ARMCodeEmitter.cpp revision cbefa59743c85da7ff0df234c49e44f9a951e195
1//===-- ARM/ARMCodeEmitter.cpp - Convert ARM code to machine code ---------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file contains the pass that transforms the ARM machine instructions into 11// relocatable machine code. 12// 13//===----------------------------------------------------------------------===// 14 15#define DEBUG_TYPE "arm-emitter" 16#include "ARM.h" 17#include "ARMAddressingModes.h" 18#include "ARMInstrInfo.h" 19#include "ARMRelocations.h" 20#include "ARMSubtarget.h" 21#include "ARMTargetMachine.h" 22#include "llvm/Function.h" 23#include "llvm/PassManager.h" 24#include "llvm/CodeGen/MachineCodeEmitter.h" 25#include "llvm/CodeGen/MachineFunctionPass.h" 26#include "llvm/CodeGen/MachineInstr.h" 27#include "llvm/CodeGen/Passes.h" 28#include "llvm/ADT/Statistic.h" 29#include "llvm/Support/Compiler.h" 30#include "llvm/Support/Debug.h" 31using namespace llvm; 32 33STATISTIC(NumEmitted, "Number of machine instructions emitted"); 34 35namespace { 36 class VISIBILITY_HIDDEN ARMCodeEmitter : public MachineFunctionPass { 37 const ARMInstrInfo *II; 38 const TargetData *TD; 39 TargetMachine &TM; 40 MachineCodeEmitter &MCE; 41 public: 42 static char ID; 43 explicit ARMCodeEmitter(TargetMachine &tm, MachineCodeEmitter &mce) 44 : MachineFunctionPass(&ID), II(0), TD(0), TM(tm), 45 MCE(mce) {} 46 ARMCodeEmitter(TargetMachine &tm, MachineCodeEmitter &mce, 47 const ARMInstrInfo &ii, const TargetData &td) 48 : MachineFunctionPass(&ID), II(&ii), TD(&td), TM(tm), 49 MCE(mce) {} 50 51 bool runOnMachineFunction(MachineFunction &MF); 52 53 virtual const char *getPassName() const { 54 return "ARM Machine Code Emitter"; 55 } 56 57 void emitInstruction(const MachineInstr &MI); 58 59 private: 60 unsigned getAddrModeNoneInstrBinary(const MachineInstr &MI, 61 const TargetInstrDesc &TID, 62 unsigned Binary); 63 64 unsigned getMachineSoRegOpValue(const MachineInstr &MI, 65 const TargetInstrDesc &TID, 66 unsigned OpIdx); 67 68 unsigned getAddrMode1SBit(const MachineInstr &MI, 69 const TargetInstrDesc &TID) const; 70 71 unsigned getAddrMode1InstrBinary(const MachineInstr &MI, 72 const TargetInstrDesc &TID, 73 unsigned Binary); 74 unsigned getAddrMode2InstrBinary(const MachineInstr &MI, 75 const TargetInstrDesc &TID, 76 unsigned Binary); 77 unsigned getAddrMode3InstrBinary(const MachineInstr &MI, 78 const TargetInstrDesc &TID, 79 unsigned Binary); 80 unsigned getAddrMode4InstrBinary(const MachineInstr &MI, 81 const TargetInstrDesc &TID, 82 unsigned Binary); 83 84 /// getInstrBinary - Return binary encoding for the specified 85 /// machine instruction. 86 unsigned getInstrBinary(const MachineInstr &MI); 87 88 /// getBinaryCodeForInstr - This function, generated by the 89 /// CodeEmitterGenerator using TableGen, produces the binary encoding for 90 /// machine instructions. 