lib/IR/LegacyPassManager.cpp

   1 //===- LegacyPassManager.cpp - LLVM Pass Infrastructure Implementation ----===//
   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 // This file implements the legacy LLVM Pass Manager infrastructure.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/IR/LegacyPassManager.h"
  15 #include "llvm/IR/IRPrintingPasses.h"
  16 #include "llvm/IR/LLVMContext.h"
  17 #include "llvm/IR/LegacyPassManagers.h"
  18 #include "llvm/IR/LegacyPassNameParser.h"
  19 #include "llvm/IR/Module.h"
  20 #include "llvm/Support/Chrono.h"
  21 #include "llvm/Support/CommandLine.h"
  22 #include "llvm/Support/Debug.h"
  23 #include "llvm/Support/Error.h"
  24 #include "llvm/Support/ErrorHandling.h"
  25 #include "llvm/Support/ManagedStatic.h"
  26 #include "llvm/Support/Mutex.h"
  27 #include "llvm/Support/Timer.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include <algorithm>
  30 #include <map>
  31 #include <unordered_set>
  32 using namespace llvm;
  33 using namespace llvm::legacy;
  34
  35 // See PassManagers.h for Pass Manager infrastructure overview.
  36
  37 //===----------------------------------------------------------------------===//
  38 // Pass debugging information.  Often it is useful to find out what pass is
  39 // running when a crash occurs in a utility.  When this library is compiled with
  40 // debugging on, a command line option (--debug-pass) is enabled that causes the
  41 // pass name to be printed before it executes.
  42 //
  43
  44 namespace {
  45 // Different debug levels that can be enabled...
  46 enum PassDebugLevel {
  47   Disabled, Arguments, Structure, Executions, Details
  48 };
  49 }
  50
  51 static cl::opt<enum PassDebugLevel>
  52 PassDebugging("debug-pass", cl::Hidden,
  53                   cl::desc("Print PassManager debugging information"),
  54                   cl::values(
  55   clEnumVal(Disabled  , "disable debug output"),
  56   clEnumVal(Arguments , "print pass arguments to pass to 'opt'"),
  57   clEnumVal(Structure , "print pass structure before run()"),
  58   clEnumVal(Executions, "print pass name before it is executed"),
  59   clEnumVal(Details   , "print pass details when it is executed")));
  60
  61 namespace {
  62 typedef llvm::cl::list<const llvm::PassInfo *, bool, PassNameParser>
  63 PassOptionList;
  64 }
  65
  66 // Print IR out before/after specified passes.
  67 static PassOptionList
  68 PrintBefore("print-before",
  69             llvm::cl::desc("Print IR before specified passes"),
  70             cl::Hidden);
  71
  72 static PassOptionList
  73 PrintAfter("print-after",
  74            llvm::cl::desc("Print IR after specified passes"),
  75            cl::Hidden);
  76
  77 static cl::opt<bool>
  78 PrintBeforeAll("print-before-all",
  79                llvm::cl::desc("Print IR before each pass"),
  80                cl::init(false));
  81 static cl::opt<bool>
  82 PrintAfterAll("print-after-all",
  83               llvm::cl::desc("Print IR after each pass"),
  84               cl::init(false));
  85
  86 static cl::list<std::string>
  87     PrintFuncsList("filter-print-funcs", cl::value_desc("function names"),
  88                    cl::desc("Only print IR for functions whose name "
  89                             "match this for all print-[before|after][-all] "
  90                             "options"),
  91                    cl::CommaSeparated);
  92
  93 /// This is a helper to determine whether to print IR before or
  94 /// after a pass.
  95
  96 static bool ShouldPrintBeforeOrAfterPass(const PassInfo *PI,
  97                                          PassOptionList &PassesToPrint) {
  98   for (auto *PassInf : PassesToPrint) {
  99     if (PassInf)
 100       if (PassInf->getPassArgument() == PI->getPassArgument()) {
 101         return true;
 102       }
 103   }
 104   return false;
 105 }
 106
 107 /// This is a utility to check whether a pass should have IR dumped
 108 /// before it.
 109 static bool ShouldPrintBeforePass(const PassInfo *PI) {
 110   return PrintBeforeAll || ShouldPrintBeforeOrAfterPass(PI, PrintBefore);
 111 }
 112
 113 /// This is a utility to check whether a pass should have IR dumped
 114 /// after it.
 115 static bool ShouldPrintAfterPass(const PassInfo *PI) {
 116   return PrintAfterAll || ShouldPrintBeforeOrAfterPass(PI, PrintAfter);
 117 }
 118
 119 bool llvm::isFunctionInPrintList(StringRef FunctionName) {
 120   static std::unordered_set<std::string> PrintFuncNames(PrintFuncsList.begin(),
 121                                                         PrintFuncsList.end());
 122   return PrintFuncNames.empty() || PrintFuncNames.count(FunctionName);
 123 }
 124 /// isPassDebuggingExecutionsOrMore - Return true if -debug-pass=Executions
 125 /// or higher is specified.
 126 bool PMDataManager::isPassDebuggingExecutionsOrMore() const {
 127   return PassDebugging >= Executions;
 128 }
 129
 130
 131
 132
 133 void PassManagerPrettyStackEntry::print(raw_ostream &OS) const {
 134   if (!V && !M)
 135     OS << "Releasing pass '";
 136   else
 137     OS << "Running pass '";
 138
 139   OS << P->getPassName() << "'";
 140
 141   if (M) {
 142     OS << " on module '" << M->getModuleIdentifier() << "'.\n";
 143     return;
 144   }
 145   if (!V) {
 146     OS << '\n';
 147     return;
 148   }
 149
 150   OS << " on ";
 151   if (isa<Function>(V))
 152     OS << "function";
 153   else if (isa<BasicBlock>(V))
 154     OS << "basic block";
 155   else
 156     OS << "value";
 157
 158   OS << " '";
 159   V->printAsOperand(OS, /*PrintTy=*/false, M);
 160   OS << "'\n";
 161 }
 162
 163
 164 namespace {
 165 //===----------------------------------------------------------------------===//
 166 // BBPassManager
 167 //
 168 /// BBPassManager manages BasicBlockPass. It batches all the
 169 /// pass together and sequence them to process one basic block before
 170 /// processing next basic block.
 171 class BBPassManager : public PMDataManager, public FunctionPass {
 172
 173 public:
 174   static char ID;
 175   explicit BBPassManager()
 176     : PMDataManager(), FunctionPass(ID) {}
 177
 178   /// Execute all of the passes scheduled for execution.  Keep track of
 179   /// whether any of the passes modifies the function, and if so, return true.
 180   bool runOnFunction(Function &F) override;
 181
 182   /// Pass Manager itself does not invalidate any analysis info.
 183   void getAnalysisUsage(AnalysisUsage &Info) const override {
 184     Info.setPreservesAll();
 185   }
 186
 187   bool doInitialization(Module &M) override;
 188   bool doInitialization(Function &F);
 189   bool doFinalization(Module &M) override;
 190   bool doFinalization(Function &F);
 191
 192   PMDataManager *getAsPMDataManager() override { return this; }
 193   Pass *getAsPass() override { return this; }
 194
 195   StringRef getPassName() const override { return "BasicBlock Pass Manager"; }
 196
 197   // Print passes managed by this manager
 198   void dumpPassStructure(unsigned Offset) override {
 199     dbgs().indent(Offset*2) << "BasicBlockPass Manager\n";
 200     for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
 201       BasicBlockPass *BP = getContainedPass(Index);
 202       BP->dumpPassStructure(Offset + 1);
 203       dumpLastUses(BP, Offset+1);
 204     }
 205   }
 206
 207   BasicBlockPass *getContainedPass(unsigned N) {
 208     assert(N < PassVector.size() && "Pass number out of range!");
 209     BasicBlockPass *BP = static_cast<BasicBlockPass *>(PassVector[N]);
 210     return BP;
 211   }
 212
 213   PassManagerType getPassManagerType() const override {
 214     return PMT_BasicBlockPassManager;
 215   }
 216 };
 217
 218 char BBPassManager::ID = 0;
 219 } // End anonymous namespace
 220
 221 namespace llvm {
 222 namespace legacy {
 223 //===----------------------------------------------------------------------===//
 224 // FunctionPassManagerImpl
 225 //
 226 /// FunctionPassManagerImpl manages FPPassManagers
 227 class FunctionPassManagerImpl : public Pass,
 228                                 public PMDataManager,
 229                                 public PMTopLevelManager {
 230   virtual void anchor();
 231 private:
 232   bool wasRun;
 233 public:
 234   static char ID;
 235   explicit FunctionPassManagerImpl() :
 236     Pass(PT_PassManager, ID), PMDataManager(),
 237     PMTopLevelManager(new FPPassManager()), wasRun(false) {}
 238
 239   /// \copydoc FunctionPassManager::add()
 240   void add(Pass *P) {
 241     schedulePass(P);
 242   }
 243
 244   /// createPrinterPass - Get a function printer pass.
 245   Pass *createPrinterPass(raw_ostream &O,
 246                           const std::string &Banner) const override {
 247     return createPrintFunctionPass(O, Banner);
 248   }
 249
 250   // Prepare for running an on the fly pass, freeing memory if needed
 251   // from a previous run.
 252   void releaseMemoryOnTheFly();
 253
 254   /// run - Execute all of the passes scheduled for execution.  Keep track of
 255   /// whether any of the passes modifies the module, and if so, return true.
