1 //===-- AVRInstrInfo.cpp - AVR Instruction Information --------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains the AVR implementation of the TargetInstrInfo class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "AVRInstrInfo.h" 14 15 #include "llvm/ADT/STLExtras.h" 16 #include "llvm/CodeGen/MachineConstantPool.h" 17 #include "llvm/CodeGen/MachineFrameInfo.h" 18 #include "llvm/CodeGen/MachineInstrBuilder.h" 19 #include "llvm/CodeGen/MachineMemOperand.h" 20 #include "llvm/IR/Constants.h" 21 #include "llvm/IR/Function.h" 22 #include "llvm/MC/MCContext.h" 23 #include "llvm/MC/TargetRegistry.h" 24 #include "llvm/Support/Debug.h" 25 #include "llvm/Support/ErrorHandling.h" 26 27 #include "AVR.h" 28 #include "AVRMachineFunctionInfo.h" 29 #include "AVRRegisterInfo.h" 30 #include "AVRTargetMachine.h" 31 #include "MCTargetDesc/AVRMCTargetDesc.h" 32 33 #define GET_INSTRINFO_CTOR_DTOR 34 #include "AVRGenInstrInfo.inc" 35 36 namespace llvm { 37 38 AVRInstrInfo::AVRInstrInfo() 39 : AVRGenInstrInfo(AVR::ADJCALLSTACKDOWN, AVR::ADJCALLSTACKUP), RI() {} 40 41 void AVRInstrInfo::copyPhysReg(MachineBasicBlock &MBB, 42 MachineBasicBlock::iterator MI, 43 const DebugLoc &DL, MCRegister DestReg, 44 MCRegister SrcReg, bool KillSrc) const { 45 const AVRSubtarget &STI = MBB.getParent()->getSubtarget<AVRSubtarget>(); 46 const AVRRegisterInfo &TRI = *STI.getRegisterInfo(); 47 unsigned Opc; 48 49 // Not all AVR devices support the 16-bit `MOVW` instruction. 50 if (AVR::DREGSRegClass.contains(DestReg, SrcReg)) { 51 if (STI.hasMOVW() && AVR::DREGSMOVWRegClass.contains(DestReg, SrcReg)) { 52 BuildMI(MBB, MI, DL, get(AVR::MOVWRdRr), DestReg) 53 .addReg(SrcReg, getKillRegState(KillSrc)); 54 } else { 55 Register DestLo, DestHi, SrcLo, SrcHi; 56 57 TRI.splitReg(DestReg, DestLo, DestHi); 58 TRI.splitReg(SrcReg, SrcLo, SrcHi); 59 60 // Copy each individual register with the `MOV` instruction. 61 BuildMI(MBB, MI, DL, get(AVR::MOVRdRr), DestLo) 62 .addReg(SrcLo, getKillRegState(KillSrc)); 63 BuildMI(MBB, MI, DL, get(AVR::MOVRdRr), DestHi) 64 .addReg(SrcHi, getKillRegState(KillSrc)); 65 } 66 } else { 67 if (AVR::GPR8RegClass.contains(DestReg, SrcReg)) { 68 Opc = AVR::MOVRdRr; 69 } else if (SrcReg == AVR::SP && AVR::DREGSRegClass.contains(DestReg)) { 70 Opc = AVR::SPREAD; 71 } else if (DestReg == AVR::SP && AVR::DREGSRegClass.contains(SrcReg)) { 72 Opc = AVR::SPWRITE; 73 } else { 74 llvm_unreachable("Impossible reg-to-reg copy"); 75 } 76 77 BuildMI(MBB, MI, DL, get(Opc), DestReg) 78 .addReg(SrcReg, getKillRegState(KillSrc)); 79 } 80 } 81 82 unsigned AVRInstrInfo::isLoadFromStackSlot(const MachineInstr &MI, 83 int &FrameIndex) const { 84 switch (MI.getOpcode()) { 85 case AVR::LDDRdPtrQ: 86 case AVR::LDDWRdYQ: { //: FIXME: remove this once PR13375 gets fixed 87 if (MI.getOperand(1).isFI() && MI.getOperand(2).isImm() && 88 MI.getOperand(2).getImm() == 0) { 89 FrameIndex = MI.getOperand(1).getIndex(); 90 return MI.getOperand(0).getReg(); 91 } 92 break; 93 } 94 default: 95 break; 96 } 97 98 return 0; 99 } 100 101 unsigned AVRInstrInfo::isStoreToStackSlot(const MachineInstr &MI, 102 int &FrameIndex) const { 103 switch (MI.getOpcode()) { 104 case AVR::STDPtrQRr: 105 case AVR::STDWPtrQRr: { 106 if (MI.getOperand(0).isFI() && MI.getOperand(1).isImm() && 