Commit Graph

6799 Commits

Author SHA1 Message Date
Paul Eggert
411d0c0ef5 Modernize discussion of integer overflow
* doc/autoconf.texi (Integer Overflow, Integer Overflow Basics)
(Signed Overflow Examples, Optimization and Wraparound):
Modernize discussion to take current compiler and Gnulib
technology into account.
2021-08-31 16:10:30 -07:00
Paul Eggert
7b3aa70a73 Port test to next m4 version
* tests/tools.at (autom4te cache):
Allow m4 to quote 'like this' as well as 'like this'.
2021-08-31 16:10:30 -07:00
Marshall Ward
6cfdc56489 Fortran Cray pointer macro support
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.
2021-08-16 09:56:09 -07:00
Eric Blake
706847e2d0 tests: typo fix
* tests/base.at: Fix typo.
Spotted by anonymous in https://savannah.gnu.org/support/?110526
2021-08-12 13:05:42 -05:00
Paul Eggert
64df9b4523 Autoconf now quotes 'like this' instead of `like this'
Autoconf’s diagnostics now follow current GNU coding standards,
which say that diagnostics in the C locale should quote 'like this'
with plain apostrophes instead of the older GNU style `like this'
with grave accent and apostrophe.
2021-07-20 16:04:21 -05:00
Paul Eggert
7b1b9e4650 Document unquoted here-documents better
Problem reported by Bruno Haible (sr #110518).
* doc/autoconf.texi (Generating Sources)
(Running the Preprocessor, Running the Compiler)
(Running the Linker, Runtime): Briefly mention that the program
snippets are expanded as unquoted here-documents.
(Here-Documents): Document escaping needed in unquoted
here-documents.  Remove mention of \" glitch in OpenBSD 2.7 sh;
that old system has not been supported for many years.
Remove advice that every \ must be quoted, as that sort
of quoting (though harmless) is not needed and is rarely done.
* lib/autoconf/c.m4 (AC_C_BIGENDIAN, _AC_LANG_OPENMP(Fortran 77)):
* lib/autoconf/types.m4 (AC_TYPE_LONG_LONG_INT): Properly quote
code snippets.  The backslash-newline typos were harmless, and the
backslash-$ typo has unspecified behavior as per POSIX though the
typo is harmless on all shells I know of.  However, Autoconf
should follow its own quoting advice.
2021-07-18 23:55:45 -05:00
Emanuele Giaquinta
f982d9e4e1 doc: fix typo in variable name
Message-Id: <YJ4Tm3WEkv86L/YV@FSAPPLE2215.fi.f-secure.com>
(tiny change)
2021-06-30 14:59:44 -05:00
Emanuele Giaquinta
f460883035 _AC_PROG_CXX_STDCXX_EDITION_TRY: fix typo in variable name
The typo causes "ac_prog_cxx_stdcxx" to be always set to "cxx11",
regardless of whether the C++ compiler supports C++11.
Message-Id: <YJ4TXAeJcvU0oSec@FSAPPLE2215.fi.f-secure.com>
(tiny change)
2021-06-30 14:53:54 -05:00
Eric Blake
a1b9ba4790 maint: advertise GNU in README
* README: Add section to attract more people towards the GNU project.
Inspired by a suggestion from Jose E. Marchesi <jemarch@gnu.org> on
the gnu-prog-discuss mailing list.
2021-05-10 15:50:42 -05:00
Eric Blake
c8b84ee327 maint: ensure autoconf-latest.* links stay up-to-date
* cfg.mk (GNUPLOADFLAGS): New.
https://lists.gnu.org/archive/html/autoconf/2021-05/msg00006.html
2021-05-10 15:45:24 -05:00
Eric Blake
fb37d4cfc7 maint: Add names to THANKS
* THANKS: Add names that resulted in several recent commits. Also
tweak addresses per owner requests.
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-05-10 15:43:31 -05:00
Ben Elliston
c0fb65f673 update HACKING file
Fairly obvious - be gender neutral in who gets thanked.
* HACKING: Tweak pronouns.
Message-Id: <20151125100819.GA29844@air.net.au>
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-05-10 15:21:47 -05:00
Zack Weinberg
6d38e9fa2b
trunk post-release administrivia
Matching the commits on the release branch:

