[flang][NFC] Move OpenMP related passes into a separate directory (#104732)

Reapplied with fixed library dependencies for shared lib build

Author: ivanradanov

flang/docs/OpenMP-declare-target.md

@@ -149,15 +149,15 @@ flang/lib/Lower/OpenMP.cpp function `genDeclareTargetIntGlobal`.
 
 There are currently two passes within Flang that are related to the processing 
 of `declare target`:
-* `OMPMarkDeclareTarget` - This pass is in charge of marking functions captured
+* `MarkDeclareTarget` - This pass is in charge of marking functions captured
 (called from) in `target` regions or other `declare target` marked functions as
 `declare target`. It does so recursively, i.e. nested calls will also be 
 implicitly marked. It currently will try to mark things as conservatively as 
 possible, e.g. if captured in a `target` region it will apply `nohost`, unless
 it encounters a `host` `declare target` in which case it will apply the `any` 
 device type. Functions are handled similarly, except we utilise the parent's 
 device type where possible.
-* `OMPFunctionFiltering` - This is executed after the `OMPMarkDeclareTarget`
+* `FunctionFiltering` - This is executed after the `MarkDeclareTarget`
 pass, and its job is to conservatively remove host functions from
 the module where possible when compiling for the device. This helps make 
 sure that most incompatible code for the host is not lowered for the 

flang/docs/OpenMP-descriptor-management.md

@@ -44,7 +44,7 @@ Currently, Flang will lower these descriptor types in the OpenMP lowering (lower
 to all other map types, generating an omp.MapInfoOp containing relevant information required for lowering
 the OpenMP dialect to LLVM-IR during the final stages of the MLIR lowering. However, after 
 the lowering to FIR/HLFIR has been performed an OpenMP dialect specific pass for Fortran, 
-`OMPMapInfoFinalizationPass` (Optimizer/OMPMapInfoFinalization.cpp) will expand the 
+`MapInfoFinalizationPass` (Optimizer/OpenMP/MapInfoFinalization.cpp) will expand the 
 `omp.MapInfoOp`'s containing descriptors (which currently will be a `BoxType` or `BoxAddrOp`) into multiple 
 mappings, with one extra per pointer member in the descriptor that is supported on top of the original
 descriptor map operation. These pointers members are linked to the parent descriptor by adding them to 
@@ -53,7 +53,7 @@ owning operation's (`omp.TargetOp`, `omp.TargetDataOp` etc.) map operand list an
 operation is `IsolatedFromAbove`, it also inserts them as `BlockArgs` to canonicalize the mappings and
 simplify lowering.
 
