Pass.h revision b42295df4da77a34519d0c49840a8b997d3f0b7c
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 <cassert> 38 39namespace llvm { 40 41class Value; 42class BasicBlock; 43class Function; 44class Module; 45class AnalysisUsage; 46class PassInfo; 47class ImmutablePass; 48class PMStack; 49class AnalysisResolver; 50class PMDataManager; 51 52// AnalysisID - Use the PassInfo to identify a pass... 53typedef const PassInfo* AnalysisID; 54 55/// Different types of internal pass managers. External pass managers 56/// (PassManager and FunctionPassManager) are not represented here. 57/// Ordering of pass manager types is important here. 58enum PassManagerType { 59 PMT_Unknown = 0, 60 PMT_ModulePassManager = 1, /// MPPassManager 61 PMT_CallGraphPassManager, /// CGPassManager 62 PMT_FunctionPassManager, /// FPPassManager 63 PMT_LoopPassManager, /// LPPassManager 64 PMT_BasicBlockPassManager, /// BBPassManager 65 PMT_Last 66}; 67 68typedef enum PassManagerType PassManagerType; 69 70//===----------------------------------------------------------------------===// 71/// Pass interface - Implemented by all 'passes'. Subclass this if you are an 72/// interprocedural optimization or you do not fit into any of the more 73/// constrained passes described below. 74/// 75class Pass { 76 AnalysisResolver *Resolver; // Used to resolve analysis 77 intptr_t PassID; 78 79 // AnalysisImpls - This keeps track of which passes implement the interfaces 80 // that are required by the current pass (to implement getAnalysis()). 81 // 82 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls; 83 84 void operator=(const Pass&); // DO NOT IMPLEMENT 85 Pass(const Pass &); // DO NOT IMPLEMENT 86public: 87 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {} 88 virtual ~Pass(); 89 90 /// getPassName - Return a nice clean name for a pass. This usually 91 /// implemented in terms of the name that is registered by one of the 92 /// Registration templates, but can be overloaded directly, and if nothing 93 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT 94 /// intelligible name for the pass. 95 /// 96 virtual const char *getPassName() const; 97 98 /// getPassInfo - Return the PassInfo data structure that corresponds to this 99 /// pass... If the pass has not been registered, this will return null. 100 /// 101 const PassInfo *getPassInfo() const; 102 103 /// runPass - Run this pass, returning true if a modification was made to the 104 /// module argument. This should be implemented by all concrete subclasses. 105 /// 106 virtual bool runPass(Module &M) { return false; } 107 virtual bool runPass(BasicBlock&) { return false; } 108 109 /// print - Print out the internal state of the pass. This is called by 110 /// Analyze to print out the contents of an analysis. Otherwise it is not 111 /// necessary to implement this method. Beware that the module pointer MAY be 112 /// null. This automatically forwards to a virtual function that does not 113 /// provide the Module* in case the analysis doesn't need it it can just be 114 /// ignored. 115 /// 116 virtual void print(std::ostream &O, const Module *M) const; 117 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 118 void dump() const; // dump - call print(std::cerr, 0); 119 120 /// Each pass is responsible for assigning a pass manager to itself. 121 /// PMS is the stack of available pass manager. 122 virtual void assignPassManager(PMStack &PMS, 123 PassManagerType T = PMT_Unknown) {} 124 /// Check if available pass managers are suitable for this pass or not. 125 virtual void preparePassManager(PMStack &PMS) {} 126 127 /// Return what kind of Pass Manager can manage this pass. 128 virtual PassManagerType getPotentialPassManagerType() const { 129 return PMT_Unknown; 130 } 131 132 // Access AnalysisResolver 133 inline void setResolver(AnalysisResolver *AR) { 134 assert (!Resolver && "Resolver is already set"); 135 Resolver = AR; 136 } 137 inline AnalysisResolver *getResolver() { 138 assert (Resolver && "Resolver is not set"); 139 return Resolver; 140 } 141 142 /// getAnalysisUsage - This function should be overriden by passes that need 143 /// analysis information to do their job. If a pass specifies that it uses a 144 /// particular analysis result to this function, it can then use the 145 /// getAnalysis<AnalysisType>() function, below. 146 /// 147 virtual void getAnalysisUsage(AnalysisUsage &Info) const { 148 // By default, no analysis results are used, all are invalidated. 149 } 150 151 /// releaseMemory() - This member can be implemented by a pass if it wants to 152 /// be able to release its memory when it is no longer needed. The default 153 /// behavior of passes is to hold onto memory for the entire duration of their 154 /// lifetime (which is the entire compile time). For pipelined passes, this 155 /// is not a big deal because that memory gets recycled every time the pass is 156 /// invoked on another program unit. For IP passes, it is more important to 157 /// free memory when it is unused. 