maria-developers team mailing list archive

[Michael Widenius <monty@xxxxxxxxxxxx>]

Hi!

>>>>> "knielsen" == knielsen  <knielsen@xxxxxxxxxxxxxxx> writes:

knielsen> (Some versions of GCC implement struct_var = struct_var using
knielsen> memcpy(), which violates specs for memcpy() (not allowed for
knielsen> overlapping source and destination).

knielsen> GCC bug 19410: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19410

knielsen> === modified file 'sql/sql_select.cc'
knielsen> ---
knielsen>  sql/sql_select.cc |   13 +++++++++++--
knielsen>  1 file changed, 11 insertions(+), 2 deletions(-)

knielsen> Index: sql/sql_select.cc
knielsen> ===================================================================
knielsen> --- sql/sql_select.cc.orig	2009-04-07 13:40:36.000000000 +0200
knielsen> +++ sql/sql_select.cc	2009-04-07 13:42:10.000000000 +0200
knielsen> @@ -1994,8 +1994,17 @@ JOIN::exec()
knielsen>  				     tmp_fields_list2, tmp_all_fields2, 
knielsen>  				     fields_list.elements, tmp_all_fields1))
knielsen>  	  DBUG_VOID_RETURN;
knielsen> -	curr_join->tmp_fields_list2= tmp_fields_list2;
knielsen> -	curr_join->tmp_all_fields2= tmp_all_fields2;
knielsen> +#ifdef HAVE_purify
knielsen> +        /*
knielsen> +          Some GCCs use memcpy() for struct assignment, even for x=x.
knielsen> +          GCC bug 19410: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19410
knielsen> +        */
knielsen> +        if (curr_join != this)
knielsen> +#endif
knielsen> +        {
knielsen> +          curr_join->tmp_fields_list2= tmp_fields_list2;
knielsen> +          curr_join->tmp_all_fields2= tmp_all_fields2;
knielsen> +        }
knielsen>        }
knielsen>        curr_fields_list= &curr_join->tmp_fields_list2;
knielsen>        curr_all_fields= &curr_join->tmp_all_fields2;

ok to push.

I think this is actually something that should be fixed in valgrind;
Copying over itself shouldn't give a warning.
(Or at least, one should be able to disable it)

Regards,
Monty