binutils-gdb/gdb/trad-frame.h

/* Traditional frame unwind support, for GDB the GNU Debugger.

   Copyright (C) 2003-2021 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef TRAD_FRAME_H
#define TRAD_FRAME_H

#include "frame.h"		/* For "struct frame_id".  */

struct frame_info;
struct regcache_map_entry;
struct trad_frame_cache;

/* A simple, or traditional frame cache.

   The entire cache is populated in a single pass and then generic
   routines are used to extract the various cache values.  */

struct trad_frame_cache *trad_frame_cache_zalloc (struct frame_info *);

/* This frame's ID.  */
void trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
			struct frame_id this_id);
void trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
			struct frame_id *this_id);
void trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
			       CORE_ADDR this_base);
CORE_ADDR trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache);

void trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
				 int regnum, int realreg);
void trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
			      int regnum, CORE_ADDR addr);
void trad_frame_set_reg_regmap (struct trad_frame_cache *this_trad_cache,
				const struct regcache_map_entry *regmap,
				CORE_ADDR addr, size_t size);
void trad_frame_set_reg_value (struct trad_frame_cache *this_cache,
			       int regnum, LONGEST val);

/* Given the cache in THIS_TRAD_CACHE, set the value of REGNUM to the bytes
   contained in BYTES with size SIZE.  */
void trad_frame_set_reg_value_bytes (struct trad_frame_cache *this_trad_cache,
				     int regnum, const gdb_byte *bytes,
				     size_t size);

struct value *trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
				       struct frame_info *this_frame,
				       int regnum);

/* Describes the kind of encoding a stored register has.  */
enum class trad_frame_saved_reg_kind
{
  /* Register value is unknown.  */
  UNKNOWN = 0,
  /* Register value is a constant.  */
  VALUE,
  /* Register value is in another register.  */
  REALREG,
  /* Register value is at an address.  */
  ADDR,
  /* Register value is a sequence of bytes.  */
  VALUE_BYTES
};

/* A struct that describes a saved register in a frame.  */

struct trad_frame_saved_reg
{
  /* Setters */

  /* Encode that the saved register's value is constant VAL in the
     trad-frame.  */
  void set_value (LONGEST val)
  {
    m_kind = trad_frame_saved_reg_kind::VALUE;
    m_reg.value = val;
  }

  /* Encode that the saved register's value is stored in register REALREG.  */
  void set_realreg (int realreg)
  {
    m_kind = trad_frame_saved_reg_kind::REALREG;
    m_reg.realreg = realreg;
  }

  /* Encode that the saved register's value is stored in memory at ADDR.  */
  void set_addr (LONGEST addr)
  {
    m_kind = trad_frame_saved_reg_kind::ADDR;
    m_reg.addr = addr;
  }

  /* Encode that the saved register's value is unknown.  */
  void set_unknown ()
  {
    m_kind = trad_frame_saved_reg_kind::UNKNOWN;
  }

  /* Encode that the saved register's value is stored as a sequence of bytes.
     This is useful when the value is larger than what primitive types
     can hold.  */
  void set_value_bytes (const gdb_byte *value_bytes)
  {
    m_kind = trad_frame_saved_reg_kind::VALUE_BYTES;
    m_reg.value_bytes = value_bytes;
  }

  /* Getters */

  LONGEST value () const
  {
    gdb_assert (m_kind == trad_frame_saved_reg_kind::VALUE);
    return m_reg.value;
  }

  int realreg () const
  {
    gdb_assert (m_kind == trad_frame_saved_reg_kind::REALREG);
    return m_reg.realreg;
  }

  LONGEST addr () const
  {
    gdb_assert (m_kind == trad_frame_saved_reg_kind::ADDR);
    return m_reg.addr;
  }

  const gdb_byte *value_bytes () const
  {
    gdb_assert (m_kind == trad_frame_saved_reg_kind::VALUE_BYTES);
    return m_reg.value_bytes;
  }

  /* Convenience functions, return true if the register has been
     encoded as specified.  Return false otherwise.  */
  bool is_value () const
  {
    return m_kind == trad_frame_saved_reg_kind::VALUE;
  }

  bool is_realreg () const
  {
    return m_kind == trad_frame_saved_reg_kind::REALREG;
  }

  bool is_addr () const
  {
    return m_kind == trad_frame_saved_reg_kind::ADDR;
  }

  bool is_unknown () const
  {
    return m_kind == trad_frame_saved_reg_kind::UNKNOWN;
  }

  bool is_value_bytes () const
  {
    return m_kind == trad_frame_saved_reg_kind::VALUE_BYTES;
  }

private:

  trad_frame_saved_reg_kind m_kind;

  union {
    LONGEST value;
    int realreg;
    LONGEST addr;
    const gdb_byte *value_bytes;
  } m_reg;
};

/* Encode REGNUM value in the trad-frame.  */
void trad_frame_set_value (trad_frame_saved_reg this_saved_regs[],
			   int regnum, LONGEST val);

/* Encode REGNUM is in REALREG in the trad-frame.  */
void trad_frame_set_realreg (trad_frame_saved_reg this_saved_regs[],
			     int regnum, int realreg);

/* Encode REGNUM is at address ADDR in the trad-frame.  */
void trad_frame_set_addr (trad_frame_saved_reg this_trad_cache[],
			  int regnum, CORE_ADDR addr);

/* Mark REGNUM as unknown.  */
void trad_frame_set_unknown (trad_frame_saved_reg this_saved_regs[],
			     int regnum);

/* Encode REGNUM value in the trad-frame as a sequence of bytes.  This is
   useful when the value is larger than what primitive types can hold.  */
void trad_frame_set_value_bytes (trad_frame_saved_reg this_saved_regs[],
				 int regnum, const gdb_byte *bytes,
				 size_t size);

/* Convenience functions, return non-zero if the register has been
   encoded as specified.  */
int trad_frame_value_p (trad_frame_saved_reg this_saved_regs[],
			int regnum);
int trad_frame_addr_p (trad_frame_saved_reg this_saved_regs[],
		       int regnum);
int trad_frame_realreg_p (trad_frame_saved_reg this_saved_regs[],
			  int regnum);

/* Return TRUE if REGNUM is stored as a sequence of bytes, and FALSE
   otherwise.  */
bool trad_frame_value_bytes_p (trad_frame_saved_reg this_saved_regs[],
			      int regnum);

/* Reset the saved regs cache, setting register values to -1.  */
void trad_frame_reset_saved_regs (struct gdbarch *gdbarch,
				  trad_frame_saved_reg *regs);

/* Return a freshly allocated (and initialized) trad_frame array.  */
trad_frame_saved_reg *trad_frame_alloc_saved_regs (struct frame_info *);
trad_frame_saved_reg *trad_frame_alloc_saved_regs (struct gdbarch *);

/* Given the trad_frame info, return the location of the specified
   register.  */
struct value *trad_frame_get_prev_register (struct frame_info *this_frame,
					    trad_frame_saved_reg this_saved_regs[],
					    int regnum);

#endif