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 template<class Trait> class PassManagerT;
49 class BasicBlockPassManager;
50 class FunctionPassManagerT;
51 class ModulePassManager;
52 struct AnalysisResolver;
53 class AnalysisResolver_New;
55 // AnalysisID - Use the PassInfo to identify a pass...
56 typedef const PassInfo* AnalysisID;
58 //===----------------------------------------------------------------------===//
59 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
60 /// interprocedural optimization or you do not fit into any of the more
61 /// constrained passes described below.
64 friend struct AnalysisResolver;
65 AnalysisResolver *Resolver; // AnalysisResolver this pass is owned by...
66 AnalysisResolver_New *Resolver_New; // Used to resolve analysis
67 const PassInfo *PassInfoCache;
69 // AnalysisImpls - This keeps track of which passes implement the interfaces
70 // that are required by the current pass (to implement getAnalysis()).
72 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
74 void operator=(const Pass&); // DO NOT IMPLEMENT
75 Pass(const Pass &); // DO NOT IMPLEMENT
77 Pass() : Resolver(0), Resolver_New(0), PassInfoCache(0) {}
78 virtual ~Pass() {} // Destructor is virtual so we can be subclassed
80 /// getPassName - Return a nice clean name for a pass. This usually
81 /// implemented in terms of the name that is registered by one of the
82 /// Registration templates, but can be overloaded directly, and if nothing
83 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
84 /// intelligible name for the pass.
86 virtual const char *getPassName() const;
88 /// getPassInfo - Return the PassInfo data structure that corresponds to this
89 /// pass... If the pass has not been registered, this will return null.
91 const PassInfo *getPassInfo() const;
93 /// runPass - Run this pass, returning true if a modification was made to the
94 /// module argument. This should be implemented by all concrete subclasses.
96 virtual bool runPass(Module &M) { return false; }
97 virtual bool runPass(BasicBlock&) { return false; }
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 void print(OStream &O, const Module *M) const {
107 if (O.stream()) print(*O.stream(), M);
109 virtual void print(std::ostream &O, const Module *M) const;
110 void dump() const; // dump - call print(std::cerr, 0);
112 // Access AnalysisResolver_New
113 inline void setResolver(AnalysisResolver_New *AR) { Resolver_New = AR; }
114 inline AnalysisResolver_New *getResolver() { return Resolver_New; }
116 /// getAnalysisUsage - This function should be overriden by passes that need
117 /// analysis information to do their job. If a pass specifies that it uses a
118 /// particular analysis result to this function, it can then use the
119 /// getAnalysis<AnalysisType>() function, below.
121 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
122 // By default, no analysis results are used, all are invalidated.
125 /// releaseMemory() - This member can be implemented by a pass if it wants to
126 /// be able to release its memory when it is no longer needed. The default
127 /// behavior of passes is to hold onto memory for the entire duration of their
128 /// lifetime (which is the entire compile time). For pipelined passes, this
129 /// is not a big deal because that memory gets recycled every time the pass is
130 /// invoked on another program unit. For IP passes, it is more important to
131 /// free memory when it is unused.
133 /// Optionally implement this function to release pass memory when it is no
136 virtual void releaseMemory() {}
138 // dumpPassStructure - Implement the -debug-passes=PassStructure option
139 virtual void dumpPassStructure(unsigned Offset = 0);
142 // getPassInfo - Static method to get the pass information from a class name.
143 template<typename AnalysisClass>
144 static const PassInfo *getClassPassInfo() {
145 return lookupPassInfo(typeid(AnalysisClass));
148 // lookupPassInfo - Return the pass info object for the specified pass class,
149 // or null if it is not known.
150 static const PassInfo *lookupPassInfo(const std::type_info &TI);
152 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
153 /// to get to the analysis information that might be around that needs to be
154 /// updated. This is different than getAnalysis in that it can fail (ie the
155 /// analysis results haven't been computed), so should only be used if you
156 /// provide the capability to update an analysis that exists. This method is
157 /// often used by transformation APIs to update analysis results for a pass
158 /// automatically as the transform is performed.
160 template<typename AnalysisType>
161 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
163 /// mustPreserveAnalysisID - This method serves the same function as
164 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
165 /// obviously cannot give you a properly typed instance of the class if you
166 /// don't have the class name available (use getAnalysisToUpdate if you do),
167 /// but it can tell you if you need to preserve the pass at least.
169 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
171 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
172 /// to the analysis information that they claim to use by overriding the
173 /// getAnalysisUsage function.
175 template<typename AnalysisType>
176 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
178 template<typename AnalysisType>
179 AnalysisType &getAnalysisID(const PassInfo *PI) const;
182 template<typename Trait> friend class PassManagerT;
183 friend class ModulePassManager;
184 friend class FunctionPassManagerT;
185 friend class BasicBlockPassManager;
188 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
189 P.print(OS, 0); return OS;
192 //===----------------------------------------------------------------------===//
193 /// ModulePass class - This class is used to implement unstructured
194 /// interprocedural optimizations and analyses. ModulePasses may do anything
195 /// they want to the program.
