LLVM  6.0.0svn
PassAnalysisSupport.h
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1 //===- llvm/PassAnalysisSupport.h - Analysis Pass Support code --*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines stuff that is used to define and "use" Analysis Passes.
11 // This file is automatically #included by Pass.h, so:
12 //
13 // NO .CPP FILES SHOULD INCLUDE THIS FILE DIRECTLY
14 //
15 // Instead, #include Pass.h
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #ifndef LLVM_PASSANALYSISSUPPORT_H
20 #define LLVM_PASSANALYSISSUPPORT_H
21 
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/ADT/StringRef.h"
24 #include <cassert>
25 #include <utility>
26 #include <vector>
27 
28 namespace llvm {
29 
30 class Function;
31 class Pass;
32 class PMDataManager;
33 
34 //===----------------------------------------------------------------------===//
35 /// Represent the analysis usage information of a pass. This tracks analyses
36 /// that the pass REQUIRES (must be available when the pass runs), REQUIRES
37 /// TRANSITIVE (must be available throughout the lifetime of the pass), and
38 /// analyses that the pass PRESERVES (the pass does not invalidate the results
39 /// of these analyses). This information is provided by a pass to the Pass
40 /// infrastructure through the getAnalysisUsage virtual function.
41 ///
43 public:
45 
46 private:
47  /// Sets of analyses required and preserved by a pass
48  // TODO: It's not clear that SmallVector is an appropriate data structure for
49  // this usecase. The sizes were picked to minimize wasted space, but are
50  // otherwise fairly meaningless.
52  SmallVector<AnalysisID, 2> RequiredTransitive;
55  bool PreservesAll = false;
56 
57 public:
58  AnalysisUsage() = default;
59 
60  ///@{
61  /// Add the specified ID to the required set of the usage info for a pass.
62  AnalysisUsage &addRequiredID(const void *ID);
64  template<class PassClass>
67  }
68 
70  template<class PassClass>
73  }
74  ///@}
75 
76  ///@{
77  /// Add the specified ID to the set of analyses preserved by this pass.
78  AnalysisUsage &addPreservedID(const void *ID) {
79  Preserved.push_back(ID);
80  return *this;
81  }
83  Preserved.push_back(&ID);
84  return *this;
85  }
86  /// Add the specified Pass class to the set of analyses preserved by this pass.
87  template<class PassClass>
89  Preserved.push_back(&PassClass::ID);
90  return *this;
91  }
92  ///@}
93 
94  ///@{
95  /// Add the specified ID to the set of analyses used by this pass if they are
96  /// available..
98  Used.push_back(ID);
99  return *this;
100  }
102  Used.push_back(&ID);
103  return *this;
104  }
105  /// Add the specified Pass class to the set of analyses used by this pass.
106  template<class PassClass>
108  Used.push_back(&PassClass::ID);
109  return *this;
110  }
111  ///@}
112 
113  /// Add the Pass with the specified argument string to the set of analyses
114  /// preserved by this pass. If no such Pass exists, do nothing. This can be
115  /// useful when a pass is trivially preserved, but may not be linked in. Be
116  /// careful about spelling!
118 
119  /// Set by analyses that do not transform their input at all
120  void setPreservesAll() { PreservesAll = true; }
121 
122  /// Determine whether a pass said it does not transform its input at all
123  bool getPreservesAll() const { return PreservesAll; }
124 
125  /// This function should be called by the pass, iff they do not:
126  ///
127  /// 1. Add or remove basic blocks from the function
128  /// 2. Modify terminator instructions in any way.
129  ///
130  /// This function annotates the AnalysisUsage info object to say that analyses
131  /// that only depend on the CFG are preserved by this pass.
