| # pylint: disable=g-bad-file-header |
| # Copyright 2016 The Bazel Authors. All rights reserved. |
| |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| """Configuring the C++ toolchain on Unix platforms.""" |
| |
| load( |
| "@bazel_tools//tools/cpp:lib_cc_configure.bzl", |
| "auto_configure_fail", |
| "auto_configure_warning", |
| "auto_configure_warning_maybe", |
| "escape_string", |
| "execute", |
| "get_env_var", |
| "get_starlark_list", |
| "resolve_labels", |
| "split_escaped", |
| "which", |
| "write_builtin_include_directory_paths", |
| ) |
| |
| def _uniq(iterable): |
| """Remove duplicates from a list.""" |
| |
| unique_elements = {element: None for element in iterable} |
| return unique_elements.keys() |
| |
| def _generate_system_module_map(repository_ctx, dirs, script_path): |
| return execute(repository_ctx, [script_path] + dirs) |
| |
| def _prepare_include_path(repo_ctx, path): |
| """Resolve include path before outputting it into the crosstool. |
| |
| Args: |
| repo_ctx: repository_ctx object. |
| path: an include path to be resolved. |
| |
| Returns: |
| Resolved include path. Resulting path is absolute if it is outside the |
| repository and relative otherwise. |
| """ |
| |
| repo_root = str(repo_ctx.path(".")) |
| |
| # We're on UNIX, so the path delimiter is '/'. |
| repo_root += "/" |
| path = str(repo_ctx.path(path)) |
| if path.startswith(repo_root): |
| return path[len(repo_root):] |
| return path |
| |
| def _get_value(it): |
| """Convert `it` in serialized protobuf format.""" |
| if type(it) == "int": |
| return str(it) |
| elif type(it) == "bool": |
| return "true" if it else "false" |
| else: |
| return "\"%s\"" % it |
| |
| def _find_tool(repository_ctx, tool, overriden_tools): |
| """Find a tool for repository, taking overridden tools into account.""" |
| if tool in overriden_tools: |
| return overriden_tools[tool] |
| return which(repository_ctx, tool, "/usr/bin/" + tool) |
| |
| def _get_tool_paths(repository_ctx, overriden_tools): |
| """Compute the %-escaped path to the various tools""" |
| return dict({ |
| k: escape_string(_find_tool(repository_ctx, k, overriden_tools)) |
| for k in [ |
| "ar", |
| "ld", |
| "llvm-cov", |
| "llvm-profdata", |
| "cpp", |
| "gcc", |
| "dwp", |
| "gcov", |
| "nm", |
| "objcopy", |
| "objdump", |
| "strip", |
| ] |
| }.items()) |
| |
| def _escaped_cplus_include_paths(repository_ctx): |
| """Use ${CPLUS_INCLUDE_PATH} to compute the %-escaped list of flags for cxxflag.""" |
| if "CPLUS_INCLUDE_PATH" in repository_ctx.os.environ: |
| result = [] |
| for p in repository_ctx.os.environ["CPLUS_INCLUDE_PATH"].split(":"): |
| p = escape_string(str(repository_ctx.path(p))) # Normalize the path |
| result.append("-I" + p) |
| return result |
| else: |
| return [] |
| |
| _INC_DIR_MARKER_BEGIN = "#include <...>" |
| |
| # OSX add " (framework directory)" at the end of line, strip it. |
| _OSX_FRAMEWORK_SUFFIX = " (framework directory)" |
| _OSX_FRAMEWORK_SUFFIX_LEN = len(_OSX_FRAMEWORK_SUFFIX) |
| |
| def _cxx_inc_convert(path): |
| """Convert path returned by cc -E xc++ in a complete path. Doesn't %-escape the path!""" |
| path = path.strip() |
| if path.endswith(_OSX_FRAMEWORK_SUFFIX): |
