================
@@ -0,0 +1,305 @@
+#include "clang/Analysis/Analyses/LifetimeSafety/LifetimeAnnotations.h"
+#include "clang/AST/Attrs.inc"
+#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, SVal, LifetimeSourceSet)
+
+REGISTER_SET_WITH_PROGRAMSTATE(DeallocatedSourceSet, const MemRegion *)
+
+namespace {
+class LifetimeAnnotations
+ : public Checker<check::PostCall, check::EndFunction, check::Location,
+ check::DeadSymbols> {
+public:
+ void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
+ void printState(raw_ostream &Out, ProgramStateRef State, const char *NL,
+ const char *Sep) const override;
+ void reportDanglingSource(const MemRegion *Region, ExplodedNode *N,
+ CheckerContext &C) const;
+ void reportUseAfterScope(const MemRegion *Region, ExplodedNode *N,
+ CheckerContext &C) const;
+
+ void checkReturnedBorrower(SVal Val, ProgramStateRef State,
+ CheckerContext &C) const;
+ void reportDanglingBorrower(const LifetimeSourceSet *Sources,
+ CheckerContext &C) const;
+ void checkEndFunction(const ReturnStmt *RS, 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
+
+static ProgramStateRef bindValues(ProgramStateRef State, SVal RetVal,
+ const MemRegion *Source) {
+ LifetimeSourceSet::Factory &F =
+ State->getStateManager().get_context<LifetimeSourceSet>();
+
+ const LifetimeSourceSet *LSet = State->get<LifetimeBoundMap>(RetVal);
+ LifetimeSourceSet Set = LSet ? *LSet : F.getEmptySet();
+ Set = F.add(Set, Source);
+ State = State->set<LifetimeBoundMap>(RetVal, 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);
+}
+
+static bool hasDanglingSource(const MemRegion *Source, ProgramStateRef State,
+ CheckerContext &C) {
+ // FIXME: The checker currently handles stack-region sources. Other
+ // region kinds require separate methodology. For example, heap
+ // regions do not go out of scope at the end of a stack frame, so
+ // in order to detect those type of dangling sources the function
+ // needs to be expanded to an event-driven approach as well.
+ 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;
+}
+
+void LifetimeAnnotations::checkReturnedBorrower(SVal Val, ProgramStateRef
State,
+ CheckerContext &C) const {
+ if (auto *SourceSet = State->get<LifetimeBoundMap>(Val)) {
+ if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
+ for (const MemRegion *Region : *SourceSet) {
+ if (hasDanglingSource(Region, State, C))
+ 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>();
+
+ if (LBMap.isEmpty())
+ return;
+
+ const Expr *RetExpr = RS->getRetValue();
+ if (!RetExpr)
+ return;
+
+ RetExpr = RetExpr->IgnoreParens();
+ SVal RetVal = C.getSVal(RetExpr);
+ checkReturnedBorrower(RetVal, State, C);
+}
+
+void LifetimeAnnotations::reportDanglingBorrower(
+ const LifetimeSourceSet *Sources, CheckerContext &C) const {
+ ProgramStateRef State = C.getState();
+
+ ExplodedNode *N = C.generateNonFatalErrorNode();
+ if (!N)
+ return;
+
+ for (const MemRegion *Source : *Sources) {
+ if (State->contains<DeallocatedSourceSet>(Source)) {
+ 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>();
+
+ if (LBMap.isEmpty())
+ return;
+
+ // FIXME: If a borrower has multiple bound sources the callback
+ // warns if any of the sources have died. PathDiagnosticVisitor
+ // should be used to trace and identify which annotated parameter
+ // recorded the binding. Attaching this information as path notes
+ // would make the diagnostics more useful to the user.
+ if (auto *SourceSet = State->get<LifetimeBoundMap>(Loc))
+ reportDanglingBorrower(SourceSet, C);
+}
+
+void LifetimeAnnotations::reportDanglingSource(const MemRegion *Region,
+ ExplodedNode *N,
+ CheckerContext &C) const {
+ auto BR = std::make_unique<PathSensitiveBugReport>(
+ BugMsg,
+ (llvm::Twine("Returning value bound to '") + Region->getString() +
+ "' that will go out of scope")
+ .str(),
+ N);
+ C.emitReport(std::move(BR));
+}
+
+void LifetimeAnnotations::reportUseAfterScope(const MemRegion *Region,
+ ExplodedNode *N,
+ CheckerContext &C) const {
+ auto BR = std::make_unique<PathSensitiveBugReport>(
+ BugMsg,
+ (llvm::Twine("Use of '") + Region->getString() +
+ "' after its lifetime ended.")
