llvm/llvm/lib/CodeGen/LiveIntervalUnion.cpp

//===- LiveIntervalUnion.cpp - Live interval union data structure ---------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// LiveIntervalUnion represents a coalesced set of live intervals. This may be
// used during coalescing to represent a congruence class, or during register
// allocation to model liveness of a physical register.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/LiveIntervalUnion.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdlib>

usingnamespacellvm;

#define DEBUG_TYPE …

// Merge a LiveInterval's segments. Guarantee no overlaps.
void LiveIntervalUnion::unify(const LiveInterval &VirtReg,
                              const LiveRange &Range) { … }

// Remove a live virtual register's segments from this union.
void LiveIntervalUnion::extract(const LiveInterval &VirtReg,
                                const LiveRange &Range) { … }

void
LiveIntervalUnion::print(raw_ostream &OS, const TargetRegisterInfo *TRI) const { … }

#ifndef NDEBUG
// Verify the live intervals in this union and add them to the visited set.
void LiveIntervalUnion::verify(LiveVirtRegBitSet& VisitedVRegs) {
  for (SegmentIter SI = Segments.begin(); SI.valid(); ++SI)
    VisitedVRegs.set(SI.value()->reg());
}
#endif //!NDEBUG

const LiveInterval *LiveIntervalUnion::getOneVReg() const { … }

// Scan the vector of interfering virtual registers in this union. Assume it's
// quite small.
bool LiveIntervalUnion::Query::isSeenInterference(
    const LiveInterval *VirtReg) const { … }

// Collect virtual registers in this union that interfere with this
// query's live virtual register.
//
// The query state is one of:
//
// 1. CheckedFirstInterference == false: Iterators are uninitialized.
// 2. SeenAllInterferences == true: InterferingVRegs complete, iterators unused.
// 3. Iterators left at the last seen intersection.
//
unsigned
LiveIntervalUnion::Query::collectInterferingVRegs(unsigned MaxInterferingRegs) { … }

void LiveIntervalUnion::Array::init(LiveIntervalUnion::Allocator &Alloc,
                                    unsigned NSize) { … }

void LiveIntervalUnion::Array::clear() { … }