1 //===-- X86Disassembler.cpp - Disassembler for x86 and x86_64 -------------===//
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 is part of the X86 Disassembler.
11 // It contains code to translate the data produced by the decoder into
12 //  MCInsts.
13 //
14 //
15 // The X86 disassembler is a table-driven disassembler for the 16-, 32-, and
16 // 64-bit X86 instruction sets.  The main decode sequence for an assembly
17 // instruction in this disassembler is:
18 //
19 // 1. Read the prefix bytes and determine the attributes of the instruction.
20 //    These attributes, recorded in enum attributeBits
21 //    (X86DisassemblerDecoderCommon.h), form a bitmask.  The table CONTEXTS_SYM
22 //    provides a mapping from bitmasks to contexts, which are represented by
23 //    enum InstructionContext (ibid.).
24 //
25 // 2. Read the opcode, and determine what kind of opcode it is.  The
26 //    disassembler distinguishes four kinds of opcodes, which are enumerated in
27 //    OpcodeType (X86DisassemblerDecoderCommon.h): one-byte (0xnn), two-byte
28 //    (0x0f 0xnn), three-byte-38 (0x0f 0x38 0xnn), or three-byte-3a
29 //    (0x0f 0x3a 0xnn).  Mandatory prefixes are treated as part of the context.
30 //
31 // 3. Depending on the opcode type, look in one of four ClassDecision structures
32 //    (X86DisassemblerDecoderCommon.h).  Use the opcode class to determine which
33 //    OpcodeDecision (ibid.) to look the opcode in.  Look up the opcode, to get
34 //    a ModRMDecision (ibid.).
35 //
36 // 4. Some instructions, such as escape opcodes or extended opcodes, or even
37 //    instructions that have ModRM*Reg / ModRM*Mem forms in LLVM, need the
38 //    ModR/M byte to complete decode.  The ModRMDecision's type is an entry from
39 //    ModRMDecisionType (X86DisassemblerDecoderCommon.h) that indicates if the
40 //    ModR/M byte is required and how to interpret it.
41 //
42 // 5. After resolving the ModRMDecision, the disassembler has a unique ID
43 //    of type InstrUID (X86DisassemblerDecoderCommon.h).  Looking this ID up in
44 //    INSTRUCTIONS_SYM yields the name of the instruction and the encodings and
45 //    meanings of its operands.
46 //
47 // 6. For each operand, its encoding is an entry from OperandEncoding
48 //    (X86DisassemblerDecoderCommon.h) and its type is an entry from
49 //    OperandType (ibid.).  The encoding indicates how to read it from the
50 //    instruction; the type indicates how to interpret the value once it has
51 //    been read.  For example, a register operand could be stored in the R/M
52 //    field of the ModR/M byte, the REG field of the ModR/M byte, or added to
53 //    the main opcode.  This is orthogonal from its meaning (an GPR or an XMM
54 //    register, for instance).  Given this information, the operands can be
55 //    extracted and interpreted.
56 //
57 // 7. As the last step, the disassembler translates the instruction information
58 //    and operands into a format understandable by the client - in this case, an
59 //    MCInst for use by the MC infrastructure.
60 //
61 // The disassembler is broken broadly into two parts: the table emitter that
62 // emits the instruction decode tables discussed above during compilation, and
63 // the disassembler itself.  The table emitter is documented in more detail in
64 // utils/TableGen/X86DisassemblerEmitter.h.
65 //
66 // X86Disassembler.cpp contains the code responsible for step 7, and for
67 //   invoking the decoder to execute steps 1-6.
68 // X86DisassemblerDecoderCommon.h contains the definitions needed by both the
69 //   table emitter and the disassembler.
70 // X86DisassemblerDecoder.h contains the public interface of the decoder,
71 //   factored out into C for possible use by other projects.
72 // X86DisassemblerDecoder.c contains the source code of the decoder, which is
73 //   responsible for steps 1-6.
74 //
75 //===----------------------------------------------------------------------===//
76 
77 #include "MCTargetDesc/X86BaseInfo.h"
78 #include "MCTargetDesc/X86MCTargetDesc.h"
79 #include "X86DisassemblerDecoder.h"
80 #include "llvm/MC/MCContext.h"
81 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
82 #include "llvm/MC/MCExpr.h"
83 #include "llvm/MC/MCInst.h"
84 #include "llvm/MC/MCInstrInfo.h"
85 #include "llvm/MC/MCSubtargetInfo.h"
86 #include "llvm/Support/Debug.h"
87 #include "llvm/Support/TargetRegistry.h"
88 #include "llvm/Support/raw_ostream.h"
89 
90 using namespace llvm;
91 using namespace llvm::X86Disassembler;
92 
93 #define DEBUG_TYPE "x86-disassembler"
94 
95 void llvm::X86Disassembler::Debug(const char *file, unsigned line,
96                                   const char *s) {
97   dbgs() << file << ":" << line << ": " << s;
98 }
99 
100 StringRef llvm::X86Disassembler::GetInstrName(unsigned Opcode,
101                                                 const void *mii) {
102   const MCInstrInfo *MII = static_cast<const MCInstrInfo *>(mii);
103   return MII->getName(Opcode);
104 }
105 
106 #define debug(s) DEBUG(Debug(__FILE__, __LINE__, s));
107 
108 namespace llvm {
109 
110 // Fill-ins to make the compiler happy.  These constants are never actually
111 //   assigned; they are just filler to make an automatically-generated switch
112 //   statement work.
113 namespace X86 {
114   enum {
115     BX_SI = 500,
116     BX_DI = 501,
117     BP_SI = 502,
118     BP_DI = 503,
119     sib   = 504,
120     sib64 = 505
121   };
122 }
123 
124 }
125 
126 static bool translateInstruction(MCInst &target,
127                                 InternalInstruction &source,
128                                 const MCDisassembler *Dis);
129 
130 namespace {
131 
132 /// Generic disassembler for all X86 platforms. All each platform class should
133 /// have to do is subclass the constructor, and provide a different
134 /// disassemblerMode value.
135 class X86GenericDisassembler : public MCDisassembler {
136   std::unique_ptr<const MCInstrInfo> MII;
137 public:
138   X86GenericDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx,
139                          std::unique_ptr<const MCInstrInfo> MII);
140 public:
141   DecodeStatus getInstruction(MCInst &instr, uint64_t &size,
142                               ArrayRef<uint8_t> Bytes, uint64_t Address,
143                               raw_ostream &vStream,
144                               raw_ostream &cStream) const override;
145 
146 private:
147   DisassemblerMode              fMode;
148 };
149 
150 }
151 
152 X86GenericDisassembler::X86GenericDisassembler(
153                                          const MCSubtargetInfo &STI,
154                                          MCContext &Ctx,
155                                          std::unique_ptr<const MCInstrInfo> MII)
156   : MCDisassembler(STI, Ctx), MII(std::move(MII)) {
157   const FeatureBitset &FB = STI.getFeatureBits();
158   if (FB[X86::Mode16Bit]) {
159     fMode = MODE_16BIT;
160     return;
161   } else if (FB[X86::Mode32Bit]) {
162     fMode = MODE_32BIT;
163     return;
164   } else if (FB[X86::Mode64Bit]) {
165     fMode = MODE_64BIT;
166     return;
167   }
168 
169   llvm_unreachable("Invalid CPU mode");
170 }
171 
172 namespace {
173 struct Region {
174   ArrayRef<uint8_t> Bytes;
175   uint64_t Base;
176   Region(ArrayRef<uint8_t> Bytes, uint64_t Base) : Bytes(Bytes), Base(Base) {}
177 };
178 } // end anonymous namespace
179 
180 /// A callback function that wraps the readByte method from Region.
