1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
20 * file for a list of people on the GLib Team. See the ChangeLog
21 * files for a list of changes. These files are distributed with
22 * GLib at ftp://ftp.gtk.org/pub/gtk/.
38 #include "gbacktrace.h"
39 #include "gtestutils.h"
41 #include "glib_trace.h"
43 #define MEM_PROFILE_TABLE_SIZE 4096
47 * having G_DISABLE_CHECKS defined disables use of glib_mem_profiler_table and
49 * If g_mem_gc_friendly is TRUE, freed memory should be 0-wiped.
52 /* --- variables --- */
53 static GMemVTable glib_mem_vtable
= {
64 * @Short_Description: general memory-handling
65 * @Title: Memory Allocation
67 * These functions provide support for allocating and freeing memory.
69 * If any call to allocate memory fails, the application is terminated.
70 * This also means that there is no need to check if the call succeeded.
72 * It's important to match g_malloc() (and wrappers such as g_new()) with
73 * g_free(), g_slice_alloc() and wrappers such as g_slice_new()) with
74 * g_slice_free(), plain malloc() with free(), and (if you're using C++)
75 * new with delete and new[] with delete[]. Otherwise bad things can happen,
76 * since these allocators may use different memory pools (and new/delete call
77 * constructors and destructors). See also g_mem_set_vtable().
80 /* --- functions --- */
83 * @n_bytes: the number of bytes to allocate
85 * Allocates @n_bytes bytes of memory.
86 * If @n_bytes is 0 it returns %NULL.
88 * Returns: a pointer to the allocated memory
91 g_malloc (gsize n_bytes
)
93 if (G_LIKELY (n_bytes
))
97 mem
= glib_mem_vtable
.malloc (n_bytes
);
98 TRACE (GLIB_MEM_ALLOC((void*) mem
, (unsigned int) n_bytes
, 0, 0));
102 g_error ("%s: failed to allocate %"G_GSIZE_FORMAT
" bytes",
106 TRACE(GLIB_MEM_ALLOC((void*) NULL
, (int) n_bytes
, 0, 0));
113 * @n_bytes: the number of bytes to allocate
115 * Allocates @n_bytes bytes of memory, initialized to 0's.
116 * If @n_bytes is 0 it returns %NULL.
118 * Returns: a pointer to the allocated memory
121 g_malloc0 (gsize n_bytes
)
123 if (G_LIKELY (n_bytes
))
127 mem
= glib_mem_vtable
.calloc (1, n_bytes
);
128 TRACE (GLIB_MEM_ALLOC((void*) mem
, (unsigned int) n_bytes
, 1, 0));
132 g_error ("%s: failed to allocate %"G_GSIZE_FORMAT
" bytes",
136 TRACE(GLIB_MEM_ALLOC((void*) NULL
, (int) n_bytes
, 1, 0));
143 * @mem: (allow-none): the memory to reallocate
144 * @n_bytes: new size of the memory in bytes
146 * Reallocates the memory pointed to by @mem, so that it now has space for
147 * @n_bytes bytes of memory. It returns the new address of the memory, which may
148 * have been moved. @mem may be %NULL, in which case it's considered to
149 * have zero-length. @n_bytes may be 0, in which case %NULL will be returned
150 * and @mem will be freed unless it is %NULL.
152 * Returns: the new address of the allocated memory
155 g_realloc (gpointer mem
,
160 if (G_LIKELY (n_bytes
))
162 newmem
= glib_mem_vtable
.realloc (mem
, n_bytes
);
163 TRACE (GLIB_MEM_REALLOC((void*) newmem
, (void*)mem
, (unsigned int) n_bytes
, 0));
167 g_error ("%s: failed to allocate %"G_GSIZE_FORMAT
" bytes",
172 glib_mem_vtable
.free (mem
);
174 TRACE (GLIB_MEM_REALLOC((void*) NULL
, (void*)mem
, 0, 0));
181 * @mem: (allow-none): the memory to free
183 * Frees the memory pointed to by @mem.
184 * If @mem is %NULL it simply returns.
187 g_free (gpointer mem
)
190 glib_mem_vtable
.free (mem
);
191 TRACE(GLIB_MEM_FREE((void*) mem
));
195 * g_clear_pointer: (skip)
196 * @pp: a pointer to a variable, struct member etc. holding a pointer
197 * @destroy: a function to which a gpointer can be passed, to destroy *@pp
199 * Clears a reference to a variable.
