[libc++] Remove _LIBCXX_MODULES_BUILD and ext/ headers from header tests

[• Quuxplusone]

It occurred to me this morning that there's yet another option for dealing with <ext/foo>. We could add them to the modulemap as textual headers, and then (to avoid the -Wprivate-header diagnostic on <__algorithm/is_permutation.h>) change them back to including all of <algorithm> instead of just <__algorithm/is_permutation.h>. <algorithm> is a public header, so it would be fine to include from a textual header. Then we wouldn't even need to skip their tests in the modules build.

But I don't object to this direction now and maybe someone'll investigate that direction later. I think the stakes here are low.

[philnik]

In D120896#3357149, @Quuxplusone wrote:

It occurred to me this morning that there's yet another option for dealing with <ext/foo>. We could add them to the modulemap as textual headers, and then (to avoid the -Wprivate-header diagnostic on <__algorithm/is_permutation.h>) change them back to including all of <algorithm> instead of just <__algorithm/is_permutation.h>. <algorithm> is a public header, so it would be fine to include from a textual header. Then we wouldn't even need to skip their tests in the modules build.

But I don't object to this direction now and maybe someone'll investigate that direction later. I think the stakes here are low.

I'd want to avoid that, because after removing <experimental/algorithm> we could mechanically check for #include <algorithm> to make sure no one's going to include it directly again.

[• Quuxplusone]

In D120896#3357193, @philnik wrote:

I'd want to avoid that, because after removing <experimental/algorithm> we could mechanically check for #include <algorithm> to make sure no one's going to include it directly again.

I support that mechanical-check idea (lint_headers.sh.py :)) but it'd be 100% trivial to just exclude ext/hash_set from that particular check. If we go in @ldionne's suggested direction, of decoupling ext/ from libc++ proper and moving it into a third-party directory where it is no longer considered part of libc++, we should make it stop including detail headers anyway.

libcxx/test/libcxx/clang_tidy.sh.cpp

 #    include <experimental/string>
 #    include <experimental/type_traits>
 #    include <experimental/unordered_map>
 #    include <experimental/unordered_set>
 #    include <experimental/utility>
 #    include <experimental/vector>
 #endif // __cplusplus >= 201103L
 
-// extended headers
-#ifndef _LIBCXX_MODULES_BUILD
-#    include <ext/hash_map>
-#    include <ext/hash_set>
-#endif
-
 // clang-format on
 
 ////////////////////////////////////////////////////////////////////////////////
 // END-GENERATED-HEADERS
 ////////////////////////////////////////////////////////////////////////////////

libcxx/test/libcxx/double_include.sh.cpp

 #    include <experimental/string>
 #    include <experimental/type_traits>
 #    include <experimental/unordered_map>
 #    include <experimental/unordered_set>
 #    include <experimental/utility>
 #    include <experimental/vector>
 #endif // __cplusplus >= 201103L
 
-// extended headers
-#ifndef _LIBCXX_MODULES_BUILD
-#    include <ext/hash_map>
-#    include <ext/hash_set>
-#endif
-
 // clang-format on
 
 ////////////////////////////////////////////////////////////////////////////////
 // END-GENERATED-HEADERS
 ////////////////////////////////////////////////////////////////////////////////
 
 #if defined(WITH_MAIN)
 int main(int, char**) { return 0; }
 #endif

libcxx/test/libcxx/min_max_macros.compile.pass.cpp

 #    include <experimental/unordered_set>
 TEST_MACROS();
 #    include <experimental/utility>
 TEST_MACROS();
 #    include <experimental/vector>
 TEST_MACROS();
 #endif // __cplusplus >= 201103L
 
-// extended headers
-#ifndef _LIBCXX_MODULES_BUILD
-#    include <ext/hash_map>
-TEST_MACROS();
-#    include <ext/hash_set>
-TEST_MACROS();
-#endif
-
 // clang-format on
 
