include/llvm/PassSupport.h

//===- llvm/PassSupport.h - Pass Support code -------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines stuff that is used to define and "use" Passes.  This file
// is automatically #included by Pass.h, so:
//
//           NO .CPP FILES SHOULD INCLUDE THIS FILE DIRECTLY
//
// Instead, #include Pass.h.
//
// This file defines Pass registration code and classes used for it.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_PASS_SUPPORT_H
#define LLVM_PASS_SUPPORT_H

#include "llvm/Support/IncludeFile.h"
// No need to include Pass.h, we are being included by it!

namespace llvm {

class TargetMachine;

//===---------------------------------------------------------------------------
/// PassInfo class - An instance of this class exists for every pass known by
/// the system, and can be obtained from a live Pass by calling its
/// getPassInfo() method.  These objects are set up by the RegisterPass<>
/// template, defined below.
///
class PassInfo {
  const char           *PassName;      // Nice name for Pass
  const char           *PassArgument;  // Command Line argument to run this pass
  const std::type_info &TypeInfo;      // type_info object for this Pass class
  unsigned char PassType;              // Set of enums values below...
  std::vector<const PassInfo*> ItfImpl;// Interfaces implemented by this pass

  Pass *(*NormalCtor)();               // No argument ctor
  Pass *(*TargetCtor)(TargetMachine&);   // Ctor taking TargetMachine object...

public:
  /// PassType - Define symbolic constants that can be used to test to see if
  /// this pass should be listed by analyze or opt.  Passes can use none, one or
  /// many of these flags or'd together.  It is not legal to combine the
  /// AnalysisGroup flag with others.
  ///
  enum {
    Analysis = 1, Optimization = 2, AnalysisGroup = 4
  };

  /// PassInfo ctor - Do not call this directly, this should only be invoked
  /// through RegisterPass.
  PassInfo(const char *name, const char *arg, const std::type_info &ti,
           unsigned char pt, Pass *(*normal)() = 0,
           Pass *(*targetctor)(TargetMachine &) = 0)
    : PassName(name), PassArgument(arg), TypeInfo(ti), PassType(pt),
      NormalCtor(normal), TargetCtor(targetctor)  {
  }

  /// getPassName - Return the friendly name for the pass, never returns null
  ///
  const char *getPassName() const { return PassName; }
  void setPassName(const char *Name) { PassName = Name; }

  /// getPassArgument - Return the command line option that may be passed to
  /// 'opt' that will cause this pass to be run.  This will return null if there
  /// is no argument.
  ///
  const char *getPassArgument() const { return PassArgument; }

  /// getTypeInfo - Return the type_info object for the pass...
  ///
  const std::type_info &getTypeInfo() const { return TypeInfo; }

  /// getPassType - Return the PassType of a pass.  Note that this can be
  /// several different types or'd together.  This is _strictly_ for use by opt,
  /// analyze and llc for deciding which passes to use as command line options.
  ///
  unsigned getPassType() const { return PassType; }

  /// getNormalCtor - Return a pointer to a function, that when called, creates
  /// an instance of the pass and returns it.  This pointer may be null if there
  /// is no default constructor for the pass.
  ///
  Pass *(*getNormalCtor() const)() {
    return NormalCtor;
  }
  void setNormalCtor(Pass *(*Ctor)()) {
    NormalCtor = Ctor;
  }

  /// createPass() - Use this method to create an instance of this pass.
  Pass *createPass() const {
    assert((PassType != AnalysisGroup || NormalCtor) &&
           "No default implementation found for analysis group!");
    assert(NormalCtor &&
           "Cannot call createPass on PassInfo without default ctor!");
    return NormalCtor();
  }

  /// getTargetCtor - Return a pointer to a function that creates an instance of
  /// the pass and returns it.  This returns a constructor for a version of the
  /// pass that takes a TargetMachine object as a parameter.
  ///
  Pass *(*getTargetCtor() const)(TargetMachine &) {
    return TargetCtor;
  }

  /// addInterfaceImplemented - This method is called when this pass is
  /// registered as a member of an analysis group with the RegisterAnalysisGroup
  /// template.
  ///
  void addInterfaceImplemented(const PassInfo *ItfPI) {
    ItfImpl.push_back(ItfPI);
  }

  /// getInterfacesImplemented - Return a list of all of the analysis group
  /// interfaces implemented by this pass.
  ///
  const std::vector<const PassInfo*> &getInterfacesImplemented() const {
    return ItfImpl;
  }
};


