| //===-- X86MCCodeEmitter.cpp - Convert X86 code to machine code -----------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the X86MCCodeEmitter class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "MCTargetDesc/X86MCTargetDesc.h" |
| #include "MCTargetDesc/X86BaseInfo.h" |
| #include "MCTargetDesc/X86FixupKinds.h" |
| #include "llvm/MC/MCCodeEmitter.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCInst.h" |
| #include "llvm/MC/MCInstrInfo.h" |
| #include "llvm/MC/MCRegisterInfo.h" |
| #include "llvm/MC/MCSubtargetInfo.h" |
| #include "llvm/MC/MCSymbol.h" |
| #include "llvm/Support/raw_ostream.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "mccodeemitter" |
| |
| namespace { |
| class X86MCCodeEmitter : public MCCodeEmitter { |
| X86MCCodeEmitter(const X86MCCodeEmitter &) = delete; |
| void operator=(const X86MCCodeEmitter &) = delete; |
| const MCInstrInfo &MCII; |
| MCContext &Ctx; |
| public: |
| X86MCCodeEmitter(const MCInstrInfo &mcii, MCContext &ctx) |
| : MCII(mcii), Ctx(ctx) { |
| } |
| |
| ~X86MCCodeEmitter() override {} |
| |
| bool is64BitMode(const MCSubtargetInfo &STI) const { |
| return STI.getFeatureBits()[X86::Mode64Bit]; |
| } |
| |
| bool is32BitMode(const MCSubtargetInfo &STI) const { |
| return STI.getFeatureBits()[X86::Mode32Bit]; |
| } |
| |
| bool is16BitMode(const MCSubtargetInfo &STI) const { |
| return STI.getFeatureBits()[X86::Mode16Bit]; |
| } |
| |
| /// Is16BitMemOperand - Return true if the specified instruction has |
| /// a 16-bit memory operand. Op specifies the operand # of the memoperand. |
| bool Is16BitMemOperand(const MCInst &MI, unsigned Op, |
| const MCSubtargetInfo &STI) const { |
| const MCOperand &BaseReg = MI.getOperand(Op+X86::AddrBaseReg); |
| const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg); |
| const MCOperand &Disp = MI.getOperand(Op+X86::AddrDisp); |
| |
| if (is16BitMode(STI) && BaseReg.getReg() == 0 && |
| Disp.isImm() && Disp.getImm() < 0x10000) |
| return true; |
| if ((BaseReg.getReg() != 0 && |
| X86MCRegisterClasses[X86::GR16RegClassID].contains(BaseReg.getReg())) || |
| (IndexReg.getReg() != 0 && |
| X86MCRegisterClasses[X86::GR16RegClassID].contains(IndexReg.getReg()))) |
| return true; |
| return false; |
| } |
| |
| unsigned GetX86RegNum(const MCOperand &MO) const { |
| return Ctx.getRegisterInfo()->getEncodingValue(MO.getReg()) & 0x7; |
| } |
| |
| unsigned getX86RegEncoding(const MCInst &MI, unsigned OpNum) const { |
| return Ctx.getRegisterInfo()->getEncodingValue( |
| MI.getOperand(OpNum).getReg()); |
| } |
| |
| bool isX86_64ExtendedReg(const MCInst &MI, unsigned OpNum) const { |
| return (getX86RegEncoding(MI, OpNum) >> 3) & 1; |
| } |
| |
| void EmitByte(uint8_t C, unsigned &CurByte, raw_ostream &OS) const { |
| OS << (char)C; |
| ++CurByte; |
| } |
| |
| void EmitConstant(uint64_t Val, unsigned Size, unsigned &CurByte, |
| raw_ostream &OS) const { |
| // Output the constant in little endian byte order. |
| for (unsigned i = 0; i != Size; ++i) { |
| EmitByte(Val & 255, CurByte, OS); |
| Val >>= 8; |
| } |
| } |
| |
| void EmitImmediate(const MCOperand &Disp, SMLoc Loc, |
| unsigned ImmSize, MCFixupKind FixupKind, |
| unsigned &CurByte, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups, |
| int ImmOffset = 0) const; |
| |
| inline static uint8_t ModRMByte(unsigned Mod, unsigned RegOpcode, |
| unsigned RM) { |
