C / C++ Rules

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Rules

cc_binary
cc_import
cc_library
cc_proto_library
cc_shared_library
fdo_prefetch_hints
fdo_profile
memprof_profile
propeller_optimize
cc_test
cc_toolchain
cc_toolchain_suite

cc_binary

cc_binary(name, deps, srcs, data, additional_linker_inputs, args, compatible_with, copts, defines, deprecation, distribs, env, exec_compatible_with, exec_properties, features, includes, licenses, link_extra_lib, linkopts, linkshared, linkstatic, local_defines, malloc, nocopts, output_licenses, restricted_to, stamp, tags, target_compatible_with, testonly, toolchains, visibility, win_def_file)

Implicit output targets

name.stripped (only built if explicitly requested): A stripped version of the binary. strip -g is run on the binary to remove debug symbols. Additional strip options can be provided on the command line using --stripopt=-foo. This output is only built if explicitly requested.
name.dwp (only built if explicitly requested): If Fission is enabled: a debug information package file suitable for debugging remotely deployed binaries. Else: an empty file.

Arguments

Attributes
`name`	Name; required A unique name for this target.
`deps`	List of labels; default is `[]` The list of other libraries to be linked in to the binary target. These can be `cc_library` or `objc_library` targets.
`srcs`	List of labels; default is `[]` The list of C and C++ files that are processed to create the target. These are C/C++ source and header files, either non-generated (normal source code) or generated. All `.cc`, `.c`, and `.cpp` files will be compiled. These might be generated files: if a named file is in the `outs` of some other rule, this rule will automatically depend on that other rule. A `.h` file will not be compiled, but will be available for inclusion by sources in this rule. Both `.cc` and `.h` files can directly include headers listed in these `srcs` or in the `hdrs` of any rule listed in the `deps` argument. All `#include`d files must be mentioned in the `srcs` attribute of this rule, or in the `hdrs` attribute of referenced `cc_library()`s. The recommended style is for headers associated with a library to be listed in that library's `hdrs` attribute, and any remaining headers associated with this rule's sources to be listed in `srcs`. See "Header inclusion checking" for a more detailed description. If a rule's name is in the `srcs`, then this rule automatically depends on that one. If the named rule's `outs` are C or C++ source files, they are compiled into this rule; if they are library files, they are linked in. Permitted `srcs` file types: C and C++ source files: `.c`, `.cc`, `.cpp`, `.cxx`, `.c++`, `.C` C and C++ header files: `.h`, `.hh`, `.hpp`, `.hxx`, `.inc`, `.inl`, `.H` Assembler with C preprocessor: `.S` Archive: `.a`, `.pic.a` "Always link" library: `.lo`, `.pic.lo` Shared library, versioned or unversioned: `.so`, `.so.version` Object file: `.o`, `.pic.o` ...and any rules that produce those files. Different extensions denote different programming languages in accordance with gcc convention.
`additional_linker_inputs`	List of labels; default is `[]` Pass these files to the C++ linker command. For example, compiled Windows .res files can be provided here to be embedded in the binary target.
`copts`	List of strings; default is `[]` Add these options to the C++ compilation command. Subject to "Make variable" substitution and Bourne shell tokenization. Each string in this attribute is added in the given order to `COPTS` before compiling the binary target. The flags take effect only for compiling this target, not its dependencies, so be careful about header files included elsewhere. All paths should be relative to the workspace, not to the current package. If the package declares the feature `no_copts_tokenization`, Bourne shell tokenization applies only to strings that consist of a single "Make" variable.
`defines`	List of strings; default is `[]` List of defines to add to the compile line. Subject to "Make" variable substitution and Bourne shell tokenization. Each string, which must consist of a single Bourne shell token, is prepended with `-D` and added to the compile command line to this target, as well as to every rule that depends on it. Be very careful, since this may have far-reaching effects. When in doubt, add define values to `local_defines` instead.
`includes`	List of strings; default is `[]` List of include dirs to be added to the compile line. Subject to "Make variable" substitution. Each string is prepended with `-isystem` and added to `COPTS`. Unlike COPTS, these flags are added for this rule and every rule that depends on it. (Note: not the rules it depends upon!) Be very careful, since this may have far-reaching effects. When in doubt, add "-I" flags to COPTS instead. Headers must be added to srcs or hdrs, otherwise they will not be available to dependent rules when compilation is sandboxed (the default).
`link_extra_lib`	Label; default is `"@bazel_tools//tools/cpp:link_extra_lib"` Control linking of extra libraries. By default, C++ binaries are linked against `//tools/cpp:link_extra_lib`, which by default depends on the label flag `//tools/cpp:link_extra_libs`. Without setting the flag, this library is empty by default. Setting the label flag allows linking optional dependencies, such as overrides for weak symbols, interceptors for shared library functions, or special runtime libraries (for malloc replacements, prefer `malloc` or `--custom_malloc`). Setting this attribute to `None` disables this behaviour.
`linkopts`	List of strings; default is `[]` Add these flags to the C++ linker command. Subject to "Make" variable substitution, Bourne shell tokenization and label expansion. Each string in this attribute is added to `LINKOPTS` before linking the binary target. Each element of this list that does not start with `$` or `-` is assumed to be the label of a target in `deps`. The list of files generated by that target is appended to the linker options. An error is reported if the label is invalid, or is not declared in `deps`.
`linkshared`	Boolean; nonconfigurable; default is `False` Create a shared library. To enable this attribute, include `linkshared=True` in your rule. By default this option is off. The presence of this flag means that linking occurs with the `-shared` flag to `gcc`, and the resulting shared library is suitable for loading into for example a Java program. However, for build purposes it will never be linked into the dependent binary, as it is assumed that shared libraries built with a cc_binary rule are only loaded manually by other programs, so it should not be considered a substitute for the cc_library rule. For sake of scalability we recommend avoiding this approach altogether and simply letting `java_library` depend on `cc_library` rules instead. If you specify both `linkopts=['-static']` and `linkshared=True`, you get a single completely self-contained unit. If you specify both `linkstatic=True` and `linkshared=True`, you get a single, mostly self-contained unit.
`linkstatic`	Boolean; default is `True` For `cc_binary` and `cc_test`: link the binary in static mode. For `cc_library.linkstatic`: see below. By default this option is on for `cc_binary` and off for the rest. If enabled and this is a binary or test, this option tells the build tool to link in `.a`'s instead of `.so`'s for user libraries whenever possible. Some system libraries may still be linked dynamically, as are libraries for which there is no static library. So the resulting executable will still be dynamically linked, hence only mostly static. There are really three different ways to link an executable: STATIC with fully_static_link feature, in which everything is linked statically; e.g. "`gcc -static foo.o libbar.a libbaz.a -lm`". This mode is enabled by specifying `fully_static_link` in the `features` attribute. STATIC, in which all user libraries are linked statically (if a static version is available), but where system libraries (excluding C/C++ runtime libraries) are linked dynamically, e.g. "`gcc foo.o libfoo.a libbaz.a -lm`". This mode is enabled by specifying `linkstatic=True`. DYNAMIC, in which all libraries are linked dynamically (if a dynamic version is available), e.g. "`gcc foo.o libfoo.so libbaz.so -lm`". This mode is enabled by specifying `linkstatic=False`. The `linkstatic` attribute has a different meaning if used on a `cc_library()` rule. For a C++ library, `linkstatic=True` indicates that only static linking is allowed, so no `.so` will be produced. linkstatic=False does not prevent static libraries from being created. The attribute is meant to control the creation of dynamic libraries. If `linkstatic=False`, then the build tool will create symlinks to depended-upon shared libraries in the `*.runfiles` area.
`local_defines`	List of strings; default is `[]` List of defines to add to the compile line. Subject to "Make" variable substitution and Bourne shell tokenization. Each string, which must consist of a single Bourne shell token, is prepended with `-D` and added to the compile command line for this target, but not to its dependents.
`malloc`	Label; default is `"@bazel_tools//tools/cpp:malloc"` Override the default dependency on malloc. By default, C++ binaries are linked against `//tools/cpp:malloc`, which is an empty library so the binary ends up using libc malloc. This label must refer to a `cc_library`. If compilation is for a non-C++ rule, this option has no effect. The value of this attribute is ignored if `linkshared=True` is specified.
`nocopts`	String; default is `""` Remove matching options from the C++ compilation command. Subject to "Make" variable substitution. The value of this attribute is interpreted as a regular expression. Any preexisting `COPTS` that match this regular expression (including values explicitly specified in the rule's copts attribute) will be removed from `COPTS` for purposes of compiling this rule. This attribute should rarely be needed.
`stamp`	Integer; default is `-1` Whether to encode build information into the binary. Possible values: `stamp = 1`: Always stamp the build information into the binary, even in `--nostamp` builds. This setting should be avoided, since it potentially kills remote caching for the binary and any downstream actions that depend on it. `stamp = 0`: Always replace build information by constant values. This gives good build result caching. `stamp = -1`: Embedding of build information is controlled by the `--[no]stamp` flag. Stamped binaries are not rebuilt unless their dependencies change.
`win_def_file`	Label; default is `None` The Windows DEF file to be passed to linker. This attribute should only be used when Windows is the target platform. It can be used to export symbols during linking a shared library.

