blob: 00a77164ad954019ca4ec7d5a4b4b7c106ac3cd3 [file] [log] [blame]
#!/usr/bin/env python3
# Copyright 2022 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.
""" An internal set of tools for creating embedded CC targets. """
load("@rules_cc//cc:action_names.bzl", "C_COMPILE_ACTION_NAME")
load("@rules_cc//cc:toolchain_utils.bzl", "find_cpp_toolchain")
DEBUGGING = [
"-g",
]
# Standard compiler flags to reduce output binary size.
REDUCED_SIZE_COPTS = [
"-fno-common",
"-fno-exceptions",
"-ffunction-sections",
"-fdata-sections",
]
STRICT_WARNINGS_COPTS = [
"-Wall",
"-Wextra",
# Make all warnings errors, except for the exemptions below.
"-Werror",
"-Wno-error=cpp", # preprocessor #warning statement
"-Wno-error=deprecated-declarations", # [[deprecated]] attribute
]
CPP17_COPTS = [
"-std=c++17",
"-fno-rtti",
"-Wnon-virtual-dtor",
# Allow uses of the register keyword, which may appear in C headers.
"-Wno-register",
]
DISABLE_PENDING_WORKAROUND_COPTS = [
"-Wno-private-header",
]
PW_DEFAULT_COPTS = (
DEBUGGING +
REDUCED_SIZE_COPTS +
STRICT_WARNINGS_COPTS +
DISABLE_PENDING_WORKAROUND_COPTS
)
KYTHE_COPTS = [
"-Wno-unknown-warning-option",
]
PW_DEFAULT_LINKOPTS = []
def add_defaults(kwargs):
"""Adds default arguments suitable for both C and C++ code to kwargs.
Args:
kwargs: cc_* arguments to be modified.
"""
copts = PW_DEFAULT_COPTS + kwargs.get("copts", [])
kwargs["copts"] = select({
"@pigweed//pw_build:kythe": copts + KYTHE_COPTS,
"//conditions:default": copts,
})
kwargs["linkopts"] = kwargs.get("linkopts", []) + PW_DEFAULT_LINKOPTS
# Set linkstatic to avoid building .so files.
kwargs["linkstatic"] = True
kwargs.setdefault("features", [])
# Crosstool--adding this line to features disables header modules, which
# don't work with -fno-rtti. Note: this is not a command-line argument,
# it's "minus use_header_modules".
kwargs["features"].append("-use_header_modules")
def default_cc_and_c_kwargs(kwargs):
"""Splits kwargs into C and C++ arguments adding defaults.
Args:
kwargs: cc_* arguments to be modified.
Returns:
A tuple of (cc_cxx_kwargs cc_c_kwargs)
"""
add_defaults(kwargs)
kwargs.setdefault("srcs", [])
cc = dict(kwargs.items())
cc["srcs"] = [src for src in kwargs["srcs"] if not src.endswith(".c")]
cc["copts"] = cc["copts"] + CPP17_COPTS
c_srcs = [src for src in kwargs["srcs"] if src.endswith(".c")]
if c_srcs:
c = dict(kwargs.items())
c["name"] += "_c"
c["srcs"] = c_srcs + [src for src in kwargs["srcs"] if src.endswith(".h")]
cc["deps"] = cc.get("deps", []) + [":" + c["name"]]
return cc, c
return cc, None
def add_cc_and_c_targets(target, kwargs): # buildifier: disable=unnamed-macro
"""Splits target into C and C++ targets adding defaults.
Args:
target: cc_* target to be split.
kwargs: cc_* arguments to be modified.
"""
cc_kwargs, c_kwargs = default_cc_and_c_kwargs(kwargs)
if c_kwargs:
native.cc_library(**c_kwargs)
target(**cc_kwargs)
def has_pw_assert_dep(deps):
"""Checks if the given deps contain a pw_assert dependency
Args:
deps: List of dependencies
Returns:
True if the list contains a pw_assert dependency.
"""
pw_assert_targets = ["//pw_assert", "//pw_assert:pw_assert"]
pw_assert_targets.append(["@pigweed" + t for t in pw_assert_targets])
for dep in deps:
if dep in pw_assert_targets:
return True
return False
def _preprocess_linker_script_impl(ctx):
cc_toolchain = find_cpp_toolchain(ctx)
output_script = ctx.actions.declare_file(ctx.label.name + ".ld")
feature_configuration = cc_common.configure_features(
ctx = ctx,
cc_toolchain = cc_toolchain,
requested_features = ctx.features,
unsupported_features = ctx.disabled_features,
)
cxx_compiler_path = cc_common.get_tool_for_action(
feature_configuration = feature_configuration,
action_name = C_COMPILE_ACTION_NAME,
)
c_compile_variables = cc_common.create_compile_variables(
feature_configuration = feature_configuration,
cc_toolchain = cc_toolchain,
user_compile_flags = ctx.fragments.cpp.copts + ctx.fragments.cpp.conlyopts,
)
env = cc_common.get_environment_variables(
feature_configuration = feature_configuration,
action_name = C_COMPILE_ACTION_NAME,
variables = c_compile_variables,
)
ctx.actions.run(
outputs = [output_script],
inputs = depset(
[ctx.file.linker_script],
transitive = [cc_toolchain.all_files],
),
executable = cxx_compiler_path,
arguments = [
"-E",
"-P",
"-xc",
ctx.file.linker_script.short_path,
"-o",
output_script.path,
] + [
"-D" + d
for d in ctx.attr.defines
] + ctx.attr.copts,
env = env,
)
return [DefaultInfo(files = depset([output_script]))]
pw_linker_script = rule(
_preprocess_linker_script_impl,
attrs = {
"copts": attr.string_list(doc = "C compile options."),
"defines": attr.string_list(doc = "C preprocessor defines."),
"linker_script": attr.label(
mandatory = True,
allow_single_file = True,
doc = "Linker script to preprocess.",
),
"_cc_toolchain": attr.label(default = Label("@bazel_tools//tools/cpp:current_cc_toolchain")),
},
toolchains = ["@bazel_tools//tools/cpp:toolchain_type"],
fragments = ["cpp"],
)