xref: /freebsd/contrib/llvm-project/llvm/include/llvm/IR/LegacyPassManagers.h (revision 6966ac055c3b7a39266fb982493330df7a097997)
1 //===- LegacyPassManagers.h - Legacy Pass Infrastructure --------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file declares the LLVM Pass Manager infrastructure.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_IR_LEGACYPASSMANAGERS_H
14 #define LLVM_IR_LEGACYPASSMANAGERS_H
15 
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/FoldingSet.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/Pass.h"
21 #include <vector>
22 
23 //===----------------------------------------------------------------------===//
24 // Overview:
25 // The Pass Manager Infrastructure manages passes. It's responsibilities are:
26 //
27 //   o Manage optimization pass execution order
28 //   o Make required Analysis information available before pass P is run
29 //   o Release memory occupied by dead passes
30 //   o If Analysis information is dirtied by a pass then regenerate Analysis
31 //     information before it is consumed by another pass.
32 //
33 // Pass Manager Infrastructure uses multiple pass managers.  They are
34 // PassManager, FunctionPassManager, MPPassManager, FPPassManager, BBPassManager.
35 // This class hierarchy uses multiple inheritance but pass managers do not
36 // derive from another pass manager.
37 //
38 // PassManager and FunctionPassManager are two top-level pass manager that
39 // represents the external interface of this entire pass manager infrastucture.
40 //
41 // Important classes :
42 //
43 // [o] class PMTopLevelManager;
44 //
45 // Two top level managers, PassManager and FunctionPassManager, derive from
46 // PMTopLevelManager. PMTopLevelManager manages information used by top level
47 // managers such as last user info.
48 //
49 // [o] class PMDataManager;
50 //
51 // PMDataManager manages information, e.g. list of available analysis info,
52 // used by a pass manager to manage execution order of passes. It also provides
53 // a place to implement common pass manager APIs. All pass managers derive from
54 // PMDataManager.
55 //
56 // [o] class BBPassManager : public FunctionPass, public PMDataManager;
57 //
58 // BBPassManager manages BasicBlockPasses.
59 //
60 // [o] class FunctionPassManager;
61 //
62 // This is a external interface used to manage FunctionPasses. This
63 // interface relies on FunctionPassManagerImpl to do all the tasks.
64 //
65 // [o] class FunctionPassManagerImpl : public ModulePass, PMDataManager,
66 //                                     public PMTopLevelManager;
67 //
68 // FunctionPassManagerImpl is a top level manager. It manages FPPassManagers
69 //
70 // [o] class FPPassManager : public ModulePass, public PMDataManager;
71 //
72 // FPPassManager manages FunctionPasses and BBPassManagers
73 //
74 // [o] class MPPassManager : public Pass, public PMDataManager;
75 //
76 // MPPassManager manages ModulePasses and FPPassManagers
77 //
78 // [o] class PassManager;
79 //
80 // This is a external interface used by various tools to manages passes. It
81 // relies on PassManagerImpl to do all the tasks.
82 //
83 // [o] class PassManagerImpl : public Pass, public PMDataManager,
84 //                             public PMTopLevelManager
85 //
86 // PassManagerImpl is a top level pass manager responsible for managing
87 // MPPassManagers.
88 //===----------------------------------------------------------------------===//
89 
90 #include "llvm/Support/PrettyStackTrace.h"
91 
92 namespace llvm {
93 template <typename T> class ArrayRef;
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 '" + PassName
104   MODIFICATION_MSG, // "Made Modification '" + PassName
105   FREEING_MSG, // " Freeing Pass '" + PassName
106   ON_BASICBLOCK_MSG, // "' on BasicBlock '" + InstructionName + "'...\n"
107   ON_FUNCTION_MSG, // "' on Function '" + FunctionName + "'...\n"
108   ON_MODULE_MSG, // "' on Module '" + ModuleName + "'...\n"
109   ON_REGION_MSG, // "' on Region '" + Msg + "'...\n'"
110   ON_LOOP_MSG, // "' on Loop '" + Msg + "'...\n'"
111   ON_CG_MSG // "' on Call Graph Nodes '" + Msg + "'...\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 
121 public:
122   explicit PassManagerPrettyStackEntry(Pass *p)
123     : P(p), V(nullptr), M(nullptr) {}  // When P is releaseMemory'd.
