text: //===-- llvm/CodeGen/DwarfUnit.h - Dwarf Compile Unit ---*- C++ -*--===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file contains support for writing dwarf compile unit.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFUNIT_H
  #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFUNIT_H
  
  #include "DwarfDebug.h"
  #include "llvm/ADT/DenseMap.h"
  #include "llvm/ADT/Optional.h"
  #include "llvm/ADT/StringMap.h"
  #include "llvm/CodeGen/AsmPrinter.h"
  #include "llvm/CodeGen/DIE.h"
  #include "llvm/IR/DIBuilder.h"
  #include "llvm/IR/DebugInfo.h"
  #include "llvm/MC/MCDwarf.h"
  #include "llvm/MC/MCExpr.h"
  #include "llvm/MC/MCSection.h"
  
  namespace llvm {
  
  class MachineLocation;
  class MachineOperand;
  class ConstantInt;
  class ConstantFP;
  class DbgVariable;
  class DwarfCompileUnit;
  
  // Data structure to hold a range for range lists.
  class RangeSpan {
  public:
    RangeSpan(MCSymbol *S, MCSymbol *E) : Start(S), End(E) {}
    const MCSymbol *getStart() const { return Start; }
    const MCSymbol *getEnd() const { return End; }
    void setEnd(const MCSymbol *E) { End = E; }
  
  private:
    const MCSymbol *Start, *End;
  };
  
  class RangeSpanList {
  private:
    // Index for locating within the debug_range section this particular span.
    MCSymbol *RangeSym;
    // List of ranges.
    SmallVector<RangeSpan, 2> Ranges;
  
  public:
    RangeSpanList(MCSymbol *Sym, SmallVector<RangeSpan, 2> Ranges)
        : RangeSym(Sym), Ranges(std::move(Ranges)) {}
    MCSymbol *getSym() const { return RangeSym; }
    const SmallVectorImpl<RangeSpan> &getRanges() const { return Ranges; }
    void addRange(RangeSpan Range) { Ranges.push_back(Range); }
  };
  
  //===----------------------------------------------------------------------===//
  /// This dwarf writer support class manages information associated with a
  /// source file.
  class DwarfUnit {
  protected:
    /// A numeric ID unique among all CUs in the module
    unsigned UniqueID;
  
    /// MDNode for the compile unit.
    const DICompileUnit *CUNode;
  
    // All DIEValues are allocated through this allocator.
    BumpPtrAllocator DIEValueAllocator;
  
    /// Unit debug information entry.
    DIE &UnitDie;
  
    /// Offset of the UnitDie from beginning of debug info section.
    unsigned DebugInfoOffset;
  
    /// Target of Dwarf emission.
    AsmPrinter *Asm;
  
    // Holders for some common dwarf information.
    DwarfDebug *DD;
    DwarfFile *DU;
  
    /// An anonymous type for index type.  Owned by UnitDie.
    DIE *IndexTyDie;
  
    /// Tracks the mapping of unit level debug information variables to debug
    /// information entries.
    DenseMap<const MDNode *, DIE *> MDNodeToDieMap;
  
    /// A list of all the DIEBlocks in use.
    std::vector<DIEBlock *> DIEBlocks;
  
    /// A list of all the DIELocs in use.
    std::vector<DIELoc *> DIELocs;
  
    /// This map is used to keep track of subprogram DIEs that need
    /// DW_AT_containing_type attribute. This attribute points to a DIE that
    /// corresponds to the MDNode mapped with the subprogram DIE.
    DenseMap<DIE *, const DINode *> ContainingTypeMap;
  
    /// The section this unit will be emitted in.
    MCSection *Section;
  
    DwarfUnit(unsigned UID, dwarf::Tag, const DICompileUnit *CU, AsmPrinter *A,
              DwarfDebug *DW, DwarfFile *DWU);
  