-An example transformation by the `OMPMapInfoFinalizationPass`:
+An example transformation by the `MapInfoFinalizationPass`:
 
 ```
 

flang/include/flang/Optimizer/CMakeLists.txt

@@ -2,3 +2,4 @@ add_subdirectory(CodeGen)
 add_subdirectory(Dialect)
 add_subdirectory(HLFIR)
 add_subdirectory(Transforms)
+add_subdirectory(OpenMP)

flang/include/flang/Optimizer/OpenMP/CMakeLists.txt

@@ -0,0 +1,4 @@
+set(LLVM_TARGET_DEFINITIONS Passes.td)
+mlir_tablegen(Passes.h.inc -gen-pass-decls -name FlangOpenMP)
+
+add_public_tablegen_target(FlangOpenMPPassesIncGen)

flang/include/flang/Optimizer/OpenMP/Passes.h

@@ -0,0 +1,30 @@
+//===- Passes.h - OpenMP pass entry points ----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This header declares the flang OpenMP passes.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_OPTIMIZER_OPENMP_PASSES_H
+#define FORTRAN_OPTIMIZER_OPENMP_PASSES_H
+
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/IR/BuiltinOps.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Pass/PassRegistry.h"
+
+#include <memory>
+
+namespace flangomp {
+#define GEN_PASS_DECL
+#define GEN_PASS_REGISTRATION
+#include "flang/Optimizer/OpenMP/Passes.h.inc"
+
+} // namespace flangomp
+
+#endif // FORTRAN_OPTIMIZER_OPENMP_PASSES_H

flang/include/flang/Optimizer/OpenMP/Passes.td

@@ -0,0 +1,40 @@
+//===-- Passes.td - flang OpenMP pass definition -----------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_OPTIMIZER_OPENMP_PASSES
+#define FORTRAN_OPTIMIZER_OPENMP_PASSES
+
+include "mlir/Pass/PassBase.td"
+
+def MapInfoFinalizationPass
+    : Pass<"omp-map-info-finalization"> {
+  let summary = "expands OpenMP MapInfo operations containing descriptors";
+  let description = [{
+    Expands MapInfo operations containing descriptor types into multiple
+    MapInfo's for each pointer element in the descriptor that requires
+    explicit individual mapping by the OpenMP runtime.
+  }];
+  let dependentDialects = ["mlir::omp::OpenMPDialect"];
+}
+
+def MarkDeclareTargetPass
+    : Pass<"omp-mark-declare-target", "mlir::ModuleOp"> {
+  let summary = "Marks all functions called by an OpenMP declare target function as declare target";
+  let dependentDialects = ["mlir::omp::OpenMPDialect"];
+}
+
+def FunctionFiltering : Pass<"omp-function-filtering"> {
+  let summary = "Filters out functions intended for the host when compiling "
+                "for the target device.";
+  let dependentDialects = [
+    "mlir::func::FuncDialect",
+    "fir::FIROpsDialect"
+  ];
+}
+
+#endif //FORTRAN_OPTIMIZER_OPENMP_PASSES

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

@@ -358,32 +358,6 @@ def LoopVersioning : Pass<"loop-versioning", "mlir::func::FuncOp"> {
   let dependentDialects = [ "fir::FIROpsDialect" ];
 }
 
-def OMPMapInfoFinalizationPass
-    : Pass<"omp-map-info-finalization"> {
-  let summary = "expands OpenMP MapInfo operations containing descriptors";
-  let description = [{
-    Expands MapInfo operations containing descriptor types into multiple 
-    MapInfo's for each pointer element in the descriptor that requires 
-    explicit individual mapping by the OpenMP runtime.
-  }];
-  let dependentDialects = ["mlir::omp::OpenMPDialect"];
-}
-
-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 dependentDialects = ["mlir::omp::OpenMPDialect"];
-}
-
-def OMPFunctionFiltering : Pass<"omp-function-filtering"> {
-  let summary = "Filters out functions intended for the host when compiling "
-                "for the target device.";
-  let dependentDialects = [
-    "mlir::func::FuncDialect",
-    "fir::FIROpsDialect"
-  ];
-}
-
 def VScaleAttr : Pass<"vscale-attr", "mlir::func::FuncOp"> {
   let summary = "Add vscale_range attribute to functions";
   let description = [{

flang/include/flang/Tools/CLOptions.inc

@@ -17,6 +17,7 @@
 #include "mlir/Transforms/Passes.h"
 #include "flang/Optimizer/CodeGen/CodeGen.h"
 #include "flang/Optimizer/HLFIR/Passes.h"
+#include "flang/Optimizer/OpenMP/Passes.h"
 #include "flang/Optimizer/Transforms/Passes.h"
 #include "llvm/Passes/OptimizationLevel.h"
 #include "llvm/Support/CommandLine.h"
@@ -367,10 +368,10 @@ inline void createHLFIRToFIRPassPipeline(
 inline void createOpenMPFIRPassPipeline(
     mlir::PassManager &pm, bool isTargetDevice) {
   addNestedPassToAllTopLevelOperations(
-      pm, fir::createOMPMapInfoFinalizationPass);
-  pm.addPass(fir::createOMPMarkDeclareTargetPass());
+      pm, flangomp::createMapInfoFinalizationPass);
+  pm.addPass(flangomp::createMarkDeclareTargetPass());
   if (isTargetDevice)
-    pm.addPass(fir::createOMPFunctionFiltering());
+    pm.addPass(flangomp::createFunctionFiltering());
 }
 
 #if !defined(FLANG_EXCLUDE_CODEGEN)

flang/lib/Frontend/CMakeLists.txt

@@ -38,6 +38,7 @@ add_flang_library(flangFrontend
   FIRTransforms
   HLFIRDialect
   HLFIRTransforms
+  FlangOpenMPTransforms
   MLIRTransforms
   MLIRBuiltinToLLVMIRTranslation
   MLIRLLVMToLLVMIRTranslation

flang/lib/Optimizer/CMakeLists.txt

@@ -5,3 +5,4 @@ add_subdirectory(HLFIR)
 add_subdirectory(Support)
 add_subdirectory(Transforms)
 add_subdirectory(Analysis)
+add_subdirectory(OpenMP)