js/src/jsdbgapi.cpp
author Steve Fink <sfink@mozilla.com>
Tue, 18 Dec 2012 17:33:25 -0800
changeset 125594 f7fee43555d8239fd483ea0efc66a0fefe4cd6f2
parent 125270 18bc32f799d15288898e6f94abd7d0e5585a7373
child 125595 86a66542eaaff9858b2b2c69553f18bd194c18c8
permissions -rw-r--r--
Bug 822831 - Do not use Unrooted in a signal handler. r=billm

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sw=4 et tw=99:
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * JS debugging API.
 */

#include "mozilla/DebugOnly.h"

#include <string.h>
#include "jsprvtd.h"
#include "jstypes.h"
#include "jsutil.h"
#include "jsclist.h"
#include "jsapi.h"
#include "jscntxt.h"
#include "jsversion.h"
#include "jsdbgapi.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsinterp.h"
#include "jslock.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstr.h"
#include "jswatchpoint.h"
#include "jswrapper.h"

#include "gc/Marking.h"
#include "frontend/BytecodeEmitter.h"
#include "frontend/Parser.h"
#include "vm/Debugger.h"
#include "ion/Ion.h"

#include "jsatominlines.h"
#include "jsinferinlines.h"
#include "jsobjinlines.h"
#include "jsinterpinlines.h"
#include "jsscopeinlines.h"
#include "jsscriptinlines.h"

#include "vm/Stack-inl.h"

#include "jsautooplen.h"

using namespace js;
using namespace js::gc;

using mozilla::DebugOnly;

JS_PUBLIC_API(JSBool)
JS_GetDebugMode(JSContext *cx)
{
    return cx->compartment->debugMode();
}

JS_PUBLIC_API(JSBool)
JS_SetDebugMode(JSContext *cx, JSBool debug)
{
    return JS_SetDebugModeForCompartment(cx, cx->compartment, debug);
}

JS_PUBLIC_API(void)
JS_SetRuntimeDebugMode(JSRuntime *rt, JSBool debug)
{
    rt->debugMode = !!debug;
}

JSTrapStatus
js::ScriptDebugPrologue(JSContext *cx, StackFrame *fp)
{
    JS_ASSERT(fp == cx->fp());

    if (fp->isFramePushedByExecute()) {
        if (JSInterpreterHook hook = cx->runtime->debugHooks.executeHook)
            fp->setHookData(hook(cx, Jsvalify(fp), true, 0, cx->runtime->debugHooks.executeHookData));
    } else {
        if (JSInterpreterHook hook = cx->runtime->debugHooks.callHook)
            fp->setHookData(hook(cx, Jsvalify(fp), true, 0, cx->runtime->debugHooks.callHookData));
    }

    Value rval;
    JSTrapStatus status = Debugger::onEnterFrame(cx, &rval);
    switch (status) {
      case JSTRAP_CONTINUE:
        break;
      case JSTRAP_THROW:
        cx->setPendingException(rval);
        break;
      case JSTRAP_ERROR:
        cx->clearPendingException();
        break;
      case JSTRAP_RETURN:
        fp->setReturnValue(rval);
        break;
      default:
        JS_NOT_REACHED("bad Debugger::onEnterFrame JSTrapStatus value");
    }
    return status;
}

bool
js::ScriptDebugEpilogue(JSContext *cx, StackFrame *fp, bool okArg)
{
    JS_ASSERT(fp == cx->fp());
    JSBool ok = okArg;

    if (void *hookData = fp->maybeHookData()) {
        if (fp->isFramePushedByExecute()) {
            if (JSInterpreterHook hook = cx->runtime->debugHooks.executeHook)
                hook(cx, Jsvalify(fp), false, &ok, hookData);
        } else {
            if (JSInterpreterHook hook = cx->runtime->debugHooks.callHook)
                hook(cx, Jsvalify(fp), false, &ok, hookData);
        }
    }

    return Debugger::onLeaveFrame(cx, ok);
}

JS_FRIEND_API(JSBool)
JS_SetDebugModeForAllCompartments(JSContext *cx, JSBool debug)
{
    AutoDebugModeGC dmgc(cx->runtime);

    for (CompartmentsIter c(cx->runtime); !c.done(); c.next()) {
        // Ignore special compartments (atoms, JSD compartments)
        if (c->principals) {
            if (!c->setDebugModeFromC(cx, !!debug, dmgc))
                return false;
        }
    }
    return true;
}

JS_FRIEND_API(JSBool)
JS_SetDebugModeForCompartment(JSContext *cx, JSCompartment *comp, JSBool debug)
{
    AutoDebugModeGC dmgc(cx->runtime);
    return comp->setDebugModeFromC(cx, !!debug, dmgc);
}

static JSBool
CheckDebugMode(JSContext *cx)
{
    JSBool debugMode = JS_GetDebugMode(cx);
    /*
     * :TODO:
     * This probably should be an assertion, since it's indicative of a severe
     * API misuse.
     */
    if (!debugMode) {
        JS_ReportErrorFlagsAndNumber(cx, JSREPORT_ERROR, js_GetErrorMessage,
                                     NULL, JSMSG_NEED_DEBUG_MODE);
    }
    return debugMode;
}

JS_PUBLIC_API(JSBool)
JS_SetSingleStepMode(JSContext *cx, JSScript *script, JSBool singleStep)
{
    assertSameCompartment(cx, script);
    if (!CheckDebugMode(cx))
        return JS_FALSE;

    return script->setStepModeFlag(cx, singleStep);
}

JS_PUBLIC_API(JSBool)
JS_SetTrap(JSContext *cx, JSScript *script, jsbytecode *pc, JSTrapHandler handler, jsval closure)
{
    assertSameCompartment(cx, script, closure);

    if (!CheckDebugMode(cx))
        return false;

