Re: [PATCH/RFA]: New configure option disabling target optimization

[Jeff Johnston <jjohnstn at redhat dot com>]

I think there is a simpler answer.  Just remove the setting of the -O2 
flag in configure.host.  The optimization flag gets set by default in 
the top-level so there is no need to duplicate it.  That way you could 
just use CFLAG settings to accomplish what you want.

Try the attached patch.

-- Jeff J.

On 20/10/09 06:28 AM, Corinna Vinschen wrote:
> Hi,
>
>
> when building newlib, there's a statement in configure.host which always
> adds some sort of optimization to NEWLIB_CFLAGS.  Maybe I'm just dense,
> but I haven't found a way to disable the generation of the optimization
> flags using configure or make, without having to enter a new
> NEWLIB_CFLAGS value, which in turn requires to enter the full rat tail
> of target specific options.  For Cygwin, this means for instance:
>
>    make NEWLIB_CFLAGS='-DHAVE_OPENDIR -DHAVE_RENAME -DSIGNAL_PROVIDED -D_COMPILING_NEWLIB -DHAVE_BLKSIZE -DHAVE_FCNTL -DMALLOC_PROVIDED -fno-builtin'
>
> That's pretty cumbersome.  I'm constantly building the Cygwin/newlib
> source tree for debuggging using `CFLAGS=-g', and for debugging any
> optimization is just in the way.
>
> Therefore I'd like to propose a patch to add a configure option to
> disable this automatic optimization option in configure.host.  Would
> something like this be ok to apply, or is there already some easier way
> to accomplish the same which I just didn't notice?
>
>
> Thanks,
> Corinna
>
>
> 	* acinclude.m4: Add --disable-target-optimization option.
> 	* configure.host: Skip target optimization setting if
> 	--disable-target-optimization has been specified.
>
>
> Index: acinclude.m4
> ===================================================================
> RCS file: /cvs/src/src/newlib/acinclude.m4,v
> retrieving revision 1.29
> diff -u -p -r1.29 acinclude.m4
> --- acinclude.m4	22 Dec 2008 19:45:40 -0000	1.29
> +++ acinclude.m4	20 Oct 2009 10:05:02 -0000
> @@ -20,6 +20,17 @@ AC_ARG_ENABLE(multilib,
>     *)   AC_MSG_ERROR(bad value ${enableval} for multilib option) ;;
>    esac], [multilib=yes])dnl
>
> +dnl Support --disable-target-optimization
> +AC_ARG_ENABLE(target-optimization,
> +[  --disable-target-optimization disable automatic optimization support],
> +[if test "${target_optimization+set}" != set; then
> +  case "${enableval}" in
> +    yes) target_optimization=yes ;;
> +    no)  target_optimization=no ;;
> +    *)   AC_MSG_ERROR(bad value ${enableval} for target-optimization option) ;;
> +  esac
> + fi], [target_optimization=${target_optimization}])dnl
> +
>   dnl Support --enable-target-optspace
>   AC_ARG_ENABLE(target-optspace,
>   [  --enable-target-optspace  optimize for space],
> Index: configure.host
> ===================================================================
> RCS file: /cvs/src/src/newlib/configure.host,v
> retrieving revision 1.110
> diff -u -p -r1.110 configure.host
> --- configure.host	8 Oct 2009 16:44:09 -0000	1.110
> +++ configure.host	20 Oct 2009 10:05:02 -0000
> @@ -72,17 +72,20 @@ aext=a
>   oext=o
>   lpfx="lib_a-"
>
> -case "${target_optspace}:${host}" in
> -  yes:*)
> -    newlib_cflags="${newlib_cflags} -Os"
> -    ;;
> -  :m32r-* | :d10v-* | :d30v-* | :avr-* | :m32c-* )
> -    newlib_cflags="${newlib_cflags} -Os"
> -    ;;
> -  no:* | :*)
> -    newlib_cflags="${newlib_cflags} -O2"
> -    ;;
> -esac
> +if [ "${target_optimization}" != "no" ]
> +then
> +  case "${target_optspace}:${host}" in
> +    yes:*)
> +      newlib_cflags="${newlib_cflags} -Os"
> +      ;;
> +    :m32r-* | :d10v-* | :d30v-* | :avr-* | :m32c-* )
> +      newlib_cflags="${newlib_cflags} -Os"
> +      ;;
> +    no:* | :*)
> +      newlib_cflags="${newlib_cflags} -O2"
> +      ;;
> +  esac
> +fi
>
>   # Get the source directories to use for the CPU type.
>   # machine_dir should supply CPU dependent routines, such as setjmp.

Index: configure.host
===================================================================
RCS file: /cvs/src/src/newlib/configure.host,v
retrieving revision 1.110
diff -u -p -r1.110 configure.host
--- configure.host	8 Oct 2009 16:44:09 -0000	1.110
+++ configure.host	20 Oct 2009 16:44:40 -0000
@@ -80,7 +80,6 @@ case "${target_optspace}:${host}" in
     newlib_cflags="${newlib_cflags} -Os"
     ;;
   no:* | :*)
-    newlib_cflags="${newlib_cflags} -O2"
     ;;
 esac