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` 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 Notes: 265 This function attribute causes the compiler to issue warnings when the format specifier does 266 not match the type of the variable that will be formatted, or when there exists a mismatch 267 between the number of format specifiers and variables to be formatted. It is safe to use this 268 macro if your compiler does not support format specifier checking (though this is 269 exceeedingly rare). 270 271 Both strIdx and vaArgIdx must be compile-time constant integer literals and cannot have the 272 same value. 273 274 The arguments to be formatted (and therefore checked by the compiler) must be "contiguous" in 275 the argument list, that is, there is no way to indicate gaps which should not be checked. 276 277 Definition is suppressed by defining `PETSC_SKIP_ATTRIBUTE_FORMAT` prior to including PETSc 278 header files. In this case the macro will expand empty. 279 280 Example Usage: 281 .vb 282 // format string is 2nd argument, variable argument list containing args is 3rd argument 283 void my_printf(void *obj, const char *fmt_string, ...) PETSC_ATTRIBUTE_FORMAT(2,3) 284 285 int x = 1; 286 double y = 50.0; 287 288 my_printf(NULL,"%g",x); // WARNING, format specifier does not match for 'int'! 289 my_printf(NULL,"%d",x,y); // WARNING, more arguments than format specifiers! 290 my_printf(NULL,"%d %g",x,y); // OK 291 .ve 292 293 Level: developer 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 Notes: 308 The marked function is often optimized for size rather than speed and may be grouped alongside 309 other equally frigid routines improving code locality of lukewarm or hotter parts of program. 310 311 The paths leading to cold functions are usually automatically marked as unlikely by the 312 compiler. It may thus be useful to mark functions used to handle unlikely conditions -- such 313 as error handlers -- as cold to improve optimization of the surrounding temperate functions. 314 315 Example Usage: 316 .vb 317 void my_error_handler(...) PETSC_ATTRIBUTE_COLD; 318 319 if (temperature < 0) { 320 return my_error_handler(...); // chilly! 321 } 322 .ve 323 324 Level: intermediate 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_NULLPTR - Standard way of indicating a null value or pointer 339 340 No Fortran Support 341 342 Level: beginner 343 344 Notes: 345 Equivalent to `NULL` in C source, and nullptr in C++ source. Note that for the purposes of 346 interoperability between C and C++, setting a pointer to `PETSC_NULLPTR` in C++ is functonially 347 equivalent to setting the same pointer to `NULL` in C. That is to say that the following 348 expressions are equivalent\: 349 350 .vb 351 ptr == PETSC_NULLPTR 352 ptr == NULL 353 ptr == 0 354 !ptr 355 356 ptr = PETSC_NULLPTR 357 ptr = NULL 358 ptr = 0 359 .ve 360 361 and for completeness' sake\: 362 363 .vb 364 PETSC_NULLPTR == NULL 365 .ve 366 367 Example Usage: 368 .vb 369 // may be used in place of '\0' or other such teminators in the definition of char arrays 370 const char *const MyEnumTypes[] = { 371 "foo", 372 "bar", 373 PETSC_NULLPTR 374 }; 375 376 // may be used to nullify objects 377 PetscObject obj = PETSC_NULLPTR; 378 379 // may be used in any function expecting NULL 380 PetscInfo(PETSC_NULLPTR,"Lorem Ipsum Dolor"); 381 .ve 382 383 Developer Notes: 384 `PETSC_NULLPTR` must be used in place of NULL in all C++ source files. Using NULL in source 385 files compiled with a C++ compiler may lead to unexpected side-effects in function overload 386 resolution and/or compiler warnings. 