//===- MCDwarf.h - Machine Code Dwarf support -------------------*- 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 the declaration of the MCDwarfFile to support the dwarf

// .file directive and the .loc directive.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_MC_MCDWARF_H

#define LLVM_MC_MCDWARF_H

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/MapVector.h"

#include "llvm/ADT/StringMap.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/MC/MCSection.h"

#include "llvm/Support/Compiler.h"

#include "llvm/Support/Dwarf.h"

#include "llvm/Support/raw_ostream.h"

#include <map>

#include <string>

#include <utility>

#include <vector>

namespace llvm_ks {

class MCAsmBackend;

class MCContext;

class MCObjectStreamer;

class MCStreamer;

class MCSymbol;

class SourceMgr;

class SMLoc;

/// \brief Instances of this class represent the name of the dwarf

/// .file directive and its associated dwarf file number in the MC file,

/// and MCDwarfFile's are created and uniqued by the MCContext class where

/// the file number for each is its index into the vector of DwarfFiles (note

/// index 0 is not used and not a valid dwarf file number).

struct MCDwarfFile {

  // \brief The base name of the file without its directory path.

  // The StringRef references memory allocated in the MCContext.

  std::string Name;

  // \brief The index into the list of directory names for this file name.

  unsigned DirIndex;

};

/// \brief Instances of this class represent the information from a

/// dwarf .loc directive.

class MCDwarfLoc {

  uint32_t FileNum;

  uint32_t Line;

  uint16_t Column;

  // Flags (see #define's below)

  uint8_t Flags;

  uint8_t Isa;

  uint32_t Discriminator;

// Flag that indicates the initial value of the is_stmt_start flag.

#define DWARF2_LINE_DEFAULT_IS_STMT 1

#define DWARF2_FLAG_IS_STMT (1 << 0)

#define DWARF2_FLAG_BASIC_BLOCK (1 << 1)

#define DWARF2_FLAG_PROLOGUE_END (1 << 2)

#define DWARF2_FLAG_EPILOGUE_BEGIN (1 << 3)

private: // MCContext manages these

  friend class MCContext;

  friend class MCDwarfLineEntry;

  MCDwarfLoc(unsigned fileNum, unsigned line, unsigned column, unsigned flags,

             unsigned isa, unsigned discriminator)

      : FileNum(fileNum), Line(line), Column(column), Flags(flags), Isa(isa),

        Discriminator(discriminator) {}

  // Allow the default copy constructor and assignment operator to be used

  // for an MCDwarfLoc object.

public:

  /// \brief Get the FileNum of this MCDwarfLoc.

  unsigned getFileNum() const { return FileNum; }

  /// \brief Get the Line of this MCDwarfLoc.

  unsigned getLine() const { return Line; }

  /// \brief Get the Column of this MCDwarfLoc.

  unsigned getColumn() const { return Column; }

  /// \brief Get the Flags of this MCDwarfLoc.

  unsigned getFlags() const { return Flags; }

  /// \brief Get the Isa of this MCDwarfLoc.

  unsigned getIsa() const { return Isa; }

  /// \brief Get the Discriminator of this MCDwarfLoc.

  unsigned getDiscriminator() const { return Discriminator; }

  /// \brief Set the FileNum of this MCDwarfLoc.

  void setFileNum(unsigned fileNum) { FileNum = fileNum; }

  /// \brief Set the Line of this MCDwarfLoc.

  void setLine(unsigned line) { Line = line; }

  /// \brief Set the Column of this MCDwarfLoc.

  void setColumn(unsigned column) {

    assert(column <= UINT16_MAX);

    Column = column;

  }

  /// \brief Set the Flags of this MCDwarfLoc.

  void setFlags(unsigned flags) {

    assert(flags <= UINT8_MAX);

    Flags = flags;

  }

  /// \brief Set the Isa of this MCDwarfLoc.

  void setIsa(unsigned isa) {

    assert(isa <= UINT8_MAX);

    Isa = isa;

  }

  /// \brief Set the Discriminator of this MCDwarfLoc.

  void setDiscriminator(unsigned discriminator) {

    Discriminator = discriminator;

  }

};

/// \brief Instances of this class represent the line information for

/// the dwarf line table entries.  Which is created after a machine

/// instruction is assembled and uses an address from a temporary label

/// created at the current address in the current section and the info from

/// the last .loc directive seen as stored in the context.

class MCDwarfLineEntry : public MCDwarfLoc {

  MCSymbol *Label;

private:

  // Allow the default copy constructor and assignment operator to be used

  // for an MCDwarfLineEntry object.

public:

  // Constructor to create an MCDwarfLineEntry given a symbol and the dwarf loc.

