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"
46 class AnalysisResolver;
50 // AnalysisID - Use the PassInfo to identify a pass...
51 typedef const PassInfo* AnalysisID;
53 /// Different types of internal pass managers. External pass managers
54 /// (PassManager and FunctionPassManager) are not represented here.
55 /// Ordering of pass manager types is important here.
56 enum PassManagerType {
58 PMT_ModulePassManager = 1, /// MPPassManager
59 PMT_CallGraphPassManager, /// CGPassManager
60 PMT_FunctionPassManager, /// FPPassManager
61 PMT_LoopPassManager, /// LPPassManager
62 PMT_BasicBlockPassManager, /// BBPassManager
66 //===----------------------------------------------------------------------===//
67 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
68 /// interprocedural optimization or you do not fit into any of the more
69 /// constrained passes described below.
72 AnalysisResolver *Resolver; // Used to resolve analysis
75 void operator=(const Pass&); // DO NOT IMPLEMENT
76 Pass(const Pass &); // DO NOT IMPLEMENT
79 explicit Pass(intptr_t pid) : Resolver(0), PassID(pid) {
80 assert(pid && "pid cannot be 0");
82 explicit Pass(const void *pid) : Resolver(0), PassID((intptr_t)pid) {
83 assert(pid && "pid cannot be 0");
87 /// getPassName - Return a nice clean name for a pass. This usually
88 /// implemented in terms of the name that is registered by one of the
89 /// Registration templates, but can be overloaded directly.
91 virtual const char *getPassName() const;
93 /// getPassInfo - Return the PassInfo data structure that corresponds to this
94 /// pass... If the pass has not been registered, this will return null.
96 const PassInfo *getPassInfo() const;
98 /// print - Print out the internal state of the pass. This is called by
99 /// Analyze to print out the contents of an analysis. Otherwise it is not
100 /// necessary to implement this method. Beware that the module pointer MAY be
101 /// null. This automatically forwards to a virtual function that does not
102 /// provide the Module* in case the analysis doesn't need it it can just be
105 virtual void print(raw_ostream &O, const Module *M) const;
106 void dump() const; // dump - Print to stderr.
108 /// Each pass is responsible for assigning a pass manager to itself.
109 /// PMS is the stack of available pass manager.
110 virtual void assignPassManager(PMStack &,
111 PassManagerType = PMT_Unknown) {}
112 /// Check if available pass managers are suitable for this pass or not.
113 virtual void preparePassManager(PMStack &) {}
115 /// Return what kind of Pass Manager can manage this pass.
116 virtual PassManagerType getPotentialPassManagerType() const {
120 // Access AnalysisResolver
121 inline void setResolver(AnalysisResolver *AR) {
122 assert (!Resolver && "Resolver is already set");
125 inline AnalysisResolver *getResolver() {
129 /// getAnalysisUsage - This function should be overriden by passes that need
130 /// analysis information to do their job. If a pass specifies that it uses a
131 /// particular analysis result to this function, it can then use the
132 /// getAnalysis<AnalysisType>() function, below.
134 virtual void getAnalysisUsage(AnalysisUsage &) const {
135 // By default, no analysis results are used, all are invalidated.
138 /// releaseMemory() - This member can be implemented by a pass if it wants to
139 /// be able to release its memory when it is no longer needed. The default
140 /// behavior of passes is to hold onto memory for the entire duration of their
141 /// lifetime (which is the entire compile time). For pipelined passes, this
142 /// is not a big deal because that memory gets recycled every time the pass is
143 /// invoked on another program unit. For IP passes, it is more important to
144 /// free memory when it is unused.
146 /// Optionally implement this function to release pass memory when it is no
149 virtual void releaseMemory() {}
151 /// verifyAnalysis() - This member can be implemented by a analysis pass to
152 /// check state of analysis information.
153 virtual void verifyAnalysis() const {}
155 // dumpPassStructure - Implement the -debug-passes=PassStructure option
156 virtual void dumpPassStructure(unsigned Offset = 0);
158 template<typename AnalysisClass>
159 static const PassInfo *getClassPassInfo() {
160 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
163 // lookupPassInfo - Return the pass info object for the specified pass class,
164 // or null if it is not known.
165 static const PassInfo *lookupPassInfo(intptr_t TI);
167 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
168 /// get analysis information that might be around, for example to update it.
169 /// This is different than getAnalysis in that it can fail (if the analysis
170 /// results haven't been computed), so should only be used if you can handle
171 /// the case when the analysis is not available. This method is often used by
172 /// transformation APIs to update analysis results for a pass automatically as
173 /// the transform is performed.
175 template<typename AnalysisType> AnalysisType *
176 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
178 /// mustPreserveAnalysisID - This method serves the same function as
179 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
180 /// obviously cannot give you a properly typed instance of the class if you
181 /// don't have the class name available (use getAnalysisIfAvailable if you
182 /// do), but it can tell you if you need to preserve the pass at least.
184 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
186 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
187 /// to the analysis information that they claim to use by overriding the
188 /// getAnalysisUsage function.
190 template<typename AnalysisType>
191 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
193 template<typename AnalysisType>
194 AnalysisType &getAnalysis(Function &F); // Defined in PassanalysisSupport.h
196 template<typename AnalysisType>
197 AnalysisType &getAnalysisID(const PassInfo *PI) const;
199 template<typename AnalysisType>
200 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
204 //===----------------------------------------------------------------------===//
205 /// ModulePass class - This class is used to implement unstructured
206 /// interprocedural optimizations and analyses. ModulePasses may do anything
207 /// they want to the program.
