DIE.h   [plain text]

//===--- lib/CodeGen/DIE.h - DWARF Info Entries -----------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Data structures for DWARF info entries.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DIE_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_DIE_H

#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/ilist_node.h"
#include "llvm/ADT/ilist.h"
#include "llvm/Support/Dwarf.h"
#include <vector>

namespace llvm {
class AsmPrinter;
class MCExpr;
class MCSymbol;
class raw_ostream;
class DwarfTypeUnit;

class DIE;

template<>
struct ilist_traits<DIE> : public ilist_default_traits<DIE> {
  mutable ilist_half_node<DIE> Sentinel;

  DIE *createSentinel() const;
  void destroySentinel(DIE *) const {}

  DIE *provideInitialHead() const { return createSentinel(); }
  DIE *ensureHead(DIE*) const { return createSentinel(); }
  static void noteHead(DIE*, DIE*) {}
};

//===--------------------------------------------------------------------===//
/// DIEAbbrevData - Dwarf abbreviation data, describes one attribute of a
/// Dwarf abbreviation.
class DIEAbbrevData {
  /// Attribute - Dwarf attribute code.
  ///
  dwarf::Attribute Attribute;

  /// Form - Dwarf form code.
  ///
  dwarf::Form Form;

public:
  DIEAbbrevData(dwarf::Attribute A, dwarf::Form F) : Attribute(A), Form(F) {}

  // Accessors.
  dwarf::Attribute getAttribute() const { return Attribute; }
  dwarf::Form getForm() const { return Form; }

  /// Profile - Used to gather unique data for the abbreviation folding set.
  ///
  void Profile(FoldingSetNodeID &ID) const;
};

//===--------------------------------------------------------------------===//
/// DIEAbbrev - Dwarf abbreviation, describes the organization of a debug
/// information object.
class DIEAbbrev : public FoldingSetNode {
public:
  // Number of inline elements in the SmallVector containing the
  // AbbrevData elements. This needs to be the same as used inside DIE
  // for the DIEValue lists so that we do not leak memory (see
  // DIE::addValue()).
  static const unsigned NumInlineAttributes = 12;

private:
  /// Unique number for node.
  ///
  unsigned Number;

  /// Tag - Dwarf tag code.
  ///
  dwarf::Tag Tag;

  /// Children - Whether or not this node has children.
  ///
  // This cheats a bit in all of the uses since the values in the standard
  // are 0 and 1 for no children and children respectively.
  bool Children;

  /// Data - Raw data bytes for abbreviation.
  ///
  SmallVector<DIEAbbrevData, NumInlineAttributes> Data;

public:
  DIEAbbrev(dwarf::Tag T, bool C) : Tag(T), Children(C), Data() {}

  // Accessors.
  dwarf::Tag getTag() const { return Tag; }
  unsigned getNumber() const { return Number; }
  bool hasChildren() const { return Children; }
  const SmallVectorImpl<DIEAbbrevData> &getData() const { return Data; }
  void setChildrenFlag(bool hasChild) { Children = hasChild; }
  void setNumber(unsigned N) { Number = N; }

  /// AddAttribute - Adds another set of attribute information to the
  /// abbreviation.
  void AddAttribute(dwarf::Attribute Attribute, dwarf::Form Form) {
    Data.push_back(DIEAbbrevData(Attribute, Form));
  }

  /// Profile - Used to gather unique data for the abbreviation folding set.
  ///
  void Profile(FoldingSetNodeID &ID) const;

  /// Emit - Print the abbreviation using the specified asm printer.
  ///
  void Emit(const AsmPrinter *AP) const;

#ifndef NDEBUG
  void print(raw_ostream &O);
  void dump();
#endif
};

//===--------------------------------------------------------------------===//
/// DIE - A structured debug information entry.  Has an abbreviation which
/// describes its organization.
class DIEValue;

class DIE : public ilist_node<DIE> {
protected:
  /// Offset - Offset in debug info section.
  ///
  unsigned Offset;

  /// Size - Size of instance + children.
  ///
  unsigned Size;

