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de38d64ad2
With GCC 6.4 and 6.5 (at least), unit tests that use
gdbsupport/valid-expr.h's CHECK_VALID fail to compile, with:
In file included from src/gdb/unittests/offset-type-selftests.c:24:0:
src/gdb/unittests/offset-type-selftests.c: In substitution of 'template<class Expected, template<class ...> class Op, class ... Args> using is_detected_exact = std::is_same<Expected, typename gdb::detection_detail::detector<gdb::nonesuch, void, Op, Args ...>::type> [with Expected = selftests::offset_type::off_A&; Op = selftests::offset_type::check_valid_expr75::archetype; Args = {selftests::offset_type::off_A, selftests::offset_type::off_B}]':
src/gdb/unittests/offset-type-selftests.c:75:1: required from here
src/gdb/../gdbsupport/valid-expr.h:65:20: error: type/value mismatch at argument 2 in template parameter list for 'template<class Expected, template<class ...> class Op, class ... Args> using is_detected_exact = std::is_same<Expected, typename gdb::detection_detail::detector<gdb::nonesuch, void, Op, Args ...>::type>'
archetype, TYPES>::value == VALID, \
^
The important part is the "error: type/value mismatch" error. Seems
like that GCC doesn't understand that archetype is an alias template,
and is being strict in requiring a template class.
The fix here is then to make archetype a template class, to pacify
GCC. The resulting code looks like this:
template <TYPENAMES, typename = decltype (EXPR)>
struct archetype
{
};
static_assert (gdb::is_detected_exact<archetype<TYPES, EXPR_TYPE>,
archetype, TYPES>::value == VALID, "");
is_detected_exact<Expected, Op, Args> checks whether Op<Args> is type
Expected:
- For Expected, we pass the explicit EXPR_TYPE, overriding the
default parameter type of archetype.
- For Args we don't pass the last template parameter, so archtype
defaults to the EXPR's decltype.
So in essence, we're really checking whether EXPR_TYPE is the same as
decltype(EXPR).
We need to do the decltype in a template context in order to trigger
SFINAE instead of failing to compile.
The hunk in unittests/enum-flags-selftests.c becomes necessary,
because unlike with the current alias template version, this new
version makes GCC trigger -Wenum-compare warnings as well:
src/gdb/unittests/enum-flags-selftests.c:328:33: error: comparison between 'enum selftests::enum_flags_tests::RE' and 'enum selftests::enum_flags_tests::RE2' [-Werror=enum-compare]
CHECK_VALID (true, bool, RE () != RE2 ())
^
src/gdb/../gdbsupport/valid-expr.h:61:45: note: in definition of macro 'CHECK_VALID_EXPR_INT'
template <TYPENAMES, typename = decltype (EXPR)> \
^
Build-tested with:
- GCC {4.8.5, 6.4, 6.5, 7.3.1, 9.3.0, 11.0.0-20200910}
- Clang 10.0.0
gdbsupport/ChangeLog:
* valid-expr.h (CHECK_VALID_EXPR_INT): Make archetype a template
class instead of an alias template and adjust static_assert.
gdb/ChangeLog:
* unittests/enum-flags-selftests.c: Check whether __GNUC__ is
defined before using '#pragma GCC diagnostic' instead of checking
__clang__.
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| .. | ||
| .dir-locals.el | ||
| .gitattributes | ||
| acinclude.m4 | ||
| aclocal.m4 | ||
| agent.cc | ||
| agent.h | ||
| alt-stack.h | ||
| array-view.h | ||
| ax.def | ||
| block-signals.h | ||
| break-common.h | ||
| btrace-common.cc | ||
| btrace-common.h | ||
| buffer.cc | ||
| buffer.h | ||
| byte-vector.h | ||
| ChangeLog | ||
| check-defines.el | ||
| cleanups.cc | ||
| cleanups.h | ||
| common-debug.cc | ||
| common-debug.h | ||
| common-defs.h | ||
| common-exceptions.cc | ||
| common-exceptions.h | ||
| common-gdbthread.h | ||
| common-inferior.cc | ||
| common-inferior.h | ||
| common-regcache.cc | ||
| common-regcache.h | ||
| common-types.h | ||
| common-utils.cc | ||
| common-utils.h | ||
| common.m4 | ||
| config.in | ||
| configure | ||
| configure.ac | ||
| create-version.sh | ||
| def-vector.h | ||
| default-init-alloc.h | ||
| eintr.h | ||
| enum-flags.h | ||
| environ.cc | ||
| environ.h | ||
| errors.cc | ||
| errors.h | ||
| event-loop.cc | ||
| event-loop.h | ||
| fileio.cc | ||
| fileio.h | ||
| filestuff.cc | ||
| filestuff.h | ||
| filtered-iterator.h | ||
| format.cc | ||
| format.h | ||
| forward-scope-exit.h | ||
| function-view.h | ||
| gdb_assert.h | ||
| gdb_binary_search.h | ||
| gdb_locale.h | ||
| gdb_optional.h | ||
| gdb_proc_service.h | ||
| gdb_ref_ptr.h | ||
| gdb_select.h | ||
| gdb_setjmp.h | ||
| gdb_signals.h | ||
| gdb_splay_tree.h | ||
| gdb_string_view.h | ||
| gdb_string_view.tcc | ||
| gdb_sys_time.h | ||
| gdb_tilde_expand.cc | ||
| gdb_tilde_expand.h | ||
| gdb_unique_ptr.h | ||
| gdb_unlinker.h | ||
| gdb_vecs.cc | ||
| gdb_vecs.h | ||
| gdb_wait.cc | ||
| gdb_wait.h | ||
| gdb-dlfcn.cc | ||
| gdb-dlfcn.h | ||
| gdb-safe-ctype.h | ||
| gdb-sigmask.h | ||
| hash_enum.h | ||
| host-defs.h | ||
| job-control.cc | ||
| job-control.h | ||
| Makefile.am | ||
| Makefile.in | ||
| netstuff.cc | ||
| netstuff.h | ||
| new-op.cc | ||
| next-iterator.h | ||
| observable.h | ||
| offset-type.h | ||
| parallel-for.h | ||
| pathstuff.cc | ||
| pathstuff.h | ||
| poison.h | ||
| preprocessor.h | ||
| print-utils.cc | ||
| print-utils.h | ||
| ptid.cc | ||
| ptid.h | ||
| README | ||
| refcounted-object.h | ||
| rsp-low.cc | ||
| rsp-low.h | ||
| run-time-clock.cc | ||
| run-time-clock.h | ||
| safe-iterator.h | ||
| safe-strerror.cc | ||
| scope-exit.h | ||
| scoped_fd.h | ||
| scoped_mmap.cc | ||
| scoped_mmap.h | ||
| scoped_restore.h | ||
| selftest.cc | ||
| selftest.h | ||
| selftest.m4 | ||
| signals-state-save-restore.cc | ||
| signals-state-save-restore.h | ||
| signals.cc | ||
| symbol.h | ||
| tdesc.cc | ||
| tdesc.h | ||
| thread-pool.cc | ||
| thread-pool.h | ||
| traits.h | ||
| underlying.h | ||
| valid-expr.h | ||
| version.h | ||
| warning.m4 | ||
| x86-xstate.h | ||
| xml-utils.cc | ||
| xml-utils.h | ||
This is a helper library that is used by gdb and gdbserver. To send patches, follow the gdb patch submission instructions in ../gdb/CONTRIBUTE. For maintainers, see ../gdb/MAINTAINERS.