On 5/15/20 2:21 PM, Richard Biener wrote:
On May 15, 2020 7:30:38 PM GMT+02:00, Jason Merrill <ja...@redhat.com> wrote:
On Fri, May 15, 2020 at 3:15 AM Richard Biener
<richard.guent...@gmail.com>
wrote:
+# When bootstrapping with GCC, build stage 1 in C++11 mode to
ensure
that a
+# C++11 compiler can still start the bootstrap.
if test "$enable_bootstrap:$GXX" = "yes:yes"; then
+ CXX="$CXX -std=gnu++11"
So I just spotted this - since we're requiring a ISO C++11 compiler shouldn't
we build stage1 with -std=c++11 rather than gnu++11 (whatever the detailed
differences are here)? Also not sure what level of -pedantic we'd need to
avoid GNU extensions even with -std=c++11. Of course there are (I hope)
a lot less GNU extensions for C++ than there were for C and hopefully
no extra in gnu++11 compared to gnu++98 which we checked previously.
Building stage 1 with -std=c++11 -pedantic-errors works with 8.3.1, but
fails pretty badly with 4.8.5,
When we first moved to C++ I tried using -std=c++98, but there were too
many places where we were assuming that if we're building with GCC, we can
use GNU C extensions.
I'll see if that's still a problem for -std=c++11.
It doesn't seem to be, so I've made that change.
There also does not seem to be a configure check which may present
users with a more useful error message than later cryptic fail of build?
I suppose we cannot simply check __cplusplus for this, can we? Do
other common host compilers need additional options to enable C++11?
Good point, I'll add that.
This patch uses a test from the autoconf archive to add any needed
flags. Tested with GCC 4.8.5 and clang 3.4.2 (with the above stage 1
-std=c++11 disabled).
Should we try to second guess such flags via configury? For example
GCC 4.8 defaults to -std=gnu++98 and the above only seems to apply
to the bootstrap case so GCC 4.8 cannot be used to build cross
compilers
without adjusting CC and CXX?
Older GCC is still GCC and will get the flag automatically.
But yes:yes suggests that when building a cross compiler this doesn't apply?
True, but the new test should cover that case.
OK for trunk?
commit f466a9f3f121f16b97071162806255fb464718f2
Author: Jason Merrill <ja...@redhat.com>
Date: Fri May 15 17:15:38 2020 -0400
bootstrap: Update requirement to C++11.
There was general agreement last November that we would move to allowing
C++11 features to be used in GCC 11; this patch implements that direction.
ChangeLog
2020-05-15 Jason Merrill <ja...@redhat.com>
* configure.ac: Update bootstrap dialect to -std=c++11.
config/ChangeLog
2020-05-15 Jason Merrill <ja...@redhat.com>
* ax_cxx_compile_stdcxx.m4: Import from autoconf archive with
an adjustment to try the default mode.
gcc/ChangeLog
2020-05-15 Jason Merrill <ja...@redhat.com>
* aclocal.m4: Add ax_cxx_compile_stdcxx.m4.
* configure.ac: Use AX_CXX_COMPILE_STDCXX(11).
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 876b04f9c45..c367f4f66e3 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -238,18 +238,20 @@ described below.
@heading Tools/packages necessary for building GCC
@table @asis
-@item ISO C++98 compiler
-Necessary to bootstrap GCC, although versions of GCC prior
-to 4.8 also allow bootstrapping with a ISO C89 compiler and versions
-of GCC prior to 3.4 also allow bootstrapping with a traditional
-(K&R) C compiler.
+@item ISO C++11 compiler
+Necessary to bootstrap GCC.
+
+Versions of GCC prior to 11 also allow bootstrapping with an ISO C++98
+compiler, versions of GCC prior to 4.8 also allow bootstrapping with a
+ISO C89 compiler, and versions of GCC prior to 3.4 also allow
+bootstrapping with a traditional (K&R) C compiler.
To build all languages in a cross-compiler or other configuration where
3-stage bootstrap is not performed, you need to start with an existing
-GCC binary (version 3.4 or later) because source code for language
+GCC binary (version 4.8 or later) because source code for language
frontends other than C might use GCC extensions.
-Note that to bootstrap GCC with versions of GCC earlier than 3.4, you
+Note that to bootstrap GCC with versions of GCC earlier than 4.8, you
may need to use @option{--disable-stage1-checking}, though
bootstrapping the compiler with such earlier compilers is strongly
discouraged.
diff --git a/config/ax_cxx_compile_stdcxx.m4 b/config/ax_cxx_compile_stdcxx.m4
new file mode 100644
index 00000000000..9413da624d2
--- /dev/null
+++ b/config/ax_cxx_compile_stdcxx.m4
@@ -0,0 +1,962 @@
+# ===========================================================================
+# https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+# AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
+#
+# DESCRIPTION
+#
+# 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).
+#
+# 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 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
+# required and that the macro should error out if no mode with that
+# support is found. If specified 'optional', then configuration proceeds
+# regardless, after defining HAVE_CXX${VERSION} if and only if a
+# supporting mode is found.
+#
+# LICENSE
+#
+# Copyright (c) 2008 Benjamin Kosnik <b...@redhat.com>
+# Copyright (c) 2012 Zack Weinberg <za...@panix.com>
+# Copyright (c) 2013 Roy Stogner <royst...@ices.utexas.edu>
+# Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <soko...@google.com>
+# Copyright (c) 2015 Paul Norman <penor...@mac.com>
+# Copyright (c) 2015 Moritz Klammler <mor...@klammler.eu>
+# Copyright (c) 2016, 2018 Krzesimir Nowak <qdl...@gmail.com>
+# Copyright (c) 2019 Enji Cooper <yaneurab...@gmail.com>
+# Copyright (c) 2020 Jason Merrill <ja...@redhat.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 12
+
+dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
+dnl (serial version number 13).
