| 1 | # Copyright (c) 2016-2017 Free Software Foundation, Inc. |
| 2 | # |
| 3 | # Originally based on the AX_CXX_COMPILE_STDCXX macro found at the url |
| 4 | # below. |
| 5 | # |
| 6 | # Local GDB customizations: |
| 7 | # |
| 8 | # - AC_SUBST CXX_DIALECT instead of changing CXX/CXXCPP. |
| 9 | # |
| 10 | # =========================================================================== |
| 11 | # http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html |
| 12 | # =========================================================================== |
| 13 | # |
| 14 | # SYNOPSIS |
| 15 | # |
| 16 | # AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional]) |
| 17 | # |
| 18 | # DESCRIPTION |
| 19 | # |
| 20 | # Check for baseline language coverage in the compiler for the specified |
| 21 | # version of the C++ standard. If necessary, add switches to CXX and |
| 22 | # CXXCPP to enable support. VERSION may be '11' (for the C++11 standard) |
| 23 | # or '14' (for the C++14 standard). |
| 24 | # |
| 25 | # The second argument, if specified, indicates whether you insist on an |
| 26 | # extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. |
| 27 | # -std=c++11). If neither is specified, you get whatever works, with |
| 28 | # preference for an extended mode. |
| 29 | # |
| 30 | # The third argument, if specified 'mandatory' or if left unspecified, |
| 31 | # indicates that baseline support for the specified C++ standard is |
| 32 | # required and that the macro should error out if no mode with that |
| 33 | # support is found. If specified 'optional', then configuration proceeds |
| 34 | # regardless, after defining HAVE_CXX${VERSION} if and only if a |
| 35 | # supporting mode is found. |
| 36 | # |
| 37 | # LICENSE |
| 38 | # |
| 39 | # Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com> |
| 40 | # Copyright (c) 2012 Zack Weinberg <zackw@panix.com> |
| 41 | # Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu> |
| 42 | # Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com> |
| 43 | # Copyright (c) 2015 Paul Norman <penorman@mac.com> |
| 44 | # Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu> |
| 45 | # |
| 46 | # Copying and distribution of this file, with or without modification, are |
| 47 | # permitted in any medium without royalty provided the copyright notice |
| 48 | # and this notice are preserved. This file is offered as-is, without any |
| 49 | # warranty. |
| 50 | |
| 51 | #serial 4 |
| 52 | |
| 53 | dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro |
| 54 | dnl (serial version number 13). |
| 55 | |
| 56 | AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl |
| 57 | m4_if([$1], [11], [], |
| 58 | [$1], [14], [], |
| 59 | [$1], [17], [m4_fatal([support for C++17 not yet implemented in AX_CXX_COMPILE_STDCXX])], |
| 60 | [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl |
| 61 | m4_if([$2], [], [], |
| 62 | [$2], [ext], [], |
| 63 | [$2], [noext], [], |
| 64 | [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl |
| 65 | m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true], |
| 66 | [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true], |
| 67 | [$3], [optional], [ax_cxx_compile_cxx$1_required=false], |
| 68 | [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])]) |
| 69 | AC_LANG_PUSH([C++])dnl |
| 70 | CXX_DIALECT="" |
| 71 | ac_success=no |
| 72 | AC_CACHE_CHECK(whether $CXX supports C++$1 features by default, |
| 73 | ax_cv_cxx_compile_cxx$1, |
