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Patch: FYI: updated PR 13212 fix


I'm checking this in.

This has been in the Fedora/Red Hat RPMs for quite a while; I'm
finally putting it on trunk.

This adds a GC API to register the current thread and changes libjava
to take advantage of it.  This is at least partially a backport from
GC 7.  Note that this backport doesn't include the Windows bits, and
in fact only works when pthread_getattr_np and friends are available,
so there's a little hack in gc_ext_config.h and in boehm.cc to account
for this.

This also fixes a regression that showed up with the previous
libgcj_bc patch.  It turns out that patch relied on this one in a
subtle way.

Tom

Index: boehm-gc/ChangeLog
from  Bryce McKinlay  <mckinlay@redhat.com>

	PR libgcj/13212:
	* configure.ac: Check for pthread_getattr_np(). Remove
	GC_PTHREAD_SYM_VERSION detection.
	* include/gc.h (GC_register_my_thread, GC_unregister_my_thread,
	GC_get_thread_stack_base): New declarations.
	* pthread_support.c (GC_register_my_thread, GC_unregister_my_thread,
	GC_get_thread_stack_base): New functions.
	(GC_delete_thread): Don't try to free the first_thread.
	* misc.c (GC_init_inner): Use GC_get_thread_stack_base() if possible.
	(pthread_create_, constr): Removed.
	(pthread_create): Don't rename.
	* include/gc_ext_config.h.in: Rebuilt.
	* include/gc_pthread_redirects.h (pthread_create): Define 
	unconditionally.
	* include/gc_config.h.in: Rebuilt.
	* configure: Rebuilt.

Index: libjava/ChangeLog
from  Bryce McKinlay  <mckinlay@redhat.com>

	* java/lang/natThread.cc (_Jv_AttachCurrentThread): Attach thread
	to GC.
	(_Jv_DetachCurrentThread): Detach thread from GC.
	* include/boehm-gc.h (_Jv_GCAttachThread, _Jv_GCDetachThread):
	Declare.
	* boehm.cc (_Jv_GCAttachThread): New function.
	(_Jv_GCDetachThread): Likewise.

Index: boehm-gc/configure.ac
===================================================================
--- boehm-gc/configure.ac	(revision 116140)
+++ boehm-gc/configure.ac	(working copy)
@@ -1,4 +1,4 @@
-# Copyright (c) 1999, 2000, 2001, 2002, 2003 by Red Hat, Inc. All rights reserved.
+# Copyright (c) 1999, 2000, 2001, 2002, 2003, 2006 by Red Hat, Inc. All rights reserved.
 # Copyright 2004 Nathanael Nerode
 # 
 # THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
@@ -329,6 +329,13 @@
      ;;
 esac
 
+# Checks for pthreads functions
+#
+oldLIBS="$LIBS"
+LIBS="$LIBS $THREADLIBS"
+AC_CHECK_FUNCS([pthread_getattr_np])
+LIBS="$oldLIBS"
+
 # Configuration of machine-dependent code
 #
 # We don't set NO_EXECUTE_PERMISSION by default because gcj (and
@@ -488,25 +495,6 @@
   AC_DEFINE(USE_MMAP, 1, [use MMAP instead of sbrk to get new memory])
 fi
 
-symver=
-case "$target" in
-  *-*-linux* )
-    cat > conftest.c <<EOF
-#include <pthread.h>
-void *tf (void *arg) { (void) arg; return NULL; }
-int main (void) { pthread_t th; pthread_create (&th, NULL, tf, NULL); return 0; }
-EOF
-    if $CC $CFLAGS -pthread -o conftest conftest.c > /dev/null 2>&1; then
-      symver=`readelf -s conftest 2> /dev/null | sed -n '/UND pthread_create@/{s/^.*@//;s/ .*$//;p;q}'`
-    fi
-    rm -f conftest conftest.c
-    ;;
-esac
-if test -n "$symver"; then
-  AC_DEFINE_UNQUOTED(GC_PTHREAD_SYM_VERSION, "$symver", [symbol version of pthread_create])
-fi
-
-
 if test -n "$with_cross_host" &&
    test x"$with_cross_host" != x"no"; then
   toolexecdir='$(exec_prefix)/$(target_noncanonical)'
Index: boehm-gc/include/gc.h
===================================================================
--- boehm-gc/include/gc.h	(revision 116140)
+++ boehm-gc/include/gc.h	(working copy)
@@ -69,7 +69,6 @@
     extern "C" {
 # endif
 
