1 //===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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/System/DataTypes.h"
46 class AnalysisResolver;
51 // AnalysisID - Use the PassInfo to identify a pass...
52 typedef const PassInfo* AnalysisID;
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.
57 enum PassManagerType {
59 PMT_ModulePassManager = 1, ///< MPPassManager
60 PMT_CallGraphPassManager, ///< CGPassManager
61 PMT_FunctionPassManager, ///< FPPassManager
62 PMT_LoopPassManager, ///< LPPassManager
63 PMT_BasicBlockPassManager, ///< BBPassManager
67 // Different types of passes.
77 //===----------------------------------------------------------------------===//
78 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
79 /// interprocedural optimization or you do not fit into any of the more
80 /// constrained passes described below.
83 AnalysisResolver *Resolver; // Used to resolve analysis
86 void operator=(const Pass&); // DO NOT IMPLEMENT
87 Pass(const Pass &); // DO NOT IMPLEMENT
90 explicit Pass(PassKind K, intptr_t pid) : Resolver(0), PassID(pid), Kind(K) {
91 assert(pid && "pid cannot be 0");
93 explicit Pass(PassKind K, const void *pid)
94 : Resolver(0), PassID((intptr_t)pid), Kind(K) {
95 assert(pid && "pid cannot be 0");
100 PassKind getPassKind() const { return Kind; }
102 /// getPassName - Return a nice clean name for a pass. This usually
103 /// implemented in terms of the name that is registered by one of the
104 /// Registration templates, but can be overloaded directly.
106 virtual const char *getPassName() const;
108 /// getPassInfo - Return the PassInfo data structure that corresponds to this
109 /// pass... If the pass has not been registered, this will return null.
111 const PassInfo *getPassInfo() const;
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(raw_ostream &O, const Module *M) const;
121 void dump() const; // dump - Print to stderr.
123 /// Each pass is responsible for assigning a pass manager to itself.
124 /// PMS is the stack of available pass manager.
125 virtual void assignPassManager(PMStack &,
126 PassManagerType = PMT_Unknown) {}
127 /// Check if available pass managers are suitable for this pass or not.
128 virtual void preparePassManager(PMStack &);
130 /// Return what kind of Pass Manager can manage this pass.
131 virtual PassManagerType getPotentialPassManagerType() const;
133 // Access AnalysisResolver
134 inline void setResolver(AnalysisResolver *AR) {
135 assert(!Resolver && "Resolver is already set");
138 inline AnalysisResolver *getResolver() {
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 &) const;
149 /// releaseMemory() - This member can be implemented by a pass if it wants to
150 /// be able to release its memory when it is no longer needed. The default
151 /// behavior of passes is to hold onto memory for the entire duration of their
152 /// lifetime (which is the entire compile time). For pipelined passes, this
153 /// is not a big deal because that memory gets recycled every time the pass is
154 /// invoked on another program unit. For IP passes, it is more important to
155 /// free memory when it is unused.
157 /// Optionally implement this function to release pass memory when it is no
160 virtual void releaseMemory();
162 /// getAdjustedAnalysisPointer - This method is used when a pass implements
163 /// an analysis interface through multiple inheritance. If needed, it should
164 /// override this to adjust the this pointer as needed for the specified pass
166 virtual void *getAdjustedAnalysisPointer(const PassInfo *) {
169 virtual ImmutablePass *getAsImmutablePass() { return 0; }
170 virtual PMDataManager *getAsPMDataManager() { return 0; }
172 /// verifyAnalysis() - This member can be implemented by a analysis pass to
173 /// check state of analysis information.
174 virtual void verifyAnalysis() const;
176 // dumpPassStructure - Implement the -debug-passes=PassStructure option
177 virtual void dumpPassStructure(unsigned Offset = 0);
179 template<typename AnalysisClass>
180 static const PassInfo *getClassPassInfo() {
181 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
184 // lookupPassInfo - Return the pass info object for the specified pass class,
185 // or null if it is not known.
186 static const PassInfo *lookupPassInfo(intptr_t TI);
188 // lookupPassInfo - Return the pass info object for the pass with the given
189 // argument string, or null if it is not known.
190 static const PassInfo *lookupPassInfo(StringRef Arg);
192 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
193 /// get analysis information that might be around, for example to update it.
194 /// This is different than getAnalysis in that it can fail (if the analysis
195 /// results haven't been computed), so should only be used if you can handle
196 /// the case when the analysis is not available. This method is often used by
197 /// transformation APIs to update analysis results for a pass automatically as
198 /// the transform is performed.
200 template<typename AnalysisType> AnalysisType *
201 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
203 /// mustPreserveAnalysisID - This method serves the same function as
204 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
205 /// obviously cannot give you a properly typed instance of the class if you
206 /// don't have the class name available (use getAnalysisIfAvailable if you
207 /// do), but it can tell you if you need to preserve the pass at least.
209 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
211 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
212 /// to the analysis information that they claim to use by overriding the
213 /// getAnalysisUsage function.
215 template<typename AnalysisType>
216 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
218 template<typename AnalysisType>
219 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h
221 template<typename AnalysisType>
222 AnalysisType &getAnalysisID(const PassInfo *PI) const;
224 template<typename AnalysisType>
225 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
229 //===----------------------------------------------------------------------===//
230 /// ModulePass class - This class is used to implement unstructured
231 /// interprocedural optimizations and analyses. ModulePasses may do anything
232 /// they want to the program.