107 MI.getOperand(1).getImm() == 0) { 108 FrameIndex = MI.getOperand(0).getIndex(); 109 return MI.getOperand(2).getReg(); 110 } 111 break; 112 } 113 default: 114 break; 115 } 116 117 return 0; 118 } 119 120 void AVRInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB, 121 MachineBasicBlock::iterator MI, 122 Register SrcReg, bool isKill, 123 int FrameIndex, 124 const TargetRegisterClass *RC, 125 const TargetRegisterInfo *TRI) const { 126 MachineFunction &MF = *MBB.getParent(); 127 AVRMachineFunctionInfo *AFI = MF.getInfo<AVRMachineFunctionInfo>(); 128 129 AFI->setHasSpills(true); 130 131 DebugLoc DL; 132 if (MI != MBB.end()) { 133 DL = MI->getDebugLoc(); 134 } 135 136 const MachineFrameInfo &MFI = MF.getFrameInfo(); 137 138 MachineMemOperand *MMO = MF.getMachineMemOperand( 139 MachinePointerInfo::getFixedStack(MF, FrameIndex), 140 MachineMemOperand::MOStore, MFI.getObjectSize(FrameIndex), 141 MFI.getObjectAlign(FrameIndex)); 142 143 unsigned Opcode = 0; 144 if (TRI->isTypeLegalForClass(*RC, MVT::i8)) { 145 Opcode = AVR::STDPtrQRr; 146 } else if (TRI->isTypeLegalForClass(*RC, MVT::i16)) { 147 Opcode = AVR::STDWPtrQRr; 148 } else { 149 llvm_unreachable("Cannot store this register into a stack slot!"); 150 } 151 152 BuildMI(MBB, MI, DL, get(Opcode)) 153 .addFrameIndex(FrameIndex) 154 .addImm(0) 155 .addReg(SrcReg, getKillRegState(isKill)) 156 .addMemOperand(MMO); 157 } 158 159 void AVRInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB, 160 MachineBasicBlock::iterator MI, 161 Register DestReg, int FrameIndex, 162 const TargetRegisterClass *RC, 163 const TargetRegisterInfo *TRI) const { 164 DebugLoc DL; 165 if (MI != MBB.end()) { 166 DL = MI->getDebugLoc(); 167 } 168 169 MachineFunction &MF = *MBB.getParent(); 170 const MachineFrameInfo &MFI = MF.getFrameInfo(); 171 172 MachineMemOperand *MMO = MF.getMachineMemOperand( 173 MachinePointerInfo::getFixedStack(MF, FrameIndex), 174 MachineMemOperand::MOLoad, MFI.getObjectSize(FrameIndex), 175 MFI.getObjectAlign(FrameIndex)); 176 177 unsigned Opcode = 0; 178 if (TRI->isTypeLegalForClass(*RC, MVT::i8)) { 179 Opcode = AVR::LDDRdPtrQ; 180 } else if (TRI->isTypeLegalForClass(*RC, MVT::i16)) { 181 // Opcode = AVR::LDDWRdPtrQ; 182 //: FIXME: remove this once PR13375 gets fixed 183 Opcode = AVR::LDDWRdYQ; 184 } else { 185 llvm_unreachable("Cannot load this register from a stack slot!"); 186 } 187 188 BuildMI(MBB, MI, DL, get(Opcode), DestReg) 189 .addFrameIndex(FrameIndex) 190 .addImm(0) 191 .addMemOperand(MMO); 192 } 193 194 const MCInstrDesc &AVRInstrInfo::getBrCond(AVRCC::CondCodes CC) const { 195 switch (CC) { 196 default: 197 llvm_unreachable("Unknown condition code!"); 198 case AVRCC::COND_EQ: 199 return get(AVR::BREQk); 200 case AVRCC::COND_NE: 201 return get(AVR::BRNEk); 202 case AVRCC::COND_GE: 203 return get(AVR::BRGEk); 204 case AVRCC::COND_LT: 205 return get(AVR::BRLTk); 206 case AVRCC::COND_SH: 207 return get(AVR::BRSHk); 208 case AVRCC::COND_LO: 209 return get(AVR::BRLOk); 210 case AVRCC::COND_MI: 211 return get(AVR::BRMIk); 212 case AVRCC::COND_PL: 213 return get(AVR::BRPLk); 214 } 215 } 216 217 AVRCC::CondCodes AVRInstrInfo::getCondFromBranchOpc(unsigned Opc) const { 218 switch (Opc) { 219 default: 220 return AVRCC::COND_INVALID; 