[flang-commits] [flang] [llvm] [flang][OpenMP] Semantic checks for context selectors (PR #123243)

[Tom Eccles via flang-commits]

================
@@ -4537,14 +4538,513 @@ void OmpStructureChecker::Enter(const parser::OmpClause::OmpxBare &x) {
   }
 }
 
-void OmpStructureChecker::Enter(const parser::OmpContextSelector &ctxSel) {
+void OmpStructureChecker::Enter(const parser::OmpClause::When &x) {
+  CheckAllowedClause(llvm::omp::Clause::OMPC_when);
+  OmpVerifyModifiers(
+      x.v, llvm::omp::OMPC_when, GetContext().clauseSource, context_);
+}
+
+void OmpStructureChecker::Enter(const parser::OmpContextSelector &ctx) {
   EnterDirectiveNest(ContextSelectorNest);
+
+  using SetName = parser::OmpTraitSetSelectorName;
+  std::map<SetName::Value, const SetName *> visited;
+
+  for (const parser::OmpTraitSetSelector &traitSet : ctx.v) {
+    auto &name{std::get<SetName>(traitSet.t)};
+    auto [prev, unique]{visited.insert(std::make_pair(name.v, &name))};
+    if (!unique) {
+      std::string showName{parser::ToUpperCaseLetters(name.ToString())};
+      parser::MessageFormattedText txt(
+          "Repeated trait set name %s in a context specifier"_err_en_US,
+          showName);
+      parser::Message message(name.source, txt);
+      message.Attach(prev->second->source,
+          "Previous trait set %s provided here"_en_US, showName);
+      context_.Say(std::move(message));
+    }
+    CheckTraitSetSelector(traitSet);
+  }
 }
 
 void OmpStructureChecker::Leave(const parser::OmpContextSelector &) {
   ExitDirectiveNest(ContextSelectorNest);
 }
 
+std::optional<evaluate::DynamicType> OmpStructureChecker::GetDynamicType(
+    const common::Indirection<parser::Expr> &parserExpr) {
+  // Indirection<parser::Expr>      parserExpr
+  //  `- parser::Expr               ^.value()
+  const parser::TypedExpr &typedExpr{parserExpr.value().typedExpr};
+  // ForwardOwningPointer           typedExpr
+  // `- GenericExprWrapper          ^.get()
+  //    `- std::optional<Expr>      ^->v
+  if (auto maybeExpr{typedExpr.get()->v}) {
+    return maybeExpr->GetType();
+  } else {
+    return std::nullopt;
+  }
+}
+
+const std::list<parser::OmpTraitProperty> &
+OmpStructureChecker::GetTraitPropertyList(
+    const parser::OmpTraitSelector &trait) {
+  static const std::list<parser::OmpTraitProperty> empty{};
+  auto &[_, maybeProps]{trait.t};
+  if (maybeProps) {
+    using PropertyList = std::list<parser::OmpTraitProperty>;
+    return std::get<PropertyList>(maybeProps->t);
+  } else {
+    return empty;
+  }
+}
+
+std::optional<llvm::omp::Clause> OmpStructureChecker::GetClauseFromProperty(
+    const parser::OmpTraitProperty &property) {
+  using MaybeClause = std::optional<llvm::omp::Clause>;
+
+  // The parser for OmpClause will only succeed if the clause was
+  // given with all required arguments.
+  // If this is a string or complex extensiom with a clause name,
----------------
tblah wrote:

```suggestion
  // If this is a string or complex extension with a clause name,
```

https://github.com/llvm/llvm-project/pull/123243