| assert(Mod < 4 && RegOpcode < 8 && RM < 8 && "ModRM Fields out of range!"); |
| return RM | (RegOpcode << 3) | (Mod << 6); |
| } |
| |
| void EmitRegModRMByte(const MCOperand &ModRMReg, unsigned RegOpcodeFld, |
| unsigned &CurByte, raw_ostream &OS) const { |
| EmitByte(ModRMByte(3, RegOpcodeFld, GetX86RegNum(ModRMReg)), CurByte, OS); |
| } |
| |
| void EmitSIBByte(unsigned SS, unsigned Index, unsigned Base, |
| unsigned &CurByte, raw_ostream &OS) const { |
| // SIB byte is in the same format as the ModRMByte. |
| EmitByte(ModRMByte(SS, Index, Base), CurByte, OS); |
| } |
| |
| |
| void EmitMemModRMByte(const MCInst &MI, unsigned Op, |
| unsigned RegOpcodeField, |
| uint64_t TSFlags, unsigned &CurByte, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups, |
| const MCSubtargetInfo &STI) const; |
| |
| void encodeInstruction(const MCInst &MI, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups, |
| const MCSubtargetInfo &STI) const override; |
| |
| void EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand, |
| const MCInst &MI, const MCInstrDesc &Desc, |
| raw_ostream &OS) const; |
| |
| void EmitSegmentOverridePrefix(unsigned &CurByte, unsigned SegOperand, |
| const MCInst &MI, raw_ostream &OS) const; |
| |
| void EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand, |
| const MCInst &MI, const MCInstrDesc &Desc, |
| const MCSubtargetInfo &STI, |
| raw_ostream &OS) const; |
| |
| uint8_t DetermineREXPrefix(const MCInst &MI, uint64_t TSFlags, |
| int MemOperand, const MCInstrDesc &Desc) const; |
| }; |
| |
| } // end anonymous namespace |
| |
| MCCodeEmitter *llvm::createX86MCCodeEmitter(const MCInstrInfo &MCII, |
| const MCRegisterInfo &MRI, |
| MCContext &Ctx) { |
| return new X86MCCodeEmitter(MCII, Ctx); |
| } |
| |
| /// isDisp8 - Return true if this signed displacement fits in a 8-bit |
| /// sign-extended field. |
| static bool isDisp8(int Value) { |
| return Value == (int8_t)Value; |
| } |
| |
| /// isCDisp8 - Return true if this signed displacement fits in a 8-bit |
| /// compressed dispacement field. |
| static bool isCDisp8(uint64_t TSFlags, int Value, int& CValue) { |
| assert(((TSFlags & X86II::EncodingMask) == X86II::EVEX) && |
| "Compressed 8-bit displacement is only valid for EVEX inst."); |
| |
| unsigned CD8_Scale = |
| (TSFlags & X86II::CD8_Scale_Mask) >> X86II::CD8_Scale_Shift; |
| if (CD8_Scale == 0) { |
| CValue = Value; |
| return isDisp8(Value); |
| } |
| |
| unsigned Mask = CD8_Scale - 1; |
| assert((CD8_Scale & Mask) == 0 && "Invalid memory object size."); |
| if (Value & Mask) // Unaligned offset |
| return false; |
| Value /= (int)CD8_Scale; |
| bool Ret = (Value == (int8_t)Value); |
| |
| if (Ret) |
| CValue = Value; |
| return Ret; |
| } |
| |
| /// getImmFixupKind - Return the appropriate fixup kind to use for an immediate |
| /// in an instruction with the specified TSFlags. |
| static MCFixupKind getImmFixupKind(uint64_t TSFlags) { |
| unsigned Size = X86II::getSizeOfImm(TSFlags); |
| bool isPCRel = X86II::isImmPCRel(TSFlags); |
| |
| if (X86II::isImmSigned(TSFlags)) { |
| switch (Size) { |
| default: llvm_unreachable("Unsupported signed fixup size!"); |
| case 4: return MCFixupKind(X86::reloc_signed_4byte); |
| } |
| } |
| return MCFixup::getKindForSize(Size, isPCRel); |
| } |
| |
| /// Is32BitMemOperand - Return true if the specified instruction has |
