text: //===- DIBuilder.h - Debug Information Builder ------------------*- C++ -*-===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  // This file defines a DIBuilder that is useful for creating debugging
  // information entries in LLVM IR form.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_IR_DIBUILDER_H
  #define LLVM_IR_DIBUILDER_H
  
  #include "llvm/ADT/ArrayRef.h"
  #include "llvm/ADT/DenseMap.h"
  #include "llvm/ADT/MapVector.h"
  #include "llvm/ADT/Optional.h"
  #include "llvm/ADT/SetVector.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/IR/DebugInfo.h"
  #include "llvm/IR/DebugInfoMetadata.h"
  #include "llvm/IR/TrackingMDRef.h"
  #include "llvm/Support/Casting.h"
  #include <algorithm>
  #include <cstdint>
  
  namespace llvm {
  
    class BasicBlock;
    class Constant;
    class Function;
    class Instruction;
    class LLVMContext;
    class Module;
    class Value;
  
    class DIBuilder {
      Module &M;
      LLVMContext &VMContext;
  
      DICompileUnit *CUNode;   ///< The one compile unit created by this DIBuiler.
      Function *DeclareFn;     ///< llvm.dbg.declare
      Function *ValueFn;       ///< llvm.dbg.value
      Function *LabelFn;       ///< llvm.dbg.label
  
      SmallVector<Metadata *, 4> AllEnumTypes;
      /// Track the RetainTypes, since they can be updated later on.
      SmallVector<TrackingMDNodeRef, 4> AllRetainTypes;
      SmallVector<Metadata *, 4> AllSubprograms;
      SmallVector<Metadata *, 4> AllGVs;
      SmallVector<TrackingMDNodeRef, 4> AllImportedModules;
      /// Map Macro parent (which can be DIMacroFile or nullptr) to a list of
      /// Metadata all of type DIMacroNode.
      /// DIMacroNode's with nullptr parent are DICompileUnit direct children.
      MapVector<MDNode *, SetVector<Metadata *>> AllMacrosPerParent;
  
      /// Track nodes that may be unresolved.
      SmallVector<TrackingMDNodeRef, 4> UnresolvedNodes;
      bool AllowUnresolvedNodes;
  
      /// Each subprogram's preserved local variables.
      ///
      /// Do not use a std::vector.  Some versions of libc++ apparently copy
      /// instead of move on grow operations, and TrackingMDRef is expensive to
      /// copy.
      DenseMap<MDNode *, SmallVector<TrackingMDNodeRef, 1>> PreservedVariables;
  
      /// Each subprogram's preserved labels.
      DenseMap<MDNode *, SmallVector<TrackingMDNodeRef, 1>> PreservedLabels;
  
      /// Create a temporary.
      ///
      /// Create an \a temporary node and track it in \a UnresolvedNodes.
      void trackIfUnresolved(MDNode *N);
  
      /// Internal helper for insertDeclare.
      Instruction *insertDeclare(llvm::Value *Storage, DILocalVariable *VarInfo,
                                 DIExpression *Expr, const DILocation *DL,
                                 BasicBlock *InsertBB, Instruction *InsertBefore);
  
      /// Internal helper for insertLabel.
      Instruction *insertLabel(DILabel *LabelInfo, const DILocation *DL,
                               BasicBlock *InsertBB, Instruction *InsertBefore);
  
      /// Internal helper for insertDbgValueIntrinsic.
      Instruction *
      insertDbgValueIntrinsic(llvm::Value *Val, DILocalVariable *VarInfo,
                              DIExpression *Expr, const DILocation *DL,
                              BasicBlock *InsertBB, Instruction *InsertBefore);
  
    public:
      /// Construct a builder for a module.
      ///
      /// If \c AllowUnresolved, collect unresolved nodes attached to the module
      /// in order to resolve cycles during \a finalize().
      ///
      /// If \p CU is given a value other than nullptr, then set \p CUNode to CU.
      explicit DIBuilder(Module &M, bool AllowUnresolved = true,
                         DICompileUnit *CU = nullptr);
      DIBuilder(const DIBuilder &) = delete;
      DIBuilder &operator=(const DIBuilder &) = delete;
  
      /// Construct any deferred debug info descriptors.
      void finalize();
  
      /// Finalize a specific subprogram - no new variables may be added to this
      /// subprogram afterwards.
      void finalizeSubprogram(DISubprogram *SP);
  
