forked from OSchip/llvm-project
1500 lines
53 KiB
C++
1500 lines
53 KiB
C++
//===-- X86MCCodeEmitter.cpp - Convert X86 code to machine code -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the X86MCCodeEmitter class.
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//
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/X86MCTargetDesc.h"
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#include "MCTargetDesc/X86BaseInfo.h"
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#include "MCTargetDesc/X86FixupKinds.h"
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#include "llvm/MC/MCCodeEmitter.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/MC/MCInstrInfo.h"
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#include "llvm/MC/MCRegisterInfo.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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#define DEBUG_TYPE "mccodeemitter"
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namespace {
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class X86MCCodeEmitter : public MCCodeEmitter {
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X86MCCodeEmitter(const X86MCCodeEmitter &) = delete;
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void operator=(const X86MCCodeEmitter &) = delete;
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const MCInstrInfo &MCII;
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MCContext &Ctx;
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public:
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X86MCCodeEmitter(const MCInstrInfo &mcii, MCContext &ctx)
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: MCII(mcii), Ctx(ctx) {
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}
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~X86MCCodeEmitter() override {}
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bool is64BitMode(const MCSubtargetInfo &STI) const {
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return (STI.getFeatureBits() & X86::Mode64Bit) != 0;
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}
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bool is32BitMode(const MCSubtargetInfo &STI) const {
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return (STI.getFeatureBits() & X86::Mode32Bit) != 0;
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}
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bool is16BitMode(const MCSubtargetInfo &STI) const {
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return (STI.getFeatureBits() & X86::Mode16Bit) != 0;
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}
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/// Is16BitMemOperand - Return true if the specified instruction has
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/// a 16-bit memory operand. Op specifies the operand # of the memoperand.
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bool Is16BitMemOperand(const MCInst &MI, unsigned Op,
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const MCSubtargetInfo &STI) const {
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const MCOperand &BaseReg = MI.getOperand(Op+X86::AddrBaseReg);
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const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg);
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const MCOperand &Disp = MI.getOperand(Op+X86::AddrDisp);
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if (is16BitMode(STI) && BaseReg.getReg() == 0 &&
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Disp.isImm() && Disp.getImm() < 0x10000)
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return true;
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if ((BaseReg.getReg() != 0 &&
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X86MCRegisterClasses[X86::GR16RegClassID].contains(BaseReg.getReg())) ||
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(IndexReg.getReg() != 0 &&
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X86MCRegisterClasses[X86::GR16RegClassID].contains(IndexReg.getReg())))
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return true;
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return false;
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}
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unsigned GetX86RegNum(const MCOperand &MO) const {
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return Ctx.getRegisterInfo()->getEncodingValue(MO.getReg()) & 0x7;
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}
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// On regular x86, both XMM0-XMM7 and XMM8-XMM15 are encoded in the range
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// 0-7 and the difference between the 2 groups is given by the REX prefix.
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// In the VEX prefix, registers are seen sequencially from 0-15 and encoded
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// in 1's complement form, example:
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//
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// ModRM field => XMM9 => 1
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// VEX.VVVV => XMM9 => ~9
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//
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// See table 4-35 of Intel AVX Programming Reference for details.
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unsigned char getVEXRegisterEncoding(const MCInst &MI,
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unsigned OpNum) const {
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unsigned SrcReg = MI.getOperand(OpNum).getReg();
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unsigned SrcRegNum = GetX86RegNum(MI.getOperand(OpNum));
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if (X86II::isX86_64ExtendedReg(SrcReg))
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SrcRegNum |= 8;
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// The registers represented through VEX_VVVV should
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// be encoded in 1's complement form.
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return (~SrcRegNum) & 0xf;
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}
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unsigned char getWriteMaskRegisterEncoding(const MCInst &MI,
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unsigned OpNum) const {
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assert(X86::K0 != MI.getOperand(OpNum).getReg() &&
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"Invalid mask register as write-mask!");
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unsigned MaskRegNum = GetX86RegNum(MI.getOperand(OpNum));
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return MaskRegNum;
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}
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void EmitByte(unsigned char C, unsigned &CurByte, raw_ostream &OS) const {
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OS << (char)C;
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++CurByte;
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}
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void EmitConstant(uint64_t Val, unsigned Size, unsigned &CurByte,
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raw_ostream &OS) const {
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// Output the constant in little endian byte order.
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for (unsigned i = 0; i != Size; ++i) {
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EmitByte(Val & 255, CurByte, OS);
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Val >>= 8;
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}
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}
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void EmitImmediate(const MCOperand &Disp, SMLoc Loc,
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unsigned ImmSize, MCFixupKind FixupKind,
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unsigned &CurByte, raw_ostream &OS,
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SmallVectorImpl<MCFixup> &Fixups,
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int ImmOffset = 0) const;
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inline static unsigned char ModRMByte(unsigned Mod, unsigned RegOpcode,
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unsigned RM) {
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assert(Mod < 4 && RegOpcode < 8 && RM < 8 && "ModRM Fields out of range!");
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return RM | (RegOpcode << 3) | (Mod << 6);
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}
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void EmitRegModRMByte(const MCOperand &ModRMReg, unsigned RegOpcodeFld,
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unsigned &CurByte, raw_ostream &OS) const {
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EmitByte(ModRMByte(3, RegOpcodeFld, GetX86RegNum(ModRMReg)), CurByte, OS);
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}
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void EmitSIBByte(unsigned SS, unsigned Index, unsigned Base,
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unsigned &CurByte, raw_ostream &OS) const {
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// SIB byte is in the same format as the ModRMByte.
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EmitByte(ModRMByte(SS, Index, Base), CurByte, OS);
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}
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void EmitMemModRMByte(const MCInst &MI, unsigned Op,
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unsigned RegOpcodeField,
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uint64_t TSFlags, unsigned &CurByte, raw_ostream &OS,
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SmallVectorImpl<MCFixup> &Fixups,
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const MCSubtargetInfo &STI) const;
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void encodeInstruction(const MCInst &MI, raw_ostream &OS,
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SmallVectorImpl<MCFixup> &Fixups,
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const MCSubtargetInfo &STI) const override;
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void EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand,
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const MCInst &MI, const MCInstrDesc &Desc,
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raw_ostream &OS) const;
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void EmitSegmentOverridePrefix(unsigned &CurByte, unsigned SegOperand,
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const MCInst &MI, raw_ostream &OS) const;
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void EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand,
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const MCInst &MI, const MCInstrDesc &Desc,
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const MCSubtargetInfo &STI,
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raw_ostream &OS) const;
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};
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} // end anonymous namespace
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MCCodeEmitter *llvm::createX86MCCodeEmitter(const MCInstrInfo &MCII,
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const MCRegisterInfo &MRI,
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MCContext &Ctx) {
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return new X86MCCodeEmitter(MCII, Ctx);
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}
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/// isDisp8 - Return true if this signed displacement fits in a 8-bit
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/// sign-extended field.
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static bool isDisp8(int Value) {
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return Value == (signed char)Value;
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}
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/// isCDisp8 - Return true if this signed displacement fits in a 8-bit
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/// compressed dispacement field.
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static bool isCDisp8(uint64_t TSFlags, int Value, int& CValue) {
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assert(((TSFlags & X86II::EncodingMask) == X86II::EVEX) &&
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"Compressed 8-bit displacement is only valid for EVEX inst.");
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unsigned CD8_Scale =
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(TSFlags & X86II::CD8_Scale_Mask) >> X86II::CD8_Scale_Shift;
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if (CD8_Scale == 0) {
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CValue = Value;
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return isDisp8(Value);
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}
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unsigned Mask = CD8_Scale - 1;
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assert((CD8_Scale & Mask) == 0 && "Invalid memory object size.");
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if (Value & Mask) // Unaligned offset
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return false;
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Value /= (int)CD8_Scale;
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bool Ret = (Value == (signed char)Value);
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if (Ret)
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CValue = Value;
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return Ret;
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}
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/// getImmFixupKind - Return the appropriate fixup kind to use for an immediate
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/// in an instruction with the specified TSFlags.
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static MCFixupKind getImmFixupKind(uint64_t TSFlags) {
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unsigned Size = X86II::getSizeOfImm(TSFlags);
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bool isPCRel = X86II::isImmPCRel(TSFlags);
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if (X86II::isImmSigned(TSFlags)) {
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switch (Size) {
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default: llvm_unreachable("Unsupported signed fixup size!");
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case 4: return MCFixupKind(X86::reloc_signed_4byte);
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}
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}
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return MCFixup::getKindForSize(Size, isPCRel);
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}
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/// Is32BitMemOperand - Return true if the specified instruction has
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/// a 32-bit memory operand. Op specifies the operand # of the memoperand.
