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 Notes: 341 Equivalent to NULL in C source, and nullptr in C++ source. Note that for the purposes of 342 interoperability between C and C++, setting a pointer to `PETSC_NULLPTR` in C++ is functonially 343 equivalent to setting the same pointer to NULL in C. That is to say that the following 344 expressions are equivalent\: 345 346 .vb 347 ptr == PETSC_NULLPTR 348 ptr == NULL 349 ptr == 0 350 !ptr 351 352 ptr = PETSC_NULLPTR 353 ptr = NULL 354 ptr = 0 355 .ve 356 357 and for completeness' sake\: 358 359 .vb 360 PETSC_NULLPTR == NULL 361 .ve 362 363 Fortran Notes: 364 Not available in Fortran 365 366 Example Usage: 367 .vb 368 // may be used in place of '\0' or other such teminators in the definition of char arrays 369 const char *const MyEnumTypes[] = { 370 "foo", 371 "bar", 372 PETSC_NULLPTR 373 }; 374 375 // may be used to nullify objects 376 PetscObject obj = PETSC_NULLPTR; 377 378 // may be used in any function expecting NULL 379 PetscInfo(PETSC_NULLPTR,"Lorem Ipsum Dolor"); 380 .ve 381 382 Developer Notes: 383 `PETSC_NULLPTR` must be used in place of NULL in all C++ source files. Using NULL in source 384 files compiled with a C++ compiler may lead to unexpected side-effects in function overload 385 resolution and/or compiler warnings. 386 387 Level: beginner 388 389 .seealso: `PETSC_CONSTEXPR_14`, `PETSC_NODISCARD` 390 M*/ 391 392 /*MC 393 PETSC_CONSTEXPR_14 - C++14 constexpr 394 395 Notes: 396 Equivalent to constexpr when using a C++ compiler that supports C++14. Expands to nothing 397 if the C++ compiler does not support C++14 or when not compiling with a C++ compiler. Note 398 that this cannot be used in cases where an empty expansion would result in invalid code. It 399 is safe to use this in C source files. 400 401 Fortran Notes: 402 Not available in Fortran 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 Level: beginner 418 419 .seealso: `PETSC_NULLPTR`, `PETSC_NODISCARD` 420 M*/ 421 422 /*MC 423 PETSC_NODISCARD - Mark the return value of a function as non-discardable 424 425 Not available in Fortran 426 427 Level: beginner 428 429 Notes: 430 Hints to the compiler that the return value of a function must be captured. A diagnostic may 431 (but is not required to) be emitted if the value is discarded. It is safe to use this in both 432 C and C++ source files. 433 434 Example Usage: 435 .vb 436 class Foo 437 { 438 int x; 439 440 public: 441 PETSC_NODISCARD Foo(int y) : x(y) { } 442 }; 443 444 PETSC_NODISCARD int factorial(int n) 445 { 446 return n <= 1 ? 1 : (n * factorial(n - 1)); 447 } 448 449 auto x = factorial(10); // OK, capturing return value 450 factorial(10); // Warning: ignoring return value of function declared 'nodiscard' 451 452 auto f = Foo(x); // OK, capturing constructed object 453 Foo(x); // Warning: Ignoring temporary created by a constructor declared 'nodiscard' 454 .ve 455 456 .seealso: `PETSC_NULLPTR`, `PETSC_CONSTEXPR_14` 457 M*/ 458 459 /* C++11 features */ 460 #if defined(__cplusplus) || (PETSC_C_VERSION >= 23) 461 #define PETSC_NULLPTR nullptr 462 #else 463 #define PETSC_NULLPTR NULL 464 #endif 465 466 /* C++14 features */ 467 #if PETSC_CPP_VERSION >= 14 468 #define PETSC_CONSTEXPR_14 constexpr 469 #else 