1 //===- bolt/Core/BinaryFunction.cpp - Low-level function ------------------===// 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 implements the BinaryFunction class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "bolt/Core/BinaryFunction.h" 14 #include "bolt/Core/BinaryBasicBlock.h" 15 #include "bolt/Core/DynoStats.h" 16 #include "bolt/Core/HashUtilities.h" 17 #include "bolt/Core/MCPlusBuilder.h" 18 #include "bolt/Utils/NameResolver.h" 19 #include "bolt/Utils/NameShortener.h" 20 #include "bolt/Utils/Utils.h" 21 #include "llvm/ADT/STLExtras.h" 22 #include "llvm/ADT/SmallSet.h" 23 #include "llvm/ADT/StringExtras.h" 24 #include "llvm/ADT/StringRef.h" 25 #include "llvm/Demangle/Demangle.h" 26 #include "llvm/MC/MCAsmInfo.h" 27 #include "llvm/MC/MCContext.h" 28 #include "llvm/MC/MCDisassembler/MCDisassembler.h" 29 #include "llvm/MC/MCExpr.h" 30 #include "llvm/MC/MCInst.h" 31 #include "llvm/MC/MCInstPrinter.h" 32 #include "llvm/MC/MCRegisterInfo.h" 33 #include "llvm/MC/MCSymbol.h" 34 #include "llvm/Object/ObjectFile.h" 35 #include "llvm/Support/CommandLine.h" 36 #include "llvm/Support/Debug.h" 37 #include "llvm/Support/GenericDomTreeConstruction.h" 38 #include "llvm/Support/GenericLoopInfoImpl.h" 39 #include "llvm/Support/GraphWriter.h" 40 #include "llvm/Support/LEB128.h" 41 #include "llvm/Support/Regex.h" 42 #include "llvm/Support/Timer.h" 43 #include "llvm/Support/raw_ostream.h" 44 #include "llvm/Support/xxhash.h" 45 #include <functional> 46 #include <limits> 47 #include <numeric> 48 #include <stack> 49 #include <string> 50 51 #define DEBUG_TYPE "bolt" 52 53 using namespace llvm; 54 using namespace bolt; 55 56 namespace opts { 57 58 extern cl::OptionCategory BoltCategory; 59 extern cl::OptionCategory BoltOptCategory; 60 61 extern cl::opt<bool> EnableBAT; 62 extern cl::opt<bool> Instrument; 63 extern cl::opt<bool> StrictMode; 64 extern cl::opt<bool> UpdateDebugSections; 65 extern cl::opt<unsigned> Verbosity; 66 67 extern bool processAllFunctions(); 68 69 cl::opt<bool> CheckEncoding( 70 "check-encoding", 71 cl::desc("perform verification of LLVM instruction encoding/decoding. " 72 "Every instruction in the input is decoded and re-encoded. " 73 "If the resulting bytes do not match the input, a warning message " 74 "is printed."), 75 cl::Hidden, cl::cat(BoltCategory)); 76 77 static cl::opt<bool> DotToolTipCode( 78 "dot-tooltip-code", 79 cl::desc("add basic block instructions as tool tips on nodes"), cl::Hidden, 80 cl::cat(BoltCategory)); 81 82 cl::opt<JumpTableSupportLevel> 83 JumpTables("jump-tables", 84 cl::desc("jump tables support (default=basic)"), 85 cl::init(JTS_BASIC), 86 cl::values( 87 clEnumValN(JTS_NONE, "none", 88 "do not optimize functions with jump tables"), 89 clEnumValN(JTS_BASIC, "basic", 90 "optimize functions with jump tables"), 91 clEnumValN(JTS_MOVE, "move", 92 "move jump tables to a separate section"), 93 clEnumValN(JTS_SPLIT, "split", 94 "split jump tables section into hot and cold based on " 95 "function execution frequency"), 96 clEnumValN(JTS_AGGRESSIVE, "aggressive", 97 "aggressively split jump tables section based on usage " 98 "of the tables")), 99 cl::ZeroOrMore, 100 cl::cat(BoltOptCategory)); 101 102 static cl::opt<bool> NoScan( 103 "no-scan", 104 cl::desc( 105 "do not scan cold functions for external references (may result in " 106 "slower binary)"), 107 cl::Hidden, cl::cat(BoltOptCategory)); 108 109 cl::opt<bool> 110 PreserveBlocksAlignment("preserve-blocks-alignment", 111 cl::desc("try to preserve basic block alignment"), 112 cl::cat(BoltOptCategory)); 113 114 static cl::opt<bool> PrintOutputAddressRange( 115 "print-output-address-range", 116 cl::desc( 117 "print output address range for each basic block in the function when" 118 "BinaryFunction::print is called"), 119 cl::Hidden, cl::cat(BoltOptCategory)); 120 121 cl::opt<bool> 122 PrintDynoStats("dyno-stats", 123 cl::desc("print execution info based on profile"), 124 cl::cat(BoltCategory)); 125 126 static cl::opt<bool> 127 PrintDynoStatsOnly("print-dyno-stats-only", 128 cl::desc("while printing functions output dyno-stats and skip instructions"), 129 cl::init(false), 130 cl::Hidden, 131 cl::cat(BoltCategory)); 132 133 static cl::list<std::string> 134 PrintOnly("print-only", 135 cl::CommaSeparated, 136 cl::desc("list of functions to print"), 137 cl::value_desc("func1,func2,func3,..."), 138 cl::Hidden, 139 cl::cat(BoltCategory)); 140 141 cl::opt<bool> 142 TimeBuild("time-build", 143 cl::desc("print time spent constructing binary functions"), 144 cl::Hidden, cl::cat(BoltCategory)); 145 146 cl::opt<bool> 147 TrapOnAVX512("trap-avx512", 148 cl::desc("in relocation mode trap upon entry to any function that uses " 149 "AVX-512 instructions"), 150 cl::init(false), 151 cl::ZeroOrMore, 152 cl::Hidden, 153 cl::cat(BoltCategory)); 154 155 bool shouldPrint(const BinaryFunction &Function) { 156 if (Function.isIgnored()) 157 return false; 158 159 if (PrintOnly.empty()) 160 return true; 161 162 for (std::string &Name : opts::PrintOnly) { 163 if (Function.hasNameRegex(Name)) { 164 return true; 165 } 166 } 167 168 std::optional<StringRef> Origin = Function.getOriginSectionName(); 169 if (Origin && llvm::any_of(opts::PrintOnly, [&](const std::string &Name) { 170 return Name == *Origin; 171 })) 172 return true; 173 174 return false; 175 } 176 177 } // namespace opts 178 179 namespace llvm { 180 namespace bolt { 181 182 template <typename R> static bool emptyRange(const R &Range) { 183 return Range.begin() == Range.end(); 184 } 185 186 /// Gets debug line information for the instruction located at the given 187 /// address in the original binary. The SMLoc's pointer is used 188 /// to point to this information, which is represented by a 189 /// DebugLineTableRowRef. The returned pointer is null if no debug line 190 /// information for this instruction was found. 191 static SMLoc findDebugLineInformationForInstructionAt( 192 uint64_t Address, DWARFUnit *Unit, 193 const DWARFDebugLine::LineTable *LineTable) { 194 // We use the pointer in SMLoc to store an instance of DebugLineTableRowRef, 195 // which occupies 64 bits. Thus, we can only proceed if the struct fits into 196 // the pointer itself. 197 static_assert( 198 sizeof(decltype(SMLoc().getPointer())) >= sizeof(DebugLineTableRowRef), 199 "Cannot fit instruction debug line information into SMLoc's pointer"); 200 201 SMLoc NullResult = DebugLineTableRowRef::NULL_ROW.toSMLoc(); 202 uint32_t RowIndex = LineTable->lookupAddress( 203 {Address, object::SectionedAddress::UndefSection}); 204 if (RowIndex == LineTable->UnknownRowIndex) 205 return NullResult; 206 207 assert(RowIndex < LineTable->Rows.size() && 208 "Line Table lookup returned invalid index."); 209 210 decltype(SMLoc().getPointer()) Ptr; 211 DebugLineTableRowRef *InstructionLocation = 212 reinterpret_cast<DebugLineTableRowRef *>(&Ptr); 213 214 InstructionLocation->DwCompileUnitIndex = Unit->getOffset(); 215 InstructionLocation->RowIndex = RowIndex + 1; 216 217 return SMLoc::getFromPointer(Ptr); 218 } 219 220 static std::string buildSectionName(StringRef Prefix, StringRef Name, 221 const BinaryContext &BC) { 222 if (BC.isELF()) 223 return (Prefix + Name).str(); 224 static NameShortener NS; 225 return (Prefix + Twine(NS.getID(Name))).str(); 226 } 227 228 static raw_ostream &operator<<(raw_ostream &OS, 229 const BinaryFunction::State State) { 230 switch (State) { 231 case BinaryFunction::State::Empty: OS << "empty"; break; 232 case BinaryFunction::State::Disassembled: OS << "disassembled"; break; 233 case BinaryFunction::State::CFG: OS << "CFG constructed"; break; 234 case BinaryFunction::State::CFG_Finalized: OS << "CFG finalized"; break; 235 case BinaryFunction::State::EmittedCFG: OS << "emitted with CFG"; break; 236 case BinaryFunction::State::Emitted: OS << "emitted"; break; 237 } 238 239 return OS; 240 } 241 242 std::string BinaryFunction::buildCodeSectionName(StringRef Name, 243 const BinaryContext &BC) { 244 return buildSectionName(BC.isELF() ? ".local.text." : ".l.text.", Name, BC); 245 } 246 247 std::string BinaryFunction::buildColdCodeSectionName(StringRef Name, 248 const BinaryContext &BC) { 249 return buildSectionName(BC.isELF() ? ".local.cold.text." : ".l.c.text.", Name, 250 BC); 251 } 252 253 uint64_t BinaryFunction::Count = 0; 254 255 std::optional<StringRef> 256 BinaryFunction::hasNameRegex(const StringRef Name) const { 257 const std::string RegexName = (Twine("^") + StringRef(Name) + "$").str(); 258 Regex MatchName(RegexName); 259 return forEachName( 260 [&MatchName](StringRef Name) { return MatchName.match(Name); }); 261 } 262 263 std::optional<StringRef> 264 BinaryFunction::hasRestoredNameRegex(const StringRef Name) const { 265 const std::string RegexName = (Twine("^") + StringRef(Name) + "$").str(); 266 Regex MatchName(RegexName); 267 return forEachName([&MatchName](StringRef Name) { 268 return MatchName.match(NameResolver::restore(Name)); 269 }); 270 } 271 272 std::string BinaryFunction::getDemangledName() const { 273 StringRef MangledName = NameResolver::restore(getOneName()); 274 return demangle(MangledName.str()); 275 } 276 277 BinaryBasicBlock * 278 BinaryFunction::getBasicBlockContainingOffset(uint64_t Offset) { 279 if (Offset > Size) 280 return nullptr; 281 282 if (BasicBlockOffsets.empty()) 283 return nullptr; 284 285 /* 286 * This is commented out because it makes BOLT too slow. 287 * assert(std::is_sorted(BasicBlockOffsets.begin(), 288 * BasicBlockOffsets.end(), 289 * CompareBasicBlockOffsets()))); 290 */ 291 auto I = 292 llvm::upper_bound(BasicBlockOffsets, BasicBlockOffset(Offset, nullptr), 293 CompareBasicBlockOffsets()); 294 assert(I != BasicBlockOffsets.begin() && "first basic block not at offset 0"); 295 --I; 296 BinaryBasicBlock *BB = I->second; 297 return (Offset < BB->getOffset() + BB->getOriginalSize()) ? BB : nullptr; 298 } 299 300 void BinaryFunction::markUnreachableBlocks() { 301 std::stack<BinaryBasicBlock *> Stack; 302 303 for (BinaryBasicBlock &BB : blocks()) 304 BB.markValid(false); 305 306 // Add all entries and landing pads as roots. 307 for (BinaryBasicBlock *BB : BasicBlocks) { 308 if (isEntryPoint(*BB) || BB->isLandingPad()) { 309 Stack.push(BB); 310 BB->markValid(true); 311 continue; 312 } 313 // FIXME: 314 // Also mark BBs with indirect jumps as reachable, since we do not 315 // support removing unused jump tables yet (GH-issue20). 316 for (const MCInst &Inst : *BB) { 317 if (BC.MIB->getJumpTable(Inst)) { 318 Stack.push(BB); 319 BB->markValid(true); 320 break; 321 } 322 } 323 } 324 325 // Determine reachable BBs from the entry point 326 while (!Stack.empty()) { 327 BinaryBasicBlock *BB = Stack.top(); 328 Stack.pop(); 329 for (BinaryBasicBlock *Succ : BB->successors()) { 330 if (Succ->isValid()) 331 continue; 332 Succ->markValid(true); 333 Stack.push(Succ); 334 } 335 } 336 } 337 338 // Any unnecessary fallthrough jumps revealed after calling eraseInvalidBBs 339 // will be cleaned up by fixBranches(). 340 std::pair<unsigned, uint64_t> 341 BinaryFunction::eraseInvalidBBs(const MCCodeEmitter *Emitter) { 342 DenseSet<const BinaryBasicBlock *> InvalidBBs; 343 unsigned Count = 0; 344 uint64_t Bytes = 0; 345 for (BinaryBasicBlock *const BB : BasicBlocks) { 346 if (!BB->isValid()) { 347 assert(!isEntryPoint(*BB) && "all entry blocks must be valid"); 348 InvalidBBs.insert(BB); 349 ++Count; 350 Bytes += BC.computeCodeSize(BB->begin(), BB->end(), Emitter); 351 } 352 } 353 354 Layout.eraseBasicBlocks(InvalidBBs); 355 356 BasicBlockListType NewBasicBlocks; 357 for (auto I = BasicBlocks.begin(), E = BasicBlocks.end(); I != E; ++I) { 358 BinaryBasicBlock *BB = *I; 359 if (InvalidBBs.contains(BB)) { 360 // Make sure the block is removed from the list of predecessors. 361 BB->removeAllSuccessors(); 362 DeletedBasicBlocks.push_back(BB); 363 } else { 364 NewBasicBlocks.push_back(BB); 365 } 366 } 367 BasicBlocks = std::move(NewBasicBlocks); 368 369 assert(BasicBlocks.size() == Layout.block_size()); 370 371 // Update CFG state if needed 372 if (Count > 0) 373 recomputeLandingPads(); 374 375 return std::make_pair(Count, Bytes); 376 } 377 378 bool BinaryFunction::isForwardCall(const MCSymbol *CalleeSymbol) const { 379 // This function should work properly before and after function reordering. 380 // In order to accomplish this, we use the function index (if it is valid). 381 // If the function indices are not valid, we fall back to the original 382 // addresses. This should be ok because the functions without valid indices 383 // should have been ordered with a stable sort. 384 const BinaryFunction *CalleeBF = BC.getFunctionForSymbol(CalleeSymbol); 385 if (CalleeBF) { 386 if (CalleeBF->isInjected()) 387 return true; 388 return compareBinaryFunctionByIndex(this, CalleeBF); 389 } else { 390 // Absolute symbol. 391 ErrorOr<uint64_t> CalleeAddressOrError = BC.getSymbolValue(*CalleeSymbol); 392 assert(CalleeAddressOrError && "unregistered symbol found"); 393 return *CalleeAddressOrError > getAddress(); 394 } 395 } 396 397 void BinaryFunction::dump() const { 398 // getDynoStats calls FunctionLayout::updateLayoutIndices and 399 // BasicBlock::analyzeBranch. The former cannot be const, but should be 400 // removed, the latter should be made const, but seems to require refactoring. 401 // Forcing all callers to have a non-const reference to BinaryFunction to call 402 // dump non-const however is not ideal either. Adding this const_cast is right 403 // now the best solution. It is safe, because BinaryFunction itself is not 404 // modified. Only BinaryBasicBlocks are actually modified (if it all) and we 405 // have mutable pointers to those regardless whether this function is 406 // const-qualified or not. 407 const_cast<BinaryFunction &>(*this).print(dbgs(), ""); 408 } 409 410 void BinaryFunction::print(raw_ostream &OS, std::string Annotation) { 411 if (!opts::shouldPrint(*this)) 412 return; 413 414 StringRef SectionName = 415 OriginSection ? OriginSection->getName() : "<no origin section>"; 416 OS << "Binary Function \"" << *this << "\" " << Annotation << " {"; 417 std::vector<StringRef> AllNames = getNames(); 418 if (AllNames.size() > 1) { 419 OS << "\n All names : "; 420 const char *Sep = ""; 421 for (const StringRef &Name : AllNames) { 422 OS << Sep << Name; 423 Sep = "\n "; 424 } 425 } 426 OS << "\n Number : " << FunctionNumber; 427 OS << "\n State : " << CurrentState; 428 OS << "\n Address : 0x" << Twine::utohexstr(Address); 429 OS << "\n Size : 0x" << Twine::utohexstr(Size); 430 OS << "\n MaxSize : 0x" << Twine::utohexstr(MaxSize); 431 OS << "\n Offset : 0x" << Twine::utohexstr(getFileOffset()); 432 OS << "\n Section : " << SectionName; 433 OS << "\n Orc Section : " << getCodeSectionName(); 434 OS << "\n LSDA : 0x" << Twine::utohexstr(getLSDAAddress()); 435 OS << "\n IsSimple : " << IsSimple; 436 OS << "\n IsMultiEntry: " << isMultiEntry(); 437 OS << "\n IsSplit : " << isSplit(); 438 OS << "\n BB Count : " << size(); 439 440 if (HasUnknownControlFlow) 441 OS << "\n Unknown CF : true"; 442 if (getPersonalityFunction()) 443 OS << "\n Personality : " << getPersonalityFunction()->getName(); 444 if (IsFragment) 445 OS << "\n IsFragment : true"; 446 if (isFolded()) 447 OS << "\n FoldedInto : " << *getFoldedIntoFunction(); 448 for (BinaryFunction *ParentFragment : ParentFragments) 449 OS << "\n Parent : " << *ParentFragment; 450 if (!Fragments.empty()) { 451 OS << "\n Fragments : "; 452 ListSeparator LS; 453 for (BinaryFunction *Frag : Fragments) 454 OS << LS << *Frag; 455 } 456 if (hasCFG()) 457 OS << "\n Hash : " << Twine::utohexstr(computeHash()); 458 if (isMultiEntry()) { 459 OS << "\n Secondary Entry Points : "; 460 ListSeparator LS; 461 for (const auto &KV : SecondaryEntryPoints) 462 OS << LS << KV.second->getName(); 463 } 464 if (FrameInstructions.size()) 465 OS << "\n CFI Instrs : " << FrameInstructions.size(); 466 if (!Layout.block_empty()) { 467 OS << "\n BB Layout : "; 468 ListSeparator LS; 469 for (const BinaryBasicBlock *BB : Layout.blocks()) 470 OS << LS << BB->getName(); 471 } 472 if (getImageAddress()) 473 OS << "\n Image : 0x" << Twine::utohexstr(getImageAddress()); 474 if (ExecutionCount != COUNT_NO_PROFILE) { 475 OS << "\n Exec Count : " << ExecutionCount; 476 OS << "\n Branch Count: " << RawBranchCount; 477 OS << "\n Profile Acc : " << format("%.1f%%", ProfileMatchRatio * 100.0f); 478 } 479 480 if (opts::PrintDynoStats && !getLayout().block_empty()) { 481 OS << '\n'; 482 DynoStats dynoStats = getDynoStats(*this); 483 OS << dynoStats; 484 } 485 486 OS << "\n}\n"; 487 488 if (opts::PrintDynoStatsOnly || !BC.InstPrinter) 489 return; 490 491 // Offset of the instruction in function. 492 uint64_t Offset = 0; 493 494 if (BasicBlocks.empty() && !Instructions.empty()) { 495 // Print before CFG was built. 496 for (const std::pair<const uint32_t, MCInst> &II : Instructions) { 497 Offset = II.first; 498 499 // Print label if exists at this offset. 500 auto LI = Labels.find(Offset); 501 if (LI != Labels.end()) { 502 if (const MCSymbol *EntrySymbol = 503 getSecondaryEntryPointSymbol(LI->second)) 504 OS << EntrySymbol->getName() << " (Entry Point):\n"; 505 OS << LI->second->getName() << ":\n"; 506 } 507 508 BC.printInstruction(OS, II.second, Offset, this); 509 } 510 } 511 512 StringRef SplitPointMsg = ""; 513 for (const FunctionFragment &FF : Layout.fragments()) { 514 OS << SplitPointMsg; 515 SplitPointMsg = "------- HOT-COLD SPLIT POINT -------\n\n"; 516 for (const BinaryBasicBlock *BB : FF) { 517 OS << BB->getName() << " (" << BB->size() 518 << " instructions, align : " << BB->getAlignment() << ")\n"; 519 520 if (opts::PrintOutputAddressRange) 521 OS << formatv(" Output Address Range: [{0:x}, {1:x}) ({2} bytes)\n", 522 BB->getOutputAddressRange().first, 523 BB->getOutputAddressRange().second, BB->getOutputSize()); 524 525 if (isEntryPoint(*BB)) { 526 if (MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(*BB)) 527 OS << " Secondary Entry Point: " << EntrySymbol->getName() << '\n'; 528 else 529 OS << " Entry Point\n"; 530 } 531 532 if (BB->isLandingPad()) 533 OS << " Landing Pad\n"; 534 535 uint64_t BBExecCount = BB->getExecutionCount(); 536 if (hasValidProfile()) { 537 OS << " Exec Count : "; 538 if (BB->getExecutionCount() != BinaryBasicBlock::COUNT_NO_PROFILE) 539 OS << BBExecCount << '\n'; 540 else 541 OS << "<unknown>\n"; 542 } 543 if (hasCFI()) 544 OS << " CFI State : " << BB->getCFIState() << '\n'; 545 if (opts::EnableBAT) { 546 OS << " Input offset: 0x" << Twine::utohexstr(BB->getInputOffset()) 547 << "\n"; 548 } 549 if (!BB->pred_empty()) { 550 OS << " Predecessors: "; 551 ListSeparator LS; 552 for (BinaryBasicBlock *Pred : BB->predecessors()) 553 OS << LS << Pred->getName(); 554 OS << '\n'; 555 } 556 if (!BB->throw_empty()) { 557 OS << " Throwers: "; 558 ListSeparator LS; 559 for (BinaryBasicBlock *Throw : BB->throwers()) 560 OS << LS << Throw->getName(); 561 OS << '\n'; 562 } 563 564 Offset = alignTo(Offset, BB->getAlignment()); 565 566 // Note: offsets are imprecise since this is happening prior to 567 // relaxation. 568 Offset = BC.printInstructions(OS, BB->begin(), BB->end(), Offset, this); 569 570 if (!BB->succ_empty()) { 571 OS << " Successors: "; 572 // For more than 2 successors, sort them based on frequency. 573 std::vector<uint64_t> Indices(BB->succ_size()); 574 std::iota(Indices.begin(), Indices.end(), 0); 575 if (BB->succ_size() > 2 && BB->getKnownExecutionCount()) { 576 llvm::stable_sort(Indices, [&](const uint64_t A, const uint64_t B) { 577 return BB->BranchInfo[B] < BB->BranchInfo[A]; 578 }); 579 } 580 ListSeparator LS; 581 for (unsigned I = 0; I < Indices.size(); ++I) { 582 BinaryBasicBlock *Succ = BB->Successors[Indices[I]]; 583 const BinaryBasicBlock::BinaryBranchInfo &BI = 584 BB->BranchInfo[Indices[I]]; 585 OS << LS << Succ->getName(); 586 if (ExecutionCount != COUNT_NO_PROFILE && 587 BI.MispredictedCount != BinaryBasicBlock::COUNT_INFERRED) { 588 OS << " (mispreds: " << BI.MispredictedCount 589 << ", count: " << BI.Count << ")"; 590 } else if (ExecutionCount != COUNT_NO_PROFILE && 591 BI.Count != BinaryBasicBlock::COUNT_NO_PROFILE) { 592 OS << " (inferred count: " << BI.Count << ")"; 593 } 594 } 595 OS << '\n'; 596 } 597 598 if (!BB->lp_empty()) { 599 OS << " Landing Pads: "; 600 ListSeparator LS; 601 for (BinaryBasicBlock *LP : BB->landing_pads()) { 602 OS << LS << LP->getName(); 603 if (ExecutionCount != COUNT_NO_PROFILE) { 604 OS << " (count: " << LP->getExecutionCount() << ")"; 605 } 606 } 607 OS << '\n'; 608 } 609 610 // In CFG_Finalized state we can miscalculate CFI state at exit. 611 if (CurrentState == State::CFG && hasCFI()) { 612 const int32_t CFIStateAtExit = BB->getCFIStateAtExit(); 613 if (CFIStateAtExit >= 0) 614 OS << " CFI State: " << CFIStateAtExit << '\n'; 615 } 616 617 OS << '\n'; 618 } 619 } 620 621 // Dump new exception ranges for the function. 