//===---------------------------------------------------------------------------
/// RegisterPass<t> template - This template class is used to notify the system
/// that a Pass is available for use, and registers it into the internal
/// database maintained by the PassManager.  Unless this template is used, opt,
/// for example will not be able to see the pass and attempts to create the pass
/// will fail. This template is used in the follow manner (at global scope, in
/// your .cpp file):
///
/// static RegisterPass<YourPassClassName> tmp("passopt", "My Pass Name");
///
/// This statement will cause your pass to be created by calling the default
/// constructor exposed by the pass.  If you have a different constructor that
/// must be called, create a global constructor function (which takes the
/// arguments you need and returns a Pass*) and register your pass like this:
///
/// Pass *createMyPass(foo &opt) { return new MyPass(opt); }
/// static RegisterPass<PassClassName> tmp("passopt", "My Name", createMyPass);
///
struct RegisterPassBase {
  /// getPassInfo - Get the pass info for the registered class...
  ///
  const PassInfo *getPassInfo() const { return &PIObj; }

  RegisterPassBase(const char *Name, const char *Arg, const std::type_info &TI,
                   unsigned char PT, Pass *(*Normal)() = 0,
                   Pass *(*TargetCtor)(TargetMachine &) = 0)
    : PIObj(Name, Arg, TI, PT, Normal, TargetCtor) {
    registerPass();
  }
  RegisterPassBase(const std::type_info &TI, unsigned char PT)
    : PIObj("", "", TI, PT, 0, 0) {
    // This ctor may only be used for analysis groups: it does not auto-register
    // the pass.
    assert(PT == PassInfo::AnalysisGroup && "Not an AnalysisGroup!");
  }

  ~RegisterPassBase() {   // Intentionally non-virtual.
    // Analysis groups are registered/unregistered by their dtor.
    if (PIObj.getPassType() != PassInfo::AnalysisGroup)
      unregisterPass();
  }

protected:
  PassInfo PIObj;       // The PassInfo object for this pass
  void registerPass();
  void unregisterPass();

  /// setOnlyUsesCFG - Notice that this pass only depends on the CFG, so
  /// transformations that do not modify the CFG do not invalidate this pass.
  ///
  void setOnlyUsesCFG();
};

template<typename PassName>
Pass *callDefaultCtor() { return new PassName(); }

template<typename PassName>
struct RegisterPass : public RegisterPassBase {

  // Register Pass using default constructor...
  RegisterPass(const char *PassArg, const char *Name, unsigned char PassTy = 0)
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassTy,
                     callDefaultCtor<PassName>) {}

  // Register Pass using default constructor explicitly...
  RegisterPass(const char *PassArg, const char *Name, unsigned char PassTy,
               Pass *(*ctor)())
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassTy, ctor) {}

  // Register Pass using TargetMachine constructor...
  RegisterPass(const char *PassArg, const char *Name, unsigned char PassTy,
               Pass *(*targetctor)(TargetMachine &))
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassTy,
                     0, targetctor) {}

  // Generic constructor version that has an unknown ctor type...
  template<typename CtorType>
  RegisterPass(const char *PassArg, const char *Name, unsigned char PassTy,
               CtorType *Fn)
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassTy, 0) {}
};

/// RegisterOpt - Register something that is to show up in Opt, this is just a
/// shortcut for specifying RegisterPass...
///
template<typename PassName>
struct RegisterOpt : public RegisterPassBase {
  RegisterOpt(const char *PassArg, const char *Name, bool CFGOnly = false)
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassInfo::Optimization,
                     callDefaultCtor<PassName>) {
    if (CFGOnly) setOnlyUsesCFG();
  }

  /// Register Pass using default constructor explicitly...
  ///
  RegisterOpt(const char *PassArg, const char *Name, Pass *(*ctor)(),
              bool CFGOnly = false)
  : RegisterPassBase(Name, PassArg, typeid(PassName),
                     PassInfo::Optimization, ctor) {
    if (CFGOnly) setOnlyUsesCFG();
  }

  /// Register FunctionPass using default constructor explicitly...
  ///
  RegisterOpt(const char *PassArg, const char *Name, FunctionPass *(*ctor)(),
              bool CFGOnly = false)
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassInfo::Optimization,
                     static_cast<Pass*(*)()>(ctor)) {
    if (CFGOnly) setOnlyUsesCFG();
  }

