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 template<class Trait> class PassManagerT;
50 class BasicBlockPassManager;
51 class FunctionPassManagerT;
52 class ModulePassManager;
54 class AnalysisResolver;
56 // AnalysisID - Use the PassInfo to identify a pass...
57 typedef const PassInfo* AnalysisID;
59 //===----------------------------------------------------------------------===//
60 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
61 /// interprocedural optimization or you do not fit into any of the more
62 /// constrained passes described below.
65 AnalysisResolver *Resolver; // Used to resolve analysis
66 const PassInfo *PassInfoCache;
68 // AnalysisImpls - This keeps track of which passes implement the interfaces
69 // that are required by the current pass (to implement getAnalysis()).
71 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
73 void operator=(const Pass&); // DO NOT IMPLEMENT
74 Pass(const Pass &); // DO NOT IMPLEMENT
76 Pass() : Resolver(0), PassInfoCache(0) {}
77 virtual ~Pass() {} // Destructor is virtual so we can be subclassed
79 /// getPassName - Return a nice clean name for a pass. This usually
80 /// implemented in terms of the name that is registered by one of the
81 /// Registration templates, but can be overloaded directly, and if nothing
82 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
83 /// intelligible name for the pass.
85 virtual const char *getPassName() const;
87 /// getPassInfo - Return the PassInfo data structure that corresponds to this
88 /// pass... If the pass has not been registered, this will return null.
90 const PassInfo *getPassInfo() const;
92 /// runPass - Run this pass, returning true if a modification was made to the
93 /// module argument. This should be implemented by all concrete subclasses.
95 virtual bool runPass(Module &M) { return false; }
96 virtual bool runPass(BasicBlock&) { return false; }
98 /// print - Print out the internal state of the pass. This is called by
99 /// Analyze to print out the contents of an analysis. Otherwise it is not
100 /// necessary to implement this method. Beware that the module pointer MAY be
101 /// null. This automatically forwards to a virtual function that does not
102 /// provide the Module* in case the analysis doesn't need it it can just be
105 virtual void print(std::ostream &O, const Module *M) const;
106 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
107 void dump() const; // dump - call print(std::cerr, 0);
109 // Access AnalysisResolver
110 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; }
111 inline AnalysisResolver *getResolver() { return Resolver; }
113 /// getAnalysisUsage - This function should be overriden by passes that need
114 /// analysis information to do their job. If a pass specifies that it uses a
115 /// particular analysis result to this function, it can then use the
116 /// getAnalysis<AnalysisType>() function, below.
118 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
119 // By default, no analysis results are used, all are invalidated.
122 /// releaseMemory() - This member can be implemented by a pass if it wants to
123 /// be able to release its memory when it is no longer needed. The default
124 /// behavior of passes is to hold onto memory for the entire duration of their
125 /// lifetime (which is the entire compile time). For pipelined passes, this
126 /// is not a big deal because that memory gets recycled every time the pass is
127 /// invoked on another program unit. For IP passes, it is more important to
128 /// free memory when it is unused.
130 /// Optionally implement this function to release pass memory when it is no
133 virtual void releaseMemory() {}
135 // dumpPassStructure - Implement the -debug-passes=PassStructure option
136 virtual void dumpPassStructure(unsigned Offset = 0);
138 template<typename AnalysisClass>
139 static const PassInfo *getClassPassInfo() {
140 return lookupPassInfo(typeid(AnalysisClass));
143 // lookupPassInfo - Return the pass info object for the specified pass class,
144 // or null if it is not known.
145 static const PassInfo *lookupPassInfo(const std::type_info &TI);
147 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
148 /// to get to the analysis information that might be around that needs to be
149 /// updated. This is different than getAnalysis in that it can fail (ie the
150 /// analysis results haven't been computed), so should only be used if you
151 /// provide the capability to update an analysis that exists. This method is
152 /// often used by transformation APIs to update analysis results for a pass
153 /// automatically as the transform is performed.
155 template<typename AnalysisType>
156 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
158 /// mustPreserveAnalysisID - This method serves the same function as
159 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
160 /// obviously cannot give you a properly typed instance of the class if you
161 /// don't have the class name available (use getAnalysisToUpdate if you do),
162 /// but it can tell you if you need to preserve the pass at least.
164 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
166 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
167 /// to the analysis information that they claim to use by overriding the
168 /// getAnalysisUsage function.
170 template<typename AnalysisType>
171 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
173 template<typename AnalysisType>
174 AnalysisType &getAnalysisID(const PassInfo *PI) const;
177 template<typename Trait> friend class PassManagerT;
178 friend class ModulePassManager;
179 friend class FunctionPassManagerT;
180 friend class BasicBlockPassManager;
183 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
184 P.print(OS, 0); return OS;
187 //===----------------------------------------------------------------------===//
188 /// ModulePass class - This class is used to implement unstructured
189 /// interprocedural optimizations and analyses. ModulePasses may do anything
190 /// they want to the program.