622 if (!CallSites.empty()) { 623 OS << "EH table:\n"; 624 for (const FunctionFragment &FF : getLayout().fragments()) { 625 for (const auto &FCSI : getCallSites(FF.getFragmentNum())) { 626 const CallSite &CSI = FCSI.second; 627 OS << " [" << *CSI.Start << ", " << *CSI.End << ") landing pad : "; 628 if (CSI.LP) 629 OS << *CSI.LP; 630 else 631 OS << "0"; 632 OS << ", action : " << CSI.Action << '\n'; 633 } 634 } 635 OS << '\n'; 636 } 637 638 // Print all jump tables. 639 for (const std::pair<const uint64_t, JumpTable *> &JTI : JumpTables) 640 JTI.second->print(OS); 641 642 OS << "DWARF CFI Instructions:\n"; 643 if (OffsetToCFI.size()) { 644 // Pre-buildCFG information 645 for (const std::pair<const uint32_t, uint32_t> &Elmt : OffsetToCFI) { 646 OS << format(" %08x:\t", Elmt.first); 647 assert(Elmt.second < FrameInstructions.size() && "Incorrect CFI offset"); 648 BinaryContext::printCFI(OS, FrameInstructions[Elmt.second]); 649 OS << "\n"; 650 } 651 } else { 652 // Post-buildCFG information 653 for (uint32_t I = 0, E = FrameInstructions.size(); I != E; ++I) { 654 const MCCFIInstruction &CFI = FrameInstructions[I]; 655 OS << format(" %d:\t", I); 656 BinaryContext::printCFI(OS, CFI); 657 OS << "\n"; 658 } 659 } 660 if (FrameInstructions.empty()) 661 OS << " <empty>\n"; 662 663 OS << "End of Function \"" << *this << "\"\n\n"; 664 } 665 666 void BinaryFunction::printRelocations(raw_ostream &OS, uint64_t Offset, 667 uint64_t Size) const { 668 const char *Sep = " # Relocs: "; 669 670 auto RI = Relocations.lower_bound(Offset); 671 while (RI != Relocations.end() && RI->first < Offset + Size) { 672 OS << Sep << "(R: " << RI->second << ")"; 673 Sep = ", "; 674 ++RI; 675 } 676 } 677 678 static std::string mutateDWARFExpressionTargetReg(const MCCFIInstruction &Instr, 679 MCPhysReg NewReg) { 680 StringRef ExprBytes = Instr.getValues(); 681 assert(ExprBytes.size() > 1 && "DWARF expression CFI is too short"); 682 uint8_t Opcode = ExprBytes[0]; 683 assert((Opcode == dwarf::DW_CFA_expression || 684 Opcode == dwarf::DW_CFA_val_expression) && 685 "invalid DWARF expression CFI"); 686 (void)Opcode; 687 const uint8_t *const Start = 688 reinterpret_cast<const uint8_t *>(ExprBytes.drop_front(1).data()); 689 const uint8_t *const End = 690 reinterpret_cast<const uint8_t *>(Start + ExprBytes.size() - 1); 691 unsigned Size = 0; 692 decodeULEB128(Start, &Size, End); 693 assert(Size > 0 && "Invalid reg encoding for DWARF expression CFI"); 694 SmallString<8> Tmp; 695 raw_svector_ostream OSE(Tmp); 696 encodeULEB128(NewReg, OSE); 697 return Twine(ExprBytes.slice(0, 1)) 698 .concat(OSE.str()) 699 .concat(ExprBytes.drop_front(1 + Size)) 700 .str(); 701 } 702 703 void BinaryFunction::mutateCFIRegisterFor(const MCInst &Instr, 704 MCPhysReg NewReg) { 705 const MCCFIInstruction *OldCFI = getCFIFor(Instr); 706 assert(OldCFI && "invalid CFI instr"); 707 switch (OldCFI->getOperation()) { 708 default: 709 llvm_unreachable("Unexpected instruction"); 710 case MCCFIInstruction::OpDefCfa: 711 setCFIFor(Instr, MCCFIInstruction::cfiDefCfa(nullptr, NewReg, 712 OldCFI->getOffset())); 713 break; 714 case MCCFIInstruction::OpDefCfaRegister: 715 setCFIFor(Instr, MCCFIInstruction::createDefCfaRegister(nullptr, NewReg)); 716 break; 717 case MCCFIInstruction::OpOffset: 718 setCFIFor(Instr, MCCFIInstruction::createOffset(nullptr, NewReg, 719 OldCFI->getOffset())); 720 break; 721 case MCCFIInstruction::OpRegister: 722 setCFIFor(Instr, MCCFIInstruction::createRegister(nullptr, NewReg, 723 OldCFI->getRegister2())); 724 break; 725 case MCCFIInstruction::OpSameValue: 726 setCFIFor(Instr, MCCFIInstruction::createSameValue(nullptr, NewReg)); 727 break; 728 case MCCFIInstruction::OpEscape: 729 setCFIFor(Instr, 730 MCCFIInstruction::createEscape( 731 nullptr, 732 StringRef(mutateDWARFExpressionTargetReg(*OldCFI, NewReg)))); 733 break; 734 case MCCFIInstruction::OpRestore: 735 setCFIFor(Instr, MCCFIInstruction::createRestore(nullptr, NewReg)); 736 break; 737 case MCCFIInstruction::OpUndefined: 738 setCFIFor(Instr, MCCFIInstruction::createUndefined(nullptr, NewReg)); 739 break; 740 } 741 } 742 743 const MCCFIInstruction *BinaryFunction::mutateCFIOffsetFor(const MCInst &Instr, 744 int64_t NewOffset) { 745 const MCCFIInstruction *OldCFI = getCFIFor(Instr); 746 assert(OldCFI && "invalid CFI instr"); 747 switch (OldCFI->getOperation()) { 748 default: 749 llvm_unreachable("Unexpected instruction"); 750 case MCCFIInstruction::OpDefCfaOffset: 751 setCFIFor(Instr, MCCFIInstruction::cfiDefCfaOffset(nullptr, NewOffset)); 752 break; 753 case MCCFIInstruction::OpAdjustCfaOffset: 754 setCFIFor(Instr, 755 MCCFIInstruction::createAdjustCfaOffset(nullptr, NewOffset)); 756 break; 757 case MCCFIInstruction::OpDefCfa: 758 setCFIFor(Instr, MCCFIInstruction::cfiDefCfa(nullptr, OldCFI->getRegister(), 759 NewOffset)); 760 break; 761 case MCCFIInstruction::OpOffset: 762 setCFIFor(Instr, MCCFIInstruction::createOffset( 763 nullptr, OldCFI->getRegister(), NewOffset)); 764 break; 765 } 766 return getCFIFor(Instr); 767 } 768 769 IndirectBranchType 770 BinaryFunction::processIndirectBranch(MCInst &Instruction, unsigned Size, 771 uint64_t Offset, 772 uint64_t &TargetAddress) { 773 const unsigned PtrSize = BC.AsmInfo->getCodePointerSize(); 774 775 // The instruction referencing memory used by the branch instruction. 776 // It could be the branch instruction itself or one of the instructions 777 // setting the value of the register used by the branch. 778 MCInst *MemLocInstr; 779 780 // The instruction loading the fixed PIC jump table entry value. 781 MCInst *FixedEntryLoadInstr; 782 783 // Address of the table referenced by MemLocInstr. Could be either an 784 // array of function pointers, or a jump table. 785 uint64_t ArrayStart = 0; 786 787 unsigned BaseRegNum, IndexRegNum; 788 int64_t DispValue; 789 const MCExpr *DispExpr; 790 791 // In AArch, identify the instruction adding the PC-relative offset to 792 // jump table entries to correctly decode it. 793 MCInst *PCRelBaseInstr; 794 uint64_t PCRelAddr = 0; 795 796 auto Begin = Instructions.begin(); 797 if (BC.isAArch64()) { 798 PreserveNops = BC.HasRelocations; 799 // Start at the last label as an approximation of the current basic block. 800 // This is a heuristic, since the full set of labels have yet to be 801 // determined 802 for (const uint32_t Offset : 803 llvm::make_first_range(llvm::reverse(Labels))) { 804 auto II = Instructions.find(Offset); 805 if (II != Instructions.end()) { 806 Begin = II; 807 break; 808 } 809 } 810 } 811 812 IndirectBranchType BranchType = BC.MIB->analyzeIndirectBranch( 813 Instruction, Begin, Instructions.end(), PtrSize, MemLocInstr, BaseRegNum, 814 IndexRegNum, DispValue, DispExpr, PCRelBaseInstr, FixedEntryLoadInstr); 815 816 if (BranchType == IndirectBranchType::UNKNOWN && !MemLocInstr) 817 return BranchType; 818 819 if (MemLocInstr != &Instruction) 820 IndexRegNum = BC.MIB->getNoRegister(); 821 822 if (BC.isAArch64()) { 823 const MCSymbol *Sym = BC.MIB->getTargetSymbol(*PCRelBaseInstr, 1); 824 assert(Sym && "Symbol extraction failed"); 825 ErrorOr<uint64_t> SymValueOrError = BC.getSymbolValue(*Sym); 826 if (SymValueOrError) { 827 PCRelAddr = *SymValueOrError; 828 } else { 829 for (std::pair<const uint32_t, MCSymbol *> &Elmt : Labels) { 830 if (Elmt.second == Sym) { 831 PCRelAddr = Elmt.first + getAddress(); 832 break; 833 } 834 } 835 } 836 uint64_t InstrAddr = 0; 837 for (auto II = Instructions.rbegin(); II != Instructions.rend(); ++II) { 838 if (&II->second == PCRelBaseInstr) { 839 InstrAddr = II->first + getAddress(); 840 break; 841 } 842 } 843 assert(InstrAddr != 0 && "instruction not found"); 844 // We do this to avoid spurious references to code locations outside this 845 // function (for example, if the indirect jump lives in the last basic 846 // block of the function, it will create a reference to the next function). 847 // This replaces a symbol reference with an immediate. 848 BC.MIB->replaceMemOperandDisp(*PCRelBaseInstr, 849 MCOperand::createImm(PCRelAddr - InstrAddr)); 850 // FIXME: Disable full jump table processing for AArch64 until we have a 851 // proper way of determining the jump table limits. 852 return IndirectBranchType::UNKNOWN; 853 } 854 855 auto getExprValue = [&](const MCExpr *Expr) { 856 const MCSymbol *TargetSym; 857 uint64_t TargetOffset; 858 std::tie(TargetSym, TargetOffset) = BC.MIB->getTargetSymbolInfo(Expr); 859 ErrorOr<uint64_t> SymValueOrError = BC.getSymbolValue(*TargetSym); 860 assert(SymValueOrError && "Global symbol needs a value"); 861 return *SymValueOrError + TargetOffset; 862 }; 863 864 // RIP-relative addressing should be converted to symbol form by now 865 // in processed instructions (but not in jump). 866 if (DispExpr) { 867 ArrayStart = getExprValue(DispExpr); 868 BaseRegNum = BC.MIB->getNoRegister(); 869 if (BC.isAArch64()) { 870 ArrayStart &= ~0xFFFULL; 871 ArrayStart += DispValue & 0xFFFULL; 872 } 873 } else { 874 ArrayStart = static_cast<uint64_t>(DispValue); 875 } 876 877 if (BaseRegNum == BC.MRI->getProgramCounter()) 878 ArrayStart += getAddress() + Offset + Size; 879 880 if (FixedEntryLoadInstr) { 881 assert(BranchType == IndirectBranchType::POSSIBLE_PIC_FIXED_BRANCH && 882 "Invalid IndirectBranch type"); 883 MCInst::iterator FixedEntryDispOperand = 884 BC.MIB->getMemOperandDisp(*FixedEntryLoadInstr); 885 assert(FixedEntryDispOperand != FixedEntryLoadInstr->end() && 886 "Invalid memory instruction"); 887 const MCExpr *FixedEntryDispExpr = FixedEntryDispOperand->getExpr(); 888 const uint64_t EntryAddress = getExprValue(FixedEntryDispExpr); 889 uint64_t EntrySize = BC.getJumpTableEntrySize(JumpTable::JTT_PIC); 890 ErrorOr<int64_t> Value = 891 BC.getSignedValueAtAddress(EntryAddress, EntrySize); 892 if (!Value) 893 return IndirectBranchType::UNKNOWN; 894 895 BC.outs() << "BOLT-INFO: fixed PIC indirect branch detected in " << *this 896 << " at 0x" << Twine::utohexstr(getAddress() + Offset) 897 << " referencing data at 0x" << Twine::utohexstr(EntryAddress) 898 << " the destination value is 0x" 899 << Twine::utohexstr(ArrayStart + *Value) << '\n'; 900 901 TargetAddress = ArrayStart + *Value; 902 903 // Remove spurious JumpTable at EntryAddress caused by PIC reference from 904 // the load instruction. 905 BC.deleteJumpTable(EntryAddress); 906 907 // Replace FixedEntryDispExpr used in target address calculation with outer 908 // jump table reference. 909 JumpTable *JT = BC.getJumpTableContainingAddress(ArrayStart); 910 assert(JT && "Must have a containing jump table for PIC fixed branch"); 911 BC.MIB->replaceMemOperandDisp(*FixedEntryLoadInstr, JT->getFirstLabel(), 912 EntryAddress - ArrayStart, &*BC.Ctx); 913 914 return BranchType; 915 } 916 917 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: addressed memory is 0x" 918 << Twine::utohexstr(ArrayStart) << '\n'); 919 920 ErrorOr<BinarySection &> Section = BC.getSectionForAddress(ArrayStart); 921 if (!Section) { 922 // No section - possibly an absolute address. Since we don't allow 923 // internal function addresses to escape the function scope - we 924 // consider it a tail call. 925 if (opts::Verbosity >= 1) { 926 BC.errs() << "BOLT-WARNING: no section for address 0x" 927 << Twine::utohexstr(ArrayStart) << " referenced from function " 928 << *this << '\n'; 929 } 930 return IndirectBranchType::POSSIBLE_TAIL_CALL; 931 } 932 if (Section->isVirtual()) { 933 // The contents are filled at runtime. 934 return IndirectBranchType::POSSIBLE_TAIL_CALL; 935 } 936 937 if (BranchType == IndirectBranchType::POSSIBLE_FIXED_BRANCH) { 938 ErrorOr<uint64_t> Value = BC.getPointerAtAddress(ArrayStart); 939 if (!Value) 940 return IndirectBranchType::UNKNOWN; 941 942 if (BC.getSectionForAddress(ArrayStart)->isWritable()) 943 return IndirectBranchType::UNKNOWN; 944 945 BC.outs() << "BOLT-INFO: fixed indirect branch detected in " << *this 946 << " at 0x" << Twine::utohexstr(getAddress() + Offset) 947 << " referencing data at 0x" << Twine::utohexstr(ArrayStart) 948 << " the destination value is 0x" << Twine::utohexstr(*Value) 949 << '\n'; 950 951 TargetAddress = *Value; 952 return BranchType; 953 } 954 955 // Check if there's already a jump table registered at this address. 956 MemoryContentsType MemType; 957 if (JumpTable *JT = BC.getJumpTableContainingAddress(ArrayStart)) { 958 switch (JT->Type) { 959 case JumpTable::JTT_NORMAL: 960 MemType = MemoryContentsType::POSSIBLE_JUMP_TABLE; 961 break; 962 case JumpTable::JTT_PIC: 963 MemType = MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE; 964 break; 965 } 966 } else { 967 MemType = BC.analyzeMemoryAt(ArrayStart, *this); 968 } 969 970 // Check that jump table type in instruction pattern matches memory contents. 971 JumpTable::JumpTableType JTType; 972 if (BranchType == IndirectBranchType::POSSIBLE_PIC_JUMP_TABLE) { 973 if (MemType != MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE) 974 return IndirectBranchType::UNKNOWN; 975 JTType = JumpTable::JTT_PIC; 976 } else { 977 if (MemType == MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE) 978 return IndirectBranchType::UNKNOWN; 979 980 if (MemType == MemoryContentsType::UNKNOWN) 981 return IndirectBranchType::POSSIBLE_TAIL_CALL; 982 983 BranchType = IndirectBranchType::POSSIBLE_JUMP_TABLE; 984 JTType = JumpTable::JTT_NORMAL; 985 } 986 987 // Convert the instruction into jump table branch. 988 const MCSymbol *JTLabel = BC.getOrCreateJumpTable(*this, ArrayStart, JTType); 989 BC.MIB->replaceMemOperandDisp(*MemLocInstr, JTLabel, BC.Ctx.get()); 990 BC.MIB->setJumpTable(Instruction, ArrayStart, IndexRegNum); 991 992 JTSites.emplace_back(Offset, ArrayStart); 993 994 return BranchType; 995 } 996 997 MCSymbol *BinaryFunction::getOrCreateLocalLabel(uint64_t Address, 998 bool CreatePastEnd) { 999 const uint64_t Offset = Address - getAddress(); 1000 1001 if ((Offset == getSize()) && CreatePastEnd) 1002 return getFunctionEndLabel(); 1003 1004 auto LI = Labels.find(Offset); 1005 if (LI != Labels.end()) 1006 return LI->second; 1007 1008 // For AArch64, check if this address is part of a constant island. 1009 if (BC.isAArch64()) { 1010 if (MCSymbol *IslandSym = getOrCreateIslandAccess(Address)) 1011 return IslandSym; 1012 } 1013 1014 MCSymbol *Label = BC.Ctx->createNamedTempSymbol(); 1015 Labels[Offset] = Label; 1016 1017 return Label; 1018 } 1019 1020 ErrorOr<ArrayRef<uint8_t>> BinaryFunction::getData() const { 1021 BinarySection &Section = *getOriginSection(); 1022 assert(Section.containsRange(getAddress(), getMaxSize()) && 1023 "wrong section for function"); 1024 1025 if (!Section.isText() || Section.isVirtual() || !Section.getSize()) 1026 return std::make_error_code(std::errc::bad_address); 1027 1028 StringRef SectionContents = Section.getContents(); 1029 1030 assert(SectionContents.size() == Section.getSize() && 1031 "section size mismatch"); 1032 1033 // Function offset from the section start. 1034 uint64_t Offset = getAddress() - Section.getAddress(); 1035 auto *Bytes = reinterpret_cast<const uint8_t *>(SectionContents.data()); 1036 return ArrayRef<uint8_t>(Bytes + Offset, getMaxSize()); 1037 } 1038 1039 size_t BinaryFunction::getSizeOfDataInCodeAt(uint64_t Offset) const { 1040 if (!Islands) 1041 return 0; 1042 1043 if (!llvm::is_contained(Islands->DataOffsets, Offset)) 1044 return 0; 1045 1046 auto Iter = Islands->CodeOffsets.upper_bound(Offset); 1047 if (Iter != Islands->CodeOffsets.end()) 1048 return *Iter - Offset; 1049 return getSize() - Offset; 1050 } 1051 1052 bool BinaryFunction::isZeroPaddingAt(uint64_t Offset) const { 1053 ArrayRef<uint8_t> FunctionData = *getData(); 1054 uint64_t EndOfCode = getSize(); 1055 if (Islands) { 1056 auto Iter = Islands->DataOffsets.upper_bound(Offset); 1057 if (Iter != Islands->DataOffsets.end()) 1058 EndOfCode = *Iter; 1059 } 1060 for (uint64_t I = Offset; I < EndOfCode; ++I) 1061 if (FunctionData[I] != 0) 1062 return false; 1063 1064 return true; 1065 } 1066 1067 Error BinaryFunction::handlePCRelOperand(MCInst &Instruction, uint64_t Address, 1068 uint64_t Size) { 1069 auto &MIB = BC.MIB; 1070 uint64_t TargetAddress = 0; 1071 if (!MIB->evaluateMemOperandTarget(Instruction, TargetAddress, Address, 1072 Size)) { 1073 std::string Msg; 1074 raw_string_ostream SS(Msg); 1075 SS << "BOLT-ERROR: PC-relative operand can't be evaluated:\n"; 1076 BC.InstPrinter->printInst(&Instruction, 0, "", *BC.STI, SS); 1077 SS << '\n'; 1078 Instruction.dump_pretty(SS, BC.InstPrinter.get()); 1079 SS << '\n'; 1080 SS << "BOLT-ERROR: cannot handle PC-relative operand at 0x" 1081 << Twine::utohexstr(Address) << ". Skipping function " << *this << ".\n"; 1082 if (BC.HasRelocations) 1083 return createFatalBOLTError(Msg); 1084 IsSimple = false; 1085 return createNonFatalBOLTError(Msg); 1086 } 1087 if (TargetAddress == 0 && opts::Verbosity >= 1) { 1088 BC.outs() << "BOLT-INFO: PC-relative operand is zero in function " << *this 1089 << '\n'; 1090 } 1091 1092 const MCSymbol *TargetSymbol; 1093 uint64_t TargetOffset; 1094 std::tie(TargetSymbol, TargetOffset) = 1095 BC.handleAddressRef(TargetAddress, *this, /*IsPCRel*/ true); 1096 1097 bool ReplaceSuccess = MIB->replaceMemOperandDisp( 1098 Instruction, TargetSymbol, static_cast<int64_t>(TargetOffset), &*BC.Ctx); 1099 (void)ReplaceSuccess; 1100 assert(ReplaceSuccess && "Failed to replace mem operand with symbol+off."); 1101 return Error::success(); 1102 } 1103 1104 MCSymbol *BinaryFunction::handleExternalReference(MCInst &Instruction, 1105 uint64_t Size, 1106 uint64_t Offset, 1107 uint64_t TargetAddress, 1108 bool &IsCall) { 1109 auto &MIB = BC.MIB; 1110 1111 const uint64_t AbsoluteInstrAddr = getAddress() + Offset; 1112 BC.addInterproceduralReference(this, TargetAddress); 1113 if (opts::Verbosity >= 2 && !IsCall && Size == 2 && !BC.HasRelocations) { 1114 BC.errs() << "BOLT-WARNING: relaxed tail call detected at 0x" 1115 << Twine::utohexstr(AbsoluteInstrAddr) << " in function " << *this 1116 << ". Code size will be increased.\n"; 1117 } 1118 1119 assert(!MIB->isTailCall(Instruction) && 1120 "synthetic tail call instruction found"); 1121 1122 // This is a call regardless of the opcode. 1123 // Assign proper opcode for tail calls, so that they could be 1124 // treated as calls. 1125 if (!IsCall) { 1126 if (!MIB->convertJmpToTailCall(Instruction)) { 1127 assert(MIB->isConditionalBranch(Instruction) && 1128 "unknown tail call instruction"); 1129 if (opts::Verbosity >= 2) { 1130 BC.errs() << "BOLT-WARNING: conditional tail call detected in " 1131 << "function " << *this << " at 0x" 1132 << Twine::utohexstr(AbsoluteInstrAddr) << ".\n"; 1133 } 1134 } 1135 IsCall = true; 1136 } 1137 1138 if (opts::Verbosity >= 2 && TargetAddress == 0) { 1139 // We actually see calls to address 0 in presence of weak 1140 // symbols originating from libraries. This code is never meant 1141 // to be executed. 1142 BC.outs() << "BOLT-INFO: Function " << *this 1143 << " has a call to address zero.