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"
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 //===----------------------------------------------------------------------===//
69 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
70 /// interprocedural optimization or you do not fit into any of the more
71 /// constrained passes described below.
74 AnalysisResolver *Resolver; // Used to resolve analysis
76 // AnalysisImpls - This keeps track of which passes implement the interfaces
77 // that are required by the current pass (to implement getAnalysis()).
79 std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
81 void operator=(const Pass&); // DO NOT IMPLEMENT
82 Pass(const Pass &); // DO NOT IMPLEMENT
84 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {
85 assert(pid && "pid cannot be 0");
87 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) {
88 assert(pid && "pid cannot be 0");
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.
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 /// print - Print out the internal state of the pass. This is called by
104 /// Analyze to print out the contents of an analysis. Otherwise it is not
105 /// necessary to implement this method. Beware that the module pointer MAY be
106 /// null. This automatically forwards to a virtual function that does not
107 /// provide the Module* in case the analysis doesn't need it it can just be
110 virtual void print(std::ostream &O, const Module *M) const;
111 void print(std::ostream *O, const Module *M) const { if (O) print(*O, M); }
112 void dump() const; // dump - call print(std::cerr, 0);
114 /// Each pass is responsible for assigning a pass manager to itself.
115 /// PMS is the stack of available pass manager.
116 virtual void assignPassManager(PMStack &,
117 PassManagerType = PMT_Unknown) {}
118 /// Check if available pass managers are suitable for this pass or not.
119 virtual void preparePassManager(PMStack &) {}
121 /// Return what kind of Pass Manager can manage this pass.
122 virtual PassManagerType getPotentialPassManagerType() const {
126 // Access AnalysisResolver
127 inline void setResolver(AnalysisResolver *AR) {
128 assert (!Resolver && "Resolver is already set");
131 inline AnalysisResolver *getResolver() {
135 /// getAnalysisUsage - This function should be overriden by passes that need
136 /// analysis information to do their job. If a pass specifies that it uses a
137 /// particular analysis result to this function, it can then use the
138 /// getAnalysis<AnalysisType>() function, below.
140 virtual void getAnalysisUsage(AnalysisUsage &) const {
141 // By default, no analysis results are used, all are invalidated.
144 /// releaseMemory() - This member can be implemented by a pass if it wants to
145 /// be able to release its memory when it is no longer needed. The default
146 /// behavior of passes is to hold onto memory for the entire duration of their
147 /// lifetime (which is the entire compile time). For pipelined passes, this
148 /// is not a big deal because that memory gets recycled every time the pass is
149 /// invoked on another program unit. For IP passes, it is more important to
150 /// free memory when it is unused.
152 /// Optionally implement this function to release pass memory when it is no
155 virtual void releaseMemory() {}
157 /// verifyAnalysis() - This member can be implemented by a analysis pass to
158 /// check state of analysis information.
159 virtual void verifyAnalysis() const {}
161 // dumpPassStructure - Implement the -debug-passes=PassStructure option
162 virtual void dumpPassStructure(unsigned Offset = 0);
164 template<typename AnalysisClass>
165 static const PassInfo *getClassPassInfo() {
166 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
169 // lookupPassInfo - Return the pass info object for the specified pass class,
170 // or null if it is not known.
171 static const PassInfo *lookupPassInfo(intptr_t TI);
173 /// getAnalysisToUpdate<AnalysisType>() - This function is used by subclasses
174 /// to get to the analysis information that might be around that needs to be
175 /// updated. This is different than getAnalysis in that it can fail (ie the
176 /// analysis results haven't been computed), so should only be used if you
177 /// provide the capability to update an analysis that exists. This method is
178 /// often used by transformation APIs to update analysis results for a pass
179 /// automatically as the transform is performed.
181 template<typename AnalysisType>
182 AnalysisType *getAnalysisToUpdate() const; // Defined in PassAnalysisSupport.h
184 /// mustPreserveAnalysisID - This method serves the same function as
185 /// getAnalysisToUpdate, but works if you just have an AnalysisID. This
186 /// obviously cannot give you a properly typed instance of the class if you
187 /// don't have the class name available (use getAnalysisToUpdate if you do),
188 /// but it can tell you if you need to preserve the pass at least.
190 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
192 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
193 /// to the analysis information that they claim to use by overriding the
194 /// getAnalysisUsage function.
196 template<typename AnalysisType>
197 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
199 template<typename AnalysisType>
200 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
202 template<typename AnalysisType>
203 AnalysisType &getAnalysisID(const PassInfo *PI) const;
205 template<typename AnalysisType>
206 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
209 inline std::ostream &operator<<(std::ostream &OS, const Pass &P) {
210 P.print(OS, 0); return OS;
213 //===----------------------------------------------------------------------===//
214 /// ModulePass class - This class is used to implement unstructured
215 /// interprocedural optimizations and analyses. ModulePasses may do anything
216 /// they want to the program.
