jsinterp.c

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/* build on macs with low memory */
#if defined(XP_MAC) && defined(MOZ_MAC_LOWMEM)
#pragma optimization_level 1
#endif

/*
 * JavaScript bytecode interpreter.
 */
#include "jsstddef.h"
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "jstypes.h"
#include "jsarena.h" /* Added by JSIFY */
#include "jsutil.h" /* Added by JSIFY */
#include "jsprf.h"
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jsbool.h"
#include "jscntxt.h"
#include "jsconfig.h"
#include "jsdbgapi.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsinterp.h"
#include "jslock.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstr.h"

#if JS_HAS_JIT
#include "jsjit.h"
#endif

#ifdef DEBUG
#define ASSERT_CACHE_IS_EMPTY(cache)                                          \
    JS_BEGIN_MACRO                                                            \
        JSPropertyCacheEntry *end_, *pce_, entry_;                            \
        JSPropertyCache *cache_ = (cache);                                    \
        JS_ASSERT(cache_->empty);                                             \
        end_ = &cache_->table[PROPERTY_CACHE_SIZE];                           \
        for (pce_ = &cache_->table[0]; pce_ < end_; pce_++) {                 \
            PCE_LOAD(cache_, pce_, entry_);                                   \
            JS_ASSERT(!PCE_OBJECT(entry_));                                   \
            JS_ASSERT(!PCE_PROPERTY(entry_));                                 \
        }                                                                     \
    JS_END_MACRO
#else
#define ASSERT_CACHE_IS_EMPTY(cache) ((void)0)
#endif

void
js_FlushPropertyCache(JSContext *cx)
{
    JSPropertyCache *cache;

    cache = &cx->runtime->propertyCache;
    if (cache->empty) {
        ASSERT_CACHE_IS_EMPTY(cache);
        return;
    }
    memset(cache->table, 0, sizeof cache->table);
    cache->empty = JS_TRUE;
#ifdef JS_PROPERTY_CACHE_METERING
    cache->flushes++;
#endif
}

void
js_DisablePropertyCache(JSContext *cx)
{
    JS_ASSERT(!cx->runtime->propertyCache.disabled);
    cx->runtime->propertyCache.disabled = JS_TRUE;
}

void
js_EnablePropertyCache(JSContext *cx)
{
    JS_ASSERT(cx->runtime->propertyCache.disabled);
    ASSERT_CACHE_IS_EMPTY(&cx->runtime->propertyCache);
    cx->runtime->propertyCache.disabled = JS_FALSE;
}

/*
 * Class for for/in loop property iterator objects.
 */
#define JSSLOT_ITER_STATE   JSSLOT_PRIVATE

static void
prop_iterator_finalize(JSContext *cx, JSObject *obj)
{
    jsval iter_state;
    jsval iteratee;

    /* Protect against stillborn iterators. */
    iter_state = obj->slots[JSSLOT_ITER_STATE];
    iteratee = obj->slots[JSSLOT_PARENT];
    if (!JSVAL_IS_NULL(iter_state) && !JSVAL_IS_PRIMITIVE(iteratee)) {
        OBJ_ENUMERATE(cx, JSVAL_TO_OBJECT(iteratee), JSENUMERATE_DESTROY,
                      &iter_state, NULL);
    }
    js_RemoveRoot(cx->runtime, &obj->slots[JSSLOT_PARENT]);

    /* XXX force the GC to restart so we can collect iteratee, if possible,
           during the current collector activation */
    cx->runtime->gcLevel++;
}

static JSClass prop_iterator_class = {
    "PropertyIterator",
    0,
    JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,
    JS_EnumerateStub, JS_ResolveStub,   JS_ConvertStub,   prop_iterator_finalize,
    JSCLASS_NO_OPTIONAL_MEMBERS
};

