libguile/gc.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_GC_H
   4 #define SCM_GC_H
   5
   6 /* Copyright (C) 1995,1996,1998,1999,2000,2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 3 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  21  * 02110-1301 USA
  22  */
  23
  24 \f
  25
  26 #include "libguile/__scm.h"
  27
  28 #include "libguile/hooks.h"
  29 #include "libguile/threads.h"
  30
  31 \f
  32 typedef struct scm_t_cell
  33 {
  34   SCM word_0;
  35   SCM word_1;
  36 } scm_t_cell;
  37
  38 /* Cray machines have pointers that are incremented once for each
  39  * word, rather than each byte, the 3 most significant bits encode the
  40  * byte within the word.  The following macros deal with this by
  41  * storing the native Cray pointers like the ones that looks like scm
  42  * expects.  This is done for any pointers that point to a cell,
  43  * pointers to scm_vector elts, functions, &c are not munged.
  44  */
  45 #ifdef _UNICOS
  46 #  define SCM2PTR(x) ((scm_t_cell *) (SCM_UNPACK (x) >> 3))
  47 #  define PTR2SCM(x) (SCM_PACK (((scm_t_bits) (x)) << 3))
  48 #else
  49 #  define SCM2PTR(x) ((scm_t_cell *) (SCM_UNPACK (x)))
  50 #  define PTR2SCM(x) (SCM_PACK ((scm_t_bits) (x)))
  51 #endif /* def _UNICOS */
  52
  53
  54
  55 /* Low level cell data accessing macros.  These macros should only be used
  56  * from within code related to garbage collection issues, since they will
  57  * never check the cells they are applied to - not even if guile is compiled
  58  * in debug mode.  In particular these macros will even work for free cells,
  59  * which should never be encountered by user code.  */
  60
  61 #define SCM_GC_CELL_OBJECT(x, n) (((SCM *)SCM2PTR (x)) [n])
  62 #define SCM_GC_CELL_WORD(x, n)   (SCM_UNPACK (SCM_GC_CELL_OBJECT ((x), (n))))
  63
  64 #define SCM_GC_SET_CELL_OBJECT(x, n, v) ((((SCM *)SCM2PTR (x)) [n]) = (v))
  65 #define SCM_GC_SET_CELL_WORD(x, n, v)  \
  66   (SCM_GC_SET_CELL_OBJECT ((x), (n), SCM_PACK (v)))
  67
  68 #define SCM_GC_CELL_TYPE(x) (SCM_GC_CELL_OBJECT ((x), 0))
  69
  70
  71 /* Except for the garbage collector, no part of guile should ever run over a
  72  * free cell.  Thus, if guile is compiled in debug mode the SCM_CELL_* and
  73  * SCM_SET_CELL_* macros below report an error if they are applied to a free
  74  * cell.  Some other plausibility checks are also performed.  However, if
  75  * guile is not compiled in debug mode, there won't be any time penalty at all
  76  * when using these macros.  */
  77
  78 #if (SCM_DEBUG_CELL_ACCESSES == 1)
  79 #  define SCM_VALIDATE_CELL(cell, expr) (scm_assert_cell_valid (cell), (expr))
  80 #else
  81 #  define SCM_VALIDATE_CELL(cell, expr) (expr)
  82 #endif
  83
  84 #define SCM_CELL_WORD(x, n) \
  85   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_WORD ((x), (n)))
  86 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD ((x), 0)
  87 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD ((x), 1)
  88 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD ((x), 2)
  89 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD ((x), 3)
  90
  91 #define SCM_CELL_OBJECT(x, n) \
  92   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_OBJECT ((x), (n)))
  93 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT ((x), 0)
  94 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT ((x), 1)
  95 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT ((x), 2)
  96 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT ((x), 3)
  97
  98 #define SCM_SET_CELL_WORD(x, n, v) \
  99   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_WORD ((x), (n), (v)))
 100 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD ((x), 0, (v))
 101 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD ((x), 1, (v))
 102 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD ((x), 2, (v))
 103 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD ((x), 3, (v))
 104
 105 #define SCM_SET_CELL_OBJECT(x, n, v) \
 106   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_OBJECT ((x), (n), (v)))
 107 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT ((x), 0, (v))
 108 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT ((x), 1, (v))
 109 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT ((x), 2, (v))
 110 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT ((x), 3, (v))
 111
 112 #define SCM_CELL_OBJECT_LOC(x, n) (SCM_VALIDATE_CELL((x), &SCM_GC_CELL_OBJECT ((x), (n))))
 113 #define SCM_CARLOC(x)             (SCM_CELL_OBJECT_LOC ((x), 0))
 114 #define SCM_CDRLOC(x)             (SCM_CELL_OBJECT_LOC ((x), 1))
 115
 116 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 117 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 ((x), (t))
 118
 119
 120 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 121 /* Set this to != 0 if every cell that is accessed shall be checked:
 122  */
