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jsopcode.cpp
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jsopcode.cpp
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set sw=4 ts=8 et tw=99:
*
* ***** 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.
*/
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "jstypes.h"
#include "jsstdint.h"
#include "jsarena.h"
#include "jsutil.h"
#include "jsprf.h"
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsversion.h"
#include "jsemit.h"
#include "jsfun.h"
#include "jsiter.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsregexp.h"
#include "jsscan.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstr.h"
#include "jsstaticcheck.h"
#include "jsvector.h"
#include "jsobjinlines.h"
#include "jsscriptinlines.h"
#include "jscntxtinlines.h"
#include "jsautooplen.h"
using namespace js;
using namespace js::gc;
/*
* Index limit must stay within 32 bits.
*/
JS_STATIC_ASSERT(sizeof(uint32) * JS_BITS_PER_BYTE >= INDEX_LIMIT_LOG2 + 1);
/* Verify JSOP_XXX_LENGTH constant definitions. */
#define OPDEF(op,val,name,token,length,nuses,ndefs,prec,format) \
JS_STATIC_ASSERT(op##_LENGTH == length);
#include "jsopcode.tbl"
#undef OPDEF
static const char js_incop_strs[][3] = {"++", "--"};
static const char js_for_each_str[] = "for each";
const JSCodeSpec js_CodeSpec[] = {
#define OPDEF(op,val,name,token,length,nuses,ndefs,prec,format) \
{length,nuses,ndefs,prec,format},
#include "jsopcode.tbl"
#undef OPDEF
};
uintN js_NumCodeSpecs = JS_ARRAY_LENGTH(js_CodeSpec);
/*
* Each element of the array is either a source literal associated with JS
* bytecode or null.
*/
static const char *CodeToken[] = {
#define OPDEF(op,val,name,token,length,nuses,ndefs,prec,format) \
token,
#include "jsopcode.tbl"
#undef OPDEF
};
#if defined(DEBUG) || defined(JS_JIT_SPEW) || defined(JS_METHODJIT_SPEW)
/*
* Array of JS bytecode names used by DEBUG-only js_Disassemble and by
* JIT debug spew.
*/
const char *js_CodeName[] = {
#define OPDEF(op,val,name,token,length,nuses,ndefs,prec,format) \
name,
#include "jsopcode.tbl"
#undef OPDEF
};
#endif
/************************************************************************/
static ptrdiff_t
GetJumpOffset(jsbytecode *pc, jsbytecode *pc2)
{
uint32 type;
type = JOF_OPTYPE(*pc);
if (JOF_TYPE_IS_EXTENDED_JUMP(type))
return GET_JUMPX_OFFSET(pc2);
return GET_JUMP_OFFSET(pc2);
}
uintN
js_GetIndexFromBytecode(JSContext *cx, JSScript *script, jsbytecode *pc,
ptrdiff_t pcoff)
{
JSOp op;
uintN span, base;
op = js_GetOpcode(cx, script, pc);
JS_ASSERT(js_CodeSpec[op].length >= 1 + pcoff + UINT16_LEN);
/*
* We need to detect index base prefix. It presents when resetbase
* follows the bytecode.
