src/llvm/lib/CodeGen/MachineModuleInfo.cpp

   1 //===-- llvm/CodeGen/MachineModuleInfo.cpp ----------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/CodeGen/MachineModuleInfo.h"
  11 #include "llvm/ADT/PointerUnion.h"
  12 #include "llvm/Analysis/ValueTracking.h"
  13 #include "llvm/CodeGen/MachineFunction.h"
  14 #include "llvm/CodeGen/MachineFunctionPass.h"
  15 #include "llvm/CodeGen/Passes.h"
  16 #include "llvm/IR/Constants.h"
  17 #include "llvm/IR/DerivedTypes.h"
  18 #include "llvm/IR/GlobalVariable.h"
  19 #include "llvm/IR/Module.h"
  20 #include "llvm/MC/MCObjectFileInfo.h"
  21 #include "llvm/MC/MCSymbol.h"
  22 #include "llvm/Support/Dwarf.h"
  23 #include "llvm/Support/ErrorHandling.h"
  24 using namespace llvm;
  25 using namespace llvm::dwarf;
  26
  27 // Handle the Pass registration stuff necessary to use DataLayout's.
  28 INITIALIZE_PASS(MachineModuleInfo, "machinemoduleinfo",
  29                 "Machine Module Information", false, false)
  30 char MachineModuleInfo::ID = 0;
  31
  32 // Out of line virtual method.
  33 MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
  34
  35 namespace llvm {
  36 class MMIAddrLabelMapCallbackPtr : CallbackVH {
  37   MMIAddrLabelMap *Map;
  38 public:
  39   MMIAddrLabelMapCallbackPtr() : Map(nullptr) {}
  40   MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V), Map(nullptr) {}
  41
  42   void setPtr(BasicBlock *BB) {
  43     ValueHandleBase::operator=(BB);
  44   }
  45
  46   void setMap(MMIAddrLabelMap *map) { Map = map; }
  47
  48   void deleted() override;
  49   void allUsesReplacedWith(Value *V2) override;
  50 };
  51
  52 class MMIAddrLabelMap {
  53   MCContext &Context;
  54   struct AddrLabelSymEntry {
  55     /// Symbols - The symbols for the label.  This is a pointer union that is
  56     /// either one symbol (the common case) or a list of symbols.
  57     PointerUnion<MCSymbol *, std::vector<MCSymbol*>*> Symbols;
  58
  59     Function *Fn;   // The containing function of the BasicBlock.
  60     unsigned Index; // The index in BBCallbacks for the BasicBlock.
  61   };
  62
  63   DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
  64
  65   /// BBCallbacks - Callbacks for the BasicBlock's that we have entries for.  We
  66   /// use this so we get notified if a block is deleted or RAUWd.
  67   std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
  68
  69   /// DeletedAddrLabelsNeedingEmission - This is a per-function list of symbols
  70   /// whose corresponding BasicBlock got deleted.  These symbols need to be
  71   /// emitted at some point in the file, so AsmPrinter emits them after the
  72   /// function body.
  73   DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >
  74     DeletedAddrLabelsNeedingEmission;
  75 public:
  76
  77   MMIAddrLabelMap(MCContext &context) : Context(context) {}
  78   ~MMIAddrLabelMap() {
  79     assert(DeletedAddrLabelsNeedingEmission.empty() &&
  80            "Some labels for deleted blocks never got emitted");
  81
  82     // Deallocate any of the 'list of symbols' case.
  83     for (DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry>::iterator
  84          I = AddrLabelSymbols.begin(), E = AddrLabelSymbols.end(); I != E; ++I)
  85       if (I->second.Symbols.is<std::vector<MCSymbol*>*>())
  86         delete I->second.Symbols.get<std::vector<MCSymbol*>*>();
  87   }
  88
  89   MCSymbol *getAddrLabelSymbol(BasicBlock *BB);
  90   std::vector<MCSymbol*> getAddrLabelSymbolToEmit(BasicBlock *BB);
  91
  92   void takeDeletedSymbolsForFunction(Function *F,
  93                                      std::vector<MCSymbol*> &Result);
  94
  95   void UpdateForDeletedBlock(BasicBlock *BB);
  96   void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
  97 };
  98 }
  99
 100 MCSymbol *MMIAddrLabelMap::getAddrLabelSymbol(BasicBlock *BB) {
 101   assert(BB->hasAddressTaken() &&
 102          "Shouldn't get label for block without address taken");
 103   AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
 104
 105   // If we already had an entry for this block, just return it.
