================
@@ -0,0 +1,376 @@
+#include "clang/Analysis/Analyses/LifetimeSafety/LifetimeAnnotations.h"
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+
+REGISTER_SET_FACTORY_WITH_PROGRAMSTATE(LifetimeSourceSet, const MemRegion *)
+REGISTER_MAP_WITH_PROGRAMSTATE(LifetimeBoundMap, SymbolRef, LifetimeSourceSet)
+
+REGISTER_MAP_WITH_PROGRAMSTATE(LifetimeBoundMapVal, const MemRegion *,
+ LifetimeSourceSet)
+REGISTER_SET_WITH_PROGRAMSTATE(DeadSourceSet, const MemRegion *)
+
+namespace {
+class LifetimeAnnotations
+ : public Checker<check::PostCall, check::EndFunction, check::LifetimeEnd,
+ check::Location> {
+public:
+ void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
+ void printState(raw_ostream &Out, ProgramStateRef State, const char *NL,
+ const char *Sep) const override;
+ ProgramStateRef bindValues(ProgramStateRef State, SVal RetVal,
+ const MemRegion *Source) const;
+ bool hasDanglingSource(const MemRegion *Source, ProgramStateRef State,
+ CheckerContext &C) const;
+ void reportDanglingSource(const MemRegion *Region, ExplodedNode *N,
+ CheckerContext &C) const;
+ void reportUseAfterScope(const MemRegion *Region, ExplodedNode *N,
+ CheckerContext &C) const;
+
+ template <typename MapTy, typename KeyTy>
+ void checkReturnedBorrower(const MapTy &Map, const KeyTy RetKey,
+ ProgramStateRef State, CheckerContext &C) const;
+ void reportDanglingBorrower(const LifetimeSourceSet *Sources, CheckerContext
&C) const;
+ void checkEndFunction(const ReturnStmt *RS, CheckerContext &C) const;
+ void checkLifetimeEnd(const VarDecl *VD, CheckerContext &C) const;
+ void checkLocation(SVal Loc, bool IsLoad, const Stmt *S,
+ CheckerContext &C) const;
+ void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
+
+ const BugType BugMsg{this, "LifetimeAnnotations", "LifetimeBound"};
+};
+
+} // namespace
+
+ProgramStateRef LifetimeAnnotations::bindValues(ProgramStateRef State,
+ SVal RetVal,
+ const MemRegion *Source) const
{
+ LifetimeSourceSet::Factory &F =
+ State->getStateManager().get_context<LifetimeSourceSet>();
+
+ if (SymbolRef RetValSym = RetVal.getAsSymbol(/*IncludeBaseRegions=*/true)) {
+ const LifetimeSourceSet *LBSet = State->get<LifetimeBoundMap>(RetValSym);
+ LifetimeSourceSet Set = LBSet ? *LBSet : F.getEmptySet();
+ Set = F.add(Set, Source);
+ State = State->set<LifetimeBoundMap>(RetValSym, Set);
+ } else if (const MemRegion *RetValRegion = RetVal.getAsRegion()) {
+ const LifetimeSourceSet *LBValSet =
+ State->get<LifetimeBoundMapVal>(RetValRegion);
+ LifetimeSourceSet Set = LBValSet ? *LBValSet : F.getEmptySet();
+ Set = F.add(Set, Source);
+ State = State->set<LifetimeBoundMapVal>(RetValRegion, Set);
+ }
+ return State;
+}
+
+void LifetimeAnnotations::checkPostCall(const CallEvent &Call,
+ CheckerContext &C) const {
+ ProgramStateRef State = C.getState();
+
+ const auto *FC = dyn_cast<AnyFunctionCall>(&Call);
+ if (!FC)
+ return;
+
+ const FunctionDecl *FD = FC->getDecl();
+ if (!FD)
+ return;
+
+ SVal RetVal = Call.getReturnValue();
+
+ for (const ParmVarDecl *PVD : FD->parameters()) {
+ if (PVD->hasAttr<LifetimeBoundAttr>()) {
+ unsigned Idx = PVD->getFunctionScopeIndex();
+ SVal Arg = Call.getArgSVal(Idx);
+ if (const MemRegion *ArgValRegion = Arg.getAsRegion())
+ State = bindValues(State, RetVal, ArgValRegion);
+ }
+ }
+
+ if (const auto *IC = dyn_cast<CXXInstanceCall>(&Call)) {
+ if (lifetimes::implicitObjectParamIsLifetimeBound(FD)) {
+ if (const MemRegion *AttrRegion = IC->getCXXThisVal().getAsRegion()) {
+ State = bindValues(State, RetVal, AttrRegion);
+ }
+ }
+ }
+ C.addTransition(State);
+}
+
+bool LifetimeAnnotations::hasDanglingSource(const MemRegion *Source,
+ ProgramStateRef State,
+ CheckerContext &C) const {
+ // FIXME: Currently the checker only focuses on stack MemRegions only since
+ // that is the scope of week 3. Sources without a stack region are not
+ // covered, but should be implemented as well next step.
