[libc++] Fix modules builds when features are removed

When some headers are not available because we removed features like localization or threads, the compiler should not try to include these headers when building modules. To avoid that from happening, add a requires-declaration that is never satisfied when the configuration in use doesn't support a header. rdar://93777687 Differential Revision: https://reviews.llvm.org/D127127
llvm · Jun 8, 2022 · 0e9a01d · 0e9a01d
1 parent 6504b15
commit 0e9a01d
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Showing 10 changed files with 68 additions and 23 deletions.
diff --git a/libcxx/docs/Contributing.rst b/libcxx/docs/Contributing.rst
@@ -37,7 +37,7 @@ sure you don't forget anything:
 - Did you mark all functions and type declarations with the :ref:`proper visibility macro <visibility-macros>`?
 - If you added a header:
 
-  - Did you add it to ``include/module.modulemap``?
+  - Did you add it to ``include/module.modulemap.in``?
   - Did you add it to ``include/CMakeLists.txt``?
   - If it's a public header, did you add a test under ``test/libcxx`` that the new header defines ``_LIBCPP_VERSION``? See ``test/libcxx/algorithms/version.pass.cpp`` for an example. NOTE: This should be automated.
   - If it's a public header, did you update ``utils/generate_header_inclusion_tests.py``?

diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
@@ -618,7 +618,6 @@ set(files
   map
   math.h
   memory
-  module.modulemap
   mutex
   new
   numbers
@@ -669,9 +668,17 @@ set(files
   wctype.h
   )
 
+foreach(feature LIBCXX_ENABLE_FILESYSTEM LIBCXX_ENABLE_LOCALIZATION LIBCXX_ENABLE_THREADS LIBCXX_ENABLE_WIDE_CHARACTERS)
+  if (NOT ${${feature}})
+    set(requires_${feature} "requires LIBCXX_CONFIGURED_WITHOUT_SUPPORT_FOR_THIS_HEADER")
+  endif()
+endforeach()
+
 configure_file("__config_site.in" "${LIBCXX_GENERATED_INCLUDE_TARGET_DIR}/__config_site" @ONLY)
+configure_file("module.modulemap.in" "${LIBCXX_GENERATED_INCLUDE_DIR}/module.modulemap" @ONLY)
 
-set(_all_includes "${LIBCXX_GENERATED_INCLUDE_TARGET_DIR}/__config_site")
+set(_all_includes "${LIBCXX_GENERATED_INCLUDE_TARGET_DIR}/__config_site"
+                  "${LIBCXX_GENERATED_INCLUDE_DIR}/module.modulemap")
 foreach(f ${files})
   set(src "${CMAKE_CURRENT_SOURCE_DIR}/${f}")
   set(dst "${LIBCXX_GENERATED_INCLUDE_DIR}/${f}")

diff --git a/libcxx/include/csignal b/libcxx/include/csignal
@@ -41,7 +41,10 @@ int raise(int sig);
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
-#include <signal.h>
+
+#if __has_include(<signal.h>)
+# include <signal.h>
+#endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header

diff --git a/libcxx/include/module.modulemap → libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap → libcxx/include/module.modulemap.in
@@ -38,6 +38,7 @@ module std [system] {
     // <iso646.h> provided by compiler.
     // <limits.h> provided by compiler or C library.
     module locale_h {
+      @requires_LIBCXX_ENABLE_LOCALIZATION@
       header "locale.h"
       export *
     }
@@ -50,6 +51,7 @@ module std [system] {
       export *
     }
     module stdatomic_h {
+      @requires_LIBCXX_ENABLE_THREADS@
       requires cplusplus23
       header "stdatomic.h"
       export *
@@ -90,11 +92,13 @@ module std [system] {
     }
     // <time.h> provided by C library.
     module wchar_h {
+      @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
       // <wchar.h>'s __need_* macros require textual inclusion.
       textual header "wchar.h"
       export *
     }
     module wctype_h {
+      @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
       header "wctype.h"
       export *
     }
@@ -155,6 +159,7 @@ module std [system] {
       export *
     }
     module clocale {
+      @requires_LIBCXX_ENABLE_LOCALIZATION@
       header "clocale"
       export *
     }
@@ -215,11 +220,13 @@ module std [system] {
       export *
     }
     module cwchar {
+      @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
       header "cwchar"
       export depr.stdio_h
       export *
     }
     module cwctype {
+      @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
       header "cwctype"
       export *
     }
@@ -382,6 +389,7 @@ module std [system] {
     export *
   }
   module barrier {
+    @requires_LIBCXX_ENABLE_THREADS@
     header "barrier"
     export *
   }
@@ -425,7 +433,11 @@ module std [system] {
       module duration              { private header "__chrono/duration.h" }
       module file_clock            { private header "__chrono/file_clock.h" }
       module hh_mm_ss              { private header "__chrono/hh_mm_ss.h" }
-      module high_resolution_clock { private header "__chrono/high_resolution_clock.h" }
+      module high_resolution_clock {
+        private header "__chrono/high_resolution_clock.h"
+        export steady_clock
+        export system_clock
+      }
       module literals              { private header "__chrono/literals.h" }
       module month                 { private header "__chrono/month.h" }
       module month_weekday         { private header "__chrono/month_weekday.h" }
@@ -441,6 +453,7 @@ module std [system] {
     }
   }
   module codecvt {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "codecvt"
     export *
   }
@@ -528,6 +541,7 @@ module std [system] {
     export *
   }
   module filesystem {
+    @requires_LIBCXX_ENABLE_FILESYSTEM@
     header "filesystem"
     export *
 
