| 1 | /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2003, 2006, 2008, 2009, 2010 Free Software Foundation, Inc. |
| 2 | * |
| 3 | * This library is free software; you can redistribute it and/or |
| 4 | * modify it under the terms of the GNU Lesser General Public License |
| 5 | * as published by the Free Software Foundation; either version 3 of |
| 6 | * the License, or (at your option) any later version. |
| 7 | * |
| 8 | * This library is distributed in the hope that it will be useful, but |
| 9 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 11 | * Lesser General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU Lesser General Public |
| 14 | * License along with this library; if not, write to the Free Software |
| 15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 16 | * 02110-1301 USA |
| 17 | */ |
| 18 | |
| 19 | /* #define DEBUGINFO */ |
| 20 | |
| 21 | #ifdef HAVE_CONFIG_H |
| 22 | # include <config.h> |
| 23 | #endif |
| 24 | |
| 25 | #include "libguile/gen-scmconfig.h" |
| 26 | |
| 27 | #include <stdio.h> |
| 28 | #include <errno.h> |
| 29 | #include <string.h> |
| 30 | |
| 31 | #ifdef __ia64__ |
| 32 | #include <ucontext.h> |
| 33 | extern unsigned long * __libc_ia64_register_backing_store_base; |
| 34 | #endif |
| 35 | |
| 36 | #include "libguile/_scm.h" |
| 37 | #include "libguile/eval.h" |
| 38 | #include "libguile/stime.h" |
| 39 | #include "libguile/stackchk.h" |
| 40 | #include "libguile/struct.h" |
| 41 | #include "libguile/smob.h" |
| 42 | #include "libguile/arrays.h" |
| 43 | #include "libguile/async.h" |
| 44 | #include "libguile/ports.h" |
| 45 | #include "libguile/root.h" |
| 46 | #include "libguile/strings.h" |
| 47 | #include "libguile/vectors.h" |
| 48 | #include "libguile/weaks.h" |
| 49 | #include "libguile/hashtab.h" |
| 50 | #include "libguile/tags.h" |
| 51 | |
| 52 | #include "libguile/private-gc.h" |
| 53 | #include "libguile/validate.h" |
| 54 | #include "libguile/deprecation.h" |
| 55 | #include "libguile/gc.h" |
| 56 | #include "libguile/dynwind.h" |
| 57 | |
| 58 | #include "libguile/bdw-gc.h" |
| 59 | |
| 60 | #ifdef GUILE_DEBUG_MALLOC |
| 61 | #include "libguile/debug-malloc.h" |
| 62 | #endif |
| 63 | |
| 64 | #ifdef HAVE_MALLOC_H |
| 65 | #include <malloc.h> |
| 66 | #endif |
| 67 | |
| 68 | #ifdef HAVE_UNISTD_H |
| 69 | #include <unistd.h> |
| 70 | #endif |
| 71 | |
| 72 | /* Lock this mutex before doing lazy sweeping. |
| 73 | */ |
| 74 | scm_i_pthread_mutex_t scm_i_sweep_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER; |
| 75 | |
| 76 | /* Set this to != 0 if every cell that is accessed shall be checked: |
| 77 | */ |
| 78 | int scm_debug_cell_accesses_p = 0; |
| 79 | int scm_expensive_debug_cell_accesses_p = 0; |
| 80 | |
| 81 | /* Set this to 0 if no additional gc's shall be performed, otherwise set it to |
| 82 | * the number of cell accesses after which a gc shall be called. |
| 83 | */ |
| 84 | int scm_debug_cells_gc_interval = 0; |
| 85 | |
| 86 | /* |
| 87 | Global variable, so you can switch it off at runtime by setting |
| 88 | scm_i_cell_validation_already_running. |
| 89 | */ |
| 90 | int scm_i_cell_validation_already_running ; |
| 91 | |
| 92 | static SCM protects; |
| 93 | |
| 94 | |
| 95 | #if (SCM_DEBUG_CELL_ACCESSES == 1) |
| 96 | |
| 97 | |
| 98 | /* |
| 99 | |
| 100 | Assert that the given object is a valid reference to a valid cell. This |
| 101 | test involves to determine whether the object is a cell pointer, whether |
| 102 | this pointer actually points into a heap segment and whether the cell |
| 103 | pointed to is not a free cell. Further, additional garbage collections may |