* NEWS: Bring over record of release notes.
* .prev-version: Record previous version.
* cfg.mk (old_NEWS_hash): Auto-update.
2021-01-28 17:54:10 -05:00
Zack Weinberg
378351df7e
make fetch 2021-01-28 15:21:49 -05:00
Zack Weinberg
300349c84b
make update-copyright 2021-01-28 15:19:21 -05:00
Zack Weinberg
66fdaea3cf
autoreconf: don’t error out when AM_GNU_GETTEXT is used alone.
Some projects intentionally don't call AM_GNU_GETTEXT_(REQUIRE_)VERSION
because they have all of the gettext infrastructure checked into version
control and they want autoreconf to _not_ run autopoint.  Therefore, make
the “AM_GNU_GETTEXT is used, but not AM_GNU_GETTEXT_(REQUIRE_)VERSION”
and “AM_GNU_GETTEXT_(REQUIRE_)VERSION is used, but not AM_GNU_GETTEXT”
diagnostics be warnings again, as they were in 2.69.

(Technically these diagnostics were always errors, in the sense that
they were reported with a call to Autom4te::Channels::error(), but
prior to 2.70, error() calls made by autoreconf did not cause
autoreconf to exit unsuccessfully, due to an unrelated bug.  So people
came to depend on these diagnostics not being fatal.)
2021-01-04 17:27:37 -05:00
Bruno Haible
fbcc365d41
doc: Document another portability problem of 'od'.
* doc/autoconf.texi (Limitations of Usual Tools): Document that decimal output
is not portable.
2020-12-30 10:21:48 -05:00
Paul Eggert
925922406c
doc: modernize grep discussion 2020-12-30 10:07:15 -05:00
Zack Weinberg
07130c3e48
autom4te: always update the output file, even if it hasn’t changed
Automake generates a Makefile rule for regenerating the configure
script, that relies on an invocation of ‘autoconf’ always bumping the
timestamp on the configure script, even if it hasn’t changed.
The patch to make autom4te update the output file atomically
(1725c94714) broke this.

Fixes several failures in automake’s test suite.

 * bin/autom4te.in (handle_output): Always call update_file with force=1.
 * tests/tools.at (autoconf: timestamp changes): New test.
2020-12-29 15:33:33 -05:00
Zack Weinberg
2d0f19d84d
Restore compatibility with older std-gnu11.m4.
Gnulib’s std-gnu11.m4 backports C11 and C++11 detection to autoconf
2.69.  It does this by replacing the definitions of AC_PROC_CC and
AC_PROG_CXX and most of their subroutines.  In particular, it replaces
the definitions of _AC_PROG_CC_C11, _AC_PROG_CC_C99, and _AC_C_STD_TRY,
but it does *not* replace the definition of _AC_PROG_CC_C89.

Autoconf commit 131d8c69f3 changed the
calling convention of _AC_C_STD_TRY, and changed the internal
definitions of _AC_PROG_CC_C{11,99,89} to match.  If std-gnu11.m4 is
in use, our _AC_PROG_CC_C89 calls their _AC_C_STD_TRY with the new
calling convention, and this produces a syntactically invalid
configure script.  (This is is fortunate: it could easily have been a
runtime malfunction that only manifested with compilers that only
implement C89, and then we might not have noticed the problem for
years.)

Gnulib commit a3b3fc85e3e632374811b27cb2111e50fa177e36 makes
std-gnu11.m4 do nothing when used with autoconf >=2.70, but older
versions of the file will circulate for years to come, so this patch
works around the problem in autoconf.  It does this by renaming all of
the internal macros involved with C and C++ standard edition
detection, *except* _AC_PROG_CC_C89.  AC_PROG_CC now calls
_AC_PROG_CC_STDC_EDITION, which loops over all supported editions
calling _AC_PROG_CC_STDC_EDITION_TRY, which uses the data provided by
the existing _AC_C_C${edition}_TEST_PROGRAM macros and a new set of
macros called _AC_C_C${edition}_OPTIONS to perform the test for that
edition of the standard.  Similarly, AC_PROG_CXX calls
_AC_PROG_CXX_STDCXX_EDITION, which loops calling
_AC_PROG_CXX_STDCXX_EDITION_TRY, which uses data from
_AC_CXX_CXX${edition}_TEST_PROGRAM and _AC_CXX_CXX${edition}_OPTIONS.

_AC_PROG_CC_C89 is the only macro from the old set that we still
define, and its definition is reverted to what std-gnu11.m4 expects it
to be.  Nothing in Autoconf proper uses it anymore.

foreign.at grows a test to verify that the compatibility stub version
of _AC_PROG_CC_C89 does its job.  Since this is now the third test
involving an embedded copy of a third-party macro, I broke them all
out of foreign.at to separate files in test/data/.

In addition to fixing the breakage, this patch should make it easier
to extend C / C++ standard edition detection in the future, by getting
rid of the if-else chains in AC_PROG_CC/CXX and by disentangling the
lists of command-line options to test from the logic.

