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llvm-6502/lib/Target/ARM/ARMCodeEmitter.cpp
Evan Cheng 7602e11c32 Revamp ARM JIT. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55624 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-02 06:52:38 +00:00

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//===-- ARM/ARMCodeEmitter.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 contains the pass that transforms the ARM machine instructions into
// relocatable machine code.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "arm-emitter"
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMInstrInfo.h"
#include "ARMRelocations.h"
#include "ARMSubtarget.h"
#include "ARMTargetMachine.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Compiler.h"
using namespace llvm;
STATISTIC(NumEmitted, "Number of machine instructions emitted");
namespace {
class VISIBILITY_HIDDEN ARMCodeEmitter : public MachineFunctionPass {
const ARMInstrInfo *II;
const TargetData *TD;
TargetMachine &TM;
MachineCodeEmitter &MCE;
public:
static char ID;
explicit ARMCodeEmitter(TargetMachine &tm, MachineCodeEmitter &mce)
: MachineFunctionPass((intptr_t)&ID), II(0), TD(0), TM(tm),
MCE(mce) {}
ARMCodeEmitter(TargetMachine &tm, MachineCodeEmitter &mce,
const ARMInstrInfo &ii, const TargetData &td)
: MachineFunctionPass((intptr_t)&ID), II(&ii), TD(&td), TM(tm),
MCE(mce) {}
bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const {
return "ARM Machine Code Emitter";
}
void emitInstruction(const MachineInstr &MI);
private:
unsigned getAddrModeNoneInstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary) ;
unsigned getAddrMode1InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary);
unsigned getAddrMode2InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary);
unsigned getAddrMode3InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary);
unsigned getAddrMode4InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary);
/// getInstrBinary - Return binary encoding for the specified
/// machine instruction.
unsigned getInstrBinary(const MachineInstr &MI);
/// getBinaryCodeForInstr - This function, generated by the
/// CodeEmitterGenerator using TableGen, produces the binary encoding for
/// machine instructions.
///
unsigned getBinaryCodeForInstr(const MachineInstr &MI);
/// getMachineOpValue - Return binary encoding of operand. If the machine
/// operand requires relocation, record the relocation and return zero.
unsigned getMachineOpValue(const MachineInstr &MI, unsigned OpIdx) {
return getMachineOpValue(MI, MI.getOperand(OpIdx));
}
unsigned getMachineOpValue(const MachineInstr &MI,
const MachineOperand &MO);
/// getBaseOpcodeFor - Return the opcode value.
///
unsigned getBaseOpcodeFor(const TargetInstrDesc &TID) const {
return (TID.TSFlags & ARMII::OpcodeMask) >> ARMII::OpcodeShift;
}
/// getShiftOp - Return the shift opcode (bit[6:5]) of the machine operand.
///
unsigned getShiftOp(const MachineOperand &MO) const ;
/// Routines that handle operands which add machine relocations which are
/// fixed up by the JIT fixup stage.
void emitGlobalAddressForCall(GlobalValue *GV, bool DoesntNeedStub);
void emitExternalSymbolAddress(const char *ES, unsigned Reloc);
void emitConstPoolAddress(unsigned CPI, unsigned Reloc,
int Disp = 0, unsigned PCAdj = 0 );
void emitJumpTableAddress(unsigned JTI, unsigned Reloc,
unsigned PCAdj = 0);
void emitGlobalConstant(const Constant *CV);
void emitMachineBasicBlock(MachineBasicBlock *BB);
};
char ARMCodeEmitter::ID = 0;
}
/// createARMCodeEmitterPass - Return a pass that emits the collected ARM code
/// to the specified MCE object.
