cc_common

Utilities for C++ compilation, linking, and command line generation.

Members

• action_is_enabled
• CcToolchainInfo
• compile
• configure_features
• create_cc_toolchain_config_info
• create_compilation_context
• create_compilation_outputs
• create_compile_variables
• create_library_to_link
• create_link_variables
• create_linker_input
• create_linking_context
• create_linking_context_from_compilation_outputs
• create_lto_compilation_context
• do_not_use_tools_cpp_compiler_present
• get_environment_variables
• get_execution_requirements
• get_memory_inefficient_command_line
• get_tool_for_action
• is_enabled
• link
• merge_cc_infos
• merge_compilation_contexts
• merge_compilation_outputs

action_is_enabled

bool cc_common.action_is_enabled(*, feature_configuration, action_name)

Returns True if given action_config is enabled in the feature configuration.

Parameters

Parameter	Description
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
action_name	string; required Name of the action_config.

CcToolchainInfo

Provider cc_common.CcToolchainInfo

The key used to retrieve the provider that contains information about the C++ toolchain being used

compile

tuple cc_common.compile(*, actions, feature_configuration, cc_toolchain, srcs=[], public_hdrs=[], private_hdrs=[], includes=[], local_includes=[], quote_includes=[], system_includes=[], framework_includes=[], defines=[], local_defines=[], include_prefix='', strip_include_prefix='', user_compile_flags=[], conly_flags=[], cxx_flags=[], compilation_contexts=[], progress_message_prefix, name, disallow_pic_outputs=False, disallow_nopic_outputs=False, additional_inputs=[], module_interfaces=unbound)

Should be used for C++ compilation. Returns tuple of (CompilationContext, CcCompilationOutputs).

Parameters

Parameter	Description
actions	actions; required actions object.
feature_configuration	FeatureConfiguration; required feature_configuration to be queried.
cc_toolchain	Info; required CcToolchainInfo provider to be used.
srcs	sequence; default is [] The list of source files to be compiled.
public_hdrs	sequence; default is [] List of headers needed for compilation of srcs and may be included by dependent rules transitively.
private_hdrs	sequence; default is [] List of headers needed for compilation of srcs and NOT to be included by dependent rules.
includes	sequence; or depset; default is [] Search paths for header files referenced both by angle bracket and quotes. Usually passed with -I. Propagated to dependents transitively.
local_includes	sequence; or depset; default is [] Search paths for header files referenced by angle brackets and quotes. Usually passed with -I. Not propagated to dependents transitively.
quote_includes	sequence; default is [] Search paths for header files referenced by quotes, e.g. #include “foo/bar/header.h”. They can be either relative to the exec root or absolute. Usually passed with -iquote. Propagated to dependents transitively.
system_includes	sequence; default is [] Search paths for header files referenced by angle brackets, e.g. #include <foo/bar/header.h>. They can be either relative to the exec root or absolute. Usually passed with -isystem. Propagated to dependents transitively.
framework_includes	sequence; default is [] Search paths for header files from Apple frameworks. They can be either relative to the exec root or absolute. Usually passed with -F. Propagated to dependents transitively.
defines	sequence; default is [] Set of defines needed to compile this target. Each define is a string. Propagated to dependents transitively.
local_defines	sequence; default is [] Set of defines needed to compile this target. Each define is a string. Not propagated to dependents transitively.
include_prefix	string; default is '' The prefix to add to the paths of the headers of this rule. When set, the headers in the hdrs attribute of this rule are accessible at is the value of this attribute prepended to their repository-relative path. The prefix in the strip_include_prefix attribute is removed before this prefix is added.
strip_include_prefix	string; default is '' The prefix to strip from the paths of the headers of this rule. When set, the headers in the hdrs attribute of this rule are accessible at their path with this prefix cut off. If it’s a relative path, it’s taken as a package-relative one. If it’s an absolute one, it’s understood as a repository-relative path. The prefix in the include_prefix attribute is added after this prefix is stripped.
user_compile_flags	sequence; default is [] Additional list of compilation options.
conly_flags	sequence; default is [] Additional list of compilation options for C compiles.
cxx_flags	sequence; default is [] Additional list of compilation options for C++ compiles.
compilation_contexts	sequence; default is [] Headers from dependencies used for compilation.
progress_message_prefix	string; or None; required An additional string to identify actions for logging.
name	string; required This is used for naming the output artifacts of actions created by this method. See also the main_output arg.
disallow_pic_outputs	bool; default is False Whether PIC outputs should be created.
disallow_nopic_outputs	bool; default is False Whether NOPIC outputs should be created.
additional_inputs	sequence; default is [] List of additional files needed for compilation of srcs
module_interfaces	sequence; default is unbound The list of module interfaces source files to be compiled. Note: this is an experimental feature, only enabled with —experimental_cpp_modules

