1 //===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a base class that indicates that a specified class is a
11 // transformation pass implementation.
13 // Passes are designed this way so that it is possible to run passes in a cache
14 // and organizationally optimal order without having to specify it at the front
15 // end. This allows arbitrary passes to be strung together and have them
16 // executed as effeciently as possible.
18 // Passes should extend one of the classes below, depending on the guarantees
19 // that it can make about what will be modified as it is run. For example, most
20 // global optimizations should derive from FunctionPass, because they do not add
21 // or delete functions, they operate on the internals of the function.
23 // Note that this file #includes PassSupport.h and PassAnalysisSupport.h (at the
24 // bottom), so the APIs exposed by these files are also automatically available
25 // to all users of this file.
27 //===----------------------------------------------------------------------===//
32 #include "llvm/Support/Streams.h"
49 class BasicBlockPassManager;
50 class ModulePassManager;
52 class AnalysisResolver;
55 // AnalysisID - Use the PassInfo to identify a pass...
56 typedef const PassInfo* AnalysisID;
58 /// Different types of internal pass managers. External pass managers
59 /// (PassManager and FunctionPassManager) are not represented here.
60 /// Ordering of pass manager types is important here.
61 enum PassManagerType {
63 PMT_ModulePassManager = 1, /// MPPassManager
64 PMT_CallGraphPassManager, /// CGPassManager
65 PMT_FunctionPassManager, /// FPPassManager
66 PMT_LoopPassManager, /// LPPassManager
67 PMT_BasicBlockPassManager, /// BBPassManager
71 typedef enum PassManagerType PassManagerType;
73 //===----------------------------------------------------------------------===//
74 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
75 /// interprocedural optimization or you do not fit into any of the more
76 /// constrained passes described below.
79 AnalysisResolver *Resolver; // Used to resolve analysis
80 const PassInfo *PassInfoCache;
82 // AnalysisImpls - This keeps track of which passes implement the interfaces
83 // that are required by the current pass (to implement getAnalysis()).
85 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
87 void operator=(const Pass&); // DO NOT IMPLEMENT
88 Pass(const Pass &); // DO NOT IMPLEMENT
90 Pass() : Resolver(0), PassInfoCache(0) {}
91 virtual ~Pass() {} // Destructor is virtual so we can be subclassed
93 /// getPassName - Return a nice clean name for a pass. This usually
94 /// implemented in terms of the name that is registered by one of the
95 /// Registration templates, but can be overloaded directly, and if nothing
96 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
97 /// intelligible name for the pass.
99 virtual const char *getPassName() const;
101 /// getPassInfo - Return the PassInfo data structure that corresponds to this
102 /// pass... If the pass has not been registered, this will return null.
104 const PassInfo *getPassInfo() const;
106 /// runPass - Run this pass, returning true if a modification was made to the
107 /// module argument. This should be implemented by all concrete subclasses.
109 virtual bool runPass(Module &M) { return false; }
110 virtual bool runPass(BasicBlock&) { return false; }
112 /// print - Print out the internal state of the pass. This is called by
113 /// Analyze to print out the contents of an analysis. Otherwise it is not
114 /// necessary to implement this method. Beware that the module pointer MAY be
115 /// null. This automatically forwards to a virtual function that does not
116 /// provide the Module* in case the analysis doesn't need it it can just be
119 virtual void print(std::ostream &O, const Module *M) const;
120 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
121 void dump() const; // dump - call print(std::cerr, 0);
123 /// Each pass is responsible for assigning a pass manager to itself.
124 /// PMS is the stack of available pass manager.
125 virtual void assignPassManager(PMStack &PMS,
126 PassManagerType T = PMT_Unknown) {}
127 /// Check if available pass managers are suitable for this pass or not.
128 virtual void preparePassManager(PMStack &PMS) {}
130 /// Return what kind of Pass Manager can manage this pass.