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static bool Is32BitMemOperand(const MCInst &MI, unsigned Op) {
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const MCOperand &BaseReg = MI.getOperand(Op+X86::AddrBaseReg);
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const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg);
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if ((BaseReg.getReg() != 0 &&
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X86MCRegisterClasses[X86::GR32RegClassID].contains(BaseReg.getReg())) ||
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(IndexReg.getReg() != 0 &&
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X86MCRegisterClasses[X86::GR32RegClassID].contains(IndexReg.getReg())))
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return true;
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return false;
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}
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/// Is64BitMemOperand - Return true if the specified instruction has
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/// a 64-bit memory operand. Op specifies the operand # of the memoperand.
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#ifndef NDEBUG
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static bool Is64BitMemOperand(const MCInst &MI, unsigned Op) {
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const MCOperand &BaseReg = MI.getOperand(Op+X86::AddrBaseReg);
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const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg);
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if ((BaseReg.getReg() != 0 &&
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X86MCRegisterClasses[X86::GR64RegClassID].contains(BaseReg.getReg())) ||
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(IndexReg.getReg() != 0 &&
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X86MCRegisterClasses[X86::GR64RegClassID].contains(IndexReg.getReg())))
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return true;
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return false;
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}
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#endif
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/// StartsWithGlobalOffsetTable - Check if this expression starts with
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/// _GLOBAL_OFFSET_TABLE_ and if it is of the form
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/// _GLOBAL_OFFSET_TABLE_-symbol. This is needed to support PIC on ELF
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/// i386 as _GLOBAL_OFFSET_TABLE_ is magical. We check only simple case that
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/// are know to be used: _GLOBAL_OFFSET_TABLE_ by itself or at the start
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/// of a binary expression.
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enum GlobalOffsetTableExprKind {
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GOT_None,
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GOT_Normal,
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GOT_SymDiff
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};
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static GlobalOffsetTableExprKind
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StartsWithGlobalOffsetTable(const MCExpr *Expr) {
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const MCExpr *RHS = nullptr;
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if (Expr->getKind() == MCExpr::Binary) {
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const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(Expr);
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Expr = BE->getLHS();
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RHS = BE->getRHS();
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}
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if (Expr->getKind() != MCExpr::SymbolRef)
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return GOT_None;
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const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Expr);
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const MCSymbol &S = Ref->getSymbol();
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if (S.getName() != "_GLOBAL_OFFSET_TABLE_")
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return GOT_None;
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if (RHS && RHS->getKind() == MCExpr::SymbolRef)
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return GOT_SymDiff;
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return GOT_Normal;
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}
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static bool HasSecRelSymbolRef(const MCExpr *Expr) {
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if (Expr->getKind() == MCExpr::SymbolRef) {
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const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Expr);
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return Ref->getKind() == MCSymbolRefExpr::VK_SECREL;
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}
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return false;
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}
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void X86MCCodeEmitter::
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EmitImmediate(const MCOperand &DispOp, SMLoc Loc, unsigned Size,
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MCFixupKind FixupKind, unsigned &CurByte, raw_ostream &OS,
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SmallVectorImpl<MCFixup> &Fixups, int ImmOffset) const {
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const MCExpr *Expr = nullptr;
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if (DispOp.isImm()) {
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// If this is a simple integer displacement that doesn't require a
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// relocation, emit it now.
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if (FixupKind != FK_PCRel_1 &&
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FixupKind != FK_PCRel_2 &&
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FixupKind != FK_PCRel_4) {
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EmitConstant(DispOp.getImm()+ImmOffset, Size, CurByte, OS);
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return;
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}
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Expr = MCConstantExpr::Create(DispOp.getImm(), Ctx);
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} else {
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Expr = DispOp.getExpr();
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}
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// If we have an immoffset, add it to the expression.
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if ((FixupKind == FK_Data_4 ||
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FixupKind == FK_Data_8 ||
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FixupKind == MCFixupKind(X86::reloc_signed_4byte))) {
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GlobalOffsetTableExprKind Kind = StartsWithGlobalOffsetTable(Expr);
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if (Kind != GOT_None) {
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assert(ImmOffset == 0);
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if (Size == 8) {
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FixupKind = MCFixupKind(X86::reloc_global_offset_table8);
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} else {
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assert(Size == 4);
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FixupKind = MCFixupKind(X86::reloc_global_offset_table);
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}
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if (Kind == GOT_Normal)
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ImmOffset = CurByte;
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} else if (Expr->getKind() == MCExpr::SymbolRef) {
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if (HasSecRelSymbolRef(Expr)) {
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FixupKind = MCFixupKind(FK_SecRel_4);
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}
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} else if (Expr->getKind() == MCExpr::Binary) {
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const MCBinaryExpr *Bin = static_cast<const MCBinaryExpr*>(Expr);
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if (HasSecRelSymbolRef(Bin->getLHS())
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|| HasSecRelSymbolRef(Bin->getRHS())) {
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FixupKind = MCFixupKind(FK_SecRel_4);
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}
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}
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}
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// If the fixup is pc-relative, we need to bias the value to be relative to
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// the start of the field, not the end of the field.
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if (FixupKind == FK_PCRel_4 ||
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FixupKind == MCFixupKind(X86::reloc_riprel_4byte) ||
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FixupKind == MCFixupKind(X86::reloc_riprel_4byte_movq_load))
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ImmOffset -= 4;
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if (FixupKind == FK_PCRel_2)
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ImmOffset -= 2;
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if (FixupKind == FK_PCRel_1)
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ImmOffset -= 1;
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if (ImmOffset)
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Expr = MCBinaryExpr::CreateAdd(Expr, MCConstantExpr::Create(ImmOffset, Ctx),
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Ctx);
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// Emit a symbolic constant as a fixup and 4 zeros.
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Fixups.push_back(MCFixup::create(CurByte, Expr, FixupKind, Loc));
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EmitConstant(0, Size, CurByte, OS);
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}
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void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
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unsigned RegOpcodeField,
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uint64_t TSFlags, unsigned &CurByte,
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raw_ostream &OS,
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SmallVectorImpl<MCFixup> &Fixups,
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const MCSubtargetInfo &STI) const{
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const MCOperand &Disp = MI.getOperand(Op+X86::AddrDisp);
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const MCOperand &Base = MI.getOperand(Op+X86::AddrBaseReg);
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const MCOperand &Scale = MI.getOperand(Op+X86::AddrScaleAmt);
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const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg);
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unsigned BaseReg = Base.getReg();
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bool HasEVEX = (TSFlags & X86II::EncodingMask) == X86II::EVEX;
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// Handle %rip relative addressing.
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if (BaseReg == X86::RIP) { // [disp32+RIP] in X86-64 mode
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assert(is64BitMode(STI) && "Rip-relative addressing requires 64-bit mode");
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assert(IndexReg.getReg() == 0 && "Invalid rip-relative address");
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EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS);
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unsigned FixupKind = X86::reloc_riprel_4byte;
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// movq loads are handled with a special relocation form which allows the
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// linker to eliminate some loads for GOT references which end up in the
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// same linkage unit.
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if (MI.getOpcode() == X86::MOV64rm)
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FixupKind = X86::reloc_riprel_4byte_movq_load;
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// rip-relative addressing is actually relative to the *next* instruction.
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// Since an immediate can follow the mod/rm byte for an instruction, this
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// means that we need to bias the immediate field of the instruction with
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// the size of the immediate field. If we have this case, add it into the
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// expression to emit.
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int ImmSize = X86II::hasImm(TSFlags) ? X86II::getSizeOfImm(TSFlags) : 0;
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EmitImmediate(Disp, MI.getLoc(), 4, MCFixupKind(FixupKind),
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CurByte, OS, Fixups, -ImmSize);
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return;
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}
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unsigned BaseRegNo = BaseReg ? GetX86RegNum(Base) : -1U;
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// 16-bit addressing forms of the ModR/M byte have a different encoding for
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// the R/M field and are far more limited in which registers can be used.
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if (Is16BitMemOperand(MI, Op, STI)) {
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if (BaseReg) {
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// For 32-bit addressing, the row and column values in Table 2-2 are
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// basically the same. It's AX/CX/DX/BX/SP/BP/SI/DI in that order, with
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// some special cases. And GetX86RegNum reflects that numbering.
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// For 16-bit addressing it's more fun, as shown in the SDM Vol 2A,
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// Table 2-1 "16-Bit Addressing Forms with the ModR/M byte". We can only
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// use SI/DI/BP/BX, which have "row" values 4-7 in no particular order,
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// while values 0-3 indicate the allowed combinations (base+index) of
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// those: 0 for BX+SI, 1 for BX+DI, 2 for BP+SI, 3 for BP+DI.
