build/unification/zx_library.gni - fuchsia - Git at Google

 # Copyright 2020 The Fuchsia Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

 import("//build/cpp/sdk_shared_library.gni")
 import("//build/cpp/sdk_source_set.gni")
 import("//build/cpp/sdk_static_library.gni")
 import("//build/unification/global_variables.gni")

 # Build a zircon-specific library, possibly in several ways.
 #
 # This template should be used by Zircon build rules exclusively, and follows
 # most of the conventions of the Zircon build `library()` template, which
 # differ significantly from those of `library()` in the Fuchsia build.
 #
 # IMPORTANT NOTE: Due to historical reasons, its behaviour is very different,
 # depending on the value of the `is_kernel` global variable.
 #
 # * If `is_kernel` is true, which means when building part of the kernel:
 #   The template will assert if the `kernel` argument is not set to true.
 #   It will create a source_set() if building part of the kernel, or
 #   a static_library() for any other Zircon artefact. The values of `sdk`,
 #   `sdk_publishable` and `sdk_headers` will be ignored entirely.
 #
 #   This will also create a :headers sub-target, a group used to give access
 #   to the library's include directory from any dependent. Note that this
 #   does *not* make the library's headers, listed in `sdk_headers` public.
 #
 #   This behaviour is needed to replicate the Zircon build's behaviour when
 #   compiling Zircon artefacts.
 #
 # * If `is`_kernel` is false, which means that the library is built either as a
 #   Fuchsia user binary or a host binary, then the `kernel` parameter is
 #   ignored, and `sdk` must be set to determine the shape of the library,
 #   as well as `sdk_headers to list the library's public headers, relative to
 #   its `include` sub-directory.
 #
 #   If `sdk_publishable` is true, the library will be part of the Fuchsia SDK.
 #
 #   Any :headers sub-targets that appear in public_deps will be rewritten into
 #   a dependency to the library itself, e.g.:
 #
 #     public_deps = [ "//zircon/system/ulib/foo:headers" ]
 #
 #   will be replaced by:
 #
 #     public_deps = [ "//zircon/system/ulib/foo" ]
 #
 #   Because the Fuchsia build doesn't support :headers sub-targets in
 #   non-kernel libraries for several technical reasons.
 #
 #   Similarly, any deps or public_deps entry to
 #   //zircon/system/ulib/zircon will be replaced by the proper dependency
 #   required to access Zircon headers and, for Fuchsia user binaries, the
 #   link-time VDSO. This feature will be removed once the VDSO is built
 #   with the Fuchsia build.
 #
 # Parameters
 #
 #   kernel
 #     Optional: True if this library can be used in the kernel.
 #     Type: bool
 #     Default: false
 #
 #   sdk
 #     Optional: A value that indicates whether to build this library as a
 #     source set, static library or shared library with the Fuchsia build.
 #     This is required, except if the global `is_kernel` is true. Note that
 #     this name is confusing for historical reasons, because using
 #     this parameter does not make this library exported to the Fuchsia SDK
 #     (see `sdk_publishable` below for this).
 #     Type: "static" or "shared" or "source"
 #
 #   sdk_publishable
 #     Optional: Indicates that this library can be added to the Fuchsia SDK.
 #     Type: bool
 #     Default: false
 #
 #   sdk_headers
 #     Optional: Required, except if the global `is_kernel` is true.
 #     This must list all the public header files in the library's `include/`
 #     directory; names should be relative to `include/`.
 #     Type: list(string)
 #
 #   sdk_name
 #     Optional: Name under which the library is published. This can be used
 #     when $target_name is already used by another target in the Fuchsia build.
 #     Type: string
 #     Default: target_name
 #
 #   See source_set() for other parameters.
 #
 # The following parameters are ignored by this implementation. They are here
 # to support zx_library() calls that are shared by BUILD.zircon.gn and BUILD.gn
 # file. Support for these may be removed after build unification completes.
 #
 #   host
 #     Optional: Was set to true if this library can be used in
 #     host-side code, e.g. to be a dependency of a host_tool().
 #     Type: bool
 #     Default: false
 #
 #   static
 #     Optional: True if this library can be statically linked in user code.
 #     Type: bool
 #     Default: !$kernel
 #
 #   shared
 #     Optional: True if this library can be made a shared library for user code.
 #     Type: bool
 #     Default: false
 #
 #   sdk_migrated
 #     Optional: Indicates that this library is built directly by the Fuchsia
 #     build, and no longer needs to be exported as a legacy target. This is
 #     used to ease build unification, and will disappear once it is completed.
 #     Type: bool
 #     Default: false
 #
 template("zx_library") {
   template_params = [
     "host",
     "kernel",
     "sdk",
     "sdk_headers",
     "sdk_publishable",
     "shared",
     "static",
   ]

