1 //===-- X86MCCodeEmitter.cpp - Convert X86 code to machine code -----------===//
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
7 //===----------------------------------------------------------------------===//
9 // This file implements the X86MCCodeEmitter class.
11 //===----------------------------------------------------------------------===//
13 #include "MCTargetDesc/X86BaseInfo.h"
14 #include "MCTargetDesc/X86FixupKinds.h"
15 #include "MCTargetDesc/X86MCTargetDesc.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/MC/MCCodeEmitter.h"
18 #include "llvm/MC/MCContext.h"
19 #include "llvm/MC/MCExpr.h"
20 #include "llvm/MC/MCFixup.h"
21 #include "llvm/MC/MCInst.h"
22 #include "llvm/MC/MCInstrDesc.h"
23 #include "llvm/MC/MCInstrInfo.h"
24 #include "llvm/MC/MCRegisterInfo.h"
25 #include "llvm/MC/MCSubtargetInfo.h"
26 #include "llvm/MC/MCSymbol.h"
27 #include "llvm/Support/ErrorHandling.h"
28 #include "llvm/Support/raw_ostream.h"
35 #define DEBUG_TYPE "mccodeemitter"
39 class X86MCCodeEmitter : public MCCodeEmitter {
40 const MCInstrInfo &MCII;
44 X86MCCodeEmitter(const MCInstrInfo &mcii, MCContext &ctx)
45 : MCII(mcii), Ctx(ctx) {}
46 X86MCCodeEmitter(const X86MCCodeEmitter &) = delete;
47 X86MCCodeEmitter &operator=(const X86MCCodeEmitter &) = delete;
48 ~X86MCCodeEmitter() override = default;
50 void emitPrefix(const MCInst &MI, raw_ostream &OS,
51 const MCSubtargetInfo &STI) const override;
53 void encodeInstruction(const MCInst &MI, raw_ostream &OS,
54 SmallVectorImpl<MCFixup> &Fixups,
55 const MCSubtargetInfo &STI) const override;
58 unsigned getX86RegNum(const MCOperand &MO) const {
59 return Ctx.getRegisterInfo()->getEncodingValue(MO.getReg()) & 0x7;
62 unsigned getX86RegEncoding(const MCInst &MI, unsigned OpNum) const {
63 return Ctx.getRegisterInfo()->getEncodingValue(
64 MI.getOperand(OpNum).getReg());
67 /// \param MI a single low-level machine instruction.
68 /// \param OpNum the operand #.
69 /// \returns true if the OpNumth operand of MI require a bit to be set in
71 bool isREXExtendedReg(const MCInst &MI, unsigned OpNum) const {
72 return (getX86RegEncoding(MI, OpNum) >> 3) & 1;
75 void emitByte(uint8_t C, unsigned &CurByte, raw_ostream &OS) const {
80 void emitConstant(uint64_t Val, unsigned Size, unsigned &CurByte,
81 raw_ostream &OS) const {
82 // Output the constant in little endian byte order.
83 for (unsigned i = 0; i != Size; ++i) {
84 emitByte(Val & 255, CurByte, OS);
89 void emitImmediate(const MCOperand &Disp, SMLoc Loc, unsigned ImmSize,
90 MCFixupKind FixupKind, unsigned &CurByte, raw_ostream &OS,
91 SmallVectorImpl<MCFixup> &Fixups, int ImmOffset = 0) const;
93 static uint8_t modRMByte(unsigned Mod, unsigned RegOpcode, unsigned RM) {
94 assert(Mod < 4 && RegOpcode < 8 && RM < 8 && "ModRM Fields out of range!");
95 return RM | (RegOpcode << 3) | (Mod << 6);
98 void emitRegModRMByte(const MCOperand &ModRMReg, unsigned RegOpcodeFld,
99 unsigned &CurByte, raw_ostream &OS) const {
100 emitByte(modRMByte(3, RegOpcodeFld, getX86RegNum(ModRMReg)), CurByte, OS);
103 void emitSIBByte(unsigned SS, unsigned Index, unsigned Base,
104 unsigned &CurByte, raw_ostream &OS) const {
105 // SIB byte is in the same format as the modRMByte.
106 emitByte(modRMByte(SS, Index, Base), CurByte, OS);
109 void emitMemModRMByte(const MCInst &MI, unsigned Op, unsigned RegOpcodeField,
110 uint64_t TSFlags, bool Rex, unsigned &CurByte,
111 raw_ostream &OS, SmallVectorImpl<MCFixup> &Fixups,
112 const MCSubtargetInfo &STI) const;
114 void emitPrefixImpl(uint64_t TSFlags, unsigned &CurOp, unsigned &CurByte,
115 bool &Rex, const MCInst &MI, const MCInstrDesc &Desc,
116 const MCSubtargetInfo &STI, raw_ostream &OS) const;
118 void emitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand,
119 const MCInst &MI, const MCInstrDesc &Desc,
120 raw_ostream &OS) const;
122 void emitSegmentOverridePrefix(unsigned &CurByte, unsigned SegOperand,
123 const MCInst &MI, raw_ostream &OS) const;
125 bool emitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand,
126 const MCInst &MI, const MCInstrDesc &Desc,
127 const MCSubtargetInfo &STI, raw_ostream &OS) const;
129 uint8_t determineREXPrefix(const MCInst &MI, uint64_t TSFlags, int MemOperand,
130 const MCInstrDesc &Desc) const;
133 } // end anonymous namespace
135 /// \returns true if this signed displacement fits in a 8-bit sign-extended
137 static bool isDisp8(int Value) { return Value == (int8_t)Value; }
139 /// \returns true if this signed displacement fits in a 8-bit compressed
140 /// dispacement field.
141 static bool isCDisp8(uint64_t TSFlags, int Value, int &CValue) {
142 assert(((TSFlags & X86II::EncodingMask) == X86II::EVEX) &&
143 "Compressed 8-bit displacement is only valid for EVEX inst.");
146 (TSFlags & X86II::CD8_Scale_Mask) >> X86II::CD8_Scale_Shift;
147 if (CD8_Scale == 0) {
149 return isDisp8(Value);
152 unsigned Mask = CD8_Scale - 1;
153 assert((CD8_Scale & Mask) == 0 && "Invalid memory object size.");
154 if (Value & Mask) // Unaligned offset
156 Value /= (int)CD8_Scale;
157 bool Ret = (Value == (int8_t)Value);
164 /// \returns the appropriate fixup kind to use for an immediate in an
165 /// instruction with the specified TSFlags.
166 static MCFixupKind getImmFixupKind(uint64_t TSFlags) {
167 unsigned Size = X86II::getSizeOfImm(TSFlags);
168 bool isPCRel = X86II::isImmPCRel(TSFlags);
170 if (X86II::isImmSigned(TSFlags)) {
173 llvm_unreachable("Unsupported signed fixup size!");
175 return MCFixupKind(X86::reloc_signed_4byte);
178 return MCFixup::getKindForSize(Size, isPCRel);
181 /// \param Op operand # of the memory operand.
183 /// \returns true if the specified instruction has a 16-bit memory operand.
184 static bool is16BitMemOperand(const MCInst &MI, unsigned Op,
185 const MCSubtargetInfo &STI) {
186 const MCOperand &BaseReg = MI.getOperand(Op + X86::AddrBaseReg);
187 const MCOperand &IndexReg = MI.getOperand(Op + X86::AddrIndexReg);
188 const MCOperand &Disp = MI.getOperand(Op + X86::AddrDisp);
190 if (STI.hasFeature(X86::Mode16Bit) && BaseReg.getReg() == 0 && Disp.isImm() &&
191 Disp.getImm() < 0x10000)
193 if ((BaseReg.getReg() != 0 &&
194 X86MCRegisterClasses[X86::GR16RegClassID].contains(BaseReg.getReg())) ||
195 (IndexReg.getReg() != 0 &&
196 X86MCRegisterClasses[X86::GR16RegClassID].contains(IndexReg.getReg())))
201 /// \param Op operand # of the memory operand.
203 /// \returns true if the specified instruction has a 32-bit memory operand.
