lldb/test/API/linux/thread/create_during_instruction_step/main.cpp

   1 // This file deliberately uses low level linux-specific API for thread creation because:
   2 // - instruction-stepping over thread creation using higher-level functions was very slow
   3 // - it was also unreliable due to single-stepping bugs unrelated to this test
   4 // - some threading libraries do not create or destroy threads when we would expect them to
   5
   6 #include <sched.h>
   7
   8 #include <atomic>
   9 #include <cstdio>
  10
  11 enum { STACK_SIZE = 0x2000 };
  12
  13 static uint8_t child_stack[STACK_SIZE];
  14
  15 pid_t child_tid;
  16
  17 std::atomic<bool> flag(false);
  18
  19 int thread_main(void *)
  20 {
  21     while (! flag) // Make sure the thread does not exit prematurely
  22         ;
  23
  24     return 0;
  25 }
  26
  27 int main ()
  28 {
  29     int ret = clone(thread_main,
  30             child_stack + STACK_SIZE/2, // Don't care whether the stack grows up or down,
  31                                         // just point to the middle
  32             CLONE_CHILD_CLEARTID | CLONE_FILES | CLONE_FS | CLONE_PARENT_SETTID |
  33             CLONE_SIGHAND | CLONE_SYSVSEM | CLONE_THREAD | CLONE_VM,
  34             nullptr, // thread_main argument
  35             &child_tid);
  36
  37     if (ret == -1)
  38     {
  39         perror("clone");
  40         return 1;
  41     }
  42
  43     flag = true;
  44
  45     return 0;
  46 }