1 //===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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/System/DataTypes.h"
47 class AnalysisResolver;
52 // AnalysisID - Use the PassInfo to identify a pass...
53 typedef const PassInfo* AnalysisID;
55 /// Different types of internal pass managers. External pass managers
56 /// (PassManager and FunctionPassManager) are not represented here.
57 /// Ordering of pass manager types is important here.
58 enum PassManagerType {
60 PMT_ModulePassManager = 1, ///< MPPassManager
61 PMT_CallGraphPassManager, ///< CGPassManager
62 PMT_FunctionPassManager, ///< FPPassManager
63 PMT_LoopPassManager, ///< LPPassManager
64 PMT_BasicBlockPassManager, ///< BBPassManager
68 // Different types of passes.
78 //===----------------------------------------------------------------------===//
79 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
80 /// interprocedural optimization or you do not fit into any of the more
81 /// constrained passes described below.
84 AnalysisResolver *Resolver; // Used to resolve analysis
87 void operator=(const Pass&); // DO NOT IMPLEMENT
88 Pass(const Pass &); // DO NOT IMPLEMENT
91 explicit Pass(PassKind K, intptr_t pid);
92 explicit Pass(PassKind K, const void *pid);
96 PassKind getPassKind() const { return Kind; }
98 /// getPassName - Return a nice clean name for a pass. This usually
99 /// implemented in terms of the name that is registered by one of the
100 /// Registration templates, but can be overloaded directly.
102 virtual const char *getPassName() const;
104 /// getPassInfo - Return the PassInfo data structure that corresponds to this
105 /// pass... If the pass has not been registered, this will return null.
107 const PassInfo *getPassInfo() const;
109 /// print - Print out the internal state of the pass. This is called by
110 /// Analyze to print out the contents of an analysis. Otherwise it is not
111 /// necessary to implement this method. Beware that the module pointer MAY be
112 /// null. This automatically forwards to a virtual function that does not
113 /// provide the Module* in case the analysis doesn't need it it can just be
116 virtual void print(raw_ostream &O, const Module *M) const;
117 void dump() const; // dump - Print to stderr.
119 /// createPrinterPass - Get a Pass appropriate to print the IR this
120 /// pass operates one (Module, Function or MachineFunction).
121 virtual Pass *createPrinterPass(raw_ostream &O,
122 const std::string &Banner) const = 0;
124 /// Each pass is responsible for assigning a pass manager to itself.
125 /// PMS is the stack of available pass manager.
126 virtual void assignPassManager(PMStack &,
127 PassManagerType = PMT_Unknown) {}
128 /// Check if available pass managers are suitable for this pass or not.
129 virtual void preparePassManager(PMStack &);
131 /// Return what kind of Pass Manager can manage this pass.
132 virtual PassManagerType getPotentialPassManagerType() const;
134 // Access AnalysisResolver
135 void setResolver(AnalysisResolver *AR);
136 AnalysisResolver *getResolver() const { return Resolver; }
138 /// getAnalysisUsage - This function should be overriden by passes that need
139 /// analysis information to do their job. If a pass specifies that it uses a
140 /// particular analysis result to this function, it can then use the
141 /// getAnalysis<AnalysisType>() function, below.
143 virtual void getAnalysisUsage(AnalysisUsage &) const;
145 /// releaseMemory() - This member can be implemented by a pass if it wants to
146 /// be able to release its memory when it is no longer needed. The default
147 /// behavior of passes is to hold onto memory for the entire duration of their
148 /// lifetime (which is the entire compile time). For pipelined passes, this
149 /// is not a big deal because that memory gets recycled every time the pass is
150 /// invoked on another program unit. For IP passes, it is more important to
151 /// free memory when it is unused.
