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"
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) {}
89 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) {}
92 /// getPassName - Return a nice clean name for a pass. This usually
93 /// implemented in terms of the name that is registered by one of the
94 /// Registration templates, but can be overloaded directly, and if nothing
95 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
96 /// intelligible name for the pass.
98 virtual const char *getPassName() const;
100 /// getPassInfo - Return the PassInfo data structure that corresponds to this
101 /// pass... If the pass has not been registered, this will return null.
103 const PassInfo *getPassInfo() const;
105 /// runPass - Run this pass, returning true if a modification was made to the
106 /// module argument. This should be implemented by all concrete subclasses.
108 virtual bool runPass(Module &M) { return false; }
109 virtual bool runPass(BasicBlock&) { return false; }
111 /// print - Print out the internal state of the pass. This is called by
112 /// Analyze to print out the contents of an analysis. Otherwise it is not
113 /// necessary to implement this method. Beware that the module pointer MAY be
114 /// null. This automatically forwards to a virtual function that does not
115 /// provide the Module* in case the analysis doesn't need it it can just be
118 virtual void print(std::ostream &O, const Module *M) const;
119 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
120 void dump() const; // dump - call print(std::cerr, 0);
122 /// Each pass is responsible for assigning a pass manager to itself.
123 /// PMS is the stack of available pass manager.
124 virtual void assignPassManager(PMStack &PMS,
125 PassManagerType T = PMT_Unknown) {}
126 /// Check if available pass managers are suitable for this pass or not.
127 virtual void preparePassManager(PMStack &PMS) {}
129 /// Return what kind of Pass Manager can manage this pass.
130 virtual PassManagerType getPotentialPassManagerType() const {
134 // Access AnalysisResolver
135 inline void setResolver(AnalysisResolver *AR) {
136 assert (!Resolver && "Resolver is already set");
139 inline AnalysisResolver *getResolver() {
140 assert (Resolver && "Resolver is not set");
144 /// getAnalysisUsage - This function should be overriden by passes that need
145 /// analysis information to do their job. If a pass specifies that it uses a
146 /// particular analysis result to this function, it can then use the
147 /// getAnalysis<AnalysisType>() function, below.
149 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
150 // By default, no analysis results are used, all are invalidated.
153 /// releaseMemory() - This member can be implemented by a pass if it wants to
154 /// be able to release its memory when it is no longer needed. The default
155 /// behavior of passes is to hold onto memory for the entire duration of their
156 /// lifetime (which is the entire compile time). For pipelined passes, this
157 /// is not a big deal because that memory gets recycled every time the pass is
158 /// invoked on another program unit. For IP passes, it is more important to
159 /// free memory when it is unused.
161 /// Optionally implement this function to release pass memory when it is no
164 virtual void releaseMemory() {}
166 /// verifyAnalysis() - This member can be implemented by a analysis pass to
167 /// check state of analysis information.
168 virtual void verifyAnalysis() const {}
170 // dumpPassStructure - Implement the -debug-passes=PassStructure option
171 virtual void dumpPassStructure(unsigned Offset = 0);
173 template<typename AnalysisClass>
174 static const PassInfo *getClassPassInfo() {
175 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
178 // lookupPassInfo - Return the pass info object for the specified pass class,
179 // or null if it is not known.
180 static const PassInfo *lookupPassInfo(intptr_t TI);
182 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
183 /// to get to the analysis information that might be around that needs to be
184 /// updated. This is different than getAnalysis in that it can fail (ie the
185 /// analysis results haven't been computed), so should only be used if you
186 /// provide the capability to update an analysis that exists. This method is
187 /// often used by transformation APIs to update analysis results for a pass
188 /// automatically as the transform is performed.
190 template<typename AnalysisType>
191 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
193 /// mustPreserveAnalysisID - This method serves the same function as
194 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
195 /// obviously cannot give you a properly typed instance of the class if you
196 /// don't have the class name available (use getAnalysisToUpdate if you do),
197 /// but it can tell you if you need to preserve the pass at least.
199 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
201 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
202 /// to the analysis information that they claim to use by overriding the
203 /// getAnalysisUsage function.
205 template<typename AnalysisType>
206 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
208 template<typename AnalysisType>
209 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
211 template<typename AnalysisType>
212 AnalysisType &getAnalysisID(const PassInfo *PI) const;
214 template<typename AnalysisType>
215 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
218 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
219 P.print(OS, 0); return OS;
222 //===----------------------------------------------------------------------===//
223 /// ModulePass class - This class is used to implement unstructured
224 /// interprocedural optimizations and analyses. ModulePasses may do anything
225 /// they want to the program.
227 class ModulePass : public Pass {
229 /// runOnModule - Virtual method overriden by subclasses to process the module
230 /// being operated on.
231 virtual bool runOnModule(Module &M) = 0;
233 virtual bool runPass(Module &M) { return runOnModule(M); }
234 virtual bool runPass(BasicBlock&) { return false; }
236 virtual void assignPassManager(PMStack &PMS,
237 PassManagerType T = PMT_ModulePassManager);
239 /// Return what kind of Pass Manager can manage this pass.
240 virtual PassManagerType getPotentialPassManagerType() const {
241 return PMT_ModulePassManager;
244 explicit ModulePass(intptr_t pid) : Pass(pid) {}
245 explicit ModulePass(const void *pid) : Pass(pid) {}
246 // Force out-of-line virtual method.
