Pass.h revision 8f93b7fc36dbeba428c6dd122c07fe0777baa664
1//===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source 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 effeciently 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/Streams.h" 33#include <vector> 34#include <deque> 35#include <map> 36#include <iosfwd> 37#include <typeinfo> 38#include <cassert> 39 40namespace llvm { 41 42class Value; 43class BasicBlock; 44class Function; 45class Module; 46class AnalysisUsage; 47class PassInfo; 48class ImmutablePass; 49class BasicBlockPassManager; 50class ModulePassManager; 51class PMStack; 52class AnalysisResolver; 53class PMDataManager; 54 55// AnalysisID - Use the PassInfo to identify a pass... 56typedef const PassInfo* AnalysisID; 57 58/// Different types of internal pass managers. External pass managers 59/// (PassManager and FunctionPassManager) are not represented here. 60/// Ordering of pass manager types is important here. 61enum PassManagerType { 62 PMT_Unknown = 0, 63 PMT_ModulePassManager = 1, /// MPPassManager 64 PMT_CallGraphPassManager, /// CGPassManager 65 PMT_FunctionPassManager, /// FPPassManager 66 PMT_LoopPassManager, /// LPPassManager 67 PMT_BasicBlockPassManager, /// BBPassManager 68 PMT_Last 69}; 70 71typedef enum PassManagerType PassManagerType; 72 73//===----------------------------------------------------------------------===// 74/// Pass interface - Implemented by all 'passes'. Subclass this if you are an 75/// interprocedural optimization or you do not fit into any of the more 76/// constrained passes described below. 77/// 78class Pass { 79 AnalysisResolver *Resolver; // Used to resolve analysis 80 const PassInfo *PassInfoCache; 81 82 // AnalysisImpls - This keeps track of which passes implement the interfaces 83 // that are required by the current pass (to implement getAnalysis()). 84 // 85 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls; 86 87 void operator=(const Pass&); // DO NOT IMPLEMENT 88 Pass(const Pass &); // DO NOT IMPLEMENT 89public: 90 Pass() : Resolver(0), PassInfoCache(0) {} 91 virtual ~Pass() {} // Destructor is virtual so we can be subclassed 92 93 /// getPassName - Return a nice clean name for a pass. This usually 94 /// implemented in terms of the name that is registered by one of the 95 /// Registration templates, but can be overloaded directly, and if nothing 96 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT 97 /// intelligible name for the pass. 98 /// 99 virtual const char *getPassName() const; 100 101 /// getPassInfo - Return the PassInfo data structure that corresponds to this 102 /// pass... If the pass has not been registered, this will return null. 103 /// 104 const PassInfo *getPassInfo() const; 105 106 /// runPass - Run this pass, returning true if a modification was made to the 107 /// module argument. This should be implemented by all concrete subclasses. 108 /// 109 virtual bool runPass(Module &M) { return false; } 110 virtual bool runPass(BasicBlock&) { return false; } 111 112 /// print - Print out the internal state of the pass. This is called by 113 /// Analyze to print out the contents of an analysis. Otherwise it is not 114 /// necessary to implement this method. Beware that the module pointer MAY be 115 /// null. This automatically forwards to a virtual function that does not 116 /// provide the Module* in case the analysis doesn't need it it can just be 117 /// ignored. 118 /// 119 virtual void print(std::ostream &O, const Module *M) const; 120 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 121 void dump() const; // dump - call print(std::cerr, 0); 122 123 /// Each pass is responsible for assigning a pass manager to itself. 124 /// PMS is the stack of available pass manager. 125 virtual void assignPassManager(PMStack &PMS, 126 PassManagerType T = PMT_Unknown) {} 127 /// Check if available pass managers are suitable for this pass or not. 128 virtual void preparePassManager(PMStack &PMS) {} 129 130 /// Return what kind of Pass Manager can manage this pass. 131 virtual PassManagerType getPotentialPassManagerType() const { 132 return PMT_Unknown; 133 } 134 135 // Access AnalysisResolver 136 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; } 137 inline AnalysisResolver *getResolver() { return Resolver; } 138 139 /// getAnalysisUsage - This function should be overriden by passes that need 140 /// analysis information to do their job. If a pass specifies that it uses a 141 /// particular analysis result to this function, it can then use the 142 /// getAnalysis<AnalysisType>() function, below. 143 /// 144 virtual void getAnalysisUsage(AnalysisUsage &Info) const { 145 // By default, no analysis results are used, all are invalidated. 