# Copyright 2023 The Pigweed Authors
#
# 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
#
#     https://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.

load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
load(
    "@pw_toolchain//cc_toolchain:defs.bzl",
    "pw_cc_action_files",
    "pw_cc_feature",
    "pw_cc_feature_set",
    "pw_cc_flag_set",
    "pw_cc_toolchain",
)
load("@pw_xcode_command_line_tools//:defs.bzl", "XCODE_SDK_PATH")

package(default_visibility = ["//visibility:public"])

licenses(["notice"])

filegroup(name = "empty")

pw_cc_flag_set(
    name = "macos_link_libs",
    actions = ["@pw_toolchain//actions:all_link_actions"],
    flags = [
        # Force dropping the system libc++.
        "-nostdlib++",
        # Use libc++ provided by the toolchain.
        "external/llvm_toolchain/lib/libc++.a",
    ],
    target_compatible_with = ["@platforms//os:macos"],
)

pw_cc_flag_set(
    name = "linux_link_libs",
    actions = ["@pw_toolchain//actions:all_link_actions"],
    flags = [
        "-pthread",
        "-stdlib=libc++",
        "--rtlib=compiler-rt",
        "--unwindlib=libunwind",
    ],
    target_compatible_with = ["@platforms//os:linux"],
)

pw_cc_flag_set(
    name = "libtool_darwin_flags",
    actions = ["@pw_toolchain//actions:cpp_link_static_library"],
    flags = ["-no_warning_for_no_symbols"],
)

# Although we use similar warnings for clang and arm_gcc, we don't have one
# centralized list, since we might want to use different warnings based on the
# compiler in the future.
pw_cc_flag_set(
    name = "warnings",
    actions = [
        "@pw_toolchain//actions:all_c_compiler_actions",
        "@pw_toolchain//actions:all_cpp_compiler_actions",
    ],
    flags = [
        "-Wall",
        "-Wextra",
        # Make all warnings errors, except for the exemptions below.
        "-Werror",
        "-Wno-error=cpp",  # preprocessor #warning statement
        "-Wno-error=deprecated-declarations",  # [[deprecated]] attribute
    ],
)

# Thread safety warnings are only supported by Clang.
pw_cc_flag_set(
    name = "thread_safety_warnings",
    actions = [
        "@pw_toolchain//actions:all_c_compiler_actions",
        "@pw_toolchain//actions:all_cpp_compiler_actions",
    ],
    flags = [
        "-Wthread-safety",
        "-D_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1",
    ],
)

pw_cc_flag_set(
    name = "verbose_compiler_flags",
    actions = [
        "@pw_toolchain//actions:all_asm_actions",
        "@pw_toolchain//actions:all_c_compiler_actions",
        "@pw_toolchain//actions:all_cpp_compiler_actions",
        "@pw_toolchain//actions:all_link_actions",
    ],
    flags = ["-v"],
)

# A feature that can be easily toggled to include extra compiler output to help
# debug things like include search path ordering and showing all the flags
# passed to the compiler.
#
# Add `--features=verbose_compiler_output` to your Bazel invocation to enable.
pw_cc_feature(
    name = "verbose_compiler_output",
    enabled = False,
    feature_name = "verbose_compiler_output",
    flag_sets = [":verbose_compiler_flags"],
)

pw_cc_flag_set(
    name = "no_unknown_warning_option",
    actions = [
        "@pw_toolchain//actions:all_c_compiler_actions",
        "@pw_toolchain//actions:all_cpp_compiler_actions",
    ],
    flags = [
        "-Wno-unknown-warning-option",
    ],
)

pw_cc_action_files(
    name = "sysroot_files",
    srcs = select({
        "@platforms//os:linux": [
            "@linux_sysroot//:all",
        ],
        "//conditions:default": [],
    }),
    actions = [
        "@pw_toolchain//actions:all_compiler_actions",
        "@pw_toolchain//actions:all_link_actions",
    ],
)

bool_flag(
    name = "asan",
    build_setting_default = False,
)

config_setting(
    name = "asan_enabled",
    flag_values = {
        ":asan": "true",
    },
)

pw_cc_feature(
    name = "asan_feature",
    enabled = select({
        ":asan_enabled": True,
        "//conditions:default": False,
    }),
    feature_name = "asan",
    flag_sets = ["@pw_toolchain//flag_sets:asan"],
    requires_any_of = [":asan_constraint"],
)

pw_cc_feature_set(
    name = "asan_constraint",
    # Rust uses the C++ linker, but not the C++ compiler, so we need to ensure
    # -fsanitize=address is not be specified during Rust linking.
    all_of = [":rules_rust_unsupported_feature"],
)

