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"
48 class BasicBlockPassManager;
49 class ModulePassManager;
51 class AnalysisResolver;
54 // AnalysisID - Use the PassInfo to identify a pass...
55 typedef const PassInfo* AnalysisID;
57 /// Different types of internal pass managers. External pass managers
58 /// (PassManager and FunctionPassManager) are not represented here.
59 /// Ordering of pass manager types is important here.
60 enum PassManagerType {
62 PMT_ModulePassManager = 1, /// MPPassManager
63 PMT_CallGraphPassManager, /// CGPassManager
64 PMT_FunctionPassManager, /// FPPassManager
65 PMT_LoopPassManager, /// LPPassManager
66 PMT_BasicBlockPassManager, /// BBPassManager
70 typedef enum PassManagerType PassManagerType;
72 //===----------------------------------------------------------------------===//
73 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
74 /// interprocedural optimization or you do not fit into any of the more
75 /// constrained passes described below.
78 AnalysisResolver *Resolver; // Used to resolve analysis
81 // AnalysisImpls - This keeps track of which passes implement the interfaces
82 // that are required by the current pass (to implement getAnalysis()).
84 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
86 void operator=(const Pass&); // DO NOT IMPLEMENT
87 Pass(const Pass &); // DO NOT IMPLEMENT
89 Pass(intptr_t pid) : Resolver(0), PassID(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) { Resolver = AR; }
136 inline AnalysisResolver *getResolver() { return Resolver; }
138 /// getAnalysisUsage - This function should be overriden by passes that need
139 /// analysis information to do their job. If a pass specifies that it uses a
140 /// particular analysis result to this function, it can then use the
141 /// getAnalysis<AnalysisType>() function, below.
143 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
144 // By default, no analysis results are used, all are invalidated.
147 /// releaseMemory() - This member can be implemented by a pass if it wants to
148 /// be able to release its memory when it is no longer needed. The default
149 /// behavior of passes is to hold onto memory for the entire duration of their
150 /// lifetime (which is the entire compile time). For pipelined passes, this
151 /// is not a big deal because that memory gets recycled every time the pass is
152 /// invoked on another program unit. For IP passes, it is more important to
153 /// free memory when it is unused.
155 /// Optionally implement this function to release pass memory when it is no
158 virtual void releaseMemory() {}
160 // dumpPassStructure - Implement the -debug-passes=PassStructure option
161 virtual void dumpPassStructure(unsigned Offset = 0);
163 template<typename AnalysisClass>
164 static const PassInfo *getClassPassInfo() {
165 return lookupPassInfo((intptr_t)&AnalysisClass::ID);
168 // lookupPassInfo - Return the pass info object for the specified pass class,
169 // or null if it is not known.
170 static const PassInfo *lookupPassInfo(intptr_t TI);
172 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
173 /// to get to the analysis information that might be around that needs to be
174 /// updated. This is different than getAnalysis in that it can fail (ie the
175 /// analysis results haven't been computed), so should only be used if you
176 /// provide the capability to update an analysis that exists. This method is
177 /// often used by transformation APIs to update analysis results for a pass
178 /// automatically as the transform is performed.
180 template<typename AnalysisType>
181 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
183 /// mustPreserveAnalysisID - This method serves the same function as
184 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
185 /// obviously cannot give you a properly typed instance of the class if you
186 /// don't have the class name available (use getAnalysisToUpdate if you do),
187 /// but it can tell you if you need to preserve the pass at least.
189 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
191 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
192 /// to the analysis information that they claim to use by overriding the
193 /// getAnalysisUsage function.
195 template<typename AnalysisType>
196 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
198 template<typename AnalysisType>
199 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
201 template<typename AnalysisType>
202 AnalysisType &getAnalysisID(const PassInfo *PI) const;
204 template<typename AnalysisType>
205 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
208 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
209 P.print(OS, 0); return OS;
212 //===----------------------------------------------------------------------===//
213 /// ModulePass class - This class is used to implement unstructured
214 /// interprocedural optimizations and analyses. ModulePasses may do anything
215 /// they want to the program.
217 class ModulePass : public Pass {
219 /// runOnModule - Virtual method overriden by subclasses to process the module
220 /// being operated on.
221 virtual bool runOnModule(Module &M) = 0;
223 virtual bool runPass(Module &M) { return runOnModule(M); }
224 virtual bool runPass(BasicBlock&) { return false; }
226 virtual void assignPassManager(PMStack &PMS,
227 PassManagerType T = PMT_ModulePassManager);
229 /// Return what kind of Pass Manager can manage this pass.