146 } 147 148 /// releaseMemory() - This member can be implemented by a pass if it wants to 149 /// be able to release its memory when it is no longer needed. The default 150 /// behavior of passes is to hold onto memory for the entire duration of their 151 /// lifetime (which is the entire compile time). For pipelined passes, this 152 /// is not a big deal because that memory gets recycled every time the pass is 153 /// invoked on another program unit. For IP passes, it is more important to 154 /// free memory when it is unused. 155 /// 156 /// Optionally implement this function to release pass memory when it is no 157 /// longer used. 158 /// 159 virtual void releaseMemory() {} 160 161 // dumpPassStructure - Implement the -debug-passes=PassStructure option 162 virtual void dumpPassStructure(unsigned Offset = 0); 163 164 template<typename AnalysisClass> 165 static const PassInfo *getClassPassInfo() { 166 return lookupPassInfo(typeid(AnalysisClass)); 167 } 168 169 // lookupPassInfo - Return the pass info object for the specified pass class, 170 // or null if it is not known. 171 static const PassInfo *lookupPassInfo(const std::type_info &TI); 172 173 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses 174 /// to get to the analysis information that might be around that needs to be 175 /// updated. This is different than getAnalysis in that it can fail (ie the 176 /// analysis results haven't been computed), so should only be used if you 177 /// provide the capability to update an analysis that exists. This method is 178 /// often used by transformation APIs to update analysis results for a pass 179 /// automatically as the transform is performed. 180 /// 181 template<typename AnalysisType> 182 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h 183 184 /// mustPreserveAnalysisID - This method serves the same function as 185 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This 186 /// obviously cannot give you a properly typed instance of the class if you 187 /// don't have the class name available (use getAnalysisToUpdate if you do), 188 /// but it can tell you if you need to preserve the pass at least. 189 /// 190 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 191 192 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 193 /// to the analysis information that they claim to use by overriding the 194 /// getAnalysisUsage function. 195 /// 196 template<typename AnalysisType> 197 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 198 199 template<typename AnalysisType> 200 AnalysisType &getAnalysisID(const PassInfo *PI) const; 201 202}; 203 204inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 205 P.print(OS, 0); return OS; 206} 207 208//===----------------------------------------------------------------------===// 209/// ModulePass class - This class is used to implement unstructured 210/// interprocedural optimizations and analyses. ModulePasses may do anything 211/// they want to the program. 212/// 213class ModulePass : public Pass { 214public: 215 /// runOnModule - Virtual method overriden by subclasses to process the module 216 /// being operated on. 217 virtual bool runOnModule(Module &M) = 0; 218 219 virtual bool runPass(Module &M) { return runOnModule(M); } 220 virtual bool runPass(BasicBlock&) { return false; } 221 222 virtual void assignPassManager(PMStack &PMS, 223 PassManagerType T = PMT_ModulePassManager); 224 225 /// Return what kind of Pass Manager can manage this pass. 226 virtual PassManagerType getPotentialPassManagerType() const { 227 return PMT_ModulePassManager; 228 } 229 230 // Force out-of-line virtual method. 231 virtual ~ModulePass(); 232}; 233 234 235//===----------------------------------------------------------------------===// 236/// ImmutablePass class - This class is used to provide information that does 237/// not need to be run. This is useful for things like target information and 238/// "basic" versions of AnalysisGroups. 239/// 240class ImmutablePass : public ModulePass { 241public: 242 /// initializePass - This method may be overriden by immutable passes to allow 243 /// them to perform various initialization actions they require. This is 244 /// primarily because an ImmutablePass can "require" another ImmutablePass, 245 /// and if it does, the overloaded version of initializePass may get access to 246 /// these passes with getAnalysis<>. 247 /// 248 virtual void initializePass() {} 249 250 /// ImmutablePasses are never run. 251 /// 252 virtual bool runOnModule(Module &M) { return false; } 253 254 // Force out-of-line virtual method. 255 virtual ~ImmutablePass(); 256}; 257 258//===----------------------------------------------------------------------===// 259/// FunctionPass class - This class is used to implement most global 260/// optimizations. Optimizations should subclass this class if they meet the 261/// following constraints: 262/// 263/// 1. Optimizations are organized globally, i.e., a function at a time 264/// 2. Optimizing a function does not cause the addition or removal of any 265/// functions in the module 266/// 267class FunctionPass : public Pass { 268public: 269 /// doInitialization - Virtual method overridden by subclasses to do 270 /// any necessary per-module initialization. 