+
+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"],
+ [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
+ m4_if([$2], [], [],
+ [$2], [ext], [],
+ [$2], [noext], [],
+ [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
+ m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
+ [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
+ [$3], [optional], [ax_cxx_compile_cxx$1_required=false],
+ [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
+ 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 ${ax_cxx_compile_alternatives}; do
+ switch="-std=gnu++${alternative}"
+ cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+ AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+ $cachevar,
+ [ac_save_CXX="$CXX"
+ CXX="$CXX $switch"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+ [eval $cachevar=yes],
+ [eval $cachevar=no])
+ CXX="$ac_save_CXX"])
+ if eval test x\$$cachevar = xyes; then
+ CXX="$CXX $switch"
+ if test -n "$CXXCPP" ; then
+ CXXCPP="$CXXCPP $switch"
+ fi
+ ac_success=yes
+ break
+ fi
+ done
+ fi])
+
+ m4_if([$2], [ext], [], [dnl
+ if test x$ac_success = xno; then
+ 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"
+ 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])
+ AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+ $cachevar,
+ [ac_save_CXX="$CXX"
+ CXX="$CXX $switch"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+ [eval $cachevar=yes],
+ [eval $cachevar=no])
+ CXX="$ac_save_CXX"])
+ if eval test x\$$cachevar = xyes; then
+ CXX="$CXX $switch"
+ if test -n "$CXXCPP" ; then
+ CXXCPP="$CXXCPP $switch"
+ fi
+ ac_success=yes
+ break
+ fi
+ done
+ if test x$ac_success = xyes; then
+ break
+ fi
+ done
+ fi])
+ AC_LANG_POP([C++])
+ if test x$ax_cxx_compile_cxx$1_required = xtrue; then
+ if test x$ac_success = xno; then
+ AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.])
+ fi
+ fi
+ if test x$ac_success = xno; then
+ HAVE_CXX$1=0
+ AC_MSG_NOTICE([No compiler with C++$1 support was found])
+ else
+ HAVE_CXX$1=1
+ AC_DEFINE(HAVE_CXX$1,1,
+ [define if the compiler supports basic C++$1 syntax])
+ fi
+ AC_SUBST(HAVE_CXX$1)
+])
+
+
+dnl Test body for checking C++11 support
+
+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
+)
+
+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 Tests for new features in C++11
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
+
+// If the compiler admits that it is not ready for C++11, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201103L
+
+#error "This is not a C++11 compiler"
+
+#else
+
+namespace cxx11
+{
+
+ namespace test_static_assert
+ {
+
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ }
+
+ namespace test_final_override
+ {
+
+ struct Base
+ {
+ virtual ~Base() {}
+ virtual void f() {}
+ };
+
+ struct Derived : public Base
+ {
+ virtual ~Derived() override {}
+ virtual void f() override {}
+ };
+
+ }
+
+ namespace test_double_right_angle_brackets
+ {
+
+ template < typename T >
+ struct check {};
+
+ typedef check<void> single_type;
+ typedef check<check<void>> double_type;
+ typedef check<check<check<void>>> triple_type;
+ typedef check<check<check<check<void>>>> quadruple_type;
+
+ }
+
+ namespace test_decltype
+ {
+
+ int
+ f()
+ {
+ int a = 1;
+ decltype(a) b = 2;
+ return a + b;
+ }
+
+ }
+
+ namespace test_type_deduction
+ {
+
+ template < typename T1, typename T2 >
+ struct is_same
+ {
+ static const bool value = false;
+ };
+
+ template < typename T >
+ struct is_same<T, T>
+ {
+ static const bool value = true;
+ };
+
+ template < typename T1, typename T2 >
+ auto
+ add(T1 a1, T2 a2) -> decltype(a1 + a2)
+ {
+ return a1 + a2;
+ }
+
+ int
+ test(const int c, volatile int v)
+ {
+ static_assert(is_same<int, decltype(0)>::value == true, "");
+ static_assert(is_same<int, decltype(c)>::value == false, "");
+ static_assert(is_same<int, decltype(v)>::value == false, "");
+ auto ac = c;
+ auto av = v;
+ auto sumi = ac + av + 'x';
+ auto sumf = ac + av + 1.0;
+ static_assert(is_same<int, decltype(ac)>::value == true, "");
+ static_assert(is_same<int, decltype(av)>::value == true, "");
+ static_assert(is_same<int, decltype(sumi)>::value == true, "");
+ static_assert(is_same<int, decltype(sumf)>::value == false, "");
+ static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
+ return (sumf > 0.0) ? sumi : add(c, v);
+ }
+
+ }
+
+ namespace test_noexcept
+ {
+
+ int f() { return 0; }
+ int g() noexcept { return 0; }
+
+ static_assert(noexcept(f()) == false, "");
+ static_assert(noexcept(g()) == true, "");
+
+ }
+
+ namespace test_constexpr
+ {
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
+ {
+ return *s ? strlen_c_r(s + 1, acc + 1) : acc;
+ }
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c(const CharT *const s) noexcept
+ {
+ return strlen_c_r(s, 0UL);
+ }
+
+ static_assert(strlen_c("") == 0UL, "");
+ static_assert(strlen_c("1") == 1UL, "");
+ static_assert(strlen_c("example") == 7UL, "");
+ static_assert(strlen_c("another\0example") == 7UL, "");
+
+ }
+
+ namespace test_rvalue_references
+ {
+
+ template < int N >
+ struct answer
+ {
+ static constexpr int value = N;
+ };
+
+ answer<1> f(int&) { return answer<1>(); }
+ answer<2> f(const int&) { return answer<2>(); }
+ answer<3> f(int&&) { return answer<3>(); }
+
+ void
+ test()
+ {
+ int i = 0;
+ const int c = 0;
+ static_assert(decltype(f(i))::value == 1, "");
+ static_assert(decltype(f(c))::value == 2, "");
+ static_assert(decltype(f(0))::value == 3, "");
+ }
+
+ }
+
+ namespace test_uniform_initialization
+ {
+
+ struct test
+ {
+ static const int zero {};
+ static const int one {1};
+ };
+
+ static_assert(test::zero == 0, "");
+ static_assert(test::one == 1, "");
+
+ }
+
+ namespace test_lambdas
+ {
+
+ void
+ test1()
+ {
+ auto lambda1 = [](){};
+ auto lambda2 = lambda1;
+ lambda1();
+ lambda2();
+ }
+
+ int
+ test2()
+ {
+ auto a = [](int i, int j){ return i + j; }(1, 2);
+ auto b = []() -> int { return '0'; }();
+ auto c = [=](){ return a + b; }();
+ auto d = [&](){ return c; }();
+ auto e = [a, &b](int x) mutable {
+ const auto identity = [](int y){ return y; };
+ for (auto i = 0; i < a; ++i)
+ a += b--;
+ return x + identity(a + b);
+ }(0);
+ return a + b + c + d + e;
+ }
+
+ int
+ test3()
+ {
+ const auto nullary = [](){ return 0; };
+ const auto unary = [](int x){ return x; };
+ using nullary_t = decltype(nullary);
+ using unary_t = decltype(unary);
+ const auto higher1st = [](nullary_t f){ return f(); };
+ const auto higher2nd = [unary](nullary_t f1){
+ return [unary, f1](unary_t f2){ return f2(unary(f1())); };
+ };
+ return higher1st(nullary) + higher2nd(nullary)(unary);
+ }
+
+ }
+
+ namespace test_variadic_templates
+ {
+
+ template <int...>
+ struct sum;
+
+ template <int N0, int... N1toN>
+ struct sum<N0, N1toN...>
+ {
+ static constexpr auto value = N0 + sum<N1toN...>::value;
+ };
+
+ template <>
+ struct sum<>
+ {
+ static constexpr auto value = 0;
+ };
+
+ static_assert(sum<>::value == 0, "");
+ static_assert(sum<1>::value == 1, "");
+ static_assert(sum<23>::value == 23, "");
+ static_assert(sum<1, 2>::value == 3, "");
+ static_assert(sum<5, 5, 11>::value == 21, "");
+ static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
+
+ }
+
+ // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+ // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
+ // because of this.
