Reapply "Initial implementation of on-stack replacement (OSR)."

runtime/vm/flow_graph_builder.h

 // Copyright (c) 2012, 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_BUILDER_H_
 #define VM_FLOW_GRAPH_BUILDER_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 82 matching lines @@
 
   FlowGraph* caller_graph_;
   Definition* call_;
   GrowableArray<Data> exits_;
 };
 
 
 // Build a flow graph from a parsed function's AST.
 class FlowGraphBuilder: public ValueObject {
  public:
-  // The inlining context is NULL if not inlining.
+  // The inlining context is NULL if not inlining.  The osr_id is the deopt
+  // id of the OSR entry or Isolate::kNoDeoptId if not compiling for OSR.
   FlowGraphBuilder(ParsedFunction* parsed_function,
                    const Array& ic_data_array,
-                   InlineExitCollector* exit_collector);
+                   InlineExitCollector* exit_collector,
+                   intptr_t osr_id);
 
   FlowGraph* BuildGraph();
 
   ParsedFunction* parsed_function() const { return parsed_function_; }
   const Array& ic_data_array() const { return ic_data_array_; }
 
   void Bailout(const char* reason);
 
   intptr_t AllocateBlockId() { return ++last_used_block_id_; }
   void SetInitialBlockId(intptr_t id) { last_used_block_id_ = id; }
@@ skipping 19 matching lines @@
   intptr_t num_stack_locals() const {
     return num_stack_locals_;
   }
 
   bool IsInlining() const { return (exit_collector_ != NULL); }
   InlineExitCollector* exit_collector() const { return exit_collector_; }
 
   intptr_t args_pushed() const { return args_pushed_; }
   void add_args_pushed(intptr_t n) { args_pushed_ += n; }
 
+  // When compiling for OSR, remove blocks that are not reachable from the
+  // OSR entry point.
+  void PruneUnreachable();
+
  private:
   intptr_t parameter_count() const {
     return num_copied_params_ + num_non_copied_params_;
   }
   intptr_t variable_count() const {
     return parameter_count() + num_stack_locals_;
   }
 
   ParsedFunction* parsed_function_;
   const Array& ic_data_array_;
 
   const intptr_t num_copied_params_;
   const intptr_t num_non_copied_params_;
   const intptr_t num_stack_locals_;  // Does not include any parameters.
   InlineExitCollector* const exit_collector_;
 
   intptr_t last_used_block_id_;
   intptr_t context_level_;
   intptr_t last_used_try_index_;
   intptr_t try_index_;
   GraphEntryInstr* graph_entry_;
 
   // Outgoing argument stack height.
   intptr_t args_pushed_;
 
+  // The deopt id of the OSR entry or Isolate::kNoDeoptId if not compiling
+  // for OSR.
+  const intptr_t osr_id_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(FlowGraphBuilder);
 };
 
 
 class TestGraphVisitor;
 
 // Translate an AstNode to a control-flow graph fragment for its effects
 // (e.g., a statement or an expression in an effect context).  Implements a
 // function from an AstNode and next temporary index to a graph fragment
 // with a single entry and at most one exit.  The fragment is represented by
@@ skipping 41 matching lines @@
 
   // Append a 'diamond' branch and join to this graph, depending on which
   // parts are reachable.  Assumes this graph is open.
   void Join(const TestGraphVisitor& test_fragment,
             const EffectGraphVisitor& true_fragment,
             const EffectGraphVisitor& false_fragment);
 
   // Append a 'while loop' test and back edge to this graph, depending on
   // which parts are reachable.  Afterward, the graph exit is the false
   // successor of the loop condition.
-  void TieLoop(const TestGraphVisitor& test_fragment,
+  void TieLoop(intptr_t token_pos,
+               const TestGraphVisitor& test_fragment,
                const EffectGraphVisitor& body_fragment);
 
   // Wraps a value in a push-argument instruction and adds the result to the
   // graph.
   PushArgumentInstr* PushArgument(Value* value);
 
   // This implementation shares state among visitors by using the builder.
   // The implementation is incorrect if a visitor that hits a return is not
   // actually added to the graph.
   void AddReturnExit(intptr_t token_pos, Value* value);
@@ skipping 258 matching lines @@
   // Output parameters.
   GrowableArray<TargetEntryInstr**> true_successor_addresses_;
   GrowableArray<TargetEntryInstr**> false_successor_addresses_;
 
   intptr_t condition_token_pos_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_BUILDER_H_