//===- LiveStacks.h - Live Stack Slot Analysis ------------------*- 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 implements the live stack slot analysis pass. It is analogous to
 
// live interval analysis except it's analyzing liveness of stack slots rather
 
// than registers.
 
//
 
//===----------------------------------------------------------------------===//
 
 
 
#ifndef LLVM_CODEGEN_LIVESTACKS_H
 
#define LLVM_CODEGEN_LIVESTACKS_H
 
 
 
#include "llvm/CodeGen/LiveInterval.h"
 
#include "llvm/CodeGen/MachineFunctionPass.h"
 
#include "llvm/InitializePasses.h"
 
#include "llvm/PassRegistry.h"
 
#include <cassert>
 
#include <map>
 
#include <unordered_map>
 
 
 
namespace llvm {
 
 
 
class AnalysisUsage;
 
class MachineFunction;
 
class Module;
 
class raw_ostream;
 
class TargetRegisterClass;
 
class TargetRegisterInfo;
 
 
 
class LiveStacks : public MachineFunctionPass {
 
  const TargetRegisterInfo *TRI;
 
 
 
  /// Special pool allocator for VNInfo's (LiveInterval val#).
 
  ///
 
  VNInfo::Allocator VNInfoAllocator;
 
 
 
  /// S2IMap - Stack slot indices to live interval mapping.
 
  using SS2IntervalMap = std::unordered_map<int, LiveInterval>;
 
  SS2IntervalMap S2IMap;
 
 
 
  /// S2RCMap - Stack slot indices to register class mapping.
 
  std::map<int, const TargetRegisterClass *> S2RCMap;
 
 
 
public:
 
  static char ID; // Pass identification, replacement for typeid
 
 
 
  LiveStacks() : MachineFunctionPass(ID) {
 
    initializeLiveStacksPass(*PassRegistry::getPassRegistry());
 
  }
 
 
 
  using iterator = SS2IntervalMap::iterator;
 
  using const_iterator = SS2IntervalMap::const_iterator;
 
 
 
  const_iterator begin() const { return S2IMap.begin(); }
 
  const_iterator end() const { return S2IMap.end(); }
 
  iterator begin() { return S2IMap.begin(); }
 
  iterator end() { return S2IMap.end(); }
 
 
 
  unsigned getNumIntervals() const { return (unsigned)S2IMap.size(); }
 
 
 
  LiveInterval &getOrCreateInterval(int Slot, const TargetRegisterClass *RC);
 
 
 
  LiveInterval &getInterval(int Slot) {
 
    assert(Slot >= 0 && "Spill slot indice must be >= 0");
 
    SS2IntervalMap::iterator I = S2IMap.find(Slot);
 
    assert(I != S2IMap.end() && "Interval does not exist for stack slot");
 
    return I->second;
 
  }
 
 
 
  const LiveInterval &getInterval(int Slot) const {
 
    assert(Slot >= 0 && "Spill slot indice must be >= 0");
 
    SS2IntervalMap::const_iterator I = S2IMap.find(Slot);
 
    assert(I != S2IMap.end() && "Interval does not exist for stack slot");
 
    return I->second;
 
  }
 
 
 
  bool hasInterval(int Slot) const { return S2IMap.count(Slot); }
 
 
 
  const TargetRegisterClass *getIntervalRegClass(int Slot) const {
 
    assert(Slot >= 0 && "Spill slot indice must be >= 0");
 
    std::map<int, const TargetRegisterClass *>::const_iterator I =
 
        S2RCMap.find(Slot);
 
    assert(I != S2RCMap.end() &&
 
           "Register class info does not exist for stack slot");
 
    return I->second;
 
  }
 
 
 
  VNInfo::Allocator &getVNInfoAllocator() { return VNInfoAllocator; }
 
 
 
  void getAnalysisUsage(AnalysisUsage &AU) const override;
 
  void releaseMemory() override;
 
 
 
  /// runOnMachineFunction - pass entry point
 
  bool runOnMachineFunction(MachineFunction &) override;
 
 
 
  /// print - Implement the dump method.
 
  void print(raw_ostream &O, const Module * = nullptr) const override;
 
};
 
 
 
} // end namespace llvm
 
 
 
#endif