 106   if (!Entry.Symbols.isNull()) {
 107     assert(BB->getParent() == Entry.Fn && "Parent changed");
 108     if (Entry.Symbols.is<MCSymbol*>())
 109       return Entry.Symbols.get<MCSymbol*>();
 110     return (*Entry.Symbols.get<std::vector<MCSymbol*>*>())[0];
 111   }
 112
 113   // Otherwise, this is a new entry, create a new symbol for it and add an
 114   // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
 115   BBCallbacks.push_back(BB);
 116   BBCallbacks.back().setMap(this);
 117   Entry.Index = BBCallbacks.size()-1;
 118   Entry.Fn = BB->getParent();
 119   MCSymbol *Result = Context.CreateTempSymbol();
 120   Entry.Symbols = Result;
 121   return Result;
 122 }
 123
 124 std::vector<MCSymbol*>
 125 MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
 126   assert(BB->hasAddressTaken() &&
 127          "Shouldn't get label for block without address taken");
 128   AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
 129
 130   std::vector<MCSymbol*> Result;
 131
 132   // If we already had an entry for this block, just return it.
 133   if (Entry.Symbols.isNull())
 134     Result.push_back(getAddrLabelSymbol(BB));
 135   else if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>())
 136     Result.push_back(Sym);
 137   else
 138     Result = *Entry.Symbols.get<std::vector<MCSymbol*>*>();
 139   return Result;
 140 }
 141
 142
 143 /// takeDeletedSymbolsForFunction - If we have any deleted symbols for F, return
 144 /// them.
 145 void MMIAddrLabelMap::
 146 takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {
 147   DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >::iterator I =
 148     DeletedAddrLabelsNeedingEmission.find(F);
 149
 150   // If there are no entries for the function, just return.
 151   if (I == DeletedAddrLabelsNeedingEmission.end()) return;
 152
 153   // Otherwise, take the list.
 154   std::swap(Result, I->second);
 155   DeletedAddrLabelsNeedingEmission.erase(I);
 156 }
 157
 158
 159 void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
 160   // If the block got deleted, there is no need for the symbol.  If the symbol
 161   // was already emitted, we can just forget about it, otherwise we need to
 162   // queue it up for later emission when the function is output.
 163   AddrLabelSymEntry Entry = AddrLabelSymbols[BB];
 164   AddrLabelSymbols.erase(BB);
 165   assert(!Entry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
 166   BBCallbacks[Entry.Index] = nullptr;  // Clear the callback.
 167
 168   assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&
 169          "Block/parent mismatch");
 170
 171   // Handle both the single and the multiple symbols cases.
 172   if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>()) {
 173     if (Sym->isDefined())
 174       return;
 175
 176     // If the block is not yet defined, we need to emit it at the end of the
 177     // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
 178     // for the containing Function.  Since the block is being deleted, its
 179     // parent may already be removed, we have to get the function from 'Entry'.
 180     DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
 181   } else {
 182     std::vector<MCSymbol*> *Syms = Entry.Symbols.get<std::vector<MCSymbol*>*>();
 183
 184     for (unsigned i = 0, e = Syms->size(); i != e; ++i) {
 185       MCSymbol *Sym = (*Syms)[i];
 186       if (Sym->isDefined()) continue;  // Ignore already emitted labels.
 187
 188       // If the block is not yet defined, we need to emit it at the end of the
 189       // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
 190       // for the containing Function.  Since the block is being deleted, its
 191       // parent may already be removed, we have to get the function from
 192       // 'Entry'.
 193       DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
 194     }
 195
 196     // The entry is deleted, free the memory associated with the symbol list.
 197     delete Syms;
 198   }
 199 }
 200
 201 void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
 202   // Get the entry for the RAUW'd block and remove it from our map.
 203   AddrLabelSymEntry OldEntry = AddrLabelSymbols[Old];
 204   AddrLabelSymbols.erase(Old);
 205   assert(!OldEntry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
 206
 207   AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
 208
 209   // If New is not address taken, just move our symbol over to it.
 210   if (NewEntry.Symbols.isNull()) {
 211     BBCallbacks[OldEntry.Index].setPtr(New);    // Update the callback.
 212     NewEntry = OldEntry;     // Set New's entry.
 213     return;
 214   }
 215
 216   BBCallbacks[OldEntry.Index] = nullptr;    // Update the callback.
 217
 218   // Otherwise, we need to add the old symbol to the new block's set.  If it is
 219   // just a single entry, upgrade it to a symbol list.
