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

runtime/vm/intrinsifier.cc

 // 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.
 // Class for intrinsifying functions.
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/cpu.h"
 #include "vm/flags.h"
 #include "vm/flow_graph.h"
@@ skipping 147 matching lines @@
 }
 #endif
 
 
 bool Intrinsifier::GraphIntrinsify(const ParsedFunction& parsed_function,
                                    FlowGraphCompiler* compiler) {
 #if !defined(TARGET_ARCH_DBC)
   ZoneGrowableArray<const ICData*>* ic_data_array =
       new ZoneGrowableArray<const ICData*>();
   FlowGraphBuilder builder(parsed_function, *ic_data_array,
-                           NULL,  // NULL = not inlining.
-                           Compiler::kNoOSRDeoptId);
+                           /* not building var desc */ NULL,
+                           /* not inlining */ NULL, Compiler::kNoOSRDeoptId);
 
   intptr_t block_id = builder.AllocateBlockId();
   TargetEntryInstr* normal_entry =
       new TargetEntryInstr(block_id, CatchClauseNode::kInvalidTryIndex,
                            Thread::Current()->GetNextDeoptId());
   GraphEntryInstr* graph_entry = new GraphEntryInstr(
       parsed_function, normal_entry, Compiler::kNoOSRDeoptId);
   FlowGraph* graph = new FlowGraph(parsed_function, graph_entry, block_id);
   const Function& function = parsed_function.function();
   switch (function.recognized_kind()) {
@@ skipping 993 matching lines @@
 }
 
 
 void Intrinsifier::RegExp_ExecuteMatchSticky(Assembler* assembler) {
   IntrinsifyRegExpExecuteMatch(assembler, /*sticky=*/true);
 }
 #endif  // !defined(TARGET_ARCH_DBC)
 
 
 }  // namespace dart