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[official-gcc.git] / gcc / gcov-io.h

/* File format for coverage information
   Copyright (C) 1996, 1997, 1998, 2000, 2002 Free Software Foundation, Inc.
   Contributed by Bob Manson <manson@cygnus.com>.
   Completely remangled by Nathan Sidwell <nathan@codesourcery.com>.

This file is part of GCC.

GCC 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 2, or (at your option) any later
version.

GCC 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 GCC; see the file COPYING.  If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

/* Coverage information is held in two files.  A basic block graph
   file, which is generated by the compiler, and a counter file, which
   is generated by the program under test.  Both files use a similar
   structure.  We do not attempt to make these files backwards
   compatible with previous versions, as you only need coverage
   information when developing a program.  We do hold version
   information, so that mismatches can be detected, and we use a
   format that allows tools to skip information they do not understand
   or are not interested in.

   Numbers are recorded in big endian unsigned binary form.  Either in
   32 or 64 bits.  Strings are stored with a length count and NUL
   terminator, and 0 to 3 bytes of zero padding up to the next 4 byte
   boundary.  Zero length and NULL strings are simply stored as a
   length of zero (they have no trailing NUL or padding).

        int32:  byte3 byte2 byte1 byte0
        int64:  byte7 byte6 byte5 byte4 byte3 byte2 byte1 byte0
        string: int32:0 | int32:length char* char:0 padding
        padding: | char:0 | char:0 char:0 | char:0 char:0 char:0
        item: int32 | int64 | string

   The basic format of the files is

        file : int32:magic int32:version record*

   The magic ident is different for the bbg and the counter files.
   The version is the same for both files and is derived from gcc's
   version number.  Although the ident and version are formally 32 bit
   numbers, they are derived from 4 character ASCII strings.  The
   version number consists of the single character major version
   number, a two character minor version number (leading zero for
   versions less than 10), and a single character indicating the
   status of the release.  That will be 'e' experimental, 'p'
   prerelease and 'r' for release.  Because, by good fortune, these are
   in alphabetical order, string collating can be used to compare
   version strings, and because numbers are stored big endian, numeric
   comparison can be used when it is read as a 32 bit value.  Be aware
   that the 'e' designation will (naturally) be unstable and might be
   incompatible with itself.  For gcc 3.4 experimental, it would be
   '304e' (0x33303465).  When the major version reaches 10, the letters
   A-Z will be used.  Assuming minor increments releases every 6
   months, we have to make a major increment every 50 years.  Assuming
   major increments releases every 5 years, we're ok for the next 155
   years -- good enough for me.

   A record has a tag, length and variable amount of data.

        record: header data
        header: int32:tag int32:length
        data: item*

   Records are not nested, but there is a record hierarchy.  Tag
   numbers reflect this hierarchy.  Tags are unique across bbg and da
   files.  Some record types have a varying amount of data.  The LENGTH
   is usually used to determine how much data.  The tag value is split
   into 4 8-bit fields, one for each of four possible levels.  The
   most significant is allocated first.  Unused levels are zero.
   Active levels are odd-valued, so that the LSB of the level is one.
   A sub-level incorporates the values of its superlevels.  This
   formatting allows you to determine the tag heirarchy, without
   understanding the tags themselves, and is similar to the standard
   section numbering used in technical documents.  Level values
   [1..3f] are used for common tags, values [41..9f] for the graph
   file and [a1..ff] for the counter file.

   The basic block graph file contains the following records
        bbg:  function-graph*
        function-graph: announce_function basic_blocks {arcs | lines}*
        announce_function: header string:name int32:checksum
                string:source int32:lineno
        basic_block: header int32:flags*
        arcs: header int32:block_no arc*
        arc:  int32:dest_block int32:flags
        lines: header int32:block_no line*
               int32:0 string:NULL
        line:  int32:line_no | int32:0 string:filename

   The BASIC_BLOCK record holds per-bb flags.  The number of blocks
   can be inferred from its data length.  There is one ARCS record per
   basic block.  The number of arcs from a bb is implicit from the
   data length.  It enumerates the destination bb and per-arc flags.
   There is one LINES record per basic block, it enumerates the source
   lines which belong to that basic block.  Source file names are
   introduced by a line number of 0, following lines are from the new
   source file.  The initial source file for the function is NULL, but
   the current source file should be remembered from one LINES record
   to the next.  The end of a block is indicated by an empty filename
   - this does not reset the current source file.  Note there is no
   ordering of the ARCS and LINES records: they may be in any order,
   interleaved in any manner.  The current filename follows the order
   the LINES records are stored in the file, *not* the ordering of the
   blocks they are for.

