c++: clean up the handling of empty symbols

[bison.git] / configure.ac

diff --git a/configure.ac b/configure.ac
index 328d9294b7af1ff539466ccb1ee8b1ef934c9db4..559b50547d6f6e6a658c21e19884b8f23b5ea073 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,6 @@
 # Configure template for GNU Bison.                   -*-Autoconf-*-
 #
 # Configure template for GNU Bison.                   -*-Autoconf-*-
 #

-# Copyright (C) 2001-2012 Free Software Foundation, Inc.
+# Copyright (C) 2001-2015 Free Software Foundation, Inc.

 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by


@@ -18,7 +18,7 @@
 # In order for some versions of Sun Studio to compile our C++ test cases
 # correctly, we need Autoconf 2.64 or better to handle the restrict
 # keyword in at least string.h from gnulib.  We need Autoconf 2.68 or
 # In order for some versions of Sun Studio to compile our C++ test cases
 # correctly, we need Autoconf 2.64 or better to handle the restrict
 # keyword in at least string.h from gnulib.  We need Autoconf 2.68 or

-# better to avoid a typo in the `configure --help' entry for the YACC
+# better to avoid a typo in the 'configure --help' entry for the YACC

 # environment variable.
 AC_PREREQ([2.68])
 m4_pattern_forbid([^gl_[A-Z]])
 # environment variable.
 AC_PREREQ([2.68])
 m4_pattern_forbid([^gl_[A-Z]])


@@ -26,18 +26,14 @@ m4_pattern_forbid([^gl_[A-Z]])
 AC_INIT([GNU Bison],
         m4_esyscmd([build-aux/git-version-gen .tarball-version]),
         [bug-bison@gnu.org])
 AC_INIT([GNU Bison],
         m4_esyscmd([build-aux/git-version-gen .tarball-version]),
         [bug-bison@gnu.org])

-AC_SUBST([PACKAGE_COPYRIGHT_YEAR], [2012])
+AC_SUBST([PACKAGE_COPYRIGHT_YEAR], [2015])

 AC_DEFINE_UNQUOTED([PACKAGE_COPYRIGHT_YEAR], [$PACKAGE_COPYRIGHT_YEAR],
                    [The copyright year for this package])
 
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])
 
 AC_DEFINE_UNQUOTED([PACKAGE_COPYRIGHT_YEAR], [$PACKAGE_COPYRIGHT_YEAR],
                    [The copyright year for this package])
 
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])
 

-# Automake 1.10.3 and 1.11.1 fix a security flaw discussed here:
-#
-#   http://thread.gmane.org/gmane.comp.sysutils.autotools.announce/131
-#
-# To avoid 1.11, we make 1.11.1 the minimum version.
+# We use Automake 1.14's %D% and %C%.

 #
 # We want gnits strictness only when rolling a stable release.  For
 # release candidates, we use version strings like 2.4.3_rc1, but gnits
 #
 # We want gnits strictness only when rolling a stable release.  For
 # release candidates, we use version strings like 2.4.3_rc1, but gnits


@@ -45,7 +41,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # releases, we want to be able run make dist without being required to
 # add a bogus NEWS entry.  In that case, the version string
 # automatically contains a dash, which we also let disable gnits.
 # releases, we want to be able run make dist without being required to
 # add a bogus NEWS entry.  In that case, the version string
 # automatically contains a dash, which we also let disable gnits.

-AM_INIT_AUTOMAKE([1.11.1 dist-xz nostdinc
+AM_INIT_AUTOMAKE([1.14 dist-xz nostdinc

                  color-tests parallel-tests
                  silent-rules]
                  m4_bmatch(m4_defn([AC_PACKAGE_VERSION]), [[-_]],
                  color-tests parallel-tests
                  silent-rules]
                  m4_bmatch(m4_defn([AC_PACKAGE_VERSION]), [[-_]],


@@ -60,32 +56,79 @@ AC_PROG_CXX
 # Gnulib (early checks).
 gl_EARLY
 
 # Gnulib (early checks).
 gl_EARLY
 

+# Gnulib uses '#pragma GCC diagnostic push' to silence some
+# warnings, but older gcc doesn't support this.
+AC_CACHE_CHECK([whether pragma GCC diagnostic push works],
+  [lv_cv_gcc_pragma_push_works], [
+  save_CFLAGS=$CFLAGS
+  CFLAGS='-Wunknown-pragmas -Werror'
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic pop
+  ]])],
+  [lv_cv_gcc_pragma_push_works=yes],
+  [lv_cv_gcc_pragma_push_works=no])
+  CFLAGS=$save_CFLAGS])
+

 AC_ARG_ENABLE([gcc-warnings],
 AC_ARG_ENABLE([gcc-warnings],

-[  --enable-gcc-warnings   turn on lots of GCC warnings (not recommended)],
+[  --enable-gcc-warnings   turn on lots of GCC warnings (not recommended).
+                           Also, issue synclines from the examples/ to
+                           the corresponding source in the Texinfo doc.],

