fortran: Add -static-libquadmath support [PR46539]

The following patch is a revival of the
https://gcc.gnu.org/legacy-ml/gcc-patches/2014-10/msg00771.html
patch.  While trunk configured against recent glibc and with linker
--as-needed support doesn't really need to link against -lquadmath
anymore, there are still other targets where libquadmath is still in
use.
As has been discussed, making -static-libgfortran imply statically
linking both libgfortran and libquadmath is undesirable because of
the significant licensing differences between the 2 libraries.
Compared to the 2014 patch, this one doesn't handle -lquadmath
addition in the driver, which to me looks incorrect, libgfortran
configure determines where in libgfortran.spec -lquadmath should
be present if at all and with what it should be wrapped, but
analyzes gfortran -### -static-libgfortran stderr and based on
that figures out what gcc/configure.ac determined.

2022-08-17  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
	    Jakub Jelinek  <jakub@redhat.com>

	PR fortran/46539
gcc/
	* common.opt (static-libquadmath): New option.
	* gcc.cc (driver_handle_option): Always accept -static-libquadmath.
	* config/darwin.h (LINK_SPEC): Handle -static-libquadmath.
gcc/fortran/
	* lang.opt (static-libquadmath): New option.
	* invoke.texi (-static-libquadmath): Document it.
	* options.cc (gfc_handle_option): Error out if -static-libquadmath
	is passed but we do not support it.
libgfortran/
	* acinclude.m4 (LIBQUADSPEC): From $FC -static-libgfortran -###
	output determine -Bstatic/-Bdynamic, -bstatic/-bdynamic,
	-aarchive_shared/-adefault linker support or Darwin remapping
	of -lgfortran to libgfortran.a%s and use that around or instead
	of -lquadmath in LIBQUADSPEC.
	* configure: Regenerated.

Co-Authored-By: Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>

2 files changed, 47 insertions, 6 deletions

diff --git a/libgfortran/acinclude.m4 b/libgfortran/acinclude.m4
index b4cc0bd..a73207e 100644
--- a/libgfortran/acinclude.m4
+++ b/libgfortran/acinclude.m4
@@ -356,18 +356,39 @@ AC_DEFUN([LIBGFOR_CHECK_FLOAT128], [
       ac_[]_AC_LANG_ABBREV[]_werror_flag=$ac_xsave_[]_AC_LANG_ABBREV[]_werror_flag
     ])
 
+    dnl Determine -Bstatic ... -Bdynamic etc. support from gfortran -### stderr.
+    touch conftest1.$ac_objext conftest2.$ac_objext
+    LQUADMATH=-lquadmath
+    $FC -static-libgfortran -### -o conftest \
+	conftest1.$ac_objext -lgfortran conftest2.$ac_objext 2>&1 >/dev/null \
+	| grep "conftest1.$ac_objext.*conftest2.$ac_objext" > conftest.cmd
+    if grep "conftest1.$ac_objext.* -Bstatic -lgfortran -Bdynamic .*conftest2.$ac_objext" \
+       conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:-Bstatic} -lquadmath %{static-libquadmath:-Bdynamic}"
+    elif grep "conftest1.$ac_objext.* -bstatic -lgfortran -bdynamic .*conftest2.$ac_objext" \
+         conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:-bstatic} -lquadmath %{static-libquadmath:-bdynamic}"
+    elif grep "conftest1.$ac_objext.* -aarchive_shared -lgfortran -adefault .*conftest2.$ac_objext" \
+         conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:-aarchive_shared} -lquadmath %{static-libquadmath:-adefault}"
+    elif grep "conftest1.$ac_objext.*libgfortran.a .*conftest2.$ac_objext" \
+         conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:libquadmath.a%s;:-lquadmath}"
+    fi
+    rm -f conftest1.$ac_objext conftest2.$ac_objext conftest conftest.cmd
+
     dnl For static libgfortran linkage, depend on libquadmath only if needed.
     dnl If using *f128 APIs from libc/libm, depend on libquadmath only if needed
     dnl even for dynamic libgfortran linkage, and don't link libgfortran against
     dnl -lquadmath.
     if test "x$libgfor_cv_have_as_needed" = xyes; then
       if test "x$USE_IEC_60559" = xyes; then
-	LIBQUADSPEC="$libgfor_cv_as_needed_option -lquadmath $libgfor_cv_no_as_needed_option"
+	LIBQUADSPEC="$libgfor_cv_as_needed_option $LQUADMATH $libgfor_cv_no_as_needed_option"
       else
-	LIBQUADSPEC="%{static-libgfortran:$libgfor_cv_as_needed_option} -lquadmath %{static-libgfortran:$libgfor_cv_no_as_needed_option}"
+	LIBQUADSPEC="%{static-libgfortran:$libgfor_cv_as_needed_option} $LQUADMATH %{static-libgfortran:$libgfor_cv_no_as_needed_option}"
       fi
     else
-      LIBQUADSPEC="-lquadmath"
+      LIBQUADSPEC="$LQUADMATH"
     fi
     if test "x$USE_IEC_60559" != xyes; then
       if test -f ../libquadmath/libquadmath.la; then
diff --git a/libgfortran/configure b/libgfortran/configure
index 581f1dc..beb0ec4 100755
--- a/libgfortran/configure
+++ b/libgfortran/configure
@@ -30323,14 +30323,34 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libgfor_cv_have_as_needed" >&5
 $as_echo "$libgfor_cv_have_as_needed" >&6; }
 
