# 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("@bazel_skylib//rules:copy_file.bzl", "copy_file")
load("@rules_cc//cc/toolchains:args.bzl", "cc_args")
load("@rules_cc//cc/toolchains:feature.bzl", "cc_feature")
load("@rules_cc//cc/toolchains:feature_constraint.bzl", "cc_feature_constraint")
load("@rules_cc//cc/toolchains:feature_set.bzl", "cc_feature_set")
load("@rules_cc//cc/toolchains:toolchain.bzl", "cc_toolchain")
load("//pw_toolchain/cc:builtin_module_map.bzl", "builtin_module_map")
load("//pw_toolchain/host_clang:paths.bzl", "LLVM_TOOLCHAIN")

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

licenses(["notice"])

filegroup(name = "empty")

cc_args(
    name = "link_with_lld",
    actions = ["@rules_cc//cc/toolchains/actions:link_actions"],
    args = ["-fuse-ld=lld"],
)

cc_args(
    name = "macos_link_libs",
    actions = ["@rules_cc//cc/toolchains/actions:link_actions"],
    args = [
        # Force dropping the system libc++.
        "-nostdlib++",
        # Use libc++ provided by the toolchain.
        LLVM_TOOLCHAIN + "/lib/libc++.a",
    ],
    target_compatible_with = ["@platforms//os:macos"],
)

cc_args(
    name = "linux_link_libs",
    actions = ["@rules_cc//cc/toolchains/actions:link_actions"],
    args = [
        "-pthread",
        "-stdlib=libc++",
        "--rtlib=compiler-rt",
        "--unwindlib=libunwind",
    ],
    target_compatible_with = ["@platforms//os:linux"],
)

cc_args(
    name = "libtool_darwin_flags",
    actions = ["@rules_cc//cc/toolchains/actions:cpp_link_static_library"],
    args = ["-no_warning_for_no_symbols"],
)

# Thread safety warnings are only supported by Clang.
cc_args(
    name = "thread_safety_warnings",
    actions = [
        "@rules_cc//cc/toolchains/actions:c_compile_actions",
        "@rules_cc//cc/toolchains/actions:cpp_compile_actions",
    ],
    args = [
        "-Wthread-safety",
        "-D_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1",
    ],
)

cc_args(
    name = "verbose_compiler_flags",
    actions = [
        "@rules_cc//cc/toolchains/actions:compile_actions",
        "@rules_cc//cc/toolchains/actions:link_actions",
    ],
    args = ["-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.
cc_feature(
    name = "verbose_compiler_output",
    args = [":verbose_compiler_flags"],
    feature_name = "verbose_compiler_output",
)

cc_args(
    name = "no_unknown_warning_option",
    actions = [
        "@rules_cc//cc/toolchains/actions:c_compile_actions",
        "@rules_cc//cc/toolchains/actions:cpp_compile_actions",
    ],
    args = [
        "-Wno-unknown-warning-option",
    ],
)

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

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

cc_feature(
    name = "asan_feature",
    args = ["//pw_toolchain/cc/args:asan"],
    feature_name = "asan",
    requires_any_of = [":asan_constraint"],
)

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"],
)

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

config_setting(
    name = "ubsan_enabled",
    flag_values = {
        ":ubsan": "true",
    },
)

cc_feature(
    name = "ubsan_feature",
    args = ["//pw_toolchain/cc/args:ubsan"],
    feature_name = "ubsan",
    requires_any_of = [":ubsan_constraint"],
)

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

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

config_setting(
    name = "tsan_enabled",
    flag_values = {
        ":tsan": "true",
    },
)

cc_feature(
    name = "tsan_feature",
    args = ["//pw_toolchain/cc/args:tsan"],
    feature_name = "tsan",
    requires_any_of = [":tsan_constraint"],
)

