Actual source code: fp.c
petsc-3.10.5 2019-03-28
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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