Actual source code: fp.c

petsc-master 2017-04-28
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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>
 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 */

 29: /*@
 30:    PetscFPTrapPush - push a floating point trapping mode, to be restored using PetscFPTrapPop()

 32:    Not Collective

 34:    Input Arguments:
 35: . trap - PETSC_FP_TRAP_ON or PETSC_FP_TRAP_OFF

 37:    Level: advanced

 39: .seealso: PetscFPTrapPop(), PetscSetFPTrap()
 40: @*/
 41: PetscErrorCode PetscFPTrapPush(PetscFPTrap trap)
 42: {
 43:   PetscErrorCode         ierr;
 44:   struct PetscFPTrapLink *link;

 47:   PetscNew(&link);
 48:   link->trapmode = _trapmode;
 49:   link->next     = _trapstack;
 50:   _trapstack     = link;
 51:   if (trap != _trapmode) {PetscSetFPTrap(trap);}
 52:   return(0);
 53: }

 55: /*@
 56:    PetscFPTrapPop - push a floating point trapping mode, to be restored using PetscFPTrapPop()

 58:    Not Collective

 60:    Level: advanced

 62: .seealso: PetscFPTrapPush(), PetscSetFPTrap()
 63: @*/
 64: PetscErrorCode PetscFPTrapPop(void)
 65: {
 66:   PetscErrorCode         ierr;
 67:   struct PetscFPTrapLink *link;

 70:   if (_trapstack->trapmode != _trapmode) {PetscSetFPTrap(_trapstack->trapmode);}
 71:   link       = _trapstack;
 72:   _trapstack = _trapstack->next;
 73:   PetscFree(link);
 74:   return(0);
 75: }

 77: /*--------------------------------------- ---------------------------------------------------*/
 78: #if defined(PETSC_HAVE_SUN4_STYLE_FPTRAP)
 79: #include <floatingpoint.h>

 81: PETSC_EXTERN PetscErrorCode ieee_flags(char*,char*,char*,char**);
 82: PETSC_EXTERN PetscErrorCode ieee_handler(char*,char*,sigfpe_handler_type(int,int,struct sigcontext*,char*));

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

 95: sigfpe_handler_type PetscDefaultFPTrap(int sig,int code,struct sigcontext *scp,char *addr)
 96: {
 98:   int            err_ind = -1,j;

101:   for (j = 0; error_codes[j].code_no; j++) {
102:     if (error_codes[j].code_no == code) err_ind = j;
103:   }

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

108:   PetscError(PETSC_COMM_SELF,PETSC_ERR_FP,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
109:   MPI_Abort(PETSC_COMM_WORLD,0);
110:   return(0);
111: }

113: /*@
114:    PetscSetFPTrap - Enables traps/exceptions on common floating point errors.
115:                     This option may not work on certain machines.

117:    Not Collective

119:    Input Parameters:
120: .  flag - PETSC_FP_TRAP_ON, PETSC_FP_TRAP_OFF.

122:    Options Database Keys:
123: .  -fp_trap - Activates floating point trapping

125:    Level: advanced

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

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

142:    Caution:
143:    On certain machines, in particular the IBM rs6000, floating point
144:    trapping is VERY slow!

146:    Concepts: floating point exceptions^trapping
147:    Concepts: divide by zero

149: .seealso: PetscFPTrapPush(), PetscFPTrapPop()
150: @*/
151: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
152: {
153:   char *out;

156:   /* Clear accumulated exceptions.  Used to suppress meaningless messages from f77 programs */
157:   (void) ieee_flags("clear","exception","all",&out);
158:   if (flag == PETSC_FP_TRAP_ON) {
159:     /*
160:       To trap more fp exceptions, including underflow, change the line below to
161:       if (ieee_handler("set","all",PetscDefaultFPTrap)) {
162:     */
163:     if (ieee_handler("set","common",PetscDefaultFPTrap))        (*PetscErrorPrintf)("Can't set floatingpoint handler\n");
164:   } else if (ieee_handler("clear","common",PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");

