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) 91 : Resolver(nullptr), PassID(&pid), Kind(K) { } 92 virtual ~Pass(); 93 94 95 PassKind getPassKind() const { return Kind; } 96 97 /// getPassName - Return a nice clean name for a pass. This usually 98 /// implemented in terms of the name that is registered by one of the 99 /// Registration templates, but can be overloaded directly. 100 /// 101 virtual const char *getPassName() const; 102 103 /// getPassID - Return the PassID number that corresponds to this pass. 104 AnalysisID getPassID() const { 105 return PassID; 106 } 107 108 /// doInitialization - Virtual method overridden by subclasses to do 109 /// any necessary initialization before any pass is run. 110 /// 111 virtual bool doInitialization(Module &) { return false; } 112 113 /// doFinalization - Virtual method overriden by subclasses to do any 114 /// necessary clean up after all passes have run. 115 /// 116 virtual bool doFinalization(Module &) { return false; } 117 118 /// print - Print out the internal state of the pass. This is called by 119 /// Analyze to print out the contents of an analysis. Otherwise it is not 120 /// necessary to implement this method. Beware that the module pointer MAY be 121 /// null. This automatically forwards to a virtual function that does not 122 /// provide the Module* in case the analysis doesn't need it it can just be 123 /// ignored. 124 /// 125 virtual void print(raw_ostream &O, const Module *M) const; 126 void dump() const; // dump - Print to stderr. 127 128 /// createPrinterPass - Get a Pass appropriate to print the IR this 129 /// pass operates on (Module, Function or MachineFunction). 130 virtual Pass *createPrinterPass(raw_ostream &O, 131 const std::string &Banner) const = 0; 132 133 /// Each pass is responsible for assigning a pass manager to itself. 134 /// PMS is the stack of available pass manager. 135 virtual void assignPassManager(PMStack &, 136 PassManagerType) {} 137 /// Check if available pass managers are suitable for this pass or not. 138 virtual void preparePassManager(PMStack &); 139 140 /// Return what kind of Pass Manager can manage this pass. 141 virtual PassManagerType getPotentialPassManagerType() const; 142 143 // Access AnalysisResolver 144 void setResolver(AnalysisResolver *AR); 145 AnalysisResolver *getResolver() const { return Resolver; } 146 147 /// getAnalysisUsage - This function should be overriden by passes that need 148 /// analysis information to do their job. If a pass specifies that it uses a 149 /// particular analysis result to this function, it can then use the 150 /// getAnalysis<AnalysisType>() function, below. 151 /// 152 virtual void getAnalysisUsage(AnalysisUsage &) const; 153 154 /// releaseMemory() - This member can be implemented by a pass if it wants to 155 /// be able to release its memory when it is no longer needed. The default 156 /// behavior of passes is to hold onto memory for the entire duration of their 157 /// lifetime (which is the entire compile time). For pipelined passes, this 158 /// is not a big deal because that memory gets recycled every time the pass is 159 /// invoked on another program unit. For IP passes, it is more important to 160 /// free memory when it is unused. 161 /// 162 /// Optionally implement this function to release pass memory when it is no 163 /// longer used. 164 /// 165 virtual void releaseMemory(); 166 167 /// getAdjustedAnalysisPointer - This method is used when a pass implements 168 /// an analysis interface through multiple inheritance. If needed, it should 169 /// override this to adjust the this pointer as needed for the specified pass 170 /// info. 171 virtual void *getAdjustedAnalysisPointer(AnalysisID ID); 172 virtual ImmutablePass *getAsImmutablePass(); 173 virtual PMDataManager *getAsPMDataManager(); 174 175 /// verifyAnalysis() - This member can be implemented by a analysis pass to 176 /// check state of analysis information. 177 virtual void verifyAnalysis() const; 178 179 // dumpPassStructure - Implement the -debug-passes=PassStructure option 180 virtual void dumpPassStructure(unsigned Offset = 0); 181 182 // lookupPassInfo - Return the pass info object for the specified pass class, 183 // or null if it is not known. 184 static const PassInfo *lookupPassInfo(const void *TI); 185 186 // lookupPassInfo - Return the pass info object for the pass with the given 187 // argument string, or null if it is not known. 188 static const PassInfo *lookupPassInfo(StringRef Arg); 189 190 // createPass - Create a object for the specified pass class, 191 // or null if it is not known. 192 static Pass *createPass(AnalysisID ID); 193 194 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to 195 /// get analysis information that might be around, for example to update it. 196 /// This is different than getAnalysis in that it can fail (if the analysis 197 /// results haven't been computed), so should only be used if you can handle 198 /// the case when the analysis is not available. This method is often used by 199 /// transformation APIs to update analysis results for a pass automatically as 200 /// the transform is performed. 201 /// 202 template<typename AnalysisType> AnalysisType * 203 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h 204 205 /// mustPreserveAnalysisID - This method serves the same function as 206 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This 207 /// obviously cannot give you a properly typed instance of the class if you 208 /// don't have the class name available (use getAnalysisIfAvailable if you 209 /// do), but it can tell you if you need to preserve the pass at least. 210 /// 211 bool mustPreserveAnalysisID(char &AID) const; 212 213 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 214 /// to the analysis information that they claim to use by overriding the 215 /// getAnalysisUsage function. 