2 * sgen-bridge.c: Simple generational GC.
4 * Copyright 2011 Novell, Inc (http://www.novell.com)
5 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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13 * provided the above notices are retained, and a notice that the code was
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17 * Copyright 2001-2003 Ximian, Inc
18 * Copyright 2003-2010 Novell, Inc.
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47 #include "sgen-bridge.h"
48 #include "sgen-hash-table.h"
49 #include "sgen-qsort.h"
50 #include "utils/mono-logger-internal.h"
51 #include "utils/mono-time.h"
52 #include "utils/mono-compiler.h"
54 MonoGCBridgeCallbacks bridge_callbacks;
55 static SgenBridgeProcessor bridge_processor;
57 gboolean bridge_processing_in_progress = FALSE;
60 mono_gc_wait_for_bridge_processing (void)
62 if (!bridge_processing_in_progress)
65 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_BRIDGE waiting for bridge processing to finish");
73 mono_gc_register_bridge_callbacks (MonoGCBridgeCallbacks *callbacks)
75 if (callbacks->bridge_version != SGEN_BRIDGE_VERSION)
76 g_error ("Invalid bridge callback version. Expected %d but got %d\n", SGEN_BRIDGE_VERSION, callbacks->bridge_version);
78 bridge_callbacks = *callbacks;
80 if (!bridge_processor.reset_data)
81 sgen_old_bridge_init (&bridge_processor);
85 sgen_set_bridge_implementation (const char *name)
87 if (!strcmp ("old", name)) {
88 memset (&bridge_processor, 0, sizeof (SgenBridgeProcessor));
89 sgen_old_bridge_init (&bridge_processor);
90 } else if (!strcmp ("new", name)) {
91 memset (&bridge_processor, 0, sizeof (SgenBridgeProcessor));
92 sgen_new_bridge_init (&bridge_processor);
94 g_warning ("Invalid value for bridge implementation, valid values are: 'new' and 'old'.");
99 sgen_is_bridge_object (MonoObject *obj)
101 if ((obj->vtable->gc_bits & SGEN_GC_BIT_BRIDGE_OBJECT) != SGEN_GC_BIT_BRIDGE_OBJECT)
103 return bridge_callbacks.is_bridge_object (obj);
107 sgen_need_bridge_processing (void)
109 return bridge_callbacks.cross_references != NULL;
112 /* Dispatch wrappers */
114 sgen_bridge_reset_data (void)
116 bridge_processor.reset_data ();
120 sgen_bridge_processing_stw_step (void)
123 * bridge_processing_in_progress must be set with the world
124 * stopped. If not there would be race conditions.
126 bridge_processing_in_progress = TRUE;
128 bridge_processor.processing_stw_step ();
132 is_bridge_object_alive (MonoObject *obj, void *data)
134 SgenHashTable *table = data;
135 unsigned char *value = sgen_hash_table_lookup (table, obj);
142 sgen_bridge_processing_finish (int generation)
144 int num_sccs, num_xrefs;
145 MonoGCBridgeSCC **api_sccs;
146 MonoGCBridgeXRef *api_xrefs;
148 SgenHashTable alive_hash = SGEN_HASH_TABLE_INIT (INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE, INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE_ENTRY, 1, mono_aligned_addr_hash, NULL);
149 unsigned long step_8;
150 SGEN_TV_DECLARE (atv);
151 SGEN_TV_DECLARE (btv);
153 bridge_processor.processing_build_callback_data (generation);
155 if (bridge_processor.num_sccs == 0) {
156 g_assert (bridge_processor.num_xrefs == 0);
