[stack-trace] Remove JSArray wrapper for simple stack traces

This CL changes the Symbol "stack_trace_symbol" to directly hold a
FrameArray instead of wrapping it with a JSArray first.

Bug: v8:9115
Change-Id: I2ac0b1fb380211568abdc6d9f50431c405349dec
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1564060Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60801}

src/isolate.cc

@@ -1111,7 +1111,7 @@ Handle<Object> CaptureStackTrace(Isolate* isolate, Handle<Object> caller,
 
   // TODO(yangguo): Queue this structured stack trace for preprocessing on GC.
   if (options.capture_result == CaptureStackTraceOptions::RAW_FRAME_ARRAY) {
-    return isolate->factory()->NewJSArrayWithElements(builder.GetElements());
+    return builder.GetElements();
   }
   return builder.GetElementsAsStackTraceFrameArray();
 }
@@ -2110,11 +2110,9 @@ bool Isolate::ComputeLocationFromStackTrace(MessageLocation* target,
   Handle<Name> key = factory()->stack_trace_symbol();
   Handle<Object> property =
       JSReceiver::GetDataProperty(Handle<JSObject>::cast(exception), key);
-  if (!property->IsJSArray()) return false;
-  Handle<JSArray> simple_stack_trace = Handle<JSArray>::cast(property);
+  if (!property->IsFixedArray()) return false;
 
-  Handle<FrameArray> elements(FrameArray::cast(simple_stack_trace->elements()),
-                              this);
+  Handle<FrameArray> elements = Handle<FrameArray>::cast(property);
 
   const int frame_count = elements->FrameCount();
   for (int i = 0; i < frame_count; i++) {

src/messages.cc

@@ -974,12 +974,8 @@ class PrepareStackTraceScope {
 MaybeHandle<Object> ErrorUtils::FormatStackTrace(Isolate* isolate,
                                                  Handle<JSObject> error,
                                                  Handle<Object> raw_stack) {
-  DCHECK(raw_stack->IsJSArray());
-  Handle<JSArray> raw_stack_array = Handle<JSArray>::cast(raw_stack);
-
-  DCHECK(raw_stack_array->elements()->IsFixedArray());
-  Handle<FrameArray> elems(FrameArray::cast(raw_stack_array->elements()),
-                           isolate);
+  DCHECK(raw_stack->IsFixedArray());
+  Handle<FrameArray> elems = Handle<FrameArray>::cast(raw_stack);
 
   const bool in_recursion = isolate->formatting_stack_trace();
   if (!in_recursion) {

test/cctest/heap/test-heap.cc

@@ -3553,12 +3553,8 @@ void DetailedErrorStackTraceTest(const char* src,
   Isolate* isolate = CcTest::i_isolate();
   Handle<Name> key = isolate->factory()->stack_trace_symbol();
 
-  Handle<FrameArray> stack_trace(
-      FrameArray::cast(
-          Handle<JSArray>::cast(
-              Object::GetProperty(isolate, exception, key).ToHandleChecked())
-              ->elements()),
-      isolate);
+  Handle<FrameArray> stack_trace(Handle<FrameArray>::cast(
+      Object::GetProperty(isolate, exception, key).ToHandleChecked()));
 
   test(stack_trace);
 }
@@ -5150,8 +5146,8 @@ TEST(PreprocessStackTrace) {
       Object::GetElement(isolate, stack_trace, 3).ToHandleChecked();
   CHECK(pos->IsSmi());
 
-  Handle<JSArray> stack_trace_array = Handle<JSArray>::cast(stack_trace);
-  int array_length = Smi::ToInt(stack_trace_array->length());
+  Handle<FrameArray> frame_array = Handle<FrameArray>::cast(stack_trace);
+  int array_length = frame_array->FrameCount();
   for (int i = 0; i < array_length; i++) {
     Handle<Object> element =
         Object::GetElement(isolate, stack_trace, i).ToHandleChecked();