| 104 | get executed after a user defined number of cell accesses. This helps to |
| 105 | find places in the C code where references are dropped for extremely short |
| 106 | periods. |
| 107 | |
| 108 | */ |
| 109 | void |
| 110 | scm_i_expensive_validation_check (SCM cell) |
| 111 | { |
| 112 | /* If desired, perform additional garbage collections after a user |
| 113 | * defined number of cell accesses. |
| 114 | */ |
| 115 | if (scm_debug_cells_gc_interval) |
| 116 | { |
| 117 | static unsigned int counter = 0; |
| 118 | |
| 119 | if (counter != 0) |
| 120 | { |
| 121 | --counter; |
| 122 | } |
| 123 | else |
| 124 | { |
| 125 | counter = scm_debug_cells_gc_interval; |
| 126 | scm_gc (); |
| 127 | } |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | void |
| 132 | scm_assert_cell_valid (SCM cell) |
| 133 | { |
| 134 | if (!scm_i_cell_validation_already_running && scm_debug_cell_accesses_p) |
| 135 | { |
| 136 | scm_i_cell_validation_already_running = 1; /* set to avoid recursion */ |
| 137 | |
| 138 | /* |
| 139 | During GC, no user-code should be run, and the guile core |
| 140 | should use non-protected accessors. |
| 141 | */ |
| 142 | if (scm_gc_running_p) |
| 143 | return; |
| 144 | |
| 145 | /* |
| 146 | Only scm_in_heap_p and rescanning the heap is wildly |
| 147 | expensive. |
| 148 | */ |
| 149 | if (scm_expensive_debug_cell_accesses_p) |
| 150 | scm_i_expensive_validation_check (cell); |
| 151 | |
| 152 | scm_i_cell_validation_already_running = 0; /* re-enable */ |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | |
| 157 | |
| 158 | SCM_DEFINE (scm_set_debug_cell_accesses_x, "set-debug-cell-accesses!", 1, 0, 0, |
| 159 | (SCM flag), |
| 160 | "If @var{flag} is @code{#f}, cell access checking is disabled.\n" |
| 161 | "If @var{flag} is @code{#t}, cheap cell access checking is enabled,\n" |
| 162 | "but no additional calls to garbage collection are issued.\n" |
| 163 | "If @var{flag} is a number, strict cell access checking is enabled,\n" |
| 164 | "with an additional garbage collection after the given\n" |
| 165 | "number of cell accesses.\n" |
| 166 | "This procedure only exists when the compile-time flag\n" |
| 167 | "@code{SCM_DEBUG_CELL_ACCESSES} was set to 1.") |
| 168 | #define FUNC_NAME s_scm_set_debug_cell_accesses_x |
| 169 | { |
| 170 | if (scm_is_false (flag)) |
| 171 | { |
| 172 | scm_debug_cell_accesses_p = 0; |
| 173 | } |
| 174 | else if (scm_is_eq (flag, SCM_BOOL_T)) |
| 175 | { |
| 176 | scm_debug_cells_gc_interval = 0; |
| 177 | scm_debug_cell_accesses_p = 1; |
| 178 | scm_expensive_debug_cell_accesses_p = 0; |
| 179 | } |
| 180 | else |
| 181 | { |
| 182 | scm_debug_cells_gc_interval = scm_to_signed_integer (flag, 0, INT_MAX); |
| 183 | scm_debug_cell_accesses_p = 1; |
| 184 | scm_expensive_debug_cell_accesses_p = 1; |
| 185 | } |
| 186 | return SCM_UNSPECIFIED; |
| 187 | } |
| 188 | #undef FUNC_NAME |
| 189 | |
| 190 | |
| 191 | #endif /* SCM_DEBUG_CELL_ACCESSES == 1 */ |
| 192 | |
| 193 | \f |
| 194 | /* Hooks. */ |
| 195 | scm_t_c_hook scm_before_gc_c_hook; |
| 196 | scm_t_c_hook scm_before_mark_c_hook; |
| 197 | scm_t_c_hook scm_before_sweep_c_hook; |
| 198 | scm_t_c_hook scm_after_sweep_c_hook; |
| 199 | scm_t_c_hook scm_after_gc_c_hook; |
| 200 | |
| 201 | |
| 202 | /* GC Statistics Keeping |
| 203 | */ |
| 204 | unsigned long scm_gc_ports_collected = 0; |
| 205 | |
| 206 | static unsigned long protected_obj_count = 0; |
| 207 | |
| 208 | |
| 209 | SCM_SYMBOL (sym_cells_allocated, "cells-allocated"); |
| 210 | SCM_SYMBOL (sym_heap_size, "heap-size"); |
| 211 | SCM_SYMBOL (sym_heap_free_size, "heap-free-size"); |
| 212 | SCM_SYMBOL (sym_heap_total_allocated, "heap-total-allocated"); |
