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 bool isAnalysisPass; // True if this pass is an analysis pass.
77 // AnalysisImpls - This keeps track of which passes implement the interfaces
78 // that are required by the current pass (to implement getAnalysis()).
80 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
82 void operator=(const Pass&); // DO NOT IMPLEMENT
83 Pass(const Pass &); // DO NOT IMPLEMENT
85 explicit Pass(intptr_t pid, bool AP = false) : Resolver(0), PassID(pid),
87 explicit Pass(const void *pid, bool AP = false) : Resolver(0),
88 PassID((intptr_t)pid),
92 bool isAnalysis() const { return isAnalysisPass; }
93 /// getPassName - Return a nice clean name for a pass. This usually
94 /// implemented in terms of the name that is registered by one of the
95 /// Registration templates, but can be overloaded directly.
97 virtual const char *getPassName() const;
99 /// getPassInfo - Return the PassInfo data structure that corresponds to this
100 /// pass... If the pass has not been registered, this will return null.
102 const PassInfo *getPassInfo() const;
104 /// print - Print out the internal state of the pass. This is called by
105 /// Analyze to print out the contents of an analysis. Otherwise it is not
106 /// necessary to implement this method. Beware that the module pointer MAY be
107 /// null. This automatically forwards to a virtual function that does not
108 /// provide the Module* in case the analysis doesn't need it it can just be
111 virtual void print(std::ostream &O, const Module *M) const;
112 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
113 void dump() const; // dump - call print(std::cerr, 0);
115 /// Each pass is responsible for assigning a pass manager to itself.
116 /// PMS is the stack of available pass manager.
117 virtual void assignPassManager(PMStack &PMS,
118 PassManagerType T = PMT_Unknown) {}
119 /// Check if available pass managers are suitable for this pass or not.
120 virtual void preparePassManager(PMStack &PMS) {}
122 /// Return what kind of Pass Manager can manage this pass.
123 virtual PassManagerType getPotentialPassManagerType() const {
127 // Access AnalysisResolver
128 inline void setResolver(AnalysisResolver *AR) {
129 assert (!Resolver && "Resolver is already set");
132 inline AnalysisResolver *getResolver() {
133 assert (Resolver && "Resolver is not set");
137 /// getAnalysisUsage - This function should be overriden by passes that need
138 /// analysis information to do their job. If a pass specifies that it uses a
139 /// particular analysis result to this function, it can then use the
140 /// getAnalysis<AnalysisType>() function, below.
142 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
143 // By default, no analysis results are used, all are invalidated.
146 /// releaseMemory() - This member can be implemented by a pass if it wants to
147 /// be able to release its memory when it is no longer needed. The default
148 /// behavior of passes is to hold onto memory for the entire duration of their
149 /// lifetime (which is the entire compile time). For pipelined passes, this
150 /// is not a big deal because that memory gets recycled every time the pass is
151 /// invoked on another program unit. For IP passes, it is more important to
152 /// free memory when it is unused.
154 /// Optionally implement this function to release pass memory when it is no
157 virtual void releaseMemory() {}
159 /// verifyAnalysis() - This member can be implemented by a analysis pass to
160 /// check state of analysis information.
161 virtual void verifyAnalysis() const {}
163 // dumpPassStructure - Implement the -debug-passes=PassStructure option
164 virtual void dumpPassStructure(unsigned Offset = 0);
166 template<typename AnalysisClass>
167 static const PassInfo *getClassPassInfo() {
168 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
171 // lookupPassInfo - Return the pass info object for the specified pass class,
172 // or null if it is not known.
173 static const PassInfo *lookupPassInfo(intptr_t TI);
175 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
176 /// to get to the analysis information that might be around that needs to be
177 /// updated. This is different than getAnalysis in that it can fail (ie the
178 /// analysis results haven't been computed), so should only be used if you
179 /// provide the capability to update an analysis that exists. This method is
180 /// often used by transformation APIs to update analysis results for a pass
181 /// automatically as the transform is performed.
183 template<typename AnalysisType>
184 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
186 /// mustPreserveAnalysisID - This method serves the same function as
187 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
188 /// obviously cannot give you a properly typed instance of the class if you
189 /// don't have the class name available (use getAnalysisToUpdate if you do),
190 /// but it can tell you if you need to preserve the pass at least.
192 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
194 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
195 /// to the analysis information that they claim to use by overriding the
196 /// getAnalysisUsage function.
198 template<typename AnalysisType>
199 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
201 template<typename AnalysisType>
202 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
204 template<typename AnalysisType>
205 AnalysisType &getAnalysisID(const PassInfo *PI) const;
207 template<typename AnalysisType>
208 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
211 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
212 P.print(OS, 0); return OS;
215 //===----------------------------------------------------------------------===//
216 /// ModulePass class - This class is used to implement unstructured
217 /// interprocedural optimizations and analyses. ModulePasses may do anything
218 /// they want to the program.
220 class ModulePass : public Pass {
222 /// runOnModule - Virtual method overriden by subclasses to process the module
223 /// being operated on.
224 virtual bool runOnModule(Module &M) = 0;
226 virtual void assignPassManager(PMStack &PMS,
227 PassManagerType T = PMT_ModulePassManager);
229 /// Return what kind of Pass Manager can manage this pass.
