Use and require C++17 instead of C++11 (in distro + sagelib)

build/bin/sage-build-env-config.in

@@ -19,7 +19,7 @@
 #
 ##########################################################################
 
-# The configured CXX without special flags added that enable C++11 support
+# The configured CXX without special flags added that enable C++17 support
 export SAGE_CXX_WITHOUT_STD="@SAGE_CXX_WITHOUT_STD@"
 
 # Export SAGE_FAT_BINARY if this was enabled during configure.

build/pkgs/brial/checksums.ini

@@ -1,4 +1,4 @@
 tarball=brial-VERSION.tar.bz2
-sha1=ea69faff56fb7068536723f3fb5b3583b8467831
-sha256=deb95fc1a99b6f9324f1278fcb676a605b77d59f24683d6af87f573cb46d0a4f
+sha1=653627fb80872cc392e6cbb4cafc9fdd22967b37
+sha256=ca009e3722dd3f0a60d15501caed1413146c80abced57423e32ae0116f407494
 upstream_url=https://github.com/BRiAl/BRiAl/releases/download/VERSION/brial-VERSION.tar.bz2

build/pkgs/brial/package-version.txt

@@ -1 +1 @@
-1.2.8
+1.2.12

build/pkgs/gcc/spkg-configure.m4

@@ -121,13 +121,13 @@ SAGE_SPKG_CONFIGURE_BASE([gcc], [
     ])
     AC_LANG_POP()
 
-    # Save the value of CXX without special flags to enable C++11 support
+    # Save the value of CXX without special flags to enable C++17 support
     AS_VAR_SET([SAGE_CXX_WITHOUT_STD], [$CXX])
     AC_SUBST(SAGE_CXX_WITHOUT_STD)
-    # Modify CXX to include an option that enables C++11 support if necessary
-    AX_CXX_COMPILE_STDCXX_11([], optional)
-    if test $HAVE_CXX11 != 1; then
-        SAGE_MUST_INSTALL_GCC([your C++ compiler does not support C++11])
+    # Modify CXX to include an option that enables C++17 support if necessary
+    AX_CXX_COMPILE_STDCXX_17([], optional)
+    if test $HAVE_CXX17 != 1; then
+        SAGE_MUST_INSTALL_GCC([your C++ compiler does not support C++17])
     fi
     AC_SUBST(CXX)
 

m4/ax_cxx_compile_stdcxx.m4

@@ -10,13 +10,13 @@
 #
 #   Check for baseline language coverage in the compiler for the specified
 #   version of the C++ standard.  If necessary, add switches to CXX and
-#   CXXCPP to enable support.  VERSION may be '11' (for the C++11 standard)
-#   or '14' (for the C++14 standard).
+#   CXXCPP to enable support.  VERSION may be '11', '14', '17', or '20' for
+#   the respective C++ standard version.
 #
 #   The second argument, if specified, indicates whether you insist on an
 #   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
 #   -std=c++11).  If neither is specified, you get whatever works, with
-#   preference for an extended mode.
+#   preference for no added switch, and then for an extended mode.
 #
 #   The third argument, if specified 'mandatory' or if left unspecified,
 #   indicates that baseline support for the specified C++ standard is
@@ -34,13 +34,16 @@
 #   Copyright (c) 2015 Paul Norman <penorman@mac.com>
 #   Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
 #   Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com>
+#   Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com>
+#   Copyright (c) 2020 Jason Merrill <jason@redhat.com>
+#   Copyright (c) 2021 Jörn Heusipp <osmanx@problemloesungsmaschine.de>
 #
 #   Copying and distribution of this file, with or without modification, are
 #   permitted in any medium without royalty provided the copyright notice
 #   and this notice are preserved.  This file is offered as-is, without any
 #   warranty.
 
