xref: /llvm-project/bolt/lib/Core/BinaryFunction.cpp (revision 74003f11b3e4dd90665f8f8d911f40a22dd940d4)
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 
389     if (hasValidIndex() && CalleeBF->hasValidIndex()) {
390       return getIndex() < CalleeBF->getIndex();
391     } else if (hasValidIndex() && !CalleeBF->hasValidIndex()) {
392       return true;
393     } else if (!hasValidIndex() && CalleeBF->hasValidIndex()) {
394       return false;
395     } else {
396       return getAddress() < CalleeBF->getAddress();
397     }
398   } else {
399     // Absolute symbol.
400     ErrorOr<uint64_t> CalleeAddressOrError = BC.getSymbolValue(*CalleeSymbol);
401     assert(CalleeAddressOrError && "unregistered symbol found");
402     return *CalleeAddressOrError > getAddress();
403   }
404 }
405 
406 void BinaryFunction::dump() const {
407   // getDynoStats calls FunctionLayout::updateLayoutIndices and
408   // BasicBlock::analyzeBranch. The former cannot be const, but should be
409   // removed, the latter should be made const, but seems to require refactoring.
410   // Forcing all callers to have a non-const reference to BinaryFunction to call
411   // dump non-const however is not ideal either. Adding this const_cast is right
412   // now the best solution. It is safe, because BinaryFunction itself is not
413   // modified. Only BinaryBasicBlocks are actually modified (if it all) and we
414   // have mutable pointers to those regardless whether this function is
415   // const-qualified or not.
416   const_cast<BinaryFunction &>(*this).print(dbgs(), "");
417 }
418 
419 void BinaryFunction::print(raw_ostream &OS, std::string Annotation) {
420   if (!opts::shouldPrint(*this))
421     return;
422 
423   StringRef SectionName =
424       OriginSection ? OriginSection->getName() : "<no origin section>";
425   OS << "Binary Function \"" << *this << "\" " << Annotation << " {";
426   std::vector<StringRef> AllNames = getNames();
427   if (AllNames.size() > 1) {
428     OS << "\n  All names   : ";
429     const char *Sep = "";
430     for (const StringRef &Name : AllNames) {
431       OS << Sep << Name;
432       Sep = "\n                ";
433     }
434   }
435   OS << "\n  Number      : " << FunctionNumber;
436   OS << "\n  State       : " << CurrentState;
437   OS << "\n  Address     : 0x" << Twine::utohexstr(Address);
438   OS << "\n  Size        : 0x" << Twine::utohexstr(Size);
439   OS << "\n  MaxSize     : 0x" << Twine::utohexstr(MaxSize);
440   OS << "\n  Offset      : 0x" << Twine::utohexstr(getFileOffset());
441   OS << "\n  Section     : " << SectionName;
442   OS << "\n  Orc Section : " << getCodeSectionName();
443   OS << "\n  LSDA        : 0x" << Twine::utohexstr(getLSDAAddress());
444   OS << "\n  IsSimple    : " << IsSimple;
445   OS << "\n  IsMultiEntry: " << isMultiEntry();
446   OS << "\n  IsSplit     : " << isSplit();
447   OS << "\n  BB Count    : " << size();
448 
449   if (HasUnknownControlFlow)
450     OS << "\n  Unknown CF  : true";
451   if (getPersonalityFunction())
452     OS << "\n  Personality : " << getPersonalityFunction()->getName();
453   if (IsFragment)
454     OS << "\n  IsFragment  : true";
455   if (isFolded())
456     OS << "\n  FoldedInto  : " << *getFoldedIntoFunction();
457   for (BinaryFunction *ParentFragment : ParentFragments)
458     OS << "\n  Parent      : " << *ParentFragment;
459   if (!Fragments.empty()) {
460     OS << "\n  Fragments   : ";
461     ListSeparator LS;
462     for (BinaryFunction *Frag : Fragments)
463       OS << LS << *Frag;
464   }
465   if (hasCFG())
466     OS << "\n  Hash        : " << Twine::utohexstr(computeHash());
467   if (isMultiEntry()) {
468     OS << "\n  Secondary Entry Points : ";
469     ListSeparator LS;
470     for (const auto &KV : SecondaryEntryPoints)
471       OS << LS << KV.second->getName();
472   }
473   if (FrameInstructions.size())
474     OS << "\n  CFI Instrs  : " << FrameInstructions.size();
475   if (!Layout.block_empty()) {
476     OS << "\n  BB Layout   : ";
477     ListSeparator LS;
478     for (const BinaryBasicBlock *BB : Layout.blocks())
479       OS << LS << BB->getName();
480   }
481   if (getImageAddress())
482     OS << "\n  Image       : 0x" << Twine::utohexstr(getImageAddress());
483   if (ExecutionCount != COUNT_NO_PROFILE) {
484     OS << "\n  Exec Count  : " << ExecutionCount;
485     OS << "\n  Branch Count: " << RawBranchCount;
486     OS << "\n  Profile Acc : " << format("%.1f%%", ProfileMatchRatio * 100.0f);
487   }
488 
489   if (opts::PrintDynoStats && !getLayout().block_empty()) {
490     OS << '\n';
491     DynoStats dynoStats = getDynoStats(*this);
492     OS << dynoStats;
493   }
494 
495   OS << "\n}\n";
496 
497   if (opts::PrintDynoStatsOnly || !BC.InstPrinter)
498     return;
499 
500   // Offset of the instruction in function.
501   uint64_t Offset = 0;
502 
503   if (BasicBlocks.empty() && !Instructions.empty()) {
504     // Print before CFG was built.
505     for (const std::pair<const uint32_t, MCInst> &II : Instructions) {
506       Offset = II.first;
507 
508       // Print label if exists at this offset.
509       auto LI = Labels.find(Offset);
510       if (LI != Labels.end()) {
511         if (const MCSymbol *EntrySymbol =
512                 getSecondaryEntryPointSymbol(LI->second))
513           OS << EntrySymbol->getName() << " (Entry Point):\n";
514         OS << LI->second->getName() << ":\n";
515       }
516 
517       BC.printInstruction(OS, II.second, Offset, this);
518     }
519   }
520 
521   StringRef SplitPointMsg = "";
522   for (const FunctionFragment &FF : Layout.fragments()) {
523     OS << SplitPointMsg;
524     SplitPointMsg = "-------   HOT-COLD SPLIT POINT   -------\n\n";
525     for (const BinaryBasicBlock *BB : FF) {
526       OS << BB->getName() << " (" << BB->size()
527          << " instructions, align : " << BB->getAlignment() << ")\n";
528 
529       if (opts::PrintOutputAddressRange)
530         OS << formatv("  Output Address Range: [{0:x}, {1:x}) ({2} bytes)\n",
531                       BB->getOutputAddressRange().first,
532                       BB->getOutputAddressRange().second, BB->getOutputSize());
533 
534       if (isEntryPoint(*BB)) {
535         if (MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(*BB))
536           OS << "  Secondary Entry Point: " << EntrySymbol->getName() << '\n';
537         else
538           OS << "  Entry Point\n";
539       }
540 
541       if (BB->isLandingPad())
542         OS << "  Landing Pad\n";
543 
544       uint64_t BBExecCount = BB->getExecutionCount();
545       if (hasValidProfile()) {
546         OS << "  Exec Count : ";
547         if (BB->getExecutionCount() != BinaryBasicBlock::COUNT_NO_PROFILE)
548           OS << BBExecCount << '\n';
549         else
550           OS << "<unknown>\n";
551       }
552       if (hasCFI())
553         OS << "  CFI State : " << BB->getCFIState() << '\n';
554       if (opts::EnableBAT) {
555         OS << "  Input offset: 0x" << Twine::utohexstr(BB->getInputOffset())
556            << "\n";
557       }
558       if (!BB->pred_empty()) {
559         OS << "  Predecessors: ";
560         ListSeparator LS;
561         for (BinaryBasicBlock *Pred : BB->predecessors())
562           OS << LS << Pred->getName();
563         OS << '\n';
564       }
565       if (!BB->throw_empty()) {
566         OS << "  Throwers: ";
567         ListSeparator LS;
568         for (BinaryBasicBlock *Throw : BB->throwers())
569           OS << LS << Throw->getName();
570         OS << '\n';
571       }
572 
573       Offset = alignTo(Offset, BB->getAlignment());
574 
575       // Note: offsets are imprecise since this is happening prior to
576       // relaxation.
577       Offset = BC.printInstructions(OS, BB->begin(), BB->end(), Offset, this);
578 
579       if (!BB->succ_empty()) {
580         OS << "  Successors: ";
581         // For more than 2 successors, sort them based on frequency.
582         std::vector<uint64_t> Indices(BB->succ_size());
583         std::iota(Indices.begin(), Indices.end(), 0);
584         if (BB->succ_size() > 2 && BB->getKnownExecutionCount()) {
585           llvm::stable_sort(Indices, [&](const uint64_t A, const uint64_t B) {
586             return BB->BranchInfo[B] < BB->BranchInfo[A];
587           });
588         }
589         ListSeparator LS;
590         for (unsigned I = 0; I < Indices.size(); ++I) {
591           BinaryBasicBlock *Succ = BB->Successors[Indices[I]];
592           const BinaryBasicBlock::BinaryBranchInfo &BI =
593               BB->BranchInfo[Indices[I]];
594           OS << LS << Succ->getName();
595           if (ExecutionCount != COUNT_NO_PROFILE &&
596               BI.MispredictedCount != BinaryBasicBlock::COUNT_INFERRED) {
597             OS << " (mispreds: " << BI.MispredictedCount
598                << ", count: " << BI.Count << ")";
599           } else if (ExecutionCount != COUNT_NO_PROFILE &&
600                      BI.Count != BinaryBasicBlock::COUNT_NO_PROFILE) {
601             OS << " (inferred count: " << BI.Count << ")";
602           }
603         }
604         OS << '\n';
605       }
606 
607       if (!BB->lp_empty()) {
608         OS << "  Landing Pads: ";
609         ListSeparator LS;
610         for (BinaryBasicBlock *LP : BB->landing_pads()) {
611           OS << LS << LP->getName();
612           if (ExecutionCount != COUNT_NO_PROFILE) {
613             OS << " (count: " << LP->getExecutionCount() << ")";
614           }
615         }
616         OS << '\n';
617       }
618 
619       // In CFG_Finalized state we can miscalculate CFI state at exit.
620       if (CurrentState == State::CFG && hasCFI()) {
621         const int32_t CFIStateAtExit = BB->getCFIStateAtExit();
622         if (CFIStateAtExit >= 0)
623           OS << "  CFI State: " << CFIStateAtExit << '\n';
624       }
625 
626       OS << '\n';
627     }
628   }
629 
630   // Dump new exception ranges for the function.
631   if (!CallSites.empty()) {
632     OS << "EH table:\n";
633     for (const FunctionFragment &FF : getLayout().fragments()) {
634       for (const auto &FCSI : getCallSites(FF.getFragmentNum())) {
635         const CallSite &CSI = FCSI.second;
636         OS << "  [" << *CSI.Start << ", " << *CSI.End << ") landing pad : ";
637         if (CSI.LP)
638           OS << *CSI.LP;
639         else
640           OS << "0";
641         OS << ", action : " << CSI.Action << '\n';
642       }
643     }
644     OS << '\n';
645   }
646 
647   // Print all jump tables.
648   for (const std::pair<const uint64_t, JumpTable *> &JTI : JumpTables)
649     JTI.second->print(OS);
650 
651   OS << "DWARF CFI Instructions:\n";
652   if (OffsetToCFI.size()) {
653     // Pre-buildCFG information
654     for (const std::pair<const uint32_t, uint32_t> &Elmt : OffsetToCFI) {
655       OS << format("    %08x:\t", Elmt.first);
656       assert(Elmt.second < FrameInstructions.size() && "Incorrect CFI offset");
657       BinaryContext::printCFI(OS, FrameInstructions[Elmt.second]);
658       OS << "\n";
659     }
660   } else {
661     // Post-buildCFG information
662     for (uint32_t I = 0, E = FrameInstructions.size(); I != E; ++I) {
663       const MCCFIInstruction &CFI = FrameInstructions[I];
664       OS << format("    %d:\t", I);
665       BinaryContext::printCFI(OS, CFI);
666       OS << "\n";
667     }
668   }
669   if (FrameInstructions.empty())
670     OS << "    <empty>\n";
671 
672   OS << "End of Function \"" << *this << "\"\n\n";
673 }
674 
675 void BinaryFunction::printRelocations(raw_ostream &OS, uint64_t Offset,
676                                       uint64_t Size) const {
677   const char *Sep = " # Relocs: ";
678 
679   auto RI = Relocations.lower_bound(Offset);
680   while (RI != Relocations.end() && RI->first < Offset + Size) {
681     OS << Sep << "(R: " << RI->second << ")";
682     Sep = ", ";
683     ++RI;
684   }
685 }
686 
687 static std::string mutateDWARFExpressionTargetReg(const MCCFIInstruction &Instr,
688                                                   MCPhysReg NewReg) {
689   StringRef ExprBytes = Instr.getValues();
690   assert(ExprBytes.size() > 1 && "DWARF expression CFI is too short");
691   uint8_t Opcode = ExprBytes[0];
692   assert((Opcode == dwarf::DW_CFA_expression ||
693           Opcode == dwarf::DW_CFA_val_expression) &&
694          "invalid DWARF expression CFI");
695   (void)Opcode;
696   const uint8_t *const Start =
697       reinterpret_cast<const uint8_t *>(ExprBytes.drop_front(1).data());
698   const uint8_t *const End =
699       reinterpret_cast<const uint8_t *>(Start + ExprBytes.size() - 1);
700   unsigned Size = 0;
701   decodeULEB128(Start, &Size, End);
702   assert(Size > 0 && "Invalid reg encoding for DWARF expression CFI");
703   SmallString<8> Tmp;
704   raw_svector_ostream OSE(Tmp);
705   encodeULEB128(NewReg, OSE);
706   return Twine(ExprBytes.slice(0, 1))
707       .concat(OSE.str())
708       .concat(ExprBytes.drop_front(1 + Size))
709       .str();
710 }
711 
712 void BinaryFunction::mutateCFIRegisterFor(const MCInst &Instr,
713                                           MCPhysReg NewReg) {
714   const MCCFIInstruction *OldCFI = getCFIFor(Instr);
715   assert(OldCFI && "invalid CFI instr");
716   switch (OldCFI->getOperation()) {
717   default:
718     llvm_unreachable("Unexpected instruction");
719   case MCCFIInstruction::OpDefCfa:
720     setCFIFor(Instr, MCCFIInstruction::cfiDefCfa(nullptr, NewReg,
721                                                  OldCFI->getOffset()));
722     break;
723   case MCCFIInstruction::OpDefCfaRegister:
724     setCFIFor(Instr, MCCFIInstruction::createDefCfaRegister(nullptr, NewReg));
725     break;
726   case MCCFIInstruction::OpOffset:
727     setCFIFor(Instr, MCCFIInstruction::createOffset(nullptr, NewReg,
728                                                     OldCFI->getOffset()));
729     break;
730   case MCCFIInstruction::OpRegister:
731     setCFIFor(Instr, MCCFIInstruction::createRegister(nullptr, NewReg,
732                                                       OldCFI->getRegister2()));
733     break;
734   case MCCFIInstruction::OpSameValue:
735     setCFIFor(Instr, MCCFIInstruction::createSameValue(nullptr, NewReg));
736     break;
737   case MCCFIInstruction::OpEscape:
738     setCFIFor(Instr,
739               MCCFIInstruction::createEscape(
740                   nullptr,
741                   StringRef(mutateDWARFExpressionTargetReg(*OldCFI, NewReg))));
742     break;
743   case MCCFIInstruction::OpRestore:
744     setCFIFor(Instr, MCCFIInstruction::createRestore(nullptr, NewReg));
745     break;
746   case MCCFIInstruction::OpUndefined:
747     setCFIFor(Instr, MCCFIInstruction::createUndefined(nullptr, NewReg));
748     break;
749   }
750 }
751 
752 const MCCFIInstruction *BinaryFunction::mutateCFIOffsetFor(const MCInst &Instr,
753                                                            int64_t NewOffset) {
754   const MCCFIInstruction *OldCFI = getCFIFor(Instr);
755   assert(OldCFI && "invalid CFI instr");
756   switch (OldCFI->getOperation()) {
757   default:
758     llvm_unreachable("Unexpected instruction");
759   case MCCFIInstruction::OpDefCfaOffset:
760     setCFIFor(Instr, MCCFIInstruction::cfiDefCfaOffset(nullptr, NewOffset));
761     break;
762   case MCCFIInstruction::OpAdjustCfaOffset:
763     setCFIFor(Instr,
764               MCCFIInstruction::createAdjustCfaOffset(nullptr, NewOffset));
765     break;
766   case MCCFIInstruction::OpDefCfa:
767     setCFIFor(Instr, MCCFIInstruction::cfiDefCfa(nullptr, OldCFI->getRegister(),
768                                                  NewOffset));
769     break;
770   case MCCFIInstruction::OpOffset:
771     setCFIFor(Instr, MCCFIInstruction::createOffset(
772                          nullptr, OldCFI->getRegister(), NewOffset));
773     break;
774   }
775   return getCFIFor(Instr);
776 }
777 
778 IndirectBranchType
779 BinaryFunction::processIndirectBranch(MCInst &Instruction, unsigned Size,
780                                       uint64_t Offset,
781                                       uint64_t &TargetAddress) {
782   const unsigned PtrSize = BC.AsmInfo->getCodePointerSize();
783 
784   // The instruction referencing memory used by the branch instruction.
785   // It could be the branch instruction itself or one of the instructions
786   // setting the value of the register used by the branch.
787   MCInst *MemLocInstr;
788 
789   // The instruction loading the fixed PIC jump table entry value.
790   MCInst *FixedEntryLoadInstr;
791 
792   // Address of the table referenced by MemLocInstr. Could be either an
793   // array of function pointers, or a jump table.
794   uint64_t ArrayStart = 0;
795 
796   unsigned BaseRegNum, IndexRegNum;
797   int64_t DispValue;
798   const MCExpr *DispExpr;
799 
800   // In AArch, identify the instruction adding the PC-relative offset to
801   // jump table entries to correctly decode it.
802   MCInst *PCRelBaseInstr;
803   uint64_t PCRelAddr = 0;
804 
805   auto Begin = Instructions.begin();
806   if (BC.isAArch64()) {
807     PreserveNops = BC.HasRelocations;
808     // Start at the last label as an approximation of the current basic block.
809     // This is a heuristic, since the full set of labels have yet to be
810     // determined
811     for (const uint32_t Offset :
812          llvm::make_first_range(llvm::reverse(Labels))) {
813       auto II = Instructions.find(Offset);
814       if (II != Instructions.end()) {
815         Begin = II;
816         break;
817       }
818     }
819   }
820 
821   IndirectBranchType BranchType = BC.MIB->analyzeIndirectBranch(
822       Instruction, Begin, Instructions.end(), PtrSize, MemLocInstr, BaseRegNum,
823       IndexRegNum, DispValue, DispExpr, PCRelBaseInstr, FixedEntryLoadInstr);
824 
825   if (BranchType == IndirectBranchType::UNKNOWN && !MemLocInstr)
826     return BranchType;
827 
828   if (MemLocInstr != &Instruction)
829     IndexRegNum = BC.MIB->getNoRegister();
830 
831   if (BC.isAArch64()) {
832     const MCSymbol *Sym = BC.MIB->getTargetSymbol(*PCRelBaseInstr, 1);
833     assert(Sym && "Symbol extraction failed");
834     ErrorOr<uint64_t> SymValueOrError = BC.getSymbolValue(*Sym);
835     if (SymValueOrError) {
836       PCRelAddr = *SymValueOrError;
837     } else {
838       for (std::pair<const uint32_t, MCSymbol *> &Elmt : Labels) {
839         if (Elmt.second == Sym) {
840           PCRelAddr = Elmt.first + getAddress();
841           break;
842         }
843       }
844     }
845     uint64_t InstrAddr = 0;
846     for (auto II = Instructions.rbegin(); II != Instructions.rend(); ++II) {
847       if (&II->second == PCRelBaseInstr) {
848         InstrAddr = II->first + getAddress();
849         break;
850       }
851     }
852     assert(InstrAddr != 0 && "instruction not found");
853     // We do this to avoid spurious references to code locations outside this
854     // function (for example, if the indirect jump lives in the last basic
855     // block of the function, it will create a reference to the next function).
856     // This replaces a symbol reference with an immediate.
857     BC.MIB->replaceMemOperandDisp(*PCRelBaseInstr,
858                                   MCOperand::createImm(PCRelAddr - InstrAddr));
859     // FIXME: Disable full jump table processing for AArch64 until we have a
860     // proper way of determining the jump table limits.
861     return IndirectBranchType::UNKNOWN;
862   }
863 
864   auto getExprValue = [&](const MCExpr *Expr) {
865     const MCSymbol *TargetSym;
866     uint64_t TargetOffset;
867     std::tie(TargetSym, TargetOffset) = BC.MIB->getTargetSymbolInfo(Expr);
868     ErrorOr<uint64_t> SymValueOrError = BC.getSymbolValue(*TargetSym);
869     assert(SymValueOrError && "Global symbol needs a value");
870     return *SymValueOrError + TargetOffset;
871   };
872 
873   // RIP-relative addressing should be converted to symbol form by now
874   // in processed instructions (but not in jump).
875   if (DispExpr) {
876     ArrayStart = getExprValue(DispExpr);
877     BaseRegNum = BC.MIB->getNoRegister();
878     if (BC.isAArch64()) {
879       ArrayStart &= ~0xFFFULL;
880       ArrayStart += DispValue & 0xFFFULL;
881     }
882   } else {
883     ArrayStart = static_cast<uint64_t>(DispValue);
884   }
885 
886   if (BaseRegNum == BC.MRI->getProgramCounter())
887     ArrayStart += getAddress() + Offset + Size;
888 
889   if (FixedEntryLoadInstr) {
890     assert(BranchType == IndirectBranchType::POSSIBLE_PIC_FIXED_BRANCH &&
891            "Invalid IndirectBranch type");
892     MCInst::iterator FixedEntryDispOperand =
893         BC.MIB->getMemOperandDisp(*FixedEntryLoadInstr);
894     assert(FixedEntryDispOperand != FixedEntryLoadInstr->end() &&
895            "Invalid memory instruction");
896     const MCExpr *FixedEntryDispExpr = FixedEntryDispOperand->getExpr();
897     const uint64_t EntryAddress = getExprValue(FixedEntryDispExpr);
898     uint64_t EntrySize = BC.getJumpTableEntrySize(JumpTable::JTT_PIC);
899     ErrorOr<int64_t> Value =
900         BC.getSignedValueAtAddress(EntryAddress, EntrySize);
901     if (!Value)
902       return IndirectBranchType::UNKNOWN;
903 
904     BC.outs() << "BOLT-INFO: fixed PIC indirect branch detected in " << *this
905               << " at 0x" << Twine::utohexstr(getAddress() + Offset)
906               << " referencing data at 0x" << Twine::utohexstr(EntryAddress)
907               << " the destination value is 0x"
908               << Twine::utohexstr(ArrayStart + *Value) << '\n';
909 
910     TargetAddress = ArrayStart + *Value;
911 
912     // Remove spurious JumpTable at EntryAddress caused by PIC reference from
913     // the load instruction.
