jsparse.c

java script test programing source code

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sw=4 et tw=78:
 *
 * ***** 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
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 * the provisions above, a recipient may use your version of this file under
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 * ***** END LICENSE BLOCK ***** */

/*
 * JS parser.
 *
 * This is a recursive-descent parser for the JavaScript language specified by
 * "The JavaScript 1.5 Language Specification".  It uses lexical and semantic
 * feedback to disambiguate non-LL(1) structures.  It generates trees of nodes
 * induced by the recursive parsing (not precise syntax trees, see jsparse.h).
 * After tree construction, it rewrites trees to fold constants and evaluate
 * compile-time expressions.  Finally, it calls js_EmitTree (see jsemit.h) to
 * generate bytecode.
 *
 * This parser attempts no error recovery.
 */
#include "jsstddef.h"
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "jstypes.h"
#include "jsarena.h" /* Added by JSIFY */
#include "jsutil.h" /* Added by JSIFY */
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsconfig.h"
#include "jsemit.h"
#include "jsfun.h"
#include "jsinterp.h"
#include "jslock.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsparse.h"
#include "jsscan.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstr.h"

#if JS_HAS_XML_SUPPORT
#include "jsxml.h"
#endif

#if JS_HAS_DESTRUCTURING
#include "jsdhash.h"
#endif

/*
 * JS parsers, from lowest to highest precedence.
 *
 * Each parser takes a context, a token stream, and a tree context struct.
 * Each returns a parse node tree or null on error.
 */

typedef JSParseNode *
JSParser(JSContext *cx, JSTokenStream *ts, JSTreeContext *tc);

typedef JSParseNode *
JSMemberParser(JSContext *cx, JSTokenStream *ts, JSTreeContext *tc,
               JSBool allowCallSyntax);

typedef JSParseNode *
JSPrimaryParser(JSContext *cx, JSTokenStream *ts, JSTreeContext *tc,
                JSTokenType tt, JSBool afterDot);

static JSParser FunctionStmt;
static JSParser FunctionExpr;
static JSParser Statements;
static JSParser Statement;
static JSParser Variables;
static JSParser Expr;
static JSParser AssignExpr;
static JSParser CondExpr;
static JSParser OrExpr;
static JSParser AndExpr;
static JSParser BitOrExpr;
static JSParser BitXorExpr;
static JSParser BitAndExpr;
static JSParser EqExpr;
static JSParser RelExpr;
static JSParser ShiftExpr;
static JSParser AddExpr;
static JSParser MulExpr;
static JSParser UnaryExpr;
static JSMemberParser MemberExpr;
static JSPrimaryParser PrimaryExpr;

/*
 * Insist that the next token be of type tt, or report errno and return null.
 * NB: this macro uses cx and ts from its lexical environment.
 */
#define MUST_MATCH_TOKEN(tt, errno)                                           \
    JS_BEGIN_MACRO                                                            \
        if (js_GetToken(cx, ts) != tt) {                                      \
            js_ReportCompileErrorNumber(cx, ts, JSREPORT_TS | JSREPORT_ERROR, \
                            errno);                                           \
            return NULL;                                                      \
        }                                                                     \
    JS_END_MACRO

#define CHECK_RECURSION()                                                     \
    JS_BEGIN_MACRO                                                            \
        int stackDummy;                                                       \
        if (!JS_CHECK_STACK_SIZE(cx, stackDummy)) {                           \
            js_ReportCompileErrorNumber(cx, ts, JSREPORT_TS | JSREPORT_ERROR, \
                                        JSMSG_OVER_RECURSED);                 \
            return NULL;                                                      \
        }                                                                     \
    JS_END_MACRO

