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 class AnalysisResolver_New;
54 // AnalysisID - Use the PassInfo to identify a pass...
55 typedef const PassInfo* AnalysisID;
57 //===----------------------------------------------------------------------===//
58 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
59 /// interprocedural optimization or you do not fit into any of the more
60 /// constrained passes described below.
63 AnalysisResolver_New *Resolver_New; // Used to resolve analysis
64 const PassInfo *PassInfoCache;
66 // AnalysisImpls - This keeps track of which passes implement the interfaces
67 // that are required by the current pass (to implement getAnalysis()).
69 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
71 void operator=(const Pass&); // DO NOT IMPLEMENT
72 Pass(const Pass &); // DO NOT IMPLEMENT
74 Pass() : Resolver_New(0), PassInfoCache(0) {}
75 virtual ~Pass() {} // Destructor is virtual so we can be subclassed
77 /// getPassName - Return a nice clean name for a pass. This usually
78 /// implemented in terms of the name that is registered by one of the
79 /// Registration templates, but can be overloaded directly, and if nothing
80 /// else is available, C++ RTTI will be consulted to get a SOMEWHAT
81 /// intelligible name for the pass.
83 virtual const char *getPassName() const;
85 /// getPassInfo - Return the PassInfo data structure that corresponds to this
86 /// pass... If the pass has not been registered, this will return null.
88 const PassInfo *getPassInfo() const;
90 /// runPass - Run this pass, returning true if a modification was made to the
91 /// module argument. This should be implemented by all concrete subclasses.
93 virtual bool runPass(Module &M) { return false; }
94 virtual bool runPass(BasicBlock&) { return false; }
96 /// print - Print out the internal state of the pass. This is called by
97 /// Analyze to print out the contents of an analysis. Otherwise it is not
98 /// necessary to implement this method. Beware that the module pointer MAY be
99 /// null. This automatically forwards to a virtual function that does not
100 /// provide the Module* in case the analysis doesn't need it it can just be
103 virtual void print(std::ostream &O, const Module *M) const;
104 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
105 void dump() const; // dump - call print(std::cerr, 0);
107 // Access AnalysisResolver_New
108 inline void setResolver(AnalysisResolver_New *AR) { Resolver_New = AR; }
109 inline AnalysisResolver_New *getResolver() { return Resolver_New; }
111 /// getAnalysisUsage - This function should be overriden by passes that need
112 /// analysis information to do their job. If a pass specifies that it uses a
113 /// particular analysis result to this function, it can then use the
114 /// getAnalysis<AnalysisType>() function, below.
116 virtual void getAnalysisUsage(AnalysisUsage &Info) const {
117 // By default, no analysis results are used, all are invalidated.
120 /// releaseMemory() - This member can be implemented by a pass if it wants to
121 /// be able to release its memory when it is no longer needed. The default
122 /// behavior of passes is to hold onto memory for the entire duration of their
123 /// lifetime (which is the entire compile time). For pipelined passes, this
124 /// is not a big deal because that memory gets recycled every time the pass is
125 /// invoked on another program unit. For IP passes, it is more important to
126 /// free memory when it is unused.
128 /// Optionally implement this function to release pass memory when it is no
131 virtual void releaseMemory() {}
133 // dumpPassStructure - Implement the -debug-passes=PassStructure option
134 virtual void dumpPassStructure(unsigned Offset = 0);
137 // getPassInfo - Static method to get the pass information from a class name.
138 template<typename AnalysisClass>
139 static const PassInfo *getClassPassInfo() {
140 return lookupPassInfo(typeid(AnalysisClass));
143 // lookupPassInfo - Return the pass info object for the specified pass class,
144 // or null if it is not known.
145 static const PassInfo *lookupPassInfo(const std::type_info &TI);
147 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
148 /// to get to the analysis information that might be around that needs to be
149 /// updated. This is different than getAnalysis in that it can fail (ie the
150 /// analysis results haven't been computed), so should only be used if you
151 /// provide the capability to update an analysis that exists. This method is
152 /// often used by transformation APIs to update analysis results for a pass
153 /// automatically as the transform is performed.
155 template<typename AnalysisType>
156 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
158 /// mustPreserveAnalysisID - This method serves the same function as
159 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
160 /// obviously cannot give you a properly typed instance of the class if you
161 /// don't have the class name available (use getAnalysisToUpdate if you do),
162 /// but it can tell you if you need to preserve the pass at least.
164 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
166 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
167 /// to the analysis information that they claim to use by overriding the
168 /// getAnalysisUsage function.