914     BC.deleteJumpTable(EntryAddress);
915 
916     // Replace FixedEntryDispExpr used in target address calculation with outer
917     // jump table reference.
918     JumpTable *JT = BC.getJumpTableContainingAddress(ArrayStart);
919     assert(JT && "Must have a containing jump table for PIC fixed branch");
920     BC.MIB->replaceMemOperandDisp(*FixedEntryLoadInstr, JT->getFirstLabel(),
921                                   EntryAddress - ArrayStart, &*BC.Ctx);
922 
923     return BranchType;
924   }
925 
926   LLVM_DEBUG(dbgs() << "BOLT-DEBUG: addressed memory is 0x"
927                     << Twine::utohexstr(ArrayStart) << '\n');
928 
929   ErrorOr<BinarySection &> Section = BC.getSectionForAddress(ArrayStart);
930   if (!Section) {
931     // No section - possibly an absolute address. Since we don't allow
932     // internal function addresses to escape the function scope - we
933     // consider it a tail call.
934     if (opts::Verbosity >= 1) {
935       BC.errs() << "BOLT-WARNING: no section for address 0x"
936                 << Twine::utohexstr(ArrayStart) << " referenced from function "
937                 << *this << '\n';
938     }
939     return IndirectBranchType::POSSIBLE_TAIL_CALL;
940   }
941   if (Section->isVirtual()) {
942     // The contents are filled at runtime.
943     return IndirectBranchType::POSSIBLE_TAIL_CALL;
944   }
945 
946   if (BranchType == IndirectBranchType::POSSIBLE_FIXED_BRANCH) {
947     ErrorOr<uint64_t> Value = BC.getPointerAtAddress(ArrayStart);
948     if (!Value)
949       return IndirectBranchType::UNKNOWN;
950 
951     if (BC.getSectionForAddress(ArrayStart)->isWritable())
952       return IndirectBranchType::UNKNOWN;
953 
954     BC.outs() << "BOLT-INFO: fixed indirect branch detected in " << *this
955               << " at 0x" << Twine::utohexstr(getAddress() + Offset)
956               << " referencing data at 0x" << Twine::utohexstr(ArrayStart)
957               << " the destination value is 0x" << Twine::utohexstr(*Value)
958               << '\n';
959 
960     TargetAddress = *Value;
961     return BranchType;
962   }
963 
964   // Check if there's already a jump table registered at this address.
965   MemoryContentsType MemType;
966   if (JumpTable *JT = BC.getJumpTableContainingAddress(ArrayStart)) {
967     switch (JT->Type) {
968     case JumpTable::JTT_NORMAL:
969       MemType = MemoryContentsType::POSSIBLE_JUMP_TABLE;
970       break;
971     case JumpTable::JTT_PIC:
972       MemType = MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE;
973       break;
974     }
975   } else {
976     MemType = BC.analyzeMemoryAt(ArrayStart, *this);
977   }
978 
979   // Check that jump table type in instruction pattern matches memory contents.
980   JumpTable::JumpTableType JTType;
981   if (BranchType == IndirectBranchType::POSSIBLE_PIC_JUMP_TABLE) {
982     if (MemType != MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE)
983       return IndirectBranchType::UNKNOWN;
984     JTType = JumpTable::JTT_PIC;
985   } else {
986     if (MemType == MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE)
987       return IndirectBranchType::UNKNOWN;
988 
989     if (MemType == MemoryContentsType::UNKNOWN)
990       return IndirectBranchType::POSSIBLE_TAIL_CALL;
991 
992     BranchType = IndirectBranchType::POSSIBLE_JUMP_TABLE;
993     JTType = JumpTable::JTT_NORMAL;
994   }
995 
996   // Convert the instruction into jump table branch.
997   const MCSymbol *JTLabel = BC.getOrCreateJumpTable(*this, ArrayStart, JTType);
998   BC.MIB->replaceMemOperandDisp(*MemLocInstr, JTLabel, BC.Ctx.get());
999   BC.MIB->setJumpTable(Instruction, ArrayStart, IndexRegNum);
1000 
1001   JTSites.emplace_back(Offset, ArrayStart);
1002 
1003   return BranchType;
1004 }
1005 
1006 MCSymbol *BinaryFunction::getOrCreateLocalLabel(uint64_t Address,
1007                                                 bool CreatePastEnd) {
1008   const uint64_t Offset = Address - getAddress();
1009 
1010   if ((Offset == getSize()) && CreatePastEnd)
1011     return getFunctionEndLabel();
1012 
1013   auto LI = Labels.find(Offset);
1014   if (LI != Labels.end())
1015     return LI->second;
1016 
1017   // For AArch64, check if this address is part of a constant island.
1018   if (BC.isAArch64()) {
1019     if (MCSymbol *IslandSym = getOrCreateIslandAccess(Address))
1020       return IslandSym;
1021   }
1022 
1023   MCSymbol *Label = BC.Ctx->createNamedTempSymbol();
1024   Labels[Offset] = Label;
1025 
1026   return Label;
1027 }
1028 
1029 ErrorOr<ArrayRef<uint8_t>> BinaryFunction::getData() const {
1030   BinarySection &Section = *getOriginSection();
1031   assert(Section.containsRange(getAddress(), getMaxSize()) &&
1032          "wrong section for function");
1033 
1034   if (!Section.isText() || Section.isVirtual() || !Section.getSize())
1035     return std::make_error_code(std::errc::bad_address);
1036 
1037   StringRef SectionContents = Section.getContents();
1038 
1039   assert(SectionContents.size() == Section.getSize() &&
1040          "section size mismatch");
1041 
1042   // Function offset from the section start.
1043   uint64_t Offset = getAddress() - Section.getAddress();
1044   auto *Bytes = reinterpret_cast<const uint8_t *>(SectionContents.data());
1045   return ArrayRef<uint8_t>(Bytes + Offset, getMaxSize());
1046 }
1047 
1048 size_t BinaryFunction::getSizeOfDataInCodeAt(uint64_t Offset) const {
1049   if (!Islands)
1050     return 0;
1051 
1052   if (!llvm::is_contained(Islands->DataOffsets, Offset))
1053     return 0;
1054 
1055   auto Iter = Islands->CodeOffsets.upper_bound(Offset);
1056   if (Iter != Islands->CodeOffsets.end())
1057     return *Iter - Offset;
1058   return getSize() - Offset;
1059 }
1060 
1061 bool BinaryFunction::isZeroPaddingAt(uint64_t Offset) const {
1062   ArrayRef<uint8_t> FunctionData = *getData();
1063   uint64_t EndOfCode = getSize();
1064   if (Islands) {
1065     auto Iter = Islands->DataOffsets.upper_bound(Offset);
1066     if (Iter != Islands->DataOffsets.end())
1067       EndOfCode = *Iter;
1068   }
1069   for (uint64_t I = Offset; I < EndOfCode; ++I)
1070     if (FunctionData[I] != 0)
1071       return false;
1072 
1073   return true;
1074 }
1075 
1076 Error BinaryFunction::handlePCRelOperand(MCInst &Instruction, uint64_t Address,
1077                                          uint64_t Size) {
1078   auto &MIB = BC.MIB;
1079   uint64_t TargetAddress = 0;
1080   if (!MIB->evaluateMemOperandTarget(Instruction, TargetAddress, Address,
1081                                      Size)) {
1082     std::string Msg;
1083     raw_string_ostream SS(Msg);
1084     SS << "BOLT-ERROR: PC-relative operand can't be evaluated:\n";
1085     BC.InstPrinter->printInst(&Instruction, 0, "", *BC.STI, SS);
1086     SS << '\n';
1087     Instruction.dump_pretty(SS, BC.InstPrinter.get());
1088     SS << '\n';
1089     SS << "BOLT-ERROR: cannot handle PC-relative operand at 0x"
1090        << Twine::utohexstr(Address) << ". Skipping function " << *this << ".\n";
1091     if (BC.HasRelocations)
1092       return createFatalBOLTError(Msg);
1093     IsSimple = false;
1094     return createNonFatalBOLTError(Msg);
1095   }
1096   if (TargetAddress == 0 && opts::Verbosity >= 1) {
1097     BC.outs() << "BOLT-INFO: PC-relative operand is zero in function " << *this
1098               << '\n';
1099   }
1100 
1101   const MCSymbol *TargetSymbol;
1102   uint64_t TargetOffset;
1103   std::tie(TargetSymbol, TargetOffset) =
1104       BC.handleAddressRef(TargetAddress, *this, /*IsPCRel*/ true);
1105 
1106   bool ReplaceSuccess = MIB->replaceMemOperandDisp(
1107       Instruction, TargetSymbol, static_cast<int64_t>(TargetOffset), &*BC.Ctx);
1108   (void)ReplaceSuccess;
1109   assert(ReplaceSuccess && "Failed to replace mem operand with symbol+off.");
1110   return Error::success();
1111 }
1112 
1113 MCSymbol *BinaryFunction::handleExternalReference(MCInst &Instruction,
1114                                                   uint64_t Size,
1115                                                   uint64_t Offset,
1116                                                   uint64_t TargetAddress,
1117                                                   bool &IsCall) {
1118   auto &MIB = BC.MIB;
1119 
1120   const uint64_t AbsoluteInstrAddr = getAddress() + Offset;
1121   BC.addInterproceduralReference(this, TargetAddress);
1122   if (opts::Verbosity >= 2 && !IsCall && Size == 2 && !BC.HasRelocations) {
1123     BC.errs() << "BOLT-WARNING: relaxed tail call detected at 0x"
1124               << Twine::utohexstr(AbsoluteInstrAddr) << " in function " << *this
1125               << ". Code size will be increased.\n";
1126   }
1127 
1128   assert(!MIB->isTailCall(Instruction) &&
1129          "synthetic tail call instruction found");
1130 
1131   // This is a call regardless of the opcode.
1132   // Assign proper opcode for tail calls, so that they could be
1133   // treated as calls.
1134   if (!IsCall) {
1135     if (!MIB->convertJmpToTailCall(Instruction)) {
1136       assert(MIB->isConditionalBranch(Instruction) &&
1137              "unknown tail call instruction");
1138       if (opts::Verbosity >= 2) {
1139         BC.errs() << "BOLT-WARNING: conditional tail call detected in "
1140                   << "function " << *this << " at 0x"
1141                   << Twine::utohexstr(AbsoluteInstrAddr) << ".\n";
1142       }
1143     }
1144     IsCall = true;
1145   }
1146 
1147   if (opts::Verbosity >= 2 && TargetAddress == 0) {
1148     // We actually see calls to address 0 in presence of weak
1149     // symbols originating from libraries. This code is never meant
1150     // to be executed.
1151     BC.outs() << "BOLT-INFO: Function " << *this
1152               << " has a call to address zero.\n";
1153   }
1154 
1155   return BC.getOrCreateGlobalSymbol(TargetAddress, "FUNCat");
1156 }
1157 
1158 void BinaryFunction::handleIndirectBranch(MCInst &Instruction, uint64_t Size,
1159                                           uint64_t Offset) {
1160   auto &MIB = BC.MIB;
1161   uint64_t IndirectTarget = 0;
1162   IndirectBranchType Result =
1163       processIndirectBranch(Instruction, Size, Offset, IndirectTarget);
1164   switch (Result) {
1165   default:
1166     llvm_unreachable("unexpected result");
1167   case IndirectBranchType::POSSIBLE_TAIL_CALL: {
1168     bool Result = MIB->convertJmpToTailCall(Instruction);
1169     (void)Result;
1170     assert(Result);
1171     break;
1172   }
1173   case IndirectBranchType::POSSIBLE_JUMP_TABLE:
1174   case IndirectBranchType::POSSIBLE_PIC_JUMP_TABLE:
1175   case IndirectBranchType::POSSIBLE_PIC_FIXED_BRANCH:
1176     if (opts::JumpTables == JTS_NONE)
1177       IsSimple = false;
1178     break;
1179   case IndirectBranchType::POSSIBLE_FIXED_BRANCH: {
1180     if (containsAddress(IndirectTarget)) {
1181       const MCSymbol *TargetSymbol = getOrCreateLocalLabel(IndirectTarget);
1182       Instruction.clear();
1183       MIB->createUncondBranch(Instruction, TargetSymbol, BC.Ctx.get());
1184       TakenBranches.emplace_back(Offset, IndirectTarget - getAddress());
1185       addEntryPointAtOffset(IndirectTarget - getAddress());
1186     } else {
1187       MIB->convertJmpToTailCall(Instruction);
1188       BC.addInterproceduralReference(this, IndirectTarget);
1189     }
1190     break;
1191   }
1192   case IndirectBranchType::UNKNOWN:
1193     // Keep processing. We'll do more checks and fixes in
1194     // postProcessIndirectBranches().
1195     UnknownIndirectBranchOffsets.emplace(Offset);
1196     break;
1197   }
1198 }
1199 
1200 void BinaryFunction::handleAArch64IndirectCall(MCInst &Instruction,
1201                                                const uint64_t Offset) {
1202   auto &MIB = BC.MIB;
1203   const uint64_t AbsoluteInstrAddr = getAddress() + Offset;
1204   MCInst *TargetHiBits, *TargetLowBits;
1205   uint64_t TargetAddress, Count;
1206   Count = MIB->matchLinkerVeneer(Instructions.begin(), Instructions.end(),
1207                                  AbsoluteInstrAddr, Instruction, TargetHiBits,
1208                                  TargetLowBits, TargetAddress);
1209   if (Count) {
1210     MIB->addAnnotation(Instruction, "AArch64Veneer", true);
1211     --Count;
1212     for (auto It = std::prev(Instructions.end()); Count != 0;
1213          It = std::prev(It), --Count) {
1214       MIB->addAnnotation(It->second, "AArch64Veneer", true);
1215     }
1216 
1217     BC.addAdrpAddRelocAArch64(*this, *TargetLowBits, *TargetHiBits,
1218                               TargetAddress);
1219   }
1220 }
1221 
1222 std::optional<MCInst>
1223 BinaryFunction::disassembleInstructionAtOffset(uint64_t Offset) const {
1224   assert(CurrentState == State::Empty && "Function should not be disassembled");
1225   assert(Offset < MaxSize && "Invalid offset");
1226   ErrorOr<ArrayRef<unsigned char>> FunctionData = getData();
1227   assert(FunctionData && "Cannot get function as data");
1228   MCInst Instr;
1229   uint64_t InstrSize = 0;
1230   const uint64_t InstrAddress = getAddress() + Offset;
1231   if (BC.DisAsm->getInstruction(Instr, InstrSize, FunctionData->slice(Offset),
1232                                 InstrAddress, nulls()))
1233     return Instr;
1234   return std::nullopt;
1235 }
1236 
1237 Error BinaryFunction::disassemble() {
1238   NamedRegionTimer T("disassemble", "Disassemble function", "buildfuncs",
1239                      "Build Binary Functions", opts::TimeBuild);
1240   ErrorOr<ArrayRef<uint8_t>> ErrorOrFunctionData = getData();
1241   assert(ErrorOrFunctionData && "function data is not available");
1242   ArrayRef<uint8_t> FunctionData = *ErrorOrFunctionData;
1243   assert(FunctionData.size() == getMaxSize() &&
1244          "function size does not match raw data size");
1245 
1246   auto &Ctx = BC.Ctx;
1247   auto &MIB = BC.MIB;
1248 
1249   BC.SymbolicDisAsm->setSymbolizer(MIB->createTargetSymbolizer(*this));
1250 
1251   // Insert a label at the beginning of the function. This will be our first
1252   // basic block.
1253   Labels[0] = Ctx->createNamedTempSymbol("BB0");
1254 
1255   // Map offsets in the function to a label that should always point to the
1256   // corresponding instruction. This is used for labels that shouldn't point to
1257   // the start of a basic block but always to a specific instruction. This is
1258   // used, for example, on RISC-V where %pcrel_lo relocations point to the
1259   // corresponding %pcrel_hi.
1260   LabelsMapType InstructionLabels;
1261 
1262   uint64_t Size = 0; // instruction size
1263   for (uint64_t Offset = 0; Offset < getSize(); Offset += Size) {
1264     MCInst Instruction;
1265     const uint64_t AbsoluteInstrAddr = getAddress() + Offset;
1266 
1267     // Check for data inside code and ignore it
1268     if (const size_t DataInCodeSize = getSizeOfDataInCodeAt(Offset)) {
1269       Size = DataInCodeSize;
1270       continue;
1271     }
1272 
1273     if (!BC.SymbolicDisAsm->getInstruction(Instruction, Size,
1274                                            FunctionData.slice(Offset),
1275                                            AbsoluteInstrAddr, nulls())) {
1276       // Functions with "soft" boundaries, e.g. coming from assembly source,
1277       // can have 0-byte padding at the end.
1278       if (isZeroPaddingAt(Offset))
1279         break;
1280 
1281       BC.errs()
1282           << "BOLT-WARNING: unable to disassemble instruction at offset 0x"
1283           << Twine::utohexstr(Offset) << " (address 0x"
1284           << Twine::utohexstr(AbsoluteInstrAddr) << ") in function " << *this
1285           << '\n';
1286       // Some AVX-512 instructions could not be disassembled at all.
1287       if (BC.HasRelocations && opts::TrapOnAVX512 && BC.isX86()) {
1288         setTrapOnEntry();
1289         BC.TrappedFunctions.push_back(this);
1290       } else {
1291         setIgnored();
1292       }
1293 
1294       break;
1295     }
1296 
1297     // Check integrity of LLVM assembler/disassembler.
1298     if (opts::CheckEncoding && !BC.MIB->isBranch(Instruction) &&
1299         !BC.MIB->isCall(Instruction) && !BC.MIB->isNoop(Instruction)) {
1300       if (!BC.validateInstructionEncoding(FunctionData.slice(Offset, Size))) {
1301         BC.errs() << "BOLT-WARNING: mismatching LLVM encoding detected in "
1302                   << "function " << *this << " for instruction :\n";
1303         BC.printInstruction(BC.errs(), Instruction, AbsoluteInstrAddr);
1304         BC.errs() << '\n';
1305       }
1306     }
1307 
1308     // Special handling for AVX-512 instructions.
1309     if (MIB->hasEVEXEncoding(Instruction)) {
1310       if (BC.HasRelocations && opts::TrapOnAVX512) {
1311         setTrapOnEntry();
1312         BC.TrappedFunctions.push_back(this);
1313         break;
1314       }
1315 
1316       if (!BC.validateInstructionEncoding(FunctionData.slice(Offset, Size))) {
1317         BC.errs() << "BOLT-WARNING: internal assembler/disassembler error "
1318                      "detected for AVX512 instruction:\n";
1319         BC.printInstruction(BC.errs(), Instruction, AbsoluteInstrAddr);
1320         BC.errs() << " in function " << *this << '\n';
1321         setIgnored();
1322         break;
1323       }
1324     }
1325 
1326     bool IsUnsupported = BC.MIB->isUnsupportedInstruction(Instruction);
1327     if (IsUnsupported)
1328       setIgnored();
1329 
1330     if (MIB->isBranch(Instruction) || MIB->isCall(Instruction)) {
1331       uint64_t TargetAddress = 0;
1332       if (MIB->evaluateBranch(Instruction, AbsoluteInstrAddr, Size,
1333                               TargetAddress)) {
1334         // Check if the target is within the same function. Otherwise it's
1335         // a call, possibly a tail call.
1336         //
1337         // If the target *is* the function address it could be either a branch
1338         // or a recursive call.
1339         bool IsCall = MIB->isCall(Instruction);
1340         const bool IsCondBranch = MIB->isConditionalBranch(Instruction);
1341         MCSymbol *TargetSymbol = nullptr;
1342 
1343         if (IsUnsupported)
1344           if (auto *TargetFunc =
1345                   BC.getBinaryFunctionContainingAddress(TargetAddress))
1346             TargetFunc->setIgnored();
1347 
1348         if (IsCall && TargetAddress == getAddress()) {
1349           // A recursive call. Calls to internal blocks are handled by
1350           // ValidateInternalCalls pass.
1351           TargetSymbol = getSymbol();
1352         }
1353 
1354         if (!TargetSymbol) {
1355           // Create either local label or external symbol.
1356           if (containsAddress(TargetAddress)) {
1357             TargetSymbol = getOrCreateLocalLabel(TargetAddress);
1358           } else {
1359             if (TargetAddress == getAddress() + getSize() &&
1360                 TargetAddress < getAddress() + getMaxSize() &&
1361                 !(BC.isAArch64() &&
1362                   BC.handleAArch64Veneer(TargetAddress, /*MatchOnly*/ true))) {
1363               // Result of __builtin_unreachable().
1364               LLVM_DEBUG(dbgs() << "BOLT-DEBUG: jump past end detected at 0x"
1365                                 << Twine::utohexstr(AbsoluteInstrAddr)
1366                                 << " in function " << *this
1367                                 << " : replacing with nop.\n");
1368               BC.MIB->createNoop(Instruction);
1369               if (IsCondBranch) {
1370                 // Register branch offset for profile validation.
1371                 IgnoredBranches.emplace_back(Offset, Offset + Size);
1372               }
1373               goto add_instruction;
1374             }
1375             // May update Instruction and IsCall
1376             TargetSymbol = handleExternalReference(Instruction, Size, Offset,
1377                                                    TargetAddress, IsCall);
1378           }
1379         }
1380 
1381         if (!IsCall) {
1382           // Add taken branch info.
1383           TakenBranches.emplace_back(Offset, TargetAddress - getAddress());
1384         }
1385         BC.MIB->replaceBranchTarget(Instruction, TargetSymbol, &*Ctx);
1386 
1387         // Mark CTC.
1388         if (IsCondBranch && IsCall)
1389           MIB->setConditionalTailCall(Instruction, TargetAddress);
1390       } else {
1391         // Could not evaluate branch. Should be an indirect call or an
1392         // indirect branch. Bail out on the latter case.
1393         if (MIB->isIndirectBranch(Instruction))
1394           handleIndirectBranch(Instruction, Size, Offset);
1395         // Indirect call. We only need to fix it if the operand is RIP-relative.
1396         if (IsSimple && MIB->hasPCRelOperand(Instruction)) {
1397           if (auto NewE = handleErrors(
1398                   handlePCRelOperand(Instruction, AbsoluteInstrAddr, Size),
1399                   [&](const BOLTError &E) -> Error {
1400                     if (E.isFatal())
1401                       return Error(std::make_unique<BOLTError>(std::move(E)));
1402                     if (!E.getMessage().empty())
1403                       E.log(BC.errs());
1404                     return Error::success();
1405                   })) {
1406             return Error(std::move(NewE));
1407           }
1408         }
1409 
1410         if (BC.isAArch64())
1411           handleAArch64IndirectCall(Instruction, Offset);
1412       }
1413     } else if (BC.isAArch64() || BC.isRISCV()) {
1414       // Check if there's a relocation associated with this instruction.