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//
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// R16Table[] is a lookup from the normal RegNo, to the row values from
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// Table 2-1 for 16-bit addressing modes. Where zero means disallowed.
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static const unsigned R16Table[] = { 0, 0, 0, 7, 0, 6, 4, 5 };
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unsigned RMfield = R16Table[BaseRegNo];
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assert(RMfield && "invalid 16-bit base register");
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if (IndexReg.getReg()) {
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unsigned IndexReg16 = R16Table[GetX86RegNum(IndexReg)];
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assert(IndexReg16 && "invalid 16-bit index register");
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// We must have one of SI/DI (4,5), and one of BP/BX (6,7).
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assert(((IndexReg16 ^ RMfield) & 2) &&
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"invalid 16-bit base/index register combination");
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assert(Scale.getImm() == 1 &&
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"invalid scale for 16-bit memory reference");
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// Allow base/index to appear in either order (although GAS doesn't).
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if (IndexReg16 & 2)
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RMfield = (RMfield & 1) | ((7 - IndexReg16) << 1);
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else
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RMfield = (IndexReg16 & 1) | ((7 - RMfield) << 1);
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}
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if (Disp.isImm() && isDisp8(Disp.getImm())) {
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if (Disp.getImm() == 0 && BaseRegNo != N86::EBP) {
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// There is no displacement; just the register.
|
|
EmitByte(ModRMByte(0, RegOpcodeField, RMfield), CurByte, OS);
|
|
return;
|
|
}
|
|
// Use the [REG]+disp8 form, including for [BP] which cannot be encoded.
|
|
EmitByte(ModRMByte(1, RegOpcodeField, RMfield), CurByte, OS);
|
|
EmitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups);
|
|
return;
|
|
}
|
|
// This is the [REG]+disp16 case.
|
|
EmitByte(ModRMByte(2, RegOpcodeField, RMfield), CurByte, OS);
|
|
} else {
|
|
// There is no BaseReg; this is the plain [disp16] case.
|
|
EmitByte(ModRMByte(0, RegOpcodeField, 6), CurByte, OS);
|
|
}
|
|
|
|
// Emit 16-bit displacement for plain disp16 or [REG]+disp16 cases.
|
|
EmitImmediate(Disp, MI.getLoc(), 2, FK_Data_2, CurByte, OS, Fixups);
|
|
return;
|
|
}
|
|
|
|
// Determine whether a SIB byte is needed.
|
|
// If no BaseReg, issue a RIP relative instruction only if the MCE can
|
|
// resolve addresses on-the-fly, otherwise use SIB (Intel Manual 2A, table
|
|
// 2-7) and absolute references.
|
|
|
|
if (// The SIB byte must be used if there is an index register.
|
|
IndexReg.getReg() == 0 &&
|
|
// The SIB byte must be used if the base is ESP/RSP/R12, all of which
|
|
// encode to an R/M value of 4, which indicates that a SIB byte is
|
|
// present.
|
|
BaseRegNo != N86::ESP &&
|
|
// If there is no base register and we're in 64-bit mode, we need a SIB
|
|
// byte to emit an addr that is just 'disp32' (the non-RIP relative form).
|
|
(!is64BitMode(STI) || BaseReg != 0)) {
|
|
|
|
if (BaseReg == 0) { // [disp32] in X86-32 mode
|
|
EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS);
|
|
EmitImmediate(Disp, MI.getLoc(), 4, FK_Data_4, CurByte, OS, Fixups);
|
|
return;
|
|
}
|
|
|
|
// If the base is not EBP/ESP and there is no displacement, use simple
|
|
// indirect register encoding, this handles addresses like [EAX]. The
|
|
// encoding for [EBP] with no displacement means [disp32] so we handle it
|
|
// by emitting a displacement of 0 below.
|
|
if (Disp.isImm() && Disp.getImm() == 0 && BaseRegNo != N86::EBP) {
|
|
EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS);
|
|
return;
|
|
}
|
|
|
|
// Otherwise, if the displacement fits in a byte, encode as [REG+disp8].
|
|
if (Disp.isImm()) {
|
|
if (!HasEVEX && isDisp8(Disp.getImm())) {
|
|
EmitByte(ModRMByte(1, RegOpcodeField, BaseRegNo), CurByte, OS);
|
|
EmitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups);
|
|
return;
|
|
}
|
|
// Try EVEX compressed 8-bit displacement first; if failed, fall back to
|
|
// 32-bit displacement.
|
|
int CDisp8 = 0;
|
|
if (HasEVEX && isCDisp8(TSFlags, Disp.getImm(), CDisp8)) {
|
|
EmitByte(ModRMByte(1, RegOpcodeField, BaseRegNo), CurByte, OS);
|
|
EmitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups,
|
|
CDisp8 - Disp.getImm());
|
|
return;
|
|
}
|
|
}
|
|
|
|
// Otherwise, emit the most general non-SIB encoding: [REG+disp32]
|
|
EmitByte(ModRMByte(2, RegOpcodeField, BaseRegNo), CurByte, OS);
|
|
EmitImmediate(Disp, MI.getLoc(), 4, MCFixupKind(X86::reloc_signed_4byte), CurByte, OS,
|
|
Fixups);
|
|
return;
|
|
}
|
|
|
|
// We need a SIB byte, so start by outputting the ModR/M byte first
|
|
assert(IndexReg.getReg() != X86::ESP &&
|
|
IndexReg.getReg() != X86::RSP && "Cannot use ESP as index reg!");
|
|
|
|
bool ForceDisp32 = false;
|
|
bool ForceDisp8 = false;
|
|
int CDisp8 = 0;
|
|
int ImmOffset = 0;
|
|
if (BaseReg == 0) {
|
|
// If there is no base register, we emit the special case SIB byte with
|
|
// MOD=0, BASE=5, to JUST get the index, scale, and displacement.
|
|
EmitByte(ModRMByte(0, RegOpcodeField, 4), CurByte, OS);
|
|
ForceDisp32 = true;
|
|
} else if (!Disp.isImm()) {
|
|
// Emit the normal disp32 encoding.
|
|
EmitByte(ModRMByte(2, RegOpcodeField, 4), CurByte, OS);
|
|
ForceDisp32 = true;
|
|
} else if (Disp.getImm() == 0 &&
|
|
// Base reg can't be anything that ends up with '5' as the base
|
|
// reg, it is the magic [*] nomenclature that indicates no base.
|
|
BaseRegNo != N86::EBP) {
|
|
// Emit no displacement ModR/M byte
|
|
EmitByte(ModRMByte(0, RegOpcodeField, 4), CurByte, OS);
|
|
} else if (!HasEVEX && isDisp8(Disp.getImm())) {
|
|
// Emit the disp8 encoding.
|
|
EmitByte(ModRMByte(1, RegOpcodeField, 4), CurByte, OS);
|
|
ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
|
|
} else if (HasEVEX && isCDisp8(TSFlags, Disp.getImm(), CDisp8)) {
|
|
// Emit the disp8 encoding.
|
|
EmitByte(ModRMByte(1, RegOpcodeField, 4), CurByte, OS);
|
|
ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
|
|
ImmOffset = CDisp8 - Disp.getImm();
|
|
} else {
|
|
// Emit the normal disp32 encoding.
|
|
EmitByte(ModRMByte(2, RegOpcodeField, 4), CurByte, OS);
|
|
}
|
|
|
|
// Calculate what the SS field value should be...
|
|
static const unsigned SSTable[] = { ~0U, 0, 1, ~0U, 2, ~0U, ~0U, ~0U, 3 };
|
|
unsigned SS = SSTable[Scale.getImm()];
|
|
|
|
if (BaseReg == 0) {
|
|
// Handle the SIB byte for the case where there is no base, see Intel
|
|
// Manual 2A, table 2-7. The displacement has already been output.
|
|
unsigned IndexRegNo;
|
|
if (IndexReg.getReg())
|
|
IndexRegNo = GetX86RegNum(IndexReg);
|
|
else // Examples: [ESP+1*<noreg>+4] or [scaled idx]+disp32 (MOD=0,BASE=5)
|
|
IndexRegNo = 4;
|
|
EmitSIBByte(SS, IndexRegNo, 5, CurByte, OS);
|
|
} else {
|
|
unsigned IndexRegNo;
|
|
if (IndexReg.getReg())
|
|
IndexRegNo = GetX86RegNum(IndexReg);
|
|
else
|
|
IndexRegNo = 4; // For example [ESP+1*<noreg>+4]
|
|
EmitSIBByte(SS, IndexRegNo, GetX86RegNum(Base), CurByte, OS);
|
|
}
|
|
|
|
// Do we need to output a displacement?
