MachineVerifier.cpp revision 62679fb6f8f1555afc9617e05301e5feb0b8dd7e
1//===-- MachineVerifier.cpp - Machine Code Verifier -------------*- C++ -*-===// 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// Pass to verify generated machine code. The following is checked: 11// 12// Operand counts: All explicit operands must be present. 13// 14// Register classes: All physical and virtual register operands must be 15// compatible with the register class required by the instruction descriptor. 16// 17// Register live intervals: Registers must be defined only once, and must be 18// defined before use. 19// 20// The machine code verifier is enabled from LLVMTargetMachine.cpp with the 21// command-line option -verify-machineinstrs, or by defining the environment 22// variable LLVM_VERIFY_MACHINEINSTRS to the name of a file that will receive 23// the verifier errors. 24//===----------------------------------------------------------------------===// 25 26#include "llvm/Function.h" 27#include "llvm/CodeGen/LiveVariables.h" 28#include "llvm/CodeGen/MachineFunctionPass.h" 29#include "llvm/CodeGen/MachineFrameInfo.h" 30#include "llvm/CodeGen/MachineMemOperand.h" 31#include "llvm/CodeGen/MachineRegisterInfo.h" 32#include "llvm/CodeGen/Passes.h" 33#include "llvm/Target/TargetMachine.h" 34#include "llvm/Target/TargetRegisterInfo.h" 35#include "llvm/Target/TargetInstrInfo.h" 36#include "llvm/ADT/DenseSet.h" 37#include "llvm/ADT/SetOperations.h" 38#include "llvm/ADT/SmallVector.h" 39#include "llvm/Support/Debug.h" 40#include "llvm/Support/ErrorHandling.h" 41#include "llvm/Support/raw_ostream.h" 42using namespace llvm; 43 44namespace { 45 struct MachineVerifier { 46 47 MachineVerifier(Pass *pass, bool allowDoubleDefs) : 48 PASS(pass), 49 allowVirtDoubleDefs(allowDoubleDefs), 50 allowPhysDoubleDefs(true), 51 OutFileName(getenv("LLVM_VERIFY_MACHINEINSTRS")) 52 {} 53 54 bool runOnMachineFunction(MachineFunction &MF); 55 56 Pass *const PASS; 57 const bool allowVirtDoubleDefs; 58 const bool allowPhysDoubleDefs; 59 60 const char *const OutFileName; 61 raw_ostream *OS; 62 const MachineFunction *MF; 63 const TargetMachine *TM; 64 const TargetRegisterInfo *TRI; 65 const MachineRegisterInfo *MRI; 66 67 unsigned foundErrors; 68 69 typedef SmallVector<unsigned, 16> RegVector; 70 typedef DenseSet<unsigned> RegSet; 71 typedef DenseMap<unsigned, const MachineInstr*> RegMap; 72 73 BitVector regsReserved; 74 RegSet regsLive; 75 RegVector regsDefined, regsDead, regsKilled; 76 RegSet regsLiveInButUnused; 77 78 // Add Reg and any sub-registers to RV 79 void addRegWithSubRegs(RegVector &RV, unsigned Reg) { 80 RV.push_back(Reg); 81 if (TargetRegisterInfo::isPhysicalRegister(Reg)) 82 for (const unsigned *R = TRI->getSubRegisters(Reg); *R; R++) 83 RV.push_back(*R); 84 } 85 86 struct BBInfo { 87 // Is this MBB reachable from the MF entry point? 88 bool reachable; 89 90 // Vregs that must be live in because they are used without being 91 // defined. Map value is the user. 92 RegMap vregsLiveIn; 93 94 // Vregs that must be dead in because they are defined without being 95 // killed first. Map value is the defining instruction. 96 RegMap vregsDeadIn; 97 98 // Regs killed in MBB. They may be defined again, and will then be in both 99 // regsKilled and regsLiveOut. 100 RegSet regsKilled; 101 102 // Regs defined in MBB and live out. Note that vregs passing through may 103 // be live out without being mentioned here. 104 RegSet regsLiveOut; 105 106 // Vregs that pass through MBB untouched. This set is disjoint from 107 // regsKilled and regsLiveOut. 108 RegSet vregsPassed; 109 110 // Vregs that must pass through MBB because they are needed by a successor 111 // block. This set is disjoint from regsLiveOut. 