jsscript.c

来自「java script test programing source code」· C语言 代码 · 共 1,718 行 · 第 1/4 页

    sfe->mark = JS_TRUE;
    return HT_ENUMERATE_NEXT;
}

void
js_MarkScriptFilenames(JSRuntime *rt, JSBool keepAtoms)
{
    JSCList *head, *link;
    ScriptFilenamePrefix *sfp;

    if (!rt->scriptFilenameTable)
        return;

    if (keepAtoms) {
        JS_HashTableEnumerateEntries(rt->scriptFilenameTable,
                                     js_script_filename_marker,
                                     rt);
    }
    for (head = &rt->scriptFilenamePrefixes, link = head->next;
         link != head;
         link = link->next) {
        sfp = (ScriptFilenamePrefix *) link;
        js_MarkScriptFilename(sfp->name);
    }
}

JS_STATIC_DLL_CALLBACK(intN)
js_script_filename_sweeper(JSHashEntry *he, intN i, void *arg)
{
    ScriptFilenameEntry *sfe = (ScriptFilenameEntry *) he;

    if (!sfe->mark)
        return HT_ENUMERATE_REMOVE;
    sfe->mark = JS_FALSE;
    return HT_ENUMERATE_NEXT;
}

void
js_SweepScriptFilenames(JSRuntime *rt)
{
    if (!rt->scriptFilenameTable)
        return;

    JS_HashTableEnumerateEntries(rt->scriptFilenameTable,
                                 js_script_filename_sweeper,
                                 rt);
#ifdef DEBUG_notme
#ifdef DEBUG_SFTBL
    printf("script filename table savings so far: %u\n", sftbl_savings);
#endif
#endif
}

JSScript *
js_NewScript(JSContext *cx, uint32 length, uint32 nsrcnotes, uint32 ntrynotes)
{
    JSScript *script;

    /* Round up source note count to align script->trynotes for its type. */
    if (ntrynotes)
        nsrcnotes += JSTRYNOTE_ALIGNMASK;
    script = (JSScript *) JS_malloc(cx,
                                    sizeof(JSScript) +
                                    length * sizeof(jsbytecode) +
                                    nsrcnotes * sizeof(jssrcnote) +
                                    ntrynotes * sizeof(JSTryNote));
    if (!script)
        return NULL;
    memset(script, 0, sizeof(JSScript));
    script->code = script->main = (jsbytecode *)(script + 1);
    script->length = length;
    script->version = cx->version;
    if (ntrynotes) {
        script->trynotes = (JSTryNote *)
                           ((jsword)(SCRIPT_NOTES(script) + nsrcnotes) &
                            ~(jsword)JSTRYNOTE_ALIGNMASK);
        memset(script->trynotes, 0, ntrynotes * sizeof(JSTryNote));
    }
    return script;
}

JS_FRIEND_API(JSScript *)
js_NewScriptFromCG(JSContext *cx, JSCodeGenerator *cg, JSFunction *fun)
{
    uint32 mainLength, prologLength, nsrcnotes, ntrynotes;
    JSScript *script;
    const char *filename;

    mainLength = CG_OFFSET(cg);
    prologLength = CG_PROLOG_OFFSET(cg);
    CG_COUNT_FINAL_SRCNOTES(cg, nsrcnotes);
    CG_COUNT_FINAL_TRYNOTES(cg, ntrynotes);
    script = js_NewScript(cx, prologLength + mainLength, nsrcnotes, ntrynotes);
    if (!script)
        return NULL;

    /* Now that we have script, error control flow must go to label bad. */
    script->main += prologLength;
    memcpy(script->code, CG_PROLOG_BASE(cg), prologLength * sizeof(jsbytecode));
    memcpy(script->main, CG_BASE(cg), mainLength * sizeof(jsbytecode));
    script->numGlobalVars = cg->treeContext.numGlobalVars;
    if (!js_InitAtomMap(cx, &script->atomMap, &cg->atomList))
        goto bad;

    filename = cg->filename;
    if (filename) {
        script->filename = js_SaveScriptFilename(cx, filename);
        if (!script->filename)
            goto bad;
    }
    script->lineno = cg->firstLine;
    script->depth = cg->maxStackDepth;
    if (cg->principals) {
        script->principals = cg->principals;
        JSPRINCIPALS_HOLD(cx, script->principals);
    }

    if (!js_FinishTakingSrcNotes(cx, cg, SCRIPT_NOTES(script)))
        goto bad;
    if (script->trynotes)
        js_FinishTakingTryNotes(cx, cg, script->trynotes);

    /*
     * We initialize fun->u.script to be the script constructed above
     * so that the debugger has a valid FUN_SCRIPT(fun).
     */
    if (fun) {
        JS_ASSERT(FUN_INTERPRETED(fun) && !FUN_SCRIPT(fun));
        fun->u.i.script = script;
        if (cg->treeContext.flags & TCF_FUN_HEAVYWEIGHT)
            fun->flags |= JSFUN_HEAVYWEIGHT;
    }

