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"
47 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 // Different types of passes.
78 //===----------------------------------------------------------------------===//
79 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
80 /// interprocedural optimization or you do not fit into any of the more
81 /// constrained passes described below.
84 AnalysisResolver *Resolver; // Used to resolve analysis
87 void operator=(const Pass&); // DO NOT IMPLEMENT
88 Pass(const Pass &); // DO NOT IMPLEMENT
91 explicit Pass(PassKind K, intptr_t pid) : Resolver(0), PassID(pid), Kind(K) {
92 assert(pid && "pid cannot be 0");
94 explicit Pass(PassKind K, const void *pid)
95 : Resolver(0), PassID((intptr_t)pid), Kind(K) {
96 assert(pid && "pid cannot be 0");
101 PassKind getPassKind() const { return Kind; }
103 /// getPassName - Return a nice clean name for a pass. This usually
104 /// implemented in terms of the name that is registered by one of the
105 /// Registration templates, but can be overloaded directly.
107 virtual const char *getPassName() const;
109 /// getPassInfo - Return the PassInfo data structure that corresponds to this
110 /// pass... If the pass has not been registered, this will return null.
112 const PassInfo *getPassInfo() const;
114 /// print - Print out the internal state of the pass. This is called by
115 /// Analyze to print out the contents of an analysis. Otherwise it is not
116 /// necessary to implement this method. Beware that the module pointer MAY be
117 /// null. This automatically forwards to a virtual function that does not
118 /// provide the Module* in case the analysis doesn't need it it can just be
121 virtual void print(raw_ostream &O, const Module *M) const;
122 void dump() const; // dump - Print to stderr.
124 /// createPrinterPass - Get a Pass appropriate to print the IR this
125 /// pass operates one (Module, Function or MachineFunction).
126 virtual Pass *createPrinterPass(raw_ostream &O,
127 const std::string &Banner) const = 0;
129 /// Each pass is responsible for assigning a pass manager to itself.
130 /// PMS is the stack of available pass manager.
131 virtual void assignPassManager(PMStack &,
132 PassManagerType = PMT_Unknown) {}
133 /// Check if available pass managers are suitable for this pass or not.
134 virtual void preparePassManager(PMStack &);
136 /// Return what kind of Pass Manager can manage this pass.
137 virtual PassManagerType getPotentialPassManagerType() const;
139 // Access AnalysisResolver
140 inline void setResolver(AnalysisResolver *AR) {
141 assert(!Resolver && "Resolver is already set");
144 inline AnalysisResolver *getResolver() {
148 /// getAnalysisUsage - This function should be overriden by passes that need
149 /// analysis information to do their job. If a pass specifies that it uses a
150 /// particular analysis result to this function, it can then use the
151 /// getAnalysis<AnalysisType>() function, below.
153 virtual void getAnalysisUsage(AnalysisUsage &) const;
155 /// releaseMemory() - This member can be implemented by a pass if it wants to
156 /// be able to release its memory when it is no longer needed. The default
157 /// behavior of passes is to hold onto memory for the entire duration of their
158 /// lifetime (which is the entire compile time). For pipelined passes, this
159 /// is not a big deal because that memory gets recycled every time the pass is
160 /// invoked on another program unit. For IP passes, it is more important to
161 /// free memory when it is unused.
163 /// Optionally implement this function to release pass memory when it is no
166 virtual void releaseMemory();
168 /// getAdjustedAnalysisPointer - This method is used when a pass implements
169 /// an analysis interface through multiple inheritance. If needed, it should
170 /// override this to adjust the this pointer as needed for the specified pass
172 virtual void *getAdjustedAnalysisPointer(const PassInfo *) {
175 virtual ImmutablePass *getAsImmutablePass() { return 0; }
176 virtual PMDataManager *getAsPMDataManager() { return 0; }
178 /// verifyAnalysis() - This member can be implemented by a analysis pass to
179 /// check state of analysis information.
180 virtual void verifyAnalysis() const;
182 // dumpPassStructure - Implement the -debug-passes=PassStructure option
183 virtual void dumpPassStructure(unsigned Offset = 0);
185 template<typename AnalysisClass>
186 static const PassInfo *getClassPassInfo() {
187 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
190 // lookupPassInfo - Return the pass info object for the specified pass class,
191 // or null if it is not known.
192 static const PassInfo *lookupPassInfo(intptr_t TI);
194 // lookupPassInfo - Return the pass info object for the pass with the given
195 // argument string, or null if it is not known.
196 static const PassInfo *lookupPassInfo(StringRef Arg);
198 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
199 /// get analysis information that might be around, for example to update it.
200 /// This is different than getAnalysis in that it can fail (if the analysis
201 /// results haven't been computed), so should only be used if you can handle
202 /// the case when the analysis is not available. This method is often used by
203 /// transformation APIs to update analysis results for a pass automatically as
204 /// the transform is performed.
206 template<typename AnalysisType> AnalysisType *
207 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
209 /// mustPreserveAnalysisID - This method serves the same function as
210 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
211 /// obviously cannot give you a properly typed instance of the class if you
212 /// don't have the class name available (use getAnalysisIfAvailable if you
213 /// do), but it can tell you if you need to preserve the pass at least.
215 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
217 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
218 /// to the analysis information that they claim to use by overriding the
219 /// getAnalysisUsage function.
