LLVM API Documentation

PassSupport.h

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//===- llvm/PassSupport.h - Pass Support code -------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file 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

// 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 {
public:
  typedef Pass* (*NormalCtor_t)();

private:
  const char      *const PassName;     // Nice name for Pass
  const char      *const PassArgument; // Command Line argument to run this pass
  const intptr_t  PassID;      
  const bool IsCFGOnlyPass;            // Pass only looks at the CFG.
  const bool IsAnalysis;               // True if an analysis pass.
  const bool IsAnalysisGroup;          // True if an analysis group.
  std::vector<const PassInfo*> ItfImpl;// Interfaces implemented by this pass

  NormalCtor_t NormalCtor;

public:
  /// PassInfo ctor - Do not call this directly, this should only be invoked
  /// through RegisterPass.
  PassInfo(const char *name, const char *arg, intptr_t pi,
           NormalCtor_t normal = 0,
           bool isCFGOnly = false, bool is_analysis = false)
    : PassName(name), PassArgument(arg), PassID(pi), 
      IsCFGOnlyPass(isCFGOnly), 
      IsAnalysis(is_analysis), IsAnalysisGroup(false), NormalCtor(normal) {
    registerPass();
  }
  /// PassInfo ctor - Do not call this directly, this should only be invoked
  /// through RegisterPass. This version is for use by analysis groups; it
  /// does not auto-register the pass.
  PassInfo(const char *name, intptr_t pi)
    : PassName(name), PassArgument(""), PassID(pi), 
      IsCFGOnlyPass(false), 
      IsAnalysis(false), IsAnalysisGroup(true), NormalCtor(0) {
  }

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

  /// 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 id object for the pass...
  /// TODO : Rename
  intptr_t getTypeInfo() const { return PassID; }

  /// isAnalysisGroup - Return true if this is an analysis group, not a normal
  /// pass.
  ///
  bool isAnalysisGroup() const { return IsAnalysisGroup; }
  bool isAnalysis() const { return IsAnalysis; }

  /// isCFGOnlyPass - return true if this pass only looks at the CFG for the
  /// function.
  bool isCFGOnlyPass() const { return IsCFGOnlyPass; }
  
  /// 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.
  ///
  NormalCtor_t getNormalCtor() const {
    return NormalCtor;
  }
  void setNormalCtor(NormalCtor_t Ctor) {
    NormalCtor = Ctor;
  }

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

  /// 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;
  }

  /// getPassInfo - Deprecated API compaatibility function. This function
  /// just returns 'this'.
  ///
  const PassInfo *getPassInfo() const {
    return this;
  }

protected:
  void registerPass();
  void unregisterPass();

private:
  void operator=(const PassInfo &); // do not implement
  PassInfo(const PassInfo &);       // do not implement
};


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

//===---------------------------------------------------------------------------
/// 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:
///
/// static RegisterPass<PassClassName> tmp("passopt", "My Name");
///
template<typename passName>
struct RegisterPass : public PassInfo {

  // Register Pass using default constructor...
  RegisterPass(const char *PassArg, const char *Name, bool CFGOnly = false,
               bool is_analysis = false)
    : PassInfo(Name, PassArg, intptr_t(&passName::ID),
               PassInfo::NormalCtor_t(callDefaultCtor<passName>),
               CFGOnly, is_analysis) {
  }
};


/// 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 second 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 PassInfo {
  PassInfo *InterfaceInfo;
  const PassInfo *ImplementationInfo;
  bool isDefaultImplementation;
protected:
  explicit RegisterAGBase(const char *Name,
                          intptr_t InterfaceID,
                          intptr_t PassID = 0,
                          bool isDefault = false);
};

template<typename Interface, bool Default = false>
struct RegisterAnalysisGroup : public RegisterAGBase {
  explicit RegisterAnalysisGroup(PassInfo &RPB)
    : RegisterAGBase(RPB.getPassName(),
                     intptr_t(&Interface::ID), RPB.getTypeInfo(),
                     Default) {
  }

  explicit RegisterAnalysisGroup(const char *Name)
    : RegisterAGBase(Name, intptr_t(&Interface::ID)) {
  }
};



//===---------------------------------------------------------------------------
/// 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 *) {}

  /// 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 *) {}
};


} // End llvm namespace

#endif

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