Use a different map to distinguish eval contexts

src/compiler/js-create-lowering.cc

Index: src/compiler/js-create-lowering.cc
diff --git a/src/compiler/js-create-lowering.cc b/src/compiler/js-create-lowering.cc
index 23ae27b36818c3ddde5c28c551e9f55b5ad478d2..3371f9884dfe19b2f89c1ed942756eac43211298 100644
--- a/src/compiler/js-create-lowering.cc
+++ b/src/compiler/js-create-lowering.cc
@@ -215,6 +215,8 @@ Reduction JSCreateLowering::Reduce(Node* node) {
       return ReduceJSCreateLiteral(node);
     case IrOpcode::kJSCreateFunctionContext:
       return ReduceJSCreateFunctionContext(node);
+    case IrOpcode::kJSCreateEvalContext:
+      return ReduceJSCreateEvalContext(node);
     case IrOpcode::kJSCreateWithContext:
       return ReduceJSCreateWithContext(node);
     case IrOpcode::kJSCreateCatchContext:
@@ -783,6 +785,38 @@ Reduction JSCreateLowering::ReduceJSCreateFunctionContext(Node* node) {
   return NoChange();
 }
 
+Reduction JSCreateLowering::ReduceJSCreateEvalContext(Node* node) {
+  DCHECK_EQ(IrOpcode::kJSCreateEvalContext, node->opcode());
+  int slot_count = OpParameter<int>(node->op());
+  Node* const closure = NodeProperties::GetValueInput(node, 0);
+
+  // Use inline allocation for function contexts up to a size limit.
+  if (slot_count < kFunctionContextAllocationLimit) {
+    // JSCreateFunctionContext[slot_count < limit]](fun)
+    Node* effect = NodeProperties::GetEffectInput(node);
+    Node* control = NodeProperties::GetControlInput(node);
+    Node* context = NodeProperties::GetContextInput(node);
+    Node* extension = jsgraph()->TheHoleConstant();
+    AllocationBuilder a(jsgraph(), effect, control);
+    STATIC_ASSERT(Context::MIN_CONTEXT_SLOTS == 4);  // Ensure fully covered.
+    int context_length = slot_count + Context::MIN_CONTEXT_SLOTS;
+    a.AllocateArray(context_length, factory()->eval_context_map());
+    a.Store(AccessBuilder::ForContextSlot(Context::CLOSURE_INDEX), closure);
+    a.Store(AccessBuilder::ForContextSlot(Context::PREVIOUS_INDEX), context);
+    a.Store(AccessBuilder::ForContextSlot(Context::EXTENSION_INDEX), extension);
+    a.Store(AccessBuilder::ForContextSlot(Context::NATIVE_CONTEXT_INDEX),
+            jsgraph()->HeapConstant(native_context()));
+    for (int i = Context::MIN_CONTEXT_SLOTS; i < context_length; ++i) {
+      a.Store(AccessBuilder::ForContextSlot(i), jsgraph()->UndefinedConstant());
+    }
+    RelaxControls(node);
+    a.FinishAndChange(node);
+    return Changed(node);
+  }
+
+  return NoChange();
+}
+
 Reduction JSCreateLowering::ReduceJSCreateWithContext(Node* node) {
   DCHECK_EQ(IrOpcode::kJSCreateWithContext, node->opcode());
   Handle<ScopeInfo> scope_info = OpParameter<Handle<ScopeInfo>>(node);