Fix precompiler

runtime/vm/precompiler.cc

 // Copyright (c) 2015, 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.
 
 #include "vm/precompiler.h"
 
 #include "vm/aot_optimizer.h"
 #include "vm/assembler.h"
 #include "vm/ast_printer.h"
 #include "vm/branch_optimizer.h"
@@ skipping 1995 matching lines @@
       // Collect all instance fields that are loaded in the graph and
       // have non-generic type feedback attached to them that can
       // potentially affect optimizations.
       if (optimized()) {
 #ifndef PRODUCT
         TimelineDurationScope tds(thread(),
                                   compiler_timeline,
                                   "OptimizationPasses");
 #endif  // !PRODUCT
         inline_id_to_function.Add(&function);
-        inline_id_to_token_pos.Add(function.token_pos());
+        // We do not add the token position now because we don't know the
+        // position of the inlined call until later. A side effect of this
+        // is that the length of |inline_id_to_function| is always larger
+        // than the length of |inline_id_to_token_pos| by one.
+        // Top scope function has no caller (-1). We do this because we expect
+        // all token positions to be at an inlined call.
         // Top scope function has no caller (-1).
         caller_inline_id.Add(-1);
         CSTAT_TIMER_SCOPE(thread(), graphoptimizer_timer);
 
         AotOptimizer optimizer(flow_graph,
                                use_speculative_inlining,
                                &inlining_black_list);
         optimizer.PopulateWithICData();
 
         optimizer.ApplyClassIds();
@@ skipping 508 matching lines @@
       CompilationPipeline::New(thread->zone(), function);
 
   ASSERT(FLAG_precompiled_mode);
   const bool optimized = function.IsOptimizable();  // False for natives.
   return PrecompileFunctionHelper(pipeline, function, optimized);
 }
 
 #endif  // DART_PRECOMPILER
 
 }  // namespace dart