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

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

config_setting(
    name = "fuzztest_enabled",
    flag_values = {
        ":fuzztest": "true",
    },
)

cc_feature(
    name = "fuzztest_feature",
    args = ["//pw_toolchain/cc/args:fuzztest"],
    feature_name = "fuzztest",
)

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

# This is a sentinel feature defined by rules_go. It is by definition
# unsupported: rules_go will disable this feature when linking Go code.
cc_feature(
    name = "rules_go_unsupported_feature",
    feature_name = "rules_go_unsupported_feature",
)

cc_feature_constraint(
    name = "rules_go_constraint",

    # This constraint is saying "not not Golang" (yes Golang / only Golang).
    none_of = [":rules_go_unsupported_feature"],
)

# Golang doesn't link with PIE enabled. See pwbug.dev/347708308.
#
# We want to disable PIE only when we're *not* compiling Golang code.
cc_args(
    name = "no_pie_for_go_flags",
    actions = ["@rules_cc//cc/toolchains/actions:link_actions"],
    args = [
        "-no-pie",
    ],
    requires_any_of = [":rules_go_constraint"],
    target_compatible_with = ["@platforms//os:linux"],
)

cc_args(
    name = "silence_cgo_warnings",
    actions = [
        "@rules_cc//cc/toolchains/actions:compile_actions",
        "@rules_cc//cc/toolchains/actions:link_actions",
    ],
    args = ["-Wno-unused-parameter"],
    requires_any_of = [":rules_go_constraint"],
)

cc_feature(
    name = "supports_pic",
    feature_name = "supports_pic",
)

# Symlink to clangd, for user convenience.
copy_file(
    name = "copy_clangd",
    src = select({
        "@platforms//os:macos": "@llvm_toolchain_macos//:bin/clangd",
        "//conditions:default": "@llvm_toolchain//:bin/clangd",
    }),
    out = "clangd",
    allow_symlink = True,
)

# Symlink to clang-tidy, for user convenience.
copy_file(
    name = "copy_clang_tidy",
    src = select({
        "@platforms//os:macos": "@llvm_toolchain_macos//:clang-tidy",
        "//conditions:default": "@llvm_toolchain//:clang-tidy",
    }),
    out = "clang-tidy",
    allow_symlink = True,
    is_executable = True,
)

cc_feature(
    name = "use_module_maps",
    args = ["//pw_toolchain/cc/args:dependent_module_map_files"],
    feature_name = "use_module_maps",
    requires_any_of = [":module_maps"],
)

cc_feature(
    name = "module_maps",
    feature_name = "module_maps",
)

cc_feature(
    name = "layering_check_feature",
    args = [
        "//pw_toolchain/cc/args:layering_check",
        "//pw_toolchain/cc/args:module_name",
        "//pw_toolchain/cc/args:module_map_file",
    ],
    feature_name = "layering_check",
    implies = [":use_module_maps"],
)

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

config_setting(
    name = "layering_check_enabled",
    flag_values = {":layering_check": "True"},
)

builtin_module_map(
    name = "builtin_module_map",
    include_directories = select({
        "@platforms//os:linux": [
            "@llvm_toolchain//:include-x86_64-unknown-linux-gnu-c++-v1",
            "@llvm_toolchain//:include-c++-v1",
            "@llvm_toolchain//:lib-clang-include",
            "@linux_sysroot//:usr-include-x86_64-linux-gnu",
            "@linux_sysroot//:usr-include-arm-linux-gnueabihf",
            "@linux_sysroot//:usr-include",
        ],
        "@platforms//os:macos": [
            "@llvm_toolchain_macos//:include-x86_64-unknown-linux-gnu-c++-v1",
            "@llvm_toolchain_macos//:include-c++-v1",
            "@llvm_toolchain_macos//:lib-clang-include",
            "@macos_sysroot//:usr-include",
            "@macos_sysroot//:CoreFoundation.framework-Headers",
            "@macos_sysroot//:IOKit.framework-Headers",
            "@macos_sysroot//:Security.framework-Headers",
        ],
        "//conditions:default": [],
    }),
)