271 /// 272 virtual bool doInitialization(Module &M) { return false; } 273 274 /// runOnFunction - Virtual method overriden by subclasses to do the 275 /// per-function processing of the pass. 276 /// 277 virtual bool runOnFunction(Function &F) = 0; 278 279 /// doFinalization - Virtual method overriden by subclasses to do any post 280 /// processing needed after all passes have run. 281 /// 282 virtual bool doFinalization(Module &M) { return false; } 283 284 /// runOnModule - On a module, we run this pass by initializing, 285 /// ronOnFunction'ing once for every function in the module, then by 286 /// finalizing. 287 /// 288 virtual bool runOnModule(Module &M); 289 290 /// run - On a function, we simply initialize, run the function, then 291 /// finalize. 292 /// 293 bool run(Function &F); 294 295 virtual void assignPassManager(PMStack &PMS, 296 PassManagerType T = PMT_FunctionPassManager); 297 298 /// Return what kind of Pass Manager can manage this pass. 299 virtual PassManagerType getPotentialPassManagerType() const { 300 return PMT_FunctionPassManager; 301 } 302}; 303 304 305 306//===----------------------------------------------------------------------===// 307/// BasicBlockPass class - This class is used to implement most local 308/// optimizations. Optimizations should subclass this class if they 309/// meet the following constraints: 310/// 1. Optimizations are local, operating on either a basic block or 311/// instruction at a time. 312/// 2. Optimizations do not modify the CFG of the contained function, or any 313/// other basic block in the function. 314/// 3. Optimizations conform to all of the constraints of FunctionPasses. 315/// 316class BasicBlockPass : public Pass { 317public: 318 /// doInitialization - Virtual method overridden by subclasses to do 319 /// any necessary per-module initialization. 320 /// 321 virtual bool doInitialization(Module &M) { return false; } 322 323 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 324 /// to do any necessary per-function initialization. 325 /// 326 virtual bool doInitialization(Function &F) { return false; } 327 328 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 329 /// per-basicblock processing of the pass. 330 /// 331 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 332 333 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 334 /// do any post processing needed after all passes have run. 335 /// 336 virtual bool doFinalization(Function &F) { return false; } 337 338 /// doFinalization - Virtual method overriden by subclasses to do any post 339 /// processing needed after all passes have run. 340 /// 341 virtual bool doFinalization(Module &M) { return false; } 342 343 344 // To run this pass on a function, we simply call runOnBasicBlock once for 345 // each function. 346 // 347 bool runOnFunction(Function &F); 348 349 /// To run directly on the basic block, we initialize, runOnBasicBlock, then 350 /// finalize. 351 /// 352 virtual bool runPass(Module &M) { return false; } 353 virtual bool runPass(BasicBlock &BB); 354 355 virtual void assignPassManager(PMStack &PMS, 356 PassManagerType T = PMT_BasicBlockPassManager); 357 358 /// Return what kind of Pass Manager can manage this pass. 359 virtual PassManagerType getPotentialPassManagerType() const { 360 return PMT_BasicBlockPassManager; 361 } 362}; 363 364/// PMStack 365/// Top level pass manager (see PasManager.cpp) maintains active Pass Managers 366/// using PMStack. Each Pass implements assignPassManager() to connect itself 367/// with appropriate manager. assignPassManager() walks PMStack to find 368/// suitable manager. 369/// 370/// PMStack is just a wrapper around standard deque that overrides pop() and 371/// push() methods. 372class PMStack { 373public: 374 typedef std::deque<PMDataManager *>::reverse_iterator iterator; 375 iterator begin() { return S.rbegin(); } 376 iterator end() { return S.rend(); } 377 378 void handleLastUserOverflow(); 379 380 void pop(); 381 inline PMDataManager *top() { return S.back(); } 382 void push(Pass *P); 383 inline bool empty() { return S.empty(); } 384 385 void dump(); 386private: 387 std::deque<PMDataManager *> S; 388}; 389 390 391/// If the user specifies the -time-passes argument on an LLVM tool command line 392/// then the value of this boolean will be true, otherwise false. 393/// @brief This is the storage for the -time-passes option. 394extern bool TimePassesIsEnabled; 395 396} // End llvm namespace 397 398// Include support files that contain important APIs commonly used by Passes, 399// but that we want to separate out to make it easier to read the header files. 400// 401#include "llvm/PassSupport.h" 402#include "llvm/PassAnalysisSupport.h" 403 404#endif 405