llvm/llvm/include/llvm/MCA/HardwareUnits/ResourceManager.h

//===--------------------- ResourceManager.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
///
/// The classes here represent processor resource units and their management
/// strategy.  These classes are managed by the Scheduler.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_MCA_HARDWAREUNITS_RESOURCEMANAGER_H
#define LLVM_MCA_HARDWAREUNITS_RESOURCEMANAGER_H

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/MC/MCSchedule.h"
#include "llvm/MCA/Instruction.h"
#include "llvm/MCA/Support.h"

namespace llvm {
namespace mca {

/// Used to notify the internal state of a processor resource.
///
/// A processor resource is available if it is not reserved, and there are
/// available slots in the buffer.  A processor resource is unavailable if it
/// is either reserved, or the associated buffer is full. A processor resource
/// with a buffer size of -1 is always available if it is not reserved.
///
/// Values of type ResourceStateEvent are returned by method
/// ResourceManager::canBeDispatched()
///
/// The naming convention for resource state events is:
///  * Event names start with prefix RS_
///  * Prefix RS_ is followed by a string describing the actual resource state.
enum ResourceStateEvent { … };

/// Resource allocation strategy used by hardware scheduler resources.
class ResourceStrategy { … };

/// Default resource allocation strategy used by processor resource groups and
/// processor resources with multiple units.
class DefaultResourceStrategy final : public ResourceStrategy { … };

/// A processor resource descriptor.
///
/// There is an instance of this class for every processor resource defined by
/// the machine scheduling model.
/// Objects of class ResourceState dynamically track the usage of processor
/// resource units.
class ResourceState { … };

/// A resource unit identifier.
///
/// This is used to identify a specific processor resource unit using a pair
/// of indices where the 'first' index is a processor resource mask, and the
/// 'second' index is an index for a "sub-resource" (i.e. unit).
ResourceRef;

// First: a MCProcResourceDesc index identifying a buffered resource.
// Second: max number of buffer entries used in this resource.
BufferUsageEntry;

/// A resource manager for processor resource units and groups.
///
/// This class owns all the ResourceState objects, and it is responsible for
/// acting on requests from a Scheduler by updating the internal state of
/// ResourceState objects.
/// This class doesn't know about instruction itineraries and functional units.
/// In future, it can be extended to support itineraries too through the same
/// public interface.
class ResourceManager { … };
} // namespace mca
} // namespace llvm

#endif // LLVM_MCA_HARDWAREUNITS_RESOURCEMANAGER_H