112 RegSet vregsRequired; 113 114 BBInfo() : reachable(false) {} 115 116 // Add register to vregsPassed if it belongs there. Return true if 117 // anything changed. 118 bool addPassed(unsigned Reg) { 119 if (!TargetRegisterInfo::isVirtualRegister(Reg)) 120 return false; 121 if (regsKilled.count(Reg) || regsLiveOut.count(Reg)) 122 return false; 123 return vregsPassed.insert(Reg).second; 124 } 125 126 // Same for a full set. 127 bool addPassed(const RegSet &RS) { 128 bool changed = false; 129 for (RegSet::const_iterator I = RS.begin(), E = RS.end(); I != E; ++I) 130 if (addPassed(*I)) 131 changed = true; 132 return changed; 133 } 134 135 // Add register to vregsRequired if it belongs there. Return true if 136 // anything changed. 137 bool addRequired(unsigned Reg) { 138 if (!TargetRegisterInfo::isVirtualRegister(Reg)) 139 return false; 140 if (regsLiveOut.count(Reg)) 141 return false; 142 return vregsRequired.insert(Reg).second; 143 } 144 145 // Same for a full set. 146 bool addRequired(const RegSet &RS) { 147 bool changed = false; 148 for (RegSet::const_iterator I = RS.begin(), E = RS.end(); I != E; ++I) 149 if (addRequired(*I)) 150 changed = true; 151 return changed; 152 } 153 154 // Same for a full map. 155 bool addRequired(const RegMap &RM) { 156 bool changed = false; 157 for (RegMap::const_iterator I = RM.begin(), E = RM.end(); I != E; ++I) 158 if (addRequired(I->first)) 159 changed = true; 160 return changed; 161 } 162 163 // Live-out registers are either in regsLiveOut or vregsPassed. 164 bool isLiveOut(unsigned Reg) const { 165 return regsLiveOut.count(Reg) || vregsPassed.count(Reg); 166 } 167 }; 168 169 // Extra register info per MBB. 170 DenseMap<const MachineBasicBlock*, BBInfo> MBBInfoMap; 171 172 bool isReserved(unsigned Reg) { 173 return Reg < regsReserved.size() && regsReserved.test(Reg); 174 } 175 176 // Analysis information if available 177 LiveVariables *LiveVars; 178 179 void visitMachineFunctionBefore(); 180 void visitMachineBasicBlockBefore(const MachineBasicBlock *MBB); 181 void visitMachineInstrBefore(const MachineInstr *MI); 182 void visitMachineOperand(const MachineOperand *MO, unsigned MONum); 183 void visitMachineInstrAfter(const MachineInstr *MI); 184 void visitMachineBasicBlockAfter(const MachineBasicBlock *MBB); 185 void visitMachineFunctionAfter(); 186 187 void report(const char *msg, const MachineFunction *MF); 188 void report(const char *msg, const MachineBasicBlock *MBB); 189 void report(const char *msg, const MachineInstr *MI); 190 void report(const char *msg, const MachineOperand *MO, unsigned MONum); 191 192 void markReachable(const MachineBasicBlock *MBB); 193 void calcRegsPassed(); 194 void checkPHIOps(const MachineBasicBlock *MBB); 195 196 void calcRegsRequired(); 197 void verifyLiveVariables(); 198 }; 199 200 struct MachineVerifierPass : public MachineFunctionPass { 201 static char ID; // Pass ID, replacement for typeid 202 bool AllowDoubleDefs; 203 204 explicit MachineVerifierPass(bool allowDoubleDefs = false) 205 : MachineFunctionPass(&ID), 206 AllowDoubleDefs(allowDoubleDefs) {} 207 208 void getAnalysisUsage(AnalysisUsage &AU) const { 209 AU.setPreservesAll(); 210 MachineFunctionPass::getAnalysisUsage(AU); 211 } 212 213 bool runOnMachineFunction(MachineFunction &MF) { 214 MF.verify(this, AllowDoubleDefs); 215 return false; 216 } 217 }; 218 219} 220 221char MachineVerifierPass::ID = 0; 222static RegisterPass<MachineVerifierPass> 223MachineVer("machineverifier", "Verify generated machine code"); 224static const PassInfo *const MachineVerifyID = &MachineVer; 225 226FunctionPass *llvm::createMachineVerifierPass(bool allowPhysDoubleDefs) { 227 return new MachineVerifierPass(allowPhysDoubleDefs); 228} 229 230void MachineFunction::verify(Pass *p, bool allowDoubleDefs) const { 231 MachineVerifier(p, allowDoubleDefs) 232 .runOnMachineFunction(const_cast<MachineFunction&>(*this)); 