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/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 typedef enum PassManagerType PassManagerType;
70 //===----------------------------------------------------------------------===//
71 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
72 /// interprocedural optimization or you do not fit into any of the more
73 /// constrained passes described below.
76 AnalysisResolver *Resolver; // Used to resolve analysis
79 // AnalysisImpls - This keeps track of which passes implement the interfaces
80 // that are required by the current pass (to implement getAnalysis()).
82 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
84 void operator=(const Pass&); // DO NOT IMPLEMENT
85 Pass(const Pass &); // DO NOT IMPLEMENT
87 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {}
90 /// getPassName - Return a nice clean name for a pass. This usually
91 /// implemented in terms of the name that is registered by one of the
92 /// Registration templates, but can be overloaded directly, and if nothing
93 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
94 /// intelligible name for the pass.
96 virtual const char *getPassName() const;
98 /// getPassInfo - Return the PassInfo data structure that corresponds to this
99 /// pass... If the pass has not been registered, this will return null.
101 const PassInfo *getPassInfo() const;
103 /// runPass - Run this pass, returning true if a modification was made to the
104 /// module argument. This should be implemented by all concrete subclasses.
106 virtual bool runPass(Module &M) { return false; }
107 virtual bool runPass(BasicBlock&) { return false; }
109 /// print - Print out the internal state of the pass. This is called by
110 /// Analyze to print out the contents of an analysis. Otherwise it is not
111 /// necessary to implement this method. Beware that the module pointer MAY be
112 /// null. This automatically forwards to a virtual function that does not
113 /// provide the Module* in case the analysis doesn't need it it can just be
116 virtual void print(std::ostream &O, const Module *M) const;
117 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
118 void dump() const; // dump - call print(std::cerr, 0);
120 /// Each pass is responsible for assigning a pass manager to itself.
121 /// PMS is the stack of available pass manager.
122 virtual void assignPassManager(PMStack &PMS,
123 PassManagerType T = PMT_Unknown) {}
124 /// Check if available pass managers are suitable for this pass or not.
125 virtual void preparePassManager(PMStack &PMS) {}
127 /// Return what kind of Pass Manager can manage this pass.
128 virtual PassManagerType getPotentialPassManagerType() const {
132 // Access AnalysisResolver
133 inline void setResolver(AnalysisResolver *AR) {
134 assert (!Resolver && "Resolver is already set");
137 inline AnalysisResolver *getResolver() {
138 assert (Resolver && "Resolver is not set");
142 /// getAnalysisUsage - This function should be overriden by passes that need
143 /// analysis information to do their job. If a pass specifies that it uses a
144 /// particular analysis result to this function, it can then use the
145 /// getAnalysis<AnalysisType>() function, below.
147 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
148 // By default, no analysis results are used, all are invalidated.
151 /// releaseMemory() - This member can be implemented by a pass if it wants to
152 /// be able to release its memory when it is no longer needed. The default
153 /// behavior of passes is to hold onto memory for the entire duration of their
154 /// lifetime (which is the entire compile time). For pipelined passes, this
155 /// is not a big deal because that memory gets recycled every time the pass is
156 /// invoked on another program unit. For IP passes, it is more important to
157 /// free memory when it is unused.
159 /// Optionally implement this function to release pass memory when it is no
162 virtual void releaseMemory() {}
164 // dumpPassStructure - Implement the -debug-passes=PassStructure option
165 virtual void dumpPassStructure(unsigned Offset = 0);
167 template<typename AnalysisClass>
168 static const PassInfo *getClassPassInfo() {
169 return lookupPassInfo((intptr_t)&AnalysisClass::ID);
172 // lookupPassInfo - Return the pass info object for the specified pass class,
173 // or null if it is not known.
174 static const PassInfo *lookupPassInfo(intptr_t TI);
176 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
177 /// to get to the analysis information that might be around that needs to be
178 /// updated. This is different than getAnalysis in that it can fail (ie the
179 /// analysis results haven't been computed), so should only be used if you
180 /// provide the capability to update an analysis that exists. This method is
181 /// often used by transformation APIs to update analysis results for a pass
182 /// automatically as the transform is performed.
184 template<typename AnalysisType>
185 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
187 /// mustPreserveAnalysisID - This method serves the same function as
188 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
189 /// obviously cannot give you a properly typed instance of the class if you
190 /// don't have the class name available (use getAnalysisToUpdate if you do),
191 /// but it can tell you if you need to preserve the pass at least.
193 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
195 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
196 /// to the analysis information that they claim to use by overriding the
197 /// getAnalysisUsage function.
199 template<typename AnalysisType>
200 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
202 template<typename AnalysisType>
203 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
205 template<typename AnalysisType>
206 AnalysisType &getAnalysisID(const PassInfo *PI) const;
208 template<typename AnalysisType>
209 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
212 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
213 P.print(OS, 0); return OS;
216 //===----------------------------------------------------------------------===//
217 /// ModulePass class - This class is used to implement unstructured
218 /// interprocedural optimizations and analyses. ModulePasses may do anything
219 /// they want to the program.
