bazel/toolchain/BUILD.bazel

load("@rules_cc//cc/toolchains:args.bzl", "cc_args")
load("@rules_cc//cc/toolchains:args_list.bzl", "cc_args_list")
load("@rules_cc//cc/toolchains:feature.bzl", "cc_feature")
load("@rules_cc//cc/toolchains:toolchain.bzl", "cc_toolchain")
load("configurable_feature.bzl", "configurable_toolchain_feature")

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

cc_args(
    name = "armv6m-none-eabi",
    actions = [
        "@rules_cc//cc/toolchains/actions:compile_actions",
        "@rules_cc//cc/toolchains/actions:link_actions",
    ],
    args = ["--target=armv6m-none-eabi"],
)

cc_args(
    name = "armv8m.main-none-eabi",
    actions = [
        "@rules_cc//cc/toolchains/actions:compile_actions",
        "@rules_cc//cc/toolchains/actions:link_actions",
    ],
    args = ["--target=armv8m.main-none-eabi"],
)

cc_args(
    name = "cortex-m0",
    actions = [
        "@rules_cc//cc/toolchains/actions:compile_actions",
        "@rules_cc//cc/toolchains/actions:link_actions",
    ],
    args = [
        "-mcpu=cortex-m0plus",
        "-mthumb",
    ],
)

cc_args(
    name = "cortex-m33",
    actions = [
        "@rules_cc//cc/toolchains/actions:compile_actions",
        "@rules_cc//cc/toolchains/actions:link_actions",
    ],
    args = [
        "-mcpu=cortex-m33",
        "-march=armv8-m.main+fp+dsp",
        "-mfloat-abi=softfp",
        "-mthumb",
        "-mcmse",
    ],
)

# :no_canonical_system_headers and :no_canonical_prefixes both prevent built-in
# compiler include directories from resolving to absolute paths. Prefer to use
# :bazel_no_absolute_paths, since it correctly guides based on the current
# compiler type.
cc_args(
    name = "no_canonical_system_headers",
    actions = ["@rules_cc//cc/toolchains/actions:compile_actions"],
    args = ["-fno-canonical-system-headers"],
)

cc_args(
    name = "no_canonical_prefixes",
    actions = ["@rules_cc//cc/toolchains/actions:compile_actions"],
    args = ["-no-canonical-prefixes"],
)

cc_args_list(
    name = "bazel_no_absolute_paths",
    args = select({
        "//bazel/constraint:pico_toolchain_clang_enabled": [],
        "//conditions:default": [":no_canonical_system_headers"],
    }) + [":no_canonical_prefixes"],
)

cc_args(
    name = "llvm-libc_args",
    actions = ["@rules_cc//cc/toolchains/actions:link_actions"],
    args = [
        "-nostdlib++",
        "-nostartfiles",
        "-Wl,-lc++",
    ],
    visibility = ["//visibility:private"],
)

cc_args(
    name = "opt_debug_args",
    actions = [
        "@rules_cc//cc/toolchains/actions:compile_actions",
        "@rules_cc//cc/toolchains/actions:link_actions",
    ],
    args = [
        "-Og",  # TODO: Make this configurable.
        "-g3",
    ],
)

configurable_toolchain_feature(
    name = "gc_sections",
    copts = [
        "-ffunction-sections",
        "-fdata-sections",
    ],
    linkopts = ["-Wl,--gc-sections"],
)

configurable_toolchain_feature(
    name = "cxx_no_exceptions",
    cxxopts = [
        "-fno-exceptions",
        "-fno-unwind-tables",
    ],
)

configurable_toolchain_feature(
    name = "cxx_no_rtti",
    cxxopts = ["-fno-rtti"],
)

configurable_toolchain_feature(
    name = "cxx_no_cxa_atexit",
    cxxopts = ["-fno-use-cxa-atexit"],
)

configurable_toolchain_feature(
    name = "override_max_page_size",
    linkopts = ["-Wl,-z,max-page-size=4096"],
)

# TODO: Make this shim unnecessary.
cc_args_list(
    name = "all_opt_debug_args",
    args = [":opt_debug_args"],
)

cc_feature(
    name = "override_debug",
    args = [":all_opt_debug_args"],
    overrides = "@rules_cc//cc/toolchains/features:dbg",
)

HOSTS = (
    ("linux", "x86_64"),
    ("linux", "aarch64"),
    ("win", "x86_64"),
    ("mac", "x86_64"),
    ("mac", "aarch64"),
)

_HOST_OS_CONSTRAINTS = {
    "linux": "@platforms//os:linux",
    "win": "@platforms//os:windows",
    "mac": "@platforms//os:macos",
}

_HOST_CPU_CONSTRAINTS = {
    "x86_64": "@platforms//cpu:x86_64",
    "aarch64": "@platforms//cpu:aarch64",
}

