[libcxx-commits] [libcxx] [libc++][modules] Adds std.compat module. (PR #71438)

[Louis Dionne via libcxx-commits]

================
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+# ===----------------------------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# ===----------------------------------------------------------------------===##
+
+from libcxx.header_information import module_headers
+from libcxx.header_information import header_restrictions
+
+### SkipDeclarations
+
+# Ignore several declarations found in the includes.
+#
+# Part of these items are bugs other are not yet implemented features.
+SkipDeclarations = dict()
+
+# See comment in the header.
+SkipDeclarations["cuchar"] = ["std::mbstate_t", "std::size_t"]
+
+# Not in the synopsis.
+SkipDeclarations["cwchar"] = ["std::FILE"]
+
+# The operators are added for private types like __iom_t10.
+SkipDeclarations["iomanip"] = ["std::operator<<", "std::operator>>"]
+
+SkipDeclarations["iosfwd"] = ["std::ios_base", "std::vector"]
+
+# This header also provides declarations in the namespace that might be
+# an error.
+SkipDeclarations["filesystem"] = [
+    "std::filesystem::operator==",
+    "std::filesystem::operator!=",
+]
+
+# This is a specialization for a private type
+SkipDeclarations["iterator"] = ["std::pointer_traits"]
+
+# TODO MODULES
+# This definition is declared in string and defined in istream
+# This declaration should be part of string
+SkipDeclarations["istream"] = ["std::getline"]
+
+# P1614 (at many places) and LWG3519 too.
+SkipDeclarations["random"] = [
+    "std::operator!=",
+    # LWG3519 makes these hidden friends.
+    # Note the older versions had the requirement of these operations but not in
+    # the synopsis.
+    "std::operator<<",
+    "std::operator>>",
+    "std::operator==",
+]
+
+# Declared in the forward header since std::string uses std::allocator
+SkipDeclarations["string"] = ["std::allocator"]
+# TODO MODULES remove zombie names
+# https://libcxx.llvm.org/Status/Cxx20.html#note-p0619
+SkipDeclarations["memory"] = [
+    "std::return_temporary_buffer",
+    "std::get_temporary_buffer",
+]
+
+# TODO MODULES this should be part of ios instead
+SkipDeclarations["streambuf"] = ["std::basic_ios"]
+
+# include/__type_traits/is_swappable.h
+SkipDeclarations["type_traits"] = [
+    "std::swap",
+    # TODO MODULES gotten through __functional/unwrap_ref.h
+    "std::reference_wrapper",
+]
+
+### ExtraDeclarations
+
+# Add declarations in headers.
+#
+# Some headers have their defines in a different header, which may have
+# additional declarations.
+ExtraDeclarations = dict()
+# This declaration is in the ostream header.
+ExtraDeclarations["system_error"] = ["std::operator<<"]
+
+### ExtraHeader
+
+# Adds extra headers file to scan
+#
+# Some C++ headers in libc++ are stored in multiple physical files. There is a
+# pattern to find these files. However there are some exceptions these are
+# listed here.
+ExtraHeader = dict()
+# locale has a file and not a subdirectory
+ExtraHeader["locale"] = "v1/__locale$"
+ExtraHeader["thread"] = "v1/__threading_support$"
+ExtraHeader["ranges"] = "v1/__fwd/subrange.h$"
+
+# The extra header is needed since two headers are required to provide the
+# same definition.
+ExtraHeader["functional"] = "v1/__compare/compare_three_way.h$"
+
+
+# newline needs to be escaped for the module partition output.
+nl = "\\\\n"
+
+
+class module_test_generator:
+    def __init__(
+        self,
+        tmp_prefix,
+        module_path,
+        clang_tidy,
+        clang_tidy_plugin,
+        compiler,
+        compiler_flags,
+    ):
+        self.tmp_prefix = tmp_prefix
+        self.module_path = module_path
+        self.clang_tidy = clang_tidy
+        self.clang_tidy_plugin = clang_tidy_plugin
+        self.compiler = compiler
+        self.compiler_flags = compiler_flags
+
+    def write_lit_configuration(self):
+        print(
+            f"""\
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-has-no-std-modules
+// UNSUPPORTED: clang-modules-build
+
+// REQUIRES: has-clang-tidy
+
+// The GCC compiler flags are not always compatible with clang-tidy.
+// UNSUPPORTED: gcc
+
+// RUN: echo -n > {self.tmp_prefix}.all_partitions
+"""
+        )
+
+    def process_module_partition(self, header, is_c_header):
+        # Some headers cannot be included when a libc++ feature is disabled.
+        # In that case include the header conditionally. The header __config
+        # ensures the libc++ feature macros are available.
+        if header in header_restrictions:
+            include = (
+                f"#include <__config>{nl}"
+                f"#if {header_restrictions[header]}{nl}"
+                f"#  include <{header}>{nl}"
+                f"#endif{nl}"
+            )
+        elif header == "chrono":
+            # When localization is disabled the header string is not included.
+            # When string is included chrono's operator""s is a named declaration
+            #   using std::chrono_literals::operator""s;
+            # else it is a named declaration
+            #   using std::operator""s;
+            # TODO MODULES investigate why
+            include = f"#include <string>{nl}#include <chrono>{nl}"
+        else:
+            include = f"#include <{header}>{nl}"
+
+        module_files = f'#include \\"%{{module}}/std/{header}.inc\\"{nl}'
+        if is_c_header:
+            module_files += f'#include \\"%{{module}}/std.compat/{header}.inc\\"{nl}'
----------------
ldionne wrote:

```suggestion
            module_files += f'#include \\"{self.module_path}/std.compat/{header}.inc\\"{nl}'
```

https://github.com/llvm/llvm-project/pull/71438