[Interpreter] Bytecodes for exchanging registers.

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 146 matching lines @@
 
 
 void BytecodeGraphBuilder::Environment::BindAccumulator(
     Node* node, FrameStateBeforeAndAfter* states) {
   if (states) {
     states->AddToNode(node, AccumulatorUpdateMode::kOutputInAccumulator);
   }
   values()->at(accumulator_base_) = node;
 }
 
+
 void BytecodeGraphBuilder::Environment::RecordAfterState(
     Node* node, FrameStateBeforeAndAfter* states) {
   states->AddToNode(node, AccumulatorUpdateMode::kOutputIgnored);
 }
 
 
+void BytecodeGraphBuilder::Environment::ExchangeRegisters(
+    interpreter::Register r0, interpreter::Register r1) {

[rmcilroy, 2016/01/04 11:54:53]

nit - reg0, reg1

[oth, 2016/01/04 14:01:42]

Done.

+  int i0 = RegisterToValuesIndex(r0);

[rmcilroy, 2016/01/04 11:54:53]

nit - reg0_index

[oth, 2016/01/04 14:01:42]

Done.

+  int i1 = RegisterToValuesIndex(r1);
+  Node* saved = values()->at(i0);
+  values()->at(i0) = values()->at(i1);
+  values()->at(i1) = saved;
+}
+
+
 Node* BytecodeGraphBuilder::Environment::LookupAccumulator() const {
   return values()->at(accumulator_base_);
 }
 
 
 bool BytecodeGraphBuilder::Environment::IsMarkedAsUnreachable() const {
   return GetControlDependency()->opcode() == IrOpcode::kDead;
 }
 
 
@@ skipping 371 matching lines @@
 }
 
 
 void BytecodeGraphBuilder::VisitMov(
     const interpreter::BytecodeArrayIterator& iterator) {
   Node* value = environment()->LookupRegister(iterator.GetRegisterOperand(0));
   environment()->BindRegister(iterator.GetRegisterOperand(1), value);
 }
 
 
+void BytecodeGraphBuilder::VisitExchange(
+    const interpreter::BytecodeArrayIterator& iterator) {
+  environment()->ExchangeRegisters(iterator.GetRegisterOperand(0),
+                                   iterator.GetRegisterOperand(1));
+}
+
+
+void BytecodeGraphBuilder::VisitExchangeWide(
+    const interpreter::BytecodeArrayIterator& iterator) {
+  environment()->ExchangeRegisters(iterator.GetRegisterOperand(0),
+                                   iterator.GetRegisterOperand(1));
+}
+
+
 void BytecodeGraphBuilder::BuildLoadGlobal(
     const interpreter::BytecodeArrayIterator& iterator,
     TypeofMode typeof_mode) {
   FrameStateBeforeAndAfter states(this, iterator);
   Handle<Name> name =
       Handle<Name>::cast(iterator.GetConstantForIndexOperand(0));
   VectorSlotPair feedback = CreateVectorSlotPair(iterator.GetIndexOperand(1));
 
   const Operator* op = javascript()->LoadGlobal(name, feedback, typeof_mode);
   Node* node = NewNode(op, BuildLoadFeedbackVector());
@@ skipping 1253 matching lines @@
 
 void BytecodeGraphBuilder::UpdateControlDependencyToLeaveFunction(Node* exit) {
   if (environment()->IsMarkedAsUnreachable()) return;
   environment()->MarkAsUnreachable();
   exit_controls_.push_back(exit);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8