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      1 //===- llvm/PassManagers.h - Pass Infrastructure classes  -------*- 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 // This file declares the LLVM Pass Manager infrastructure.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_PASSMANAGERS_H
     15 #define LLVM_PASSMANAGERS_H
     16 
     17 #include "llvm/Pass.h"
     18 #include "llvm/ADT/SmallVector.h"
     19 #include "llvm/ADT/SmallPtrSet.h"
     20 #include "llvm/ADT/DenseMap.h"
     21 #include <vector>
     22 #include <map>
     23 
     24 //===----------------------------------------------------------------------===//
     25 // Overview:
     26 // The Pass Manager Infrastructure manages passes. It's responsibilities are:
     27 //
     28 //   o Manage optimization pass execution order
     29 //   o Make required Analysis information available before pass P is run
     30 //   o Release memory occupied by dead passes
     31 //   o If Analysis information is dirtied by a pass then regenerate Analysis
     32 //     information before it is consumed by another pass.
     33 //
     34 // Pass Manager Infrastructure uses multiple pass managers.  They are
     35 // PassManager, FunctionPassManager, MPPassManager, FPPassManager, BBPassManager.
     36 // This class hierarchy uses multiple inheritance but pass managers do not
     37 // derive from another pass manager.
     38 //
     39 // PassManager and FunctionPassManager are two top-level pass manager that
     40 // represents the external interface of this entire pass manager infrastucture.
     41 //
     42 // Important classes :
     43 //
     44 // [o] class PMTopLevelManager;
     45 //
     46 // Two top level managers, PassManager and FunctionPassManager, derive from
     47 // PMTopLevelManager. PMTopLevelManager manages information used by top level
     48 // managers such as last user info.
     49 //
     50 // [o] class PMDataManager;
     51 //
     52 // PMDataManager manages information, e.g. list of available analysis info,
     53 // used by a pass manager to manage execution order of passes. It also provides
     54 // a place to implement common pass manager APIs. All pass managers derive from
     55 // PMDataManager.
     56 //
     57 // [o] class BBPassManager : public FunctionPass, public PMDataManager;
     58 //
     59 // BBPassManager manages BasicBlockPasses.
     60 //
     61 // [o] class FunctionPassManager;
     62 //
     63 // This is a external interface used by JIT to manage FunctionPasses. This
     64 // interface relies on FunctionPassManagerImpl to do all the tasks.
     65 //
     66 // [o] class FunctionPassManagerImpl : public ModulePass, PMDataManager,
     67 //                                     public PMTopLevelManager;
     68 //
     69 // FunctionPassManagerImpl is a top level manager. It manages FPPassManagers
     70 //
     71 // [o] class FPPassManager : public ModulePass, public PMDataManager;
     72 //
     73 // FPPassManager manages FunctionPasses and BBPassManagers
     74 //
     75 // [o] class MPPassManager : public Pass, public PMDataManager;
     76 //
     77 // MPPassManager manages ModulePasses and FPPassManagers
     78 //
     79 // [o] class PassManager;
     80 //
     81 // This is a external interface used by various tools to manages passes. It
     82 // relies on PassManagerImpl to do all the tasks.
     83 //
     84 // [o] class PassManagerImpl : public Pass, public PMDataManager,
     85 //                             public PMDTopLevelManager
     86 //
     87 // PassManagerImpl is a top level pass manager responsible for managing
     88 // MPPassManagers.
     89 //===----------------------------------------------------------------------===//
     90 
     91 #include "llvm/Support/PrettyStackTrace.h"
     92 
     93 namespace llvm {
     94   class Module;
     95   class Pass;
     96   class StringRef;
     97   class Value;
     98   class Timer;
     99   class PMDataManager;
    100 
    101 // enums for debugging strings
    102 enum PassDebuggingString {
    103   EXECUTION_MSG, // "Executing Pass '"
    104   MODIFICATION_MSG, // "' Made Modification '"
    105   FREEING_MSG, // " Freeing Pass '"
    106   ON_BASICBLOCK_MSG, // "'  on BasicBlock '" + PassName + "'...\n"
    107   ON_FUNCTION_MSG, // "' on Function '" + FunctionName + "'...\n"
    108   ON_MODULE_MSG, // "' on Module '" + ModuleName + "'...\n"
    109   ON_REGION_MSG, // " 'on Region ...\n'"
    110   ON_LOOP_MSG, // " 'on Loop ...\n'"
    111   ON_CG_MSG // "' on Call Graph ...\n'"
    112 };
    113 
    114 /// PassManagerPrettyStackEntry - This is used to print informative information
    115 /// about what pass is running when/if a stack trace is generated.
