Pass.h revision e37879c23bfd97c9537b4e2398710256c289984c
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}; 69 70typedef enum PassManagerType PassManagerType; 71 72//===----------------------------------------------------------------------===// 73/// Pass interface - Implemented by all 'passes'. Subclass this if you are an 74/// interprocedural optimization or you do not fit into any of the more 75/// constrained passes described below. 76/// 77class Pass { 78 AnalysisResolver *Resolver; // Used to resolve analysis 79 const PassInfo *PassInfoCache; 80 81 // AnalysisImpls - This keeps track of which passes implement the interfaces 82 // that are required by the current pass (to implement getAnalysis()). 83 // 84 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls; 85 86 void operator=(const Pass&); // DO NOT IMPLEMENT 87 Pass(const Pass &); // DO NOT IMPLEMENT 88public: 89 Pass() : Resolver(0), PassInfoCache(0) {} 90 virtual ~Pass() {} // Destructor is virtual so we can be subclassed 91 92 /// getPassName - Return a nice clean name for a pass. This usually 93 /// implemented in terms of the name that is registered by one of the 94 /// Registration templates, but can be overloaded directly, and if nothing 95 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT 96 /// intelligible name for the pass. 97 /// 98 virtual const char *getPassName() const; 99 100 /// getPassInfo - Return the PassInfo data structure that corresponds to this 101 /// pass... If the pass has not been registered, this will return null. 102 /// 103 const PassInfo *getPassInfo() const; 104 105 /// runPass - Run this pass, returning true if a modification was made to the 106 /// module argument. This should be implemented by all concrete subclasses. 107 /// 108 virtual bool runPass(Module &M) { return false; } 109 virtual bool runPass(BasicBlock&) { return false; } 110 111 /// print - Print out the internal state of the pass. This is called by 112 /// Analyze to print out the contents of an analysis. Otherwise it is not 113 /// necessary to implement this method. Beware that the module pointer MAY be 114 /// null. This automatically forwards to a virtual function that does not 115 /// provide the Module* in case the analysis doesn't need it it can just be 116 /// ignored. 117 /// 118 virtual void print(std::ostream &O, const Module *M) const; 119 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 120 void dump() const; // dump - call print(std::cerr, 0); 121 122 virtual void assignPassManager(PMStack &PMS, 123 PassManagerType T = PMT_Unknown) {} 124 // Access AnalysisResolver 125 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; } 126 inline AnalysisResolver *getResolver() { return Resolver; } 127 128 /// getAnalysisUsage - This function should be overriden by passes that need 129 /// analysis information to do their job. If a pass specifies that it uses a 130 /// particular analysis result to this function, it can then use the 131 /// getAnalysis<AnalysisType>() function, below. 132 /// 133 virtual void getAnalysisUsage(AnalysisUsage &Info) const { 134 // By default, no analysis results are used, all are invalidated. 135 } 136 137 /// releaseMemory() - This member can be implemented by a pass if it wants to 138 /// be able to release its memory when it is no longer needed. The default 139 /// behavior of passes is to hold onto memory for the entire duration of their 140 /// lifetime (which is the entire compile time). For pipelined passes, this 141 /// is not a big deal because that memory gets recycled every time the pass is 142 /// invoked on another program unit. For IP passes, it is more important to 143 /// free memory when it is unused. 144 /// 145 /// Optionally implement this function to release pass memory when it is no 146 /// longer used. 147 /// 148 virtual void releaseMemory() {} 149 150 // dumpPassStructure - Implement the -debug-passes=PassStructure option 151 virtual void dumpPassStructure(unsigned Offset = 0); 152 153 template<typename AnalysisClass> 154 static const PassInfo *getClassPassInfo() { 155 return lookupPassInfo(typeid(AnalysisClass)); 156 } 157 158 // lookupPassInfo - Return the pass info object for the specified pass class, 159 // or null if it is not known. 160 static const PassInfo *lookupPassInfo(const std::type_info &TI); 161 162 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses 163 /// to get to the analysis information that might be around that needs to be 164 /// updated. This is different than getAnalysis in that it can fail (ie the 165 /// analysis results haven't been computed), so should only be used if you 166 /// provide the capability to update an analysis that exists. This method is 167 /// often used by transformation APIs to update analysis results for a pass 168 /// automatically as the transform is performed. 169 /// 170 template<typename AnalysisType> 171 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h 172 173 /// mustPreserveAnalysisID - This method serves the same function as 174 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This 175 /// obviously cannot give you a properly typed instance of the class if you 176 /// don't have the class name available (use getAnalysisToUpdate if you do), 177 /// but it can tell you if you need to preserve the pass at least. 178 /// 179 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 180 181 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 182 /// to the analysis information that they claim to use by overriding the 183 /// getAnalysisUsage function. 184 /// 185 template<typename AnalysisType> 186 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 187 188 template<typename AnalysisType> 189 AnalysisType &getAnalysisID(const PassInfo *PI) const; 190 191}; 192 193inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 194 P.print(OS, 0); return OS; 195} 196 197//===----------------------------------------------------------------------===// 198/// ModulePass class - This class is used to implement unstructured 199/// interprocedural optimizations and analyses. ModulePasses may do anything 200/// they want to the program. 