common --enable_platform_specific_config

build --verbose_failures

build --build_tag_filters=-off-by-default,-requires-container-engine

# block network access by default

build --nosandbox_default_allow_network

test --test_tag_filters=-off-by-default,-requires-fuzzilli,-requires-container-engine

test:asan --test_tag_filters=-off-by-default,-no-asan,-requires-fuzzilli,-requires-container-engine

# exclude enormous tests by default

build --test_size_filters=-enormous

# Don't run tests that set up TCP sockets in parallel since they may try to use the same ports. This

# is less restrictive than marking such tests as "exclusive" since we can still run unrelated tests

# at the same time.

test --local_resources=socket=1

# use lower test timeouts: https://bazel.build/reference/test-encyclopedia#role-test-runner

# corresponds to small,medium,large,enormous tests (medium is default)

build --test_timeout=3,15,60,240

# As part of starlarkification, Bazel 8 and 9 remove a number of rules which now need to be imported

# from other repositories. In the long term, load() statements will be needed to import these rules.

# For now, we can still autoload the affected repositories when needed. Do this only for a remaining

# protobuf component and rules_cc (needed with Bazel 9).

# cc_test is only included because of highway; remove once they include cc_test properly.

common --incompatible_autoload_externally="+ProtoInfo,+cc_binary,+cc_library,+cc_test"

# TODO(cleanup): Bazel 9 sets this by default, which breaks the macOS-cross build. Fix and re-enable.

common --@bazel_tools//tools/test:incompatible_use_default_test_toolchain=False

# Enable proto toolchain resolution to use prebuilt protoc (starting with protobuf v34.0). Will be

# the default starting with Bazel 10.

common --incompatible_enable_proto_toolchain_resolution

# bazel7 enables Build without the Bytes (BwoB) by default. This significantly speeds up builds

# using the remote cache since less data needs to be fetched.

# Note that we use remote_download_minimal for test builds, which avoids fetching build outputs

# where possible. While several previous BwoB bugs have been fixed, this is slower than it could be

# due to https://github.com/bazelbuild/bazel/issues/20576.

# Import CI-specific configuration. As the amount of custom configuration settings we use grows,

# consider moving more flags out to separate files.

import %workspace%/build/ci.bazelrc

import %workspace%/build/rust_lint.bazelrc

import %workspace%/build/tools/clang_tidy/clang_tidy.bazelrc

# Continue building locally when remote cache entries fail to materialize

build --incompatible_remote_local_fallback_for_remote_cache

# Use -isystem for cc_library includes attribute – this prevents warnings for misbehaving external

# code. Applies to both Linux and macOS via the shared `:unix` config (see the

# `build:linux --config=unix` / `build:macos --config=unix` lines below).

build:unix --features=external_include_paths --host_features=external_include_paths

# Forward compatibility with future Bazel versions:

# Disable deprecated cfg = "host" Bazel rule setting. Blocked on perfetto.

# common --incompatible_disable_starlark_host_transitions

# Globally disable the "diabolic behavior" of implicit __init__.py creation (https://github.com/bazel-contrib/rules_python/issues/2945)

common --incompatible_default_to_explicit_init_py

# Our dependencies (ICU, zlib, etc.) produce a lot of these warnings, so we disable them.

build --per_file_copt='external@-Wno-error'

build --per_file_copt='external@-Wno-suggest-override'

build --per_file_copt='external/.*v8@-Wno-unused-function'

build --per_file_copt='external/zlib@-Wno-deprecated-non-prototype'

build --host_per_file_copt='external/zlib@-Wno-deprecated-non-prototype'