I also changed the manual to suggest people refer to the variables
‘ac_prog_cc_stdc’ and ‘ac_prog_cxx_stdcxx’ to learn which edition
of the C and C++ standards are selected; these are much easier to
work with than the ac_cv_prog_cc_cNN cache variables.

* lib/autoconf/c.m4 (_AC_C_STD_TRY, _AC_PROG_CC_C99, _AC_PROG_CC_C11)
  (_AC_CXX_STD_TRY, _AC_PROG_CXX_CXX98, _AC_PROG_CXX_CXX11): Remove macro.

  (_AC_C_C89_OPTIONS, _AC_C_C99_OPTIONS, _AC_C_C11_OPTIONS)
  (_AC_PROG_CC_STDC_EDITION, _AC_PROG_CC_STDC_EDITION_TRY)
  (_AC_CXX_CXX98_OPTIONS, _AC_CXX_CXX11_OPTIONS)
  (_AC_PROG_CXX_STDCXX_EDITION, _AC_PROG_CXX_STDCXX_EDITION_TRY): New macros.

  (_AC_PROG_CC_C89): Convert to compatibility stub for std-gnu11.m4.

  (AC_PROG_CC): Use _AC_PROG_CC_STDC_EDITION.
  (AC_PROG_CXX): Use _AC_PROG_CXX_STDCXX_EDITION.

* tests/data/ax_prog_cc_for_build_v18.m4
* tests/data/ax_prog_cxx_for_build_v3.m4
* tests/data/gnulib_std_gnu11_2020_08_17.m4: New files.
* tests/foreign.at (AX_PROG_CC_FOR_BUILD, AX_PROG_CXX_FOR_BUILD):
  Remove embedded copy of ax_prog_cc_for_build_v18.m4,
  ax_prog_cxx_for_build_v3.m4 respectively.
  (gnulib-std-gnu11.m4): New test.
* tests/local.mk: Distribute tests/data/*.m4.

* doc/autoconf.texi (AC_PROG_CC, AC_PROG_CXX): Document use of
  ac_prog_cc_stdc / ac_prog_cxx_stdcxx, respectively, to tell which
  edition of the C / C++ standards are selected, instead of looking
  through a series of cache variables with awkward definitions.
2020-12-23 13:42:28 -05:00
Zack Weinberg
ec90049dfc
Use -fno-builtin, not -Werror, in AC_CHECK_DECLS (#110400)
clang issues only a warning, not an error, when an undeclared
identifier that names a built-in function is used: for instance

    char *(*p)(const char *, int) = strchr;

(with no `#include <string.h>`) is an error with most compilers,
a warning with clang.  This broke the 2.69 implementation of
AC_CHECK_DECL.  In commit 82ef7805fa,
we tried to work around this quirk by using -Werror, but that put us
at risk of being tripped up by other warnings.  Bug 110400 reports,
for instance, that this fragment (which is roughly what you get, after
preprocessing, when AC_CHECK_DECL is applied to a function that *is*
properly declared)

    extern void ac_decl (int, char *);
    int main (void)
    {
      (void) ac_decl;
      ;
      return 0;
    }

provokes a warning from clang (and thus an error) when -Wextra-semi-stmt
has been added to CFLAGS earlier in the configure script.  The extra
semicolon comes from AC_LANG_PROGRAM, and we can’t get rid of it
because we have no way of telling reliably when someone wrote
something like

    AC_LANG_PROGRAM([[#include <stdio.h>]],
                    [[puts("hello world")]])

with no semicolon at the end of the statement; this has been
acceptable for decades.  Besides, that’s just one warning, who knows
what compilers will start complaining about tomorrow?

So: change AC_CHECK_DECL to compile its programs with -fno-builtin,
instead, when the default compilation mode fails to detect an
undeclared strchr.  The code is restructured so that we can try other
options as well, if we find another compiler with the same quirk but
different command-line syntax.

(All of this logic is very C-family specific, but it appears to me
that AC_CHECK_DECL has never worked with other languages, so we can
continue to live with that for now.)

Fixes bug 110400; partially reverts 82ef7805fa.

 * lib/autoconf/general.m4 (_AC_UNDECLARED_WARNING): Rename to
   _AC_UNDECLARED_BUILTIN.  Instead of looking at diagnostic output,
   loop trying to find a command-line option that makes the compiler
   error out on undeclared builtins.
   (_AC_CHECK_DECL_BODY): Don’t AC_REQUIRE anything here.
   Make shell code language-agnostic, except for the actual test program.
   Add arguments to the shell function for additional compiler options
   to use.
   (AC_CHECK_DECL): AC_REQUIRE _AC_UNDECLARED_BUILTIN here.
   Supply $ac_{AC_LANG_ABBREV}_undeclared_builtin_options to
   ac_fn_check_decl.

