Ejemplo n.º 1
0
/* Returns whether the current PC has method JIT'd code. */
static inline void *
AtSafePoint(JSContext *cx)
{
    JSStackFrame *fp = cx->fp();
    if (fp->hasImacropc())
        return false;

    JSScript *script = fp->script();
    return script->maybeNativeCodeForPC(fp->isConstructing(), cx->regs->pc);
}
void JS_FASTCALL
stubs::EnterScript(VMFrame &f)
{
    JSStackFrame *fp = f.fp();
    JSContext *cx = f.cx;

    if (fp->script()->debugMode) {
        if (fp->isExecuteFrame()) {
            JSInterpreterHook hook = cx->debugHooks->executeHook;
            if (JS_UNLIKELY(hook != NULL))
                fp->setHookData(hook(cx, fp, JS_TRUE, 0, cx->debugHooks->executeHookData));
        } else {
            JSInterpreterHook hook = cx->debugHooks->callHook;
            if (JS_UNLIKELY(hook != NULL))
                fp->setHookData(hook(cx, fp, JS_TRUE, 0, cx->debugHooks->callHookData));
        }
    }

    Probes::enterJSFun(cx, fp->maybeFun(), fp->script());
}
Ejemplo n.º 3
0
/*
 * Interprets until either a safe point is reached that has method JIT'd
 * code, or the current frame tries to return.
 */
static inline JSBool
PartialInterpret(VMFrame &f)
{
    JSContext *cx = f.cx;
    JSStackFrame *fp = cx->fp();

#ifdef DEBUG
    JSScript *script = fp->script();
    JS_ASSERT(!fp->finishedInInterpreter());
    JS_ASSERT(fp->hasImacropc() ||
              !script->maybeNativeCodeForPC(fp->isConstructing(), cx->regs->pc));
#endif

    JSBool ok = JS_TRUE;
    ok = Interpret(cx, fp, 0, JSINTERP_SAFEPOINT);

    return ok;
}
void JS_FASTCALL
stubs::LeaveScript(VMFrame &f)
{
    JSStackFrame *fp = f.fp();
    JSContext *cx = f.cx;
    Probes::exitJSFun(cx, fp->maybeFun(), fp->maybeScript());

    if (fp->script()->debugMode) {
        void *hookData;
        JSInterpreterHook hook =
            fp->isExecuteFrame() ? cx->debugHooks->executeHook : cx->debugHooks->callHook;

        if (JS_UNLIKELY(hook != NULL) && (hookData = fp->maybeHookData())) {
            JSBool ok = JS_TRUE;
            hook(cx, fp, JS_FALSE, &ok, hookData);
            if (!ok)
                THROW();
        }
    }
}
Ejemplo n.º 5
0
/*
 * The strategy for this goes as follows:
 *
 * 1) Scan the stack, looking at all return addresses that could go into JIT
 *    code.
 * 2) If an address corresponds to a call site registered by |callSite| during
 *    the last compilation, remember it.
 * 3) Purge the old compiled state and return if there were no active frames of
 *    this script on the stack.
 * 4) Fix up the stack by replacing all saved addresses with the addresses the
 *    new compiler gives us for the call sites.
 */
bool
Recompiler::recompile()
{
    JS_ASSERT(script->hasJITCode());

    Vector<PatchableAddress> normalPatches(cx);
    Vector<PatchableAddress> ctorPatches(cx);

    JSStackFrame *firstCtorFrame = NULL;
    JSStackFrame *firstNormalFrame = NULL;

    // Find all JIT'd stack frames to account for return addresses that will
    // need to be patched after recompilation.
    for (VMFrame *f = script->compartment->jaegerCompartment->activeFrame();
            f != NULL;
            f = f->previous) {

        // Scan all frames owned by this VMFrame.
        JSStackFrame *end = f->entryfp->prev();
        for (JSStackFrame *fp = f->fp(); fp != end; fp = fp->prev()) {
            // Remember the latest frame for each type of JIT'd code, so the
            // compiler will have a frame to re-JIT from.
            if (!firstCtorFrame && fp->script() == script && fp->isConstructing())
                firstCtorFrame = fp;
            else if (!firstNormalFrame && fp->script() == script && !fp->isConstructing())
                firstNormalFrame = fp;

            void **addr = fp->addressOfNativeReturnAddress();
            if (script->jitCtor && script->jitCtor->isValidCode(*addr)) {
                if (!ctorPatches.append(findPatch(script->jitCtor, addr)))
                    return false;
            } else if (script->jitNormal && script->jitNormal->isValidCode(*addr)) {
                if (!normalPatches.append(findPatch(script->jitNormal, addr)))
                    return false;
            }
        }

        void **addr = f->returnAddressLocation();
        if (script->jitCtor && script->jitCtor->isValidCode(*addr)) {
            if (!ctorPatches.append(findPatch(script->jitCtor, addr)))
                return false;
        } else if (script->jitNormal && script->jitNormal->isValidCode(*addr)) {
            if (!normalPatches.append(findPatch(script->jitNormal, addr)))
                return false;
        }
    }