    /// Add a string attribute data and value.
    ///
    /// This is guaranteed to be in the local string pool instead of indirected.
    void addLocalString(DIE &Die, dwarf::Attribute Attribute, StringRef Str);
  
    void addIndexedString(DIE &Die, dwarf::Attribute Attribute, StringRef Str);
  
    bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie);
  
  public:
    virtual ~DwarfUnit();
  
    void initSection(MCSection *Section);
  
    MCSection *getSection() const {
      assert(Section);
      return Section;
    }
  
    // Accessors.
    AsmPrinter* getAsmPrinter() const { return Asm; }
    unsigned getUniqueID() const { return UniqueID; }
    uint16_t getLanguage() const { return CUNode->getSourceLanguage(); }
    const DICompileUnit *getCUNode() const { return CUNode; }
    DIE &getUnitDie() { return UnitDie; }
  
    unsigned getDebugInfoOffset() const { return DebugInfoOffset; }
    void setDebugInfoOffset(unsigned DbgInfoOff) { DebugInfoOffset = DbgInfoOff; }
  
    /// Return true if this compile unit has something to write out.
    bool hasContent() const { return UnitDie.hasChildren(); }
  
    /// Get string containing language specific context for a global name.
    ///
    /// Walks the metadata parent chain in a language specific manner (using the
    /// compile unit language) and returns it as a string. This is done at the
    /// metadata level because DIEs may not currently have been added to the
    /// parent context and walking the DIEs looking for names is more expensive
    /// than walking the metadata.
    std::string getParentContextString(const DIScope *Context) const;
  
    /// Add a new global name to the compile unit.
    virtual void addGlobalName(StringRef Name, DIE &Die, const DIScope *Context) {
    }
  
    /// Add a new global type to the compile unit.
    virtual void addGlobalType(const DIType *Ty, const DIE &Die,
                               const DIScope *Context) {}
  
    /// Add a new name to the namespace accelerator table.
    void addAccelNamespace(StringRef Name, const DIE &Die);
  
    /// Returns the DIE map slot for the specified debug variable.
    ///
    /// We delegate the request to DwarfDebug when the MDNode can be part of the
    /// type system, since DIEs for the type system can be shared across CUs and
    /// the mappings are kept in DwarfDebug.
    DIE *getDIE(const DINode *D) const;
  
    /// Returns a fresh newly allocated DIELoc.
    DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; }
  
    /// Insert DIE into the map.
    ///
    /// We delegate the request to DwarfDebug when the MDNode can be part of the
    /// type system, since DIEs for the type system can be shared across CUs and
    /// the mappings are kept in DwarfDebug.
    void insertDIE(const DINode *Desc, DIE *D);
  
    /// Add a flag that is true to the DIE.
    void addFlag(DIE &Die, dwarf::Attribute Attribute);
  
    /// Add an unsigned integer attribute data and value.
    void addUInt(DIE &Die, dwarf::Attribute Attribute, Optional<dwarf::Form> Form,
                 uint64_t Integer);
  
    void addUInt(DIE &Block, dwarf::Form Form, uint64_t Integer);
  
    /// Add an signed integer attribute data and value.
    void addSInt(DIE &Die, dwarf::Attribute Attribute, Optional<dwarf::Form> Form,
                 int64_t Integer);
  
    void addSInt(DIELoc &Die, Optional<dwarf::Form> Form, int64_t Integer);
  
    /// Add a string attribute data and value.
    ///
    /// We always emit a reference to the string pool instead of immediate
    /// strings so that DIEs have more predictable sizes. In the case of split
    /// dwarf we emit an index into another table which gets us the static offset
    /// into the string table.
    void addString(DIE &Die, dwarf::Attribute Attribute, StringRef Str);
  
    /// Add a Dwarf label attribute data and value.
    DIE::value_iterator addLabel(DIE &Die, dwarf::Attribute Attribute,
                                 dwarf::Form Form, const MCSymbol *Label);
  
    void addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label);
  
    /// Add an offset into a section attribute data and value.
    void addSectionOffset(DIE &Die, dwarf::Attribute Attribute, uint64_t Integer);
  
