Actual source code: fp.c

petsc-dev 2014-07-24
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  2: /*
  3: *   IEEE error handler for all machines. Since each machine has
  4: *   enough slight differences we have completely separate codes for each one.
  5: *
  6: */

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

 19: #include <petscsys.h>           /*I  "petscsys.h"  I*/
 20: #include <signal.h>

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

 31: /*@
 32:    PetscFPTrapPush - push a floating point trapping mode, to be restored using PetscFPTrapPop()

 34:    Not Collective

 36:    Input Arguments:
 37: . trap - PETSC_FP_TRAP_ON or PETSC_FP_TRAP_OFF

 39:    Level: advanced

 41: .seealso: PetscFPTrapPop(), PetscSetFPTrap()
 42: @*/
 43: PetscErrorCode PetscFPTrapPush(PetscFPTrap trap)
 44: {
 45:   PetscErrorCode         ierr;
 46:   struct PetscFPTrapLink *link;

 49:   PetscMalloc(sizeof(*link),&link);
 50:   link->trapmode = _trapmode;
 51:   link->next     = _trapstack;
 52:   _trapstack     = link;
 53:   if (trap != _trapmode) {PetscSetFPTrap(trap);}
 54:   return(0);
 55: }

 59: /*@
 60:    PetscFPTrapPop - push a floating point trapping mode, to be restored using PetscFPTrapPop()

 62:    Not Collective

 64:    Level: advanced

 66: .seealso: PetscFPTrapPush(), PetscSetFPTrap()
 67: @*/
 68: PetscErrorCode PetscFPTrapPop(void)
 69: {
 70:   PetscErrorCode         ierr;
 71:   struct PetscFPTrapLink *link;

 74:   if (_trapstack->trapmode != _trapmode) {PetscSetFPTrap(_trapstack->trapmode);}
 75:   link       = _trapstack;
 76:   _trapstack = _trapstack->next;
 77:   PetscFree(link);
 78:   return(0);
 79: }

 81: /*--------------------------------------- ---------------------------------------------------*/
 82: #if defined(PETSC_HAVE_SUN4_STYLE_FPTRAP)
 83: #include <floatingpoint.h>

 85: PETSC_EXTERN PetscErrorCode ieee_flags(char*,char*,char*,char**);
 86: PETSC_EXTERN PetscErrorCode ieee_handler(char*,char*,sigfpe_handler_type(int,int,struct sigcontext*,char*));

 88: static struct { int code_no; char *name; } error_codes[] = {
 89:   { FPE_INTDIV_TRAP    ,"integer divide" },
 90:   { FPE_FLTOPERR_TRAP  ,"IEEE operand error" },
 91:   { FPE_FLTOVF_TRAP    ,"floating point overflow" },
 92:   { FPE_FLTUND_TRAP    ,"floating point underflow" },
 93:   { FPE_FLTDIV_TRAP    ,"floating pointing divide" },
 94:   { FPE_FLTINEX_TRAP   ,"inexact floating point result" },
 95:   { 0                  ,"unknown error" }
 96: };
 97: #define SIGPC(scp) (scp->sc_pc)

101: sigfpe_handler_type PetscDefaultFPTrap(int sig,int code,struct sigcontext *scp,char *addr)
102: {
104:   int            err_ind = -1,j;

107:   for (j = 0; error_codes[j].code_no; j++) {
108:     if (error_codes[j].code_no == code) err_ind = j;
109:   }

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

114:   PetscError(PETSC_COMM_SELF,PETSC_ERR_FP,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
115:   MPI_Abort(PETSC_COMM_WORLD,0);
116:   return(0);
117: }

121: /*@
122:    PetscSetFPTrap - Enables traps/exceptions on common floating point errors.
123:                     This option may not work on certain machines.

125:    Not Collective

127:    Input Parameters:
128: .  flag - PETSC_FP_TRAP_ON, PETSC_FP_TRAP_OFF.

130:    Options Database Keys:
131: .  -fp_trap - Activates floating point trapping

133:    Level: advanced

135:    Description:
136:    On systems that support it, this routine causes floating point
137:    overflow, divide-by-zero, and invalid-operand (e.g., a NaN) to
138:    cause a message to be printed and the program to exit.

