1 //===- LegacyPassManagers.h - Legacy Pass Infrastructure --------*- 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_IR_LEGACYPASSMANAGERS_H
15 #define LLVM_IR_LEGACYPASSMANAGERS_H
16 
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SmallPtrSet.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/Pass.h"
22 #include <map>
23 #include <vector>
24 
25 //===----------------------------------------------------------------------===//
26 // Overview:
27 // The Pass Manager Infrastructure manages passes. It's responsibilities are:
28 //
29 //   o Manage optimization pass execution order
30 //   o Make required Analysis information available before pass P is run
31 //   o Release memory occupied by dead passes
32 //   o If Analysis information is dirtied by a pass then regenerate Analysis
33 //     information before it is consumed by another pass.
34 //
35 // Pass Manager Infrastructure uses multiple pass managers.  They are
36 // PassManager, FunctionPassManager, MPPassManager, FPPassManager, BBPassManager.
37 // This class hierarchy uses multiple inheritance but pass managers do not
38 // derive from another pass manager.
39 //
40 // PassManager and FunctionPassManager are two top-level pass manager that
41 // represents the external interface of this entire pass manager infrastucture.
42 //
43 // Important classes :
44 //
45 // [o] class PMTopLevelManager;
46 //
47 // Two top level managers, PassManager and FunctionPassManager, derive from
48 // PMTopLevelManager. PMTopLevelManager manages information used by top level
49 // managers such as last user info.
50 //
51 // [o] class PMDataManager;
52 //
53 // PMDataManager manages information, e.g. list of available analysis info,
54 // used by a pass manager to manage execution order of passes. It also provides
55 // a place to implement common pass manager APIs. All pass managers derive from
56 // PMDataManager.
57 //
58 // [o] class BBPassManager : public FunctionPass, public PMDataManager;
59 //
60 // BBPassManager manages BasicBlockPasses.
61 //
62 // [o] class FunctionPassManager;
63 //
64 // This is a external interface used to manage FunctionPasses. This
65 // interface relies on FunctionPassManagerImpl to do all the tasks.
66 //
67 // [o] class FunctionPassManagerImpl : public ModulePass, PMDataManager,
68 //                                     public PMTopLevelManager;
69 //
70 // FunctionPassManagerImpl is a top level manager. It manages FPPassManagers
71 //
72 // [o] class FPPassManager : public ModulePass, public PMDataManager;
73 //
74 // FPPassManager manages FunctionPasses and BBPassManagers
75 //
76 // [o] class MPPassManager : public Pass, public PMDataManager;
77 //
78 // MPPassManager manages ModulePasses and FPPassManagers
79 //
80 // [o] class PassManager;
81 //
82 // This is a external interface used by various tools to manages passes. It
83 // relies on PassManagerImpl to do all the tasks.
84 //
85 // [o] class PassManagerImpl : public Pass, public PMDataManager,
86 //                             public PMTopLevelManager
87 //
88 // PassManagerImpl is a top level pass manager responsible for managing
89 // MPPassManagers.
90 //===----------------------------------------------------------------------===//
91 
92 #include "llvm/Support/PrettyStackTrace.h"
93 
94 namespace llvm {
95   class Module;
96   class Pass;
97   class StringRef;
98   class Value;
99   class Timer;
100   class PMDataManager;
101 
102 // enums for debugging strings
103 enum PassDebuggingString {
104   EXECUTION_MSG, // "Executing Pass '" + PassName
105   MODIFICATION_MSG, // "Made Modification '" + PassName
106   FREEING_MSG, // " Freeing Pass '" + PassName
107   ON_BASICBLOCK_MSG, // "' on BasicBlock '" + InstructionName + "'...\n"
108   ON_FUNCTION_MSG, // "' on Function '" + FunctionName + "'...\n"
109   ON_MODULE_MSG, // "' on Module '" + ModuleName + "'...\n"
110   ON_REGION_MSG, // "' on Region '" + Msg + "'...\n'"
111   ON_LOOP_MSG, // "' on Loop '" + Msg + "'...\n'"
112   ON_CG_MSG // "' on Call Graph Nodes '" + Msg + "'...\n'"
113 };
114 
115 /// PassManagerPrettyStackEntry - This is used to print informative information
116 /// about what pass is running when/if a stack trace is generated.
117 class PassManagerPrettyStackEntry : public PrettyStackTraceEntry {
118   Pass *P;
119   Value *V;
120   Module *M;
121 public:
PassManagerPrettyStackEntry(Pass * p)122   explicit PassManagerPrettyStackEntry(Pass *p)
123     : P(p), V(nullptr), M(nullptr) {}  // When P is releaseMemory'd.
