| //===-- X86/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. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "mccodeemitter" |
| #include "MCTargetDesc/X86MCTargetDesc.h" |
| #include "MCTargetDesc/X86BaseInfo.h" |
| #include "MCTargetDesc/X86FixupKinds.h" |
| #include "llvm/MC/MCCodeEmitter.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; |
| |
| namespace { |
| class X86MCCodeEmitter : public MCCodeEmitter { |
| X86MCCodeEmitter(const X86MCCodeEmitter &); // DO NOT IMPLEMENT |
| void operator=(const X86MCCodeEmitter &); // DO NOT IMPLEMENT |
| const MCInstrInfo &MCII; |
| const MCSubtargetInfo &STI; |
| MCContext &Ctx; |
| public: |
| X86MCCodeEmitter(const MCInstrInfo &mcii, const MCSubtargetInfo &sti, |
| MCContext &ctx) |
| : MCII(mcii), STI(sti), Ctx(ctx) { |
| } |
| |
| ~X86MCCodeEmitter() {} |
| |
| bool is64BitMode() const { |
| // FIXME: Can tablegen auto-generate this? |
| return (STI.getFeatureBits() & X86::Mode64Bit) != 0; |
| } |
| |
| static unsigned GetX86RegNum(const MCOperand &MO) { |
| return X86_MC::getX86RegNum(MO.getReg()); |
| } |
| |
| // On regular x86, both XMM0-XMM7 and XMM8-XMM15 are encoded in the range |
| // 0-7 and the difference between the 2 groups is given by the REX prefix. |
| // In the VEX prefix, registers are seen sequencially from 0-15 and encoded |
| // in 1's complement form, example: |
| // |
| // ModRM field => XMM9 => 1 |
| // VEX.VVVV => XMM9 => ~9 |
| // |
| // See table 4-35 of Intel AVX Programming Reference for details. |
| static unsigned char getVEXRegisterEncoding(const MCInst &MI, |
| unsigned OpNum) { |
| unsigned SrcReg = MI.getOperand(OpNum).getReg(); |
| unsigned SrcRegNum = GetX86RegNum(MI.getOperand(OpNum)); |
| if ((SrcReg >= X86::XMM8 && SrcReg <= X86::XMM15) || |
| (SrcReg >= X86::YMM8 && SrcReg <= X86::YMM15)) |
| SrcRegNum += 8; |
| |
| // The registers represented through VEX_VVVV should |
| // be encoded in 1's complement form. |
| return (~SrcRegNum) & 0xf; |
| } |
| |
| void EmitByte(unsigned char 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, |
| unsigned ImmSize, MCFixupKind FixupKind, |
| unsigned &CurByte, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups, |
| int ImmOffset = 0) const; |
| |
| inline static unsigned char 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; |
| |
| void EncodeInstruction(const MCInst &MI, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups) const; |
| |
| void EmitVEXOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand, |
| const MCInst &MI, const MCInstrDesc &Desc, |
| raw_ostream &OS) const; |
| |
| void EmitSegmentOverridePrefix(uint64_t TSFlags, unsigned &CurByte, |
| int MemOperand, const MCInst &MI, |
| raw_ostream &OS) const; |
| |
| void EmitOpcodePrefix(uint64_t TSFlags, unsigned &CurByte, int MemOperand, |
| const MCInst &MI, const MCInstrDesc &Desc, |
| raw_ostream &OS) const; |
| }; |
| |
| } // end anonymous namespace |
| |
| |
| MCCodeEmitter *llvm::createX86MCCodeEmitter(const MCInstrInfo &MCII, |
| const MCSubtargetInfo &STI, |
| MCContext &Ctx) { |
| return new X86MCCodeEmitter(MCII, STI, Ctx); |
| } |
| |
| /// isDisp8 - Return true if this signed displacement fits in a 8-bit |
| /// sign-extended field. |
| static bool isDisp8(int Value) { |
| return Value == (signed char)Value; |
| } |
| |
| /// 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); |
| |
| return MCFixup::getKindForSize(Size, isPCRel); |
| } |
| |
| namespace llvm { |
| // FIXME: TableGen this? |
| extern MCRegisterClass X86MCRegisterClasses[]; // In X86GenRegisterInfo.inc. |
| } |
| |
| /// Is32BitMemOperand - Return true if the specified instruction with a memory |
