1 #ifndef PETSC_PREPROCESSOR_MACROS_H 2 #define PETSC_PREPROCESSOR_MACROS_H 3 4 #include <petscconf.h> 5 #include <petscconf_poison.h> /* for PetscDefined() error checking */ 6 7 /* SUBMANSEC = Sys */ 8 9 #if defined(__cplusplus) 10 #if __cplusplus <= 201103L 11 #define PETSC_CPP_VERSION 11 12 #elif __cplusplus <= 201402L 13 #define PETSC_CPP_VERSION 14 14 #elif __cplusplus <= 201703L 15 #define PETSC_CPP_VERSION 17 16 #elif __cplusplus <= 202002L 17 #define PETSC_CPP_VERSION 20 18 #else 19 #define PETSC_CPP_VERSION 22 // current year, or date of c++2b ratification 20 #endif 21 #endif // __cplusplus 22 23 #ifndef PETSC_CPP_VERSION 24 #define PETSC_CPP_VERSION 0 25 #endif 26 27 #if defined(__STDC_VERSION__) 28 #if __STDC_VERSION__ <= 199901L 29 // C99 except that 99 is >= 11 or 17 so we shorten it to 9 instead 30 #define PETSC_C_VERSION 9 31 #elif __STDC_VERSION__ <= 201112L 32 #define PETSC_C_VERSION 11 33 #elif __STDC_VERSION__ <= 201710L 34 #define PETSC_C_VERSION 17 35 #else 36 #define PETSC_C_VERSION 22 // current year, or date of c2b ratification 37 #endif 38 #endif // __STDC_VERSION__ 39 40 #ifndef PETSC_C_VERSION 41 #define PETSC_C_VERSION 0 42 #endif 43 44 /* ========================================================================== */ 45 /* This facilitates using the C version of PETSc from C++ and the C++ version from C. */ 46 #if defined(__cplusplus) 47 #define PETSC_FUNCTION_NAME PETSC_FUNCTION_NAME_CXX 48 #else 49 #define PETSC_FUNCTION_NAME PETSC_FUNCTION_NAME_C 50 #endif 51 52 /* ========================================================================== */ 53 /* Since PETSc manages its own extern "C" handling users should never include PETSc include 54 * files within extern "C". This will generate a compiler error if a user does put the include 55 * file within an extern "C". 56 */ 57 #if defined(__cplusplus) 58 void assert_never_put_petsc_headers_inside_an_extern_c(int); 59 void assert_never_put_petsc_headers_inside_an_extern_c(double); 60 #endif 61 62 #if defined(__cplusplus) 63 #define PETSC_RESTRICT PETSC_CXX_RESTRICT 64 #else 65 #define PETSC_RESTRICT restrict 66 #endif 67 68 #define PETSC_INLINE PETSC_DEPRECATED_MACRO("GCC warning \"PETSC_INLINE is deprecated (since version 3.17)\"") inline 69 #define PETSC_STATIC_INLINE PETSC_DEPRECATED_MACRO("GCC warning \"PETSC_STATIC_INLINE is deprecated (since version 3.17)\"") static inline 70 71 #if defined(_WIN32) && defined(PETSC_USE_SHARED_LIBRARIES) /* For Win32 shared libraries */ 72 #define PETSC_DLLEXPORT __declspec(dllexport) 73 #define PETSC_DLLIMPORT __declspec(dllimport) 74 #define PETSC_VISIBILITY_INTERNAL 75 #elif defined(__cplusplus) && defined(PETSC_USE_VISIBILITY_CXX) 76 #define PETSC_DLLEXPORT __attribute__((visibility("default"))) 77 #define PETSC_DLLIMPORT __attribute__((visibility("default"))) 78 #define PETSC_VISIBILITY_INTERNAL __attribute__((visibility("hidden"))) 79 #elif !defined(__cplusplus) && defined(PETSC_USE_VISIBILITY_C) 80 #define PETSC_DLLEXPORT __attribute__((visibility("default"))) 81 #define PETSC_DLLIMPORT __attribute__((visibility("default"))) 82 #define PETSC_VISIBILITY_INTERNAL __attribute__((visibility("hidden"))) 83 #else 84 #define PETSC_DLLEXPORT 85 #define PETSC_DLLIMPORT 86 #define PETSC_VISIBILITY_INTERNAL 87 #endif 88 89 #if defined(petsc_EXPORTS) /* CMake defines this when building the shared library */ 90 #define PETSC_VISIBILITY_PUBLIC PETSC_DLLEXPORT 91 #else /* Win32 users need this to import symbols from petsc.dll */ 92 #define PETSC_VISIBILITY_PUBLIC PETSC_DLLIMPORT 93 #endif 94 95 /* Functions tagged with PETSC_EXTERN in the header files are always defined as extern "C" when 96 * compiled with C++ so they may be used from C and are always visible in the shared libraries 97 */ 98 #if defined(__cplusplus) 99 #define PETSC_EXTERN extern "C" PETSC_VISIBILITY_PUBLIC 100 #define PETSC_EXTERN_TYPEDEF extern "C" 101 #define PETSC_INTERN extern "C" PETSC_VISIBILITY_INTERNAL 102 #else 103 #define PETSC_EXTERN extern PETSC_VISIBILITY_PUBLIC 104 #define PETSC_EXTERN_TYPEDEF 105 #define PETSC_INTERN extern PETSC_VISIBILITY_INTERNAL 106 #endif 107 108 #if defined(PETSC_USE_SINGLE_LIBRARY) 109 #define PETSC_SINGLE_LIBRARY_INTERN PETSC_INTERN 110 #else 111 #define PETSC_SINGLE_LIBRARY_INTERN PETSC_EXTERN 112 #endif 113 114 #if !defined(__has_feature) 115 #define __has_feature(x) 0 116 #endif 117 118 /*MC 119 PetscHasAttribute - Determine whether a particular __attribute__ is supported by the compiler 120 121 Synopsis: 122 #include <petscmacros.h> 123 int PetscHasAttribute(name) 124 125 Input Parameter: 126 . name - The name of the attribute to test 127 128 Notes: 129 name should be identical to what you might pass to the __attribute__ declaration itself -- 130 plain, unbroken text. 131 132 As `PetscHasAttribute()` is wrapper over the function-like macro `__has_attribute()`, the 133 exact type and value returned is implementation defined. In practice however, it usually 134 returns `1` if the attribute is supported and `0` if the attribute is not supported. 