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// UndefCapturedBlockVarChecker.cpp - Uninitialized captured vars -*- C++ -*-=//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This checker detects blocks that capture uninitialized values.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/AST/Attr.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/raw_ostream.h"
#include <optional>
using namespace clang;
using namespace ento;
namespace {
class UndefCapturedBlockVarChecker
: public Checker< check::PostStmt<BlockExpr> > {
mutable std::unique_ptr<BugType> BT;
public:
void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
};
} // end anonymous namespace
static const DeclRefExpr *FindBlockDeclRefExpr(const Stmt *S,
const VarDecl *VD) {
if (const DeclRefExpr *BR = dyn_cast<DeclRefExpr>(S))
if (BR->getDecl() == VD)
return BR;
for (const Stmt *Child : S->children())
if (Child)
if (const DeclRefExpr *BR = FindBlockDeclRefExpr(Child, VD))
return BR;
return nullptr;
}
void
UndefCapturedBlockVarChecker::checkPostStmt(const BlockExpr *BE,
CheckerContext &C) const {
if (!BE->getBlockDecl()->hasCaptures())
return;
ProgramStateRef state = C.getState();
auto *R = cast<BlockDataRegion>(C.getSVal(BE).getAsRegion());
BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
E = R->referenced_vars_end();
for (; I != E; ++I) {
// This VarRegion is the region associated with the block; we need
// the one associated with the encompassing context.
const VarRegion *VR = I.getCapturedRegion();
const VarDecl *VD = VR->getDecl();
if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage())
continue;
// Get the VarRegion associated with VD in the local stack frame.
if (std::optional<UndefinedVal> V =
state->getSVal(I.getOriginalRegion()).getAs<UndefinedVal>()) {
if (ExplodedNode *N = C.generateErrorNode()) {
if (!BT)
BT.reset(
new BuiltinBug(this, "uninitialized variable captured by block"));
// Generate a bug report.
SmallString<128> buf;
llvm::raw_svector_ostream os(buf);
os << "Variable '" << VD->getName()
<< "' is uninitialized when captured by block";
auto R = std::make_unique<PathSensitiveBugReport>(*BT, os.str(), N);
if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD))
R->addRange(Ex->getSourceRange());
bugreporter::trackStoredValue(*V, VR, *R,
{bugreporter::TrackingKind::Thorough,
/*EnableNullFPSuppression*/ false});
R->disablePathPruning();
// need location of block
C.emitReport(std::move(R));
}
}
}
}
void ento::registerUndefCapturedBlockVarChecker(CheckerManager &mgr) {
mgr.registerChecker<UndefCapturedBlockVarChecker>();
}
bool ento::shouldRegisterUndefCapturedBlockVarChecker(const CheckerManager &mgr) {
return true;
}
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