//===-- ARM/ARMCodeEmitter.cpp - Convert ARM code to machine code ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the Raul Herbster and 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 "ARMInstrInfo.h"
#include "ARMSubtarget.h"
#include "ARMTargetMachine.h"
#include "ARMRelocations.h"
#include "ARMAddressingModes.h"
#include "ARM.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/Function.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 Emitter : public MachineFunctionPass {
const ARMInstrInfo *II;
const TargetData *TD;
TargetMachine &TM;
MachineCodeEmitter &MCE;
public:
static char ID;
explicit Emitter(TargetMachine &tm, MachineCodeEmitter &mce)
: MachineFunctionPass((intptr_t)&ID), II(0), TD(0), TM(tm),
MCE(mce) {}
Emitter(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);
int getMachineOpValue(const MachineInstr &MI, unsigned OpIndex);
unsigned getBaseOpcodeFor(const TargetInstrDescriptor *TID);
unsigned getBinaryCodeForInstr(const MachineInstr &MI);
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);
private:
int getShiftOp(const MachineOperand &MO);
};
char Emitter::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 Emitter(TM, MCE);
}
bool Emitter::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;
}
/// getBaseOpcodeFor - Return the opcode value
unsigned Emitter::getBaseOpcodeFor(const TargetInstrDescriptor *TID) {
return (TID->TSFlags & ARMII::OpcodeMask) >> ARMII::OpcodeShift;
}
/// getShiftOp - Verify which is the shift opcode (bit[6:5]) of the
/// machine operand.
int Emitter::getShiftOp(const MachineOperand &MO) {
unsigned ShiftOp = 0x0;
switch(ARM_AM::getAM2ShiftOpc(MO.getImmedValue())) {
default: assert(0 && "Unknown shift opc!");
case ARM_AM::asr:
ShiftOp = 0X2;
break;
case ARM_AM::lsl:
ShiftOp = 0X0;
break;
case ARM_AM::lsr:
ShiftOp = 0X1;
break;
case ARM_AM::ror:
case ARM_AM::rrx:
ShiftOp = 0X3;
break;
}
return ShiftOp;
}
int Emitter::getMachineOpValue(const MachineInstr &MI, unsigned OpIndex) {
intptr_t rv = 0;
const MachineOperand &MO = MI.getOperand(OpIndex);
if (MO.isRegister()) {
assert(MRegisterInfo::isPhysicalRegister(MO.getReg()));
rv = ARMRegisterInfo::getRegisterNumbering(MO.getReg());
} else if (MO.isImmediate()) {
rv = MO.getImmedValue();
} 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.getConstantPoolIndex(), ARM::reloc_arm_relative);
} else if (MO.isJumpTableIndex()) {
emitJumpTableAddress(MO.getJumpTableIndex(), ARM::reloc_arm_relative);
} else if (MO.isMachineBasicBlock()) {
emitMachineBasicBlock(MO.getMachineBasicBlock());
}
return rv;
}
/// emitGlobalAddressForCall - Emit the specified address to the code stream
/// assuming this is part of a function call, which is PC relative.