   The data file contains the following records.
        da:   {function-data* summary:object summary:program*}*
        function-data:  announce_function arc_counts
        announce_function: header string:name int32:checksum
        arc_counts: header int64:count*
        summary: in32:checksum int32:runs int32:arcs int64:sum int64:max \
                int64:max_sum int64:sum_max

   The ANNOUNCE_FUNCTION record is the same as that in the BBG file,
   but without the source location.
   The ARC_COUNTS gives the counter values for those arcs that are
   instrumented.  The SUMMARY records give information about the whole
   object file and about the whole program.  The checksum is used for
   whole program summaries, and disambiguates different programs which
   include the same instrumented object file.  There may be several
   program summaries, each with a unique checksum.  The object
   summary's checkum is zero.  Note that the da file might contain
   information from several runs concatenated, or the data might be
   merged.

   This file is included by both the compiler, gcov tools and the
   runtime support library libgcov. IN_LIBGCOV and IN_GCOV are used to
   distinguish which case is which.  If IN_LIBGCOV is non-zero,
   libgcov is being built. If IN_GCOV is non-zero, the gcov tools are
   being built. Otherwise the compiler is being built. IN_GCOV may be
   positive or negative. If positive, we are compiling a tool that
   requires additional functions (see the code for knowledge of what
   those functions are).  */

#ifndef GCC_GCOV_IO_H
#define GCC_GCOV_IO_H

#if IN_LIBGCOV
#if LONG_TYPE_SIZE == GCOV_TYPE_SIZE
typedef long gcov_type;
#else
typedef long long gcov_type;
#endif
#endif /* IN_LIBGCOV */
#if IN_GCOV
typedef HOST_WIDEST_INT gcov_type;
#if IN_GCOV > 0
#include <sys/types.h>
#endif
#endif

/* File suffixes.  */
#define GCOV_DATA_SUFFIX ".da"
#define GCOV_GRAPH_SUFFIX ".bbg"

/* File magic.  */
#define GCOV_DATA_MAGIC  0x67636f76 /* "gcov" */
#define GCOV_GRAPH_MAGIC 0x67626267 /* "gbbg" */

/* gcov-iov.h is automatically generated by the makefile from
   version.c, it looks like
        #define GCOV_VERSION ((unsigned)0x89abcdef)
*/
#include "gcov-iov.h"

/* The record tags.  Values [1..3f] are for tags which may be in either
   file.  Values [41..9f] for those in the bbg file and [a1..ff] for
   the data file.  */

#define GCOV_TAG_FUNCTION        ((unsigned)0x01000000)
#define GCOV_TAG_BLOCKS          ((unsigned)0x01410000)
#define GCOV_TAG_ARCS            ((unsigned)0x01430000)
#define GCOV_TAG_LINES           ((unsigned)0x01450000)
#define GCOV_TAG_ARC_COUNTS      ((unsigned)0x01a10000)
#define GCOV_TAG_OBJECT_SUMMARY  ((unsigned)0xa1000000)
#define GCOV_TAG_PROGRAM_SUMMARY ((unsigned)0xa3000000)
#define GCOV_TAG_PLACEHOLDER_SUMMARY ((unsigned)0xa5000000)
#define GCOV_TAG_INCORRECT_SUMMARY ((unsigned)0xa7000000)

/* The tag level mask has 1's in the position of the inner levels, &
   the lsb of the current level, and zero on the current and outer
   levels.  */
#define GCOV_TAG_MASK(TAG) (((TAG) - 1) ^ (TAG))

