[flang-commits] [flang] [flang][OpenMP] Implement flexible OpenMP clause representation (PR #81621)

[Sergio Afonso via flang-commits]

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@@ -142,6 +142,1122 @@ static void genNestedEvaluations(Fortran::lower::AbstractConverter &converter,
     converter.genEval(e);
 }
 
+//===----------------------------------------------------------------------===//
+// Clauses
+//===----------------------------------------------------------------------===//
+
+namespace detail {
+template <typename C> //
+llvm::omp::Clause getClauseIdForClass(C &&) {
+  using namespace Fortran;
+  using A = llvm::remove_cvref_t<C>; // A is referenced in OMP.inc
+  // The code included below contains a sequence of checks like the following
+  // for each OpenMP clause
+  //   if constexpr (std::is_same_v<A, parser::OmpClause::AcqRel>)
+  //     return llvm::omp::Clause::OMPC_acq_rel;
+  //   [...]
+#define GEN_FLANG_CLAUSE_PARSER_KIND_MAP
+#include "llvm/Frontend/OpenMP/OMP.inc"
+}
+} // namespace detail
+
+static llvm::omp::Clause getClauseId(const Fortran::parser::OmpClause &clause) {
+  return std::visit([](auto &&s) { return detail::getClauseIdForClass(s); },
+                    clause.u);
+}
+
+namespace omp {
+using namespace Fortran;
+using SomeType = evaluate::SomeType;
+using SomeExpr = semantics::SomeExpr;
+using MaybeExpr = semantics::MaybeExpr;
+
+template <typename T> //
+using List = std::vector<T>;
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skatrak wrote:

I was hoping we only needed to create clause structures and we were able to keep references to original symbols and expressions, but we're creating new expressions here then so you're right that it doesn't make sense to try to store them as references. I think for cases like this `llvm::SmallVector<T, 0>` is preferred over `std::vector`, so I'd still suggest making that small change.

https://github.com/llvm/llvm-project/pull/81621