124   PassManagerPrettyStackEntry(Pass *p, Value &v)
125     : P(p), V(&v), M(nullptr) {} // When P is run on V
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 // 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 // PMTopLevelManager
162 //
163 /// PMTopLevelManager manages LastUser info and collects common APIs used by
164 /// top level pass managers.
165 class PMTopLevelManager {
166 protected:
167   explicit PMTopLevelManager(PMDataManager *PMDM);
168 
169   unsigned getNumContainedManagers() const {
170     return (unsigned)PassManagers.size();
171   }
172 
173   void initializeAllAnalysisInfo();
174 
175 private:
176   virtual PMDataManager *getAsPMDataManager() = 0;
177   virtual PassManagerType getTopLevelPassManagerType() = 0;
178 
179 public:
180   /// Schedule pass P for execution. Make sure that passes required by
181   /// P are run before P is run. Update analysis info maintained by
182   /// the manager. Remove dead passes. This is a recursive function.
183   void schedulePass(Pass *P);
184 
185   /// Set pass P as the last user of the given analysis passes.
186   void setLastUser(ArrayRef<Pass*> AnalysisPasses, Pass *P);
187 
188   /// Collect passes whose last user is P
189   void collectLastUses(SmallVectorImpl<Pass *> &LastUses, Pass *P);
190 
191   /// Find the pass that implements Analysis AID. Search immutable
192   /// passes and all pass managers. If desired pass is not found
193   /// then return NULL.
194   Pass *findAnalysisPass(AnalysisID AID);
195 
196   /// Retrieve the PassInfo for an analysis.
197   const PassInfo *findAnalysisPassInfo(AnalysisID AID) const;
198 
199   /// Find analysis usage information for the pass P.
200   AnalysisUsage *findAnalysisUsage(Pass *P);
201 
202   virtual ~PMTopLevelManager();
203 
204   /// Add immutable pass and initialize it.
205   void addImmutablePass(ImmutablePass *P);
206 
207   inline SmallVectorImpl<ImmutablePass *>& getImmutablePasses() {
208     return ImmutablePasses;
209   }
210 
211   void addPassManager(PMDataManager *Manager) {
212     PassManagers.push_back(Manager);
213   }
214 
215   // Add Manager into the list of managers that are not directly
216   // maintained by this top level pass manager
217   inline void addIndirectPassManager(PMDataManager *Manager) {
218     IndirectPassManagers.push_back(Manager);
219   }
220 
221   // Print passes managed by this top level manager.
222   void dumpPasses() const;
223   void dumpArguments() const;
224 
225   // Active Pass Managers
226   PMStack activeStack;
227 
228 protected:
229   /// Collection of pass managers
230   SmallVector<PMDataManager *, 8> PassManagers;
231 
232 private:
233   /// Collection of pass managers that are not directly maintained
234   /// by this pass manager
235   SmallVector<PMDataManager *, 8> IndirectPassManagers;
236 
237   // Map to keep track of last user of the analysis pass.
238   // LastUser->second is the last user of Lastuser->first.
239   DenseMap<Pass *, Pass *> LastUser;
240 
241   // Map to keep track of passes that are last used by a pass.
242   // This inverse map is initialized at PM->run() based on
243   // LastUser map.
244   DenseMap<Pass *, SmallPtrSet<Pass *, 8> > InversedLastUser;
245 
246   /// Immutable passes are managed by top level manager.