230 virtual PassManagerType getPotentialPassManagerType() const {
231 return PMT_ModulePassManager;
234 ModulePass(intptr_t 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 virtual bool runOnModule(Module &M) { return false; }
259 ImmutablePass(intptr_t pid) : ModulePass(pid) {}
260 // Force out-of-line virtual method.
261 virtual ~ImmutablePass();
264 //===----------------------------------------------------------------------===//
265 /// FunctionPass class - This class is used to implement most global
266 /// optimizations. Optimizations should subclass this class if they meet the
267 /// following constraints:
269 /// 1. Optimizations are organized globally, i.e., a function at a time
270 /// 2. Optimizing a function does not cause the addition or removal of any
271 /// functions in the module
273 class FunctionPass : public Pass {
275 FunctionPass(intptr_t pid) : Pass(pid) {}
277 /// doInitialization - Virtual method overridden by subclasses to do
278 /// any necessary per-module initialization.
280 virtual bool doInitialization(Module &M) { return false; }
282 /// runOnFunction - Virtual method overriden by subclasses to do the
283 /// per-function processing of the pass.
285 virtual bool runOnFunction(Function &F) = 0;
287 /// doFinalization - Virtual method overriden by subclasses to do any post
288 /// processing needed after all passes have run.
290 virtual bool doFinalization(Module &M) { return false; }
292 /// runOnModule - On a module, we run this pass by initializing,
293 /// ronOnFunction'ing once for every function in the module, then by
296 virtual bool runOnModule(Module &M);
298 /// run - On a function, we simply initialize, run the function, then
301 bool run(Function &F);
303 virtual void assignPassManager(PMStack &PMS,
304 PassManagerType T = PMT_FunctionPassManager);
306 /// Return what kind of Pass Manager can manage this pass.
307 virtual PassManagerType getPotentialPassManagerType() const {
308 return PMT_FunctionPassManager;
314 //===----------------------------------------------------------------------===//
315 /// BasicBlockPass class - This class is used to implement most local
316 /// optimizations. Optimizations should subclass this class if they
317 /// meet the following constraints:
318 /// 1. Optimizations are local, operating on either a basic block or
319 /// instruction at a time.
320 /// 2. Optimizations do not modify the CFG of the contained function, or any
321 /// other basic block in the function.
322 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
324 class BasicBlockPass : public Pass {
326 BasicBlockPass(intptr_t pid) : Pass(pid) {}
328 /// doInitialization - Virtual method overridden by subclasses to do
329 /// any necessary per-module initialization.
331 virtual bool doInitialization(Module &M) { return false; }
333 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
334 /// to do any necessary per-function initialization.
336 virtual bool doInitialization(Function &F) { return false; }
338 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
339 /// per-basicblock processing of the pass.
341 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
343 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
344 /// do any post processing needed after all passes have run.
346 virtual bool doFinalization(Function &F) { return false; }
348 /// doFinalization - Virtual method overriden by subclasses to do any post
349 /// processing needed after all passes have run.
351 virtual bool doFinalization(Module &M) { return false; }
354 // To run this pass on a function, we simply call runOnBasicBlock once for
357 bool runOnFunction(Function &F);
359 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
362 virtual bool runPass(Module &M) { return false; }
363 virtual bool runPass(BasicBlock &BB);
365 virtual void assignPassManager(PMStack &PMS,
366 PassManagerType T = PMT_BasicBlockPassManager);
368 /// Return what kind of Pass Manager can manage this pass.
369 virtual PassManagerType getPotentialPassManagerType() const {
370 return PMT_BasicBlockPassManager;
375 /// Top level pass manager (see PasManager.cpp) maintains active Pass Managers
376 /// using PMStack. Each Pass implements assignPassManager() to connect itself
377 /// with appropriate manager. assignPassManager() walks PMStack to find
378 /// suitable manager.
380 /// PMStack is just a wrapper around standard deque that overrides pop() and
384 typedef std::deque<PMDataManager *>::reverse_iterator iterator;
385 iterator begin() { return S.rbegin(); }
386 iterator end() { return S.rend(); }
388 void handleLastUserOverflow();
391 inline PMDataManager *top() { return S.back(); }
393 inline bool empty() { return S.empty(); }
397 std::deque<PMDataManager *> S;
401 /// If the user specifies the -time-passes argument on an LLVM tool command line
402 /// then the value of this boolean will be true, otherwise false.
403 /// @brief This is the storage for the -time-passes option.
404 extern bool TimePassesIsEnabled;
406 } // End llvm namespace
408 // Include support files that contain important APIs commonly used by Passes,
409 // but that we want to separate out to make it easier to read the header files.
411 #include "llvm/PassSupport.h"
412 #include "llvm/PassAnalysisSupport.h"