Pass.h revision c2f12ab5e5258a949c0cfff074bf57fe0c08d4e5
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 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/DataTypes.h" 33#include "llvm/Support/Streams.h" 34#include <vector> 35#include <deque> 36#include <map> 37#include <iosfwd> 38#include <cassert> 39 40namespace llvm { 41 42class Value; 43class BasicBlock; 44class Function; 45class Module; 46class AnalysisUsage; 47class PassInfo; 48class ImmutablePass; 49class PMStack; 50class AnalysisResolver; 51class PMDataManager; 52 53// AnalysisID - Use the PassInfo to identify a pass... 54typedef const PassInfo* AnalysisID; 55 56/// Different types of internal pass managers. External pass managers 57/// (PassManager and FunctionPassManager) are not represented here. 58/// Ordering of pass manager types is important here. 59enum PassManagerType { 60 PMT_Unknown = 0, 61 PMT_ModulePassManager = 1, /// MPPassManager 62 PMT_CallGraphPassManager, /// CGPassManager 63 PMT_FunctionPassManager, /// FPPassManager 64 PMT_LoopPassManager, /// LPPassManager 65 PMT_BasicBlockPassManager, /// BBPassManager 66 PMT_Last 67}; 68 69//===----------------------------------------------------------------------===// 70/// Pass interface - Implemented by all 'passes'. Subclass this if you are an 71/// interprocedural optimization or you do not fit into any of the more 72/// constrained passes described below. 73/// 74class Pass { 75 AnalysisResolver *Resolver; // Used to resolve analysis 76 intptr_t PassID; 77 78 // AnalysisImpls - This keeps track of which passes implement the interfaces 79 // that are required by the current pass (to implement getAnalysis()). 80 // 81 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls; 82 83 void operator=(const Pass&); // DO NOT IMPLEMENT 84 Pass(const Pass &); // DO NOT IMPLEMENT 85public: 86 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {} 87 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)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 /// print - Print out the internal state of the pass. This is called by 104 /// Analyze to print out the contents of an analysis. Otherwise it is not 105 /// necessary to implement this method. Beware that the module pointer MAY be 106 /// null. This automatically forwards to a virtual function that does not 107 /// provide the Module* in case the analysis doesn't need it it can just be 108 /// ignored. 109 /// 110 virtual void print(std::ostream &O, const Module *M) const; 111 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 112 void dump() const; // dump - call print(std::cerr, 0); 113 114 /// Each pass is responsible for assigning a pass manager to itself. 115 /// PMS is the stack of available pass manager. 116 virtual void assignPassManager(PMStack &PMS, 117 PassManagerType T = PMT_Unknown) {} 118 /// Check if available pass managers are suitable for this pass or not. 119 virtual void preparePassManager(PMStack &PMS) {} 120 121 /// Return what kind of Pass Manager can manage this pass. 122 virtual PassManagerType getPotentialPassManagerType() const { 123 return PMT_Unknown; 124 } 125 126 // Access AnalysisResolver 127 inline void setResolver(AnalysisResolver *AR) { 128 assert (!Resolver && "Resolver is already set"); 129 Resolver = AR; 130 } 131 inline AnalysisResolver *getResolver() { 132 assert (Resolver && "Resolver is not set"); 133 return Resolver; 134 } 135 136 /// getAnalysisUsage - This function should be overriden by passes that need 137 /// analysis information to do their job. If a pass specifies that it uses a 138 /// particular analysis result to this function, it can then use the 139 /// getAnalysis<AnalysisType>() function, below. 140 /// 141 virtual void getAnalysisUsage(AnalysisUsage &Info) const { 142 // By default, no analysis results are used, all are invalidated. 143 } 144 145 /// releaseMemory() - This member can be implemented by a pass if it wants to 146 /// be able to release its memory when it is no longer needed. The default 147 /// behavior of passes is to hold onto memory for the entire duration of their 148 /// lifetime (which is the entire compile time). For pipelined passes, this 149 /// is not a big deal because that memory gets recycled every time the pass is 150 /// invoked on another program unit. For IP passes, it is more important to 151 /// free memory when it is unused. 152 /// 153 /// Optionally implement this function to release pass memory when it is no 154 /// longer used. 155 /// 156 virtual void releaseMemory() {} 157 158 /// verifyAnalysis() - This member can be implemented by a analysis pass to 159 /// check state of analysis information. 160 virtual void verifyAnalysis() const {} 161 162 // dumpPassStructure - Implement the -debug-passes=PassStructure option 163 virtual void dumpPassStructure(unsigned Offset = 0); 164 165 template<typename AnalysisClass> 166 static const PassInfo *getClassPassInfo() { 167 return lookupPassInfo(intptr_t(&AnalysisClass::ID)); 168 } 169 170 // lookupPassInfo - Return the pass info object for the specified pass class, 171 // or null if it is not known. 172 static const PassInfo *lookupPassInfo(intptr_t TI); 173 174 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses 175 /// to get to the analysis information that might be around that needs to be 176 /// updated. This is different than getAnalysis in that it can fail (ie the 177 /// analysis results haven't been computed), so should only be used if you 178 /// provide the capability to update an analysis that exists. This method is 179 /// often used by transformation APIs to update analysis results for a pass 180 /// automatically as the transform is performed. 181 /// 182 template<typename AnalysisType> 183 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h 184 185 /// mustPreserveAnalysisID - This method serves the same function as 186 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This 187 /// obviously cannot give you a properly typed instance of the class if you 188 /// don't have the class name available (use getAnalysisToUpdate if you do), 189 /// but it can tell you if you need to preserve the pass at least. 