197 class ModulePass : public Pass {
199 /// runOnModule - Virtual method overriden by subclasses to process the module
200 /// being operated on.
201 virtual bool runOnModule(Module &M) = 0;
203 virtual bool runPass(Module &M) { return runOnModule(M); }
204 virtual bool runPass(BasicBlock&) { return false; }
206 virtual void addToPassManager(ModulePassManager *PM, AnalysisUsage &AU);
210 //===----------------------------------------------------------------------===//
211 /// ImmutablePass class - This class is used to provide information that does
212 /// not need to be run. This is useful for things like target information and
213 /// "basic" versions of AnalysisGroups.
215 class ImmutablePass : public ModulePass {
217 /// initializePass - This method may be overriden by immutable passes to allow
218 /// them to perform various initialization actions they require. This is
219 /// primarily because an ImmutablePass can "require" another ImmutablePass,
220 /// and if it does, the overloaded version of initializePass may get access to
221 /// these passes with getAnalysis<>.
223 virtual void initializePass() {}
225 /// ImmutablePasses are never run.
227 virtual bool runOnModule(Module &M) { return false; }
230 template<typename Trait> friend class PassManagerT;
231 friend class ModulePassManager;
232 virtual void addToPassManager(ModulePassManager *PM, AnalysisUsage &AU);
235 //===----------------------------------------------------------------------===//
236 /// FunctionPass class - This class is used to implement most global
237 /// optimizations. Optimizations should subclass this class if they meet the
238 /// following constraints:
240 /// 1. Optimizations are organized globally, i.e., a function at a time
241 /// 2. Optimizing a function does not cause the addition or removal of any
242 /// functions in the module
244 class FunctionPass : public ModulePass {
246 /// doInitialization - Virtual method overridden by subclasses to do
247 /// any necessary per-module initialization.
249 virtual bool doInitialization(Module &M) { return false; }
251 /// runOnFunction - Virtual method overriden by subclasses to do the
252 /// per-function processing of the pass.
254 virtual bool runOnFunction(Function &F) = 0;
256 /// doFinalization - Virtual method overriden by subclasses to do any post
257 /// processing needed after all passes have run.
259 virtual bool doFinalization(Module &M) { return false; }
261 /// runOnModule - On a module, we run this pass by initializing,
262 /// ronOnFunction'ing once for every function in the module, then by
265 virtual bool runOnModule(Module &M);
267 /// run - On a function, we simply initialize, run the function, then
270 bool run(Function &F);
273 template<typename Trait> friend class PassManagerT;
274 friend class ModulePassManager;
275 friend class FunctionPassManagerT;
276 friend class BasicBlockPassManager;
277 virtual void addToPassManager(ModulePassManager *PM, AnalysisUsage &AU);
278 virtual void addToPassManager(FunctionPassManagerT *PM, AnalysisUsage &AU);
283 //===----------------------------------------------------------------------===//
284 /// BasicBlockPass class - This class is used to implement most local
285 /// optimizations. Optimizations should subclass this class if they
286 /// meet the following constraints:
287 /// 1. Optimizations are local, operating on either a basic block or
288 /// instruction at a time.
289 /// 2. Optimizations do not modify the CFG of the contained function, or any
290 /// other basic block in the function.
291 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
293 class BasicBlockPass : public FunctionPass {
295 /// doInitialization - Virtual method overridden by subclasses to do
296 /// any necessary per-module initialization.
298 virtual bool doInitialization(Module &M) { return false; }
300 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
301 /// to do any necessary per-function initialization.
303 virtual bool doInitialization(Function &F) { return false; }
305 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
306 /// per-basicblock processing of the pass.
308 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
310 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
311 /// do any post processing needed after all passes have run.
313 virtual bool doFinalization(Function &F) { return false; }
315 /// doFinalization - Virtual method overriden by subclasses to do any post
316 /// processing needed after all passes have run.
318 virtual bool doFinalization(Module &M) { return false; }
321 // To run this pass on a function, we simply call runOnBasicBlock once for
324 bool runOnFunction(Function &F);
326 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
329 virtual bool runPass(Module &M) { return false; }
330 virtual bool runPass(BasicBlock &BB);
333 template<typename Trait> friend class PassManagerT;
334 friend class FunctionPassManagerT;
335 friend class BasicBlockPassManager;
336 virtual void addToPassManager(ModulePassManager *PM, AnalysisUsage &AU) {
337 FunctionPass::addToPassManager(PM, AU);
339 virtual void addToPassManager(FunctionPassManagerT *PM, AnalysisUsage &AU);
340 virtual void addToPassManager(BasicBlockPassManager *PM,AnalysisUsage &AU);
343 /// If the user specifies the -time-passes argument on an LLVM tool command line
344 /// then the value of this boolean will be true, otherwise false.
345 /// @brief This is the storage for the -time-passes option.
346 extern bool TimePassesIsEnabled;
348 } // End llvm namespace
350 // Include support files that contain important APIs commonly used by Passes,
351 // but that we want to separate out to make it easier to read the header files.
353 #include "llvm/PassSupport.h"
354 #include "llvm/PassAnalysisSupport.h"