[PATCH] configure: Don't check LD -v --help for LIBC_LINKER_FEATURE

Fāng-ruì Sòng maskray@google.com
Wed Oct 20 18:04:25 GMT 2021


On Tue, Oct 19, 2021 at 10:02 AM Fāng-ruì Sòng <maskray@google.com> wrote:
>
> On Mon, Oct 11, 2021 at 5:25 PM Fangrui Song <maskray@google.com> wrote:
> >
> > When LIBC_LINKER_FEATURE is used to check a linker option with the equal
> > sign, it will likely fail because the LD -v --help output may look like
> > `-z lam-report=[none|warning|error]` while the needle is something like
> > `-z lam-report=warning`.
> >
> > The LD -v --help filter doesn't save much time, so just remove it.
> > ---
> >  aclocal.m4                                | 19 +++---
> >  configure                                 | 76 ++++++++++-------------
> >  sysdeps/unix/sysv/linux/powerpc/configure | 19 +++---
> >  3 files changed, 48 insertions(+), 66 deletions(-)
> >
> > diff --git a/aclocal.m4 b/aclocal.m4
> > index c195c4db56..65a12df047 100644
> > --- a/aclocal.m4
> > +++ b/aclocal.m4
> > @@ -224,20 +224,17 @@ AC_DEFUN([LIBC_LINKER_FEATURE],
> >  [AC_MSG_CHECKING([for linker that supports $1])
> >  libc_linker_feature=no
> >  if test x"$gnu_ld" = x"yes"; then
> > -  libc_linker_check=`$LD -v --help 2>/dev/null | grep "\$1"`
> > -  if test -n "$libc_linker_check"; then
> > -    cat > conftest.c <<EOF
> > +  cat > conftest.c <<EOF
> >  int _start (void) { return 42; }
> >  EOF
> > -    if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > -                               $2 -nostdlib -nostartfiles
> > -                               -fPIC -shared -o conftest.so conftest.c
> > -                               1>&AS_MESSAGE_LOG_FD])
> > -    then
> > -      libc_linker_feature=yes
> > -    fi
> > -    rm -f conftest*
> > +  if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > +                   $2 -nostdlib -nostartfiles
> > +                   -fPIC -shared -o conftest.so conftest.c
> > +                   1>&AS_MESSAGE_LOG_FD])
> > +  then
> > +    libc_linker_feature=yes
> >    fi
> > +  rm -f conftest*
> >  fi
> >  if test $libc_linker_feature = yes; then
> >    $3
> > diff --git a/configure b/configure
> > index 39d75eb4ed..3227e434d3 100755
> > --- a/configure
> > +++ b/configure
> > @@ -5979,25 +5979,22 @@ fi
> >  $as_echo_n "checking for linker that supports -z execstack... " >&6; }
> >  libc_linker_feature=no
> >  if test x"$gnu_ld" = x"yes"; then
> > -  libc_linker_check=`$LD -v --help 2>/dev/null | grep "\-z execstack"`
> > -  if test -n "$libc_linker_check"; then
> > -    cat > conftest.c <<EOF
> > +  cat > conftest.c <<EOF
> >  int _start (void) { return 42; }
> >  EOF
> > -    if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > -                               -Wl,-z,execstack -nostdlib -nostartfiles
> > -                               -fPIC -shared -o conftest.so conftest.c
> > -                               1>&5'
> > +  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > +                   -Wl,-z,execstack -nostdlib -nostartfiles
> > +                   -fPIC -shared -o conftest.so conftest.c
> > +                   1>&5'
> >    { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> >    (eval $ac_try) 2>&5
> >    ac_status=$?
> >    $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> >    test $ac_status = 0; }; }
> > -    then
> > -      libc_linker_feature=yes
> > -    fi
> > -    rm -f conftest*
> > +  then
> > +    libc_linker_feature=yes
> >    fi
> > +  rm -f conftest*
> >  fi
> >  if test $libc_linker_feature = yes; then
> >    libc_cv_z_execstack=yes
> > @@ -6012,25 +6009,22 @@ $as_echo "$libc_linker_feature" >&6; }
> >  $as_echo_n "checking for linker that supports -z start-stop-gc... " >&6; }
> >  libc_linker_feature=no
> >  if test x"$gnu_ld" = x"yes"; then
> > -  libc_linker_check=`$LD -v --help 2>/dev/null | grep "\-z start-stop-gc"`
> > -  if test -n "$libc_linker_check"; then
> > -    cat > conftest.c <<EOF
> > +  cat > conftest.c <<EOF
> >  int _start (void) { return 42; }
> >  EOF
> > -    if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > -                               -Wl,-z,start-stop-gc -nostdlib -nostartfiles
> > -                               -fPIC -shared -o conftest.so conftest.c
> > -                               1>&5'
> > +  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > +                   -Wl,-z,start-stop-gc -nostdlib -nostartfiles
> > +                   -fPIC -shared -o conftest.so conftest.c
> > +                   1>&5'
> >    { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> >    (eval $ac_try) 2>&5
> >    ac_status=$?
> >    $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> >    test $ac_status = 0; }; }
> > -    then
> > -      libc_linker_feature=yes
> > -    fi
> > -    rm -f conftest*