 220   if (MCSymbol *PrevSym = NewEntry.Symbols.dyn_cast<MCSymbol*>()) {
 221     std::vector<MCSymbol*> *SymList = new std::vector<MCSymbol*>();
 222     SymList->push_back(PrevSym);
 223     NewEntry.Symbols = SymList;
 224   }
 225
 226   std::vector<MCSymbol*> *SymList =
 227     NewEntry.Symbols.get<std::vector<MCSymbol*>*>();
 228
 229   // If the old entry was a single symbol, add it.
 230   if (MCSymbol *Sym = OldEntry.Symbols.dyn_cast<MCSymbol*>()) {
 231     SymList->push_back(Sym);
 232     return;
 233   }
 234
 235   // Otherwise, concatenate the list.
 236   std::vector<MCSymbol*> *Syms =OldEntry.Symbols.get<std::vector<MCSymbol*>*>();
 237   SymList->insert(SymList->end(), Syms->begin(), Syms->end());
 238   delete Syms;
 239 }
 240
 241
 242 void MMIAddrLabelMapCallbackPtr::deleted() {
 243   Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
 244 }
 245
 246 void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
 247   Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
 248 }
 249
 250
 251 //===----------------------------------------------------------------------===//
 252
 253 MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI,
 254                                      const MCRegisterInfo &MRI,
 255                                      const MCObjectFileInfo *MOFI)
 256   : ImmutablePass(ID), Context(&MAI, &MRI, MOFI, nullptr, false) {
 257   initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
 258 }
 259
 260 MachineModuleInfo::MachineModuleInfo()
 261   : ImmutablePass(ID), Context(nullptr, nullptr, nullptr) {
 262   llvm_unreachable("This MachineModuleInfo constructor should never be called, "
 263                    "MMI should always be explicitly constructed by "
 264                    "LLVMTargetMachine");
 265 }
 266
 267 MachineModuleInfo::~MachineModuleInfo() {
 268 }
 269
 270 bool MachineModuleInfo::doInitialization(Module &M) {
 271
 272   ObjFileMMI = nullptr;
 273   CurCallSite = 0;
 274   CallsEHReturn = 0;
 275   CallsUnwindInit = 0;
 276   DbgInfoAvailable = UsesVAFloatArgument = UsesMorestackAddr = false;
 277   // Always emit some info, by default "no personality" info.
 278   Personalities.push_back(nullptr);
 279   AddrLabelSymbols = nullptr;
 280   TheModule = nullptr;
 281
 282   return false;
 283 }
 284
 285 bool MachineModuleInfo::doFinalization(Module &M) {
 286
 287   Personalities.clear();
 288
 289   delete AddrLabelSymbols;
 290   AddrLabelSymbols = nullptr;
 291
 292   Context.reset();
 293
 294   delete ObjFileMMI;
 295   ObjFileMMI = nullptr;
 296
 297   return false;
 298 }
 299
 300 /// EndFunction - Discard function meta information.
 301 ///
 302 void MachineModuleInfo::EndFunction() {
 303   // Clean up frame info.
 304   FrameInstructions.clear();
 305
 306   // Clean up exception info.
 307   LandingPads.clear();
 308   CallSiteMap.clear();
 309   TypeInfos.clear();
 310   FilterIds.clear();
 311   FilterEnds.clear();
 312   CallsEHReturn = 0;
 313   CallsUnwindInit = 0;
 314   VariableDbgInfos.clear();
 315 }
 316
 317 /// AnalyzeModule - Scan the module for global debug information.
 318 ///
 319 void MachineModuleInfo::AnalyzeModule(const Module &M) {
 320   // Insert functions in the llvm.used array (but not llvm.compiler.used) into
 321   // UsedFunctions.
 322   const GlobalVariable *GV = M.getGlobalVariable("llvm.used");
 323   if (!GV || !GV->hasInitializer()) return;
 324
 325   // Should be an array of 'i8*'.
 326   const ConstantArray *InitList = cast<ConstantArray>(GV->getInitializer());
 327
 328   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
 329     if (const Function *F =
 330           dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
 331       UsedFunctions.insert(F);
 332 }
 333
 334 //===- Address of Block Management ----------------------------------------===//
 335
 336
 337 /// getAddrLabelSymbol - Return the symbol to be used for the specified basic
 338 /// block when its address is taken.  This cannot be its normal LBB label
 339 /// because the block may be accessed outside its containing function.