-
 /* Define word and signed_word to be unsigned and signed types of the 	*/
 /* size as char * or void *.  There seems to be no way to do this	*/
 /* even semi-portably.  The following is probably no better/worse 	*/
@@ -912,6 +911,25 @@
 # if defined(PCR) || defined(GC_SOLARIS_THREADS) || \
      defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
    	/* Any flavor of threads except SRC_M3.	*/
+
+/* Register the current thread as a new thread whose stack(s) should    */
+/* be traced by the GC.  						*/
+/* If a platform does not implicitly do so, this must be called before  */
+/* a thread can allocate garbage collected memory, or assign pointers	*/
+/* to the garbage collected heap.  Once registered, a thread will be	*/
+/* stopped during garbage collections.					*/
+GC_API void GC_register_my_thread GC_PROTO((void));
+
+/* Register the current thread, with the indicated stack base, as	*/
+/* a new thread whose stack(s) should be traced by the GC.  If a 	*/
+/* platform does not implicitly do so, this must be called before a	*/
+/* thread can allocate garbage collected memory, or assign pointers	*/
+/* to the garbage collected heap.  Once registered, a thread will be	*/
+/* stopped during garbage collections.					*/
+GC_API void GC_unregister_my_thread GC_PROTO((void));
+
+GC_API GC_PTR GC_get_thread_stack_base GC_PROTO((void));
+
 /* This returns a list of objects, linked through their first		*/
 /* word.  Its use can greatly reduce lock contention problems, since	*/
 /* the allocation lock can be acquired and released many fewer times.	*/
Index: boehm-gc/include/gc_ext_config.h.in
===================================================================
--- boehm-gc/include/gc_ext_config.h.in	(revision 116140)
+++ boehm-gc/include/gc_ext_config.h.in	(working copy)
@@ -4,4 +4,4 @@
 
 #undef THREAD_LOCAL_ALLOC
 
-#undef GC_PTHREAD_SYM_VERSION
+#undef HAVE_PTHREAD_GETATTR_NP
Index: boehm-gc/include/gc_pthread_redirects.h
===================================================================
--- boehm-gc/include/gc_pthread_redirects.h	(revision 116140)
+++ boehm-gc/include/gc_pthread_redirects.h	(working copy)
@@ -68,9 +68,7 @@
 # undef pthread_detach
 #endif
 
-#ifndef GC_PTHREAD_SYM_VERSION
 # define pthread_create GC_pthread_create
-#endif
 # define pthread_join GC_pthread_join
 # define pthread_detach GC_pthread_detach
 
Index: boehm-gc/pthread_support.c
===================================================================
--- boehm-gc/pthread_support.c	(revision 116140)
+++ boehm-gc/pthread_support.c	(working copy)
@@ -602,7 +602,9 @@
     } else {
         prev -> next = p -> next;
     }
-    GC_INTERNAL_FREE(p);
+
+    if (p != &first_thread)
+      GC_INTERNAL_FREE(p);
 }
 
 /* If a thread has been joined, but we have not yet		*/
@@ -1124,6 +1126,107 @@
 
 GC_bool GC_in_thread_creation = FALSE;
 