470 #define PETSC_CONSTEXPR_14 471 #endif 472 473 /* C++17 features */ 474 #if PETSC_CPP_VERSION >= 17 475 #define PETSC_CONSTEXPR_17 constexpr 476 #else 477 #define PETSC_CONSTEXPR_17 478 #endif 479 480 #if (PETSC_CPP_VERSION >= 17) || (PETSC_C_VERSION >= 23) 481 #define PETSC_NODISCARD [[nodiscard]] 482 #elif PetscHasAttribute(warn_unused_result) 483 #define PETSC_NODISCARD __attribute__((warn_unused_result)) 484 #else 485 #define PETSC_NODISCARD 486 #endif 487 488 #include <petscversion.h> 489 #define PETSC_AUTHOR_INFO " The PETSc Team\n petsc-maint@mcs.anl.gov\n https://petsc.org/\n" 490 491 /* designated initializers since C99 and C++20, MSVC never supports them though */ 492 #if defined(_MSC_VER) || (defined(__cplusplus) && (PETSC_CPP_VERSION < 20)) 493 #define PetscDesignatedInitializer(name, ...) __VA_ARGS__ 494 #else 495 #define PetscDesignatedInitializer(name, ...) .name = __VA_ARGS__ 496 #endif 497 498 /*MC 499 PetscUnlikely - Hints the compiler that the given condition is usually false 500 501 Synopsis: 502 #include <petscmacros.h> 503 bool PetscUnlikely(bool cond) 504 505 Not Collective 506 507 Input Parameter: 508 . cond - Boolean expression 509 510 Notes: 511 Not available from fortran. 512 513 This returns the same truth value, it is only a hint to compilers that the result of cond is 514 unlikely to be true. 515 516 Example usage: 517 .vb 518 if (PetscUnlikely(cond)) { 519 foo(); // cold path 520 } else { 521 bar(); // hot path 522 } 523 .ve 524 525 Level: advanced 526 527 .seealso: `PetscLikely()`, `PetscUnlikelyDebug()`, `PetscCall()`, `PetscDefined()`, `PetscHasAttribute()`, 528 `PETSC_ATTRIBUTE_COLD` 529 M*/ 530 531 /*MC 532 PetscLikely - Hints the compiler that the given condition is usually true 533 534 Synopsis: 535 #include <petscmacros.h> 536 bool PetscLikely(bool cond) 537 538 Not Collective 539 540 Input Parameter: 541 . cond - Boolean expression 542 543 Notes: 544 Not available from fortran. 545 546 This returns the same truth value, it is only a hint to compilers that the result of cond is 547 likely to be true. 548 549 Example usage: 550 .vb 551 if (PetscLikely(cond)) { 552 foo(); // hot path 553 } else { 554 bar(); // cold path 555 } 556 .ve 557 558 Level: advanced 559 560 .seealso: `PetscUnlikely()`, `PetscDefined()`, `PetscHasAttribute()` 561 `PETSC_ATTRIBUTE_COLD` 562 M*/ 563 #if defined(PETSC_HAVE_BUILTIN_EXPECT) 564 #define PetscUnlikely(cond) __builtin_expect(!!(cond), 0) 565 #define PetscLikely(cond) __builtin_expect(!!(cond), 1) 566 #else 567 #define PetscUnlikely(cond) (cond) 568 #define PetscLikely(cond) (cond) 569 #endif 570 571 /*MC 572 PetscUnreachable - Indicate to the compiler that a code-path is logically unreachable 573 574 Synopsis: 575 #include <petscmacros.h> 576 void PetscUnreachable(void) 577 578 Notes: 579 Indicates to the compiler (usually via some built-in) that a particular code path is always 580 unreachable. Behavior is undefined if this function is ever executed, the user can expect an 581 unceremonious crash. 