 256   bool run(Function &F);
 257
 258   /// doInitialization - Run all of the initializers for the function passes.
 259   ///
 260   bool doInitialization(Module &M) override;
 261
 262   /// doFinalization - Run all of the finalizers for the function passes.
 263   ///
 264   bool doFinalization(Module &M) override;
 265
 266
 267   PMDataManager *getAsPMDataManager() override { return this; }
 268   Pass *getAsPass() override { return this; }
 269   PassManagerType getTopLevelPassManagerType() override {
 270     return PMT_FunctionPassManager;
 271   }
 272
 273   /// Pass Manager itself does not invalidate any analysis info.
 274   void getAnalysisUsage(AnalysisUsage &Info) const override {
 275     Info.setPreservesAll();
 276   }
 277
 278   FPPassManager *getContainedManager(unsigned N) {
 279     assert(N < PassManagers.size() && "Pass number out of range!");
 280     FPPassManager *FP = static_cast<FPPassManager *>(PassManagers[N]);
 281     return FP;
 282   }
 283 };
 284
 285 void FunctionPassManagerImpl::anchor() {}
 286
 287 char FunctionPassManagerImpl::ID = 0;
 288 } // End of legacy namespace
 289 } // End of llvm namespace
 290
 291 namespace {
 292 //===----------------------------------------------------------------------===//
 293 // MPPassManager
 294 //
 295 /// MPPassManager manages ModulePasses and function pass managers.
 296 /// It batches all Module passes and function pass managers together and
 297 /// sequences them to process one module.
 298 class MPPassManager : public Pass, public PMDataManager {
 299 public:
 300   static char ID;
 301   explicit MPPassManager() :
 302     Pass(PT_PassManager, ID), PMDataManager() { }
 303
 304   // Delete on the fly managers.
 305   ~MPPassManager() override {
 306     for (auto &OnTheFlyManager : OnTheFlyManagers) {
 307       FunctionPassManagerImpl *FPP = OnTheFlyManager.second;
 308       delete FPP;
 309     }
 310   }
 311
 312   /// createPrinterPass - Get a module printer pass.
 313   Pass *createPrinterPass(raw_ostream &O,
 314                           const std::string &Banner) const override {
 315     return createPrintModulePass(O, Banner);
 316   }
 317
 318   /// run - Execute all of the passes scheduled for execution.  Keep track of
 319   /// whether any of the passes modifies the module, and if so, return true.
 320   bool runOnModule(Module &M);
 321
 322   using llvm::Pass::doInitialization;
 323   using llvm::Pass::doFinalization;
 324
 325   /// Pass Manager itself does not invalidate any analysis info.
 326   void getAnalysisUsage(AnalysisUsage &Info) const override {
 327     Info.setPreservesAll();
 328   }
 329
 330   /// Add RequiredPass into list of lower level passes required by pass P.
 331   /// RequiredPass is run on the fly by Pass Manager when P requests it
 332   /// through getAnalysis interface.
 333   void addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass) override;
 334
 335   /// Return function pass corresponding to PassInfo PI, that is
 336   /// required by module pass MP. Instantiate analysis pass, by using
 337   /// its runOnFunction() for function F.
 338   Pass* getOnTheFlyPass(Pass *MP, AnalysisID PI, Function &F) override;
 339
 340   StringRef getPassName() const override { return "Module Pass Manager"; }
 341
 342   PMDataManager *getAsPMDataManager() override { return this; }
 343   Pass *getAsPass() override { return this; }
 344
 345   // Print passes managed by this manager
 346   void dumpPassStructure(unsigned Offset) override {
 347     dbgs().indent(Offset*2) << "ModulePass Manager\n";
 348     for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
 349       ModulePass *MP = getContainedPass(Index);
 350       MP->dumpPassStructure(Offset + 1);
 351       std::map<Pass *, FunctionPassManagerImpl *>::const_iterator I =
 352         OnTheFlyManagers.find(MP);
 353       if (I != OnTheFlyManagers.end())
 354         I->second->dumpPassStructure(Offset + 2);
 355       dumpLastUses(MP, Offset+1);
 356     }
 357   }
 358
 359   ModulePass *getContainedPass(unsigned N) {
 360     assert(N < PassVector.size() && "Pass number out of range!");
 361     return static_cast<ModulePass *>(PassVector[N]);
 362   }
 363
 364   PassManagerType getPassManagerType() const override {
 365     return PMT_ModulePassManager;
 366   }
 367
 368  private:
 369   /// Collection of on the fly FPPassManagers. These managers manage
 370   /// function passes that are required by module passes.
 371   std::map<Pass *, FunctionPassManagerImpl *> OnTheFlyManagers;
 372 };
 373
 374 char MPPassManager::ID = 0;
 375 } // End anonymous namespace
 376
 377 namespace llvm {
 378 namespace legacy {
 379 //===----------------------------------------------------------------------===//
 380 // PassManagerImpl
 381 //
 382
 383 /// PassManagerImpl manages MPPassManagers
 384 class PassManagerImpl : public Pass,
 385                         public PMDataManager,
 386                         public PMTopLevelManager {
 387   virtual void anchor();
 388
 389 public:
 390   static char ID;
 391   explicit PassManagerImpl() :
 392     Pass(PT_PassManager, ID), PMDataManager(),
 393                               PMTopLevelManager(new MPPassManager()) {}
 394
 395   /// \copydoc PassManager::add()
 396   void add(Pass *P) {
 397     schedulePass(P);
 398   }
 399
 400   /// createPrinterPass - Get a module printer pass.
 401   Pass *createPrinterPass(raw_ostream &O,
 402                           const std::string &Banner) const override {
 403     return createPrintModulePass(O, Banner);
 404   }
 405
 406   /// run - Execute all of the passes scheduled for execution.  Keep track of
 407   /// whether any of the passes modifies the module, and if so, return true.
 408   bool run(Module &M);
 409
 410   using llvm::Pass::doInitialization;
 411   using llvm::Pass::doFinalization;
 412
 413   /// Pass Manager itself does not invalidate any analysis info.
 414   void getAnalysisUsage(AnalysisUsage &Info) const override {
 415     Info.setPreservesAll();
 416   }
 417
 418   PMDataManager *getAsPMDataManager() override { return this; }
 419   Pass *getAsPass() override { return this; }
 420   PassManagerType getTopLevelPassManagerType() override {
 421     return PMT_ModulePassManager;
 422   }
 423
 424   MPPassManager *getContainedManager(unsigned N) {
 425     assert(N < PassManagers.size() && "Pass number out of range!");
 426     MPPassManager *MP = static_cast<MPPassManager *>(PassManagers[N]);
 427     return MP;
 428   }
 429 };
 430
 431 void PassManagerImpl::anchor() {}
 432
 433 char PassManagerImpl::ID = 0;
 434 } // End of legacy namespace
 435 } // End of llvm namespace
 436
 437 namespace {
 438
 439 //===----------------------------------------------------------------------===//
 440 /// TimingInfo Class - This class is used to calculate information about the
 441 /// amount of time each pass takes to execute.  This only happens when
 442 /// -time-passes is enabled on the command line.
 443 ///
 444
 445 static ManagedStatic<sys::SmartMutex<true> > TimingInfoMutex;
 446
 447 class TimingInfo {
 448   DenseMap<Pass*, Timer*> TimingData;
 449   TimerGroup TG;
 450 public:
 451   // Use 'create' member to get this.
 452   TimingInfo() : TG("pass", "... Pass execution timing report ...") {}
 453
 454   // TimingDtor - Print out information about timing information
 455   ~TimingInfo() {
 456     // Delete all of the timers, which accumulate their info into the
 457     // TimerGroup.
 458     for (auto &I : TimingData)
 459       delete I.second;
 460     // TimerGroup is deleted next, printing the report.
 461   }
 462
 463   // createTheTimeInfo - This method either initializes the TheTimeInfo pointer
 464   // to a non-null value (if the -time-passes option is enabled) or it leaves it
 465   // null.  It may be called multiple times.
 466   static void createTheTimeInfo();
 467
 468   /// getPassTimer - Return the timer for the specified pass if it exists.
 469   Timer *getPassTimer(Pass *P) {
 470     if (P->getAsPMDataManager())
 471       return nullptr;
 472
 473     sys::SmartScopedLock<true> Lock(*TimingInfoMutex);
 474     Timer *&T = TimingData[P];
 475     if (!T) {
 476       StringRef PassName = P->getPassName();
 477       T = new Timer(PassName, PassName, TG);
 478     }
 479     return T;
 480   }
 481 };
 482
 483 } // End of anon namespace
 484
 485 static TimingInfo *TheTimeInfo;
 486
 487 //===----------------------------------------------------------------------===//
 488 // PMTopLevelManager implementation
 489
 490 /// Initialize top level manager. Create first pass manager.
 491 PMTopLevelManager::PMTopLevelManager(PMDataManager *PMDM) {
 492   PMDM->setTopLevelManager(this);
 493   addPassManager(PMDM);
 494   activeStack.push(PMDM);
 495 }
 496
 497 /// Set pass P as the last user of the given analysis passes.
 498 void
 499 PMTopLevelManager::setLastUser(ArrayRef<Pass*> AnalysisPasses, Pass *P) {
 500   unsigned PDepth = 0;
 501   if (P->getResolver())
 502     PDepth = P->getResolver()->getPMDataManager().getDepth();
 503
 504   for (Pass *AP : AnalysisPasses) {
 505     LastUser[AP] = P;
 506
 507     if (P == AP)
 508       continue;
 509
 510     // Update the last users of passes that are required transitive by AP.