cc_import

View rule source

cc_import(name, deps, data, hdrs, alwayslink, compatible_with, deprecation, distribs, features, interface_library, licenses, restricted_to, shared_library, static_library, system_provided, tags, target_compatible_with, testonly, visibility)

cc_import rules allows users to import precompiled C/C++ libraries.

The following are the typical use cases:
1. Linking a static library

cc_import(
  name = "mylib",
  hdrs = ["mylib.h"],
  static_library = "libmylib.a",
  # If alwayslink is turned on,
  # libmylib.a will be forcely linked into any binary that depends on it.
  # alwayslink = 1,
)

2. Linking a shared library (Unix)

cc_import(
  name = "mylib",
  hdrs = ["mylib.h"],
  shared_library = "libmylib.so",
)

3. Linking a shared library with interface library (Windows)

cc_import(
  name = "mylib",
  hdrs = ["mylib.h"],
  # mylib.lib is an import library for mylib.dll which will be passed to linker
  interface_library = "mylib.lib",
  # mylib.dll will be available for runtime
  shared_library = "mylib.dll",
)

4. Linking a shared library with system_provided=True (Windows)

cc_import(
  name = "mylib",
  hdrs = ["mylib.h"],
  # mylib.lib is an import library for mylib.dll which will be passed to linker
  interface_library = "mylib.lib",
  # mylib.dll is provided by system environment, for example it can be found in PATH.
  # This indicates that Bazel is not responsible for making mylib.dll available.
  system_provided = 1,
)

5. Linking to static or shared library
On Unix:

cc_import(
  name = "mylib",
  hdrs = ["mylib.h"],
  static_library = "libmylib.a",
  shared_library = "libmylib.so",
)

# first will link to libmylib.a
cc_binary(
  name = "first",
  srcs = ["first.cc"],
  deps = [":mylib"],
  linkstatic = 1, # default value
)

# second will link to libmylib.so
cc_binary(
  name = "second",
  srcs = ["second.cc"],
  deps = [":mylib"],
  linkstatic = 0,
)

On Windows:

cc_import(
  name = "mylib",
  hdrs = ["mylib.h"],
  static_library = "libmylib.lib", # A normal static library
  interface_library = "mylib.lib", # An import library for mylib.dll
  shared_library = "mylib.dll",
)

# first will link to libmylib.lib
cc_binary(
  name = "first",
  srcs = ["first.cc"],
  deps = [":mylib"],
  linkstatic = 1, # default value
)

# second will link to mylib.dll through mylib.lib
cc_binary(
  name = "second",
  srcs = ["second.cc"],
  deps = [":mylib"],
  linkstatic = 0,
)

cc_import supports an include attribute. For example:

  cc_import(
  name = "curl_lib",
  hdrs = glob(["vendor/curl/include/curl/*.h"]),
  includes = [ "vendor/curl/include" ],
  shared_library = "vendor/curl/lib/.libs/libcurl.dylib",
)

