jsopcode.c

java script test programing source code

    saveop = JSOP_NOP;
    sn = NULL;
    rval = NULL;
#if JS_HAS_XML_SUPPORT
    foreach = inXML = quoteAttr = JS_FALSE;
#endif

    while (nb < 0 || pc < endpc) {
        /*
         * Move saveop to lastop so prefixed bytecodes can take special action
         * while sharing maximal code.  Set op and saveop to the new bytecode,
         * use op in POP_STR to trigger automatic parenthesization, but push
         * saveop at the bottom of the loop if this op pushes.  Thus op may be
         * set to nop or otherwise mutated to suppress auto-parens.
         */
        lastop = saveop;
        op = saveop = (JSOp) *pc;
        cs = &js_CodeSpec[saveop];
        len = oplen = cs->length;

        if (nb < 0 && -(nb + 1) == (intN)ss->top - cs->nuses + cs->ndefs)
            return pc;

        if (pc + oplen == jp->dvgfence) {
            JSStackFrame *fp;
            uint32 format, mode, type;

            /*
             * Rewrite non-get ops to their "get" format if the error is in
             * the bytecode at pc, so we don't decompile more than the error
             * expression.
             */
            for (fp = cx->fp; fp && !fp->script; fp = fp->down)
                continue;
            format = cs->format;
            if (((fp && pc == fp->pc) ||
                 (pc == startpc && cs->nuses != 0)) &&
                format & (JOF_SET|JOF_DEL|JOF_INCDEC|JOF_IMPORT|JOF_FOR)) {
                mode = (format & JOF_MODEMASK);
                if (mode == JOF_NAME) {
                    /*
                     * JOF_NAME does not imply JOF_CONST, so we must check for
                     * the QARG and QVAR format types, and translate those to
                     * JSOP_GETARG or JSOP_GETVAR appropriately, instead of to
                     * JSOP_NAME.
                     */
                    type = format & JOF_TYPEMASK;
                    op = (type == JOF_QARG)
                         ? JSOP_GETARG
                         : (type == JOF_QVAR)
                         ? JSOP_GETVAR
                         : (type == JOF_LOCAL)
                         ? JSOP_GETLOCAL
                         : JSOP_NAME;

                    i = cs->nuses - js_CodeSpec[op].nuses;
                    while (--i >= 0)
                        PopOff(ss, JSOP_NOP);
                } else {
                    /*
                     * We must replace the faulting pc's bytecode with a
                     * corresponding JSOP_GET* code.  For JSOP_SET{PROP,ELEM},
                     * we must use the "2nd" form of JSOP_GET{PROP,ELEM}, to
                     * throw away the assignment op's right-hand operand and
                     * decompile it as if it were a GET of its left-hand
                     * operand.
                     */
                    if (mode == JOF_PROP) {
                        op = (format & JOF_SET) ? JSOP_GETPROP2 : JSOP_GETPROP;
                    } else if (mode == JOF_ELEM) {
                        op = (format & JOF_SET) ? JSOP_GETELEM2 : JSOP_GETELEM;
                    } else {
                        /*
                         * Zero mode means precisely that op is uncategorized
                         * for our purposes, so we must write per-op special
                         * case code here.
                         */
                        switch (op) {
                          case JSOP_ENUMELEM:
                          case JSOP_ENUMCONSTELEM:
                            op = JSOP_GETELEM;
                            break;
#if JS_HAS_LVALUE_RETURN
                          case JSOP_SETCALL:
                            op = JSOP_CALL;
                            break;
#endif
                          default:
                            LOCAL_ASSERT(0);
                        }
                    }
                }
            }

            saveop = op;
            if (op >= JSOP_LIMIT) {
                switch (op) {
                  case JSOP_GETPROP2:
                    saveop = JSOP_GETPROP;
                    break;
                  case JSOP_GETELEM2:
                    saveop = JSOP_GETELEM;
                    break;
                  default:;
                }
            }
            LOCAL_ASSERT(js_CodeSpec[saveop].length == oplen);

            jp->dvgfence = NULL;
        }

        if (cs->token) {
            switch (cs->nuses) {
              case 2:
                sn = js_GetSrcNote(jp->script, pc);
                if (sn && SN_TYPE(sn) == SRC_ASSIGNOP) {
                    /*
                     * Avoid over-parenthesizing y in x op= y based on its
                     * expansion: x = x op y (replace y by z = w to see the
                     * problem).
                     */
                    op = pc[oplen];
                    LOCAL_ASSERT(op != saveop);
                }
                rval = POP_STR();
                lval = POP_STR();
                if (op != saveop) {
                    /* Print only the right operand of the assignment-op. */
                    todo = SprintCString(&ss->sprinter, rval);
                    op = saveop;
                } else if (!inXML) {
                    todo = Sprint(&ss->sprinter, "%s %s %s",
                                  lval, cs->token, rval);
                } else {
                    /* In XML, just concatenate the two operands. */
                    LOCAL_ASSERT(op == JSOP_ADD);
                    todo = Sprint(&ss->sprinter, ss_format, lval, rval);
                }
                break;

