Pass.h revision 1465d61bdd36cfd6021036a527895f0dd358e97d
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 <cassert> 35#include <iosfwd> 36#include <utility> 37#include <vector> 38 39namespace llvm { 40 41class BasicBlock; 42class Function; 43class Module; 44class AnalysisUsage; 45class PassInfo; 46class ImmutablePass; 47class PMStack; 48class AnalysisResolver; 49class PMDataManager; 50 51// AnalysisID - Use the PassInfo to identify a pass... 52typedef const PassInfo* AnalysisID; 53 54/// Different types of internal pass managers. External pass managers 55/// (PassManager and FunctionPassManager) are not represented here. 56/// Ordering of pass manager types is important here. 57enum PassManagerType { 58 PMT_Unknown = 0, 59 PMT_ModulePassManager = 1, /// MPPassManager 60 PMT_CallGraphPassManager, /// CGPassManager 61 PMT_FunctionPassManager, /// FPPassManager 62 PMT_LoopPassManager, /// LPPassManager 63 PMT_BasicBlockPassManager, /// BBPassManager 64 PMT_Last 65}; 66 67//===----------------------------------------------------------------------===// 68/// Pass interface - Implemented by all 'passes'. Subclass this if you are an 69/// interprocedural optimization or you do not fit into any of the more 70/// constrained passes described below. 71/// 72class Pass { 73 AnalysisResolver *Resolver; // Used to resolve analysis 74 intptr_t PassID; 75 // AnalysisImpls - This keeps track of which passes implement the interfaces 76 // that are required by the current pass (to implement getAnalysis()). 77 // 78 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls; 79 80 void operator=(const Pass&); // DO NOT IMPLEMENT 81 Pass(const Pass &); // DO NOT IMPLEMENT 82public: 83 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) { 84 assert(pid && "pid cannot be 0"); 85 } 86 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) { 87 assert(pid && "pid cannot be 0"); 88 } 89 virtual ~Pass(); 90 91 /// getPassName - Return a nice clean name for a pass. This usually 92 /// implemented in terms of the name that is registered by one of the 93 /// Registration templates, but can be overloaded directly. 94 /// 95 virtual const char *getPassName() const; 96 97 /// getPassInfo - Return the PassInfo data structure that corresponds to this 98 /// pass... If the pass has not been registered, this will return null. 99 /// 100 const PassInfo *getPassInfo() const; 101 102 /// print - Print out the internal state of the pass. This is called by 103 /// Analyze to print out the contents of an analysis. Otherwise it is not 104 /// necessary to implement this method. Beware that the module pointer MAY be 105 /// null. This automatically forwards to a virtual function that does not 106 /// provide the Module* in case the analysis doesn't need it it can just be 107 /// ignored. 108 /// 109 virtual void print(std::ostream &O, const Module *M) const; 110 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 111 void dump() const; // dump - call print(std::cerr, 0); 112 113 /// Each pass is responsible for assigning a pass manager to itself. 114 /// PMS is the stack of available pass manager. 115 virtual void assignPassManager(PMStack &, 116 PassManagerType = PMT_Unknown) {} 117 /// Check if available pass managers are suitable for this pass or not. 118 virtual void preparePassManager(PMStack &) {} 119 120 /// Return what kind of Pass Manager can manage this pass. 121 virtual PassManagerType getPotentialPassManagerType() const { 122 return PMT_Unknown; 123 } 124 125 // Access AnalysisResolver 126 inline void setResolver(AnalysisResolver *AR) { 127 assert (!Resolver && "Resolver is already set"); 128 Resolver = AR; 129 } 130 inline AnalysisResolver *getResolver() { 131 return Resolver; 132 } 133 134 /// getAnalysisUsage - This function should be overriden by passes that need 135 /// analysis information to do their job. If a pass specifies that it uses a 136 /// particular analysis result to this function, it can then use the 137 /// getAnalysis<AnalysisType>() function, below. 138 /// 139 virtual void getAnalysisUsage(AnalysisUsage &) const { 140 // By default, no analysis results are used, all are invalidated. 141 } 142 143 /// releaseMemory() - This member can be implemented by a pass if it wants to 144 /// be able to release its memory when it is no longer needed. The default 145 /// behavior of passes is to hold onto memory for the entire duration of their 146 /// lifetime (which is the entire compile time). For pipelined passes, this 147 /// is not a big deal because that memory gets recycled every time the pass is 148 /// invoked on another program unit. For IP passes, it is more important to 149 /// free memory when it is unused. 