218 class ModulePass : public Pass {
220 /// runOnModule - Virtual method overriden by subclasses to process the module
221 /// being operated on.
222 virtual bool runOnModule(Module &M) = 0;
224 virtual void assignPassManager(PMStack &PMS,
225 PassManagerType T = PMT_ModulePassManager);
227 /// Return what kind of Pass Manager can manage this pass.
228 virtual PassManagerType getPotentialPassManagerType() const {
229 return PMT_ModulePassManager;
232 explicit ModulePass(intptr_t pid) : Pass(pid) {}
233 explicit ModulePass(const void *pid) : Pass(pid) {}
234 // Force out-of-line virtual method.
235 virtual ~ModulePass();
239 //===----------------------------------------------------------------------===//
240 /// ImmutablePass class - This class is used to provide information that does
241 /// not need to be run. This is useful for things like target information and
242 /// "basic" versions of AnalysisGroups.
244 class ImmutablePass : public ModulePass {
246 /// initializePass - This method may be overriden by immutable passes to allow
247 /// them to perform various initialization actions they require. This is
248 /// primarily because an ImmutablePass can "require" another ImmutablePass,
249 /// and if it does, the overloaded version of initializePass may get access to
250 /// these passes with getAnalysis<>.
252 virtual void initializePass() {}
254 /// ImmutablePasses are never run.
256 bool runOnModule(Module &) { return false; }
258 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
259 explicit ImmutablePass(const void *pid)
262 // Force out-of-line virtual method.
263 virtual ~ImmutablePass();
266 //===----------------------------------------------------------------------===//
267 /// FunctionPass class - This class is used to implement most global
268 /// optimizations. Optimizations should subclass this class if they meet the
269 /// following constraints:
271 /// 1. Optimizations are organized globally, i.e., a function at a time
272 /// 2. Optimizing a function does not cause the addition or removal of any
273 /// functions in the module
275 class FunctionPass : public Pass {
277 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
278 explicit FunctionPass(const void *pid) : Pass(pid) {}
280 /// doInitialization - Virtual method overridden by subclasses to do
281 /// any necessary per-module initialization.
283 virtual bool doInitialization(Module &) { return false; }
285 /// runOnFunction - Virtual method overriden by subclasses to do the
286 /// per-function processing of the pass.
288 virtual bool runOnFunction(Function &F) = 0;
290 /// doFinalization - Virtual method overriden by subclasses to do any post
291 /// processing needed after all passes have run.
293 virtual bool doFinalization(Module &) { return false; }
295 /// runOnModule - On a module, we run this pass by initializing,
296 /// ronOnFunction'ing once for every function in the module, then by
299 virtual bool runOnModule(Module &M);
301 /// run - On a function, we simply initialize, run the function, then
304 bool run(Function &F);
306 virtual void assignPassManager(PMStack &PMS,
307 PassManagerType T = PMT_FunctionPassManager);
309 /// Return what kind of Pass Manager can manage this pass.
310 virtual PassManagerType getPotentialPassManagerType() const {
311 return PMT_FunctionPassManager;
317 //===----------------------------------------------------------------------===//
318 /// BasicBlockPass class - This class is used to implement most local
319 /// optimizations. Optimizations should subclass this class if they
320 /// meet the following constraints:
321 /// 1. Optimizations are local, operating on either a basic block or
322 /// instruction at a time.
323 /// 2. Optimizations do not modify the CFG of the contained function, or any
324 /// other basic block in the function.
325 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
327 class BasicBlockPass : public Pass {
329 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
330 explicit BasicBlockPass(const void *pid) : Pass(pid) {}
332 /// doInitialization - Virtual method overridden by subclasses to do
333 /// any necessary per-module initialization.
335 virtual bool doInitialization(Module &) { return false; }
337 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
338 /// to do any necessary per-function initialization.
340 virtual bool doInitialization(Function &) { 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 &) { 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 &) { return false; }
358 // To run this pass on a function, we simply call runOnBasicBlock once for
361 bool runOnFunction(Function &F);
363 virtual void assignPassManager(PMStack &PMS,
364 PassManagerType T = PMT_BasicBlockPassManager);
366 /// Return what kind of Pass Manager can manage this pass.
367 virtual PassManagerType getPotentialPassManagerType() const {
368 return PMT_BasicBlockPassManager;
372 /// If the user specifies the -time-passes argument on an LLVM tool command line
373 /// then the value of this boolean will be true, otherwise false.
374 /// @brief This is the storage for the -time-passes option.
375 extern bool TimePassesIsEnabled;
377 } // End llvm namespace
379 // Include support files that contain important APIs commonly used by Passes,
380 // but that we want to separate out to make it easier to read the header files.
382 #include "llvm/PassSupport.h"
383 #include "llvm/PassAnalysisSupport.h"