|
|
if (ForceDisp8)
|
|
EmitImmediate(Disp, MI.getLoc(), 1, FK_Data_1, CurByte, OS, Fixups, ImmOffset);
|
|
else if (ForceDisp32 || Disp.getImm() != 0)
|
|
EmitImmediate(Disp, MI.getLoc(), 4, MCFixupKind(X86::reloc_signed_4byte),
|
|
CurByte, OS, Fixups);
|
|
}
|
|
|
|
/// EmitVEXOpcodePrefix - AVX instructions are encoded using a opcode prefix
|
|
/// called VEX.
|
|
void X86MCCodeEmitter::EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
|
|
int MemOperand, const MCInst &MI,
|
|
const MCInstrDesc &Desc,
|
|
raw_ostream &OS) const {
|
|
assert(!(TSFlags & X86II::LOCK) && "Can't have LOCK VEX.");
|
|
|
|
uint64_t Encoding = TSFlags & X86II::EncodingMask;
|
|
bool HasEVEX_K = TSFlags & X86II::EVEX_K;
|
|
bool HasVEX_4V = TSFlags & X86II::VEX_4V;
|
|
bool HasVEX_4VOp3 = TSFlags & X86II::VEX_4VOp3;
|
|
bool HasMemOp4 = TSFlags & X86II::MemOp4;
|
|
bool HasEVEX_RC = TSFlags & X86II::EVEX_RC;
|
|
|
|
// VEX_R: opcode externsion equivalent to REX.R in
|
|
// 1's complement (inverted) form
|
|
//
|
|
// 1: Same as REX_R=0 (must be 1 in 32-bit mode)
|
|
// 0: Same as REX_R=1 (64 bit mode only)
|
|
//
|
|
unsigned char VEX_R = 0x1;
|
|
unsigned char EVEX_R2 = 0x1;
|
|
|
|
// VEX_X: equivalent to REX.X, only used when a
|
|
// register is used for index in SIB Byte.
|
|
//
|
|
// 1: Same as REX.X=0 (must be 1 in 32-bit mode)
|
|
// 0: Same as REX.X=1 (64-bit mode only)
|
|
unsigned char VEX_X = 0x1;
|
|
|
|
// VEX_B:
|
|
//
|
|
// 1: Same as REX_B=0 (ignored in 32-bit mode)
|
|
// 0: Same as REX_B=1 (64 bit mode only)
|
|
//
|
|
unsigned char VEX_B = 0x1;
|
|
|
|
// VEX_W: opcode specific (use like REX.W, or used for
|
|
// opcode extension, or ignored, depending on the opcode byte)
|
|
unsigned char VEX_W = 0;
|
|
|
|
// VEX_5M (VEX m-mmmmm field):
|
|
//
|
|
// 0b00000: Reserved for future use
|
|
// 0b00001: implied 0F leading opcode
|
|
// 0b00010: implied 0F 38 leading opcode bytes
|
|
// 0b00011: implied 0F 3A leading opcode bytes
|
|
// 0b00100-0b11111: Reserved for future use
|
|
// 0b01000: XOP map select - 08h instructions with imm byte
|
|
// 0b01001: XOP map select - 09h instructions with no imm byte
|
|
// 0b01010: XOP map select - 0Ah instructions with imm dword
|
|
unsigned char VEX_5M = 0;
|
|
|
|
// VEX_4V (VEX vvvv field): a register specifier
|
|
// (in 1's complement form) or 1111 if unused.
|
|
unsigned char VEX_4V = 0xf;
|
|
unsigned char EVEX_V2 = 0x1;
|
|
|
|
// VEX_L (Vector Length):
|
|
//
|
|
// 0: scalar or 128-bit vector
|
|
// 1: 256-bit vector
|
|
//
|
|
unsigned char VEX_L = 0;
|
|
unsigned char EVEX_L2 = 0;
|
|
|
|
// VEX_PP: opcode extension providing equivalent
|
|
// functionality of a SIMD prefix
|
|
//
|
|
// 0b00: None
|
|
// 0b01: 66
|
|
// 0b10: F3
|
|
// 0b11: F2
|
|
//
|
|
unsigned char VEX_PP = 0;
|
|
|
|
// EVEX_U
|
|
unsigned char EVEX_U = 1; // Always '1' so far
|
|
|
|
// EVEX_z
|
|
unsigned char EVEX_z = 0;
|
|
|
|
// EVEX_b
|
|
unsigned char EVEX_b = 0;
|
|
|
|
// EVEX_rc
|
|
unsigned char EVEX_rc = 0;
|
|
|
|
// EVEX_aaa
|
|
unsigned char EVEX_aaa = 0;
|
|
|
|
bool EncodeRC = false;
|
|
|
|
if (TSFlags & X86II::VEX_W)
|
|
VEX_W = 1;
|
|
|
|
if (TSFlags & X86II::VEX_L)
|
|
VEX_L = 1;
|
|
if (TSFlags & X86II::EVEX_L2)
|
|
EVEX_L2 = 1;
|
|
|
|
if (HasEVEX_K && (TSFlags & X86II::EVEX_Z))
|
|
EVEX_z = 1;
|
|
|
|
if ((TSFlags & X86II::EVEX_B))
|
|
EVEX_b = 1;
|
|
|
|
switch (TSFlags & X86II::OpPrefixMask) {
|
|
default: break; // VEX_PP already correct
|
|
case X86II::PD: VEX_PP = 0x1; break; // 66
|
|
case X86II::XS: VEX_PP = 0x2; break; // F3
|
|
case X86II::XD: VEX_PP = 0x3; break; // F2
|
|
}
|
|
|
|
switch (TSFlags & X86II::OpMapMask) {
|
|
default: llvm_unreachable("Invalid prefix!");
|
|
case X86II::TB: VEX_5M = 0x1; break; // 0F
|
|
case X86II::T8: VEX_5M = 0x2; break; // 0F 38
|
|
case X86II::TA: VEX_5M = 0x3; break; // 0F 3A
|
|
case X86II::XOP8: VEX_5M = 0x8; break;
|
|
case X86II::XOP9: VEX_5M = 0x9; break;
|
|
case X86II::XOPA: VEX_5M = 0xA; break;
|
|
}
|
|
|
|
// Classify VEX_B, VEX_4V, VEX_R, VEX_X
|
|
unsigned NumOps = Desc.getNumOperands();
|
|
unsigned CurOp = X86II::getOperandBias(Desc);
|
|
|
|
switch (TSFlags & X86II::FormMask) {
|
|
default: llvm_unreachable("Unexpected form in EmitVEXOpcodePrefix!");
|
|
case X86II::RawFrm:
|
|
break;
|
|
case X86II::MRMDestMem: {
|
|
// MRMDestMem instructions forms:
|
|
// MemAddr, src1(ModR/M)
|
|
// MemAddr, src1(VEX_4V), src2(ModR/M)
|
|
// MemAddr, src1(ModR/M), imm8
|
|
//
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(MemOperand +
|
|
X86::AddrBaseReg).getReg()))
|
|
VEX_B = 0x0;
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(MemOperand +
|
|
X86::AddrIndexReg).getReg()))
|
|
VEX_X = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(MemOperand +
|
|
X86::AddrIndexReg).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
|
|
CurOp += X86::AddrNumOperands;
|
|
|
|
if (HasEVEX_K)
|
|
EVEX_aaa = getWriteMaskRegisterEncoding(MI, CurOp++);
|
|
|
|
if (HasVEX_4V) {
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp);
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
CurOp++;
|
|
}
|
|
|
|
const MCOperand &MO = MI.getOperand(CurOp);
|
|
if (MO.isReg()) {
|
|
if (X86II::isX86_64ExtendedReg(MO.getReg()))
|
|
VEX_R = 0x0;
|
|
if (X86II::is32ExtendedReg(MO.getReg()))
|
|
EVEX_R2 = 0x0;
|
|
}
|
|
break;
|
|
}
|
|
case X86II::MRMSrcMem:
|
|
// MRMSrcMem instructions forms:
|
|
// src1(ModR/M), MemAddr
|
|
// src1(ModR/M), src2(VEX_4V), MemAddr
|
|
// src1(ModR/M), MemAddr, imm8
|
|
// src1(ModR/M), MemAddr, src2(VEX_I8IMM)
|
|
//
|
|
// FMA4:
|
|
// dst(ModR/M.reg), src1(VEX_4V), src2(ModR/M), src3(VEX_I8IMM)
|
|
// dst(ModR/M.reg), src1(VEX_4V), src2(VEX_I8IMM), src3(ModR/M),
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_R = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_R2 = 0x0;
|
|
CurOp++;
|
|
|
|
if (HasEVEX_K)
|
|
EVEX_aaa = getWriteMaskRegisterEncoding(MI, CurOp++);
|
|
|
|
if (HasVEX_4V) {
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp);
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
CurOp++;
|
|
}
|
|
|
|
if (X86II::isX86_64ExtendedReg(
|
|
MI.getOperand(MemOperand+X86::AddrBaseReg).getReg()))
|
|
VEX_B = 0x0;
|
|
if (X86II::isX86_64ExtendedReg(
|
|
MI.getOperand(MemOperand+X86::AddrIndexReg).getReg()))
|
|
VEX_X = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(MemOperand +
|
|
X86::AddrIndexReg).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
|
|
if (HasVEX_4VOp3)
|
|
// Instruction format for 4VOp3:
|
|
// src1(ModR/M), MemAddr, src3(VEX_4V)
|
|
// CurOp points to start of the MemoryOperand,
|
|
// it skips TIED_TO operands if exist, then increments past src1.
|
|
// CurOp + X86::AddrNumOperands will point to src3.
