Pass.h revision 276222a5ae189ed5c6a2afb248d4c8f0335585b4
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 /// verifyAnalysis() - This member can be implemented by a analysis pass to 165 /// check state of analysis information. 166 virtual void verifyAnalysis() const {} 167 168 // dumpPassStructure - Implement the -debug-passes=PassStructure option 169 virtual void dumpPassStructure(unsigned Offset = 0); 170 171 template<typename AnalysisClass> 172 static const PassInfo *getClassPassInfo() { 173 return lookupPassInfo(intptr_t(&AnalysisClass::ID)); 174 } 175 176 // lookupPassInfo - Return the pass info object for the specified pass class, 177 // or null if it is not known. 178 static const PassInfo *lookupPassInfo(intptr_t TI); 179 180 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses 181 /// to get to the analysis information that might be around that needs to be 182 /// updated. This is different than getAnalysis in that it can fail (ie the 183 /// analysis results haven't been computed), so should only be used if you 184 /// provide the capability to update an analysis that exists. This method is 185 /// often used by transformation APIs to update analysis results for a pass 186 /// automatically as the transform is performed. 187 /// 188 template<typename AnalysisType> 189 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h 190 191 /// mustPreserveAnalysisID - This method serves the same function as 192 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This 193 /// obviously cannot give you a properly typed instance of the class if you 194 /// don't have the class name available (use getAnalysisToUpdate if you do), 195 /// but it can tell you if you need to preserve the pass at least. 196 /// 197 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 198 199 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 200 /// to the analysis information that they claim to use by overriding the 201 /// getAnalysisUsage function. 202 /// 203 template<typename AnalysisType> 204 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 205 206 template<typename AnalysisType> 207 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h 208 209 template<typename AnalysisType> 210 AnalysisType &getAnalysisID(const PassInfo *PI) const; 211 212 template<typename AnalysisType> 213 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 214}; 215 216inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 217 P.print(OS, 0); return OS; 218} 219 220//===----------------------------------------------------------------------===// 221/// ModulePass class - This class is used to implement unstructured 222/// interprocedural optimizations and analyses. ModulePasses may do anything 223/// they want to the program. 224/// 225class ModulePass : public Pass { 226public: 227 /// runOnModule - Virtual method overriden by subclasses to process the module 228 /// being operated on. 229 virtual bool runOnModule(Module &M) = 0; 230 231 virtual bool runPass(Module &M) { return runOnModule(M); } 232 virtual bool runPass(BasicBlock&) { return false; } 233 234 virtual void assignPassManager(PMStack &PMS, 235 PassManagerType T = PMT_ModulePassManager); 236 237 /// Return what kind of Pass Manager can manage this pass. 238 virtual PassManagerType getPotentialPassManagerType() const { 239 return PMT_ModulePassManager; 240 } 241 242 explicit ModulePass(intptr_t pid) : Pass(pid) {} 243 // Force out-of-line virtual method. 244 virtual ~ModulePass(); 245}; 246 247 248//===----------------------------------------------------------------------===// 249/// ImmutablePass class - This class is used to provide information that does 250/// not need to be run. This is useful for things like target information and 251/// "basic" versions of AnalysisGroups. 252/// 253class ImmutablePass : public ModulePass { 254public: 255 /// initializePass - This method may be overriden by immutable passes to allow 256 /// them to perform various initialization actions they require. This is 257 /// primarily because an ImmutablePass can "require" another ImmutablePass, 258 /// and if it does, the overloaded version of initializePass may get access to 259 /// these passes with getAnalysis<>. 260 /// 261 virtual void initializePass() {} 262 263 /// ImmutablePasses are never run. 264 /// 265 bool runOnModule(Module &M) { return false; } 266 267 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 268 // Force out-of-line virtual method. 269 virtual ~ImmutablePass(); 270}; 271 272//===----------------------------------------------------------------------===// 273/// FunctionPass class - This class is used to implement most global 274/// optimizations. Optimizations should subclass this class if they meet the 275/// following constraints: 276/// 277/// 1. Optimizations are organized globally, i.e., a function at a time 278/// 2. Optimizing a function does not cause the addition or removal of any 279/// functions in the module 280/// 281class FunctionPass : public Pass { 282public: 283 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 284 285 /// doInitialization - Virtual method overridden by subclasses to do 286 /// any necessary per-module initialization. 