/* Return nonzero if SUB is an immediate subtag of TAG.  */
#define GCOV_TAG_IS_SUBTAG(TAG,SUB)                             \
        (GCOV_TAG_MASK (TAG) >> 8 == GCOV_TAG_MASK (SUB)        \
         && !(((SUB) ^ (TAG)) & ~GCOV_TAG_MASK(TAG)))

/* Return nonzero if SUB is at a sublevel to TAG.  */
#define GCOV_TAG_IS_SUBLEVEL(TAG,SUB)                           \
        (GCOV_TAG_MASK (TAG) > GCOV_TAG_MASK (SUB))

/* Basic block flags.  */
#define GCOV_BLOCK_UNEXPECTED   (1 << 1)

/* Arc flags.  */
#define GCOV_ARC_ON_TREE        (1 << 0)
#define GCOV_ARC_FAKE           (1 << 1)
#define GCOV_ARC_FALLTHROUGH    (1 << 2)

/* Structured records.  */

/* Object & program summary record.  */
struct gcov_summary
{
  unsigned checksum;      /* checksum of program */
  unsigned runs;          /* number of program runs */
  unsigned arcs;          /* number of instrumented arcs */
  gcov_type arc_sum;      /* sum of all arc counters */
  gcov_type arc_max_one;  /* max counter on any one run */
  gcov_type arc_max_sum;  /* maximum arc_sum */
  gcov_type arc_sum_max;  /* sum of max_one */
};

/* Structures embedded in coveraged program.  The structures generated
   by write_profile must match these.  */

/* Information about section of counters for a function.  */
struct counter_section
{
  unsigned tag;         /* Tag of the section.  */
  unsigned n_counters;  /* Number of counters in the section.  */
};

#if IN_LIBGCOV
/* Information about section of counters for an object file.  */
struct counter_section_data
{
  unsigned tag;         /* Tag of the section.  */
  unsigned n_counters;  /* Number of counters in the section.  */
  gcov_type *counters;  /* The data.  */
};

/* Information about a single function.  */
struct function_info
{
  const char *name;             /* (mangled) name of function */
  unsigned checksum;            /* function checksum */
  unsigned n_counter_sections;  /* Number of types of counters */
  const struct counter_section *counter_sections;
                                /* The section descriptions */
};

/* Information about a single object file.  */
struct gcov_info
{
  unsigned long version;        /* expected version number */
  struct gcov_info *next;       /* link to next, used by libgcc */

  const char *filename;         /* output file name */
  long wkspc;                   /* libgcc workspace */

  unsigned n_functions;             /* number of functions */
  const struct function_info *functions; /* table of functions */

  unsigned n_counter_sections;  /* Number of types of counters */
  const struct counter_section_data *counter_sections;
                                /* The data to be put into the sections.  */
};

/* Register a new object file module.  */
extern void __gcov_init (struct gcov_info *);

/* Called before fork, to avoid double counting.  */
extern void __gcov_flush (void);

/* Since this file is used in both host and target files, and we don't
   include ansidecl.h in target files, provide some necessary macros.  */
#ifndef ATTRIBUTE_UNUSED
# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
#endif

#endif /* IN_LIBGCOV */

/* Because small reads and writes, interspersed with seeks cause lots
   of disk activity, we buffer the entire count files.  */

static struct gcov_var
{
  FILE *file;
  size_t position;
  size_t length;
  size_t alloc;
  unsigned modified;
  int error;
  unsigned char *buffer;
} gcov_var;

/* Functions for reading and writing gcov files.  */
static int gcov_open (const char */*name*/, int /*truncate*/);
static int gcov_close (void);
#if !IN_GCOV
static unsigned char *gcov_write_bytes (unsigned);
static void gcov_write_unsigned (unsigned);
#if IN_LIBGCOV
static void gcov_write_counter (gcov_type);
#endif
static void gcov_write_string (const char *);
static unsigned long gcov_write_tag (unsigned);
static void gcov_write_length (unsigned long /*position*/);
#if IN_LIBGCOV
static void gcov_write_summary (unsigned, const struct gcov_summary *);
#endif
#endif /* !IN_GCOV */
static const unsigned char *gcov_read_bytes (unsigned);
static unsigned gcov_read_unsigned (void);
static gcov_type gcov_read_counter (void);
static const char *gcov_read_string (void);
static void gcov_read_summary (struct gcov_summary *);

static unsigned long gcov_position (void);
static void gcov_seek (unsigned long /*base*/, unsigned /*length */);
static unsigned long gcov_seek_end (void);
static int gcov_is_eof (void);
static int gcov_is_error (void);
#if IN_GCOV > 0
static time_t gcov_time (void);
#endif