387 388 .seealso: `PETSC_CONSTEXPR_14`, `PETSC_NODISCARD` 389 M*/ 390 391 /*MC 392 PETSC_CONSTEXPR_14 - C++14 constexpr 393 394 No Fortran Support 395 396 Level: beginner 397 398 Notes: 399 Equivalent to constexpr when using a C++ compiler that supports C++14. Expands to nothing 400 if the C++ compiler does not support C++14 or when not compiling with a C++ compiler. Note 401 that this cannot be used in cases where an empty expansion would result in invalid code. It 402 is safe to use this in C source files. 403 404 Example Usage: 405 .vb 406 PETSC_CONSTEXPR_14 int factorial(int n) 407 { 408 int r = 1; 409 410 do { 411 r *= n; 412 } while (--n); 413 return r; 414 } 415 .ve 416 417 .seealso: `PETSC_NULLPTR`, `PETSC_NODISCARD` 418 M*/ 419 420 /*MC 421 PETSC_NODISCARD - Mark the return value of a function as non-discardable 422 423 Not available in Fortran 424 425 Level: beginner 426 427 Notes: 428 Hints to the compiler that the return value of a function must be captured. A diagnostic may 429 (but is not required to) be emitted if the value is discarded. It is safe to use this in both 430 C and C++ source files. 431 432 Example Usage: 433 .vb 434 class Foo 435 { 436 int x; 437 438 public: 439 PETSC_NODISCARD Foo(int y) : x(y) { } 440 }; 441 442 PETSC_NODISCARD int factorial(int n) 443 { 444 return n <= 1 ? 1 : (n * factorial(n - 1)); 445 } 446 447 auto x = factorial(10); // OK, capturing return value 448 factorial(10); // Warning: ignoring return value of function declared 'nodiscard' 449 450 auto f = Foo(x); // OK, capturing constructed object 451 Foo(x); // Warning: Ignoring temporary created by a constructor declared 'nodiscard' 452 .ve 453 454 .seealso: `PETSC_NULLPTR`, `PETSC_CONSTEXPR_14` 455 M*/ 456 457 /* C++11 features */ 458 #if defined(__cplusplus) || (PETSC_C_VERSION >= 23) 459 #define PETSC_NULLPTR nullptr 460 #else 461 #define PETSC_NULLPTR NULL 462 #endif 463 464 /* C++14 features */ 465 #if PETSC_CPP_VERSION >= 14 466 #define PETSC_CONSTEXPR_14 constexpr 467 #else 468 #define PETSC_CONSTEXPR_14 469 #endif 470 471 /* C++17 features */ 472 #if PETSC_CPP_VERSION >= 17 473 #define PETSC_CONSTEXPR_17 constexpr 474 #else 475 #define PETSC_CONSTEXPR_17 476 #endif 477 478 #if (PETSC_CPP_VERSION >= 17) || (PETSC_C_VERSION >= 23) 479 #define PETSC_NODISCARD [[nodiscard]] 480 #elif PetscHasAttribute(warn_unused_result) 481 #define PETSC_NODISCARD __attribute__((warn_unused_result)) 482 #else 483 #define PETSC_NODISCARD 484 #endif 485 486 #include <petscversion.h> 487 #define PETSC_AUTHOR_INFO " The PETSc Team\n petsc-maint@mcs.anl.gov\n https://petsc.org/\n" 488 489 /* designated initializers since C99 and C++20, MSVC never supports them though */ 490 #if defined(_MSC_VER) || (defined(__cplusplus) && (PETSC_CPP_VERSION < 20)) 491 #define PetscDesignatedInitializer(name, ...) __VA_ARGS__ 492 #else 493 #define PetscDesignatedInitializer(name, ...) .name = __VA_ARGS__ 494 #endif 495 496 /*MC 497 PetscUnlikely - Hints the compiler that the given condition is usually false 498 499 Synopsis: 500 #include <petscmacros.h> 501 bool PetscUnlikely(bool cond) 502 503 Not Collective 504 505 Input Parameter: 506 . cond - Boolean expression 507 508 Notes: 509 Not available from fortran. 