287 /// 288 virtual bool doInitialization(Module &M) { return false; } 289 290 /// runOnFunction - Virtual method overriden by subclasses to do the 291 /// per-function processing of the pass. 292 /// 293 virtual bool runOnFunction(Function &F) = 0; 294 295 /// doFinalization - Virtual method overriden by subclasses to do any post 296 /// processing needed after all passes have run. 297 /// 298 virtual bool doFinalization(Module &M) { return false; } 299 300 /// runOnModule - On a module, we run this pass by initializing, 301 /// ronOnFunction'ing once for every function in the module, then by 302 /// finalizing. 303 /// 304 virtual bool runOnModule(Module &M); 305 306 /// run - On a function, we simply initialize, run the function, then 307 /// finalize. 308 /// 309 bool run(Function &F); 310 311 virtual void assignPassManager(PMStack &PMS, 312 PassManagerType T = PMT_FunctionPassManager); 313 314 /// Return what kind of Pass Manager can manage this pass. 315 virtual PassManagerType getPotentialPassManagerType() const { 316 return PMT_FunctionPassManager; 317 } 318}; 319 320 321 322//===----------------------------------------------------------------------===// 323/// BasicBlockPass class - This class is used to implement most local 324/// optimizations. Optimizations should subclass this class if they 325/// meet the following constraints: 326/// 1. Optimizations are local, operating on either a basic block or 327/// instruction at a time. 328/// 2. Optimizations do not modify the CFG of the contained function, or any 329/// other basic block in the function. 330/// 3. Optimizations conform to all of the constraints of FunctionPasses. 331/// 332class BasicBlockPass : public Pass { 333public: 334 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 335 336 /// doInitialization - Virtual method overridden by subclasses to do 337 /// any necessary per-module initialization. 338 /// 339 virtual bool doInitialization(Module &M) { return false; } 340 341 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 342 /// to do any necessary per-function initialization. 343 /// 344 virtual bool doInitialization(Function &F) { return false; } 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 &F) { return false; } 355 356 /// doFinalization - Virtual method overriden by subclasses to do any post 357 /// processing needed after all passes have run. 358 /// 359 virtual bool doFinalization(Module &M) { return false; } 360 361 362 // To run this pass on a function, we simply call runOnBasicBlock once for 363 // each function. 364 // 365 bool runOnFunction(Function &F); 366 367 /// To run directly on the basic block, we initialize, runOnBasicBlock, then 368 /// finalize. 369 /// 370 virtual bool runPass(Module &M) { return false; } 371 virtual bool runPass(BasicBlock &BB); 372 373 virtual void assignPassManager(PMStack &PMS, 374 PassManagerType T = PMT_BasicBlockPassManager); 375 376 /// Return what kind of Pass Manager can manage this pass. 377 virtual PassManagerType getPotentialPassManagerType() const { 378 return PMT_BasicBlockPassManager; 379 } 380}; 381 382/// PMStack 383/// Top level pass manager (see PasManager.cpp) maintains active Pass Managers 384/// using PMStack. Each Pass implements assignPassManager() to connect itself 385/// with appropriate manager. assignPassManager() walks PMStack to find 386/// suitable manager. 387/// 388/// PMStack is just a wrapper around standard deque that overrides pop() and 389/// push() methods. 390class PMStack { 391public: 392 typedef std::deque<PMDataManager *>::reverse_iterator iterator; 393 iterator begin() { return S.rbegin(); } 394 iterator end() { return S.rend(); } 395 396 void handleLastUserOverflow(); 397 398 void pop(); 399 inline PMDataManager *top() { return S.back(); } 400 void push(Pass *P); 401 inline bool empty() { return S.empty(); } 402 403 void dump(); 404private: 405 std::deque<PMDataManager *> S; 406}; 407 408 409/// If the user specifies the -time-passes argument on an LLVM tool command line 410/// then the value of this boolean will be true, otherwise false. 411/// @brief This is the storage for the -time-passes option. 412extern bool TimePassesIsEnabled; 413 414} // End llvm namespace 415 416// Include support files that contain important APIs commonly used by Passes, 417// but that we want to separate out to make it easier to read the header files. 418// 419#include "llvm/PassSupport.h" 420#include "llvm/PassAnalysisSupport.h" 421 422#endif 423