131 virtual PassManagerType getPotentialPassManagerType() const {
135 // Access AnalysisResolver
136 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; }
137 inline AnalysisResolver *getResolver() { return Resolver; }
139 /// getAnalysisUsage - This function should be overriden by passes that need
140 /// analysis information to do their job. If a pass specifies that it uses a
141 /// particular analysis result to this function, it can then use the
142 /// getAnalysis<AnalysisType>() function, below.
144 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
145 // By default, no analysis results are used, all are invalidated.
148 /// releaseMemory() - This member can be implemented by a pass if it wants to
149 /// be able to release its memory when it is no longer needed. The default
150 /// behavior of passes is to hold onto memory for the entire duration of their
151 /// lifetime (which is the entire compile time). For pipelined passes, this
152 /// is not a big deal because that memory gets recycled every time the pass is
153 /// invoked on another program unit. For IP passes, it is more important to
154 /// free memory when it is unused.
156 /// Optionally implement this function to release pass memory when it is no
159 virtual void releaseMemory() {}
161 // dumpPassStructure - Implement the -debug-passes=PassStructure option
162 virtual void dumpPassStructure(unsigned Offset = 0);
164 template<typename AnalysisClass>
165 static const PassInfo *getClassPassInfo() {
166 return lookupPassInfo(typeid(AnalysisClass));
169 // lookupPassInfo - Return the pass info object for the specified pass class,
170 // or null if it is not known.
171 static const PassInfo *lookupPassInfo(const std::type_info &TI);
173 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
174 /// to get to the analysis information that might be around that needs to be
175 /// updated. This is different than getAnalysis in that it can fail (ie the
176 /// analysis results haven't been computed), so should only be used if you
177 /// provide the capability to update an analysis that exists. This method is
178 /// often used by transformation APIs to update analysis results for a pass
179 /// automatically as the transform is performed.
181 template<typename AnalysisType>
182 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
184 /// mustPreserveAnalysisID - This method serves the same function as
185 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
186 /// obviously cannot give you a properly typed instance of the class if you
187 /// don't have the class name available (use getAnalysisToUpdate if you do),
188 /// but it can tell you if you need to preserve the pass at least.
190 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
192 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
193 /// to the analysis information that they claim to use by overriding the
194 /// getAnalysisUsage function.
196 template<typename AnalysisType>
197 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
199 template<typename AnalysisType>
200 AnalysisType &getAnalysisID(const PassInfo *PI) const;
204 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
205 P.print(OS, 0); return OS;
208 //===----------------------------------------------------------------------===//
209 /// ModulePass class - This class is used to implement unstructured
210 /// interprocedural optimizations and analyses. ModulePasses may do anything
211 /// they want to the program.
213 class ModulePass : public Pass {
215 /// runOnModule - Virtual method overriden by subclasses to process the module
216 /// being operated on.
217 virtual bool runOnModule(Module &M) = 0;
219 virtual bool runPass(Module &M) { return runOnModule(M); }
220 virtual bool runPass(BasicBlock&) { return false; }
222 virtual void assignPassManager(PMStack &PMS,
223 PassManagerType T = PMT_ModulePassManager);
225 /// Return what kind of Pass Manager can manage this pass.
226 virtual PassManagerType getPotentialPassManagerType() const {
227 return PMT_ModulePassManager;
230 // Force out-of-line virtual method.
231 virtual ~ModulePass();
235 //===----------------------------------------------------------------------===//
236 /// ImmutablePass class - This class is used to provide information that does
237 /// not need to be run. This is useful for things like target information and
238 /// "basic" versions of AnalysisGroups.
240 class ImmutablePass : public ModulePass {
242 /// initializePass - This method may be overriden by immutable passes to allow
243 /// them to perform various initialization actions they require. This is
244 /// primarily because an ImmutablePass can "require" another ImmutablePass,
245 /// and if it does, the overloaded version of initializePass may get access to
246 /// these passes with getAnalysis<>.
248 virtual void initializePass() {}
250 /// ImmutablePasses are never run.
252 virtual bool runOnModule(Module &M) { return false; }
254 // Force out-of-line virtual method.
