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

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

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

 43:   Not Collective

 45:   Level: developer

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

 52: .seealso: `PetscPushSignalHandler()`
 53: @*/
 54: void PetscSignalSegvCheckPointerOrMpi(void)
 55: {
 56:   if (PetscSegvJumpBuf_set) longjmp(PetscSegvJumpBuf, 1);
 57: }

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

 62:   Not Collective

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

 68:   Level: developer

 70:   Note:
 71:   This is a non-standard PETSc function in that it returns the result and does not return an error code

 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;

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

 86:   PetscSegvJumpBuf_set = PETSC_TRUE;

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