158 /// 159 /// Optionally implement this function to release pass memory when it is no 160 /// longer used. 161 /// 162 virtual void releaseMemory() {} 163 164 // dumpPassStructure - Implement the -debug-passes=PassStructure option 165 virtual void dumpPassStructure(unsigned Offset = 0); 166 167 template<typename AnalysisClass> 168 static const PassInfo *getClassPassInfo() { 169 return lookupPassInfo((intptr_t)&AnalysisClass::ID); 170 } 171 172 // lookupPassInfo - Return the pass info object for the specified pass class, 173 // or null if it is not known. 174 static const PassInfo *lookupPassInfo(intptr_t TI); 175 176 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses 177 /// to get to the analysis information that might be around that needs to be 178 /// updated. This is different than getAnalysis in that it can fail (ie the 179 /// analysis results haven't been computed), so should only be used if you 180 /// provide the capability to update an analysis that exists. This method is 181 /// often used by transformation APIs to update analysis results for a pass 182 /// automatically as the transform is performed. 183 /// 184 template<typename AnalysisType> 185 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h 186 187 /// mustPreserveAnalysisID - This method serves the same function as 188 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This 189 /// obviously cannot give you a properly typed instance of the class if you 190 /// don't have the class name available (use getAnalysisToUpdate if you do), 191 /// but it can tell you if you need to preserve the pass at least. 192 /// 193 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 194 195 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 196 /// to the analysis information that they claim to use by overriding the 197 /// getAnalysisUsage function. 198 /// 199 template<typename AnalysisType> 200 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 201 202 template<typename AnalysisType> 203 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h 204 205 template<typename AnalysisType> 206 AnalysisType &getAnalysisID(const PassInfo *PI) const; 207 208 template<typename AnalysisType> 209 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 210}; 211 212inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 213 P.print(OS, 0); return OS; 214} 215 216//===----------------------------------------------------------------------===// 217/// ModulePass class - This class is used to implement unstructured 218/// interprocedural optimizations and analyses. ModulePasses may do anything 219/// they want to the program. 220/// 221class ModulePass : public Pass { 222public: 223 /// runOnModule - Virtual method overriden by subclasses to process the module 224 /// being operated on. 225 virtual bool runOnModule(Module &M) = 0; 226 227 virtual bool runPass(Module &M) { return runOnModule(M); } 228 virtual bool runPass(BasicBlock&) { return false; } 229 230 virtual void assignPassManager(PMStack &PMS, 231 PassManagerType T = PMT_ModulePassManager); 232 233 /// Return what kind of Pass Manager can manage this pass. 234 virtual PassManagerType getPotentialPassManagerType() const { 235 return PMT_ModulePassManager; 236 } 237 238 explicit ModulePass(intptr_t pid) : Pass(pid) {} 239 // Force out-of-line virtual method. 240 virtual ~ModulePass(); 241}; 242 243 244//===----------------------------------------------------------------------===// 245/// ImmutablePass class - This class is used to provide information that does 246/// not need to be run. This is useful for things like target information and 247/// "basic" versions of AnalysisGroups. 248/// 249class ImmutablePass : public ModulePass { 250public: 251 /// initializePass - This method may be overriden by immutable passes to allow 252 /// them to perform various initialization actions they require. This is 253 /// primarily because an ImmutablePass can "require" another ImmutablePass, 254 /// and if it does, the overloaded version of initializePass may get access to 255 /// these passes with getAnalysis<>. 256 /// 257 virtual void initializePass() {} 258 259 /// ImmutablePasses are never run. 260 /// 261 virtual bool runOnModule(Module &M) { return false; } 262 263 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 264 // Force out-of-line virtual method. 265 virtual ~ImmutablePass(); 266}; 267 268//===----------------------------------------------------------------------===// 269/// FunctionPass class - This class is used to implement most global 270/// optimizations. Optimizations should subclass this class if they meet the 271/// following constraints: 272/// 273/// 1. Optimizations are organized globally, i.e., a function at a time 274/// 2. Optimizing a function does not cause the addition or removal of any 275/// functions in the module 276/// 277class FunctionPass : public Pass { 278public: 279 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 280 281 /// doInitialization - Virtual method overridden by subclasses to do 282 /// any necessary per-module initialization. 