1415       bool UsedReloc = false;
1416       for (auto Itr = Relocations.lower_bound(Offset),
1417                 ItrE = Relocations.lower_bound(Offset + Size);
1418            Itr != ItrE; ++Itr) {
1419         const Relocation &Relocation = Itr->second;
1420         MCSymbol *Symbol = Relocation.Symbol;
1421 
1422         if (Relocation::isInstructionReference(Relocation.Type)) {
1423           uint64_t RefOffset = Relocation.Value - getAddress();
1424           LabelsMapType::iterator LI = InstructionLabels.find(RefOffset);
1425 
1426           if (LI == InstructionLabels.end()) {
1427             Symbol = BC.Ctx->createNamedTempSymbol();
1428             InstructionLabels.emplace(RefOffset, Symbol);
1429           } else {
1430             Symbol = LI->second;
1431           }
1432         }
1433 
1434         int64_t Value = Relocation.Value;
1435         const bool Result = BC.MIB->replaceImmWithSymbolRef(
1436             Instruction, Symbol, Relocation.Addend, Ctx.get(), Value,
1437             Relocation.Type);
1438         (void)Result;
1439         assert(Result && "cannot replace immediate with relocation");
1440 
1441         // For aarch64, if we replaced an immediate with a symbol from a
1442         // relocation, we mark it so we do not try to further process a
1443         // pc-relative operand. All we need is the symbol.
1444         UsedReloc = true;
1445       }
1446 
1447       if (!BC.isRISCV() && MIB->hasPCRelOperand(Instruction) && !UsedReloc) {
1448         if (auto NewE = handleErrors(
1449                 handlePCRelOperand(Instruction, AbsoluteInstrAddr, Size),
1450                 [&](const BOLTError &E) -> Error {
1451                   if (E.isFatal())
1452                     return Error(std::make_unique<BOLTError>(std::move(E)));
1453                   if (!E.getMessage().empty())
1454                     E.log(BC.errs());
1455                   return Error::success();
1456                 }))
1457           return Error(std::move(NewE));
1458       }
1459     }
1460 
1461 add_instruction:
1462     if (getDWARFLineTable()) {
1463       Instruction.setLoc(findDebugLineInformationForInstructionAt(
1464           AbsoluteInstrAddr, getDWARFUnit(), getDWARFLineTable()));
1465     }
1466 
1467     // Record offset of the instruction for profile matching.
1468     if (BC.keepOffsetForInstruction(Instruction))
1469       MIB->setOffset(Instruction, static_cast<uint32_t>(Offset));
1470 
1471     if (BC.isX86() && BC.MIB->isNoop(Instruction)) {
1472       // NOTE: disassembly loses the correct size information for noops on x86.
1473       //       E.g. nopw 0x0(%rax,%rax,1) is 9 bytes, but re-encoded it's only
1474       //       5 bytes. Preserve the size info using annotations.
1475       MIB->setSize(Instruction, Size);
1476     }
1477 
1478     addInstruction(Offset, std::move(Instruction));
1479   }
1480 
1481   for (auto [Offset, Label] : InstructionLabels) {
1482     InstrMapType::iterator II = Instructions.find(Offset);
1483     assert(II != Instructions.end() && "reference to non-existing instruction");
1484 
1485     BC.MIB->setInstLabel(II->second, Label);
1486   }
1487 
1488   // Reset symbolizer for the disassembler.
1489   BC.SymbolicDisAsm->setSymbolizer(nullptr);
1490 
1491   if (uint64_t Offset = getFirstInstructionOffset())
1492     Labels[Offset] = BC.Ctx->createNamedTempSymbol();
1493 
1494   clearList(Relocations);
1495 
1496   if (!IsSimple) {
1497     clearList(Instructions);
1498     return createNonFatalBOLTError("");
1499   }
1500 
1501   updateState(State::Disassembled);
1502 
1503   return Error::success();
1504 }
1505 
1506 MCSymbol *BinaryFunction::registerBranch(uint64_t Src, uint64_t Dst) {
1507   assert(CurrentState == State::Disassembled &&
1508          "Cannot register branch unless function is in disassembled state.");
1509   assert(containsAddress(Src) && containsAddress(Dst) &&
1510          "Cannot register external branch.");
1511   MCSymbol *Target = getOrCreateLocalLabel(Dst);
1512   TakenBranches.emplace_back(Src - getAddress(), Dst - getAddress());
1513   return Target;
1514 }
1515 
1516 bool BinaryFunction::scanExternalRefs() {
1517   bool Success = true;
1518   bool DisassemblyFailed = false;
1519 
1520   // Ignore pseudo functions.
1521   if (isPseudo())
1522     return Success;
1523 
1524   if (opts::NoScan) {
1525     clearList(Relocations);
1526     clearList(ExternallyReferencedOffsets);
1527 
1528     return false;
1529   }
1530 
1531   // List of external references for this function.
1532   std::vector<Relocation> FunctionRelocations;
1533 
1534   static BinaryContext::IndependentCodeEmitter Emitter =
1535       BC.createIndependentMCCodeEmitter();
1536 
1537   ErrorOr<ArrayRef<uint8_t>> ErrorOrFunctionData = getData();
1538   assert(ErrorOrFunctionData && "function data is not available");
1539   ArrayRef<uint8_t> FunctionData = *ErrorOrFunctionData;
1540   assert(FunctionData.size() == getMaxSize() &&
1541          "function size does not match raw data size");
1542 
1543   BC.SymbolicDisAsm->setSymbolizer(
1544       BC.MIB->createTargetSymbolizer(*this, /*CreateSymbols*/ false));
1545 
1546   // Disassemble contents of the function. Detect code entry points and create
1547   // relocations for references to code that will be moved.
1548   uint64_t Size = 0; // instruction size
1549   for (uint64_t Offset = 0; Offset < getSize(); Offset += Size) {
1550     // Check for data inside code and ignore it
1551     if (const size_t DataInCodeSize = getSizeOfDataInCodeAt(Offset)) {
1552       Size = DataInCodeSize;
1553       continue;
1554     }
1555 
1556     const uint64_t AbsoluteInstrAddr = getAddress() + Offset;
1557     MCInst Instruction;
1558     if (!BC.SymbolicDisAsm->getInstruction(Instruction, Size,
1559                                            FunctionData.slice(Offset),
1560                                            AbsoluteInstrAddr, nulls())) {
1561       if (opts::Verbosity >= 1 && !isZeroPaddingAt(Offset)) {
1562         BC.errs()
1563             << "BOLT-WARNING: unable to disassemble instruction at offset 0x"
1564             << Twine::utohexstr(Offset) << " (address 0x"
1565             << Twine::utohexstr(AbsoluteInstrAddr) << ") in function " << *this
1566             << '\n';
1567       }
1568       Success = false;
1569       DisassemblyFailed = true;
1570       break;
1571     }
1572 
1573     // Return true if we can skip handling the Target function reference.
1574     auto ignoreFunctionRef = [&](const BinaryFunction &Target) {
1575       if (&Target == this)
1576         return true;
1577 
1578       // Note that later we may decide not to emit Target function. In that
1579       // case, we conservatively create references that will be ignored or
1580       // resolved to the same function.
1581       if (!BC.shouldEmit(Target))
1582         return true;
1583 
1584       return false;
1585     };
1586 
1587     // Return true if we can ignore reference to the symbol.
1588     auto ignoreReference = [&](const MCSymbol *TargetSymbol) {
1589       if (!TargetSymbol)
1590         return true;
1591 
1592       if (BC.forceSymbolRelocations(TargetSymbol->getName()))
1593         return false;
1594 
1595       BinaryFunction *TargetFunction = BC.getFunctionForSymbol(TargetSymbol);
1596       if (!TargetFunction)
1597         return true;
1598 
1599       return ignoreFunctionRef(*TargetFunction);
1600     };
1601 
1602     // Handle calls and branches separately as symbolization doesn't work for
1603     // them yet.
1604     MCSymbol *BranchTargetSymbol = nullptr;
1605     if (BC.MIB->isCall(Instruction) || BC.MIB->isBranch(Instruction)) {
1606       uint64_t TargetAddress = 0;
1607       BC.MIB->evaluateBranch(Instruction, AbsoluteInstrAddr, Size,
1608                              TargetAddress);
1609 
1610       // Create an entry point at reference address if needed.
1611       BinaryFunction *TargetFunction =
1612           BC.getBinaryFunctionContainingAddress(TargetAddress);
1613 
1614       if (!TargetFunction || ignoreFunctionRef(*TargetFunction))
1615         continue;
1616 
1617       const uint64_t FunctionOffset =
1618           TargetAddress - TargetFunction->getAddress();
1619       BranchTargetSymbol =
1620           FunctionOffset ? TargetFunction->addEntryPointAtOffset(FunctionOffset)
1621                          : TargetFunction->getSymbol();
1622     }
1623 
1624     // Can't find more references. Not creating relocations since we are not
1625     // moving code.
1626     if (!BC.HasRelocations)
1627       continue;
1628 
1629     if (BranchTargetSymbol) {
1630       BC.MIB->replaceBranchTarget(Instruction, BranchTargetSymbol,
1631                                   Emitter.LocalCtx.get());
1632     } else if (!llvm::any_of(Instruction,
1633                              [](const MCOperand &Op) { return Op.isExpr(); })) {
1634       // Skip assembly if the instruction may not have any symbolic operands.
1635       continue;
1636     }
1637 
1638     // Emit the instruction using temp emitter and generate relocations.
1639     SmallString<256> Code;
1640     SmallVector<MCFixup, 4> Fixups;
1641     Emitter.MCE->encodeInstruction(Instruction, Code, Fixups, *BC.STI);
1642 
1643     // Create relocation for every fixup.
1644     for (const MCFixup &Fixup : Fixups) {
1645       std::optional<Relocation> Rel = BC.MIB->createRelocation(Fixup, *BC.MAB);
1646       if (!Rel) {
1647         Success = false;
1648         continue;
1649       }
1650 
1651       if (ignoreReference(Rel->Symbol))
1652         continue;
1653 
1654       if (Relocation::getSizeForType(Rel->Type) < 4) {
1655         // If the instruction uses a short form, then we might not be able
1656         // to handle the rewrite without relaxation, and hence cannot reliably
1657         // create an external reference relocation.
1658         Success = false;
1659         continue;
1660       }
1661       Rel->Offset += getAddress() - getOriginSection()->getAddress() + Offset;
1662       FunctionRelocations.push_back(*Rel);
1663     }
1664 
1665     if (!Success)
1666       break;
1667   }
1668 
1669   // Reset symbolizer for the disassembler.
1670   BC.SymbolicDisAsm->setSymbolizer(nullptr);
1671 
1672   // Add relocations unless disassembly failed for this function.
1673   if (!DisassemblyFailed)
1674     for (Relocation &Rel : FunctionRelocations)
1675       getOriginSection()->addPendingRelocation(Rel);
1676 
1677   // Inform BinaryContext that this function symbols will not be defined and
1678   // relocations should not be created against them.
1679   if (BC.HasRelocations) {
1680     for (std::pair<const uint32_t, MCSymbol *> &LI : Labels)
1681       BC.UndefinedSymbols.insert(LI.second);
1682     for (MCSymbol *const EndLabel : FunctionEndLabels)
1683       if (EndLabel)
1684         BC.UndefinedSymbols.insert(EndLabel);
1685   }
1686 
1687   clearList(Relocations);
1688   clearList(ExternallyReferencedOffsets);
1689 
1690   if (Success && BC.HasRelocations)
1691     HasExternalRefRelocations = true;
1692 
1693   if (opts::Verbosity >= 1 && !Success)
1694     BC.outs() << "BOLT-INFO: failed to scan refs for  " << *this << '\n';
1695 
1696   return Success;
1697 }
1698 
1699 void BinaryFunction::postProcessEntryPoints() {
1700   if (!isSimple())
1701     return;
1702 
1703   for (auto &KV : Labels) {
1704     MCSymbol *Label = KV.second;
1705     if (!getSecondaryEntryPointSymbol(Label))
1706       continue;
1707 
1708     // In non-relocation mode there's potentially an external undetectable
1709     // reference to the entry point and hence we cannot move this entry
1710     // point. Optimizing without moving could be difficult.
1711     // In BAT mode, register any known entry points for CFG construction.
1712     if (!BC.HasRelocations && !BC.HasBATSection)
1713       setSimple(false);
1714 
1715     const uint32_t Offset = KV.first;
1716 
1717     // If we are at Offset 0 and there is no instruction associated with it,
1718     // this means this is an empty function. Just ignore. If we find an
1719     // instruction at this offset, this entry point is valid.
1720     if (!Offset || getInstructionAtOffset(Offset))
1721       continue;
1722 
1723     // On AArch64 there are legitimate reasons to have references past the
1724     // end of the function, e.g. jump tables.
1725     if (BC.isAArch64() && Offset == getSize())
1726       continue;
1727 
1728     BC.errs() << "BOLT-WARNING: reference in the middle of instruction "
1729                  "detected in function "
1730               << *this << " at offset 0x" << Twine::utohexstr(Offset) << '\n';
1731     if (BC.HasRelocations)
1732       setIgnored();
1733     setSimple(false);
1734     return;
1735   }
1736 }
1737 
1738 void BinaryFunction::postProcessJumpTables() {
1739   // Create labels for all entries.
1740   for (auto &JTI : JumpTables) {
1741     JumpTable &JT = *JTI.second;
1742     if (JT.Type == JumpTable::JTT_PIC && opts::JumpTables == JTS_BASIC) {
1743       opts::JumpTables = JTS_MOVE;
1744       BC.outs() << "BOLT-INFO: forcing -jump-tables=move as PIC jump table was "
1745                    "detected in function "
1746                 << *this << '\n';
1747     }
1748     const uint64_t BDSize =
1749         BC.getBinaryDataAtAddress(JT.getAddress())->getSize();
1750     if (!BDSize) {
1751       BC.setBinaryDataSize(JT.getAddress(), JT.getSize());
1752     } else {
1753       assert(BDSize >= JT.getSize() &&
1754              "jump table cannot be larger than the containing object");
1755     }
1756     if (!JT.Entries.empty())
1757       continue;
1758 
1759     bool HasOneParent = (JT.Parents.size() == 1);
1760     for (uint64_t EntryAddress : JT.EntriesAsAddress) {
1761       // builtin_unreachable does not belong to any function
1762       // Need to handle separately
1763       bool IsBuiltinUnreachable =
1764           llvm::any_of(JT.Parents, [&](const BinaryFunction *Parent) {
1765             return EntryAddress == Parent->getAddress() + Parent->getSize();
1766           });
1767       if (IsBuiltinUnreachable) {
1768         MCSymbol *Label = getOrCreateLocalLabel(EntryAddress, true);
1769         JT.Entries.push_back(Label);
1770         continue;
1771       }
1772       // Create a local label for targets that cannot be reached by other
1773       // fragments. Otherwise, create a secondary entry point in the target
1774       // function.
1775       BinaryFunction *TargetBF =
1776           BC.getBinaryFunctionContainingAddress(EntryAddress);
1777       MCSymbol *Label;
1778       if (HasOneParent && TargetBF == this) {
1779         Label = getOrCreateLocalLabel(EntryAddress, true);
1780       } else {
1781         const uint64_t Offset = EntryAddress - TargetBF->getAddress();
1782         Label = Offset ? TargetBF->addEntryPointAtOffset(Offset)
1783                        : TargetBF->getSymbol();
1784       }
1785       JT.Entries.push_back(Label);
1786     }
1787   }
1788 
1789   // Add TakenBranches from JumpTables.
1790   //
1791   // We want to do it after initial processing since we don't know jump tables'
1792   // boundaries until we process them all.
1793   for (auto &JTSite : JTSites) {
1794     const uint64_t JTSiteOffset = JTSite.first;
1795     const uint64_t JTAddress = JTSite.second;
1796     const JumpTable *JT = getJumpTableContainingAddress(JTAddress);
1797     assert(JT && "cannot find jump table for address");
1798 
1799     uint64_t EntryOffset = JTAddress - JT->getAddress();
1800     while (EntryOffset < JT->getSize()) {
1801       uint64_t EntryAddress = JT->EntriesAsAddress[EntryOffset / JT->EntrySize];
1802       uint64_t TargetOffset = EntryAddress - getAddress();
1803       if (TargetOffset < getSize()) {
1804         TakenBranches.emplace_back(JTSiteOffset, TargetOffset);
1805 
1806         if (opts::StrictMode)
1807           registerReferencedOffset(TargetOffset);
1808       }
1809 
1810       EntryOffset += JT->EntrySize;
1811 
1812       // A label at the next entry means the end of this jump table.
1813       if (JT->Labels.count(EntryOffset))
1814         break;
1815     }
1816   }
1817   clearList(JTSites);
1818 
1819   // Conservatively populate all possible destinations for unknown indirect
1820   // branches.
1821   if (opts::StrictMode && hasInternalReference()) {
1822     for (uint64_t Offset : UnknownIndirectBranchOffsets) {
1823       for (uint64_t PossibleDestination : ExternallyReferencedOffsets) {
1824         // Ignore __builtin_unreachable().
1825         if (PossibleDestination == getSize())
1826           continue;
1827         TakenBranches.emplace_back(Offset, PossibleDestination);
1828       }
1829     }
1830   }
1831 }
1832 
1833 bool BinaryFunction::validateExternallyReferencedOffsets() {
1834   SmallPtrSet<MCSymbol *, 4> JTTargets;
1835   for (const JumpTable *JT : llvm::make_second_range(JumpTables))
1836     JTTargets.insert(JT->Entries.begin(), JT->Entries.end());
1837 
1838   bool HasUnclaimedReference = false;
1839   for (uint64_t Destination : ExternallyReferencedOffsets) {
1840     // Ignore __builtin_unreachable().
1841     if (Destination == getSize())
1842       continue;
1843     // Ignore constant islands
1844     if (isInConstantIsland(Destination + getAddress()))
1845       continue;
1846 
1847     if (BinaryBasicBlock *BB = getBasicBlockAtOffset(Destination)) {
1848       // Check if the externally referenced offset is a recognized jump table
1849       // target.
1850       if (JTTargets.contains(BB->getLabel()))
1851         continue;
1852 
1853       if (opts::Verbosity >= 1) {
1854         BC.errs() << "BOLT-WARNING: unclaimed data to code reference (possibly "
1855                   << "an unrecognized jump table entry) to " << BB->getName()
1856                   << " in " << *this << "\n";
1857       }
1858       auto L = BC.scopeLock();
1859       addEntryPoint(*BB);
1860     } else {
1861       BC.errs() << "BOLT-WARNING: unknown data to code reference to offset "
1862                 << Twine::utohexstr(Destination) << " in " << *this << "\n";
1863       setIgnored();
1864     }
1865     HasUnclaimedReference = true;
1866   }
1867   return !HasUnclaimedReference;
1868 }
1869 
1870 bool BinaryFunction::postProcessIndirectBranches(
1871     MCPlusBuilder::AllocatorIdTy AllocId) {
1872   auto addUnknownControlFlow = [&](BinaryBasicBlock &BB) {
1873     LLVM_DEBUG(dbgs() << "BOLT-DEBUG: adding unknown control flow in " << *this
1874                       << " for " << BB.getName() << "\n");
1875     HasUnknownControlFlow = true;
1876     BB.removeAllSuccessors();
1877     for (uint64_t PossibleDestination : ExternallyReferencedOffsets)
1878       if (BinaryBasicBlock *SuccBB = getBasicBlockAtOffset(PossibleDestination))
1879         BB.addSuccessor(SuccBB);
1880   };
1881 
1882   uint64_t NumIndirectJumps = 0;
1883   MCInst *LastIndirectJump = nullptr;
1884   BinaryBasicBlock *LastIndirectJumpBB = nullptr;
1885   uint64_t LastJT = 0;
1886   uint16_t LastJTIndexReg = BC.MIB->getNoRegister();
1887   for (BinaryBasicBlock &BB : blocks()) {
1888     for (BinaryBasicBlock::iterator II = BB.begin(); II != BB.end(); ++II) {
1889       MCInst &Instr = *II;
1890       if (!BC.MIB->isIndirectBranch(Instr))
1891         continue;
1892 
1893       // If there's an indirect branch in a single-block function -
1894       // it must be a tail call.
1895       if (BasicBlocks.size() == 1) {
1896         BC.MIB->convertJmpToTailCall(Instr);
1897         return true;
1898       }
1899 
1900       ++NumIndirectJumps;
1901 
1902       if (opts::StrictMode && !hasInternalReference()) {
1903         BC.MIB->convertJmpToTailCall(Instr);
1904         break;
1905       }
1906 
1907       // Validate the tail call or jump table assumptions now that we know
1908       // basic block boundaries.
1909       if (BC.MIB->isTailCall(Instr) || BC.MIB->getJumpTable(Instr)) {
1910         const unsigned PtrSize = BC.AsmInfo->getCodePointerSize();
1911         MCInst *MemLocInstr;
1912         unsigned BaseRegNum, IndexRegNum;
1913         int64_t DispValue;
1914         const MCExpr *DispExpr;
1915         MCInst *PCRelBaseInstr;
1916         MCInst *FixedEntryLoadInstr;
1917         IndirectBranchType Type = BC.MIB->analyzeIndirectBranch(
1918             Instr, BB.begin(), II, PtrSize, MemLocInstr, BaseRegNum,
1919             IndexRegNum, DispValue, DispExpr, PCRelBaseInstr,
1920             FixedEntryLoadInstr);
1921         if (Type != IndirectBranchType::UNKNOWN || MemLocInstr != nullptr)
1922           continue;
1923 
1924         if (!opts::StrictMode)
1925           return false;
1926 
1927         if (BC.MIB->isTailCall(Instr)) {
1928           BC.MIB->convertTailCallToJmp(Instr);
1929         } else {
1930           LastIndirectJump = &Instr;
1931           LastIndirectJumpBB = &BB;
1932           LastJT = BC.MIB->getJumpTable(Instr);
1933           LastJTIndexReg = BC.MIB->getJumpTableIndexReg(Instr);
1934           BC.MIB->unsetJumpTable(Instr);
1935 
1936           JumpTable *JT = BC.getJumpTableContainingAddress(LastJT);
1937           if (JT->Type == JumpTable::JTT_NORMAL) {
1938             // Invalidating the jump table may also invalidate other jump table
1939             // boundaries. Until we have/need a support for this, mark the
1940             // function as non-simple.
1941             LLVM_DEBUG(dbgs() << "BOLT-DEBUG: rejected jump table reference"
1942                               << JT->getName() << " in " << *this << '\n');
1943             return false;
1944           }
1945         }
1946 
1947         addUnknownControlFlow(BB);
1948         continue;
1949       }
1950 
1951       // If this block contains an epilogue code and has an indirect branch,
1952       // then most likely it's a tail call. Otherwise, we cannot tell for sure
1953       // what it is and conservatively reject the function's CFG.