| 213 | SCM_SYMBOL (sym_mallocated, "bytes-malloced"); |
| 214 | SCM_SYMBOL (sym_mtrigger, "gc-malloc-threshold"); |
| 215 | SCM_SYMBOL (sym_heap_segments, "cell-heap-segments"); |
| 216 | SCM_SYMBOL (sym_gc_time_taken, "gc-time-taken"); |
| 217 | SCM_SYMBOL (sym_gc_mark_time_taken, "gc-mark-time-taken"); |
| 218 | SCM_SYMBOL (sym_times, "gc-times"); |
| 219 | SCM_SYMBOL (sym_cells_marked, "cells-marked"); |
| 220 | SCM_SYMBOL (sym_cells_marked_conservatively, "cells-marked-conservatively"); |
| 221 | SCM_SYMBOL (sym_cells_swept, "cells-swept"); |
| 222 | SCM_SYMBOL (sym_malloc_yield, "malloc-yield"); |
| 223 | SCM_SYMBOL (sym_cell_yield, "cell-yield"); |
| 224 | SCM_SYMBOL (sym_protected_objects, "protected-objects"); |
| 225 | SCM_SYMBOL (sym_total_cells_allocated, "total-cells-allocated"); |
| 226 | |
| 227 | |
| 228 | /* Number of calls to SCM_NEWCELL since startup. */ |
| 229 | unsigned scm_newcell_count; |
| 230 | unsigned scm_newcell2_count; |
| 231 | |
| 232 | |
| 233 | /* {Scheme Interface to GC} |
| 234 | */ |
| 235 | static SCM |
| 236 | tag_table_to_type_alist (void *closure, SCM key, SCM val, SCM acc) |
| 237 | { |
| 238 | if (scm_is_integer (key)) |
| 239 | { |
| 240 | int c_tag = scm_to_int (key); |
| 241 | |
| 242 | char const * name = scm_i_tag_name (c_tag); |
| 243 | if (name != NULL) |
| 244 | { |
| 245 | key = scm_from_locale_string (name); |
| 246 | } |
| 247 | else |
| 248 | { |
| 249 | char s[100]; |
| 250 | sprintf (s, "tag %d", c_tag); |
| 251 | key = scm_from_locale_string (s); |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | return scm_cons (scm_cons (key, val), acc); |
| 256 | } |
| 257 | |
| 258 | SCM_DEFINE (scm_gc_live_object_stats, "gc-live-object-stats", 0, 0, 0, |
| 259 | (), |
| 260 | "Return an alist of statistics of the current live objects. ") |
| 261 | #define FUNC_NAME s_scm_gc_live_object_stats |
| 262 | { |
| 263 | SCM tab = scm_make_hash_table (scm_from_int (57)); |
| 264 | SCM alist; |
| 265 | |
| 266 | alist |
| 267 | = scm_internal_hash_fold (&tag_table_to_type_alist, NULL, SCM_EOL, tab); |
| 268 | |
| 269 | return alist; |
| 270 | } |
| 271 | #undef FUNC_NAME |
| 272 | |
| 273 | extern int scm_gc_malloc_yield_percentage; |
| 274 | SCM_DEFINE (scm_gc_stats, "gc-stats", 0, 0, 0, |
| 275 | (), |
| 276 | "Return an association list of statistics about Guile's current\n" |
| 277 | "use of storage.\n") |
| 278 | #define FUNC_NAME s_scm_gc_stats |
| 279 | { |
| 280 | SCM answer; |
| 281 | size_t heap_size, free_bytes, bytes_since_gc, total_bytes; |
| 282 | size_t gc_times; |
| 283 | |
| 284 | heap_size = GC_get_heap_size (); |
| 285 | free_bytes = GC_get_free_bytes (); |
| 286 | bytes_since_gc = GC_get_bytes_since_gc (); |
| 287 | total_bytes = GC_get_total_bytes (); |
| 288 | gc_times = GC_gc_no; |
| 289 | |
| 290 | /* njrev: can any of these scm_cons's or scm_list_n signal a memory |
| 291 | error? If so we need a frame here. */ |
| 292 | answer = |
| 293 | scm_list_n (scm_cons (sym_gc_time_taken, SCM_INUM0), |
| 294 | #if 0 |
| 295 | scm_cons (sym_cells_allocated, |
| 296 | scm_from_ulong (local_scm_cells_allocated)), |
| 297 | scm_cons (sym_mallocated, |
| 298 | scm_from_ulong (local_scm_mallocated)), |
| 299 | scm_cons (sym_mtrigger, |
| 300 | scm_from_ulong (local_scm_mtrigger)), |
| 301 | scm_cons (sym_gc_mark_time_taken, |
| 302 | scm_from_ulong (local_scm_gc_mark_time_taken)), |
| 303 | scm_cons (sym_cells_marked, |
| 304 | scm_from_double (local_scm_gc_cells_marked)), |
| 305 | scm_cons (sym_cells_swept, |
| 306 | scm_from_double (local_scm_gc_cells_swept)), |
| 307 | scm_cons (sym_malloc_yield, |
| 308 | scm_from_long (local_scm_gc_malloc_yield_percentage)), |