  /// Abbrev - Buffer for constructing abbreviation.
  ///
  DIEAbbrev Abbrev;

  /// Children DIEs.
  ///
  // This can't be a vector<DIE> because pointer validity is requirent for the
  // Parent pointer and DIEEntry.
  // It can't be a list<DIE> because some clients need pointer validity before
  // the object has been added to any child list
  // (eg: DwarfUnit::constructVariableDIE). These aren't insurmountable, but may
  // be more convoluted than beneficial.
  ilist<DIE> Children;

  DIE *Parent;

  /// Attribute values.
  ///
  SmallVector<DIEValue *, DIEAbbrev::NumInlineAttributes> Values;

protected:
  DIE()
      : Offset(0), Size(0), Abbrev((dwarf::Tag)0, dwarf::DW_CHILDREN_no),
        Parent(nullptr) {}

public:
  explicit DIE(dwarf::Tag Tag)
      : Offset(0), Size(0), Abbrev((dwarf::Tag)Tag, dwarf::DW_CHILDREN_no),
        Parent(nullptr) {}

  // Accessors.
  DIEAbbrev &getAbbrev() { return Abbrev; }
  const DIEAbbrev &getAbbrev() const { return Abbrev; }
  unsigned getAbbrevNumber() const { return Abbrev.getNumber(); }
  dwarf::Tag getTag() const { return Abbrev.getTag(); }
  unsigned getOffset() const { return Offset; }
  unsigned getSize() const { return Size; }
  const ilist<DIE> &getChildren() const {
    return Children;
  }
  ilist<DIE> &getChildren() {
    return Children;
  }
  const SmallVectorImpl<DIEValue *> &getValues() const { return Values; }
  DIE *getParent() const { return Parent; }
  /// Climb up the parent chain to get the compile or type unit DIE this DIE
  /// belongs to.
  const DIE *getUnit() const;
  /// Similar to getUnit, returns null when DIE is not added to an
  /// owner yet.
  const DIE *getUnitOrNull() const;
  void setOffset(unsigned O) { Offset = O; }
  void setSize(unsigned S) { Size = S; }

  /// \brief Add a value and attributes to a DIE.
  ///
  /// \param DIEsToDelete If not null, the DIEs which contain
  /// SmallVectors that needed to allocate out-of-line storage for
  /// their elements are stored in this list. This allows to allocate
  /// everything DIE-related from a BumpPtrAllocator while still
  /// keeping track of the DIEs that need their destructors called so
  /// that we don't leak their external memory.
  void addValue(dwarf::Attribute Attribute, dwarf::Form Form, DIEValue *Value, std::vector<DIE *> *DIEsToDelete = nullptr) {
    Abbrev.AddAttribute(Attribute, Form);
    Values.push_back(Value);
    if (DIEsToDelete && Values.size() == DIEAbbrev::NumInlineAttributes + 1)
      DIEsToDelete->push_back(this);
  }

  /// addChild - Add a child to the DIE.
  ///
  void addChild(DIE* Child) {
    assert(!Child->getParent());
    Abbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes);
    Child->Parent = this;
    Children.push_back(std::move(Child));
  }

  /// findAttribute - Find a value in the DIE with the attribute given,
  /// returns NULL if no such attribute exists.
  DIEValue *findAttribute(dwarf::Attribute Attribute) const;

#ifndef NDEBUG
  void print(raw_ostream &O, unsigned IndentCount = 0) const;
  void dump();
#endif
};

inline DIE *
ilist_traits<DIE>::createSentinel() const {
  return static_cast<DIE*>(&Sentinel);
}

//===--------------------------------------------------------------------===//
/// DIEValue - A debug information entry value. Some of these roughly correlate
/// to DWARF attribute classes.
///
class DIEValue {
  virtual void anchor();

public:
  enum Type {
    isInteger,
    isString,
    isExpr,
    isLabel,
    isDelta,
    isEntry,
    isTypeSignature,
    isBlock,
    isLoc,
    isLocList,
  };

protected:
  /// Ty - Type of data stored in the value.
  ///
  Type Ty;

  explicit DIEValue(Type T) : Ty(T) {}
  virtual ~DIEValue() {}

public:
  // Accessors
  Type getType() const { return Ty; }

  /// EmitValue - Emit value via the Dwarf writer.
  ///
  virtual void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const = 0;