   # `sdk_migrated` is only used by the Zircon build system.
   not_needed(invoker, [ "sdk_migrated" ])

   if (is_kernel) {
     _library_name = target_name

     assert(
         defined(invoker.kernel) && invoker.kernel,
         "This zx_library() cannot be built with a Zircon-specific toolchain! " +
         "Consider adding `kernel = true` to its declaration.")

     if (toolchain.environment == "kernel") {
       # In the kernel proper, zx_library() is always a source_set().
       # Everything goes into the kernel and anything unused gets linker GC.
       kernel_library_target_type = "source_set"
     } else {
       kernel_library_target_type = "static_library"
     }

     target(kernel_library_target_type, _library_name) {
       if (kernel_library_target_type == "static_library") {
         complete_static_lib = true
       }
       forward_variables_from(invoker, "*", template_params)
       if (!defined(public_deps)) {
         public_deps = []
       }
       public_deps += [ ":headers" ]
     }

     # Simplifying assumption that prevents us from reproducing the extra logic
     # in the original Zircon build library() template definition.
     assert(
         get_label_info(":$_library_name", "name") ==
             get_path_info(get_label_info(":$_library_name", "dir"), "file"),
         "A zx_library() with 'kernel = true' should have the same name as its directory.")

     group("headers") {
       # Used to represent header dependencies.
       # Direct us of public_configs should be rare but is sometimes needed.
       forward_variables_from(invoker,
                              [
                                "public_configs",
                                "public_deps",
                                "testonly",
                                "visibility",
                              ])
       if (!defined(public_configs)) {
         public_configs = []
       }
       public_configs += [ ":headers.config" ]
     }

     config("headers.config") {
       include_dirs = [ "include" ]
     }
   } else {
     # The following parameters are just ignored, as in the GN build the shape of
     # a library is driven by the value of the "sdk" parameter.
     not_needed(invoker,
                [
                  "kernel",
                  "host",
                  "static",
                  "shared",
                ])

     assert(defined(invoker.sdk),
            "The `sdk` argument is needed to build a zx_library() with a Fuchsia or host toolchain")
     shape = invoker.sdk

     sdkable = defined(invoker.sdk_publishable) && invoker.sdk_publishable

     extra_target_args = {
     }
     if (shape == "source") {
       if (sdkable) {
         target_type = "sdk_source_set"
         extra_target_args = {
           category = "partner"
           api = "//sdk/lib/$target_name/$target_name.api"
           sdk_name = target_name
           build_as_static = true
         }
       } else {
         target_type = "static_library"
       }
     } else if (shape == "static") {
       if (sdkable) {
         target_type = "sdk_static_library"
         extra_target_args = {
           category = "partner"
           api = "//sdk/lib/$target_name/$target_name.api"
           sdk_name = target_name
           libcxx_linkage = "static"
         }
       } else {
         target_type = "static_library"
       }
     } else if (shape == "shared") {
       if (sdkable) {
         target_type = "sdk_shared_library"
         extra_target_args = {
           category = "partner"
           api = "//sdk/lib/$target_name/$target_name.api"
           symbols_api = "//sdk/lib/$target_name/$target_name.symbols.api"
           sdk_name = target_name
           libcxx_linkage = "static"
         }
       } else {
         target_type = "shared_library"
       }
     } else {
       assert(false, "Unknown library type: $shape")
     }

     main_target_name = target_name
     if (defined(invoker.sdk_name)) {
       main_target_name = invoker.sdk_name
     }
     config_target_name = "$target_name.config"

     config(config_target_name) {
       include_dirs = [ "include" ]
     }

     # IMPORTANT: Rewrite header dependencies in public_deps
     #
     # For each zx_library(), the Zircon build used to produce a 'headers'
     # group that adds a 'headers.config' public config. This is done to allow
     # other targets to depend on the library's headers, but not the library
     # itself.
     #
     # In practice, this means it is common for targets to list these headers
     # groups in their public_deps, as in:
     #
     #    public_deps = [ "$zx/system/ulib/fit:headers" ]
     #
     # However, these groups do not mix well with the Fuchsia build, and
     # especially with sdk_source_set() or sdk_static_library().
     #
     # To work around this, rewrite the headers public dependencies into
     # regular dependencies into the libraries themselves.
     #
     lib_deps = []
     if (defined(invoker.deps)) {
       lib_deps = invoker.deps
     }
     lib_public_deps = []
     if (defined(invoker.public_deps)) {
       foreach(dep, invoker.public_deps) {
         if (get_label_info(dep, "name") == "headers") {
           # Format //zircon/.../foo:headers  -> //zircon/.../foo
           dep = get_label_info(dep, "dir")
         } else if (get_path_info(get_label_info(dep, "name"), "extension") ==
                    "headers") {
           # Format //zircon/.../foo:bar.headers -> //zircon/.../foo:bar
           dep = get_label_info(dep, "dir") + ":" +
                 get_path_info(get_label_info(dep, "name"), "name")
         }
         lib_public_deps += [ dep ]
       }
     }