247 virtual ~ModulePass();
251 //===----------------------------------------------------------------------===//
252 /// ImmutablePass class - This class is used to provide information that does
253 /// not need to be run. This is useful for things like target information and
254 /// "basic" versions of AnalysisGroups.
256 class ImmutablePass : public ModulePass {
258 /// initializePass - This method may be overriden by immutable passes to allow
259 /// them to perform various initialization actions they require. This is
260 /// primarily because an ImmutablePass can "require" another ImmutablePass,
261 /// and if it does, the overloaded version of initializePass may get access to
262 /// these passes with getAnalysis<>.
264 virtual void initializePass() {}
266 /// ImmutablePasses are never run.
268 bool runOnModule(Module &M) { return false; }
270 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
271 explicit ImmutablePass(const void *pid) : ModulePass(pid) {}
273 // Force out-of-line virtual method.
274 virtual ~ImmutablePass();
277 //===----------------------------------------------------------------------===//
278 /// FunctionPass class - This class is used to implement most global
279 /// optimizations. Optimizations should subclass this class if they meet the
280 /// following constraints:
282 /// 1. Optimizations are organized globally, i.e., a function at a time
283 /// 2. Optimizing a function does not cause the addition or removal of any
284 /// functions in the module
286 class FunctionPass : public Pass {
288 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
289 explicit FunctionPass(const void *pid) : Pass(pid) {}
291 /// doInitialization - Virtual method overridden by subclasses to do
292 /// any necessary per-module initialization.
294 virtual bool doInitialization(Module &M) { return false; }
296 /// runOnFunction - Virtual method overriden by subclasses to do the
297 /// per-function processing of the pass.
299 virtual bool runOnFunction(Function &F) = 0;
301 /// doFinalization - Virtual method overriden by subclasses to do any post
302 /// processing needed after all passes have run.
304 virtual bool doFinalization(Module &M) { return false; }
306 /// runOnModule - On a module, we run this pass by initializing,
307 /// ronOnFunction'ing once for every function in the module, then by
310 virtual bool runOnModule(Module &M);
312 /// run - On a function, we simply initialize, run the function, then
315 bool run(Function &F);
317 virtual void assignPassManager(PMStack &PMS,
318 PassManagerType T = PMT_FunctionPassManager);
320 /// Return what kind of Pass Manager can manage this pass.
321 virtual PassManagerType getPotentialPassManagerType() const {
322 return PMT_FunctionPassManager;
328 //===----------------------------------------------------------------------===//
329 /// BasicBlockPass class - This class is used to implement most local
330 /// optimizations. Optimizations should subclass this class if they
331 /// meet the following constraints:
332 /// 1. Optimizations are local, operating on either a basic block or
333 /// instruction at a time.
334 /// 2. Optimizations do not modify the CFG of the contained function, or any
335 /// other basic block in the function.
336 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
338 class BasicBlockPass : public Pass {
340 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
341 explicit BasicBlockPass(const void *pid) : Pass(pid) {}
343 /// doInitialization - Virtual method overridden by subclasses to do
344 /// any necessary per-module initialization.
346 virtual bool doInitialization(Module &M) { return false; }
348 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
349 /// to do any necessary per-function initialization.
351 virtual bool doInitialization(Function &F) { return false; }
353 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
354 /// per-basicblock processing of the pass.
356 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
358 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
359 /// do any post processing needed after all passes have run.
361 virtual bool doFinalization(Function &F) { return false; }
363 /// doFinalization - Virtual method overriden by subclasses to do any post
364 /// processing needed after all passes have run.
366 virtual bool doFinalization(Module &M) { return false; }
369 // To run this pass on a function, we simply call runOnBasicBlock once for
372 bool runOnFunction(Function &F);
374 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
377 virtual bool runPass(Module &M) { return false; }
378 virtual bool runPass(BasicBlock &BB);
380 virtual void assignPassManager(PMStack &PMS,
381 PassManagerType T = PMT_BasicBlockPassManager);
383 /// Return what kind of Pass Manager can manage this pass.
384 virtual PassManagerType getPotentialPassManagerType() const {
385 return PMT_BasicBlockPassManager;
390 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
391 /// using PMStack. Each Pass implements assignPassManager() to connect itself
392 /// with appropriate manager. assignPassManager() walks PMStack to find
393 /// suitable manager.
395 /// PMStack is just a wrapper around standard deque that overrides pop() and
399 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
400 iterator begin() { return S.rbegin(); }
401 iterator end() { return S.rend(); }
403 void handleLastUserOverflow();
406 inline PMDataManager *top() { return S.back(); }
408 inline bool empty() { return S.empty(); }
412 std::deque<PMDataManager *> S;
416 /// If the user specifies the -time-passes argument on an LLVM tool command line
417 /// then the value of this boolean will be true, otherwise false.
418 /// @brief This is the storage for the -time-passes option.
419 extern bool TimePassesIsEnabled;
421 } // End llvm namespace
423 // Include support files that contain important APIs commonly used by Passes,
424 // but that we want to separate out to make it easier to read the header files.
426 #include "llvm/PassSupport.h"
427 #include "llvm/PassAnalysisSupport.h"