 * tests/local.at (AT_CONFIG_CMP): Update list of variables to ignore
   when comparing C and C++ configure runs.
 * tests/semantics.at (AC_CHECK_DECLS): Add memcpy and strchr to
   AC_CHECK_DECLS call for functions that may be known to the compiler.

 * doc/autoconf.texi (AC_CHECK_DECL, AC_CHECK_DECLS): Remove note
   about compiler warnings.
2020-12-23 13:12:57 -05:00
Zack Weinberg
ea9d7d9f1f
autom4te: correct error message when we can’t create autom4te.cache.
While testing something else, I noticed that autom4te may print a
nonsensical error message when it fails to create autom4te.cache,
because it checks again whether the directory already exists before
giving up, and this clobbers errno.

Instead of doing (the perl equivalent of)
    test -d $cache || mkdir $cache || test -d $cache
call mkdir unconditionally.  If it fails with an errno code other than
EEXIST, consider that a hard failure; if it fails with EEXIST, check
whether the thing that exists is in fact a directory.  (A symlink to
a directory qualifies; I wouldn’t be surprised if people are moving
autom4te.cache around with symlinks.)

Either way, if we fail, report strerror(errno) from the original
mkdir failure.  Also, print the current working directory as part
of the error message; this aids debugging when you’re working with a
big hairy nested tree.

* bin/autom4te.in: Don’t check whether autom4te.cache exists before
  attempting to create it.  Only stat autom4te.cache if mkdir fails
  with EEXIST, otherwise fail immediately.  Make sure to report the
  errno code from mkdir, not the subsequent stat (if any).  Report
  the current working directory as part of the error message.

* tests/tools.at: Verify that autom4te reports the actual reason when
  it fails to create autom4te.cache.  Verify that failure to create
  autom4te.cache because that name exists, but isn’t a directory,
  is detected.
2020-12-23 13:12:51 -05:00
Paul Eggert
237519e6e7 Merge branch 'branch-2.70' into master 2020-12-12 16:10:28 -08:00
Paul Eggert
8118c2adc4 Improve AC_USE_SYSTEM_EXTENSIONS port to HP-UX 11.11
* lib/autoconf/specific.m4 (AC_USE_SYSTEM_EXTENSIONS):
Define _HPUX_ALT_XOPEN_SOCKET_API, for HP-UX 11.11.
This patch is adapted from Gnulib.
2020-12-11 15:25:18 -08:00
Paul Eggert
5c2bcf10c0 Port minor AC_HEADER_MAJOR fixes from Gnulib
* lib/autoconf/headers.m4 (AC_HEADER_MAJOR):
Improve m4 quoting.
2020-12-11 15:25:18 -08:00
Paul Eggert
2f3f782cdd Port minor AC_FUNC_ALLOCA fixes from Gnulib
* lib/autoconf/functions.m4 (_AC_LIBOBJ_ALLOCA, AC_FUNC_ALLOCA):
Use ' not ` in generated comments, as per current GNU coding style.
(_AC_LIBOBJ_ALLOCA): Use plain # instead of unnecessary quadrigraph.
This patch is adapted from Gnulib.
2020-12-11 15:25:18 -08:00
Paul Eggert
8f19de6df0 Improve port of AC_C_RESTRICT to Oracle C++
Problem reported by Christian Biesinger in:
https://lists.gnu.org/r/bug-gnulib/2019-12/msg00159.html
* lib/autoconf/c.m4 (AC_C_RESTRICT): Port better to
Oracle Developer Studio C++ 12.5 or later.
This patch is adapted from Gnulib.
2020-12-11 15:25:18 -08:00
Zack Weinberg
efc940dc82
_AC_PROG_CC_C99: fix typo (#110396)
_AC_PROG_CC_C99 was using the wrong test program.

Fixes #110396, reported anonymously.

* lib/autoconf/c.m4 (_AC_PROG_CC_C99): Use the C99 test program, not
  the C89 test program.
2020-12-08 21:48:10 -05:00
Zack Weinberg
b693e20869
maint: add outline for future NEWS (release branch). 2020-12-08 21:47:13 -05:00
Zack Weinberg
05972f49ee
_AC_PROG_CC_C99: fix typo (#110396)
_AC_PROG_CC_C99 was using the wrong test program.