181 ///
182 /// @param Arg      - The generic callback parameter.  In this case, this should
183 ///                   be a pointer to a Region.
184 /// @param Byte     - A pointer to the byte to be read.
185 /// @param Address  - The address to be read.
186 static int regionReader(const void *Arg, uint8_t *Byte, uint64_t Address) {
187   auto *R = static_cast<const Region *>(Arg);
188   ArrayRef<uint8_t> Bytes = R->Bytes;
189   unsigned Index = Address - R->Base;
190   if (Bytes.size() <= Index)
191     return -1;
192   *Byte = Bytes[Index];
193   return 0;
194 }
195 
196 /// logger - a callback function that wraps the operator<< method from
197 ///   raw_ostream.
198 ///
199 /// @param arg      - The generic callback parameter.  This should be a pointe
200 ///                   to a raw_ostream.
201 /// @param log      - A string to be logged.  logger() adds a newline.
202 static void logger(void* arg, const char* log) {
203   if (!arg)
204     return;
205 
206   raw_ostream &vStream = *(static_cast<raw_ostream*>(arg));
207   vStream << log << "\n";
208 }
209 
210 //
211 // Public interface for the disassembler
212 //
213 
214 MCDisassembler::DecodeStatus X86GenericDisassembler::getInstruction(
215     MCInst &Instr, uint64_t &Size, ArrayRef<uint8_t> Bytes, uint64_t Address,
216     raw_ostream &VStream, raw_ostream &CStream) const {
217   CommentStream = &CStream;
218 
219   InternalInstruction InternalInstr;
220 
221   dlog_t LoggerFn = logger;
222   if (&VStream == &nulls())
223     LoggerFn = nullptr; // Disable logging completely if it's going to nulls().
224 
225   Region R(Bytes, Address);
226 
227   int Ret = decodeInstruction(&InternalInstr, regionReader, (const void *)&R,
228                               LoggerFn, (void *)&VStream,
229                               (const void *)MII.get(), Address, fMode);
230 
231   if (Ret) {
232     Size = InternalInstr.readerCursor - Address;
233     return Fail;
234   } else {
235     Size = InternalInstr.length;
236     bool Ret = translateInstruction(Instr, InternalInstr, this);
237     if (!Ret) {
238       unsigned Flags = X86::IP_NO_PREFIX;
239       if (InternalInstr.hasAdSize)
240         Flags |= X86::IP_HAS_AD_SIZE;
241       if (!InternalInstr.mandatoryPrefix) {
242         if (InternalInstr.hasOpSize)
243           Flags |= X86::IP_HAS_OP_SIZE;
244         if (InternalInstr.repeatPrefix == 0xf2)
245           Flags |= X86::IP_HAS_REPEAT_NE;
246         else if (InternalInstr.repeatPrefix == 0xf3 &&
247                  // It should not be 'pause' f3 90
248                  InternalInstr.opcode != 0x90)
249           Flags |= X86::IP_HAS_REPEAT;
250       }
251       Instr.setFlags(Flags);
252     }
253     return (!Ret) ? Success : Fail;
254   }
255 }
256 
257 //
258 // Private code that translates from struct InternalInstructions to MCInsts.
259 //
260 
261 /// translateRegister - Translates an internal register to the appropriate LLVM
262 ///   register, and appends it as an operand to an MCInst.
263 ///
264 /// @param mcInst     - The MCInst to append to.
265 /// @param reg        - The Reg to append.
266 static void translateRegister(MCInst &mcInst, Reg reg) {
267 #define ENTRY(x) X86::x,
268   uint8_t llvmRegnums[] = {
269     ALL_REGS
270     0
271   };
272 #undef ENTRY
273 
274   uint8_t llvmRegnum = llvmRegnums[reg];
275   mcInst.addOperand(MCOperand::createReg(llvmRegnum));
276 }
277 
278 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
279 /// immediate Value in the MCInst.
280 ///
281 /// @param Value      - The immediate Value, has had any PC adjustment made by
282 ///                     the caller.
283 /// @param isBranch   - If the instruction is a branch instruction
284 /// @param Address    - The starting address of the instruction
285 /// @param Offset     - The byte offset to this immediate in the instruction
286 /// @param Width      - The byte width of this immediate in the instruction
287 ///
288 /// If the getOpInfo() function was set when setupForSymbolicDisassembly() was
289 /// called then that function is called to get any symbolic information for the
290 /// immediate in the instruction using the Address, Offset and Width.  If that
291 /// returns non-zero then the symbolic information it returns is used to create
292 /// an MCExpr and that is added as an operand to the MCInst.  If getOpInfo()
293 /// returns zero and isBranch is true then a symbol look up for immediate Value
294 /// is done and if a symbol is found an MCExpr is created with that, else
295 /// an MCExpr with the immediate Value is created.  This function returns true
296 /// if it adds an operand to the MCInst and false otherwise.
297 static bool tryAddingSymbolicOperand(int64_t Value, bool isBranch,
298                                      uint64_t Address, uint64_t Offset,
299                                      uint64_t Width, MCInst &MI,
300                                      const MCDisassembler *Dis) {
301   return Dis->tryAddingSymbolicOperand(MI, Value, Address, isBranch,
302                                        Offset, Width);
303 }
304 
305 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
306 /// referenced by a load instruction with the base register that is the rip.
307 /// These can often be addresses in a literal pool.  The Address of the
308 /// instruction and its immediate Value are used to determine the address
309 /// being referenced in the literal pool entry.  The SymbolLookUp call back will
310 /// return a pointer to a literal 'C' string if the referenced address is an
311 /// address into a section with 'C' string literals.
312 static void tryAddingPcLoadReferenceComment(uint64_t Address, uint64_t Value,
313                                             const void *Decoder) {
314   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
315   Dis->tryAddingPcLoadReferenceComment(Value, Address);
316 }
317 
318 static const uint8_t segmentRegnums[SEG_OVERRIDE_max] = {
319   0,        // SEG_OVERRIDE_NONE
320   X86::CS,
321   X86::SS,
322   X86::DS,
323   X86::ES,
324   X86::FS,
325   X86::GS
326 };
327 
328 /// translateSrcIndex   - Appends a source index operand to an MCInst.