160 num_sccs = bridge_processor.num_sccs;
161 num_xrefs = bridge_processor.num_xrefs;
162 api_sccs = bridge_processor.api_sccs;
163 api_xrefs = bridge_processor.api_xrefs;
165 bridge_callbacks.cross_references (bridge_processor.num_sccs, bridge_processor.api_sccs,
166 bridge_processor.num_xrefs, bridge_processor.api_xrefs);
168 /* Release for finalization those objects we no longer care. */
169 SGEN_TV_GETTIME (btv);
171 for (i = 0; i < num_sccs; ++i) {
172 unsigned char alive = api_sccs [i]->is_alive ? 1 : 0;
173 for (j = 0; j < api_sccs [i]->num_objs; ++j) {
174 /* Build hash table for nulling weak links. */
175 sgen_hash_table_replace (&alive_hash, api_sccs [i]->objs [j], &alive, NULL);
177 /* Release for finalization those objects we no longer care. */
178 if (!api_sccs [i]->is_alive)
179 sgen_mark_bridge_object (api_sccs [i]->objs [j]);
183 /* Null weak links to dead objects. */
184 sgen_null_links_with_predicate (GENERATION_NURSERY, is_bridge_object_alive, &alive_hash);
185 if (generation == GENERATION_OLD)
186 sgen_null_links_with_predicate (GENERATION_OLD, is_bridge_object_alive, &alive_hash);
188 sgen_hash_table_clean (&alive_hash);
190 /* free callback data */
192 for (i = 0; i < num_sccs; ++i) {
193 sgen_free_internal_dynamic (api_sccs [i],
194 sizeof (MonoGCBridgeSCC) + sizeof (MonoObject*) * api_sccs [i]->num_objs,
195 INTERNAL_MEM_BRIDGE_DATA);
197 sgen_free_internal_dynamic (api_sccs, sizeof (MonoGCBridgeSCC*) * num_sccs, INTERNAL_MEM_BRIDGE_DATA);
199 sgen_free_internal_dynamic (api_xrefs, sizeof (MonoGCBridgeXRef) * num_xrefs, INTERNAL_MEM_BRIDGE_DATA);
201 bridge_processor.num_sccs = 0;
202 bridge_processor.api_sccs = NULL;
203 bridge_processor.num_xrefs = 0;
204 bridge_processor.api_xrefs = NULL;
206 SGEN_TV_GETTIME (atv);
207 step_8 = SGEN_TV_ELAPSED (btv, atv);
210 bridge_processor.processing_after_callback (generation);
212 bridge_processing_in_progress = FALSE;
215 MonoGCBridgeObjectKind
216 sgen_bridge_class_kind (MonoClass *class)
218 return bridge_processor.class_kind (class);
222 sgen_bridge_register_finalized_object (MonoObject *obj)
224 bridge_processor.register_finalized_object (obj);
228 sgen_bridge_describe_pointer (MonoObject *obj)
230 bridge_processor.describe_pointer (obj);
234 set_dump_prefix (const char *prefix)
236 if (!bridge_processor.set_dump_prefix) {
237 fprintf (stderr, "Warning: Bridge implementation does not support dumping - ignoring.\n");
241 bridge_processor.set_dump_prefix (prefix);
244 /* Test support code */
245 static const char *bridge_class;
247 static MonoGCBridgeObjectKind
248 bridge_test_bridge_class_kind (MonoClass *class)
250 if (!strcmp (bridge_class, class->name))
251 return GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS;
252 return GC_BRIDGE_TRANSPARENT_CLASS;
256 bridge_test_is_bridge_object (MonoObject *object)
262 bridge_test_cross_reference (int num_sccs, MonoGCBridgeSCC **sccs, int num_xrefs, MonoGCBridgeXRef *xrefs)
265 for (i = 0; i < num_sccs; ++i) {
267 // g_print ("--- SCC %d\n", i);
268 for (j = 0; j < sccs [i]->num_objs; ++j) {
269 // g_print (" %s\n", sgen_safe_name (sccs [i]->objs [j]));