    BreakpointSite *site = script->getOrCreateBreakpointSite(cx, pc);
    if (!site)
        return false;
    site->setTrap(cx->runtime->defaultFreeOp(), handler, closure);
    return true;
}

JS_PUBLIC_API(void)
JS_ClearTrap(JSContext *cx, JSScript *script, jsbytecode *pc,
             JSTrapHandler *handlerp, jsval *closurep)
{
    if (BreakpointSite *site = script->getBreakpointSite(pc)) {
        site->clearTrap(cx->runtime->defaultFreeOp(), handlerp, closurep);
    } else {
        if (handlerp)
            *handlerp = NULL;
        if (closurep)
            *closurep = JSVAL_VOID;
    }
}

JS_PUBLIC_API(void)
JS_ClearScriptTraps(JSContext *cx, JSScript *script)
{
    script->clearTraps(cx->runtime->defaultFreeOp());
}

JS_PUBLIC_API(void)
JS_ClearAllTrapsForCompartment(JSContext *cx)
{
    cx->compartment->clearTraps(cx->runtime->defaultFreeOp());
}

JS_PUBLIC_API(JSBool)
JS_SetInterrupt(JSRuntime *rt, JSInterruptHook hook, void *closure)
{
    rt->debugHooks.interruptHook = hook;
    rt->debugHooks.interruptHookData = closure;
    for (InterpreterFrames *f = rt->interpreterFrames; f; f = f->older)
        f->enableInterruptsUnconditionally();
    return true;
}

JS_PUBLIC_API(JSBool)
JS_ClearInterrupt(JSRuntime *rt, JSInterruptHook *hoop, void **closurep)
{
    if (hoop)
        *hoop = rt->debugHooks.interruptHook;
    if (closurep)
        *closurep = rt->debugHooks.interruptHookData;
    rt->debugHooks.interruptHook = 0;
    rt->debugHooks.interruptHookData = 0;
    return JS_TRUE;
}

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

JS_PUBLIC_API(JSBool)
JS_SetWatchPoint(JSContext *cx, JSObject *obj_, jsid id,
                 JSWatchPointHandler handler, JSObject *closure_)
{
    assertSameCompartment(cx, obj_);

    RootedObject obj(cx, obj_), closure(cx, closure_);

    JSObject *origobj = obj;
    obj = GetInnerObject(cx, obj);
    if (!obj)
        return false;

    RootedValue v(cx);
    unsigned attrs;

    RootedId propid(cx);

    if (JSID_IS_INT(id)) {
        propid = id;
    } else if (JSID_IS_OBJECT(id)) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_CANT_WATCH_PROP);
        return false;
    } else {
        if (!ValueToId(cx, IdToValue(id), propid.address()))
            return false;
    }

    /*
     * If, by unwrapping and innerizing, we changed the object, check
     * again to make sure that we're allowed to set a watch point.
     */
    if (origobj != obj && !CheckAccess(cx, obj, propid, JSACC_WATCH, &v, &attrs))
        return false;

    if (!obj->isNative()) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_CANT_WATCH,
                             obj->getClass()->name);
        return false;
    }

    types::MarkTypePropertyConfigured(cx, obj, propid);

    WatchpointMap *wpmap = cx->compartment->watchpointMap;
    if (!wpmap) {
        wpmap = cx->runtime->new_<WatchpointMap>();
        if (!wpmap || !wpmap->init()) {
            js_ReportOutOfMemory(cx);
            return false;
        }
        cx->compartment->watchpointMap = wpmap;
    }
    return wpmap->watch(cx, obj, propid, handler, closure);
}

JS_PUBLIC_API(JSBool)
JS_ClearWatchPoint(JSContext *cx, JSObject *obj, jsid id,
                   JSWatchPointHandler *handlerp, JSObject **closurep)
{
    assertSameCompartment(cx, obj, id);

    if (WatchpointMap *wpmap = cx->compartment->watchpointMap)
        wpmap->unwatch(obj, id, handlerp, closurep);
    return true;
}

JS_PUBLIC_API(JSBool)
JS_ClearWatchPointsForObject(JSContext *cx, JSObject *obj)
{
    assertSameCompartment(cx, obj);

    if (WatchpointMap *wpmap = cx->compartment->watchpointMap)
        wpmap->unwatchObject(obj);
    return true;
}

JS_PUBLIC_API(JSBool)
JS_ClearAllWatchPoints(JSContext *cx)
{
    if (JSCompartment *comp = cx->compartment) {
        if (WatchpointMap *wpmap = comp->watchpointMap)
            wpmap->clear();
    }
    return true;
}

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

JS_PUBLIC_API(unsigned)
JS_PCToLineNumber(JSContext *cx, RawScript script, jsbytecode *pc)
{
    return js::PCToLineNumber(script, pc);
}

JS_PUBLIC_API(jsbytecode *)
JS_LineNumberToPC(JSContext *cx, JSScript *script, unsigned lineno)
{
    return js_LineNumberToPC(script, lineno);
}

JS_PUBLIC_API(jsbytecode *)
JS_EndPC(JSContext *cx, JSScript *script)
{
    return script->code + script->length;
}

JS_PUBLIC_API(JSBool)
JS_GetLinePCs(JSContext *cx, JSScript *script,
              unsigned startLine, unsigned maxLines,
              unsigned* count, unsigned** retLines, jsbytecode*** retPCs)
{
    size_t len = (script->length > maxLines ? maxLines : script->length);
    unsigned *lines = cx->pod_malloc<unsigned>(len);
    if (!lines)
        return JS_FALSE;

    jsbytecode **pcs = cx->pod_malloc<jsbytecode*>(len);
    if (!pcs) {
        js_free(lines);
        return JS_FALSE;
    }

    unsigned lineno = script->lineno;
    unsigned offset = 0;
    unsigned i = 0;
    for (jssrcnote *sn = script->notes(); !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn)) {
        offset += SN_DELTA(sn);
        SrcNoteType type = (SrcNoteType) SN_TYPE(sn);
        if (type == SRC_SETLINE || type == SRC_NEWLINE) {
            if (type == SRC_SETLINE)
                lineno = (unsigned) js_GetSrcNoteOffset(sn, 0);
            else
                lineno++;

            if (lineno >= startLine) {
                lines[i] = lineno;
                pcs[i] = script->code + offset;
                if (++i >= maxLines)
                    break;
            }
        }
    }