 511     AnalysisUsage *AnUsage = findAnalysisUsage(AP);
 512     const AnalysisUsage::VectorType &IDs = AnUsage->getRequiredTransitiveSet();
 513     SmallVector<Pass *, 12> LastUses;
 514     SmallVector<Pass *, 12> LastPMUses;
 515     for (AnalysisID ID : IDs) {
 516       Pass *AnalysisPass = findAnalysisPass(ID);
 517       assert(AnalysisPass && "Expected analysis pass to exist.");
 518       AnalysisResolver *AR = AnalysisPass->getResolver();
 519       assert(AR && "Expected analysis resolver to exist.");
 520       unsigned APDepth = AR->getPMDataManager().getDepth();
 521
 522       if (PDepth == APDepth)
 523         LastUses.push_back(AnalysisPass);
 524       else if (PDepth > APDepth)
 525         LastPMUses.push_back(AnalysisPass);
 526     }
 527
 528     setLastUser(LastUses, P);
 529
 530     // If this pass has a corresponding pass manager, push higher level
 531     // analysis to this pass manager.
 532     if (P->getResolver())
 533       setLastUser(LastPMUses, P->getResolver()->getPMDataManager().getAsPass());
 534
 535
 536     // If AP is the last user of other passes then make P last user of
 537     // such passes.
 538     for (auto LU : LastUser) {
 539       if (LU.second == AP)
 540         // DenseMap iterator is not invalidated here because
 541         // this is just updating existing entries.
 542         LastUser[LU.first] = P;
 543     }
 544   }
 545 }
 546
 547 /// Collect passes whose last user is P
 548 void PMTopLevelManager::collectLastUses(SmallVectorImpl<Pass *> &LastUses,
 549                                         Pass *P) {
 550   DenseMap<Pass *, SmallPtrSet<Pass *, 8> >::iterator DMI =
 551     InversedLastUser.find(P);
 552   if (DMI == InversedLastUser.end())
 553     return;
 554
 555   SmallPtrSet<Pass *, 8> &LU = DMI->second;
 556   for (Pass *LUP : LU) {
 557     LastUses.push_back(LUP);
 558   }
 559
 560 }
 561
 562 AnalysisUsage *PMTopLevelManager::findAnalysisUsage(Pass *P) {
 563   AnalysisUsage *AnUsage = nullptr;
 564   auto DMI = AnUsageMap.find(P);
 565   if (DMI != AnUsageMap.end())
 566     AnUsage = DMI->second;
 567   else {
 568     // Look up the analysis usage from the pass instance (different instances
 569     // of the same pass can produce different results), but unique the
 570     // resulting object to reduce memory usage.  This helps to greatly reduce
 571     // memory usage when we have many instances of only a few pass types
 572     // (e.g. instcombine, simplifycfg, etc...) which tend to share a fixed set
 573     // of dependencies.
 574     AnalysisUsage AU;
 575     P->getAnalysisUsage(AU);
 576
 577     AUFoldingSetNode* Node = nullptr;
 578     FoldingSetNodeID ID;
 579     AUFoldingSetNode::Profile(ID, AU);
 580     void *IP = nullptr;
 581     if (auto *N = UniqueAnalysisUsages.FindNodeOrInsertPos(ID, IP))
 582       Node = N;
 583     else {
 584       Node = new (AUFoldingSetNodeAllocator.Allocate()) AUFoldingSetNode(AU);
 585       UniqueAnalysisUsages.InsertNode(Node, IP);
 586     }
 587     assert(Node && "cached analysis usage must be non null");
 588
 589     AnUsageMap[P] = &Node->AU;
 590     AnUsage = &Node->AU;;
 591   }
 592   return AnUsage;
 593 }
 594
 595 /// Schedule pass P for execution. Make sure that passes required by
 596 /// P are run before P is run. Update analysis info maintained by
 597 /// the manager. Remove dead passes. This is a recursive function.
 598 void PMTopLevelManager::schedulePass(Pass *P) {
 599
 600   // TODO : Allocate function manager for this pass, other wise required set
 601   // may be inserted into previous function manager
 602
 603   // Give pass a chance to prepare the stage.
 604   P->preparePassManager(activeStack);
 605
 606   // If P is an analysis pass and it is available then do not
 607   // generate the analysis again. Stale analysis info should not be
 608   // available at this point.
 609   const PassInfo *PI = findAnalysisPassInfo(P->getPassID());
 610   if (PI && PI->isAnalysis() && findAnalysisPass(P->getPassID())) {
 611     delete P;
 612     return;
 613   }
 614
 615   AnalysisUsage *AnUsage = findAnalysisUsage(P);
 616
 617   bool checkAnalysis = true;
 618   while (checkAnalysis) {
 619     checkAnalysis = false;
 620
 621     const AnalysisUsage::VectorType &RequiredSet = AnUsage->getRequiredSet();
 622     for (AnalysisUsage::VectorType::const_iterator I = RequiredSet.begin(),
 623            E = RequiredSet.end(); I != E; ++I) {
 624
 625       Pass *AnalysisPass = findAnalysisPass(*I);
 626       if (!AnalysisPass) {
 627         const PassInfo *PI = findAnalysisPassInfo(*I);
 628
 629         if (!PI) {
 630           // Pass P is not in the global PassRegistry
 631           dbgs() << "Pass '"  << P->getPassName() << "' is not initialized." << "\n";
 632           dbgs() << "Verify if there is a pass dependency cycle." << "\n";
 633           dbgs() << "Required Passes:" << "\n";
 634           for (AnalysisUsage::VectorType::const_iterator I2 = RequiredSet.begin(),
 635                  E = RequiredSet.end(); I2 != E && I2 != I; ++I2) {
 636             Pass *AnalysisPass2 = findAnalysisPass(*I2);
 637             if (AnalysisPass2) {
 638               dbgs() << "\t" << AnalysisPass2->getPassName() << "\n";
 639             } else {
 640               dbgs() << "\t"   << "Error: Required pass not found! Possible causes:"  << "\n";
 641               dbgs() << "\t\t" << "- Pass misconfiguration (e.g.: missing macros)"    << "\n";
 642               dbgs() << "\t\t" << "- Corruption of the global PassRegistry"           << "\n";
 643             }
 644           }
 645         }
 646
 647         assert(PI && "Expected required passes to be initialized");
 648         AnalysisPass = PI->createPass();
 649         if (P->getPotentialPassManagerType () ==
 650             AnalysisPass->getPotentialPassManagerType())
 651           // Schedule analysis pass that is managed by the same pass manager.
 652           schedulePass(AnalysisPass);
 653         else if (P->getPotentialPassManagerType () >
 654                  AnalysisPass->getPotentialPassManagerType()) {
 655           // Schedule analysis pass that is managed by a new manager.
 656           schedulePass(AnalysisPass);
 657           // Recheck analysis passes to ensure that required analyses that
 658           // are already checked are still available.
 659           checkAnalysis = true;
 660         } else
 661           // Do not schedule this analysis. Lower level analysis
 662           // passes are run on the fly.
 663           delete AnalysisPass;
 664       }
 665     }
 666   }
 667
 668   // Now all required passes are available.
 669   if (ImmutablePass *IP = P->getAsImmutablePass()) {
 670     // P is a immutable pass and it will be managed by this
 671     // top level manager. Set up analysis resolver to connect them.
 672     PMDataManager *DM = getAsPMDataManager();
 673     AnalysisResolver *AR = new AnalysisResolver(*DM);
 674     P->setResolver(AR);
 675     DM->initializeAnalysisImpl(P);
 676     addImmutablePass(IP);
 677     DM->recordAvailableAnalysis(IP);
 678     return;
 679   }
 680
 681   if (PI && !PI->isAnalysis() && ShouldPrintBeforePass(PI)) {
 682     Pass *PP = P->createPrinterPass(
 683         dbgs(), ("*** IR Dump Before " + P->getPassName() + " ***").str());
 684     PP->assignPassManager(activeStack, getTopLevelPassManagerType());
 685   }
 686
 687   // Add the requested pass to the best available pass manager.
 688   P->assignPassManager(activeStack, getTopLevelPassManagerType());
 689
 690   if (PI && !PI->isAnalysis() && ShouldPrintAfterPass(PI)) {
 691     Pass *PP = P->createPrinterPass(
 692         dbgs(), ("*** IR Dump After " + P->getPassName() + " ***").str());
 693     PP->assignPassManager(activeStack, getTopLevelPassManagerType());
 694   }
 695 }
 696
 697 /// Find the pass that implements Analysis AID. Search immutable
 698 /// passes and all pass managers. If desired pass is not found
 699 /// then return NULL.
 700 Pass *PMTopLevelManager::findAnalysisPass(AnalysisID AID) {
 701   // For immutable passes we have a direct mapping from ID to pass, so check
 702   // that first.
