Author: Discookie Date: 2025-03-04T10:38:06Z New Revision: 680391f07a45272bb9bfd385cf4c6846b8be32dd
URL: https://github.com/llvm/llvm-project/commit/680391f07a45272bb9bfd385cf4c6846b8be32dd DIFF: https://github.com/llvm/llvm-project/commit/680391f07a45272bb9bfd385cf4c6846b8be32dd.diff LOG: [clang][dataflow] Fix unsupported types always being equal (#129502) Previously when the framework encountered unsupported values (such as enum classes), they were always treated as equal when comparing with `==`, regardless of their actual values being different. Now the two sides are only equal if there's a Value assigned to them. Added a Value assignment for `nullptr`, to handle the special case of `nullptr == nullptr`. Added: Modified: clang/lib/Analysis/FlowSensitive/Transfer.cpp clang/unittests/Analysis/FlowSensitive/TransferTest.cpp Removed: ################################################################################ diff --git a/clang/lib/Analysis/FlowSensitive/Transfer.cpp b/clang/lib/Analysis/FlowSensitive/Transfer.cpp index 9c54eb16d2224..e17a16a3b75d0 100644 --- a/clang/lib/Analysis/FlowSensitive/Transfer.cpp +++ b/clang/lib/Analysis/FlowSensitive/Transfer.cpp @@ -60,7 +60,9 @@ static BoolValue &evaluateBooleanEquality(const Expr &LHS, const Expr &RHS, Value *LHSValue = Env.getValue(LHS); Value *RHSValue = Env.getValue(RHS); - if (LHSValue == RHSValue) + // When two unsupported values are compared, both are nullptr. Only supported + // values should evaluate to equal. + if (LHSValue == RHSValue && LHSValue) return Env.getBoolLiteralValue(true); if (auto *LHSBool = dyn_cast_or_null<BoolValue>(LHSValue)) @@ -798,6 +800,14 @@ class TransferVisitor : public ConstStmtVisitor<TransferVisitor> { Env.setValue(*S, Env.getIntLiteralValue(S->getValue())); } + // Untyped nullptr's aren't handled by NullToPointer casts, so they need to be + // handled separately. + void VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *S) { + auto &NullPointerVal = + Env.getOrCreateNullPointerValue(S->getType()->getPointeeType()); + Env.setValue(*S, NullPointerVal); + } + void VisitParenExpr(const ParenExpr *S) { // The CFG does not contain `ParenExpr` as top-level statements in basic // blocks, however manual traversal to sub-expressions may encounter them. diff --git a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp index 0f731f4532535..f52b73dbbdc57 100644 --- a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp +++ b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp @@ -4974,6 +4974,41 @@ TEST(TransferTest, IntegerLiteralEquality) { }); } +TEST(TransferTest, UnsupportedValueEquality) { + std::string Code = R"( + // An explicitly unsupported type by the framework. + enum class EC { + A, + B + }; + + void target() { + EC ec = EC::A; + + bool unsupported_eq_same = (EC::A == EC::A); + bool unsupported_eq_other = (EC::A == EC::B); + bool unsupported_eq_var = (ec == EC::B); + + (void)0; // [[p]] + } + )"; + runDataflow( + Code, + [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results, + ASTContext &ASTCtx) { + const Environment &Env = getEnvironmentAtAnnotation(Results, "p"); + + // We do not model the values of unsupported types, so this + // seemingly-trivial case will not be true either. + EXPECT_TRUE(isa<AtomicBoolValue>( + getValueForDecl<BoolValue>(ASTCtx, Env, "unsupported_eq_same"))); + EXPECT_TRUE(isa<AtomicBoolValue>( + getValueForDecl<BoolValue>(ASTCtx, Env, "unsupported_eq_other"))); + EXPECT_TRUE(isa<AtomicBoolValue>( + getValueForDecl<BoolValue>(ASTCtx, Env, "unsupported_eq_var"))); + }); +} + TEST(TransferTest, CorrelatedBranches) { std::string Code = R"( void target(bool B, bool C) { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