Arguments

Attributes
`name`	Name; required A unique name for this target.
`deps`	List of labels; default is `[]` The list of other libraries that the target depends upon. See general comments about `deps` at Typical attributes defined by most build rules.
`hdrs`	List of labels; default is `[]` The list of header files published by this precompiled library to be directly included by sources in dependent rules.
`alwayslink`	Boolean; default is `False` If 1, any binary that depends (directly or indirectly) on this C++ precompiled library will link in all the object files archived in the static library, even if some contain no symbols referenced by the binary. This is useful if your code isn't explicitly called by code in the binary, e.g., if your code registers to receive some callback provided by some service. If alwayslink doesn't work with VS 2017 on Windows, that is due to a known issue, please upgrade your VS 2017 to the latest version.
`interface_library`	Label; default is `None` A single interface library for linking the shared library. Permitted file types: `.ifso`, `.tbd`, `.lib`, `.so` or `.dylib`
`shared_library`	Label; default is `None` A single precompiled shared library. Bazel ensures it is available to the binary that depends on it during runtime. Permitted file types: `.so`, `.dll` or `.dylib`
`static_library`	Label; default is `None` A single precompiled static library. Permitted file types: `.a`, `.pic.a` or `.lib`
`system_provided`	Boolean; default is `False` If 1, it indicates the shared library required at runtime is provided by the system. In this case, `interface_library` should be specified and `shared_library` should be empty.

cc_library

View rule source

cc_library(name, deps, srcs, data, hdrs, additional_compiler_inputs, additional_linker_inputs, alwayslink, compatible_with, copts, defines, deprecation, distribs, exec_compatible_with, exec_properties, features, implementation_deps, include_prefix, includes, licenses, linkopts, linkstamp, linkstatic, local_defines, nocopts, restricted_to, strip_include_prefix, tags, target_compatible_with, testonly, textual_hdrs, toolchains, visibility, win_def_file)

Header inclusion checking

All header files that are used in the build must be declared in the hdrs or srcs of cc_* rules. This is enforced.

For cc_library rules, headers in hdrs comprise the public interface of the library and can be directly included both from the files in hdrs and srcs of the library itself as well as from files in hdrs and srcs of cc_* rules that list the library in their deps. Headers in srcs must only be directly included from the files in hdrs and srcs of the library itself. When deciding whether to put a header into hdrs or srcs, you should ask whether you want consumers of this library to be able to directly include it. This is roughly the same decision as between public and private visibility in programming languages.

cc_binary and cc_test rules do not have an exported interface, so they also do not have a hdrs attribute. All headers that belong to the binary or test directly should be listed in the srcs.

To illustrate these rules, look at the following example.

cc_binary(
    name = "foo",
    srcs = [
        "foo.cc",
        "foo.h",
    ],
    deps = [":bar"],
)

cc_library(
    name = "bar",
    srcs = [
        "bar.cc",
        "bar-impl.h",
    ],
    hdrs = ["bar.h"],
    deps = [":baz"],
)

cc_library(
    name = "baz",
    srcs = [
        "baz.cc",
        "baz-impl.h",
    ],
    hdrs = ["baz.h"],
)

The allowed direct inclusions in this example are listed in the table below. For example foo.cc is allowed to directly include foo.h and bar.h, but not baz.h.

Including file	Allowed inclusions
foo.h	bar.h
foo.cc	foo.h bar.h
bar.h	bar-impl.h baz.h
bar-impl.h	bar.h baz.h
bar.cc	bar.h bar-impl.h baz.h
baz.h	baz-impl.h
baz-impl.h	baz.h
baz.cc	baz.h baz-impl.h

The inclusion checking rules only apply to direct inclusions. In the example above foo.cc is allowed to include bar.h, which may include baz.h, which in turn is allowed to include baz-impl.h. Technically, the compilation of a .cc file may transitively include any header file in the hdrs or srcs in any cc_library in the transitive deps closure. In this case the compiler may read baz.h and baz-impl.h when compiling foo.cc, but foo.cc must not contain #include "baz.h". For that to be allowed, baz must be added to the deps of foo.

Bazel depends on toolchain support to enforce the inclusion checking rules. The layering_check feature has to be supported by the toolchain and requested explicitly, for example via the --features=layering_check command-line flag or the features parameter of the package function. The toolchains provided by Bazel only support this feature with clang on Unix and macOS.

