Pass.h revision 22a1cf9d3a5c829d260bcf44ffe6b34ecf16076c
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 /// Each pass is responsible for assigning a pass manager to itself. 123 /// PMS is the stack of available pass manager. 124 virtual void assignPassManager(PMStack &PMS, 125 PassManagerType T = PMT_Unknown) {} 126 /// Check if available pass managers are suitable for this pass or not. 127 virtual void preparePassManager(PMStack &PMS) {} 128 129 // Access AnalysisResolver 130 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; } 131 inline AnalysisResolver *getResolver() { return Resolver; } 132 133 /// getAnalysisUsage - This function should be overriden by passes that need 134 /// analysis information to do their job. If a pass specifies that it uses a 135 /// particular analysis result to this function, it can then use the 136 /// getAnalysis<AnalysisType>() function, below. 137 /// 138 virtual void getAnalysisUsage(AnalysisUsage &Info) const { 139 // By default, no analysis results are used, all are invalidated. 140 } 141 142 /// releaseMemory() - This member can be implemented by a pass if it wants to 143 /// be able to release its memory when it is no longer needed. The default 144 /// behavior of passes is to hold onto memory for the entire duration of their 145 /// lifetime (which is the entire compile time). For pipelined passes, this 146 /// is not a big deal because that memory gets recycled every time the pass is 147 /// invoked on another program unit. For IP passes, it is more important to 148 /// free memory when it is unused. 149 /// 150 /// Optionally implement this function to release pass memory when it is no 151 /// longer used. 152 /// 153 virtual void releaseMemory() {} 154 155 // dumpPassStructure - Implement the -debug-passes=PassStructure option 156 virtual void dumpPassStructure(unsigned Offset = 0); 157 158 template<typename AnalysisClass> 159 static const PassInfo *getClassPassInfo() { 160 return lookupPassInfo(typeid(AnalysisClass)); 161 } 162 163 // lookupPassInfo - Return the pass info object for the specified pass class, 164 // or null if it is not known. 165 static const PassInfo *lookupPassInfo(const std::type_info &TI); 166 167 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses 168 /// to get to the analysis information that might be around that needs to be 169 /// updated. This is different than getAnalysis in that it can fail (ie the 170 /// analysis results haven't been computed), so should only be used if you 171 /// provide the capability to update an analysis that exists. This method is 172 /// often used by transformation APIs to update analysis results for a pass 173 /// automatically as the transform is performed. 174 /// 175 template<typename AnalysisType> 176 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h 177 178 /// mustPreserveAnalysisID - This method serves the same function as 179 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This 180 /// obviously cannot give you a properly typed instance of the class if you 181 /// don't have the class name available (use getAnalysisToUpdate if you do), 182 /// but it can tell you if you need to preserve the pass at least. 183 /// 184 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 185 186 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 187 /// to the analysis information that they claim to use by overriding the 188 /// getAnalysisUsage function. 189 /// 190 template<typename AnalysisType> 191 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 192 193 template<typename AnalysisType> 194 AnalysisType &getAnalysisID(const PassInfo *PI) const; 195 196}; 197 198inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 199 P.print(OS, 0); return OS; 200} 201 202//===----------------------------------------------------------------------===// 203/// ModulePass class - This class is used to implement unstructured 204/// interprocedural optimizations and analyses. ModulePasses may do anything 205/// they want to the program. 206/// 207class ModulePass : public Pass { 208public: 209 /// runOnModule - Virtual method overriden by subclasses to process the module 210 /// being operated on. 211 virtual bool runOnModule(Module &M) = 0; 212 213 virtual bool runPass(Module &M) { return runOnModule(M); } 214 virtual bool runPass(BasicBlock&) { return false; } 215 216 virtual void assignPassManager(PMStack &PMS, 217 PassManagerType T = PMT_ModulePassManager); 218 // Force out-of-line virtual method. 219 virtual ~ModulePass(); 220}; 221 222 223//===----------------------------------------------------------------------===// 224/// ImmutablePass class - This class is used to provide information that does 225/// not need to be run. This is useful for things like target information and 226/// "basic" versions of AnalysisGroups. 227/// 228class ImmutablePass : public ModulePass { 229public: 230 /// initializePass - This method may be overriden by immutable passes to allow 231 /// them to perform various initialization actions they require. This is 232 /// primarily because an ImmutablePass can "require" another ImmutablePass, 233 /// and if it does, the overloaded version of initializePass may get access to 234 /// these passes with getAnalysis<>. 