[interpreter] Add a fast path for dynamic local load

src/compiler/bytecode-graph-builder.cc

Index: src/compiler/bytecode-graph-builder.cc
diff --git a/src/compiler/bytecode-graph-builder.cc b/src/compiler/bytecode-graph-builder.cc
index 39c0397181346f1ccba477059b9905a5a420c99d..5fff5a44e500cd0c7ada887d43f9d823973ab648 100644
--- a/src/compiler/bytecode-graph-builder.cc
+++ b/src/compiler/bytecode-graph-builder.cc
@@ -886,6 +886,33 @@ void BytecodeGraphBuilder::VisitLdaLookupSlotInsideTypeof() {
   BuildLdaLookupSlot(TypeofMode::INSIDE_TYPEOF);
 }
 
+void BytecodeGraphBuilder::BuildLdaLookupContextSlot(TypeofMode typeof_mode) {
+  // TODO(leszeks): Build the fast path here

[rmcilroy, 2016/09/16 08:56:55]

fullstop after comments (throughout cl)

[Leszek Swirski, 2016/09/16 10:46:54]

Done.

+
+  // 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();