//===-- 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 "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 TargetInstrDesc &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 TargetInstrDesc &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.getImm())) { 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(TargetRegisterInfo::isPhysicalRegister(MO.getReg())); rv = ARMRegisterInfo::getRegisterNumbering(MO.getReg()); } else if (MO.isImmediate()) { rv = 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()); } 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 TargetInstrDesc &Desc = MI.getDesc(); unsigned opcode = Desc.Opcode; // 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 - 1yx0 // SMLAW - 1y00 // SMULW - 1y10 // SMUL - 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. , // 2. , // 3. ,, 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 Value |= 1 << ARMII::I_BitShift; // set immed_8 field const MachineOperand &MO = MI.getOperand(OperandIndex); op = ARM_AM::getSOImmVal(MO.getImm()); 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.getImm())) { 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.getImm()) != ARM_AM::rrx) if(IsShiftByRegister) { // set the value of bit[11:8] (register Rs). assert(TargetRegisterInfo::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(TargetRegisterInfo::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(TargetRegisterInfo::isPhysicalRegister(MOR.getReg()) && RegNumber < 16); Value |= 0x1 << RegNumber; } break; } } return Value; }