reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143
  144
  145
  146
  147
  148
  149
  150
  151
  152
  153
  154
  155
  156
  157
  158
  159
  160
  161
  162
  163
  164
//===- MemDepPrinter.cpp - Printer for MemoryDependenceAnalysis -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/SetVector.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;

namespace {
  struct MemDepPrinter : public FunctionPass {
    const Function *F;

    enum DepType {
      Clobber = 0,
      Def,
      NonFuncLocal,
      Unknown
    };

    static const char *const DepTypeStr[];

    typedef PointerIntPair<const Instruction *, 2, DepType> InstTypePair;
    typedef std::pair<InstTypePair, const BasicBlock *> Dep;
    typedef SmallSetVector<Dep, 4> DepSet;
    typedef DenseMap<const Instruction *, DepSet> DepSetMap;
    DepSetMap Deps;

    static char ID; // Pass identifcation, replacement for typeid
    MemDepPrinter() : FunctionPass(ID) {
      initializeMemDepPrinterPass(*PassRegistry::getPassRegistry());
    }

    bool runOnFunction(Function &F) override;

    void print(raw_ostream &OS, const Module * = nullptr) const override;

    void getAnalysisUsage(AnalysisUsage &AU) const override {
      AU.addRequiredTransitive<AAResultsWrapperPass>();
      AU.addRequiredTransitive<MemoryDependenceWrapperPass>();
      AU.setPreservesAll();
    }

    void releaseMemory() override {
      Deps.clear();
      F = nullptr;
    }

  private:
    static InstTypePair getInstTypePair(MemDepResult dep) {
      if (dep.isClobber())
        return InstTypePair(dep.getInst(), Clobber);
      if (dep.isDef())
        return InstTypePair(dep.getInst(), Def);
      if (dep.isNonFuncLocal())
        return InstTypePair(dep.getInst(), NonFuncLocal);
      assert(dep.isUnknown() && "unexpected dependence type");
      return InstTypePair(dep.getInst(), Unknown);
    }
    static InstTypePair getInstTypePair(const Instruction* inst, DepType type) {
      return InstTypePair(inst, type);
    }
  };
}

char MemDepPrinter::ID = 0;
INITIALIZE_PASS_BEGIN(MemDepPrinter, "print-memdeps",
                      "Print MemDeps of function", false, true)
INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
INITIALIZE_PASS_END(MemDepPrinter, "print-memdeps",
                      "Print MemDeps of function", false, true)

FunctionPass *llvm::createMemDepPrinter() {
  return new MemDepPrinter();
}

const char *const MemDepPrinter::DepTypeStr[]
  = {"Clobber", "Def", "NonFuncLocal", "Unknown"};

bool MemDepPrinter::runOnFunction(Function &F) {
  this->F = &F;
  MemoryDependenceResults &MDA = getAnalysis<MemoryDependenceWrapperPass>().getMemDep();

  // All this code uses non-const interfaces because MemDep is not
  // const-friendly, though nothing is actually modified.
  for (auto &I : instructions(F)) {
    Instruction *Inst = &I;

    if (!Inst->mayReadFromMemory() && !Inst->mayWriteToMemory())
      continue;

    MemDepResult Res = MDA.getDependency(Inst);
    if (!Res.isNonLocal()) {
      Deps[Inst].insert(std::make_pair(getInstTypePair(Res),
                                       static_cast<BasicBlock *>(nullptr)));
    } else if (auto *Call = dyn_cast<CallBase>(Inst)) {
      const MemoryDependenceResults::NonLocalDepInfo &NLDI =
          MDA.getNonLocalCallDependency(Call);

      DepSet &InstDeps = Deps[Inst];
      for (const NonLocalDepEntry &I : NLDI) {
        const MemDepResult &Res = I.getResult();
        InstDeps.insert(std::make_pair(getInstTypePair(Res), I.getBB()));
      }
    } else {
      SmallVector<NonLocalDepResult, 4> NLDI;
      assert( (isa<LoadInst>(Inst) || isa<StoreInst>(Inst) ||
               isa<VAArgInst>(Inst)) && "Unknown memory instruction!");
      MDA.getNonLocalPointerDependency(Inst, NLDI);

      DepSet &InstDeps = Deps[Inst];
      for (const NonLocalDepResult &I : NLDI) {
        const MemDepResult &Res = I.getResult();
        InstDeps.insert(std::make_pair(getInstTypePair(Res), I.getBB()));
      }
    }
  }

  return false;
}

void MemDepPrinter::print(raw_ostream &OS, const Module *M) const {
  for (const auto &I : instructions(*F)) {
    const Instruction *Inst = &I;

    DepSetMap::const_iterator DI = Deps.find(Inst);
    if (DI == Deps.end())
      continue;

    const DepSet &InstDeps = DI->second;

    for (const auto &I : InstDeps) {
      const Instruction *DepInst = I.first.getPointer();
      DepType type = I.first.getInt();
      const BasicBlock *DepBB = I.second;

      OS << "    ";
      OS << DepTypeStr[type];
      if (DepBB) {
        OS << " in block ";
        DepBB->printAsOperand(OS, /*PrintType=*/false, M);
      }
      if (DepInst) {
        OS << " from: ";
        DepInst->print(OS);
      }
      OS << "\n";
    }

    Inst->print(OS);
    OS << "\n\n";
  }
}