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"
48 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 //===----------------------------------------------------------------------===//
68 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
69 /// interprocedural optimization or you do not fit into any of the more
70 /// constrained passes described below.
73 AnalysisResolver *Resolver; // Used to resolve analysis
75 // AnalysisImpls - This keeps track of which passes implement the interfaces
76 // that are required by the current pass (to implement getAnalysis()).
78 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
80 void operator=(const Pass&); // DO NOT IMPLEMENT
81 Pass(const Pass &); // DO NOT IMPLEMENT
83 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {
84 assert(pid && "pid cannot be 0");
86 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) {
87 assert(pid && "pid cannot be 0");
91 /// getPassName - Return a nice clean name for a pass. This usually
92 /// implemented in terms of the name that is registered by one of the
93 /// Registration templates, but can be overloaded directly.
95 virtual const char *getPassName() const;
97 /// getPassInfo - Return the PassInfo data structure that corresponds to this
98 /// pass... If the pass has not been registered, this will return null.
100 const PassInfo *getPassInfo() const;
102 /// print - Print out the internal state of the pass. This is called by
103 /// Analyze to print out the contents of an analysis. Otherwise it is not
104 /// necessary to implement this method. Beware that the module pointer MAY be
105 /// null. This automatically forwards to a virtual function that does not
106 /// provide the Module* in case the analysis doesn't need it it can just be
109 virtual void print(std::ostream &O, const Module *M) const;
110 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
111 void dump() const; // dump - call print(std::cerr, 0);
113 /// Each pass is responsible for assigning a pass manager to itself.
114 /// PMS is the stack of available pass manager.
115 virtual void assignPassManager(PMStack &,
116 PassManagerType = PMT_Unknown) {}
117 /// Check if available pass managers are suitable for this pass or not.
118 virtual void preparePassManager(PMStack &) {}
120 /// Return what kind of Pass Manager can manage this pass.
121 virtual PassManagerType getPotentialPassManagerType() const {
125 // Access AnalysisResolver
126 inline void setResolver(AnalysisResolver *AR) {
127 assert (!Resolver && "Resolver is already set");
130 inline AnalysisResolver *getResolver() {
134 /// getAnalysisUsage - This function should be overriden by passes that need
135 /// analysis information to do their job. If a pass specifies that it uses a
136 /// particular analysis result to this function, it can then use the
137 /// getAnalysis<AnalysisType>() function, below.
139 virtual void getAnalysisUsage(AnalysisUsage &) const {
140 // By default, no analysis results are used, all are invalidated.
143 /// releaseMemory() - This member can be implemented by a pass if it wants to
144 /// be able to release its memory when it is no longer needed. The default
145 /// behavior of passes is to hold onto memory for the entire duration of their
146 /// lifetime (which is the entire compile time). For pipelined passes, this
147 /// is not a big deal because that memory gets recycled every time the pass is
148 /// invoked on another program unit. For IP passes, it is more important to
149 /// free memory when it is unused.
151 /// Optionally implement this function to release pass memory when it is no
154 virtual void releaseMemory() {}
156 /// verifyAnalysis() - This member can be implemented by a analysis pass to
157 /// check state of analysis information.
158 virtual void verifyAnalysis() const {}
160 // dumpPassStructure - Implement the -debug-passes=PassStructure option
161 virtual void dumpPassStructure(unsigned Offset = 0);
163 template<typename AnalysisClass>
164 static const PassInfo *getClassPassInfo() {
165 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
168 // lookupPassInfo - Return the pass info object for the specified pass class,
169 // or null if it is not known.
170 static const PassInfo *lookupPassInfo(intptr_t TI);
172 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
173 /// to get to the analysis information that might be around that needs to be
174 /// updated. This is different than getAnalysis in that it can fail (ie the
175 /// analysis results haven't been computed), so should only be used if you
176 /// provide the capability to update an analysis that exists. This method is
177 /// often used by transformation APIs to update analysis results for a pass
178 /// automatically as the transform is performed.
180 template<typename AnalysisType>
181 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
183 /// mustPreserveAnalysisID - This method serves the same function as
184 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
185 /// obviously cannot give you a properly typed instance of the class if you
186 /// don't have the class name available (use getAnalysisToUpdate if you do),
187 /// but it can tell you if you need to preserve the pass at least.
189 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
191 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
192 /// to the analysis information that they claim to use by overriding the
193 /// getAnalysisUsage function.