166:   _trapmode = flag;
167:   return(0);
168: }

170: /* -------------------------------------------------------------------------------------------*/
171: #elif defined(PETSC_HAVE_SOLARIS_STYLE_FPTRAP)
172: #include <sunmath.h>
173: #include <floatingpoint.h>
174: #include <siginfo.h>
175: #include <ucontext.h>

177: static struct { int code_no; char *name; } error_codes[] = {
178:   { FPE_FLTINV,"invalid floating point operand"},
179:   { FPE_FLTRES,"inexact floating point result"},
180:   { FPE_FLTDIV,"division-by-zero"},
181:   { FPE_FLTUND,"floating point underflow"},
182:   { FPE_FLTOVF,"floating point overflow"},
183:   { 0,         "unknown error"}
184: };
185: #define SIGPC(scp) (scp->si_addr)

187: void PetscDefaultFPTrap(int sig,siginfo_t *scp,ucontext_t *uap)
188: {
189:   int            err_ind,j,code = scp->si_code;

193:   err_ind = -1;
194:   for (j = 0; error_codes[j].code_no; j++) {
195:     if (error_codes[j].code_no == code) err_ind = j;
196:   }

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

201:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
202:   MPI_Abort(PETSC_COMM_WORLD,0);
203: }

205: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
206: {
207:   char *out;

210:   /* Clear accumulated exceptions.  Used to suppress meaningless messages from f77 programs */
211:   (void) ieee_flags("clear","exception","all",&out);
212:   if (flag == PETSC_FP_TRAP_ON) {
213:     if (ieee_handler("set","common",(sigfpe_handler_type)PetscDefaultFPTrap))        (*PetscErrorPrintf)("Can't set floating point handler\n");
214:   } else if (ieee_handler("clear","common",(sigfpe_handler_type)PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");
215:   _trapmode = flag;
216:   return(0);
217: }

219: /* ------------------------------------------------------------------------------------------*/

221: #elif defined(PETSC_HAVE_IRIX_STYLE_FPTRAP)
222: #include <sigfpe.h>
223: static struct { int code_no; char *name; } error_codes[] = {
224:   { _INVALID   ,"IEEE operand error" },
225:   { _OVERFL    ,"floating point overflow" },
226:   { _UNDERFL   ,"floating point underflow" },
227:   { _DIVZERO   ,"floating point divide" },
228:   { 0          ,"unknown error" }
229: } ;
230: void PetscDefaultFPTrap(unsigned exception[],int val[])
231: {
232:   int err_ind,j,code;

235:   code    = exception[0];
236:   err_ind = -1;
237:   for (j = 0; error_codes[j].code_no; j++) {
238:     if (error_codes[j].code_no == code) err_ind = j;
239:   }
240:   if (err_ind >= 0) (*PetscErrorPrintf)("*** %s occurred ***\n",error_codes[err_ind].name);
241:   else              (*PetscErrorPrintf)("*** floating point error 0x%x occurred ***\n",code);

243:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
244:   MPI_Abort(PETSC_COMM_WORLD,0);
245: }

247: PetscErrorCode PetscSetFPTrap(PetscFPTrap flag)
248: {
250:   if (flag == PETSC_FP_TRAP_ON) handle_sigfpes(_ON,_EN_OVERFL|_EN_DIVZERO|_EN_INVALID,PetscDefaultFPTrap,_ABORT_ON_ERROR,0);
251:   else                          handle_sigfpes(_OFF,_EN_OVERFL|_EN_DIVZERO|_EN_INVALID,0,_ABORT_ON_ERROR,0);

253:   _trapmode = flag;
254:   return(0);
255: }
256: /*----------------------------------------------- --------------------------------------------*/
257: /* In "fast" mode, floating point traps are imprecise and ignored.
258:    This is the reason for the fptrap(FP_TRAP_SYNC) call */
259: #elif defined(PETSC_HAVE_RS6000_STYLE_FPTRAP)
260: struct sigcontext;
261: #include <fpxcp.h>
262: #include <fptrap.h>
263: #define FPE_FLTOPERR_TRAP (fptrap_t)(0x20000000)
264: #define FPE_FLTOVF_TRAP   (fptrap_t)(0x10000000)
265: #define FPE_FLTUND_TRAP   (fptrap_t)(0x08000000)
266: #define FPE_FLTDIV_TRAP   (fptrap_t)(0x04000000)
267: #define FPE_FLTINEX_TRAP  (fptrap_t)(0x02000000)