233} 234 235bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) { 236 raw_ostream *OutFile = 0; 237 if (OutFileName) { 238 std::string ErrorInfo; 239 OutFile = new raw_fd_ostream(OutFileName, ErrorInfo, 240 raw_fd_ostream::F_Append); 241 if (!ErrorInfo.empty()) { 242 errs() << "Error opening '" << OutFileName << "': " << ErrorInfo << '\n'; 243 exit(1); 244 } 245 246 OS = OutFile; 247 } else { 248 OS = &errs(); 249 } 250 251 foundErrors = 0; 252 253 this->MF = &MF; 254 TM = &MF.getTarget(); 255 TRI = TM->getRegisterInfo(); 256 MRI = &MF.getRegInfo(); 257 258 if (PASS) { 259 LiveVars = PASS->getAnalysisIfAvailable<LiveVariables>(); 260 } else { 261 LiveVars = NULL; 262 } 263 264 visitMachineFunctionBefore(); 265 for (MachineFunction::const_iterator MFI = MF.begin(), MFE = MF.end(); 266 MFI!=MFE; ++MFI) { 267 visitMachineBasicBlockBefore(MFI); 268 for (MachineBasicBlock::const_iterator MBBI = MFI->begin(), 269 MBBE = MFI->end(); MBBI != MBBE; ++MBBI) { 270 visitMachineInstrBefore(MBBI); 271 for (unsigned I = 0, E = MBBI->getNumOperands(); I != E; ++I) 272 visitMachineOperand(&MBBI->getOperand(I), I); 273 visitMachineInstrAfter(MBBI); 274 } 275 visitMachineBasicBlockAfter(MFI); 276 } 277 visitMachineFunctionAfter(); 278 279 if (OutFile) 280 delete OutFile; 281 else if (foundErrors) 282 report_fatal_error("Found "+Twine(foundErrors)+" machine code errors."); 283 284 // Clean up. 285 regsLive.clear(); 286 regsDefined.clear(); 287 regsDead.clear(); 288 regsKilled.clear(); 289 regsLiveInButUnused.clear(); 290 MBBInfoMap.clear(); 291 292 return false; // no changes 293} 294 295void MachineVerifier::report(const char *msg, const MachineFunction *MF) { 296 assert(MF); 297 *OS << '\n'; 298 if (!foundErrors++) 299 MF->print(*OS); 300 *OS << "*** Bad machine code: " << msg << " ***\n" 301 << "- function: " << MF->getFunction()->getNameStr() << "\n"; 302} 303 304void MachineVerifier::report(const char *msg, const MachineBasicBlock *MBB) { 305 assert(MBB); 306 report(msg, MBB->getParent()); 307 *OS << "- basic block: " << MBB->getName() 308 << " " << (void*)MBB 309 << " (BB#" << MBB->getNumber() << ")\n"; 310} 311 312void MachineVerifier::report(const char *msg, const MachineInstr *MI) { 313 assert(MI); 314 report(msg, MI->getParent()); 315 *OS << "- instruction: "; 316 MI->print(*OS, TM); 317} 318 319void MachineVerifier::report(const char *msg, 320 const MachineOperand *MO, unsigned MONum) { 321 assert(MO); 322 report(msg, MO->getParent()); 323 *OS << "- operand " << MONum << ": "; 324 MO->print(*OS, TM); 325 *OS << "\n"; 326} 327 328void MachineVerifier::markReachable(const MachineBasicBlock *MBB) { 329 BBInfo &MInfo = MBBInfoMap[MBB]; 330 if (!MInfo.reachable) { 331 MInfo.reachable = true; 332 for (MachineBasicBlock::const_succ_iterator SuI = MBB->succ_begin(), 333 SuE = MBB->succ_end(); SuI != SuE; ++SuI) 334 markReachable(*SuI); 335 } 336} 337 338void MachineVerifier::visitMachineFunctionBefore() { 339 regsReserved = TRI->getReservedRegs(*MF); 340 341 // A sub-register of a reserved register is also reserved 342 for (int Reg = regsReserved.find_first(); Reg>=0; 343 Reg = regsReserved.find_next(Reg)) { 344 for (const unsigned *Sub = TRI->getSubRegisters(Reg); *Sub; ++Sub) { 345 // FIXME: This should probably be: 346 // assert(regsReserved.test(*Sub) && "Non-reserved sub-register"); 347 regsReserved.set(*Sub); 348 } 349 } 350 markReachable(&MF->front()); 351} 352 353// Does iterator point to a and b as the first two elements? 354static bool matchPair(MachineBasicBlock::const_succ_iterator i, 355 const MachineBasicBlock *a, const MachineBasicBlock *b) { 356 if (*i == a) 357 return *++i == b; 358 if (*i == b) 359 return *++i == a; 360 return false; 361} 362 363void 364MachineVerifier::visitMachineBasicBlockBefore(const MachineBasicBlock *MBB) { 365 const TargetInstrInfo *TII = MF->getTarget().getInstrInfo(); 366 367 // Call AnalyzeBranch. If it succeeds, there several more conditions to check. 