Add additional flags to control array abuse tracing

src/elements.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 486 matching lines @@
     if (raw_frame->unchecked_code() == apply_builtin) {
       PrintF("apply from ");
       it.Advance();
       raw_frame = it.frame();
     }
   }
   JavaScriptFrame::PrintTop(stdout, false, true);
 }
 
 
-void CheckArrayAbuse(JSObject* obj, const char* op, uint32_t key) {
+void CheckArrayAbuse(JSObject* obj, const char* op, uint32_t key,
+                     bool allow_list_append_growth) {
   Object* raw_length = NULL;
   const char* elements_type = "array";
   if (obj->IsJSArray()) {
     JSArray* array = JSArray::cast(obj);
     raw_length = array->length();
   } else {
     raw_length = Smi::FromInt(obj->elements()->length());
     elements_type = "object";
   }
 
   if (raw_length->IsNumber()) {
     double n = raw_length->Number();
     if (FastI2D(FastD2UI(n)) == n) {
       int32_t int32_length = DoubleToInt32(n);
-      if (key >= static_cast<uint32_t>(int32_length)) {
+      uint32_t compare_length = static_cast<uint32_t>(int32_length);
+      if (allow_list_append_growth) compare_length++;
+      if (key >= compare_length) {
         PrintF("[OOB %s %s (%s length = %d, element accessed = %d) in ",
                elements_type, op, elements_type,
                static_cast<int>(int32_length),
                static_cast<int>(key));
         TraceTopFrame();
         PrintF("]\n");
       }
     } else {
       PrintF("[%s elements length not integer value in ", elements_type);
       TraceTopFrame();
@@ skipping 88 matching lines @@
   }
 
   MUST_USE_RESULT virtual MaybeObject* Get(Object* receiver,
                                            JSObject* holder,
                                            uint32_t key,
                                            FixedArrayBase* backing_store) {
     if (backing_store == NULL) {
       backing_store = holder->elements();
     }
 
-    if (FLAG_trace_array_abuse) {
-      CheckArrayAbuse(holder, "element read", key);
+    if (!IsExternalArrayElementsKind(ElementsTraits::Kind) &&
+        FLAG_trace_js_array_abuse) {
+      CheckArrayAbuse(holder, "elements read", key);
+    }
+
+    if (IsExternalArrayElementsKind(ElementsTraits::Kind) &&
+        FLAG_trace_external_array_abuse) {
+      CheckArrayAbuse(holder, "external elements read", key);
     }
 
     return ElementsAccessorSubclass::GetImpl(
         receiver, holder, key, backing_store);
   }
 
   MUST_USE_RESULT static MaybeObject* GetImpl(Object* receiver,
                                               JSObject* obj,
                                               uint32_t key,
                                               FixedArrayBase* backing_store) {
@@ skipping 1315 matching lines @@
   if (!maybe_obj->To(&new_backing_store)) return maybe_obj;
   new_backing_store->set(0, length);
   { MaybeObject* result = array->SetContent(new_backing_store);
     if (result->IsFailure()) return result;
   }
   return array;
 }
 
 
 } }  // namespace v8::internal