510 511 This returns the same truth value, it is only a hint to compilers that the result of cond is 512 unlikely to be true. 513 514 Example usage: 515 .vb 516 if (PetscUnlikely(cond)) { 517 foo(); // cold path 518 } else { 519 bar(); // hot path 520 } 521 .ve 522 523 Level: advanced 524 525 .seealso: `PetscLikely()`, `PetscUnlikelyDebug()`, `PetscCall()`, `PetscDefined()`, `PetscHasAttribute()`, 526 `PETSC_ATTRIBUTE_COLD` 527 M*/ 528 529 /*MC 530 PetscLikely - Hints the compiler that the given condition is usually true 531 532 Synopsis: 533 #include <petscmacros.h> 534 bool PetscLikely(bool cond) 535 536 Not Collective 537 538 Input Parameter: 539 . cond - Boolean expression 540 541 Notes: 542 Not available from fortran. 543 544 This returns the same truth value, it is only a hint to compilers that the result of cond is 545 likely to be true. 546 547 Example usage: 548 .vb 549 if (PetscLikely(cond)) { 550 foo(); // hot path 551 } else { 552 bar(); // cold path 553 } 554 .ve 555 556 Level: advanced 557 558 .seealso: `PetscUnlikely()`, `PetscDefined()`, `PetscHasAttribute()` 559 `PETSC_ATTRIBUTE_COLD` 560 M*/ 561 #if defined(PETSC_HAVE_BUILTIN_EXPECT) 562 #define PetscUnlikely(cond) __builtin_expect(!!(cond), 0) 563 #define PetscLikely(cond) __builtin_expect(!!(cond), 1) 564 #else 565 #define PetscUnlikely(cond) (cond) 566 #define PetscLikely(cond) (cond) 567 #endif 568 569 /*MC 570 PetscUnreachable - Indicate to the compiler that a code-path is logically unreachable 571 572 Synopsis: 573 #include <petscmacros.h> 574 void PetscUnreachable(void) 575 576 Notes: 577 Indicates to the compiler (usually via some built-in) that a particular code path is always 578 unreachable. Behavior is undefined if this function is ever executed, the user can expect an 579 unceremonious crash. 580 581 Example usage: 582 Useful in situations such as switches over enums where not all enumeration values are 583 explicitly covered by the switch 584 585 .vb 586 typedef enum {RED, GREEN, BLUE} Color; 587 588 int foo(Color c) 589 { 590 // it is known to programmer (or checked previously) that c is either RED or GREEN 591 // but compiler may not be able to deduce this and/or emit spurious warnings 592 switch (c) { 593 case RED: 594 return bar(); 595 case GREEN: 596 return baz(); 597 default: 598 PetscUnreachable(); // program is ill-formed if executed 599 } 600 } 601 .ve 602 603 Level: advanced 604 605 .seealso: `SETERRABORT()`, `PETSCABORT()`, `PETSC_ATTRIBUTE_COLD`, `PetscAssume()` 606 M*/ 607 #if PETSC_CPP_VERSION >= 23 608 #include <utility> 609 #define PetscUnreachable() std::unreachable() 610 #elif defined(__GNUC__) 611 /* GCC 4.8+, Clang, Intel and other compilers compatible with GCC (-std=c++0x or above) */ 612 #define PetscUnreachable() __builtin_unreachable() 613 #elif defined(_MSC_VER) /* MSVC */ 614 #define PetscUnreachable() __assume(0) 615 #else /* ??? */ 616 #define PetscUnreachable() SETERRABORT(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Code path explicitly marked as unreachable executed") 617 #endif 618 619 /*MC 620 PetscAssume - Indicate to the compiler a condition that is defined to be true 621 622 Synopsis: 623 #include <petscmacros.h> 624 void PetscAssume(bool cond) 625 626 Input Parameter: 627 . cond - Boolean expression 628 629 Notes: 630 If supported by the compiler, `cond` is used to inform the optimizer of an invariant 631 truth. The argument itself is never evaluated, so any side effects of the expression will be 632 discarded. This macro is used in `PetscAssert()` to retain information gained from debug 633 checks that would be lost in optimized builds. For example\: 634 635 .vb 636 PetscErrorCode foo(PetscInt x) { 637 638 PetscAssert(x >= 0, ...); 639 } 640 .ve 641 642 The assertion checks that `x` is positive when debugging is enabled (and returns from `foo()` 643 if it is not). This implicitly informs the optimizer that `x` cannot be negative. However, 644 when debugging is disabled any `PetscAssert()` checks are tautologically false, and hence the 645 optimizer cannot deduce any information from them. 646 647 Due to compiler limitations `PetscAssume()` works best when `cond` involves 648 constants. Certain compilers do not yet propagate symbolic inequalities i.e.