lib/Analysis/MemDepPrinter.cpp

   1 //===- MemDepPrinter.cpp - Printer for MemoryDependenceAnalysis -----------===//
   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 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/ADT/SetVector.h"
  14 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
  15 #include "llvm/Analysis/Passes.h"
  16 #include "llvm/IR/CallSite.h"
  17 #include "llvm/IR/InstIterator.h"
  18 #include "llvm/IR/LLVMContext.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 using namespace llvm;
  22
  23 namespace {
  24   struct MemDepPrinter : public FunctionPass {
  25     const Function *F;
  26
  27     enum DepType {
  28       Clobber = 0,
  29       Def,
  30       NonFuncLocal,
  31       Unknown
  32     };
  33
  34     static const char *const DepTypeStr[];
  35
  36     typedef PointerIntPair<const Instruction *, 2, DepType> InstTypePair;
  37     typedef std::pair<InstTypePair, const BasicBlock *> Dep;
  38     typedef SmallSetVector<Dep, 4> DepSet;
  39     typedef DenseMap<const Instruction *, DepSet> DepSetMap;
  40     DepSetMap Deps;
  41
  42     static char ID; // Pass identifcation, replacement for typeid
  43     MemDepPrinter() : FunctionPass(ID) {
  44       initializeMemDepPrinterPass(*PassRegistry::getPassRegistry());
  45     }
  46
  47     bool runOnFunction(Function &F) override;
  48
  49     void print(raw_ostream &OS, const Module * = nullptr) const override;
  50
  51     void getAnalysisUsage(AnalysisUsage &AU) const override {
  52       AU.addRequiredTransitive<AAResultsWrapperPass>();
  53       AU.addRequiredTransitive<MemoryDependenceWrapperPass>();
  54       AU.setPreservesAll();
  55     }
  56
  57     void releaseMemory() override {
  58       Deps.clear();
  59       F = nullptr;
  60     }
  61
  62   private:
  63     static InstTypePair getInstTypePair(MemDepResult dep) {
  64       if (dep.isClobber())
  65         return InstTypePair(dep.getInst(), Clobber);
  66       if (dep.isDef())
  67         return InstTypePair(dep.getInst(), Def);
  68       if (dep.isNonFuncLocal())
  69         return InstTypePair(dep.getInst(), NonFuncLocal);
  70       assert(dep.isUnknown() && "unexpected dependence type");
  71       return InstTypePair(dep.getInst(), Unknown);
  72     }
  73     static InstTypePair getInstTypePair(const Instruction* inst, DepType type) {
  74       return InstTypePair(inst, type);
  75     }
  76   };
  77 }
  78
  79 char MemDepPrinter::ID = 0;
  80 INITIALIZE_PASS_BEGIN(MemDepPrinter, "print-memdeps",
  81                       "Print MemDeps of function", false, true)
  82 INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
  83 INITIALIZE_PASS_END(MemDepPrinter, "print-memdeps",
  84                       "Print MemDeps of function", false, true)
  85
  86 FunctionPass *llvm::createMemDepPrinter() {
  87   return new MemDepPrinter();
  88 }
  89
  90 const char *const MemDepPrinter::DepTypeStr[]
  91   = {"Clobber", "Def", "NonFuncLocal", "Unknown"};
  92
  93 bool MemDepPrinter::runOnFunction(Function &F) {
  94   this->F = &F;
  95   MemoryDependenceResults &MDA = getAnalysis<MemoryDependenceWrapperPass>().getMemDep();
  96
  97   // All this code uses non-const interfaces because MemDep is not
  98   // const-friendly, though nothing is actually modified.
  99   for (auto &I : instructions(F)) {
 100     Instruction *Inst = &I;
 101
 102     if (!Inst->mayReadFromMemory() && !Inst->mayWriteToMemory())
 103       continue;
 104
 105     MemDepResult Res = MDA.getDependency(Inst);
 106     if (!Res.isNonLocal()) {
 107       Deps[Inst].insert(std::make_pair(getInstTypePair(Res),
 108                                        static_cast<BasicBlock *>(nullptr)));
 109     } else if (auto CS = CallSite(Inst)) {
 110       const MemoryDependenceResults::NonLocalDepInfo &NLDI =
 111         MDA.getNonLocalCallDependency(CS);
 112
 113       DepSet &InstDeps = Deps[Inst];
 114       for (const NonLocalDepEntry &I : NLDI) {
 115         const MemDepResult &Res = I.getResult();
 116         InstDeps.insert(std::make_pair(getInstTypePair(Res), I.getBB()));
 117       }
 118     } else {
 119       SmallVector<NonLocalDepResult, 4> NLDI;
 120       assert( (isa<LoadInst>(Inst) || isa<StoreInst>(Inst) ||
 121                isa<VAArgInst>(Inst)) && "Unknown memory instruction!");
 122       MDA.getNonLocalPointerDependency(Inst, NLDI);
 123
 124       DepSet &InstDeps = Deps[Inst];
 125       for (const NonLocalDepResult &I : NLDI) {
 126         const MemDepResult &Res = I.getResult();
 127         InstDeps.insert(std::make_pair(getInstTypePair(Res), I.getBB()));
 128       }
 129     }
 130   }
 131
 132   return false;
 133 }
 134
 135 void MemDepPrinter::print(raw_ostream &OS, const Module *M) const {
 136   for (const auto &I : instructions(*F)) {
 137     const Instruction *Inst = &I;
 138
 139     DepSetMap::const_iterator DI = Deps.find(Inst);
 140     if (DI == Deps.end())
 141       continue;
 142
 143     const DepSet &InstDeps = DI->second;
 144
 145     for (const auto &I : InstDeps) {
 146       const Instruction *DepInst = I.first.getPointer();
 147       DepType type = I.first.getInt();
 148       const BasicBlock *DepBB = I.second;
 149
 150       OS << "    ";
 151       OS << DepTypeStr[type];
 152       if (DepBB) {
 153         OS << " in block ";
 154         DepBB->printAsOperand(OS, /*PrintType=*/false, M);
 155       }
 156       if (DepInst) {
 157         OS << " from: ";
 158         DepInst->print(OS);
 159       }
 160       OS << "\n";
 161     }
 162
 163     Inst->print(OS);
 164     OS << "\n\n";
 165   }
 166 }