221 case AVR::BREQk: 222 return AVRCC::COND_EQ; 223 case AVR::BRNEk: 224 return AVRCC::COND_NE; 225 case AVR::BRSHk: 226 return AVRCC::COND_SH; 227 case AVR::BRLOk: 228 return AVRCC::COND_LO; 229 case AVR::BRMIk: 230 return AVRCC::COND_MI; 231 case AVR::BRPLk: 232 return AVRCC::COND_PL; 233 case AVR::BRGEk: 234 return AVRCC::COND_GE; 235 case AVR::BRLTk: 236 return AVRCC::COND_LT; 237 } 238 } 239 240 AVRCC::CondCodes AVRInstrInfo::getOppositeCondition(AVRCC::CondCodes CC) const { 241 switch (CC) { 242 default: 243 llvm_unreachable("Invalid condition!"); 244 case AVRCC::COND_EQ: 245 return AVRCC::COND_NE; 246 case AVRCC::COND_NE: 247 return AVRCC::COND_EQ; 248 case AVRCC::COND_SH: 249 return AVRCC::COND_LO; 250 case AVRCC::COND_LO: 251 return AVRCC::COND_SH; 252 case AVRCC::COND_GE: 253 return AVRCC::COND_LT; 254 case AVRCC::COND_LT: 255 return AVRCC::COND_GE; 256 case AVRCC::COND_MI: 257 return AVRCC::COND_PL; 258 case AVRCC::COND_PL: 259 return AVRCC::COND_MI; 260 } 261 } 262 263 bool AVRInstrInfo::analyzeBranch(MachineBasicBlock &MBB, 264 MachineBasicBlock *&TBB, 265 MachineBasicBlock *&FBB, 266 SmallVectorImpl<MachineOperand> &Cond, 267 bool AllowModify) const { 268 // Start from the bottom of the block and work up, examining the 269 // terminator instructions. 270 MachineBasicBlock::iterator I = MBB.end(); 271 MachineBasicBlock::iterator UnCondBrIter = MBB.end(); 272 273 while (I != MBB.begin()) { 274 --I; 275 if (I->isDebugInstr()) { 276 continue; 277 } 278 279 // Working from the bottom, when we see a non-terminator 280 // instruction, we're done. 281 if (!isUnpredicatedTerminator(*I)) { 282 break; 283 } 284 285 // A terminator that isn't a branch can't easily be handled 286 // by this analysis. 287 if (!I->getDesc().isBranch()) { 288 return true; 289 } 290 291 // Handle unconditional branches. 292 //: TODO: add here jmp 293 if (I->getOpcode() == AVR::RJMPk) { 294 UnCondBrIter = I; 295 296 if (!AllowModify) { 297 TBB = I->getOperand(0).getMBB(); 298 continue; 299 } 300 301 // If the block has any instructions after a JMP, delete them. 302 while (std::next(I) != MBB.end()) { 303 std::next(I)->eraseFromParent(); 304 } 305 306 Cond.clear(); 307 FBB = nullptr; 308 309 // Delete the JMP if it's equivalent to a fall-through. 310 if (MBB.isLayoutSuccessor(I->getOperand(0).getMBB())) { 311 TBB = nullptr; 312 I->eraseFromParent(); 313 I = MBB.end(); 314 UnCondBrIter = MBB.end(); 315 continue; 316 } 317 318 // TBB is used to indicate the unconditinal destination. 319 TBB = I->getOperand(0).getMBB(); 320 continue; 321 } 322 323 // Handle conditional branches. 324 AVRCC::CondCodes BranchCode = getCondFromBranchOpc(I->getOpcode()); 325 if (BranchCode == AVRCC::COND_INVALID) { 326 return true; // Can't handle indirect branch. 327 } 328 329 // Working from the bottom, handle the first conditional branch. 330 if (Cond.empty()) { 331 MachineBasicBlock *TargetBB = I->getOperand(0).getMBB(); 332 if (AllowModify && UnCondBrIter != MBB.end() && 333 MBB.isLayoutSuccessor(TargetBB)) { 334 // If we can modify the code and it ends in something like: 335 // 336 // jCC L1 337 // jmp L2 338 // L1: 339 // ... 340 // L2: 341 // 342 // Then we can change this to: 343 // 344 // jnCC L2 345 // L1: 346 // ... 