216 /// 217 template<typename AnalysisType> 218 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 219 220 template<typename AnalysisType> 221 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h 222 223 template<typename AnalysisType> 224 AnalysisType &getAnalysisID(AnalysisID PI) const; 225 226 template<typename AnalysisType> 227 AnalysisType &getAnalysisID(AnalysisID PI, Function &F); 228 }; 229 230 231 //===----------------------------------------------------------------------===// 232 /// ModulePass class - This class is used to implement unstructured 233 /// interprocedural optimizations and analyses. ModulePasses may do anything 234 /// they want to the program. 235 /// 236 class ModulePass : public Pass { 237 public: 238 /// createPrinterPass - Get a module printer pass. 239 Pass *createPrinterPass(raw_ostream &O, 240 const std::string &Banner) const override; 241 242 /// runOnModule - Virtual method overriden by subclasses to process the module 243 /// being operated on. 244 virtual bool runOnModule(Module &M) = 0; 245 246 void assignPassManager(PMStack &PMS, PassManagerType T) override; 247 248 /// Return what kind of Pass Manager can manage this pass. 249 PassManagerType getPotentialPassManagerType() const override; 250 251 explicit ModulePass(char &pid) : Pass(PT_Module, pid) {} 252 // Force out-of-line virtual method. 253 virtual ~ModulePass(); 254 }; 255 256 257 //===----------------------------------------------------------------------===// 258 /// ImmutablePass class - This class is used to provide information that does 259 /// not need to be run. This is useful for things like target information and 260 /// "basic" versions of AnalysisGroups. 261 /// 262 class ImmutablePass : public ModulePass { 263 public: 264 /// initializePass - This method may be overriden by immutable passes to allow 265 /// them to perform various initialization actions they require. This is 266 /// primarily because an ImmutablePass can "require" another ImmutablePass, 267 /// and if it does, the overloaded version of initializePass may get access to 268 /// these passes with getAnalysis<>. 269 /// 270 virtual void initializePass(); 271 272 ImmutablePass *getAsImmutablePass() override { return this; } 273 274 /// ImmutablePasses are never run. 275 /// 276 bool runOnModule(Module &) override { return false; } 277 278 explicit ImmutablePass(char &pid) 279 : ModulePass(pid) {} 280 281 // Force out-of-line virtual method. 282 virtual ~ImmutablePass(); 283 }; 284 285 //===----------------------------------------------------------------------===// 286 /// FunctionPass class - This class is used to implement most global 287 /// optimizations. Optimizations should subclass this class if they meet the 288 /// following constraints: 289 /// 290 /// 1. Optimizations are organized globally, i.e., a function at a time 291 /// 2. Optimizing a function does not cause the addition or removal of any 292 /// functions in the module 293 /// 294 class FunctionPass : public Pass { 295 public: 296 explicit FunctionPass(char &pid) : Pass(PT_Function, pid) {} 297 298 /// createPrinterPass - Get a function printer pass. 299 Pass *createPrinterPass(raw_ostream &O, 300 const std::string &Banner) const override; 301 302 /// runOnFunction - Virtual method overriden by subclasses to do the 303 /// per-function processing of the pass. 304 /// 305 virtual bool runOnFunction(Function &F) = 0; 306 307 void assignPassManager(PMStack &PMS, PassManagerType T) override; 308 309 /// Return what kind of Pass Manager can manage this pass. 310 PassManagerType getPotentialPassManagerType() const override; 311 312 protected: 313 /// skipOptnoneFunction - This function has Attribute::OptimizeNone 314 /// and most transformation passes should skip it. 315 bool skipOptnoneFunction(const Function &F) const; 316 }; 317 318 319 320 //===----------------------------------------------------------------------===// 321 /// BasicBlockPass class - This class is used to implement most local 322 /// optimizations. Optimizations should subclass this class if they 323 /// meet the following constraints: 324 /// 1. Optimizations are local, operating on either a basic block or 325 /// instruction at a time. 326 /// 2. Optimizations do not modify the CFG of the contained function, or any 327 /// other basic block in the function. 328 /// 3. Optimizations conform to all of the constraints of FunctionPasses. 329 /// 330 class BasicBlockPass : public Pass { 331 public: 332 explicit BasicBlockPass(char &pid) : Pass(PT_BasicBlock, pid) {} 333 334 /// createPrinterPass - Get a basic block printer pass. 335 Pass *createPrinterPass(raw_ostream &O, 336 const std::string &Banner) const override; 337 338 using llvm::Pass::doInitialization; 339 using llvm::Pass::doFinalization; 340 341 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 342 /// to do any necessary per-function initialization. 343 /// 344 virtual bool doInitialization(Function &); 345 346 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 347 /// per-basicblock processing of the pass. 348 /// 349 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 350 351 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 352 /// do any post processing needed after all passes have run. 353 /// 354 virtual bool doFinalization(Function &); 355 356 void assignPassManager(PMStack &PMS, PassManagerType T) override; 357 358 /// Return what kind of Pass Manager can manage this pass. 359 PassManagerType getPotentialPassManagerType() const override; 360 361 protected: 362 /// skipOptnoneFunction - Containing function has Attribute::OptimizeNone 363 /// and most transformation passes should skip it. 364 bool skipOptnoneFunction(const BasicBlock &BB) const; 365 }; 366 367 /// If the user specifies the -time-passes argument on an LLVM tool command line 368 /// then the value of this boolean will be true, otherwise false. 369 /// @brief This is the storage for the -time-passes option. 370 extern bool TimePassesIsEnabled; 371 372 } // End llvm namespace 373 374 // Include support files that contain important APIs commonly used by Passes, 375 // but that we want to separate out to make it easier to read the header files. 376 // 377 #include "llvm/PassSupport.h" 378 #include "llvm/PassAnalysisSupport.h" 379 380 #endif 381