     # Remove references to a libzircon dependency, as it is provided by the
     # sysroot in the present build.

     lib_libs = []
     if (defined(invoker.libs)) {
       lib_dirs = invoker.libs
     }

     if (lib_deps + [ "//zircon/system/ulib/zircon" ] -
         [ "//zircon/system/ulib/zircon" ] != lib_deps) {
       lib_deps -= [ "//zircon/system/ulib/zircon" ]
       if (is_fuchsia) {
         lib_libs += [ "zircon" ]
       } else {
         lib_public_deps += [
           "//zircon/public/lib/zircon-headers",
           "//zircon/system/public",
         ]
       }
     }
     if (lib_public_deps + [ "//zircon/system/ulib/zircon" ] -
         [ "//zircon/system/ulib/zircon" ] != lib_public_deps) {
       lib_public_deps -= [ "//zircon/system/ulib/zircon" ]
       if (is_fuchsia) {
         lib_libs += [ "zircon" ]
       } else {
         lib_public_deps += [
           "//zircon/public/lib/zircon-headers",
           "//zircon/system/public",
         ]
       }
     }

     target(target_type, main_target_name) {
       forward_variables_from(invoker,
                              "*",
                              template_params + [
                                    "deps",
                                    "libs",
                                    "public_deps",
                                  ])

       deps = lib_deps
       libs = lib_libs
       public_deps = lib_public_deps

       forward_variables_from(extra_target_args, "*")

       if (defined(invoker.sdk_headers)) {
         public = []
         foreach(header, invoker.sdk_headers) {
           public += [ "include/$header" ]
         }
       }

       if (!defined(public_configs)) {
         public_configs = []
       }
       public_configs += [ ":$config_target_name" ]
     }
   }
 }

 set_defaults("zx_library") {
   configs = default_common_binary_configs
 }
	# Copyright 2020 The Fuchsia Authors. All rights reserved.
	# Use of this source code is governed by a BSD-style license that can be
	# found in the LICENSE file.

	import("//build/cpp/sdk_shared_library.gni")
	import("//build/cpp/sdk_source_set.gni")
	import("//build/cpp/sdk_static_library.gni")
	import("//build/unification/global_variables.gni")

