jsgc.c

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        break;
      }

      case GCX_STRING:
      case GCX_MUTABLE_STRING: {
        JSString *str = (JSString *)thing;
        if (JSSTRING_IS_DEPENDENT(str)) {
            JS_snprintf(depbuf, sizeof depbuf, "start:%u, length:%u",
                        JSSTRDEP_START(str), JSSTRDEP_LENGTH(str));
            className = depbuf;
        } else {
            className = "string";
        }
        break;
      }

      case GCX_DOUBLE:
        className = "double";
        break;
    }

    return className;
}

static void
gc_dump_thing(JSGCThing *thing, uint8 flags, GCMarkNode *prev, FILE *fp)
{
    GCMarkNode *next = NULL;
    char *path = NULL;

    while (prev) {
        next = prev;
        prev = prev->prev;
    }
    while (next) {
        path = JS_sprintf_append(path, "%s(%s).",
                                 next->name,
                                 gc_object_class_name(next->thing));
        next = next->next;
    }
    if (!path)
        return;

    fprintf(fp, "%08lx ", (long)thing);
    switch (flags & GCF_TYPEMASK) {
      case GCX_OBJECT:
      {
        JSObject  *obj = (JSObject *)thing;
        jsval     privateValue = obj->slots[JSSLOT_PRIVATE];
        void      *privateThing = JSVAL_IS_VOID(privateValue)
                                  ? NULL
                                  : JSVAL_TO_PRIVATE(privateValue);
        const char *className = gc_object_class_name(thing);
        fprintf(fp, "object %8p %s", privateThing, className);
        break;
      }
      case GCX_DOUBLE:
        fprintf(fp, "double %g", *(jsdouble *)thing);
        break;
      default:
        fprintf(fp, "string %s", JS_GetStringBytes((JSString *)thing));
        break;
    }
    fprintf(fp, " via %s\n", path);
    free(path);
}

#endif /* !GC_MARK_DEBUG */

static void
gc_mark_atom_key_thing(void *thing, void *arg)
{
    JSContext *cx = (JSContext *) arg;

    GC_MARK(cx, thing, "atom", NULL);
}

void
js_MarkAtom(JSContext *cx, JSAtom *atom, void *arg)
{
    jsval key;

    if (atom->flags & ATOM_MARK)
        return;
    atom->flags |= ATOM_MARK;
    key = ATOM_KEY(atom);
    if (JSVAL_IS_GCTHING(key)) {
#ifdef GC_MARK_DEBUG
        char name[32];

        if (JSVAL_IS_STRING(key)) {
            JS_snprintf(name, sizeof name, "'%s'",
                        JS_GetStringBytes(JSVAL_TO_STRING(key)));
        } else {
            JS_snprintf(name, sizeof name, "<%x>", key);
        }
#endif
        GC_MARK(cx, JSVAL_TO_GCTHING(key), name, arg);
    }
}

void
js_MarkGCThing(JSContext *cx, void *thing, void *arg)
{
    uint8 flags, *flagp;
    JSRuntime *rt;
    JSObject *obj;
    uint32 nslots;
    jsval v, *vp, *end;
    JSString *str;
#ifdef GC_MARK_DEBUG
    JSScope *scope;
    JSScopeProperty *sprop;
#endif

    if (!thing)
        return;

    flagp = js_GetGCThingFlags(thing);
    flags = *flagp;
    JS_ASSERT(flags != GCF_FINAL);
#ifdef GC_MARK_DEBUG
    if (js_LiveThingToFind == thing)
        gc_dump_thing(thing, flags, arg, stderr);
#endif

    if (flags & GCF_MARK)
        return;

    *flagp |= GCF_MARK;
    rt = cx->runtime;
    METER(if (++rt->gcStats.depth > rt->gcStats.maxdepth)
              rt->gcStats.maxdepth = rt->gcStats.depth);