| /// a 32-bit memory operand. Op specifies the operand # of the memoperand. |
| static bool Is32BitMemOperand(const MCInst &MI, unsigned Op) { |
| const MCOperand &BaseReg = MI.getOperand(Op+X86::AddrBaseReg); |
| const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg); |
| |
| if ((BaseReg.getReg() != 0 && |
| X86MCRegisterClasses[X86::GR32RegClassID].contains(BaseReg.getReg())) || |
| (IndexReg.getReg() != 0 && |
| X86MCRegisterClasses[X86::GR32RegClassID].contains(IndexReg.getReg()))) |
| return true; |
| if (BaseReg.getReg() == X86::EIP) { |
| assert(IndexReg.getReg() == 0 && "Invalid eip-based address."); |
| return true; |
| } |
| return false; |
| } |
| |
| /// Is64BitMemOperand - Return true if the specified instruction has |
| /// a 64-bit memory operand. Op specifies the operand # of the memoperand. |
| #ifndef NDEBUG |
| static bool Is64BitMemOperand(const MCInst &MI, unsigned Op) { |
| const MCOperand &BaseReg = MI.getOperand(Op+X86::AddrBaseReg); |
| const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg); |
| |
| if ((BaseReg.getReg() != 0 && |
| X86MCRegisterClasses[X86::GR64RegClassID].contains(BaseReg.getReg())) || |
| (IndexReg.getReg() != 0 && |
| X86MCRegisterClasses[X86::GR64RegClassID].contains(IndexReg.getReg()))) |
| return true; |
| return false; |
| } |
| #endif |
| |
| /// StartsWithGlobalOffsetTable - Check if this expression starts with |
| /// _GLOBAL_OFFSET_TABLE_ and if it is of the form |
| /// _GLOBAL_OFFSET_TABLE_-symbol. This is needed to support PIC on ELF |
| /// i386 as _GLOBAL_OFFSET_TABLE_ is magical. We check only simple case that |
| /// are know to be used: _GLOBAL_OFFSET_TABLE_ by itself or at the start |
| /// of a binary expression. |
| enum GlobalOffsetTableExprKind { |
| GOT_None, |
| GOT_Normal, |
| GOT_SymDiff |
| }; |
| static GlobalOffsetTableExprKind |
| StartsWithGlobalOffsetTable(const MCExpr *Expr) { |
| const MCExpr *RHS = nullptr; |
| if (Expr->getKind() == MCExpr::Binary) { |
| const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(Expr); |
| Expr = BE->getLHS(); |
| RHS = BE->getRHS(); |
| } |
| |
| if (Expr->getKind() != MCExpr::SymbolRef) |
| return GOT_None; |
| |
| const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Expr); |
| const MCSymbol &S = Ref->getSymbol(); |
| if (S.getName() != "_GLOBAL_OFFSET_TABLE_") |
| return GOT_None; |
| if (RHS && RHS->getKind() == MCExpr::SymbolRef) |
| return GOT_SymDiff; |
| return GOT_Normal; |
| } |
| |
| static bool HasSecRelSymbolRef(const MCExpr *Expr) { |
| if (Expr->getKind() == MCExpr::SymbolRef) { |
| const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Expr); |
| return Ref->getKind() == MCSymbolRefExpr::VK_SECREL; |
| } |
| return false; |
| } |
| |
| void X86MCCodeEmitter:: |
| EmitImmediate(const MCOperand &DispOp, SMLoc Loc, unsigned Size, |
| MCFixupKind FixupKind, unsigned &CurByte, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups, int ImmOffset) const { |
| const MCExpr *Expr = nullptr; |
| if (DispOp.isImm()) { |
| // If this is a simple integer displacement that doesn't require a |
| // relocation, emit it now. |
| if (FixupKind != FK_PCRel_1 && |
| FixupKind != FK_PCRel_2 && |
| FixupKind != FK_PCRel_4) { |
| EmitConstant(DispOp.getImm()+ImmOffset, Size, CurByte, OS); |
| return; |
| } |
| Expr = MCConstantExpr::create(DispOp.getImm(), Ctx); |
| } else { |
| Expr = DispOp.getExpr(); |
| } |
