Significantly improve performance of code coverage tool by precomputing a map token_pos->line numbe…

runtime/vm/coverage.cc

 // 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.
 
 #include "vm/coverage.h"
 
 #include "include/dart_api.h"
 
 #include "vm/compiler.h"
 #include "vm/isolate.h"
@@ skipping 70 matching lines @@
   Script& script = Script::Handle();
   String& saved_url = String::Handle();
   String& url = String::Handle();
 
   int i = 0;
   while (i < functions.Length()) {
     HANDLESCOPE(isolate);
     function ^= functions.At(i);
     JSONObject jsobj(&jsarr);
     script = function.script();
+    // Makes token_pos to line-number lookup faster.
+    script.ComputeTokenPosToLineNumberArray();

[Ivan Posva, 2014/06/10 00:14:58]

As discussed we might want to cache this array only locally and pass it as a
parameter to CompileAndAdd.

     saved_url = script.url();
     jsobj.AddProperty("source", saved_url.ToCString());
     jsobj.AddProperty("script", script);
     JSONArray hits_arr(&jsobj, "hits");
 
     // We stay within this loop while we are seeing functions from the same
     // source URI.
     while (i < functions.Length()) {
       function ^= functions.At(i);
       script = function.script();
@@ skipping 95 matching lines @@
           // functions.
           PrintClass(cls, jsarr);
         }
       }
     }
   }
 }
 
 
 }  // namespace dart