\n"; 1144 } 1145 1146 return BC.getOrCreateGlobalSymbol(TargetAddress, "FUNCat"); 1147 } 1148 1149 void BinaryFunction::handleIndirectBranch(MCInst &Instruction, uint64_t Size, 1150 uint64_t Offset) { 1151 auto &MIB = BC.MIB; 1152 uint64_t IndirectTarget = 0; 1153 IndirectBranchType Result = 1154 processIndirectBranch(Instruction, Size, Offset, IndirectTarget); 1155 switch (Result) { 1156 default: 1157 llvm_unreachable("unexpected result"); 1158 case IndirectBranchType::POSSIBLE_TAIL_CALL: { 1159 bool Result = MIB->convertJmpToTailCall(Instruction); 1160 (void)Result; 1161 assert(Result); 1162 break; 1163 } 1164 case IndirectBranchType::POSSIBLE_JUMP_TABLE: 1165 case IndirectBranchType::POSSIBLE_PIC_JUMP_TABLE: 1166 case IndirectBranchType::POSSIBLE_PIC_FIXED_BRANCH: 1167 if (opts::JumpTables == JTS_NONE) 1168 IsSimple = false; 1169 break; 1170 case IndirectBranchType::POSSIBLE_FIXED_BRANCH: { 1171 if (containsAddress(IndirectTarget)) { 1172 const MCSymbol *TargetSymbol = getOrCreateLocalLabel(IndirectTarget); 1173 Instruction.clear(); 1174 MIB->createUncondBranch(Instruction, TargetSymbol, BC.Ctx.get()); 1175 TakenBranches.emplace_back(Offset, IndirectTarget - getAddress()); 1176 addEntryPointAtOffset(IndirectTarget - getAddress()); 1177 } else { 1178 MIB->convertJmpToTailCall(Instruction); 1179 BC.addInterproceduralReference(this, IndirectTarget); 1180 } 1181 break; 1182 } 1183 case IndirectBranchType::UNKNOWN: 1184 // Keep processing. We'll do more checks and fixes in 1185 // postProcessIndirectBranches(). 1186 UnknownIndirectBranchOffsets.emplace(Offset); 1187 break; 1188 } 1189 } 1190 1191 void BinaryFunction::handleAArch64IndirectCall(MCInst &Instruction, 1192 const uint64_t Offset) { 1193 auto &MIB = BC.MIB; 1194 const uint64_t AbsoluteInstrAddr = getAddress() + Offset; 1195 MCInst *TargetHiBits, *TargetLowBits; 1196 uint64_t TargetAddress, Count; 1197 Count = MIB->matchLinkerVeneer(Instructions.begin(), Instructions.end(), 1198 AbsoluteInstrAddr, Instruction, TargetHiBits, 1199 TargetLowBits, TargetAddress); 1200 if (Count) { 1201 MIB->addAnnotation(Instruction, "AArch64Veneer", true); 1202 --Count; 1203 for (auto It = std::prev(Instructions.end()); Count != 0; 1204 It = std::prev(It), --Count) { 1205 MIB->addAnnotation(It->second, "AArch64Veneer", true); 1206 } 1207 1208 BC.addAdrpAddRelocAArch64(*this, *TargetLowBits, *TargetHiBits, 1209 TargetAddress); 1210 } 1211 } 1212 1213 std::optional<MCInst> 1214 BinaryFunction::disassembleInstructionAtOffset(uint64_t Offset) const { 1215 assert(CurrentState == State::Empty && "Function should not be disassembled"); 1216 assert(Offset < MaxSize && "Invalid offset"); 1217 ErrorOr<ArrayRef<unsigned char>> FunctionData = getData(); 1218 assert(FunctionData && "Cannot get function as data"); 1219 MCInst Instr; 1220 uint64_t InstrSize = 0; 1221 const uint64_t InstrAddress = getAddress() + Offset; 1222 if (BC.DisAsm->getInstruction(Instr, InstrSize, FunctionData->slice(Offset), 1223 InstrAddress, nulls())) 1224 return Instr; 1225 return std::nullopt; 1226 } 1227 1228 Error BinaryFunction::disassemble() { 1229 NamedRegionTimer T("disassemble", "Disassemble function", "buildfuncs", 1230 "Build Binary Functions", opts::TimeBuild); 1231 ErrorOr<ArrayRef<uint8_t>> ErrorOrFunctionData = getData(); 1232 assert(ErrorOrFunctionData && "function data is not available"); 1233 ArrayRef<uint8_t> FunctionData = *ErrorOrFunctionData; 1234 assert(FunctionData.size() == getMaxSize() && 1235 "function size does not match raw data size"); 1236 1237 auto &Ctx = BC.Ctx; 1238 auto &MIB = BC.MIB; 1239 1240 BC.SymbolicDisAsm->setSymbolizer(MIB->createTargetSymbolizer(*this)); 1241 1242 // Insert a label at the beginning of the function. This will be our first 1243 // basic block. 1244 Labels[0] = Ctx->createNamedTempSymbol("BB0"); 1245 1246 // Map offsets in the function to a label that should always point to the 1247 // corresponding instruction. This is used for labels that shouldn't point to 1248 // the start of a basic block but always to a specific instruction. This is 1249 // used, for example, on RISC-V where %pcrel_lo relocations point to the 1250 // corresponding %pcrel_hi. 1251 LabelsMapType InstructionLabels; 1252 1253 uint64_t Size = 0; // instruction size 1254 for (uint64_t Offset = 0; Offset < getSize(); Offset += Size) { 1255 MCInst Instruction; 1256 const uint64_t AbsoluteInstrAddr = getAddress() + Offset; 1257 1258 // Check for data inside code and ignore it 1259 if (const size_t DataInCodeSize = getSizeOfDataInCodeAt(Offset)) { 1260 Size = DataInCodeSize; 1261 continue; 1262 } 1263 1264 if (!BC.SymbolicDisAsm->getInstruction(Instruction, Size, 1265 FunctionData.slice(Offset), 1266 AbsoluteInstrAddr, nulls())) { 1267 // Functions with "soft" boundaries, e.g. coming from assembly source, 1268 // can have 0-byte padding at the end. 1269 if (isZeroPaddingAt(Offset)) 1270 break; 1271 1272 BC.errs() 1273 << "BOLT-WARNING: unable to disassemble instruction at offset 0x" 1274 << Twine::utohexstr(Offset) << " (address 0x" 1275 << Twine::utohexstr(AbsoluteInstrAddr) << ") in function " << *this 1276 << '\n'; 1277 // Some AVX-512 instructions could not be disassembled at all. 1278 if (BC.HasRelocations && opts::TrapOnAVX512 && BC.isX86()) { 1279 setTrapOnEntry(); 1280 BC.TrappedFunctions.push_back(this); 1281 } else { 1282 setIgnored(); 1283 } 1284 1285 break; 1286 } 1287 1288 // Check integrity of LLVM assembler/disassembler. 1289 if (opts::CheckEncoding && !BC.MIB->isBranch(Instruction) && 1290 !BC.MIB->isCall(Instruction) && !BC.MIB->isNoop(Instruction)) { 1291 if (!BC.validateInstructionEncoding(FunctionData.slice(Offset, Size))) { 1292 BC.errs() << "BOLT-WARNING: mismatching LLVM encoding detected in " 1293 << "function " << *this << " for instruction :\n"; 1294 BC.printInstruction(BC.errs(), Instruction, AbsoluteInstrAddr); 1295 BC.errs() << '\n'; 1296 } 1297 } 1298 1299 // Special handling for AVX-512 instructions. 1300 if (MIB->hasEVEXEncoding(Instruction)) { 1301 if (BC.HasRelocations && opts::TrapOnAVX512) { 1302 setTrapOnEntry(); 1303 BC.TrappedFunctions.push_back(this); 1304 break; 1305 } 1306 1307 if (!BC.validateInstructionEncoding(FunctionData.slice(Offset, Size))) { 1308 BC.errs() << "BOLT-WARNING: internal assembler/disassembler error " 1309 "detected for AVX512 instruction:\n"; 1310 BC.printInstruction(BC.errs(), Instruction, AbsoluteInstrAddr); 1311 BC.errs() << " in function " << *this << '\n'; 1312 setIgnored(); 1313 break; 1314 } 1315 } 1316 1317 bool IsUnsupported = BC.MIB->isUnsupportedInstruction(Instruction); 1318 if (IsUnsupported) 1319 setIgnored(); 1320 1321 if (MIB->isBranch(Instruction) || MIB->isCall(Instruction)) { 1322 uint64_t TargetAddress = 0; 1323 if (MIB->evaluateBranch(Instruction, AbsoluteInstrAddr, Size, 1324 TargetAddress)) { 1325 // Check if the target is within the same function. Otherwise it's 1326 // a call, possibly a tail call. 1327 // 1328 // If the target *is* the function address it could be either a branch 1329 // or a recursive call. 1330 bool IsCall = MIB->isCall(Instruction); 1331 const bool IsCondBranch = MIB->isConditionalBranch(Instruction); 1332 MCSymbol *TargetSymbol = nullptr; 1333 1334 if (IsUnsupported) 1335 if (auto *TargetFunc = 1336 BC.getBinaryFunctionContainingAddress(TargetAddress)) 1337 TargetFunc->setIgnored(); 1338 1339 if (IsCall && TargetAddress == getAddress()) { 1340 // A recursive call. Calls to internal blocks are handled by 1341 // ValidateInternalCalls pass. 1342 TargetSymbol = getSymbol(); 1343 } 1344 1345 if (!TargetSymbol) { 1346 // Create either local label or external symbol. 1347 if (containsAddress(TargetAddress)) { 1348 TargetSymbol = getOrCreateLocalLabel(TargetAddress); 1349 } else { 1350 if (TargetAddress == getAddress() + getSize() && 1351 TargetAddress < getAddress() + getMaxSize() && 1352 !(BC.isAArch64() && 1353 BC.handleAArch64Veneer(TargetAddress, /*MatchOnly*/ true))) { 1354 // Result of __builtin_unreachable(). 1355 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: jump past end detected at 0x" 1356 << Twine::utohexstr(AbsoluteInstrAddr) 1357 << " in function " << *this 1358 << " : replacing with nop.\n"); 1359 BC.MIB->createNoop(Instruction); 1360 if (IsCondBranch) { 1361 // Register branch offset for profile validation. 1362 IgnoredBranches.emplace_back(Offset, Offset + Size); 1363 } 1364 goto add_instruction; 1365 } 1366 // May update Instruction and IsCall 1367 TargetSymbol = handleExternalReference(Instruction, Size, Offset, 1368 TargetAddress, IsCall); 1369 } 1370 } 1371 1372 if (!IsCall) { 1373 // Add taken branch info. 1374 TakenBranches.emplace_back(Offset, TargetAddress - getAddress()); 1375 } 1376 BC.MIB->replaceBranchTarget(Instruction, TargetSymbol, &*Ctx); 1377 1378 // Mark CTC. 1379 if (IsCondBranch && IsCall) 1380 MIB->setConditionalTailCall(Instruction, TargetAddress); 1381 } else { 1382 // Could not evaluate branch. Should be an indirect call or an 1383 // indirect branch. Bail out on the latter case. 1384 if (MIB->isIndirectBranch(Instruction)) 1385 handleIndirectBranch(Instruction, Size, Offset); 1386 // Indirect call. We only need to fix it if the operand is RIP-relative. 1387 if (IsSimple && MIB->hasPCRelOperand(Instruction)) { 1388 if (auto NewE = handleErrors( 1389 handlePCRelOperand(Instruction, AbsoluteInstrAddr, Size), 1390 [&](const BOLTError &E) -> Error { 1391 if (E.isFatal()) 1392 return Error(std::make_unique<BOLTError>(std::move(E))); 1393 if (!E.getMessage().empty()) 1394 E.log(BC.errs()); 1395 return Error::success(); 1396 })) { 1397 return Error(std::move(NewE)); 1398 } 1399 } 1400 1401 if (BC.isAArch64()) 1402 handleAArch64IndirectCall(Instruction, Offset); 1403 } 1404 } else if (BC.isAArch64() || BC.isRISCV()) { 1405 // Check if there's a relocation associated with this instruction. 1406 bool UsedReloc = false; 1407 for (auto Itr = Relocations.lower_bound(Offset), 1408 ItrE = Relocations.lower_bound(Offset + Size); 1409 Itr != ItrE; ++Itr) { 1410 const Relocation &Relocation = Itr->second; 1411 MCSymbol *Symbol = Relocation.Symbol; 1412 1413 if (Relocation::isInstructionReference(Relocation.Type)) { 1414 uint64_t RefOffset = Relocation.Value - getAddress(); 1415 LabelsMapType::iterator LI = InstructionLabels.find(RefOffset); 1416 1417 if (LI == InstructionLabels.end()) { 1418 Symbol = BC.Ctx->createNamedTempSymbol(); 1419 InstructionLabels.emplace(RefOffset, Symbol); 1420 } else { 1421 Symbol = LI->second; 1422 } 1423 } 1424 1425 int64_t Value = Relocation.Value; 1426 const bool Result = BC.MIB->replaceImmWithSymbolRef( 1427 Instruction, Symbol, Relocation.Addend, Ctx.get(), Value, 1428 Relocation.Type); 1429 (void)Result; 1430 assert(Result && "cannot replace immediate with relocation"); 1431 1432 // For aarch64, if we replaced an immediate with a symbol from a 1433 // relocation, we mark it so we do not try to further process a 1434 // pc-relative operand. All we need is the symbol. 1435 UsedReloc = true; 1436 } 1437 1438 if (!BC.isRISCV() && MIB->hasPCRelOperand(Instruction) && !UsedReloc) { 1439 if (auto NewE = handleErrors( 1440 handlePCRelOperand(Instruction, AbsoluteInstrAddr, Size), 1441 [&](const BOLTError &E) -> Error { 1442 if (E.isFatal()) 1443 return Error(std::make_unique<BOLTError>(std::move(E))); 1444 if (!E.getMessage().empty()) 1445 E.log(BC.errs()); 1446 return Error::success(); 1447 })) 1448 return Error(std::move(NewE)); 1449 } 1450 } 1451 1452 add_instruction: 1453 if (getDWARFLineTable()) { 1454 Instruction.setLoc(findDebugLineInformationForInstructionAt( 1455 AbsoluteInstrAddr, getDWARFUnit(), getDWARFLineTable())); 1456 } 1457 1458 // Record offset of the instruction for profile matching. 1459 if (BC.keepOffsetForInstruction(Instruction)) 1460 MIB->setOffset(Instruction, static_cast<uint32_t>(Offset)); 1461 1462 if (BC.isX86() && BC.MIB->isNoop(Instruction)) { 1463 // NOTE: disassembly loses the correct size information for noops on x86. 1464 // E.g. nopw 0x0(%rax,%rax,1) is 9 bytes, but re-encoded it's only 1465 // 5 bytes. Preserve the size info using annotations. 1466 MIB->setSize(Instruction, Size); 1467 } 1468 1469 addInstruction(Offset, std::move(Instruction)); 1470 } 1471 1472 for (auto [Offset, Label] : InstructionLabels) { 1473 InstrMapType::iterator II = Instructions.find(Offset); 1474 assert(II != Instructions.end() && "reference to non-existing instruction"); 1475 1476 BC.MIB->setInstLabel(II->second, Label); 1477 } 1478 1479 // Reset symbolizer for the disassembler. 1480 BC.SymbolicDisAsm->setSymbolizer(nullptr); 1481 1482 if (uint64_t Offset = getFirstInstructionOffset()) 1483 Labels[Offset] = BC.Ctx->createNamedTempSymbol(); 1484 1485 clearList(Relocations); 1486 1487 if (!IsSimple) { 1488 clearList(Instructions); 1489 return createNonFatalBOLTError(""); 1490 } 1491 1492 updateState(State::Disassembled); 1493 1494 return Error::success(); 1495 } 1496 1497 MCSymbol *BinaryFunction::registerBranch(uint64_t Src, uint64_t Dst) { 1498 assert(CurrentState == State::Disassembled && 1499 "Cannot register branch unless function is in disassembled state."); 1500 assert(containsAddress(Src) && containsAddress(Dst) && 1501 "Cannot register external branch."); 1502 MCSymbol *Target = getOrCreateLocalLabel(Dst); 1503 TakenBranches.emplace_back(Src - getAddress(), Dst - getAddress()); 1504 return Target; 1505 } 1506 1507 void BinaryFunction::analyzeInstructionForFuncReference(const MCInst &Inst) { 1508 for (const MCOperand &Op : MCPlus::primeOperands(Inst)) { 1509 if (!Op.isExpr()) 1510 continue; 1511 const MCExpr &Expr = *Op.getExpr(); 1512 if (Expr.getKind() != MCExpr::SymbolRef) 1513 continue; 1514 const MCSymbol &Symbol = cast<MCSymbolRefExpr>(Expr).getSymbol(); 1515 // Set HasAddressTaken for a function regardless of the ICF level. 1516 if (BinaryFunction *BF = BC.getFunctionForSymbol(&Symbol)) 1517 BF->setHasAddressTaken(true); 1518 } 1519 } 1520 1521 bool BinaryFunction::scanExternalRefs() { 1522 bool Success = true; 1523 bool DisassemblyFailed = false; 1524 1525 // Ignore pseudo functions. 1526 if (isPseudo()) 1527 return Success; 1528 1529 if (opts::NoScan) { 1530 clearList(Relocations); 1531 clearList(ExternallyReferencedOffsets); 1532 1533 return false; 1534 } 1535 1536 // List of external references for this function. 1537 std::vector<Relocation> FunctionRelocations; 1538 1539 static BinaryContext::IndependentCodeEmitter Emitter = 1540 BC.createIndependentMCCodeEmitter(); 1541 1542 ErrorOr<ArrayRef<uint8_t>> ErrorOrFunctionData = getData(); 1543 assert(ErrorOrFunctionData && "function data is not available"); 1544 ArrayRef<uint8_t> FunctionData = *ErrorOrFunctionData; 1545 assert(FunctionData.size() == getMaxSize() && 1546 "function size does not match raw data size"); 1547 1548 BC.SymbolicDisAsm->setSymbolizer( 1549 BC.MIB->createTargetSymbolizer(*this, /*CreateSymbols*/ false)); 1550 1551 // Disassemble contents of the function. Detect code entry points and create 1552 // relocations for references to code that will be moved. 1553 uint64_t Size = 0; // instruction size 1554 for (uint64_t Offset = 0; Offset < getSize(); Offset += Size) { 1555 // Check for data inside code and ignore it 1556 if (const size_t DataInCodeSize = getSizeOfDataInCodeAt(Offset)) { 1557 Size = DataInCodeSize; 1558 continue; 1559 } 1560 1561 const uint64_t AbsoluteInstrAddr = getAddress() + Offset; 1562 MCInst Instruction; 1563 if (!BC.SymbolicDisAsm->getInstruction(Instruction, Size, 1564 FunctionData.slice(Offset), 1565 AbsoluteInstrAddr, nulls())) { 1566 if (opts::Verbosity >= 1 && !isZeroPaddingAt(Offset)) { 1567 BC.errs() 1568 << "BOLT-WARNING: unable to disassemble instruction at offset 0x" 1569 << Twine::utohexstr(Offset) << " (address 0x" 1570 << Twine::utohexstr(AbsoluteInstrAddr) << ") in function " << *this 1571 << '\n'; 1572 } 1573 Success = false; 1574 DisassemblyFailed = true; 1575 break; 1576 } 1577 1578 // Return true if we can skip handling the Target function reference. 1579 auto ignoreFunctionRef = [&](const BinaryFunction &Target) { 1580 if (&Target == this) 1581 return true; 1582 1583 // Note that later we may decide not to emit Target function. In that 1584 // case, we conservatively create references that will be ignored or 1585 // resolved to the same function. 1586 if (!BC.shouldEmit(Target)) 1587 return true; 1588 1589 return false; 1590 }; 1591 1592 // Return true if we can ignore reference to the symbol. 1593 auto ignoreReference = [&](const MCSymbol *TargetSymbol) { 1594 if (!TargetSymbol) 1595 return true; 1596 1597 if (BC.forceSymbolRelocations(TargetSymbol->getName())) 1598 return false; 1599 1600 BinaryFunction *TargetFunction = BC.getFunctionForSymbol(TargetSymbol); 1601 if (!TargetFunction) 1602 return true; 1603 1604 return ignoreFunctionRef(*TargetFunction); 1605 }; 1606 1607 // Handle calls and branches separately as symbolization doesn't work for 1608 // them yet. 1609 MCSymbol *BranchTargetSymbol = nullptr; 1610 if (BC.MIB->isCall(Instruction) || BC.MIB->isBranch(Instruction)) { 1611 uint64_t TargetAddress = 0; 1612 BC.MIB->evaluateBranch(Instruction, AbsoluteInstrAddr, Size, 1613 TargetAddress); 1614 1615 // Create an entry point at reference address if needed. 1616 BinaryFunction *TargetFunction = 1617 BC.getBinaryFunctionContainingAddress(TargetAddress); 1618 1619 if (!TargetFunction || ignoreFunctionRef(*TargetFunction)) 1620 continue; 1621 1622 const uint64_t FunctionOffset = 1623 TargetAddress - TargetFunction->getAddress(); 1624 BranchTargetSymbol = 1625 FunctionOffset ? TargetFunction->addEntryPointAtOffset(FunctionOffset) 1626 : TargetFunction->getSymbol(); 1627 } 1628 1629 // Can't find more references. Not creating relocations since we are not 1630 // moving code. 1631 if (!BC.HasRelocations) 1632 continue; 1633 1634 if (BranchTargetSymbol) { 1635 BC.MIB->replaceBranchTarget(Instruction, BranchTargetSymbol, 1636 Emitter.LocalCtx.get()); 1637 } else if (!llvm::any_of(Instruction, 1638 [](const MCOperand &Op) { return Op.isExpr(); })) { 1639 // Skip assembly if the instruction may not have any symbolic operands. 1640 continue; 1641 } else { 1642 analyzeInstructionForFuncReference(Instruction); 1643 } 1644 1645 // Emit the instruction using temp emitter and generate relocations. 1646 SmallString<256> Code; 1647 SmallVector<MCFixup, 4> Fixups; 1648 Emitter.MCE->encodeInstruction(Instruction, Code, Fixups, *BC.STI); 1649 1650 // Create relocation for every fixup. 1651 for (const MCFixup &Fixup : Fixups) { 1652 std::optional<Relocation> Rel = BC.MIB->createRelocation(Fixup, *BC.MAB); 1653 if (!Rel) { 1654 Success = false; 1655 continue; 1656 } 1657 1658 if (ignoreReference(Rel->Symbol)) 1659 continue; 1660 1661 if (Relocation::getSizeForType(Rel->Type) < 4) { 1662 // If the instruction uses a short form, then we might not be able 1663 // to handle the rewrite without relaxation, and hence cannot reliably 1664 // create an external reference relocation. 1665 Success = false; 1666 continue; 1667 } 1668 Rel->Offset += getAddress() - getOriginSection()->getAddress() + Offset; 1669 FunctionRelocations.push_back(*Rel); 1670 } 1671 1672 if (!Success) 1673 break; 1674 } 1675 1676 // Reset symbolizer for the disassembler. 1677 BC.SymbolicDisAsm->setSymbolizer(nullptr); 1678 1679 // Add relocations unless disassembly failed for this function. 1680 if (!DisassemblyFailed) 1681 for (Relocation &Rel : FunctionRelocations) 1682 getOriginSection()->addPendingRelocation(Rel); 1683 1684 // Inform BinaryContext that this function symbols will not be defined and 1685 // relocations should not be created against them. 1686 if (BC.HasRelocations) { 1687 for (std::pair<const uint32_t, MCSymbol *> &LI : Labels) 1688 BC.UndefinedSymbols.insert(LI.second); 1689 for (MCSymbol *const EndLabel : FunctionEndLabels) 1690 if (EndLabel) 1691 BC.UndefinedSymbols.insert(EndLabel); 1692 } 1693 1694 clearList(Relocations); 1695 clearList(ExternallyReferencedOffsets); 1696 1697 if (Success && BC.HasRelocations) 1698 HasExternalRefRelocations = true; 1699 1700 if (opts::Verbosity >= 1 && !Success) 1701 BC.outs() << "BOLT-INFO: failed to scan refs for " << *this << '\n'; 1702 1703 return Success; 1704 } 1705 1706 void BinaryFunction::postProcessEntryPoints() { 1707 if (!isSimple()) 1708 return; 1709 1710 for (auto &KV : Labels) { 1711 MCSymbol *Label = KV.second; 1712 if (!getSecondaryEntryPointSymbol(Label)) 1713 continue; 1714 1715 // In non-relocation mode there's potentially an external undetectable 1716 // reference to the entry point and hence we cannot move this entry 1717 // point. Optimizing without moving could be difficult. 1718 // In BAT mode, register any known entry points for CFG construction. 