Actual source code: fp.c

  1: /*
  2:    IEEE error handler for all machines. Since each OS has
  3:    enough slight differences we have completely separate codes for each one.
  4: */

  6: /*
  7:   This feature test macro provides FE_NOMASK_ENV on GNU.  It must be defined
  8:   at the top of the file because other headers may pull in fenv.h even when
  9:   not strictly necessary.  Strictly speaking, we could include ONLY petscconf.h,
 10:   check PETSC_HAVE_FENV_H, and only define _GNU_SOURCE in that case, but such
 11:   shenanigans ought to be unnecessary.
 12: */
 13: #if !defined(_GNU_SOURCE)
 14:   #define _GNU_SOURCE
 15: #endif

 17: #include <petsc/private/petscimpl.h>
 18: #include <signal.h>
 19: #if defined(PETSC_HAVE_XMMINTRIN_H)
 20:   #include <xmmintrin.h>
 21: #endif

 23: struct PetscFPTrapLink {
 24:   PetscFPTrap             trapmode;
 25:   struct PetscFPTrapLink *next;
 26: };
 27: static PetscFPTrap             _trapmode = PETSC_FP_TRAP_OFF; /* Current trapping mode; see PetscDetermineInitialFPTrap() */
 28: static struct PetscFPTrapLink *_trapstack;                    /* Any pushed states of _trapmode */

 30: /*@
 31:   PetscFPTrapPush - push a floating point trapping mode, restored using `PetscFPTrapPop()`

 33:   Not Collective

 35:   Input Parameter:
 36: . trap - `PETSC_FP_TRAP_ON` or `PETSC_FP_TRAP_OFF` or any of the values passable to `PetscSetFPTrap()`

 38:   Level: advanced

 40:   Notes:
 41:   This only changes the trapping if the new mode is different than the current mode.

 43:   This routine is called to turn off trapping for certain LAPACK routines that assume that dividing
 44:   by zero is acceptable. In particular the routine ieeeck().

 46:   Most systems by default have all trapping turned off, but certain Fortran compilers have
 47:   link flags that turn on trapping before the program begins.
 48: .vb
 49:        gfortran -ffpe-trap=invalid,zero,overflow,underflow,denormal
 50:        ifort -fpe0
 51: .ve

 53: .seealso: `PetscFPTrapPop()`, `PetscSetFPTrap()`, `PetscDetermineInitialFPTrap()`
 54: @*/
 55: PetscErrorCode PetscFPTrapPush(PetscFPTrap trap)
 56: {
 57:   struct PetscFPTrapLink *link;

 59:   PetscFunctionBegin;
 60:   PetscCall(PetscNew(&link));
 61: #if defined(PETSC_HAVE_THREADSAFETY) && defined(PETSC_HAVE_OPENMP)
 62:   PetscPragmaOMP(critical)
 63: #endif
 64:   {
 65:     link->trapmode = _trapmode;
 66:     link->next     = _trapstack;
 67:     _trapstack     = link;
 68:   }
 69:   if (trap != _trapmode) PetscCall(PetscSetFPTrap(trap));
 70:   PetscFunctionReturn(PETSC_SUCCESS);
 71: }

 73: /*@
 74:   PetscFPTrapPop - push a floating point trapping mode, to be restored using `PetscFPTrapPop()`

 76:   Not Collective

 78:   Level: advanced

 80: .seealso: `PetscFPTrapPush()`, `PetscSetFPTrap()`, `PetscDetermineInitialFPTrap()`
 81: @*/
 82: PetscErrorCode PetscFPTrapPop(void)
 83: {
 84:   struct PetscFPTrapLink *link;

 86:   PetscFunctionBegin;
 87:   if (_trapstack->trapmode != _trapmode) PetscCall(PetscSetFPTrap(_trapstack->trapmode));
 88: #if defined(PETSC_HAVE_THREADSAFETY) && defined(PETSC_HAVE_OPENMP)
 89:   PetscPragmaOMP(critical)
 90: #endif
 91:   {
 92:     link       = _trapstack;
 93:     _trapstack = _trapstack->next;
 94:   }
 95:   PetscCall(PetscFree(link));
 96:   PetscFunctionReturn(PETSC_SUCCESS);
 97: }

