[turbofan] Avoid unnecessary copying of nodes during inlining.

src/compiler/ast-graph-builder.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/ast-graph-builder.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
@@ skipping 398 matching lines @@
   TryFinallyBuilder* control_;
 };
 
 
 // Helper for generating before and after frame states.
 class AstGraphBuilder::FrameStateBeforeAndAfter {
  public:
   FrameStateBeforeAndAfter(AstGraphBuilder* builder, BailoutId id_before)
       : builder_(builder), frame_state_before_(nullptr) {
     frame_state_before_ = id_before == BailoutId::None()
-                              ? builder_->jsgraph()->EmptyFrameState()
+                              ? builder_->GetEmptyFrameState()
                               : builder_->environment()->Checkpoint(id_before);
   }
 
   void AddToNode(
       Node* node, BailoutId id_after,
       OutputFrameStateCombine combine = OutputFrameStateCombine::Ignore()) {
     int count = OperatorProperties::GetFrameStateInputCount(node->op());
     DCHECK_LE(count, 2);
 
     if (count >= 1) {
       // Add the frame state for after the operation.
       DCHECK_EQ(IrOpcode::kDead,
                 NodeProperties::GetFrameStateInput(node, 0)->opcode());
 
       bool node_has_exception = NodeProperties::IsExceptionalCall(node);
 
       Node* frame_state_after =
           id_after == BailoutId::None()
-              ? builder_->jsgraph()->EmptyFrameState()
+              ? builder_->GetEmptyFrameState()
               : builder_->environment()->Checkpoint(id_after, combine,
                                                     node_has_exception);
 
       NodeProperties::ReplaceFrameStateInput(node, 0, frame_state_after);
     }
 
     if (count >= 2) {
       // Add the frame state for before the operation.
       DCHECK_EQ(IrOpcode::kDead,
                 NodeProperties::GetFrameStateInput(node, 1)->opcode());
@@ skipping 83 matching lines @@
   if (!new_target_.is_set()) {
     int params = info()->num_parameters_including_this();
     int index = Linkage::GetJSCallNewTargetParamIndex(params);
     const Operator* op = common()->Parameter(index, "%new.target");
     Node* node = NewNode(op, graph()->start());
     new_target_.set(node);
   }
   return new_target_.get();
 }
 
+Node* AstGraphBuilder::GetEmptyFrameState() {
+  if (!empty_frame_state_.is_set()) {
+    const Operator* op = common()->FrameState(
+        BailoutId::None(), OutputFrameStateCombine::Ignore(), nullptr);
+    Node* node = graph()->NewNode(
+        op, jsgraph()->EmptyStateValues(), jsgraph()->EmptyStateValues(),
+        jsgraph()->EmptyStateValues(), jsgraph()->NoContextConstant(),
+        jsgraph()->UndefinedConstant(), graph()->start());
+    empty_frame_state_.set(node);
+  }
+  return empty_frame_state_.get();
+}
 
 bool AstGraphBuilder::CreateGraph(bool stack_check) {
   Scope* scope = info()->scope();
   DCHECK_NOT_NULL(graph());
 
   // Set up the basic structure of the graph. Outputs for {Start} are the formal
   // parameters (including the receiver) plus new target, number of arguments,
   // context and closure.
   int actual_parameter_count = info()->num_parameters_including_this() + 4;
   graph()->SetStart(graph()->NewNode(common()->Start(actual_parameter_count)));
@@ skipping 316 matching lines @@
     Node** state_values, int offset, int count) {
   Node** env_values = (count == 0) ? nullptr : &values()->at(offset);
   *state_values = builder_->state_values_cache_.GetNodeForValues(
       env_values, static_cast<size_t>(count));
 }
 
 Node* AstGraphBuilder::Environment::Checkpoint(BailoutId ast_id,
                                                OutputFrameStateCombine combine,
                                                bool owner_has_exception) {
   if (!builder()->info()->is_deoptimization_enabled()) {
-    return builder()->jsgraph()->EmptyFrameState();
+    return builder()->GetEmptyFrameState();
   }
 
   UpdateStateValues(&parameters_node_, 0, parameters_count());
   UpdateStateValuesWithCache(&locals_node_, parameters_count(), locals_count());
   UpdateStateValues(&stack_node_, parameters_count() + locals_count(),
                     stack_height());
 
   const Operator* op = common()->FrameState(
       ast_id, combine, builder()->frame_state_function_info());
 
@@ skipping 3469 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8