[interpreter] Add a fast path for dynamic local load

src/interpreter/bytecode-array-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/interpreter/bytecode-array-builder.h"
 
 #include "src/globals.h"
 #include "src/interpreter/bytecode-array-writer.h"
 #include "src/interpreter/bytecode-dead-code-optimizer.h"
 #include "src/interpreter/bytecode-label.h"
@@ skipping 277 matching lines @@
 BytecodeArrayBuilder& BytecodeArrayBuilder::LoadLookupSlot(
     const Handle<String> name, TypeofMode typeof_mode) {
   Bytecode bytecode = (typeof_mode == INSIDE_TYPEOF)
                           ? Bytecode::kLdaLookupSlotInsideTypeof
                           : Bytecode::kLdaLookupSlot;
   size_t name_index = GetConstantPoolEntry(name);
   Output(bytecode, UnsignedOperand(name_index));
   return *this;
 }
 
+BytecodeArrayBuilder& BytecodeArrayBuilder::LoadLookupContextSlot(
+    const Handle<String> name, TypeofMode typeof_mode, int slot_index,
+    int depth) {
+  Bytecode bytecode = (typeof_mode == INSIDE_TYPEOF)
+                          ? Bytecode::kLdaLookupContextSlotInsideTypeof
+                          : Bytecode::kLdaLookupContextSlot;
+  size_t name_index = GetConstantPoolEntry(name);
+  Output(bytecode, UnsignedOperand(name_index), UnsignedOperand(slot_index),
+         UnsignedOperand(depth));
+  return *this;
+}
+
 BytecodeArrayBuilder& BytecodeArrayBuilder::StoreLookupSlot(
     const Handle<String> name, LanguageMode language_mode) {
   Bytecode bytecode = BytecodeForStoreLookupSlot(language_mode);
   size_t name_index = GetConstantPoolEntry(name);
   Output(bytecode, UnsignedOperand(name_index));
   return *this;
 }
 
 BytecodeArrayBuilder& BytecodeArrayBuilder::LoadNamedProperty(
     Register object, const Handle<Name> name, int feedback_slot) {
@@ skipping 694 matching lines @@
       return Bytecode::kTailCall;
     default:
       UNREACHABLE();
   }
   return Bytecode::kIllegal;
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8