      /// A CompileUnit provides an anchor for all debugging
      /// information generated during this instance of compilation.
      /// \param Lang          Source programming language, eg. dwarf::DW_LANG_C99
      /// \param File          File info.
      /// \param Producer      Identify the producer of debugging information
      ///                      and code.  Usually this is a compiler
      ///                      version string.
      /// \param isOptimized   A boolean flag which indicates whether optimization
      ///                      is enabled or not.
      /// \param Flags         This string lists command line options. This
      ///                      string is directly embedded in debug info
      ///                      output which may be used by a tool
      ///                      analyzing generated debugging information.
      /// \param RV            This indicates runtime version for languages like
      ///                      Objective-C.
      /// \param SplitName     The name of the file that we'll split debug info
      ///                      out into.
      /// \param Kind          The kind of debug information to generate.
      /// \param DWOId         The DWOId if this is a split skeleton compile unit.
      /// \param SplitDebugInlining    Whether to emit inline debug info.
      /// \param DebugInfoForProfiling Whether to emit extra debug info for
      ///                              profile collection.
      /// \param NameTableKind  Whether to emit .debug_gnu_pubnames,
      ///                      .debug_pubnames, or no pubnames at all.
      /// \param SysRoot       The clang system root (value of -isysroot).
      /// \param SDK           The SDK name. On Darwin, this is the last component
      ///                      of the sysroot.
      DICompileUnit *
      createCompileUnit(unsigned Lang, DIFile *File, StringRef Producer,
                        bool isOptimized, StringRef Flags, unsigned RV,
                        StringRef SplitName = StringRef(),
                        DICompileUnit::DebugEmissionKind Kind =
                            DICompileUnit::DebugEmissionKind::FullDebug,
                        uint64_t DWOId = 0, bool SplitDebugInlining = true,
                        bool DebugInfoForProfiling = false,
                        DICompileUnit::DebugNameTableKind NameTableKind =
                            DICompileUnit::DebugNameTableKind::Default,
                        bool RangesBaseAddress = false, StringRef SysRoot = {},
                        StringRef SDK = {});
  
      /// Create a file descriptor to hold debugging information for a file.
      /// \param Filename  File name.
      /// \param Directory Directory.
      /// \param Checksum  Optional checksum kind (e.g. CSK_MD5, CSK_SHA1, etc.)
      ///                  and value.
      /// \param Source    Optional source text.
      DIFile *
      createFile(StringRef Filename, StringRef Directory,
                 Optional<DIFile::ChecksumInfo<StringRef>> Checksum = None,
                 Optional<StringRef> Source = None);
  
      /// Create debugging information entry for a macro.
      /// \param Parent     Macro parent (could be nullptr).
      /// \param Line       Source line number where the macro is defined.
      /// \param MacroType  DW_MACINFO_define or DW_MACINFO_undef.
      /// \param Name       Macro name.
      /// \param Value      Macro value.
      DIMacro *createMacro(DIMacroFile *Parent, unsigned Line, unsigned MacroType,
                           StringRef Name, StringRef Value = StringRef());
  
      /// Create debugging information temporary entry for a macro file.
      /// List of macro node direct children will be calculated by DIBuilder,
      /// using the \p Parent relationship.
      /// \param Parent     Macro file parent (could be nullptr).
      /// \param Line       Source line number where the macro file is included.
      /// \param File       File descriptor containing the name of the macro file.
      DIMacroFile *createTempMacroFile(DIMacroFile *Parent, unsigned Line,
                                       DIFile *File);
  
      /// Create a single enumerator value.
      DIEnumerator *createEnumerator(StringRef Name, int64_t Val, bool IsUnsigned = false);
  
      /// Create a DWARF unspecified type.
      DIBasicType *createUnspecifiedType(StringRef Name);
  
      /// Create C++11 nullptr type.
      DIBasicType *createNullPtrType();
  
      /// Create debugging information entry for a basic
      /// type.
      /// \param Name        Type name.
      /// \param SizeInBits  Size of the type.
      /// \param Encoding    DWARF encoding code, e.g., dwarf::DW_ATE_float.
      /// \param Flags       Optional DWARF attributes, e.g., DW_AT_endianity.
      DIBasicType *createBasicType(StringRef Name, uint64_t SizeInBits,
                                   unsigned Encoding,
                                   DINode::DIFlags Flags = DINode::FlagZero);
  
      /// Create debugging information entry for a qualified
      /// type, e.g. 'const int'.
      /// \param Tag         Tag identifing type, e.g. dwarf::TAG_volatile_type
      /// \param FromTy      Base Type.
      DIDerivedType *createQualifiedType(unsigned Tag, DIType *FromTy);
  
      /// Create debugging information entry for a pointer.
      /// \param PointeeTy         Type pointed by this pointer.
      /// \param SizeInBits        Size.
      /// \param AlignInBits       Alignment. (optional)
      /// \param DWARFAddressSpace DWARF address space. (optional)
      /// \param Name              Pointer type name. (optional)
      DIDerivedType *createPointerType(DIType *PointeeTy, uint64_t SizeInBits,
                                       uint32_t AlignInBits = 0,
                                       Optional<unsigned> DWARFAddressSpace =
                                           None,
                                       StringRef Name = "");
  
      /// Create debugging information entry for a pointer to member.
      /// \param PointeeTy Type pointed to by this pointer.
      /// \param SizeInBits  Size.
      /// \param AlignInBits Alignment. (optional)
      /// \param Class Type for which this pointer points to members of.
      DIDerivedType *
      createMemberPointerType(DIType *PointeeTy, DIType *Class,
                              uint64_t SizeInBits, uint32_t AlignInBits = 0,
                              DINode::DIFlags Flags = DINode::FlagZero);
  
      /// Create debugging information entry for a c++
      /// style reference or rvalue reference type.
      DIDerivedType *createReferenceType(unsigned Tag, DIType *RTy,
                                         uint64_t SizeInBits = 0,
                                         uint32_t AlignInBits = 0,
                                         Optional<unsigned> DWARFAddressSpace =
                                             None);
  
