llvm/llvm/lib/CodeGen/LiveRangeCalc.cpp

//===- LiveRangeCalc.cpp - Calculate live ranges -------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Implementation of the LiveRangeCalc class.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/LiveRangeCalc.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SlotIndexes.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <iterator>
#include <tuple>
#include <utility>

usingnamespacellvm;

#define DEBUG_TYPE …

// Reserve an address that indicates a value that is known to be "undef".
static VNInfo UndefVNI(0xbad, SlotIndex());

void LiveRangeCalc::resetLiveOutMap() { … }

void LiveRangeCalc::reset(const MachineFunction *mf,
                          SlotIndexes *SI,
                          MachineDominatorTree *MDT,
                          VNInfo::Allocator *VNIA) { … }

void LiveRangeCalc::updateFromLiveIns() { … }

void LiveRangeCalc::extend(LiveRange &LR, SlotIndex Use, unsigned PhysReg,
                           ArrayRef<SlotIndex> Undefs) { … }

// This function is called by a client after using the low-level API to add
// live-out and live-in blocks.  The unique value optimization is not
// available, SplitEditor::transferValues handles that case directly anyway.
void LiveRangeCalc::calculateValues() { … }

bool LiveRangeCalc::isDefOnEntry(LiveRange &LR, ArrayRef<SlotIndex> Undefs,
                                 MachineBasicBlock &MBB, BitVector &DefOnEntry,
                                 BitVector &UndefOnEntry) { … }

bool LiveRangeCalc::findReachingDefs(LiveRange &LR, MachineBasicBlock &UseMBB,
                                     SlotIndex Use, unsigned PhysReg,
                                     ArrayRef<SlotIndex> Undefs) { … }

// This is essentially the same iterative algorithm that SSAUpdater uses,
// except we already have a dominator tree, so we don't have to recompute it.
void LiveRangeCalc::updateSSA() { … }

bool LiveRangeCalc::isJointlyDominated(const MachineBasicBlock *MBB,
                                       ArrayRef<SlotIndex> Defs,
                                       const SlotIndexes &Indexes) { … }