Interface between gc and clients to control conservative scan

[Hans Boehm]

Thanks.

That looks good to me.  I'll merge it into at least my 7.0 tree.

Hans

On Fri, 21 Apr 2006, Andrew Haley wrote:

> Here's what I've been using.
>
> Is this OK?
>
> Thanks,
> Andrew.
>
>
> 2006-04-21  Andrew Haley  <aph@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;
>