configure_features

FeatureConfiguration cc_common.configure_features(*, ctx, cc_toolchain, language=None, requested_features=[], unsupported_features=[])

Creates a feature_configuration instance. Requires the cpp configuration fragment.

Parameters

Parameter	Description
ctx	ctx; required The rule context.
cc_toolchain	Info; required cc_toolchain for which we configure features.
language	string; or None; default is None The language to configure for: either c++ or objc (default c++)
requested_features	sequence; default is [] List of features to be enabled.
unsupported_features	sequence; default is [] List of features that are unsupported by the current rule.

create_cc_toolchain_config_info

None cc_common.create_cc_toolchain_config_info(*, ctx, features=[], action_configs=[], artifact_name_patterns=[], cxx_builtin_include_directories=[], toolchain_identifier, host_system_name=None, target_system_name=None, target_cpu=None, target_libc=None, compiler, abi_version=None, abi_libc_version=None, tool_paths=[], make_variables=[], builtin_sysroot=None)

Creates a CcToolchainConfigInfo provider

Parameters

Parameter	Description
ctx	ctx; required The rule context.
features	sequence; default is [] Contains all flag specifications for one feature. Arguments: name: The feature’s name. It is possible to introduce a feature without a change to Bazel by adding a ‘feature’ section to the toolchain and adding the corresponding string as feature in the BUILD file. enabled: If ‘True’, this feature is enabled unless a rule type explicitly marks it as unsupported. flag_sets: A FlagSet list. If the given feature is enabled, the flag sets will be applied for the actions are specified for. env_sets: an EnvSet list. If the given feature is enabled, the env sets will be applied for the actions they are specified for. requires: A list of feature sets defining when this feature is supported by the toolchain. The feature is supported if any of the feature sets fully apply, that is, when all features of a feature set are enabled. If requires is omitted, the feature is supported independently of which other features are enabled. Use this for example to filter flags depending on the build mode enabled (opt / fastbuild / dbg). implies: A string list of features or action configs that are automatically enabled when this feature is enabled. If any of the implied features or action configs cannot be enabled, this feature will (silently) not be enabled either. provides: A list of names this feature conflicts with. A feature cannot be enabled if:- provides contains the name of a different feature or action config that we want to enable.- provides contains the same value as a ‘provides’ in a different feature or action config that we want to enable. Use this in order to ensure that incompatible features cannot be accidentally activated at the same time, leading to hard to diagnose compiler errors.
action_configs	sequence; default is [] An action config corresponds to a Bazel action, and allows selection of a tool based on activated features. Action config activation occurs by the same semantics as features: a feature can ‘require’ or ‘imply’ an action config in the same way that it would another feature. Arguments: action_name: The name of the Bazel action that this config applies to, e.g. ‘c-compile’ or ‘c-module-compile’. enabled: If ‘True’, this action is enabled unless a rule type explicitly marks it as unsupported. tools: The tool applied to the action will be the first tool with a feature set that matches the feature configuration. An error will be thrown if no tool matches a provided feature configuration - for that reason, it’s a good idea to provide a default tool with an empty feature set. flag_sets: If the given action config is enabled, the flag sets will be applied to the corresponding action. implies: A list of features or action configs that are automatically enabled when this action config is enabled. If any of the implied features or action configs cannot be enabled, this action config will (silently) not be enabled either.
artifact_name_patterns	sequence; default is [] The name for an artifact of a given category of input or output artifacts to an action. Arguments: category_name: The category of artifacts that this selection applies to. This field is compared against a list of categories defined in Bazel. Example categories include “linked_output” or the artifact for this selection. Together with the extension it is used to create an artifact name based on the target name. extension: The extension for creating the artifact for this selection. Together with the prefix it is used to create an artifact name based on the target name.
