Remember deopt-id -> context-level mappings in var descriptors.

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 RUNTIME_VM_FLOW_GRAPH_BUILDER_H_
 #define RUNTIME_VM_FLOW_GRAPH_BUILDER_H_
 
 #include "platform/assert.h"
 #include "platform/globals.h"
 #include "vm/allocation.h"
@@ skipping 80 matching lines @@
 };
 
 
 // Build a flow graph from a parsed function's AST.
 class FlowGraphBuilder : public ValueObject {
  public:
   // The inlining context is NULL if not inlining.  The osr_id is the deopt
   // id of the OSR entry or Compiler::kNoOSRDeoptId if not compiling for OSR.
   FlowGraphBuilder(const ParsedFunction& parsed_function,
                    const ZoneGrowableArray<const ICData*>& ic_data_array,
+                   ZoneGrowableArray<intptr_t>* context_level_array,
                    InlineExitCollector* exit_collector,
                    intptr_t osr_id);
 
   FlowGraph* BuildGraph();
 
   const ParsedFunction& parsed_function() const { return parsed_function_; }
   const Function& function() const { return parsed_function_.function(); }
   const ZoneGrowableArray<const ICData*>& ic_data_array() const {
     return ic_data_array_;
   }
 
   void Bailout(const char* reason) const;
 
   intptr_t AllocateBlockId() { return ++last_used_block_id_; }
   void SetInitialBlockId(intptr_t id) { last_used_block_id_ = id; }
 
-  intptr_t GetNextDeoptId() {
-    // TODO(rmacnak): Record current scope / context level.
-    return thread()->GetNextDeoptId();
-  }
+  intptr_t GetNextDeoptId() const;
 
   intptr_t context_level() const;
 
   void IncrementLoopDepth() { ++loop_depth_; }
   void DecrementLoopDepth() { --loop_depth_; }
   intptr_t loop_depth() const { return loop_depth_; }
 
   // Manage the currently active try index.
   void set_try_index(intptr_t value) { try_index_ = value; }
   intptr_t try_index() const { return try_index_; }
@@ skipping 60 matching lines @@
 
   intptr_t parameter_count() const {
     return num_copied_params_ + num_non_copied_params_;
   }
   intptr_t variable_count() const {
     return parameter_count() + num_stack_locals_;
   }
 
   const ParsedFunction& parsed_function_;
   const ZoneGrowableArray<const ICData*>& ic_data_array_;
+  ZoneGrowableArray<intptr_t>* context_level_array_;

[Vyacheslav Egorov (Google), 2017/05/31 14:29:51]

it might be worth adding a comment here that this array contains 

(deopt_id, context_level)

tuples.

[rmacnak, 2017/05/31 18:03:17]

Added.

 
   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 try_index_;
   intptr_t catch_try_index_;
   intptr_t loop_depth_;
@@ skipping 360 matching lines @@
   // Output parameters.
   GrowableArray<TargetEntryInstr**> true_successor_addresses_;
   GrowableArray<TargetEntryInstr**> false_successor_addresses_;
 
   TokenPosition condition_token_pos_;
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_FLOW_GRAPH_BUILDER_H_