190 /// 191 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 192 193 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 194 /// to the analysis information that they claim to use by overriding the 195 /// getAnalysisUsage function. 196 /// 197 template<typename AnalysisType> 198 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 199 200 template<typename AnalysisType> 201 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h 202 203 template<typename AnalysisType> 204 AnalysisType &getAnalysisID(const PassInfo *PI) const; 205 206 template<typename AnalysisType> 207 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 208}; 209 210inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 211 P.print(OS, 0); return OS; 212} 213 214//===----------------------------------------------------------------------===// 215/// ModulePass class - This class is used to implement unstructured 216/// interprocedural optimizations and analyses. ModulePasses may do anything 217/// they want to the program. 218/// 219class ModulePass : public Pass { 220public: 221 /// runOnModule - Virtual method overriden by subclasses to process the module 222 /// being operated on. 223 virtual bool runOnModule(Module &M) = 0; 224 225 virtual void assignPassManager(PMStack &PMS, 226 PassManagerType T = PMT_ModulePassManager); 227 228 /// Return what kind of Pass Manager can manage this pass. 229 virtual PassManagerType getPotentialPassManagerType() const { 230 return PMT_ModulePassManager; 231 } 232 233 explicit ModulePass(intptr_t pid) : Pass(pid) {} 234 explicit ModulePass(const void *pid) : Pass(pid) {} 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 bool runOnModule(Module &M) { return false; } 258 259 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 260 explicit ImmutablePass(const void *pid) : ModulePass(pid) {} 261 262 // Force out-of-line virtual method. 263 virtual ~ImmutablePass(); 264}; 265 266//===----------------------------------------------------------------------===// 267/// FunctionPass class - This class is used to implement most global 268/// optimizations. Optimizations should subclass this class if they meet the 269/// following constraints: 270/// 271/// 1. Optimizations are organized globally, i.e., a function at a time 272/// 2. Optimizing a function does not cause the addition or removal of any 273/// functions in the module 274/// 275class FunctionPass : public Pass { 276public: 277 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 278 explicit FunctionPass(const void *pid) : Pass(pid) {} 279 280 /// doInitialization - Virtual method overridden by subclasses to do 281 /// any necessary per-module initialization. 282 /// 283 virtual bool doInitialization(Module &M) { return false; } 284 285 /// runOnFunction - Virtual method overriden by subclasses to do the 286 /// per-function processing of the pass. 287 /// 288 virtual bool runOnFunction(Function &F) = 0; 289 290 /// doFinalization - Virtual method overriden by subclasses to do any post 291 /// processing needed after all passes have run. 292 /// 293 virtual bool doFinalization(Module &M) { return false; } 294 295 /// runOnModule - On a module, we run this pass by initializing, 296 /// ronOnFunction'ing once for every function in the module, then by 297 /// finalizing. 298 /// 299 virtual bool runOnModule(Module &M); 300 301 /// run - On a function, we simply initialize, run the function, then 302 /// finalize. 303 /// 304 bool run(Function &F); 305 306 virtual void assignPassManager(PMStack &PMS, 307 PassManagerType T = PMT_FunctionPassManager); 308 309 /// Return what kind of Pass Manager can manage this pass. 310 virtual PassManagerType getPotentialPassManagerType() const { 311 return PMT_FunctionPassManager; 312 } 313}; 314 315 316 317//===----------------------------------------------------------------------===// 318/// BasicBlockPass class - This class is used to implement most local 319/// optimizations. Optimizations should subclass this class if they 320/// meet the following constraints: 321/// 1. Optimizations are local, operating on either a basic block or 322/// instruction at a time. 323/// 2. Optimizations do not modify the CFG of the contained function, or any 324/// other basic block in the function. 325/// 3. Optimizations conform to all of the constraints of FunctionPasses. 326/// 327class BasicBlockPass : public Pass { 328public: 329 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 330 explicit BasicBlockPass(const void *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 virtual void assignPassManager(PMStack &PMS, 364 PassManagerType T = PMT_BasicBlockPassManager); 365 366 /// Return what kind of Pass Manager can manage this pass. 367 virtual PassManagerType getPotentialPassManagerType() const { 368 return PMT_BasicBlockPassManager; 369 } 370}; 371 372/// PMStack 373/// Top level pass manager (see PassManager.cpp) maintains active Pass Managers 374/// using PMStack. Each Pass implements assignPassManager() to connect itself 375/// with appropriate manager. assignPassManager() walks PMStack to find 376/// suitable manager. 377/// 378/// PMStack is just a wrapper around standard deque that overrides pop() and 379/// push() methods. 380class PMStack { 381public: 382 typedef std::deque<PMDataManager *>::reverse_iterator iterator; 383 iterator begin() { return S.rbegin(); } 384 iterator end() { return S.rend(); } 385 386 void handleLastUserOverflow(); 387 388 void pop(); 389 inline PMDataManager *top() { return S.back(); } 390 void push(PMDataManager *PM); 391 inline bool empty() { return S.empty(); } 392 393 void dump(); 394private: 395 std::deque<PMDataManager *> S; 396}; 397 398 399/// If the user specifies the -time-passes argument on an LLVM tool command line 400/// then the value of this boolean will be true, otherwise false. 401/// @brief This is the storage for the -time-passes option. 402extern bool TimePassesIsEnabled; 403 404} // End llvm namespace 405 406// Include support files that contain important APIs commonly used by Passes, 407// but that we want to separate out to make it easier to read the header files. 408// 409#include "llvm/PassSupport.h" 410#include "llvm/PassAnalysisSupport.h" 411 412#endif 413