[Interpreter] Implement ForIn in bytecode graph builder.

src/compiler/bytecode-graph-builder.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/bytecode-graph-builder.h"
 
 #include "src/compiler/bytecode-branch-analysis.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/operator-properties.h"
 #include "src/interpreter/bytecodes.h"
@@ skipping 1000 matching lines @@
   UpdateControlDependencyToLeaveFunction(control);
   environment()->BindAccumulator(value);
 }
 
 
 void BytecodeGraphBuilder::BuildBinaryOp(
     const Operator* js_op, const interpreter::BytecodeArrayIterator& iterator) {
   Node* left = environment()->LookupRegister(iterator.GetRegisterOperand(0));
   Node* right = environment()->LookupAccumulator();
   Node* node = NewNode(js_op, left, right);
-
   AddEmptyFrameStateInputs(node);
   environment()->BindAccumulator(node);
 }
 
 
 void BytecodeGraphBuilder::VisitAdd(
     const interpreter::BytecodeArrayIterator& iterator) {
   BinaryOperationHints hints = BinaryOperationHints::Any();
   BuildBinaryOp(javascript()->Add(language_mode(), hints), iterator);
 }
@@ skipping 222 matching lines @@
   BuildCastOperator(javascript()->ToName(), iterator);
 }
 
 
 void BytecodeGraphBuilder::VisitToNumber(
     const interpreter::BytecodeArrayIterator& iterator) {
   BuildCastOperator(javascript()->ToNumber(), iterator);
 }
 
 
-void BytecodeGraphBuilder::VisitToObject(
-    const interpreter::BytecodeArrayIterator& iterator) {
-  BuildCastOperator(javascript()->ToObject(), iterator);
-}
-
-
 void BytecodeGraphBuilder::VisitJump(
     const interpreter::BytecodeArrayIterator& iterator) {
   BuildJump();
 }
 
 
 void BytecodeGraphBuilder::VisitJumpConstant(
     const interpreter::BytecodeArrayIterator& iterator) {
   BuildJump();
 }
@@ skipping 87 matching lines @@
     const interpreter::BytecodeArrayIterator& iterator) {
   Node* control =
       NewNode(common()->Return(), environment()->LookupAccumulator());
   UpdateControlDependencyToLeaveFunction(control);
   set_environment(nullptr);
 }
 
 
 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);
 }
 
 
 void BytecodeGraphBuilder::MergeEnvironmentsOfBackwardBranches(
     int source_offset, int target_offset) {
   DCHECK_GE(source_offset, target_offset);
   const ZoneVector<int>* branch_sites =
       branch_analysis()->BackwardBranchesTargetting(target_offset);
   if (branch_sites->back() == source_offset) {
     // The set of back branches is complete, merge them.
@@ skipping 232 matching lines @@
 
 void BytecodeGraphBuilder::UpdateControlDependencyToLeaveFunction(Node* exit) {
   if (environment()->IsMarkedAsUnreachable()) return;
   environment()->MarkAsUnreachable();
   exit_controls_.push_back(exit);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8