Implement the cc_toolchain macro.

BEGIN_PUBLIC
Implement the cc_toolchain macro.

Things should be working at this point. This will be followed up with an example.
END_PUBLIC

PiperOrigin-RevId: 613436885
Change-Id: I1fc4a1e3a71c4f819998b69c73922821322d2991

3 files changed, 170 insertions, 0 deletions

diff --git a/cc/toolchains/actions/BUILD b/cc/toolchains/actions/BUILD
index 7546d67..13c14ee 100644
--- a/cc/toolchains/actions/BUILD
+++ b/cc/toolchains/actions/BUILD
@@ -139,6 +139,19 @@ cc_action_type(
 )
 
 cc_action_type_set(
+    name = "all_ar_actions",
+    actions = [":cpp_link_static_library"],
+)
+
+cc_action_type_set(
+    name = "all_assembly_actions",
+    actions = [
+        ":preprocess_assemble",
+        ":assemble",
+    ],
+)
+
+cc_action_type_set(
     name = "all_cpp_compile_actions",
     actions = [
         ":linkstamp_compile",
@@ -162,6 +175,14 @@ cc_action_type_set(
 )
 
 cc_action_type_set(
+    name = "all_compile_actions",
+    actions = [
+        ":all_cc_compile_actions",
+        ":all_cpp_compile_actions",
+    ],
+)
+
+cc_action_type_set(
     name = "all_cc_link_actions",
     actions = [
         ":cpp_link_executable",
diff --git a/cc/toolchains/impl/toolchain_config.bzl b/cc/toolchains/impl/toolchain_config.bzl
index 185f242..7a69dc0 100644
--- a/cc/toolchains/impl/toolchain_config.bzl
+++ b/cc/toolchains/impl/toolchain_config.bzl
@@ -80,6 +80,12 @@ def _cc_toolchain_config_impl(ctx):
             abi_libc_version = ctx.attr.abi_libc_version,
             builtin_sysroot = ctx.attr.sysroot or None,
         ),
+        # This allows us to support all_files.
+        # If all_files was simply an alias to
+        # ///cc/toolchains/actions:all_actions,
+        # then if a toolchain introduced a new type of action, it wouldn't get
+        # put in all_files.
+        DefaultInfo(files = depset(transitive = toolchain_config.files.values())),
     ]
 
