btrace, linux: add perf event buffer abstraction

[deliverable/binutils-gdb.git] / gdb / common / btrace-common.h

/* Branch trace support for GDB, the GNU debugger.

   Copyright (C) 2013-2015 Free Software Foundation, Inc.

   Contributed by Intel Corp. <markus.t.metzger@intel.com>.

   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 BTRACE_COMMON_H
#define BTRACE_COMMON_H

/* Branch tracing (btrace) is a per-thread control-flow execution trace of the
   inferior.  For presentation purposes, the branch trace is represented as a
   list of sequential control-flow blocks, one such list per thread.  */

#include "vec.h"

/* A branch trace block.

   This represents a block of sequential control-flow.  Adjacent blocks will be
   connected via calls, returns, or jumps.  The latter can be direct or
   indirect, conditional or unconditional.  Branches can further be
   asynchronous, e.g. interrupts.  */
struct btrace_block
{
  /* The address of the first byte of the first instruction in the block.
     The address may be zero if we do not know the beginning of this block,
     such as for the first block in a delta trace.  */
  CORE_ADDR begin;

  /* The address of the first byte of the last instruction in the block.  */
  CORE_ADDR end;
};

/* Define functions operating on a vector of branch trace blocks.  */
typedef struct btrace_block btrace_block_s;
DEF_VEC_O (btrace_block_s);

/* Enumeration of btrace formats.  */

enum btrace_format
{
  /* No branch trace format.  */
  BTRACE_FORMAT_NONE,

  /* Branch trace is in Branch Trace Store (BTS) format.
     Actually, the format is a sequence of blocks derived from BTS.  */
  BTRACE_FORMAT_BTS
};

/* Branch trace in BTS format.  */
struct btrace_data_bts
{
  /* Branch trace is represented as a vector of branch trace blocks starting
     with the most recent block.  */
  VEC (btrace_block_s) *blocks;
};

/* The branch trace data.  */
struct btrace_data
{
  enum btrace_format format;

  union
  {
    /* Format == BTRACE_FORMAT_BTS.  */
    struct btrace_data_bts bts;
  } variant;
};

/* Target specific branch trace information.  */
struct btrace_target_info;

/* Enumeration of btrace read types.  */

enum btrace_read_type
{
  /* Send all available trace.  */
  BTRACE_READ_ALL,

  /* Send all available trace, if it changed.  */
  BTRACE_READ_NEW,

  /* Send the trace since the last request.  This will fail if the trace
     buffer overflowed.  */
  BTRACE_READ_DELTA
};

/* Enumeration of btrace errors.  */

enum btrace_error
{
  /* No error.  Everything is OK.  */
  BTRACE_ERR_NONE,

  /* An unknown error.  */
  BTRACE_ERR_UNKNOWN,

  /* Branch tracing is not supported on this system.  */
  BTRACE_ERR_NOT_SUPPORTED,

  /* The branch trace buffer overflowed; no delta read possible.  */
  BTRACE_ERR_OVERFLOW
};

/* Return a string representation of FORMAT.  */
extern const char *btrace_format_string (enum btrace_format format);

/* Initialize DATA.  */
extern void btrace_data_init (struct btrace_data *data);

/* Cleanup DATA.  */
extern void btrace_data_fini (struct btrace_data *data);

/* Return non-zero if DATA is empty; zero otherwise.  */
extern int btrace_data_empty (struct btrace_data *data);

#endif /* BTRACE_COMMON_H */