192 class ModulePass : public Pass {
194 /// runOnModule - Virtual method overriden by subclasses to process the module
195 /// being operated on.
196 virtual bool runOnModule(Module &M) = 0;
198 virtual bool runPass(Module &M) { return runOnModule(M); }
199 virtual bool runPass(BasicBlock&) { return false; }
201 virtual void assignPassManager(PMStack &PMS);
202 // Force out-of-line virtual method.
203 virtual ~ModulePass();
207 //===----------------------------------------------------------------------===//
208 /// ImmutablePass class - This class is used to provide information that does
209 /// not need to be run. This is useful for things like target information and
210 /// "basic" versions of AnalysisGroups.
212 class ImmutablePass : public ModulePass {
214 /// initializePass - This method may be overriden by immutable passes to allow
215 /// them to perform various initialization actions they require. This is
216 /// primarily because an ImmutablePass can "require" another ImmutablePass,
217 /// and if it does, the overloaded version of initializePass may get access to
218 /// these passes with getAnalysis<>.
220 virtual void initializePass() {}
222 /// ImmutablePasses are never run.
224 virtual bool runOnModule(Module &M) { return false; }
226 // Force out-of-line virtual method.
227 virtual ~ImmutablePass();
230 //===----------------------------------------------------------------------===//
231 /// FunctionPass class - This class is used to implement most global
232 /// optimizations. Optimizations should subclass this class if they meet the
233 /// following constraints:
235 /// 1. Optimizations are organized globally, i.e., a function at a time
236 /// 2. Optimizing a function does not cause the addition or removal of any
237 /// functions in the module
239 class FunctionPass : public ModulePass {
241 /// doInitialization - Virtual method overridden by subclasses to do
242 /// any necessary per-module initialization.
244 virtual bool doInitialization(Module &M) { return false; }
246 /// runOnFunction - Virtual method overriden by subclasses to do the
247 /// per-function processing of the pass.
249 virtual bool runOnFunction(Function &F) = 0;
251 /// doFinalization - Virtual method overriden by subclasses to do any post
252 /// processing needed after all passes have run.
254 virtual bool doFinalization(Module &M) { return false; }
256 /// runOnModule - On a module, we run this pass by initializing,
257 /// ronOnFunction'ing once for every function in the module, then by
260 virtual bool runOnModule(Module &M);
262 /// run - On a function, we simply initialize, run the function, then
265 bool run(Function &F);
267 virtual void assignPassManager(PMStack &PMS);
272 //===----------------------------------------------------------------------===//
273 /// BasicBlockPass class - This class is used to implement most local
274 /// optimizations. Optimizations should subclass this class if they
275 /// meet the following constraints:
276 /// 1. Optimizations are local, operating on either a basic block or
277 /// instruction at a time.
278 /// 2. Optimizations do not modify the CFG of the contained function, or any
279 /// other basic block in the function.
280 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
282 class BasicBlockPass : public FunctionPass {
284 /// doInitialization - Virtual method overridden by subclasses to do
285 /// any necessary per-module initialization.
287 virtual bool doInitialization(Module &M) { return false; }
289 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
290 /// to do any necessary per-function initialization.
292 virtual bool doInitialization(Function &F) { return false; }
294 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
295 /// per-basicblock processing of the pass.
297 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
299 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
300 /// do any post processing needed after all passes have run.
302 virtual bool doFinalization(Function &F) { return false; }
304 /// doFinalization - Virtual method overriden by subclasses to do any post
305 /// processing needed after all passes have run.
307 virtual bool doFinalization(Module &M) { return false; }
310 // To run this pass on a function, we simply call runOnBasicBlock once for
313 bool runOnFunction(Function &F);
315 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
318 virtual bool runPass(Module &M) { return false; }
319 virtual bool runPass(BasicBlock &BB);
321 virtual void assignPassManager(PMStack &PMS);
325 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
326 /// using PMStack. Each Pass implements assignPassManager() to connect itself
327 /// with appropriate manager. assignPassManager() walks PMStack to find
328 /// suitable manager.
330 /// PMStack is just a wrapper around standard deque that overrides pop() and
335 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
336 iterator begin() { return S.rbegin(); }
337 iterator end() { return S.rend(); }
339 void handleLastUserOverflow();
342 inline PMDataManager *top() { return S.back(); }
343 void push(PMDataManager *PM);
344 inline bool empty() { return S.empty(); }
347 std::deque<PMDataManager *> S;
351 /// If the user specifies the -time-passes argument on an LLVM tool command line
352 /// then the value of this boolean will be true, otherwise false.
353 /// @brief This is the storage for the -time-passes option.
354 extern bool TimePassesIsEnabled;
356 } // End llvm namespace
358 // Include support files that contain important APIs commonly used by Passes,
359 // but that we want to separate out to make it easier to read the header files.
361 #include "llvm/PassSupport.h"
362 #include "llvm/PassAnalysisSupport.h"