235 /// 236 virtual void initializePass() {} 237 238 /// ImmutablePasses are never run. 239 /// 240 virtual bool runOnModule(Module &M) { return false; } 241 242 // Force out-of-line virtual method. 243 virtual ~ImmutablePass(); 244}; 245 246//===----------------------------------------------------------------------===// 247/// FunctionPass class - This class is used to implement most global 248/// optimizations. Optimizations should subclass this class if they meet the 249/// following constraints: 250/// 251/// 1. Optimizations are organized globally, i.e., a function at a time 252/// 2. Optimizing a function does not cause the addition or removal of any 253/// functions in the module 254/// 255class FunctionPass : public Pass { 256public: 257 /// doInitialization - Virtual method overridden by subclasses to do 258 /// any necessary per-module initialization. 259 /// 260 virtual bool doInitialization(Module &M) { return false; } 261 262 /// runOnFunction - Virtual method overriden by subclasses to do the 263 /// per-function processing of the pass. 264 /// 265 virtual bool runOnFunction(Function &F) = 0; 266 267 /// doFinalization - Virtual method overriden by subclasses to do any post 268 /// processing needed after all passes have run. 269 /// 270 virtual bool doFinalization(Module &M) { return false; } 271 272 /// runOnModule - On a module, we run this pass by initializing, 273 /// ronOnFunction'ing once for every function in the module, then by 274 /// finalizing. 275 /// 276 virtual bool runOnModule(Module &M); 277 278 /// run - On a function, we simply initialize, run the function, then 279 /// finalize. 280 /// 281 bool run(Function &F); 282 283 virtual void assignPassManager(PMStack &PMS, 284 PassManagerType T = PMT_FunctionPassManager); 285}; 286 287 288 289//===----------------------------------------------------------------------===// 290/// BasicBlockPass class - This class is used to implement most local 291/// optimizations. Optimizations should subclass this class if they 292/// meet the following constraints: 293/// 1. Optimizations are local, operating on either a basic block or 294/// instruction at a time. 295/// 2. Optimizations do not modify the CFG of the contained function, or any 296/// other basic block in the function. 297/// 3. Optimizations conform to all of the constraints of FunctionPasses. 298/// 299class BasicBlockPass : public Pass { 300public: 301 /// doInitialization - Virtual method overridden by subclasses to do 302 /// any necessary per-module initialization. 303 /// 304 virtual bool doInitialization(Module &M) { return false; } 305 306 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 307 /// to do any necessary per-function initialization. 308 /// 309 virtual bool doInitialization(Function &F) { return false; } 310 311 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 312 /// per-basicblock processing of the pass. 313 /// 314 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 315 316 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 317 /// do any post processing needed after all passes have run. 318 /// 319 virtual bool doFinalization(Function &F) { return false; } 320 321 /// doFinalization - Virtual method overriden by subclasses to do any post 322 /// processing needed after all passes have run. 323 /// 324 virtual bool doFinalization(Module &M) { return false; } 325 326 327 // To run this pass on a function, we simply call runOnBasicBlock once for 328 // each function. 329 // 330 bool runOnFunction(Function &F); 331 332 /// To run directly on the basic block, we initialize, runOnBasicBlock, then 333 /// finalize. 334 /// 335 virtual bool runPass(Module &M) { return false; } 336 virtual bool runPass(BasicBlock &BB); 337 338 virtual void assignPassManager(PMStack &PMS, 339 PassManagerType T = PMT_BasicBlockPassManager); 340}; 341 342/// PMStack 343/// Top level pass manager (see PasManager.cpp) maintains active Pass Managers 344/// using PMStack. Each Pass implements assignPassManager() to connect itself 345/// with appropriate manager. assignPassManager() walks PMStack to find 346/// suitable manager. 347/// 348/// PMStack is just a wrapper around standard deque that overrides pop() and 349/// push() methods. 350class PMStack { 351public: 352 typedef std::deque<PMDataManager *>::reverse_iterator iterator; 353 iterator begin() { return S.rbegin(); } 354 iterator end() { return S.rend(); } 355 356 void handleLastUserOverflow(); 357 358 void pop(); 359 inline PMDataManager *top() { return S.back(); } 360 void push(Pass *P); 361 inline bool empty() { return S.empty(); } 362 363 void dump(); 364private: 365 std::deque<PMDataManager *> S; 366}; 367 368 369/// If the user specifies the -time-passes argument on an LLVM tool command line 370/// then the value of this boolean will be true, otherwise false. 371/// @brief This is the storage for the -time-passes option. 372extern bool TimePassesIsEnabled; 373 374} // End llvm namespace 375 376// Include support files that contain important APIs commonly used by Passes, 377// but that we want to separate out to make it easier to read the header files. 378// 379#include "llvm/PassSupport.h" 380#include "llvm/PassAnalysisSupport.h" 381 382#endif 383