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
70 typedef enum PassManagerType PassManagerType;
72 //===----------------------------------------------------------------------===//
73 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
74 /// interprocedural optimization or you do not fit into any of the more
75 /// constrained passes described below.
78 AnalysisResolver *Resolver; // Used to resolve analysis
79 const PassInfo *PassInfoCache;
81 // AnalysisImpls - This keeps track of which passes implement the interfaces
82 // that are required by the current pass (to implement getAnalysis()).
84 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
86 void operator=(const Pass&); // DO NOT IMPLEMENT
87 Pass(const Pass &); // DO NOT IMPLEMENT
89 Pass() : Resolver(0), PassInfoCache(0) {}
90 virtual ~Pass() {} // Destructor is virtual so we can be subclassed
92 /// getPassName - Return a nice clean name for a pass. This usually
93 /// implemented in terms of the name that is registered by one of the
94 /// Registration templates, but can be overloaded directly, and if nothing
95 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
96 /// intelligible name for the pass.
98 virtual const char *getPassName() const;
100 /// getPassInfo - Return the PassInfo data structure that corresponds to this
101 /// pass... If the pass has not been registered, this will return null.
103 const PassInfo *getPassInfo() const;
105 /// runPass - Run this pass, returning true if a modification was made to the
106 /// module argument. This should be implemented by all concrete subclasses.
108 virtual bool runPass(Module &M) { return false; }
109 virtual bool runPass(BasicBlock&) { return false; }
111 /// print - Print out the internal state of the pass. This is called by
112 /// Analyze to print out the contents of an analysis. Otherwise it is not
113 /// necessary to implement this method. Beware that the module pointer MAY be
114 /// null. This automatically forwards to a virtual function that does not
115 /// provide the Module* in case the analysis doesn't need it it can just be
118 virtual void print(std::ostream &O, const Module *M) const;
119 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
120 void dump() const; // dump - call print(std::cerr, 0);
122 virtual void assignPassManager(PMStack &PMS,
123 PassManagerType T = PMT_Unknown) {}
124 // Access AnalysisResolver
125 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; }
126 inline AnalysisResolver *getResolver() { return Resolver; }
128 /// getAnalysisUsage - This function should be overriden by passes that need
129 /// analysis information to do their job. If a pass specifies that it uses a
130 /// particular analysis result to this function, it can then use the
131 /// getAnalysis<AnalysisType>() function, below.
133 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
134 // By default, no analysis results are used, all are invalidated.
137 /// releaseMemory() - This member can be implemented by a pass if it wants to
138 /// be able to release its memory when it is no longer needed. The default
139 /// behavior of passes is to hold onto memory for the entire duration of their
140 /// lifetime (which is the entire compile time). For pipelined passes, this
141 /// is not a big deal because that memory gets recycled every time the pass is
142 /// invoked on another program unit. For IP passes, it is more important to
143 /// free memory when it is unused.
145 /// Optionally implement this function to release pass memory when it is no
148 virtual void releaseMemory() {}
150 // dumpPassStructure - Implement the -debug-passes=PassStructure option
151 virtual void dumpPassStructure(unsigned Offset = 0);
153 template<typename AnalysisClass>
154 static const PassInfo *getClassPassInfo() {
155 return lookupPassInfo(typeid(AnalysisClass));
158 // lookupPassInfo - Return the pass info object for the specified pass class,
159 // or null if it is not known.
160 static const PassInfo *lookupPassInfo(const std::type_info &TI);
162 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
163 /// to get to the analysis information that might be around that needs to be
164 /// updated. This is different than getAnalysis in that it can fail (ie the
165 /// analysis results haven't been computed), so should only be used if you
166 /// provide the capability to update an analysis that exists. This method is
167 /// often used by transformation APIs to update analysis results for a pass
168 /// automatically as the transform is performed.
170 template<typename AnalysisType>
171 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
173 /// mustPreserveAnalysisID - This method serves the same function as
174 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
175 /// obviously cannot give you a properly typed instance of the class if you
176 /// don't have the class name available (use getAnalysisToUpdate if you do),
177 /// but it can tell you if you need to preserve the pass at least.
179 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
181 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
182 /// to the analysis information that they claim to use by overriding the
183 /// getAnalysisUsage function.
185 template<typename AnalysisType>
186 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
188 template<typename AnalysisType>
189 AnalysisType &getAnalysisID(const PassInfo *PI) const;
193 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
194 P.print(OS, 0); return OS;
197 //===----------------------------------------------------------------------===//
198 /// ModulePass class - This class is used to implement unstructured
199 /// interprocedural optimizations and analyses. ModulePasses may do anything
200 /// they want to the program.
202 class ModulePass : public Pass {
204 /// runOnModule - Virtual method overriden by subclasses to process the module
205 /// being operated on.
