1 //===--- UndefinedAssignmentChecker.h ---------------------------*- C++ -*--==//
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
7 //===----------------------------------------------------------------------===//
9 // This defines UndefinedAssignmentChecker, a builtin check in ExprEngine that
10 // checks for assigning undefined values.
12 //===----------------------------------------------------------------------===//
14 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
15 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
16 #include "clang/StaticAnalyzer/Core/Checker.h"
17 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
20 using namespace clang;
24 class UndefinedAssignmentChecker
25 : public Checker<check::Bind> {
26 mutable std::unique_ptr<BugType> BT;
29 void checkBind(SVal location, SVal val, const Stmt *S,
30 CheckerContext &C) const;
34 void UndefinedAssignmentChecker::checkBind(SVal location, SVal val,
36 CheckerContext &C) const {
40 // Do not report assignments of uninitialized values inside swap functions.
41 // This should allow to swap partially uninitialized structs
43 if (const FunctionDecl *EnclosingFunctionDecl =
44 dyn_cast<FunctionDecl>(C.getStackFrame()->getDecl()))
45 if (C.getCalleeName(EnclosingFunctionDecl) == "swap")
48 ExplodedNode *N = C.generateErrorNode();
53 static const char *const DefaultMsg =
54 "Assigned value is garbage or undefined";
56 BT.reset(new BuiltinBug(this, DefaultMsg));
58 // Generate a report for this bug.
59 llvm::SmallString<128> Str;
60 llvm::raw_svector_ostream OS(Str);
62 const Expr *ex = nullptr;
65 if (const UnaryOperator *U = dyn_cast<UnaryOperator>(StoreE)) {
66 OS << "The expression is an uninitialized value. "
67 "The computed value will also be garbage";
73 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(StoreE)) {
74 if (B->isCompoundAssignmentOp()) {
75 if (C.getSVal(B->getLHS()).isUndef()) {
76 OS << "The left expression of the compound assignment is an "
77 "uninitialized value. The computed value will also be garbage";
87 if (const DeclStmt *DS = dyn_cast<DeclStmt>(StoreE)) {
88 const VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
93 dyn_cast<CXXConstructorDecl>(C.getStackFrame()->getDecl())) {
94 if (CD->isImplicit()) {
95 for (auto I : CD->inits()) {
96 if (I->getInit()->IgnoreImpCasts() == StoreE) {
97 OS << "Value assigned to field '" << I->getMember()->getName()
98 << "' in implicit constructor is garbage or undefined";
108 if (OS.str().empty())
111 auto R = std::make_unique<PathSensitiveBugReport>(*BT, OS.str(), N);
113 R->addRange(ex->getSourceRange());
114 bugreporter::trackExpressionValue(N, ex, *R);
116 C.emitReport(std::move(R));
119 void ento::registerUndefinedAssignmentChecker(CheckerManager &mgr) {
120 mgr.registerChecker<UndefinedAssignmentChecker>();
123 bool ento::shouldRegisterUndefinedAssignmentChecker(const CheckerManager &mgr) {