*/
span = js_CodeSpec[op].length;
base = 0;
if (pc - script->code + span < script->length) {
if (pc[span] == JSOP_RESETBASE) {
base = GET_INDEXBASE(pc - JSOP_INDEXBASE_LENGTH);
} else if (pc[span] == JSOP_RESETBASE0) {
JS_ASSERT(JSOP_INDEXBASE1 <= pc[-1] || pc[-1] <= JSOP_INDEXBASE3);
base = (pc[-1] - JSOP_INDEXBASE1 + 1) << 16;
}
}
return base + GET_UINT16(pc + pcoff);
}
uintN
js_GetVariableBytecodeLength(jsbytecode *pc)
{
JSOp op;
uintN jmplen, ncases;
jsint low, high;
op = (JSOp) *pc;
JS_ASSERT(js_CodeSpec[op].length == -1);
switch (op) {
case JSOP_TABLESWITCHX:
jmplen = JUMPX_OFFSET_LEN;
goto do_table;
case JSOP_TABLESWITCH:
jmplen = JUMP_OFFSET_LEN;
do_table:
/* Structure: default-jump case-low case-high case1-jump ... */
pc += jmplen;
low = GET_JUMP_OFFSET(pc);
pc += JUMP_OFFSET_LEN;
high = GET_JUMP_OFFSET(pc);
ncases = (uintN)(high - low + 1);
return 1 + jmplen + INDEX_LEN + INDEX_LEN + ncases * jmplen;
case JSOP_LOOKUPSWITCHX:
jmplen = JUMPX_OFFSET_LEN;
goto do_lookup;
default:
JS_ASSERT(op == JSOP_LOOKUPSWITCH);
jmplen = JUMP_OFFSET_LEN;
do_lookup:
/* Structure: default-jump case-count (case1-value case1-jump) ... */
pc += jmplen;
ncases = GET_UINT16(pc);
return 1 + jmplen + INDEX_LEN + ncases * (INDEX_LEN + jmplen);
}
}
uintN
js_GetVariableStackUses(JSOp op, jsbytecode *pc)
{
JS_ASSERT(*pc == op || *pc == JSOP_TRAP);
JS_ASSERT(js_CodeSpec[op].nuses == -1);
switch (op) {
case JSOP_POPN:
return GET_UINT16(pc);
case JSOP_LEAVEBLOCK:
return GET_UINT16(pc);
case JSOP_LEAVEBLOCKEXPR:
return GET_UINT16(pc) + 1;
default:
/* stack: fun, this, [argc arguments] */
JS_ASSERT(op == JSOP_NEW || op == JSOP_CALL || op == JSOP_EVAL ||
op == JSOP_FUNCALL || op == JSOP_FUNAPPLY);
return 2 + GET_ARGC(pc);
}
}
uintN
js_GetEnterBlockStackDefs(JSContext *cx, JSScript *script, jsbytecode *pc)
{
JSObject *obj;
JS_ASSERT(*pc == JSOP_ENTERBLOCK || *pc == JSOP_TRAP);
GET_OBJECT_FROM_BYTECODE(script, pc, 0, obj);
return OBJ_BLOCK_COUNT(cx, obj);
}
class AutoScriptUntrapper {
JSContext *cx;
JSScript *script;
jsbytecode *origPC;
jsbytecode *newPC;
public:
AutoScriptUntrapper(JSContext *cx, JSScript *script, jsbytecode **pc)
: cx(cx), script(script), origPC(*pc)
{
jsbytecode *newCode = js_UntrapScriptCode(cx, script);
if (newCode == script->code) {
// No change needed
newPC = origPC;
} else {
script->main += newCode - script->code;
*pc = newPC = origPC + (newCode - script->code);
script->code = newCode;
}
}
~AutoScriptUntrapper()
{
ptrdiff_t delta = newPC - origPC;
if (delta) {
jsbytecode *oldCode = script->code - delta;
cx->free_(script->code);
script->code = oldCode;
script->main -= delta;
}
}
};
#ifdef DEBUG
/*
* If pc != NULL, include a prefix indicating whether the PC is at the current line.
* If counts != NULL, include a counter of the number of times each op was executed.
