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llvm-6502/lib/Target/X86/X86MCCodeEmitter.cpp
Chris Lattner 548abfcbd6 Implement support for the bizarre 3DNow! encoding (which is unlike anything 
else in X86), and add support for pavgusb.  This is apparently the
only instruction (other than movsx) that is preventing ffmpeg from building
with clang.

If someone else is interested in banging out the rest of the 3DNow! 
instructions, it should be quite easy now.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115466 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-03 18:08:05 +00:00

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//===-- 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 "x86-emitter"
#include "X86.h"
#include "X86InstrInfo.h"
#include "X86FixupKinds.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.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 TargetMachine &TM;
const TargetInstrInfo &TII;
MCContext &Ctx;
bool Is64BitMode;
public:
X86MCCodeEmitter(TargetMachine &tm, MCContext &ctx, bool is64Bit)
: TM(tm), TII(*TM.getInstrInfo()), Ctx(ctx) {
Is64BitMode = is64Bit;
}
~X86MCCodeEmitter() {}
unsigned getNumFixupKinds() const {
return 6;
}
const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const {
const static MCFixupKindInfo Infos[] = {
{ "reloc_pcrel_4byte", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel },
{ "reloc_pcrel_1byte", 0, 1 * 8, MCFixupKindInfo::FKF_IsPCRel },
{ "reloc_pcrel_2byte", 0, 2 * 8, MCFixupKindInfo::FKF_IsPCRel },
{ "reloc_riprel_4byte", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel },
{ "reloc_riprel_4byte_movq_load", 0, 4 * 8, MCFixupKindInfo::FKF_IsPCRel },
{ "reloc_signed_4byte", 0, 4 * 8, 0}
};
if (Kind < FirstTargetFixupKind)
return MCCodeEmitter::getFixupKindInfo(Kind);
assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
"Invalid kind!");
return Infos[Kind - FirstTargetFixupKind];
}
static unsigned GetX86RegNum(const MCOperand &MO) {
return X86RegisterInfo::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 TargetInstrDesc &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 TargetInstrDesc &Desc,
raw_ostream &OS) const;
};
} // end anonymous namespace
MCCodeEmitter *llvm::createX86_32MCCodeEmitter(const Target &,
TargetMachine &TM,
MCContext &Ctx) {
return new X86MCCodeEmitter(TM, Ctx, false);
}
MCCodeEmitter *llvm::createX86_64MCCodeEmitter(const Target &,
TargetMachine &TM,
MCContext &Ctx) {
return new X86MCCodeEmitter(TM, Ctx, true);
}
/// 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);
switch (Size) {
default: assert(0 && "Unknown immediate size");
case 1: return isPCRel ? MCFixupKind(X86::reloc_pcrel_1byte) : FK_Data_1;
case 2: return isPCRel ? MCFixupKind(X86::reloc_pcrel_2byte) : FK_Data_2;
case 4: return isPCRel ? MCFixupKind(X86::reloc_pcrel_4byte) : FK_Data_4;
case 8: assert(!isPCRel); return FK_Data_8;
}
}
/// 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 && X86::GR32RegClass.contains(BaseReg.getReg())) ||
(IndexReg.getReg() != 0 && X86::GR32RegClass.contains(IndexReg.getReg())))
return true;
return false;
}
void X86MCCodeEmitter::
EmitImmediate(const MCOperand &DispOp, unsigned Size, MCFixupKind FixupKind,
unsigned &CurByte, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups, int ImmOffset) const {
// If this is a simple integer displacement that doesn't require a relocation,
// emit it now.
if (DispOp.isImm()) {
// FIXME: is this right for pc-rel encoding?? Probably need to emit this as
// a fixup if so.
EmitConstant(DispOp.getImm()+ImmOffset, Size, CurByte, OS);
return;
}
// If we have an immoffset, add it to the expression.
const MCExpr *Expr = DispOp.getExpr();
// 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 == MCFixupKind(X86::reloc_pcrel_4byte) ||
FixupKind == MCFixupKind(X86::reloc_riprel_4byte) ||
FixupKind == MCFixupKind(X86::reloc_riprel_4byte_movq_load))
ImmOffset -= 4;
if (FixupKind == MCFixupKind(X86::reloc_pcrel_2byte))
ImmOffset -= 2;
if (FixupKind == MCFixupKind(X86::reloc_pcrel_1byte))
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 ||
MI.getOpcode() == X86::MOV64rm_TC)
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 TargetInstrDesc &Desc,
raw_ostream &OS) const {
bool HasVEX_4V = false;
if ((TSFlags >> 32) & 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 >> 32) & X86II::VEX_W)
VEX_W = 1;
if ((TSFlags >> 32) & 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::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() &&
X86InstrInfo::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 begining
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 >> 32) & X86II::VEX_I8IMM)
NumOps--;
for (; CurOp != NumOps; ++CurOp) {
const MCOperand &MO = MI.getOperand(CurOp);
if (MO.isReg() && X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
VEX_B = 0x0;
if (!VEX_B && MO.isReg() &&
((TSFlags & X86II::FormMask) == X86II::MRMSrcMem) &&
X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
VEX_X = 0x0;
}
break;
default: // MRMDestReg, MRM0r-MRM7r, RawFrm
if (!MI.getNumOperands())
break;
if (MI.getOperand(CurOp).isReg() &&
X86InstrInfo::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 &&
X86InstrInfo::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 TargetInstrDesc &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, TOI::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 (!X86InstrInfo::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() &&
X86InstrInfo::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() && X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
REX |= 1 << 0; // set REX.B
}
break;
case X86II::MRMSrcMem: {
if (MI.getOperand(0).isReg() &&
X86InstrInfo::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 (X86InstrInfo::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() &&
X86InstrInfo::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 (X86InstrInfo::isX86_64ExtendedReg(MO.getReg()))
REX |= 1 << Bit; // REX.B (Bit=0) and REX.X (Bit=1)
Bit++;
}
}
break;
}
default:
if (MI.getOperand(0).isReg() &&
X86InstrInfo::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() && X86InstrInfo::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 TargetInstrDesc &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
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;
}
}
void X86MCCodeEmitter::
EncodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups) const {
unsigned Opcode = MI.getOpcode();
const TargetInstrDesc &Desc = TII.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, TOI::TIED_TO) != -1)
++CurOp;
else if (NumOps > 2 && Desc.getOperandConstraint(NumOps-1, TOI::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 >> 32) & X86II::VEX)
HasVEXPrefix = true;
if ((TSFlags >> 32) & 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 >> 32) & 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;
}
// 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 >> 32) & X86II::VEX_I8IMM) {
const MCOperand &MO = MI.getOperand(CurOp++);
bool IsExtReg =
X86InstrInfo::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;
if (MI.getOpcode() == X86::MOV64ri32 || MI.getOpcode() == X86::MOV64mi32)
FixupKind = X86::reloc_signed_4byte;
else
FixupKind = getImmFixupKind(TSFlags);
EmitImmediate(MI.getOperand(CurOp++),
X86II::getSizeOfImm(TSFlags), MCFixupKind(FixupKind),
CurByte, OS, Fixups);
}
}
if ((TSFlags >> 32) & 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
}
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