      /// Create debugging information entry for a typedef.
      /// \param Ty          Original type.
      /// \param Name        Typedef name.
      /// \param File        File where this type is defined.
      /// \param LineNo      Line number.
      /// \param Context     The surrounding context for the typedef.
      /// \param AlignInBits Alignment. (optional)
      DIDerivedType *createTypedef(DIType *Ty, StringRef Name, DIFile *File,
                                   unsigned LineNo, DIScope *Context,
                                   uint32_t AlignInBits = 0);
  
      /// Create debugging information entry for a 'friend'.
      DIDerivedType *createFriend(DIType *Ty, DIType *FriendTy);
  
      /// Create debugging information entry to establish
      /// inheritance relationship between two types.
      /// \param Ty           Original type.
      /// \param BaseTy       Base type. Ty is inherits from base.
      /// \param BaseOffset   Base offset.
      /// \param VBPtrOffset  Virtual base pointer offset.
      /// \param Flags        Flags to describe inheritance attribute,
      ///                     e.g. private
      DIDerivedType *createInheritance(DIType *Ty, DIType *BaseTy,
                                       uint64_t BaseOffset, uint32_t VBPtrOffset,
                                       DINode::DIFlags Flags);
  
      /// Create debugging information entry for a member.
      /// \param Scope        Member scope.
      /// \param Name         Member name.
      /// \param File         File where this member is defined.
      /// \param LineNo       Line number.
      /// \param SizeInBits   Member size.
      /// \param AlignInBits  Member alignment.
      /// \param OffsetInBits Member offset.
      /// \param Flags        Flags to encode member attribute, e.g. private
      /// \param Ty           Parent type.
      DIDerivedType *createMemberType(DIScope *Scope, StringRef Name,
                                      DIFile *File, unsigned LineNo,
                                      uint64_t SizeInBits,
                                      uint32_t AlignInBits,
                                      uint64_t OffsetInBits,
                                      DINode::DIFlags Flags, DIType *Ty);
  
      /// Create debugging information entry for a variant.  A variant
      /// normally should be a member of a variant part.
      /// \param Scope        Member scope.
      /// \param Name         Member name.
      /// \param File         File where this member is defined.
      /// \param LineNo       Line number.
      /// \param SizeInBits   Member size.
      /// \param AlignInBits  Member alignment.
      /// \param OffsetInBits Member offset.
      /// \param Flags        Flags to encode member attribute, e.g. private
      /// \param Discriminant The discriminant for this branch; null for
      ///                     the default branch
      /// \param Ty           Parent type.
      DIDerivedType *createVariantMemberType(DIScope *Scope, StringRef Name,
  					   DIFile *File, unsigned LineNo,
  					   uint64_t SizeInBits,
  					   uint32_t AlignInBits,
  					   uint64_t OffsetInBits,
  					   Constant *Discriminant,
  					   DINode::DIFlags Flags, DIType *Ty);
  
      /// Create debugging information entry for a bit field member.
      /// \param Scope               Member scope.
      /// \param Name                Member name.
      /// \param File                File where this member is defined.
      /// \param LineNo              Line number.
      /// \param SizeInBits          Member size.
      /// \param OffsetInBits        Member offset.
      /// \param StorageOffsetInBits Member storage offset.
      /// \param Flags               Flags to encode member attribute.
      /// \param Ty                  Parent type.
      DIDerivedType *createBitFieldMemberType(
          DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNo,
          uint64_t SizeInBits, uint64_t OffsetInBits,
          uint64_t StorageOffsetInBits, DINode::DIFlags Flags, DIType *Ty);
  
      /// Create debugging information entry for a
      /// C++ static data member.
      /// \param Scope      Member scope.
      /// \param Name       Member name.
      /// \param File       File where this member is declared.
      /// \param LineNo     Line number.
      /// \param Ty         Type of the static member.
      /// \param Flags      Flags to encode member attribute, e.g. private.
      /// \param Val        Const initializer of the member.
      /// \param AlignInBits  Member alignment.
      DIDerivedType *createStaticMemberType(DIScope *Scope, StringRef Name,
                                            DIFile *File, unsigned LineNo,
                                            DIType *Ty, DINode::DIFlags Flags,
                                            Constant *Val,
                                            uint32_t AlignInBits = 0);
  
      /// Create debugging information entry for Objective-C
      /// instance variable.
      /// \param Name         Member name.
      /// \param File         File where this member is defined.
      /// \param LineNo       Line number.
      /// \param SizeInBits   Member size.
      /// \param AlignInBits  Member alignment.
      /// \param OffsetInBits Member offset.
      /// \param Flags        Flags to encode member attribute, e.g. private
      /// \param Ty           Parent type.
      /// \param PropertyNode Property associated with this ivar.
      DIDerivedType *createObjCIVar(StringRef Name, DIFile *File, unsigned LineNo,
                                    uint64_t SizeInBits, uint32_t AlignInBits,
                                    uint64_t OffsetInBits, DINode::DIFlags Flags,
                                    DIType *Ty, MDNode *PropertyNode);
  
