[nfc][flang] Eliminate the dependency on cctype by using characters.h

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D148076

Author: Shao-Ce SUN

flang/include/flang/Parser/characters.h

@@ -58,6 +58,13 @@ inline constexpr bool IsLegalInIdentifier(char ch) {
   return IsLegalIdentifierStart(ch) || IsDecimalDigit(ch);
 }
 
+inline constexpr bool IsPrintable(char ch) { return ch >= ' ' && ch <= '~'; }
+
+inline constexpr bool IsWhiteSpace(char ch) {
+  return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\v' || ch == '\f' ||
+      ch == '\r';
+}
+
 inline constexpr char ToLowerCaseLetter(char ch) {
   return IsUpperCaseLetter(ch) ? ch - 'A' + 'a' : ch;
 }

flang/lib/Parser/token-parsers.h

@@ -19,7 +19,6 @@
 #include "flang/Parser/characters.h"
 #include "flang/Parser/instrumented-parser.h"
 #include "flang/Parser/provenance.h"
-#include <cctype>
 #include <cstddef>
 #include <cstring>
 #include <functional>
@@ -526,7 +525,7 @@ struct HollerithLiteral {
       int chBytes{UTF_8CharacterBytes(state.GetLocation())};
       for (int bytes{chBytes}; bytes > 0; --bytes) {
         if (std::optional<const char *> at{nextCh.Parse(state)}) {
-          if (chBytes == 1 && !std::isprint(**at)) {
+          if (chBytes == 1 && !IsPrintable(**at)) {
             state.Say(start, "Bad character in Hollerith"_err_en_US);
             return std::nullopt;
           }

flang/lib/Semantics/resolve-labels.cpp

@@ -11,7 +11,6 @@
 #include "flang/Common/template.h"
 #include "flang/Parser/parse-tree-visitor.h"
 #include "flang/Semantics/semantics.h"
-#include <cctype>
 #include <cstdarg>
 #include <type_traits>
 
@@ -926,7 +925,7 @@ parser::CharBlock SkipLabel(const parser::CharBlock &position) {
     std::size_t i{1l};
     for (; (i < maxPosition) && parser::IsDecimalDigit(position[i]); ++i) {
     }
-    for (; (i < maxPosition) && std::isspace(position[i]); ++i) {
+    for (; (i < maxPosition) && parser::IsWhiteSpace(position[i]); ++i) {
     }
     return parser::CharBlock{position.begin() + i, position.end()};
   }