# Copyright (C) 2021 The Android Open Source Project
#
# 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.

load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
load(":cc_constants.bzl", "constants")
load(
    ":cc_library_common.bzl",
    "get_includes_paths",
    "is_external_directory",
    "parse_sdk_version",
    "system_dynamic_deps_defaults",
)
load(":composed_transitions.bzl", "drop_sanitizer_transition")
load(":stl.bzl", "stl_info_from_attr")

# "cc_object" module copts, taken from build/soong/cc/object.go
_CC_OBJECT_COPTS = ["-fno-addrsig"]

# partialLd module link opts, taken from build/soong/cc/builder.go
# https://cs.android.com/android/platform/superproject/+/master:build/soong/cc/builder.go;l=87;drc=f2be52c4dcc2e3d743318e106633e61de0ad2afd
_CC_OBJECT_LINKOPTS = [
    "-fuse-ld=lld",
    "-nostdlib",
    "-no-pie",
    "-Wl,-r",
]

CcObjectInfo = provider(fields = [
    # The merged compilation outputs for this cc_object and its transitive
    # dependencies.
    "objects",
])

def split_srcs_hdrs(files):
    headers = []
    non_headers_as = []
    non_headers_c = []
    for f in files:
        if f.extension in constants.hdr_exts:
            headers.append(f)
        elif f.extension in constants.as_src_exts:
            non_headers_as.append(f)
        else:
            non_headers_c.append(f)
    return non_headers_c, non_headers_as, headers

def _objcopy_noaddrsig(ctx, noaddrsig_output, linking_output, cc_toolchain):
    output_file = ctx.actions.declare_file(noaddrsig_output)

    feature_configuration = cc_common.configure_features(
        ctx = ctx,
        cc_toolchain = cc_toolchain,
        requested_features = ctx.features,
        unsupported_features = ctx.disabled_features,
    )

    objcopy_path = cc_common.get_tool_for_action(
        feature_configuration = feature_configuration,
        action_name = "objcopy",
    )
    command_line = cc_common.get_memory_inefficient_command_line(
        feature_configuration = feature_configuration,
        action_name = "objcopy",
        variables = cc_common.empty_variables(),
    )

    args = ctx.actions.args()
    args.add_all(command_line)
    args.add("--remove-section=.llvm_addrsig")
    args.add(linking_output.executable)
    args.add(output_file)

    ctx.actions.run(
        executable = objcopy_path,
        arguments = [args],
        inputs = depset(
            direct = [linking_output.executable],
            transitive = [
                cc_toolchain.all_files,
            ],
        ),
        outputs = [output_file],
        mnemonic = "CppObjcopyNoAddrsig",
    )

    return output_file

def _cc_object_impl(ctx):
    cc_toolchain = ctx.toolchains["//prebuilts/clang/host/linux-x86:nocrt_toolchain"].cc

    extra_features = []

    extra_disabled_features = [
        "disable_pack_relocations",
        "dynamic_executable",
        "dynamic_linker",
        "linker_flags",
        "no_undefined_symbols",
        "pack_dynamic_relocations",
        "strip_debug_symbols",
        # TODO(cparsons): Look into disabling this feature for nocrt toolchain?
        "use_libcrt",
    ]
    if is_external_directory(ctx.label.package):
        extra_disabled_features.append("non_external_compiler_flags")
        extra_features.append("external_compiler_flags")
    else:
        extra_features.append("non_external_compiler_flags")
        extra_disabled_features.append("external_compiler_flags")

    apex_min_sdk_version = ctx.attr._apex_min_sdk_version[BuildSettingInfo].value
    if ctx.attr.crt and apex_min_sdk_version:
        extra_disabled_features.append("sdk_version_default")
        extra_features += parse_sdk_version(apex_min_sdk_version)
    elif ctx.attr.min_sdk_version:
        extra_disabled_features.append("sdk_version_default")
        extra_features += parse_sdk_version(ctx.attr.min_sdk_version)

    # Disable coverage for cc object because we link cc objects below and
    # clang will link extra lib behind the scene to support profiling if coverage
    # is enabled, so the symbols of the extra lib will be loaded into the generated
    # object file. When later we link a shared library that depends on more than
    # one such cc objects it will fail due to the duplicated symbols problem.
    extra_disabled_features.append("coverage")

    feature_configuration = cc_common.configure_features(
        ctx = ctx,
        cc_toolchain = cc_toolchain,
        requested_features = ctx.features + extra_features,
        unsupported_features = ctx.disabled_features + extra_disabled_features,
    )

    compilation_contexts = []
    deps_objects = []
    for obj in ctx.attr.objs:
        compilation_contexts.append(obj[CcInfo].compilation_context)
        deps_objects.append(obj[CcObjectInfo].objects)
    for includes_dep in ctx.attr.includes_deps:
        compilation_contexts.append(includes_dep[CcInfo].compilation_context)

    product_variables = ctx.attr._android_product_variables[platform_common.TemplateVariableInfo]
    asflags = [ctx.expand_make_variables("asflags", flag, product_variables.variables) for flag in ctx.attr.asflags]

    srcs_c, srcs_as, private_hdrs = split_srcs_hdrs(ctx.files.srcs + ctx.files.srcs_as)

