[turbofan] Separate JSInliningHeuristic into own class.

This separates the core machinery and the heuristics involved with
inlining functions calls. So far the heuristic only respects our
%SetForceInlineFlag hint, but it will the place where general inlining
heuristics can live without impeding clarity of the core machinery.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1391903002

Cr-Commit-Position: refs/heads/master@{#31150}

BUILD.gn

@@ -761,6 +761,8 @@ source_set("v8_base") {
     "src/compiler/js-graph.h",
     "src/compiler/js-inlining.cc",
     "src/compiler/js-inlining.h",
+    "src/compiler/js-inlining-heuristic.cc",
+    "src/compiler/js-inlining-heuristic.h",
     "src/compiler/js-intrinsic-lowering.cc",
     "src/compiler/js-intrinsic-lowering.h",
     "src/compiler/js-operator.cc",

src/compiler/js-inlining-heuristic.cc

@@ -0,0 +1,34 @@
+// 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/js-inlining-heuristic.h"
+
+#include "src/compiler/node-matchers.h"
+#include "src/objects-inl.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+Reduction JSInliningHeuristic::Reduce(Node* node) {
+  if (node->opcode() != IrOpcode::kJSCallFunction) return NoChange();
+
+  Node* callee = node->InputAt(0);
+  HeapObjectMatcher match(callee);
+  if (!match.HasValue() || !match.Value()->IsJSFunction()) return NoChange();
+  Handle<JSFunction> function = Handle<JSFunction>::cast(match.Value());
+
+  // Functions marked with %SetForceInlineFlag are immediately inlined.
+  if (function->shared()->force_inline()) {
+    return inliner_.ReduceJSCallFunction(node, function);
+  }
+
+  // All other functions are only handled with general inlining.
+  if (mode_ == kRestrictedInlining) return NoChange();
+  return inliner_.ReduceJSCallFunction(node, function);
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8

src/compiler/js-inlining-heuristic.h

@@ -0,0 +1,34 @@
+// 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.
+
+#ifndef V8_COMPILER_JS_INLINING_HEURISTIC_H_
+#define V8_COMPILER_JS_INLINING_HEURISTIC_H_
+
+#include "src/compiler/js-inlining.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+class JSInliningHeuristic final : public AdvancedReducer {
+ public:
+  enum Mode { kRestrictedInlining, kGeneralInlining };
+  JSInliningHeuristic(Editor* editor, Mode mode, Zone* local_zone,
+                      CompilationInfo* info, JSGraph* jsgraph)
+      : AdvancedReducer(editor),
+        mode_(mode),
+        inliner_(editor, local_zone, info, jsgraph) {}
+
+  Reduction Reduce(Node* node) final;
+
+ private:
+  Mode const mode_;
+  JSInliner inliner_;
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_JS_INLINING_HEURISTIC_H_

src/compiler/js-inlining.cc

@@ -246,13 +246,17 @@ Reduction JSInliner::Reduce(Node* node) {
 
   JSCallFunctionAccessor call(node);
   HeapObjectMatcher match(call.jsfunction());
-  if (!match.HasValue()) return NoChange();
-
-  if (!match.Value()->IsJSFunction()) return NoChange();
+  if (!match.HasValue() || !match.Value()->IsJSFunction()) return NoChange();
   Handle<JSFunction> function = Handle<JSFunction>::cast(match.Value());
-  if (mode_ == kRestrictedInlining && !function->shared()->force_inline()) {
-    return NoChange();
-  }
+
+  return ReduceJSCallFunction(node, function);
+}
+
+
+Reduction JSInliner::ReduceJSCallFunction(Node* node,
+                                          Handle<JSFunction> function) {
+  DCHECK_EQ(IrOpcode::kJSCallFunction, node->opcode());
+  JSCallFunctionAccessor call(node);
 
   if (!function->shared()->IsInlineable()) {
     // Function must be inlineable.

src/compiler/js-inlining.h

@@ -19,22 +19,26 @@ namespace compiler {
 // Forward declarations.
 class JSCallFunctionAccessor;
 
+// The JSInliner provides the core graph inlining machinery. Note that this
+// class only deals with the mechanics of how to inline one graph into another,
+// heuristics that decide what and how much to inline are beyond its scope.
 class JSInliner final : public AdvancedReducer {
  public:
-  enum Mode { kRestrictedInlining, kGeneralInlining };
-
-  JSInliner(Editor* editor, Mode mode, Zone* local_zone, CompilationInfo* info,
+  JSInliner(Editor* editor, Zone* local_zone, CompilationInfo* info,
             JSGraph* jsgraph)
       : AdvancedReducer(editor),
-        mode_(mode),
         local_zone_(local_zone),
         info_(info),
         jsgraph_(jsgraph) {}
 
+  // Reducer interface, eagerly inlines everything.
   Reduction Reduce(Node* node) final;
 
+  // Can be used by inlining heuristics or by testing code directly, without
+  // using the above generic reducer interface of the inlining machinery.
+  Reduction ReduceJSCallFunction(Node* node, Handle<JSFunction> function);
+
  private:
-  Mode const mode_;
   Zone* local_zone_;
   CompilationInfo* info_;
   JSGraph* jsgraph_;

src/compiler/pipeline.cc

@@ -31,7 +31,7 @@
 #include "src/compiler/js-frame-specialization.h"
 #include "src/compiler/js-generic-lowering.h"
 #include "src/compiler/js-global-specialization.h"
-#include "src/compiler/js-inlining.h"
+#include "src/compiler/js-inlining-heuristic.h"
 #include "src/compiler/js-intrinsic-lowering.h"
 #include "src/compiler/js-type-feedback.h"
 #include "src/compiler/js-type-feedback-lowering.h"
@@ -526,10 +526,11 @@ struct InliningPhase {
             ? handle(data->info()->global_object())
             : Handle<GlobalObject>(),
         data->info()->dependencies());
-    JSInliner inliner(&graph_reducer, data->info()->is_inlining_enabled()
-                                          ? JSInliner::kGeneralInlining
-                                          : JSInliner::kRestrictedInlining,
-                      temp_zone, data->info(), data->jsgraph());
+    JSInliningHeuristic inlining(&graph_reducer,
+                                 data->info()->is_inlining_enabled()
+                                     ? JSInliningHeuristic::kGeneralInlining
+                                     : JSInliningHeuristic::kRestrictedInlining,
+                                 temp_zone, data->info(), data->jsgraph());
     AddReducer(data, &graph_reducer, &dead_code_elimination);
     AddReducer(data, &graph_reducer, &common_reducer);
     if (data->info()->is_frame_specializing()) {
@@ -539,7 +540,7 @@ struct InliningPhase {
       AddReducer(data, &graph_reducer, &global_specialization);
     }
     AddReducer(data, &graph_reducer, &context_specialization);
-    AddReducer(data, &graph_reducer, &inliner);
+    AddReducer(data, &graph_reducer, &inlining);
     graph_reducer.ReduceGraph();
   }
 };

tools/gyp/v8.gyp

@@ -526,6 +526,8 @@
         '../../src/compiler/js-graph.h',
         '../../src/compiler/js-inlining.cc',
         '../../src/compiler/js-inlining.h',
+        '../../src/compiler/js-inlining-heuristic.cc',
+        '../../src/compiler/js-inlining-heuristic.h',
         '../../src/compiler/js-intrinsic-lowering.cc',
         '../../src/compiler/js-intrinsic-lowering.h',
         '../../src/compiler/js-operator.cc',