> > +  then
> > +    libc_linker_feature=yes
> >    fi
> > +  rm -f conftest*
> >  fi
> >  if test $libc_linker_feature = yes; then
> >    libc_cv_z_start_stop_gc=yes
> > @@ -6046,25 +6040,22 @@ have-z-start-stop-gc = $libc_cv_z_start_stop_gc"
> >  $as_echo_n "checking for linker that supports --depaudit... " >&6; }
> >  libc_linker_feature=no
> >  if test x"$gnu_ld" = x"yes"; then
> > -  libc_linker_check=`$LD -v --help 2>/dev/null | grep "\--depaudit"`
> > -  if test -n "$libc_linker_check"; then
> > -    cat > conftest.c <<EOF
> > +  cat > conftest.c <<EOF
> >  int _start (void) { return 42; }
> >  EOF
> > -    if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > -                               -Wl,--depaudit,x -nostdlib -nostartfiles
> > -                               -fPIC -shared -o conftest.so conftest.c
> > -                               1>&5'
> > +  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > +                   -Wl,--depaudit,x -nostdlib -nostartfiles
> > +                   -fPIC -shared -o conftest.so conftest.c
> > +                   1>&5'
> >    { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> >    (eval $ac_try) 2>&5
> >    ac_status=$?
> >    $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> >    test $ac_status = 0; }; }
> > -    then
> > -      libc_linker_feature=yes
> > -    fi
> > -    rm -f conftest*
> > +  then
> > +    libc_linker_feature=yes
> >    fi
> > +  rm -f conftest*
> >  fi
> >  if test $libc_linker_feature = yes; then
> >    libc_cv_depaudit=yes
> > @@ -6080,25 +6071,22 @@ have-depaudit = $libc_cv_depaudit"
> >  $as_echo_n "checking for linker that supports --no-dynamic-linker... " >&6; }
> >  libc_linker_feature=no
> >  if test x"$gnu_ld" = x"yes"; then
> > -  libc_linker_check=`$LD -v --help 2>/dev/null | grep "\--no-dynamic-linker"`
> > -  if test -n "$libc_linker_check"; then
> > -    cat > conftest.c <<EOF
> > +  cat > conftest.c <<EOF
> >  int _start (void) { return 42; }
> >  EOF
> > -    if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > -                               -Wl,--no-dynamic-linker -nostdlib -nostartfiles
> > -                               -fPIC -shared -o conftest.so conftest.c
> > -                               1>&5'
> > +  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > +                   -Wl,--no-dynamic-linker -nostdlib -nostartfiles
> > +                   -fPIC -shared -o conftest.so conftest.c
> > +                   1>&5'
> >    { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> >    (eval $ac_try) 2>&5
> >    ac_status=$?
> >    $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> >    test $ac_status = 0; }; }
> > -    then
> > -      libc_linker_feature=yes
> > -    fi
> > -    rm -f conftest*
> > +  then
> > +    libc_linker_feature=yes
> >    fi
> > +  rm -f conftest*
> >  fi
> >  if test $libc_linker_feature = yes; then
> >    libc_cv_no_dynamic_linker=yes
> > diff --git a/sysdeps/unix/sysv/linux/powerpc/configure b/sysdeps/unix/sysv/linux/powerpc/configure
> > index ceb1bd7c1b..a4c809fd98 100644
> > --- a/sysdeps/unix/sysv/linux/powerpc/configure
> > +++ b/sysdeps/unix/sysv/linux/powerpc/configure
> > @@ -80,25 +80,22 @@ fi
> >  $as_echo_n "checking for linker that supports --no-tls-get-addr-optimize... " >&6; }
> >  libc_linker_feature=no
> >  if test x"$gnu_ld" = x"yes"; then
> > -  libc_linker_check=`$LD -v --help 2>/dev/null | grep "\--no-tls-get-addr-optimize"`
> > -  if test -n "$libc_linker_check"; then
> > -    cat > conftest.c <<EOF
> > +  cat > conftest.c <<EOF
> >  int _start (void) { return 42; }
> >  EOF
> > -    if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > -                               -Wl,--no-tls-get-addr-optimize -nostdlib -nostartfiles
> > -                               -fPIC -shared -o conftest.so conftest.c
> > -                               1>&5'
> > +  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
> > +                   -Wl,--no-tls-get-addr-optimize -nostdlib -nostartfiles
> > +                   -fPIC -shared -o conftest.so conftest.c
> > +                   1>&5'
> >    { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> >    (eval $ac_try) 2>&5
> >    ac_status=$?
> >    $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> >    test $ac_status = 0; }; }
> > -    then
> > -      libc_linker_feature=yes
> > -    fi
> > -    rm -f conftest*
> > +  then
> > +    libc_linker_feature=yes
> >    fi
> > +  rm -f conftest*
> >  fi
> >  if test $libc_linker_feature = yes; then
> >    libc_cv_tls_get_addr_optimize=yes
> > --
> > 2.33.0.882.g93a45727a2-goog
> >
>
> Ping🥳

This cleans up code and prevents a pitfall. I'll push it if there has
been no objection.


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