269: static struct { int code_no; char *name; } error_codes[] = {
270:   {FPE_FLTOPERR_TRAP   ,"IEEE operand error" },
271:   { FPE_FLTOVF_TRAP    ,"floating point overflow" },
272:   { FPE_FLTUND_TRAP    ,"floating point underflow" },
273:   { FPE_FLTDIV_TRAP    ,"floating point divide" },
274:   { FPE_FLTINEX_TRAP   ,"inexact floating point result" },
275:   { 0                  ,"unknown error" }
276: } ;
277: #define SIGPC(scp) (0) /* Info MIGHT be in scp->sc_jmpbuf.jmp_context.iar */
278: /*
279:    For some reason, scp->sc_jmpbuf does not work on the RS6000, even though
280:    it looks like it should from the include definitions.  It is probably
281:    some strange interaction with the "POSIX_SOURCE" that we require.
282: */

284: void PetscDefaultFPTrap(int sig,int code,struct sigcontext *scp)
285: {
287:   int            err_ind,j;
288:   fp_ctx_t       flt_context;

291:   fp_sh_trap_info(scp,&flt_context);

293:   err_ind = -1;
294:   for (j = 0; error_codes[j].code_no; j++) {
295:     if (error_codes[j].code_no == flt_context.trap) err_ind = j;
296:   }

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

301:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
302:   MPI_Abort(PETSC_COMM_WORLD,0);
303: }

305: PetscErrorCode PetscSetFPTrap(PetscFPTrap on)
306: {
308:   if (on == PETSC_FP_TRAP_ON) {
309:     signal(SIGFPE,(void (*)(int))PetscDefaultFPTrap);
310:     fp_trap(FP_TRAP_SYNC);
311:     fp_enable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW);
312:     /* fp_enable(mask) for individual traps.  Values are:
313:        TRP_INVALID
314:        TRP_DIV_BY_ZERO
315:        TRP_OVERFLOW
316:        TRP_UNDERFLOW
317:        TRP_INEXACT
318:        Can OR then together.
319:        fp_enable_all(); for all traps.
320:     */
321:   } else {
322:     signal(SIGFPE,SIG_DFL);
323:     fp_disable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW);
324:     fp_trap(FP_TRAP_OFF);
325:   }
326:   _trapmode = on;
327:   return(0);
328: }

330: #elif defined(PETSC_HAVE_FENV_H) && !defined(__cplusplus)
331: /*
332:    C99 style floating point environment.

334:    Note that C99 merely specifies how to save, restore, and clear the floating
335:    point environment as well as defining an enumeration of exception codes.  In
336:    particular, C99 does not specify how to make floating point exceptions raise
337:    a signal.  Glibc offers this capability through FE_NOMASK_ENV (or with finer
338:    granularity, feenableexcept()), xmmintrin.h offers _MM_SET_EXCEPTION_MASK().
339: */
340: #include <fenv.h>
341: typedef struct {int code; const char *name;} FPNode;
342: static const FPNode error_codes[] = {
343:   {FE_DIVBYZERO,"divide by zero"},
344:   {FE_INEXACT,  "inexact floating point result"},
345:   {FE_INVALID,  "invalid floating point arguments (domain error)"},
346:   {FE_OVERFLOW, "floating point overflow"},
347:   {FE_UNDERFLOW,"floating point underflow"},
348:   {0           ,"unknown error"}
349: };

351: void PetscDefaultFPTrap(int sig)
352: {
353:   const FPNode *node;
354:   int          code;
355:   PetscBool    matched = PETSC_FALSE;