    *count = i;
    if (retLines)
        *retLines = lines;
    else
        js_free(lines);

    if (retPCs)
        *retPCs = pcs;
    else
        js_free(pcs);

    return JS_TRUE;
}

JS_PUBLIC_API(unsigned)
JS_GetFunctionArgumentCount(JSContext *cx, JSFunction *fun)
{
    return fun->nargs;
}

JS_PUBLIC_API(JSBool)
JS_FunctionHasLocalNames(JSContext *cx, JSFunction *fun)
{
    return fun->nonLazyScript()->bindings.count() > 0;
}

extern JS_PUBLIC_API(uintptr_t *)
JS_GetFunctionLocalNameArray(JSContext *cx, JSFunction *fun, void **markp)
{
    RootedScript script(cx, fun->nonLazyScript());
    BindingVector bindings(cx);
    if (!FillBindingVector(script, &bindings))
        return NULL;

    /* Munge data into the API this method implements.  Avert your eyes! */
    *markp = cx->tempLifoAlloc().mark();

    uintptr_t *names = cx->tempLifoAlloc().newArray<uintptr_t>(bindings.length());
    if (!names) {
        js_ReportOutOfMemory(cx);
        return NULL;
    }

    for (size_t i = 0; i < bindings.length(); i++)
        names[i] = reinterpret_cast<uintptr_t>(bindings[i].name());

    return names;
}

extern JS_PUBLIC_API(JSAtom *)
JS_LocalNameToAtom(uintptr_t w)
{
    return reinterpret_cast<JSAtom *>(w);
}

extern JS_PUBLIC_API(JSString *)
JS_AtomKey(JSAtom *atom)
{
    return atom;
}

extern JS_PUBLIC_API(void)
JS_ReleaseFunctionLocalNameArray(JSContext *cx, void *mark)
{
    cx->tempLifoAlloc().release(mark);
}

JS_PUBLIC_API(JSScript *)
JS_GetFunctionScript(JSContext *cx, JSFunction *fun)
{
    if (fun->isNative())
        return NULL;
    RawScript script;
    if (fun->isInterpretedLazy()) {
       AutoCompartment funCompartment(cx, fun);
       script = fun->getOrCreateScript(cx);
        if (!script)
            MOZ_CRASH();
    } else {
        script = fun->nonLazyScript();
    }
    return script;
}

JS_PUBLIC_API(JSNative)
JS_GetFunctionNative(JSContext *cx, JSFunction *fun)
{
    return fun->maybeNative();
}

JS_PUBLIC_API(JSPrincipals *)
JS_GetScriptPrincipals(JSScript *script)
{
    return script->principals;
}

JS_PUBLIC_API(JSPrincipals *)
JS_GetScriptOriginPrincipals(JSScript *script)
{
    return script->originPrincipals;
}

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

JS_PUBLIC_API(JSStackFrame *)
JS_BrokenFrameIterator(JSContext *cx, JSStackFrame **iteratorp)
{
    StackFrame *fp = Valueify(*iteratorp);
    if (!fp) {
#ifdef JS_METHODJIT
        js::mjit::ExpandInlineFrames(cx->compartment);
#endif
        fp = cx->maybefp();
    } else {
        fp = fp->prev();
    }

    // settle on the next non-ion frame as it is not considered safe to inspect
    // Ion's activation StackFrame.
    while (fp && fp->runningInIon())
        fp = fp->prev();

    *iteratorp = Jsvalify(fp);
    return *iteratorp;
}

JS_PUBLIC_API(JSScript *)
JS_GetFrameScript(JSContext *cx, JSStackFrame *fpArg)
{
    return Valueify(fpArg)->script();
}

JS_PUBLIC_API(jsbytecode *)
JS_GetFramePC(JSContext *cx, JSStackFrame *fpArg)
{
    /*
     * This API is used to compute the line number for jsd and XPConnect
     * exception handling backtraces. Once the stack gets really deep, the
     * overall cost can become quadratic. This can hang the browser (eventually
     * terminated by a slow-script dialog) when content causes infinite
     * recursion and a backtrace.
     */
    return Valueify(fpArg)->pcQuadratic(cx->stack, 100);
}

JS_PUBLIC_API(void *)
JS_GetFrameAnnotation(JSContext *cx, JSStackFrame *fpArg)
{
    StackFrame *fp = Valueify(fpArg);
    if (fp->annotation() && fp->scopeChain()->compartment()->principals) {
        /*
         * Give out an annotation only if privileges have not been revoked
         * or disabled globally.
         */
        return fp->annotation();
    }

    return NULL;
}

JS_PUBLIC_API(void)
JS_SetTopFrameAnnotation(JSContext *cx, void *annotation)
{
    AutoAssertNoGC nogc;
    StackFrame *fp = cx->fp();
    JS_ASSERT_IF(fp->beginsIonActivation(), !fp->annotation());

    // Note that if this frame is running in Ion, the actual calling frame
    // could be inlined or a callee and thus we won't have a correct |fp|.
    // To account for this, ion::InvalidationBailout will transfer an
    // annotation from the old cx->fp() to the new top frame. This works
    // because we will never EnterIon on a frame with an annotation.
    fp->setAnnotation(annotation);

    UnrootedScript script = fp->script();

    ReleaseAllJITCode(cx->runtime->defaultFreeOp());

