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/Support/DataTypes.h"
33 #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 //===----------------------------------------------------------------------===//
69 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
70 /// interprocedural optimization or you do not fit into any of the more
71 /// constrained passes described below.
74 AnalysisResolver *Resolver; // Used to resolve analysis
76 // AnalysisImpls - This keeps track of which passes implement the interfaces
77 // that are required by the current pass (to implement getAnalysis()).
79 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
81 void operator=(const Pass&); // DO NOT IMPLEMENT
82 Pass(const Pass &); // DO NOT IMPLEMENT
84 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {}
85 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) {}
88 /// getPassName - Return a nice clean name for a pass. This usually
89 /// implemented in terms of the name that is registered by one of the
90 /// Registration templates, but can be overloaded directly.
92 virtual const char *getPassName() const;
94 /// getPassInfo - Return the PassInfo data structure that corresponds to this
95 /// pass... If the pass has not been registered, this will return null.
97 const PassInfo *getPassInfo() const;
99 /// print - Print out the internal state of the pass. This is called by
100 /// Analyze to print out the contents of an analysis. Otherwise it is not
101 /// necessary to implement this method. Beware that the module pointer MAY be
102 /// null. This automatically forwards to a virtual function that does not
103 /// provide the Module* in case the analysis doesn't need it it can just be
106 virtual void print(std::ostream &O, const Module *M) const;
107 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
108 void dump() const; // dump - call print(std::cerr, 0);
110 /// Each pass is responsible for assigning a pass manager to itself.
111 /// PMS is the stack of available pass manager.
112 virtual void assignPassManager(PMStack &,
113 PassManagerType = PMT_Unknown) {}
114 /// Check if available pass managers are suitable for this pass or not.
115 virtual void preparePassManager(PMStack &) {}
117 /// Return what kind of Pass Manager can manage this pass.
118 virtual PassManagerType getPotentialPassManagerType() const {
122 // Access AnalysisResolver
123 inline void setResolver(AnalysisResolver *AR) {
124 assert (!Resolver && "Resolver is already set");
127 inline AnalysisResolver *getResolver() {
131 /// getAnalysisUsage - This function should be overriden by passes that need
132 /// analysis information to do their job. If a pass specifies that it uses a
133 /// particular analysis result to this function, it can then use the
134 /// getAnalysis<AnalysisType>() function, below.
136 virtual void getAnalysisUsage(AnalysisUsage &) const {
137 // By default, no analysis results are used, all are invalidated.
140 /// releaseMemory() - This member can be implemented by a pass if it wants to
141 /// be able to release its memory when it is no longer needed. The default
142 /// behavior of passes is to hold onto memory for the entire duration of their
143 /// lifetime (which is the entire compile time). For pipelined passes, this
144 /// is not a big deal because that memory gets recycled every time the pass is
145 /// invoked on another program unit. For IP passes, it is more important to
146 /// free memory when it is unused.
148 /// Optionally implement this function to release pass memory when it is no
151 virtual void releaseMemory() {}
153 /// verifyAnalysis() - This member can be implemented by a analysis pass to
154 /// check state of analysis information.
155 virtual void verifyAnalysis() const {}
157 // dumpPassStructure - Implement the -debug-passes=PassStructure option
158 virtual void dumpPassStructure(unsigned Offset = 0);
160 template<typename AnalysisClass>
161 static const PassInfo *getClassPassInfo() {
162 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
165 // lookupPassInfo - Return the pass info object for the specified pass class,
166 // or null if it is not known.
167 static const PassInfo *lookupPassInfo(intptr_t TI);
169 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
170 /// to get to the analysis information that might be around that needs to be
171 /// updated. This is different than getAnalysis in that it can fail (ie the
172 /// analysis results haven't been computed), so should only be used if you
173 /// provide the capability to update an analysis that exists. This method is
174 /// often used by transformation APIs to update analysis results for a pass
175 /// automatically as the transform is performed.
177 template<typename AnalysisType>
178 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
180 /// mustPreserveAnalysisID - This method serves the same function as
181 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
182 /// obviously cannot give you a properly typed instance of the class if you
183 /// don't have the class name available (use getAnalysisToUpdate if you do),
184 /// but it can tell you if you need to preserve the pass at least.
186 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
188 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
189 /// to the analysis information that they claim to use by overriding the
190 /// getAnalysisUsage function.
192 template<typename AnalysisType>
193 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
195 template<typename AnalysisType>
196 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
198 template<typename AnalysisType>
199 AnalysisType &getAnalysisID(const PassInfo *PI) const;
201 template<typename AnalysisType>
202 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
205 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
206 P.print(OS, 0); return OS;
209 //===----------------------------------------------------------------------===//
210 /// ModulePass class - This class is used to implement unstructured
211 /// interprocedural optimizations and analyses. ModulePasses may do anything
212 /// they want to the program.
