8138d85f63
A clang user pointed out that messages for the static analyzer undefined assignment checker use the term ‘garbage’, which might have a negative connotation to some users. This change updates the messages to use the term ‘uninitialized’. This is the usual reason why a value is undefined in the static analyzer and describes the logical error that a programmer should take action to fix. Out-of-bounds reads can also produce undefined values in the static analyzer. The right long-term design is to have to the array bounds checker cover out-of-bounds reads, so we do not cover that case in the updated messages. The recent improvements to the array bounds checker make it a candidate to add to the core set of checkers. rdar://133418644
119 lines
3.5 KiB
C++
119 lines
3.5 KiB
C++
//===--- UndefinedAssignmentChecker.h ---------------------------*- C++ -*--==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This defines UndefinedAssignmentChecker, a builtin check in ExprEngine that
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// checks for assigning undefined values.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
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#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
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#include "clang/StaticAnalyzer/Core/Checker.h"
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#include "clang/StaticAnalyzer/Core/CheckerManager.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
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using namespace clang;
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using namespace ento;
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namespace {
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class UndefinedAssignmentChecker
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: public Checker<check::Bind> {
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const BugType BT{this, "Assigned value is uninitialized"};
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public:
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void checkBind(SVal location, SVal val, const Stmt *S,
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CheckerContext &C) const;
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};
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}
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void UndefinedAssignmentChecker::checkBind(SVal location, SVal val,
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const Stmt *StoreE,
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CheckerContext &C) const {
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if (!val.isUndef())
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return;
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// Do not report assignments of uninitialized values inside swap functions.
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// This should allow to swap partially uninitialized structs
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if (const FunctionDecl *EnclosingFunctionDecl =
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dyn_cast<FunctionDecl>(C.getStackFrame()->getDecl()))
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if (C.getCalleeName(EnclosingFunctionDecl) == "swap")
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return;
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ExplodedNode *N = C.generateErrorNode();
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if (!N)
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return;
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// Generate a report for this bug.
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llvm::SmallString<128> Str;
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llvm::raw_svector_ostream OS(Str);
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const Expr *ex = nullptr;
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while (StoreE) {
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if (const UnaryOperator *U = dyn_cast<UnaryOperator>(StoreE)) {
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OS << "The expression uses uninitialized memory";
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ex = U->getSubExpr();
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break;
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}
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if (const BinaryOperator *B = dyn_cast<BinaryOperator>(StoreE)) {
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if (B->isCompoundAssignmentOp()) {
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if (C.getSVal(B->getLHS()).isUndef()) {
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OS << "The left expression of the compound assignment uses "
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<< "uninitialized memory";
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ex = B->getLHS();
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break;
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}
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}
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ex = B->getRHS();
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break;
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}
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if (const DeclStmt *DS = dyn_cast<DeclStmt>(StoreE)) {
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const VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
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ex = VD->getInit();
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}
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if (const auto *CD =
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dyn_cast<CXXConstructorDecl>(C.getStackFrame()->getDecl())) {
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if (CD->isImplicit()) {
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for (auto *I : CD->inits()) {
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if (I->getInit()->IgnoreImpCasts() == StoreE) {
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OS << "Value assigned to field '" << I->getMember()->getName()
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<< "' in implicit constructor is uninitialized";
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break;
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}
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}
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}
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}
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break;
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}
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if (OS.str().empty())
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OS << BT.getDescription();
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auto R = std::make_unique<PathSensitiveBugReport>(BT, OS.str(), N);
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if (ex) {
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R->addRange(ex->getSourceRange());
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bugreporter::trackExpressionValue(N, ex, *R);
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}
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C.emitReport(std::move(R));
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}
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void ento::registerUndefinedAssignmentChecker(CheckerManager &mgr) {
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mgr.registerChecker<UndefinedAssignmentChecker>();
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}
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bool ento::shouldRegisterUndefinedAssignmentChecker(const CheckerManager &mgr) {
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return true;
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}
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