              case 1:
                rval = POP_STR();
                todo = Sprint(&ss->sprinter, ss_format, cs->token, rval);
                break;

              case 0:
                todo = SprintCString(&ss->sprinter, cs->token);
                break;

              default:
                todo = -2;
                break;
            }
        } else {
            switch (op) {
#define BEGIN_LITOPX_CASE(OP)                                                 \
              case OP:                                                        \
                atomIndex = GET_ATOM_INDEX(pc);                               \
              do_##OP:                                                        \
                atom = js_GetAtom(cx, &jp->script->atomMap, atomIndex);

#define END_LITOPX_CASE                                                       \
                break;

              case JSOP_NOP:
                /*
                 * Check for a do-while loop, a for-loop with an empty
                 * initializer part, a labeled statement, a function
                 * definition, or try/finally.
                 */
                sn = js_GetSrcNote(jp->script, pc);
                todo = -2;
                switch (sn ? SN_TYPE(sn) : SRC_NULL) {
                  case SRC_WHILE:
                    js_printf(SET_MAYBE_BRACE(jp), "\tdo {\n");
                    jp->indent += 4;
                    break;

                  case SRC_FOR:
                    rval = "";

                  do_forloop:
                    /* Skip the JSOP_NOP or JSOP_POP bytecode. */
                    pc++;

                    /* Get the cond, next, and loop-closing tail offsets. */
                    cond = js_GetSrcNoteOffset(sn, 0);
                    next = js_GetSrcNoteOffset(sn, 1);
                    tail = js_GetSrcNoteOffset(sn, 2);
                    LOCAL_ASSERT(tail + GetJumpOffset(pc+tail, pc+tail) == 0);

                    /* Print the keyword and the possibly empty init-part. */
                    js_printf(jp, "\tfor (%s;", rval);

                    if (pc[cond] == JSOP_IFEQ || pc[cond] == JSOP_IFEQX) {
                        /* Decompile the loop condition. */
                        DECOMPILE_CODE(pc, cond);
                        js_printf(jp, " %s", POP_STR());
                    }

                    /* Need a semicolon whether or not there was a cond. */
                    js_puts(jp, ";");

                    if (pc[next] != JSOP_GOTO && pc[next] != JSOP_GOTOX) {
                        /* Decompile the loop updater. */
                        DECOMPILE_CODE(pc + next, tail - next - 1);
                        js_printf(jp, " %s", POP_STR());
                    }

                    /* Do the loop body. */
                    js_printf(SET_MAYBE_BRACE(jp), ") {\n");
                    jp->indent += 4;
                    oplen = (cond) ? js_CodeSpec[pc[cond]].length : 0;
                    DECOMPILE_CODE(pc + cond + oplen, next - cond - oplen);
                    jp->indent -= 4;
                    js_printf(jp, "\t}\n");

                    /* Set len so pc skips over the entire loop. */
                    len = tail + js_CodeSpec[pc[tail]].length;
                    break;

                  case SRC_LABEL:
                    atom = js_GetAtom(cx, &jp->script->atomMap,
                                      (jsatomid) js_GetSrcNoteOffset(sn, 0));
                    jp->indent -= 4;
                    rval = QuoteString(&ss->sprinter, ATOM_TO_STRING(atom), 0);
                    if (!rval)
                        return NULL;
                    RETRACT(&ss->sprinter, rval);
                    js_printf(CLEAR_MAYBE_BRACE(jp), "\t%s:\n", rval);
                    jp->indent += 4;
                    break;

                  case SRC_LABELBRACE:
                    atom = js_GetAtom(cx, &jp->script->atomMap,
                                      (jsatomid) js_GetSrcNoteOffset(sn, 0));
                    rval = QuoteString(&ss->sprinter, ATOM_TO_STRING(atom), 0);
                    if (!rval)
                        return NULL;
                    RETRACT(&ss->sprinter, rval);
                    js_printf(CLEAR_MAYBE_BRACE(jp), "\t%s: {\n", rval);
                    jp->indent += 4;
                    break;

                  case SRC_ENDBRACE:
                    jp->indent -= 4;
                    js_printf(jp, "\t}\n");
                    break;

                  case SRC_FUNCDEF:
                    atom = js_GetAtom(cx, &jp->script->atomMap,
                                      (jsatomid) js_GetSrcNoteOffset(sn, 0));
                    LOCAL_ASSERT(ATOM_IS_OBJECT(atom));
                  do_function:
                    obj = ATOM_TO_OBJECT(atom);
                    fun = (JSFunction *) JS_GetPrivate(cx, obj);
                    jp2 = js_NewPrinter(cx, JS_GetFunctionName(fun),
                                        jp->indent, jp->pretty);
                    if (!jp2)
                        return NULL;
                    jp2->scope = jp->scope;
                    js_puts(jp2, "\n");
                    ok = js_DecompileFunction(jp2, fun);
                    if (ok) {
                        js_puts(jp2, "\n");
                        str = js_GetPrinterOutput(jp2);
                        if (str)
                            js_printf(jp, "%s\n", JS_GetStringBytes(str));
                        else
                            ok = JS_FALSE;
                    }
                    js_DestroyPrinter(jp2);
                    if (!ok)
                        return NULL;