221 class ModulePass : public Pass {
223 /// runOnModule - Virtual method overriden by subclasses to process the module
224 /// being operated on.
225 virtual bool runOnModule(Module &M) = 0;
227 virtual bool runPass(Module &M) { return runOnModule(M); }
228 virtual bool runPass(BasicBlock&) { return false; }
230 virtual void assignPassManager(PMStack &PMS,
231 PassManagerType T = PMT_ModulePassManager);
233 /// Return what kind of Pass Manager can manage this pass.
234 virtual PassManagerType getPotentialPassManagerType() const {
235 return PMT_ModulePassManager;
238 explicit ModulePass(intptr_t pid) : Pass(pid) {}
239 // Force out-of-line virtual method.
240 virtual ~ModulePass();
244 //===----------------------------------------------------------------------===//
245 /// ImmutablePass class - This class is used to provide information that does
246 /// not need to be run. This is useful for things like target information and
247 /// "basic" versions of AnalysisGroups.
249 class ImmutablePass : public ModulePass {
251 /// initializePass - This method may be overriden by immutable passes to allow
252 /// them to perform various initialization actions they require. This is
253 /// primarily because an ImmutablePass can "require" another ImmutablePass,
254 /// and if it does, the overloaded version of initializePass may get access to
255 /// these passes with getAnalysis<>.
257 virtual void initializePass() {}
259 /// ImmutablePasses are never run.
261 virtual bool runOnModule(Module &M) { return false; }
263 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
264 // Force out-of-line virtual method.
265 virtual ~ImmutablePass();
268 //===----------------------------------------------------------------------===//
269 /// FunctionPass class - This class is used to implement most global
270 /// optimizations. Optimizations should subclass this class if they meet the
271 /// following constraints:
273 /// 1. Optimizations are organized globally, i.e., a function at a time
274 /// 2. Optimizing a function does not cause the addition or removal of any
275 /// functions in the module
277 class FunctionPass : public Pass {
279 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
281 /// doInitialization - Virtual method overridden by subclasses to do
282 /// any necessary per-module initialization.
284 virtual bool doInitialization(Module &M) { return false; }
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 &M) { return false; }
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 {
312 return PMT_FunctionPassManager;
318 //===----------------------------------------------------------------------===//
319 /// BasicBlockPass class - This class is used to implement most local
320 /// optimizations. Optimizations should subclass this class if they
321 /// meet the following constraints:
322 /// 1. Optimizations are local, operating on either a basic block or
323 /// instruction at a time.
324 /// 2. Optimizations do not modify the CFG of the contained function, or any
325 /// other basic block in the function.
326 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
328 class BasicBlockPass : public Pass {
330 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
332 /// doInitialization - Virtual method overridden by subclasses to do
333 /// any necessary per-module initialization.
335 virtual bool doInitialization(Module &M) { return false; }
337 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
338 /// to do any necessary per-function initialization.
340 virtual bool doInitialization(Function &F) { return false; }
342 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
343 /// per-basicblock processing of the pass.
345 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
347 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
348 /// do any post processing needed after all passes have run.
350 virtual bool doFinalization(Function &F) { return false; }
352 /// doFinalization - Virtual method overriden by subclasses to do any post
353 /// processing needed after all passes have run.
355 virtual bool doFinalization(Module &M) { return false; }
358 // To run this pass on a function, we simply call runOnBasicBlock once for
361 bool runOnFunction(Function &F);
363 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
366 virtual bool runPass(Module &M) { return false; }
367 virtual bool runPass(BasicBlock &BB);
369 virtual void assignPassManager(PMStack &PMS,
370 PassManagerType T = PMT_BasicBlockPassManager);
372 /// Return what kind of Pass Manager can manage this pass.
373 virtual PassManagerType getPotentialPassManagerType() const {
374 return PMT_BasicBlockPassManager;
379 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
380 /// using PMStack. Each Pass implements assignPassManager() to connect itself
381 /// with appropriate manager. assignPassManager() walks PMStack to find
382 /// suitable manager.
384 /// PMStack is just a wrapper around standard deque that overrides pop() and
388 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
389 iterator begin() { return S.rbegin(); }
390 iterator end() { return S.rend(); }
392 void handleLastUserOverflow();
395 inline PMDataManager *top() { return S.back(); }
397 inline bool empty() { return S.empty(); }
401 std::deque<PMDataManager *> S;
405 /// If the user specifies the -time-passes argument on an LLVM tool command line
406 /// then the value of this boolean will be true, otherwise false.
407 /// @brief This is the storage for the -time-passes option.
408 extern bool TimePassesIsEnabled;
410 } // End llvm namespace
412 // Include support files that contain important APIs commonly used by Passes,
413 // but that we want to separate out to make it easier to read the header files.
415 #include "llvm/PassSupport.h"
416 #include "llvm/PassAnalysisSupport.h"