+ namespace test_template_alias_sfinae
+ {
+
+ struct foo {};
+
+ template<typename T>
+ using member = typename T::member_type;
+
+ template<typename T>
+ void func(...) {}
+
+ template<typename T>
+ void func(member<T>*) {}
+
+ void test();
+
+ void test() { func<foo>(0); }
+
+ }
+
+} // namespace cxx11
+
+#endif // __cplusplus >= 201103L
+
+]])
+
+
+dnl Tests for new features in C++14
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
+
+// If the compiler admits that it is not ready for C++14, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201402L
+
+#error "This is not a C++14 compiler"
+
+#else
+
+namespace cxx14
+{
+
+ namespace test_polymorphic_lambdas
+ {
+
+ int
+ test()
+ {
+ const auto lambda = [](auto&&... args){
+ const auto istiny = [](auto x){
+ return (sizeof(x) == 1UL) ? 1 : 0;
+ };
+ const int aretiny[] = { istiny(args)... };
+ return aretiny[0];
+ };
+ return lambda(1, 1L, 1.0f, '1');
+ }
+
+ }
+
+ namespace test_binary_literals
+ {
+
+ constexpr auto ivii = 0b0000000000101010;
+ static_assert(ivii == 42, "wrong value");
+
+ }
+
+ namespace test_generalized_constexpr
+ {
+
+ template < typename CharT >
+ constexpr unsigned long
+ strlen_c(const CharT *const s) noexcept
+ {
+ auto length = 0UL;
+ for (auto p = s; *p; ++p)
+ ++length;
+ return length;
+ }
+
+ static_assert(strlen_c("") == 0UL, "");
+ static_assert(strlen_c("x") == 1UL, "");
+ static_assert(strlen_c("test") == 4UL, "");
+ static_assert(strlen_c("another\0test") == 7UL, "");
+
+ }
+
+ namespace test_lambda_init_capture
+ {
+
+ int
+ test()
+ {
+ auto x = 0;
+ const auto lambda1 = [a = x](int b){ return a + b; };
+ const auto lambda2 = [a = lambda1(x)](){ return a; };
+ return lambda2();
+ }
+
+ }
+
+ namespace test_digit_separators
+ {
+
+ constexpr auto ten_million = 100'000'000;
+ static_assert(ten_million == 100000000, "");
+
+ }
+
+ namespace test_return_type_deduction
+ {
+
+ auto f(int& x) { return x; }
+ decltype(auto) g(int& x) { return x; }
+
+ template < typename T1, typename T2 >
+ struct is_same
+ {
+ static constexpr auto value = false;
+ };
+
+ template < typename T >
+ struct is_same<T, T>
+ {
+ static constexpr auto value = true;
+ };
+
+ int
+ test()
+ {
+ auto x = 0;
+ static_assert(is_same<int, decltype(f(x))>::value, "");
+ static_assert(is_same<int&, decltype(g(x))>::value, "");
+ return x;
+ }
+
+ }
+
+} // namespace cxx14
+
+#endif // __cplusplus >= 201402L
+
+]])
+
+
+dnl Tests for new features in C++17
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[
+
+// If the compiler admits that it is not ready for C++17, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201703L
+
+#error "This is not a C++17 compiler"
+
+#else
+
+#include <initializer_list>
+#include <utility>
+#include <type_traits>
+
+namespace cxx17
+{
+
+ namespace test_constexpr_lambdas
+ {
+
+ constexpr int foo = [](){return 42;}();
+
+ }
+
+ namespace test::nested_namespace::definitions
+ {
+
+ }
+
+ namespace test_fold_expression
+ {
+
+ template<typename... Args>
+ int multiply(Args... args)
+ {
+ return (args * ... * 1);
+ }
+
+ template<typename... Args>
+ bool all(Args... args)
+ {
+ return (args && ...);
+ }
+
+ }
+
+ namespace test_extended_static_assert
+ {
+
+ static_assert (true);
+
+ }
+
+ namespace test_auto_brace_init_list
+ {
+
+ auto foo = {5};
+ auto bar {5};
+
+ static_assert(std::is_same<std::initializer_list<int>, decltype(foo)>::value);
+ static_assert(std::is_same<int, decltype(bar)>::value);
+ }
+
+ namespace test_typename_in_template_template_parameter
+ {
+
+ template<template<typename> typename X> struct D;
+
+ }
+
+ namespace test_fallthrough_nodiscard_maybe_unused_attributes
+ {
+
+ int f1()
+ {
+ return 42;
+ }
+
+ [[nodiscard]] int f2()
+ {
+ [[maybe_unused]] auto unused = f1();
+
+ switch (f1())
+ {
+ case 17:
+ f1();
+ [[fallthrough]];
+ case 42:
+ f1();
+ }
+ return f1();
+ }
+
+ }
+
+ namespace test_extended_aggregate_initialization
+ {
+
+ struct base1
+ {
+ int b1, b2 = 42;
+ };
+
+ struct base2
+ {
+ base2() {
+ b3 = 42;
+ }
+ int b3;
+ };
+
+ struct derived : base1, base2
+ {
+ int d;
+ };
+
+ derived d1 {{1, 2}, {}, 4}; // full initialization
+ derived d2 {{}, {}, 4}; // value-initialized bases
+
+ }
+
+ namespace test_general_range_based_for_loop
+ {
+