| /// operand should emit the 0x67 prefix byte in 64-bit mode due to 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; |
| return false; |
| } |
| |
| /// StartsWithGlobalOffsetTable - Return true for the simple cases where this |
| /// expression starts with _GLOBAL_OFFSET_TABLE_. This is a needed to support |
| /// PIC on ELF i386 as that symbol is magic. We check only simple case that |
| /// are know to be used: _GLOBAL_OFFSET_TABLE_ by itself or at the start |
| /// of a binary expression. |
| static bool StartsWithGlobalOffsetTable(const MCExpr *Expr) { |
| if (Expr->getKind() == MCExpr::Binary) { |
| const MCBinaryExpr *BE = static_cast<const MCBinaryExpr *>(Expr); |
| Expr = BE->getLHS(); |
| } |
| |
| if (Expr->getKind() != MCExpr::SymbolRef) |
| return false; |
| |
| const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Expr); |
| const MCSymbol &S = Ref->getSymbol(); |
| return S.getName() == "_GLOBAL_OFFSET_TABLE_"; |
| } |
| |
| void X86MCCodeEmitter:: |
| EmitImmediate(const MCOperand &DispOp, unsigned Size, MCFixupKind FixupKind, |
| unsigned &CurByte, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups, int ImmOffset) const { |
| const MCExpr *Expr = NULL; |
| 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 == MCFixupKind(X86::reloc_signed_4byte)) && |
| StartsWithGlobalOffsetTable(Expr)) { |
| assert(ImmOffset == 0); |
| |
| FixupKind = MCFixupKind(X86::reloc_global_offset_table); |
| ImmOffset = CurByte; |
| } |
| |
| // 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)); |
| 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{ |
| 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(); |
| |
| // Handle %rip relative addressing. |
| if (BaseReg == X86::RIP) { // [disp32+RIP] in X86-64 mode |
| assert(is64BitMode() && "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, 4, MCFixupKind(FixupKind), |
| CurByte, OS, Fixups, -ImmSize); |
| return; |
| } |
| |
| unsigned BaseRegNo = BaseReg ? GetX86RegNum(Base) : -1U; |
| |
| // 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() || BaseReg != 0)) { |
| |
| if (BaseReg == 0) { // [disp32] in X86-32 mode |
| EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS); |
| EmitImmediate(Disp, 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() && isDisp8(Disp.getImm())) { |
| EmitByte(ModRMByte(1, RegOpcodeField, BaseRegNo), CurByte, OS); |
| EmitImmediate(Disp, 1, FK_Data_1, CurByte, OS, Fixups); |
| return; |
| } |
| |
| // Otherwise, emit the most general non-SIB encoding: [REG+disp32] |
| EmitByte(ModRMByte(2, RegOpcodeField, BaseRegNo), CurByte, OS); |
| EmitImmediate(Disp, 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; |
| 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 (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 { |
| // Emit the normal disp32 encoding. |
| EmitByte(ModRMByte(2, RegOpcodeField, 4), CurByte, OS); |
| } |
| |
| // Calculate what the SS field value should be... |
| static const unsigned SSTable[] = { ~0, 0, 1, ~0, 2, ~0, ~0, ~0, 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, 1, FK_Data_1, CurByte, OS, Fixups); |
| else if (ForceDisp32 || Disp.getImm() != 0) |
| EmitImmediate(Disp, 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 { |
| bool HasVEX_4V = false; |
| if ((TSFlags >> X86II::VEXShift) & X86II::VEX_4V) |
| HasVEX_4V = true; |
| |
| // 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; |
| |
| // 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 |
| // |
| unsigned char VEX_5M = 0x1; |
| |
| // VEX_4V (VEX vvvv field): a register specifier |
