Pass.h revision 199481
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 return PMT_Unknown; 119 } 120 121 // Access AnalysisResolver 122 inline void setResolver(AnalysisResolver *AR) { 123 assert (!Resolver && "Resolver is already set"); 124 Resolver = AR; 125 } 126 inline AnalysisResolver *getResolver() { 127 return Resolver; 128 } 129 130 /// getAnalysisUsage - This function should be overriden by passes that need 131 /// analysis information to do their job. If a pass specifies that it uses a 132 /// particular analysis result to this function, it can then use the 133 /// getAnalysis<AnalysisType>() function, below. 134 /// 135 virtual void getAnalysisUsage(AnalysisUsage &) const { 136 // By default, no analysis results are used, all are invalidated. 137 } 138 139 /// releaseMemory() - This member can be implemented by a pass if it wants to 140 /// be able to release its memory when it is no longer needed. The default 141 /// behavior of passes is to hold onto memory for the entire duration of their 142 /// lifetime (which is the entire compile time). For pipelined passes, this 143 /// is not a big deal because that memory gets recycled every time the pass is 144 /// invoked on another program unit. For IP passes, it is more important to 145 /// free memory when it is unused. 146 /// 147 /// Optionally implement this function to release pass memory when it is no 148 /// longer used. 149 /// 150 virtual void releaseMemory() {} 151 152 /// verifyAnalysis() - This member can be implemented by a analysis pass to 153 /// check state of analysis information. 154 virtual void verifyAnalysis() const {} 155 156 // dumpPassStructure - Implement the -debug-passes=PassStructure option 157 virtual void dumpPassStructure(unsigned Offset = 0); 158 159 template<typename AnalysisClass> 160 static const PassInfo *getClassPassInfo() { 161 return lookupPassInfo(intptr_t(&AnalysisClass::ID)); 162 } 163 164 // lookupPassInfo - Return the pass info object for the specified pass class, 165 // or null if it is not known. 166 static const PassInfo *lookupPassInfo(intptr_t TI); 167 168 // lookupPassInfo - Return the pass info object for the pass with the given 169 // argument string, or null if it is not known. 170 static const PassInfo *lookupPassInfo(StringRef Arg); 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}; 207 208 209//===----------------------------------------------------------------------===// 210/// ModulePass class - This class is used to implement unstructured 211/// interprocedural optimizations and analyses. ModulePasses may do anything 212/// they want to the program. 213/// 214class ModulePass : public Pass { 215public: 216 /// runOnModule - Virtual method overriden by subclasses to process the module 217 /// being operated on. 218 virtual bool runOnModule(Module &M) = 0; 219 220 virtual void assignPassManager(PMStack &PMS, 221 PassManagerType T = PMT_ModulePassManager); 222 223 /// Return what kind of Pass Manager can manage this pass. 224 virtual PassManagerType getPotentialPassManagerType() const { 225 return PMT_ModulePassManager; 226 } 227 228 explicit ModulePass(intptr_t pid) : Pass(pid) {} 229 explicit ModulePass(const void *pid) : Pass(pid) {} 230 // Force out-of-line virtual method. 231 virtual ~ModulePass(); 232}; 233 234 235//===----------------------------------------------------------------------===// 236/// ImmutablePass class - This class is used to provide information that does 237/// not need to be run. This is useful for things like target information and 238/// "basic" versions of AnalysisGroups. 239/// 240class ImmutablePass : public ModulePass { 241public: 242 /// initializePass - This method may be overriden by immutable passes to allow 243 /// them to perform various initialization actions they require. This is 244 /// primarily because an ImmutablePass can "require" another ImmutablePass, 245 /// and if it does, the overloaded version of initializePass may get access to 246 /// these passes with getAnalysis<>. 247 /// 248 virtual void initializePass() {} 249 250 /// ImmutablePasses are never run. 251 /// 252 bool runOnModule(Module &) { return false; } 253 254 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {} 255 explicit ImmutablePass(const void *pid) 256 : ModulePass(pid) {} 257 258 // Force out-of-line virtual method. 