#ifdef GC_MARK_DEBUG
    if (!js_DumpGCHeap)
      js_DumpGCHeap = stderr;
    gc_dump_thing(thing, flags, arg, js_DumpGCHeap);
#endif

    switch (flags & GCF_TYPEMASK) {
      case GCX_OBJECT:
        obj = (JSObject *) thing;
        vp = obj->slots;
        if (!vp) {
            /* If obj->slots is null, obj must be a newborn. */
            JS_ASSERT(!obj->map);
            goto out;
        }
        nslots = (obj->map->ops->mark)
                 ? obj->map->ops->mark(cx, obj, arg)
                 : JS_MIN(obj->map->freeslot, obj->map->nslots);
#ifdef GC_MARK_DEBUG
        scope = OBJ_IS_NATIVE(obj) ? OBJ_SCOPE(obj) : NULL;
#endif
        for (end = vp + nslots; vp < end; vp++) {
            v = *vp;
            if (JSVAL_IS_GCTHING(v)) {
#ifdef GC_MARK_DEBUG
                char name[32];

                if (scope) {
                    uint32 slot;
                    jsval nval;

                    slot = vp - obj->slots;
                    for (sprop = SCOPE_LAST_PROP(scope); ;
                         sprop = sprop->parent) {
                        if (!sprop) {
                            switch (slot) {
                              case JSSLOT_PROTO:
                                strcpy(name, "__proto__");
                                break;
                              case JSSLOT_PARENT:
                                strcpy(name, "__parent__");
                                break;
                              case JSSLOT_PRIVATE:
                                strcpy(name, "__private__");
                                break;
                              default:
                                JS_snprintf(name, sizeof name,
                                            "**UNKNOWN SLOT %ld**",
                                            (long)slot);
                                break;
                            }
                            break;
                        }
                        if (sprop->slot == slot) {
                            nval = ID_TO_VALUE(sprop->id);
                            if (JSVAL_IS_INT(nval)) {
                                JS_snprintf(name, sizeof name, "%ld",
                                            (long)JSVAL_TO_INT(nval));
                            } else if (JSVAL_IS_STRING(nval)) {
                                JS_snprintf(name, sizeof name, "%s",
                                  JS_GetStringBytes(JSVAL_TO_STRING(nval)));
                            } else {
                                strcpy(name, "**FINALIZED ATOM KEY**");
                            }
                            break;
                        }
                    }
                } else {
                    strcpy(name, "**UNKNOWN OBJECT MAP ENTRY**");
                }
#endif
                GC_MARK(cx, JSVAL_TO_GCTHING(v), name, arg);
            }
        }
        break;

#ifdef DEBUG
      case GCX_STRING:
        str = (JSString *)thing;
        JS_ASSERT(!JSSTRING_IS_DEPENDENT(str));
        break;
#endif

      case GCX_MUTABLE_STRING:
        str = (JSString *)thing;
        if (JSSTRING_IS_DEPENDENT(str))
            GC_MARK(cx, JSSTRDEP_BASE(str), "base", arg);
        break;
    }

out:
    METER(rt->gcStats.depth--);
}

JS_STATIC_DLL_CALLBACK(JSDHashOperator)
gc_root_marker(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32 num, void *arg)
{
    JSGCRootHashEntry *rhe = (JSGCRootHashEntry *)hdr;
    jsval *rp = (jsval *)rhe->root;
    jsval v = *rp;

    /* Ignore null object and scalar values. */
    if (!JSVAL_IS_NULL(v) && JSVAL_IS_GCTHING(v)) {
        JSContext *cx = (JSContext *)arg;
#ifdef DEBUG
        JSArena *a;
        jsuword firstpage;
        JSBool root_points_to_gcArenaPool = JS_FALSE;
        void *thing = JSVAL_TO_GCTHING(v);

        for (a = cx->runtime->gcArenaPool.first.next; a; a = a->next) {
            firstpage = FIRST_THING_PAGE(a);
            if (JS_UPTRDIFF(thing, firstpage) < a->avail - firstpage) {
                root_points_to_gcArenaPool = JS_TRUE;
                break;
            }
        }
        if (!root_points_to_gcArenaPool && rhe->name) {
            fprintf(stderr,
"JS API usage error: the address passed to JS_AddNamedRoot currently holds an\n"
"invalid jsval.  This is usually caused by a missing call to JS_RemoveRoot.\n"
"The root's name is \"%s\".\n",
                    rhe->name);
        }
        JS_ASSERT(root_points_to_gcArenaPool);
#endif

