llvm-project/clang-tools-extra/clang-tidy/bugprone/UncheckedOptionalAccessChec...

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//===--- UncheckedOptionalAccessCheck.cpp - clang-tidy --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "UncheckedOptionalAccessCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/FlowSensitive/ControlFlowContext.h"
#include "clang/Analysis/FlowSensitive/DataflowAnalysisContext.h"
#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
#include "clang/Analysis/FlowSensitive/DataflowLattice.h"
#include "clang/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.h"
#include "clang/Analysis/FlowSensitive/SourceLocationsLattice.h"
#include "clang/Analysis/FlowSensitive/WatchedLiteralsSolver.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/Any.h"
#include "llvm/ADT/Optional.h"
#include "llvm/Support/Error.h"
#include <memory>
#include <vector>
namespace clang {
namespace tidy {
namespace bugprone {
using ast_matchers::MatchFinder;
using dataflow::SourceLocationsLattice;
using dataflow::UncheckedOptionalAccessModel;
using llvm::Optional;
static constexpr llvm::StringLiteral FuncID("fun");
static Optional<SourceLocationsLattice>
analyzeFunction(const FunctionDecl &FuncDecl, ASTContext &ASTCtx) {
using dataflow::ControlFlowContext;
using dataflow::DataflowAnalysisState;
using llvm::Expected;
Expected<ControlFlowContext> Context =
ControlFlowContext::build(&FuncDecl, FuncDecl.getBody(), &ASTCtx);
if (!Context)
return llvm::None;
dataflow::DataflowAnalysisContext AnalysisContext(
std::make_unique<dataflow::WatchedLiteralsSolver>());
dataflow::Environment Env(AnalysisContext, FuncDecl);
UncheckedOptionalAccessModel Analysis(ASTCtx);
Expected<std::vector<Optional<DataflowAnalysisState<SourceLocationsLattice>>>>
BlockToOutputState =
dataflow::runDataflowAnalysis(*Context, Analysis, Env);
if (!BlockToOutputState)
return llvm::None;
assert(Context->getCFG().getExit().getBlockID() < BlockToOutputState->size());
const Optional<DataflowAnalysisState<SourceLocationsLattice>>
&ExitBlockState =
(*BlockToOutputState)[Context->getCFG().getExit().getBlockID()];
// `runDataflowAnalysis` doesn't guarantee that the exit block is visited;
// for example, when it is unreachable.
// FIXME: Diagnose violations even when the exit block is unreachable.
if (!ExitBlockState.hasValue())
return llvm::None;
return std::move(ExitBlockState->Lattice);
}
void UncheckedOptionalAccessCheck::registerMatchers(MatchFinder *Finder) {
using namespace ast_matchers;
auto HasOptionalCallDescendant = hasDescendant(callExpr(callee(cxxMethodDecl(
ofClass(UncheckedOptionalAccessModel::optionalClassDecl())))));
Finder->addMatcher(
decl(anyOf(functionDecl(unless(isExpansionInSystemHeader()),
// FIXME: Remove the filter below when lambdas are
// well supported by the check.
unless(hasDeclContext(cxxRecordDecl(isLambda()))),
hasBody(HasOptionalCallDescendant)),
cxxConstructorDecl(hasAnyConstructorInitializer(
withInitializer(HasOptionalCallDescendant)))))
.bind(FuncID),
this);
}
void UncheckedOptionalAccessCheck::check(
const MatchFinder::MatchResult &Result) {
if (Result.SourceManager->getDiagnostics().hasUncompilableErrorOccurred())
return;
const auto *FuncDecl = Result.Nodes.getNodeAs<FunctionDecl>(FuncID);
if (FuncDecl->isTemplated())
return;
if (Optional<SourceLocationsLattice> Errors =
analyzeFunction(*FuncDecl, *Result.Context))
for (const SourceLocation &Loc : Errors->getSourceLocations())
diag(Loc, "unchecked access to optional value");
}
} // namespace bugprone
} // namespace tidy
} // namespace clang