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 unsigned MCRegisterInfo::getMatchingSuperReg(unsigned Reg, unsigned SubIdx,
  24                                              const MCRegisterClass *RC) const {
  25   for (MCSuperRegIterator Supers(Reg, this); Supers.isValid(); ++Supers)
  26     if (RC->contains(*Supers) && Reg == getSubReg(*Supers, SubIdx))
  27       return *Supers;
  28   return 0;
  29 }
  30
  31 unsigned MCRegisterInfo::getSubReg(unsigned Reg, unsigned Idx) const {
  32   assert(Idx && Idx < getNumSubRegIndices() &&
  33          "This is not a subregister index");
  34   // Get a pointer to the corresponding SubRegIndices list. This list has the
  35   // name of each sub-register in the same order as MCSubRegIterator.
  36   const uint16_t *SRI = SubRegIndices + get(Reg).SubRegIndices;
  37   for (MCSubRegIterator Subs(Reg, this); Subs.isValid(); ++Subs, ++SRI)
  38     if (*SRI == Idx)
  39       return *Subs;
  40   return 0;
  41 }
  42
  43 unsigned MCRegisterInfo::getSubRegIndex(unsigned Reg, unsigned SubReg) const {
  44   assert(SubReg && SubReg < getNumRegs() && "This is not a register");
  45   // Get a pointer to the corresponding SubRegIndices list. This list has the
  46   // name of each sub-register in the same order as MCSubRegIterator.
  47   const uint16_t *SRI = SubRegIndices + get(Reg).SubRegIndices;
  48   for (MCSubRegIterator Subs(Reg, this); Subs.isValid(); ++Subs, ++SRI)
  49     if (*Subs == SubReg)
  50       return *SRI;
  51   return 0;
  52 }
  53
  54 unsigned MCRegisterInfo::getSubRegIdxSize(unsigned Idx) const {
  55   assert(Idx && Idx < getNumSubRegIndices() &&
  56          "This is not a subregister index");
  57   return SubRegIdxRanges[Idx].Size;
  58 }
  59
  60 unsigned MCRegisterInfo::getSubRegIdxOffset(unsigned Idx) const {
  61   assert(Idx && Idx < getNumSubRegIndices() &&
  62          "This is not a subregister index");
  63   return SubRegIdxRanges[Idx].Offset;
  64 }
  65
  66 int MCRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
  67   const DwarfLLVMRegPair *M = isEH ? EHL2DwarfRegs : L2DwarfRegs;
  68   unsigned Size = isEH ? EHL2DwarfRegsSize : L2DwarfRegsSize;
  69
  70   if (!M)
  71     return -1;
  72   DwarfLLVMRegPair Key = { RegNum, 0 };
  73   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
  74   if (I == M+Size || I->FromReg != RegNum)
  75     return -1;
  76   return I->ToReg;
  77 }
  78
  79 int MCRegisterInfo::getLLVMRegNum(unsigned RegNum, bool isEH) const {
  80   const DwarfLLVMRegPair *M = isEH ? EHDwarf2LRegs : Dwarf2LRegs;
  81   unsigned Size = isEH ? EHDwarf2LRegsSize : Dwarf2LRegsSize;
  82
  83   if (!M)
  84     return -1;
  85   DwarfLLVMRegPair Key = { RegNum, 0 };
  86   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
  87   assert(I != M+Size && I->FromReg == RegNum && "Invalid RegNum");
  88   return I->ToReg;
  89 }
  90
  91 int MCRegisterInfo::getLLVMRegNumFromEH(unsigned RegNum) const {
  92   const DwarfLLVMRegPair *M = EHDwarf2LRegs;
  93   unsigned Size = EHDwarf2LRegsSize;
  94
  95   if (!M)
  96     return -1;
  97   DwarfLLVMRegPair Key = { RegNum, 0 };
  98   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
  99   if (I == M+Size || I->FromReg != RegNum)
 100     return -1;
 101   return I->ToReg;
 102 }
 103
 104 int MCRegisterInfo::getDwarfRegNumFromDwarfEHRegNum(unsigned RegNum) const {
 105   // On ELF platforms, DWARF EH register numbers are the same as DWARF
 106   // other register numbers.  On Darwin x86, they differ and so need to be
 107   // mapped.  The .cfi_* directives accept integer literals as well as
 108   // register names and should generate exactly what the assembly code
 109   // asked for, so there might be DWARF/EH register numbers that don't have
 110   // a corresponding LLVM register number at all.  So if we can't map the
 111   // EH register number to an LLVM register number, assume it's just a
 112   // valid DWARF register number as is.
 113   int LRegNum = getLLVMRegNumFromEH(RegNum);
 114   if (LRegNum != -1)
 115     return getDwarfRegNum(LRegNum, false);
 116   return RegNum;
 117 }
 118
 119 int MCRegisterInfo::getSEHRegNum(unsigned RegNum) const {
 120   const DenseMap<unsigned, int>::const_iterator I = L2SEHRegs.find(RegNum);
 121   if (I == L2SEHRegs.end()) return (int)RegNum;
 122   return I->second;
 123 }
 124
 125 int MCRegisterInfo::getCodeViewRegNum(unsigned RegNum) const {
 126   if (L2CVRegs.empty())
 127     report_fatal_error("target does not implement codeview register mapping");
 128   const DenseMap<unsigned, int>::const_iterator I = L2CVRegs.find(RegNum);
 129   if (I == L2CVRegs.end())
 130     report_fatal_error("unknown codeview register " + (RegNum < getNumRegs()
 131                                                            ? getName(RegNum)
 132                                                            : Twine(RegNum)));
 133   return I->second;
 134 }