llvm/llvm/include/llvm/Pass.h

//===- llvm/Pass.h - Base class for Passes ----------------------*- 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 a base class that indicates that a specified class is a
// transformation pass implementation.
//
// Passes are designed this way so that it is possible to run passes in a cache
// and organizationally optimal order without having to specify it at the front
// end.  This allows arbitrary passes to be strung together and have them
// executed as efficiently as possible.
//
// Passes should extend one of the classes below, depending on the guarantees
// that it can make about what will be modified as it is run.  For example, most
// global optimizations should derive from FunctionPass, because they do not add
// or delete functions, they operate on the internals of the function.
//
// Note that this file #includes PassSupport.h and PassAnalysisSupport.h (at the
// bottom), so the APIs exposed by these files are also automatically available
// to all users of this file.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_PASS_H
#define LLVM_PASS_H

#ifdef EXPENSIVE_CHECKS
#include <cstdint>
#endif
#include <string>

namespace llvm {

class AnalysisResolver;
class AnalysisUsage;
class Function;
class ImmutablePass;
class Module;
class PassInfo;
class PMDataManager;
class PMStack;
class raw_ostream;
class StringRef;

// AnalysisID - Use the PassInfo to identify a pass...
AnalysisID;

/// Different types of internal pass managers. External pass managers
/// (PassManager and FunctionPassManager) are not represented here.
/// Ordering of pass manager types is important here.
enum PassManagerType { … };

// Different types of passes.
enum PassKind { … };

/// This enumerates the LLVM full LTO or ThinLTO optimization phases.
enum class ThinOrFullLTOPhase { … };

//===----------------------------------------------------------------------===//
/// Pass interface - Implemented by all 'passes'.  Subclass this if you are an
/// interprocedural optimization or you do not fit into any of the more
/// constrained passes described below.
///
class Pass { … };

//===----------------------------------------------------------------------===//
/// ModulePass class - This class is used to implement unstructured
/// interprocedural optimizations and analyses.  ModulePasses may do anything
/// they want to the program.
///
class ModulePass : public Pass { … };

//===----------------------------------------------------------------------===//
/// ImmutablePass class - This class is used to provide information that does
/// not need to be run.  This is useful for things like target information.
///
class ImmutablePass : public ModulePass { … };

//===----------------------------------------------------------------------===//
/// FunctionPass class - This class is used to implement most global
/// optimizations.  Optimizations should subclass this class if they meet the
/// following constraints:
///
///  1. Optimizations are organized globally, i.e., a function at a time
///  2. Optimizing a function does not cause the addition or removal of any
///     functions in the module
///
class FunctionPass : public Pass { … };

/// If the user specifies the -time-passes argument on an LLVM tool command line
/// then the value of this boolean will be true, otherwise false.
/// This is the storage for the -time-passes option.
extern bool TimePassesIsEnabled;
/// If TimePassesPerRun is true, there would be one line of report for
/// each pass invocation.
/// If TimePassesPerRun is false, there would be only one line of
/// report for each pass (even there are more than one pass objects).
/// (For new pass manager only)
extern bool TimePassesPerRun;

} // end namespace llvm

// Include support files that contain important APIs commonly used by Passes,
// but that we want to separate out to make it easier to read the header files.
#include "llvm/PassAnalysisSupport.h"
#include "llvm/PassSupport.h"

#endif // LLVM_PASS_H