201 * @pp must not be %NULL.
203 * If the reference is %NULL then this function does nothing.
204 * Otherwise, the variable is destroyed using @destroy and the
205 * pointer is set to %NULL.
207 * This function is threadsafe and modifies the pointer atomically,
208 * using memory barriers where needed.
210 * A macro is also included that allows this function to be used without
215 #undef g_clear_pointer
217 g_clear_pointer (gpointer
*pp
,
218 GDestroyNotify destroy
)
222 /* This is a little frustrating.
223 * Would be nice to have an atomic exchange (with no compare).
226 _p
= g_atomic_pointer_get (pp
);
227 while G_UNLIKELY (!g_atomic_pointer_compare_and_exchange (pp
, _p
, NULL
));
235 * @n_bytes: number of bytes to allocate.
237 * Attempts to allocate @n_bytes, and returns %NULL on failure.
238 * Contrast with g_malloc(), which aborts the program on failure.
240 * Returns: the allocated memory, or %NULL.
243 g_try_malloc (gsize n_bytes
)
247 if (G_LIKELY (n_bytes
))
248 mem
= glib_mem_vtable
.try_malloc (n_bytes
);
252 TRACE (GLIB_MEM_ALLOC((void*) mem
, (unsigned int) n_bytes
, 0, 1));
259 * @n_bytes: number of bytes to allocate
261 * Attempts to allocate @n_bytes, initialized to 0's, and returns %NULL on
262 * failure. Contrast with g_malloc0(), which aborts the program on failure.
265 * Returns: the allocated memory, or %NULL
268 g_try_malloc0 (gsize n_bytes
)
272 if (G_LIKELY (n_bytes
))
273 mem
= glib_mem_vtable
.try_malloc (n_bytes
);
278 memset (mem
, 0, n_bytes
);
285 * @mem: (allow-none): previously-allocated memory, or %NULL.
286 * @n_bytes: number of bytes to allocate.
288 * Attempts to realloc @mem to a new size, @n_bytes, and returns %NULL
289 * on failure. Contrast with g_realloc(), which aborts the program
290 * on failure. If @mem is %NULL, behaves the same as g_try_malloc().
292 * Returns: the allocated memory, or %NULL.
295 g_try_realloc (gpointer mem
,
300 if (G_LIKELY (n_bytes
))
301 newmem
= glib_mem_vtable
.try_realloc (mem
, n_bytes
);
306 glib_mem_vtable
.free (mem
);
309 TRACE (GLIB_MEM_REALLOC((void*) newmem
, (void*)mem
, (unsigned int) n_bytes
, 1));
315 #define SIZE_OVERFLOWS(a,b) (G_UNLIKELY ((b) > 0 && (a) > G_MAXSIZE / (b)))
319 * @n_blocks: the number of blocks to allocate
320 * @n_block_bytes: the size of each block in bytes
322 * This function is similar to g_malloc(), allocating (@n_blocks * @n_block_bytes) bytes,
323 * but care is taken to detect possible overflow during multiplication.
326 * Returns: a pointer to the allocated memory
329 g_malloc_n (gsize n_blocks
,
332 if (SIZE_OVERFLOWS (n_blocks
, n_block_bytes
))
334 g_error ("%s: overflow allocating %"G_GSIZE_FORMAT
"*%"G_GSIZE_FORMAT
" bytes",
335 G_STRLOC
, n_blocks
, n_block_bytes
);
338 return g_malloc (n_blocks
* n_block_bytes
);
343 * @n_blocks: the number of blocks to allocate
344 * @n_block_bytes: the size of each block in bytes
346 * This function is similar to g_malloc0(), allocating (@n_blocks * @n_block_bytes) bytes,
347 * but care is taken to detect possible overflow during multiplication.
350 * Returns: a pointer to the allocated memory
353 g_malloc0_n (gsize n_blocks
,
356 if (SIZE_OVERFLOWS (n_blocks
, n_block_bytes
))
358 g_error ("%s: overflow allocating %"G_GSIZE_FORMAT
"*%"G_GSIZE_FORMAT
" bytes",
359 G_STRLOC
, n_blocks
, n_block_bytes
);
362 return g_malloc0 (n_blocks
* n_block_bytes
);
367 * @mem: (allow-none): the memory to reallocate
368 * @n_blocks: the number of blocks to allocate
369 * @n_block_bytes: the size of each block in bytes
371 * This function is similar to g_realloc(), allocating (@n_blocks * @n_block_bytes) bytes,
372 * but care is taken to detect possible overflow during multiplication.
