github.com/c12o16h1/go/src@v0.0.0-20200114212001-5a151c0f00ed/runtime/cgo/gcc_libinit_windows.c (about)

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build cgo
     6  #define WIN64_LEAN_AND_MEAN
     7  #include <windows.h>
     8  #include <process.h>
     9  
    10  #include <stdio.h>
    11  #include <stdlib.h>
    12  #include <errno.h>
    13  
    14  #include "libcgo.h"
    15  
    16  static volatile LONG runtime_init_once_gate = 0;
    17  static volatile LONG runtime_init_once_done = 0;
    18  
    19  static CRITICAL_SECTION runtime_init_cs;
    20  
    21  static HANDLE runtime_init_wait;
    22  static int runtime_init_done;
    23  
    24  // Pre-initialize the runtime synchronization objects
    25  void
    26  _cgo_preinit_init() {
    27  	 runtime_init_wait = CreateEvent(NULL, TRUE, FALSE, NULL);
    28  	 if (runtime_init_wait == NULL) {
    29  		fprintf(stderr, "runtime: failed to create runtime initialization wait event.\n");
    30  		abort();
    31  	 }
    32  
    33  	 InitializeCriticalSection(&runtime_init_cs);
    34  }
    35  
    36  // Make sure that the preinit sequence has run.
    37  void
    38  _cgo_maybe_run_preinit() {
    39  	 if (!InterlockedExchangeAdd(&runtime_init_once_done, 0)) {
    40  			if (InterlockedIncrement(&runtime_init_once_gate) == 1) {
    41  				 _cgo_preinit_init();
    42  				 InterlockedIncrement(&runtime_init_once_done);
    43  			} else {
    44  				 // Decrement to avoid overflow.
    45  				 InterlockedDecrement(&runtime_init_once_gate);
    46  				 while(!InterlockedExchangeAdd(&runtime_init_once_done, 0)) {
    47  						Sleep(0);
    48  				 }
    49  			}
    50  	 }
    51  }
    52  
    53  void
    54  x_cgo_sys_thread_create(void (*func)(void*), void* arg) {
    55  	uintptr_t thandle;
    56  
    57  	thandle = _beginthread(func, 0, arg);
    58  	if(thandle == -1) {
    59  		fprintf(stderr, "runtime: failed to create new OS thread (%d)\n", errno);
    60  		abort();
    61  	}
    62  }
    63  
    64  int
    65  _cgo_is_runtime_initialized() {
    66  	 EnterCriticalSection(&runtime_init_cs);
    67  	 int status = runtime_init_done;
    68  	 LeaveCriticalSection(&runtime_init_cs);
    69  	 return status;
    70  }
    71  
    72  uintptr_t
    73  _cgo_wait_runtime_init_done(void) {
    74  	void (*pfn)(struct context_arg*);
    75  
    76  	 _cgo_maybe_run_preinit();
    77  	while (!_cgo_is_runtime_initialized()) {
    78  			WaitForSingleObject(runtime_init_wait, INFINITE);
    79  	}
    80  	pfn = _cgo_get_context_function();
    81  	if (pfn != nil) {
    82  		struct context_arg arg;
    83  
    84  		arg.Context = 0;
    85  		(*pfn)(&arg);
    86  		return arg.Context;
    87  	}
    88  	return 0;
    89  }
    90  
    91  void
    92  x_cgo_notify_runtime_init_done(void* dummy) {
    93  	 _cgo_maybe_run_preinit();
    94  
    95  	 EnterCriticalSection(&runtime_init_cs);
    96  	runtime_init_done = 1;
    97  	 LeaveCriticalSection(&runtime_init_cs);
    98  
    99  	 if (!SetEvent(runtime_init_wait)) {
   100  		fprintf(stderr, "runtime: failed to signal runtime initialization complete.\n");
   101  		abort();
   102  	}
   103  }
   104  
   105  // The context function, used when tracing back C calls into Go.
   106  static void (*cgo_context_function)(struct context_arg*);
   107  
   108  // Sets the context function to call to record the traceback context
   109  // when calling a Go function from C code. Called from runtime.SetCgoTraceback.
   110  void x_cgo_set_context_function(void (*context)(struct context_arg*)) {
   111  	EnterCriticalSection(&runtime_init_cs);
   112  	cgo_context_function = context;
   113  	LeaveCriticalSection(&runtime_init_cs);
   114  }
   115  
   116  // Gets the context function.
   117  void (*(_cgo_get_context_function(void)))(struct context_arg*) {
   118  	void (*ret)(struct context_arg*);
   119  
   120  	EnterCriticalSection(&runtime_init_cs);
   121  	ret = cgo_context_function;
   122  	LeaveCriticalSection(&runtime_init_cs);
   123  	return ret;
   124  }