 703   if (Pass *P = ImmutablePassMap.lookup(AID))
 704     return P;
 705
 706   // Check pass managers
 707   for (PMDataManager *PassManager : PassManagers)
 708     if (Pass *P = PassManager->findAnalysisPass(AID, false))
 709       return P;
 710
 711   // Check other pass managers
 712   for (PMDataManager *IndirectPassManager : IndirectPassManagers)
 713     if (Pass *P = IndirectPassManager->findAnalysisPass(AID, false))
 714       return P;
 715
 716   return nullptr;
 717 }
 718
 719 const PassInfo *PMTopLevelManager::findAnalysisPassInfo(AnalysisID AID) const {
 720   const PassInfo *&PI = AnalysisPassInfos[AID];
 721   if (!PI)
 722     PI = PassRegistry::getPassRegistry()->getPassInfo(AID);
 723   else
 724     assert(PI == PassRegistry::getPassRegistry()->getPassInfo(AID) &&
 725            "The pass info pointer changed for an analysis ID!");
 726
 727   return PI;
 728 }
 729
 730 void PMTopLevelManager::addImmutablePass(ImmutablePass *P) {
 731   P->initializePass();
 732   ImmutablePasses.push_back(P);
 733
 734   // Add this pass to the map from its analysis ID. We clobber any prior runs
 735   // of the pass in the map so that the last one added is the one found when
 736   // doing lookups.
 737   AnalysisID AID = P->getPassID();
 738   ImmutablePassMap[AID] = P;
 739
 740   // Also add any interfaces implemented by the immutable pass to the map for
 741   // fast lookup.
 742   const PassInfo *PassInf = findAnalysisPassInfo(AID);
 743   assert(PassInf && "Expected all immutable passes to be initialized");
 744   for (const PassInfo *ImmPI : PassInf->getInterfacesImplemented())
 745     ImmutablePassMap[ImmPI->getTypeInfo()] = P;
 746 }
 747
 748 // Print passes managed by this top level manager.
 749 void PMTopLevelManager::dumpPasses() const {
 750
 751   if (PassDebugging < Structure)
 752     return;
 753
 754   // Print out the immutable passes
 755   for (unsigned i = 0, e = ImmutablePasses.size(); i != e; ++i) {
 756     ImmutablePasses[i]->dumpPassStructure(0);
 757   }
 758
 759   // Every class that derives from PMDataManager also derives from Pass
 760   // (sometimes indirectly), but there's no inheritance relationship
 761   // between PMDataManager and Pass, so we have to getAsPass to get
 762   // from a PMDataManager* to a Pass*.
 763   for (PMDataManager *Manager : PassManagers)
 764     Manager->getAsPass()->dumpPassStructure(1);
 765 }
 766
 767 void PMTopLevelManager::dumpArguments() const {
 768
 769   if (PassDebugging < Arguments)
 770     return;
 771
 772   dbgs() << "Pass Arguments: ";
 773   for (ImmutablePass *P : ImmutablePasses)
 774     if (const PassInfo *PI = findAnalysisPassInfo(P->getPassID())) {
 775       assert(PI && "Expected all immutable passes to be initialized");
 776       if (!PI->isAnalysisGroup())
 777         dbgs() << " -" << PI->getPassArgument();
 778     }
 779   for (PMDataManager *PM : PassManagers)
 780     PM->dumpPassArguments();
 781   dbgs() << "\n";
 782 }
 783
 784 void PMTopLevelManager::initializeAllAnalysisInfo() {
 785   for (PMDataManager *PM : PassManagers)
 786     PM->initializeAnalysisInfo();
 787
 788   // Initailize other pass managers
 789   for (PMDataManager *IPM : IndirectPassManagers)
 790     IPM->initializeAnalysisInfo();
 791
 792   for (auto LU : LastUser) {
 793     SmallPtrSet<Pass *, 8> &L = InversedLastUser[LU.second];
 794     L.insert(LU.first);
 795   }
 796 }
 797
 798 /// Destructor
 799 PMTopLevelManager::~PMTopLevelManager() {
 800   for (PMDataManager *PM : PassManagers)
 801     delete PM;
 802
 803   for (ImmutablePass *P : ImmutablePasses)
 804     delete P;
 805 }
 806
 807 //===----------------------------------------------------------------------===//
 808 // PMDataManager implementation
 809
 810 /// Augement AvailableAnalysis by adding analysis made available by pass P.
 811 void PMDataManager::recordAvailableAnalysis(Pass *P) {
 812   AnalysisID PI = P->getPassID();
 813
 814   AvailableAnalysis[PI] = P;
 815
 816   assert(!AvailableAnalysis.empty());
 817
 818   // This pass is the current implementation of all of the interfaces it
 819   // implements as well.
 820   const PassInfo *PInf = TPM->findAnalysisPassInfo(PI);
 821   if (!PInf) return;
 822   const std::vector<const PassInfo*> &II = PInf->getInterfacesImplemented();
 823   for (unsigned i = 0, e = II.size(); i != e; ++i)
 824     AvailableAnalysis[II[i]->getTypeInfo()] = P;
 825 }
 826
 827 // Return true if P preserves high level analysis used by other
 828 // passes managed by this manager
 829 bool PMDataManager::preserveHigherLevelAnalysis(Pass *P) {
 830   AnalysisUsage *AnUsage = TPM->findAnalysisUsage(P);
 831   if (AnUsage->getPreservesAll())
 832     return true;
 833
 834   const AnalysisUsage::VectorType &PreservedSet = AnUsage->getPreservedSet();
 835   for (Pass *P1 : HigherLevelAnalysis) {
 836     if (P1->getAsImmutablePass() == nullptr &&
 837         !is_contained(PreservedSet, P1->getPassID()))
 838       return false;
 839   }
 840
 841   return true;
 842 }
 843
 844 /// verifyPreservedAnalysis -- Verify analysis preserved by pass P.
 845 void PMDataManager::verifyPreservedAnalysis(Pass *P) {
 846   // Don't do this unless assertions are enabled.
 847 #ifdef NDEBUG
 848   return;
 849 #endif
 850   AnalysisUsage *AnUsage = TPM->findAnalysisUsage(P);
 851   const AnalysisUsage::VectorType &PreservedSet = AnUsage->getPreservedSet();
 852
 853   // Verify preserved analysis
 854   for (AnalysisID AID : PreservedSet) {
 855     if (Pass *AP = findAnalysisPass(AID, true)) {
 856       TimeRegion PassTimer(getPassTimer(AP));
 857       AP->verifyAnalysis();
 858     }
 859   }
 860 }
 861
 862 /// Remove Analysis not preserved by Pass P
 863 void PMDataManager::removeNotPreservedAnalysis(Pass *P) {
 864   AnalysisUsage *AnUsage = TPM->findAnalysisUsage(P);
 865   if (AnUsage->getPreservesAll())
 866     return;
 867
 868   const AnalysisUsage::VectorType &PreservedSet = AnUsage->getPreservedSet();
 869   for (DenseMap<AnalysisID, Pass*>::iterator I = AvailableAnalysis.begin(),
 870          E = AvailableAnalysis.end(); I != E; ) {
 871     DenseMap<AnalysisID, Pass*>::iterator Info = I++;
 872     if (Info->second->getAsImmutablePass() == nullptr &&
 873         !is_contained(PreservedSet, Info->first)) {
 874       // Remove this analysis
 875       if (PassDebugging >= Details) {
 876         Pass *S = Info->second;
 877         dbgs() << " -- '" <<  P->getPassName() << "' is not preserving '";
 878         dbgs() << S->getPassName() << "'\n";
 879       }
 880       AvailableAnalysis.erase(Info);
 881     }
 882   }
 883
 884   // Check inherited analysis also. If P is not preserving analysis
 885   // provided by parent manager then remove it here.
 886   for (unsigned Index = 0; Index < PMT_Last; ++Index) {
 887
 888     if (!InheritedAnalysis[Index])
 889       continue;
 890
 891     for (DenseMap<AnalysisID, Pass*>::iterator
 892            I = InheritedAnalysis[Index]->begin(),
 893            E = InheritedAnalysis[Index]->end(); I != E; ) {
 894       DenseMap<AnalysisID, Pass *>::iterator Info = I++;
 895       if (Info->second->getAsImmutablePass() == nullptr &&
 896           !is_contained(PreservedSet, Info->first)) {
 897         // Remove this analysis
 898         if (PassDebugging >= Details) {
 899           Pass *S = Info->second;
 900           dbgs() << " -- '" <<  P->getPassName() << "' is not preserving '";
 901           dbgs() << S->getPassName() << "'\n";
 902         }
 903         InheritedAnalysis[Index]->erase(Info);
 904       }
 905     }
 906   }
 907 }
 908
 909 /// Remove analysis passes that are not used any longer
 910 void PMDataManager::removeDeadPasses(Pass *P, StringRef Msg,
 911                                      enum PassDebuggingString DBG_STR) {
 912
 913   SmallVector<Pass *, 12> DeadPasses;
 914
 915   // If this is a on the fly manager then it does not have TPM.
 916   if (!TPM)
 917     return;
 918
 919   TPM->collectLastUses(DeadPasses, P);
 920
 921   if (PassDebugging >= Details && !DeadPasses.empty()) {
 922     dbgs() << " -*- '" <<  P->getPassName();
 923     dbgs() << "' is the last user of following pass instances.";
 924     dbgs() << " Free these instances\n";
 925   }
 926
 927   for (Pass *P : DeadPasses)
 928     freePass(P, Msg, DBG_STR);
 929 }
 930
 931 void PMDataManager::freePass(Pass *P, StringRef Msg,
 932                              enum PassDebuggingString DBG_STR) {
 933   dumpPassInfo(P, FREEING_MSG, DBG_STR, Msg);
 934
 935   {
 936     // If the pass crashes releasing memory, remember this.