 ////////////////////////////////////////////////////////////////////////////////
 // END-GENERATED-HEADERS
 ////////////////////////////////////////////////////////////////////////////////

libcxx/test/libcxx/nasty_macros.compile.pass.cpp

 #    include <experimental/string>
 #    include <experimental/type_traits>
 #    include <experimental/unordered_map>
 #    include <experimental/unordered_set>
 #    include <experimental/utility>
 #    include <experimental/vector>
 #endif // __cplusplus >= 201103L
 
-// extended headers
-#ifndef _LIBCXX_MODULES_BUILD
-#    include <ext/hash_map>
-#    include <ext/hash_set>
-#endif
-
 // clang-format on
 
 ////////////////////////////////////////////////////////////////////////////////
 // END-GENERATED-HEADERS
 ////////////////////////////////////////////////////////////////////////////////

libcxx/test/libcxx/no_assert_include.compile.pass.cpp

 #    include <experimental/string>
 #    include <experimental/type_traits>
 #    include <experimental/unordered_map>
 #    include <experimental/unordered_set>
 #    include <experimental/utility>
 #    include <experimental/vector>
 #endif // __cplusplus >= 201103L
 
-// extended headers
-#ifndef _LIBCXX_MODULES_BUILD
-#    include <ext/hash_map>
-#    include <ext/hash_set>
-#endif
-
 // clang-format on
 
 ////////////////////////////////////////////////////////////////////////////////
 // END-GENERATED-HEADERS
 ////////////////////////////////////////////////////////////////////////////////
 
 #ifdef assert
 #error "Do not include cassert or assert.h in standard header files"
 #endif

libcxx/utils/generate_header_tests.py

 headers_template = """\
 // Top level headers
 {top_level_headers}
 
 // experimental headers
 #if __cplusplus >= 201103L
 {experimental_headers}
 #endif // __cplusplus >= 201103L
-
-// extended headers
-#ifndef _LIBCXX_MODULES_BUILD
-{extended_headers}
-#endif
 """
 
 
 def should_keep_header(p, exclusions=None):
     if os.path.isdir(p):
         return False
 
     if exclusions:
def produce_test(test_filename, exclusions=None, post_include=None):
     test_str = headers_template.format(
         top_level_headers=produce_top_level_headers(
             post_include=post_include,
             exclusions=exclusions,
         ),
         experimental_headers=produce_experimental_headers(
             post_include=post_include,
         ),
-        extended_headers=produce_extended_headers(
-            post_include=post_include,
-        ),
     )
 
     replace_generated_headers(os.path.join(
         libcxx_test_path, test_filename), test_str)
 
 
 def main():
     produce_test('clang_tidy.sh.cpp')
     produce_test('double_include.sh.cpp')
     produce_test('min_max_macros.compile.pass.cpp', post_include='TEST_MACROS();')
     produce_test('nasty_macros.compile.pass.cpp')
     produce_test('no_assert_include.compile.pass.cpp', exclusions=['cassert'])
 
 
 if __name__ == '__main__':
     main()

libcxx/utils/libcxx/test/params.py

Parameter(name='std', choices=_allStandards, type=str,
             ]),
 
   Parameter(name='enable_modules', choices=[True, False], type=bool, default=False,
             help="Whether to build the test suite with Clang modules enabled.",
             actions=lambda modules: [
               AddFeature('modules-build'),
               AddCompileFlag('-fmodules'),
               AddCompileFlag('-fcxx-modules'), # AppleClang disregards -fmodules entirely when compiling C++. This enables modules for C++.
-              AddCompileFlag('-D_LIBCXX_MODULES_BUILD') # Needed to exclude headers that are not supported in a modules build
             ] if modules else []),
 
   Parameter(name='enable_exceptions', choices=[True, False], type=bool, default=True,
             help="Whether to enable exceptions when compiling the test suite.",
             actions=lambda exceptions: [] if exceptions else [
               AddFeature('no-exceptions'),
               AddCompileFlag('-fno-exceptions')
             ]),