src/os/windows/vm/os_windows.cpp

*** 1418,1427 ****
--- 1418,1430 ----
     return 0;
  }
  
  bool os::dll_address_to_library_name(address addr, char* buf,
                                       int buflen, int* offset) {
+   // buf is not optional, but offset is optional
+   assert(buf != NULL, "sanity check");
+ 
  // NOTE: the reason we don't use SymGetModuleInfo() is it doesn't always
  //       return the full path to the DLL file, sometimes it returns path
  //       to the corresponding PDB file (debug info); sometimes it only
  //       returns partial path, which makes life painful.
  
*** 1433,1455 ****
     if (enumerate_modules(pid, _locate_module_by_addr, (void *)&mi)) {
        // buf already contains path name
        if (offset) *offset = addr - mi.base_addr;
        return true;
     } else {
!       if (buf) buf[0] = '\0';
        if (offset) *offset = -1;
        return false;
     }
  }
  
  bool os::dll_address_to_function_name(address addr, char *buf,
                                        int buflen, int *offset) {
    if (Decoder::decode(addr, buf, buflen, offset)) {
      return true;
    }
    if (offset != NULL)  *offset  = -1;
!   if (buf != NULL) buf[0] = '\0';
    return false;
  }
  
  // save the start and end address of jvm.dll into param[0] and param[1]
  static int _locate_jvm_dll(int pid, char* mod_fname, address base_addr,
--- 1436,1461 ----
     if (enumerate_modules(pid, _locate_module_by_addr, (void *)&mi)) {
        // buf already contains path name
        if (offset) *offset = addr - mi.base_addr;
        return true;
     } else {
!       buf[0] = '\0';
        if (offset) *offset = -1;
        return false;
     }
  }
  
  bool os::dll_address_to_function_name(address addr, char *buf,
                                        int buflen, int *offset) {
+   // buf is not optional, but offset is optional
+   assert(buf != NULL, "sanity check");
+ 
    if (Decoder::decode(addr, buf, buflen, offset)) {
      return true;
    }
    if (offset != NULL)  *offset  = -1;
!   buf[0] = '\0';
    return false;
  }
  
  // save the start and end address of jvm.dll into param[0] and param[1]
  static int _locate_jvm_dll(int pid, char* mod_fname, address base_addr,