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1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 *
3 * ***** BEGIN LICENSE BLOCK *****
4 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
5 *
6 * The contents of this file are subject to the Mozilla Public License Version
7 * 1.1 (the "License"); you may not use this file except in compliance with
8 * the License. You may obtain a copy of the License at
9 * http://www.mozilla.org/MPL/
10 *
11 * Software distributed under the License is distributed on an "AS IS" basis,
12 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13 * for the specific language governing rights and limitations under the
14 * License.
15 *
16 * The Original Code is Mozilla Communicator client code, released
17 * March 31, 1998.
18 *
19 * The Initial Developer of the Original Code is
20 * Netscape Communications Corporation.
21 * Portions created by the Initial Developer are Copyright (C) 1998
22 * the Initial Developer. All Rights Reserved.
23 *
24 * Contributor(s):
25 *
26 * Alternatively, the contents of this file may be used under the terms of
27 * either of the GNU General Public License Version 2 or later (the "GPL"),
28 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
29 * in which case the provisions of the GPL or the LGPL are applicable instead
30 * of those above. If you wish to allow use of your version of this file only
31 * under the terms of either the GPL or the LGPL, and not to allow others to
32 * use your version of this file under the terms of the MPL, indicate your
33 * decision by deleting the provisions above and replace them with the notice
34 * and other provisions required by the GPL or the LGPL. If you do not delete
35 * the provisions above, a recipient may use your version of this file under
36 * the terms of any one of the MPL, the GPL or the LGPL.
37 *
38 * ***** END LICENSE BLOCK ***** */
39
40 #ifndef jsgc_h___
41 #define jsgc_h___
42 /*
43 * JS Garbage Collector.
44 */
45 #include "jsprvtd.h"
46 #include "jspubtd.h"
47 #include "jsdhash.h"
48
49 JS_BEGIN_EXTERN_C
50
51 /* GC thing type indexes. */
52 #define GCX_OBJECT 0 /* JSObject */
53 #define GCX_STRING 1 /* JSString */
54 #define GCX_DOUBLE 2 /* jsdouble */
55 #define GCX_MUTABLE_STRING 3 /* JSString that's mutable --
56 single-threaded only! */
57 #define GCX_PRIVATE 4 /* private (unscanned) data */
58 #define GCX_NAMESPACE 5 /* JSXMLNamespace */
59 #define GCX_QNAME 6 /* JSXMLQName */
60 #define GCX_XML 7 /* JSXML */
61 #define GCX_EXTERNAL_STRING 8 /* JSString w/ external chars */
62
63 #define GCX_NTYPES_LOG2 4 /* type index bits */
64 #define GCX_NTYPES JS_BIT(GCX_NTYPES_LOG2)
65
66 /* GC flag definitions, must fit in 8 bits (type index goes in the low bits). */
67 #define GCF_TYPEMASK JS_BITMASK(GCX_NTYPES_LOG2)
68 #define GCF_MARK JS_BIT(GCX_NTYPES_LOG2)
69 #define GCF_FINAL JS_BIT(GCX_NTYPES_LOG2 + 1)
70 #define GCF_SYSTEM JS_BIT(GCX_NTYPES_LOG2 + 2)
71 #define GCF_LOCKSHIFT (GCX_NTYPES_LOG2 + 3) /* lock bit shift */
72 #define GCF_LOCK JS_BIT(GCF_LOCKSHIFT) /* lock request bit in API */
73
74 /* Pseudo-flag that modifies GCX_STRING to make GCX_MUTABLE_STRING. */
75 #define GCF_MUTABLE 2
76
77 #if (GCX_STRING | GCF_MUTABLE) != GCX_MUTABLE_STRING
78 # error "mutable string type index botch!"
79 #endif
80
81 extern uint8 *
82 js_GetGCThingFlags(void *thing);
83
84 /* These are compatible with JSDHashEntryStub. */
85 struct JSGCRootHashEntry {
86 JSDHashEntryHdr hdr;
87 void *root;
88 const char *name;
89 };
90
91 struct JSGCLockHashEntry {
92 JSDHashEntryHdr hdr;
93 const JSGCThing *thing;
94 uint32 count;
95 };
96
97 #if 1
98 /*
99 * Since we're forcing a GC from JS_GC anyway, don't bother wasting cycles
100 * loading oldval. XXX remove implied force, fix jsinterp.c's "second arg
101 * ignored", etc.
102 */
103 #define GC_POKE(cx, oldval) ((cx)->runtime->gcPoke = JS_TRUE)
104 #else
105 #define GC_POKE(cx, oldval) ((cx)->runtime->gcPoke = JSVAL_IS_GCTHING(oldval))
106 #endif
107
108 extern intN
109 js_ChangeExternalStringFinalizer(JSStringFinalizeOp oldop,
110 JSStringFinalizeOp newop);
111
112 extern JSBool
113 js_InitGC(JSRuntime *rt, uint32 maxbytes);
114
115 extern void
116 js_FinishGC(JSRuntime *rt);
117
118 extern JSBool
119 js_AddRoot(JSContext *cx, void *rp, const char *name);
120
121 extern JSBool
122 js_AddRootRT(JSRuntime *rt, void *rp, const char *name);
123
124 extern JSBool
125 js_RemoveRoot(JSRuntime *rt, void *rp);
126
127 /*
128 * The private JSGCThing struct, which describes a gcFreeList element.
