//===- DialectHooks.h - MLIR DialectHooks mechanism -------------*- 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 file defines abstraction and registration mechanism for dialect hooks.

//

//===----------------------------------------------------------------------===//

#ifndef MLIR_IR_DIALECT_HOOKS_H

#define MLIR_IR_DIALECT_HOOKS_H

#include "mlir/IR/Dialect.h"

#include "llvm/Support/raw_ostream.h"

namespace mlir {

using DialectHooksSetter = std::function<void(MLIRContext *)>;

/// Dialect hooks allow external components to register their functions to

/// be called for specific tasks specialized per dialect, such as decoding

/// of opaque constants. To register concrete dialect hooks, one should

/// define a DialectHooks subclass and use it as a template

/// argument to DialectHooksRegistration. For example,

///     class MyHooks : public DialectHooks {...};

///     static DialectHooksRegistration<MyHooks, MyDialect> hooksReg;

/// The subclass should override DialectHook methods for supported hooks.

class DialectHooks {

public:

  // Returns hook to constant fold an operation.

  DialectConstantFoldHook getConstantFoldHook() { return nullptr; }

  // Returns hook to decode opaque constant tensor.

  DialectConstantDecodeHook getDecodeHook() { return nullptr; }

  // Returns hook to extract an element of an opaque constant tensor.

  DialectExtractElementHook getExtractElementHook() { return nullptr; }

private:

  /// Registers a function that will set hooks in the registered dialects.

  /// Registrations are deduplicated by dialect TypeID and only the first

  /// registration will be used.

  static void registerDialectHooksSetter(TypeID typeID,

                                         const DialectHooksSetter &function);

  template <typename ConcreteHooks>

  friend void registerDialectHooks(StringRef dialectName);

};

void registerDialectHooksSetter(TypeID typeID,

                                const DialectHooksSetter &function);

/// Utility to register dialect hooks. Client can register their dialect hooks

/// with the global registry by calling

/// registerDialectHooks<MyHooks>("dialect_namespace");

template <typename ConcreteHooks>

void registerDialectHooks(StringRef dialectName) {

  DialectHooks::registerDialectHooksSetter(

      TypeID::get<ConcreteHooks>(), [dialectName](MLIRContext *ctx) {

        Dialect *dialect = ctx->getRegisteredDialect(dialectName);

        if (!dialect) {

          llvm::errs() << "error: cannot register hooks for unknown dialect '"

                       << dialectName << "'\n";

          abort();

        }

        // Set hooks.

        ConcreteHooks hooks;

        if (auto h = hooks.getConstantFoldHook())

          dialect->constantFoldHook = h;

        if (auto h = hooks.getDecodeHook())

          dialect->decodeHook = h;

        if (auto h = hooks.getExtractElementHook())

          dialect->extractElementHook = h;

      });

}

/// DialectHooksRegistration provides a global initializer that registers

/// a dialect hooks setter routine.

/// Usage:

///

///   // At namespace scope.

///   static DialectHooksRegistration<MyHooks> Unused("dialect_namespace");

template <typename ConcreteHooks> struct DialectHooksRegistration {

  DialectHooksRegistration(StringRef dialectName) {

    registerDialectHooks<ConcreteHooks>(dialectName);

  }

};

} // namespace mlir

#endif