runtime, sync: use __atomic intrinsics instead of __sync

    
    GCC has supported the __atomic intrinsics since 4.7.  They are better
    than the __sync intrinsics in that they specify a memory model and,
    more importantly for our purposes, they are reliably implemented
    either in the compiler or in libatomic.
    
    Fixes https://gcc.gnu.org/PR52084
    
    Reviewed-on: https://go-review.googlesource.com/c/160820

From-SVN: r268458

2 files changed, 1 insertions, 176 deletions

diff --git a/libgo/runtime/runtime.h b/libgo/runtime/runtime.h
index 3bb1e55..5da34fb 100644
--- a/libgo/runtime/runtime.h
+++ b/libgo/runtime/runtime.h
@@ -276,22 +276,8 @@ int32	runtime_timediv(int64, int32, int32*)
 int32	runtime_round2(int32 x); // round x up to a power of 2.
 
 // atomic operations
-#define runtime_cas(pval, old, new) __sync_bool_compare_and_swap (pval, old, new)
-#define runtime_cas64(pval, old, new) __sync_bool_compare_and_swap (pval, old, new)
-#define runtime_casp(pval, old, new) __sync_bool_compare_and_swap (pval, old, new)
-// Don't confuse with XADD x86 instruction,
-// this one is actually 'addx', that is, add-and-fetch.
-#define runtime_xadd(p, v) __sync_add_and_fetch (p, v)
-#define runtime_xadd64(p, v) __sync_add_and_fetch (p, v)
-#define runtime_xchg(p, v) __atomic_exchange_n (p, v, __ATOMIC_SEQ_CST)
-#define runtime_xchg64(p, v) __atomic_exchange_n (p, v, __ATOMIC_SEQ_CST)
-#define runtime_xchgp(p, v) __atomic_exchange_n (p, v, __ATOMIC_SEQ_CST)
+#define runtime_xadd(p, v) __atomic_add_fetch (p, v, __ATOMIC_SEQ_CST)
 #define runtime_atomicload(p) __atomic_load_n (p, __ATOMIC_SEQ_CST)
-#define runtime_atomicstore(p, v) __atomic_store_n (p, v, __ATOMIC_SEQ_CST)
-#define runtime_atomicstore64(p, v) __atomic_store_n (p, v, __ATOMIC_SEQ_CST)
-#define runtime_atomicload64(p) __atomic_load_n (p, __ATOMIC_SEQ_CST)
-#define runtime_atomicloadp(p) __atomic_load_n (p, __ATOMIC_SEQ_CST)
-#define runtime_atomicstorep(p, v) __atomic_store_n (p, v, __ATOMIC_SEQ_CST)
 
 void runtime_setg(G*)
   __asm__ (GOSYM_PREFIX "runtime.setg");
diff --git a/libgo/runtime/thread.c b/libgo/runtime/thread.c
deleted file mode 100644
index 83ee006..0000000
--- a/libgo/runtime/thread.c
+++ /dev/null
@@ -1,161 +0,0 @@
-// 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
-
-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;
-}