 340 MCSymbol *MachineModuleInfo::getAddrLabelSymbol(const BasicBlock *BB) {
 341   // Lazily create AddrLabelSymbols.
 342   if (!AddrLabelSymbols)
 343     AddrLabelSymbols = new MMIAddrLabelMap(Context);
 344   return AddrLabelSymbols->getAddrLabelSymbol(const_cast<BasicBlock*>(BB));
 345 }
 346
 347 /// getAddrLabelSymbolToEmit - Return the symbol to be used for the specified
 348 /// basic block when its address is taken.  If other blocks were RAUW'd to
 349 /// this one, we may have to emit them as well, return the whole set.
 350 std::vector<MCSymbol*> MachineModuleInfo::
 351 getAddrLabelSymbolToEmit(const BasicBlock *BB) {
 352   // Lazily create AddrLabelSymbols.
 353   if (!AddrLabelSymbols)
 354     AddrLabelSymbols = new MMIAddrLabelMap(Context);
 355  return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));
 356 }
 357
 358
 359 /// takeDeletedSymbolsForFunction - If the specified function has had any
 360 /// references to address-taken blocks generated, but the block got deleted,
 361 /// return the symbol now so we can emit it.  This prevents emitting a
 362 /// reference to a symbol that has no definition.
 363 void MachineModuleInfo::
 364 takeDeletedSymbolsForFunction(const Function *F,
 365                               std::vector<MCSymbol*> &Result) {
 366   // If no blocks have had their addresses taken, we're done.
 367   if (!AddrLabelSymbols) return;
 368   return AddrLabelSymbols->
 369      takeDeletedSymbolsForFunction(const_cast<Function*>(F), Result);
 370 }
 371
 372 //===- EH -----------------------------------------------------------------===//
 373
 374 /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
 375 /// specified MachineBasicBlock.
 376 LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
 377     (MachineBasicBlock *LandingPad) {
 378   unsigned N = LandingPads.size();
 379   for (unsigned i = 0; i < N; ++i) {
 380     LandingPadInfo &LP = LandingPads[i];
 381     if (LP.LandingPadBlock == LandingPad)
 382       return LP;
 383   }
 384
 385   LandingPads.push_back(LandingPadInfo(LandingPad));
 386   return LandingPads[N];
 387 }
 388
 389 /// addInvoke - Provide the begin and end labels of an invoke style call and
 390 /// associate it with a try landing pad block.
 391 void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
 392                                   MCSymbol *BeginLabel, MCSymbol *EndLabel) {
 393   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 394   LP.BeginLabels.push_back(BeginLabel);
 395   LP.EndLabels.push_back(EndLabel);
 396 }
 397
 398 /// addLandingPad - Provide the label of a try LandingPad block.
 399 ///
 400 MCSymbol *MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
 401   MCSymbol *LandingPadLabel = Context.CreateTempSymbol();
 402   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 403   LP.LandingPadLabel = LandingPadLabel;
 404   return LandingPadLabel;
 405 }
 406
 407 /// addPersonality - Provide the personality function for the exception
 408 /// information.
 409 void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
 410                                        const Function *Personality) {
 411   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 412   LP.Personality = Personality;
 413
 414   for (unsigned i = 0; i < Personalities.size(); ++i)
 415     if (Personalities[i] == Personality)
 416       return;
 417
 418   // If this is the first personality we're adding go
 419   // ahead and add it at the beginning.
 420   if (!Personalities[0])
 421     Personalities[0] = Personality;
 422   else
 423     Personalities.push_back(Personality);
 424 }
 425
 426 /// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
 427 ///
 428 void MachineModuleInfo::
 429 addCatchTypeInfo(MachineBasicBlock *LandingPad,
 430                  ArrayRef<const GlobalValue *> TyInfo) {
 431   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 432   for (unsigned N = TyInfo.size(); N; --N)
 433     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
 434 }
 435
 436 /// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
 437 ///
 438 void MachineModuleInfo::
 439 addFilterTypeInfo(MachineBasicBlock *LandingPad,
 440                   ArrayRef<const GlobalValue *> TyInfo) {
 441   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 442   std::vector<unsigned> IdsInFilter(TyInfo.size());
 443   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 444     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 445   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 446 }
 447
 448 /// addCleanup - Add a cleanup action for a landing pad.
 449 ///
 450 void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
 451   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 452   LP.TypeIds.push_back(0);
 453 }
 454
 455 /// TidyLandingPads - Remap landing pad labels and remove any deleted landing
 456 /// pads.
