Author: Eric Li Date: 2022-05-25T20:58:02Z New Revision: 33b598a808b9ef1a019e798f19855f203e09ad48
URL: https://github.com/llvm/llvm-project/commit/33b598a808b9ef1a019e798f19855f203e09ad48 DIFF: https://github.com/llvm/llvm-project/commit/33b598a808b9ef1a019e798f19855f203e09ad48.diff LOG: [clang][dataflow] Relax assert on existence of `this` pointee storage Support for unions is incomplete (per 99f7d55e) and the `this` pointee storage location is not set for unions. The assert in `VisitCXXThisExpr` is then guaranteed to trigger when analyzing member functions of a union. This commit changes the assert to an early-return. Any expression may be undefined, and so having a value for the `CXXThisExpr` is not a postcondition of the transfer function. Differential Revision: https://reviews.llvm.org/D126405 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 f88406595d728..fc04e0b55ffc7 100644 --- a/clang/lib/Analysis/FlowSensitive/Transfer.cpp +++ b/clang/lib/Analysis/FlowSensitive/Transfer.cpp @@ -279,7 +279,10 @@ class TransferVisitor : public ConstStmtVisitor<TransferVisitor> { void VisitCXXThisExpr(const CXXThisExpr *S) { auto *ThisPointeeLoc = Env.getThisPointeeStorageLocation(); - assert(ThisPointeeLoc != nullptr); + if (ThisPointeeLoc == nullptr) + // Unions are not supported yet, and will not have a location for the + // `this` expression's pointee. + return; auto &Loc = Env.createStorageLocation(*S); Env.setStorageLocation(*S, Loc); diff --git a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp index b6d2940a98daa..bb6e269969da7 100644 --- a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp +++ b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp @@ -42,10 +42,11 @@ class TransferTest : public ::testing::Test { template <typename Matcher> void runDataflow(llvm::StringRef Code, Matcher Match, LangStandard::Kind Std = LangStandard::lang_cxx17, - bool ApplyBuiltinTransfer = true) { + bool ApplyBuiltinTransfer = true, + llvm::StringRef TargetFun = "target") { ASSERT_THAT_ERROR( test::checkDataflow<NoopAnalysis>( - Code, "target", + Code, TargetFun, [ApplyBuiltinTransfer](ASTContext &C, Environment &) { return NoopAnalysis(C, ApplyBuiltinTransfer); }, @@ -3175,4 +3176,27 @@ TEST_F(TransferTest, LoopWithStructReferenceAssignmentConverges) { }); } +TEST_F(TransferTest, DoesNotCrashOnUnionThisExpr) { + std::string Code = R"( + union Union { + int A; + float B; + }; + + void foo() { + Union A; + Union B; + A = B; + } + )"; + // This is a crash regression test when calling the transfer function on a + // `CXXThisExpr` that refers to a union. + runDataflow( + Code, + [](llvm::ArrayRef< + std::pair<std::string, DataflowAnalysisState<NoopLattice>>>, + ASTContext &) {}, + LangStandard::lang_cxx17, /*ApplyBuiltinTransfer=*/true, "operator="); +} + } // namespace _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
