llvm-6502/lib/Target/ARM/ARMMCCodeEmitter.cpp
Jim Grosbach 3e55612472 First part of refactoring ARM addrmode2 (load/store) instructions to be more
explicit about the operands. Split out the different variants into separate
instructions. This gives us the ability to, among other things, assign
different scheduling itineraries to the variants. rdar://8477752.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117409 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 22:37:02 +00:00

307 lines
10 KiB
C++

//===-- ARM/ARMMCCodeEmitter.cpp - Convert ARM 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 ARMMCCodeEmitter class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "arm-emitter"
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMInstrInfo.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
STATISTIC(MCNumEmitted, "Number of MC instructions emitted");
namespace {
class ARMMCCodeEmitter : public MCCodeEmitter {
ARMMCCodeEmitter(const ARMMCCodeEmitter &); // DO NOT IMPLEMENT
void operator=(const ARMMCCodeEmitter &); // DO NOT IMPLEMENT
const TargetMachine &TM;
const TargetInstrInfo &TII;
MCContext &Ctx;
public:
ARMMCCodeEmitter(TargetMachine &tm, MCContext &ctx)
: TM(tm), TII(*TM.getInstrInfo()), Ctx(ctx) {
}
~ARMMCCodeEmitter() {}
unsigned getMachineSoImmOpValue(unsigned SoImm) const;
// getBinaryCodeForInstr - TableGen'erated function for getting the
// binary encoding for an instruction.
unsigned getBinaryCodeForInstr(const MCInst &MI) const;
/// getMachineOpValue - Return binary encoding of operand. If the machine
/// operand requires relocation, record the relocation and return zero.
unsigned getMachineOpValue(const MCInst &MI,const MCOperand &MO) const;
/// getAddrModeImm12OpValue - Return encoding info for 'reg +/- imm12'
/// operand.
unsigned getAddrModeImm12OpValue(const MCInst &MI, unsigned Op) const;
/// getCCOutOpValue - Return encoding of the 's' bit.
unsigned getCCOutOpValue(const MCInst &MI, unsigned Op) const {
// The operand is either reg0 or CPSR. The 's' bit is encoded as '0' or
// '1' respectively.
return MI.getOperand(Op).getReg() == ARM::CPSR;
}
/// getSOImmOpValue - Return an encoded 12-bit shifted-immediate value.
unsigned getSOImmOpValue(const MCInst &MI, unsigned Op) const {
unsigned SoImm = MI.getOperand(Op).getImm();
int SoImmVal = ARM_AM::getSOImmVal(SoImm);
assert(SoImmVal != -1 && "Not a valid so_imm value!");
// Encode rotate_imm.
unsigned Binary = (ARM_AM::getSOImmValRot((unsigned)SoImmVal) >> 1)
<< ARMII::SoRotImmShift;
// Encode immed_8.
Binary |= ARM_AM::getSOImmValImm((unsigned)SoImmVal);
return Binary;
}
/// getSORegOpValue - Return an encoded so_reg shifted register value.
unsigned getSORegOpValue(const MCInst &MI, unsigned Op) const;
unsigned getRotImmOpValue(const MCInst &MI, unsigned Op) const {
switch (MI.getOperand(Op).getImm()) {
default: assert (0 && "Not a valid rot_imm value!");
case 0: return 0;
case 8: return 1;
case 16: return 2;
case 24: return 3;
}
}
unsigned getImmMinusOneOpValue(const MCInst &MI, unsigned Op) const {
return MI.getOperand(Op).getImm() - 1;
}
unsigned getBitfieldInvertedMaskOpValue(const MCInst &MI, unsigned Op) const;
unsigned getNumFixupKinds() const {
assert(0 && "ARMMCCodeEmitter::getNumFixupKinds() not yet implemented.");
return 0;
}
const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const {
static MCFixupKindInfo rtn;
assert(0 && "ARMMCCodeEmitter::getFixupKindInfo() not yet implemented.");
return rtn;
}
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;
void EncodeInstruction(const MCInst &MI, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups) const;
};
} // end anonymous namespace
MCCodeEmitter *llvm::createARMMCCodeEmitter(const Target &,
TargetMachine &TM,
MCContext &Ctx) {
return new ARMMCCodeEmitter(TM, Ctx);
}
void ARMMCCodeEmitter::
EmitImmediate(const MCOperand &DispOp, unsigned Size, MCFixupKind FixupKind,
unsigned &CurByte, raw_ostream &OS,
SmallVectorImpl<MCFixup> &Fixups, int ImmOffset) const {
assert(0 && "ARMMCCodeEmitter::EmitImmediate() not yet implemented.");
}
/// getMachineOpValue - Return binary encoding of operand. If the machine
/// operand requires relocation, record the relocation and return zero.
unsigned ARMMCCodeEmitter::getMachineOpValue(const MCInst &MI,
const MCOperand &MO) const {
if (MO.isReg()) {
unsigned regno = getARMRegisterNumbering(MO.getReg());
// Q registers are encodes as 2x their register number.
