1//===-- MPIChecker.cpp - Checker Entry Point Class --------------*- C++ -*-===//
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/// \file
10/// This file defines the main class of MPI-Checker which serves as an entry
11/// point. It is created once for each translation unit analysed.
12/// The checker defines path-sensitive checks, to verify correct usage of the
13/// MPI API.
14///
15//===----------------------------------------------------------------------===//
16
17#include "MPIChecker.h"
18#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h"
20
21namespace clang {
22namespace ento {
23namespace mpi {
24
25void MPIChecker::checkDoubleNonblocking(const CallEvent &PreCallEvent,
26 CheckerContext &Ctx) const {
27 if (!FuncClassifier->isNonBlockingType(IdentInfo: PreCallEvent.getCalleeIdentifier())) {
28 return;
29 }
30 const MemRegion *const MR =
31 PreCallEvent.getArgSVal(Index: PreCallEvent.getNumArgs() - 1).getAsRegion();
32 if (!MR)
33 return;
34 const ElementRegion *const ER = dyn_cast<ElementRegion>(Val: MR);
35
36 // The region must be typed, in order to reason about it.
37 if (!isa<TypedRegion>(Val: MR) || (ER && !isa<TypedRegion>(Val: ER->getSuperRegion())))
38 return;
39
40 ProgramStateRef State = Ctx.getState();
41 const Request *const Req = State->get<RequestMap>(key: MR);
42
43 // double nonblocking detected
44 if (Req && Req->CurrentState == Request::State::Nonblocking) {
45 ExplodedNode *ErrorNode = Ctx.generateNonFatalErrorNode();
46 BReporter.reportDoubleNonblocking(MPICallEvent: PreCallEvent, Req: *Req, RequestRegion: MR, ExplNode: ErrorNode,
47 BReporter&: Ctx.getBugReporter());
48 Ctx.addTransition(State: ErrorNode->getState(), Pred: ErrorNode);
49 }
50 // no error
51 else {
52 State = State->set<RequestMap>(K: MR, E: Request::State::Nonblocking);
53 Ctx.addTransition(State);
54 }
55}
56
57void MPIChecker::checkUnmatchedWaits(const CallEvent &PreCallEvent,
58 CheckerContext &Ctx) const {
59 if (!FuncClassifier->isWaitType(IdentInfo: PreCallEvent.getCalleeIdentifier()))
60 return;
61 const MemRegion *const MR = topRegionUsedByWait(CE: PreCallEvent);
62 if (!MR)
63 return;
64 const ElementRegion *const ER = dyn_cast<ElementRegion>(Val: MR);
65
66 // The region must be typed, in order to reason about it.
67 if (!isa<TypedRegion>(Val: MR) || (ER && !isa<TypedRegion>(Val: ER->getSuperRegion())))
68 return;
69
70 llvm::SmallVector<const MemRegion *, 2> ReqRegions;
71 allRegionsUsedByWait(ReqRegions, MR, CE: PreCallEvent, Ctx);
72 if (ReqRegions.empty())
73 return;
74
75 ProgramStateRef State = Ctx.getState();
76 static CheckerProgramPointTag Tag("MPI-Checker", "UnmatchedWait");
77 ExplodedNode *ErrorNode{nullptr};
78
79 // Check all request regions used by the wait function.
80 for (const auto &ReqRegion : ReqRegions) {
81 const Request *const Req = State->get<RequestMap>(key: ReqRegion);
82 State = State->set<RequestMap>(K: ReqRegion, E: Request::State::Wait);
83 if (!Req) {
84 if (!ErrorNode) {
85 ErrorNode = Ctx.generateNonFatalErrorNode(State, Tag: &Tag);
86 State = ErrorNode->getState();
87 }
88 // A wait has no matching nonblocking call.