140:    Note:
141:    On many common systems including x86 and x86-64 Linux, the floating
142:    point exception state is not preserved from the location where the trap
143:    occurred through to the signal handler.  In this case, the signal handler
144:    will just say that an unknown floating point exception occurred and which
145:    function it occurred in.  If you run with -fp_trap in a debugger, it will
146:    break on the line where the error occurred.  You can check which
147:    exception occurred using fetestexcept(FE_ALL_EXCEPT).  See fenv.h
148:    (usually at /usr/include/bits/fenv.h) for the enum values on your system.

150:    Caution:
151:    On certain machines, in particular the IBM rs6000, floating point
152:    trapping is VERY slow!

154:    Concepts: floating point exceptions^trapping
155:    Concepts: divide by zero

157: .seealso: PetscFPTrapPush(), PetscFPTrapPop()
158: @*/
159: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
160: {
161:   char *out;

164:   /* Clear accumulated exceptions.  Used to suppress meaningless messages from f77 programs */
165:   (void) ieee_flags("clear","exception","all",&out);
166:   if (flag == PETSC_FP_TRAP_ON) {
167:     /*
168:       To trap more fp exceptions, including underflow, change the line below to
169:       if (ieee_handler("set","all",PetscDefaultFPTrap)) {
170:     */
171:     if (ieee_handler("set","common",PetscDefaultFPTrap))        (*PetscErrorPrintf)("Can't set floatingpoint handler\n");
172:   } else if (ieee_handler("clear","common",PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");

174:   _trapmode = flag;
175:   return(0);
176: }

178: /* -------------------------------------------------------------------------------------------*/
179: #elif defined(PETSC_HAVE_SOLARIS_STYLE_FPTRAP)
180: #include <sunmath.h>
181: #include <floatingpoint.h>
182: #include <siginfo.h>
183: #include <ucontext.h>

185: static struct { int code_no; char *name; } error_codes[] = {
186:   { FPE_FLTINV,"invalid floating point operand"},
187:   { FPE_FLTRES,"inexact floating point result"},
188:   { FPE_FLTDIV,"division-by-zero"},
189:   { FPE_FLTUND,"floating point underflow"},
190:   { FPE_FLTOVF,"floating point overflow"},
191:   { 0,         "unknown error"}
192: };
193: #define SIGPC(scp) (scp->si_addr)

197: void PetscDefaultFPTrap(int sig,siginfo_t *scp,ucontext_t *uap)
198: {
199:   int            err_ind,j,code = scp->si_code;

203:   err_ind = -1;
204:   for (j = 0; error_codes[j].code_no; j++) {
205:     if (error_codes[j].code_no == code) err_ind = j;
206:   }

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

211:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
212:   MPI_Abort(PETSC_COMM_WORLD,0);
213: }

217: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
218: {
219:   char *out;

222:   /* Clear accumulated exceptions.  Used to suppress meaningless messages from f77 programs */
223:   (void) ieee_flags("clear","exception","all",&out);
224:   if (flag == PETSC_FP_TRAP_ON) {
225:     if (ieee_handler("set","common",(sigfpe_handler_type)PetscDefaultFPTrap))        (*PetscErrorPrintf)("Can't set floating point handler\n");
226:   } else if (ieee_handler("clear","common",(sigfpe_handler_type)PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");
227:   _trapmode = flag;
228:   return(0);
229: }

231: /* ------------------------------------------------------------------------------------------*/

233: #elif defined(PETSC_HAVE_IRIX_STYLE_FPTRAP)
234: #include <sigfpe.h>
235: static struct { int code_no; char *name; } error_codes[] = {
236:   { _INVALID   ,"IEEE operand error" },
237:   { _OVERFL    ,"floating point overflow" },
238:   { _UNDERFL   ,"floating point underflow" },
239:   { _DIVZERO   ,"floating point divide" },
240:   { 0          ,"unknown error" }
241: } ;
244: void PetscDefaultFPTrap(unsigned exception[],int val[])
245: {
246:   int err_ind,j,code;

249:   code    = exception[0];
250:   err_ind = -1;
251:   for (j = 0; error_codes[j].code_no; j++) {
252:     if (error_codes[j].code_no == code) err_ind = j;
253:   }
254:   if (err_ind >= 0) (*PetscErrorPrintf)("*** %s occurred ***\n",error_codes[err_ind].name);
255:   else              (*PetscErrorPrintf)("*** floating point error 0x%x occurred ***\n",code);

257:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
258:   MPI_Abort(PETSC_COMM_WORLD,0);
259: }