 [case $enable_gcc_warnings in
    yes|no) ;;
    *)  AC_MSG_ERROR([invalid value for --gcc-warnings: $enable_gcc_warnings]);;
  esac],
               [enable_gcc_warnings=no])
 [case $enable_gcc_warnings in
    yes|no) ;;
    *)  AC_MSG_ERROR([invalid value for --gcc-warnings: $enable_gcc_warnings]);;
  esac],
               [enable_gcc_warnings=no])

+AM_CONDITIONAL([ENABLE_GCC_WARNINGS], [test "$enable_gcc_warnings" = yes])

 if test "$enable_gcc_warnings" = yes; then
 if test "$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_common='-Wall-Wextra -Wno-sign-compare -Wcast-align -Wdocumentation
+    -Wformat -Wpointer-arith -Wwrite-strings'
+  warn_c='-Wbad-function-cast -Wshadow -Wstrict-prototypes'

   warn_cxx='-Wnoexcept'
   warn_cxx='-Wnoexcept'

+  # Warnings for the test suite only.
+  #
+  # -fno-color-diagnostics: Clang's use of colors in the error
+  # messages is confusing the tests looking at the compiler's output
+  # (e.g., synclines.at).
+  warn_tests='-Wundef -pedantic -Wsign-compare -fno-color-diagnostics'

 
   AC_LANG_PUSH([C])
 
   AC_LANG_PUSH([C])

+  # Clang supports many of GCC's -W options, but only issues warnings
+  # on the ones it does not recognize.  In that case, gl_WARN_ADD
+  # thinks the option is supported, and unknown options are then added
+  # to CFLAGS.  But then, when -Werror is added in the test suite for
+  # instance, the warning about the unknown option turns into an
+  # error.
+  #
+  # This should be addressed by gnulib's gl_WARN_ADD, but in the
+  # meanwhile, turn warnings about unknown options into errors in
+  # CFLAGS, and restore CFLAGS after the tests.
+  save_CFLAGS=$CFLAGS
+  gl_WARN_ADD([-Werror=unknown-warning-option], [CFLAGS])

   for i in $warn_common $warn_c;
   do
     gl_WARN_ADD([$i], [WARN_CFLAGS])
   done
   gl_WARN_ADD([-Werror], [WERROR_CFLAGS])
   for i in $warn_common $warn_c;
   do
     gl_WARN_ADD([$i], [WARN_CFLAGS])
   done
   gl_WARN_ADD([-Werror], [WERROR_CFLAGS])

+
+  # Warnings for the test suite, and maybe for bison if GCC is modern
+  # enough.
+  gl_WARN_ADD([-Wmissing-declarations], [WARN_CFLAGS_TEST])
+  gl_WARN_ADD([-Wmissing-prototypes], [WARN_CFLAGS_TEST])
+  test $lv_cv_gcc_pragma_push_works = yes &&
+    AS_VAR_APPEND([WARN_CFLAGS], [" $WARN_CFLAGS_TEST"])
+

   # Warnings for the test suite only.
   # Warnings for the test suite only.

-  gl_WARN_ADD([-Wundef], [WARN_CFLAGS_TEST])
-  gl_WARN_ADD([-pedantic], [WARN_CFLAGS_TEST])
+  for i in $warn_tests;
+  do
+    gl_WARN_ADD([$i], [WARN_CFLAGS_TEST])
+  done
+  CFLAGS=$save_CFLAGS

   AC_LANG_POP([C])
 
   AC_LANG_PUSH([C++])
   AC_LANG_POP([C])
 
   AC_LANG_PUSH([C++])

+  save_CXXFLAGS=$CXXFLAGS
+  gl_WARN_ADD([-Werror=unknown-warning-option], [CXXFLAGS])

   for i in $warn_common $warn_cxx;
   do
     gl_WARN_ADD([$i], [WARN_CXXFLAGS])
   for i in $warn_common $warn_cxx;
   do
     gl_WARN_ADD([$i], [WARN_CXXFLAGS])


@@ -94,32 +137,40 @@ if test "$enable_gcc_warnings" = yes; then
               [AC_LANG_PROGRAM([], [nullptr])])
   gl_WARN_ADD([-Werror], [WERROR_CXXFLAGS])
   # Warnings for the test suite only.
               [AC_LANG_PROGRAM([], [nullptr])])
   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])
+  for i in $warn_tests;
+  do
+    gl_WARN_ADD([$i], [WARN_CXXFLAGS_TEST])
+  done
+  # Clang++ 3.2+ reject C code generated by Flex.
+  gl_WARN_ADD([-Wno-null-conversion], [FLEX_SCANNER_CXXFLAGS])
+  # So does G++ 4.8...
+  gl_WARN_ADD([-Wno-sign-compare], [FLEX_SCANNER_CXXFLAGS])
+  # ... possiby in std=c++11 mode.
+  gl_WARN_ADD([-Wno-zero-as-null-pointer-constant], [FLEX_SCANNER_CXXFLAGS])
+  CXXFLAGS=$save_CXXFLAGS