1954       bool IsEpilogue = llvm::any_of(BB, [&](const MCInst &Instr) {
1955         return BC.MIB->isLeave(Instr) || BC.MIB->isPop(Instr);
1956       });
1957       if (IsEpilogue) {
1958         BC.MIB->convertJmpToTailCall(Instr);
1959         BB.removeAllSuccessors();
1960         continue;
1961       }
1962 
1963       if (opts::Verbosity >= 2) {
1964         BC.outs() << "BOLT-INFO: rejected potential indirect tail call in "
1965                   << "function " << *this << " in basic block " << BB.getName()
1966                   << ".\n";
1967         LLVM_DEBUG(BC.printInstructions(dbgs(), BB.begin(), BB.end(),
1968                                         BB.getOffset(), this, true));
1969       }
1970 
1971       if (!opts::StrictMode)
1972         return false;
1973 
1974       addUnknownControlFlow(BB);
1975     }
1976   }
1977 
1978   if (HasInternalLabelReference)
1979     return false;
1980 
1981   // If there's only one jump table, and one indirect jump, and no other
1982   // references, then we should be able to derive the jump table even if we
1983   // fail to match the pattern.
1984   if (HasUnknownControlFlow && NumIndirectJumps == 1 &&
1985       JumpTables.size() == 1 && LastIndirectJump &&
1986       !BC.getJumpTableContainingAddress(LastJT)->IsSplit) {
1987     LLVM_DEBUG(dbgs() << "BOLT-DEBUG: unsetting unknown control flow in "
1988                       << *this << '\n');
1989     BC.MIB->setJumpTable(*LastIndirectJump, LastJT, LastJTIndexReg, AllocId);
1990     HasUnknownControlFlow = false;
1991 
1992     LastIndirectJumpBB->updateJumpTableSuccessors();
1993   }
1994 
1995   // Validate that all data references to function offsets are claimed by
1996   // recognized jump tables. Register externally referenced blocks as entry
1997   // points.
1998   if (!opts::StrictMode && hasInternalReference()) {
1999     if (!validateExternallyReferencedOffsets())
2000       return false;
2001   }
2002 
2003   if (HasUnknownControlFlow && !BC.HasRelocations)
2004     return false;
2005 
2006   return true;
2007 }
2008 
2009 void BinaryFunction::recomputeLandingPads() {
2010   updateBBIndices(0);
2011 
2012   for (BinaryBasicBlock *BB : BasicBlocks) {
2013     BB->LandingPads.clear();
2014     BB->Throwers.clear();
2015   }
2016 
2017   for (BinaryBasicBlock *BB : BasicBlocks) {
2018     std::unordered_set<const BinaryBasicBlock *> BBLandingPads;
2019     for (MCInst &Instr : *BB) {
2020       if (!BC.MIB->isInvoke(Instr))
2021         continue;
2022 
2023       const std::optional<MCPlus::MCLandingPad> EHInfo =
2024           BC.MIB->getEHInfo(Instr);
2025       if (!EHInfo || !EHInfo->first)
2026         continue;
2027 
2028       BinaryBasicBlock *LPBlock = getBasicBlockForLabel(EHInfo->first);
2029       if (!BBLandingPads.count(LPBlock)) {
2030         BBLandingPads.insert(LPBlock);
2031         BB->LandingPads.emplace_back(LPBlock);
2032         LPBlock->Throwers.emplace_back(BB);
2033       }
2034     }
2035   }
2036 }
2037 
2038 Error BinaryFunction::buildCFG(MCPlusBuilder::AllocatorIdTy AllocatorId) {
2039   auto &MIB = BC.MIB;
2040 
2041   if (!isSimple()) {
2042     assert(!BC.HasRelocations &&
2043            "cannot process file with non-simple function in relocs mode");
2044     return createNonFatalBOLTError("");
2045   }
2046 
2047   if (CurrentState != State::Disassembled)
2048     return createNonFatalBOLTError("");
2049 
2050   assert(BasicBlocks.empty() && "basic block list should be empty");
2051   assert((Labels.find(getFirstInstructionOffset()) != Labels.end()) &&
2052          "first instruction should always have a label");
2053 
2054   // Create basic blocks in the original layout order:
2055   //
2056   //  * Every instruction with associated label marks
2057   //    the beginning of a basic block.
2058   //  * Conditional instruction marks the end of a basic block,
2059   //    except when the following instruction is an
2060   //    unconditional branch, and the unconditional branch is not
2061   //    a destination of another branch. In the latter case, the
2062   //    basic block will consist of a single unconditional branch
2063   //    (missed "double-jump" optimization).
2064   //
2065   // Created basic blocks are sorted in layout order since they are
2066   // created in the same order as instructions, and instructions are
2067   // sorted by offsets.
2068   BinaryBasicBlock *InsertBB = nullptr;
2069   BinaryBasicBlock *PrevBB = nullptr;
2070   bool IsLastInstrNop = false;
2071   // Offset of the last non-nop instruction.
2072   uint64_t LastInstrOffset = 0;
2073 
2074   auto addCFIPlaceholders = [this](uint64_t CFIOffset,
2075                                    BinaryBasicBlock *InsertBB) {
2076     for (auto FI = OffsetToCFI.lower_bound(CFIOffset),
2077               FE = OffsetToCFI.upper_bound(CFIOffset);
2078          FI != FE; ++FI) {
2079       addCFIPseudo(InsertBB, InsertBB->end(), FI->second);
2080     }
2081   };
2082 
2083   // For profiling purposes we need to save the offset of the last instruction
2084   // in the basic block.
2085   // NOTE: nops always have an Offset annotation. Annotate the last non-nop as
2086   //       older profiles ignored nops.
2087   auto updateOffset = [&](uint64_t Offset) {
2088     assert(PrevBB && PrevBB != InsertBB && "invalid previous block");
2089     MCInst *LastNonNop = nullptr;
2090     for (BinaryBasicBlock::reverse_iterator RII = PrevBB->getLastNonPseudo(),
2091                                             E = PrevBB->rend();
2092          RII != E; ++RII) {
2093       if (!BC.MIB->isPseudo(*RII) && !BC.MIB->isNoop(*RII)) {
2094         LastNonNop = &*RII;
2095         break;
2096       }
2097     }
2098     if (LastNonNop && !MIB->getOffset(*LastNonNop))
2099       MIB->setOffset(*LastNonNop, static_cast<uint32_t>(Offset));
2100   };
2101 
2102   for (auto I = Instructions.begin(), E = Instructions.end(); I != E; ++I) {
2103     const uint32_t Offset = I->first;
2104     MCInst &Instr = I->second;
2105 
2106     auto LI = Labels.find(Offset);
2107     if (LI != Labels.end()) {
2108       // Always create new BB at branch destination.
2109       PrevBB = InsertBB ? InsertBB : PrevBB;
2110       InsertBB = addBasicBlockAt(LI->first, LI->second);
2111       if (opts::PreserveBlocksAlignment && IsLastInstrNop)
2112         InsertBB->setDerivedAlignment();
2113 
2114       if (PrevBB)
2115         updateOffset(LastInstrOffset);
2116     }
2117 
2118     // Mark all nops with Offset for profile tracking purposes.
2119     if (MIB->isNoop(Instr) && !MIB->getOffset(Instr)) {
2120       // If "Offset" annotation is not present, set it and mark the nop for
2121       // deletion.
2122       MIB->setOffset(Instr, static_cast<uint32_t>(Offset));
2123       // Annotate ordinary nops, so we can safely delete them if required.
2124       MIB->addAnnotation(Instr, "NOP", static_cast<uint32_t>(1), AllocatorId);
2125     }
2126 
2127     if (!InsertBB) {
2128       // It must be a fallthrough or unreachable code. Create a new block unless
2129       // we see an unconditional branch following a conditional one. The latter
2130       // should not be a conditional tail call.
2131       assert(PrevBB && "no previous basic block for a fall through");
2132       MCInst *PrevInstr = PrevBB->getLastNonPseudoInstr();
2133       assert(PrevInstr && "no previous instruction for a fall through");
2134       if (MIB->isUnconditionalBranch(Instr) &&
2135           !MIB->isIndirectBranch(*PrevInstr) &&
2136           !MIB->isUnconditionalBranch(*PrevInstr) &&
2137           !MIB->getConditionalTailCall(*PrevInstr) &&
2138           !MIB->isReturn(*PrevInstr)) {
2139         // Temporarily restore inserter basic block.
2140         InsertBB = PrevBB;
2141       } else {
2142         MCSymbol *Label;
2143         {
2144           auto L = BC.scopeLock();
2145           Label = BC.Ctx->createNamedTempSymbol("FT");
2146         }
2147         InsertBB = addBasicBlockAt(Offset, Label);
2148         if (opts::PreserveBlocksAlignment && IsLastInstrNop)
2149           InsertBB->setDerivedAlignment();
2150         updateOffset(LastInstrOffset);
2151       }
2152     }
2153     if (Offset == getFirstInstructionOffset()) {
2154       // Add associated CFI pseudos in the first offset
2155       addCFIPlaceholders(Offset, InsertBB);
2156     }
2157 
2158     const bool IsBlockEnd = MIB->isTerminator(Instr);
2159     IsLastInstrNop = MIB->isNoop(Instr);
2160     if (!IsLastInstrNop)
2161       LastInstrOffset = Offset;
2162     InsertBB->addInstruction(std::move(Instr));
2163 
2164     // Add associated CFI instrs. We always add the CFI instruction that is
2165     // located immediately after this instruction, since the next CFI
2166     // instruction reflects the change in state caused by this instruction.
2167     auto NextInstr = std::next(I);
2168     uint64_t CFIOffset;
2169     if (NextInstr != E)
2170       CFIOffset = NextInstr->first;
2171     else
2172       CFIOffset = getSize();
2173 
2174     // Note: this potentially invalidates instruction pointers/iterators.
2175     addCFIPlaceholders(CFIOffset, InsertBB);
2176 
2177     if (IsBlockEnd) {
2178       PrevBB = InsertBB;
2179       InsertBB = nullptr;
2180     }
2181   }
2182 
2183   if (BasicBlocks.empty()) {
2184     setSimple(false);
2185     return createNonFatalBOLTError("");
2186   }
2187 
2188   // Intermediate dump.
2189   LLVM_DEBUG(print(dbgs(), "after creating basic blocks"));
2190 
2191   // TODO: handle properly calls to no-return functions,
2192   // e.g. exit(3), etc. Otherwise we'll see a false fall-through
2193   // blocks.
2194 
2195   // Remove duplicates branches. We can get a bunch of them from jump tables.
2196   // Without doing jump table value profiling we don't have a use for extra
2197   // (duplicate) branches.
2198   llvm::sort(TakenBranches);
2199   auto NewEnd = std::unique(TakenBranches.begin(), TakenBranches.end());
2200   TakenBranches.erase(NewEnd, TakenBranches.end());
2201 
2202   for (std::pair<uint32_t, uint32_t> &Branch : TakenBranches) {
2203     LLVM_DEBUG(dbgs() << "registering branch [0x"
2204                       << Twine::utohexstr(Branch.first) << "] -> [0x"
2205                       << Twine::utohexstr(Branch.second) << "]\n");
2206     BinaryBasicBlock *FromBB = getBasicBlockContainingOffset(Branch.first);
2207     BinaryBasicBlock *ToBB = getBasicBlockAtOffset(Branch.second);
2208     if (!FromBB || !ToBB) {
2209       if (!FromBB)
2210         BC.errs() << "BOLT-ERROR: cannot find BB containing the branch.\n";
2211       if (!ToBB)
2212         BC.errs()
2213             << "BOLT-ERROR: cannot find BB containing branch destination.\n";
2214       return createFatalBOLTError(BC.generateBugReportMessage(
2215           "disassembly failed - inconsistent branch found.", *this));
2216     }
2217 
2218     FromBB->addSuccessor(ToBB);
2219   }
2220 
2221   // Add fall-through branches.
2222   PrevBB = nullptr;
2223   bool IsPrevFT = false; // Is previous block a fall-through.
2224   for (BinaryBasicBlock *BB : BasicBlocks) {
2225     if (IsPrevFT)
2226       PrevBB->addSuccessor(BB);
2227 
2228     if (BB->empty()) {
2229       IsPrevFT = true;
2230       PrevBB = BB;
2231       continue;
2232     }
2233 
2234     MCInst *LastInstr = BB->getLastNonPseudoInstr();
2235     assert(LastInstr &&
2236            "should have non-pseudo instruction in non-empty block");
2237 
2238     if (BB->succ_size() == 0) {
2239       // Since there's no existing successors, we know the last instruction is
2240       // not a conditional branch. Thus if it's a terminator, it shouldn't be a
2241       // fall-through.
2242       //
2243       // Conditional tail call is a special case since we don't add a taken
2244       // branch successor for it.
2245       IsPrevFT = !MIB->isTerminator(*LastInstr) ||
2246                  MIB->getConditionalTailCall(*LastInstr);
2247     } else if (BB->succ_size() == 1) {
2248       IsPrevFT = MIB->isConditionalBranch(*LastInstr);
2249     } else {
2250       IsPrevFT = false;
2251     }
2252 
2253     PrevBB = BB;
2254   }
2255 
2256   // Assign landing pads and throwers info.
2257   recomputeLandingPads();
2258 
2259   // Assign CFI information to each BB entry.
2260   annotateCFIState();
2261 
2262   // Annotate invoke instructions with GNU_args_size data.
2263   propagateGnuArgsSizeInfo(AllocatorId);
2264 
2265   // Set the basic block layout to the original order and set end offsets.
2266   PrevBB = nullptr;
2267   for (BinaryBasicBlock *BB : BasicBlocks) {
2268     Layout.addBasicBlock(BB);
2269     if (PrevBB)
2270       PrevBB->setEndOffset(BB->getOffset());
2271     PrevBB = BB;
2272   }
2273   PrevBB->setEndOffset(getSize());
2274 
2275   Layout.updateLayoutIndices();
2276 
2277   normalizeCFIState();
2278 
2279   // Clean-up memory taken by intermediate structures.
2280   //
2281   // NB: don't clear Labels list as we may need them if we mark the function
2282   //     as non-simple later in the process of discovering extra entry points.
2283   clearList(Instructions);
2284   clearList(OffsetToCFI);
2285   clearList(TakenBranches);
2286 
2287   // Update the state.
2288   CurrentState = State::CFG;
2289 
2290   // Make any necessary adjustments for indirect branches.
2291   if (!postProcessIndirectBranches(AllocatorId)) {
2292     if (opts::Verbosity) {
2293       BC.errs() << "BOLT-WARNING: failed to post-process indirect branches for "
2294                 << *this << '\n';
2295     }
2296     // In relocation mode we want to keep processing the function but avoid
2297     // optimizing it.
2298     setSimple(false);
2299   }
2300 
2301   clearList(ExternallyReferencedOffsets);
2302   clearList(UnknownIndirectBranchOffsets);
2303 
2304   return Error::success();
2305 }
2306 
2307 void BinaryFunction::postProcessCFG() {
2308   if (isSimple() && !BasicBlocks.empty()) {
2309     // Convert conditional tail call branches to conditional branches that jump
2310     // to a tail call.
2311     removeConditionalTailCalls();
2312 
2313     postProcessProfile();
2314 
2315     // Eliminate inconsistencies between branch instructions and CFG.
2316     postProcessBranches();
2317   }
2318 
2319   // The final cleanup of intermediate structures.
2320   clearList(IgnoredBranches);
2321 
2322   // Remove "Offset" annotations, unless we need an address-translation table
2323   // later. This has no cost, since annotations are allocated by a bumpptr
2324   // allocator and won't be released anyway until late in the pipeline.
2325   if (!requiresAddressTranslation() && !opts::Instrument) {
2326     for (BinaryBasicBlock &BB : blocks())
2327       for (MCInst &Inst : BB)
2328         BC.MIB->clearOffset(Inst);
2329   }
2330 
2331   assert((!isSimple() || validateCFG()) &&
2332          "invalid CFG detected after post-processing");
2333 }
2334 
2335 void BinaryFunction::removeTagsFromProfile() {
2336   for (BinaryBasicBlock *BB : BasicBlocks) {
2337     if (BB->ExecutionCount == BinaryBasicBlock::COUNT_NO_PROFILE)
2338       BB->ExecutionCount = 0;
2339     for (BinaryBasicBlock::BinaryBranchInfo &BI : BB->branch_info()) {
2340       if (BI.Count != BinaryBasicBlock::COUNT_NO_PROFILE &&
2341           BI.MispredictedCount != BinaryBasicBlock::COUNT_NO_PROFILE)
2342         continue;
2343       BI.Count = 0;
2344       BI.MispredictedCount = 0;
2345     }
2346   }
2347 }
2348 
2349 void BinaryFunction::removeConditionalTailCalls() {
2350   // Blocks to be appended at the end.
2351   std::vector<std::unique_ptr<BinaryBasicBlock>> NewBlocks;
2352 
2353   for (auto BBI = begin(); BBI != end(); ++BBI) {
2354     BinaryBasicBlock &BB = *BBI;
2355     MCInst *CTCInstr = BB.getLastNonPseudoInstr();
2356     if (!CTCInstr)
2357       continue;
2358 
2359     std::optional<uint64_t> TargetAddressOrNone =
2360         BC.MIB->getConditionalTailCall(*CTCInstr);
2361     if (!TargetAddressOrNone)
2362       continue;
2363 
2364     // Gather all necessary information about CTC instruction before
2365     // annotations are destroyed.
2366     const int32_t CFIStateBeforeCTC = BB.getCFIStateAtInstr(CTCInstr);
2367     uint64_t CTCTakenCount = BinaryBasicBlock::COUNT_NO_PROFILE;
2368     uint64_t CTCMispredCount = BinaryBasicBlock::COUNT_NO_PROFILE;
2369     if (hasValidProfile()) {
2370       CTCTakenCount = BC.MIB->getAnnotationWithDefault<uint64_t>(
2371           *CTCInstr, "CTCTakenCount");
2372       CTCMispredCount = BC.MIB->getAnnotationWithDefault<uint64_t>(
2373           *CTCInstr, "CTCMispredCount");
2374     }
2375 
2376     // Assert that the tail call does not throw.
2377     assert(!BC.MIB->getEHInfo(*CTCInstr) &&
2378            "found tail call with associated landing pad");
2379 
2380     // Create a basic block with an unconditional tail call instruction using
2381     // the same destination.
2382     const MCSymbol *CTCTargetLabel = BC.MIB->getTargetSymbol(*CTCInstr);
2383     assert(CTCTargetLabel && "symbol expected for conditional tail call");
2384     MCInst TailCallInstr;
2385     BC.MIB->createTailCall(TailCallInstr, CTCTargetLabel, BC.Ctx.get());
2386 
2387     // Move offset from CTCInstr to TailCallInstr.
2388     if (const std::optional<uint32_t> Offset = BC.MIB->getOffset(*CTCInstr)) {
2389       BC.MIB->setOffset(TailCallInstr, *Offset);
2390       BC.MIB->clearOffset(*CTCInstr);
2391     }
2392 
2393     // Link new BBs to the original input offset of the BB where the CTC
2394     // is, so we can map samples recorded in new BBs back to the original BB
2395     // seem in the input binary (if using BAT)
2396     std::unique_ptr<BinaryBasicBlock> TailCallBB =
2397         createBasicBlock(BC.Ctx->createNamedTempSymbol("TC"));
2398     TailCallBB->setOffset(BB.getInputOffset());
2399     TailCallBB->addInstruction(TailCallInstr);
2400     TailCallBB->setCFIState(CFIStateBeforeCTC);
2401 
2402     // Add CFG edge with profile info from BB to TailCallBB.
2403     BB.addSuccessor(TailCallBB.get(), CTCTakenCount, CTCMispredCount);
2404 
2405     // Add execution count for the block.
2406     TailCallBB->setExecutionCount(CTCTakenCount);
2407 
2408     BC.MIB->convertTailCallToJmp(*CTCInstr);
2409 
2410     BC.MIB->replaceBranchTarget(*CTCInstr, TailCallBB->getLabel(),
2411                                 BC.Ctx.get());
2412 
2413     // Add basic block to the list that will be added to the end.
2414     NewBlocks.emplace_back(std::move(TailCallBB));
2415 
2416     // Swap edges as the TailCallBB corresponds to the taken branch.
2417     BB.swapConditionalSuccessors();
2418 
2419     // This branch is no longer a conditional tail call.
2420     BC.MIB->unsetConditionalTailCall(*CTCInstr);
2421   }
2422 
2423   insertBasicBlocks(std::prev(end()), std::move(NewBlocks),
2424                     /* UpdateLayout */ true,
2425                     /* UpdateCFIState */ false);
2426 }
2427 
2428 uint64_t BinaryFunction::getFunctionScore() const {
2429   if (FunctionScore != -1)
2430     return FunctionScore;
2431 
2432   if (!isSimple() || !hasValidProfile()) {
2433     FunctionScore = 0;
2434     return FunctionScore;
2435   }
2436 
2437   uint64_t TotalScore = 0ULL;
2438   for (const BinaryBasicBlock &BB : blocks()) {
2439     uint64_t BBExecCount = BB.getExecutionCount();
2440     if (BBExecCount == BinaryBasicBlock::COUNT_NO_PROFILE)
2441       continue;
2442     TotalScore += BBExecCount * BB.getNumNonPseudos();
2443   }
2444   FunctionScore = TotalScore;
2445   return FunctionScore;
2446 }
2447 
2448 void BinaryFunction::annotateCFIState() {
2449   assert(CurrentState == State::Disassembled && "unexpected function state");
2450   assert(!BasicBlocks.empty() && "basic block list should not be empty");
2451 
2452   // This is an index of the last processed CFI in FDE CFI program.
2453   uint32_t State = 0;
2454 
2455   // This is an index of RememberState CFI reflecting effective state right
2456   // after execution of RestoreState CFI.
2457   //
2458   // It differs from State iff the CFI at (State-1)
2459   // was RestoreState (modulo GNU_args_size CFIs, which are ignored).
2460   //
2461   // This allows us to generate shorter replay sequences when producing new
2462   // CFI programs.
2463   uint32_t EffectiveState = 0;
2464 
2465   // For tracking RememberState/RestoreState sequences.
2466   std::stack<uint32_t> StateStack;
2467 
2468   for (BinaryBasicBlock *BB : BasicBlocks) {
2469     BB->setCFIState(EffectiveState);
2470 
2471     for (const MCInst &Instr : *BB) {
2472       const MCCFIInstruction *CFI = getCFIFor(Instr);
2473       if (!CFI)
2474         continue;
2475 
2476       ++State;
2477 
2478       switch (CFI->getOperation()) {
2479       case MCCFIInstruction::OpRememberState:
2480         StateStack.push(EffectiveState);
2481         EffectiveState = State;
2482         break;
2483       case MCCFIInstruction::OpRestoreState:
2484         assert(!StateStack.empty() && "corrupt CFI stack");
2485         EffectiveState = StateStack.top();
2486         StateStack.pop();
2487         break;
2488       case MCCFIInstruction::OpGnuArgsSize:
2489         // OpGnuArgsSize CFIs do not affect the CFI state.