/*
 * Stack macros and functions.  These all use a local variable, jsval *sp, to
 * point to the next free stack slot.  SAVE_SP must be called before any call
 * to a function that may invoke the interpreter.  RESTORE_SP must be called
 * only after return from js_Invoke, because only js_Invoke changes fp->sp.
 */
#define PUSH(v)         (*sp++ = (v))
#define POP()           (*--sp)
#ifdef DEBUG
#define SAVE_SP(fp)                                                           \
    (JS_ASSERT((fp)->script || !(fp)->spbase || (sp) == (fp)->spbase),        \
     (fp)->sp = sp)
#else
#define SAVE_SP(fp)     ((fp)->sp = sp)
#endif
#define RESTORE_SP(fp)  (sp = (fp)->sp)

/*
 * Push the generating bytecode's pc onto the parallel pc stack that runs
 * depth slots below the operands.
 *
 * NB: PUSH_OPND uses sp, depth, and pc from its lexical environment.  See
 * js_Interpret for these local variables' declarations and uses.
 */
#define PUSH_OPND(v)    (sp[-depth] = (jsval)pc, PUSH(v))
#define STORE_OPND(n,v) (sp[(n)-depth] = (jsval)pc, sp[n] = (v))
#define POP_OPND()      POP()
#define FETCH_OPND(n)   (sp[n])

/*
 * Push the jsdouble d using sp, depth, and pc from the lexical environment.
 * Try to convert d to a jsint that fits in a jsval, otherwise GC-alloc space
 * for it and push a reference.
 */
#define STORE_NUMBER(cx, n, d)                                                \
    JS_BEGIN_MACRO                                                            \
        jsint i_;                                                             \
        jsval v_;                                                             \
                                                                              \
        if (JSDOUBLE_IS_INT(d, i_) && INT_FITS_IN_JSVAL(i_)) {                \
            v_ = INT_TO_JSVAL(i_);                                            \
        } else {                                                              \
            ok = js_NewDoubleValue(cx, d, &v_);                               \
            if (!ok)                                                          \
                goto out;                                                     \
        }                                                                     \
        STORE_OPND(n, v_);                                                    \
    JS_END_MACRO

#define FETCH_NUMBER(cx, n, d)                                                \
    JS_BEGIN_MACRO                                                            \
        jsval v_;                                                             \
                                                                              \
        v_ = FETCH_OPND(n);                                                   \
        VALUE_TO_NUMBER(cx, v_, d);                                           \
    JS_END_MACRO

#define FETCH_INT(cx, n, i)                                                   \
    JS_BEGIN_MACRO                                                            \
        jsval v_ = FETCH_OPND(n);                                             \
        if (JSVAL_IS_INT(v_)) {                                               \
            i = JSVAL_TO_INT(v_);                                             \
        } else {                                                              \
            SAVE_SP(fp);                                                      \
            ok = js_ValueToECMAInt32(cx, v_, &i);                             \
            if (!ok)                                                          \
                goto out;                                                     \
        }                                                                     \
    JS_END_MACRO

#define FETCH_UINT(cx, n, ui)                                                 \
    JS_BEGIN_MACRO                                                            \
        jsval v_ = FETCH_OPND(n);                                             \
        jsint i_;                                                             \
        if (JSVAL_IS_INT(v_) && (i_ = JSVAL_TO_INT(v_)) >= 0) {               \
            ui = (uint32) i_;                                                 \
        } else {                                                              \
            SAVE_SP(fp);                                                      \
            ok = js_ValueToECMAUint32(cx, v_, &ui);                           \
            if (!ok)                                                          \
                goto out;                                                     \
        }                                                                     \
    JS_END_MACRO

/*
 * Optimized conversion macros that test for the desired type in v before
 * homing sp and calling a conversion function.
 */
#define VALUE_TO_NUMBER(cx, v, d)                                             \
    JS_BEGIN_MACRO                                                            \
        if (JSVAL_IS_INT(v)) {                                                \
            d = (jsdouble)JSVAL_TO_INT(v);                                    \
        } else if (JSVAL_IS_DOUBLE(v)) {                                      \
            d = *JSVAL_TO_DOUBLE(v);                                          \
        } else {                                                              \
            SAVE_SP(fp);                                                      \
            ok = js_ValueToNumber(cx, v, &d);                                 \
            if (!ok)                                                          \
                goto out;                                                     \
        }                                                                     \
    JS_END_MACRO