    (compilation_context, compilation_outputs_c) = cc_common.compile(
        name = ctx.label.name,
        actions = ctx.actions,
        feature_configuration = feature_configuration,
        cc_toolchain = cc_toolchain,
        srcs = srcs_c,
        includes = get_includes_paths(ctx, ctx.attr.local_includes) + get_includes_paths(ctx, ctx.attr.absolute_includes, package_relative = False),
        public_hdrs = ctx.files.hdrs,
        private_hdrs = private_hdrs,
        user_compile_flags = ctx.attr.copts,
        compilation_contexts = compilation_contexts,
    )

    (compilation_context, compilation_outputs_as) = cc_common.compile(
        name = ctx.label.name,
        actions = ctx.actions,
        feature_configuration = feature_configuration,
        cc_toolchain = cc_toolchain,
        srcs = srcs_as,
        includes = get_includes_paths(ctx, ctx.attr.local_includes) + get_includes_paths(ctx, ctx.attr.absolute_includes, package_relative = False),
        public_hdrs = ctx.files.hdrs,
        private_hdrs = private_hdrs,
        user_compile_flags = ctx.attr.copts + asflags,
        compilation_contexts = compilation_contexts,
    )

    # do not propagate includes
    compilation_context = cc_common.create_compilation_context(
        headers = compilation_context.headers,
        defines = compilation_context.defines,
        local_defines = compilation_context.local_defines,
    )

    objects_to_link = cc_common.merge_compilation_outputs(compilation_outputs = deps_objects + [compilation_outputs_c, compilation_outputs_as])

    user_link_flags = [] + ctx.attr.linkopts
    user_link_flags.extend(_CC_OBJECT_LINKOPTS)
    additional_inputs = []

    if ctx.attr.linker_script != None:
        linker_script = ctx.files.linker_script[0]
        user_link_flags.append("-Wl,-T," + linker_script.path)
        additional_inputs.append(linker_script)

    # partially link if there are multiple object files
    if len(objects_to_link.objects) + len(objects_to_link.pic_objects) > 1:
        linking_output = cc_common.link(
            name = ctx.label.name + ".addrsig.o",
            actions = ctx.actions,
            feature_configuration = feature_configuration,
            cc_toolchain = cc_toolchain,
            user_link_flags = user_link_flags,
            compilation_outputs = objects_to_link,
            additional_inputs = additional_inputs,
        )

        noaddrsig_output = _objcopy_noaddrsig(ctx, ctx.label.name + ".o", linking_output, cc_toolchain)

        files = depset([noaddrsig_output])
    else:
        files = depset(objects_to_link.objects + objects_to_link.pic_objects)

    return [
        DefaultInfo(files = files),
        CcInfo(compilation_context = compilation_context),
        CcObjectInfo(objects = objects_to_link),
    ]

_cc_object = rule(
    implementation = _cc_object_impl,
    cfg = drop_sanitizer_transition,
    attrs = {
        "srcs": attr.label_list(allow_files = constants.all_dot_exts),
        "srcs_as": attr.label_list(allow_files = constants.all_dot_exts),
        "hdrs": attr.label_list(allow_files = constants.hdr_dot_exts),
        "absolute_includes": attr.string_list(),
        "local_includes": attr.string_list(),
        "copts": attr.string_list(),
        "asflags": attr.string_list(),
        "linkopts": attr.string_list(),
        "objs": attr.label_list(
            providers = [CcInfo, CcObjectInfo],
        ),
        "includes_deps": attr.label_list(providers = [CcInfo]),
        "linker_script": attr.label(allow_single_file = True),
        "sdk_version": attr.string(),
        "min_sdk_version": attr.string(),
        "crt": attr.bool(default = False),
        "package_name": attr.string(
            mandatory = True,
            doc = "Just the path to the target package. Used by transitions.",
        ),
        "_android_product_variables": attr.label(
            default = Label("//build/bazel/product_config:product_variables_for_attributes"),
            providers = [platform_common.TemplateVariableInfo],
        ),
        "_apex_min_sdk_version": attr.label(
            default = "//build/bazel/rules/apex:min_sdk_version",
        ),
        "_allowlist_function_transition": attr.label(
            default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
        ),
    },
    toolchains = ["//prebuilts/clang/host/linux-x86:nocrt_toolchain"],
    fragments = ["cpp"],
)

def cc_object(
        name,
        copts = [],
        hdrs = [],
        asflags = [],
        linkopts = [],
        srcs = [],
        srcs_as = [],
        objs = [],
        deps = [],
        native_bridge_supported = False,  # TODO: not supported yet. @unused
        stl = "",
        system_dynamic_deps = None,
        sdk_version = "",
        min_sdk_version = "",
        **kwargs):
    "Build macro to correspond with the cc_object Soong module."

    if system_dynamic_deps == None:
        system_dynamic_deps = system_dynamic_deps_defaults

    stl_info = stl_info_from_attr(stl, False)
    linkopts = linkopts + stl_info.linkopts
    copts = copts + stl_info.cppflags

    _cc_object(
        name = name,
        hdrs = hdrs,
        asflags = asflags,
        copts = _CC_OBJECT_COPTS + copts,
        linkopts = linkopts,
        # TODO(b/261996812): we shouldn't need to have both srcs and srcs_as as inputs here
        srcs = srcs,
        srcs_as = srcs_as,
        objs = objs,
        includes_deps = stl_info.static_deps + stl_info.shared_deps + system_dynamic_deps + deps,
        sdk_version = sdk_version,
        min_sdk_version = min_sdk_version,
        package_name = native.package_name(),
        **kwargs
    )