[flang][OpenMP][NFC] Reduce OMPMarkDeclareTarget boilerplate (#93797)

The pass constructor can be generated automatically by tablegen.

This pass does not need adapting to work with non-function top level
operations because it operates specifically on call operations inside of
an OpenMP declare target function.

Author: tblah

flang/include/flang/Optimizer/Transforms/Passes.h

@@ -52,6 +52,7 @@ namespace fir {
 #define GEN_PASS_DECL_LOOPVERSIONING
 #define GEN_PASS_DECL_ADDALIASTAGS
 #define GEN_PASS_DECL_OMPMAPINFOFINALIZATIONPASS
+#define GEN_PASS_DECL_OMPMARKDECLARETARGETPASS
 #include "flang/Optimizer/Transforms/Passes.h.inc"
 
 std::unique_ptr<mlir::Pass> createAffineDemotionPass();
@@ -72,8 +73,6 @@ std::unique_ptr<mlir::Pass>
 createAlgebraicSimplificationPass(const mlir::GreedyRewriteConfig &config);
 
 std::unique_ptr<mlir::Pass> createOMPFunctionFilteringPass();
-std::unique_ptr<mlir::OperationPass<mlir::ModuleOp>>
-createOMPMarkDeclareTargetPass();
 
 std::unique_ptr<mlir::Pass> createVScaleAttrPass();
 std::unique_ptr<mlir::Pass>

flang/include/flang/Optimizer/Transforms/Passes.td

@@ -337,7 +337,6 @@ def OMPMapInfoFinalizationPass
 def OMPMarkDeclareTargetPass
     : Pass<"omp-mark-declare-target", "mlir::ModuleOp"> {
   let summary = "Marks all functions called by an OpenMP declare target function as declare target";
-  let constructor = "::fir::createOMPMarkDeclareTargetPass()";
   let dependentDialects = ["mlir::omp::OpenMPDialect"];
 }
 

flang/lib/Optimizer/Transforms/OMPMarkDeclareTarget.cpp

@@ -88,10 +88,3 @@ class OMPMarkDeclareTargetPass
 };
 
 } // namespace
-
-namespace fir {
-std::unique_ptr<mlir::OperationPass<mlir::ModuleOp>>
-createOMPMarkDeclareTargetPass() {
-  return std::make_unique<OMPMarkDeclareTargetPass>();
-}
-} // namespace fir