  MCDwarfLineEntry(MCSymbol *label, const MCDwarfLoc loc)

      : MCDwarfLoc(loc), Label(label) {}

  MCSymbol *getLabel() const { return Label; }

  // This is called when an instruction is assembled into the specified

  // section and if there is information from the last .loc directive that

  // has yet to have a line entry made for it is made.

  static void Make(MCObjectStreamer *MCOS, MCSection *Section);

};

/// \brief Instances of this class represent the line information for a compile

/// unit where machine instructions have been assembled after seeing .loc

/// directives.  This is the information used to build the dwarf line

/// table for a section.

class MCLineSection {

public:

  // \brief Add an entry to this MCLineSection's line entries.

  void addLineEntry(const MCDwarfLineEntry &LineEntry, MCSection *Sec) {

    MCLineDivisions[Sec].push_back(LineEntry);

  }

  typedef std::vector<MCDwarfLineEntry> MCDwarfLineEntryCollection;

  typedef MCDwarfLineEntryCollection::iterator iterator;

  typedef MCDwarfLineEntryCollection::const_iterator const_iterator;

  typedef MapVector<MCSection *, MCDwarfLineEntryCollection> MCLineDivisionMap;

private:

  // A collection of MCDwarfLineEntry for each section.

  MCLineDivisionMap MCLineDivisions;

public:

  // Returns the collection of MCDwarfLineEntry for a given Compile Unit ID.

  const MCLineDivisionMap &getMCLineEntries() const {

    return MCLineDivisions;

  }

};

struct MCDwarfLineTableParams {

  /// First special line opcode - leave room for the standard opcodes.

  /// Note: If you want to change this, you'll have to update the

  /// "StandardOpcodeLengths" table that is emitted in

  /// \c Emit().

  uint8_t DWARF2LineOpcodeBase = 13;

  /// Minimum line offset in a special line info. opcode.  The value

  /// -5 was chosen to give a reasonable range of values.

  int8_t DWARF2LineBase = -5;

  /// Range of line offsets in a special line info. opcode.

  uint8_t DWARF2LineRange = 14;

};

struct MCDwarfLineTableHeader {

  MCSymbol *Label;

  SmallVector<std::string, 3> MCDwarfDirs;

  SmallVector<MCDwarfFile, 3> MCDwarfFiles;

  StringMap<unsigned> SourceIdMap;

  StringRef CompilationDir;

  MCDwarfLineTableHeader() : Label(nullptr) {}

  unsigned getFile(StringRef &Directory, StringRef &FileName,

                   unsigned FileNumber = 0);

  std::pair<MCSymbol *, MCSymbol *> Emit(MCStreamer *MCOS,

                                         MCDwarfLineTableParams Params) const;

  std::pair<MCSymbol *, MCSymbol *>

  Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,

       ArrayRef<char> SpecialOpcodeLengths) const;

};

class MCDwarfDwoLineTable {

  MCDwarfLineTableHeader Header;

public:

  void setCompilationDir(StringRef CompilationDir) {

    Header.CompilationDir = CompilationDir;

  }

  unsigned getFile(StringRef Directory, StringRef FileName) {

    return Header.getFile(Directory, FileName);

  }

  void Emit(MCStreamer &MCOS, MCDwarfLineTableParams Params) const;

};

class MCDwarfLineTable {

  MCDwarfLineTableHeader Header;

  MCLineSection MCLineSections;

public:

  // This emits the Dwarf file and the line tables for all Compile Units.

  static void Emit(MCObjectStreamer *MCOS, MCDwarfLineTableParams Params);

  // This emits the Dwarf file and the line tables for a given Compile Unit.

  void EmitCU(MCObjectStreamer *MCOS, MCDwarfLineTableParams Params) const;

  unsigned getFile(StringRef &Directory, StringRef &FileName,

                   unsigned FileNumber = 0);

  MCSymbol *getLabel() const {

    return Header.Label;

  }

  void setLabel(MCSymbol *Label) {

    Header.Label = Label;

  }

  void setCompilationDir(StringRef CompilationDir) {

    Header.CompilationDir = CompilationDir;

  }

  const SmallVectorImpl<std::string> &getMCDwarfDirs() const {

    return Header.MCDwarfDirs;

  }

  SmallVectorImpl<std::string> &getMCDwarfDirs() {

    return Header.MCDwarfDirs;

  }

  const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles() const {

    return Header.MCDwarfFiles;

  }

  SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles() {

    return Header.MCDwarfFiles;

  }

  const MCLineSection &getMCLineSections() const {

    return MCLineSections;

  }

  MCLineSection &getMCLineSections() {

    return MCLineSections;

  }

};

class MCDwarfLineAddr {

public:

  /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.

  static void Encode(MCContext &Context, MCDwarfLineTableParams Params,

                     int64_t LineDelta, uint64_t AddrDelta, raw_ostream &OS);

  /// Utility function to emit the encoding to a streamer.

  static void Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,

                   int64_t LineDelta, uint64_t AddrDelta);

};

class MCGenDwarfInfo {

public:

  //

  // When generating dwarf for assembly source files this emits the Dwarf

  // sections.

