[Interpreter] Implement ForIn in bytecode graph builder.

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 157a21d03bf1cf7fc220d536f55e20807a4a5b01..b0ad5fe306832f1f5f3d82ce04e8394c81b5240f 100644
--- a/src/compiler/bytecode-graph-builder.cc
+++ b/src/compiler/bytecode-graph-builder.cc
@@ -1018,7 +1018,6 @@ void BytecodeGraphBuilder::BuildBinaryOp(
   Node* left = environment()->LookupRegister(iterator.GetRegisterOperand(0));
   Node* right = environment()->LookupAccumulator();
   Node* node = NewNode(js_op, left, right);
-
   AddEmptyFrameStateInputs(node);
   environment()->BindAccumulator(node);
 }
@@ -1261,12 +1260,6 @@ void BytecodeGraphBuilder::VisitToNumber(
 }
 
 
-void BytecodeGraphBuilder::VisitToObject(
-    const interpreter::BytecodeArrayIterator& iterator) {
-  BuildCastOperator(javascript()->ToObject(), iterator);
-}
-
-
 void BytecodeGraphBuilder::VisitJump(
     const interpreter::BytecodeArrayIterator& iterator) {
   BuildJump();
@@ -1374,19 +1367,56 @@ void BytecodeGraphBuilder::VisitReturn(
 
 void BytecodeGraphBuilder::VisitForInPrepare(
     const interpreter::BytecodeArrayIterator& iterator) {
-  UNIMPLEMENTED();
+  // Bytecode generator only reaches here if the object is not null or
+  // undefined, whereas ast-graph-builder has to check.
+  Node* object = environment()->LookupAccumulator();
+  Node* receiver = NewNode(javascript()->ToObject(), object);
+  AddEmptyFrameStateInputs(receiver);
+  Node* prepare = NewNode(javascript()->ForInPrepare(), receiver);
+  AddEmptyFrameStateInputs(prepare);

[rmcilroy, 2015/12/17 15:43:26]

Hmm, this is a bit troubling for deopt - you have two sets of frame states,
which presumably means there are two potential deopt points within the same
bytecode. Not sure if that would work - I think we still need to ToObject as a
separate bytecode (sorry...).

[oth, 2015/12/17 19:28:23]

NP. Will re-spin shortly. The interpreter needs a wrapper around
Runtime_ToObject as the latter can throw.

+  Node* cache_type = NewNode(common()->Projection(0), prepare);
+  Node* cache_array = NewNode(common()->Projection(1), prepare);
+  Node* cache_length = NewNode(common()->Projection(2), prepare);
+  environment()->BindRegister(iterator.GetRegisterOperand(0), receiver);
+  environment()->BindRegister(iterator.GetRegisterOperand(1), cache_type);
+  environment()->BindRegister(iterator.GetRegisterOperand(2), cache_array);
+  environment()->BindRegister(iterator.GetRegisterOperand(3), cache_length);
+}
+
+
+void BytecodeGraphBuilder::VisitForInDone(
+    const interpreter::BytecodeArrayIterator& iterator) {
+  Node* index = environment()->LookupRegister(iterator.GetRegisterOperand(0));
+  Node* cache_length =
+      environment()->LookupRegister(iterator.GetRegisterOperand(1));
+  Node* exit_cond = NewNode(javascript()->ForInDone(), index, cache_length);
+  AddEmptyFrameStateInputs(exit_cond);
+  environment()->BindAccumulator(exit_cond);
 }
 
 
 void BytecodeGraphBuilder::VisitForInNext(
     const interpreter::BytecodeArrayIterator& iterator) {
-  UNIMPLEMENTED();
+  Node* receiver =
+      environment()->LookupRegister(iterator.GetRegisterOperand(0));
+  Node* cache_type =
+      environment()->LookupRegister(iterator.GetRegisterOperand(1));
+  Node* cache_array =
+      environment()->LookupRegister(iterator.GetRegisterOperand(2));
+  Node* index = environment()->LookupRegister(iterator.GetRegisterOperand(3));
+  Node* value = NewNode(javascript()->ForInNext(), receiver, cache_array,
+                        cache_type, index);
+  AddEmptyFrameStateInputs(value);
+  environment()->BindAccumulator(value);
 }
 
 
-void BytecodeGraphBuilder::VisitForInDone(
+void BytecodeGraphBuilder::VisitForInStep(
     const interpreter::BytecodeArrayIterator& iterator) {
-  UNIMPLEMENTED();
+  Node* index = environment()->LookupRegister(iterator.GetRegisterOperand(0));
+  index = NewNode(javascript()->ForInStep(), index);
+  AddEmptyFrameStateInputs(index);
+  environment()->BindRegister(iterator.GetRegisterOperand(0), index);
 }