204 static bool is32BitMemOperand(const MCInst &MI, unsigned Op) {
205 const MCOperand &BaseReg = MI.getOperand(Op + X86::AddrBaseReg);
206 const MCOperand &IndexReg = MI.getOperand(Op + X86::AddrIndexReg);
208 if ((BaseReg.getReg() != 0 &&
209 X86MCRegisterClasses[X86::GR32RegClassID].contains(BaseReg.getReg())) ||
210 (IndexReg.getReg() != 0 &&
211 X86MCRegisterClasses[X86::GR32RegClassID].contains(IndexReg.getReg())))
213 if (BaseReg.getReg() == X86::EIP) {
214 assert(IndexReg.getReg() == 0 && "Invalid eip-based address.");
217 if (IndexReg.getReg() == X86::EIZ)
222 /// \param Op operand # of the memory operand.
224 /// \returns true if the specified instruction has a 64-bit memory operand.
226 static bool is64BitMemOperand(const MCInst &MI, unsigned Op) {
227 const MCOperand &BaseReg = MI.getOperand(Op + X86::AddrBaseReg);
228 const MCOperand &IndexReg = MI.getOperand(Op + X86::AddrIndexReg);
230 if ((BaseReg.getReg() != 0 &&
231 X86MCRegisterClasses[X86::GR64RegClassID].contains(BaseReg.getReg())) ||
232 (IndexReg.getReg() != 0 &&
233 X86MCRegisterClasses[X86::GR64RegClassID].contains(IndexReg.getReg())))
239 enum GlobalOffsetTableExprKind { GOT_None, GOT_Normal, GOT_SymDiff };
241 /// Check if this expression starts with _GLOBAL_OFFSET_TABLE_ and if it is
242 /// of the form _GLOBAL_OFFSET_TABLE_-symbol. This is needed to support PIC on
243 /// ELF i386 as _GLOBAL_OFFSET_TABLE_ is magical. We check only simple case that
244 /// are know to be used: _GLOBAL_OFFSET_TABLE_ by itself or at the start of a
245 /// binary expression.
246 static GlobalOffsetTableExprKind
247 startsWithGlobalOffsetTable(const MCExpr *Expr) {
248 const MCExpr *RHS = nullptr;
249 if (Expr->getKind() == MCExpr::Binary) {
250 const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(Expr);
255 if (Expr->getKind() != MCExpr::SymbolRef)
258 const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr *>(Expr);
259 const MCSymbol &S = Ref->getSymbol();
260 if (S.getName() != "_GLOBAL_OFFSET_TABLE_")
262 if (RHS && RHS->getKind() == MCExpr::SymbolRef)
267 static bool hasSecRelSymbolRef(const MCExpr *Expr) {
268 if (Expr->getKind() == MCExpr::SymbolRef) {
269 const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr *>(Expr);
270 return Ref->getKind() == MCSymbolRefExpr::VK_SECREL;
275 static bool isPCRel32Branch(const MCInst &MI, const MCInstrInfo &MCII) {
276 unsigned Opcode = MI.getOpcode();
277 const MCInstrDesc &Desc = MCII.get(Opcode);
278 if ((Opcode != X86::CALL64pcrel32 && Opcode != X86::JMP_4) ||
279 getImmFixupKind(Desc.TSFlags) != FK_PCRel_4)
282 unsigned CurOp = X86II::getOperandBias(Desc);
283 const MCOperand &Op = MI.getOperand(CurOp);
287 const MCSymbolRefExpr *Ref = dyn_cast<MCSymbolRefExpr>(Op.getExpr());
288 return Ref && Ref->getKind() == MCSymbolRefExpr::VK_None;
291 void X86MCCodeEmitter::emitImmediate(const MCOperand &DispOp, SMLoc Loc,
292 unsigned Size, MCFixupKind FixupKind,
293 unsigned &CurByte, raw_ostream &OS,
294 SmallVectorImpl<MCFixup> &Fixups,
295 int ImmOffset) const {
296 const MCExpr *Expr = nullptr;
297 if (DispOp.isImm()) {
298 // If this is a simple integer displacement that doesn't require a
299 // relocation, emit it now.
300 if (FixupKind != FK_PCRel_1 && FixupKind != FK_PCRel_2 &&
301 FixupKind != FK_PCRel_4) {
302 emitConstant(DispOp.getImm() + ImmOffset, Size, CurByte, OS);
305 Expr = MCConstantExpr::create(DispOp.getImm(), Ctx);
307 Expr = DispOp.getExpr();
310 // If we have an immoffset, add it to the expression.
311 if ((FixupKind == FK_Data_4 || FixupKind == FK_Data_8 ||
312 FixupKind == MCFixupKind(X86::reloc_signed_4byte))) {
313 GlobalOffsetTableExprKind Kind = startsWithGlobalOffsetTable(Expr);
314 if (Kind != GOT_None) {
315 assert(ImmOffset == 0);
318 FixupKind = MCFixupKind(X86::reloc_global_offset_table8);
321 FixupKind = MCFixupKind(X86::reloc_global_offset_table);
324 if (Kind == GOT_Normal)
326 } else if (Expr->getKind() == MCExpr::SymbolRef) {
327 if (hasSecRelSymbolRef(Expr)) {
328 FixupKind = MCFixupKind(FK_SecRel_4);
330 } else if (Expr->getKind() == MCExpr::Binary) {
331 const MCBinaryExpr *Bin = static_cast<const MCBinaryExpr *>(Expr);
332 if (hasSecRelSymbolRef(Bin->getLHS()) ||
333 hasSecRelSymbolRef(Bin->getRHS())) {
334 FixupKind = MCFixupKind(FK_SecRel_4);
339 // If the fixup is pc-relative, we need to bias the value to be relative to
340 // the start of the field, not the end of the field.
341 if (FixupKind == FK_PCRel_4 ||
342 FixupKind == MCFixupKind(X86::reloc_riprel_4byte) ||
343 FixupKind == MCFixupKind(X86::reloc_riprel_4byte_movq_load) ||
344 FixupKind == MCFixupKind(X86::reloc_riprel_4byte_relax) ||
345 FixupKind == MCFixupKind(X86::reloc_riprel_4byte_relax_rex) ||
346 FixupKind == MCFixupKind(X86::reloc_branch_4byte_pcrel)) {
348 // If this is a pc-relative load off _GLOBAL_OFFSET_TABLE_:
349 // leaq _GLOBAL_OFFSET_TABLE_(%rip), %r15
350 // this needs to be a GOTPC32 relocation.
351 if (startsWithGlobalOffsetTable(Expr) != GOT_None)
352 FixupKind = MCFixupKind(X86::reloc_global_offset_table);
354 if (FixupKind == FK_PCRel_2)
356 if (FixupKind == FK_PCRel_1)
360 Expr = MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(ImmOffset, Ctx),
363 // Emit a symbolic constant as a fixup and 4 zeros.
364 Fixups.push_back(MCFixup::create(CurByte, Expr, FixupKind, Loc));
365 emitConstant(0, Size, CurByte, OS);
368 void X86MCCodeEmitter::emitMemModRMByte(const MCInst &MI, unsigned Op,
369 unsigned RegOpcodeField,
370 uint64_t TSFlags, bool Rex,
371 unsigned &CurByte, raw_ostream &OS,
372 SmallVectorImpl<MCFixup> &Fixups,
373 const MCSubtargetInfo &STI) const {
374 const MCOperand &Disp = MI.getOperand(Op + X86::AddrDisp);
375 const MCOperand &Base = MI.getOperand(Op + X86::AddrBaseReg);
376 const MCOperand &Scale = MI.getOperand(Op + X86::AddrScaleAmt);
377 const MCOperand &IndexReg = MI.getOperand(Op + X86::AddrIndexReg);
378 unsigned BaseReg = Base.getReg();
379 bool HasEVEX = (TSFlags & X86II::EncodingMask) == X86II::EVEX;
381 // Handle %rip relative addressing.
382 if (BaseReg == X86::RIP ||
383 BaseReg == X86::EIP) { // [disp32+rIP] in X86-64 mode
384 assert(STI.hasFeature(X86::Mode64Bit) &&
385 "Rip-relative addressing requires 64-bit mode");
386 assert(IndexReg.getReg() == 0 && "Invalid rip-relative address");
387 emitByte(modRMByte(0, RegOpcodeField, 5), CurByte, OS);
389 unsigned Opcode = MI.getOpcode();
390 // movq loads are handled with a special relocation form which allows the
391 // linker to eliminate some loads for GOT references which end up in the
392 // same linkage unit.
