2010-07-29 Ivan Maidanski <ivmai@mail.ru> (with input from NIIBE Yutaka)

	* pthread_start.c: New file.
	* CMakeLists.txt (SRC): Add pthread_start.c.
	* Makefile.am (libgc_la_SOURCES): Ditto.
	* Makefile.direct (CSRCS): Ditto.
	* Makefile.direct (OBJS): Add pthread_start.obj.
	* extra/gc.c: Add a comment; include pthread_start.c.
	* pthread_support.c (start_info): Move the struct definition down
	closer to its usage.
	* pthread_support.c (GC_thread_exit_proc): Replace STATIC with
	GC_INNER.
	* pthread_support.c (GC_inner_start_routine): Move to the
	definition to pthread_start.c; leave only the prototype; remove
	STATIC.
	* pthread_support.c (GC_start_rtn_prepare_thread): New function
	(contains parts of the original GC_inner_start_routine).
	* Makefile.in: Regenerate.
	* configure: Ditto.

1 files changed, 70 insertions, 0 deletions

diff --git a/pthread_start.c b/pthread_start.c
new file mode 100644
index 00000000..a6e1f72d
--- /dev/null
+++ b/pthread_start.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
+ * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
+ * Copyright (c) 1998 by Fergus Henderson.  All rights reserved.
+ * Copyright (c) 2000-2010 by Hewlett-Packard Development Company.
+ * All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+
+/* We want to make sure that GC_thread_exit_proc() is unconditionally   */
+/* invoked, even if the client is not compiled with -fexceptions, but   */
+/* the GC is.  The workaround is to put GC_inner_start_routine() in its */
+/* own file (pthread_start.c), and undefine __EXCEPTIONS in the GCC     */
+/* case at the top of the file.  FIXME: it's still unclear whether this */
+/* will actually cause the exit handler to be invoked last when         */
+/* thread_exit is called (and if -fexceptions is used).                 */
+#if defined(__GNUC__) && defined(__linux__)
+  /* We undefine __EXCEPTIONS to avoid using GCC __cleanup__ attribute. */
+  /* The current NPTL implementation of pthread_cleanup_push uses       */
+  /* __cleanup__ attribute when __EXCEPTIONS is defined (-fexceptions). */
+  /* The stack unwinding and cleanup with __cleanup__ attributes work   */
+  /* correctly when everything is compiled with -fexceptions, but it is */
+  /* not the requirement for this library clients to use -fexceptions   */
+  /* everywhere.  With __EXCEPTIONS undefined, the cleanup routines are */
+  /* registered with __pthread_register_cancel thus should work anyway. */
+# undef __EXCEPTIONS
+#endif
+
+#include "private/pthread_support.h"
+
+#if defined(GC_PTHREADS) && !defined(GC_WIN32_THREADS)
+
+#include <pthread.h>
+#include <sched.h>
+
+GC_INNER void * GC_start_rtn_prepare_thread(void *(**pstart)(void *),
+                                        void **pstart_arg,
+                                        struct GC_stack_base *sb, void *arg);
+GC_INNER void GC_thread_exit_proc(void *arg);
+                                        /* defined in pthread_support.c */
+
+/* Invoked from GC_start_routine(). */
+void * GC_CALLBACK GC_inner_start_routine(struct GC_stack_base *sb, void *arg)
+{
+  void * (*start)(void *);
+  void * start_arg;
+  void * result;
+  GC_thread me = GC_start_rtn_prepare_thread(&start, &start_arg, sb, arg);
+
+  pthread_cleanup_push(GC_thread_exit_proc, 0);
+  result = (*start)(start_arg);
+# ifdef DEBUG_THREADS
+    GC_printf("Finishing thread 0x%x\n", (unsigned)pthread_self());
+# endif
+  me -> status = result;
+  pthread_cleanup_pop(1);
+  /* Cleanup acquires lock, ensuring that we can't exit while   */
+  /* a collection that thinks we're alive is trying to stop us. */
+  return result;
+}
+
+#endif /* GC_PTHREADS */