[interpreter] Add a fast path for dynamic local load

test/unittests/interpreter/bytecode-array-builder-unittest.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/v8.h"
 
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/bytecode-array-iterator.h"
 #include "src/interpreter/bytecode-label.h"
 #include "src/interpreter/bytecode-register-allocator.h"
@@ skipping 82 matching lines @@
       .StoreKeyedProperty(reg, reg, 0, LanguageMode::SLOPPY)
       .StoreNamedProperty(reg, name, 0, LanguageMode::STRICT)
       .StoreKeyedProperty(reg, reg, 0, LanguageMode::STRICT);
 
   // Emit load / store lookup slots.
   builder.LoadLookupSlot(name, TypeofMode::NOT_INSIDE_TYPEOF)
       .LoadLookupSlot(name, TypeofMode::INSIDE_TYPEOF)
       .StoreLookupSlot(name, LanguageMode::SLOPPY)
       .StoreLookupSlot(name, LanguageMode::STRICT);
 
+  // Emit load / store lookup slots with context fast paths.
+  builder.LoadLookupContextSlot(name, TypeofMode::NOT_INSIDE_TYPEOF, 1, 0)
+      .LoadLookupContextSlot(name, TypeofMode::INSIDE_TYPEOF, 1, 0);
+
   // Emit closure operations.
   builder.CreateClosure(0, NOT_TENURED);
 
   // Emit create context operation.
   builder.CreateBlockContext(factory->NewScopeInfo(1));
   builder.CreateCatchContext(reg, name, factory->NewScopeInfo(1));
   builder.CreateFunctionContext(1);
   builder.CreateWithContext(reg, factory->NewScopeInfo(1));
 
   // Emit literal creation operations.
@@ skipping 644 matching lines @@
     iterator.Advance();
   }
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kReturn);
   iterator.Advance();
   CHECK(iterator.done());
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8