247   SmallVector<ImmutablePass *, 16> ImmutablePasses;
248 
249   /// Map from ID to immutable passes.
250   SmallDenseMap<AnalysisID, ImmutablePass *, 8> ImmutablePassMap;
251 
252 
253   /// A wrapper around AnalysisUsage for the purpose of uniqueing.  The wrapper
254   /// is used to avoid needing to make AnalysisUsage itself a folding set node.
255   struct AUFoldingSetNode : public FoldingSetNode {
256     AnalysisUsage AU;
257     AUFoldingSetNode(const AnalysisUsage &AU) : AU(AU) {}
258     void Profile(FoldingSetNodeID &ID) const {
259       Profile(ID, AU);
260     }
261     static void Profile(FoldingSetNodeID &ID, const AnalysisUsage &AU) {
262       // TODO: We could consider sorting the dependency arrays within the
263       // AnalysisUsage (since they are conceptually unordered).
264       ID.AddBoolean(AU.getPreservesAll());
265       auto ProfileVec = [&](const SmallVectorImpl<AnalysisID>& Vec) {
266         ID.AddInteger(Vec.size());
267         for(AnalysisID AID : Vec)
268           ID.AddPointer(AID);
269       };
270       ProfileVec(AU.getRequiredSet());
271       ProfileVec(AU.getRequiredTransitiveSet());
272       ProfileVec(AU.getPreservedSet());
273       ProfileVec(AU.getUsedSet());
274     }
275   };
276 
277   // Contains all of the unique combinations of AnalysisUsage.  This is helpful
278   // when we have multiple instances of the same pass since they'll usually
279   // have the same analysis usage and can share storage.
280   FoldingSet<AUFoldingSetNode> UniqueAnalysisUsages;
281 
282   // Allocator used for allocating UAFoldingSetNodes.  This handles deletion of
283   // all allocated nodes in one fell swoop.
284   SpecificBumpPtrAllocator<AUFoldingSetNode> AUFoldingSetNodeAllocator;
285 
286   // Maps from a pass to it's associated entry in UniqueAnalysisUsages.  Does
287   // not own the storage associated with either key or value..
288   DenseMap<Pass *, AnalysisUsage*> AnUsageMap;
289 
290   /// Collection of PassInfo objects found via analysis IDs and in this top
291   /// level manager. This is used to memoize queries to the pass registry.
292   /// FIXME: This is an egregious hack because querying the pass registry is
293   /// either slow or racy.
294   mutable DenseMap<AnalysisID, const PassInfo *> AnalysisPassInfos;
295 };
296 
297 //===----------------------------------------------------------------------===//
298 // PMDataManager
299 
300 /// PMDataManager provides the common place to manage the analysis data
301 /// used by pass managers.
302 class PMDataManager {
303 public:
304   explicit PMDataManager() : TPM(nullptr), Depth(0) {
305     initializeAnalysisInfo();
306   }
307 
308   virtual ~PMDataManager();
309 
310   virtual Pass *getAsPass() = 0;
311 
312   /// Augment AvailableAnalysis by adding analysis made available by pass P.
313   void recordAvailableAnalysis(Pass *P);
314 
315   /// verifyPreservedAnalysis -- Verify analysis presreved by pass P.
316   void verifyPreservedAnalysis(Pass *P);
317 
318   /// Remove Analysis that is not preserved by the pass
319   void removeNotPreservedAnalysis(Pass *P);
320 
321   /// Remove dead passes used by P.
322   void removeDeadPasses(Pass *P, StringRef Msg,
323                         enum PassDebuggingString);
324 
325   /// Remove P.
326   void freePass(Pass *P, StringRef Msg,
327                 enum PassDebuggingString);
328 
329   /// Add pass P into the PassVector. Update
330   /// AvailableAnalysis appropriately if ProcessAnalysis is true.
331   void add(Pass *P, bool ProcessAnalysis = true);
332 
333   /// Add RequiredPass into list of lower level passes required by pass P.
