[flang-commits] [flang] [flang][OpenMP] Implicit declarations of procedures in DECLARE_TARGET (PR #201935)

[via flang-commits]

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@@ -9756,6 +9742,28 @@ void ResolveNamesVisitor::HandleProcedureName(
     Symbol::Flag flag, const parser::Name &name) {
   CHECK(flag == Symbol::Flag::Function || flag == Symbol::Flag::Subroutine);
   auto *symbol{FindSymbol(NonDerivedTypeScope(), name)};
+  // A symbol listed on OpenMP declare_target directive may be a variable
+  // or a procedure. If the directive is the first occurrence of the name,
+  // it will create an implicit declaration of an object (since the name
+  // is not used in a call at that location). If the name turns out to be
+  // that of a procedure, this is going to create a problem.
+  // If a symbol was created because of its appearance in a declare_target,
+  // a use in a call should override it with the procedure symbol.
+  Scope *ompDTScope{nullptr};
+  // A name implicitly declared by a DECLARE_TARGET may have been followed
+  // by an explcit declaration. Make sure the symbol is still implicit
+  // before doing anything.
+  if (WasDeclaredByOmpDeclareTarget(symbol) &&
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MattPD wrote:

This recovery only runs on a call or function reference. If a declare-target name is never called in the scope (just listed, or passed as an actual argument), the symbol stays an implicit object and trips the declare-target variable rule. The removed `FindAndMarkDeclareTargetSymbol` (added by llvm/llvm-project#122546) resolved those non-call uses by searching the enclosing scopes. Is dropping that intentional?

Current trunk (before this PR) accepts this case: https://flang.godbolt.org/z/x7G7rEsnY

https://github.com/llvm/llvm-project/pull/201935