https://github.com/AaronBallman updated https://github.com/llvm/llvm-project/pull/228207
>From 73167de01e77b7566a0ccc8e79d26e62468dec0c Mon Sep 17 00:00:00 2001 From: Aaron Ballman <[email protected]> Date: Thu, 1 Oct 2026 15:19:37 -0400 Subject: [PATCH] [clang] Fix crashes with inheritance model keywords The inheritance model keywords support a single underscore alias, but that alias was never added to Attr.td. When we added typo correction support for attributes in Clang 21, this uncovered a bug with these keywords when a single underscore variant was used because the hasAttribute() logic didn't know about these spellings. This adds the correct spellings for the aliases to Attr.td. While working on that, I noticed that we were missing an alias for _single_inheritance, which is supported by MSVC, so that was added as a drive-by fix. Fixes #228003 --- clang/docs/ReleaseNotes.md | 3 +++ clang/include/clang/Basic/Attr.td | 11 ++++++++++- clang/include/clang/Basic/TokenKinds.def | 1 + clang/test/Parser/MicrosoftExtensions.cpp | 7 +++++++ 4 files changed, 21 insertions(+), 1 deletion(-) diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index 8160c5298e4197..6052325b0dc526 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -296,6 +296,8 @@ features cannot lower the translation-unit ABI level; - Clang now recognizes the `[[gnu::flag_enum]]` attribute and treats it equivalent to `[[clang::flag_enum]]` +- Clang now accepts `_single_inheritance` under `-fms-compatibility` as an alias for `__single_inheritance`; `_multiple_inheritance` and `_virtual_inheritance` were already correctly supported as aliases. + ### Improvements to Clang's diagnostics - `-Wfortify-source` now diagnoses when `strlcat`, `__builtin_strlcat`, `strlcpy`, or @@ -580,6 +582,7 @@ features cannot lower the translation-unit ABI level; (e.g. `({ s.b; })`) was not subject to integer promotion, unlike an ordinary bit-field access. (#GH221542) - No longer crashing due to follow-on diagnostics when there is an invalid operand in a logical operator involving a vector operand. (#GH227588) +- Fixed a crash due to typo correction mishandling custom keywords `_virtual_inheritance` and `_multiple_inheritance` in `-fms-compatibility` mode. (#GH228003) #### Bug Fixes to Compiler Builtins diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td index 6d3f50e1d2e20b..3824a8e21e4cb5 100644 --- a/clang/include/clang/Basic/Attr.td +++ b/clang/include/clang/Basic/Attr.td @@ -4623,7 +4623,16 @@ def MSInheritance : InheritableAttr { let Spellings = [CustomKeyword<"__single_inheritance">, CustomKeyword<"__multiple_inheritance">, CustomKeyword<"__virtual_inheritance">, - CustomKeyword<"__unspecified_inheritance">]; + CustomKeyword<"__unspecified_inheritance">, + // The single underscore spellings are aliases defined in + // TokenKinds.def; they must come *after* all of the other + // spellings because otherwise the MSInheritanceModel + // enumeration will break (we're relying on token + // normalization converting the alias to the normal form). + CustomKeyword<"_single_inheritance">, + CustomKeyword<"_multiple_inheritance">, + CustomKeyword<"_virtual_inheritance"> + ]; let AdditionalMembers = [{ MSInheritanceModel getInheritanceModel() const { // The spelling enum should agree with MSInheritanceModel. diff --git a/clang/include/clang/Basic/TokenKinds.def b/clang/include/clang/Basic/TokenKinds.def index 97e5915bcd0d5e..213f2492d96f40 100644 --- a/clang/include/clang/Basic/TokenKinds.def +++ b/clang/include/clang/Basic/TokenKinds.def @@ -657,6 +657,7 @@ ALIAS("_multiple_inheritance", __multiple_inheritance, KEYMSCOMPAT) ALIAS("_ptr32" , __ptr32 , KEYMSCOMPAT) ALIAS("_ptr64" , __ptr64 , KEYMSCOMPAT) ALIAS("_restrict" , restrict , KEYMSCOMPAT) +ALIAS("_single_inheritance", __single_inheritance, KEYMSCOMPAT) ALIAS("_stdcall" , __stdcall , KEYMS | KEYBORLAND) ALIAS("_thiscall" , __thiscall , KEYMS) ALIAS("_try" , __try , KEYMSCOMPAT) diff --git a/clang/test/Parser/MicrosoftExtensions.cpp b/clang/test/Parser/MicrosoftExtensions.cpp index e32d7fae6af399..ee23596df46f63 100644 --- a/clang/test/Parser/MicrosoftExtensions.cpp +++ b/clang/test/Parser/MicrosoftExtensions.cpp @@ -349,6 +349,13 @@ namespace Inheritance { class __single_inheritance A; class __multiple_inheritance B; class __virtual_inheritance C; + + // The single underscore variants are the same as the double underscore ones. + // Some of these would crash due to typo correction because the spellings + // were missing from Attr.td but supported by TokenKinds.def. See GH228003. + class _single_inheritance D; + class _multiple_inheritance E; + class _virtual_inheritance F; } struct StructWithProperty { _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
