Pass.h revision 200581
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/System/DataTypes.h" 33#include <cassert> 34#include <utility> 35#include <vector> 36 37namespace llvm { 38 39class BasicBlock; 40class Function; 41class Module; 42class AnalysisUsage; 43class PassInfo; 44class ImmutablePass; 45class PMStack; 46class AnalysisResolver; 47class PMDataManager; 48class raw_ostream; 49class StringRef; 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 76 void operator=(const Pass&); // DO NOT IMPLEMENT 77 Pass(const Pass &); // DO NOT IMPLEMENT 78 79public: 80 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) { 81 assert(pid && "pid cannot be 0"); 82 } 83 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) { 84 assert(pid && "pid cannot be 0"); 85 } 86 virtual ~Pass(); 87 88 /// getPassName - Return a nice clean name for a pass. This usually 89 /// implemented in terms of the name that is registered by one of the 90 /// Registration templates, but can be overloaded directly. 91 /// 92 virtual const char *getPassName() const; 93 94 /// getPassInfo - Return the PassInfo data structure that corresponds to this 95 /// pass... If the pass has not been registered, this will return null. 96 /// 97 const PassInfo *getPassInfo() const; 98 99 /// print - Print out the internal state of the pass. This is called by 100 /// Analyze to print out the contents of an analysis. Otherwise it is not 101 /// necessary to implement this method. Beware that the module pointer MAY be 102 /// null. This automatically forwards to a virtual function that does not 103 /// provide the Module* in case the analysis doesn't need it it can just be 104 /// ignored. 105 /// 106 virtual void print(raw_ostream &O, const Module *M) const; 107 void dump() const; // dump - Print to stderr. 108 109 /// Each pass is responsible for assigning a pass manager to itself. 110 /// PMS is the stack of available pass manager. 111 virtual void assignPassManager(PMStack &, 112 PassManagerType = PMT_Unknown) {} 113 /// Check if available pass managers are suitable for this pass or not. 114 virtual void preparePassManager(PMStack &); 115 116 /// Return what kind of Pass Manager can manage this pass. 117 virtual PassManagerType getPotentialPassManagerType() const; 118 119 // Access AnalysisResolver 120 inline void setResolver(AnalysisResolver *AR) { 121 assert (!Resolver && "Resolver is already set"); 122 Resolver = AR; 123 } 124 inline AnalysisResolver *getResolver() { 125 return Resolver; 126 } 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 &) const; 134 135 /// releaseMemory() - This member can be implemented by a pass if it wants to 136 /// be able to release its memory when it is no longer needed. The default 137 /// behavior of passes is to hold onto memory for the entire duration of their 138 /// lifetime (which is the entire compile time). For pipelined passes, this 139 /// is not a big deal because that memory gets recycled every time the pass is 140 /// invoked on another program unit. For IP passes, it is more important to 141 /// free memory when it is unused. 142 /// 143 /// Optionally implement this function to release pass memory when it is no 144 /// longer used. 145 /// 146 virtual void releaseMemory(); 147 148 /// verifyAnalysis() - This member can be implemented by a analysis pass to 149 /// check state of analysis information. 150 virtual void verifyAnalysis() const; 151 152 // dumpPassStructure - Implement the -debug-passes=PassStructure option 153 virtual void dumpPassStructure(unsigned Offset = 0); 154 155 template<typename AnalysisClass> 156 static const PassInfo *getClassPassInfo() { 157 return lookupPassInfo(intptr_t(&AnalysisClass::ID)); 158 } 159 160 // lookupPassInfo - Return the pass info object for the specified pass class, 161 // or null if it is not known. 162 static const PassInfo *lookupPassInfo(intptr_t TI); 163 164 // lookupPassInfo - Return the pass info object for the pass with the given 165 // argument string, or null if it is not known. 166 static const PassInfo *lookupPassInfo(StringRef Arg); 167 168 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to 169 /// get analysis information that might be around, for example to update it. 170 /// This is different than getAnalysis in that it can fail (if the analysis 171 /// results haven't been computed), so should only be used if you can handle 172 /// the case when the analysis is not available. This method is often used by 173 /// transformation APIs to update analysis results for a pass automatically as 174 /// the transform is performed. 175 /// 176 template<typename AnalysisType> AnalysisType * 177 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h 178 179 /// mustPreserveAnalysisID - This method serves the same function as 180 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This 181 /// obviously cannot give you a properly typed instance of the class if you 182 /// don't have the class name available (use getAnalysisIfAvailable if you 183 /// do), but it can tell you if you need to preserve the pass at least. 184 /// 185 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 186 187 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 188 /// to the analysis information that they claim to use by overriding the 189 /// getAnalysisUsage function. 190 /// 191 template<typename AnalysisType> 192 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 193 194 template<typename AnalysisType> 195 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h 196 197 template<typename AnalysisType> 198 AnalysisType &getAnalysisID(const PassInfo *PI) const; 199 200 template<typename AnalysisType> 201 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 202}; 203 204 205//===----------------------------------------------------------------------===// 206/// ModulePass class - This class is used to implement unstructured 207/// interprocedural optimizations and analyses. ModulePasses may do anything 208/// they want to the program. 