 937     PassManagerPrettyStackEntry X(P);
 938     TimeRegion PassTimer(getPassTimer(P));
 939
 940     P->releaseMemory();
 941   }
 942
 943   AnalysisID PI = P->getPassID();
 944   if (const PassInfo *PInf = TPM->findAnalysisPassInfo(PI)) {
 945     // Remove the pass itself (if it is not already removed).
 946     AvailableAnalysis.erase(PI);
 947
 948     // Remove all interfaces this pass implements, for which it is also
 949     // listed as the available implementation.
 950     const std::vector<const PassInfo*> &II = PInf->getInterfacesImplemented();
 951     for (unsigned i = 0, e = II.size(); i != e; ++i) {
 952       DenseMap<AnalysisID, Pass*>::iterator Pos =
 953         AvailableAnalysis.find(II[i]->getTypeInfo());
 954       if (Pos != AvailableAnalysis.end() && Pos->second == P)
 955         AvailableAnalysis.erase(Pos);
 956     }
 957   }
 958 }
 959
 960 /// Add pass P into the PassVector. Update
 961 /// AvailableAnalysis appropriately if ProcessAnalysis is true.
 962 void PMDataManager::add(Pass *P, bool ProcessAnalysis) {
 963   // This manager is going to manage pass P. Set up analysis resolver
 964   // to connect them.
 965   AnalysisResolver *AR = new AnalysisResolver(*this);
 966   P->setResolver(AR);
 967
 968   // If a FunctionPass F is the last user of ModulePass info M
 969   // then the F's manager, not F, records itself as a last user of M.
 970   SmallVector<Pass *, 12> TransferLastUses;
 971
 972   if (!ProcessAnalysis) {
 973     // Add pass
 974     PassVector.push_back(P);
 975     return;
 976   }
 977
 978   // At the moment, this pass is the last user of all required passes.
 979   SmallVector<Pass *, 12> LastUses;
 980   SmallVector<Pass *, 8> UsedPasses;
 981   SmallVector<AnalysisID, 8> ReqAnalysisNotAvailable;
 982
 983   unsigned PDepth = this->getDepth();
 984
 985   collectRequiredAndUsedAnalyses(UsedPasses, ReqAnalysisNotAvailable, P);
 986   for (Pass *PUsed : UsedPasses) {
 987     unsigned RDepth = 0;
 988
 989     assert(PUsed->getResolver() && "Analysis Resolver is not set");
 990     PMDataManager &DM = PUsed->getResolver()->getPMDataManager();
 991     RDepth = DM.getDepth();
 992
 993     if (PDepth == RDepth)
 994       LastUses.push_back(PUsed);
 995     else if (PDepth > RDepth) {
 996       // Let the parent claim responsibility of last use
 997       TransferLastUses.push_back(PUsed);
 998       // Keep track of higher level analysis used by this manager.
 999       HigherLevelAnalysis.push_back(PUsed);
1000     } else
1001       llvm_unreachable("Unable to accommodate Used Pass");
1002   }
1003
1004   // Set P as P's last user until someone starts using P.
1005   // However, if P is a Pass Manager then it does not need
1006   // to record its last user.
1007   if (!P->getAsPMDataManager())
1008     LastUses.push_back(P);
1009   TPM->setLastUser(LastUses, P);
1010
1011   if (!TransferLastUses.empty()) {
1012     Pass *My_PM = getAsPass();
1013     TPM->setLastUser(TransferLastUses, My_PM);
1014     TransferLastUses.clear();
1015   }
1016
1017   // Now, take care of required analyses that are not available.
1018   for (AnalysisID ID : ReqAnalysisNotAvailable) {
1019     const PassInfo *PI = TPM->findAnalysisPassInfo(ID);
1020     Pass *AnalysisPass = PI->createPass();
1021     this->addLowerLevelRequiredPass(P, AnalysisPass);
1022   }
1023
1024   // Take a note of analysis required and made available by this pass.
1025   // Remove the analysis not preserved by this pass
1026   removeNotPreservedAnalysis(P);
1027   recordAvailableAnalysis(P);
1028
1029   // Add pass
1030   PassVector.push_back(P);
1031 }
1032
1033
1034 /// Populate UP with analysis pass that are used or required by
1035 /// pass P and are available. Populate RP_NotAvail with analysis
1036 /// pass that are required by pass P but are not available.
1037 void PMDataManager::collectRequiredAndUsedAnalyses(
1038     SmallVectorImpl<Pass *> &UP, SmallVectorImpl<AnalysisID> &RP_NotAvail,
1039     Pass *P) {
1040   AnalysisUsage *AnUsage = TPM->findAnalysisUsage(P);
1041
1042   for (const auto &UsedID : AnUsage->getUsedSet())
1043     if (Pass *AnalysisPass = findAnalysisPass(UsedID, true))
1044       UP.push_back(AnalysisPass);
1045
1046   for (const auto &RequiredID : AnUsage->getRequiredSet())
1047     if (Pass *AnalysisPass = findAnalysisPass(RequiredID, true))
1048       UP.push_back(AnalysisPass);
1049     else
1050       RP_NotAvail.push_back(RequiredID);
1051
1052   for (const auto &RequiredID : AnUsage->getRequiredTransitiveSet())
1053     if (Pass *AnalysisPass = findAnalysisPass(RequiredID, true))
1054       UP.push_back(AnalysisPass);
1055     else
1056       RP_NotAvail.push_back(RequiredID);
1057 }
1058
1059 // All Required analyses should be available to the pass as it runs!  Here
1060 // we fill in the AnalysisImpls member of the pass so that it can
1061 // successfully use the getAnalysis() method to retrieve the
1062 // implementations it needs.
1063 //
1064 void PMDataManager::initializeAnalysisImpl(Pass *P) {
1065   AnalysisUsage *AnUsage = TPM->findAnalysisUsage(P);
1066
1067   for (AnalysisUsage::VectorType::const_iterator
1068          I = AnUsage->getRequiredSet().begin(),
1069          E = AnUsage->getRequiredSet().end(); I != E; ++I) {
1070     Pass *Impl = findAnalysisPass(*I, true);
1071     if (!Impl)
1072       // This may be analysis pass that is initialized on the fly.
1073       // If that is not the case then it will raise an assert when it is used.
1074       continue;
1075     AnalysisResolver *AR = P->getResolver();
1076     assert(AR && "Analysis Resolver is not set");
1077     AR->addAnalysisImplsPair(*I, Impl);
1078   }
1079 }
1080
1081 /// Find the pass that implements Analysis AID. If desired pass is not found
1082 /// then return NULL.
1083 Pass *PMDataManager::findAnalysisPass(AnalysisID AID, bool SearchParent) {
1084
1085   // Check if AvailableAnalysis map has one entry.
1086   DenseMap<AnalysisID, Pass*>::const_iterator I =  AvailableAnalysis.find(AID);
1087
1088   if (I != AvailableAnalysis.end())
1089     return I->second;
1090
1091   // Search Parents through TopLevelManager
1092   if (SearchParent)
1093     return TPM->findAnalysisPass(AID);
1094
1095   return nullptr;
1096 }
1097
1098 // Print list of passes that are last used by P.
1099 void PMDataManager::dumpLastUses(Pass *P, unsigned Offset) const{
1100
1101   SmallVector<Pass *, 12> LUses;
1102
1103   // If this is a on the fly manager then it does not have TPM.