-#serial 10
+#serial 18
 
 dnl  This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
 dnl  (serial version number 13).
@@ -49,6 +52,7 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
   m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"],
         [$1], [14], [ax_cxx_compile_alternatives="14 1y"],
         [$1], [17], [ax_cxx_compile_alternatives="17 1z"],
+        [$1], [20], [ax_cxx_compile_alternatives="20"],
         [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
   m4_if([$2], [], [],
         [$2], [ext], [],
@@ -61,6 +65,16 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
   AC_LANG_PUSH([C++])dnl
   ac_success=no
 
+  m4_if([$2], [], [dnl
+    AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
+		   ax_cv_cxx_compile_cxx$1,
+      [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+        [ax_cv_cxx_compile_cxx$1=yes],
+        [ax_cv_cxx_compile_cxx$1=no])])
+    if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
+      ac_success=yes
+    fi])
+
   m4_if([$2], [noext], [], [dnl
   if test x$ac_success = xno; then
     for alternative in ${ax_cxx_compile_alternatives}; do
@@ -90,9 +104,18 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
     dnl HP's aCC needs +std=c++11 according to:
     dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
     dnl Cray's crayCC needs "-h std=c++11"
+    dnl MSVC needs -std:c++NN for C++17 and later (default is C++14)
     for alternative in ${ax_cxx_compile_alternatives}; do
-      for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; do
-        cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+      for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}" MSVC; do
+        if test x"$switch" = xMSVC; then
+          dnl AS_TR_SH maps both `:` and `=` to `_` so -std:c++17 would collide
+          dnl with -std=c++17.  We suffix the cache variable name with _MSVC to
+          dnl avoid this.
+          switch=-std:c++${alternative}
+          cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_${switch}_MSVC])
+        else
+          cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+        fi
         AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
                        $cachevar,
           [ac_save_CXX="$CXX"
@@ -139,20 +162,31 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
 )
 
-
 dnl  Test body for checking C++14 support
 
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
 )
 
+dnl  Test body for checking C++17 support
+
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17],
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
   _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
 )
 
+dnl  Test body for checking C++20 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_20],
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
+  _AX_CXX_COMPILE_STDCXX_testbody_new_in_20
+)
+
+
 dnl  Tests for new features in C++11
 
 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
@@ -164,7 +198,11 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
 
 #error "This is not a C++ compiler"
 
-#elif __cplusplus < 201103L
+// MSVC always sets __cplusplus to 199711L in older versions; newer versions
+// only set it correctly if /Zc:__cplusplus is specified as well as a
+// /std:c++NN switch:
+// https://devblogs.microsoft.com/cppblog/msvc-now-correctly-reports-__cplusplus/
+#elif __cplusplus < 201103L && !defined _MSC_VER
 
 #error "This is not a C++11 compiler"
 
@@ -189,11 +227,13 @@ namespace cxx11
 
     struct Base
     {
+      virtual ~Base() {}
       virtual void f() {}
     };
 
     struct Derived : public Base
     {
+      virtual ~Derived() override {}
       virtual void f() override {}
     };
 
@@ -453,7 +493,7 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
 
 #error "This is not a C++ compiler"
 
-#elif __cplusplus < 201402L
+#elif __cplusplus < 201402L && !defined _MSC_VER
 
 #error "This is not a C++14 compiler"
 
@@ -577,7 +617,7 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[
 
 #error "This is not a C++ compiler"
 
-#elif __cplusplus < 201703L
+#elif __cplusplus < 201703L && !defined _MSC_VER
 
 #error "This is not a C++17 compiler"
 
@@ -943,6 +983,36 @@ namespace cxx17
 
 }  // namespace cxx17
 
-#endif  // __cplusplus < 201703L
+#endif  // __cplusplus < 201703L && !defined _MSC_VER
+
+]])
+
+
+dnl  Tests for new features in C++20
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_20], [[
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 202002L && !defined _MSC_VER
+
+#error "This is not a C++20 compiler"
+
+#else
+
+#include <version>
+
+namespace cxx20
+{
+
+// As C++20 supports feature test macros in the standard, there is no
+// immediate need to actually test for feature availability on the
+// Autoconf side.
+
+}  // namespace cxx20
+
+#endif  // __cplusplus < 202002L && !defined _MSC_VER
 