1719 if (!BC.HasRelocations && !BC.HasBATSection) 1720 setSimple(false); 1721 1722 const uint32_t Offset = KV.first; 1723 1724 // If we are at Offset 0 and there is no instruction associated with it, 1725 // this means this is an empty function. Just ignore. If we find an 1726 // instruction at this offset, this entry point is valid. 1727 if (!Offset || getInstructionAtOffset(Offset)) 1728 continue; 1729 1730 // On AArch64 there are legitimate reasons to have references past the 1731 // end of the function, e.g. jump tables. 1732 if (BC.isAArch64() && Offset == getSize()) 1733 continue; 1734 1735 BC.errs() << "BOLT-WARNING: reference in the middle of instruction " 1736 "detected in function " 1737 << *this << " at offset 0x" << Twine::utohexstr(Offset) << '\n'; 1738 if (BC.HasRelocations) 1739 setIgnored(); 1740 setSimple(false); 1741 return; 1742 } 1743 } 1744 1745 void BinaryFunction::postProcessJumpTables() { 1746 // Create labels for all entries. 1747 for (auto &JTI : JumpTables) { 1748 JumpTable &JT = *JTI.second; 1749 if (JT.Type == JumpTable::JTT_PIC && opts::JumpTables == JTS_BASIC) { 1750 opts::JumpTables = JTS_MOVE; 1751 BC.outs() << "BOLT-INFO: forcing -jump-tables=move as PIC jump table was " 1752 "detected in function " 1753 << *this << '\n'; 1754 } 1755 const uint64_t BDSize = 1756 BC.getBinaryDataAtAddress(JT.getAddress())->getSize(); 1757 if (!BDSize) { 1758 BC.setBinaryDataSize(JT.getAddress(), JT.getSize()); 1759 } else { 1760 assert(BDSize >= JT.getSize() && 1761 "jump table cannot be larger than the containing object"); 1762 } 1763 if (!JT.Entries.empty()) 1764 continue; 1765 1766 bool HasOneParent = (JT.Parents.size() == 1); 1767 for (uint64_t EntryAddress : JT.EntriesAsAddress) { 1768 // builtin_unreachable does not belong to any function 1769 // Need to handle separately 1770 bool IsBuiltinUnreachable = 1771 llvm::any_of(JT.Parents, [&](const BinaryFunction *Parent) { 1772 return EntryAddress == Parent->getAddress() + Parent->getSize(); 1773 }); 1774 if (IsBuiltinUnreachable) { 1775 MCSymbol *Label = getOrCreateLocalLabel(EntryAddress, true); 1776 JT.Entries.push_back(Label); 1777 continue; 1778 } 1779 // Create a local label for targets that cannot be reached by other 1780 // fragments. Otherwise, create a secondary entry point in the target 1781 // function. 1782 BinaryFunction *TargetBF = 1783 BC.getBinaryFunctionContainingAddress(EntryAddress); 1784 MCSymbol *Label; 1785 if (HasOneParent && TargetBF == this) { 1786 Label = getOrCreateLocalLabel(EntryAddress, true); 1787 } else { 1788 const uint64_t Offset = EntryAddress - TargetBF->getAddress(); 1789 Label = Offset ? TargetBF->addEntryPointAtOffset(Offset) 1790 : TargetBF->getSymbol(); 1791 } 1792 JT.Entries.push_back(Label); 1793 } 1794 } 1795 1796 // Add TakenBranches from JumpTables. 1797 // 1798 // We want to do it after initial processing since we don't know jump tables' 1799 // boundaries until we process them all. 1800 for (auto &JTSite : JTSites) { 1801 const uint64_t JTSiteOffset = JTSite.first; 1802 const uint64_t JTAddress = JTSite.second; 1803 const JumpTable *JT = getJumpTableContainingAddress(JTAddress); 1804 assert(JT && "cannot find jump table for address"); 1805 1806 uint64_t EntryOffset = JTAddress - JT->getAddress(); 1807 while (EntryOffset < JT->getSize()) { 1808 uint64_t EntryAddress = JT->EntriesAsAddress[EntryOffset / JT->EntrySize]; 1809 uint64_t TargetOffset = EntryAddress - getAddress(); 1810 if (TargetOffset < getSize()) { 1811 TakenBranches.emplace_back(JTSiteOffset, TargetOffset); 1812 1813 if (opts::StrictMode) 1814 registerReferencedOffset(TargetOffset); 1815 } 1816 1817 EntryOffset += JT->EntrySize; 1818 1819 // A label at the next entry means the end of this jump table. 1820 if (JT->Labels.count(EntryOffset)) 1821 break; 1822 } 1823 } 1824 clearList(JTSites); 1825 1826 // Conservatively populate all possible destinations for unknown indirect 1827 // branches. 1828 if (opts::StrictMode && hasInternalReference()) { 1829 for (uint64_t Offset : UnknownIndirectBranchOffsets) { 1830 for (uint64_t PossibleDestination : ExternallyReferencedOffsets) { 1831 // Ignore __builtin_unreachable(). 1832 if (PossibleDestination == getSize()) 1833 continue; 1834 TakenBranches.emplace_back(Offset, PossibleDestination); 1835 } 1836 } 1837 } 1838 } 1839 1840 bool BinaryFunction::validateExternallyReferencedOffsets() { 1841 SmallPtrSet<MCSymbol *, 4> JTTargets; 1842 for (const JumpTable *JT : llvm::make_second_range(JumpTables)) 1843 JTTargets.insert(JT->Entries.begin(), JT->Entries.end()); 1844 1845 bool HasUnclaimedReference = false; 1846 for (uint64_t Destination : ExternallyReferencedOffsets) { 1847 // Ignore __builtin_unreachable(). 1848 if (Destination == getSize()) 1849 continue; 1850 // Ignore constant islands 1851 if (isInConstantIsland(Destination + getAddress())) 1852 continue; 1853 1854 if (BinaryBasicBlock *BB = getBasicBlockAtOffset(Destination)) { 1855 // Check if the externally referenced offset is a recognized jump table 1856 // target. 1857 if (JTTargets.contains(BB->getLabel())) 1858 continue; 1859 1860 if (opts::Verbosity >= 1) { 1861 BC.errs() << "BOLT-WARNING: unclaimed data to code reference (possibly " 1862 << "an unrecognized jump table entry) to " << BB->getName() 1863 << " in " << *this << "\n"; 1864 } 1865 auto L = BC.scopeLock(); 1866 addEntryPoint(*BB); 1867 } else { 1868 BC.errs() << "BOLT-WARNING: unknown data to code reference to offset " 1869 << Twine::utohexstr(Destination) << " in " << *this << "\n"; 1870 setIgnored(); 1871 } 1872 HasUnclaimedReference = true; 1873 } 1874 return !HasUnclaimedReference; 1875 } 1876 1877 bool BinaryFunction::postProcessIndirectBranches( 1878 MCPlusBuilder::AllocatorIdTy AllocId) { 1879 auto addUnknownControlFlow = [&](BinaryBasicBlock &BB) { 1880 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: adding unknown control flow in " << *this 1881 << " for " << BB.getName() << "\n"); 1882 HasUnknownControlFlow = true; 1883 BB.removeAllSuccessors(); 1884 for (uint64_t PossibleDestination : ExternallyReferencedOffsets) 1885 if (BinaryBasicBlock *SuccBB = getBasicBlockAtOffset(PossibleDestination)) 1886 BB.addSuccessor(SuccBB); 1887 }; 1888 1889 uint64_t NumIndirectJumps = 0; 1890 MCInst *LastIndirectJump = nullptr; 1891 BinaryBasicBlock *LastIndirectJumpBB = nullptr; 1892 uint64_t LastJT = 0; 1893 uint16_t LastJTIndexReg = BC.MIB->getNoRegister(); 1894 for (BinaryBasicBlock &BB : blocks()) { 1895 for (BinaryBasicBlock::iterator II = BB.begin(); II != BB.end(); ++II) { 1896 MCInst &Instr = *II; 1897 if (!BC.MIB->isIndirectBranch(Instr)) 1898 continue; 1899 1900 // If there's an indirect branch in a single-block function - 1901 // it must be a tail call. 1902 if (BasicBlocks.size() == 1) { 1903 BC.MIB->convertJmpToTailCall(Instr); 1904 return true; 1905 } 1906 1907 ++NumIndirectJumps; 1908 1909 if (opts::StrictMode && !hasInternalReference()) { 1910 BC.MIB->convertJmpToTailCall(Instr); 1911 break; 1912 } 1913 1914 // Validate the tail call or jump table assumptions now that we know 1915 // basic block boundaries. 1916 if (BC.MIB->isTailCall(Instr) || BC.MIB->getJumpTable(Instr)) { 1917 const unsigned PtrSize = BC.AsmInfo->getCodePointerSize(); 1918 MCInst *MemLocInstr; 1919 unsigned BaseRegNum, IndexRegNum; 1920 int64_t DispValue; 1921 const MCExpr *DispExpr; 1922 MCInst *PCRelBaseInstr; 1923 MCInst *FixedEntryLoadInstr; 1924 IndirectBranchType Type = BC.MIB->analyzeIndirectBranch( 1925 Instr, BB.begin(), II, PtrSize, MemLocInstr, BaseRegNum, 1926 IndexRegNum, DispValue, DispExpr, PCRelBaseInstr, 1927 FixedEntryLoadInstr); 1928 if (Type != IndirectBranchType::UNKNOWN || MemLocInstr != nullptr) 1929 continue; 1930 1931 if (!opts::StrictMode) 1932 return false; 1933 1934 if (BC.MIB->isTailCall(Instr)) { 1935 BC.MIB->convertTailCallToJmp(Instr); 1936 } else { 1937 LastIndirectJump = &Instr; 1938 LastIndirectJumpBB = &BB; 1939 LastJT = BC.MIB->getJumpTable(Instr); 1940 LastJTIndexReg = BC.MIB->getJumpTableIndexReg(Instr); 1941 BC.MIB->unsetJumpTable(Instr); 1942 1943 JumpTable *JT = BC.getJumpTableContainingAddress(LastJT); 1944 if (JT->Type == JumpTable::JTT_NORMAL) { 1945 // Invalidating the jump table may also invalidate other jump table 1946 // boundaries. Until we have/need a support for this, mark the 1947 // function as non-simple. 1948 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: rejected jump table reference" 1949 << JT->getName() << " in " << *this << '\n'); 1950 return false; 1951 } 1952 } 1953 1954 addUnknownControlFlow(BB); 1955 continue; 1956 } 1957 1958 // If this block contains an epilogue code and has an indirect branch, 1959 // then most likely it's a tail call. Otherwise, we cannot tell for sure 1960 // what it is and conservatively reject the function's CFG. 1961 bool IsEpilogue = llvm::any_of(BB, [&](const MCInst &Instr) { 1962 return BC.MIB->isLeave(Instr) || BC.MIB->isPop(Instr); 1963 }); 1964 if (IsEpilogue) { 1965 BC.MIB->convertJmpToTailCall(Instr); 1966 BB.removeAllSuccessors(); 1967 continue; 1968 } 1969 1970 if (opts::Verbosity >= 2) { 1971 BC.outs() << "BOLT-INFO: rejected potential indirect tail call in " 1972 << "function " << *this << " in basic block " << BB.getName() 1973 << ".\n"; 1974 LLVM_DEBUG(BC.printInstructions(dbgs(), BB.begin(), BB.end(), 1975 BB.getOffset(), this, true)); 1976 } 1977 1978 if (!opts::StrictMode) 1979 return false; 1980 1981 addUnknownControlFlow(BB); 1982 } 1983 } 1984 1985 if (HasInternalLabelReference) 1986 return false; 1987 1988 // If there's only one jump table, and one indirect jump, and no other 1989 // references, then we should be able to derive the jump table even if we 1990 // fail to match the pattern. 1991 if (HasUnknownControlFlow && NumIndirectJumps == 1 && 1992 JumpTables.size() == 1 && LastIndirectJump && 1993 !BC.getJumpTableContainingAddress(LastJT)->IsSplit) { 1994 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: unsetting unknown control flow in " 1995 << *this << '\n'); 1996 BC.MIB->setJumpTable(*LastIndirectJump, LastJT, LastJTIndexReg, AllocId); 1997 HasUnknownControlFlow = false; 1998 1999 LastIndirectJumpBB->updateJumpTableSuccessors(); 2000 } 2001 2002 // Validate that all data references to function offsets are claimed by 2003 // recognized jump tables. Register externally referenced blocks as entry 2004 // points. 2005 if (!opts::StrictMode && hasInternalReference()) { 2006 if (!validateExternallyReferencedOffsets()) 2007 return false; 2008 } 2009 2010 if (HasUnknownControlFlow && !BC.HasRelocations) 2011 return false; 2012 2013 return true; 2014 } 2015 2016 void BinaryFunction::recomputeLandingPads() { 2017 updateBBIndices(0); 2018 2019 for (BinaryBasicBlock *BB : BasicBlocks) { 2020 BB->LandingPads.clear(); 2021 BB->Throwers.clear(); 2022 } 2023 2024 for (BinaryBasicBlock *BB : BasicBlocks) { 2025 std::unordered_set<const BinaryBasicBlock *> BBLandingPads; 2026 for (MCInst &Instr : *BB) { 2027 if (!BC.MIB->isInvoke(Instr)) 2028 continue; 2029 2030 const std::optional<MCPlus::MCLandingPad> EHInfo = 2031 BC.MIB->getEHInfo(Instr); 2032 if (!EHInfo || !EHInfo->first) 2033 continue; 2034 2035 BinaryBasicBlock *LPBlock = getBasicBlockForLabel(EHInfo->first); 2036 if (!BBLandingPads.count(LPBlock)) { 2037 BBLandingPads.insert(LPBlock); 2038 BB->LandingPads.emplace_back(LPBlock); 2039 LPBlock->Throwers.emplace_back(BB); 2040 } 2041 } 2042 } 2043 } 2044 2045 Error BinaryFunction::buildCFG(MCPlusBuilder::AllocatorIdTy AllocatorId) { 2046 auto &MIB = BC.MIB; 2047 2048 if (!isSimple()) { 2049 assert(!BC.HasRelocations && 2050 "cannot process file with non-simple function in relocs mode"); 2051 return createNonFatalBOLTError(""); 2052 } 2053 2054 if (CurrentState != State::Disassembled) 2055 return createNonFatalBOLTError(""); 2056 2057 assert(BasicBlocks.empty() && "basic block list should be empty"); 2058 assert((Labels.find(getFirstInstructionOffset()) != Labels.end()) && 2059 "first instruction should always have a label"); 2060 2061 // Create basic blocks in the original layout order: 2062 // 2063 // * Every instruction with associated label marks 2064 // the beginning of a basic block. 2065 // * Conditional instruction marks the end of a basic block, 2066 // except when the following instruction is an 2067 // unconditional branch, and the unconditional branch is not 2068 // a destination of another branch. In the latter case, the 2069 // basic block will consist of a single unconditional branch 2070 // (missed "double-jump" optimization). 2071 // 2072 // Created basic blocks are sorted in layout order since they are 2073 // created in the same order as instructions, and instructions are 2074 // sorted by offsets. 2075 BinaryBasicBlock *InsertBB = nullptr; 2076 BinaryBasicBlock *PrevBB = nullptr; 2077 bool IsLastInstrNop = false; 2078 // Offset of the last non-nop instruction. 2079 uint64_t LastInstrOffset = 0; 2080 2081 auto addCFIPlaceholders = [this](uint64_t CFIOffset, 2082 BinaryBasicBlock *InsertBB) { 2083 for (auto FI = OffsetToCFI.lower_bound(CFIOffset), 2084 FE = OffsetToCFI.upper_bound(CFIOffset); 2085 FI != FE; ++FI) { 2086 addCFIPseudo(InsertBB, InsertBB->end(), FI->second); 2087 } 2088 }; 2089 2090 // For profiling purposes we need to save the offset of the last instruction 2091 // in the basic block. 2092 // NOTE: nops always have an Offset annotation. Annotate the last non-nop as 2093 // older profiles ignored nops. 2094 auto updateOffset = [&](uint64_t Offset) { 2095 assert(PrevBB && PrevBB != InsertBB && "invalid previous block"); 2096 MCInst *LastNonNop = nullptr; 2097 for (BinaryBasicBlock::reverse_iterator RII = PrevBB->getLastNonPseudo(), 2098 E = PrevBB->rend(); 2099 RII != E; ++RII) { 2100 if (!BC.MIB->isPseudo(*RII) && !BC.MIB->isNoop(*RII)) { 2101 LastNonNop = &*RII; 2102 break; 2103 } 2104 } 2105 if (LastNonNop && !MIB->getOffset(*LastNonNop)) 2106 MIB->setOffset(*LastNonNop, static_cast<uint32_t>(Offset)); 2107 }; 2108 2109 for (auto I = Instructions.begin(), E = Instructions.end(); I != E; ++I) { 2110 const uint32_t Offset = I->first; 2111 MCInst &Instr = I->second; 2112 2113 auto LI = Labels.find(Offset); 2114 if (LI != Labels.end()) { 2115 // Always create new BB at branch destination. 2116 PrevBB = InsertBB ? InsertBB : PrevBB; 2117 InsertBB = addBasicBlockAt(LI->first, LI->second); 2118 if (opts::PreserveBlocksAlignment && IsLastInstrNop) 2119 InsertBB->setDerivedAlignment(); 2120 2121 if (PrevBB) 2122 updateOffset(LastInstrOffset); 2123 } 2124 2125 // Mark all nops with Offset for profile tracking purposes. 2126 if (MIB->isNoop(Instr) && !MIB->getOffset(Instr)) { 2127 // If "Offset" annotation is not present, set it and mark the nop for 2128 // deletion. 2129 MIB->setOffset(Instr, static_cast<uint32_t>(Offset)); 2130 // Annotate ordinary nops, so we can safely delete them if required. 2131 MIB->addAnnotation(Instr, "NOP", static_cast<uint32_t>(1), AllocatorId); 2132 } 2133 2134 if (!InsertBB) { 2135 // It must be a fallthrough or unreachable code. Create a new block unless 2136 // we see an unconditional branch following a conditional one. The latter 2137 // should not be a conditional tail call. 2138 assert(PrevBB && "no previous basic block for a fall through"); 2139 MCInst *PrevInstr = PrevBB->getLastNonPseudoInstr(); 2140 assert(PrevInstr && "no previous instruction for a fall through"); 2141 if (MIB->isUnconditionalBranch(Instr) && 2142 !MIB->isIndirectBranch(*PrevInstr) && 2143 !MIB->isUnconditionalBranch(*PrevInstr) && 2144 !MIB->getConditionalTailCall(*PrevInstr) && 2145 !MIB->isReturn(*PrevInstr)) { 2146 // Temporarily restore inserter basic block. 2147 InsertBB = PrevBB; 2148 } else { 2149 MCSymbol *Label; 2150 { 2151 auto L = BC.scopeLock(); 2152 Label = BC.Ctx->createNamedTempSymbol("FT"); 2153 } 2154 InsertBB = addBasicBlockAt(Offset, Label); 2155 if (opts::PreserveBlocksAlignment && IsLastInstrNop) 2156 InsertBB->setDerivedAlignment(); 2157 updateOffset(LastInstrOffset); 2158 } 2159 } 2160 if (Offset == getFirstInstructionOffset()) { 2161 // Add associated CFI pseudos in the first offset 2162 addCFIPlaceholders(Offset, InsertBB); 2163 } 2164 2165 const bool IsBlockEnd = MIB->isTerminator(Instr); 2166 IsLastInstrNop = MIB->isNoop(Instr); 2167 if (!IsLastInstrNop) 2168 LastInstrOffset = Offset; 2169 InsertBB->addInstruction(std::move(Instr)); 2170 2171 // Add associated CFI instrs. We always add the CFI instruction that is 2172 // located immediately after this instruction, since the next CFI 2173 // instruction reflects the change in state caused by this instruction. 2174 auto NextInstr = std::next(I); 2175 uint64_t CFIOffset; 2176 if (NextInstr != E) 2177 CFIOffset = NextInstr->first; 2178 else 2179 CFIOffset = getSize(); 2180 2181 // Note: this potentially invalidates instruction pointers/iterators. 2182 addCFIPlaceholders(CFIOffset, InsertBB); 2183 2184 if (IsBlockEnd) { 2185 PrevBB = InsertBB; 2186 InsertBB = nullptr; 2187 } 2188 } 2189 2190 if (BasicBlocks.empty()) { 2191 setSimple(false); 2192 return createNonFatalBOLTError(""); 2193 } 2194 2195 // Intermediate dump. 2196 LLVM_DEBUG(print(dbgs(), "after creating basic blocks")); 2197 2198 // TODO: handle properly calls to no-return functions, 2199 // e.g. exit(3), etc. Otherwise we'll see a false fall-through 2200 // blocks. 2201 2202 // Remove duplicates branches. We can get a bunch of them from jump tables. 2203 // Without doing jump table value profiling we don't have a use for extra 2204 // (duplicate) branches. 2205 llvm::sort(TakenBranches); 2206 auto NewEnd = std::unique(TakenBranches.begin(), TakenBranches.end()); 2207 TakenBranches.erase(NewEnd, TakenBranches.end()); 2208 2209 for (std::pair<uint32_t, uint32_t> &Branch : TakenBranches) { 2210 LLVM_DEBUG(dbgs() << "registering branch [0x" 2211 << Twine::utohexstr(Branch.first) << "] -> [0x" 2212 << Twine::utohexstr(Branch.second) << "]\n"); 2213 BinaryBasicBlock *FromBB = getBasicBlockContainingOffset(Branch.first); 2214 BinaryBasicBlock *ToBB = getBasicBlockAtOffset(Branch.second); 2215 if (!FromBB || !ToBB) { 2216 if (!FromBB) 2217 BC.errs() << "BOLT-ERROR: cannot find BB containing the branch.\n"; 2218 if (!ToBB) 2219 BC.errs() 2220 << "BOLT-ERROR: cannot find BB containing branch destination.\n"; 2221 return createFatalBOLTError(BC.generateBugReportMessage( 2222 "disassembly failed - inconsistent branch found.", *this)); 2223 } 2224 2225 FromBB->addSuccessor(ToBB); 2226 } 2227 2228 // Add fall-through branches. 2229 PrevBB = nullptr; 2230 bool IsPrevFT = false; // Is previous block a fall-through. 2231 for (BinaryBasicBlock *BB : BasicBlocks) { 2232 if (IsPrevFT) 2233 PrevBB->addSuccessor(BB); 2234 2235 if (BB->empty()) { 2236 IsPrevFT = true; 2237 PrevBB = BB; 2238 continue; 2239 } 2240 2241 MCInst *LastInstr = BB->getLastNonPseudoInstr(); 2242 assert(LastInstr && 2243 "should have non-pseudo instruction in non-empty block"); 2244 2245 if (BB->succ_size() == 0) { 2246 // Since there's no existing successors, we know the last instruction is 2247 // not a conditional branch. Thus if it's a terminator, it shouldn't be a 2248 // fall-through. 2249 // 2250 // Conditional tail call is a special case since we don't add a taken 2251 // branch successor for it. 2252 IsPrevFT = !MIB->isTerminator(*LastInstr) || 2253 MIB->getConditionalTailCall(*LastInstr); 2254 } else if (BB->succ_size() == 1) { 2255 IsPrevFT = MIB->isConditionalBranch(*LastInstr); 2256 } else { 2257 IsPrevFT = false; 2258 } 2259 2260 PrevBB = BB; 2261 } 2262 2263 // Assign landing pads and throwers info. 2264 recomputeLandingPads(); 2265 2266 // Assign CFI information to each BB entry. 2267 annotateCFIState(); 2268 2269 // Annotate invoke instructions with GNU_args_size data. 2270 propagateGnuArgsSizeInfo(AllocatorId); 2271 2272 // Set the basic block layout to the original order and set end offsets. 2273 PrevBB = nullptr; 2274 for (BinaryBasicBlock *BB : BasicBlocks) { 2275 Layout.addBasicBlock(BB); 2276 if (PrevBB) 2277 PrevBB->setEndOffset(BB->getOffset()); 2278 PrevBB = BB; 2279 } 2280 PrevBB->setEndOffset(getSize()); 2281 2282 Layout.updateLayoutIndices(); 2283 2284 normalizeCFIState(); 2285 2286 // Clean-up memory taken by intermediate structures. 2287 // 2288 // NB: don't clear Labels list as we may need them if we mark the function 2289 // as non-simple later in the process of discovering extra entry points. 