234 class ModulePass : public Pass {
236 /// runOnModule - Virtual method overriden by subclasses to process the module
237 /// being operated on.
238 virtual bool runOnModule(Module &M) = 0;
240 virtual void assignPassManager(PMStack &PMS,
241 PassManagerType T = PMT_ModulePassManager);
243 /// Return what kind of Pass Manager can manage this pass.
244 virtual PassManagerType getPotentialPassManagerType() const;
246 explicit ModulePass(intptr_t pid) : Pass(PT_Module, pid) {}
247 explicit ModulePass(const void *pid) : Pass(PT_Module, pid) {}
248 // Force out-of-line virtual method.
249 virtual ~ModulePass();
253 //===----------------------------------------------------------------------===//
254 /// ImmutablePass class - This class is used to provide information that does
255 /// not need to be run. This is useful for things like target information and
256 /// "basic" versions of AnalysisGroups.
258 class ImmutablePass : public ModulePass {
260 /// initializePass - This method may be overriden by immutable passes to allow
261 /// them to perform various initialization actions they require. This is
262 /// primarily because an ImmutablePass can "require" another ImmutablePass,
263 /// and if it does, the overloaded version of initializePass may get access to
264 /// these passes with getAnalysis<>.
266 virtual void initializePass();
268 virtual ImmutablePass *getAsImmutablePass() { return this; }
270 /// ImmutablePasses are never run.
272 bool runOnModule(Module &) { return false; }
274 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
275 explicit ImmutablePass(const void *pid)
278 // Force out-of-line virtual method.
279 virtual ~ImmutablePass();
282 //===----------------------------------------------------------------------===//
283 /// FunctionPass class - This class is used to implement most global
284 /// optimizations. Optimizations should subclass this class if they meet the
285 /// following constraints:
287 /// 1. Optimizations are organized globally, i.e., a function at a time
288 /// 2. Optimizing a function does not cause the addition or removal of any
289 /// functions in the module
291 class FunctionPass : public Pass {
293 explicit FunctionPass(intptr_t pid) : Pass(PT_Function, pid) {}
294 explicit FunctionPass(const void *pid) : Pass(PT_Function, pid) {}
296 /// doInitialization - Virtual method overridden by subclasses to do
297 /// any necessary per-module initialization.
299 virtual bool doInitialization(Module &);
301 /// runOnFunction - Virtual method overriden by subclasses to do the
302 /// per-function processing of the pass.
304 virtual bool runOnFunction(Function &F) = 0;
306 /// doFinalization - Virtual method overriden by subclasses to do any post
307 /// processing needed after all passes have run.
309 virtual bool doFinalization(Module &);
311 /// runOnModule - On a module, we run this pass by initializing,
312 /// ronOnFunction'ing once for every function in the module, then by
315 virtual bool runOnModule(Module &M);
317 /// run - On a function, we simply initialize, run the function, then
320 bool run(Function &F);
322 virtual void assignPassManager(PMStack &PMS,
323 PassManagerType T = PMT_FunctionPassManager);
325 /// Return what kind of Pass Manager can manage this pass.
326 virtual PassManagerType getPotentialPassManagerType() const;
331 //===----------------------------------------------------------------------===//
332 /// BasicBlockPass class - This class is used to implement most local
333 /// optimizations. Optimizations should subclass this class if they
334 /// meet the following constraints:
335 /// 1. Optimizations are local, operating on either a basic block or
336 /// instruction at a time.
337 /// 2. Optimizations do not modify the CFG of the contained function, or any
338 /// other basic block in the function.
339 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
341 class BasicBlockPass : public Pass {
343 explicit BasicBlockPass(intptr_t pid) : Pass(PT_BasicBlock, pid) {}
344 explicit BasicBlockPass(const void *pid) : Pass(PT_BasicBlock, pid) {}
346 /// doInitialization - Virtual method overridden by subclasses to do
347 /// any necessary per-module initialization.
349 virtual bool doInitialization(Module &);
351 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
352 /// to do any necessary per-function initialization.
354 virtual bool doInitialization(Function &);
356 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
357 /// per-basicblock processing of the pass.
359 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
361 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
362 /// do any post processing needed after all passes have run.
364 virtual bool doFinalization(Function &);
366 /// doFinalization - Virtual method overriden by subclasses to do any post
367 /// processing needed after all passes have run.
369 virtual bool doFinalization(Module &);
372 // To run this pass on a function, we simply call runOnBasicBlock once for
375 bool runOnFunction(Function &F);
377 virtual void assignPassManager(PMStack &PMS,
378 PassManagerType T = PMT_BasicBlockPassManager);
380 /// Return what kind of Pass Manager can manage this pass.
381 virtual PassManagerType getPotentialPassManagerType() const;
384 /// If the user specifies the -time-passes argument on an LLVM tool command line
385 /// then the value of this boolean will be true, otherwise false.
386 /// @brief This is the storage for the -time-passes option.
387 extern bool TimePassesIsEnabled;
389 } // End llvm namespace
391 // Include support files that contain important APIs commonly used by Passes,
392 // but that we want to separate out to make it easier to read the header files.
394 #include "llvm/PassSupport.h"
395 #include "llvm/PassAnalysisSupport.h"