switch (MO.getReg()) {
case ARM::Q0: case ARM::Q1: case ARM::Q2: case ARM::Q3:
case ARM::Q4: case ARM::Q5: case ARM::Q6: case ARM::Q7:
case ARM::Q8: case ARM::Q9: case ARM::Q10: case ARM::Q11:
case ARM::Q12: case ARM::Q13: case ARM::Q14: case ARM::Q15:
return 2 * regno;
default:
return regno;
}
} else if (MO.isImm()) {
return static_cast<unsigned>(MO.getImm());
} else if (MO.isFPImm()) {
return static_cast<unsigned>(APFloat(MO.getFPImm())
.bitcastToAPInt().getHiBits(32).getLimitedValue());
} else {
#ifndef NDEBUG
errs() << MO;
#endif
llvm_unreachable(0);
}
return 0;
}
/// getAddrModeImm12OpValue - Return encoding info for 'reg +/- imm12'
/// operand.
unsigned ARMMCCodeEmitter::getAddrModeImm12OpValue(const MCInst &MI,
unsigned OpIdx) const {
// {17-13} = reg
// {12} = (U)nsigned (add == '1', sub == '0')
// {11-0} = imm12
const MCOperand &MO = MI.getOperand(OpIdx);
const MCOperand &MO1 = MI.getOperand(OpIdx + 1);
unsigned Reg = getARMRegisterNumbering(MO.getReg());
int32_t Imm12 = MO1.getImm();
uint32_t Binary;
Binary = Imm12 & 0xfff;
if (Imm12 >= 0)
Binary |= (1 << 12);
Binary |= (Reg << 13);
return Binary;
}
unsigned ARMMCCodeEmitter::getSORegOpValue(const MCInst &MI,
unsigned OpIdx) const {
// Sub-operands are [reg, reg, imm]. The first register is Rm, the reg
// to be shifted. The second is either Rs, the amount to shift by, or
// reg0 in which case the imm contains the amount to shift by.
// {3-0} = Rm.
// {4} = 1 if reg shift, 0 if imm shift
// {6-5} = type
// If reg shift:
// {7} = 0
// {11-8} = Rs
// else (imm shift)
// {11-7} = imm
const MCOperand &MO = MI.getOperand(OpIdx);
const MCOperand &MO1 = MI.getOperand(OpIdx + 1);
const MCOperand &MO2 = MI.getOperand(OpIdx + 2);
ARM_AM::ShiftOpc SOpc = ARM_AM::getSORegShOp(MO2.getImm());
// Encode Rm.
unsigned Binary = getARMRegisterNumbering(MO.getReg());
// Encode the shift opcode.
unsigned SBits = 0;
unsigned Rs = MO1.getReg();
if (Rs) {
// Set shift operand (bit[7:4]).
// LSL - 0001
// LSR - 0011
// ASR - 0101
// ROR - 0111
// RRX - 0110 and bit[11:8] clear.
switch (SOpc) {
default: llvm_unreachable("Unknown shift opc!");
case ARM_AM::lsl: SBits = 0x1; break;
case ARM_AM::lsr: SBits = 0x3; break;
case ARM_AM::asr: SBits = 0x5; break;
case ARM_AM::ror: SBits = 0x7; break;
case ARM_AM::rrx: SBits = 0x6; break;
}
} else {
// Set shift operand (bit[6:4]).
// LSL - 000
// LSR - 010
// ASR - 100
// ROR - 110
switch (SOpc) {
default: llvm_unreachable("Unknown shift opc!");
case ARM_AM::lsl: SBits = 0x0; break;
case ARM_AM::lsr: SBits = 0x2; break;
case ARM_AM::asr: SBits = 0x4; break;
case ARM_AM::ror: SBits = 0x6; break;
}
}
Binary |= SBits << 4;
if (SOpc == ARM_AM::rrx)
return Binary;
// Encode the shift operation Rs or shift_imm (except rrx).
if (Rs) {
// Encode Rs bit[11:8].
assert(ARM_AM::getSORegOffset(MO2.getImm()) == 0);
return Binary | (getARMRegisterNumbering(Rs) << ARMII::RegRsShift);
}
// Encode shift_imm bit[11:7].
return Binary | ARM_AM::getSORegOffset(MO2.getImm()) << 7;
}
unsigned ARMMCCodeEmitter::getBitfieldInvertedMaskOpValue(const MCInst &MI,
unsigned Op) const {
// 10 bits. lower 5 bits are are the lsb of the mask, high five bits are the
// msb of the mask.
const MCOperand &MO = MI.getOperand(Op);
uint32_t v = ~MO.getImm();
uint32_t lsb = CountTrailingZeros_32(v);
uint32_t msb = (32 - CountLeadingZeros_32 (v)) - 1;
assert (v != 0 && lsb < 32 && msb < 32 && "Illegal bitfield mask!");
return lsb | (msb << 5);
}
void ARMMCCodeEmitter::
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;
// Keep track of the current byte being emitted.
unsigned CurByte = 0;
// Pseudo instructions don't get encoded.
if ((TSFlags & ARMII::FormMask) == ARMII::Pseudo)
return;
++MCNumEmitted; // Keep track of the # of mi's emitted
unsigned Value = getBinaryCodeForInstr(MI);
switch (Opcode) {
default: break;
}
EmitConstant(Value, 4, CurByte, OS);
}
// FIXME: These #defines shouldn't be necessary. Instead, tblgen should
// be able to generate code emitter helpers for either variant, like it
// does for the AsmWriter.
#define ARMCodeEmitter ARMMCCodeEmitter
#define MachineInstr MCInst
#include "ARMGenCodeEmitter.inc"
#undef ARMCodeEmitter
#undef MachineInstr