| 74 | [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], |
| 75 | [ax_cv_cxx_compile_cxx$1=yes], |
| 76 | [ax_cv_cxx_compile_cxx$1=no])]) |
| 77 | if test x$ax_cv_cxx_compile_cxx$1 = xyes; then |
| 78 | ac_success=yes |
| 79 | fi |
| 80 | |
| 81 | m4_if([$2], [noext], [], [dnl |
| 82 | if test x$ac_success = xno; then |
| 83 | for switch in -std=gnu++$1 -std=gnu++0x; do |
| 84 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) |
| 85 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, |
| 86 | $cachevar, |
| 87 | [ac_save_CXX="$CXX" |
| 88 | CXX="$CXX $switch" |
| 89 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], |
| 90 | [eval $cachevar=yes], |
| 91 | [eval $cachevar=no]) |
| 92 | CXX="$ac_save_CXX"]) |
| 93 | if eval test x\$$cachevar = xyes; then |
| 94 | CXX_DIALECT="$switch" |
| 95 | ac_success=yes |
| 96 | break |
| 97 | fi |
| 98 | done |
| 99 | fi]) |
| 100 | |
| 101 | m4_if([$2], [ext], [], [dnl |
| 102 | if test x$ac_success = xno; then |
| 103 | dnl HP's aCC needs +std=c++11 according to: |
| 104 | dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf |
| 105 | dnl Cray's crayCC needs "-h std=c++11" |
| 106 | for switch in -std=c++$1 -std=c++0x +std=c++$1 "-h std=c++$1"; do |
| 107 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) |
| 108 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, |
| 109 | $cachevar, |
| 110 | [ac_save_CXX="$CXX" |
| 111 | CXX="$CXX $switch" |
| 112 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], |
| 113 | [eval $cachevar=yes], |
| 114 | [eval $cachevar=no]) |
| 115 | CXX="$ac_save_CXX"]) |
| 116 | if eval test x\$$cachevar = xyes; then |
| 117 | CXX_DIALECT="$switch" |
| 118 | ac_success=yes |
| 119 | break |
| 120 | fi |
| 121 | done |
| 122 | fi]) |
| 123 | AC_LANG_POP([C++]) |
| 124 | if test x$ax_cxx_compile_cxx$1_required = xtrue; then |
| 125 | if test x$ac_success = xno; then |
| 126 | AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.]) |
| 127 | fi |
| 128 | fi |
| 129 | if test x$ac_success = xno; then |
| 130 | HAVE_CXX$1=0 |
| 131 | AC_MSG_NOTICE([No compiler with C++$1 support was found]) |
| 132 | else |
| 133 | HAVE_CXX$1=1 |
| 134 | AC_DEFINE(HAVE_CXX$1,1, |
| 135 | [define if the compiler supports basic C++$1 syntax]) |
| 136 | fi |
| 137 | AC_SUBST(HAVE_CXX$1) |
| 138 | AC_SUBST(CXX_DIALECT) |
| 139 | ]) |
| 140 | |
| 141 | |
| 142 | dnl Test body for checking C++11 support |
| 143 | |
| 144 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11], |
| 145 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 |
| 146 | ) |
| 147 | |
| 148 | |
| 149 | dnl Test body for checking C++14 support |
| 150 | |
| 151 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14], |
| 152 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 |
| 153 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 |
| 154 | ) |
| 155 | |
| 156 | |
| 157 | dnl Tests for new features in C++11 |
| 158 | |
| 159 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[ |
| 160 | |
| 161 | // If the compiler admits that it is not ready for C++11, why torture it? |
| 162 | // Hopefully, this will speed up the test. |
| 163 | |
| 164 | #ifndef __cplusplus |
| 165 | |
| 166 | #error "This is not a C++ compiler" |
| 167 | |
| 168 | #elif __cplusplus < 201103L |
| 169 | |
| 170 | #error "This is not a C++11 compiler" |
| 171 | |
| 172 | #else |
| 173 | |
| 174 | namespace cxx11 |
| 175 | { |
| 176 | |
| 177 | namespace test_static_assert |
| 178 | { |
| 179 | |