 cc_toolchain_config = rule(
diff --git a/cc/toolchains/toolchain.bzl b/cc/toolchains/toolchain.bzl
new file mode 100644
index 0000000..0fbb45f
--- /dev/null
+++ b/cc/toolchains/toolchain.bzl
@@ -0,0 +1,143 @@
+# 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.
+"""Implementation of the cc_toolchain rule."""
+
+load("//cc:defs.bzl", "cc_toolchain")
+load(
+    "//cc/toolchains/impl:toolchain_config.bzl",
+    "cc_legacy_file_group",
+    "cc_toolchain_config",
+)
+
+visibility("public")
+
+# Taken from https://bazel.build/docs/cc-toolchain-config-reference#actions
+# TODO: This is best-effort. Update this with the correct file groups once we
+#  work out what actions correspond to what file groups.
+_LEGACY_FILE_GROUPS = {
+    "ar_files": [
+        "@rules_cc//cc/toolchains/actions:all_ar_actions",  # copybara-use-repo-external-label
+    ],
+    "as_files": [
+        "@rules_cc//cc/toolchains/actions:all_assembly_actions",  # copybara-use-repo-external-label
+    ],
+    "compiler_files": [
+        "@rules_cc//cc/toolchains/actions:cc_flags_make_variable",  # copybara-use-repo-external-label
+        "@rules_cc//cc/toolchains/actions:c_compile",  # copybara-use-repo-external-label
+        "@rules_cc//cc/toolchains/actions:cpp_compile",  # copybara-use-repo-external-label
+        "@rules_cc//cc/toolchains/actions:cpp_header_parsing",  # copybara-use-repo-external-label
+    ],
+    # There are no actions listed for coverage, dwp, and objcopy in action_names.bzl.
+    "coverage_files": [],
+    "dwp_files": [],
+    "linker_files": [
+        "@rules_cc//cc/toolchains/actions:cpp_link_dynamic_library",  # copybara-use-repo-external-label
+        "@rules_cc//cc/toolchains/actions:cpp_link_nodeps_dynamic_library",  # copybara-use-repo-external-label
+        "@rules_cc//cc/toolchains/actions:cpp_link_executable",  # copybara-use-repo-external-label
+    ],
+    "objcopy_files": [],
+    "strip_files": [
+        "@rules_cc//cc/toolchains/actions:strip",  # copybara-use-repo-external-label
+    ],
+}
+
+def cc_toolchain(
+        name,
+        dynamic_runtime_lib = None,
+        libc_top = None,
+        module_map = None,
+        output_licenses = [],
+        static_runtime_lib = None,
+        supports_header_parsing = False,
+        supports_param_files = True,
+        target_compatible_with = None,
+        exec_compatible_with = None,
+        compatible_with = None,
+        tags = [],
+        visibility = None,
+        **kwargs):
+    """A macro that invokes native.cc_toolchain under the hood.
+
+    Generated rules:
+        {name}: A `cc_toolchain` for this toolchain.
+        _{name}_config: A `cc_toolchain_config` for this toolchain.
+        _{name}_*_files: Generated rules that group together files for
+            "ar_files", "as_files", "compiler_files", "coverage_files",
+            "dwp_files", "linker_files", "objcopy_files", and "strip_files"
+            normally enumerated as part of the `cc_toolchain` rule.
+
+    Args:
+        name: str: The name of the label for the toolchain.
+        dynamic_runtime_lib: See cc_toolchain.dynamic_runtime_lib
+        libc_top: See cc_toolchain.libc_top
+        module_map: See cc_toolchain.module_map
+        output_licenses: See cc_toolchain.output_licenses
+        static_runtime_lib: See cc_toolchain.static_runtime_lib
+        supports_header_parsing: See cc_toolchain.supports_header_parsing
+        supports_param_files: See cc_toolchain.supports_param_files
+        target_compatible_with: target_compatible_with to apply to all generated
+          rules
+        exec_compatible_with: exec_compatible_with to apply to all generated
+          rules
+        compatible_with: compatible_with to apply to all generated rules
+        tags: Tags to apply to all generated rules
+        visibility: Visibility of toolchain rule
+        **kwargs: Args to be passed through to cc_toolchain_config.
+    """
+    all_kwargs = {
+        "compatible_with": compatible_with,
+        "exec_compatible_with": exec_compatible_with,
+        "tags": tags,
+        "target_compatible_with": target_compatible_with,
+    }
+    for group in _LEGACY_FILE_GROUPS:
+        if group in kwargs:
+            fail("Don't use legacy file groups such as %s. Instead, associate files with tools, actions, and args." % group)
+
+    config_name = "_{}_config".format(name)
+    cc_toolchain_config(
+        name = config_name,
+        visibility = ["//visibility:private"],
+        **(all_kwargs | kwargs)
+    )
+
+    # Provides ar_files, compiler_files, linker_files, ...
+    legacy_file_groups = {}
+    for group, actions in _LEGACY_FILE_GROUPS.items():
+        group_name = "_{}_{}".format(name, group)
+        cc_legacy_file_group(
+            name = group_name,
+            config = config_name,
+            actions = actions,
+            visibility = ["//visibility:private"],
+            **all_kwargs
+        )
+        legacy_file_groups[group] = group_name
+
+    if visibility != None:
+        all_kwargs["visibility"] = visibility
+
+    cc_toolchain(
+        name = name,
+        toolchain_config = config_name,
+        all_files = config_name,
+        dynamic_runtime_lib = dynamic_runtime_lib,
+        libc_top = libc_top,
+        module_map = module_map,
+        output_licenses = output_licenses,
+        static_runtime_lib = static_runtime_lib,
+        supports_header_parsing = supports_header_parsing,
+        supports_param_files = supports_param_files,
+        **(all_kwargs | legacy_file_groups)
+    )