Author: Aaron Ballman Date: 2025-05-19T11:28:48-04:00 New Revision: 7cf2860cbdc158a04d4a982fa7043cd9e6401e77
URL: https://github.com/llvm/llvm-project/commit/7cf2860cbdc158a04d4a982fa7043cd9e6401e77 DIFF: https://github.com/llvm/llvm-project/commit/7cf2860cbdc158a04d4a982fa7043cd9e6401e77.diff LOG: [C++] Fix a crash with __thread and dependent types (#140542) We were checking whether the initializer is a valid constant expression even if the variable was dependent. Now we delay that checking until after the template has been instantiated. Fixes #140509 Added: clang/test/SemaCXX/thread-specifier.cpp Modified: clang/docs/ReleaseNotes.rst clang/lib/Sema/SemaDecl.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 4a3c1bee82831..472b70b46fcc0 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -558,6 +558,9 @@ Improvements to Clang's diagnostics between diff erent Unicode character types (``char8_t``, ``char16_t``, ``char32_t``). This warning only triggers in C++ as these types are aliases in C. (#GH138526) +- Fixed a crash when checking a ``__thread``-specified variable declaration + with a dependent type in C++. (#GH140509) + Improvements to Clang's time-trace ---------------------------------- diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index d47c1d39adf92..ad0e274d02ef5 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -14608,6 +14608,10 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) { std::optional<bool> CacheHasConstInit; const Expr *CacheCulprit = nullptr; auto checkConstInit = [&]() mutable { + const Expr *Init = var->getInit(); + if (Init->isInstantiationDependent()) + return true; + if (!CacheHasConstInit) CacheHasConstInit = var->getInit()->isConstantInitializer( Context, var->getType()->isReferenceType(), &CacheCulprit); diff --git a/clang/test/SemaCXX/thread-specifier.cpp b/clang/test/SemaCXX/thread-specifier.cpp new file mode 100644 index 0000000000000..2b909ecd175d0 --- /dev/null +++ b/clang/test/SemaCXX/thread-specifier.cpp @@ -0,0 +1,30 @@ +// RUN: %clang_cc1 -fsyntax-only -std=c++23 -verify %s + +namespace GH140509 { +template <typename T> +void not_instantiated() { + static __thread T my_wrapper; +} + +template <typename T> +void instantiated() { + static __thread T my_wrapper = T{}; // expected-error {{initializer for thread-local variable must be a constant expression}} \ + expected-note {{use 'thread_local' to allow this}} +} + +template <typename T> +void nondependent_var() { + // Verify that the dependence of the initializer is what really matters. + static __thread int my_wrapper = T{}; +} + +struct S { + S() {} +}; + +void f() { + instantiated<int>(); + instantiated<S>(); // expected-note {{in instantiation of function template specialization 'GH140509::instantiated<GH140509::S>' requested here}} + nondependent_var<int>(); +} +} // namespace GH140509 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