91 /// 92 unsigned getBinaryCodeForInstr(const MachineInstr &MI); 93 94 /// getMachineOpValue - Return binary encoding of operand. If the machine 95 /// operand requires relocation, record the relocation and return zero. 96 unsigned getMachineOpValue(const MachineInstr &MI, unsigned OpIdx) { 97 return getMachineOpValue(MI, MI.getOperand(OpIdx)); 98 } 99 unsigned getMachineOpValue(const MachineInstr &MI, 100 const MachineOperand &MO); 101 102 /// getBaseOpcodeFor - Return the opcode value. 103 /// 104 unsigned getBaseOpcodeFor(const TargetInstrDesc &TID) const { 105 return (TID.TSFlags & ARMII::OpcodeMask) >> ARMII::OpcodeShift; 106 } 107 108 /// getShiftOp - Return the shift opcode (bit[6:5]) of the machine operand. 109 /// 110 unsigned getShiftOp(const MachineOperand &MO) const ; 111 112 /// Routines that handle operands which add machine relocations which are 113 /// fixed up by the JIT fixup stage. 114 void emitGlobalAddressForCall(GlobalValue *GV, bool DoesntNeedStub); 115 void emitExternalSymbolAddress(const char *ES, unsigned Reloc); 116 void emitConstPoolAddress(unsigned CPI, unsigned Reloc, 117 int Disp = 0, unsigned PCAdj = 0 ); 118 void emitJumpTableAddress(unsigned JTI, unsigned Reloc, 119 unsigned PCAdj = 0); 120 void emitGlobalConstant(const Constant *CV); 121 void emitMachineBasicBlock(MachineBasicBlock *BB); 122 }; 123 char ARMCodeEmitter::ID = 0; 124} 125 126/// createARMCodeEmitterPass - Return a pass that emits the collected ARM code 127/// to the specified MCE object. 128FunctionPass *llvm::createARMCodeEmitterPass(ARMTargetMachine &TM, 129 MachineCodeEmitter &MCE) { 130 return new ARMCodeEmitter(TM, MCE); 131} 132 133bool ARMCodeEmitter::runOnMachineFunction(MachineFunction &MF) { 134 assert((MF.getTarget().getRelocationModel() != Reloc::Default || 135 MF.getTarget().getRelocationModel() != Reloc::Static) && 136 "JIT relocation model must be set to static or default!"); 137 II = ((ARMTargetMachine&)MF.getTarget()).getInstrInfo(); 138 TD = ((ARMTargetMachine&)MF.getTarget()).getTargetData(); 139 140 do { 141 DOUT << "JITTing function '" << MF.getFunction()->getName() << "'\n"; 142 MCE.startFunction(MF); 143 for (MachineFunction::iterator MBB = MF.begin(), E = MF.end(); 144 MBB != E; ++MBB) { 145 MCE.StartMachineBasicBlock(MBB); 146 for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end(); 147 I != E; ++I) 148 emitInstruction(*I); 149 } 150 } while (MCE.finishFunction(MF)); 151 152 return false; 153} 154 155/// getShiftOp - Return the shift opcode (bit[6:5]) of the machine operand. 156/// 157unsigned ARMCodeEmitter::getShiftOp(const MachineOperand &MO) const { 158 switch (ARM_AM::getAM2ShiftOpc(MO.getImm())) { 159 default: assert(0 && "Unknown shift opc!"); 160 case ARM_AM::asr: return 2; 161 case ARM_AM::lsl: return 0; 162 case ARM_AM::lsr: return 1; 163 case ARM_AM::ror: 164 case ARM_AM::rrx: return 3; 165 } 166 return 0; 167} 168 169/// getMachineOpValue - Return binary encoding of operand. If the machine 170/// operand requires relocation, record the relocation and return zero. 171unsigned ARMCodeEmitter::getMachineOpValue(const MachineInstr &MI, 172 const MachineOperand &MO) { 173 if (MO.isRegister()) 174 return