| 180 | template <typename T> |
| 181 | struct check |
| 182 | { |
| 183 | static_assert(sizeof(int) <= sizeof(T), "not big enough"); |
| 184 | }; |
| 185 | |
| 186 | } |
| 187 | |
| 188 | namespace test_final_override |
| 189 | { |
| 190 | |
| 191 | struct Base |
| 192 | { |
| 193 | virtual void f() {} |
| 194 | }; |
| 195 | |
| 196 | struct Derived : public Base |
| 197 | { |
| 198 | virtual void f() override {} |
| 199 | }; |
| 200 | |
| 201 | } |
| 202 | |
| 203 | namespace test_double_right_angle_brackets |
| 204 | { |
| 205 | |
| 206 | template < typename T > |
| 207 | struct check {}; |
| 208 | |
| 209 | typedef check<void> single_type; |
| 210 | typedef check<check<void>> double_type; |
| 211 | typedef check<check<check<void>>> triple_type; |
| 212 | typedef check<check<check<check<void>>>> quadruple_type; |
| 213 | |
| 214 | } |
| 215 | |
| 216 | namespace test_decltype |
| 217 | { |
| 218 | |
| 219 | int |
| 220 | f() |
| 221 | { |
| 222 | int a = 1; |
| 223 | decltype(a) b = 2; |
| 224 | return a + b; |
| 225 | } |
| 226 | |
| 227 | } |
| 228 | |
| 229 | namespace test_type_deduction |
| 230 | { |
| 231 | |
| 232 | template < typename T1, typename T2 > |
| 233 | struct is_same |
| 234 | { |
| 235 | static const bool value = false; |
| 236 | }; |
| 237 | |
| 238 | template < typename T > |
| 239 | struct is_same<T, T> |
| 240 | { |
| 241 | static const bool value = true; |
| 242 | }; |
| 243 | |
| 244 | template < typename T1, typename T2 > |
| 245 | auto |
| 246 | add(T1 a1, T2 a2) -> decltype(a1 + a2) |
| 247 | { |
| 248 | return a1 + a2; |
| 249 | } |
| 250 | |
| 251 | int |
| 252 | test(const int c, volatile int v) |
| 253 | { |
| 254 | static_assert(is_same<int, decltype(0)>::value == true, ""); |
| 255 | static_assert(is_same<int, decltype(c)>::value == false, ""); |
| 256 | static_assert(is_same<int, decltype(v)>::value == false, ""); |
| 257 | auto ac = c; |
| 258 | auto av = v; |
| 259 | auto sumi = ac + av + 'x'; |
| 260 | auto sumf = ac + av + 1.0; |
| 261 | static_assert(is_same<int, decltype(ac)>::value == true, ""); |
| 262 | static_assert(is_same<int, decltype(av)>::value == true, ""); |
| 263 | static_assert(is_same<int, decltype(sumi)>::value == true, ""); |
| 264 | static_assert(is_same<int, decltype(sumf)>::value == false, ""); |
| 265 | static_assert(is_same<int, decltype(add(c, v))>::value == true, ""); |
| 266 | return (sumf > 0.0) ? sumi : add(c, v); |
| 267 | } |
| 268 | |
| 269 | } |
| 270 | |
| 271 | namespace test_noexcept |
| 272 | { |
| 273 | |
| 274 | int f() { return 0; } |
| 275 | int g() noexcept { return 0; } |
| 276 | |
| 277 | static_assert(noexcept(f()) == false, ""); |
| 278 | static_assert(noexcept(g()) == true, ""); |
| 279 | |
| 280 | } |
| 281 | |
| 282 | namespace test_constexpr |
| 283 | { |
| 284 | |
| 285 | template < typename CharT > |
| 286 | unsigned long constexpr |
| 287 | strlen_c_r(const CharT *const s, const unsigned long acc) noexcept |
| 288 | { |
| 289 | return *s ? strlen_c_r(s + 1, acc + 1) : acc; |
| 290 | } |
| 291 | |
| 292 | template < typename CharT > |
| 293 | unsigned long constexpr |
| 294 | strlen_c(const CharT *const s) noexcept |
| 295 | { |
| 296 | return strlen_c_r(s, 0UL); |
| 297 | } |
| 298 | |
| 299 | static_assert(strlen_c("") == 0UL, ""); |
| 300 | static_assert(strlen_c("1") == 1UL, ""); |
| 301 | static_assert(strlen_c("example") == 7UL, ""); |
| 302 | static_assert(strlen_c("another\0example") == 7UL, ""); |
| 303 | |
| 304 | } |
| 305 | |