PassManagerPrettyStackEntry(Pass * p,Value & v)124   PassManagerPrettyStackEntry(Pass *p, Value &v)
125     : P(p), V(&v), M(nullptr) {} // When P is run on V
PassManagerPrettyStackEntry(Pass * p,Module & m)126   PassManagerPrettyStackEntry(Pass *p, Module &m)
127     : P(p), V(nullptr), M(&m) {} // When P is run on M
128 
129   /// print - Emit information about this stack frame to OS.
130   void print(raw_ostream &OS) const override;
131 };
132 
133 
134 //===----------------------------------------------------------------------===//
135 // PMStack
136 //
137 /// PMStack - This class implements a stack data structure of PMDataManager
138 /// pointers.
139 ///
140 /// Top level pass managers (see PassManager.cpp) maintain active Pass Managers
141 /// using PMStack. Each Pass implements assignPassManager() to connect itself
142 /// with appropriate manager. assignPassManager() walks PMStack to find
143 /// suitable manager.
144 class PMStack {
145 public:
146   typedef std::vector<PMDataManager *>::const_reverse_iterator iterator;
begin()147   iterator begin() const { return S.rbegin(); }
end()148   iterator end() const { return S.rend(); }
149 
150   void pop();
top()151   PMDataManager *top() const { return S.back(); }
152   void push(PMDataManager *PM);
empty()153   bool empty() const { return S.empty(); }
154 
155   void dump() const;
156 
157 private:
158   std::vector<PMDataManager *> S;
159 };
160 
161 
162 //===----------------------------------------------------------------------===//
163 // PMTopLevelManager
164 //
165 /// PMTopLevelManager manages LastUser info and collects common APIs used by
166 /// top level pass managers.
167 class PMTopLevelManager {
168 protected:
169   explicit PMTopLevelManager(PMDataManager *PMDM);
170 
getNumContainedManagers()171   unsigned getNumContainedManagers() const {
172     return (unsigned)PassManagers.size();
173   }
174 
175   void initializeAllAnalysisInfo();
176 
177 private:
178   virtual PMDataManager *getAsPMDataManager() = 0;
179   virtual PassManagerType getTopLevelPassManagerType() = 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(ArrayRef<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   /// Retrieve the PassInfo for an analysis.
199   const PassInfo *findAnalysisPassInfo(AnalysisID AID) const;
200 
201   /// Find analysis usage information for the pass P.
202   AnalysisUsage *findAnalysisUsage(Pass *P);
203 
204   virtual ~PMTopLevelManager();
205 
206   /// Add immutable pass and initialize it.
addImmutablePass(ImmutablePass * P)207   inline void addImmutablePass(ImmutablePass *P) {
208     P->initializePass();
209     ImmutablePasses.push_back(P);
210   }
211 
getImmutablePasses()212   inline SmallVectorImpl<ImmutablePass *>& getImmutablePasses() {
213     return ImmutablePasses;
214   }
215 
addPassManager(PMDataManager * Manager)216   void addPassManager(PMDataManager *Manager) {
217     PassManagers.push_back(Manager);
218   }
219 
220   // Add Manager into the list of managers that are not directly
221   // maintained by this top level pass manager
addIndirectPassManager(PMDataManager * Manager)222   inline void addIndirectPassManager(PMDataManager *Manager) {
223     IndirectPassManagers.push_back(Manager);
224   }
225 
226   // Print passes managed by this top level manager.
227   void dumpPasses() const;
228   void dumpArguments() const;
229 
230   // Active Pass Managers
231   PMStack activeStack;
232 
233 protected:
234 
235   /// Collection of pass managers
236   SmallVector<PMDataManager *, 8> PassManagers;
237 
238 private:
239 
240   /// Collection of pass managers that are not directly maintained
241   /// by this pass manager
242   SmallVector<PMDataManager *, 8> IndirectPassManagers;
243 
244   // Map to keep track of last user of the analysis pass.
245   // LastUser->second is the last user of Lastuser->first.
246   DenseMap<Pass *, Pass *> LastUser;
247 
248   // Map to keep track of passes that are last used by a pass.
249   // This inverse map is initialized at PM->run() based on
250   // LastUser map.
251   DenseMap<Pass *, SmallPtrSet<Pass *, 8> > InversedLastUser;
252 
253   /// Immutable passes are managed by top level manager.