build --per_file_copt=external/protobuf@-Wno-deprecated-declarations

build --host_per_file_copt=external/protobuf@-Wno-deprecated-declarations

build --per_file_copt=external/protobuf@-Wno-deprecated-this-capture

build --host_per_file_copt=external/protobuf@-Wno-deprecated-this-capture

# opt in to capnp deprecation warnings about trying to attach to a refcounted object

build --cxxopt=-DKJ_WARN_REFCOUNTED_ATTACH=1

# TODO(cleanup): Causes warnings with LLVM20, fix and enable again

build --copt=-Wno-nontrivial-memaccess

# Unconditionally optimize V8 heap.cc on macOS – when optimization or inlining are disabled, this

# file appears to cause segfaults at workerd startup on macOS.

# TODO(cleanup): Investigate why this happens, our patches do not modify heap.cc itself so the bug

# might be introduced through a header included in heap.cc, through the Bazel build configuration or

# a bug in Apple LLVM.

build:macos --per_file_copt=v8/src/heap/heap.cc@-O3

# The macOS apple_support toolchain sets -DDEBUG for fastbuild, unlike the Linux toolchain. This is

# unhelpful for compile speeds and test performance, and may cause compile errors based on V8 DCHECK

# macros that reference symbols only available with V8_VERIFY_WRITE_BARRIERS (a debug-only define),

# causing compile errors. Undefine DEBUG to match Linux behavior.

build:macos --copt=-UDEBUG

# Increasing the optimization level of V8 significantly speeds up tests using V8 a lot, especially

# python tests. This is useful for both CI and local development and enabled by default, but still

# kept in a separate configuration to make it easy to disable.

build:v8-codegen-opt --per_file_copt=v8/src@-O3

# V8 is heavily using absl for hashing now, optimize it too.

build:v8-codegen-opt --per_file_copt=external/abseil-cpp@-O3

# zlib and tcmalloc (for Linux) are also CPU-intensive, optimize them too.

build:v8-codegen-opt --per_file_copt=external/tcmalloc@-O3

build:v8-codegen-opt --per_file_copt=external/zlib@-O3

# BoringSSL is CPU-intensive for crypto tests, optimize it too.

build:v8-codegen-opt --per_file_copt=external/boringssl@-O3

# simdutf is used for fast string encoding/decoding

build:v8-codegen-opt --per_file_copt=external/+http+simdutf@-O3

# ICU and perfetto are generally updated with V8 and rarely need to be updated, optimize them too.

build:v8-codegen-opt --per_file_copt=external/.*com_googlesource_chromium_icu@-O3

build:v8-codegen-opt --per_file_copt=external/perfetto@-O3

build:v8-codegen-opt-windows --per_file_copt=v8/src@/O2,/clang:-O3

build:v8-codegen-opt-windows --per_file_copt=external/abseil-cpp@/O2,/clang:-O3

build:v8-codegen-opt-windows --per_file_copt=external/zlib@/O2,/clang:-O3

build:v8-codegen-opt-windows --per_file_copt=external/boringssl@/O2,/clang:-O3

build:v8-codegen-opt-windows --per_file_copt=external/+http+simdutf@/O2,/clang:-O3

build:v8-codegen-opt-windows --per_file_copt=external/.*com_googlesource_chromium_icu@/O2,/clang:-O3

build:v8-codegen-opt-windows --per_file_copt=external/perfetto@/O2,/clang:-O3

build:unix --config=v8-codegen-opt

build:windows --config=v8-codegen-opt-windows

# In Google projects, exceptions are not used as a rule. Disabling them is more consistent with the

# canonical V8 build and improves code size. Paths are adjusted for bzlmod mangling – V8 and ICU use

# a wildcard for this as the prefix is some variation of +_repo_rules3+ where the number can change

# when refactoring MODULE.bazel – setting this directly would be too brittle

build:unix --per_file_copt=external/abseil-cpp@-fno-exceptions

build:unix --per_file_copt=external/protobuf@-fno-exceptions

build:unix --per_file_copt=external/tcmalloc@-fno-exceptions

build:unix --per_file_copt=external/.*com_googlesource_chromium_icu@-fno-exceptions

