Pass.h revision e922c0201916e0b980ab3cfe91e1413e68d55647
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/Module.h" 33#include "llvm/Support/DataTypes.h" 34#include "llvm/Support/Streams.h" 35#include <cassert> 36#include <iosfwd> 37#include <utility> 38#include <vector> 39 40namespace llvm { 41 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 68//===----------------------------------------------------------------------===// 69/// Pass interface - Implemented by all 'passes'. Subclass this if you are an 70/// interprocedural optimization or you do not fit into any of the more 71/// constrained passes described below. 72/// 73class Pass { 74 AnalysisResolver *Resolver; // Used to resolve analysis 75 intptr_t PassID; 76 77 void operator=(const Pass&); // DO NOT IMPLEMENT 78 Pass(const Pass &); // DO NOT IMPLEMENT 79 80public: 81 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) { 82 assert(pid && "pid cannot be 0"); 83 } 84 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) { 85 assert(pid && "pid cannot be 0"); 86 } 87 virtual ~Pass(); 88 89 /// getPassName - Return a nice clean name for a pass. This usually 90 /// implemented in terms of the name that is registered by one of the 91 /// Registration templates, but can be overloaded directly. 92 /// 93 virtual const char *getPassName() const; 94 95 /// getPassInfo - Return the PassInfo data structure that corresponds to this 96 /// pass... If the pass has not been registered, this will return null. 97 /// 98 const PassInfo *getPassInfo() const; 99 100 /// print - Print out the internal state of the pass. This is called by 101 /// Analyze to print out the contents of an analysis. Otherwise it is not 102 /// necessary to implement this method. Beware that the module pointer MAY be 103 /// null. This automatically forwards to a virtual function that does not 104 /// provide the Module* in case the analysis doesn't need it it can just be 105 /// ignored. 106 /// 107 virtual void print(std::ostream &O, const Module *M) const; 108 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 109 void dump() const; // dump - call print(std::cerr, 0); 110 111 /// Each pass is responsible for assigning a pass manager to itself. 112 /// PMS is the stack of available pass manager. 113 virtual void assignPassManager(PMStack &, 114 PassManagerType = PMT_Unknown) {} 115 /// Check if available pass managers are suitable for this pass or not. 116 virtual void preparePassManager(PMStack &) {} 117 118 /// Return what kind of Pass Manager can manage this pass. 119 virtual PassManagerType getPotentialPassManagerType() const { 120 return PMT_Unknown; 121 } 122 123 // Access AnalysisResolver 124 inline void setResolver(AnalysisResolver *AR) { 125 assert (!Resolver && "Resolver is already set"); 126 Resolver = AR; 127 } 128 inline AnalysisResolver *getResolver() { 129 return Resolver; 130 } 131 132 /// getAnalysisUsage - This function should be overriden by passes that need 133 /// analysis information to do their job. If a pass specifies that it uses a 134 /// particular analysis result to this function, it can then use the 135 /// getAnalysis<AnalysisType>() function, below. 136 /// 137 virtual void getAnalysisUsage(AnalysisUsage &) const { 138 // By default, no analysis results are used, all are invalidated. 139 } 140 141 /// releaseMemory() - This member can be implemented by a pass if it wants to 142 /// be able to release its memory when it is no longer needed. The default 143 /// behavior of passes is to hold onto memory for the entire duration of their 144 /// lifetime (which is the entire compile time). For pipelined passes, this 145 /// is not a big deal because that memory gets recycled every time the pass is 146 /// invoked on another program unit. For IP passes, it is more important to 147 /// free memory when it is unused. 148 /// 149 /// Optionally implement this function to release pass memory when it is no 150 /// longer used. 151 /// 152 virtual void releaseMemory() {} 153 154 /// verifyAnalysis() - This member can be implemented by a analysis pass to 155 /// check state of analysis information. 156 virtual void verifyAnalysis() const {} 157 158 // dumpPassStructure - Implement the -debug-passes=PassStructure option 159 virtual void dumpPassStructure(unsigned Offset = 0); 160 161 template<typename AnalysisClass> 162 static const PassInfo *getClassPassInfo() { 163 return lookupPassInfo(intptr_t(&AnalysisClass::ID)); 164 } 165 166 // lookupPassInfo - Return the pass info object for the specified pass class, 167 // or null if it is not known. 168 static const PassInfo *lookupPassInfo(intptr_t TI); 169 170 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to 171 /// get analysis information that might be around, for example to update it. 172 /// This is different than getAnalysis in that it can fail (if the analysis 173 /// results haven't been computed), so should only be used if you can handle 174 /// the case when the analysis is not available. This method is often used by 175 /// transformation APIs to update analysis results for a pass automatically as 176 /// the transform is performed. 177 /// 178 template<typename AnalysisType> AnalysisType * 179 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h 180 181 /// mustPreserveAnalysisID - This method serves the same function as 182 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This 183 /// obviously cannot give you a properly typed instance of the class if you 184 /// don't have the class name available (use getAnalysisIfAvailable if you 185 /// do), but it can tell you if you need to preserve the pass at least. 186 /// 187 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 188 189 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 190 /// to the analysis information that they claim to use by overriding the 191 /// getAnalysisUsage function. 