393 unsigned FixupKind = [=]() {
396 return X86::reloc_riprel_4byte;
399 return X86::reloc_riprel_4byte_movq_load;
402 case X86::TAILJMPm64:
412 return Rex ? X86::reloc_riprel_4byte_relax_rex
413 : X86::reloc_riprel_4byte_relax;
417 // rip-relative addressing is actually relative to the *next* instruction.
418 // Since an immediate can follow the mod/rm byte for an instruction, this
419 // means that we need to bias the displacement field of the instruction with
420 // the size of the immediate field. If we have this case, add it into the
421 // expression to emit.
422 // Note: rip-relative addressing using immediate displacement values should
423 // not be adjusted, assuming it was the user's intent.
424 int ImmSize = !Disp.isImm() && X86II::hasImm(TSFlags)
425 ? X86II::getSizeOfImm(TSFlags)
428 emitImmediate(Disp, MI.getLoc(), 4, MCFixupKind(FixupKind), CurByte, OS,
433 unsigned BaseRegNo = BaseReg ? getX86RegNum(Base) : -1U;
435 // 16-bit addressing forms of the ModR/M byte have a different encoding for
436 // the R/M field and are far more limited in which registers can be used.
437 if (is16BitMemOperand(MI, Op, STI)) {
439 // For 32-bit addressing, the row and column values in Table 2-2 are
440 // basically the same. It's AX/CX/DX/BX/SP/BP/SI/DI in that order, with
441 // some special cases. And getX86RegNum reflects that numbering.
442 // For 16-bit addressing it's more fun, as shown in the SDM Vol 2A,
443 // Table 2-1 "16-Bit Addressing Forms with the ModR/M byte". We can only
444 // use SI/DI/BP/BX, which have "row" values 4-7 in no particular order,
445 // while values 0-3 indicate the allowed combinations (base+index) of
446 // those: 0 for BX+SI, 1 for BX+DI, 2 for BP+SI, 3 for BP+DI.
448 // R16Table[] is a lookup from the normal RegNo, to the row values from
449 // Table 2-1 for 16-bit addressing modes. Where zero means disallowed.
450 static const unsigned R16Table[] = {0, 0, 0, 7, 0, 6, 4, 5};
451 unsigned RMfield = R16Table[BaseRegNo];
453 assert(RMfield && "invalid 16-bit base register");
455 if (IndexReg.getReg()) {
456 unsigned IndexReg16 = R16Table[getX86RegNum(IndexReg)];
458 assert(IndexReg16 && "invalid 16-bit index register");
459 // We must have one of SI/DI (4,5), and one of BP/BX (6,7).
460 assert(((IndexReg16 ^ RMfield) & 2) &&
461 "invalid 16-bit base/index register combination");
462 assert(Scale.getImm() == 1 &&
463 "invalid scale for 16-bit memory reference");
465 // Allow base/index to appear in either order (although GAS doesn't).
467 RMfield = (RMfield & 1) | ((7 - IndexReg16) << 1);
469 RMfield = (IndexReg16 & 1) | ((7 - RMfield) << 1);
472 if (Disp.isImm() && isDisp8(Disp.getImm())) {
473 if (Disp.getImm() == 0 && RMfield != 6) {
474 // There is no displacement; just the register.
475 emitByte(modRMByte(0, RegOpcodeField, RMfield), CurByte, OS);
478 // Use the [REG]+disp8 form, including for [BP] which cannot be encoded.
479 emitByte(modRMByte(1, RegOpcodeField, RMfield), CurByte, OS);
480 emitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups);
483 // This is the [REG]+disp16 case.
484 emitByte(modRMByte(2, RegOpcodeField, RMfield), CurByte, OS);
486 // There is no BaseReg; this is the plain [disp16] case.
487 emitByte(modRMByte(0, RegOpcodeField, 6), CurByte, OS);
490 // Emit 16-bit displacement for plain disp16 or [REG]+disp16 cases.
491 emitImmediate(Disp, MI.getLoc(), 2, FK_Data_2, CurByte, OS, Fixups);
495 // Determine whether a SIB byte is needed.
496 // If no BaseReg, issue a RIP relative instruction only if the MCE can
497 // resolve addresses on-the-fly, otherwise use SIB (Intel Manual 2A, table
498 // 2-7) and absolute references.
500 if ( // The SIB byte must be used if there is an index register.
501 IndexReg.getReg() == 0 &&
502 // The SIB byte must be used if the base is ESP/RSP/R12, all of which
503 // encode to an R/M value of 4, which indicates that a SIB byte is
505 BaseRegNo != N86::ESP &&
506 // If there is no base register and we're in 64-bit mode, we need a SIB
507 // byte to emit an addr that is just 'disp32' (the non-RIP relative form).
508 (!STI.hasFeature(X86::Mode64Bit) || BaseReg != 0)) {
510 if (BaseReg == 0) { // [disp32] in X86-32 mode
511 emitByte(modRMByte(0, RegOpcodeField, 5), CurByte, OS);
512 emitImmediate(Disp, MI.getLoc(), 4, FK_Data_4, CurByte, OS, Fixups);
516 // If the base is not EBP/ESP and there is no displacement, use simple
517 // indirect register encoding, this handles addresses like [EAX]. The
518 // encoding for [EBP] with no displacement means [disp32] so we handle it
519 // by emitting a displacement of 0 below.
520 if (BaseRegNo != N86::EBP) {
521 if (Disp.isImm() && Disp.getImm() == 0) {
522 emitByte(modRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS);
526 // If the displacement is @tlscall, treat it as a zero.
528 auto *Sym = dyn_cast<MCSymbolRefExpr>(Disp.getExpr());
529 if (Sym && Sym->getKind() == MCSymbolRefExpr::VK_TLSCALL) {
530 // This is exclusively used by call *a@tlscall(base). The relocation
531 // (R_386_TLSCALL or R_X86_64_TLSCALL) applies to the beginning.
532 Fixups.push_back(MCFixup::create(0, Sym, FK_NONE, MI.getLoc()));
533 emitByte(modRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS);
539 // Otherwise, if the displacement fits in a byte, encode as [REG+disp8].
541 if (!HasEVEX && isDisp8(Disp.getImm())) {
542 emitByte(modRMByte(1, RegOpcodeField, BaseRegNo), CurByte, OS);
543 emitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups);
546 // Try EVEX compressed 8-bit displacement first; if failed, fall back to
547 // 32-bit displacement.
549 if (HasEVEX && isCDisp8(TSFlags, Disp.getImm(), CDisp8)) {
550 emitByte(modRMByte(1, RegOpcodeField, BaseRegNo), CurByte, OS);
551 emitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups,
552 CDisp8 - Disp.getImm());
557 // Otherwise, emit the most general non-SIB encoding: [REG+disp32]
558 emitByte(modRMByte(2, RegOpcodeField, BaseRegNo), CurByte, OS);
559 unsigned Opcode = MI.getOpcode();
560 unsigned FixupKind = Opcode == X86::MOV32rm ? X86::reloc_signed_4byte_relax
561 : X86::reloc_signed_4byte;
562 emitImmediate(Disp, MI.getLoc(), 4, MCFixupKind(FixupKind), CurByte, OS,
567 // We need a SIB byte, so start by outputting the ModR/M byte first
568 assert(IndexReg.getReg() != X86::ESP && IndexReg.getReg() != X86::RSP &&
569 "Cannot use ESP as index reg!");
571 bool ForceDisp32 = false;
572 bool ForceDisp8 = false;
576 // If there is no base register, we emit the special case SIB byte with
577 // MOD=0, BASE=5, to JUST get the index, scale, and displacement.
578 emitByte(modRMByte(0, RegOpcodeField, 4), CurByte, OS);
580 } else if (!Disp.isImm()) {
581 // Emit the normal disp32 encoding.
582 emitByte(modRMByte(2, RegOpcodeField, 4), CurByte, OS);
584 } else if (Disp.getImm() == 0 &&
585 // Base reg can't be anything that ends up with '5' as the base
586 // reg, it is the magic [*] nomenclature that indicates no base.
587 BaseRegNo != N86::EBP) {
588 // Emit no displacement ModR/M byte
589 emitByte(modRMByte(0, RegOpcodeField, 4), CurByte, OS);
590 } else if (!HasEVEX && isDisp8(Disp.getImm())) {
591 // Emit the disp8 encoding.
592 emitByte(modRMByte(1, RegOpcodeField, 4), CurByte, OS);
593 ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
594 } else if (HasEVEX && isCDisp8(TSFlags, Disp.getImm(), CDisp8)) {
595 // Emit the disp8 encoding.