132  void setPreservesCFG();
133 
134  const VectorType &getRequiredSet() const { return Required; }
136  return RequiredTransitive;
137  }
138  const VectorType &getPreservedSet() const { return Preserved; }
139  const VectorType &getUsedSet() const { return Used; }
140 };
141 
142 //===----------------------------------------------------------------------===//
143 /// AnalysisResolver - Simple interface used by Pass objects to pull all
144 /// analysis information out of pass manager that is responsible to manage
145 /// the pass.
146 ///
148 public:
149  AnalysisResolver() = delete;
150  explicit AnalysisResolver(PMDataManager &P) : PM(P) {}
151 
152  PMDataManager &getPMDataManager() { return PM; }
153 
154  /// Find pass that is implementing PI.
156  Pass *ResultPass = nullptr;
157  for (const auto &AnalysisImpl : AnalysisImpls) {
158  if (AnalysisImpl.first == PI) {
159  ResultPass = AnalysisImpl.second;
160  break;
161  }
162  }
163  return ResultPass;
164  }
165 
166  /// Find pass that is implementing PI. Initialize pass for Function F.
167  Pass *findImplPass(Pass *P, AnalysisID PI, Function &F);
168 
170  if (findImplPass(PI) == P)
171  return;
172  std::pair<AnalysisID, Pass*> pir = std::make_pair(PI,P);
173  AnalysisImpls.push_back(pir);
174  }
175 
176  /// Clear cache that is used to connect a pass to the the analysis (PassInfo).
178  AnalysisImpls.clear();
179  }
180 
181  /// Return analysis result or null if it doesn't exist.
182  Pass *getAnalysisIfAvailable(AnalysisID ID, bool Direction) const;
183 
184 private:
185  /// This keeps track of which passes implements the interfaces that are
186  /// required by the current pass (to implement getAnalysis()).
187  std::vector<std::pair<AnalysisID, Pass *>> AnalysisImpls;
188 
189  /// PassManager that is used to resolve analysis info
190  PMDataManager &PM;
191 };
192 
193 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
194 /// get analysis information that might be around, for example to update it.
195 /// This is different than getAnalysis in that it can fail (if the analysis
196 /// results haven't been computed), so should only be used if you can handle
197 /// the case when the analysis is not available. This method is often used by
198 /// transformation APIs to update analysis results for a pass automatically as
199 /// the transform is performed.
200 template<typename AnalysisType>
201 AnalysisType *Pass::getAnalysisIfAvailable() const {
202  assert(Resolver && "Pass not resident in a PassManager object!");
203 
204  const void *PI = &AnalysisType::ID;
205 
206  Pass *ResultPass = Resolver->getAnalysisIfAvailable(PI, true);
207  if (!ResultPass) return nullptr;
208 
209  // Because the AnalysisType may not be a subclass of pass (for
210  // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
211  // adjust the return pointer (because the class may multiply inherit, once
212  // from pass, once from AnalysisType).
213  return (AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
214 }
215 
216 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
217 /// to the analysis information that they claim to use by overriding the
218 /// getAnalysisUsage function.
219 template<typename AnalysisType>
220 AnalysisType &Pass::getAnalysis() const {
221  assert(Resolver && "Pass has not been inserted into a PassManager object!");
222  return getAnalysisID<AnalysisType>(&AnalysisType::ID);
223 }
224 
225 template<typename AnalysisType>
226 AnalysisType &Pass::getAnalysisID(AnalysisID PI) const {
227  assert(PI && "getAnalysis for unregistered pass!");
228  assert(Resolver&&"Pass has not been inserted into a PassManager object!");
229  // PI *must* appear in AnalysisImpls. Because the number of passes used
230  // should be a small number, we just do a linear search over a (dense)
231  // vector.
232  Pass *ResultPass = Resolver->findImplPass(PI);
233  assert(ResultPass &&
234  "getAnalysis*() called on an analysis that was not "
235  "'required' by pass!");
236 
237  // Because the AnalysisType may not be a subclass of pass (for
238  // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
239  // adjust the return pointer (because the class may multiply inherit, once
240  // from pass, once from AnalysisType).
