lib/Analysis/MemDepPrinter.cpp

   1 //===- MemDepPrinter.cpp - Printer for MemoryDependenceAnalysis -----------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //
  10 //===----------------------------------------------------------------------===//
  11
  12 #include "llvm/ADT/SetVector.h"
  13 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
  14 #include "llvm/Analysis/Passes.h"
  15 #include "llvm/IR/InstIterator.h"
  16 #include "llvm/IR/LLVMContext.h"
  17 #include "llvm/Support/ErrorHandling.h"
  18 #include "llvm/Support/raw_ostream.h"
  19 using namespace llvm;
  20
  21 namespace {
  22   struct MemDepPrinter : public FunctionPass {
  23     const Function *F;
  24
  25     enum DepType {
  26       Clobber = 0,
  27       Def,
  28       NonFuncLocal,
  29       Unknown
  30     };
  31
  32     static const char *const DepTypeStr[];
  33
  34     typedef PointerIntPair<const Instruction *, 2, DepType> InstTypePair;
  35     typedef std::pair<InstTypePair, const BasicBlock *> Dep;
  36     typedef SmallSetVector<Dep, 4> DepSet;
  37     typedef DenseMap<const Instruction *, DepSet> DepSetMap;
  38     DepSetMap Deps;
  39
  40     static char ID; // Pass identifcation, replacement for typeid
  41     MemDepPrinter() : FunctionPass(ID) {
  42       initializeMemDepPrinterPass(*PassRegistry::getPassRegistry());
  43     }
  44
  45     bool runOnFunction(Function &F) override;
  46
  47     void print(raw_ostream &OS, const Module * = nullptr) const override;
  48
  49     void getAnalysisUsage(AnalysisUsage &AU) const override {
  50       AU.addRequiredTransitive<AAResultsWrapperPass>();
  51       AU.addRequiredTransitive<MemoryDependenceWrapperPass>();
  52       AU.setPreservesAll();
  53     }
  54
  55     void releaseMemory() override {
  56       Deps.clear();
  57       F = nullptr;
  58     }
  59
  60   private:
  61     static InstTypePair getInstTypePair(MemDepResult dep) {
  62       if (dep.isClobber())
  63         return InstTypePair(dep.getInst(), Clobber);
  64       if (dep.isDef())
  65         return InstTypePair(dep.getInst(), Def);
  66       if (dep.isNonFuncLocal())
  67         return InstTypePair(dep.getInst(), NonFuncLocal);
  68       assert(dep.isUnknown() && "unexpected dependence type");
  69       return InstTypePair(dep.getInst(), Unknown);
  70     }
  71     static InstTypePair getInstTypePair(const Instruction* inst, DepType type) {
  72       return InstTypePair(inst, type);
  73     }
  74   };
  75 }
  76
  77 char MemDepPrinter::ID = 0;
  78 INITIALIZE_PASS_BEGIN(MemDepPrinter, "print-memdeps",
  79                       "Print MemDeps of function", false, true)
  80 INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
  81 INITIALIZE_PASS_END(MemDepPrinter, "print-memdeps",
  82                       "Print MemDeps of function", false, true)
  83
  84 FunctionPass *llvm::createMemDepPrinter() {
  85   return new MemDepPrinter();
  86 }
  87
  88 const char *const MemDepPrinter::DepTypeStr[]
  89   = {"Clobber", "Def", "NonFuncLocal", "Unknown"};
  90
  91 bool MemDepPrinter::runOnFunction(Function &F) {
  92   this->F = &F;
  93   MemoryDependenceResults &MDA = getAnalysis<MemoryDependenceWrapperPass>().getMemDep();
  94
  95   // All this code uses non-const interfaces because MemDep is not
  96   // const-friendly, though nothing is actually modified.
  97   for (auto &I : instructions(F)) {
  98     Instruction *Inst = &I;
  99
 100     if (!Inst->mayReadFromMemory() && !Inst->mayWriteToMemory())
 101       continue;
 102
 103     MemDepResult Res = MDA.getDependency(Inst);
 104     if (!Res.isNonLocal()) {
 105       Deps[Inst].insert(std::make_pair(getInstTypePair(Res),
 106                                        static_cast<BasicBlock *>(nullptr)));
 107     } else if (auto *Call = dyn_cast<CallBase>(Inst)) {
 108       const MemoryDependenceResults::NonLocalDepInfo &NLDI =
 109           MDA.getNonLocalCallDependency(Call);
 110
 111       DepSet &InstDeps = Deps[Inst];
 112       for (const NonLocalDepEntry &I : NLDI) {
 113         const MemDepResult &Res = I.getResult();
 114         InstDeps.insert(std::make_pair(getInstTypePair(Res), I.getBB()));
 115       }
 116     } else {
 117       SmallVector<NonLocalDepResult, 4> NLDI;
 118       assert( (isa<LoadInst>(Inst) || isa<StoreInst>(Inst) ||
 119                isa<VAArgInst>(Inst)) && "Unknown memory instruction!");
 120       MDA.getNonLocalPointerDependency(Inst, NLDI);
 121
 122       DepSet &InstDeps = Deps[Inst];
 123       for (const NonLocalDepResult &I : NLDI) {
 124         const MemDepResult &Res = I.getResult();
 125         InstDeps.insert(std::make_pair(getInstTypePair(Res), I.getBB()));
 126       }
 127     }
 128   }
 129
 130   return false;
 131 }
 132
 133 void MemDepPrinter::print(raw_ostream &OS, const Module *M) const {
 134   for (const auto &I : instructions(*F)) {
 135     const Instruction *Inst = &I;
 136
 137     DepSetMap::const_iterator DI = Deps.find(Inst);
 138     if (DI == Deps.end())
 139       continue;
 140
 141     const DepSet &InstDeps = DI->second;
 142
 143     for (const auto &I : InstDeps) {
 144       const Instruction *DepInst = I.first.getPointer();
 145       DepType type = I.first.getInt();
 146       const BasicBlock *DepBB = I.second;
 147
 148       OS << "    ";
 149       OS << DepTypeStr[type];
 150       if (DepBB) {
 151         OS << " in block ";
 152         DepBB->printAsOperand(OS, /*PrintType=*/false, M);
 153       }
 154       if (DepInst) {
 155         OS << " from: ";
 156         DepInst->print(OS);
 157       }
 158       OS << "\n";
 159     }
 160
 161     Inst->print(OS);
 162     OS << "\n\n";
 163   }
 164 }