+ struct iter
+ {
+ int i;
+
+ int& operator* ()
+ {
+ return i;
+ }
+
+ const int& operator* () const
+ {
+ return i;
+ }
+
+ iter& operator++()
+ {
+ ++i;
+ return *this;
+ }
+ };
+
+ struct sentinel
+ {
+ int i;
+ };
+
+ bool operator== (const iter& i, const sentinel& s)
+ {
+ return i.i == s.i;
+ }
+
+ bool operator!= (const iter& i, const sentinel& s)
+ {
+ return !(i == s);
+ }
+
+ struct range
+ {
+ iter begin() const
+ {
+ return {0};
+ }
+
+ sentinel end() const
+ {
+ return {5};
+ }
+ };
+
+ void f()
+ {
+ range r {};
+
+ for (auto i : r)
+ {
+ [[maybe_unused]] auto v = i;
+ }
+ }
+
+ }
+
+ namespace test_lambda_capture_asterisk_this_by_value
+ {
+
+ struct t
+ {
+ int i;
+ int foo()
+ {
+ return [*this]()
+ {
+ return i;
+ }();
+ }
+ };
+
+ }
+
+ namespace test_enum_class_construction
+ {
+
+ enum class byte : unsigned char
+ {};
+
+ byte foo {42};
+
+ }
+
+ namespace test_constexpr_if
+ {
+
+ template <bool cond>
+ int f ()
+ {
+ if constexpr(cond)
+ {
+ return 13;
+ }
+ else
+ {
+ return 42;
+ }
+ }
+
+ }
+
+ namespace test_selection_statement_with_initializer
+ {
+
+ int f()
+ {
+ return 13;
+ }
+
+ int f2()
+ {
+ if (auto i = f(); i > 0)
+ {
+ return 3;
+ }
+
+ switch (auto i = f(); i + 4)
+ {
+ case 17:
+ return 2;
+
+ default:
+ return 1;
+ }
+ }
+
+ }
+
+ namespace test_template_argument_deduction_for_class_templates
+ {
+
+ template <typename T1, typename T2>
+ struct pair
+ {
+ pair (T1 p1, T2 p2)
+ : m1 {p1},
+ m2 {p2}
+ {}
+
+ T1 m1;
+ T2 m2;
+ };
+
+ void f()
+ {
+ [[maybe_unused]] auto p = pair{13, 42u};
+ }
+
+ }
+
+ namespace test_non_type_auto_template_parameters
+ {
+
+ template <auto n>
+ struct B
+ {};
+
+ B<5> b1;
+ B<'a'> b2;
+
+ }
+
+ namespace test_structured_bindings
+ {
+
+ int arr[2] = { 1, 2 };
+ std::pair<int, int> pr = { 1, 2 };
+
+ auto f1() -> int(&)[2]
+ {
+ return arr;
+ }
+
+ auto f2() -> std::pair<int, int>&
+ {
+ return pr;
+ }
+
+ struct S
+ {
+ int x1 : 2;
+ volatile double y1;
+ };
+
+ S f3()
+ {
+ return {};
+ }
+
+ auto [ x1, y1 ] = f1();
+ auto& [ xr1, yr1 ] = f1();
+ auto [ x2, y2 ] = f2();
+ auto& [ xr2, yr2 ] = f2();
+ const auto [ x3, y3 ] = f3();
+
+ }
+
+ namespace test_exception_spec_type_system
+ {
+
+ struct Good {};
+ struct Bad {};
+
+ void g1() noexcept;
+ void g2();
+
+ template<typename T>
+ Bad
+ f(T*, T*);
+
+ template<typename T1, typename T2>
+ Good
+ f(T1*, T2*);
+
+ static_assert (std::is_same_v<Good, decltype(f(g1, g2))>);
+
+ }
+
+ namespace test_inline_variables
+ {
+
+ template<class T> void f(T)
+ {}
+
+ template<class T> inline T g(T)
+ {
+ return T{};
+ }
+
+ template<> inline void f<>(int)
+ {}
+
+ template<> int g<>(int)
+ {
+ return 5;
+ }
+
+ }
+
+} // namespace cxx17
+
+#endif // __cplusplus < 201703L
+
+]])
diff --git a/configure.ac b/configure.ac
index c78d9cbea62..a67801371a4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1462,10 +1462,10 @@ case "$have_compiler:$host:$target:$enable_bootstrap" in
;;
esac
-# When bootstrapping with GCC, build stage 1 in C++98 mode to ensure that a
-# C++98 compiler can still start the bootstrap.
+# When bootstrapping with GCC, build stage 1 in C++11 mode to ensure that a
+# C++11 compiler can still start the bootstrap.
if test "$enable_bootstrap:$GXX" = "yes:yes"; then
- CXX="$CXX -std=gnu++98"
+ CXX="$CXX -std=c++11"
fi
# Used for setting $lt_cv_objdir
diff --git a/gcc/aclocal.m4 b/gcc/aclocal.m4
index 1737d59d1cb..e93c1535063 100644
--- a/gcc/aclocal.m4
+++ b/gcc/aclocal.m4
@@ -18,6 +18,7 @@ m4_include([../ltsugar.m4])
m4_include([../ltversion.m4])
m4_include([../lt~obsolete.m4])
m4_include([../config/acx.m4])
+m4_include([../config/ax_cxx_compile_stdcxx.m4])
m4_include([../config/cet.m4])
m4_include([../config/codeset.m4])
m4_include([../config/depstand.m4])
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 953b464cedf..60d83c30771 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -385,6 +385,9 @@ AC_SUBST(PICFLAG_FOR_TARGET)
# -------------------------
AC_USE_SYSTEM_EXTENSIONS
+
+AX_CXX_COMPILE_STDCXX(11)
+
AC_PROG_CPP
AC_C_INLINE
diff --git a/ChangeLog b/ChangeLog
index a7fcf77b9b2..53d13eb6182 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2020-05-15 Jason Merrill <ja...@redhat.com>
+
+ * configure.ac: Update bootstrap dialect to -std=c++11.
