d8 drops into a shell if no files are passed on command line

src/d8.cc

-// Copyright 2009 the V8 project authors. All rights reserved.
+// Copyright 2011 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
 //       with the distribution.
@@ skipping 902 matching lines @@
   return 0;
 }
 
 
 int Shell::Main(int argc, char* argv[]) {
   // Figure out if we're requested to stress the optimization
   // infrastructure by running tests multiple times and forcing
   // optimization in the last run.
   bool FLAG_stress_opt = false;
   bool FLAG_stress_deopt = false;
-  bool run_shell = (argc == 1);
+  bool FLAG_run_shell = false;
 
   for (int i = 0; i < argc; i++) {
     if (strcmp(argv[i], "--stress-opt") == 0) {
       FLAG_stress_opt = true;
       argv[i] = NULL;
     } else if (strcmp(argv[i], "--stress-deopt") == 0) {
       FLAG_stress_deopt = true;
       argv[i] = NULL;
     } else if (strcmp(argv[i], "--noalways-opt") == 0) {
       // No support for stressing if we can't use --always-opt.
       FLAG_stress_opt = false;
       FLAG_stress_deopt = false;
     } else if (strcmp(argv[i], "--shell") == 0) {
-      run_shell = true;
+      FLAG_run_shell = true;
       argv[i] = NULL;
     }
   }
 
   v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
 
+  // Allow SetFlagsFromCommandLine to decrement argc before deciding to
+  // run the shell or not.
+  bool run_shell = FLAG_run_shell || (argc == 1);
+
   Initialize();
 
   int result = 0;
   if (FLAG_stress_opt || FLAG_stress_deopt) {
     v8::Testing::SetStressRunType(
         FLAG_stress_opt ? v8::Testing::kStressTypeOpt
             : v8::Testing::kStressTypeDeopt);
     int stress_runs = v8::Testing::GetStressRuns();
     for (int i = 0; i < stress_runs && result == 0; i++) {
       printf("============ Stress %d/%d ============\n", i + 1, stress_runs);
@@ skipping 24 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif