[runtime] Allocate space for computed property names

src/ast/ast.cc

Index: src/ast/ast.cc
diff --git a/src/ast/ast.cc b/src/ast/ast.cc
index c63f90ecf11f398ebfdecf5c6fd25356dd934f83..b8ea501331d00e015a99d6eecae2c1f3245ad99e 100644
--- a/src/ast/ast.cc
+++ b/src/ast/ast.cc
@@ -582,9 +582,10 @@ void ObjectLiteral::InitDepthAndFlags() {
 void ObjectLiteral::BuildConstantProperties(Isolate* isolate) {
   if (!constant_properties_.is_null()) return;
 
-  // Allocate a fixed array to hold all the constant properties.
-  Handle<FixedArray> constant_properties =
-      isolate->factory()->NewFixedArray(boilerplate_properties_ * 2, TENURED);
+  // Allocate a fixed array to hold all the constant properties and the number
+  // of total properties.
+  Handle<FixedArray> constant_properties = isolate->factory()->NewFixedArray(

[Toon Verwaest, 2017/01/18 08:49:53]

Handle<ConstantProperties> =
isolate->factory()->NewConstantProperties(properties()->length(),
boilerplate_properties_);

which does 

size = boilerplate_properties * 2;
if (properties != boilerplate_properties) size++;
Handle<ConstantProperties> constant_properties =
Handle<ConstantProperties>::cast(NewFixedArray(size));
if (properties != boilerplate_properties) {
  constant_properties->set_property_count(properties);
}
return constant_properties;

[Franzi, 2017/01/18 14:23:10]

Acknowledged.

+      boilerplate_properties_ * 2 + 1, TENURED);
 
   int position = 0;
   for (int i = 0; i < properties()->length(); i++) {
@@ -622,6 +623,10 @@ void ObjectLiteral::BuildConstantProperties(Isolate* isolate) {
     constant_properties->set(position++, *value);
   }
 
+  Handle<Object> total_properties =
+      isolate->factory()->NewNumberFromInt(total_properties_);

[gsathya, 2017/01/17 18:31:39]

total_properties_ can be calculated using the above for loop right? then we
don't need this to be a property of ObjectLiteral

[Franzi, 2017/01/17 19:08:45]

The loop breaks on the first computed property, and I'd have to do the rest of
the iteration to count all boilerplate properties. Is that better than an extra
field in ObjectLiteral?

[Toon Verwaest, 2017/01/18 08:49:53]

I think what he means is that DCHECK_EQ(total_properties_,
properties()->length()); in which case we don't need a separate
total_properties_ field on the ast node (we do need it in the fixed array
obviously).

[Franzi, 2017/01/18 14:23:10]

As discussed, it's not equal if __proto__ is present. I added a bit for
has_seen_proto as Sathya suggested. Dropped the total_properties. 

+  constant_properties->set(position, *total_properties);
+
   constant_properties_ = constant_properties;
 }