*/
JS_FRIEND_API(JSBool)
js_DisassembleAtPC(JSContext *cx, JSScript *script, JSBool lines, jsbytecode *pc, int* counts, Sprinter *sp)
{
jsbytecode *next, *end;
uintN len;
if (counts)
SprintCString(sp, "count x ");
SprintCString(sp, "off ");
if (lines)
SprintCString(sp, "line");
SprintCString(sp, " op\n");
if (counts)
SprintCString(sp, "-------- ");
SprintCString(sp, "----- ");
if (lines)
SprintCString(sp, "----");
SprintCString(sp, " --\n");
next = script->code;
end = next + script->length;
while (next < end) {
if (next == script->main)
SprintCString(sp, "main:\n");
if (pc != NULL) {
if (pc == next)
SprintCString(sp, "--> ");
else
SprintCString(sp, " ");
}
len = js_Disassemble1(cx, script, next,
next - script->code,
lines, sp, counts);
if (!len)
return JS_FALSE;
next += len;
}
return JS_TRUE;
}
JS_FRIEND_API(JSBool)
js_Disassemble(JSContext *cx, JSScript *script, JSBool lines, Sprinter *sp, int* counts)
{
return js_DisassembleAtPC(cx, script, lines, NULL, counts, sp);
}
JS_FRIEND_API(JSBool)
js_DumpPC(JSContext *cx, int* counts = NULL)
{
void *mark = JS_ARENA_MARK(&cx->tempPool);
Sprinter sprinter;
INIT_SPRINTER(cx, &sprinter, &cx->tempPool, 0);
JSBool ok = js_DisassembleAtPC(cx, cx->fp()->script(), true, cx->regs().pc, counts, &sprinter);
fprintf(stdout, "%s", sprinter.base);
JS_ARENA_RELEASE(&cx->tempPool, mark);
return ok;
}
JSBool
js_DumpScript(JSContext *cx, JSScript *script)
{
void *mark = JS_ARENA_MARK(&cx->tempPool);
Sprinter sprinter;
INIT_SPRINTER(cx, &sprinter, &cx->tempPool, 0);
JSBool ok = js_Disassemble(cx, script, true, &sprinter);
fprintf(stdout, "%s", sprinter.base);
JS_ARENA_RELEASE(&cx->tempPool, mark);
return ok;
}
static bool
ToDisassemblySource(JSContext *cx, jsval v, JSAutoByteString *bytes)
{
if (!JSVAL_IS_PRIMITIVE(v)) {
JSObject *obj = JSVAL_TO_OBJECT(v);
Class *clasp = obj->getClass();
if (clasp == &js_BlockClass) {
char *source = JS_sprintf_append(NULL, "depth %d {", OBJ_BLOCK_DEPTH(cx, obj));
if (!source)
return false;
Shape::Range r = obj->lastProperty()->all();
while (!r.empty()) {
const Shape &shape = r.front();
JSAutoByteString bytes;
if (!js_AtomToPrintableString(cx, JSID_TO_ATOM(shape.propid), &bytes))
return false;
r.popFront();
source = JS_sprintf_append(source, "%s: %d%s",
bytes.ptr(), shape.shortid,
!r.empty() ? ", " : "");
if (!source)
return false;
}
source = JS_sprintf_append(source, "}");
if (!source)
return false;
bytes->initBytes(source);
return true;
}
if (clasp == &js_FunctionClass) {
JSFunction *fun = GET_FUNCTION_PRIVATE(cx, obj);
JSString *str = JS_DecompileFunction(cx, fun, JS_DONT_PRETTY_PRINT);
if (!str)
return false;
return bytes->encode(cx, str);
}
if (clasp == &js_RegExpClass) {
AutoValueRooter tvr(cx);
if (!js_regexp_toString(cx, obj, tvr.addr()))
return false;
return bytes->encode(cx, JSVAL_TO_STRING(Jsvalify(tvr.value())));
}
}
return !!js_ValueToPrintable(cx, Valueify(v), bytes, true);
}
JS_FRIEND_API(uintN)
js_Disassemble1(JSContext *cx, JSScript *script, jsbytecode *pc,
uintN loc, JSBool lines, Sprinter *sp, int* counts)
{
JSOp op;
const JSCodeSpec *cs;
ptrdiff_t len, off, jmplen;
uint32 type;
JSAtom *atom;
uintN index;
JSObject *obj;
jsval v;
jsint i;
