Daniel Jacobowitz - Re: Toplevel PR 30753 (original) (raw)

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Re: Toplevel PR 30753 - Fix non-native builds

• From: Daniel Jacobowitz
• To: gcc-patches at gcc dot gnu dot org
• Date: Tue, 13 Feb 2007 08:39:32 -0500
• Subject: Re: Toplevel PR 30753 - Fix non-native builds
• References: <20070212155950.GA4044@caradoc.them.org> <45D0AA03.5050500@lu.unisi.ch> <20070212180240.GA10875@caradoc.them.org> <45D15B25.3060804@lu.unisi.ch>

On Tue, Feb 13, 2007 at 07:31:01AM +0100, Paolo Bonzini wrote:

Yes, but please leave the CFLAGS=${CFLAGS-"-g"} because I know that some people prefer to have it.

What's it for and where does it belong? It can't possibly have anything to do with the build={build} = build={host} test, I don't think.

It's because the toplevel's default for CFLAGS is -g, which is later overridden to "-g -O2" when bootstrapping. If I had to quote by memory, I would have said indeed that it belonged more to host = target than to build = host.

If you really want to scrap it, go for it -- but be prepared that someone complains.

I stopped to think about this remark and got very worried. If it had really worked the way you describe, then the default whenever building a cross compiler would have been CFLAGS=-g. I think we'd have noticed that - since the slowdown for a non-optimized GCC is huge, on the order of 40%.

The line didn't actually do anything, because AC_PROG_CC always sets CFLAGS to something, and this only set a default if no value was set. Just as well, since it ignored the result of the autoconf test for whether $CC supported -g.

Now, if I move it before AC_PROG_CC, then it works. But a bunch of my configurations suddenly start building un-optimized by default when they didn't previously (i.e. with autoconf 2.13). So, I'm not going to do that :-)

The other remark, that the LD test must go after AC_PROG_CC, of course still holds.

Right, thank you for noticing. Here's what I'm checking in.

-- Daniel Jacobowitz CodeSourcery

2007-02-13 Daniel Jacobowitz dan@codesourcery.com Paolo Bonzini bonzini@gnu.org

PR bootstrap/30753
* configure.ac: Remove obsolete build / host tests.  Use AC_PROG_CC
unconditionally.  Use AC_PROG_CXX.  Use ACX_TOOL_DIRS to find $prefix.
* configure: Regenerated.

Index: configure.ac

--- configure.ac (revision 121846) +++ configure.ac (working copy) @@ -1030,49 +1030,31 @@ if test -z "${CC}" && test "${build}" = fi if test "${build}" != "${host}" ; then - # If we are doing a Canadian Cross, in which the host and build systems - # are not the same, we set reasonable default values for the tools.

• CC=${CC-${host_noncanonical}-gcc}

• CFLAGS=${CFLAGS-"-g -O2"}

• CXX=${CXX-${host_noncanonical}-c++}

• CXXFLAGS=${CXXFLAGS-"-g -O2"} CC_FOR_BUILD=${CC_FOR_BUILD-gcc}

• else

• Set reasonable default values for some tools even if not Canadian.

• Of course, these are different reasonable default values, originally

• specified directly in the Makefile.

• We don't export, so that autoconf can do its job.

• Note that all these settings are above the fragment inclusion point

• in Makefile.in, so can still be overridden by fragments.

• This is all going to change when we autoconfiscate...

• CC_FOR_BUILD="$(CC)"

• AC_PROG_CC +fi

• We must set the default linker to the linker used by gcc for the correct

• operation of libtool. If LD is not defined and we are using gcc, try to

• set the LD default to the ld used by gcc.

• if test -z "$LD"; then

• if test "$GCC" = yes; then

•  case $build in

•  *-*-mingw*)

• gcc_prog_ld=$CC -print-prog-name=ld 2>&1 | tr -d '\015' ;;

•  *)

• gcc_prog_ld=$CC -print-prog-name=ld 2>&1 ;;

•  esac

•  case $gcc_prog_ld in

•  # Accept absolute paths.

•  [[\\/]* | [A-Za-z]:[\\/]*)]

•    LD="$gcc_prog_ld" ;;

•  esac

• fi

• fi +AC_PROG_CC +AC_PROG_CXX

• CXX=${CXX-"c++"}

• CFLAGS=${CFLAGS-"-g"}

• CXXFLAGS=${CXXFLAGS-"-g -O2"} +# We must set the default linker to the linker used by gcc for the correct +# operation of libtool. If LD is not defined and we are using gcc, try to +# set the LD default to the ld used by gcc. +if test -z "$LD"; then

• if test "$GCC" = yes; then
• case $build in
• --mingw*)

•  gcc_prog_ld=`$CC -print-prog-name=ld 2>&1 | tr -d '\015'` ;;

• *)

•  gcc_prog_ld=`$CC -print-prog-name=ld 2>&1` ;;

• esac
• case $gcc_prog_ld in

• Accept absolute paths.

• [[\/]* | [A-Za-z]:[\/]*)]

•  LD="$gcc_prog_ld" ;;

• esac
• fi fi

ACX_PROG_GNAT @@ -1578,6 +1560,9 @@ case "$host" in enable_gdbtk=no ;; esac

+# To find our prefix, in gcc_cv_tool_prefix. +ACX_TOOL_DIRS + copy_dirs=

AC_ARG_WITH([build-sysroot], @@ -1597,10 +1582,7 @@ if test x"${with_headers}" != x && test exit 1 fi if test x"${with_headers}" != xyes ; then

• case "${exec_prefixoption}" in
• "") x=${prefix} ;;
• *) x=${exec_prefix} ;;
• esac

• x=${gcc_cv_tool_prefix} copy_dirs="${copy_dirs} withheaders{with_headers} withh​eadersx/${target_noncanonical}/sys-include" fi fi @@ -1616,10 +1598,7 @@ if test x"${with_libs}" != x && test x"$ if test x"${with_libs}" != xyes ; then

  Copy the libraries in reverse order, so that files in the first named

  library override files in subsequent libraries.

• case "${exec_prefixoption}" in
• "") x=${prefix} ;;
• *) x=${exec_prefix} ;;
• esac

• x=${gcc_cv_tool_prefix} for l in ${with_libs}; do copy_dirs="$l x/x/x/{target_noncanonical}/lib ${copy_dirs}" done

• References:
  • Toplevel PR 30753 - Fix non-native builds
    * From: Daniel Jacobowitz
  • Re: Toplevel PR 30753 - Fix non-native builds
    * From: Paolo Bonzini
  • Re: Toplevel PR 30753 - Fix non-native builds
    * From: Daniel Jacobowitz
  • Re: Toplevel PR 30753 - Fix non-native builds
    * From: Paolo Bonzini