329 ///
330 /// @param mcInst       - The MCInst to append to.
331 /// @param insn         - The internal instruction.
332 static bool translateSrcIndex(MCInst &mcInst, InternalInstruction &insn) {
333   unsigned baseRegNo;
334 
335   if (insn.mode == MODE_64BIT)
336     baseRegNo = insn.hasAdSize ? X86::ESI : X86::RSI;
337   else if (insn.mode == MODE_32BIT)
338     baseRegNo = insn.hasAdSize ? X86::SI : X86::ESI;
339   else {
340     assert(insn.mode == MODE_16BIT);
341     baseRegNo = insn.hasAdSize ? X86::ESI : X86::SI;
342   }
343   MCOperand baseReg = MCOperand::createReg(baseRegNo);
344   mcInst.addOperand(baseReg);
345 
346   MCOperand segmentReg;
347   segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]);
348   mcInst.addOperand(segmentReg);
349   return false;
350 }
351 
352 /// translateDstIndex   - Appends a destination index operand to an MCInst.
353 ///
354 /// @param mcInst       - The MCInst to append to.
355 /// @param insn         - The internal instruction.
356 
357 static bool translateDstIndex(MCInst &mcInst, InternalInstruction &insn) {
358   unsigned baseRegNo;
359 
360   if (insn.mode == MODE_64BIT)
361     baseRegNo = insn.hasAdSize ? X86::EDI : X86::RDI;
362   else if (insn.mode == MODE_32BIT)
363     baseRegNo = insn.hasAdSize ? X86::DI : X86::EDI;
364   else {
365     assert(insn.mode == MODE_16BIT);
366     baseRegNo = insn.hasAdSize ? X86::EDI : X86::DI;
367   }
368   MCOperand baseReg = MCOperand::createReg(baseRegNo);
369   mcInst.addOperand(baseReg);
370   return false;
371 }
372 
373 /// translateImmediate  - Appends an immediate operand to an MCInst.
374 ///
375 /// @param mcInst       - The MCInst to append to.
376 /// @param immediate    - The immediate value to append.
377 /// @param operand      - The operand, as stored in the descriptor table.
378 /// @param insn         - The internal instruction.
379 static void translateImmediate(MCInst &mcInst, uint64_t immediate,
380                                const OperandSpecifier &operand,
381                                InternalInstruction &insn,
382                                const MCDisassembler *Dis) {
383   // Sign-extend the immediate if necessary.
384 
385   OperandType type = (OperandType)operand.type;
386 
387   bool isBranch = false;
388   uint64_t pcrel = 0;
389   if (type == TYPE_REL) {
390     isBranch = true;
391     pcrel = insn.startLocation +
392             insn.immediateOffset + insn.immediateSize;
393     switch (operand.encoding) {
394     default:
395       break;
396     case ENCODING_Iv:
397       switch (insn.displacementSize) {
398       default:
399         break;
400       case 1:
401         if(immediate & 0x80)
402           immediate |= ~(0xffull);
403         break;
404       case 2:
405         if(immediate & 0x8000)
406           immediate |= ~(0xffffull);
407         break;
408       case 4:
409         if(immediate & 0x80000000)
410           immediate |= ~(0xffffffffull);
411         break;
412       case 8:
413         break;
414       }
415       break;
416     case ENCODING_IB:
417       if(immediate & 0x80)
418         immediate |= ~(0xffull);
419       break;
420     case ENCODING_IW:
421       if(immediate & 0x8000)
422         immediate |= ~(0xffffull);
423       break;
424     case ENCODING_ID:
425       if(immediate & 0x80000000)
426         immediate |= ~(0xffffffffull);
427       break;
428     }
429   }
430   // By default sign-extend all X86 immediates based on their encoding.
431   else if (type == TYPE_IMM) {
432     switch (operand.encoding) {
433     default:
434       break;
435     case ENCODING_IB:
436       if(immediate & 0x80)
437         immediate |= ~(0xffull);
438       break;
439     case ENCODING_IW:
440       if(immediate & 0x8000)
441         immediate |= ~(0xffffull);
442       break;
443     case ENCODING_ID:
444       if(immediate & 0x80000000)
445         immediate |= ~(0xffffffffull);
446       break;
447     case ENCODING_IO:
448       break;
449     }
450   } else if (type == TYPE_IMM3) {
451     // Check for immediates that printSSECC can't handle.
452     if (immediate >= 8) {
453       unsigned NewOpc;
454       switch (mcInst.getOpcode()) {
455       default: llvm_unreachable("unexpected opcode");
456       case X86::CMPPDrmi:  NewOpc = X86::CMPPDrmi_alt;  break;
457       case X86::CMPPDrri:  NewOpc = X86::CMPPDrri_alt;  break;
458       case X86::CMPPSrmi:  NewOpc = X86::CMPPSrmi_alt;  break;
459       case X86::CMPPSrri:  NewOpc = X86::CMPPSrri_alt;  break;
460       case X86::CMPSDrm:   NewOpc = X86::CMPSDrm_alt;   break;
461       case X86::CMPSDrr:   NewOpc = X86::CMPSDrr_alt;   break;
462       case X86::CMPSSrm:   NewOpc = X86::CMPSSrm_alt;   break;
463       case X86::CMPSSrr:   NewOpc = X86::CMPSSrr_alt;   break;
464       case X86::VPCOMBri:  NewOpc = X86::VPCOMBri_alt;  break;
465       case X86::VPCOMBmi:  NewOpc = X86::VPCOMBmi_alt;  break;
466       case X86::VPCOMWri:  NewOpc = X86::VPCOMWri_alt;  break;
467       case X86::VPCOMWmi:  NewOpc = X86::VPCOMWmi_alt;  break;
468       case X86::VPCOMDri:  NewOpc = X86::VPCOMDri_alt;  break;
469       case X86::VPCOMDmi:  NewOpc = X86::VPCOMDmi_alt;  break;
470       case X86::VPCOMQri:  NewOpc = X86::VPCOMQri_alt;  break;
471       case X86::VPCOMQmi:  NewOpc = X86::VPCOMQmi_alt;  break;
472       case X86::VPCOMUBri: NewOpc = X86::VPCOMUBri_alt; break;
473       case X86::VPCOMUBmi: NewOpc = X86::VPCOMUBmi_alt; break;
474       case X86::VPCOMUWri: NewOpc = X86::VPCOMUWri_alt; break;
475       case X86::VPCOMUWmi: NewOpc = X86::VPCOMUWmi_alt; break;
476       case X86::VPCOMUDri: NewOpc = X86::VPCOMUDri_alt; break;
477       case X86::VPCOMUDmi: NewOpc = X86::VPCOMUDmi_alt; break;
478       case X86::VPCOMUQri: NewOpc = X86::VPCOMUQri_alt; break;
479       case X86::VPCOMUQmi: NewOpc = X86::VPCOMUQmi_alt; break;
480       }
481       // Switch opcode to the one that doesn't get special printing.
