1 //===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
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.
8 //===----------------------------------------------------------------------===//
10 // This file defines a base class that indicates that a specified class is a
11 // transformation pass implementation.
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.
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.
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.
27 //===----------------------------------------------------------------------===//
32 #include "llvm/Support/Streams.h"
49 template<class Trait> class PassManagerT;
50 class BasicBlockPassManager;
51 class FunctionPassManagerT;
52 class ModulePassManager;
54 class AnalysisResolver;
57 // AnalysisID - Use the PassInfo to identify a pass...
58 typedef const PassInfo* AnalysisID;
60 /// Different types of internal pass managers. External pass managers
61 /// (PassManager and FunctionPassManager) are not represented here.
62 /// Ordering of pass manager types is important here.
63 enum PassManagerType {
65 PMT_ModulePassManager = 1, /// MPPassManager
66 PMT_CallGraphPassManager, /// CGPassManager
67 PMT_FunctionPassManager, /// FPPassManager
68 PMT_LoopPassManager, /// LPPassManager
69 PMT_BasicBlockPassManager /// BBPassManager
72 typedef enum PassManagerType PassManagerType;
74 //===----------------------------------------------------------------------===//
75 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
76 /// interprocedural optimization or you do not fit into any of the more
77 /// constrained passes described below.
80 AnalysisResolver *Resolver; // Used to resolve analysis
81 const PassInfo *PassInfoCache;
83 // AnalysisImpls - This keeps track of which passes implement the interfaces
84 // that are required by the current pass (to implement getAnalysis()).
86 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
88 void operator=(const Pass&); // DO NOT IMPLEMENT
89 Pass(const Pass &); // DO NOT IMPLEMENT
91 Pass() : Resolver(0), PassInfoCache(0) {}
92 virtual ~Pass() {} // Destructor is virtual so we can be subclassed
94 /// getPassName - Return a nice clean name for a pass. This usually
95 /// implemented in terms of the name that is registered by one of the
96 /// Registration templates, but can be overloaded directly, and if nothing
97 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
98 /// intelligible name for the pass.
100 virtual const char *getPassName() const;
102 /// getPassInfo - Return the PassInfo data structure that corresponds to this
103 /// pass... If the pass has not been registered, this will return null.
105 const PassInfo *getPassInfo() const;
107 /// runPass - Run this pass, returning true if a modification was made to the
108 /// module argument. This should be implemented by all concrete subclasses.
110 virtual bool runPass(Module &M) { return false; }
111 virtual bool runPass(BasicBlock&) { return false; }
113 /// print - Print out the internal state of the pass. This is called by
114 /// Analyze to print out the contents of an analysis. Otherwise it is not
115 /// necessary to implement this method. Beware that the module pointer MAY be
116 /// null. This automatically forwards to a virtual function that does not
117 /// provide the Module* in case the analysis doesn't need it it can just be
120 virtual void print(std::ostream &O, const Module *M) const;
121 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
122 void dump() const; // dump - call print(std::cerr, 0);
124 virtual void assignPassManager(PMStack &PMS,
125 PassManagerType T = PMT_Unknown) {}
126 // Access AnalysisResolver
127 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; }
128 inline AnalysisResolver *getResolver() { return Resolver; }
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.
135 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
136 // By default, no analysis results are used, all are invalidated.
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.
147 /// Optionally implement this function to release pass memory when it is no
150 virtual void releaseMemory() {}
152 // dumpPassStructure - Implement the -debug-passes=PassStructure option
153 virtual void dumpPassStructure(unsigned Offset = 0);
155 template<typename AnalysisClass>
156 static const PassInfo *getClassPassInfo() {
157 return lookupPassInfo(typeid(AnalysisClass));
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(const std::type_info &TI);
164 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
165 /// to get to the analysis information that might be around that needs to be
166 /// updated. This is different than getAnalysis in that it can fail (ie the
167 /// analysis results haven't been computed), so should only be used if you
168 /// provide the capability to update an analysis that exists. This method is
169 /// often used by transformation APIs to update analysis results for a pass
170 /// automatically as the transform is performed.
172 template<typename AnalysisType>
173 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
175 /// mustPreserveAnalysisID - This method serves the same function as
176 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
177 /// obviously cannot give you a properly typed instance of the class if you
178 /// don't have the class name available (use getAnalysisToUpdate if you do),
179 /// but it can tell you if you need to preserve the pass at least.
181 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
183 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
184 /// to the analysis information that they claim to use by overriding the
185 /// getAnalysisUsage function.
187 template<typename AnalysisType>
188 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
190 template<typename AnalysisType>
191 AnalysisType &getAnalysisID(const PassInfo *PI) const;
194 template<typename Trait> friend class PassManagerT;
195 friend class ModulePassManager;
196 friend class FunctionPassManagerT;
197 friend class BasicBlockPassManager;
200 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
201 P.print(OS, 0); return OS;
204 //===----------------------------------------------------------------------===//
205 /// ModulePass class - This class is used to implement unstructured
206 /// interprocedural optimizations and analyses. ModulePasses may do anything
207 /// they want to the program.