    Vector<CallSite> normalSites(cx);
    Vector<CallSite> ctorSites(cx);

    if (script->jitNormal && !saveTraps(script->jitNormal, &normalSites))
        return false;
    if (script->jitCtor && !saveTraps(script->jitCtor, &ctorSites))
        return false;

    ReleaseScriptCode(cx, script);

    if (normalPatches.length() &&
            !recompile(firstNormalFrame, normalPatches, normalSites)) {
        return false;
    }

    if (ctorPatches.length() &&
            !recompile(firstCtorFrame, ctorPatches, ctorSites)) {
        return false;
    }

    return true;
}
Ejemplo n.º 6
0
static JSBool
Exception(JSContext *cx, uintN argc, Value *vp)
{
    JSString *message, *filename;
    JSStackFrame *fp;

    /*
     * ECMA ed. 3, 15.11.1 requires Error, etc., to construct even when
     * called as functions, without operator new.  But as we do not give
     * each constructor a distinct JSClass, whose .name member is used by
     * NewNativeClassInstance to find the class prototype, we must get the
     * class prototype ourselves.
     */
    JSObject &callee = vp[0].toObject();
    Value protov;
    if (!callee.getProperty(cx, ATOM_TO_JSID(cx->runtime->atomState.classPrototypeAtom), &protov))
        return JS_FALSE;

    if (!protov.isObject()) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_BAD_PROTOTYPE, "Error");
        return JS_FALSE;
    }

    JSObject *errProto = &protov.toObject();
    JSObject *obj = NewNativeClassInstance(cx, &js_ErrorClass, errProto, errProto->getParent());
    if (!obj)
        return JS_FALSE;

    /*
     * If it's a new object of class Exception, then null out the private
     * data so that the finalizer doesn't attempt to free it.
     */
    if (obj->getClass() == &js_ErrorClass)
        obj->setPrivate(NULL);

    /* Set the 'message' property. */
    Value *argv = vp + 2;
    if (argc != 0 && !argv[0].isUndefined()) {
        message = js_ValueToString(cx, argv[0]);
        if (!message)
            return JS_FALSE;
        argv[0].setString(message);
    } else {
        message = NULL;
    }

    /* Set the 'fileName' property. */
    if (argc > 1) {
        filename = js_ValueToString(cx, argv[1]);
        if (!filename)
            return JS_FALSE;
        argv[1].setString(filename);
        fp = NULL;
    } else {
        fp = js_GetScriptedCaller(cx, NULL);
        if (fp) {
            filename = FilenameToString(cx, fp->script()->filename);
            if (!filename)
                return JS_FALSE;
        } else {
            filename = cx->runtime->emptyString;
        }
    }

    /* Set the 'lineNumber' property. */
    uint32_t lineno;
    if (argc > 2) {
        if (!ValueToECMAUint32(cx, argv[2], &lineno))
            return JS_FALSE;
    } else {
        if (!fp)
            fp = js_GetScriptedCaller(cx, NULL);
        lineno = (fp && fp->pc(cx)) ? js_FramePCToLineNumber(cx, fp) : 0;
    }

    if (obj->getClass() == &js_ErrorClass &&
            !InitExnPrivate(cx, obj, message, filename, lineno, NULL)) {
        return JS_FALSE;
    }

    vp->setObject(*obj);
    return JS_TRUE;
}
Ejemplo n.º 7
0
static jsbytecode *
FindExceptionHandler(JSContext *cx)
{
    JSStackFrame *fp = cx->fp();
    JSScript *script = fp->script();

top:
    if (cx->isExceptionPending() && JSScript::isValidOffset(script->trynotesOffset)) {
        // The PC is updated before every stub call, so we can use it here.
        unsigned offset = cx->regs->pc - script->main;

        JSTryNoteArray *tnarray = script->trynotes();
        for (unsigned i = 0; i < tnarray->length; ++i) {
            JSTryNote *tn = &tnarray->vector[i];

            // The following if condition actually tests two separate conditions:
            //   (1) offset - tn->start >= tn->length
            //       means the PC is not in the range of this try note, so we
            //       should continue searching, after considering:
            //   (2) offset - tn->start == tn->length
            //       means the PC is at the first op of the exception handler
            //       for this try note. This happens when an exception is thrown
            //       during recording: the interpreter sets the PC to the handler
            //       and then exits. In this case, we are in fact at the right
            //       exception handler. 
            //      
            //       Hypothetically, the op we are at might have thrown an
            //       exception, in which case this would not be the right handler.
            //       But the first ops of exception handlers generated by our
            //       bytecode compiler cannot throw, so this is not possible.
            if (offset - tn->start > tn->length)
                continue;
            if (tn->stackDepth > cx->regs->sp - fp->base())
                continue;

            jsbytecode *pc = script->main + tn->start + tn->length;
            JSBool ok = js_UnwindScope(cx, tn->stackDepth, JS_TRUE);
            JS_ASSERT(cx->regs->sp == fp->base() + tn->stackDepth);

            switch (tn->kind) {
                case JSTRY_CATCH:
                  JS_ASSERT(js_GetOpcode(cx, fp->script(), pc) == JSOP_ENTERBLOCK);