2490         break;
2491       default:
2492         // Any other CFI updates the state.
2493         EffectiveState = State;
2494         break;
2495       }
2496     }
2497   }
2498 
2499   if (opts::Verbosity >= 1 && !StateStack.empty()) {
2500     BC.errs() << "BOLT-WARNING: non-empty CFI stack at the end of " << *this
2501               << '\n';
2502   }
2503 }
2504 
2505 namespace {
2506 
2507 /// Our full interpretation of a DWARF CFI machine state at a given point
2508 struct CFISnapshot {
2509   /// CFA register number and offset defining the canonical frame at this
2510   /// point, or the number of a rule (CFI state) that computes it with a
2511   /// DWARF expression. This number will be negative if it refers to a CFI
2512   /// located in the CIE instead of the FDE.
2513   uint32_t CFAReg;
2514   int32_t CFAOffset;
2515   int32_t CFARule;
2516   /// Mapping of rules (CFI states) that define the location of each
2517   /// register. If absent, no rule defining the location of such register
2518   /// was ever read. This number will be negative if it refers to a CFI
2519   /// located in the CIE instead of the FDE.
2520   DenseMap<int32_t, int32_t> RegRule;
2521 
2522   /// References to CIE, FDE and expanded instructions after a restore state
2523   const BinaryFunction::CFIInstrMapType &CIE;
2524   const BinaryFunction::CFIInstrMapType &FDE;
2525   const DenseMap<int32_t, SmallVector<int32_t, 4>> &FrameRestoreEquivalents;
2526 
2527   /// Current FDE CFI number representing the state where the snapshot is at
2528   int32_t CurState;
2529 
2530   /// Used when we don't have information about which state/rule to apply
2531   /// to recover the location of either the CFA or a specific register
2532   constexpr static int32_t UNKNOWN = std::numeric_limits<int32_t>::min();
2533 
2534 private:
2535   /// Update our snapshot by executing a single CFI
2536   void update(const MCCFIInstruction &Instr, int32_t RuleNumber) {
2537     switch (Instr.getOperation()) {
2538     case MCCFIInstruction::OpSameValue:
2539     case MCCFIInstruction::OpRelOffset:
2540     case MCCFIInstruction::OpOffset:
2541     case MCCFIInstruction::OpRestore:
2542     case MCCFIInstruction::OpUndefined:
2543     case MCCFIInstruction::OpRegister:
2544       RegRule[Instr.getRegister()] = RuleNumber;
2545       break;
2546     case MCCFIInstruction::OpDefCfaRegister:
2547       CFAReg = Instr.getRegister();
2548       CFARule = UNKNOWN;
2549 
2550       // This shouldn't happen according to the spec but GNU binutils on RISC-V
2551       // emits a DW_CFA_def_cfa_register in CIE's which leaves the offset
2552       // unspecified. Both readelf and llvm-dwarfdump interpret the offset as 0
2553       // in this case so let's do the same.
2554       if (CFAOffset == UNKNOWN)
2555         CFAOffset = 0;
2556       break;
2557     case MCCFIInstruction::OpDefCfaOffset:
2558       CFAOffset = Instr.getOffset();
2559       CFARule = UNKNOWN;
2560       break;
2561     case MCCFIInstruction::OpDefCfa:
2562       CFAReg = Instr.getRegister();
2563       CFAOffset = Instr.getOffset();
2564       CFARule = UNKNOWN;
2565       break;
2566     case MCCFIInstruction::OpEscape: {
2567       std::optional<uint8_t> Reg =
2568           readDWARFExpressionTargetReg(Instr.getValues());
2569       // Handle DW_CFA_def_cfa_expression
2570       if (!Reg) {
2571         CFARule = RuleNumber;
2572         break;
2573       }
2574       RegRule[*Reg] = RuleNumber;
2575       break;
2576     }
2577     case MCCFIInstruction::OpAdjustCfaOffset:
2578     case MCCFIInstruction::OpWindowSave:
2579     case MCCFIInstruction::OpNegateRAState:
2580     case MCCFIInstruction::OpNegateRAStateWithPC:
2581     case MCCFIInstruction::OpLLVMDefAspaceCfa:
2582     case MCCFIInstruction::OpLabel:
2583     case MCCFIInstruction::OpValOffset:
2584       llvm_unreachable("unsupported CFI opcode");
2585       break;
2586     case MCCFIInstruction::OpRememberState:
2587     case MCCFIInstruction::OpRestoreState:
2588     case MCCFIInstruction::OpGnuArgsSize:
2589       // do not affect CFI state
2590       break;
2591     }
2592   }
2593 
2594 public:
2595   /// Advance state reading FDE CFI instructions up to State number
2596   void advanceTo(int32_t State) {
2597     for (int32_t I = CurState, E = State; I != E; ++I) {
2598       const MCCFIInstruction &Instr = FDE[I];
2599       if (Instr.getOperation() != MCCFIInstruction::OpRestoreState) {
2600         update(Instr, I);
2601         continue;
2602       }
2603       // If restore state instruction, fetch the equivalent CFIs that have
2604       // the same effect of this restore. This is used to ensure remember-
2605       // restore pairs are completely removed.
2606       auto Iter = FrameRestoreEquivalents.find(I);
2607       if (Iter == FrameRestoreEquivalents.end())
2608         continue;
2609       for (int32_t RuleNumber : Iter->second)
2610         update(FDE[RuleNumber], RuleNumber);
2611     }
2612 
2613     assert(((CFAReg != (uint32_t)UNKNOWN && CFAOffset != UNKNOWN) ||
2614             CFARule != UNKNOWN) &&
2615            "CIE did not define default CFA?");
2616 
2617     CurState = State;
2618   }
2619 
2620   /// Interpret all CIE and FDE instructions up until CFI State number and
2621   /// populate this snapshot
2622   CFISnapshot(
2623       const BinaryFunction::CFIInstrMapType &CIE,
2624       const BinaryFunction::CFIInstrMapType &FDE,
2625       const DenseMap<int32_t, SmallVector<int32_t, 4>> &FrameRestoreEquivalents,
2626       int32_t State)
2627       : CIE(CIE), FDE(FDE), FrameRestoreEquivalents(FrameRestoreEquivalents) {
2628     CFAReg = UNKNOWN;
2629     CFAOffset = UNKNOWN;
2630     CFARule = UNKNOWN;
2631     CurState = 0;
2632 
2633     for (int32_t I = 0, E = CIE.size(); I != E; ++I) {
2634       const MCCFIInstruction &Instr = CIE[I];
2635       update(Instr, -I);
2636     }
2637 
2638     advanceTo(State);
2639   }
2640 };
2641 
2642 /// A CFI snapshot with the capability of checking if incremental additions to
2643 /// it are redundant. This is used to ensure we do not emit two CFI instructions
2644 /// back-to-back that are doing the same state change, or to avoid emitting a
2645 /// CFI at all when the state at that point would not be modified after that CFI
2646 struct CFISnapshotDiff : public CFISnapshot {
2647   bool RestoredCFAReg{false};
2648   bool RestoredCFAOffset{false};
2649   DenseMap<int32_t, bool> RestoredRegs;
2650 
2651   CFISnapshotDiff(const CFISnapshot &S) : CFISnapshot(S) {}
2652 
2653   CFISnapshotDiff(
2654       const BinaryFunction::CFIInstrMapType &CIE,
2655       const BinaryFunction::CFIInstrMapType &FDE,
2656       const DenseMap<int32_t, SmallVector<int32_t, 4>> &FrameRestoreEquivalents,
2657       int32_t State)
2658       : CFISnapshot(CIE, FDE, FrameRestoreEquivalents, State) {}
2659 
2660   /// Return true if applying Instr to this state is redundant and can be
2661   /// dismissed.
2662   bool isRedundant(const MCCFIInstruction &Instr) {
2663     switch (Instr.getOperation()) {
2664     case MCCFIInstruction::OpSameValue:
2665     case MCCFIInstruction::OpRelOffset:
2666     case MCCFIInstruction::OpOffset:
2667     case MCCFIInstruction::OpRestore:
2668     case MCCFIInstruction::OpUndefined:
2669     case MCCFIInstruction::OpRegister:
2670     case MCCFIInstruction::OpEscape: {
2671       uint32_t Reg;
2672       if (Instr.getOperation() != MCCFIInstruction::OpEscape) {
2673         Reg = Instr.getRegister();
2674       } else {
2675         std::optional<uint8_t> R =
2676             readDWARFExpressionTargetReg(Instr.getValues());
2677         // Handle DW_CFA_def_cfa_expression
2678         if (!R) {
2679           if (RestoredCFAReg && RestoredCFAOffset)
2680             return true;
2681           RestoredCFAReg = true;
2682           RestoredCFAOffset = true;
2683           return false;
2684         }
2685         Reg = *R;
2686       }
2687       if (RestoredRegs[Reg])
2688         return true;
2689       RestoredRegs[Reg] = true;
2690       const int32_t CurRegRule = RegRule.contains(Reg) ? RegRule[Reg] : UNKNOWN;
2691       if (CurRegRule == UNKNOWN) {
2692         if (Instr.getOperation() == MCCFIInstruction::OpRestore ||
2693             Instr.getOperation() == MCCFIInstruction::OpSameValue)
2694           return true;
2695         return false;
2696       }
2697       const MCCFIInstruction &LastDef =
2698           CurRegRule < 0 ? CIE[-CurRegRule] : FDE[CurRegRule];
2699       return LastDef == Instr;
2700     }
2701     case MCCFIInstruction::OpDefCfaRegister:
2702       if (RestoredCFAReg)
2703         return true;
2704       RestoredCFAReg = true;
2705       return CFAReg == Instr.getRegister();
2706     case MCCFIInstruction::OpDefCfaOffset:
2707       if (RestoredCFAOffset)
2708         return true;
2709       RestoredCFAOffset = true;
2710       return CFAOffset == Instr.getOffset();
2711     case MCCFIInstruction::OpDefCfa:
2712       if (RestoredCFAReg && RestoredCFAOffset)
2713         return true;
2714       RestoredCFAReg = true;
2715       RestoredCFAOffset = true;
2716       return CFAReg == Instr.getRegister() && CFAOffset == Instr.getOffset();
2717     case MCCFIInstruction::OpAdjustCfaOffset:
2718     case MCCFIInstruction::OpWindowSave:
2719     case MCCFIInstruction::OpNegateRAState:
2720     case MCCFIInstruction::OpNegateRAStateWithPC:
2721     case MCCFIInstruction::OpLLVMDefAspaceCfa:
2722     case MCCFIInstruction::OpLabel:
2723     case MCCFIInstruction::OpValOffset:
2724       llvm_unreachable("unsupported CFI opcode");
2725       return false;
2726     case MCCFIInstruction::OpRememberState:
2727     case MCCFIInstruction::OpRestoreState:
2728     case MCCFIInstruction::OpGnuArgsSize:
2729       // do not affect CFI state
2730       return true;
2731     }
2732     return false;
2733   }
2734 };
2735 
2736 } // end anonymous namespace
2737 
2738 bool BinaryFunction::replayCFIInstrs(int32_t FromState, int32_t ToState,
2739                                      BinaryBasicBlock *InBB,
2740                                      BinaryBasicBlock::iterator InsertIt) {
2741   if (FromState == ToState)
2742     return true;
2743   assert(FromState < ToState && "can only replay CFIs forward");
2744 
2745   CFISnapshotDiff CFIDiff(CIEFrameInstructions, FrameInstructions,
2746                           FrameRestoreEquivalents, FromState);
2747 
2748   std::vector<uint32_t> NewCFIs;
2749   for (int32_t CurState = FromState; CurState < ToState; ++CurState) {
2750     MCCFIInstruction *Instr = &FrameInstructions[CurState];
2751     if (Instr->getOperation() == MCCFIInstruction::OpRestoreState) {
2752       auto Iter = FrameRestoreEquivalents.find(CurState);
2753       assert(Iter != FrameRestoreEquivalents.end());
2754       NewCFIs.insert(NewCFIs.end(), Iter->second.begin(), Iter->second.end());
2755       // RestoreState / Remember will be filtered out later by CFISnapshotDiff,
2756       // so we might as well fall-through here.
2757     }
2758     NewCFIs.push_back(CurState);
2759   }
2760 
2761   // Replay instructions while avoiding duplicates
2762   for (int32_t State : llvm::reverse(NewCFIs)) {
2763     if (CFIDiff.isRedundant(FrameInstructions[State]))
2764       continue;
2765     InsertIt = addCFIPseudo(InBB, InsertIt, State);
2766   }
2767 
2768   return true;
2769 }
2770 
2771 SmallVector<int32_t, 4>
2772 BinaryFunction::unwindCFIState(int32_t FromState, int32_t ToState,
2773                                BinaryBasicBlock *InBB,
2774                                BinaryBasicBlock::iterator &InsertIt) {
2775   SmallVector<int32_t, 4> NewStates;
2776 
2777   CFISnapshot ToCFITable(CIEFrameInstructions, FrameInstructions,
2778                          FrameRestoreEquivalents, ToState);
2779   CFISnapshotDiff FromCFITable(ToCFITable);
2780   FromCFITable.advanceTo(FromState);
2781 
2782   auto undoStateDefCfa = [&]() {
2783     if (ToCFITable.CFARule == CFISnapshot::UNKNOWN) {
2784       FrameInstructions.emplace_back(MCCFIInstruction::cfiDefCfa(
2785           nullptr, ToCFITable.CFAReg, ToCFITable.CFAOffset));
2786       if (FromCFITable.isRedundant(FrameInstructions.back())) {
2787         FrameInstructions.pop_back();
2788         return;
2789       }
2790       NewStates.push_back(FrameInstructions.size() - 1);
2791       InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size() - 1);
2792       ++InsertIt;
2793     } else if (ToCFITable.CFARule < 0) {
2794       if (FromCFITable.isRedundant(CIEFrameInstructions[-ToCFITable.CFARule]))
2795         return;
2796       NewStates.push_back(FrameInstructions.size());
2797       InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size());
2798       ++InsertIt;
2799       FrameInstructions.emplace_back(CIEFrameInstructions[-ToCFITable.CFARule]);
2800     } else if (!FromCFITable.isRedundant(
2801                    FrameInstructions[ToCFITable.CFARule])) {
2802       NewStates.push_back(ToCFITable.CFARule);
2803       InsertIt = addCFIPseudo(InBB, InsertIt, ToCFITable.CFARule);
2804       ++InsertIt;
2805     }
2806   };
2807 
2808   auto undoState = [&](const MCCFIInstruction &Instr) {
2809     switch (Instr.getOperation()) {
2810     case MCCFIInstruction::OpRememberState:
2811     case MCCFIInstruction::OpRestoreState:
2812       break;
2813     case MCCFIInstruction::OpSameValue:
2814     case MCCFIInstruction::OpRelOffset:
2815     case MCCFIInstruction::OpOffset:
2816     case MCCFIInstruction::OpRestore:
2817     case MCCFIInstruction::OpUndefined:
2818     case MCCFIInstruction::OpEscape:
2819     case MCCFIInstruction::OpRegister: {
2820       uint32_t Reg;
2821       if (Instr.getOperation() != MCCFIInstruction::OpEscape) {
2822         Reg = Instr.getRegister();
2823       } else {
2824         std::optional<uint8_t> R =
2825             readDWARFExpressionTargetReg(Instr.getValues());
2826         // Handle DW_CFA_def_cfa_expression
2827         if (!R) {
2828           undoStateDefCfa();
2829           return;
2830         }
2831         Reg = *R;
2832       }
2833 
2834       if (!ToCFITable.RegRule.contains(Reg)) {
2835         FrameInstructions.emplace_back(
2836             MCCFIInstruction::createRestore(nullptr, Reg));
2837         if (FromCFITable.isRedundant(FrameInstructions.back())) {
2838           FrameInstructions.pop_back();
2839           break;
2840         }
2841         NewStates.push_back(FrameInstructions.size() - 1);
2842         InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size() - 1);
2843         ++InsertIt;
2844         break;
2845       }
2846       const int32_t Rule = ToCFITable.RegRule[Reg];
2847       if (Rule < 0) {
2848         if (FromCFITable.isRedundant(CIEFrameInstructions[-Rule]))
2849           break;
2850         NewStates.push_back(FrameInstructions.size());
2851         InsertIt = addCFIPseudo(InBB, InsertIt, FrameInstructions.size());
2852         ++InsertIt;
2853         FrameInstructions.emplace_back(CIEFrameInstructions[-Rule]);
2854         break;
2855       }
2856       if (FromCFITable.isRedundant(FrameInstructions[Rule]))
2857         break;
2858       NewStates.push_back(Rule);
2859       InsertIt = addCFIPseudo(InBB, InsertIt, Rule);
2860       ++InsertIt;
2861       break;
2862     }
2863     case MCCFIInstruction::OpDefCfaRegister:
2864     case MCCFIInstruction::OpDefCfaOffset:
2865     case MCCFIInstruction::OpDefCfa:
2866       undoStateDefCfa();
2867       break;
2868     case MCCFIInstruction::OpAdjustCfaOffset:
2869     case MCCFIInstruction::OpWindowSave:
2870     case MCCFIInstruction::OpNegateRAState:
2871     case MCCFIInstruction::OpNegateRAStateWithPC:
2872     case MCCFIInstruction::OpLLVMDefAspaceCfa:
2873     case MCCFIInstruction::OpLabel:
2874     case MCCFIInstruction::OpValOffset:
2875       llvm_unreachable("unsupported CFI opcode");
2876       break;
2877     case MCCFIInstruction::OpGnuArgsSize:
2878       // do not affect CFI state
2879       break;
2880     }
2881   };
2882 
2883   // Undo all modifications from ToState to FromState
2884   for (int32_t I = ToState, E = FromState; I != E; ++I) {
2885     const MCCFIInstruction &Instr = FrameInstructions[I];
2886     if (Instr.getOperation() != MCCFIInstruction::OpRestoreState) {
2887       undoState(Instr);
2888       continue;
2889     }
2890     auto Iter = FrameRestoreEquivalents.find(I);
2891     if (Iter == FrameRestoreEquivalents.end())
2892       continue;
2893     for (int32_t State : Iter->second)
2894       undoState(FrameInstructions[State]);
2895   }
2896 
2897   return NewStates;
2898 }
2899 
2900 void BinaryFunction::normalizeCFIState() {
2901   // Reordering blocks with remember-restore state instructions can be specially
2902   // tricky. When rewriting the CFI, we omit remember-restore state instructions
2903   // entirely. For restore state, we build a map expanding each restore to the
2904   // equivalent unwindCFIState sequence required at that point to achieve the
2905   // same effect of the restore. All remember state are then just ignored.
2906   std::stack<int32_t> Stack;
2907   for (BinaryBasicBlock *CurBB : Layout.blocks()) {
2908     for (auto II = CurBB->begin(); II != CurBB->end(); ++II) {
2909       if (const MCCFIInstruction *CFI = getCFIFor(*II)) {
2910         if (CFI->getOperation() == MCCFIInstruction::OpRememberState) {
2911           Stack.push(II->getOperand(0).getImm());
2912           continue;
2913         }
2914         if (CFI->getOperation() == MCCFIInstruction::OpRestoreState) {
2915           const int32_t RememberState = Stack.top();
2916           const int32_t CurState = II->getOperand(0).getImm();
2917           FrameRestoreEquivalents[CurState] =
2918               unwindCFIState(CurState, RememberState, CurBB, II);
2919           Stack.pop();
2920         }
2921       }
2922     }
2923   }
2924 }
2925 
2926 bool BinaryFunction::finalizeCFIState() {
2927   LLVM_DEBUG(
2928       dbgs() << "Trying to fix CFI states for each BB after reordering.\n");
2929   LLVM_DEBUG(dbgs() << "This is the list of CFI states for each BB of " << *this
2930                     << ": ");
2931 
2932   const char *Sep = "";
2933   (void)Sep;
2934   for (FunctionFragment &FF : Layout.fragments()) {
2935     // Hot-cold border: at start of each region (with a different FDE) we need
2936     // to reset the CFI state.
2937     int32_t State = 0;
2938 
2939     for (BinaryBasicBlock *BB : FF) {
2940       const int32_t CFIStateAtExit = BB->getCFIStateAtExit();
2941 
2942       // We need to recover the correct state if it doesn't match expected
2943       // state at BB entry point.
2944       if (BB->getCFIState() < State) {
2945         // In this case, State is currently higher than what this BB expect it
2946         // to be. To solve this, we need to insert CFI instructions to undo
2947         // the effect of all CFI from BB's state to current State.
2948         auto InsertIt = BB->begin();
2949         unwindCFIState(State, BB->getCFIState(), BB, InsertIt);
2950       } else if (BB->getCFIState() > State) {
2951         // If BB's CFI state is greater than State, it means we are behind in
2952         // the state. Just emit all instructions to reach this state at the
2953         // beginning of this BB. If this sequence of instructions involve
2954         // remember state or restore state, bail out.
2955         if (!replayCFIInstrs(State, BB->getCFIState(), BB, BB->begin()))
2956           return false;
2957       }
2958 
2959       State = CFIStateAtExit;
2960       LLVM_DEBUG(dbgs() << Sep << State; Sep = ", ");
2961     }
2962   }
2963   LLVM_DEBUG(dbgs() << "\n");
2964 
2965   for (BinaryBasicBlock &BB : blocks()) {
2966     for (auto II = BB.begin(); II != BB.end();) {
2967       const MCCFIInstruction *CFI = getCFIFor(*II);
2968       if (CFI && (CFI->getOperation() == MCCFIInstruction::OpRememberState ||
2969                   CFI->getOperation() == MCCFIInstruction::OpRestoreState)) {
2970         II = BB.eraseInstruction(II);
2971       } else {
2972         ++II;
2973       }
2974     }
2975   }
2976 
2977   return true;
2978 }
2979 
2980 bool BinaryFunction::requiresAddressTranslation() const {
2981   return opts::EnableBAT || hasSDTMarker() || hasPseudoProbe();
2982 }
2983 
2984 bool BinaryFunction::requiresAddressMap() const {
2985   if (isInjected())
2986     return false;
2987 
2988   return opts::UpdateDebugSections || isMultiEntry() ||
2989          requiresAddressTranslation();
2990 }
2991 
2992 uint64_t BinaryFunction::getInstructionCount() const {
2993   uint64_t Count = 0;
2994   for (const BinaryBasicBlock &BB : blocks())
2995     Count += BB.getNumNonPseudos();
2996   return Count;
2997 }
2998 
2999 void BinaryFunction::clearDisasmState() {
3000   clearList(Instructions);
3001   clearList(IgnoredBranches);
3002   clearList(TakenBranches);
3003 
3004   if (BC.HasRelocations) {
3005     for (std::pair<const uint32_t, MCSymbol *> &LI : Labels)
3006       BC.UndefinedSymbols.insert(LI.second);
3007     for (MCSymbol *const EndLabel : FunctionEndLabels)
3008       if (EndLabel)
3009         BC.UndefinedSymbols.insert(EndLabel);
3010   }
3011 }
3012 
3013 void BinaryFunction::setTrapOnEntry() {
3014   clearDisasmState();
3015 
3016   forEachEntryPoint([&](uint64_t Offset, const MCSymbol *Label) -> bool {
3017     MCInst TrapInstr;
3018     BC.MIB->createTrap(TrapInstr);
3019     addInstruction(Offset, std::move(TrapInstr));
3020     return true;
3021   });
3022 
3023   TrapsOnEntry = true;
3024 }
3025 
3026 void BinaryFunction::setIgnored() {
3027   if (opts::processAllFunctions()) {
3028     // We can accept ignored functions before they've been disassembled.