| path = path[:-_OSX_FRAMEWORK_SUFFIX_LEN].strip() |
| return path |
| |
| def _get_cxx_include_directories(repository_ctx, print_resource_dir_supported, cc, lang_flag, additional_flags = []): |
| """Compute the list of C++ include directories.""" |
| result = repository_ctx.execute([cc, "-E", lang_flag, "-", "-v"] + additional_flags) |
| index1 = result.stderr.find(_INC_DIR_MARKER_BEGIN) |
| if index1 == -1: |
| return [] |
| index1 = result.stderr.find("\n", index1) |
| if index1 == -1: |
| return [] |
| index2 = result.stderr.rfind("\n ") |
| if index2 == -1 or index2 < index1: |
| return [] |
| index2 = result.stderr.find("\n", index2 + 1) |
| if index2 == -1: |
| inc_dirs = result.stderr[index1 + 1:] |
| else: |
| inc_dirs = result.stderr[index1 + 1:index2].strip() |
| |
| inc_directories = [ |
| _prepare_include_path(repository_ctx, _cxx_inc_convert(p)) |
| for p in inc_dirs.split("\n") |
| ] |
| |
| if print_resource_dir_supported: |
| resource_dir = repository_ctx.execute( |
| [cc, "-print-resource-dir"] + additional_flags, |
| ).stdout.strip() + "/share" |
| inc_directories.append(_prepare_include_path(repository_ctx, resource_dir)) |
| |
| return inc_directories |
| |
| def _is_compiler_option_supported(repository_ctx, cc, option): |
| """Checks that `option` is supported by the C compiler. Doesn't %-escape the option.""" |
| result = repository_ctx.execute([ |
| cc, |
| option, |
| "-o", |
| "/dev/null", |
| "-c", |
| str(repository_ctx.path("tools/cpp/empty.cc")), |
| ]) |
| return result.stderr.find(option) == -1 |
| |
| def _is_linker_option_supported(repository_ctx, cc, force_linker_flags, option, pattern): |
| """Checks that `option` is supported by the C linker. Doesn't %-escape the option.""" |
| result = repository_ctx.execute([cc] + force_linker_flags + [ |
| option, |
| "-o", |
| "/dev/null", |
| str(repository_ctx.path("tools/cpp/empty.cc")), |
| ]) |
| return result.stderr.find(pattern) == -1 |
| |
| def _find_linker_path(repository_ctx, cc, linker, is_clang): |
| """Checks if a given linker is supported by the C compiler. |
| |
| Args: |
| repository_ctx: repository_ctx. |
| cc: path to the C compiler. |
| linker: linker to find |
| is_clang: whether the compiler is known to be clang |
| |
| Returns: |
| String to put as value to -fuse-ld= flag, or None if linker couldn't be found. |
| """ |
| result = repository_ctx.execute([ |
| cc, |
| str(repository_ctx.path("tools/cpp/empty.cc")), |
| "-o", |
| "/dev/null", |
| # Some macOS clang versions don't fail when setting -fuse-ld=gold, adding |
| # these lines to force it to. This also means that we will not detect |
| # gold when only a very old (year 2010 and older) is present. |
| "-Wl,--start-lib", |
| "-Wl,--end-lib", |
| "-fuse-ld=" + linker, |
| "-v", |
| ]) |
| if result.return_code != 0: |
| return None |
| |
| if not is_clang: |
| return linker |
| |
| # Extract linker path from: |
| # /usr/bin/clang ... |
| # "/usr/bin/ld.lld" -pie -z ... |
| linker_command = result.stderr.splitlines()[-1] |
| return linker_command.strip().split(" ")[0].strip("\"'") |
| |
| def _add_compiler_option_if_supported(repository_ctx, cc, option): |