+ .str(),
+ N);
+ C.emitReport(std::move(BR));
+}
+
+void LifetimeAnnotations::checkDeadSymbols(SymbolReaper &SymReaper,
+ CheckerContext &C) const {
+ ProgramStateRef State = C.getState();
+ LifetimeBoundMapTy LBMap = State->get<LifetimeBoundMap>();
+
+ DeallocatedSourceSetTy Sources = State->get<DeallocatedSourceSet>();
+
+ for (SVal Val : llvm::make_first_range(LBMap)) {
+ if (const MemRegion *ValRegion = Val.getAsRegion()) {
+ if (!SymReaper.isLiveRegion(ValRegion))
+ State = State->remove<LifetimeBoundMap>(Val);
+ } else if (SymbolRef ValRef =
+ Val.getAsSymbol(/*IncludeBaseRegions=*/true)) {
+ if (!SymReaper.isLive(ValRef))
+ State = State->remove<LifetimeBoundMap>(Val);
+ }
+ }
+
+ for (const MemRegion *Region : Sources) {
+ if (!SymReaper.isLiveRegion(Region))
+ State = State->remove<DeallocatedSourceSet>(Region);
+ }
+
+ C.addTransition(State);
+}
+
+void LifetimeAnnotations::printState(raw_ostream &Out, ProgramStateRef State,
+ const char *NL, const char *Sep) const {
+ auto LBMap = State->get<LifetimeBoundMap>();
+
+ if (LBMap.isEmpty())
+ return;
+
+ Out << Sep << "LifetimeBound bindings:" << NL;
+ for (auto &&[OriginSym, SourceSet] : LBMap) {
+ for (const auto *Region : SourceSet)
+ Out << " Origin " << OriginSym << " contains Loan " << Region << NL;
+ }
+}
+
+namespace {
+class DebugLifetimeAnnotations : public Checker<eval::Call> {
+public:
+ bool evalCall(const CallEvent &Call, CheckerContext &C) const;
+ void analyzerLifetimeBound(const CallEvent &Call, CheckerContext &C) const;
+
+ const BugType BugMsg{this, "DebugLifetimeAnnotations", "DebugLifetimeBound"};
+ using FnCheck = void (DebugLifetimeAnnotations::*)(const CallEvent &Call,
+ CheckerContext &C) const;
+
+ const CallDescriptionMap<FnCheck> Callbacks = {
+ {{CDM::SimpleFunc, {"clang_analyzer_lifetime_bound"}},
+ &DebugLifetimeAnnotations::analyzerLifetimeBound},
+ };
+};
+
+} // namespace
+
+bool DebugLifetimeAnnotations::evalCall(const CallEvent &Call,
+ CheckerContext &C) const {
+
+ const auto *CE = dyn_cast_if_present<CallExpr>(Call.getOriginExpr());
+ if (!CE)
+ return false;
+
+ const FnCheck *Handler = Callbacks.lookup(Call);
+ if (!Handler)
+ return false;
+
+ (this->*(*Handler))(Call, C);
+ return true;
+}
+
+void DebugLifetimeAnnotations::analyzerLifetimeBound(const CallEvent &Call,
+ CheckerContext &C) const {
+
+ ProgramStateRef State = C.getState();
+ unsigned int ArgCount = Call.getNumArgs();
+ if (ArgCount != 1)
+ return;
+
+ SVal ArgSVal = Call.getArgSVal(0);
+
+ if (auto *SourceSet = State->get<LifetimeBoundMap>(ArgSVal)) {
+ if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
+ for (const auto *Region : *SourceSet) {
+ llvm::SmallString<128> Str;
+ llvm::raw_svector_ostream OS(Str);
+ OS << " Origin " << ArgSVal << " bound to " << Region;
+ auto BR = std::make_unique<PathSensitiveBugReport>(BugMsg, OS.str(),
N);
+ C.emitReport(std::move(BR));
+ }
+ }
+ }
+}
+
+void ento::registerLifetimeAnnotations(CheckerManager &mgr) {
+ mgr.registerChecker<LifetimeAnnotations>();
+}
+
+bool ento::shouldRegisterLifetimeAnnotations(const CheckerManager &mgr) {
+ return true;
+}
+
+void ento::registerDebugLifetimeAnnotations(CheckerManager &mgr) {
+ mgr.registerChecker<DebugLifetimeAnnotations>();
+}
+
+bool ento::shouldRegisterDebugLifetimeAnnotations(const CheckerManager &mgr) {
+ return true;
+}
----------------
steakhal wrote:
```suggestion
void ento::registerLifetimeAnnotations(CheckerManager &Mgr) {
Mgr.registerChecker<LifetimeAnnotations>();
}
bool ento::shouldRegisterLifetimeAnnotations(const CheckerManager &) {
return true;
}
void ento::registerDebugLifetimeAnnotations(CheckerManager &Mgr) {
Mgr.registerChecker<DebugLifetimeAnnotations>();
}
bool ento::shouldRegisterDebugLifetimeAnnotations(const CheckerManager &) {
return true;
}
```
https://github.com/llvm/llvm-project/pull/205521
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