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 class AnalysisResolver;
52 // AnalysisID - Use the PassInfo to identify a pass...
53 typedef const PassInfo* AnalysisID;
55 /// Different types of internal pass managers. External pass managers
56 /// (PassManager and FunctionPassManager) are not represented here.
57 /// Ordering of pass manager types is important here.
58 enum PassManagerType {
60 PMT_ModulePassManager = 1, /// MPPassManager
61 PMT_CallGraphPassManager, /// CGPassManager
62 PMT_FunctionPassManager, /// FPPassManager
63 PMT_LoopPassManager, /// LPPassManager
64 PMT_BasicBlockPassManager, /// BBPassManager
68 typedef enum PassManagerType PassManagerType;
70 //===----------------------------------------------------------------------===//
71 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
72 /// interprocedural optimization or you do not fit into any of the more
73 /// constrained passes described below.
76 AnalysisResolver *Resolver; // Used to resolve analysis
79 // AnalysisImpls - This keeps track of which passes implement the interfaces
80 // that are required by the current pass (to implement getAnalysis()).
82 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
84 void operator=(const Pass&); // DO NOT IMPLEMENT
85 Pass(const Pass &); // DO NOT IMPLEMENT
87 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {}
90 /// getPassName - Return a nice clean name for a pass. This usually
91 /// implemented in terms of the name that is registered by one of the
92 /// Registration templates, but can be overloaded directly, and if nothing
93 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
94 /// intelligible name for the pass.
96 virtual const char *getPassName() const;
98 /// getPassInfo - Return the PassInfo data structure that corresponds to this
99 /// pass... If the pass has not been registered, this will return null.
101 const PassInfo *getPassInfo() const;
103 /// runPass - Run this pass, returning true if a modification was made to the
104 /// module argument. This should be implemented by all concrete subclasses.
106 virtual bool runPass(Module &M) { return false; }
107 virtual bool runPass(BasicBlock&) { return false; }
109 /// print - Print out the internal state of the pass. This is called by
110 /// Analyze to print out the contents of an analysis. Otherwise it is not
111 /// necessary to implement this method. Beware that the module pointer MAY be
112 /// null. This automatically forwards to a virtual function that does not
113 /// provide the Module* in case the analysis doesn't need it it can just be
116 virtual void print(std::ostream &O, const Module *M) const;
117 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
118 void dump() const; // dump - call print(std::cerr, 0);
120 /// Each pass is responsible for assigning a pass manager to itself.
121 /// PMS is the stack of available pass manager.
122 virtual void assignPassManager(PMStack &PMS,
123 PassManagerType T = PMT_Unknown) {}
124 /// Check if available pass managers are suitable for this pass or not.
125 virtual void preparePassManager(PMStack &PMS) {}
127 /// Return what kind of Pass Manager can manage this pass.
128 virtual PassManagerType getPotentialPassManagerType() const {
132 // Access AnalysisResolver
133 inline void setResolver(AnalysisResolver *AR) { Resolver = AR; }
134 inline AnalysisResolver *getResolver() { return Resolver; }
136 /// getAnalysisUsage - This function should be overriden by passes that need
137 /// analysis information to do their job. If a pass specifies that it uses a
138 /// particular analysis result to this function, it can then use the
139 /// getAnalysis<AnalysisType>() function, below.
141 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
142 // By default, no analysis results are used, all are invalidated.
145 /// releaseMemory() - This member can be implemented by a pass if it wants to
146 /// be able to release its memory when it is no longer needed. The default
147 /// behavior of passes is to hold onto memory for the entire duration of their
148 /// lifetime (which is the entire compile time). For pipelined passes, this
149 /// is not a big deal because that memory gets recycled every time the pass is
150 /// invoked on another program unit. For IP passes, it is more important to
151 /// free memory when it is unused.
153 /// Optionally implement this function to release pass memory when it is no
156 virtual void releaseMemory() {}
158 // dumpPassStructure - Implement the -debug-passes=PassStructure option
159 virtual void dumpPassStructure(unsigned Offset = 0);
161 template<typename AnalysisClass>
162 static const PassInfo *getClassPassInfo() {
163 return lookupPassInfo((intptr_t)&AnalysisClass::ID);
166 // lookupPassInfo - Return the pass info object for the specified pass class,
167 // or null if it is not known.
168 static const PassInfo *lookupPassInfo(intptr_t TI);
170 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
171 /// to get to the analysis information that might be around that needs to be
172 /// updated. This is different than getAnalysis in that it can fail (ie the
173 /// analysis results haven't been computed), so should only be used if you
174 /// provide the capability to update an analysis that exists. This method is
175 /// often used by transformation APIs to update analysis results for a pass
176 /// automatically as the transform is performed.
178 template<typename AnalysisType>
179 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
181 /// mustPreserveAnalysisID - This method serves the same function as
182 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
183 /// obviously cannot give you a properly typed instance of the class if you
184 /// don't have the class name available (use getAnalysisToUpdate if you do),
185 /// but it can tell you if you need to preserve the pass at least.
187 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
189 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
190 /// to the analysis information that they claim to use by overriding the
191 /// getAnalysisUsage function.