    116 class PassManagerPrettyStackEntry : public PrettyStackTraceEntry {
    117   Pass *P;
    118   Value *V;
    119   Module *M;
    120 public:
    121   explicit PassManagerPrettyStackEntry(Pass *p)
    122     : P(p), V(0), M(0) {}  // When P is releaseMemory'd.
    123   PassManagerPrettyStackEntry(Pass *p, Value &v)
    124     : P(p), V(&v), M(0) {} // When P is run on V
    125   PassManagerPrettyStackEntry(Pass *p, Module &m)
    126     : P(p), V(0), M(&m) {} // When P is run on M
    127 
    128   /// print - Emit information about this stack frame to OS.
    129   virtual void print(raw_ostream &OS) const;
    130 };
    131 
    132 
    133 //===----------------------------------------------------------------------===//
    134 // PMStack
    135 //
    136 /// PMStack - This class implements a stack data structure of PMDataManager
    137 /// pointers.
    138 ///
    139 /// Top level pass managers (see PassManager.cpp) maintain active Pass Managers
    140 /// using PMStack. Each Pass implements assignPassManager() to connect itself
    141 /// with appropriate manager. assignPassManager() walks PMStack to find
    142 /// suitable manager.
    143 class PMStack {
    144 public:
    145   typedef std::vector<PMDataManager *>::const_reverse_iterator iterator;
    146   iterator begin() const { return S.rbegin(); }
    147   iterator end() const { return S.rend(); }
    148 
    149   void pop();
    150   PMDataManager *top() const { return S.back(); }
    151   void push(PMDataManager *PM);
    152   bool empty() const { return S.empty(); }
    153 
    154   void dump() const;
    155 
    156 private:
    157   std::vector<PMDataManager *> S;
    158 };
    159 
    160 
    161 //===----------------------------------------------------------------------===//
    162 // PMTopLevelManager
    163 //
    164 /// PMTopLevelManager manages LastUser info and collects common APIs used by
    165 /// top level pass managers.
    166 class PMTopLevelManager {
    167 protected:
    168   explicit PMTopLevelManager(PMDataManager *PMDM);
    169 
    170   virtual unsigned getNumContainedManagers() const {
    171     return (unsigned)PassManagers.size();
    172   }
    173 
    174   void initializeAllAnalysisInfo();
    175 
    176 private:
    177   /// This is implemented by top level pass manager and used by
    178   /// schedulePass() to add analysis info passes that are not available.
    179   virtual void addTopLevelPass(Pass  *P) = 0;
    180 
    181 public:
    182   /// Schedule pass P for execution. Make sure that passes required by
    183   /// P are run before P is run. Update analysis info maintained by
    184   /// the manager. Remove dead passes. This is a recursive function.
    185   void schedulePass(Pass *P);
    186 
    187   /// Set pass P as the last user of the given analysis passes.
    188   void setLastUser(const SmallVectorImpl<Pass *> &AnalysisPasses, Pass *P);
    189 
    190   /// Collect passes whose last user is P
    191   void collectLastUses(SmallVectorImpl<Pass *> &LastUses, Pass *P);
    192 
    193   /// Find the pass that implements Analysis AID. Search immutable
    194   /// passes and all pass managers. If desired pass is not found
    195   /// then return NULL.
    196   Pass *findAnalysisPass(AnalysisID AID);
    197 
    198   /// Find analysis usage information for the pass P.
    199   AnalysisUsage *findAnalysisUsage(Pass *P);
    200 
    201   virtual ~PMTopLevelManager();
    202 
    203   /// Add immutable pass and initialize it.
    204   inline void addImmutablePass(ImmutablePass *P) {
    205     P->initializePass();
    206     ImmutablePasses.push_back(P);
    207   }
    208 
    209   inline SmallVectorImpl<ImmutablePass *>& getImmutablePasses() {
    210     return ImmutablePasses;
    211   }
    212 
    213   void addPassManager(PMDataManager *Manager) {
    214     PassManagers.push_back(Manager);
    215   }
    216 
    217   // Add Manager into the list of managers that are not directly
    218   // maintained by this top level pass manager
    219   inline void addIndirectPassManager(PMDataManager *Manager) {
    220     IndirectPassManagers.push_back(Manager);
    221   }
    222 
    223   // Print passes managed by this top level manager.
    224   void dumpPasses() const;
    225   void dumpArguments() const;
    226 
    227   // Active Pass Managers
    228   PMStack activeStack;
    229 
    230 protected:
    231 
    232   /// Collection of pass managers
    233   SmallVector<PMDataManager *, 8> PassManagers;
    234 
    235 private:
    236 
    237   /// Collection of pass managers that are not directly maintained
    238   /// by this pass manager
    239   SmallVector<PMDataManager *, 8> IndirectPassManagers;
    240 
    241   // Map to keep track of last user of the analysis pass.
