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 efficiently 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/Compiler.h"
44 class AnalysisResolver;
49 // AnalysisID - Use the PassInfo to identify a pass...
50 typedef const void* AnalysisID;
52 /// Different types of internal pass managers. External pass managers
53 /// (PassManager and FunctionPassManager) are not represented here.
54 /// Ordering of pass manager types is important here.
55 enum PassManagerType {
57 PMT_ModulePassManager = 1, ///< MPPassManager
58 PMT_CallGraphPassManager, ///< CGPassManager
59 PMT_FunctionPassManager, ///< FPPassManager
60 PMT_LoopPassManager, ///< LPPassManager
61 PMT_RegionPassManager, ///< RGPassManager
62 PMT_BasicBlockPassManager, ///< BBPassManager
66 // Different types of passes.
77 //===----------------------------------------------------------------------===//
78 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
79 /// interprocedural optimization or you do not fit into any of the more
80 /// constrained passes described below.
83 AnalysisResolver *Resolver; // Used to resolve analysis
86 void operator=(const Pass&) LLVM_DELETED_FUNCTION;
87 Pass(const Pass &) LLVM_DELETED_FUNCTION;
90 explicit Pass(PassKind K, char &pid) : Resolver(0), PassID(&pid), Kind(K) { }
94 PassKind getPassKind() const { return Kind; }
96 /// getPassName - Return a nice clean name for a pass. This usually
97 /// implemented in terms of the name that is registered by one of the
98 /// Registration templates, but can be overloaded directly.
100 virtual const char *getPassName() const;
102 /// getPassID - Return the PassID number that corresponds to this pass.
103 AnalysisID getPassID() const {
107 /// print - Print out the internal state of the pass. This is called by
108 /// Analyze to print out the contents of an analysis. Otherwise it is not
109 /// necessary to implement this method. Beware that the module pointer MAY be
110 /// null. This automatically forwards to a virtual function that does not
111 /// provide the Module* in case the analysis doesn't need it it can just be
114 virtual void print(raw_ostream &O, const Module *M) const;
115 void dump() const; // dump - Print to stderr.
117 /// createPrinterPass - Get a Pass appropriate to print the IR this
118 /// pass operates on (Module, Function or MachineFunction).
119 virtual Pass *createPrinterPass(raw_ostream &O,
120 const std::string &Banner) const = 0;
122 /// Each pass is responsible for assigning a pass manager to itself.
123 /// PMS is the stack of available pass manager.
124 virtual void assignPassManager(PMStack &,
126 /// Check if available pass managers are suitable for this pass or not.
127 virtual void preparePassManager(PMStack &);
129 /// Return what kind of Pass Manager can manage this pass.
130 virtual PassManagerType getPotentialPassManagerType() const;
132 // Access AnalysisResolver
133 void setResolver(AnalysisResolver *AR);
134 AnalysisResolver *getResolver() const { return Resolver; }
136 /// getAnalysisUsage - This function should be overriden by passes that need
137 /// analysis information to do their job. If a pass specifies that it uses a
138 /// particular analysis result to this function, it can then use the
139 /// getAnalysis<AnalysisType>() function, below.
141 virtual void getAnalysisUsage(AnalysisUsage &) const;
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 /// getAdjustedAnalysisPointer - This method is used when a pass implements
157 /// an analysis interface through multiple inheritance. If needed, it should
158 /// override this to adjust the this pointer as needed for the specified pass
160 virtual void *getAdjustedAnalysisPointer(AnalysisID ID);
161 virtual ImmutablePass *getAsImmutablePass();
162 virtual PMDataManager *getAsPMDataManager();
164 /// verifyAnalysis() - This member can be implemented by a analysis pass to
165 /// check state of analysis information.
166 virtual void verifyAnalysis() const;
168 // dumpPassStructure - Implement the -debug-passes=PassStructure option
169 virtual void dumpPassStructure(unsigned Offset = 0);
171 // lookupPassInfo - Return the pass info object for the specified pass class,
172 // or null if it is not known.
173 static const PassInfo *lookupPassInfo(const void *TI);
175 // lookupPassInfo - Return the pass info object for the pass with the given
176 // argument string, or null if it is not known.
177 static const PassInfo *lookupPassInfo(StringRef Arg);
179 // createPass - Create a object for the specified pass class,
180 // or null if it is not known.
181 static Pass *createPass(AnalysisID ID);
183 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
184 /// get analysis information that might be around, for example to update it.
185 /// This is different than getAnalysis in that it can fail (if the analysis
186 /// results haven't been computed), so should only be used if you can handle
187 /// the case when the analysis is not available. This method is often used by
188 /// transformation APIs to update analysis results for a pass automatically as
189 /// the transform is performed.
191 template<typename AnalysisType> AnalysisType *
192 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
194 /// mustPreserveAnalysisID - This method serves the same function as
195 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
196 /// obviously cannot give you a properly typed instance of the class if you
197 /// don't have the class name available (use getAnalysisIfAvailable if you
198 /// do), but it can tell you if you need to preserve the pass at least.
200 bool mustPreserveAnalysisID(char &AID) const;
202 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
203 /// to the analysis information that they claim to use by overriding the
204 /// getAnalysisUsage function.
