1 //===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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"
50 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 typedef enum PassManagerType PassManagerType;
71 //===----------------------------------------------------------------------===//
72 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
73 /// interprocedural optimization or you do not fit into any of the more
74 /// constrained passes described below.
77 AnalysisResolver *Resolver; // Used to resolve analysis
80 // AnalysisImpls - This keeps track of which passes implement the interfaces
81 // that are required by the current pass (to implement getAnalysis()).
83 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
85 void operator=(const Pass&); // DO NOT IMPLEMENT
86 Pass(const Pass &); // DO NOT IMPLEMENT
88 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {}
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, and if nothing
94 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
95 /// intelligible name for the pass.
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 /// runPass - Run this pass, returning true if a modification was made to the
105 /// module argument. This should be implemented by all concrete subclasses.
107 virtual bool runPass(Module &M) { return false; }
108 virtual bool runPass(BasicBlock&) { return false; }
110 /// print - Print out the internal state of the pass. This is called by
111 /// Analyze to print out the contents of an analysis. Otherwise it is not
112 /// necessary to implement this method. Beware that the module pointer MAY be
113 /// null. This automatically forwards to a virtual function that does not
114 /// provide the Module* in case the analysis doesn't need it it can just be
117 virtual void print(std::ostream &O, const Module *M) const;
118 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
119 void dump() const; // dump - call print(std::cerr, 0);
121 /// Each pass is responsible for assigning a pass manager to itself.
122 /// PMS is the stack of available pass manager.
123 virtual void assignPassManager(PMStack &PMS,
124 PassManagerType T = PMT_Unknown) {}
125 /// Check if available pass managers are suitable for this pass or not.
126 virtual void preparePassManager(PMStack &PMS) {}
128 /// Return what kind of Pass Manager can manage this pass.
129 virtual PassManagerType getPotentialPassManagerType() const {
133 // Access AnalysisResolver
134 inline void setResolver(AnalysisResolver *AR) {
135 assert (!Resolver && "Resolver is already set");
138 inline AnalysisResolver *getResolver() {
139 assert (Resolver && "Resolver is not set");
143 /// getAnalysisUsage - This function should be overriden by passes that need
144 /// analysis information to do their job. If a pass specifies that it uses a
145 /// particular analysis result to this function, it can then use the
146 /// getAnalysis<AnalysisType>() function, below.
148 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
149 // By default, no analysis results are used, all are invalidated.
152 /// releaseMemory() - This member can be implemented by a pass if it wants to
153 /// be able to release its memory when it is no longer needed. The default
154 /// behavior of passes is to hold onto memory for the entire duration of their
155 /// lifetime (which is the entire compile time). For pipelined passes, this
156 /// is not a big deal because that memory gets recycled every time the pass is
157 /// invoked on another program unit. For IP passes, it is more important to
158 /// free memory when it is unused.
160 /// Optionally implement this function to release pass memory when it is no
163 virtual void releaseMemory() {}
165 /// verifyAnalysis() - This member can be implemented by a analysis pass to
166 /// check state of analysis information.
167 virtual void verifyAnalysis() const {}
169 // dumpPassStructure - Implement the -debug-passes=PassStructure option
170 virtual void dumpPassStructure(unsigned Offset = 0);
172 template<typename AnalysisClass>
173 static const PassInfo *getClassPassInfo() {
174 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
177 // lookupPassInfo - Return the pass info object for the specified pass class,
178 // or null if it is not known.
179 static const PassInfo *lookupPassInfo(intptr_t TI);
181 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
182 /// to get to the analysis information that might be around that needs to be
183 /// updated. This is different than getAnalysis in that it can fail (ie the
184 /// analysis results haven't been computed), so should only be used if you
185 /// provide the capability to update an analysis that exists. This method is
186 /// often used by transformation APIs to update analysis results for a pass
187 /// automatically as the transform is performed.
189 template<typename AnalysisType>
190 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
192 /// mustPreserveAnalysisID - This method serves the same function as
193 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
194 /// obviously cannot give you a properly typed instance of the class if you
195 /// don't have the class name available (use getAnalysisToUpdate if you do),
196 /// but it can tell you if you need to preserve the pass at least.
198 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
200 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
201 /// to the analysis information that they claim to use by overriding the
202 /// getAnalysisUsage function.
204 template<typename AnalysisType>
205 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
207 template<typename AnalysisType>
208 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
210 template<typename AnalysisType>
211 AnalysisType &getAnalysisID(const PassInfo *PI) const;
213 template<typename AnalysisType>
214 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
217 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
218 P.print(OS, 0); return OS;
221 //===----------------------------------------------------------------------===//
222 /// ModulePass class - This class is used to implement unstructured
223 /// interprocedural optimizations and analyses. ModulePasses may do anything
224 /// they want to the program.
226 class ModulePass : public Pass {
228 /// runOnModule - Virtual method overriden by subclasses to process the module
229 /// being operated on.
230 virtual bool runOnModule(Module &M) = 0;
232 virtual bool runPass(Module &M) { return runOnModule(M); }
233 virtual bool runPass(BasicBlock&) { return false; }
235 virtual void assignPassManager(PMStack &PMS,
236 PassManagerType T = PMT_ModulePassManager);
238 /// Return what kind of Pass Manager can manage this pass.