582 583 Example usage: 584 Useful in situations such as switches over enums where not all enumeration values are 585 explicitly covered by the switch 586 587 .vb 588 typedef enum {RED, GREEN, BLUE} Color; 589 590 int foo(Color c) 591 { 592 // it is known to programmer (or checked previously) that c is either RED or GREEN 593 // but compiler may not be able to deduce this and/or emit spurious warnings 594 switch (c) { 595 case RED: 596 return bar(); 597 case GREEN: 598 return baz(); 599 default: 600 PetscUnreachable(); // program is ill-formed if executed 601 } 602 } 603 .ve 604 605 Level: advanced 606 607 .seealso: `SETERRABORT()`, `PETSCABORT()`, `PETSC_ATTRIBUTE_COLD`, `PetscAssume()` 608 M*/ 609 #if PETSC_CPP_VERSION >= 23 610 #include <utility> 611 #define PetscUnreachable() std::unreachable() 612 #elif defined(__GNUC__) 613 /* GCC 4.8+, Clang, Intel and other compilers compatible with GCC (-std=c++0x or above) */ 614 #define PetscUnreachable() __builtin_unreachable() 615 #elif defined(_MSC_VER) /* MSVC */ 616 #define PetscUnreachable() __assume(0) 617 #else /* ??? */ 618 #define PetscUnreachable() SETERRABORT(PETSC_COMM_SELF, PETSC_ERR_PLIB, "Code path explicitly marked as unreachable executed") 619 #endif 620 621 /*MC 622 PetscAssume - Indicate to the compiler a condition that is defined to be true 623 624 Synopsis: 625 #include <petscmacros.h> 626 void PetscAssume(bool cond) 627 628 Input Parameter: 629 . cond - Boolean expression 630 631 Notes: 632 If supported by the compiler, `cond` is used to inform the optimizer of an invariant 633 truth. The argument itself is never evaluated, so any side effects of the expression will be 634 discarded. This macro is used in `PetscAssert()` to retain information gained from debug 635 checks that would be lost in optimized builds. For example\: 636 637 .vb 638 PetscErrorCode foo(PetscInt x) { 639 640 PetscAssert(x >= 0, ...); 641 } 642 .ve 643 644 The assertion checks that `x` is positive when debugging is enabled (and returns from `foo()` 645 if it is not). This implicitly informs the optimizer that `x` cannot be negative. However, 646 when debugging is disabled any `PetscAssert()` checks are tautologically false, and hence the 647 optimizer cannot deduce any information from them. 648 649 Due to compiler limitations `PetscAssume()` works best when `cond` involves 650 constants. Certain compilers do not yet propagate symbolic inequalities i.e.\: 651 652 .vb 653 int a, b, var_five; 654 655 // BEST, all supporting compilers will understand a cannot be >= 5 656 PetscAssume(a < 5); 657 658 // OK, some compilers may understand that a cannot be >= 5 659 PetscAssume(a <= b && b < 5); 660 661 // WORST, most compilers will not get the memo 662 PetscAssume(a <= b && b < var_five); 663 .ve 664 665 If the condition is violated at runtime then behavior is wholly undefined. If the 666 condition is violated at compile-time, the condition "supersedes" the compile-time violation 667 and the program is ill-formed, no diagnostic required. For example consider the following\: 668 669 .vb 670 PetscInt x = 0; 671 672 PetscAssume(x != 0); 673 if (x == 0) { 674 x += 10; 675 } else { 676 popen("rm -rf /", "w"); 677 } 678 .ve 679 680 Even though `x` is demonstrably `0` the compiler may opt to\: 681 682 - emit an unconditional `popen("rm -rf /", "w")` 683 - ignore `PetscAssume()` altogether and emit the correct path of `x += 10` 684 - reformat the primary disk partition 685 686 Level: advanced 