3029     // In that case, they would still get disassembled and emited, but not
3030     // optimized.
3031     assert(CurrentState == State::Empty &&
3032            "cannot ignore non-empty functions in current mode");
3033     IsIgnored = true;
3034     return;
3035   }
3036 
3037   clearDisasmState();
3038 
3039   // Clear CFG state too.
3040   if (hasCFG()) {
3041     releaseCFG();
3042 
3043     for (BinaryBasicBlock *BB : BasicBlocks)
3044       delete BB;
3045     clearList(BasicBlocks);
3046 
3047     for (BinaryBasicBlock *BB : DeletedBasicBlocks)
3048       delete BB;
3049     clearList(DeletedBasicBlocks);
3050 
3051     Layout.clear();
3052   }
3053 
3054   CurrentState = State::Empty;
3055 
3056   IsIgnored = true;
3057   IsSimple = false;
3058   LLVM_DEBUG(dbgs() << "Ignoring " << getPrintName() << '\n');
3059 }
3060 
3061 void BinaryFunction::duplicateConstantIslands() {
3062   assert(Islands && "function expected to have constant islands");
3063 
3064   for (BinaryBasicBlock *BB : getLayout().blocks()) {
3065     if (!BB->isCold())
3066       continue;
3067 
3068     for (MCInst &Inst : *BB) {
3069       int OpNum = 0;
3070       for (MCOperand &Operand : Inst) {
3071         if (!Operand.isExpr()) {
3072           ++OpNum;
3073           continue;
3074         }
3075         const MCSymbol *Symbol = BC.MIB->getTargetSymbol(Inst, OpNum);
3076         // Check if this is an island symbol
3077         if (!Islands->Symbols.count(Symbol) &&
3078             !Islands->ProxySymbols.count(Symbol))
3079           continue;
3080 
3081         // Create cold symbol, if missing
3082         auto ISym = Islands->ColdSymbols.find(Symbol);
3083         MCSymbol *ColdSymbol;
3084         if (ISym != Islands->ColdSymbols.end()) {
3085           ColdSymbol = ISym->second;
3086         } else {
3087           ColdSymbol = BC.Ctx->getOrCreateSymbol(Symbol->getName() + ".cold");
3088           Islands->ColdSymbols[Symbol] = ColdSymbol;
3089           // Check if this is a proxy island symbol and update owner proxy map
3090           if (Islands->ProxySymbols.count(Symbol)) {
3091             BinaryFunction *Owner = Islands->ProxySymbols[Symbol];
3092             auto IProxiedSym = Owner->Islands->Proxies[this].find(Symbol);
3093             Owner->Islands->ColdProxies[this][IProxiedSym->second] = ColdSymbol;
3094           }
3095         }
3096 
3097         // Update instruction reference
3098         Operand = MCOperand::createExpr(BC.MIB->getTargetExprFor(
3099             Inst,
3100             MCSymbolRefExpr::create(ColdSymbol, MCSymbolRefExpr::VK_None,
3101                                     *BC.Ctx),
3102             *BC.Ctx, 0));
3103         ++OpNum;
3104       }
3105     }
3106   }
3107 }
3108 
3109 #ifndef MAX_PATH
3110 #define MAX_PATH 255
3111 #endif
3112 
3113 static std::string constructFilename(std::string Filename,
3114                                      std::string Annotation,
3115                                      std::string Suffix) {
3116   std::replace(Filename.begin(), Filename.end(), '/', '-');
3117   if (!Annotation.empty())
3118     Annotation.insert(0, "-");
3119   if (Filename.size() + Annotation.size() + Suffix.size() > MAX_PATH) {
3120     assert(Suffix.size() + Annotation.size() <= MAX_PATH);
3121     Filename.resize(MAX_PATH - (Suffix.size() + Annotation.size()));
3122   }
3123   Filename += Annotation;
3124   Filename += Suffix;
3125   return Filename;
3126 }
3127 
3128 static std::string formatEscapes(const std::string &Str) {
3129   std::string Result;
3130   for (unsigned I = 0; I < Str.size(); ++I) {
3131     char C = Str[I];
3132     switch (C) {
3133     case '\n':
3134       Result += "&#13;";
3135       break;
3136     case '"':
3137       break;
3138     default:
3139       Result += C;
3140       break;
3141     }
3142   }
3143   return Result;
3144 }
3145 
3146 void BinaryFunction::dumpGraph(raw_ostream &OS) const {
3147   OS << "digraph \"" << getPrintName() << "\" {\n"
3148      << "node [fontname=courier, shape=box, style=filled, colorscheme=brbg9]\n";
3149   uint64_t Offset = Address;
3150   for (BinaryBasicBlock *BB : BasicBlocks) {
3151     auto LayoutPos = find(Layout.blocks(), BB);
3152     unsigned LayoutIndex = LayoutPos - Layout.block_begin();
3153     const char *ColdStr = BB->isCold() ? " (cold)" : "";
3154     std::vector<std::string> Attrs;
3155     // Bold box for entry points
3156     if (isEntryPoint(*BB))
3157       Attrs.push_back("penwidth=2");
3158     if (BLI && BLI->getLoopFor(BB)) {
3159       // Distinguish innermost loops
3160       const BinaryLoop *Loop = BLI->getLoopFor(BB);
3161       if (Loop->isInnermost())
3162         Attrs.push_back("fillcolor=6");
3163       else // some outer loop
3164         Attrs.push_back("fillcolor=4");
3165     } else { // non-loopy code
3166       Attrs.push_back("fillcolor=5");
3167     }
3168     ListSeparator LS;
3169     OS << "\"" << BB->getName() << "\" [";
3170     for (StringRef Attr : Attrs)
3171       OS << LS << Attr;
3172     OS << "]\n";
3173     OS << format("\"%s\" [label=\"%s%s\\n(C:%lu,O:%lu,I:%u,L:%u,CFI:%u)\\n",
3174                  BB->getName().data(), BB->getName().data(), ColdStr,
3175                  BB->getKnownExecutionCount(), BB->getOffset(), getIndex(BB),
3176                  LayoutIndex, BB->getCFIState());
3177 
3178     if (opts::DotToolTipCode) {
3179       std::string Str;
3180       raw_string_ostream CS(Str);
3181       Offset = BC.printInstructions(CS, BB->begin(), BB->end(), Offset, this,
3182                                     /* PrintMCInst = */ false,
3183                                     /* PrintMemData = */ false,
3184                                     /* PrintRelocations = */ false,
3185                                     /* Endl = */ R"(\\l)");
3186       OS << formatEscapes(CS.str()) << '\n';
3187     }
3188     OS << "\"]\n";
3189 
3190     // analyzeBranch is just used to get the names of the branch
3191     // opcodes.
3192     const MCSymbol *TBB = nullptr;
3193     const MCSymbol *FBB = nullptr;
3194     MCInst *CondBranch = nullptr;
3195     MCInst *UncondBranch = nullptr;
3196     const bool Success = BB->analyzeBranch(TBB, FBB, CondBranch, UncondBranch);
3197 
3198     const MCInst *LastInstr = BB->getLastNonPseudoInstr();
3199     const bool IsJumpTable = LastInstr && BC.MIB->getJumpTable(*LastInstr);
3200 
3201     auto BI = BB->branch_info_begin();
3202     for (BinaryBasicBlock *Succ : BB->successors()) {
3203       std::string Branch;
3204       if (Success) {
3205         if (Succ == BB->getConditionalSuccessor(true)) {
3206           Branch = CondBranch ? std::string(BC.InstPrinter->getOpcodeName(
3207                                     CondBranch->getOpcode()))
3208                               : "TB";
3209         } else if (Succ == BB->getConditionalSuccessor(false)) {
3210           Branch = UncondBranch ? std::string(BC.InstPrinter->getOpcodeName(
3211                                       UncondBranch->getOpcode()))
3212                                 : "FB";
3213         } else {
3214           Branch = "FT";
3215         }
3216       }
3217       if (IsJumpTable)
3218         Branch = "JT";
3219       OS << format("\"%s\" -> \"%s\" [label=\"%s", BB->getName().data(),
3220                    Succ->getName().data(), Branch.c_str());
3221 
3222       if (BB->getExecutionCount() != COUNT_NO_PROFILE &&
3223           BI->MispredictedCount != BinaryBasicBlock::COUNT_INFERRED) {
3224         OS << "\\n(C:" << BI->Count << ",M:" << BI->MispredictedCount << ")";
3225       } else if (ExecutionCount != COUNT_NO_PROFILE &&
3226                  BI->Count != BinaryBasicBlock::COUNT_NO_PROFILE) {
3227         OS << "\\n(IC:" << BI->Count << ")";
3228       }
3229       OS << "\"]\n";
3230 
3231       ++BI;
3232     }
3233     for (BinaryBasicBlock *LP : BB->landing_pads()) {
3234       OS << format("\"%s\" -> \"%s\" [constraint=false style=dashed]\n",
3235                    BB->getName().data(), LP->getName().data());
3236     }
3237   }
3238   OS << "}\n";
3239 }
3240 
3241 void BinaryFunction::viewGraph() const {
3242   SmallString<MAX_PATH> Filename;
3243   if (std::error_code EC =
3244           sys::fs::createTemporaryFile("bolt-cfg", "dot", Filename)) {
3245     BC.errs() << "BOLT-ERROR: " << EC.message() << ", unable to create "
3246               << " bolt-cfg-XXXXX.dot temporary file.\n";
3247     return;
3248   }
3249   dumpGraphToFile(std::string(Filename));
3250   if (DisplayGraph(Filename))
3251     BC.errs() << "BOLT-ERROR: Can't display " << Filename
3252               << " with graphviz.\n";
3253   if (std::error_code EC = sys::fs::remove(Filename)) {
3254     BC.errs() << "BOLT-WARNING: " << EC.message() << ", failed to remove "
3255               << Filename << "\n";
3256   }
3257 }
3258 
3259 void BinaryFunction::dumpGraphForPass(std::string Annotation) const {
3260   if (!opts::shouldPrint(*this))
3261     return;
3262 
3263   std::string Filename = constructFilename(getPrintName(), Annotation, ".dot");
3264   if (opts::Verbosity >= 1)
3265     BC.outs() << "BOLT-INFO: dumping CFG to " << Filename << "\n";
3266   dumpGraphToFile(Filename);
3267 }
3268 
3269 void BinaryFunction::dumpGraphToFile(std::string Filename) const {
3270   std::error_code EC;
3271   raw_fd_ostream of(Filename, EC, sys::fs::OF_None);
3272   if (EC) {
3273     if (opts::Verbosity >= 1) {
3274       BC.errs() << "BOLT-WARNING: " << EC.message() << ", unable to open "
3275                 << Filename << " for output.\n";
3276     }
3277     return;
3278   }
3279   dumpGraph(of);
3280 }
3281 
3282 bool BinaryFunction::validateCFG() const {
3283   // Skip the validation of CFG after it is finalized
3284   if (CurrentState == State::CFG_Finalized)
3285     return true;
3286 
3287   for (BinaryBasicBlock *BB : BasicBlocks)
3288     if (!BB->validateSuccessorInvariants())
3289       return false;
3290 
3291   // Make sure all blocks in CFG are valid.
3292   auto validateBlock = [this](const BinaryBasicBlock *BB, StringRef Desc) {
3293     if (!BB->isValid()) {
3294       BC.errs() << "BOLT-ERROR: deleted " << Desc << " " << BB->getName()
3295                 << " detected in:\n";
3296       this->dump();
3297       return false;
3298     }
3299     return true;
3300   };
3301   for (const BinaryBasicBlock *BB : BasicBlocks) {
3302     if (!validateBlock(BB, "block"))
3303       return false;
3304     for (const BinaryBasicBlock *PredBB : BB->predecessors())
3305       if (!validateBlock(PredBB, "predecessor"))
3306         return false;
3307     for (const BinaryBasicBlock *SuccBB : BB->successors())
3308       if (!validateBlock(SuccBB, "successor"))
3309         return false;
3310     for (const BinaryBasicBlock *LP : BB->landing_pads())
3311       if (!validateBlock(LP, "landing pad"))
3312         return false;
3313     for (const BinaryBasicBlock *Thrower : BB->throwers())
3314       if (!validateBlock(Thrower, "thrower"))
3315         return false;
3316   }
3317 
3318   for (const BinaryBasicBlock *BB : BasicBlocks) {
3319     std::unordered_set<const BinaryBasicBlock *> BBLandingPads;
3320     for (const BinaryBasicBlock *LP : BB->landing_pads()) {
3321       if (BBLandingPads.count(LP)) {
3322         BC.errs() << "BOLT-ERROR: duplicate landing pad detected in"
3323                   << BB->getName() << " in function " << *this << '\n';
3324         return false;
3325       }
3326       BBLandingPads.insert(LP);
3327     }
3328 
3329     std::unordered_set<const BinaryBasicBlock *> BBThrowers;
3330     for (const BinaryBasicBlock *Thrower : BB->throwers()) {
3331       if (BBThrowers.count(Thrower)) {
3332         BC.errs() << "BOLT-ERROR: duplicate thrower detected in"
3333                   << BB->getName() << " in function " << *this << '\n';
3334         return false;
3335       }
3336       BBThrowers.insert(Thrower);
3337     }
3338 
3339     for (const BinaryBasicBlock *LPBlock : BB->landing_pads()) {
3340       if (!llvm::is_contained(LPBlock->throwers(), BB)) {
3341         BC.errs() << "BOLT-ERROR: inconsistent landing pad detected in "
3342                   << *this << ": " << BB->getName()
3343                   << " is in LandingPads but not in " << LPBlock->getName()
3344                   << " Throwers\n";
3345         return false;
3346       }
3347     }
3348     for (const BinaryBasicBlock *Thrower : BB->throwers()) {
3349       if (!llvm::is_contained(Thrower->landing_pads(), BB)) {
3350         BC.errs() << "BOLT-ERROR: inconsistent thrower detected in " << *this
3351                   << ": " << BB->getName() << " is in Throwers list but not in "
3352                   << Thrower->getName() << " LandingPads\n";
3353         return false;
3354       }
3355     }
3356   }
3357 
3358   return true;
3359 }
3360 
3361 void BinaryFunction::fixBranches() {
3362   auto &MIB = BC.MIB;
3363   MCContext *Ctx = BC.Ctx.get();
3364 
3365   for (BinaryBasicBlock *BB : BasicBlocks) {
3366     const MCSymbol *TBB = nullptr;
3367     const MCSymbol *FBB = nullptr;
3368     MCInst *CondBranch = nullptr;
3369     MCInst *UncondBranch = nullptr;
3370     if (!BB->analyzeBranch(TBB, FBB, CondBranch, UncondBranch))
3371       continue;
3372 
3373     // We will create unconditional branch with correct destination if needed.
3374     if (UncondBranch)
3375       BB->eraseInstruction(BB->findInstruction(UncondBranch));
3376 
3377     // Basic block that follows the current one in the final layout.
3378     const BinaryBasicBlock *const NextBB =
3379         Layout.getBasicBlockAfter(BB, /*IgnoreSplits=*/false);
3380 
3381     if (BB->succ_size() == 1) {
3382       // __builtin_unreachable() could create a conditional branch that
3383       // falls-through into the next function - hence the block will have only
3384       // one valid successor. Since behaviour is undefined - we replace
3385       // the conditional branch with an unconditional if required.
3386       if (CondBranch)
3387         BB->eraseInstruction(BB->findInstruction(CondBranch));
3388       if (BB->getSuccessor() == NextBB)
3389         continue;
3390       BB->addBranchInstruction(BB->getSuccessor());
3391     } else if (BB->succ_size() == 2) {
3392       assert(CondBranch && "conditional branch expected");
3393       const BinaryBasicBlock *TSuccessor = BB->getConditionalSuccessor(true);
3394       const BinaryBasicBlock *FSuccessor = BB->getConditionalSuccessor(false);
3395 
3396       // Eliminate unnecessary conditional branch.
3397       if (TSuccessor == FSuccessor) {
3398         // FIXME: at the moment, we cannot safely remove static key branches.
3399         if (MIB->isDynamicBranch(*CondBranch)) {
3400           if (opts::Verbosity) {
3401             BC.outs()
3402                 << "BOLT-INFO: unable to remove redundant dynamic branch in "
3403                 << *this << '\n';
3404           }
3405           continue;
3406         }
3407 
3408         BB->removeDuplicateConditionalSuccessor(CondBranch);
3409         if (TSuccessor != NextBB)
3410           BB->addBranchInstruction(TSuccessor);
3411         continue;
3412       }
3413 
3414       // Reverse branch condition and swap successors.
3415       auto swapSuccessors = [&]() {
3416         if (!MIB->isReversibleBranch(*CondBranch)) {
3417           if (opts::Verbosity) {
3418             BC.outs() << "BOLT-INFO: unable to swap successors in " << *this
3419                       << '\n';
3420           }
3421           return false;
3422         }
3423         std::swap(TSuccessor, FSuccessor);
3424         BB->swapConditionalSuccessors();
3425         auto L = BC.scopeLock();
3426         MIB->reverseBranchCondition(*CondBranch, TSuccessor->getLabel(), Ctx);
3427         return true;
3428       };
3429 
3430       // Check whether the next block is a "taken" target and try to swap it
3431       // with a "fall-through" target.
3432       if (TSuccessor == NextBB && swapSuccessors())
3433         continue;
3434 
3435       // Update conditional branch destination if needed.
3436       if (MIB->getTargetSymbol(*CondBranch) != TSuccessor->getLabel()) {
3437         auto L = BC.scopeLock();
3438         MIB->replaceBranchTarget(*CondBranch, TSuccessor->getLabel(), Ctx);
3439       }
3440 
3441       // No need for the unconditional branch.
3442       if (FSuccessor == NextBB)
3443         continue;
3444 
3445       if (BC.isX86()) {
3446         // We are going to generate two branches. Check if their targets are in
3447         // the same fragment as this block. If only one target is in the same
3448         // fragment, make it the destination of the conditional branch. There
3449         // is a chance it will be a short branch which takes 4 bytes fewer than
3450         // a long conditional branch. For unconditional branch, the difference
3451         // is 3 bytes.
3452         if (BB->getFragmentNum() != TSuccessor->getFragmentNum() &&
3453             BB->getFragmentNum() == FSuccessor->getFragmentNum())
3454           swapSuccessors();
3455       }
3456 
3457       BB->addBranchInstruction(FSuccessor);
3458     }
3459     // Cases where the number of successors is 0 (block ends with a
3460     // terminator) or more than 2 (switch table) don't require branch
3461     // instruction adjustments.
3462   }
3463   assert((!isSimple() || validateCFG()) &&
3464          "Invalid CFG detected after fixing branches");
3465 }
3466 
3467 void BinaryFunction::propagateGnuArgsSizeInfo(
3468     MCPlusBuilder::AllocatorIdTy AllocId) {
3469   assert(CurrentState == State::Disassembled && "unexpected function state");
3470 
3471   if (!hasEHRanges() || !usesGnuArgsSize())
3472     return;
3473 
3474   // The current value of DW_CFA_GNU_args_size affects all following
3475   // invoke instructions until the next CFI overrides it.
3476   // It is important to iterate basic blocks in the original order when
3477   // assigning the value.
3478   uint64_t CurrentGnuArgsSize = 0;
3479   for (BinaryBasicBlock *BB : BasicBlocks) {
3480     for (auto II = BB->begin(); II != BB->end();) {
3481       MCInst &Instr = *II;
3482       if (BC.MIB->isCFI(Instr)) {
3483         const MCCFIInstruction *CFI = getCFIFor(Instr);
3484         if (CFI->getOperation() == MCCFIInstruction::OpGnuArgsSize) {
3485           CurrentGnuArgsSize = CFI->getOffset();
3486           // Delete DW_CFA_GNU_args_size instructions and only regenerate
3487           // during the final code emission. The information is embedded
3488           // inside call instructions.
3489           II = BB->erasePseudoInstruction(II);
3490           continue;
3491         }
3492       } else if (BC.MIB->isInvoke(Instr)) {
3493         // Add the value of GNU_args_size as an extra operand to invokes.
3494         BC.MIB->addGnuArgsSize(Instr, CurrentGnuArgsSize);
3495       }
3496       ++II;
3497     }
3498   }
3499 }
3500 
3501 void BinaryFunction::postProcessBranches() {
3502   if (!isSimple())
3503     return;
3504   for (BinaryBasicBlock &BB : blocks()) {
3505     auto LastInstrRI = BB.getLastNonPseudo();
3506     if (BB.succ_size() == 1) {
3507       if (LastInstrRI != BB.rend() &&
3508           BC.MIB->isConditionalBranch(*LastInstrRI)) {
3509         // __builtin_unreachable() could create a conditional branch that
3510         // falls-through into the next function - hence the block will have only
3511         // one valid successor. Such behaviour is undefined and thus we remove
3512         // the conditional branch while leaving a valid successor.
3513         BB.eraseInstruction(std::prev(LastInstrRI.base()));
3514         LLVM_DEBUG(dbgs() << "BOLT-DEBUG: erasing conditional branch in "
3515                           << BB.getName() << " in function " << *this << '\n');
3516       }
3517     } else if (BB.succ_size() == 0) {
3518       // Ignore unreachable basic blocks.
3519       if (BB.pred_size() == 0 || BB.isLandingPad())
3520         continue;
3521 
3522       // If it's the basic block that does not end up with a terminator - we
3523       // insert a return instruction unless it's a call instruction.
