Re: [PATCH] gcc: Add new configure options to allow static libraries to be selected

[Tobias Burnus <tobias at codesourcery dot com>]

Hi Andrew,

I think when committing this patch, you missed to regenerate gcc/configure.

At least with --enable-maintainer-mode, I see the attached changes – and 
I think they come from your patch. (Line numbers might be off as I 
edited out my changes.) — The other changes are due to 
https://gcc.gnu.org/ml/gcc-patches/2020-01/msg01920.html

Can you check? – I haven't checked whether any other sub-configures have 
to be regenerated, maybe some other lib*/configure need to be updated as 
well.

Cheers,

Tobias

On 1/27/20 11:03 PM, Andrew Burgess wrote:
> * Jeff Law <law@redhat.com> [2020-01-22 13:52:27 -0700]:
>
> > On Wed, 2020-01-22 at 15:39 +0000, Andrew Burgess wrote:
> > > The motivation behind this change is to make it easier for a user to
> > > link against static libraries on a target where dynamic libraries are
> > > the default library type (for example GNU/Linux).
> > >
> > > Further, my motivation is really for linking libraries into GDB,
> > > however, the binutils-gdb/config/ directory is a copy of gcc/config/
> > > so changes for GDB need to be approved by the GCC project first.
> > >
> > > After making this change in the gcc/config/ directory I've run
> > > autoreconf on all of the configure scripts in the GCC tree and a
> > > couple have been updated, so I'll use one of these to describe what my
> > > change does.
> > >
> > > Consider libcpp, this library links against lib
> > >
> > > Can you check? – I haven't checked whether any other sub-configures 
> > > have to be regenerated, maybe some other lib*/configure need  to be 
> > > updated as well.
> > >
> > > iconv.  Currently if
> > > the user builds on a system with both static and dynamic libiconv
> > > installed then autotools will pick up the dynamic libiconv by
> > > default.  This is almost certainly the right thing to do.
> > >
> > > However, if the user wants to link against static libiconv then things
> > > are a little harder, they could remove the dynamic libiconv from their
> > > system, but this is probably a bad idea (other things might depend on
> > > that library), or the user can build their own version of libiconv,
> > > install it into a unique prefix, and then configure gcc using the
> > > --with-libiconv-prefix=DIR flag.  This works fine, but is somewhat
> > > annoying, the static library available, I just can't get autotools to
> > > use it.
> > >
> > > My change then adds a new flag --with-libiconv-type=TYPE, where type
> > > is either auto, static, or shared.  The default auto, ensures we keep
> > > the existing behaviour unchanged.
> > >
> > > If the user configures with --with-libiconv-type=static then the
> > > configure script will ignore any dynamic libiconv it finds, and will
> > > only look for a static libiconv, if no static libiconv is found then
> > > the configure will continue as though there is no libiconv at all
> > > available.
> > >
> > > Similarly a user can specify --with-libiconv-type=shared and force the
> > > use of shared libiconv, any static libiconv will be ignored.
> > >
> > > As I've implemented this change within the AC_LIB_LINKFLAGS_BODY macro
> > > then only libraries configured using the AC_LIB_LINKFLAGS or
> > > AC_LIB_HAVE_LINKFLAGS macros will gain the new configure flag.
> > >
> > > If this is accepted into GCC then there will be follow on patches for
> > > binutils and GDB to regenerate some configure scripts in those
> > > projects.
> > >
> > > For GCC only two configure scripts needed updated after this commit,
> > > libcpp and libstdc++-v3, both of which link against libiconv.
> > >
> > > config/ChangeLog:
> > >
> > > 	* lib-link.m4 (AC_LIB_LINKFLAGS_BODY): Add new
> > > 	--with-libXXX-type=... option.  Use this to guide the selection of
> > > 	either a shared library or a static library.
> > >
> > > libcpp/ChangeLog:
> > >
> > > 	* configure: Regnerate.
> > >
> > > libstdc++-v3/ChangeLog:
> > >
> > > 	* configure: Regnerate.
> > s/Regnerate/Regenerate/
> >
> > This isn't strictly a regression bugfix.  But given the nature of these
> > files I think we probably need to be a bit more lax and allow safe
> > changes so that downstream uses can move forward independent of the gcc
> > development and release schedule.
> >
> > So, OK.
> Thanks for the flexibility.  Now pushed.
>
> Thanks,
> Andrew
diff --git a/gcc/config.in b/gcc/config.in
index ec5c46abdb5..05dc9499f22 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -2185,6 +2191,12 @@
 #endif
 
