.bazelrc

# Enables picking up host-OS specific config, i.e. adds support for the following:
# `build:[ linux | macos | windows | freebsd | openbsd ]`
common --enable_platform_specific_config

# TODO(parkmycar): Migrate to Bzlmod.
#
# Note: We are not yet using Bzlmod because there are parts of the ecosystem
# that haven't yet migrated to it.
common --noenable_bzlmod

# Required for remote caching to be effective.
#
# Otherwise Bazel will passthrough the current system's PATH in the execution
# environment, which differs between systems and thus breaks remote caching.
build --incompatible_strict_action_env
# Prevent actions in the sandbox from accessing the network.
#
# TODO(parkmycar): `prof-http`s build script downloads resources from npm.
#build --sandbox_default_allow_network=false

# Bazel provides the macOS 14.5 SDK as the sysroot, we also set the minimum
# version to prevent breaking the remote cache across developer machines.
common --copt=-mmacosx-version-min=14.0
common --linkopt=-mmacosx-version-min=14.0
common --macos_sdk_version=14.0
# Note(parkmycar): Ideally we would error on unused command line arguments, but
# trying to constrain the above arguments to just macos doesn't seem to work.
common --copt=-Wno-unused-command-line-argument
common --linkopt=-Wno-unused-command-line-argument

# Config for building protobuf.
build --copt=-Wno-error=deprecated-declarations

# Required to stamp our development builds with the current git hash.
#
# This script gets run before every build, see the script for more info.
build:release-stamp --stamp --workspace_status_command "python3 misc/bazel/build-info/workspace_status.py"

# Output all test output by default, this makes it most like cargo.
#
# Note: We used to have 'stream' here, but that forces Bazel to serialize test execution.
build --test_output=all
# Environment variables to pass through to the test runner. These can impact
# remote cache hits, so add them sparingly.
#
# TODO(parkmycar): Switch over to using `env_inherit` on `rust_test` once that's stable.
# <https://github.com/bazelbuild/rules_rust/pull/2809>
build --test_env=COCKROACH_URL

# Allows spaces to in filenames, without this Rust Doc tests fail to build.
build:macos --experimental_inprocess_symlink_creation
# Tracks stashed sandboxes in-memory so it uses less I/O on reuse.
#
# Bazel's sandbox performance on macOS doesn't scale very well, see: <https://github.com/bazelbuild/bazel/issues/8230>
build --experimental_inmemory_sandbox_stashes

# Always have Bazel output why it rebuilt something, should make debugging builds easier.
#
# TODO(parkmycar): Enable this under a "debug" or "verbose"
# common --explain=bazel-explain.log
# common --verbose_explanations

# Compress any artifacts larger than 2MiB with zstd.
common --remote_cache_compression
common --experimental_remote_cache_compression_threshold=2097152
# Memoizes merkle tree calculations to improve the remote cache hit checking speed.
common --experimental_remote_merkle_tree_cache
# Number of merkle trees to memoize (default 1000).
common --experimental_remote_merkle_tree_cache_size=5000
# Don't make the user wait for uploading artifacts to complete, finish it in the background.
common --bes_upload_mode=fully_async
# Make sure any local disk cache stays within a reasonable size.
common --experimental_disk_cache_gc_max_size=80G
common --experimental_disk_cache_gc_max_age=14d

# Tells `xz` to use all available cores.
action_env=XZ_OPT=-T0

#
# Config when running Bazel from a script.
#
# Silence most UI output since it's noisy.
run:script --ui_event_filters=-info,-stdout,-stderr --noshow_progress

# LLVM's libc++ has different assertion modes which can be configured to catch
# undefined behavior. See: <https://libcxx.llvm.org/Hardening.html>
build:debug --cxxopt="-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG"
build:debug --host_cxxopt="-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG"
build:debug --@rules_rust//:extra_rustc_flag="-Csplit-debuginfo=unpacked"

#
# Debug Info Configuration
#

# TODO(parkmycar): Enable this for macOS. `toolchains_llvm` defaults to ld64 which
# doesn't support zlib compression.
build:linux --linkopt="-Wl,--compress-debug-sections=zlib"
build:linux --@rules_rust//:extra_rustc_flag="-Clink-arg=-Wl,--compress-debug-sections=zlib"
# Specifying "-O2" uses level 6 zlib compression.
build:linux --linkopt="-Wl,-O2"
build:linux --@rules_rust//:extra_rustc_flag="-Clink-arg=-Wl,-O2"
build:linux --copt="-gz=zlib"