 457 void MachineModuleInfo::TidyLandingPads(DenseMap<MCSymbol*, uintptr_t> *LPMap) {
 458   for (unsigned i = 0; i != LandingPads.size(); ) {
 459     LandingPadInfo &LandingPad = LandingPads[i];
 460     if (LandingPad.LandingPadLabel &&
 461         !LandingPad.LandingPadLabel->isDefined() &&
 462         (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
 463       LandingPad.LandingPadLabel = nullptr;
 464
 465     // Special case: we *should* emit LPs with null LP MBB. This indicates
 466     // "nounwind" case.
 467     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 468       LandingPads.erase(LandingPads.begin() + i);
 469       continue;
 470     }
 471
 472     for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
 473       MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
 474       MCSymbol *EndLabel = LandingPad.EndLabels[j];
 475       if ((BeginLabel->isDefined() ||
 476            (LPMap && (*LPMap)[BeginLabel] != 0)) &&
 477           (EndLabel->isDefined() ||
 478            (LPMap && (*LPMap)[EndLabel] != 0))) continue;
 479
 480       LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 481       LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 482       --j, --e;
 483     }
 484
 485     // Remove landing pads with no try-ranges.
 486     if (LandingPads[i].BeginLabels.empty()) {
 487       LandingPads.erase(LandingPads.begin() + i);
 488       continue;
 489     }
 490
 491     // If there is no landing pad, ensure that the list of typeids is empty.
 492     // If the only typeid is a cleanup, this is the same as having no typeids.
 493     if (!LandingPad.LandingPadBlock ||
 494         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 495       LandingPad.TypeIds.clear();
 496     ++i;
 497   }
 498 }
 499
 500 /// setCallSiteLandingPad - Map the landing pad's EH symbol to the call site
 501 /// indexes.
 502 void MachineModuleInfo::setCallSiteLandingPad(MCSymbol *Sym,
 503                                               ArrayRef<unsigned> Sites) {
 504   LPadToCallSiteMap[Sym].append(Sites.begin(), Sites.end());
 505 }
 506
 507 /// getTypeIDFor - Return the type id for the specified typeinfo.  This is
 508 /// function wide.
 509 unsigned MachineModuleInfo::getTypeIDFor(const GlobalValue *TI) {
 510   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
 511     if (TypeInfos[i] == TI) return i + 1;
 512
 513   TypeInfos.push_back(TI);
 514   return TypeInfos.size();
 515 }
 516
 517 /// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
 518 /// function wide.
 519 int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
 520   // If the new filter coincides with the tail of an existing filter, then
 521   // re-use the existing filter.  Folding filters more than this requires
 522   // re-ordering filters and/or their elements - probably not worth it.
 523   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
 524        E = FilterEnds.end(); I != E; ++I) {
 525     unsigned i = *I, j = TyIds.size();
 526
 527     while (i && j)
 528       if (FilterIds[--i] != TyIds[--j])
 529         goto try_next;
 530
 531     if (!j)
 532       // The new filter coincides with range [i, end) of the existing filter.
 533       return -(1 + i);
 534
 535 try_next:;
 536   }
 537
 538   // Add the new filter.
 539   int FilterID = -(1 + FilterIds.size());
 540   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
 541   FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
 542   FilterEnds.push_back(FilterIds.size());
 543   FilterIds.push_back(0); // terminator
 544   return FilterID;
 545 }
 546
 547 /// getPersonality - Return the personality function for the current function.
 548 const Function *MachineModuleInfo::getPersonality() const {
 549   // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
 550   // function
 551   return !LandingPads.empty() ? LandingPads[0].Personality : nullptr;
 552 }
 553
 554 /// getPersonalityIndex - Return unique index for current personality
 555 /// function. NULL/first personality function should always get zero index.
 556 unsigned MachineModuleInfo::getPersonalityIndex() const {
 557   const Function* Personality = nullptr;
 558
 559   // Scan landing pads. If there is at least one non-NULL personality - use it.
 560   for (unsigned i = 0, e = LandingPads.size(); i != e; ++i)
 561     if (LandingPads[i].Personality) {
 562       Personality = LandingPads[i].Personality;
 563       break;
 564     }
 565
 566   for (unsigned i = 0, e = Personalities.size(); i < e; ++i) {
 567     if (Personalities[i] == Personality)
 568       return i;
 569   }
 570
 571   // This will happen if the current personality function is
 572   // in the zero index.
 573   return 0;
 574 }