482       mcInst.setOpcode(NewOpc);
483     }
484   } else if (type == TYPE_IMM5) {
485     // Check for immediates that printAVXCC can't handle.
486     if (immediate >= 32) {
487       unsigned NewOpc;
488       switch (mcInst.getOpcode()) {
489       default: llvm_unreachable("unexpected opcode");
490       case X86::VCMPPDrmi:   NewOpc = X86::VCMPPDrmi_alt;   break;
491       case X86::VCMPPDrri:   NewOpc = X86::VCMPPDrri_alt;   break;
492       case X86::VCMPPSrmi:   NewOpc = X86::VCMPPSrmi_alt;   break;
493       case X86::VCMPPSrri:   NewOpc = X86::VCMPPSrri_alt;   break;
494       case X86::VCMPSDrm:    NewOpc = X86::VCMPSDrm_alt;    break;
495       case X86::VCMPSDrr:    NewOpc = X86::VCMPSDrr_alt;    break;
496       case X86::VCMPSSrm:    NewOpc = X86::VCMPSSrm_alt;    break;
497       case X86::VCMPSSrr:    NewOpc = X86::VCMPSSrr_alt;    break;
498       case X86::VCMPPDYrmi:  NewOpc = X86::VCMPPDYrmi_alt;  break;
499       case X86::VCMPPDYrri:  NewOpc = X86::VCMPPDYrri_alt;  break;
500       case X86::VCMPPSYrmi:  NewOpc = X86::VCMPPSYrmi_alt;  break;
501       case X86::VCMPPSYrri:  NewOpc = X86::VCMPPSYrri_alt;  break;
502       case X86::VCMPPDZrmi:  NewOpc = X86::VCMPPDZrmi_alt;  break;
503       case X86::VCMPPDZrri:  NewOpc = X86::VCMPPDZrri_alt;  break;
504       case X86::VCMPPDZrrib: NewOpc = X86::VCMPPDZrrib_alt; break;
505       case X86::VCMPPSZrmi:  NewOpc = X86::VCMPPSZrmi_alt;  break;
506       case X86::VCMPPSZrri:  NewOpc = X86::VCMPPSZrri_alt;  break;
507       case X86::VCMPPSZrrib: NewOpc = X86::VCMPPSZrrib_alt; break;
508       case X86::VCMPPDZ128rmi:  NewOpc = X86::VCMPPDZ128rmi_alt;  break;
509       case X86::VCMPPDZ128rri:  NewOpc = X86::VCMPPDZ128rri_alt;  break;
510       case X86::VCMPPSZ128rmi:  NewOpc = X86::VCMPPSZ128rmi_alt;  break;
511       case X86::VCMPPSZ128rri:  NewOpc = X86::VCMPPSZ128rri_alt;  break;
512       case X86::VCMPPDZ256rmi:  NewOpc = X86::VCMPPDZ256rmi_alt;  break;
513       case X86::VCMPPDZ256rri:  NewOpc = X86::VCMPPDZ256rri_alt;  break;
514       case X86::VCMPPSZ256rmi:  NewOpc = X86::VCMPPSZ256rmi_alt;  break;
515       case X86::VCMPPSZ256rri:  NewOpc = X86::VCMPPSZ256rri_alt;  break;
516       case X86::VCMPSDZrm_Int:  NewOpc = X86::VCMPSDZrmi_alt;  break;
517       case X86::VCMPSDZrr_Int:  NewOpc = X86::VCMPSDZrri_alt;  break;
518       case X86::VCMPSDZrrb_Int: NewOpc = X86::VCMPSDZrrb_alt;  break;
519       case X86::VCMPSSZrm_Int:  NewOpc = X86::VCMPSSZrmi_alt;  break;
520       case X86::VCMPSSZrr_Int:  NewOpc = X86::VCMPSSZrri_alt;  break;
521       case X86::VCMPSSZrrb_Int: NewOpc = X86::VCMPSSZrrb_alt;  break;
522       }
523       // Switch opcode to the one that doesn't get special printing.
524       mcInst.setOpcode(NewOpc);
525     }
526   } else if (type == TYPE_AVX512ICC) {
527     if (immediate >= 8 || ((immediate & 0x3) == 3)) {
528       unsigned NewOpc;
529       switch (mcInst.getOpcode()) {
530       default: llvm_unreachable("unexpected opcode");
531       case X86::VPCMPBZ128rmi:    NewOpc = X86::VPCMPBZ128rmi_alt;    break;
532       case X86::VPCMPBZ128rmik:   NewOpc = X86::VPCMPBZ128rmik_alt;   break;
533       case X86::VPCMPBZ128rri:    NewOpc = X86::VPCMPBZ128rri_alt;    break;
534       case X86::VPCMPBZ128rrik:   NewOpc = X86::VPCMPBZ128rrik_alt;   break;
535       case X86::VPCMPBZ256rmi:    NewOpc = X86::VPCMPBZ256rmi_alt;    break;
536       case X86::VPCMPBZ256rmik:   NewOpc = X86::VPCMPBZ256rmik_alt;   break;
537       case X86::VPCMPBZ256rri:    NewOpc = X86::VPCMPBZ256rri_alt;    break;
538       case X86::VPCMPBZ256rrik:   NewOpc = X86::VPCMPBZ256rrik_alt;   break;
539       case X86::VPCMPBZrmi:       NewOpc = X86::VPCMPBZrmi_alt;       break;
540       case X86::VPCMPBZrmik:      NewOpc = X86::VPCMPBZrmik_alt;      break;
541       case X86::VPCMPBZrri:       NewOpc = X86::VPCMPBZrri_alt;       break;
542       case X86::VPCMPBZrrik:      NewOpc = X86::VPCMPBZrrik_alt;      break;
543       case X86::VPCMPDZ128rmi:    NewOpc = X86::VPCMPDZ128rmi_alt;    break;
544       case X86::VPCMPDZ128rmib:   NewOpc = X86::VPCMPDZ128rmib_alt;   break;
545       case X86::VPCMPDZ128rmibk:  NewOpc = X86::VPCMPDZ128rmibk_alt;  break;
546       case X86::VPCMPDZ128rmik:   NewOpc = X86::VPCMPDZ128rmik_alt;   break;
547       case X86::VPCMPDZ128rri:    NewOpc = X86::VPCMPDZ128rri_alt;    break;
548       case X86::VPCMPDZ128rrik:   NewOpc = X86::VPCMPDZ128rrik_alt;   break;
549       case X86::VPCMPDZ256rmi:    NewOpc = X86::VPCMPDZ256rmi_alt;    break;
550       case X86::VPCMPDZ256rmib:   NewOpc = X86::VPCMPDZ256rmib_alt;   break;
551       case X86::VPCMPDZ256rmibk:  NewOpc = X86::VPCMPDZ256rmibk_alt;  break;