| |
| // If we have an immoffset, add it to the expression. |
| if ((FixupKind == FK_Data_4 || |
| FixupKind == FK_Data_8 || |
| FixupKind == MCFixupKind(X86::reloc_signed_4byte))) { |
| GlobalOffsetTableExprKind Kind = StartsWithGlobalOffsetTable(Expr); |
| if (Kind != GOT_None) { |
| assert(ImmOffset == 0); |
| |
| if (Size == 8) { |
| FixupKind = MCFixupKind(X86::reloc_global_offset_table8); |
| } else { |
| assert(Size == 4); |
| FixupKind = MCFixupKind(X86::reloc_global_offset_table); |
| } |
| |
| if (Kind == GOT_Normal) |
| ImmOffset = CurByte; |
| } else if (Expr->getKind() == MCExpr::SymbolRef) { |
| if (HasSecRelSymbolRef(Expr)) { |
| FixupKind = MCFixupKind(FK_SecRel_4); |
| } |
| } else if (Expr->getKind() == MCExpr::Binary) { |
| const MCBinaryExpr *Bin = static_cast<const MCBinaryExpr*>(Expr); |
| if (HasSecRelSymbolRef(Bin->getLHS()) |
| || HasSecRelSymbolRef(Bin->getRHS())) { |
| FixupKind = MCFixupKind(FK_SecRel_4); |
| } |
| } |
| } |
| |
| // If the fixup is pc-relative, we need to bias the value to be relative to |
| // the start of the field, not the end of the field. |
| if (FixupKind == FK_PCRel_4 || |
| FixupKind == MCFixupKind(X86::reloc_riprel_4byte) || |
| FixupKind == MCFixupKind(X86::reloc_riprel_4byte_movq_load)) |
| ImmOffset -= 4; |
| if (FixupKind == FK_PCRel_2) |
| ImmOffset -= 2; |
| if (FixupKind == FK_PCRel_1) |
| ImmOffset -= 1; |
| |
| if (ImmOffset) |
| Expr = MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(ImmOffset, Ctx), |
| Ctx); |
| |
| // Emit a symbolic constant as a fixup and 4 zeros. |
| Fixups.push_back(MCFixup::create(CurByte, Expr, FixupKind, Loc)); |
| EmitConstant(0, Size, CurByte, OS); |
| } |
| |
| void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op, |
| unsigned RegOpcodeField, |
| uint64_t TSFlags, unsigned &CurByte, |
| raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups, |
| const MCSubtargetInfo &STI) const{ |
| const MCOperand &Disp = MI.getOperand(Op+X86::AddrDisp); |
| const MCOperand &Base = MI.getOperand(Op+X86::AddrBaseReg); |
| const MCOperand &Scale = MI.getOperand(Op+X86::AddrScaleAmt); |
| const MCOperand &IndexReg = MI.getOperand(Op+X86::AddrIndexReg); |
| unsigned BaseReg = Base.getReg(); |
| bool HasEVEX = (TSFlags & X86II::EncodingMask) == X86II::EVEX; |
| |
| // Handle %rip relative addressing. |
| if (BaseReg == X86::RIP || |
| BaseReg == X86::EIP) { // [disp32+rIP] in X86-64 mode |
| assert(is64BitMode(STI) && "Rip-relative addressing requires 64-bit mode"); |
| assert(IndexReg.getReg() == 0 && "Invalid rip-relative address"); |
| EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS); |
| |
| unsigned FixupKind = X86::reloc_riprel_4byte; |
| |
| // movq loads are handled with a special relocation form which allows the |
| // linker to eliminate some loads for GOT references which end up in the |
| // same linkage unit. |
| if (MI.getOpcode() == X86::MOV64rm) |
| FixupKind = X86::reloc_riprel_4byte_movq_load; |
| |
| // rip-relative addressing is actually relative to the *next* instruction. |
| // Since an immediate can follow the mod/rm byte for an instruction, this |
| // means that we need to bias the immediate field of the instruction with |
| // the size of the immediate field. If we have this case, add it into the |
| // expression to emit. |
| int ImmSize = X86II::hasImm(TSFlags) ? X86II::getSizeOfImm(TSFlags) : 0; |
