implement futex.cc

diff --git a/futex.cc b/futex.cc
new file mode 100644 (file)
index 0000000..64ec6b4
--- /dev/null
+++ b/futex.cc
@@ -0,0 +1,70 @@
+// futex -*- C++ -*-
+
+// Copyright (C) 2015-2019 Free Software Foundation, Inc.
+//
+// This is a reimplementation of libstdc++-v3/src/c++11/futex.cc. 
+
+#include <bits/atomic_futex.h>
+#ifdef _GLIBCXX_HAS_GTHREADS
+#if defined(_GLIBCXX_HAVE_LINUX_FUTEX) && ATOMIC_INT_LOCK_FREE > 1
+#include <chrono>
+#include <climits>
+#include <syscall.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <errno.h>
+#include <debug/debug.h>
+
+#include "model.h"
+#include "execution.h"
+#include "mutex.h"
+#include <condition_variable>
+
+// Constants for the wait/wake futex syscall operations
+const unsigned futex_wait_op = 0;
+const unsigned futex_wake_op = 1;
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+       bool
+       __atomic_futex_unsigned_base::_M_futex_wait_until(unsigned *__addr,
+               unsigned __val,
+               bool __has_timeout, chrono::seconds __s, chrono::nanoseconds __ns)
+       {
+               // do nothing if the two values are not equal
+               if ( *__addr != __val ) {
+                       return true;
+               }
+
+               // if a timeout is specified, return immedialy. Letting the scheduler decide how long this thread will wait.  
+               if (__has_timeout) {
+                       return true;
+               }
+
+               ModelExecution *execution = model->get_execution();
+
+               cdsc::condition_variable *v = new cdsc::condition_variable();
+               cdsc::mutex *m = new cdsc::mutex();
+
+               execution->cond_map.put( (pthread_cond_t *) __addr, v);
+               execution->mutex_map.put( (pthread_mutex_t *) __addr, m);
+
+               v->wait(*m);
+               return true;
+       }
+
+       void
+       __atomic_futex_unsigned_base::_M_futex_notify_all(unsigned* __addr)
+       {
+               // INT_MAX wakes all the waiters at the address __addr
+               ModelExecution *execution = model->get_execution();
+               cdsc::condition_variable *v = execution->cond_map.get( (pthread_cond_t *) __addr);
+               v->notify_all();
+       }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+}
+#endif // defined(_GLIBCXX_HAVE_LINUX_FUTEX) && ATOMIC_INT_LOCK_FREE > 1
+#endif // _GLIBCXX_HAS_GTHREADS