153 /// Optionally implement this function to release pass memory when it is no
156 virtual void releaseMemory();
158 /// getAdjustedAnalysisPointer - This method is used when a pass implements
159 /// an analysis interface through multiple inheritance. If needed, it should
160 /// override this to adjust the this pointer as needed for the specified pass
162 virtual void *getAdjustedAnalysisPointer(const PassInfo *);
163 virtual ImmutablePass *getAsImmutablePass();
164 virtual PMDataManager *getAsPMDataManager();
166 /// verifyAnalysis() - This member can be implemented by a analysis pass to
167 /// check state of analysis information.
168 virtual void verifyAnalysis() const;
170 // dumpPassStructure - Implement the -debug-passes=PassStructure option
171 virtual void dumpPassStructure(unsigned Offset = 0);
173 template<typename AnalysisClass>
174 static const PassInfo *getClassPassInfo() {
175 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
178 // lookupPassInfo - Return the pass info object for the specified pass class,
179 // or null if it is not known.
180 static const PassInfo *lookupPassInfo(intptr_t TI);
182 // lookupPassInfo - Return the pass info object for the pass with the given
183 // argument string, or null if it is not known.
184 static const PassInfo *lookupPassInfo(StringRef Arg);
186 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
187 /// get analysis information that might be around, for example to update it.
188 /// This is different than getAnalysis in that it can fail (if the analysis
189 /// results haven't been computed), so should only be used if you can handle
190 /// the case when the analysis is not available. This method is often used by
191 /// transformation APIs to update analysis results for a pass automatically as
192 /// the transform is performed.
194 template<typename AnalysisType> AnalysisType *
195 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
197 /// mustPreserveAnalysisID - This method serves the same function as
198 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
199 /// obviously cannot give you a properly typed instance of the class if you
200 /// don't have the class name available (use getAnalysisIfAvailable if you
201 /// do), but it can tell you if you need to preserve the pass at least.
203 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
205 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
206 /// to the analysis information that they claim to use by overriding the
207 /// getAnalysisUsage function.
209 template<typename AnalysisType>
210 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
212 template<typename AnalysisType>
213 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h
215 template<typename AnalysisType>
216 AnalysisType &getAnalysisID(const PassInfo *PI) const;
218 template<typename AnalysisType>
219 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
223 //===----------------------------------------------------------------------===//
224 /// ModulePass class - This class is used to implement unstructured
225 /// interprocedural optimizations and analyses. ModulePasses may do anything
226 /// they want to the program.
228 class ModulePass : public Pass {
230 /// createPrinterPass - Get a module printer pass.
231 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
233 /// runOnModule - Virtual method overriden by subclasses to process the module
234 /// being operated on.
235 virtual bool runOnModule(Module &M) = 0;
237 virtual void assignPassManager(PMStack &PMS,
238 PassManagerType T = PMT_ModulePassManager);
240 /// Return what kind of Pass Manager can manage this pass.
241 virtual PassManagerType getPotentialPassManagerType() const;
243 explicit ModulePass(intptr_t pid) : Pass(PT_Module, pid) {}
244 explicit ModulePass(const void *pid) : Pass(PT_Module, pid) {}
245 // Force out-of-line virtual method.
246 virtual ~ModulePass();
250 //===----------------------------------------------------------------------===//
251 /// ImmutablePass class - This class is used to provide information that does
252 /// not need to be run. This is useful for things like target information and
253 /// "basic" versions of AnalysisGroups.
255 class ImmutablePass : public ModulePass {
257 /// initializePass - This method may be overriden by immutable passes to allow
258 /// them to perform various initialization actions they require. This is
259 /// primarily because an ImmutablePass can "require" another ImmutablePass,
260 /// and if it does, the overloaded version of initializePass may get access to
261 /// these passes with getAnalysis<>.
263 virtual void initializePass();
265 virtual ImmutablePass *getAsImmutablePass() { return this; }
267 /// ImmutablePasses are never run.
269 bool runOnModule(Module &) { return false; }
271 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
272 explicit ImmutablePass(const void *pid)
275 // Force out-of-line virtual method.
