llvm/llvm/include/llvm/IR/LegacyPassManagers.h

//===- LegacyPassManagers.h - Legacy Pass Infrastructure --------*- 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 declares the LLVM Pass Manager infrastructure.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_LEGACYPASSMANAGERS_H
#define LLVM_IR_LEGACYPASSMANAGERS_H

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Pass.h"
#include <vector>

//===----------------------------------------------------------------------===//
// Overview:
// The Pass Manager Infrastructure manages passes. It's responsibilities are:
//
//   o Manage optimization pass execution order
//   o Make required Analysis information available before pass P is run
//   o Release memory occupied by dead passes
//   o If Analysis information is dirtied by a pass then regenerate Analysis
//     information before it is consumed by another pass.
//
// Pass Manager Infrastructure uses multiple pass managers.  They are
// PassManager, FunctionPassManager, MPPassManager, FPPassManager, BBPassManager.
// This class hierarchy uses multiple inheritance but pass managers do not
// derive from another pass manager.
//
// PassManager and FunctionPassManager are two top-level pass manager that
// represents the external interface of this entire pass manager infrastucture.
//
// Important classes :
//
// [o] class PMTopLevelManager;
//
// Two top level managers, PassManager and FunctionPassManager, derive from
// PMTopLevelManager. PMTopLevelManager manages information used by top level
// managers such as last user info.
//
// [o] class PMDataManager;
//
// PMDataManager manages information, e.g. list of available analysis info,
// used by a pass manager to manage execution order of passes. It also provides
// a place to implement common pass manager APIs. All pass managers derive from
// PMDataManager.
//
// [o] class FunctionPassManager;
//
// This is a external interface used to manage FunctionPasses. This
// interface relies on FunctionPassManagerImpl to do all the tasks.
//
// [o] class FunctionPassManagerImpl : public ModulePass, PMDataManager,
//                                     public PMTopLevelManager;
//
// FunctionPassManagerImpl is a top level manager. It manages FPPassManagers
//
// [o] class FPPassManager : public ModulePass, public PMDataManager;
//
// FPPassManager manages FunctionPasses and BBPassManagers
//
// [o] class MPPassManager : public Pass, public PMDataManager;
//
// MPPassManager manages ModulePasses and FPPassManagers
//
// [o] class PassManager;
//
// This is a external interface used by various tools to manages passes. It
// relies on PassManagerImpl to do all the tasks.
//
// [o] class PassManagerImpl : public Pass, public PMDataManager,
//                             public PMTopLevelManager
//
// PassManagerImpl is a top level pass manager responsible for managing
// MPPassManagers.
//===----------------------------------------------------------------------===//

#include "llvm/Support/PrettyStackTrace.h"

namespace llvm {
template <typename T> class ArrayRef;
class Module;
class StringRef;
class Value;
class PMDataManager;

// enums for debugging strings
enum PassDebuggingString { … };

/// PassManagerPrettyStackEntry - This is used to print informative information
/// about what pass is running when/if a stack trace is generated.
class PassManagerPrettyStackEntry : public PrettyStackTraceEntry { … };

//===----------------------------------------------------------------------===//
// PMStack
//
/// PMStack - This class implements a stack data structure of PMDataManager
/// pointers.
///
/// Top level pass managers (see PassManager.cpp) maintain active Pass Managers
/// using PMStack. Each Pass implements assignPassManager() to connect itself
/// with appropriate manager. assignPassManager() walks PMStack to find
/// suitable manager.
class PMStack { … };

//===----------------------------------------------------------------------===//
// PMTopLevelManager
//
/// PMTopLevelManager manages LastUser info and collects common APIs used by
/// top level pass managers.
class PMTopLevelManager { … };

//===----------------------------------------------------------------------===//
// PMDataManager

/// PMDataManager provides the common place to manage the analysis data
/// used by pass managers.
class PMDataManager { … };

//===----------------------------------------------------------------------===//
// FPPassManager
//
/// FPPassManager manages BBPassManagers and FunctionPasses.
/// It batches all function passes and basic block pass managers together and
/// sequence them to process one function at a time before processing next
/// function.
class FPPassManager : public ModulePass, public PMDataManager { … };

}

#endif