368 MachineBasicBlock *TBB = 0, *FBB = 0; 369 SmallVector<MachineOperand, 4> Cond; 370 if (!TII->AnalyzeBranch(*const_cast<MachineBasicBlock *>(MBB), 371 TBB, FBB, Cond)) { 372 // Ok, AnalyzeBranch thinks it knows what's going on with this block. Let's 373 // check whether its answers match up with reality. 374 if (!TBB && !FBB) { 375 // Block falls through to its successor. 376 MachineFunction::const_iterator MBBI = MBB; 377 ++MBBI; 378 if (MBBI == MF->end()) { 379 // It's possible that the block legitimately ends with a noreturn 380 // call or an unreachable, in which case it won't actually fall 381 // out the bottom of the function. 382 } else if (MBB->succ_empty()) { 383 // It's possible that the block legitimately ends with a noreturn 384 // call or an unreachable, in which case it won't actuall fall 385 // out of the block. 386 } else if (MBB->succ_size() != 1) { 387 report("MBB exits via unconditional fall-through but doesn't have " 388 "exactly one CFG successor!", MBB); 389 } else if (MBB->succ_begin()[0] != MBBI) { 390 report("MBB exits via unconditional fall-through but its successor " 391 "differs from its CFG successor!", MBB); 392 } 393 if (!MBB->empty() && MBB->back().getDesc().isBarrier()) { 394 report("MBB exits via unconditional fall-through but ends with a " 395 "barrier instruction!", MBB); 396 } 397 if (!Cond.empty()) { 398 report("MBB exits via unconditional fall-through but has a condition!", 399 MBB); 400 } 401 } else if (TBB && !FBB && Cond.empty()) { 402 // Block unconditionally branches somewhere. 403 if (MBB->succ_size() != 1) { 404 report("MBB exits via unconditional branch but doesn't have " 405 "exactly one CFG successor!", MBB); 406 } else if (MBB->succ_begin()[0] != TBB) { 407 report("MBB exits via unconditional branch but the CFG " 408 "successor doesn't match the actual successor!", MBB); 409 } 410 if (MBB->empty()) { 411 report("MBB exits via unconditional branch but doesn't contain " 412 "any instructions!", MBB); 413 } else if (!MBB->back().getDesc().isBarrier()) { 414 report("MBB exits via unconditional branch but doesn't end with a " 415 "barrier instruction!", MBB); 416 } else if (!MBB->back().getDesc().isTerminator()) { 417 report("MBB exits via unconditional branch but the branch isn't a " 418 "terminator instruction!", MBB); 419 } 420 } else if (TBB && !FBB && !Cond.empty()) { 421 // Block conditionally branches somewhere, otherwise falls through. 422 MachineFunction::const_iterator MBBI = MBB; 423 ++MBBI; 424 if (MBBI == MF->end()) { 425 report("MBB conditionally falls through out of function!", MBB); 426 } if (MBB->succ_size() != 2) { 427 report("MBB exits via conditional branch/fall-through but doesn't have " 428 "exactly two CFG successors!", MBB); 429 } else if (!matchPair(MBB->succ_begin(), TBB, MBBI)) { 430 report("MBB exits via conditional branch/fall-through but the CFG " 431 "successors don't match the actual successors!", MBB); 432 } 433 if (MBB->empty()) { 434 report("MBB exits via conditional branch/fall-through but doesn't " 435 "contain any instructions!", MBB); 436 } else if (MBB->back().getDesc().isBarrier()) { 437 report("MBB exits via conditional branch/fall-through but ends with a " 438 "barrier instruction!", MBB); 439 } else if (!MBB->back().getDesc().isTerminator()) { 440 report("MBB exits via conditional branch/fall-through but the branch " 441 "isn't a terminator instruction!", MBB); 442 } 443 } else if (TBB && FBB) { 444 // Block conditionally branches somewhere, otherwise branches 445 // somewhere else. 446 if (MBB->succ_size() != 2) { 447 report("MBB exits via conditional branch/branch