3524       if (LastInstrRI == BB.rend()) {
3525         LLVM_DEBUG(
3526             dbgs() << "BOLT-DEBUG: at least one instruction expected in BB "
3527                    << BB.getName() << " in function " << *this << '\n');
3528         continue;
3529       }
3530       if (!BC.MIB->isTerminator(*LastInstrRI) &&
3531           !BC.MIB->isCall(*LastInstrRI)) {
3532         LLVM_DEBUG(dbgs() << "BOLT-DEBUG: adding return to basic block "
3533                           << BB.getName() << " in function " << *this << '\n');
3534         MCInst ReturnInstr;
3535         BC.MIB->createReturn(ReturnInstr);
3536         BB.addInstruction(ReturnInstr);
3537       }
3538     }
3539   }
3540   assert(validateCFG() && "invalid CFG");
3541 }
3542 
3543 MCSymbol *BinaryFunction::addEntryPointAtOffset(uint64_t Offset) {
3544   assert(Offset && "cannot add primary entry point");
3545   assert(CurrentState == State::Empty || CurrentState == State::Disassembled);
3546 
3547   const uint64_t EntryPointAddress = getAddress() + Offset;
3548   MCSymbol *LocalSymbol = getOrCreateLocalLabel(EntryPointAddress);
3549 
3550   MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(LocalSymbol);
3551   if (EntrySymbol)
3552     return EntrySymbol;
3553 
3554   if (BinaryData *EntryBD = BC.getBinaryDataAtAddress(EntryPointAddress)) {
3555     EntrySymbol = EntryBD->getSymbol();
3556   } else {
3557     EntrySymbol = BC.getOrCreateGlobalSymbol(
3558         EntryPointAddress, Twine("__ENTRY_") + getOneName() + "@");
3559   }
3560   SecondaryEntryPoints[LocalSymbol] = EntrySymbol;
3561 
3562   BC.setSymbolToFunctionMap(EntrySymbol, this);
3563 
3564   return EntrySymbol;
3565 }
3566 
3567 MCSymbol *BinaryFunction::addEntryPoint(const BinaryBasicBlock &BB) {
3568   assert(CurrentState == State::CFG &&
3569          "basic block can be added as an entry only in a function with CFG");
3570 
3571   if (&BB == BasicBlocks.front())
3572     return getSymbol();
3573 
3574   MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(BB);
3575   if (EntrySymbol)
3576     return EntrySymbol;
3577 
3578   EntrySymbol =
3579       BC.Ctx->getOrCreateSymbol("__ENTRY_" + BB.getLabel()->getName());
3580 
3581   SecondaryEntryPoints[BB.getLabel()] = EntrySymbol;
3582 
3583   BC.setSymbolToFunctionMap(EntrySymbol, this);
3584 
3585   return EntrySymbol;
3586 }
3587 
3588 MCSymbol *BinaryFunction::getSymbolForEntryID(uint64_t EntryID) {
3589   if (EntryID == 0)
3590     return getSymbol();
3591 
3592   if (!isMultiEntry())
3593     return nullptr;
3594 
3595   uint64_t NumEntries = 1;
3596   if (hasCFG()) {
3597     for (BinaryBasicBlock *BB : BasicBlocks) {
3598       MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(*BB);
3599       if (!EntrySymbol)
3600         continue;
3601       if (NumEntries == EntryID)
3602         return EntrySymbol;
3603       ++NumEntries;
3604     }
3605   } else {
3606     for (std::pair<const uint32_t, MCSymbol *> &KV : Labels) {
3607       MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(KV.second);
3608       if (!EntrySymbol)
3609         continue;
3610       if (NumEntries == EntryID)
3611         return EntrySymbol;
3612       ++NumEntries;
3613     }
3614   }
3615 
3616   return nullptr;
3617 }
3618 
3619 uint64_t BinaryFunction::getEntryIDForSymbol(const MCSymbol *Symbol) const {
3620   if (!isMultiEntry())
3621     return 0;
3622 
3623   for (const MCSymbol *FunctionSymbol : getSymbols())
3624     if (FunctionSymbol == Symbol)
3625       return 0;
3626 
3627   // Check all secondary entries available as either basic blocks or lables.
3628   uint64_t NumEntries = 1;
3629   for (const BinaryBasicBlock *BB : BasicBlocks) {
3630     MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(*BB);
3631     if (!EntrySymbol)
3632       continue;
3633     if (EntrySymbol == Symbol)
3634       return NumEntries;
3635     ++NumEntries;
3636   }
3637   NumEntries = 1;
3638   for (const std::pair<const uint32_t, MCSymbol *> &KV : Labels) {
3639     MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(KV.second);
3640     if (!EntrySymbol)
3641       continue;
3642     if (EntrySymbol == Symbol)
3643       return NumEntries;
3644     ++NumEntries;
3645   }
3646 
3647   llvm_unreachable("symbol not found");
3648 }
3649 
3650 bool BinaryFunction::forEachEntryPoint(EntryPointCallbackTy Callback) const {
3651   bool Status = Callback(0, getSymbol());
3652   if (!isMultiEntry())
3653     return Status;
3654 
3655   for (const std::pair<const uint32_t, MCSymbol *> &KV : Labels) {
3656     if (!Status)
3657       break;
3658 
3659     MCSymbol *EntrySymbol = getSecondaryEntryPointSymbol(KV.second);
3660     if (!EntrySymbol)
3661       continue;
3662 
3663     Status = Callback(KV.first, EntrySymbol);
3664   }
3665 
3666   return Status;
3667 }
3668 
3669 BinaryFunction::BasicBlockListType BinaryFunction::dfs() const {
3670   BasicBlockListType DFS;
3671   std::stack<BinaryBasicBlock *> Stack;
3672   std::set<BinaryBasicBlock *> Visited;
3673 
3674   // Push entry points to the stack in reverse order.
3675   //
3676   // NB: we rely on the original order of entries to match.
3677   SmallVector<BinaryBasicBlock *> EntryPoints;
3678   llvm::copy_if(BasicBlocks, std::back_inserter(EntryPoints),
3679           [&](const BinaryBasicBlock *const BB) { return isEntryPoint(*BB); });
3680   // Sort entry points by their offset to make sure we got them in the right
3681   // order.
3682   llvm::stable_sort(EntryPoints, [](const BinaryBasicBlock *const A,
3683                               const BinaryBasicBlock *const B) {
3684     return A->getOffset() < B->getOffset();
3685   });
3686   for (BinaryBasicBlock *const BB : reverse(EntryPoints))
3687     Stack.push(BB);
3688 
3689   while (!Stack.empty()) {
3690     BinaryBasicBlock *BB = Stack.top();
3691     Stack.pop();
3692 
3693     if (!Visited.insert(BB).second)
3694       continue;
3695     DFS.push_back(BB);
3696 
3697     for (BinaryBasicBlock *SuccBB : BB->landing_pads()) {
3698       Stack.push(SuccBB);
3699     }
3700 
3701     const MCSymbol *TBB = nullptr;
3702     const MCSymbol *FBB = nullptr;
3703     MCInst *CondBranch = nullptr;
3704     MCInst *UncondBranch = nullptr;
3705     if (BB->analyzeBranch(TBB, FBB, CondBranch, UncondBranch) && CondBranch &&
3706         BB->succ_size() == 2) {
3707       if (BC.MIB->getCanonicalBranchCondCode(BC.MIB->getCondCode(
3708               *CondBranch)) == BC.MIB->getCondCode(*CondBranch)) {
3709         Stack.push(BB->getConditionalSuccessor(true));
3710         Stack.push(BB->getConditionalSuccessor(false));
3711       } else {
3712         Stack.push(BB->getConditionalSuccessor(false));
3713         Stack.push(BB->getConditionalSuccessor(true));
3714       }
3715     } else {
3716       for (BinaryBasicBlock *SuccBB : BB->successors()) {
3717         Stack.push(SuccBB);
3718       }
3719     }
3720   }
3721 
3722   return DFS;
3723 }
3724 
3725 size_t BinaryFunction::computeHash(bool UseDFS, HashFunction HashFunction,
3726                                    OperandHashFuncTy OperandHashFunc) const {
3727   LLVM_DEBUG({
3728     dbgs() << "BOLT-DEBUG: computeHash " << getPrintName() << ' '
3729            << (UseDFS ? "dfs" : "bin") << " order "
3730            << (HashFunction == HashFunction::StdHash ? "std::hash" : "xxh3")
3731            << '\n';
3732   });
3733 
3734   if (size() == 0)
3735     return 0;
3736 
3737   assert(hasCFG() && "function is expected to have CFG");
3738 
3739   SmallVector<const BinaryBasicBlock *, 0> Order;
3740   if (UseDFS)
3741     llvm::copy(dfs(), std::back_inserter(Order));
3742   else
3743     llvm::copy(Layout.blocks(), std::back_inserter(Order));
3744 
3745   // The hash is computed by creating a string of all instruction opcodes and
3746   // possibly their operands and then hashing that string with std::hash.
3747   std::string HashString;
3748   for (const BinaryBasicBlock *BB : Order)
3749     HashString.append(hashBlock(BC, *BB, OperandHashFunc));
3750 
3751   switch (HashFunction) {
3752   case HashFunction::StdHash:
3753     return Hash = std::hash<std::string>{}(HashString);
3754   case HashFunction::XXH3:
3755     return Hash = llvm::xxh3_64bits(HashString);
3756   }
3757   llvm_unreachable("Unhandled HashFunction");
3758 }
3759 
3760 void BinaryFunction::insertBasicBlocks(
3761     BinaryBasicBlock *Start,
3762     std::vector<std::unique_ptr<BinaryBasicBlock>> &&NewBBs,
3763     const bool UpdateLayout, const bool UpdateCFIState,
3764     const bool RecomputeLandingPads) {
3765   const int64_t StartIndex = Start ? getIndex(Start) : -1LL;
3766   const size_t NumNewBlocks = NewBBs.size();
3767 
3768   BasicBlocks.insert(BasicBlocks.begin() + (StartIndex + 1), NumNewBlocks,
3769                      nullptr);
3770 
3771   int64_t I = StartIndex + 1;
3772   for (std::unique_ptr<BinaryBasicBlock> &BB : NewBBs) {
3773     assert(!BasicBlocks[I]);
3774     BasicBlocks[I++] = BB.release();
3775   }
3776 
3777   if (RecomputeLandingPads)
3778     recomputeLandingPads();
3779   else
3780     updateBBIndices(0);
3781 
3782   if (UpdateLayout)
3783     updateLayout(Start, NumNewBlocks);
3784 
3785   if (UpdateCFIState)
3786     updateCFIState(Start, NumNewBlocks);
3787 }
3788 
3789 BinaryFunction::iterator BinaryFunction::insertBasicBlocks(
3790     BinaryFunction::iterator StartBB,
3791     std::vector<std::unique_ptr<BinaryBasicBlock>> &&NewBBs,
3792     const bool UpdateLayout, const bool UpdateCFIState,
3793     const bool RecomputeLandingPads) {
3794   const unsigned StartIndex = getIndex(&*StartBB);
3795   const size_t NumNewBlocks = NewBBs.size();
3796 
3797   BasicBlocks.insert(BasicBlocks.begin() + StartIndex + 1, NumNewBlocks,
3798                      nullptr);
3799   auto RetIter = BasicBlocks.begin() + StartIndex + 1;
3800 
3801   unsigned I = StartIndex + 1;
3802   for (std::unique_ptr<BinaryBasicBlock> &BB : NewBBs) {
3803     assert(!BasicBlocks[I]);
3804     BasicBlocks[I++] = BB.release();
3805   }
3806 
3807   if (RecomputeLandingPads)
3808     recomputeLandingPads();
3809   else
3810     updateBBIndices(0);
3811 
3812   if (UpdateLayout)
3813     updateLayout(*std::prev(RetIter), NumNewBlocks);
3814 
3815   if (UpdateCFIState)
3816     updateCFIState(*std::prev(RetIter), NumNewBlocks);
3817 
3818   return RetIter;
3819 }
3820 
3821 void BinaryFunction::updateBBIndices(const unsigned StartIndex) {
3822   for (unsigned I = StartIndex; I < BasicBlocks.size(); ++I)
3823     BasicBlocks[I]->Index = I;
3824 }
3825 
3826 void BinaryFunction::updateCFIState(BinaryBasicBlock *Start,
3827                                     const unsigned NumNewBlocks) {
3828   const int32_t CFIState = Start->getCFIStateAtExit();
3829   const unsigned StartIndex = getIndex(Start) + 1;
3830   for (unsigned I = 0; I < NumNewBlocks; ++I)
3831     BasicBlocks[StartIndex + I]->setCFIState(CFIState);
3832 }
3833 
3834 void BinaryFunction::updateLayout(BinaryBasicBlock *Start,
3835                                   const unsigned NumNewBlocks) {
3836   BasicBlockListType::iterator Begin;
3837   BasicBlockListType::iterator End;
3838 
3839   // If start not provided copy new blocks from the beginning of BasicBlocks
3840   if (!Start) {
3841     Begin = BasicBlocks.begin();
3842     End = BasicBlocks.begin() + NumNewBlocks;
3843   } else {
3844     unsigned StartIndex = getIndex(Start);
3845     Begin = std::next(BasicBlocks.begin(), StartIndex + 1);
3846     End = std::next(BasicBlocks.begin(), StartIndex + NumNewBlocks + 1);
3847   }
3848 
3849   // Insert new blocks in the layout immediately after Start.
3850   Layout.insertBasicBlocks(Start, {Begin, End});
3851   Layout.updateLayoutIndices();
3852 }
3853 
3854 bool BinaryFunction::checkForAmbiguousJumpTables() {
3855   SmallSet<uint64_t, 4> JumpTables;
3856   for (BinaryBasicBlock *&BB : BasicBlocks) {
3857     for (MCInst &Inst : *BB) {
3858       if (!BC.MIB->isIndirectBranch(Inst))
3859         continue;
3860       uint64_t JTAddress = BC.MIB->getJumpTable(Inst);
3861       if (!JTAddress)
3862         continue;
3863       // This address can be inside another jump table, but we only consider
3864       // it ambiguous when the same start address is used, not the same JT
3865       // object.
3866       if (!JumpTables.count(JTAddress)) {
3867         JumpTables.insert(JTAddress);
3868         continue;
3869       }
3870       return true;
3871     }
3872   }
3873   return false;
3874 }
3875 
3876 void BinaryFunction::disambiguateJumpTables(
3877     MCPlusBuilder::AllocatorIdTy AllocId) {
3878   assert((opts::JumpTables != JTS_BASIC && isSimple()) || !BC.HasRelocations);
3879   SmallPtrSet<JumpTable *, 4> JumpTables;
3880   for (BinaryBasicBlock *&BB : BasicBlocks) {
3881     for (MCInst &Inst : *BB) {
3882       if (!BC.MIB->isIndirectBranch(Inst))
3883         continue;
3884       JumpTable *JT = getJumpTable(Inst);
3885       if (!JT)
3886         continue;
3887       if (JumpTables.insert(JT).second)
3888         continue;
3889       // This instruction is an indirect jump using a jump table, but it is
3890       // using the same jump table of another jump. Try all our tricks to
3891       // extract the jump table symbol and make it point to a new, duplicated JT
3892       MCPhysReg BaseReg1;
3893       uint64_t Scale;
3894       const MCSymbol *Target;
3895       // In case we match if our first matcher, first instruction is the one to
3896       // patch
3897       MCInst *JTLoadInst = &Inst;
3898       // Try a standard indirect jump matcher, scale 8
3899       std::unique_ptr<MCPlusBuilder::MCInstMatcher> IndJmpMatcher =
3900           BC.MIB->matchIndJmp(BC.MIB->matchReg(BaseReg1),
3901                               BC.MIB->matchImm(Scale), BC.MIB->matchReg(),
3902                               /*Offset=*/BC.MIB->matchSymbol(Target));
3903       if (!IndJmpMatcher->match(
3904               *BC.MRI, *BC.MIB,
3905               MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1) ||
3906           BaseReg1 != BC.MIB->getNoRegister() || Scale != 8) {
3907         MCPhysReg BaseReg2;
3908         uint64_t Offset;
3909         // Standard JT matching failed. Trying now:
3910         //     movq  "jt.2397/1"(,%rax,8), %rax
3911         //     jmpq  *%rax
3912         std::unique_ptr<MCPlusBuilder::MCInstMatcher> LoadMatcherOwner =
3913             BC.MIB->matchLoad(BC.MIB->matchReg(BaseReg1),
3914                               BC.MIB->matchImm(Scale), BC.MIB->matchReg(),
3915                               /*Offset=*/BC.MIB->matchSymbol(Target));
3916         MCPlusBuilder::MCInstMatcher *LoadMatcher = LoadMatcherOwner.get();
3917         std::unique_ptr<MCPlusBuilder::MCInstMatcher> IndJmpMatcher2 =
3918             BC.MIB->matchIndJmp(std::move(LoadMatcherOwner));
3919         if (!IndJmpMatcher2->match(
3920                 *BC.MRI, *BC.MIB,
3921                 MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1) ||
3922             BaseReg1 != BC.MIB->getNoRegister() || Scale != 8) {
3923           // JT matching failed. Trying now:
3924           // PIC-style matcher, scale 4
3925           //    addq    %rdx, %rsi
3926           //    addq    %rdx, %rdi
3927           //    leaq    DATAat0x402450(%rip), %r11
3928           //    movslq  (%r11,%rdx,4), %rcx
3929           //    addq    %r11, %rcx
3930           //    jmpq    *%rcx # JUMPTABLE @0x402450
3931           std::unique_ptr<MCPlusBuilder::MCInstMatcher> PICIndJmpMatcher =
3932               BC.MIB->matchIndJmp(BC.MIB->matchAdd(
3933                   BC.MIB->matchReg(BaseReg1),
3934                   BC.MIB->matchLoad(BC.MIB->matchReg(BaseReg2),
3935                                     BC.MIB->matchImm(Scale), BC.MIB->matchReg(),
3936                                     BC.MIB->matchImm(Offset))));
3937           std::unique_ptr<MCPlusBuilder::MCInstMatcher> LEAMatcherOwner =
3938               BC.MIB->matchLoadAddr(BC.MIB->matchSymbol(Target));
3939           MCPlusBuilder::MCInstMatcher *LEAMatcher = LEAMatcherOwner.get();
3940           std::unique_ptr<MCPlusBuilder::MCInstMatcher> PICBaseAddrMatcher =
3941               BC.MIB->matchIndJmp(BC.MIB->matchAdd(std::move(LEAMatcherOwner),
3942                                                    BC.MIB->matchAnyOperand()));
3943           if (!PICIndJmpMatcher->match(
3944                   *BC.MRI, *BC.MIB,
3945                   MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1) ||
3946               Scale != 4 || BaseReg1 != BaseReg2 || Offset != 0 ||
3947               !PICBaseAddrMatcher->match(
3948                   *BC.MRI, *BC.MIB,
3949                   MutableArrayRef<MCInst>(&*BB->begin(), &Inst + 1), -1)) {
3950             llvm_unreachable("Failed to extract jump table base");
3951             continue;
3952           }
3953           // Matched PIC, identify the instruction with the reference to the JT
3954           JTLoadInst = LEAMatcher->CurInst;
3955         } else {
3956           // Matched non-PIC
3957           JTLoadInst = LoadMatcher->CurInst;
3958         }
3959       }
3960 
3961       uint64_t NewJumpTableID = 0;
3962       const MCSymbol *NewJTLabel;
3963       std::tie(NewJumpTableID, NewJTLabel) =
3964           BC.duplicateJumpTable(*this, JT, Target);
3965       {
3966         auto L = BC.scopeLock();
3967         BC.MIB->replaceMemOperandDisp(*JTLoadInst, NewJTLabel, BC.Ctx.get());
3968       }
3969       // We use a unique ID with the high bit set as address for this "injected"
3970       // jump table (not originally in the input binary).
3971       BC.MIB->setJumpTable(Inst, NewJumpTableID, 0, AllocId);
3972     }
3973   }
3974 }
3975 
3976 bool BinaryFunction::replaceJumpTableEntryIn(BinaryBasicBlock *BB,
3977                                              BinaryBasicBlock *OldDest,
3978                                              BinaryBasicBlock *NewDest) {
3979   MCInst *Instr = BB->getLastNonPseudoInstr();
3980   if (!Instr || !BC.MIB->isIndirectBranch(*Instr))
3981     return false;
3982   uint64_t JTAddress = BC.MIB->getJumpTable(*Instr);
3983   assert(JTAddress && "Invalid jump table address");
3984   JumpTable *JT = getJumpTableContainingAddress(JTAddress);
3985   assert(JT && "No jump table structure for this indirect branch");
3986   bool Patched = JT->replaceDestination(JTAddress, OldDest->getLabel(),
3987                                         NewDest->getLabel());
3988   (void)Patched;
3989   assert(Patched && "Invalid entry to be replaced in jump table");
3990   return true;
3991 }
3992 
3993 BinaryBasicBlock *BinaryFunction::splitEdge(BinaryBasicBlock *From,
3994                                             BinaryBasicBlock *To) {
3995   // Create intermediate BB
3996   MCSymbol *Tmp;
3997   {
3998     auto L = BC.scopeLock();
3999     Tmp = BC.Ctx->createNamedTempSymbol("SplitEdge");
4000   }
4001   // Link new BBs to the original input offset of the From BB, so we can map
4002   // samples recorded in new BBs back to the original BB seem in the input
4003   // binary (if using BAT)
4004   std::unique_ptr<BinaryBasicBlock> NewBB = createBasicBlock(Tmp);
4005   NewBB->setOffset(From->getInputOffset());
4006   BinaryBasicBlock *NewBBPtr = NewBB.get();
4007 
4008   // Update "From" BB
4009   auto I = From->succ_begin();
4010   auto BI = From->branch_info_begin();
4011   for (; I != From->succ_end(); ++I) {
4012     if (*I == To)
4013       break;
4014     ++BI;
4015   }
4016   assert(I != From->succ_end() && "Invalid CFG edge in splitEdge!");
4017   uint64_t OrigCount = BI->Count;
4018   uint64_t OrigMispreds = BI->MispredictedCount;
4019   replaceJumpTableEntryIn(From, To, NewBBPtr);
4020   From->replaceSuccessor(To, NewBBPtr, OrigCount, OrigMispreds);
4021 
4022   NewBB->addSuccessor(To, OrigCount, OrigMispreds);
4023   NewBB->setExecutionCount(OrigCount);
4024   NewBB->setIsCold(From->isCold());
4025 
4026   // Update CFI and BB layout with new intermediate BB
4027   std::vector<std::unique_ptr<BinaryBasicBlock>> NewBBs;
4028   NewBBs.emplace_back(std::move(NewBB));
4029   insertBasicBlocks(From, std::move(NewBBs), true, true,
4030                     /*RecomputeLandingPads=*/false);
4031   return NewBBPtr;
4032 }
4033 
4034 void BinaryFunction::deleteConservativeEdges() {
4035   // Our goal is to aggressively remove edges from the CFG that we believe are
4036   // wrong. This is used for instrumentation, where it is safe to remove
4037   // fallthrough edges because we won't reorder blocks.
4038   for (auto I = BasicBlocks.begin(), E = BasicBlocks.end(); I != E; ++I) {
4039     BinaryBasicBlock *BB = *I;
4040     if (BB->succ_size() != 1 || BB->size() == 0)
4041       continue;
4042 
4043     auto NextBB = std::next(I);
4044     MCInst *Last = BB->getLastNonPseudoInstr();
4045     // Fallthrough is a landing pad? Delete this edge (as long as we don't
4046     // have a direct jump to it)
4047     if ((*BB->succ_begin())->isLandingPad() && NextBB != E &&
4048         *BB->succ_begin() == *NextBB && Last && !BC.MIB->isBranch(*Last)) {
4049       BB->removeAllSuccessors();
4050       continue;
4051     }
4052 
4053     // Look for suspicious calls at the end of BB where gcc may optimize it and
4054     // remove the jump to the epilogue when it knows the call won't return.