  //

  static void Emit(MCStreamer *MCOS);

};

// When generating dwarf for assembly source files this is the info that is

// needed to be gathered for each symbol that will have a dwarf label.

class MCGenDwarfLabelEntry {

private:

  // Name of the symbol without a leading underbar, if any.

  StringRef Name;

  // The dwarf file number this symbol is in.

  unsigned FileNumber;

  // The line number this symbol is at.

  unsigned LineNumber;

  // The low_pc for the dwarf label is taken from this symbol.

  MCSymbol *Label;

public:

  MCGenDwarfLabelEntry(StringRef name, unsigned fileNumber, unsigned lineNumber,

                       MCSymbol *label)

      : Name(name), FileNumber(fileNumber), LineNumber(lineNumber),

        Label(label) {}

  StringRef getName() const { return Name; }

  unsigned getFileNumber() const { return FileNumber; }

  unsigned getLineNumber() const { return LineNumber; }

  MCSymbol *getLabel() const { return Label; }

  // This is called when label is created when we are generating dwarf for

  // assembly source files.

  static void Make(MCSymbol *Symbol, MCStreamer *MCOS, SourceMgr &SrcMgr,

                   SMLoc &Loc);

};

class MCCFIInstruction {

public:

  enum OpType {

    OpSameValue,

    OpRememberState,

    OpRestoreState,

    OpOffset,

    OpDefCfaRegister,

    OpDefCfaOffset,

    OpDefCfa,

    OpRelOffset,

    OpAdjustCfaOffset,

    OpEscape,

    OpRestore,

    OpUndefined,

    OpRegister,

    OpWindowSave,

    OpGnuArgsSize

  };

private:

  OpType Operation;

  MCSymbol *Label;

  unsigned Register;

  union {

    int Offset;

    unsigned Register2;

  };

  std::vector<char> Values;

  MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R, int O, StringRef V)

      : Operation(Op), Label(L), Register(R), Offset(O),

        Values(V.begin(), V.end()) {

    assert(Op != OpRegister);

  }

  MCCFIInstruction(OpType Op, MCSymbol *L, unsigned R1, unsigned R2)

      : Operation(Op), Label(L), Register(R1), Register2(R2) {

    assert(Op == OpRegister);

  }

public:

  /// \brief .cfi_def_cfa defines a rule for computing CFA as: take address from

  /// Register and add Offset to it.

  static MCCFIInstruction createDefCfa(MCSymbol *L, unsigned Register,

                                       int Offset) {

    return MCCFIInstruction(OpDefCfa, L, Register, -Offset, "");

  }

  /// \brief .cfi_def_cfa_register modifies a rule for computing CFA. From now

  /// on Register will be used instead of the old one. Offset remains the same.

  static MCCFIInstruction createDefCfaRegister(MCSymbol *L, unsigned Register) {

    return MCCFIInstruction(OpDefCfaRegister, L, Register, 0, "");

  }

  /// \brief .cfi_def_cfa_offset modifies a rule for computing CFA. Register

  /// remains the same, but offset is new. Note that it is the absolute offset

  /// that will be added to a defined register to the compute CFA address.

  static MCCFIInstruction createDefCfaOffset(MCSymbol *L, int Offset) {

    return MCCFIInstruction(OpDefCfaOffset, L, 0, -Offset, "");

  }

  /// \brief .cfi_adjust_cfa_offset Same as .cfi_def_cfa_offset, but

  /// Offset is a relative value that is added/subtracted from the previous

  /// offset.

  static MCCFIInstruction createAdjustCfaOffset(MCSymbol *L, int Adjustment) {

    return MCCFIInstruction(OpAdjustCfaOffset, L, 0, Adjustment, "");

  }

  /// \brief .cfi_offset Previous value of Register is saved at offset Offset

  /// from CFA.

  static MCCFIInstruction createOffset(MCSymbol *L, unsigned Register,

                                       int Offset) {

    return MCCFIInstruction(OpOffset, L, Register, Offset, "");

  }

  /// \brief .cfi_rel_offset Previous value of Register is saved at offset

  /// Offset from the current CFA register. This is transformed to .cfi_offset

  /// using the known displacement of the CFA register from the CFA.

  static MCCFIInstruction createRelOffset(MCSymbol *L, unsigned Register,

                                          int Offset) {

    return MCCFIInstruction(OpRelOffset, L, Register, Offset, "");