but doesn't have " 448 "exactly two CFG successors!", MBB); 449 } else if (!matchPair(MBB->succ_begin(), TBB, FBB)) { 450 report("MBB exits via conditional branch/branch but the CFG " 451 "successors don't match the actual successors!", MBB); 452 } 453 if (MBB->empty()) { 454 report("MBB exits via conditional branch/branch but doesn't " 455 "contain any instructions!", MBB); 456 } else if (!MBB->back().getDesc().isBarrier()) { 457 report("MBB exits via conditional branch/branch but doesn't end with a " 458 "barrier instruction!", MBB); 459 } else if (!MBB->back().getDesc().isTerminator()) { 460 report("MBB exits via conditional branch/branch but the branch " 461 "isn't a terminator instruction!", MBB); 462 } 463 if (Cond.empty()) { 464 report("MBB exits via conditinal branch/branch but there's no " 465 "condition!", MBB); 466 } 467 } else { 468 report("AnalyzeBranch returned invalid data!", MBB); 469 } 470 } 471 472 regsLive.clear(); 473 for (MachineBasicBlock::livein_iterator I = MBB->livein_begin(), 474 E = MBB->livein_end(); I != E; ++I) { 475 if (!TargetRegisterInfo::isPhysicalRegister(*I)) { 476 report("MBB live-in list contains non-physical register", MBB); 477 continue; 478 } 479 regsLive.insert(*I); 480 for (const unsigned *R = TRI->getSubRegisters(*I); *R; R++) 481 regsLive.insert(*R); 482 } 483 regsLiveInButUnused = regsLive; 484 485 const MachineFrameInfo *MFI = MF->getFrameInfo(); 486 assert(MFI && "Function has no frame info"); 487 BitVector PR = MFI->getPristineRegs(MBB); 488 for (int I = PR.find_first(); I>0; I = PR.find_next(I)) { 489 regsLive.insert(I); 490 for (const unsigned *R = TRI->getSubRegisters(I); *R; R++) 491 regsLive.insert(*R); 492 } 493 494 regsKilled.clear(); 495 regsDefined.clear(); 496} 497 498void MachineVerifier::visitMachineInstrBefore(const MachineInstr *MI) { 499 const TargetInstrDesc &TI = MI->getDesc(); 500 if (MI->getNumOperands() < TI.getNumOperands()) { 501 report("Too few operands", MI); 502 *OS << TI.getNumOperands() << " operands expected, but " 503 << MI->getNumExplicitOperands() << " given.\n"; 504 } 505 506 // Check the MachineMemOperands for basic consistency. 507 for (MachineInstr::mmo_iterator I = MI->memoperands_begin(), 508 E = MI->memoperands_end(); I != E; ++I) { 509 if ((*I)->isLoad() && !TI.mayLoad()) 510 report("Missing mayLoad flag", MI); 511 if ((*I)->isStore() && !TI.mayStore()) 512 report("Missing mayStore flag", MI); 513 } 514} 515 516void 517MachineVerifier::visitMachineOperand(const MachineOperand *MO, unsigned MONum) { 518 const MachineInstr *MI = MO->getParent(); 519 const TargetInstrDesc &TI = MI->getDesc(); 520 521 // The first TI.NumDefs operands must be explicit register defines 522 if (MONum < TI.getNumDefs()) { 523 if (!MO->isReg()) 524 report("Explicit definition must be a register", MO, MONum); 525 else if (!MO->isDef()) 526 report("Explicit definition marked as use", MO, MONum); 527 else if (MO->isImplicit()) 528 report("Explicit definition marked as implicit", MO, MONum); 529 } else if (MONum < TI.getNumOperands()) { 530 if (MO->isReg()) { 531 if (MO->isDef()) 532 report("Explicit operand marked as def", MO, MONum); 533 if (MO->isImplicit()) 534 report("Explicit operand marked as implicit", MO, MONum); 535 } 536 } else { 537 // ARM adds %reg0 operands to indicate predicates. We'll allow that. 538 if (MO->isReg() && !MO->isImplicit() && !TI.isVariadic() && MO->getReg()) 539 report("Extra explicit operand on non-variadic instruction", MO, MONum); 540 } 541 542 switch (MO->getType()) { 543 case MachineOperand::MO_Register: { 544 const unsigned Reg = MO->getReg(); 545 if (!Reg) 546 return; 547 548 // Check Live Variables. 