                    break;

                  case SRC_BRACE:
                    js_printf(CLEAR_MAYBE_BRACE(jp), "\t{\n");
                    jp->indent += 4;
                    len = js_GetSrcNoteOffset(sn, 0);
                    DECOMPILE_CODE(pc + oplen, len - oplen);
                    jp->indent -= 4;
                    js_printf(jp, "\t}\n");
                    break;

                  default:;
                }
                break;

              case JSOP_GROUP:
                cs = &js_CodeSpec[lastop];
                if ((cs->prec != 0 &&
                     cs->prec == js_CodeSpec[pc[JSOP_GROUP_LENGTH]].prec) ||
                    pc[JSOP_GROUP_LENGTH] == JSOP_PUSHOBJ ||
                    pc[JSOP_GROUP_LENGTH] == JSOP_DUP) {
                    /*
                     * Force parens if this JSOP_GROUP forced re-association
                     * against precedence, or if this is a call or constructor
                     * expression, or if it is destructured (JSOP_DUP).
                     *
                     * This is necessary to handle the operator new grammar,
                     * by which new x(y).z means (new x(y))).z.  For example
                     * new (x(y).z) must decompile with the constructor
                     * parenthesized, but normal precedence has JSOP_GETPROP
                     * (for the final .z) higher than JSOP_NEW.  In general,
                     * if the call or constructor expression is parenthesized,
                     * we preserve parens.
                     */
                    op = JSOP_NAME;
                    rval = POP_STR();
                    todo = SprintCString(&ss->sprinter, rval);
                } else {
                    /*
                     * Don't explicitly parenthesize -- just fix the top
                     * opcode so that the auto-parens magic in PopOff can do
                     * its thing.
                     */
                    LOCAL_ASSERT(ss->top != 0);
                    ss->opcodes[ss->top-1] = saveop = lastop;
                    todo = -2;
                }
                break;

              case JSOP_STARTITER:
                todo = -2;
                break;

              case JSOP_PUSH:
#if JS_HAS_DESTRUCTURING
                sn = js_GetSrcNote(jp->script, pc);
                if (sn && SN_TYPE(sn) == SRC_GROUPASSIGN) {
                    pc = DecompileGroupAssignment(ss, pc, endpc, sn, &todo);
                    if (!pc)
                        return NULL;
                    LOCAL_ASSERT(*pc == JSOP_SETSP);
                    len = oplen = JSOP_SETSP_LENGTH;
                    goto end_groupassignment;
                }
#endif
                /* FALL THROUGH */

              case JSOP_PUSHOBJ:
              case JSOP_BINDNAME:
              do_JSOP_BINDNAME:
                todo = Sprint(&ss->sprinter, "");
                break;

              case JSOP_TRY:
                js_printf(CLEAR_MAYBE_BRACE(jp), "\ttry {\n");
                jp->indent += 4;
                todo = -2;
                break;

              case JSOP_FINALLY:
                jp->indent -= 4;
                js_printf(CLEAR_MAYBE_BRACE(jp), "\t} finally {\n");
                jp->indent += 4;

                /*
                 * We must push an empty string placeholder for gosub's return
                 * address, popped by JSOP_RETSUB and counted by script->depth
                 * but not by ss->top (see JSOP_SETSP, below).
                 */
                todo = Sprint(&ss->sprinter, exception_cookie);
                if (todo < 0 || !PushOff(ss, todo, op))
                    return NULL;
                todo = Sprint(&ss->sprinter, retsub_pc_cookie);
                break;

              case JSOP_RETSUB:
                rval = POP_STR();
                LOCAL_ASSERT(strcmp(rval, retsub_pc_cookie) == 0);
                lval = POP_STR();
                LOCAL_ASSERT(strcmp(lval, exception_cookie) == 0);
                todo = -2;
                break;

              case JSOP_SWAP:
                /*
                 * We don't generate this opcode currently, and previously we
                 * did not need to decompile it.  If old, serialized bytecode
                 * uses it still, we should fall through and set todo = -2.
                 */
                /* FALL THROUGH */

              case JSOP_GOSUB:
              case JSOP_GOSUBX:
                /*
                 * JSOP_GOSUB and GOSUBX have no effect on the decompiler's
                 * string stack because the next op in bytecode order finds
                 * the stack balanced by a JSOP_RETSUB executed elsewhere.
                 */
                todo = -2;
                break;

              case JSOP_SETSP: