[MLIR][OpenMP] Add OMP Declare Mapper MLIR Op definition

This patch adds the OMP.DeclareMapperOp to MLIR.

Author: TIFitis

mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td

@@ -1749,6 +1749,34 @@ def ScanOp : OpenMP_Op<"scan", [
   let hasVerifier = 1;
 }
 
+//===----------------------------------------------------------------------===//
+// 2.19.7.3 Declare Mapper Directive
+//===----------------------------------------------------------------------===//
+def DeclareMapperOp : OpenMP_Op<"declare_mapper", traits = [
+  Symbol], clauses = [
+    OpenMP_MapClause
+  ]> {
+  let summary = "declare mapper directive";
+  let description = [{
+    The declare mapper directive declares a user-defined mapper for a given
+    type, and may define a mapper-identifier that can be used in a map clause.
+  }] # clausesDescription;
+
+  let arguments = !con((ins SymbolNameAttr:$sym_name,
+                            OpenMP_PointerLikeType:$var_ptr,
+                            TypeAttr:$var_type), clausesArgs);
+
+  let builders = [
+    OpBuilder<(ins CArg<"const DeclareMapperOperands &">:$clauses)>
+  ];
+
+  // Override clause-based assemblyFormat.
+  let assemblyFormat = "$sym_name `:` $var_ptr `:` type($var_ptr) `:` $var_type" # " oilist(" #
+    clausesOptAssemblyFormat # ")  attr-dict";
+
+  let hasVerifier = 1;
+}
+
 //===----------------------------------------------------------------------===//
 // 2.19.5.7 declare reduction Directive
 //===----------------------------------------------------------------------===//

mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp

@@ -2432,6 +2432,14 @@ LogicalResult DistributeOp::verifyRegions() {
   return success();
 }
 
+//===----------------------------------------------------------------------===//
+// DeclareMapperOp
+//===----------------------------------------------------------------------===//
+
+LogicalResult DeclareMapperOp::verify() {
+  return verifyMapClause(*this, getMapVars());
+}
+
 //===----------------------------------------------------------------------===//
 // DeclareReductionOp
 //===----------------------------------------------------------------------===//

mlir/test/Dialect/OpenMP/ops.mlir

@@ -879,6 +879,14 @@ cleanup {
   omp.yield
 }
 
+// CHECK: %[[DECL_VAR:.*]] = llvm.alloca %{{.*}}
+// CHECK: %[[DECL_MAP_INFO:.*]] = omp.map.info var_ptr(%[[DECL_VAR]] : !llvm.ptr, !llvm.struct<"my_type", (i32)>) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = ""}
+// CHECK: omp.declare_mapper @my_mapper : %[[DECL_VAR]] : !llvm.ptr : !llvm.struct<"my_type", (i32)> map_entries(%[[DECL_MAP_INFO]] : !llvm.ptr)
+%decl_c1 = arith.constant 1 : i64
+%decl_var = llvm.alloca %decl_c1 x !llvm.struct<"my_type", (i32)> : (i64) -> !llvm.ptr
+%decl_map_info = omp.map.info var_ptr(%decl_var : !llvm.ptr, !llvm.struct<"my_type", (i32)>) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = ""}
+omp.declare_mapper @my_mapper : %decl_var : !llvm.ptr : !llvm.struct<"my_type", (i32)> map_entries(%decl_map_info : !llvm.ptr)
+
 // CHECK-LABEL: func @wsloop_reduction
 func.func @wsloop_reduction(%lb : index, %ub : index, %step : index) {
   %c1 = arith.constant 1 : i32