lib/MC/MCRegisterInfo.cpp

   1 //===- MC/MCRegisterInfo.cpp - Target Register Description ----------------===//
   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 // This file implements MCRegisterInfo functions.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/MC/MCRegisterInfo.h"
  14 #include "llvm/ADT/DenseMap.h"
  15 #include "llvm/ADT/Twine.h"
  16 #include "llvm/Support/ErrorHandling.h"
  17 #include <algorithm>
  18 #include <cassert>
  19 #include <cstdint>
  20
  21 using namespace llvm;
  22
  23 MCRegister
  24 MCRegisterInfo::getMatchingSuperReg(MCRegister Reg, unsigned SubIdx,
  25                                     const MCRegisterClass *RC) const {
  26   for (MCSuperRegIterator Supers(Reg, this); Supers.isValid(); ++Supers)
  27     if (RC->contains(*Supers) && Reg == getSubReg(*Supers, SubIdx))
  28       return *Supers;
  29   return 0;
  30 }
  31
  32 MCRegister MCRegisterInfo::getSubReg(MCRegister Reg, unsigned Idx) const {
  33   assert(Idx && Idx < getNumSubRegIndices() &&
  34          "This is not a subregister index");
  35   // Get a pointer to the corresponding SubRegIndices list. This list has the
  36   // name of each sub-register in the same order as MCSubRegIterator.
  37   const uint16_t *SRI = SubRegIndices + get(Reg).SubRegIndices;
  38   for (MCSubRegIterator Subs(Reg, this); Subs.isValid(); ++Subs, ++SRI)
  39     if (*SRI == Idx)
  40       return *Subs;
  41   return 0;
  42 }
  43
  44 unsigned MCRegisterInfo::getSubRegIndex(MCRegister Reg,
  45                                         MCRegister SubReg) const {
  46   assert(SubReg && SubReg < getNumRegs() && "This is not a register");
  47   // Get a pointer to the corresponding SubRegIndices list. This list has the
  48   // name of each sub-register in the same order as MCSubRegIterator.
  49   const uint16_t *SRI = SubRegIndices + get(Reg).SubRegIndices;
  50   for (MCSubRegIterator Subs(Reg, this); Subs.isValid(); ++Subs, ++SRI)
  51     if (*Subs == SubReg)
  52       return *SRI;
  53   return 0;
  54 }
  55
  56 unsigned MCRegisterInfo::getSubRegIdxSize(unsigned Idx) const {
  57   assert(Idx && Idx < getNumSubRegIndices() &&
  58          "This is not a subregister index");
  59   return SubRegIdxRanges[Idx].Size;
  60 }
  61
  62 unsigned MCRegisterInfo::getSubRegIdxOffset(unsigned Idx) const {
  63   assert(Idx && Idx < getNumSubRegIndices() &&
  64          "This is not a subregister index");
  65   return SubRegIdxRanges[Idx].Offset;
  66 }
  67
  68 int MCRegisterInfo::getDwarfRegNum(MCRegister RegNum, bool isEH) const {
  69   const DwarfLLVMRegPair *M = isEH ? EHL2DwarfRegs : L2DwarfRegs;
  70   unsigned Size = isEH ? EHL2DwarfRegsSize : L2DwarfRegsSize;
  71
  72   if (!M)
  73     return -1;
  74   DwarfLLVMRegPair Key = { RegNum, 0 };
  75   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
  76   if (I == M+Size || I->FromReg != RegNum)
  77     return -1;
  78   return I->ToReg;
  79 }
  80
  81 Optional<unsigned> MCRegisterInfo::getLLVMRegNum(unsigned RegNum,
  82                                                  bool isEH) const {
  83   const DwarfLLVMRegPair *M = isEH ? EHDwarf2LRegs : Dwarf2LRegs;
  84   unsigned Size = isEH ? EHDwarf2LRegsSize : Dwarf2LRegsSize;
  85
  86   if (!M)
  87     return None;
  88   DwarfLLVMRegPair Key = { RegNum, 0 };
  89   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
  90   if (I != M + Size && I->FromReg == RegNum)
  91     return I->ToReg;
  92   return None;
  93 }
  94
  95 int MCRegisterInfo::getDwarfRegNumFromDwarfEHRegNum(unsigned RegNum) const {
  96   // On ELF platforms, DWARF EH register numbers are the same as DWARF
  97   // other register numbers.  On Darwin x86, they differ and so need to be
  98   // mapped.  The .cfi_* directives accept integer literals as well as
  99   // register names and should generate exactly what the assembly code
 100   // asked for, so there might be DWARF/EH register numbers that don't have
 101   // a corresponding LLVM register number at all.  So if we can't map the
 102   // EH register number to an LLVM register number, assume it's just a
 103   // valid DWARF register number as is.
 104   if (Optional<unsigned> LRegNum = getLLVMRegNum(RegNum, true))
 105     return getDwarfRegNum(*LRegNum, false);
 106   return RegNum;
 107 }
 108
 109 int MCRegisterInfo::getSEHRegNum(MCRegister RegNum) const {
 110   const DenseMap<MCRegister, int>::const_iterator I = L2SEHRegs.find(RegNum);
 111   if (I == L2SEHRegs.end()) return (int)RegNum;
 112   return I->second;
 113 }
 114
 115 int MCRegisterInfo::getCodeViewRegNum(MCRegister RegNum) const {
 116   if (L2CVRegs.empty())
 117     report_fatal_error("target does not implement codeview register mapping");
 118   const DenseMap<MCRegister, int>::const_iterator I = L2CVRegs.find(RegNum);
 119   if (I == L2CVRegs.end())
 120     report_fatal_error("unknown codeview register " + (RegNum < getNumRegs()
 121                                                            ? getName(RegNum)
 122                                                            : Twine(RegNum)));
 123   return I->second;
 124 }