[turbofan] Make context specialization into a reducer.

test/cctest/compiler/test-js-context-specialization.cc

 // Copyright 2014 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/js-context-specialization.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/source-position.h"
 #include "test/cctest/cctest.h"
@@ skipping 185 matching lines @@
   Handle<Object> expected = t.factory()->InternalizeUtf8String("gboy!");
   const int slot = Context::GLOBAL_OBJECT_INDEX;
   native->set(slot, *expected);
   t.info()->SetContext(native);
 
   Node* const_context = t.jsgraph()->Constant(native);
   Node* param_context = t.NewNode(t.common()->Parameter(0), start);
   JSContextSpecializer spec(t.info(), t.jsgraph(), const_context);
 
   {
-    // Check that SpecializeToContext() replaces values and forwards effects
+    // Check that specialization replaces values and forwards effects
     // correctly, and folds values from constant and non-constant contexts
     Node* effect_in = start;
     Node* load = t.NewNode(t.javascript()->LoadContext(0, slot, true),
                            const_context, const_context, effect_in);
 
 
     Node* value_use = t.NewNode(t.simplified()->ChangeTaggedToInt32(), load);
     Node* other_load = t.NewNode(t.javascript()->LoadContext(0, slot, true),
                                  param_context, param_context, load);
     Node* effect_use = other_load;
     Node* other_use =
         t.NewNode(t.simplified()->ChangeTaggedToInt32(), other_load);
 
     Node* add = t.NewNode(t.javascript()->Add(), value_use, other_use,
                           param_context, other_load, start);
 
     Node* ret = t.NewNode(t.common()->Return(), add, effect_use, start);
     Node* end = t.NewNode(t.common()->End(), ret);
     USE(end);
     t.graph()->SetEnd(end);
 
     // Double check the above graph is what we expect, or the test is broken.
     CheckEffectInput(effect_in, load);
     CheckEffectInput(load, effect_use);
 
-    // Perform the substitution on the entire graph.
-    spec.SpecializeToContext();
+    // Perform the reduction on the entire graph.
+    GraphReducer graph_reducer(t.graph(), t.main_zone());
+    graph_reducer.AddReducer(&spec);
+    graph_reducer.ReduceGraph();
 
     // Effects should have been forwarded (not replaced with a value).
     CheckEffectInput(effect_in, effect_use);
 
     // Use of {other_load} should not have been replaced.
     CHECK_EQ(other_load, other_use->InputAt(0));
 
     Node* replacement = value_use->InputAt(0);
     HeapObjectMatcher<Object> match(replacement);
     CHECK(match.HasValue());
@@ skipping 51 matching lines @@
   {
     FunctionTester T(
         "(function() { if (false) { var x = 1; } function inc(a)"
         " { return a + x; } return inc; })()");  // x is undefined!
 
     CHECK(T.Call(T.Val(0.0), T.Val(0.0)).ToHandleChecked()->IsNaN());
     CHECK(T.Call(T.Val(2.0), T.Val(0.0)).ToHandleChecked()->IsNaN());
     CHECK(T.Call(T.Val(-2.1), T.Val(0.0)).ToHandleChecked()->IsNaN());
   }
 }