[PATCH v2] Fortran Cray pointer macro support

[Marshall Ward]

This patch adds the AC_F77_CRAY_POINTERS and AC_FC_CRAY_POINTERS macros,
which test if the Fortran compiler supports Cray pointers.

The macros are written such that the tests share a common backend
(_AC_FC_CRAY_POINTERS) which works on both F77 and FC compilers.
Wrappers are provided to address any future potential compatibility
issues.

The macros include additional tests for particular flags required by
GFortran and PGI compilers.  The current set of flags is sparse, but can
be extended for other compilers if needed.

Documentation and a minimal test of the macro have been included.

Two minor variable name typos (@EXEEXT@ as @EEXEXT@) were also fixed in
two of the other Fortran tests.
---
This renames the macros from *_CRAY_POINTER to *_CRAY_POINTERS and
introduces an additional macro for F77 support.

Test cases and documentation are also included.

 doc/autoconf.texi       | 22 ++++++++++
 lib/autoconf/fortran.m4 | 72 +++++++++++++++++++++++++++++++++
 tests/fortran.at        | 89 ++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 181 insertions(+), 2 deletions(-)

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index dea85e4a..42fa4e60 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -8565,6 +8565,28 @@ The substituted value of @code{FC_MODOUT} may refer to 
the
 the significant trailing whitespace in a @file{Makefile}.
 @end defmac
 
+@defmac AC_F77_CRAY_POINTERS (@ovar{action-if-success}, @
+  @dvar{action-if-failure, AC_MSG_FAILURE})
+@defmac AC_FC_CRAY_POINTERS (@ovar{action-if-success}, @
+  @dvar{action-if-failure, AC_MSG_FAILURE})
+@acindex{F77_CRAY_POINTERS}
+@acindex{FC_CRAY_POINTERS}
+@caindex fc_cray_pointer
+
+Try to ensure that the Fortran compiler (@code{$F77} or @code{$FC})
+accepts Cray pointers.  If successful, the @var{action-if-success} is
+called and any needed flags are added to @code{FFLAGS} or
+@code{FCFLAGS}.  Otherwise, @var{action-if-failure} is called, which
+defaults to failing with an error message.
+
+Cray pointers are a non-standard extension supported by many Fortran
+compilers which allow an integer to be declared as C-like pointer to
+a target variable.
+
+The result of this test, or @samp{none} or @samp{unknown}, is cached in
+the @code{ac_cv_f77_cray_ptr} or @code{ac_cv_fc_cray_ptr} variable.
+@end defmac
+
 
 @node Go Compiler
 @subsection Go Compiler Characteristics
diff --git a/lib/autoconf/fortran.m4 b/lib/autoconf/fortran.m4
index 59a8859b..44e1ab9f 100644
--- a/lib/autoconf/fortran.m4
+++ b/lib/autoconf/fortran.m4
@@ -1857,3 +1857,75 @@ AC_CONFIG_COMMANDS_PRE([case $FC_MODOUT in #(
   *\ ) FC_MODOUT=$FC_MODOUT'${ac_empty}' ;;
 esac])dnl
 ])
+
+
+# _AC_FC_CRAY_POINTERS([ACTION-IF-SUCCESS], [ACTION-IF-FAILURE = FAILURE])
+#-------------------------------------------------------------------------
+# Try to ensure that the Fortran compiler supports Cray pointers, a
+# non-standard extension that provides a C-like pointer in Fortran.
+#
+# If successful, ACTION-IF-SUCCESS is called.  If no argument is provided, then
+# any necessary flags are added to F[C]FLAGS.  Otherwise, ACTION-IF-FAILURE is
+# called, which defaults to failing with an error message.
+#
+# Most compilers provide an implementation of Cray pointers, and often no
+# additional flags are required to enable support.  A partial list of compilers
+# and flags which may be required are listed below.
+#
+# The known flags are:
+#   -fcray-pointer: gfortran
+#   -Mcray-pointer: PGI
+AC_DEFUN([_AC_FC_CRAY_POINTERS], [
+  dnl AC_LANG_PUSH([Fortran])
+  AC_MSG_CHECKING([for $[]_AC_FC[] option to support Cray pointers])
+  AC_CACHE_VAL([ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr], [
+    ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr='unknown'
+    ac_save_[]_AC_LANG_PREFIX[]FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
+    for ac_option in none -fcray-pointer -Mcray=pointer; do
+      test "$ac_option" != none && 
_AC_LANG_PREFIX[]FLAGS="$ac_save_[]_AC_LANG_PREFIX[]FLAGS $ac_option"
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([], [
+      integer aptr(2)
+      pointer (iptr, aptr)
+        ])],
+        [ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr=$ac_option],
+      )
+      _AC_LANG_PREFIX[]FLAGS=$ac_save_[]_AC_LANG_PREFIX[]FLAGS
+      AS_IF([test "$ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr" != unknown], [break])
+    done
+  ])
+  AS_CASE([ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr],
+    [none], [AC_MSG_RESULT([none_needed])],
+    [unknown], [AC_MSG_RESULT([unsupported])],
+    [AC_MSG_RESULT([$ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr])]
+  )
+  AS_IF([test "$ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr" != unknown], [
+    m4_default([$1], [
+      AS_IF([test "$ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr" != none],
+        [_AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS 
$ac_cv_[]_AC_LANG_ABBREV[]_cray_ptr"]
+      )
+    ])],
+    [m4_default([$2], [AC_MSG_ERROR(["$[]_AC_FC[] does not support Cray 
pointers"])])]
+  )
+  dnl AC_LANG_POP([Fortran])
+])
+
+
+# AC_F77_CRAY_POINTERS
+#---------------------
+AC_DEFUN([AC_F77_CRAY_POINTERS], [
+  AC_REQUIRE([AC_PROG_F77])
+  AC_LANG_PUSH([Fortran 77])
+  _AC_FC_CRAY_POINTERS($@)
+  AC_LANG_POP([Fortran 77])
+])
+
+
+# AC_FC_CRAY_POINTERS
+#--------------------
+AC_DEFUN([AC_FC_CRAY_POINTERS], [
+  AC_REQUIRE([AC_PROG_FC])
+  AC_LANG_PUSH([Fortran])
+  _AC_FC_CRAY_POINTERS($@)
+  AC_LANG_POP([Fortran])
+])
diff --git a/tests/fortran.at b/tests/fortran.at
index cf4d9fef..f7804f6d 100644
--- a/tests/fortran.at
+++ b/tests/fortran.at
@@ -997,7 +997,7 @@ AT_DATA([Makefile.in],
        @FC@ @FCFLAGS@ -c @FCFLAGS_f@ $<
 