129 */
130 struct JSGCThing {
131 JSGCThing *next;
132 uint8 *flagp;
133 };
134
135 #define GC_NBYTES_MAX (10 * sizeof(JSGCThing))
136 #define GC_NUM_FREELISTS (GC_NBYTES_MAX / sizeof(JSGCThing))
137 #define GC_FREELIST_NBYTES(i) (((i) + 1) * sizeof(JSGCThing))
138 #define GC_FREELIST_INDEX(n) (((n) / sizeof(JSGCThing)) - 1)
139
140 extern void *
141 js_NewGCThing(JSContext *cx, uintN flags, size_t nbytes);
142
143 extern JSBool
144 js_LockGCThing(JSContext *cx, void *thing);
145
146 extern JSBool
147 js_LockGCThingRT(JSRuntime *rt, void *thing);
148
149 extern JSBool
150 js_UnlockGCThingRT(JSRuntime *rt, void *thing);
151
152 extern JSBool
153 js_IsAboutToBeFinalized(JSContext *cx, void *thing);
154
155 extern void
156 js_MarkAtom(JSContext *cx, JSAtom *atom, void *arg);
157
158 /* We avoid a large number of unnecessary calls by doing the flag check first */
159 #define GC_MARK_ATOM(cx, atom, arg) \
160 JS_BEGIN_MACRO \
161 if (!((atom)->flags & ATOM_MARK)) \
162 js_MarkAtom(cx, atom, arg); \
163 JS_END_MACRO
164
165 extern void
166 js_MarkGCThing(JSContext *cx, void *thing, void *arg);
167
168 #ifdef GC_MARK_DEBUG
169
170 typedef struct GCMarkNode GCMarkNode;
171
172 struct GCMarkNode {
173 void *thing;
174 const char *name;
175 GCMarkNode *next;
176 GCMarkNode *prev;
177 };
178
179 #define GC_MARK(cx_, thing_, name_, prev_) \
180 JS_BEGIN_MACRO \
181 GCMarkNode node_; \
182 node_.thing = thing_; \
183 node_.name = name_; \
184 node_.next = NULL; \
185 node_.prev = prev_; \
186 if (prev_) ((GCMarkNode *)(prev_))->next = &node_; \
187 js_MarkGCThing(cx_, thing_, &node_); \
188 JS_END_MACRO
189
190 #else /* !GC_MARK_DEBUG */
191
192 #define GC_MARK(cx, thing, name, prev) js_MarkGCThing(cx, thing, NULL)
193
194 #endif /* !GC_MARK_DEBUG */
195
196 /*
197 * Flags to modify how a GC marks and sweeps:
198 * GC_KEEP_ATOMS Don't sweep unmarked atoms, they may be in use by the
199 * compiler, or by an API function that calls js_Atomize,
200 * when the GC is called from js_NewGCThing, due to a
201 * malloc failure or the runtime GC-thing limit.
202 * GC_LAST_CONTEXT Called from js_DestroyContext for last JSContext in a
203 * JSRuntime, when it is imperative that rt->gcPoke gets
204 * cleared early in js_GC, if it is set.
205 * GC_ALREADY_LOCKED rt->gcLock is already held on entry to js_GC, and kept
206 * on return to its caller.
207 */
208 #define GC_KEEP_ATOMS 0x1
209 #define GC_LAST_CONTEXT 0x2
210 #define GC_ALREADY_LOCKED 0x4
211
212 extern void
213 js_ForceGC(JSContext *cx, uintN gcflags);
214
215 extern void
216 js_GC(JSContext *cx, uintN gcflags);
217
218 #ifdef DEBUG_notme
219 #define JS_GCMETER 1
220 #endif
221
222 #ifdef JS_GCMETER
223
224 typedef struct JSGCStats {
225 uint32 alloc; /* number of allocation attempts */
226 uint32 freelen[GC_NUM_FREELISTS];
227 /* gcFreeList lengths */
228 uint32 recycle[GC_NUM_FREELISTS];
229 /* number of things recycled through gcFreeList */
230 uint32 retry; /* allocation attempt retries after running the GC */
231 uint32 retryhalt; /* allocation retries halted by the branch callback */
232 uint32 fail; /* allocation failures */
233 uint32 finalfail; /* finalizer calls allocator failures */
234 uint32 lockborn; /* things born locked */
235 uint32 lock; /* valid lock calls */
236 uint32 unlock; /* valid unlock calls */
237 uint32 depth; /* mark tail recursion depth */
238 uint32 maxdepth; /* maximum mark tail recursion depth */
239 uint32 cdepth; /* mark recursion depth of C functions */
240 uint32 maxcdepth; /* maximum mark recursion depth of C functions */
241 uint32 dswmark; /* mark C stack overflows => Deutsch-Schorr-Waite */
242 uint32 dswdepth; /* DSW mark depth */
243 uint32 maxdswdepth;/* maximum DSW mark depth */
244 uint32 dswup; /* DSW moves up the mark spanning tree */
245 uint32 dswupstep; /* steps in obj->slots to find DSW-reversed pointer */
246 uint32 maxlevel; /* maximum GC nesting (indirect recursion) level */
247 uint32 poke; /* number of potentially useful GC calls */
248 uint32 nopoke; /* useless GC calls where js_PokeGC was not set */
249 uint32 afree; /* thing arenas freed so far */
250 uint32 stackseg; /* total extraordinary stack segments scanned */
251 uint32 segslots; /* total stack segment jsval slots scanned */
252 } JSGCStats;
253
254 extern JS_FRIEND_API(void)
255 js_DumpGCStats(JSRuntime *rt, FILE *fp);
256
257 #endif /* JS_GCMETER */
258
259 #ifdef DEBUG_notme
260 #define TOO_MUCH_GC 1
261 #endif
262
263 #ifdef WAY_TOO_MUCH_GC
264 #define TOO_MUCH_GC 1
265 #endif
266
267 JS_END_EXTERN_C
268
269 #endif /* jsgc_h___ */
270
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