150 /// 151 /// Optionally implement this function to release pass memory when it is no 152 /// longer used. 153 /// 154 virtual void releaseMemory() {} 155 156 /// verifyAnalysis() - This member can be implemented by a analysis pass to 157 /// check state of analysis information. 158 virtual void verifyAnalysis() const {} 159 160 // dumpPassStructure - Implement the -debug-passes=PassStructure option 161 virtual void dumpPassStructure(unsigned Offset = 0); 162 163 template<typename AnalysisClass> 164 static const PassInfo *getClassPassInfo() { 165 return lookupPassInfo(intptr_t(&AnalysisClass::ID)); 166 } 167 168 // lookupPassInfo - Return the pass info object for the specified pass class, 169 // or null if it is not known. 170 static const PassInfo *lookupPassInfo(intptr_t TI); 171 172 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to 173 /// get analysis information that might be around, for example to update it. 174 /// This is different than getAnalysis in that it can fail (if the analysis 175 /// results haven't been computed), so should only be used if you can handle 176 /// the case when the analysis is not available. This method is often used by 177 /// transformation APIs to update analysis results for a pass automatically as 178 /// the transform is performed. 179 /// 180 template<typename AnalysisType> AnalysisType * 181 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h 182 183 /// mustPreserveAnalysisID - This method serves the same function as 184 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This 185 /// obviously cannot give you a properly typed instance of the class if you 186 /// don't have the class name available (use getAnalysisIfAvailable if you 187 /// do), but it can tell you if you need to preserve the pass at least. 188 /// 189 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 190 191 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 192 /// to the analysis information that they claim to use by overriding the 193 /// getAnalysisUsage function. 194 /// 195 template<typename AnalysisType> 196 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 197 198 template<typename AnalysisType> 199 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h 200 201 template<typename AnalysisType> 202 AnalysisType &getAnalysisID(const PassInfo *PI) const; 203 204 template<typename AnalysisType> 205 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 206}; 207 208inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 209 P.print(OS, 0); return OS; 210} 211 212//===----------------------------------------------------------------------===// 213/// ModulePass class - This class is used to implement unstructured 214/// interprocedural optimizations and analyses. ModulePasses may do anything 215/// they want to the program. 216/// 217class ModulePass : public Pass { 218public: 219 /// runOnModule - Virtual method overriden by subclasses to process the module 220 /// being operated on. 221 virtual bool runOnModule(Module &M) = 0; 222 223 virtual void assignPassManager(PMStack &PMS, 224 PassManagerType T = PMT_ModulePassManager); 225 226 /// Return what kind of Pass Manager can manage this pass. 227 virtual PassManagerType getPotentialPassManagerType() const { 228 return PMT_ModulePassManager; 229 } 230 231 explicit ModulePass(intptr_t pid) : Pass(pid) {} 232 explicit ModulePass(const void *pid) : Pass(pid) {} 233 // Force out-of-line virtual method. 234 virtual ~ModulePass(); 235}; 236 237 238//===----------------------------------------------------------------------===// 239/// ImmutablePass class - This class is used to provide information that does 240/// not need to be run. This is useful for things like target information and 241/// "basic" versions of AnalysisGroups. 242/// 243class ImmutablePass : public ModulePass { 244public: 245 /// initializePass - This method may be overriden by immutable passes to allow 246 /// them to perform various initialization actions they require. This is 247 /// primarily because an ImmutablePass can "require" another ImmutablePass, 248 /// and if it does, the overloaded version of initializePass may get access to 249 /// these passes with getAnalysis<>. 250 /// 251 virtual void initializePass() {} 252 253 /// ImmutablePasses are never run. 254 /// 255 bool runOnModule(Module &) { return false; } 256 257 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 258 explicit ImmutablePass(const void *pid) 259 : ModulePass(pid) {} 260 261 // Force out-of-line virtual method. 