FunctionPass *llvm::createARMCodeEmitterPass(ARMTargetMachine &TM,
MachineCodeEmitter &MCE) {
return new ARMCodeEmitter(TM, MCE);
}
bool ARMCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
MF.getTarget().getRelocationModel() != Reloc::Static) &&
"JIT relocation model must be set to static or default!");
II = ((ARMTargetMachine&)MF.getTarget()).getInstrInfo();
TD = ((ARMTargetMachine&)MF.getTarget()).getTargetData();
do {
MCE.startFunction(MF);
for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
MBB != E; ++MBB) {
MCE.StartMachineBasicBlock(MBB);
for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
I != E; ++I)
emitInstruction(*I);
}
} while (MCE.finishFunction(MF));
return false;
}
/// getShiftOp - Return the shift opcode (bit[6:5]) of the machine operand.
///
unsigned ARMCodeEmitter::getShiftOp(const MachineOperand &MO) const {
switch (ARM_AM::getAM2ShiftOpc(MO.getImm())) {
default: assert(0 && "Unknown shift opc!");
case ARM_AM::asr: return 2;
case ARM_AM::lsl: return 0;
case ARM_AM::lsr: return 1;
case ARM_AM::ror:
case ARM_AM::rrx: return 3;
}
return 0;
}
/// getMachineOpValue - Return binary encoding of operand. If the machine
/// operand requires relocation, record the relocation and return zero.
unsigned ARMCodeEmitter::getMachineOpValue(const MachineInstr &MI,
const MachineOperand &MO) {
if (MO.isRegister())
return ARMRegisterInfo::getRegisterNumbering(MO.getReg());
else if (MO.isImmediate())
return static_cast<unsigned>(MO.getImm());
else if (MO.isGlobalAddress())
emitGlobalAddressForCall(MO.getGlobal(), false);
else if (MO.isExternalSymbol())
emitExternalSymbolAddress(MO.getSymbolName(), ARM::reloc_arm_relative);
else if (MO.isConstantPoolIndex())
emitConstPoolAddress(MO.getIndex(), ARM::reloc_arm_relative);
else if (MO.isJumpTableIndex())
emitJumpTableAddress(MO.getIndex(), ARM::reloc_arm_relative);
else if (MO.isMachineBasicBlock())
emitMachineBasicBlock(MO.getMBB());
abort();
return 0;
}
/// emitGlobalAddressForCall - Emit the specified address to the code stream
/// assuming this is part of a function call, which is PC relative.
///
void ARMCodeEmitter::emitGlobalAddressForCall(GlobalValue *GV,
bool DoesntNeedStub) {
MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(),
ARM::reloc_arm_branch, GV, 0,
DoesntNeedStub));
}
/// emitExternalSymbolAddress - Arrange for the address of an external symbol to
/// be emitted to the current location in the function, and allow it to be PC
/// relative.
void ARMCodeEmitter::emitExternalSymbolAddress(const char *ES, unsigned Reloc) {
MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
Reloc, ES));
}
/// emitConstPoolAddress - Arrange for the address of an constant pool
/// to be emitted to the current location in the function, and allow it to be PC
/// relative.
void ARMCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc,
int Disp /* = 0 */,
unsigned PCAdj /* = 0 */) {
MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
Reloc, CPI, PCAdj));
}
/// emitJumpTableAddress - Arrange for the address of a jump table to
/// be emitted to the current location in the function, and allow it to be PC
/// relative.
void ARMCodeEmitter::emitJumpTableAddress(unsigned JTI, unsigned Reloc,
unsigned PCAdj /* = 0 */) {
MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
Reloc, JTI, PCAdj));
}
/// emitMachineBasicBlock - Emit the specified address basic block.
void ARMCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB) {
MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
ARM::reloc_arm_branch, BB));
}
void ARMCodeEmitter::emitInstruction(const MachineInstr &MI) {
NumEmitted++; // Keep track of the # of mi's emitted
MCE.emitWordLE(getInstrBinary(MI));
}
unsigned ARMCodeEmitter::getAddrModeNoneInstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary) {
switch (Desc.TSFlags & ARMII::FormMask) {
default:
assert(0 && "Unknown instruction subtype!");
break;
case ARMII::Branch: {
// Set signed_immed_24 field
Binary |= getMachineOpValue(MI, 0);
// if it is a conditional branch, set cond field
if (Desc.Opcode == ARM::Bcc) {
Binary &= 0x0FFFFFFF; // clear conditional field
Binary |= getMachineOpValue(MI, 1) << 28; // set conditional field
}
break;
}
case ARMII::BranchMisc: {
// Set bit[19:8] to 0xFFF
Binary |= 0xfff << 8;
if (Desc.Opcode == ARM::BX_RET)
Binary |= 0xe; // the return register is LR
else
// otherwise, set the return register
Binary |= getMachineOpValue(MI, 0);
break;
}
}
return Binary;
}
unsigned ARMCodeEmitter::getAddrMode1InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary) {
// FIXME: Clean up.
// Treat 3 special instructions: MOVsra_flag, MOVsrl_flag and MOVrx.
unsigned Format = Desc.TSFlags & ARMII::FormMask;
if (Format == ARMII::DPRdMisc) {
Binary |= getMachineOpValue(MI, 0) << ARMII::RegRdShift;
Binary |= getMachineOpValue(MI, 1);
switch (Desc.Opcode) {
case ARM::MOVsra_flag:
Binary |= 0x1 << 6;
Binary |= 0x1 << 7;
break;
case ARM::MOVsrl_flag:
Binary |= 0x1 << 5;
Binary |= 0x1 << 7;
break;
case ARM::MOVrx:
Binary |= 0x3 << 5;
break;
}
return Binary;
}
// FIXME: Clean up this part.
// Data processing operand instructions has 3 possible encodings (for more
// information, see ARM-ARM page A3-10):
// 1. <instr> <Rd>,<shifter_operand>
// 2. <instr> <Rn>,<shifter_operand>
// 3. <instr> <Rd>,<Rn>,<shifter_operand>
bool IsDataProcessing1 = Format == ARMII::DPRdIm ||
Format == ARMII::DPRdReg ||
Format == ARMII::DPRdSoReg;
bool IsDataProcessing2 = Format == ARMII::DPRnIm ||
Format == ARMII::DPRnReg ||
Format == ARMII::DPRnSoReg;
bool IsDataProcessing3 = false;
if (Format == ARMII::DPRImS || Format == ARMII::DPRRegS ||
Format == ARMII::DPRSoRegS || IsDataProcessing2)
IsDataProcessing3 = !IsDataProcessing2;
IsDataProcessing3 = Format == ARMII::DPRIm ||
Format == ARMII::DPRReg ||
Format == ARMII::DPRSoReg ||
IsDataProcessing3;
// Set first operand
if (IsDataProcessing1 || IsDataProcessing3) {
Binary |= getMachineOpValue(MI, 0) << ARMII::RegRdShift;
} else if (IsDataProcessing2) {
Binary |= getMachineOpValue(MI, 0) << ARMII::RegRnShift;
}
// Set second operand of data processing #3 instructions
if (IsDataProcessing3)
Binary |= getMachineOpValue(MI, 1) << ARMII::RegRnShift;
unsigned OpIdx = IsDataProcessing3 ? 2 : 1;
switch (Format) {
default:
assert(false && "Unknown operand type!");
break;
case ARMII::DPRdIm: case ARMII::DPRnIm:
case ARMII::DPRIm: case ARMII::DPRImS: {
// Set bit I(25) to identify this is the immediate form of <shifter_op>
Binary |= 1 << ARMII::I_BitShift;
// Set immed_8 field
const MachineOperand &MO = MI.getOperand(OpIdx);
Binary |= ARM_AM::getSOImmVal(MO.getImm());
break;
}
case ARMII::DPRdReg: case ARMII::DPRnReg:
case ARMII::DPRReg: case ARMII::DPRRegS: {
// Set last operand (register Rm)
Binary |= getMachineOpValue(MI, OpIdx);
break;
}
case ARMII::DPRdSoReg: case ARMII::DPRnSoReg:
case ARMII::DPRSoReg: case ARMII::DPRSoRegS: {
// Set last operand (register Rm)
Binary |= getMachineOpValue(MI, OpIdx);
const MachineOperand &MO1 = MI.getOperand(OpIdx + 1);
const MachineOperand &MO2 = MI.getOperand(OpIdx + 2);
// Identify it the instr is in immed or register shifts encoding
bool IsShiftByRegister = MO1.getReg() > 0;
// Set shift operand (bit[6:4]).
