include/llvm/PassAnalysisSupport.h

   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_PASS_ANALYSIS_SUPPORT_H
  20 #define LLVM_PASS_ANALYSIS_SUPPORT_H
  21
  22 #include "llvm/Pass.h"
  23 #include "llvm/ADT/SmallVector.h"
  24 #include "llvm/ADT/StringRef.h"
  25 #include <vector>
  26
  27 namespace llvm {
  28
  29 //===----------------------------------------------------------------------===//
  30 // AnalysisUsage - Represent the analysis usage information of a pass.  This
  31 // tracks analyses that the pass REQUIRES (must be available when the pass
  32 // runs), REQUIRES TRANSITIVE (must be available throughout the lifetime of the
  33 // pass), and analyses that the pass PRESERVES (the pass does not invalidate the
  34 // results of these analyses).  This information is provided by a pass to the
  35 // Pass infrastructure through the getAnalysisUsage virtual function.
  36 //
  37 class AnalysisUsage {
  38 public:
  39   typedef SmallVector<AnalysisID, 32> VectorType;
  40
  41 private:
  42   // Sets of analyses required and preserved by a pass
  43   VectorType Required, RequiredTransitive, Preserved;
  44   bool PreservesAll;
  45
  46 public:
  47   AnalysisUsage() : PreservesAll(false) {}
  48
  49   // addRequired - Add the specified ID to the required set of the usage info
  50   // for a pass.
  51   //
  52   AnalysisUsage &addRequiredID(AnalysisID ID);
  53   template<class PassClass>
  54   AnalysisUsage &addRequired() {
  55     return addRequiredID(Pass::getClassPassInfo<PassClass>());
  56   }
  57
  58   AnalysisUsage &addRequiredTransitiveID(AnalysisID ID);
  59   template<class PassClass>
  60   AnalysisUsage &addRequiredTransitive() {
  61     AnalysisID ID = Pass::getClassPassInfo<PassClass>();
  62     return addRequiredTransitiveID(ID);
  63   }
  64
  65   // addPreserved - Add the specified ID to the set of analyses preserved by
  66   // this pass
  67   //
  68   AnalysisUsage &addPreservedID(AnalysisID ID) {
  69     Preserved.push_back(ID);
  70     return *this;
  71   }
  72
  73   // addPreserved - Add the specified Pass class to the set of analyses
  74   // preserved by this pass.
  75   //
  76   template<class PassClass>
  77   AnalysisUsage &addPreserved() {
  78     assert(Pass::getClassPassInfo<PassClass>() && "Pass class not registered!");
  79     Preserved.push_back(Pass::getClassPassInfo<PassClass>());
  80     return *this;
  81   }
  82
  83   // addPreserved - Add the Pass with the specified argument string to the set
  84   // of analyses preserved by this pass. If no such Pass exists, do nothing.
  85   // This can be useful when a pass is trivially preserved, but may not be
  86   // linked in. Be careful about spelling!
  87   //
  88   AnalysisUsage &addPreserved(StringRef Arg) {
  89     const PassInfo *PI = Pass::lookupPassInfo(Arg);
  90     // If the pass exists, preserve it. Otherwise silently do nothing.
  91     if (PI) Preserved.push_back(PI);
  92     return *this;
  93   }
  94
  95   // setPreservesAll - Set by analyses that do not transform their input at all
  96   void setPreservesAll() { PreservesAll = true; }
  97   bool getPreservesAll() const { return PreservesAll; }
  98
  99   /// setPreservesCFG - This function should be called by the pass, iff they do
 100   /// not:
 101   ///
 102   ///  1. Add or remove basic blocks from the function
 103   ///  2. Modify terminator instructions in any way.
 104   ///
 105   /// This function annotates the AnalysisUsage info object to say that analyses
 106   /// that only depend on the CFG are preserved by this pass.
 107   ///
 108   void setPreservesCFG();
 109
 110   const VectorType &getRequiredSet() const { return Required; }
 111   const VectorType &getRequiredTransitiveSet() const {
 112     return RequiredTransitive;
 113   }
 114   const VectorType &getPreservedSet() const { return Preserved; }
 115 };
 116
 117 //===----------------------------------------------------------------------===//
 118 // AnalysisResolver - Simple interface used by Pass objects to pull all
 119 // analysis information out of pass manager that is responsible to manage
 120 // the pass.
 121 //
 122 class PMDataManager;
 123 class AnalysisResolver {
 124 private:
 125   AnalysisResolver();  // DO NOT IMPLEMENT
 126
 127 public:
 128   explicit AnalysisResolver(PMDataManager &P) : PM(P) { }
 129
 130   inline PMDataManager &getPMDataManager() { return PM; }
 131
 132   // Find pass that is implementing PI.
 133   Pass *findImplPass(const PassInfo *PI) {
 134     Pass *ResultPass = 0;
 135     for (unsigned i = 0; i < AnalysisImpls.size() ; ++i) {
 136       if (AnalysisImpls[i].first == PI) {
 137         ResultPass = AnalysisImpls[i].second;
 138         break;
 139       }
 140     }
 141     return ResultPass;
 142   }
 143
 144   // Find pass that is implementing PI. Initialize pass for Function F.