375 * Returns: the new address of the allocated memory
378 g_realloc_n (gpointer mem
,
382 if (SIZE_OVERFLOWS (n_blocks
, n_block_bytes
))
384 g_error ("%s: overflow allocating %"G_GSIZE_FORMAT
"*%"G_GSIZE_FORMAT
" bytes",
385 G_STRLOC
, n_blocks
, n_block_bytes
);
388 return g_realloc (mem
, n_blocks
* n_block_bytes
);
393 * @n_blocks: the number of blocks to allocate
394 * @n_block_bytes: the size of each block in bytes
396 * This function is similar to g_try_malloc(), allocating (@n_blocks * @n_block_bytes) bytes,
397 * but care is taken to detect possible overflow during multiplication.
400 * Returns: the allocated memory, or %NULL.
403 g_try_malloc_n (gsize n_blocks
,
406 if (SIZE_OVERFLOWS (n_blocks
, n_block_bytes
))
409 return g_try_malloc (n_blocks
* n_block_bytes
);
414 * @n_blocks: the number of blocks to allocate
415 * @n_block_bytes: the size of each block in bytes
417 * This function is similar to g_try_malloc0(), allocating (@n_blocks * @n_block_bytes) bytes,
418 * but care is taken to detect possible overflow during multiplication.
421 * Returns: the allocated memory, or %NULL
424 g_try_malloc0_n (gsize n_blocks
,
427 if (SIZE_OVERFLOWS (n_blocks
, n_block_bytes
))
430 return g_try_malloc0 (n_blocks
* n_block_bytes
);
435 * @mem: (allow-none): previously-allocated memory, or %NULL.
436 * @n_blocks: the number of blocks to allocate
437 * @n_block_bytes: the size of each block in bytes
439 * This function is similar to g_try_realloc(), allocating (@n_blocks * @n_block_bytes) bytes,
440 * but care is taken to detect possible overflow during multiplication.
443 * Returns: the allocated memory, or %NULL.
446 g_try_realloc_n (gpointer mem
,
450 if (SIZE_OVERFLOWS (n_blocks
, n_block_bytes
))
453 return g_try_realloc (mem
, n_blocks
* n_block_bytes
);
459 fallback_calloc (gsize n_blocks
,
462 gsize l
= n_blocks
* n_block_bytes
;
463 gpointer mem
= glib_mem_vtable
.malloc (l
);
471 static gboolean vtable_set
= FALSE
;
474 * g_mem_is_system_malloc:
476 * Checks whether the allocator used by g_malloc() is the system's
477 * malloc implementation. If it returns %TRUE memory allocated with
478 * malloc() can be used interchangeable with memory allocated using g_malloc().
479 * This function is useful for avoiding an extra copy of allocated memory returned
480 * by a non-GLib-based API.
482 * A different allocator can be set using g_mem_set_vtable().
484 * Returns: if %TRUE, malloc() and g_malloc() can be mixed.
487 g_mem_is_system_malloc (void)
494 * @vtable: table of memory allocation routines.
496 * Sets the #GMemVTable to use for memory allocation. You can use this
497 * to provide custom memory allocation routines.
499 * The @vtable only needs to provide malloc(), realloc(), and free()
500 * functions; GLib can provide default implementations of the others.
501 * The malloc() and realloc() implementations should return %NULL on
502 * failure, GLib will handle error-checking for you. @vtable is copied,
503 * so need not persist after this function has been called.