209 class ModulePass : public Pass {
211 /// runOnModule - Virtual method overriden by subclasses to process the module
212 /// being operated on.
213 virtual bool runOnModule(Module &M) = 0;
215 virtual bool runPass(Module &M) { return runOnModule(M); }
216 virtual bool runPass(BasicBlock&) { return false; }
218 virtual void assignPassManager(PMStack &PMS,
219 PassManagerType T = PMT_ModulePassManager);
220 // Force out-of-line virtual method.
221 virtual ~ModulePass();
225 //===----------------------------------------------------------------------===//
226 /// ImmutablePass class - This class is used to provide information that does
227 /// not need to be run. This is useful for things like target information and
228 /// "basic" versions of AnalysisGroups.
230 class ImmutablePass : public ModulePass {
232 /// initializePass - This method may be overriden by immutable passes to allow
233 /// them to perform various initialization actions they require. This is
234 /// primarily because an ImmutablePass can "require" another ImmutablePass,
235 /// and if it does, the overloaded version of initializePass may get access to
236 /// these passes with getAnalysis<>.
238 virtual void initializePass() {}
240 /// ImmutablePasses are never run.
242 virtual bool runOnModule(Module &M) { return false; }
244 // Force out-of-line virtual method.
245 virtual ~ImmutablePass();
248 //===----------------------------------------------------------------------===//
249 /// FunctionPass class - This class is used to implement most global
250 /// optimizations. Optimizations should subclass this class if they meet the
251 /// following constraints:
253 /// 1. Optimizations are organized globally, i.e., a function at a time
254 /// 2. Optimizing a function does not cause the addition or removal of any
255 /// functions in the module
257 class FunctionPass : public ModulePass {
259 /// doInitialization - Virtual method overridden by subclasses to do
260 /// any necessary per-module initialization.
262 virtual bool doInitialization(Module &M) { return false; }
264 /// runOnFunction - Virtual method overriden by subclasses to do the
265 /// per-function processing of the pass.
267 virtual bool runOnFunction(Function &F) = 0;
269 /// doFinalization - Virtual method overriden by subclasses to do any post
270 /// processing needed after all passes have run.
272 virtual bool doFinalization(Module &M) { return false; }
274 /// runOnModule - On a module, we run this pass by initializing,
275 /// ronOnFunction'ing once for every function in the module, then by
278 virtual bool runOnModule(Module &M);
280 /// run - On a function, we simply initialize, run the function, then
283 bool run(Function &F);
285 virtual void assignPassManager(PMStack &PMS,
286 PassManagerType T = PMT_FunctionPassManager);
291 //===----------------------------------------------------------------------===//
292 /// BasicBlockPass class - This class is used to implement most local
293 /// optimizations. Optimizations should subclass this class if they
294 /// meet the following constraints:
295 /// 1. Optimizations are local, operating on either a basic block or
296 /// instruction at a time.
297 /// 2. Optimizations do not modify the CFG of the contained function, or any
298 /// other basic block in the function.
299 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
301 class BasicBlockPass : public FunctionPass {
303 /// doInitialization - Virtual method overridden by subclasses to do
304 /// any necessary per-module initialization.
306 virtual bool doInitialization(Module &M) { return false; }
308 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
309 /// to do any necessary per-function initialization.
311 virtual bool doInitialization(Function &F) { return false; }
313 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
314 /// per-basicblock processing of the pass.
316 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
318 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
319 /// do any post processing needed after all passes have run.
321 virtual bool doFinalization(Function &F) { return false; }
323 /// doFinalization - Virtual method overriden by subclasses to do any post
324 /// processing needed after all passes have run.
326 virtual bool doFinalization(Module &M) { return false; }
329 // To run this pass on a function, we simply call runOnBasicBlock once for
332 bool runOnFunction(Function &F);
334 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
337 virtual bool runPass(Module &M) { return false; }
338 virtual bool runPass(BasicBlock &BB);
340 virtual void assignPassManager(PMStack &PMS,
341 PassManagerType T = PMT_BasicBlockPassManager);
345 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
346 /// using PMStack. Each Pass implements assignPassManager() to connect itself
347 /// with appropriate manager. assignPassManager() walks PMStack to find
348 /// suitable manager.
350 /// PMStack is just a wrapper around standard deque that overrides pop() and
354 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
355 iterator begin() { return S.rbegin(); }
356 iterator end() { return S.rend(); }
358 void handleLastUserOverflow();
361 inline PMDataManager *top() { return S.back(); }
363 inline bool empty() { return S.empty(); }
367 std::deque<PMDataManager *> S;
371 /// If the user specifies the -time-passes argument on an LLVM tool command line
372 /// then the value of this boolean will be true, otherwise false.
373 /// @brief This is the storage for the -time-passes option.
374 extern bool TimePassesIsEnabled;
376 } // End llvm namespace
378 // Include support files that contain important APIs commonly used by Passes,
379 // but that we want to separate out to make it easier to read the header files.
381 #include "llvm/PassSupport.h"
382 #include "llvm/PassAnalysisSupport.h"