89 BReporter.reportUnmatchedWait(CE: PreCallEvent, RequestRegion: ReqRegion, ExplNode: ErrorNode,
90 BReporter&: Ctx.getBugReporter());
91 }
92 }
93
94 if (!ErrorNode) {
95 Ctx.addTransition(State);
96 } else {
97 Ctx.addTransition(State, Pred: ErrorNode);
98 }
99}
100
101void MPIChecker::checkMissingWaits(SymbolReaper &SymReaper,
102 CheckerContext &Ctx) const {
103 ProgramStateRef State = Ctx.getState();
104 const auto &Requests = State->get<RequestMap>();
105 if (Requests.isEmpty())
106 return;
107
108 static CheckerProgramPointTag Tag("MPI-Checker", "MissingWait");
109 ExplodedNode *ErrorNode{nullptr};
110
111 auto ReqMap = State->get<RequestMap>();
112 for (const auto &Req : ReqMap) {
113 if (!SymReaper.isLiveRegion(region: Req.first)) {
114 if (Req.second.CurrentState == Request::State::Nonblocking) {
115
116 if (!ErrorNode) {
117 ErrorNode = Ctx.generateNonFatalErrorNode(State, Tag: &Tag);
118 State = ErrorNode->getState();
119 }
120 BReporter.reportMissingWait(Req: Req.second, RequestRegion: Req.first, ExplNode: ErrorNode,
121 BReporter&: Ctx.getBugReporter());
122 }
123 State = State->remove<RequestMap>(K: Req.first);
124 }
125 }
126
127 // Transition to update the state regarding removed requests.
128 if (!ErrorNode) {
129 Ctx.addTransition(State);
130 } else {
131 Ctx.addTransition(State, Pred: ErrorNode);
132 }
133}
134
135const MemRegion *MPIChecker::topRegionUsedByWait(const CallEvent &CE) const {
136
137 if (FuncClassifier->isMPI_Wait(IdentInfo: CE.getCalleeIdentifier())) {
138 return CE.getArgSVal(Index: 0).getAsRegion();
139 } else if (FuncClassifier->isMPI_Waitall(IdentInfo: CE.getCalleeIdentifier())) {
140 return CE.getArgSVal(Index: 1).getAsRegion();
141 } else {
142 return (const MemRegion *)nullptr;
143 }
144}
145
146void MPIChecker::allRegionsUsedByWait(
147 llvm::SmallVector<const MemRegion *, 2> &ReqRegions,
148 const MemRegion *const MR, const CallEvent &CE, CheckerContext &Ctx) const {
149
150 MemRegionManager &RegionManager = MR->getMemRegionManager();
151
152 if (FuncClassifier->isMPI_Waitall(IdentInfo: CE.getCalleeIdentifier())) {
153 const SubRegion *SuperRegion{nullptr};
154 if (const ElementRegion *const ER = MR->getAs<ElementRegion>()) {
155 SuperRegion = cast<SubRegion>(Val: ER->getSuperRegion());
156 }
157
158 // A single request is passed to MPI_Waitall.
159 if (!SuperRegion) {
160 ReqRegions.push_back(Elt: MR);
161 return;
162 }
163
164 DefinedOrUnknownSVal ElementCount = getDynamicElementCount(
165 State: Ctx.getState(), MR: SuperRegion, SVB&: Ctx.getSValBuilder(),
166 Ty: CE.getArgExpr(Index: 1)->getType()->getPointeeType());
167 const llvm::APSInt &ArrSize =
168 ElementCount.castAs<nonloc::ConcreteInt>().getValue();
169
170 for (size_t i = 0; i < ArrSize; ++i) {
171 const NonLoc Idx = Ctx.getSValBuilder().makeArrayIndex(idx: i);
172
173 const ElementRegion *const ER = RegionManager.getElementRegion(
174 elementType: CE.getArgExpr(Index: 1)->getType()->getPointeeType(), Idx, superRegion: SuperRegion,
175 Ctx: Ctx.getASTContext());
176
177 ReqRegions.push_back(Elt: ER->getAs<MemRegion>());
178 }
179 } else if (FuncClassifier->isMPI_Wait(IdentInfo: CE.getCalleeIdentifier())) {
180 ReqRegions.push_back(Elt: MR);
181 }
182}
183
184} // end of namespace: mpi
185} // end of namespace: ento
186} // end of namespace: clang
187
188// Registers the checker for static analysis.
189void clang::ento::registerMPIChecker(CheckerManager &MGR) {
190 MGR.registerChecker<clang::ento::mpi::MPIChecker>();
191}
192
193bool clang::ento::shouldRegisterMPIChecker(const CheckerManager &mgr) {
194 return true;
195}
196