687 688 .seealso: `PetscAssert()` 689 M*/ 690 #if PETSC_CPP_VERSION >= 23 691 #define PetscAssume(...) [[assume(__VA_ARGS__)]] 692 #elif defined(_MSC_VER) // msvc 693 #define PetscAssume(...) __assume(__VA_ARGS__) 694 #elif defined(__clang__) && PetscHasBuiltin(__builtin_assume) // clang 695 #define PetscAssume(...) \ 696 do { \ 697 _Pragma("clang diagnostic push"); \ 698 _Pragma("clang diagnostic ignored \"-Wassume\""); \ 699 __builtin_assume(__VA_ARGS__); \ 700 _Pragma("clang diagnostic pop"); \ 701 } while (0) 702 #else // gcc (and really old clang) 703 // gcc does not have its own __builtin_assume() intrinsic. One could fake it via 704 // 705 // if (PetscUnlikely(!cond)) PetscUnreachable(); 706 // 707 // but this it unsavory because the side effects of cond are not guaranteed to be 708 // discarded. Though in most circumstances gcc will optimize out the if (because any evaluation 709 // for which cond is false would be undefined results in undefined behavior anyway) it cannot 710 // always do so. This is especially the case for opaque or non-inline function calls: 711 // 712 // extern int bar(int); 713 // 714 // int foo(int x) { 715 // PetscAssume(bar(x) == 2); 716 // if (bar(x) == 2) { 717 // return 1; 718 // } else { 719 // return 0; 720 // } 721 // } 722 // 723 // Here gcc would (if just using builtin_expect()) emit 2 calls to bar(). Note we still have 724 // cond "tested" in the condition, but this is done to silence unused-but-set variable warnings 725 #define PetscAssume(...) \ 726 do { \ 727 if (0 && (__VA_ARGS__)) PetscUnreachable(); \ 728 } while (0) 729 #endif 730 731 /*MC 732 PetscExpand - Expand macro argument 733 734 Synopsis: 735 #include <petscmacros.h> 736 <macro-expansion> PetscExpand(x) 737 738 Input Parameter: 739 . x - The preprocessor token to expand 740 741 Level: beginner 742 743 .seealso: `PetscStringize()`, `PetscConcat()` 744 M*/ 745 #define PetscExpand_(...) __VA_ARGS__ 746 #define PetscExpand(...) PetscExpand_(__VA_ARGS__) 747 748 /*MC 749 PetscStringize - Stringize a token 750 751 Synopsis: 752 #include <petscmacros.h> 753 const char* PetscStringize(x) 754 755 Input Parameter: 756 . x - The token you would like to stringize 757 758 Output Parameter: 759 . <return-value> - The string representation of x 760 761 Notes: 762 Not available from Fortran. 763 764 PetscStringize() expands x before stringizing it, if you do not wish to do so, use 765 PetscStringize_() instead. 766 767 Example Usage: 768 .vb 769 #define MY_OTHER_VAR hello there 770 #define MY_VAR MY_OTHER_VAR 771 772 PetscStringize(MY_VAR) -> "hello there" 773 PetscStringize_(MY_VAR) -> "MY_VAR" 774 775 int foo; 776 PetscStringize(foo) -> "foo" 777 PetscStringize_(foo) -> "foo" 778 .ve 779 780 Level: beginner 781 782 .seealso: `PetscConcat()`, `PetscExpandToNothing()`, `PetscExpand()` 783 M*/ 784 #define PetscStringize_(...) #__VA_ARGS__ 785 #define PetscStringize(...) PetscStringize_(__VA_ARGS__) 786 787 /*MC 788 PetscConcat - Concatenate two tokens 789 790 Synopsis: 791 #include <petscmacros.h> 792 <macro-expansion> PetscConcat(x, y) 793 794 Input Parameters: 795 + x - First token 796 - y - Second token 797 798 Notes: 799 Not available from Fortran. 