239 virtual PassManagerType getPotentialPassManagerType() const {
240 return PMT_ModulePassManager;
243 explicit ModulePass(intptr_t pid) : Pass(pid) {}
244 // Force out-of-line virtual method.
245 virtual ~ModulePass();
249 //===----------------------------------------------------------------------===//
250 /// ImmutablePass class - This class is used to provide information that does
251 /// not need to be run. This is useful for things like target information and
252 /// "basic" versions of AnalysisGroups.
254 class ImmutablePass : public ModulePass {
256 /// initializePass - This method may be overriden by immutable passes to allow
257 /// them to perform various initialization actions they require. This is
258 /// primarily because an ImmutablePass can "require" another ImmutablePass,
259 /// and if it does, the overloaded version of initializePass may get access to
260 /// these passes with getAnalysis<>.
262 virtual void initializePass() {}
264 /// ImmutablePasses are never run.
266 bool runOnModule(Module &M) { return false; }
268 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
269 // Force out-of-line virtual method.
270 virtual ~ImmutablePass();
273 //===----------------------------------------------------------------------===//
274 /// FunctionPass class - This class is used to implement most global
275 /// optimizations. Optimizations should subclass this class if they meet the
276 /// following constraints:
278 /// 1. Optimizations are organized globally, i.e., a function at a time
279 /// 2. Optimizing a function does not cause the addition or removal of any
280 /// functions in the module
282 class FunctionPass : public Pass {
284 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
286 /// doInitialization - Virtual method overridden by subclasses to do
287 /// any necessary per-module initialization.
289 virtual bool doInitialization(Module &M) { return false; }
291 /// runOnFunction - Virtual method overriden by subclasses to do the
292 /// per-function processing of the pass.
294 virtual bool runOnFunction(Function &F) = 0;
296 /// doFinalization - Virtual method overriden by subclasses to do any post
297 /// processing needed after all passes have run.
299 virtual bool doFinalization(Module &M) { return false; }
301 /// runOnModule - On a module, we run this pass by initializing,
302 /// ronOnFunction'ing once for every function in the module, then by
305 virtual bool runOnModule(Module &M);
307 /// run - On a function, we simply initialize, run the function, then
310 bool run(Function &F);
312 virtual void assignPassManager(PMStack &PMS,
313 PassManagerType T = PMT_FunctionPassManager);
315 /// Return what kind of Pass Manager can manage this pass.
316 virtual PassManagerType getPotentialPassManagerType() const {
317 return PMT_FunctionPassManager;
323 //===----------------------------------------------------------------------===//
324 /// BasicBlockPass class - This class is used to implement most local
325 /// optimizations. Optimizations should subclass this class if they
326 /// meet the following constraints:
327 /// 1. Optimizations are local, operating on either a basic block or
328 /// instruction at a time.
329 /// 2. Optimizations do not modify the CFG of the contained function, or any
330 /// other basic block in the function.
331 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
333 class BasicBlockPass : public Pass {
335 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
337 /// doInitialization - Virtual method overridden by subclasses to do
338 /// any necessary per-module initialization.
340 virtual bool doInitialization(Module &M) { return false; }
342 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
343 /// to do any necessary per-function initialization.
345 virtual bool doInitialization(Function &F) { return false; }
347 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
348 /// per-basicblock processing of the pass.
350 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
352 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
353 /// do any post processing needed after all passes have run.
355 virtual bool doFinalization(Function &F) { return false; }
357 /// doFinalization - Virtual method overriden by subclasses to do any post
358 /// processing needed after all passes have run.
360 virtual bool doFinalization(Module &M) { return false; }
363 // To run this pass on a function, we simply call runOnBasicBlock once for
366 bool runOnFunction(Function &F);
368 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
371 virtual bool runPass(Module &M) { return false; }
372 virtual bool runPass(BasicBlock &BB);
374 virtual void assignPassManager(PMStack &PMS,
375 PassManagerType T = PMT_BasicBlockPassManager);
377 /// Return what kind of Pass Manager can manage this pass.
378 virtual PassManagerType getPotentialPassManagerType() const {
379 return PMT_BasicBlockPassManager;
384 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
385 /// using PMStack. Each Pass implements assignPassManager() to connect itself
386 /// with appropriate manager. assignPassManager() walks PMStack to find
387 /// suitable manager.
389 /// PMStack is just a wrapper around standard deque that overrides pop() and
393 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
394 iterator begin() { return S.rbegin(); }
395 iterator end() { return S.rend(); }
397 void handleLastUserOverflow();
400 inline PMDataManager *top() { return S.back(); }
402 inline bool empty() { return S.empty(); }
406 std::deque<PMDataManager *> S;
410 /// If the user specifies the -time-passes argument on an LLVM tool command line
411 /// then the value of this boolean will be true, otherwise false.
412 /// @brief This is the storage for the -time-passes option.
413 extern bool TimePassesIsEnabled;
415 } // End llvm namespace
417 // Include support files that contain important APIs commonly used by Passes,
418 // but that we want to separate out to make it easier to read the header files.
420 #include "llvm/PassSupport.h"
421 #include "llvm/PassAnalysisSupport.h"