#ifdef METER_PARSENODES
static uint32 parsenodes = 0;
static uint32 maxparsenodes = 0;
static uint32 recyclednodes = 0;
#endif

static JSParseNode *
RecycleTree(JSParseNode *pn, JSTreeContext *tc)
{
    JSParseNode *next;

    if (!pn)
        return NULL;
    JS_ASSERT(pn != tc->nodeList);      /* catch back-to-back dup recycles */
    next = pn->pn_next;
    pn->pn_next = tc->nodeList;
    tc->nodeList = pn;
#ifdef METER_PARSENODES
    recyclednodes++;
#endif
    return next;
}

static JSParseNode *
NewOrRecycledNode(JSContext *cx, JSTreeContext *tc)
{
    JSParseNode *pn;

    pn = tc->nodeList;
    if (!pn) {
        JS_ARENA_ALLOCATE_TYPE(pn, JSParseNode, &cx->tempPool);
        if (!pn)
            JS_ReportOutOfMemory(cx);
    } else {
        tc->nodeList = pn->pn_next;

        /* Recycle immediate descendents only, to save work and working set. */
        switch (pn->pn_arity) {
          case PN_FUNC:
            RecycleTree(pn->pn_body, tc);
            break;
          case PN_LIST:
            if (pn->pn_head) {
                /* XXX check for dup recycles in the list */
                *pn->pn_tail = tc->nodeList;
                tc->nodeList = pn->pn_head;
#ifdef METER_PARSENODES
                recyclednodes += pn->pn_count;
#endif
            }
            break;
          case PN_TERNARY:
            RecycleTree(pn->pn_kid1, tc);
            RecycleTree(pn->pn_kid2, tc);
            RecycleTree(pn->pn_kid3, tc);
            break;
          case PN_BINARY:
            RecycleTree(pn->pn_left, tc);
            RecycleTree(pn->pn_right, tc);
            break;
          case PN_UNARY:
            RecycleTree(pn->pn_kid, tc);
            break;
          case PN_NAME:
            RecycleTree(pn->pn_expr, tc);
            break;
          case PN_NULLARY:
            break;
        }
    }
#ifdef METER_PARSENODES
    if (pn) {
        parsenodes++;
        if (parsenodes - recyclednodes > maxparsenodes)
            maxparsenodes = parsenodes - recyclednodes;
    }
#endif
    return pn;
}

/*
 * Allocate a JSParseNode from cx's temporary arena.
 */
static JSParseNode *
NewParseNode(JSContext *cx, JSTokenStream *ts, JSParseNodeArity arity,
             JSTreeContext *tc)
{
    JSParseNode *pn;
    JSToken *tp;

    pn = NewOrRecycledNode(cx, tc);
    if (!pn)
        return NULL;
    tp = &CURRENT_TOKEN(ts);
    pn->pn_type = tp->type;
    pn->pn_pos = tp->pos;
    pn->pn_op = JSOP_NOP;
    pn->pn_arity = arity;
    pn->pn_next = NULL;
    pn->pn_ts = ts;
    pn->pn_source = NULL;
    return pn;
}

static JSParseNode *
NewBinary(JSContext *cx, JSTokenType tt,
          JSOp op, JSParseNode *left, JSParseNode *right,
          JSTreeContext *tc)
{
    JSParseNode *pn, *pn1, *pn2;

    if (!left || !right)
        return NULL;

    /*
     * Flatten a left-associative (left-heavy) tree of a given operator into
     * a list, to reduce js_FoldConstants and js_EmitTree recursion.
     */
    if (left->pn_type == tt &&
        left->pn_op == op &&
        (js_CodeSpec[op].format & JOF_LEFTASSOC)) {
        if (left->pn_arity != PN_LIST) {
            pn1 = left->pn_left, pn2 = left->pn_right;
            left->pn_arity = PN_LIST;
            PN_INIT_LIST_1(left, pn1);
            PN_APPEND(left, pn2);
            if (tt == TOK_PLUS) {
                if (pn1->pn_type == TOK_STRING)
                    left->pn_extra |= PNX_STRCAT;
                else if (pn1->pn_type != TOK_NUMBER)
                    left->pn_extra |= PNX_CANTFOLD;
                if (pn2->pn_type == TOK_STRING)
                    left->pn_extra |= PNX_STRCAT;
                else if (pn2->pn_type != TOK_NUMBER)
                    left->pn_extra |= PNX_CANTFOLD;
            }
        }
        PN_APPEND(left, right);
        left->pn_pos.end = right->pn_pos.end;
        if (tt == TOK_PLUS) {
            if (right->pn_type == TOK_STRING)
                left->pn_extra |= PNX_STRCAT;
            else if (right->pn_type != TOK_NUMBER)
                left->pn_extra |= PNX_CANTFOLD;
        }
        return left;
    }