552       case X86::VPCMPDZ256rmik:   NewOpc = X86::VPCMPDZ256rmik_alt;   break;
553       case X86::VPCMPDZ256rri:    NewOpc = X86::VPCMPDZ256rri_alt;    break;
554       case X86::VPCMPDZ256rrik:   NewOpc = X86::VPCMPDZ256rrik_alt;   break;
555       case X86::VPCMPDZrmi:       NewOpc = X86::VPCMPDZrmi_alt;       break;
556       case X86::VPCMPDZrmib:      NewOpc = X86::VPCMPDZrmib_alt;      break;
557       case X86::VPCMPDZrmibk:     NewOpc = X86::VPCMPDZrmibk_alt;     break;
558       case X86::VPCMPDZrmik:      NewOpc = X86::VPCMPDZrmik_alt;      break;
559       case X86::VPCMPDZrri:       NewOpc = X86::VPCMPDZrri_alt;       break;
560       case X86::VPCMPDZrrik:      NewOpc = X86::VPCMPDZrrik_alt;      break;
561       case X86::VPCMPQZ128rmi:    NewOpc = X86::VPCMPQZ128rmi_alt;    break;
562       case X86::VPCMPQZ128rmib:   NewOpc = X86::VPCMPQZ128rmib_alt;   break;
563       case X86::VPCMPQZ128rmibk:  NewOpc = X86::VPCMPQZ128rmibk_alt;  break;
564       case X86::VPCMPQZ128rmik:   NewOpc = X86::VPCMPQZ128rmik_alt;   break;
565       case X86::VPCMPQZ128rri:    NewOpc = X86::VPCMPQZ128rri_alt;    break;
566       case X86::VPCMPQZ128rrik:   NewOpc = X86::VPCMPQZ128rrik_alt;   break;
567       case X86::VPCMPQZ256rmi:    NewOpc = X86::VPCMPQZ256rmi_alt;    break;
568       case X86::VPCMPQZ256rmib:   NewOpc = X86::VPCMPQZ256rmib_alt;   break;
569       case X86::VPCMPQZ256rmibk:  NewOpc = X86::VPCMPQZ256rmibk_alt;  break;
570       case X86::VPCMPQZ256rmik:   NewOpc = X86::VPCMPQZ256rmik_alt;   break;
571       case X86::VPCMPQZ256rri:    NewOpc = X86::VPCMPQZ256rri_alt;    break;
572       case X86::VPCMPQZ256rrik:   NewOpc = X86::VPCMPQZ256rrik_alt;   break;
573       case X86::VPCMPQZrmi:       NewOpc = X86::VPCMPQZrmi_alt;       break;
574       case X86::VPCMPQZrmib:      NewOpc = X86::VPCMPQZrmib_alt;      break;
575       case X86::VPCMPQZrmibk:     NewOpc = X86::VPCMPQZrmibk_alt;     break;
576       case X86::VPCMPQZrmik:      NewOpc = X86::VPCMPQZrmik_alt;      break;
577       case X86::VPCMPQZrri:       NewOpc = X86::VPCMPQZrri_alt;       break;
578       case X86::VPCMPQZrrik:      NewOpc = X86::VPCMPQZrrik_alt;      break;
579       case X86::VPCMPUBZ128rmi:   NewOpc = X86::VPCMPUBZ128rmi_alt;   break;
580       case X86::VPCMPUBZ128rmik:  NewOpc = X86::VPCMPUBZ128rmik_alt;  break;
581       case X86::VPCMPUBZ128rri:   NewOpc = X86::VPCMPUBZ128rri_alt;   break;
582       case X86::VPCMPUBZ128rrik:  NewOpc = X86::VPCMPUBZ128rrik_alt;  break;
583       case X86::VPCMPUBZ256rmi:   NewOpc = X86::VPCMPUBZ256rmi_alt;   break;
584       case X86::VPCMPUBZ256rmik:  NewOpc = X86::VPCMPUBZ256rmik_alt;  break;
585       case X86::VPCMPUBZ256rri:   NewOpc = X86::VPCMPUBZ256rri_alt;   break;
586       case X86::VPCMPUBZ256rrik:  NewOpc = X86::VPCMPUBZ256rrik_alt;  break;
587       case X86::VPCMPUBZrmi:      NewOpc = X86::VPCMPUBZrmi_alt;      break;
588       case X86::VPCMPUBZrmik:     NewOpc = X86::VPCMPUBZrmik_alt;     break;
589       case X86::VPCMPUBZrri:      NewOpc = X86::VPCMPUBZrri_alt;      break;
590       case X86::VPCMPUBZrrik:     NewOpc = X86::VPCMPUBZrrik_alt;     break;
591       case X86::VPCMPUDZ128rmi:   NewOpc = X86::VPCMPUDZ128rmi_alt;   break;
592       case X86::VPCMPUDZ128rmib:  NewOpc = X86::VPCMPUDZ128rmib_alt;  break;
593       case X86::VPCMPUDZ128rmibk: NewOpc = X86::VPCMPUDZ128rmibk_alt; break;
594       case X86::VPCMPUDZ128rmik:  NewOpc = X86::VPCMPUDZ128rmik_alt;  break;
595       case X86::VPCMPUDZ128rri:   NewOpc = X86::VPCMPUDZ128rri_alt;   break;
596       case X86::VPCMPUDZ128rrik:  NewOpc = X86::VPCMPUDZ128rrik_alt;  break;
597       case X86::VPCMPUDZ256rmi:   NewOpc = X86::VPCMPUDZ256rmi_alt;   break;
598       case X86::VPCMPUDZ256rmib:  NewOpc = X86::VPCMPUDZ256rmib_alt;  break;
599       case X86::VPCMPUDZ256rmibk: NewOpc = X86::VPCMPUDZ256rmibk_alt; break;
600       case X86::VPCMPUDZ256rmik:  NewOpc = X86::VPCMPUDZ256rmik_alt;  break;
601       case X86::VPCMPUDZ256rri:   NewOpc = X86::VPCMPUDZ256rri_alt;   break;
602       case X86::VPCMPUDZ256rrik:  NewOpc = X86::VPCMPUDZ256rrik_alt;  break;
603       case X86::VPCMPUDZrmi:      NewOpc = X86::VPCMPUDZrmi_alt;      break;
604       case X86::VPCMPUDZrmib:     NewOpc = X86::VPCMPUDZrmib_alt;     break;
605       case X86::VPCMPUDZrmibk:    NewOpc = X86::VPCMPUDZrmibk_alt;    break;
606       case X86::VPCMPUDZrmik:     NewOpc = X86::VPCMPUDZrmik_alt;     break;
607       case X86::VPCMPUDZrri:      NewOpc = X86::VPCMPUDZrri_alt;      break;
608       case X86::VPCMPUDZrrik:     NewOpc = X86::VPCMPUDZrrik_alt;     break;
609       case X86::VPCMPUQZ128rmi:   NewOpc = X86::VPCMPUQZ128rmi_alt;   break;
610       case X86::VPCMPUQZ128rmib:  NewOpc = X86::VPCMPUQZ128rmib_alt;  break;