AutoScriptUntrapper untrapper(cx, script, &pc);
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 = (ptrdiff_t) cs->length;
Sprint(sp, "%05u:", loc);
if (counts)
Sprint(sp, "% 8d x ", counts[loc]);
if (lines)
Sprint(sp, "%4u", JS_PCToLineNumber(cx, script, pc));
Sprint(sp, " %s", js_CodeName[op]);
type = JOF_TYPE(cs->format);
switch (type) {
case JOF_BYTE:
break;
case JOF_JUMP:
case JOF_JUMPX:
off = GetJumpOffset(pc, pc);
Sprint(sp, " %u (%d)", loc + intN(off), intN(off));
break;
case JOF_ATOM:
case JOF_OBJECT:
case JOF_REGEXP:
index = js_GetIndexFromBytecode(cx, script, pc, 0);
if (type == JOF_ATOM) {
if (op == JSOP_DOUBLE) {
v = Jsvalify(script->getConst(index));
} else {
JS_GET_SCRIPT_ATOM(script, pc, index, atom);
v = STRING_TO_JSVAL(atom);
}
} else {
if (type == JOF_OBJECT)
obj = script->getObject(index);
else
obj = script->getRegExp(index);
v = OBJECT_TO_JSVAL(obj);
}
{
JSAutoByteString bytes;
if (!ToDisassemblySource(cx, v, &bytes))
return 0;
Sprint(sp, " %s", bytes.ptr());
}
break;
case JOF_GLOBAL:
atom = script->getGlobalAtom(GET_SLOTNO(pc));
v = STRING_TO_JSVAL(atom);
{
JSAutoByteString bytes;
if (!ToDisassemblySource(cx, v, &bytes))
return 0;
Sprint(sp, " %s", bytes.ptr());
}
break;
case JOF_UINT16PAIR:
i = (jsint)GET_UINT16(pc);
Sprint(sp, " %d", i);
pc += UINT16_LEN;
/* FALL THROUGH */
case JOF_UINT16:
i = (jsint)GET_UINT16(pc);
goto print_int;
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;
Sprint(sp, " defaultOffset %d low %d high %d", intN(off), low, high);
for (i = low; i <= high; i++) {
off = GetJumpOffset(pc, pc2);
Sprint(sp, "\n\t%d: %d", i, intN(off));
pc2 += jmplen;
}
len = 1 + pc2 - pc;
break;
}
case JOF_LOOKUPSWITCH:
case JOF_LOOKUPSWITCHX:
{
jsbytecode *pc2;
jsatomid npairs;
jmplen = (type == JOF_LOOKUPSWITCH) ? JUMP_OFFSET_LEN
: JUMPX_OFFSET_LEN;
pc2 = pc;
off = GetJumpOffset(pc, pc2);
pc2 += jmplen;
npairs = GET_UINT16(pc2);
pc2 += UINT16_LEN;
Sprint(sp, " offset %d npairs %u", intN(off), uintN(npairs));
while (npairs) {
uint16 constIndex = GET_INDEX(pc2);
pc2 += INDEX_LEN;
off = GetJumpOffset(pc, pc2);
pc2 += jmplen;
JSAutoByteString bytes;
if (!ToDisassemblySource(cx, Jsvalify(script->getConst(constIndex)), &bytes))
return 0;
Sprint(sp, "\n\t%s: %d", bytes.ptr(), intN(off));
npairs--;
}
len = 1 + pc2 - pc;
break;
}
case JOF_QARG:
Sprint(sp, " %u", GET_ARGNO(pc));
break;
case JOF_LOCAL:
Sprint(sp, " %u", GET_SLOTNO(pc));
break;
case JOF_SLOTATOM:
case JOF_SLOTOBJECT: {
Sprint(sp, " %u", GET_SLOTNO(pc));
index = js_GetIndexFromBytecode(cx, script, pc, SLOTNO_LEN);
if (type == JOF_SLOTATOM) {
JS_GET_SCRIPT_ATOM(script, pc, index, atom);
v = STRING_TO_JSVAL(atom);
} else {
obj = script->getObject(index);
v = OBJECT_TO_JSVAL(obj);
}
JSAutoByteString bytes;
if (!ToDisassemblySource(cx, v, &bytes))
return 0;
Sprint(sp, " %s", bytes.ptr());
break;
}
case JOF_UINT24:
JS_ASSERT(op == JSOP_UINT24 || op == JSOP_NEWARRAY);
i = (jsint)GET_UINT24(pc);
goto print_int;
case JOF_UINT8:
i = pc[1];
goto print_int;
case JOF_INT8:
i = GET_INT8(pc);
goto print_int;
case JOF_INT32:
JS_ASSERT(op == JSOP_INT32);
i = GET_INT32(pc);
print_int:
Sprint(sp, " %d", i);
break;
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;
