https://github.com/usx95 updated
https://github.com/llvm/llvm-project/pull/148712
>From 111163fc65843dfd135d60bb45b1311a21d60338 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <u...@google.com>
Date: Mon, 14 Jul 2025 19:32:35 +0000
Subject: [PATCH 1/2] users/usx95/lifetime-safety-add-loan-expiry
>From 5f0991338d17813d9af276a0cea2d30875a9aa23 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <u...@google.com>
Date: Mon, 14 Jul 2025 19:37:49 +0000
Subject: [PATCH 2/2] [LifetimeSafety] Add loan expiry analysis
---
clang/lib/Analysis/LifetimeSafety.cpp | 64 +++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/clang/lib/Analysis/LifetimeSafety.cpp
b/clang/lib/Analysis/LifetimeSafety.cpp
index f9a7093987896..217b02b416c1a 100644
--- a/clang/lib/Analysis/LifetimeSafety.cpp
+++ b/clang/lib/Analysis/LifetimeSafety.cpp
@@ -518,6 +518,8 @@ enum class Direction { Forward, Backward };
/// analysis.
/// \tparam LatticeType The dataflow lattice used by the analysis.
/// \tparam Dir The direction of the analysis (Forward or Backward).
+/// TODO: Maybe use the dataflow framework! The framework might need changes
+/// to support the current comparison done at block-entry.
template <typename Derived, typename LatticeType, Direction Dir>
class DataflowAnalysis {
public:
@@ -775,6 +777,65 @@ class LoanPropagationAnalysis
}
};
+// ========================================================================= //
+// Expired Loans Analysis
+// ========================================================================= //
+
+/// The dataflow lattice for tracking the set of expired loans.
+struct ExpiredLattice {
+ LoanSet Expired;
+
+ ExpiredLattice() : Expired(nullptr) {};
+ explicit ExpiredLattice(LoanSet S) : Expired(S) {}
+
+ bool operator==(const ExpiredLattice &Other) const {
+ return Expired == Other.Expired;
+ }
+ bool operator!=(const ExpiredLattice &Other) const {
+ return !(*this == Other);
+ }
+
+ void dump(llvm::raw_ostream &OS) const {
+ OS << "ExpiredLattice State:\n";
+ if (Expired.isEmpty())
+ OS << " <empty>\n";
+ for (const LoanID &LID : Expired)
+ OS << " Loan " << LID << " is expired\n";
+ }
+};
+
+/// The analysis that tracks which loans have expired.
+class ExpiredLoansAnalysis
+ : public DataflowAnalysis<ExpiredLoansAnalysis, ExpiredLattice,
+ Direction::Forward> {
+
+ LoanSet::Factory &Factory;
+
+public:
+ ExpiredLoansAnalysis(const CFG &C, AnalysisDeclContext &AC, FactManager &F,
+ LifetimeFactory &SF)
+ : DataflowAnalysis(C, AC, F), Factory(SF.LoanSetFactory) {}
+
+ using Base::transfer;
+
+ StringRef getAnalysisName() const { return "ExpiredLoans"; }
+
+ Lattice getInitialState() { return Lattice(Factory.getEmptySet()); }
+
+ /// Merges two lattices by taking the union of the expired loan sets.
+ Lattice join(Lattice L1, Lattice L2) const {
+ return Lattice(utils::join(L1.Expired, L2.Expired, Factory));
+ }
+
+ Lattice transfer(Lattice In, const ExpireFact &F) {
+ return Lattice(Factory.add(In.Expired, F.getLoanID()));
+ }
+
+ Lattice transfer(Lattice In, const IssueFact &F) {
+ return Lattice(Factory.remove(In.Expired, F.getLoanID()));
+ }
+};
+
// ========================================================================= //
// TODO:
// - Modifying loan propagation to answer `LoanSet getLoans(Origin O, Point P)`
@@ -807,5 +868,8 @@ void runLifetimeSafetyAnalysis(const DeclContext &DC, const
CFG &Cfg,
LoanPropagationAnalysis LoanPropagation(Cfg, AC, FactMgr, Factory);
LoanPropagation.run();
DEBUG_WITH_TYPE("LifetimeLoanPropagation", LoanPropagation.dump());
+
+ ExpiredLoansAnalysis ExpiredLoans(Cfg, AC, FactMgr, Factory);
+ ExpiredLoans.run();
}
} // namespace clang
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