611       case X86::VPCMPUQZ128rmibk: NewOpc = X86::VPCMPUQZ128rmibk_alt; break;
612       case X86::VPCMPUQZ128rmik:  NewOpc = X86::VPCMPUQZ128rmik_alt;  break;
613       case X86::VPCMPUQZ128rri:   NewOpc = X86::VPCMPUQZ128rri_alt;   break;
614       case X86::VPCMPUQZ128rrik:  NewOpc = X86::VPCMPUQZ128rrik_alt;  break;
615       case X86::VPCMPUQZ256rmi:   NewOpc = X86::VPCMPUQZ256rmi_alt;   break;
616       case X86::VPCMPUQZ256rmib:  NewOpc = X86::VPCMPUQZ256rmib_alt;  break;
617       case X86::VPCMPUQZ256rmibk: NewOpc = X86::VPCMPUQZ256rmibk_alt; break;
618       case X86::VPCMPUQZ256rmik:  NewOpc = X86::VPCMPUQZ256rmik_alt;  break;
619       case X86::VPCMPUQZ256rri:   NewOpc = X86::VPCMPUQZ256rri_alt;   break;
620       case X86::VPCMPUQZ256rrik:  NewOpc = X86::VPCMPUQZ256rrik_alt;  break;
621       case X86::VPCMPUQZrmi:      NewOpc = X86::VPCMPUQZrmi_alt;      break;
622       case X86::VPCMPUQZrmib:     NewOpc = X86::VPCMPUQZrmib_alt;     break;
623       case X86::VPCMPUQZrmibk:    NewOpc = X86::VPCMPUQZrmibk_alt;    break;
624       case X86::VPCMPUQZrmik:     NewOpc = X86::VPCMPUQZrmik_alt;     break;
625       case X86::VPCMPUQZrri:      NewOpc = X86::VPCMPUQZrri_alt;      break;
626       case X86::VPCMPUQZrrik:     NewOpc = X86::VPCMPUQZrrik_alt;     break;
627       case X86::VPCMPUWZ128rmi:   NewOpc = X86::VPCMPUWZ128rmi_alt;   break;
628       case X86::VPCMPUWZ128rmik:  NewOpc = X86::VPCMPUWZ128rmik_alt;  break;
629       case X86::VPCMPUWZ128rri:   NewOpc = X86::VPCMPUWZ128rri_alt;   break;
630       case X86::VPCMPUWZ128rrik:  NewOpc = X86::VPCMPUWZ128rrik_alt;  break;
631       case X86::VPCMPUWZ256rmi:   NewOpc = X86::VPCMPUWZ256rmi_alt;   break;
632       case X86::VPCMPUWZ256rmik:  NewOpc = X86::VPCMPUWZ256rmik_alt;  break;
633       case X86::VPCMPUWZ256rri:   NewOpc = X86::VPCMPUWZ256rri_alt;   break;
634       case X86::VPCMPUWZ256rrik:  NewOpc = X86::VPCMPUWZ256rrik_alt;  break;
635       case X86::VPCMPUWZrmi:      NewOpc = X86::VPCMPUWZrmi_alt;      break;
636       case X86::VPCMPUWZrmik:     NewOpc = X86::VPCMPUWZrmik_alt;     break;
637       case X86::VPCMPUWZrri:      NewOpc = X86::VPCMPUWZrri_alt;      break;
638       case X86::VPCMPUWZrrik:     NewOpc = X86::VPCMPUWZrrik_alt;     break;
639       case X86::VPCMPWZ128rmi:    NewOpc = X86::VPCMPWZ128rmi_alt;    break;
640       case X86::VPCMPWZ128rmik:   NewOpc = X86::VPCMPWZ128rmik_alt;   break;
641       case X86::VPCMPWZ128rri:    NewOpc = X86::VPCMPWZ128rri_alt;    break;
642       case X86::VPCMPWZ128rrik:   NewOpc = X86::VPCMPWZ128rrik_alt;   break;
643       case X86::VPCMPWZ256rmi:    NewOpc = X86::VPCMPWZ256rmi_alt;    break;
644       case X86::VPCMPWZ256rmik:   NewOpc = X86::VPCMPWZ256rmik_alt;   break;
645       case X86::VPCMPWZ256rri:    NewOpc = X86::VPCMPWZ256rri_alt;    break;
646       case X86::VPCMPWZ256rrik:   NewOpc = X86::VPCMPWZ256rrik_alt;   break;
647       case X86::VPCMPWZrmi:       NewOpc = X86::VPCMPWZrmi_alt;       break;
648       case X86::VPCMPWZrmik:      NewOpc = X86::VPCMPWZrmik_alt;      break;
649       case X86::VPCMPWZrri:       NewOpc = X86::VPCMPWZrri_alt;       break;
650       case X86::VPCMPWZrrik:      NewOpc = X86::VPCMPWZrrik_alt;      break;
651       }
652       // Switch opcode to the one that doesn't get special printing.
653       mcInst.setOpcode(NewOpc);
654     }
655   }
656 
657   switch (type) {
658   case TYPE_XMM:
659     mcInst.addOperand(MCOperand::createReg(X86::XMM0 + (immediate >> 4)));
660     return;
661   case TYPE_YMM:
662     mcInst.addOperand(MCOperand::createReg(X86::YMM0 + (immediate >> 4)));
663     return;
664   case TYPE_ZMM:
665     mcInst.addOperand(MCOperand::createReg(X86::ZMM0 + (immediate >> 4)));
666     return;
667   case TYPE_BNDR:
668     mcInst.addOperand(MCOperand::createReg(X86::BND0 + (immediate >> 4)));
669   default:
670     // operand is 64 bits wide.  Do nothing.
671     break;
672   }
673 
674   if(!tryAddingSymbolicOperand(immediate + pcrel, isBranch, insn.startLocation,
675                                insn.immediateOffset, insn.immediateSize,
676                                mcInst, Dis))
677     mcInst.addOperand(MCOperand::createImm(immediate));
678 
679   if (type == TYPE_MOFFS) {
680     MCOperand segmentReg;
681     segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]);
682     mcInst.addOperand(segmentReg);
683   }
684 }
685 
686 /// translateRMRegister - Translates a register stored in the R/M field of the
687 ///   ModR/M byte to its LLVM equivalent and appends it to an MCInst.
688 /// @param mcInst       - The MCInst to append to.
689 /// @param insn         - The internal instruction to extract the R/M field
690 ///                       from.
