llvm/mlir/include/mlir/Analysis/DataFlow/DenseAnalysis.h

//===- DenseAnalysis.h - Dense data-flow analysis -------------------------===//
//
// 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 implements dense data-flow analysis using the data-flow analysis
// framework. The analysis is forward and conditional and uses the results of
// dead code analysis to prune dead code during the analysis.
//
//===----------------------------------------------------------------------===//

#ifndef MLIR_ANALYSIS_DENSEDATAFLOWANALYSIS_H
#define MLIR_ANALYSIS_DENSEDATAFLOWANALYSIS_H

#include "mlir/Analysis/DataFlowFramework.h"
#include "mlir/IR/SymbolTable.h"
#include "mlir/Interfaces/CallInterfaces.h"
#include "mlir/Interfaces/ControlFlowInterfaces.h"

namespace mlir {
namespace dataflow {

//===----------------------------------------------------------------------===//
// CallControlFlowAction
//===----------------------------------------------------------------------===//

/// Indicates whether the control enters, exits, or skips over the callee (in
/// the case of external functions).
enum class CallControlFlowAction { … };

//===----------------------------------------------------------------------===//
// AbstractDenseLattice
//===----------------------------------------------------------------------===//

/// This class represents a dense lattice. A dense lattice is attached to
/// operations to represent the program state after their execution or to blocks
/// to represent the program state at the beginning of the block. A dense
/// lattice is propagated through the IR by dense data-flow analysis.
class AbstractDenseLattice : public AnalysisState { … };

//===----------------------------------------------------------------------===//
// AbstractDenseForwardDataFlowAnalysis
//===----------------------------------------------------------------------===//

/// Base class for dense forward data-flow analyses. Dense data-flow analysis
/// attaches a lattice between the execution of operations and implements a
/// transfer function from the lattice before each operation to the lattice
/// after. The lattice contains information about the state of the program at
/// that point.
///
/// In this implementation, a lattice attached to an operation represents the
/// state of the program after its execution, and a lattice attached to block
/// represents the state of the program right before it starts executing its
/// body.
class AbstractDenseForwardDataFlowAnalysis : public DataFlowAnalysis { … };

//===----------------------------------------------------------------------===//
// DenseForwardDataFlowAnalysis
//===----------------------------------------------------------------------===//

/// A dense forward data-flow analysis for propagating lattices before and
/// after the execution of every operation across the IR by implementing
/// transfer functions for operations.
///
/// `LatticeT` is expected to be a subclass of `AbstractDenseLattice`.
template <typename LatticeT>
class DenseForwardDataFlowAnalysis
    : public AbstractDenseForwardDataFlowAnalysis { … };

//===----------------------------------------------------------------------===//
// AbstractDenseBackwardDataFlowAnalysis
//===----------------------------------------------------------------------===//

/// Base class for dense backward dataflow analyses. Such analyses attach a
/// lattice between the execution of operations and implement a transfer
/// function from the lattice after the operation ot the lattice before it, thus
/// propagating backward.
///
/// In this implementation, a lattice attached to an operation represents the
/// state of the program before its execution, and a lattice attached to a block
/// represents the state of the program before the end of the block, i.e., after
/// its terminator.
class AbstractDenseBackwardDataFlowAnalysis : public DataFlowAnalysis { … };

//===----------------------------------------------------------------------===//
// DenseBackwardDataFlowAnalysis
//===----------------------------------------------------------------------===//

/// A dense backward dataflow analysis propagating lattices after and before the
/// execution of every operation across the IR by implementing transfer
/// functions for opreations.
///
/// `LatticeT` is expected to be a subclass of `AbstractDenseLattice`.
template <typename LatticeT>
class DenseBackwardDataFlowAnalysis
    : public AbstractDenseBackwardDataFlowAnalysis { … };

} // end namespace dataflow
} // end namespace mlir

#endif // MLIR_ANALYSIS_DENSEDATAFLOWANALYSIS_H