#define POP_BOOLEAN(cx, v, b)                                                 \
    JS_BEGIN_MACRO                                                            \
        v = FETCH_OPND(-1);                                                   \
        if (v == JSVAL_NULL) {                                                \
            b = JS_FALSE;                                                     \
        } else if (JSVAL_IS_BOOLEAN(v)) {                                     \
            b = JSVAL_TO_BOOLEAN(v);                                          \
        } else {                                                              \
            SAVE_SP(fp);                                                      \
            ok = js_ValueToBoolean(cx, v, &b);                                \
            if (!ok)                                                          \
                goto out;                                                     \
        }                                                                     \
        sp--;                                                                 \
    JS_END_MACRO

#define VALUE_TO_OBJECT(cx, v, obj)                                           \
    JS_BEGIN_MACRO                                                            \
        if (JSVAL_IS_OBJECT(v) && v != JSVAL_NULL) {                          \
            obj = JSVAL_TO_OBJECT(v);                                         \
        } else {                                                              \
            SAVE_SP(fp);                                                      \
            obj = js_ValueToNonNullObject(cx, v);                             \
            if (!obj) {                                                       \
                ok = JS_FALSE;                                                \
                goto out;                                                     \
            }                                                                 \
        }                                                                     \
    JS_END_MACRO

#if JS_BUG_VOID_TOSTRING
#define CHECK_VOID_TOSTRING(cx, v)                                            \
    if (JSVAL_IS_VOID(v)) {                                                   \
        JSString *str_;                                                       \
        str_ = ATOM_TO_STRING(cx->runtime->atomState.typeAtoms[JSTYPE_VOID]); \
        v = STRING_TO_JSVAL(str_);                                            \
    }
#else
#define CHECK_VOID_TOSTRING(cx, v)  ((void)0)
#endif

#if JS_BUG_EAGER_TOSTRING
#define CHECK_EAGER_TOSTRING(hint)  (hint = JSTYPE_STRING)
#else
#define CHECK_EAGER_TOSTRING(hint)  ((void)0)
#endif

#define VALUE_TO_PRIMITIVE(cx, v, hint, vp)                                   \
    JS_BEGIN_MACRO                                                            \
        if (JSVAL_IS_PRIMITIVE(v)) {                                          \
            CHECK_VOID_TOSTRING(cx, v);                                       \
            *vp = v;                                                          \
        } else {                                                              \
            SAVE_SP(fp);                                                      \
            CHECK_EAGER_TOSTRING(hint);                                       \
            ok = OBJ_DEFAULT_VALUE(cx, JSVAL_TO_OBJECT(v), hint, vp);         \
            if (!ok)                                                          \
                goto out;                                                     \
        }                                                                     \
    JS_END_MACRO

JS_FRIEND_API(jsval *)
js_AllocRawStack(JSContext *cx, uintN nslots, void **markp)
{
    jsval *sp;

    if (markp)
        *markp = JS_ARENA_MARK(&cx->stackPool);
    JS_ARENA_ALLOCATE_CAST(sp, jsval *, &cx->stackPool, nslots * sizeof(jsval));
    if (!sp) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_STACK_OVERFLOW,
                             (cx->fp && cx->fp->fun)
                             ? JS_GetFunctionName(cx->fp->fun)
                             : "script");
    }
    return sp;
}

JS_FRIEND_API(void)
js_FreeRawStack(JSContext *cx, void *mark)
{
    JS_ARENA_RELEASE(&cx->stackPool, mark);
}

JS_FRIEND_API(jsval *)
js_AllocStack(JSContext *cx, uintN nslots, void **markp)
{
    jsval *sp, *vp, *end;
    JSArena *a;
    JSStackHeader *sh;
    JSStackFrame *fp;

    /* Callers don't check for zero nslots: we do to avoid empty segments. */
    if (nslots == 0) {
        *markp = NULL;
        return JS_ARENA_MARK(&cx->stackPool);