Fixes #110396, reported anonymously.

* lib/autoconf/c.m4 (_AC_PROG_CC_C99): Use the C99 test program, not
  the C89 test program.
2020-12-08 21:35:45 -05:00
Zack Weinberg
697c1a07cd
maint: add outline for future NEWS 2020-12-08 20:53:13 -05:00
Zack Weinberg
29ed3a774d
maint: post-release administrivia
* NEWS: Add header line for next release.
* .prev-version: Record previous version.
* cfg.mk (old_NEWS_hash): Auto-update.
2020-12-08 13:04:16 -05:00
Zack Weinberg
97fbc5c184
Release 2.70. 2020-12-08 11:31:19 -05:00
Zack Weinberg
5144cd0c44
Remove obsolete instructions from HACKING.
configure CC=g++ is no longer supported, so don’t tell maintainers to
test that.
2020-12-08 11:29:05 -05:00
Zack Weinberg
edbc5693ae
testsuite: log version of M4 and Perl
Jannick reported problems on OSX for which the most plausible
explanation is that the system-provided M4 is emitting error messages
with different line numbers than we expect, perhaps because Apple
froze their copy of GNU M4 to the last GPLv2 release.  To test this
hypothesis, add $PERL and $M4 to AT_TESTED in our testsuite.

* tests/atlocal.in: Also set $M4 from configure.
* tests/local.at: Add AT_TESTED([$PERL $M4]).
2020-12-08 11:14:19 -05:00
Zack Weinberg
3f75cfc927
lib/autotest/general.m4: typo fix
The absolute-path case in AT_TESTED had a typo in it, causing bizarre
error messages and preventing programs identified by absolute path
from being logged properly.

* lib/autotest/general.m4 (AT_TESTED): Fix typoed shell syntax in
  handling of programs identified by absolute path.
2020-12-08 11:12:04 -05:00
Zack Weinberg
48a3113c20
Three minor testsuite fixes.
1. To insulate the test suite from a system-provided config.site file,
set the CONFIG_SITE environment variable to a file that is known not
to exist.  Problem reported by Jannick.

2. AC_PROG_CC, AC_PROG_CXX, AC_PROG_CPP, and AC_PROG_CXXCPP may set
cache variables named ‘ac_cv_prog_$tool’ or ‘ac_cv_prog_ac_ct_$tool’,
depending on system conditions; _AT_CONFIG_CMP_PRUNE needs to handle
both possibilities.  Found by testing on FreeBSD 12; I have no idea
why it didn’t show up on _any_ of my other test platforms.

3. The ‘AC_PROG_LEX with yywrap’ test needs to be skipped on systems
that don’t provide libl.a nor libfl.a.  This change needed yet another
hook for AT_CHECK_MACRO.  Found by testing on Alpine Linux.

(Ideally, instead of skipping this test, we would test that this
configure script *errors out* on these systems, but that would involve
much more invasive changes to AT_CHECK_MACRO, which I don’t want to
hold the release for.)

* tests/local.at (AT_PREPARE_TESTS): Set CONFIG_SITE to refer to
  a file that is known not to exist, and export it.
  (_AT_CONFIG_CMP_PRUNE): Prune all variables matching the
  ERE ‘ac_cv_prog_(ac_ct_)?(CC|CXX|CPP|CXXCPP)’.
  (AT_CHECK_MACRO): Add PRETEST-CMDS argument which takes commands to
  execute immediately after AT_SETUP.
* tests/semantics.at (AC_PROG_LEX with yywrap): Using PRETEST-CMDS,
  skip this test on OSes where neither -ll nor -lfl provides a
  definition of yywrap.
2020-12-08 10:36:28 -05:00
Zack Weinberg
c3afa48883
autoreconf --install --force: replace install-sh with no timestamp
Old versions of install-sh did not have a timestamp line.  Therefore,
treat the absence of a timestamp line as indicating a very old file
(that --install --force should replace), not as an error.

Problem reported by Pascal Terjan.

* bin/autoreconf.in (extract_time_stamp): Return 1970-01-01 when
  no timestamp line is found.
* tests/torture.at (Missing auxiliary files (--force)):
  Test replacement of old install-sh with no timestamp line.
2020-12-08 10:34:31 -05:00
Zack Weinberg
9887fa54b6
make fetch 2020-12-07 17:23:37 -05:00
Zack Weinberg
4e310e78cb
Update documentation of AC_USE_SYSTEM_EXTENSIONS.
The list of macros documented as being defined by
AC_USE_SYSTEM_EXTENSIONS had gotten out of sync with the actual list.
Update it thoroughly.

