Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- MCWinEH.h - Windows Unwinding Support --------------------*- 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

//

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

#ifndef LLVM_MC_MCWINEH_H

#define LLVM_MC_MCWINEH_H

#include "llvm/ADT/MapVector.h"

#include <vector>

namespace llvm {

class MCSection;

class MCStreamer;

class MCSymbol;

namespace WinEH {

struct Instruction {

  const MCSymbol *Label;

  unsigned Offset;

  unsigned Register;

  unsigned Operation;

  Instruction(unsigned Op, MCSymbol *L, unsigned Reg, unsigned Off)

    : Label(L), Offset(Off), Register(Reg), Operation(Op) {}

  bool operator==(const Instruction &I) const {

    // Check whether two instructions refer to the same operation

    // applied at a different spot (i.e. pointing at a different label).

    return Offset == I.Offset && Register == I.Register &&

           Operation == I.Operation;

  }

  bool operator!=(const Instruction &I) const { return !(*this == I); }

};

struct FrameInfo {

  const MCSymbol *Begin = nullptr;

  const MCSymbol *End = nullptr;

  const MCSymbol *FuncletOrFuncEnd = nullptr;

  const MCSymbol *ExceptionHandler = nullptr;

  const MCSymbol *Function = nullptr;

  const MCSymbol *PrologEnd = nullptr;

  const MCSymbol *Symbol = nullptr;

  MCSection *TextSection = nullptr;

  uint32_t PackedInfo = 0;

  uint32_t PrologCodeBytes = 0;

  bool HandlesUnwind = false;

  bool HandlesExceptions = false;

  bool EmitAttempted = false;

  bool Fragment = false;

  int LastFrameInst = -1;

  const FrameInfo *ChainedParent = nullptr;

  std::vector<Instruction> Instructions;

  struct Epilog {

    std::vector<Instruction> Instructions;

    unsigned Condition;

    MCSymbol *End;

  };

  MapVector<MCSymbol *, Epilog> EpilogMap;

  // For splitting unwind info of large functions

  struct Segment {

    int64_t Offset;

    int64_t Length;

    bool HasProlog;

    MCSymbol *Symbol;

    // Map an Epilog's symbol to its offset within the function.

    MapVector<MCSymbol *, int64_t> Epilogs;

    Segment(int64_t Offset, int64_t Length, bool HasProlog = false)

        : Offset(Offset), Length(Length), HasProlog(HasProlog) {}

  };

  std::vector<Segment> Segments;

  FrameInfo() = default;

  FrameInfo(const MCSymbol *Function, const MCSymbol *BeginFuncEHLabel)

      : Begin(BeginFuncEHLabel), Function(Function) {}

  FrameInfo(const MCSymbol *Function, const MCSymbol *BeginFuncEHLabel,

            const FrameInfo *ChainedParent)

      : Begin(BeginFuncEHLabel), Function(Function),

        ChainedParent(ChainedParent) {}

  bool empty() const {

    if (!Instructions.empty())

      return false;

    for (const auto &E : EpilogMap)

      if (!E.second.Instructions.empty())

        return false;

    return true;

  }

};

class UnwindEmitter {

public:

  virtual ~UnwindEmitter();

  /// This emits the unwind info sections (.pdata and .xdata in PE/COFF).

  virtual void Emit(MCStreamer &Streamer) const = 0;

  virtual void EmitUnwindInfo(MCStreamer &Streamer, FrameInfo *FI,

                              bool HandlerData) const = 0;

};

}

}

#endif