Remove JS_FrameIterator (bug 732653, r=luke,mrbkap).

caps/src/nsScriptSecurityManager.cpp

@@ -2257,8 +2257,8 @@ nsScriptSecurityManager::GetPrincipalAndFrame(JSContext *cx,
     if (cx)
     {
         // Get principals from innermost JavaScript frame.
-        JSStackFrame *fp = nullptr; // tell JS_FrameIterator to start at innermost
-        for (fp = JS_FrameIterator(cx, &fp); fp; fp = JS_FrameIterator(cx, &fp))
+        JSStackFrame *fp = nullptr; // tell JS_BrokenFrameIterator to start at innermost
+        for (fp = JS_BrokenFrameIterator(cx, &fp); fp; fp = JS_BrokenFrameIterator(cx, &fp))
         {
             nsIPrincipal* result = GetFramePrincipal(cx, fp, rv);
             if (result)
@@ -2286,7 +2286,7 @@ nsScriptSecurityManager::GetPrincipalAndFrame(JSContext *cx,
             if (result)
             {
                 JSStackFrame *inner = nullptr;
-                *frameResult = JS_FrameIterator(cx, &inner);
+                *frameResult = JS_BrokenFrameIterator(cx, &inner);
                 return result;
             }
         }
@@ -2451,7 +2451,7 @@ nsScriptSecurityManager::IsCapabilityEnabled(const char *capability,
     nsresult rv;
     JSStackFrame *fp = nullptr;
     JSContext *cx = GetCurrentJSContext();
-    fp = cx ? JS_FrameIterator(cx, &fp) : nullptr;
+    fp = cx ? JS_BrokenFrameIterator(cx, &fp) : nullptr;
 
     if (!fp)
     {
@@ -2502,7 +2502,7 @@ nsScriptSecurityManager::IsCapabilityEnabled(const char *capability,
         // the JS engine via JS_EvaluateScript or similar APIs.
         if (JS_IsGlobalFrame(cx, fp))
             break;
-    } while ((fp = JS_FrameIterator(cx, &fp)) != nullptr);
+    } while ((fp = JS_BrokenFrameIterator(cx, &fp)) != nullptr);
 
     if (!previousPrincipal)
     {

js/jsd/jsd_scpt.c

@@ -289,7 +289,7 @@ jsd_FindOrCreateJSDScript(JSDContext    *jsdc,
 
     /* Fallback for unknown scripts: create a new script. */
     if (!fp)
-        JS_FrameIterator(cx, &fp);
+        JS_BrokenFrameIterator(cx, &fp);
     if (fp)
         jsdscript = _newJSDScript(jsdc, cx, script);
 

js/jsd/jsd_stak.c

@@ -90,7 +90,7 @@ jsd_NewThreadState(JSDContext* jsdc, JSContext *cx )
     jsdthreadstate->stackDepth = 0;
 
     JS_BeginRequest(jsdthreadstate->context);
-    while( NULL != (fp = JS_FrameIterator(cx, &iter)) )
+    while( NULL != (fp = JS_BrokenFrameIterator(cx, &iter)) )
     {
         JSScript* script = JS_GetFrameScript(cx, fp);
         uintptr_t  pc = (uintptr_t) JS_GetFramePC(cx, fp);

js/src/jsdbgapi.cpp

@@ -479,11 +479,8 @@ JS_GetScriptOriginPrincipals(JSScript *script)
 
 /************************************************************************/
 
-/*
- *  Stack Frame Iterator
- */
 JS_PUBLIC_API(JSStackFrame *)
-JS_FrameIterator(JSContext *cx, JSStackFrame **iteratorp)
+JS_BrokenFrameIterator(JSContext *cx, JSStackFrame **iteratorp)
 {
     StackFrame *fp = Valueify(*iteratorp);
     *iteratorp = Jsvalify((fp == NULL) ? js_GetTopStackFrame(cx, FRAME_EXPAND_ALL) : fp->prev());
@@ -1843,3 +1840,267 @@ js_CallContextDebugHandler(JSContext *cx)
     }
 }
 