# Match the DWARF version used by Rust
#
# See: <https://doc.rust-lang.org/stable/unstable-book/compiler-flags/dwarf-version.html>
build:linux --copt="-gdwarf-4"
build:linux --linkopt="-gdwarf-4"
build:macos --copt="-gdwarf-2"
build:macos --linkopt="-gdwarf-2"

# Emit full debug info, allowing us to easily analyze core dumps from staging
# (and, in an emergency, also prod).
build:debuginfo-full --@rules_rust//:extra_rustc_flag=-Cdebuginfo=2
build:debuginfo-full --copt=-g2
build:debuginfo-full --strip=never
build:debuginfo-full --@rules_rust//:extra_rustc_flag=-Cstrip=none

build:debuginfo-limited --@rules_rust//:extra_rustc_flag=-Cdebuginfo=line-tables-only
build:debuginfo-limited --copt=-gline-tables-only
build:debuginfo-limited --strip=never
build:debuginfo-limited --@rules_rust//:extra_rustc_flag=-Cstrip=none

build:debuginfo-none --@rules_rust//:extra_rustc_flag=-Cdebuginfo=0
build:debuginfo-none --copt=-g0
build:debuginfo-none --strip=always
build:debuginfo-none --@rules_rust//:extra_rustc_flag=-Cstrip=symbols

#
# Common Build Configuration
#
build --linkopt="-fuse-ld=lld"
build --@rules_rust//:extra_rustc_flag="-Clink-arg=-fuse-ld=lld"
build --@rules_rust//:extra_rustc_flag="-Csymbol-mangling-version=v0"
# We use 64 because it's enough to totally saturate a CI builder so our builds
# are as fast as possible, and it's less than the default of 256 used with
# Cargo when incremental compilation is enabled.
build --@rules_rust//:extra_rustc_flag="-Ccodegen-units=64"
# Enabling pipelined builds allows dependent libraries to begin compiling with
# just `.rmeta` instead of the full `.rlib`.
build --@rules_rust//rust/settings:pipelined_compilation=True

# `cargo check` like config, still experimental!
#
# Ignores all outputs other than `.rmeta`, requires pipelied_compilation to be enabled!
build:check --output_groups=build_metadata

# CI Build Configuration
#
# Note: This shouldn't change any config of the built binary, just the way it
# gets built.
#
# `/dev/shm` is a RAM backed temporary filesystem, it should speedup sandbox creation.
build:ci --sandbox_base=/dev/shm
# Always enable verbose failures in CI, makes it easier to debug failures.
build:ci --verbose_failures

# Release Build Configuration
#
build:release --cxxopt=-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_FAST
build:release --copt=-O3
build:release --copt=-DNDEBUG
build:release --compilation_mode=opt

# We only enable Link Time Optimization for CI builds and not local release builds.
build:release-lto --copt=-flto=thin
build:release-lto --linkopt=-flto=thin
build:release-lto --@rules_rust//:extra_rustc_flag=-Clto=thin

# Builds from `main` or tagged builds.
#
# Note: We don't use a ramdisk for tagged builds because the full debuginfo is
# too large and we OOD/OOM.
build:release-tagged --config=release --config=release-lto --config=release-stamp --config=debuginfo-full
# PRs in CI.
#
# Not doing a full stamp nor omitting full debug info, greatly speeds up compile times.
build:release-dev --config=release --config=release-lto --config=debuginfo-limited

# "Optimized" Build.
#
# Provides both reasonably fast compile times and runtimes.
build:optimized --compilation_mode=opt
build:optimized --cxxopt=-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_FAST
build:optimized --copt=-O2
build:optimized --copt=-DNDEBUG

build:optimized --config=debuginfo-none

build:optimized --copt=-fno-lto
build:optimized --linkopt=-fno-lto
build:optimized --@rules_rust//:extra_rustc_flag=-Clto=off
build:optimized --@rules_rust//:extra_rustc_flag=-Cembed-bitcode=no

# Build with the Rust Nightly Toolchain
build:rust-nightly --@rules_rust//rust/toolchain/channel=nightly

# Cross Language LTO
#
# <https://blog.llvm.org/2019/09/closing-gap-cross-language-lto-between.html>
#
# TODO(parkmycar): Re-enable these. They eiter cause a compilation failure because of
# missing object files, or (seemingly) makes the number of codegen units 1 which compiles
# way too slow.
#build:release --@rules_rust//:extra_rustc_flag="-Clinker-plugin-lto"
#build:linux --@rules_rust//rust/settings:experimental_use_cc_common_link=True

# This 'features' option comes from the `unix_cc_toolchain_config` in Bazel core and sets all the
# right flags.
#
# See: <https://github.com/bazelbuild/bazel/blob/master/tools/cpp/unix_cc_toolchain_config.bzl>
#build:release --features=thin_lto