Arguments

Attributes
`name`	Name; required A unique name for this target.
`deps`	List of labels; default is `[]` The list of other libraries to be linked in to the binary target. These can be `cc_library` or `objc_library` targets.
`srcs`	List of labels; default is `[]` The list of C and C++ files that are processed to create the target. These are C/C++ source and header files, either non-generated (normal source code) or generated. All `.cc`, `.c`, and `.cpp` files will be compiled. These might be generated files: if a named file is in the `outs` of some other rule, this rule will automatically depend on that other rule. A `.h` file will not be compiled, but will be available for inclusion by sources in this rule. Both `.cc` and `.h` files can directly include headers listed in these `srcs` or in the `hdrs` of any rule listed in the `deps` argument. All `#include`d files must be mentioned in the `srcs` attribute of this rule, or in the `hdrs` attribute of referenced `cc_library()`s. The recommended style is for headers associated with a library to be listed in that library's `hdrs` attribute, and any remaining headers associated with this rule's sources to be listed in `srcs`. See "Header inclusion checking" for a more detailed description. If a rule's name is in the `srcs`, then this rule automatically depends on that one. If the named rule's `outs` are C or C++ source files, they are compiled into this rule; if they are library files, they are linked in. Permitted `srcs` file types: C and C++ source files: `.c`, `.cc`, `.cpp`, `.cxx`, `.c++`, `.C` C and C++ header files: `.h`, `.hh`, `.hpp`, `.hxx`, `.inc`, `.inl`, `.H` Assembler with C preprocessor: `.S` Archive: `.a`, `.pic.a` "Always link" library: `.lo`, `.pic.lo` Shared library, versioned or unversioned: `.so`, `.so.version` Object file: `.o`, `.pic.o` ...and any rules that produce those files. Different extensions denote different programming languages in accordance with gcc convention.
`hdrs`	List of labels; default is `[]` The list of header files published by this library to be directly included by sources in dependent rules. This is the strongly preferred location for declaring header files that describe the interface for the library. These headers will be made available for inclusion by sources in this rule or in dependent rules. Headers not meant to be included by a client of this library should be listed in the `srcs` attribute instead, even if they are included by a published header. See "Header inclusion checking" for a more detailed description.
`additional_compiler_inputs`	List of labels; default is `[]` Any additional files you might want to pass to the compiler command line, such as sanitizer ignorelists, for example. Files specified here can then be used in copts with the $(location) function.
`additional_linker_inputs`	List of labels; default is `[]` Pass these files to the C++ linker command. For example, compiled Windows .res files can be provided here to be embedded in the binary target.
`alwayslink`	Boolean; default is `False` If 1, any binary that depends (directly or indirectly) on this C++ library will link in all the object files for the files listed in `srcs`, even if some contain no symbols referenced by the binary. This is useful if your code isn't explicitly called by code in the binary, e.g., if your code registers to receive some callback provided by some service. If alwayslink doesn't work with VS 2017 on Windows, that is due to a known issue, please upgrade your VS 2017 to the latest version.
`copts`	List of strings; default is `[]` Add these options to the C++ compilation command. Subject to "Make variable" substitution and Bourne shell tokenization. Each string in this attribute is added in the given order to `COPTS` before compiling the binary target. The flags take effect only for compiling this target, not its dependencies, so be careful about header files included elsewhere. All paths should be relative to the workspace, not to the current package. If the package declares the feature `no_copts_tokenization`, Bourne shell tokenization applies only to strings that consist of a single "Make" variable.
`defines`	List of strings; default is `[]` List of defines to add to the compile line. Subject to "Make" variable substitution and Bourne shell tokenization. Each string, which must consist of a single Bourne shell token, is prepended with `-D` and added to the compile command line to this target, as well as to every rule that depends on it. Be very careful, since this may have far-reaching effects. When in doubt, add define values to `local_defines` instead.
`implementation_deps`	List of labels; default is `[]` The list of other libraries that the library target depends on. Unlike with `deps`, the headers and include paths of these libraries (and all their transitive deps) are only used for compilation of this library, and not libraries that depend on it. Libraries specified with `implementation_deps` are still linked in binary targets that depend on this library. For now usage is limited to cc_libraries and guarded by the flag `--experimental_cc_implementation_deps`.
`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.
`includes`	List of strings; default is `[]` List of include dirs to be added to the compile line. Subject to "Make variable" substitution. Each string is prepended with `-isystem` and added to `COPTS`. Unlike COPTS, these flags are added for this rule and every rule that depends on it. (Note: not the rules it depends upon!) Be very careful, since this may have far-reaching effects. When in doubt, add "-I" flags to COPTS instead. Headers must be added to srcs or hdrs, otherwise they will not be available to dependent rules when compilation is sandboxed (the default).
`linkopts`	List of strings; default is `[]` Add these flags to the C++ linker command. Subject to "Make" variable substitution, Bourne shell tokenization and label expansion. Each string in this attribute is added to `LINKOPTS` before linking the binary target. Each element of this list that does not start with `$` or `-` is assumed to be the label of a target in `deps`. The list of files generated by that target is appended to the linker options. An error is reported if the label is invalid, or is not declared in `deps`.
`linkstamp`	Label; default is `None` Simultaneously compiles and links the specified C++ source file into the final binary. This trickery is required to introduce timestamp information into binaries; if we compiled the source file to an object file in the usual way, the timestamp would be incorrect. A linkstamp compilation may not include any particular set of compiler flags and so should not depend on any particular header, compiler option, or other build variable. This option should only be needed in the `base` package.
`linkstatic`	Boolean; default is `False` For `cc_binary` and `cc_test`: link the binary in static mode. For `cc_library.linkstatic`: see below. By default this option is on for `cc_binary` and off for the rest. If enabled and this is a binary or test, this option tells the build tool to link in `.a`'s instead of `.so`'s for user libraries whenever possible. Some system libraries may still be linked dynamically, as are libraries for which there is no static library. So the resulting executable will still be dynamically linked, hence only mostly static. There are really three different ways to link an executable: STATIC with fully_static_link feature, in which everything is linked statically; e.g. "`gcc -static foo.o libbar.a libbaz.a -lm`". This mode is enabled by specifying `fully_static_link` in the `features` attribute. STATIC, in which all user libraries are linked statically (if a static version is available), but where system libraries (excluding C/C++ runtime libraries) are linked dynamically, e.g. "`gcc foo.o libfoo.a libbaz.a -lm`". This mode is enabled by specifying `linkstatic=True`. DYNAMIC, in which all libraries are linked dynamically (if a dynamic version is available), e.g. "`gcc foo.o libfoo.so libbaz.so -lm`". This mode is enabled by specifying `linkstatic=False`. The `linkstatic` attribute has a different meaning if used on a `cc_library()` rule. For a C++ library, `linkstatic=True` indicates that only static linking is allowed, so no `.so` will be produced. linkstatic=False does not prevent static libraries from being created. The attribute is meant to control the creation of dynamic libraries. If `linkstatic=False`, then the build tool will create symlinks to depended-upon shared libraries in the `*.runfiles` area.
`local_defines`	List of strings; default is `[]` List of defines to add to the compile line. Subject to "Make" variable substitution and Bourne shell tokenization. Each string, which must consist of a single Bourne shell token, is prepended with `-D` and added to the compile command line for this target, but not to its dependents.
`nocopts`	String; default is `""` Remove matching options from the C++ compilation command. Subject to "Make" variable substitution. The value of this attribute is interpreted as a regular expression. Any preexisting `COPTS` that match this regular expression (including values explicitly specified in the rule's copts attribute) will be removed from `COPTS` for purposes of compiling this rule. This attribute should rarely be needed.
`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.
`textual_hdrs`	List of labels; default is `[]` The list of header files published by this library to be textually included by sources in dependent rules. This is the location for declaring header files that cannot be compiled on their own; that is, they always need to be textually included by other source files to build valid code.
`win_def_file`	Label; default is `None` The Windows DEF file to be passed to linker. This attribute should only be used when Windows is the target platform. It can be used to export symbols during linking a shared library.

cc_proto_library

View rule source

cc_proto_library(name, deps, data, compatible_with, deprecation, distribs, exec_compatible_with, exec_properties, features, licenses, restricted_to, tags, target_compatible_with, testonly, visibility)

cc_proto_library generates C++ code from .proto files.

deps must point to proto_library rules.

