Fix typeof optimization for undetectable

src/compiler/effect-control-linearizer.cc

Index: src/compiler/effect-control-linearizer.cc
diff --git a/src/compiler/effect-control-linearizer.cc b/src/compiler/effect-control-linearizer.cc
index 1aa0ec6668c8ea5e228447ab3c3a082014acf9d5..7c4d16913213aa006d50f908c4530793bc2ee39f 100644
--- a/src/compiler/effect-control-linearizer.cc
+++ b/src/compiler/effect-control-linearizer.cc
@@ -738,6 +738,9 @@ bool EffectControlLinearizer::TryWireInStateEffect(Node* node,
     case IrOpcode::kObjectIsUndetectable:
       result = LowerObjectIsUndetectable(node);
       break;
+    case IrOpcode::kTypeOfIsFunction:
+      result = LowerObjectTypeOfIsFunction(node);
+      break;
     case IrOpcode::kNewRestParameterElements:
       result = LowerNewRestParameterElements(node);
       break;
@@ -1847,6 +1850,34 @@ Node* EffectControlLinearizer::LowerObjectIsUndetectable(Node* node) {
   return done.PhiAt(0);
 }
 
+Node* EffectControlLinearizer::LowerObjectTypeOfIsFunction(Node* node) {
+  Node* value = node->InputAt(0);
+
+  auto return_false = __ MakeDeferredLabel<3>();
+  auto done = __ MakeLabel<2>(MachineRepresentation::kBit);
+
+  Node* check0 = ObjectIsSmi(value);
+  __ GotoIf(check0, &return_false);
+
+  Node* value_map = __ LoadField(AccessBuilder::ForMap(), value);
+  Node* value_instance_type =
+      __ LoadField(AccessBuilder::ForMapInstanceType(), value_map);
+  Node* check1 = __ Uint32LessThanOrEqual(
+      __ Uint32Constant(FIRST_FUNCTION_TYPE), value_instance_type);
+  __ GotoUnless(check1, &return_false);
+  Node* check2 = __ Uint32LessThanOrEqual(
+      value_instance_type, __ Uint32Constant(LAST_FUNCTION_TYPE));
+  __ GotoUnless(check2, &return_false);

[vabr (Chromium), 2017/02/15 23:36:41]

This ignores proxies (which was helpfully pointed out by proxy-related tests). I
need to figure out how to include function proxies in this check.

[Benedikt Meurer, 2017/02/16 04:01:19]

The code of ObjectIsCallable is the correct code for typeof x==='function', it
just has a misleading name and the typing rule is wrong. So my idea to fix this
was to rename ObjectIsCallabe and fix the typing rule in the Typer.cc.

+
+  __ Goto(&done, __ Int32Constant(1));
+
+  __ Bind(&return_false);
+  __ Goto(&done, __ Int32Constant(0));
+
+  __ Bind(&done);
+  return done.PhiAt(0);
+}
+
 Node* EffectControlLinearizer::LowerNewRestParameterElements(Node* node) {
   int const formal_parameter_count = ParameterCountOf(node->op());