   AC_LANG_POP([C++])
 fi
 
 BISON_TEST_FOR_WORKING_C_COMPILER
   AC_LANG_POP([C++])
 fi
 
 BISON_TEST_FOR_WORKING_C_COMPILER

+BISON_C_COMPILER_POSIXLY_CORRECT

 BISON_TEST_FOR_WORKING_CXX_COMPILER
 BISON_TEST_FOR_WORKING_CXX_COMPILER

+BISON_CXX_COMPILER_POSIXLY_CORRECT

 
 AC_ARG_ENABLE([yacc],
   [AC_HELP_STRING([--disable-yacc],
      [do not build a yacc command or an -ly library])],
   , [enable_yacc=yes])
 
 AC_ARG_ENABLE([yacc],
   [AC_HELP_STRING([--disable-yacc],
      [do not build a yacc command or an -ly library])],
   , [enable_yacc=yes])

-case $enable_yacc in
-yes)
-  YACC_SCRIPT=src/yacc
-  YACC_LIBRARY=lib/liby.a;;
-*)
-  YACC_SCRIPT=
-  YACC_LIBRARY=;;
-esac
-AC_SUBST([YACC_SCRIPT])
-AC_SUBST([YACC_LIBRARY])
+AM_CONDITIONAL([ENABLE_YACC], [test "$enable_yacc" = yes])

 
 # Checks for programs.
 
 # Checks for programs.

+AM_MISSING_PROG([DOT], [dot])

 AC_PROG_LEX
 AC_PROG_LEX

-$LEX_IS_FLEX || AC_MSG_ERROR([Flex is required])
+$LEX_IS_FLEX || test "X$LEX" = X: || {
+  AC_MSG_WARN([bypassing lex because flex is required])
+  LEX=:
+}
+AM_CONDITIONAL([FLEX_CXX_WORKS],
+  [$LEX_IS_FLEX && test $bison_cv_cxx_works = yes])

 AC_PROG_YACC
 AC_PROG_RANLIB
 AC_PROG_GNU_M4
 AC_PROG_YACC
 AC_PROG_RANLIB
 AC_PROG_GNU_M4


@@ -174,12 +225,21 @@ case $VALGRIND:$host_os in
   '':*) ;;
   *:darwin*)
     # See README-hacking.
   '':*) ;;
   *:darwin*)
     # See README-hacking.

-    # VALGRIND+=' --suppressions=$(abs_top_srcdir)/build-aux/darwin11.4.0.valgrind'
+    # VALGRIND+='-q --suppressions=$(abs_top_srcdir)/build-aux/darwin11.4.0.valgrind'

     VALGRIND=;;
   *:*)
     VALGRIND=;;
   *:*)

-    AC_SUBST([VALGRIND_PREBISON], ["$VALGRIND -q"]);;
+    suppfile=build-aux/$host_os.valgrind
+    if test -f "$srcdir/$suppfile"; then
+      VALGRIND="$VALGRIND --gen-suppressions=all"
+      VALGRIND="$VALGRIND --suppressions=\$(abs_top_srcdir)/$suppfile"
+    fi
+    AC_SUBST([VALGRIND_PREBISON], ["$VALGRIND -q"])
+    ;;

 esac
 
 esac
 

+# Whether we cannot run the compiled bison.
+AM_CONDITIONAL([CROSS_COMPILING], [test "$cross_compiling" = yes])
+

 AM_MISSING_PROG([AUTOM4TE], [autom4te])
 # Needed by tests/atlocal.in.
 AC_SUBST([GCC])
 AM_MISSING_PROG([AUTOM4TE], [autom4te])
 # Needed by tests/atlocal.in.
 AC_SUBST([GCC])


@@ -187,19 +247,6 @@ AC_SUBST([GCC])
 gt_JAVACOMP([1.3], [1.4])
 gt_JAVAEXEC
 
 gt_JAVACOMP([1.3], [1.4])
 gt_JAVAEXEC
 

-# We use gnulib, but from lib/local.mk instead of lib/Makefile.am.
-# So prefix paths with lib/.  See also etc/prefix-gnulib-mk.
-gl_LIBOBJS=`echo "$gl_LIBOBJS" | sed -e 's, , lib/,g'`
-# Listing the names of the variables to prefix is error-prone.
-# Rather, adjust all the AC_SUBST variables whose name ends in '_H',
-# and whose content ends in '.h'.
-for ac_var in $ac_subst_vars
-do
-  eval "ac_val=\$$ac_var"
-  case $ac_var=$ac_val in
-    (*_H=*.h) eval "$ac_var=lib/\$$ac_var";;
-  esac
-done

 AC_CONFIG_FILES([Makefile
                  po/Makefile.in
                  doc/yacc.1])
 AC_CONFIG_FILES([Makefile
                  po/Makefile.in
                  doc/yacc.1])