358:   /* Note: While it is possible for the exception state to be preserved by the
359:    * kernel, this seems to be rare which makes the following flag testing almost
360:    * useless.  But on a system where the flags can be preserved, it would provide
361:    * more detail.
362:    */
363:   code = fetestexcept(FE_ALL_EXCEPT);
364:   for (node=&error_codes[0]; node->code; node++) {
365:     if (code & node->code) {
366:       matched = PETSC_TRUE;
367:       (*PetscErrorPrintf)("*** floating point error \"%s\" occurred ***\n",node->name);
368:       code &= ~node->code; /* Unset this flag since it has been processed */
369:     }
370:   }
371:   if (!matched || code) { /* If any remaining flags are set, or we didn't process any flags */
372:     (*PetscErrorPrintf)("*** unknown floating point error occurred ***\n");
373:     (*PetscErrorPrintf)("The specific exception can be determined by running in a debugger.  When the\n");
374:     (*PetscErrorPrintf)("debugger traps the signal, the exception can be found with fetestexcept(0x%x)\n",FE_ALL_EXCEPT);
375:     (*PetscErrorPrintf)("where the result is a bitwise OR of the following flags:\n");
376:     (*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);
377:   }

379:   (*PetscErrorPrintf)("Try option -start_in_debugger\n");
380: #if defined(PETSC_USE_DEBUG)
381:   if (!PetscStackActive()) (*PetscErrorPrintf)("  or try option -log_stack\n");
382:   else {
383:     (*PetscErrorPrintf)("likely location of problem given in stack below\n");
384:     (*PetscErrorPrintf)("---------------------  Stack Frames ------------------------------------\n");
385:     PetscStackView(PETSC_STDOUT);
386:   }
387: #endif
388: #if !defined(PETSC_USE_DEBUG)
389:   (*PetscErrorPrintf)("configure using --with-debugging=yes, recompile, link, and run \n");
390:   (*PetscErrorPrintf)("with -start_in_debugger to get more information on the crash.\n");
391: #endif
392:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_INITIAL,"trapped floating point error");
393:   MPI_Abort(PETSC_COMM_WORLD,0);
394: }

396: PetscErrorCode  PetscSetFPTrap(PetscFPTrap on)
397: {
399:   if (on == PETSC_FP_TRAP_ON) {
400:     /* Clear any flags that are currently set so that activating trapping will not immediately call the signal handler. */
401:     if (feclearexcept(FE_ALL_EXCEPT)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Cannot clear floating point exception flags\n");
402: #if defined FE_NOMASK_ENV
403:     /* We could use fesetenv(FE_NOMASK_ENV), but that causes spurious exceptions (like gettimeofday() -> PetscLogDouble). */
404:     if (feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) == -1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Cannot activate floating point exceptions\n");
405: #elif defined PETSC_HAVE_XMMINTRIN_H
406:     _MM_SET_EXCEPTION_MASK(_MM_MASK_INEXACT | _MM_MASK_UNDERFLOW);
407: #else
408:     /* C99 does not provide a way to modify the environment so there is no portable way to activate trapping. */
409: #endif
410:     if (SIG_ERR == signal(SIGFPE,PetscDefaultFPTrap)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Can't set floating point handler\n");
411:   } else {
412:     if (fesetenv(FE_DFL_ENV)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Cannot disable floating point exceptions");
413:     if (SIG_ERR == signal(SIGFPE,SIG_DFL)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Can't clear floating point handler\n");
414:   }
415:   _trapmode = on;
416:   return(0);
417: }

419: /* -------------------------Default -----------------------------------*/
420: #else

422: void PetscDefaultFPTrap(int sig)
423: {
425:   (*PetscErrorPrintf)("*** floating point error occurred ***\n");
426:   PetscError(PETSC_COMM_SELF,0,"User provided function","Unknown file",PETSC_ERR_FP,PETSC_ERROR_REPEAT,"floating point error");
427:   MPI_Abort(PETSC_COMM_WORLD,0);
428: }

430: PetscErrorCode  PetscSetFPTrap(PetscFPTrap on)
431: {
433:   if (on == PETSC_FP_TRAP_ON) {
434:     if (SIG_ERR == signal(SIGFPE,PetscDefaultFPTrap)) (*PetscErrorPrintf)("Can't set floatingpoint handler\n");
435:   } else if (SIG_ERR == signal(SIGFPE,SIG_DFL))       (*PetscErrorPrintf)("Can't clear floatingpoint handler\n");

437:   _trapmode = on;
438:   return(0);
439: }
440: #endif