 99: /*--------------------------------------- ---------------------------------------------------*/
100: #if defined(PETSC_HAVE_SUN4_STYLE_FPTRAP)
101:   #include <floatingpoint.h>

103: PETSC_EXTERN PetscErrorCode ieee_flags(char *, char *, char *, char **);
104: PETSC_EXTERN PetscErrorCode ieee_handler(char *, char *, sigfpe_handler_type(int, int, struct sigcontext *, char *));

106: static struct {
107:   int   code_no;
108:   char *name;
109: } error_codes[] = {
110:   {FPE_INTDIV_TRAP,   "integer divide"               },
111:   {FPE_FLTOPERR_TRAP, "IEEE operand error"           },
112:   {FPE_FLTOVF_TRAP,   "floating point overflow"      },
113:   {FPE_FLTUND_TRAP,   "floating point underflow"     },
114:   {FPE_FLTDIV_TRAP,   "floating pointing divide"     },
115:   {FPE_FLTINEX_TRAP,  "inexact floating point result"},
116:   {0,                 "unknown error"                }
117: };
118:   #define SIGPC(scp) (scp->sc_pc)

120: /* this function gets called if a trap has occurred and been caught */
121: sigfpe_handler_type PetscDefaultFPTrap(int sig, int code, struct sigcontext *scp, char *addr)
122: {
123:   int err_ind = -1;

125:   PetscFunctionBegin;
126:   for (int j = 0; error_codes[j].code_no; j++) {
127:     if (error_codes[j].code_no == code) err_ind = j;
128:   }

130:   if (err_ind >= 0) (void)(*PetscErrorPrintf)("*** %s occurred at pc=%X ***\n", error_codes[err_ind].name, SIGPC(scp));
131:   else (void)(*PetscErrorPrintf)("*** floating point error 0x%x occurred at pc=%X ***\n", code, SIGPC(scp));

133:   (void)PetscError(PETSC_COMM_SELF, PETSC_ERR_FP, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_REPEAT, "floating point error");
134:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
135:   PetscFunctionReturn(PETSC_SUCCESS);
136: }

138: /*@
139:    PetscSetFPTrap - Enables traps/exceptions on common floating point errors. This option may not work on certain systems or only a
140:    subset of exceptions may be trapable.

142:    Not Collective

144:    Input Parameter:
145: .  flag - values are
146: .vb
147:     PETSC_FP_TRAP_OFF   - do not trap any exceptions
148:     PETSC_FP_TRAP_ON - all exceptions that are possible on the system except underflow
149:     PETSC_FP_TRAP_INDIV - integer divide by zero
150:     PETSC_FP_TRAP_FLTOPERR - improper argument to function, for example with real numbers, the square root of a negative number
151:     PETSC_FP_TRAP_FLTOVF - overflow
152:     PETSC_FP_TRAP_FLTUND - underflow - not trapped by default on most systems
153:     PETSC_FP_TRAP_FLTDIV - floating point divide by zero
154:     PETSC_FP_TRAP_FLTINEX - inexact floating point result
155: .ve

157:    Options Database Key:
158: .  -fp_trap <off,on> - turn on or off trapping of floating point exceptions

160:    Level: advanced

162:    Notes:
163:    Preferred usage is `PetscFPTrapPush()` and `PetscFPTrapPop()` instead of this routine

165:    Currently only `PETSC_FP_TRAP_OFF` and `PETSC_FP_TRAP_ON` are handled. All others are treated as `PETSC_FP_TRAP_ON`.

167:    The values are bit values and may be |ed together in the function call

169:    On systems that support it this routine causes floating point
170:    overflow, divide-by-zero, and invalid-operand (e.g., a NaN), but not underflow, to
171:    cause a message to be printed and the program to exit.

173:    On many common systems, the floating
174:    point exception state is not preserved from the location where the trap
175:    occurred through to the signal handler.  In this case, the signal handler
176:    will just say that an unknown floating point exception occurred and which
177:    function it occurred in.  If you run with -fp_trap in a debugger, it will
178:    break on the line where the error occurred.  On systems that support C99
179:    floating point exception handling You can check which
180:    exception occurred using fetestexcept(FE_ALL_EXCEPT).  See fenv.h
181:    (usually at /usr/include/bits/fenv.h) for the enum values on your system.