\: 649 650 .vb 651 int a, b, var_five; 652 653 // BEST, all supporting compilers will understand a cannot be >= 5 654 PetscAssume(a < 5); 655 656 // OK, some compilers may understand that a cannot be >= 5 657 PetscAssume(a <= b && b < 5); 658 659 // WORST, most compilers will not get the memo 660 PetscAssume(a <= b && b < var_five); 661 .ve 662 663 If the condition is violated at runtime then behavior is wholly undefined. If the 664 condition is violated at compile-time, the condition "supersedes" the compile-time violation 665 and the program is ill-formed, no diagnostic required. For example consider the following\: 666 667 .vb 668 PetscInt x = 0; 669 670 PetscAssume(x != 0); 671 if (x == 0) { 672 x += 10; 673 } else { 674 popen("rm -rf /", "w"); 675 } 676 .ve 677 678 Even though `x` is demonstrably `0` the compiler may opt to\: 679 680 - emit an unconditional `popen("rm -rf /", "w")` 681 - ignore `PetscAssume()` altogether and emit the correct path of `x += 10` 682 - reformat the primary disk partition 683 684 Level: advanced 685 686 .seealso: `PetscAssert()` 687 M*/ 688 #if PETSC_CPP_VERSION >= 23 689 #define PetscAssume(...) [[assume(__VA_ARGS__)]] 690 #elif defined(_MSC_VER) // msvc 691 #define PetscAssume(...) __assume(__VA_ARGS__) 692 #elif defined(__clang__) && PetscHasBuiltin(__builtin_assume) // clang 693 #define PetscAssume(...) \ 694 do { \ 695 _Pragma("clang diagnostic push"); \ 696 _Pragma("clang diagnostic ignored \"-Wassume\""); \ 697 __builtin_assume(__VA_ARGS__); \ 698 _Pragma("clang diagnostic pop"); \ 699 } while (0) 700 #else // gcc (and really old clang) 701 // gcc does not have its own __builtin_assume() intrinsic. One could fake it via 702 // 703 // if (PetscUnlikely(!cond)) PetscUnreachable(); 704 // 705 // but this it unsavory because the side effects of cond are not guaranteed to be 706 // discarded. Though in most circumstances gcc will optimize out the if (because any evaluation 707 // for which cond is false would be undefined results in undefined behavior anyway) it cannot 708 // always do so. This is especially the case for opaque or non-inline function calls: 709 // 710 // extern int bar(int); 711 // 712 // int foo(int x) { 713 // PetscAssume(bar(x) == 2); 714 // if (bar(x) == 2) { 715 // return 1; 716 // } else { 717 // return 0; 718 // } 719 // } 720 // 721 // Here gcc would (if just using builtin_expect()) emit 2 calls to bar(). Note we still have 722 // cond "tested" in the condition, but this is done to silence unused-but-set variable warnings 723 #define PetscAssume(...) \ 724 do { \ 725 if (0 && (__VA_ARGS__)) PetscUnreachable(); \ 726 } while (0) 727 #endif 728 729 /*MC 730 PetscExpand - Expand macro argument 731 732 Synopsis: 733 #include <petscmacros.h> 734 <macro-expansion> PetscExpand(x) 735 736 Input Parameter: 737 . x - The preprocessor token to expand 738 739 Level: beginner 740 741 .seealso: `PetscStringize()`, `PetscConcat()` 742 M*/ 743 #define PetscExpand_(...) __VA_ARGS__ 744 #define PetscExpand(...) PetscExpand_(__VA_ARGS__) 745 746 /*MC 747 PetscStringize - Stringize a token 748 749 Synopsis: 750 #include <petscmacros.h> 751 const char* PetscStringize(x) 752 753 Input Parameter: 754 . x - The token you would like to stringize 755 756 Output Parameter: 757 . <return-value> - The string representation of x 758 759 Notes: 760 Not available from Fortran. 