192 /// 193 template<typename AnalysisType> 194 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 195 196 template<typename AnalysisType> 197 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h 198 199 template<typename AnalysisType> 200 AnalysisType &getAnalysisID(const PassInfo *PI) const; 201 202 template<typename AnalysisType> 203 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 204}; 205 206inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 207 P.print(OS, 0); return OS; 208} 209 210//===----------------------------------------------------------------------===// 211/// ModulePass class - This class is used to implement unstructured 212/// interprocedural optimizations and analyses. ModulePasses may do anything 213/// they want to the program. 214/// 215class ModulePass : public Pass { 216public: 217 /// runOnModule - Virtual method overriden by subclasses to process the module 218 /// being operated on. 219 virtual bool runOnModule(Module &M) = 0; 220 221 virtual void assignPassManager(PMStack &PMS, 222 PassManagerType T = PMT_ModulePassManager); 223 224 /// Return what kind of Pass Manager can manage this pass. 225 virtual PassManagerType getPotentialPassManagerType() const { 226 return PMT_ModulePassManager; 227 } 228 229 explicit ModulePass(intptr_t pid) : Pass(pid) {} 230 explicit ModulePass(const void *pid) : Pass(pid) {} 231 // Force out-of-line virtual method. 232 virtual ~ModulePass(); 233}; 234 235 236//===----------------------------------------------------------------------===// 237/// ImmutablePass class - This class is used to provide information that does 238/// not need to be run. This is useful for things like target information and 239/// "basic" versions of AnalysisGroups. 240/// 241class ImmutablePass : public ModulePass { 242public: 243 /// initializePass - This method may be overriden by immutable passes to allow 244 /// them to perform various initialization actions they require. This is 245 /// primarily because an ImmutablePass can "require" another ImmutablePass, 246 /// and if it does, the overloaded version of initializePass may get access to 247 /// these passes with getAnalysis<>. 248 /// 249 virtual void initializePass() {} 250 251 /// ImmutablePasses are never run. 252 /// 253 bool runOnModule(Module &) { return false; } 254 255 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 256 explicit ImmutablePass(const void *pid) 257 : ModulePass(pid) {} 258 259 // Force out-of-line virtual method. 260 virtual ~ImmutablePass(); 261}; 262 263//===----------------------------------------------------------------------===// 264/// FunctionPass class - This class is used to implement most global 265/// optimizations. Optimizations should subclass this class if they meet the 266/// following constraints: 267/// 268/// 1. Optimizations are organized globally, i.e., a function at a time 269/// 2. Optimizing a function does not cause the addition or removal of any 270/// functions in the module 271/// 272class FunctionPass : public Pass { 273public: 274 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 275 explicit FunctionPass(const void *pid) : Pass(pid) {} 276 277 /// doInitialization - Virtual method overridden by subclasses to do 278 /// any necessary per-module initialization. 279 /// 280 virtual bool doInitialization(Module &M) { return false; } 281 282 /// runOnFunction - Virtual method overriden by subclasses to do the 283 /// per-function processing of the pass. 284 /// 285 virtual bool runOnFunction(Function &F) = 0; 286 287 /// doFinalization - Virtual method overriden by subclasses to do any post 288 /// processing needed after all passes have run. 289 /// 290 virtual bool doFinalization(Module &) { return false; } 291 292 /// runOnModule - On a module, we run this pass by initializing, 293 /// ronOnFunction'ing once for every function in the module, then by 294 /// finalizing. 295 /// 296 virtual bool runOnModule(Module &M); 297 298 /// run - On a function, we simply initialize, run the function, then 299 /// finalize. 300 /// 301 bool run(Function &F); 302 303 virtual void assignPassManager(PMStack &PMS, 304 PassManagerType T = PMT_FunctionPassManager); 305 306 /// Return what kind of Pass Manager can manage this pass. 307 virtual PassManagerType getPotentialPassManagerType() const { 308 return PMT_FunctionPassManager; 309 } 310}; 311 312 313 314//===----------------------------------------------------------------------===// 315/// BasicBlockPass class - This class is used to implement most local 316/// optimizations. Optimizations should subclass this class if they 317/// meet the following constraints: 318/// 1. Optimizations are local, operating on either a basic block or 319/// instruction at a time. 320/// 2. Optimizations do not modify the CFG of the contained function, or any 321/// other basic block in the function. 322/// 3. Optimizations conform to all of the constraints of FunctionPasses. 323/// 324class BasicBlockPass : public Pass { 325public: 326 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 327 explicit BasicBlockPass(const void *pid) : Pass(pid) {} 328 329 /// doInitialization - Virtual method overridden by subclasses to do 330 /// any necessary per-module initialization. 331 /// 332 virtual bool doInitialization(Module &M) { return false; } 333 334 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 335 /// to do any necessary per-function initialization. 336 /// 337 virtual bool doInitialization(Function &) { return false; } 338 339 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 340 /// per-basicblock processing of the pass. 341 /// 342 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 343 344 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 345 /// do any post processing needed after all passes have run. 346 /// 347 virtual bool doFinalization(Function &) { return false; } 348 349 /// doFinalization - Virtual method overriden by subclasses to do any post 350 /// processing needed after all passes have run. 351 /// 352 virtual bool doFinalization(Module &) { return false; } 353 354 355 // To run this pass on a function, we simply call runOnBasicBlock once for 356 // each function. 357 // 358 bool runOnFunction(Function &F); 359 360 virtual void assignPassManager(PMStack &PMS, 361 PassManagerType T = PMT_BasicBlockPassManager); 362 363 /// Return what kind of Pass Manager can manage this pass. 364 virtual PassManagerType getPotentialPassManagerType() const { 365 return PMT_BasicBlockPassManager; 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