gcc/vec.c

/* Vector API for GNU compiler.
   Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   Contributed 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 3, 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 COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

/* This file is compiled twice: once for the generator programs
   once for the compiler.  */
#ifdef GENERATOR_FILE
#include "bconfig.h"
#else
#include "config.h"
#endif

#include "system.h"
#include "ggc.h"
#include "vec.h"
#include "coretypes.h"
#include "toplev.h"
#include "hashtab.h"

struct vec_prefix 
{
  unsigned num;
  unsigned alloc;
  void *vec[1];
};


#ifdef GATHER_STATISTICS

/* Store information about each particular vector.  */
struct vec_descriptor
{
  const char *function;
  const char *file;
  int line;
  size_t allocated;
  size_t times;
  size_t peak;
};


/* Hashtable mapping vec addresses to descriptors.  */
static htab_t vec_desc_hash;

/* Hashtable helpers.  */
static hashval_t
hash_descriptor (const void *p)
{
  const struct vec_descriptor *const d =
    (const struct vec_descriptor *) p;
  return htab_hash_pointer (d->file) + d->line;
}
static int
eq_descriptor (const void *p1, const void *p2)
{
  const struct vec_descriptor *const d = (const struct vec_descriptor *) p1;
  const struct vec_descriptor *const l = (const struct vec_descriptor *) p2;
  return d->file == l->file && d->function == l->function && d->line == l->line;
}

/* Hashtable converting address of allocated field to loc descriptor.  */
static htab_t ptr_hash;
struct ptr_hash_entry
{
  void *ptr;
  struct vec_descriptor *loc;
  size_t allocated;
};

/* Hash table helpers functions.  */
static hashval_t
hash_ptr (const void *p)
{
  const struct ptr_hash_entry *const d = (const struct ptr_hash_entry *) p;

  return htab_hash_pointer (d->ptr);
}

static int
eq_ptr (const void *p1, const void *p2)
{
  const struct ptr_hash_entry *const p = (const struct ptr_hash_entry *) p1;

  return (p->ptr == p2);
}

/* Return descriptor for given call site, create new one if needed.  */
static struct vec_descriptor *
vec_descriptor (const char *name, int line, const char *function)
{
  struct vec_descriptor loc;
  struct vec_descriptor **slot;

  loc.file = name;
  loc.line = line;
  loc.function = function;
  if (!vec_desc_hash)
    vec_desc_hash = htab_create (10, hash_descriptor, eq_descriptor, NULL);

  slot = (struct vec_descriptor **) htab_find_slot (vec_desc_hash, &loc, 1);
  if (*slot)
    return *slot;
  *slot = XCNEW (struct vec_descriptor);
  (*slot)->file = name;
  (*slot)->line = line;
  (*slot)->function = function;
  (*slot)->allocated = 0;
  (*slot)->peak = 0;
  return *slot;
}

/* Account the overhead.  */
static void
register_overhead (struct vec_prefix *ptr, size_t size,
		   const char *name, int line, const char *function)
{
  struct vec_descriptor *loc = vec_descriptor (name, line, function);
  struct ptr_hash_entry *p = XNEW (struct ptr_hash_entry);
  PTR *slot;

  p->ptr = ptr;
  p->loc = loc;
  p->allocated = size;
  if (!ptr_hash)
    ptr_hash = htab_create (10, hash_ptr, eq_ptr, NULL);
  slot = htab_find_slot_with_hash (ptr_hash, ptr, htab_hash_pointer (ptr), INSERT);
  gcc_assert (!*slot);
  *slot = p;

  loc->allocated += size;
  if (loc->peak < loc->allocated)
    loc->peak += loc->allocated;
  loc->times++;
}

/* Notice that the pointer has been freed.  */
static void
free_overhead (struct vec_prefix *ptr)
{
  PTR *slot = htab_find_slot_with_hash (ptr_hash, ptr, htab_hash_pointer (ptr),
					NO_INSERT);
  struct ptr_hash_entry *p = (struct ptr_hash_entry *) *slot;
  p->loc->allocated -= p->allocated;
  htab_clear_slot (ptr_hash, slot);
  free (p);
}

void
vec_heap_free (void *ptr)
{
  free_overhead ((struct vec_prefix *)ptr);
  free (ptr);
}
#endif

/* Calculate the new ALLOC value, making sure that RESERVE slots are
   free.  If EXACT grow exactly, otherwise grow exponentially.  */

static inline unsigned
calculate_allocation (const struct vec_prefix *pfx, int reserve, bool exact)
{
  unsigned alloc = 0;
  unsigned num = 0;

  gcc_assert (reserve >= 0);

  if (pfx)
    {
      alloc = pfx->alloc;
      num = pfx->num;
    }
  else if (!reserve)
    /* If there's no prefix, and we've not requested anything, then we
       will create a NULL vector.  */
    return 0;
  