Also, I introduced an error into the commentary when I merged Julien
ÉLIE’s patch to define _NETBSD_SOURCE and _OPENBSD_SOURCE in
AC_USE_SYSTEM_EXTENSIONS.  _OPENBSD_SOURCE does something on NetBSD
and *doesn’t* do anything on OpenBSD.  This is corrected.

Clean up the code in AC_USE_SYSTEM_EXTENSIONS a bit while I’m in
there; we now had a redundant definition of _NETBSD_SOURCE (one
unconditional and one conditional on minix/config.h existing).
Reorganize the macro to make it easier to catch problems like this in
the future.

* lib/autoconf/specific.m4 (AC_USE_SYSTEM_EXTENSIONS): Reorganize;
  remove redundant AC_DEFINE of _NETBSD_SOURCE; add some missing
  AC_BEFOREs; use _AC_CHECK_HEADER_ONCE for header checks;
  revise all commentary.
* doc/autoconf.texi (AC_USE_SYSTEM_EXTENSIONS): Update.
2020-12-07 17:17:40 -05:00
Zack Weinberg
5ab70f1769
Revise documentation of AT_CHECK.
Patch originally by Jannick but then about 10x more words added by me.
2020-12-07 13:24:46 -05:00
Zack Weinberg
6cf0eff684
Revise documentation of AC_PROG_CC and comments on conformance checks.
Makes the documentation of AC_PROG_CC consistent with the
documentation of AC_PROG_CXX.  Also removes a bunch of redundant text
from c.m4 and adds lists of the headers that *can* be used in the
conformance tests, so future hackers don’t have to look them up.

* doc/autoconf.texi (AC_PROG_CC): Make description consistent with
  description of AC_PROG_CXX.
* lib/autoconf/c.m4: Clean up some outdated or repetitive commentary
  and add lists of the freestanding headers above the code that needs
  to avoid using non-freestanding headers.
2020-12-07 11:53:06 -05:00
Zack Weinberg
d132ea0278
Add checks of __STDC__ and __STDC_VERSION__ to C conformance tests.
This makes the C conformance tests more consistent with the C++
conformance tests, and should also speed up cycling through the
possible options to turn on C99/C11.

Tested with gcc, clang, SunPRO C, and AIX xlc.

* lib/autoconf/c.m4 (_AC_C_C89_TEST_GLOBALS): Add preprocessor test
  for __STDC__ being defined (to any value).
  (_AC_C_C99_TEST_GLOBALS, _AC_C_C11_TEST_GLOBALS): Add preprocessor
  test of the value of __STDC_VERSION__.
2020-12-07 11:49:52 -05:00
Zack Weinberg
b4ec547b86
autom4te: don’t crash when warnings have no stacktrace
In testing on Darwin (OSX), sometimes warnings reported from M4 code
reach autom4te with no stack trace at all, causing the perl script to
crash with a “use of uninitialized value” error.  The root cause of
the problem is not clear to me, but the script certainly shouldn’t
crash.

Problem found by Jannick <thirdedition@gmx.net>.

* bin/autom4te.in: When processing warnings, make sure $stacktrace is
  defined.
2020-12-07 11:32:55 -05:00
Jannick
fbd2636f3d
Small bug fixes for the test suite.
* tests/atlocal.in: Also set AWK to value detected by configure.
  Alphabetize list of shell variables set by config.status.
* tests/local.mk: Add a rule to recreate tests/atconfig when
  config.status changes.
2020-12-07 11:28:57 -05:00
Zack Weinberg
131d8c69f3
Don’t use hosted headers when testing for C(++) standard level (#110393)
The tests for the level of the C and C++ standard supported by their
respective compilers should also avoid using any headers that are not
guaranteed to be available in the respective freestanding environment.

Unlike the previous change, the only user-visible consequence of this
one should be that C11/C99/C89/C++11/C++98 *compiler* support is now
correctly detected when the compilation target is a freestanding
environment.

This patch also refactors how we “emit [the text of the C/C++
standard-conformance test programs] only once per [configure script],
into shell variables which can then be referenced repeatedly,” from
c3853873, because editing them just a little made the M4 quotation
break.  Clearly too fragile.

I believe this completes the fix for bug #110393.