/* Open a gcov file. NAME is the name of the file to open and MODE
   indicates whether a new file should be created, or an existing file
   opened for modification. If MODE is >= 0 an existing file will be
   opened, if possible, and if MODE is <= 0, a new file will be
   created. Use MODE=0 to attempt to reopen an existing file and then
   fall back on creating a new one.  Return zero on failure, >0 on
   opening an existing file and <0 on creating a new one.  */

static int
gcov_open (const char *name, int mode)
{
  int result = 1;
  size_t alloc = 1024;
#if defined (TARGET_HAS_F_SETLKW) && IN_LIBGCOV
  struct flock s_flock;

  s_flock.l_type = F_WRLCK;
  s_flock.l_whence = SEEK_SET;
  s_flock.l_start = 0;
  s_flock.l_len = 0; /* Until EOF.  */
  s_flock.l_pid = getpid ();
#endif
  
  if (gcov_var.file)
    abort ();
  gcov_var.position = gcov_var.length = 0;
  gcov_var.error = gcov_var.modified = 0;
  if (mode >= 0)
    gcov_var.file = fopen (name, "r+b");
  if (!gcov_var.file && mode <= 0)
    {
      result = -1;
      gcov_var.file = fopen (name, "w+b");
    }
  if (!gcov_var.file)
    return 0;

#if defined (TARGET_HAS_F_SETLKW) && IN_LIBGCOV
  while (fcntl (fileno (gcov_var.file), F_SETLKW, &s_flock)
         && errno == EINTR)
    continue;
#endif

  if (result >= 0)
    {
      if (fseek (gcov_var.file, 0, SEEK_END))
        {
          fclose (gcov_var.file);
          gcov_var.file = 0;
          return 0;
        }
      gcov_var.length = ftell (gcov_var.file);
      fseek (gcov_var.file, 0, SEEK_SET);
      alloc += gcov_var.length;
    }
  if (alloc > gcov_var.alloc)
    {
      if (gcov_var.buffer)
        free (gcov_var.buffer);
      gcov_var.alloc = alloc;
#if IN_LIBGCOV
      gcov_var.buffer = malloc (gcov_var.alloc);
      if (!gcov_var.buffer)
        {
          fclose (gcov_var.file);
          gcov_var.file = 0;
          gcov_var.length = 0;
          gcov_var.alloc = 0;
          return 0;
        }
#else
      gcov_var.buffer = xmalloc (gcov_var.alloc);
#endif
    }
  if (result >= 0
      && fread (gcov_var.buffer, gcov_var.length, 1, gcov_var.file) != 1)
    {
      fclose (gcov_var.file);
      gcov_var.file = 0;
      gcov_var.length = 0;
      return 0;
    }
  return result;
}

/* Close the current gcov file. Flushes data to disk. Returns nonzero
   on failure or error flag set.  */

static int
gcov_close ()
{
  int result = 0;
  
  if (gcov_var.file)
    {
      if (gcov_var.modified
          && (fseek (gcov_var.file, 0, SEEK_SET)
              || fwrite (gcov_var.buffer, gcov_var.length,
                         1, gcov_var.file) != 1))
        result = 1;
      fclose (gcov_var.file);
      gcov_var.file = 0;
      gcov_var.length = 0;
    }
#if !IN_LIBGCOV
  free (gcov_var.buffer);
  gcov_var.alloc = 0;
  gcov_var.buffer = 0;
#endif
  return result ? 1 : gcov_var.error;
}