800 801 PetscConcat() will expand both arguments before pasting them together, use PetscConcat_() 802 if you don't want to expand them. 803 804 Example usage: 805 .vb 806 PetscConcat(hello,there) -> hellothere 807 808 #define HELLO hello 809 PetscConcat(HELLO,there) -> hellothere 810 PetscConcat_(HELLO,there) -> HELLOthere 811 .ve 812 813 Level: beginner 814 815 .seealso: `PetscStringize()`, `PetscExpand()` 816 M*/ 817 #define PetscConcat_(x, y) x##y 818 #define PetscConcat(x, y) PetscConcat_(x, y) 819 820 #define PETSC_INTERNAL_COMPL_0 1 821 #define PETSC_INTERNAL_COMPL_1 0 822 823 /*MC 824 PetscCompl - Expands to the integer complement of its argument 825 826 Synopsis: 827 #include <petscmacros.h> 828 int PetscCompl(b) 829 830 Input Parameter: 831 . b - Preprocessor variable, must expand to either integer literal 0 or 1 832 833 Output Parameter: 834 . <return-value> - Either integer literal 0 or 1 835 836 Notes: 837 Not available from Fortran. 838 839 Expands to integer literal 0 if b expands to 1, or integer literal 1 if b expands to 840 0. Behaviour is undefined if b expands to anything else. PetscCompl() will expand its 841 argument before returning the complement. 842 843 This macro can be useful for negating PetscDefined() inside macros e.g. 844 845 $ #define PETSC_DONT_HAVE_FOO PetscCompl(PetscDefined(HAVE_FOO)) 846 847 Example usage: 848 .vb 849 #define MY_VAR 1 850 PetscCompl(MY_VAR) -> 0 851 852 #undef MY_VAR 853 #define MY_VAR 0 854 PetscCompl(MY_VAR) -> 1 855 .ve 856 857 Level: beginner 858 859 .seealso: `PetscConcat()`, `PetscDefined()` 860 M*/ 861 #define PetscCompl(b) PetscConcat_(PETSC_INTERNAL_COMPL_, PetscExpand(b)) 862 863 /*MC 864 PetscDefined - Determine whether a boolean macro is defined 865 866 No Fortran Support 867 868 Synopsis: 869 #include <petscmacros.h> 870 int PetscDefined(def) 871 872 Input Parameter: 873 . def - PETSc-style preprocessor variable (without PETSC_ prepended!) 874 875 Output Parameter: 876 . <return-value> - Either integer literal 0 or 1 877 878 Notes: 879 `PetscDefined()` returns 1 if and only if "PETSC_ ## def" is defined (but empty) or defined to 880 integer literal 1. In all other cases, `PetscDefined()` returns integer literal 0. Therefore 881 this macro should not be used if its argument may be defined to a non-empty value other than 882 1. 883 884 The prefix "PETSC_" is automatically prepended to def. To avoid prepending "PETSC_", say to 885 add custom checks in user code, one should use `PetscDefined_()`. 886 887 $ #define FooDefined(d) PetscDefined_(PetscConcat(FOO_,d)) 888 889 Developer Notes: 890 Getting something that works in C and CPP for an arg that may or may not be defined is 891 tricky. Here, if we have "#define PETSC_HAVE_BOOGER 1" we match on the placeholder define, 892 insert the "0," for arg1 and generate the triplet (0, 1, 0). Then the last step cherry picks 893 the 2nd arg (a one). When PETSC_HAVE_BOOGER is not defined, we generate a (... 1, 0) pair, 894 and when the last step cherry picks the 2nd arg, we get a zero. 895 896 Our extra expansion via PetscDefined__take_second_expand() is needed with MSVC, which has a 897 nonconforming implementation of variadic macros. 