+GC_PTR GC_get_thread_stack_base()
+{  
+# ifdef HAVE_PTHREAD_GETATTR_NP
+  pthread_t my_pthread;
+  pthread_attr_t attr;
+  ptr_t stack_addr;
+  size_t stack_size;
+  
+  my_pthread = pthread_self();  
+  pthread_getattr_np (my_pthread, &attr);
+  pthread_attr_getstack (&attr, (void **) &stack_addr, &stack_size);
+  pthread_attr_destroy (&attr);
+  
+#   ifdef DEBUG_THREADS
+	GC_printf1("attached thread stack address: 0x%x\n", stack_addr);
+#   endif
+
+#   ifdef STACK_GROWS_DOWN
+      return stack_addr + stack_size;
+#   else
+      return stack_addr - stack_size;
+#   endif
+
+# else
+#   ifdef DEBUG_THREADS
+	GC_printf1("Can not determine stack base for attached thread");
+#   endif
+  return 0;
+# endif
+}
+
+void GC_register_my_thread()
+{
+  GC_thread me;
+  pthread_t my_pthread;
+
+  my_pthread = pthread_self();
+#   ifdef DEBUG_THREADS
+      GC_printf1("Attaching thread 0x%lx\n", my_pthread);
+      GC_printf1("pid = %ld\n", (long) getpid());
+#   endif
+  
+  /* Check to ensure this thread isn't attached already. */
+  LOCK();
+  me = GC_lookup_thread (my_pthread);
+  UNLOCK();
+  if (me != 0)
+    {
+#   ifdef DEBUG_THREADS
+      GC_printf1("Attempt to re-attach known thread 0x%lx\n", my_pthread);
+#   endif
+      return;
+    }
+
+  LOCK();
+  GC_in_thread_creation = TRUE;
+  me = GC_new_thread(my_pthread);
+  GC_in_thread_creation = FALSE;
+
+  me -> flags |= DETACHED;  
+
+#ifdef GC_DARWIN_THREADS
+    me -> stop_info.mach_thread = mach_thread_self();
+#else
+    me -> stack_end = GC_get_thread_stack_base();    
+    if (me -> stack_end == 0)
+      GC_abort("Can not determine stack base for attached thread");
+    
+#   ifdef STACK_GROWS_DOWN
+      me -> stop_info.stack_ptr = me -> stack_end - 0x10;
+#   else
+      me -> stop_info.stack_ptr = me -> stack_end + 0x10;
+#   endif
+#endif
+
+#   ifdef IA64
+      me -> backing_store_end = (ptr_t)
+			(GC_save_regs_in_stack() & ~(GC_page_size - 1));
+      /* This is also < 100% convincing.  We should also read this 	*/
+      /* from /proc, but the hook to do so isn't there yet.		*/
+#   endif /* IA64 */
+
+#   if defined(THREAD_LOCAL_ALLOC) && !defined(DBG_HDRS_ALL)
+        GC_init_thread_local(me);
+#   endif
+  UNLOCK();
+}
+
+void GC_unregister_my_thread()
+{
+  pthread_t my_pthread;
+
+  my_pthread = pthread_self();
+
+#   ifdef DEBUG_THREADS
+      GC_printf1("Detaching thread 0x%lx\n", my_pthread);
+#   endif
+
+  GC_thread_exit_proc (0);
+}
+
 void * GC_start_routine(void * arg)
 {
     int dummy;
@@ -1200,37 +1303,8 @@
     return(result);
 }
 
-#ifdef GC_PTHREAD_SYM_VERSION
-
-/* Force constr to execute prior to main().  */
-static void constr (void) __attribute__ ((constructor));
-
-static int
-(*pthread_create_)(pthread_t *new_thread,
-		   const pthread_attr_t *attr_in,
-		   void * (*thread_execp)(void *), void *arg);
-
-static void
-constr (void)
-{
-  /* Get a pointer to the real pthread_create.  */
-  pthread_create_ = dlvsym (RTLD_NEXT, "pthread_create",
-			    GC_PTHREAD_SYM_VERSION);
-}
-
-#define GC_PTHREAD_CREATE_NAME pthread_create
-#define GC_PTHREAD_REAL_NAME (*pthread_create_)
-
-#else
-
-#define GC_PTHREAD_CREATE_NAME WRAP_FUNC(pthread_create)
-#define GC_PTHREAD_REAL_NAME REAL_FUNC(pthread_create)
-
-#endif
-
-
 int
-GC_PTHREAD_CREATE_NAME(pthread_t *new_thread,
+WRAP_FUNC(pthread_create)(pthread_t *new_thread,
 		  const pthread_attr_t *attr,
                   void *(*start_routine)(void *), void *arg)
 {
@@ -1291,7 +1365,7 @@
 		   pthread_self());
 #   endif
 