334   /// RequiredPass is run on the fly by Pass Manager when P requests it
335   /// through getAnalysis interface.
336   virtual void addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass);
337 
338   virtual Pass *getOnTheFlyPass(Pass *P, AnalysisID PI, Function &F);
339 
340   /// Initialize available analysis information.
341   void initializeAnalysisInfo() {
342     AvailableAnalysis.clear();
343     for (unsigned i = 0; i < PMT_Last; ++i)
344       InheritedAnalysis[i] = nullptr;
345   }
346 
347   // Return true if P preserves high level analysis used by other
348   // passes that are managed by this manager.
349   bool preserveHigherLevelAnalysis(Pass *P);
350 
351   /// Populate UsedPasses with analysis pass that are used or required by pass
352   /// P and are available. Populate ReqPassNotAvailable with analysis pass that
353   /// are required by pass P but are not available.
354   void collectRequiredAndUsedAnalyses(
355       SmallVectorImpl<Pass *> &UsedPasses,
356       SmallVectorImpl<AnalysisID> &ReqPassNotAvailable, Pass *P);
357 
358   /// All Required analyses should be available to the pass as it runs!  Here
359   /// we fill in the AnalysisImpls member of the pass so that it can
360   /// successfully use the getAnalysis() method to retrieve the
361   /// implementations it needs.
362   void initializeAnalysisImpl(Pass *P);
363 
364   /// Find the pass that implements Analysis AID. If desired pass is not found
365   /// then return NULL.
366   Pass *findAnalysisPass(AnalysisID AID, bool Direction);
367 
368   // Access toplevel manager
369   PMTopLevelManager *getTopLevelManager() { return TPM; }
370   void setTopLevelManager(PMTopLevelManager *T) { TPM = T; }
371 
372   unsigned getDepth() const { return Depth; }
373   void setDepth(unsigned newDepth) { Depth = newDepth; }
374 
375   // Print routines used by debug-pass
376   void dumpLastUses(Pass *P, unsigned Offset) const;
377   void dumpPassArguments() const;
378   void dumpPassInfo(Pass *P, enum PassDebuggingString S1,
379                     enum PassDebuggingString S2, StringRef Msg);
380   void dumpRequiredSet(const Pass *P) const;
381   void dumpPreservedSet(const Pass *P) const;
382   void dumpUsedSet(const Pass *P) const;
383 
384   unsigned getNumContainedPasses() const {
385     return (unsigned)PassVector.size();
386   }
387 
388   virtual PassManagerType getPassManagerType() const {
389     assert ( 0 && "Invalid use of getPassManagerType");
390     return PMT_Unknown;
391   }
392 
393   DenseMap<AnalysisID, Pass*> *getAvailableAnalysis() {
394     return &AvailableAnalysis;
395   }
396 
397   // Collect AvailableAnalysis from all the active Pass Managers.
398   void populateInheritedAnalysis(PMStack &PMS) {
399     unsigned Index = 0;
400     for (PMStack::iterator I = PMS.begin(), E = PMS.end();
401          I != E; ++I)
402       InheritedAnalysis[Index++] = (*I)->getAvailableAnalysis();
403   }
404 
405   /// Set the initial size of the module if the user has specified that they
406   /// want remarks for size.
407   /// Returns 0 if the remark was not requested.
408   unsigned initSizeRemarkInfo(
409       Module &M,
410       StringMap<std::pair<unsigned, unsigned>> &FunctionToInstrCount);
411 
412   /// Emit a remark signifying that the number of IR instructions in the module
413   /// changed.
414   /// \p F is optionally passed by passes which run on Functions, and thus
415   /// always know whether or not a non-empty function is available.
416   ///
417   /// \p FunctionToInstrCount maps the name of a \p Function to a pair. The
418   /// first member of the pair is the IR count of the \p Function before running
419   /// \p P, and the second member is the IR count of the \p Function after
420   /// running \p P.
