[OpenMP][libomp] Allow white spcaes in OMP_TARGET_OFFLOAD value

[hbae]

Summary

Remove heading/trailing white spaces when matching OMP_TARGET_OFFLOAD
value.

[jdoerfert]

Do we trim any other option? I am confused by this.

[hbae]

In D149890#4320949, @jdoerfert wrote:

Do we trim any other option? I am confused by this.

Some options have their own logic to skip white spaces, but not all option values are handled like that.

So, your question is why we don't do this for other options?

[jlpeyton]

@jdoerfert , to reiterate what @hbae said, the trimming functionality is there for almost all (if not all) the environment variable parsing routines. It's seen mostly with the SKIP_WS() macro and manual manipulations of char* next, scan. The kmp_trimmed_str_t is supposed to just make it a bit simpler, especially for the case of a one-token environment variable. Is it the way the trimming is performed that you don't like?

[jdoerfert]

typo: spcaes

LG, all I tried to say is that we should be consistent across env vars. Accepting whitespaces around stuff is probably the right choice.

openmp/runtime/src/kmp_settings.cpp

 }; // struct __kmp_stg_fr_data
 
 static int __kmp_stg_check_rivals( // 0 -- Ok, 1 -- errors found.
     char const *name, // Name of variable.
     char const *value, // Value of the variable.
     kmp_setting_t **rivals // List of rival settings (must include current one).
 );
 
+// Helper struct that trims heading/trailing white spaces
+struct kmp_trimmed_str_t {
+  kmp_str_buf_t buf;
+  kmp_trimmed_str_t(const char *str) {
+    __kmp_str_buf_init(&buf);
+    size_t len = KMP_STRLEN(str);
+    if (len == 0)
+      return;
+    const char *begin = str;
+    const char *end = str + KMP_STRLEN(str) - 1;
+    SKIP_WS(begin);
+    while (begin < end && *end == ' ')
+      end--;
+    __kmp_str_buf_cat(&buf, begin, end - begin + 1);
+  }
+  ~kmp_trimmed_str_t() { __kmp_str_buf_free(&buf); }
+  const char *get() { return buf.str; }
+};
+
 // -----------------------------------------------------------------------------
 // Helper parse functions.
 
 static void __kmp_stg_parse_bool(char const *name, char const *value,
                                  int *out) {
   if (__kmp_str_match_true(value)) {
     *out = TRUE;
   } else if (__kmp_str_match_false(value)) {
static void __kmp_stg_print_default_device(kmp_str_buf_t *buffer,
                                            char const *name, void *data) {
   __kmp_stg_print_int(buffer, name, __kmp_default_device);
 } // __kmp_stg_print_default_device
 
 // -----------------------------------------------------------------------------
 // OpenMP 5.0: OMP_TARGET_OFFLOAD
 static void __kmp_stg_parse_target_offload(char const *name, char const *value,
                                            void *data) {
-  const char *next = value;
-  const char *scan = next;
-
+  kmp_trimmed_str_t value_str(value);
+  const char *scan = value_str.get();
   __kmp_target_offload = tgt_default;
-  SKIP_WS(next);
-  if (*next == '\0')
+
+  if (*scan == '\0')
     return;
-  scan = next;
+
   if (!__kmp_strcasecmp_with_sentinel("mandatory", scan, 0)) {
     __kmp_target_offload = tgt_mandatory;
   } else if (!__kmp_strcasecmp_with_sentinel("disabled", scan, 0)) {
     __kmp_target_offload = tgt_disabled;
   } else if (!__kmp_strcasecmp_with_sentinel("default", scan, 0)) {
     __kmp_target_offload = tgt_default;
   } else {
     KMP_WARNING(SyntaxErrorUsing, name, "DEFAULT");
   }
-
 } // __kmp_stg_parse_target_offload
 
 static void __kmp_stg_print_target_offload(kmp_str_buf_t *buffer,
                                            char const *name, void *data) {
   const char *value = NULL;
   if (__kmp_target_offload == tgt_default)
     value = "DEFAULT";
   else if (__kmp_target_offload == tgt_mandatory)