135 136 Example Usage: 137 Typical usage is using the preprocessor 138 139 .vb 140 #if PetscHasAttribute(always_inline) 141 # define MY_ALWAYS_INLINE __attribute__((always_inline)) 142 #else 143 # define MY_ALWAYS_INLINE 144 #endif 145 146 void foo(void) MY_ALWAYS_INLINE; 147 .ve 148 149 but it can also be used in regular code 150 151 .vb 152 if (PetscHasAttribute(some_attribute)) { 153 foo(); 154 } else { 155 bar(); 156 } 157 .ve 158 159 Level: intermediate 160 161 .seealso: `PetscHasBuiltin()`, `PetscDefined()`, `PetscLikely()`, `PetscUnlikely()`, 162 `PETSC_ATTRIBUTE_FORMAT`, `PETSC_ATTRIBUTE_MAY_ALIAS` 163 M*/ 164 #if !defined(__has_attribute) 165 #define __has_attribute(x) 0 166 #endif 167 #define PetscHasAttribute(name) __has_attribute(name) 168 169 /*MC 170 PetscHasBuiltin - Determine whether a particular builtin method is supported by the compiler 171 172 Synopsis: 173 #include <petscmacros.h> 174 int PetscHasBuiltin(name) 175 176 Input Parameter: 177 . name - the name of the builtin routine 178 179 Notes: 180 Evaluates to `1` if the builtin is supported and `0` otherwise. Note the term "evaluates" 181 (vs "expands") is deliberate; even though `PetscHasBuiltin()` is a macro the underlying 182 detector is itself is a compiler extension with implementation-defined return type and 183 semantics. Some compilers implement it as a macro, others as a compiler function. In practice 184 however, all supporting compilers return an integer boolean as described. 185 186 Example Usage: 187 Typical usage is in preprocessor directives 188 189 .vb 190 #if PetscHasBuiltin(__builtin_trap) 191 __builtin_trap(); 192 #else 193 abort(); 194 #endif 195 .ve 196 197 But it may also be used in regular code 198 199 .vb 200 if (PetscHasBuiltin(__builtin_alloca)) { 201 foo(); 202 } else { 203 bar(); 204 } 205 .ve 206 207 Level: intermediate 208 209 .seealso: `PetscHasAttribute()`, `PetscAssume()` 210 M*/ 211 #if !defined(__has_builtin) 212 #define __has_builtin(x) 0 213 #endif 214 // clangs __has_builtin prior to clang 10 did not properly handle non-function builtins such as 215 // __builtin_types_compatible_p which take types or other non-functiony things as 216 // arguments. The correct way to detect these then is to use __is_identifier (also a clang 217 // extension). GCC has always worked as expected. see https://stackoverflow.com/a/45043153 218 #if defined(__clang__) && defined(__clang_major__) && (__clang_major__ < 10) && defined(__is_identifier) 219 #define PetscHasBuiltin(name) __is_identifier(name) 220 #else 221 #define PetscHasBuiltin(name) __has_builtin(name) 222 #endif 223 224 #if !defined(PETSC_SKIP_ATTRIBUTE_MPI_TYPE_TAG) 225 /* 226 Support for Clang (>=3.2) matching type tag arguments with void* buffer types. 227 This allows the compiler to detect cases where the MPI datatype argument passed to a MPI routine 228 does not match the actual type of the argument being passed in 229 */ 230 #if PetscHasAttribute(pointer_with_type_tag) 231 #define PETSC_ATTRIBUTE_MPI_POINTER_WITH_TYPE(bufno, typeno) __attribute__((pointer_with_type_tag(MPI, bufno, typeno))) 232 #endif 233 234 #if PetscHasAttribute(type_tag_for_datatype) 235 #define PETSC_ATTRIBUTE_MPI_TYPE_TAG(type) __attribute__((type_tag_for_datatype(MPI, type))) 236 #define PETSC_ATTRIBUTE_MPI_TYPE_TAG_LAYOUT_COMPATIBLE(type) __attribute__((type_tag_for_datatype(MPI, type, layout_compatible))) 237 #endif 238 #endif // PETSC_SKIP_ATTRIBUTE_MPI_TYPE_TAG 239 240 #ifndef PETSC_ATTRIBUTE_MPI_POINTER_WITH_TYPE 241 #define PETSC_ATTRIBUTE_MPI_POINTER_WITH_TYPE(bufno, typeno) 242 #endif 243 244 #ifndef PETSC_ATTRIBUTE_MPI_TYPE_TAG 245 #define PETSC_ATTRIBUTE_MPI_TYPE_TAG(type) 246 #endif 247 248 #ifndef PETSC_ATTRIBUTE_MPI_TYPE_TAG_LAYOUT_COMPATIBLE 249 #define PETSC_ATTRIBUTE_MPI_TYPE_TAG_LAYOUT_COMPATIBLE(type) 250 #endif 251 252 /*MC 253 PETSC_ATTRIBUTE_FORMAT - Indicate to the compiler that specified arguments should be treated 254 as format specifiers and checked for validity 255 256 Synopsis: 257 #include <petscmacros.h> 258 <attribute declaration> PETSC_ATTRIBUTE_FORMAT(int strIdx, int vaArgIdx) 259 260 Input Parameters: 261 + strIdx - The (1-indexed) location of the format string in the argument list 262 - vaArgIdx - The (1-indexed) location of the first formattable argument in the argument list 263 264 Level: developer 265 266 Notes: 267 This function attribute causes the compiler to issue warnings when the format specifier does 268 not match the type of the variable that will be formatted, or when there exists a mismatch 269 between the number of format specifiers and variables to be formatted. It is safe to use this 270 macro if your compiler does not support format specifier checking (though this is 271 exceeedingly rare). 272 273 Both `strIdx` and `vaArgIdx` must be compile-time constant integer literals and cannot have the 274 same value. 275 276 The arguments to be formatted (and therefore checked by the compiler) must be "contiguous" in 277 the argument list, that is, there is no way to indicate gaps which should not be checked. 