diff --git a/docs/gen/build_arguments.md b/docs/gen/build_arguments.md
index 38e3cf38cd97441e5178f4b091988d141f82cd94..f38718431b6d6b0e8b22b614e4c10393c9d532e9 100644
--- a/docs/gen/build_arguments.md
+++ b/docs/gen/build_arguments.md
@@ -2,20 +2,22 @@
## All builds
-### universal_variants
+### host_cpu
-**Current value (from the default):**
-```
-[{
- configs = []
- name = "release"
- toolchain_args = {
- is_debug = false
-}
-}]
-```
+**Current value (from the default):** `"x64"`
-From //build/config/BUILDCONFIG.gn:423
+### magma_python_path
+
+**Current value (from the default):** `"/b/s/w/ir/k/third_party/mako"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:14
+
+### build_sdk_archives
+Whether to build SDK tarballs.
+
+**Current value (from the default):** `false`
+
+From //build/sdk/sdk.gni:13
### enable_frame_pointers
Controls whether the compiler emits full stack frames for function calls.
@@ -30,78 +32,46 @@ remove this option when the issues are addressed.
From //build/config/BUILD.gn:19
-### rust_lto
-Sets the default LTO type for rustc bulids.
-
-**Current value (from the default):** `"unset"`
-
-From //build/rust/config.gni:20
-
-### shell_enable_vulkan
-
-**Current value (from the default):** `false`
-
-From //third_party/flutter/shell/config.gni:6
-
-### target_sysroot
-The absolute path of the sysroot that is used with the target toolchain.
+### flutter_runtime_mode
+The runtime mode ("debug", "profile", "release", "dynamic_profile", or "dynamic_release")
-**Current value (from the default):** `""`
+**Current value (from the default):** `"debug"`
-From //build/config/sysroot.gni:7
+From //third_party/flutter/common/config.gni:19
-### zircon_args
-[Zircon GN build arguments](../../../zircon/docs/gen/build_arguments.md).
-The default passes through GOMA settings and
-[`select_variant`](#select_variant) shorthand selectors.
-**Only set this if you want to wipe out all the defaults that
-propagate from Fuchsia GN to Zircon GN.** The default value
-folds in [`zircon_extra_args`](#zircon_extra_args), so usually
-it's better to just set `zircon_extra_args` and leave `zircon_args` alone.
-Any individual Zircon build argument set in `zircon_extra_args` will
-silently clobber the default value shown here.
+### skia_enable_particles
-**Current value (from the default):**
-```
-{
- default_deps = [":legacy-arm64"]
- enable_kernel_debugging_features = false
- enable_netsvc_debugging_features = false
- goma_dir = "/home/swarming/goma"
- use_goma = false
- variants = []
-}
-```
+**Current value (from the default):** `true`
-From //build/config/fuchsia/zircon.gni:46
+From //third_party/skia/modules/particles/BUILD.gn:7
-### go_vet_enabled
- go_vet_enabled
- [bool] if false, go vet invocations are disabled for all builds.
+### skia_enable_spirv_validation
**Current value (from the default):** `false`
-From //build/go/go_build.gni:20
+From //third_party/skia/BUILD.gn:47
-### sdk_id
-Identifier for the Core SDK.
+### target_os
**Current value (from the default):** `""`
-From //sdk/config.gni:7
+### linux_runner_extras
+If `true`, the extras.img will be built and mounted inside the container
+at /mnt/chromeos.
-### vk_loader_debug
+This is useful for including some GN-built binaries into the guest image
+without modifying the termina images.
-**Current value (from the default):** `"warn,error"`
+**Current value (from the default):** `false`
-From [//third_party/vulkan_loader_and_validation_layers/loader/BUILD.gn:26](https://fuchsia.googlesource.com/third_party/vulkan_loader_and_validation_layers/+/5aa2763f1d0a436644207f3ab56f40cfbf9bb760/loader/BUILD.gn#26)
+From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:26
-### scenic_enable_vulkan_validation
-Include the vulkan validation layers in scenic.
+### scenic_use_views2
+Temporary flag, switches Flutter to using Scenic's new View API.
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
-From //garnet/bin/ui/BUILD.gn:40
+From //garnet/bin/ui/scenic/config.gni:7
### skia_enable_fontmgr_win
@@ -109,487 +79,407 @@ From //garnet/bin/ui/BUILD.gn:40
From //third_party/skia/BUILD.gn:72
-### icu_use_data_file
-Tells icu to load an external data file rather than rely on the icudata
-being linked directly into the binary.