691 /// @return             - 0 on success; -1 otherwise
692 static bool translateRMRegister(MCInst &mcInst,
693                                 InternalInstruction &insn) {
694   if (insn.eaBase == EA_BASE_sib || insn.eaBase == EA_BASE_sib64) {
695     debug("A R/M register operand may not have a SIB byte");
696     return true;
697   }
698 
699   switch (insn.eaBase) {
700   default:
701     debug("Unexpected EA base register");
702     return true;
703   case EA_BASE_NONE:
704     debug("EA_BASE_NONE for ModR/M base");
705     return true;
706 #define ENTRY(x) case EA_BASE_##x:
707   ALL_EA_BASES
708 #undef ENTRY
709     debug("A R/M register operand may not have a base; "
710           "the operand must be a register.");
711     return true;
712 #define ENTRY(x)                                                      \
713   case EA_REG_##x:                                                    \
714     mcInst.addOperand(MCOperand::createReg(X86::x)); break;
715   ALL_REGS
716 #undef ENTRY
717   }
718 
719   return false;
720 }
721 
722 /// translateRMMemory - Translates a memory operand stored in the Mod and R/M
723 ///   fields of an internal instruction (and possibly its SIB byte) to a memory
724 ///   operand in LLVM's format, and appends it to an MCInst.
725 ///
726 /// @param mcInst       - The MCInst to append to.
727 /// @param insn         - The instruction to extract Mod, R/M, and SIB fields
728 ///                       from.
729 /// @return             - 0 on success; nonzero otherwise
730 static bool translateRMMemory(MCInst &mcInst, InternalInstruction &insn,
731                               const MCDisassembler *Dis) {
732   // Addresses in an MCInst are represented as five operands:
733   //   1. basereg       (register)  The R/M base, or (if there is a SIB) the
734   //                                SIB base
735   //   2. scaleamount   (immediate) 1, or (if there is a SIB) the specified
736   //                                scale amount
737   //   3. indexreg      (register)  x86_registerNONE, or (if there is a SIB)
738   //                                the index (which is multiplied by the
739   //                                scale amount)
740   //   4. displacement  (immediate) 0, or the displacement if there is one
741   //   5. segmentreg    (register)  x86_registerNONE for now, but could be set
742   //                                if we have segment overrides
743 
744   MCOperand baseReg;
745   MCOperand scaleAmount;
746   MCOperand indexReg;
747   MCOperand displacement;
748   MCOperand segmentReg;
749   uint64_t pcrel = 0;
750 
751   if (insn.eaBase == EA_BASE_sib || insn.eaBase == EA_BASE_sib64) {
752     if (insn.sibBase != SIB_BASE_NONE) {
753       switch (insn.sibBase) {
754       default:
755         debug("Unexpected sibBase");
756         return true;
757 #define ENTRY(x)                                          \
758       case SIB_BASE_##x:                                  \
759         baseReg = MCOperand::createReg(X86::x); break;
760       ALL_SIB_BASES
761 #undef ENTRY
762       }
763     } else {
764       baseReg = MCOperand::createReg(0);
765     }
766 
767     if (insn.sibIndex != SIB_INDEX_NONE) {
768       switch (insn.sibIndex) {
769       default:
770         debug("Unexpected sibIndex");
771         return true;
772 #define ENTRY(x)                                          \
773       case SIB_INDEX_##x:                                 \
774         indexReg = MCOperand::createReg(X86::x); break;
775       EA_BASES_32BIT
776       EA_BASES_64BIT
777       REGS_XMM
778       REGS_YMM
779       REGS_ZMM
780 #undef ENTRY
781       }
782     } else {
783       indexReg = MCOperand::createReg(0);
784     }
785 
786     scaleAmount = MCOperand::createImm(insn.sibScale);
787   } else {
788     switch (insn.eaBase) {
789     case EA_BASE_NONE:
790       if (insn.eaDisplacement == EA_DISP_NONE) {
791         debug("EA_BASE_NONE and EA_DISP_NONE for ModR/M base");
792         return true;
793       }
794       if (insn.mode == MODE_64BIT){
795         pcrel = insn.startLocation +
796                 insn.displacementOffset + insn.displacementSize;
797         tryAddingPcLoadReferenceComment(insn.startLocation +
798                                         insn.displacementOffset,
799                                         insn.displacement + pcrel, Dis);
800         baseReg = MCOperand::createReg(X86::RIP); // Section 2.2.1.6
801       }
802       else
803         baseReg = MCOperand::createReg(0);
804 
805       indexReg = MCOperand::createReg(0);
806       break;
807     case EA_BASE_BX_SI:
808       baseReg = MCOperand::createReg(X86::BX);
809       indexReg = MCOperand::createReg(X86::SI);
810       break;
811     case EA_BASE_BX_DI:
812       baseReg = MCOperand::createReg(X86::BX);
813       indexReg = MCOperand::createReg(X86::DI);
814       break;
815     case EA_BASE_BP_SI:
816       baseReg = MCOperand::createReg(X86::BP);
817       indexReg = MCOperand::createReg(X86::SI);
818       break;
819     case EA_BASE_BP_DI:
820       baseReg = MCOperand::createReg(X86::BP);
821       indexReg = MCOperand::createReg(X86::DI);
822       break;
823     default:
824       indexReg = MCOperand::createReg(0);
825       switch (insn.eaBase) {
826       default:
827         debug("Unexpected eaBase");
828         return true;
829         // Here, we will use the fill-ins defined above.  However,
830         //   BX_SI, BX_DI, BP_SI, and BP_DI are all handled above and
831         //   sib and sib64 were handled in the top-level if, so they're only
832         //   placeholders to keep the compiler happy.
833 #define ENTRY(x)                                        \
834       case EA_BASE_##x:                                 \
835         baseReg = MCOperand::createReg(X86::x); break;
836       ALL_EA_BASES
837 #undef ENTRY
838 #define ENTRY(x) case EA_REG_##x:
839       ALL_REGS
840 #undef ENTRY
841         debug("A R/M memory operand may not be a register; "
842               "the base field must be a base.");
843         return true;
844       }
845     }
846 
847     scaleAmount = MCOperand::createImm(1);
848   }
849 
850   displacement = MCOperand::createImm(insn.displacement);
851 
852   segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]);
853 
854   mcInst.addOperand(baseReg);
855   mcInst.addOperand(scaleAmount);
856   mcInst.addOperand(indexReg);
857   if(!tryAddingSymbolicOperand(insn.displacement + pcrel, false,
858                                insn.startLocation, insn.displacementOffset,
859                                insn.displacementSize, mcInst, Dis))
860     mcInst.addOperand(displacement);
861   mcInst.addOperand(segmentReg);
862   return false;
863 }
864 
865 /// translateRM - Translates an operand stored in the R/M (and possibly SIB)
866 ///   byte of an instruction to LLVM form, and appends it to an MCInst.
867 ///
868 /// @param mcInst       - The MCInst to append to.
