Pass.h revision 07cf79ef537caff6d39145f190a28a336e629b6f
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; 51class LLVMContext; 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 void operator=(const Pass&); // DO NOT IMPLEMENT 79 Pass(const Pass &); // DO NOT IMPLEMENT 80 81protected: 82 LLVMContext *Context; 83 84public: 85 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) { 86 assert(pid && "pid cannot be 0"); 87 } 88 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) { 89 assert(pid && "pid cannot be 0"); 90 } 91 virtual ~Pass(); 92 93 /// getPassName - Return a nice clean name for a pass. This usually 94 /// implemented in terms of the name that is registered by one of the 95 /// Registration templates, but can be overloaded directly. 96 /// 97 virtual const char *getPassName() const; 98 99 /// getPassInfo - Return the PassInfo data structure that corresponds to this 100 /// pass... If the pass has not been registered, this will return null. 101 /// 102 const PassInfo *getPassInfo() const; 103 104 /// print - Print out the internal state of the pass. This is called by 105 /// Analyze to print out the contents of an analysis. Otherwise it is not 106 /// necessary to implement this method. Beware that the module pointer MAY be 107 /// null. This automatically forwards to a virtual function that does not 108 /// provide the Module* in case the analysis doesn't need it it can just be 109 /// ignored. 110 /// 111 virtual void print(std::ostream &O, const Module *M) const; 112 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 113 void dump() const; // dump - call print(std::cerr, 0); 114 115 /// Each pass is responsible for assigning a pass manager to itself. 116 /// PMS is the stack of available pass manager. 117 virtual void assignPassManager(PMStack &, 118 PassManagerType = PMT_Unknown) {} 119 /// Check if available pass managers are suitable for this pass or not. 120 virtual void preparePassManager(PMStack &) {} 121 122 /// Return what kind of Pass Manager can manage this pass. 123 virtual PassManagerType getPotentialPassManagerType() const { 124 return PMT_Unknown; 125 } 126 127 // Access AnalysisResolver 128 inline void setResolver(AnalysisResolver *AR) { 129 assert (!Resolver && "Resolver is already set"); 130 Resolver = AR; 131 } 132 inline AnalysisResolver *getResolver() { 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 &) 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 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to 175 /// get analysis information that might be around, for example to update it. 176 /// This is different than getAnalysis in that it can fail (if the analysis 177 /// results haven't been computed), so should only be used if you can handle 178 /// the case when the analysis is not available. This method is often used by 179 /// transformation APIs to update analysis results for a pass automatically as 180 /// the transform is performed. 181 /// 182 template<typename AnalysisType> AnalysisType * 183 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h 184 185 /// mustPreserveAnalysisID - This method serves the same function as 186 /// getAnalysisIfAvailable, 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 getAnalysisIfAvailable if you 189 /// do), 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 &) { return false; } 258 259 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 260 explicit ImmutablePass(const void *pid) 261 : ModulePass(pid) {} 262 263 // Force out-of-line virtual method. 264 virtual ~ImmutablePass(); 265}; 266 267//===----------------------------------------------------------------------===// 268/// FunctionPass class - This class is used to implement most global 269/// optimizations. Optimizations should subclass this class if they meet the 270/// following constraints: 271/// 272/// 1. Optimizations are organized globally, i.e., a function at a time 273/// 2. Optimizing a function does not cause the addition or removal of any 274/// functions in the module 275/// 276class FunctionPass : public Pass { 277public: 278 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 279 explicit FunctionPass(const void *pid) : Pass(pid) {} 280 281 /// doInitialization - Virtual method overridden by subclasses to do 282 /// any necessary per-module initialization. 283 /// 284 virtual bool doInitialization(Module &M) { 285 Context = &M.getContext(); 286 return false; 287 } 288 289 /// runOnFunction - Virtual method overriden by subclasses to do the 290 /// per-function processing of the pass. 291 /// 292 virtual bool runOnFunction(Function &F) = 0; 293 294 /// doFinalization - Virtual method overriden by subclasses to do any post 295 /// processing needed after all passes have run. 296 /// 297 virtual bool doFinalization(Module &) { return false; } 298 299 /// runOnModule - On a module, we run this pass by initializing, 300 /// ronOnFunction'ing once for every function in the module, then by 301 /// finalizing. 302 /// 303 virtual bool runOnModule(Module &M); 304 305 /// run - On a function, we simply initialize, run the function, then 306 /// finalize. 307 /// 308 bool run(Function &F); 309 310 virtual void assignPassManager(PMStack &PMS, 311 PassManagerType T = PMT_FunctionPassManager); 312 313 /// Return what kind of Pass Manager can manage this pass. 314 virtual PassManagerType getPotentialPassManagerType() const { 315 return PMT_FunctionPassManager; 316 } 317}; 318 319 320 321//===----------------------------------------------------------------------===// 322/// BasicBlockPass class - This class is used to implement most local 323/// optimizations. Optimizations should subclass this class if they 324/// meet the following constraints: 325/// 1. Optimizations are local, operating on either a basic block or 326/// instruction at a time. 327/// 2. Optimizations do not modify the CFG of the contained function, or any 328/// other basic block in the function. 329/// 3. Optimizations conform to all of the constraints of FunctionPasses. 330/// 331class BasicBlockPass : public Pass { 332public: 333 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 334 explicit BasicBlockPass(const void *pid) : Pass(pid) {} 335 336 /// doInitialization - Virtual method overridden by subclasses to do 337 /// any necessary per-module initialization. 338 /// 339 virtual bool doInitialization(Module &M) { 340 Context = &M.getContext(); 341 return false; 342 } 343 344 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 345 /// to do any necessary per-function initialization. 346 /// 347 virtual bool doInitialization(Function &) { return false; } 348 349 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 350 /// per-basicblock processing of the pass. 351 /// 352 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 353 354 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 355 /// do any post processing needed after all passes have run. 356 /// 357 virtual bool doFinalization(Function &) { return false; } 358 359 /// doFinalization - Virtual method overriden by subclasses to do any post 360 /// processing needed after all passes have run. 361 /// 362 virtual bool doFinalization(Module &) { return false; } 363 364 365 // To run this pass on a function, we simply call runOnBasicBlock once for 366 // each function. 367 // 368 bool runOnFunction(Function &F); 369 370 virtual void assignPassManager(PMStack &PMS, 371 PassManagerType T = PMT_BasicBlockPassManager); 372 373 /// Return what kind of Pass Manager can manage this pass. 374 virtual PassManagerType getPotentialPassManagerType() const { 375 return PMT_BasicBlockPassManager; 376 } 377}; 378 379/// If the user specifies the -time-passes argument on an LLVM tool command line 380/// then the value of this boolean will be true, otherwise false. 381/// @brief This is the storage for the -time-passes option. 382extern bool TimePassesIsEnabled; 383 384} // End llvm namespace 385 386// Include support files that contain important APIs commonly used by Passes, 387// but that we want to separate out to make it easier to read the header files. 388// 389#include "llvm/PassSupport.h" 390#include "llvm/PassAnalysisSupport.h" 391 392#endif 393