}
}
SprintCString(sp, "\n");
return len;
}
#endif /* DEBUG */
/************************************************************************/
#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
SprintEnsureBuffer(Sprinter *sp, size_t len)
{
ptrdiff_t nb;
char *base;
nb = (sp->offset + len + 1) - sp->size;
if (nb < 0)
return JS_TRUE;
base = sp->base;
if (!base) {
JS_ARENA_ALLOCATE_CAST(base, char *, sp->pool, nb);
} else {
JS_ARENA_GROW_CAST(base, char *, sp->pool, sp->size, nb);
}
if (!base) {
js_ReportOutOfScriptQuota(sp->context);
return JS_FALSE;
}
sp->base = base;
sp->size += nb;
return JS_TRUE;
}
namespace js {
char *
SprintReserveAmount(Sprinter *sp, size_t len)
{
/* Allocate space for s, including the '\0' at the end. */
if (!SprintEnsureBuffer(sp, len))
return NULL;
/* Advance offset and return the previous offset for caller to fill. */
ptrdiff_t offset = sp->offset;
sp->offset += len;
return sp->base + offset;
}
ptrdiff_t
SprintPut(Sprinter *sp, const char *s, size_t len)
{
ptrdiff_t offset = sp->size; /* save old size */
char *bp = sp->base; /* save old base */
/* Allocate space for s, including the '\0' at the end. */
if (!SprintEnsureBuffer(sp, len))
return -1;
if (sp->base != bp && /* buffer was realloc'ed */
s >= bp && s < bp + offset) { /* s was within the buffer */
s = sp->base + (s - bp); /* this is where it lives now */
}
/* 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;
}
ptrdiff_t
SprintCString(Sprinter *sp, const char *s)
{
return SprintPut(sp, s, strlen(s));
}
ptrdiff_t
SprintString(Sprinter *sp, JSString *str)
{
size_t length = str->length();
const jschar *chars = str->getChars(sp->context);
if (!chars)
return -1;
size_t size = js_GetDeflatedStringLength(sp->context, chars, length);
if (size == (size_t)-1 || !SprintEnsureBuffer(sp, size))
return -1;
ptrdiff_t offset = sp->offset;
sp->offset += size;
js_DeflateStringToBuffer(sp->context, chars, length, sp->base + offset,
&size);
sp->base[sp->offset] = 0;
return offset;
}
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 = SprintCString(sp, bp);
sp->context->free_(bp);
return offset;
}
} // namespace js
const char js_EscapeMap[] = {
'\b', 'b',
'\f', 'f',
'\n', 'n',
'\r', 'r',
'\t', 't',
'\v', 'v',
'"', '"',
'\'', '\'',
'\\', '\\',
'\0', '0'
};
#define DONT_ESCAPE 0x10000
static char *
QuoteString(Sprinter *sp, JSString *str, uint32 quote)
{
/* Sample off first for later return value pointer computation. */
JSBool dontEscape = (quote & DONT_ESCAPE) != 0;
jschar qc = (jschar) quote;
ptrdiff_t off = sp->offset;
if (qc && Sprint(sp, "%c", (char)qc) < 0)
return NULL;
const jschar *s = str->getChars(sp->context);
if (!s)
return NULL;
const jschar *z = s + str->length();
/* Loop control variables: z points at end of string sentinel. */
for (const jschar *t = s; t < z; s = ++t) {
/* Move t forward from s past un-quote-worthy characters. */
jschar c = *t;
while (JS_ISPRINT(c) && c != qc && c != '\\' && c != '\t' &&
!(c >> 8)) {
c = *++t;
if (t == z)
break;
}
ptrdiff_t len = t - s;
/* Allocate space for s, including the '\0' at the end. */
if (!SprintEnsureBuffer(sp, len))
return NULL;
/* Advance sp->offset and copy s into sp's buffer. */