      /// Create debugging information entry for Objective-C
      /// property.
      /// \param Name         Property name.
      /// \param File         File where this property is defined.
      /// \param LineNumber   Line number.
      /// \param GetterName   Name of the Objective C property getter selector.
      /// \param SetterName   Name of the Objective C property setter selector.
      /// \param PropertyAttributes Objective C property attributes.
      /// \param Ty           Type.
      DIObjCProperty *createObjCProperty(StringRef Name, DIFile *File,
                                         unsigned LineNumber,
                                         StringRef GetterName,
                                         StringRef SetterName,
                                         unsigned PropertyAttributes, DIType *Ty);
  
      /// Create debugging information entry for a class.
      /// \param Scope        Scope in which this class is defined.
      /// \param Name         class name.
      /// \param File         File where this member is defined.
      /// \param LineNumber   Line number.
      /// \param SizeInBits   Member size.
      /// \param AlignInBits  Member alignment.
      /// \param OffsetInBits Member offset.
      /// \param Flags        Flags to encode member attribute, e.g. private
      /// \param Elements     class members.
      /// \param VTableHolder Debug info of the base class that contains vtable
      ///                     for this type. This is used in
      ///                     DW_AT_containing_type. See DWARF documentation
      ///                     for more info.
      /// \param TemplateParms Template type parameters.
      /// \param UniqueIdentifier A unique identifier for the class.
      DICompositeType *createClassType(
          DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
          uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
          DINode::DIFlags Flags, DIType *DerivedFrom, DINodeArray Elements,
          DIType *VTableHolder = nullptr, MDNode *TemplateParms = nullptr,
          StringRef UniqueIdentifier = "");
  
      /// Create debugging information entry for a struct.
      /// \param Scope        Scope in which this struct is defined.
      /// \param Name         Struct name.
      /// \param File         File where this member is defined.
      /// \param LineNumber   Line number.
      /// \param SizeInBits   Member size.
      /// \param AlignInBits  Member alignment.
      /// \param Flags        Flags to encode member attribute, e.g. private
      /// \param Elements     Struct elements.
      /// \param RunTimeLang  Optional parameter, Objective-C runtime version.
      /// \param UniqueIdentifier A unique identifier for the struct.
      DICompositeType *createStructType(
          DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
          uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
          DIType *DerivedFrom, DINodeArray Elements, unsigned RunTimeLang = 0,
          DIType *VTableHolder = nullptr, StringRef UniqueIdentifier = "");
  
      /// Create debugging information entry for an union.
      /// \param Scope        Scope in which this union is defined.
      /// \param Name         Union name.
      /// \param File         File where this member is defined.
      /// \param LineNumber   Line number.
      /// \param SizeInBits   Member size.
      /// \param AlignInBits  Member alignment.
      /// \param Flags        Flags to encode member attribute, e.g. private
      /// \param Elements     Union elements.
      /// \param RunTimeLang  Optional parameter, Objective-C runtime version.
      /// \param UniqueIdentifier A unique identifier for the union.
      DICompositeType *createUnionType(DIScope *Scope, StringRef Name,
                                       DIFile *File, unsigned LineNumber,
                                       uint64_t SizeInBits, uint32_t AlignInBits,
                                       DINode::DIFlags Flags,
                                       DINodeArray Elements,
                                       unsigned RunTimeLang = 0,
                                       StringRef UniqueIdentifier = "");
  
      /// Create debugging information entry for a variant part.  A
      /// variant part normally has a discriminator (though this is not
      /// required) and a number of variant children.
      /// \param Scope        Scope in which this union is defined.
      /// \param Name         Union name.
      /// \param File         File where this member is defined.
      /// \param LineNumber   Line number.
      /// \param SizeInBits   Member size.
      /// \param AlignInBits  Member alignment.
      /// \param Flags        Flags to encode member attribute, e.g. private
      /// \param Discriminator Discriminant member
      /// \param Elements     Variant elements.
      /// \param UniqueIdentifier A unique identifier for the union.
      DICompositeType *createVariantPart(DIScope *Scope, StringRef Name,
  				       DIFile *File, unsigned LineNumber,
  				       uint64_t SizeInBits, uint32_t AlignInBits,
  				       DINode::DIFlags Flags,
  				       DIDerivedType *Discriminator,
  				       DINodeArray Elements,
  				       StringRef UniqueIdentifier = "");
  
      /// Create debugging information for template
      /// type parameter.
      /// \param Scope        Scope in which this type is defined.
      /// \param Name         Type parameter name.
      /// \param Ty           Parameter type.
      /// \param IsDefault    Parameter is default or not
      DITemplateTypeParameter *createTemplateTypeParameter(DIScope *Scope,
                                                           StringRef Name,
                                                           DIType *Ty,
                                                           bool IsDefault);
  
      /// Create debugging information for template
      /// value parameter.
      /// \param Scope        Scope in which this type is defined.
      /// \param Name         Value parameter name.
      /// \param Ty           Parameter type.
      /// \param IsDefault    Parameter is default or not
      /// \param Val          Constant parameter value.
      DITemplateValueParameter *
      createTemplateValueParameter(DIScope *Scope, StringRef Name, DIType *Ty,
                                   bool IsDefault, Constant *Val);
  