183: .seealso: `PetscFPTrapPush()`, `PetscFPTrapPop()`, `PetscDetermineInitialFPTrap()`
184: @*/
185: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
186: {
187:   char *out;

189:   PetscFunctionBegin;
190:   /* Clear accumulated exceptions.  Used to suppress meaningless messages from f77 programs */
191:   (void)ieee_flags("clear", "exception", "all", &out);
192:   if (flag == PETSC_FP_TRAP_ON) {
193:     /*
194:       To trap more fp exceptions, including underflow, change the line below to
195:       if (ieee_handler("set","all",PetscDefaultFPTrap)) {
196:     */
197:     if (ieee_handler("set", "common", PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't set floatingpoint handler\n");
198:   } else if (ieee_handler("clear", "common", PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");

200:   _trapmode = flag;
201:   PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_SUN4_STYLE_FPTRAP\n"));
202:   PetscFunctionReturn(PETSC_SUCCESS);
203: }

205: /*@
206:    PetscDetermineInitialFPTrap - Attempts to determine the floating point trapping that exists when `PetscInitialize()` is called

208:    Not Collective

210:    Note:
211:    Currently only supported on Linux and macOS. Checks if divide by zero is enable and if so declares that trapping is on.

213:    Level: advanced

215: .seealso: `PetscFPTrapPush()`, `PetscFPTrapPop()`, `PetscDetermineInitialFPTrap()`
216: @*/
217: PetscErrorCode PetscDetermineInitialFPTrap(void)
218: {
219:   PetscFunctionBegin;
220:   PetscCall(PetscInfo(NULL, "Unable to determine initial floating point trapping. Assuming it is off\n"));
221:   PetscFunctionReturn(PETSC_SUCCESS);
222: }

224: /* -------------------------------------------------------------------------------------------*/
225: #elif defined(PETSC_HAVE_SOLARIS_STYLE_FPTRAP)
226:   #include <sunmath.h>
227:   #include <floatingpoint.h>
228:   #include <siginfo.h>
229:   #include <ucontext.h>

231: static struct {
232:   int   code_no;
233:   char *name;
234: } error_codes[] = {
235:   {FPE_FLTINV, "invalid floating point operand"},
236:   {FPE_FLTRES, "inexact floating point result" },
237:   {FPE_FLTDIV, "division-by-zero"              },
238:   {FPE_FLTUND, "floating point underflow"      },
239:   {FPE_FLTOVF, "floating point overflow"       },
240:   {0,          "unknown error"                 }
241: };
242:   #define SIGPC(scp) (scp->si_addr)

244: void PetscDefaultFPTrap(int sig, siginfo_t *scp, ucontext_t *uap)
245: {
246:   int err_ind = -1, code = scp->si_code;

248:   PetscFunctionBegin;
249:   for (int j = 0; error_codes[j].code_no; j++) {
250:     if (error_codes[j].code_no == code) err_ind = j;
251:   }

253:   if (err_ind >= 0) (void)(*PetscErrorPrintf)("*** %s occurred at pc=%X ***\n", error_codes[err_ind].name, SIGPC(scp));
254:   else (*PetscErrorPrintf)("*** floating point error 0x%x occurred at pc=%X ***\n", code, SIGPC(scp));

256:   PetscError(PETSC_COMM_SELF, 0, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_REPEAT, "floating point error");
257:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
258: }

260: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
261: {
262:   char *out;

264:   PetscFunctionBegin;
265:   /* Clear accumulated exceptions.  Used to suppress meaningless messages from f77 programs */
266:   (void)ieee_flags("clear", "exception", "all", &out);
267:   if (flag == PETSC_FP_TRAP_ON) {
268:     if (ieee_handler("set", "common", (sigfpe_handler_type)PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't set floating point handler\n");
269:   } else {
270:     if (ieee_handler("clear", "common", (sigfpe_handler_type)PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");
271:   }
272:   _trapmode = flag;
273:   PetscCall(PetscInfo(NULL,"Using PETSC_HAVE_SOLARIS_STYLE_FPTRAP\n");
274:   PetscFunctionReturn(PETSC_SUCCESS);
275: }

