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