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/System/DataTypes.h"
46 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
76 void operator=(const Pass&); // DO NOT IMPLEMENT
77 Pass(const Pass &); // DO NOT IMPLEMENT
80 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {
81 assert(pid && "pid cannot be 0");
83 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) {
84 assert(pid && "pid cannot be 0");
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(raw_ostream &O, const Module *M) const;
107 void dump() const; // dump - Print to stderr.
109 /// Each pass is responsible for assigning a pass manager to itself.
110 /// PMS is the stack of available pass manager.
111 virtual void assignPassManager(PMStack &,
112 PassManagerType = PMT_Unknown) {}
113 /// Check if available pass managers are suitable for this pass or not.
114 virtual void preparePassManager(PMStack &);
116 /// Return what kind of Pass Manager can manage this pass.
117 virtual PassManagerType getPotentialPassManagerType() const;
119 // Access AnalysisResolver
120 inline void setResolver(AnalysisResolver *AR) {
121 assert (!Resolver && "Resolver is already set");
124 inline AnalysisResolver *getResolver() {
128 /// getAnalysisUsage - This function should be overriden by passes that need
129 /// analysis information to do their job. If a pass specifies that it uses a
130 /// particular analysis result to this function, it can then use the
131 /// getAnalysis<AnalysisType>() function, below.
133 virtual void getAnalysisUsage(AnalysisUsage &) const;
135 /// releaseMemory() - This member can be implemented by a pass if it wants to
136 /// be able to release its memory when it is no longer needed. The default
137 /// behavior of passes is to hold onto memory for the entire duration of their
138 /// lifetime (which is the entire compile time). For pipelined passes, this
139 /// is not a big deal because that memory gets recycled every time the pass is
140 /// invoked on another program unit. For IP passes, it is more important to
141 /// free memory when it is unused.
143 /// Optionally implement this function to release pass memory when it is no
146 virtual void releaseMemory();
148 /// getAdjustedAnalysisPointer - This method is used when a pass implements
149 /// an analysis interface through multiple inheritance. If needed, it should
150 /// override this to adjust the this pointer as needed for the specified pass
152 virtual void *getAdjustedAnalysisPointer(const PassInfo *PI) {
155 virtual ImmutablePass *getAsImmutablePass() { return 0; }
157 /// verifyAnalysis() - This member can be implemented by a analysis pass to
158 /// check state of analysis information.
159 virtual void verifyAnalysis() const;
161 // dumpPassStructure - Implement the -debug-passes=PassStructure option
162 virtual void dumpPassStructure(unsigned Offset = 0);
164 template<typename AnalysisClass>
165 static const PassInfo *getClassPassInfo() {
166 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
169 // lookupPassInfo - Return the pass info object for the specified pass class,
170 // or null if it is not known.
171 static const PassInfo *lookupPassInfo(intptr_t TI);
173 // lookupPassInfo - Return the pass info object for the pass with the given
174 // argument string, or null if it is not known.
175 static const PassInfo *lookupPassInfo(StringRef Arg);
177 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
178 /// get analysis information that might be around, for example to update it.
179 /// This is different than getAnalysis in that it can fail (if the analysis
180 /// results haven't been computed), so should only be used if you can handle
181 /// the case when the analysis is not available. This method is often used by
182 /// transformation APIs to update analysis results for a pass automatically as
183 /// the transform is performed.
185 template<typename AnalysisType> AnalysisType *
186 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
188 /// mustPreserveAnalysisID - This method serves the same function as
189 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
190 /// obviously cannot give you a properly typed instance of the class if you
191 /// don't have the class name available (use getAnalysisIfAvailable if you
192 /// do), but it can tell you if you need to preserve the pass at least.
194 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
196 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
197 /// to the analysis information that they claim to use by overriding the
198 /// getAnalysisUsage function.
200 template<typename AnalysisType>
201 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
203 template<typename AnalysisType>
204 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h
206 template<typename AnalysisType>
207 AnalysisType &getAnalysisID(const PassInfo *PI) const;
209 template<typename AnalysisType>
210 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
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;
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 virtual ImmutablePass *getAsImmutablePass() { return this; }
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 &);
286 /// runOnFunction - Virtual method overriden by subclasses to do the
287 /// per-function processing of the pass.
289 virtual bool runOnFunction(Function &F) = 0;
291 /// doFinalization - Virtual method overriden by subclasses to do any post
292 /// processing needed after all passes have run.
294 virtual bool doFinalization(Module &);
296 /// runOnModule - On a module, we run this pass by initializing,
297 /// ronOnFunction'ing once for every function in the module, then by
300 virtual bool runOnModule(Module &M);
302 /// run - On a function, we simply initialize, run the function, then
305 bool run(Function &F);
307 virtual void assignPassManager(PMStack &PMS,
308 PassManagerType T = PMT_FunctionPassManager);
310 /// Return what kind of Pass Manager can manage this pass.
311 virtual PassManagerType getPotentialPassManagerType() const;
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 &);
336 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
337 /// to do any necessary per-function initialization.
339 virtual bool doInitialization(Function &);
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 &);
351 /// doFinalization - Virtual method overriden by subclasses to do any post
352 /// processing needed after all passes have run.
354 virtual bool doFinalization(Module &);
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;
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"