalMDString(Context, Name), File, Line,
+                   Scope, SizeInBits, AlignInBits, Flags, BaseType, LowerBound,
+                   UpperBound, Stride, Bias, Storage, ShouldCreate);
+  }
+
+  static DISubrangeType *getImpl(LLVMContext &Context, MDString *Name,
+                                 Metadata *File, unsigned Line, Metadata *Scope,
+                                 uint64_t SizeInBits, uint32_t AlignInBits,
+                                 DIFlags Flags, Metadata *BaseType,
+                                 Metadata *LowerBound, Metadata *UpperBound,
+                                 Metadata *Stride, Metadata *Bias,
+                                 StorageType Storage, bool ShouldCreate = true);
+
+  TempDISubrangeType cloneImpl() const {
+    return getTemporary(getContext(), getName(), getFile(), getLine(),
+                        getScope(), getSizeInBits(), getAlignInBits(),
+                        getFlags(), getBaseType(), getRawLowerBound(),
+                        getRawUpperBound(), getRawStride(), getRawBias());
+  }
+
+  BoundType convertRawToBound(Metadata *IN) const;
+
+public:
+  DEFINE_MDNODE_GET(DISubrangeType,
+                    (MDString * Name, Metadata *File, unsigned Line,
+                     Metadata *Scope, uint64_t SizeInBits, uint32_t AlignInBits,
+                     DIFlags Flags, Metadata *BaseType, Metadata *LowerBound,
+                     Metadata *UpperBound, Metadata *Stride, Metadata *Bias),
+                    (Name, File, Line, Scope, SizeInBits, AlignInBits, Flags,
+                     BaseType, LowerBound, UpperBound, Stride, Bias))
+  DEFINE_MDNODE_GET(DISubrangeType,
+                    (StringRef Name, DIFile *File, unsigned Line,
+                     DIScope *Scope, uint64_t SizeInBits, uint32_t AlignInBits,
+                     DIFlags Flags, DIType *BaseType, Metadata *LowerBound,
+                     Metadata *UpperBound, Metadata *Stride, Metadata *Bias),
+                    (Name, File, Line, Scope, SizeInBits, AlignInBits, Flags,
+                     BaseType, LowerBound, UpperBound, Stride, Bias))
+
+  TempDISubrangeType clone() const { return cloneImpl(); }
+
+  /// Get the base type this is derived from.
+  DIType *getBaseType() const { return cast_or_null<DIType>(getRawBaseType()); }
+  Metadata *getRawBaseType() const { return getOperand(3); }
+
+  Metadata *getRawLowerBound() const { return getOperand(4).get(); }
+
+  Metadata *getRawUpperBound() const { return getOperand(5).get(); }
+
+  Metadata *getRawStride() const { return getOperand(6).get(); }
+
+  Metadata *getRawBias() const { return getOperand(7).get(); }
+
+  BoundType getLowerBound() const {
+    return convertRawToBound(getRawLowerBound());
+  }
+
+  BoundType getUpperBound() const {
+    return convertRawToBound(getRawUpperBound());
+  }
+
+  BoundType getStride() const { return convertRawToBound(getRawStride()); }
+
+  BoundType getBias() const { return convertRawToBound(getRawBias()); }
+
+  static bool classof(const Metadata *MD) {
+    return MD->getMetadataID() == DISubrangeTypeKind;
+  }
+};
+
 /// Composite types.
 ///
 /// TODO: Detach from DerivedTypeBase (split out MDEnumType?).

llvm/include/llvm/IR/Metadata.def

@@ -118,6 +118,7 @@ HANDLE_SPECIALIZED_MDNODE_LEAF_UNIQUABLE(DIMacroFile)
 HANDLE_SPECIALIZED_MDNODE_LEAF_UNIQUABLE(DICommonBlock)
 HANDLE_SPECIALIZED_MDNODE_LEAF_UNIQUABLE(DIStringType)
 HANDLE_SPECIALIZED_MDNODE_LEAF_UNIQUABLE(DIGenericSubrange)
+HANDLE_SPECIALIZED_MDNODE_LEAF_UNIQUABLE(DISubrangeType)
 
 #undef HANDLE_METADATA
 #undef HANDLE_METADATA_LEAF

llvm/lib/AsmParser/LLParser.cpp

@@ -5318,6 +5318,50 @@ bool LLParser::parseGenericDINode(MDNode *&Result, bool IsDistinct) {
   return false;
 }
 