| """Returns `[option]` if supported, `[]` otherwise. Doesn't %-escape the option.""" |
| return [option] if _is_compiler_option_supported(repository_ctx, cc, option) else [] |
| |
| def _add_linker_option_if_supported(repository_ctx, cc, force_linker_flags, option, pattern): |
| """Returns `[option]` if supported, `[]` otherwise. Doesn't %-escape the option.""" |
| return [option] if _is_linker_option_supported(repository_ctx, cc, force_linker_flags, option, pattern) else [] |
| |
| def _get_no_canonical_prefixes_opt(repository_ctx, cc): |
| # If the compiler sometimes rewrites paths in the .d files without symlinks |
| # (ie when they're shorter), it confuses Bazel's logic for verifying all |
| # #included header files are listed as inputs to the action. |
| |
| # The '-fno-canonical-system-headers' should be enough, but clang does not |
| # support it, so we also try '-no-canonical-prefixes' if first option does |
| # not work. |
| opt = _add_compiler_option_if_supported( |
| repository_ctx, |
| cc, |
| "-fno-canonical-system-headers", |
| ) |
| if len(opt) == 0: |
| return _add_compiler_option_if_supported( |
| repository_ctx, |
| cc, |
| "-no-canonical-prefixes", |
| ) |
| return opt |
| |
| def get_env(repository_ctx): |
| """Convert the environment in a list of export if in Homebrew. Doesn't %-escape the result!""" |
| env = repository_ctx.os.environ |
| if "HOMEBREW_RUBY_PATH" in env: |
| return "\n".join([ |
| "export %s='%s'" % (k, env[k].replace("'", "'\\''")) |
| for k in env |
| if k != "_" and k.find(".") == -1 |
| ]) |
| else: |
| return "" |
| |
| def _coverage_flags(repository_ctx, darwin): |
| use_llvm_cov = "1" == get_env_var( |
| repository_ctx, |
| "BAZEL_USE_LLVM_NATIVE_COVERAGE", |
| default = "0", |
| enable_warning = False, |
| ) |
| if darwin or use_llvm_cov: |
| compile_flags = '"-fprofile-instr-generate", "-fcoverage-mapping"' |
| link_flags = '"-fprofile-instr-generate"' |
| else: |
| # gcc requires --coverage being passed for compilation and linking |
| # https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options |
| compile_flags = '"--coverage"' |
| link_flags = '"--coverage"' |
| return compile_flags, link_flags |
| |
| def _is_clang(repository_ctx, cc): |
| return "clang" in repository_ctx.execute([cc, "-v"]).stderr |
| |
| def _is_gcc(repository_ctx, cc): |
| # GCC's version output uses the basename of argv[0] as the program name: |
| # https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/gcc.cc;h=158461167951c1b9540322fb19be6a89d6da07fc;hb=HEAD#l8728 |
| cc_stdout = repository_ctx.execute([cc, "--version"]).stdout |
| return cc_stdout.startswith("gcc ") or cc_stdout.startswith("gcc-") |
| |
| def _get_compiler_name(repository_ctx, cc): |
| if _is_clang(repository_ctx, cc): |
| return "clang" |
| if _is_gcc(repository_ctx, cc): |
| return "gcc" |
| return "compiler" |
| |
| def _find_generic(repository_ctx, name, env_name, overriden_tools, warn = False, silent = False): |
| """Find a generic C++ toolchain tool. Doesn't %-escape the result.""" |
| |
| if name in overriden_tools: |
| return overriden_tools[name] |
| |
| result = name |
| env_value = repository_ctx.os.environ.get(env_name) |
| env_value_with_paren = "" |
| if env_value != None: |