 clean:
-       rm -f *.@OBJEXT@ prog@EEXEXT@
+       rm -f *.@OBJEXT@ prog@EXEEXT@
 ]])
 
 # When preceded by 7 spaces and followed by newline, line_80 generates
@@ -1069,7 +1069,7 @@ AT_DATA([Makefile.in],
        @FC@ @FCFLAGS@ -c @FCFLAGS_f@ $<
 
 clean:
-       rm -f *.@OBJEXT@ prog@EEXEXT@
+       rm -f *.@OBJEXT@ prog@EXEEXT@
 ]])
 
 cat >configure.ac <<EOF
@@ -1180,3 +1180,88 @@ AT_CHECK([./prog], [], [ignore], [ignore])
 AT_CHECK_MAKE([clean])
 
 AT_CLEANUP
+
+
+## --------------------- ##
+## AC_F77_CRAY_POINTERS. ##
+## --------------------- ##
+
+AT_SETUP([AC_F77_CRAY_POINTERS])
+
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_PROG_F77
+AC_F77_CRAY_POINTERS
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
+]])
+
+AT_DATA([Makefile.in],
+[[prog@EXEEXT@: prog.@OBJEXT@
+       @F77@ @FFLAGS@ -o $@ prog.@OBJEXT@ @LIBS@
+
+.SUFFIXES: .f .@OBJEXT@
+.f.@OBJEXT@:
+       @F77@ @FFLAGS@ -c $<
+
+clean:
+       rm -f *.@OBJEXT@ prog@EXEEXT@
+]])
+
+AT_DATA([prog.f],
+[[      program main
+      integer aptr(2)
+      pointer (iptr, aptr)
+      end
+]])
+
+AT_CHECK_AUTOCONF
+AT_CHECK_CONFIGURE
+AT_CHECK_MAKE
+AT_CHECK([./prog])
+AT_CHECK_MAKE([clean])
+
+AT_CLEANUP
+
+
+## -------------------- ##
+## AC_FC_CRAY_POINTERS. ##
+## -------------------- ##
+
+AT_SETUP([AC_FC_CRAY_POINTERS])
+
+AT_DATA([configure.ac],
+[[AC_INIT
+AC_PROG_FC
+AC_FC_SRCEXT([f])
+AC_FC_CRAY_POINTERS
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
+]])
+
+AT_DATA([Makefile.in],
+[[prog@EXEEXT@: prog.@OBJEXT@
+       @FC@ @FCFLAGS@ -o $@ prog.@OBJEXT@ @LIBS@
+
+.SUFFIXES: .f .@OBJEXT@
+.f.@OBJEXT@:
+       @FC@ @FCFLAGS@ -c @FCFLAGS_f@ $<
+
+clean:
+       rm -f *.@OBJEXT@ prog@EXEEXT@
+]])
+
+AT_DATA([prog.f],
+[[      program main
+      integer aptr(2)
+      pointer (iptr, aptr)
+      end
+]])
+
+AT_CHECK_AUTOCONF
+AT_CHECK_CONFIGURE
+AT_CHECK_MAKE
+AT_CHECK([./prog])
+AT_CHECK_MAKE([clean])
+
+AT_CLEANUP
-- 
2.28.0