549 if (MO->isUndef()) { 550 // An <undef> doesn't refer to any register, so just skip it. 551 } else if (MO->isUse()) { 552 regsLiveInButUnused.erase(Reg); 553 554 bool isKill = false; 555 unsigned defIdx; 556 if (MI->isRegTiedToDefOperand(MONum, &defIdx)) { 557 // A two-addr use counts as a kill if use and def are the same. 558 unsigned DefReg = MI->getOperand(defIdx).getReg(); 559 if (Reg == DefReg) { 560 isKill = true; 561 // ANd in that case an explicit kill flag is not allowed. 562 if (MO->isKill()) 563 report("Illegal kill flag on two-address instruction operand", 564 MO, MONum); 565 } else if (TargetRegisterInfo::isPhysicalRegister(Reg)) { 566 report("Two-address instruction operands must be identical", 567 MO, MONum); 568 } 569 } else 570 isKill = MO->isKill(); 571 572 if (isKill) { 573 addRegWithSubRegs(regsKilled, Reg); 574 575 // Check that LiveVars knows this kill 576 if (LiveVars && TargetRegisterInfo::isVirtualRegister(Reg)) { 577 LiveVariables::VarInfo &VI = LiveVars->getVarInfo(Reg); 578 if (std::find(VI.Kills.begin(), 579 VI.Kills.end(), MI) == VI.Kills.end()) 580 report("Kill missing from LiveVariables", MO, MONum); 581 } 582 } 583 584 // Use of a dead register. 585 if (!regsLive.count(Reg)) { 586 if (TargetRegisterInfo::isPhysicalRegister(Reg)) { 587 // Reserved registers may be used even when 'dead'. 588 if (!isReserved(Reg)) 589 report("Using an undefined physical register", MO, MONum); 590 } else { 591 BBInfo &MInfo = MBBInfoMap[MI->getParent()]; 592 // We don't know which virtual registers are live in, so only complain 593 // if vreg was killed in this MBB. Otherwise keep track of vregs that 594 // must be live in. PHI instructions are handled separately. 595 if (MInfo.regsKilled.count(Reg)) 596 report("Using a killed virtual register", MO, MONum); 597 else if (!MI->isPHI()) 598 MInfo.vregsLiveIn.insert(std::make_pair(Reg, MI)); 599 } 600 } 601 } else { 602 assert(MO->isDef()); 603 // Register defined. 604 // TODO: verify that earlyclobber ops are not used. 605 if (MO->isDead()) 606 addRegWithSubRegs(regsDead, Reg); 607 else 608 addRegWithSubRegs(regsDefined, Reg); 609 } 610 611 // Check register classes. 612 if (MONum < TI.getNumOperands() && !MO->isImplicit()) { 613 const TargetOperandInfo &TOI = TI.OpInfo[MONum]; 614 unsigned SubIdx = MO->getSubReg(); 615 616 if (TargetRegisterInfo::isPhysicalRegister(Reg)) { 617 unsigned sr = Reg; 618 if (SubIdx) { 619 unsigned s = TRI->getSubReg(Reg, SubIdx); 620 if (!s) { 621 report("Invalid subregister index for physical register", 622 MO, MONum); 623 return; 624 } 625 sr = s; 626 } 627 if (const TargetRegisterClass *DRC = TOI.getRegClass(TRI)) { 628 if (!DRC->contains(sr)) { 629 report("Illegal physical register for instruction", MO, MONum); 630 *OS << TRI->getName(sr) << " is not a " 631 << DRC->getName() << " register.\n"; 632 } 633 } 634 } else { 635 // Virtual register. 636 const TargetRegisterClass *RC = MRI->getRegClass(Reg); 637 if (SubIdx) { 638 const TargetRegisterClass *SRC = RC->getSubRegisterRegClass(SubIdx); 639 if (!SRC) { 640 report("Invalid subregister index for virtual register", MO, MONum); 641 *OS << "Register class " << RC->getName() 642 << " does not support subreg index " << SubIdx << "\n"; 643 return; 644 } 645 RC = SRC; 646 } 647 if (const TargetRegisterClass *DRC = TOI.getRegClass(TRI)) { 648 if (RC != DRC && !RC->hasSuperClass(DRC)) { 649 report("Illegal virtual register for instruction", MO, MONum); 650 *OS << "Expected a " << DRC->getName() << " register, but got a " 651 << RC->getName() << " register\n"; 652 } 653 } 654 } 655 } 656 break; 657 } 658 659 case MachineOperand::MO_MachineBasicBlock: 660 if (MI->isPHI() && !MO->getMBB()->isSuccessor(MI->getParent())) 661 report("PHI operand is not in the CFG", MO, MONum); 662 break; 663 664 default: 665 break; 666 } 667} 668 669void MachineVerifier::visitMachineInstrAfter(const MachineInstr *MI) { 670 BBInfo &MInfo = MBBInfoMap[MI->getParent()]; 671 set_union(MInfo.regsKilled, regsKilled); 672 set_subtract(regsLive, regsKilled); 673 regsKilled.clear(); 674 675 // Verify that both <def> and <def,dead> operands refer to dead registers. 