| env_value = env_value.strip() |
| if env_value: |
| result = env_value |
| env_value_with_paren = " (%s)" % env_value |
| if result.startswith("/"): |
| # Absolute path, maybe we should make this supported by our which function. |
| return result |
| result = repository_ctx.which(result) |
| if result == None: |
| msg = ("Cannot find %s or %s%s; either correct your path or set the %s" + |
| " environment variable") % (name, env_name, env_value_with_paren, env_name) |
| if warn: |
| if not silent: |
| auto_configure_warning(msg) |
| else: |
| auto_configure_fail(msg) |
| return result |
| |
| def find_cc(repository_ctx, overriden_tools): |
| cc = _find_generic(repository_ctx, "gcc", "CC", overriden_tools) |
| if _is_clang(repository_ctx, cc): |
| # If clang is run through a symlink with -no-canonical-prefixes, it does |
| # not find its own include directory, which includes the headers for |
| # libc++. Resolving the potential symlink here prevents this. |
| result = repository_ctx.execute(["readlink", "-f", cc]) |
| if result.return_code == 0: |
| return result.stdout.strip() |
| return cc |
| |
| def configure_unix_toolchain(repository_ctx, cpu_value, overriden_tools): |
| """Configure C++ toolchain on Unix platforms.""" |
| paths = resolve_labels(repository_ctx, [ |
| "@bazel_tools//tools/cpp:BUILD.tpl", |
| "@bazel_tools//tools/cpp:generate_system_module_map.sh", |
| "@bazel_tools//tools/cpp:armeabi_cc_toolchain_config.bzl", |
| "@bazel_tools//tools/cpp:unix_cc_toolchain_config.bzl", |
| "@bazel_tools//tools/cpp:linux_cc_wrapper.sh.tpl", |
| "@bazel_tools//tools/cpp:osx_cc_wrapper.sh.tpl", |
| ]) |
| |
| repository_ctx.symlink( |
| paths["@bazel_tools//tools/cpp:unix_cc_toolchain_config.bzl"], |
| "cc_toolchain_config.bzl", |
| ) |
| |
| repository_ctx.symlink( |
| paths["@bazel_tools//tools/cpp:armeabi_cc_toolchain_config.bzl"], |
| "armeabi_cc_toolchain_config.bzl", |
| ) |
| |
| repository_ctx.file("tools/cpp/empty.cc", "int main() {}") |
| darwin = cpu_value.startswith("darwin") |
| bsd = cpu_value == "freebsd" or cpu_value == "openbsd" |
| |
| cc = find_cc(repository_ctx, overriden_tools) |
| is_clang = _is_clang(repository_ctx, cc) |
| overriden_tools = dict(overriden_tools) |
| overriden_tools["gcc"] = cc |
| overriden_tools["gcov"] = _find_generic( |
| repository_ctx, |
| "gcov", |
| "GCOV", |
| overriden_tools, |
| warn = True, |
| silent = True, |
| ) |
| overriden_tools["llvm-cov"] = _find_generic( |
| repository_ctx, |
| "llvm-cov", |
| "BAZEL_LLVM_COV", |
| overriden_tools, |
| warn = True, |
| silent = True, |
| ) |
| overriden_tools["llvm-profdata"] = _find_generic( |
| repository_ctx, |
| "llvm-profdata", |
| "BAZEL_LLVM_PROFDATA", |
| overriden_tools, |
| warn = True, |
| silent = True, |
| ) |
| overriden_tools["ar"] = _find_generic( |
| repository_ctx, |
| "ar", |
| "AR", |
| overriden_tools, |
| warn = True, |
| silent = True, |
| ) |
| if darwin: |
| overriden_tools["gcc"] = "cc_wrapper.sh" |
| overriden_tools["ar"] = _find_generic(repository_ctx, "libtool", "LIBTOOL", overriden_tools) |
| auto_configure_warning_maybe(repository_ctx, "CC used: " + str(cc)) |
| tool_paths = _get_tool_paths(repository_ctx, overriden_tools) |