char *bp = sp->base + sp->offset;
sp->offset += len;
while (--len >= 0)
*bp++ = (char) *s++;
*bp = '\0';
if (t == z)
break;
/* Use js_EscapeMap, \u, or \x only if necessary. */
bool ok;
const char *e;
if (!(c >> 8) && (e = strchr(js_EscapeMap, (int)c)) != NULL) {
ok = dontEscape
? Sprint(sp, "%c", (char)c) >= 0
: Sprint(sp, "\\%c", e[1]) >= 0;
} else {
/*
* Use \x only if the high byte is 0 and we're in a quoted string,
* because ECMA-262 allows only \u, not \x, in Unicode identifiers
* (see bug 621814).
*/
ok = Sprint(sp, (qc && !(c >> 8)) ? "\\x%02X" : "\\u%04X", c) >= 0;
}
if (!ok)
return NULL;
}
/* Sprint the closing quote and return the quoted string. */
if (qc && Sprint(sp, "%c", (char)qc) < 0)
return NULL;
/*
* If we haven't Sprint'd anything yet, Sprint an empty string so that
* the OFF2STR below gives a valid result.
*/
if (off == sp->offset && Sprint(sp, "") < 0)
return NULL;
return OFF2STR(sp, off);
}
JSString *
js_QuoteString(JSContext *cx, JSString *str, jschar quote)
{
void *mark;
Sprinter sprinter;
char *bytes;
JSString *escstr;
mark = JS_ARENA_MARK(&cx->tempPool);
INIT_SPRINTER(cx, &sprinter, &cx->tempPool, 0);
bytes = QuoteString(&sprinter, str, quote);
escstr = bytes ? JS_NewStringCopyZ(cx, bytes) : NULL;
JS_ARENA_RELEASE(&cx->tempPool, mark);
return escstr;
}
/************************************************************************/
struct JSPrinter {
Sprinter sprinter; /* base class state */
JSArenaPool pool; /* string allocation pool */
uintN indent; /* indentation in spaces */
bool pretty; /* pretty-print: indent, use newlines */
bool grouped; /* in parenthesized expression context */
bool strict; /* in code marked strict */
JSScript *script; /* script being printed */
jsbytecode *dvgfence; /* DecompileExpression fencepost */
jsbytecode **pcstack; /* DecompileExpression modeled stack */
JSFunction *fun; /* interpreted function */
jsuword *localNames; /* argument and variable names */
};
JSPrinter *
js_NewPrinter(JSContext *cx, const char *name, JSFunction *fun,
uintN indent, JSBool pretty, JSBool grouped, JSBool strict)
{
JSPrinter *jp;
jp = (JSPrinter *) cx->malloc_(sizeof(JSPrinter));
if (!jp)
return NULL;
INIT_SPRINTER(cx, &jp->sprinter, &jp->pool, 0);
JS_InitArenaPool(&jp->pool, name, 256, 1, &cx->scriptStackQuota);
jp->indent = indent;
jp->pretty = !!pretty;
jp->grouped = !!grouped;
jp->strict = !!strict;
jp->script = NULL;
jp->dvgfence = NULL;
jp->pcstack = NULL;
jp->fun = fun;
jp->localNames = NULL;
if (fun && fun->isInterpreted() && fun->script()->bindings.hasLocalNames()) {
jp->localNames = fun->script()->bindings.getLocalNameArray(cx, &jp->pool);
if (!jp->localNames) {
js_DestroyPrinter(jp);
return NULL;
}
}
return jp;
}
void
js_DestroyPrinter(JSPrinter *jp)
{
JS_FinishArenaPool(&jp->pool);
jp->sprinter.context->free_(jp);
}
JSString *
js_GetPrinterOutput(JSPrinter *jp)
{
JSContext *cx;
JSString *str;
cx = jp->sprinter.context;
if (!jp->sprinter.base)
return cx->runtime->emptyString;
str = JS_NewStringCopyZ(cx, jp->sprinter.base);
if (!str)
return NULL;
JS_FreeArenaPool(&jp->pool);
INIT_SPRINTER(cx, &jp->sprinter, &jp->pool, 0);
return str;
}
/*
* NB: Indexed by SRC_DECL_* defines from jsemit.h.