+ if (const auto *StackSpace =
+ Source->getMemorySpaceAs<StackSpaceRegion>(State)) {
+ const StackFrame *SF = StackSpace->getStackFrame();
+ const StackFrame *CurrentSF = C.getStackFrame();
+ if (SF == CurrentSF || !SF->isParentOf(CurrentSF))
+ return true;
+ }
+ return false;
+}
+
+template <typename MapTy, typename KeyTy>
+void LifetimeAnnotations::checkReturnedBorrower(const MapTy &Map,
+ const KeyTy RetKey,
+ ProgramStateRef State,
+ CheckerContext &C) const {
+ for (auto &&[Origin, SourceSet] : Map) {
+ if (Origin == RetKey) {
+ for (const MemRegion *Region : SourceSet) {
+ if (hasDanglingSource(Region, State, C))
+ if (ExplodedNode *N = C.generateNonFatalErrorNode())
+ reportDanglingSource(Region, N, C);
+ }
+ }
+ }
+}
+
+void LifetimeAnnotations::checkEndFunction(const ReturnStmt *RS,
+ CheckerContext &C) const {
+ if (!RS)
+ return;
+
+ ProgramStateRef State = C.getState();
+ auto LBMap = State->get<LifetimeBoundMap>();
+ auto LBMapVal = State->get<LifetimeBoundMapVal>();
+
+ if (LBMap.isEmpty() && LBMapVal.isEmpty())
+ return;
+
+ const Expr *RetExpr = RS->getRetValue();
+ if (!RetExpr)
+ return;
+
+ RetExpr = RetExpr->IgnoreParens();
+ SVal RetVal = C.getSVal(RetExpr);
+
+ SymbolRef RetValSym = RetVal.getAsSymbol(/*IncludeBaseRegions=*/true);
+ const MemRegion *RetValRegion = RetVal.getAsRegion();
+ if (!RetValSym && !RetValRegion)
+ return;
+
+ if (RetValSym)
+ checkReturnedBorrower(LBMap, RetValSym, State, C);
+
+ if (RetValRegion)
+ checkReturnedBorrower(LBMapVal, RetValRegion, State, C);
+}
+
+void LifetimeAnnotations::checkLifetimeEnd(const VarDecl *VD,
+ CheckerContext &C) const {
+ ProgramStateRef State = C.getState();
+ if (!VD)
+ return;
+
+ SVal SourceVal = State->getLValue(VD, C.getStackFrame());
+ if (const MemRegion *SourceRegion = SourceVal.getAsRegion()) {
+ State = State->add<DeadSourceSet>(SourceRegion);
+ C.addTransition(State);
+ }
+}
+
+void LifetimeAnnotations::reportDanglingBorrower(const LifetimeSourceSet
*Sources, CheckerContext &C) const {
+ ProgramStateRef State = C.getState();
+
+ for (const MemRegion *Source : *Sources) {
+ if (State->contains<DeadSourceSet>(Source)) {
+ if (ExplodedNode *N = C.generateNonFatalErrorNode())
+ reportUseAfterScope(Source, N, C);
+ }
+ }
+}
+
+void LifetimeAnnotations::checkLocation(SVal Loc, bool IsLoad, const Stmt *S,
+ CheckerContext &C) const {
+ ProgramStateRef State = C.getState();
+ auto LBMap = State->get<LifetimeBoundMap>();
+ auto LBMapVal = State->get<LifetimeBoundMapVal>();
+
+ // FIXME: Because of the CFG::LifetimeEnd elements now the analyzer can
+ // reason about out-of-scope dangling pointer deref even if there is
+ // no annotations in the source code. This detection part of the detection
+ // should live in a separate checker.
+ if (const MemRegion *R = Loc.getAsRegion()) {
+ if (State->contains<DeadSourceSet>(R)) {
+ if (ExplodedNode *N = C.generateNonFatalErrorNode())
+ reportUseAfterScope(R, N, C);
+ }
+ }
+
+ if (LBMap.isEmpty() && LBMapVal.isEmpty())
+ return;
+
+ // FIXME: If a borrower has multiple bound sources the callback warns
----------------
Xazax-hun wrote:
When we do not see the body (we apply the annotations), we cannot actually know
which source the borrower points to. But we probably will add a path note to
the diagnostic explaining the users what happened.
https://github.com/llvm/llvm-project/pull/200145
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