  /// SizeOf - Return the size of a value in bytes.
  ///
  virtual unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const = 0;

#ifndef NDEBUG
  virtual void print(raw_ostream &O) const = 0;
  void dump() const;
#endif
};

//===--------------------------------------------------------------------===//
/// DIEInteger - An integer value DIE.
///
class DIEInteger : public DIEValue {
  uint64_t Integer;

public:
  explicit DIEInteger(uint64_t I) : DIEValue(isInteger), Integer(I) {}

  /// BestForm - Choose the best form for integer.
  ///
  static dwarf::Form BestForm(bool IsSigned, uint64_t Int) {
    if (IsSigned) {
      const int64_t SignedInt = Int;
      if ((char)Int == SignedInt)
        return dwarf::DW_FORM_data1;
      if ((short)Int == SignedInt)
        return dwarf::DW_FORM_data2;
      if ((int)Int == SignedInt)
        return dwarf::DW_FORM_data4;
    } else {
      if ((unsigned char)Int == Int)
        return dwarf::DW_FORM_data1;
      if ((unsigned short)Int == Int)
        return dwarf::DW_FORM_data2;
      if ((unsigned int)Int == Int)
        return dwarf::DW_FORM_data4;
    }
    return dwarf::DW_FORM_data8;
  }

  /// EmitValue - Emit integer of appropriate size.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  uint64_t getValue() const { return Integer; }
  void setValue(uint64_t Val) { Integer = Val; }

  /// SizeOf - Determine size of integer value in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *I) { return I->getType() == isInteger; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// DIEExpr - An expression DIE.
//
class DIEExpr : public DIEValue {
  const MCExpr *Expr;

public:
  explicit DIEExpr(const MCExpr *E) : DIEValue(isExpr), Expr(E) {}

  /// EmitValue - Emit expression value.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// getValue - Get MCExpr.
  ///
  const MCExpr *getValue() const { return Expr; }

  /// SizeOf - Determine size of expression value in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *E) { return E->getType() == isExpr; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// DIELabel - A label DIE.
//
class DIELabel : public DIEValue {
  const MCSymbol *Label;

public:
  explicit DIELabel(const MCSymbol *L) : DIEValue(isLabel), Label(L) {}

  /// EmitValue - Emit label value.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// getValue - Get MCSymbol.
  ///
  const MCSymbol *getValue() const { return Label; }

  /// SizeOf - Determine size of label value in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *L) { return L->getType() == isLabel; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// DIEDelta - A simple label difference DIE.
///
class DIEDelta : public DIEValue {
  const MCSymbol *LabelHi;
  const MCSymbol *LabelLo;

public:
  DIEDelta(const MCSymbol *Hi, const MCSymbol *Lo)
      : DIEValue(isDelta), LabelHi(Hi), LabelLo(Lo) {}

  /// EmitValue - Emit delta value.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// SizeOf - Determine size of delta value in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *D) { return D->getType() == isDelta; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// DIEString - A container for string values.
///
class DIEString : public DIEValue {
  const DIEValue *Access;
  StringRef Str;

public:
  DIEString(const DIEValue *Acc, StringRef S)
      : DIEValue(isString), Access(Acc), Str(S) {}

  /// getString - Grab the string out of the object.
  StringRef getString() const { return Str; }

  /// EmitValue - Emit delta value.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// SizeOf - Determine size of delta value in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *D) { return D->getType() == isString; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// DIEEntry - A pointer to another debug information entry.  An instance of
/// this class can also be used as a proxy for a debug information entry not
/// yet defined (ie. types.)
class DIEEntry : public DIEValue {
  DIE &Entry;

public:
  explicit DIEEntry(DIE &E) : DIEValue(isEntry), Entry(E) {
  }

  DIE &getEntry() const { return Entry; }

  /// EmitValue - Emit debug information entry offset.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// SizeOf - Determine size of debug information entry in bytes.
  ///
   unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override {
    return Form == dwarf::DW_FORM_ref_addr ? getRefAddrSize(AP)
                                           : sizeof(int32_t);
  }

