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      1 //===-- RegisterAliasing.cpp ------------------------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 
      9 #include "RegisterAliasing.h"
     10 
     11 namespace llvm {
     12 namespace exegesis {
     13 
     14 BitVector getAliasedBits(const MCRegisterInfo &RegInfo,
     15                          const BitVector &SourceBits) {
     16   BitVector AliasedBits(RegInfo.getNumRegs());
     17   for (const size_t PhysReg : SourceBits.set_bits()) {
     18     using RegAliasItr = MCRegAliasIterator;
     19     for (auto Itr = RegAliasItr(PhysReg, &RegInfo, true); Itr.isValid();
     20          ++Itr) {
     21       AliasedBits.set(*Itr);
     22     }
     23   }
     24   return AliasedBits;
     25 }
     26 
     27 RegisterAliasingTracker::RegisterAliasingTracker(const MCRegisterInfo &RegInfo)
     28     : SourceBits(RegInfo.getNumRegs()), AliasedBits(RegInfo.getNumRegs()),
     29       Origins(RegInfo.getNumRegs()) {}
     30 
     31 RegisterAliasingTracker::RegisterAliasingTracker(
     32     const MCRegisterInfo &RegInfo, const BitVector &ReservedReg,
     33     const MCRegisterClass &RegClass)
     34     : RegisterAliasingTracker(RegInfo) {
     35   for (MCPhysReg PhysReg : RegClass)
     36     if (!ReservedReg[PhysReg]) // Removing reserved registers.
     37       SourceBits.set(PhysReg);
     38   FillOriginAndAliasedBits(RegInfo, SourceBits);
     39 }
     40 
     41 RegisterAliasingTracker::RegisterAliasingTracker(const MCRegisterInfo &RegInfo,
     42                                                  const MCPhysReg PhysReg)
     43     : RegisterAliasingTracker(RegInfo) {
     44   SourceBits.set(PhysReg);
     45   FillOriginAndAliasedBits(RegInfo, SourceBits);
     46 }
     47 
     48 void RegisterAliasingTracker::FillOriginAndAliasedBits(
     49     const MCRegisterInfo &RegInfo, const BitVector &SourceBits) {
     50   using RegAliasItr = MCRegAliasIterator;
     51   for (const size_t PhysReg : SourceBits.set_bits()) {
     52     for (auto Itr = RegAliasItr(PhysReg, &RegInfo, true); Itr.isValid();
     53          ++Itr) {
     54       AliasedBits.set(*Itr);
     55       Origins[*Itr] = PhysReg;
     56     }
     57   }
     58 }
     59 
     60 RegisterAliasingTrackerCache::RegisterAliasingTrackerCache(
     61     const MCRegisterInfo &RegInfo, const BitVector &ReservedReg)
     62     : RegInfo(RegInfo), ReservedReg(ReservedReg),
     63       EmptyRegisters(RegInfo.getNumRegs()) {}
     64 
     65 const RegisterAliasingTracker &
     66 RegisterAliasingTrackerCache::getRegister(MCPhysReg PhysReg) const {
     67   auto &Found = Registers[PhysReg];
     68   if (!Found)
     69     Found.reset(new RegisterAliasingTracker(RegInfo, PhysReg));
     70   return *Found;
     71 }
     72 
     73 const RegisterAliasingTracker &
     74 RegisterAliasingTrackerCache::getRegisterClass(unsigned RegClassIndex) const {
     75   auto &Found = RegisterClasses[RegClassIndex];
     76   const auto &RegClass = RegInfo.getRegClass(RegClassIndex);
     77   if (!Found)
     78     Found.reset(new RegisterAliasingTracker(RegInfo, ReservedReg, RegClass));
     79   return *Found;
     80 }
     81 
     82 std::string debugString(const MCRegisterInfo &RegInfo, const BitVector &Regs) {
     83   std::string Result;
     84   for (const unsigned Reg : Regs.set_bits()) {
     85     Result.append(RegInfo.getName(Reg));
     86     Result.push_back(' ');
     87   }
     88   return Result;
     89 }
     90 
     91 } // namespace exegesis
     92 } // namespace llvm
     93