+JS_PUBLIC_API(StackDescription *)
+JS::DescribeStack(JSContext *cx, unsigned maxFrames)
+{
+    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.fp()->maybeFun();
+        if (!frames.append(desc))
+            return NULL;
+        if (frames.length() == maxFrames)
+            break;
+    }
+
+    StackDescription *desc = cx->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)
+{
+    cx->free_(desc->frames);
+    cx->free_(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)
+{
+    JSScript* script = iter.script();
+    jsbytecode* pc = iter.pc();
+
+    JSAutoEnterCompartment ac;
+    if (!ac.enter(cx, iter.fp()->scopeChain()))
+        return buf;
+
+    const char *filename = script->filename;
+    unsigned lineno = PCToLineNumber(script, pc);
+    JSFunction *fun = iter.fp()->maybeFun();
+    JSString *funname = NULL;
+    if (fun)
+        funname = fun->atom;
+
+    JSObject *callObj = NULL;
+    AutoPropertyDescArray callProps(cx);
+
+    if (showArgs || showLocals) {
+        callObj = JS_GetFrameCallObject(cx, Jsvalify(iter.fp()));
+        if (callObj)
+            callProps.fetch(callObj);
+    }
+
+    Value thisVal = UndefinedValue();
+    AutoPropertyDescArray thisProps(cx);
+    if (ComputeThis(cx, iter.fp())) {
+        thisVal = iter.fp()->thisValue();
+        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)
+        Value val;
+        if (JS_GetProperty(cx, callObj, "arguments", &val) && val.isObject()) {
+            uint32_t argCount;
+            JSObject* argsObj = &val.toObject();
+            if (JS_GetProperty(cx, argsObj, "length", &val) &&
+                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)) {
+                        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;
+            if (JSString* thisValStr = ToString(cx, thisVal)) {
+                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;
+}
+

js/src/jsdbgapi.h

@@ -50,6 +50,30 @@ class JS_PUBLIC_API(AutoEnterFrameCompartment) : public AutoEnterScriptCompartme
     bool enter(JSContext *cx, JSStackFrame *target);
 };
 
+struct FrameDescription
+{
+    JSScript *script;
+    unsigned lineno;
+    JSFunction *fun;
+};
+
+struct StackDescription
+{
+    unsigned nframes;
+    FrameDescription *frames;
+};
+
+extern JS_PUBLIC_API(StackDescription *)
+DescribeStack(JSContext *cx, unsigned maxFrames);
+
+extern JS_PUBLIC_API(void)
+FreeStackDescription(JSContext *cx, StackDescription *desc);
+
+extern JS_PUBLIC_API(char *)
+FormatStackDump(JSContext *cx, char *buf,
+                    JSBool showArgs, JSBool showLocals,
+                    JSBool showThisProps);
+
 } /* namespace JS */
 
 #ifdef DEBUG
@@ -200,14 +224,16 @@ extern JS_PUBLIC_API(JSPrincipals *)
 JS_GetScriptOriginPrincipals(JSScript *script);
 
 /*
- * Stack Frame Iterator
+ * This function does not work when IonMonkey is active. It remains for legacy
+ * code: caps/principal clamping, which will be removed shortly after
+ * compartment-per-global, and jsd, which can only be used when IonMonkey is
+ * disabled.
  *
- * Used to iterate through the JS stack frames to extract
- * information from the frames.
+ * To find the calling script and line number, use JS_DescribeSciptedCaller.
+ * To summarize the call stack, use JS::DescribeStack.
  */
-
 extern JS_PUBLIC_API(JSStackFrame *)
-JS_FrameIterator(JSContext *cx, JSStackFrame **iteratorp);
+JS_BrokenFrameIterator(JSContext *cx, JSStackFrame **iteratorp);
 
 extern JS_PUBLIC_API(JSScript *)
 JS_GetFrameScript(JSContext *cx, JSStackFrame *fp);

js/xpconnect/src/XPCDebug.cpp

@@ -10,11 +10,6 @@
 #include <windows.h>
 #endif
 
-#ifdef TAB
-#undef TAB
-#endif
-#define TAB "    "
-
 static void DebugDump(const char* fmt, ...)
 {
   char buffer[2048];
@@ -35,232 +30,6 @@ static void DebugDump(const char* fmt, ...)
   printf("%s", buffer);
 }
 