      /// Create debugging information for a template template parameter.
      /// \param Scope        Scope in which this type is defined.
      /// \param Name         Value parameter name.
      /// \param Ty           Parameter type.
      /// \param Val          The fully qualified name of the template.
      DITemplateValueParameter *createTemplateTemplateParameter(DIScope *Scope,
                                                                StringRef Name,
                                                                DIType *Ty,
                                                                StringRef Val);
  
      /// Create debugging information for a template parameter pack.
      /// \param Scope        Scope in which this type is defined.
      /// \param Name         Value parameter name.
      /// \param Ty           Parameter type.
      /// \param Val          An array of types in the pack.
      DITemplateValueParameter *createTemplateParameterPack(DIScope *Scope,
                                                            StringRef Name,
                                                            DIType *Ty,
                                                            DINodeArray Val);
  
      /// Create debugging information entry for an array.
      /// \param Size         Array size.
      /// \param AlignInBits  Alignment.
      /// \param Ty           Element type.
      /// \param Subscripts   Subscripts.
      DICompositeType *createArrayType(uint64_t Size, uint32_t AlignInBits,
                                       DIType *Ty, DINodeArray Subscripts);
  
      /// Create debugging information entry for a vector type.
      /// \param Size         Array size.
      /// \param AlignInBits  Alignment.
      /// \param Ty           Element type.
      /// \param Subscripts   Subscripts.
      DICompositeType *createVectorType(uint64_t Size, uint32_t AlignInBits,
                                        DIType *Ty, DINodeArray Subscripts);
  
      /// Create debugging information entry for an
      /// enumeration.
      /// \param Scope          Scope in which this enumeration is defined.
      /// \param Name           Union name.
      /// \param File           File where this member is defined.
      /// \param LineNumber     Line number.
      /// \param SizeInBits     Member size.
      /// \param AlignInBits    Member alignment.
      /// \param Elements       Enumeration elements.
      /// \param UnderlyingType Underlying type of a C++11/ObjC fixed enum.
      /// \param UniqueIdentifier A unique identifier for the enum.
      /// \param IsScoped Boolean flag indicate if this is C++11/ObjC 'enum class'.
      DICompositeType *createEnumerationType(
          DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
          uint64_t SizeInBits, uint32_t AlignInBits, DINodeArray Elements,
          DIType *UnderlyingType, StringRef UniqueIdentifier = "", bool IsScoped = false);
  
      /// Create subroutine type.
      /// \param ParameterTypes  An array of subroutine parameter types. This
      ///                        includes return type at 0th index.
      /// \param Flags           E.g.: LValueReference.
      ///                        These flags are used to emit dwarf attributes.
      /// \param CC              Calling convention, e.g. dwarf::DW_CC_normal
      DISubroutineType *
      createSubroutineType(DITypeRefArray ParameterTypes,
                           DINode::DIFlags Flags = DINode::FlagZero,
                           unsigned CC = 0);
  
      /// Create a distinct clone of \p SP with FlagArtificial set.
      static DISubprogram *createArtificialSubprogram(DISubprogram *SP);
  
      /// Create a uniqued clone of \p Ty with FlagArtificial set.
      static DIType *createArtificialType(DIType *Ty);
  
      /// Create a uniqued clone of \p Ty with FlagObjectPointer and
      /// FlagArtificial set.
      static DIType *createObjectPointerType(DIType *Ty);
  
      /// Create a permanent forward-declared type.
      DICompositeType *createForwardDecl(unsigned Tag, StringRef Name,
                                         DIScope *Scope, DIFile *F, unsigned Line,
                                         unsigned RuntimeLang = 0,
                                         uint64_t SizeInBits = 0,
                                         uint32_t AlignInBits = 0,
                                         StringRef UniqueIdentifier = "");
  
      /// Create a temporary forward-declared type.
      DICompositeType *createReplaceableCompositeType(
          unsigned Tag, StringRef Name, DIScope *Scope, DIFile *F, unsigned Line,
          unsigned RuntimeLang = 0, uint64_t SizeInBits = 0,
          uint32_t AlignInBits = 0, DINode::DIFlags Flags = DINode::FlagFwdDecl,
          StringRef UniqueIdentifier = "");
  
      /// Retain DIScope* in a module even if it is not referenced
      /// through debug info anchors.
      void retainType(DIScope *T);
  
      /// Create unspecified parameter type
      /// for a subroutine type.
      DIBasicType *createUnspecifiedParameter();
  
      /// Get a DINodeArray, create one if required.
      DINodeArray getOrCreateArray(ArrayRef<Metadata *> Elements);
  
      /// Get a DIMacroNodeArray, create one if required.
      DIMacroNodeArray getOrCreateMacroArray(ArrayRef<Metadata *> Elements);
  
      /// Get a DITypeRefArray, create one if required.
      DITypeRefArray getOrCreateTypeArray(ArrayRef<Metadata *> Elements);
  
      /// Create a descriptor for a value range.  This
      /// implicitly uniques the values returned.
      DISubrange *getOrCreateSubrange(int64_t Lo, int64_t Count);
      DISubrange *getOrCreateSubrange(int64_t Lo, Metadata *CountNode);
      DISubrange *getOrCreateSubrange(Metadata *Count, Metadata *LowerBound,
                                      Metadata *UpperBound, Metadata *Stride);
  
