libgo/runtime/go-cgo.c

   1 /* go-cgo.c -- SWIG support routines for libgo.
   2
   3    Copyright 2011 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include "runtime.h"
   8
   9 /* Used for _cgo_wait_runtime_init_done.  This is based on code in
  10    runtime/cgo/gcc_libinit.c in the master library.  */
  11
  12 static pthread_cond_t runtime_init_cond = PTHREAD_COND_INITIALIZER;
  13 static pthread_mutex_t runtime_init_mu = PTHREAD_MUTEX_INITIALIZER;
  14 static _Bool runtime_init_done;
  15
  16 /* This is called by exported cgo functions to ensure that the runtime
  17    has been initialized before we enter the function.  This is needed
  18    when building with -buildmode=c-archive or similar.  */
  19
  20 void
  21 _cgo_wait_runtime_init_done (void)
  22 {
  23   int err;
  24
  25   if (__atomic_load_n (&runtime_init_done, __ATOMIC_ACQUIRE))
  26     return;
  27
  28   err = pthread_mutex_lock (&runtime_init_mu);
  29   if (err != 0)
  30     abort ();
  31   while (!__atomic_load_n (&runtime_init_done, __ATOMIC_ACQUIRE))
  32     {
  33       err = pthread_cond_wait (&runtime_init_cond, &runtime_init_mu);
  34       if (err != 0)
  35         abort ();
  36     }
  37   err = pthread_mutex_unlock (&runtime_init_mu);
  38   if (err != 0)
  39     abort ();
  40 }
  41
  42 /* This is called by runtime_main after the Go runtime is
  43    initialized.  */
  44
  45 void
  46 _cgo_notify_runtime_init_done (void)
  47 {
  48   int err;
  49
  50   err = pthread_mutex_lock (&runtime_init_mu);
  51   if (err != 0)
  52     abort ();
  53   __atomic_store_n (&runtime_init_done, 1, __ATOMIC_RELEASE);
  54   err = pthread_cond_broadcast (&runtime_init_cond);
  55   if (err != 0)
  56     abort ();
  57   err = pthread_mutex_unlock (&runtime_init_mu);
  58   if (err != 0)
  59     abort ();
  60 }
  61
  62 // runtime_iscgo is set to true if some cgo code is linked in.
  63 // This is done by a constructor in the cgo generated code.
  64 _Bool runtime_iscgo;