[interpreter] Add a fast path for dynamic local load

test/cctest/interpreter/test-interpreter.cc

Index: test/cctest/interpreter/test-interpreter.cc
diff --git a/test/cctest/interpreter/test-interpreter.cc b/test/cctest/interpreter/test-interpreter.cc
index 26c11890f52d7b1b2cfbf027f6249b506c36e94f..99b99734ae280bc770f3ae0922fd6cbc8eb07ffc 100644
--- a/test/cctest/interpreter/test-interpreter.cc
+++ b/test/cctest/interpreter/test-interpreter.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <tuple>
+
 #include "src/v8.h"
 
 #include "src/execution.h"
@@ -3862,6 +3864,47 @@ TEST(InterpreterLookupSlot) {
   }
 }
 
+TEST(InterpreterLookupContextSlot) {
+  HandleAndZoneScope handles;
+  Isolate* isolate = handles.main_isolate();
+
+  const char* inner_function_prologue = "function inner() {";
+  const char* inner_function_epilogue = "};";
+  const char* outer_function_epilogue = "return inner();";
+
+  std::tuple<const char*, const char*, Handle<Object>> lookup_slot[] = {
+      // Eval in inner context.
+      std::make_tuple("var x = 0;", "eval(''); return x;",
+                      handle(Smi::FromInt(0), isolate)),
+      std::make_tuple("var x = 0;", "eval('var x = 1'); return x;",
+                      handle(Smi::FromInt(1), isolate)),
+      std::make_tuple("var x = 0;",
+                      "'use strict'; eval('var x = 1'); return x;",
+                      handle(Smi::FromInt(0), isolate)),
+      // Eval in outer context.
+      std::make_tuple("var x = 0; eval('');", "return x;",
+                      handle(Smi::FromInt(0), isolate)),
+      std::make_tuple("var x = 0; eval('var x = 1');", "return x;",
+                      handle(Smi::FromInt(1), isolate)),
+      std::make_tuple("'use strict'; var x = 0; eval('var x = 1');",
+                      "return x;", handle(Smi::FromInt(0), isolate)),
+  };
+
+  for (size_t i = 0; i < arraysize(lookup_slot); i++) {
+    std::string body = std::string(std::get<0>(lookup_slot[i])) +
+                       std::string(inner_function_prologue) +
+                       std::string(std::get<1>(lookup_slot[i])) +
+                       std::string(inner_function_epilogue) +
+                       std::string(outer_function_epilogue);
+    std::string script = InterpreterTester::SourceForBody(body.c_str());
+
+    InterpreterTester tester(isolate, script.c_str());
+    auto callable = tester.GetCallable<>();
+
+    Handle<i::Object> return_value = callable().ToHandleChecked();
+    CHECK(return_value->SameValue(*std::get<2>(lookup_slot[i])));
+  }
+}
 
 TEST(InterpreterCallLookupSlot) {
   HandleAndZoneScope handles;