| |
| EmitImmediate(Disp, MI.getLoc(), 4, MCFixupKind(FixupKind), |
| CurByte, OS, Fixups, -ImmSize); |
| return; |
| } |
| |
| unsigned BaseRegNo = BaseReg ? GetX86RegNum(Base) : -1U; |
| |
| // 16-bit addressing forms of the ModR/M byte have a different encoding for |
| // the R/M field and are far more limited in which registers can be used. |
| if (Is16BitMemOperand(MI, Op, STI)) { |
| if (BaseReg) { |
| // For 32-bit addressing, the row and column values in Table 2-2 are |
| // basically the same. It's AX/CX/DX/BX/SP/BP/SI/DI in that order, with |
| // some special cases. And GetX86RegNum reflects that numbering. |
| // For 16-bit addressing it's more fun, as shown in the SDM Vol 2A, |
| // Table 2-1 "16-Bit Addressing Forms with the ModR/M byte". We can only |
| // use SI/DI/BP/BX, which have "row" values 4-7 in no particular order, |
| // while values 0-3 indicate the allowed combinations (base+index) of |
| // those: 0 for BX+SI, 1 for BX+DI, 2 for BP+SI, 3 for BP+DI. |
| // |
| // R16Table[] is a lookup from the normal RegNo, to the row values from |
| // Table 2-1 for 16-bit addressing modes. Where zero means disallowed. |
| static const unsigned R16Table[] = { 0, 0, 0, 7, 0, 6, 4, 5 }; |
| unsigned RMfield = R16Table[BaseRegNo]; |
| |
| assert(RMfield && "invalid 16-bit base register"); |
| |
| if (IndexReg.getReg()) { |
| unsigned IndexReg16 = R16Table[GetX86RegNum(IndexReg)]; |
| |
| assert(IndexReg16 && "invalid 16-bit index register"); |
| // We must have one of SI/DI (4,5), and one of BP/BX (6,7). |
| assert(((IndexReg16 ^ RMfield) & 2) && |
| "invalid 16-bit base/index register combination"); |
| assert(Scale.getImm() == 1 && |
| "invalid scale for 16-bit memory reference"); |
| |
| // Allow base/index to appear in either order (although GAS doesn't). |
| if (IndexReg16 & 2) |
| RMfield = (RMfield & 1) | ((7 - IndexReg16) << 1); |
| else |
| RMfield = (IndexReg16 & 1) | ((7 - RMfield) << 1); |
| } |
| |
| if (Disp.isImm() && isDisp8(Disp.getImm())) { |
| if (Disp.getImm() == 0 && BaseRegNo != N86::EBP) { |
| // 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) |
| // |
| uint8_t VEX_R = 0x1; |
| uint8_t 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) |
| uint8_t 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) |
| // |
| uint8_t VEX_B = 0x1; |
| |
| // VEX_W: opcode specific (use like REX.W, or used for |
| // opcode extension, or ignored, depending on the opcode byte) |
| uint8_t VEX_W = (TSFlags & X86II::VEX_W) ? 1 : 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 |
| uint8_t VEX_5M; |
| 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; |
| } |
| |
| // VEX_4V (VEX vvvv field): a register specifier |
| // (in 1's complement form) or 1111 if unused. |
| uint8_t VEX_4V = 0xf; |
| uint8_t EVEX_V2 = 0x1; |
| |
| // EVEX_L2/VEX_L (Vector Length): |
| // |
| // L2 L |
| // 0 0: scalar or 128-bit vector |
| // 0 1: 256-bit vector |
| // 1 0: 512-bit vector |
| // |
| uint8_t VEX_L = (TSFlags & X86II::VEX_L) ? 1 : 0; |
| uint8_t EVEX_L2 = (TSFlags & X86II::EVEX_L2) ? 1 : 0; |
| |
| // VEX_PP: opcode extension providing equivalent |
| // functionality of a SIMD prefix |
| // |
| // 0b00: None |
| // 0b01: 66 |
| // 0b10: F3 |
| // 0b11: F2 |
| // |
| uint8_t VEX_PP; |
| switch (TSFlags & X86II::OpPrefixMask) { |
| default: llvm_unreachable("Invalid op prefix!"); |
