https://github.com/hokein created https://github.com/llvm/llvm-project/pull/114044
This fixes a bug raised in https://github.com/llvm/llvm-project/pull/112751#issuecomment-2443566707. >From 32d808a6c30cb572c7905f93b9c14b5d8a25599d Mon Sep 17 00:00:00 2001 From: Haojian Wu <hokein...@gmail.com> Date: Tue, 29 Oct 2024 13:53:35 +0100 Subject: [PATCH] [clang] Don't consider the lifetimeboundCall when analyzing the gsl pointer construction. --- clang/lib/Sema/CheckExprLifetime.cpp | 23 +++++++++++- .../Sema/warn-lifetime-analysis-nocfg.cpp | 37 ++++++++++++++++--- clang/test/SemaCXX/attr-lifetimebound.cpp | 2 +- 3 files changed, 55 insertions(+), 7 deletions(-) diff --git a/clang/lib/Sema/CheckExprLifetime.cpp b/clang/lib/Sema/CheckExprLifetime.cpp index aa0a2e223e708f..b19b320fe30228 100644 --- a/clang/lib/Sema/CheckExprLifetime.cpp +++ b/clang/lib/Sema/CheckExprLifetime.cpp @@ -1094,6 +1094,24 @@ static bool pathOnlyHandlesGslPointer(IndirectLocalPath &Path) { return false; } +static bool +isLifetimeboundInterleaveInGSL(llvm::ArrayRef<IndirectLocalPathEntry> PathRef) { + if (auto FirstGSLPointer = llvm::find_if( + PathRef, + [](const IndirectLocalPathEntry &Path) { + return Path.Kind == IndirectLocalPathEntry::GslPointerInit || + Path.Kind == IndirectLocalPathEntry::GslPointerAssignment; + }); + FirstGSLPointer != PathRef.end()) { + return llvm::find_if( + PathRef.drop_front(FirstGSLPointer - PathRef.begin() + 1), + [](const IndirectLocalPathEntry &Path) { + return Path.Kind == IndirectLocalPathEntry::LifetimeBoundCall; + }) != PathRef.end(); + } + return false; +} + static bool isAssignmentOperatorLifetimeBound(CXXMethodDecl *CMD) { if (!CMD) return false; @@ -1141,7 +1159,8 @@ static void checkExprLifetimeImpl(Sema &SemaRef, // someContainer.add(std::move(localUniquePtr)); // return p; IsLocalGslOwner = isRecordWithAttr<OwnerAttr>(L->getType()); - if (pathContainsInit(Path) || !IsLocalGslOwner) + if (pathContainsInit(Path) || !IsLocalGslOwner || + isLifetimeboundInterleaveInGSL(Path)) return false; } else { IsGslPtrValueFromGslTempOwner = @@ -1152,6 +1171,8 @@ static void checkExprLifetimeImpl(Sema &SemaRef, // a local or temporary owner or the address of a local variable/param. if (!IsGslPtrValueFromGslTempOwner) return true; + if (isLifetimeboundInterleaveInGSL(Path)) + return false; } } diff --git a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp index 688f55edfe84df..b97e34840c0d9b 100644 --- a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp +++ b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp @@ -714,8 +714,8 @@ struct [[gsl::Pointer]] Span { // Pointer from Owner<Pointer> std::string_view test5() { - std::string_view a = StatusOr<std::string_view>().valueLB(); // expected-warning {{object backing the pointer will be dest}} - return StatusOr<std::string_view>().valueLB(); // expected-warning {{returning address of local temporary}} + std::string_view a = StatusOr<std::string_view>().valueLB(); + return StatusOr<std::string_view>().valueLB(); // No dangling diagnostics on non-lifetimebound methods. std::string_view b = StatusOr<std::string_view>().valueNoLB(); @@ -746,7 +746,7 @@ std::vector<int*> test8(StatusOr<std::vector<int*>> aa) { // Pointer<Pointer> from Owner<Owner<Pointer>> Span<int*> test9(StatusOr<std::vector<int*>> aa) { - return aa.valueLB(); // expected-warning {{address of stack memory associated}} + return aa.valueLB(); // return aa.valueNoLB(); // OK. } @@ -754,7 +754,7 @@ Span<int*> test9(StatusOr<std::vector<int*>> aa) { // Pointer<Owner>> from Owner<Owner> Span<std::string> test10(StatusOr<std::vector<std::string>> aa) { - return aa.valueLB(); // expected-warning {{address of stack memory}} + return aa.valueLB(); // return aa.valueNoLB(); // OK. } @@ -762,7 +762,7 @@ Span<std::string> test10(StatusOr<std::vector<std::string>> aa) { // Pointer<Owner>> from Owner<Pointer<Owner>> Span<std::string> test11(StatusOr<Span<std::string>> aa) { - return aa.valueLB(); // expected-warning {{address of stack memory}} + return aa.valueLB(); // return aa.valueNoLB(); // OK. } @@ -780,3 +780,30 @@ void test13() { } } // namespace GH100526 + +namespace test { + +struct [[gsl::Pointer]] FooOwner {}; +struct [[gsl::Pointer]] FooPointer { + FooPointer(const FooOwner&); +}; + +template<typename T> +struct [[gsl::Owner]] Container { + const T& get() const [[clang::lifetimebound]]; +}; + +FooPointer func() { + Container<FooPointer> foo; + + FooPointer p = Container<FooPointer>().get(); + p = Container<FooPointer>().get(); + return foo.get(); + + FooPointer p2 = Container<FooOwner>().get(); + p2 = Container<FooOwner>().get(); + Container<FooOwner> foo2; + return foo2.get(); +} + +} diff --git a/clang/test/SemaCXX/attr-lifetimebound.cpp b/clang/test/SemaCXX/attr-lifetimebound.cpp index 804d61fb62ca40..70a80affceda54 100644 --- a/clang/test/SemaCXX/attr-lifetimebound.cpp +++ b/clang/test/SemaCXX/attr-lifetimebound.cpp @@ -153,7 +153,7 @@ namespace p0936r0_examples { void f() { std::string_view sv = "hi"; std::string_view sv2 = sv + sv; // expected-warning {{temporary}} - sv2 = sv + sv; // expected-warning {{object backing the pointer}} + sv2 = sv + sv; // FIXME: warn here too. } struct X { int a, b; }; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