898 899 Example Usage: 900 Suppose you would like to call either "foo()" or "bar()" depending on whether PETSC_USE_DEBUG 901 is defined then 902 903 .vb 904 #if PetscDefined(USE_DEBUG) 905 foo(); 906 #else 907 bar(); 908 #endif 909 910 // or alternatively within normal code 911 if (PetscDefined(USE_DEBUG)) { 912 foo(); 913 } else { 914 bar(); 915 } 916 .ve 917 918 is equivalent to 919 920 .vb 921 #if defined(PETSC_USE_DEBUG) 922 # if MY_DETECT_EMPTY_MACRO(PETSC_USE_DEBUG) // assuming you have such a macro 923 foo(); 924 # elif PETSC_USE_DEBUG == 1 925 foo(); 926 # else 927 bar(); 928 # endif 929 #else 930 bar(); 931 #endif 932 .ve 933 934 Level: intermediate 935 936 .seealso: `PetscHasAttribute()`, `PetscUnlikely()`, `PetscLikely()`, `PetscConcat()`, 937 `PetscExpandToNothing()`, `PetscCompl()` 938 M*/ 939 #define PetscDefined_arg_1 shift, 940 #define PetscDefined_arg_ shift, 941 #define PetscDefined__take_second_expanded(ignored, val, ...) val 942 #define PetscDefined__take_second_expand(args) PetscDefined__take_second_expanded args 943 #define PetscDefined__take_second(...) PetscDefined__take_second_expand((__VA_ARGS__)) 944 #define PetscDefined__(arg1_or_junk) PetscDefined__take_second(arg1_or_junk 1, 0, at_) 945 #define PetscDefined_(value) PetscDefined__(PetscConcat_(PetscDefined_arg_, value)) 946 #define PetscDefined(def) PetscDefined_(PetscConcat(PETSC_, def)) 947 948 /*MC 949 PetscUnlikelyDebug - Hints the compiler that the given condition is usually false, eliding 950 the check in optimized mode 951 952 No Fortran Support 953 954 Synopsis: 955 #include <petscmacros.h> 956 bool PetscUnlikelyDebug(bool cond) 957 958 Not Collective 959 960 Input Parameters: 961 . cond - Boolean expression 962 963 This returns the same truth value, it is only a hint to compilers that the result of cond is 964 likely to be false. When PETSc is compiled in optimized mode this will always return 965 false. Additionally, cond is guaranteed to not be evaluated when PETSc is compiled in 966 optimized mode. 967 968 Example usage: 969 This routine is shorthand for checking both the condition and whether PetscDefined(USE_DEBUG) 970 is true. So 971 972 .vb 973 if (PetscUnlikelyDebug(cond)) { 974 foo(); 975 } else { 976 bar(); 977 } 978 .ve 979 980 is equivalent to 981 982 .vb 983 if (PetscDefined(USE_DEBUG)) { 984 if (PetscUnlikely(cond)) { 985 foo(); 986 } else { 987 bar(); 988 } 989 } else { 990 bar(); 991 } 992 .ve 993 994 Level: advanced 995 996 .seealso: `PetscUnlikely()`, `PetscLikely()`, `PetscCall()`, `SETERRQ` 997 M*/ 998 #define PetscUnlikelyDebug(cond) (PetscDefined(USE_DEBUG) && PetscUnlikely(cond)) 999 1000 #if defined(PETSC_CLANG_STATIC_ANALYZER) 1001 // silence compiler warnings when using -pedantic, this is only used by the linter and it cares 1002 // not what ISO C allows 1003 #define PetscMacroReturns_(retexpr, ...) \ 1004 __extension__({ \ 1005 __VA_ARGS__; \ 1006 retexpr; \ 1007 }) 1008 #else 1009 #define PetscMacroReturns_(retexpr, ...) \ 1010 retexpr; \ 1011 do { \ 1012 __VA_ARGS__; \ 1013 } while (0) 1014 #endif 1015 1016 /*MC 1017 PetscExpandToNothing - Expands to absolutely nothing at all 1018 1019 No Fortran Support 1020 1021 Synopsis: 1022 #include <petscmacros.h> 1023 void PetscExpandToNothing(...) 1024 1025 Input Parameter: 1026 . __VA_ARGS__ - Anything at all 1027 1028 Notes: 1029 Must have at least 1 parameter. 