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// UndefCapturedBlockVarChecker.cpp - Uninitialized captured vars -*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This checker detects blocks that capture uninitialized values.
//
//===----------------------------------------------------------------------===//
#include "ClangSACheckers.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 "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
namespace {
class UndefCapturedBlockVarChecker
: public Checker< check::PostStmt<BlockExpr> > {
mutable OwningPtr<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 (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end();
I!=E; ++I)
if (const Stmt *child = *I) {
const DeclRefExpr *BR = FindBlockDeclRefExpr(child, VD);
if (BR)
return BR;
}
return NULL;
}
void
UndefCapturedBlockVarChecker::checkPostStmt(const BlockExpr *BE,
CheckerContext &C) const {
if (!BE->getBlockDecl()->hasCaptures())
return;
ProgramStateRef state = C.getState();
const BlockDataRegion *R =
cast<BlockDataRegion>(state->getSVal(BE,
C.getLocationContext()).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;
const VarDecl *VD = VR->getDecl();
if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage())
continue;
// Get the VarRegion associated with VD in the local stack frame.
const LocationContext *LC = C.getLocationContext();
VR = C.getSValBuilder().getRegionManager().getVarRegion(VD, LC);
SVal VRVal = state->getSVal(VR);
if (VRVal.isUndef())
if (ExplodedNode *N = C.generateSink()) {
if (!BT)
BT.reset(new BuiltinBug("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";
BugReport *R = new BugReport(*BT, os.str(), N);
if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD))
R->addRange(Ex->getSourceRange());
R->addVisitor(new FindLastStoreBRVisitor(VRVal, VR));
// need location of block
C.EmitReport(R);
}
}
}
void ento::registerUndefCapturedBlockVarChecker(CheckerManager &mgr) {
mgr.registerChecker<UndefCapturedBlockVarChecker>();
}
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