      /// Create a new descriptor for the specified variable.
      /// \param Context     Variable scope.
      /// \param Name        Name of the variable.
      /// \param LinkageName Mangled  name of the variable.
      /// \param File        File where this variable is defined.
      /// \param LineNo      Line number.
      /// \param Ty          Variable Type.
      /// \param IsLocalToUnit Boolean flag indicate whether this variable is
      ///                      externally visible or not.
      /// \param Expr        The location of the global relative to the attached
      ///                    GlobalVariable.
      /// \param Decl        Reference to the corresponding declaration.
      /// \param AlignInBits Variable alignment(or 0 if no alignment attr was
      ///                    specified)
      DIGlobalVariableExpression *createGlobalVariableExpression(
          DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
          unsigned LineNo, DIType *Ty, bool IsLocalToUnit, bool isDefined = true,
          DIExpression *Expr = nullptr, MDNode *Decl = nullptr,
          MDTuple *TemplateParams = nullptr, uint32_t AlignInBits = 0);
  
      /// Identical to createGlobalVariable
      /// except that the resulting DbgNode is temporary and meant to be RAUWed.
      DIGlobalVariable *createTempGlobalVariableFwdDecl(
          DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
          unsigned LineNo, DIType *Ty, bool IsLocalToUnit, MDNode *Decl = nullptr,
          MDTuple *TemplateParams= nullptr, uint32_t AlignInBits = 0);
  
      /// Create a new descriptor for an auto variable.  This is a local variable
      /// that is not a subprogram parameter.
      ///
      /// \c Scope must be a \a DILocalScope, and thus its scope chain eventually
      /// leads to a \a DISubprogram.
      ///
      /// If \c AlwaysPreserve, this variable will be referenced from its
      /// containing subprogram, and will survive some optimizations.
      DILocalVariable *
      createAutoVariable(DIScope *Scope, StringRef Name, DIFile *File,
                         unsigned LineNo, DIType *Ty, bool AlwaysPreserve = false,
                         DINode::DIFlags Flags = DINode::FlagZero,
                         uint32_t AlignInBits = 0);
  
      /// Create a new descriptor for an label.
      ///
      /// \c Scope must be a \a DILocalScope, and thus its scope chain eventually
      /// leads to a \a DISubprogram.
      DILabel *
      createLabel(DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNo,
                  bool AlwaysPreserve = false);
  
      /// Create a new descriptor for a parameter variable.
      ///
      /// \c Scope must be a \a DILocalScope, and thus its scope chain eventually
      /// leads to a \a DISubprogram.
      ///
      /// \c ArgNo is the index (starting from \c 1) of this variable in the
      /// subprogram parameters.  \c ArgNo should not conflict with other
      /// parameters of the same subprogram.
      ///
      /// If \c AlwaysPreserve, this variable will be referenced from its
      /// containing subprogram, and will survive some optimizations.
      DILocalVariable *
      createParameterVariable(DIScope *Scope, StringRef Name, unsigned ArgNo,
                              DIFile *File, unsigned LineNo, DIType *Ty,
                              bool AlwaysPreserve = false,
                              DINode::DIFlags Flags = DINode::FlagZero);
  
      /// Create a new descriptor for the specified
      /// variable which has a complex address expression for its address.
      /// \param Addr        An array of complex address operations.
      DIExpression *createExpression(ArrayRef<uint64_t> Addr = None);
      DIExpression *createExpression(ArrayRef<int64_t> Addr);
  
      /// Create an expression for a variable that does not have an address, but
      /// does have a constant value.
      DIExpression *createConstantValueExpression(uint64_t Val) {
        return DIExpression::get(
            VMContext, {dwarf::DW_OP_constu, Val, dwarf::DW_OP_stack_value});
      }
  
      /// Create a new descriptor for the specified subprogram.
      /// See comments in DISubprogram* for descriptions of these fields.
      /// \param Scope         Function scope.
      /// \param Name          Function name.
      /// \param LinkageName   Mangled function name.
      /// \param File          File where this variable is defined.
      /// \param LineNo        Line number.
      /// \param Ty            Function type.
      /// \param ScopeLine     Set to the beginning of the scope this starts
      /// \param Flags         e.g. is this function prototyped or not.
      ///                      These flags are used to emit dwarf attributes.
      /// \param SPFlags       Additional flags specific to subprograms.
      /// \param TParams       Function template parameters.
      /// \param ThrownTypes   Exception types this function may throw.
      DISubprogram *
      createFunction(DIScope *Scope, StringRef Name, StringRef LinkageName,
                     DIFile *File, unsigned LineNo, DISubroutineType *Ty,
                     unsigned ScopeLine, DINode::DIFlags Flags = DINode::FlagZero,
                     DISubprogram::DISPFlags SPFlags = DISubprogram::SPFlagZero,
                     DITemplateParameterArray TParams = nullptr,
                     DISubprogram *Decl = nullptr,
                     DITypeArray ThrownTypes = nullptr);
  
