Pass.h revision cde53d3c1e9d6a2add5de847b44818fbb1d69c20
1//===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source 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/Streams.h" 33#include <vector> 34#include <map> 35#include <iosfwd> 36#include <typeinfo> 37#include <cassert> 38 39namespace llvm { 40 41class Value; 42class BasicBlock; 43class Function; 44class Module; 45class AnalysisUsage; 46class PassInfo; 47class ImmutablePass; 48template<class Trait> class PassManagerT; 49class BasicBlockPassManager; 50class FunctionPassManagerT; 51class ModulePassManager; 52class AnalysisResolver; 53 54// AnalysisID - Use the PassInfo to identify a pass... 55typedef const PassInfo* AnalysisID; 56 57//===----------------------------------------------------------------------===// 58/// Pass interface - Implemented by all 'passes'. Subclass this if you are an 59/// interprocedural optimization or you do not fit into any of the more 60/// constrained passes described below. 61/// 62class Pass { 63 AnalysisResolver *Resolver; // Used to resolve analysis 64 const PassInfo *PassInfoCache; 65 66 // AnalysisImpls - This keeps track of which passes implement the interfaces 67 // that are required by the current pass (to implement getAnalysis()). 68 // 69 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls; 70 71 void operator=(const Pass&); // DO NOT IMPLEMENT 72 Pass(const Pass &); // DO NOT IMPLEMENT 73public: 74 Pass() : Resolver(0), PassInfoCache(0) {} 75 virtual ~Pass() {} // Destructor is virtual so we can be subclassed 76 77 /// getPassName - Return a nice clean name for a pass. This usually 78 /// implemented in terms of the name that is registered by one of the 79 /// Registration templates, but can be overloaded directly, and if nothing 80 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT 81 /// intelligible name for the pass. 82 /// 83 virtual const char *getPassName() const; 84 85 /// getPassInfo - Return the PassInfo data structure that corresponds to this 86 /// pass... If the pass has not been registered, this will return null. 87 /// 88 const PassInfo *getPassInfo() const; 89 90 /// runPass - Run this pass, returning true if a modification was made to the 91 /// module argument. This should be implemented by all concrete subclasses. 92 /// 93 virtual bool runPass(Module &M) { return false; } 94 virtual bool runPass(BasicBlock&) { return false; } 95 96 /// print - Print out the internal state of the pass. This is called by 97 /// Analyze to print out the contents of an analysis. Otherwise it is not 98 /// necessary to implement this method. Beware that the module pointer MAY be 99 /// null. This automatically forwards to a virtual function that does not 100 /// provide the Module* in case the analysis doesn't need it it can just be 101 /// ignored. 102 /// 103 virtual void print(std::ostream &O, const Module *M) const; 104 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); } 105 void dump() const; // dump - call print(std::cerr, 0); 106 107 // Access AnalysisResolver 108 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; } 109 inline AnalysisResolver *getResolver() { return Resolver; } 110 111 /// getAnalysisUsage - This function should be overriden by passes that need 112 /// analysis information to do their job. If a pass specifies that it uses a 113 /// particular analysis result to this function, it can then use the 114 /// getAnalysis<AnalysisType>() function, below. 115 /// 116 virtual void getAnalysisUsage(AnalysisUsage &Info) const { 117 // By default, no analysis results are used, all are invalidated. 118 } 119 120 /// releaseMemory() - This member can be implemented by a pass if it wants to 121 /// be able to release its memory when it is no longer needed. The default 122 /// behavior of passes is to hold onto memory for the entire duration of their 123 /// lifetime (which is the entire compile time). For pipelined passes, this 124 /// is not a big deal because that memory gets recycled every time the pass is 125 /// invoked on another program unit. For IP passes, it is more important to 126 /// free memory when it is unused. 127 /// 128 /// Optionally implement this function to release pass memory when it is no 129 /// longer used. 130 /// 131 virtual void releaseMemory() {} 132 133 // dumpPassStructure - Implement the -debug-passes=PassStructure option 134 virtual void dumpPassStructure(unsigned Offset = 0); 135 136 137 // getPassInfo - Static method to get the pass information from a class name. 138 template<typename AnalysisClass> 139 static const PassInfo *getClassPassInfo() { 140 return lookupPassInfo(typeid(AnalysisClass)); 141 } 142 143 // lookupPassInfo - Return the pass info object for the specified pass class, 144 // or null if it is not known. 145 static const PassInfo *lookupPassInfo(const std::type_info &TI); 146 147 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses 148 /// to get to the analysis information that might be around that needs to be 149 /// updated. This is different than getAnalysis in that it can fail (ie the 150 /// analysis results haven't been computed), so should only be used if you 151 /// provide the capability to update an analysis that exists. This method is 152 /// often used by transformation APIs to update analysis results for a pass 153 /// automatically as the transform is performed. 154 /// 155 template<typename AnalysisType> 156 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h 157 158 /// mustPreserveAnalysisID - This method serves the same function as 159 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This 160 /// obviously cannot give you a properly typed instance of the class if you 161 /// don't have the class name available (use getAnalysisToUpdate if you do), 162 /// but it can tell you if you need to preserve the pass at least. 163 /// 164 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const; 165 166 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get 167 /// to the analysis information that they claim to use by overriding the 168 /// getAnalysisUsage function. 