    242   // LastUser->second is the last user of Lastuser->first.
    243   DenseMap<Pass *, Pass *> LastUser;
    244 
    245   // Map to keep track of passes that are last used by a pass.
    246   // This inverse map is initialized at PM->run() based on
    247   // LastUser map.
    248   DenseMap<Pass *, SmallPtrSet<Pass *, 8> > InversedLastUser;
    249 
    250   /// Immutable passes are managed by top level manager.
    251   SmallVector<ImmutablePass *, 8> ImmutablePasses;
    252 
    253   DenseMap<Pass *, AnalysisUsage *> AnUsageMap;
    254 };
    255 
    256 
    257 
    258 //===----------------------------------------------------------------------===//
    259 // PMDataManager
    260 
    261 /// PMDataManager provides the common place to manage the analysis data
    262 /// used by pass managers.
    263 class PMDataManager {
    264 public:
    265 
    266   explicit PMDataManager() : TPM(NULL), Depth(0) {
    267     initializeAnalysisInfo();
    268   }
    269 
    270   virtual ~PMDataManager();
    271 
    272   virtual Pass *getAsPass() = 0;
    273 
    274   /// Augment AvailableAnalysis by adding analysis made available by pass P.
    275   void recordAvailableAnalysis(Pass *P);
    276 
    277   /// verifyPreservedAnalysis -- Verify analysis presreved by pass P.
    278   void verifyPreservedAnalysis(Pass *P);
    279 
    280   /// Remove Analysis that is not preserved by the pass
    281   void removeNotPreservedAnalysis(Pass *P);
    282 
    283   /// Remove dead passes used by P.
    284   void removeDeadPasses(Pass *P, StringRef Msg,
    285                         enum PassDebuggingString);
    286 
    287   /// Remove P.
    288   void freePass(Pass *P, StringRef Msg,
    289                 enum PassDebuggingString);
    290 
    291   /// Add pass P into the PassVector. Update
    292   /// AvailableAnalysis appropriately if ProcessAnalysis is true.
    293   void add(Pass *P, bool ProcessAnalysis = true);
    294 
    295   /// Add RequiredPass into list of lower level passes required by pass P.
    296   /// RequiredPass is run on the fly by Pass Manager when P requests it
    297   /// through getAnalysis interface.
    298   virtual void addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass);
    299 
    300   virtual Pass *getOnTheFlyPass(Pass *P, AnalysisID PI, Function &F);
    301 
    302   /// Initialize available analysis information.
    303   void initializeAnalysisInfo() {
    304     AvailableAnalysis.clear();
    305     for (unsigned i = 0; i < PMT_Last; ++i)
    306       InheritedAnalysis[i] = NULL;
    307   }
    308 
    309   // Return true if P preserves high level analysis used by other
    310   // passes that are managed by this manager.
    311   bool preserveHigherLevelAnalysis(Pass *P);
    312 
    313 
    314   /// Populate RequiredPasses with analysis pass that are required by
    315   /// pass P and are available. Populate ReqPassNotAvailable with analysis
    316   /// pass that are required by pass P but are not available.
    317   void collectRequiredAnalysis(SmallVectorImpl<Pass *> &RequiredPasses,
    318                                SmallVectorImpl<AnalysisID> &ReqPassNotAvailable,
    319                                Pass *P);
    320 
    321   /// All Required analyses should be available to the pass as it runs!  Here
    322   /// we fill in the AnalysisImpls member of the pass so that it can
    323   /// successfully use the getAnalysis() method to retrieve the
    324   /// implementations it needs.
    325   void initializeAnalysisImpl(Pass *P);
    326 
    327   /// Find the pass that implements Analysis AID. If desired pass is not found
    328   /// then return NULL.
