[gcc r11-6137] libstdc++: Test errno macros directly, not via autoconf [PR 93151]

[gcc r11-6137] libstdc++: Test errno macros directly, not via autoconf [PR 93151]

[Jonathan Wakely]

https://gcc.gnu.org/g:a2c2eec183acf25c9b214fa0827718e4d2fdfc93

commit r11-6137-ga2c2eec183acf25c9b214fa0827718e4d2fdfc93
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Dec 15 20:28:11 2020 +0000

    libstdc++: Test errno macros directly, not via autoconf [PR 93151]
    
    This fixes a bug caused by a mismatch between the macros defined by
    <errno.h> when GCC is built and the macros defined by <errno.h> when
    users include <system_error>. If the user code is compiled with
    _XOPEN_SOURCE defined to 500 or 600, Darwin suppresses the
    ENOTRECOVERABLE and EOWNERDEAD macros, which are not defined by SUSv3
    (aka POSIX.1-2001).
    
    Since POSIX requires the errno macros to be macros (and not variables or
    enumerators) we can just test for them directly using the preprocessor.
    That means that <system_error> will match what is actuallydefined when
    it's included, not what was defined when GCC was built. With that change
    there is no need for the GLIBCXX_CHECK_SYSTEM_ERROR configure checks and
    they can be removed.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/93151
            * acinclude.m4 (GLIBCXX_CHECK_SYSTEM_ERROR): Remove.
            * configure.ac: Regenerate.
            * config/os/generic/error_constants.h: Test POSIX errno macros
            directly, instead of corresponding _GLIBCXX_HAVE_EXXX macros.
            * testsuite/19_diagnostics/headers/system_error/errc_std_c++0x.cc:
            Likewise.
            * testsuite/19_diagnostics/headers/system_error/93151.cc: New
            test.

Diff:
---
 libstdc++-v3/acinclude.m4                          | 29 --------------------
 libstdc++-v3/config/os/generic/error_constants.h   | 28 +++++++++----------
 libstdc++-v3/configure.ac                          |  1 -
 .../19_diagnostics/headers/system_error/93151.cc   | 23 ++++++++++++++++
 .../headers/system_error/errc_std_c++0x.cc         | 32 +++++++++++-----------
 5 files changed, 53 insertions(+), 60 deletions(-)

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index df8be3bf805..e4175ea3e64 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -2372,35 +2372,6 @@ AC_DEFUN([GLIBCXX_CHECK_MATH11_PROTO], [
   AC_LANG_RESTORE
 ])
 
-dnl
-dnl Check whether macros, etc are present for <system_error>
-dnl
-AC_DEFUN([GLIBCXX_CHECK_SYSTEM_ERROR], [
-
-m4_pushdef([n_syserr], [1])dnl
-m4_foreach([syserr], [EOWNERDEAD, ENOTRECOVERABLE, ENOLINK, EPROTO, ENODATA,
-		      ENOSR, ENOSTR, ETIME, EBADMSG, ECANCELED,
-		      EOVERFLOW, ENOTSUP, EIDRM, ETXTBSY,
-		      ECHILD, ENOSPC, EPERM,
-		      ETIMEDOUT, EWOULDBLOCK],
-[m4_pushdef([SYSERR], m4_toupper(syserr))dnl
-AC_MSG_CHECKING([for syserr])
-AC_CACHE_VAL([glibcxx_cv_system_error[]n_syserr], [
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <errno.h>]],
-				   [int i = syserr;])],
-		  [glibcxx_cv_system_error[]n_syserr=yes],
-		  [glibcxx_cv_system_error[]n_syserr=no])
-])
-AC_MSG_RESULT([$glibcxx_cv_system_error[]n_syserr])
-if test x"$glibcxx_cv_system_error[]n_syserr" = x"yes"; then
-  AC_DEFINE([HAVE_]SYSERR, 1, [Define if ]syserr[ exists.])
-fi
-m4_define([n_syserr], m4_incr(n_syserr))dnl
-m4_popdef([SYSERR])dnl
-])
-m4_popdef([n_syserr])dnl
-])
-
 dnl
 dnl Check for what type of C headers to use.
 dnl
diff --git a/libstdc++-v3/config/os/generic/error_constants.h b/libstdc++-v3/config/os/generic/error_constants.h
index b5b0ea6b9ad..0d34f7179b6 100644
--- a/libstdc++-v3/config/os/generic/error_constants.h
+++ b/libstdc++-v3/config/os/generic/error_constants.h
@@ -48,7 +48,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       bad_address = 				EFAULT,
       bad_file_descriptor = 			EBADF,
 