596 emitByte(modRMByte(1, RegOpcodeField, 4), CurByte, OS);
597 ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
598 ImmOffset = CDisp8 - Disp.getImm();
600 // Emit the normal disp32 encoding.
601 emitByte(modRMByte(2, RegOpcodeField, 4), CurByte, OS);
604 // Calculate what the SS field value should be...
605 static const unsigned SSTable[] = {~0U, 0, 1, ~0U, 2, ~0U, ~0U, ~0U, 3};
606 unsigned SS = SSTable[Scale.getImm()];
609 // Handle the SIB byte for the case where there is no base, see Intel
610 // Manual 2A, table 2-7. The displacement has already been output.
612 if (IndexReg.getReg())
613 IndexRegNo = getX86RegNum(IndexReg);
614 else // Examples: [ESP+1*<noreg>+4] or [scaled idx]+disp32 (MOD=0,BASE=5)
616 emitSIBByte(SS, IndexRegNo, 5, CurByte, OS);
619 if (IndexReg.getReg())
620 IndexRegNo = getX86RegNum(IndexReg);
622 IndexRegNo = 4; // For example [ESP+1*<noreg>+4]
623 emitSIBByte(SS, IndexRegNo, getX86RegNum(Base), CurByte, OS);
626 // Do we need to output a displacement?
628 emitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups,
630 else if (ForceDisp32 || Disp.getImm() != 0)
631 emitImmediate(Disp, MI.getLoc(), 4, MCFixupKind(X86::reloc_signed_4byte),
632 CurByte, OS, Fixups);
635 void X86MCCodeEmitter::emitPrefixImpl(uint64_t TSFlags, unsigned &CurOp,
636 unsigned &CurByte, bool &Rex,
637 const MCInst &MI, const MCInstrDesc &Desc,
638 const MCSubtargetInfo &STI,
639 raw_ostream &OS) const {
640 // Determine where the memory operand starts, if present.
641 int MemoryOperand = X86II::getMemoryOperandNo(TSFlags);
642 if (MemoryOperand != -1)
643 MemoryOperand += CurOp;
645 // Emit segment override opcode prefix as needed.
646 if (MemoryOperand >= 0)
647 emitSegmentOverridePrefix(CurByte, MemoryOperand + X86::AddrSegmentReg, MI,
650 // Emit the repeat opcode prefix as needed.
651 unsigned Flags = MI.getFlags();
652 if (TSFlags & X86II::REP || Flags & X86::IP_HAS_REPEAT)
653 emitByte(0xF3, CurByte, OS);
654 if (Flags & X86::IP_HAS_REPEAT_NE)
655 emitByte(0xF2, CurByte, OS);
657 // Emit the address size opcode prefix as needed.
658 bool need_address_override;
659 uint64_t AdSize = TSFlags & X86II::AdSizeMask;
660 if ((STI.hasFeature(X86::Mode16Bit) && AdSize == X86II::AdSize32) ||
661 (STI.hasFeature(X86::Mode32Bit) && AdSize == X86II::AdSize16) ||
662 (STI.hasFeature(X86::Mode64Bit) && AdSize == X86II::AdSize32)) {
663 need_address_override = true;
664 } else if (MemoryOperand < 0) {
665 need_address_override = false;
666 } else if (STI.hasFeature(X86::Mode64Bit)) {
667 assert(!is16BitMemOperand(MI, MemoryOperand, STI));
668 need_address_override = is32BitMemOperand(MI, MemoryOperand);
669 } else if (STI.hasFeature(X86::Mode32Bit)) {
670 assert(!is64BitMemOperand(MI, MemoryOperand));
671 need_address_override = is16BitMemOperand(MI, MemoryOperand, STI);
673 assert(STI.hasFeature(X86::Mode16Bit));
674 assert(!is64BitMemOperand(MI, MemoryOperand));
675 need_address_override = !is16BitMemOperand(MI, MemoryOperand, STI);
678 if (need_address_override)
679 emitByte(0x67, CurByte, OS);
681 // Encoding type for this instruction.
682 uint64_t Encoding = TSFlags & X86II::EncodingMask;
684 Rex = emitOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, STI, OS);
686 emitVEXOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, OS);
688 uint64_t Form = TSFlags & X86II::FormMask;
692 case X86II::RawFrmDstSrc: {
693 unsigned siReg = MI.getOperand(1).getReg();
694 assert(((siReg == X86::SI && MI.getOperand(0).getReg() == X86::DI) ||
695 (siReg == X86::ESI && MI.getOperand(0).getReg() == X86::EDI) ||
696 (siReg == X86::RSI && MI.getOperand(0).getReg() == X86::RDI)) &&
697 "SI and DI register sizes do not match");
698 // Emit segment override opcode prefix as needed (not for %ds).
699 if (MI.getOperand(2).getReg() != X86::DS)
700 emitSegmentOverridePrefix(CurByte, 2, MI, OS);
701 // Emit AdSize prefix as needed.
702 if ((!STI.hasFeature(X86::Mode32Bit) && siReg == X86::ESI) ||
703 (STI.hasFeature(X86::Mode32Bit) && siReg == X86::SI))
704 emitByte(0x67, CurByte, OS);
705 CurOp += 3; // Consume operands.
708 case X86II::RawFrmSrc: {
709 unsigned siReg = MI.getOperand(0).getReg();
710 // Emit segment override opcode prefix as needed (not for %ds).
711 if (MI.getOperand(1).getReg() != X86::DS)
712 emitSegmentOverridePrefix(CurByte, 1, MI, OS);
713 // Emit AdSize prefix as needed.
714 if ((!STI.hasFeature(X86::Mode32Bit) && siReg == X86::ESI) ||
715 (STI.hasFeature(X86::Mode32Bit) && siReg == X86::SI))
716 emitByte(0x67, CurByte, OS);
717 CurOp += 2; // Consume operands.
720 case X86II::RawFrmDst: {
721 unsigned siReg = MI.getOperand(0).getReg();
722 // Emit AdSize prefix as needed.
723 if ((!STI.hasFeature(X86::Mode32Bit) && siReg == X86::EDI) ||
724 (STI.hasFeature(X86::Mode32Bit) && siReg == X86::DI))
725 emitByte(0x67, CurByte, OS);
726 ++CurOp; // Consume operand.
729 case X86II::RawFrmMemOffs: {
730 // Emit segment override opcode prefix as needed.
731 emitSegmentOverridePrefix(CurByte, 1, MI, OS);
737 /// emitVEXOpcodePrefix - AVX instructions are encoded using a opcode prefix
739 void X86MCCodeEmitter::emitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
740 int MemOperand, const MCInst &MI,
741 const MCInstrDesc &Desc,
742 raw_ostream &OS) const {
743 assert(!(TSFlags & X86II::LOCK) && "Can't have LOCK VEX.");
745 uint64_t Encoding = TSFlags & X86II::EncodingMask;
746 bool HasEVEX_K = TSFlags & X86II::EVEX_K;
747 bool HasVEX_4V = TSFlags & X86II::VEX_4V;
748 bool HasEVEX_RC = TSFlags & X86II::EVEX_RC;
750 // VEX_R: opcode externsion equivalent to REX.R in
751 // 1's complement (inverted) form
753 // 1: Same as REX_R=0 (must be 1 in 32-bit mode)
754 // 0: Same as REX_R=1 (64 bit mode only)
757 uint8_t EVEX_R2 = 0x1;
759 // VEX_X: equivalent to REX.X, only used when a
760 // register is used for index in SIB Byte.
762 // 1: Same as REX.X=0 (must be 1 in 32-bit mode)
763 // 0: Same as REX.X=1 (64-bit mode only)
768 // 1: Same as REX_B=0 (ignored in 32-bit mode)
769 // 0: Same as REX_B=1 (64 bit mode only)
773 // VEX_W: opcode specific (use like REX.W, or used for
774 // opcode extension, or ignored, depending on the opcode byte)
775 uint8_t VEX_W = (TSFlags & X86II::VEX_W) ? 1 : 0;
777 // VEX_5M (VEX m-mmmmm field):
779 // 0b00000: Reserved for future use
780 // 0b00001: implied 0F leading opcode
781 // 0b00010: implied 0F 38 leading opcode bytes
782 // 0b00011: implied 0F 3A leading opcode bytes
783 // 0b00100-0b11111: Reserved for future use
784 // 0b01000: XOP map select - 08h instructions with imm byte
785 // 0b01001: XOP map select - 09h instructions with no imm byte
786 // 0b01010: XOP map select - 0Ah instructions with imm dword
788 switch (TSFlags & X86II::OpMapMask) {
790 llvm_unreachable("Invalid prefix!");
811 // VEX_4V (VEX vvvv field): a register specifier
812 // (in 1's complement form) or 1111 if unused.
813 uint8_t VEX_4V = 0xf;
814 uint8_t EVEX_V2 = 0x1;
816 // EVEX_L2/VEX_L (Vector Length):
819 // 0 0: scalar or 128-bit vector
820 // 0 1: 256-bit vector
821 // 1 0: 512-bit vector
823 uint8_t VEX_L = (TSFlags & X86II::VEX_L) ? 1 : 0;
824 uint8_t EVEX_L2 = (TSFlags & X86II::EVEX_L2) ? 1 : 0;
826 // VEX_PP: opcode extension providing equivalent
827 // functionality of a SIMD prefix
835 switch (TSFlags & X86II::OpPrefixMask) {
848 uint8_t EVEX_U = 1; // Always '1' so far
851 uint8_t EVEX_z = (HasEVEX_K && (TSFlags & X86II::EVEX_Z)) ? 1 : 0;
854 uint8_t EVEX_b = (TSFlags & X86II::EVEX_B) ? 1 : 0;
860 uint8_t EVEX_aaa = 0;
862 bool EncodeRC = false;
864 // Classify VEX_B, VEX_4V, VEX_R, VEX_X
865 unsigned NumOps = Desc.getNumOperands();
866 unsigned CurOp = X86II::getOperandBias(Desc);
868 switch (TSFlags & X86II::FormMask) {
870 llvm_unreachable("Unexpected form in emitVEXOpcodePrefix!");
873 case X86II::MRMDestMem: {
874 // MRMDestMem instructions forms:
875 // MemAddr, src1(ModR/M)
876 // MemAddr, src1(VEX_4V), src2(ModR/M)
877 // MemAddr, src1(ModR/M), imm8
879 unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg);
880 VEX_B = ~(BaseRegEnc >> 3) & 1;
881 unsigned IndexRegEnc =
882 getX86RegEncoding(MI, MemOperand + X86::AddrIndexReg);
883 VEX_X = ~(IndexRegEnc >> 3) & 1;
884 if (!HasVEX_4V) // Only needed with VSIB which don't use VVVV.
885 EVEX_V2 = ~(IndexRegEnc >> 4) & 1;
887 CurOp += X86::AddrNumOperands;
890 EVEX_aaa = getX86RegEncoding(MI, CurOp++);
893 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
894 VEX_4V = ~VRegEnc & 0xf;
895 EVEX_V2 = ~(VRegEnc >> 4) & 1;
898 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
899 VEX_R = ~(RegEnc >> 3) & 1;
900 EVEX_R2 = ~(RegEnc >> 4) & 1;
903 case X86II::MRMSrcMem: {
904 // MRMSrcMem instructions forms:
905 // src1(ModR/M), MemAddr
906 // src1(ModR/M), src2(VEX_4V), MemAddr
907 // src1(ModR/M), MemAddr, imm8
908 // src1(ModR/M), MemAddr, src2(Imm[7:4])
911 // dst(ModR/M.reg), src1(VEX_4V), src2(ModR/M), src3(Imm[7:4])
912 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
913 VEX_R = ~(RegEnc >> 3) & 1;
914 EVEX_R2 = ~(RegEnc >> 4) & 1;
917 EVEX_aaa = getX86RegEncoding(MI, CurOp++);
920 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
921 VEX_4V = ~VRegEnc & 0xf;
922 EVEX_V2 = ~(VRegEnc >> 4) & 1;
925 unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg);
926 VEX_B = ~(BaseRegEnc >> 3) & 1;
927 unsigned IndexRegEnc =
928 getX86RegEncoding(MI, MemOperand + X86::AddrIndexReg);
929 VEX_X = ~(IndexRegEnc >> 3) & 1;
930 if (!HasVEX_4V) // Only needed with VSIB which don't use VVVV.
931 EVEX_V2 = ~(IndexRegEnc >> 4) & 1;
935 case X86II::MRMSrcMem4VOp3: {
936 // Instruction format for 4VOp3:
937 // src1(ModR/M), MemAddr, src3(VEX_4V)
938 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
939 VEX_R = ~(RegEnc >> 3) & 1;
941 unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg);
942 VEX_B = ~(BaseRegEnc >> 3) & 1;
943 unsigned IndexRegEnc =
944 getX86RegEncoding(MI, MemOperand + X86::AddrIndexReg);
945 VEX_X = ~(IndexRegEnc >> 3) & 1;
947 VEX_4V = ~getX86RegEncoding(MI, CurOp + X86::AddrNumOperands) & 0xf;
950 case X86II::MRMSrcMemOp4: {
951 // dst(ModR/M.reg), src1(VEX_4V), src2(Imm[7:4]), src3(ModR/M),
952 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
953 VEX_R = ~(RegEnc >> 3) & 1;
955 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
956 VEX_4V = ~VRegEnc & 0xf;
958 unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg);
959 VEX_B = ~(BaseRegEnc >> 3) & 1;
960 unsigned IndexRegEnc =
961 getX86RegEncoding(MI, MemOperand + X86::AddrIndexReg);
962 VEX_X = ~(IndexRegEnc >> 3) & 1;
973 // MRM[0-9]m instructions forms:
975 // src1(VEX_4V), MemAddr
977 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
978 VEX_4V = ~VRegEnc & 0xf;
979 EVEX_V2 = ~(VRegEnc >> 4) & 1;
983 EVEX_aaa = getX86RegEncoding(MI, CurOp++);
985 unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg);
986 VEX_B = ~(BaseRegEnc >> 3) & 1;
987 unsigned IndexRegEnc =
988 getX86RegEncoding(MI, MemOperand + X86::AddrIndexReg);
989 VEX_X = ~(IndexRegEnc >> 3) & 1;
990 if (!HasVEX_4V) // Only needed with VSIB which don't use VVVV.