	# Build a zircon-specific library, possibly in several ways.
	#
	# This template should be used by Zircon build rules exclusively, and follows
	# most of the conventions of the Zircon build `library()` template, which
	# differ significantly from those of `library()` in the Fuchsia build.
	#
	# IMPORTANT NOTE: Due to historical reasons, its behaviour is very different,
	# depending on the value of the `is_kernel` global variable.
	#
	# * If `is_kernel` is true, which means when building part of the kernel:
	# The template will assert if the `kernel` argument is not set to true.
	# It will create a source_set() if building part of the kernel, or
	# a static_library() for any other Zircon artefact. The values of `sdk`,
	# `sdk_publishable` and `sdk_headers` will be ignored entirely.
	#
	# This will also create a :headers sub-target, a group used to give access
	# to the library's include directory from any dependent. Note that this
	# does not make the library's headers, listed in `sdk_headers` public.
	#
	# This behaviour is needed to replicate the Zircon build's behaviour when
	# compiling Zircon artefacts.
	#
	# * If `is`_kernel` is false, which means that the library is built either as a
	# Fuchsia user binary or a host binary, then the `kernel` parameter is
	# ignored, and `sdk` must be set to determine the shape of the library,
	# as well as `sdk_headers to list the library's public headers, relative to
	# its `include` sub-directory.
	#
	# If `sdk_publishable` is true, the library will be part of the Fuchsia SDK.
	#
	# Any :headers sub-targets that appear in public_deps will be rewritten into
	# a dependency to the library itself, e.g.:
	#
	# public_deps = [ "//zircon/system/ulib/foo:headers" ]
	#
	# will be replaced by:
	#
	# public_deps = [ "//zircon/system/ulib/foo" ]
	#
	# Because the Fuchsia build doesn't support :headers sub-targets in
	# non-kernel libraries for several technical reasons.
	#
	# Similarly, any deps or public_deps entry to
	# //zircon/system/ulib/zircon will be replaced by the proper dependency
	# required to access Zircon headers and, for Fuchsia user binaries, the
	# link-time VDSO. This feature will be removed once the VDSO is built
	# with the Fuchsia build.
	#
	# Parameters
	#
	# kernel
	# Optional: True if this library can be used in the kernel.
	# Type: bool
	# Default: false
	#
	# sdk
	# Optional: A value that indicates whether to build this library as a
	# source set, static library or shared library with the Fuchsia build.
	# This is required, except if the global `is_kernel` is true. Note that
	# this name is confusing for historical reasons, because using
	# this parameter does not make this library exported to the Fuchsia SDK
	# (see `sdk_publishable` below for this).
	# Type: "static" or "shared" or "source"
	#
	# sdk_publishable
	# Optional: Indicates that this library can be added to the Fuchsia SDK.
	# Type: bool
	# Default: false
	#
	# sdk_headers
	# Optional: Required, except if the global `is_kernel` is true.
	# This must list all the public header files in the library's `include/`
	# directory; names should be relative to `include/`.
	# Type: list(string)
	#
	# sdk_name
	# Optional: Name under which the library is published. This can be used
	# when $target_name is already used by another target in the Fuchsia build.
	# Type: string
	# Default: target_name
	#
	# See source_set() for other parameters.
	#
	# The following parameters are ignored by this implementation. They are here
	# to support zx_library() calls that are shared by BUILD.zircon.gn and BUILD.gn
	# file. Support for these may be removed after build unification completes.
	#
	# host
	# Optional: Was set to true if this library can be used in
	# host-side code, e.g. to be a dependency of a host_tool().
	# Type: bool
	# Default: false
	#
	# static
	# Optional: True if this library can be statically linked in user code.
	# Type: bool
	# Default: !$kernel
	#
	# shared
	# Optional: True if this library can be made a shared library for user code.
	# Type: bool
	# Default: false
	#
	# sdk_migrated
	# Optional: Indicates that this library is built directly by the Fuchsia
	# build, and no longer needs to be exported as a legacy target. This is
	# used to ease build unification, and will disappear once it is completed.
	# Type: bool
	# Default: false
	#
	template("zx_library") {
	template_params = [
	"host",
	"kernel",
	"sdk",
	"sdk_headers",
	"sdk_publishable",
	"shared",
	"static",
	]

	# `sdk_migrated` is only used by the Zircon build system.
	not_needed(invoker, [ "sdk_migrated" ])

	if (is_kernel) {
	_library_name = target_name

	assert(
	defined(invoker.kernel) && invoker.kernel,
	"This zx_library() cannot be built with a Zircon-specific toolchain! " +
	"Consider adding `kernel = true` to its declaration.")

	if (toolchain.environment == "kernel") {
	# In the kernel proper, zx_library() is always a source_set().
	# Everything goes into the kernel and anything unused gets linker GC.
	kernel_library_target_type = "source_set"
	} else {
	kernel_library_target_type = "static_library"
	}

	target(kernel_library_target_type, _library_name) {
	if (kernel_library_target_type == "static_library") {
	complete_static_lib = true
	}
	forward_variables_from(invoker, "*", template_params)
	if (!defined(public_deps)) {
	public_deps = []
	}
	public_deps += [ ":headers" ]
	}

	# Simplifying assumption that prevents us from reproducing the extra logic
	# in the original Zircon build library() template definition.
	assert(
	get_label_info(":$_library_name", "name") ==
	get_path_info(get_label_info(":$_library_name", "dir"), "file"),
	"A zx_library() with 'kernel = true' should have the same name as its directory.")

	group("headers") {
	# Used to represent header dependencies.
	# Direct us of public_configs should be rare but is sometimes needed.
	forward_variables_from(invoker,
	[
	"public_configs",
	"public_deps",
	"testonly",
	"visibility",
	])
	if (!defined(public_configs)) {
	public_configs = []
	}
	public_configs += [ ":headers.config" ]
	}

	config("headers.config") {
	include_dirs = [ "include" ]
	}
	} else {
	# The following parameters are just ignored, as in the GN build the shape of
	# a library is driven by the value of the "sdk" parameter.
	not_needed(invoker,
	[
	"kernel",
	"host",
	"static",
	"shared",
	])

	assert(defined(invoker.sdk),
	"The `sdk` argument is needed to build a zx_library() with a Fuchsia or host toolchain")
	shape = invoker.sdk

