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/Module.h"
33 #include "llvm/Support/DataTypes.h"
34 #include "llvm/Support/Streams.h"
49 class AnalysisResolver;
53 // AnalysisID - Use the PassInfo to identify a pass...
54 typedef const PassInfo* AnalysisID;
56 /// Different types of internal pass managers. External pass managers
57 /// (PassManager and FunctionPassManager) are not represented here.
58 /// Ordering of pass manager types is important here.
59 enum PassManagerType {
61 PMT_ModulePassManager = 1, /// MPPassManager
62 PMT_CallGraphPassManager, /// CGPassManager
63 PMT_FunctionPassManager, /// FPPassManager
64 PMT_LoopPassManager, /// LPPassManager
65 PMT_BasicBlockPassManager, /// BBPassManager
69 //===----------------------------------------------------------------------===//
70 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
71 /// interprocedural optimization or you do not fit into any of the more
72 /// constrained passes described below.
75 AnalysisResolver *Resolver; // Used to resolve analysis
78 void operator=(const Pass&); // DO NOT IMPLEMENT
79 Pass(const Pass &); // DO NOT IMPLEMENT
85 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {
86 assert(pid && "pid cannot be 0");
88 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) {
89 assert(pid && "pid cannot be 0");
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 &,
118 PassManagerType = PMT_Unknown) {}
119 /// Check if available pass managers are suitable for this pass or not.
120 virtual void preparePassManager(PMStack &) {}
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() {
136 /// getAnalysisUsage - This function should be overriden by passes that need
137 /// analysis information to do their job. If a pass specifies that it uses a
138 /// particular analysis result to this function, it can then use the
139 /// getAnalysis<AnalysisType>() function, below.
141 virtual void getAnalysisUsage(AnalysisUsage &) const {
142 // By default, no analysis results are used, all are invalidated.
145 /// releaseMemory() - This member can be implemented by a pass if it wants to
146 /// be able to release its memory when it is no longer needed. The default
147 /// behavior of passes is to hold onto memory for the entire duration of their
148 /// lifetime (which is the entire compile time). For pipelined passes, this
149 /// is not a big deal because that memory gets recycled every time the pass is
150 /// invoked on another program unit. For IP passes, it is more important to
151 /// free memory when it is unused.
153 /// Optionally implement this function to release pass memory when it is no
156 virtual void releaseMemory() {}
158 /// verifyAnalysis() - This member can be implemented by a analysis pass to
159 /// check state of analysis information.
160 virtual void verifyAnalysis() const {}
162 // dumpPassStructure - Implement the -debug-passes=PassStructure option
163 virtual void dumpPassStructure(unsigned Offset = 0);
165 template<typename AnalysisClass>
166 static const PassInfo *getClassPassInfo() {
167 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
170 // lookupPassInfo - Return the pass info object for the specified pass class,
171 // or null if it is not known.
172 static const PassInfo *lookupPassInfo(intptr_t TI);
174 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
175 /// get analysis information that might be around, for example to update it.
176 /// This is different than getAnalysis in that it can fail (if the analysis
177 /// results haven't been computed), so should only be used if you can handle
178 /// the case when the analysis is not available. This method is often used by
179 /// transformation APIs to update analysis results for a pass automatically as
180 /// the transform is performed.
182 template<typename AnalysisType> AnalysisType *
183 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
185 /// mustPreserveAnalysisID - This method serves the same function as
186 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
187 /// obviously cannot give you a properly typed instance of the class if you
188 /// don't have the class name available (use getAnalysisIfAvailable if you
189 /// do), but it can tell you if you need to preserve the pass at least.
191 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
193 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
194 /// to the analysis information that they claim to use by overriding the
195 /// getAnalysisUsage function.
197 template<typename AnalysisType>
198 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
200 template<typename AnalysisType>
201 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
203 template<typename AnalysisType>
204 AnalysisType &getAnalysisID(const PassInfo *PI) const;
206 template<typename AnalysisType>
207 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
210 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
211 P.print(OS, 0); return OS;
214 //===----------------------------------------------------------------------===//
215 /// ModulePass class - This class is used to implement unstructured
216 /// interprocedural optimizations and analyses. ModulePasses may do anything
217 /// they want to the program.
219 class ModulePass : public Pass {
221 /// runOnModule - Virtual method overriden by subclasses to process the module
222 /// being operated on.
223 virtual bool runOnModule(Module &M) = 0;
225 virtual void assignPassManager(PMStack &PMS,
226 PassManagerType T = PMT_ModulePassManager);
228 /// Return what kind of Pass Manager can manage this pass.
