[2/5] support C++20 Modules, add C++20 modules tools

scripts/bootstrap/compile.sh

@@ -281,6 +281,10 @@ EOF
   link_file "${PWD}/tools/cpp/runfiles/BUILD.tools" \
       "${BAZEL_TOOLS_REPO}/tools/cpp/runfiles/BUILD"
 
+  # Create @bazel_tools//tools/cpp/modules_tools
+  mkdir -p ${BAZEL_TOOLS_REPO}/tools/cpp/modules_tools
+  link_file "${PWD}/tools/cpp/modules_tools/BUILD.tools" "${BAZEL_TOOLS_REPO}/tools/cpp/modules_tools/BUILD"
+
   # Create @bazel_tools//tools/sh
   mkdir -p ${BAZEL_TOOLS_REPO}/tools/sh
   link_file "${PWD}/tools/sh/sh_configure.bzl" "${BAZEL_TOOLS_REPO}/tools/sh/sh_configure.bzl"

src/main/starlark/builtins_bzl/common/cc/cc_toolchain.bzl

@@ -98,6 +98,8 @@ def _attributes(ctx):
         objcopy_files = _files(ctx, "objcopy_files"),
         link_dynamic_library_tool = ctx.file._link_dynamic_library_tool,
         grep_includes = grep_includes,
+        aggregate_ddi = _single_file(ctx, "_aggregate_ddi"),
+        generate_modmap = _single_file(ctx, "_generate_modmap"),
         module_map = ctx.attr.module_map,
         as_files = _files(ctx, "as_files"),
         ar_files = _files(ctx, "ar_files"),
@@ -342,5 +344,5 @@ The label of the rule providing <code>cc_toolchain_config_info</code>.""",
             default = semantics.BUILD_INFO_TRANLATOR_LABEL,
             providers = [OutputGroupInfo],
         ),
-    },
+    } | semantics.cpp_modules_tools(),
 )

src/main/starlark/builtins_bzl/common/cc/cc_toolchain_info.bzl

@@ -95,7 +95,9 @@ def _create_cc_toolchain_info(
         grep_includes,
         allowlist_for_layering_check,
         build_info_files,
-        objcopy_files):
+        objcopy_files,
+        aggregate_ddi,
+        generate_modmap):
     cc_toolchain_info = dict(
         needs_pic_for_dynamic_libraries = (lambda *, feature_configuration: True) if cpp_configuration.force_pic() else _needs_pic_for_dynamic_libraries,
         built_in_include_directories = built_in_include_directories,
@@ -157,6 +159,8 @@ def _create_cc_toolchain_info(
         _allowlist_for_layering_check = allowlist_for_layering_check,
         _cc_info = cc_info,
         _objcopy_files = objcopy_files,
+        _aggregate_ddi = aggregate_ddi,
+        _generate_modmap = generate_modmap,
     )
     return cc_toolchain_info
 
@@ -250,6 +254,8 @@ CcToolchainInfo, _ = provider(
         "_allowlist_for_layering_check": "INTERNAL API, DO NOT USE!",
         "_cc_info": "INTERNAL API, DO NOT USE!",
         "_objcopy_files": "INTERNAL API, DO NOT USE!",
+        "_aggregate_ddi": "INTERNAL API, DO NOT USE!",
+        "_generate_modmap": "INTERNAL API, DO NOT USE!",
     },
     init = _create_cc_toolchain_info,
 )

src/main/starlark/builtins_bzl/common/cc/cc_toolchain_provider_helper.bzl

@@ -297,6 +297,8 @@ def get_cc_toolchain_provider(ctx, attributes):
         supports_header_parsing = attributes.supports_header_parsing,
         link_dynamic_library_tool = attributes.link_dynamic_library_tool,
         grep_includes = attributes.grep_includes,
+        aggregate_ddi = attributes.aggregate_ddi,
+        generate_modmap = attributes.generate_modmap,
         allowlist_for_layering_check = attributes.allowlist_for_layering_check,
         build_info_files = attributes.build_info_files,
         toolchain_label = ctx.label,

src/main/starlark/builtins_bzl/common/cc/semantics.bzl

@@ -134,6 +134,20 @@ def _get_experimental_link_static_libraries_once(ctx):
 def _check_cc_shared_library_tags(ctx):
     pass
 