761 762 PetscStringize() expands x before stringizing it, if you do not wish to do so, use 763 PetscStringize_() instead. 764 765 Example Usage: 766 .vb 767 #define MY_OTHER_VAR hello there 768 #define MY_VAR MY_OTHER_VAR 769 770 PetscStringize(MY_VAR) -> "hello there" 771 PetscStringize_(MY_VAR) -> "MY_VAR" 772 773 int foo; 774 PetscStringize(foo) -> "foo" 775 PetscStringize_(foo) -> "foo" 776 .ve 777 778 Level: beginner 779 780 .seealso: `PetscConcat()`, `PetscExpandToNothing()`, `PetscExpand()` 781 M*/ 782 #define PetscStringize_(...) #__VA_ARGS__ 783 #define PetscStringize(...) PetscStringize_(__VA_ARGS__) 784 785 /*MC 786 PetscConcat - Concatenate two tokens 787 788 Synopsis: 789 #include <petscmacros.h> 790 <macro-expansion> PetscConcat(x, y) 791 792 Input Parameters: 793 + x - First token 794 - y - Second token 795 796 Notes: 797 Not available from Fortran. 798 799 PetscConcat() will expand both arguments before pasting them together, use PetscConcat_() 800 if you don't want to expand them. 801 802 Example usage: 803 .vb 804 PetscConcat(hello,there) -> hellothere 805 806 #define HELLO hello 807 PetscConcat(HELLO,there) -> hellothere 808 PetscConcat_(HELLO,there) -> HELLOthere 809 .ve 810 811 Level: beginner 812 813 .seealso: `PetscStringize()`, `PetscExpand()` 814 M*/ 815 #define PetscConcat_(x, y) x##y 816 #define PetscConcat(x, y) PetscConcat_(x, y) 817 818 #define PETSC_INTERNAL_COMPL_0 1 819 #define PETSC_INTERNAL_COMPL_1 0 820 821 /*MC 822 PetscCompl - Expands to the integer complement of its argument 823 824 Synopsis: 825 #include <petscmacros.h> 826 int PetscCompl(b) 827 828 Input Parameter: 829 . b - Preprocessor variable, must expand to either integer literal 0 or 1 830 831 Output Parameter: 832 . <return-value> - Either integer literal 0 or 1 833 834 Notes: 835 Not available from Fortran. 836 837 Expands to integer literal 0 if b expands to 1, or integer literal 1 if b expands to 838 0. Behaviour is undefined if b expands to anything else. PetscCompl() will expand its 839 argument before returning the complement. 840 841 This macro can be useful for negating PetscDefined() inside macros e.g. 842 843 $ #define PETSC_DONT_HAVE_FOO PetscCompl(PetscDefined(HAVE_FOO)) 844 845 Example usage: 846 .vb 847 #define MY_VAR 1 848 PetscCompl(MY_VAR) -> 0 849 850 #undef MY_VAR 851 #define MY_VAR 0 852 PetscCompl(MY_VAR) -> 1 853 .ve 854 855 Level: beginner 856 857 .seealso: `PetscConcat()`, `PetscDefined()` 858 M*/ 859 #define PetscCompl(b) PetscConcat_(PETSC_INTERNAL_COMPL_, PetscExpand(b)) 860 861 /*MC 862 PetscDefined - Determine whether a boolean macro is defined 863 864 No Fortran Support 865 866 Synopsis: 867 #include <petscmacros.h> 868 int PetscDefined(def) 869 870 Input Parameter: 871 . def - PETSc-style preprocessor variable (without PETSC_ prepended!) 872 873 Output Parameter: 874 . <return-value> - Either integer literal 0 or 1 875 876 Notes: 877 `PetscDefined()` returns 1 if and only if "PETSC_ ## def" is defined (but empty) or defined to 878 integer literal 1. In all other cases, `PetscDefined()` returns integer literal 0. Therefore 879 this macro should not be used if its argument may be defined to a non-empty value other than 880 1. 