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//===----- llvm/CodeGen/GlobalISel/GISelChangeObserver.h --------*- 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
//
//===----------------------------------------------------------------------===//
/// \file
/// This contains common code to allow clients to notify changes to machine
/// instr.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_GLOBALISEL_GISELCHANGEOBSERVER_H
#define LLVM_CODEGEN_GLOBALISEL_GISELCHANGEOBSERVER_H
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/CodeGen/MachineFunction.h"
namespace llvm {
class MachineInstr;
class MachineRegisterInfo;
/// Abstract class that contains various methods for clients to notify about
/// changes. This should be the preferred way for APIs to notify changes.
/// Typically calling erasingInstr/createdInstr multiple times should not affect
/// the result. The observer would likely need to check if it was already
/// notified earlier (consider using GISelWorkList).
class GISelChangeObserver {
SmallPtrSet<MachineInstr *, 4> ChangingAllUsesOfReg;
public:
virtual ~GISelChangeObserver() = default;
/// An instruction is about to be erased.
virtual void erasingInstr(MachineInstr &MI) = 0;
/// An instruction has been created and inserted into the function.
/// Note that the instruction might not be a fully fledged instruction at this
/// point and won't be if the MachineFunction::Delegate is calling it. This is
/// because the delegate only sees the construction of the MachineInstr before
/// operands have been added.
virtual void createdInstr(MachineInstr &MI) = 0;
/// This instruction is about to be mutated in some way.
virtual void changingInstr(MachineInstr &MI) = 0;
/// This instruction was mutated in some way.
virtual void changedInstr(MachineInstr &MI) = 0;
/// All the instructions using the given register are being changed.
/// For convenience, finishedChangingAllUsesOfReg() will report the completion
/// of the changes. The use list may change between this call and
/// finishedChangingAllUsesOfReg().
void changingAllUsesOfReg(const MachineRegisterInfo &MRI, Register Reg);
/// All instructions reported as changing by changingAllUsesOfReg() have
/// finished being changed.
void finishedChangingAllUsesOfReg();
};
/// Simple wrapper observer that takes several observers, and calls
/// each one for each event. If there are multiple observers (say CSE,
/// Legalizer, Combiner), it's sufficient to register this to the machine
/// function as the delegate.
class GISelObserverWrapper : public MachineFunction::Delegate,
public GISelChangeObserver {
SmallVector<GISelChangeObserver *, 4> Observers;
public:
GISelObserverWrapper() = default;
GISelObserverWrapper(ArrayRef<GISelChangeObserver *> Obs)
: Observers(Obs.begin(), Obs.end()) {}
// Adds an observer.
void addObserver(GISelChangeObserver *O) { Observers.push_back(O); }
// Removes an observer from the list and does nothing if observer is not
// present.
void removeObserver(GISelChangeObserver *O) {
auto It = llvm::find(Observers, O);
if (It != Observers.end())
Observers.erase(It);
}
// API for Observer.
void erasingInstr(MachineInstr &MI) override {
for (auto &O : Observers)
O->erasingInstr(MI);
}
void createdInstr(MachineInstr &MI) override {
for (auto &O : Observers)
O->createdInstr(MI);
}
void changingInstr(MachineInstr &MI) override {
for (auto &O : Observers)
O->changingInstr(MI);
}
void changedInstr(MachineInstr &MI) override {
for (auto &O : Observers)
O->changedInstr(MI);
}
// API for MachineFunction::Delegate
void MF_HandleInsertion(MachineInstr &MI) override { createdInstr(MI); }
void MF_HandleRemoval(MachineInstr &MI) override { erasingInstr(MI); }
};
/// A simple RAII based Delegate installer.
/// Use this in a scope to install a delegate to the MachineFunction and reset
/// it at the end of the scope.
class RAIIDelegateInstaller {
MachineFunction &MF;
MachineFunction::Delegate *Delegate;
public:
RAIIDelegateInstaller(MachineFunction &MF, MachineFunction::Delegate *Del);
~RAIIDelegateInstaller();
};
/// A simple RAII based Observer installer.
/// Use this in a scope to install the Observer to the MachineFunction and reset
/// it at the end of the scope.
class RAIIMFObserverInstaller {
MachineFunction &MF;
public:
RAIIMFObserverInstaller(MachineFunction &MF, GISelChangeObserver &Observer);
~RAIIMFObserverInstaller();
};
/// Class to install both of the above.
class RAIIMFObsDelInstaller {
RAIIDelegateInstaller DelI;
RAIIMFObserverInstaller ObsI;
public:
RAIIMFObsDelInstaller(MachineFunction &MF, GISelObserverWrapper &Wrapper)
: DelI(MF, &Wrapper), ObsI(MF, Wrapper) {}
~RAIIMFObsDelInstaller() = default;
};
} // namespace llvm
#endif
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