    /* Tell the debugger about this compiled script. */
    js_CallNewScriptHook(cx, script, fun);
    return script;

bad:
    js_DestroyScript(cx, script);
    return NULL;
}

JS_FRIEND_API(void)
js_CallNewScriptHook(JSContext *cx, JSScript *script, JSFunction *fun)
{
    JSRuntime *rt;
    JSNewScriptHook hook;

    rt = cx->runtime;
    hook = rt->newScriptHook;
    if (hook) {
        JS_KEEP_ATOMS(rt);
        hook(cx, script->filename, script->lineno, script, fun,
             rt->newScriptHookData);
        JS_UNKEEP_ATOMS(rt);
    }
}

JS_FRIEND_API(void)
js_CallDestroyScriptHook(JSContext *cx, JSScript *script)
{
    JSRuntime *rt;
    JSDestroyScriptHook hook;

    rt = cx->runtime;
    hook = rt->destroyScriptHook;
    if (hook)
        hook(cx, script, rt->destroyScriptHookData);
}

void
js_DestroyScript(JSContext *cx, JSScript *script)
{
    js_CallDestroyScriptHook(cx, script);

    JS_ClearScriptTraps(cx, script);
    js_FreeAtomMap(cx, &script->atomMap);
    if (script->principals)
        JSPRINCIPALS_DROP(cx, script->principals);
    if (JS_GSN_CACHE(cx).script == script)
        JS_CLEAR_GSN_CACHE(cx);
    JS_free(cx, script);
}

void
js_MarkScript(JSContext *cx, JSScript *script)
{
    JSAtomMap *map;
    uintN i, length;
    JSAtom **vector;

    map = &script->atomMap;
    length = map->length;
    vector = map->vector;
    for (i = 0; i < length; i++)
        GC_MARK_ATOM(cx, vector[i]);

    if (script->filename)
        js_MarkScriptFilename(script->filename);
}

typedef struct GSNCacheEntry {
    JSDHashEntryHdr     hdr;
    jsbytecode          *pc;
    jssrcnote           *sn;
} GSNCacheEntry;

#define GSN_CACHE_THRESHOLD     100

jssrcnote *
js_GetSrcNoteCached(JSContext *cx, JSScript *script, jsbytecode *pc)
{
    ptrdiff_t target, offset;
    GSNCacheEntry *entry;
    jssrcnote *sn, *result;
    uintN nsrcnotes;


    target = PTRDIFF(pc, script->code, jsbytecode);
    if ((uint32)target >= script->length)
        return NULL;

    if (JS_GSN_CACHE(cx).script == script) {
        JS_METER_GSN_CACHE(cx, hits);
        entry = (GSNCacheEntry *)
                JS_DHashTableOperate(&JS_GSN_CACHE(cx).table, pc,
                                     JS_DHASH_LOOKUP);
        return entry->sn;
    }

    JS_METER_GSN_CACHE(cx, misses);
    offset = 0;
    for (sn = SCRIPT_NOTES(script); ; sn = SN_NEXT(sn)) {
        if (SN_IS_TERMINATOR(sn)) {
            result = NULL;
            break;
        }
        offset += SN_DELTA(sn);
        if (offset == target && SN_IS_GETTABLE(sn)) {
            result = sn;
            break;
        }
    }

    if (JS_GSN_CACHE(cx).script != script &&
        script->length >= GSN_CACHE_THRESHOLD) {
        JS_CLEAR_GSN_CACHE(cx);
        nsrcnotes = 0;
        for (sn = SCRIPT_NOTES(script); !SN_IS_TERMINATOR(sn);
             sn = SN_NEXT(sn)) {
            if (SN_IS_GETTABLE(sn))
                ++nsrcnotes;
        }
        if (!JS_DHashTableInit(&JS_GSN_CACHE(cx).table, JS_DHashGetStubOps(),
                               NULL, sizeof(GSNCacheEntry), nsrcnotes)) {
            JS_GSN_CACHE(cx).table.ops = NULL;
        } else {
            pc = script->code;
            for (sn = SCRIPT_NOTES(script); !SN_IS_TERMINATOR(sn);
                 sn = SN_NEXT(sn)) {
                pc += SN_DELTA(sn);
                if (SN_IS_GETTABLE(sn)) {
                    entry = (GSNCacheEntry *)
                            JS_DHashTableOperate(&JS_GSN_CACHE(cx).table, pc,
                                                 JS_DHASH_ADD);
                    entry->pc = pc;
                    entry->sn = sn;
                }
            }
            JS_GSN_CACHE(cx).script = script;
            JS_METER_GSN_CACHE(cx, fills);
        }
    }

    return result;
}

uintN
js_PCToLineNumber(JSContext *cx, JSScript *script, jsbytecode *pc)
{
    JSAtom *atom;
    JSFunction *fun;
    uintN lineno;
    ptrdiff_t offset, target;
    jssrcnote *sn;
    JSSrcNoteType type;