  /// Returns size of a ref_addr entry.
  static unsigned getRefAddrSize(const AsmPrinter *AP);

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *E) { return E->getType() == isEntry; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// \brief A signature reference to a type unit.
class DIETypeSignature : public DIEValue {
  const DwarfTypeUnit &Unit;

public:
  explicit DIETypeSignature(const DwarfTypeUnit &Unit)
      : DIEValue(isTypeSignature), Unit(Unit) {}

  /// \brief Emit type unit signature.
  void EmitValue(const AsmPrinter *Asm, dwarf::Form Form) const override;

  /// Returns size of a ref_sig8 entry.
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override {
    assert(Form == dwarf::DW_FORM_ref_sig8);
    return 8;
  }

  // \brief Implement isa/cast/dyncast.
  static bool classof(const DIEValue *E) {
    return E->getType() == isTypeSignature;
  }
#ifndef NDEBUG
  void print(raw_ostream &O) const override;
  void dump() const;
#endif
};

//===--------------------------------------------------------------------===//
/// DIELoc - Represents an expression location.
//
class DIELoc : public DIEValue, public DIE {
  mutable unsigned Size; // Size in bytes excluding size header.
public:
  DIELoc() : DIEValue(isLoc), Size(0) {}

  /// ComputeSize - Calculate the size of the location expression.
  ///
  unsigned ComputeSize(const AsmPrinter *AP) const;

  /// BestForm - Choose the best form for data.
  ///
  dwarf::Form BestForm(unsigned DwarfVersion) const {
    if (DwarfVersion > 3)
      return dwarf::DW_FORM_exprloc;
    // Pre-DWARF4 location expressions were blocks and not exprloc.
    if ((unsigned char)Size == Size)
      return dwarf::DW_FORM_block1;
    if ((unsigned short)Size == Size)
      return dwarf::DW_FORM_block2;
    if ((unsigned int)Size == Size)
      return dwarf::DW_FORM_block4;
    return dwarf::DW_FORM_block;
  }

  /// EmitValue - Emit location data.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// SizeOf - Determine size of location data in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *E) { return E->getType() == isLoc; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// DIEBlock - Represents a block of values.
//
class DIEBlock : public DIEValue, public DIE {
  mutable unsigned Size; // Size in bytes excluding size header.
public:
  DIEBlock() : DIEValue(isBlock), Size(0) {}

  /// ComputeSize - Calculate the size of the location expression.
  ///
  unsigned ComputeSize(const AsmPrinter *AP) const;

  /// BestForm - Choose the best form for data.
  ///
  dwarf::Form BestForm() const {
    if ((unsigned char)Size == Size)
      return dwarf::DW_FORM_block1;
    if ((unsigned short)Size == Size)
      return dwarf::DW_FORM_block2;
    if ((unsigned int)Size == Size)
      return dwarf::DW_FORM_block4;
    return dwarf::DW_FORM_block;
  }

  /// EmitValue - Emit location data.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// SizeOf - Determine size of location data in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *E) { return E->getType() == isBlock; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

//===--------------------------------------------------------------------===//
/// DIELocList - Represents a pointer to a location list in the debug_loc
/// section.
//
class DIELocList : public DIEValue {
  // Index into the .debug_loc vector.
  size_t Index;

public:
  DIELocList(size_t I) : DIEValue(isLocList), Index(I) {}

  /// getValue - Grab the current index out.
  size_t getValue() const { return Index; }

  /// EmitValue - Emit location data.
  ///
  void EmitValue(const AsmPrinter *AP, dwarf::Form Form) const override;

  /// SizeOf - Determine size of location data in bytes.
  ///
  unsigned SizeOf(const AsmPrinter *AP, dwarf::Form Form) const override;

  // Implement isa/cast/dyncast.
  static bool classof(const DIEValue *E) { return E->getType() == isLocList; }

#ifndef NDEBUG
  void print(raw_ostream &O) const override;
#endif
};

} // end llvm namespace

#endif