Pass.h revision 5e664b8f7c5ba877058a3a1cdfcce8e6b7388a6a
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 /// getAdjustedAnalysisPointer - This method is used when a pass implements 149 /// an analysis interface through multiple inheritance. If needed, it should 150 /// override this to adjust the this pointer as needed for the specified pass 151 /// info. 152 virtual void *getAdjustedAnalysisPointer(const PassInfo *PI) { 153 return this; 154 } 155 virtual ImmutablePass *getAsImmutablePass() { return 0; } 156 157 /// verifyAnalysis() - This member can be implemented by a analysis pass to 158 /// check state of analysis information. 159 virtual void verifyAnalysis() const; 160 161 // dumpPassStructure - Implement the -debug-passes=PassStructure option 162 virtual void dumpPassStructure(unsigned Offset = 0); 163 164 template<typename AnalysisClass> 165 static const PassInfo *getClassPassInfo() { 166 return lookupPassInfo(intptr_t(&AnalysisClass::ID)); 167 } 168 169 // lookupPassInfo - Return the pass info object for the specified pass class, 170 // or null if it is not known. 171 static const PassInfo *lookupPassInfo(intptr_t TI); 172 173 // lookupPassInfo - Return the pass info object for the pass with the given 174 // argument string, or null if it is not known. 175 static const PassInfo *lookupPassInfo(StringRef Arg); 176 177 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to 178 /// get analysis information that might be around, for example to update it. 179 /// This is different than getAnalysis in that it can fail (if the analysis 180 /// results haven't been computed), so should only be used if you can handle 181 /// the case when the analysis is not available. This method is often used by 182 /// transformation APIs to update analysis results for a pass automatically as 183 /// the transform is performed. 184 /// 185 template<typename AnalysisType> AnalysisType * 186 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h 187 188 /// mustPreserveAnalysisID - This method serves the same function as 189 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This 190 /// obviously cannot give you a properly typed instance of the class if you 191 /// don't have the class name available (use getAnalysisIfAvailable if you 192 /// do), but it can tell you if you need to preserve the pass at least. 193 /// 194 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 195 196 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 197 /// to the analysis information that they claim to use by overriding the 198 /// getAnalysisUsage function. 199 /// 200 template<typename AnalysisType> 201 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 202 203 template<typename AnalysisType> 204 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h 205 206 template<typename AnalysisType> 207 AnalysisType &getAnalysisID(const PassInfo *PI) const; 208 209 template<typename AnalysisType> 210 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F); 211}; 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; 230 231 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 virtual ImmutablePass *getAsImmutablePass() { return this; } 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 &); 285 286 /// runOnFunction - Virtual method overriden by subclasses to do the 287 /// per-function processing of the pass. 288 /// 289 virtual bool runOnFunction(Function &F) = 0; 290 291 /// doFinalization - Virtual method overriden by subclasses to do any post 292 /// processing needed after all passes have run. 293 /// 294 virtual bool doFinalization(Module &); 295 296 /// runOnModule - On a module, we run this pass by initializing, 297 /// ronOnFunction'ing once for every function in the module, then by 298 /// finalizing. 299 /// 300 virtual bool runOnModule(Module &M); 301 302 /// run - On a function, we simply initialize, run the function, then 303 /// finalize. 304 /// 305 bool run(Function &F); 306 307 virtual void assignPassManager(PMStack &PMS, 308 PassManagerType T = PMT_FunctionPassManager); 309 310 /// Return what kind of Pass Manager can manage this pass. 311 virtual PassManagerType getPotentialPassManagerType() const; 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 &); 335 336 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 337 /// to do any necessary per-function initialization. 338 /// 339 virtual bool doInitialization(Function &); 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 &); 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 &); 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}; 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