262 virtual ~ImmutablePass(); 263}; 264 265//===----------------------------------------------------------------------===// 266/// FunctionPass class - This class is used to implement most global 267/// optimizations. Optimizations should subclass this class if they meet the 268/// following constraints: 269/// 270/// 1. Optimizations are organized globally, i.e., a function at a time 271/// 2. Optimizing a function does not cause the addition or removal of any 272/// functions in the module 273/// 274class FunctionPass : public Pass { 275public: 276 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 277 explicit FunctionPass(const void *pid) : Pass(pid) {} 278 279 /// doInitialization - Virtual method overridden by subclasses to do 280 /// any necessary per-module initialization. 281 /// 282 virtual bool doInitialization(Module &) { return false; } 283 284 /// runOnFunction - Virtual method overriden by subclasses to do the 285 /// per-function processing of the pass. 286 /// 287 virtual bool runOnFunction(Function &F) = 0; 288 289 /// doFinalization - Virtual method overriden by subclasses to do any post 290 /// processing needed after all passes have run. 291 /// 292 virtual bool doFinalization(Module &) { return false; } 293 294 /// runOnModule - On a module, we run this pass by initializing, 295 /// ronOnFunction'ing once for every function in the module, then by 296 /// finalizing. 297 /// 298 virtual bool runOnModule(Module &M); 299 300 /// run - On a function, we simply initialize, run the function, then 301 /// finalize. 302 /// 303 bool run(Function &F); 304 305 virtual void assignPassManager(PMStack &PMS, 306 PassManagerType T = PMT_FunctionPassManager); 307 308 /// Return what kind of Pass Manager can manage this pass. 309 virtual PassManagerType getPotentialPassManagerType() const { 310 return PMT_FunctionPassManager; 311 } 312}; 313 314 315 316//===----------------------------------------------------------------------===// 317/// BasicBlockPass class - This class is used to implement most local 318/// optimizations. Optimizations should subclass this class if they 319/// meet the following constraints: 320/// 1. Optimizations are local, operating on either a basic block or 321/// instruction at a time. 322/// 2. Optimizations do not modify the CFG of the contained function, or any 323/// other basic block in the function. 324/// 3. Optimizations conform to all of the constraints of FunctionPasses. 325/// 326class BasicBlockPass : public Pass { 327public: 328 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 329 explicit BasicBlockPass(const void *pid) : Pass(pid) {} 330 331 /// doInitialization - Virtual method overridden by subclasses to do 332 /// any necessary per-module initialization. 333 /// 334 virtual bool doInitialization(Module &) { return false; } 335 336 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 337 /// to do any necessary per-function initialization. 338 /// 339 virtual bool doInitialization(Function &) { return false; } 340 341 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 342 /// per-basicblock processing of the pass. 343 /// 344 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 345 346 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 347 /// do any post processing needed after all passes have run. 348 /// 349 virtual bool doFinalization(Function &) { return false; } 350 351 /// doFinalization - Virtual method overriden by subclasses to do any post 352 /// processing needed after all passes have run. 353 /// 354 virtual bool doFinalization(Module &) { return false; } 355 356 357 // To run this pass on a function, we simply call runOnBasicBlock once for 358 // each function. 359 // 360 bool runOnFunction(Function &F); 361 362 virtual void assignPassManager(PMStack &PMS, 363 PassManagerType T = PMT_BasicBlockPassManager); 364 365 /// Return what kind of Pass Manager can manage this pass. 366 virtual PassManagerType getPotentialPassManagerType() const { 367 return PMT_BasicBlockPassManager; 368 } 369}; 370 371/// If the user specifies the -time-passes argument on an LLVM tool command line 372/// then the value of this boolean will be true, otherwise false. 373/// @brief This is the storage for the -time-passes option. 374extern bool TimePassesIsEnabled; 375 376} // End llvm namespace 377 378// Include support files that contain important APIs commonly used by Passes, 379// but that we want to separate out to make it easier to read the header files. 380// 381#include "llvm/PassSupport.h" 382#include "llvm/PassAnalysisSupport.h" 383 384#endif 385