| cc_toolchain_identifier = escape_string(get_env_var( |
| repository_ctx, |
| "CC_TOOLCHAIN_NAME", |
| "local", |
| False, |
| )) |
| |
| cc_wrapper_src = ( |
| "@bazel_tools//tools/cpp:osx_cc_wrapper.sh.tpl" if darwin else "@bazel_tools//tools/cpp:linux_cc_wrapper.sh.tpl" |
| ) |
| repository_ctx.template( |
| "cc_wrapper.sh", |
| paths[cc_wrapper_src], |
| { |
| "%{cc}": escape_string(str(cc)), |
| "%{env}": escape_string(get_env(repository_ctx)), |
| }, |
| ) |
| |
| conly_opts = split_escaped(get_env_var( |
| repository_ctx, |
| "BAZEL_CONLYOPTS", |
| "", |
| False, |
| ), ":") |
| |
| cxx_opts = split_escaped(get_env_var( |
| repository_ctx, |
| "BAZEL_CXXOPTS", |
| "-std=c++17", |
| False, |
| ), ":") |
| |
| gold_or_lld_linker_path = ( |
| _find_linker_path(repository_ctx, cc, "lld", is_clang) or |
| _find_linker_path(repository_ctx, cc, "gold", is_clang) |
| ) |
| cc_path = repository_ctx.path(cc) |
| if not str(cc_path).startswith(str(repository_ctx.path(".")) + "/"): |
| # cc is outside the repository, set -B |
| bin_search_flags = ["-B" + escape_string(str(cc_path.dirname))] |
| else: |
| # cc is inside the repository, don't set -B. |
| bin_search_flags = [] |
| if not gold_or_lld_linker_path: |
| ld_path = repository_ctx.path(tool_paths["ld"]) |
| if ld_path.dirname != cc_path.dirname: |
| bin_search_flags.append("-B" + str(ld_path.dirname)) |
| force_linker_flags = [] |
| if gold_or_lld_linker_path: |
| force_linker_flags.append("-fuse-ld=" + gold_or_lld_linker_path) |
| |
| # TODO: It's unclear why these flags aren't added on macOS. |
| if bin_search_flags and not darwin: |
| force_linker_flags.extend(bin_search_flags) |
| use_libcpp = darwin or bsd |
| is_as_needed_supported = _is_linker_option_supported( |
| repository_ctx, |
| cc, |
| force_linker_flags, |
| "-Wl,-no-as-needed", |
| "-no-as-needed", |
| ) |
| is_push_state_supported = _is_linker_option_supported( |
| repository_ctx, |
| cc, |
| force_linker_flags, |
| "-Wl,--push-state", |
| "--push-state", |
| ) |
| if use_libcpp: |
| bazel_default_libs = ["-lc++", "-lm"] |
| else: |
| bazel_default_libs = ["-lstdc++", "-lm"] |
| if is_as_needed_supported and is_push_state_supported: |
| # Do not link against C++ standard libraries unless they are actually |
| # used. |
| # We assume that --push-state support implies --pop-state support. |
| bazel_linklibs_elements = [ |
| arg |
| for lib in bazel_default_libs |
| for arg in ["-Wl,--push-state,-as-needed", lib, "-Wl,--pop-state"] |
| ] |
| else: |
| bazel_linklibs_elements = bazel_default_libs |
| bazel_linklibs = ":".join(bazel_linklibs_elements) |
| bazel_linkopts = "" |
| |
| link_opts = split_escaped(get_env_var( |
| repository_ctx, |
| "BAZEL_LINKOPTS", |
| bazel_linkopts, |
| False, |
| ), ":") |
| link_libs = split_escaped(get_env_var( |
| repository_ctx, |
| "BAZEL_LINKLIBS", |
| bazel_linklibs, |
| False, |
| ), ":") |
| coverage_compile_flags, coverage_link_flags = _coverage_flags(repository_ctx, darwin) |
| print_resource_dir_supported = _is_compiler_option_supported( |
| repository_ctx, |
| cc, |
| "-print-resource-dir", |
| ) |
| no_canonical_prefixes_opt = _get_no_canonical_prefixes_opt(repository_ctx, cc) |