+
2020-04-29 Thomas Schwinge <tho...@codesourcery.com>
PR target/92713
diff --git a/config/ChangeLog b/config/ChangeLog
index a4d54749669..ec09e85a84b 100644
--- a/config/ChangeLog
+++ b/config/ChangeLog
@@ -1,3 +1,8 @@
+2020-05-15 Jason Merrill <ja...@redhat.com>
+
+ * ax_cxx_compile_stdcxx.m4: Import from autoconf archive with
+ an adjustment to try the default mode.
+
2020-05-15 H.J. Lu <hongjiu...@intel.com>
PR bootstrap/95147
diff --git a/configure b/configure
index 4cc938ebb7d..3af6a530b9a 100755
--- a/configure
+++ b/configure
@@ -5523,10 +5523,10 @@ $as_echo "$as_me: WARNING: trying to bootstrap a cross compiler" >&2;}
;;
esac
-# When bootstrapping with GCC, build stage 1 in C++98 mode to ensure that a
-# C++98 compiler can still start the bootstrap.
+# When bootstrapping with GCC, build stage 1 in C++11 mode to ensure that a
+# C++11 compiler can still start the bootstrap.
if test "$enable_bootstrap:$GXX" = "yes:yes"; then
- CXX="$CXX -std=gnu++98"
+ CXX="$CXX -std=c++11"
fi
# Used for setting $lt_cv_objdir
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3ae73f21560..9743ff65add 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2020-05-15 Jason Merrill <ja...@redhat.com>
+
+ * aclocal.m4: Add ax_cxx_compile_stdcxx.m4.
+ * configure.ac: Use AX_CXX_COMPILE_STDCXX(11).
+
+2020-05-14 Jason Merrill <ja...@redhat.com>
+
+ * doc/install.texi (Prerequisites): Update boostrap compiler
+ requirement to C++11/GCC 4.8.
+
2020-05-15 Segher Boessenkool <seg...@kernel.crashing.org>
* config/rs6000/rs6000-builtin.def (BU_FUTURE_MISC_2): Also require
diff --git a/gcc/configure b/gcc/configure
index 8f0f67494fe..4531d50eb0f 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -847,6 +847,7 @@ c_loose_warn
loose_warn
aliasing_flags
CPP
+HAVE_CXX11
EGREP
GREP
CXXCPP
@@ -5708,6 +5709,999 @@ $as_echo "$ac_cv_safe_to_define___extensions__" >&6; }
$as_echo "#define _TANDEM_SOURCE 1" >>confdefs.h
+
+ ax_cxx_compile_alternatives="11 0x" ax_cxx_compile_cxx11_required=true
+ ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+ ac_success=no
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX supports C++11 features by default" >&5
+$as_echo_n "checking whether $CXX supports C++11 features by default... " >&6; }
+if ${ax_cv_cxx_compile_cxx11+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+
+// If the compiler admits that it is not ready for C++11, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201103L
+
+#error "This is not a C++11 compiler"
+
+#else
+
+namespace cxx11
+{
+
+ namespace test_static_assert
+ {
+
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ }
+
+ namespace test_final_override
+ {
+
+ struct Base
+ {
+ virtual ~Base() {}
+ virtual void f() {}
+ };
+
+ struct Derived : public Base
+ {
+ virtual ~Derived() override {}
+ virtual void f() override {}
+ };
+
+ }
+
+ namespace test_double_right_angle_brackets
+ {
+
+ template < typename T >
+ struct check {};
+
+ typedef check<void> single_type;
+ typedef check<check<void>> double_type;
+ typedef check<check<check<void>>> triple_type;
+ typedef check<check<check<check<void>>>> quadruple_type;
+
+ }
+
+ namespace test_decltype
+ {
+
+ int
+ f()
+ {
+ int a = 1;
+ decltype(a) b = 2;
+ return a + b;
+ }
+
+ }
+
+ namespace test_type_deduction
+ {
+
+ template < typename T1, typename T2 >
+ struct is_same
+ {
+ static const bool value = false;
+ };
+
+ template < typename T >
+ struct is_same<T, T>
+ {
+ static const bool value = true;
+ };
+
+ template < typename T1, typename T2 >
+ auto
+ add(T1 a1, T2 a2) -> decltype(a1 + a2)
+ {
+ return a1 + a2;
+ }
+
+ int
+ test(const int c, volatile int v)
+ {
+ static_assert(is_same<int, decltype(0)>::value == true, "");
+ static_assert(is_same<int, decltype(c)>::value == false, "");
+ static_assert(is_same<int, decltype(v)>::value == false, "");
+ auto ac = c;
+ auto av = v;
+ auto sumi = ac + av + 'x';
+ auto sumf = ac + av + 1.0;
+ static_assert(is_same<int, decltype(ac)>::value == true, "");
+ static_assert(is_same<int, decltype(av)>::value == true, "");
+ static_assert(is_same<int, decltype(sumi)>::value == true, "");
+ static_assert(is_same<int, decltype(sumf)>::value == false, "");
+ static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
+ return (sumf > 0.0) ? sumi : add(c, v);
+ }
+
+ }
+
+ namespace test_noexcept
+ {
+
+ int f() { return 0; }
+ int g() noexcept { return 0; }
+
+ static_assert(noexcept(f()) == false, "");
+ static_assert(noexcept(g()) == true, "");
+
+ }
+
+ namespace test_constexpr
+ {
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
+ {
+ return *s ? strlen_c_r(s + 1, acc + 1) : acc;
+ }
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c(const CharT *const s) noexcept
+ {
+ return strlen_c_r(s, 0UL);
+ }
+
+ static_assert(strlen_c("") == 0UL, "");
+ static_assert(strlen_c("1") == 1UL, "");
+ static_assert(strlen_c("example") == 7UL, "");
+ static_assert(strlen_c("another\0example") == 7UL, "");
+
+ }
+
+ namespace test_rvalue_references
+ {
+
+ template < int N >
+ struct answer
+ {
+ static constexpr int value = N;
+ };
+
+ answer<1> f(int&) { return answer<1>(); }
+ answer<2> f(const int&) { return answer<2>(); }
+ answer<3> f(int&&) { return answer<3>(); }
+
+ void
+ test()
+ {
+ int i = 0;
+ const int c = 0;
+ static_assert(decltype(f(i))::value == 1, "");
+ static_assert(decltype(f(c))::value == 2, "");