    // Ensure that we'll never try to compile this again.
    JS_ASSERT(!script->hasAnyIonScript());
    script->ion = ION_DISABLED_SCRIPT;
    script->parallelIon = ION_DISABLED_SCRIPT;
}

JS_PUBLIC_API(JSObject *)
JS_GetFrameScopeChain(JSContext *cx, JSStackFrame *fpArg)
{
    StackFrame *fp = Valueify(fpArg);
    JS_ASSERT(cx->stack.space().containsSlow(fp));
    AutoCompartment ac(cx, fp->scopeChain());
    return GetDebugScopeForFrame(cx, fp);
}

JS_PUBLIC_API(JSObject *)
JS_GetFrameCallObject(JSContext *cx, JSStackFrame *fpArg)
{
    StackFrame *fp = Valueify(fpArg);
    JS_ASSERT(cx->stack.space().containsSlow(fp));

    if (!fp->isFunctionFrame())
        return NULL;

    JSObject *o = GetDebugScopeForFrame(cx, fp);

    /*
     * Given that fp is a function frame and GetDebugScopeForFrame always fills
     * in missing scopes, we can expect to find fp's CallObject on 'o'. Note:
     *  - GetDebugScopeForFrame wraps every ScopeObject (missing or not) with
     *    a DebugScopeObject proxy.
     *  - If fp is an eval-in-function, then fp has no callobj of its own and
     *    JS_GetFrameCallObject will return the innermost function's callobj.
     */
    while (o) {
        ScopeObject &scope = o->asDebugScope().scope();
        if (scope.isCall())
            return o;
        o = o->enclosingScope();
    }
    return NULL;
}

JS_PUBLIC_API(JSBool)
JS_GetFrameThis(JSContext *cx, JSStackFrame *fpArg, jsval *thisv)
{
    StackFrame *fp = Valueify(fpArg);

    js::AutoCompartment ac(cx, fp->scopeChain());
    if (!ComputeThis(cx, fp))
        return false;

    *thisv = fp->thisValue();
    return true;
}

JS_PUBLIC_API(JSFunction *)
JS_GetFrameFunction(JSContext *cx, JSStackFrame *fp)
{
    return Valueify(fp)->maybeScriptFunction();
}

JS_PUBLIC_API(JSObject *)
JS_GetFrameFunctionObject(JSContext *cx, JSStackFrame *fpArg)
{
    StackFrame *fp = Valueify(fpArg);
    if (!fp->isFunctionFrame())
        return NULL;

    JS_ASSERT(fp->callee().isFunction());
    return &fp->callee();
}

JS_PUBLIC_API(JSFunction *)
JS_GetScriptFunction(JSContext *cx, JSScript *script)
{
    return script->function();
}

JS_PUBLIC_API(JSObject *)
JS_GetParentOrScopeChain(JSContext *cx, JSObject *obj)
{
    return obj->enclosingScope();
}

JS_PUBLIC_API(JSBool)
JS_IsConstructorFrame(JSContext *cx, JSStackFrame *fp)
{
    return Valueify(fp)->isConstructing();
}

JS_PUBLIC_API(JSObject *)
JS_GetFrameCalleeObject(JSContext *cx, JSStackFrame *fp)
{
    return Valueify(fp)->maybeCalleev().toObjectOrNull();
}

JS_PUBLIC_API(const char *)
JS_GetDebugClassName(JSObject *obj)
{
    if (obj->isDebugScope())
        return obj->asDebugScope().scope().getClass()->name;
    return obj->getClass()->name;
}

JS_PUBLIC_API(JSBool)
JS_IsDebuggerFrame(JSContext *cx, JSStackFrame *fp)
{
    return Valueify(fp)->isDebuggerFrame();
}

JS_PUBLIC_API(JSBool)
JS_IsGlobalFrame(JSContext *cx, JSStackFrame *fp)
{
    return Valueify(fp)->isGlobalFrame();
}

JS_PUBLIC_API(jsval)
JS_GetFrameReturnValue(JSContext *cx, JSStackFrame *fp)
{
    return Valueify(fp)->returnValue();
}

JS_PUBLIC_API(void)
JS_SetFrameReturnValue(JSContext *cx, JSStackFrame *fpArg, jsval rval)
{
    AutoAssertNoGC nogc;
    StackFrame *fp = Valueify(fpArg);
#ifdef JS_METHODJIT
    JS_ASSERT(fp->script()->debugMode);
#endif
    assertSameCompartment(cx, fp, rval);
    fp->setReturnValue(rval);
}

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

JS_PUBLIC_API(const char *)
JS_GetScriptFilename(JSContext *cx, JSScript *script)
{
    return script->filename;
}

JS_PUBLIC_API(const jschar *)
JS_GetScriptSourceMap(JSContext *cx, JSScript *script)
{
    ScriptSource *source = script->scriptSource();
    JS_ASSERT(source);
    return source->hasSourceMap() ? source->sourceMap() : NULL;
}

JS_PUBLIC_API(unsigned)
JS_GetScriptBaseLineNumber(JSContext *cx, JSScript *script)
{
    return script->lineno;
}

JS_PUBLIC_API(unsigned)
JS_GetScriptLineExtent(JSContext *cx, JSScript *script)
{
    return js_GetScriptLineExtent(script);
}

JS_PUBLIC_API(JSVersion)
JS_GetScriptVersion(JSContext *cx, JSScript *script)
{
    return VersionNumber(script->getVersion());
}

JS_PUBLIC_API(bool)
JS_GetScriptUserBit(JSScript *script)
{
    return script->userBit;
}

JS_PUBLIC_API(void)
JS_SetScriptUserBit(JSScript *script, bool b)
{
    script->userBit = b;
}

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

JS_PUBLIC_API(void)
JS_SetNewScriptHook(JSRuntime *rt, JSNewScriptHook hook, void *callerdata)
{
    rt->debugHooks.newScriptHook = hook;
    rt->debugHooks.newScriptHookData = callerdata;
}