676 RegVector defs(regsDefined); 677 defs.append(regsDead.begin(), regsDead.end()); 678 679 for (RegVector::const_iterator I = defs.begin(), E = defs.end(); 680 I != E; ++I) { 681 if (regsLive.count(*I)) { 682 if (TargetRegisterInfo::isPhysicalRegister(*I)) { 683 if (!allowPhysDoubleDefs && !isReserved(*I) && 684 !regsLiveInButUnused.count(*I)) { 685 report("Redefining a live physical register", MI); 686 *OS << "Register " << TRI->getName(*I) 687 << " was defined but already live.\n"; 688 } 689 } else { 690 if (!allowVirtDoubleDefs) { 691 report("Redefining a live virtual register", MI); 692 *OS << "Virtual register %reg" << *I 693 << " was defined but already live.\n"; 694 } 695 } 696 } else if (TargetRegisterInfo::isVirtualRegister(*I) && 697 !MInfo.regsKilled.count(*I)) { 698 // Virtual register defined without being killed first must be dead on 699 // entry. 700 MInfo.vregsDeadIn.insert(std::make_pair(*I, MI)); 701 } 702 } 703 704 set_subtract(regsLive, regsDead); regsDead.clear(); 705 set_union(regsLive, regsDefined); regsDefined.clear(); 706} 707 708void 709MachineVerifier::visitMachineBasicBlockAfter(const MachineBasicBlock *MBB) { 710 MBBInfoMap[MBB].regsLiveOut = regsLive; 711 regsLive.clear(); 712} 713 714// Calculate the largest possible vregsPassed sets. These are the registers that 715// can pass through an MBB live, but may not be live every time. It is assumed 716// that all vregsPassed sets are empty before the call. 717void MachineVerifier::calcRegsPassed() { 718 // First push live-out regs to successors' vregsPassed. Remember the MBBs that 719 // have any vregsPassed. 720 DenseSet<const MachineBasicBlock*> todo; 721 for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); 722 MFI != MFE; ++MFI) { 723 const MachineBasicBlock &MBB(*MFI); 724 BBInfo &MInfo = MBBInfoMap[&MBB]; 725 if (!MInfo.reachable) 726 continue; 727 for (MachineBasicBlock::const_succ_iterator SuI = MBB.succ_begin(), 728 SuE = MBB.succ_end(); SuI != SuE; ++SuI) { 729 BBInfo &SInfo = MBBInfoMap[*SuI]; 730 if (SInfo.addPassed(MInfo.regsLiveOut)) 731 todo.insert(*SuI); 732 } 733 } 734 735 // Iteratively push vregsPassed to successors. This will converge to the same 736 // final state regardless of DenseSet iteration order. 737 while (!todo.empty()) { 738 const MachineBasicBlock *MBB = *todo.begin(); 739 todo.erase(MBB); 740 BBInfo &MInfo = MBBInfoMap[MBB]; 741 for (MachineBasicBlock::const_succ_iterator SuI = MBB->succ_begin(), 742 SuE = MBB->succ_end(); SuI != SuE; ++SuI) { 743 if (*SuI == MBB) 744 continue; 745 BBInfo &SInfo = MBBInfoMap[*SuI]; 746 if (SInfo.addPassed(MInfo.vregsPassed)) 747 todo.insert(*SuI); 748 } 749 } 750} 751 752// Calculate the set of virtual registers that must be passed through each basic 753// block in order to satisfy the requirements of successor blocks. This is very 754// similar to calcRegsPassed, only backwards. 755void MachineVerifier::calcRegsRequired() { 756 // First push live-in regs to predecessors' vregsRequired. 757 DenseSet<const MachineBasicBlock*> todo; 758 for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); 759 MFI != MFE; ++MFI) { 760 const MachineBasicBlock &MBB(*MFI); 761 BBInfo &MInfo = MBBInfoMap[&MBB]; 762 for (MachineBasicBlock::const_pred_iterator PrI = MBB.pred_begin(), 763 PrE = MBB.pred_end(); PrI != PrE; ++PrI) { 764 BBInfo &PInfo = MBBInfoMap[*PrI]; 765 if (PInfo.addRequired(MInfo.vregsLiveIn)) 766 todo.insert(*PrI); 767 } 768 } 769 770 // Iteratively push vregsRequired to predecessors. This will converge to the 771 // same final state regardless of DenseSet iteration order. 