// ASR - 101 if it is in register shifts encoding; 100, otherwise.
// LSL - 001 if it is in register shifts encoding; 000, otherwise.
// LSR - 011 if it is in register shifts encoding; 010, otherwise.
// ROR - 111 if it is in register shifts encoding; 110, otherwise.
// RRX - 110 and bit[11:7] clear.
switch (ARM_AM::getSORegShOp(MO2.getImm())) {
default: assert(0 && "Unknown shift opc!");
case ARM_AM::asr:
if (IsShiftByRegister)
Binary |= 0x5 << 4;
else
Binary |= 0x1 << 6;
break;
case ARM_AM::lsl:
if (IsShiftByRegister)
Binary |= 0x1 << 4;
break;
case ARM_AM::lsr:
if (IsShiftByRegister)
Binary |= 0x3 << 4;
else
Binary |= 0x1 << 5;
break;
case ARM_AM::ror:
if (IsShiftByRegister)
Binary |= 0x7 << 4;
else
Binary |= 0x3 << 5;
break;
case ARM_AM::rrx:
Binary |= 0x3 << 5;
break;
}
// Set the field related to shift operations (except rrx).
if (ARM_AM::getSORegShOp(MO2.getImm()) != ARM_AM::rrx) {
if (IsShiftByRegister) {
// Set the value of bit[11:8] (register Rs).
assert(ARM_AM::getSORegOffset(MO2.getImm()) == 0);
Binary |= (ARMRegisterInfo::getRegisterNumbering(MO1.getReg()) <<
ARMII::RegRsShift);
} else
// Set the value of bit [11:7] (shift_immed field).
Binary |= ARM_AM::getSORegOffset(MO2.getImm()) << 7;
}
break;
}
}
return Binary;
}
unsigned ARMCodeEmitter::getAddrMode2InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary) {
// Set first operand
Binary |= getMachineOpValue(MI, 0) << ARMII::RegRdShift;
// Set second operand
Binary |= getMachineOpValue(MI, 1) << ARMII::RegRnShift;
const MachineOperand &MO2 = MI.getOperand(2);
const MachineOperand &MO3 = MI.getOperand(3);
// Set bit U(23) according to signal of immed value (positive or negative).
Binary |= ((ARM_AM::getAM2Op(MO3.getImm()) == ARM_AM::add ? 1 : 0) <<
ARMII::U_BitShift);
if (!MO2.getReg()) { // is immediate
if (ARM_AM::getAM2Offset(MO3.getImm()))
// Set the value of offset_12 field
Binary |= ARM_AM::getAM2Offset(MO3.getImm());
return Binary;
}
// Set bit I(25), because this is not in immediate enconding.
Binary |= 1 << ARMII::I_BitShift;
assert(TargetRegisterInfo::isPhysicalRegister(MO2.getReg()));
// Set bit[3:0] to the corresponding Rm register
Binary |= ARMRegisterInfo::getRegisterNumbering(MO2.getReg());
// if this instr is in scaled register offset/index instruction, set
// shift_immed(bit[11:7]) and shift(bit[6:5]) fields.