4055     if (!Last || !BC.MIB->isCall(*Last))
4056       continue;
4057 
4058     const MCSymbol *CalleeSymbol = BC.MIB->getTargetSymbol(*Last);
4059     if (!CalleeSymbol)
4060       continue;
4061 
4062     StringRef CalleeName = CalleeSymbol->getName();
4063     if (CalleeName != "__cxa_throw@PLT" && CalleeName != "_Unwind_Resume@PLT" &&
4064         CalleeName != "__cxa_rethrow@PLT" && CalleeName != "exit@PLT" &&
4065         CalleeName != "abort@PLT")
4066       continue;
4067 
4068     BB->removeAllSuccessors();
4069   }
4070 }
4071 
4072 bool BinaryFunction::isSymbolValidInScope(const SymbolRef &Symbol,
4073                                           uint64_t SymbolSize) const {
4074   // If this symbol is in a different section from the one where the
4075   // function symbol is, don't consider it as valid.
4076   if (!getOriginSection()->containsAddress(
4077           cantFail(Symbol.getAddress(), "cannot get symbol address")))
4078     return false;
4079 
4080   // Some symbols are tolerated inside function bodies, others are not.
4081   // The real function boundaries may not be known at this point.
4082   if (BC.isMarker(Symbol))
4083     return true;
4084 
4085   // It's okay to have a zero-sized symbol in the middle of non-zero-sized
4086   // function.
4087   if (SymbolSize == 0 && containsAddress(cantFail(Symbol.getAddress())))
4088     return true;
4089 
4090   if (cantFail(Symbol.getType()) != SymbolRef::ST_Unknown)
4091     return false;
4092 
4093   if (cantFail(Symbol.getFlags()) & SymbolRef::SF_Global)
4094     return false;
4095 
4096   return true;
4097 }
4098 
4099 void BinaryFunction::adjustExecutionCount(uint64_t Count) {
4100   if (getKnownExecutionCount() == 0 || Count == 0)
4101     return;
4102 
4103   if (ExecutionCount < Count)
4104     Count = ExecutionCount;
4105 
4106   double AdjustmentRatio = ((double)ExecutionCount - Count) / ExecutionCount;
4107   if (AdjustmentRatio < 0.0)
4108     AdjustmentRatio = 0.0;
4109 
4110   for (BinaryBasicBlock &BB : blocks())
4111     BB.adjustExecutionCount(AdjustmentRatio);
4112 
4113   ExecutionCount -= Count;
4114 }
4115 
4116 BinaryFunction::~BinaryFunction() {
4117   for (BinaryBasicBlock *BB : BasicBlocks)
4118     delete BB;
4119   for (BinaryBasicBlock *BB : DeletedBasicBlocks)
4120     delete BB;
4121 }
4122 
4123 void BinaryFunction::constructDomTree() {
4124   BDT.reset(new BinaryDominatorTree);
4125   BDT->recalculate(*this);
4126 }
4127 
4128 void BinaryFunction::calculateLoopInfo() {
4129   if (!hasDomTree())
4130     constructDomTree();
4131   // Discover loops.
4132   BLI.reset(new BinaryLoopInfo());
4133   BLI->analyze(getDomTree());
4134 
4135   // Traverse discovered loops and add depth and profile information.
4136   std::stack<BinaryLoop *> St;
4137   for (auto I = BLI->begin(), E = BLI->end(); I != E; ++I) {
4138     St.push(*I);
4139     ++BLI->OuterLoops;
4140   }
4141 
4142   while (!St.empty()) {
4143     BinaryLoop *L = St.top();
4144     St.pop();
4145     ++BLI->TotalLoops;
4146     BLI->MaximumDepth = std::max(L->getLoopDepth(), BLI->MaximumDepth);
4147 
4148     // Add nested loops in the stack.
4149     for (BinaryLoop::iterator I = L->begin(), E = L->end(); I != E; ++I)
4150       St.push(*I);
4151 
4152     // Skip if no valid profile is found.
4153     if (!hasValidProfile()) {
4154       L->EntryCount = COUNT_NO_PROFILE;
4155       L->ExitCount = COUNT_NO_PROFILE;
4156       L->TotalBackEdgeCount = COUNT_NO_PROFILE;
4157       continue;
4158     }
4159 
4160     // Compute back edge count.
4161     SmallVector<BinaryBasicBlock *, 1> Latches;
4162     L->getLoopLatches(Latches);
4163 
4164     for (BinaryBasicBlock *Latch : Latches) {
4165       auto BI = Latch->branch_info_begin();
4166       for (BinaryBasicBlock *Succ : Latch->successors()) {
4167         if (Succ == L->getHeader()) {
4168           assert(BI->Count != BinaryBasicBlock::COUNT_NO_PROFILE &&
4169                  "profile data not found");
4170           L->TotalBackEdgeCount += BI->Count;
4171         }
4172         ++BI;
4173       }
4174     }
4175 
4176     // Compute entry count.
4177     L->EntryCount = L->getHeader()->getExecutionCount() - L->TotalBackEdgeCount;
4178 
4179     // Compute exit count.
4180     SmallVector<BinaryLoop::Edge, 1> ExitEdges;
4181     L->getExitEdges(ExitEdges);
4182     for (BinaryLoop::Edge &Exit : ExitEdges) {
4183       const BinaryBasicBlock *Exiting = Exit.first;
4184       const BinaryBasicBlock *ExitTarget = Exit.second;
4185       auto BI = Exiting->branch_info_begin();
4186       for (BinaryBasicBlock *Succ : Exiting->successors()) {
4187         if (Succ == ExitTarget) {
4188           assert(BI->Count != BinaryBasicBlock::COUNT_NO_PROFILE &&
4189                  "profile data not found");
4190           L->ExitCount += BI->Count;
4191         }
4192         ++BI;
4193       }
4194     }
4195   }
4196 }
4197 
4198 void BinaryFunction::updateOutputValues(const BOLTLinker &Linker) {
4199   if (!isEmitted()) {
4200     assert(!isInjected() && "injected function should be emitted");
4201     setOutputAddress(getAddress());
4202     setOutputSize(getSize());
4203     return;
4204   }
4205 
4206   const auto SymbolInfo = Linker.lookupSymbolInfo(getSymbol()->getName());
4207   assert(SymbolInfo && "Cannot find function entry symbol");
4208   setOutputAddress(SymbolInfo->Address);
4209   setOutputSize(SymbolInfo->Size);
4210 
4211   if (BC.HasRelocations || isInjected()) {
4212     if (hasConstantIsland()) {
4213       const auto DataAddress =
4214           Linker.lookupSymbol(getFunctionConstantIslandLabel()->getName());
4215       assert(DataAddress && "Cannot find function CI symbol");
4216       setOutputDataAddress(*DataAddress);
4217       for (auto It : Islands->Offsets) {
4218         const uint64_t OldOffset = It.first;
4219         BinaryData *BD = BC.getBinaryDataAtAddress(getAddress() + OldOffset);
4220         if (!BD)
4221           continue;
4222 
4223         MCSymbol *Symbol = It.second;
4224         const auto NewAddress = Linker.lookupSymbol(Symbol->getName());
4225         assert(NewAddress && "Cannot find CI symbol");
4226         auto &Section = *getCodeSection();
4227         const auto NewOffset = *NewAddress - Section.getOutputAddress();
4228         BD->setOutputLocation(Section, NewOffset);
4229       }
4230     }
4231     if (isSplit()) {
4232       for (FunctionFragment &FF : getLayout().getSplitFragments()) {
4233         ErrorOr<BinarySection &> ColdSection =
4234             getCodeSection(FF.getFragmentNum());
4235         // If fragment is empty, cold section might not exist
4236         if (FF.empty() && ColdSection.getError())
4237           continue;
4238 
4239         const MCSymbol *ColdStartSymbol = getSymbol(FF.getFragmentNum());
4240         // If fragment is empty, symbol might have not been emitted
4241         if (FF.empty() && (!ColdStartSymbol || !ColdStartSymbol->isDefined()) &&
4242             !hasConstantIsland())
4243           continue;
4244         assert(ColdStartSymbol && ColdStartSymbol->isDefined() &&
4245                "split function should have defined cold symbol");
4246         const auto ColdStartSymbolInfo =
4247             Linker.lookupSymbolInfo(ColdStartSymbol->getName());
4248         assert(ColdStartSymbolInfo && "Cannot find cold start symbol");
4249         FF.setAddress(ColdStartSymbolInfo->Address);
4250         FF.setImageSize(ColdStartSymbolInfo->Size);
4251         if (hasConstantIsland()) {
4252           const auto DataAddress = Linker.lookupSymbol(
4253               getFunctionColdConstantIslandLabel()->getName());
4254           assert(DataAddress && "Cannot find cold CI symbol");
4255           setOutputColdDataAddress(*DataAddress);
4256         }
4257       }
4258     }
4259   }
4260 
4261   // Update basic block output ranges for the debug info, if we have
4262   // secondary entry points in the symbol table to update or if writing BAT.
4263   if (!requiresAddressMap())
4264     return;
4265 
4266   // AArch64 may have functions that only contains a constant island (no code).
4267   if (getLayout().block_empty())
4268     return;
4269 
4270   for (FunctionFragment &FF : getLayout().fragments()) {
4271     if (FF.empty())
4272       continue;
4273 
4274     const uint64_t FragmentBaseAddress =
4275         getCodeSection(isSimple() ? FF.getFragmentNum() : FragmentNum::main())
4276             ->getOutputAddress();
4277 
4278     BinaryBasicBlock *PrevBB = nullptr;
4279     for (BinaryBasicBlock *const BB : FF) {
4280       assert(BB->getLabel()->isDefined() && "symbol should be defined");
4281       if (!BC.HasRelocations) {
4282         if (BB->isSplit())
4283           assert(FragmentBaseAddress == FF.getAddress());
4284         else
4285           assert(FragmentBaseAddress == getOutputAddress());
4286         (void)FragmentBaseAddress;
4287       }
4288 
4289       // Injected functions likely will fail lookup, as they have no
4290       // input range. Just assign the BB the output address of the
4291       // function.
4292       auto MaybeBBAddress = BC.getIOAddressMap().lookup(BB->getLabel());
4293       const uint64_t BBAddress = MaybeBBAddress  ? *MaybeBBAddress
4294                                  : BB->isSplit() ? FF.getAddress()
4295                                                  : getOutputAddress();
4296       BB->setOutputStartAddress(BBAddress);
4297 
4298       if (PrevBB) {
4299         assert(PrevBB->getOutputAddressRange().first <= BBAddress &&
4300                "Bad output address for basic block.");
4301         assert((PrevBB->getOutputAddressRange().first != BBAddress ||
4302                 !hasInstructions() || !PrevBB->getNumNonPseudos()) &&
4303                "Bad output address for basic block.");
4304         PrevBB->setOutputEndAddress(BBAddress);
4305       }
4306       PrevBB = BB;
4307     }
4308 
4309     PrevBB->setOutputEndAddress(PrevBB->isSplit()
4310                                     ? FF.getAddress() + FF.getImageSize()
4311                                     : getOutputAddress() + getOutputSize());
4312   }
4313 
4314   // Reset output addresses for deleted blocks.
4315   for (BinaryBasicBlock *BB : DeletedBasicBlocks) {
4316     BB->setOutputStartAddress(0);
4317     BB->setOutputEndAddress(0);
4318   }
4319 }
4320 
4321 DebugAddressRangesVector BinaryFunction::getOutputAddressRanges() const {
4322   DebugAddressRangesVector OutputRanges;
4323 
4324   if (isFolded())
4325     return OutputRanges;
4326 
4327   if (IsFragment)
4328     return OutputRanges;
4329 
4330   OutputRanges.emplace_back(getOutputAddress(),
4331                             getOutputAddress() + getOutputSize());
4332   if (isSplit()) {
4333     assert(isEmitted() && "split function should be emitted");
4334     for (const FunctionFragment &FF : getLayout().getSplitFragments())
4335       OutputRanges.emplace_back(FF.getAddress(),
4336                                 FF.getAddress() + FF.getImageSize());
4337   }
4338 
4339   if (isSimple())
4340     return OutputRanges;
4341 
4342   for (BinaryFunction *Frag : Fragments) {
4343     assert(!Frag->isSimple() &&
4344            "fragment of non-simple function should also be non-simple");
4345     OutputRanges.emplace_back(Frag->getOutputAddress(),
4346                               Frag->getOutputAddress() + Frag->getOutputSize());
4347   }
4348 
4349   return OutputRanges;
4350 }
4351 
4352 uint64_t BinaryFunction::translateInputToOutputAddress(uint64_t Address) const {
4353   if (isFolded())
4354     return 0;
4355 
4356   // If the function hasn't changed return the same address.
4357   if (!isEmitted())
4358     return Address;
4359 
4360   if (Address < getAddress())
4361     return 0;
4362 
4363   // Check if the address is associated with an instruction that is tracked
4364   // by address translation.
4365   if (auto OutputAddress = BC.getIOAddressMap().lookup(Address))
4366     return *OutputAddress;
4367 
4368   // FIXME: #18950828 - we rely on relative offsets inside basic blocks to stay
4369   //        intact. Instead we can use pseudo instructions and/or annotations.
4370   const uint64_t Offset = Address - getAddress();
4371   const BinaryBasicBlock *BB = getBasicBlockContainingOffset(Offset);
4372   if (!BB) {
4373     // Special case for address immediately past the end of the function.
4374     if (Offset == getSize())
4375       return getOutputAddress() + getOutputSize();
4376 
4377     return 0;
4378   }
4379 
4380   return std::min(BB->getOutputAddressRange().first + Offset - BB->getOffset(),
4381                   BB->getOutputAddressRange().second);
4382 }
4383 
4384 DebugAddressRangesVector
4385 BinaryFunction::translateInputToOutputRange(DebugAddressRange InRange) const {
4386   DebugAddressRangesVector OutRanges;
4387 
4388   // The function was removed from the output. Return an empty range.
4389   if (isFolded())
4390     return OutRanges;
4391 
4392   // If the function hasn't changed return the same range.
4393   if (!isEmitted()) {
4394     OutRanges.emplace_back(InRange);
4395     return OutRanges;
4396   }
4397 
4398   if (!containsAddress(InRange.LowPC))
4399     return OutRanges;
4400 
4401   // Special case of an empty range [X, X). Some tools expect X to be updated.
4402   if (InRange.LowPC == InRange.HighPC) {
4403     if (uint64_t NewPC = translateInputToOutputAddress(InRange.LowPC))
4404       OutRanges.push_back(DebugAddressRange{NewPC, NewPC});
4405     return OutRanges;
4406   }
4407 
4408   uint64_t InputOffset = InRange.LowPC - getAddress();
4409   const uint64_t InputEndOffset =
4410       std::min(InRange.HighPC - getAddress(), getSize());
4411 
4412   auto BBI = llvm::upper_bound(BasicBlockOffsets,
4413                                BasicBlockOffset(InputOffset, nullptr),
4414                                CompareBasicBlockOffsets());
4415   assert(BBI != BasicBlockOffsets.begin());
4416 
4417   // Iterate over blocks in the input order using BasicBlockOffsets.
4418   for (--BBI; InputOffset < InputEndOffset && BBI != BasicBlockOffsets.end();
4419        InputOffset = BBI->second->getEndOffset(), ++BBI) {
4420     const BinaryBasicBlock &BB = *BBI->second;
4421     if (InputOffset < BB.getOffset() || InputOffset >= BB.getEndOffset()) {
4422       LLVM_DEBUG(
4423           dbgs() << "BOLT-DEBUG: invalid debug address range detected for "
4424                  << *this << " : [0x" << Twine::utohexstr(InRange.LowPC)
4425                  << ", 0x" << Twine::utohexstr(InRange.HighPC) << "]\n");
4426       break;
4427     }
4428 
4429     // Skip the block if it wasn't emitted.
4430     if (!BB.getOutputAddressRange().first)
4431       continue;
4432 
4433     // Find output address for an instruction with an offset greater or equal
4434     // to /p Offset. The output address should fall within the same basic
4435     // block boundaries.
4436     auto translateBlockOffset = [&](const uint64_t Offset) {
4437       const uint64_t OutAddress = BB.getOutputAddressRange().first + Offset;
4438       return std::min(OutAddress, BB.getOutputAddressRange().second);
4439     };
4440 
4441     uint64_t OutLowPC = BB.getOutputAddressRange().first;
4442     if (InputOffset > BB.getOffset())
4443       OutLowPC = translateBlockOffset(InputOffset - BB.getOffset());
4444 
4445     uint64_t OutHighPC = BB.getOutputAddressRange().second;
4446     if (InputEndOffset < BB.getEndOffset()) {
4447       assert(InputEndOffset >= BB.getOffset());
4448       OutHighPC = translateBlockOffset(InputEndOffset - BB.getOffset());
4449     }
4450 
4451     // Check if we can expand the last translated range.
4452     if (!OutRanges.empty() && OutRanges.back().HighPC == OutLowPC)
4453       OutRanges.back().HighPC = std::max(OutRanges.back().HighPC, OutHighPC);
4454     else
4455       OutRanges.emplace_back(OutLowPC, std::max(OutLowPC, OutHighPC));
4456   }
4457 
4458   LLVM_DEBUG({
4459     dbgs() << "BOLT-DEBUG: translated address range " << InRange << " -> ";
4460     for (const DebugAddressRange &R : OutRanges)
4461       dbgs() << R << ' ';
4462     dbgs() << '\n';
4463   });
4464 
4465   return OutRanges;
4466 }
4467 
4468 MCInst *BinaryFunction::getInstructionAtOffset(uint64_t Offset) {
4469   if (CurrentState == State::Disassembled) {
4470     auto II = Instructions.find(Offset);
4471     return (II == Instructions.end()) ? nullptr : &II->second;
4472   } else if (CurrentState == State::CFG) {
4473     BinaryBasicBlock *BB = getBasicBlockContainingOffset(Offset);
4474     if (!BB)
4475       return nullptr;
4476 
4477     for (MCInst &Inst : *BB) {
4478       constexpr uint32_t InvalidOffset = std::numeric_limits<uint32_t>::max();
4479       if (Offset == BC.MIB->getOffsetWithDefault(Inst, InvalidOffset))
4480         return &Inst;
4481     }
4482 
4483     if (MCInst *LastInstr = BB->getLastNonPseudoInstr()) {
4484       if (std::optional<uint32_t> Size = BC.MIB->getSize(*LastInstr)) {
4485         if (BB->getEndOffset() - Offset == Size) {
4486           return LastInstr;
4487         }
4488       }
4489     }
4490 
4491     return nullptr;
4492   } else {
4493     llvm_unreachable("invalid CFG state to use getInstructionAtOffset()");
4494   }
4495 }
4496 
4497 MCInst *BinaryFunction::getInstructionContainingOffset(uint64_t Offset) {
4498   assert(CurrentState == State::Disassembled && "Wrong function state");
4499 
4500   if (Offset > Size)
4501     return nullptr;
4502 
4503   auto II = Instructions.upper_bound(Offset);
4504   assert(II != Instructions.begin() && "First instruction not at offset 0");
4505   --II;
4506   return &II->second;
4507 }
4508 
4509 void BinaryFunction::printLoopInfo(raw_ostream &OS) const {
4510   if (!opts::shouldPrint(*this))
4511     return;
4512 
4513   OS << "Loop Info for Function \"" << *this << "\"";
4514   if (hasValidProfile())
4515     OS << " (count: " << getExecutionCount() << ")";
4516   OS << "\n";
4517 
4518   std::stack<BinaryLoop *> St;
4519   for (BinaryLoop *L : *BLI)
4520     St.push(L);
4521   while (!St.empty()) {
4522     BinaryLoop *L = St.top();
4523     St.pop();
4524 
4525     for (BinaryLoop *Inner : *L)
4526       St.push(Inner);
4527 
4528     if (!hasValidProfile())
4529       continue;
4530 
4531     OS << (L->getLoopDepth() > 1 ? "Nested" : "Outer")
4532        << " loop header: " << L->getHeader()->getName();
4533     OS << "\n";
4534     OS << "Loop basic blocks: ";
4535     ListSeparator LS;
4536     for (BinaryBasicBlock *BB : L->blocks())
4537       OS << LS << BB->getName();
4538     OS << "\n";
4539     if (hasValidProfile()) {
4540       OS << "Total back edge count: " << L->TotalBackEdgeCount << "\n";
4541       OS << "Loop entry count: " << L->EntryCount << "\n";
4542       OS << "Loop exit count: " << L->ExitCount << "\n";
4543       if (L->EntryCount > 0) {
4544         OS << "Average iters per entry: "
4545            << format("%.4lf", (double)L->TotalBackEdgeCount / L->EntryCount)
4546            << "\n";
4547       }
4548     }
4549     OS << "----\n";
4550   }
4551 
4552   OS << "Total number of loops: " << BLI->TotalLoops << "\n";
4553   OS << "Number of outer loops: " << BLI->OuterLoops << "\n";
4554   OS << "Maximum nested loop depth: " << BLI->MaximumDepth << "\n\n";
4555 }
4556 
4557 bool BinaryFunction::isAArch64Veneer() const {
4558   if (empty() || hasIslandsInfo())
4559     return false;
4560 
4561   BinaryBasicBlock &BB = **BasicBlocks.begin();
4562   for (MCInst &Inst : BB)
4563     if (!BC.MIB->hasAnnotation(Inst, "AArch64Veneer"))
4564       return false;
4565 
4566   for (auto I = BasicBlocks.begin() + 1, E = BasicBlocks.end(); I != E; ++I) {
4567     for (MCInst &Inst : **I)
4568       if (!BC.MIB->isNoop(Inst))
4569         return false;
4570   }
4571 
4572   return true;
4573 }
4574 
4575 void BinaryFunction::addRelocation(uint64_t Address, MCSymbol *Symbol,
4576                                    uint64_t RelType, uint64_t Addend,
4577                                    uint64_t Value) {
4578   assert(Address >= getAddress() && Address < getAddress() + getMaxSize() &&
4579          "address is outside of the function");
4580   uint64_t Offset = Address - getAddress();
4581   LLVM_DEBUG(dbgs() << "BOLT-DEBUG: addRelocation in "
4582                     << formatv("{0}@{1:x} against {2}\n", *this, Offset,
4583                                (Symbol ? Symbol->getName() : "<undef>")));
4584   bool IsCI = BC.isAArch64() && isInConstantIsland(Address);
4585   std::map<uint64_t, Relocation> &Rels =
4586       IsCI ? Islands->Relocations : Relocations;
4587   if (BC.MIB->shouldRecordCodeRelocation(RelType))
4588     Rels[Offset] = Relocation{Offset, Symbol, RelType, Addend, Value};
4589 }
4590 
4591 } // namespace bolt
4592 } // namespace llvm
4593