| 309 | scm_cons (sym_cell_yield, |
| 310 | scm_from_long (local_scm_gc_cell_yield_percentage)), |
| 311 | scm_cons (sym_heap_segments, heap_segs), |
| 312 | #endif |
| 313 | scm_cons (sym_heap_size, scm_from_size_t (heap_size)), |
| 314 | scm_cons (sym_heap_free_size, scm_from_size_t (free_bytes)), |
| 315 | scm_cons (sym_heap_total_allocated, |
| 316 | scm_from_size_t (total_bytes)), |
| 317 | scm_cons (sym_protected_objects, |
| 318 | scm_from_ulong (protected_obj_count)), |
| 319 | scm_cons (sym_times, scm_from_size_t (gc_times)), |
| 320 | SCM_UNDEFINED); |
| 321 | |
| 322 | return answer; |
| 323 | } |
| 324 | #undef FUNC_NAME |
| 325 | |
| 326 | |
| 327 | SCM_DEFINE (scm_gc_dump, "gc-dump", 0, 0, 0, |
| 328 | (void), |
| 329 | "Dump information about the garbage collector's internal data " |
| 330 | "structures and memory usage to the standard output.") |
| 331 | #define FUNC_NAME s_scm_gc_dump |
| 332 | { |
| 333 | GC_dump (); |
| 334 | |
| 335 | return SCM_UNSPECIFIED; |
| 336 | } |
| 337 | #undef FUNC_NAME |
| 338 | |
| 339 | |
| 340 | SCM_DEFINE (scm_object_address, "object-address", 1, 0, 0, |
| 341 | (SCM obj), |
| 342 | "Return an integer that for the lifetime of @var{obj} is uniquely\n" |
| 343 | "returned by this function for @var{obj}") |
| 344 | #define FUNC_NAME s_scm_object_address |
| 345 | { |
| 346 | return scm_from_ulong (SCM_UNPACK (obj)); |
| 347 | } |
| 348 | #undef FUNC_NAME |
| 349 | |
| 350 | |
| 351 | SCM_DEFINE (scm_gc_disable, "gc-disable", 0, 0, 0, |
| 352 | (), |
| 353 | "Disables the garbage collector. Nested calls are permitted. " |
| 354 | "GC is re-enabled once @code{gc-enable} has been called the " |
| 355 | "same number of times @code{gc-disable} was called.") |
| 356 | #define FUNC_NAME s_scm_gc_disable |
| 357 | { |
| 358 | GC_disable (); |
| 359 | return SCM_UNSPECIFIED; |
| 360 | } |
| 361 | #undef FUNC_NAME |
| 362 | |
| 363 | SCM_DEFINE (scm_gc_enable, "gc-enable", 0, 0, 0, |
| 364 | (), |
| 365 | "Enables the garbage collector.") |
| 366 | #define FUNC_NAME s_scm_gc_enable |
| 367 | { |
| 368 | GC_enable (); |
| 369 | return SCM_UNSPECIFIED; |
| 370 | } |
| 371 | #undef FUNC_NAME |
| 372 | |
| 373 | |
| 374 | SCM_DEFINE (scm_gc, "gc", 0, 0, 0, |
| 375 | (), |
| 376 | "Scans all of SCM objects and reclaims for further use those that are\n" |
| 377 | "no longer accessible.") |
| 378 | #define FUNC_NAME s_scm_gc |
| 379 | { |
| 380 | scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex); |
| 381 | scm_i_gc ("call"); |
| 382 | /* njrev: It looks as though other places, e.g. scm_realloc, |
| 383 | can call scm_i_gc without acquiring the sweep mutex. Does this |
| 384 | matter? Also scm_i_gc (or its descendants) touch the |
| 385 | scm_sys_protects, which are protected in some cases |
| 386 | (e.g. scm_permobjs above in scm_gc_stats) by a critical section, |
| 387 | not by the sweep mutex. Shouldn't all the GC-relevant objects be |
| 388 | protected in the same way? */ |
| 389 | scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex); |
| 390 | scm_c_hook_run (&scm_after_gc_c_hook, 0); |
| 391 | return SCM_UNSPECIFIED; |
| 392 | } |
| 393 | #undef FUNC_NAME |
| 394 | |
| 395 | void |
| 396 | scm_i_gc (const char *what) |
| 397 | { |
| 398 | GC_gcollect (); |
| 399 | } |
| 400 | |
| 401 | |
| 402 | \f |
| 403 | /* {GC Protection Helper Functions} |
| 404 | */ |
| 405 | |
| 406 | |
| 407 | /* |
| 408 | * If within a function you need to protect one or more scheme objects from |
| 409 | * garbage collection, pass them as parameters to one of the |
| 410 | * scm_remember_upto_here* functions below. These functions don't do |
