We can't print the AST or the source for stubs.

src/codegen.cc

 // Copyright 2012 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 68 matching lines @@
     if (info->IsStub()) {
       const char* name =
           CodeStub::MajorName(info->code_stub()->MajorKey(), true);
       PrintF("%s", name == NULL ? "<unknown>" : name);
     } else {
       info->function()->name()->ShortPrint();
     }
     PrintF(" ***\n");
   }
 
-  if (print_source) {
+  if (!info->IsStub() && print_source) {
     PrintF("--- Source from AST ---\n%s\n",
            PrettyPrinter().PrintProgram(info->function()));
   }
 
-  if (print_ast) {
+  if (!info->IsStub() && print_ast) {
     PrintF("--- AST ---\n%s\n",
            AstPrinter().PrintProgram(info->function()));
   }
 #endif  // DEBUG
 }
 
 
 Handle<Code> CodeGenerator::MakeCodeEpilogue(MacroAssembler* masm,
                                              Code::Flags flags,
                                              CompilationInfo* info) {
@@ skipping 113 matching lines @@
   ASSERT(result_size_ == 1 || result_size_ == 2);
 #ifdef _WIN64
   return result | ((result_size_ == 1) ? 0 : 2);
 #else
   return result;
 #endif
 }
 
 
 } }  // namespace v8::internal