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
MemDepPrinter__anon5f6848d80111::MemDepPrinter45 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
getAnalysisUsage__anon5f6848d80111::MemDepPrinter53 void getAnalysisUsage(AnalysisUsage &AU) const override {
54 AU.addRequiredTransitive<AAResultsWrapperPass>();
55 AU.addRequiredTransitive<MemoryDependenceWrapperPass>();
56 AU.setPreservesAll();
57 }
58
releaseMemory__anon5f6848d80111::MemDepPrinter59 void releaseMemory() override {
60 Deps.clear();
61 F = nullptr;
62 }
63
64 private:
getInstTypePair__anon5f6848d80111::MemDepPrinter65 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)
INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)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
runOnFunction(Function & F)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
print(raw_ostream & OS,const Module * M) const134 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 }
166