277: PetscErrorCode PetscDetermineInitialFPTrap(void)
278: {
279:   PetscFunctionBegin;
280:   PetscCall(PetscInfo(NULL, "Unable to determine initial floating point trapping. Assuming it is off\n"));
281:   PetscFunctionReturn(PETSC_SUCCESS);
282: }

284: /* ------------------------------------------------------------------------------------------*/
285: #elif defined(PETSC_HAVE_IRIX_STYLE_FPTRAP)
286:   #include <sigfpe.h>
287: static struct {
288:   int   code_no;
289:   char *name;
290: } error_codes[] = {
291:   {_INVALID, "IEEE operand error"      },
292:   {_OVERFL,  "floating point overflow" },
293:   {_UNDERFL, "floating point underflow"},
294:   {_DIVZERO, "floating point divide"   },
295:   {0,        "unknown error"           }
296: };
297: void PetscDefaultFPTrap(unsigned exception[], int val[])
298: {
299:   int err_ind = -1, code = exception[0];

301:   PetscFunctionBegin;
302:   for (int j = 0; error_codes[j].code_no; j++) {
303:     if (error_codes[j].code_no == code) err_ind = j;
304:   }
305:   if (err_ind >= 0) (void)(*PetscErrorPrintf)("*** %s occurred ***\n", error_codes[err_ind].name);
306:   else (void)(*PetscErrorPrintf)("*** floating point error 0x%x occurred ***\n", code);

308:   (void)PetscError(PETSC_COMM_SELF, 0, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_REPEAT, "floating point error");
309:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
310: }

312: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
313: {
314:   PetscFunctionBegin;
315:   if (flag == PETSC_FP_TRAP_ON) handle_sigfpes(_ON, , _EN_UNDERFL | _EN_OVERFL | _EN_DIVZERO | _EN_INVALID, PetscDefaultFPTrap, _ABORT_ON_ERROR, 0);
316:   else handle_sigfpes(_OFF, _EN_UNDERFL | _EN_OVERFL | _EN_DIVZERO | _EN_INVALID, 0, _ABORT_ON_ERROR, 0);
317:   _trapmode = flag;
318:   PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_IRIX_STYLE_FPTRAP\n"));
319:   PetscFunctionReturn(PETSC_SUCCESS);
320: }

322: PetscErrorCode PetscDetermineInitialFPTrap(void)
323: {
324:   PetscFunctionBegin;
325:   PetscCall(PetscInfo(NULL, "Unable to determine initial floating point trapping. Assuming it is off\n"));
326:   PetscFunctionReturn(PETSC_SUCCESS);
327: }

329: /*----------------------------------------------- --------------------------------------------*/
330: #elif defined(PETSC_HAVE_RS6000_STYLE_FPTRAP)
331: /* In "fast" mode, floating point traps are imprecise and ignored.
332:    This is the reason for the fptrap(FP_TRAP_SYNC) call */
333: struct sigcontext;
334:   #include <fpxcp.h>
335:   #include <fptrap.h>
336:   #define FPE_FLTOPERR_TRAP (fptrap_t)(0x20000000)
337:   #define FPE_FLTOVF_TRAP   (fptrap_t)(0x10000000)
338:   #define FPE_FLTUND_TRAP   (fptrap_t)(0x08000000)
339:   #define FPE_FLTDIV_TRAP   (fptrap_t)(0x04000000)
340:   #define FPE_FLTINEX_TRAP  (fptrap_t)(0x02000000)

342: static struct {
343:   int   code_no;
344:   char *name;
345: } error_codes[] = {
346:   {FPE_FLTOPERR_TRAP, "IEEE operand error"           },
347:   {FPE_FLTOVF_TRAP,   "floating point overflow"      },
348:   {FPE_FLTUND_TRAP,   "floating point underflow"     },
349:   {FPE_FLTDIV_TRAP,   "floating point divide"        },
350:   {FPE_FLTINEX_TRAP,  "inexact floating point result"},
351:   < {0,                 "unknown error"                }
352: };
353:   #define SIGPC(scp)        (0) /* Info MIGHT be in scp->sc_jmpbuf.jmp_context.iar */
354: /*
355:    For some reason, scp->sc_jmpbuf does not work on the RS6000, even though
356:    it looks like it should from the include definitions.  It is probably
357:    some strange interaction with the "POSIX_SOURCE" that we require.
358: */

