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"
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 }
167