build/moz.configure/flags.configure
author AndiAJ <andiaj@users.noreply.github.com>
Tue, 15 Jul 2025 12:24:39 +0000 (10 hours ago)
changeset 796640 bb851a378010881961ccfae598f355ea1211941d
parent 783824 bd9712a5d806edb84c4c7b291df36ede0e1e6e68
permissions -rw-r--r--
Bug 1977313 - Fix failing custom search engines related UI tests r=aaronmt The UI test started to fail after this [[ https://phabricator.services.mozilla.com/D252233 | change ]] landed. To fix the 2 UI tests I've removed the snackbar assertions. Both tests successfuly passed 10x on Firebase ✅ Differential Revision: https://phabricator.services.mozilla.com/D257244
# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
# vim: set filetype=python:
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# The following flags are explicitly passed to C++ compiler invocations from rust
# even when only passing base flags. If you add more similarly important flags,
# please consider whether they should be handled the same way.
# See config/makefiles/rust.mk.
# We support C++14, but we don't want to enable the sized deallocation
# facilities in C++14 yet.
check_and_add_flag("-fno-sized-deallocation", compiler=cxx_compiler)
# Likewise for C++17 and aligned allocation.  It's not immediately obvious
# from the clang and GCC documentation, but they both support this.
check_and_add_flag("-fno-aligned-new", compiler=cxx_compiler)


# Detect static linkage of libstdc++
# ==============================================================
@depends(
    cxx_compiler,
    extra_toolchain_flags,
    linker_ldflags,
    llvm_objdump,
    when=target_has_linux_kernel,
)
@checking("whether we're trying to statically link with libstdc++")
@imports("os")
@imports("re")
@imports(_from="mozbuild.shellutil", _import="split", _as="shell_split")
def link_libstdcxx_statically(
    cxx_compiler,
    extra_toolchain_flags,
    linker_ldflags,
    llvm_objdump,
):
    with create_temporary_file(suffix=".out") as bin_path:
        # This test is quite conservative: it assumes dynamic linkage if the
        # compilation step fails or if the binary format is not supported. But
        # it still detects basic issues.

        # FIXME: At some point we should make these dependencies explicit.
        # See #1903233.
        env_flags = []
        if "CXXFLAGS" in os.environ:
            env_flags.extend(shell_split(os.environ["CXXFLAGS"]))
        if "LDFLAGS" in os.environ:
            env_flags.extend(shell_split(os.environ["LDFLAGS"]))

        if (
            try_invoke_compiler(
                None,
                [cxx_compiler.compiler]
                + env_flags
                + cxx_compiler.flags
                + linker_ldflags,
                cxx_compiler.language,
                """
                    #include <iostream>
                    int main() { std::cout << 1;}
                """,
                ["-o", bin_path] + (extra_toolchain_flags or []),
                wrapper=cxx_compiler.wrapper,
                onerror=lambda: None,
            )
            is not None
        ):
            objdump_command = [llvm_objdump, "--private-headers", bin_path]
            result, stdout, stderr = get_cmd_output(*objdump_command)
            # This is very conservative :-).
            return (
                result == 0
                and not stderr
                and not re.search("NEEDED.*lib(std)?c\\+\\+", stdout)
            )


@depends(when=link_libstdcxx_statically)
def check_libstdcxx_linkage():
    die("Firefox does not support linking statically with libstdc++")


check_and_add_flag(
    "-mieee",
    when=target_has_linux_kernel & depends(target.cpu)(lambda cpu: cpu == "Alpha"),
)

# Identical Code Folding
option(
    "--enable-icf",
    help="{Enable|Disable} Identical Code Folding",
    default=~developer_options,
)
enable_icf = depends("--enable-icf")(lambda v: bool(v))


with only_when(building_with_gnu_compatible_cc):
    with only_when(~developer_options | enable_icf):
        add_flag("-ffunction-sections")
        add_flag("-fdata-sections")
    add_flag("-fno-math-errno")
    add_flag("-fno-exceptions", compiler=cxx_compiler)

add_flag("-D_HAS_EXCEPTIONS=0", when=target_is_windows)

# We only use -faddrsig with clang on android, and all version of clang we
# support have it.
add_addrsig_flag = depends(c_compiler, when=target_is_android)(
    lambda c: c.type == "clang"
)