JS_PUBLIC_API(void)
JS_SetDestroyScriptHook(JSRuntime *rt, JSDestroyScriptHook hook,
                        void *callerdata)
{
    rt->debugHooks.destroyScriptHook = hook;
    rt->debugHooks.destroyScriptHookData = callerdata;
}

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

JS_PUBLIC_API(JSBool)
JS_EvaluateUCInStackFrame(JSContext *cx, JSStackFrame *fpArg,
                          const jschar *chars, unsigned length,
                          const char *filename, unsigned lineno,
                          jsval *rval)
{
    if (!CheckDebugMode(cx))
        return false;

    Rooted<Env*> env(cx, JS_GetFrameScopeChain(cx, fpArg));
    if (!env)
        return false;

    StackFrame *fp = Valueify(fpArg);

    if (!ComputeThis(cx, fp))
        return false;
    RootedValue thisv(cx, fp->thisValue());

    js::AutoCompartment ac(cx, env);
    return EvaluateInEnv(cx, env, thisv, fp, StableCharPtr(chars, length), length,
                         filename, lineno, rval);
}

JS_PUBLIC_API(JSBool)
JS_EvaluateInStackFrame(JSContext *cx, JSStackFrame *fp,
                        const char *bytes, unsigned length,
                        const char *filename, unsigned lineno,
                        jsval *rval)
{
    jschar *chars;
    JSBool ok;
    size_t len = length;

    if (!CheckDebugMode(cx))
        return JS_FALSE;

    chars = InflateString(cx, bytes, &len);
    if (!chars)
        return JS_FALSE;
    length = (unsigned) len;
    ok = JS_EvaluateUCInStackFrame(cx, fp, chars, length, filename, lineno,
                                   rval);
    js_free(chars);

    return ok;
}

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

/* This all should be reworked to avoid requiring JSScopeProperty types. */

static JSBool
GetPropertyDesc(JSContext *cx, JSObject *obj_, HandleShape shape, JSPropertyDesc *pd)
{
    assertSameCompartment(cx, obj_);
    pd->id = IdToJsval(shape->propid());

    RootedObject obj(cx, obj_);

    JSBool wasThrowing = cx->isExceptionPending();
    Value lastException = UndefinedValue();
    if (wasThrowing)
        lastException = cx->getPendingException();
    cx->clearPendingException();

    Rooted<jsid> id(cx, shape->propid());
    RootedValue value(cx);
    if (!baseops::GetProperty(cx, obj, id, &value)) {
        if (!cx->isExceptionPending()) {
            pd->flags = JSPD_ERROR;
            pd->value = JSVAL_VOID;
        } else {
            pd->flags = JSPD_EXCEPTION;
            pd->value = cx->getPendingException();
        }
    } else {
        pd->flags = 0;
        pd->value = value;
    }

    if (wasThrowing)
        cx->setPendingException(lastException);

    pd->flags |= (shape->enumerable() ? JSPD_ENUMERATE : 0)
              |  (!shape->writable()  ? JSPD_READONLY  : 0)
              |  (!shape->configurable() ? JSPD_PERMANENT : 0);
    pd->spare = 0;
    pd->alias = JSVAL_VOID;

    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_GetPropertyDescArray(JSContext *cx, JSObject *obj_, JSPropertyDescArray *pda)
{
    RootedObject obj(cx, obj_);

    assertSameCompartment(cx, obj);
    uint32_t i = 0;
    JSPropertyDesc *pd = NULL;

    if (obj->isDebugScope()) {
        AutoIdVector props(cx);
        if (!Proxy::enumerate(cx, obj, props))
            return false;

        pd = cx->pod_calloc<JSPropertyDesc>(props.length());
        if (!pd)
            return false;

        for (i = 0; i < props.length(); ++i) {
            pd[i].id = JSVAL_NULL;
            pd[i].value = JSVAL_NULL;
            if (!js_AddRoot(cx, &pd[i].id, NULL))
                goto bad;
            pd[i].id = IdToValue(props[i]);
            if (!js_AddRoot(cx, &pd[i].value, NULL))
                goto bad;
            if (!Proxy::get(cx, obj, obj, props.handleAt(i), MutableHandleValue::fromMarkedLocation(&pd[i].value)))
                goto bad;
        }

        pda->length = props.length();
        pda->array = pd;
        return true;
    }

    Class *clasp;
    clasp = obj->getClass();
    if (!obj->isNative() || (clasp->flags & JSCLASS_NEW_ENUMERATE)) {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                             JSMSG_CANT_DESCRIBE_PROPS, clasp->name);
        return false;
    }
    if (!clasp->enumerate(cx, obj))
        return false;

    /* Return an empty pda early if obj has no own properties. */
    if (obj->nativeEmpty()) {
        pda->length = 0;
        pda->array = NULL;
        return true;
    }

    pd = cx->pod_malloc<JSPropertyDesc>(obj->propertyCount());
    if (!pd)
        return false;
    for (Shape::Range r = obj->lastProperty()->all(); !r.empty(); r.popFront()) {
        pd[i].id = JSVAL_NULL;
        pd[i].value = JSVAL_NULL;
        pd[i].alias = JSVAL_NULL;
        if (!js_AddRoot(cx, &pd[i].id, NULL))
            goto bad;
        if (!js_AddRoot(cx, &pd[i].value, NULL))
            goto bad;
        RootedShape shape(cx, const_cast<Shape *>(&r.front()));
        if (!GetPropertyDesc(cx, obj, shape, &pd[i]))
            goto bad;
        if ((pd[i].flags & JSPD_ALIAS) && !js_AddRoot(cx, &pd[i].alias, NULL))
            goto bad;
        if (++i == obj->propertyCount())
            break;
    }
    pda->length = i;
    pda->array = pd;
    return true;

bad:
    pda->length = i + 1;
    pda->array = pd;
    JS_PutPropertyDescArray(cx, pda);
    return false;
}