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp+X86::AddrNumOperands);
|
|
break;
|
|
case X86II::MRM0m: case X86II::MRM1m:
|
|
case X86II::MRM2m: case X86II::MRM3m:
|
|
case X86II::MRM4m: case X86II::MRM5m:
|
|
case X86II::MRM6m: case X86II::MRM7m: {
|
|
// MRM[0-9]m instructions forms:
|
|
// MemAddr
|
|
// src1(VEX_4V), MemAddr
|
|
if (HasVEX_4V) {
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp);
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
CurOp++;
|
|
}
|
|
|
|
if (HasEVEX_K)
|
|
EVEX_aaa = getWriteMaskRegisterEncoding(MI, CurOp++);
|
|
|
|
if (X86II::isX86_64ExtendedReg(
|
|
MI.getOperand(MemOperand+X86::AddrBaseReg).getReg()))
|
|
VEX_B = 0x0;
|
|
if (X86II::isX86_64ExtendedReg(
|
|
MI.getOperand(MemOperand+X86::AddrIndexReg).getReg()))
|
|
VEX_X = 0x0;
|
|
break;
|
|
}
|
|
case X86II::MRMSrcReg:
|
|
// MRMSrcReg instructions forms:
|
|
// dst(ModR/M), src1(VEX_4V), src2(ModR/M), src3(VEX_I8IMM)
|
|
// dst(ModR/M), src1(ModR/M)
|
|
// dst(ModR/M), src1(ModR/M), imm8
|
|
//
|
|
// FMA4:
|
|
// dst(ModR/M.reg), src1(VEX_4V), src2(ModR/M), src3(VEX_I8IMM)
|
|
// dst(ModR/M.reg), src1(VEX_4V), src2(VEX_I8IMM), src3(ModR/M),
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_R = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_R2 = 0x0;
|
|
CurOp++;
|
|
|
|
if (HasEVEX_K)
|
|
EVEX_aaa = getWriteMaskRegisterEncoding(MI, CurOp++);
|
|
|
|
if (HasVEX_4V) {
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp);
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
CurOp++;
|
|
}
|
|
|
|
if (HasMemOp4) // Skip second register source (encoded in I8IMM)
|
|
CurOp++;
|
|
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_B = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_X = 0x0;
|
|
CurOp++;
|
|
if (HasVEX_4VOp3)
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp++);
|
|
if (EVEX_b) {
|
|
if (HasEVEX_RC) {
|
|
unsigned RcOperand = NumOps-1;
|
|
assert(RcOperand >= CurOp);
|
|
EVEX_rc = MI.getOperand(RcOperand).getImm() & 0x3;
|
|
}
|
|
EncodeRC = true;
|
|
}
|
|
break;
|
|
case X86II::MRMDestReg:
|
|
// MRMDestReg instructions forms:
|
|
// dst(ModR/M), src(ModR/M)
|
|
// dst(ModR/M), src(ModR/M), imm8
|
|
// dst(ModR/M), src1(VEX_4V), src2(ModR/M)
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_B = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_X = 0x0;
|
|
CurOp++;
|
|
|
|
if (HasEVEX_K)
|
|
EVEX_aaa = getWriteMaskRegisterEncoding(MI, CurOp++);
|
|
|
|
if (HasVEX_4V) {
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp);
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
CurOp++;
|
|
}
|
|
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_R = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_R2 = 0x0;
|
|
if (EVEX_b)
|
|
EncodeRC = true;
|
|
break;
|
|
case X86II::MRM0r: case X86II::MRM1r:
|
|
case X86II::MRM2r: case X86II::MRM3r:
|
|
case X86II::MRM4r: case X86II::MRM5r:
|
|
case X86II::MRM6r: case X86II::MRM7r:
|
|
// MRM0r-MRM7r instructions forms:
|
|
// dst(VEX_4V), src(ModR/M), imm8
|
|
if (HasVEX_4V) {
|
|
VEX_4V = getVEXRegisterEncoding(MI, CurOp);
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
EVEX_V2 = 0x0;
|
|
CurOp++;
|
|
}
|
|
if (HasEVEX_K)
|
|
EVEX_aaa = getWriteMaskRegisterEncoding(MI, CurOp++);
|
|
|
|
if (X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_B = 0x0;
|
|
if (X86II::is32ExtendedReg(MI.getOperand(CurOp).getReg()))
|
|
VEX_X = 0x0;
|
|
break;
|
|
}
|
|
|
|
if (Encoding == X86II::VEX || Encoding == X86II::XOP) {
|
|
// VEX opcode prefix can have 2 or 3 bytes
|
|
//
|
|
// 3 bytes:
|
|
// +-----+ +--------------+ +-------------------+
|
|
// | C4h | | RXB | m-mmmm | | W | vvvv | L | pp |
|
|
// +-----+ +--------------+ +-------------------+
|
|
// 2 bytes:
|
|
// +-----+ +-------------------+
|
|
// | C5h | | R | vvvv | L | pp |
|
|
// +-----+ +-------------------+
|
|
//
|
|
// XOP uses a similar prefix:
|
|
// +-----+ +--------------+ +-------------------+
|
|
// | 8Fh | | RXB | m-mmmm | | W | vvvv | L | pp |
|
|
// +-----+ +--------------+ +-------------------+
|
|
unsigned char LastByte = VEX_PP | (VEX_L << 2) | (VEX_4V << 3);
|
|
|
|
// Can we use the 2 byte VEX prefix?
|
|
if (Encoding == X86II::VEX && VEX_B && VEX_X && !VEX_W && (VEX_5M == 1)) {
|
|
EmitByte(0xC5, CurByte, OS);
|
|
EmitByte(LastByte | (VEX_R << 7), CurByte, OS);
|
|
return;
|
|
}
|
|
|
|
// 3 byte VEX prefix
|
|
EmitByte(Encoding == X86II::XOP ? 0x8F : 0xC4, CurByte, OS);
|
|
EmitByte(VEX_R << 7 | VEX_X << 6 | VEX_B << 5 | VEX_5M, CurByte, OS);
|
|
EmitByte(LastByte | (VEX_W << 7), CurByte, OS);
|
|
} else {
|
|
assert(Encoding == X86II::EVEX && "unknown encoding!");
|
|
// EVEX opcode prefix can have 4 bytes
|
|
//
|
|
// +-----+ +--------------+ +-------------------+ +------------------------+
|
|
// | 62h | | RXBR' | 00mm | | W | vvvv | U | pp | | z | L'L | b | v' | aaa |
|
|
// +-----+ +--------------+ +-------------------+ +------------------------+
|
|
assert((VEX_5M & 0x3) == VEX_5M
|
|
&& "More than 2 significant bits in VEX.m-mmmm fields for EVEX!");
|
|
|
|
VEX_5M &= 0x3;
|
|
|
|
EmitByte(0x62, CurByte, OS);
|
|
EmitByte((VEX_R << 7) |
|
|
(VEX_X << 6) |
|
|
(VEX_B << 5) |
|
|
(EVEX_R2 << 4) |
|
|
VEX_5M, CurByte, OS);
|
|
EmitByte((VEX_W << 7) |
|
|
(VEX_4V << 3) |
|
|
(EVEX_U << 2) |
|
|
VEX_PP, CurByte, OS);
|
|
if (EncodeRC)
|
|
EmitByte((EVEX_z << 7) |
|
|
(EVEX_rc << 5) |
|
|
(EVEX_b << 4) |
|
|
(EVEX_V2 << 3) |
|
|
EVEX_aaa, CurByte, OS);
|
|
else
|
|
EmitByte((EVEX_z << 7) |
|
|
(EVEX_L2 << 6) |
|
|
(VEX_L << 5) |
|
|
(EVEX_b << 4) |
|
|
(EVEX_V2 << 3) |
|
|
EVEX_aaa, CurByte, OS);
|
|
}
|
|
}
|
|
|
|
/// DetermineREXPrefix - Determine if the MCInst has to be encoded with a X86-64
|
|
/// REX prefix which specifies 1) 64-bit instructions, 2) non-default operand
|
|
/// size, and 3) use of X86-64 extended registers.