build:unix --per_file_copt=external/perfetto@-fno-exceptions

build:unix --per_file_copt=external/boringssl@-fno-exceptions

build:unix --per_file_copt=external/.*v8@-fno-exceptions

build:unix --per_file_copt=external/ada-url@-fno-exceptions

build:unix --per_file_copt=external/+http+simdutf@-fno-exceptions

build:windows --per_file_copt=external/abseil-cpp@/clang:-fno-exceptions

build:windows --per_file_copt=external/protobuf@/clang:-fno-exceptions

build:windows --per_file_copt=external/tcmalloc@/clang:-fno-exceptions

build:windows --per_file_copt=external/.*com_googlesource_chromium_icu@/clang:-fno-exceptions

build:windows --per_file_copt=external/perfetto@/clang:-fno-exceptions

build:windows --per_file_copt=external/boringssl@/clang:-fno-exceptions

build:windows --per_file_copt=external/.*v8@/clang:-fno-exceptions

build:windows --per_file_copt=external/ada-url@/clang:-fno-exceptions

build:windows --per_file_copt=external/+http+simdutf@/clang:-fno-exceptions

# V8 torque is an exception from this policy, see v8 BUILD.gn.

build:unix --per_file_copt=external/.*v8/src/torque@-fexceptions

build:windows --per_file_copt=external/.*v8/src/torque@/clang:-fexceptions

# Limit transitive header includes within libc++. This improves compliance with IWYU, helps avoid

# errors with downstream projects that implicitly define this already and reduces total include size.

https://libcxx.llvm.org/DesignDocs/HeaderRemovalPolicy.html

build:unix --cxxopt=-D_LIBCPP_REMOVE_TRANSITIVE_INCLUDES --host_cxxopt=-D_LIBCPP_REMOVE_TRANSITIVE_INCLUDES

# Do not enable libc++ ABI tags. This makes mangled symbol names and thus include overhead and code

# size slightly smaller and is safe as long as we don't link with several copies of libc++.

build:unix --cxxopt=-D_LIBCPP_NO_ABI_TAG --host_cxxopt=-D_LIBCPP_NO_ABI_TAG

# Disable the experimental (and currently incomplete) parallel STL implementation as with

# downstream, this reduces the include overhead for <algorithm>.

build:unix --cxxopt=-D_LIBCPP_HAS_NO_INCOMPLETE_PSTL --host_cxxopt=-D_LIBCPP_HAS_NO_INCOMPLETE_PSTL

# V8 redefines the _WIN32_WINNT set by bazel, disable warnings for redefined macros. Since V8 uses

# a global define for this, we need to apply it for everything.

# TODO(cleanup): Patch upstream V8 to use local_defines for this instead.

build:windows --copt='-Wno-macro-redefined'

build:windows --host_copt='-Wno-macro-redefined'

# typescript configuration

# do more correct type checking

common --@aspect_rules_ts//ts:skipLibCheck=honor_tsconfig

# Use "tsc" as the transpiler when ts_project has no `transpiler` set.

common --@aspect_rules_ts//ts:default_to_tsc_transpiler

# optimized LTO build.

build:thin-lto --config=opt

build:thin-lto --copt='-flto=thin'

build:thin-lto --linkopt='-flto=thin'

# configuration used for performance profiling

build:profile --config=thin-lto

build:profile --copt="-fno-omit-frame-pointer" --copt="-mno-omit-leaf-frame-pointer"

build:profile --config=limited-dbg-info

build:profile --strip=never

# configuration used for performance benchmarking is the same as profiling for consistency

build:benchmark --config=profile

# Define a debug config which is primarily intended for local development.

build:debug -c dbg

# Using simple template names saves around 5% of binary size of workerd.

build:unix --cxxopt='-gsimple-template-names' --host_cxxopt='-gsimple-template-names'

# Enable hidden visibility for inline functions. This can cause problems when comparing pointers to

# inline functions across shared library boundaries, but this is unlikely to be done anywhere

# within workerd, V8 explicitly supports hidden visibility.

build:unix --cxxopt='-fvisibility-inlines-hidden' --host_cxxopt='-fvisibility-inlines-hidden'