 
+/* Define if your target C Library properly handles PT_GNU_STACK */
+#ifndef USED_FOR_TARGET
+#undef TARGET_LIBC_GNUSTACK
+#endif
+
+
 /* Define if your target C Library provides the AT_HWCAP value in the TCB */
 #ifndef USED_FOR_TARGET
 #undef TARGET_LIBC_PROVIDES_HWCAP_IN_TCB
diff --git a/gcc/configure b/gcc/configure
index 490fe6ac8e8..facbbacd06a 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -974,6 +974,7 @@ with_zstd_include
 with_zstd_lib
 enable_rpath
 with_libiconv_prefix
+with_libiconv_type
 enable_sjlj_exceptions
 with_gcc_major_version_only
 enable_secureplt
@@ -1811,6 +1812,7 @@ Optional Packages:
   --with-gnu-ld           assume the C compiler uses GNU ld default=no
   --with-libiconv-prefix[=DIR]  search for libiconv in DIR/include and DIR/lib
   --without-libiconv-prefix     don't search for libiconv in includedir and libdir
+  --with-libiconv-type=TYPE     type of library to search for (auto/static/shared)
   --with-gcc-major-version-only
                           use only GCC major number in filesystem paths
   --with-pic              try to use only PIC/non-PIC objects [default=use
@@ -10730,6 +10732,16 @@ if test "${with_libiconv_prefix+set}" = set; then :
 
 fi
 
+
+# Check whether --with-libiconv-type was given.
+if test "${with_libiconv_type+set}" = set; then :
+  withval=$with_libiconv_type;  with_libiconv_type=$withval
+else
+   with_libiconv_type=auto
+fi
+
+  lib_type=`eval echo \$with_libiconv_type`
+
       LIBICONV=
   LTLIBICONV=
   INCICONV=
@@ -10767,13 +10779,13 @@ fi
           found_so=
           found_a=
           if test $use_additional = yes; then
-            if test -n "$shlibext" && test -f "$additional_libdir/lib$name.$shlibext"; then
+            if test -n "$shlibext" && test -f "$additional_libdir/lib$name.$shlibext" && test x$lib_type != xstatic; then
               found_dir="$additional_libdir"
               found_so="$additional_libdir/lib$name.$shlibext"
               if test -f "$additional_libdir/lib$name.la"; then
                 found_la="$additional_libdir/lib$name.la"
               fi
-            else
+            elif test x$lib_type != xshared; then
               if test -f "$additional_libdir/lib$name.$libext"; then
                 found_dir="$additional_libdir"
                 found_a="$additional_libdir/lib$name.$libext"
@@ -10797,13 +10809,13 @@ fi
               case "$x" in
                 -L*)
                   dir=`echo "X$x" | sed -e 's/^X-L//'`
-                  if test -n "$shlibext" && test -f "$dir/lib$name.$shlibext"; then
+                  if test -n "$shlibext" && test -f "$dir/lib$name.$shlibext" && test x$lib_type != xstatic; then
                     found_dir="$dir"
                     found_so="$dir/lib$name.$shlibext"
                     if test -f "$dir/lib$name.la"; then
                       found_la="$dir/lib$name.la"
                     fi
-                  else
+                  elif test x$lib_type != xshared; then
                     if test -f "$dir/lib$name.$libext"; then
                       found_dir="$dir"
                       found_a="$dir/lib$name.$libext"
@@ -11031,8 +11043,13 @@ fi
               done
             fi
           else
-                                                            LIBICONV="${LIBICONV}${LIBICONV:+ }-l$name"
-            LTLIBICONV="${LTLIBICONV}${LTLIBICONV:+ }-l$name"
+                                                            if x$lib_type = xauto || x$lib_type = xshared; then
+              LIBICONV="${LIBICONV}${LIBICONV:+ }-l$name"
+              LTLIBICONV="${LTLIBICONV}${LTLIBICONV:+ }-l$name"
+            else
+              LIBICONV="${LIBICONV}${LIBICONV:+ }-l:lib$name.$libext"
+              LTLIBICONV="${LTLIBICONV}${LTLIBICONV:+ }-l:lib$name.$libext"
+            fi
           fi
         fi
       fi
@@ -18957,7 +18974,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 18960 "configure"
+#line 18977 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19063,7 +19080,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19066 "configure"
+#line 19083 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -29800,6 +29850,23 @@ $as_echo "#define TARGET_LIBC_PROVIDES_HWCAP_IN_TCB 1" >>confdefs.h
 
 fi
 
+# Check if the target LIBC handles PT_GNU_STACK.
+gcc_cv_libc_gnustack=unknown
+case "$target" in
+  mips*-*-linux*)
+
+if test $glibc_version_major -gt 2 \
+  || ( test $glibc_version_major -eq 2 && test $glibc_version_minor -ge 31 ); then :
+  gcc_cv_libc_gnustack=yes
+fi
+    ;;
+esac
+if test x$gcc_cv_libc_gnustack = xyes; then
+
+$as_echo "#define TARGET_LIBC_GNUSTACK 1" >>confdefs.h
+
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking dl_iterate_phdr in target C library" >&5
 $as_echo_n "checking dl_iterate_phdr in target C library... " >&6; }
 gcc_cv_target_dl_iterate_phdr=unknown