|
|
static unsigned DetermineREXPrefix(const MCInst &MI, uint64_t TSFlags,
|
|
const MCInstrDesc &Desc) {
|
|
unsigned REX = 0;
|
|
if (TSFlags & X86II::REX_W)
|
|
REX |= 1 << 3; // set REX.W
|
|
|
|
if (MI.getNumOperands() == 0) return REX;
|
|
|
|
unsigned NumOps = MI.getNumOperands();
|
|
// FIXME: MCInst should explicitize the two-addrness.
|
|
bool isTwoAddr = NumOps > 1 &&
|
|
Desc.getOperandConstraint(1, MCOI::TIED_TO) != -1;
|
|
|
|
// If it accesses SPL, BPL, SIL, or DIL, then it requires a 0x40 REX prefix.
|
|
unsigned i = isTwoAddr ? 1 : 0;
|
|
for (; i != NumOps; ++i) {
|
|
const MCOperand &MO = MI.getOperand(i);
|
|
if (!MO.isReg()) continue;
|
|
unsigned Reg = MO.getReg();
|
|
if (!X86II::isX86_64NonExtLowByteReg(Reg)) continue;
|
|
// FIXME: The caller of DetermineREXPrefix slaps this prefix onto anything
|
|
// that returns non-zero.
|
|
REX |= 0x40; // REX fixed encoding prefix
|
|
break;
|
|
}
|
|
|
|
switch (TSFlags & X86II::FormMask) {
|
|
case X86II::MRMSrcReg:
|
|
if (MI.getOperand(0).isReg() &&
|
|
X86II::isX86_64ExtendedReg(MI.getOperand(0).getReg()))
|
|
REX |= 1 << 2; // set REX.R
|
|
i = isTwoAddr ? 2 : 1;
|
|
for (; i != NumOps; ++i) {
|
|
const MCOperand &MO = MI.getOperand(i);
|
|
if (MO.isReg() && X86II::isX86_64ExtendedReg(MO.getReg()))
|
|
REX |= 1 << 0; // set REX.B
|
|
}
|
|
break;
|
|
case X86II::MRMSrcMem: {
|
|
if (MI.getOperand(0).isReg() &&
|
|
X86II::isX86_64ExtendedReg(MI.getOperand(0).getReg()))
|
|
REX |= 1 << 2; // set REX.R
|
|
unsigned Bit = 0;
|
|
i = isTwoAddr ? 2 : 1;
|
|
for (; i != NumOps; ++i) {
|
|
const MCOperand &MO = MI.getOperand(i);
|
|
if (MO.isReg()) {
|
|
if (X86II::isX86_64ExtendedReg(MO.getReg()))
|
|
REX |= 1 << Bit; // set REX.B (Bit=0) and REX.X (Bit=1)
|
|
Bit++;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
case X86II::MRMXm:
|
|
case X86II::MRM0m: case X86II::MRM1m:
|
|
case X86II::MRM2m: case X86II::MRM3m:
|
|
case X86II::MRM4m: case X86II::MRM5m:
|
|
case X86II::MRM6m: case X86II::MRM7m:
|
|
case X86II::MRMDestMem: {
|
|
unsigned e = (isTwoAddr ? X86::AddrNumOperands+1 : X86::AddrNumOperands);
|
|
i = isTwoAddr ? 1 : 0;
|
|
if (NumOps > e && MI.getOperand(e).isReg() &&
|
|
X86II::isX86_64ExtendedReg(MI.getOperand(e).getReg()))
|
|
REX |= 1 << 2; // set REX.R
|
|
unsigned Bit = 0;
|
|
for (; i != e; ++i) {
|
|
const MCOperand &MO = MI.getOperand(i);
|
|
if (MO.isReg()) {
|
|
if (X86II::isX86_64ExtendedReg(MO.getReg()))
|
|
REX |= 1 << Bit; // REX.B (Bit=0) and REX.X (Bit=1)
|
|
Bit++;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
default:
|
|
if (MI.getOperand(0).isReg() &&
|
|
X86II::isX86_64ExtendedReg(MI.getOperand(0).getReg()))
|
|
REX |= 1 << 0; // set REX.B
|
|
i = isTwoAddr ? 2 : 1;
|
|
for (unsigned e = NumOps; i != e; ++i) {
|
|
const MCOperand &MO = MI.getOperand(i);
|
|
if (MO.isReg() && X86II::isX86_64ExtendedReg(MO.getReg()))
|
|
REX |= 1 << 2; // set REX.R
|
|
}
|
|
break;
|
|
}
|
|
return REX;
|
|
}
|
|
|
|
/// EmitSegmentOverridePrefix - Emit segment override opcode prefix as needed
|
|
void X86MCCodeEmitter::EmitSegmentOverridePrefix(unsigned &CurByte,
|
|
unsigned SegOperand,
|
|
const MCInst &MI,
|
|
raw_ostream &OS) const {
|
|
// Check for explicit segment override on memory operand.
|
|
switch (MI.getOperand(SegOperand).getReg()) {
|
|
default: llvm_unreachable("Unknown segment register!");
|
|
case 0: break;
|
|
case X86::CS: EmitByte(0x2E, CurByte, OS); break;
|
|
case X86::SS: EmitByte(0x36, CurByte, OS); break;
|
|
case X86::DS: EmitByte(0x3E, CurByte, OS); break;
|
|
case X86::ES: EmitByte(0x26, CurByte, OS); break;
|
|
case X86::FS: EmitByte(0x64, CurByte, OS); break;
|
|
case X86::GS: EmitByte(0x65, CurByte, OS); break;
|
|
}
|
|
}
|
|
|
|
/// EmitOpcodePrefix - Emit all instruction prefixes prior to the opcode.
|
|
///
|
|
/// MemOperand is the operand # of the start of a memory operand if present. If
|
|
/// Not present, it is -1.
|
|
void X86MCCodeEmitter::EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte,
|
|
int MemOperand, const MCInst &MI,
|
|
const MCInstrDesc &Desc,
|
|
const MCSubtargetInfo &STI,
|
|
raw_ostream &OS) const {
|
|
|
|
// Emit the operand size opcode prefix as needed.
|
|
if ((TSFlags & X86II::OpSizeMask) == (is16BitMode(STI) ? X86II::OpSize32
|
|
: X86II::OpSize16))
|
|
EmitByte(0x66, CurByte, OS);
|
|
|
|
// Emit the LOCK opcode prefix.
|
|
if (TSFlags & X86II::LOCK)
|
|
EmitByte(0xF0, CurByte, OS);
|
|
|
|
switch (TSFlags & X86II::OpPrefixMask) {
|
|
case X86II::PD: // 66
|
|
EmitByte(0x66, CurByte, OS);
|
|
break;
|
|
case X86II::XS: // F3
|
|
EmitByte(0xF3, CurByte, OS);
|
|
break;
|
|
case X86II::XD: // F2
|
|
EmitByte(0xF2, CurByte, OS);
|
|
break;
|
|
}
|
|
|
|
// Handle REX prefix.
|
|
// FIXME: Can this come before F2 etc to simplify emission?
|
|
if (is64BitMode(STI)) {
|
|
if (unsigned REX = DetermineREXPrefix(MI, TSFlags, Desc))
|
|
EmitByte(0x40 | REX, CurByte, OS);
|
|
}
|
|
|
|
// 0x0F escape code must be emitted just before the opcode.
|
|
switch (TSFlags & X86II::OpMapMask) {
|
|
case X86II::TB: // Two-byte opcode map
|
|
case X86II::T8: // 0F 38
|
|
case X86II::TA: // 0F 3A
|
|
EmitByte(0x0F, CurByte, OS);
|
|
break;
|
|
}
|
|
|
|
switch (TSFlags & X86II::OpMapMask) {
|
|
case X86II::T8: // 0F 38
|
|
EmitByte(0x38, CurByte, OS);
|
|
break;
|
|
case X86II::TA: // 0F 3A
|
|
EmitByte(0x3A, CurByte, OS);
|
|
break;
|
|
}
|
|
}
|
|
|
|
void X86MCCodeEmitter::
|
|
encodeInstruction(const MCInst &MI, raw_ostream &OS,
|
|
SmallVectorImpl<MCFixup> &Fixups,
|
|
const MCSubtargetInfo &STI) const {
|
|
unsigned Opcode = MI.getOpcode();
|
|
const MCInstrDesc &Desc = MCII.get(Opcode);
|
|
uint64_t TSFlags = Desc.TSFlags;
|
|
|
|
// Pseudo instructions don't get encoded.