# Define a config mode which is fastbuild but with basic debug info.

build:fastdbg -c fastbuild

build:fastdbg --config=limited-dbg-info

build:fastdbg --config=rust-debug

build:fastdbg --strip=never

build:fastdbg --//:dead_strip=False

# provide a limited amount of debug info, sufficient for qualified stack traces.

build:limited-dbg-info --copt='-g1' --copt="-fdebug-info-for-profiling"

# Miscellaneous platform-independent options

build --@capnp-cpp//src/kj:openssl=True --@capnp-cpp//src/kj:zlib=True --@capnp-cpp//src/kj:brotli=True

build --@capnp-cpp//src/capnp:gen_rust=True

# always have KJ_IREQUIRE checks enabled, this matches workers production.

build --@capnp-cpp//src/kj:kj_enable_irequire=True

# overriden in config=opt

build --@capnp-cpp//src/kj:debug_memory=True

build --cxxopt="-fbracket-depth=512" --host_cxxopt="-fbracket-depth=512"

# Additional Rust flags (see https://doc.rust-lang.org/rustc/codegen-options/index.html)

# Need to disable debug-assertions for fastbuild, should be off automatically for opt.

# Using extra_rustc_flag for non-exec flags so they can be overwritten selectively.

build --@rules_rust//:extra_rustc_flag=-Cdebug-assertions=n

build --@rules_rust//:extra_exec_rustc_flags=-Cdebug-assertions=n

build --@rules_rust//:rustfmt.toml=//src/rust:rustfmt.toml

# We default to not enabling debug assertions and unwinding for Rust. For debug builds this is not

# the right setting, but unfortunately we can't set that directly.

build:rust-debug --@rules_rust//:extra_rustc_flag=-Cdebug-assertions=y

# Use the equivalent of -g/-g2 for Rust here, this is necessary to get qualified stack traces while

# -Zdebug-info-for-profiling is unavailable. Unlike gcc/clang, Rust defaults to -g3 otherwise.

build:rust-debug --@rules_rust//:extra_rustc_flag=-Cdebuginfo=1

build:rust-debug --@rules_rust//:extra_rustc_flag=-Cstrip=none

# Adding -C lto=thin here would improve binary size significantly – disable it for now due to

# compile errors and wrong code generation when bazel and rust use different LLVM versions.

build:thin-lto --@rules_rust//:extra_rustc_flag=-Ccodegen-units=1

# common sanitizers options

build:sanitizer-common --@workerd//src/workerd/server:use_tcmalloc=False

build:sanitizer-common --copt="-fsanitize-link-c++-runtime" --linkopt="-fsanitize-link-c++-runtime"

build:sanitizer-common --copt="-Og"

build:sanitizer-common --copt="-g" --strip=never

build:sanitizer-common --copt="-fno-optimize-sibling-calls"

build:sanitizer-common --copt="-fno-omit-frame-pointer" --copt="-mno-omit-leaf-frame-pointer"

# address sanitizer (https://github.com/google/sanitizers/wiki/AddressSanitizer)

build:asan --config=sanitizer-common

build:asan --copt="-fsanitize=address" --linkopt="-fsanitize=address"

build:asan --test_env=ASAN_OPTIONS=abort_on_error=true

build:asan --test_env=KJ_CLEAN_SHUTDOWN=1

# Enable ASan, LSan support in V8

build:asan --copt="-DV8_USE_ADDRESS_SANITIZER"

build:asan --per_file_copt='external/.*v8@-DADDRESS_SANITIZER,-DLEAK_SANITIZER'

# fuzzilli (https://github.com/googleprojectzero/fuzzilli/)

build:fuzzilli --config=asan

build:fuzzilli --copt="-DWORKERD_FUZZILLI"

build:fuzzilli --linkopt="-DWORKERD_FUZZILLI"

build:fuzzilli --copt="-fsanitize-coverage=trace-pc-guard"

build:fuzzilli --linkopt="-fsanitize-coverage=trace-pc-guard"

build:fuzzilli --linkopt="-static-libasan"