2290 clearList(Instructions); 2291 clearList(OffsetToCFI); 2292 clearList(TakenBranches); 2293 2294 // Update the state. 2295 CurrentState = State::CFG; 2296 2297 // Make any necessary adjustments for indirect branches. 2298 if (!postProcessIndirectBranches(AllocatorId)) { 2299 if (opts::Verbosity) { 2300 BC.errs() << "BOLT-WARNING: failed to post-process indirect branches for " 2301 << *this << '\n'; 2302 } 2303 // In relocation mode we want to keep processing the function but avoid 2304 // optimizing it. 2305 setSimple(false); 2306 } 2307 2308 clearList(ExternallyReferencedOffsets); 2309 clearList(UnknownIndirectBranchOffsets); 2310 2311 return Error::success(); 2312 } 2313 2314 void BinaryFunction::postProcessCFG() { 2315 if (isSimple() && !BasicBlocks.empty()) { 2316 // Convert conditional tail call branches to conditional branches that jump 2317 // to a tail call. 2318 removeConditionalTailCalls(); 2319 2320 postProcessProfile(); 2321 2322 // Eliminate inconsistencies between branch instructions and CFG. 2323 postProcessBranches(); 2324 } 2325 2326 // The final cleanup of intermediate structures. 2327 clearList(IgnoredBranches); 2328 2329 // Remove "Offset" annotations, unless we need an address-translation table 2330 // later. This has no cost, since annotations are allocated by a bumpptr 2331 // allocator and won't be released anyway until late in the pipeline. 2332 if (!requiresAddressTranslation() && !opts::Instrument) { 2333 for (BinaryBasicBlock &BB : blocks()) 2334 for (MCInst &Inst : BB) 2335 BC.MIB->clearOffset(Inst); 2336 } 2337 2338 assert((!isSimple() || validateCFG()) && 2339 "invalid CFG detected after post-processing"); 2340 } 2341 2342 void BinaryFunction::removeTagsFromProfile() { 2343 for (BinaryBasicBlock *BB : BasicBlocks) { 2344 if (BB->ExecutionCount == BinaryBasicBlock::COUNT_NO_PROFILE) 2345 BB->ExecutionCount = 0; 2346 for (BinaryBasicBlock::BinaryBranchInfo &BI : BB->branch_info()) { 2347 if (BI.Count != BinaryBasicBlock::COUNT_NO_PROFILE && 2348 BI.MispredictedCount != BinaryBasicBlock::COUNT_NO_PROFILE) 2349 continue; 2350 BI.Count = 0; 2351 BI.MispredictedCount = 0; 2352 } 2353 } 2354 } 2355 2356 void BinaryFunction::removeConditionalTailCalls() { 2357 // Blocks to be appended at the end. 2358 std::vector<std::unique_ptr<BinaryBasicBlock>> NewBlocks; 2359 2360 for (auto BBI = begin(); BBI != end(); ++BBI) { 2361 BinaryBasicBlock &BB = *BBI; 2362 MCInst *CTCInstr = BB.getLastNonPseudoInstr(); 2363 if (!CTCInstr) 2364 continue; 2365 2366 std::optional<uint64_t> TargetAddressOrNone = 2367 BC.MIB->getConditionalTailCall(*CTCInstr); 2368 if (!TargetAddressOrNone) 2369 continue; 2370 2371 // Gather all necessary information about CTC instruction before 2372 // annotations are destroyed. 2373 const int32_t CFIStateBeforeCTC = BB.getCFIStateAtInstr(CTCInstr); 2374 uint64_t CTCTakenCount = BinaryBasicBlock::COUNT_NO_PROFILE; 2375 uint64_t CTCMispredCount = BinaryBasicBlock::COUNT_NO_PROFILE; 2376 if (hasValidProfile()) { 2377 CTCTakenCount = BC.MIB->getAnnotationWithDefault<uint64_t>( 2378 *CTCInstr, "CTCTakenCount"); 2379 CTCMispredCount = BC.MIB->getAnnotationWithDefault<uint64_t>( 2380 *CTCInstr, "CTCMispredCount"); 2381 } 2382 2383 // Assert that the tail call does not throw. 2384 assert(!BC.MIB->getEHInfo(*CTCInstr) && 2385 "found tail call with associated landing pad"); 2386 2387 // Create a basic block with an unconditional tail call instruction using 2388 // the same destination. 2389 const MCSymbol *CTCTargetLabel = BC.MIB->getTargetSymbol(*CTCInstr); 2390 assert(CTCTargetLabel && "symbol expected for conditional tail call"); 2391 MCInst TailCallInstr; 2392 BC.MIB->createTailCall(TailCallInstr, CTCTargetLabel, BC.Ctx.get()); 2393 2394 // Move offset from CTCInstr to TailCallInstr. 2395 if (const std::optional<uint32_t> Offset = BC.MIB->getOffset(*CTCInstr)) { 2396 BC.MIB->setOffset(TailCallInstr, *Offset); 2397 BC.MIB->clearOffset(*CTCInstr); 2398 } 2399 2400 // Link new BBs to the original input offset of the BB where the CTC 2401 // is, so we can map samples recorded in new BBs back to the original BB 2402 // seem in the input binary (if using BAT) 2403 std::unique_ptr<BinaryBasicBlock> TailCallBB = 2404 createBasicBlock(BC.Ctx->createNamedTempSymbol("TC")); 2405 TailCallBB->setOffset(BB.getInputOffset()); 2406 TailCallBB->addInstruction(TailCallInstr); 2407 TailCallBB->setCFIState(CFIStateBeforeCTC); 2408 2409 // Add CFG edge with profile info from BB to TailCallBB. 2410 BB.addSuccessor(TailCallBB.get(), CTCTakenCount, CTCMispredCount); 2411 2412 // Add execution count for the block. 2413 TailCallBB->setExecutionCount(CTCTakenCount); 2414 2415 BC.MIB->convertTailCallToJmp(*CTCInstr); 2416 2417 BC.MIB->replaceBranchTarget(*CTCInstr, TailCallBB->getLabel(), 2418 BC.Ctx.get()); 2419 2420 // Add basic block to the list that will be added to the end. 2421 NewBlocks.emplace_back(std::move(TailCallBB)); 2422 2423 // Swap edges as the TailCallBB corresponds to the taken branch. 2424 BB.swapConditionalSuccessors(); 2425 2426 // This branch is no longer a conditional tail call. 2427 BC.MIB->unsetConditionalTailCall(*CTCInstr); 2428 } 2429 2430 insertBasicBlocks(std::prev(end()), std::move(NewBlocks), 2431 /* UpdateLayout */ true, 2432 /* UpdateCFIState */ false); 2433 } 2434 2435 uint64_t BinaryFunction::getFunctionScore() const { 2436 if (FunctionScore != -1) 2437 return FunctionScore; 2438 2439 if (!isSimple() || !hasValidProfile()) { 2440 FunctionScore = 0; 2441 return FunctionScore; 2442 } 2443 2444 uint64_t TotalScore = 0ULL; 2445 for (const BinaryBasicBlock &BB : blocks()) { 2446 uint64_t BBExecCount = BB.getExecutionCount(); 2447 if (BBExecCount == BinaryBasicBlock::COUNT_NO_PROFILE) 2448 continue; 2449 TotalScore += BBExecCount * BB.getNumNonPseudos(); 2450 } 2451 FunctionScore = TotalScore; 2452 return FunctionScore; 2453 } 2454 2455 void BinaryFunction::annotateCFIState() { 2456 assert(CurrentState == State::Disassembled && "unexpected function state"); 2457 assert(!BasicBlocks.empty() && "basic block list should not be empty"); 2458 2459 // This is an index of the last processed CFI in FDE CFI program. 2460 uint32_t State = 0; 2461 2462 // This is an index of RememberState CFI reflecting effective state right 2463 // after execution of RestoreState CFI. 2464 // 2465 // It differs from State iff the CFI at (State-1) 2466 // was RestoreState (modulo GNU_args_size CFIs, which are ignored). 2467 // 2468 // This allows us to generate shorter replay sequences when producing new 2469 // CFI programs. 2470 uint32_t EffectiveState = 0; 2471 2472 // For tracking RememberState/RestoreState sequences. 2473 std::stack<uint32_t> StateStack; 2474 2475 for (BinaryBasicBlock *BB : BasicBlocks) { 2476 BB->setCFIState(EffectiveState); 2477 2478 for (const MCInst &Instr : *BB) { 2479 const MCCFIInstruction *CFI = getCFIFor(Instr); 2480 if (!CFI) 2481 continue; 2482 2483 ++State; 2484 2485 switch (CFI->getOperation()) { 2486 case MCCFIInstruction::OpRememberState: 2487 StateStack.push(EffectiveState); 2488 EffectiveState = State; 2489 break; 2490 case MCCFIInstruction::OpRestoreState: 2491 assert(!StateStack.empty() && "corrupt CFI stack"); 2492 EffectiveState = StateStack.top(); 2493 StateStack.pop(); 2494 break; 2495 case MCCFIInstruction::OpGnuArgsSize: 2496 // OpGnuArgsSize CFIs do not affect the CFI state. 2497 break; 2498 default: 2499 // Any other CFI updates the state. 2500 EffectiveState = State; 2501 break; 2502 } 2503 } 2504 } 2505 2506 if (opts::Verbosity >= 1 && !StateStack.empty()) { 2507 BC.errs() << "BOLT-WARNING: non-empty CFI stack at the end of " << *this 2508 << '\n'; 2509 } 2510 } 2511 2512 namespace { 2513 2514 /// Our full interpretation of a DWARF CFI machine state at a given point 2515 struct CFISnapshot { 2516 /// CFA register number and offset defining the canonical frame at this 2517 /// point, or the number of a rule (CFI state) that computes it with a 2518 /// DWARF expression. This number will be negative if it refers to a CFI 2519 /// located in the CIE instead of the FDE. 2520 uint32_t CFAReg; 2521 int32_t CFAOffset; 2522 int32_t CFARule; 2523 /// Mapping of rules (CFI states) that define the location of each 2524 /// register. If absent, no rule defining the location of such register 2525 /// was ever read. This number will be negative if it refers to a CFI 2526 /// located in the CIE instead of the FDE. 2527 DenseMap<int32_t, int32_t> RegRule; 2528 2529 /// References to CIE, FDE and expanded instructions after a restore state 2530 const BinaryFunction::CFIInstrMapType &CIE; 2531 const BinaryFunction::CFIInstrMapType &FDE; 2532 const DenseMap<int32_t, SmallVector<int32_t, 4>> &FrameRestoreEquivalents; 2533 2534 /// Current FDE CFI number representing the state where the snapshot is at 2535 int32_t CurState; 2536 2537 /// Used when we don't have information about which state/rule to apply 2538 /// to recover the location of either the CFA or a specific register 2539 constexpr static int32_t UNKNOWN = std::numeric_limits<int32_t>::min(); 2540 2541 private: 2542 /// Update our snapshot by executing a single CFI 2543 void update(const MCCFIInstruction &Instr, int32_t RuleNumber) { 2544 switch (Instr.getOperation()) { 2545 case MCCFIInstruction::OpSameValue: 2546 case MCCFIInstruction::OpRelOffset: 2547 case MCCFIInstruction::OpOffset: 2548 case MCCFIInstruction::OpRestore: 2549 case MCCFIInstruction::OpUndefined: 2550 case MCCFIInstruction::OpRegister: 2551 RegRule[Instr.getRegister()] = RuleNumber; 2552 break; 2553 case MCCFIInstruction::OpDefCfaRegister: 2554 CFAReg = Instr.getRegister(); 2555 CFARule = UNKNOWN; 2556 2557 // This shouldn't happen according to the spec but GNU binutils on RISC-V 2558 // emits a DW_CFA_def_cfa_register in CIE's which leaves the offset 2559 // unspecified. Both readelf and llvm-dwarfdump interpret the offset as 0 2560 // in this case so let's do the same. 2561 if (CFAOffset == UNKNOWN) 2562 CFAOffset = 0; 2563 break; 2564 case MCCFIInstruction::OpDefCfaOffset: 2565 CFAOffset = Instr.getOffset(); 2566 CFARule = UNKNOWN; 2567 break; 2568 case MCCFIInstruction::OpDefCfa: 2569 CFAReg = Instr.getRegister(); 2570 CFAOffset = Instr.getOffset(); 2571 CFARule = UNKNOWN; 2572 break; 2573 case MCCFIInstruction::OpEscape: { 2574 std::optional<uint8_t> Reg = 2575 readDWARFExpressionTargetReg(Instr.getValues()); 2576 // Handle DW_CFA_def_cfa_expression 2577 if (!Reg) { 2578 CFARule = RuleNumber; 2579 break; 2580 } 2581 RegRule[*Reg] = RuleNumber; 2582 break; 2583 } 2584 case MCCFIInstruction::OpAdjustCfaOffset: 2585 case MCCFIInstruction::OpWindowSave: 2586 case MCCFIInstruction::OpNegateRAState: 2587 case MCCFIInstruction::OpNegateRAStateWithPC: 2588 case MCCFIInstruction::OpLLVMDefAspaceCfa: 2589 case MCCFIInstruction::OpLabel: 2590 case MCCFIInstruction::OpValOffset: 2591 llvm_unreachable("unsupported CFI opcode"); 2592 break; 2593 case MCCFIInstruction::OpRememberState: 2594 case MCCFIInstruction::OpRestoreState: 2595 case MCCFIInstruction::OpGnuArgsSize: 2596 // do not affect CFI state 2597 break; 2598 } 2599 } 2600 2601 public: 2602 /// Advance state reading FDE CFI instructions up to State number 2603 void advanceTo(int32_t State) { 2604 for (int32_t I = CurState, E = State; I != E; ++I) { 2605 const MCCFIInstruction &Instr = FDE[I]; 2606 if (Instr.getOperation() != MCCFIInstruction::OpRestoreState) { 2607 update(Instr, I); 2608 continue; 2609 } 2610 // If restore state instruction, fetch the equivalent CFIs that have 2611 // the same effect of this restore. This is used to ensure remember- 2612 // restore pairs are completely removed. 2613 auto Iter = FrameRestoreEquivalents.find(I); 2614 if (Iter == FrameRestoreEquivalents.end()) 2615 continue; 2616 for (int32_t RuleNumber : Iter->second) 2617 update(FDE[RuleNumber], RuleNumber); 2618 } 2619 2620 assert(((CFAReg != (uint32_t)UNKNOWN && CFAOffset != UNKNOWN) || 2621 CFARule != UNKNOWN) && 2622 "CIE did not define default CFA?"); 2623 2624 CurState = State; 2625 } 2626 2627 /// Interpret all CIE and FDE instructions up until CFI State number and 2628 /// populate this snapshot 2629 CFISnapshot( 2630 const BinaryFunction::CFIInstrMapType &CIE, 2631 const BinaryFunction::CFIInstrMapType &FDE, 2632 const DenseMap<int32_t, SmallVector<int32_t, 4>> &FrameRestoreEquivalents, 2633 int32_t State) 2634 : CIE(CIE), FDE(FDE), FrameRestoreEquivalents(FrameRestoreEquivalents) { 2635 CFAReg = UNKNOWN; 2636 CFAOffset = UNKNOWN; 2637 CFARule = UNKNOWN; 2638 CurState = 0; 2639 2640 for (int32_t I = 0, E = CIE.size(); I != E; ++I) { 2641 const MCCFIInstruction &Instr = CIE[I]; 2642 update(Instr, -I); 2643 } 2644 2645 advanceTo(State); 2646 } 2647 }; 2648 2649 /// A CFI snapshot with the capability of checking if incremental additions to 2650 /// it are redundant. This is used to ensure we do not emit two CFI instructions 2651 /// back-to-back that are doing the same state change, or to avoid emitting a 2652 /// CFI at all when the state at that point would not be modified after that CFI 2653 struct CFISnapshotDiff : public CFISnapshot { 2654 bool RestoredCFAReg{false}; 2655 bool RestoredCFAOffset{false}; 2656 DenseMap<int32_t, bool> RestoredRegs; 2657 2658 CFISnapshotDiff(const CFISnapshot &S) : CFISnapshot(S) {} 2659 2660 CFISnapshotDiff( 2661 const BinaryFunction::CFIInstrMapType &CIE, 2662 const BinaryFunction::CFIInstrMapType &FDE, 2663 const DenseMap<int32_t, SmallVector<int32_t, 4>> &FrameRestoreEquivalents, 2664 int32_t State) 2665 : CFISnapshot(CIE, FDE, FrameRestoreEquivalents, State) {} 2666 2667 /// Return true if applying Instr to this state is redundant and can be 2668 /// dismissed. 2669 bool isRedundant(const MCCFIInstruction &Instr) { 2670 switch (Instr.getOperation()) { 2671 case MCCFIInstruction::OpSameValue: 2672 case MCCFIInstruction::OpRelOffset: 2673 case MCCFIInstruction::OpOffset: 2674 case MCCFIInstruction::OpRestore: 2675 case MCCFIInstruction::OpUndefined: 2676 case MCCFIInstruction::OpRegister: 2677 case MCCFIInstruction::OpEscape: { 2678 uint32_t Reg; 2679 if (Instr.getOperation() != MCCFIInstruction::OpEscape) { 2680 Reg = Instr.getRegister(); 2681 } else { 2682 std::optional<uint8_t> R = 2683 readDWARFExpressionTargetReg(Instr.getValues()); 2684 // Handle DW_CFA_def_cfa_expression 2685 if (!R) { 2686 if (RestoredCFAReg && RestoredCFAOffset) 2687 return true; 2688 RestoredCFAReg = true; 2689 RestoredCFAOffset = true; 2690 return false; 2691 } 2692 Reg = *R; 2693 } 2694 if (RestoredRegs[Reg]) 2695 return true; 2696 RestoredRegs[Reg] = true; 2697 const int32_t CurRegRule = RegRule.contains(Reg) ? RegRule[Reg] : UNKNOWN; 2698 if (CurRegRule == UNKNOWN) { 2699 if (Instr.getOperation() == MCCFIInstruction::OpRestore || 2700 Instr.getOperation() == MCCFIInstruction::OpSameValue) 2701 return true; 2702 return false; 2703 } 2704 const MCCFIInstruction &LastDef = 2705 CurRegRule < 0 ? CIE[-CurRegRule] : FDE[CurRegRule]; 2706 return LastDef == Instr; 2707 } 2708 case MCCFIInstruction::OpDefCfaRegister: 2709 if (RestoredCFAReg) 2710 return true; 2711 RestoredCFAReg = true; 2712 return CFAReg == Instr.getRegister(); 2713 case MCCFIInstruction::OpDefCfaOffset: 2714 if (RestoredCFAOffset) 2715 return true; 2716 RestoredCFAOffset = true; 2717 return CFAOffset == Instr.getOffset(); 2718 case MCCFIInstruction::OpDefCfa: 2719 if (RestoredCFAReg && RestoredCFAOffset) 2720 return true; 2721 RestoredCFAReg = true; 2722 RestoredCFAOffset = true; 2723 return CFAReg == Instr.getRegister() && CFAOffset == Instr.getOffset(); 2724 case MCCFIInstruction::OpAdjustCfaOffset: 2725 case MCCFIInstruction::OpWindowSave: 2726 case MCCFIInstruction::OpNegateRAState: 2727 case MCCFIInstruction::OpNegateRAStateWithPC: 2728 case MCCFIInstruction::OpLLVMDefAspaceCfa: 2729 case MCCFIInstruction::OpLabel: 2730 case MCCFIInstruction::OpValOffset: 2731 llvm_unreachable("unsupported CFI opcode"); 2732 return false; 2733 case MCCFIInstruction::OpRememberState: 2734 case MCCFIInstruction::OpRestoreState: 2735 case MCCFIInstruction::OpGnuArgsSize: 2736 // do not affect CFI state 2737 return true; 2738 } 2739 return false; 2740 } 2741 }; 2742 2743 } // end anonymous namespace 2744 2745 bool BinaryFunction::replayCFIInstrs(int32_t FromState, int32_t ToState, 2746 BinaryBasicBlock *InBB, 2747 BinaryBasicBlock::iterator InsertIt) { 2748 if (FromState == ToState) 2749 return true; 2750 assert(FromState < ToState && "can only replay CFIs forward"); 2751 2752 CFISnapshotDiff CFIDiff(CIEFrameInstructions, FrameInstructions, 2753 FrameRestoreEquivalents, FromState); 2754 2755 std::vector<uint32_t> NewCFIs; 2756 for (int32_t CurState = FromState; CurState < ToState; ++CurState) { 2757 MCCFIInstruction *Instr = &FrameInstructions[CurState]; 2758 if (Instr->getOperation() == MCCFIInstruction::OpRestoreState) { 2759 auto Iter = FrameRestoreEquivalents.find(CurState); 2760 assert(Iter != FrameRestoreEquivalents.end()); 2761 NewCFIs.insert(NewCFIs.end(), Iter->second.begin(), Iter->second.end()); 2762 // RestoreState / Remember will be filtered out later by CFISnapshotDiff, 2763 // so we might as well fall-through here. 2764 } 2765 NewCFIs.push_back(CurState); 2766 } 2767 2768 // Replay instructions while avoiding duplicates 2769 for (int32_t State : llvm::reverse(NewCFIs)) { 2770 if (CFIDiff.isRedundant(FrameInstructions[State])) 2771 continue; 2772 InsertIt = addCFIPseudo(InBB, InsertIt, State); 2773 } 2774 2775 return true; 2776 } 2777 2778 SmallVector<int32_t, 4> 2779 BinaryFunction::unwindCFIState(int32_t FromState, int32_t ToState, 2780 BinaryBasicBlock *InBB, 2781 BinaryBasicBlock::iterator &InsertIt) { 2782 SmallVector<int32_t, 4> NewStates; 2783 2784 CFISnapshot ToCFITable(CIEFrameInstructions, FrameInstructions, 2785 FrameRestoreEquivalents, ToState); 2786 CFISnapshotDiff FromCFITable(ToCFITable); 2787 FromCFITable.advanceTo(FromState); 2788 2789 auto undoStateDefCfa = [&]() { 2790 if (ToCFITable.CFARule == CFISnapshot::UNKNOWN) { 2791 FrameInstructions.emplace_back(MCCFIInstruction::cfiDefCfa( 2792 nullptr, ToCFITable.CFAReg, ToCFITable.CFAOffset)); 2793 if (FromCFITable.isRedundant(FrameInstructions.back())) { 2794 FrameInstructions.pop_back(); 2795 return; 2796 } 2797 NewStates.push_back(FrameInstructions.size() - 1); 2798 InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size() - 1); 2799 ++InsertIt; 2800 } else if (ToCFITable.CFARule < 0) { 2801 if (FromCFITable.isRedundant(CIEFrameInstructions[-ToCFITable.CFARule])) 2802 return; 2803 NewStates.push_back(FrameInstructions.size()); 2804 InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size()); 2805 ++InsertIt; 2806 FrameInstructions.emplace_back(CIEFrameInstructions[-ToCFITable.CFARule]); 2807 } else if (!FromCFITable.isRedundant( 2808 FrameInstructions[ToCFITable.CFARule])) { 2809 NewStates.push_back(ToCFITable.CFARule); 2810 InsertIt = addCFIPseudo(InBB, InsertIt, ToCFITable.CFARule); 2811 ++InsertIt; 2812 } 2813 }; 2814 2815 auto undoState = [&](const MCCFIInstruction &Instr) { 2816 switch (Instr.getOperation()) { 2817 case MCCFIInstruction::OpRememberState: 2818 case MCCFIInstruction::OpRestoreState: 2819 break; 2820 case MCCFIInstruction::OpSameValue: 2821 case MCCFIInstruction::OpRelOffset: 2822 case MCCFIInstruction::OpOffset: 2823 case MCCFIInstruction::OpRestore: 2824 case MCCFIInstruction::OpUndefined: 2825 case MCCFIInstruction::OpEscape: 2826 case MCCFIInstruction::OpRegister: { 2827 uint32_t Reg; 2828 if (Instr.getOperation() != MCCFIInstruction::OpEscape) { 2829 Reg = Instr.getRegister(); 2830 } else { 2831 std::optional<uint8_t> R = 2832 readDWARFExpressionTargetReg(Instr.getValues()); 2833 // Handle DW_CFA_def_cfa_expression 2834 if (!R) { 2835 undoStateDefCfa(); 2836 return; 2837 } 2838 Reg = *R; 2839 } 2840 2841 if (!ToCFITable.RegRule.contains(Reg)) { 2842 FrameInstructions.emplace_back( 2843 MCCFIInstruction::createRestore(nullptr, Reg)); 2844 if (FromCFITable.isRedundant(FrameInstructions.back())) { 2845 FrameInstructions.pop_back(); 2846 break; 2847 } 2848 NewStates.push_back(FrameInstructions.size() - 1); 2849 InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size() - 1); 2850 ++InsertIt; 2851 break; 2852 } 2853 const int32_t Rule = ToCFITable.RegRule[Reg]; 2854 if (Rule < 0) { 2855 if (FromCFITable.isRedundant(CIEFrameInstructions[-Rule])) 2856 break; 2857 NewStates.push_back(FrameInstructions.size()); 2858 InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size()); 2859 ++InsertIt; 2860 FrameInstructions.emplace_back(CIEFrameInstructions[-Rule]); 2861 break; 2862 } 2863 if (FromCFITable.isRedundant(FrameInstructions[Rule])) 2864 break; 2865 NewStates.push_back(Rule); 2866 InsertIt = addCFIPseudo(InBB, InsertIt, Rule); 2867 ++InsertIt; 2868 break; 2869 } 2870 case MCCFIInstruction::OpDefCfaRegister: 2871 case MCCFIInstruction::OpDefCfaOffset: 2872 case MCCFIInstruction::OpDefCfa: 2873 undoStateDefCfa(); 2874 break; 2875 case MCCFIInstruction::OpAdjustCfaOffset: 2876 case MCCFIInstruction::OpWindowSave: 2877 case MCCFIInstruction::OpNegateRAState: 2878 case MCCFIInstruction::OpNegateRAStateWithPC: 2879 case MCCFIInstruction::OpLLVMDefAspaceCfa: 2880 case MCCFIInstruction::OpLabel: 2881 case MCCFIInstruction::OpValOffset: 2882 llvm_unreachable("unsupported CFI opcode"); 2883 break; 2884 case MCCFIInstruction::OpGnuArgsSize: 2885 // do not affect CFI state 2886 break; 2887 } 2888 }; 2889 2890 // Undo all modifications from ToState to FromState 2891 for (int32_t I = ToState, E = FromState; I != E; ++I) { 2892 const MCCFIInstruction &Instr = FrameInstructions[I]; 2893 if (Instr.getOperation() != MCCFIInstruction::OpRestoreState) { 2894 undoState(Instr); 2895 continue; 2896 } 2897 auto Iter = FrameRestoreEquivalents.find(I); 2898 if (Iter == FrameRestoreEquivalents.end()) 2899 continue; 2900 for (int32_t State : Iter->second) 2901 undoState(FrameInstructions[State]); 2902 } 2903 2904 return NewStates; 2905 } 2906 2907 void BinaryFunction::normalizeCFIState() { 2908 // Reordering blocks with remember-restore state instructions can be specially 2909 // tricky. When rewriting the CFI, we omit remember-restore state instructions 2910 // entirely. For restore state, we build a map expanding each restore to the 2911 // equivalent unwindCFIState sequence required at that point to achieve the 2912 // same effect of the restore. All remember state are then just ignored. 