Example:

cc_library(
    name = "lib",
    deps = [":foo_cc_proto"],
)

cc_proto_library(
    name = "foo_cc_proto",
    deps = [":foo_proto"],
)

proto_library(
    name = "foo_proto",
)

Arguments

Attributes

name

Name; required

A unique name for this target.

deps

List of labels; default is []

The list of proto_library rules to generate C++ code for.

cc_shared_library

View rule source

cc_shared_library(name, deps, additional_linker_inputs, dynamic_deps, exports_filter, shared_lib_name, tags, user_link_flags, win_def_file)

It produces a shared library.

Example

cc_shared_library(
    name = "foo_shared",
    deps = [
        ":foo",
    ],
    dynamic_deps = [
        ":bar_shared",
    ],
    additional_linker_inputs = [
        ":foo.lds",
    ],
    user_link_flags = [
        "-Wl,--version-script=$(location :foo.lds)",
    ],
)
cc_library(
    name = "foo",
    srcs = ["foo.cc"],
    hdrs = ["foo.h"],
    deps = [
        ":bar",
        ":baz",
    ],
)
cc_shared_library(
    name = "bar_shared",
    shared_lib_name = "bar.so",
    deps = [":bar"],
)
cc_library(
    name = "bar",
    srcs = ["bar.cc"],
    hdrs = ["bar.h"],
)
cc_library(
    name = "baz",
    srcs = ["baz.cc"],
    hdrs = ["baz.h"],
)

In the example foo_shared statically links foo and baz, the latter being a transitive dependency. It doesn't link bar because it is already provided dynamically by the dynamic_dep bar_shared.

foo_shared uses a linker script *.lds file to control which symbols should be exported. The cc_shared_library rule logic does not control which symbols get exported, it only uses what is assumed to be exported to give errors during analysis phase if two shared libraries export the same targets.

Every direct dependency of cc_shared_library is assumed to be exported. Therefore, Bazel assumes during analysis that foo is being exported by foo_shared. baz is not assumed to be exported by foo_shared. Every target matched by the exports_filter is also assumed to be exported.

Every single cc_library in the example should appear at most in one cc_shared_library. If we wanted to link baz also into bar_shared we would need to add tags = ["LINKABLE_MORE_THAN_ONCE"] to baz.

Due to the shared_lib_name attribute, the file produced by bar_shared will have the name bar.so as opposed to the name libbar.so that it would have by default on Linux.

Errors

`Two shared libraries in dependencies export the same symbols.`

This will happen whenever you are creating a target with two different cc_shared_library dependencies that export the same target. To fix this you need to stop the libraries from being exported in one of the cc_shared_library dependencies.

`Two shared libraries in dependencies link the same library statically`

This will happen whenever you are creating a new cc_shared_library with two different cc_shared_library dependencies that link the same target statically. Similar to the error with exports.

One way to fix this is to stop linking the library into one of the cc_shared_library dependencies. At the same time, the one that still links it needs to export the library so that the one not linking it keeps visibility to the symbols. Another way is to pull out a third library that exports the target. A third way is to tag the culprit cc_library with LINKABLE_MORE_THAN_ONCE but this fix should be rare and you should absolutely make sure that the cc_library is indeed safe to link more than once.

'//foo:foo' is already linked statically in '//bar:bar' but not exported`

This means that a library in the transitive closure of your deps is reachable without going through one of the cc_shared_library dependencies but is already linked into a different cc_shared_library in dynamic_deps and is not exported.

The solution is to export it from the cc_shared_library dependency or pull out a third cc_shared_library that exports it.

`Do not place libraries which only contain a precompiled dynamic library in deps.`

If you have a precompiled dynamic library, this doesn't need to and cannot be linked statically into the current cc_shared_library target that you are currently creating. Therefore, it doesn't belong in deps of the cc_shared_library. If this precompiled dynamic library is a dependency of one of your cc_libraries, then the cc_library needs to depend on it directly.

`Trying to export a library already exported by a different shared library`

You will see this error if on the current rule you are claiming to export a target that is already being exported by one of your dynamic dependencies.

To fix this, remove the target from deps and just rely on it from the dynamic dependency or make sure that the exports_filter doesn't catch this target.