# This is a sentinel feature defined by rules_rust. It is by definition
# unsupported: rules_rust will disable this feature when linking Rust code.
pw_cc_feature(
    name = "rules_rust_unsupported_feature",
    enabled = True,
    feature_name = "rules_rust_unsupported_feature",
)

pw_cc_feature(
    name = "supports_pic",
    enabled = True,
    feature_name = "supports_pic",
    overrides = "@pw_toolchain//features/well_known:supports_pic",
)

pw_cc_toolchain(
    name = "host_toolchain",
    action_configs = [
        "@llvm_toolchain//:ar",
        "@llvm_toolchain//:clang",
        "@llvm_toolchain//:clang++",
        "@llvm_toolchain//:lld",
        "@llvm_toolchain//:llvm-cov",
        "@llvm_toolchain//:llvm-objcopy",
        "@llvm_toolchain//:llvm-objdump",
        "@llvm_toolchain//:llvm-strip",
    ],
    builtin_sysroot = select({
        "@platforms//os:linux": "external/linux_sysroot",
        "@platforms//os:macos": XCODE_SDK_PATH,
        "//conditions:default": "",
    }),
    compiler = "clang",
    cxx_builtin_include_directories = select({
        "@platforms//os:linux": [
            "%package(@llvm_toolchain//)%/include/x86_64-unknown-linux-gnu/c++/v1",
            "%package(@llvm_toolchain//)%/include/c++/v1",
            "%package(@llvm_toolchain//)%/lib/clang/18/include",
            "%sysroot%/usr/local/include",
            "%sysroot%/usr/include/x86_64-linux-gnu",
            "%sysroot%/usr/include",
        ],
        "@platforms//os:macos": [
            "%sysroot%/usr/include",
            "%sysroot%/System/Library/Frameworks/CoreFoundation.framework/Headers",
            "%sysroot%/System/Library/Frameworks/IOKit.framework/Headers",
            "%sysroot%/System/Library/Frameworks/Security.framework/Headers",
            "%package(@llvm_toolchain//)%/include/c++/v1",
            "%package(@llvm_toolchain//)%/lib/clang/18/include",
        ],
        "//conditions:default": [],
    }),
    extra_action_files = [":sysroot_files"],
    flag_sets = select({
        "@platforms//os:linux": [
            ":linux_link_libs",
        ],
        "@platforms//os:macos": [
            ":macos_link_libs",
            ":libtool_darwin_flags",
        ],
        "//conditions:default": [],
    }) + [
        ":warnings",
        ":thread_safety_warnings",
        "@pw_toolchain//flag_sets:c++17",
        "@pw_toolchain//flag_sets:debugging",
        "@pw_toolchain//flag_sets:reduced_size",
        "@pw_toolchain//flag_sets:no_canonical_prefixes",
        "@pw_toolchain//flag_sets:no_rtti",
        "@pw_toolchain//flag_sets:wno_register",
        "@pw_toolchain//flag_sets:wnon_virtual_dtor",
    ] + select({
        "//pw_build:kythe": [":no_unknown_warning_option"],
        "//conditions:default": [],
    }),
    # The implementations of some "legacy features" built into Bazel use
    # `target_libc` to determine if a toolchain targets MacOS,
    # https://github.com/bazelbuild/bazel/blob/release-7.0.0-pre.20230816.3rc1/src/main/java/com/google/devtools/build/lib/rules/cpp/CcModule.java#L1301-L1304
    #
    # `target_cpu` appears to only potentially do magic things for the Android
    # NDK, so it's omitted here.
    target_libc = select({
        "@platforms//os:macos": "macosx",
        "//conditions:default": None,
    }),
    toolchain_features = [
        ":asan_feature",
        ":verbose_compiler_output",
        ":rules_rust_unsupported_feature",
        ":supports_pic",
    ],
    toolchain_identifier = "host-toolchain",
)

toolchain(
    name = "host_cc_toolchain_linux",
    exec_compatible_with = [
        "@platforms//os:linux",
    ],
    target_compatible_with = [
        "@platforms//os:linux",
    ],
    toolchain = ":host_toolchain",
    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
)

toolchain(
    name = "host_cc_toolchain_macos",
    exec_compatible_with = [
        "@platforms//os:macos",
    ],
    target_compatible_with = [
        "@platforms//os:macos",
    ],
    toolchain = ":host_toolchain",
    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
)