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Make windows toolchain configurable with BAZEL_*OPTS #431

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3b661c0
Make windows toolchain configurable with BAZEL_*OPTS
AustinSchuh Jul 5, 2025
731963a
Deduplicate the default field value for BAZEL_WIN32_WINNT
AustinSchuh Jul 23, 2025
c460d54
Merge branch 'main' into configurable_windows_toolchain
AustinSchuh Jul 23, 2025
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50 changes: 50 additions & 0 deletions cc/private/toolchain/BUILD.windows.tpl
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -124,6 +124,11 @@ cc_toolchain_config(
cxx_builtin_include_directories = [%{cxx_builtin_include_directories}],
tool_paths = {%{tool_paths}},
tool_bin_path = "%{tool_bin_path}",
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -170,6 +175,11 @@ cc_toolchain_config(
tool_bin_path = "%{tool_bin_path}",
default_compile_flags = ["-m32"],
default_link_flags = ["-m32"],
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -214,6 +224,11 @@ cc_toolchain_config(
tool_bin_path = "%{mingw_tool_bin_path}",
cxx_builtin_include_directories = [%{mingw_cxx_builtin_include_directories}],
tool_paths = {%{mingw_tool_paths}},
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -260,6 +275,11 @@ cc_toolchain_config(
tool_paths = {%{mingw_tool_paths}},
default_compile_flags = ["-m32"],
default_link_flags = ["-m32"],
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -331,6 +351,11 @@ cc_toolchain_config(
fastbuild_mode_debug_flag = "%{fastbuild_mode_debug_flag_x64}",
supports_parse_showincludes = %{msvc_parse_showincludes_x64},
shorten_virtual_includes = True,
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -401,6 +426,11 @@ cc_toolchain_config(
fastbuild_mode_debug_flag = "%{fastbuild_mode_debug_flag_x86}",
supports_parse_showincludes = %{msvc_parse_showincludes_x86},
shorten_virtual_includes = True,
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -471,6 +501,11 @@ cc_toolchain_config(
fastbuild_mode_debug_flag = "%{fastbuild_mode_debug_flag_arm}",
supports_parse_showincludes = %{msvc_parse_showincludes_arm},
shorten_virtual_includes = True,
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -541,6 +576,11 @@ cc_toolchain_config(
fastbuild_mode_debug_flag = "%{fastbuild_mode_debug_flag_arm64}",
supports_parse_showincludes = %{msvc_parse_showincludes_arm64},
shorten_virtual_includes = True,
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -608,6 +648,11 @@ cc_toolchain_config(
dbg_mode_debug_flag = "%{clang_cl_dbg_mode_debug_flag_x64}",
fastbuild_mode_debug_flag = "%{clang_cl_fastbuild_mode_debug_flag_x64}",
supports_parse_showincludes = %{clang_cl_parse_showincludes_x64},
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down Expand Up @@ -676,6 +721,11 @@ cc_toolchain_config(
dbg_mode_debug_flag = "%{clang_cl_dbg_mode_debug_flag_arm64}",
fastbuild_mode_debug_flag = "%{clang_cl_fastbuild_mode_debug_flag_arm64}",
supports_parse_showincludes = %{clang_cl_parse_showincludes_arm64},
c_flags = [%{c_flags}],
conly_flags = [%{conly_flags}],
cxx_flags = [%{cxx_flags}],
link_flags = [%{link_flags}],
%{win32_winnt_flag}
)

toolchain(
Expand Down
1 change: 1 addition & 0 deletions cc/private/toolchain/cc_configure.bzl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -125,6 +125,7 @@ cc_autoconf = repository_rule(
"BAZEL_TARGET_SYSTEM",
"BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN",
"BAZEL_USE_LLVM_NATIVE_COVERAGE",
"BAZEL_WIN32_WINNT",
"BAZEL_LLVM",
"BAZEL_IGNORE_SYSTEM_HEADERS_VERSIONS",
"USE_CLANG_CL",
Expand Down
42 changes: 42 additions & 0 deletions cc/private/toolchain/windows_cc_configure.bzl
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,9 @@ load(
"auto_configure_warning_maybe",
"escape_string",
"execute",
"get_starlark_list",
"resolve_labels",
"split_escaped",
"write_builtin_include_directory_paths",
)

