[interpreter] Add a fast path for dynamic local load

src/compiler/bytecode-graph-builder.cc

 // Copyright 2015 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/compiler/bytecode-graph-builder.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/compilation-info.h"
 #include "src/compiler/bytecode-branch-analysis.h"
@@ skipping 870 matching lines @@
 }
 
 void BytecodeGraphBuilder::VisitLdaLookupSlot() {
   BuildLdaLookupSlot(TypeofMode::NOT_INSIDE_TYPEOF);
 }
 
 void BytecodeGraphBuilder::VisitLdaLookupSlotInsideTypeof() {
   BuildLdaLookupSlot(TypeofMode::INSIDE_TYPEOF);
 }
 
+void BytecodeGraphBuilder::BuildLdaLookupContextSlot(TypeofMode typeof_mode) {
+  // TODO(leszeks): Build the fast path here.
+
+  // Slow path, do a runtime load lookup.
+  {
+    FrameStateBeforeAndAfter states(this);
+
+    Node* name =
+        jsgraph()->Constant(bytecode_iterator().GetConstantForIndexOperand(0));
+
+    const Operator* op =
+        javascript()->CallRuntime(typeof_mode == TypeofMode::NOT_INSIDE_TYPEOF
+                                      ? Runtime::kLoadLookupSlot
+                                      : Runtime::kLoadLookupSlotInsideTypeof);
+    Node* value = NewNode(op, name);
+    environment()->BindAccumulator(value, &states);
+  }
+}
+
+void BytecodeGraphBuilder::VisitLdaLookupContextSlot() {
+  BuildLdaLookupContextSlot(TypeofMode::NOT_INSIDE_TYPEOF);
+}
+
+void BytecodeGraphBuilder::VisitLdaLookupContextSlotInsideTypeof() {
+  BuildLdaLookupContextSlot(TypeofMode::INSIDE_TYPEOF);
+}
+
 void BytecodeGraphBuilder::BuildStaLookupSlot(LanguageMode language_mode) {
   FrameStateBeforeAndAfter states(this);
   Node* value = environment()->LookupAccumulator();
   Node* name =
       jsgraph()->Constant(bytecode_iterator().GetConstantForIndexOperand(0));
   const Operator* op = javascript()->CallRuntime(
       is_strict(language_mode) ? Runtime::kStoreLookupSlot_Strict
                                : Runtime::kStoreLookupSlot_Sloppy);
   Node* store = NewNode(op, name, value);
   environment()->BindAccumulator(store, &states);
@@ skipping 1189 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8