Don't relax org or align. They change size as the relaxation happens, but they

[oota-llvm.git] / lib / Support / Mutex.cpp

diff --git a/lib/Support/Mutex.cpp b/lib/Support/Mutex.cpp
index 6271797da4785a4ee73280988429c5ed28a2fbdd..488868febe409d1c9d3da1b8717732ba8122f9e3 100644 (file)
--- a/lib/Support/Mutex.cpp
+++ b/lib/Support/Mutex.cpp
@@ -1,24 +1,156 @@
-//===-- Support/Lock.cpp - Platform-agnostic mutual exclusion -------------===//
-// 
+//===- Mutex.cpp - Mutual Exclusion Lock ------------------------*- C++ -*-===//
+//
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-// 
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
 //===----------------------------------------------------------------------===//
 //
-// Implementation of various methods supporting platform-agnostic lock
-// abstraction. See Support/Lock.h for details.
+// This file implements the llvm::sys::Mutex class.
 //
 //===----------------------------------------------------------------------===//
 
-#include "Support/Lock.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Mutex.h"
 
-using namespace llvm;
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only TRULY operating system
+//===          independent code.
+//===----------------------------------------------------------------------===//
 
-Lock Lock::create () {
-  // Currently we only support creating POSIX pthread_mutex_t locks.
-  // In the future we might want to construct different kinds of locks
-  // based on what OS is running.
-  return POSIXLock ();
+#if !defined(ENABLE_THREADS) || ENABLE_THREADS == 0
+// Define all methods as no-ops if threading is explicitly disabled
+namespace llvm {
+using namespace sys;
+MutexImpl::MutexImpl( bool recursive) { }
+MutexImpl::~MutexImpl() { }
+bool MutexImpl::acquire() { return true; }
+bool MutexImpl::release() { return true; }
+bool MutexImpl::tryacquire() { return true; }
 }
+#else
+
+#if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_MUTEX_LOCK)
+
+#include <cassert>
+#include <pthread.h>
+#include <stdlib.h>
+
+namespace llvm {
+using namespace sys;
+
+
+// This variable is useful for situations where the pthread library has been
+// compiled with weak linkage for its interface symbols. This allows the
+// threading support to be turned off by simply not linking against -lpthread.
+// In that situation, the value of pthread_mutex_init will be 0 and
+// consequently pthread_enabled will be false. In such situations, all the
+// pthread operations become no-ops and the functions all return false. If
+// pthread_mutex_init does have an address, then mutex support is enabled.
+// Note: all LLVM tools will link against -lpthread if its available since it
+//       is configured into the LIBS variable.
+// Note: this line of code generates a warning if pthread_mutex_init is not
+//       declared with weak linkage. It's safe to ignore the warning.
+static const bool pthread_enabled = true;
+
+// Construct a Mutex using pthread calls
+MutexImpl::MutexImpl( bool recursive)
+  : data_(0)
+{
+  if (pthread_enabled)
+  {
+    // Declare the pthread_mutex data structures
+    pthread_mutex_t* mutex =
+      static_cast<pthread_mutex_t*>(malloc(sizeof(pthread_mutex_t)));
+    pthread_mutexattr_t attr;
+
+    // Initialize the mutex attributes
+    int errorcode = pthread_mutexattr_init(&attr);
+    assert(errorcode == 0);
+
+    // Initialize the mutex as a recursive mutex, if requested, or normal
+    // otherwise.
+    int kind = ( recursive  ? PTHREAD_MUTEX_RECURSIVE : PTHREAD_MUTEX_NORMAL );
+    errorcode = pthread_mutexattr_settype(&attr, kind);
+    assert(errorcode == 0);
+
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__DragonFly__)
+    // Make it a process local mutex
+    errorcode = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE);
+#endif
+
+    // Initialize the mutex
+    errorcode = pthread_mutex_init(mutex, &attr);
+    assert(errorcode == 0);
+
+    // Destroy the attributes
+    errorcode = pthread_mutexattr_destroy(&attr);
+    assert(errorcode == 0);
+
+    // Assign the data member
+    data_ = mutex;
+  }
+}
+
+// Destruct a Mutex
+MutexImpl::~MutexImpl()
+{
+  if (pthread_enabled)
+  {
+    pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
+    assert(mutex != 0);
+    pthread_mutex_destroy(mutex);
+    free(mutex);
+  }
+}
+
+bool
+MutexImpl::acquire()
+{
+  if (pthread_enabled)
+  {
+    pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
+    assert(mutex != 0);
+
+    int errorcode = pthread_mutex_lock(mutex);
+    return errorcode == 0;
+  } else return false;
+}
+
+bool
+MutexImpl::release()
+{
+  if (pthread_enabled)
+  {
+    pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
+    assert(mutex != 0);
+
+    int errorcode = pthread_mutex_unlock(mutex);
+    return errorcode == 0;
+  } else return false;
+}
+
+bool
+MutexImpl::tryacquire()
+{
+  if (pthread_enabled)
+  {
+    pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
+    assert(mutex != 0);
+
+    int errorcode = pthread_mutex_trylock(mutex);
+    return errorcode == 0;
+  } else return false;
+}
+
+}
+
+#elif defined(LLVM_ON_UNIX)
+#include "Unix/Mutex.inc"
+#elif defined( LLVM_ON_WIN32)
+#include "Windows/Mutex.inc"
+#else
+#warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in System/Mutex.cpp
+#endif
+#endif