360: void PetscDefaultFPTrap(int sig, int code, struct sigcontext *scp)
361: {
362:   int      err_ind, j;
363:   fp_ctx_t flt_context;

365:   PetscFunctionBegin;
366:   fp_sh_trap_info(scp, &flt_context);

368:   err_ind = -1;
369:   for (j = 0; error_codes[j].code_no; j++) {
370:     if (error_codes[j].code_no == flt_context.trap) err_ind = j;
371:   }

373:   if (err_ind >= 0) (void)(*PetscErrorPrintf)("*** %s occurred ***\n", error_codes[err_ind].name);
374:   else (void)(*PetscErrorPrintf)("*** floating point error 0x%x occurred ***\n", flt_context.trap);

376:   (void)PetscError(PETSC_COMM_SELF, 0, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_REPEAT, "floating point error");
377:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
378: }

380: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
381: {
382:   PetscFunctionBegin;
383:   if (flag == PETSC_FP_TRAP_ON) {
384:     signal(SIGFPE, (void (*)(int))PetscDefaultFPTrap);
385:     fp_trap(FP_TRAP_SYNC);
386:     /* fp_enable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW | TRP_UNDERFLOW); */
387:     fp_enable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW);
388:   } else {
389:     signal(SIGFPE, SIG_DFL);
390:     fp_disable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW | TRP_UNDERFLOW);
391:     fp_trap(FP_TRAP_OFF);
392:   }
393:   _trapmode = flag;
394:   PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_RS6000_STYLE_FPTRAP\n"));
395:   PetscFunctionReturn(PETSC_SUCCESS);
396: }

398: PetscErrorCode PetscDetermineInitialFPTrap(void)
399: {
400:   PetscFunctionBegin;
401:   PetscCall(PetscInfo(NULL, "Unable to determine initial floating point trapping. Assuming it is off\n"));
402:   PetscFunctionReturn(PETSC_SUCCESS);
403: }

405: /* ------------------------------------------------------------*/
406: #elif defined(PETSC_HAVE_WINDOWS_COMPILERS)
407:   #include <float.h>
408: void PetscDefaultFPTrap(int sig)
409: {
410:   PetscFunctionBegin;
411:   (void)(*PetscErrorPrintf)("*** floating point error occurred ***\n");
412:   (void)PetscError(PETSC_COMM_SELF, 0, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_REPEAT, "floating point error");
413:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
414: }

416: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
417: {
418:   unsigned int cw;

420:   PetscFunctionBegin;
421:   if (flag == PETSC_FP_TRAP_ON) {
422:     /* cw = _EM_INVALID | _EM_ZERODIVIDE | _EM_OVERFLOW | _EM_UNDERFLOW; */
423:     cw = _EM_INVALID | _EM_ZERODIVIDE | _EM_OVERFLOW;
424:     PetscCheck(SIG_ERR != signal(SIGFPE, PetscDefaultFPTrap), PETSC_COMM_SELF, PETSC_ERR_LIB, "Can't set floating point handler");
425:   } else {
426:     cw = 0;
427:     PetscCheck(SIG_ERR != signal(SIGFPE, SIG_DFL), PETSC_COMM_SELF, PETSC_ERR_LIB, "Can't clear floating point handler");
428:   }
429:   (void)_controlfp(0, cw);
430:   _trapmode = flag;
431:   PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_WINDOWS_COMPILERS FPTRAP\n"));
432:   PetscFunctionReturn(PETSC_SUCCESS);
433: }

435: PetscErrorCode PetscDetermineInitialFPTrap(void)
436: {
437:   PetscFunctionBegin;
438:   PetscCall(PetscInfo(NULL, "Unable to determine initial floating point trapping. Assuming it is off\n"));
439:   PetscFunctionReturn(PETSC_SUCCESS);
440: }

442: /* ------------------------------------------------------------*/
443: #elif defined(PETSC_HAVE_FENV_H) && !defined(__cplusplus)
444:   /*
445:    C99 style floating point environment.

