1 //===- MC/MCRegisterInfo.cpp - Target Register Description ----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements MCRegisterInfo functions.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/MC/MCRegisterInfo.h"
15 #include "llvm/ADT/DenseMap.h"
16 #include "llvm/ADT/Twine.h"
17 #include "llvm/Support/ErrorHandling.h"
18 #include <algorithm>
19 #include <cassert>
20 #include <cstdint>
21 
22 using namespace llvm;
23 
24 unsigned MCRegisterInfo::getMatchingSuperReg(unsigned 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 unsigned MCRegisterInfo::getSubReg(unsigned 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(unsigned Reg, unsigned SubReg) const {
45   assert(SubReg && SubReg < getNumRegs() && "This is not a register");
46   // Get a pointer to the corresponding SubRegIndices list. This list has the
47   // name of each sub-register in the same order as MCSubRegIterator.
48   const uint16_t *SRI = SubRegIndices + get(Reg).SubRegIndices;
49   for (MCSubRegIterator Subs(Reg, this); Subs.isValid(); ++Subs, ++SRI)
50     if (*Subs == SubReg)
51       return *SRI;
52   return 0;
53 }
54 
55 unsigned MCRegisterInfo::getSubRegIdxSize(unsigned Idx) const {
56   assert(Idx && Idx < getNumSubRegIndices() &&
57          "This is not a subregister index");
58   return SubRegIdxRanges[Idx].Size;
59 }
60 
61 unsigned MCRegisterInfo::getSubRegIdxOffset(unsigned Idx) const {
62   assert(Idx && Idx < getNumSubRegIndices() &&
63          "This is not a subregister index");
64   return SubRegIdxRanges[Idx].Offset;
65 }
66 
67 int MCRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
68   const DwarfLLVMRegPair *M = isEH ? EHL2DwarfRegs : L2DwarfRegs;
69   unsigned Size = isEH ? EHL2DwarfRegsSize : L2DwarfRegsSize;
70 
71   if (!M)
72     return -1;
73   DwarfLLVMRegPair Key = { RegNum, 0 };
74   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
75   if (I == M+Size || I->FromReg != RegNum)
76     return -1;
77   return I->ToReg;
78 }
79 
80 int MCRegisterInfo::getLLVMRegNum(unsigned RegNum, bool isEH) const {
81   const DwarfLLVMRegPair *M = isEH ? EHDwarf2LRegs : Dwarf2LRegs;
82   unsigned Size = isEH ? EHDwarf2LRegsSize : Dwarf2LRegsSize;
83 
84   if (!M)
85     return -1;
86   DwarfLLVMRegPair Key = { RegNum, 0 };
87   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
88   assert(I != M+Size && I->FromReg == RegNum && "Invalid RegNum");
89   return I->ToReg;
90 }
91 
92 int MCRegisterInfo::getLLVMRegNumFromEH(unsigned RegNum) const {
93   const DwarfLLVMRegPair *M = EHDwarf2LRegs;
94   unsigned Size = EHDwarf2LRegsSize;
95 
96   if (!M)
97     return -1;
98   DwarfLLVMRegPair Key = { RegNum, 0 };
99   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
100   if (I == M+Size || I->FromReg != RegNum)
101     return -1;
102   return I->ToReg;
103 }
104 
105 int MCRegisterInfo::getDwarfRegNumFromDwarfEHRegNum(unsigned RegNum) const {
106   // On ELF platforms, DWARF EH register numbers are the same as DWARF
107   // other register numbers.  On Darwin x86, they differ and so need to be
108   // mapped.  The .cfi_* directives accept integer literals as well as
109   // register names and should generate exactly what the assembly code
110   // asked for, so there might be DWARF/EH register numbers that don't have
111   // a corresponding LLVM register number at all.  So if we can't map the
112   // EH register number to an LLVM register number, assume it's just a
113   // valid DWARF register number as is.
114   int LRegNum = getLLVMRegNumFromEH(RegNum);
115   if (LRegNum != -1)
116     return getDwarfRegNum(LRegNum, false);
117   return RegNum;
118 }
119 
120 int MCRegisterInfo::getSEHRegNum(unsigned RegNum) const {
121   const DenseMap<unsigned, int>::const_iterator I = L2SEHRegs.find(RegNum);
122   if (I == L2SEHRegs.end()) return (int)RegNum;
123   return I->second;
124 }
125 
126 int MCRegisterInfo::getCodeViewRegNum(unsigned RegNum) const {
127   if (L2CVRegs.empty())
128     report_fatal_error("target does not implement codeview register mapping");
129   const DenseMap<unsigned, int>::const_iterator I = L2CVRegs.find(RegNum);
130   if (I == L2CVRegs.end())
131     report_fatal_error("unknown codeview register " + (RegNum < getNumRegs()
132                                                            ? getName(RegNum)
133                                                            : Twine(RegNum)));
134   return I->second;
135 }
136