# Set ASan/UBSan options globally to abort on error (raise SIGABRT) for proper Fuzzilli crash detection

build:fuzzilli --action_env=ASAN_OPTIONS=abort_on_error=1:symbolize=false

build:fuzzilli --action_env=UBSAN_OPTIONS=abort_on_error=1:symbolize=false

# Override test filters to include requires-fuzzilli tests (inherits asan's -no-asan filter)

test:fuzzilli --test_tag_filters=-off-by-default

#

# Linux and macOS

#

build:unix --workspace_status_command=./tools/unix/workspace-status.sh

build:unix --cxxopt='-std=c++23' --host_cxxopt='-std=c++23'

build:unix --@capnp-cpp//src/kj:libdl=True

# Bazel uses CC to compile C and C++ actions, no need to define CXX.

build:unix --repo_env=BAZEL_COMPILER=clang

build:unix --repo_env=CC=clang

build:unix --test_env=LLVM_SYMBOLIZER=llvm-symbolizer

# Warning options.

build:unix --cxxopt='-Wall' --host_cxxopt='-Wall'

build:unix --cxxopt='-Wextra' --host_cxxopt='-Wextra'

build:unix --cxxopt='-Wunused-function' --host_cxxopt='-Wunused-function'

build:unix --cxxopt='-Wunused-lambda-capture' --host_cxxopt='-Wunused-lambda-capture'

build:unix --cxxopt='-Wunused-variable' --host_cxxopt='-Wunused-variable'

build:unix --cxxopt='-Wno-sign-compare' --host_cxxopt='-Wno-sign-compare'

build:unix --cxxopt='-Wno-unused-parameter' --host_cxxopt='-Wno-unused-parameter'

build:unix --cxxopt='-Wno-missing-field-initializers' --host_cxxopt='-Wno-missing-field-initializers'

build:unix --cxxopt='-Wsuggest-override'

build:linux --config=unix

build:macos --config=unix

# Disable the deprecated rules_cc macOS toolchain – no need to configure this since we always use

# the apple_support one, this will be removed in the future. See https://github.com/bazelbuild/rules_cc/issues/754

# for context.

build:macos --repo_env=BAZEL_USE_LEGACY_MACOS_TOOLCHAIN=0

# Support macOS 13 as the minimum version. There should be at least a warning when backward

# compatibility is broken as -Wunguarded-availability-new is enabled by default.

build:macos --macos_minimum_os=13.5

build:macos --host_macos_minimum_os=13.5

# Avoid emitting duplicate unwind info where compact unwind info can be used. This reduces the

# object size by ~5% on average, improving disk space usage and link times. The final binary size

# is not affected. Note that this is on-by-default on arm64, but turning it on for all mac builds

# is easier than adding the flag only on x86. See https://reviews.llvm.org/D122258 for detailed

# information on the flag.

build:macos --copt='-femit-dwarf-unwind=no-compact-unwind'

# Cross-Compilation

# Only cross-compiling on macOS from Apple Silicon to x86_64 is supported – using apple_support

# makes this much easier than on other platforms. We could define a configuration for cross-

# compiling from Intel Mac too, but it lacks a means to run Apple Silicon binaries. We would have to

# change V8 mksnapshot to build in the host configuration again (effectively compiling much of V8

# twice) and couldn't run tests, so it would provide little value.

#

# Define the target platform

build:macos-cross-x86_64 --cpu=darwin_x86_64 --host_cpu=darwin_arm64 --platforms //:macOS_x86

# Some cross-compiled tests are slower when run over Rosetta, increase the medium test size timeout.

# Test performance is still very much satisfactory considering that emulation is being used here.

build:macos-cross-x86_64 --test_timeout=1,30,60,240

# On Linux, always link libc++ statically to avoid compatibility issues with different OS versions.

# macOS links with dynamic libc++ by default, which has good backwards compatibility.

# Drop default link flags, which include libstdc++ for Linux

build:linux --features=-default_link_libs --host_features=-default_link_libs

build:linux --cxxopt='-stdlib=libc++' --host_cxxopt='-stdlib=libc++'

build:linux --linkopt='-stdlib=libc++' --host_linkopt='-stdlib=libc++'

build:linux --linkopt='-l:libc++.a' --linkopt='-lm' --linkopt='-static-libgcc'

