[interpreter] Add fast path for dynamic global lookups

src/interpreter/interpreter.cc

Index: src/interpreter/interpreter.cc
diff --git a/src/interpreter/interpreter.cc b/src/interpreter/interpreter.cc
index 0c1f945d0fd3322f146bc3449409ec5a5734fbb9..999a795a56fbcb37406055a31491d347b5bf6efa 100644
--- a/src/interpreter/interpreter.cc
+++ b/src/interpreter/interpreter.cc
@@ -421,16 +421,14 @@ void Interpreter::DoMov(InterpreterAssembler* assembler) {
   __ Dispatch();
 }
 
-Node* Interpreter::BuildLoadGlobal(Callable ic,
+Node* Interpreter::BuildLoadGlobal(Callable ic, Node* context,
+                                   Node* feedback_slot,
                                    InterpreterAssembler* assembler) {
   typedef LoadGlobalWithVectorDescriptor Descriptor;
-  // Get the global object.
-  Node* context = __ GetContext();
 
   // Load the global via the LoadGlobalIC.
   Node* code_target = __ HeapConstant(ic.code());
-  Node* raw_slot = __ BytecodeOperandIdx(0);
-  Node* smi_slot = __ SmiTag(raw_slot);
+  Node* smi_slot = __ SmiTag(feedback_slot);
   Node* type_feedback_vector = __ LoadTypeFeedbackVector();
   return __ CallStub(ic.descriptor(), code_target, context,
                      Arg(Descriptor::kSlot, smi_slot),
@@ -444,7 +442,11 @@ Node* Interpreter::BuildLoadGlobal(Callable ic,
 void Interpreter::DoLdaGlobal(InterpreterAssembler* assembler) {
   Callable ic =
       CodeFactory::LoadGlobalICInOptimizedCode(isolate_, NOT_INSIDE_TYPEOF);
-  Node* result = BuildLoadGlobal(ic, assembler);
+
+  Node* context = __ GetContext();
+
+  Node* raw_slot = __ BytecodeOperandIdx(0);
+  Node* result = BuildLoadGlobal(ic, context, raw_slot, assembler);
   __ SetAccumulator(result);
   __ Dispatch();
 }
@@ -456,7 +458,11 @@ void Interpreter::DoLdaGlobal(InterpreterAssembler* assembler) {
 void Interpreter::DoLdrGlobal(InterpreterAssembler* assembler) {
   Callable ic =
       CodeFactory::LoadGlobalICInOptimizedCode(isolate_, NOT_INSIDE_TYPEOF);
-  Node* result = BuildLoadGlobal(ic, assembler);
+
+  Node* context = __ GetContext();
+
+  Node* raw_slot = __ BytecodeOperandIdx(0);
+  Node* result = BuildLoadGlobal(ic, context, raw_slot, assembler);
   Node* destination = __ BytecodeOperandReg(1);
   __ StoreRegister(result, destination);
   __ Dispatch();
@@ -469,7 +475,11 @@ void Interpreter::DoLdrGlobal(InterpreterAssembler* assembler) {
 void Interpreter::DoLdaGlobalInsideTypeof(InterpreterAssembler* assembler) {
   Callable ic =
       CodeFactory::LoadGlobalICInOptimizedCode(isolate_, INSIDE_TYPEOF);
-  Node* result = BuildLoadGlobal(ic, assembler);
+
+  Node* context = __ GetContext();
+
+  Node* raw_slot = __ BytecodeOperandIdx(0);
+  Node* result = BuildLoadGlobal(ic, context, raw_slot, assembler);
   __ SetAccumulator(result);
   __ Dispatch();
 }
@@ -563,8 +573,8 @@ void Interpreter::DoStaContextSlot(InterpreterAssembler* assembler) {
 
 void Interpreter::DoLdaLookupSlot(Runtime::FunctionId function_id,
                                   InterpreterAssembler* assembler) {
-  Node* index = __ BytecodeOperandIdx(0);
-  Node* name = __ LoadConstantPoolEntry(index);
+  Node* name_index = __ BytecodeOperandIdx(0);
+  Node* name = __ LoadConstantPoolEntry(name_index);
   Node* context = __ GetContext();
   Node* result = __ CallRuntime(function_id, context, name);
   __ SetAccumulator(result);
@@ -634,6 +644,56 @@ void Interpreter::DoLdaLookupContextSlotInsideTypeof(
   DoLdaLookupContextSlot(Runtime::kLoadLookupSlotInsideTypeof, assembler);
 }
 
+void Interpreter::DoLdaLookupGlobalSlot(Runtime::FunctionId function_id,
+                                        InterpreterAssembler* assembler) {
+  Node* context = __ GetContext();
+  Node* name_index = __ BytecodeOperandIdx(0);
+  Node* feedback_slot = __ BytecodeOperandIdx(1);
+  Node* depth = __ BytecodeOperandUImm(2);
+
+  Label slowpath(assembler, Label::kDeferred);
+
+  // Check for context extensions to allow the fast path
+  __ GotoIfHasContextExtensionUpToDepth(context, depth, &slowpath);
+
+  // Fast path does a normal load global
+  {
+    Callable ic = CodeFactory::LoadGlobalICInOptimizedCode(
+        isolate_, function_id == Runtime::kLoadLookupSlotInsideTypeof
+                      ? INSIDE_TYPEOF
+                      : NOT_INSIDE_TYPEOF);
+    Node* result = BuildLoadGlobal(ic, context, feedback_slot, assembler);
+    __ SetAccumulator(result);
+    __ Dispatch();
+  }
+
+  // Slow path when we have to call out to the runtime
+  __ Bind(&slowpath);
+  {
+    Node* name = __ LoadConstantPoolEntry(name_index);
+    Node* result = __ CallRuntime(function_id, context, name);
+    __ SetAccumulator(result);
+    __ Dispatch();
+  }
+}
+
+// LdaLookupGlobalSlot <name_index> <feedback_slot> <depth>
+//
+// Lookup the object with the name in constant pool entry |name_index|
+// dynamically.
+void Interpreter::DoLdaLookupGlobalSlot(InterpreterAssembler* assembler) {
+  DoLdaLookupGlobalSlot(Runtime::kLoadLookupSlot, assembler);
+}
+
+// LdaLookupGlobalSlotInsideTypeof <name_index> <feedback_slot> <depth>
+//
+// Lookup the object with the name in constant pool entry |name_index|
+// dynamically without causing a NoReferenceError.
+void Interpreter::DoLdaLookupGlobalSlotInsideTypeof(
+    InterpreterAssembler* assembler) {
+  DoLdaLookupGlobalSlot(Runtime::kLoadLookupSlotInsideTypeof, assembler);
+}
+
 void Interpreter::DoStaLookupSlot(LanguageMode language_mode,
                                   InterpreterAssembler* assembler) {
   Node* value = __ GetAccumulator();