gcc/ggc.h

/* Garbage collection for the GNU compiler.

   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007,
   2008, 2009, 2010 Free Software Foundation, Inc.

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/>.  */

#ifndef GCC_GGC_H
#define GCC_GGC_H
#include "statistics.h"

/* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
   an external gc library that might be linked in.  */

/* Constants for general use.  */
extern const char empty_string[];	/* empty string */

/* Internal functions and data structures used by the GTY
   machinery, including the generated gt*.[hc] files.  */

/* The first parameter is a pointer to a pointer, the second a cookie.  */
typedef void (*gt_pointer_operator) (void *, void *);

#include "gtype-desc.h"

/* One of these applies its third parameter (with cookie in the fourth
   parameter) to each pointer in the object pointed to by the first
   parameter, using the second parameter.  */
typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
				  void *);

/* One of these is called before objects are re-ordered in memory.
   The first parameter is the original object, the second is the
   subobject that has had its pointers reordered, the third parameter
   can compute the new values of a pointer when given the cookie in
   the fourth parameter.  */
typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
				   void *);

/* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
extern int gt_pch_note_object (void *, void *, gt_note_pointers,
			       enum gt_types_enum);

/* Used by the gt_pch_n_* routines.  Register that an object has a reorder
   function.  */
extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);

/* Mark the object in the first parameter and anything it points to.  */
typedef void (*gt_pointer_walker) (void *);

/* Structures for the easy way to mark roots.
   In an array, terminated by having base == NULL.  */
struct ggc_root_tab {
  void *base;
  size_t nelt;
  size_t stride;
  gt_pointer_walker cb;
  gt_pointer_walker pchw;
};
#define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
/* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
extern const struct ggc_root_tab * const gt_ggc_rtab[];
extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
extern const struct ggc_root_tab * const gt_pch_cache_rtab[];
extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];

/* Structure for hash table cache marking.  */
struct htab;
struct ggc_cache_tab {
  struct htab * *base;
  size_t nelt;
  size_t stride;
  gt_pointer_walker cb;
  gt_pointer_walker pchw;
  int (*marked_p) (const void *);
};
#define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
/* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];

/* If EXPR is not NULL and previously unmarked, mark it and evaluate
   to true.  Otherwise evaluate to false.  */
#define ggc_test_and_set_mark(EXPR) \
  ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))

#define ggc_mark(EXPR)				\
  do {						\
    const void *const a__ = (EXPR);		\
    if (a__ != NULL && a__ != (void *) 1)	\
      ggc_set_mark (a__);			\
  } while (0)

/* Actually set the mark on a particular region of memory, but don't
   follow pointers.  This function is called by ggc_mark_*.  It
   returns zero if the object was not previously marked; nonzero if
   the object was already marked, or if, for any other reason,
   pointers in this data structure should not be traversed.  */
extern int ggc_set_mark	(const void *);

/* Return 1 if P has been marked, zero otherwise.
   P must have been allocated by the GC allocator; it mustn't point to
   static objects, stack variables, or memory allocated with malloc.  */
extern int ggc_marked_p	(const void *);

/* PCH and GGC handling for strings, mostly trivial.  */
extern void gt_pch_n_S (const void *);
extern void gt_ggc_m_S (const void *);

/* End of GTY machinery API.  */

struct alloc_zone;

/* Initialize the string pool.  */
extern void init_stringpool (void);

/* Initialize the garbage collector.  */
extern void init_ggc (void);

/* When true, identifier nodes are considered as GC roots.  When
   false, identifier nodes are treated like any other GC-allocated
   object, and the identifier hash table is treated as a weak
   hash.  */
extern bool ggc_protect_identifiers;

/* Write out all GCed objects to F.  */
extern void gt_pch_save (FILE *f);


/* Allocation.  */

/* The internal primitive.  */
extern void *ggc_internal_alloc_stat (size_t MEM_STAT_DECL);

#define ggc_internal_alloc(s) ggc_internal_alloc_stat (s MEM_STAT_INFO)