254   SmallVector<ImmutablePass *, 16> ImmutablePasses;
255 
256   DenseMap<Pass *, AnalysisUsage *> AnUsageMap;
257 
258   /// Collection of PassInfo objects found via analysis IDs and in this top
259   /// level manager. This is used to memoize queries to the pass registry.
260   /// FIXME: This is an egregious hack because querying the pass registry is
261   /// either slow or racy.
262   mutable DenseMap<AnalysisID, const PassInfo *> AnalysisPassInfos;
263 };
264 
265 
266 
267 //===----------------------------------------------------------------------===//
268 // PMDataManager
269 
270 /// PMDataManager provides the common place to manage the analysis data
271 /// used by pass managers.
272 class PMDataManager {
273 public:
274 
PMDataManager()275   explicit PMDataManager() : TPM(nullptr), Depth(0) {
276     initializeAnalysisInfo();
277   }
278 
279   virtual ~PMDataManager();
280 
281   virtual Pass *getAsPass() = 0;
282 
283   /// Augment AvailableAnalysis by adding analysis made available by pass P.
284   void recordAvailableAnalysis(Pass *P);
285 
286   /// verifyPreservedAnalysis -- Verify analysis presreved by pass P.
287   void verifyPreservedAnalysis(Pass *P);
288 
289   /// Remove Analysis that is not preserved by the pass
290   void removeNotPreservedAnalysis(Pass *P);
291 
292   /// Remove dead passes used by P.
293   void removeDeadPasses(Pass *P, StringRef Msg,
294                         enum PassDebuggingString);
295 
296   /// Remove P.
297   void freePass(Pass *P, StringRef Msg,
298                 enum PassDebuggingString);
299 
300   /// Add pass P into the PassVector. Update
301   /// AvailableAnalysis appropriately if ProcessAnalysis is true.
302   void add(Pass *P, bool ProcessAnalysis = true);
303 
304   /// Add RequiredPass into list of lower level passes required by pass P.
305   /// RequiredPass is run on the fly by Pass Manager when P requests it
306   /// through getAnalysis interface.
307   virtual void addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass);
308 
309   virtual Pass *getOnTheFlyPass(Pass *P, AnalysisID PI, Function &F);
310 
311   /// Initialize available analysis information.
initializeAnalysisInfo()312   void initializeAnalysisInfo() {
313     AvailableAnalysis.clear();
314     for (unsigned i = 0; i < PMT_Last; ++i)
315       InheritedAnalysis[i] = nullptr;
316   }
317 
318   // Return true if P preserves high level analysis used by other
319   // passes that are managed by this manager.
320   bool preserveHigherLevelAnalysis(Pass *P);
321 
322 
323   /// Populate RequiredPasses with analysis pass that are required by
324   /// pass P and are available. Populate ReqPassNotAvailable with analysis
325   /// pass that are required by pass P but are not available.
326   void collectRequiredAnalysis(SmallVectorImpl<Pass *> &RequiredPasses,
327                                SmallVectorImpl<AnalysisID> &ReqPassNotAvailable,
328                                Pass *P);
329 
330   /// All Required analyses should be available to the pass as it runs!  Here
331   /// we fill in the AnalysisImpls member of the pass so that it can
332   /// successfully use the getAnalysis() method to retrieve the
333   /// implementations it needs.
334   void initializeAnalysisImpl(Pass *P);
335 
336   /// Find the pass that implements Analysis AID. If desired pass is not found
337   /// then return NULL.
338   Pass *findAnalysisPass(AnalysisID AID, bool Direction);
339 
340   // Access toplevel manager
getTopLevelManager()341   PMTopLevelManager *getTopLevelManager() { return TPM; }
setTopLevelManager(PMTopLevelManager * T)342   void setTopLevelManager(PMTopLevelManager *T) { TPM = T; }
343 
getDepth()344   unsigned getDepth() const { return Depth; }
setDepth(unsigned newDepth)345   void setDepth(unsigned newDepth) { Depth = newDepth; }
346 
347   // Print routines used by debug-pass
348   void dumpLastUses(Pass *P, unsigned Offset) const;
349   void dumpPassArguments() const;
350   void dumpPassInfo(Pass *P, enum PassDebuggingString S1,
351                     enum PassDebuggingString S2, StringRef Msg);
352   void dumpRequiredSet(const Pass *P) const;
353   void dumpPreservedSet(const Pass *P) const;
354 
getNumContainedPasses()355   unsigned getNumContainedPasses() const {
356     return (unsigned)PassVector.size();
357   }
358 
getPassManagerType()359   virtual PassManagerType getPassManagerType() const {
360     assert ( 0 && "Invalid use of getPassManagerType");
361     return PMT_Unknown;
362   }
363 
getAvailableAnalysis()364   DenseMap<AnalysisID, Pass*> *getAvailableAnalysis() {
365     return &AvailableAnalysis;
366   }
367 
368   // Collect AvailableAnalysis from all the active Pass Managers.