+### scudo_default_options
+Default [Scudo](https://llvm.org/docs/ScudoHardenedAllocator.html)
+options (before the `SCUDO_OPTIONS` environment variable is read at
+runtime). *NOTE:* This affects only components using the `scudo`
+variant (see GN build argument `select_variant`), and does not affect
+anything when the `use_scudo` build flag is set instead.
-This flag is a bit confusing. As of this writing, icu.gyp set the value to
-0 but common.gypi sets the value to 1 for most platforms (and the 1 takes
-precedence).
+**Current value (from the default):** `["abort_on_error=1", "QuarantineSizeKb=0", "ThreadLocalQuarantineSizeKb=0", "DeallocationTypeMismatch=false", "DeleteSizeMismatch=false", "allocator_may_return_null=true"]`
-TODO(GYP) We'll probably need to enhance this logic to set the value to
-true or false in similar circumstances.
+From //build/config/scudo/scudo.gni:17
+
+### skia_enable_skottie
**Current value (from the default):** `true`
-From [//third_party/icu/config.gni:15](https://fuchsia.googlesource.com/third_party/icu/+/65e4aa3b8cc6b41cf31136b9474a9c97bdc27739/config.gni#15)
+From //third_party/skia/modules/skottie/BUILD.gn:9
-### prebuilt_libvulkan_arm_path
+### skia_llvm_path
**Current value (from the default):** `""`
-From //garnet/lib/magma/gnbuild/magma.gni:23
+From //third_party/skia/BUILD.gn:57
-### skia_use_metal
+### skia_pdf_subset_harfbuzz
+TODO: set skia_pdf_subset_harfbuzz to skia_use_harfbuzz.
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:36
+From //third_party/skia/gn/skia.gni:18
-### skia_use_xps
+### blobfs_minimum_data_bytes
+Number of bytes to reserve for data in the fs. This is in addition
+to what is reserved, if any, for the inodes. Data bytes constitutes
+"usable" space of the fs.
+An empty string does not reserve any additional space than minimum
+required for the filesystem.
-**Current value (from the default):** `true`
+**Current value (from the default):** `""`
-From //third_party/skia/BUILD.gn:39
+From //build/images/fvm.gni:36
-### dart_core_snapshot_kind
-Controls the kind of core snapshot linked into the standalone VM. Using a
-core-jit snapshot breaks the ability to change various flags that affect
-code generation.
+### dart_aot_sharing_basis
+module_suggester is not AOT compiled in debug builds
-**Current value (from the default):** `"core"`
+**Current value (from the default):** `""`
-From //third_party/dart/runtime/runtime_args.gni:56
+From [//topaz/runtime/dart/dart_component.gni:51](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#51)
-### flutter_aot_sharing_basis
-When AOT compiling, an app will reference objects in the sharing basis's
-snapshot when available instead of writing the objects in its own snapshot.
-The snapshot of the sharing basis app will be included in every other app's
-package and deduplicated by blobfs.
+### rust_warnings
+Sets whether Rust compiler warnings cause errors or not.
+"deny" will make all warnings into errors, while "allow" will ignore warnings
-**Current value (from the default):** `""`
+**Current value (from the default):** `"deny"`
-From [//topaz/runtime/dart/dart_component.gni:27](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#27)
+From //build/rust/config.gni:27
-### linux_runner_gateway
+### skia_gl_standard
-**Current value (from the default):** `"10.0.0.1"`
+**Current value (from the default):** `""`
-From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:18
+From //third_party/skia/BUILD.gn:80
-### skia_enable_nima
+### skia_use_libwebp
-**Current value (from the default):** `false`
+**Current value for `target_cpu = "arm64"`:** `false`
-From //third_party/skia/BUILD.gn:45
+From //.gn:29
-### skia_use_harfbuzz
+**Overridden from the default:** `false`
-**Current value (from the default):** `true`
+From //third_party/skia/BUILD.gn:30
-From //third_party/skia/gn/skia.gni:14
+**Current value for `target_cpu = "x64"`:** `false`
-### board_name
-Board name used for paving and amber updates.
