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() {
128 assert (Resolver && "Resolver is not set");
132 /// getAnalysisUsage - This function should be overriden by passes that need
133 /// analysis information to do their job. If a pass specifies that it uses a
134 /// particular analysis result to this function, it can then use the
135 /// getAnalysis<AnalysisType>() function, below.
137 virtual void getAnalysisUsage(AnalysisUsage &) const {
138 // By default, no analysis results are used, all are invalidated.
141 /// releaseMemory() - This member can be implemented by a pass if it wants to
142 /// be able to release its memory when it is no longer needed. The default
143 /// behavior of passes is to hold onto memory for the entire duration of their
144 /// lifetime (which is the entire compile time). For pipelined passes, this
145 /// is not a big deal because that memory gets recycled every time the pass is
146 /// invoked on another program unit. For IP passes, it is more important to
147 /// free memory when it is unused.
149 /// Optionally implement this function to release pass memory when it is no
152 virtual void releaseMemory() {}
154 /// verifyAnalysis() - This member can be implemented by a analysis pass to
155 /// check state of analysis information.
156 virtual void verifyAnalysis() const {}
158 // dumpPassStructure - Implement the -debug-passes=PassStructure option
159 virtual void dumpPassStructure(unsigned Offset = 0);
161 template<typename AnalysisClass>
162 static const PassInfo *getClassPassInfo() {
163 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
166 // lookupPassInfo - Return the pass info object for the specified pass class,
167 // or null if it is not known.
168 static const PassInfo *lookupPassInfo(intptr_t TI);
170 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
171 /// to get to the analysis information that might be around that needs to be
172 /// updated. This is different than getAnalysis in that it can fail (ie the
173 /// analysis results haven't been computed), so should only be used if you
174 /// provide the capability to update an analysis that exists. This method is
175 /// often used by transformation APIs to update analysis results for a pass
176 /// automatically as the transform is performed.
178 template<typename AnalysisType>
179 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
181 /// mustPreserveAnalysisID - This method serves the same function as
182 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
183 /// obviously cannot give you a properly typed instance of the class if you
184 /// don't have the class name available (use getAnalysisToUpdate if you do),
185 /// but it can tell you if you need to preserve the pass at least.
187 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
189 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
190 /// to the analysis information that they claim to use by overriding the
191 /// getAnalysisUsage function.
193 template<typename AnalysisType>
194 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
196 template<typename AnalysisType>
197 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
199 template<typename AnalysisType>
200 AnalysisType &getAnalysisID(const PassInfo *PI) const;
202 template<typename AnalysisType>
203 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
206 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
207 P.print(OS, 0); return OS;
210 //===----------------------------------------------------------------------===//
211 /// ModulePass class - This class is used to implement unstructured
212 /// interprocedural optimizations and analyses. ModulePasses may do anything
213 /// they want to the program.
215 class ModulePass : public Pass {
217 /// runOnModule - Virtual method overriden by subclasses to process the module
218 /// being operated on.
219 virtual bool runOnModule(Module &M) = 0;
221 virtual void assignPassManager(PMStack &PMS,
222 PassManagerType T = PMT_ModulePassManager);
224 /// Return what kind of Pass Manager can manage this pass.
225 virtual PassManagerType getPotentialPassManagerType() const {
226 return PMT_ModulePassManager;
229 explicit ModulePass(intptr_t pid) : Pass(pid) {}
230 explicit ModulePass(const void *pid) : Pass(pid) {}
231 // Force out-of-line virtual method.
232 virtual ~ModulePass();
236 //===----------------------------------------------------------------------===//
237 /// ImmutablePass class - This class is used to provide information that does
238 /// not need to be run. This is useful for things like target information and
239 /// "basic" versions of AnalysisGroups.
241 class ImmutablePass : public ModulePass {
243 /// initializePass - This method may be overriden by immutable passes to allow
244 /// them to perform various initialization actions they require. This is
245 /// primarily because an ImmutablePass can "require" another ImmutablePass,
246 /// and if it does, the overloaded version of initializePass may get access to
247 /// these passes with getAnalysis<>.