2913 std::stack<int32_t> Stack; 2914 for (BinaryBasicBlock *CurBB : Layout.blocks()) { 2915 for (auto II = CurBB->begin(); II != CurBB->end(); ++II) { 2916 if (const MCCFIInstruction *CFI = getCFIFor(*II)) { 2917 if (CFI->getOperation() == MCCFIInstruction::OpRememberState) { 2918 Stack.push(II->getOperand(0).getImm()); 2919 continue; 2920 } 2921 if (CFI->getOperation() == MCCFIInstruction::OpRestoreState) { 2922 const int32_t RememberState = Stack.top(); 2923 const int32_t CurState = II->getOperand(0).getImm(); 2924 FrameRestoreEquivalents[CurState] = 2925 unwindCFIState(CurState, RememberState, CurBB, II); 2926 Stack.pop(); 2927 } 2928 } 2929 } 2930 } 2931 } 2932 2933 bool BinaryFunction::finalizeCFIState() { 2934 LLVM_DEBUG( 2935 dbgs() << "Trying to fix CFI states for each BB after reordering.\n"); 2936 LLVM_DEBUG(dbgs() << "This is the list of CFI states for each BB of " << *this 2937 << ": "); 2938 2939 const char *Sep = ""; 2940 (void)Sep; 2941 for (FunctionFragment &FF : Layout.fragments()) { 2942 // Hot-cold border: at start of each region (with a different FDE) we need 2943 // to reset the CFI state. 2944 int32_t State = 0; 2945 2946 for (BinaryBasicBlock *BB : FF) { 2947 const int32_t CFIStateAtExit = BB->getCFIStateAtExit(); 2948 2949 // We need to recover the correct state if it doesn't match expected 2950 // state at BB entry point. 2951 if (BB->getCFIState() < State) { 2952 // In this case, State is currently higher than what this BB expect it 2953 // to be. To solve this, we need to insert CFI instructions to undo 2954 // the effect of all CFI from BB's state to current State. 2955 auto InsertIt = BB->begin(); 2956 unwindCFIState(State, BB->getCFIState(), BB, InsertIt); 2957 } else if (BB->getCFIState() > State) { 2958 // If BB's CFI state is greater than State, it means we are behind in 2959 // the state. Just emit all instructions to reach this state at the 2960 // beginning of this BB. If this sequence of instructions involve 2961 // remember state or restore state, bail out. 2962 if (!replayCFIInstrs(State, BB->getCFIState(), BB, BB->begin())) 2963 return false; 2964 } 2965 2966 State = CFIStateAtExit; 2967 LLVM_DEBUG(dbgs() << Sep << State; Sep = ", "); 2968 } 2969 } 2970 LLVM_DEBUG(dbgs() << "\n"); 2971 2972 for (BinaryBasicBlock &BB : blocks()) { 2973 for (auto II = BB.begin(); II != BB.end();) { 2974 const MCCFIInstruction *CFI = getCFIFor(*II); 2975 if (CFI && (CFI->getOperation() == MCCFIInstruction::OpRememberState || 2976 CFI->getOperation() == MCCFIInstruction::OpRestoreState)) { 2977 II = BB.eraseInstruction(II); 2978 } else { 2979 ++II; 2980 } 2981 } 2982 } 2983 2984 return true; 2985 } 2986 2987 bool BinaryFunction::requiresAddressTranslation() const { 2988 return opts::EnableBAT || hasSDTMarker() || hasPseudoProbe(); 2989 } 2990 2991 bool BinaryFunction::requiresAddressMap() const { 2992 if (isInjected()) 2993 return false; 2994 2995 return opts::UpdateDebugSections || isMultiEntry() || 2996 requiresAddressTranslation(); 2997 } 2998 2999 uint64_t BinaryFunction::getInstructionCount() const { 3000 uint64_t Count = 0; 3001 for (const BinaryBasicBlock &BB : blocks()) 3002 Count += BB.getNumNonPseudos(); 3003 return Count; 3004 } 3005 3006 void BinaryFunction::clearDisasmState() { 3007 clearList(Instructions); 3008 clearList(IgnoredBranches); 3009 clearList(TakenBranches); 3010 3011 if (BC.HasRelocations) { 3012 for (std::pair<const uint32_t, MCSymbol *> &LI : Labels) 3013 BC.UndefinedSymbols.insert(LI.second); 3014 for (MCSymbol *const EndLabel : FunctionEndLabels) 3015 if (EndLabel) 3016 BC.UndefinedSymbols.insert(EndLabel); 3017 } 3018 } 3019 3020 void BinaryFunction::setTrapOnEntry() { 3021 clearDisasmState(); 3022 3023 forEachEntryPoint([&](uint64_t Offset, const MCSymbol *Label) -> bool { 3024 MCInst TrapInstr; 3025 BC.MIB->createTrap(TrapInstr); 3026 addInstruction(Offset, std::move(TrapInstr)); 3027 return true; 3028 }); 3029 3030 TrapsOnEntry = true; 3031 } 3032 3033 void BinaryFunction::setIgnored() { 3034 if (opts::processAllFunctions()) { 3035 // We can accept ignored functions before they've been disassembled. 3036 // In that case, they would still get disassembled and emited, but not 3037 // optimized. 3038 assert(CurrentState == State::Empty && 3039 "cannot ignore non-empty functions in current mode"); 3040 IsIgnored = true; 3041 return; 3042 } 3043 3044 clearDisasmState(); 3045 3046 // Clear CFG state too. 3047 if (hasCFG()) { 3048 releaseCFG(); 3049 3050 for (BinaryBasicBlock *BB : BasicBlocks) 3051 delete BB; 3052 clearList(BasicBlocks); 3053 3054 for (BinaryBasicBlock *BB : DeletedBasicBlocks) 3055 delete BB; 3056 clearList(DeletedBasicBlocks); 3057 3058 Layout.clear(); 3059 } 3060 3061 CurrentState = State::Empty; 3062 3063 IsIgnored = true; 3064 IsSimple = false; 3065 LLVM_DEBUG(dbgs() << "Ignoring " << getPrintName() << '\n'); 3066 } 3067 3068 void BinaryFunction::duplicateConstantIslands() { 3069 assert(Islands && "function expected to have constant islands"); 3070 3071 for (BinaryBasicBlock *BB : getLayout().blocks()) { 3072 if (!BB->isCold()) 3073 continue; 3074 3075 for (MCInst &Inst : *BB) { 3076 int OpNum = 0; 3077 for (MCOperand &Operand : Inst) { 3078 if (!Operand.isExpr()) { 3079 ++OpNum; 3080 continue; 3081 } 3082 const MCSymbol *Symbol = BC.MIB->getTargetSymbol(Inst, OpNum); 3083 // Check if this is an island symbol 3084 if (!Islands->Symbols.count(Symbol) && 3085 !Islands->ProxySymbols.count(Symbol)) 3086 continue; 3087 3088 // Create cold symbol, if missing 3089 auto ISym = Islands->ColdSymbols.find(Symbol); 3090 MCSymbol *ColdSymbol; 3091 if (ISym != Islands->ColdSymbols.end()) { 3092 ColdSymbol = ISym->second; 3093 } else { 3094 ColdSymbol = BC.Ctx->getOrCreateSymbol(Symbol->getName() + ".cold"); 3095 Islands->ColdSymbols[Symbol] = ColdSymbol; 3096 // Check if this is a proxy island symbol and update owner proxy map 3097 if (Islands->ProxySymbols.count(Symbol)) { 3098 BinaryFunction *Owner = Islands->ProxySymbols[Symbol]; 3099 auto IProxiedSym = Owner->Islands->Proxies[this].find(Symbol); 3100 Owner->Islands->ColdProxies[this][IProxiedSym->second] = ColdSymbol; 3101 } 3102 } 3103 3104 // Update instruction reference 3105 Operand = MCOperand::createExpr(BC.MIB->getTargetExprFor( 3106 Inst, 3107 MCSymbolRefExpr::create(ColdSymbol, MCSymbolRefExpr::VK_None, 3108 *BC.Ctx), 3109 *BC.Ctx, 0)); 3110 ++OpNum; 3111 } 3112 } 3113 } 3114 } 3115 3116 #ifndef MAX_PATH 3117 #define MAX_PATH 255 3118 #endif 3119 3120 static std::string constructFilename(std::string Filename, 3121 std::string Annotation, 3122 std::string Suffix) { 3123 std::replace(Filename.begin(), Filename.end(), '/', '-'); 3124 if (!Annotation.empty()) 3125 Annotation.insert(0, "-"); 3126 if (Filename.size() + Annotation.size() + Suffix.size() > MAX_PATH) { 3127 assert(Suffix.size() + Annotation.size() <= MAX_PATH); 3128 Filename.resize(MAX_PATH - (Suffix.size() + Annotation.size())); 3129 } 3130 Filename += Annotation; 3131 Filename += Suffix; 3132 return Filename; 3133 } 3134 3135 static std::string formatEscapes(const std::string &Str) { 3136 std::string Result; 3137 for (unsigned I = 0; I < Str.size(); ++I) { 3138 char C = Str[I]; 3139 switch (C) { 3140 case '\n': 3141 Result += " "; 3142 break; 3143 case '"': 3144 break; 3145 default: 3146 Result += C; 3147 break; 3148 } 3149 } 3150 return Result; 3151 } 3152 3153 void BinaryFunction::dumpGraph(raw_ostream &OS) const { 3154 OS << "digraph \"" << getPrintName() << "\" {\n" 3155 << "node [fontname=courier, shape=box, style=filled, colorscheme=brbg9]\n"; 3156 uint64_t Offset = Address; 3157 for (BinaryBasicBlock *BB : BasicBlocks) { 3158 auto LayoutPos = find(Layout.blocks(), BB); 3159 unsigned LayoutIndex = LayoutPos - Layout.block_begin(); 3160 const char *ColdStr = BB->isCold() ? " (cold)" : ""; 3161 std::vector<std::string> Attrs; 3162 // Bold box for entry points 3163 if (isEntryPoint(*BB)) 3164 Attrs.push_back("penwidth=2"); 3165 if (BLI && BLI->getLoopFor(BB)) { 3166 // Distinguish innermost loops 3167 const BinaryLoop *Loop = BLI->getLoopFor(BB); 3168 if (Loop->isInnermost()) 3169 Attrs.push_back("fillcolor=6"); 3170 else // some outer loop 3171 Attrs.push_back("fillcolor=4"); 3172 } else { // non-loopy code 3173 Attrs.push_back("fillcolor=5"); 3174 } 3175 ListSeparator LS; 3176 OS << "\"" << BB->getName() << "\" ["; 3177 for (StringRef Attr : Attrs) 3178 OS << LS << Attr; 3179 OS << "]\n"; 3180 OS << format("\"%s\" [label=\"%s%s\\n(C:%lu,O:%lu,I:%u,L:%u,CFI:%u)\\n", 3181 BB->getName().data(), BB->getName().data(), ColdStr, 3182 BB->getKnownExecutionCount(), BB->getOffset(), getIndex(BB), 3183 LayoutIndex, BB->getCFIState()); 3184 3185 if (opts::DotToolTipCode) { 3186 std::string Str; 3187 raw_string_ostream CS(Str); 3188 Offset = BC.printInstructions(CS, BB->begin(), BB->end(), Offset, this, 3189 /* PrintMCInst = */ false, 3190 /* PrintMemData = */ false, 3191 /* PrintRelocations = */ false, 3192 /* Endl = */ R"(\\l)"); 3193 OS << formatEscapes(CS.str()) << '\n'; 3194 } 3195 OS << "\"]\n"; 3196 3197 // analyzeBranch is just used to get the names of the branch 3198 // opcodes. 3199 const MCSymbol *TBB = nullptr; 3200 const MCSymbol *FBB = nullptr; 3201 MCInst *CondBranch = nullptr; 3202 MCInst *UncondBranch = nullptr; 3203 const bool Success = BB->analyzeBranch(TBB, FBB, CondBranch, UncondBranch); 3204 3205 const MCInst *LastInstr = BB->getLastNonPseudoInstr(); 3206 const bool IsJumpTable = LastInstr && BC.MIB->getJumpTable(*LastInstr); 3207 3208 auto BI = BB->branch_info_begin(); 3209 for (BinaryBasicBlock *Succ : BB->successors()) { 3210 std::string Branch; 3211 if (Success) { 3212 if (Succ == BB->getConditionalSuccessor(true)) { 3213 Branch = CondBranch ? std::string(BC.InstPrinter->getOpcodeName( 3214 CondBranch->getOpcode())) 3215 : "TB"; 3216 } else if (Succ == BB->getConditionalSuccessor(false)) { 3217 Branch = UncondBranch ? std::string(BC.InstPrinter->getOpcodeName( 3218 UncondBranch->getOpcode())) 3219 : "FB"; 3220 } else { 3221 Branch = "FT"; 3222 } 3223 } 3224 if (IsJumpTable) 3225 Branch = "JT"; 3226 OS << format("\"%s\" -> \"%s\" [label=\"%s", BB->getName().data(), 3227 Succ->getName().data(), Branch.c_str()); 3228 3229 if (BB->getExecutionCount() != COUNT_NO_PROFILE && 3230 BI->MispredictedCount != BinaryBasicBlock::COUNT_INFERRED) { 3231 OS << "\\n(C:" << BI->Count << ",M:" << BI->MispredictedCount << ")"; 3232 } else if (ExecutionCount != COUNT_NO_PROFILE && 3233 BI->Count != BinaryBasicBlock::COUNT_NO_PROFILE) { 3234 OS << "\\n(IC:" << BI->Count << ")"; 3235 } 3236 OS << "\"]\n"; 3237 3238 ++BI; 3239 } 3240 for (BinaryBasicBlock *LP : BB->landing_pads()) { 3241 OS << format("\"%s\" -> \"%s\" [constraint=false style=dashed]\n", 3242 BB->getName().data(), LP->getName().data()); 3243 } 3244 } 3245 OS << "}\n"; 3246 } 3247 3248 void BinaryFunction::viewGraph() const { 3249 SmallString<MAX_PATH> Filename; 3250 if (std::error_code EC = 3251 sys::fs::createTemporaryFile("bolt-cfg", "dot", Filename)) { 3252 BC.errs() << "BOLT-ERROR: " << EC.message() << ", unable to create " 3253 << " bolt-cfg-XXXXX.dot temporary file.\n"; 3254 return; 3255 } 3256 dumpGraphToFile(std::string(Filename)); 3257 if (DisplayGraph(Filename)) 3258 BC.errs() << "BOLT-ERROR: Can't display " << Filename 3259 << " with graphviz.\n"; 3260 if (std::error_code EC = sys::fs::remove(Filename)) { 3261 BC.errs() << "BOLT-WARNING: " << EC.message() << ", failed to remove " 3262 << Filename << "\n"; 3263 } 3264 } 3265 3266 void BinaryFunction::dumpGraphForPass(std::string Annotation) const { 3267 if (!opts::shouldPrint(*this)) 3268 return; 3269 3270 std::string Filename = constructFilename(getPrintName(), Annotation, ".dot"); 3271 if (opts::Verbosity >= 1) 3272 BC.outs() << "BOLT-INFO: dumping CFG to " << Filename << "\n"; 3273 dumpGraphToFile(Filename); 3274 } 3275 3276 void BinaryFunction::dumpGraphToFile(std::string Filename) const { 3277 std::error_code EC; 3278 raw_fd_ostream of(Filename, EC, sys::fs::OF_None); 3279 if (EC) { 3280 if (opts::Verbosity >= 1) { 3281 BC.errs() << "BOLT-WARNING: " << EC.message() << ", unable to open " 3282 << Filename << " for output.\n"; 3283 } 3284 return; 3285 } 3286 dumpGraph(of); 3287 } 3288 3289 bool BinaryFunction::validateCFG() const { 3290 // Skip the validation of CFG after it is finalized 3291 if (CurrentState == State::CFG_Finalized) 3292 return true; 3293 3294 for (BinaryBasicBlock *BB : BasicBlocks) 3295 if (!BB->validateSuccessorInvariants()) 3296 return false; 3297 3298 // Make sure all blocks in CFG are valid. 3299 auto validateBlock = [this](const BinaryBasicBlock *BB, StringRef Desc) { 3300 if (!BB->isValid()) { 3301 BC.errs() << "BOLT-ERROR: deleted " << Desc << " " << BB->getName() 3302 << " detected in:\n"; 3303 this->dump(); 3304 return false; 3305 } 3306 return true; 3307 }; 3308 for (const BinaryBasicBlock *BB : BasicBlocks) { 3309 if (!validateBlock(BB, "block")) 3310 return false; 3311 for (const BinaryBasicBlock *PredBB : BB->predecessors()) 3312 if (!validateBlock(PredBB, "predecessor")) 3313 return false; 3314 for (const BinaryBasicBlock *SuccBB : BB->successors()) 3315 if (!validateBlock(SuccBB, "successor")) 3316 return false; 3317 for (const BinaryBasicBlock *LP : BB->landing_pads()) 3318 if (!validateBlock(LP, "landing pad")) 3319 return false; 3320 for (const BinaryBasicBlock *Thrower : BB->throwers()) 3321 if (!validateBlock(Thrower, "thrower")) 3322 return false; 3323 } 3324 3325 for (const BinaryBasicBlock *BB : BasicBlocks) { 3326 std::unordered_set<const BinaryBasicBlock *> BBLandingPads; 3327 for (const BinaryBasicBlock *LP : BB->landing_pads()) { 3328 if (BBLandingPads.count(LP)) { 3329 BC.errs() << "BOLT-ERROR: duplicate landing pad detected in" 3330 << BB->getName() << " in function " << *this << '\n'; 3331 return false; 3332 } 3333 BBLandingPads.insert(LP); 3334 } 3335 3336 std::unordered_set<const BinaryBasicBlock *> BBThrowers; 3337 for (const BinaryBasicBlock *Thrower : BB->throwers()) { 3338 if (BBThrowers.count(Thrower)) { 3339 BC.errs() << "BOLT-ERROR: duplicate thrower detected in" 3340 << BB->getName() << " in function " << *this << '\n'; 3341 return false; 3342 } 3343 BBThrowers.insert(Thrower); 3344 } 3345 3346 for (const BinaryBasicBlock *LPBlock : BB->landing_pads()) { 3347 if (!llvm::is_contained(LPBlock->throwers(), BB)) { 3348 BC.errs() << "BOLT-ERROR: inconsistent landing pad detected in " 3349 << *this << ": " << BB->getName() 3350 << " is in LandingPads but not in " << LPBlock->getName() 3351 << " Throwers\n"; 3352 return false; 3353 } 3354 } 3355 for (const BinaryBasicBlock *Thrower : BB->throwers()) { 3356 if (!llvm::is_contained(Thrower->landing_pads(), BB)) { 3357 BC.errs() << "BOLT-ERROR: inconsistent thrower detected in " << *this 3358 << ": " << BB->getName() << " is in Throwers list but not in " 3359 << Thrower->getName() << " LandingPads\n"; 3360 return false; 3361 } 3362 } 3363 } 3364 3365 return true; 3366 } 3367 3368 void BinaryFunction::fixBranches() { 3369 auto &MIB = BC.MIB; 3370 MCContext *Ctx = BC.Ctx.get(); 3371 3372 for (BinaryBasicBlock *BB : BasicBlocks) { 3373 const MCSymbol *TBB = nullptr; 3374 const MCSymbol *FBB = nullptr; 3375 MCInst *CondBranch = nullptr; 3376 MCInst *UncondBranch = nullptr; 3377 if (!BB->analyzeBranch(TBB, FBB, CondBranch, UncondBranch)) 3378 continue; 3379 3380 // We will create unconditional branch with correct destination if needed. 3381 if (UncondBranch) 3382 BB->eraseInstruction(BB->findInstruction(UncondBranch)); 3383 3384 // Basic block that follows the current one in the final layout. 3385 const BinaryBasicBlock *const NextBB = 3386 Layout.getBasicBlockAfter(BB, /*IgnoreSplits=*/false); 3387 3388 if (BB->succ_size() == 1) { 3389 // __builtin_unreachable() could create a conditional branch that 3390 // falls-through into the next function - hence the block will have only 3391 // one valid successor. Since behaviour is undefined - we replace 3392 // the conditional branch with an unconditional if required. 3393 if (CondBranch) 3394 BB->eraseInstruction(BB->findInstruction(CondBranch)); 3395 if (BB->getSuccessor() == NextBB) 3396 continue; 3397 BB->addBranchInstruction(BB->getSuccessor()); 3398 } else if (BB->succ_size() == 2) { 3399 assert(CondBranch && "conditional branch expected"); 3400 const BinaryBasicBlock *TSuccessor = BB->getConditionalSuccessor(true); 3401 const BinaryBasicBlock *FSuccessor = BB->getConditionalSuccessor(false); 3402 3403 // Eliminate unnecessary conditional branch. 3404 if (TSuccessor == FSuccessor) { 3405 // FIXME: at the moment, we cannot safely remove static key branches. 3406 if (MIB->isDynamicBranch(*CondBranch)) { 3407 if (opts::Verbosity) { 3408 BC.outs() 3409 << "BOLT-INFO: unable to remove redundant dynamic branch in " 3410 << *this << '\n'; 3411 } 3412 continue; 3413 } 3414 3415 BB->removeDuplicateConditionalSuccessor(CondBranch); 3416 if (TSuccessor != NextBB) 3417 BB->addBranchInstruction(TSuccessor); 3418 continue; 3419 } 3420 3421 // Reverse branch condition and swap successors. 3422 auto swapSuccessors = [&]() { 3423 if (!MIB->isReversibleBranch(*CondBranch)) { 3424 if (opts::Verbosity) { 3425 BC.outs() << "BOLT-INFO: unable to swap successors in " << *this 3426 << '\n'; 3427 } 3428 return false; 3429 } 3430 std::swap(TSuccessor, FSuccessor); 3431 BB->swapConditionalSuccessors(); 3432 auto L = BC.scopeLock(); 3433 MIB->reverseBranchCondition(*CondBranch, TSuccessor->getLabel(), Ctx); 3434 return true; 3435 }; 3436 3437 // Check whether the next block is a "taken" target and try to swap it 3438 // with a "fall-through" target. 3439 if (TSuccessor == NextBB && swapSuccessors()) 3440 continue; 3441 3442 // Update conditional branch destination if needed. 3443 if (MIB->getTargetSymbol(*CondBranch) != TSuccessor->getLabel()) { 3444 auto L = BC.scopeLock(); 3445 MIB->replaceBranchTarget(*CondBranch, TSuccessor->getLabel(), Ctx); 3446 } 3447 3448 // No need for the unconditional branch. 