#include "sgen/sgen-hash-table.h"
#include "sgen/sgen-qsort.h"
#include "utils/mono-logger-internals.h"
-
+#include "utils/mono-once.h"
+
+typedef enum {
+ BRIDGE_PROCESSOR_INVALID,
+ BRIDGE_PROCESSOR_OLD,
+ BRIDGE_PROCESSOR_NEW,
+ BRIDGE_PROCESSOR_TARJAN,
+ BRIDGE_PROCESSOR_DEFAULT = BRIDGE_PROCESSOR_TARJAN
+} BridgeProcessorSelection;
+
+// Bridge processor type pending / in use
+static BridgeProcessorSelection bridge_processor_selection = BRIDGE_PROCESSOR_DEFAULT;
+// Most recently requested callbacks
+static MonoGCBridgeCallbacks pending_bridge_callbacks;
+// Currently-in-use callbacks
MonoGCBridgeCallbacks bridge_callbacks;
+
+// Bridge processor state
static SgenBridgeProcessor bridge_processor;
+// This is used for a special debug feature
static SgenBridgeProcessor compare_to_bridge_processor;
volatile gboolean bridge_processing_in_progress = FALSE;
+// Mutex guarding pending_bridge_callbacks
+// Must use OS mutex because can be used before runtime init
+static mono_mutex_t pending_bridge_callbacks_mutex;
+
+static void
+pending_bridge_callbacks_mutex_init ()
+{
+ mono_os_mutex_init (&pending_bridge_callbacks_mutex);
+}
+
+static void
+pending_bridge_callbacks_mutex_lock ()
+{
+ static mono_once_t init_once=MONO_ONCE_INIT;
+ mono_once (&init_once, pending_bridge_callbacks_mutex_init);
+ mono_os_mutex_lock (&pending_bridge_callbacks_mutex);
+}
+
+static void
+pending_bridge_callbacks_mutex_unlock ()
+{
+ mono_os_mutex_unlock (&pending_bridge_callbacks_mutex);
+}
+
+// FIXME: The current usage pattern for this function is unsafe. Bridge processing could start immediately after unlock
void
mono_gc_wait_for_bridge_processing (void)
{
sgen_gc_unlock ();
}
+// This function is currently called only once, but it can be called at any time, including before or during sgen initialization.
void
mono_gc_register_bridge_callbacks (MonoGCBridgeCallbacks *callbacks)
{
if (callbacks->bridge_version != SGEN_BRIDGE_VERSION)
g_error ("Invalid bridge callback version. Expected %d but got %d\n", SGEN_BRIDGE_VERSION, callbacks->bridge_version);
- bridge_callbacks = *callbacks;
+ // Defer assigning to bridge_callbacks until we have the gc lock.
+ pending_bridge_callbacks_mutex_lock ();
+ pending_bridge_callbacks = *callbacks;
+ pending_bridge_callbacks_mutex_unlock ();
+
+ // If sgen has started, will assign bridge callbacks and init bridge
+ sgen_init_bridge ();
}
-static gboolean
-init_bridge_processor_by_name (SgenBridgeProcessor *processor, const char *name)
+static BridgeProcessorSelection
+bridge_processor_name (const char *name)
{
if (!strcmp ("old", name)) {
- memset (processor, 0, sizeof (SgenBridgeProcessor));
- sgen_old_bridge_init (processor);
+ return BRIDGE_PROCESSOR_OLD;
} else if (!strcmp ("new", name)) {
- memset (processor, 0, sizeof (SgenBridgeProcessor));
- sgen_new_bridge_init (processor);
+ return BRIDGE_PROCESSOR_NEW;
} else if (!strcmp ("tarjan", name)) {
- memset (processor, 0, sizeof (SgenBridgeProcessor));
- sgen_tarjan_bridge_init (processor);
+ return BRIDGE_PROCESSOR_TARJAN;
} else {
- return FALSE;
+ return BRIDGE_PROCESSOR_INVALID;
}
- return TRUE;
}
+// Initialize a single bridge processor
+static void
+init_bridge_processor (SgenBridgeProcessor *processor, BridgeProcessorSelection selection)
+{
