https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117745
--- Comment #13 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-14 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:0183fb1cef5e382af2a5c0dc3c59efbcd32db6ab commit r14-11146-g0183fb1cef5e382af2a5c0dc3c59efbcd32db6ab Author: Jakub Jelinek <ja...@redhat.com> Date: Wed Nov 27 17:29:28 2024 +0100 c: Fix sizeof error recovery [PR117745] Compilation of the following testcase hangs forever after emitting first error. The problem is that in one place we just return error_mark_node directly rather than going through c_expr_sizeof_expr or c_expr_sizeof_type. The parsing of the expression could have called record_maybe_used_decl though, but nothing calls pop_maybe_used which needs to be called after parsing of every sizeof/typeof, successful or not. At the end of the toplevel declaration we free the parser_obstack and in another function record_maybe_used_decl is called again and due to the missing pop_maybe_unused we end up with a cycle in the chain. The following patch fixes it by just setting error and goto to the sizeof_expr: c_inhibit_evaluation_warnings--; in_sizeof--; mark_exp_read (expr.value); if (TREE_CODE (expr.value) == COMPONENT_REF && DECL_C_BIT_FIELD (TREE_OPERAND (expr.value, 1))) error_at (expr_loc, "%<sizeof%> applied to a bit-field"); result = c_expr_sizeof_expr (expr_loc, expr); where c_expr_sizeof_expr will do: struct c_expr ret; if (expr.value == error_mark_node) { ret.value = error_mark_node; ret.original_code = ERROR_MARK; ret.original_type = NULL; ret.m_decimal = 0; pop_maybe_used (false); } ... return ret; which is exactly what the old code did manually except for the missing pop_maybe_used call. mark_exp_read does nothing on error_mark_node and error_mark_node doesn't have COMPONENT_REF tree_code. 2024-11-27 Jakub Jelinek <ja...@redhat.com> PR c/117745 * c-parser.cc (c_parser_sizeof_expression): If type_name is NULL, just expr.set_error () and goto sizeof_expr instead of doing error recovery manually. * gcc.dg/pr117745.c: New test. (cherry picked from commit 958f0025f41d8bd9812e4da91a72b1ad79496e5b)