| case X86II::PS: VEX_PP = 0x0; break; // none |
| case X86II::PD: VEX_PP = 0x1; break; // 66 |
| case X86II::XS: VEX_PP = 0x2; break; // F3 |
| case X86II::XD: VEX_PP = 0x3; break; // F2 |
| } |
| |
| // EVEX_U |
| uint8_t EVEX_U = 1; // Always '1' so far |
| |
| // EVEX_z |
| uint8_t EVEX_z = (HasEVEX_K && (TSFlags & X86II::EVEX_Z)) ? 1 : 0; |
| |
| // EVEX_b |
| uint8_t EVEX_b = (TSFlags & X86II::EVEX_B) ? 1 : 0; |
| |
| // EVEX_rc |
| uint8_t EVEX_rc = 0; |
| |
| // EVEX_aaa |
| uint8_t EVEX_aaa = 0; |
| |
| bool EncodeRC = false; |
| |
| // 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 |
| // |
| unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg); |
| VEX_B = ~(BaseRegEnc >> 3) & 1; |
| unsigned IndexRegEnc = getX86RegEncoding(MI, MemOperand+X86::AddrIndexReg); |
| VEX_X = ~(IndexRegEnc >> 3) & 1; |
| if (!HasVEX_4V) // Only needed with VSIB which don't use VVVV. |
| EVEX_V2 = ~(IndexRegEnc >> 4) & 1; |
| |
| CurOp += X86::AddrNumOperands; |
| |
| if (HasEVEX_K) |
| EVEX_aaa = getX86RegEncoding(MI, CurOp++); |
| |
| if (HasVEX_4V) { |
| unsigned VRegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_4V = ~VRegEnc & 0xf; |
| EVEX_V2 = ~(VRegEnc >> 4) & 1; |
| } |
| |
| unsigned RegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_R = ~(RegEnc >> 3) & 1; |
| EVEX_R2 = ~(RegEnc >> 4) & 1; |
| 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), |
| unsigned RegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_R = ~(RegEnc >> 3) & 1; |
| EVEX_R2 = ~(RegEnc >> 4) & 1; |
| |
| if (HasEVEX_K) |
| EVEX_aaa = getX86RegEncoding(MI, CurOp++); |
| |
| if (HasVEX_4V) { |
| unsigned VRegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_4V = ~VRegEnc & 0xf; |
| EVEX_V2 = ~(VRegEnc >> 4) & 1; |
| } |
| |
| unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg); |
| VEX_B = ~(BaseRegEnc >> 3) & 1; |
| unsigned IndexRegEnc = getX86RegEncoding(MI, MemOperand+X86::AddrIndexReg); |
| VEX_X = ~(IndexRegEnc >> 3) & 1; |
| if (!HasVEX_4V) // Only needed with VSIB which don't use VVVV. |
| EVEX_V2 = ~(IndexRegEnc >> 4) & 1; |
| |
| 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 = ~getX86RegEncoding(MI, CurOp + X86::AddrNumOperands) & 0xf; |
| 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) { |
| unsigned VRegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_4V = ~VRegEnc & 0xf; |
| EVEX_V2 = ~(VRegEnc >> 4) & 1; |
| } |
| |
| if (HasEVEX_K) |
| EVEX_aaa = getX86RegEncoding(MI, CurOp++); |
| |
| unsigned BaseRegEnc = getX86RegEncoding(MI, MemOperand + X86::AddrBaseReg); |
| VEX_B = ~(BaseRegEnc >> 3) & 1; |
| unsigned IndexRegEnc = getX86RegEncoding(MI, MemOperand+X86::AddrIndexReg); |
| VEX_X = ~(IndexRegEnc >> 3) & 1; |
| 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), |
| unsigned RegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_R = ~(RegEnc >> 3) & 1; |
| EVEX_R2 = ~(RegEnc >> 4) & 1; |
| |
| if (HasEVEX_K) |
| EVEX_aaa = getX86RegEncoding(MI, CurOp++); |
| |
| if (HasVEX_4V) { |
| unsigned VRegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_4V = ~VRegEnc & 0xf; |
| EVEX_V2 = ~(VRegEnc >> 4) & 1; |
| } |
| |
| if (HasMemOp4) // Skip second register source (encoded in I8IMM) |
| CurOp++; |
| |
| RegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_B = ~(RegEnc >> 3) & 1; |
| VEX_X = ~(RegEnc >> 4) & 1; |
| if (HasVEX_4VOp3) |
| VEX_4V = ~getX86RegEncoding(MI, CurOp++) & 0xf; |
