[turbofan] Do not optimize with/block-context allocation in global code.

src/compiler/js-typed-lowering.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/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 1171 matching lines @@
     return Changed(node);
   }
 
   return NoChange();
 }
 
 
 Reduction JSTypedLowering::ReduceJSCreateWithContext(Node* node) {
   DCHECK_EQ(IrOpcode::kJSCreateWithContext, node->opcode());
   Node* const input = NodeProperties::GetValueInput(node, 0);
+  Node* const closure = NodeProperties::GetValueInput(node, 1);
   Type* input_type = NodeProperties::GetBounds(input).upper;
-  if (FLAG_turbo_allocate && input_type->Is(Type::Receiver())) {
+  // The closure can be NumberConstant(0) if the closure is global code
+  // (rather than a function). We exclude that case here.
+  // TODO(jarin) Find a better way to check that the closure is a function.
+  if (FLAG_turbo_allocate && input_type->Is(Type::Receiver()) &&
+      closure->opcode() != IrOpcode::kNumberConstant) {
     // JSCreateWithContext(o:receiver, f)
     Node* const effect = NodeProperties::GetEffectInput(node);
     Node* const control = NodeProperties::GetControlInput(node);
-    Node* const closure = NodeProperties::GetValueInput(node, 1);
     Node* const context = NodeProperties::GetContextInput(node);
     Node* const load = graph()->NewNode(
         simplified()->LoadField(
             AccessBuilder::ForContextSlot(Context::GLOBAL_OBJECT_INDEX)),
         context, effect, control);
     AllocationBuilder a(jsgraph(), simplified(), effect, control);
     STATIC_ASSERT(Context::MIN_CONTEXT_SLOTS == 4);  // Ensure fully covered.
     a.AllocateArray(Context::MIN_CONTEXT_SLOTS, factory()->with_context_map());
     a.Store(AccessBuilder::ForContextSlot(Context::CLOSURE_INDEX), closure);
     a.Store(AccessBuilder::ForContextSlot(Context::PREVIOUS_INDEX), context);
@@ skipping 16 matching lines @@
   DCHECK_EQ(IrOpcode::kJSCreateBlockContext, node->opcode());
   Node* const input = NodeProperties::GetValueInput(node, 0);
   HeapObjectMatcher minput(input);
   DCHECK(minput.HasValue());  // TODO(mstarzinger): Make ScopeInfo static.
   int context_length =
       Handle<ScopeInfo>::cast(minput.Value().handle())->ContextLength();
   if (FLAG_turbo_allocate && context_length < kBlockContextAllocationLimit) {
     // JSCreateBlockContext(s:scope[length < limit], f)
     Node* const effect = NodeProperties::GetEffectInput(node);
     Node* const control = NodeProperties::GetControlInput(node);
     Node* const closure = NodeProperties::GetValueInput(node, 1);

[Michael Starzinger, 2015/08/19 14:19:24]

The same can happen for block contexts as well.

[Jarin, 2015/08/20 05:26:01]

Done.

     Node* const context = NodeProperties::GetContextInput(node);
     Node* const load = graph()->NewNode(
         simplified()->LoadField(
             AccessBuilder::ForContextSlot(Context::GLOBAL_OBJECT_INDEX)),
         context, effect, control);
     AllocationBuilder a(jsgraph(), simplified(), effect, control);
     STATIC_ASSERT(Context::MIN_CONTEXT_SLOTS == 4);  // Ensure fully covered.
     a.AllocateArray(context_length, factory()->block_context_map());
     a.Store(AccessBuilder::ForContextSlot(Context::CLOSURE_INDEX), closure);
     a.Store(AccessBuilder::ForContextSlot(Context::PREVIOUS_INDEX), context);
@@ skipping 462 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSTypedLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8