https://gcc.gnu.org/g:8978da072f9ea7653416d59167a07e79be6cadaf
commit r16-7246-g8978da072f9ea7653416d59167a07e79be6cadaf Author: Patrick Palka <[email protected]> Date: Mon Feb 2 15:14:20 2026 -0500 libstdc++/regex: Zero-initialize _ExecutorFrame flags Prevents uninitialized read bugs, and it's also just natural to assume flags are initially cleared rather than uninitialized. In passing rename the _M_end flag to _M_subexpr_end to make it distinct from _Executor::_M_end. libstdc++-v3/ChangeLog: * include/bits/regex_executor.tcc (_ExecutorFrameBase): Zero-initialize _M_byte0. (_ExecutorFrameBase::_M_end): Rename to ... (_ExecutorFrameBase::_M_subexpr_end): ... this. (_Executor::_M_handle_subexpr_begin): Remove now redundant clearing of _M_subexpr_end. (_Executor::_M_handle_subexpr_end): Adjust after renaming. (_Executor::_M_dfs) <case _S_fopcode_restore_cur_results>: Likewise. Reviewed-by: Jonathan Wakely <[email protected]> Diff: --- libstdc++-v3/include/bits/regex_executor.tcc | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/libstdc++-v3/include/bits/regex_executor.tcc b/libstdc++-v3/include/bits/regex_executor.tcc index 6c8deff2f21e..19b5ad27df40 100644 --- a/libstdc++-v3/include/bits/regex_executor.tcc +++ b/libstdc++-v3/include/bits/regex_executor.tcc @@ -79,12 +79,12 @@ _GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2) _ExecutorFrameOpcode _M_op; union { - unsigned char _M_byte0; + unsigned char _M_byte0 = 0; struct { // Used by restore_rep_count frame unsigned char _M_count : 2; }; struct { // Used by restore_cur_results frame - unsigned char _M_end : 1; + unsigned char _M_subexpr_end : 1; unsigned char _M_matched : 1; }; }; @@ -338,7 +338,6 @@ _GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2) _M_frames.emplace_back(_S_fopcode_restore_cur_results, static_cast<_StateIdT>(__state._M_subexpr), __res.first); - _M_frames.back()._M_end = false; __res.first = _M_current; _M_frames.emplace_back(_S_fopcode_next, __state._M_next); } @@ -353,7 +352,7 @@ _GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2) _M_frames.emplace_back(_S_fopcode_restore_cur_results, static_cast<_StateIdT>(__state._M_subexpr), __res.second); - _M_frames.back()._M_end = true; + _M_frames.back()._M_subexpr_end = true; _M_frames.back()._M_matched = __res.matched; __res.second = _M_current; __res.matched = true; @@ -670,7 +669,7 @@ _GLIBCXX_BEGIN_INLINE_ABI_NAMESPACE(_V2) break; case _S_fopcode_restore_cur_results: - if (!__frame._M_end) + if (!__frame._M_subexpr_end) _M_cur_results[__frame._M_state_id].first = __frame._M_pos; else {
