ggc.h

/* Garbage collection for the GNU compiler.

   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007,
   2008, 2009 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 */
extern const char digit_vector[];	/* "0" .. "9" */
#define digit_string(d) (digit_vector + ((d) * 2))

/* Internal functions and data structures used by the GTY
   machinery.  */

/* 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 *);

/* Mark the entries in the string pool.  */
extern void ggc_mark_stringpool	(void);

/* Purge the entries in the string pool.  */
extern void ggc_purge_stringpool (void);

/* Call ggc_set_mark on all the roots.  */

extern void ggc_mark_roots (void);

/* Save and restore the string pool entries for PCH.  */

extern void gt_pch_save_stringpool (void);
extern void gt_pch_fixup_stringpool (void);
extern void gt_pch_restore_stringpool (void);

/* PCH and GGC handling for strings, mostly trivial.  */

extern void gt_pch_p_S (void *, void *, gt_pointer_operator, void *);
extern void gt_pch_n_S (const void *);
extern void gt_ggc_m_S (const void *);

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

/* A GC implementation must provide these functions.  They are internal
   to the GC system.  */

/* Forward declare the zone structure.  Only ggc_zone implements this.  */
struct alloc_zone;

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

/* Start a new GGC zone.  */
extern struct alloc_zone *new_ggc_zone (const char *);

/* Free a complete GGC zone, destroying everything in it.  */
extern void destroy_ggc_zone (struct alloc_zone *);

struct ggc_pch_data;

/* Return a new ggc_pch_data structure.  */
extern struct ggc_pch_data *init_ggc_pch (void);

/* The second parameter and third parameters give the address and size
   of an object.  Update the ggc_pch_data structure with as much of
   that information as is necessary. The bool argument should be true
   if the object is a string.  */
extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t, bool,
				  enum gt_types_enum);

/* Return the total size of the data to be written to hold all
   the objects previously passed to ggc_pch_count_object.  */
extern size_t ggc_pch_total_size (struct ggc_pch_data *);

/* The objects, when read, will most likely be at the address
   in the second parameter.  */
extern void ggc_pch_this_base (struct ggc_pch_data *, void *);

/* Assuming that the objects really do end up at the address
   passed to ggc_pch_this_base, return the address of this object.
   The bool argument should be true if the object is a string.  */
extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t, bool,
				   enum gt_types_enum);

/* Write out any initial information required.  */
extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
/* Write out this object, including any padding.  The last argument should be
   true if the object is a string.  */
extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
				  void *, size_t, bool);
/* All objects have been written, write out any final information
   required.  */
extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);

/* A PCH file has just been read in at the address specified second
   parameter.  Set up the GC implementation for the new objects.  */
extern void ggc_pch_read (FILE *, void *);


/* Allocation.  */

/* When set, ggc_collect will do collection.  */
extern bool ggc_force_collect;

/* 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;

/* The internal primitive.  */
extern void *ggc_alloc_stat (size_t MEM_STAT_DECL);
#define ggc_alloc(s) ggc_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)
/* Like ggc_alloc, but allocates cleared memory.  */
extern void *ggc_alloc_cleared_stat (size_t MEM_STAT_DECL);
#define ggc_alloc_cleared(s) ggc_alloc_cleared_stat (s MEM_STAT_INFO)
/* Resize a block.  */
extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);
#define ggc_realloc(s,z) ggc_realloc_stat (s,z MEM_STAT_INFO)
/* Like ggc_alloc_cleared, but performs a multiplication.  */
extern void *ggc_calloc (size_t, size_t);
/* 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);

/* Type-safe, C++-friendly versions of ggc_alloc() and gcc_calloc().  */
#define GGC_NEW(T)		((T *) ggc_alloc (sizeof (T)))
#define GGC_CNEW(T)		((T *) ggc_alloc_cleared (sizeof (T)))
#define GGC_NEWVEC(T, N)	((T *) ggc_alloc ((N) * sizeof(T)))
#define GGC_CNEWVEC(T, N)	((T *) ggc_alloc_cleared ((N) * sizeof(T)))
#define GGC_RESIZEVEC(T, P, N)  ((T *) ggc_realloc ((P), (N) * sizeof (T)))
#define GGC_NEWVAR(T, S)	((T *) ggc_alloc ((S)))
#define GGC_CNEWVAR(T, S)	((T *) ggc_alloc_cleared ((S)))
#define GGC_RESIZEVAR(T, P, N)  ((T *) ggc_realloc ((P), (N)))

#define ggc_alloc_rtvec(NELT)						 \
  ((rtvec) ggc_alloc_zone (sizeof (struct rtvec_def) + ((NELT) - 1)	 \
			   * sizeof (rtx), &rtl_zone))

#define ggc_alloc_tree(LENGTH) ((tree) ggc_alloc_zone (LENGTH, &tree_zone))

#define htab_create_ggc(SIZE, HASH, EQ, DEL) \
  htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, ggc_free)

#define splay_tree_new_ggc(COMPARE)					 \
  splay_tree_new_with_allocator (COMPARE, NULL, NULL,			 \
                                 &ggc_splay_alloc, &ggc_splay_dont_free, \
				 NULL)
extern void *ggc_splay_alloc (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 (const char *contents, int length);

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

/* 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 *);

/* Return the number of bytes allocated at the indicated address.  */
extern size_t ggc_get_size (const void *);

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

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

/* This structure contains the statistics common to all collectors.
   Particular collectors can extend this structure.  */
typedef struct ggc_statistics
{
  /* At present, we don't really gather any interesting statistics.  */
  int unused;
} ggc_statistics;

/* Used by the various collectors to gather and print statistics that
   do not depend on the collector in use.  */
extern void ggc_print_common_statistics (FILE *, ggc_statistics *);

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

/* Heuristics.  */
extern int ggc_min_expand_heuristic (void);
extern int ggc_min_heapsize_heuristic (void);
extern void init_ggc_heuristics (void);

/* Zone collection.  */
#if defined (GGC_ZONE) && !defined (GENERATOR_FILE)

/* 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;

/* Allocate an object into the specified allocation zone.  */
extern void *ggc_alloc_zone_stat (size_t, struct alloc_zone * MEM_STAT_DECL);
# define ggc_alloc_zone(s,z) ggc_alloc_zone_stat (s,z MEM_STAT_INFO)
# define ggc_alloc_zone_pass_stat(s,z) ggc_alloc_zone_stat (s,z PASS_MEM_STAT)
#else

# define ggc_alloc_zone(s, z) ggc_alloc (s)
# define ggc_alloc_zone_pass_stat(s, z) ggc_alloc_stat (s PASS_MEM_STAT)

#endif

#endif