209/// 210class ModulePass : public Pass { 211public: 212 /// runOnModule - Virtual method overriden by subclasses to process the module 213 /// being operated on. 214 virtual bool runOnModule(Module &M) = 0; 215 216 virtual void assignPassManager(PMStack &PMS, 217 PassManagerType T = PMT_ModulePassManager); 218 219 /// Return what kind of Pass Manager can manage this pass. 220 virtual PassManagerType getPotentialPassManagerType() const; 221 222 explicit ModulePass(intptr_t pid) : Pass(pid) {} 223 explicit ModulePass(const void *pid) : Pass(pid) {} 224 // Force out-of-line virtual method. 225 virtual ~ModulePass(); 226}; 227 228 229//===----------------------------------------------------------------------===// 230/// ImmutablePass class - This class is used to provide information that does 231/// not need to be run. This is useful for things like target information and 232/// "basic" versions of AnalysisGroups. 233/// 234class ImmutablePass : public ModulePass { 235public: 236 /// initializePass - This method may be overriden by immutable passes to allow 237 /// them to perform various initialization actions they require. This is 238 /// primarily because an ImmutablePass can "require" another ImmutablePass, 239 /// and if it does, the overloaded version of initializePass may get access to 240 /// these passes with getAnalysis<>. 241 /// 242 virtual void initializePass(); 243 244 /// ImmutablePasses are never run. 245 /// 246 bool runOnModule(Module &) { return false; } 247 248 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 249 explicit ImmutablePass(const void *pid) 250 : ModulePass(pid) {} 251 252 // Force out-of-line virtual method. 253 virtual ~ImmutablePass(); 254}; 255 256//===----------------------------------------------------------------------===// 257/// FunctionPass class - This class is used to implement most global 258/// optimizations. Optimizations should subclass this class if they meet the 259/// following constraints: 260/// 261/// 1. Optimizations are organized globally, i.e., a function at a time 262/// 2. Optimizing a function does not cause the addition or removal of any 263/// functions in the module 264/// 265class FunctionPass : public Pass { 266public: 267 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 268 explicit FunctionPass(const void *pid) : Pass(pid) {} 269 270 /// doInitialization - Virtual method overridden by subclasses to do 271 /// any necessary per-module initialization. 272 /// 273 virtual bool doInitialization(Module &); 274 275 /// runOnFunction - Virtual method overriden by subclasses to do the 276 /// per-function processing of the pass. 277 /// 278 virtual bool runOnFunction(Function &F) = 0; 279 280 /// doFinalization - Virtual method overriden by subclasses to do any post 281 /// processing needed after all passes have run. 282 /// 283 virtual bool doFinalization(Module &); 284 285 /// runOnModule - On a module, we run this pass by initializing, 286 /// ronOnFunction'ing once for every function in the module, then by 287 /// finalizing. 288 /// 289 virtual bool runOnModule(Module &M); 290 291 /// run - On a function, we simply initialize, run the function, then 292 /// finalize. 293 /// 294 bool run(Function &F); 295 296 virtual void assignPassManager(PMStack &PMS, 297 PassManagerType T = PMT_FunctionPassManager); 298 299 /// Return what kind of Pass Manager can manage this pass. 300 virtual PassManagerType getPotentialPassManagerType() const; 301}; 302 303 304 305//===----------------------------------------------------------------------===// 306/// BasicBlockPass class - This class is used to implement most local 307/// optimizations. Optimizations should subclass this class if they 308/// meet the following constraints: 309/// 1. Optimizations are local, operating on either a basic block or 310/// instruction at a time. 311/// 2. Optimizations do not modify the CFG of the contained function, or any 312/// other basic block in the function. 313/// 3. Optimizations conform to all of the constraints of FunctionPasses. 314/// 315class BasicBlockPass : public Pass { 316public: 317 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 318 explicit BasicBlockPass(const void *pid) : Pass(pid) {} 319 320 /// doInitialization - Virtual method overridden by subclasses to do 321 /// any necessary per-module initialization. 322 /// 323 virtual bool doInitialization(Module &); 324 325 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 326 /// to do any necessary per-function initialization. 327 /// 328 virtual bool doInitialization(Function &); 329 330 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 331 /// per-basicblock processing of the pass. 332 /// 333 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 334 335 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 336 /// do any post processing needed after all passes have run. 337 /// 338 virtual bool doFinalization(Function &); 339 340 /// doFinalization - Virtual method overriden by subclasses to do any post 341 /// processing needed after all passes have run. 342 /// 343 virtual bool doFinalization(Module &); 344 345 346 // To run this pass on a function, we simply call runOnBasicBlock once for 347 // each function. 348 // 349 bool runOnFunction(Function &F); 350 351 virtual void assignPassManager(PMStack &PMS, 352 PassManagerType T = PMT_BasicBlockPassManager); 353 354 /// Return what kind of Pass Manager can manage this pass. 355 virtual PassManagerType getPotentialPassManagerType() const; 356}; 357 358/// If the user specifies the -time-passes argument on an LLVM tool command line 359/// then the value of this boolean will be true, otherwise false. 360/// @brief This is the storage for the -time-passes option. 361extern bool TimePassesIsEnabled; 362 363} // End llvm namespace 364 365// Include support files that contain important APIs commonly used by Passes, 366// but that we want to separate out to make it easier to read the header files. 367// 368#include "llvm/PassSupport.h" 369#include "llvm/PassAnalysisSupport.h" 370 371#endif 372