+ static_assert(decltype(f(0))::value == 3, "");
+ }
+
+ }
+
+ namespace test_uniform_initialization
+ {
+
+ struct test
+ {
+ static const int zero {};
+ static const int one {1};
+ };
+
+ static_assert(test::zero == 0, "");
+ static_assert(test::one == 1, "");
+
+ }
+
+ namespace test_lambdas
+ {
+
+ void
+ test1()
+ {
+ auto lambda1 = [](){};
+ auto lambda2 = lambda1;
+ lambda1();
+ lambda2();
+ }
+
+ int
+ test2()
+ {
+ auto a = [](int i, int j){ return i + j; }(1, 2);
+ auto b = []() -> int { return '0'; }();
+ auto c = [=](){ return a + b; }();
+ auto d = [&](){ return c; }();
+ auto e = [a, &b](int x) mutable {
+ const auto identity = [](int y){ return y; };
+ for (auto i = 0; i < a; ++i)
+ a += b--;
+ return x + identity(a + b);
+ }(0);
+ return a + b + c + d + e;
+ }
+
+ int
+ test3()
+ {
+ const auto nullary = [](){ return 0; };
+ const auto unary = [](int x){ return x; };
+ using nullary_t = decltype(nullary);
+ using unary_t = decltype(unary);
+ const auto higher1st = [](nullary_t f){ return f(); };
+ const auto higher2nd = [unary](nullary_t f1){
+ return [unary, f1](unary_t f2){ return f2(unary(f1())); };
+ };
+ return higher1st(nullary) + higher2nd(nullary)(unary);
+ }
+
+ }
+
+ namespace test_variadic_templates
+ {
+
+ template <int...>
+ struct sum;
+
+ template <int N0, int... N1toN>
+ struct sum<N0, N1toN...>
+ {
+ static constexpr auto value = N0 + sum<N1toN...>::value;
+ };
+
+ template <>
+ struct sum<>
+ {
+ static constexpr auto value = 0;
+ };
+
+ static_assert(sum<>::value == 0, "");
+ static_assert(sum<1>::value == 1, "");
+ static_assert(sum<23>::value == 23, "");
+ static_assert(sum<1, 2>::value == 3, "");
+ static_assert(sum<5, 5, 11>::value == 21, "");
+ static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
+
+ }
+
+ // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+ // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
+ // because of this.
+ namespace test_template_alias_sfinae
+ {
+
+ struct foo {};
+
+ template<typename T>
+ using member = typename T::member_type;
+
+ template<typename T>
+ void func(...) {}
+
+ template<typename T>
+ void func(member<T>*) {}
+
+ void test();
+
+ void test() { func<foo>(0); }
+
+ }
+
+} // namespace cxx11
+
+#endif // __cplusplus >= 201103L
+
+
+
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+ ax_cv_cxx_compile_cxx11=yes
+else
+ ax_cv_cxx_compile_cxx11=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_cxx_compile_cxx11" >&5
+$as_echo "$ax_cv_cxx_compile_cxx11" >&6; }
+ if test x$ax_cv_cxx_compile_cxx11 = xyes; then
+ ac_success=yes
+ fi
+
+ if test x$ac_success = xno; then
+ for alternative in ${ax_cxx_compile_alternatives}; do
+ switch="-std=gnu++${alternative}"
+ cachevar=`$as_echo "ax_cv_cxx_compile_cxx11_$switch" | $as_tr_sh`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX supports C++11 features with $switch" >&5
+$as_echo_n "checking whether $CXX supports C++11 features with $switch... " >&6; }
+if eval \${$cachevar+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_save_CXX="$CXX"
+ CXX="$CXX $switch"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+
+// If the compiler admits that it is not ready for C++11, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201103L
+
+#error "This is not a C++11 compiler"
+
+#else
+
+namespace cxx11
+{
+
+ namespace test_static_assert
+ {
+
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ }
+
+ namespace test_final_override
+ {
+
+ struct Base
+ {
+ virtual ~Base() {}
+ virtual void f() {}
+ };
+
+ struct Derived : public Base
+ {
+ virtual ~Derived() override {}
+ virtual void f() override {}
+ };
+
+ }
+
+ namespace test_double_right_angle_brackets
+ {
+
+ template < typename T >
+ struct check {};
+
+ typedef check<void> single_type;
+ typedef check<check<void>> double_type;
+ typedef check<check<check<void>>> triple_type;
+ typedef check<check<check<check<void>>>> quadruple_type;
+
+ }
+
+ namespace test_decltype
+ {
+
+ int
+ f()
+ {
+ int a = 1;
+ decltype(a) b = 2;
+ return a + b;
+ }
+
+ }
+
+ namespace test_type_deduction
+ {
+
+ template < typename T1, typename T2 >
+ struct is_same
+ {
+ static const bool value = false;
+ };
+
+ template < typename T >
+ struct is_same<T, T>
+ {
+ static const bool value = true;
+ };
+
+ template < typename T1, typename T2 >
+ auto
+ add(T1 a1, T2 a2) -> decltype(a1 + a2)
+ {
+ return a1 + a2;
+ }
+
+ int
+ test(const int c, volatile int v)
+ {
+ static_assert(is_same<int, decltype(0)>::value == true, "");
+ static_assert(is_same<int, decltype(c)>::value == false, "");
+ static_assert(is_same<int, decltype(v)>::value == false, "");
+ auto ac = c;
+ auto av = v;
+ auto sumi = ac + av + 'x';
+ auto sumf = ac + av + 1.0;
+ static_assert(is_same<int, decltype(ac)>::value == true, "");
+ static_assert(is_same<int, decltype(av)>::value == true, "");
+ static_assert(is_same<int, decltype(sumi)>::value == true, "");
+ static_assert(is_same<int, decltype(sumf)>::value == false, "");
+ static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
+ return (sumf > 0.0) ? sumi : add(c, v);
+ }
+
+ }
+
+ namespace test_noexcept
+ {
+
+ int f() { return 0; }
+ int g() noexcept { return 0; }
+
+ static_assert(noexcept(f()) == false, "");
+ static_assert(noexcept(g()) == true, "");
+
+ }
+
+ namespace test_constexpr
+ {
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
+ {