        GC_MARK(cx, JSVAL_TO_GCTHING(v), rhe->name ? rhe->name : "root", NULL);
    }
    return JS_DHASH_NEXT;
}

JS_STATIC_DLL_CALLBACK(JSDHashOperator)
gc_lock_marker(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32 num, void *arg)
{
    JSGCLockHashEntry *lhe = (JSGCLockHashEntry *)hdr;
    void *thing = (void *)lhe->thing;
    JSContext *cx = (JSContext *)arg;

    GC_MARK(cx, thing, "locked object", NULL);
    return JS_DHASH_NEXT;
}

void
js_ForceGC(JSContext *cx, uintN gcflags)
{
    uintN i;

    for (i = 0; i < GCX_NTYPES; i++)
        cx->newborn[i] = NULL;
    cx->lastAtom = NULL;
    cx->runtime->gcPoke = JS_TRUE;
    js_GC(cx, gcflags);
    JS_ArenaFinish();
}

#define GC_MARK_JSVALS(cx, len, vec, name)                                    \
    JS_BEGIN_MACRO                                                            \
        jsval _v, *_vp, *_end;                                                \
                                                                              \
        for (_vp = vec, _end = _vp + len; _vp < _end; _vp++) {                \
            _v = *_vp;                                                        \
            if (JSVAL_IS_GCTHING(_v))                                         \
                GC_MARK(cx, JSVAL_TO_GCTHING(_v), name, NULL);                \
        }                                                                     \
    JS_END_MACRO

void
js_GC(JSContext *cx, uintN gcflags)
{
    JSRuntime *rt;
    JSContext *iter, *acx;
    JSStackFrame *fp, *chain;
    uintN i, depth, nslots, type;
    JSStackHeader *sh;
    JSArena *a, **ap;
    uint8 flags, *flagp, *split;
    JSGCThing *thing, *limit, **flp, **oflp;
    GCFinalizeOp finalizer;
    JSBool all_clear;
#ifdef JS_THREADSAFE
    jsword currentThread;
    uint32 requestDebit;
#endif

    rt = cx->runtime;
#ifdef JS_THREADSAFE
    /* Avoid deadlock. */
    JS_ASSERT(!JS_IS_RUNTIME_LOCKED(rt));
#endif

    /*
     * Don't collect garbage if the runtime isn't up, and cx is not the last
     * context in the runtime.  The last context must force a GC, and nothing
     * should suppress that final collection or there may be shutdown leaks,
     * or runtime bloat until the next context is created.
     */
    if (rt->state != JSRTS_UP && !(gcflags & GC_LAST_CONTEXT))
        return;

    /*
     * Let the API user decide to defer a GC if it wants to (unless this
     * is the last context).  Invoke the callback regardless.
     */
    if (rt->gcCallback) {
        if (!rt->gcCallback(cx, JSGC_BEGIN) && !(gcflags & GC_LAST_CONTEXT))
            return;
    }

    /* Lock out other GC allocator and collector invocations. */
    if (!(gcflags & GC_ALREADY_LOCKED))
        JS_LOCK_GC(rt);

    /* Do nothing if no assignment has executed since the last GC. */
    if (!rt->gcPoke) {
        METER(rt->gcStats.nopoke++);
        if (!(gcflags & GC_ALREADY_LOCKED))
            JS_UNLOCK_GC(rt);
        return;
    }
    METER(rt->gcStats.poke++);

#ifdef JS_THREADSAFE