278 279 Definition is suppressed by defining `PETSC_SKIP_ATTRIBUTE_FORMAT` prior to including PETSc 280 header files. In this case the macro will expand empty. 281 282 Example Usage: 283 .vb 284 // format string is 2nd argument, variable argument list containing args is 3rd argument 285 void my_printf(void *obj, const char *fmt_string, ...) PETSC_ATTRIBUTE_FORMAT(2,3) 286 287 int x = 1; 288 double y = 50.0; 289 290 my_printf(NULL,"%g",x); // WARNING, format specifier does not match for 'int'! 291 my_printf(NULL,"%d",x,y); // WARNING, more arguments than format specifiers! 292 my_printf(NULL,"%d %g",x,y); // OK 293 .ve 294 295 .seealso: `PETSC_ATTRIBUTE_COLD`, `PetscHasAttribute()` 296 M*/ 297 #if PetscHasAttribute(format) && !defined(PETSC_SKIP_ATTRIBUTE_FORMAT) 298 #define PETSC_ATTRIBUTE_FORMAT(strIdx, vaArgIdx) __attribute__((format(printf, strIdx, vaArgIdx))) 299 #else 300 #define PETSC_ATTRIBUTE_FORMAT(strIdx, vaArgIdx) 301 #endif 302 303 /*MC 304 PETSC_ATTRIBUTE_COLD - Indicate to the compiler that a function is very unlikely to be 305 executed 306 307 Level: intermediate 308 309 Notes: 310 The marked function is often optimized for size rather than speed and may be grouped alongside 311 other equally frigid routines improving code locality of lukewarm or hotter parts of program. 312 313 The paths leading to cold functions are usually automatically marked as unlikely by the 314 compiler. It may thus be useful to mark functions used to handle unlikely conditions -- such 315 as error handlers -- as cold to improve optimization of the surrounding temperate functions. 316 317 Example Usage: 318 .vb 319 void my_error_handler(...) PETSC_ATTRIBUTE_COLD; 320 321 if (temperature < 0) { 322 return my_error_handler(...); // chilly! 323 } 324 .ve 325 326 .seealso: `PetscUnlikely()`, `PetscUnlikelyDebug()`, `PetscLikely()`, `PetscLikelyDebug()`, 327 `PetscUnreachable()`, `PETSC_ATTRIBUTE_FORMAT` 328 M*/ 329 #if PetscHasAttribute(__cold__) 330 #define PETSC_ATTRIBUTE_COLD __attribute__((__cold__)) 331 #elif PetscHasAttribute(cold) /* some implementations (old gcc) use no underscores */ 332 #define PETSC_ATTRIBUTE_COLD __attribute__((cold)) 333 #else 334 #define PETSC_ATTRIBUTE_COLD 335 #endif 336 337 /*MC 338 PETSC_ATTRIBUTE_MAY_ALIAS - Indicate to the compiler that a type is not 339 subjected to type-based alias analysis, but is instead assumed to be able to 340 alias any other type of objects 341 342 Example Usage: 343 .vb 344 typedef PetscScalar PetscScalarAlias PETSC_ATTRIBUTE_MAY_ALIAS; 345 346 PetscReal *pointer; 347 PetscScalarAlias *other_pointer = reinterpret_cast<PetscScalarAlias *>(pointer); 348 .ve 349 350 Level: advanced 351 352 .seealso: `PetscHasAttribute()` 353 M*/ 354 #if PetscHasAttribute(may_alias) && !defined(PETSC_SKIP_ATTRIBUTE_MAY_ALIAS) 355 #define PETSC_ATTRIBUTE_MAY_ALIAS __attribute__((may_alias)) 356 #else 357 #define PETSC_ATTRIBUTE_MAY_ALIAS 358 #endif 359 360 /*MC 361 PETSC_NULLPTR - Standard way of indicating a null value or pointer 362 363 No Fortran Support 364 365 Level: beginner 366 367 Notes: 368 Equivalent to `NULL` in C source, and `nullptr` in C++ source. Note that for the purposes of 369 interoperability between C and C++, setting a pointer to `PETSC_NULLPTR` in C++ is functonially 370 equivalent to setting the same pointer to `NULL` in C. That is to say that the following 371 expressions are equivalent\: 372 373 .vb 374 ptr == PETSC_NULLPTR 375 ptr == NULL 376 ptr == 0 377 !ptr 378 379 ptr = PETSC_NULLPTR 380 ptr = NULL 381 ptr = 0 382 .ve 383 384 and for completeness' sake\: 385 386 .vb 387 PETSC_NULLPTR == NULL 388 .ve 389 390 Example Usage: 391 .vb 392 // may be used in place of '\0' or other such teminators in the definition of char arrays 393 const char *const MyEnumTypes[] = { 394 "foo", 395 "bar", 396 PETSC_NULLPTR 397 }; 398 399 // may be used to nullify objects 400 PetscObject obj = PETSC_NULLPTR; 401 402 // may be used in any function expecting NULL 403 PetscInfo(PETSC_NULLPTR,"Lorem Ipsum Dolor"); 404 .ve 405 406 Developer Notes: 407 `PETSC_NULLPTR` must be used in place of `NULL` in all C++ source files. Using `NULL` in source 408 files compiled with a C++ compiler may lead to unexpected side-effects in function overload 409 resolution and/or compiler warnings. 410 411 .seealso: `PETSC_CONSTEXPR_14`, `PETSC_NODISCARD` 412 M*/ 413 414 /*MC 415 PETSC_CONSTEXPR_14 - C++14 constexpr 416 417 No Fortran Support 418 419 Level: beginner 420 421 Notes: 422 Equivalent to `constexpr` when using a C++ compiler that supports C++14. Expands to nothing 423 if the C++ compiler does not support C++14 or when not compiling with a C++ compiler. Note 424 that this cannot be used in cases where an empty expansion would result in invalid code. It 425 is safe to use this in C source files. 