1030 1031 Example usage: 1032 .vb 1033 PetscExpandToNothing(a,b,c) -> *nothing* 1034 .ve 1035 1036 Level: beginner 1037 1038 .seealso: `PetscConcat()`, `PetscDefined()`, `PetscStringize()`, `PetscExpand()` 1039 M*/ 1040 #define PetscExpandToNothing(...) 1041 1042 /*MC 1043 PetscMacroReturns - Define a macro body that returns a value 1044 1045 Synopsis: 1046 #include <petscmacros.h> 1047 return_type PetscMacroReturns(return_type retexpr, ...) 1048 1049 Input Parameters: 1050 + retexpr - The value or expression that the macro should return 1051 - __VA_ARGS__ - The body of the macro 1052 1053 Notes: 1054 Due to limitations of the C-preprocessor retexpr cannot depend on symbols declared in the 1055 body of the macro and should not depend on values produced as a result of the expression. The 1056 user should not assume that the result of this macro is equivalent to a single logical source 1057 line. It is not portable to use macros defined using this one in conditional or loop bodies 1058 without enclosing them in curly braces\: 1059 1060 .vb 1061 #define FOO(arg1) PetscMacroReturns(0,arg1+=10) // returns 0 1062 1063 int err,x = 10; 1064 1065 if (...) err = FOO(x); // ERROR, body of FOO() executed outside the if statement 1066 if (...) { err = FOO(x); } // OK 1067 1068 for (...) err = FOO(x); // ERROR, body of FOO() executed outside the loop 1069 for (...) { err = FOO(x); } // OK 1070 .ve 1071 1072 It is also not portable to use this macro directly inside function call, conditional, loop, 1073 or switch statements\: 1074 1075 .vb 1076 extern void bar(int); 1077 1078 int ret = FOO(x); 1079 1080 bar(FOO(x)); // ERROR, may not compile 1081 bar(ret); // OK 1082 1083 if (FOO(x)) // ERROR, may not compile 1084 if (ret) // OK 1085 .ve 1086 1087 Example usage: 1088 .vb 1089 #define MY_SIMPLE_RETURNING_MACRO(arg1) PetscMacroReturns(0,arg1+=10) 1090 1091 int x = 10; 1092 int err = MY_SIMPLE_RETURNING_MACRO(x); // err = 0, x = 20 1093 1094 // multiline macros allowed, but must declare with line continuation as usual 1095 #define MY_COMPLEX_RETURNING_MACRO(arg1) PetscMacroReturns(0, \ 1096 if (arg1 > 10) { \ 1097 puts("big int!"); \ 1098 } else { \ 1099 return 7355608; \ 1100 } \ 1101 ) 1102 1103 // if retexpr contains commas, must enclose it with braces 1104 #define MY_COMPLEX_RETEXPR_MACRO_1() PetscMacroReturns(x+=10,0,body...) 1105 #define MY_COMPLEX_RETEXPR_MACRO_2() PetscMacroReturns((x+=10,0),body...) 1106 1107 int x = 10; 1108 int y = MY_COMPLEX_RETEXPR_MACRO_1(); // ERROR, y = x = 20 not 0 1109 int z = MY_COMPLEX_RETEXPR_MACRO_2(); // OK, y = 0, x = 20 1110 .ve 1111 1112 Level: intermediate 1113 1114 .seealso: `PetscExpand()`, `PetscConcat()`, `PetscStringize()` 1115 M*/ 1116 #define PetscMacroReturns(retexpr, ...) PetscMacroReturns_(retexpr, __VA_ARGS__) 1117 1118 #define PetscMacroReturnStandard(...) PetscMacroReturns(PETSC_SUCCESS, __VA_ARGS__) 1119 1120 /*MC 1121 PETSC_STATIC_ARRAY_LENGTH - Return the length of a static array 1122 1123 Level: intermediate 1124 M*/ 1125 #define PETSC_STATIC_ARRAY_LENGTH(a) (sizeof(a) / sizeof((a)[0])) 1126 1127 /* 1128 These macros allow extracting out the first argument or all but the first argument from a macro __VAR_ARGS__ INSIDE another macro. 