#if !IN_GCOV
/* Allocate space to write BYTES bytes to the gcov file. Return a
   pointer to those bytes, or NULL on failure.  */

static unsigned char *
gcov_write_bytes (unsigned bytes)
{
  char unsigned *result;

  if (gcov_var.position + bytes > gcov_var.alloc)
    {
      size_t new_size = (gcov_var.alloc + bytes) * 3 / 2;

      if (!gcov_var.buffer)
        return 0;
#if IN_LIBGCOV
      result = realloc (gcov_var.buffer, new_size);
      if (!result)
        {
          free (gcov_var.buffer);
          gcov_var.buffer = 0;
          gcov_var.alloc = 0;
          gcov_var.position = gcov_var.length = 0;
          gcov_var.error = 1;
          return 0;
        }
#else
      result = xrealloc (gcov_var.buffer, new_size);
#endif
      gcov_var.alloc = new_size;
      gcov_var.buffer = result;
    }
  
  result = &gcov_var.buffer[gcov_var.position];
  gcov_var.position += bytes;
  gcov_var.modified = 1;
  if (gcov_var.position > gcov_var.length)
    gcov_var.length = gcov_var.position;
  return result;
}

/* Write unsigned VALUE to coverage file.  Sets error flag
   appropriately.  */

static void
gcov_write_unsigned (unsigned value)
{
  unsigned char *buffer = gcov_write_bytes (4);
  unsigned ix;

  if (!buffer)
    return;
  for (ix = 4; ix--; )
    {
      buffer[ix] = value;
      value >>= 8;
    }
  if (sizeof (value) > 4 && value)
    gcov_var.error = -1;

  return;
}

/* Write counter VALUE to coverage file.  Sets error flag
   appropriately.  */

#if IN_LIBGCOV
static void
gcov_write_counter (gcov_type value)
{
  unsigned char *buffer = gcov_write_bytes (8);
  unsigned ix;

  if (!buffer)
    return;
  for (ix = 8; ix--; )
    {
      buffer[ix] = value;
      value >>= 8;
    }
  if ((sizeof (value) > 8 && value) || value < 0)
    gcov_var.error = -1;
  return;
}
#endif /* IN_LIBGCOV */

/* Write STRING to coverage file.  Sets error flag on file
   error, overflow flag on overflow */

static void
gcov_write_string (const char *string)
{
  unsigned length = 0;
  unsigned pad = 0;
  unsigned rem = 0;
  unsigned char *buffer;

  if (string)
    {
      length = strlen (string);
      rem = 4 - (length & 3);
    }
  
  buffer = gcov_write_bytes (4 + length + rem);
  if (buffer)
    {
      unsigned ix;
      unsigned value = length;
      
      for (ix = 4; ix--; )
        {
          buffer[ix] = value;
          value >>= 8;
        }
      memcpy (buffer + 4, string, length);
      memcpy (buffer + 4 + length, &pad, rem);
    }
}

/* Write a tag TAG and reserve space for the record length. Return a
   value to be used for gcov_write_length.  */

static unsigned long
gcov_write_tag (unsigned tag)
{
  unsigned long result = gcov_var.position;
  unsigned char *buffer = gcov_write_bytes (8);
  unsigned ix;

  if (!buffer)
    return 0;
  for (ix = 4; ix--; )
    {
      buffer[ix] = tag;
      tag >>= 8;
    }
  memset (buffer + 4, 0, 4);
  return result;
}

/* Write a record length using POSITION, which was returned by
   gcov_write_tag.  The current file position is the end of the
   record, and is restored before returning.  Returns nonzero on
   overflow.  */

static void
gcov_write_length (unsigned long position)
{
  if (position)
    {
      unsigned length = gcov_var.position - position - 8;
      unsigned char *buffer = &gcov_var.buffer[position + 4];
      unsigned ix;
      
      for (ix = 4; ix--; )
        {
          buffer[ix] = length;
          length >>= 8;
        }
    }
}

#if IN_LIBGCOV
/* Write a summary structure to the gcov file.  Return non-zero on
   overflow.  */

static void
gcov_write_summary (unsigned tag, const struct gcov_summary *summary)
{
  unsigned long base;

  base = gcov_write_tag (tag);
  gcov_write_unsigned (summary->checksum);
  gcov_write_unsigned (summary->runs);
  gcov_write_unsigned (summary->arcs);
  gcov_write_counter (summary->arc_sum);
  gcov_write_counter (summary->arc_max_one);
  gcov_write_counter (summary->arc_max_sum);
  gcov_write_counter (summary->arc_sum_max);
  gcov_write_length (base);
}
#endif /* IN_LIBGCOV */