447:    Note that C99 merely specifies how to save, restore, and clear the floating
448:    point environment as well as defining an enumeration of exception codes.  In
449:    particular, C99 does not specify how to make floating point exceptions raise
450:    a signal.  Glibc offers this capability through FE_NOMASK_ENV (or with finer
451:    granularity, feenableexcept()), xmmintrin.h offers _MM_SET_EXCEPTION_MASK().
452: */
453:   #include <fenv.h>
454:   #if defined(PETSC_HAVE_FE_VALUES)
455: typedef struct {
456:   int         code;
457:   const char *name;
458: } FPNode;
459: static const FPNode error_codes[] = {
460:   {FE_DIVBYZERO, "divide by zero"                                 },
461:   {FE_INEXACT,   "inexact floating point result"                  },
462:   {FE_INVALID,   "invalid floating point arguments (domain error)"},
463:   {FE_OVERFLOW,  "floating point overflow"                        },
464:   {FE_UNDERFLOW, "floating point underflow"                       },
465:   {0,            "unknown error"                                  }
466: };
467:   #endif

469: void PetscDefaultFPTrap(int sig)
470: {
471:   #if defined(PETSC_HAVE_FE_VALUES)
472:   const FPNode *node;
473:   int           code;
474:   PetscBool     matched = PETSC_FALSE;
475:   #endif

477:   PetscFunctionBegin;
478:   /* Note: While it is possible for the exception state to be preserved by the
479:    * kernel, this seems to be rare which makes the following flag testing almost
480:    * useless.  But on a system where the flags can be preserved, it would provide
481:    * more detail.
482:    */
483:   #if defined(PETSC_HAVE_FE_VALUES)
484:   code = fetestexcept(FE_ALL_EXCEPT);
485:   for (node = &error_codes[0]; node->code; node++) {
486:     if (code & node->code) {
487:       matched = PETSC_TRUE;
488:       (void)(*PetscErrorPrintf)("*** floating point error \"%s\" occurred ***\n", node->name);
489:       code &= ~node->code; /* Unset this flag since it has been processed */
490:     }
491:   }
492:   if (!matched || code) { /* If any remaining flags are set, or we didn't process any flags */
493:     (void)(*PetscErrorPrintf)("*** unknown floating point error occurred ***\n");
494:     (void)(*PetscErrorPrintf)("The specific exception can be determined by running in a debugger.  When the\n");
495:     (void)(*PetscErrorPrintf)("debugger traps the signal, the exception can be found with fetestexcept(0x%x)\n", FE_ALL_EXCEPT);
496:     (void)(*PetscErrorPrintf)("where the result is a bitwise OR of the following flags:\n");
497:     (void)(*PetscErrorPrintf)("FE_INVALID=0x%x FE_DIVBYZERO=0x%x FE_OVERFLOW=0x%x FE_UNDERFLOW=0x%x FE_INEXACT=0x%x\n", FE_INVALID, FE_DIVBYZERO, FE_OVERFLOW, FE_UNDERFLOW, FE_INEXACT);
498:   }
499:   #else
500:   (void)(*PetscErrorPrintf)("*** unknown floating point error occurred ***\n");
501:   #endif

503:   (void)(*PetscErrorPrintf)("Try option -start_in_debugger\n");
504:   #if PetscDefined(USE_DEBUG)
505:     #if !PetscDefined(HAVE_THREADSAFETY)
506:   (void)(*PetscErrorPrintf)("likely location of problem given in stack below\n");
507:   (void)(*PetscErrorPrintf)("---------------------  Stack Frames ------------------------------------\n");
508:   (void)PetscStackView(PETSC_STDOUT);
509:     #endif
510:   #else
511:   (void)(*PetscErrorPrintf)("configure using --with-debugging=yes, recompile, link, and run \n");
512:   (void)(*PetscErrorPrintf)("with -start_in_debugger to get more information on the crash.\n");
513:   #endif
514:   (void)PetscError(PETSC_COMM_SELF, 0, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_INITIAL, "trapped floating point error");
515:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
516: }

