Only reload libraries when they may have been modified.

runtime/bin/gen_snapshot.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.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 473 matching lines @@
   if (Dart_IsError(resolved_uri)) {
     return resolved_uri;
   }
   // Now load the contents of the specified uri.
   const char* resolved_uri_string = DartUtils::GetStringValue(resolved_uri);
   Dart_Handle source =  LoadUrlContents(resolved_uri_string);
   if (Dart_IsError(source)) {
     return source;
   }
   if (IsSnapshottingForPrecompilation()) {
-    return Dart_LoadScript(resolved_uri, source, 0, 0);
+    return Dart_LoadScript(resolved_uri, Dart_Null(), source, 0, 0);
   } else {
-    return Dart_LoadLibrary(resolved_uri, source, 0, 0);
+    return Dart_LoadLibrary(resolved_uri, Dart_Null(), source, 0, 0);
   }
 }
 
 
 static Builtin::BuiltinLibraryId BuiltinId(const char* url) {
   if (DartUtils::IsDartBuiltinLibURL(url)) {
     return Builtin::kBuiltinLibrary;
   }
   if (DartUtils::IsDartIOLibURL(url)) {
     return Builtin::kIOLibrary;
@@ skipping 44 matching lines @@
     if (tag == Dart_kImportTag) {
       return Builtin::LoadLibrary(url, builtinId);
     }
     ASSERT(tag == Dart_kSourceTag);
     return DartUtils::NewError("Unable to part '%s' ", url_string);
   }
 
   if (libraryBuiltinId != Builtin::kInvalidLibrary) {
     // Special case for parting sources of a builtin library.
     if (tag == Dart_kSourceTag) {
-      return Dart_LoadSource(library, url,
+      return Dart_LoadSource(library, url, Dart_Null(),
           Builtin::PartSource(libraryBuiltinId, url_string), 0, 0);
     }
     ASSERT(tag == Dart_kImportTag);
     return DartUtils::NewError("Unable to import '%s' ", url_string);
   }
 
   Dart_Handle resolved_url = url;
   if (mapped_url_string != NULL) {
     // Mapped urls are relative to working directory.
     resolved_url = ResolveUriInWorkingDirectory(mapped_url_string);
     if (Dart_IsError(resolved_url)) {
       return resolved_url;
     }
   }
   const char* resolved_uri_string = DartUtils::GetStringValue(resolved_url);
   Dart_Handle source =  LoadUrlContents(resolved_uri_string);
   if (Dart_IsError(source)) {
     return source;
   }
   if (tag == Dart_kImportTag) {
-    return Dart_LoadLibrary(url, source, 0, 0);
+    return Dart_LoadLibrary(url, Dart_Null(), source, 0, 0);
   } else {
     ASSERT(tag == Dart_kSourceTag);
-    return Dart_LoadSource(library, url, source, 0, 0);
+    return Dart_LoadSource(library, url, Dart_Null(), source, 0, 0);
   }
 }
 
 
 static Dart_Handle LoadGenericSnapshotCreationScript(
     Builtin::BuiltinLibraryId id) {
   Dart_Handle source = Builtin::Source(id);
   if (Dart_IsError(source)) {
     return source;  // source contains the error string.
   }
@@ skipping 118 matching lines @@
              "import '%s';",
              DartUtils::GetStringValue(library_string));
     Dart_Handle script_handle = Dart_NewStringFromCString(load_buffer);
     memset(load_buffer, 0, kLoadBufferMaxSize);
     snprintf(load_buffer,
              kLoadBufferMaxSize,
              "dart:_snapshot_%zu",
              lib_index);
     Dart_Handle script_url = Dart_NewStringFromCString(load_buffer);
     free(load_buffer);
-    Dart_Handle loaded = Dart_LoadLibrary(script_url, script_handle, 0, 0);
+    Dart_Handle loaded = Dart_LoadLibrary(script_url, Dart_Null(),
+                                          script_handle, 0, 0);
     DART_CHECK_VALID(loaded);
 
     // Do a fresh lookup
     library = Dart_LookupLibrary(library_string);
   }
 
   DART_CHECK_VALID(library);
   Dart_Handle result =  Dart_SetNativeResolver(library,
                                                &StubNativeLookup,
                                                &StubNativeSymbol);
@@ skipping 619 matching lines @@
   EventHandler::Stop();
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }