1 //===-- X86/X86MCCodeEmitter.cpp - Convert X86 code to machine code -------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the X86MCCodeEmitter class.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "x86-emitter"
16 #include "X86InstrInfo.h"
17 #include "X86FixupKinds.h"
18 #include "llvm/MC/MCCodeEmitter.h"
19 #include "llvm/MC/MCExpr.h"
20 #include "llvm/MC/MCInst.h"
21 #include "llvm/Support/raw_ostream.h"
25 class X86MCCodeEmitter : public MCCodeEmitter {
26 X86MCCodeEmitter(const X86MCCodeEmitter &); // DO NOT IMPLEMENT
27 void operator=(const X86MCCodeEmitter &); // DO NOT IMPLEMENT
28 const TargetMachine &TM;
29 const TargetInstrInfo &TII;
33 X86MCCodeEmitter(TargetMachine &tm, MCContext &ctx, bool is64Bit)
34 : TM(tm), TII(*TM.getInstrInfo()), Ctx(ctx) {
35 Is64BitMode = is64Bit;
38 ~X86MCCodeEmitter() {}
40 unsigned getNumFixupKinds() const {
44 const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const {
45 const static MCFixupKindInfo Infos[] = {
46 { "reloc_pcrel_4byte", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel },
47 { "reloc_pcrel_1byte", 0, 1 * 8, MCFixupKindInfo::FKF_IsPCRel },
48 { "reloc_pcrel_2byte", 0, 2 * 8, MCFixupKindInfo::FKF_IsPCRel },
49 { "reloc_riprel_4byte", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel },
50 { "reloc_riprel_4byte_movq_load", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel }
53 if (Kind < FirstTargetFixupKind)
54 return MCCodeEmitter::getFixupKindInfo(Kind);
56 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
58 return Infos[Kind - FirstTargetFixupKind];
61 static unsigned GetX86RegNum(const MCOperand &MO) {
62 return X86RegisterInfo::getX86RegNum(MO.getReg());
65 // On regular x86, both XMM0-XMM7 and XMM8-XMM15 are encoded in the range
66 // 0-7 and the difference between the 2 groups is given by the REX prefix.
67 // In the VEX prefix, registers are seen sequencially from 0-15 and encoded
68 // in 1's complement form, example:
70 // ModRM field => XMM9 => 1
71 // VEX.VVVV => XMM9 => ~9
73 // See table 4-35 of Intel AVX Programming Reference for details.
74 static unsigned char getVEXRegisterEncoding(const MCInst &MI,
76 unsigned SrcReg = MI.getOperand(OpNum).getReg();
77 unsigned SrcRegNum = GetX86RegNum(MI.getOperand(OpNum));
78 if (SrcReg >= X86::XMM8 && SrcReg <= X86::XMM15)
81 // The registers represented through VEX_VVVV should
82 // be encoded in 1's complement form.
83 return (~SrcRegNum) & 0xf;
86 void EmitByte(unsigned char C, unsigned &CurByte, raw_ostream &OS) const {
91 void EmitConstant(uint64_t Val, unsigned Size, unsigned &CurByte,
92 raw_ostream &OS) const {
93 // Output the constant in little endian byte order.
94 for (unsigned i = 0; i != Size; ++i) {
95 EmitByte(Val & 255, CurByte, OS);
100 void EmitImmediate(const MCOperand &Disp,
101 unsigned ImmSize, MCFixupKind FixupKind,
102 unsigned &CurByte, raw_ostream &OS,
103 SmallVectorImpl<MCFixup> &Fixups,
104 int ImmOffset = 0) const;
106 inline static unsigned char ModRMByte(unsigned Mod, unsigned RegOpcode,
108 assert(Mod < 4 && RegOpcode < 8 && RM < 8 && "ModRM Fields out of range!");
109 return RM | (RegOpcode << 3) | (Mod << 6);
112 void EmitRegModRMByte(const MCOperand &ModRMReg, unsigned RegOpcodeFld,
113 unsigned &CurByte, raw_ostream &OS) const {
114 EmitByte(ModRMByte(3, RegOpcodeFld, GetX86RegNum(ModRMReg)), CurByte, OS);
117 void EmitSIBByte(unsigned SS, unsigned Index, unsigned Base,
118 unsigned &CurByte, raw_ostream &OS) const {
119 // SIB byte is in the same format as the ModRMByte.
120 EmitByte(ModRMByte(SS, Index, Base), CurByte, OS);
124 void EmitMemModRMByte(const MCInst &MI, unsigned Op,
125 unsigned RegOpcodeField,
126 uint64_t TSFlags, unsigned &CurByte, raw_ostream &OS,
127 SmallVectorImpl<MCFixup> &Fixups) const;
129 void EncodeInstruction(const MCInst &MI, raw_ostream &OS,
130 SmallVectorImpl<MCFixup> &Fixups) const;
132 void EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
133 const MCInst &MI, const TargetInstrDesc &Desc,
134 raw_ostream &OS) const;
136 void EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand,
137 const MCInst &MI, const TargetInstrDesc &Desc,
138 raw_ostream &OS) const;
141 } // end anonymous namespace
144 MCCodeEmitter *llvm::createX86_32MCCodeEmitter(const Target &,
147 return new X86MCCodeEmitter(TM, Ctx, false);
150 MCCodeEmitter *llvm::createX86_64MCCodeEmitter(const Target &,
153 return new X86MCCodeEmitter(TM, Ctx, true);
156 /// isDisp8 - Return true if this signed displacement fits in a 8-bit
157 /// sign-extended field.
158 static bool isDisp8(int Value) {
159 return Value == (signed char)Value;
162 /// getImmFixupKind - Return the appropriate fixup kind to use for an immediate
163 /// in an instruction with the specified TSFlags.
164 static MCFixupKind getImmFixupKind(uint64_t TSFlags) {
165 unsigned Size = X86II::getSizeOfImm(TSFlags);
166 bool isPCRel = X86II::isImmPCRel(TSFlags);
169 default: assert(0 && "Unknown immediate size");
170 case 1: return isPCRel ? MCFixupKind(X86::reloc_pcrel_1byte) : FK_Data_1;
171 case 2: return isPCRel ? MCFixupKind(X86::reloc_pcrel_2byte) : FK_Data_2;
172 case 4: return isPCRel ? MCFixupKind(X86::reloc_pcrel_4byte) : FK_Data_4;
173 case 8: assert(!isPCRel); return FK_Data_8;
178 void X86MCCodeEmitter::
179 EmitImmediate(const MCOperand &DispOp, unsigned Size, MCFixupKind FixupKind,
180 unsigned &CurByte, raw_ostream &OS,
181 SmallVectorImpl<MCFixup> &Fixups, int ImmOffset) const {
182 // If this is a simple integer displacement that doesn't require a relocation,
184 if (DispOp.isImm()) {
185 // FIXME: is this right for pc-rel encoding?? Probably need to emit this as
187 EmitConstant(DispOp.getImm()+ImmOffset, Size, CurByte, OS);
191 // If we have an immoffset, add it to the expression.
192 const MCExpr *Expr = DispOp.getExpr();
194 // If the fixup is pc-relative, we need to bias the value to be relative to
195 // the start of the field, not the end of the field.
196 if (FixupKind == MCFixupKind(X86::reloc_pcrel_4byte) ||
197 FixupKind == MCFixupKind(X86::reloc_riprel_4byte) ||
198 FixupKind == MCFixupKind(X86::reloc_riprel_4byte_movq_load))
200 if (FixupKind == MCFixupKind(X86::reloc_pcrel_2byte))
202 if (FixupKind == MCFixupKind(X86::reloc_pcrel_1byte))
206 Expr = MCBinaryExpr::CreateAdd(Expr, MCConstantExpr::Create(ImmOffset, Ctx),
209 // Emit a symbolic constant as a fixup and 4 zeros.
210 Fixups.push_back(MCFixup::Create(CurByte, Expr, FixupKind));
211 EmitConstant(0, Size, CurByte, OS);
214 void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
215 unsigned RegOpcodeField,
216 uint64_t TSFlags, unsigned &CurByte,
218 SmallVectorImpl<MCFixup> &Fixups) const{
219 const MCOperand &Disp = MI.getOperand(Op+3);
220 const MCOperand &Base = MI.getOperand(Op);
221 const MCOperand &Scale = MI.getOperand(Op+1);
222 const MCOperand &IndexReg = MI.getOperand(Op+2);
223 unsigned BaseReg = Base.getReg();
225 // Handle %rip relative addressing.
226 if (BaseReg == X86::RIP) { // [disp32+RIP] in X86-64 mode
227 assert(Is64BitMode && "Rip-relative addressing requires 64-bit mode");
228 assert(IndexReg.getReg() == 0 && "Invalid rip-relative address");
229 EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS);
231 unsigned FixupKind = X86::reloc_riprel_4byte;
233 // movq loads are handled with a special relocation form which allows the
234 // linker to eliminate some loads for GOT references which end up in the
235 // same linkage unit.
236 if (MI.getOpcode() == X86::MOV64rm ||
237 MI.getOpcode() == X86::MOV64rm_TC)
238 FixupKind = X86::reloc_riprel_4byte_movq_load;
240 // rip-relative addressing is actually relative to the *next* instruction.
241 // Since an immediate can follow the mod/rm byte for an instruction, this
242 // means that we need to bias the immediate field of the instruction with
243 // the size of the immediate field. If we have this case, add it into the
244 // expression to emit.
245 int ImmSize = X86II::hasImm(TSFlags) ? X86II::getSizeOfImm(TSFlags) : 0;
247 EmitImmediate(Disp, 4, MCFixupKind(FixupKind),
248 CurByte, OS, Fixups, -ImmSize);
252 unsigned BaseRegNo = BaseReg ? GetX86RegNum(Base) : -1U;
254 // Determine whether a SIB byte is needed.
255 // If no BaseReg, issue a RIP relative instruction only if the MCE can
256 // resolve addresses on-the-fly, otherwise use SIB (Intel Manual 2A, table
257 // 2-7) and absolute references.
259 if (// The SIB byte must be used if there is an index register.
260 IndexReg.getReg() == 0 &&
261 // The SIB byte must be used if the base is ESP/RSP/R12, all of which
262 // encode to an R/M value of 4, which indicates that a SIB byte is
264 BaseRegNo != N86::ESP &&
265 // If there is no base register and we're in 64-bit mode, we need a SIB
266 // byte to emit an addr that is just 'disp32' (the non-RIP relative form).
267 (!Is64BitMode || BaseReg != 0)) {
269 if (BaseReg == 0) { // [disp32] in X86-32 mode
270 EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS);
271 EmitImmediate(Disp, 4, FK_Data_4, CurByte, OS, Fixups);
275 // If the base is not EBP/ESP and there is no displacement, use simple
276 // indirect register encoding, this handles addresses like [EAX]. The
277 // encoding for [EBP] with no displacement means [disp32] so we handle it
278 // by emitting a displacement of 0 below.
279 if (Disp.isImm() && Disp.getImm() == 0 && BaseRegNo != N86::EBP) {
280 EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS);
284 // Otherwise, if the displacement fits in a byte, encode as [REG+disp8].
285 if (Disp.isImm() && isDisp8(Disp.getImm())) {
286 EmitByte(ModRMByte(1, RegOpcodeField, BaseRegNo), CurByte, OS);
287 EmitImmediate(Disp, 1, FK_Data_1, CurByte, OS, Fixups);
291 // Otherwise, emit the most general non-SIB encoding: [REG+disp32]
292 EmitByte(ModRMByte(2, RegOpcodeField, BaseRegNo), CurByte, OS);
293 EmitImmediate(Disp, 4, FK_Data_4, CurByte, OS, Fixups);
297 // We need a SIB byte, so start by outputting the ModR/M byte first
298 assert(IndexReg.getReg() != X86::ESP &&
299 IndexReg.getReg() != X86::RSP && "Cannot use ESP as index reg!");
301 bool ForceDisp32 = false;
302 bool ForceDisp8 = false;
304 // If there is no base register, we emit the special case SIB byte with
305 // MOD=0, BASE=5, to JUST get the index, scale, and displacement.
306 EmitByte(ModRMByte(0, RegOpcodeField, 4), CurByte, OS);
308 } else if (!Disp.isImm()) {
309 // Emit the normal disp32 encoding.
310 EmitByte(ModRMByte(2, RegOpcodeField, 4), CurByte, OS);
312 } else if (Disp.getImm() == 0 &&
313 // Base reg can't be anything that ends up with '5' as the base
314 // reg, it is the magic [*] nomenclature that indicates no base.
315 BaseRegNo != N86::EBP) {
316 // Emit no displacement ModR/M byte
317 EmitByte(ModRMByte(0, RegOpcodeField, 4), CurByte, OS);
318 } else if (isDisp8(Disp.getImm())) {
319 // Emit the disp8 encoding.
320 EmitByte(ModRMByte(1, RegOpcodeField, 4), CurByte, OS);
321 ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
323 // Emit the normal disp32 encoding.
324 EmitByte(ModRMByte(2, RegOpcodeField, 4), CurByte, OS);
327 // Calculate what the SS field value should be...
328 static const unsigned SSTable[] = { ~0, 0, 1, ~0, 2, ~0, ~0, ~0, 3 };
329 unsigned SS = SSTable[Scale.getImm()];
332 // Handle the SIB byte for the case where there is no base, see Intel
333 // Manual 2A, table 2-7. The displacement has already been output.
335 if (IndexReg.getReg())
336 IndexRegNo = GetX86RegNum(IndexReg);
337 else // Examples: [ESP+1*<noreg>+4] or [scaled idx]+disp32 (MOD=0,BASE=5)
339 EmitSIBByte(SS, IndexRegNo, 5, CurByte, OS);
342 if (IndexReg.getReg())
343 IndexRegNo = GetX86RegNum(IndexReg);
345 IndexRegNo = 4; // For example [ESP+1*<noreg>+4]
346 EmitSIBByte(SS, IndexRegNo, GetX86RegNum(Base), CurByte, OS);
349 // Do we need to output a displacement?
351 EmitImmediate(Disp, 1, FK_Data_1, CurByte, OS, Fixups);
352 else if (ForceDisp32 || Disp.getImm() != 0)
353 EmitImmediate(Disp, 4, FK_Data_4, CurByte, OS, Fixups);
356 /// EmitVEXOpcodePrefix - AVX instructions are encoded using a opcode prefix
358 void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
359 const MCInst &MI, const TargetInstrDesc &Desc,
360 raw_ostream &OS) const {
361 bool HasVEX_4V = false;
362 if ((TSFlags >> 32) & X86II::VEX_4V)
365 // VEX_R: opcode externsion equivalent to REX.R in
366 // 1's complement (inverted) form
368 // 1: Same as REX_R=0 (must be 1 in 32-bit mode)
369 // 0: Same as REX_R=1 (64 bit mode only)
371 unsigned char VEX_R = 0x1;
373 // VEX_X: equivalent to REX.X, only used when a
374 // register is used for index in SIB Byte.
376 // 1: Same as REX.X=0 (must be 1 in 32-bit mode)
377 // 0: Same as REX.X=1 (64-bit mode only)
378 unsigned char VEX_X = 0x1;
382 // 1: Same as REX_B=0 (ignored in 32-bit mode)
383 // 0: Same as REX_B=1 (64 bit mode only)
385 unsigned char VEX_B = 0x1;
387 // VEX_W: opcode specific (use like REX.W, or used for
388 // opcode extension, or ignored, depending on the opcode byte)
389 unsigned char VEX_W = 0;
391 // VEX_5M (VEX m-mmmmm field):
393 // 0b00000: Reserved for future use
394 // 0b00001: implied 0F leading opcode
395 // 0b00010: implied 0F 38 leading opcode bytes
396 // 0b00011: implied 0F 3A leading opcode bytes
397 // 0b00100-0b11111: Reserved for future use
399 unsigned char VEX_5M = 0x1;
401 // VEX_4V (VEX vvvv field): a register specifier
402 // (in 1's complement form) or 1111 if unused.
403 unsigned char VEX_4V = 0xf;
405 // VEX_L (Vector Length):
407 // 0: scalar or 128-bit vector
410 unsigned char VEX_L = 0;
412 // VEX_PP: opcode extension providing equivalent
413 // functionality of a SIMD prefix
420 unsigned char VEX_PP = 0;
422 // Encode the operand size opcode prefix as needed.
423 if (TSFlags & X86II::OpSize)
426 if ((TSFlags >> 32) & X86II::VEX_W)
429 switch (TSFlags & X86II::Op0Mask) {
430 default: assert(0 && "Invalid prefix!");
431 case X86II::T8: // 0F 38
434 case X86II::TA: // 0F 3A
437 case X86II::TF: // F2 0F 38
441 case X86II::XS: // F3 0F
444 case X86II::XD: // F2 0F
447 case X86II::TB: // Bypass: Not used by VEX
452 unsigned NumOps = MI.getNumOperands();
455 switch (TSFlags & X86II::FormMask) {
456 case X86II::MRMInitReg: assert(0 && "FIXME: Remove this!");
457 case X86II::MRM0m: case X86II::MRM1m:
458 case X86II::MRM2m: case X86II::MRM3m:
459 case X86II::MRM4m: case X86II::MRM5m:
460 case X86II::MRM6m: case X86II::MRM7m:
461 case X86II::MRMDestMem:
462 NumOps = CurOp = X86::AddrNumOperands;
463 case X86II::MRMSrcMem:
464 case X86II::MRMSrcReg:
465 if (MI.getNumOperands() > CurOp && MI.getOperand(CurOp).isReg() &&
466 X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
469 // CurOp and NumOps are equal when VEX_R represents a register used
470 // to index a memory destination (which is the last operand)
471 CurOp = (CurOp == NumOps) ? 0 : CurOp+1;
474 VEX_4V = getVEXRegisterEncoding(MI, CurOp);
478 // If the last register should be encoded in the immediate field
479 // do not use any bit from VEX prefix to this register, ignore it
480 if ((TSFlags >> 32) & X86II::VEX_I8IMM)
483 for (; CurOp != NumOps; ++CurOp) {
484 const MCOperand &MO = MI.getOperand(CurOp);
485 if (MO.isReg() && X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
487 if (!VEX_B && MO.isReg() &&
488 ((TSFlags & X86II::FormMask) == X86II::MRMSrcMem) &&
489 X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
493 default: // MRMDestReg, MRM0r-MRM7r
494 if (MI.getOperand(CurOp).isReg() &&
495 X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
499 VEX_4V = getVEXRegisterEncoding(MI, CurOp);
502 for (; CurOp != NumOps; ++CurOp) {
503 const MCOperand &MO = MI.getOperand(CurOp);
504 if (MO.isReg() && !HasVEX_4V &&
505 X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
509 assert(0 && "Not implemented!");
512 // VEX opcode prefix can have 2 or 3 bytes
515 // +-----+ +--------------+ +-------------------+
516 // | C4h | | RXB | m-mmmm | | W | vvvv | L | pp |
517 // +-----+ +--------------+ +-------------------+
519 // +-----+ +-------------------+
520 // | C5h | | R | vvvv | L | pp |
521 // +-----+ +-------------------+
523 unsigned char LastByte = VEX_PP | (VEX_L << 2) | (VEX_4V << 3);
525 if (VEX_B && VEX_X && !VEX_W && (VEX_5M == 1)) { // 2 byte VEX prefix
526 EmitByte(0xC5, CurByte, OS);
527 EmitByte(LastByte | (VEX_R << 7), CurByte, OS);
532 EmitByte(0xC4, CurByte, OS);
533 EmitByte(VEX_R << 7 | VEX_X << 6 | VEX_B << 5 | VEX_5M, CurByte, OS);
534 EmitByte(LastByte | (VEX_W << 7), CurByte, OS);
537 /// DetermineREXPrefix - Determine if the MCInst has to be encoded with a X86-64
538 /// REX prefix which specifies 1) 64-bit instructions, 2) non-default operand
539 /// size, and 3) use of X86-64 extended registers.
540 static unsigned DetermineREXPrefix(const MCInst &MI, uint64_t TSFlags,
541 const TargetInstrDesc &Desc) {
543 if (TSFlags & X86II::REX_W)
544 REX |= 1 << 3; // set REX.W
546 if (MI.getNumOperands() == 0) return REX;
548 unsigned NumOps = MI.getNumOperands();
549 // FIXME: MCInst should explicitize the two-addrness.
550 bool isTwoAddr = NumOps > 1 &&
551 Desc.getOperandConstraint(1, TOI::TIED_TO) != -1;
553 // If it accesses SPL, BPL, SIL, or DIL, then it requires a 0x40 REX prefix.
554 unsigned i = isTwoAddr ? 1 : 0;
555 for (; i != NumOps; ++i) {
556 const MCOperand &MO = MI.getOperand(i);
557 if (!MO.isReg()) continue;
558 unsigned Reg = MO.getReg();
559 if (!X86InstrInfo::isX86_64NonExtLowByteReg(Reg)) continue;
560 // FIXME: The caller of DetermineREXPrefix slaps this prefix onto anything
561 // that returns non-zero.
562 REX |= 0x40; // REX fixed encoding prefix
566 switch (TSFlags & X86II::FormMask) {
567 case X86II::MRMInitReg: assert(0 && "FIXME: Remove this!");
568 case X86II::MRMSrcReg:
569 if (MI.getOperand(0).isReg() &&
570 X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(0).getReg()))
571 REX |= 1 << 2; // set REX.R
572 i = isTwoAddr ? 2 : 1;
573 for (; i != NumOps; ++i) {
574 const MCOperand &MO = MI.getOperand(i);
575 if (MO.isReg() && X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
576 REX |= 1 << 0; // set REX.B
579 case X86II::MRMSrcMem: {
580 if (MI.getOperand(0).isReg() &&
581 X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(0).getReg()))
582 REX |= 1 << 2; // set REX.R
584 i = isTwoAddr ? 2 : 1;
585 for (; i != NumOps; ++i) {
586 const MCOperand &MO = MI.getOperand(i);
588 if (X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
589 REX |= 1 << Bit; // set REX.B (Bit=0) and REX.X (Bit=1)
595 case X86II::MRM0m: case X86II::MRM1m:
596 case X86II::MRM2m: case X86II::MRM3m:
597 case X86II::MRM4m: case X86II::MRM5m:
598 case X86II::MRM6m: case X86II::MRM7m:
599 case X86II::MRMDestMem: {
600 unsigned e = (isTwoAddr ? X86::AddrNumOperands+1 : X86::AddrNumOperands);
601 i = isTwoAddr ? 1 : 0;
602 if (NumOps > e && MI.getOperand(e).isReg() &&
603 X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(e).getReg()))
604 REX |= 1 << 2; // set REX.R
606 for (; i != e; ++i) {
607 const MCOperand &MO = MI.getOperand(i);
609 if (X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
610 REX |= 1 << Bit; // REX.B (Bit=0) and REX.X (Bit=1)
617 if (MI.getOperand(0).isReg() &&
618 X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(0).getReg()))
619 REX |= 1 << 0; // set REX.B
620 i = isTwoAddr ? 2 : 1;
621 for (unsigned e = NumOps; i != e; ++i) {
622 const MCOperand &MO = MI.getOperand(i);
623 if (MO.isReg() && X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
624 REX |= 1 << 2; // set REX.R
631 /// EmitOpcodePrefix - Emit all instruction prefixes prior to the opcode.
633 /// MemOperand is the operand # of the start of a memory operand if present. If
634 /// Not present, it is -1.
635 void X86MCCodeEmitter::EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
636 int MemOperand, const MCInst &MI,
637 const TargetInstrDesc &Desc,
638 raw_ostream &OS) const {
640 // Emit the lock opcode prefix as needed.
641 if (TSFlags & X86II::LOCK)
642 EmitByte(0xF0, CurByte, OS);
644 // Emit segment override opcode prefix as needed.
645 switch (TSFlags & X86II::SegOvrMask) {
646 default: assert(0 && "Invalid segment!");
648 // No segment override, check for explicit one on memory operand.
649 if (MemOperand != -1) { // If the instruction has a memory operand.
650 switch (MI.getOperand(MemOperand+X86::AddrSegmentReg).getReg()) {
651 default: assert(0 && "Unknown segment register!");
653 case X86::CS: EmitByte(0x2E, CurByte, OS); break;
654 case X86::SS: EmitByte(0x36, CurByte, OS); break;
655 case X86::DS: EmitByte(0x3E, CurByte, OS); break;
656 case X86::ES: EmitByte(0x26, CurByte, OS); break;
657 case X86::FS: EmitByte(0x64, CurByte, OS); break;
658 case X86::GS: EmitByte(0x65, CurByte, OS); break;
663 EmitByte(0x64, CurByte, OS);
666 EmitByte(0x65, CurByte, OS);
670 // Emit the repeat opcode prefix as needed.
671 if ((TSFlags & X86II::Op0Mask) == X86II::REP)
672 EmitByte(0xF3, CurByte, OS);
674 // Emit the operand size opcode prefix as needed.
675 if (TSFlags & X86II::OpSize)
676 EmitByte(0x66, CurByte, OS);
678 // Emit the address size opcode prefix as needed.
679 if (TSFlags & X86II::AdSize)
680 EmitByte(0x67, CurByte, OS);
682 bool Need0FPrefix = false;
683 switch (TSFlags & X86II::Op0Mask) {
684 default: assert(0 && "Invalid prefix!");
685 case 0: break; // No prefix!
686 case X86II::REP: break; // already handled.
687 case X86II::TB: // Two-byte opcode prefix
688 case X86II::T8: // 0F 38
689 case X86II::TA: // 0F 3A
692 case X86II::TF: // F2 0F 38
693 EmitByte(0xF2, CurByte, OS);
696 case X86II::XS: // F3 0F
697 EmitByte(0xF3, CurByte, OS);
700 case X86II::XD: // F2 0F
701 EmitByte(0xF2, CurByte, OS);
704 case X86II::D8: EmitByte(0xD8, CurByte, OS); break;
705 case X86II::D9: EmitByte(0xD9, CurByte, OS); break;
706 case X86II::DA: EmitByte(0xDA, CurByte, OS); break;
707 case X86II::DB: EmitByte(0xDB, CurByte, OS); break;
708 case X86II::DC: EmitByte(0xDC, CurByte, OS); break;
709 case X86II::DD: EmitByte(0xDD, CurByte, OS); break;
710 case X86II::DE: EmitByte(0xDE, CurByte, OS); break;
711 case X86II::DF: EmitByte(0xDF, CurByte, OS); break;
714 // Handle REX prefix.
715 // FIXME: Can this come before F2 etc to simplify emission?
717 if (unsigned REX = DetermineREXPrefix(MI, TSFlags, Desc))
718 EmitByte(0x40 | REX, CurByte, OS);
721 // 0x0F escape code must be emitted just before the opcode.
723 EmitByte(0x0F, CurByte, OS);
725 // FIXME: Pull this up into previous switch if REX can be moved earlier.
726 switch (TSFlags & X86II::Op0Mask) {
727 case X86II::TF: // F2 0F 38
728 case X86II::T8: // 0F 38
729 EmitByte(0x38, CurByte, OS);
731 case X86II::TA: // 0F 3A
732 EmitByte(0x3A, CurByte, OS);
737 void X86MCCodeEmitter::
738 EncodeInstruction(const MCInst &MI, raw_ostream &OS,
739 SmallVectorImpl<MCFixup> &Fixups) const {
740 unsigned Opcode = MI.getOpcode();
741 const TargetInstrDesc &Desc = TII.get(Opcode);
742 uint64_t TSFlags = Desc.TSFlags;
744 // Pseudo instructions don't get encoded.
745 if ((TSFlags & X86II::FormMask) == X86II::Pseudo)
748 // If this is a two-address instruction, skip one of the register operands.
749 // FIXME: This should be handled during MCInst lowering.
750 unsigned NumOps = Desc.getNumOperands();
752 if (NumOps > 1 && Desc.getOperandConstraint(1, TOI::TIED_TO) != -1)
754 else if (NumOps > 2 && Desc.getOperandConstraint(NumOps-1, TOI::TIED_TO)== 0)
755 // Skip the last source operand that is tied_to the dest reg. e.g. LXADD32
758 // Keep track of the current byte being emitted.
759 unsigned CurByte = 0;
761 // Is this instruction encoded using the AVX VEX prefix?
762 bool HasVEXPrefix = false;
764 // It uses the VEX.VVVV field?
765 bool HasVEX_4V = false;
767 if ((TSFlags >> 32) & X86II::VEX)
769 if ((TSFlags >> 32) & X86II::VEX_4V)
772 // Determine where the memory operand starts, if present.
773 int MemoryOperand = X86II::getMemoryOperandNo(TSFlags);
774 if (MemoryOperand != -1) MemoryOperand += CurOp;
777 EmitOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, OS);
779 // FIXME: Segment overrides??
780 EmitVEXOpcodePrefix(TSFlags, CurByte, MI, Desc, OS);
782 unsigned char BaseOpcode = X86II::getBaseOpcodeFor(TSFlags);
783 unsigned SrcRegNum = 0;
784 switch (TSFlags & X86II::FormMask) {
785 case X86II::MRMInitReg:
786 assert(0 && "FIXME: Remove this form when the JIT moves to MCCodeEmitter!");
787 default: errs() << "FORM: " << (TSFlags & X86II::FormMask) << "\n";
788 assert(0 && "Unknown FormMask value in X86MCCodeEmitter!");
790 assert(0 && "Pseudo instruction shouldn't be emitted");
792 EmitByte(BaseOpcode, CurByte, OS);
795 case X86II::AddRegFrm:
796 EmitByte(BaseOpcode + GetX86RegNum(MI.getOperand(CurOp++)), CurByte, OS);
799 case X86II::MRMDestReg:
800 EmitByte(BaseOpcode, CurByte, OS);
801 EmitRegModRMByte(MI.getOperand(CurOp),
802 GetX86RegNum(MI.getOperand(CurOp+1)), CurByte, OS);
806 case X86II::MRMDestMem:
807 EmitByte(BaseOpcode, CurByte, OS);
808 EmitMemModRMByte(MI, CurOp,
809 GetX86RegNum(MI.getOperand(CurOp + X86::AddrNumOperands)),
810 TSFlags, CurByte, OS, Fixups);
811 CurOp += X86::AddrNumOperands + 1;
814 case X86II::MRMSrcReg:
815 EmitByte(BaseOpcode, CurByte, OS);
816 SrcRegNum = CurOp + 1;
818 if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV)
821 EmitRegModRMByte(MI.getOperand(SrcRegNum),
822 GetX86RegNum(MI.getOperand(CurOp)), CurByte, OS);
823 CurOp = SrcRegNum + 1;
826 case X86II::MRMSrcMem: {
827 int AddrOperands = X86::AddrNumOperands;
828 unsigned FirstMemOp = CurOp+1;
831 ++FirstMemOp; // Skip the register source (which is encoded in VEX_VVVV).
834 EmitByte(BaseOpcode, CurByte, OS);
836 EmitMemModRMByte(MI, FirstMemOp, GetX86RegNum(MI.getOperand(CurOp)),
837 TSFlags, CurByte, OS, Fixups);
838 CurOp += AddrOperands + 1;
842 case X86II::MRM0r: case X86II::MRM1r:
843 case X86II::MRM2r: case X86II::MRM3r:
844 case X86II::MRM4r: case X86II::MRM5r:
845 case X86II::MRM6r: case X86II::MRM7r:
846 if (HasVEX_4V) // Skip the register dst (which is encoded in VEX_VVVV).
848 EmitByte(BaseOpcode, CurByte, OS);
849 EmitRegModRMByte(MI.getOperand(CurOp++),
850 (TSFlags & X86II::FormMask)-X86II::MRM0r,
853 case X86II::MRM0m: case X86II::MRM1m:
854 case X86II::MRM2m: case X86II::MRM3m:
855 case X86II::MRM4m: case X86II::MRM5m:
856 case X86II::MRM6m: case X86II::MRM7m:
857 EmitByte(BaseOpcode, CurByte, OS);
858 EmitMemModRMByte(MI, CurOp, (TSFlags & X86II::FormMask)-X86II::MRM0m,
859 TSFlags, CurByte, OS, Fixups);
860 CurOp += X86::AddrNumOperands;
863 EmitByte(BaseOpcode, CurByte, OS);
864 EmitByte(0xC1, CurByte, OS);
867 EmitByte(BaseOpcode, CurByte, OS);
868 EmitByte(0xC2, CurByte, OS);
871 EmitByte(BaseOpcode, CurByte, OS);
872 EmitByte(0xC3, CurByte, OS);
875 EmitByte(BaseOpcode, CurByte, OS);
876 EmitByte(0xC4, CurByte, OS);
879 EmitByte(BaseOpcode, CurByte, OS);
880 EmitByte(0xC8, CurByte, OS);
883 EmitByte(BaseOpcode, CurByte, OS);
884 EmitByte(0xC9, CurByte, OS);
887 EmitByte(BaseOpcode, CurByte, OS);
888 EmitByte(0xE8, CurByte, OS);
891 EmitByte(BaseOpcode, CurByte, OS);
892 EmitByte(0xF0, CurByte, OS);
895 EmitByte(BaseOpcode, CurByte, OS);
896 EmitByte(0xF8, CurByte, OS);
899 EmitByte(BaseOpcode, CurByte, OS);
900 EmitByte(0xF9, CurByte, OS);
904 // If there is a remaining operand, it must be a trailing immediate. Emit it
905 // according to the right size for the instruction.
906 if (CurOp != NumOps) {
907 // The last source register of a 4 operand instruction in AVX is encoded
908 // in bits[7:4] of a immediate byte, and bits[3:0] are ignored.
909 if ((TSFlags >> 32) & X86II::VEX_I8IMM) {
910 const MCOperand &MO = MI.getOperand(CurOp++);
912 X86InstrInfo::isX86_64ExtendedReg(MO.getReg());
913 unsigned RegNum = (IsExtReg ? (1 << 7) : 0);
914 RegNum |= GetX86RegNum(MO) << 4;
915 EmitImmediate(MCOperand::CreateImm(RegNum), 1, FK_Data_1, CurByte, OS,
918 EmitImmediate(MI.getOperand(CurOp++),
919 X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
920 CurByte, OS, Fixups);
926 if (/*!Desc.isVariadic() &&*/ CurOp != NumOps) {
927 errs() << "Cannot encode all operands of: ";