maint: build: simplify and improve the compiler warnings for tests

[Akim Demaille]

The code for warnings was quite complex, for no
good reason.  BTW, at some point I had broken
the removal of -O2 in my tests, and as a result
I had many new warnings that do now show in -O0.

-O0 was introduced here:

commit f377f69fec28013c79db4efe12bbb9d48987fb2c
Author: Akim Demaille <address@hidden>
Date:   Sun Oct 13 18:49:44 2002 +0000

    * configure.ac (AC_GNU_SOURCE): Use it instead of hand written code.
    (O0FLAGS): New.
    (VALGRIND, GXX): New.
    * tests/atlocal.in (CFLAGS): Use O0FLAGS.
    * tests/bison.in: Run $PREBISON a pre-command.
    * tests/Makefile.am (maintainer-check, maintainer-check-valgrind)
    (maintainer-check-g++): New.
    * Makefile.am (maintainer-check): New.

and I don't see enough justification here to understand
why we should not use the regular flags.  So I plan to
remove this -O2 removal.

There are opportunities to factor bw C and C++ here
in configure.ac, but I first wait to see how things
evolve in gnulib on this regard.

For maint now, master when merged.

(Patch 2 simply upgraded gnulib)

From e85056ef5fe3ddf7563a217b941c27de7d7b3cb5 Mon Sep 17 00:00:00 2001
From: Akim Demaille <address@hidden>
Date: Tue, 27 Mar 2012 16:20:34 +0200
Subject: [PATCH 3/4] build: simplify and improve the compiler warnings for
 tests.

* configure.ac (warn_common, warn_c, warn_cxx): New.
Use them to compute independently the options supported
by the C and C++ compilers.
Don't AC_SUBST the variables passed to gl_WARN_ADD: it
does it for us.
(WARN_CFLAGS_TEST, WARN_CXXFLAGS_TEST): Don't aggregate
$WARN_CFLAGS and $WARN_CXXFLAGS in them now, leave it
to atlocal.in.
(O0CFLAGS, O0CXXFLAGS): Move their definition to...
* tests/atlocal.in: here.
Be more systematic between C and C++.
Reorder to factor between variables.
Propagate all of the variables when --compile-c-with-cxx.
---
 configure.ac     |   46 ++++++++++++++++++++++++----------------------
 tests/atlocal.in |   50 ++++++++++++++++++++++++++++++--------------------
 2 files changed, 54 insertions(+), 42 deletions(-)

diff --git a/configure.ac b/configure.ac
index 1fffa67..78f641d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,6 +53,7 @@ AC_CONFIG_HEADERS([lib/config.h:lib/config.hin])
 
 # Checks for the compiler.
 AC_PROG_CC_STDC
+AC_PROG_CXX
 
 # Gnulib (early checks).
 gl_EARLY
@@ -65,31 +66,36 @@ AC_ARG_ENABLE([gcc-warnings],
  esac],
               [enable_gcc_warnings=no])
 if test "$enable_gcc_warnings" = yes; then
+  warn_common='-Wall -Wextra -Wno-sign-compare -Wcast-align
+    -Wcast-qual -Wformat -Wpointer-arith -Wwrite-strings'
+  warn_c='-Wbad-function-cast -Wmissing-declarations -Wmissing-prototypes
+    -Wshadow -Wstrict-prototypes'
+  warn_cxx=''
+  AC_LANG_PUSH([C])
+  for i in $warn_common $warn_c;
+  do
+    gl_WARN_ADD([$i], [WARN_CFLAGS])
+  done
   gl_WARN_ADD([-Werror], [WERROR_CFLAGS])
-  AC_SUBST([WERROR_CFLAGS])
-  gl_WARN_ADD([-Wall])
-  gl_WARN_ADD([-Wextra -Wno-sign-compare])
-  gl_WARN_ADD([-Wcast-align])
-  gl_WARN_ADD([-Wcast-qual])
-  gl_WARN_ADD([-Wformat])
-  gl_WARN_ADD([-Wpointer-arith])
-  gl_WARN_ADD([-Wwrite-strings])
-  AC_SUBST([WARN_CXXFLAGS], [$WARN_CFLAGS])
-  # The following warnings are not suitable for C++.
-  gl_WARN_ADD([-Wbad-function-cast])
-  gl_WARN_ADD([-Wmissing-declarations])
-  gl_WARN_ADD([-Wmissing-prototypes])
-  gl_WARN_ADD([-Wshadow])
-  gl_WARN_ADD([-Wstrict-prototypes])
-  AC_SUBST([WARN_CFLAGS])
   # Warnings for the test suite only.
   gl_WARN_ADD([-Wundef], [WARN_CFLAGS_TEST])
   gl_WARN_ADD([-pedantic], [WARN_CFLAGS_TEST])
-  AC_SUBST([WARN_CXXFLAGS_TEST], ["$WARN_CXXFLAGS $WARN_CFLAGS_TEST"])
-  AC_SUBST([WARN_CFLAGS_TEST], ["$WARN_CFLAGS $WARN_CFLAGS_TEST"])
+  AC_LANG_POP([C])
+
+  AC_LANG_PUSH([C++])
+  for i in $warn_common $warn_cxx;
+  do
+    gl_WARN_ADD([$i], [WARN_CXXFLAGS])
+  done
+  gl_WARN_ADD([-Werror], [WERROR_CXXFLAGS])
+  # Warnings for the test suite only.
+  gl_WARN_ADD([-Wundef], [WARN_CXXFLAGS_TEST])
+  gl_WARN_ADD([-pedantic], [WARN_CXXFLAGS_TEST])
+  AC_LANG_POP([C++])
 fi
 
