[turbofan] Sparse representation for state values

src/compiler/liveness-analyzer.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/base/adapters.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/liveness-analyzer.h"
 #include "src/compiler/node.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/state-values-utils.h"
@@ skipping 131 matching lines @@
       break;
     }
   }
 
   if (has_accumulator_) {
     DCHECK_EQ(frame_state->InputAt(2)->opcode(), IrOpcode::kStateValues);
     DCHECK_EQ(
         static_cast<int>(StateValuesAccess(frame_state->InputAt(2)).size()), 1);
     int index = liveness->length() - 1;
     if (!liveness->Contains(index) && !permanently_live_.Contains(index)) {
-      Node* new_value =
-          state_values_cache()->GetNodeForValues(&replacement_node_, 1);
+      Node* new_value = state_values_cache()->GetNodeForValues(
+          &replacement_node_, 1, nullptr);

[Jarin, 2016/12/07 08:56:20]

How about adding a default value (nullptr) for the liveness? This nullptr here
is a bit confusing.

[Leszek Swirski, 2016/12/08 15:44:30]

Ah, I had that originally but forgot to add it back in after some refactoring.
Done.

       frame_state->ReplaceInput(2, new_value);
     }
   }
 }
 
 
 Node* NonLiveFrameStateSlotReplacer::ClearNonLiveStateValues(
     Node* values, BitVector* liveness) {
   DCHECK(inputs_buffer_.empty());
 
   int var = 0;
   for (Node* value_node : values->inputs()) {
     // Make sure this isn't a state value tree
     DCHECK(value_node->opcode() != IrOpcode::kStateValues);
 
     // Index of the next variable is its furure index in the inputs buffer,
     // i.e., the buffer's size.
     bool live = liveness->Contains(var) || permanently_live_.Contains(var);
     inputs_buffer_.push_back(live ? value_node : replacement_node_);
 
     var++;
   }
 
   Node* result = state_values_cache()->GetNodeForValues(
       inputs_buffer_.empty() ? nullptr : &(inputs_buffer_.front()),
-      inputs_buffer_.size());
+      inputs_buffer_.size(), nullptr);
   inputs_buffer_.clear();
   return result;
 }
 
 
 void LivenessAnalyzerBlock::Print(std::ostream& os) {
   os << "Block " << id();
   bool first = true;
   for (LivenessAnalyzerBlock* pred : predecessors_) {
     if (!first) {
@@ skipping 34 matching lines @@
     for (int i = 0; i < live_.length(); i++) {
       os << (live_.Contains(i) ? "L" : ".");
     }
     os << std::endl;
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8