283 /// 284 virtual bool doInitialization(Module &M) { return false; } 285 286 /// runOnFunction - Virtual method overriden by subclasses to do the 287 /// per-function processing of the pass. 288 /// 289 virtual bool runOnFunction(Function &F) = 0; 290 291 /// doFinalization - Virtual method overriden by subclasses to do any post 292 /// processing needed after all passes have run. 293 /// 294 virtual bool doFinalization(Module &M) { return false; } 295 296 /// runOnModule - On a module, we run this pass by initializing, 297 /// ronOnFunction'ing once for every function in the module, then by 298 /// finalizing. 299 /// 300 virtual bool runOnModule(Module &M); 301 302 /// run - On a function, we simply initialize, run the function, then 303 /// finalize. 304 /// 305 bool run(Function &F); 306 307 virtual void assignPassManager(PMStack &PMS, 308 PassManagerType T = PMT_FunctionPassManager); 309 310 /// Return what kind of Pass Manager can manage this pass. 311 virtual PassManagerType getPotentialPassManagerType() const { 312 return PMT_FunctionPassManager; 313 } 314}; 315 316 317 318//===----------------------------------------------------------------------===// 319/// BasicBlockPass class - This class is used to implement most local 320/// optimizations. Optimizations should subclass this class if they 321/// meet the following constraints: 322/// 1. Optimizations are local, operating on either a basic block or 323/// instruction at a time. 324/// 2. Optimizations do not modify the CFG of the contained function, or any 325/// other basic block in the function. 326/// 3. Optimizations conform to all of the constraints of FunctionPasses. 327/// 328class BasicBlockPass : public Pass { 329public: 330 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 331 332 /// doInitialization - Virtual method overridden by subclasses to do 333 /// any necessary per-module initialization. 334 /// 335 virtual bool doInitialization(Module &M) { return false; } 336 337 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 338 /// to do any necessary per-function initialization. 339 /// 340 virtual bool doInitialization(Function &F) { return false; } 341 342 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 343 /// per-basicblock processing of the pass. 344 /// 345 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 346 347 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 348 /// do any post processing needed after all passes have run. 349 /// 350 virtual bool doFinalization(Function &F) { return false; } 351 352 /// doFinalization - Virtual method overriden by subclasses to do any post 353 /// processing needed after all passes have run. 354 /// 355 virtual bool doFinalization(Module &M) { return false; } 356 357 358 // To run this pass on a function, we simply call runOnBasicBlock once for 359 // each function. 360 // 361 bool runOnFunction(Function &F); 362 363 /// To run directly on the basic block, we initialize, runOnBasicBlock, then 364 /// finalize. 365 /// 366 virtual bool runPass(Module &M) { return false; } 367 virtual bool runPass(BasicBlock &BB); 368 369 virtual void assignPassManager(PMStack &PMS, 370 PassManagerType T = PMT_BasicBlockPassManager); 371 372 /// Return what kind of Pass Manager can manage this pass. 373 virtual PassManagerType getPotentialPassManagerType() const { 374 return PMT_BasicBlockPassManager; 375 } 376}; 377 378/// PMStack 379/// Top level pass manager (see PasManager.cpp) maintains active Pass Managers 380/// using PMStack. Each Pass implements assignPassManager() to connect itself 381/// with appropriate manager. assignPassManager() walks PMStack to find 382/// suitable manager. 383/// 384/// PMStack is just a wrapper around standard deque that overrides pop() and 385/// push() methods. 386class PMStack { 387public: 388 typedef std::deque<PMDataManager *>::reverse_iterator iterator; 389 iterator begin() { return S.rbegin(); } 390 iterator end() { return S.rend(); } 391 392 void handleLastUserOverflow(); 393 394 void pop(); 395 inline PMDataManager *top() { return S.back(); } 396 void push(Pass *P); 397 inline bool empty() { return S.empty(); } 398 399 void dump(); 400private: 401 std::deque<PMDataManager *> S; 402}; 403 404 405/// If the user specifies the -time-passes argument on an LLVM tool command line 406/// then the value of this boolean will be true, otherwise false. 407/// @brief This is the storage for the -time-passes option. 408extern bool TimePassesIsEnabled; 409 410} // End llvm namespace 411 412// Include support files that contain important APIs commonly used by Passes, 413// but that we want to separate out to make it easier to read the header files. 414// 415#include "llvm/PassSupport.h" 416#include "llvm/PassAnalysisSupport.h" 417 418#endif 419