193 template<typename AnalysisType>
194 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
196 template<typename AnalysisType>
197 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
199 template<typename AnalysisType>
200 AnalysisType &getAnalysisID(const PassInfo *PI) const;
202 template<typename AnalysisType>
203 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
206 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
207 P.print(OS, 0); return OS;
210 //===----------------------------------------------------------------------===//
211 /// ModulePass class - This class is used to implement unstructured
212 /// interprocedural optimizations and analyses. ModulePasses may do anything
213 /// they want to the program.
215 class ModulePass : public Pass {
217 /// runOnModule - Virtual method overriden by subclasses to process the module
218 /// being operated on.
219 virtual bool runOnModule(Module &M) = 0;
221 virtual bool runPass(Module &M) { return runOnModule(M); }
222 virtual bool runPass(BasicBlock&) { return false; }
224 virtual void assignPassManager(PMStack &PMS,
225 PassManagerType T = PMT_ModulePassManager);
227 /// Return what kind of Pass Manager can manage this pass.
228 virtual PassManagerType getPotentialPassManagerType() const {
229 return PMT_ModulePassManager;
232 explicit ModulePass(intptr_t pid) : Pass(pid) {}
233 // Force out-of-line virtual method.
234 virtual ~ModulePass();
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.
243 class ImmutablePass : public ModulePass {
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<>.
251 virtual void initializePass() {}
253 /// ImmutablePasses are never run.
255 virtual bool runOnModule(Module &M) { return false; }
257 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
258 // Force out-of-line virtual method.
259 virtual ~ImmutablePass();
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:
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
271 class FunctionPass : public Pass {
273 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
275 /// doInitialization - Virtual method overridden by subclasses to do
276 /// any necessary per-module initialization.
278 virtual bool doInitialization(Module &M) { return false; }
280 /// runOnFunction - Virtual method overriden by subclasses to do the
281 /// per-function processing of the pass.
283 virtual bool runOnFunction(Function &F) = 0;
285 /// doFinalization - Virtual method overriden by subclasses to do any post
286 /// processing needed after all passes have run.
288 virtual bool doFinalization(Module &M) { return false; }
290 /// runOnModule - On a module, we run this pass by initializing,
291 /// ronOnFunction'ing once for every function in the module, then by
294 virtual bool runOnModule(Module &M);
296 /// run - On a function, we simply initialize, run the function, then
299 bool run(Function &F);
301 virtual void assignPassManager(PMStack &PMS,
302 PassManagerType T = PMT_FunctionPassManager);
304 /// Return what kind of Pass Manager can manage this pass.
305 virtual PassManagerType getPotentialPassManagerType() const {
306 return PMT_FunctionPassManager;
312 //===----------------------------------------------------------------------===//
313 /// BasicBlockPass class - This class is used to implement most local
314 /// optimizations. Optimizations should subclass this class if they
315 /// meet the following constraints:
316 /// 1. Optimizations are local, operating on either a basic block or
317 /// instruction at a time.
318 /// 2. Optimizations do not modify the CFG of the contained function, or any
319 /// other basic block in the function.
320 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
322 class BasicBlockPass : public Pass {
324 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
326 /// doInitialization - Virtual method overridden by subclasses to do
327 /// any necessary per-module initialization.
329 virtual bool doInitialization(Module &M) { return false; }
331 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
332 /// to do any necessary per-function initialization.
334 virtual bool doInitialization(Function &F) { return false; }
336 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
337 /// per-basicblock processing of the pass.
339 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
341 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
342 /// do any post processing needed after all passes have run.
344 virtual bool doFinalization(Function &F) { return false; }
346 /// doFinalization - Virtual method overriden by subclasses to do any post
347 /// processing needed after all passes have run.
349 virtual bool doFinalization(Module &M) { return false; }
352 // To run this pass on a function, we simply call runOnBasicBlock once for
355 bool runOnFunction(Function &F);
357 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
360 virtual bool runPass(Module &M) { return false; }
361 virtual bool runPass(BasicBlock &BB);
363 virtual void assignPassManager(PMStack &PMS,
364 PassManagerType T = PMT_BasicBlockPassManager);
366 /// Return what kind of Pass Manager can manage this pass.
367 virtual PassManagerType getPotentialPassManagerType() const {
368 return PMT_BasicBlockPassManager;
373 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
374 /// using PMStack. Each Pass implements assignPassManager() to connect itself
375 /// with appropriate manager. assignPassManager() walks PMStack to find
376 /// suitable manager.
378 /// PMStack is just a wrapper around standard deque that overrides pop() and
382 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
383 iterator begin() { return S.rbegin(); }
384 iterator end() { return S.rend(); }
386 void handleLastUserOverflow();
389 inline PMDataManager *top() { return S.back(); }
391 inline bool empty() { return S.empty(); }
395 std::deque<PMDataManager *> S;
399 /// If the user specifies the -time-passes argument on an LLVM tool command line
400 /// then the value of this boolean will be true, otherwise false.
401 /// @brief This is the storage for the -time-passes option.
402 extern bool TimePassesIsEnabled;
404 } // End llvm namespace
406 // Include support files that contain important APIs commonly used by Passes,
407 // but that we want to separate out to make it easier to read the header files.
409 #include "llvm/PassSupport.h"
410 #include "llvm/PassAnalysisSupport.h"