241  return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
242 }
243 
244 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
245 /// to the analysis information that they claim to use by overriding the
246 /// getAnalysisUsage function.
247 template<typename AnalysisType>
248 AnalysisType &Pass::getAnalysis(Function &F) {
249  assert(Resolver &&"Pass has not been inserted into a PassManager object!");
250 
251  return getAnalysisID<AnalysisType>(&AnalysisType::ID, F);
252 }
253 
254 template<typename AnalysisType>
256  assert(PI && "getAnalysis for unregistered pass!");
257  assert(Resolver && "Pass has not been inserted into a PassManager object!");
258  // PI *must* appear in AnalysisImpls. Because the number of passes used
259  // should be a small number, we just do a linear search over a (dense)
260  // vector.
261  Pass *ResultPass = Resolver->findImplPass(this, PI, F);
262  assert(ResultPass && "Unable to find requested analysis info");
263 
264  // Because the AnalysisType may not be a subclass of pass (for
265  // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
266  // adjust the return pointer (because the class may multiply inherit, once
267  // from pass, once from AnalysisType).
268  return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
269 }
270 
271 } // end namespace llvm
272 
273 #endif // LLVM_PASSANALYSISSUPPORT_H
Pass interface - Implemented by all &#39;passes&#39;.
Definition: Pass.h:81
void push_back(const T &Elt)
Definition: SmallVector.h:212
AnalysisUsage & addPreserved()
Add the specified Pass class to the set of analyses preserved by this pass.
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
F(f)
const VectorType & getUsedSet() const
const VectorType & getRequiredSet() const
AnalysisResolver - Simple interface used by Pass objects to pull all analysis information out of pass...
AnalysisUsage & addRequired()
AnalysisUsage & addPreservedID(char &ID)
const VectorType & getPreservedSet() const
AnalysisUsage & addUsedIfAvailableID(char &ID)
AnalysisUsage & addPreservedID(const void *ID)
AnalysisType & getAnalysis() const
getAnalysis<AnalysisType>() - This function is used by subclasses to get to the analysis information ...
AnalysisResolver(PMDataManager &P)
AnalysisType & getAnalysisID(AnalysisID PI) const
#define P(N)
Represent the analysis usage information of a pass.
AnalysisUsage & addUsedIfAvailableID(const void *ID)
print lazy value Lazy Value Info Printer Pass
AnalysisUsage()=default
AnalysisUsage & addRequiredID(const void *ID)
Definition: Pass.cpp:298
void addAnalysisImplsPair(AnalysisID PI, Pass *P)
void setPreservesCFG()
This function should be called by the pass, iff they do not:
Definition: Pass.cpp:285
const void * AnalysisID
Definition: Pass.h:49
void clearAnalysisImpls()
Clear cache that is used to connect a pass to the the analysis (PassInfo).
Pass * findImplPass(AnalysisID PI)
Find pass that is implementing PI.
void setPreservesAll()
Set by analyses that do not transform their input at all.
const VectorType & getRequiredTransitiveSet() const
amdgpu Simplify well known AMD library false Value Value * Arg
PMDataManager & getPMDataManager()
AnalysisUsage & addRequiredTransitiveID(char &ID)
Definition: Pass.cpp:308
AnalysisUsage & addRequiredTransitive()
PMDataManager provides the common place to manage the analysis data used by pass managers.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
AnalysisUsage & addUsedIfAvailable()
Add the specified Pass class to the set of analyses used by this pass.
AnalysisType * getAnalysisIfAvailable() const
getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to get analysis information tha...
virtual void * getAdjustedAnalysisPointer(AnalysisID ID)
getAdjustedAnalysisPointer - This method is used when a pass implements an analysis interface through...
Definition: Pass.cpp:103
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
bool getPreservesAll() const
Determine whether a pass said it does not transform its input at all.