  /* We must have run out of room.  */
  gcc_assert (alloc - num < (unsigned) reserve);
  
  if (exact)
    /* Exact size.  */
    alloc = num + reserve;
  else
    {
      /* Exponential growth. */
      if (!alloc)
	alloc = 4;
      else if (alloc < 16)
	/* Double when small.  */
	alloc = alloc * 2;
      else
	/* Grow slower when large.  */
	alloc = (alloc * 3 / 2);
      
      /* If this is still too small, set it to the right size. */
      if (alloc < num + reserve)
	alloc = num + reserve;
    }
  return alloc;
}

/* Ensure there are at least RESERVE free slots in VEC.  If EXACT grow
   exactly, else grow exponentially.  As a special case, if VEC is
   NULL and RESERVE is 0, no vector will be created.  The vector's
   trailing array is at VEC_OFFSET offset and consists of ELT_SIZE
   sized elements.  */

static void *
vec_gc_o_reserve_1 (void *vec, int reserve, size_t vec_offset, size_t elt_size,
		    bool exact MEM_STAT_DECL)
{
  struct vec_prefix *pfx = (struct vec_prefix *) vec;
  unsigned alloc = alloc = calculate_allocation (pfx, reserve, exact);
  
  if (!alloc)
    {
      if (pfx)
        ggc_free (pfx);
      return NULL;
    }
  
  vec = ggc_realloc_stat (vec, vec_offset + alloc * elt_size PASS_MEM_STAT);
  ((struct vec_prefix *)vec)->alloc = alloc;
  if (!pfx)
    ((struct vec_prefix *)vec)->num = 0;
  
  return vec;
}

/* Ensure there are at least RESERVE free slots in VEC, growing
   exponentially.  If RESERVE < 0 grow exactly, else grow
   exponentially.  As a special case, if VEC is NULL, and RESERVE is
   0, no vector will be created. */

void *
vec_gc_p_reserve (void *vec, int reserve MEM_STAT_DECL)
{
  return vec_gc_o_reserve_1 (vec, reserve,
			     offsetof (struct vec_prefix, vec),
			     sizeof (void *), false
			     PASS_MEM_STAT);
}

/* Ensure there are at least RESERVE free slots in VEC, growing
   exactly.  If RESERVE < 0 grow exactly, else grow exponentially.  As
   a special case, if VEC is NULL, and RESERVE is 0, no vector will be
   created. */

void *
vec_gc_p_reserve_exact (void *vec, int reserve MEM_STAT_DECL)
{
  return vec_gc_o_reserve_1 (vec, reserve,
			     offsetof (struct vec_prefix, vec),
			     sizeof (void *), true
			     PASS_MEM_STAT);
}

/* As for vec_gc_p_reserve, but for object vectors.  The vector's
   trailing array is at VEC_OFFSET offset and consists of ELT_SIZE
   sized elements.  */

void *
vec_gc_o_reserve (void *vec, int reserve, size_t vec_offset, size_t elt_size
		  MEM_STAT_DECL)
{
  return vec_gc_o_reserve_1 (vec, reserve, vec_offset, elt_size, false
			     PASS_MEM_STAT);
}

/* As for vec_gc_p_reserve_exact, but for object vectors.  The
   vector's trailing array is at VEC_OFFSET offset and consists of
   ELT_SIZE sized elements.  */

void *
vec_gc_o_reserve_exact (void *vec, int reserve, size_t vec_offset,
			size_t elt_size MEM_STAT_DECL)
{
  return vec_gc_o_reserve_1 (vec, reserve, vec_offset, elt_size, true
			     PASS_MEM_STAT);
}

/* As for vec_gc_o_reserve_1, but for heap allocated vectors.  */

static void *
vec_heap_o_reserve_1 (void *vec, int reserve, size_t vec_offset,
		      size_t elt_size, bool exact MEM_STAT_DECL)
{
  struct vec_prefix *pfx = (struct vec_prefix *) vec;
  unsigned alloc = calculate_allocation (pfx, reserve, exact);

  if (!alloc)
    {
      if (pfx)
        vec_heap_free (pfx);
      return NULL;
    }

#ifdef GATHER_STATISTICS
  if (vec)
    free_overhead (pfx);
#endif
  
  vec = xrealloc (vec, vec_offset + alloc * elt_size);
  ((struct vec_prefix *)vec)->alloc = alloc;
  if (!pfx)
    ((struct vec_prefix *)vec)->num = 0;
#ifdef GATHER_STATISTICS
  if (vec)
    register_overhead ((struct vec_prefix *)vec,
    		       vec_offset + alloc * elt_size PASS_MEM_STAT);
#endif
  
  return vec;
}

/* As for vec_gc_p_reserve, but for heap allocated vectors.  */

void *
vec_heap_p_reserve (void *vec, int reserve MEM_STAT_DECL)
{
  return vec_heap_o_reserve_1 (vec, reserve,
			       offsetof (struct vec_prefix, vec),
			       sizeof (void *), false
			       PASS_MEM_STAT);
}