| 411 | * anything, but since the compiler does not know that they are actually |
| 412 | * no-ops, it will generate code that calls these functions with the given |
| 413 | * parameters. Therefore, you can be sure that the compiler will keep those |
| 414 | * scheme values alive (on the stack or in a register) up to the point where |
| 415 | * scm_remember_upto_here* is called. In other words, place the call to |
| 416 | * scm_remember_upto_here* _behind_ the last code in your function, that |
| 417 | * depends on the scheme object to exist. |
| 418 | * |
| 419 | * Example: We want to make sure that the string object str does not get |
| 420 | * garbage collected during the execution of 'some_function' in the code |
| 421 | * below, because otherwise the characters belonging to str would be freed and |
| 422 | * 'some_function' might access freed memory. To make sure that the compiler |
| 423 | * keeps str alive on the stack or in a register such that it is visible to |
| 424 | * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the |
| 425 | * call to 'some_function'. Note that this would not be necessary if str was |
| 426 | * used anyway after the call to 'some_function'. |
| 427 | * char *chars = scm_i_string_chars (str); |
| 428 | * some_function (chars); |
| 429 | * scm_remember_upto_here_1 (str); // str will be alive up to this point. |
| 430 | */ |
| 431 | |
| 432 | /* Remove any macro versions of these while defining the functions. |
| 433 | Functions are always included in the library, for upward binary |
| 434 | compatibility and in case combinations of GCC and non-GCC are used. */ |
| 435 | #undef scm_remember_upto_here_1 |
| 436 | #undef scm_remember_upto_here_2 |
| 437 | |
| 438 | void |
| 439 | scm_remember_upto_here_1 (SCM obj SCM_UNUSED) |
| 440 | { |
| 441 | /* Empty. Protects a single object from garbage collection. */ |
| 442 | } |
| 443 | |
| 444 | void |
| 445 | scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED, SCM obj2 SCM_UNUSED) |
| 446 | { |
| 447 | /* Empty. Protects two objects from garbage collection. */ |
| 448 | } |
| 449 | |
| 450 | void |
| 451 | scm_remember_upto_here (SCM obj SCM_UNUSED, ...) |
| 452 | { |
| 453 | /* Empty. Protects any number of objects from garbage collection. */ |
| 454 | } |
| 455 | |
| 456 | /* |
| 457 | These crazy functions prevent garbage collection |
| 458 | of arguments after the first argument by |
| 459 | ensuring they remain live throughout the |
| 460 | function because they are used in the last |
| 461 | line of the code block. |
| 462 | It'd be better to have a nice compiler hint to |
| 463 | aid the conservative stack-scanning GC. --03/09/00 gjb */ |
| 464 | SCM |
| 465 | scm_return_first (SCM elt, ...) |
| 466 | { |
| 467 | return elt; |
| 468 | } |
| 469 | |
| 470 | int |
| 471 | scm_return_first_int (int i, ...) |
| 472 | { |
| 473 | return i; |
| 474 | } |
| 475 | |
| 476 | |
| 477 | SCM |
| 478 | scm_permanent_object (SCM obj) |
| 479 | { |
| 480 | return (scm_gc_protect_object (obj)); |
| 481 | } |
| 482 | |
| 483 | |
| 484 | /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all |
| 485 | other references are dropped, until the object is unprotected by calling |
| 486 | scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest, |
| 487 | i. e. it is possible to protect the same object several times, but it is |
| 488 | necessary to unprotect the object the same number of times to actually get |
| 489 | the object unprotected. It is an error to unprotect an object more often |
| 490 | than it has been protected before. The function scm_protect_object returns |
| 491 | OBJ. |
| 492 | */ |
| 493 | |