if (unsigned ShImm = ARM_AM::getAM2Offset(MO3.getImm())) {
Binary |= getShiftOp(MO3) << 5; // shift
Binary |= ShImm << 7; // shift_immed
}
return Binary;
}
unsigned ARMCodeEmitter::getAddrMode3InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary) {
// Set first operand
Binary |= getMachineOpValue(MI, 0) << ARMII::RegRdShift;
// Set second operand
Binary |= getMachineOpValue(MI, 1) << ARMII::RegRnShift;
const MachineOperand &MO2 = MI.getOperand(2);
const MachineOperand &MO3 = MI.getOperand(3);
// Set bit U(23) according to signal of immed value (positive or negative)
Binary |= ((ARM_AM::getAM2Op(MO3.getImm()) == ARM_AM::add ? 1 : 0) <<
ARMII::U_BitShift);
// If this instr is in register offset/index encoding, set bit[3:0]
// to the corresponding Rm register.
if (MO2.getReg()) {
Binary |= ARMRegisterInfo::getRegisterNumbering(MO2.getReg());
return Binary;
}
// if this instr is in immediate offset/index encoding, set bit 22 to 1
if (unsigned ImmOffs = ARM_AM::getAM3Offset(MO3.getImm())) {
Binary |= 1 << 22;
// Set operands
Binary |= (ImmOffs >> 4) << 8; // immedH
Binary |= (ImmOffs & ~0xF); // immedL
}
return Binary;
}
unsigned ARMCodeEmitter::getAddrMode4InstrBinary(const MachineInstr &MI,
const TargetInstrDesc &Desc,
unsigned Binary) {
// Set first operand
Binary |= getMachineOpValue(MI, 0) << ARMII::RegRnShift;
// Set addressing mode by modifying bits U(23) and P(24)
// IA - Increment after - bit U = 1 and bit P = 0
// IB - Increment before - bit U = 1 and bit P = 1
// DA - Decrement after - bit U = 0 and bit P = 0
// DB - Decrement before - bit U = 0 and bit P = 1
const MachineOperand &MO = MI.getOperand(1);
ARM_AM::AMSubMode Mode = ARM_AM::getAM4SubMode(MO.getImm());
switch (Mode) {
default: assert(0 && "Unknown addressing sub-mode!");
case ARM_AM::da: break;
case ARM_AM::db: Binary |= 0x1 << 24; break;
case ARM_AM::ia: Binary |= 0x1 << 23; break;
case ARM_AM::ib: Binary |= 0x3 << 23; break;
}
// Set bit W(21)
if (ARM_AM::getAM4WBFlag(MO.getImm()))
Binary |= 0x1 << 21;
// Set registers
for (unsigned i = 4, e = MI.getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI.getOperand(i);
if (MO.isRegister() && MO.isImplicit())
continue;
unsigned RegNum = ARMRegisterInfo::getRegisterNumbering(MO.getReg());
assert(TargetRegisterInfo::isPhysicalRegister(MO.getReg()) &&
RegNum < 16);
Binary |= 0x1 << RegNum;
}
return Binary;
}
/// getInstrBinary - Return binary encoding for the specified
/// machine instruction.
unsigned ARMCodeEmitter::getInstrBinary(const MachineInstr &MI) {
// Part of binary is determined by TableGn.
unsigned Binary = getBinaryCodeForInstr(MI);
const TargetInstrDesc &Desc = MI.getDesc();
switch (Desc.TSFlags & ARMII::AddrModeMask) {
case ARMII::AddrModeNone:
return getAddrModeNoneInstrBinary(MI, Desc, Binary);
case ARMII::AddrMode1:
return getAddrMode1InstrBinary(MI, Desc, Binary);
case ARMII::AddrMode2:
return getAddrMode2InstrBinary(MI, Desc, Binary);
case ARMII::AddrMode3:
return getAddrMode3InstrBinary(MI, Desc, Binary);
case ARMII::AddrMode4:
return getAddrMode4InstrBinary(MI, Desc, Binary);
}
abort();
return 0;
}
#include "ARMGenCodeEmitter.inc"
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