169 /// 170 template<typename AnalysisType> 171 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h 172 173 template<typename AnalysisType> 174 AnalysisType &getAnalysisID(const PassInfo *PI) const; 175 176private: 177 template<typename Trait> friend class PassManagerT; 178 friend class ModulePassManager; 179 friend class FunctionPassManagerT; 180 friend class BasicBlockPassManager; 181}; 182 183inline std::ostream &operator<<(std::ostream &OS, const Pass &P) { 184 P.print(OS, 0); return OS; 185} 186 187//===----------------------------------------------------------------------===// 188/// ModulePass class - This class is used to implement unstructured 189/// interprocedural optimizations and analyses. ModulePasses may do anything 190/// they want to the program. 191/// 192class ModulePass : public Pass { 193public: 194 /// runOnModule - Virtual method overriden by subclasses to process the module 195 /// being operated on. 196 virtual bool runOnModule(Module &M) = 0; 197 198 virtual bool runPass(Module &M) { return runOnModule(M); } 199 virtual bool runPass(BasicBlock&) { return false; } 200 201 // Force out-of-line virtual method. 202 virtual ~ModulePass(); 203}; 204 205 206//===----------------------------------------------------------------------===// 207/// ImmutablePass class - This class is used to provide information that does 208/// not need to be run. This is useful for things like target information and 209/// "basic" versions of AnalysisGroups. 210/// 211class ImmutablePass : public ModulePass { 212public: 213 /// initializePass - This method may be overriden by immutable passes to allow 214 /// them to perform various initialization actions they require. This is 215 /// primarily because an ImmutablePass can "require" another ImmutablePass, 216 /// and if it does, the overloaded version of initializePass may get access to 217 /// these passes with getAnalysis<>. 218 /// 219 virtual void initializePass() {} 220 221 /// ImmutablePasses are never run. 222 /// 223 virtual bool runOnModule(Module &M) { return false; } 224 225 // Force out-of-line virtual method. 226 virtual ~ImmutablePass(); 227}; 228 229//===----------------------------------------------------------------------===// 230/// FunctionPass class - This class is used to implement most global 231/// optimizations. Optimizations should subclass this class if they meet the 232/// following constraints: 233/// 234/// 1. Optimizations are organized globally, i.e., a function at a time 235/// 2. Optimizing a function does not cause the addition or removal of any 236/// functions in the module 237/// 238class FunctionPass : public ModulePass { 239public: 240 /// doInitialization - Virtual method overridden by subclasses to do 241 /// any necessary per-module initialization. 242 /// 243 virtual bool doInitialization(Module &M) { return false; } 244 245 /// runOnFunction - Virtual method overriden by subclasses to do the 246 /// per-function processing of the pass. 247 /// 248 virtual bool runOnFunction(Function &F) = 0; 249 250 /// doFinalization - Virtual method overriden by subclasses to do any post 251 /// processing needed after all passes have run. 252 /// 253 virtual bool doFinalization(Module &M) { return false; } 254 255 /// runOnModule - On a module, we run this pass by initializing, 256 /// ronOnFunction'ing once for every function in the module, then by 257 /// finalizing. 258 /// 259 virtual bool runOnModule(Module &M); 260 261 /// run - On a function, we simply initialize, run the function, then 262 /// finalize. 263 /// 264 bool run(Function &F); 265 266}; 267 268 269 270//===----------------------------------------------------------------------===// 271/// BasicBlockPass class - This class is used to implement most local 272/// optimizations. Optimizations should subclass this class if they 273/// meet the following constraints: 274/// 1. Optimizations are local, operating on either a basic block or 275/// instruction at a time. 276/// 2. Optimizations do not modify the CFG of the contained function, or any 277/// other basic block in the function. 278/// 3. Optimizations conform to all of the constraints of FunctionPasses. 279/// 280class BasicBlockPass : public FunctionPass { 281public: 282 /// doInitialization - Virtual method overridden by subclasses to do 283 /// any necessary per-module initialization. 284 /// 285 virtual bool doInitialization(Module &M) { return false; } 286 287 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses 288 /// to do any necessary per-function initialization. 289 /// 290 virtual bool doInitialization(Function &F) { return false; } 291 292 /// runOnBasicBlock - Virtual method overriden by subclasses to do the 293 /// per-basicblock processing of the pass. 294 /// 295 virtual bool runOnBasicBlock(BasicBlock &BB) = 0; 296 297 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to 298 /// do any post processing needed after all passes have run. 299 /// 300 virtual bool doFinalization(Function &F) { return false; } 301 302 /// doFinalization - Virtual method overriden by subclasses to do any post 303 /// processing needed after all passes have run. 304 /// 305 virtual bool doFinalization(Module &M) { return false; } 306 307 308 // To run this pass on a function, we simply call runOnBasicBlock once for 309 // each function. 310 // 311 bool runOnFunction(Function &F); 312 313 /// To run directly on the basic block, we initialize, runOnBasicBlock, then 314 /// finalize. 315 /// 316 virtual bool runPass(Module &M) { return false; } 317 virtual bool runPass(BasicBlock &BB); 318 319}; 320 321/// If the user specifies the -time-passes argument on an LLVM tool command line 322/// then the value of this boolean will be true, otherwise false. 323/// @brief This is the storage for the -time-passes option. 324extern bool TimePassesIsEnabled; 325 326} // End llvm namespace 327 328// Include support files that contain important APIs commonly used by Passes, 329// but that we want to separate out to make it easier to read the header files. 330// 331#include "llvm/PassSupport.h" 332#include "llvm/PassAnalysisSupport.h" 333 334#endif 335