Fail sooner and with better error message when attempting precompilation on IA32.

runtime/vm/flow_graph_compiler.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/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
@@ skipping 99 matching lines @@
                     "Run fast unoptimized code only.");
 
 
 DECLARE_FLAG(bool, lazy_dispatchers);
 DECLARE_FLAG(bool, interpret_irregexp);
 DECLARE_FLAG(bool, enable_mirrors);
 DECLARE_FLAG(bool, link_natives_lazily);
 
 static void PrecompileModeHandler(bool value) {
   if (value) {
+#if defined(TARGET_ARCH_IA32)
+    FATAL("Precompilation not supported on IA32");
+#endif
+
     NooptModeHandler(true);
     FLAG_lazy_dispatchers = false;
     FLAG_interpret_irregexp = true;
     FLAG_enable_mirrors = false;
     FLAG_precompile_collect_closures = true;
     FLAG_link_natives_lazily = true;
     FLAG_fields_may_be_reset = true;
     FLAG_allow_absolute_addresses = false;
   }
 }
@@ skipping 1703 matching lines @@
 
 
 void FlowGraphCompiler::FrameStateClear() {
   ASSERT(!is_optimizing());
   frame_state_.TruncateTo(0);
 }
 #endif
 
 
 }  // namespace dart