 123 SCM_API int scm_debug_cell_accesses_p;
 124 SCM_API int scm_expensive_debug_cell_accesses_p;
 125 SCM_API int scm_debug_cells_gc_interval ;
 126 SCM_API void scm_i_expensive_validation_check (SCM cell);
 127 #endif
 128
 129 SCM_INTERNAL scm_i_pthread_mutex_t scm_i_gc_admin_mutex;
 130
 131 #define scm_gc_running_p  0
 132 SCM_INTERNAL scm_i_pthread_mutex_t scm_i_sweep_mutex;
 133
 134 #ifdef __ia64__
 135 void *scm_ia64_register_backing_store_base (void);
 136 void *scm_ia64_ar_bsp (const void *);
 137 #endif
 138
 139 \f
 140
 141 SCM_API unsigned long scm_gc_ports_collected;
 142
 143 SCM_API SCM scm_after_gc_hook;
 144
 145 SCM_API scm_t_c_hook scm_before_gc_c_hook;
 146 SCM_API scm_t_c_hook scm_before_mark_c_hook;
 147 SCM_API scm_t_c_hook scm_before_sweep_c_hook;
 148 SCM_API scm_t_c_hook scm_after_sweep_c_hook;
 149 SCM_API scm_t_c_hook scm_after_gc_c_hook;
 150
 151 \f
 152
 153 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 154 SCM_API void scm_assert_cell_valid (SCM);
 155 #endif
 156
 157 SCM_API SCM scm_set_debug_cell_accesses_x (SCM flag);
 158
 159
 160 SCM_API SCM scm_object_address (SCM obj);
 161 SCM_API SCM scm_gc_enable (void);
 162 SCM_API SCM scm_gc_disable (void);
 163 SCM_API SCM scm_gc_dump (void);
 164 SCM_API SCM scm_gc_stats (void);
 165 SCM_API SCM scm_gc_live_object_stats (void);
 166 SCM_API SCM scm_gc (void);
 167 SCM_INTERNAL void scm_i_gc (const char *what);
 168 SCM_API void scm_gc_mark (SCM p);
 169 SCM_API void scm_gc_sweep (void);
 170
 171 SCM_API void *scm_malloc (size_t size) SCM_MALLOC;
 172 SCM_API void *scm_calloc (size_t size) SCM_MALLOC;
 173 SCM_API void *scm_realloc (void *mem, size_t size);
 174 SCM_API char *scm_strdup (const char *str) SCM_MALLOC;
 175 SCM_API char *scm_strndup (const char *str, size_t n) SCM_MALLOC;
 176 SCM_API void scm_gc_register_collectable_memory (void *mem, size_t size,
 177                                                  const char *what);
 178 SCM_API void scm_gc_unregister_collectable_memory (void *mem, size_t size,
 179                                                    const char *what);
 180 SCM_API void *scm_gc_malloc_pointerless (size_t size, const char *what)
 181   SCM_MALLOC;
 182 SCM_API void *scm_gc_calloc (size_t size, const char *what)
 183   SCM_MALLOC;
 184 SCM_API void *scm_gc_malloc (size_t size, const char *what)
 185   SCM_MALLOC;
 186 SCM_API void *scm_gc_realloc (void *mem, size_t old_size,
 187                               size_t new_size, const char *what);
 188 SCM_API void scm_gc_free (void *mem, size_t size, const char *what);
 189 SCM_API char *scm_gc_strdup (const char *str, const char *what)
 190   SCM_MALLOC;
 191 SCM_API char *scm_gc_strndup (const char *str, size_t n, const char *what)
 192   SCM_MALLOC;
 193
 194 SCM_API void scm_remember_upto_here_1 (SCM obj);
 195 SCM_API void scm_remember_upto_here_2 (SCM obj1, SCM obj2);
 196 SCM_API void scm_remember_upto_here (SCM obj1, ...);
 197
 198 /* In GCC we can force a reference to an SCM by making it an input to an
 199    empty asm.  This avoids the code size and slowdown of an actual function
 200    call.  Unfortunately there doesn't seem to be any way to do the varargs
 201    scm_remember_upto_here like this.
 202
 203    __volatile__ ensures nothing will be moved across the asm, and it won't
 204    be optimized away (or only if proved unreachable).  Constraint "g" can be
 205    used on all processors and allows any memory or general register (or
 206    immediate) operand.  The actual asm syntax doesn't matter, we don't want
 207    to use it, just ensure the operand is still alive.  See "Extended Asm" in
 208    the GCC manual for more.  */
 209
 210 #ifdef __GNUC__
 211 #define scm_remember_upto_here_1(x)             \
 212   do {                                          \
 213     __asm__ __volatile__ ("" : : "g" (x));      \
 214   } while (0)
 215 #define scm_remember_upto_here_2(x, y)          \
 216   do {                                          \
 217     scm_remember_upto_here_1 (x);               \
 218     scm_remember_upto_here_1 (y);               \
 219   } while (0)
 220 #endif
 221
 222 SCM_API SCM scm_return_first (SCM elt, ...);
 223 SCM_API int scm_return_first_int (int x, ...);
 224 SCM_API SCM scm_permanent_object (SCM obj);
 225 SCM_API SCM scm_gc_protect_object (SCM obj);
 226 SCM_API SCM scm_gc_unprotect_object (SCM obj);
 227 SCM_API void scm_gc_register_root (SCM *p);
 228 SCM_API void scm_gc_unregister_root (SCM *p);
 229 SCM_API void scm_gc_register_roots (SCM *b, unsigned long n);
 230 SCM_API void scm_gc_unregister_roots (SCM *b, unsigned long n);
 231 SCM_API SCM scm_protects;
 232 SCM_INTERNAL void scm_storage_prehistory (void);
 233 SCM_INTERNAL void scm_init_gc_protect_object (void);
 234 SCM_INTERNAL void scm_init_gc (void);
 235
 236 #endif  /* SCM_GC_H */
 237
 238 /*
 239   Local Variables:
 240   c-file-style: "gnu"
 241   End:
 242 */