170 template<typename AnalysisType>
171 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
173 template<typename AnalysisType>
174 AnalysisType &getAnalysisID(const PassInfo *PI) const;
177 template<typename Trait> friend class PassManagerT;
178 friend class ModulePassManager;
179 friend class FunctionPassManagerT;
180 friend class BasicBlockPassManager;
183 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
184 P.print(OS, 0); return OS;
187 //===----------------------------------------------------------------------===//
188 /// ModulePass class - This class is used to implement unstructured
189 /// interprocedural optimizations and analyses. ModulePasses may do anything
190 /// they want to the program.
192 class ModulePass : public Pass {
194 /// runOnModule - Virtual method overriden by subclasses to process the module
195 /// being operated on.
196 virtual bool runOnModule(Module &M) = 0;
198 virtual bool runPass(Module &M) { return runOnModule(M); }
199 virtual bool runPass(BasicBlock&) { return false; }
201 // Force out-of-line virtual method.
202 virtual ~ModulePass();
206 //===----------------------------------------------------------------------===//
207 /// ImmutablePass class - This class is used to provide information that does
208 /// not need to be run. This is useful for things like target information and
209 /// "basic" versions of AnalysisGroups.
211 class ImmutablePass : public ModulePass {
213 /// initializePass - This method may be overriden by immutable passes to allow
214 /// them to perform various initialization actions they require. This is
215 /// primarily because an ImmutablePass can "require" another ImmutablePass,
216 /// and if it does, the overloaded version of initializePass may get access to
217 /// these passes with getAnalysis<>.
219 virtual void initializePass() {}
221 /// ImmutablePasses are never run.
223 virtual bool runOnModule(Module &M) { return false; }
225 // Force out-of-line virtual method.
226 virtual ~ImmutablePass();
229 //===----------------------------------------------------------------------===//
230 /// FunctionPass class - This class is used to implement most global
231 /// optimizations. Optimizations should subclass this class if they meet the
232 /// following constraints:
234 /// 1. Optimizations are organized globally, i.e., a function at a time
235 /// 2. Optimizing a function does not cause the addition or removal of any
236 /// functions in the module
238 class FunctionPass : public ModulePass {
240 /// doInitialization - Virtual method overridden by subclasses to do
241 /// any necessary per-module initialization.
243 virtual bool doInitialization(Module &M) { return false; }
245 /// runOnFunction - Virtual method overriden by subclasses to do the
246 /// per-function processing of the pass.
248 virtual bool runOnFunction(Function &F) = 0;
250 /// doFinalization - Virtual method overriden by subclasses to do any post
251 /// processing needed after all passes have run.
253 virtual bool doFinalization(Module &M) { return false; }
255 /// runOnModule - On a module, we run this pass by initializing,
256 /// ronOnFunction'ing once for every function in the module, then by
259 virtual bool runOnModule(Module &M);
261 /// run - On a function, we simply initialize, run the function, then
264 bool run(Function &F);
270 //===----------------------------------------------------------------------===//
271 /// BasicBlockPass class - This class is used to implement most local
272 /// optimizations. Optimizations should subclass this class if they
273 /// meet the following constraints:
274 /// 1. Optimizations are local, operating on either a basic block or
275 /// instruction at a time.
276 /// 2. Optimizations do not modify the CFG of the contained function, or any
277 /// other basic block in the function.
278 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
280 class BasicBlockPass : public FunctionPass {
282 /// doInitialization - Virtual method overridden by subclasses to do
283 /// any necessary per-module initialization.
285 virtual bool doInitialization(Module &M) { return false; }
287 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
288 /// to do any necessary per-function initialization.
290 virtual bool doInitialization(Function &F) { return false; }
292 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
293 /// per-basicblock processing of the pass.
295 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
297 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
298 /// do any post processing needed after all passes have run.
300 virtual bool doFinalization(Function &F) { return false; }
302 /// doFinalization - Virtual method overriden by subclasses to do any post
303 /// processing needed after all passes have run.
305 virtual bool doFinalization(Module &M) { return false; }
308 // To run this pass on a function, we simply call runOnBasicBlock once for
311 bool runOnFunction(Function &F);
313 /// To run directly on the basic block, we initialize, runOnBasicBlock, then
316 virtual bool runPass(Module &M) { return false; }
317 virtual bool runPass(BasicBlock &BB);
321 /// If the user specifies the -time-passes argument on an LLVM tool command line
322 /// then the value of this boolean will be true, otherwise false.
323 /// @brief This is the storage for the -time-passes option.
324 extern bool TimePassesIsEnabled;
326 } // End llvm namespace
328 // Include support files that contain important APIs commonly used by Passes,
329 // but that we want to separate out to make it easier to read the header files.
331 #include "llvm/PassSupport.h"
332 #include "llvm/PassAnalysisSupport.h"