JS_PUBLIC_API(void)
JS_PutPropertyDescArray(JSContext *cx, JSPropertyDescArray *pda)
{
    JSPropertyDesc *pd;
    uint32_t i;

    pd = pda->array;
    for (i = 0; i < pda->length; i++) {
        js_RemoveRoot(cx->runtime, &pd[i].id);
        js_RemoveRoot(cx->runtime, &pd[i].value);
        if (pd[i].flags & JSPD_ALIAS)
            js_RemoveRoot(cx->runtime, &pd[i].alias);
    }
    js_free(pd);
    pda->array = NULL;
    pda->length = 0;
}

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

JS_PUBLIC_API(JSBool)
JS_SetDebuggerHandler(JSRuntime *rt, JSDebuggerHandler handler, void *closure)
{
    rt->debugHooks.debuggerHandler = handler;
    rt->debugHooks.debuggerHandlerData = closure;
    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_SetSourceHandler(JSRuntime *rt, JSSourceHandler handler, void *closure)
{
    rt->debugHooks.sourceHandler = handler;
    rt->debugHooks.sourceHandlerData = closure;
    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_SetExecuteHook(JSRuntime *rt, JSInterpreterHook hook, void *closure)
{
    rt->debugHooks.executeHook = hook;
    rt->debugHooks.executeHookData = closure;
    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_SetCallHook(JSRuntime *rt, JSInterpreterHook hook, void *closure)
{
    rt->debugHooks.callHook = hook;
    rt->debugHooks.callHookData = closure;
    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_SetThrowHook(JSRuntime *rt, JSThrowHook hook, void *closure)
{
    rt->debugHooks.throwHook = hook;
    rt->debugHooks.throwHookData = closure;
    return JS_TRUE;
}

JS_PUBLIC_API(JSBool)
JS_SetDebugErrorHook(JSRuntime *rt, JSDebugErrorHook hook, void *closure)
{
    rt->debugHooks.debugErrorHook = hook;
    rt->debugHooks.debugErrorHookData = closure;
    return JS_TRUE;
}

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

JS_PUBLIC_API(size_t)
JS_GetObjectTotalSize(JSContext *cx, JSObject *obj)
{
    return obj->computedSizeOfThisSlotsElements();
}

static size_t
GetAtomTotalSize(JSContext *cx, JSAtom *atom)
{
    return sizeof(AtomStateEntry) + sizeof(HashNumber) +
           sizeof(JSString) +
           (atom->length() + 1) * sizeof(jschar);
}

JS_PUBLIC_API(size_t)
JS_GetFunctionTotalSize(JSContext *cx, JSFunction *fun)
{
    AutoAssertNoGC nogc;
    size_t nbytes = sizeof *fun;
    nbytes += JS_GetObjectTotalSize(cx, fun);
    if (fun->isInterpreted())
        nbytes += JS_GetScriptTotalSize(cx, fun->nonLazyScript());
    if (fun->displayAtom())
        nbytes += GetAtomTotalSize(cx, fun->displayAtom());
    return nbytes;
}

JS_PUBLIC_API(size_t)
JS_GetScriptTotalSize(JSContext *cx, JSScript *script)
{
    size_t nbytes, pbytes;
    jssrcnote *sn, *notes;
    ObjectArray *objarray;
    JSPrincipals *principals;

    nbytes = sizeof *script;
    nbytes += script->length * sizeof script->code[0];
    nbytes += script->natoms * sizeof script->atoms[0];
    for (size_t i = 0; i < script->natoms; i++)
        nbytes += GetAtomTotalSize(cx, script->atoms[i]);

    if (script->filename)
        nbytes += strlen(script->filename) + 1;

    notes = script->notes();
    for (sn = notes; !SN_IS_TERMINATOR(sn); sn = SN_NEXT(sn))
        continue;
    nbytes += (sn - notes + 1) * sizeof *sn;

    if (script->hasObjects()) {
        objarray = script->objects();
        size_t i = objarray->length;
        nbytes += sizeof *objarray + i * sizeof objarray->vector[0];
        do {
            nbytes += JS_GetObjectTotalSize(cx, objarray->vector[--i]);
        } while (i != 0);
    }

    if (script->hasRegexps()) {
        objarray = script->regexps();
        size_t i = objarray->length;
        nbytes += sizeof *objarray + i * sizeof objarray->vector[0];
        do {
            nbytes += JS_GetObjectTotalSize(cx, objarray->vector[--i]);
        } while (i != 0);
    }

    if (script->hasTrynotes())
        nbytes += sizeof(TryNoteArray) + script->trynotes()->length * sizeof(JSTryNote);

    principals = script->principals;
    if (principals) {
        JS_ASSERT(principals->refcount);
        pbytes = sizeof *principals;
        if (principals->refcount > 1)
            pbytes = JS_HOWMANY(pbytes, principals->refcount);
        nbytes += pbytes;
    }

    return nbytes;
}

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

JS_FRIEND_API(void)
js_RevertVersion(JSContext *cx)
{
    cx->clearVersionOverride();
}

JS_PUBLIC_API(const JSDebugHooks *)
JS_GetGlobalDebugHooks(JSRuntime *rt)
{
    return &rt->debugHooks;
}

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

JS_PUBLIC_API(void)
JS_DumpBytecode(JSContext *cx, JSScript *scriptArg)
{
#if defined(DEBUG)
    Rooted<JSScript*> script(cx, scriptArg);

    Sprinter sprinter(cx);
    if (!sprinter.init())
        return;

    fprintf(stdout, "--- SCRIPT %s:%d ---\n", script->filename, script->lineno);
    js_Disassemble(cx, script, true, &sprinter);
    fputs(sprinter.string(), stdout);
    fprintf(stdout, "--- END SCRIPT %s:%d ---\n", script->filename, script->lineno);
#endif
}

extern JS_PUBLIC_API(void)
JS_DumpPCCounts(JSContext *cx, JSScript *scriptArg)
{
#if defined(DEBUG)
    Rooted<JSScript*> script(cx, scriptArg);
    JS_ASSERT(script->hasScriptCounts);