249 virtual void initializePass() {}
251 /// ImmutablePasses are never run.
253 bool runOnModule(Module &) { return false; }
255 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
256 explicit ImmutablePass(const void *pid)
259 // Force out-of-line virtual method.
260 virtual ~ImmutablePass();
263 //===----------------------------------------------------------------------===//
264 /// FunctionPass class - This class is used to implement most global
265 /// optimizations. Optimizations should subclass this class if they meet the
266 /// following constraints:
268 /// 1. Optimizations are organized globally, i.e., a function at a time
269 /// 2. Optimizing a function does not cause the addition or removal of any
270 /// functions in the module
272 class FunctionPass : public Pass {
274 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
275 explicit FunctionPass(const void *pid) : Pass(pid) {}
277 /// doInitialization - Virtual method overridden by subclasses to do
278 /// any necessary per-module initialization.
280 virtual bool doInitialization(Module &) { return false; }
282 /// runOnFunction - Virtual method overriden by subclasses to do the
283 /// per-function processing of the pass.
285 virtual bool runOnFunction(Function &F) = 0;
287 /// doFinalization - Virtual method overriden by subclasses to do any post
288 /// processing needed after all passes have run.
290 virtual bool doFinalization(Module &) { return false; }
292 /// runOnModule - On a module, we run this pass by initializing,
293 /// ronOnFunction'ing once for every function in the module, then by
296 virtual bool runOnModule(Module &M);
298 /// run - On a function, we simply initialize, run the function, then
301 bool run(Function &F);
303 virtual void assignPassManager(PMStack &PMS,
304 PassManagerType T = PMT_FunctionPassManager);
306 /// Return what kind of Pass Manager can manage this pass.
307 virtual PassManagerType getPotentialPassManagerType() const {
308 return PMT_FunctionPassManager;
314 //===----------------------------------------------------------------------===//
315 /// BasicBlockPass class - This class is used to implement most local
316 /// optimizations. Optimizations should subclass this class if they
317 /// meet the following constraints:
318 /// 1. Optimizations are local, operating on either a basic block or
319 /// instruction at a time.
320 /// 2. Optimizations do not modify the CFG of the contained function, or any
321 /// other basic block in the function.
322 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
324 class BasicBlockPass : public Pass {
326 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
327 explicit BasicBlockPass(const void *pid) : Pass(pid) {}
329 /// doInitialization - Virtual method overridden by subclasses to do
330 /// any necessary per-module initialization.
332 virtual bool doInitialization(Module &) { return false; }
334 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
335 /// to do any necessary per-function initialization.
337 virtual bool doInitialization(Function &) { return false; }
339 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
340 /// per-basicblock processing of the pass.
342 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
344 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
345 /// do any post processing needed after all passes have run.
347 virtual bool doFinalization(Function &) { return false; }
349 /// doFinalization - Virtual method overriden by subclasses to do any post
350 /// processing needed after all passes have run.
352 virtual bool doFinalization(Module &) { return false; }
355 // To run this pass on a function, we simply call runOnBasicBlock once for
358 bool runOnFunction(Function &F);
360 virtual void assignPassManager(PMStack &PMS,
361 PassManagerType T = PMT_BasicBlockPassManager);
363 /// Return what kind of Pass Manager can manage this pass.
364 virtual PassManagerType getPotentialPassManagerType() const {
365 return PMT_BasicBlockPassManager;
369 /// If the user specifies the -time-passes argument on an LLVM tool command line
370 /// then the value of this boolean will be true, otherwise false.
371 /// @brief This is the storage for the -time-passes option.
372 extern bool TimePassesIsEnabled;
374 } // End llvm namespace
376 // Include support files that contain important APIs commonly used by Passes,
377 // but that we want to separate out to make it easier to read the header files.
379 #include "llvm/PassSupport.h"
380 #include "llvm/PassAnalysisSupport.h"