  /// Register Pass using TargetMachine constructor...
  ///
  RegisterOpt(const char *PassArg, const char *Name,
               Pass *(*targetctor)(TargetMachine &), bool CFGOnly = false)
  : RegisterPassBase(Name, PassArg, typeid(PassName),
                     PassInfo::Optimization, 0, targetctor) {
    if (CFGOnly) setOnlyUsesCFG();
  }

  /// Register FunctionPass using TargetMachine constructor...
  ///
  RegisterOpt(const char *PassArg, const char *Name,
              FunctionPass *(*targetctor)(TargetMachine &),
              bool CFGOnly = false)
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassInfo::Optimization, 0,
                     static_cast<Pass*(*)(TargetMachine&)>(targetctor)) {
    if (CFGOnly) setOnlyUsesCFG();
  }
};

/// RegisterAnalysis - Register something that is to show up in Analysis, this
/// is just a shortcut for specifying RegisterPass...  Analyses take a special
/// argument that, when set to true, tells the system that the analysis ONLY
/// depends on the shape of the CFG, so if a transformation preserves the CFG
/// that the analysis is not invalidated.
///
template<typename PassName>
struct RegisterAnalysis : public RegisterPassBase {
  RegisterAnalysis(const char *PassArg, const char *Name,
                   bool CFGOnly = false)
  : RegisterPassBase(Name, PassArg, typeid(PassName), PassInfo::Analysis,
                     callDefaultCtor<PassName>) {
    if (CFGOnly) setOnlyUsesCFG();
  }
};


/// RegisterAnalysisGroup - Register a Pass as a member of an analysis _group_.
/// Analysis groups are used to define an interface (which need not derive from
/// Pass) that is required by passes to do their job.  Analysis Groups differ
/// from normal analyses because any available implementation of the group will
/// be used if it is available.
///
/// If no analysis implementing the interface is available, a default
/// implementation is created and added.  A pass registers itself as the default
/// implementation by specifying 'true' as the third template argument of this
/// class.
///
/// In addition to registering itself as an analysis group member, a pass must
/// register itself normally as well.  Passes may be members of multiple groups
/// and may still be "required" specifically by name.
///
/// The actual interface may also be registered as well (by not specifying the
/// second template argument).  The interface should be registered to associate
/// a nice name with the interface.
///
class RegisterAGBase : public RegisterPassBase {
  PassInfo *InterfaceInfo;
  const PassInfo *ImplementationInfo;
  bool isDefaultImplementation;
protected:
  RegisterAGBase(const std::type_info &Interface,
                 const std::type_info *Pass = 0,
                 bool isDefault = false);
  void setGroupName(const char *Name);
public:
  ~RegisterAGBase();
};


template<typename Interface, typename DefaultImplementationPass = void,
         bool Default = false>
struct RegisterAnalysisGroup : public RegisterAGBase {
  RegisterAnalysisGroup() : RegisterAGBase(typeid(Interface),
                                           &typeid(DefaultImplementationPass),
                                           Default) {
  }
};

/// Define a specialization of RegisterAnalysisGroup that is used to set the
/// name for the analysis group.
///
template<typename Interface>
struct RegisterAnalysisGroup<Interface, void, false> : public RegisterAGBase {
  RegisterAnalysisGroup(const char *Name)
    : RegisterAGBase(typeid(Interface)) {
    setGroupName(Name);
  }
};


//===---------------------------------------------------------------------------
/// PassRegistrationListener class - This class is meant to be derived from by
/// clients that are interested in which passes get registered and unregistered
/// at runtime (which can be because of the RegisterPass constructors being run
/// as the program starts up, or may be because a shared object just got
/// loaded).  Deriving from the PassRegistationListener class automatically
/// registers your object to receive callbacks indicating when passes are loaded
/// and removed.
///
struct PassRegistrationListener {

  /// PassRegistrationListener ctor - Add the current object to the list of
  /// PassRegistrationListeners...
  PassRegistrationListener();

  /// dtor - Remove object from list of listeners...
  ///
  virtual ~PassRegistrationListener();

  /// Callback functions - These functions are invoked whenever a pass is loaded
  /// or removed from the current executable.
  ///
  virtual void passRegistered(const PassInfo *P) {}
  virtual void passUnregistered(const PassInfo *P) {}

  /// enumeratePasses - Iterate over the registered passes, calling the
  /// passEnumerate callback on each PassInfo object.
  ///
  void enumeratePasses();

  /// passEnumerate - Callback function invoked when someone calls
  /// enumeratePasses on this PassRegistrationListener object.
  ///
  virtual void passEnumerate(const PassInfo *P) {}
};

} // End llvm namespace

#endif