| // (in 1's complement form) or 1111 if unused. |
| unsigned char VEX_4V = 0xf; |
| |
| // VEX_L (Vector Length): |
| // |
| // 0: scalar or 128-bit vector |
| // 1: 256-bit vector |
| // |
| unsigned char VEX_L = 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; |
| |
| // Encode the operand size opcode prefix as needed. |
| if (TSFlags & X86II::OpSize) |
| VEX_PP = 0x01; |
| |
| if ((TSFlags >> X86II::VEXShift) & X86II::VEX_W) |
| VEX_W = 1; |
| |
| if ((TSFlags >> X86II::VEXShift) & X86II::VEX_L) |
| VEX_L = 1; |
| |
| switch (TSFlags & X86II::Op0Mask) { |
| default: assert(0 && "Invalid prefix!"); |
| case X86II::T8: // 0F 38 |
| VEX_5M = 0x2; |
| break; |
| case X86II::TA: // 0F 3A |
| VEX_5M = 0x3; |
| break; |
| case X86II::TF: // F2 0F 38 |
| VEX_PP = 0x3; |
| VEX_5M = 0x2; |
| break; |
| case X86II::XS: // F3 0F |
| VEX_PP = 0x2; |
| break; |
| case X86II::XD: // F2 0F |
| VEX_PP = 0x3; |
| break; |
| case X86II::A6: // Bypass: Not used by VEX |
| case X86II::A7: // Bypass: Not used by VEX |
| case X86II::TB: // Bypass: Not used by VEX |
| case 0: |
| break; // No prefix! |
| } |
| |
| // Set the vector length to 256-bit if YMM0-YMM15 is used |
| for (unsigned i = 0; i != MI.getNumOperands(); ++i) { |
| if (!MI.getOperand(i).isReg()) |
| continue; |
| unsigned SrcReg = MI.getOperand(i).getReg(); |
| if (SrcReg >= X86::YMM0 && SrcReg <= X86::YMM15) |
| VEX_L = 1; |
| } |
| |
| unsigned NumOps = MI.getNumOperands(); |
| unsigned CurOp = 0; |
| bool IsDestMem = false; |
| |
| switch (TSFlags & X86II::FormMask) { |
| case X86II::MRMInitReg: assert(0 && "FIXME: Remove this!"); |
| case X86II::MRMDestMem: |
| IsDestMem = true; |
| // The important info for the VEX prefix is never beyond the address |
| // registers. Don't check beyond that. |
| NumOps = CurOp = X86::AddrNumOperands; |
| 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::MRMSrcMem: |
| case X86II::MRMSrcReg: |
| if (MI.getNumOperands() > CurOp && MI.getOperand(CurOp).isReg() && |
| X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg())) |
| VEX_R = 0x0; |
| CurOp++; |
| |
| if (HasVEX_4V) { |
| VEX_4V = getVEXRegisterEncoding(MI, IsDestMem ? CurOp-1 : CurOp); |
| CurOp++; |
| } |
| |
| // To only check operands before the memory address ones, start |
| // the search from the beginning |
| if (IsDestMem) |
| CurOp = 0; |
| |
| // If the last register should be encoded in the immediate field |
| // do not use any bit from VEX prefix to this register, ignore it |
| if ((TSFlags >> X86II::VEXShift) & X86II::VEX_I8IMM) |
| NumOps--; |
| |
| for (; CurOp != NumOps; ++CurOp) { |
| const MCOperand &MO = MI.getOperand(CurOp); |
| if (MO.isReg() && X86II::isX86_64ExtendedReg(MO.getReg())) |
| VEX_B = 0x0; |
| if (!VEX_B && MO.isReg() && |
| ((TSFlags & X86II::FormMask) == X86II::MRMSrcMem) && |
| X86II::isX86_64ExtendedReg(MO.getReg())) |
| VEX_X = 0x0; |
| } |
| break; |
| default: // MRMDestReg, MRM0r-MRM7r, RawFrm |
| if (!MI.getNumOperands()) |
| break; |
| |
| if (MI.getOperand(CurOp).isReg() && |
| X86II::isX86_64ExtendedReg(MI.getOperand(CurOp).getReg())) |
| VEX_B = 0; |
| |
| if (HasVEX_4V) |
| VEX_4V = getVEXRegisterEncoding(MI, CurOp); |
| |
| CurOp++; |
| for (; CurOp != NumOps; ++CurOp) { |
| const MCOperand &MO = MI.getOperand(CurOp); |
| if (MO.isReg() && !HasVEX_4V && |
| X86II::isX86_64ExtendedReg(MO.getReg())) |
| VEX_R = 0x0; |
| } |
| break; |
| } |
| |
| // Emit segment override opcode prefix as needed. |
| EmitSegmentOverridePrefix(TSFlags, CurByte, MemOperand, MI, OS); |
| |
| // 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 | |
| // +-----+ +-------------------+ |
| // |
