Provide a counter for thrown JavaScript errors per context

src/factory.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/conversions.h"
@@ skipping 708 matching lines @@
   return symbol;
 }
 
 
 Handle<Context> Factory::NewNativeContext() {
   Handle<FixedArray> array =
       NewFixedArray(Context::NATIVE_CONTEXT_SLOTS, TENURED);
   array->set_map_no_write_barrier(*native_context_map());
   Handle<Context> context = Handle<Context>::cast(array);
   context->set_js_array_maps(*undefined_value());
+  context->set_exceptions_thrown(Smi::FromInt(0));
   DCHECK(context->IsNativeContext());
   return context;
 }
 
 
 Handle<Context> Factory::NewScriptContext(Handle<JSFunction> function,
                                           Handle<ScopeInfo> scope_info) {
   Handle<FixedArray> array =
       NewFixedArray(scope_info->ContextLength(), TENURED);
   array->set_map_no_write_barrier(*script_context_map());
@@ skipping 413 matching lines @@
     return undefined_value();
   }
   return result;
 }
 
 
 #define DEFINE_ERROR(NAME, name)                                              \
   Handle<Object> Factory::New##NAME(MessageTemplate::Template template_index, \
                                     Handle<Object> arg0, Handle<Object> arg1, \
                                     Handle<Object> arg2) {                    \
+    isolate()->native_context()->IncrementExceptionsThrown();                 \

[jochen (gone - plz use gerrit), 2015/10/30 12:13:38]

this looks wrong. It's not uncommon to do

var a = new Error().stack;

to capture e.g. the creation site of an object

[Yang, 2015/10/30 13:01:02]

As discussed offline, I suggested to do it in %FormatMessageString.

[Michael Hablich, 2015/10/30 15:55:03]

I moved the call to %FormatMessageString. During the build %FormatMessageString
is run once and the result is stored. This resulted in the weird behavior I
observed before. Initializing the counter with -1 fixes this.

     return NewError(isolate()->name##_function(), template_index, arg0, arg1, \
                     arg2);                                                    \
   }
 DEFINE_ERROR(Error, error)
 DEFINE_ERROR(EvalError, eval_error)
 DEFINE_ERROR(RangeError, range_error)
 DEFINE_ERROR(ReferenceError, reference_error)
 DEFINE_ERROR(SyntaxError, syntax_error)
 DEFINE_ERROR(TypeError, type_error)
 #undef DEFINE_ERROR
@@ skipping 1217 matching lines @@
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 }  // namespace internal
 }  // namespace v8