| 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) |
| unsigned RegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_B = ~(RegEnc >> 3) & 1; |
| VEX_X = ~(RegEnc >> 4) & 1; |
| |
| if (HasEVEX_K) |
| EVEX_aaa = getX86RegEncoding(MI, CurOp++); |
| |
| if (HasVEX_4V) { |
| unsigned VRegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_4V = ~VRegEnc & 0xf; |
| EVEX_V2 = ~(VRegEnc >> 4) & 1; |
| } |
| |
| RegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_R = ~(RegEnc >> 3) & 1; |
| EVEX_R2 = ~(RegEnc >> 4) & 1; |
| 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) { |
| unsigned VRegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_4V = ~VRegEnc & 0xf; |
| EVEX_V2 = ~(VRegEnc >> 4) & 1; |
| } |
| if (HasEVEX_K) |
| EVEX_aaa = getX86RegEncoding(MI, CurOp++); |
| |
| unsigned RegEnc = getX86RegEncoding(MI, CurOp++); |
| VEX_B = ~(RegEnc >> 3) & 1; |
| VEX_X = ~(RegEnc >> 4) & 1; |
| 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 | |
| // +-----+ +--------------+ +-------------------+ |
| uint8_t 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!"); |
| |
| 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. |
| uint8_t X86MCCodeEmitter::DetermineREXPrefix(const MCInst &MI, uint64_t TSFlags, |
| int MemOperand, |
| const MCInstrDesc &Desc) const { |
| uint8_t REX = 0; |
| bool UsesHighByteReg = false; |
| |
| if (TSFlags & X86II::REX_W) |
| REX |= 1 << 3; // set REX.W |
| |
| if (MI.getNumOperands() == 0) return REX; |
| |
| unsigned NumOps = MI.getNumOperands(); |
| unsigned CurOp = X86II::getOperandBias(Desc); |
| |
| // If it accesses SPL, BPL, SIL, or DIL, then it requires a 0x40 REX prefix. |
| for (unsigned i = CurOp; i != NumOps; ++i) { |
| const MCOperand &MO = MI.getOperand(i); |
| if (!MO.isReg()) continue; |
| unsigned Reg = MO.getReg(); |
| if (Reg == X86::AH || Reg == X86::BH || Reg == X86::CH || Reg == X86::DH) |
| UsesHighByteReg = true; |
| 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::AddRegFrm: |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 0; // REX.B |
| break; |
| case X86II::MRMSrcReg: |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 2; // REX.R |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 0; // REX.B |
| break; |
| case X86II::MRMSrcMem: { |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 2; // REX.R |
| REX |= isX86_64ExtendedReg(MI, MemOperand+X86::AddrBaseReg) << 0; // REX.B |
| REX |= isX86_64ExtendedReg(MI, MemOperand+X86::AddrIndexReg) << 1; // REX.X |
| CurOp += X86::AddrNumOperands; |
| break; |
| } |
| case X86II::MRMDestReg: |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 0; // REX.B |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 2; // REX.R |
| break; |
| case X86II::MRMDestMem: |
| REX |= isX86_64ExtendedReg(MI, MemOperand+X86::AddrBaseReg) << 0; // REX.B |
| REX |= isX86_64ExtendedReg(MI, MemOperand+X86::AddrIndexReg) << 1; // REX.X |
| CurOp += X86::AddrNumOperands; |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 2; // REX.R |
| 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: |
| REX |= isX86_64ExtendedReg(MI, MemOperand+X86::AddrBaseReg) << 0; // REX.B |
| REX |= isX86_64ExtendedReg(MI, MemOperand+X86::AddrIndexReg) << 1; // REX.X |
| 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: |
| REX |= isX86_64ExtendedReg(MI, CurOp++) << 0; // REX.B |
| break; |
| } |