  }

  /// \brief .cfi_register Previous value of Register1 is saved in

  /// register Register2.

  static MCCFIInstruction createRegister(MCSymbol *L, unsigned Register1,

                                         unsigned Register2) {

    return MCCFIInstruction(OpRegister, L, Register1, Register2);

  }

  /// \brief .cfi_window_save SPARC register window is saved.

  static MCCFIInstruction createWindowSave(MCSymbol *L) {

    return MCCFIInstruction(OpWindowSave, L, 0, 0, "");

  }

  /// \brief .cfi_restore says that the rule for Register is now the same as it

  /// was at the beginning of the function, after all initial instructions added

  /// by .cfi_startproc were executed.

  static MCCFIInstruction createRestore(MCSymbol *L, unsigned Register) {

    return MCCFIInstruction(OpRestore, L, Register, 0, "");

  }

  /// \brief .cfi_undefined From now on the previous value of Register can't be

  /// restored anymore.

  static MCCFIInstruction createUndefined(MCSymbol *L, unsigned Register) {

    return MCCFIInstruction(OpUndefined, L, Register, 0, "");

  }

  /// \brief .cfi_same_value Current value of Register is the same as in the

  /// previous frame. I.e., no restoration is needed.

  static MCCFIInstruction createSameValue(MCSymbol *L, unsigned Register) {

    return MCCFIInstruction(OpSameValue, L, Register, 0, "");

  }

  /// \brief .cfi_remember_state Save all current rules for all registers.

  static MCCFIInstruction createRememberState(MCSymbol *L) {

    return MCCFIInstruction(OpRememberState, L, 0, 0, "");

  }

  /// \brief .cfi_restore_state Restore the previously saved state.

  static MCCFIInstruction createRestoreState(MCSymbol *L) {

    return MCCFIInstruction(OpRestoreState, L, 0, 0, "");

  }

  /// \brief .cfi_escape Allows the user to add arbitrary bytes to the unwind

  /// info.

  static MCCFIInstruction createEscape(MCSymbol *L, StringRef Vals) {

    return MCCFIInstruction(OpEscape, L, 0, 0, Vals);

  }

  /// \brief A special wrapper for .cfi_escape that indicates GNU_ARGS_SIZE

  static MCCFIInstruction createGnuArgsSize(MCSymbol *L, int Size) {

    return MCCFIInstruction(OpGnuArgsSize, L, 0, Size, "");

  }

  OpType getOperation() const { return Operation; }

  MCSymbol *getLabel() const { return Label; }

  unsigned getRegister() const {

    assert(Operation == OpDefCfa || Operation == OpOffset ||

           Operation == OpRestore || Operation == OpUndefined ||

           Operation == OpSameValue || Operation == OpDefCfaRegister ||

           Operation == OpRelOffset || Operation == OpRegister);

    return Register;

  }

  unsigned getRegister2() const {

    assert(Operation == OpRegister);

    return Register2;

  }

  int getOffset() const {

    assert(Operation == OpDefCfa || Operation == OpOffset ||

           Operation == OpRelOffset || Operation == OpDefCfaOffset ||

           Operation == OpAdjustCfaOffset || Operation == OpGnuArgsSize);

    return Offset;

  }

  StringRef getValues() const {

    assert(Operation == OpEscape);

    return StringRef(&Values[0], Values.size());

  }

};

struct MCDwarfFrameInfo {

  MCDwarfFrameInfo()

      : Begin(nullptr), End(nullptr), Personality(nullptr), Lsda(nullptr),

        Instructions(), CurrentCfaRegister(0), PersonalityEncoding(),

        LsdaEncoding(0), CompactUnwindEncoding(0), IsSignalFrame(false),

        IsSimple(false) {}

  MCSymbol *Begin;

  MCSymbol *End;

  const MCSymbol *Personality;

  const MCSymbol *Lsda;

  std::vector<MCCFIInstruction> Instructions;

  unsigned CurrentCfaRegister;

  unsigned PersonalityEncoding;

  unsigned LsdaEncoding;

  uint32_t CompactUnwindEncoding;

  bool IsSignalFrame;

  bool IsSimple;

};

class MCDwarfFrameEmitter {

public:

  //

  // This emits the frame info section.

  //

  static void Emit(MCObjectStreamer &streamer, MCAsmBackend *MAB, bool isEH);

  static void EmitAdvanceLoc(MCObjectStreamer &Streamer, uint64_t AddrDelta);

  static void EncodeAdvanceLoc(MCContext &Context, uint64_t AddrDelta,

                               raw_ostream &OS);

};

} // end namespace llvm_ks

#endif