3449 if (FSuccessor == NextBB) 3450 continue; 3451 3452 if (BC.isX86()) { 3453 // We are going to generate two branches. Check if their targets are in 3454 // the same fragment as this block. If only one target is in the same 3455 // fragment, make it the destination of the conditional branch. There 3456 // is a chance it will be a short branch which takes 4 bytes fewer than 3457 // a long conditional branch. For unconditional branch, the difference 3458 // is 3 bytes. 3459 if (BB->getFragmentNum() != TSuccessor->getFragmentNum() && 3460 BB->getFragmentNum() == FSuccessor->getFragmentNum()) 3461 swapSuccessors(); 3462 } 3463 3464 BB->addBranchInstruction(FSuccessor); 3465 } 3466 // Cases where the number of successors is 0 (block ends with a 3467 // terminator) or more than 2 (switch table) don't require branch 3468 // instruction adjustments. 3469 } 3470 assert((!isSimple() || validateCFG()) && 3471 "Invalid CFG detected after fixing branches"); 3472 } 3473 3474 void BinaryFunction::propagateGnuArgsSizeInfo( 3475 MCPlusBuilder::AllocatorIdTy AllocId) { 3476 assert(CurrentState == State::Disassembled && "unexpected function state"); 3477 3478 if (!hasEHRanges() || !usesGnuArgsSize()) 3479 return; 3480 3481 // The current value of DW_CFA_GNU_args_size affects all following 3482 // invoke instructions until the next CFI overrides it. 3483 // It is important to iterate basic blocks in the original order when 3484 // assigning the value. 3485 uint64_t CurrentGnuArgsSize = 0; 3486 for (BinaryBasicBlock *BB : BasicBlocks) { 3487 for (auto II = BB->begin(); II != BB->end();) { 3488 MCInst &Instr = *II; 3489 if (BC.MIB->isCFI(Instr)) { 3490 const MCCFIInstruction *CFI = getCFIFor(Instr); 3491 if (CFI->getOperation() == MCCFIInstruction::OpGnuArgsSize) { 3492 CurrentGnuArgsSize = CFI->getOffset(); 3493 // Delete DW_CFA_GNU_args_size instructions and only regenerate 3494 // during the final code emission. The information is embedded 3495 // inside call instructions. 3496 II = BB->erasePseudoInstruction(II); 3497 continue; 3498 } 3499 } else if (BC.MIB->isInvoke(Instr)) { 3500 // Add the value of GNU_args_size as an extra operand to invokes. 3501 BC.MIB->addGnuArgsSize(Instr, CurrentGnuArgsSize); 3502 } 3503 ++II; 3504 } 3505 } 3506 } 3507 3508 void BinaryFunction::postProcessBranches() { 3509 if (!isSimple()) 3510 return; 3511 for (BinaryBasicBlock &BB : blocks()) { 3512 auto LastInstrRI = BB.getLastNonPseudo(); 3513 if (BB.succ_size() == 1) { 3514 if (LastInstrRI != BB.rend() && 3515 BC.MIB->isConditionalBranch(*LastInstrRI)) { 3516 // __builtin_unreachable() could create a conditional branch that 3517 // falls-through into the next function - hence the block will have only 3518 // one valid successor. Such behaviour is undefined and thus we remove 3519 // the conditional branch while leaving a valid successor. 3520 BB.eraseInstruction(std::prev(LastInstrRI.base())); 3521 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: erasing conditional branch in " 3522 << BB.getName() << " in function " << *this << '\n'); 3523 } 3524 } else if (BB.succ_size() == 0) { 3525 // Ignore unreachable basic blocks. 3526 if (BB.pred_size() == 0 || BB.isLandingPad()) 3527 continue; 3528 3529 // If it's the basic block that does not end up with a terminator - we 3530 // insert a return instruction unless it's a call instruction. 3531 if (LastInstrRI == BB.rend()) { 3532 LLVM_DEBUG( 3533 dbgs() << "BOLT-DEBUG: at least one instruction expected in BB " 3534 << BB.getName() << " in function " << *this << '\n'); 3535 continue; 3536 } 3537 if (!BC.MIB->isTerminator(*LastInstrRI) && 3538 !BC.MIB->isCall(*LastInstrRI)) { 3539 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: adding return to basic block " 3540 << BB.getName() << " in function " << *this << '\n'); 3541 MCInst ReturnInstr; 3542 BC.MIB->createReturn(ReturnInstr); 3543 BB.addInstruction(ReturnInstr); 3544 } 3545 } 3546 } 3547 assert(validateCFG() && "invalid CFG"); 3548 } 3549 3550 MCSymbol *BinaryFunction::addEntryPointAtOffset(uint64_t Offset) { 3551 assert(Offset && "cannot add primary entry point"); 3552 assert(CurrentState == State::Empty || CurrentState == State::Disassembled); 3553 3554 const uint64_t EntryPointAddress = getAddress() + Offset; 3555 MCSymbol *LocalSymbol = getOrCreateLocalLabel(EntryPointAddress); 3556 3557 MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(LocalSymbol); 3558 if (EntrySymbol) 3559 return EntrySymbol; 3560 3561 if (BinaryData *EntryBD = BC.getBinaryDataAtAddress(EntryPointAddress)) { 3562 EntrySymbol = EntryBD->getSymbol(); 3563 } else { 3564 EntrySymbol = BC.getOrCreateGlobalSymbol( 3565 EntryPointAddress, Twine("__ENTRY_") + getOneName() + "@"); 3566 } 3567 SecondaryEntryPoints[LocalSymbol] = EntrySymbol; 3568 3569 BC.setSymbolToFunctionMap(EntrySymbol, this); 3570 3571 return EntrySymbol; 3572 } 3573 3574 MCSymbol *BinaryFunction::addEntryPoint(const BinaryBasicBlock &BB) { 3575 assert(CurrentState == State::CFG && 3576 "basic block can be added as an entry only in a function with CFG"); 3577 3578 if (&BB == BasicBlocks.front()) 3579 return getSymbol(); 3580 3581 MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(BB); 3582 if (EntrySymbol) 3583 return EntrySymbol; 3584 3585 EntrySymbol = 3586 BC.Ctx->getOrCreateSymbol("__ENTRY_" + BB.getLabel()->getName()); 3587 3588 SecondaryEntryPoints[BB.getLabel()] = EntrySymbol; 3589 3590 BC.setSymbolToFunctionMap(EntrySymbol, this); 3591 3592 return EntrySymbol; 3593 } 3594 3595 MCSymbol *BinaryFunction::getSymbolForEntryID(uint64_t EntryID) { 3596 if (EntryID == 0) 3597 return getSymbol(); 3598 3599 if (!isMultiEntry()) 3600 return nullptr; 3601 3602 uint64_t NumEntries = 1; 3603 if (hasCFG()) { 3604 for (BinaryBasicBlock *BB : BasicBlocks) { 3605 MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(*BB); 3606 if (!EntrySymbol) 3607 continue; 3608 if (NumEntries == EntryID) 3609 return EntrySymbol; 3610 ++NumEntries; 3611 } 3612 } else { 3613 for (std::pair<const uint32_t, MCSymbol *> &KV : Labels) { 3614 MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(KV.second); 3615 if (!EntrySymbol) 3616 continue; 3617 if (NumEntries == EntryID) 3618 return EntrySymbol; 3619 ++NumEntries; 3620 } 3621 } 3622 3623 return nullptr; 3624 } 3625 3626 uint64_t BinaryFunction::getEntryIDForSymbol(const MCSymbol *Symbol) const { 3627 if (!isMultiEntry()) 3628 return 0; 3629 3630 for (const MCSymbol *FunctionSymbol : getSymbols()) 3631 if (FunctionSymbol == Symbol) 3632 return 0; 3633 3634 // Check all secondary entries available as either basic blocks or lables. 3635 uint64_t NumEntries = 1; 3636 for (const BinaryBasicBlock *BB : BasicBlocks) { 3637 MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(*BB); 3638 if (!EntrySymbol) 3639 continue; 3640 if (EntrySymbol == Symbol) 3641 return NumEntries; 3642 ++NumEntries; 3643 } 3644 NumEntries = 1; 3645 for (const std::pair<const uint32_t, MCSymbol *> &KV : Labels) { 3646 MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(KV.second); 3647 if (!EntrySymbol) 3648 continue; 3649 if (EntrySymbol == Symbol) 3650 return NumEntries; 3651 ++NumEntries; 3652 } 3653 3654 llvm_unreachable("symbol not found"); 3655 } 3656 3657 bool BinaryFunction::forEachEntryPoint(EntryPointCallbackTy Callback) const { 3658 bool Status = Callback(0, getSymbol()); 3659 if (!isMultiEntry()) 3660 return Status; 3661 3662 for (const std::pair<const uint32_t, MCSymbol *> &KV : Labels) { 3663 if (!Status) 3664 break; 3665 3666 MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(KV.second); 3667 if (!EntrySymbol) 3668 continue; 3669 3670 Status = Callback(KV.first, EntrySymbol); 3671 } 3672 3673 return Status; 3674 } 3675 3676 BinaryFunction::BasicBlockListType BinaryFunction::dfs() const { 3677 BasicBlockListType DFS; 3678 std::stack<BinaryBasicBlock *> Stack; 3679 std::set<BinaryBasicBlock *> Visited; 3680 3681 // Push entry points to the stack in reverse order. 3682 // 3683 // NB: we rely on the original order of entries to match. 3684 SmallVector<BinaryBasicBlock *> EntryPoints; 3685 llvm::copy_if(BasicBlocks, std::back_inserter(EntryPoints), 3686 [&](const BinaryBasicBlock *const BB) { return isEntryPoint(*BB); }); 3687 // Sort entry points by their offset to make sure we got them in the right 3688 // order. 3689 llvm::stable_sort(EntryPoints, [](const BinaryBasicBlock *const A, 3690 const BinaryBasicBlock *const B) { 3691 return A->getOffset() < B->getOffset(); 3692 }); 3693 for (BinaryBasicBlock *const BB : reverse(EntryPoints)) 3694 Stack.push(BB); 3695 3696 while (!Stack.empty()) { 3697 BinaryBasicBlock *BB = Stack.top(); 3698 Stack.pop(); 3699 3700 if (!Visited.insert(BB).second) 3701 continue; 3702 DFS.push_back(BB); 3703 3704 for (BinaryBasicBlock *SuccBB : BB->landing_pads()) { 3705 Stack.push(SuccBB); 3706 } 3707 3708 const MCSymbol *TBB = nullptr; 3709 const MCSymbol *FBB = nullptr; 3710 MCInst *CondBranch = nullptr; 3711 MCInst *UncondBranch = nullptr; 3712 if (BB->analyzeBranch(TBB, FBB, CondBranch, UncondBranch) && CondBranch && 3713 BB->succ_size() == 2) { 3714 if (BC.MIB->getCanonicalBranchCondCode(BC.MIB->getCondCode( 3715 *CondBranch)) == BC.MIB->getCondCode(*CondBranch)) { 3716 Stack.push(BB->getConditionalSuccessor(true)); 3717 Stack.push(BB->getConditionalSuccessor(false)); 3718 } else { 3719 Stack.push(BB->getConditionalSuccessor(false)); 3720 Stack.push(BB->getConditionalSuccessor(true)); 3721 } 3722 } else { 3723 for (BinaryBasicBlock *SuccBB : BB->successors()) { 3724 Stack.push(SuccBB); 3725 } 3726 } 3727 } 3728 3729 return DFS; 3730 } 3731 3732 size_t BinaryFunction::computeHash(bool UseDFS, HashFunction HashFunction, 3733 OperandHashFuncTy OperandHashFunc) const { 3734 LLVM_DEBUG({ 3735 dbgs() << "BOLT-DEBUG: computeHash " << getPrintName() << ' ' 3736 << (UseDFS ? "dfs" : "bin") << " order " 3737 << (HashFunction == HashFunction::StdHash ? "std::hash" : "xxh3") 3738 << '\n'; 3739 }); 3740 3741 if (size() == 0) 3742 return 0; 3743 3744 assert(hasCFG() && "function is expected to have CFG"); 3745 3746 SmallVector<const BinaryBasicBlock *, 0> Order; 3747 if (UseDFS) 3748 llvm::copy(dfs(), std::back_inserter(Order)); 3749 else 3750 llvm::copy(Layout.blocks(), std::back_inserter(Order)); 3751 3752 // The hash is computed by creating a string of all instruction opcodes and 3753 // possibly their operands and then hashing that string with std::hash. 3754 std::string HashString; 3755 for (const BinaryBasicBlock *BB : Order) 3756 HashString.append(hashBlock(BC, *BB, OperandHashFunc)); 3757 3758 switch (HashFunction) { 3759 case HashFunction::StdHash: 3760 return Hash = std::hash<std::string>{}(HashString); 3761 case HashFunction::XXH3: 3762 return Hash = llvm::xxh3_64bits(HashString); 3763 } 3764 llvm_unreachable("Unhandled HashFunction"); 3765 } 3766 3767 void BinaryFunction::insertBasicBlocks( 3768 BinaryBasicBlock *Start, 3769 std::vector<std::unique_ptr<BinaryBasicBlock>> &&NewBBs, 3770 const bool UpdateLayout, const bool UpdateCFIState, 3771 const bool RecomputeLandingPads) { 3772 const int64_t StartIndex = Start ? getIndex(Start) : -1LL; 3773 const size_t NumNewBlocks = NewBBs.size(); 3774 3775 BasicBlocks.insert(BasicBlocks.begin() + (StartIndex + 1), NumNewBlocks, 3776 nullptr); 3777 3778 int64_t I = StartIndex + 1; 3779 for (std::unique_ptr<BinaryBasicBlock> &BB : NewBBs) { 3780 assert(!BasicBlocks[I]); 3781 BasicBlocks[I++] = BB.release(); 3782 } 3783 3784 if (RecomputeLandingPads) 3785 recomputeLandingPads(); 3786 else 3787 updateBBIndices(0); 3788 3789 if (UpdateLayout) 3790 updateLayout(Start, NumNewBlocks); 3791 3792 if (UpdateCFIState) 3793 updateCFIState(Start, NumNewBlocks); 3794 } 3795 3796 BinaryFunction::iterator BinaryFunction::insertBasicBlocks( 3797 BinaryFunction::iterator StartBB, 3798 std::vector<std::unique_ptr<BinaryBasicBlock>> &&NewBBs, 3799 const bool UpdateLayout, const bool UpdateCFIState, 3800 const bool RecomputeLandingPads) { 3801 const unsigned StartIndex = getIndex(&*StartBB); 3802 const size_t NumNewBlocks = NewBBs.size(); 3803 3804 BasicBlocks.insert(BasicBlocks.begin() + StartIndex + 1, NumNewBlocks, 3805 nullptr); 3806 auto RetIter = BasicBlocks.begin() + StartIndex + 1; 3807 3808 unsigned I = StartIndex + 1; 3809 for (std::unique_ptr<BinaryBasicBlock> &BB : NewBBs) { 3810 assert(!BasicBlocks[I]); 3811 BasicBlocks[I++] = BB.release(); 3812 } 3813 3814 if (RecomputeLandingPads) 3815 recomputeLandingPads(); 3816 else 3817 updateBBIndices(0); 3818 3819 if (UpdateLayout) 3820 updateLayout(*std::prev(RetIter), NumNewBlocks); 3821 3822 if (UpdateCFIState) 3823 updateCFIState(*std::prev(RetIter), NumNewBlocks); 3824 3825 return RetIter; 3826 } 3827 3828 void BinaryFunction::updateBBIndices(const unsigned StartIndex) { 3829 for (unsigned I = StartIndex; I < BasicBlocks.size(); ++I) 3830 BasicBlocks[I]->Index = I; 3831 } 3832 3833 void BinaryFunction::updateCFIState(BinaryBasicBlock *Start, 3834 const unsigned NumNewBlocks) { 3835 const int32_t CFIState = Start->getCFIStateAtExit(); 3836 const unsigned StartIndex = getIndex(Start) + 1; 3837 for (unsigned I = 0; I < NumNewBlocks; ++I) 3838 BasicBlocks[StartIndex + I]->setCFIState(CFIState); 3839 } 3840 3841 void BinaryFunction::updateLayout(BinaryBasicBlock *Start, 3842 const unsigned NumNewBlocks) { 3843 BasicBlockListType::iterator Begin; 3844 BasicBlockListType::iterator End; 3845 3846 // If start not provided copy new blocks from the beginning of BasicBlocks 3847 if (!Start) { 3848 Begin = BasicBlocks.begin(); 3849 End = BasicBlocks.begin() + NumNewBlocks; 3850 } else { 3851 unsigned StartIndex = getIndex(Start); 3852 Begin = std::next(BasicBlocks.begin(), StartIndex + 1); 3853 End = std::next(BasicBlocks.begin(), StartIndex + NumNewBlocks + 1); 3854 } 3855 3856 // Insert new blocks in the layout immediately after Start. 3857 Layout.insertBasicBlocks(Start, {Begin, End}); 3858 Layout.updateLayoutIndices(); 3859 } 3860 3861 bool BinaryFunction::checkForAmbiguousJumpTables() { 3862 SmallSet<uint64_t, 4> JumpTables; 3863 for (BinaryBasicBlock *&BB : BasicBlocks) { 3864 for (MCInst &Inst : *BB) { 3865 if (!BC.MIB->isIndirectBranch(Inst)) 3866 continue; 3867 uint64_t JTAddress = BC.MIB->getJumpTable(Inst); 3868 if (!JTAddress) 3869 continue; 3870 // This address can be inside another jump table, but we only consider 3871 // it ambiguous when the same start address is used, not the same JT 3872 // object. 3873 if (!JumpTables.count(JTAddress)) { 3874 JumpTables.insert(JTAddress); 3875 continue; 3876 } 3877 return true; 3878 } 3879 } 3880 return false; 3881 } 3882 3883 void BinaryFunction::disambiguateJumpTables( 3884 MCPlusBuilder::AllocatorIdTy AllocId) { 3885 assert((opts::JumpTables != JTS_BASIC && isSimple()) || !BC.HasRelocations); 3886 SmallPtrSet<JumpTable *, 4> JumpTables; 3887 for (BinaryBasicBlock *&BB : BasicBlocks) { 3888 for (MCInst &Inst : *BB) { 3889 if (!BC.MIB->isIndirectBranch(Inst)) 3890 continue; 3891 JumpTable *JT = getJumpTable(Inst); 3892 if (!JT) 3893 continue; 3894 if (JumpTables.insert(JT).second) 3895 continue; 3896 // This instruction is an indirect jump using a jump table, but it is 3897 // using the same jump table of another jump. Try all our tricks to 3898 // extract the jump table symbol and make it point to a new, duplicated JT 3899 MCPhysReg BaseReg1; 3900 uint64_t Scale; 3901 const MCSymbol *Target; 3902 // In case we match if our first matcher, first instruction is the one to 3903 // patch 3904 MCInst *JTLoadInst = &Inst; 3905 // Try a standard indirect jump matcher, scale 8 3906 std::unique_ptr<MCPlusBuilder::MCInstMatcher> IndJmpMatcher = 3907 BC.MIB->matchIndJmp(BC.MIB->matchReg(BaseReg1), 3908 BC.MIB->matchImm(Scale), BC.MIB->matchReg(), 3909 /*Offset=*/BC.MIB->matchSymbol(Target)); 3910 if (!IndJmpMatcher->match( 3911 *BC.MRI, *BC.MIB, 3912 MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1) || 3913 BaseReg1 != BC.MIB->getNoRegister() || Scale != 8) { 3914 MCPhysReg BaseReg2; 3915 uint64_t Offset; 3916 // Standard JT matching failed. Trying now: 3917 // movq "jt.2397/1"(,%rax,8), %rax 3918 // jmpq *%rax 3919 std::unique_ptr<MCPlusBuilder::MCInstMatcher> LoadMatcherOwner = 3920 BC.MIB->matchLoad(BC.MIB->matchReg(BaseReg1), 3921 BC.MIB->matchImm(Scale), BC.MIB->matchReg(), 3922 /*Offset=*/BC.MIB->matchSymbol(Target)); 3923 MCPlusBuilder::MCInstMatcher *LoadMatcher = LoadMatcherOwner.get(); 3924 std::unique_ptr<MCPlusBuilder::MCInstMatcher> IndJmpMatcher2 = 3925 BC.MIB->matchIndJmp(std::move(LoadMatcherOwner)); 3926 if (!IndJmpMatcher2->match( 3927 *BC.MRI, *BC.MIB, 3928 MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1) || 3929 BaseReg1 != BC.MIB->getNoRegister() || Scale != 8) { 3930 // JT matching failed. Trying now: 3931 // PIC-style matcher, scale 4 3932 // addq %rdx, %rsi 3933 // addq %rdx, %rdi 3934 // leaq DATAat0x402450(%rip), %r11 3935 // movslq (%r11,%rdx,4), %rcx 3936 // addq %r11, %rcx 3937 // jmpq *%rcx # JUMPTABLE @0x402450 3938 std::unique_ptr<MCPlusBuilder::MCInstMatcher> PICIndJmpMatcher = 3939 BC.MIB->matchIndJmp(BC.MIB->matchAdd( 3940 BC.MIB->matchReg(BaseReg1), 3941 BC.MIB->matchLoad(BC.MIB->matchReg(BaseReg2), 3942 BC.MIB->matchImm(Scale), BC.MIB->matchReg(), 3943 BC.MIB->matchImm(Offset)))); 3944 std::unique_ptr<MCPlusBuilder::MCInstMatcher> LEAMatcherOwner = 3945 BC.MIB->matchLoadAddr(BC.MIB->matchSymbol(Target)); 3946 MCPlusBuilder::MCInstMatcher *LEAMatcher = LEAMatcherOwner.get(); 3947 std::unique_ptr<MCPlusBuilder::MCInstMatcher> PICBaseAddrMatcher = 3948 BC.MIB->matchIndJmp(BC.MIB->matchAdd(std::move(LEAMatcherOwner), 3949 BC.MIB->matchAnyOperand())); 3950 if (!PICIndJmpMatcher->match( 3951 *BC.MRI, *BC.MIB, 3952 MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1) || 3953 Scale != 4 || BaseReg1 != BaseReg2 || Offset != 0 || 3954 !PICBaseAddrMatcher->match( 3955 *BC.MRI, *BC.MIB, 3956 MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1)) { 3957 llvm_unreachable("Failed to extract jump table base"); 3958 continue; 3959 } 3960 // Matched PIC, identify the instruction with the reference to the JT 3961 JTLoadInst = LEAMatcher->CurInst; 3962 } else { 3963 // Matched non-PIC 3964 JTLoadInst = LoadMatcher->CurInst; 3965 } 3966 } 3967 3968 uint64_t NewJumpTableID = 0; 3969 const MCSymbol *NewJTLabel; 3970 std::tie(NewJumpTableID, NewJTLabel) = 3971 BC.duplicateJumpTable(*this, JT, Target); 3972 { 3973 auto L = BC.scopeLock(); 3974 BC.MIB->replaceMemOperandDisp(*JTLoadInst, NewJTLabel, BC.Ctx.get()); 3975 } 3976 // We use a unique ID with the high bit set as address for this "injected" 3977 // jump table (not originally in the input binary). 3978 BC.MIB->setJumpTable(Inst, NewJumpTableID, 0, AllocId); 3979 } 3980 } 3981 } 3982 3983 bool BinaryFunction::replaceJumpTableEntryIn(BinaryBasicBlock *BB, 3984 BinaryBasicBlock *OldDest, 3985 BinaryBasicBlock *NewDest) { 3986 MCInst *Instr = BB->getLastNonPseudoInstr(); 3987 if (!Instr || !BC.MIB->isIndirectBranch(*Instr)) 3988 return false; 3989 uint64_t JTAddress = BC.MIB->getJumpTable(*Instr); 3990 assert(JTAddress && "Invalid jump table address"); 3991 JumpTable *JT = getJumpTableContainingAddress(JTAddress); 3992 assert(JT && "No jump table structure for this indirect branch"); 3993 bool Patched = JT->replaceDestination(JTAddress, OldDest->getLabel(), 3994 NewDest->getLabel()); 3995 (void)Patched; 3996 assert(Patched && "Invalid entry to be replaced in jump table"); 3997 return true; 3998 } 3999 4000 BinaryBasicBlock *BinaryFunction::splitEdge(BinaryBasicBlock *From, 4001 BinaryBasicBlock *To) { 4002 // Create intermediate BB 4003 MCSymbol *Tmp; 4004 { 4005 auto L = BC.scopeLock(); 4006 Tmp = BC.Ctx->createNamedTempSymbol("SplitEdge"); 4007 } 4008 // Link new BBs to the original input offset of the From BB, so we can map 4009 // samples recorded in new BBs back to the original BB seem in the input 4010 // binary (if using BAT) 4011 std::unique_ptr<BinaryBasicBlock> NewBB = createBasicBlock(Tmp); 4012 NewBB->setOffset(From->getInputOffset()); 4013 BinaryBasicBlock *NewBBPtr = NewBB.get(); 4014 4015 // Update "From" BB 4016 auto I = From->succ_begin(); 4017 auto BI = From->branch_info_begin(); 4018 for (; I != From->succ_end(); ++I) { 4019 if (*I == To) 4020 break; 4021 ++BI; 4022 } 4023 assert(I != From->succ_end() && "Invalid CFG edge in splitEdge!"); 4024 uint64_t OrigCount = BI->Count; 4025 uint64_t OrigMispreds = BI->MispredictedCount; 4026 replaceJumpTableEntryIn(From, To, NewBBPtr); 4027 From->replaceSuccessor(To, NewBBPtr, OrigCount, OrigMispreds); 4028 4029 NewBB->addSuccessor(To, OrigCount, OrigMispreds); 4030 NewBB->setExecutionCount(OrigCount); 4031 NewBB->setIsCold(From->isCold()); 4032 4033 // Update CFI and BB layout with new intermediate BB 4034 std::vector<std::unique_ptr<BinaryBasicBlock>> NewBBs; 4035 NewBBs.emplace_back(std::move(NewBB)); 4036 insertBasicBlocks(From, std::move(NewBBs), true, true, 4037 /*RecomputeLandingPads=*/false); 4038 return NewBBPtr; 4039 } 4040 4041 void BinaryFunction::deleteConservativeEdges() { 4042 // Our goal is to aggressively remove edges from the CFG that we believe are 4043 // wrong. This is used for instrumentation, where it is safe to remove 4044 // fallthrough edges because we won't reorder blocks. 