Pass.h revision 6e21ff0b0a8e4f0878431afa5628bb1c2db0b8e1
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(); 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 &getAnalysis(Function &F); // Defined in PassanalysisSupport.h 201 202 template<typename AnalysisType> 203 AnalysisType &getAnalysisID(const PassInfo *PI) const; 204 205 template<typename AnalysisType> 206 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 207}; 208 209inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 210 P.print(OS, 0); return OS; 211} 212 213//===----------------------------------------------------------------------===// 214/// ModulePass class - This class is used to implement unstructured 215/// interprocedural optimizations and analyses. ModulePasses may do anything 216/// they want to the program. 217/// 218class ModulePass : public Pass { 219public: 220 /// runOnModule - Virtual method overriden by subclasses to process the module 221 /// being operated on. 222 virtual bool runOnModule(Module &M) = 0; 223 224 virtual bool runPass(Module &M) { return runOnModule(M); } 225 virtual bool runPass(BasicBlock&) { return false; } 226 227 virtual void assignPassManager(PMStack &PMS, 228 PassManagerType T = PMT_ModulePassManager); 229 230 /// Return what kind of Pass Manager can manage this pass. 231 virtual PassManagerType getPotentialPassManagerType() const { 232 return PMT_ModulePassManager; 233 } 234 235 // Force out-of-line virtual method. 236 virtual ~ModulePass(); 237}; 238 239 240//===----------------------------------------------------------------------===// 241/// ImmutablePass class - This class is used to provide information that does 242/// not need to be run. This is useful for things like target information and 243/// "basic" versions of AnalysisGroups. 244/// 245class ImmutablePass : public ModulePass { 246public: 247 /// initializePass - This method may be overriden by immutable passes to allow 248 /// them to perform various initialization actions they require. This is 249 /// primarily because an ImmutablePass can "require" another ImmutablePass, 250 /// and if it does, the overloaded version of initializePass may get access to 251 /// these passes with getAnalysis<>. 252 /// 253 virtual void initializePass() {} 254 255 /// ImmutablePasses are never run. 256 /// 257 virtual bool runOnModule(Module &M) { return false; } 258 259 // Force out-of-line virtual method. 260 virtual ~ImmutablePass(); 261}; 262 263//===----------------------------------------------------------------------===// 264/// FunctionPass class - This class is used to implement most global 265/// optimizations. Optimizations should subclass this class if they meet the 266/// following constraints: 267/// 268/// 1. Optimizations are organized globally, i.e., a function at a time 269/// 2. Optimizing a function does not cause the addition or removal of any 270/// functions in the module 271/// 272class FunctionPass : public Pass { 273public: 274 /// doInitialization - Virtual method overridden by subclasses to do 275 /// any necessary per-module initialization. 276 /// 277 virtual bool doInitialization(Module &M) { return false; } 278 279 /// runOnFunction - Virtual method overriden by subclasses to do the 280 /// per-function processing of the pass. 281 /// 282 virtual bool runOnFunction(Function &F) = 0; 283 284 /// doFinalization - Virtual method overriden by subclasses to do any post 285 /// processing needed after all passes have run. 286 /// 287 virtual bool doFinalization(Module &M) { return false; } 288 289 /// runOnModule - On a module, we run this pass by initializing, 290 /// ronOnFunction'ing once for every function in the module, then by 291 /// finalizing. 292 /// 293 virtual bool runOnModule(Module &M); 294 295 /// run - On a function, we simply initialize, run the function, then 296 /// finalize. 297 /// 298 bool run(Function &F); 299 300 virtual void assignPassManager(PMStack &PMS, 301 PassManagerType T = PMT_FunctionPassManager); 302 303 /// Return what kind of Pass Manager can manage this pass. 304 virtual PassManagerType getPotentialPassManagerType() const { 305 return PMT_FunctionPassManager; 306 } 307}; 308 309 310 311//===----------------------------------------------------------------------===// 312/// BasicBlockPass class - This class is used to implement most local 313/// optimizations. Optimizations should subclass this class if they 314/// meet the following constraints: 315/// 1. Optimizations are local, operating on either a basic block or 316/// instruction at a time. 317/// 2. Optimizations do not modify the CFG of the contained function, or any 318/// other basic block in the function. 319/// 3. Optimizations conform to all of the constraints of FunctionPasses. 320/// 321class BasicBlockPass : public Pass { 322public: 323 /// doInitialization - Virtual method overridden by subclasses to do 324 /// any necessary per-module initialization. 325 /// 326 virtual bool doInitialization(Module &M) { return false; } 327 328 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 329 /// to do any necessary per-function initialization. 330 /// 331 virtual bool doInitialization(Function &F) { return false; } 332 333 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 334 /// per-basicblock processing of the pass. 335 /// 336 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 337 338 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 339 /// do any post processing needed after all passes have run. 340 /// 341 virtual bool doFinalization(Function &F) { return false; } 342 343 /// doFinalization - Virtual method overriden by subclasses to do any post 344 /// processing needed after all passes have run. 345 /// 346 virtual bool doFinalization(Module &M) { return false; } 347 348 349 // To run this pass on a function, we simply call runOnBasicBlock once for 350 // each function. 351 // 352 bool runOnFunction(Function &F); 353 354 /// To run directly on the basic block, we initialize, runOnBasicBlock, then 355 /// finalize. 356 /// 357 virtual bool runPass(Module &M) { return false; } 358 virtual bool runPass(BasicBlock &BB); 359 360 virtual void assignPassManager(PMStack &PMS, 361 PassManagerType T = PMT_BasicBlockPassManager); 362 363 /// Return what kind of Pass Manager can manage this pass. 364 virtual PassManagerType getPotentialPassManagerType() const { 365 return PMT_BasicBlockPassManager; 366 } 367}; 368 369/// PMStack 370/// Top level pass manager (see PasManager.cpp) maintains active Pass Managers 371/// using PMStack. Each Pass implements assignPassManager() to connect itself 372/// with appropriate manager. assignPassManager() walks PMStack to find 373/// suitable manager. 374/// 375/// PMStack is just a wrapper around standard deque that overrides pop() and 376/// push() methods. 377class PMStack { 378public: 379 typedef std::deque<PMDataManager *>::reverse_iterator iterator; 380 iterator begin() { return S.rbegin(); } 381 iterator end() { return S.rend(); } 382 383 void handleLastUserOverflow(); 384 385 void pop(); 386 inline PMDataManager *top() { return S.back(); } 387 void push(Pass *P); 388 inline bool empty() { return S.empty(); } 389 390 void dump(); 391private: 392 std::deque<PMDataManager *> S; 393}; 394 395 396/// If the user specifies the -time-passes argument on an LLVM tool command line 397/// then the value of this boolean will be true, otherwise false. 398/// @brief This is the storage for the -time-passes option. 399extern bool TimePassesIsEnabled; 400 401} // End llvm namespace 402 403// Include support files that contain important APIs commonly used by Passes, 404// but that we want to separate out to make it easier to read the header files. 405// 406#include "llvm/PassSupport.h" 407#include "llvm/PassAnalysisSupport.h" 408 409#endif 410