cxx_builtin_include_directories	sequence; default is [] Built-in include directories for C++ compilation. These should be the exact paths used by the compiler, and are generally relative to the exec root. The paths used by the compiler can be determined by ‘gcc -E -xc++ - -v’. We currently use the C++ paths also for C compilation, which is safe as long as there are no name clashes between C++ and C header files. Relative paths are resolved relative to the configuration file directory. If the compiler has —sysroot support, then these paths should use %sysroot% rather than the include path, and specify the sysroot attribute in order to give blaze the information necessary to make the correct replacements.
toolchain_identifier	string; required The unique identifier of the toolchain within the crosstool release. It must be possible to use this as a directory name in a path. It has to match the following regex: [a-zA-Z_][.- \w]*
host_system_name	string; or None; default is None Ignored.
target_system_name	string; or None; default is None Deprecated. The GNU System Name. The string is exposed to CcToolchainInfo.target_gnu_system_name.
target_cpu	string; or None; default is None Deprecated: Use cpu based constraints instead. If the string is “k8”, target_cpu will be omitted from the filename of raw FDO profile data.
target_libc	string; or None; default is None Deprecated: Use OS based constraints instead. The libc version string (e.g. “glibc-2.2.2”). If the string is “macosx”, platform is assumed to be MacOS. Otherwise, Linux. The string is exposed to CcToolchainInfo.libc.
compiler	string; required The compiler string (e.g. “gcc”). The current toolchain’s compiler is exposed to @bazel_tools//tools/cpp:compiler (compiler_flag) as a flag value. Targets that require compiler-specific flags can use the config_settings in https://github.com/bazelbuild/rules_cc/blob/main/cc/compiler/BUILD in select() statements or create custom config_setting if the existing settings don’t suffice.
abi_version	string; or None; default is None The abi in use, which is a gcc version. E.g.: “gcc-3.4”. The string is set to C++ toolchain variable ABI.
abi_libc_version	string; or None; default is None The glibc version used by the abi we’re using. The string is set to C++ toolchain variable ABI_LIBC_VERSION.
tool_paths	sequence; default is [] Tool locations. Arguments: name: Name of the tool. path: Location of the tool; Can be absolute path (in case of non hermetic toolchain), or path relative to the cc_toolchain’s package.
make_variables	sequence; default is [] A make variable that is made accessible to rules.
builtin_sysroot	string; or None; default is None The built-in sysroot. If this attribute is not present, Bazel does not allow using a different sysroot, i.e. through the —grte_top option.

create_compilation_context

CompilationContext cc_common.create_compilation_context(*, headers=unbound, system_includes=unbound, includes=unbound, quote_includes=unbound, framework_includes=unbound, defines=unbound, local_defines=unbound)

Creates a CompilationContext.

Parameters

Parameter	Description
headers	default is unbound Set of headers needed to compile this target
system_includes	default is unbound Set of search paths for header files referenced by angle brackets, i.e. #include <foo/bar/header.h>. They can be either relative to the exec root or absolute. Usually passed with -isystem
includes	default is unbound Set of search paths for header files referenced both by angle bracket and quotes.Usually passed with -I
quote_includes	default is unbound Set of search paths for header files referenced by quotes, i.e. #include “foo/bar/header.h”. They can be either relative to the exec root or absolute. Usually passed with -iquote
framework_includes	default is unbound Set of framework search paths for header files (Apple platform only)
defines	default is unbound Set of defines needed to compile this target. Each define is a string. Propagated transitively to dependents.
local_defines	default is unbound Set of defines needed to compile this target. Each define is a string. Not propagated transitively to dependents.

create_compilation_outputs

CcCompilationOutputs cc_common.create_compilation_outputs(*, objects=None, pic_objects=None)

Create compilation outputs object.

