Introduce a hydrogen value for contexts, support context slot assignment.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index b7c1b78d1ba2075ec31e017c97f2268d2653dcb1..e8d21991f21d3e46e3b428cba902bc183831abcd 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -258,7 +258,15 @@ void LUnaryMathOperation::PrintDataTo(StringStream* stream) {
 
 
 void LLoadContextSlot::PrintDataTo(StringStream* stream) {
-  stream->Add("(%d, %d)", context_chain_length(), slot_index());
+  InputAt(0)->PrintTo(stream);
+  stream->Add("[%d]", slot_index());
+}
+
+
+void LStoreContextSlot::PrintDataTo(StringStream* stream) {
+  InputAt(0)->PrintTo(stream);
+  stream->Add("[%d] <- ", slot_index());
+  InputAt(1)->PrintTo(stream);
 }
 
 
@@ -1105,13 +1113,26 @@ LInstruction* LChunkBuilder::DoPushArgument(HPushArgument* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoContext(HContext* instr) {
+  return DefineAsRegister(new LContext);
+}
+
+
+LInstruction* LChunkBuilder::DoOuterContext(HOuterContext* instr) {
+  LOperand* context = UseRegisterAtStart(instr->value());
+  return DefineAsRegister(new LOuterContext(context));
+}
+
+
 LInstruction* LChunkBuilder::DoGlobalObject(HGlobalObject* instr) {
-  return DefineAsRegister(new LGlobalObject);
+  LOperand* context = UseRegisterAtStart(instr->value());
+  return DefineAsRegister(new LGlobalObject(context));
 }
 
 
 LInstruction* LChunkBuilder::DoGlobalReceiver(HGlobalReceiver* instr) {
-  return DefineAsRegister(new LGlobalReceiver);
+  LOperand* global_object = UseRegisterAtStart(instr->value());
+  return DefineAsRegister(new LGlobalReceiver(global_object));
 }
 
 
@@ -1621,7 +1642,22 @@ LInstruction* LChunkBuilder::DoStoreGlobal(HStoreGlobal* instr) {
 
 
 LInstruction* LChunkBuilder::DoLoadContextSlot(HLoadContextSlot* instr) {
-  return DefineAsRegister(new LLoadContextSlot);
+  LOperand* context = UseRegisterAtStart(instr->value());
+  return DefineAsRegister(new LLoadContextSlot(context));
+}
+
+
+LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
+  LOperand* context;
+  LOperand* value;
+  if (instr->NeedsWriteBarrier()) {
+    context = UseTempRegister(instr->context());
+    value = UseTempRegister(instr->value());
+  } else {
+    context = UseRegisterAtStart(instr->context());
+    value = UseRegister(instr->value());
+  }
+  return new LStoreContextSlot(context, value);
 }