421   void emitInstrCountChangedRemark(
422       Pass *P, Module &M, int64_t Delta, unsigned CountBefore,
423       StringMap<std::pair<unsigned, unsigned>> &FunctionToInstrCount,
424       Function *F = nullptr);
425 
426 protected:
427   // Top level manager.
428   PMTopLevelManager *TPM;
429 
430   // Collection of pass that are managed by this manager
431   SmallVector<Pass *, 16> PassVector;
432 
433   // Collection of Analysis provided by Parent pass manager and
434   // used by current pass manager. At at time there can not be more
435   // then PMT_Last active pass mangers.
436   DenseMap<AnalysisID, Pass *> *InheritedAnalysis[PMT_Last];
437 
438   /// isPassDebuggingExecutionsOrMore - Return true if -debug-pass=Executions
439   /// or higher is specified.
440   bool isPassDebuggingExecutionsOrMore() const;
441 
442 private:
443   void dumpAnalysisUsage(StringRef Msg, const Pass *P,
444                          const AnalysisUsage::VectorType &Set) const;
445 
446   // Set of available Analysis. This information is used while scheduling
447   // pass. If a pass requires an analysis which is not available then
448   // the required analysis pass is scheduled to run before the pass itself is
449   // scheduled to run.
450   DenseMap<AnalysisID, Pass*> AvailableAnalysis;
451 
452   // Collection of higher level analysis used by the pass managed by
453   // this manager.
454   SmallVector<Pass *, 16> HigherLevelAnalysis;
455 
456   unsigned Depth;
457 };
458 
459 //===----------------------------------------------------------------------===//
460 // FPPassManager
461 //
462 /// FPPassManager manages BBPassManagers and FunctionPasses.
463 /// It batches all function passes and basic block pass managers together and
464 /// sequence them to process one function at a time before processing next
465 /// function.
466 class FPPassManager : public ModulePass, public PMDataManager {
467 public:
468   static char ID;
469   explicit FPPassManager()
470   : ModulePass(ID), PMDataManager() { }
471 
472   /// run - Execute all of the passes scheduled for execution.  Keep track of
473   /// whether any of the passes modifies the module, and if so, return true.
474   bool runOnFunction(Function &F);
475   bool runOnModule(Module &M) override;
476 
477   /// cleanup - After running all passes, clean up pass manager cache.
478   void cleanup();
479 
480   /// doInitialization - Overrides ModulePass doInitialization for global
481   /// initialization tasks
482   ///
483   using ModulePass::doInitialization;
484 
485   /// doInitialization - Run all of the initializers for the function passes.
486   ///
487   bool doInitialization(Module &M) override;
488 
489   /// doFinalization - Overrides ModulePass doFinalization for global
490   /// finalization tasks
491   ///
492   using ModulePass::doFinalization;
493 
494   /// doFinalization - Run all of the finalizers for the function passes.
495   ///
496   bool doFinalization(Module &M) override;
497 
498   PMDataManager *getAsPMDataManager() override { return this; }
499   Pass *getAsPass() override { return this; }
500 
501   /// Pass Manager itself does not invalidate any analysis info.
502   void getAnalysisUsage(AnalysisUsage &Info) const override {
503     Info.setPreservesAll();
504   }
505 
506   // Print passes managed by this manager
507   void dumpPassStructure(unsigned Offset) override;
508 
509   StringRef getPassName() const override { return "Function Pass Manager"; }
510 
511   FunctionPass *getContainedPass(unsigned N) {
512     assert ( N < PassVector.size() && "Pass number out of range!");
513     FunctionPass *FP = static_cast<FunctionPass *>(PassVector[N]);
514     return FP;
515   }
516 
517   PassManagerType getPassManagerType() const override {
518     return PMT_FunctionPassManager;
519   }
520 };
521 
522 }
523 
524 #endif
525