518: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
519: {
520:   PetscFunctionBegin;
521:   if (flag == PETSC_FP_TRAP_ON) {
522:     /* Clear any flags that are currently set so that activating trapping will not immediately call the signal handler. */
523:     PetscCheck(!feclearexcept(FE_ALL_EXCEPT), PETSC_COMM_SELF, PETSC_ERR_LIB, "Cannot clear floating point exception flags");
524:   #if defined(FE_NOMASK_ENV) && defined(PETSC_HAVE_FE_VALUES)
525:     /* Could use fesetenv(FE_NOMASK_ENV), but that causes spurious exceptions (like gettimeofday() -> PetscLogDouble). */
526:     /* PetscCheck(feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) != -1,PETSC_COMM_SELF,PETSC_ERR_LIB,"Cannot activate floating point exceptions"); */
527:     /* Doesn't work on AArch64 targets. There's a known hardware limitation. Need to detect hardware at configure time? */
528:     PetscCheck(feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW) != -1, PETSC_COMM_SELF, PETSC_ERR_LIB, "Cannot activate floating point exceptions");
529:     PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_FENV_H FPTRAP with FE_NOMASK_ENV\n"));
530:   #elif defined PETSC_HAVE_XMMINTRIN_H
531:     _MM_SET_EXCEPTION_MASK(_MM_GET_EXCEPTION_MASK() & ~_MM_MASK_DIV_ZERO);
532:     /* _MM_SET_EXCEPTION_MASK(_MM_GET_EXCEPTION_MASK() & ~_MM_MASK_UNDERFLOW); */
533:     _MM_SET_EXCEPTION_MASK(_MM_GET_EXCEPTION_MASK() & ~_MM_MASK_OVERFLOW);
534:     _MM_SET_EXCEPTION_MASK(_MM_GET_EXCEPTION_MASK() & ~_MM_MASK_INVALID);
535:     PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_FENV_H FPTRAP with PETSC_HAVE_XMMINTRIN_H\n"));
536:   #else
537:     /* C99 does not provide a way to modify the environment so there is no portable way to activate trapping. */
538:     PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_FENV_H FPTRAP\n"));
539:   #endif
540:     PetscCheck(SIG_ERR != signal(SIGFPE, PetscDefaultFPTrap), PETSC_COMM_SELF, PETSC_ERR_LIB, "Can't set floating point handler");
541:   } else {
542:     PetscCheck(!fesetenv(FE_DFL_ENV), PETSC_COMM_SELF, PETSC_ERR_LIB, "Cannot disable floating point exceptions");
543:     /* can use _MM_SET_EXCEPTION_MASK(_MM_GET_EXCEPTION_MASK() | _MM_MASK_UNDERFLOW); if PETSC_HAVE_XMMINTRIN_H exists */
544:     PetscCheck(SIG_ERR != signal(SIGFPE, SIG_DFL), PETSC_COMM_SELF, PETSC_ERR_LIB, "Can't clear floating point handler");
545:   }
546:   _trapmode = flag;
547:   PetscFunctionReturn(PETSC_SUCCESS);
548: }

550: PetscErrorCode PetscDetermineInitialFPTrap(void)
551: {
552:   #if defined(FE_NOMASK_ENV) || defined PETSC_HAVE_XMMINTRIN_H
553:   unsigned int flags;
554:   #endif

556:   PetscFunctionBegin;
557:   #if defined(FE_NOMASK_ENV)
558:   flags = fegetexcept();
559:   if (flags & FE_DIVBYZERO) {
560:   #elif defined PETSC_HAVE_XMMINTRIN_H
561:   flags = _MM_GET_EXCEPTION_MASK();
562:   if (!(flags & _MM_MASK_DIV_ZERO)) {
563:   #else
564:   PetscCall(PetscInfo(NULL, "Floating point trapping unknown, assuming off\n"));
565:   PetscFunctionReturn(PETSC_SUCCESS);
566:   #endif
567:   #if defined(FE_NOMASK_ENV) || defined PETSC_HAVE_XMMINTRIN_H
568:     _trapmode = PETSC_FP_TRAP_ON;
569:     PetscCall(PetscInfo(NULL, "Floating point trapping is on by default %d\n", flags));
570:   } else {
571:     _trapmode = PETSC_FP_TRAP_OFF;
572:     PetscCall(PetscInfo(NULL, "Floating point trapping is off by default %d\n", flags));
573:   }
574:   PetscFunctionReturn(PETSC_SUCCESS);
575:   #endif
576: }