    /// Add a dwarf op address data and value using the form given and an
    /// op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
    void addOpAddress(DIELoc &Die, const MCSymbol *Label);
  
    /// Add a label delta attribute data and value.
    void addLabelDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
                       const MCSymbol *Lo);
  
    /// Add a DIE attribute data and value.
    void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry);
  
    /// Add a DIE attribute data and value.
    void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry);
  
    void addDIETypeSignature(DIE &Die, const DwarfTypeUnit &Type);
  
    /// Add block data.
    void addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Block);
  
    /// Add block data.
    void addBlock(DIE &Die, dwarf::Attribute Attribute, DIEBlock *Block);
  
    /// Add location information to specified debug information entry.
    void addSourceLine(DIE &Die, unsigned Line, StringRef File,
                       StringRef Directory);
    void addSourceLine(DIE &Die, const DILocalVariable *V);
    void addSourceLine(DIE &Die, const DIGlobalVariable *G);
    void addSourceLine(DIE &Die, const DISubprogram *SP);
    void addSourceLine(DIE &Die, const DIType *Ty);
    void addSourceLine(DIE &Die, const DINamespace *NS);
    void addSourceLine(DIE &Die, const DIObjCProperty *Ty);
  
    /// Add constant value entry in variable DIE.
    void addConstantValue(DIE &Die, const MachineOperand &MO, const DIType *Ty);
    void addConstantValue(DIE &Die, const ConstantInt *CI, const DIType *Ty);
    void addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty);
    void addConstantValue(DIE &Die, const APInt &Val, bool Unsigned);
    void addConstantValue(DIE &Die, bool Unsigned, uint64_t Val);
  
    /// Add constant value entry in variable DIE.
    void addConstantFPValue(DIE &Die, const MachineOperand &MO);
    void addConstantFPValue(DIE &Die, const ConstantFP *CFP);
  
    /// Add a linkage name, if it isn't empty.
    void addLinkageName(DIE &Die, StringRef LinkageName);
  
    /// Add template parameters in buffer.
    void addTemplateParams(DIE &Buffer, DINodeArray TParams);
  
    /// Add register operand.
    /// \returns false if the register does not exist, e.g., because it was never
    /// materialized.
    bool addRegisterOpPiece(DIELoc &TheDie, unsigned Reg,
                            unsigned SizeInBits = 0, unsigned OffsetInBits = 0);
  
    /// Add register offset.
    /// \returns false if the register does not exist, e.g., because it was never
    /// materialized.
    bool addRegisterOffset(DIELoc &TheDie, unsigned Reg, int64_t Offset);
  
    // FIXME: Should be reformulated in terms of addComplexAddress.
    /// Start with the address based on the location provided, and generate the
    /// DWARF information necessary to find the actual Block variable (navigating
    /// the Block struct) based on the starting location.  Add the DWARF
    /// information to the die.  Obsolete, please use addComplexAddress instead.
    void addBlockByrefAddress(const DbgVariable &DV, DIE &Die,
                              dwarf::Attribute Attribute,
                              const MachineLocation &Location);
  
    /// Add a new type attribute to the specified entity.
    ///
    /// This takes and attribute parameter because DW_AT_friend attributes are
    /// also type references.
    void addType(DIE &Entity, const DIType *Ty,
                 dwarf::Attribute Attribute = dwarf::DW_AT_type);
  
    DIE *getOrCreateNameSpace(const DINamespace *NS);
    DIE *getOrCreateModule(const DIModule *M);
    DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal = false);
  
    void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
                                   bool Minimal = false);
  
    /// Find existing DIE or create new DIE for the given type.
    DIE *getOrCreateTypeDIE(const MDNode *N);
  
    /// Get context owner's DIE.
    DIE *createTypeDIE(const DICompositeType *Ty);
  
    /// Get context owner's DIE.
    DIE *getOrCreateContextDIE(const DIScope *Context);
  