229 virtual PassManagerType getPotentialPassManagerType() const {
230 return PMT_ModulePassManager;
233 explicit ModulePass(intptr_t pid) : Pass(pid) {}
234 explicit ModulePass(const void *pid) : Pass(pid) {}
235 // Force out-of-line virtual method.
236 virtual ~ModulePass();
240 //===----------------------------------------------------------------------===//
241 /// ImmutablePass class - This class is used to provide information that does
242 /// not need to be run. This is useful for things like target information and
243 /// "basic" versions of AnalysisGroups.
245 class ImmutablePass : public ModulePass {
247 /// initializePass - This method may be overriden by immutable passes to allow
248 /// them to perform various initialization actions they require. This is
249 /// primarily because an ImmutablePass can "require" another ImmutablePass,
250 /// and if it does, the overloaded version of initializePass may get access to
251 /// these passes with getAnalysis<>.
253 virtual void initializePass() {}
255 /// ImmutablePasses are never run.
257 bool runOnModule(Module &) { return false; }
259 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
260 explicit ImmutablePass(const void *pid)
263 // Force out-of-line virtual method.
264 virtual ~ImmutablePass();
267 //===----------------------------------------------------------------------===//
268 /// FunctionPass class - This class is used to implement most global
269 /// optimizations. Optimizations should subclass this class if they meet the
270 /// following constraints:
272 /// 1. Optimizations are organized globally, i.e., a function at a time
273 /// 2. Optimizing a function does not cause the addition or removal of any
274 /// functions in the module
276 class FunctionPass : public Pass {
278 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
279 explicit FunctionPass(const void *pid) : Pass(pid) {}
281 /// doInitialization - Virtual method overridden by subclasses to do
282 /// any necessary per-module initialization.
284 virtual bool doInitialization(Module &M) {
285 Context = &M.getContext();
289 /// runOnFunction - Virtual method overriden by subclasses to do the
290 /// per-function processing of the pass.
292 virtual bool runOnFunction(Function &F) = 0;
294 /// doFinalization - Virtual method overriden by subclasses to do any post
295 /// processing needed after all passes have run.
297 virtual bool doFinalization(Module &) { return false; }
299 /// runOnModule - On a module, we run this pass by initializing,
300 /// ronOnFunction'ing once for every function in the module, then by
303 virtual bool runOnModule(Module &M);
305 /// run - On a function, we simply initialize, run the function, then
308 bool run(Function &F);
310 virtual void assignPassManager(PMStack &PMS,
311 PassManagerType T = PMT_FunctionPassManager);
313 /// Return what kind of Pass Manager can manage this pass.
314 virtual PassManagerType getPotentialPassManagerType() const {
315 return PMT_FunctionPassManager;
321 //===----------------------------------------------------------------------===//
322 /// BasicBlockPass class - This class is used to implement most local
323 /// optimizations. Optimizations should subclass this class if they
324 /// meet the following constraints:
325 /// 1. Optimizations are local, operating on either a basic block or
326 /// instruction at a time.
327 /// 2. Optimizations do not modify the CFG of the contained function, or any
328 /// other basic block in the function.
329 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
331 class BasicBlockPass : public Pass {
333 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
334 explicit BasicBlockPass(const void *pid) : Pass(pid) {}
336 /// doInitialization - Virtual method overridden by subclasses to do
337 /// any necessary per-module initialization.
339 virtual bool doInitialization(Module &M) {
340 Context = &M.getContext();
344 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
345 /// to do any necessary per-function initialization.
347 virtual bool doInitialization(Function &) { return false; }
349 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
350 /// per-basicblock processing of the pass.
352 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
354 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
355 /// do any post processing needed after all passes have run.
357 virtual bool doFinalization(Function &) { return false; }
359 /// doFinalization - Virtual method overriden by subclasses to do any post
360 /// processing needed after all passes have run.
362 virtual bool doFinalization(Module &) { return false; }
365 // To run this pass on a function, we simply call runOnBasicBlock once for
368 bool runOnFunction(Function &F);
370 virtual void assignPassManager(PMStack &PMS,
371 PassManagerType T = PMT_BasicBlockPassManager);
373 /// Return what kind of Pass Manager can manage this pass.
374 virtual PassManagerType getPotentialPassManagerType() const {
375 return PMT_BasicBlockPassManager;
379 /// If the user specifies the -time-passes argument on an LLVM tool command line
380 /// then the value of this boolean will be true, otherwise false.
381 /// @brief This is the storage for the -time-passes option.
382 extern bool TimePassesIsEnabled;
384 } // End llvm namespace
386 // Include support files that contain important APIs commonly used by Passes,
387 // but that we want to separate out to make it easier to read the header files.
389 #include "llvm/PassSupport.h"
390 #include "llvm/PassAnalysisSupport.h"