1 //===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines a base class that indicates that a specified class is a 11 // transformation pass implementation. 12 // 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. 17 // 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. 22 // 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. 26 // 27 //===----------------------------------------------------------------------===// 28 29 #ifndef LLVM_PASS_H 30 #define LLVM_PASS_H 31 32 #include <string> 33 34 namespace llvm { 35 36 class BasicBlock; 37 class Function; 38 class Module; 39 class AnalysisUsage; 40 class PassInfo; 41 class ImmutablePass; 42 class PMStack; 43 class AnalysisResolver; 44 class PMDataManager; 45 class raw_ostream; 46 class StringRef; 47 48 // AnalysisID - Use the PassInfo to identify a pass... 49 typedef const void* AnalysisID; 50 51 /// Different types of internal pass managers. External pass managers 52 /// (PassManager and FunctionPassManager) are not represented here. 53 /// Ordering of pass manager types is important here. 54 enum PassManagerType { 55 PMT_Unknown = 0, 56 PMT_ModulePassManager = 1, ///< MPPassManager 57 PMT_CallGraphPassManager, ///< CGPassManager 58 PMT_FunctionPassManager, ///< FPPassManager 59 PMT_LoopPassManager, ///< LPPassManager 60 PMT_RegionPassManager, ///< RGPassManager 61 PMT_BasicBlockPassManager, ///< BBPassManager 62 PMT_Last 63 }; 64 65 // Different types of passes. 66 enum PassKind { 67 PT_BasicBlock, 68 PT_Region, 69 PT_Loop, 70 PT_Function, 71 PT_CallGraphSCC, 72 PT_Module, 73 PT_PassManager 74 }; 75 76 //===----------------------------------------------------------------------===// 77 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an 78 /// interprocedural optimization or you do not fit into any of the more 79 /// constrained passes described below. 80 /// 81 class Pass { 82 AnalysisResolver *Resolver; // Used to resolve analysis 83 const void *PassID; 84 PassKind Kind; 85 void operator=(const Pass&); // DO NOT IMPLEMENT 86 Pass(const Pass &); // DO NOT IMPLEMENT 87 88 public: 89 explicit Pass(PassKind K, char &pid); 90 virtual ~Pass(); 91 92 93 PassKind getPassKind() const { return Kind; } 94 95 /// getPassName - Return a nice clean name for a pass. This usually 96 /// implemented in terms of the name that is registered by one of the 97 /// Registration templates, but can be overloaded directly. 98 /// 99 virtual const char *getPassName() const; 100 101 /// getPassID - Return the PassID number that corresponds to this pass. 102 virtual AnalysisID getPassID() const { 103 return PassID; 104 } 105 106 /// print - Print out the internal state of the pass. This is called by 107 /// Analyze to print out the contents of an analysis. Otherwise it is not 108 /// necessary to implement this method. Beware that the module pointer MAY be 109 /// null. This automatically forwards to a virtual function that does not 110 /// provide the Module* in case the analysis doesn't need it it can just be 111 /// ignored. 112 /// 113 virtual void print(raw_ostream &O, const Module *M) const; 114 void dump() const; // dump - Print to stderr. 115 116 /// createPrinterPass - Get a Pass appropriate to print the IR this 117 /// pass operates on (Module, Function or MachineFunction). 118 virtual Pass *createPrinterPass(raw_ostream &O, 119 const std::string &Banner) const = 0; 120 121 /// Each pass is responsible for assigning a pass manager to itself. 122 /// PMS is the stack of available pass manager. 123 virtual void assignPassManager(PMStack &, 124 PassManagerType) {} 125 /// Check if available pass managers are suitable for this pass or not. 126 virtual void preparePassManager(PMStack &); 127 128 /// Return what kind of Pass Manager can manage this pass. 129 virtual PassManagerType getPotentialPassManagerType() const; 130 131 // Access AnalysisResolver 132 void setResolver(AnalysisResolver *AR); 133 AnalysisResolver *getResolver() const { return Resolver; } 134 135 /// getAnalysisUsage - This function should be overriden by passes that need 136 /// analysis information to do their job. If a pass specifies that it uses a 137 /// particular analysis result to this function, it can then use the 138 /// getAnalysis<AnalysisType>() function, below. 139 /// 140 virtual void getAnalysisUsage(AnalysisUsage &) const; 141 142 /// releaseMemory() - This member can be implemented by a pass if it wants to 143 /// be able to release its memory when it is no longer needed. The default 144 /// behavior of passes is to hold onto memory for the entire duration of their 145 /// lifetime (which is the entire compile time). For pipelined passes, this 146 /// is not a big deal because that memory gets recycled every time the pass is 147 /// invoked on another program unit. For IP passes, it is more important to 148 /// free memory when it is unused. 