///
void Emitter::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 Emitter::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 Emitter::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 Emitter::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 Emitter::emitMachineBasicBlock(MachineBasicBlock *BB) {
MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
ARM::reloc_arm_branch, BB));
}
void Emitter::emitInstruction(const MachineInstr &MI) {
NumEmitted++; // Keep track of the # of mi's emitted
MCE.emitWordLE(getBinaryCodeForInstr(MI));
}
unsigned Emitter::getBinaryCodeForInstr(const MachineInstr &MI) {
const TargetInstrDescriptor *Desc = MI.getInstrDescriptor();
const unsigned opcode = MI.getOpcode();
// initial instruction mask
unsigned Value = 0xE0000000;
unsigned op;
switch (Desc->TSFlags & ARMII::AddrModeMask) {
case ARMII::AddrModeNone: {
switch(Desc->TSFlags & ARMII::FormMask) {
default: {
assert(0 && "Unknown instruction subtype!");
// treat special instruction CLZ
if(opcode == ARM::CLZ) {
// set first operand
op = getMachineOpValue(MI,0);
Value |= op << ARMII::RegRdShift;
// set second operand
op = getMachineOpValue(MI,1);
Value |= op;
}
break;
}
case ARMII::MulSMLAW:
case ARMII::MulSMULW:
// set bit W(21)
Value |= 1 << 21;
case ARMII::MulSMLA:
case ARMII::MulSMUL: {
// set bit W(21)
Value |= 1 << 24;
// set opcode (bit[7:4]). For more information, see ARM-ARM page A3-31
// SMLA<x><y> - 1yx0
// SMLAW<y> - 1y00
// SMULW<y> - 1y10
// SMUL<x><y> - 1yx0
unsigned char BaseOpcode = getBaseOpcodeFor(Desc);
Value |= BaseOpcode << 4;
unsigned Format = (Desc->TSFlags & ARMII::FormMask);
if (Format == ARMII::MulSMUL)
Value |= 1 << 22;
// set first operand
op = getMachineOpValue(MI,0);
Value |= op << ARMII::RegRnShift;
// set second operand
op = getMachineOpValue(MI,1);
Value |= op;
// set third operand
op = getMachineOpValue(MI,2);
Value |= op << ARMII::RegRsShift;
// instructions SMLA and SMLAW have a fourth operand
if (Format != ARMII::MulSMULW && Format != ARMII::MulSMUL) {
op = getMachineOpValue(MI,3);
Value |= op << ARMII::RegRdShift;
}
break;
}
case ARMII::MulFrm: {
// bit[7:4] is always 9
Value |= 9 << 4;
// set opcode (bit[23:20])
unsigned char BaseOpcode = getBaseOpcodeFor(Desc);
Value |= BaseOpcode << 20;
bool isMUL = opcode == ARM::MUL;
bool isMLA = opcode == ARM::MLA;
// set first operand
op = getMachineOpValue(MI,0);
Value |= op << (isMUL || isMLA ? ARMII::RegRnShift : ARMII::RegRdShift);
// set second operand
op = getMachineOpValue(MI,1);
Value |= op << (isMUL || isMLA ? 0 : ARMII::RegRnShift);
// set third operand
op = getMachineOpValue(MI,2);
Value |= op << (isMUL || isMLA ? ARMII::RegRsShift : 0);
// multiply instructions (except MUL), have a fourth operand
if (!isMUL) {
op = getMachineOpValue(MI,3);
Value |= op << (isMLA ? ARMII::RegRdShift : ARMII::RegRsShift);
}
break;
}
case ARMII::Branch: {
// set opcode (bit[27:24])
unsigned BaseOpcode = getBaseOpcodeFor(Desc);
Value |= BaseOpcode << 24;
// set signed_immed_24 field
op = getMachineOpValue(MI,0);
Value |= op;
// if it is a conditional branch, set cond field
if (opcode == ARM::Bcc) {
op = getMachineOpValue(MI,1);
Value &= 0x0FFFFFFF; // clear conditional field
Value |= op << 28; // set conditional field
}
break;
}
case ARMII::BranchMisc: {
// set opcode (bit[7:4])
unsigned char BaseOpcode = getBaseOpcodeFor(Desc);
Value |= BaseOpcode << 4;
// set bit[27:24] to 1, set bit[23:20] to 2 and set bit[19:8] to 0xFFF
Value |= 0x12fff << 8;
if (opcode == ARM::BX_RET)
op = 0xe; // the return register is LR
else
// otherwise, set the return register
op = getMachineOpValue(MI,0);
Value |= op;
break;
}
case ARMII::Pseudo:
break;
}
break;
}
case ARMII::AddrMode1: {
// set opcode (bit[24:21]) of data-processing instructions
unsigned char BaseOpcode = getBaseOpcodeFor(Desc);
Value |= BaseOpcode << 21;
// treat 3 special instructions: MOVsra_flag, MOVsrl_flag and
// MOVrx.