    Sprinter sprinter(cx);
    if (!sprinter.init())
        return;

    fprintf(stdout, "--- SCRIPT %s:%d ---\n", script->filename, script->lineno);
    js_DumpPCCounts(cx, script, &sprinter);
    fputs(sprinter.string(), stdout);
    fprintf(stdout, "--- END SCRIPT %s:%d ---\n", script->filename, script->lineno);
#endif
}

namespace {

typedef Vector<JSScript *, 0, SystemAllocPolicy> ScriptsToDump;

static void
DumpBytecodeScriptCallback(JSRuntime *rt, void *data, void *thing,
                           JSGCTraceKind traceKind, size_t thingSize)
{
    JS_ASSERT(traceKind == JSTRACE_SCRIPT);
    JSScript *script = static_cast<JSScript *>(thing);
    static_cast<ScriptsToDump *>(data)->append(script);
}

} /* anonymous namespace */

JS_PUBLIC_API(void)
JS_DumpCompartmentBytecode(JSContext *cx)
{
    ScriptsToDump scripts;
    IterateCells(cx->runtime, cx->compartment, gc::FINALIZE_SCRIPT, &scripts, DumpBytecodeScriptCallback);

    for (size_t i = 0; i < scripts.length(); i++) {
        if (scripts[i]->enclosingScriptsCompiledSuccessfully())
            JS_DumpBytecode(cx, scripts[i]);
    }
}

JS_PUBLIC_API(void)
JS_DumpCompartmentPCCounts(JSContext *cx)
{
    for (CellIter i(cx->compartment, gc::FINALIZE_SCRIPT); !i.done(); i.next()) {
        JSScript *script = i.get<JSScript>();
        if (script->hasScriptCounts && script->enclosingScriptsCompiledSuccessfully())
            JS_DumpPCCounts(cx, script);
    }
}

JS_PUBLIC_API(JSObject *)
JS_UnwrapObject(JSObject *obj)
{
    return UnwrapObject(obj);
}

JS_PUBLIC_API(JSObject *)
JS_UnwrapObjectAndInnerize(JSObject *obj)
{
    return UnwrapObject(obj, /* stopAtOuter = */ false);
}

JS_FRIEND_API(JSBool)
js_CallContextDebugHandler(JSContext *cx)
{
    AssertCanGC();
    ScriptFrameIter iter(cx);
    JS_ASSERT(!iter.done());

    RootedValue rval(cx);
    RootedScript script(cx, iter.script());
    switch (js::CallContextDebugHandler(cx, script, iter.pc(), rval.address())) {
      case JSTRAP_ERROR:
        JS_ClearPendingException(cx);
        return JS_FALSE;
      case JSTRAP_THROW:
        JS_SetPendingException(cx, rval);
        return JS_FALSE;
      case JSTRAP_RETURN:
      case JSTRAP_CONTINUE:
      default:
        return JS_TRUE;
    }
}

JS_PUBLIC_API(StackDescription *)
JS::DescribeStack(JSContext *cx, unsigned maxFrames)
{
    AutoAssertNoGC nogc;
    Vector<FrameDescription> frames(cx);

    for (ScriptFrameIter i(cx); !i.done(); ++i) {
        FrameDescription desc;
        desc.script = i.script();
        desc.lineno = PCToLineNumber(i.script(), i.pc());
        desc.fun = i.maybeCallee();
        if (!frames.append(desc))
            return NULL;
        if (frames.length() == maxFrames)
            break;
    }

    StackDescription *desc = js_new<StackDescription>();
    if (!desc)
        return NULL;

    desc->nframes = frames.length();
    desc->frames = frames.extractRawBuffer();
    return desc;
}

JS_PUBLIC_API(void)
JS::FreeStackDescription(JSContext *cx, StackDescription *desc)
{
    js_delete(desc->frames);
    js_delete(desc);
}

class AutoPropertyDescArray
{
    JSContext *cx_;
    JSPropertyDescArray descArray_;

  public:
    AutoPropertyDescArray(JSContext *cx)
      : cx_(cx)
    {
        PodZero(&descArray_);
    }
    ~AutoPropertyDescArray()
    {
        if (descArray_.array)
            JS_PutPropertyDescArray(cx_, &descArray_);
    }

    void fetch(JSObject *obj) {
        JS_ASSERT(!descArray_.array);
        if (!JS_GetPropertyDescArray(cx_, obj, &descArray_))
            descArray_.array = NULL;
    }

    JSPropertyDescArray * operator ->() {
        return &descArray_;
    }
};

static const char *
FormatValue(JSContext *cx, const Value &v, JSAutoByteString &bytes)
{
    JSString *str = ToString(cx, v);
    if (!str)
        return NULL;
    const char *buf = bytes.encode(cx, str);
    if (!buf)
        return NULL;
    const char *found = strstr(buf, "function ");
    if (found && (found - buf <= 2))
        return "[function]";
    return buf;
}

static char *
FormatFrame(JSContext *cx, const ScriptFrameIter &iter, char *buf, int num,
            JSBool showArgs, JSBool showLocals, JSBool showThisProps)
{
    AssertCanGC();

    RootedScript script(cx, iter.script());
    jsbytecode* pc = iter.pc();

    RootedObject scopeChain(cx, iter.scopeChain());
    JSAutoCompartment ac(cx, scopeChain);

    const char *filename = script->filename;
    unsigned lineno = PCToLineNumber(script, pc);
    RootedFunction fun(cx, iter.maybeCallee());
    RootedString funname(cx);
    if (fun)
        funname = fun->atom();