214 class ModulePass : public Pass {
216 /// runOnModule - Virtual method overriden by subclasses to process the module
217 /// being operated on.
218 virtual bool runOnModule(Module &M) = 0;
220 virtual void assignPassManager(PMStack &PMS,
221 PassManagerType T = PMT_ModulePassManager);
223 /// Return what kind of Pass Manager can manage this pass.
224 virtual PassManagerType getPotentialPassManagerType() const {
225 return PMT_ModulePassManager;
228 explicit ModulePass(intptr_t pid) : Pass(pid) {}
229 explicit ModulePass(const void *pid) : Pass(pid) {}
230 // Force out-of-line virtual method.
231 virtual ~ModulePass();
235 //===----------------------------------------------------------------------===//
236 /// ImmutablePass class - This class is used to provide information that does
237 /// not need to be run. This is useful for things like target information and
238 /// "basic" versions of AnalysisGroups.
240 class ImmutablePass : public ModulePass {
242 /// initializePass - This method may be overriden by immutable passes to allow
243 /// them to perform various initialization actions they require. This is
244 /// primarily because an ImmutablePass can "require" another ImmutablePass,
245 /// and if it does, the overloaded version of initializePass may get access to
246 /// these passes with getAnalysis<>.
248 virtual void initializePass() {}
250 /// ImmutablePasses are never run.
252 bool runOnModule(Module &) { return false; }
254 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
255 explicit ImmutablePass(const void *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) {}
274 explicit FunctionPass(const void *pid) : Pass(pid) {}
276 /// doInitialization - Virtual method overridden by subclasses to do
277 /// any necessary per-module initialization.
279 virtual bool doInitialization(Module &) { return false; }
281 /// runOnFunction - Virtual method overriden by subclasses to do the
282 /// per-function processing of the pass.
284 virtual bool runOnFunction(Function &F) = 0;
286 /// doFinalization - Virtual method overriden by subclasses to do any post
287 /// processing needed after all passes have run.
289 virtual bool doFinalization(Module &) { return false; }
291 /// runOnModule - On a module, we run this pass by initializing,
292 /// ronOnFunction'ing once for every function in the module, then by
295 virtual bool runOnModule(Module &M);
297 /// run - On a function, we simply initialize, run the function, then
300 bool run(Function &F);
302 virtual void assignPassManager(PMStack &PMS,
303 PassManagerType T = PMT_FunctionPassManager);
305 /// Return what kind of Pass Manager can manage this pass.
306 virtual PassManagerType getPotentialPassManagerType() const {
307 return PMT_FunctionPassManager;
313 //===----------------------------------------------------------------------===//
314 /// BasicBlockPass class - This class is used to implement most local
315 /// optimizations. Optimizations should subclass this class if they
316 /// meet the following constraints:
317 /// 1. Optimizations are local, operating on either a basic block or
318 /// instruction at a time.
319 /// 2. Optimizations do not modify the CFG of the contained function, or any
320 /// other basic block in the function.
321 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
323 class BasicBlockPass : public Pass {
325 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
326 explicit BasicBlockPass(const void *pid) : Pass(pid) {}
328 /// doInitialization - Virtual method overridden by subclasses to do
329 /// any necessary per-module initialization.
331 virtual bool doInitialization(Module &) { return false; }
333 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
334 /// to do any necessary per-function initialization.
336 virtual bool doInitialization(Function &) { return false; }
338 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
339 /// per-basicblock processing of the pass.
341 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
343 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
344 /// do any post processing needed after all passes have run.
346 virtual bool doFinalization(Function &) { return false; }
348 /// doFinalization - Virtual method overriden by subclasses to do any post
349 /// processing needed after all passes have run.
351 virtual bool doFinalization(Module &) { return false; }
354 // To run this pass on a function, we simply call runOnBasicBlock once for
357 bool runOnFunction(Function &F);
359 virtual void assignPassManager(PMStack &PMS,
360 PassManagerType T = PMT_BasicBlockPassManager);
362 /// Return what kind of Pass Manager can manage this pass.
363 virtual PassManagerType getPotentialPassManagerType() const {
364 return PMT_BasicBlockPassManager;
368 /// If the user specifies the -time-passes argument on an LLVM tool command line
369 /// then the value of this boolean will be true, otherwise false.
370 /// @brief This is the storage for the -time-passes option.
371 extern bool TimePassesIsEnabled;
373 } // End llvm namespace
375 // Include support files that contain important APIs commonly used by Passes,
376 // but that we want to separate out to make it easier to read the header files.
378 #include "llvm/PassSupport.h"
379 #include "llvm/PassAnalysisSupport.h"