# We don't expect to distribute host tools, no need to statically link libgcc.

# TODO(cleanup): Ideally we'd also use shared libc++ here, we'd just need to install the

# libunwind-<version>-dev and libc++abi-<version>-dev packages on CI to have all of shared libc++

# available.

build:linux --host_linkopt='-l:libc++.a' --host_linkopt='-lm'

# On Linux, enable PIC. In macos pic is the default, and the objc_library rule does not work

# correctly if we use this flag since it will not find the object files to include

# https://github.com/bazelbuild/bazel/issues/12439#issuecomment-914449079

build:linux --force_pic

# On Linux, garbage collection sections and optimize binary size. These do not apply to the macOS

# toolchain.

build:linux --linkopt="-Wl,--gc-sections"

build:linux --copt="-ffunction-sections" --host_copt="-ffunction-sections"

build:linux --copt="-fdata-sections" --host_copt="-fdata-sections"

# On Linux, use clang lld.

build:linux --linkopt="-fuse-ld=lld"

# Improve link performance by limiting the link stage to 8 threads – LLD link times see little if

# any improvement beyond 8 threads (see https://reviews.llvm.org/D147493).

build:linux --linkopt="-Wl,--threads=8"

#

# Windows

#

# See https://bazel.build/configure/windows#symlink

startup --windows_enable_symlinks

build:windows --workspace_status_command=./tools/windows/workspace-status.cmd

build:windows --enable_runfiles

# We use LLVM's MSVC-compatible compiler driver to compile our code on Windows,

# as opposed to using MSVC directly. This enables us to use the "same" compiler

# frontend on Linux, macOS, and Windows, massively reducing the effort required

# to compile workerd on Windows. Notably, this provides proper support for

# `#pragma once` when using symlinked virtual includes, `__atomic_*` functions,

# a standards-compliant preprocessor, support for GNU statement expressions

# used by some KJ macros, and understands the `.c++` extension by default.

# As of bazel 7, toolchain resolution is enabled by default, so we need to define a platform for

# the clang-cl build.

build:windows --extra_toolchains=@local_config_cc//:cc-toolchain-x64_windows-clang-cl

build:windows --extra_execution_platforms=//:x64_windows-clang-cl

# The Windows fastbuild bazel configuration is broken in that it necessarily generates PDB debug

# information while the Linux and macOS toolchains only compile with debug information in the dbg

# configuration or when requested with the -g flag. This causes huge increases in compile time and

# disk/cache space usage – a single test may come with a 490MB PDB file.

# In an optional configuration, use the opt configuration and manually disable optimizations as a

# workaround.

build:windows_no_dbg -c opt

build:windows_no_dbg --copt='/Od'

build:windows_no_dbg --linkopt='/INCREMENTAL:NO'

build:windows_no_dbg --features=-smaller_binary

# Mitigate the large size impact of Windows debug binaries somewhat by applying string merging and

# linker garbage collection.

build:windows_dbg --config=debug

build:windows_dbg --copt='/Gy' --copt='/Gw'

build:windows_dbg --linkopt='/OPT:REF'

build:windows_dbg --linkopt='/OPT:LLDTAILMERGE' --linkopt='/OPT:SAFEICF'

# This hides inline symbols in classes that are marked to be exported, similar to

# -fvisibility-inlines-hidden on Unix systems (https://blog.llvm.org/2018/11/30-faster-windows-builds-with-clang-cl_14.html)

# Currently this only reduces object sizes slightly, larger gains are possible if we compile V8 as

# a shared library.

build:windows --copt='/Zc:dllexportInlines-'