263: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
264: {
266:   if (flag == PETSC_FP_TRAP_ON) handle_sigfpes(_ON,_EN_OVERFL|_EN_DIVZERO|_EN_INVALID,PetscDefaultFPTrap,_ABORT_ON_ERROR,0);
267:   else                          handle_sigfpes(_OFF,_EN_OVERFL|_EN_DIVZERO|_EN_INVALID,0,_ABORT_ON_ERROR,0);

269:   _trapmode = flag;
270:   return(0);
271: }
272: /*----------------------------------------------- --------------------------------------------*/
273: /* In "fast" mode, floating point traps are imprecise and ignored.
274:    This is the reason for the fptrap(FP_TRAP_SYNC) call */
275: #elif defined(PETSC_HAVE_RS6000_STYLE_FPTRAP)
276: struct sigcontext;
277: #include <fpxcp.h>
278: #include <fptrap.h>
279: #define FPE_FLTOPERR_TRAP (fptrap_t)(0x20000000)
280: #define FPE_FLTOVF_TRAP   (fptrap_t)(0x10000000)
281: #define FPE_FLTUND_TRAP   (fptrap_t)(0x08000000)
282: #define FPE_FLTDIV_TRAP   (fptrap_t)(0x04000000)
283: #define FPE_FLTINEX_TRAP  (fptrap_t)(0x02000000)

285: static struct { int code_no; char *name; } error_codes[] = {
286:   {FPE_FLTOPERR_TRAP   ,"IEEE operand error" },
287:   { FPE_FLTOVF_TRAP    ,"floating point overflow" },
288:   { FPE_FLTUND_TRAP    ,"floating point underflow" },
289:   { FPE_FLTDIV_TRAP    ,"floating point divide" },
290:   { FPE_FLTINEX_TRAP   ,"inexact floating point result" },
291:   { 0                  ,"unknown error" }
292: } ;
293: #define SIGPC(scp) (0) /* Info MIGHT be in scp->sc_jmpbuf.jmp_context.iar */
294: /*
295:    For some reason, scp->sc_jmpbuf does not work on the RS6000, even though
296:    it looks like it should from the include definitions.  It is probably
297:    some strange interaction with the "POSIX_SOURCE" that we require.
298: */

302: void PetscDefaultFPTrap(int sig,int code,struct sigcontext *scp)
303: {
305:   int            err_ind,j;
306:   fp_ctx_t       flt_context;

309:   fp_sh_trap_info(scp,&flt_context);

311:   err_ind = -1;
312:   for (j = 0; error_codes[j].code_no; j++) {
313:     if (error_codes[j].code_no == flt_context.trap) err_ind = j;
314:   }

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

319:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
320:   MPI_Abort(PETSC_COMM_WORLD,0);
321: }

325: PetscErrorCode PetscSetFPTrap(PetscFPTrap on)
326: {
328:   if (on == PETSC_FP_TRAP_ON) {
329:     signal(SIGFPE,(void (*)(int))PetscDefaultFPTrap);
330:     fp_trap(FP_TRAP_SYNC);
331:     fp_enable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW);
332:     /* fp_enable(mask) for individual traps.  Values are:
333:        TRP_INVALID
334:        TRP_DIV_BY_ZERO
335:        TRP_OVERFLOW
336:        TRP_UNDERFLOW
337:        TRP_INEXACT
338:        Can OR then together.
339:        fp_enable_all(); for all traps.
340:     */
341:   } else {
342:     signal(SIGFPE,SIG_DFL);
343:     fp_disable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW);
344:     fp_trap(FP_TRAP_OFF);
345:   }
346:   _trapmode = on;
347:   return(0);
348: }

350: #elif defined(PETSC_HAVE_FENV_H) && !defined(__cplusplus)
351: /*
352:    C99 style floating point environment.

354:    Note that C99 merely specifies how to save, restore, and clear the floating
355:    point environment as well as defining an enumeration of exception codes.  In
356:    particular, C99 does not specify how to make floating point exceptions raise
357:    a signal.  Glibc offers this capability through FE_NOMASK_ENV (or with finer
358:    granularity, feenableexcept()), xmmintrin.h offers _MM_SET_EXCEPTION_MASK().
359: */
360: #include <fenv.h>
361: typedef struct {int code; const char *name;} FPNode;
362: static const FPNode error_codes[] = {
363:   {FE_DIVBYZERO,"divide by zero"},
364:   {FE_INEXACT,  "inexact floating point result"},
365:   {FE_INVALID,  "invalid floating point arguments (domain error)"},
366:   {FE_OVERFLOW, "floating point overflow"},
367:   {FE_UNDERFLOW,"floating point underflow"},
368:   {0           ,"unknown error"}
369: };