+def _cpp_modules_tools():
+    return {
+        "_aggregate_ddi": attr.label(
+            executable = True,
+            cfg = "exec",
+            default = "@" + _get_repo() + "//tools/cpp:aggregate-ddi",
+        ),
+        "_generate_modmap": attr.label(
+            executable = True,
+            cfg = "exec",
+            default = "@" + _get_repo() + "//tools/cpp:generate-modmap",
+        ),
+    }
+
 semantics = struct(
     toolchain = "@bazel_tools//tools/cpp:toolchain_type",
     ALLOWED_RULES_IN_DEPS = [
@@ -172,6 +186,7 @@ semantics = struct(
     get_proto_aspects = _get_proto_aspects,
     get_nocopts_attr = _get_nocopts_attr,
     get_experimental_link_static_libraries_once = _get_experimental_link_static_libraries_once,
+    cpp_modules_tools = _cpp_modules_tools,
     check_cc_shared_library_tags = _check_cc_shared_library_tags,
     BUILD_INFO_TRANLATOR_LABEL = "@bazel_tools//tools/build_defs/build_info:cc_build_info",
     CC_PROTO_TOOLCHAIN = "@rules_cc//cc/proto:toolchain_type",

src/test/java/com/google/devtools/build/lib/packages/util/Crosstool.java

@@ -582,7 +582,18 @@ public void write() throws IOException {
                 // We add an empty :malloc target in case we need it.
                 "cc_library(name = 'malloc')",
                 // Fake targets to get us through loading/analysis.
-                "exports_files(['grep-includes', 'link_dynamic_library'])");
+                "exports_files(['grep-includes', 'link_dynamic_library'])",
+                "",
+                "filegroup(",
+                "    name = 'aggregate-ddi',",
+                "    srcs = ['aggregate-ddi.sh'],",
+                ")",
+                "",
+                "filegroup(",
+                "    name = 'generate-modmap',",
+                "    srcs = ['generate-modmap.sh'],",
+                ")"
+            );
 
     config.create(crosstoolTop + "/mock_version/x86/bin/gcc");
     config.create(crosstoolTop + "/mock_version/x86/bin/ld");
@@ -598,6 +609,8 @@ public void write() throws IOException {
     config.create(crosstoolTop + "/grep-includes");
     config.create(crosstoolTop + "/build_interface_so");
     config.create(crosstoolTop + "/link_dynamic_library");
+    config.create(crosstoolTop + "/aggregate-ddi.sh");
+    config.create(crosstoolTop + "/generate-modmap.sh");
   }
 
   public void writeOSX() throws IOException {

src/test/shell/bazel/testdata/embedded_tools_srcs_deps

@@ -24,3 +24,8 @@
 //src/main/cpp/util:port
 //src/main/cpp/util:blaze_exit_code
 //src/main/cpp/util:logging
+//tools/cpp/modules_tools:aggregate-ddi
+//tools/cpp/modules_tools:aggregate-ddi-lib
+//tools/cpp/modules_tools:common
+//tools/cpp/modules_tools:generate-modmap
+//tools/cpp/modules_tools:generate-modmap-lib

tools/cpp/BUILD

@@ -21,13 +21,15 @@ exports_files(glob(["*.bzl"]))
 filegroup(
     name = "srcs",
     srcs = glob(["**"]) + [
+        "//tools/cpp/modules_tools:srcs",
         "//tools/cpp/runfiles:srcs",
     ],
 )
 
 filegroup(
     name = "embedded_tools",
     srcs = glob(["**"]) + [
+        "//tools/cpp/modules_tools:embedded_tools",
         "//tools/cpp/runfiles:embedded_tools",
     ],
 )

tools/cpp/BUILD.tools

@@ -96,6 +96,16 @@ filegroup(
     srcs = ["grep-includes.sh"],
 )
 