/* Allocate an object of the specified type and size.  */
extern void *ggc_alloc_typed_stat (enum gt_types_enum, size_t MEM_STAT_DECL);

#define ggc_alloc_typed(s, z) ggc_alloc_typed_stat (s, z MEM_STAT_INFO)

/* Allocates cleared memory.  */
extern void *ggc_internal_cleared_alloc_stat (size_t MEM_STAT_DECL);

/* Resize a block.  */
extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);

/* Free a block.  To be used when known for certain it's not reachable.  */
extern void ggc_free (void *);

extern void ggc_record_overhead (size_t, size_t, void * MEM_STAT_DECL);
extern void ggc_free_overhead (void *);
extern void ggc_prune_overhead_list (void);

extern void dump_ggc_loc_statistics (bool);

/* Reallocators.  */
#define GGC_RESIZEVEC(T, P, N) \
    ((T *) ggc_realloc_stat ((P), (N) * sizeof (T) MEM_STAT_INFO))

#define GGC_RESIZEVAR(T, P, N)                          \
    ((T *) ggc_realloc_stat ((P), (N) MEM_STAT_INFO))

static inline void *
ggc_internal_vec_alloc_stat (size_t s, size_t c MEM_STAT_DECL)
{
    return ggc_internal_alloc_stat (c * s PASS_MEM_STAT);
}

static inline void *
ggc_internal_cleared_vec_alloc_stat (size_t s, size_t c MEM_STAT_DECL)
{
    return ggc_internal_cleared_alloc_stat (c * s PASS_MEM_STAT);
}

#define ggc_internal_cleared_vec_alloc(s, c) \
    (ggc_internal_cleared_vec_alloc_stat ((s), (c) MEM_STAT_INFO))

static inline void *
ggc_alloc_atomic_stat (size_t s MEM_STAT_DECL)
{
    return ggc_internal_alloc_stat (s PASS_MEM_STAT);
}

#define ggc_alloc_atomic(S)  (ggc_alloc_atomic_stat ((S) MEM_STAT_INFO))

#define ggc_alloc_cleared_atomic(S)             \
    (ggc_internal_cleared_alloc_stat ((S) MEM_STAT_INFO))

extern void * ggc_cleared_alloc_htab_ignore_args (size_t, size_t);

extern void * ggc_cleared_alloc_ptr_array_two_args (size_t, size_t);

#define htab_create_ggc(SIZE, HASH, EQ, DEL) \
  htab_create_typed_alloc (SIZE, HASH, EQ, DEL,	\
			   ggc_cleared_alloc_htab_ignore_args,		\
			   ggc_cleared_alloc_ptr_array_two_args,	\
			   ggc_free)

#define splay_tree_new_ggc(COMPARE, ALLOC_TREE, ALLOC_NODE)		     \
  splay_tree_new_typed_alloc (COMPARE, NULL, NULL, &ALLOC_TREE, &ALLOC_NODE, \
			      &ggc_splay_dont_free, NULL)

extern void *ggc_splay_alloc (enum gt_types_enum, int, void *);

extern void ggc_splay_dont_free (void *, void *);

/* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
   If LENGTH is -1, then CONTENTS is assumed to be a
   null-terminated string and the memory sized accordingly.  */
extern const char *ggc_alloc_string_stat (const char *contents, int length
                                          MEM_STAT_DECL);

#define ggc_alloc_string(c, l) ggc_alloc_string_stat (c, l MEM_STAT_INFO)

/* Make a copy of S, in GC-able memory.  */
#define ggc_strdup(S) ggc_alloc_string_stat ((S), -1 MEM_STAT_INFO)

/* Invoke the collector.  Garbage collection occurs only when this
   function is called, not during allocations.  */
extern void ggc_collect	(void);

/* Register an additional root table.  This can be useful for some
   plugins.  Does nothing if the passed pointer is NULL. */
extern void ggc_register_root_tab (const struct ggc_root_tab *);

/* Register an additional cache table.  This can be useful for some
   plugins.  Does nothing if the passed pointer is NULL. */
extern void ggc_register_cache_tab (const struct ggc_cache_tab *);