Parameters

Parameter	Description
objects	depset; or None; default is None List of object files.
pic_objects	depset; or None; default is None List of pic object files.

create_compile_variables

Variables cc_common.create_compile_variables(*, cc_toolchain, feature_configuration, source_file=None, output_file=None, user_compile_flags=None, include_directories=None, quote_include_directories=None, system_include_directories=None, framework_include_directories=None, preprocessor_defines=None, thinlto_index=None, thinlto_input_bitcode_file=None, thinlto_output_object_file=None, use_pic=False, add_legacy_cxx_options=False, variables_extension=unbound)

Returns variables used for compilation actions.

Parameters

Parameter	Description
cc_toolchain	Info; required cc_toolchain for which we are creating build variables.
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
source_file	File; or string; or None; default is None Optional source file path for the compilation. Please prefer passing source_file here over appending it to the end of the command line generated from cc_common.get_memory_inefficient_command_line, as then it’s in the power of the toolchain author to properly specify and position compiler flags.
output_file	File; or string; or None; default is None Optional output file path of the compilation. Please prefer passing output_file here over appending it to the end of the command line generated from cc_common.get_memory_inefficient_command_line, as then it’s in the power of the toolchain author to properly specify and position compiler flags.
user_compile_flags	sequence of strings; or None; default is None List of additional compilation flags (copts).
include_directories	depset; or None; default is None Depset of include directories.
quote_include_directories	depset; or None; default is None Depset of quote include directories.
system_include_directories	depset; or None; default is None Depset of system include directories.
framework_include_directories	depset; or None; default is None Depset of framework include directories.
preprocessor_defines	depset; or None; default is None Depset of preprocessor defines.
thinlto_index	string; or None; default is None LTO index file path.
thinlto_input_bitcode_file	string; or None; default is None Bitcode file that is input to LTO backend.
thinlto_output_object_file	string; or None; default is None Object file that is output by LTO backend.
use_pic	bool; default is False When true the compilation will generate position independent code.
add_legacy_cxx_options	bool; default is False Unused.
variables_extension	dict; default is unbound A dictionary of additional variables used by compile actions.

create_library_to_link

LibraryToLink cc_common.create_library_to_link(*, actions, feature_configuration=None, cc_toolchain=None, static_library=None, pic_static_library=None, dynamic_library=None, interface_library=None, pic_objects=unbound, objects=unbound, alwayslink=False, dynamic_library_symlink_path='', interface_library_symlink_path='')

Creates LibraryToLink

Parameters

Parameter	Description
actions	required actions object.
feature_configuration	default is None feature_configuration to be queried.
cc_toolchain	default is None CcToolchainInfo provider to be used.
static_library	File; or None; default is None File of static library to be linked.
pic_static_library	File; or None; default is None File of pic static library to be linked.
dynamic_library	File; or None; default is None File of dynamic library to be linked. Always used for runtime and used for linking if interface_library is not passed.
interface_library	File; or None; default is None File of interface library to be linked.
pic_objects	sequence of Files; default is unbound Experimental, do not use
objects	sequence of Files; default is unbound Experimental, do not use
alwayslink	bool; default is False Whether to link the static library/objects in the —whole_archive block.
dynamic_library_symlink_path	string; default is '' Override the default path of the dynamic library link in the solib directory. Empty string to use the default.
interface_library_symlink_path	string; default is '' Override the default path of the interface library link in the solib directory. Empty string to use the default.

create_link_variables

Variables cc_common.create_link_variables(*, cc_toolchain, feature_configuration, library_search_directories=[], runtime_library_search_directories=[], user_link_flags=[], output_file=None, param_file=None, is_using_linker=True, is_linking_dynamic_library=False, must_keep_debug=True, use_test_only_flags=False, is_static_linking_mode=True)

Returns link variables used for linking actions.

Parameters

Parameter	Description
cc_toolchain	Info; required cc_toolchain for which we are creating build variables.
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
library_search_directories	depset; default is [] Depset of directories where linker will look for libraries at link time.
runtime_library_search_directories	depset; default is [] Depset of directories where loader will look for libraries at runtime.
user_link_flags	sequence; default is [] List of additional link flags (linkopts).
output_file	default is None Optional output file path.
param_file	default is None Optional param file path.
is_using_linker	bool; default is True True when using linker, False when archiver. Caller is responsible for keeping this in sync with action name used (is_using_linker = True for linking executable or dynamic library, is_using_linker = False for archiving static library).
is_linking_dynamic_library	bool; default is False True when creating dynamic library, False when executable or static library. Caller is responsible for keeping this in sync with action name used. This field will be removed once b/65151735 is fixed.
must_keep_debug	bool; default is True When set to False, bazel will expose ‘strip_debug_symbols’ variable, which is usually used to use the linker to strip debug symbols from the output file.
use_test_only_flags	bool; default is False When set to true, ‘is_cc_test’ variable will be set.
is_static_linking_mode	bool; default is True Unused.

create_linker_input

LinkerInput cc_common.create_linker_input(*, owner, libraries=None, user_link_flags=None, additional_inputs=None)

Creates a LinkerInput.