Expand Down Expand Up @@ -848,6 +850,45 @@ def _get_msvc_deps_scanner_vars(repository_ctx, paths, template_vars, target_arc
"%{msvc_deps_scanner_wrapper_path_" + target_arch + "}": "msvc_deps_scanner_wrapper_" + target_arch + ".bat",
}

def _get_copts(repository_ctx):
"""Get the variables we need to populate the msys/mingw toolchains."""
conly_opts = split_escaped(_get_env_var(
repository_ctx,
"BAZEL_CONLYOPTS",
"",
), ":")
c_opts = split_escaped(_get_env_var(
repository_ctx,
"BAZEL_COPTS",
"",
), ":")
cxx_opts = split_escaped(_get_env_var(
repository_ctx,
"BAZEL_CXXOPTS",
"",
), ":")
link_opts = split_escaped(_get_env_var(
repository_ctx,
"BAZEL_LINKOPTS",
"",
), ":")
win32_winnt_opts = _get_env_var(
repository_ctx,
"BAZEL_WIN32_WINNT",
None,
)
copts_vars = {
"%{c_flags}": get_starlark_list(c_opts),
"%{conly_flags}": get_starlark_list(conly_opts),
"%{cxx_flags}": get_starlark_list(cxx_opts),
"%{link_flags}": get_starlark_list(link_opts),
# None means the user didn't provide the override.
# Fall back to the default in that case.
"%{win32_winnt_flag}": ' win32_winnt_flag = "' + escape_string(win32_winnt_opts) + '", ' if win32_winnt_opts != None else "",
}

return copts_vars

def configure_windows_toolchain(repository_ctx):
"""Configure C++ toolchain on Windows.

Expand Down Expand Up @@ -882,6 +923,7 @@ def configure_windows_toolchain(repository_ctx):
template_vars.update(msvc_vars_x64)
template_vars.update(_get_clang_cl_vars(repository_ctx, paths, msvc_vars_x64, "x64"))
template_vars.update(_get_msys_mingw_vars(repository_ctx))
template_vars.update(_get_copts(repository_ctx))
template_vars.update(_get_msvc_vars(repository_ctx, paths, "x86", msvc_vars_x64))
template_vars.update(_get_msvc_vars(repository_ctx, paths, "arm", msvc_vars_x64))
msvc_vars_arm64 = _get_msvc_vars(repository_ctx, paths, "arm64", msvc_vars_x64)
Expand Down
108 changes: 93 additions & 15 deletions cc/private/toolchain/windows_cc_toolchain_config.bzl
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Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,12 @@ all_link_actions = [
ACTION_NAMES.cpp_link_nodeps_dynamic_library,
]

lto_index_actions = [
ACTION_NAMES.lto_index_for_executable,
ACTION_NAMES.lto_index_for_dynamic_library,
ACTION_NAMES.lto_index_for_nodeps_dynamic_library,
]

def _use_msvc_toolchain(ctx):
return ctx.attr.cpu in ["x64_windows", "arm64_windows"] and (ctx.attr.compiler == "msvc-cl" or ctx.attr.compiler == "clang-cl")

Expand Down Expand Up @@ -566,6 +572,30 @@ def _impl(ctx):
user_compile_flags_feature = feature(
name = "user_compile_flags",
flag_sets = [
flag_set(
actions = [ACTION_NAMES.c_compile],
flag_groups = ([
flag_group(
flags = ctx.attr.conly_flags,
),
] if ctx.attr.conly_flags else []),
),
flag_set(
actions = [
ACTION_NAMES.linkstamp_compile,
ACTION_NAMES.cpp_compile,
ACTION_NAMES.cpp_header_parsing,
ACTION_NAMES.cpp_module_compile,
ACTION_NAMES.cpp_module_codegen,
ACTION_NAMES.lto_backend,
ACTION_NAMES.clif_match,
],
flag_groups = ([
flag_group(
flags = ctx.attr.cxx_flags,
),
] if ctx.attr.cxx_flags else []),
),
flag_set(
actions = [
ACTION_NAMES.preprocess_assemble,
Expand All @@ -579,7 +609,11 @@ def _impl(ctx):
ACTION_NAMES.cpp20_module_compile,
ACTION_NAMES.cpp20_module_codegen,
],
flag_groups = [
flag_groups = ([
flag_group(
flags = ctx.attr.c_flags,
),
] if ctx.attr.c_flags else []) + [
flag_group(
flags = ["%{user_compile_flags}"],
iterate_over = "user_compile_flags",
Expand Down Expand Up @@ -715,6 +749,14 @@ def _impl(ctx):
user_link_flags_feature = feature(
name = "user_link_flags",
flag_sets = [
flag_set(
actions = all_link_actions + lto_index_actions,
flag_groups = ([
flag_group(
flags = ctx.attr.link_flags,
),
] if ctx.attr.link_flags else []),
),
flag_set(
actions = all_link_actions,
flag_groups = [
Expand Down Expand Up @@ -743,6 +785,21 @@ def _impl(ctx):
],
)

