/// Look through a chain of LocationContexts to either find the
/// StackFrameContext that matches a DeclContext, or find a VarRegion
/// for a variable captured by a block.
static llvm::PointerUnion<const StackFrameContext *, const VarRegion *>
getStackOrCaptureRegionForDeclContext(const LocationContext *LC,
const DeclContext *DC,
const VarDecl *VD) {
while (LC) {
if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC)) {
if (cast<DeclContext>(SFC->getDecl()) == DC)
return SFC;
}
if (const BlockInvocationContext *BC =
dyn_cast<BlockInvocationContext>(LC)) {
const BlockDataRegion *BR =
static_cast<const BlockDataRegion*>(BC->getContextData());
// FIXME: This can be made more efficient.
for (BlockDataRegion::referenced_vars_iterator
I = BR->referenced_vars_begin(),
E = BR->referenced_vars_end(); I != E; ++I) {
if (const VarRegion *VR = dyn_cast<VarRegion>(I.getOriginalRegion()))
if (VR->getDecl() == VD)
return cast<VarRegion>(I.getCapturedRegion());
}
}
LC = LC->getParent();
}
return (const StackFrameContext*)0;
}
void BlockDataRegion::dumpToStream(raw_ostream &os) const {
os << "block_data{" << BC;
os << "; ";
for (BlockDataRegion::referenced_vars_iterator
I = referenced_vars_begin(),
E = referenced_vars_end(); I != E; ++I)
os << "(" << I.getCapturedRegion() << "," <<
I.getOriginalRegion() << ") ";
os << '}';
}
SmallVector<const MemRegion *, 4>
StackAddrEscapeChecker::getCapturedStackRegions(const BlockDataRegion &B,
CheckerContext &C) {
SmallVector<const MemRegion *, 4> Regions;
BlockDataRegion::referenced_vars_iterator I = B.referenced_vars_begin();
BlockDataRegion::referenced_vars_iterator E = B.referenced_vars_end();
for (; I != E; ++I) {
SVal Val = C.getState()->getSVal(I.getCapturedRegion());
const MemRegion *Region = Val.getAsRegion();
if (Region && isa<StackSpaceRegion>(Region->getMemorySpace()))
Regions.push_back(Region);
}
return Regions;
}
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.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 (Optional<UndefinedVal> V =
state->getSVal(I.getOriginalRegion()).getAs<UndefinedVal>()) {
if (ExplodedNode *N = C.generateSink()) {
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";
BugReport *R = new BugReport(*BT, os.str(), N);
if (const Expr *Ex = FindBlockDeclRefExpr(BE->getBody(), VD))
R->addRange(Ex->getSourceRange());
R->addVisitor(llvm::make_unique<FindLastStoreBRVisitor>(
*V, VR, /*EnableNullFPSuppression*/ false));
R->disablePathPruning();
// need location of block
C.emitReport(R);
}
}
}
}
bool ScanReachableSymbols::scan(const MemRegion *R) {
if (isa<MemSpaceRegion>(R))
return true;
unsigned &isVisited = visited[R];
if (isVisited)
return true;
isVisited = 1;
if (!visitor.VisitMemRegion(R))
return false;
// If this is a symbolic region, visit the symbol for the region.
if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
if (!visitor.VisitSymbol(SR->getSymbol()))
return false;
// If this is a subregion, also visit the parent regions.
if (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
const MemRegion *Super = SR->getSuperRegion();
if (!scan(Super))
return false;
// When we reach the topmost region, scan all symbols in it.
if (isa<MemSpaceRegion>(Super)) {
StoreManager &StoreMgr = state->getStateManager().getStoreManager();
if (!StoreMgr.scanReachableSymbols(state->getStore(), SR, *this))
return false;
}
}
// Regions captured by a block are also implicitly reachable.
if (const BlockDataRegion *BDR = dyn_cast<BlockDataRegion>(R)) {
BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
E = BDR->referenced_vars_end();
for ( ; I != E; ++I) {
if (!scan(I.getCapturedRegion()))
return false;
}
}
return true;
}
bool ScanReachableSymbols::scan(const MemRegion *R) {
if (isa<MemSpaceRegion>(R))
return true;
unsigned &isVisited = visited[R];
if (isVisited)
return true;
isVisited = 1;
if (!visitor.VisitMemRegion(R))
return false;
// If this is a symbolic region, visit the symbol for the region.
if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
if (!visitor.VisitSymbol(SR->getSymbol()))
return false;
// If this is a subregion, also visit the parent regions.