    /// Construct DIEs for types that contain vtables.
    void constructContainingTypeDIEs();
  
    /// Construct function argument DIEs.
    void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args);
  
    /// Create a DIE with the given Tag, add the DIE to its parent, and
    /// call insertDIE if MD is not null.
    DIE &createAndAddDIE(unsigned Tag, DIE &Parent, const DINode *N = nullptr);
  
    /// Compute the size of a header for this unit, not including the initial
    /// length field.
    virtual unsigned getHeaderSize() const {
      return sizeof(int16_t) + // DWARF version number
             sizeof(int32_t) + // Offset Into Abbrev. Section
             sizeof(int8_t);   // Pointer Size (in bytes)
    }
  
    /// Emit the header for this unit, not including the initial length field.
    virtual void emitHeader(bool UseOffsets);
  
    virtual DwarfCompileUnit &getCU() = 0;
  
    void constructTypeDIE(DIE &Buffer, const DICompositeType *CTy);
  
  protected:
    /// Create new static data member DIE.
    DIE *getOrCreateStaticMemberDIE(const DIDerivedType *DT);
  
    /// Look up the source ID with the given directory and source file names. If
    /// none currently exists, create a new ID and insert it in the line table.
    virtual unsigned getOrCreateSourceID(StringRef File, StringRef Directory) = 0;
  
    /// Look in the DwarfDebug map for the MDNode that corresponds to the
    /// reference.
    template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
      return DD->resolve(Ref);
    }
  
  private:
    void constructTypeDIE(DIE &Buffer, const DIBasicType *BTy);
    void constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy);
    void constructTypeDIE(DIE &Buffer, const DISubroutineType *DTy);
    void constructSubrangeDIE(DIE &Buffer, const DISubrange *SR, DIE *IndexTy);
    void constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy);
    void constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy);
    void constructMemberDIE(DIE &Buffer, const DIDerivedType *DT);
    void constructTemplateTypeParameterDIE(DIE &Buffer,
                                           const DITemplateTypeParameter *TP);
    void constructTemplateValueParameterDIE(DIE &Buffer,
                                            const DITemplateValueParameter *TVP);
  
    /// Return the default lower bound for an array.
    ///
    /// If the DWARF version doesn't handle the language, return -1.
    int64_t getDefaultLowerBound() const;
  
    /// Get an anonymous type for index type.
    DIE *getIndexTyDie();
  
    /// Set D as anonymous type for index which can be reused later.
    void setIndexTyDie(DIE *D) { IndexTyDie = D; }
  
    /// If this is a named finished type then include it in the list of types for
    /// the accelerator tables.
    void updateAcceleratorTables(const DIScope *Context, const DIType *Ty,
                                 const DIE &TyDIE);
  
    virtual bool isDwoUnit() const = 0;
  };
  
  class DwarfTypeUnit : public DwarfUnit {
    uint64_t TypeSignature;
    const DIE *Ty;
    DwarfCompileUnit &CU;
    MCDwarfDwoLineTable *SplitLineTable;
  
    unsigned getOrCreateSourceID(StringRef File, StringRef Directory) override;
    bool isDwoUnit() const override;
  
  public:
    DwarfTypeUnit(unsigned UID, DwarfCompileUnit &CU, AsmPrinter *A,
                  DwarfDebug *DW, DwarfFile *DWU,
                  MCDwarfDwoLineTable *SplitLineTable = nullptr);
  
    void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; }
    uint64_t getTypeSignature() const { return TypeSignature; }
    void setType(const DIE *Ty) { this->Ty = Ty; }
  
    /// Emit the header for this unit, not including the initial length field.
    void emitHeader(bool UseOffsets) override;
    unsigned getHeaderSize() const override {
      return DwarfUnit::getHeaderSize() + sizeof(uint64_t) + // Type Signature
             sizeof(uint32_t);                               // Type DIE Offset
    }
    DwarfCompileUnit &getCU() override { return CU; }
  };
  } // end llvm namespace
  #endif
  