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) {
134 assert (!Resolver && "Resolver is already set");
137 inline AnalysisResolver *getResolver() {
138 assert (Resolver && "Resolver is not set");
142 /// getAnalysisUsage - This function should be overriden by passes that need
143 /// analysis information to do their job. If a pass specifies that it uses a
144 /// particular analysis result to this function, it can then use the
145 /// getAnalysis<AnalysisType>() function, below.
147 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
148 // By default, no analysis results are used, all are invalidated.
151 /// releaseMemory() - This member can be implemented by a pass if it wants to
152 /// be able to release its memory when it is no longer needed. The default
153 /// behavior of passes is to hold onto memory for the entire duration of their
154 /// lifetime (which is the entire compile time). For pipelined passes, this
155 /// is not a big deal because that memory gets recycled every time the pass is
156 /// invoked on another program unit. For IP passes, it is more important to
157 /// free memory when it is unused.
159 /// Optionally implement this function to release pass memory when it is no
162 virtual void releaseMemory() {}
164 /// verifyAnalysis() - This member can be implemented by a analysis pass to
165 /// check state of analysis information.
166 virtual void verifyAnalysis() const {}
168 // dumpPassStructure - Implement the -debug-passes=PassStructure option
169 virtual void dumpPassStructure(unsigned Offset = 0);
171 template<typename AnalysisClass>
172 static const PassInfo *getClassPassInfo() {
173 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
176 // lookupPassInfo - Return the pass info object for the specified pass class,
177 // or null if it is not known.
178 static const PassInfo *lookupPassInfo(intptr_t TI);
180 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
181 /// to get to the analysis information that might be around that needs to be
182 /// updated. This is different than getAnalysis in that it can fail (ie the
183 /// analysis results haven't been computed), so should only be used if you
184 /// provide the capability to update an analysis that exists. This method is
185 /// often used by transformation APIs to update analysis results for a pass
186 /// automatically as the transform is performed.
188 template<typename AnalysisType>
189 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
191 /// mustPreserveAnalysisID - This method serves the same function as
192 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
193 /// obviously cannot give you a properly typed instance of the class if you
194 /// don't have the class name available (use getAnalysisToUpdate if you do),
195 /// but it can tell you if you need to preserve the pass at least.
197 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
199 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
200 /// to the analysis information that they claim to use by overriding the
201 /// getAnalysisUsage function.
203 template<typename AnalysisType>
204 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
206 template<typename AnalysisType>
207 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
209 template<typename AnalysisType>
210 AnalysisType &getAnalysisID(const PassInfo *PI) const;
212 template<typename AnalysisType>
213 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
216 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
217 P.print(OS, 0); return OS;
220 //===----------------------------------------------------------------------===//
221 /// ModulePass class - This class is used to implement unstructured
222 /// interprocedural optimizations and analyses. ModulePasses may do anything
223 /// they want to the program.
225 class ModulePass : public Pass {
227 /// runOnModule - Virtual method overriden by subclasses to process the module
228 /// being operated on.
229 virtual bool runOnModule(Module &M) = 0;
231 virtual bool runPass(Module &M) { return runOnModule(M); }
232 virtual bool runPass(BasicBlock&) { return false; }
234 virtual void assignPassManager(PMStack &PMS,
235 PassManagerType T = PMT_ModulePassManager);
237 /// Return what kind of Pass Manager can manage this pass.
238 virtual PassManagerType getPotentialPassManagerType() const {
239 return PMT_ModulePassManager;
242 explicit ModulePass(intptr_t pid) : Pass(pid) {}
243 // Force out-of-line virtual method.
244 virtual ~ModulePass();
248 //===----------------------------------------------------------------------===//
249 /// ImmutablePass class - This class is used to provide information that does
250 /// not need to be run. This is useful for things like target information and
251 /// "basic" versions of AnalysisGroups.
253 class ImmutablePass : public ModulePass {
255 /// initializePass - This method may be overriden by immutable passes to allow
256 /// them to perform various initialization actions they require. This is
257 /// primarily because an ImmutablePass can "require" another ImmutablePass,
258 /// and if it does, the overloaded version of initializePass may get access to
259 /// these passes with getAnalysis<>.
261 virtual void initializePass() {}
263 /// ImmutablePasses are never run.