+/// parseDISubrangeType:
+///   ::= !DISubrangeType(name: "whatever", file: !0,
+///                      line: 7, scope: !1, baseType: !2, size: 32,
+///                      align: 32, flags: 0, lowerBound: !3
+///                      upperBound: !4, stride: !5, bias: !6)
+bool LLParser::parseDISubrangeType(MDNode *&Result, bool IsDistinct) {
+#define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
+  OPTIONAL(name, MDStringField, );                                             \
+  OPTIONAL(file, MDField, );                                                   \
+  OPTIONAL(line, LineField, );                                                 \
+  OPTIONAL(scope, MDField, );                                                  \
+  OPTIONAL(baseType, MDField, );                                               \
+  OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX));                            \
+  OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
+  OPTIONAL(flags, DIFlagField, );                                              \
+  OPTIONAL(lowerBound, MDSignedOrMDField, );                                   \
+  OPTIONAL(upperBound, MDSignedOrMDField, );                                   \
+  OPTIONAL(stride, MDSignedOrMDField, );                                       \
+  OPTIONAL(bias, MDSignedOrMDField, );
+  PARSE_MD_FIELDS();
+#undef VISIT_MD_FIELDS
+
+  auto convToMetadata = [&](MDSignedOrMDField Bound) -> Metadata * {
+    if (Bound.isMDSignedField())
+      return ConstantAsMetadata::get(ConstantInt::getSigned(
+          Type::getInt64Ty(Context), Bound.getMDSignedValue()));
+    if (Bound.isMDField())
+      return Bound.getMDFieldValue();
+    return nullptr;
+  };
+
+  Metadata *LowerBound = convToMetadata(lowerBound);
+  Metadata *UpperBound = convToMetadata(upperBound);
+  Metadata *Stride = convToMetadata(stride);
+  Metadata *Bias = convToMetadata(bias);
+
+  Result = GET_OR_DISTINCT(DISubrangeType,
+                           (Context, name.Val, file.Val, line.Val, scope.Val,
+                            size.Val, align.Val, flags.Val, baseType.Val,
+                            LowerBound, UpperBound, Stride, Bias));
+
+  return false;
+}
+
 /// parseDISubrange:
 ///   ::= !DISubrange(count: 30, lowerBound: 2)
 ///   ::= !DISubrange(count: !node, lowerBound: 2)

llvm/lib/Bitcode/Reader/MetadataLoader.cpp

@@ -1599,6 +1599,24 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     NextMetadataNo++;
     break;
   }
+  case bitc::METADATA_SUBRANGE_TYPE: {
+    if (Record.size() != 13)
+      return error("Invalid record");
+
+    IsDistinct = Record[0];
+    DINode::DIFlags Flags = static_cast<DINode::DIFlags>(Record[7]);
+    MetadataList.assignValue(
+        GET_OR_DISTINCT(DISubrangeType,
+                        (Context, getMDString(Record[1]),
+                         getMDOrNull(Record[2]), Record[3],
+                         getMDOrNull(Record[4]), Record[5], Record[6], Flags,
+                         getDITypeRefOrNull(Record[8]), getMDOrNull(Record[9]),
+                         getMDOrNull(Record[10]), getMDOrNull(Record[11]),
+                         getMDOrNull(Record[12]))),
+        NextMetadataNo);
+    NextMetadataNo++;
+    break;
+  }
   case bitc::METADATA_COMPOSITE_TYPE: {
     if (Record.size() < 16 || Record.size() > 25)
       return error("Invalid record");

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -327,6 +327,8 @@ class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
   void writeDIDerivedType(const DIDerivedType *N,
                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
+  void writeDISubrangeType(const DISubrangeType *N,
+                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
   void writeDICompositeType(const DICompositeType *N,
                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
   void writeDISubroutineType(const DISubroutineType *N,
@@ -1930,6 +1932,27 @@ void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
   Record.clear();
 }
 
+void ModuleBitcodeWriter::writeDISubrangeType(const DISubrangeType *N,
+                                              SmallVectorImpl<uint64_t> &Record,
+                                              unsigned Abbrev) {
+  Record.push_back(N->isDistinct());
+  Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
+  Record.push_back(VE.getMetadataOrNullID(N->getFile()));
+  Record.push_back(N->getLine());
+  Record.push_back(VE.getMetadataOrNullID(N->getScope()));
+  Record.push_back(N->getSizeInBits());
+  Record.push_back(N->getAlignInBits());
+  Record.push_back(N->getFlags());
+  Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
+  Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
+  Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
+  Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
+  Record.push_back(VE.getMetadataOrNullID(N->getRawBias()));
+
+  Stream.EmitRecord(bitc::METADATA_SUBRANGE_TYPE, Record, Abbrev);
+  Record.clear();
+}
+
 void ModuleBitcodeWriter::writeDICompositeType(
     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
     unsigned Abbrev) {

llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp

@@ -161,6 +161,8 @@ uint64_t DebugHandlerBase::getBaseTypeSize(const DIType *Ty) {
   DIType *BaseType = nullptr;
   if (const DIDerivedType *DDTy = dyn_cast<DIDerivedType>(Ty))
     BaseType = DDTy->getBaseType();
+  else if (const DISubrangeType *SRTy = dyn_cast<DISubrangeType>(Ty))
+    BaseType = SRTy->getBaseType();
 
   if (!BaseType)
     return 0;
@@ -186,6 +188,12 @@ bool DebugHandlerBase::isUnsignedDIType(const DIType *Ty) {
     return true;
   }
 
+  if (auto *SRTy = dyn_cast<DISubrangeType>(Ty)) {
+    Ty = SRTy->getBaseType();
+    if (!Ty)
+      return false;
+  }
+
   if (auto *CTy = dyn_cast<DICompositeType>(Ty)) {
     if (CTy->getTag() == dwarf::DW_TAG_enumeration_type) {
       if (!(Ty = CTy->getBaseType()))