[turbofan] Make context specialization into a reducer.

src/compiler/js-context-specialization.cc

Index: src/compiler/js-context-specialization.cc
diff --git a/src/compiler/js-context-specialization.cc b/src/compiler/js-context-specialization.cc
index d11bc6671188e5a6de74ee678fc02f48e46b069b..4545343d1430d8f71f14c8f3319b2ac9b526b9dc 100644
--- a/src/compiler/js-context-specialization.cc
+++ b/src/compiler/js-context-specialization.cc
@@ -6,7 +6,6 @@
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/js-context-specialization.h"
 #include "src/compiler/js-operator.h"
-#include "src/compiler/node-aux-data-inl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties-inl.h"
 
@@ -14,45 +13,20 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
-class ContextSpecializationVisitor : public NullNodeVisitor {
- public:
-  explicit ContextSpecializationVisitor(JSContextSpecializer* spec)
-      : spec_(spec) {}
-
-  void Post(Node* node) {
-    switch (node->opcode()) {
-      case IrOpcode::kJSLoadContext: {
-        Reduction r = spec_->ReduceJSLoadContext(node);
-        if (r.Changed() && r.replacement() != node) {
-          NodeProperties::ReplaceWithValue(node, r.replacement());
-          node->RemoveAllInputs();
-        }
-        break;
-      }
-      case IrOpcode::kJSStoreContext: {
-        Reduction r = spec_->ReduceJSStoreContext(node);
-        if (r.Changed() && r.replacement() != node) {
-          NodeProperties::ReplaceWithValue(node, r.replacement());
-          node->RemoveAllInputs();
-        }
-        break;
-      }
-      default:
-        break;
-    }
-  }
-
- private:
-  JSContextSpecializer* spec_;
-};
-
 
-void JSContextSpecializer::SpecializeToContext() {
-  NodeProperties::ReplaceWithValue(context_,
-                                   jsgraph_->Constant(info_->context()));
-
-  ContextSpecializationVisitor visitor(this);
-  jsgraph_->graph()->VisitNodeInputsFromEnd(&visitor);
+Reduction JSContextSpecializer::Reduce(Node* node) {
+  if (node == context_) {
+    Node* constant = jsgraph_->Constant(info_->context());
+    NodeProperties::ReplaceWithValue(node, constant);
+    return Replace(constant);
+  }
+  if (node->opcode() == IrOpcode::kJSLoadContext) {
+    return ReduceJSLoadContext(node);
+  }
+  if (node->opcode() == IrOpcode::kJSStoreContext) {
+    return ReduceJSStoreContext(node);
+  }
+  return NoChange();
 }
 
 
@@ -100,7 +74,9 @@ Reduction JSContextSpecializer::ReduceJSLoadContext(Node* node) {
   // Success. The context load can be replaced with the constant.
   // TODO(titzer): record the specialization for sharing code across multiple
   // contexts that have the same value in the corresponding context slot.
-  return Reducer::Replace(jsgraph_->Constant(value));
+  Node* constant = jsgraph_->Constant(value);
+  NodeProperties::ReplaceWithValue(node, constant);
+  return Reducer::Replace(constant);

[Benedikt Meurer, 2014/12/01 17:51:57]

Remove Reducer:: prefix.

 }