https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66290
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Lewis Hyatt <lhy...@gcc.gnu.org>: https://gcc.gnu.org/g:b04c399e258e686dddad879bf7e27d9e28fd6fde commit r13-1903-gb04c399e258e686dddad879bf7e27d9e28fd6fde Author: Lewis Hyatt <lhy...@gmail.com> Date: Tue Jul 12 09:47:47 2022 -0400 c++: Fix location for -Wunused-macros [PR66290] In C++, since all tokens are lexed from libcpp up front, diagnostics generated by libcpp after lexing has completed do not get a valid location from libcpp (rather, libcpp thinks they all pertain to the end of the file.) This has long been addressed using the global variable "done_lexing", which the C++ frontend sets at the appropriate time; when done_lexing is true, then c_cpp_diagnostic(), which outputs libcpp's diagnostics, uses input_location instead of the wrong libcpp location. The C++ frontend arranges that input_location will point to the token it is currently processing, so this generally works fine. However, there is one exception currently, which is -Wunused-macros. This gets generated at the end of processing in cpp_finish (), since we need to wait until then to determine whether a macro was eventually used or not. But the locations it passes to c_cpp_diagnostic () were remembered from the original lexing and hence they should not be overridden with input_location, which is now the one incorrectly pointing to the end of the file. Fixed by setting done_lexing=false again just prior to calling cpp_finish (). I also renamed the variable from done_lexing to "override_libcpp_locations", since it's now not strictly about lexing anymore. There is no new testcase with this patch, since we already had an xfailed testcase which is now fixed. gcc/c-family/ChangeLog: PR c++/66290 * c-common.h: Rename global done_lexing to override_libcpp_locations. * c-common.cc (c_cpp_diagnostic): Likewise. * c-opts.cc (c_common_finish): Set override_libcpp_locations (formerly done_lexing) immediately prior to calling cpp_finish (). gcc/cp/ChangeLog: PR c++/66290 * parser.cc (cp_lexer_new_main): Rename global done_lexing to override_libcpp_locations. gcc/testsuite/ChangeLog: PR c++/66290 * c-c++-common/pragma-diag-15.c: Remove xfail for C++.