206 template<typename AnalysisType>
207 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
209 template<typename AnalysisType>
210 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h
212 template<typename AnalysisType>
213 AnalysisType &getAnalysisID(AnalysisID PI) const;
215 template<typename AnalysisType>
216 AnalysisType &getAnalysisID(AnalysisID PI, Function &F);
220 //===----------------------------------------------------------------------===//
221 /// ModulePass class - This class is used to implement unstructured
222 /// interprocedural optimizations and analyses. ModulePasses may do anything
223 /// they want to the program.
225 class ModulePass : public Pass {
227 /// createPrinterPass - Get a module printer pass.
228 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
230 /// doInitialization - Virtual method overridden by subclasses to do
231 /// any necessary initialization.
233 virtual bool doInitialization(void) { return false; }
235 /// runOnModule - Virtual method overriden by subclasses to process the module
236 /// being operated on.
237 virtual bool runOnModule(Module &M) = 0;
239 /// doFinalization - Virtual method overriden by subclasses to do any post
240 /// processing needed after all passes have run.
242 virtual bool doFinalization(void) { return false; }
244 virtual void assignPassManager(PMStack &PMS,
247 /// Return what kind of Pass Manager can manage this pass.
248 virtual PassManagerType getPotentialPassManagerType() const;
250 explicit ModulePass(char &pid) : Pass(PT_Module, pid) {}
251 // Force out-of-line virtual method.
252 virtual ~ModulePass();
256 //===----------------------------------------------------------------------===//
257 /// ImmutablePass class - This class is used to provide information that does
258 /// not need to be run. This is useful for things like target information and
259 /// "basic" versions of AnalysisGroups.
261 class ImmutablePass : public ModulePass {
263 /// initializePass - This method may be overriden by immutable passes to allow
264 /// them to perform various initialization actions they require. This is
265 /// primarily because an ImmutablePass can "require" another ImmutablePass,
266 /// and if it does, the overloaded version of initializePass may get access to
267 /// these passes with getAnalysis<>.
269 virtual void initializePass();
271 virtual ImmutablePass *getAsImmutablePass() { return this; }
273 /// ImmutablePasses are never run.
275 bool runOnModule(Module &) { return false; }
277 explicit ImmutablePass(char &pid)
280 // Force out-of-line virtual method.
281 virtual ~ImmutablePass();
284 //===----------------------------------------------------------------------===//
285 /// FunctionPass class - This class is used to implement most global
286 /// optimizations. Optimizations should subclass this class if they meet the
287 /// following constraints:
289 /// 1. Optimizations are organized globally, i.e., a function at a time
290 /// 2. Optimizing a function does not cause the addition or removal of any
291 /// functions in the module
293 class FunctionPass : public Pass {
295 explicit FunctionPass(char &pid) : Pass(PT_Function, pid) {}
297 /// createPrinterPass - Get a function printer pass.
298 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
300 /// doInitialization - Virtual method overridden by subclasses to do
301 /// any necessary per-module initialization.
303 virtual bool doInitialization(Module &);
305 /// runOnFunction - Virtual method overriden by subclasses to do the
306 /// per-function processing of the pass.
308 virtual bool runOnFunction(Function &F) = 0;
310 /// doFinalization - Virtual method overriden by subclasses to do any post
311 /// processing needed after all passes have run.
313 virtual bool doFinalization(Module &);
315 virtual void assignPassManager(PMStack &PMS,
318 /// Return what kind of Pass Manager can manage this pass.
319 virtual PassManagerType getPotentialPassManagerType() const;
324 //===----------------------------------------------------------------------===//
325 /// BasicBlockPass class - This class is used to implement most local
326 /// optimizations. Optimizations should subclass this class if they
327 /// meet the following constraints:
328 /// 1. Optimizations are local, operating on either a basic block or
329 /// instruction at a time.
330 /// 2. Optimizations do not modify the CFG of the contained function, or any
331 /// other basic block in the function.
332 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
334 class BasicBlockPass : public Pass {
336 explicit BasicBlockPass(char &pid) : Pass(PT_BasicBlock, pid) {}
338 /// createPrinterPass - Get a basic block printer pass.
339 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
341 /// doInitialization - Virtual method overridden by subclasses to do
342 /// any necessary per-module initialization.
344 virtual bool doInitialization(Module &);
346 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
347 /// to do any necessary per-function initialization.
349 virtual bool doInitialization(Function &);
351 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
352 /// per-basicblock processing of the pass.
354 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
356 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
357 /// do any post processing needed after all passes have run.
359 virtual bool doFinalization(Function &);
361 /// doFinalization - Virtual method overriden by subclasses to do any post
362 /// processing needed after all passes have run.
364 virtual bool doFinalization(Module &);
366 virtual void assignPassManager(PMStack &PMS,
369 /// Return what kind of Pass Manager can manage this pass.
370 virtual PassManagerType getPotentialPassManagerType() const;
373 /// If the user specifies the -time-passes argument on an LLVM tool command line
374 /// then the value of this boolean will be true, otherwise false.
375 /// @brief This is the storage for the -time-passes option.
376 extern bool TimePassesIsEnabled;
378 } // End llvm namespace
380 // Include support files that contain important APIs commonly used by Passes,
381 // but that we want to separate out to make it easier to read the header files.
383 #include "llvm/PassSupport.h"
384 #include "llvm/PassAnalysisSupport.h"