From: Simon Marlow <marlowsd@gmail.com>
Date: Fri, 16 Jan 2009 11:43:39 +0000 (+0000)
Subject: UNDO: Always check the result of pthread_mutex_lock() and pthread_mutex_unlock().
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=b2d4af35427f9b195ba9987f5ce6b48fb2a5de64

UNDO: Always check the result of pthread_mutex_lock() and pthread_mutex_unlock().
This patch caused problems on Mac OS X, undoing until we can do it better.

rolling back:

Sun Jan  4 19:24:43 GMT 2009  Matthias Kilian <kili@outback.escape.de>
  * Always check the result of pthread_mutex_lock() and pthread_mutex_unlock().

  Don't check pthread_mutex_*lock() only on Linux and/or only if DEBUG
  is defined. The return values of those functions are well defined
  and should be supported on all operation systems with pthreads. The
  checks are cheap enough to do them even in the default build (without
  -DDEBUG).

  While here, recycle an unused macro ASSERT_LOCK_NOTHELD, and let
  the debugBelch part enabled with -DLOCK_DEBUG work independently
  of -DDEBUG.


    M ./includes/OSThreads.h -30 +10
---

diff --git a/includes/OSThreads.h b/includes/OSThreads.h
index fd57f56..d79b9af 100644
--- a/includes/OSThreads.h
+++ b/includes/OSThreads.h
@@ -23,7 +23,6 @@
 #else
 
 #include <pthread.h>
-#include <errno.h>
 
 typedef pthread_cond_t  Condition;
 typedef pthread_mutex_t Mutex;
@@ -35,27 +34,48 @@ typedef pthread_key_t   ThreadLocalKey;
 #define INIT_COND_VAR       PTHREAD_COND_INITIALIZER
 
 #ifdef LOCK_DEBUG
-#define LOCK_DEBUG_BELCH(what, mutex) \
-  debugBelch("%s(0x%p) %s %d\n", what, mutex, __FILE__, __LINE__)
-#else
-#define LOCK_DEBUG_BELCH(what, mutex) /* nothing */
-#endif
 
-/* Always check the result of lock and unlock. */
 #define ACQUIRE_LOCK(mutex) \
-  LOCK_DEBUG_BELCH("ACQUIRE_LOCK", mutex); \
+  debugBelch("ACQUIRE_LOCK(0x%p) %s %d\n", mutex,__FILE__,__LINE__); \
+  pthread_mutex_lock(mutex)
+#define RELEASE_LOCK(mutex) \
+  debugBelch("RELEASE_LOCK(0x%p) %s %d\n", mutex,__FILE__,__LINE__); \
+  pthread_mutex_unlock(mutex)
+#define ASSERT_LOCK_HELD(mutex) /* nothing */
+
+#elif defined(DEBUG) && defined(linux_HOST_OS)
+#include <errno.h>
+/* 
+ * On Linux, we can use extensions to determine whether we already
+ * hold a lock or not, which is useful for debugging.
+ */
+#define ACQUIRE_LOCK(mutex) \
   if (pthread_mutex_lock(mutex) == EDEADLK) { \
     barf("multiple ACQUIRE_LOCK: %s %d", __FILE__,__LINE__); \
   }
-
 #define RELEASE_LOCK(mutex) \
-  LOCK_DEBUG_BELCH("RELEASE_LOCK", mutex); \
   if (pthread_mutex_unlock(mutex) != 0) { \
     barf("RELEASE_LOCK: I do not own this lock: %s %d", __FILE__,__LINE__); \
   }
 
 #define ASSERT_LOCK_HELD(mutex) ASSERT(pthread_mutex_lock(mutex) == EDEADLK)
 
+#define ASSERT_LOCK_NOTHELD(mutex)		\
+  if (pthread_mutex_lock(mutex) != EDEADLK) {	\
+     pthread_mutex_unlock(mutex);		\
+  } else {					\
+    ASSERT(0);					\
+  }
+
+
+#else
+
+#define ACQUIRE_LOCK(mutex) pthread_mutex_lock(mutex)
+#define RELEASE_LOCK(mutex) pthread_mutex_unlock(mutex)
+#define ASSERT_LOCK_HELD(mutex) /* nothing */
+
+#endif
+
 #endif // CMINUSMINUS
 
 # elif defined(HAVE_WINDOWS_H)