Provide better error messages when we fail to build the builtin lib.

runtime/bin/builtin_in.cc

 // Copyright (c) 2011, 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 <stdlib.h>
 #include <string.h>
 
 #include "include/dart_api.h"
 
 #include "bin/builtin.h"
@@ skipping 56 matching lines @@
   int argument_count_;
 } BuiltinEntries[] = {
   BUILTIN_NATIVE_LIST(REGISTER_FUNCTION)
 };
 
 
 static Dart_NativeFunction native_lookup(Dart_Handle name,
                                          int argument_count) {
   const char* function_name = NULL;
   Dart_Handle result = Dart_StringToCString(name, &function_name);
-  ASSERT(!Dart_IsError(result));
+  DART_CHECK_VALID(result);
   ASSERT(function_name != NULL);
   int num_entries = sizeof(BuiltinEntries) / sizeof(struct NativeEntries);
   for (int i = 0; i < num_entries; i++) {
     struct NativeEntries* entry = &(BuiltinEntries[i]);
     if (!strcmp(function_name, entry->name_)) {
       if (entry->argument_count_ == argument_count) {
         return reinterpret_cast<Dart_NativeFunction>(entry->function_);
       } else {
         // Wrong number of arguments.
         // TODO(regis): Should we pass a buffer for error reporting?
         return NULL;
       }
     }
   }
   return NULL;
 }
 
 
 void Builtin_LoadLibrary() {
   Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
   Dart_Handle result = Dart_LookupLibrary(url);
   if (!Dart_IsError(result)) {
     // Builtin library already loaded.
     return;
   }
 
   // Load the library.
   Dart_Handle source = Dart_NewString(Builtin_source_);
   Dart_Handle builtin_lib = Dart_LoadLibrary(url, source);
-  ASSERT(!Dart_IsError(builtin_lib));
+  DART_CHECK_VALID(builtin_lib);
 
   // Lookup the core libraries and inject the builtin library into them.
   Dart_Handle core_lib = Dart_LookupLibrary(Dart_NewString("dart:core"));
-  ASSERT(!Dart_IsError(core_lib));
+  DART_CHECK_VALID(core_lib);
   result = Dart_LibraryImportLibrary(core_lib, builtin_lib);
-  ASSERT(!Dart_IsError(result));
+  DART_CHECK_VALID(result);
 
   Dart_Handle coreimpl_lib =
       Dart_LookupLibrary(Dart_NewString("dart:coreimpl"));
-  ASSERT(!Dart_IsError(coreimpl_lib));
+  DART_CHECK_VALID(coreimpl_lib);
   result = Dart_LibraryImportLibrary(coreimpl_lib, builtin_lib);
-  ASSERT(!Dart_IsError(result));
+  DART_CHECK_VALID(result);
   result = Dart_LibraryImportLibrary(builtin_lib, coreimpl_lib);
-  ASSERT(!Dart_IsError(result));
+  DART_CHECK_VALID(result);
 
   // Create a native wrapper "EventHandlerNativeWrapper" so that we can add a
   // native field to store the event handle for implementing all
   // event operations.
   Dart_Handle name = Dart_NewString("EventHandlerNativeWrapper");
   const int kNumEventHandlerFields = 1;
   result = Dart_CreateNativeWrapperClass(builtin_lib,
                                          name,
                                          kNumEventHandlerFields);
-  ASSERT(!Dart_IsError(result));
+  DART_CHECK_VALID(result);
 }
 
 
 void Builtin_ImportLibrary(Dart_Handle library) {
   Builtin_LoadLibrary();
 
   Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
   Dart_Handle builtin_lib = Dart_LookupLibrary(url);
-  ASSERT(!Dart_IsError(builtin_lib));
+  DART_CHECK_VALID(builtin_lib);
   Dart_Handle result = Dart_LibraryImportLibrary(library, builtin_lib);
-  ASSERT(!Dart_IsError(result));
+  DART_CHECK_VALID(result);
 }
 
 
 void Builtin_SetNativeResolver() {
   Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
   Dart_Handle builtin_lib = Dart_LookupLibrary(url);
-  ASSERT(!Dart_IsError(builtin_lib));
+  DART_CHECK_VALID(builtin_lib);
   Dart_Handle result = Dart_SetNativeResolver(builtin_lib, native_lookup);
-  ASSERT(!Dart_IsError(result));
+  DART_CHECK_VALID(result);
 }