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);
77 /// Add the specified Pass class to the set of analyses preserved by this pass.
78 template<class PassClass>
79 AnalysisUsage &addPreserved() {
80 Preserved.push_back(&PassClass::ID);
84 /// Add the Pass with the specified argument string to the set of analyses
85 /// preserved by this pass. If no such Pass exists, do nothing. This can be
86 /// useful when a pass is trivially preserved, but may not be linked in. Be
87 /// careful about spelling!
88 AnalysisUsage &addPreserved(StringRef Arg);
90 /// Set by analyses that do not transform their input at all
91 void setPreservesAll() { PreservesAll = true; }
93 /// Determine whether a pass said it does not transform its input at all
94 bool getPreservesAll() const { return PreservesAll; }
96 /// This function should be called by the pass, iff they do not:
98 /// 1. Add or remove basic blocks from the function
99 /// 2. Modify terminator instructions in any way.
101 /// This function annotates the AnalysisUsage info object to say that analyses
102 /// that only depend on the CFG are preserved by this pass.
104 void setPreservesCFG();
106 const VectorType &getRequiredSet() const { return Required; }
107 const VectorType &getRequiredTransitiveSet() const {
108 return RequiredTransitive;
110 const VectorType &getPreservedSet() const { return Preserved; }
113 //===----------------------------------------------------------------------===//
114 /// AnalysisResolver - Simple interface used by Pass objects to pull all
115 /// analysis information out of pass manager that is responsible to manage
119 class AnalysisResolver {
121 AnalysisResolver() = delete;
124 explicit AnalysisResolver(PMDataManager &P) : PM(P) { }
126 inline PMDataManager &getPMDataManager() { return PM; }
128 /// Find pass that is implementing PI.
129 Pass *findImplPass(AnalysisID PI) {
130 Pass *ResultPass = nullptr;
131 for (unsigned i = 0; i < AnalysisImpls.size() ; ++i) {
132 if (AnalysisImpls[i].first == PI) {
133 ResultPass = AnalysisImpls[i].second;
140 /// Find pass that is implementing PI. Initialize pass for Function F.
141 Pass *findImplPass(Pass *P, AnalysisID PI, Function &F);
143 void addAnalysisImplsPair(AnalysisID PI, Pass *P) {
144 if (findImplPass(PI) == P)
146 std::pair<AnalysisID, Pass*> pir = std::make_pair(PI,P);
147 AnalysisImpls.push_back(pir);
150 /// Clear cache that is used to connect a pass to the the analysis (PassInfo).
151 void clearAnalysisImpls() {
152 AnalysisImpls.clear();
155 /// Return analysis result or null if it doesn't exist.
156 Pass *getAnalysisIfAvailable(AnalysisID ID, bool Direction) const;
159 /// This keeps track of which passes implements the interfaces that are
160 /// required by the current pass (to implement getAnalysis()).
161 std::vector<std::pair<AnalysisID, Pass*> > AnalysisImpls;
163 /// PassManager that is used to resolve analysis info
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>
176 AnalysisType *Pass::getAnalysisIfAvailable() const {
177 assert(Resolver && "Pass not resident in a PassManager object!");
179 const void *PI = &AnalysisType::ID;
181 Pass *ResultPass = Resolver->getAnalysisIfAvailable(PI, true);
182 if (!ResultPass) return nullptr;
184 // Because the AnalysisType may not be a subclass of pass (for
185 // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
186 // adjust the return pointer (because the class may multiply inherit, once
187 // from pass, once from AnalysisType).
188 return (AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
191 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
192 /// to the analysis information that they claim to use by overriding the
193 /// getAnalysisUsage function.
195 template<typename AnalysisType>
196 AnalysisType &Pass::getAnalysis() const {
197 assert(Resolver && "Pass has not been inserted into a PassManager object!");
198 return getAnalysisID<AnalysisType>(&AnalysisType::ID);
201 template<typename AnalysisType>
202 AnalysisType &Pass::getAnalysisID(AnalysisID PI) const {
203 assert(PI && "getAnalysis for unregistered pass!");
204 assert(Resolver&&"Pass has not been inserted into a PassManager object!");
205 // PI *must* appear in AnalysisImpls. Because the number of passes used
206 // should be a small number, we just do a linear search over a (dense)
208 Pass *ResultPass = Resolver->findImplPass(PI);
209 assert (ResultPass &&
210 "getAnalysis*() called on an analysis that was not "
211 "'required' by pass!");
213 // Because the AnalysisType may not be a subclass of pass (for
214 // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
215 // adjust the return pointer (because the class may multiply inherit, once
216 // from pass, once from AnalysisType).
217 return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
220 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
221 /// to the analysis information that they claim to use by overriding the
222 /// getAnalysisUsage function.
224 template<typename AnalysisType>
225 AnalysisType &Pass::getAnalysis(Function &F) {
226 assert(Resolver &&"Pass has not been inserted into a PassManager object!");
228 return getAnalysisID<AnalysisType>(&AnalysisType::ID, F);
231 template<typename AnalysisType>
232 AnalysisType &Pass::getAnalysisID(AnalysisID PI, Function &F) {
233 assert(PI && "getAnalysis for unregistered pass!");
234 assert(Resolver && "Pass has not been inserted into a PassManager object!");
235 // PI *must* appear in AnalysisImpls. Because the number of passes used
236 // should be a small number, we just do a linear search over a (dense)
238 Pass *ResultPass = Resolver->findImplPass(this, PI, F);
239 assert(ResultPass && "Unable to find requested analysis info");
241 // Because the AnalysisType may not be a subclass of pass (for
242 // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
243 // adjust the return pointer (because the class may multiply inherit, once
244 // from pass, once from AnalysisType).
245 return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
248 } // End llvm namespace