1 //===- llvm/PassAnalysisSupport.h - Analysis Pass Support code --*- 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 stuff that is used to define and "use" Analysis Passes.
11 // This file is automatically #included by Pass.h, so:
13 // NO .CPP FILES SHOULD INCLUDE THIS FILE DIRECTLY
15 // Instead, #include Pass.h
17 //===----------------------------------------------------------------------===//
19 #ifndef LLVM_PASSANALYSISSUPPORT_H
20 #define LLVM_PASSANALYSISSUPPORT_H
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/ADT/StringRef.h"
24 #include "llvm/Pass.h"
29 //===----------------------------------------------------------------------===//
30 /// Represent the analysis usage information of a pass. This tracks analyses
31 /// that the pass REQUIRES (must be available when the pass runs), REQUIRES
32 /// TRANSITIVE (must be available throughout the lifetime of the pass), and
33 /// analyses that the pass PRESERVES (the pass does not invalidate the results
34 /// of these analyses). This information is provided by a pass to the Pass
35 /// infrastructure through the getAnalysisUsage virtual function.
39 typedef SmallVector<AnalysisID, 32> VectorType;
42 /// Sets of analyses required and preserved by a pass
43 VectorType Required, RequiredTransitive, Preserved;
47 AnalysisUsage() : PreservesAll(false) {}
50 /// Add the specified ID to the required set of the usage info for a pass.
51 AnalysisUsage &addRequiredID(const void *ID);
52 AnalysisUsage &addRequiredID(char &ID);
53 template<class PassClass>
54 AnalysisUsage &addRequired() {
55 return addRequiredID(PassClass::ID);
58 AnalysisUsage &addRequiredTransitiveID(char &ID);
59 template<class PassClass>
60 AnalysisUsage &addRequiredTransitive() {
61 return addRequiredTransitiveID(PassClass::ID);
66 /// Add the specified ID to the set of analyses preserved by this pass.
67 AnalysisUsage &addPreservedID(const void *ID) {
68 Preserved.push_back(ID);
71 AnalysisUsage &addPreservedID(char &ID) {
72 Preserved.push_back(&ID);
75 /// Add the specified Pass class to the set of analyses preserved by this pass.
76 template<class PassClass>
77 AnalysisUsage &addPreserved() {
78 Preserved.push_back(&PassClass::ID);
83 /// Add the Pass with the specified argument string to the set of analyses
84 /// preserved by this pass. If no such Pass exists, do nothing. This can be
85 /// useful when a pass is trivially preserved, but may not be linked in. Be
86 /// careful about spelling!
87 AnalysisUsage &addPreserved(StringRef Arg);
89 /// Set by analyses that do not transform their input at all
90 void setPreservesAll() { PreservesAll = true; }
92 /// Determine whether a pass said it does not transform its input at all
93 bool getPreservesAll() const { return PreservesAll; }
95 /// This function should be called by the pass, iff they do not:
97 /// 1. Add or remove basic blocks from the function
98 /// 2. Modify terminator instructions in any way.
100 /// This function annotates the AnalysisUsage info object to say that analyses
101 /// that only depend on the CFG are preserved by this pass.
103 void setPreservesCFG();
105 const VectorType &getRequiredSet() const { return Required; }
106 const VectorType &getRequiredTransitiveSet() const {
107 return RequiredTransitive;
109 const VectorType &getPreservedSet() const { return Preserved; }
112 //===----------------------------------------------------------------------===//
113 /// AnalysisResolver - Simple interface used by Pass objects to pull all
114 /// analysis information out of pass manager that is responsible to manage
118 class AnalysisResolver {
120 AnalysisResolver() = delete;
123 explicit AnalysisResolver(PMDataManager &P) : PM(P) { }
125 inline PMDataManager &getPMDataManager() { return PM; }
127 /// Find pass that is implementing PI.
128 Pass *findImplPass(AnalysisID PI) {
129 Pass *ResultPass = nullptr;
130 for (unsigned i = 0; i < AnalysisImpls.size() ; ++i) {
131 if (AnalysisImpls[i].first == PI) {
132 ResultPass = AnalysisImpls[i].second;
139 /// Find pass that is implementing PI. Initialize pass for Function F.