| builtin_include_directories = _uniq( |
| _get_cxx_include_directories(repository_ctx, print_resource_dir_supported, cc, "-xc", conly_opts) + |
| _get_cxx_include_directories(repository_ctx, print_resource_dir_supported, cc, "-xc++", cxx_opts) + |
| _get_cxx_include_directories( |
| repository_ctx, |
| print_resource_dir_supported, |
| cc, |
| "-xc++", |
| cxx_opts + ["-stdlib=libc++"], |
| ) + |
| _get_cxx_include_directories( |
| repository_ctx, |
| print_resource_dir_supported, |
| cc, |
| "-xc", |
| no_canonical_prefixes_opt, |
| ) + |
| _get_cxx_include_directories( |
| repository_ctx, |
| print_resource_dir_supported, |
| cc, |
| "-xc++", |
| cxx_opts + no_canonical_prefixes_opt, |
| ) + |
| _get_cxx_include_directories( |
| repository_ctx, |
| print_resource_dir_supported, |
| cc, |
| "-xc++", |
| cxx_opts + no_canonical_prefixes_opt + ["-stdlib=libc++"], |
| ) + |
| # Always included in case the user has Xcode + the CLT installed, both |
| # paths can be used interchangeably |
| ["/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"], |
| ) |
| |
| generate_modulemap = is_clang and not darwin |
| if generate_modulemap: |
| repository_ctx.file("module.modulemap", _generate_system_module_map( |
| repository_ctx, |
| builtin_include_directories, |
| paths["@bazel_tools//tools/cpp:generate_system_module_map.sh"], |
| )) |
| |
| write_builtin_include_directory_paths(repository_ctx, cc, builtin_include_directories) |
| repository_ctx.template( |
| "BUILD", |
| paths["@bazel_tools//tools/cpp:BUILD.tpl"], |
| { |
| "%{cc_toolchain_identifier}": cc_toolchain_identifier, |
| "%{name}": cpu_value, |
| "%{modulemap}": ("\":module.modulemap\"" if generate_modulemap else "None"), |
| "%{cc_compiler_deps}": get_starlark_list([":builtin_include_directory_paths"] + ( |
| [":cc_wrapper"] if darwin else [] |
| )), |
| "%{compiler}": escape_string(get_env_var( |
| repository_ctx, |
| "BAZEL_COMPILER", |
| _get_compiler_name(repository_ctx, cc), |
| False, |
| )), |
| "%{abi_version}": escape_string(get_env_var( |
| repository_ctx, |
| "ABI_VERSION", |
| "local", |
| False, |
| )), |
| "%{abi_libc_version}": escape_string(get_env_var( |
| repository_ctx, |
| "ABI_LIBC_VERSION", |
| "local", |
| False, |
| )), |
| "%{host_system_name}": escape_string(get_env_var( |
| repository_ctx, |
| "BAZEL_HOST_SYSTEM", |
| "local", |
| False, |
| )), |
| "%{target_libc}": "macosx" if darwin else escape_string(get_env_var( |
| repository_ctx, |
| "BAZEL_TARGET_LIBC", |
| "local", |
| False, |
| )), |
| "%{target_cpu}": escape_string(get_env_var( |
| repository_ctx, |
| "BAZEL_TARGET_CPU", |
| cpu_value, |
| False, |
| )), |
| "%{target_system_name}": escape_string(get_env_var( |
| repository_ctx, |
| "BAZEL_TARGET_SYSTEM", |
| "local", |
| False, |
| )), |
| "%{tool_paths}": ",\n ".join( |
| ['"%s": "%s"' % (k, v) for k, v in tool_paths.items() if v != None], |
| ), |
| "%{cxx_builtin_include_directories}": get_starlark_list(builtin_include_directories), |
| "%{compile_flags}": get_starlark_list( |
| [ |
| "-fstack-protector", |
| # All warnings are enabled. |
| "-Wall", |
| # Enable a few more warnings that aren't part of -Wall. |
| ] + (( |