255 virtual ~ImmutablePass();
258 //===----------------------------------------------------------------------===//
259 /// FunctionPass class - This class is used to implement most global
260 /// optimizations. Optimizations should subclass this class if they meet the
261 /// following constraints:
263 /// 1. Optimizations are organized globally, i.e., a function at a time
264 /// 2. Optimizing a function does not cause the addition or removal of any
265 /// functions in the module
267 class FunctionPass : public Pass {
269 /// doInitialization - Virtual method overridden by subclasses to do
270 /// any necessary per-module initialization.
272 virtual bool doInitialization(Module &M) { return false; }
274 /// runOnFunction - Virtual method overriden by subclasses to do the
275 /// per-function processing of the pass.
277 virtual bool runOnFunction(Function &F) = 0;
279 /// doFinalization - Virtual method overriden by subclasses to do any post
280 /// processing needed after all passes have run.
282 virtual bool doFinalization(Module &M) { return false; }
284 /// runOnModule - On a module, we run this pass by initializing,
285 /// ronOnFunction'ing once for every function in the module, then by
288 virtual bool runOnModule(Module &M);
290 /// run - On a function, we simply initialize, run the function, then
293 bool run(Function &F);
295 virtual void assignPassManager(PMStack &PMS,
296 PassManagerType T = PMT_FunctionPassManager);
298 /// Return what kind of Pass Manager can manage this pass.
299 virtual PassManagerType getPotentialPassManagerType() const {
300 return PMT_FunctionPassManager;
306 //===----------------------------------------------------------------------===//
307 /// BasicBlockPass class - This class is used to implement most local
308 /// optimizations. Optimizations should subclass this class if they
309 /// meet the following constraints:
310 /// 1. Optimizations are local, operating on either a basic block or
311 /// instruction at a time.
312 /// 2. Optimizations do not modify the CFG of the contained function, or any
313 /// other basic block in the function.
314 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
316 class BasicBlockPass : public Pass {
318 /// doInitialization - Virtual method overridden by subclasses to do
319 /// any necessary per-module initialization.
321 virtual bool doInitialization(Module &M) { return false; }
323 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
324 /// to do any necessary per-function initialization.
326 virtual bool doInitialization(Function &F) { return false; }
328 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
329 /// per-basicblock processing of the pass.
331 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
333 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
334 /// do any post processing needed after all passes have run.
336 virtual bool doFinalization(Function &F) { return false; }
338 /// doFinalization - Virtual method overriden by subclasses to do any post
339 /// processing needed after all passes have run.
341 virtual bool doFinalization(Module &M) { return false; }
344 // To run this pass on a function, we simply call runOnBasicBlock once for
347 bool runOnFunction(Function &F);
349 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
352 virtual bool runPass(Module &M) { return false; }
353 virtual bool runPass(BasicBlock &BB);
355 virtual void assignPassManager(PMStack &PMS,
356 PassManagerType T = PMT_BasicBlockPassManager);
358 /// Return what kind of Pass Manager can manage this pass.
359 virtual PassManagerType getPotentialPassManagerType() const {
360 return PMT_BasicBlockPassManager;
365 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
366 /// using PMStack. Each Pass implements assignPassManager() to connect itself
367 /// with appropriate manager. assignPassManager() walks PMStack to find
368 /// suitable manager.
370 /// PMStack is just a wrapper around standard deque that overrides pop() and
374 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
375 iterator begin() { return S.rbegin(); }
376 iterator end() { return S.rend(); }
378 void handleLastUserOverflow();
381 inline PMDataManager *top() { return S.back(); }
383 inline bool empty() { return S.empty(); }
387 std::deque<PMDataManager *> S;
391 /// If the user specifies the -time-passes argument on an LLVM tool command line
392 /// then the value of this boolean will be true, otherwise false.
393 /// @brief This is the storage for the -time-passes option.
394 extern bool TimePassesIsEnabled;
396 } // End llvm namespace
398 // Include support files that contain important APIs commonly used by Passes,
399 // but that we want to separate out to make it easier to read the header files.
401 #include "llvm/PassSupport.h"
402 #include "llvm/PassAnalysisSupport.h"