    /* Cope with JSStackFrame.pc value prior to entering js_Interpret. */
    if (!pc)
        return 0;

    /*
     * Special case: function definition needs no line number note because
     * the function's script contains its starting line number.
     */
    if (*pc == JSOP_DEFFUN ||
        (*pc == JSOP_LITOPX && pc[1 + LITERAL_INDEX_LEN] == JSOP_DEFFUN)) {
        atom = js_GetAtom(cx, &script->atomMap,
                          (*pc == JSOP_DEFFUN)
                          ? GET_ATOM_INDEX(pc)
                          : GET_LITERAL_INDEX(pc));
        fun = (JSFunction *) JS_GetPrivate(cx, ATOM_TO_OBJECT(atom));
        JS_ASSERT(FUN_INTERPRETED(fun));
        return fun->u.i.script->lineno;
    }

    /*
     * General case: walk through source notes accumulating their deltas,
     * keeping track of line-number notes, until we pass the note for pc's
     * offset within script->code.
     */
    lineno = script->lineno;
    offset = 0;
    target = PTRDIFF(pc, script->code, jsbytecode);
    for (sn = SCRIPT_NOTES(script); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
        offset += SN_DELTA(sn);
        type = (JSSrcNoteType) SN_TYPE(sn);
        if (type == SRC_SETLINE) {
            if (offset <= target)
                lineno = (uintN) js_GetSrcNoteOffset(sn, 0);
        } else if (type == SRC_NEWLINE) {
            if (offset <= target)
                lineno++;
        }
        if (offset > target)
            break;
    }
    return lineno;
}

/* The line number limit is the same as the jssrcnote offset limit. */
#define SN_LINE_LIMIT   (SN_3BYTE_OFFSET_FLAG << 16)

jsbytecode *
js_LineNumberToPC(JSScript *script, uintN target)
{
    ptrdiff_t offset, best;
    uintN lineno, bestdiff, diff;
    jssrcnote *sn;
    JSSrcNoteType type;

    offset = 0;
    best = -1;
    lineno = script->lineno;
    bestdiff = SN_LINE_LIMIT;
    for (sn = SCRIPT_NOTES(script); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
        if (lineno == target)
            goto out;
        if (lineno > target) {
            diff = lineno - target;
            if (diff < bestdiff) {
                bestdiff = diff;
                best = offset;
            }
        }
        offset += SN_DELTA(sn);
        type = (JSSrcNoteType) SN_TYPE(sn);
        if (type == SRC_SETLINE) {
            lineno = (uintN) js_GetSrcNoteOffset(sn, 0);
        } else if (type == SRC_NEWLINE) {
            lineno++;
        }
    }
    if (best >= 0)
        offset = best;
out:
    return script->code + offset;
}

JS_FRIEND_API(uintN)
js_GetScriptLineExtent(JSScript *script)
{
    uintN lineno;
    jssrcnote *sn;
    JSSrcNoteType type;

    lineno = script->lineno;
    for (sn = SCRIPT_NOTES(script); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
        type = (JSSrcNoteType) SN_TYPE(sn);
        if (type == SRC_SETLINE) {
            lineno = (uintN) js_GetSrcNoteOffset(sn, 0);
        } else if (type == SRC_NEWLINE) {
            lineno++;
        }
    }
    return 1 + lineno - script->lineno;
}

#if JS_HAS_GENERATORS

jsbytecode *
js_FindFinallyHandler(JSScript *script, jsbytecode *pc)
{
    JSTryNote *tn;
    ptrdiff_t off;
    JSOp op2;

    tn = script->trynotes;
    if (!tn)
        return NULL;

    off = pc - script->main;
    if (off < 0)
        return NULL;

    JS_ASSERT(tn->catchStart != 0);
    do {
        if ((jsuword)(off - tn->start) < (jsuword)tn->length) {
            /*
             * We have a handler: is it the finally one, or a catch handler?
             *
             * Catch bytecode begins with:   JSOP_SETSP JSOP_ENTERBLOCK
             * Finally bytecode begins with: JSOP_SETSP JSOP_(GOSUB|EXCEPTION)
             */
            pc = script->main + tn->catchStart;
            JS_ASSERT(*pc == JSOP_SETSP);
            op2 = pc[JSOP_SETSP_LENGTH];
            if (op2 != JSOP_ENTERBLOCK) {
                JS_ASSERT(op2 == JSOP_GOSUB || op2 == JSOP_EXCEPTION);
                return pc;
            }
        }
    } while ((++tn)->catchStart != 0);
    return NULL;
}

#endif