+ memset (processor, 0, sizeof (SgenBridgeProcessor));
+
+ switch (selection) {
+ case BRIDGE_PROCESSOR_OLD:
+ sgen_old_bridge_init (processor);
+ break;
+ case BRIDGE_PROCESSOR_NEW:
+ sgen_new_bridge_init (processor);
+ break;
+ case BRIDGE_PROCESSOR_TARJAN:
+ sgen_tarjan_bridge_init (processor);
+ break;
+ default:
+ g_assert_not_reached ();
+ }
+}
+
+/*
+ * Initializing the sgen bridge consists of setting the bridge callbacks,
+ * and initializing the bridge processor. Init should follow these rules:
+ *
+ * - Init happens only after sgen is initialized (because we don't
+ * know which bridge processor to initialize until then, and also
+ * to allow bridge processor init to interact with sgen if it wants)
+ *
+ * - Init happens only after mono_gc_register_bridge_callbacks is called
+ *
+ * - Init should not happen concurrently with a GC (because a GC will
+ * call sgen_need_bridge_processing at various times)
+ *
+ * - Initializing the bridge processor should happen only once
+ *
+ * We call sgen_init_bridge when the callbacks are set, and also when sgen
+ * is done initing. Actual initialization then only occurs if it is ready.
+ */
void
-sgen_init_bridge_processor()
+sgen_init_bridge ()
{
- // If a bridge was registered but there is no bridge processor yet, init defaults
- if (bridge_callbacks.cross_references && !bridge_processor.reset_data)
- sgen_tarjan_bridge_init (&bridge_processor);
+ if (sgen_gc_initialized ()) {
+ // This lock is not initialized until the GC is
+ sgen_gc_lock ();
+
+ pending_bridge_callbacks_mutex_lock ();
+ bridge_callbacks = pending_bridge_callbacks;
+ pending_bridge_callbacks_mutex_unlock ();
+
+ // If a bridge was registered but there is no bridge processor yet
+ if (bridge_callbacks.cross_references && !bridge_processor.reset_data)
+ init_bridge_processor (&bridge_processor, bridge_processor_selection);
+
+ sgen_gc_unlock ();
+ }
}
void
sgen_set_bridge_implementation (const char *name)
{
- if (!init_bridge_processor_by_name (&bridge_processor, name))
- g_warning ("Invalid value for bridge implementation, valid values are: 'new', 'old' and 'tarjan'.");
+ BridgeProcessorSelection selection = bridge_processor_name (name);
+
+ if (selection == BRIDGE_PROCESSOR_INVALID)
+ g_warning ("Invalid value for bridge processor implementation, valid values are: 'new', 'old' and 'tarjan'.");
+ else if (bridge_processor.reset_data)
+ g_warning ("Cannot set bridge processor implementation once bridge has already started");
+ else
+ bridge_processor_selection = selection;
}
gboolean
set_dump_prefix (prefix);
} else if (g_str_has_prefix (opt, "bridge-compare-to=")) {
const char *name = strchr (opt, '=') + 1;
- if (init_bridge_processor_by_name (&compare_to_bridge_processor, name)) {
- if (compare_to_bridge_processor.reset_data == bridge_processor.reset_data) {
- g_warning ("Cannot compare bridge implementation to itself - ignoring.");
- memset (&compare_to_bridge_processor, 0, sizeof (SgenBridgeProcessor));
- }
+ BridgeProcessorSelection selection = bridge_processor_name (name);
+
+ if (selection != BRIDGE_PROCESSOR_INVALID) {
+ init_bridge_processor (&compare_to_bridge_processor, selection);
} else {
g_warning ("Invalid bridge implementation to compare against - ignoring.");
}
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