    RootedObject callObj(cx);
    AutoPropertyDescArray callProps(cx);

    if (!iter.isIon() && (showArgs || showLocals)) {
        callObj = JS_GetFrameCallObject(cx, Jsvalify(iter.interpFrame()));
        if (callObj)
            callProps.fetch(callObj);
    }

    RootedValue thisVal(cx);
    AutoPropertyDescArray thisProps(cx);
    if (iter.computeThis()) {
        thisVal = iter.thisv();
        if (showThisProps && !thisVal.isPrimitive())
            thisProps.fetch(&thisVal.toObject());
    }

    // print the frame number and function name
    if (funname) {
        JSAutoByteString funbytes;
        buf = JS_sprintf_append(buf, "%d %s(", num, funbytes.encode(cx, funname));
    } else if (fun) {
        buf = JS_sprintf_append(buf, "%d anonymous(", num);
    } else {
        buf = JS_sprintf_append(buf, "%d <TOP LEVEL>", num);
    }
    if (!buf)
        return buf;

    // print the function arguments
    if (showArgs && callObj) {
        uint32_t namedArgCount = 0;
        for (uint32_t i = 0; i < callProps->length; i++) {
            JSPropertyDesc* desc = &callProps->array[i];
            JSAutoByteString nameBytes;
            const char *name = NULL;
            if (JSVAL_IS_STRING(desc->id))
                name = FormatValue(cx, desc->id, nameBytes);

            JSAutoByteString valueBytes;
            const char *value = FormatValue(cx, desc->value, valueBytes);

            buf = JS_sprintf_append(buf, "%s%s%s%s%s%s",
                                    namedArgCount ? ", " : "",
                                    name ? name :"",
                                    name ? " = " : "",
                                    desc->value.isString() ? "\"" : "",
                                    value ? value : "?unknown?",
                                    desc->value.isString() ? "\"" : "");
            if (!buf)
                return buf;
            namedArgCount++;
        }

        // print any unnamed trailing args (found in 'arguments' object)
        RootedValue val(cx);
        if (JS_GetProperty(cx, callObj, "arguments", val.address()) && val.isObject()) {
            uint32_t argCount;
            RootedObject argsObj(cx, &val.toObject());
            if (JS_GetProperty(cx, argsObj, "length", val.address()) &&
                ToUint32(cx, val, &argCount) &&
                argCount > namedArgCount)
            {
                for (uint32_t k = namedArgCount; k < argCount; k++) {
                    char number[8];
                    JS_snprintf(number, 8, "%d", (int) k);

                    if (JS_GetProperty(cx, argsObj, number, val.address())) {
                        JSAutoByteString valueBytes;
                        const char *value = FormatValue(cx, val, valueBytes);
                        buf = JS_sprintf_append(buf, "%s%s%s%s",
                                                k ? ", " : "",
                                                val.isString() ? "\"" : "",
                                                value ? value : "?unknown?",
                                                val.isString() ? "\"" : "");
                        if (!buf)
                            return buf;
                    }
                }
            }
        }
    }

    // print filename and line number
    buf = JS_sprintf_append(buf, "%s [\"%s\":%d]\n",
                            fun ? ")" : "",
                            filename ? filename : "<unknown>",
                            lineno);
    if (!buf)
        return buf;

    // print local variables
    if (showLocals && callProps->array) {
        for (uint32_t i = 0; i < callProps->length; i++) {
            JSPropertyDesc* desc = &callProps->array[i];
            JSAutoByteString nameBytes;
            JSAutoByteString valueBytes;
            const char *name = FormatValue(cx, desc->id, nameBytes);
            const char *value = FormatValue(cx, desc->value, valueBytes);

            if (name && value) {
                buf = JS_sprintf_append(buf, "    %s = %s%s%s\n",
                                        name,
                                        desc->value.isString() ? "\"" : "",
                                        value,
                                        desc->value.isString() ? "\"" : "");
                if (!buf)
                    return buf;
            }
        }
    }

    // print the value of 'this'
    if (showLocals) {
        if (!thisVal.isUndefined()) {
            JSAutoByteString thisValBytes;
            RootedString thisValStr(cx, ToString(cx, thisVal));
            if (thisValStr) {
                if (const char *str = thisValBytes.encode(cx, thisValStr)) {
                    buf = JS_sprintf_append(buf, "    this = %s\n", str);
                    if (!buf)
                        return buf;
                }
            }
        } else {
            buf = JS_sprintf_append(buf, "    <failed to get 'this' value>\n");
        }
    }

    // print the properties of 'this', if it is an object
    if (showThisProps && thisProps->array) {
        for (uint32_t i = 0; i < thisProps->length; i++) {
            JSPropertyDesc* desc = &thisProps->array[i];
            if (desc->flags & JSPD_ENUMERATE) {
                JSAutoByteString nameBytes;
                JSAutoByteString valueBytes;
                const char *name = FormatValue(cx, desc->id, nameBytes);
                const char *value = FormatValue(cx, desc->value, valueBytes);
                if (name && value) {
                    buf = JS_sprintf_append(buf, "    this.%s = %s%s%s\n",
                                            name,
                                            desc->value.isString() ? "\"" : "",
                                            value,
                                            desc->value.isString() ? "\"" : "");
                    if (!buf)
                        return buf;
                }
            }
        }
    }

    return buf;
}

JS_PUBLIC_API(char *)
JS::FormatStackDump(JSContext *cx, char *buf,
                      JSBool showArgs, JSBool showLocals,
                      JSBool showThisProps)
{
    int num = 0;

    for (ScriptFrameIter i(cx); !i.done(); ++i) {
        buf = FormatFrame(cx, i, buf, num, showArgs, showLocals, showThisProps);
        num++;
    }

    if (!num)
        buf = JS_sprintf_append(buf, "JavaScript stack is empty\n");

    return buf;
}