| 494 | /* Implementation note: For every object X, there is a counter which |
| 495 | scm_gc_protect_object (X) increments and scm_gc_unprotect_object (X) decrements. |
| 496 | */ |
| 497 | |
| 498 | |
| 499 | |
| 500 | SCM |
| 501 | scm_gc_protect_object (SCM obj) |
| 502 | { |
| 503 | SCM handle; |
| 504 | |
| 505 | /* This critical section barrier will be replaced by a mutex. */ |
| 506 | /* njrev: Indeed; if my comment above is correct, there is the same |
| 507 | critsec/mutex inconsistency here. */ |
| 508 | SCM_CRITICAL_SECTION_START; |
| 509 | |
| 510 | handle = scm_hashq_create_handle_x (protects, obj, scm_from_int (0)); |
| 511 | SCM_SETCDR (handle, scm_sum (SCM_CDR (handle), scm_from_int (1))); |
| 512 | |
| 513 | protected_obj_count ++; |
| 514 | |
| 515 | SCM_CRITICAL_SECTION_END; |
| 516 | |
| 517 | return obj; |
| 518 | } |
| 519 | |
| 520 | |
| 521 | /* Remove any protection for OBJ established by a prior call to |
| 522 | scm_protect_object. This function returns OBJ. |
| 523 | |
| 524 | See scm_protect_object for more information. */ |
| 525 | SCM |
| 526 | scm_gc_unprotect_object (SCM obj) |
| 527 | { |
| 528 | SCM handle; |
| 529 | |
| 530 | /* This critical section barrier will be replaced by a mutex. */ |
| 531 | /* njrev: and again. */ |
| 532 | SCM_CRITICAL_SECTION_START; |
| 533 | |
| 534 | if (scm_gc_running_p) |
| 535 | { |
| 536 | fprintf (stderr, "scm_unprotect_object called during GC.\n"); |
| 537 | abort (); |
| 538 | } |
| 539 | |
| 540 | handle = scm_hashq_get_handle (protects, obj); |
| 541 | |
| 542 | if (scm_is_false (handle)) |
| 543 | { |
| 544 | fprintf (stderr, "scm_unprotect_object called on unprotected object\n"); |
| 545 | abort (); |
| 546 | } |
| 547 | else |
| 548 | { |
| 549 | SCM count = scm_difference (SCM_CDR (handle), scm_from_int (1)); |
| 550 | if (scm_is_eq (count, scm_from_int (0))) |
| 551 | scm_hashq_remove_x (protects, obj); |
| 552 | else |
| 553 | SCM_SETCDR (handle, count); |
| 554 | } |
| 555 | protected_obj_count --; |
| 556 | |
| 557 | SCM_CRITICAL_SECTION_END; |
| 558 | |
| 559 | return obj; |
| 560 | } |
| 561 | |
| 562 | void |
| 563 | scm_gc_register_root (SCM *p) |
| 564 | { |
| 565 | /* Nothing. */ |
| 566 | } |
| 567 | |
| 568 | void |
| 569 | scm_gc_unregister_root (SCM *p) |
| 570 | { |
| 571 | /* Nothing. */ |
| 572 | } |
| 573 | |
| 574 | void |
| 575 | scm_gc_register_roots (SCM *b, unsigned long n) |
| 576 | { |
| 577 | SCM *p = b; |
| 578 | for (; p < b + n; ++p) |
| 579 | scm_gc_register_root (p); |
| 580 | } |
| 581 | |
| 582 | void |
| 583 | scm_gc_unregister_roots (SCM *b, unsigned long n) |
| 584 | { |
| 585 | SCM *p = b; |
| 586 | for (; p < b + n; ++p) |
| 587 | scm_gc_unregister_root (p); |
| 588 | } |
| 589 | |
| 590 | int scm_i_terminating; |
| 591 | |
| 592 | \f |
| 593 | |
| 594 | |
| 595 | /* |
| 596 | MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC. |
| 597 | */ |
| 598 | |
| 599 | /* Get an integer from an environment variable. */ |
| 600 | int |
| 601 | scm_getenv_int (const char *var, int def) |
| 602 | { |
| 603 | char *end = 0; |
| 604 | char *val = getenv (var); |
| 605 | long res = def; |
| 606 | if (!val) |
| 607 | return def; |
| 608 | res = strtol (val, &end, 10); |
| 609 | if (end == val) |
| 610 | return def; |
| 611 | return res; |
| 612 | } |
| 613 | |
| 614 | void |
| 615 | scm_storage_prehistory () |
| 616 | { |
| 617 | GC_all_interior_pointers = 0; |
| 618 | GC_set_free_space_divisor (scm_getenv_int ("GC_FREE_SPACE_DIVISOR", 3)); |
| 619 | |
| 620 | GC_INIT (); |
| 621 | |
| 622 | #if (! ((defined GC_VERSION_MAJOR) && (GC_VERSION_MAJOR >= 7))) \ |
| 623 | && (defined SCM_I_GSC_USE_PTHREAD_THREADS) |
