jsopcode.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 ***** */

/*
 * JS bytecode descriptors, disassemblers, and decompilers.
 */
#include "jsstddef.h"
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "jstypes.h"
#include "jsarena.h" /* Added by JSIFY */
#include "jsutil.h" /* Added by JSIFY */
#include "jsdtoa.h"
#include "jsprf.h"
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsconfig.h"
#include "jsdbgapi.h"
#include "jsemit.h"
#include "jsfun.h"
#include "jslock.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstr.h"

const char js_const_str[]       = "const";
const char js_var_str[]         = "var";
const char js_function_str[]    = "function";
const char js_in_str[]          = "in";
const char js_instanceof_str[]  = "instanceof";
const char js_new_str[]         = "new";
const char js_delete_str[]      = "delete";
const char js_typeof_str[]      = "typeof";
const char js_void_str[]        = "void";
const char js_null_str[]        = "null";
const char js_this_str[]        = "this";
const char js_false_str[]       = "false";
const char js_true_str[]        = "true";

const char *js_incop_str[]      = {"++", "--"};

/* Pollute the namespace locally for MSVC Win16, but not for WatCom.  */
#ifdef __WINDOWS_386__
    #ifdef FAR
        #undef FAR
    #endif
#else  /* !__WINDOWS_386__ */
#ifndef FAR
#define FAR
#endif
#endif /* !__WINDOWS_386__ */

const JSCodeSpec FAR js_CodeSpec[] = {
#define OPDEF(op,val,name,token,length,nuses,ndefs,prec,format) \
    {name,token,length,nuses,ndefs,prec,format},
#include "jsopcode.tbl"
#undef OPDEF
};

uintN js_NumCodeSpecs = sizeof (js_CodeSpec) / sizeof js_CodeSpec[0];

/************************************************************************/

static ptrdiff_t
GetJumpOffset(jsbytecode *pc, jsbytecode *pc2)
{
    uint32 type;
    
    type = (js_CodeSpec[*pc].format & JOF_TYPEMASK);
    if (JOF_TYPE_IS_EXTENDED_JUMP(type))
        return GET_JUMPX_OFFSET(pc2);
    return GET_JUMP_OFFSET(pc2);
}

#ifdef DEBUG

JS_FRIEND_API(void)
js_Disassemble(JSContext *cx, JSScript *script, JSBool lines, FILE *fp)
{
    jsbytecode *pc, *end;
    uintN len;

    pc = script->code;
    end = pc + script->length;
    while (pc < end) {
        if (pc == script->main)
            fputs("main:\n", fp);
        len = js_Disassemble1(cx, script, pc,
                              PTRDIFF(pc, script->code, jsbytecode),
                              lines, fp);
        if (!len)
            return;
        pc += len;
    }
}

JS_FRIEND_API(uintN)
js_Disassemble1(JSContext *cx, JSScript *script, jsbytecode *pc, uintN loc,
                JSBool lines, FILE *fp)
{
    JSOp op;
    const JSCodeSpec *cs;
    ptrdiff_t len, off, jmplen;
    uint32 type;
    JSAtom *atom;
    JSString *str;
    char *cstr;

    op = (JSOp)*pc;
    if (op >= JSOP_LIMIT) {
        char numBuf1[12], numBuf2[12];
        JS_snprintf(numBuf1, sizeof numBuf1, "%d", op);
        JS_snprintf(numBuf2, sizeof numBuf2, "%d", JSOP_LIMIT);
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                             JSMSG_BYTECODE_TOO_BIG, numBuf1, numBuf2);
        return 0;
    }
    cs = &js_CodeSpec[op];
    len = (intN)cs->length;
    fprintf(fp, "%05u:", loc);
    if (lines)
        fprintf(fp, "%4u", JS_PCToLineNumber(cx, script, pc));
    fprintf(fp, "  %s", cs->name);
    type = cs->format & JOF_TYPEMASK;
    switch (type) {
      case JOF_BYTE:
        if (op == JSOP_TRAP) {
            op = JS_GetTrapOpcode(cx, script, pc);
            if (op == JSOP_LIMIT)
                return 0;
            len = (intN)js_CodeSpec[op].length;
        }
        break;

      case JOF_JUMP:
      case JOF_JUMPX:
        off = GetJumpOffset(pc, pc);
        fprintf(fp, " %td (%td)", loc + off, off);
        break;

      case JOF_CONST:
        atom = GET_ATOM(cx, script, pc);
        str = js_ValueToSource(cx, ATOM_KEY(atom));
        if (!str)
            return 0;
        cstr = js_DeflateString(cx, JSSTRING_CHARS(str), JSSTRING_LENGTH(str));
        if (!cstr)
            return 0;
        fprintf(fp, " %s", cstr);
        JS_free(cx, cstr);
        break;

      case JOF_UINT16:
        fprintf(fp, " %u", GET_ARGC(pc));
        break;