alias(
    name = "sysroot_root",
    actual = select({
        "@platforms//os:linux": "@linux_sysroot//:sysroot",
        "@platforms//os:macos": "@macos_sysroot//:sysroot",
        "//conditions:default": "//pw_build:empty_cc_library",
    }),
)

cc_toolchain(
    name = "host_toolchain",
    args = select({
        "@platforms//os:linux": [
            ":linux_link_libs",
            ":no_pie_for_go_flags",
            "@linux_sysroot//:sysroot",
        ],
        "@platforms//os:macos": [
            ":macos_link_libs",
            ":libtool_darwin_flags",
            "@macos_sysroot//:sysroot",
        ],
        "//conditions:default": [],
    }) + [
        ":thread_safety_warnings",
        ":link_with_lld",
        "//pw_toolchain/cc/args:debugging",
        "//pw_toolchain/cc/args:reduced_size",
        "//pw_toolchain/cc/args:no_canonical_prefixes",
        "//pw_toolchain/cc/args:no_rtti",
        "//pw_toolchain/cc/args:wno_register",
        "//pw_toolchain/cc/args:wnon_virtual_dtor",
        "//pw_toolchain/cc/args:common_warnings",
        "//pw_toolchain/cc/args:color_diagnostics",
        # Must go after the general warnings that are enabled.
        ":silence_cgo_warnings",
    ] + select({
        "//pw_build:kythe": [":no_unknown_warning_option"],
        "//conditions:default": [],
    }),
    enabled_features = [
        "@rules_cc//cc/toolchains/args:experimental_replace_legacy_action_config_features",
        ":supports_pic",
        ":module_maps",
        ":rules_go_unsupported_feature",
        ":rules_rust_unsupported_feature",
        "//pw_toolchain/cc/capability:compiler_is_clang",
        "//pw_toolchain/cc/capability:linker_is_clang",
    ] + select({
        ":asan_enabled": [":asan_feature"],
        "//conditions:default": [],
    }) + select({
        ":ubsan_enabled": [":ubsan_feature"],
        "//conditions:default": [],
    }) + select({
        ":tsan_enabled": [":tsan_feature"],
        "//conditions:default": [],
    }) + select({
        "//pw_toolchain/cc:c++17_enabled": ["//pw_toolchain/cc/args:c++17_feature"],
        "//conditions:default": [],
    }) + select({
        "//pw_toolchain/cc:c++20_enabled": ["//pw_toolchain/cc/args:c++20_feature"],
        "//conditions:default": [],
    }) + select({
        ":fuzztest_enabled": [":fuzztest_feature"],
        "//conditions:default": [],
    }),
    known_features = [
        "@rules_cc//cc/toolchains/args:experimental_replace_legacy_action_config_features",
        ":layering_check_feature",
        ":module_maps",
        ":use_module_maps",
        ":asan_feature",
        ":ubsan_feature",
        ":tsan_feature",
        ":verbose_compiler_output",
        ":rules_rust_unsupported_feature",
        ":supports_pic",
        "//pw_toolchain/cc/args:c++17_feature",
        "//pw_toolchain/cc/args:c++20_feature",
        "//pw_toolchain/cc/capability:compiler_is_clang",
        "//pw_toolchain/cc/capability:linker_is_clang",
    ],
    # TODO: https://pwbug.dev/219091175 - Remove this select (always set this to
    # builtin_module_map) once all Pigweed downstream projects are on Bazel 8.
    module_map = select({
        ":layering_check_enabled": ":builtin_module_map",
        "//conditions:default": None,
    }),
    tool_map = select({
        "@platforms//os:macos": "@llvm_toolchain_macos//:all_tools",
        "//conditions:default": "@llvm_toolchain//:all_tools",
    }),
)

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",
)