 BISON_TEST_FOR_WORKING_C_COMPILER
+BISON_TEST_FOR_WORKING_CXX_COMPILER
 
 AC_ARG_ENABLE([yacc],
   [AC_HELP_STRING([--disable-yacc],
@@ -155,13 +161,9 @@ AC_CONFIG_TESTDIR(tests)
 AC_CONFIG_FILES([tests/Makefile tests/atlocal])
 AC_CONFIG_FILES([tests/bison], [chmod +x tests/bison])
 AC_CHECK_PROGS([VALGRIND], [valgrind])
-AC_PROG_CXX
-BISON_TEST_FOR_WORKING_CXX_COMPILER
 AM_MISSING_PROG([AUTOM4TE], [autom4te])
 # Needed by tests/atlocal.in.
 AC_SUBST([GCC])
-AC_SUBST([O0CFLAGS],   [`echo $CFLAGS   | sed 's/-O[[0-9]] *//'`])
-AC_SUBST([O0CXXFLAGS], [`echo $CXXFLAGS | sed 's/-O[[0-9]] *//'`])
 
 gt_JAVACOMP([1.3])
 gt_JAVAEXEC
diff --git a/tests/atlocal.in b/tests/atlocal.in
index 11554b3..72a9bf7 100644
--- a/tests/atlocal.in
+++ b/tests/atlocal.in
@@ -16,30 +16,47 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# We need a C compiler.
+# We need `config.h'.
+CPPFLAGS="-I$abs_top_builddir/lib @CPPFLAGS@"
+
+## ------------------- ##
+## C/C++ Compilation.  ##
+## ------------------- ##
+
 : ${CC='@CC@'}
+: ${CXX='@CXX@'}
+
+# Is the compiler GCC?
+GCC='@GCC@'
 
 # We want no optimization.
-CFLAGS='@O0CFLAGS@ @WARN_CFLAGS_TEST@ @WERROR_CFLAGS@'
+  O0CFLAGS=`echo '@CFLAGS@'   | sed 's/-O[0-9] *//'`
+O0CXXFLAGS=`echo '@CXXFLAGS@' | sed 's/-O[0-9] *//'`
 
 # Sometimes a test group needs to ignore gcc warnings, so it locally
 # sets CFLAGS to this.
-NO_WERROR_CFLAGS='@O0CFLAGS@ @WARN_CFLAGS_TEST@'
+  NO_WERROR_CFLAGS="$O0CFLAGS   @WARN_CFLAGS@   @WARN_CFLAGS_TEST@"
+NO_WERROR_CXXFLAGS="$O0CXXFLAGS @WARN_CXXFLAGS@ @WARN_CXXFLAGS_TEST@"
 
-# We need `config.h'.
-CPPFLAGS="-I$abs_top_builddir/lib @CPPFLAGS@"
-
-# Is the compiler GCC?
-GCC='@GCC@'
-
-# The C++ compiler.
-: ${CXX='@CXX@'}
+# But most of the time, we want -Werror.
+  CFLAGS="$NO_WERROR_CFLAGS   @WERROR_CFLAGS@"
+CXXFLAGS="$NO_WERROR_CXXFLAGS @WERROR_CXXFLAGS@"
 
 # If 'exit 77'; skip all C++ tests; otherwise ':'.
 BISON_CXX_WORKS='@BISON_CXX_WORKS@'
 
-# We want no optimization with C++, too.
-CXXFLAGS='@O0CXXFLAGS@ @WARN_CXXFLAGS_TEST@ @WERROR_CFLAGS@'
+# Handle --compile-c-with-cxx here, once CXX and CXXFLAGS are known.
+if "$at_arg_compile_c_with_cxx"; then
+  CC=$CXX
+  O0CFLAGS=$O0CXXFLAGS
+  NO_WERROR_CFLAGS=$NO_WERROR_CXXFLAGS
+  CFLAGS=$CXXFLAGS
+fi
+
+
+## ------- ##
+## Other.  ##
+## ------- ##
 
 # Are special link options needed?
 LDFLAGS='@LDFLAGS@'
@@ -62,10 +79,3 @@ CONF_JAVA='@CONF_JAVA@'
 # Use simple quotes (lib/quote.c).
 LC_CTYPE=C
 export LC_CTYPE
-
-
-# Handle --compile-c-with-cxx here, once CXX and CXXFLAGS are known.
-if "$at_arg_compile_c_with_cxx"; then
-  CC=$CXX
-  CFLAGS=$CXXFLAGS
-fi
-- 
1.7.9.4