426 427 Example Usage: 428 .vb 429 PETSC_CONSTEXPR_14 int factorial(int n) 430 { 431 int r = 1; 432 433 do { 434 r *= n; 435 } while (--n); 436 return r; 437 } 438 .ve 439 440 .seealso: `PETSC_NULLPTR`, `PETSC_NODISCARD` 441 M*/ 442 443 /*MC 444 PETSC_NODISCARD - Mark the return value of a function as non-discardable 445 446 Not available in Fortran 447 448 Level: beginner 449 450 Notes: 451 Hints to the compiler that the return value of a function must be captured. A diagnostic may 452 (but is not required to) be emitted if the value is discarded. It is safe to use this in both 453 C and C++ source files. 454 455 In this context "captured" means assigning the return value of a function to a named 456 variable or casting it to `void`. Between the two, assigning to a named variable is the most 457 portable way of silencing any warnings, since `PETSC_NODISCARD` may expand to GCC's 458 `__attribute__((warn_unused_result))` which will still emit warnings when casting results to 459 `void`. 460 461 Example Usage: 462 .vb 463 class Foo 464 { 465 int x; 466 467 public: 468 PETSC_NODISCARD Foo(int y) : x(y) { } 469 }; 470 471 PETSC_NODISCARD int factorial(int n) 472 { 473 return n <= 1 ? 1 : (n * factorial(n - 1)); 474 } 475 476 factorial(10); // Warning: ignoring return value of function declared 'nodiscard' 477 auto x = factorial(10); // OK, capturing return value 478 (void)factorial(10); // Maybe OK, casting to void 479 auto y = factorial(10); // OK, capturing in y (and casting y to void to silence 480 (void)y; // set-but-not-used warnings) 481 482 Foo(x); // Warning: Ignoring temporary created by a constructor declared 'nodiscard' 483 auto f = Foo(x); // OK, capturing constructed object 484 (void)Foo(x); // Maybe OK, casting to void 485 auto g = Foo(x); // OK, capturing in g (and casting g to void to silence set-but-not-used 486 (void)g; // warnings) 487 .ve 488 489 .seealso: `PETSC_NULLPTR`, `PETSC_CONSTEXPR_14` 490 M*/ 491 492 /* C++11 features */ 493 #if defined(__cplusplus) || (PETSC_C_VERSION >= 23) 494 #define PETSC_NULLPTR nullptr 495 #else 496 #define PETSC_NULLPTR NULL 497 #endif 498 499 /* C++14 features */ 500 #if PETSC_CPP_VERSION >= 14 501 #define PETSC_CONSTEXPR_14 constexpr 502 #else 503 #define PETSC_CONSTEXPR_14 504 #endif 505 506 /* C++17 features */ 507 #if PETSC_CPP_VERSION >= 17 508 #define PETSC_CONSTEXPR_17 constexpr 509 #else 510 #define PETSC_CONSTEXPR_17 511 #endif 512 513 #if (PETSC_CPP_VERSION >= 17) || (PETSC_C_VERSION >= 23) 514 #define PETSC_NODISCARD [[nodiscard]] 515 #elif PetscHasAttribute(warn_unused_result) 516 #define PETSC_NODISCARD __attribute__((warn_unused_result)) 517 #else 518 #define PETSC_NODISCARD 519 #endif 520 521 #include <petscversion.h> 522 #define PETSC_AUTHOR_INFO " The PETSc Team\n petsc-maint@mcs.anl.gov\n https://petsc.org/\n" 523 524 /* designated initializers since C99 and C++20, MSVC never supports them though */ 525 #if defined(_MSC_VER) || (defined(__cplusplus) && (PETSC_CPP_VERSION < 20)) 526 #define PetscDesignatedInitializer(name, ...) __VA_ARGS__ 527 #else 528 #define PetscDesignatedInitializer(name, ...) .name = __VA_ARGS__ 529 #endif 530 531 /*MC 532 PetscUnlikely - Hints the compiler that the given condition is usually false 533 534 Synopsis: 535 #include <petscmacros.h> 536 bool PetscUnlikely(bool cond) 537 538 Not Collective; No Fortran Support 539 540 Input Parameter: 541 . cond - Boolean expression 542 543 Level: advanced 544 545 Notes: 546 This returns the same truth value, it is only a hint to compilers that the result of cond is 547 unlikely to be true. 548 549 Example usage: 550 .vb 551 if (PetscUnlikely(cond)) { 552 foo(); // cold path 553 } else { 554 bar(); // hot path 555 } 556 .ve 557 558 .seealso: `PetscLikely()`, `PetscUnlikelyDebug()`, `PetscCall()`, `PetscDefined()`, `PetscHasAttribute()`, 559 `PETSC_ATTRIBUTE_COLD` 560 M*/ 561 562 /*MC 563 PetscLikely - Hints the compiler that the given condition is usually true 564 565 Synopsis: 566 #include <petscmacros.h> 567 bool PetscLikely(bool cond) 568 569 Not Collective; No Fortran Support 570 571 Input Parameter: 572 . cond - Boolean expression 573 574 Level: advanced 575 576 Notes: 577 This returns the same truth value, it is only a hint to compilers that the result of cond is 578 likely to be true. 579 580 Example usage: 581 .vb 582 if (PetscLikely(cond)) { 583 foo(); // hot path 584 } else { 585 bar(); // cold path 586 } 587 .ve 588 589 .seealso: `PetscUnlikely()`, `PetscDefined()`, `PetscHasAttribute()` 590 `PETSC_ATTRIBUTE_COLD` 591 M*/ 592 #if defined(PETSC_HAVE_BUILTIN_EXPECT) 593 #define PetscUnlikely(cond) __builtin_expect(!!(cond), 0) 594 #define PetscLikely(cond) __builtin_expect(!!(cond), 1) 595 #else 596 #define PetscUnlikely(cond) (cond) 597 #define PetscLikely(cond) (cond) 598 #endif 599 600 /*MC 601 PetscUnreachable - Indicate to the compiler that a code-path is logically unreachable 602 603 Synopsis: 604 #include <petscmacros.h> 605 void PetscUnreachable(void) 606 607 Level: advanced 608 609 Notes: 610 Indicates to the compiler (usually via some built-in) that a particular code path is always 611 unreachable. Behavior is undefined if this function is ever executed, the user can expect an 612 unceremonious crash. 