Arguments

Attributes
`name`	Name; required A unique name for this target.
`deps`	List of labels; default is `[]` Top level libraries that will unconditionally be statically linked into the shared library after being whole-archived. Any transitive library dependency of these direct deps will be linked into this shared library as long as they have not already been linked by a `cc_shared_library` in `dynamic_deps`. During analysis, the rule implementation will consider any target listed in `deps` as being exported by the shared library in order to give errors when multiple `cc_shared_libraries` export the same targets. The rule implementation does not take care of informing the linker about which symbols should be exported by the shared object. The user should take care of this via linker scripts or visibility declarations in the source code. The implementation will also trigger errors whenever the same library is linked statically into more than one `cc_shared_library`. This can be avoided by adding `"LINKABLE_MORE_THAN_ONCE"` to the `cc_library.tags` or by listing the `cc_library` as an export of one of the shared libraries so that one can be made a `dynamic_dep` of the other.
`additional_linker_inputs`	List of labels; default is `[]` Any additional files that you may want to pass to the linker, for example, linker scripts. You have to separately pass any linker flags that the linker needs in order to be aware of this file. You can do so via the `user_link_flags` attribute.
`dynamic_deps`	List of labels; default is `[]` These are other `cc_shared_library` dependencies the current target depends on. The `cc_shared_library` implementation will use the list of `dynamic_deps` (transitively, i.e. also the `dynamic_deps` of the current target's `dynamic_deps`) to decide which `cc_libraries` in the transitive `deps` should not be linked in because they are already provided by a different `cc_shared_library`.
`exports_filter`	List of strings; default is `[]` This attribute contains a list of targets that are claimed to be exported by the current shared library. Any target `deps` is already understood to be exported by the shared library. This attribute should be used to list any targets that are exported by the shared library but are transitive dependencies of `deps`. Note that this attribute is not actually adding a dependency edge to those targets, the dependency edge should instead be created by `deps`.The entries in this attribute are just strings. Keep in mind that when placing a target in this attribute, this is considered a claim that the shared library exports the symbols from that target. The `cc_shared_library` logic doesn't actually handle telling the linker which symbols should be exported. The following syntax is allowed: `//foo:__package__` to account for any target in foo/BUILD `//foo:__subpackages__` to account for any target in foo/BUILD or any other package below foo/ like foo/bar/BUILD
`shared_lib_name`	String; default is `""` By default cc_shared_library will use a name for the shared library output file based on the target's name and the platform. This includes an extension and sometimes a prefix. Sometimes you may not want the default name, for example, when loading C++ shared libraries for Python the default lib* prefix is often not desired, in which case you can use this attribute to choose a custom name.
`user_link_flags`	List of strings; default is `[]` Any additional flags that you may want to pass to the linker. For example, to make the linker aware of a linker script passed via additional_linker_inputs you can use the following: cc_shared_library( name = "foo_shared", additional_linker_inputs = select({ "//src/conditions:linux": [ ":foo.lds", ":additional_script.txt", ], "//conditions:default": []}), user_link_flags = select({ "//src/conditions:linux": [ "-Wl,-rpath,kittens", "-Wl,--version-script=$(location :foo.lds)", "-Wl,--script=$(location :additional_script.txt)", ], "//conditions:default": []}), ... )
`win_def_file`	Label; default is `None` The Windows DEF file to be passed to linker. This attribute should only be used when Windows is the target platform. It can be used to export symbols during linking a shared library.

fdo_prefetch_hints

View rule source

fdo_prefetch_hints(name, compatible_with, deprecation, distribs, features, licenses, profile, restricted_to, tags, target_compatible_with, testonly, visibility)

Represents an FDO prefetch hints profile that is either in the workspace or at a specified absolute path. Examples:

fdo_prefetch_hints(
    name = "hints",
    profile = "//path/to/hints:profile.afdo",
)

fdo_profile(
  name = "hints_abs",
  absolute_path_profile = "/absolute/path/profile.afdo",
)

Arguments

Attributes

name

Name; required

A unique name for this target.

profile

Label; default is None

Label of the hints profile. The hints file has the .afdo extension The label can also point to an fdo_absolute_path_profile rule.

fdo_profile

View rule source

fdo_profile(name, absolute_path_profile, compatible_with, deprecation, distribs, features, licenses, profile, proto_profile, restricted_to, tags, target_compatible_with, testonly, visibility)

Represents an FDO profile that is either in the workspace or at a specified absolute path. Examples:

fdo_profile(
    name = "fdo",
    profile = "//path/to/fdo:profile.zip",
)

fdo_profile(
  name = "fdo_abs",
  absolute_path_profile = "/absolute/path/profile.zip",
)

Arguments

Attributes
`name`	Name; required A unique name for this target.
`absolute_path_profile`	String; default is `""` Absolute path to the FDO profile. The FDO file can have one of the following extensions: .profraw for unindexed LLVM profile, .profdata for indexed LLVM profile, .zip that holds an LLVM profraw profile, or .afdo for AutoFDO profile.
`profile`	Label; default is `None` Label of the FDO profile or a rule which generates it. The FDO file can have one of the following extensions: .profraw for unindexed LLVM profile, .profdata for indexed LLVM profile, .zip that holds an LLVM profraw profile, .afdo for AutoFDO profile, .xfdo for XBinary profile. The label can also point to an fdo_absolute_path_profile rule.
`proto_profile`	Label; default is `None` Label of the protobuf profile.

memprof_profile

View rule source

memprof_profile(name, absolute_path_profile, compatible_with, deprecation, distribs, features, licenses, profile, restricted_to, tags, target_compatible_with, testonly, visibility)

Represents a MEMPROF profile that is either in the workspace or at a specified absolute path. Examples:

memprof_profile(
    name = "memprof",
    profile = "//path/to/memprof:profile.afdo",
)

memprof_profile(
  name = "memprof_abs",
  absolute_path_profile = "/absolute/path/profile.afdo",
)

Arguments

Attributes

name

Name; required

A unique name for this target.

absolute_path_profile

String; default is ""

Absolute path to the MEMPROF profile. The file may only have a .profdata or .zip extension (where the zipfile must contain a memprof.profdata file).

profile

Label; default is None

Label of the MEMPROF profile. The profile is expected to have either a .profdata extension (for an indexed/symbolized memprof profile), or a .zip extension for a zipfile containing a memprof.profdata file. The label can also point to an fdo_absolute_path_profile rule.

propeller_optimize

View rule source

propeller_optimize(name, compatible_with, deprecation, distribs, features, ld_profile, licenses, restricted_to, tags, target_compatible_with, testonly, visibility)

Represents a Propeller optimization profile in the workspace. Example:

propeller_optimize(
    name = "layout",
    cc_profile = "//path:cc_profile.txt",
    ld_profile = "//path:ld_profile.txt"
)

propeller_optimize(
    name = "layout_absolute",
    absolute_cc_profile = "/absolute/cc_profile.txt",
    absolute_ld_profile = "/absolute/ld_profile.txt"
)

Arguments

Attributes

name

Name; required

A unique name for this target.

ld_profile

Label; default is None

Label of the profile passed to the link action. This file has the .txt extension.

cc_test

View rule source

cc_test(name, deps, srcs, data, additional_linker_inputs, args, compatible_with, copts, defines, deprecation, distribs, env, env_inherit, exec_compatible_with, exec_properties, features, flaky, includes, licenses, link_extra_lib, linkopts, linkstatic, local, local_defines, malloc, nocopts, restricted_to, shard_count, size, stamp, tags, target_compatible_with, testonly, timeout, toolchains, visibility, win_def_file)

