llvm/mlir/tools/mlir-tblgen/DirectiveCommonGen.cpp

//===========- DirectiveCommonGen.cpp - Directive common info generator -=====//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// OpenMPCommonGen generates utility information from the single OpenMP source
// of truth in llvm/lib/Frontend/OpenMP.
//
//===----------------------------------------------------------------------===//

#include "mlir/TableGen/GenInfo.h"

#include "llvm/ADT/Twine.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/DirectiveEmitter.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"

Clause;
ClauseVal;
raw_ostream;
Record;
RecordKeeper;

// LLVM has multiple places (Clang, Flang, MLIR) where information about
// the directives (OpenMP/OpenACC), and clauses are needed. It is good software
// engineering to keep the common information in a single place to avoid
// duplication, reduce engineering effort and prevent mistakes.
// Currently that common place is llvm/include/llvm/Frontend/OpenMP/OMP.td for
// OpenMP and llvm/include/llvm/Frontend/OpenACC/ACC.td for OpenACC.
// We plan to use this tablegen source to generate all the required
// declarations, functions etc.
//
// Some OpenMP/OpenACC clauses accept only a fixed set of values as inputs.
// These can be represented as a Enum Attributes (EnumAttrDef) in MLIR
// ODS. The emitDecls function below currently generates these enumerations. The
// name of the enumeration is specified in the enumClauseValue field of
// Clause record in OMP.td. This name can be used to specify the type of the
// OpenMP operation's operand. The allowedClauseValues field provides the list
// of ClauseValues which are part of the enumeration.
static bool emitDecls(const RecordKeeper &records, llvm::StringRef dialect,
                      raw_ostream &os) { … }

static llvm::cl::OptionCategory
    directiveGenCat("Options for gen-directive-decl");
static llvm::cl::opt<std::string>
    dialect("directives-dialect",
            llvm::cl::desc("Generate directives for this dialect"),
            llvm::cl::cat(directiveGenCat), llvm::cl::CommaSeparated);

// Registers the generator to mlir-tblgen.
static mlir::GenRegistration genDirectiveDecls(
    "gen-directive-decl",
    "Generate declarations for directives (OpenMP/OpenACC etc.)",
    [](const RecordKeeper &records, raw_ostream &os) { … });