1104   if (!TPM)
1105     return;
1106
1107   TPM->collectLastUses(LUses, P);
1108
1109   for (SmallVectorImpl<Pass *>::iterator I = LUses.begin(),
1110          E = LUses.end(); I != E; ++I) {
1111     dbgs() << "--" << std::string(Offset*2, ' ');
1112     (*I)->dumpPassStructure(0);
1113   }
1114 }
1115
1116 void PMDataManager::dumpPassArguments() const {
1117   for (SmallVectorImpl<Pass *>::const_iterator I = PassVector.begin(),
1118         E = PassVector.end(); I != E; ++I) {
1119     if (PMDataManager *PMD = (*I)->getAsPMDataManager())
1120       PMD->dumpPassArguments();
1121     else
1122       if (const PassInfo *PI =
1123             TPM->findAnalysisPassInfo((*I)->getPassID()))
1124         if (!PI->isAnalysisGroup())
1125           dbgs() << " -" << PI->getPassArgument();
1126   }
1127 }
1128
1129 void PMDataManager::dumpPassInfo(Pass *P, enum PassDebuggingString S1,
1130                                  enum PassDebuggingString S2,
1131                                  StringRef Msg) {
1132   if (PassDebugging < Executions)
1133     return;
1134   dbgs() << "[" << std::chrono::system_clock::now() << "] " << (void *)this
1135          << std::string(getDepth() * 2 + 1, ' ');
1136   switch (S1) {
1137   case EXECUTION_MSG:
1138     dbgs() << "Executing Pass '" << P->getPassName();
1139     break;
1140   case MODIFICATION_MSG:
1141     dbgs() << "Made Modification '" << P->getPassName();
1142     break;
1143   case FREEING_MSG:
1144     dbgs() << " Freeing Pass '" << P->getPassName();
1145     break;
1146   default:
1147     break;
1148   }
1149   switch (S2) {
1150   case ON_BASICBLOCK_MSG:
1151     dbgs() << "' on BasicBlock '" << Msg << "'...\n";
1152     break;
1153   case ON_FUNCTION_MSG:
1154     dbgs() << "' on Function '" << Msg << "'...\n";
1155     break;
1156   case ON_MODULE_MSG:
1157     dbgs() << "' on Module '"  << Msg << "'...\n";
1158     break;
1159   case ON_REGION_MSG:
1160     dbgs() << "' on Region '"  << Msg << "'...\n";
1161     break;
1162   case ON_LOOP_MSG:
1163     dbgs() << "' on Loop '" << Msg << "'...\n";
1164     break;
1165   case ON_CG_MSG:
1166     dbgs() << "' on Call Graph Nodes '" << Msg << "'...\n";
1167     break;
1168   default:
1169     break;
1170   }
1171 }
1172
1173 void PMDataManager::dumpRequiredSet(const Pass *P) const {
1174   if (PassDebugging < Details)
1175     return;
1176
1177   AnalysisUsage analysisUsage;
1178   P->getAnalysisUsage(analysisUsage);
1179   dumpAnalysisUsage("Required", P, analysisUsage.getRequiredSet());
1180 }
1181
1182 void PMDataManager::dumpPreservedSet(const Pass *P) const {
1183   if (PassDebugging < Details)
1184     return;
1185
1186   AnalysisUsage analysisUsage;
1187   P->getAnalysisUsage(analysisUsage);
1188   dumpAnalysisUsage("Preserved", P, analysisUsage.getPreservedSet());
1189 }
1190
1191 void PMDataManager::dumpUsedSet(const Pass *P) const {
1192   if (PassDebugging < Details)
1193     return;
1194
1195   AnalysisUsage analysisUsage;
1196   P->getAnalysisUsage(analysisUsage);
1197   dumpAnalysisUsage("Used", P, analysisUsage.getUsedSet());
1198 }
1199
1200 void PMDataManager::dumpAnalysisUsage(StringRef Msg, const Pass *P,
1201                                    const AnalysisUsage::VectorType &Set) const {
1202   assert(PassDebugging >= Details);
1203   if (Set.empty())
1204     return;
1205   dbgs() << (const void*)P << std::string(getDepth()*2+3, ' ') << Msg << " Analyses:";
1206   for (unsigned i = 0; i != Set.size(); ++i) {
1207     if (i) dbgs() << ',';
1208     const PassInfo *PInf = TPM->findAnalysisPassInfo(Set[i]);
1209     if (!PInf) {
1210       // Some preserved passes, such as AliasAnalysis, may not be initialized by
1211       // all drivers.
1212       dbgs() << " Uninitialized Pass";
1213       continue;
1214     }
1215     dbgs() << ' ' << PInf->getPassName();
1216   }
1217   dbgs() << '\n';
1218 }
1219
1220 /// Add RequiredPass into list of lower level passes required by pass P.
1221 /// RequiredPass is run on the fly by Pass Manager when P requests it
1222 /// through getAnalysis interface.
1223 /// This should be handled by specific pass manager.
1224 void PMDataManager::addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass) {
1225   if (TPM) {
1226     TPM->dumpArguments();
1227     TPM->dumpPasses();
1228   }
1229
1230   // Module Level pass may required Function Level analysis info
1231   // (e.g. dominator info). Pass manager uses on the fly function pass manager
1232   // to provide this on demand. In that case, in Pass manager terminology,
1233   // module level pass is requiring lower level analysis info managed by
1234   // lower level pass manager.
1235
1236   // When Pass manager is not able to order required analysis info, Pass manager
1237   // checks whether any lower level manager will be able to provide this
1238   // analysis info on demand or not.
1239 #ifndef NDEBUG
1240   dbgs() << "Unable to schedule '" << RequiredPass->getPassName();
1241   dbgs() << "' required by '" << P->getPassName() << "'\n";
1242 #endif
1243   llvm_unreachable("Unable to schedule pass");
1244 }
1245
1246 Pass *PMDataManager::getOnTheFlyPass(Pass *P, AnalysisID PI, Function &F) {
1247   llvm_unreachable("Unable to find on the fly pass");
1248 }
1249
1250 // Destructor
1251 PMDataManager::~PMDataManager() {
1252   for (SmallVectorImpl<Pass *>::iterator I = PassVector.begin(),
1253          E = PassVector.end(); I != E; ++I)
1254     delete *I;
1255 }
1256
1257 //===----------------------------------------------------------------------===//
1258 // NOTE: Is this the right place to define this method ?
1259 // getAnalysisIfAvailable - Return analysis result or null if it doesn't exist.
1260 Pass *AnalysisResolver::getAnalysisIfAvailable(AnalysisID ID, bool dir) const {
1261   return PM.findAnalysisPass(ID, dir);
1262 }
1263
1264 Pass *AnalysisResolver::findImplPass(Pass *P, AnalysisID AnalysisPI,
1265                                      Function &F) {
1266   return PM.getOnTheFlyPass(P, AnalysisPI, F);
1267 }
1268
1269 //===----------------------------------------------------------------------===//
1270 // BBPassManager implementation
1271
1272 /// Execute all of the passes scheduled for execution by invoking
1273 /// runOnBasicBlock method.  Keep track of whether any of the passes modifies
1274 /// the function, and if so, return true.
1275 bool BBPassManager::runOnFunction(Function &F) {
1276   if (F.isDeclaration())
1277     return false;
1278
1279   bool Changed = doInitialization(F);
1280
1281   for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
1282     for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
1283       BasicBlockPass *BP = getContainedPass(Index);
1284       bool LocalChanged = false;
1285
1286       dumpPassInfo(BP, EXECUTION_MSG, ON_BASICBLOCK_MSG, I->getName());
1287       dumpRequiredSet(BP);
1288
1289       initializeAnalysisImpl(BP);
1290
1291       {
1292         // If the pass crashes, remember this.
1293         PassManagerPrettyStackEntry X(BP, *I);
1294         TimeRegion PassTimer(getPassTimer(BP));
1295
1296         LocalChanged |= BP->runOnBasicBlock(*I);
1297       }
1298
1299       Changed |= LocalChanged;
1300       if (LocalChanged)
1301         dumpPassInfo(BP, MODIFICATION_MSG, ON_BASICBLOCK_MSG,
1302                      I->getName());
1303       dumpPreservedSet(BP);
1304       dumpUsedSet(BP);
1305
1306       verifyPreservedAnalysis(BP);
1307       removeNotPreservedAnalysis(BP);
1308       recordAvailableAnalysis(BP);
1309       removeDeadPasses(BP, I->getName(), ON_BASICBLOCK_MSG);
1310     }
1311
1312   return doFinalization(F) || Changed;
1313 }
1314
1315 // Implement doInitialization and doFinalization
1316 bool BBPassManager::doInitialization(Module &M) {
1317   bool Changed = false;
1318
1319   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index)
1320     Changed |= getContainedPass(Index)->doInitialization(M);
1321
1322   return Changed;
1323 }
1324
1325 bool BBPassManager::doFinalization(Module &M) {
1326   bool Changed = false;
1327
1328   for (int Index = getNumContainedPasses() - 1; Index >= 0; --Index)
1329     Changed |= getContainedPass(Index)->doFinalization(M);
1330
1331   return Changed;
1332 }
1333
1334 bool BBPassManager::doInitialization(Function &F) {
1335   bool Changed = false;
1336
1337   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
1338     BasicBlockPass *BP = getContainedPass(Index);
1339     Changed |= BP->doInitialization(F);
1340   }
1341
1342   return Changed;
1343 }
1344
1345 bool BBPassManager::doFinalization(Function &F) {
1346   bool Changed = false;
1347
1348   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
1349     BasicBlockPass *BP = getContainedPass(Index);
1350     Changed |= BP->doFinalization(F);
1351   }
1352
1353   return Changed;
1354 }
1355
1356
1357 //===----------------------------------------------------------------------===//
1358 // FunctionPassManager implementation
1359
1360 /// Create new Function pass manager
1361 FunctionPassManager::FunctionPassManager(Module *m) : M(m) {
1362   FPM = new FunctionPassManagerImpl();
1363   // FPM is the top level manager.
1364   FPM->setTopLevelManager(FPM);
1365
1366   AnalysisResolver *AR = new AnalysisResolver(*FPM);
1367   FPM->setResolver(AR);
1368 }
1369
1370 FunctionPassManager::~FunctionPassManager() {
1371   delete FPM;
1372 }
1373
1374 void FunctionPassManager::add(Pass *P) {
1375   FPM->add(P);
1376 }
1377
1378 /// run - Execute all of the passes scheduled for execution.  Keep
1379 /// track of whether any of the passes modifies the function, and if
1380 /// so, return true.
1381 ///
1382 bool FunctionPassManager::run(Function &F) {
1383   handleAllErrors(F.materialize(), [&](ErrorInfoBase &EIB) {
1384     report_fatal_error("Error reading bitcode file: " + EIB.message());
1385   });
1386   return FPM->run(F);
1387 }
1388
1389
1390 /// doInitialization - Run all of the initializers for the function passes.
1391 ///
1392 bool FunctionPassManager::doInitialization() {
1393   return FPM->doInitialization(*M);
1394 }
1395
1396 /// doFinalization - Run all of the finalizers for the function passes.