Parameters

Parameter	Description
owner	Label; required The label of the target that produced all files used in this input.
libraries	None; or depset; default is None List of LibraryToLink.
user_link_flags	None; or depset of strings; or sequence of strings; default is None User link flags passed as strings. Accepts either [String], [[String]] or depset(String). The latter is discouraged as it’s only kept for compatibility purposes, the depset is flattened. If you want to propagate user_link_flags via unflattened depsets() wrap them in a LinkerInput so that they are not flattened till the end.
additional_inputs	None; or depset; default is None For additional inputs to the linking action, e.g.: linking scripts.

create_linking_context

LinkingContext cc_common.create_linking_context(*, linker_inputs)

Creates a LinkingContext.

Parameters

Parameter	Description
linker_inputs	depset; required Depset of LinkerInput.

create_linking_context_from_compilation_outputs

tuple cc_common.create_linking_context_from_compilation_outputs(*, actions, name, feature_configuration, cc_toolchain, language='c++', disallow_static_libraries=False, disallow_dynamic_library=False, compilation_outputs, linking_contexts=[], user_link_flags=[], alwayslink=False, additional_inputs=[], variables_extension=unbound)

Should be used for creating library rules that can propagate information downstream in order to be linked later by a top level rule that does transitive linking to create an executable or a dynamic library. Returns tuple of (CcLinkingContext, CcLinkingOutputs).

Parameters

Parameter	Description
actions	actions; required actions object.
name	string; required This is used for naming the output artifacts of actions created by this method.
feature_configuration	FeatureConfiguration; required feature_configuration to be queried.
cc_toolchain	Info; required CcToolchainInfo provider to be used.
language	string; default is 'c++' Only C++ supported for now. Do not use this parameter.
disallow_static_libraries	bool; default is False Whether static libraries should be created.
disallow_dynamic_library	bool; default is False Whether a dynamic library should be created.
compilation_outputs	CcCompilationOutputs; required Compilation outputs containing object files to link.
linking_contexts	sequence; default is [] Libraries from dependencies. These libraries will be linked into the output artifact of the link() call, be it a binary or a library.
user_link_flags	sequence; default is [] Additional list of linking options.
alwayslink	bool; default is False Whether this library should always be linked.
additional_inputs	sequence; default is [] For additional inputs to the linking action, e.g.: linking scripts.
variables_extension	dict; default is unbound Additional variables to pass to the toolchain configuration when creating link command line.

create_lto_compilation_context

LtoCompilationContext cc_common.create_lto_compilation_context(*, objects={})

Create LTO compilation context

Parameters

Parameter	Description
objects	dict; default is {} map of full object to index object

do_not_use_tools_cpp_compiler_present

None cc_common.do_not_use_tools_cpp_compiler_present

Do not use this field, its only purpose is to help with migration from config_setting.values{‘compiler’) to config_settings.flag_values{‘@bazel_tools//tools/cpp:compiler’}

get_environment_variables

dict cc_common.get_environment_variables(*, feature_configuration, action_name, variables)

Returns environment variables to be set for given action.

Parameters

Parameter	Description
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
action_name	string; required Name of the action. Has to be one of the names in @bazel_tools//tools/build_defs/cc:action_names.bzl (https://github.com/bazelbuild/bazel/blob/master/tools/build_defs/cc/action_names.bzl)
variables	Variables; required Build variables to be used for template expansion.

get_execution_requirements

sequence cc_common.get_execution_requirements(*, feature_configuration, action_name)

Returns execution requirements for given action.