578: /* ------------------------------------------------------------*/
579: #elif defined(PETSC_HAVE_IEEEFP_H)
580:   #include <ieeefp.h>
581: void PetscDefaultFPTrap(int sig)
582: {
583:   PetscFunctionBegin;
584:   (void)(*PetscErrorPrintf)("*** floating point error occurred ***\n");
585:   (void)PetscError(PETSC_COMM_SELF, 0, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_REPEAT, "floating point error");
586:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
587: }

589: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
590: {
591:   PetscFunctionBegin;
592:   if (flag == PETSC_FP_TRAP_ON) {
593:   #if defined(PETSC_HAVE_FPRESETSTICKY)
594:     fpresetsticky(fpgetsticky());
595:   #elif defined(PETSC_HAVE_FPSETSTICKY)
596:     fpsetsticky(fpgetsticky());
597:   #endif
598:     fpsetmask(FP_X_INV | FP_X_DZ | FP_X_OFL | FP_X_OFL);
599:     PetscCheck(SIG_ERR != signal(SIGFPE, PetscDefaultFPTrap), PETSC_COMM_SELF, PETSC_ERR_LIB, "Can't set floating point handler");
600:   } else {
601:   #if defined(PETSC_HAVE_FPRESETSTICKY)
602:     fpresetsticky(fpgetsticky());
603:   #elif defined(PETSC_HAVE_FPSETSTICKY)
604:     fpsetsticky(fpgetsticky());
605:   #endif
606:     fpsetmask(0);
607:     PetscCheck(SIG_ERR != signal(SIGFPE, SIG_DFL), PETSC_COMM_SELF, PETSC_ERR_LIB, "Can't clear floating point handler");
608:   }
609:   _trapmode = flag;
610:   PetscCall(PetscInfo(NULL, "Using PETSC_HAVE_IEEEFP_H FPTRAP\n"));
611:   PetscFunctionReturn(PETSC_SUCCESS);
612: }

614: PetscErrorCode PetscDetermineInitialFPTrap(void)
615: {
616:   PetscFunctionBegin;
617:   PetscCall(PetscInfo(NULL, "Unable to determine initial floating point trapping. Assuming it is off\n"));
618:   PetscFunctionReturn(PETSC_SUCCESS);
619: }

621: /* -------------------------Default -----------------------------------*/
622: #else

624: static void PetscDefaultFPTrap(int sig)
625: {
626:   PetscFunctionBegin;
627:   (void)(*PetscErrorPrintf)("*** floating point error occurred ***\n");
628:   (void)PetscError(PETSC_COMM_SELF, 0, NULL, NULL, PETSC_ERR_FP, PETSC_ERROR_REPEAT, "floating point error");
629:   PETSCABORT(MPI_COMM_WORLD, PETSC_ERR_FP);
630: }

632: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
633: {
634:   PetscFunctionBegin;
635:   if (flag == PETSC_FP_TRAP_ON) {
636:     if (SIG_ERR == signal(SIGFPE, PetscDefaultFPTrap)) PetscCall((*PetscErrorPrintf)("Can't set floatingpoint handler\n"));
637:   } else if (SIG_ERR == signal(SIGFPE, SIG_DFL)) PetscCall((*PetscErrorPrintf)("Can't clear floatingpoint handler\n"));

639:   _trapmode = flag;
640:   PetscCall(PetscInfo(NULL, "Using default FPTRAP\n"));
641:   PetscFunctionReturn(PETSC_SUCCESS);
642: }

644: PetscErrorCode PetscDetermineInitialFPTrap(void)
645: {
646:   PetscFunctionBegin;
647:   PetscCall(PetscInfo(NULL, "Unable to determine initial floating point trapping. Assuming it is off\n"));
648:   PetscFunctionReturn(PETSC_SUCCESS);
649: }
650: #endif