Introduce simple Thread class to support gradual refactoring of interfaces.

runtime/vm/flow_graph.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_FLOW_GRAPH_H_
 #define VM_FLOW_GRAPH_H_
 
 #include "vm/bit_vector.h"
 #include "vm/growable_array.h"
 #include "vm/hash_map.h"
 #include "vm/intermediate_language.h"
 #include "vm/parser.h"
+#include "vm/thread.h"
 
 namespace dart {
 
 class BlockEffects;
 class FlowGraphBuilder;
 class ValueInliningContext;
 class VariableLivenessAnalysis;
 
 class BlockIterator : public ValueObject {
  public:
@@ skipping 119 matching lines @@
 
   intptr_t current_ssa_temp_index() const { return current_ssa_temp_index_; }
   void set_current_ssa_temp_index(intptr_t index) {
     current_ssa_temp_index_ = index;
   }
 
   intptr_t max_virtual_register_number() const {
     return current_ssa_temp_index();
   }
 
-  Isolate* isolate() const { return isolate_; }
+  Thread* thread() const { return thread_; }
+  Zone* zone() const { return thread()->zone(); }
+  Isolate* isolate() const { return thread()->isolate(); }
 
   intptr_t max_block_id() const { return max_block_id_; }
   void set_max_block_id(intptr_t id) { max_block_id_ = id; }
   intptr_t allocate_block_id() { return ++max_block_id_; }
 
   GraphEntryInstr* graph_entry() const {
     return graph_entry_;
   }
 
   ConstantInstr* constant_null() const {
@@ skipping 155 matching lines @@
   void ReplacePredecessor(BlockEntryInstr* old_block,
                           BlockEntryInstr* new_block);
 
   // Find the natural loop for the back edge m->n and attach loop
   // information to block n (loop header). The algorithm is described in
   // "Advanced Compiler Design & Implementation" (Muchnick) p192.
   // Returns a BitVector indexed by block pre-order number where each bit
   // indicates membership in the loop.
   BitVector* FindLoop(BlockEntryInstr* m, BlockEntryInstr* n) const;
 
-  Isolate* isolate_;
+  Thread* thread_;
 
   // DiscoverBlocks computes parent_ and assigned_vars_ which are then used
   // if/when computing SSA.
   GrowableArray<intptr_t> parent_;
   GrowableArray<BitVector*> assigned_vars_;
 
   intptr_t current_ssa_temp_index_;
   intptr_t max_block_id_;
 
   // Flow graph fields.
@@ skipping 65 matching lines @@
   // Update live-in set for the given block: live-in should contain
   // all values that are live-out from the block and are not defined
   // by this block.
   // Returns true if live-in set was changed.
   bool UpdateLiveIn(const BlockEntryInstr& instr);
 
   // Perform fix-point iteration updating live-out and live-in sets
   // for blocks until they stop changing.
   void ComputeLiveInAndLiveOutSets();
 
-  Isolate* isolate() const { return isolate_; }
+  Zone* zone() const { return zone_; }
 
-  Isolate* isolate_;
+  Zone* zone_;
 
   const intptr_t variable_count_;
 
   const GrowableArray<BlockEntryInstr*>& postorder_;
 
   // Live-out sets for each block.  They contain indices of variables
   // that are live out from this block: that is values that were either
   // defined in this block or live into it and that are used in some
   // successor block.
   GrowableArray<BitVector*> live_out_;
@@ skipping 35 matching lines @@
   GrowableArray<BitVector*> available_at_;
 };
 
 
 class DefinitionWorklist : public ValueObject {
  public:
   DefinitionWorklist(FlowGraph* flow_graph,
                      intptr_t initial_capacity)
       : defs_(initial_capacity),
         contains_vector_(
-            new BitVector(flow_graph->isolate(),
+            new BitVector(flow_graph->zone(),
                           flow_graph->current_ssa_temp_index())) {
   }
 
   void Add(Definition* defn) {
     if (!Contains(defn)) {
       defs_.Add(defn);
       contains_vector_->Add(defn->ssa_temp_index());
     }
   }
 
@@ skipping 22 matching lines @@
 
  private:
   GrowableArray<Definition*> defs_;
   BitVector* contains_vector_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_H_