Author: Alexander Kornienko Date: 2024-07-26T14:24:56+02:00 New Revision: 8322a3085c902de9759a40ccdcd194a4c46e7185
URL: https://github.com/llvm/llvm-project/commit/8322a3085c902de9759a40ccdcd194a4c46e7185 DIFF: https://github.com/llvm/llvm-project/commit/8322a3085c902de9759a40ccdcd194a4c46e7185.diff LOG: Avoid accessing unset optional, workaround for #100095 (#100408) This patch avoids accessing an unset `std::optional<>`, which is a part of the manifestation of #100095. The other part is an assertion failure that is not addressed here. This is not a proper fix, but enables Clang to continue working with more libc++ runtime checks enabled (specifically, `-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_FAST`, which checks access to unset optionals among other things). A proper fix is being discussed on #100095. Added: clang/test/SemaCXX/pr100095.cpp Modified: clang/lib/Sema/SemaTemplateDeduction.cpp Removed: ################################################################################ diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp index b7b857ebf804b..db7f233dcef73 100644 --- a/clang/lib/Sema/SemaTemplateDeduction.cpp +++ b/clang/lib/Sema/SemaTemplateDeduction.cpp @@ -951,9 +951,11 @@ class PackDeductionScope { // Skip over the pack elements that were expanded into separate arguments. // If we partially expanded, this is the number of partial arguments. + // FIXME: `&& FixedNumExpansions` is a workaround for UB described in + // https://github.com/llvm/llvm-project/issues/100095 if (IsPartiallyExpanded) PackElements += NumPartialPackArgs; - else if (IsExpanded) + else if (IsExpanded && FixedNumExpansions) PackElements += *FixedNumExpansions; for (auto &Pack : Packs) { diff --git a/clang/test/SemaCXX/pr100095.cpp b/clang/test/SemaCXX/pr100095.cpp new file mode 100644 index 0000000000000..15913fec9d5ae --- /dev/null +++ b/clang/test/SemaCXX/pr100095.cpp @@ -0,0 +1,17 @@ +// RUN: %clang_cc1 -fsyntax-only -std=c++11 %s +// XFAIL: asserts + +template <class> struct Pair; +template <class...> struct Tuple { + template <class _Up> Tuple(_Up); +}; +template <typename> struct StatusOr; +template <int> using ElementType = int; +template <int... fields> +using Key = Tuple<ElementType<fields>...>; +template <int... fields> +StatusOr<Pair<Key<fields...>>> Parser(); +struct Helper { Helper(Tuple<>, Tuple<>, int, int); }; +struct D : Helper { + D(Key<> f, int n, int e) : Helper(f, Parser<>, n, e) {} +}; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