+ return *s ? strlen_c_r(s + 1, acc + 1) : acc;
+ }
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c(const CharT *const s) noexcept
+ {
+ return strlen_c_r(s, 0UL);
+ }
+
+ static_assert(strlen_c("") == 0UL, "");
+ static_assert(strlen_c("1") == 1UL, "");
+ static_assert(strlen_c("example") == 7UL, "");
+ static_assert(strlen_c("another\0example") == 7UL, "");
+
+ }
+
+ namespace test_rvalue_references
+ {
+
+ template < int N >
+ struct answer
+ {
+ static constexpr int value = N;
+ };
+
+ answer<1> f(int&) { return answer<1>(); }
+ answer<2> f(const int&) { return answer<2>(); }
+ answer<3> f(int&&) { return answer<3>(); }
+
+ void
+ test()
+ {
+ int i = 0;
+ const int c = 0;
+ static_assert(decltype(f(i))::value == 1, "");
+ static_assert(decltype(f(c))::value == 2, "");
+ static_assert(decltype(f(0))::value == 3, "");
+ }
+
+ }
+
+ namespace test_uniform_initialization
+ {
+
+ struct test
+ {
+ static const int zero {};
+ static const int one {1};
+ };
+
+ static_assert(test::zero == 0, "");
+ static_assert(test::one == 1, "");
+
+ }
+
+ namespace test_lambdas
+ {
+
+ void
+ test1()
+ {
+ auto lambda1 = [](){};
+ auto lambda2 = lambda1;
+ lambda1();
+ lambda2();
+ }
+
+ int
+ test2()
+ {
+ auto a = [](int i, int j){ return i + j; }(1, 2);
+ auto b = []() -> int { return '0'; }();
+ auto c = [=](){ return a + b; }();
+ auto d = [&](){ return c; }();
+ auto e = [a, &b](int x) mutable {
+ const auto identity = [](int y){ return y; };
+ for (auto i = 0; i < a; ++i)
+ a += b--;
+ return x + identity(a + b);
+ }(0);
+ return a + b + c + d + e;
+ }
+
+ int
+ test3()
+ {
+ const auto nullary = [](){ return 0; };
+ const auto unary = [](int x){ return x; };
+ using nullary_t = decltype(nullary);
+ using unary_t = decltype(unary);
+ const auto higher1st = [](nullary_t f){ return f(); };
+ const auto higher2nd = [unary](nullary_t f1){
+ return [unary, f1](unary_t f2){ return f2(unary(f1())); };
+ };
+ return higher1st(nullary) + higher2nd(nullary)(unary);
+ }
+
+ }
+
+ namespace test_variadic_templates
+ {
+
+ template <int...>
+ struct sum;
+
+ template <int N0, int... N1toN>
+ struct sum<N0, N1toN...>
+ {
+ static constexpr auto value = N0 + sum<N1toN...>::value;
+ };
+
+ template <>
+ struct sum<>
+ {
+ static constexpr auto value = 0;
+ };
+
+ static_assert(sum<>::value == 0, "");
+ static_assert(sum<1>::value == 1, "");
+ static_assert(sum<23>::value == 23, "");
+ static_assert(sum<1, 2>::value == 3, "");
+ static_assert(sum<5, 5, 11>::value == 21, "");
+ static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
+
+ }
+
+ // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+ // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
+ // because of this.
+ namespace test_template_alias_sfinae
+ {
+
+ struct foo {};
+
+ template<typename T>
+ using member = typename T::member_type;
+
+ template<typename T>
+ void func(...) {}
+
+ template<typename T>
+ void func(member<T>*) {}
+
+ void test();
+
+ void test() { func<foo>(0); }
+
+ }
+
+} // namespace cxx11
+
+#endif // __cplusplus >= 201103L
+
+
+
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+ eval $cachevar=yes
+else
+ eval $cachevar=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ CXX="$ac_save_CXX"
+fi
+eval ac_res=\$$cachevar
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+ if eval test x\$$cachevar = xyes; then
+ CXX="$CXX $switch"
+ if test -n "$CXXCPP" ; then
+ CXXCPP="$CXXCPP $switch"
+ fi
+ ac_success=yes
+ break
+ fi
+ done
+ fi
+
+ if test x$ac_success = xno; then
+ for alternative in ${ax_cxx_compile_alternatives}; do
+ for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; do
+ cachevar=`$as_echo "ax_cv_cxx_compile_cxx11_$switch" | $as_tr_sh`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX supports C++11 features with $switch" >&5
+$as_echo_n "checking whether $CXX supports C++11 features with $switch... " >&6; }
+if eval \${$cachevar+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ ac_save_CXX="$CXX"
+ CXX="$CXX $switch"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+
+// If the compiler admits that it is not ready for C++11, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201103L
+
+#error "This is not a C++11 compiler"
+
+#else
+
+namespace cxx11
+{
+
+ namespace test_static_assert
+ {
+
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ }
+
+ namespace test_final_override
+ {
+
+ struct Base
+ {
+ virtual ~Base() {}
+ virtual void f() {}
+ };
+
+ struct Derived : public Base
+ {
+ virtual ~Derived() override {}
+ virtual void f() override {}
+ };
+
+ }
+
+ namespace test_double_right_angle_brackets
+ {
+
+ template < typename T >
+ struct check {};
+
+ typedef check<void> single_type;
+ typedef check<check<void>> double_type;
+ typedef check<check<check<void>>> triple_type;
+ typedef check<check<check<check<void>>>> quadruple_type;
+
+ }
+
+ namespace test_decltype
+ {
+
+ int
+ f()
+ {
+ int a = 1;
+ decltype(a) b = 2;
+ return a + b;
+ }
+
+ }
+
+ namespace test_type_deduction
+ {
+
+ template < typename T1, typename T2 >
+ struct is_same
+ {
+ static const bool value = false;
+ };
+
+ template < typename T >
+ struct is_same<T, T>
+ {
+ static const bool value = true;
+ };
+
+ template < typename T1, typename T2 >
+ auto
+ add(T1 a1, T2 a2) -> decltype(a1 + a2)
+ {
+ return a1 + a2;
+ }
+
+ int
+ test(const int c, volatile int v)
+ {