+From //.gn:29
-**Current value for `target_cpu = "arm64"`:** `"qemu-arm64"`
+**Overridden from the default:** `false`
-From //boards/arm64.gni:7
+From //third_party/skia/BUILD.gn:30
-**Overridden from the default:** `""`
+### skia_version
-From //build/package.gni:21
+**Current value (from the default):** `""`
-**Current value for `target_cpu = "x64"`:** `"pc"`
+From //third_party/flutter/shell/version/version.gni:8
-From //boards/x64.gni:7
+### msd_arm_enable_all_cores
+Enable all 8 cores, which is faster but emits more heat.
-**Overridden from the default:** `""`
+**Current value (from the default):** `true`
-From //build/package.gni:21
+From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:9
-### build_libvulkan_arm_mali
-Targets that will be built as mali vulkan ICDS.
+### update_kernels
+(deprecated) List of kernel images to include in the update (OTA) package.
+If no list is provided, all built kernels are included. The names in the
+list are strings that must match the filename to be included in the update
+package.
**Current value (from the default):** `[]`
-From //garnet/lib/magma/gnbuild/magma.gni:38
+From //build/images/BUILD.gn:498
-### fuchsia_sdk_root
-Consumers of the Fuchsia SDK instantiate templates for various SDK parts at
-a specific spot within their buildroots. The target name for the specific
-part is then derived from the part name as specified in the meta.json
-manifest. Different buildroot instantiate the SDK parts at different
-locations and then set this variable. GN rules can then prefix this variable
-name in SDK builds to the name of the SDK part. This flag is meaningless in
-non-SDK buildroots.
+### skia_tools_require_resources
-**Current value (from the default):** `""`
+**Current value (from the default):** `false`
-From //build/fuchsia/sdk.gni:17
+From //third_party/skia/BUILD.gn:60
-### skia_use_lua
+### skia_use_opencl
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:31
+From //third_party/skia/BUILD.gn:32
-### enable_input_subsystem
+### dart_platform_bytecode
+Whether the VM's platform dill file contains bytecode.
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
-From //garnet/bin/ui/scenic/BUILD.gn:14
+From //third_party/dart/runtime/runtime_args.gni:84
-### framework_packages
+### dart_version
-**Current value (from the default):** `["collection", "flutter", "meta", "typed_data", "vector_math"]`
+**Current value (from the default):** `""`
-From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:8](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/flutter_runner/prebuilt_framework.gni#8)
+From //third_party/flutter/shell/version/version.gni:10
-### is_debug
-Debug build.
+### fvm_slice_size
+The size of the FVM partition images "slice size". The FVM slice size is a
+minimum size of a particular chunk of a partition that is stored within
+FVM. A very small slice size may lead to decreased throughput. A very large
+slice size may lead to wasted space. The selected default size of 8mb is
+selected for conservation of space, rather than performance.
-**Current value (from the default):** `true`
+**Current value (from the default):** `"8388608"`
-From //build/config/BUILDCONFIG.gn:11
+From //build/images/fvm.gni:19
-### known_variants
-List of variants that will form the basis for variant toolchains.
-To make use of a variant, set [`select_variant`](#select_variant).
+### goma_dir
+Absolute directory containing the Goma source code.
-Normally this is not set as a build argument, but it serves to
-document the available set of variants.
-See also [`universal_variants`](#universal_variants).
-Only set this to remove all the default variants here.
-To add more, set [`extra_variants`](#extra_variants) instead.
-
-Each element of the list is one variant, which is a scope defining:
-
- `configs` (optional)
- [list of labels] Each label names a config that will be
- automatically used by every target built in this variant.
- For each config `${label}`, there must also be a target
- `${label}_deps`, which each target built in this variant will
- automatically depend on. The `variant()` template is the
- recommended way to define a config and its `_deps` target at
- the same time.
+**Current value (from the default):** `"/home/swarming/goma"`
- `remove_common_configs` (optional)
- `remove_shared_configs` (optional)
- [list of labels] This list will be removed (with `-=`) from
- the `default_common_binary_configs` list (or the
- `default_shared_library_configs` list, respectively) after
- all other defaults (and this variant's configs) have been
- added.
+From //build/toolchain/goma.gni:12
- `deps` (optional)
- [list of labels] Added to the deps of every target linked in
- this variant (as well as the automatic `${label}_deps` for
- each label in configs).
+### vk_loader_debug
- `name` (required if configs is omitted)
- [string] Name of the variant as used in
- [`select_variant`](#select_variant) elements' `variant` fields.
