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-rw-r--r--gcc-4.8.1/libgo/runtime/lock_sema.c237
1 files changed, 0 insertions, 237 deletions
diff --git a/gcc-4.8.1/libgo/runtime/lock_sema.c b/gcc-4.8.1/libgo/runtime/lock_sema.c
deleted file mode 100644
index 8c4b3973b..000000000
--- a/gcc-4.8.1/libgo/runtime/lock_sema.c
+++ /dev/null
@@ -1,237 +0,0 @@
-// Copyright 2011 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.
-
-// +build darwin netbsd openbsd plan9 windows
-
-#include "runtime.h"
-
-// This implementation depends on OS-specific implementations of
-//
-// uintptr runtime_semacreate(void)
-// Create a semaphore, which will be assigned to m->waitsema.
-// The zero value is treated as absence of any semaphore,
-// so be sure to return a non-zero value.
-//
-// int32 runtime_semasleep(int64 ns)
-// If ns < 0, acquire m->waitsema and return 0.
-// If ns >= 0, try to acquire m->waitsema for at most ns nanoseconds.
-// Return 0 if the semaphore was acquired, -1 if interrupted or timed out.
-//
-// int32 runtime_semawakeup(M *mp)
-// Wake up mp, which is or will soon be sleeping on mp->waitsema.
-//
-
-enum
-{
- LOCKED = 1,
-
- ACTIVE_SPIN = 4,
- ACTIVE_SPIN_CNT = 30,
- PASSIVE_SPIN = 1,
-};
-
-void
-runtime_lock(Lock *l)
-{
- M *m;
- uintptr v;
- uint32 i, spin;
-
- m = runtime_m();
- if(m->locks++ < 0)
- runtime_throw("runtime_lock: lock count");
-
- // Speculative grab for lock.
- if(runtime_casp(&l->waitm, nil, (void*)LOCKED))
- return;
-
- if(m->waitsema == 0)
- m->waitsema = runtime_semacreate();
-
- // On uniprocessor's, no point spinning.
- // On multiprocessors, spin for ACTIVE_SPIN attempts.
- spin = 0;
- if(runtime_ncpu > 1)
- spin = ACTIVE_SPIN;
-
- for(i=0;; i++) {
- v = (uintptr)runtime_atomicloadp(&l->waitm);
- if((v&LOCKED) == 0) {
-unlocked:
- if(runtime_casp(&l->waitm, (void*)v, (void*)(v|LOCKED)))
- return;
- i = 0;
- }
- if(i<spin)
- runtime_procyield(ACTIVE_SPIN_CNT);
- else if(i<spin+PASSIVE_SPIN)
- runtime_osyield();
- else {
- // Someone else has it.
- // l->waitm points to a linked list of M's waiting
- // for this lock, chained through m->nextwaitm.
- // Queue this M.
- for(;;) {
- m->nextwaitm = (void*)(v&~LOCKED);
- if(runtime_casp(&l->waitm, (void*)v, (void*)((uintptr)m|LOCKED)))
- break;
- v = (uintptr)runtime_atomicloadp(&l->waitm);
- if((v&LOCKED) == 0)
- goto unlocked;
- }
- if(v&LOCKED) {
- // Queued. Wait.
- runtime_semasleep(-1);
- i = 0;
- }
- }
- }
-}
-
-void
-runtime_unlock(Lock *l)
-{
- uintptr v;
- M *mp;
-
- if(--runtime_m()->locks < 0)
- runtime_throw("runtime_unlock: lock count");
-
- for(;;) {
- v = (uintptr)runtime_atomicloadp(&l->waitm);
- if(v == LOCKED) {
- if(runtime_casp(&l->waitm, (void*)LOCKED, nil))
- break;
- } else {
- // Other M's are waiting for the lock.
- // Dequeue an M.
- mp = (void*)(v&~LOCKED);
- if(runtime_casp(&l->waitm, (void*)v, mp->nextwaitm)) {
- // Dequeued an M. Wake it.
- runtime_semawakeup(mp);
- break;
- }
- }
- }
-}
-
-// One-time notifications.
-void
-runtime_noteclear(Note *n)
-{
- n->waitm = nil;
-}
-
-void
-runtime_notewakeup(Note *n)
-{
- M *mp;
-
- do
- mp = runtime_atomicloadp(&n->waitm);
- while(!runtime_casp(&n->waitm, mp, (void*)LOCKED));
-
- // Successfully set waitm to LOCKED.
- // What was it before?
- if(mp == nil) {
- // Nothing was waiting. Done.
- } else if(mp == (M*)LOCKED) {
- // Two notewakeups! Not allowed.
- runtime_throw("notewakeup - double wakeup");
- } else {
- // Must be the waiting m. Wake it up.
- runtime_semawakeup(mp);
- }
-}
-
-void
-runtime_notesleep(Note *n)
-{
- M *m;
-
- m = runtime_m();
- if(m->waitsema == 0)
- m->waitsema = runtime_semacreate();
- if(!runtime_casp(&n->waitm, nil, m)) { // must be LOCKED (got wakeup)
- if(n->waitm != (void*)LOCKED)
- runtime_throw("notesleep - waitm out of sync");
- return;
- }
- // Queued. Sleep.
- if(m->profilehz > 0)
- runtime_setprof(false);
- runtime_semasleep(-1);
- if(m->profilehz > 0)
- runtime_setprof(true);
-}
-
-void
-runtime_notetsleep(Note *n, int64 ns)
-{
- M *m;
- M *mp;
- int64 deadline, now;
-
- if(ns < 0) {
- runtime_notesleep(n);
- return;
- }
-
- m = runtime_m();
- if(m->waitsema == 0)
- m->waitsema = runtime_semacreate();
-
- // Register for wakeup on n->waitm.
- if(!runtime_casp(&n->waitm, nil, m)) { // must be LOCKED (got wakeup already)
- if(n->waitm != (void*)LOCKED)
- runtime_throw("notetsleep - waitm out of sync");
- return;
- }
-
- if(m->profilehz > 0)
- runtime_setprof(false);
- deadline = runtime_nanotime() + ns;
- for(;;) {
- // Registered. Sleep.
- if(runtime_semasleep(ns) >= 0) {
- // Acquired semaphore, semawakeup unregistered us.
- // Done.
- if(m->profilehz > 0)
- runtime_setprof(true);
- return;
- }
-
- // Interrupted or timed out. Still registered. Semaphore not acquired.
- now = runtime_nanotime();
- if(now >= deadline)
- break;
-
- // Deadline hasn't arrived. Keep sleeping.
- ns = deadline - now;
- }
-
- if(m->profilehz > 0)
- runtime_setprof(true);
-
- // Deadline arrived. Still registered. Semaphore not acquired.
- // Want to give up and return, but have to unregister first,
- // so that any notewakeup racing with the return does not
- // try to grant us the semaphore when we don't expect it.
- for(;;) {
- mp = runtime_atomicloadp(&n->waitm);
- if(mp == m) {
- // No wakeup yet; unregister if possible.
- if(runtime_casp(&n->waitm, mp, nil))
- return;
- } else if(mp == (M*)LOCKED) {
- // Wakeup happened so semaphore is available.
- // Grab it to avoid getting out of sync.
- if(runtime_semasleep(-1) < 0)
- runtime_throw("runtime: unable to acquire - semaphore out of sync");
- return;
- } else {
- runtime_throw("runtime: unexpected waitm - semaphore out of sync");
- }
- }
-}