209 class ModulePass : public Pass {
211 /// runOnModule - Virtual method overriden by subclasses to process the module
212 /// being operated on.
213 virtual bool runOnModule(Module &M) = 0;
215 virtual void assignPassManager(PMStack &PMS,
216 PassManagerType T = PMT_ModulePassManager);
218 /// Return what kind of Pass Manager can manage this pass.
219 virtual PassManagerType getPotentialPassManagerType() const {
220 return PMT_ModulePassManager;
223 explicit ModulePass(intptr_t pid) : Pass(pid) {}
224 explicit ModulePass(const void *pid) : Pass(pid) {}
225 // Force out-of-line virtual method.
226 virtual ~ModulePass();
230 //===----------------------------------------------------------------------===//
231 /// ImmutablePass class - This class is used to provide information that does
232 /// not need to be run. This is useful for things like target information and
233 /// "basic" versions of AnalysisGroups.
235 class ImmutablePass : public ModulePass {
237 /// initializePass - This method may be overriden by immutable passes to allow
238 /// them to perform various initialization actions they require. This is
239 /// primarily because an ImmutablePass can "require" another ImmutablePass,
240 /// and if it does, the overloaded version of initializePass may get access to
241 /// these passes with getAnalysis<>.
243 virtual void initializePass() {}
245 /// ImmutablePasses are never run.
247 bool runOnModule(Module &) { return false; }
249 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
250 explicit ImmutablePass(const void *pid)
253 // Force out-of-line virtual method.
254 virtual ~ImmutablePass();
257 //===----------------------------------------------------------------------===//
258 /// FunctionPass class - This class is used to implement most global
259 /// optimizations. Optimizations should subclass this class if they meet the
260 /// following constraints:
262 /// 1. Optimizations are organized globally, i.e., a function at a time
263 /// 2. Optimizing a function does not cause the addition or removal of any
264 /// functions in the module
266 class FunctionPass : public Pass {
268 explicit FunctionPass(intptr_t pid) : Pass(pid) {}
269 explicit FunctionPass(const void *pid) : Pass(pid) {}
271 /// doInitialization - Virtual method overridden by subclasses to do
272 /// any necessary per-module initialization.
274 virtual bool doInitialization(Module &M) { return false; }
276 /// runOnFunction - Virtual method overriden by subclasses to do the
277 /// per-function processing of the pass.
279 virtual bool runOnFunction(Function &F) = 0;
281 /// doFinalization - Virtual method overriden by subclasses to do any post
282 /// processing needed after all passes have run.
284 virtual bool doFinalization(Module &) { return false; }
286 /// runOnModule - On a module, we run this pass by initializing,
287 /// ronOnFunction'ing once for every function in the module, then by
290 virtual bool runOnModule(Module &M);
292 /// run - On a function, we simply initialize, run the function, then
295 bool run(Function &F);
297 virtual void assignPassManager(PMStack &PMS,
298 PassManagerType T = PMT_FunctionPassManager);
300 /// Return what kind of Pass Manager can manage this pass.
301 virtual PassManagerType getPotentialPassManagerType() const {
302 return PMT_FunctionPassManager;
308 //===----------------------------------------------------------------------===//
309 /// BasicBlockPass class - This class is used to implement most local
310 /// optimizations. Optimizations should subclass this class if they
311 /// meet the following constraints:
312 /// 1. Optimizations are local, operating on either a basic block or
313 /// instruction at a time.
314 /// 2. Optimizations do not modify the CFG of the contained function, or any
315 /// other basic block in the function.
316 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
318 class BasicBlockPass : public Pass {
320 explicit BasicBlockPass(intptr_t pid) : Pass(pid) {}
321 explicit BasicBlockPass(const void *pid) : Pass(pid) {}
323 /// doInitialization - Virtual method overridden by subclasses to do
324 /// any necessary per-module initialization.
326 virtual bool doInitialization(Module &M) { return false; }
328 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
329 /// to do any necessary per-function initialization.
331 virtual bool doInitialization(Function &) { return false; }
333 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
334 /// per-basicblock processing of the pass.
336 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
338 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
339 /// do any post processing needed after all passes have run.
341 virtual bool doFinalization(Function &) { return false; }
343 /// doFinalization - Virtual method overriden by subclasses to do any post
344 /// processing needed after all passes have run.
346 virtual bool doFinalization(Module &) { return false; }
349 // To run this pass on a function, we simply call runOnBasicBlock once for
352 bool runOnFunction(Function &F);
354 virtual void assignPassManager(PMStack &PMS,
355 PassManagerType T = PMT_BasicBlockPassManager);
357 /// Return what kind of Pass Manager can manage this pass.
358 virtual PassManagerType getPotentialPassManagerType() const {
359 return PMT_BasicBlockPassManager;
363 /// If the user specifies the -time-passes argument on an LLVM tool command line
364 /// then the value of this boolean will be true, otherwise false.
365 /// @brief This is the storage for the -time-passes option.
366 extern bool TimePassesIsEnabled;
368 } // End llvm namespace
370 // Include support files that contain important APIs commonly used by Passes,
371 // but that we want to separate out to make it easier to read the header files.
373 #include "llvm/PassSupport.h"
374 #include "llvm/PassAnalysisSupport.h"