259 virtual ~ImmutablePass(); 260}; 261 262//===----------------------------------------------------------------------===// 263/// FunctionPass class - This class is used to implement most global 264/// optimizations. Optimizations should subclass this class if they meet the 265/// following constraints: 266/// 267/// 1. Optimizations are organized globally, i.e., a function at a time 268/// 2. Optimizing a function does not cause the addition or removal of any 269/// functions in the module 270/// 271class FunctionPass : public Pass { 272public: 273 explicit FunctionPass(intptr_t pid) : Pass(pid) {} 274 explicit FunctionPass(const void *pid) : Pass(pid) {} 275 276 /// doInitialization - Virtual method overridden by subclasses to do 277 /// any necessary per-module initialization. 278 /// 279 virtual bool doInitialization(Module &) { return false; } 280 281 /// runOnFunction - Virtual method overriden by subclasses to do the 282 /// per-function processing of the pass. 283 /// 284 virtual bool runOnFunction(Function &F) = 0; 285 286 /// doFinalization - Virtual method overriden by subclasses to do any post 287 /// processing needed after all passes have run. 288 /// 289 virtual bool doFinalization(Module &) { return false; } 290 291 /// runOnModule - On a module, we run this pass by initializing, 292 /// ronOnFunction'ing once for every function in the module, then by 293 /// finalizing. 294 /// 295 virtual bool runOnModule(Module &M); 296 297 /// run - On a function, we simply initialize, run the function, then 298 /// finalize. 299 /// 300 bool run(Function &F); 301 302 virtual void assignPassManager(PMStack &PMS, 303 PassManagerType T = PMT_FunctionPassManager); 304 305 /// Return what kind of Pass Manager can manage this pass. 306 virtual PassManagerType getPotentialPassManagerType() const { 307 return PMT_FunctionPassManager; 308 } 309}; 310 311 312 313//===----------------------------------------------------------------------===// 314/// BasicBlockPass class - This class is used to implement most local 315/// optimizations. Optimizations should subclass this class if they 316/// meet the following constraints: 317/// 1. Optimizations are local, operating on either a basic block or 318/// instruction at a time. 319/// 2. Optimizations do not modify the CFG of the contained function, or any 320/// other basic block in the function. 321/// 3. Optimizations conform to all of the constraints of FunctionPasses. 322/// 323class BasicBlockPass : public Pass { 324public: 325 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {} 326 explicit BasicBlockPass(const void *pid) : Pass(pid) {} 327 328 /// doInitialization - Virtual method overridden by subclasses to do 329 /// any necessary per-module initialization. 330 /// 331 virtual bool doInitialization(Module &) { return false; } 332 333 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 334 /// to do any necessary per-function initialization. 335 /// 336 virtual bool doInitialization(Function &) { return false; } 337 338 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 339 /// per-basicblock processing of the pass. 340 /// 341 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 342 343 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 344 /// do any post processing needed after all passes have run. 345 /// 346 virtual bool doFinalization(Function &) { return false; } 347 348 /// doFinalization - Virtual method overriden by subclasses to do any post 349 /// processing needed after all passes have run. 350 /// 351 virtual bool doFinalization(Module &) { return false; } 352 353 354 // To run this pass on a function, we simply call runOnBasicBlock once for 355 // each function. 356 // 357 bool runOnFunction(Function &F); 358 359 virtual void assignPassManager(PMStack &PMS, 360 PassManagerType T = PMT_BasicBlockPassManager); 361 362 /// Return what kind of Pass Manager can manage this pass. 363 virtual PassManagerType getPotentialPassManagerType() const { 364 return PMT_BasicBlockPassManager; 365 } 366}; 367 368/// If the user specifies the -time-passes argument on an LLVM tool command line 369/// then the value of this boolean will be true, otherwise false. 370/// @brief This is the storage for the -time-passes option. 371extern bool TimePassesIsEnabled; 372 373} // End llvm namespace 374 375// Include support files that contain important APIs commonly used by Passes, 376// but that we want to separate out to make it easier to read the header files. 377// 378#include "llvm/PassSupport.h" 379#include "llvm/PassAnalysisSupport.h" 380 381#endif 382