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

runtime/vm/raw_object_snapshot.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.
 
 #include "vm/bigint_operations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
@@ skipping 940 matching lines @@
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   *reader->StringHandle() ^= reader->ReadObjectImpl();
   script.set_url(*reader->StringHandle());
   *reader->StringHandle() ^= String::null();
   script.set_source(*reader->StringHandle());
   TokenStream& stream = TokenStream::Handle();
   stream ^= reader->ReadObjectImpl();
   script.set_tokens(stream);
+  TypedData& array = TypedData::Handle();
+  array ^= reader->ReadObjectImpl();
+  script.set_token_pos_to_line_nr(array);
 
   script.raw_ptr()->line_offset_ = reader->Read<int32_t>();
   script.raw_ptr()->col_offset_ = reader->Read<int32_t>();
   script.raw_ptr()->kind_ = reader->Read<int8_t>();
 
   return script.raw();
 }
 
 
 void RawScript::WriteTo(SnapshotWriter* writer,
                         intptr_t object_id,
                         Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT(tokens_ != TokenStream::null());
   ASSERT(((kind == Snapshot::kScript) &&
           !RawObject::IsCreatedFromSnapshot(writer->GetObjectTags(this))) ||
          (kind == Snapshot::kFull));
 
   // Write out the serialization header value for this object.
   writer->WriteInlinedObjectHeader(object_id);
 
   // Write out the class and tags information.
   writer->WriteVMIsolateObject(kScriptCid);
   writer->WriteIntptrValue(writer->GetObjectTags(this));
 
   // Write out all the object pointer fields.
   writer->WriteObjectImpl(ptr()->url_);
   writer->WriteObjectImpl(ptr()->tokens_);
+  writer->WriteObjectImpl(ptr()->token_pos_to_line_nr_);
 
   writer->Write<int32_t>(ptr()->line_offset_);
   writer->Write<int32_t>(ptr()->col_offset_);
   writer->Write<int8_t>(ptr()->kind_);
 }
 
 
 RawLibrary* Library::ReadFrom(SnapshotReader* reader,
                               intptr_t object_id,
                               intptr_t tags,
@@ skipping 1784 matching lines @@
     // We do not allow objects with native fields in an isolate message.
     writer->SetWriteException(Exceptions::kArgument,
                               "Illegal argument in isolate message"
                               " : (object is a UserTag)");
   } else {
     UNREACHABLE();
   }
 }
 
 }  // namespace dart