201/// 202class ModulePass : public Pass { 203public: 204 /// runOnModule - Virtual method overriden by subclasses to process the module 205 /// being operated on. 206 virtual bool runOnModule(Module &M) = 0; 207 208 virtual bool runPass(Module &M) { return runOnModule(M); } 209 virtual bool runPass(BasicBlock&) { return false; } 210 211 virtual void assignPassManager(PMStack &PMS, 212 PassManagerType T = PMT_ModulePassManager); 213 // Force out-of-line virtual method. 214 virtual ~ModulePass(); 215}; 216 217 218//===----------------------------------------------------------------------===// 219/// ImmutablePass class - This class is used to provide information that does 220/// not need to be run. This is useful for things like target information and 221/// "basic" versions of AnalysisGroups. 222/// 223class ImmutablePass : public ModulePass { 224public: 225 /// initializePass - This method may be overriden by immutable passes to allow 226 /// them to perform various initialization actions they require. This is 227 /// primarily because an ImmutablePass can "require" another ImmutablePass, 228 /// and if it does, the overloaded version of initializePass may get access to 229 /// these passes with getAnalysis<>. 230 /// 231 virtual void initializePass() {} 232 233 /// ImmutablePasses are never run. 234 /// 235 virtual bool runOnModule(Module &M) { return false; } 236 237 // Force out-of-line virtual method. 238 virtual ~ImmutablePass(); 239}; 240 241//===----------------------------------------------------------------------===// 242/// FunctionPass class - This class is used to implement most global 243/// optimizations. Optimizations should subclass this class if they meet the 244/// following constraints: 245/// 246/// 1. Optimizations are organized globally, i.e., a function at a time 247/// 2. Optimizing a function does not cause the addition or removal of any 248/// functions in the module 249/// 250class FunctionPass : public ModulePass { 251public: 252 /// doInitialization - Virtual method overridden by subclasses to do 253 /// any necessary per-module initialization. 254 /// 255 virtual bool doInitialization(Module &M) { return false; } 256 257 /// runOnFunction - Virtual method overriden by subclasses to do the 258 /// per-function processing of the pass. 259 /// 260 virtual bool runOnFunction(Function &F) = 0; 261 262 /// doFinalization - Virtual method overriden by subclasses to do any post 263 /// processing needed after all passes have run. 264 /// 265 virtual bool doFinalization(Module &M) { return false; } 266 267 /// runOnModule - On a module, we run this pass by initializing, 268 /// ronOnFunction'ing once for every function in the module, then by 269 /// finalizing. 270 /// 271 virtual bool runOnModule(Module &M); 272 273 /// run - On a function, we simply initialize, run the function, then 274 /// finalize. 275 /// 276 bool run(Function &F); 277 278 virtual void assignPassManager(PMStack &PMS, 279 PassManagerType T = PMT_FunctionPassManager); 280}; 281 282 283 284//===----------------------------------------------------------------------===// 285/// BasicBlockPass class - This class is used to implement most local 286/// optimizations. Optimizations should subclass this class if they 287/// meet the following constraints: 288/// 1. Optimizations are local, operating on either a basic block or 289/// instruction at a time. 290/// 2. Optimizations do not modify the CFG of the contained function, or any 291/// other basic block in the function. 292/// 3. Optimizations conform to all of the constraints of FunctionPasses. 293/// 294class BasicBlockPass : public FunctionPass { 295public: 296 /// doInitialization - Virtual method overridden by subclasses to do 297 /// any necessary per-module initialization. 298 /// 299 virtual bool doInitialization(Module &M) { return false; } 300 301 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 302 /// to do any necessary per-function initialization. 303 /// 304 virtual bool doInitialization(Function &F) { return false; } 305 306 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 307 /// per-basicblock processing of the pass. 308 /// 309 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 310 311 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 312 /// do any post processing needed after all passes have run. 313 /// 314 virtual bool doFinalization(Function &F) { return false; } 315 316 /// doFinalization - Virtual method overriden by subclasses to do any post 317 /// processing needed after all passes have run. 318 /// 319 virtual bool doFinalization(Module &M) { return false; } 320 321 322 // To run this pass on a function, we simply call runOnBasicBlock once for 323 // each function. 324 // 325 bool runOnFunction(Function &F); 326 327 /// To run directly on the basic block, we initialize, runOnBasicBlock, then 328 /// finalize. 329 /// 330 virtual bool runPass(Module &M) { return false; } 331 virtual bool runPass(BasicBlock &BB); 332 333 virtual void assignPassManager(PMStack &PMS, 334 PassManagerType T = PMT_BasicBlockPassManager); 335}; 336 337/// PMStack 338/// Top level pass manager (see PasManager.cpp) maintains active Pass Managers 339/// using PMStack. Each Pass implements assignPassManager() to connect itself 340/// with appropriate manager. assignPassManager() walks PMStack to find 341/// suitable manager. 342/// 343/// PMStack is just a wrapper around standard deque that overrides pop() and 344/// push() methods. 345class PMStack { 346public: 347 typedef std::deque<PMDataManager *>::reverse_iterator iterator; 348 iterator begin() { return S.rbegin(); } 349 iterator end() { return S.rend(); } 350 351 void handleLastUserOverflow(); 352 353 void pop(); 354 inline PMDataManager *top() { return S.back(); } 355 void push(Pass *P); 356 inline bool empty() { return S.empty(); } 357 358 void dump(); 359private: 360 std::deque<PMDataManager *> S; 361}; 362 363 364/// If the user specifies the -time-passes argument on an LLVM tool command line 365/// then the value of this boolean will be true, otherwise false. 366/// @brief This is the storage for the -time-passes option. 367extern bool TimePassesIsEnabled; 368 369} // End llvm namespace 370 371// Include support files that contain important APIs commonly used by Passes, 372// but that we want to separate out to make it easier to read the header files. 373// 374#include "llvm/PassSupport.h" 375#include "llvm/PassAnalysisSupport.h" 376 377#endif 378