195 template<typename AnalysisType>
196 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
198 template<typename AnalysisType>
199 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
201 template<typename AnalysisType>
202 AnalysisType &getAnalysisID(const PassInfo *PI) const;
204 template<typename AnalysisType>
205 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
208 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
209 P.print(OS, 0); return OS;
212 //===----------------------------------------------------------------------===//
213 /// ModulePass class - This class is used to implement unstructured
214 /// interprocedural optimizations and analyses. ModulePasses may do anything
215 /// they want to the program.
217 class ModulePass : public Pass {
219 /// runOnModule - Virtual method overriden by subclasses to process the module
220 /// being operated on.
221 virtual bool runOnModule(Module &M) = 0;
223 virtual void assignPassManager(PMStack &PMS,
224 PassManagerType T = PMT_ModulePassManager);
226 /// Return what kind of Pass Manager can manage this pass.
227 virtual PassManagerType getPotentialPassManagerType() const {
228 return PMT_ModulePassManager;
231 explicit ModulePass(intptr_t pid) : Pass(pid) {}
232 explicit ModulePass(const void *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 bool runOnModule(Module &) { return false; }
257 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
258 explicit ImmutablePass(const void *pid)
261 // Force out-of-line virtual method.
262 virtual ~ImmutablePass();
265 //===----------------------------------------------------------------------===//
266 /// FunctionPass class - This class is used to implement most global
267 /// optimizations. Optimizations should subclass this class if they meet the
268 /// following constraints:
270 /// 1. Optimizations are organized globally, i.e., a function at a time
271 /// 2. Optimizing a function does not cause the addition or removal of any
272 /// functions in the module
274 class FunctionPass : public Pass {
276 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
277 explicit FunctionPass(const void *pid) : Pass(pid) {}
279 /// doInitialization - Virtual method overridden by subclasses to do
280 /// any necessary per-module initialization.
282 virtual bool doInitialization(Module &) { return false; }
284 /// runOnFunction - Virtual method overriden by subclasses to do the
285 /// per-function processing of the pass.
287 virtual bool runOnFunction(Function &F) = 0;
289 /// doFinalization - Virtual method overriden by subclasses to do any post
290 /// processing needed after all passes have run.
292 virtual bool doFinalization(Module &) { return false; }
294 /// runOnModule - On a module, we run this pass by initializing,
295 /// ronOnFunction'ing once for every function in the module, then by
298 virtual bool runOnModule(Module &M);
300 /// run - On a function, we simply initialize, run the function, then
303 bool run(Function &F);
305 virtual void assignPassManager(PMStack &PMS,
306 PassManagerType T = PMT_FunctionPassManager);
308 /// Return what kind of Pass Manager can manage this pass.
309 virtual PassManagerType getPotentialPassManagerType() const {
310 return PMT_FunctionPassManager;
316 //===----------------------------------------------------------------------===//
317 /// BasicBlockPass class - This class is used to implement most local
318 /// optimizations. Optimizations should subclass this class if they
319 /// meet the following constraints:
320 /// 1. Optimizations are local, operating on either a basic block or
321 /// instruction at a time.
322 /// 2. Optimizations do not modify the CFG of the contained function, or any
323 /// other basic block in the function.
324 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
326 class BasicBlockPass : public Pass {
328 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
329 explicit BasicBlockPass(const void *pid) : Pass(pid) {}
331 /// doInitialization - Virtual method overridden by subclasses to do
332 /// any necessary per-module initialization.
334 virtual bool doInitialization(Module &) { return false; }
336 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
337 /// to do any necessary per-function initialization.
339 virtual bool doInitialization(Function &) { return false; }
341 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
342 /// per-basicblock processing of the pass.
344 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
346 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
347 /// do any post processing needed after all passes have run.
349 virtual bool doFinalization(Function &) { return false; }
351 /// doFinalization - Virtual method overriden by subclasses to do any post
352 /// processing needed after all passes have run.
354 virtual bool doFinalization(Module &) { return false; }
357 // To run this pass on a function, we simply call runOnBasicBlock once for
360 bool runOnFunction(Function &F);
362 virtual void assignPassManager(PMStack &PMS,
363 PassManagerType T = PMT_BasicBlockPassManager);
365 /// Return what kind of Pass Manager can manage this pass.
366 virtual PassManagerType getPotentialPassManagerType() const {
367 return PMT_BasicBlockPassManager;
371 /// If the user specifies the -time-passes argument on an LLVM tool command line
372 /// then the value of this boolean will be true, otherwise false.
373 /// @brief This is the storage for the -time-passes option.
374 extern bool TimePassesIsEnabled;
376 } // End llvm namespace
378 // Include support files that contain important APIs commonly used by Passes,
379 // but that we want to separate out to make it easier to read the header files.
381 #include "llvm/PassSupport.h"
382 #include "llvm/PassAnalysisSupport.h"