| unsigned char LastByte = VEX_PP | (VEX_L << 2) | (VEX_4V << 3); |
| |
| if (VEX_B && VEX_X && !VEX_W && (VEX_5M == 1)) { // 2 byte VEX prefix |
| EmitByte(0xC5, CurByte, OS); |
| EmitByte(LastByte | (VEX_R << 7), CurByte, OS); |
| return; |
| } |
| |
| // 3 byte VEX prefix |
| EmitByte(0xC4, CurByte, OS); |
| EmitByte(VEX_R << 7 | VEX_X << 6 | VEX_B << 5 | VEX_5M, CurByte, OS); |
| EmitByte(LastByte | (VEX_W << 7), 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::MRMInitReg: assert(0 && "FIXME: Remove this!"); |
| 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::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(uint64_t TSFlags, |
| unsigned &CurByte, int MemOperand, |
| const MCInst &MI, |
| raw_ostream &OS) const { |
| switch (TSFlags & X86II::SegOvrMask) { |
| default: assert(0 && "Invalid segment!"); |
| case 0: |
| // No segment override, check for explicit one on memory operand. |
| if (MemOperand != -1) { // If the instruction has a memory operand. |
| switch (MI.getOperand(MemOperand+X86::AddrSegmentReg).getReg()) { |
| default: assert(0 && "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; |
| } |
| } |
| break; |
| case X86II::FS: |
| EmitByte(0x64, CurByte, OS); |
| break; |
| case X86II::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, |
| raw_ostream &OS) const { |
| |
| // Emit the lock opcode prefix as needed. |
| if (TSFlags & X86II::LOCK) |
| EmitByte(0xF0, CurByte, OS); |
| |
| // Emit segment override opcode prefix as needed. |
| EmitSegmentOverridePrefix(TSFlags, CurByte, MemOperand, MI, OS); |
| |
| // Emit the repeat opcode prefix as needed. |
| if ((TSFlags & X86II::Op0Mask) == X86II::REP) |
| EmitByte(0xF3, CurByte, OS); |
| |
| // Emit the address size opcode prefix as needed. |
| if ((TSFlags & X86II::AdSize) || |
| (MemOperand != -1 && is64BitMode() && Is32BitMemOperand(MI, MemOperand))) |
| EmitByte(0x67, CurByte, OS); |
| |
| // Emit the operand size opcode prefix as needed. |
| if (TSFlags & X86II::OpSize) |
| EmitByte(0x66, CurByte, OS); |
| |
| bool Need0FPrefix = false; |
| switch (TSFlags & X86II::Op0Mask) { |
| default: assert(0 && "Invalid prefix!"); |
| case 0: break; // No prefix! |
| case X86II::REP: break; // already handled. |
| case X86II::TB: // Two-byte opcode prefix |
| case X86II::T8: // 0F 38 |
| case X86II::TA: // 0F 3A |
| case X86II::A6: // 0F A6 |
| case X86II::A7: // 0F A7 |
| Need0FPrefix = true; |
| break; |
| case X86II::TF: // F2 0F 38 |
| EmitByte(0xF2, CurByte, OS); |
| Need0FPrefix = true; |
| break; |
| case X86II::XS: // F3 0F |
| EmitByte(0xF3, CurByte, OS); |
| Need0FPrefix = true; |
| break; |
| case X86II::XD: // F2 0F |
| EmitByte(0xF2, CurByte, OS); |
| Need0FPrefix = true; |
| break; |
| case X86II::D8: EmitByte(0xD8, CurByte, OS); break; |
| case X86II::D9: EmitByte(0xD9, CurByte, OS); break; |
| case X86II::DA: EmitByte(0xDA, CurByte, OS); break; |
| case X86II::DB: EmitByte(0xDB, CurByte, OS); break; |
| case X86II::DC: EmitByte(0xDC, CurByte, OS); break; |
| case X86II::DD: EmitByte(0xDD, CurByte, OS); break; |
| case X86II::DE: EmitByte(0xDE, CurByte, OS); break; |
| case X86II::DF: EmitByte(0xDF, CurByte, OS); break; |
| } |
| |
| // Handle REX prefix. |
| // FIXME: Can this come before F2 etc to simplify emission? |
| if (is64BitMode()) { |
| if (unsigned REX = DetermineREXPrefix(MI, TSFlags, Desc)) |
| EmitByte(0x40 | REX, CurByte, OS); |
| } |
| |
| // 0x0F escape code must be emitted just before the opcode. |
| if (Need0FPrefix) |
| EmitByte(0x0F, CurByte, OS); |
| |
| // FIXME: Pull this up into previous switch if REX can be moved earlier. |
| switch (TSFlags & X86II::Op0Mask) { |
