[turbofan] Sparse representation for state values

src/compiler/instruction-selector.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/instruction-selector.h"
 
 #include <limits>
 
 #include "src/base/adapters.h"
 #include "src/compiler/compiler-source-position-table.h"
@@ skipping 462 matching lines @@
 
  private:
   ZoneVector<Node*> objects_;
 };
 
 // Returns the number of instruction operands added to inputs.
 size_t InstructionSelector::AddOperandToStateValueDescriptor(
     StateValueList* values, InstructionOperandVector* inputs,
     OperandGenerator* g, StateObjectDeduplicator* deduplicator, Node* input,
     MachineType type, FrameStateInputKind kind, Zone* zone) {
+  if (input == nullptr) {
+    values->PushOptimizedOut();
+    return 0;
+  }
+
   switch (input->opcode()) {
     case IrOpcode::kObjectState: {
       UNREACHABLE();
       return 0;
     }
     case IrOpcode::kTypedObjectState: {
       size_t id = deduplicator->GetObjectId(input);
       if (id == StateObjectDeduplicator::kNotDuplicated) {
         size_t entries = 0;
         id = deduplicator->InsertObject(input);
         StateValueList* nested = values->PushRecursiveField(zone, id);
         int const input_count = input->op()->ValueInputCount();
         ZoneVector<MachineType> const* types = MachineTypesOf(input->op());
         for (int i = 0; i < input_count; ++i) {
           entries += AddOperandToStateValueDescriptor(
               nested, inputs, g, deduplicator, input->InputAt(i), types->at(i),
               kind, zone);
         }
         return entries;
       } else {
         // Crankshaft counts duplicate objects for the running id, so we have
         // to push the input again.
         deduplicator->InsertObject(input);
         values->PushDuplicate(id);
         return 0;
       }
     }
     default: {
       Heap* const heap = isolate()->heap();
       if (input->opcode() == IrOpcode::kHeapConstant) {

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

Maybe we can remove this ugly dance will now?

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

Not yet, I don't think, there still could be optimized_out nodes coming from
AstGraphBuilder.

         Handle<HeapObject> constant = OpParameter<Handle<HeapObject>>(input);
         Heap::RootListIndex root_index;
         if (heap->IsRootHandle(constant, &root_index) &&
             root_index == Heap::kOptimizedOutRootIndex) {
           values->PushOptimizedOut();
           return 0;
         }
       }
       inputs->push_back(OperandForDeopt(g, input, kind, type.representation()));
       values->PushPlain(type);
@@ skipping 1587 matching lines @@
   return new (instruction_zone()) FrameStateDescriptor(
       instruction_zone(), state_info.type(), state_info.bailout_id(),
       state_info.state_combine(), parameters, locals, stack,
       state_info.shared_info(), outer_state);
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8