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