@depends(
    c_compiler,
    extra_toolchain_flags,
    linker_ldflags,
    llvm_objdump,
    add_addrsig_flag,
    when=building_with_gnu_compatible_cc & gcc_use_gnu_ld & enable_icf,
)
@checking("whether the linker supports Identical Code Folding")
@imports("os")
def linker_supports_icf(
    c_compiler, extra_toolchain_flags, linker_ldflags, llvm_objdump, add_addrsig_flag
):
    with create_temporary_file(suffix=".out") as bin_path:
        if (
            try_invoke_compiler(
                None,
                [c_compiler.compiler] + c_compiler.flags + linker_ldflags,
                c_compiler.language,
                """
                                 int foo() {return 42;}
                                 int bar() {return 42;}
                                 int main() {return 0;}
                                 """,
                ["-o", bin_path, "-Wl,--icf=safe", "-ffunction-sections"]
                + (["-faddrsig"] if add_addrsig_flag else [])
                + (extra_toolchain_flags or []),
                wrapper=c_compiler.wrapper,
                onerror=lambda: None,
            )
            is not None
        ):
            objdump_command = [llvm_objdump, "-t", bin_path]
            result = check_cmd_output(*objdump_command, onerror=lambda: None)
            if result is not None:
                sym_addr = {
                    line[5]: line[0]
                    for line in [line.split() for line in result.splitlines()]
                    if len(line) >= 6
                }
                foo_addr = sym_addr.get("foo")
                bar_addr = sym_addr.get("bar")
                return foo_addr == bar_addr and foo_addr is not None


@depends(compilation_flags, linker_flags, add_addrsig_flag, when=linker_supports_icf)
def add_icf_flags(compilation_flags, linker_flags, add_addrsig_flag):
    if add_addrsig_flag:
        compilation_flags.cflags.append("-faddrsig")
        compilation_flags.cxxflags.append("-faddrsig")
    linker_flags.ldflags.append("-Wl,--icf=safe")


option(
    "--disable-new-pass-manager",
    help="Use the legacy LLVM pass manager in clang builds",
)


@depends(
    "--enable-new-pass-manager",
    c_compiler,
    host,
    target,
    "MOZ_PGO",
    enable_fuzzing,
    ubsan,
)
def pass_manager(enabled, compiler, host, target, pgo, enable_fuzzing, ubsan):
    if compiler.type not in ("clang", "clang-cl"):
        return None

    # As of clang 13, the default pass manager is the new one.
    if compiler.version >= "13.0.0":
        if enabled:
            return namespace(flags=None, enabled=True)
        if compiler.type == "clang":
            return namespace(flags=["-flegacy-pass-manager"], enabled=False)
        if compiler.type == "clang-cl":
            return namespace(flags=["-Xclang", "-flegacy-pass-manager"], enabled=False)

    if not enabled:
        if compiler.version >= "15.0.0":
            die("--disable-new-pass-manager is only supported with clang < 15")
        return None
    if compiler.version < "9.0.0":
        if enabled.origin != "default":
            die("--enable-new-pass-manager is only supported with clang >= 9")
        return None

    if host.os == "OSX":
        # Some native Mac builds hang with the new pass manager. Given the
        # inability to test in CI, don't take the risk of further breakage.
        if enabled.origin != "default":
            die(
                "--enable-new-pass-manager causes problems on mac hosts with clang < 13"
            )
        return None
    if target.os == "OSX" and not pgo:
        # Also disable when cross-compiling to Mac, because plain-ish opt
        # builds hang. Variants like asan and ccov work fine, but it would be
        # too tedious to test them all here. PGO is the only thing that matters
        # enough to make an exception for.
        if enabled.origin != "default":
            die(
                "--enable-new-pass-manager causes problems on mac builds with clang < 13"
            )
        return None
    if enable_fuzzing and compiler.version < "10.0.0":
        # Clang 9 does not seem to play well with libFuzzer
        if enabled.origin != "default":
            die(
                "--enable-new-pass-manager causes problems on fuzzing builds with clang < 10"
            )
        return None
    if ubsan and compiler.version == "10.0.0":
        # Clang 10.0.0 hangs with some ubsan-inserted code constructs.
        # This was fixed in 10.0.1 (https://llvm.org/pr45835)
        if enabled.origin != "default":
            die(
                "--enable-new-pass-manager causes problems with ubsan builds with clang 10.0.0"
            )
        return None
    if compiler.type == "clang":
        return namespace(flags=["-fexperimental-new-pass-manager"], enabled=True)
    elif compiler.type == "clang-cl":
        return namespace(
            flags=["-Xclang", "-fexperimental-new-pass-manager"], enabled=True
        )


set_config("MOZ_PASS_MANAGER_FLAGS", pass_manager.flags)