-static const char* JSVAL2String(JSContext* cx, jsval val, JSBool* isString,
-                                JSAutoByteString *bytes)
-{
-    JSAutoRequest ar(cx);
-    const char* value = nullptr;
-    JSString* value_str = JS_ValueToString(cx, val);
-    if (value_str)
-        value = bytes->encode(cx, value_str);
-    if (value) {
-        const char* found = strstr(value, "function ");
-        if (found && (value == found || value+1 == found || value+2 == found))
-            value = "[function]";
-    }
-
-    if (isString)
-        *isString = JSVAL_IS_STRING(val);
-    return value;
-}
-
-static char* FormatJSFrame(JSContext* cx, JSStackFrame* fp,
-                           char* buf, int num,
-                           JSBool showArgs, JSBool showLocals, JSBool showThisProps)
-{
-    JSPropertyDescArray callProps = {0, nullptr};
-    JSPropertyDescArray thisProps = {0, nullptr};
-    JSBool gotThisVal = false;
-    jsval thisVal;
-    JSObject* callObj = nullptr;
-    JSString* funname = nullptr;
-    JSAutoByteString funbytes;
-    const char* filename = nullptr;
-    PRInt32 lineno = 0;
-    JSFunction* fun = nullptr;
-    uint32_t namedArgCount = 0;
-    JSBool isString;
-
-    // get the info for this stack frame
-
-    JSScript* script = JS_GetFrameScript(cx, fp);
-    jsbytecode* pc = JS_GetFramePC(cx, fp);
-
-    JSAutoRequest ar(cx);
-    JSAutoEnterCompartment ac;
-    if (!ac.enter(cx, JS_GetGlobalForFrame(fp)))
-        return buf;
-
-    if (script && pc) {
-        filename = JS_GetScriptFilename(cx, script);
-        lineno =  (PRInt32) JS_PCToLineNumber(cx, script, pc);
-        fun = JS_GetFrameFunction(cx, fp);
-        if (fun)
-            funname = JS_GetFunctionId(fun);
-
-        if (showArgs || showLocals) {
-            callObj = JS_GetFrameCallObject(cx, fp);
-            if (callObj)
-                if (!JS_GetPropertyDescArray(cx, callObj, &callProps))
-                    callProps.array = nullptr;  // just to be sure
-        }
-
-        gotThisVal = JS_GetFrameThis(cx, fp, &thisVal);
-        if (!gotThisVal ||
-            !showThisProps ||
-            JSVAL_IS_PRIMITIVE(thisVal) ||
-            !JS_GetPropertyDescArray(cx, JSVAL_TO_OBJECT(thisVal),
-                                     &thisProps)) {
-            thisProps.array = nullptr;  // just to be sure
-        }
-    }
-
-    // print the frame number and function name
-
-    if (funname)
-        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) goto out;
-
-    // print the function arguments
-
-    if (showArgs && callObj) {
-        for (uint32_t i = 0; i < callProps.length; i++) {
-            JSPropertyDesc* desc = &callProps.array[i];
-            JSAutoByteString nameBytes;
-            const char* name = JSVAL2String(cx, desc->id, &isString, &nameBytes);
-            if (!isString)
-                name = nullptr;
-            JSAutoByteString valueBytes;
-            const char* value = JSVAL2String(cx, desc->value, &isString, &valueBytes);
-
-            buf = JS_sprintf_append(buf, "%s%s%s%s%s%s",
-                                    namedArgCount ? ", " : "",
-                                    name ? name :"",
-                                    name ? " = " : "",
-                                    isString ? "\"" : "",
-                                    value ? value : "?unknown?",
-                                    isString ? "\"" : "");
-            if (!buf) goto out;
-            namedArgCount++;
-        }
-
-        // print any unnamed trailing args (found in 'arguments' object)
-        JS::Value val;
-        if (JS_GetProperty(cx, callObj, "arguments", &val) &&
-            val.isObject()) {
-            uint32_t argCount;
-            JSObject* argsObj = &val.toObject();
-            if (JS_GetProperty(cx, argsObj, "length", &val) &&
-                JS_ValueToECMAUint32(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)) {
-                        JSAutoByteString valueBytes;
-                        const char *value = JSVAL2String(cx, val, &isString, &valueBytes);
-                        buf = JS_sprintf_append(buf, "%s%s%s%s",
-                                                k ? ", " : "",
-                                                isString ? "\"" : "",
-                                                value ? value : "?unknown?",
-                                                isString ? "\"" : "");
-                        if (!buf) goto out;
-                    }
-                }
-            }
-        }
-    }
-
-    // print filename and line number
-
-    buf = JS_sprintf_append(buf, "%s [\"%s\":%d]\n",
-                            fun ? ")" : "",
-                            filename ? filename : "<unknown>",
-                            lineno);
-    if (!buf) goto out;
-
-    // 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 = JSVAL2String(cx, desc->id, nullptr, &nameBytes);
-            const char *value = JSVAL2String(cx, desc->value, &isString, &valueBytes);
-
-            if (name && value) {
-                buf = JS_sprintf_append(buf, TAB "%s = %s%s%s\n",
-                                        name,
-                                        isString ? "\"" : "",
-                                        value,
-                                        isString ? "\"" : "");
-                if (!buf) goto out;
-            }
-        }
-    }
-
-    // print the value of 'this'
-
-    if (showLocals) {
-        if (gotThisVal) {
-            JSString* thisValStr;
-            JSAutoByteString thisValBytes;
-
-            if (nullptr != (thisValStr = JS_ValueToString(cx, thisVal)) &&
-                thisValBytes.encode(cx, thisValStr)) {
-                buf = JS_sprintf_append(buf, TAB "this = %s\n", thisValBytes.ptr());
-                if (!buf) goto out;
-            }
-        } else
-            buf = JS_sprintf_append(buf, TAB "<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 = JSVAL2String(cx, desc->id, nullptr, &nameBytes);
-                const char *value = JSVAL2String(cx, desc->value, &isString, &valueBytes);
-                if (name && value) {
-                    buf = JS_sprintf_append(buf, TAB "this.%s = %s%s%s\n",
-                                            name,
-                                            isString ? "\"" : "",
-                                            value,
-                                            isString ? "\"" : "");
-                    if (!buf) goto out;
-                }
-            }
-        }
-    }
-
-out:
-    if (callProps.array)
-        JS_PutPropertyDescArray(cx, &callProps);
-    if (thisProps.array)
-        JS_PutPropertyDescArray(cx, &thisProps);
-    return buf;
-}
-
-static char* FormatJSStackDump(JSContext* cx, char* buf,
-                               JSBool showArgs, JSBool showLocals,
-                               JSBool showThisProps)
-{
-    JSStackFrame* fp;
-    JSStackFrame* iter = nullptr;
-    int num = 0;
-
-    while (nullptr != (fp = JS_FrameIterator(cx, &iter))) {
-        buf = FormatJSFrame(cx, fp, buf, num, showArgs, showLocals, showThisProps);
-        num++;
-    }
-
-    if (!num)
-        buf = JS_sprintf_append(buf, "JavaScript stack is empty\n");
-
-    return buf;
-}
-
 JSBool
 xpc_DumpJSStack(JSContext* cx, JSBool showArgs, JSBool showLocals, JSBool showThisProps)
 {
@@ -282,7 +51,7 @@ xpc_PrintJSStack(JSContext* cx, JSBool showArgs, JSBool showLocals,
 