      /// Identical to createFunction,
      /// except that the resulting DbgNode is meant to be RAUWed.
      DISubprogram *createTempFunctionFwdDecl(
          DIScope *Scope, StringRef Name, StringRef LinkageName, DIFile *File,
          unsigned LineNo, DISubroutineType *Ty, unsigned ScopeLine,
          DINode::DIFlags Flags = DINode::FlagZero,
          DISubprogram::DISPFlags SPFlags = DISubprogram::SPFlagZero,
          DITemplateParameterArray TParams = nullptr,
          DISubprogram *Decl = nullptr, DITypeArray ThrownTypes = nullptr);
  
      /// Create a new descriptor for the specified C++ method.
      /// See comments in \a DISubprogram* for descriptions of these fields.
      /// \param Scope         Function scope.
      /// \param Name          Function name.
      /// \param LinkageName   Mangled function name.
      /// \param File          File where this variable is defined.
      /// \param LineNo        Line number.
      /// \param Ty            Function type.
      /// \param VTableIndex   Index no of this method in virtual table, or -1u if
      ///                      unrepresentable.
      /// \param ThisAdjustment
      ///                      MS ABI-specific adjustment of 'this' that occurs
      ///                      in the prologue.
      /// \param VTableHolder  Type that holds vtable.
      /// \param Flags         e.g. is this function prototyped or not.
      ///                      This flags are used to emit dwarf attributes.
      /// \param SPFlags       Additional flags specific to subprograms.
      /// \param TParams       Function template parameters.
      /// \param ThrownTypes   Exception types this function may throw.
      DISubprogram *
      createMethod(DIScope *Scope, StringRef Name, StringRef LinkageName,
                   DIFile *File, unsigned LineNo, DISubroutineType *Ty,
                   unsigned VTableIndex = 0, int ThisAdjustment = 0,
                   DIType *VTableHolder = nullptr,
                   DINode::DIFlags Flags = DINode::FlagZero,
                   DISubprogram::DISPFlags SPFlags = DISubprogram::SPFlagZero,
                   DITemplateParameterArray TParams = nullptr,
                   DITypeArray ThrownTypes = nullptr);
  
      /// Create common block entry for a Fortran common block.
      /// \param Scope       Scope of this common block.
      /// \param decl        Global variable declaration.
      /// \param Name        The name of this common block.
      /// \param File        The file this common block is defined.
      /// \param LineNo      Line number.
      DICommonBlock *createCommonBlock(DIScope *Scope, DIGlobalVariable *decl,
                                       StringRef Name, DIFile *File,
                                       unsigned LineNo);
  
      /// This creates new descriptor for a namespace with the specified
      /// parent scope.
      /// \param Scope       Namespace scope
      /// \param Name        Name of this namespace
      /// \param ExportSymbols True for C++ inline namespaces.
      DINamespace *createNameSpace(DIScope *Scope, StringRef Name,
                                   bool ExportSymbols);
  
      /// This creates new descriptor for a module with the specified
      /// parent scope.
      /// \param Scope       Parent scope
      /// \param Name        Name of this module
      /// \param ConfigurationMacros
      ///                    A space-separated shell-quoted list of -D macro
      ///                    definitions as they would appear on a command line.
      /// \param IncludePath The path to the module map file.
      /// \param APINotesFile The path to an API notes file for this module.
      /// \param File        Source file of the module declaration. Used for
      ///                    Fortran modules.
      /// \param LineNo      Source line number of the  module declaration.
      ///                    Used for Fortran modules.
      DIModule *createModule(DIScope *Scope, StringRef Name,
                             StringRef ConfigurationMacros, StringRef IncludePath,
                             StringRef APINotesFile = {}, DIFile *File = nullptr,
                             unsigned LineNo = 0);
  
      /// This creates a descriptor for a lexical block with a new file
      /// attached. This merely extends the existing
      /// lexical block as it crosses a file.
      /// \param Scope       Lexical block.
      /// \param File        Source file.
      /// \param Discriminator DWARF path discriminator value.
      DILexicalBlockFile *createLexicalBlockFile(DIScope *Scope, DIFile *File,
                                                 unsigned Discriminator = 0);
  
      /// This creates a descriptor for a lexical block with the
      /// specified parent context.
      /// \param Scope         Parent lexical scope.
      /// \param File          Source file.
      /// \param Line          Line number.
      /// \param Col           Column number.
      DILexicalBlock *createLexicalBlock(DIScope *Scope, DIFile *File,
                                         unsigned Line, unsigned Col);
  
      /// Create a descriptor for an imported module.
      /// \param Context The scope this module is imported into
      /// \param NS      The namespace being imported here.
      /// \param File    File where the declaration is located.
      /// \param Line    Line number of the declaration.
      DIImportedEntity *createImportedModule(DIScope *Context, DINamespace *NS,
                                             DIFile *File, unsigned Line);
  
      /// Create a descriptor for an imported module.
      /// \param Context The scope this module is imported into.
      /// \param NS      An aliased namespace.
      /// \param File    File where the declaration is located.
      /// \param Line    Line number of the declaration.
      DIImportedEntity *createImportedModule(DIScope *Context,
                                             DIImportedEntity *NS, DIFile *File,
                                             unsigned Line);
  
