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 // Access AnalysisResolver
131 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; }
132 inline AnalysisResolver *getResolver() { return Resolver; }
134 /// getAnalysisUsage - This function should be overriden by passes that need
135 /// analysis information to do their job. If a pass specifies that it uses a
136 /// particular analysis result to this function, it can then use the
137 /// getAnalysis<AnalysisType>() function, below.
139 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
140 // By default, no analysis results are used, all are invalidated.
143 /// releaseMemory() - This member can be implemented by a pass if it wants to
144 /// be able to release its memory when it is no longer needed. The default
145 /// behavior of passes is to hold onto memory for the entire duration of their
146 /// lifetime (which is the entire compile time). For pipelined passes, this
147 /// is not a big deal because that memory gets recycled every time the pass is
148 /// invoked on another program unit. For IP passes, it is more important to
149 /// free memory when it is unused.
151 /// Optionally implement this function to release pass memory when it is no
154 virtual void releaseMemory() {}
156 // dumpPassStructure - Implement the -debug-passes=PassStructure option
157 virtual void dumpPassStructure(unsigned Offset = 0);
159 template<typename AnalysisClass>
160 static const PassInfo *getClassPassInfo() {
161 return lookupPassInfo(typeid(AnalysisClass));
164 // lookupPassInfo - Return the pass info object for the specified pass class,
165 // or null if it is not known.
166 static const PassInfo *lookupPassInfo(const std::type_info &TI);
168 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
169 /// to get to the analysis information that might be around that needs to be
170 /// updated. This is different than getAnalysis in that it can fail (ie the
171 /// analysis results haven't been computed), so should only be used if you
172 /// provide the capability to update an analysis that exists. This method is
173 /// often used by transformation APIs to update analysis results for a pass
174 /// automatically as the transform is performed.
176 template<typename AnalysisType>
177 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
179 /// mustPreserveAnalysisID - This method serves the same function as
180 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
181 /// obviously cannot give you a properly typed instance of the class if you
182 /// don't have the class name available (use getAnalysisToUpdate if you do),
183 /// but it can tell you if you need to preserve the pass at least.
185 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
187 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
188 /// to the analysis information that they claim to use by overriding the
189 /// getAnalysisUsage function.
191 template<typename AnalysisType>
192 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
194 template<typename AnalysisType>
195 AnalysisType &getAnalysisID(const PassInfo *PI) const;
199 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
200 P.print(OS, 0); return OS;
203 //===----------------------------------------------------------------------===//
204 /// ModulePass class - This class is used to implement unstructured
205 /// interprocedural optimizations and analyses. ModulePasses may do anything
206 /// they want to the program.
208 class ModulePass : public Pass {
210 /// runOnModule - Virtual method overriden by subclasses to process the module
211 /// being operated on.
212 virtual bool runOnModule(Module &M) = 0;
214 virtual bool runPass(Module &M) { return runOnModule(M); }
215 virtual bool runPass(BasicBlock&) { return false; }
217 virtual void assignPassManager(PMStack &PMS,
218 PassManagerType T = PMT_ModulePassManager);
219 // Force out-of-line virtual method.
220 virtual ~ModulePass();
224 //===----------------------------------------------------------------------===//
225 /// ImmutablePass class - This class is used to provide information that does
226 /// not need to be run. This is useful for things like target information and
227 /// "basic" versions of AnalysisGroups.
229 class ImmutablePass : public ModulePass {
231 /// initializePass - This method may be overriden by immutable passes to allow
232 /// them to perform various initialization actions they require. This is
233 /// primarily because an ImmutablePass can "require" another ImmutablePass,
234 /// and if it does, the overloaded version of initializePass may get access to
235 /// these passes with getAnalysis<>.
237 virtual void initializePass() {}
239 /// ImmutablePasses are never run.
241 virtual bool runOnModule(Module &M) { return false; }
243 // Force out-of-line virtual method.
244 virtual ~ImmutablePass();
247 //===----------------------------------------------------------------------===//
248 /// FunctionPass class - This class is used to implement most global
249 /// optimizations. Optimizations should subclass this class if they meet the
250 /// following constraints:
252 /// 1. Optimizations are organized globally, i.e., a function at a time
253 /// 2. Optimizing a function does not cause the addition or removal of any
254 /// functions in the module
256 class FunctionPass : public Pass {
258 /// doInitialization - Virtual method overridden by subclasses to do
259 /// any necessary per-module initialization.
261 virtual bool doInitialization(Module &M) { return false; }
263 /// runOnFunction - Virtual method overriden by subclasses to do the
264 /// per-function processing of the pass.
266 virtual bool runOnFunction(Function &F) = 0;
268 /// doFinalization - Virtual method overriden by subclasses to do any post
269 /// processing needed after all passes have run.
271 virtual bool doFinalization(Module &M) { return false; }
273 /// runOnModule - On a module, we run this pass by initializing,
274 /// ronOnFunction'ing once for every function in the module, then by
277 virtual bool runOnModule(Module &M);
279 /// run - On a function, we simply initialize, run the function, then
282 bool run(Function &F);
284 virtual void assignPassManager(PMStack &PMS,
285 PassManagerType T = PMT_FunctionPassManager);
290 //===----------------------------------------------------------------------===//
291 /// BasicBlockPass class - This class is used to implement most local
292 /// optimizations. Optimizations should subclass this class if they
293 /// meet the following constraints:
294 /// 1. Optimizations are local, operating on either a basic block or
295 /// instruction at a time.
296 /// 2. Optimizations do not modify the CFG of the contained function, or any
297 /// other basic block in the function.
298 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
300 class BasicBlockPass : public Pass {
302 /// doInitialization - Virtual method overridden by subclasses to do
303 /// any necessary per-module initialization.
305 virtual bool doInitialization(Module &M) { return false; }
307 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
308 /// to do any necessary per-function initialization.
310 virtual bool doInitialization(Function &F) { return false; }
312 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
313 /// per-basicblock processing of the pass.
315 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
317 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
318 /// do any post processing needed after all passes have run.
320 virtual bool doFinalization(Function &F) { return false; }
322 /// doFinalization - Virtual method overriden by subclasses to do any post
323 /// processing needed after all passes have run.
325 virtual bool doFinalization(Module &M) { return false; }
328 // To run this pass on a function, we simply call runOnBasicBlock once for
331 bool runOnFunction(Function &F);
333 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
336 virtual bool runPass(Module &M) { return false; }
337 virtual bool runPass(BasicBlock &BB);
339 virtual void assignPassManager(PMStack &PMS,
340 PassManagerType T = PMT_BasicBlockPassManager);
344 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
345 /// using PMStack. Each Pass implements assignPassManager() to connect itself
346 /// with appropriate manager. assignPassManager() walks PMStack to find
347 /// suitable manager.
349 /// PMStack is just a wrapper around standard deque that overrides pop() and
353 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
354 iterator begin() { return S.rbegin(); }
355 iterator end() { return S.rend(); }
357 void handleLastUserOverflow();
360 inline PMDataManager *top() { return S.back(); }
362 inline bool empty() { return S.empty(); }
366 std::deque<PMDataManager *> S;
370 /// If the user specifies the -time-passes argument on an LLVM tool command line
371 /// then the value of this boolean will be true, otherwise false.
372 /// @brief This is the storage for the -time-passes option.
373 extern bool TimePassesIsEnabled;
375 } // End llvm namespace
377 // Include support files that contain important APIs commonly used by Passes,
378 // but that we want to separate out to make it easier to read the header files.
380 #include "llvm/PassSupport.h"
381 #include "llvm/PassAnalysisSupport.h"