|
|
if ((TSFlags & X86II::FormMask) == X86II::Pseudo)
|
|
return;
|
|
|
|
unsigned NumOps = Desc.getNumOperands();
|
|
unsigned CurOp = X86II::getOperandBias(Desc);
|
|
|
|
// Keep track of the current byte being emitted.
|
|
unsigned CurByte = 0;
|
|
|
|
// Encoding type for this instruction.
|
|
uint64_t Encoding = TSFlags & X86II::EncodingMask;
|
|
|
|
// It uses the VEX.VVVV field?
|
|
bool HasVEX_4V = TSFlags & X86II::VEX_4V;
|
|
bool HasVEX_4VOp3 = TSFlags & X86II::VEX_4VOp3;
|
|
bool HasMemOp4 = TSFlags & X86II::MemOp4;
|
|
const unsigned MemOp4_I8IMMOperand = 2;
|
|
|
|
// It uses the EVEX.aaa field?
|
|
bool HasEVEX_K = TSFlags & X86II::EVEX_K;
|
|
bool HasEVEX_RC = TSFlags & X86II::EVEX_RC;
|
|
|
|
// Determine where the memory operand starts, if present.
|
|
int MemoryOperand = X86II::getMemoryOperandNo(TSFlags, Opcode);
|
|
if (MemoryOperand != -1) MemoryOperand += CurOp;
|
|
|
|
// Emit segment override opcode prefix as needed.
|
|
if (MemoryOperand >= 0)
|
|
EmitSegmentOverridePrefix(CurByte, MemoryOperand+X86::AddrSegmentReg,
|
|
MI, OS);
|
|
|
|
// Emit the repeat opcode prefix as needed.
|
|
if (TSFlags & X86II::REP)
|
|
EmitByte(0xF3, CurByte, OS);
|
|
|
|
// Emit the address size opcode prefix as needed.
|
|
bool need_address_override;
|
|
uint64_t AdSize = TSFlags & X86II::AdSizeMask;
|
|
if ((is16BitMode(STI) && AdSize == X86II::AdSize32) ||
|
|
(is32BitMode(STI) && AdSize == X86II::AdSize16) ||
|
|
(is64BitMode(STI) && AdSize == X86II::AdSize32)) {
|
|
need_address_override = true;
|
|
} else if (MemoryOperand < 0) {
|
|
need_address_override = false;
|
|
} else if (is64BitMode(STI)) {
|
|
assert(!Is16BitMemOperand(MI, MemoryOperand, STI));
|
|
need_address_override = Is32BitMemOperand(MI, MemoryOperand);
|
|
} else if (is32BitMode(STI)) {
|
|
assert(!Is64BitMemOperand(MI, MemoryOperand));
|
|
need_address_override = Is16BitMemOperand(MI, MemoryOperand, STI);
|
|
} else {
|
|
assert(is16BitMode(STI));
|
|
assert(!Is64BitMemOperand(MI, MemoryOperand));
|
|
need_address_override = !Is16BitMemOperand(MI, MemoryOperand, STI);
|
|
}
|
|
|
|
if (need_address_override)
|
|
EmitByte(0x67, CurByte, OS);
|
|
|
|
if (Encoding == 0)
|
|
EmitOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, STI, OS);
|
|
else
|
|
EmitVEXOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, OS);
|
|
|
|
unsigned char BaseOpcode = X86II::getBaseOpcodeFor(TSFlags);
|
|
|
|
if (TSFlags & X86II::Has3DNow0F0FOpcode)
|
|
BaseOpcode = 0x0F; // Weird 3DNow! encoding.
|
|
|
|
unsigned SrcRegNum = 0;
|
|
switch (TSFlags & X86II::FormMask) {
|
|
default: errs() << "FORM: " << (TSFlags & X86II::FormMask) << "\n";
|
|
llvm_unreachable("Unknown FormMask value in X86MCCodeEmitter!");
|
|
case X86II::Pseudo:
|
|
llvm_unreachable("Pseudo instruction shouldn't be emitted");
|
|
case X86II::RawFrmDstSrc: {
|
|
unsigned siReg = MI.getOperand(1).getReg();
|
|
assert(((siReg == X86::SI && MI.getOperand(0).getReg() == X86::DI) ||
|
|
(siReg == X86::ESI && MI.getOperand(0).getReg() == X86::EDI) ||
|
|
(siReg == X86::RSI && MI.getOperand(0).getReg() == X86::RDI)) &&
|
|
"SI and DI register sizes do not match");
|
|
// Emit segment override opcode prefix as needed (not for %ds).
|
|
if (MI.getOperand(2).getReg() != X86::DS)
|
|
EmitSegmentOverridePrefix(CurByte, 2, MI, OS);
|
|
// Emit AdSize prefix as needed.
|
|
if ((!is32BitMode(STI) && siReg == X86::ESI) ||
|
|
(is32BitMode(STI) && siReg == X86::SI))
|
|
EmitByte(0x67, CurByte, OS);
|
|
CurOp += 3; // Consume operands.
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
break;
|
|
}
|
|
case X86II::RawFrmSrc: {
|
|
unsigned siReg = MI.getOperand(0).getReg();
|
|
// Emit segment override opcode prefix as needed (not for %ds).
|
|
if (MI.getOperand(1).getReg() != X86::DS)
|
|
EmitSegmentOverridePrefix(CurByte, 1, MI, OS);
|
|
// Emit AdSize prefix as needed.
|
|
if ((!is32BitMode(STI) && siReg == X86::ESI) ||
|
|
(is32BitMode(STI) && siReg == X86::SI))
|
|
EmitByte(0x67, CurByte, OS);
|
|
CurOp += 2; // Consume operands.
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
break;
|
|
}
|
|
case X86II::RawFrmDst: {
|
|
unsigned siReg = MI.getOperand(0).getReg();
|
|
// Emit AdSize prefix as needed.
|
|
if ((!is32BitMode(STI) && siReg == X86::EDI) ||
|
|
(is32BitMode(STI) && siReg == X86::DI))
|
|
EmitByte(0x67, CurByte, OS);
|
|
++CurOp; // Consume operand.
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
break;
|
|
}
|
|
case X86II::RawFrm:
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
break;
|
|
case X86II::RawFrmMemOffs:
|
|
// Emit segment override opcode prefix as needed.
|
|
EmitSegmentOverridePrefix(CurByte, 1, MI, OS);
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
EmitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
|
|
X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
|
|
CurByte, OS, Fixups);
|
|
++CurOp; // skip segment operand
|
|
break;
|
|
case X86II::RawFrmImm8:
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
EmitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
|
|
X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
|
|
CurByte, OS, Fixups);
|
|
EmitImmediate(MI.getOperand(CurOp++), MI.getLoc(), 1, FK_Data_1, CurByte,
|
|
OS, Fixups);
|
|
break;
|
|
case X86II::RawFrmImm16:
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
EmitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
|
|
X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
|
|
CurByte, OS, Fixups);
|
|
EmitImmediate(MI.getOperand(CurOp++), MI.getLoc(), 2, FK_Data_2, CurByte,
|
|
OS, Fixups);
|
|
break;
|
|
|
|
case X86II::AddRegFrm:
|
|
EmitByte(BaseOpcode + GetX86RegNum(MI.getOperand(CurOp++)), CurByte, OS);
|
|
break;
|
|
|
|
case X86II::MRMDestReg:
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
SrcRegNum = CurOp + 1;
|
|
|
|
if (HasEVEX_K) // Skip writemask
|
|
SrcRegNum++;
|
|
|
|
if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV)
|
|
++SrcRegNum;
|
|
|
|
EmitRegModRMByte(MI.getOperand(CurOp),
|
|
GetX86RegNum(MI.getOperand(SrcRegNum)), CurByte, OS);
|
|
CurOp = SrcRegNum + 1;
|
|
break;
|
|
|
|
case X86II::MRMDestMem:
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
SrcRegNum = CurOp + X86::AddrNumOperands;
|
|
|
|
if (HasEVEX_K) // Skip writemask
|
|
SrcRegNum++;
|
|
|
|
if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV)
|
|
++SrcRegNum;
|
|
|
|
EmitMemModRMByte(MI, CurOp,
|
|
GetX86RegNum(MI.getOperand(SrcRegNum)),
|
|
TSFlags, CurByte, OS, Fixups, STI);
|
|
CurOp = SrcRegNum + 1;
|
|
break;
|
|
|
|
case X86II::MRMSrcReg:
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
SrcRegNum = CurOp + 1;
|
|
|
|
if (HasEVEX_K) // Skip writemask
|
|
SrcRegNum++;
|
|
|
|
if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV)
|
|
++SrcRegNum;
|
|
|
|
if (HasMemOp4) // Skip 2nd src (which is encoded in I8IMM)
|
|
++SrcRegNum;
|
|
|
|
EmitRegModRMByte(MI.getOperand(SrcRegNum),
|
|
GetX86RegNum(MI.getOperand(CurOp)), CurByte, OS);
|
|
|
|
// 2 operands skipped with HasMemOp4, compensate accordingly
|
|
CurOp = HasMemOp4 ? SrcRegNum : SrcRegNum + 1;
|
|
if (HasVEX_4VOp3)
|
|
++CurOp;
|
|
// do not count the rounding control operand
|
|
if (HasEVEX_RC)
|
|
NumOps--;
|
|
break;
|
|
|
|
case X86II::MRMSrcMem: {
|
|
int AddrOperands = X86::AddrNumOperands;
|
|
unsigned FirstMemOp = CurOp+1;
|
|
|
|
if (HasEVEX_K) { // Skip writemask
|
|
++AddrOperands;
|
|
++FirstMemOp;
|
|
}
|
|
|
|
if (HasVEX_4V) {
|
|
++AddrOperands;
|
|
++FirstMemOp; // Skip the register source (which is encoded in VEX_VVVV).