#endif /*!IN_GCOV */

/* Return a pointer to read BYTES bytes from the gcov file. Returns
   NULL on failure (read past EOF). */

static const unsigned char *
gcov_read_bytes (unsigned bytes)
{
  const unsigned char *result;
  
  if (gcov_var.position + bytes > gcov_var.length)
    {
      gcov_var.error = 1;
      return 0;
    }
  
  result = &gcov_var.buffer[gcov_var.position];
  gcov_var.position += bytes;
  return result;
}

/* Read unsigned value from a coverage file. Sets error flag on file
   error, overflow flag on overflow */

static unsigned
gcov_read_unsigned ()
{
  unsigned value = 0;
  unsigned ix;
  const unsigned char *buffer = gcov_read_bytes (4);

  if (!buffer)
    return 0;
  for (ix = sizeof (value); ix < 4; ix++)
    if (buffer[ix])
      gcov_var.error = -1;
  for (ix = 0; ix != 4; ix++)
    {
      value <<= 8;
      value |= buffer[ix];
    }
  return value;
}

/* Read counter value from a coverage file. Sets error flag on file
   error, overflow flag on overflow */

static gcov_type
gcov_read_counter ()
{
  gcov_type value = 0;
  unsigned ix;
  const unsigned char *buffer = gcov_read_bytes (8);

  if (!buffer)
    return 0;
  for (ix = sizeof (value); ix < 8; ix++)
    if (buffer[ix])
      gcov_var.error = -1;
  for (ix = 0; ix != 8; ix++)
    {
      value <<= 8;
      value |= buffer[ix];
    }
  if (value < 0)
    gcov_var.error = -1;
  return value;
}

/* Read string from coverage file. Returns a pointer to a static
   buffer, or NULL on empty string. You must copy the string before
   calling another gcov function.  */

static const char *
gcov_read_string ()
{
  unsigned length = gcov_read_unsigned ();
  
  if (!length)
    return 0;

  length += 4 - (length & 3);
  return (const char *) gcov_read_bytes (length);
}

#define GCOV_SUMMARY_LENGTH 44
static void
gcov_read_summary (struct gcov_summary *summary)
{
  summary->checksum = gcov_read_unsigned ();
  summary->runs = gcov_read_unsigned ();
  summary->arcs = gcov_read_unsigned ();
  summary->arc_sum = gcov_read_counter ();
  summary->arc_max_one = gcov_read_counter ();
  summary->arc_max_sum =  gcov_read_counter ();
  summary->arc_sum_max = gcov_read_counter ();
}

/* Save the current position in the gcov file.  */

static inline unsigned long
gcov_position (void)
{
  return gcov_var.position;
}

/* Reset to a known position.  BASE should have been obtained from
   gcov_save_position, LENGTH should be a record length, or zero.  */

static inline void
gcov_seek (unsigned long base, unsigned length)
{
  if (gcov_var.buffer)
    {
      base += length;
      if (gcov_var.length < base)
        {
          gcov_var.error = 1;
          base = gcov_var.length;
        }
      gcov_var.position = base;
    }
}

/* Move to the end of the gcov file.  */

static inline unsigned long
gcov_seek_end ()
{
  gcov_var.position = gcov_var.length;
  return gcov_var.position;
}

/* Tests whether we have reached end of .da file.  */

static inline int
gcov_is_eof ()
{
  return gcov_var.position == gcov_var.length;
}

/* Return non-zero if the error flag is set.  */

static inline int
gcov_is_error ()
{
  return gcov_var.file ? gcov_var.error : 1;
}

#if IN_GCOV > 0
/* Return the modification time of the current gcov file.  */

static time_t
gcov_time ()
{
  struct stat status;
  
  if (fstat (fileno (gcov_var.file), &status))
    return 0;
  else
    return status.st_mtime;
}
#endif /* IN_GCOV */
#endif /* GCC_GCOV_IO_H */