1397 ///
1398 bool FunctionPassManager::doFinalization() {
1399   return FPM->doFinalization(*M);
1400 }
1401
1402 //===----------------------------------------------------------------------===//
1403 // FunctionPassManagerImpl implementation
1404 //
1405 bool FunctionPassManagerImpl::doInitialization(Module &M) {
1406   bool Changed = false;
1407
1408   dumpArguments();
1409   dumpPasses();
1410
1411   for (ImmutablePass *ImPass : getImmutablePasses())
1412     Changed |= ImPass->doInitialization(M);
1413
1414   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index)
1415     Changed |= getContainedManager(Index)->doInitialization(M);
1416
1417   return Changed;
1418 }
1419
1420 bool FunctionPassManagerImpl::doFinalization(Module &M) {
1421   bool Changed = false;
1422
1423   for (int Index = getNumContainedManagers() - 1; Index >= 0; --Index)
1424     Changed |= getContainedManager(Index)->doFinalization(M);
1425
1426   for (ImmutablePass *ImPass : getImmutablePasses())
1427     Changed |= ImPass->doFinalization(M);
1428
1429   return Changed;
1430 }
1431
1432 /// cleanup - After running all passes, clean up pass manager cache.
1433 void FPPassManager::cleanup() {
1434  for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
1435     FunctionPass *FP = getContainedPass(Index);
1436     AnalysisResolver *AR = FP->getResolver();
1437     assert(AR && "Analysis Resolver is not set");
1438     AR->clearAnalysisImpls();
1439  }
1440 }
1441
1442 void FunctionPassManagerImpl::releaseMemoryOnTheFly() {
1443   if (!wasRun)
1444     return;
1445   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index) {
1446     FPPassManager *FPPM = getContainedManager(Index);
1447     for (unsigned Index = 0; Index < FPPM->getNumContainedPasses(); ++Index) {
1448       FPPM->getContainedPass(Index)->releaseMemory();
1449     }
1450   }
1451   wasRun = false;
1452 }
1453
1454 // Execute all the passes managed by this top level manager.
1455 // Return true if any function is modified by a pass.
1456 bool FunctionPassManagerImpl::run(Function &F) {
1457   bool Changed = false;
1458   TimingInfo::createTheTimeInfo();
1459
1460   initializeAllAnalysisInfo();
1461   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index) {
1462     Changed |= getContainedManager(Index)->runOnFunction(F);
1463     F.getContext().yield();
1464   }
1465
1466   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index)
1467     getContainedManager(Index)->cleanup();
1468
1469   wasRun = true;
1470   return Changed;
1471 }
1472
1473 //===----------------------------------------------------------------------===//
1474 // FPPassManager implementation
1475
1476 char FPPassManager::ID = 0;
1477 /// Print passes managed by this manager
1478 void FPPassManager::dumpPassStructure(unsigned Offset) {
1479   dbgs().indent(Offset*2) << "FunctionPass Manager\n";
1480   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
1481     FunctionPass *FP = getContainedPass(Index);
1482     FP->dumpPassStructure(Offset + 1);
1483     dumpLastUses(FP, Offset+1);
1484   }
1485 }
1486
1487
1488 /// Execute all of the passes scheduled for execution by invoking
1489 /// runOnFunction method.  Keep track of whether any of the passes modifies
1490 /// the function, and if so, return true.
1491 bool FPPassManager::runOnFunction(Function &F) {
1492   if (F.isDeclaration())
1493     return false;
1494
1495   bool Changed = false;
1496
1497   // Collect inherited analysis from Module level pass manager.
1498   populateInheritedAnalysis(TPM->activeStack);
1499
1500   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
1501     FunctionPass *FP = getContainedPass(Index);
1502     bool LocalChanged = false;
1503
1504     dumpPassInfo(FP, EXECUTION_MSG, ON_FUNCTION_MSG, F.getName());
1505     dumpRequiredSet(FP);
1506
1507     initializeAnalysisImpl(FP);
1508
1509     {
1510       PassManagerPrettyStackEntry X(FP, F);
1511       TimeRegion PassTimer(getPassTimer(FP));
1512
1513       LocalChanged |= FP->runOnFunction(F);
1514     }
1515
1516     Changed |= LocalChanged;
1517     if (LocalChanged)
1518       dumpPassInfo(FP, MODIFICATION_MSG, ON_FUNCTION_MSG, F.getName());
1519     dumpPreservedSet(FP);
1520     dumpUsedSet(FP);
1521
1522     verifyPreservedAnalysis(FP);
1523     removeNotPreservedAnalysis(FP);
1524     recordAvailableAnalysis(FP);
1525     removeDeadPasses(FP, F.getName(), ON_FUNCTION_MSG);
1526   }
1527   return Changed;
1528 }
1529
1530 bool FPPassManager::runOnModule(Module &M) {
1531   bool Changed = false;
1532
1533   for (Function &F : M)
1534     Changed |= runOnFunction(F);
1535
1536   return Changed;
1537 }
1538
1539 bool FPPassManager::doInitialization(Module &M) {
1540   bool Changed = false;
1541
1542   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index)
1543     Changed |= getContainedPass(Index)->doInitialization(M);
1544
1545   return Changed;
1546 }
1547
1548 bool FPPassManager::doFinalization(Module &M) {
1549   bool Changed = false;
1550
1551   for (int Index = getNumContainedPasses() - 1; Index >= 0; --Index)
1552     Changed |= getContainedPass(Index)->doFinalization(M);
1553
1554   return Changed;
1555 }
1556
1557 //===----------------------------------------------------------------------===//
1558 // MPPassManager implementation
1559
1560 /// Execute all of the passes scheduled for execution by invoking
1561 /// runOnModule method.  Keep track of whether any of the passes modifies
1562 /// the module, and if so, return true.
1563 bool
1564 MPPassManager::runOnModule(Module &M) {
1565   bool Changed = false;
1566
1567   // Initialize on-the-fly passes
1568   for (auto &OnTheFlyManager : OnTheFlyManagers) {
1569     FunctionPassManagerImpl *FPP = OnTheFlyManager.second;
1570     Changed |= FPP->doInitialization(M);
1571   }
1572
1573   // Initialize module passes
1574   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index)
1575     Changed |= getContainedPass(Index)->doInitialization(M);
1576
1577   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
1578     ModulePass *MP = getContainedPass(Index);
1579     bool LocalChanged = false;
1580
1581     dumpPassInfo(MP, EXECUTION_MSG, ON_MODULE_MSG, M.getModuleIdentifier());
1582     dumpRequiredSet(MP);
1583
1584     initializeAnalysisImpl(MP);
1585
1586     {
1587       PassManagerPrettyStackEntry X(MP, M);
1588       TimeRegion PassTimer(getPassTimer(MP));
1589
1590       LocalChanged |= MP->runOnModule(M);
1591     }
1592
1593     Changed |= LocalChanged;
1594     if (LocalChanged)
1595       dumpPassInfo(MP, MODIFICATION_MSG, ON_MODULE_MSG,
1596                    M.getModuleIdentifier());
1597     dumpPreservedSet(MP);
1598     dumpUsedSet(MP);
1599
1600     verifyPreservedAnalysis(MP);
1601     removeNotPreservedAnalysis(MP);
1602     recordAvailableAnalysis(MP);
1603     removeDeadPasses(MP, M.getModuleIdentifier(), ON_MODULE_MSG);
1604   }
1605
1606   // Finalize module passes
1607   for (int Index = getNumContainedPasses() - 1; Index >= 0; --Index)
1608     Changed |= getContainedPass(Index)->doFinalization(M);
1609
1610   // Finalize on-the-fly passes
1611   for (auto &OnTheFlyManager : OnTheFlyManagers) {
1612     FunctionPassManagerImpl *FPP = OnTheFlyManager.second;
1613     // We don't know when is the last time an on-the-fly pass is run,
1614     // so we need to releaseMemory / finalize here
1615     FPP->releaseMemoryOnTheFly();
1616     Changed |= FPP->doFinalization(M);
1617   }
1618
1619   return Changed;
1620 }
1621
1622 /// Add RequiredPass into list of lower level passes required by pass P.
1623 /// RequiredPass is run on the fly by Pass Manager when P requests it
1624 /// through getAnalysis interface.
1625 void MPPassManager::addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass) {
1626   assert(P->getPotentialPassManagerType() == PMT_ModulePassManager &&
1627          "Unable to handle Pass that requires lower level Analysis pass");
1628   assert((P->getPotentialPassManagerType() <
1629           RequiredPass->getPotentialPassManagerType()) &&
1630          "Unable to handle Pass that requires lower level Analysis pass");
1631   if (!RequiredPass)
1632     return;
1633
1634   FunctionPassManagerImpl *FPP = OnTheFlyManagers[P];
1635   if (!FPP) {
1636     FPP = new FunctionPassManagerImpl();
1637     // FPP is the top level manager.
1638     FPP->setTopLevelManager(FPP);
1639
1640     OnTheFlyManagers[P] = FPP;
1641   }
1642   const PassInfo *RequiredPassPI =
1643       TPM->findAnalysisPassInfo(RequiredPass->getPassID());
1644
1645   Pass *FoundPass = nullptr;
1646   if (RequiredPassPI && RequiredPassPI->isAnalysis()) {
1647     FoundPass =
1648       ((PMTopLevelManager*)FPP)->findAnalysisPass(RequiredPass->getPassID());
1649   }
1650   if (!FoundPass) {
1651     FoundPass = RequiredPass;
1652     // This should be guaranteed to add RequiredPass to the passmanager given
1653     // that we checked for an available analysis above.
1654     FPP->add(RequiredPass);
1655   }
1656   // Register P as the last user of FoundPass or RequiredPass.