-    result = GC_PTHREAD_REAL_NAME(new_thread, attr, GC_start_routine, si);
+    result = REAL_FUNC(pthread_create)(new_thread, attr, GC_start_routine, si);
 
 #   ifdef DEBUG_THREADS
         GC_printf1("Started thread 0x%X\n", *new_thread);
Index: boehm-gc/misc.c
===================================================================
--- boehm-gc/misc.c	(revision 116140)
+++ boehm-gc/misc.c	(working copy)
@@ -674,7 +674,13 @@
 #   if !defined(THREADS) || defined(GC_PTHREADS) || defined(GC_WIN32_THREADS) \
 	|| defined(GC_SOLARIS_THREADS)
       if (GC_stackbottom == 0) {
-	GC_stackbottom = GC_get_stack_base();
+        # ifdef GC_PTHREADS
+	/* Use thread_stack_base if available, as GC could be initialized from
+	   a thread that is not the "main" thread.  */
+	GC_stackbottom = GC_get_thread_stack_base();
+	# endif
+	if (GC_stackbottom == 0)
+	  GC_stackbottom = GC_get_stack_base();
 #       if (defined(LINUX) || defined(HPUX)) && defined(IA64)
 	  GC_register_stackbottom = GC_get_register_stack_base();
 #       endif
Index: libjava/boehm.cc
===================================================================
--- libjava/boehm.cc	(revision 116169)
+++ libjava/boehm.cc	(working copy)
@@ -695,3 +695,21 @@
   GC_resume_thread (_Jv_GetPlatformThreadID (thread));
 #endif
 }
+
+void
+_Jv_GCAttachThread ()
+{
+  // The registration interface is only defined on posixy systems and
+  // only actually works if pthread_getattr_np is defined.
+#ifdef HAVE_PTHREAD_GETATTR_NP
+  GC_register_my_thread ();
+#endif
+}
+
+void
+_Jv_GCDetachThread ()
+{
+#ifdef HAVE_PTHREAD_GETATTR_NP
+  GC_unregister_my_thread ();
+#endif
+}
Index: libjava/java/lang/natThread.cc
===================================================================
--- libjava/java/lang/natThread.cc	(revision 116169)
+++ libjava/java/lang/natThread.cc	(working copy)
@@ -410,7 +410,8 @@
 }
 
 // Attach the current native thread to an existing (but unstarted) Thread 
-// object. Returns -1 on failure, 0 upon success.
+// object. Does not register thread with the garbage collector.
+// Returns -1 on failure, 0 upon success.
 jint
 _Jv_AttachCurrentThread(java::lang::Thread* thread)
 {
@@ -427,6 +428,8 @@
 java::lang::Thread*
 _Jv_AttachCurrentThread(jstring name, java::lang::ThreadGroup* group)
 {
+  // Register thread with GC before attempting any allocations.
+  _Jv_GCAttachThread ();
   java::lang::Thread *thread = _Jv_ThreadCurrent ();
   if (thread != NULL)
     return thread;
@@ -461,6 +464,7 @@
     return -1;
 
   _Jv_ThreadUnRegister ();
+  _Jv_GCDetachThread ();
   // Release the monitors.
   t->finish_ ();
 
Index: libjava/include/boehm-gc.h
===================================================================
--- libjava/include/boehm-gc.h	(revision 116169)
+++ libjava/include/boehm-gc.h	(working copy)
@@ -80,6 +80,10 @@
 
 #endif /* LIBGCJ_GC_DEBUG */
 
+void _Jv_GCAttachThread ();
+
+void _Jv_GCDetachThread ();
+
 // _Jv_AllocBytes (jsize size) should go here, too.  But clients don't
 // usually include this header.
 


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