[OpenMP] Fix a small few issues

[jlpeyton]

Summary

• Add comment to help ensure new construct data are added in two places
• Check for division by zero in the loop worksharing code
• Check for syntax errors in par-range parsing

[AndreyChurbanov]

LGTM

openmp/runtime/src/kmp.h

__kmp_mm_mwait(unsigned extensions, unsigned hints) {
   _mm_mwait(extensions, hints);
 }
 #endif // KMP_HAVE_UMWAIT
 
 /* ------------------------------------------------------------------------ */
 /* Support datatypes for the orphaned construct nesting checks.             */
 /* ------------------------------------------------------------------------ */
 
+/* When adding to this enum, add its corresponding string in cons_text_c[]
+ * array in kmp_error.cpp */
 enum cons_type {
   ct_none,
   ct_parallel,
   ct_pdo,
   ct_pdo_ordered,
   ct_psections,
   ct_psingle,
   ct_critical,

openmp/runtime/src/kmp_dispatch.cpp

#if KMP_USE_X87CONTROL
            expected to impact the correctness of the algorithm, but this has not
            been mathematically proven. */
         // save original FPCW and set precision to 64-bit, as
         // Windows* OS on IA-32 architecture defaults to 53-bit
         unsigned int oldFpcw = _control87(0, 0);
         _control87(_PC_64, _MCW_PC); // 0,0x30000
 #endif
         /* value used for comparison in solver for cross-over point */
+        KMP_ASSERT(tc > 0);
         long double target = ((long double)chunk * 2 + 1) * nproc / tc;
 
         /* crossover point--chunk indexes equal to or greater than
            this point switch to dynamic-style scheduling */
         UT cross;
 
         /* commonly used term: (2 nproc - 1)/(2 nproc) */
         x = 1.0 - 0.5 / (double)nproc;
case kmp_sch_guided_simd: {
     while (1) {
       ST remaining; // signed, because can be < 0
       init = sh->u.s.iteration; // shared value
       remaining = trip - init;
       if (remaining <= 0) { // AC: need to compare with 0 first
         status = 0; // nothing to do, don't try atomic op
         break;
       }
-      KMP_DEBUG_ASSERT(init % chunk == 0);
+      KMP_DEBUG_ASSERT(chunk && init % chunk == 0);
       // compare with K*nproc*(chunk+1), K=2 by default
       if ((T)remaining < pr->u.p.parm2) {
         // use dynamic-style schedule
         // atomically increment iterations, get old value
         init = test_then_add<ST>(RCAST(volatile ST *, &sh->u.s.iteration),
                                  (ST)chunk);
         remaining = trip - init;
         if (remaining <= 0) {

openmp/runtime/src/kmp_settings.cpp

 
 #ifdef KMP_DEBUG
 static char *par_range_to_print = NULL;
 
 static void __kmp_stg_parse_par_range(char const *name, char const *value,
                                       int *out_range, char *out_routine,
                                       char *out_file, int *out_lb,
                                       int *out_ub) {
+  const char *par_range_value;
   size_t len = KMP_STRLEN(value) + 1;
   par_range_to_print = (char *)KMP_INTERNAL_MALLOC(len + 1);
   KMP_STRNCPY_S(par_range_to_print, len + 1, value, len + 1);
   __kmp_par_range = +1;
   __kmp_par_range_lb = 0;
   __kmp_par_range_ub = INT_MAX;
   for (;;) {
     unsigned int len;
-    if (*value == '\0') {
+    if (!value || *value == '\0') {
       break;
     }
     if (!__kmp_strcasecmp_with_sentinel("routine", value, '=')) {
-      value = strchr(value, '=') + 1;
+      par_range_value = strchr(value, '=') + 1;
+      if (!par_range_value)
+        goto par_range_error;
+      value = par_range_value;
       len = __kmp_readstr_with_sentinel(out_routine, value,
                                         KMP_PAR_RANGE_ROUTINE_LEN - 1, ',');
       if (len == 0) {
         goto par_range_error;
       }
       value = strchr(value, ',');
       if (value != NULL) {
         value++;
       }
       continue;
     }
     if (!__kmp_strcasecmp_with_sentinel("filename", value, '=')) {
-      value = strchr(value, '=') + 1;
+      par_range_value = strchr(value, '=') + 1;
+      if (!par_range_value)
+        goto par_range_error;
+      value = par_range_value;
       len = __kmp_readstr_with_sentinel(out_file, value,
                                         KMP_PAR_RANGE_FILENAME_LEN - 1, ',');
       if (len == 0) {
         goto par_range_error;
       }
       value = strchr(value, ',');
       if (value != NULL) {
         value++;
       }
       continue;
     }
     if ((!__kmp_strcasecmp_with_sentinel("range", value, '=')) ||
         (!__kmp_strcasecmp_with_sentinel("incl_range", value, '='))) {
-      value = strchr(value, '=') + 1;
+      par_range_value = strchr(value, '=') + 1;
+      if (!par_range_value)
+        goto par_range_error;
+      value = par_range_value;
       if (KMP_SSCANF(value, "%d:%d", out_lb, out_ub) != 2) {
         goto par_range_error;
       }
       *out_range = +1;
       value = strchr(value, ',');
       if (value != NULL) {
         value++;
       }
       continue;
     }
     if (!__kmp_strcasecmp_with_sentinel("excl_range", value, '=')) {
-      value = strchr(value, '=') + 1;
+      par_range_value = strchr(value, '=') + 1;
+      if (!par_range_value)
+        goto par_range_error;
+      value = par_range_value;
       if (KMP_SSCANF(value, "%d:%d", out_lb, out_ub) != 2) {
         goto par_range_error;
       }
       *out_range = -1;
       value = strchr(value, ',');
       if (value != NULL) {
         value++;
       }