991 EVEX_V2 = ~(IndexRegEnc >> 4) & 1;
995 case X86II::MRMSrcReg: {
996 // MRMSrcReg instructions forms:
997 // dst(ModR/M), src1(VEX_4V), src2(ModR/M), src3(Imm[7:4])
998 // dst(ModR/M), src1(ModR/M)
999 // dst(ModR/M), src1(ModR/M), imm8
1002 // dst(ModR/M.reg), src1(VEX_4V), src2(Imm[7:4]), src3(ModR/M),
1003 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
1004 VEX_R = ~(RegEnc >> 3) & 1;
1005 EVEX_R2 = ~(RegEnc >> 4) & 1;
1008 EVEX_aaa = getX86RegEncoding(MI, CurOp++);
1011 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
1012 VEX_4V = ~VRegEnc & 0xf;
1013 EVEX_V2 = ~(VRegEnc >> 4) & 1;
1016 RegEnc = getX86RegEncoding(MI, CurOp++);
1017 VEX_B = ~(RegEnc >> 3) & 1;
1018 VEX_X = ~(RegEnc >> 4) & 1;
1022 unsigned RcOperand = NumOps - 1;
1023 assert(RcOperand >= CurOp);
1024 EVEX_rc = MI.getOperand(RcOperand).getImm();
1025 assert(EVEX_rc <= 3 && "Invalid rounding control!");
1031 case X86II::MRMSrcReg4VOp3: {
1032 // Instruction format for 4VOp3:
1033 // src1(ModR/M), src2(ModR/M), src3(VEX_4V)
1034 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
1035 VEX_R = ~(RegEnc >> 3) & 1;
1037 RegEnc = getX86RegEncoding(MI, CurOp++);
1038 VEX_B = ~(RegEnc >> 3) & 1;
1040 VEX_4V = ~getX86RegEncoding(MI, CurOp++) & 0xf;
1043 case X86II::MRMSrcRegOp4: {
1044 // dst(ModR/M.reg), src1(VEX_4V), src2(Imm[7:4]), src3(ModR/M),
1045 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
1046 VEX_R = ~(RegEnc >> 3) & 1;
1048 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
1049 VEX_4V = ~VRegEnc & 0xf;
1051 // Skip second register source (encoded in Imm[7:4])
1054 RegEnc = getX86RegEncoding(MI, CurOp++);
1055 VEX_B = ~(RegEnc >> 3) & 1;
1056 VEX_X = ~(RegEnc >> 4) & 1;
1059 case X86II::MRMDestReg: {
1060 // MRMDestReg instructions forms:
1061 // dst(ModR/M), src(ModR/M)
1062 // dst(ModR/M), src(ModR/M), imm8
1063 // dst(ModR/M), src1(VEX_4V), src2(ModR/M)
1064 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
1065 VEX_B = ~(RegEnc >> 3) & 1;
1066 VEX_X = ~(RegEnc >> 4) & 1;
1069 EVEX_aaa = getX86RegEncoding(MI, CurOp++);
1072 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
1073 VEX_4V = ~VRegEnc & 0xf;
1074 EVEX_V2 = ~(VRegEnc >> 4) & 1;
1077 RegEnc = getX86RegEncoding(MI, CurOp++);
1078 VEX_R = ~(RegEnc >> 3) & 1;
1079 EVEX_R2 = ~(RegEnc >> 4) & 1;
1091 case X86II::MRM7r: {
1092 // MRM0r-MRM7r instructions forms:
1093 // dst(VEX_4V), src(ModR/M), imm8
1095 unsigned VRegEnc = getX86RegEncoding(MI, CurOp++);
1096 VEX_4V = ~VRegEnc & 0xf;
1097 EVEX_V2 = ~(VRegEnc >> 4) & 1;
1100 EVEX_aaa = getX86RegEncoding(MI, CurOp++);
1102 unsigned RegEnc = getX86RegEncoding(MI, CurOp++);
1103 VEX_B = ~(RegEnc >> 3) & 1;
1104 VEX_X = ~(RegEnc >> 4) & 1;
1109 if (Encoding == X86II::VEX || Encoding == X86II::XOP) {
1110 // VEX opcode prefix can have 2 or 3 bytes
1113 // +-----+ +--------------+ +-------------------+
1114 // | C4h | | RXB | m-mmmm | | W | vvvv | L | pp |
1115 // +-----+ +--------------+ +-------------------+
1117 // +-----+ +-------------------+
1118 // | C5h | | R | vvvv | L | pp |
1119 // +-----+ +-------------------+
1121 // XOP uses a similar prefix:
1122 // +-----+ +--------------+ +-------------------+
1123 // | 8Fh | | RXB | m-mmmm | | W | vvvv | L | pp |
1124 // +-----+ +--------------+ +-------------------+
1125 uint8_t LastByte = VEX_PP | (VEX_L << 2) | (VEX_4V << 3);
1127 // Can we use the 2 byte VEX prefix?
1128 if (!(MI.getFlags() & X86::IP_USE_VEX3) && Encoding == X86II::VEX &&
1129 VEX_B && VEX_X && !VEX_W && (VEX_5M == 1)) {
1130 emitByte(0xC5, CurByte, OS);
1131 emitByte(LastByte | (VEX_R << 7), CurByte, OS);
1135 // 3 byte VEX prefix
1136 emitByte(Encoding == X86II::XOP ? 0x8F : 0xC4, CurByte, OS);
1137 emitByte(VEX_R << 7 | VEX_X << 6 | VEX_B << 5 | VEX_5M, CurByte, OS);
1138 emitByte(LastByte | (VEX_W << 7), CurByte, OS);
1140 assert(Encoding == X86II::EVEX && "unknown encoding!");
1141 // EVEX opcode prefix can have 4 bytes
1143 // +-----+ +--------------+ +-------------------+ +------------------------+
1144 // | 62h | | RXBR' | 00mm | | W | vvvv | U | pp | | z | L'L | b | v' | aaa |
1145 // +-----+ +--------------+ +-------------------+ +------------------------+
1146 assert((VEX_5M & 0x3) == VEX_5M &&
1147 "More than 2 significant bits in VEX.m-mmmm fields for EVEX!");
1149 emitByte(0x62, CurByte, OS);
1150 emitByte((VEX_R << 7) | (VEX_X << 6) | (VEX_B << 5) | (EVEX_R2 << 4) |
1153 emitByte((VEX_W << 7) | (VEX_4V << 3) | (EVEX_U << 2) | VEX_PP, CurByte,
1156 emitByte((EVEX_z << 7) | (EVEX_rc << 5) | (EVEX_b << 4) | (EVEX_V2 << 3) |
1160 emitByte((EVEX_z << 7) | (EVEX_L2 << 6) | (VEX_L << 5) | (EVEX_b << 4) |
1161 (EVEX_V2 << 3) | EVEX_aaa,
1166 /// Determine if the MCInst has to be encoded with a X86-64 REX prefix which
1167 /// specifies 1) 64-bit instructions, 2) non-default operand size, and 3) use
1168 /// of X86-64 extended registers.
1169 uint8_t X86MCCodeEmitter::determineREXPrefix(const MCInst &MI, uint64_t TSFlags,
1171 const MCInstrDesc &Desc) const {
1173 bool UsesHighByteReg = false;
1175 if (TSFlags & X86II::REX_W)
1176 REX |= 1 << 3; // set REX.W
1178 if (MI.getNumOperands() == 0)
1181 unsigned NumOps = MI.getNumOperands();
1182 unsigned CurOp = X86II::getOperandBias(Desc);
1184 // If it accesses SPL, BPL, SIL, or DIL, then it requires a 0x40 REX prefix.
1185 for (unsigned i = CurOp; i != NumOps; ++i) {
1186 const MCOperand &MO = MI.getOperand(i);
1189 unsigned Reg = MO.getReg();
1190 if (Reg == X86::AH || Reg == X86::BH || Reg == X86::CH || Reg == X86::DH)
1191 UsesHighByteReg = true;
1192 if (X86II::isX86_64NonExtLowByteReg(Reg))
1193 // FIXME: The caller of determineREXPrefix slaps this prefix onto anything
1194 // that returns non-zero.
1195 REX |= 0x40; // REX fixed encoding prefix
1198 switch (TSFlags & X86II::FormMask) {
1199 case X86II::AddRegFrm:
1200 REX |= isREXExtendedReg(MI, CurOp++) << 0; // REX.B
1202 case X86II::MRMSrcReg:
1203 case X86II::MRMSrcRegCC:
1204 REX |= isREXExtendedReg(MI, CurOp++) << 2; // REX.R
1205 REX |= isREXExtendedReg(MI, CurOp++) << 0; // REX.B
1207 case X86II::MRMSrcMem:
1208 case X86II::MRMSrcMemCC:
1209 REX |= isREXExtendedReg(MI, CurOp++) << 2; // REX.R
1210 REX |= isREXExtendedReg(MI, MemOperand + X86::AddrBaseReg) << 0; // REX.B
1211 REX |= isREXExtendedReg(MI, MemOperand + X86::AddrIndexReg) << 1; // REX.X
1212 CurOp += X86::AddrNumOperands;
1214 case X86II::MRMDestReg:
1215 REX |= isREXExtendedReg(MI, CurOp++) << 0; // REX.B
1216 REX |= isREXExtendedReg(MI, CurOp++) << 2; // REX.R
1218 case X86II::MRMDestMem:
1219 REX |= isREXExtendedReg(MI, MemOperand + X86::AddrBaseReg) << 0; // REX.B
1220 REX |= isREXExtendedReg(MI, MemOperand + X86::AddrIndexReg) << 1; // REX.X
1221 CurOp += X86::AddrNumOperands;
1222 REX |= isREXExtendedReg(MI, CurOp++) << 2; // REX.R
1224 case X86II::MRMXmCC:
1234 REX |= isREXExtendedReg(MI, MemOperand + X86::AddrBaseReg) << 0; // REX.B
1235 REX |= isREXExtendedReg(MI, MemOperand + X86::AddrIndexReg) << 1; // REX.X
1237 case X86II::MRMXrCC:
1247 REX |= isREXExtendedReg(MI, CurOp++) << 0; // REX.B
1250 if (REX && UsesHighByteReg)
1252 "Cannot encode high byte register in REX-prefixed instruction");
1257 /// Emit segment override opcode prefix as needed.
1258 void X86MCCodeEmitter::emitSegmentOverridePrefix(unsigned &CurByte,
1259 unsigned SegOperand,
1261 raw_ostream &OS) const {
1262 // Check for explicit segment override on memory operand.