| if (REX && UsesHighByteReg) |
| report_fatal_error("Cannot encode high byte register in REX-prefixed instruction"); |
| |
| 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 (uint8_t REX = DetermineREXPrefix(MI, TSFlags, MemOperand, 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; |
| bool HasVEX_I8IMM = TSFlags & X86II::VEX_I8IMM; |
| assert((!HasMemOp4 || HasVEX_I8IMM) && "MemOp4 should imply VEX_I8IMM"); |
| |
| // It uses the EVEX.aaa field? |
| bool HasEVEX_K = TSFlags & X86II::EVEX_K; |
| bool HasEVEX_RC = TSFlags & X86II::EVEX_RC; |
| |
| // Used if a register is encoded in 7:4 of immediate. |
| unsigned I8RegNum = 0; |
| |
| // 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); |
| |
| uint8_t BaseOpcode = X86II::getBaseOpcodeFor(TSFlags); |
| |
| if (TSFlags & X86II::Has3DNow0F0FOpcode) |
| BaseOpcode = 0x0F; // Weird 3DNow! encoding. |
| |
| uint64_t Form = TSFlags & X86II::FormMask; |
| switch (Form) { |
| default: errs() << "FORM: " << Form << "\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); |
| unsigned 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); |
| unsigned 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); |
| unsigned SrcRegNum = CurOp + 1; |
| |
| if (HasEVEX_K) // Skip writemask |
| ++SrcRegNum; |
| |
| if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV) |
| ++SrcRegNum; |
| |
| if (HasMemOp4) // Capture 2nd src (which is encoded in I8IMM) |
| I8RegNum = getX86RegEncoding(MI, SrcRegNum++); |
| |
| EmitRegModRMByte(MI.getOperand(SrcRegNum), |
| GetX86RegNum(MI.getOperand(CurOp)), CurByte, OS); |
| CurOp = SrcRegNum + 1; |
| if (HasVEX_4VOp3) |
| ++CurOp; |
| if (!HasMemOp4 && HasVEX_I8IMM) |
| I8RegNum = getX86RegEncoding(MI, CurOp++); |
| // do not count the rounding control operand |
| if (HasEVEX_RC) |
| --NumOps; |
| break; |
| } |
| case X86II::MRMSrcMem: { |
| unsigned FirstMemOp = CurOp+1; |
| |
| if (HasEVEX_K) // Skip writemask |
| ++FirstMemOp; |
| |
| if (HasVEX_4V) |
| ++FirstMemOp; // Skip the register source (which is encoded in VEX_VVVV). |
| |
| if (HasMemOp4) // Capture second register source (encoded in I8IMM) |
| I8RegNum = getX86RegEncoding(MI, FirstMemOp++); |
| |
| EmitByte(BaseOpcode, CurByte, OS); |
| |
| EmitMemModRMByte(MI, FirstMemOp, GetX86RegNum(MI.getOperand(CurOp)), |
| TSFlags, CurByte, OS, Fixups, STI); |
| CurOp = FirstMemOp + X86::AddrNumOperands; |
| if (HasVEX_4VOp3) |
| ++CurOp; |
| if (!HasMemOp4 && HasVEX_I8IMM) |
| I8RegNum = getX86RegEncoding(MI, 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); |
| 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); |
| 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); |
| EmitByte(0xC0 + Form - X86II::MRM_C0, CurByte, OS); |
| break; |
| } |
| |
| if (HasVEX_I8IMM) { |
| // The last source register of a 4 operand instruction in AVX is encoded |
| // in bits[7:4] of a immediate byte. |
| assert(I8RegNum < 16 && "Register encoding out of range"); |
| I8RegNum <<= 4; |
| if (CurOp != NumOps) { |
| unsigned Val = MI.getOperand(CurOp++).getImm(); |
| assert(Val < 16 && "Immediate operand value out of range"); |
| I8RegNum |= Val; |
| } |
| EmitImmediate(MCOperand::createImm(I8RegNum), MI.getLoc(), 1, FK_Data_1, |
| CurByte, OS, Fixups); |
| } else { |
| // 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) { |
| 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 |
| } |