613 614 Example usage: 615 Useful in situations such as switches over enums where not all enumeration values are 616 explicitly covered by the switch 617 618 .vb 619 typedef enum {RED, GREEN, BLUE} Color; 620 621 int foo(Color c) 622 { 623 // it is known to programmer (or checked previously) that c is either RED or GREEN 624 // but compiler may not be able to deduce this and/or emit spurious warnings 625 switch (c) { 626 case RED: 627 return bar(); 628 case GREEN: 629 return baz(); 630 default: 631 PetscUnreachable(); // program is ill-formed if executed 632 } 633 } 634 .ve 635 636 .seealso: `SETERRABORT()`, `PETSCABORT()`, `PETSC_ATTRIBUTE_COLD`, `PetscAssume()` 637 M*/ 638 #if PETSC_CPP_VERSION >= 23 639 #include <utility> 640 #define PetscUnreachable() std::unreachable() 641 #elif defined(__GNUC__) 642 /* GCC 4.8+, Clang, Intel and other compilers compatible with GCC (-std=c++0x or above) */ 643 #define PetscUnreachable() __builtin_unreachable() 644 #elif defined(_MSC_VER) /* MSVC */ 645 #define PetscUnreachable() __assume(0) 646 #else /* ??? */ 647 #define PetscUnreachable() SETERRABORT(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Code path explicitly marked as unreachable executed") 648 #endif 649 650 /*MC 651 PetscAssume - Indicate to the compiler a condition that is defined to be true 652 653 Synopsis: 654 #include <petscmacros.h> 655 void PetscAssume(bool cond) 656 657 Input Parameter: 658 . cond - Boolean expression 659 660 Level: advanced 661 662 Notes: 663 If supported by the compiler, `cond` is used to inform the optimizer of an invariant 664 truth. The argument itself is never evaluated, so any side effects of the expression will be 665 discarded. This macro is used in `PetscAssert()` to retain information gained from debug 666 checks that would be lost in optimized builds. For example\: 667 668 .vb 669 PetscErrorCode foo(PetscInt x) { 670 671 PetscAssert(x >= 0, ...); 672 } 673 .ve 674 675 The assertion checks that `x` is positive when debugging is enabled (and returns from `foo()` 676 if it is not). This implicitly informs the optimizer that `x` cannot be negative. However, 677 when debugging is disabled any `PetscAssert()` checks are tautologically false, and hence the 678 optimizer cannot deduce any information from them. 679 680 Due to compiler limitations `PetscAssume()` works best when `cond` involves 681 constants. Certain compilers do not yet propagate symbolic inequalities i.e.\: 682 683 .vb 684 int a, b, var_five; 685 686 // BEST, all supporting compilers will understand a cannot be >= 5 687 PetscAssume(a < 5); 688 689 // OK, some compilers may understand that a cannot be >= 5 690 PetscAssume(a <= b && b < 5); 691 692 // WORST, most compilers will not get the memo 693 PetscAssume(a <= b && b < var_five); 694 .ve 695 696 If the condition is violated at runtime then behavior is wholly undefined. If the 697 condition is violated at compile-time, the condition "supersedes" the compile-time violation 698 and the program is ill-formed, no diagnostic required. For example consider the following\: 699 700 .vb 701 PetscInt x = 0; 702 703 PetscAssume(x != 0); 704 if (x == 0) { 705 x += 10; 706 } else { 707 popen("rm -rf /", "w"); 708 } 709 .ve 710 711 Even though `x` is demonstrably `0` the compiler may opt to\: 712 713 - emit an unconditional `popen("rm -rf /", "w")` 714 - ignore `PetscAssume()` altogether and emit the correct path of `x += 10` 715 - reformat the primary disk partition 716 717 .seealso: `PetscAssert()` 718 M*/ 719 #if PETSC_CPP_VERSION >= 23 720 #define PetscAssume(...) [[assume(__VA_ARGS__)]] 721 #elif defined(_MSC_VER) // msvc 722 #define PetscAssume(...) __assume(__VA_ARGS__) 723 #elif defined(__clang__) && PetscHasBuiltin(__builtin_assume) // clang 724 #define PetscAssume(...) \ 725 do { \ 726 _Pragma("clang diagnostic push"); \ 727 _Pragma("clang diagnostic ignored \"-Wassume\""); \ 728 __builtin_assume(__VA_ARGS__); \ 729 _Pragma("clang diagnostic pop"); \ 730 } while (0) 731 #else // gcc (and really old clang) 732 // gcc does not have its own __builtin_assume() intrinsic. One could fake it via 733 // 734 // if (PetscUnlikely(!cond)) PetscUnreachable(); 735 // 736 // but this it unsavory because the side effects of cond are not guaranteed to be 737 // discarded. Though in most circumstances gcc will optimize out the if (because any evaluation 738 // for which cond is false would be undefined results in undefined behavior anyway) it cannot 739 // always do so. This is especially the case for opaque or non-inline function calls: 740 // 741 // extern int bar(int); 742 // 743 // int foo(int x) { 744 // PetscAssume(bar(x) == 2); 745 // if (bar(x) == 2) { 746 // return 1; 747 // } else { 748 // return 0; 749 // } 750 // } 751 // 752 // Here gcc would (if just using builtin_expect()) emit 2 calls to bar(). Note we still have 753 // cond "tested" in the condition, but this is done to silence unused-but-set variable warnings 754 #define PetscAssume(...) \ 755 do { \ 756 if (0 && (__VA_ARGS__)) PetscUnreachable(); \ 757 } while (0) 758 #endif 759 760 /*MC 761 PetscExpand - Expand macro argument 762 763 Synopsis: 764 #include <petscmacros.h> 