[flang][OpenACC] Enable OpenACC codegen in Flang

[unterumarmung]

Summary

This patch adds OpenACC code generation capabilities to Flang.
It is done similarly to OpenMP codegen since they are designed in a
resembling manner.

Depends on D133226

[unterumarmung]

Should I add tests for this change? If so, what should they look like?
I couldn't find tests for similar functionality with OpenMP

[clementval]

I see that you posted couple of patch to OpenACC today. Are you planing to work on it further?

[unterumarmung]

In D133228#3767683, @clementval wrote:

I see that you posted couple of patch to OpenACC today. Are you planing to work on it further?

I am. But I cannot guarantee anything specific about it.

[clementval]

In D133228#3767694, @unterumarmung wrote:

In D133228#3767683, @clementval wrote:

I see that you posted couple of patch to OpenACC today. Are you planing to work on it further?

I am. But I cannot guarantee anything specific about it.

If you do it would be good to coordinate with other people working on it.

[clementval]

As discussed on discourse, we need a pass to convert FIR types before this can be enabled.

flang/lib/Optimizer/CodeGen/CMakeLists.txt

add_flang_library(FIRCodeGen
   LINK_LIBS
   FIRBuilder
   FIRDialect
   FIRSupport
   MLIRMathToFuncs
   MLIRMathToLLVM
   MLIRMathToLibm
   MLIROpenMPToLLVM
+  MLIROpenACCToLLVM
   MLIRLLVMToLLVMIRTranslation
   MLIRTargetLLVMIRExport
 
   LINK_COMPONENTS
   AsmParser
   AsmPrinter
   Remarks
 )

flang/lib/Optimizer/CodeGen/CodeGen.cpp

 #include "flang/Semantics/runtime-type-info.h"
 #include "mlir/Conversion/ArithmeticToLLVM/ArithmeticToLLVM.h"
 #include "mlir/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.h"
 #include "mlir/Conversion/FuncToLLVM/ConvertFuncToLLVM.h"
 #include "mlir/Conversion/LLVMCommon/Pattern.h"
 #include "mlir/Conversion/MathToFuncs/MathToFuncs.h"
 #include "mlir/Conversion/MathToLLVM/MathToLLVM.h"
 #include "mlir/Conversion/MathToLibm/MathToLibm.h"
+#include "mlir/Conversion/OpenACCToLLVM/ConvertOpenACCToLLVM.h"
 #include "mlir/Conversion/OpenMPToLLVM/ConvertOpenMPToLLVM.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/Dialect/OpenACC/OpenACC.h"
 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
 #include "mlir/IR/BuiltinTypes.h"
 #include "mlir/IR/Matchers.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Pass/PassManager.h"
 #include "mlir/Target/LLVMIR/ModuleTranslation.h"
 #include "llvm/ADT/ArrayRef.h"
 
pattern.insert<
         ShapeOpConversion, ShapeShiftOpConversion, ShiftOpConversion,
         SliceOpConversion, StoreOpConversion, StringLitOpConversion,
         SubcOpConversion, UnboxCharOpConversion, UnboxProcOpConversion,
         UndefOpConversion, UnreachableOpConversion, XArrayCoorOpConversion,
         XEmboxOpConversion, XReboxOpConversion, ZeroOpConversion>(typeConverter,
                                                                   options);
     mlir::populateFuncToLLVMConversionPatterns(typeConverter, pattern);
     mlir::populateOpenMPToLLVMConversionPatterns(typeConverter, pattern);
+    mlir::populateOpenACCToLLVMConversionPatterns(typeConverter, pattern);
     mlir::arith::populateArithmeticToLLVMConversionPatterns(typeConverter,
                                                             pattern);
     mlir::cf::populateControlFlowToLLVMConversionPatterns(typeConverter,
                                                           pattern);
     // Convert math-like dialect operations, which can be produced
     // when late math lowering mode is used, into llvm dialect.
     mlir::populateMathToLLVMConversionPatterns(typeConverter, pattern);
     mlir::populateMathToLibmConversionPatterns(pattern, /*benefit=*/0);
     mlir::ConversionTarget target{*context};
     target.addLegalDialect<mlir::LLVM::LLVMDialect>();
     // The OpenMP dialect is legal for Operations without regions, for those
     // which contains regions it is legal if the region contains only the
     // LLVM dialect. Add OpenMP dialect as a legal dialect for conversion and
     // legalize conversion of OpenMP operations without regions.
     mlir::configureOpenMPToLLVMConversionLegality(target, typeConverter);
     target.addLegalDialect<mlir::omp::OpenMPDialect>();
 
+    mlir::configureOpenACCToLLVMConversionLegality(target, typeConverter);
+    target.addLegalDialect<mlir::acc::OpenACCDialect>();
+
     // required NOPs for applying a full conversion
     target.addLegalOp<mlir::ModuleOp>();
 
     // apply the patterns
     if (mlir::failed(mlir::applyFullConversion(getModule(), target,
                                                std::move(pattern)))) {
       signalPassFailure();
     }

flang/lib/Optimizer/Support/CMakeLists.txt

 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
 
 add_flang_library(FIRSupport
   FIRContext.cpp
   InitFIR.cpp
   InternalNames.cpp
   KindMapping.cpp
 
   DEPENDS
   FIROpsIncGen
   MLIRIR
   ${dialect_libs}
 
   LINK_LIBS
   ${dialect_libs}
   MLIROpenMPToLLVMIRTranslation
+  MLIROpenACCToLLVMIRTranslation
   MLIRLLVMToLLVMIRTranslation
   MLIRTargetLLVMIRExport
 )

flang/lib/Optimizer/Support/InitFIR.cpp

 //===-- Optimizer/Support/InitFIR.cpp -------------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "flang/Optimizer/Support/InitFIR.h"
 #include "mlir/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.h"
+#include "mlir/Target/LLVMIR/Dialect/OpenACC/OpenACCToLLVMIRTranslation.h"
 #include "mlir/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.h"
 
 void fir::support::registerLLVMTranslation(mlir::MLIRContext &context) {
   mlir::DialectRegistry registry;
   // Register OpenMP dialect interface here as well.
   mlir::registerOpenMPDialectTranslation(registry);
+  // Register OpenACC dialect interface here as well.
+  mlir::registerOpenACCDialectTranslation(registry);
   // Register LLVM-IR dialect interface.
   registerLLVMDialectTranslation(registry);
   context.appendDialectRegistry(registry);
 }