149 /// 150 /// Optionally implement this function to release pass memory when it is no 151 /// longer used. 152 /// 153 virtual void releaseMemory(); 154 155 /// getAdjustedAnalysisPointer - This method is used when a pass implements 156 /// an analysis interface through multiple inheritance. If needed, it should 157 /// override this to adjust the this pointer as needed for the specified pass 158 /// info. 159 virtual void *getAdjustedAnalysisPointer(AnalysisID ID); 160 virtual ImmutablePass *getAsImmutablePass(); 161 virtual PMDataManager *getAsPMDataManager(); 162 163 /// verifyAnalysis() - This member can be implemented by a analysis pass to 164 /// check state of analysis information. 165 virtual void verifyAnalysis() const; 166 167 // dumpPassStructure - Implement the -debug-passes=PassStructure option 168 virtual void dumpPassStructure(unsigned Offset = 0); 169 170 // lookupPassInfo - Return the pass info object for the specified pass class, 171 // or null if it is not known. 172 static const PassInfo *lookupPassInfo(const void *TI); 173 174 // lookupPassInfo - Return the pass info object for the pass with the given 175 // argument string, or null if it is not known. 176 static const PassInfo *lookupPassInfo(StringRef Arg); 177 178 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to 179 /// get analysis information that might be around, for example to update it. 180 /// This is different than getAnalysis in that it can fail (if the analysis 181 /// results haven't been computed), so should only be used if you can handle 182 /// the case when the analysis is not available. This method is often used by 183 /// transformation APIs to update analysis results for a pass automatically as 184 /// the transform is performed. 185 /// 186 template<typename AnalysisType> AnalysisType * 187 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h 188 189 /// mustPreserveAnalysisID - This method serves the same function as 190 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This 191 /// obviously cannot give you a properly typed instance of the class if you 192 /// don't have the class name available (use getAnalysisIfAvailable if you 193 /// do), but it can tell you if you need to preserve the pass at least. 194 /// 195 bool mustPreserveAnalysisID(char &AID) const; 196 197 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 198 /// to the analysis information that they claim to use by overriding the 199 /// getAnalysisUsage function. 200 /// 201 template<typename AnalysisType> 202 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 203 204 template<typename AnalysisType> 205 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h 206 207 template<typename AnalysisType> 208 AnalysisType &getAnalysisID(AnalysisID PI) const; 209 210 template<typename AnalysisType> 211 AnalysisType &getAnalysisID(AnalysisID PI, Function &F); 212 }; 213 214 215 //===----------------------------------------------------------------------===// 216 /// ModulePass class - This class is used to implement unstructured 217 /// interprocedural optimizations and analyses. ModulePasses may do anything 218 /// they want to the program. 219 /// 220 class ModulePass : public Pass { 221 public: 222 /// createPrinterPass - Get a module printer pass. 223 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const; 224 225 /// runOnModule - Virtual method overriden by subclasses to process the module 226 /// being operated on. 227 virtual bool runOnModule(Module &M) = 0; 228 229 virtual void assignPassManager(PMStack &PMS, 230 PassManagerType T); 231 232 /// Return what kind of Pass Manager can manage this pass. 233 virtual PassManagerType getPotentialPassManagerType() const; 234 235 explicit ModulePass(char &pid) : Pass(PT_Module, pid) {} 236 // Force out-of-line virtual method. 237 virtual ~ModulePass(); 238 }; 239 240 241 //===----------------------------------------------------------------------===// 242 /// ImmutablePass class - This class is used to provide information that does 243 /// not need to be run. This is useful for things like target information and 244 /// "basic" versions of AnalysisGroups. 