@@ -588,6 +602,7 @@ module std [system] {
     export *
   }
   module fstream {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "fstream"
     export *
   }
@@ -626,6 +641,7 @@ module std [system] {
     }
   }
   module future {
+    @requires_LIBCXX_ENABLE_THREADS@
     header "future"
     export *
   }
@@ -634,10 +650,12 @@ module std [system] {
     export *
   }
   module iomanip {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "iomanip"
     export *
   }
   module ios {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "ios"
     export iosfwd
     export *
@@ -651,6 +669,7 @@ module std [system] {
     export *
   }
   module iostream {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "iostream"
     export ios
     export streambuf
@@ -659,6 +678,7 @@ module std [system] {
     export *
   }
   module istream {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "istream"
     // FIXME: should re-export ios, streambuf?
     export *
@@ -711,6 +731,7 @@ module std [system] {
     }
   }
   module latch {
+    @requires_LIBCXX_ENABLE_THREADS@
     header "latch"
     export *
   }
@@ -724,6 +745,7 @@ module std [system] {
     export *
   }
   module locale {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "locale"
     export *
   }
@@ -761,6 +783,7 @@ module std [system] {
     }
   }
   module mutex {
+    @requires_LIBCXX_ENABLE_THREADS@
     header "mutex"
     export *
   }
@@ -797,6 +820,7 @@ module std [system] {
     export *
   }
   module ostream {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "ostream"
     // FIXME: should re-export ios, streambuf?
     export *
@@ -909,6 +933,7 @@ module std [system] {
     export *
   }
   module regex {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "regex"
     export initializer_list
     export *
@@ -918,6 +943,7 @@ module std [system] {
     export *
   }
   module semaphore {
+    @requires_LIBCXX_ENABLE_THREADS@
     header "semaphore"
     export *
   }
@@ -927,6 +953,7 @@ module std [system] {
     export *
   }
   module shared_mutex {
+    @requires_LIBCXX_ENABLE_THREADS@
     header "shared_mutex"
     export version
   }
@@ -937,6 +964,7 @@ module std [system] {
     module span_fwd { private header "__fwd/span.h" }
   }
   module sstream {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "sstream"
     // FIXME: should re-export istream, ostream, ios, streambuf, string?
     export *
@@ -951,6 +979,7 @@ module std [system] {
     export *
   }
   module streambuf {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "streambuf"
     export *
   }
@@ -969,6 +998,7 @@ module std [system] {
     module string_view_fwd { private header "__fwd/string_view.h" }
   }
   module strstream {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
     header "strstream"
     export *
   }
@@ -977,6 +1007,7 @@ module std [system] {
     export *
   }
   module thread {
+    @requires_LIBCXX_ENABLE_THREADS@
     header "thread"
     export *
 
@@ -1118,7 +1149,6 @@ module std [system] {
     export *
   }
 
-  // __config not modularised due to a bug in Clang
   // FIXME: These should be private.
   module __assert            {         header "__assert"            export * }
   module __availability      { private header "__availability"      export * }
@@ -1127,12 +1157,18 @@ module std [system] {
   module __debug             {         header "__debug"             export * }
   module __errc              { private header "__errc"              export * }
   module __hash_table        {         header "__hash_table"        export * }
-  module __locale            { private header "__locale"            export * }
+  module __locale            {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
+    private header "__locale" export *
+  }
   module __mbstate_t         { private header "__mbstate_t.h"       export * }
   module __mutex_base        { private header "__mutex_base"        export * }
   module __node_handle       { private header "__node_handle"       export * }
   module __split_buffer      { private header "__split_buffer"      export * }
-  module __std_stream        { private header "__std_stream"        export * }
+  module __std_stream        {
+    @requires_LIBCXX_ENABLE_LOCALIZATION@
+    private header "__std_stream" export *
+  }
   module __string            { private header "__string"            export * }
   module __threading_support {         header "__threading_support" export * }
   module __tree              {         header "__tree"              export * }
@@ -1184,6 +1220,7 @@ module std [system] {
       export *
     }
     module regex {
+      @requires_LIBCXX_ENABLE_LOCALIZATION@
       header "experimental/regex"
       export *
     }