/* As for vec_gc_p_reserve_exact, but for heap allocated vectors.  */

void *
vec_heap_p_reserve_exact (void *vec, int reserve MEM_STAT_DECL)
{
  return vec_heap_o_reserve_1 (vec, reserve,
			       offsetof (struct vec_prefix, vec),
			       sizeof (void *), true
			       PASS_MEM_STAT);
}

/* As for vec_gc_o_reserve, but for heap allocated vectors.  */

void *
vec_heap_o_reserve (void *vec, int reserve, size_t vec_offset, size_t elt_size
		    MEM_STAT_DECL)
{
  return vec_heap_o_reserve_1 (vec, reserve, vec_offset, elt_size, false
			       PASS_MEM_STAT);
}

/* As for vec_gc_o_reserve_exact, but for heap allocated vectors.  */

void *
vec_heap_o_reserve_exact (void *vec, int reserve, size_t vec_offset,
			  size_t elt_size MEM_STAT_DECL)
{
  return vec_heap_o_reserve_1 (vec, reserve, vec_offset, elt_size, true
			       PASS_MEM_STAT);
}

#if ENABLE_CHECKING
/* Issue a vector domain error, and then fall over.  */

void
vec_assert_fail (const char *op, const char *struct_name,
		 const char *file, unsigned int line, const char *function)
{
  internal_error ("vector %s %s domain error, in %s at %s:%u",
		  struct_name, op, function, trim_filename (file), line);
}
#endif

#ifdef GATHER_STATISTICS
/* Helper for qsort; sort descriptors by amount of memory consumed.  */
static int
cmp_statistic (const void *loc1, const void *loc2)
{
  const struct vec_descriptor *const l1 =
    *(const struct vec_descriptor *const *) loc1;
  const struct vec_descriptor *const l2 =
    *(const struct vec_descriptor *const *) loc2;
  long diff;
  diff = l1->allocated - l2->allocated;
  if (!diff)
    diff = l1->peak - l2->peak;
  if (!diff)
    diff = l1->times - l2->times;
  return diff > 0 ? 1 : diff < 0 ? -1 : 0;
}
/* Collect array of the descriptors from hashtable.  */
static struct vec_descriptor **loc_array;
static int
add_statistics (void **slot, void *b)
{
  int *n = (int *)b;
  loc_array[*n] = (struct vec_descriptor *) *slot;
  (*n)++;
  return 1;
}

/* Dump per-site memory statistics.  */
#endif
void
dump_vec_loc_statistics (void)
{
#ifdef GATHER_STATISTICS
  int nentries = 0;
  char s[4096];
  size_t allocated = 0;
  size_t times = 0;
  int i;

  loc_array = XCNEWVEC (struct vec_descriptor *, vec_desc_hash->n_elements);
  fprintf (stderr, "Heap vectors:\n");
  fprintf (stderr, "\n%-48s %10s       %10s       %10s\n",
	   "source location", "Leak", "Peak", "Times");
  fprintf (stderr, "-------------------------------------------------------\n");
  htab_traverse (vec_desc_hash, add_statistics, &nentries);
  qsort (loc_array, nentries, sizeof (*loc_array), cmp_statistic);
  for (i = 0; i < nentries; i++)
    {
      struct vec_descriptor *d = loc_array[i];
      allocated += d->allocated;
      times += d->times;
    }
  for (i = 0; i < nentries; i++)
    {
      struct vec_descriptor *d = loc_array[i];
      const char *s1 = d->file;
      const char *s2;
      while ((s2 = strstr (s1, "gcc/")))
	s1 = s2 + 4;
      sprintf (s, "%s:%i (%s)", s1, d->line, d->function);
      s[48] = 0;
      fprintf (stderr, "%-48s %10li:%4.1f%% %10li      %10li:%4.1f%% \n", s,
	       (long)d->allocated,
	       (d->allocated) * 100.0 / allocated,
	       (long)d->peak,
	       (long)d->times,
	       (d->times) * 100.0 / times);
    }
  fprintf (stderr, "%-48s %10ld                        %10ld\n",
	   "Total", (long)allocated, (long)times);
  fprintf (stderr, "\n%-48s %10s       %10s       %10s\n",
	   "source location", "Leak", "Peak", "Times");
  fprintf (stderr, "-------------------------------------------------------\n");
#endif
}