+ static_assert(is_same<int, decltype(0)>::value == true, "");
+ static_assert(is_same<int, decltype(c)>::value == false, "");
+ static_assert(is_same<int, decltype(v)>::value == false, "");
+ auto ac = c;
+ auto av = v;
+ auto sumi = ac + av + 'x';
+ auto sumf = ac + av + 1.0;
+ static_assert(is_same<int, decltype(ac)>::value == true, "");
+ static_assert(is_same<int, decltype(av)>::value == true, "");
+ static_assert(is_same<int, decltype(sumi)>::value == true, "");
+ static_assert(is_same<int, decltype(sumf)>::value == false, "");
+ static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
+ return (sumf > 0.0) ? sumi : add(c, v);
+ }
+
+ }
+
+ namespace test_noexcept
+ {
+
+ int f() { return 0; }
+ int g() noexcept { return 0; }
+
+ static_assert(noexcept(f()) == false, "");
+ static_assert(noexcept(g()) == true, "");
+
+ }
+
+ namespace test_constexpr
+ {
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
+ {
+ return *s ? strlen_c_r(s + 1, acc + 1) : acc;
+ }
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c(const CharT *const s) noexcept
+ {
+ return strlen_c_r(s, 0UL);
+ }
+
+ static_assert(strlen_c("") == 0UL, "");
+ static_assert(strlen_c("1") == 1UL, "");
+ static_assert(strlen_c("example") == 7UL, "");
+ static_assert(strlen_c("another\0example") == 7UL, "");
+
+ }
+
+ namespace test_rvalue_references
+ {
+
+ template < int N >
+ struct answer
+ {
+ static constexpr int value = N;
+ };
+
+ answer<1> f(int&) { return answer<1>(); }
+ answer<2> f(const int&) { return answer<2>(); }
+ answer<3> f(int&&) { return answer<3>(); }
+
+ void
+ test()
+ {
+ int i = 0;
+ const int c = 0;
+ static_assert(decltype(f(i))::value == 1, "");
+ static_assert(decltype(f(c))::value == 2, "");
+ static_assert(decltype(f(0))::value == 3, "");
+ }
+
+ }
+
+ namespace test_uniform_initialization
+ {
+
+ struct test
+ {
+ static const int zero {};
+ static const int one {1};
+ };
+
+ static_assert(test::zero == 0, "");
+ static_assert(test::one == 1, "");
+
+ }
+
+ namespace test_lambdas
+ {
+
+ void
+ test1()
+ {
+ auto lambda1 = [](){};
+ auto lambda2 = lambda1;
+ lambda1();
+ lambda2();
+ }
+
+ int
+ test2()
+ {
+ auto a = [](int i, int j){ return i + j; }(1, 2);
+ auto b = []() -> int { return '0'; }();
+ auto c = [=](){ return a + b; }();
+ auto d = [&](){ return c; }();
+ auto e = [a, &b](int x) mutable {
+ const auto identity = [](int y){ return y; };
+ for (auto i = 0; i < a; ++i)
+ a += b--;
+ return x + identity(a + b);
+ }(0);
+ return a + b + c + d + e;
+ }
+
+ int
+ test3()
+ {
+ const auto nullary = [](){ return 0; };
+ const auto unary = [](int x){ return x; };
+ using nullary_t = decltype(nullary);
+ using unary_t = decltype(unary);
+ const auto higher1st = [](nullary_t f){ return f(); };
+ const auto higher2nd = [unary](nullary_t f1){
+ return [unary, f1](unary_t f2){ return f2(unary(f1())); };
+ };
+ return higher1st(nullary) + higher2nd(nullary)(unary);
+ }
+
+ }
+
+ namespace test_variadic_templates
+ {
+
+ template <int...>
+ struct sum;
+
+ template <int N0, int... N1toN>
+ struct sum<N0, N1toN...>
+ {
+ static constexpr auto value = N0 + sum<N1toN...>::value;
+ };
+
+ template <>
+ struct sum<>
+ {
+ static constexpr auto value = 0;
+ };
+
+ static_assert(sum<>::value == 0, "");
+ static_assert(sum<1>::value == 1, "");
+ static_assert(sum<23>::value == 23, "");
+ static_assert(sum<1, 2>::value == 3, "");
+ static_assert(sum<5, 5, 11>::value == 21, "");
+ static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
+
+ }
+
+ // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+ // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
+ // because of this.
+ namespace test_template_alias_sfinae
+ {
+
+ struct foo {};
+
+ template<typename T>
+ using member = typename T::member_type;
+
+ template<typename T>
+ void func(...) {}
+
+ template<typename T>
+ void func(member<T>*) {}
+
+ void test();
+
+ void test() { func<foo>(0); }
+
+ }
+
+} // namespace cxx11
+
+#endif // __cplusplus >= 201103L
+
+
+
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+ eval $cachevar=yes
+else
+ eval $cachevar=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ CXX="$ac_save_CXX"
+fi
+eval ac_res=\$$cachevar
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+ if eval test x\$$cachevar = xyes; then
+ CXX="$CXX $switch"
+ if test -n "$CXXCPP" ; then
+ CXXCPP="$CXXCPP $switch"
+ fi
+ ac_success=yes
+ break
+ fi
+ done
+ if test x$ac_success = xyes; then
+ break
+ fi
+ done
+ fi
+ ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+
+ if test x$ax_cxx_compile_cxx11_required = xtrue; then
+ if test x$ac_success = xno; then
+ as_fn_error $? "*** A compiler with support for C++11 language features is required." "$LINENO" 5
+ fi
+ fi
+ if test x$ac_success = xno; then
+ HAVE_CXX11=0
+ { $as_echo "$as_me:${as_lineno-$LINENO}: No compiler with C++11 support was found" >&5
+$as_echo "$as_me: No compiler with C++11 support was found" >&6;}
+ else
+ HAVE_CXX11=1
+
+$as_echo "#define HAVE_CXX11 1" >>confdefs.h
+
+ fi
+
+
+
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
@@ -19018,7 +20012,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 19021 "configure"
+#line 20015 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -19124,7 +20118,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 19127 "configure"
+#line 20121 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