# Debugging options
##


@depends(moz_debug, asan, target, "--enable-jemalloc")
def moz_no_debug_rtl(moz_debug, asan, target, enable_jemalloc):
    if not moz_debug or asan:
        return True
    if enable_jemalloc and target.kernel == "WINNT":
        return True


set_config("MOZ_NO_DEBUG_RTL", moz_no_debug_rtl)


@depends(
    try_compile(
        includes=["stdio.h"],
        body='puts("Hello World");',
        check_msg="for valid debug flags",
        flags=debug_flags,
        when=moz_debug,
    ),
    debug_flags,
    when=moz_debug,
)
@imports(_from="mozbuild.shellutil", _import="quote")
def check_debug_flags(check, flags):
    if not check:
        die(f"These compiler flags are invalid: {quote(*flags)}")


# Try to make builds more reproducible and allow sharing built artifacts across
# source and object directories by using -ffile-prefix-map and friends.  To
# "unwind" the prefix maps, use:
#
# (gdb) set substitute-path /topsrcdir/ $topsrcdir/
#
# (lldb) settings set target.source-map /topobjdir/ $topobjdir/
#
# See, for example, https://lldb.llvm.org/use/map.html.
@depends(
    path_remapping,
    path_remappings,
    c_compiler,
)
@imports(_from="os", _import="sep")
def file_prefix_map_flags(path_remapping, path_remappings, compiler):
    if "c" not in path_remapping:
        return []

    if (compiler.type == "gcc" and compiler.version < "8.1") or (
        compiler.type in ("clang", "clang-cl") and compiler.version < "10.0.0"
    ):
        die(
            f"Compiler of type {compiler.type} and version {compiler.version} "
            "does not support --enable-path-remapping."
        )

    flags = []
    for old, new in path_remappings:
        # We would prefer to use just -ffile-prefix-map, but clang-cl doesn't
        # seem to recognize it.
        for flag in ("-fdebug-prefix-map", "-fmacro-prefix-map"):
            flag = f"{flag}={old}={new}"
            if compiler.type in ("gcc", "clang"):
                flags.append(flag)
            elif compiler.type == "clang-cl":
                flags.extend(["-Xclang", flag])

    return flags


set_config("MOZ_FILE_PREFIX_MAP_FLAGS", file_prefix_map_flags)


@depends(developer_options, when=building_with_gnu_compatible_cc)
def check_build_id_uuid(developer_options):
    return developer_options


@depends(developer_options, when=building_with_gnu_compatible_cc)
def check_build_id_sha1(developer_options):
    return not developer_options


check_and_add_flag("-pipe", when=building_with_gcc)

check_and_add_linker_flag("-Wl,--build-id=uuid", when=check_build_id_uuid)
check_and_add_linker_flag("-Wl,--build-id=sha1", when=check_build_id_sha1)

check_and_add_asm_flag("-Wa,--noexecstack", when=building_with_gnu_compatible_cc)
check_and_add_linker_flag("-Wl,-z,noexecstack", when=building_with_gnu_compatible_cc)
check_and_add_linker_flag("-Wl,-z,text", when=building_with_gnu_compatible_cc)
check_and_add_linker_flag("-Wl,-z,relro", when=building_with_gnu_compatible_cc)
check_and_add_linker_flag("-Wl,-z,now", when=building_with_gnu_compatible_cc)
check_and_add_linker_flag("-Wl,-z,nocopyreloc", when=building_with_gnu_compatible_cc)

check_and_add_linker_optimize_flag("-Wl,-dead_strip", when=target_is_darwin & ~dtrace)

check_and_add_asm_flag(
    "-fPIC", when=building_with_gnu_compatible_cc & ~target_is_windows
)
check_and_add_flag("-fPIC", when=building_with_gnu_compatible_cc & ~target_is_windows)
set_define("PIC", True, when=target_is_netbsd)

# DSO flags manipulations
have_linker_support_ignore_unresolved = try_link(
    flags=["-Wl,--ignore-unresolved-symbol,environ"],
    check_msg="for --ignore-unresolved-symbol option to the linker",
    when=building_with_gnu_compatible_cc
    & gcc_use_gnu_ld
    & depends(target)(lambda t: t.os in ("DragonFly", "FreeBSD", "NetBSD", "OpenBSD")),
)