221 template<typename AnalysisType>
222 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
224 template<typename AnalysisType>
225 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h
227 template<typename AnalysisType>
228 AnalysisType &getAnalysisID(const PassInfo *PI) const;
230 template<typename AnalysisType>
231 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
235 //===----------------------------------------------------------------------===//
236 /// ModulePass class - This class is used to implement unstructured
237 /// interprocedural optimizations and analyses. ModulePasses may do anything
238 /// they want to the program.
240 class ModulePass : public Pass {
242 /// createPrinterPass - Get a module printer pass.
243 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
245 /// runOnModule - Virtual method overriden by subclasses to process the module
246 /// being operated on.
247 virtual bool runOnModule(Module &M) = 0;
249 virtual void assignPassManager(PMStack &PMS,
250 PassManagerType T = PMT_ModulePassManager);
252 /// Return what kind of Pass Manager can manage this pass.
253 virtual PassManagerType getPotentialPassManagerType() const;
255 explicit ModulePass(intptr_t pid) : Pass(PT_Module, pid) {}
256 explicit ModulePass(const void *pid) : Pass(PT_Module, pid) {}
257 // Force out-of-line virtual method.
258 virtual ~ModulePass();
262 //===----------------------------------------------------------------------===//
263 /// ImmutablePass class - This class is used to provide information that does
264 /// not need to be run. This is useful for things like target information and
265 /// "basic" versions of AnalysisGroups.
267 class ImmutablePass : public ModulePass {
269 /// initializePass - This method may be overriden by immutable passes to allow
270 /// them to perform various initialization actions they require. This is
271 /// primarily because an ImmutablePass can "require" another ImmutablePass,
272 /// and if it does, the overloaded version of initializePass may get access to
273 /// these passes with getAnalysis<>.
275 virtual void initializePass();
277 virtual ImmutablePass *getAsImmutablePass() { return this; }
279 /// ImmutablePasses are never run.
281 bool runOnModule(Module &) { return false; }
283 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
284 explicit ImmutablePass(const void *pid)
287 // Force out-of-line virtual method.
288 virtual ~ImmutablePass();
291 //===----------------------------------------------------------------------===//
292 /// FunctionPass class - This class is used to implement most global
293 /// optimizations. Optimizations should subclass this class if they meet the
294 /// following constraints:
296 /// 1. Optimizations are organized globally, i.e., a function at a time
297 /// 2. Optimizing a function does not cause the addition or removal of any
298 /// functions in the module
300 class FunctionPass : public Pass {
302 explicit FunctionPass(intptr_t pid) : Pass(PT_Function, pid) {}
303 explicit FunctionPass(const void *pid) : Pass(PT_Function, pid) {}
305 /// createPrinterPass - Get a function printer pass.
306 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
308 /// doInitialization - Virtual method overridden by subclasses to do
309 /// any necessary per-module initialization.
311 virtual bool doInitialization(Module &);
313 /// runOnFunction - Virtual method overriden by subclasses to do the
314 /// per-function processing of the pass.
316 virtual bool runOnFunction(Function &F) = 0;
318 /// doFinalization - Virtual method overriden by subclasses to do any post
319 /// processing needed after all passes have run.
321 virtual bool doFinalization(Module &);
323 /// runOnModule - On a module, we run this pass by initializing,
324 /// ronOnFunction'ing once for every function in the module, then by
327 virtual bool runOnModule(Module &M);
329 /// run - On a function, we simply initialize, run the function, then
332 bool run(Function &F);
334 virtual void assignPassManager(PMStack &PMS,
335 PassManagerType T = PMT_FunctionPassManager);
337 /// Return what kind of Pass Manager can manage this pass.
338 virtual PassManagerType getPotentialPassManagerType() const;
343 //===----------------------------------------------------------------------===//
344 /// BasicBlockPass class - This class is used to implement most local
345 /// optimizations. Optimizations should subclass this class if they
346 /// meet the following constraints:
347 /// 1. Optimizations are local, operating on either a basic block or
348 /// instruction at a time.
349 /// 2. Optimizations do not modify the CFG of the contained function, or any
350 /// other basic block in the function.
351 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
353 class BasicBlockPass : public Pass {
355 explicit BasicBlockPass(intptr_t pid) : Pass(PT_BasicBlock, pid) {}
356 explicit BasicBlockPass(const void *pid) : Pass(PT_BasicBlock, pid) {}
358 /// createPrinterPass - Get a function printer pass.
359 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
361 /// doInitialization - Virtual method overridden by subclasses to do
362 /// any necessary per-module initialization.
364 virtual bool doInitialization(Module &);
366 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
367 /// to do any necessary per-function initialization.
369 virtual bool doInitialization(Function &);
371 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
372 /// per-basicblock processing of the pass.
374 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
376 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
377 /// do any post processing needed after all passes have run.
379 virtual bool doFinalization(Function &);
381 /// doFinalization - Virtual method overriden by subclasses to do any post
382 /// processing needed after all passes have run.
384 virtual bool doFinalization(Module &);
387 // To run this pass on a function, we simply call runOnBasicBlock once for
390 bool runOnFunction(Function &F);
392 virtual void assignPassManager(PMStack &PMS,
393 PassManagerType T = PMT_BasicBlockPassManager);
395 /// Return what kind of Pass Manager can manage this pass.
396 virtual PassManagerType getPotentialPassManagerType() const;
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"