populateInheritedAnalysis(PMStack & PMS)369   void populateInheritedAnalysis(PMStack &PMS) {
370     unsigned Index = 0;
371     for (PMStack::iterator I = PMS.begin(), E = PMS.end();
372          I != E; ++I)
373       InheritedAnalysis[Index++] = (*I)->getAvailableAnalysis();
374   }
375 
376 protected:
377 
378   // Top level manager.
379   PMTopLevelManager *TPM;
380 
381   // Collection of pass that are managed by this manager
382   SmallVector<Pass *, 16> PassVector;
383 
384   // Collection of Analysis provided by Parent pass manager and
385   // used by current pass manager. At at time there can not be more
386   // then PMT_Last active pass mangers.
387   DenseMap<AnalysisID, Pass *> *InheritedAnalysis[PMT_Last];
388 
389   /// isPassDebuggingExecutionsOrMore - Return true if -debug-pass=Executions
390   /// or higher is specified.
391   bool isPassDebuggingExecutionsOrMore() const;
392 
393 private:
394   void dumpAnalysisUsage(StringRef Msg, const Pass *P,
395                          const AnalysisUsage::VectorType &Set) const;
396 
397   // Set of available Analysis. This information is used while scheduling
398   // pass. If a pass requires an analysis which is not available then
399   // the required analysis pass is scheduled to run before the pass itself is
400   // scheduled to run.
401   DenseMap<AnalysisID, Pass*> AvailableAnalysis;
402 
403   // Collection of higher level analysis used by the pass managed by
404   // this manager.
405   SmallVector<Pass *, 16> HigherLevelAnalysis;
406 
407   unsigned Depth;
408 };
409 
410 //===----------------------------------------------------------------------===//
411 // FPPassManager
412 //
413 /// FPPassManager manages BBPassManagers and FunctionPasses.
414 /// It batches all function passes and basic block pass managers together and
415 /// sequence them to process one function at a time before processing next
416 /// function.
417 class FPPassManager : public ModulePass, public PMDataManager {
418 public:
419   static char ID;
FPPassManager()420   explicit FPPassManager()
421   : ModulePass(ID), PMDataManager() { }
422 
423   /// run - Execute all of the passes scheduled for execution.  Keep track of
424   /// whether any of the passes modifies the module, and if so, return true.
425   bool runOnFunction(Function &F);
426   bool runOnModule(Module &M) override;
427 
428   /// cleanup - After running all passes, clean up pass manager cache.
429   void cleanup();
430 
431   /// doInitialization - Overrides ModulePass doInitialization for global
432   /// initialization tasks
433   ///
434   using ModulePass::doInitialization;
435 
436   /// doInitialization - Run all of the initializers for the function passes.
437   ///
438   bool doInitialization(Module &M) override;
439 
440   /// doFinalization - Overrides ModulePass doFinalization for global
441   /// finalization tasks
442   ///
443   using ModulePass::doFinalization;
444 
445   /// doFinalization - Run all of the finalizers for the function passes.
446   ///
447   bool doFinalization(Module &M) override;
448 
getAsPMDataManager()449   PMDataManager *getAsPMDataManager() override { return this; }
getAsPass()450   Pass *getAsPass() override { return this; }
451 
452   /// Pass Manager itself does not invalidate any analysis info.
getAnalysisUsage(AnalysisUsage & Info)453   void getAnalysisUsage(AnalysisUsage &Info) const override {
454     Info.setPreservesAll();
455   }
456 
457   // Print passes managed by this manager
458   void dumpPassStructure(unsigned Offset) override;
459 
getPassName()460   const char *getPassName() const override {
461     return "Function Pass Manager";
462   }
463 
getContainedPass(unsigned N)464   FunctionPass *getContainedPass(unsigned N) {
465     assert ( N < PassVector.size() && "Pass number out of range!");
466     FunctionPass *FP = static_cast<FunctionPass *>(PassVector[N]);
467     return FP;
468   }
469 
getPassManagerType()470   PassManagerType getPassManagerType() const override {
471     return PMT_FunctionPassManager;
472   }
473 };
474 
475 Timer *getPassTimer(Pass *);
476 
477 }
478 
479 #endif
480