2001-04-04 Hans Boehm <hans_boehm@hp.com>

	* finalize.c:
	- Accomodate finalization requests for static objects.
	  (Will be required by hash synchronization.  May be needed
	  in some configurations now.)

	* gc_priv.h:
	- Define MIN_WORDS.  All allocation requests are rounded
	  up to at least this size.  Removes a subtle assumption that
	  Java objects have a 2 word header.

	* gcconfig.h:
	- Adjust Linux/IA64 configuration for non-ancient kernels.
	  (Necessary fix for IA64.)

	* linux_threads.c:
	- Fix syntax error in currently unused code.  Will be needed
	  for Linux/PA-RISC.

	* malloc.c:
	- Handle MIN_WORDS.

	* misc.c:
	- Handle MIN_WORDS.
	- Change stack cleaning code to typically clear about one tenth
	  the memory it used to in the threads configuration.  Occasionally
	  still clear more.  (This is really a fix for a long-standing
	  and fairly significant performance bug with threads.)

	* os_dep.c:
	- Fix the code for finding the beginning of the data segment under
	  Linux.  I believe this is necessary for some IA64 Linux
	  distributions.  It will also helo other platforms, though those
	  may additionally require a gcconfig.h adjustment.  (This basically
	  works around the absence of a data_start or __data_start
	  definition in glibc.)

	* test.c:
	- Handle rounding due to MIN_WORDS.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@41102 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 21 insertions, 4 deletions

diff --git a/boehm-gc/os_dep.c b/boehm-gc/os_dep.c
index 87f84e7bccd..a192d35a21a 100644
--- a/boehm-gc/os_dep.c
+++ b/boehm-gc/os_dep.c
@@ -144,20 +144,37 @@
 #endif
 
 #if defined(SEARCH_FOR_DATA_START)
-  /* The following doesn't work if the GC is in a dynamic library.	*/
   /* The I386 case can be handled without a search.  The Alpha case	*/
   /* used to be handled differently as well, but the rules changed	*/
   /* for recent Linux versions.  This seems to be the easiest way to	*/
   /* cover all versions.						*/
-  ptr_t GC_data_start;
 
-  extern char * GC_copyright[];  /* Any data symbol would do. */
+# ifdef LINUX
+#   pragma weak __data_start
+    extern int __data_start;
+#   pragma weak data_start
+    extern int data_start;
+# endif /* LINUX */
+  extern int _end;
+
+  ptr_t GC_data_start;
 
   void GC_init_linux_data_start()
   {
     extern ptr_t GC_find_limit();
 
-    GC_data_start = GC_find_limit((ptr_t)GC_copyright, FALSE);
+#   ifdef LINUX
+      /* Try the easy approaches first:	*/
+      if (&__data_start != 0) {
+	  GC_data_start = (ptr_t)(&__data_start);
+	  return;
+      }
+      if (&data_start != 0) {
+	  GC_data_start = (ptr_t)(&data_start);
+	  return;
+      }
+#   endif /* LINUX */
+    GC_data_start = GC_find_limit((ptr_t)(&_end), FALSE);
   }
 #endif