+        touch conftest1.$ac_objext conftest2.$ac_objext
+    LQUADMATH=-lquadmath
+    $FC -static-libgfortran -### -o conftest \
+	conftest1.$ac_objext -lgfortran conftest2.$ac_objext 2>&1 >/dev/null \
+	| grep "conftest1.$ac_objext.*conftest2.$ac_objext" > conftest.cmd
+    if grep "conftest1.$ac_objext.* -Bstatic -lgfortran -Bdynamic .*conftest2.$ac_objext" \
+       conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:-Bstatic} -lquadmath %{static-libquadmath:-Bdynamic}"
+    elif grep "conftest1.$ac_objext.* -bstatic -lgfortran -bdynamic .*conftest2.$ac_objext" \
+         conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:-bstatic} -lquadmath %{static-libquadmath:-bdynamic}"
+    elif grep "conftest1.$ac_objext.* -aarchive_shared -lgfortran -adefault .*conftest2.$ac_objext" \
+         conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:-aarchive_shared} -lquadmath %{static-libquadmath:-adefault}"
+    elif grep "conftest1.$ac_objext.*libgfortran.a .*conftest2.$ac_objext" \
+         conftest.cmd >/dev/null 2>&1; then
+      LQUADMATH="%{static-libquadmath:libquadmath.a%s;:-lquadmath}"
+    fi
+    rm -f conftest1.$ac_objext conftest2.$ac_objext conftest conftest.cmd
+
                     if test "x$libgfor_cv_have_as_needed" = xyes; then
       if test "x$USE_IEC_60559" = xyes; then
-	LIBQUADSPEC="$libgfor_cv_as_needed_option -lquadmath $libgfor_cv_no_as_needed_option"
+	LIBQUADSPEC="$libgfor_cv_as_needed_option $LQUADMATH $libgfor_cv_no_as_needed_option"
       else
-	LIBQUADSPEC="%{static-libgfortran:$libgfor_cv_as_needed_option} -lquadmath %{static-libgfortran:$libgfor_cv_no_as_needed_option}"
+	LIBQUADSPEC="%{static-libgfortran:$libgfor_cv_as_needed_option} $LQUADMATH %{static-libgfortran:$libgfor_cv_no_as_needed_option}"
       fi
     else
-      LIBQUADSPEC="-lquadmath"
+      LIBQUADSPEC="$LQUADMATH"
     fi
     if test "x$USE_IEC_60559" != xyes; then
       if test -f ../libquadmath/libquadmath.la; then