unsigned Format = (Desc->TSFlags & ARMII::FormMask);
if (Format == ARMII::DPRdMisc) {
Value |= getMachineOpValue(MI,0) << ARMII::RegRdShift;
Value |= getMachineOpValue(MI,1);
switch(opcode) {
case ARM::MOVsra_flag: {
Value |= 0x1 << 6;
Value |= 0x1 << 7;
break;
}
case ARM::MOVsrl_flag: {
Value |= 0x1 << 5;
Value |= 0x1 << 7;
break;
}
case ARM::MOVrx: {
Value |= 0x3 << 5;
break;
}
}
break;
}
// 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;
// set bit S(20)
if (Format == ARMII::DPRImS || Format == ARMII::DPRRegS ||
Format == ARMII::DPRSoRegS || IsDataProcessing2) {
Value |= 1 << ARMII::S_BitShift;
IsDataProcessing3 = !IsDataProcessing2;
}
IsDataProcessing3 = Format == ARMII::DPRIm ||
Format == ARMII::DPRReg ||
Format == ARMII::DPRSoReg ||
IsDataProcessing3;
// set first operand
op = getMachineOpValue(MI,0);
if (IsDataProcessing1 || IsDataProcessing3) {
Value |= op << ARMII::RegRdShift;
} else if (IsDataProcessing2) {
Value |= op << ARMII::RegRnShift;
}
// set second operand of data processing #3 instructions
if (IsDataProcessing3) {
op = getMachineOpValue(MI,1);
Value |= op << ARMII::RegRnShift;
}
unsigned OperandIndex = IsDataProcessing3 ? 2 : 1;
switch (Format) {
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>
Value |= 1 << ARMII::I_BitShift;
// set immed_8 field
const MachineOperand &MO = MI.getOperand(OperandIndex);
op = ARM_AM::getSOImmVal(MO.getImmedValue());
Value |= op;
break;
}
case ARMII::DPRdReg: case ARMII::DPRnReg:
case ARMII::DPRReg: case ARMII::DPRRegS: {
// set last operand (register Rm)
op = getMachineOpValue(MI,OperandIndex);
Value |= op;
break;
}
case ARMII::DPRdSoReg: case ARMII::DPRnSoReg:
case ARMII::DPRSoReg: case ARMII::DPRSoRegS: {
// set last operand (register Rm)
op = getMachineOpValue(MI,OperandIndex);
Value |= op;
const MachineOperand &MO1 = MI.getOperand(OperandIndex + 1);
const MachineOperand &MO2 = MI.getOperand(OperandIndex + 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.getImmedValue())) {
default: assert(0 && "Unknown shift opc!");
case ARM_AM::asr: {
if(IsShiftByRegister)
Value |= 0x5 << 4;
else
Value |= 0x1 << 6;
break;
}
case ARM_AM::lsl: {
if(IsShiftByRegister)
Value |= 0x1 << 4;
break;
}
case ARM_AM::lsr: {
if(IsShiftByRegister)
Value |= 0x3 << 4;
else
Value |= 0x1 << 5;
break;
}
case ARM_AM::ror: {
if(IsShiftByRegister)
Value |= 0x7 << 4;
else
Value |= 0x3 << 5;
break;
}
case ARM_AM::rrx: {
Value |= 0x3 << 5;
break;
}
}
// set the field related to shift operations (except rrx).
if(ARM_AM::getSORegShOp(MO2.getImmedValue()) != ARM_AM::rrx)
if(IsShiftByRegister) {
// set the value of bit[11:8] (register Rs).
assert(MRegisterInfo::isPhysicalRegister(MO1.getReg()));
op = ARMRegisterInfo::getRegisterNumbering(MO1.getReg());
assert(ARM_AM::getSORegOffset(MO2.getImm()) == 0);
Value |= op << ARMII::RegRsShift;
} else {
// set the value of bit [11:7] (shift_immed field).
