Allow closures to be optimized if outer contexts that call eval are all in strict mode.

src/scopeinfo.cc

-// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Copyright 2011 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
 //       with the distribution.
@@ skipping 33 matching lines @@
   int y = (t != NULL ? t->index() : 0);
   // Consider sorting them according to type as well?
   return x - y;
 }
 
 
 template<class Allocator>
 ScopeInfo<Allocator>::ScopeInfo(Scope* scope)
     : function_name_(FACTORY->empty_symbol()),
       calls_eval_(scope->calls_eval()),
+      is_strict_mode_(scope->is_strict_mode()),
       parameters_(scope->num_parameters()),
       stack_slots_(scope->num_stack_slots()),
       context_slots_(scope->num_heap_slots()),
       context_modes_(scope->num_heap_slots()) {
   // Add parameters.
   for (int i = 0; i < scope->num_parameters(); i++) {
     ASSERT(parameters_.length() == i);
     parameters_.Add(scope->parameter(i)->name());
   }
 
@@ skipping 176 matching lines @@
   : function_name_(FACTORY->empty_symbol()),
     parameters_(4),
     stack_slots_(8),
     context_slots_(8),
     context_modes_(8) {
   if (data->length() > 0) {
     Object** p0 = data->data_start();
     Object** p = p0;
     p = ReadSymbol(p, &function_name_);
     p = ReadBool(p, &calls_eval_);
+    p = ReadBool(p, &is_strict_mode_);
     p = ReadList<Allocator>(p, &context_slots_, &context_modes_);
     p = ReadList<Allocator>(p, &parameters_);
     p = ReadList<Allocator>(p, &stack_slots_);
     ASSERT((p - p0) == FixedArray::cast(data)->length());
   }
 }
 
 
 static inline Object** WriteInt(Object** p, int x) {
   *p++ = Smi::FromInt(x);
@@ skipping 33 matching lines @@
   for (int i = 0; i < n; i++) {
     p = WriteSymbol(p, list->at(i));
     p = WriteInt(p, modes->at(i));
   }
   return p;
 }
 
 
 template<class Allocator>
 Handle<SerializedScopeInfo> ScopeInfo<Allocator>::Serialize() {
-  // function name, calls eval, length for 3 tables:
-  const int extra_slots = 1 + 1 + 3;
+  // function name, calls eval, is_strict_mode, length for 3 tables:
+  const int extra_slots = 1 + 1 + 1 + 3;
   int length = extra_slots +
                context_slots_.length() * 2 +
                parameters_.length() +
                stack_slots_.length();
 
   Handle<SerializedScopeInfo> data(
       SerializedScopeInfo::cast(*FACTORY->NewFixedArray(length, TENURED)));
   AssertNoAllocation nogc;
 
   Object** p0 = data->data_start();
   Object** p = p0;
   p = WriteSymbol(p, function_name_);
   p = WriteBool(p, calls_eval_);
+  p = WriteBool(p, is_strict_mode_);
   p = WriteList(p, &context_slots_, &context_modes_);
   p = WriteList(p, &parameters_);
   p = WriteList(p, &stack_slots_);
   ASSERT((p - p0) == length);
 
   return data;
 }
 
 
 template<class Allocator>
@@ skipping 27 matching lines @@
 }
 
 
 SerializedScopeInfo* SerializedScopeInfo::Empty() {
   return reinterpret_cast<SerializedScopeInfo*>(HEAP->empty_fixed_array());
 }
 
 
 Object** SerializedScopeInfo::ContextEntriesAddr() {
   ASSERT(length() > 0);
-  return data_start() + 2;  // +2 for function name and calls eval.
+  // +3 for function name, calls eval, strict mode.
+  return data_start() + 3;
 }
 
 
 Object** SerializedScopeInfo::ParameterEntriesAddr() {
   ASSERT(length() > 0);
   Object** p = ContextEntriesAddr();
   int number_of_context_slots;
   p = ReadInt(p, &number_of_context_slots);
   return p + number_of_context_slots*2;  // *2 for pairs
 }
 
 
 Object** SerializedScopeInfo::StackSlotEntriesAddr() {
   ASSERT(length() > 0);
   Object** p = ParameterEntriesAddr();
   int number_of_parameter_slots;
   p = ReadInt(p, &number_of_parameter_slots);
   return p + number_of_parameter_slots;
 }
 
 
 bool SerializedScopeInfo::CallsEval() {
   if (length() > 0) {
     Object** p = data_start() + 1;  // +1 for function name.
     bool calls_eval;
     p = ReadBool(p, &calls_eval);
     return calls_eval;
   }
-  return true;
+  return false;
 }
 
 
+bool SerializedScopeInfo::IsStrictMode() {
+  if (length() > 0) {
+    Object** p = data_start() + 2;  // +2 for function name, calls eval.
+    bool strict_mode;
+    p = ReadBool(p, &strict_mode);
+    return strict_mode;
+  }
+  return false;
+}
+
+
 int SerializedScopeInfo::NumberOfStackSlots() {
   if (length() > 0) {
     Object** p = StackSlotEntriesAddr();
     int number_of_stack_slots;
     ReadInt(p, &number_of_stack_slots);
     return number_of_stack_slots;
   }
   return 0;
 }
 
@@ skipping 213 matching lines @@
 }
 #endif  // DEBUG
 
 
 // Make sure the classes get instantiated by the template system.
 template class ScopeInfo<FreeStoreAllocationPolicy>;
 template class ScopeInfo<PreallocatedStorage>;
 template class ScopeInfo<ZoneListAllocationPolicy>;
 
 } }  // namespace v8::internal