| 624 | /* When using GC 6.8, this call is required to initialize thread-local |
| 625 | freelists (shouldn't be necessary with GC 7.0). */ |
| 626 | GC_init (); |
| 627 | #endif |
| 628 | |
| 629 | GC_expand_hp (SCM_DEFAULT_INIT_HEAP_SIZE_2); |
| 630 | |
| 631 | /* We only need to register a displacement for those types for which the |
| 632 | higher bits of the type tag are used to store a pointer (that is, a |
| 633 | pointer to an 8-octet aligned region). For `scm_tc3_struct', this is |
| 634 | handled in `scm_alloc_struct ()'. */ |
| 635 | GC_REGISTER_DISPLACEMENT (scm_tc3_cons); |
| 636 | /* GC_REGISTER_DISPLACEMENT (scm_tc3_unused); */ |
| 637 | |
| 638 | /* Sanity check. */ |
| 639 | if (!GC_is_visible (&protects)) |
| 640 | abort (); |
| 641 | |
| 642 | scm_c_hook_init (&scm_before_gc_c_hook, 0, SCM_C_HOOK_NORMAL); |
| 643 | scm_c_hook_init (&scm_before_mark_c_hook, 0, SCM_C_HOOK_NORMAL); |
| 644 | scm_c_hook_init (&scm_before_sweep_c_hook, 0, SCM_C_HOOK_NORMAL); |
| 645 | scm_c_hook_init (&scm_after_sweep_c_hook, 0, SCM_C_HOOK_NORMAL); |
| 646 | scm_c_hook_init (&scm_after_gc_c_hook, 0, SCM_C_HOOK_NORMAL); |
| 647 | } |
| 648 | |
| 649 | scm_i_pthread_mutex_t scm_i_gc_admin_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER; |
| 650 | |
| 651 | void |
| 652 | scm_init_gc_protect_object () |
| 653 | { |
| 654 | protects = scm_c_make_hash_table (31); |
| 655 | |
| 656 | #if 0 |
| 657 | /* We can't have a cleanup handler since we have no thread to run it |
| 658 | in. */ |
| 659 | |
| 660 | #ifdef HAVE_ATEXIT |
| 661 | atexit (cleanup); |
| 662 | #else |
| 663 | #ifdef HAVE_ON_EXIT |
| 664 | on_exit (cleanup, 0); |
| 665 | #endif |
| 666 | #endif |
| 667 | |
| 668 | #endif |
| 669 | } |
| 670 | |
| 671 | \f |
| 672 | |
| 673 | SCM scm_after_gc_hook; |
| 674 | |
| 675 | static SCM gc_async; |
| 676 | |
| 677 | /* The function gc_async_thunk causes the execution of the after-gc-hook. It |
| 678 | * is run after the gc, as soon as the asynchronous events are handled by the |
| 679 | * evaluator. |
| 680 | */ |
| 681 | static SCM |
| 682 | gc_async_thunk (void) |
| 683 | { |
| 684 | scm_c_run_hook (scm_after_gc_hook, SCM_EOL); |
| 685 | return SCM_UNSPECIFIED; |
| 686 | } |
| 687 | |
| 688 | |
| 689 | /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of |
| 690 | * the garbage collection. The only purpose of this function is to mark the |
| 691 | * gc_async (which will eventually lead to the execution of the |
| 692 | * gc_async_thunk). |
| 693 | */ |
| 694 | static void * |
| 695 | mark_gc_async (void * hook_data SCM_UNUSED, |
| 696 | void *fn_data SCM_UNUSED, |
| 697 | void *data SCM_UNUSED) |
| 698 | { |
| 699 | /* If cell access debugging is enabled, the user may choose to perform |
| 700 | * additional garbage collections after an arbitrary number of cell |
| 701 | * accesses. We don't want the scheme level after-gc-hook to be performed |
| 702 | * for each of these garbage collections for the following reason: The |
| 703 | * execution of the after-gc-hook causes cell accesses itself. Thus, if the |
| 704 | * after-gc-hook was performed with every gc, and if the gc was performed |
| 705 | * after a very small number of cell accesses, then the number of cell |
| 706 | * accesses during the execution of the after-gc-hook will suffice to cause |
| 707 | * the execution of the next gc. Then, guile would keep executing the |
| 708 | * after-gc-hook over and over again, and would never come to do other |
| 709 | * things. |
| 710 | * |
| 711 | * To overcome this problem, if cell access debugging with additional |
| 712 | * garbage collections is enabled, the after-gc-hook is never run by the |