206 virtual bool runOnModule(Module &M) = 0;
208 virtual bool runPass(Module &M) { return runOnModule(M); }
209 virtual bool runPass(BasicBlock&) { return false; }
211 virtual void assignPassManager(PMStack &PMS,
212 PassManagerType T = PMT_ModulePassManager);
213 // Force out-of-line virtual method.
214 virtual ~ModulePass();
218 //===----------------------------------------------------------------------===//
219 /// ImmutablePass class - This class is used to provide information that does
220 /// not need to be run. This is useful for things like target information and
221 /// "basic" versions of AnalysisGroups.
223 class ImmutablePass : public ModulePass {
225 /// initializePass - This method may be overriden by immutable passes to allow
226 /// them to perform various initialization actions they require. This is
227 /// primarily because an ImmutablePass can "require" another ImmutablePass,
228 /// and if it does, the overloaded version of initializePass may get access to
229 /// these passes with getAnalysis<>.
231 virtual void initializePass() {}
233 /// ImmutablePasses are never run.
235 virtual bool runOnModule(Module &M) { return false; }
237 // Force out-of-line virtual method.
238 virtual ~ImmutablePass();
241 //===----------------------------------------------------------------------===//
242 /// FunctionPass class - This class is used to implement most global
243 /// optimizations. Optimizations should subclass this class if they meet the
244 /// following constraints:
246 /// 1. Optimizations are organized globally, i.e., a function at a time
247 /// 2. Optimizing a function does not cause the addition or removal of any
248 /// functions in the module
250 class FunctionPass : public Pass {
252 /// doInitialization - Virtual method overridden by subclasses to do
253 /// any necessary per-module initialization.
255 virtual bool doInitialization(Module &M) { return false; }
257 /// runOnFunction - Virtual method overriden by subclasses to do the
258 /// per-function processing of the pass.
260 virtual bool runOnFunction(Function &F) = 0;
262 /// doFinalization - Virtual method overriden by subclasses to do any post
263 /// processing needed after all passes have run.
265 virtual bool doFinalization(Module &M) { return false; }
267 /// runOnModule - On a module, we run this pass by initializing,
268 /// ronOnFunction'ing once for every function in the module, then by
271 virtual bool runOnModule(Module &M);
273 /// run - On a function, we simply initialize, run the function, then
276 bool run(Function &F);
278 virtual void assignPassManager(PMStack &PMS,
279 PassManagerType T = PMT_FunctionPassManager);
284 //===----------------------------------------------------------------------===//
285 /// BasicBlockPass class - This class is used to implement most local
286 /// optimizations. Optimizations should subclass this class if they
287 /// meet the following constraints:
288 /// 1. Optimizations are local, operating on either a basic block or
289 /// instruction at a time.
290 /// 2. Optimizations do not modify the CFG of the contained function, or any
291 /// other basic block in the function.
292 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
294 class BasicBlockPass : public Pass {
296 /// doInitialization - Virtual method overridden by subclasses to do
297 /// any necessary per-module initialization.
299 virtual bool doInitialization(Module &M) { return false; }
301 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
302 /// to do any necessary per-function initialization.
304 virtual bool doInitialization(Function &F) { return false; }
306 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
307 /// per-basicblock processing of the pass.
309 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
311 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
312 /// do any post processing needed after all passes have run.
314 virtual bool doFinalization(Function &F) { return false; }
316 /// doFinalization - Virtual method overriden by subclasses to do any post
317 /// processing needed after all passes have run.
319 virtual bool doFinalization(Module &M) { return false; }
322 // To run this pass on a function, we simply call runOnBasicBlock once for
325 bool runOnFunction(Function &F);
327 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
330 virtual bool runPass(Module &M) { return false; }
331 virtual bool runPass(BasicBlock &BB);
333 virtual void assignPassManager(PMStack &PMS,
334 PassManagerType T = PMT_BasicBlockPassManager);
338 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
339 /// using PMStack. Each Pass implements assignPassManager() to connect itself
340 /// with appropriate manager. assignPassManager() walks PMStack to find
341 /// suitable manager.
343 /// PMStack is just a wrapper around standard deque that overrides pop() and
347 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
348 iterator begin() { return S.rbegin(); }
349 iterator end() { return S.rend(); }
351 void handleLastUserOverflow();
354 inline PMDataManager *top() { return S.back(); }
356 inline bool empty() { return S.empty(); }
360 std::deque<PMDataManager *> S;
364 /// If the user specifies the -time-passes argument on an LLVM tool command line
365 /// then the value of this boolean will be true, otherwise false.
366 /// @brief This is the storage for the -time-passes option.
367 extern bool TimePassesIsEnabled;
369 } // End llvm namespace
371 // Include support files that contain important APIs commonly used by Passes,
372 // but that we want to separate out to make it easier to read the header files.
374 #include "llvm/PassSupport.h"
375 #include "llvm/PassAnalysisSupport.h"