| 306 | namespace test_rvalue_references |
| 307 | { |
| 308 | |
| 309 | template < int N > |
| 310 | struct answer |
| 311 | { |
| 312 | static constexpr int value = N; |
| 313 | }; |
| 314 | |
| 315 | answer<1> f(int&) { return answer<1>(); } |
| 316 | answer<2> f(const int&) { return answer<2>(); } |
| 317 | answer<3> f(int&&) { return answer<3>(); } |
| 318 | |
| 319 | void |
| 320 | test() |
| 321 | { |
| 322 | int i = 0; |
| 323 | const int c = 0; |
| 324 | static_assert(decltype(f(i))::value == 1, ""); |
| 325 | static_assert(decltype(f(c))::value == 2, ""); |
| 326 | static_assert(decltype(f(0))::value == 3, ""); |
| 327 | } |
| 328 | |
| 329 | } |
| 330 | |
| 331 | namespace test_uniform_initialization |
| 332 | { |
| 333 | |
| 334 | struct test |
| 335 | { |
| 336 | static const int zero {}; |
| 337 | static const int one {1}; |
| 338 | }; |
| 339 | |
| 340 | static_assert(test::zero == 0, ""); |
| 341 | static_assert(test::one == 1, ""); |
| 342 | |
| 343 | } |
| 344 | |
| 345 | namespace test_lambdas |
| 346 | { |
| 347 | |
| 348 | void |
| 349 | test1() |
| 350 | { |
| 351 | auto lambda1 = [](){}; |
| 352 | auto lambda2 = lambda1; |
| 353 | lambda1(); |
| 354 | lambda2(); |
| 355 | } |
| 356 | |
| 357 | int |
| 358 | test2() |
| 359 | { |
| 360 | auto a = [](int i, int j){ return i + j; }(1, 2); |
| 361 | auto b = []() -> int { return '0'; }(); |
| 362 | auto c = [=](){ return a + b; }(); |
| 363 | auto d = [&](){ return c; }(); |
| 364 | auto e = [a, &b](int x) mutable { |
| 365 | const auto identity = [](int y){ return y; }; |
| 366 | for (auto i = 0; i < a; ++i) |
| 367 | a += b--; |
| 368 | return x + identity(a + b); |
| 369 | }(0); |
| 370 | return a + b + c + d + e; |
| 371 | } |
| 372 | |
| 373 | int |
| 374 | test3() |
| 375 | { |
| 376 | const auto nullary = [](){ return 0; }; |
| 377 | const auto unary = [](int x){ return x; }; |
| 378 | using nullary_t = decltype(nullary); |
| 379 | using unary_t = decltype(unary); |
| 380 | const auto higher1st = [](nullary_t f){ return f(); }; |
| 381 | const auto higher2nd = [unary](nullary_t f1){ |
| 382 | return [unary, f1](unary_t f2){ return f2(unary(f1())); }; |
| 383 | }; |
| 384 | return higher1st(nullary) + higher2nd(nullary)(unary); |
| 385 | } |
| 386 | |
| 387 | } |
| 388 | |
| 389 | namespace test_variadic_templates |
| 390 | { |
| 391 | |
| 392 | template <int...> |
| 393 | struct sum; |
| 394 | |
| 395 | template <int N0, int... N1toN> |
| 396 | struct sum<N0, N1toN...> |
| 397 | { |
| 398 | static constexpr auto value = N0 + sum<N1toN...>::value; |
| 399 | }; |
| 400 | |
| 401 | template <> |
| 402 | struct sum<> |
| 403 | { |
| 404 | static constexpr auto value = 0; |
| 405 | }; |
| 406 | |
| 407 | static_assert(sum<>::value == 0, ""); |
| 408 | static_assert(sum<1>::value == 1, ""); |
| 409 | static_assert(sum<23>::value == 23, ""); |
| 410 | static_assert(sum<1, 2>::value == 3, ""); |
| 411 | static_assert(sum<5, 5, 11>::value == 21, ""); |
| 412 | static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, ""); |
| 413 | |
| 414 | } |
| 415 | |
| 416 | // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae |
| 417 | // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function |
| 418 | // because of this. |
| 419 | namespace test_template_alias_sfinae |
| 420 | { |
| 421 | |
| 422 | struct foo {}; |
| 423 | |
| 424 | template<typename T> |
| 425 | using member = typename T::member_type; |
| 426 | |
| 427 | template<typename T> |