| _add_compiler_option_if_supported(repository_ctx, cc, "-Wthread-safety") + |
| _add_compiler_option_if_supported(repository_ctx, cc, "-Wself-assign") |
| )) + ( |
| # Disable problematic warnings. |
| _add_compiler_option_if_supported(repository_ctx, cc, "-Wunused-but-set-parameter") + |
| # has false positives |
| _add_compiler_option_if_supported(repository_ctx, cc, "-Wno-free-nonheap-object") + |
| # Enable coloring even if there's no attached terminal. Bazel removes the |
| # escape sequences if --nocolor is specified. |
| _add_compiler_option_if_supported(repository_ctx, cc, "-fcolor-diagnostics") |
| ) + [ |
| # Keep stack frames for debugging, even in opt mode. |
| "-fno-omit-frame-pointer", |
| ], |
| ), |
| "%{cxx_flags}": get_starlark_list(cxx_opts + _escaped_cplus_include_paths(repository_ctx)), |
| "%{conly_flags}": get_starlark_list(conly_opts), |
| "%{link_flags}": get_starlark_list(force_linker_flags + ( |
| ["-Wl,-no-as-needed"] if is_as_needed_supported else [] |
| ) + _add_linker_option_if_supported( |
| repository_ctx, |
| cc, |
| force_linker_flags, |
| "-Wl,-z,relro,-z,now", |
| "-z", |
| ) + ( |
| [ |
| "-headerpad_max_install_names", |
| ] if darwin else [ |
| # Gold linker only? Can we enable this by default? |
| # "-Wl,--warn-execstack", |
| # "-Wl,--detect-odr-violations" |
| ] + _add_compiler_option_if_supported( |
| # Have gcc return the exit code from ld. |
| repository_ctx, |
| cc, |
| "-pass-exit-codes", |
| ) |
| ) + link_opts), |
| "%{link_libs}": get_starlark_list(link_libs), |
| "%{opt_compile_flags}": get_starlark_list( |
| [ |
| # No debug symbols. |
| # Maybe we should enable https://gcc.gnu.org/wiki/DebugFission for opt or |
| # even generally? However, that can't happen here, as it requires special |
| # handling in Bazel. |
| "-g0", |
| |
| # Conservative choice for -O |
| # -O3 can increase binary size and even slow down the resulting binaries. |
| # Profile first and / or use FDO if you need better performance than this. |
| "-O2", |
| |
| # Security hardening on by default. |
| # Conservative choice; -D_FORTIFY_SOURCE=2 may be unsafe in some cases. |
| "-D_FORTIFY_SOURCE=1", |
| |
| # Disable assertions |
| "-DNDEBUG", |
| |
| # Removal of unused code and data at link time (can this increase binary |
| # size in some cases?). |
| "-ffunction-sections", |
| "-fdata-sections", |
| ], |
| ), |
| "%{opt_link_flags}": get_starlark_list( |
| ["-Wl,-dead_strip"] if darwin else _add_linker_option_if_supported( |
| repository_ctx, |
| cc, |
| force_linker_flags, |
| "-Wl,--gc-sections", |
| "-gc-sections", |
| ), |
| ), |
| "%{unfiltered_compile_flags}": get_starlark_list( |
| _get_no_canonical_prefixes_opt(repository_ctx, cc) + [ |
| # Make C++ compilation deterministic. Use linkstamping instead of these |
| # compiler symbols. |
| "-Wno-builtin-macro-redefined", |
| "-D__DATE__=\\\"redacted\\\"", |
| "-D__TIMESTAMP__=\\\"redacted\\\"", |
| "-D__TIME__=\\\"redacted\\\"", |
| ], |
| ), |
| "%{dbg_compile_flags}": get_starlark_list(["-g"]), |
| "%{coverage_compile_flags}": coverage_compile_flags, |
| "%{coverage_link_flags}": coverage_link_flags, |
| "%{supports_start_end_lib}": "True" if gold_or_lld_linker_path else "False", |
| }, |
| ) |