@depends(
    dso_flags,
    gcc_use_gnu_ld,
    target,
    asan | msan | any_ubsan | tsan | enable_fuzzing_interfaces,
    have_linker_support_ignore_unresolved,
    when=building_with_gnu_compatible_cc,
)
@imports(_from="os", _import="environ")
def add_gnu_specific_dso_flags(
    dso_flags,
    use_gnu_ld,
    target,
    use_sanitizer_runtime,
    have_linker_support_ignore_unresolved,
):
    ldopts = []
    if target.kernel != "Darwin":
        ldopts.append("-shared")

    if use_gnu_ld:
        # Some tools like ASan use a runtime library that is only
        # linked against executables, so we must allow undefined
        # symbols for shared objects in some cases.
        if not use_sanitizer_runtime:
            if target.os != "WINNT":
                # Don't allow undefined symbols in libraries
                ldopts.append("-Wl,-z,defs")

            # BSDs need `environ' exposed for posix_spawn (bug 753046)
            if target.os in ("DragonFly", "FreeBSD", "NetBSD", "OpenBSD"):
                if have_linker_support_ignore_unresolved:
                    ldopts.append("-Wl,--ignore-unresolved-symbol,environ")
                else:
                    ldopts.append("-Wl,--warn-unresolved-symbols")

                if librunpath := environ.get("LIBRUNPATH"):
                    if target.os == "NetBSD":
                        ldopts.insert(0, f"-Wl,-R{librunpath}")
                    elif target.os == "OpenBSD":
                        ldopts.insert(0, f"-R{librunpath}")

    dso_flags.ldopts.extend(ldopts)


@depends(dso_flags, target, when=~building_with_gnu_compatible_cc)
def add_non_gnu_dso_flags(dso_flags, target):
    ldopts = ["-SUBSYSTEM:WINDOWS,{}".format(win32_subsystem_version())]
    if target.cpu == "x86":
        ldopts.append("-MACHINE:X86")
    if target.cpu == "x86_64":
        ldopts.append("-MACHINE:X64")
    if target.cpu == "aarch64":
        ldopts.append("-MACHINE:ARM64")

    dso_flags.ldopts.extend(ldopts)


@depends(libfuzzer_flags, when=enable_fuzzing)
def sancov(libfuzzer_flags):
    for flag in libfuzzer_flags.use_flags:
        if "-fsanitize-coverage" in flag or "-fsanitize=fuzzer" in flag:
            return True
    return False


@depends(target, build_environment)
@imports(_from="os", _import="environ")
def moz_fix_link_paths(target, build_env):
    dist = build_env.dist
    flags = [f"-Wl,-rpath-link,{dist}/bin"]
    if target.kernel == "Darwin":
        return []
    if target.kernel == "WINNT":
        return []
    if target.kernel == "SunOS":
        return [f"-L{dist}/bin"]
    if target.os == "WASI":
        return []

    return flags


set_config("MOZ_FIX_LINK_PATHS", moz_fix_link_paths)


@depends("--enable-address-sanitizer", building_with_gnu_compatible_cc)
def check_Bsymbolic(enable_asan, building_with_gnu_compatible_cc):
    return enable_asan and building_with_gnu_compatible_cc


# ASan assumes no symbols are being interposed, and when that happens,
# it's not happy with it. Inconveniently, since Firefox is exporting
# libffi symbols and Gtk+3 pulls system libffi via libwayland-client,
# system libffi interposes libffi symbols that ASan assumes are in
# libxul, so it barfs about buffer overflows.
# Using -Wl,-Bsymbolic ensures no exported symbol can be interposed.
check_and_add_linker_flag("-Wl,-Bsymbolic", when=check_Bsymbolic)


# Check what kind of list files are supported by the linker
@depends(c_compiler, link, linker_ldflags, extra_toolchain_flags)
@checking("what kind of list files are supported by the linker")
@imports("os")
@imports(_from="__builtin__", _import="open")
def expand_libs_list_style(c_compiler, link, linker_flags, extra_flags):
    with create_temporary_file(suffix=".o") as objname, create_temporary_file(
        suffix=".list"
    ) as listname, create_temporary_file(suffix=".out") as outname:
        with open(listname, "w") as fd:
            fd.write(objname)

        cflags = c_compiler.flags

        if (
            try_invoke_compiler(
                # No configure_cache because it would not create the
                # expected output file.
                None,
                [c_compiler.compiler] + cflags,
                c_compiler.language,
                "int main() {}",
                ["-c", "-o", objname],
                wrapper=c_compiler.wrapper,
                onerror=lambda: None,
            )
            is None
        ):
            die("couldn't compile a simple C file")

        ldflags = linker_flags + (extra_flags or [])

        if c_compiler.type == "clang-cl":
            base_linker_cmd = [link] + ldflags + [f"-OUT:{outname}"]
        else:
            base_linker_cmd = [c_compiler.compiler] + cflags + ldflags + ["-o", outname]

