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/Analysis/Passes.h"
14#include "llvm/ADT/SetVector.h"
15#include "llvm/Analysis/MemoryDependenceAnalysis.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"
21using namespace llvm;
22
23namespace {
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<MemoryDependenceAnalysis>();
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
79char MemDepPrinter::ID = 0;
80INITIALIZE_PASS_BEGIN(MemDepPrinter, "print-memdeps",
81                      "Print MemDeps of function", false, true)
82INITIALIZE_PASS_DEPENDENCY(MemoryDependenceAnalysis)
83INITIALIZE_PASS_END(MemDepPrinter, "print-memdeps",
84                      "Print MemDeps of function", false, true)
85
86FunctionPass *llvm::createMemDepPrinter() {
87  return new MemDepPrinter();
88}
89
90const char *const MemDepPrinter::DepTypeStr[]
91  = {"Clobber", "Def", "NonFuncLocal", "Unknown"};
92
93bool MemDepPrinter::runOnFunction(Function &F) {
94  this->F = &F;
95  MemoryDependenceAnalysis &MDA = getAnalysis<MemoryDependenceAnalysis>();
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 MemoryDependenceAnalysis::NonLocalDepInfo &NLDI =
111        MDA.getNonLocalCallDependency(CS);
112
113      DepSet &InstDeps = Deps[Inst];
114      for (MemoryDependenceAnalysis::NonLocalDepInfo::const_iterator
115           I = NLDI.begin(), E = NLDI.end(); I != E; ++I) {
116        const MemDepResult &Res = I->getResult();
117        InstDeps.insert(std::make_pair(getInstTypePair(Res), I->getBB()));
118      }
119    } else {
120      SmallVector<NonLocalDepResult, 4> NLDI;
121      assert( (isa<LoadInst>(Inst) || isa<StoreInst>(Inst) ||
122               isa<VAArgInst>(Inst)) && "Unknown memory instruction!");
123      MDA.getNonLocalPointerDependency(Inst, NLDI);
124
125      DepSet &InstDeps = Deps[Inst];
126      for (SmallVectorImpl<NonLocalDepResult>::const_iterator
127           I = NLDI.begin(), E = NLDI.end(); I != E; ++I) {
128        const MemDepResult &Res = I->getResult();
129        InstDeps.insert(std::make_pair(getInstTypePair(Res), I->getBB()));
130      }
131    }
132  }
133
134  return false;
135}
136
137void MemDepPrinter::print(raw_ostream &OS, const Module *M) const {
138  for (const auto &I : instructions(*F)) {
139    const Instruction *Inst = &I;
140
141    DepSetMap::const_iterator DI = Deps.find(Inst);
142    if (DI == Deps.end())
143      continue;
144
145    const DepSet &InstDeps = DI->second;
146
147    for (const auto &I : InstDeps) {
148      const Instruction *DepInst = I.first.getPointer();
149      DepType type = I.first.getInt();
150      const BasicBlock *DepBB = I.second;
151
152      OS << "    ";
153      OS << DepTypeStr[type];
154      if (DepBB) {
155        OS << " in block ";
156        DepBB->printAsOperand(OS, /*PrintType=*/false, M);
157      }
158      if (DepInst) {
159        OS << " from: ";
160        DepInst->print(OS);
161      }
162      OS << "\n";
163    }
164
165    Inst->print(OS);
166    OS << "\n\n";
167  }
168}
169