|
|
}
|
|
if (HasMemOp4) // Skip second register source (encoded in I8IMM)
|
|
++FirstMemOp;
|
|
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
|
|
EmitMemModRMByte(MI, FirstMemOp, GetX86RegNum(MI.getOperand(CurOp)),
|
|
TSFlags, CurByte, OS, Fixups, STI);
|
|
CurOp += AddrOperands + 1;
|
|
if (HasVEX_4VOp3)
|
|
++CurOp;
|
|
break;
|
|
}
|
|
|
|
case X86II::MRMXr:
|
|
case X86II::MRM0r: case X86II::MRM1r:
|
|
case X86II::MRM2r: case X86II::MRM3r:
|
|
case X86II::MRM4r: case X86II::MRM5r:
|
|
case X86II::MRM6r: case X86II::MRM7r: {
|
|
if (HasVEX_4V) // Skip the register dst (which is encoded in VEX_VVVV).
|
|
++CurOp;
|
|
if (HasEVEX_K) // Skip writemask
|
|
++CurOp;
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
uint64_t Form = TSFlags & X86II::FormMask;
|
|
EmitRegModRMByte(MI.getOperand(CurOp++),
|
|
(Form == X86II::MRMXr) ? 0 : Form-X86II::MRM0r,
|
|
CurByte, OS);
|
|
break;
|
|
}
|
|
|
|
case X86II::MRMXm:
|
|
case X86II::MRM0m: case X86II::MRM1m:
|
|
case X86II::MRM2m: case X86II::MRM3m:
|
|
case X86II::MRM4m: case X86II::MRM5m:
|
|
case X86II::MRM6m: case X86II::MRM7m: {
|
|
if (HasVEX_4V) // Skip the register dst (which is encoded in VEX_VVVV).
|
|
++CurOp;
|
|
if (HasEVEX_K) // Skip writemask
|
|
++CurOp;
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
uint64_t Form = TSFlags & X86II::FormMask;
|
|
EmitMemModRMByte(MI, CurOp, (Form == X86II::MRMXm) ? 0 : Form-X86II::MRM0m,
|
|
TSFlags, CurByte, OS, Fixups, STI);
|
|
CurOp += X86::AddrNumOperands;
|
|
break;
|
|
}
|
|
case X86II::MRM_C0: case X86II::MRM_C1: case X86II::MRM_C2:
|
|
case X86II::MRM_C3: case X86II::MRM_C4: case X86II::MRM_C5:
|
|
case X86II::MRM_C6: case X86II::MRM_C7: case X86II::MRM_C8:
|
|
case X86II::MRM_C9: case X86II::MRM_CA: case X86II::MRM_CB:
|
|
case X86II::MRM_CC: case X86II::MRM_CD: case X86II::MRM_CE:
|
|
case X86II::MRM_CF: case X86II::MRM_D0: case X86II::MRM_D1:
|
|
case X86II::MRM_D2: case X86II::MRM_D3: case X86II::MRM_D4:
|
|
case X86II::MRM_D5: case X86II::MRM_D6: case X86II::MRM_D7:
|
|
case X86II::MRM_D8: case X86II::MRM_D9: case X86II::MRM_DA:
|
|
case X86II::MRM_DB: case X86II::MRM_DC: case X86II::MRM_DD:
|
|
case X86II::MRM_DE: case X86II::MRM_DF: case X86II::MRM_E0:
|
|
case X86II::MRM_E1: case X86II::MRM_E2: case X86II::MRM_E3:
|
|
case X86II::MRM_E4: case X86II::MRM_E5: case X86II::MRM_E6:
|
|
case X86II::MRM_E7: case X86II::MRM_E8: case X86II::MRM_E9:
|
|
case X86II::MRM_EA: case X86II::MRM_EB: case X86II::MRM_EC:
|
|
case X86II::MRM_ED: case X86II::MRM_EE: case X86II::MRM_EF:
|
|
case X86II::MRM_F0: case X86II::MRM_F1: case X86II::MRM_F2:
|
|
case X86II::MRM_F3: case X86II::MRM_F4: case X86II::MRM_F5:
|
|
case X86II::MRM_F6: case X86II::MRM_F7: case X86II::MRM_F8:
|
|
case X86II::MRM_F9: case X86II::MRM_FA: case X86II::MRM_FB:
|
|
case X86II::MRM_FC: case X86II::MRM_FD: case X86II::MRM_FE:
|
|
case X86II::MRM_FF:
|
|
EmitByte(BaseOpcode, CurByte, OS);
|
|
|
|
uint64_t Form = TSFlags & X86II::FormMask;
|
|
EmitByte(0xC0 + Form - X86II::MRM_C0, CurByte, OS);
|
|
break;
|
|
}
|
|
|
|
// If there is a remaining operand, it must be a trailing immediate. Emit it
|
|
// according to the right size for the instruction. Some instructions
|
|
// (SSE4a extrq and insertq) have two trailing immediates.
|
|
while (CurOp != NumOps && NumOps - CurOp <= 2) {
|
|
// The last source register of a 4 operand instruction in AVX is encoded
|
|
// in bits[7:4] of a immediate byte.
|
|
if (TSFlags & X86II::VEX_I8IMM) {
|
|
const MCOperand &MO = MI.getOperand(HasMemOp4 ? MemOp4_I8IMMOperand
|
|
: CurOp);
|
|
++CurOp;
|
|
unsigned RegNum = GetX86RegNum(MO) << 4;
|
|
if (X86II::isX86_64ExtendedReg(MO.getReg()))
|
|
RegNum |= 1 << 7;
|
|
// If there is an additional 5th operand it must be an immediate, which
|
|
// is encoded in bits[3:0]
|
|
if (CurOp != NumOps) {
|
|
const MCOperand &MIMM = MI.getOperand(CurOp++);
|
|
if (MIMM.isImm()) {
|
|
unsigned Val = MIMM.getImm();
|
|
assert(Val < 16 && "Immediate operand value out of range");
|
|
RegNum |= Val;
|
|
}
|
|
}
|
|
EmitImmediate(MCOperand::createImm(RegNum), MI.getLoc(), 1, FK_Data_1,
|
|
CurByte, OS, Fixups);
|
|
} else {
|
|
EmitImmediate(MI.getOperand(CurOp++), MI.getLoc(),
|
|
X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags),
|
|
CurByte, OS, Fixups);
|
|
}
|
|
}
|
|
|
|
if (TSFlags & X86II::Has3DNow0F0FOpcode)
|
|
EmitByte(X86II::getBaseOpcodeFor(TSFlags), CurByte, OS);
|
|
|
|
#ifndef NDEBUG
|
|
// FIXME: Verify.
|
|
if (/*!Desc.isVariadic() &&*/ CurOp != NumOps) {
|
|
errs() << "Cannot encode all operands of: ";
|
|
MI.dump();
|
|
errs() << '\n';
|
|
abort();
|
|
}
|
|
#endif
|
|
}
|