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