Parameters

Parameter	Description
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
action_name	string; required Name of the action. Has to be one of the names in @bazel_tools//tools/build_defs/cc:action_names.bzl (https://github.com/bazelbuild/bazel/blob/master/tools/build_defs/cc/action_names.bzl)

get_memory_inefficient_command_line

sequence cc_common.get_memory_inefficient_command_line(*, feature_configuration, action_name, variables)

Returns flattened command line flags for given action, using given variables for expansion. Flattens nested sets and ideally should not be used, or at least should not outlive analysis. Work on memory efficient function returning Args is ongoing.

Parameters

Parameter	Description
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
action_name	string; required Name of the action. Has to be one of the names in @bazel_tools//tools/build_defs/cc:action_names.bzl (https://github.com/bazelbuild/bazel/blob/master/tools/build_defs/cc/action_names.bzl)
variables	Variables; required Build variables to be used for template expansions.

get_tool_for_action

string cc_common.get_tool_for_action(*, feature_configuration, action_name)

Returns tool path for given action.

Parameters

Parameter	Description
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
action_name	string; required Name of the action. Has to be one of the names in @bazel_tools//tools/build_defs/cc:action_names.bzl (https://github.com/bazelbuild/bazel/blob/master/tools/build_defs/cc/action_names.bzl)

is_enabled

bool cc_common.is_enabled(*, feature_configuration, feature_name)

Returns True if given feature is enabled in the feature configuration.

Parameters

Parameter	Description
feature_configuration	FeatureConfiguration; required Feature configuration to be queried.
feature_name	string; required Name of the feature.

link

CcLinkingOutputs cc_common.link(*, actions, name, feature_configuration, cc_toolchain, language='c++', output_type='executable', link_deps_statically=True, compilation_outputs=None, linking_contexts=[], user_link_flags=[], stamp=0, additional_inputs=[], additional_outputs=[], variables_extension={})

Should be used for C++ transitive linking.

Parameters

Parameter	Description
actions	actions; required actions object.
name	string; required This is used for naming the output artifacts of actions created by this method.
feature_configuration	FeatureConfiguration; required feature_configuration to be queried.
cc_toolchain	Info; required CcToolchainInfo provider to be used.
language	string; default is 'c++' Only C++ supported for now. Do not use this parameter.
output_type	string; default is 'executable' Can be either ‘executable’ or ‘dynamic_library’.
link_deps_statically	bool; default is True True to link dependencies statically, False dynamically.
compilation_outputs	CcCompilationOutputs; or None; default is None Compilation outputs containing object files to link.
linking_contexts	sequence; default is [] Linking contexts from dependencies to be linked into the linking context generated by this rule.
user_link_flags	sequence; default is [] Additional list of linker options.
stamp	int; default is 0 Whether to include build information in the linked executable, if output_type is ‘executable’. If 1, build information is always included. If 0 (the default build information is always excluded. If -1, uses the default behavior, which may be overridden by the —[no]stamp flag. This should be unset (or set to 0) when generating the executable output for test rules.
additional_inputs	sequence; or depset; default is [] For additional inputs to the linking action, e.g.: linking scripts.
additional_outputs	sequence; default is [] For additional outputs to the linking action, e.g.: map files.
variables_extension	dict; default is {} Additional variables to pass to the toolchain configuration when create link command line.

merge_cc_infos

unknown cc_common.merge_cc_infos(*, direct_cc_infos=[], cc_infos=[])

Merges multiple CcInfos into one.

Parameters

Parameter	Description
direct_cc_infos	sequence; default is [] List of CcInfos to be merged, whose headers will be exported by the direct fields in the returned provider.
cc_infos	sequence; default is [] List of CcInfos to be merged, whose headers will not be exported by the direct fields in the returned provider.

merge_compilation_contexts

CompilationContext cc_common.merge_compilation_contexts(*, compilation_contexts=[])

Merges multiple CompilationContextss into one.

Parameters

Parameter	Description
compilation_contexts	sequence; default is [] List of CompilationContextss to be merged. The headers of each context will be exported by the direct fields in the returned provider.

merge_compilation_outputs

CcCompilationOutputs cc_common.merge_compilation_outputs(*, compilation_outputs=[])

Merge compilation outputs.

Parameters

Parameter	Description
compilation_outputs	sequence; default is []