svn commit: r227369 - head/bin/sh
Stefan Farfeleder
stefanf at FreeBSD.org
Wed Nov 9 08:36:00 UTC 2011
On Tue, Nov 08, 2011 at 11:54:39PM +0000, Jilles Tjoelker wrote:
> Author: jilles
> Date: Tue Nov 8 23:54:39 2011
> New Revision: 227369
> URL: http://svn.freebsd.org/changeset/base/227369
>
> Log:
> sh: Remove undefined behaviour due to overflow in +/-/* in arithmetic.
>
> With i386 base gcc and i386 base clang, arith_yacc.o remains unchanged.
>
> Modified:
> head/bin/sh/arith_yacc.c
>
> Modified: head/bin/sh/arith_yacc.c
> ==============================================================================
> --- head/bin/sh/arith_yacc.c Tue Nov 8 23:44:26 2011 (r227368)
> +++ head/bin/sh/arith_yacc.c Tue Nov 8 23:54:39 2011 (r227369)
> @@ -131,11 +131,11 @@ static arith_t do_binop(int op, arith_t
> yyerror("divide error");
> return op == ARITH_REM ? a % b : a / b;
> case ARITH_MUL:
> - return a * b;
> + return (uintmax_t)a * (uintmax_t)b;
> case ARITH_ADD:
> - return a + b;
> + return (uintmax_t)a + (uintmax_t)b;
> case ARITH_SUB:
> - return a - b;
> + return (uintmax_t)a - (uintmax_t)b;
> case ARITH_LSHIFT:
> return a << b;
> case ARITH_RSHIFT:
>
Isn't the behaviour undefined too when you convert an out-of-range
uintmax_t value back into an intmax_t value?
Stefan
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