1263 switch (MI.getOperand(SegOperand).getReg()) {
1265 llvm_unreachable("Unknown segment register!");
1269 emitByte(0x2E, CurByte, OS);
1272 emitByte(0x36, CurByte, OS);
1275 emitByte(0x3E, CurByte, OS);
1278 emitByte(0x26, CurByte, OS);
1281 emitByte(0x64, CurByte, OS);
1284 emitByte(0x65, CurByte, OS);
1289 /// Emit all instruction prefixes prior to the opcode.
1291 /// \param MemOperand the operand # of the start of a memory operand if present.
1292 /// If not present, it is -1.
1294 /// \returns true if a REX prefix was used.
1295 bool X86MCCodeEmitter::emitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
1296 int MemOperand, const MCInst &MI,
1297 const MCInstrDesc &Desc,
1298 const MCSubtargetInfo &STI,
1299 raw_ostream &OS) const {
1301 // Emit the operand size opcode prefix as needed.
1302 if ((TSFlags & X86II::OpSizeMask) ==
1303 (STI.hasFeature(X86::Mode16Bit) ? X86II::OpSize32 : X86II::OpSize16))
1304 emitByte(0x66, CurByte, OS);
1306 // Emit the LOCK opcode prefix.
1307 if (TSFlags & X86II::LOCK || MI.getFlags() & X86::IP_HAS_LOCK)
1308 emitByte(0xF0, CurByte, OS);
1310 // Emit the NOTRACK opcode prefix.
1311 if (TSFlags & X86II::NOTRACK || MI.getFlags() & X86::IP_HAS_NOTRACK)
1312 emitByte(0x3E, CurByte, OS);
1314 switch (TSFlags & X86II::OpPrefixMask) {
1315 case X86II::PD: // 66
1316 emitByte(0x66, CurByte, OS);
1318 case X86II::XS: // F3
1319 emitByte(0xF3, CurByte, OS);
1321 case X86II::XD: // F2
1322 emitByte(0xF2, CurByte, OS);
1326 // Handle REX prefix.
1327 // FIXME: Can this come before F2 etc to simplify emission?
1328 if (STI.hasFeature(X86::Mode64Bit)) {
1329 if (uint8_t REX = determineREXPrefix(MI, TSFlags, MemOperand, Desc)) {
1330 emitByte(0x40 | REX, CurByte, OS);
1334 assert(!(TSFlags & X86II::REX_W) && "REX.W requires 64bit mode.");
1337 // 0x0F escape code must be emitted just before the opcode.
1338 switch (TSFlags & X86II::OpMapMask) {
1339 case X86II::TB: // Two-byte opcode map
1340 case X86II::T8: // 0F 38
1341 case X86II::TA: // 0F 3A
1342 case X86II::ThreeDNow: // 0F 0F, second 0F emitted by caller.
1343 emitByte(0x0F, CurByte, OS);
1347 switch (TSFlags & X86II::OpMapMask) {
1348 case X86II::T8: // 0F 38
1349 emitByte(0x38, CurByte, OS);
1351 case X86II::TA: // 0F 3A
1352 emitByte(0x3A, CurByte, OS);
1358 void X86MCCodeEmitter::emitPrefix(const MCInst &MI, raw_ostream &OS,
1359 const MCSubtargetInfo &STI) const {
1360 unsigned Opcode = MI.getOpcode();
1361 const MCInstrDesc &Desc = MCII.get(Opcode);
1362 uint64_t TSFlags = Desc.TSFlags;
1364 // Pseudo instructions don't get encoded.
1365 if ((TSFlags & X86II::FormMask) == X86II::Pseudo)
1368 unsigned CurOp = X86II::getOperandBias(Desc);
1370 // Keep track of the current byte being emitted.
1371 unsigned CurByte = 0;
1374 emitPrefixImpl(TSFlags, CurOp, CurByte, Rex, MI, Desc, STI, OS);
1377 void X86MCCodeEmitter::encodeInstruction(const MCInst &MI, raw_ostream &OS,
1378 SmallVectorImpl<MCFixup> &Fixups,
1379 const MCSubtargetInfo &STI) const {
1380 unsigned Opcode = MI.getOpcode();
1381 const MCInstrDesc &Desc = MCII.get(Opcode);
1382 uint64_t TSFlags = Desc.TSFlags;
1384 // Pseudo instructions don't get encoded.
1385 if ((TSFlags & X86II::FormMask) == X86II::Pseudo)
1388 unsigned NumOps = Desc.getNumOperands();
1389 unsigned CurOp = X86II::getOperandBias(Desc);
1391 // Keep track of the current byte being emitted.
1392 unsigned CurByte = 0;
1395 emitPrefixImpl(TSFlags, CurOp, CurByte, Rex, MI, Desc, STI, OS);
1397 // It uses the VEX.VVVV field?
1398 bool HasVEX_4V = TSFlags & X86II::VEX_4V;
1399 bool HasVEX_I8Reg = (TSFlags & X86II::ImmMask) == X86II::Imm8Reg;
1401 // It uses the EVEX.aaa field?
1402 bool HasEVEX_K = TSFlags & X86II::EVEX_K;
1403 bool HasEVEX_RC = TSFlags & X86II::EVEX_RC;
1405 // Used if a register is encoded in 7:4 of immediate.
1406 unsigned I8RegNum = 0;
1408 uint8_t BaseOpcode = X86II::getBaseOpcodeFor(TSFlags);
1410 if ((TSFlags & X86II::OpMapMask) == X86II::ThreeDNow)
1411 BaseOpcode = 0x0F; // Weird 3DNow! encoding.
1413 unsigned OpcodeOffset = 0;
1415 uint64_t Form = TSFlags & X86II::FormMask;
1418 errs() << "FORM: " << Form << "\n";
1419 llvm_unreachable("Unknown FormMask value in X86MCCodeEmitter!");
1421 llvm_unreachable("Pseudo instruction shouldn't be emitted");
1422 case X86II::RawFrmDstSrc:
1423 case X86II::RawFrmSrc:
1424 case X86II::RawFrmDst:
1425 emitByte(BaseOpcode, CurByte, OS);
1427 case X86II::AddCCFrm: {
1428 // This will be added to the opcode in the fallthrough.
1429 OpcodeOffset = MI.getOperand(NumOps - 1).getImm();
1430 assert(OpcodeOffset < 16 && "Unexpected opcode offset!");
1431 --NumOps; // Drop the operand from the end.