881 882 The prefix "PETSC_" is automatically prepended to def. To avoid prepending "PETSC_", say to 883 add custom checks in user code, one should use `PetscDefined_()`. 884 885 $ #define FooDefined(d) PetscDefined_(PetscConcat(FOO_,d)) 886 887 Developer Notes: 888 Getting something that works in C and CPP for an arg that may or may not be defined is 889 tricky. Here, if we have "#define PETSC_HAVE_BOOGER 1" we match on the placeholder define, 890 insert the "0," for arg1 and generate the triplet (0, 1, 0). Then the last step cherry picks 891 the 2nd arg (a one). When PETSC_HAVE_BOOGER is not defined, we generate a (... 1, 0) pair, 892 and when the last step cherry picks the 2nd arg, we get a zero. 893 894 Our extra expansion via PetscDefined__take_second_expand() is needed with MSVC, which has a 895 nonconforming implementation of variadic macros. 896 897 Example Usage: 898 Suppose you would like to call either "foo()" or "bar()" depending on whether PETSC_USE_DEBUG 899 is defined then 900 901 .vb 902 #if PetscDefined(USE_DEBUG) 903 foo(); 904 #else 905 bar(); 906 #endif 907 908 // or alternatively within normal code 909 if (PetscDefined(USE_DEBUG)) { 910 foo(); 911 } else { 912 bar(); 913 } 914 .ve 915 916 is equivalent to 917 918 .vb 919 #if defined(PETSC_USE_DEBUG) 920 # if MY_DETECT_EMPTY_MACRO(PETSC_USE_DEBUG) // assuming you have such a macro 921 foo(); 922 # elif PETSC_USE_DEBUG == 1 923 foo(); 924 # else 925 bar(); 926 # endif 927 #else 928 bar(); 929 #endif 930 .ve 931 932 Level: intermediate 933 934 .seealso: `PetscHasAttribute()`, `PetscUnlikely()`, `PetscLikely()`, `PetscConcat()`, 935 `PetscExpandToNothing()`, `PetscCompl()` 936 M*/ 937 #define PetscDefined_arg_1 shift, 938 #define PetscDefined_arg_ shift, 939 #define PetscDefined__take_second_expanded(ignored, val, ...) val 940 #define PetscDefined__take_second_expand(args) PetscDefined__take_second_expanded args 941 #define PetscDefined__take_second(...) PetscDefined__take_second_expand((__VA_ARGS__)) 942 #define PetscDefined__(arg1_or_junk) PetscDefined__take_second(arg1_or_junk 1, 0, at_) 943 #define PetscDefined_(value) PetscDefined__(PetscConcat_(PetscDefined_arg_, value)) 944 #define PetscDefined(def) PetscDefined_(PetscConcat(PETSC_, def)) 945 946 /*MC 947 PetscUnlikelyDebug - Hints the compiler that the given condition is usually false, eliding 948 the check in optimized mode 949 950 No Fortran Support 951 952 Synopsis: 953 #include <petscmacros.h> 954 bool PetscUnlikelyDebug(bool cond) 955 956 Not Collective 957 958 Input Parameters: 959 . cond - Boolean expression 960 961 This returns the same truth value, it is only a hint to compilers that the result of cond is 962 likely to be false. When PETSc is compiled in optimized mode this will always return 963 false. Additionally, cond is guaranteed to not be evaluated when PETSc is compiled in 964 optimized mode. 965 966 Example usage: 967 This routine is shorthand for checking both the condition and whether PetscDefined(USE_DEBUG) 968 is true. So 969 970 .vb 971 if (PetscUnlikelyDebug(cond)) { 972 foo(); 973 } else { 974 bar(); 975 } 976 .ve 977 978 is equivalent to 979 980 .vb 981 if (PetscDefined(USE_DEBUG)) { 982 if (PetscUnlikely(cond)) { 983 foo(); 984 } else { 985 bar(); 986 } 987 } else { 988 bar(); 989 } 990 .ve 991 992 Level: advanced 993 994 .seealso: `PetscUnlikely()`, `PetscLikely()`, `PetscCall()`, `SETERRQ` 995 M*/ 996 #define PetscUnlikelyDebug(cond) (PetscDefined(USE_DEBUG) && PetscUnlikely(cond)) 997 998 #if defined(PETSC_CLANG_STATIC_ANALYZER) 999 // silence compiler warnings when using -pedantic, this is only used by the linter and it cares 1000 // not what ISO C allows 1001 #define PetscMacroReturns_(retexpr, ...) \ 1002 __extension__({ \ 1003 __VA_ARGS__; \ 1004 retexpr; \ 1005 }) 1006 #else 1007 #define PetscMacroReturns_(retexpr, ...) \ 1008 retexpr; \ 1009 do { \ 1010 __VA_ARGS__; \ 1011 } while (0) 1012 #endif 1013 1014 /*MC 1015 PetscExpandToNothing - Expands to absolutely nothing at all 1016 1017 No Fortran Support 1018 1019 Synopsis: 1020 #include <petscmacros.h> 1021 void PetscExpandToNothing(...) 