# Configuration for header parsing. Requires bazel toolchain support (available for macOS, Linux).

build:parse_headers --features=parse_headers --process_headers_in_dependencies

# Silence some capnproto warnings/errors that are not relevant for header parsing

build:parse_headers --per_file_copt='.*\.h@-Wno-unused-function,-Wno-pragma-system-header-outside-header'

build:parse_headers --per_file_copt=external/+http+capnp-cpp/src/kj/common.h@-Wno-unreachable-code

build:parse_headers --per_file_copt=external/+http+capnp-cpp/src/capnp/arena.h@-DCAPNP_PRIVATE

# optimized configuration

build:opt -c opt

build:opt --@capnp-cpp//src/kj:debug_memory=False

# Release configuration.

build:release --config=opt

build:release --@rules_rust//:extra_rustc_flag=-Ccodegen-units=1

# enable -O3 for the release configuration. Based on benchmarking there is little difference in

# performance, but -O3 should generally be expected to be faster for at least parts of the workerd API.

build:release_unix --copt='-O3'

build:release_unix --config=release

build:release_linux --config=release_unix

build:release_linux --linkopt="-Wl,-O2"

build:release_macos --config=release_unix

# Disable generating LC_DATA_IN_CODE and LC_FUNCTION_STARTS binary sections, two rarely used types

# of macOS debug info. These sections are largely undocumented, but are used by LLDB to improve

# debugging on binaries that are otherwise stripped. There should be no need to include this

# data in releases.

build:release_macos --linkopt="-Wl,-no_data_in_code_info"

build:release_macos --linkopt="-Wl,-no_function_starts"

# Cross-compiled release build for x86_64.

build:release_macos_cross_x86_64 --config=release_macos

build:release_macos_cross_x86_64 --config=macos-cross-x86_64

# On macOS, optionally compile using LLD (19 or higher is compatible with the default flags added by

# apple_support). Requires Homebrew's lld package to be installed and symlinked into /usr/local/bin.

# This is less CPU intensive than the system linker, but also slightly slower in terms of wall time

# since it is less parallel. More importantly, it allows us to enable LLD's ICF pass, which

# significantly decreases binary sizes. We could use Xcode 16's -Wl,-deduplicate option instead, but

# LLD's ICF appears to be superior. We also want to enable ICF for Linux, but there it causes

# warnings when dynamically linking with libc++.

build:macos_lld --linkopt=-fuse-ld=lld --linkopt=--ld-path=/usr/local/bin/ld64.lld

build:macos_lld_icf --config=macos_lld

build:macos_lld_icf --linkopt="-Wl,--icf=safe"

build:release_windows --config=release

# Windows uses /O2 as its preferred optimization setting and enabled by bazel in the opt

# configuration, but for clang-cl this is equivalent to only -O2 and a few other things. -O3 is

# not exposed directly in the clang-cl driver, but we can access regular clang

# flags using the /clang prefix anyway. https://clang.llvm.org/docs/UsersManual.html#the-clang-option

build:release_windows --copt="/clang:-O3"

# clang-cl does not enable strict aliasing by default to match MSVC's approach, unlike clang on

# Unix which turns it on for opt builds.

build:release_windows --copt="-fstrict-aliasing"

# TODO(soon): Investigate these issues on an actual Windows system.

# Compiling these files causes clang-cl 20 to crash on Windows release builds, work around this by

# disabling inlining (using /Od would work too but we still want to have whatever optimizations we

# can have)

build:release_windows --per_file_copt="src/workerd/server/server"@/clang:-fno-inline

build:release_windows --per_file_copt="src/workerd/server/container-client"@/clang:-fno-inline

# Work around Windows test failures in rpc-related tests

build:release_windows --per_file_copt=src/workerd/io/worker-interface@/clang:-fno-inline

build:windows --cxxopt='/std:c++23preview' --host_cxxopt='/std:c++23preview'

build:windows --copt='/D_CRT_USE_BUILTIN_OFFSETOF' --host_copt='/D_CRT_USE_BUILTIN_OFFSETOF'

build:windows --copt='/DWIN32_LEAN_AND_MEAN' --host_copt='/DWIN32_LEAN_AND_MEAN'

build:windows --copt='/EHs' --host_copt='/EHs'