| case X86II::TF: // F2 0F 38 |
| case X86II::T8: // 0F 38 |
| EmitByte(0x38, CurByte, OS); |
| break; |
| case X86II::TA: // 0F 3A |
| EmitByte(0x3A, CurByte, OS); |
| break; |
| case X86II::A6: // 0F A6 |
| EmitByte(0xA6, CurByte, OS); |
| break; |
| case X86II::A7: // 0F A7 |
| EmitByte(0xA7, CurByte, OS); |
| break; |
| } |
| } |
| |
| void X86MCCodeEmitter:: |
| EncodeInstruction(const MCInst &MI, raw_ostream &OS, |
| SmallVectorImpl<MCFixup> &Fixups) 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; |
| |
| // If this is a two-address instruction, skip one of the register operands. |
| // FIXME: This should be handled during MCInst lowering. |
| unsigned NumOps = Desc.getNumOperands(); |
| unsigned CurOp = 0; |
| if (NumOps > 1 && Desc.getOperandConstraint(1, MCOI::TIED_TO) != -1) |
| ++CurOp; |
| else if (NumOps > 2 && Desc.getOperandConstraint(NumOps-1, MCOI::TIED_TO)== 0) |
| // Skip the last source operand that is tied_to the dest reg. e.g. LXADD32 |
| --NumOps; |
| |
| // Keep track of the current byte being emitted. |
| unsigned CurByte = 0; |
| |
| // Is this instruction encoded using the AVX VEX prefix? |
| bool HasVEXPrefix = false; |
| |
| // It uses the VEX.VVVV field? |
| bool HasVEX_4V = false; |
| |
| if ((TSFlags >> X86II::VEXShift) & X86II::VEX) |
| HasVEXPrefix = true; |
| if ((TSFlags >> X86II::VEXShift) & X86II::VEX_4V) |
| HasVEX_4V = true; |
| |
| |
| // Determine where the memory operand starts, if present. |
| int MemoryOperand = X86II::getMemoryOperandNo(TSFlags); |
| if (MemoryOperand != -1) MemoryOperand += CurOp; |
| |
| if (!HasVEXPrefix) |
| EmitOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, OS); |
| else |
| EmitVEXOpcodePrefix(TSFlags, CurByte, MemoryOperand, MI, Desc, OS); |
| |
| |
| unsigned char BaseOpcode = X86II::getBaseOpcodeFor(TSFlags); |
| |
| if ((TSFlags >> X86II::VEXShift) & X86II::Has3DNow0F0FOpcode) |
| BaseOpcode = 0x0F; // Weird 3DNow! encoding. |
| |
| unsigned SrcRegNum = 0; |
| switch (TSFlags & X86II::FormMask) { |
| case X86II::MRMInitReg: |
| assert(0 && "FIXME: Remove this form when the JIT moves to MCCodeEmitter!"); |
| default: errs() << "FORM: " << (TSFlags & X86II::FormMask) << "\n"; |
| assert(0 && "Unknown FormMask value in X86MCCodeEmitter!"); |
| case X86II::Pseudo: |
| assert(0 && "Pseudo instruction shouldn't be emitted"); |
| case X86II::RawFrm: |
| EmitByte(BaseOpcode, CurByte, OS); |
| break; |
| |
| case X86II::RawFrmImm8: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitImmediate(MI.getOperand(CurOp++), |
| X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags), |
| CurByte, OS, Fixups); |
| EmitImmediate(MI.getOperand(CurOp++), 1, FK_Data_1, CurByte, OS, Fixups); |
| break; |
| case X86II::RawFrmImm16: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitImmediate(MI.getOperand(CurOp++), |
| X86II::getSizeOfImm(TSFlags), getImmFixupKind(TSFlags), |
| CurByte, OS, Fixups); |
| EmitImmediate(MI.getOperand(CurOp++), 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); |
| EmitRegModRMByte(MI.getOperand(CurOp), |
| GetX86RegNum(MI.getOperand(CurOp+1)), CurByte, OS); |
| CurOp += 2; |
| break; |
| |
| case X86II::MRMDestMem: |
| EmitByte(BaseOpcode, CurByte, OS); |
| SrcRegNum = CurOp + X86::AddrNumOperands; |
| |
| if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV) |
| SrcRegNum++; |
| |
| EmitMemModRMByte(MI, CurOp, |
| GetX86RegNum(MI.getOperand(SrcRegNum)), |
| TSFlags, CurByte, OS, Fixups); |
| CurOp = SrcRegNum + 1; |
| break; |
| |
| case X86II::MRMSrcReg: |
| EmitByte(BaseOpcode, CurByte, OS); |
| SrcRegNum = CurOp + 1; |
| |