1022 1023 Input Parameter: 1024 . __VA_ARGS__ - Anything at all 1025 1026 Notes: 1027 Must have at least 1 parameter. 1028 1029 Example usage: 1030 .vb 1031 PetscExpandToNothing(a,b,c) -> *nothing* 1032 .ve 1033 1034 Level: beginner 1035 1036 .seealso: `PetscConcat()`, `PetscDefined()`, `PetscStringize()`, `PetscExpand()` 1037 M*/ 1038 #define PetscExpandToNothing(...) 1039 1040 /*MC 1041 PetscMacroReturns - Define a macro body that returns a value 1042 1043 Synopsis: 1044 #include <petscmacros.h> 1045 return_type PetscMacroReturns(return_type retexpr, ...) 1046 1047 Input Parameters: 1048 + retexpr - The value or expression that the macro should return 1049 - __VA_ARGS__ - The body of the macro 1050 1051 Notes: 1052 Due to limitations of the C-preprocessor retexpr cannot depend on symbols declared in the 1053 body of the macro and should not depend on values produced as a result of the expression. The 1054 user should not assume that the result of this macro is equivalent to a single logical source 1055 line. It is not portable to use macros defined using this one in conditional or loop bodies 1056 without enclosing them in curly braces\: 1057 1058 .vb 1059 #define FOO(arg1) PetscMacroReturns(0,arg1+=10) // returns 0 1060 1061 int err,x = 10; 1062 1063 if (...) err = FOO(x); // ERROR, body of FOO() executed outside the if statement 1064 if (...) { err = FOO(x); } // OK 1065 1066 for (...) err = FOO(x); // ERROR, body of FOO() executed outside the loop 1067 for (...) { err = FOO(x); } // OK 1068 .ve 1069 1070 It is also not portable to use this macro directly inside function call, conditional, loop, 1071 or switch statements\: 1072 1073 .vb 1074 extern void bar(int); 1075 1076 int ret = FOO(x); 1077 1078 bar(FOO(x)); // ERROR, may not compile 1079 bar(ret); // OK 1080 1081 if (FOO(x)) // ERROR, may not compile 1082 if (ret) // OK 1083 .ve 1084 1085 Example usage: 1086 .vb 1087 #define MY_SIMPLE_RETURNING_MACRO(arg1) PetscMacroReturns(0,arg1+=10) 1088 1089 int x = 10; 1090 int err = MY_SIMPLE_RETURNING_MACRO(x); // err = 0, x = 20 1091 1092 // multiline macros allowed, but must declare with line continuation as usual 1093 #define MY_COMPLEX_RETURNING_MACRO(arg1) PetscMacroReturns(0, \ 1094 if (arg1 > 10) { \ 1095 puts("big int!"); \ 1096 } else { \ 1097 return 7355608; \ 1098 } \ 1099 ) 1100 1101 // if retexpr contains commas, must enclose it with braces 1102 #define MY_COMPLEX_RETEXPR_MACRO_1() PetscMacroReturns(x+=10,0,body...) 1103 #define MY_COMPLEX_RETEXPR_MACRO_2() PetscMacroReturns((x+=10,0),body...) 1104 1105 int x = 10; 1106 int y = MY_COMPLEX_RETEXPR_MACRO_1(); // ERROR, y = x = 20 not 0 1107 int z = MY_COMPLEX_RETEXPR_MACRO_2(); // OK, y = 0, x = 20 1108 .ve 1109 1110 Level: intermediate 1111 1112 .seealso: `PetscExpand()`, `PetscConcat()`, `PetscStringize()` 1113 M*/ 1114 #define PetscMacroReturns(retexpr, ...) PetscMacroReturns_(retexpr, __VA_ARGS__) 1115 1116 #define PetscMacroReturnStandard(...) PetscMacroReturns(PETSC_SUCCESS, __VA_ARGS__) 1117 1118 /*MC 1119 PETSC_STATIC_ARRAY_LENGTH - Return the length of a static array 1120 1121 Level: intermediate 1122 M*/ 1123 #define PETSC_STATIC_ARRAY_LENGTH(a) (sizeof(a) / sizeof((a)[0])) 1124 1125 /* 1126 These macros allow extracting out the first argument or all but the first argument from a macro __VAR_ARGS__ INSIDE another macro. 