765 <macro-expansion> PetscExpand(x) 766 767 Input Parameter: 768 . x - The preprocessor token to expand 769 770 Level: beginner 771 772 .seealso: `PetscStringize()`, `PetscConcat()` 773 M*/ 774 #define PetscExpand_(...) __VA_ARGS__ 775 #define PetscExpand(...) PetscExpand_(__VA_ARGS__) 776 777 /*MC 778 PetscStringize - Stringize a token 779 780 Synopsis: 781 #include <petscmacros.h> 782 const char* PetscStringize(x) 783 784 No Fortran Support 785 786 Input Parameter: 787 . x - The token you would like to stringize 788 789 Output Parameter: 790 . <return-value> - The string representation of `x` 791 792 Level: beginner 793 794 Note: 795 `PetscStringize()` expands `x` before stringizing it, if you do not wish to do so, use 796 `PetscStringize_()` instead. 797 798 Example Usage: 799 .vb 800 #define MY_OTHER_VAR hello there 801 #define MY_VAR MY_OTHER_VAR 802 803 PetscStringize(MY_VAR) -> "hello there" 804 PetscStringize_(MY_VAR) -> "MY_VAR" 805 806 int foo; 807 PetscStringize(foo) -> "foo" 808 PetscStringize_(foo) -> "foo" 809 .ve 810 811 .seealso: `PetscConcat()`, `PetscExpandToNothing()`, `PetscExpand()` 812 M*/ 813 #define PetscStringize_(...) #__VA_ARGS__ 814 #define PetscStringize(...) PetscStringize_(__VA_ARGS__) 815 816 /*MC 817 PetscConcat - Concatenate two tokens 818 819 Synopsis: 820 #include <petscmacros.h> 821 <macro-expansion> PetscConcat(x, y) 822 823 No Fortran Support 824 825 Input Parameters: 826 + x - First token 827 - y - Second token 828 829 Level: beginner 830 831 Note: 832 `PetscConcat()` will expand both arguments before pasting them together, use `PetscConcat_()` 833 if you don't want to expand them. 834 835 Example usage: 836 .vb 837 PetscConcat(hello,there) -> hellothere 838 839 #define HELLO hello 840 PetscConcat(HELLO,there) -> hellothere 841 PetscConcat_(HELLO,there) -> HELLOthere 842 .ve 843 844 .seealso: `PetscStringize()`, `PetscExpand()` 845 M*/ 846 #define PetscConcat_(x, y) x##y 847 #define PetscConcat(x, y) PetscConcat_(x, y) 848 849 #define PETSC_INTERNAL_COMPL_0 1 850 #define PETSC_INTERNAL_COMPL_1 0 851 852 /*MC 853 PetscCompl - Expands to the integer complement of its argument 854 855 Synopsis: 856 #include <petscmacros.h> 857 int PetscCompl(b) 858 859 No Fortran Support 860 861 Input Parameter: 862 . b - Preprocessor variable, must expand to either integer literal 0 or 1 863 864 Output Parameter: 865 . <return-value> - Either integer literal 0 or 1 866 867 Level: beginner 868 869 Notes: 870 Expands to integer literal 0 if b expands to 1, or integer literal 1 if b expands to 871 0. Behaviour is undefined if b expands to anything else. PetscCompl() will expand its 872 argument before returning the complement. 873 874 This macro can be useful for negating `PetscDefined()` inside macros e.g. 875 876 $ #define PETSC_DONT_HAVE_FOO PetscCompl(PetscDefined(HAVE_FOO)) 877 878 Example usage: 879 .vb 880 #define MY_VAR 1 881 PetscCompl(MY_VAR) -> 0 882 883 #undef MY_VAR 884 #define MY_VAR 0 885 PetscCompl(MY_VAR) -> 1 886 .ve 887 888 .seealso: `PetscConcat()`, `PetscDefined()` 889 M*/ 890 #define PetscCompl(b) PetscConcat_(PETSC_INTERNAL_COMPL_, PetscExpand(b)) 891 892 /*MC 893 PetscDefined - Determine whether a boolean macro is defined 894 895 Synopsis: 896 #include <petscmacros.h> 897 int PetscDefined(def) 898 899 No Fortran Support 900 901 Input Parameter: 902 . def - PETSc-style preprocessor variable (without PETSC_ prepended!) 903 904 Output Parameter: 905 . <return-value> - Either integer literal 0 or 1 906 907 Level: intermediate 908 909 Notes: 910 `PetscDefined()` returns 1 if and only if "PETSC_ ## def" is defined (but empty) or defined to 911 integer literal 1. In all other cases, `PetscDefined()` returns integer literal 0. Therefore 912 this macro should not be used if its argument may be defined to a non-empty value other than 913 1. 914 915 The prefix "PETSC_" is automatically prepended to def. To avoid prepending "PETSC_", say to 916 add custom checks in user code, one should use `PetscDefined_()`. 917 918 $ #define FooDefined(d) PetscDefined_(PetscConcat(FOO_, d)) 919 920 Developer Notes: 921 Getting something that works in C and CPP for an arg that may or may not be defined is 922 tricky. Here, if we have "#define PETSC_HAVE_BOOGER 1" we match on the placeholder define, 923 insert the "0," for arg1 and generate the triplet (0, 1, 0). Then the last step cherry picks 924 the 2nd arg (a one). When PETSC_HAVE_BOOGER is not defined, we generate a (... 1, 0) pair, 925 and when the last step cherry picks the 2nd arg, we get a zero. 926 927 Our extra expansion via PetscDefined__take_second_expand() is needed with MSVC, which has a 928 nonconforming implementation of variadic macros. 