default_compile_flags_list = [
"/DNOMINMAX",
"/D_CRT_SECURE_NO_DEPRECATE",
"/D_CRT_SECURE_NO_WARNINGS",
"/bigobj",
"/Zm500",
"/EHsc",
"/wd4351",
"/wd4291",
"/wd4250",
"/wd4996",
]
if ctx.attr.win32_winnt_flag:
default_compile_flags_list.append(ctx.attr.win32_winnt_flag)

default_compile_flags_feature = feature(
name = "default_compile_flags",
enabled = True,
Expand All @@ -765,19 +822,7 @@ def _impl(ctx):
],
flag_groups = [
flag_group(
flags = [
"/DNOMINMAX",
"/D_WIN32_WINNT=0x0601",
"/D_CRT_SECURE_NO_DEPRECATE",
"/D_CRT_SECURE_NO_WARNINGS",
"/bigobj",
"/Zm500",
"/EHsc",
"/wd4351",
"/wd4291",
"/wd4250",
"/wd4996",
],
flags = default_compile_flags_list,
),
],
),
Expand Down Expand Up @@ -1539,6 +1584,30 @@ def _impl(ctx):
name = "user_compile_flags",
enabled = True,
flag_sets = [
flag_set(
actions = [ACTION_NAMES.c_compile],
flag_groups = ([
flag_group(
flags = ctx.attr.conly_flags,
),
] if ctx.attr.conly_flags else []),
),
flag_set(
actions = [
ACTION_NAMES.linkstamp_compile,
ACTION_NAMES.cpp_compile,
ACTION_NAMES.cpp_header_parsing,
ACTION_NAMES.cpp_module_compile,
ACTION_NAMES.cpp_module_codegen,
ACTION_NAMES.lto_backend,
ACTION_NAMES.clif_match,
],
flag_groups = ([
flag_group(
flags = ctx.attr.cxx_flags,
),
] if ctx.attr.cxx_flags else []),
),
flag_set(
actions = [
ACTION_NAMES.assemble,
Expand All @@ -1555,7 +1624,11 @@ def _impl(ctx):
ACTION_NAMES.lto_backend,
ACTION_NAMES.clif_match,
],
flag_groups = [
flag_groups = ([
flag_group(
flags = ctx.attr.c_flags,
),
] if ctx.attr.c_flags else []) + [
flag_group(
flags = ["%{user_compile_flags}"],
iterate_over = "user_compile_flags",
Expand Down Expand Up @@ -1663,14 +1736,18 @@ cc_toolchain_config = rule(
"abi_libc_version": attr.string(),
"abi_version": attr.string(),
"archiver_flags": attr.string_list(default = []),
"c_flags": attr.string_list(),
"compiler": attr.string(),
"conly_flags": attr.string_list(),
"cpu": attr.string(mandatory = True),
"cxx_builtin_include_directories": attr.string_list(),
"cxx_flags": attr.string_list(),
"dbg_mode_debug_flag": attr.string(default = ""),
"default_compile_flags": attr.string_list(default = []),
"default_link_flags": attr.string_list(default = []),
"fastbuild_mode_debug_flag": attr.string(default = ""),
"host_system_name": attr.string(),
"link_flags": attr.string_list(),
"msvc_cl_path": attr.string(default = "vc_installation_error.bat"),
"msvc_env_include": attr.string(default = "msvc_not_found"),
"msvc_env_lib": attr.string(default = "msvc_not_found"),
Expand All @@ -1686,6 +1763,7 @@ cc_toolchain_config = rule(
"tool_bin_path": attr.string(default = "not_found"),
"tool_paths": attr.string_dict(),
"toolchain_identifier": attr.string(),
"win32_winnt_flag": attr.string(default = "/D_WIN32_WINNT=0x0601"),
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@fmeum fmeum Jul 22, 2025

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Can we drop this so that the default isn't maintained in two places?

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@AustinSchuh AustinSchuh Jul 23, 2025

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Happy to, done. Took a bit more code since foo(win32_winnt_flag=None) or foo(win32_winnt_flag="") is different than foo().

},
provides = [CcToolchainConfigInfo],
)