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

# Ensure all builds have Carbon's workspace status attached. We have carefully
# factored the stamping done by this to avoid excessive build performance impact
# and so enable stamping with it by default. CI and systems especially dependent
# on caching should explicitly use `--nostamp`.
build --workspace_status_command=./scripts/workspace_status.py
build --stamp

# Provide aliases for configuring the release and pre-release version being
# built. For documentation of these flags, see //bazel/version/BUILD.
build --flag_alias=release=//bazel/version:release
build --flag_alias=pre_release=//bazel/version:pre_release
build --flag_alias=rc_number=//bazel/version:rc_number
build --flag_alias=nightly_date=//bazel/version:nightly_date

# 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
build:clang-tidy --action_env=PATH --host_action_env=PATH

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

# Provide an alias for controlling the `carbon_*` Bazel rules' configuration. We
# enable use of the target config here to make our build and tests more
# efficient, see the documentation in //bazel/carbon_rules/BUILD for details.
build --flag_alias=use_target_config_carbon_rules=//bazel/carbon_rules:use_target_config_carbon_rules
build --use_target_config_carbon_rules

# 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

# Used by clang_configuration.bzl.
build --action_env=CC --host_action_env=CC
build --action_env=CMAKE_SYSROOT --host_action_env=CMAKE_SYSROOT

# 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

# 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

# Enable TCMalloc on Linux in optimized builds.
build --custom_malloc=//bazel/malloc:tcmalloc_if_linux_opt

# 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. Note that ASan and TCMalloc are
# incompatible so this explicitly forces the system malloc.
build:asan --features=asan
build:asan --custom_malloc=@bazel_tools//tools/cpp:malloc

# 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 per-platform configuration.
build --enable_platform_specific_config

# Enable libpfm for google_benchmark on Linux only.
build:linux --define=pfm=1

# Enable split debug info on Linux, which is significantly more space efficient
# and should work well with modern debuggers. Note that this is Linux specific
# as macOS has its own approach that is always partially but not completely
# split.
#
# Note: if using GDB, see documentation to get that working:
# https://docs.carbon-lang.dev/docs/project/contribution_tools.html#debugging-with-gdb-instead-of-lldb
#
# TODO: Bazel has a bug where it doesn't manage dwo files in the cache correctly.
# build:linux --fission=yes

# Disables `actions.declare_symlink`. Done for cross-environment support.
build --allow_unresolved_symlinks=false

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

# TODO: WORKSPACE will be removed in bazel 9, should finish moving off.
common --enable_workspace

# The version of treesitter rules we're using depends on empty globs.
# TODO: Look at the different rules in the registry.
common --incompatible_disallow_empty_glob=false

# TODO: Enable as many incompatible flags as we can, per
# https://bazel.build/release/backward-compatibility. To get the latest list,
# using `bazelisk --migrate build //...` will help.
common --incompatible_strict_action_env

# This excludes things like rules_android to reduce warnings.
# TODO: Disable this completely.
common --incompatible_autoload_externally=+@rules_java,+@rules_python,+@rules_shell