505 * Note that this function must be called before using any other GLib
509 g_mem_set_vtable (GMemVTable
*vtable
)
513 if (vtable
->malloc
&& vtable
->realloc
&& vtable
->free
)
515 glib_mem_vtable
.malloc
= vtable
->malloc
;
516 glib_mem_vtable
.realloc
= vtable
->realloc
;
517 glib_mem_vtable
.free
= vtable
->free
;
518 glib_mem_vtable
.calloc
= vtable
->calloc
? vtable
->calloc
: fallback_calloc
;
519 glib_mem_vtable
.try_malloc
= vtable
->try_malloc
? vtable
->try_malloc
: glib_mem_vtable
.malloc
;
520 glib_mem_vtable
.try_realloc
= vtable
->try_realloc
? vtable
->try_realloc
: glib_mem_vtable
.realloc
;
524 g_warning (G_STRLOC
": memory allocation vtable lacks one of malloc(), realloc() or free()");
527 g_warning (G_STRLOC
": memory allocation vtable can only be set once at startup");
531 /* --- memory profiling and checking --- */
532 #ifdef G_DISABLE_CHECKS
534 * glib_mem_profiler_table:
536 * A #GMemVTable containing profiling variants of the memory
537 * allocation functions. Use them together with g_mem_profile()
538 * in order to get information about the memory allocation pattern
541 GMemVTable
*glib_mem_profiler_table
= &glib_mem_vtable
;
546 #else /* !G_DISABLE_CHECKS */
553 static guint
*profile_data
= NULL
;
554 static gsize profile_allocs
= 0;
555 static gsize profile_zinit
= 0;
556 static gsize profile_frees
= 0;
557 static GMutex gmem_profile_mutex
;
559 #define PROFILE_TABLE(f1,f2,f3) ( ( ((f3) << 2) | ((f2) << 1) | (f1) ) * (MEM_PROFILE_TABLE_SIZE + 1))
562 profiler_log (ProfilerJob job
,
566 g_mutex_lock (&gmem_profile_mutex
);
569 profile_data
= calloc ((MEM_PROFILE_TABLE_SIZE
+ 1) * 8,
570 sizeof (profile_data
[0]));
571 if (!profile_data
) /* memory system kiddin' me, eh? */
573 g_mutex_unlock (&gmem_profile_mutex
);
578 if (n_bytes
< MEM_PROFILE_TABLE_SIZE
)
579 profile_data
[n_bytes
+ PROFILE_TABLE ((job
& PROFILER_ALLOC
) != 0,
580 (job
& PROFILER_RELOC
) != 0,
583 profile_data
[MEM_PROFILE_TABLE_SIZE
+ PROFILE_TABLE ((job
& PROFILER_ALLOC
) != 0,
584 (job
& PROFILER_RELOC
) != 0,
588 if (job
& PROFILER_ALLOC
)
590 profile_allocs
+= n_bytes
;
591 if (job
& PROFILER_ZINIT
)
592 profile_zinit
+= n_bytes
;
595 profile_frees
+= n_bytes
;
597 g_mutex_unlock (&gmem_profile_mutex
);
601 profile_print_locked (guint
*local_data
,
604 gboolean need_header
= TRUE
;
607 for (i
= 0; i
<= MEM_PROFILE_TABLE_SIZE
; i
++)
609 glong t_malloc
= local_data
[i
+ PROFILE_TABLE (1, 0, success
)];
610 glong t_realloc
= local_data
[i
+ PROFILE_TABLE (1, 1, success
)];
611 glong t_free
= local_data
[i
+ PROFILE_TABLE (0, 0, success
)];
612 glong t_refree
= local_data
[i
+ PROFILE_TABLE (0, 1, success
)];
614 if (!t_malloc
&& !t_realloc
&& !t_free
&& !t_refree
)
616 else if (need_header
)
619 g_print (" blocks of | allocated | freed | allocated | freed | n_bytes \n");
620 g_print (" n_bytes | n_times by | n_times by | n_times by | n_times by | remaining \n");
621 g_print (" | malloc() | free() | realloc() | realloc() | \n");
622 g_print ("===========|============|============|============|============|===========\n");
624 if (i
< MEM_PROFILE_TABLE_SIZE
)
625 g_print ("%10u | %10ld | %10ld | %10ld | %10ld |%+11ld\n",
626 i
, t_malloc
, t_free
, t_realloc
, t_refree
,
627 (t_malloc
- t_free
+ t_realloc
- t_refree
) * i
);
628 else if (i
>= MEM_PROFILE_TABLE_SIZE
)
629 g_print (" >%6u | %10ld | %10ld | %10ld | %10ld | ***\n",
630 i
, t_malloc
, t_free
, t_realloc
, t_refree
);
633 g_print (" --- none ---\n");
639 * Outputs a summary of memory usage.