Arguments

Attributes
`name`	Name; required A unique name for this target.
`deps`	List of labels; default is `[]` The list of other libraries to be linked in to the binary target. These can be `cc_library` or `objc_library` targets.
`srcs`	List of labels; default is `[]` The list of C and C++ files that are processed to create the target. These are C/C++ source and header files, either non-generated (normal source code) or generated. All `.cc`, `.c`, and `.cpp` files will be compiled. These might be generated files: if a named file is in the `outs` of some other rule, this rule will automatically depend on that other rule. A `.h` file will not be compiled, but will be available for inclusion by sources in this rule. Both `.cc` and `.h` files can directly include headers listed in these `srcs` or in the `hdrs` of any rule listed in the `deps` argument. All `#include`d files must be mentioned in the `srcs` attribute of this rule, or in the `hdrs` attribute of referenced `cc_library()`s. The recommended style is for headers associated with a library to be listed in that library's `hdrs` attribute, and any remaining headers associated with this rule's sources to be listed in `srcs`. See "Header inclusion checking" for a more detailed description. If a rule's name is in the `srcs`, then this rule automatically depends on that one. If the named rule's `outs` are C or C++ source files, they are compiled into this rule; if they are library files, they are linked in. Permitted `srcs` file types: C and C++ source files: `.c`, `.cc`, `.cpp`, `.cxx`, `.c++`, `.C` C and C++ header files: `.h`, `.hh`, `.hpp`, `.hxx`, `.inc`, `.inl`, `.H` Assembler with C preprocessor: `.S` Archive: `.a`, `.pic.a` "Always link" library: `.lo`, `.pic.lo` Shared library, versioned or unversioned: `.so`, `.so.version` Object file: `.o`, `.pic.o` ...and any rules that produce those files. Different extensions denote different programming languages in accordance with gcc convention.
`additional_linker_inputs`	List of labels; default is `[]` Pass these files to the C++ linker command. For example, compiled Windows .res files can be provided here to be embedded in the binary target.
`copts`	List of strings; default is `[]` Add these options to the C++ compilation command. Subject to "Make variable" substitution and Bourne shell tokenization. Each string in this attribute is added in the given order to `COPTS` before compiling the binary target. The flags take effect only for compiling this target, not its dependencies, so be careful about header files included elsewhere. All paths should be relative to the workspace, not to the current package. If the package declares the feature `no_copts_tokenization`, Bourne shell tokenization applies only to strings that consist of a single "Make" variable.
`defines`	List of strings; default is `[]` List of defines to add to the compile line. Subject to "Make" variable substitution and Bourne shell tokenization. Each string, which must consist of a single Bourne shell token, is prepended with `-D` and added to the compile command line to this target, as well as to every rule that depends on it. Be very careful, since this may have far-reaching effects. When in doubt, add define values to `local_defines` instead.
`includes`	List of strings; default is `[]` List of include dirs to be added to the compile line. Subject to "Make variable" substitution. Each string is prepended with `-isystem` and added to `COPTS`. Unlike COPTS, these flags are added for this rule and every rule that depends on it. (Note: not the rules it depends upon!) Be very careful, since this may have far-reaching effects. When in doubt, add "-I" flags to COPTS instead. Headers must be added to srcs or hdrs, otherwise they will not be available to dependent rules when compilation is sandboxed (the default).
`link_extra_lib`	Label; default is `"@bazel_tools//tools/cpp:link_extra_lib"` Control linking of extra libraries. By default, C++ binaries are linked against `//tools/cpp:link_extra_lib`, which by default depends on the label flag `//tools/cpp:link_extra_libs`. Without setting the flag, this library is empty by default. Setting the label flag allows linking optional dependencies, such as overrides for weak symbols, interceptors for shared library functions, or special runtime libraries (for malloc replacements, prefer `malloc` or `--custom_malloc`). Setting this attribute to `None` disables this behaviour.
`linkopts`	List of strings; default is `[]` Add these flags to the C++ linker command. Subject to "Make" variable substitution, Bourne shell tokenization and label expansion. Each string in this attribute is added to `LINKOPTS` before linking the binary target. Each element of this list that does not start with `$` or `-` is assumed to be the label of a target in `deps`. The list of files generated by that target is appended to the linker options. An error is reported if the label is invalid, or is not declared in `deps`.
`linkstatic`	Boolean; default is `False` For `cc_binary` and `cc_test`: link the binary in static mode. For `cc_library.linkstatic`: see below. By default this option is on for `cc_binary` and off for the rest. If enabled and this is a binary or test, this option tells the build tool to link in `.a`'s instead of `.so`'s for user libraries whenever possible. Some system libraries may still be linked dynamically, as are libraries for which there is no static library. So the resulting executable will still be dynamically linked, hence only mostly static. There are really three different ways to link an executable: STATIC with fully_static_link feature, in which everything is linked statically; e.g. "`gcc -static foo.o libbar.a libbaz.a -lm`". This mode is enabled by specifying `fully_static_link` in the `features` attribute. STATIC, in which all user libraries are linked statically (if a static version is available), but where system libraries (excluding C/C++ runtime libraries) are linked dynamically, e.g. "`gcc foo.o libfoo.a libbaz.a -lm`". This mode is enabled by specifying `linkstatic=True`. DYNAMIC, in which all libraries are linked dynamically (if a dynamic version is available), e.g. "`gcc foo.o libfoo.so libbaz.so -lm`". This mode is enabled by specifying `linkstatic=False`. The `linkstatic` attribute has a different meaning if used on a `cc_library()` rule. For a C++ library, `linkstatic=True` indicates that only static linking is allowed, so no `.so` will be produced. linkstatic=False does not prevent static libraries from being created. The attribute is meant to control the creation of dynamic libraries. If `linkstatic=False`, then the build tool will create symlinks to depended-upon shared libraries in the `*.runfiles` area.
`local_defines`	List of strings; default is `[]` List of defines to add to the compile line. Subject to "Make" variable substitution and Bourne shell tokenization. Each string, which must consist of a single Bourne shell token, is prepended with `-D` and added to the compile command line for this target, but not to its dependents.
`malloc`	Label; default is `"@bazel_tools//tools/cpp:malloc"` Override the default dependency on malloc. By default, C++ binaries are linked against `//tools/cpp:malloc`, which is an empty library so the binary ends up using libc malloc. This label must refer to a `cc_library`. If compilation is for a non-C++ rule, this option has no effect. The value of this attribute is ignored if `linkshared=True` is specified.
`nocopts`	String; default is `""` Remove matching options from the C++ compilation command. Subject to "Make" variable substitution. The value of this attribute is interpreted as a regular expression. Any preexisting `COPTS` that match this regular expression (including values explicitly specified in the rule's copts attribute) will be removed from `COPTS` for purposes of compiling this rule. This attribute should rarely be needed.
`stamp`	Integer; default is `0` Whether to encode build information into the binary. Possible values: `stamp = 1`: Always stamp the build information into the binary, even in `--nostamp` builds. This setting should be avoided, since it potentially kills remote caching for the binary and any downstream actions that depend on it. `stamp = 0`: Always replace build information by constant values. This gives good build result caching. `stamp = -1`: Embedding of build information is controlled by the `--[no]stamp` flag. Stamped binaries are not rebuilt unless their dependencies change.
`win_def_file`	Label; default is `None` The Windows DEF file to be passed to linker. This attribute should only be used when Windows is the target platform. It can be used to export symbols during linking a shared library.