140 Pass *findImplPass(Pass *P, AnalysisID PI, Function &F);
142 void addAnalysisImplsPair(AnalysisID PI, Pass *P) {
143 if (findImplPass(PI) == P)
145 std::pair<AnalysisID, Pass*> pir = std::make_pair(PI,P);
146 AnalysisImpls.push_back(pir);
149 /// Clear cache that is used to connect a pass to the the analysis (PassInfo).
150 void clearAnalysisImpls() {
151 AnalysisImpls.clear();
154 /// Return analysis result or null if it doesn't exist.
155 Pass *getAnalysisIfAvailable(AnalysisID ID, bool Direction) const;
158 /// This keeps track of which passes implements the interfaces that are
159 /// required by the current pass (to implement getAnalysis()).
160 std::vector<std::pair<AnalysisID, Pass*> > AnalysisImpls;
162 /// PassManager that is used to resolve analysis info
166 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
167 /// get analysis information that might be around, for example to update it.
168 /// This is different than getAnalysis in that it can fail (if the analysis
169 /// results haven't been computed), so should only be used if you can handle
170 /// the case when the analysis is not available. This method is often used by
171 /// transformation APIs to update analysis results for a pass automatically as
172 /// the transform is performed.
174 template<typename AnalysisType>
175 AnalysisType *Pass::getAnalysisIfAvailable() const {
176 assert(Resolver && "Pass not resident in a PassManager object!");
178 const void *PI = &AnalysisType::ID;
180 Pass *ResultPass = Resolver->getAnalysisIfAvailable(PI, true);
181 if (!ResultPass) return nullptr;
183 // Because the AnalysisType may not be a subclass of pass (for
184 // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
185 // adjust the return pointer (because the class may multiply inherit, once
186 // from pass, once from AnalysisType).
187 return (AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
190 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
191 /// to the analysis information that they claim to use by overriding the
192 /// getAnalysisUsage function.
194 template<typename AnalysisType>
195 AnalysisType &Pass::getAnalysis() const {
196 assert(Resolver && "Pass has not been inserted into a PassManager object!");
197 return getAnalysisID<AnalysisType>(&AnalysisType::ID);
200 template<typename AnalysisType>
201 AnalysisType &Pass::getAnalysisID(AnalysisID PI) const {
202 assert(PI && "getAnalysis for unregistered pass!");
203 assert(Resolver&&"Pass has not been inserted into a PassManager object!");
204 // PI *must* appear in AnalysisImpls. Because the number of passes used
205 // should be a small number, we just do a linear search over a (dense)
207 Pass *ResultPass = Resolver->findImplPass(PI);
208 assert (ResultPass &&
209 "getAnalysis*() called on an analysis that was not "
210 "'required' by pass!");
212 // Because the AnalysisType may not be a subclass of pass (for
213 // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
214 // adjust the return pointer (because the class may multiply inherit, once
215 // from pass, once from AnalysisType).
216 return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
219 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
220 /// to the analysis information that they claim to use by overriding the
221 /// getAnalysisUsage function.
223 template<typename AnalysisType>
224 AnalysisType &Pass::getAnalysis(Function &F) {
225 assert(Resolver &&"Pass has not been inserted into a PassManager object!");
227 return getAnalysisID<AnalysisType>(&AnalysisType::ID, F);
230 template<typename AnalysisType>
231 AnalysisType &Pass::getAnalysisID(AnalysisID PI, Function &F) {
232 assert(PI && "getAnalysis for unregistered pass!");
233 assert(Resolver && "Pass has not been inserted into a PassManager object!");
234 // PI *must* appear in AnalysisImpls. Because the number of passes used
235 // should be a small number, we just do a linear search over a (dense)
237 Pass *ResultPass = Resolver->findImplPass(this, PI, F);
238 assert(ResultPass && "Unable to find requested analysis info");
240 // Because the AnalysisType may not be a subclass of pass (for
241 // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
242 // adjust the return pointer (because the class may multiply inherit, once
243 // from pass, once from AnalysisType).
244 return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
247 } // End llvm namespace