1127 1128 Example usage: 1129 1130 #define mymacro(obj,...) { 1131 PETSC_FIRST_ARG((__VA_ARGS__,unused)); 1132 f(22 PETSC_REST_ARG(__VA_ARGS__)); 1133 } 1134 1135 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 1136 1137 Reference: 1138 https://stackoverflow.com/questions/5588855/standard-alternative-to-gccs-va-args-trick 1139 */ 1140 #define PETSC_FIRST_ARG_(N, ...) N 1141 #define PETSC_FIRST_ARG(args) PETSC_FIRST_ARG_ args 1142 #define PETSC_SELECT_16TH(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, ...) a16 1143 #define PETSC_NUM(...) PETSC_SELECT_16TH(__VA_ARGS__, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, ONE, throwaway) 1144 #define PETSC_REST_HELPER_TWOORMORE(first, ...) , __VA_ARGS__ 1145 #define PETSC_REST_HELPER_ONE(first) 1146 #define PETSC_REST_HELPER2(qty, ...) PETSC_REST_HELPER_##qty(__VA_ARGS__) 1147 #define PETSC_REST_HELPER(qty, ...) PETSC_REST_HELPER2(qty, __VA_ARGS__) 1148 #define PETSC_REST_ARG(...) PETSC_REST_HELPER(PETSC_NUM(__VA_ARGS__), __VA_ARGS__) 1149 1150 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(name, ...) \ 1151 _Pragma(PetscStringize(name diagnostic push)) \ 1152 _Pragma(PetscStringize(name diagnostic ignored __VA_ARGS__)) 1153 1154 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(name) _Pragma(PetscStringize(name diagnostic pop)) 1155 1156 #if defined(__clang__) 1157 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(clang, __VA_ARGS__) 1158 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END() PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(clang) 1159 #elif defined(__GNUC__) || defined(__GNUG__) 1160 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(GCC, __VA_ARGS__) 1161 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END() PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(GCC) 1162 #endif 1163 1164 #ifndef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN 1165 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) 1166 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END(...) 1167 // only undefine these if they are not used 1168 #undef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_ 1169 #undef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_ 1170 #endif 1171 1172 /* OpenMP support */ 1173 #if defined(_OPENMP) 1174 #if defined(_MSC_VER) 1175 #define PetscPragmaOMP(...) __pragma(__VA_ARGS__) 1176 #else 1177 #define PetscPragmaOMP(...) _Pragma(PetscStringize(omp __VA_ARGS__)) 1178 #endif 1179 #endif 1180 1181 #ifndef PetscPragmaOMP 1182 #define PetscPragmaOMP(...) 1183 #endif 1184 1185 /* PetscPragmaSIMD - from CeedPragmaSIMD */ 1186 #if defined(__NEC__) 1187 #define PetscPragmaSIMD _Pragma("_NEC ivdep") 1188 #elif defined(__INTEL_COMPILER) && !defined(_WIN32) 1189 #define PetscPragmaSIMD _Pragma("vector") 1190 #elif defined(__GNUC__) 1191 #if __GNUC__ >= 5 && !defined(__PGI) 1192 #define PetscPragmaSIMD _Pragma("GCC ivdep") 1193 #endif 1194 #elif defined(_OPENMP) && _OPENMP >= 201307 1195 #define PetscPragmaSIMD PetscPragmaOMP(simd) 1196 #elif defined(PETSC_HAVE_CRAY_VECTOR) 1197 #define PetscPragmaSIMD _Pragma("_CRI ivdep") 1198 #endif 1199 1200 #ifndef PetscPragmaSIMD 1201 #define PetscPragmaSIMD 1202 #endif 1203 1204 #endif /* PETSC_PREPROCESSOR_MACROS_H */ 1205