#if JS_HAS_SWITCH_STATEMENT
      case JOF_TABLESWITCH:
      case JOF_TABLESWITCHX:
      {
        jsbytecode *pc2;
        jsint i, low, high;

        jmplen = (type == JOF_TABLESWITCH) ? JUMP_OFFSET_LEN
                                           : JUMPX_OFFSET_LEN;
        pc2 = pc;
        off = GetJumpOffset(pc, pc2);
        pc2 += jmplen;
        low = GET_JUMP_OFFSET(pc2);
        pc2 += JUMP_OFFSET_LEN;
        high = GET_JUMP_OFFSET(pc2);
        pc2 += JUMP_OFFSET_LEN;
        fprintf(fp, " defaultOffset %td low %d high %d", off, low, high);
        for (i = low; i <= high; i++) {
            off = GetJumpOffset(pc, pc2);
            fprintf(fp, "\n\t%d: %td", i, off);
            pc2 += jmplen;
        }
        len = 1 + pc2 - pc;
        break;
      }

      case JOF_LOOKUPSWITCH:
      case JOF_LOOKUPSWITCHX:
      {
        jsbytecode *pc2;
        jsint npairs;

        jmplen = (type == JOF_LOOKUPSWITCH) ? JUMP_OFFSET_LEN
                                            : JUMPX_OFFSET_LEN;
        pc2 = pc;
        off = GetJumpOffset(pc, pc2);
        pc2 += jmplen;
        npairs = (jsint) GET_ATOM_INDEX(pc2);
        pc2 += ATOM_INDEX_LEN;
        fprintf(fp, " offset %td npairs %u", off, (uintN) npairs);
        while (npairs) {
            atom = GET_ATOM(cx, script, pc2);
            pc2 += ATOM_INDEX_LEN;
            off = GetJumpOffset(pc, pc2);
            pc2 += jmplen;

            str = js_ValueToSource(cx, ATOM_KEY(atom));
            if (!str)
                return 0;
            cstr = js_DeflateString(cx, JSSTRING_CHARS(str),
                                    JSSTRING_LENGTH(str));
            if (!cstr)
                return 0;
            fprintf(fp, "\n\t%s: %td", cstr, off);
            JS_free(cx, cstr);
            npairs--;
        }
        len = 1 + pc2 - pc;
        break;
      }
#endif /* JS_HAS_SWITCH_STATEMENT */

      case JOF_QARG:
        fprintf(fp, " %u", GET_ARGNO(pc));
        break;

      case JOF_QVAR:
        fprintf(fp, " %u", GET_VARNO(pc));
        break;

#if JS_HAS_LEXICAL_CLOSURE
      case JOF_DEFLOCALVAR:
        fprintf(fp, " %u", GET_VARNO(pc));
        pc += VARNO_LEN;
        atom = GET_ATOM(cx, script, pc);
        str = js_ValueToSource(cx, ATOM_KEY(atom));
        if (!str)
            return 0;
        cstr = js_DeflateString(cx, JSSTRING_CHARS(str), JSSTRING_LENGTH(str));
        if (!cstr)
            return 0;
        fprintf(fp, " %s", cstr);
        JS_free(cx, cstr);
        break;
#endif

      default: {
        char numBuf[12];
        JS_snprintf(numBuf, sizeof numBuf, "%lx", (unsigned long) cs->format);
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                             JSMSG_UNKNOWN_FORMAT, numBuf);
        return 0;
      }
    }
    fputs("\n", fp);
    return len;
}

#endif /* DEBUG */

/************************************************************************/

/*
 * Sprintf, but with unlimited and automatically allocated buffering.
 */
typedef struct Sprinter {
    JSContext       *context;       /* context executing the decompiler */
    JSArenaPool     *pool;          /* string allocation pool */
    char            *base;          /* base address of buffer in pool */
    size_t          size;           /* size of buffer allocated at base */
    ptrdiff_t       offset;         /* offset of next free char in buffer */
} Sprinter;

#define INIT_SPRINTER(cx, sp, ap, off) \
    ((sp)->context = cx, (sp)->pool = ap, (sp)->base = NULL, (sp)->size = 0,  \
     (sp)->offset = off)

#define OFF2STR(sp,off) ((sp)->base + (off))
#define STR2OFF(sp,str) ((str) - (sp)->base)
#define RETRACT(sp,str) ((sp)->offset = STR2OFF(sp, str))

static JSBool
SprintAlloc(Sprinter *sp, size_t nb)
{
    if (!sp->base) {
        JS_ARENA_ALLOCATE_CAST(sp->base, char *, sp->pool, nb);
    } else {
        JS_ARENA_GROW_CAST(sp->base, char *, sp->pool, sp->size, nb);
    }
    if (!sp->base) {
        JS_ReportOutOfMemory(sp->context);
        return JS_FALSE;
    }
    sp->size += nb;
    return JS_TRUE;
}

static ptrdiff_t
SprintPut(Sprinter *sp, const char *s, size_t len)
{
    ptrdiff_t nb, offset;
    char *bp;

    /* Allocate space for s, including the '\0' at the end. */
    nb = (sp->offset + len + 1) - sp->size;
    if (nb > 0 && !SprintAlloc(sp, nb))
        return -1;

    /* Advance offset and copy s into sp's buffer. */
    offset = sp->offset;
    sp->offset += len;
    bp = sp->base + offset;
    memmove(bp, s, len);
    bp[len] = 0;
    return offset;
}

static ptrdiff_t
Sprint(Sprinter *sp, const char *format, ...)
{
    va_list ap;
    char *bp;
    ptrdiff_t offset;

    va_start(ap, format);
    bp = JS_vsmprintf(format, ap);	/* XXX vsaprintf */
    va_end(ap);
    if (!bp) {
        JS_ReportOutOfMemory(sp->context);
        return -1;
    }
    offset = SprintPut(sp, bp, strlen(bp));
    free(bp);
    return offset;
}

const jschar js_EscapeMap[] = {
    '\b', 'b',
    '\f', 'f',
    '\n', 'n',