-#ifdef _GLIBCXX_HAVE_EBADMSG
+#ifdef EBADMSG
       bad_message = 				EBADMSG,
 #endif
 
@@ -68,7 +68,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       function_not_supported = 			ENOSYS,
       host_unreachable = 			EHOSTUNREACH,
 
-#ifdef _GLIBCXX_HAVE_EIDRM
+#ifdef EIDRM
       identifier_removed = 			EIDRM,
 #endif
 
@@ -86,13 +86,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       no_buffer_space = 			ENOBUFS,
       no_child_process = 			ECHILD,
 
-#ifdef _GLIBCXX_HAVE_ENOLINK
+#ifdef ENOLINK
       no_link = 				ENOLINK,
 #endif
 
       no_lock_available = 			ENOLCK,
 
-#ifdef _GLIBCXX_HAVE_ENODATA
+#ifdef ENODATA
       no_message_available = 			ENODATA,
 #endif
 
@@ -100,7 +100,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       no_protocol_option = 			ENOPROTOOPT,
       no_space_on_device = 			ENOSPC,
 
-#ifdef _GLIBCXX_HAVE_ENOSR
+#ifdef ENOSR
       no_stream_resources = 			ENOSR,
 #endif
 
@@ -111,18 +111,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       not_a_directory = 			ENOTDIR,
       not_a_socket = 				ENOTSOCK,
 
-#ifdef _GLIBCXX_HAVE_ENOSTR
+#ifdef ENOSTR
       not_a_stream = 				ENOSTR,
 #endif
 
       not_connected = 				ENOTCONN,
       not_enough_memory = 			ENOMEM,
 
-#ifdef _GLIBCXX_HAVE_ENOTSUP
+#ifdef ENOTSUP
       not_supported = 				ENOTSUP,
 #endif
 
-#ifdef _GLIBCXX_HAVE_ECANCELED
+#ifdef ECANCELED
       operation_canceled = 			ECANCELED,
 #endif
 
@@ -131,13 +131,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       operation_not_supported = 		EOPNOTSUPP,
       operation_would_block = 			EWOULDBLOCK,
 
-#ifdef _GLIBCXX_HAVE_EOWNERDEAD
+#ifdef EOWNERDEAD
       owner_dead = 				EOWNERDEAD,
 #endif
 
       permission_denied = 			EACCES,
 
-#ifdef _GLIBCXX_HAVE_EPROTO
+#ifdef EPROTO
       protocol_error = 				EPROTO,
 #endif
 
@@ -147,15 +147,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       resource_unavailable_try_again = 		EAGAIN,
       result_out_of_range = 			ERANGE,
 
-#ifdef _GLIBCXX_HAVE_ENOTRECOVERABLE
+#ifdef ENOTRECOVERABLE
       state_not_recoverable = 			ENOTRECOVERABLE,
 #endif
 
-#ifdef _GLIBCXX_HAVE_ETIME
+#ifdef ETIME
       stream_timeout = 				ETIME,
 #endif
 
-#ifdef _GLIBCXX_HAVE_ETXTBSY
+#ifdef ETXTBSY
       text_file_busy = 				ETXTBSY,
 #endif
 
@@ -165,7 +165,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       too_many_links = 				EMLINK,
       too_many_symbolic_link_levels = 		ELOOP,
 
-#ifdef _GLIBCXX_HAVE_EOVERFLOW
+#ifdef EOVERFLOW
       value_too_large = 			EOVERFLOW,
 #endif
 
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index 771814110a1..9138ba22588 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -183,7 +183,6 @@ GLIBCXX_ENABLE_VTABLE_VERIFY([no])
 # Checks for operating systems support that doesn't require linking.
 GLIBCXX_CHECK_STDIO_PROTO
 GLIBCXX_CHECK_MATH11_PROTO
-GLIBCXX_CHECK_SYSTEM_ERROR
 GLIBCXX_CHECK_UCHAR_H
 
