llvm/llvm/tools/llvm-reduce/deltas/Delta.h

//===- Delta.h - Delta Debugging Algorithm Implementation -------*- 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 contains the implementation for the Delta Debugging Algorithm:
// it splits a given set of Targets (i.e. Functions, Instructions, BBs, etc.)
// into chunks and tries to reduce the number chunks that are interesting.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TOOLS_LLVM_REDUCE_DELTAS_DELTA_H
#define LLVM_TOOLS_LLVM_REDUCE_DELTAS_DELTA_H

#include "ReducerWorkItem.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Support/raw_ostream.h"
#include <functional>
#include <utility>

namespace llvm {

class TestRunner;

struct Chunk { … };

template<>
struct DenseMapInfo<Chunk> { … };


/// Provides opaque interface for querying into ChunksToKeep without having to
/// actually understand what is going on.
class Oracle { … };

ReductionFunc;

/// This function implements the Delta Debugging algorithm, it receives a
/// number of Targets (e.g. Functions, Instructions, Basic Blocks, etc.) and
/// splits them in half; these chunks of targets are then tested while ignoring
/// one chunk, if a chunk is proven to be uninteresting (i.e. fails the test)
/// it is removed from consideration. The algorithm will attempt to split the
/// Chunks in half and start the process again until it can't split chunks
/// anymore.
///
/// This function is intended to be called by each specialized delta pass (e.g.
/// RemoveFunctions) and receives three key parameters:
/// * Test: The main TestRunner instance which is used to run the provided
/// interesting-ness test, as well as to store and access the reduced Program.
/// * ExtractChunksFromModule: A function used to tailor the main program so it
/// only contains Targets that are inside Chunks of the given iteration.
/// Note: This function is implemented by each specialized Delta pass
///
/// Other implementations of the Delta Debugging algorithm can also be found in
/// the CReduce, Delta, and Lithium projects.
void runDeltaPass(TestRunner &Test, ReductionFunc ExtractChunksFromModule,
                  StringRef Message);
} // namespace llvm

#endif