#if JS_HAS_GENERATORS
                  /* Catch cannot intercept the closing of a generator. */
                  if (JS_UNLIKELY(cx->getPendingException().isMagic(JS_GENERATOR_CLOSING)))
                      break;
#endif

                  /*
                   * Don't clear cx->throwing to save cx->exception from GC
                   * until it is pushed to the stack via [exception] in the
                   * catch block.
                   */
                  return pc;

                case JSTRY_FINALLY:
                  /*
                   * Push (true, exception) pair for finally to indicate that
                   * [retsub] should rethrow the exception.
                   */
                  cx->regs->sp[0].setBoolean(true);
                  cx->regs->sp[1] = cx->getPendingException();
                  cx->regs->sp += 2;
                  cx->clearPendingException();
                  return pc;

                case JSTRY_ITER:
                {
                  /*
                   * This is similar to JSOP_ENDITER in the interpreter loop,
                   * except the code now uses the stack slot normally used by
                   * JSOP_NEXTITER, namely regs.sp[-1] before the regs.sp -= 2
                   * adjustment and regs.sp[1] after, to save and restore the
                   * pending exception.
                   */
                  Value v = cx->getPendingException();
                  JS_ASSERT(js_GetOpcode(cx, fp->script(), pc) == JSOP_ENDITER);
                  cx->clearPendingException();
                  ok = !!js_CloseIterator(cx, &cx->regs->sp[-1].toObject());
                  cx->regs->sp -= 1;
                  if (!ok)
                      goto top;
                  cx->setPendingException(v);
                }
            }
        }
    }

    return NULL;
}
Ejemplo n.º 8
0
extern "C" void *
js_InternalThrow(VMFrame &f)
{
    JSContext *cx = f.cx;

    // It's possible that from within RunTracer(), Interpret() returned with
    // an error and finished the frame (i.e., called ScriptEpilogue), but has
    // not yet performed an inline return.
    //
    // In this case, RunTracer() has no choice but to propagate the error
    // up to the method JIT, and thus to this function. But ScriptEpilogue()
    // has already been called. Detect this, and avoid double-finishing the
    // frame. See HandleErrorInExcessFrame() and bug 624100.
    if (f.fp()->finishedInInterpreter()) {
        // If it's the last frame, just propagate the failure up again.
        if (f.fp() == f.entryfp)
            return NULL;

        InlineReturn(f);
    }

    // Make sure sp is up to date.
    JS_ASSERT(cx->regs == &f.regs);

    // Call the throw hook if necessary
    JSThrowHook handler = f.cx->debugHooks->throwHook;
    if (handler) {
        Value rval;
        switch (handler(cx, cx->fp()->script(), cx->regs->pc, Jsvalify(&rval),
                        cx->debugHooks->throwHookData)) {
          case JSTRAP_ERROR:
            cx->clearPendingException();
            return NULL;

          case JSTRAP_RETURN:
            cx->clearPendingException();
            cx->fp()->setReturnValue(rval);
            return JS_FUNC_TO_DATA_PTR(void *,
                   cx->jaegerCompartment()->forceReturnTrampoline());

          case JSTRAP_THROW:
            cx->setPendingException(rval);
            break;

          default:
            break;
        }
    }

    jsbytecode *pc = NULL;
    for (;;) {
        pc = FindExceptionHandler(cx);
        if (pc)
            break;

        // The JIT guarantees that ScriptEpilogue() has always been run
        // upon exiting to its caller. This is important for consistency,
        // where execution modes make similar guarantees about prologues
        // and epilogues. RunTracer(), Interpret(), and Invoke() all
        // rely on this property.
        JS_ASSERT(!f.fp()->finishedInInterpreter());
        js_UnwindScope(cx, 0, cx->isExceptionPending());
        ScriptEpilogue(f.cx, f.fp(), false);

        // Don't remove the last frame, this is the responsibility of
        // JaegerShot()'s caller. We only guarantee that ScriptEpilogue()
        // has been run.
        if (f.entryfp == f.fp())
            break;

        JS_ASSERT(f.regs.sp == cx->regs->sp);
        InlineReturn(f);
    }

    JS_ASSERT(f.regs.sp == cx->regs->sp);

    if (!pc)
        return NULL;

    JSStackFrame *fp = cx->fp();
    JSScript *script = fp->script();
    return script->nativeCodeForPC(fp->isConstructing(), pc);
}