Add a runtime flag to control availability of dart:mirrors.

runtime/vm/bootstrap.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/bootstrap.h"
 
 #include "include/dart_api.h"
 
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
+DECLARE_FLAG(bool, use_mirrors);
+
 #define INIT_LIBRARY(index, name, source, patch)                               \
   { index,                                                                     \
     "dart:"#name, source,                                                      \
     "dart:"#name"-patch", patch }                                              \
 
 typedef struct {
   ObjectStore::BootstrapLibraryId index_;
   const char* uri_;
   const char** source_paths_;
   const char* patch_uri_;
@@ skipping 237 matching lines @@
   // library tag handler so that we can load all the bootstrap libraries.
   isolate->set_library_tag_handler(BootstrapLibraryTagHandler);
 
   HANDLESCOPE(isolate);
 
   // Create library objects for all the bootstrap libraries.
   for (intptr_t i = 0;
        bootstrap_libraries[i].index_ != ObjectStore::kNone;
        ++i) {
     uri = Symbols::New(bootstrap_libraries[i].uri_);
+
+    if (!FLAG_use_mirrors && (uri.raw() == Symbols::DartMirrors().raw())) {
+      continue;
+    }
+
     lib = Library::LookupLibrary(uri);
     if (lib.IsNull()) {
       lib = Library::NewLibraryHelper(uri, false);
       lib.SetLoadRequested();
       lib.Register();
     }
     isolate->object_store()->set_bootstrap_library(
         bootstrap_libraries[i].index_, lib);
   }
 
   // Load, compile and patch bootstrap libraries.
   for (intptr_t i = 0;
        bootstrap_libraries[i].index_ != ObjectStore::kNone;
        ++i) {
     uri = Symbols::New(bootstrap_libraries[i].uri_);
+
+    if (!FLAG_use_mirrors && (uri.raw() == Symbols::DartMirrors().raw())) {
+      continue;
+    }
+
     lib = Library::LookupLibrary(uri);
     ASSERT(!lib.IsNull());
     source = GetLibrarySource(lib, uri, false);
     if (source.IsNull()) {
       const String& message = String::Handle(
           String::NewFormatted("Unable to find dart source for %s",
                                uri.ToCString()));
       error ^= ApiError::New(message);
       break;
     }
@@ skipping 28 matching lines @@
     Compiler::CompileClass(cls);
   }
 
   // Restore the library tag handler for the isolate.
   isolate->set_library_tag_handler(saved_tag_handler);
 
   return error.raw();
 }
 
 }  // namespace dart