[cc_toolchain(
    name = "arm_gcc_{}-{}_toolchain_cortex-m".format(host_os, host_cpu),
    tool_map = "@arm_gcc_{}-{}//:all_tools".format(host_os, host_cpu),
    args = select({
        "//bazel/constraint:rp2040": [":cortex-m0"],
        "//bazel/constraint:rp2350": [":cortex-m33"],
        "//conditions:default": [],
    }) + [
        ":bazel_no_absolute_paths",
    ],
    exec_compatible_with = [
        _HOST_CPU_CONSTRAINTS[host_cpu],
        _HOST_OS_CONSTRAINTS[host_os],
    ],
    tags = ["manual"],  # Don't try to build this in wildcard builds.
    known_features = [
        "@rules_cc//cc/toolchains/args:experimental_replace_legacy_action_config_features",
        "@pico-sdk//bazel/toolchain:override_debug",
        "@pico-sdk//bazel/toolchain:gc_sections",
        "@pico-sdk//bazel/toolchain:cxx_no_exceptions",
        "@pico-sdk//bazel/toolchain:cxx_no_rtti",
        "@pico-sdk//bazel/toolchain:cxx_no_cxa_atexit",
        "@pico-sdk//bazel/toolchain:override_max_page_size",
    ],
    enabled_features = [
        "@rules_cc//cc/toolchains/args:experimental_replace_legacy_action_config_features",
        "@pico-sdk//bazel/toolchain:override_debug",
    ] + select({
        "//bazel/constraint:pico_no_gc_sections_enabled": [],
        "//conditions:default": [":gc_sections"],
    }) + select({
        "//bazel/constraint:pico_cxx_enable_exceptions_enabled": [],
        "//conditions:default": [":cxx_no_exceptions"],
    }) + select({
        "//bazel/constraint:pico_cxx_enable_rtti_enabled": [],
        "//conditions:default": [":cxx_no_rtti"],
    }) + select({
        "//bazel/constraint:pico_cxx_enable_cxa_atexit_enabled": [],
        "//conditions:default": [":cxx_no_cxa_atexit"],
    }) + select({
        "//bazel/constraint:pico_use_default_max_page_size_enabled": [],
        "//conditions:default": [":override_max_page_size"],
    }),
) for host_os, host_cpu in HOSTS]

[cc_toolchain(
    name = "clang_{}-{}_toolchain_cortex-m".format(host_os, host_cpu),
    tool_map = "@clang_{}-{}//:all_tools".format(host_os, host_cpu),
    args = select({
        "//bazel/constraint:rp2040": [
            ":armv6m-none-eabi",
            ":cortex-m0",
        ],
        "//bazel/constraint:rp2350": [
            ":armv8m.main-none-eabi",
            ":cortex-m33",
        ],
        "//conditions:default": [],
    }) + [
        ":bazel_no_absolute_paths",
        ":llvm-libc_args",
    ],
    exec_compatible_with = [
        _HOST_CPU_CONSTRAINTS[host_cpu],
        _HOST_OS_CONSTRAINTS[host_os],
    ],
    tags = ["manual"],  # Don't try to build this in wildcard builds.
    known_features = [
        "@rules_cc//cc/toolchains/args:experimental_replace_legacy_action_config_features",
        "@pico-sdk//bazel/toolchain:override_debug",
        "@pico-sdk//bazel/toolchain:gc_sections",
        "@pico-sdk//bazel/toolchain:cxx_no_exceptions",
        "@pico-sdk//bazel/toolchain:cxx_no_rtti",
        "@pico-sdk//bazel/toolchain:cxx_no_cxa_atexit",
        "@pico-sdk//bazel/toolchain:override_max_page_size",
    ],
    enabled_features = [
        "@rules_cc//cc/toolchains/args:experimental_replace_legacy_action_config_features",
        "@pico-sdk//bazel/toolchain:override_debug",
    ] + select({
        "//bazel/constraint:pico_no_gc_sections_enabled": [],
        "//conditions:default": [":gc_sections"],
    }) + select({
        "//bazel/constraint:pico_cxx_enable_exceptions_enabled": [],
        "//conditions:default": [":cxx_no_exceptions"],
    }) + select({
        "//bazel/constraint:pico_cxx_enable_rtti_enabled": [],
        "//conditions:default": [":cxx_no_rtti"],
    }) + select({
        "//bazel/constraint:pico_cxx_enable_cxa_atexit_enabled": [],
        "//conditions:default": [":cxx_no_cxa_atexit"],
    }) + select({
        "//bazel/constraint:pico_use_default_max_page_size_enabled": [],
        "//conditions:default": [":override_max_page_size"],
    }),
) for host_os, host_cpu in HOSTS]

[toolchain(
    name = "{}-{}-rp2040".format(host_os, host_cpu),
    exec_compatible_with = [
        _HOST_CPU_CONSTRAINTS[host_cpu],
        _HOST_OS_CONSTRAINTS[host_os],
    ],
    target_compatible_with = [
        "@pico-sdk//bazel/constraint:rp2040",
    ],
    toolchain = select({
        "//bazel/constraint:pico_toolchain_clang_enabled": "clang_{}-{}_toolchain_cortex-m".format(host_os, host_cpu),
        "//conditions:default": ":arm_gcc_{}-{}_toolchain_cortex-m".format(host_os, host_cpu),
    }),
    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
) for host_os, host_cpu in HOSTS]

[toolchain(
    name = "{}-{}-rp2350".format(host_os, host_cpu),
    exec_compatible_with = [
        _HOST_CPU_CONSTRAINTS[host_cpu],
        _HOST_OS_CONSTRAINTS[host_os],
    ],
    target_compatible_with = [
        "@pico-sdk//bazel/constraint:rp2350",
    ],
    toolchain = select({
        "//bazel/constraint:pico_toolchain_clang_enabled": "clang_{}-{}_toolchain_cortex-m".format(host_os, host_cpu),
        "//conditions:default": ":arm_gcc_{}-{}_toolchain_cortex-m".format(host_os, host_cpu),
    }),
    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
) for host_os, host_cpu in HOSTS]