* lib/autoconf/c.m4 (_AC_PROG_CC_C89, _AC_PROG_CC_C99, _AC_PROG_CC_C11)
  _AC_C_C99_TEST_HEADER, _AC_C_C99_TEST_BODY): Move all test program
  fragments into new macros that can be AC_REQUIREd individually:
  _AC_C_C89_TEST_GLOBALS, _AC_C_C89_TEST_MAIN, _AC_C_C89_TEST_PROGRAM,
  _AC_C_C99_TEST_GLOBALS, _AC_C_C99_TEST_MAIN, _AC_C_C99_TEST_PROGRAM,
  _AC_C_C11_TEST_GLOBALS, _AC_C_C11_TEST_MAIN, _AC_C_C11_TEST_PROGRAM.
  Each emits test code at most once, into a shell variable in the
  INIT_PREPARE diversion.
  Revise each test program to use only library features of the
  respective standard’s freestanding environment.
  (_AC_C_STD_TRY): Take the *name* of the shell variable holding the
  complete test program as an argument, not the code itself.  All
  callers adjusted to match.

  (_AC_PROG_CXX_CXX98, _AC_PROG_CXX_CXX11, _AC_CXX_STD_TRY)
  (_AC_CXX_CXX98_TEST_HEADER, _AC_CXX_CXX98_TEST_BODY)
  (_AC_CXX_CXX11_TEST_HEADER, _AC_CXX_CXX11_TEST_BODY): Similarly.
  New macros are:
  _AC_CXX_CXX98_TEST_GLOBALS, _AC_CXX_CXX98_TEST_MAIN,
  _AC_CXX_CXX98_TEST_PROGRAM,
  _AC_CXX_CXX11_TEST_GLOBALS, _AC_CXX_CXX11_TEST_MAIN,
  _AC_CXX_CXX11_TEST_PROGRAM.
2020-12-06 16:43:26 -05:00
Zack Weinberg
b045574cb2
AC_INCLUDES_DEFAULT: Check for presence of C90 hosted headers (#110393)
Since 1993, Autoconf has been assuming that it is safe to include any
of the headers defined by ISO C90 without checking for them; this is
inaccurate, since only a subset are necessarily available in a
C90 *freestanding* environment.

It is OK to assume the presence of a header in a macro that checks
specifically for something declared by that header (if the header is
not present, we will think the specific declaration is unavailable,
which is probably accurate for modern embedded environments).  It is
also OK to continue recommending that user code use these headers
unconditionally—anyone working with a freestanding environment knows
it.  But it is not OK for very generic code within Autoconf itself,
such as AC_INCLUDES_DEFAULT, to make this assumption.

Note that the set of headers that are not always available includes
stdio.h, which we have been assuming can be included unconditionally
for even longer.

In AC_INCLUDES_DEFAULT, revert to checking for string.h and stdlib.h
before including them.  Also revert to defining STDC_HEADERS only when
string.h and stdlib.h are available (but do not check for float.h and
stdarg.h, as these are part of the freestanding set).  Add a new check
for stdio.h.  Sort the inclusion list by standard (C90 freestanding;
C90 hosted; C99; POSIX) and alphabetically within each group.  Revise
all the documentation and update the testsuite.

This partially reverts commit 86c213d0e3
and is a partial fix for bug #110393.

* lib/autoconf/headers.m4 (AC_CHECK_INCLUDES_DEFAULT): Check for
  stdio.h, stdlib.h, and string.h before including them.  Define
  STDC_HEADERS only when string.h and stdlib.h are both available.
  Organize includes list by standard, then alphabetically.

* doc/autoconf.texi, NEWS: Update to match.

* tests/local.at (AT_CHECK_DEFINES): Make regexes more specific.
  Also expect a definition of HAVE_STDIO_H.
* tests/c.at, tests/semantics.at, tests/tools.at: Use <float.h>,
  not <stdio.h>, as a header that we expect always to exist.
  Add HAVE_STDIO_H to various lists of macros that are expected to
  appear in config.h.
2020-12-06 11:40:39 -05:00
Julien ÉLIE
c467efab94
Define _NETBSD_SOURCE and _OPENBSD_SOURCE in AC_USE_SYSTEM_EXTENSIONS (#110392)
These expose additional extensions specific to those operating
systems, similar to _DARWIN_C_SOURCE, _GNU_SOURCE, etc.

(DragonflyBSD and FreeBSD currently do not have any equivalent
macros.)