265 bool runOnModule(Module &M) { return false; }
267 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
268 // Force out-of-line virtual method.
269 virtual ~ImmutablePass();
272 //===----------------------------------------------------------------------===//
273 /// FunctionPass class - This class is used to implement most global
274 /// optimizations. Optimizations should subclass this class if they meet the
275 /// following constraints:
277 /// 1. Optimizations are organized globally, i.e., a function at a time
278 /// 2. Optimizing a function does not cause the addition or removal of any
279 /// functions in the module
281 class FunctionPass : public Pass {
283 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
285 /// doInitialization - Virtual method overridden by subclasses to do
286 /// any necessary per-module initialization.
288 virtual bool doInitialization(Module &M) { return false; }
290 /// runOnFunction - Virtual method overriden by subclasses to do the
291 /// per-function processing of the pass.
293 virtual bool runOnFunction(Function &F) = 0;
295 /// doFinalization - Virtual method overriden by subclasses to do any post
296 /// processing needed after all passes have run.
298 virtual bool doFinalization(Module &M) { return false; }
300 /// runOnModule - On a module, we run this pass by initializing,
301 /// ronOnFunction'ing once for every function in the module, then by
304 virtual bool runOnModule(Module &M);
306 /// run - On a function, we simply initialize, run the function, then
309 bool run(Function &F);
311 virtual void assignPassManager(PMStack &PMS,
312 PassManagerType T = PMT_FunctionPassManager);
314 /// Return what kind of Pass Manager can manage this pass.
315 virtual PassManagerType getPotentialPassManagerType() const {
316 return PMT_FunctionPassManager;
322 //===----------------------------------------------------------------------===//
323 /// BasicBlockPass class - This class is used to implement most local
324 /// optimizations. Optimizations should subclass this class if they
325 /// meet the following constraints:
326 /// 1. Optimizations are local, operating on either a basic block or
327 /// instruction at a time.
328 /// 2. Optimizations do not modify the CFG of the contained function, or any
329 /// other basic block in the function.
330 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
332 class BasicBlockPass : public Pass {
334 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
336 /// doInitialization - Virtual method overridden by subclasses to do
337 /// any necessary per-module initialization.
339 virtual bool doInitialization(Module &M) { return false; }
341 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
342 /// to do any necessary per-function initialization.
344 virtual bool doInitialization(Function &F) { return false; }
346 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
347 /// per-basicblock processing of the pass.
349 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
351 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
352 /// do any post processing needed after all passes have run.
354 virtual bool doFinalization(Function &F) { return false; }
356 /// doFinalization - Virtual method overriden by subclasses to do any post
357 /// processing needed after all passes have run.
359 virtual bool doFinalization(Module &M) { return false; }
362 // To run this pass on a function, we simply call runOnBasicBlock once for
365 bool runOnFunction(Function &F);
367 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
370 virtual bool runPass(Module &M) { return false; }
371 virtual bool runPass(BasicBlock &BB);
373 virtual void assignPassManager(PMStack &PMS,
374 PassManagerType T = PMT_BasicBlockPassManager);
376 /// Return what kind of Pass Manager can manage this pass.
377 virtual PassManagerType getPotentialPassManagerType() const {
378 return PMT_BasicBlockPassManager;
383 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
384 /// using PMStack. Each Pass implements assignPassManager() to connect itself
385 /// with appropriate manager. assignPassManager() walks PMStack to find
386 /// suitable manager.
388 /// PMStack is just a wrapper around standard deque that overrides pop() and
392 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
393 iterator begin() { return S.rbegin(); }
394 iterator end() { return S.rend(); }
396 void handleLastUserOverflow();
399 inline PMDataManager *top() { return S.back(); }
401 inline bool empty() { return S.empty(); }
405 std::deque<PMDataManager *> S;
409 /// If the user specifies the -time-passes argument on an LLVM tool command line
410 /// then the value of this boolean will be true, otherwise false.
411 /// @brief This is the storage for the -time-passes option.
412 extern bool TimePassesIsEnabled;
414 } // End llvm namespace
416 // Include support files that contain important APIs commonly used by Passes,
417 // but that we want to separate out to make it easier to read the header files.
419 #include "llvm/PassSupport.h"
420 #include "llvm/PassAnalysisSupport.h"