op = ARM_AM::getSORegOffset(MO2.getImm());
Value |= op << 7;
}
break;
}
default: assert(false && "Unknown operand type!");
break;
}
break;
}
case ARMII::AddrMode2: {
// bit 26 is always 1
Value |= 1 << 26;
unsigned Index = (Desc->TSFlags & ARMII::IndexModeMask);
// if the instruction uses offset addressing or pre-indexed addressing,
// set bit P(24) to 1
if (Index == ARMII::IndexModePre || Index == 0)
Value |= 1 << ARMII::IndexShift;
// if the instruction uses post-indexed addressing, set bit W(21) to 1
if (Index == ARMII::IndexModePre)
Value |= 1 << 21;
unsigned Format = (Desc->TSFlags & ARMII::FormMask);
// If it is a load instruction (except LDRD), set bit L(20) to 1
if (Format == ARMII::LdFrm)
Value |= 1 << ARMII::L_BitShift;
// set bit B(22)
unsigned BitByte = getBaseOpcodeFor(Desc);
Value |= BitByte << 22;
// set first operand
op = getMachineOpValue(MI,0);
Value |= op << ARMII::RegRdShift;
// set second operand
op = getMachineOpValue(MI,1);
Value |= op << 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)
Value |= (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
Value |= ARM_AM::getAM2Offset(MO3.getImm());
break;
}
// set bit I(25), because this is not in immediate enconding.
Value |= 1 << ARMII::I_BitShift;
assert(MRegisterInfo::isPhysicalRegister(MO2.getReg()));
// set bit[3:0] to the corresponding Rm register
Value |= 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())) {
unsigned ShiftOp = getShiftOp(MO3);
Value |= ShiftOp << 5; // shift
Value |= ShImm << 7; // shift_immed
}
break;
}
case ARMII::AddrMode3: {
unsigned Index = (Desc->TSFlags & ARMII::IndexModeMask);
// if the instruction uses offset addressing or pre-indexed addressing,
// set bit P(24) to 1
if (Index == ARMII::IndexModePre || Index == 0)
Value |= 1 << ARMII::IndexShift;
unsigned Format = (Desc->TSFlags & ARMII::FormMask);
// If it is a load instruction (except LDRD), set bit L(20) to 1
if (Format == ARMII::LdFrm && opcode != ARM::LDRD)
Value |= 1 << ARMII::L_BitShift;
// bit[7:4] is the opcode of this instruction class (bits S and H).
unsigned char BaseOpcode = getBaseOpcodeFor(Desc);
Value |= BaseOpcode << 4;
// set first operand
op = getMachineOpValue(MI,0);
Value |= op << ARMII::RegRdShift;
// set second operand
op = getMachineOpValue(MI,1);
Value |= op << 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)
Value |= (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()) {
Value |= ARMRegisterInfo::getRegisterNumbering(MO2.getReg());
break;
}
// if this instr is in immediate offset/index encoding, set bit 22 to 1
if (unsigned ImmOffs = ARM_AM::getAM3Offset(MO3.getImm())) {
Value |= 1 << 22;
// set operands
Value |= (ImmOffs >> 4) << 8; // immedH
Value |= (ImmOffs & ~0xF); // immedL
}
break;
}
case ARMII::AddrMode4: {
// bit 27 is always 1
Value |= 1 << 27;
unsigned Format = (Desc->TSFlags & ARMII::FormMask);
// if it is a load instr, set bit L(20) to 1
if (Format == ARMII::LdFrm)
Value |= 1 << ARMII::L_BitShift;
unsigned OpIndex = 0;
// set first operand
op = getMachineOpValue(MI,OpIndex);
Value |= op << 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(OpIndex + 1);
ARM_AM::AMSubMode Mode = ARM_AM::getAM4SubMode(MO.getImm());
switch(Mode) {
default: assert(0 && "Unknown addressing sub-mode!");
case ARM_AM::ia: Value |= 0x1 << 23; break;
case ARM_AM::ib: Value |= 0x3 << 23; break;
case ARM_AM::da: break;
case ARM_AM::db: Value |= 0x1 << 24; break;
}
// set bit W(21)
if (ARM_AM::getAM4WBFlag(MO.getImm()))
Value |= 0x1 << 21;
// set registers
for (unsigned i = OpIndex + 4, e = MI.getNumOperands(); i != e; ++i) {
const MachineOperand &MOR = MI.getOperand(i);
unsigned RegNumber = ARMRegisterInfo::getRegisterNumbering(MOR.getReg());
assert(MRegisterInfo::isPhysicalRegister(MOR.getReg()) && RegNumber < 16);
Value |= 0x1 << RegNumber;
}
break;
}
}
return Value;
}
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