 145   Pass *findImplPass(Pass *P, const PassInfo *PI, Function &F);
 146
 147   void addAnalysisImplsPair(const PassInfo *PI, Pass *P) {
 148     std::pair<const PassInfo*, Pass*> pir = std::make_pair(PI,P);
 149     AnalysisImpls.push_back(pir);
 150   }
 151
 152   /// clearAnalysisImpls - Clear cache that is used to connect a pass to the
 153   /// the analysis (PassInfo).
 154   void clearAnalysisImpls() {
 155     AnalysisImpls.clear();
 156   }
 157
 158   // getAnalysisIfAvailable - Return analysis result or null if it doesn't exist
 159   Pass *getAnalysisIfAvailable(AnalysisID ID, bool Direction) const;
 160
 161   // AnalysisImpls - This keeps track of which passes implements the interfaces
 162   // that are required by the current pass (to implement getAnalysis()).
 163   std::vector<std::pair<const PassInfo*, Pass*> > AnalysisImpls;
 164
 165 private:
 166   // PassManager that is used to resolve analysis info
 167   PMDataManager &PM;
 168 };
 169
 170 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
 171 /// get analysis information that might be around, for example to update it.
 172 /// This is different than getAnalysis in that it can fail (if the analysis
 173 /// results haven't been computed), so should only be used if you can handle
 174 /// the case when the analysis is not available.  This method is often used by
 175 /// transformation APIs to update analysis results for a pass automatically as
 176 /// the transform is performed.
 177 ///
 178 template<typename AnalysisType>
 179 AnalysisType *Pass::getAnalysisIfAvailable() const {
 180   assert(Resolver && "Pass not resident in a PassManager object!");
 181
 182   const PassInfo *PI = getClassPassInfo<AnalysisType>();
 183   if (PI == 0) return 0;
 184
 185   Pass *ResultPass = Resolver->getAnalysisIfAvailable(PI, true);
 186   if (ResultPass == 0) return 0;
 187
 188   // Because the AnalysisType may not be a subclass of pass (for
 189   // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
 190   // adjust the return pointer (because the class may multiply inherit, once
 191   // from pass, once from AnalysisType).
 192   return (AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
 193 }
 194
 195 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
 196 /// to the analysis information that they claim to use by overriding the
 197 /// getAnalysisUsage function.
 198 ///
 199 template<typename AnalysisType>
 200 AnalysisType &Pass::getAnalysis() const {
 201   assert(Resolver && "Pass has not been inserted into a PassManager object!");
 202   return getAnalysisID<AnalysisType>(getClassPassInfo<AnalysisType>());
 203 }
 204
 205 template<typename AnalysisType>
 206 AnalysisType &Pass::getAnalysisID(const PassInfo *PI) const {
 207   assert(PI && "getAnalysis for unregistered pass!");
 208   assert(Resolver&&"Pass has not been inserted into a PassManager object!");
 209   // PI *must* appear in AnalysisImpls.  Because the number of passes used
 210   // should be a small number, we just do a linear search over a (dense)
 211   // vector.
 212   Pass *ResultPass = Resolver->findImplPass(PI);
 213   assert (ResultPass &&
 214           "getAnalysis*() called on an analysis that was not "
 215           "'required' by pass!");
 216
 217   // Because the AnalysisType may not be a subclass of pass (for
 218   // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
 219   // adjust the return pointer (because the class may multiply inherit, once
 220   // from pass, once from AnalysisType).
 221   return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
 222 }
 223
 224 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
 225 /// to the analysis information that they claim to use by overriding the
 226 /// getAnalysisUsage function.
 227 ///
 228 template<typename AnalysisType>
 229 AnalysisType &Pass::getAnalysis(Function &F) {
 230   assert(Resolver &&"Pass has not been inserted into a PassManager object!");
 231
 232   return getAnalysisID<AnalysisType>(getClassPassInfo<AnalysisType>(), F);
 233 }
 234
 235 template<typename AnalysisType>
 236 AnalysisType &Pass::getAnalysisID(const PassInfo *PI, Function &F) {
 237   assert(PI && "getAnalysis for unregistered pass!");
 238   assert(Resolver && "Pass has not been inserted into a PassManager object!");
 239   // PI *must* appear in AnalysisImpls.  Because the number of passes used
 240   // should be a small number, we just do a linear search over a (dense)
 241   // vector.
 242   Pass *ResultPass = Resolver->findImplPass(this, PI, F);
 243   assert(ResultPass && "Unable to find requested analysis info");
 244
 245   // Because the AnalysisType may not be a subclass of pass (for
 246   // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
 247   // adjust the return pointer (because the class may multiply inherit, once
 248   // from pass, once from AnalysisType).
 249   return *(AnalysisType*)ResultPass->getAdjustedAnalysisPointer(PI);
 250 }
 251
 252 } // End llvm namespace
 253
 254 #endif