276 virtual ~ImmutablePass();
279 //===----------------------------------------------------------------------===//
280 /// FunctionPass class - This class is used to implement most global
281 /// optimizations. Optimizations should subclass this class if they meet the
282 /// following constraints:
284 /// 1. Optimizations are organized globally, i.e., a function at a time
285 /// 2. Optimizing a function does not cause the addition or removal of any
286 /// functions in the module
288 class FunctionPass : public Pass {
290 explicit FunctionPass(intptr_t pid) : Pass(PT_Function, pid) {}
291 explicit FunctionPass(const void *pid) : Pass(PT_Function, pid) {}
293 /// createPrinterPass - Get a function printer pass.
294 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
296 /// doInitialization - Virtual method overridden by subclasses to do
297 /// any necessary per-module initialization.
299 virtual bool doInitialization(Module &);
301 /// runOnFunction - Virtual method overriden by subclasses to do the
302 /// per-function processing of the pass.
304 virtual bool runOnFunction(Function &F) = 0;
306 /// doFinalization - Virtual method overriden by subclasses to do any post
307 /// processing needed after all passes have run.
309 virtual bool doFinalization(Module &);
311 /// runOnModule - On a module, we run this pass by initializing,
312 /// ronOnFunction'ing once for every function in the module, then by
315 virtual bool runOnModule(Module &M);
317 /// run - On a function, we simply initialize, run the function, then
320 bool run(Function &F);
322 virtual void assignPassManager(PMStack &PMS,
323 PassManagerType T = PMT_FunctionPassManager);
325 /// Return what kind of Pass Manager can manage this pass.
326 virtual PassManagerType getPotentialPassManagerType() const;
331 //===----------------------------------------------------------------------===//
332 /// BasicBlockPass class - This class is used to implement most local
333 /// optimizations. Optimizations should subclass this class if they
334 /// meet the following constraints:
335 /// 1. Optimizations are local, operating on either a basic block or
336 /// instruction at a time.
337 /// 2. Optimizations do not modify the CFG of the contained function, or any
338 /// other basic block in the function.
339 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
341 class BasicBlockPass : public Pass {
343 explicit BasicBlockPass(intptr_t pid) : Pass(PT_BasicBlock, pid) {}
344 explicit BasicBlockPass(const void *pid) : Pass(PT_BasicBlock, pid) {}
346 /// createPrinterPass - Get a function printer pass.
347 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
349 /// doInitialization - Virtual method overridden by subclasses to do
350 /// any necessary per-module initialization.
352 virtual bool doInitialization(Module &);
354 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
355 /// to do any necessary per-function initialization.
357 virtual bool doInitialization(Function &);
359 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
360 /// per-basicblock processing of the pass.
362 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
364 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
365 /// do any post processing needed after all passes have run.
367 virtual bool doFinalization(Function &);
369 /// doFinalization - Virtual method overriden by subclasses to do any post
370 /// processing needed after all passes have run.
372 virtual bool doFinalization(Module &);
375 // To run this pass on a function, we simply call runOnBasicBlock once for
378 bool runOnFunction(Function &F);
380 virtual void assignPassManager(PMStack &PMS,
381 PassManagerType T = PMT_BasicBlockPassManager);
383 /// Return what kind of Pass Manager can manage this pass.
384 virtual PassManagerType getPotentialPassManagerType() const;
387 /// If the user specifies the -time-passes argument on an LLVM tool command line
388 /// then the value of this boolean will be true, otherwise false.
389 /// @brief This is the storage for the -time-passes option.
390 extern bool TimePassesIsEnabled;
392 } // End llvm namespace
394 // Include support files that contain important APIs commonly used by Passes,
395 // but that we want to separate out to make it easier to read the header files.
397 #include "llvm/PassSupport.h"
398 #include "llvm/PassAnalysisSupport.h"