reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
//===-- llvm/CodeGen/AllocationOrder.cpp - Allocation Order ---------------===//
//
// 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 an allocation order for virtual registers.
//
// The preferred allocation order for a virtual register depends on allocation
// hints and target hooks. The AllocationOrder class encapsulates all of that.
//
//===----------------------------------------------------------------------===//

#include "AllocationOrder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterClassInfo.h"
#include "llvm/CodeGen/VirtRegMap.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm;

#define DEBUG_TYPE "regalloc"

// Compare VirtRegMap::getRegAllocPref().
AllocationOrder::AllocationOrder(unsigned VirtReg,
                                 const VirtRegMap &VRM,
                                 const RegisterClassInfo &RegClassInfo,
                                 const LiveRegMatrix *Matrix)
  : Pos(0), HardHints(false) {
  const MachineFunction &MF = VRM.getMachineFunction();
  const TargetRegisterInfo *TRI = &VRM.getTargetRegInfo();
  Order = RegClassInfo.getOrder(MF.getRegInfo().getRegClass(VirtReg));
  if (TRI->getRegAllocationHints(VirtReg, Order, Hints, MF, &VRM, Matrix))
    HardHints = true;
  rewind();

  LLVM_DEBUG({
    if (!Hints.empty()) {
      dbgs() << "hints:";
      for (unsigned I = 0, E = Hints.size(); I != E; ++I)
        dbgs() << ' ' << printReg(Hints[I], TRI);
      dbgs() << '\n';
    }
  });
#ifndef NDEBUG
  for (unsigned I = 0, E = Hints.size(); I != E; ++I)
    assert(is_contained(Order, Hints[I]) &&
           "Target hint is outside allocation order.");
#endif
}