        # -filelist is for the OS X linker.  We need to try -filelist
        # first because clang understands @file, but may pass an
        # oversized argument list to the linker depending on the
        # contents of @file.
        options = [
            ("linkerlist", f"-Wl,@{listname}"),
            ("filelist", f"-Wl,@{listname}"),
            ("list", f"@{listname}"),
        ]
        for kind, option in options:
            linker_cmd = base_linker_cmd + [option]
            if check_cmd_output(*linker_cmd, onerror=lambda: None) is not None:
                return kind
        die("Couldn't find one that works")


set_config("EXPAND_LIBS_LIST_STYLE", expand_libs_list_style)


# MOZ_PROGRAM_LDFLAGS
# ---------------------------------
@depends(building_with_gnu_compatible_cc, target)
def moz_program_ldflags(building_with_gnu_compatible_cc, target):
    if building_with_gnu_compatible_cc and target.kernel not in ("Darwin", "WASI"):
        return ["-pie"]


set_config("MOZ_PROGRAM_LDFLAGS", moz_program_ldflags)


@depends(host, when=depends(c_compiler)(lambda c: c.type == "clang-cl"))
def moz_debug_ldflags(host):
    flags = ["-DEBUG"]
    if host.kernel != "WINNT":
        # %_PDB% is a special signal to emit only the PDB basename. This
        # avoids problems in Windows tools that don't like forward-slashes.
        flags.append("-PDBALTPATH:%_PDB%")
    return flags


set_config("MOZ_DEBUG_LDFLAGS", moz_debug_ldflags)


# Objective-C/ Objective-C++ flags.
# ---------------------------------
@depends(compilation_flags, toolkit)
def add_cmflags(compilation_flags, toolkit):
    cmflags = ["-x", "objective-c", "-fobjc-exceptions"]
    cmmflags = ["-x", "objective-c++", "-fobjc-exceptions"]

    compilation_flags.cmflags.extend(cmflags)
    compilation_flags.cmmflags.extend(cmmflags)
    if toolkit == "uikit":
        uiflags = ["-fobjc-abi-version=2", "-fobjc-legacy-dispatch"]
        compilation_flags.cmflags.extend(uiflags)
        compilation_flags.cmmflags.extend(uiflags)


set_config("OS_COMPILE_CMFLAGS", compilation_flags.cmflags)
set_config("OS_COMPILE_CMMFLAGS", compilation_flags.cmmflags)


# Final flags settings
# ---------------------------------
@depends(host_c_compiler)
def host_optimize_flags(compiler):
    if compiler.type == "clang-cl":
        return ["-O2"]
    else:
        return ["-O3"]


set_config("HOST_OPTIMIZE_FLAGS", host_optimize_flags)


@depends("HOST_CPPFLAGS", host, host_c_compiler)
@imports(_from="mozbuild.shellutil", _import="split")
def host_cppflags(base_cppflags, host, compiler):
    flags = []
    if host.kernel == "WINNT":
        if compiler.type != "clang-cl":
            flags += ["-mwindows"]
        flags += ["-DXP_WIN", "-DWIN32", "-D_WIN32", "-D_CRT_SECURE_NO_WARNINGS"]
        if host.cpu == "x86_64":
            flags += ["-D_AMD64_"]
    elif host.kernel == "Darwin":
        flags += ["-DXP_UNIX", "-DXP_MACOSX"]
    else:
        flags += ["-DXP_UNIX"]
    if base_cppflags:
        flags += split(base_cppflags[0])
    return flags


@depends("HOST_CFLAGS", compilation_flags)
@imports(_from="mozbuild.shellutil", _import="split")
def host_cflags(base_cflags, compilation_flags):
    flags = list(compilation_flags.host_cflags)
    if base_cflags:
        flags += split(base_cflags[0])
    return flags


@depends("HOST_CXXFLAGS", compilation_flags)
@imports(_from="mozbuild.shellutil", _import="split")
def host_cxxflags(base_cxxflags, compilation_flags):
    flags = list(compilation_flags.host_cxxflags)
    if base_cxxflags:
        flags += split(base_cxxflags[0])
    return flags