| 428 | void func(...) {} |
| 429 | |
| 430 | template<typename T> |
| 431 | void func(member<T>*) {} |
| 432 | |
| 433 | void test(); |
| 434 | |
| 435 | void test() { func<foo>(0); } |
| 436 | |
| 437 | } |
| 438 | |
| 439 | } // namespace cxx11 |
| 440 | |
| 441 | #endif // __cplusplus >= 201103L |
| 442 | |
| 443 | ]]) |
| 444 | |
| 445 | |
| 446 | dnl Tests for new features in C++14 |
| 447 | |
| 448 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[ |
| 449 | |
| 450 | // If the compiler admits that it is not ready for C++14, why torture it? |
| 451 | // Hopefully, this will speed up the test. |
| 452 | |
| 453 | #ifndef __cplusplus |
| 454 | |
| 455 | #error "This is not a C++ compiler" |
| 456 | |
| 457 | #elif __cplusplus < 201402L |
| 458 | |
| 459 | #error "This is not a C++14 compiler" |
| 460 | |
| 461 | #else |
| 462 | |
| 463 | namespace cxx14 |
| 464 | { |
| 465 | |
| 466 | namespace test_polymorphic_lambdas |
| 467 | { |
| 468 | |
| 469 | int |
| 470 | test() |
| 471 | { |
| 472 | const auto lambda = [](auto&&... args){ |
| 473 | const auto istiny = [](auto x){ |
| 474 | return (sizeof(x) == 1UL) ? 1 : 0; |
| 475 | }; |
| 476 | const int aretiny[] = { istiny(args)... }; |
| 477 | return aretiny[0]; |
| 478 | }; |
| 479 | return lambda(1, 1L, 1.0f, '1'); |
| 480 | } |
| 481 | |
| 482 | } |
| 483 | |
| 484 | namespace test_binary_literals |
| 485 | { |
| 486 | |
| 487 | constexpr auto ivii = 0b0000000000101010; |
| 488 | static_assert(ivii == 42, "wrong value"); |
| 489 | |
| 490 | } |
| 491 | |
| 492 | namespace test_generalized_constexpr |
| 493 | { |
| 494 | |
| 495 | template < typename CharT > |
| 496 | constexpr unsigned long |
| 497 | strlen_c(const CharT *const s) noexcept |
| 498 | { |
| 499 | auto length = 0UL; |
| 500 | for (auto p = s; *p; ++p) |
| 501 | ++length; |
| 502 | return length; |
| 503 | } |
| 504 | |
| 505 | static_assert(strlen_c("") == 0UL, ""); |
| 506 | static_assert(strlen_c("x") == 1UL, ""); |
| 507 | static_assert(strlen_c("test") == 4UL, ""); |
| 508 | static_assert(strlen_c("another\0test") == 7UL, ""); |
| 509 | |
| 510 | } |
| 511 | |
| 512 | namespace test_lambda_init_capture |
| 513 | { |
| 514 | |
| 515 | int |
| 516 | test() |
| 517 | { |
| 518 | auto x = 0; |
| 519 | const auto lambda1 = [a = x](int b){ return a + b; }; |
| 520 | const auto lambda2 = [a = lambda1(x)](){ return a; }; |
| 521 | return lambda2(); |
| 522 | } |
| 523 | |
| 524 | } |
| 525 | |
| 526 | namespace test_digit_seperators |
| 527 | { |
| 528 | |
| 529 | constexpr auto ten_million = 100'000'000; |
| 530 | static_assert(ten_million == 100000000, ""); |
| 531 | |
| 532 | } |
| 533 | |
| 534 | namespace test_return_type_deduction |
| 535 | { |
| 536 | |
| 537 | auto f(int& x) { return x; } |
| 538 | decltype(auto) g(int& x) { return x; } |
| 539 | |
| 540 | template < typename T1, typename T2 > |
| 541 | struct is_same |
| 542 | { |
| 543 | static constexpr auto value = false; |
| 544 | }; |
| 545 | |
| 546 | template < typename T > |
| 547 | struct is_same<T, T> |
| 548 | { |
| 549 | static constexpr auto value = true; |
| 550 | }; |
| 551 | |
| 552 | int |
| 553 | test() |
| 554 | { |
| 555 | auto x = 0; |
| 556 | static_assert(is_same<int, decltype(f(x))>::value, ""); |
| 557 | static_assert(is_same<int&, decltype(g(x))>::value, ""); |
| 558 | return x; |
| 559 | } |
| 560 | |
| 561 | } |
| 562 | |
| 563 | } // namespace cxx14 |
| 564 | |
| 565 | #endif // __cplusplus >= 201402L |
| 566 | |
| 567 | ]]) |