carbon-lang/.bazelrc

# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
# Exceptions. See /LICENSE for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

# Support running clang-tidy with:
#   bazel build --config=clang-tidy -k //...
# See: https://github.com/erenon/bazel_clang_tidy
build:clang-tidy --aspects @bazel_clang_tidy//clang_tidy:clang_tidy.bzl%clang_tidy_aspect
build:clang-tidy --output_groups=report
build:clang-tidy --@bazel_clang_tidy//:clang_tidy_config=//:clang_tidy_config

# This warning seems to incorrectly fire in this build configuration, despite
# not firing in our normal builds.
build:clang-tidy --copt=-Wno-unknown-pragmas

# Default to using a disk cache to minimize re-building LLVM and Clang which we
# try to avoid updating too frequently to minimize rebuild cost. The location
# here can be overridden in the user configuration where needed.
#
# Note that this cache will grow without bound currently. You should
# periodically run the `scripts/clean_disk_cache.sh` script or some equivalent.
# https://github.com/bazelbuild/bazel/issues/5139 tracks fixing this in Bazel.
build --disk_cache=~/.cache/carbon-lang-build-cache

# Enable some safety when using the build cache, likely to be defaulted in
# future Bazel releases.
build --experimental_guard_against_concurrent_changes

# Disable warnings for all external compilations. These involve code that isn't
# developed as part of Carbon and may be difficult or impossible to patch, so
# warnings aren't likely to be actionable.
build --per_file_copt=external/.*\.(c|cc|cpp|cxx)$@-w
build --host_per_file_copt=external/.*\.(c|cc|cpp|cxx)$@-w

# The `rules_treesitter` synthesized libraries don't allow us to inject flags,
# and compile generated code where we can't fix warnings.
build --per_file_copt=utils/treesitter/_treesitter.tree_sitter/.*\.c$@-w
build --host_per_file_copt=utils/treesitter/_treesitter.tree_sitter/.*\.c$@-w

# The `cc_proto_library` rule doesn't allow providing `copts`:
# https://github.com/bazelbuild/bazel/issues/22610
#
# We unfortunately need to work around issues with `-Wmissing-prototypes` in
# generated protobuf code, so pass the `copt` manually here. The warning issue
# is likely part of:
# https://github.com/llvm/llvm-project/issues/94138
build --per_file_copt=.*\.pb\.cc$@-Wno-missing-prototypes
build --host_per_file_copt=.*\.pb\.cc$@-Wno-missing-prototypes

# Default dynamic linking to off. While this can help build performance in some
# edge cases with very large linked executables and a slow linker, between using
# fast linkers on all platforms (LLD and the Apple linker), as well as having
# relatively few such executables, shared objects simply waste too much space in
# our builds.
build --dynamic_mode=off

# Always compile PIC code. There are few if any disadvantages on the platforms
# and architectures we care about and it avoids the need to compile files twice.
build --force_pic

# Completely disable Bazel's automatic stripping of debug information. Removing
# that information causes unhelpful backtraces from unittest failures and other
# crashes. Optimized builds already avoid using debug information by default.
build --strip=never

# Enable Abseil for GoogleTest.
build --define=absl=1

# Configuration for enabling Address Sanitizer. Note that this is enabled by
# default for fastbuild. The config is provided to enable ASan even in
# optimized or other build configurations.
build:asan --features=asan

# Configuration for enabling LibFuzzer (along with ASan).
build:fuzzer --features=fuzzer

# Always allow tests to symbolize themselves with whatever `llvm-symbolize` is
# in the users environment.
build --test_env=ASAN_SYMBOLIZER_PATH

# Force actions to have a UTF-8 language encoding.
# TODO: Need to investigate what this should be on Windows, but at least for
# Linux and macOS this seems strictly better than the Bazel default of just
# `en_US`.
build --action_env=LANG=en_US.UTF-8

# Allow users to override any of the flags desired by importing a user-specific
# RC file here if present.
try-import %workspace%/user.bazelrc