*/
static const char * const var_prefix[] = {"var ", "const ", "let "};
static const char *
VarPrefix(jssrcnote *sn)
{
if (sn && (SN_TYPE(sn) == SRC_DECL || SN_TYPE(sn) == SRC_GROUPASSIGN)) {
ptrdiff_t type = js_GetSrcNoteOffset(sn, 0);
if ((uintN)type <= SRC_DECL_LET)
return var_prefix[type];
}
return "";
}
int
js_printf(JSPrinter *jp, const char *format, ...)
{
va_list ap;
char *bp, *fp;
int cc;
if (*format == '\0')
return 0;
va_start(ap, format);
/* If pretty-printing, expand magic tab into a run of jp->indent spaces. */
if (*format == '\t') {
format++;
if (jp->pretty && Sprint(&jp->sprinter, "%*s", jp->indent, "") < 0) {
va_end(ap);
return -1;
}
}
/* Suppress newlines (must be once per format, at the end) if not pretty. */
fp = NULL;
if (!jp->pretty && format[cc = strlen(format) - 1] == '\n') {
fp = JS_strdup(jp->sprinter.context, format);
if (!fp) {
va_end(ap);
return -1;
}
fp[cc] = '\0';
format = fp;
}
/* Allocate temp space, convert format, and put. */
bp = JS_vsmprintf(format, ap); /* XXX vsaprintf */
if (fp) {
jp->sprinter.context->free_(fp);
format = NULL;
}
if (!bp) {
JS_ReportOutOfMemory(jp->sprinter.context);
va_end(ap);
return -1;
}
cc = strlen(bp);
if (SprintPut(&jp->sprinter, bp, (size_t)cc) < 0)
cc = -1;
jp->sprinter.context->free_(bp);
va_end(ap);
return cc;
}
JSBool
js_puts(JSPrinter *jp, const char *s)
{
return SprintCString(&jp->sprinter, s) >= 0;
}
/************************************************************************/
typedef struct SprintStack {
Sprinter sprinter; /* sprinter for postfix to infix buffering */
ptrdiff_t *offsets; /* stack of postfix string offsets */
jsbytecode *opcodes; /* parallel stack of JS opcodes */
uintN top; /* top of stack index */
uintN inArrayInit; /* array initialiser/comprehension level */
JSBool inGenExp; /* in generator expression */
JSPrinter *printer; /* permanent output goes here */
} SprintStack;
/*
* Find the depth of the operand stack when the interpreter reaches the given
* pc in script. pcstack must have space for least script->depth elements. On
* return it will contain pointers to opcodes that populated the interpreter's
* current operand stack.
*
* This function cannot raise an exception or error. However, due to a risk of
* potential bugs when modeling the stack, the function returns -1 if it
* detects an inconsistency in the model. Such an inconsistency triggers an
* assert in a debug build.
*/
static intN
ReconstructPCStack(JSContext *cx, JSScript *script, jsbytecode *pc,
jsbytecode **pcstack);
#define FAILED_EXPRESSION_DECOMPILER ((char *) 1)