/* Read objects previously saved with gt_pch_save from F.  */
extern void gt_pch_restore (FILE *f);

/* Statistics.  */

/* Print allocation statistics.  */
extern void ggc_print_statistics (void);

extern void stringpool_statistics (void);

/* Heuristics.  */
extern void init_ggc_heuristics (void);

/* Zone collection.  */

/* For regular rtl allocations.  */
extern struct alloc_zone rtl_zone;

/* For regular tree allocations.  */
extern struct alloc_zone tree_zone;

/* For IDENTIFIER_NODE allocations.  */
extern struct alloc_zone tree_id_zone;

#define ggc_alloc_rtvec_sized(NELT)                                     \
    (ggc_alloc_zone_vec_rtvec_def (sizeof (rtx),                        \
                                   sizeof (struct rtvec_def) + ((NELT) - 1), \
                                   &rtl_zone))

#if defined (GGC_ZONE) && !defined (GENERATOR_FILE)

/* Allocate an object into the specified allocation zone.  */
extern void *ggc_internal_alloc_zone_stat (size_t,
					  struct alloc_zone * MEM_STAT_DECL);

extern void *ggc_internal_cleared_alloc_zone_stat (size_t,
					  struct alloc_zone * MEM_STAT_DECL);

static inline void *
ggc_internal_zone_alloc_stat (struct alloc_zone * z, size_t s MEM_STAT_DECL)
{
    return ggc_internal_alloc_zone_stat (s, z PASS_MEM_STAT);
}

static inline void *
ggc_internal_zone_cleared_alloc_stat (struct alloc_zone * z, size_t s
                                      MEM_STAT_DECL)
{
    return ggc_internal_cleared_alloc_zone_stat (s, z PASS_MEM_STAT);
}

static inline void *
ggc_internal_zone_vec_alloc_stat (struct alloc_zone * z, size_t s, size_t n
                                  MEM_STAT_DECL)
{
    return ggc_internal_alloc_zone_stat (s * n, z PASS_MEM_STAT);
}


#else

static inline void *
ggc_internal_zone_alloc_stat (struct alloc_zone * z ATTRIBUTE_UNUSED,
                              size_t s MEM_STAT_DECL)
{
    return ggc_internal_alloc_stat (s PASS_MEM_STAT);
}

static inline void *
ggc_internal_zone_cleared_alloc_stat (struct alloc_zone * z ATTRIBUTE_UNUSED,
                                      size_t s MEM_STAT_DECL)
{
    return ggc_internal_cleared_alloc_stat (s PASS_MEM_STAT);
}

static inline void *
ggc_internal_zone_vec_alloc_stat (struct alloc_zone * z ATTRIBUTE_UNUSED,
                                  size_t s, size_t n MEM_STAT_DECL)
{
    return ggc_internal_vec_alloc_stat (s, n PASS_MEM_STAT);
}

#endif

/* Memory statistics passing versions of some allocators.  Too few of them to
   make gengtype produce them, so just define the needed ones here.  */
static inline struct rtx_def *
ggc_alloc_zone_rtx_def_stat (struct alloc_zone * z, size_t s MEM_STAT_DECL)
{
  return (struct rtx_def *) ggc_internal_zone_alloc_stat (z, s PASS_MEM_STAT);
}

static inline union tree_node *
ggc_alloc_zone_tree_node_stat (struct alloc_zone * z, size_t s MEM_STAT_DECL)
{
  return (union tree_node *) ggc_internal_zone_alloc_stat (z, s PASS_MEM_STAT);
}

static inline union tree_node *
ggc_alloc_zone_cleared_tree_node_stat (struct alloc_zone * z, size_t s
                                       MEM_STAT_DECL)
{
  return (union tree_node *)
    ggc_internal_zone_cleared_alloc_stat (z, s PASS_MEM_STAT);
}

static inline union gimple_statement_d *
ggc_alloc_cleared_gimple_statement_d_stat (size_t s MEM_STAT_DECL)
{
  return (union gimple_statement_d *)
    ggc_internal_cleared_alloc_stat (s PASS_MEM_STAT);
}

#endif