[flang-commits] [flang] [Flang][MLIR][OpenMP] Create a deferred declare target marking process for Bridge.cpp (PR #78502)

[Sergio Afonso via flang-commits]

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@@ -4471,6 +4518,47 @@ bool Fortran::lower::isOpenMPDeviceDeclareTarget(
       ompDecl.u);
 }
 
+// In certain cases such as subroutine or function interfaces which declare
+// but do not define or directly call the subroutine or function in the same
+// module, their lowering is delayed until after the declare target construct
+// itself is processed, so there symbol is not within the table.
+//
+// This function will also return true if we encounter any device declare
+// target cases, to satisfy checking if we require the requires attributes
+// on the module.
+bool Fortran::lower::markOpenMPDeferredDeclareTargetFunctions(
+    mlir::Operation *mod,
+    llvm::SmallVectorImpl<OMPDeferredDeclTarInfo> &deferredDeclareTargets,
+    AbstractConverter &converter) {
+  bool deviceCodeFound = false;
+  if (auto modOp = llvm::dyn_cast<mlir::ModuleOp>(mod)) {
+    for (auto sym : deferredDeclareTargets) {
+      mlir::Operation *op =
+          modOp.lookupSymbol(converter.mangleName(std::get<2>(sym)));
+
+      // Due to interfaces being optionally emitted on usage in a module,
+      // not finding an operation at this point cannot be a hard error, we
+      // simply ignore it for now.
+      if (!op)
+        continue;
+
+      auto devType =
+          static_cast<mlir::omp::DeclareTargetDeviceType>(std::get<1>(sym));
+      if (!deviceCodeFound &&
+          devType != mlir::omp::DeclareTargetDeviceType::host) {
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skatrak wrote:

Nit: Braces not necessary here I think

https://github.com/llvm/llvm-project/pull/78502