347 // L2: 348 // 349 // Which is a bit more efficient. 350 // We conditionally jump to the fall-through block. 351 BranchCode = getOppositeCondition(BranchCode); 352 unsigned JNCC = getBrCond(BranchCode).getOpcode(); 353 MachineBasicBlock::iterator OldInst = I; 354 355 BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(JNCC)) 356 .addMBB(UnCondBrIter->getOperand(0).getMBB()); 357 BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(AVR::RJMPk)) 358 .addMBB(TargetBB); 359 360 OldInst->eraseFromParent(); 361 UnCondBrIter->eraseFromParent(); 362 363 // Restart the analysis. 364 UnCondBrIter = MBB.end(); 365 I = MBB.end(); 366 continue; 367 } 368 369 FBB = TBB; 370 TBB = I->getOperand(0).getMBB(); 371 Cond.push_back(MachineOperand::CreateImm(BranchCode)); 372 continue; 373 } 374 375 // Handle subsequent conditional branches. Only handle the case where all 376 // conditional branches branch to the same destination. 377 assert(Cond.size() == 1); 378 assert(TBB); 379 380 // Only handle the case where all conditional branches branch to 381 // the same destination. 382 if (TBB != I->getOperand(0).getMBB()) { 383 return true; 384 } 385 386 AVRCC::CondCodes OldBranchCode = (AVRCC::CondCodes)Cond[0].getImm(); 387 // If the conditions are the same, we can leave them alone. 388 if (OldBranchCode == BranchCode) { 389 continue; 390 } 391 392 return true; 393 } 394 395 return false; 396 } 397 398 unsigned AVRInstrInfo::insertBranch(MachineBasicBlock &MBB, 399 MachineBasicBlock *TBB, 400 MachineBasicBlock *FBB, 401 ArrayRef<MachineOperand> Cond, 402 const DebugLoc &DL, int *BytesAdded) const { 403 if (BytesAdded) 404 *BytesAdded = 0; 405 406 // Shouldn't be a fall through. 407 assert(TBB && "insertBranch must not be told to insert a fallthrough"); 408 assert((Cond.size() == 1 || Cond.size() == 0) && 409 "AVR branch conditions have one component!"); 410 411 if (Cond.empty()) { 412 assert(!FBB && "Unconditional branch with multiple successors!"); 413 auto &MI = *BuildMI(&MBB, DL, get(AVR::RJMPk)).addMBB(TBB); 414 if (BytesAdded) 415 *BytesAdded += getInstSizeInBytes(MI); 416 return 1; 417 } 418 419 // Conditional branch. 420 unsigned Count = 0; 421 AVRCC::CondCodes CC = (AVRCC::CondCodes)Cond[0].getImm(); 422 auto &CondMI = *BuildMI(&MBB, DL, getBrCond(CC)).addMBB(TBB); 423 424 if (BytesAdded) 425 *BytesAdded += getInstSizeInBytes(CondMI); 426 ++Count; 427 428 if (FBB) { 429 // Two-way Conditional branch. Insert the second branch. 430 auto &MI = *BuildMI(&MBB, DL, get(AVR::RJMPk)).addMBB(FBB); 431 if (BytesAdded) 432 *BytesAdded += getInstSizeInBytes(MI); 433 ++Count; 434 } 435 436 return Count; 437 } 438 439 unsigned AVRInstrInfo::removeBranch(MachineBasicBlock &MBB, 440 int *BytesRemoved) const { 441 if (BytesRemoved) 442 *BytesRemoved = 0; 443 444 MachineBasicBlock::iterator I = MBB.end(); 445 unsigned Count = 0; 446 447 while (I != MBB.begin()) { 448 --I; 449 if (I->isDebugInstr()) { 450 continue; 451 } 452 //: TODO: add here the missing jmp instructions once they are implemented 453 // like jmp, {e}ijmp, and other cond branches, ... 454 if (I->getOpcode() != AVR::RJMPk && 455 getCondFromBranchOpc(I->getOpcode()) == AVRCC::COND_INVALID) { 456 break; 457 } 458 459 // Remove the branch. 