     JS_ClearPendingException(cx);
 
-    buf = FormatJSStackDump(cx, nullptr, showArgs, showLocals, showThisProps);
+    buf = JS::FormatStackDump(cx, nullptr, showArgs, showLocals, showThisProps);
     if (!buf)
         DebugDump("%s", "Failed to format JavaScript stack for dump\n");
 
@@ -313,7 +82,7 @@ xpc_DumpEvalInJSStackFrame(JSContext* cx, uint32_t frameno, const char* text)
 
     DebugDump("js[%d]> %s\n", frameno, text);
 
-    while (nullptr != (fp = JS_FrameIterator(cx, &iter))) {
+    while (nullptr != (fp = JS_BrokenFrameIterator(cx, &iter))) {
         if (num == frameno)
             break;
         num++;

js/xpconnect/src/XPCStack.cpp

@@ -14,8 +14,7 @@ public:
     NS_DECL_ISUPPORTS
     NS_DECL_NSISTACKFRAME
 
-    static nsresult CreateStack(JSContext* cx, JSStackFrame* fp,
-                                XPCJSStackFrame** stack);
+    static nsresult CreateStack(JSContext* cx, XPCJSStackFrame** stack);
 
     static nsresult CreateStackFrameLocation(PRUint32 aLanguage,
                                              const char* aFilename,
@@ -49,10 +48,7 @@ XPCJSStack::CreateStack(JSContext* cx, nsIStackFrame** stack)
     if (!cx)
         return NS_ERROR_FAILURE;
 
-    JSStackFrame *fp = NULL;
-    if (!JS_FrameIterator(cx, &fp))
-        return NS_ERROR_FAILURE;
-    return XPCJSStackFrame::CreateStack(cx, fp, (XPCJSStackFrame**) stack);
+    return XPCJSStackFrame::CreateStack(cx, (XPCJSStackFrame**) stack);
 }
 