+filegroup(
+    name = "aggregate-ddi",
+    srcs = ["//tools/cpp/modules_tools:aggregate-ddi-bin"],
+)
+
+filegroup(
+    name = "generate-modmap",
+    srcs = ["//tools/cpp/modules_tools:generate-modmap-bin"],
+)
+
 filegroup(
     name = "empty",
     srcs = [],

tools/cpp/modules_tools/BUILD

@@ -0,0 +1,126 @@
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+filegroup(
+    name = "srcs",
+    srcs = glob(
+        ["**"],
+    ),
+    visibility = ["//tools/cpp:__pkg__"],
+)
+
+config_setting(
+    name = "windows",
+    constraint_values = ["@platforms//os:windows"],
+)
+
+COPTS = select({
+    ":windows": ["/std:c++17"],
+    "//conditions:default": ["-std=c++17"],
+})
+
+cc_library(
+    name = "common",
+    srcs = [
+        "common/common.cc",
+    ],
+    hdrs = [
+        "common/common.h",
+        "common/json.hpp",
+    ],
+    copts = COPTS,
+    includes = ["."],
+)
+
+cc_library(
+    name = "aggregate-ddi-lib",
+    srcs = ["aggregate-ddi/aggregate-ddi.cc"],
+    hdrs = ["aggregate-ddi/aggregate-ddi.h"],
+    copts = COPTS,
+    deps = [":common"],
+)
+
+cc_binary(
+    name = "aggregate-ddi",
+    srcs = ["aggregate-ddi/main.cc"],
+    copts = COPTS,
+    deps = [
+        ":aggregate-ddi-lib",
+    ],
+)
+
+cc_library(
+    name = "generate-modmap-lib",
+    srcs = ["generate-modmap/generate-modmap.cc"],
+    hdrs = ["generate-modmap/generate-modmap.h"],
+    copts = COPTS,
+    deps = [":common"],
+)
+
+cc_binary(
+    name = "generate-modmap",
+    srcs = ["generate-modmap/main.cc"],
+    copts = COPTS,
+    deps = [":generate-modmap-lib"],
+)
+
+filegroup(
+    name = "embedded_tools",
+    srcs = [
+        "BUILD.tools",
+        ":aggregate-ddi",
+        ":generate-modmap",
+    ],
+    visibility = ["//tools/cpp:__pkg__"],
+)
+
+cc_test(
+    name = "generate-modmap_test",
+    srcs = ["generate-modmap/generate-modmap_test.cc"],
+    copts = COPTS,
+    deps = [
+        ":generate-modmap-lib",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
+cc_test(
+    name = "aggregate-ddi_test",
+    srcs = ["aggregate-ddi/aggregate-ddi_test.cc"],
+    copts = COPTS,
+    deps = [
+        ":aggregate-ddi-lib",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
+cc_test(
+    name = "common_test",
+    srcs = ["common/common_test.cc"],
+    copts = COPTS,
+    deps = [
+        ":common",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
+cc_test(
+    name = "json_test",
+    srcs = ["common/json_test.cc"],
+    copts = COPTS,
+    deps = [
+        ":common",
+        "@com_google_googletest//:gtest_main",
+    ],
+)

tools/cpp/modules_tools/BUILD.tools

@@ -0,0 +1,22 @@
+package(default_visibility = ["//visibility:public"])
+
+config_setting(
+    name = "windows",
+    constraint_values = ["@platforms//os:windows"],
+)
+
+filegroup(
+    name = "aggregate-ddi-bin",
+    srcs = select({
+        ":windows": ["aggregate-ddi.exe"],
+        "//conditions:default": ["aggregate-ddi"],
+    }),
+)
+
+filegroup(
+    name = "generate-modmap-bin",
+    srcs = select({
+        ":windows": ["generate-modmap.exe"],
+        "//conditions:default": ["generate-modmap"],
+    }),
+)