| if (HasVEX_4V) // Skip 1st src (which is encoded in VEX_VVVV) |
| SrcRegNum++; |
| |
| EmitRegModRMByte(MI.getOperand(SrcRegNum), |
| GetX86RegNum(MI.getOperand(CurOp)), CurByte, OS); |
| CurOp = SrcRegNum + 1; |
| break; |
| |
| case X86II::MRMSrcMem: { |
| int AddrOperands = X86::AddrNumOperands; |
| unsigned FirstMemOp = CurOp+1; |
| if (HasVEX_4V) { |
| ++AddrOperands; |
| ++FirstMemOp; // Skip the register source (which is encoded in VEX_VVVV). |
| } |
| |
| EmitByte(BaseOpcode, CurByte, OS); |
| |
| EmitMemModRMByte(MI, FirstMemOp, GetX86RegNum(MI.getOperand(CurOp)), |
| TSFlags, CurByte, OS, Fixups); |
| CurOp += AddrOperands + 1; |
| 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: |
| if (HasVEX_4V) // Skip the register dst (which is encoded in VEX_VVVV). |
| CurOp++; |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitRegModRMByte(MI.getOperand(CurOp++), |
| (TSFlags & X86II::FormMask)-X86II::MRM0r, |
| CurByte, OS); |
| 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: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitMemModRMByte(MI, CurOp, (TSFlags & X86II::FormMask)-X86II::MRM0m, |
| TSFlags, CurByte, OS, Fixups); |
| CurOp += X86::AddrNumOperands; |
| break; |
| case X86II::MRM_C1: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xC1, CurByte, OS); |
| break; |
| case X86II::MRM_C2: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xC2, CurByte, OS); |
| break; |
| case X86II::MRM_C3: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xC3, CurByte, OS); |
| break; |
| case X86II::MRM_C4: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xC4, CurByte, OS); |
| break; |
| case X86II::MRM_C8: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xC8, CurByte, OS); |
| break; |
| case X86II::MRM_C9: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xC9, CurByte, OS); |
| break; |
| case X86II::MRM_E8: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xE8, CurByte, OS); |
| break; |
| case X86II::MRM_F0: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xF0, CurByte, OS); |
| break; |
| case X86II::MRM_F8: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xF8, CurByte, OS); |
| break; |
| case X86II::MRM_F9: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xF9, CurByte, OS); |
| break; |
| case X86II::MRM_D0: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xD0, CurByte, OS); |
| break; |
| case X86II::MRM_D1: |
| EmitByte(BaseOpcode, CurByte, OS); |
| EmitByte(0xD1, 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. |
| if (CurOp != NumOps) { |
| // The last source register of a 4 operand instruction in AVX is encoded |
| // in bits[7:4] of a immediate byte, and bits[3:0] are ignored. |
| if ((TSFlags >> X86II::VEXShift) & X86II::VEX_I8IMM) { |
| const MCOperand &MO = MI.getOperand(CurOp++); |
| bool IsExtReg = |
| X86II::isX86_64ExtendedReg(MO.getReg()); |
| unsigned RegNum = (IsExtReg ? (1 << 7) : 0); |
| RegNum |= GetX86RegNum(MO) << 4; |
| EmitImmediate(MCOperand::CreateImm(RegNum), 1, FK_Data_1, CurByte, OS, |
| Fixups); |
| } else { |
| unsigned FixupKind; |
| // FIXME: Is there a better way to know that we need a signed relocation? |
| if (MI.getOpcode() == X86::ADD64ri32 || |
| MI.getOpcode() == X86::MOV64ri32 || |
| MI.getOpcode() == X86::MOV64mi32 || |
| MI.getOpcode() == X86::PUSH64i32) |
| FixupKind = X86::reloc_signed_4byte; |
| else |
| FixupKind = getImmFixupKind(TSFlags); |
| EmitImmediate(MI.getOperand(CurOp++), |
| X86II::getSizeOfImm(TSFlags), MCFixupKind(FixupKind), |
| CurByte, OS, Fixups); |
| } |
| } |
| |
| if ((TSFlags >> X86II::VEXShift) & 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 |
| } |