 // static
@@ -94,62 +90,55 @@ XPCJSStackFrame::~XPCJSStackFrame()
 NS_IMPL_THREADSAFE_ISUPPORTS1(XPCJSStackFrame, nsIStackFrame)
 
 nsresult
-XPCJSStackFrame::CreateStack(JSContext* cx, JSStackFrame* fp,
-                             XPCJSStackFrame** stack)
+XPCJSStackFrame::CreateStack(JSContext* cx, XPCJSStackFrame** stack)
 {
     static const unsigned MAX_FRAMES = 100;
     unsigned numFrames = 0;
 
     nsRefPtr<XPCJSStackFrame> first = new XPCJSStackFrame();
     nsRefPtr<XPCJSStackFrame> self = first;
-    while (fp && self) {
-        if (!JS_IsScriptFrame(cx, fp)) {
-            self->mLanguage = nsIProgrammingLanguage::CPLUSPLUS;
-        } else {
-            self->mLanguage = nsIProgrammingLanguage::JAVASCRIPT;
-            JSScript* script = JS_GetFrameScript(cx, fp);
-            jsbytecode* pc = JS_GetFramePC(cx, fp);
-            if (script && pc) {
-                JS::AutoEnterFrameCompartment ac;
-                if (ac.enter(cx, fp)) {
-                    const char* filename = JS_GetScriptFilename(cx, script);
-                    if (filename) {
-                        self->mFilename = (char*)
-                            nsMemory::Clone(filename,
-                                            sizeof(char)*(strlen(filename)+1));
-                    }
 
-                    self->mLineno = (PRInt32) JS_PCToLineNumber(cx, script, pc);
+    JS::StackDescription* desc = JS::DescribeStack(cx, MAX_FRAMES);
+    if (!desc)
+        return NS_ERROR_FAILURE;
 
-                    JSFunction* fun = JS_GetFrameFunction(cx, fp);
-                    if (fun) {
-                        JSString *funid = JS_GetFunctionId(fun);
-                        if (funid) {
-                            size_t length = JS_GetStringEncodingLength(cx, funid);
-                            if (length != size_t(-1)) {
-                                self->mFunname = static_cast<char *>(nsMemory::Alloc(length + 1));
-                                if (self->mFunname) {
-                                    JS_EncodeStringToBuffer(funid, self->mFunname, length);
-                                    self->mFunname[length] = '\0';
-                                }
-                            }
+    for (size_t i = 0; i < desc->nframes && self; i++) {
+        self->mLanguage = nsIProgrammingLanguage::JAVASCRIPT;
+
+        JS::AutoEnterScriptCompartment ac;
+        if (ac.enter(cx, desc->frames[i].script)) {
+            const char* filename = JS_GetScriptFilename(cx, desc->frames[i].script);
+            if (filename) {
+                self->mFilename = (char*)
+                    nsMemory::Clone(filename,
+                                    sizeof(char)*(strlen(filename)+1));
+            }
+
+            self->mLineno = desc->frames[i].lineno;
+
+            JSFunction* fun = desc->frames[i].fun;
+            if (fun) {
+                JSString *funid = JS_GetFunctionId(fun);
+                if (funid) {
+                    size_t length = JS_GetStringEncodingLength(cx, funid);
+                    if (length != size_t(-1)) {
+                        self->mFunname = static_cast<char *>(nsMemory::Alloc(length + 1));
+                        if (self->mFunname) {
+                            JS_EncodeStringToBuffer(funid, self->mFunname, length);
+                            self->mFunname[length] = '\0';
                         }
                     }
                 }
-            } else {
-                self->mLanguage = nsIProgrammingLanguage::CPLUSPLUS;
             }
         }
 
-        if (++numFrames > MAX_FRAMES) {
-            fp = NULL;
-        } else if (JS_FrameIterator(cx, &fp)) {
-            XPCJSStackFrame* frame = new XPCJSStackFrame();
-            self->mCaller = frame;
-            self = frame;
-        }
+        XPCJSStackFrame* frame = new XPCJSStackFrame();
+        self->mCaller = frame;
+        self = frame;
     }
 
+    JS::FreeStackDescription(cx, desc);
+
     *stack = first.forget().get();
     return NS_OK;
 }