diff --git a/libcxx/test/libcxx/lint/lint_headers.sh.py b/libcxx/test/libcxx/lint/lint_headers.sh.py
@@ -11,7 +11,7 @@
 def exclude_from_consideration(path):
     return (
         path.endswith('.txt') or
-        path.endswith('.modulemap') or
+        path.endswith('.modulemap.in') or
         os.path.basename(path) == '__config' or
         os.path.basename(path) == '__config_site.in' or
         not os.path.isfile(path)

diff --git a/libcxx/test/libcxx/lint/lint_modulemap.sh.py b/libcxx/test/libcxx/lint/lint_modulemap.sh.py
@@ -1,6 +1,6 @@
 # RUN: %{python} %s
 
-# Verify that each list of private submodules in libcxx/include/module.modulemap
+# Verify that each list of private submodules in libcxx/include/module.modulemap.in
 # is maintained in alphabetical order.
 
 import os
@@ -10,7 +10,7 @@
 if __name__ == '__main__':
     libcxx_test_libcxx_lint = os.path.dirname(os.path.abspath(__file__))
     libcxx = os.path.abspath(os.path.join(libcxx_test_libcxx_lint, '../../..'))
-    modulemap_name = os.path.join(libcxx, 'include/module.modulemap')
+    modulemap_name = os.path.join(libcxx, 'include/module.modulemap.in')
     assert os.path.isfile(modulemap_name)
 
     okay = True
@@ -31,12 +31,12 @@
                     pass
                 else:
                     okay = False
-                    print("LINE DOESN'T MATCH REGEX in libcxx/include/module.modulemap!")
+                    print("LINE DOESN'T MATCH REGEX in libcxx/include/module.modulemap.in!")
                     print(line)
                 # Check that these lines are alphabetized.
                 if (prevline is not None) and (line < prevline):
                     okay = False
-                    print('LINES OUT OF ORDER in libcxx/include/module.modulemap!')
+                    print('LINES OUT OF ORDER in libcxx/include/module.modulemap.in!')
                     print(prevline)
                     print(line)
                 prevline = line

diff --git a/libcxx/test/libcxx/modules_include.sh.cpp b/libcxx/test/libcxx/modules_include.sh.cpp
@@ -19,10 +19,6 @@
 // The Windows headers don't appear to be compatible with modules
 // UNSUPPORTED: windows
 
-// TODO: Some headers produce errors when we include them and the library has been
-//       configured without support for them, which breaks the modules build.
-// UNSUPPORTED: no-localization, no-filesystem, no-threads, no-wide-characters
-
 // Prevent <ext/hash_map> from generating deprecated warnings for this test.
 #if defined(__DEPRECATED)
 #    undef __DEPRECATED

diff --git a/libcxx/utils/generate_header_tests.py b/libcxx/utils/generate_header_tests.py
@@ -113,7 +113,7 @@ def produce(test_file, variables):
 
 def is_header(file):
     """Returns whether the given file is a header (i.e. not a directory or the modulemap file)."""
-    return not file.is_dir() and not file.name == 'module.modulemap'
+    return not file.is_dir() and not file.name == 'module.modulemap.in'
 
 def main():
     monorepo_root = pathlib.Path(os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))))

diff --git a/libcxx/utils/libcxx/test/dsl.py b/libcxx/utils/libcxx/test/dsl.py
@@ -276,9 +276,11 @@ def compilerMacros(config, flags=''):
   """
   with _makeConfigTest(config) as test:
     with open(test.getSourcePath(), 'w') as sourceFile:
-      # Make sure files like <__config> are included, since they can define
-      # additional macros.
-      sourceFile.write("#include <stddef.h>")
+      sourceFile.write("""
+      #if __has_include(<__config_site>)
+      #  include <__config_site>
+      #endif
+      """)
     unparsedOutput, err, exitCode, _ = _executeScriptInternal(test, [
       "%{{cxx}} %s -dM -E %{{flags}} %{{compile_flags}} {}".format(flags)
     ])