ARMRegisterInfo::getRegisterNumbering(MO.getReg()); 175 else if (MO.isImmediate()) 176 return static_cast<unsigned>(MO.getImm()); 177 else if (MO.isGlobalAddress()) 178 emitGlobalAddressForCall(MO.getGlobal(), false); 179 else if (MO.isExternalSymbol()) 180 emitExternalSymbolAddress(MO.getSymbolName(), ARM::reloc_arm_relative); 181 else if (MO.isConstantPoolIndex()) 182 emitConstPoolAddress(MO.getIndex(), ARM::reloc_arm_relative); 183 else if (MO.isJumpTableIndex()) 184 emitJumpTableAddress(MO.getIndex(), ARM::reloc_arm_relative); 185 else if (MO.isMachineBasicBlock()) 186 emitMachineBasicBlock(MO.getMBB()); 187 188 abort(); 189 return 0; 190} 191 192/// emitGlobalAddressForCall - Emit the specified address to the code stream 193/// assuming this is part of a function call, which is PC relative. 194/// 195void ARMCodeEmitter::emitGlobalAddressForCall(GlobalValue *GV, 196 bool DoesntNeedStub) { 197 MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), 198 ARM::reloc_arm_branch, GV, 0, 199 DoesntNeedStub)); 200} 201 202/// emitExternalSymbolAddress - Arrange for the address of an external symbol to 203/// be emitted to the current location in the function, and allow it to be PC 204/// relative. 205void ARMCodeEmitter::emitExternalSymbolAddress(const char *ES, unsigned Reloc) { 206 MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(), 207 Reloc, ES)); 208} 209 210/// emitConstPoolAddress - Arrange for the address of an constant pool 211/// to be emitted to the current location in the function, and allow it to be PC 212/// relative. 213void ARMCodeEmitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc, 214 int Disp /* = 0 */, 215 unsigned PCAdj /* = 0 */) { 216 MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(), 217 Reloc, CPI, PCAdj)); 218} 219 220/// emitJumpTableAddress - Arrange for the address of a jump table to 221/// be emitted to the current location in the function, and allow it to be PC 222/// relative. 223void ARMCodeEmitter::emitJumpTableAddress(unsigned JTI, unsigned Reloc, 224 unsigned PCAdj /* = 0 */) { 225 MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(), 226 Reloc, JTI, PCAdj)); 227} 228 229/// emitMachineBasicBlock - Emit the specified address basic block. 230void ARMCodeEmitter::emitMachineBasicBlock(MachineBasicBlock *BB) { 231 MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(), 232 ARM::reloc_arm_branch, BB)); 233} 234 235void ARMCodeEmitter::emitInstruction(const MachineInstr &MI) { 236 DOUT << MI; 237 238 NumEmitted++; // Keep track of the # of mi's emitted 239 MCE.emitWordLE(getInstrBinary(MI)); 240} 241 242unsigned ARMCodeEmitter::getAddrModeNoneInstrBinary(const MachineInstr &MI, 243 const TargetInstrDesc &TID, 244 unsigned Binary) { 245 switch (TID.TSFlags & ARMII::FormMask) { 246 default: 247 assert(0 && "Unknown instruction subtype!"); 248 break; 249 case ARMII::Branch: { 250 // Set signed_immed_24 field 251 Binary |= getMachineOpValue(MI, 0); 252 253 // if it is a conditional branch, set cond field 254 if (TID.Opcode == ARM::Bcc) { 255 Binary &= 0x0FFFFFFF; // clear conditional field 256 Binary |= getMachineOpValue(MI, 1) << 28; // set conditional field 257 } 258 break; 259 } 260 case ARMII::BranchMisc: { 261 // Set bit[19:8] to 0xFFF 262 Binary |= 0xfff << 8; 263 if (TID.Opcode == ARM::BX_RET) 264 Binary |= 0xe; // the return register is LR 265 else 266 // otherwise, set the return register 267 Binary |= getMachineOpValue(MI, 0); 268 break; 269 } 270 } 271 272 return Binary; 273} 274 275unsigned ARMCodeEmitter::getMachineSoRegOpValue(const MachineInstr &MI, 276 const TargetInstrDesc &TID, 277 unsigned OpIdx) { 278 // Set last operand (register Rm) 279 unsigned Binary = getMachineOpValue(MI, OpIdx); 280 281 const MachineOperand &MO1 = MI.getOperand(OpIdx + 1); 282 const MachineOperand &MO2 = MI.getOperand(OpIdx + 2); 283 ARM_AM::ShiftOpc SOpc = ARM_AM::getSORegShOp(MO2.getImm()); 284 285 // Encode the shift opcode. 286 unsigned SBits = 0; 287 unsigned Rs = MO1.getReg(); 288 if (Rs) { 289 // Set shift operand (bit[7:4]). 290 // LSL - 0001 291 // LSR - 0011 292 // ASR - 0101 293 // ROR - 0111 294 // RRX - 0110 and bit[11:8] clear. 295 switch (SOpc) { 296 default: assert(0 && "Unknown shift opc!"); 297 case ARM_AM::lsl: SBits = 0x1; break; 298 case ARM_AM::lsr: SBits = 0x3; break; 299 case ARM_AM::asr: SBits = 0x5; break; 300 case ARM_AM::ror: SBits = 0x7; break; 301 case ARM_AM::rrx: SBits = 0x6; break; 302 } 303 } else { 304 // Set shift operand (bit[6:4]). 305 // LSL - 000 306 // LSR - 010 307 // ASR - 100 308 // ROR - 110 309 switch (SOpc) { 310 default: assert(0 && "Unknown shift opc!"); 311 case ARM_AM::lsl: SBits = 0x0; break; 312 case ARM_AM::lsr: SBits = 0x2; break; 313 case ARM_AM::asr: SBits = 0x4; break; 314 case ARM_AM::ror: SBits = 0x6; break; 315 } 316 } 317 Binary |= SBits << 4; 318 if (SOpc == ARM_AM::rrx) 319 return Binary; 320 321 // Encode the shift operation Rs or shift_imm (except rrx). 322 if (Rs) { 323 // Encode Rs bit[11:8]. 324 assert(ARM_AM::getSORegOffset(MO2.getImm()) == 0); 325 return Binary | 326 (ARMRegisterInfo::getRegisterNumbering(Rs) << ARMII::RegRsShift); 327 } 328 329 // Encode shift_imm bit[11:7]. 330 return Binary | ARM_AM::getSORegOffset(MO2.getImm()) << 7; 331} 332 333unsigned ARMCodeEmitter::getAddrMode1SBit(const MachineInstr &MI, 334 const TargetInstrDesc &TID) const { 335 for (unsigned i = MI.getNumOperands(), e = TID.getNumOperands(); i != e; --i){ 336 const MachineOperand &MO = MI.getOperand(i-1); 337 if (MO.isRegister() && MO.isDef() && MO.getReg() == ARM::CPSR) 338 return 1 << ARMII::S_BitShift; 339 } 340 return 0; 341} 342 343unsigned ARMCodeEmitter::getAddrMode1InstrBinary(const MachineInstr &MI, 344 const TargetInstrDesc &TID, 345 unsigned Binary) { 346 unsigned Format = TID.TSFlags & ARMII::FormMask; 347 if (Format == ARMII::Pseudo) 348 abort(); // FIXME 349 350 // Encode S bit if MI modifies CPSR. 351 Binary |= getAddrMode1SBit(MI, TID); 352 353 // Encode register def if there is one. 354 unsigned NumDefs = TID.getNumDefs(); 355 unsigned OpIdx = 0; 356 if (NumDefs) { 357 Binary |= getMachineOpValue(MI, OpIdx) << ARMII::RegRdShift; 358 ++OpIdx; 359 } 360 361 // Encode first non-shifter register operand if ther is one. 362 bool isUnary = (Format == ARMII::DPRdMisc || 363 Format == ARMII::DPRdIm || 364 Format == ARMII::DPRdReg || 365 Format == ARMII::DPRdSoReg || 366 Format == ARMII::DPRnIm || 367 Format == ARMII::DPRnReg || 368 Format == ARMII::DPRnSoReg); 369 if (!isUnary) { 370 Binary |= getMachineOpValue(MI, OpIdx) << ARMII::RegRnShift; 371 ++OpIdx; 372 } 373 374 // Encode shifter operand. 375 bool HasSoReg = (Format == ARMII::DPRdSoReg || 376 Format == ARMII::DPRnSoReg || 377 Format == ARMII::DPRSoReg || 378 Format == ARMII::DPRSoRegS); 379 if (HasSoReg) 380 // Encode SoReg. 381 return Binary | getMachineSoRegOpValue(MI, TID, OpIdx); 382 383 const MachineOperand &MO = MI.getOperand(OpIdx); 384 if (MO.isRegister()) 385 // Encode register Rm. 386 return Binary | getMachineOpValue(MI, NumDefs + 1); 387 388 // Encode so_imm. 389 // Set bit I(25) to identify this is the immediate form of <shifter_op> 390 Binary |= 1 << ARMII::I_BitShift; 391 unsigned SoImm = MO.getImm(); 392 // Encode rotate_imm. 393 Binary |= ARM_AM::getSOImmValRot(SoImm) << ARMII::RotImmShift; 394 // Encode immed_8. 395 Binary |= ARM_AM::getSOImmVal(SoImm); 396 return Binary; 397} 398 399unsigned ARMCodeEmitter::getAddrMode2InstrBinary(const MachineInstr &MI, 400 const TargetInstrDesc &TID, 401 unsigned Binary) { 402 // Set first operand 403 Binary |= getMachineOpValue(MI, 0) << ARMII::RegRdShift; 404 405 // Set second operand 406 Binary |= getMachineOpValue(MI, 1) << ARMII::RegRnShift; 407 408 const MachineOperand &MO2 = MI.getOperand(2); 409 const MachineOperand &MO3 = MI.getOperand(3); 410 411 // Set bit U(23) according to signal of immed value (positive or negative). 412 Binary |= ((ARM_AM::getAM2Op(MO3.getImm()) == ARM_AM::add ? 1 : 0) << 413 ARMII::U_BitShift); 414 if (!MO2.getReg()) { // is immediate 415 if (ARM_AM::getAM2Offset(MO3.getImm())) 416 // Set the value of offset_12 field 417 Binary |= ARM_AM::getAM2Offset(MO3.getImm()); 418 return Binary; 419 } 420 421 // Set bit I(25), because this is not in immediate enconding. 422 Binary |= 1 << ARMII::I_BitShift; 423 assert(TargetRegisterInfo::isPhysicalRegister(MO2.getReg())); 424 // Set bit[3:0] to the corresponding Rm register 425 Binary |= ARMRegisterInfo::getRegisterNumbering(MO2.getReg()); 426 427 // if this instr is in scaled register offset/index instruction, set 428 // shift_immed(bit[11:7]) and shift(bit[6:5]) fields. 429 if (unsigned ShImm = ARM_AM::getAM2Offset(MO3.getImm())) { 430 Binary |= getShiftOp(MO3) << 5; // shift 431 Binary |= ShImm << 7; // shift_immed 432 } 433 434 return Binary; 435} 436 437unsigned ARMCodeEmitter::getAddrMode3InstrBinary(const MachineInstr &MI, 438 const TargetInstrDesc &TID, 439 unsigned Binary) { 440 // Set first operand 441 Binary |= getMachineOpValue(MI, 0) << ARMII::RegRdShift; 442 443 // Set second operand 444 Binary |= getMachineOpValue(MI, 1) << ARMII::RegRnShift; 445 446 const MachineOperand &MO2 = MI.getOperand(2); 447 const MachineOperand &MO3 = MI.getOperand(3); 448 449 // Set bit U(23) according to signal of immed value (positive or negative) 450 Binary |= ((ARM_AM::getAM2Op(MO3.getImm()) == ARM_AM::add ? 