2010-03-12 Ivan Maidanski <ivmai@mail.ru>

	* doc/README.macros (USE_GET_STACKBASE_FOR_MAIN): Document.
	* os_dep.c (GC_get_main_stack_base): Recognize
	USE_GET_STACKBASE_FOR_MAIN (only if THREADS and LINUX_STACKBOTTOM)
	and use GC_get_stack_base() in this case.

ChangeLog

@@ -1,3 +1,10 @@
+2010-03-12  Ivan Maidanski <ivmai@mail.ru>
+
+	* doc/README.macros (USE_GET_STACKBASE_FOR_MAIN): Document.
+	* os_dep.c (GC_get_main_stack_base): Recognize
+	USE_GET_STACKBASE_FOR_MAIN (only if THREADS and LINUX_STACKBOTTOM)
+	and use GC_get_stack_base() in this case.
+
 2010-03-05  Ivan Maidanski <ivmai@mail.ru> (really Burkhard Linke)
 
 	* os_dep.c (GC_get_stack_base): Add LOCK/UNLOCK() (since

doc/README.macros

@@ -511,3 +511,7 @@ UNICODE (Win32 only)    Use the Unicode variant ('W') of the Win32 API instead
   of ANSI/ASCII one ('A').  Useful for WinCE.
 
 PLATFORM_ANDROID        Compile for Android NDK platform.
+
+USE_GET_STACKBASE_FOR_MAIN (Linux only)  Use pthread_attr_getstack() instead
+of __libc_stack_end for getting the primordial thread stack base (useful if
+the client modifies the program's address space).

os_dep.c

@@ -1163,6 +1163,13 @@ ptr_t GC_get_main_stack_base(void)
 #          endif
 #       endif /* HEURISTIC1 */
 #       ifdef LINUX_STACKBOTTOM
+#          if defined(THREADS) && defined(USE_GET_STACKBASE_FOR_MAIN)
+             {
+               struct GC_stack_base sb;
+               if (GC_get_stack_base(&sb) == GC_SUCCESS)
+                 return (ptr_t)sb.mem_base;
+             }
+#          endif
            result = GC_linux_stack_base();
 #       endif
 #       ifdef FREEBSD_STACKBOTTOM