gcc/gcc/gcov-io.h

/* File format for coverage information
   Copyright (C) 1996, 1997, 1998, 2000, 2002,
   2003 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.  */

/* As a special exception, if you link this library with other files,
   some of which are compiled with GCC, to produce an executable,
   this library does not by itself cause the resulting executable
   to be covered by the GNU General Public License.
   This exception does not however invalidate any other reasons why
   the executable file might be covered by the GNU General Public License.  */

/* 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: int32:checksum {count-summary}GCOV_COUNTERS
	count-summary:	int32:num int32:runs int64:sum
			int64:max 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
#if defined (TARGET_HAS_F_SETLKW)
#define GCOV_LOCKED 1
#else
#define GCOV_LOCKED 0
#endif
#endif /* IN_LIBGCOV */
#if IN_GCOV
typedef HOST_WIDEST_INT gcov_type;
#if IN_GCOV > 0
#include <sys/types.h>
#endif
#endif

/* In lib gcov we want function linkage to be static, so we do not
   polute the global namespace. In the compiler we want it extern, so
   that they can be accessed from elsewhere.  */
#if IN_LIBGCOV || IN_GCOV
#define GCOV_LINKAGE static
#else
#ifndef GCOV_LINKAGE
#define GCOV_LINKAGE extern
#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_COUNTER_BASE 	 ((unsigned)0x01a10000) /* First counter */
#define GCOV_TAG_OBJECT_SUMMARY  ((unsigned)0xa1000000)
#define GCOV_TAG_PROGRAM_SUMMARY ((unsigned)0xa3000000)

/* Counters that are collected.  */
#define GCOV_COUNTER_ARCS 	0  /* Arc transitions.  */
#define GCOV_COUNTERS		1

/* A list of human readable names of the counters */
#define GCOV_COUNTER_NAMES	{"arcs"}

/* Convert a counter index to a tag. */
#define GCOV_TAG_FOR_COUNTER(COUNT)				\
	(GCOV_TAG_COUNTER_BASE + ((COUNT) << 17))
/* Convert a tag to a counter.  */
#define GCOV_COUNTER_FOR_TAG(TAG)					\
	(((TAG) - GCOV_TAG_COUNTER_BASE) >> 17)
/* Check whether a tag is a counter tag.  */
#define GCOV_TAG_IS_COUNTER(TAG)				\
	(!((TAG) & 0xFFFF) && GCOV_COUNTER_FOR_TAG (TAG) < GCOV_COUNTERS)

/* 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.  */

/* Cumulative counter data.   */
struct gcov_ctr_summary
{
  unsigned num;		/* number of counters.  */
  unsigned runs;	/* number of program runs */
  gcov_type sum_all;	/* sum of all counters accumulated. */
  gcov_type run_max;	/* maximum value on a single run.  */
  gcov_type sum_max;    /* sum of individual run max values. */
};

/* Object & program summary record.  */
struct gcov_summary
{
  unsigned checksum;	  /* checksum of program */
  struct gcov_ctr_summary ctrs[GCOV_COUNTERS];
};

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

#if IN_LIBGCOV
/* Information about a single function.  This uses the trailing array
   idiom. The number of counters is determined from the counter_mask
   in gcov_info.  We hold an array of function info, so have to
   explicitly calculate the correct array stride.  */
struct gcov_fn_info
{
  const char *name;	        /* (mangled) name of function */
  unsigned checksum;		/* function checksum */
  unsigned n_ctrs[0];		/* instrumented counters */
};

/* Information about counters.  */
struct gcov_ctr_info
{
  unsigned num;		/* number of counters.  */
  gcov_type *values;	/* their values.  */
};

/* 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 */

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

  unsigned ctr_mask;              /* mask of counters instrumented.  */
  struct gcov_ctr_info counts[0]; /* count data. The number of bits
				     set in the ctr_mask field
				     determines how big this array
				     is.  */
};

/* 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);

#endif /* IN_LIBGCOV */

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

GCOV_LINKAGE 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.  */
GCOV_LINKAGE int gcov_open (const char */*name*/, int /*truncate*/);
GCOV_LINKAGE int gcov_close (void);
#if !IN_GCOV
GCOV_LINKAGE unsigned char *gcov_write_bytes (unsigned);
GCOV_LINKAGE void gcov_write_unsigned (unsigned);
#if IN_LIBGCOV
GCOV_LINKAGE void gcov_write_counter (gcov_type);
#endif
GCOV_LINKAGE void gcov_write_string (const char *);
GCOV_LINKAGE unsigned long gcov_write_tag (unsigned);
GCOV_LINKAGE void gcov_write_length (unsigned long /*position*/);
#if IN_LIBGCOV
GCOV_LINKAGE void gcov_write_summary (unsigned, const struct gcov_summary *);
#endif
#endif /* !IN_GCOV */
GCOV_LINKAGE const unsigned char *gcov_read_bytes (unsigned);
GCOV_LINKAGE unsigned gcov_read_unsigned (void);
GCOV_LINKAGE gcov_type gcov_read_counter (void);
GCOV_LINKAGE const char *gcov_read_string (void);
GCOV_LINKAGE 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
GCOV_LINKAGE time_t gcov_time (void);
#endif

/* 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;
}

#endif /* GCC_GCOV_IO_H */