# The `/std:c++23preview` argument is unused during BoringSSL compilation and we don't

# want a warning when compiling each file.

build:windows --per_file_copt=external/boringssl@-Wno-unused-command-line-argument --host_per_file_copt=external/boringssl@-Wno-unused-command-line-argument

# MSVC disappointingly sets __cplusplus to 199711L by default. Defining /Zc:__cplusplus makes it

# set the correct value. We currently don't check __cplusplus, but some dependencies do.

build:windows --cxxopt='/Zc:__cplusplus' --host_cxxopt='/Zc:__cplusplus'

# Coverage configuration using LLVM tools. These environment variables are used by rules_cc

# to locate LLVM coverage tools. Users should ensure llvm-profdata and llvm-cov are available

# in PATH (create symlinks to version-specific binaries if needed, e.g., ln -s llvm-cov-19 llvm-cov).

build:coverage --repo_env=BAZEL_USE_LLVM_NATIVE_COVERAGE=1

# GCOV is used by rules_cc to merge raw profile data (.profraw) into indexed profile data (.profdata)

build:coverage --repo_env=GCOV=llvm-profdata

# COVERAGE_GCOV_PATH is used by collect_cc_coverage.sh for merging .profraw files.

build:coverage --repo_env=COVERAGE_GCOV_PATH=/usr/bin/llvm-profdata

# BAZEL_LLVM_COV is used by collect_cc_coverage.sh to generate LCOV reports from profile data

build:coverage --repo_env=BAZEL_LLVM_COV=llvm-cov

build:coverage --experimental_use_llvm_covmap

# experimental_generate_llvm_lcov tells collect_cc_coverage to use llvm-cov export to generate LCOV

# format instead of just outputting raw profdata. LLVM_COV specifies the llvm-cov binary to use.

build:coverage --experimental_generate_llvm_lcov

# Ensure that we fetch coverage data from remote cache

build:coverage --experimental_fetch_all_coverage_outputs

build:coverage --experimental_split_coverage_postprocessing

# Allow coverage outputs to be writable for post-processing

build:coverage --experimental_writable_outputs

build:coverage --collect_code_coverage

# Only instrument source code, not tests or tools - significantly speeds up coverage builds

build:coverage --instrumentation_filter="^//src/workerd[/:],^//src/rust[/:]"

build:coverage --instrument_test_targets

# Disable coverage instrumentation for external dependencies to speed up compilation.

# Coverage for V8/external code is not useful for our purposes.

# These flags negate -fprofile-instr-generate and -fcoverage-mapping set by rules_cc.

build:coverage --per_file_copt=external/.*@-fno-profile-instr-generate,-fno-coverage-mapping

# KJ uses _exit() by default which bypasses atexit handlers and prevents LLVM profile runtime

# from writing coverage data. KJ_CLEAN_SHUTDOWN forces use of normal exit() instead.

build:coverage --test_env=KJ_CLEAN_SHUTDOWN=1

# Use -O1 for faster compilation - coverage builds don't need heavy optimization

build:coverage --copt=-O1

# Reduce debug info for faster compilation and smaller binaries

build:coverage --copt=-g1

# Use limited coverage mode for smaller binaries and faster execution (used by Chromium)

build:coverage --copt=-mllvm --copt=-limited-coverage-experimental=true

coverage --test_tag_filters=-off-by-default,-requires-fuzzilli,-requires-container-engine,-lint,-benchmark,-workerd-benchmark,-no-coverage

# Coverage instrumentation slows down test execution, so extend timeouts

# We disable enormous tests due to the slowdown (CI jobs have a 6h max duration)

coverage --test_size_filters=-enormous

coverage --test_timeout=240,240,240,240

coverage --build_tests_only

# This config is defined internally and enabled on many machines.

# Defining it as empty just so these machines can run build commands from the workerd repo

build:rosetta-arm64 --define=rosetta_arm64_no_op=1