gcc/libgo/runtime/thread.c

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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include <errno.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "runtime.h"
#include "go-assert.h"
/* For targets which don't have the required sync support. Really
these should be provided by gcc itself. FIXME. */
#if !defined (HAVE_SYNC_BOOL_COMPARE_AND_SWAP_4) || !defined (HAVE_SYNC_BOOL_COMPARE_AND_SWAP_8) || !defined (HAVE_SYNC_FETCH_AND_ADD_4) || !defined (HAVE_SYNC_ADD_AND_FETCH_8)
static pthread_mutex_t sync_lock = PTHREAD_MUTEX_INITIALIZER;
#endif
#ifndef HAVE_SYNC_BOOL_COMPARE_AND_SWAP_4
_Bool
__sync_bool_compare_and_swap_4 (uint32*, uint32, uint32)
__attribute__ ((visibility ("hidden")));
_Bool
__sync_bool_compare_and_swap_4 (uint32* ptr, uint32 old, uint32 new)
{
int i;
_Bool ret;
i = pthread_mutex_lock (&sync_lock);
__go_assert (i == 0);
if (*ptr != old)
ret = 0;
else
{
*ptr = new;
ret = 1;
}
i = pthread_mutex_unlock (&sync_lock);
__go_assert (i == 0);
return ret;
}
#endif
#ifndef HAVE_SYNC_BOOL_COMPARE_AND_SWAP_8
_Bool
__sync_bool_compare_and_swap_8 (uint64*, uint64, uint64)
__attribute__ ((visibility ("hidden")));
_Bool
__sync_bool_compare_and_swap_8 (uint64* ptr, uint64 old, uint64 new)
{
int i;
_Bool ret;
i = pthread_mutex_lock (&sync_lock);
__go_assert (i == 0);
if (*ptr != old)
ret = 0;
else
{
*ptr = new;
ret = 1;
}
i = pthread_mutex_unlock (&sync_lock);
__go_assert (i == 0);
return ret;
}
#endif
#ifndef HAVE_SYNC_FETCH_AND_ADD_4
uint32
__sync_fetch_and_add_4 (uint32*, uint32)
__attribute__ ((visibility ("hidden")));
uint32
__sync_fetch_and_add_4 (uint32* ptr, uint32 add)
{
int i;
uint32 ret;
i = pthread_mutex_lock (&sync_lock);
__go_assert (i == 0);
ret = *ptr;
*ptr += add;
i = pthread_mutex_unlock (&sync_lock);
__go_assert (i == 0);
return ret;
}
#endif
#ifndef HAVE_SYNC_ADD_AND_FETCH_8
uint64
__sync_add_and_fetch_8 (uint64*, uint64)
__attribute__ ((visibility ("hidden")));
uint64
__sync_add_and_fetch_8 (uint64* ptr, uint64 add)
{
int i;
uint64 ret;
i = pthread_mutex_lock (&sync_lock);
__go_assert (i == 0);
*ptr += add;
ret = *ptr;
i = pthread_mutex_unlock (&sync_lock);
__go_assert (i == 0);
return ret;
}
#endif
// Called to initialize a new m (including the bootstrap m).
void
runtime_minit(void)
{
byte* stack;
size_t stacksize;
stack_t ss;
sigset_t sigs;
// Initialize signal handling.
runtime_m()->gsignal = runtime_malg(32*1024, &stack, &stacksize); // OS X wants >=8K, Linux >=2K
ss.ss_sp = stack;
ss.ss_flags = 0;
ss.ss_size = stacksize;
if(sigaltstack(&ss, nil) < 0)
*(int *)0xf1 = 0xf1;
if (sigemptyset(&sigs) != 0)
runtime_throw("sigemptyset");
sigprocmask(SIG_SETMASK, &sigs, nil);
}
uintptr
runtime_memlimit(void)
{
struct rlimit rl;
uintptr used;
if(getrlimit(RLIMIT_AS, &rl) != 0)
return 0;
if(rl.rlim_cur >= 0x7fffffff)
return 0;
// Estimate our VM footprint excluding the heap.
// Not an exact science: use size of binary plus
// some room for thread stacks.
used = (64<<20);
if(used >= rl.rlim_cur)
return 0;
// If there's not at least 16 MB left, we're probably
// not going to be able to do much. Treat as no limit.
rl.rlim_cur -= used;
if(rl.rlim_cur < (16<<20))
return 0;
return rl.rlim_cur - used;
}