Coverage Report

Created: 2020-09-19 12:23

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/StaticAnalyzer/Checkers/UndefCapturedBlockVarChecker.cpp
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// UndefCapturedBlockVarChecker.cpp - Uninitialized captured vars -*- 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 checker detects blocks that capture uninitialized 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/AST/Attr.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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#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/Support/raw_ostream.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 UndefCapturedBlockVarChecker
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  : public Checker< check::PostStmt<BlockExpr> > {
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  mutable std::unique_ptr<BugType> BT;
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public:
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  void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
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};
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} // end anonymous namespace
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static const DeclRefExpr *FindBlockDeclRefExpr(const Stmt *S,
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                                               const VarDecl *VD) {
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  if (const DeclRefExpr *BR = dyn_cast<DeclRefExpr>(S))
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    if (BR->getDecl() == VD)
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      return BR;
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  for (const Stmt *Child : S->children())
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    if (Child)
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      if (const DeclRefExpr *BR = FindBlockDeclRefExpr(Child, VD))
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        return BR;
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  return nullptr;
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}
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void
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UndefCapturedBlockVarChecker::checkPostStmt(const BlockExpr *BE,
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                                            CheckerContext &C) const {
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  if (!BE->getBlockDecl()->hasCaptures())
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    return;
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  ProgramStateRef state = C.getState();
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  auto *R = cast<BlockDataRegion>(C.getSVal(BE).getAsRegion());
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  BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
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                                            E = R->referenced_vars_end();
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  for (; I != E; 
++I284
) {
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    // This VarRegion is the region associated with the block; we need
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    // the one associated with the encompassing context.
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    const VarRegion *VR = I.getCapturedRegion();
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    const VarDecl *VD = VR->getDecl();
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    if (VD->hasAttr<BlocksAttr>() || 
!VD->hasLocalStorage()216
)
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      continue;
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    // Get the VarRegion associated with VD in the local stack frame.
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    if (Optional<UndefinedVal> V =
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          state->getSVal(I.getOriginalRegion()).getAs<UndefinedVal>()) {
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      if (ExplodedNode *N = C.generateErrorNode()) {
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        if (!BT)
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          BT.reset(
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              new BuiltinBug(this, "uninitialized variable captured by block"));
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        // Generate a bug report.
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        SmallString<128> buf;
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        llvm::raw_svector_ostream os(buf);
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        os << "Variable '" << VD->getName()
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           << "' is uninitialized when captured by block";
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        auto R = std::make_unique<PathSensitiveBugReport>(*BT, os.str(), N);
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        if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD))
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          R->addRange(Ex->getSourceRange());
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        R->addVisitor(std::make_unique<FindLastStoreBRVisitor>(
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            *V, VR, /*EnableNullFPSuppression*/ false,
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            bugreporter::TrackingKind::Thorough));
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        R->disablePathPruning();
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        // need location of block
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        C.emitReport(std::move(R));
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      }
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    }
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  }
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}
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void ento::registerUndefCapturedBlockVarChecker(CheckerManager &mgr) {
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  mgr.registerChecker<UndefCapturedBlockVarChecker>();
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}
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bool ento::shouldRegisterUndefCapturedBlockVarChecker(const CheckerManager &mgr) {
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  return true;
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}