1 : 0) << 451 ARMII::U_BitShift); 452 453 // If this instr is in register offset/index encoding, set bit[3:0] 454 // to the corresponding Rm register. 455 if (MO2.getReg()) { 456 Binary |= ARMRegisterInfo::getRegisterNumbering(MO2.getReg()); 457 return Binary; 458 } 459 460 // if this instr is in immediate offset/index encoding, set bit 22 to 1 461 if (unsigned ImmOffs = ARM_AM::getAM3Offset(MO3.getImm())) { 462 Binary |= 1 << 22; 463 // Set operands 464 Binary |= (ImmOffs >> 4) << 8; // immedH 465 Binary |= (ImmOffs & ~0xF); // immedL 466 } 467 468 return Binary; 469} 470 471unsigned ARMCodeEmitter::getAddrMode4InstrBinary(const MachineInstr &MI, 472 const TargetInstrDesc &TID, 473 unsigned Binary) { 474 // Set first operand 475 Binary |= getMachineOpValue(MI, 0) << ARMII::RegRnShift; 476 477 // Set addressing mode by modifying bits U(23) and P(24) 478 // IA - Increment after - bit U = 1 and bit P = 0 479 // IB - Increment before - bit U = 1 and bit P = 1 480 // DA - Decrement after - bit U = 0 and bit P = 0 481 // DB - Decrement before - bit U = 0 and bit P = 1 482 const MachineOperand &MO = MI.getOperand(1); 483 ARM_AM::AMSubMode Mode = ARM_AM::getAM4SubMode(MO.getImm()); 484 switch (Mode) { 485 default: assert(0 && "Unknown addressing sub-mode!"); 486 case ARM_AM::da: break; 487 case ARM_AM::db: Binary |= 0x1 << 24; break; 488 case ARM_AM::ia: Binary |= 0x1 << 23; break; 489 case ARM_AM::ib: Binary |= 0x3 << 23; break; 490 } 491 492 // Set bit W(21) 493 if (ARM_AM::getAM4WBFlag(MO.getImm())) 494 Binary |= 0x1 << 21; 495 496 // Set registers 497 for (unsigned i = 4, e = MI.getNumOperands(); i != e; ++i) { 498 const MachineOperand &MO = MI.getOperand(i); 499 if (MO.isRegister() && MO.isImplicit()) 500 continue; 501 unsigned RegNum = ARMRegisterInfo::getRegisterNumbering(MO.getReg()); 502 assert(TargetRegisterInfo::isPhysicalRegister(MO.getReg()) && 503 RegNum < 16); 504 Binary |= 0x1 << RegNum; 505 } 506 507 return Binary; 508} 509 510/// getInstrBinary - Return binary encoding for the specified 511/// machine instruction. 512unsigned ARMCodeEmitter::getInstrBinary(const MachineInstr &MI) { 513 // Part of binary is determined by TableGn. 514 unsigned Binary = getBinaryCodeForInstr(MI); 515 516 const TargetInstrDesc &TID = MI.getDesc(); 517 switch (TID.TSFlags & ARMII::AddrModeMask) { 518 case ARMII::AddrModeNone: 519 return getAddrModeNoneInstrBinary(MI, TID, Binary); 520 case ARMII::AddrMode1: 521 return getAddrMode1InstrBinary(MI, TID, Binary); 522 case ARMII::AddrMode2: 523 return getAddrMode2InstrBinary(MI, TID, Binary); 524 case ARMII::AddrMode3: 525 return getAddrMode3InstrBinary(MI, TID, Binary); 526 case ARMII::AddrMode4: 527 return getAddrMode4InstrBinary(MI, TID, Binary); 528 } 529 530 abort(); 531 return 0; 532} 533 534#include "ARMGenCodeEmitter.inc" 535