929 930 Example Usage: 931 Suppose you would like to call either "foo()" or "bar()" depending on whether PETSC_USE_DEBUG 932 is defined then 933 934 .vb 935 #if PetscDefined(USE_DEBUG) 936 foo(); 937 #else 938 bar(); 939 #endif 940 941 // or alternatively within normal code 942 if (PetscDefined(USE_DEBUG)) { 943 foo(); 944 } else { 945 bar(); 946 } 947 .ve 948 949 is equivalent to 950 951 .vb 952 #if defined(PETSC_USE_DEBUG) 953 # if MY_DETECT_EMPTY_MACRO(PETSC_USE_DEBUG) // assuming you have such a macro 954 foo(); 955 # elif PETSC_USE_DEBUG == 1 956 foo(); 957 # else 958 bar(); 959 # endif 960 #else 961 bar(); 962 #endif 963 .ve 964 965 .seealso: `PetscHasAttribute()`, `PetscUnlikely()`, `PetscLikely()`, `PetscConcat()`, 966 `PetscExpandToNothing()`, `PetscCompl()` 967 M*/ 968 #define PetscDefined_arg_1 shift, 969 #define PetscDefined_arg_ shift, 970 #define PetscDefined__take_second_expanded(ignored, val, ...) val 971 #define PetscDefined__take_second_expand(args) PetscDefined__take_second_expanded args 972 #define PetscDefined__take_second(...) PetscDefined__take_second_expand((__VA_ARGS__)) 973 #define PetscDefined__(arg1_or_junk) PetscDefined__take_second(arg1_or_junk 1, 0, at_) 974 #define PetscDefined_(value) PetscDefined__(PetscConcat_(PetscDefined_arg_, value)) 975 #define PetscDefined(def) PetscDefined_(PetscConcat(PETSC_, def)) 976 977 /*MC 978 PetscUnlikelyDebug - Hints the compiler that the given condition is usually false, eliding 979 the check in optimized mode 980 981 Synopsis: 982 #include <petscmacros.h> 983 bool PetscUnlikelyDebug(bool cond) 984 985 No Fortran Support 986 987 Not Collective 988 989 Input Parameter: 990 . cond - Boolean expression 991 992 Level: advanced 993 994 Note: 995 This returns the same truth value, it is only a hint to compilers that the result of `cond` is 996 likely to be false. When PETSc is compiled in optimized mode this will always return 997 false. Additionally, `cond` is guaranteed to not be evaluated when PETSc is compiled in 998 optimized mode. 999 1000 Example usage: 1001 This routine is shorthand for checking both the condition and whether PetscDefined(USE_DEBUG) 1002 is true. So 1003 1004 .vb 1005 if (PetscUnlikelyDebug(cond)) { 1006 foo(); 1007 } else { 1008 bar(); 1009 } 1010 .ve 1011 1012 is equivalent to 1013 1014 .vb 1015 if (PetscDefined(USE_DEBUG)) { 1016 if (PetscUnlikely(cond)) { 1017 foo(); 1018 } else { 1019 bar(); 1020 } 1021 } else { 1022 bar(); 1023 } 1024 .ve 1025 1026 .seealso: `PetscUnlikely()`, `PetscLikely()`, `PetscCall()`, `SETERRQ` 1027 M*/ 1028 #define PetscUnlikelyDebug(cond) (PetscDefined(USE_DEBUG) && PetscUnlikely(cond)) 1029 1030 #if defined(PETSC_CLANG_STATIC_ANALYZER) 1031 // silence compiler warnings when using -pedantic, this is only used by the linter and it cares 1032 // not what ISO C allows 1033 #define PetscMacroReturns_(retexpr, ...) \ 1034 __extension__({ \ 1035 __VA_ARGS__; \ 1036 retexpr; \ 1037 }) 1038 #else 1039 #define PetscMacroReturns_(retexpr, ...) \ 1040 retexpr; \ 1041 do { \ 1042 __VA_ARGS__; \ 1043 } while (0) 1044 #endif 1045 1046 /*MC 1047 PetscExpandToNothing - Expands to absolutely nothing 1048 1049 Synopsis: 1050 #include <petscmacros.h> 1051 void PetscExpandToNothing(...) 1052 1053 No Fortran Support 1054 1055 Input Parameter: 1056 . __VA_ARGS__ - Anything at all 1057 1058 Level: beginner 1059 1060 Note: 1061 Must have at least 1 parameter. 1062 1063 Example usage: 1064 .vb 1065 PetscExpandToNothing(a,b,c) -> *nothing* 1066 .ve 1067 1068 .seealso: `PetscConcat()`, `PetscDefined()`, `PetscStringize()`, `PetscExpand()` 1069 M*/ 1070 #define PetscExpandToNothing(...) 1071 1072 /*MC 1073 PetscMacroReturns - Define a macro body that returns a value 1074 1075 Synopsis: 1076 #include <petscmacros.h> 1077 return_type PetscMacroReturns(return_type retexpr, ...) 1078 1079 Input Parameters: 1080 + retexpr - The value or expression that the macro should return 1081 - __VA_ARGS__ - The body of the macro 1082 1083 Level: intermediate 1084 1085 Notes: 1086 Due to limitations of the C-preprocessor retexpr cannot depend on symbols declared in the 1087 body of the macro and should not depend on values produced as a result of the expression. The 1088 user should not assume that the result of this macro is equivalent to a single logical source 1089 line. It is not portable to use macros defined using this one in conditional or loop bodies 1090 without enclosing them in curly braces\: 1091 1092 .vb 1093 #define FOO(arg1) PetscMacroReturns(0,arg1+=10) // returns 0 1094 1095 int err,x = 10; 1096 1097 if (...) err = FOO(x); // ERROR, body of FOO() executed outside the if statement 1098 if (...) { err = FOO(x); } // OK 1099 1100 for (...) err = FOO(x); // ERROR, body of FOO() executed outside the loop 1101 for (...) { err = FOO(x); } // OK 1102 .ve 1103 1104 It is also not portable to use this macro directly inside function call, conditional, loop, 1105 or switch statements\: 1106 1107 .vb 1108 extern void bar(int); 1109 1110 int ret = FOO(x); 1111 1112 bar(FOO(x)); // ERROR, may not compile 1113 bar(ret); // OK 1114 1115 if (FOO(x)) // ERROR, may not compile 1116 if (ret) // OK 1117 .ve 1118 1119 Example usage: 1120 .vb 1121 #define MY_SIMPLE_RETURNING_MACRO(arg1) PetscMacroReturns(0,arg1+=10) 1122 1123 int x = 10; 1124 int err = MY_SIMPLE_RETURNING_MACRO(x); // err = 0, x = 20 1125 1126 // multiline macros allowed, but must declare with line