869 /// @param operand      - The operand, as stored in the descriptor table.
870 /// @param insn         - The instruction to extract Mod, R/M, and SIB fields
871 ///                       from.
872 /// @return             - 0 on success; nonzero otherwise
873 static bool translateRM(MCInst &mcInst, const OperandSpecifier &operand,
874                         InternalInstruction &insn, const MCDisassembler *Dis) {
875   switch (operand.type) {
876   default:
877     debug("Unexpected type for a R/M operand");
878     return true;
879   case TYPE_R8:
880   case TYPE_R16:
881   case TYPE_R32:
882   case TYPE_R64:
883   case TYPE_Rv:
884   case TYPE_MM64:
885   case TYPE_XMM:
886   case TYPE_YMM:
887   case TYPE_ZMM:
888   case TYPE_VK:
889   case TYPE_DEBUGREG:
890   case TYPE_CONTROLREG:
891   case TYPE_BNDR:
892     return translateRMRegister(mcInst, insn);
893   case TYPE_M:
894   case TYPE_MVSIBX:
895   case TYPE_MVSIBY:
896   case TYPE_MVSIBZ:
897     return translateRMMemory(mcInst, insn, Dis);
898   }
899 }
900 
901 /// translateFPRegister - Translates a stack position on the FPU stack to its
902 ///   LLVM form, and appends it to an MCInst.
903 ///
904 /// @param mcInst       - The MCInst to append to.
905 /// @param stackPos     - The stack position to translate.
906 static void translateFPRegister(MCInst &mcInst,
907                                 uint8_t stackPos) {
908   mcInst.addOperand(MCOperand::createReg(X86::ST0 + stackPos));
909 }
910 
911 /// translateMaskRegister - Translates a 3-bit mask register number to
912 ///   LLVM form, and appends it to an MCInst.
913 ///
914 /// @param mcInst       - The MCInst to append to.
915 /// @param maskRegNum   - Number of mask register from 0 to 7.
916 /// @return             - false on success; true otherwise.
917 static bool translateMaskRegister(MCInst &mcInst,
918                                 uint8_t maskRegNum) {
919   if (maskRegNum >= 8) {
920     debug("Invalid mask register number");
921     return true;
922   }
923 
924   mcInst.addOperand(MCOperand::createReg(X86::K0 + maskRegNum));
925   return false;
926 }
927 
928 /// translateOperand - Translates an operand stored in an internal instruction
929 ///   to LLVM's format and appends it to an MCInst.
930 ///
931 /// @param mcInst       - The MCInst to append to.
932 /// @param operand      - The operand, as stored in the descriptor table.
933 /// @param insn         - The internal instruction.
934 /// @return             - false on success; true otherwise.
935 static bool translateOperand(MCInst &mcInst, const OperandSpecifier &operand,
936                              InternalInstruction &insn,
937                              const MCDisassembler *Dis) {
938   switch (operand.encoding) {
939   default:
940     debug("Unhandled operand encoding during translation");
941     return true;
942   case ENCODING_REG:
943     translateRegister(mcInst, insn.reg);
944     return false;
945   case ENCODING_WRITEMASK:
946     return translateMaskRegister(mcInst, insn.writemask);
947   CASE_ENCODING_RM:
948   CASE_ENCODING_VSIB:
949     return translateRM(mcInst, operand, insn, Dis);
950   case ENCODING_IB:
951   case ENCODING_IW:
952   case ENCODING_ID:
953   case ENCODING_IO:
954   case ENCODING_Iv:
955   case ENCODING_Ia:
956     translateImmediate(mcInst,
957                        insn.immediates[insn.numImmediatesTranslated++],
958                        operand,
959                        insn,
960                        Dis);
961     return false;
962   case ENCODING_IRC:
963     mcInst.addOperand(MCOperand::createImm(insn.RC));
964     return false;
965   case ENCODING_SI:
966     return translateSrcIndex(mcInst, insn);
967   case ENCODING_DI:
968     return translateDstIndex(mcInst, insn);
969   case ENCODING_RB:
970   case ENCODING_RW:
971   case ENCODING_RD:
972   case ENCODING_RO:
973   case ENCODING_Rv:
974     translateRegister(mcInst, insn.opcodeRegister);
975     return false;
976   case ENCODING_FP:
977     translateFPRegister(mcInst, insn.modRM & 7);
978     return false;
979   case ENCODING_VVVV:
980     translateRegister(mcInst, insn.vvvv);
981     return false;
982   case ENCODING_DUP:
983     return translateOperand(mcInst, insn.operands[operand.type - TYPE_DUP0],
984                             insn, Dis);
985   }
986 }
987 
988 /// translateInstruction - Translates an internal instruction and all its
989 ///   operands to an MCInst.
990 ///
991 /// @param mcInst       - The MCInst to populate with the instruction's data.
992 /// @param insn         - The internal instruction.
993 /// @return             - false on success; true otherwise.
994 static bool translateInstruction(MCInst &mcInst,
995                                 InternalInstruction &insn,
996                                 const MCDisassembler *Dis) {
997   if (!insn.spec) {
998     debug("Instruction has no specification");
999     return true;
1000   }
1001 
1002   mcInst.clear();
1003   mcInst.setOpcode(insn.instructionID);
1004   // If when reading the prefix bytes we determined the overlapping 0xf2 or 0xf3
1005   // prefix bytes should be disassembled as xrelease and xacquire then set the
1006   // opcode to those instead of the rep and repne opcodes.
1007   if (insn.xAcquireRelease) {
1008     if(mcInst.getOpcode() == X86::REP_PREFIX)
1009       mcInst.setOpcode(X86::XRELEASE_PREFIX);
1010     else if(mcInst.getOpcode() == X86::REPNE_PREFIX)
1011       mcInst.setOpcode(X86::XACQUIRE_PREFIX);
1012   }
1013 
1014   insn.numImmediatesTranslated = 0;
1015 
1016   for (const auto &Op : insn.operands) {
1017     if (Op.encoding != ENCODING_NONE) {
1018       if (translateOperand(mcInst, Op, insn, Dis)) {
1019         return true;
1020       }
1021     }
1022   }
1023 
1024   return false;
1025 }
1026 
1027 static MCDisassembler *createX86Disassembler(const Target &T,
1028                                              const MCSubtargetInfo &STI,
1029                                              MCContext &Ctx) {
1030   std::unique_ptr<const MCInstrInfo> MII(T.createMCInstrInfo());
1031   return new X86GenericDisassembler(STI, Ctx, std::move(MII));
1032 }
1033 
1034 extern "C" void LLVMInitializeX86Disassembler() {
1035   // Register the disassembler.
1036   TargetRegistry::RegisterMCDisassembler(getTheX86_32Target(),
1037                                          createX86Disassembler);
1038   TargetRegistry::RegisterMCDisassembler(getTheX86_64Target(),
1039                                          createX86Disassembler);
1040 }
1041