Fixes bug #110392.  See also
https://git.savannah.gnu.org/cgit/gnulib.git/tree/m4/extensions.m4
https://git.eyrie.org/?p=devel/rra-c-util.git;a=commitdiff;h=f8a922cf31804dcc25ac176dcc22fdcdffcb5fdf

* lib/autoconf/specific.m4 (AC_USE_SYSTEM_EXTENSIONS): Also define
  _NETBSD_SOURCE and _OPENBSD_SOURCE.  Add comment explaining that
  there are (currently) no equivalent macros on DragonflyBSD and
  FreeBSD.  Put macro list in alphabetical order.
2020-12-06 10:53:58 -05:00
Zack Weinberg
c38538737c
Revert "AC_PROG_CC: define via AC_DEFUN_ONCE". (#110350)
Revert commit 18c140b50b, restoring
AC_PROG_CC to being defined as an ordinary AC_DEFUN.  This broke
third-party macros (e.g. the Autoconf Macro Archive’s
AX_PROG_CC_FOR_BUILD) that intentionally invoked AC_PROG_CC a second
time with its guts redefined via a whole bunch of ‘pushdef’s.  I don’t
think we want to support this long-term, but needing access to a
build-native compiler in cross-compilation is common enough that we
should have *some* supported way to do it, and it may as well be
AX_PROG_CC_FOR_BUILD until we come up with something better.

If we go back to AC_DEFUN_ONCE for AC_PROG_CC in the future, we should
do it consistently for all the “find me a compiler” macros -- it
was *only* done for AC_PROG_CC in 18c140b5.

The rationale for AC_DEFUN_ONCE seems to have been to reduce the size
of the generated configure script.  The bulk of the size accountable to
AC_PROG_CC is the test programs for figuring out which version of the
C standard is available, so I tweaked _AC_C_STD_TRY (and _AC_CXX_STD_TRY)
to emit that text only once per program, into shell variables which
can then be referenced repeatedly.

Fixes bug #110350.

* NEWS, doc/autoconf.texi: Revert documentation changes associated
  with AC_PROG_CC being a one-shot macro.
* lib/autoconf/c.m4 (AC_PROG_CC): Revert to defining with AC_DEFUN.
  (_AC_C_STD_TRY, _AC_CXX_STD_TRY): Emit the test program only once,
  even if invoked multiple times with the same arguments.

* tests/foreign.at (AX_PROG_CC_FOR_BUILD, AX_PROG_CXX_FOR_BUILD):
  New tests.
2020-12-04 16:41:43 -05:00
Zack Weinberg
2a7a441b43
Autotest: add official way to execute code before all/each test.
Currently, there isn’t any documented way for an Autotest testsuite to
add custom code to be run either right before the main driver loop, or
at the point of each AT_SETUP.  For instance, there’s no good place to
put environment variable sanitization that should apply to the entire
testsuite (but isn’t universally relevant), or shell function
definitions to be used by custom test macros.

Autoconf’s test suite is poking shell functions directly into the
PREPARE_TESTS diversion, and doing environment variable sanitization
in each individual test.  Both of these are obviously undesirable.

This patch adds three new AT_* macros that can be used to do these
things in an officially-supported way: AT_PREPARE_TESTS adds code to
be run right before the main driver loop, AT_PREPARE_EACH_TEST adds
code to be run at the beginning of each test, and AT_TEST_HELPER_FN
defines a shell function that will be available to each test.  In
Autoconf’s test suite, I use AT_PREPARE_TESTS to factor out
environment variable sanitization that *ought* to apply across the
board, and AT_TEST_HELPER_FN for the helper function used by
AT_CHECK_ENV.

(This fixes the testsuite bug reported by Jannick at
https://lists.gnu.org/archive/html/autoconf/2020-10/msg00052.html :
CONFIG_SITE in the parent environment will no longer be visible to tests.)

It would be nice to give an example of when AT_PREPARE_EACH_TEST is
useful, in the documentation, but I didn’t find one in the autoconf
test suite.

* lib/autotest/general.m4 (AT_PREPARE_TESTS, AT_PREPARE_EACH_TEST)
  (AT_TEST_HELPER_FN): New macros.
  (AT_INIT, AT_TESTED): Emit the code to report tested programs only
  if it’s needed, and make sure it’s after any code added by
  AT_PREPARE_TESTS.

* tests/local.at: Add AT_PREPARE_TESTS block that ensures
  $MAKE is set sensibly and $MAKEFLAGS and $CONFIG_SITE are unset.
  Use AT_TEST_HELPER_FN for the helper function needed by AT_CHECK_ENV.
  (AT_CHECK_MAKE): No need to sanitize $MAKE or $MAKEFLAGS here.
* tests/base.at, tests/compile.at, tests/m4sh.at, tests/torture.at:
  No need to unset or neutralize $CONFIG_SITE in individual tests.
* tests/autotest.at: Add tests for new macros.

* doc/autoconf.texi, NEWS: Document new macros.
2020-12-02 10:29:25 -05:00