      /// Create a descriptor for an imported module.
      /// \param Context The scope this module is imported into.
      /// \param M       The module being imported here
      /// \param File    File where the declaration is located.
      /// \param Line    Line number of the declaration.
      DIImportedEntity *createImportedModule(DIScope *Context, DIModule *M,
                                             DIFile *File, unsigned Line);
  
      /// Create a descriptor for an imported function.
      /// \param Context The scope this module is imported into.
      /// \param Decl    The declaration (or definition) of a function, type, or
      ///                variable.
      /// \param File    File where the declaration is located.
      /// \param Line    Line number of the declaration.
      DIImportedEntity *createImportedDeclaration(DIScope *Context, DINode *Decl,
                                                  DIFile *File, unsigned Line,
                                                  StringRef Name = "");
  
      /// Insert a new llvm.dbg.declare intrinsic call.
      /// \param Storage     llvm::Value of the variable
      /// \param VarInfo     Variable's debug info descriptor.
      /// \param Expr        A complex location expression.
      /// \param DL          Debug info location.
      /// \param InsertAtEnd Location for the new intrinsic.
      Instruction *insertDeclare(llvm::Value *Storage, DILocalVariable *VarInfo,
                                 DIExpression *Expr, const DILocation *DL,
                                 BasicBlock *InsertAtEnd);
  
      /// Insert a new llvm.dbg.declare intrinsic call.
      /// \param Storage      llvm::Value of the variable
      /// \param VarInfo      Variable's debug info descriptor.
      /// \param Expr         A complex location expression.
      /// \param DL           Debug info location.
      /// \param InsertBefore Location for the new intrinsic.
      Instruction *insertDeclare(llvm::Value *Storage, DILocalVariable *VarInfo,
                                 DIExpression *Expr, const DILocation *DL,
                                 Instruction *InsertBefore);
  
      /// Insert a new llvm.dbg.label intrinsic call.
      /// \param LabelInfo    Label's debug info descriptor.
      /// \param DL           Debug info location.
      /// \param InsertBefore Location for the new intrinsic.
      Instruction *insertLabel(DILabel *LabelInfo, const DILocation *DL,
                               Instruction *InsertBefore);
  
      /// Insert a new llvm.dbg.label intrinsic call.
      /// \param LabelInfo    Label's debug info descriptor.
      /// \param DL           Debug info location.
      /// \param InsertAtEnd Location for the new intrinsic.
      Instruction *insertLabel(DILabel *LabelInfo, const DILocation *DL,
                               BasicBlock *InsertAtEnd);
  
      /// Insert a new llvm.dbg.value intrinsic call.
      /// \param Val          llvm::Value of the variable
      /// \param VarInfo      Variable's debug info descriptor.
      /// \param Expr         A complex location expression.
      /// \param DL           Debug info location.
      /// \param InsertAtEnd Location for the new intrinsic.
      Instruction *insertDbgValueIntrinsic(llvm::Value *Val,
                                           DILocalVariable *VarInfo,
                                           DIExpression *Expr,
                                           const DILocation *DL,
                                           BasicBlock *InsertAtEnd);
  
      /// Insert a new llvm.dbg.value intrinsic call.
      /// \param Val          llvm::Value of the variable
      /// \param VarInfo      Variable's debug info descriptor.
      /// \param Expr         A complex location expression.
      /// \param DL           Debug info location.
      /// \param InsertBefore Location for the new intrinsic.
      Instruction *insertDbgValueIntrinsic(llvm::Value *Val,
                                           DILocalVariable *VarInfo,
                                           DIExpression *Expr,
                                           const DILocation *DL,
                                           Instruction *InsertBefore);
  
      /// Replace the vtable holder in the given type.
      ///
      /// If this creates a self reference, it may orphan some unresolved cycles
      /// in the operands of \c T, so \a DIBuilder needs to track that.
      void replaceVTableHolder(DICompositeType *&T,
                               DIType *VTableHolder);
  
      /// Replace arrays on a composite type.
      ///
      /// If \c T is resolved, but the arrays aren't -- which can happen if \c T
      /// has a self-reference -- \a DIBuilder needs to track the array to
      /// resolve cycles.
      void replaceArrays(DICompositeType *&T, DINodeArray Elements,
                         DINodeArray TParams = DINodeArray());
  
      /// Replace a temporary node.
      ///
      /// Call \a MDNode::replaceAllUsesWith() on \c N, replacing it with \c
      /// Replacement.
      ///
      /// If \c Replacement is the same as \c N.get(), instead call \a
      /// MDNode::replaceWithUniqued().  In this case, the uniqued node could
      /// have a different address, so we return the final address.
      template <class NodeTy>
      NodeTy *replaceTemporary(TempMDNode &&N, NodeTy *Replacement) {
        if (N.get() == Replacement)
          return cast<NodeTy>(MDNode::replaceWithUniqued(std::move(N)));
  
        N->replaceAllUsesWith(Replacement);
        return Replacement;
      }
    };
  
    // Create wrappers for C Binding types (see CBindingWrapping.h).
    DEFINE_ISA_CONVERSION_FUNCTIONS(DIBuilder, LLVMDIBuilderRef)
  
  } // end namespace llvm
  
  #endif // LLVM_IR_DIBUILDER_H
  