641 * It outputs the frequency of allocations of different sizes,
642 * the total number of bytes which have been allocated,
643 * the total number of bytes which have been freed,
644 * and the difference between the previous two values, i.e. the number of bytes
647 * Note that this function will not output anything unless you have
648 * previously installed the #glib_mem_profiler_table with g_mem_set_vtable().
654 guint local_data
[(MEM_PROFILE_TABLE_SIZE
+ 1) * 8];
659 g_mutex_lock (&gmem_profile_mutex
);
661 local_allocs
= profile_allocs
;
662 local_zinit
= profile_zinit
;
663 local_frees
= profile_frees
;
667 g_mutex_unlock (&gmem_profile_mutex
);
671 memcpy (local_data
, profile_data
,
672 (MEM_PROFILE_TABLE_SIZE
+ 1) * 8 * sizeof (profile_data
[0]));
674 g_mutex_unlock (&gmem_profile_mutex
);
676 g_print ("GLib Memory statistics (successful operations):\n");
677 profile_print_locked (local_data
, TRUE
);
678 g_print ("GLib Memory statistics (failing operations):\n");
679 profile_print_locked (local_data
, FALSE
);
680 g_print ("Total bytes: allocated=%"G_GSIZE_FORMAT
", "
681 "zero-initialized=%"G_GSIZE_FORMAT
" (%.2f%%), "
682 "freed=%"G_GSIZE_FORMAT
" (%.2f%%), "
683 "remaining=%"G_GSIZE_FORMAT
"\n",
686 ((gdouble
) local_zinit
) / local_allocs
* 100.0,
688 ((gdouble
) local_frees
) / local_allocs
* 100.0,
689 local_allocs
- local_frees
);
693 profiler_try_malloc (gsize n_bytes
)
697 p
= malloc (sizeof (gsize
) * 2 + n_bytes
);
701 p
[0] = 0; /* free count */
702 p
[1] = n_bytes
; /* length */
703 profiler_log (PROFILER_ALLOC
, n_bytes
, TRUE
);
707 profiler_log (PROFILER_ALLOC
, n_bytes
, FALSE
);
713 profiler_malloc (gsize n_bytes
)
715 gpointer mem
= profiler_try_malloc (n_bytes
);
724 profiler_calloc (gsize n_blocks
,
727 gsize l
= n_blocks
* n_block_bytes
;
730 p
= calloc (1, sizeof (gsize
) * 2 + l
);
734 p
[0] = 0; /* free count */
735 p
[1] = l
; /* length */
736 profiler_log (PROFILER_ALLOC
| PROFILER_ZINIT
, l
, TRUE
);
741 profiler_log (PROFILER_ALLOC
| PROFILER_ZINIT
, l
, FALSE
);
749 profiler_free (gpointer mem
)
754 if (p
[0]) /* free count */
756 g_warning ("free(%p): memory has been freed %"G_GSIZE_FORMAT
" times already",
758 profiler_log (PROFILER_FREE
,
764 profiler_log (PROFILER_FREE
,
767 memset (p
+ 2, 0xaa, p
[1]);
769 /* for all those that miss free (p); in this place, yes,
770 * we do leak all memory when profiling, and that is intentional
771 * to catch double frees. patch submissions are futile.
778 profiler_try_realloc (gpointer mem
,
785 if (mem
&& p
[0]) /* free count */
787 g_warning ("realloc(%p, %"G_GSIZE_FORMAT
"): "
788 "memory has been freed %"G_GSIZE_FORMAT
" times already",
789 p
+ 2, (gsize
) n_bytes
, p
[0]);
790 profiler_log (PROFILER_ALLOC
| PROFILER_RELOC
, n_bytes
, FALSE
);
796 p
= realloc (mem
? p
: NULL
, sizeof (gsize
) * 2 + n_bytes
);
801 profiler_log (PROFILER_FREE
| PROFILER_RELOC
, p
[1], TRUE
);
804 profiler_log (PROFILER_ALLOC
| PROFILER_RELOC
, p
[1], TRUE
);
808 profiler_log (PROFILER_ALLOC
| PROFILER_RELOC
, n_bytes
, FALSE
);
815 profiler_realloc (gpointer mem
,
818 mem
= profiler_try_realloc (mem
, n_bytes
);
826 static GMemVTable profiler_table
= {
832 profiler_try_realloc
,
834 GMemVTable
*glib_mem_profiler_table
= &profiler_table
;
836 #endif /* !G_DISABLE_CHECKS */