 ]])

m4/ax_cxx_compile_stdcxx_11.m4 → m4/ax_cxx_compile_stdcxx_17.m4

@@ -1,39 +1,35 @@
 # =============================================================================
-#  https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html
+#  https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_17.html
 # =============================================================================
 #
 # SYNOPSIS
 #
-#   AX_CXX_COMPILE_STDCXX_11([ext|noext], [mandatory|optional])
+#   AX_CXX_COMPILE_STDCXX_17([ext|noext], [mandatory|optional])
 #
 # DESCRIPTION
 #
-#   Check for baseline language coverage in the compiler for the C++11
+#   Check for baseline language coverage in the compiler for the C++17
 #   standard; if necessary, add switches to CXX and CXXCPP to enable
 #   support.
 #
 #   This macro is a convenience alias for calling the AX_CXX_COMPILE_STDCXX
-#   macro with the version set to C++11.  The two optional arguments are
+#   macro with the version set to C++17.  The two optional arguments are
 #   forwarded literally as the second and third argument respectively.
 #   Please see the documentation for the AX_CXX_COMPILE_STDCXX macro for
 #   more information.  If you want to use this macro, you also need to
 #   download the ax_cxx_compile_stdcxx.m4 file.
 #
 # LICENSE
 #
-#   Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
-#   Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
-#   Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
-#   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
-#   Copyright (c) 2015 Paul Norman <penorman@mac.com>
 #   Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
+#   Copyright (c) 2016 Krzesimir Nowak <qdlacz@gmail.com>
 #
 #   Copying and distribution of this file, with or without modification, are
 #   permitted in any medium without royalty provided the copyright notice
 #   and this notice are preserved. This file is offered as-is, without any
 #   warranty.
 
-#serial 18
+#serial 2
 
 AX_REQUIRE_DEFINED([AX_CXX_COMPILE_STDCXX])
-AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [AX_CXX_COMPILE_STDCXX([11], [$1], [$2])])
+AC_DEFUN([AX_CXX_COMPILE_STDCXX_17], [AX_CXX_COMPILE_STDCXX([17], [$1], [$2])])

m4/sage_check_python_for_venv.m4

@@ -92,7 +92,7 @@ AC_DEFUN([SAGE_PYTHON_CHECK_DISTUTILS], [
         echo PYTHON_EXE conftest.py --verbose build --build-base=conftest.dir >& AS_MESSAGE_LOG_FD 2>&1
         AS_IF([PYTHON_EXE conftest.py --verbose build --build-base=conftest.dir >& AS_MESSAGE_LOG_FD 2>&1 ], [
             COMMANDS_IF_DISTUTILS_GOOD], [
-            reason="distutils cannot build a C++ 11 extension"
+            reason="distutils cannot build a C++ 17 extension"
             COMMANDS_IF_DISTUTILS_NOT_GOOD
         ])
     ], [
@@ -172,16 +172,12 @@ PyInit_spam(void)
     m = PyModule_Create(&spammodule);
     return m;
 }
-// Partial C++11 test, from ax_cxx_compile_stdcxx.m4
+// Partial C++17 test, from ax_cxx_compile_stdcxx.m4
 
-  namespace test_noexcept
+  namespace test_constexpr_lambdas
   {
 
-    int f() { return 0; }
-    int g() noexcept { return 0; }
-
-    static_assert(noexcept(f()) == false, "");
-    static_assert(noexcept(g()) == true, "");
+    constexpr int foo = [](){return 42;}();
 