@depends("HOST_LDFLAGS", linker_flags, host_linker_ldflags, host, host_c_compiler)
@imports(_from="mozbuild.shellutil", _import="split")
def host_ldflags(env_ldflags, linker_flags, host_linker_ldflags, host, compiler):
    flags = []
    if env_ldflags:
        flags += split(env_ldflags[0])
    flags += host_linker_ldflags
    if host.kernel == "WINNT" and compiler.type == "clang-cl":
        if host.cpu == "x86":
            flags += ["-MACHINE:X86"]
        elif host.cpu == "x86_64":
            flags += ["-MACHINE:X64"]
    flags += linker_flags.host_ldflags
    return flags


@depends("CPPFLAGS")
@imports(_from="mozbuild.shellutil", _import="split")
def os_cppflags(env_cppflags):
    flags = []
    if env_cppflags:
        flags = split(env_cppflags[0])
    return flags


@depends("CFLAGS", compilation_flags, android_flags, all_arm_flags)
@imports(_from="mozbuild.shellutil", _import="split")
def os_cflags(env_cflags, compilation_flags, android_flags, all_arm_flags):
    flags = []
    if android_flags:
        flags.extend(android_flags.cflags)
    if all_arm_flags:
        flags.extend(all_arm_flags)
    flags.extend(compilation_flags.cflags)
    if env_cflags:
        flags.extend(split(env_cflags[0]))
    return flags


@depends("CXXFLAGS", compilation_flags, android_flags, all_arm_flags)
@imports(_from="mozbuild.shellutil", _import="split")
def os_cxxflags(env_cxxflags, compilation_flags, android_flags, all_arm_flags):
    flags = []
    if android_flags:
        flags.extend(android_flags.cxxflags)
    if all_arm_flags:
        flags.extend(all_arm_flags)
    flags.extend(compilation_flags.cxxflags)
    if env_cxxflags:
        flags.extend(split(env_cxxflags[0]))
    return flags


@depends(
    "ASFLAGS",
    asm_flags,
    android_flags,
    all_arm_flags,
    defines_cpp_flags,
    c_compiler,
    build_project,
)
@imports(_from="mozbuild.shellutil", _import="split")
def os_asflags(
    env_asflags,
    asm_flags,
    android_flags,
    all_arm_flags,
    defines_cpp_flags,
    c_compiler,
    build_project,
):
    flags = []
    if android_flags:
        flags.extend(android_flags.asflags)
        flags.append("-DANDROID")
    if all_arm_flags:
        flags.extend(all_arm_flags)
    flags.extend(asm_flags.asflags)
    if build_project != "js" and c_compiler.type != "clang-cl":
        flags.extend(defines_cpp_flags)
    if env_asflags:
        flags.extend(split(env_asflags[0]))
    return flags


# VS2012+ defaults to -arch:SSE2. We want to target nothing more recent, so set
# that explicitly here unless another target arch has already been set.
@template
def add_sse2_flag_if_needed(flags):
    @depends(
        flags,
        when=~building_with_gnu_compatible_cc
        & depends(target.cpu)(lambda cpu: cpu == "x86"),
    )
    def add_sse2_flag(flags):
        is_arch_flag = lambda flag: flag.lower().startswith(("-arch:", "/arch:"))
        if not any(is_arch_flag(flag) for flag in flags):
            flags.append("-arch:SSE2")


add_sse2_flag_if_needed(os_cflags)
add_sse2_flag_if_needed(os_cxxflags)


@depends(compilation_flags, when=depends(target.os)(lambda os: os == "WASI"))
def add_thread_model_single(compilation_flags):
    compilation_flags.cxxflags.extend(["-mthread-model", "single"])


# Please keep these last in this file.
set_config("HOST_CPPFLAGS", host_cppflags)
set_config("HOST_CFLAGS", host_cflags)
set_config("HOST_CXXFLAGS", host_cxxflags)
set_config("HOST_LDFLAGS", host_ldflags)
set_config("OS_CPPFLAGS", os_cppflags)
set_config("OS_CFLAGS", os_cflags)
set_config("OS_CXXFLAGS", os_cxxflags)
set_config("ASFLAGS", os_asflags)
set_config("DSO_LDOPTS", dso_flags.ldopts)
set_config("LIBS", depends("LIBS")(lambda x: x))