continuation as usual 1127 #define MY_COMPLEX_RETURNING_MACRO(arg1) PetscMacroReturns(0, \ 1128 if (arg1 > 10) { \ 1129 puts("big int!"); \ 1130 } else { \ 1131 return 7355608; \ 1132 } \ 1133 ) 1134 1135 // if retexpr contains commas, must enclose it with braces 1136 #define MY_COMPLEX_RETEXPR_MACRO_1() PetscMacroReturns(x+=10,0,body...) 1137 #define MY_COMPLEX_RETEXPR_MACRO_2() PetscMacroReturns((x+=10,0),body...) 1138 1139 int x = 10; 1140 int y = MY_COMPLEX_RETEXPR_MACRO_1(); // ERROR, y = x = 20 not 0 1141 int z = MY_COMPLEX_RETEXPR_MACRO_2(); // OK, y = 0, x = 20 1142 .ve 1143 1144 .seealso: `PetscExpand()`, `PetscConcat()`, `PetscStringize()` 1145 M*/ 1146 #define PetscMacroReturns(retexpr, ...) PetscMacroReturns_(retexpr, __VA_ARGS__) 1147 1148 #define PetscMacroReturnStandard(...) PetscMacroReturns(PETSC_SUCCESS, __VA_ARGS__) 1149 1150 /*MC 1151 PETSC_STATIC_ARRAY_LENGTH - Return the length of a static array 1152 1153 Synopsis: 1154 #include <petscmacros.h> 1155 size_t PETSC_STATIC_ARRAY_LENGTH(a) 1156 1157 Input Parameter: 1158 . a - a static array of any type 1159 1160 Output Parameter: 1161 . <return-value> - the length of the array 1162 1163 Example: 1164 .vb 1165 PetscInt a[22]; 1166 size_t sa = PETSC_STATIC_ARRAY_LENGTH(a) 1167 .ve 1168 `sa` will have a value of 22 1169 1170 Level: intermediate 1171 M*/ 1172 #define PETSC_STATIC_ARRAY_LENGTH(a) (sizeof(a) / sizeof((a)[0])) 1173 1174 /* 1175 These macros allow extracting out the first argument or all but the first argument from a macro __VAR_ARGS__ INSIDE another macro. 1176 1177 Example usage: 1178 1179 #define mymacro(obj,...) { 1180 PETSC_FIRST_ARG((__VA_ARGS__,unused)); 1181 f(22 PETSC_REST_ARG(__VA_ARGS__)); 1182 } 1183 1184 Note you add a dummy extra argument to __VA_ARGS__ and enclose them in an extra set of () for PETSC_FIRST_ARG() and PETSC_REST_ARG(__VA_ARGS__) automatically adds a leading comma only if there are additional arguments 1185 1186 Reference: 1187 https://stackoverflow.com/questions/5588855/standard-alternative-to-gccs-va-args-trick 1188 */ 1189 #define PETSC_FIRST_ARG_(N, ...) N 1190 #define PETSC_FIRST_ARG(args) PETSC_FIRST_ARG_ args 1191 #define PETSC_SELECT_16TH(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, ...) a16 1192 #define PETSC_NUM(...) PETSC_SELECT_16TH(__VA_ARGS__, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, ONE, throwaway) 1193 #define PETSC_REST_HELPER_TWOORMORE(first, ...) , __VA_ARGS__ 1194 #define PETSC_REST_HELPER_ONE(first) 1195 #define PETSC_REST_HELPER2(qty, ...) PETSC_REST_HELPER_##qty(__VA_ARGS__) 1196 #define PETSC_REST_HELPER(qty, ...) PETSC_REST_HELPER2(qty, __VA_ARGS__) 1197 #define PETSC_REST_ARG(...) PETSC_REST_HELPER(PETSC_NUM(__VA_ARGS__), __VA_ARGS__) 1198 1199 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(name, ...) \ 1200 _Pragma(PetscStringize(name diagnostic push)) \ 1201 _Pragma(PetscStringize(name diagnostic ignored __VA_ARGS__)) 1202 1203 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(name) _Pragma(PetscStringize(name diagnostic pop)) 1204 1205 #if defined(__clang__) 1206 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(clang, __VA_ARGS__) 1207 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END() PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(clang) 1208 #elif defined(__GNUC__) || defined(__GNUG__) 1209 // gcc >= 4.6.0 1210 #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) >= 40600 1211 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(GCC, __VA_ARGS__) 1212 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END() PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(GCC) 1213 #endif 1214 #endif 1215 1216 #ifndef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN 1217 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) 1218 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END(...) 1219 // only undefine these if they are not used 1220 #undef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_ 1221 #undef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_ 1222 #endif 1223 1224 /* OpenMP support */ 1225 #if defined(_OPENMP) 1226 #if defined(_MSC_VER) 1227 #define PetscPragmaOMP(...) __pragma(__VA_ARGS__) 1228 #else 1229 #define PetscPragmaOMP(...) _Pragma(PetscStringize(omp __VA_ARGS__)) 1230 #endif 1231 #endif 1232 1233 #ifndef PetscPragmaOMP 1234 #define PetscPragmaOMP(...) 1235 #endif 1236 1237 /* PetscPragmaSIMD - from CeedPragmaSIMD */ 1238 #if defined(__NEC__) 1239 #define PetscPragmaSIMD _Pragma("_NEC ivdep") 1240 #elif defined(__INTEL_COMPILER) && !defined(_WIN32) 1241 #define PetscPragmaSIMD _Pragma("vector") 1242 #elif defined(__GNUC__) 1243 #if __GNUC__ >= 5 && !defined(__PGI) 1244 #define PetscPragmaSIMD _Pragma("GCC ivdep") 1245 #endif 1246 #elif defined(_OPENMP) && _OPENMP >= 201307 1247 #define PetscPragmaSIMD PetscPragmaOMP(simd) 1248 #elif defined(PETSC_HAVE_CRAY_VECTOR) 1249 #define PetscPragmaSIMD _Pragma("_CRI ivdep") 1250 #endif 1251 1252 #ifndef PetscPragmaSIMD 1253 #define PetscPragmaSIMD 1254 #endif 1255 1256 #endif /* PETSC_PREPROCESSOR_MACROS_H */ 1257