460 if (BytesRemoved) 461 *BytesRemoved += getInstSizeInBytes(*I); 462 I->eraseFromParent(); 463 I = MBB.end(); 464 ++Count; 465 } 466 467 return Count; 468 } 469 470 bool AVRInstrInfo::reverseBranchCondition( 471 SmallVectorImpl<MachineOperand> &Cond) const { 472 assert(Cond.size() == 1 && "Invalid AVR branch condition!"); 473 474 AVRCC::CondCodes CC = static_cast<AVRCC::CondCodes>(Cond[0].getImm()); 475 Cond[0].setImm(getOppositeCondition(CC)); 476 477 return false; 478 } 479 480 unsigned AVRInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const { 481 unsigned Opcode = MI.getOpcode(); 482 483 switch (Opcode) { 484 // A regular instruction 485 default: { 486 const MCInstrDesc &Desc = get(Opcode); 487 return Desc.getSize(); 488 } 489 case TargetOpcode::EH_LABEL: 490 case TargetOpcode::IMPLICIT_DEF: 491 case TargetOpcode::KILL: 492 case TargetOpcode::DBG_VALUE: 493 return 0; 494 case TargetOpcode::INLINEASM: 495 case TargetOpcode::INLINEASM_BR: { 496 const MachineFunction &MF = *MI.getParent()->getParent(); 497 const AVRTargetMachine &TM = 498 static_cast<const AVRTargetMachine &>(MF.getTarget()); 499 const AVRSubtarget &STI = MF.getSubtarget<AVRSubtarget>(); 500 const TargetInstrInfo &TII = *STI.getInstrInfo(); 501 502 return TII.getInlineAsmLength(MI.getOperand(0).getSymbolName(), 503 *TM.getMCAsmInfo()); 504 } 505 } 506 } 507 508 MachineBasicBlock * 509 AVRInstrInfo::getBranchDestBlock(const MachineInstr &MI) const { 510 switch (MI.getOpcode()) { 511 default: 512 llvm_unreachable("unexpected opcode!"); 513 case AVR::JMPk: 514 case AVR::CALLk: 515 case AVR::RCALLk: 516 case AVR::RJMPk: 517 case AVR::BREQk: 518 case AVR::BRNEk: 519 case AVR::BRSHk: 520 case AVR::BRLOk: 521 case AVR::BRMIk: 522 case AVR::BRPLk: 523 case AVR::BRGEk: 524 case AVR::BRLTk: 525 return MI.getOperand(0).getMBB(); 526 case AVR::BRBSsk: 527 case AVR::BRBCsk: 528 return MI.getOperand(1).getMBB(); 529 case AVR::SBRCRrB: 530 case AVR::SBRSRrB: 531 case AVR::SBICAb: 532 case AVR::SBISAb: 533 llvm_unreachable("unimplemented branch instructions"); 534 } 535 } 536 537 bool AVRInstrInfo::isBranchOffsetInRange(unsigned BranchOp, 538 int64_t BrOffset) const { 539 540 switch (BranchOp) { 541 default: 542 llvm_unreachable("unexpected opcode!"); 543 case AVR::JMPk: 544 case AVR::CALLk: 545 return true; 546 case AVR::RCALLk: 547 case AVR::RJMPk: 548 return isIntN(13, BrOffset); 549 case AVR::BRBSsk: 550 case AVR::BRBCsk: 551 case AVR::BREQk: 552 case AVR::BRNEk: 553 case AVR::BRSHk: 554 case AVR::BRLOk: 555 case AVR::BRMIk: 556 case AVR::BRPLk: 557 case AVR::BRGEk: 558 case AVR::BRLTk: 559 return isIntN(7, BrOffset); 560 } 561 } 562 563 void AVRInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB, 564 MachineBasicBlock &NewDestBB, 565 MachineBasicBlock &RestoreBB, 566 const DebugLoc &DL, int64_t BrOffset, 567 RegScavenger *RS) const { 568 // This method inserts a *direct* branch (JMP), despite its name. 569 // LLVM calls this method to fixup unconditional branches; it never calls 570 // insertBranch or some hypothetical "insertDirectBranch". 571 // See lib/CodeGen/RegisterRelaxation.cpp for details. 572 // We end up here when a jump is too long for a RJMP instruction. 573 BuildMI(&MBB, DL, get(AVR::JMPk)).addMBB(&NewDestBB); 574 } 575 576 } // end of namespace llvm 577