270 if (i & 1) /*retain half of the bridged objects */
271 sccs [i]->is_alive = TRUE;
274 for (i = 0; i < num_xrefs; ++i) {
275 g_assert (xrefs [i].src_scc_index >= 0 && xrefs [i].src_scc_index < num_sccs);
276 g_assert (xrefs [i].dst_scc_index >= 0 && xrefs [i].dst_scc_index < num_sccs);
277 // g_print ("%d -> %d\n", xrefs [i].src_scc_index, xrefs [i].dst_scc_index);
281 static MonoClassField *mono_bridge_test_field;
291 test_scc (MonoGCBridgeSCC *scc, int i)
293 int status = BRIDGE_DEAD;
294 mono_field_get_value (scc->objs [i], mono_bridge_test_field, &status);
299 mark_scc (MonoGCBridgeSCC *scc, int value)
302 for (i = 0; i < scc->num_objs; ++i) {
303 if (!test_scc (scc, i)) {
305 mono_field_set_value (scc->objs [i], mono_bridge_test_field, &status);
311 bridge_test_cross_reference2 (int num_sccs, MonoGCBridgeSCC **sccs, int num_xrefs, MonoGCBridgeXRef *xrefs)
316 if (!mono_bridge_test_field) {
317 mono_bridge_test_field = mono_class_get_field_from_name (mono_object_get_class (sccs[0]->objs [0]), "__test");
318 g_assert (mono_bridge_test_field);
321 /*We mark all objects in a scc with live objects as reachable by scc*/
322 for (i = 0; i < num_sccs; ++i) {
324 gboolean live = FALSE;
325 for (j = 0; j < sccs [i]->num_objs; ++j) {
326 if (test_scc (sccs [i], j)) {
333 for (j = 0; j < sccs [i]->num_objs; ++j) {
334 if (!test_scc (sccs [i], j)) {
335 int status = BRIDGE_SAME_SCC;
336 mono_field_set_value (sccs [i]->objs [j], mono_bridge_test_field, &status);
341 /*Now we mark the transitive closure of reachable objects from the xrefs*/
345 /* Mark all objects that are brought to life due to xrefs*/
346 for (i = 0; i < num_xrefs; ++i) {
347 MonoGCBridgeXRef ref = xrefs [i];
348 if (test_scc (sccs [ref.src_scc_index], 0) && !test_scc (sccs [ref.dst_scc_index], 0)) {
350 mark_scc (sccs [ref.dst_scc_index], BRIDGE_XREF);
355 /* keep everything in memory, all we want to do is test persistence */
356 for (i = 0; i < num_sccs; ++i)
357 sccs [i]->is_alive = TRUE;
361 register_test_bridge_callbacks (const char *bridge_class_name)
363 MonoGCBridgeCallbacks callbacks;
364 callbacks.bridge_version = SGEN_BRIDGE_VERSION;
365 callbacks.bridge_class_kind = bridge_test_bridge_class_kind;
366 callbacks.is_bridge_object = bridge_test_is_bridge_object;
367 callbacks.cross_references = bridge_class_name[0] == '2' ? bridge_test_cross_reference2 : bridge_test_cross_reference;
368 mono_gc_register_bridge_callbacks (&callbacks);
369 bridge_class = bridge_class_name + (bridge_class_name[0] == '2' ? 1 : 0);
373 sgen_bridge_handle_gc_debug (const char *opt)
375 if (g_str_has_prefix (opt, "bridge=")) {
376 opt = strchr (opt, '=') + 1;
377 register_test_bridge_callbacks (g_strdup (opt));
378 } else if (!strcmp (opt, "enable-bridge-accounting")) {
379 bridge_processor.enable_accounting ();
380 } else if (g_str_has_prefix (opt, "bridge-dump=")) {
381 char *prefix = strchr (opt, '=') + 1;
382 set_dump_prefix (prefix);
390 sgen_bridge_print_gc_debug_usage (void)
392 fprintf (stderr, " bridge=<class-name>\n");
393 fprintf (stderr, " enable-bridge-accounting\n");
394 fprintf (stderr, " bridge-dump=<filename-prefix>\n");