772 while (!todo.empty()) { 773 const MachineBasicBlock *MBB = *todo.begin(); 774 todo.erase(MBB); 775 BBInfo &MInfo = MBBInfoMap[MBB]; 776 for (MachineBasicBlock::const_pred_iterator PrI = MBB->pred_begin(), 777 PrE = MBB->pred_end(); PrI != PrE; ++PrI) { 778 if (*PrI == MBB) 779 continue; 780 BBInfo &SInfo = MBBInfoMap[*PrI]; 781 if (SInfo.addRequired(MInfo.vregsRequired)) 782 todo.insert(*PrI); 783 } 784 } 785} 786 787// Check PHI instructions at the beginning of MBB. It is assumed that 788// calcRegsPassed has been run so BBInfo::isLiveOut is valid. 789void MachineVerifier::checkPHIOps(const MachineBasicBlock *MBB) { 790 for (MachineBasicBlock::const_iterator BBI = MBB->begin(), BBE = MBB->end(); 791 BBI != BBE && BBI->isPHI(); ++BBI) { 792 DenseSet<const MachineBasicBlock*> seen; 793 794 for (unsigned i = 1, e = BBI->getNumOperands(); i != e; i += 2) { 795 unsigned Reg = BBI->getOperand(i).getReg(); 796 const MachineBasicBlock *Pre = BBI->getOperand(i + 1).getMBB(); 797 if (!Pre->isSuccessor(MBB)) 798 continue; 799 seen.insert(Pre); 800 BBInfo &PrInfo = MBBInfoMap[Pre]; 801 if (PrInfo.reachable && !PrInfo.isLiveOut(Reg)) 802 report("PHI operand is not live-out from predecessor", 803 &BBI->getOperand(i), i); 804 } 805 806 // Did we see all predecessors? 807 for (MachineBasicBlock::const_pred_iterator PrI = MBB->pred_begin(), 808 PrE = MBB->pred_end(); PrI != PrE; ++PrI) { 809 if (!seen.count(*PrI)) { 810 report("Missing PHI operand", BBI); 811 *OS << "BB#" << (*PrI)->getNumber() 812 << " is a predecessor according to the CFG.\n"; 813 } 814 } 815 } 816} 817 818void MachineVerifier::visitMachineFunctionAfter() { 819 calcRegsPassed(); 820 821 for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); 822 MFI != MFE; ++MFI) { 823 BBInfo &MInfo = MBBInfoMap[MFI]; 824 825 // Skip unreachable MBBs. 826 if (!MInfo.reachable) 827 continue; 828 829 checkPHIOps(MFI); 830 831 // Verify dead-in virtual registers. 832 if (!allowVirtDoubleDefs) { 833 for (MachineBasicBlock::const_pred_iterator PrI = MFI->pred_begin(), 834 PrE = MFI->pred_end(); PrI != PrE; ++PrI) { 835 BBInfo &PrInfo = MBBInfoMap[*PrI]; 836 if (!PrInfo.reachable) 837 continue; 838 839 for (RegMap::iterator I = MInfo.vregsDeadIn.begin(), 840 E = MInfo.vregsDeadIn.end(); I != E; ++I) { 841 // DeadIn register must be in neither regsLiveOut or vregsPassed of 842 // any predecessor. 843 if (PrInfo.isLiveOut(I->first)) { 844 report("Live-in virtual register redefined", I->second); 845 *OS << "Register %reg" << I->first 846 << " was live-out from predecessor MBB #" 847 << (*PrI)->getNumber() << ".\n"; 848 } 849 } 850 } 851 } 852 } 853 854 // Now check LiveVariables info if available 855 if (LiveVars) { 856 calcRegsRequired(); 857 verifyLiveVariables(); 858 } 859} 860 861void MachineVerifier::verifyLiveVariables() { 862 assert(LiveVars && "Don't call verifyLiveVariables without LiveVars"); 863 for (unsigned Reg = TargetRegisterInfo::FirstVirtualRegister, 864 RegE = MRI->getLastVirtReg()-1; Reg != RegE; ++Reg) { 865 LiveVariables::VarInfo &VI = LiveVars->getVarInfo(Reg); 866 for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end(); 867 MFI != MFE; ++MFI) { 868 BBInfo &MInfo = MBBInfoMap[MFI]; 869 870 // Our vregsRequired should be identical to LiveVariables' AliveBlocks 871 if (MInfo.vregsRequired.count(Reg)) { 872 if (!VI.AliveBlocks.test(MFI->getNumber())) { 873 report("LiveVariables: Block missing from AliveBlocks", MFI); 874 *OS << "Virtual register %reg" << Reg 875 << " must be live through the block.\n"; 876 } 877 } else { 878 if (VI.AliveBlocks.test(MFI->getNumber())) { 879 report("LiveVariables: Block should not be in AliveBlocks", MFI); 880 *OS << "Virtual register %reg" << Reg 881 << " is not needed live through the block.\n"; 882 } 883 } 884 } 885 } 886} 887 888 889