1657   SmallVector<Pass *, 1> LU;
1658   LU.push_back(FoundPass);
1659   FPP->setLastUser(LU,  P);
1660 }
1661
1662 /// Return function pass corresponding to PassInfo PI, that is
1663 /// required by module pass MP. Instantiate analysis pass, by using
1664 /// its runOnFunction() for function F.
1665 Pass* MPPassManager::getOnTheFlyPass(Pass *MP, AnalysisID PI, Function &F){
1666   FunctionPassManagerImpl *FPP = OnTheFlyManagers[MP];
1667   assert(FPP && "Unable to find on the fly pass");
1668
1669   FPP->releaseMemoryOnTheFly();
1670   FPP->run(F);
1671   return ((PMTopLevelManager*)FPP)->findAnalysisPass(PI);
1672 }
1673
1674
1675 //===----------------------------------------------------------------------===//
1676 // PassManagerImpl implementation
1677
1678 //
1679 /// run - Execute all of the passes scheduled for execution.  Keep track of
1680 /// whether any of the passes modifies the module, and if so, return true.
1681 bool PassManagerImpl::run(Module &M) {
1682   bool Changed = false;
1683   TimingInfo::createTheTimeInfo();
1684
1685   dumpArguments();
1686   dumpPasses();
1687
1688   for (ImmutablePass *ImPass : getImmutablePasses())
1689     Changed |= ImPass->doInitialization(M);
1690
1691   initializeAllAnalysisInfo();
1692   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index) {
1693     Changed |= getContainedManager(Index)->runOnModule(M);
1694     M.getContext().yield();
1695   }
1696
1697   for (ImmutablePass *ImPass : getImmutablePasses())
1698     Changed |= ImPass->doFinalization(M);
1699
1700   return Changed;
1701 }
1702
1703 //===----------------------------------------------------------------------===//
1704 // PassManager implementation
1705
1706 /// Create new pass manager
1707 PassManager::PassManager() {
1708   PM = new PassManagerImpl();
1709   // PM is the top level manager
1710   PM->setTopLevelManager(PM);
1711 }
1712
1713 PassManager::~PassManager() {
1714   delete PM;
1715 }
1716
1717 void PassManager::add(Pass *P) {
1718   PM->add(P);
1719 }
1720
1721 /// run - Execute all of the passes scheduled for execution.  Keep track of
1722 /// whether any of the passes modifies the module, and if so, return true.
1723 bool PassManager::run(Module &M) {
1724   return PM->run(M);
1725 }
1726
1727 //===----------------------------------------------------------------------===//
1728 // TimingInfo implementation
1729
1730 bool llvm::TimePassesIsEnabled = false;
1731 static cl::opt<bool,true>
1732 EnableTiming("time-passes", cl::location(TimePassesIsEnabled),
1733             cl::desc("Time each pass, printing elapsed time for each on exit"));
1734
1735 // createTheTimeInfo - This method either initializes the TheTimeInfo pointer to
1736 // a non-null value (if the -time-passes option is enabled) or it leaves it
1737 // null.  It may be called multiple times.
1738 void TimingInfo::createTheTimeInfo() {
1739   if (!TimePassesIsEnabled || TheTimeInfo) return;
1740
1741   // Constructed the first time this is called, iff -time-passes is enabled.
1742   // This guarantees that the object will be constructed before static globals,
1743   // thus it will be destroyed before them.
1744   static ManagedStatic<TimingInfo> TTI;
1745   TheTimeInfo = &*TTI;
1746 }
1747
1748 /// If TimingInfo is enabled then start pass timer.
1749 Timer *llvm::getPassTimer(Pass *P) {
1750   if (TheTimeInfo)
1751     return TheTimeInfo->getPassTimer(P);
1752   return nullptr;
1753 }
1754
1755 //===----------------------------------------------------------------------===//
1756 // PMStack implementation
1757 //
1758
1759 // Pop Pass Manager from the stack and clear its analysis info.
1760 void PMStack::pop() {
1761
1762   PMDataManager *Top = this->top();
1763   Top->initializeAnalysisInfo();
1764
1765   S.pop_back();
1766 }
1767
1768 // Push PM on the stack and set its top level manager.
1769 void PMStack::push(PMDataManager *PM) {
1770   assert(PM && "Unable to push. Pass Manager expected");
1771   assert(PM->getDepth()==0 && "Pass Manager depth set too early");
1772
1773   if (!this->empty()) {
1774     assert(PM->getPassManagerType() > this->top()->getPassManagerType()
1775            && "pushing bad pass manager to PMStack");
1776     PMTopLevelManager *TPM = this->top()->getTopLevelManager();
1777
1778     assert(TPM && "Unable to find top level manager");
1779     TPM->addIndirectPassManager(PM);
1780     PM->setTopLevelManager(TPM);
1781     PM->setDepth(this->top()->getDepth()+1);
1782   } else {
1783     assert((PM->getPassManagerType() == PMT_ModulePassManager
1784            || PM->getPassManagerType() == PMT_FunctionPassManager)
1785            && "pushing bad pass manager to PMStack");
1786     PM->setDepth(1);
1787   }
1788
1789   S.push_back(PM);
1790 }
1791
1792 // Dump content of the pass manager stack.
1793 LLVM_DUMP_METHOD void PMStack::dump() const {
1794   for (PMDataManager *Manager : S)
1795     dbgs() << Manager->getAsPass()->getPassName() << ' ';
1796
1797   if (!S.empty())
1798     dbgs() << '\n';
1799 }
1800
1801 /// Find appropriate Module Pass Manager in the PM Stack and
1802 /// add self into that manager.
1803 void ModulePass::assignPassManager(PMStack &PMS,
1804                                    PassManagerType PreferredType) {
1805   // Find Module Pass Manager
1806   while (!PMS.empty()) {
1807     PassManagerType TopPMType = PMS.top()->getPassManagerType();
1808     if (TopPMType == PreferredType)
1809       break; // We found desired pass manager
1810     else if (TopPMType > PMT_ModulePassManager)
1811       PMS.pop();    // Pop children pass managers
1812     else
1813       break;
1814   }
1815   assert(!PMS.empty() && "Unable to find appropriate Pass Manager");
1816   PMS.top()->add(this);
1817 }
1818
1819 /// Find appropriate Function Pass Manager or Call Graph Pass Manager
1820 /// in the PM Stack and add self into that manager.
1821 void FunctionPass::assignPassManager(PMStack &PMS,
1822                                      PassManagerType PreferredType) {
1823
1824   // Find Function Pass Manager
1825   while (!PMS.empty()) {
1826     if (PMS.top()->getPassManagerType() > PMT_FunctionPassManager)
1827       PMS.pop();
1828     else
1829       break;
1830   }
1831
1832   // Create new Function Pass Manager if needed.
1833   FPPassManager *FPP;
1834   if (PMS.top()->getPassManagerType() == PMT_FunctionPassManager) {
1835     FPP = (FPPassManager *)PMS.top();
1836   } else {
1837     assert(!PMS.empty() && "Unable to create Function Pass Manager");
1838     PMDataManager *PMD = PMS.top();
1839
1840     // [1] Create new Function Pass Manager
1841     FPP = new FPPassManager();
1842     FPP->populateInheritedAnalysis(PMS);
1843
1844     // [2] Set up new manager's top level manager
1845     PMTopLevelManager *TPM = PMD->getTopLevelManager();
1846     TPM->addIndirectPassManager(FPP);
1847
1848     // [3] Assign manager to manage this new manager. This may create
1849     // and push new managers into PMS
1850     FPP->assignPassManager(PMS, PMD->getPassManagerType());
1851
1852     // [4] Push new manager into PMS
1853     PMS.push(FPP);
1854   }
1855
1856   // Assign FPP as the manager of this pass.
1857   FPP->add(this);
1858 }
1859
1860 /// Find appropriate Basic Pass Manager or Call Graph Pass Manager
1861 /// in the PM Stack and add self into that manager.
1862 void BasicBlockPass::assignPassManager(PMStack &PMS,
1863                                        PassManagerType PreferredType) {
1864   BBPassManager *BBP;
1865
1866   // Basic Pass Manager is a leaf pass manager. It does not handle
1867   // any other pass manager.
1868   if (!PMS.empty() &&
1869       PMS.top()->getPassManagerType() == PMT_BasicBlockPassManager) {
1870     BBP = (BBPassManager *)PMS.top();
1871   } else {
1872     // If leaf manager is not Basic Block Pass manager then create new
1873     // basic Block Pass manager.
1874     assert(!PMS.empty() && "Unable to create BasicBlock Pass Manager");
1875     PMDataManager *PMD = PMS.top();
1876
1877     // [1] Create new Basic Block Manager
1878     BBP = new BBPassManager();
1879
1880     // [2] Set up new manager's top level manager
1881     // Basic Block Pass Manager does not live by itself
1882     PMTopLevelManager *TPM = PMD->getTopLevelManager();
1883     TPM->addIndirectPassManager(BBP);
1884
1885     // [3] Assign manager to manage this new manager. This may create
1886     // and push new managers into PMS
1887     BBP->assignPassManager(PMS, PreferredType);
1888
1889     // [4] Push new manager into PMS
1890     PMS.push(BBP);
1891   }
1892
1893   // Assign BBP as the manager of this pass.
1894   BBP->add(this);
1895 }
1896
1897 PassManagerBase::~PassManagerBase() {}