1129 1130 Example usage: 1131 1132 #define mymacro(obj,...) { 1133 PETSC_FIRST_ARG((__VA_ARGS__,unused)); 1134 f(22 PETSC_REST_ARG(__VA_ARGS__)); 1135 } 1136 1137 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 1138 1139 Reference: 1140 https://stackoverflow.com/questions/5588855/standard-alternative-to-gccs-va-args-trick 1141 */ 1142 #define PETSC_FIRST_ARG_(N, ...) N 1143 #define PETSC_FIRST_ARG(args) PETSC_FIRST_ARG_ args 1144 #define PETSC_SELECT_16TH(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, ...) a16 1145 #define PETSC_NUM(...) PETSC_SELECT_16TH(__VA_ARGS__, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, ONE, throwaway) 1146 #define PETSC_REST_HELPER_TWOORMORE(first, ...) , __VA_ARGS__ 1147 #define PETSC_REST_HELPER_ONE(first) 1148 #define PETSC_REST_HELPER2(qty, ...) PETSC_REST_HELPER_##qty(__VA_ARGS__) 1149 #define PETSC_REST_HELPER(qty, ...) PETSC_REST_HELPER2(qty, __VA_ARGS__) 1150 #define PETSC_REST_ARG(...) PETSC_REST_HELPER(PETSC_NUM(__VA_ARGS__), __VA_ARGS__) 1151 1152 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(name, ...) \ 1153 _Pragma(PetscStringize(name diagnostic push)) \ 1154 _Pragma(PetscStringize(name diagnostic ignored __VA_ARGS__)) 1155 1156 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(name) _Pragma(PetscStringize(name diagnostic pop)) 1157 1158 #if defined(__clang__) 1159 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(clang, __VA_ARGS__) 1160 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END() PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(clang) 1161 #elif defined(__GNUC__) || defined(__GNUG__) 1162 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_(GCC, __VA_ARGS__) 1163 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END() PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_(GCC) 1164 #endif 1165 1166 #ifndef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN 1167 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN(...) 1168 #define PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END(...) 1169 // only undefine these if they are not used 1170 #undef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_BEGIN_ 1171 #undef PETSC_PRAGMA_DIAGNOSTIC_IGNORED_END_ 1172 #endif 1173 1174 /* OpenMP support */ 1175 #if defined(_OPENMP) 1176 #if defined(_MSC_VER) 1177 #define PetscPragmaOMP(...) __pragma(__VA_ARGS__) 1178 #else 1179 #define PetscPragmaOMP(...) _Pragma(PetscStringize(omp __VA_ARGS__)) 1180 #endif 1181 #endif 1182 1183 #ifndef PetscPragmaOMP 1184 #define PetscPragmaOMP(...) 1185 #endif 1186 1187 /* PetscPragmaSIMD - from CeedPragmaSIMD */ 1188 #if defined(__NEC__) 1189 #define PetscPragmaSIMD _Pragma("_NEC ivdep") 1190 #elif defined(__INTEL_COMPILER) && !defined(_WIN32) 1191 #define PetscPragmaSIMD _Pragma("vector") 1192 #elif defined(__GNUC__) 1193 #if __GNUC__ >= 5 && !defined(__PGI) 1194 #define PetscPragmaSIMD _Pragma("GCC ivdep") 1195 #endif 1196 #elif defined(_OPENMP) && _OPENMP >= 201307 1197 #define PetscPragmaSIMD PetscPragmaOMP(simd) 1198 #elif defined(PETSC_HAVE_CRAY_VECTOR) 1199 #define PetscPragmaSIMD _Pragma("_CRI ivdep") 1200 #endif 1201 1202 #ifndef PetscPragmaSIMD 1203 #define PetscPragmaSIMD 1204 #endif 1205 1206 #endif /* PETSC_PREPROCESSOR_MACROS_H */ 1207