cc_toolchain

View rule source

cc_toolchain(name, all_files, ar_files, as_files, compatible_with, compiler_files, compiler_files_without_includes, coverage_files, deprecation, distribs, dwp_files, dynamic_runtime_lib, exec_transition_for_inputs, features, libc_top, licenses, linker_files, module_map, objcopy_files, restricted_to, static_runtime_lib, strip_files, supports_header_parsing, supports_param_files, tags, target_compatible_with, testonly, toolchain_config, toolchain_identifier, visibility)

Represents a C++ toolchain.

This rule is responsible for:

Collecting all artifacts needed for C++ actions to run. This is done by attributes such as all_files, compiler_files, linker_files, or other attributes ending with _files). These are most commonly filegroups globbing all required files.
Generating correct command lines for C++ actions. This is done using CcToolchainConfigInfo provider (details below).

Use toolchain_config attribute to configure the C++ toolchain. See also this page for elaborate C++ toolchain configuration and toolchain selection documentation.

Use tags = ["manual"] in order to prevent toolchains from being built and configured unnecessarily when invoking bazel build //...

Arguments

Attributes
`name`	Name; required A unique name for this target.
`all_files`	Label; required Collection of all cc_toolchain artifacts. These artifacts will be added as inputs to all rules_cc related actions (with the exception of actions that are using more precise sets of artifacts from attributes below). Bazel assumes that `all_files` is a superset of all other artifact-providing attributes (e.g. linkstamp compilation needs both compile and link files, so it takes `all_files`). This is what `cc_toolchain.files` contains, and this is used by all Starlark rules using C++ toolchain.
`ar_files`	Label; default is `None` Collection of all cc_toolchain artifacts required for archiving actions.
`as_files`	Label; default is `None` Collection of all cc_toolchain artifacts required for assembly actions.
`compiler_files`	Label; required Collection of all cc_toolchain artifacts required for compile actions.
`compiler_files_without_includes`	Label; default is `None` Collection of all cc_toolchain artifacts required for compile actions in case when input discovery is supported (currently Google-only).
`coverage_files`	Label; default is `None` Collection of all cc_toolchain artifacts required for coverage actions. If not specified, all_files are used.
`dwp_files`	Label; required Collection of all cc_toolchain artifacts required for dwp actions.
`dynamic_runtime_lib`	Label; default is `None` Dynamic library artifact for the C++ runtime library (e.g. libstdc++.so). This will be used when 'static_link_cpp_runtimes' feature is enabled, and we're linking dependencies dynamically.
`exec_transition_for_inputs`	Boolean; default is `True` Set to True to build all file inputs to cc_toolchain for the exec platform, instead of having no transition (i.e. target platform by default).
`libc_top`	Label; default is `None` A collection of artifacts for libc passed as inputs to compile/linking actions.
`linker_files`	Label; required Collection of all cc_toolchain artifacts required for linking actions.
`module_map`	Label; default is `None` Module map artifact to be used for modular builds.
`objcopy_files`	Label; required Collection of all cc_toolchain artifacts required for objcopy actions.
`static_runtime_lib`	Label; default is `None` Static library artifact for the C++ runtime library (e.g. libstdc++.a). This will be used when 'static_link_cpp_runtimes' feature is enabled, and we're linking dependencies statically.
`strip_files`	Label; required Collection of all cc_toolchain artifacts required for strip actions.
`supports_header_parsing`	Boolean; default is `False` Set to True when cc_toolchain supports header parsing actions.
`supports_param_files`	Boolean; default is `True` Set to True when cc_toolchain supports using param files for linking actions.
`toolchain_config`	Label; required The label of the rule providing `cc_toolchain_config_info`.
`toolchain_identifier`	String; nonconfigurable; default is `""` The identifier used to match this cc_toolchain with the corresponding crosstool_config.toolchain. Until issue #5380 is fixed this is the recommended way of associating `cc_toolchain` with `CROSSTOOL.toolchain`. It will be replaced by the `toolchain_config` attribute (#5380).

cc_toolchain_suite

View rule source

cc_toolchain_suite(name, compatible_with, deprecation, distribs, features, licenses, restricted_to, tags, target_compatible_with, testonly, toolchains, visibility)

Represents a collections of C++ toolchains.

This rule is responsible for:

Collecting all relevant C++ toolchains.
Selecting one toolchain depending on --cpu and --compiler options passed to Bazel.

See also this page for elaborate C++ toolchain configuration and toolchain selection documentation.

Arguments

Attributes

name

Name; required

A unique name for this target.

toolchains

Dictionary mapping strings to labels; nonconfigurable; required

A map from "<cpu>" or "<cpu>|<compiler>" strings to a cc_toolchain label. "<cpu>" will be used when only --cpu is passed to Bazel, and "<cpu>|<compiler>" will be used when both --cpu and --compiler are passed to Bazel. Example:

          cc_toolchain_suite(
            name = "toolchain",
            toolchains = {
              "piii|gcc": ":my_cc_toolchain_for_piii_using_gcc",
              "piii": ":my_cc_toolchain_for_piii_using_default_compiler",
            },
          )