230 virtual PassManagerType getPotentialPassManagerType() const {
231 return PMT_ModulePassManager;
234 explicit ModulePass(intptr_t pid, bool AP = false) : Pass(pid, AP) {}
235 explicit ModulePass(const void *pid, bool AP = false) : Pass(pid, AP) {}
236 // Force out-of-line virtual method.
237 virtual ~ModulePass();
241 //===----------------------------------------------------------------------===//
242 /// ImmutablePass class - This class is used to provide information that does
243 /// not need to be run. This is useful for things like target information and
244 /// "basic" versions of AnalysisGroups.
246 class ImmutablePass : public ModulePass {
248 /// initializePass - This method may be overriden by immutable passes to allow
249 /// them to perform various initialization actions they require. This is
250 /// primarily because an ImmutablePass can "require" another ImmutablePass,
251 /// and if it does, the overloaded version of initializePass may get access to
252 /// these passes with getAnalysis<>.
254 virtual void initializePass() {}
256 /// ImmutablePasses are never run.
258 bool runOnModule(Module &M) { return false; }
260 explicit ImmutablePass(intptr_t pid, bool AP = false) : ModulePass(pid, AP) {}
261 explicit ImmutablePass(const void *pid, bool AP = false)
262 : ModulePass(pid, AP) {}
264 // Force out-of-line virtual method.
265 virtual ~ImmutablePass();
268 //===----------------------------------------------------------------------===//
269 /// FunctionPass class - This class is used to implement most global
270 /// optimizations. Optimizations should subclass this class if they meet the
271 /// following constraints:
273 /// 1. Optimizations are organized globally, i.e., a function at a time
274 /// 2. Optimizing a function does not cause the addition or removal of any
275 /// functions in the module
277 class FunctionPass : public Pass {
279 explicit FunctionPass(intptr_t pid, bool AP = false) : Pass(pid, AP) {}
280 explicit FunctionPass(const void *pid, bool AP = false) : Pass(pid, AP) {}
282 /// doInitialization - Virtual method overridden by subclasses to do
283 /// any necessary per-module initialization.
285 virtual bool doInitialization(Module &M) { return false; }
287 /// runOnFunction - Virtual method overriden by subclasses to do the
288 /// per-function processing of the pass.
290 virtual bool runOnFunction(Function &F) = 0;
292 /// doFinalization - Virtual method overriden by subclasses to do any post
293 /// processing needed after all passes have run.
295 virtual bool doFinalization(Module &M) { return false; }
297 /// runOnModule - On a module, we run this pass by initializing,
298 /// ronOnFunction'ing once for every function in the module, then by
301 virtual bool runOnModule(Module &M);
303 /// run - On a function, we simply initialize, run the function, then
306 bool run(Function &F);
308 virtual void assignPassManager(PMStack &PMS,
309 PassManagerType T = PMT_FunctionPassManager);
311 /// Return what kind of Pass Manager can manage this pass.
312 virtual PassManagerType getPotentialPassManagerType() const {
313 return PMT_FunctionPassManager;
319 //===----------------------------------------------------------------------===//
320 /// BasicBlockPass class - This class is used to implement most local
321 /// optimizations. Optimizations should subclass this class if they
322 /// meet the following constraints:
323 /// 1. Optimizations are local, operating on either a basic block or
324 /// instruction at a time.
325 /// 2. Optimizations do not modify the CFG of the contained function, or any
326 /// other basic block in the function.
327 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
329 class BasicBlockPass : public Pass {
331 explicit BasicBlockPass(intptr_t pid, bool AP = false) : Pass(pid, AP) {}
332 explicit BasicBlockPass(const void *pid, bool AP = false) : Pass(pid, AP) {}
334 /// doInitialization - Virtual method overridden by subclasses to do
335 /// any necessary per-module initialization.
337 virtual bool doInitialization(Module &M) { return false; }
339 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
340 /// to do any necessary per-function initialization.
342 virtual bool doInitialization(Function &F) { return false; }
344 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
345 /// per-basicblock processing of the pass.
347 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
349 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
350 /// do any post processing needed after all passes have run.
352 virtual bool doFinalization(Function &F) { return false; }
354 /// doFinalization - Virtual method overriden by subclasses to do any post
355 /// processing needed after all passes have run.
357 virtual bool doFinalization(Module &M) { return false; }
360 // To run this pass on a function, we simply call runOnBasicBlock once for
363 bool runOnFunction(Function &F);
365 virtual void assignPassManager(PMStack &PMS,
366 PassManagerType T = PMT_BasicBlockPassManager);
368 /// Return what kind of Pass Manager can manage this pass.
369 virtual PassManagerType getPotentialPassManagerType() const {
370 return PMT_BasicBlockPassManager;
374 /// If the user specifies the -time-passes argument on an LLVM tool command line
375 /// then the value of this boolean will be true, otherwise false.
376 /// @brief This is the storage for the -time-passes option.
377 extern bool TimePassesIsEnabled;
379 } // End llvm namespace
381 // Include support files that contain important APIs commonly used by Passes,
382 // but that we want to separate out to make it easier to read the header files.
384 #include "llvm/PassSupport.h"
385 #include "llvm/PassAnalysisSupport.h"