[Gc] RE: Interface between gc and clients to control conservative scan

Andrew Haley aph at redhat.com
Fri Apr 21 10:46:20 PDT 2006


Here's what I've been using.

Is this OK?

Thanks,
Andrew.


2006-04-21  Andrew Haley  <aph at redhat.com>

	* include/gc.h (GC_register_has_static_roots_callback): Declare.
	* dyn_load.c (GC_has_static_roots): Declare.
	(GC_register_dynlib_callback): Call GC_has_static_roots.

Index: boehm-gc/include/gc.h
===================================================================
--- boehm-gc/include/gc.h	(revision 113114)
+++ boehm-gc/include/gc.h	(working copy)
@@ -925,6 +925,15 @@
 
 #endif /* THREADS && !SRC_M3 */
 
+/* Register a callback to control the scanning of dynamic libraries.
+   When the GC scans the static data of a dynamic library, it will
+   first call a user-supplied routine with filename of the library and
+   the address and length of the memory region.  This routine should
+   return nonzero if that region should be scanned.  */
+GC_API void GC_register_has_static_roots_callback 
+  (int (*callback)(const char *, void *, size_t));
+
+
 #if defined(GC_WIN32_THREADS) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)
 # include <windows.h>
 
Index: boehm-gc/dyn_load.c
===================================================================
--- boehm-gc/dyn_load.c	(revision 113114)
+++ boehm-gc/dyn_load.c	(working copy)
@@ -119,6 +119,17 @@
 #    endif
 #  endif
 
+/* An user-supplied routine that is called to dtermine if a DSO must
+   be scanned by the gc.  */
+static int (*GC_has_static_roots)(const char *, void *, size_t);
+/* Register the routine.  */
+void
+GC_register_has_static_roots_callback 
+  (int (*callback)(const char *, void *, size_t))
+{
+  GC_has_static_roots = callback;
+}
+
 #if defined(SUNOS5DL) && !defined(USE_PROC_FOR_LIBRARIES)
 
 #ifdef LINT
@@ -371,7 +382,7 @@
 {
   return FALSE;
 }
-  
+
 # define HAVE_REGISTER_MAIN_STATIC_DATA
 
 #endif /* USE_PROC_FOR_LIBRARIES */
@@ -411,6 +422,11 @@
 	{
 	  if( !(p->p_flags & PF_W) ) break;
 	  start = ((char *)(p->p_vaddr)) + info->dlpi_addr;
+
+	  if (GC_has_static_roots 
+	      && !GC_has_static_roots(info->dlpi_name, start, p->p_memsz))
+	    break;
+
 	  GC_add_roots_inner(start, start + p->p_memsz, TRUE);
 	}
       break;


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