    329   Pass *findAnalysisPass(AnalysisID AID, bool Direction);
    330 
    331   // Access toplevel manager
    332   PMTopLevelManager *getTopLevelManager() { return TPM; }
    333   void setTopLevelManager(PMTopLevelManager *T) { TPM = T; }
    334 
    335   unsigned getDepth() const { return Depth; }
    336   void setDepth(unsigned newDepth) { Depth = newDepth; }
    337 
    338   // Print routines used by debug-pass
    339   void dumpLastUses(Pass *P, unsigned Offset) const;
    340   void dumpPassArguments() const;
    341   void dumpPassInfo(Pass *P, enum PassDebuggingString S1,
    342                     enum PassDebuggingString S2, StringRef Msg);
    343   void dumpRequiredSet(const Pass *P) const;
    344   void dumpPreservedSet(const Pass *P) const;
    345 
    346   virtual unsigned getNumContainedPasses() const {
    347     return (unsigned)PassVector.size();
    348   }
    349 
    350   virtual PassManagerType getPassManagerType() const {
    351     assert ( 0 && "Invalid use of getPassManagerType");
    352     return PMT_Unknown;
    353   }
    354 
    355   std::map<AnalysisID, Pass*> *getAvailableAnalysis() {
    356     return &AvailableAnalysis;
    357   }
    358 
    359   // Collect AvailableAnalysis from all the active Pass Managers.
    360   void populateInheritedAnalysis(PMStack &PMS) {
    361     unsigned Index = 0;
    362     for (PMStack::iterator I = PMS.begin(), E = PMS.end();
    363          I != E; ++I)
    364       InheritedAnalysis[Index++] = (*I)->getAvailableAnalysis();
    365   }
    366 
    367 protected:
    368 
    369   // Top level manager.
    370   PMTopLevelManager *TPM;
    371 
    372   // Collection of pass that are managed by this manager
    373   SmallVector<Pass *, 16> PassVector;
    374 
    375   // Collection of Analysis provided by Parent pass manager and
    376   // used by current pass manager. At at time there can not be more
    377   // then PMT_Last active pass mangers.
    378   std::map<AnalysisID, Pass *> *InheritedAnalysis[PMT_Last];
    379 
    380 
    381   /// isPassDebuggingExecutionsOrMore - Return true if -debug-pass=Executions
    382   /// or higher is specified.
    383   bool isPassDebuggingExecutionsOrMore() const;
    384 
    385 private:
    386   void dumpAnalysisUsage(StringRef Msg, const Pass *P,
    387                          const AnalysisUsage::VectorType &Set) const;
    388 
    389   // Set of available Analysis. This information is used while scheduling
    390   // pass. If a pass requires an analysis which is not available then
    391   // the required analysis pass is scheduled to run before the pass itself is
    392   // scheduled to run.
    393   std::map<AnalysisID, Pass*> AvailableAnalysis;
    394 
    395   // Collection of higher level analysis used by the pass managed by
    396   // this manager.
    397   SmallVector<Pass *, 8> HigherLevelAnalysis;
    398 
    399   unsigned Depth;
    400 };
    401 
    402 //===----------------------------------------------------------------------===//
    403 // FPPassManager
    404 //
    405 /// FPPassManager manages BBPassManagers and FunctionPasses.
    406 /// It batches all function passes and basic block pass managers together and
    407 /// sequence them to process one function at a time before processing next
    408 /// function.
    409 class FPPassManager : public ModulePass, public PMDataManager {
    410 public:
    411   static char ID;
    412   explicit FPPassManager()
    413   : ModulePass(ID), PMDataManager() { }
    414 
    415   /// run - Execute all of the passes scheduled for execution.  Keep track of
    416   /// whether any of the passes modifies the module, and if so, return true.
    417   bool runOnFunction(Function &F);
    418   bool runOnModule(Module &M);
    419 
    420   /// cleanup - After running all passes, clean up pass manager cache.
    421   void cleanup();
    422 
    423   /// doInitialization - Run all of the initializers for the function passes.
    424   ///
    425   bool doInitialization(Module &M);
    426 
    427   /// doFinalization - Run all of the finalizers for the function passes.
    428   ///
    429   bool doFinalization(Module &M);
    430 
    431   virtual PMDataManager *getAsPMDataManager() { return this; }
    432   virtual Pass *getAsPass() { return this; }
    433 
    434   /// Pass Manager itself does not invalidate any analysis info.
    435   void getAnalysisUsage(AnalysisUsage &Info) const {
    436     Info.setPreservesAll();
    437   }
    438 
    439   // Print passes managed by this manager
    440   void dumpPassStructure(unsigned Offset);
    441 
    442   virtual const char *getPassName() const {
    443     return "Function Pass Manager";
    444   }
    445 
    446   FunctionPass *getContainedPass(unsigned N) {
    447     assert ( N < PassVector.size() && "Pass number out of range!");
    448     FunctionPass *FP = static_cast<FunctionPass *>(PassVector[N]);
    449     return FP;
    450   }
    451 
    452   virtual PassManagerType getPassManagerType() const {
    453     return PMT_FunctionPassManager;
    454   }
    455 };
    456 
    457 Timer *getPassTimer(Pass *);
    458 
    459 }
    460 
    461 #endif
    462