[flang-commits] [flang] [flang][OpenMP] Issue a warning when parsing future directive spelling (PR #147765)

[Jack Styles via flang-commits]

================
@@ -259,6 +259,57 @@ void OmpStructureChecker::CheckVariableListItem(
   }
 }
 
+void OmpStructureChecker::CheckDirectiveSpelling(
+    parser::CharBlock spelling, llvm::omp::Directive id) {
+  // Directive names that contain spaces can be spelled in the source without
+  // any of the spaces. Because of that getOpenMPKind* is not guaranteed to
+  // work with the source spelling as the argument.
+  //
+  // To verify the source spellings, we have to get the spelling for a given
+  // version, remove spaces and compare it with the source spelling (also
+  // with spaces removed).
+  auto removeSpaces = [](llvm::StringRef s) {
+    std::string n{s.str()};
+    for (size_t idx{n.size()}; idx > 0; --idx) {
+      if (isspace(n[idx - 1])) {
+        n.erase(idx - 1, 1);
+      }
+    }
+    return n;
+  };
+
+  std::string lowerNoWS{removeSpaces(
+      parser::ToLowerCaseLetters({spelling.begin(), spelling.size()}))};
+  llvm::StringRef ref(lowerNoWS);
+  if (ref.starts_with("end")) {
+    ref = ref.drop_front(3);
+  }
+
+  unsigned version{context_.langOptions().OpenMPVersion};
+
+  // For every "future" version v, check if the check if the corresponding
+  // spelling of id was introduced later than the current version. If so,
+  // and if that spelling matches the source spelling, issue a warning.
+  for (unsigned v : llvm::omp::getOpenMPVersions()) {
+    if (v <= version) {
+      continue;
+    }
+    llvm::StringRef name{llvm::omp::getOpenMPDirectiveName(id, v)};
+    auto [kind, versions]{llvm::omp::getOpenMPDirectiveKindAndVersions(name)};
+    assert(kind == id && "Directive kind mismatch");
+
+    if (static_cast<int>(version) >= versions.Min) {
+      continue;
+    }
+    if (ref == removeSpaces(name)) {
+      context_.Say(spelling,
----------------
Stylie777 wrote:

What is the potential impact if we make this an error? I understand some users programs may no longer compile but they should be using the correct spelling for the version of OpenMP they intend to use - but I feel this may be worth considering.

https://github.com/llvm/llvm-project/pull/147765