1434 emitByte(BaseOpcode + OpcodeOffset, CurByte, OS);
1436 if (!STI.hasFeature(X86::Mode64Bit) || !isPCRel32Branch(MI, MCII))
1439 const MCOperand &Op = MI.getOperand(CurOp++);
1440 emitImmediate(Op, MI.getLoc(), X86II::getSizeOfImm(TSFlags),
1441 MCFixupKind(X86::reloc_branch_4byte_pcrel), CurByte, OS,
1445 case X86II::RawFrmMemOffs:
1446 emitByte(BaseOpcode, CurByte, OS);
1447 emitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
1448 X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
1449 CurByte, OS, Fixups);
1450 ++CurOp; // skip segment operand
1452 case X86II::RawFrmImm8:
1453 emitByte(BaseOpcode, CurByte, OS);
1454 emitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
1455 X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
1456 CurByte, OS, Fixups);
1457 emitImmediate(MI.getOperand(CurOp++), MI.getLoc(), 1, FK_Data_1, CurByte,
1460 case X86II::RawFrmImm16:
1461 emitByte(BaseOpcode, CurByte, OS);
1462 emitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
1463 X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
1464 CurByte, OS, Fixups);
1465 emitImmediate(MI.getOperand(CurOp++), MI.getLoc(), 2, FK_Data_2, CurByte,
1469 case X86II::AddRegFrm:
1470 emitByte(BaseOpcode + getX86RegNum(MI.getOperand(CurOp++)), CurByte, OS);
1473 case X86II::MRMDestReg: {
1474 emitByte(BaseOpcode, CurByte, OS);
1475 unsigned SrcRegNum = CurOp + 1;
1477 if (HasEVEX_K) // Skip writemask
1480 if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV)
1483 emitRegModRMByte(MI.getOperand(CurOp),
1484 getX86RegNum(MI.getOperand(SrcRegNum)), CurByte, OS);
1485 CurOp = SrcRegNum + 1;
1488 case X86II::MRMDestMem: {
1489 emitByte(BaseOpcode, CurByte, OS);
1490 unsigned SrcRegNum = CurOp + X86::AddrNumOperands;
1492 if (HasEVEX_K) // Skip writemask
1495 if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV)
1498 emitMemModRMByte(MI, CurOp, getX86RegNum(MI.getOperand(SrcRegNum)), TSFlags,
1499 Rex, CurByte, OS, Fixups, STI);
1500 CurOp = SrcRegNum + 1;
1503 case X86II::MRMSrcReg: {
1504 emitByte(BaseOpcode, CurByte, OS);
1505 unsigned SrcRegNum = CurOp + 1;
1507 if (HasEVEX_K) // Skip writemask
1510 if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV)
1513 emitRegModRMByte(MI.getOperand(SrcRegNum),
1514 getX86RegNum(MI.getOperand(CurOp)), CurByte, OS);
1515 CurOp = SrcRegNum + 1;
1517 I8RegNum = getX86RegEncoding(MI, CurOp++);
1518 // do not count the rounding control operand
1523 case X86II::MRMSrcReg4VOp3: {
1524 emitByte(BaseOpcode, CurByte, OS);
1525 unsigned SrcRegNum = CurOp + 1;
1527 emitRegModRMByte(MI.getOperand(SrcRegNum),
1528 getX86RegNum(MI.getOperand(CurOp)), CurByte, OS);
1529 CurOp = SrcRegNum + 1;
1530 ++CurOp; // Encoded in VEX.VVVV
1533 case X86II::MRMSrcRegOp4: {
1534 emitByte(BaseOpcode, CurByte, OS);
1535 unsigned SrcRegNum = CurOp + 1;
1537 // Skip 1st src (which is encoded in VEX_VVVV)
1540 // Capture 2nd src (which is encoded in Imm[7:4])
1541 assert(HasVEX_I8Reg && "MRMSrcRegOp4 should imply VEX_I8Reg");
1542 I8RegNum = getX86RegEncoding(MI, SrcRegNum++);
1544 emitRegModRMByte(MI.getOperand(SrcRegNum),
1545 getX86RegNum(MI.getOperand(CurOp)), CurByte, OS);
1546 CurOp = SrcRegNum + 1;
1549 case X86II::MRMSrcRegCC: {
1550 unsigned FirstOp = CurOp++;
1551 unsigned SecondOp = CurOp++;
1553 unsigned CC = MI.getOperand(CurOp++).getImm();
1554 emitByte(BaseOpcode + CC, CurByte, OS);
1556 emitRegModRMByte(MI.getOperand(SecondOp),
1557 getX86RegNum(MI.getOperand(FirstOp)), CurByte, OS);
1560 case X86II::MRMSrcMem: {
1561 unsigned FirstMemOp = CurOp + 1;
1563 if (HasEVEX_K) // Skip writemask
1567 ++FirstMemOp; // Skip the register source (which is encoded in VEX_VVVV).
1569 emitByte(BaseOpcode, CurByte, OS);
1571 emitMemModRMByte(MI, FirstMemOp, getX86RegNum(MI.getOperand(CurOp)),
1572 TSFlags, Rex, CurByte, OS, Fixups, STI);
1573 CurOp = FirstMemOp + X86::AddrNumOperands;
1575 I8RegNum = getX86RegEncoding(MI, CurOp++);
1578 case X86II::MRMSrcMem4VOp3: {
1579 unsigned FirstMemOp = CurOp + 1;
1581 emitByte(BaseOpcode, CurByte, OS);
1583 emitMemModRMByte(MI, FirstMemOp, getX86RegNum(MI.getOperand(CurOp)),
1584 TSFlags, Rex, CurByte, OS, Fixups, STI);
1585 CurOp = FirstMemOp + X86::AddrNumOperands;
1586 ++CurOp; // Encoded in VEX.VVVV.
1589 case X86II::MRMSrcMemOp4: {
1590 unsigned FirstMemOp = CurOp + 1;
1592 ++FirstMemOp; // Skip the register source (which is encoded in VEX_VVVV).
1594 // Capture second register source (encoded in Imm[7:4])
1595 assert(HasVEX_I8Reg && "MRMSrcRegOp4 should imply VEX_I8Reg");
1596 I8RegNum = getX86RegEncoding(MI, FirstMemOp++);
1598 emitByte(BaseOpcode, CurByte, OS);
1600 emitMemModRMByte(MI, FirstMemOp, getX86RegNum(MI.getOperand(CurOp)),
1601 TSFlags, Rex, CurByte, OS, Fixups, STI);
1602 CurOp = FirstMemOp + X86::AddrNumOperands;
1605 case X86II::MRMSrcMemCC: {
1606 unsigned RegOp = CurOp++;
1607 unsigned FirstMemOp = CurOp;
1608 CurOp = FirstMemOp + X86::AddrNumOperands;
1610 unsigned CC = MI.getOperand(CurOp++).getImm();
1611 emitByte(BaseOpcode + CC, CurByte, OS);
1613 emitMemModRMByte(MI, FirstMemOp, getX86RegNum(MI.getOperand(RegOp)),
1614 TSFlags, Rex, CurByte, OS, Fixups, STI);
1618 case X86II::MRMXrCC: {
1619 unsigned RegOp = CurOp++;
1621 unsigned CC = MI.getOperand(CurOp++).getImm();
1622 emitByte(BaseOpcode + CC, CurByte, OS);
1623 emitRegModRMByte(MI.getOperand(RegOp), 0, CurByte, OS);
1636 if (HasVEX_4V) // Skip the register dst (which is encoded in VEX_VVVV).
1638 if (HasEVEX_K) // Skip writemask
1640 emitByte(BaseOpcode, CurByte, OS);
1641 emitRegModRMByte(MI.getOperand(CurOp++),
1642 (Form == X86II::MRMXr) ? 0 : Form - X86II::MRM0r, CurByte,
1646 case X86II::MRMXmCC: {
1647 unsigned FirstMemOp = CurOp;
1648 CurOp = FirstMemOp + X86::AddrNumOperands;
1650 unsigned CC = MI.getOperand(CurOp++).getImm();
1651 emitByte(BaseOpcode + CC, CurByte, OS);
1653 emitMemModRMByte(MI, FirstMemOp, 0, TSFlags, Rex, CurByte, OS, Fixups, STI);
1666 if (HasVEX_4V) // Skip the register dst (which is encoded in VEX_VVVV).
1668 if (HasEVEX_K) // Skip writemask
1670 emitByte(BaseOpcode, CurByte, OS);
1671 emitMemModRMByte(MI, CurOp,
1672 (Form == X86II::MRMXm) ? 0 : Form - X86II::MRM0m, TSFlags,
1673 Rex, CurByte, OS, Fixups, STI);
1674 CurOp += X86::AddrNumOperands;
1741 emitByte(BaseOpcode, CurByte, OS);
1742 emitByte(0xC0 + Form - X86II::MRM_C0, CurByte, OS);
1747 // The last source register of a 4 operand instruction in AVX is encoded
1748 // in bits[7:4] of a immediate byte.
1749 assert(I8RegNum < 16 && "Register encoding out of range");
1751 if (CurOp != NumOps) {
1752 unsigned Val = MI.getOperand(CurOp++).getImm();
1753 assert(Val < 16 && "Immediate operand value out of range");
1756 emitImmediate(MCOperand::createImm(I8RegNum), MI.getLoc(), 1, FK_Data_1,
1757 CurByte, OS, Fixups);
1759 // If there is a remaining operand, it must be a trailing immediate. Emit it
1760 // according to the right size for the instruction. Some instructions
1761 // (SSE4a extrq and insertq) have two trailing immediates.
1762 while (CurOp != NumOps && NumOps - CurOp <= 2) {
1763 emitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
1764 X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
1765 CurByte, OS, Fixups);
1769 if ((TSFlags & X86II::OpMapMask) == X86II::ThreeDNow)
1770 emitByte(X86II::getBaseOpcodeFor(TSFlags), CurByte, OS);
1774 if (/*!Desc.isVariadic() &&*/ CurOp != NumOps) {
1775 errs() << "Cannot encode all operands of: ";
1783 MCCodeEmitter *llvm::createX86MCCodeEmitter(const MCInstrInfo &MCII,
1784 const MCRegisterInfo &MRI,
1786 return new X86MCCodeEmitter(MCII, Ctx);