Enable --trace when --multipass is on. Bugfix in bailout condition....

src/cfg.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 50 matching lines @@
     BAILOUT("empty function body");
   }
 
   Cfg::Reset(fun);
   StatementBuilder builder;
   builder.VisitStatements(body);
   Cfg* cfg = builder.cfg();
   if (cfg == NULL) {
     BAILOUT("unsupported statement type");
   }
-
-  ASSERT(!cfg->has_exit());  // Return on all paths.
+  if (cfg->has_exit()) {
+    BAILOUT("control path without explicit return");
+  }
   cfg->PrependEntryNode(fun);
   return cfg;
 }
 
 #undef BAILOUT
 
 
 void Cfg::PrependEntryNode(FunctionLiteral* fun) {
   ASSERT(!is_empty());
   entry_ = new EntryNode(fun, InstructionBlock::cast(entry()));
@@ skipping 370 matching lines @@
 void ExitNode::Print() {
   if (!is_marked_) {
     is_marked_ = true;
     PrintF("L%d:\nExit\n\n", number());
   }
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal