Date: 2026-07-30T21:14:24+00:00

Actual source code: checkptr.c

      1: #include <petsc/private/petscimpl.h>

      3: static PetscInt petsc_checkpointer_intensity = 1;

      5: /*@
      6:   PetscCheckPointerSetIntensity - Set the intensity of debug pointer checks

      8:   Not Collective

     10:   Input Parameter:
     11: . intensity - how much to check pointers for validity

     13:   Options Database Key:
     14: . -check_pointer_intensity - intensity (0, 1, or 2)

     16:   Level: advanced

     18:   Notes:
     19:   An intense pointer check registers a signal handler and attempts to dereference to confirm
     20:   whether the address is valid.  An intensity of 0 never uses signal handlers, 1 uses them when
     21:   not in a "hot" function, and intensity of 2 always uses a signal handler.

     23: .seealso: `PetscCheckPointer()`, `PetscFunctionBeginHot()`
     24: @*/
     25: PetscErrorCode PetscCheckPointerSetIntensity(PetscInt intensity)
     26: {
     27:   PetscFunctionBegin;
     28:   PetscCheck((intensity >= 0) && (intensity <= 2), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Intensity %" PetscInt_FMT " not in [0,2]", intensity);
     29:   petsc_checkpointer_intensity = intensity;
     30:   PetscFunctionReturn(PETSC_SUCCESS);
     31: }

     33: #if PetscDefined(HAVE_SETJMP_H)
     34:   #include <setjmp.h>
     35: static jmp_buf   PetscSegvJumpBuf;
     36: static PetscBool PetscSegvJumpBuf_set;

     38: /*@C
     39:   PetscSignalSegvCheckPointerOrMpi - To be called from a signal handler for SIGSEGV.

     41:   Not Collective, No Fortran Support

     43:   Level: developer

     45:   Note:
     46:   If the signal was received while executing `PetscCheckPointer()`, this function longjmps back
     47:   there, otherwise it returns with no effect. This function is called automatically by
     48:   `PetscSignalHandlerDefault()`.

     50: .seealso: `PetscPushSignalHandler()`
     51: @*/
     52: void PetscSignalSegvCheckPointerOrMpi(void)
     53: {
     54:   if (PetscSegvJumpBuf_set) longjmp(PetscSegvJumpBuf, 1);
     55: }

     57: /*@C
     58:   PetscCheckPointer - Returns `PETSC_TRUE` if a pointer points to accessible data

     60:   Not Collective, No Fortran Support

     62:   Input Parameters:
     63: + ptr   - the pointer
     64: - dtype - the type of data the pointer is suppose to point to

     66:   Level: developer

     68:   Notes:
     69:   This is a non-standard PETSc function in that it returns the result and does not return an error code.

     71:   This function always returns true when running under Valgrind, or when compiled with asan options.

     73: .seealso: `PetscCheckPointerSetIntensity()`
     74: @*/
     75: PetscBool PetscCheckPointer(const void *ptr, PetscDataType dtype)
     76: {
     77:   if (PETSC_RUNNING_ON_VALGRIND) return PETSC_TRUE;
     78:   if (!ptr) return PETSC_FALSE;
     79:   if (petsc_checkpointer_intensity < 1) return PETSC_TRUE;
     80:   if (PetscDefined(HAVE_SANITIZER)) return PETSC_TRUE;

     82:   #if PetscDefined(USE_DEBUG) && !PetscDefined(HAVE_THREADSAFETY)
     83:   /* Skip the verbose check if we are inside a hot function. */
     84:   if (petscstack.hotdepth > 0 && petsc_checkpointer_intensity < 2) return PETSC_TRUE;
     85:   #endif

     87:   PetscSegvJumpBuf_set = PETSC_TRUE;

     89:   if (setjmp(PetscSegvJumpBuf)) {
     90:     /* A segv was triggered in the code below hence we return with an error code */
     91:     PetscSegvJumpBuf_set = PETSC_FALSE;
     92:     return PETSC_FALSE;
     93:   } else {
     94:     switch (dtype) {
     95:     case PETSC_INT: {
     96:       PETSC_UNUSED PetscInt x = *(volatile PetscInt *)ptr;
     97:       break;
     98:     }
     99:   #if defined(PETSC_USE_COMPLEX)
    100:     case PETSC_SCALAR: { /* C++ is seriously dysfunctional with volatile std::complex. */
    101:     #if defined(PETSC_USE_CXXCOMPLEX)
    102:       PetscReal                         xreal = ((volatile PetscReal *)ptr)[0], ximag = ((volatile PetscReal *)ptr)[1];
    103:       PETSC_UNUSED volatile PetscScalar x = xreal + PETSC_i * ximag;
    104:     #else
    105:       PETSC_UNUSED PetscScalar x = *(volatile PetscScalar *)ptr;
    106:     #endif
    107:       break;
    108:     }
    109:   #endif
    110:     case PETSC_REAL: {
    111:       PETSC_UNUSED PetscReal x = *(volatile PetscReal *)ptr;
    112:       break;
    113:     }
    114:     case PETSC_BOOL: {
    115:       PETSC_UNUSED PetscBool x = *(volatile PetscBool *)ptr;
    116:       break;
    117:     }
    118:     case PETSC_ENUM: {
    119:       PETSC_UNUSED PetscEnum x = *(volatile PetscEnum *)ptr;
    120:       break;
    121:     }
    122:     case PETSC_CHAR: {
    123:       PETSC_UNUSED char x = *(volatile char *)ptr;
    124:       break;
    125:     }
    126:     case PETSC_OBJECT: {
    127:       PETSC_UNUSED volatile PetscClassId classid = ((PetscObject)ptr)->classid;
    128:       break;
    129:     }
    130:     default:;
    131:     }
    132:   }
    133:   PetscSegvJumpBuf_set = PETSC_FALSE;
    134:   return PETSC_TRUE;
    135: }
    136: #endif