 # For the streamoff typedef.
diff --git a/libstdc++-v3/testsuite/19_diagnostics/headers/system_error/93151.cc b/libstdc++-v3/testsuite/19_diagnostics/headers/system_error/93151.cc
new file mode 100644
index 00000000000..2d8efc76deb
--- /dev/null
+++ b/libstdc++-v3/testsuite/19_diagnostics/headers/system_error/93151.cc
@@ -0,0 +1,23 @@
+// { dg-do compile { target c++11 } }
+
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// PR libstdc++/93151
+#undef _XOPEN_SOURCE
+#define _XOPEN_SOURCE 600
+#include <system_error>
diff --git a/libstdc++-v3/testsuite/19_diagnostics/headers/system_error/errc_std_c++0x.cc b/libstdc++-v3/testsuite/19_diagnostics/headers/system_error/errc_std_c++0x.cc
index 0f006ae47d9..72c4b53124d 100644
--- a/libstdc++-v3/testsuite/19_diagnostics/headers/system_error/errc_std_c++0x.cc
+++ b/libstdc++-v3/testsuite/19_diagnostics/headers/system_error/errc_std_c++0x.cc
@@ -34,7 +34,7 @@ void test01()
   TEST_ERRC(bad_address);
   TEST_ERRC(bad_file_descriptor);
 
-#ifdef _GLIBCXX_HAVE_EBADMSG
+#ifdef EBADMSG
   TEST_ERRC(bad_message);
 #endif
 
@@ -54,7 +54,7 @@ void test01()
   TEST_ERRC(function_not_supported);
   TEST_ERRC(host_unreachable);
 
-#ifdef _GLIBCXX_HAVE_EIDRM
+#ifdef EIDRM
   TEST_ERRC(identifier_removed);
 #endif
 
@@ -72,23 +72,23 @@ void test01()
   TEST_ERRC(no_buffer_space);
   TEST_ERRC(no_child_process);
 
-#ifdef _GLIBCXX_HAVE_ENOLINK
+#ifdef ENOLINK
   TEST_ERRC(no_link);
 #endif
 
   TEST_ERRC(no_lock_available);
 
-#ifdef _GLIBCXX_HAVE_ENODATA
+#ifdef ENODATA
   TEST_ERRC(no_message_available);
 #endif
 
-#ifdef _GLIBCXX_HAVE_ENOMSG
+#ifdef ENOMSG
   TEST_ERRC(no_message);
 #endif
   TEST_ERRC(no_protocol_option);
   TEST_ERRC(no_space_on_device);
 
-#ifdef _GLIBCXX_HAVE_ENOSR
+#ifdef ENOSR
   TEST_ERRC(no_stream_resources);
 #endif
 
@@ -99,15 +99,15 @@ void test01()
   TEST_ERRC(not_a_directory);
   TEST_ERRC(not_a_socket);
 
-#ifdef _GLIBCXX_HAVE_ENOSTR
+#ifdef ENOSTR
   TEST_ERRC(not_a_stream);
 #endif
 
-  TEST_ERRC(not_connected); 
+  TEST_ERRC(not_connected);
   TEST_ERRC(not_enough_memory);
   TEST_ERRC(not_supported);
 
-#ifdef _GLIBCXX_HAVE_ECANCELED
+#ifdef ECANCELED
   TEST_ERRC(operation_canceled);
 #endif
 
@@ -116,31 +116,31 @@ void test01()
   TEST_ERRC(operation_not_supported);
   TEST_ERRC(operation_would_block);
 
-#ifdef _GLIBCXX_HAVE_EOWNERDEAD
+#ifdef EOWNERDEAD
   TEST_ERRC(owner_dead);
 #endif
 
   TEST_ERRC(permission_denied);
 
-#ifdef _GLIBCXX_HAVE_EPROTO
+#ifdef EPROTO
   TEST_ERRC(protocol_error);
 #endif
 
   TEST_ERRC(protocol_not_supported);
   TEST_ERRC(read_only_file_system);
   TEST_ERRC(resource_deadlock_would_occur);
-  TEST_ERRC(resource_unavailable_try_again); 
+  TEST_ERRC(resource_unavailable_try_again);
   TEST_ERRC(result_out_of_range);
 
-#ifdef _GLIBCXX_HAVE_ENOTRECOVERABLE
+#ifdef ENOTRECOVERABLE
   TEST_ERRC(state_not_recoverable);
 #endif
 
-#ifdef _GLIBCXX_HAVE_ETIME
+#ifdef ETIME
   TEST_ERRC(stream_timeout);
 #endif
 
-#ifdef _GLIBCXX_HAVE_ETXTBSY
+#ifdef ETXTBSY
   TEST_ERRC(text_file_busy);
 #endif
 
@@ -150,7 +150,7 @@ void test01()
   TEST_ERRC(too_many_links);
   TEST_ERRC(too_many_symbolic_link_levels);
 
-#ifdef _GLIBCXX_HAVE_EOVERFLOW
+#ifdef EOVERFLOW
   TEST_ERRC(value_too_large);
 #endif