4045 for (auto I = BasicBlocks.begin(), E = BasicBlocks.end(); I != E; ++I) { 4046 BinaryBasicBlock *BB = *I; 4047 if (BB->succ_size() != 1 || BB->size() == 0) 4048 continue; 4049 4050 auto NextBB = std::next(I); 4051 MCInst *Last = BB->getLastNonPseudoInstr(); 4052 // Fallthrough is a landing pad? Delete this edge (as long as we don't 4053 // have a direct jump to it) 4054 if ((*BB->succ_begin())->isLandingPad() && NextBB != E && 4055 *BB->succ_begin() == *NextBB && Last && !BC.MIB->isBranch(*Last)) { 4056 BB->removeAllSuccessors(); 4057 continue; 4058 } 4059 4060 // Look for suspicious calls at the end of BB where gcc may optimize it and 4061 // remove the jump to the epilogue when it knows the call won't return. 4062 if (!Last || !BC.MIB->isCall(*Last)) 4063 continue; 4064 4065 const MCSymbol *CalleeSymbol = BC.MIB->getTargetSymbol(*Last); 4066 if (!CalleeSymbol) 4067 continue; 4068 4069 StringRef CalleeName = CalleeSymbol->getName(); 4070 if (CalleeName != "__cxa_throw@PLT" && CalleeName != "_Unwind_Resume@PLT" && 4071 CalleeName != "__cxa_rethrow@PLT" && CalleeName != "exit@PLT" && 4072 CalleeName != "abort@PLT") 4073 continue; 4074 4075 BB->removeAllSuccessors(); 4076 } 4077 } 4078 4079 bool BinaryFunction::isSymbolValidInScope(const SymbolRef &Symbol, 4080 uint64_t SymbolSize) const { 4081 // If this symbol is in a different section from the one where the 4082 // function symbol is, don't consider it as valid. 4083 if (!getOriginSection()->containsAddress( 4084 cantFail(Symbol.getAddress(), "cannot get symbol address"))) 4085 return false; 4086 4087 // Some symbols are tolerated inside function bodies, others are not. 4088 // The real function boundaries may not be known at this point. 4089 if (BC.isMarker(Symbol)) 4090 return true; 4091 4092 // It's okay to have a zero-sized symbol in the middle of non-zero-sized 4093 // function. 4094 if (SymbolSize == 0 && containsAddress(cantFail(Symbol.getAddress()))) 4095 return true; 4096 4097 if (cantFail(Symbol.getType()) != SymbolRef::ST_Unknown) 4098 return false; 4099 4100 if (cantFail(Symbol.getFlags()) & SymbolRef::SF_Global) 4101 return false; 4102 4103 return true; 4104 } 4105 4106 void BinaryFunction::adjustExecutionCount(uint64_t Count) { 4107 if (getKnownExecutionCount() == 0 || Count == 0) 4108 return; 4109 4110 if (ExecutionCount < Count) 4111 Count = ExecutionCount; 4112 4113 double AdjustmentRatio = ((double)ExecutionCount - Count) / ExecutionCount; 4114 if (AdjustmentRatio < 0.0) 4115 AdjustmentRatio = 0.0; 4116 4117 for (BinaryBasicBlock &BB : blocks()) 4118 BB.adjustExecutionCount(AdjustmentRatio); 4119 4120 ExecutionCount -= Count; 4121 } 4122 4123 BinaryFunction::~BinaryFunction() { 4124 for (BinaryBasicBlock *BB : BasicBlocks) 4125 delete BB; 4126 for (BinaryBasicBlock *BB : DeletedBasicBlocks) 4127 delete BB; 4128 } 4129 4130 void BinaryFunction::constructDomTree() { 4131 BDT.reset(new BinaryDominatorTree); 4132 BDT->recalculate(*this); 4133 } 4134 4135 void BinaryFunction::calculateLoopInfo() { 4136 if (!hasDomTree()) 4137 constructDomTree(); 4138 // Discover loops. 4139 BLI.reset(new BinaryLoopInfo()); 4140 BLI->analyze(getDomTree()); 4141 4142 // Traverse discovered loops and add depth and profile information. 4143 std::stack<BinaryLoop *> St; 4144 for (auto I = BLI->begin(), E = BLI->end(); I != E; ++I) { 4145 St.push(*I); 4146 ++BLI->OuterLoops; 4147 } 4148 4149 while (!St.empty()) { 4150 BinaryLoop *L = St.top(); 4151 St.pop(); 4152 ++BLI->TotalLoops; 4153 BLI->MaximumDepth = std::max(L->getLoopDepth(), BLI->MaximumDepth); 4154 4155 // Add nested loops in the stack. 4156 for (BinaryLoop::iterator I = L->begin(), E = L->end(); I != E; ++I) 4157 St.push(*I); 4158 4159 // Skip if no valid profile is found. 4160 if (!hasValidProfile()) { 4161 L->EntryCount = COUNT_NO_PROFILE; 4162 L->ExitCount = COUNT_NO_PROFILE; 4163 L->TotalBackEdgeCount = COUNT_NO_PROFILE; 4164 continue; 4165 } 4166 4167 // Compute back edge count. 4168 SmallVector<BinaryBasicBlock *, 1> Latches; 4169 L->getLoopLatches(Latches); 4170 4171 for (BinaryBasicBlock *Latch : Latches) { 4172 auto BI = Latch->branch_info_begin(); 4173 for (BinaryBasicBlock *Succ : Latch->successors()) { 4174 if (Succ == L->getHeader()) { 4175 assert(BI->Count != BinaryBasicBlock::COUNT_NO_PROFILE && 4176 "profile data not found"); 4177 L->TotalBackEdgeCount += BI->Count; 4178 } 4179 ++BI; 4180 } 4181 } 4182 4183 // Compute entry count. 4184 L->EntryCount = L->getHeader()->getExecutionCount() - L->TotalBackEdgeCount; 4185 4186 // Compute exit count. 4187 SmallVector<BinaryLoop::Edge, 1> ExitEdges; 4188 L->getExitEdges(ExitEdges); 4189 for (BinaryLoop::Edge &Exit : ExitEdges) { 4190 const BinaryBasicBlock *Exiting = Exit.first; 4191 const BinaryBasicBlock *ExitTarget = Exit.second; 4192 auto BI = Exiting->branch_info_begin(); 4193 for (BinaryBasicBlock *Succ : Exiting->successors()) { 4194 if (Succ == ExitTarget) { 4195 assert(BI->Count != BinaryBasicBlock::COUNT_NO_PROFILE && 4196 "profile data not found"); 4197 L->ExitCount += BI->Count; 4198 } 4199 ++BI; 4200 } 4201 } 4202 } 4203 } 4204 4205 void BinaryFunction::updateOutputValues(const BOLTLinker &Linker) { 4206 if (!isEmitted()) { 4207 assert(!isInjected() && "injected function should be emitted"); 4208 setOutputAddress(getAddress()); 4209 setOutputSize(getSize()); 4210 return; 4211 } 4212 4213 const auto SymbolInfo = Linker.lookupSymbolInfo(getSymbol()->getName()); 4214 assert(SymbolInfo && "Cannot find function entry symbol"); 4215 setOutputAddress(SymbolInfo->Address); 4216 setOutputSize(SymbolInfo->Size); 4217 4218 if (BC.HasRelocations || isInjected()) { 4219 if (hasConstantIsland()) { 4220 const auto DataAddress = 4221 Linker.lookupSymbol(getFunctionConstantIslandLabel()->getName()); 4222 assert(DataAddress && "Cannot find function CI symbol"); 4223 setOutputDataAddress(*DataAddress); 4224 for (auto It : Islands->Offsets) { 4225 const uint64_t OldOffset = It.first; 4226 BinaryData *BD = BC.getBinaryDataAtAddress(getAddress() + OldOffset); 4227 if (!BD) 4228 continue; 4229 4230 MCSymbol *Symbol = It.second; 4231 const auto NewAddress = Linker.lookupSymbol(Symbol->getName()); 4232 assert(NewAddress && "Cannot find CI symbol"); 4233 auto &Section = *getCodeSection(); 4234 const auto NewOffset = *NewAddress - Section.getOutputAddress(); 4235 BD->setOutputLocation(Section, NewOffset); 4236 } 4237 } 4238 if (isSplit()) { 4239 for (FunctionFragment &FF : getLayout().getSplitFragments()) { 4240 ErrorOr<BinarySection &> ColdSection = 4241 getCodeSection(FF.getFragmentNum()); 4242 // If fragment is empty, cold section might not exist 4243 if (FF.empty() && ColdSection.getError()) 4244 continue; 4245 4246 const MCSymbol *ColdStartSymbol = getSymbol(FF.getFragmentNum()); 4247 // If fragment is empty, symbol might have not been emitted 4248 if (FF.empty() && (!ColdStartSymbol || !ColdStartSymbol->isDefined()) && 4249 !hasConstantIsland()) 4250 continue; 4251 assert(ColdStartSymbol && ColdStartSymbol->isDefined() && 4252 "split function should have defined cold symbol"); 4253 const auto ColdStartSymbolInfo = 4254 Linker.lookupSymbolInfo(ColdStartSymbol->getName()); 4255 assert(ColdStartSymbolInfo && "Cannot find cold start symbol"); 4256 FF.setAddress(ColdStartSymbolInfo->Address); 4257 FF.setImageSize(ColdStartSymbolInfo->Size); 4258 if (hasConstantIsland()) { 4259 const auto DataAddress = Linker.lookupSymbol( 4260 getFunctionColdConstantIslandLabel()->getName()); 4261 assert(DataAddress && "Cannot find cold CI symbol"); 4262 setOutputColdDataAddress(*DataAddress); 4263 } 4264 } 4265 } 4266 } 4267 4268 // Update basic block output ranges for the debug info, if we have 4269 // secondary entry points in the symbol table to update or if writing BAT. 4270 if (!requiresAddressMap()) 4271 return; 4272 4273 // AArch64 may have functions that only contains a constant island (no code). 4274 if (getLayout().block_empty()) 4275 return; 4276 4277 for (FunctionFragment &FF : getLayout().fragments()) { 4278 if (FF.empty()) 4279 continue; 4280 4281 const uint64_t FragmentBaseAddress = 4282 getCodeSection(isSimple() ? FF.getFragmentNum() : FragmentNum::main()) 4283 ->getOutputAddress(); 4284 4285 BinaryBasicBlock *PrevBB = nullptr; 4286 for (BinaryBasicBlock *const BB : FF) { 4287 assert(BB->getLabel()->isDefined() && "symbol should be defined"); 4288 if (!BC.HasRelocations) { 4289 if (BB->isSplit()) 4290 assert(FragmentBaseAddress == FF.getAddress()); 4291 else 4292 assert(FragmentBaseAddress == getOutputAddress()); 4293 (void)FragmentBaseAddress; 4294 } 4295 4296 // Injected functions likely will fail lookup, as they have no 4297 // input range. Just assign the BB the output address of the 4298 // function. 4299 auto MaybeBBAddress = BC.getIOAddressMap().lookup(BB->getLabel()); 4300 const uint64_t BBAddress = MaybeBBAddress ? *MaybeBBAddress 4301 : BB->isSplit() ? FF.getAddress() 4302 : getOutputAddress(); 4303 BB->setOutputStartAddress(BBAddress); 4304 4305 if (PrevBB) { 4306 assert(PrevBB->getOutputAddressRange().first <= BBAddress && 4307 "Bad output address for basic block."); 4308 assert((PrevBB->getOutputAddressRange().first != BBAddress || 4309 !hasInstructions() || !PrevBB->getNumNonPseudos()) && 4310 "Bad output address for basic block."); 4311 PrevBB->setOutputEndAddress(BBAddress); 4312 } 4313 PrevBB = BB; 4314 } 4315 4316 PrevBB->setOutputEndAddress(PrevBB->isSplit() 4317 ? FF.getAddress() + FF.getImageSize() 4318 : getOutputAddress() + getOutputSize()); 4319 } 4320 4321 // Reset output addresses for deleted blocks. 4322 for (BinaryBasicBlock *BB : DeletedBasicBlocks) { 4323 BB->setOutputStartAddress(0); 4324 BB->setOutputEndAddress(0); 4325 } 4326 } 4327 4328 DebugAddressRangesVector BinaryFunction::getOutputAddressRanges() const { 4329 DebugAddressRangesVector OutputRanges; 4330 4331 if (isFolded()) 4332 return OutputRanges; 4333 4334 if (IsFragment) 4335 return OutputRanges; 4336 4337 OutputRanges.emplace_back(getOutputAddress(), 4338 getOutputAddress() + getOutputSize()); 4339 if (isSplit()) { 4340 assert(isEmitted() && "split function should be emitted"); 4341 for (const FunctionFragment &FF : getLayout().getSplitFragments()) 4342 OutputRanges.emplace_back(FF.getAddress(), 4343 FF.getAddress() + FF.getImageSize()); 4344 } 4345 4346 if (isSimple()) 4347 return OutputRanges; 4348 4349 for (BinaryFunction *Frag : Fragments) { 4350 assert(!Frag->isSimple() && 4351 "fragment of non-simple function should also be non-simple"); 4352 OutputRanges.emplace_back(Frag->getOutputAddress(), 4353 Frag->getOutputAddress() + Frag->getOutputSize()); 4354 } 4355 4356 return OutputRanges; 4357 } 4358 4359 uint64_t BinaryFunction::translateInputToOutputAddress(uint64_t Address) const { 4360 if (isFolded()) 4361 return 0; 4362 4363 // If the function hasn't changed return the same address. 4364 if (!isEmitted()) 4365 return Address; 4366 4367 if (Address < getAddress()) 4368 return 0; 4369 4370 // Check if the address is associated with an instruction that is tracked 4371 // by address translation. 4372 if (auto OutputAddress = BC.getIOAddressMap().lookup(Address)) 4373 return *OutputAddress; 4374 4375 // FIXME: #18950828 - we rely on relative offsets inside basic blocks to stay 4376 // intact. Instead we can use pseudo instructions and/or annotations. 4377 const uint64_t Offset = Address - getAddress(); 4378 const BinaryBasicBlock *BB = getBasicBlockContainingOffset(Offset); 4379 if (!BB) { 4380 // Special case for address immediately past the end of the function. 4381 if (Offset == getSize()) 4382 return getOutputAddress() + getOutputSize(); 4383 4384 return 0; 4385 } 4386 4387 return std::min(BB->getOutputAddressRange().first + Offset - BB->getOffset(), 4388 BB->getOutputAddressRange().second); 4389 } 4390 4391 DebugAddressRangesVector 4392 BinaryFunction::translateInputToOutputRange(DebugAddressRange InRange) const { 4393 DebugAddressRangesVector OutRanges; 4394 4395 // The function was removed from the output. Return an empty range. 4396 if (isFolded()) 4397 return OutRanges; 4398 4399 // If the function hasn't changed return the same range. 4400 if (!isEmitted()) { 4401 OutRanges.emplace_back(InRange); 4402 return OutRanges; 4403 } 4404 4405 if (!containsAddress(InRange.LowPC)) 4406 return OutRanges; 4407 4408 // Special case of an empty range [X, X). Some tools expect X to be updated. 4409 if (InRange.LowPC == InRange.HighPC) { 4410 if (uint64_t NewPC = translateInputToOutputAddress(InRange.LowPC)) 4411 OutRanges.push_back(DebugAddressRange{NewPC, NewPC}); 4412 return OutRanges; 4413 } 4414 4415 uint64_t InputOffset = InRange.LowPC - getAddress(); 4416 const uint64_t InputEndOffset = 4417 std::min(InRange.HighPC - getAddress(), getSize()); 4418 4419 auto BBI = llvm::upper_bound(BasicBlockOffsets, 4420 BasicBlockOffset(InputOffset, nullptr), 4421 CompareBasicBlockOffsets()); 4422 assert(BBI != BasicBlockOffsets.begin()); 4423 4424 // Iterate over blocks in the input order using BasicBlockOffsets. 4425 for (--BBI; InputOffset < InputEndOffset && BBI != BasicBlockOffsets.end(); 4426 InputOffset = BBI->second->getEndOffset(), ++BBI) { 4427 const BinaryBasicBlock &BB = *BBI->second; 4428 if (InputOffset < BB.getOffset() || InputOffset >= BB.getEndOffset()) { 4429 LLVM_DEBUG( 4430 dbgs() << "BOLT-DEBUG: invalid debug address range detected for " 4431 << *this << " : [0x" << Twine::utohexstr(InRange.LowPC) 4432 << ", 0x" << Twine::utohexstr(InRange.HighPC) << "]\n"); 4433 break; 4434 } 4435 4436 // Skip the block if it wasn't emitted. 4437 if (!BB.getOutputAddressRange().first) 4438 continue; 4439 4440 // Find output address for an instruction with an offset greater or equal 4441 // to /p Offset. The output address should fall within the same basic 4442 // block boundaries. 4443 auto translateBlockOffset = [&](const uint64_t Offset) { 4444 const uint64_t OutAddress = BB.getOutputAddressRange().first + Offset; 4445 return std::min(OutAddress, BB.getOutputAddressRange().second); 4446 }; 4447 4448 uint64_t OutLowPC = BB.getOutputAddressRange().first; 4449 if (InputOffset > BB.getOffset()) 4450 OutLowPC = translateBlockOffset(InputOffset - BB.getOffset()); 4451 4452 uint64_t OutHighPC = BB.getOutputAddressRange().second; 4453 if (InputEndOffset < BB.getEndOffset()) { 4454 assert(InputEndOffset >= BB.getOffset()); 4455 OutHighPC = translateBlockOffset(InputEndOffset - BB.getOffset()); 4456 } 4457 4458 // Check if we can expand the last translated range. 4459 if (!OutRanges.empty() && OutRanges.back().HighPC == OutLowPC) 4460 OutRanges.back().HighPC = std::max(OutRanges.back().HighPC, OutHighPC); 4461 else 4462 OutRanges.emplace_back(OutLowPC, std::max(OutLowPC, OutHighPC)); 4463 } 4464 4465 LLVM_DEBUG({ 4466 dbgs() << "BOLT-DEBUG: translated address range " << InRange << " -> "; 4467 for (const DebugAddressRange &R : OutRanges) 4468 dbgs() << R << ' '; 4469 dbgs() << '\n'; 4470 }); 4471 4472 return OutRanges; 4473 } 4474 4475 MCInst *BinaryFunction::getInstructionAtOffset(uint64_t Offset) { 4476 if (CurrentState == State::Disassembled) { 4477 auto II = Instructions.find(Offset); 4478 return (II == Instructions.end()) ? nullptr : &II->second; 4479 } else if (CurrentState == State::CFG) { 4480 BinaryBasicBlock *BB = getBasicBlockContainingOffset(Offset); 4481 if (!BB) 4482 return nullptr; 4483 4484 for (MCInst &Inst : *BB) { 4485 constexpr uint32_t InvalidOffset = std::numeric_limits<uint32_t>::max(); 4486 if (Offset == BC.MIB->getOffsetWithDefault(Inst, InvalidOffset)) 4487 return &Inst; 4488 } 4489 4490 if (MCInst *LastInstr = BB->getLastNonPseudoInstr()) { 4491 if (std::optional<uint32_t> Size = BC.MIB->getSize(*LastInstr)) { 4492 if (BB->getEndOffset() - Offset == Size) { 4493 return LastInstr; 4494 } 4495 } 4496 } 4497 4498 return nullptr; 4499 } else { 4500 llvm_unreachable("invalid CFG state to use getInstructionAtOffset()"); 4501 } 4502 } 4503 4504 MCInst *BinaryFunction::getInstructionContainingOffset(uint64_t Offset) { 4505 assert(CurrentState == State::Disassembled && "Wrong function state"); 4506 4507 if (Offset > Size) 4508 return nullptr; 4509 4510 auto II = Instructions.upper_bound(Offset); 4511 assert(II != Instructions.begin() && "First instruction not at offset 0"); 4512 --II; 4513 return &II->second; 4514 } 4515 4516 void BinaryFunction::printLoopInfo(raw_ostream &OS) const { 4517 if (!opts::shouldPrint(*this)) 4518 return; 4519 4520 OS << "Loop Info for Function \"" << *this << "\""; 4521 if (hasValidProfile()) 4522 OS << " (count: " << getExecutionCount() << ")"; 4523 OS << "\n"; 4524 4525 std::stack<BinaryLoop *> St; 4526 for (BinaryLoop *L : *BLI) 4527 St.push(L); 4528 while (!St.empty()) { 4529 BinaryLoop *L = St.top(); 4530 St.pop(); 4531 4532 for (BinaryLoop *Inner : *L) 4533 St.push(Inner); 4534 4535 if (!hasValidProfile()) 4536 continue; 4537 4538 OS << (L->getLoopDepth() > 1 ? "Nested" : "Outer") 4539 << " loop header: " << L->getHeader()->getName(); 4540 OS << "\n"; 4541 OS << "Loop basic blocks: "; 4542 ListSeparator LS; 4543 for (BinaryBasicBlock *BB : L->blocks()) 4544 OS << LS << BB->getName(); 4545 OS << "\n"; 4546 if (hasValidProfile()) { 4547 OS << "Total back edge count: " << L->TotalBackEdgeCount << "\n"; 4548 OS << "Loop entry count: " << L->EntryCount << "\n"; 4549 OS << "Loop exit count: " << L->ExitCount << "\n"; 4550 if (L->EntryCount > 0) { 4551 OS << "Average iters per entry: " 4552 << format("%.4lf", (double)L->TotalBackEdgeCount / L->EntryCount) 4553 << "\n"; 4554 } 4555 } 4556 OS << "----\n"; 4557 } 4558 4559 OS << "Total number of loops: " << BLI->TotalLoops << "\n"; 4560 OS << "Number of outer loops: " << BLI->OuterLoops << "\n"; 4561 OS << "Maximum nested loop depth: " << BLI->MaximumDepth << "\n\n"; 4562 } 4563 4564 bool BinaryFunction::isAArch64Veneer() const { 4565 if (empty() || hasIslandsInfo()) 4566 return false; 4567 4568 BinaryBasicBlock &BB = **BasicBlocks.begin(); 4569 for (MCInst &Inst : BB) 4570 if (!BC.MIB->hasAnnotation(Inst, "AArch64Veneer")) 4571 return false; 4572 4573 for (auto I = BasicBlocks.begin() + 1, E = BasicBlocks.end(); I != E; ++I) { 4574 for (MCInst &Inst : **I) 4575 if (!BC.MIB->isNoop(Inst)) 4576 return false; 4577 } 4578 4579 return true; 4580 } 4581 4582 void BinaryFunction::addRelocation(uint64_t Address, MCSymbol *Symbol, 4583 uint64_t RelType, uint64_t Addend, 4584 uint64_t Value) { 4585 assert(Address >= getAddress() && Address < getAddress() + getMaxSize() && 4586 "address is outside of the function"); 4587 uint64_t Offset = Address - getAddress(); 4588 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: addRelocation in " 4589 << formatv("{0}@{1:x} against {2}\n", *this, Offset, 4590 (Symbol ? Symbol->getName() : "<undef>"))); 4591 bool IsCI = BC.isAArch64() && isInConstantIsland(Address); 4592 std::map<uint64_t, Relocation> &Rels = 4593 IsCI ? Islands->Relocations : Relocations; 4594 if (BC.MIB->shouldRecordCodeRelocation(RelType)) 4595 Rels[Offset] = Relocation{Offset, Symbol, RelType, Addend, Value}; 4596 } 4597 4598 } // namespace bolt 4599 } // namespace llvm 4600