if (const SubRegion *SR = dyn_cast<SubRegion>(R))
if (!scan(SR->getSuperRegion()))
return false;
// Regions captured by a block are also implicitly reachable.
if (const BlockDataRegion *BDR = dyn_cast<BlockDataRegion>(R)) {
BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
E = BDR->referenced_vars_end();
for ( ; I != E; ++I) {
if (!scan(I.getCapturedRegion()))
return false;
}
}
// Now look at the binding to this region (if any).
if (!scan(state->getSValAsScalarOrLoc(R)))
return false;
// Now look at the subregions.
if (!SRM.get())
SRM.reset(state->getStateManager().getStoreManager().
getSubRegionMap(state->getStore()));
return SRM->iterSubRegions(R, *this);
}
void ExprEngine::VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
CanQualType T = getContext().getCanonicalType(BE->getType());
// Get the value of the block itself.
SVal V = svalBuilder.getBlockPointer(BE->getBlockDecl(), T,
Pred->getLocationContext(),
currBldrCtx->blockCount());
ProgramStateRef State = Pred->getState();
// If we created a new MemRegion for the block, we should explicitly bind
// the captured variables.
if (const BlockDataRegion *BDR =
dyn_cast_or_null<BlockDataRegion>(V.getAsRegion())) {
BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
E = BDR->referenced_vars_end();
for (; I != E; ++I) {
const MemRegion *capturedR = I.getCapturedRegion();
const MemRegion *originalR = I.getOriginalRegion();
if (capturedR != originalR) {
SVal originalV = State->getSVal(loc::MemRegionVal(originalR));
State = State->bindLoc(loc::MemRegionVal(capturedR), originalV);
}
}
}
ExplodedNodeSet Tmp;
StmtNodeBuilder Bldr(Pred, Tmp, *currBldrCtx);
Bldr.generateNode(BE, Pred,
State->BindExpr(BE, Pred->getLocationContext(), V),
nullptr, ProgramPoint::PostLValueKind);
// FIXME: Move all post/pre visits to ::Visit().
getCheckerManager().runCheckersForPostStmt(Dst, Tmp, BE, *this);
}
void ExprEngine::VisitBlockExpr(const BlockExpr *BE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
CanQualType T = getContext().getCanonicalType(BE->getType());
const BlockDecl *BD = BE->getBlockDecl();
// Get the value of the block itself.
SVal V = svalBuilder.getBlockPointer(BD, T,
Pred->getLocationContext(),
currBldrCtx->blockCount());
ProgramStateRef State = Pred->getState();
// If we created a new MemRegion for the block, we should explicitly bind
// the captured variables.
if (const BlockDataRegion *BDR =
dyn_cast_or_null<BlockDataRegion>(V.getAsRegion())) {
BlockDataRegion::referenced_vars_iterator I = BDR->referenced_vars_begin(),
E = BDR->referenced_vars_end();
auto CI = BD->capture_begin();
auto CE = BD->capture_end();
for (; I != E; ++I) {
const VarRegion *capturedR = I.getCapturedRegion();
const VarRegion *originalR = I.getOriginalRegion();
// If the capture had a copy expression, use the result of evaluating
// that expression, otherwise use the original value.
// We rely on the invariant that the block declaration's capture variables
// are a prefix of the BlockDataRegion's referenced vars (which may include
// referenced globals, etc.) to enable fast lookup of the capture for a
// given referenced var.
const Expr *copyExpr = nullptr;
if (CI != CE) {
assert(CI->getVariable() == capturedR->getDecl());
copyExpr = CI->getCopyExpr();
CI++;
}
if (capturedR != originalR) {
SVal originalV;
const LocationContext *LCtx = Pred->getLocationContext();
if (copyExpr) {
originalV = State->getSVal(copyExpr, LCtx);
} else {
originalV = State->getSVal(loc::MemRegionVal(originalR));
}
State = State->bindLoc(loc::MemRegionVal(capturedR), originalV, LCtx);
}
}
}
ExplodedNodeSet Tmp;
StmtNodeBuilder Bldr(Pred, Tmp, *currBldrCtx);
Bldr.generateNode(BE, Pred,
State->BindExpr(BE, Pred->getLocationContext(), V),
nullptr, ProgramPoint::PostLValueKind);
// FIXME: Move all post/pre visits to ::Visit().
getCheckerManager().runCheckersForPostStmt(Dst, Tmp, BE, *this);
}