	sdkable = defined(invoker.sdk_publishable) && invoker.sdk_publishable

	extra_target_args = {
	}
	if (shape == "source") {
	if (sdkable) {
	target_type = "sdk_source_set"
	extra_target_args = {
	category = "partner"
	api = "//sdk/lib/$target_name/$target_name.api"
	sdk_name = target_name
	build_as_static = true
	}
	} else {
	target_type = "static_library"
	}
	} else if (shape == "static") {
	if (sdkable) {
	target_type = "sdk_static_library"
	extra_target_args = {
	category = "partner"
	api = "//sdk/lib/$target_name/$target_name.api"
	sdk_name = target_name
	libcxx_linkage = "static"
	}
	} else {
	target_type = "static_library"
	}
	} else if (shape == "shared") {
	if (sdkable) {
	target_type = "sdk_shared_library"
	extra_target_args = {
	category = "partner"
	api = "//sdk/lib/$target_name/$target_name.api"
	symbols_api = "//sdk/lib/$target_name/$target_name.symbols.api"
	sdk_name = target_name
	libcxx_linkage = "static"
	}
	} else {
	target_type = "shared_library"
	}
	} else {
	assert(false, "Unknown library type: $shape")
	}

	main_target_name = target_name
	if (defined(invoker.sdk_name)) {
	main_target_name = invoker.sdk_name
	}
	config_target_name = "$target_name.config"

	config(config_target_name) {
	include_dirs = [ "include" ]
	}

	# IMPORTANT: Rewrite header dependencies in public_deps
	#
	# For each zx_library(), the Zircon build used to produce a 'headers'
	# group that adds a 'headers.config' public config. This is done to allow
	# other targets to depend on the library's headers, but not the library
	# itself.
	#
	# In practice, this means it is common for targets to list these headers
	# groups in their public_deps, as in:
	#
	# public_deps = [ "$zx/system/ulib/fit:headers" ]
	#
	# However, these groups do not mix well with the Fuchsia build, and
	# especially with sdk_source_set() or sdk_static_library().
	#
	# To work around this, rewrite the headers public dependencies into
	# regular dependencies into the libraries themselves.
	#
	lib_deps = []
	if (defined(invoker.deps)) {
	lib_deps = invoker.deps
	}
	lib_public_deps = []
	if (defined(invoker.public_deps)) {
	foreach(dep, invoker.public_deps) {
	if (get_label_info(dep, "name") == "headers") {
	# Format //zircon/.../foo:headers -> //zircon/.../foo
	dep = get_label_info(dep, "dir")
	} else if (get_path_info(get_label_info(dep, "name"), "extension") ==
	"headers") {
	# Format //zircon/.../foo:bar.headers -> //zircon/.../foo:bar
	dep = get_label_info(dep, "dir") + ":" +
	get_path_info(get_label_info(dep, "name"), "name")
	}
	lib_public_deps += [ dep ]
	}
	}

	# Remove references to a libzircon dependency, as it is provided by the
	# sysroot in the present build.

	lib_libs = []
	if (defined(invoker.libs)) {
	lib_dirs = invoker.libs
	}

	if (lib_deps + [ "//zircon/system/ulib/zircon" ] -
	[ "//zircon/system/ulib/zircon" ] != lib_deps) {
	lib_deps -= [ "//zircon/system/ulib/zircon" ]
	if (is_fuchsia) {
	lib_libs += [ "zircon" ]
	} else {
	lib_public_deps += [
	"//zircon/public/lib/zircon-headers",
	"//zircon/system/public",
	]
	}
	}
	if (lib_public_deps + [ "//zircon/system/ulib/zircon" ] -
	[ "//zircon/system/ulib/zircon" ] != lib_public_deps) {
	lib_public_deps -= [ "//zircon/system/ulib/zircon" ]
	if (is_fuchsia) {
	lib_libs += [ "zircon" ]
	} else {
	lib_public_deps += [
	"//zircon/public/lib/zircon-headers",
	"//zircon/system/public",
	]
	}
	}

	target(target_type, main_target_name) {
	forward_variables_from(invoker,
	"*",
	template_params + [
	"deps",
	"libs",
	"public_deps",
	])

	deps = lib_deps
	libs = lib_libs
	public_deps = lib_public_deps

	forward_variables_from(extra_target_args, "*")

	if (defined(invoker.sdk_headers)) {
	public = []
	foreach(header, invoker.sdk_headers) {
	public += [ "include/$header" ]
	}
	}

	if (!defined(public_configs)) {
	public_configs = []
	}
	public_configs += [ ":$config_target_name" ]
	}
	}
	}

	set_defaults("zx_library") {
	configs = default_common_binary_configs
	}