| 713 | * garbage collecter. When running guile with cell access debugging and the |
| 714 | * execution of the after-gc-hook is desired, then it is necessary to run |
| 715 | * the hook explicitly from the user code. This has the effect, that from |
| 716 | * the scheme level point of view it seems that garbage collection is |
| 717 | * performed with a much lower frequency than it actually is. Obviously, |
| 718 | * this will not work for code that depends on a fixed one to one |
| 719 | * relationship between the execution counts of the C level garbage |
| 720 | * collection hooks and the execution count of the scheme level |
| 721 | * after-gc-hook. |
| 722 | */ |
| 723 | |
| 724 | #if (SCM_DEBUG_CELL_ACCESSES == 1) |
| 725 | if (scm_debug_cells_gc_interval == 0) |
| 726 | scm_system_async_mark (gc_async); |
| 727 | #else |
| 728 | scm_system_async_mark (gc_async); |
| 729 | #endif |
| 730 | |
| 731 | return NULL; |
| 732 | } |
| 733 | |
| 734 | char const * |
| 735 | scm_i_tag_name (scm_t_bits tag) |
| 736 | { |
| 737 | if (tag >= 255) |
| 738 | { |
| 739 | int k = 0xff & (tag >> 8); |
| 740 | return (scm_smobs[k].name); |
| 741 | } |
| 742 | |
| 743 | switch (tag) /* 7 bits */ |
| 744 | { |
| 745 | case scm_tcs_struct: |
| 746 | return "struct"; |
| 747 | case scm_tcs_cons_imcar: |
| 748 | return "cons (immediate car)"; |
| 749 | case scm_tcs_cons_nimcar: |
| 750 | return "cons (non-immediate car)"; |
| 751 | case scm_tc7_foreign: |
| 752 | return "foreign"; |
| 753 | case scm_tc7_hashtable: |
| 754 | return "hashtable"; |
| 755 | case scm_tc7_fluid: |
| 756 | return "fluid"; |
| 757 | case scm_tc7_dynamic_state: |
| 758 | return "dynamic state"; |
| 759 | case scm_tc7_wvect: |
| 760 | return "weak vector"; |
| 761 | case scm_tc7_vector: |
| 762 | return "vector"; |
| 763 | case scm_tc7_number: |
| 764 | switch (tag) |
| 765 | { |
| 766 | case scm_tc16_real: |
| 767 | return "real"; |
| 768 | break; |
| 769 | case scm_tc16_big: |
| 770 | return "bignum"; |
| 771 | break; |
| 772 | case scm_tc16_complex: |
| 773 | return "complex number"; |
| 774 | break; |
| 775 | case scm_tc16_fraction: |
| 776 | return "fraction"; |
| 777 | break; |
| 778 | } |
| 779 | break; |
| 780 | case scm_tc7_string: |
| 781 | return "string"; |
| 782 | break; |
| 783 | case scm_tc7_stringbuf: |
| 784 | return "string buffer"; |
| 785 | break; |
| 786 | case scm_tc7_symbol: |
| 787 | return "symbol"; |
| 788 | break; |
| 789 | case scm_tc7_variable: |
| 790 | return "variable"; |
| 791 | break; |
| 792 | case scm_tc7_gsubr: |
| 793 | return "gsubr"; |
| 794 | break; |
| 795 | case scm_tc7_port: |
| 796 | return "port"; |
| 797 | break; |
| 798 | case scm_tc7_smob: |
| 799 | return "smob"; /* should not occur. */ |
| 800 | break; |
| 801 | } |
| 802 | |
| 803 | return NULL; |
| 804 | } |
| 805 | |
| 806 | |
| 807 | |
| 808 | \f |
| 809 | void |
| 810 | scm_init_gc () |
| 811 | { |
| 812 | /* `GC_INIT ()' was invoked in `scm_storage_prehistory ()'. */ |
| 813 | |
| 814 | scm_after_gc_hook = scm_make_hook (SCM_INUM0); |
| 815 | scm_c_define ("after-gc-hook", scm_after_gc_hook); |
| 816 | |
| 817 | gc_async = scm_c_make_gsubr ("%gc-thunk", 0, 0, 0, gc_async_thunk); |
| 818 | |
| 819 | scm_c_hook_add (&scm_after_gc_c_hook, mark_gc_async, NULL, 0); |
| 820 | |
| 821 | #include "libguile/gc.x" |
| 822 | } |
| 823 | |
| 824 | |
| 825 | void |
| 826 | scm_gc_sweep (void) |
| 827 | #define FUNC_NAME "scm_gc_sweep" |
| 828 | { |
| 829 | /* FIXME */ |
| 830 | fprintf (stderr, "%s: doing nothing\n", FUNC_NAME); |
| 831 | } |
| 832 | #undef FUNC_NAME |
| 833 | |
| 834 | /* |
| 835 | Local Variables: |
| 836 | c-file-style: "gnu" |
| 837 | End: |
| 838 | */ |