    /*
     * Fold constant addition immediately, to conserve node space and, what's
     * more, so js_FoldConstants never sees mixed addition and concatenation
     * operations with more than one leading non-string operand in a PN_LIST
     * generated for expressions such as 1 + 2 + "pt" (which should evaluate
     * to "3pt", not "12pt").
     */
    if (tt == TOK_PLUS &&
        left->pn_type == TOK_NUMBER &&
        right->pn_type == TOK_NUMBER) {
        left->pn_dval += right->pn_dval;
        left->pn_pos.end = right->pn_pos.end;
        RecycleTree(right, tc);
        return left;
    }

    pn = NewOrRecycledNode(cx, tc);
    if (!pn)
        return NULL;
    pn->pn_type = tt;
    pn->pn_pos.begin = left->pn_pos.begin;
    pn->pn_pos.end = right->pn_pos.end;
    pn->pn_op = op;
    pn->pn_arity = PN_BINARY;
    pn->pn_left = left;
    pn->pn_right = right;
    pn->pn_next = NULL;
    pn->pn_ts = NULL;
    pn->pn_source = NULL;
    return pn;
}

#if JS_HAS_GETTER_SETTER
static JSTokenType
CheckGetterOrSetter(JSContext *cx, JSTokenStream *ts, JSTokenType tt)
{
    JSAtom *atom;
    JSRuntime *rt;
    JSOp op;
    const char *name;

    JS_ASSERT(CURRENT_TOKEN(ts).type == TOK_NAME);
    atom = CURRENT_TOKEN(ts).t_atom;
    rt = cx->runtime;
    if (atom == rt->atomState.getterAtom)
        op = JSOP_GETTER;
    else if (atom == rt->atomState.setterAtom)
        op = JSOP_SETTER;
    else
        return TOK_NAME;
    if (js_PeekTokenSameLine(cx, ts) != tt)
        return TOK_NAME;
    (void) js_GetToken(cx, ts);
    if (CURRENT_TOKEN(ts).t_op != JSOP_NOP) {
        js_ReportCompileErrorNumber(cx, ts, JSREPORT_TS | JSREPORT_ERROR,
                                    JSMSG_BAD_GETTER_OR_SETTER,
                                    (op == JSOP_GETTER)
                                    ? js_getter_str
                                    : js_setter_str);
        return TOK_ERROR;
    }
    CURRENT_TOKEN(ts).t_op = op;
    if (JS_HAS_STRICT_OPTION(cx)) {
        name = js_AtomToPrintableString(cx, atom);
        if (!name ||
            !js_ReportCompileErrorNumber(cx, ts,
                                         JSREPORT_TS |
                                         JSREPORT_WARNING |
                                         JSREPORT_STRICT,
                                         JSMSG_DEPRECATED_USAGE,
                                         name)) {
            return TOK_ERROR;
        }
    }
    return tt;
}
#endif

static void
MaybeSetupFrame(JSContext *cx, JSObject *chain, JSStackFrame *oldfp,
                JSStackFrame *newfp)
{
    /*
     * Always push a new frame if the current frame is special, so that
     * Variables gets the correct variables object: the one from the special
     * frame's caller.
     */
    if (oldfp &&
        oldfp->varobj &&
        oldfp->scopeChain == chain &&
        !(oldfp->flags & JSFRAME_SPECIAL)) {