   }
 
@@ -194,7 +190,7 @@ from $distutils_core import setup
 from $distutils_extension import Extension
 from sys import exit
 modules = list((Extension("config_check_distutils_cxx", list(("conftest.cpp",)),
-                          extra_compile_args=list(("-std=c++11",)), language="c++"),))
+                          extra_compile_args=list(("-std=c++17",)), language="c++"),))
 setup(name="config_check_distutils_cxx", ext_modules=modules)
 exit(0)
 EOF

src/sage/env.py

@@ -474,16 +474,18 @@ def uname_specific(name, value, alternative):
     # file (possibly because of confusion between CFLAGS and CXXFLAGS?).
     # This is not a problem in practice since LinBox depends on
     # fflas-ffpack and fflas-ffpack does add such a C++11 flag.
+    #
+    # Based on the above, we have updated mechanically from -std=gnu++11 to -std=gnu++17.
     if "LINBOX_CFLAGS" in aliases:
-        aliases["LINBOX_CFLAGS"].append("-std=gnu++11")
+        aliases["LINBOX_CFLAGS"].append("-std=gnu++17")
 
     try:
         aliases["M4RI_CFLAGS"].remove("-pedantic")
     except (ValueError, KeyError):
         pass
 
     # NTL
-    aliases["NTL_CFLAGS"] = ['-std=c++11']
+    aliases["NTL_CFLAGS"] = ['-std=c++17']
     aliases["NTL_INCDIR"] = [NTL_INCDIR] if NTL_INCDIR else []
     aliases["NTL_LIBDIR"] = [NTL_LIBDIR] if NTL_LIBDIR else []
     aliases["NTL_LIBRARIES"] = ['ntl']

src/sage/graphs/base/boost_graph.pxd

@@ -1,5 +1,5 @@
 # distutils: language = c++
-# distutils: extra_compile_args = -std=c++11
+# distutils: extra_compile_args = -std=c++17
 
 #*****************************************************************************
 #       Copyright (C) 2015 Michele Borassi michele.borassi@imtlucca.it

src/sage/graphs/bliss.pyx

@@ -1,5 +1,5 @@
 # distutils: language = c++
-# distutils: extra_compile_args = -std=c++11
+# distutils: extra_compile_args = -std=c++17
 # distutils: libraries = bliss
 # sage_setup: distribution = sagemath-bliss
 

src/sage/graphs/graph_decompositions/tdlib.pyx

@@ -1,5 +1,5 @@
 # distutils: language = c++
-# distutils: extra_compile_args = -std=c++11
+# distutils: extra_compile_args = -std=c++17
 # sage_setup: distribution = sagemath-tdlib
 
 r"""

src/sage/libs/m4ri.pxd

@@ -1,4 +1,4 @@
-# distutils: extra_compile_args = -std=c++11
+# distutils: extra_compile_args = -std=c++17
 # distutils: language = c++
 
 cdef extern from "m4ri/m4ri.h":

src/sage/libs/polybori/decl.pxd

@@ -1,5 +1,5 @@
 # distutils: language = c++
-# distutils: extra_compile_args = -std=c++11
+# distutils: extra_compile_args = -std=c++17
 
 from libcpp.string cimport string as std_string
 from libcpp.vector cimport vector

src/sage/libs/singular/decl.pxd

@@ -3,7 +3,7 @@
 # distutils: libraries = SINGULAR_LIBRARIES
 # distutils: library_dirs = SINGULAR_LIBDIR
 # distutils: language = c++
-# distutils: extra_compile_args = -std=c++11
+# distutils: extra_compile_args = -std=c++17
 """
 Declarations of Singular's C/C++ Functions
 

src/sage/modular/arithgroup/farey_symbol.pyx

@@ -1,6 +1,6 @@
 # distutils: sources = sage/modular/arithgroup/sl2z.cpp sage/modular/arithgroup/farey.cpp
 # distutils: language = c++
-# distutils: extra_compile_args = -std=c++11
+# distutils: extra_compile_args = -std=c++17
 # sage.doctest: needs sage.libs.pari
 r"""
 Farey symbol for arithmetic subgroups of `\PSL_2(\ZZ)`