373: void PetscDefaultFPTrap(int sig)
374: {
375:   const FPNode *node;
376:   int          code;
377:   PetscBool    matched = PETSC_FALSE;

380:   /* Note: While it is possible for the exception state to be preserved by the
381:    * kernel, this seems to be rare which makes the following flag testing almost
382:    * useless.  But on a system where the flags can be preserved, it would provide
383:    * more detail.
384:    */
385:   code = fetestexcept(FE_ALL_EXCEPT);
386:   for (node=&error_codes[0]; node->code; node++) {
387:     if (code & node->code) {
388:       matched = PETSC_TRUE;
389:       (*PetscErrorPrintf)("*** floating point error \"%s\" occurred ***\n",node->name);
390:       code &= ~node->code; /* Unset this flag since it has been processed */
391:     }
392:   }
393:   if (!matched || code) { /* If any remaining flags are set, or we didn't process any flags */
394:     (*PetscErrorPrintf)("*** unknown floating point error occurred ***\n");
395:     (*PetscErrorPrintf)("The specific exception can be determined by running in a debugger.  When the\n");
396:     (*PetscErrorPrintf)("debugger traps the signal, the exception can be found with fetestexcept(0x%x)\n",FE_ALL_EXCEPT);
397:     (*PetscErrorPrintf)("where the result is a bitwise OR of the following flags:\n");
398:     (*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);
399:   }

401:   (*PetscErrorPrintf)("Try option -start_in_debugger\n");
402: #if defined(PETSC_USE_DEBUG)
403:   if (!PetscStackActive()) (*PetscErrorPrintf)("  or try option -log_stack\n");
404:   else {
405:     (*PetscErrorPrintf)("likely location of problem given in stack below\n");
406:     (*PetscErrorPrintf)("---------------------  Stack Frames ------------------------------------\n");
407:     PetscStackView(PETSC_STDOUT);
408:   }
409: #endif
410: #if !defined(PETSC_USE_DEBUG)
411:   (*PetscErrorPrintf)("configure using --with-debugging=yes, recompile, link, and run \n");
412:   (*PetscErrorPrintf)("with -start_in_debugger to get more information on the crash.\n");
413: #endif
414:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_INITIAL,"trapped floating point error");
415:   MPI_Abort(PETSC_COMM_WORLD,0);
416: }

420: PetscErrorCode  PetscSetFPTrap(PetscFPTrap on)
421: {
423:   if (on == PETSC_FP_TRAP_ON) {
424:     /* Clear any flags that are currently set so that activating trapping will not immediately call the signal handler. */
425:     if (feclearexcept(FE_ALL_EXCEPT)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Cannot clear floating point exception flags\n");
426: #if defined FE_NOMASK_ENV
427:     /* We could use fesetenv(FE_NOMASK_ENV), but that causes spurious exceptions (like gettimeofday() -> PetscLogDouble). */
428:     if (feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) == -1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Cannot activate floating point exceptions\n");
429: #elif defined PETSC_HAVE_XMMINTRIN_H
430:     _MM_SET_EXCEPTION_MASK(_MM_MASK_INEXACT);
431: #else
432:     /* C99 does not provide a way to modify the environment so there is no portable way to activate trapping. */
433: #endif
434:     if (SIG_ERR == signal(SIGFPE,PetscDefaultFPTrap)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Can't set floating point handler\n");
435:   } else {
436:     if (fesetenv(FE_DFL_ENV)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Cannot disable floating point exceptions");
437:     if (SIG_ERR == signal(SIGFPE,SIG_DFL)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Can't clear floating point handler\n");
438:   }
439:   _trapmode = on;
440:   return(0);
441: }

443: /* -------------------------Default -----------------------------------*/
444: #else

448: void PetscDefaultFPTrap(int sig)
449: {
451:   (*PetscErrorPrintf)("*** floating point error occurred ***\n");
452:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
453:   MPI_Abort(PETSC_COMM_WORLD,0);
454: }

458: PetscErrorCode  PetscSetFPTrap(PetscFPTrap on)
459: {
461:   if (on == PETSC_FP_TRAP_ON) {
462:     if (SIG_ERR == signal(SIGFPE,PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't set floatingpoint handler\n");
463:   } else if (SIG_ERR == signal(SIGFPE,SIG_DFL))       (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");

465:   _trapmode = on;
466:   return(0);
467: }
468: #endif