245 /// 246 class ImmutablePass : public ModulePass { 247 public: 248 /// initializePass - This method may be overriden by immutable passes to allow 249 /// them to perform various initialization actions they require. This is 250 /// primarily because an ImmutablePass can "require" another ImmutablePass, 251 /// and if it does, the overloaded version of initializePass may get access to 252 /// these passes with getAnalysis<>. 253 /// 254 virtual void initializePass(); 255 256 virtual ImmutablePass *getAsImmutablePass() { return this; } 257 258 /// ImmutablePasses are never run. 259 /// 260 bool runOnModule(Module &) { return false; } 261 262 explicit ImmutablePass(char &pid) 263 : ModulePass(pid) {} 264 265 // Force out-of-line virtual method. 266 virtual ~ImmutablePass(); 267 }; 268 269 //===----------------------------------------------------------------------===// 270 /// FunctionPass class - This class is used to implement most global 271 /// optimizations. Optimizations should subclass this class if they meet the 272 /// following constraints: 273 /// 274 /// 1. Optimizations are organized globally, i.e., a function at a time 275 /// 2. Optimizing a function does not cause the addition or removal of any 276 /// functions in the module 277 /// 278 class FunctionPass : public Pass { 279 public: 280 explicit FunctionPass(char &pid) : Pass(PT_Function, pid) {} 281 282 /// createPrinterPass - Get a function printer pass. 283 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const; 284 285 /// doInitialization - Virtual method overridden by subclasses to do 286 /// any necessary per-module initialization. 287 /// 288 virtual bool doInitialization(Module &); 289 290 /// runOnFunction - Virtual method overriden by subclasses to do the 291 /// per-function processing of the pass. 292 /// 293 virtual bool runOnFunction(Function &F) = 0; 294 295 /// doFinalization - Virtual method overriden by subclasses to do any post 296 /// processing needed after all passes have run. 297 /// 298 virtual bool doFinalization(Module &); 299 300 virtual void assignPassManager(PMStack &PMS, 301 PassManagerType T); 302 303 /// Return what kind of Pass Manager can manage this pass. 304 virtual PassManagerType getPotentialPassManagerType() const; 305 }; 306 307 308 309 //===----------------------------------------------------------------------===// 310 /// BasicBlockPass class - This class is used to implement most local 311 /// optimizations. Optimizations should subclass this class if they 312 /// meet the following constraints: 313 /// 1. Optimizations are local, operating on either a basic block or 314 /// instruction at a time. 315 /// 2. Optimizations do not modify the CFG of the contained function, or any 316 /// other basic block in the function. 317 /// 3. Optimizations conform to all of the constraints of FunctionPasses. 318 /// 319 class BasicBlockPass : public Pass { 320 public: 321 explicit BasicBlockPass(char &pid) : Pass(PT_BasicBlock, pid) {} 322 323 /// createPrinterPass - Get a basic block printer pass. 324 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const; 325 326 /// doInitialization - Virtual method overridden by subclasses to do 327 /// any necessary per-module initialization. 328 /// 329 virtual bool doInitialization(Module &); 330 331 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 332 /// to do any necessary per-function initialization. 333 /// 334 virtual bool doInitialization(Function &); 335 336 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 337 /// per-basicblock processing of the pass. 338 /// 339 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 340 341 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 342 /// do any post processing needed after all passes have run. 343 /// 344 virtual bool doFinalization(Function &); 345 346 /// doFinalization - Virtual method overriden by subclasses to do any post 347 /// processing needed after all passes have run. 348 /// 349 virtual bool doFinalization(Module &); 350 351 virtual void assignPassManager(PMStack &PMS, 352 PassManagerType T); 353 354 /// Return what kind of Pass Manager can manage this pass. 355 virtual PassManagerType getPotentialPassManagerType() const; 356 }; 357 358 /// If the user specifies the -time-passes argument on an LLVM tool command line 359 /// then the value of this boolean will be true, otherwise false. 360 /// @brief This is the storage for the -time-passes option. 361 extern bool TimePassesIsEnabled; 362 363 } // End llvm namespace 364 365 // Include support files that contain important APIs commonly used by Passes, 366 // but that we want to separate out to make it easier to read the header files. 367 // 368 #include "llvm/PassSupport.h" 369 #include "llvm/PassAnalysisSupport.h" 370 371 #endif 372
