2 * sgen-toggleref.c: toggleref support for sgen
5 * Rodrigo Kumpera (kumpera@gmail.com)
7 * Copyright 2011 Xamarin, Inc.
8 * Copyright (C) 2012 Xamarin Inc
10 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
17 #include "sgen/sgen-gc.h"
18 #include "sgen-toggleref.h"
19 #include "sgen/sgen-client.h"
22 /*only one of the two can be non null at a given time*/
28 static MonoToggleRefStatus (*toggleref_callback
) (MonoObject
*obj
);
29 static MonoGCToggleRef
*toggleref_array
;
30 static int toggleref_array_size
;
31 static int toggleref_array_capacity
;
34 sgen_process_togglerefs (void)
37 int toggle_ref_counts
[3] = { 0, 0, 0 };
39 SGEN_LOG (4, "Proccessing ToggleRefs %d", toggleref_array_size
);
41 for (i
= w
= 0; i
< toggleref_array_size
; ++i
) {
43 MonoGCToggleRef r
= toggleref_array
[i
];
54 res
= toggleref_callback (obj
);
55 ++toggle_ref_counts
[res
];
57 case MONO_TOGGLE_REF_DROP
:
59 case MONO_TOGGLE_REF_STRONG
:
60 toggleref_array
[w
].strong_ref
= obj
;
61 toggleref_array
[w
].weak_ref
= NULL
;
64 case MONO_TOGGLE_REF_WEAK
:
65 toggleref_array
[w
].strong_ref
= NULL
;
66 toggleref_array
[w
].weak_ref
= obj
;
70 g_assert_not_reached ();
74 toggleref_array_size
= w
;
76 SGEN_LOG (4, "Done Proccessing ToggleRefs dropped %d strong %d weak %d final size %d",
77 toggle_ref_counts
[MONO_TOGGLE_REF_DROP
],
78 toggle_ref_counts
[MONO_TOGGLE_REF_STRONG
],
79 toggle_ref_counts
[MONO_TOGGLE_REF_WEAK
],
83 void sgen_client_mark_togglerefs (char *start
, char *end
, ScanCopyContext ctx
)
85 CopyOrMarkObjectFunc copy_func
= ctx
.ops
->copy_or_mark_object
;
86 SgenGrayQueue
*queue
= ctx
.queue
;
89 SGEN_LOG (4, "Marking ToggleRefs %d", toggleref_array_size
);
91 for (i
= 0; i
< toggleref_array_size
; ++i
) {
92 if (toggleref_array
[i
].strong_ref
) {
93 GCObject
*object
= toggleref_array
[i
].strong_ref
;
94 if ((char*)object
>= start
&& (char*)object
< end
) {
95 SGEN_LOG (6, "\tcopying strong slot %d", i
);
96 copy_func (&toggleref_array
[i
].strong_ref
, queue
);
100 sgen_drain_gray_stack (ctx
);
103 void sgen_client_clear_togglerefs (char *start
, char *end
, ScanCopyContext ctx
)
105 CopyOrMarkObjectFunc copy_func
= ctx
.ops
->copy_or_mark_object
;
106 SgenGrayQueue
*queue
= ctx
.queue
;
109 SGEN_LOG (4, "Clearing ToggleRefs %d", toggleref_array_size
);
111 for (i
= 0; i
< toggleref_array_size
; ++i
) {
112 if (toggleref_array
[i
].weak_ref
) {
113 GCObject
*object
= toggleref_array
[i
].weak_ref
;
115 if ((char*)object
>= start
&& (char*)object
< end
) {
116 if (sgen_gc_is_object_ready_for_finalization (object
)) {
117 SGEN_LOG (6, "\tcleaning weak slot %d", i
);
118 toggleref_array
[i
].weak_ref
= NULL
; /* We defer compaction to only happen on the callback step. */
120 SGEN_LOG (6, "\tkeeping weak slot %d", i
);
121 copy_func (&toggleref_array
[i
].weak_ref
, queue
);
126 sgen_drain_gray_stack (ctx
);
130 ensure_toggleref_capacity (int capacity
)
132 if (!toggleref_array
) {
133 toggleref_array_capacity
= 32;
134 toggleref_array
= (MonoGCToggleRef
*)sgen_alloc_internal_dynamic (
135 toggleref_array_capacity
* sizeof (MonoGCToggleRef
),
136 INTERNAL_MEM_TOGGLEREF_DATA
,
139 if (toggleref_array_size
+ capacity
>= toggleref_array_capacity
) {
140 MonoGCToggleRef
*tmp
;
141 int old_capacity
= toggleref_array_capacity
;
142 while (toggleref_array_capacity
< toggleref_array_size
+ capacity
)
143 toggleref_array_capacity
*= 2;
145 tmp
= (MonoGCToggleRef
*)sgen_alloc_internal_dynamic (
146 toggleref_array_capacity
* sizeof (MonoGCToggleRef
),
147 INTERNAL_MEM_TOGGLEREF_DATA
,
150 memcpy (tmp
, toggleref_array
, toggleref_array_size
* sizeof (MonoGCToggleRef
));
152 sgen_free_internal_dynamic (toggleref_array
, old_capacity
* sizeof (MonoGCToggleRef
), INTERNAL_MEM_TOGGLEREF_DATA
);
153 toggleref_array
= tmp
;
158 * mono_gc_toggleref_add:
159 * @object object to register for toggleref processing
160 * @strong_ref if true the object is registered with a strong ref, a weak one otherwise
162 * Register a given object for toggleref processing. It will be stored internally and the toggleref callback will be called
163 * on it until it returns MONO_TOGGLE_REF_DROP or is collected.
166 mono_gc_toggleref_add (MonoObject
*object
, mono_bool strong_ref
)
168 if (!toggleref_callback
)
171 SGEN_LOG (4, "Adding toggleref %p %d", object
, strong_ref
);
175 ensure_toggleref_capacity (1);
176 toggleref_array
[toggleref_array_size
].strong_ref
= strong_ref
? object
: NULL
;
177 toggleref_array
[toggleref_array_size
].weak_ref
= strong_ref
? NULL
: object
;
178 ++toggleref_array_size
;
184 * mono_gc_toggleref_register_callback:
185 * @callback callback used to determine the new state of the given object.
187 * The callback must decide the status of a given object. It must return one of the values in the MONO_TOGGLE_REF_ enum.
188 * This function is called with the world running but with the GC locked. This means that you can do everything that doesn't
189 * require GC interaction. This includes, but not limited to, allocating objects, (de)registering for finalization, manipulating
190 *gchandles, storing to reference fields or interacting with other threads that might perform such operations.
193 mono_gc_toggleref_register_callback (MonoToggleRefStatus (*proccess_toggleref
) (MonoObject
*obj
))
195 toggleref_callback
= proccess_toggleref
;
198 static MonoToggleRefStatus
199 test_toggleref_callback (MonoObject
*obj
)
201 static MonoClassField
*mono_toggleref_test_field
;
202 MonoToggleRefStatus status
= MONO_TOGGLE_REF_DROP
;
204 if (!mono_toggleref_test_field
) {
205 mono_toggleref_test_field
= mono_class_get_field_from_name (mono_object_get_class (obj
), "__test");
206 g_assert (mono_toggleref_test_field
);
209 mono_field_get_value (obj
, mono_toggleref_test_field
, &status
);
210 printf ("toggleref-cb obj %d\n", status
);
215 sgen_register_test_toggleref_callback (void)
217 toggleref_callback
= test_toggleref_callback
;