- It's a good idea to make it something concise and meaningful when
- seen as e.g. part of a directory name under `$root_build_dir`.
- If name is omitted, configs must be nonempty and the simple names
- (not the full label, just the part after all `/`s and `:`s) of these
- configs will be used in toolchain names (each prefixed by a "-"),
- so the list of config names forming each variant must be unique
- among the lists in `known_variants + extra_variants`.
+**Current value (from the default):** `"warn,error"`
- `toolchain_args` (optional)
- [scope] Each variable defined in this scope overrides a
- build argument in the toolchain context of this variant.
+From [//third_party/vulkan_loader_and_validation_layers/loader/BUILD.gn:26](https://fuchsia.googlesource.com/third_party/vulkan_loader_and_validation_layers/+/5aa2763f1d0a436644207f3ab56f40cfbf9bb760/loader/BUILD.gn#26)
- `host_only` (optional)
- `target_only` (optional)
- [scope] This scope can contain any of the fields above.
- These values are used only for host or target, respectively.
- Any fields included here should not also be in the outer scope.
+### toolchain_manifests
+Manifest files describing target libraries from toolchains.
+Can be either // source paths or absolute system paths.
+**Current value (from the default):** `["/b/s/w/ir/k/buildtools/linux-x64/clang/lib/aarch64-fuchsia.manifest"]`
-**Current value (from the default):**
-```
-[{
- configs = ["//build/config/lto"]
-}, {
- configs = ["//build/config/lto:thinlto"]
-}, {
- configs = ["//build/config/profile"]
-}, {
- configs = ["//build/config/scudo"]
-}, {
- configs = ["//build/config/sanitizers:ubsan"]
-}, {
- configs = ["//build/config/sanitizers:ubsan", "//build/config/sanitizers:sancov"]
-}, {
- configs = ["//build/config/sanitizers:asan"]
- host_only = {
- remove_shared_configs = ["//build/config:symbol_no_undefined"]
-}
- toolchain_args = {
- use_scudo = false
-}
-}, {
- configs = ["//build/config/sanitizers:asan", "//build/config/sanitizers:sancov"]
- host_only = {
- remove_shared_configs = ["//build/config:symbol_no_undefined"]
-}
- toolchain_args = {
- use_scudo = false
-}
-}, {
- configs = ["//build/config/sanitizers:asan"]
- host_only = {
- remove_shared_configs = ["//build/config:symbol_no_undefined"]
-}
- name = "asan_no_detect_leaks"
- toolchain_args = {
- asan_default_options = "detect_leaks=0"
- use_scudo = false
-}
-}, {
- configs = ["//build/config/sanitizers:asan", "//build/config/sanitizers:fuzzer"]
- host_only = {
- remove_shared_configs = ["//build/config:symbol_no_undefined"]
-}
- remove_shared_configs = ["//build/config:symbol_no_undefined"]
- toolchain_args = {
- asan_default_options = "alloc_dealloc_mismatch=0"
- use_scudo = false
-}
-}, {
- configs = ["//build/config/sanitizers:ubsan", "//build/config/sanitizers:fuzzer"]
- remove_shared_configs = ["//build/config:symbol_no_undefined"]
-}]
-```
+From //build/images/manifest.gni:11
-From //build/config/BUILDCONFIG.gn:338
+### export_x64_sdk_images
-### select_variant_canonical
-*This should never be set as a build argument.*
-It exists only to be set in `toolchain_args`.
-See //build/toolchain/clang_toolchain.gni for details.
+**Current value (from the default):** `false`
-**Current value (from the default):** `[]`
+From //sdk/BUILD.gn:13
-From //build/config/BUILDCONFIG.gn:631
+### skia_lex
-### target_cpu
+**Current value (from the default):** `false`
-**Current value for `target_cpu = "arm64"`:** `"arm64"`
+From //third_party/skia/BUILD.gn:53
-From //boards/arm64.gni:5
+### skia_use_angle
-**Overridden from the default:** `""`
+**Current value (from the default):** `false`
-**Current value for `target_cpu = "x64"`:** `"x64"`
+From //third_party/skia/BUILD.gn:21
-From //boards/x64.gni:5
+### skia_use_x11
-**Overridden from the default:** `""`
+**Current value for `target_cpu = "arm64"`:** `false`
-### active_partition
+From //.gn:31
-**Current value (from the default):** `""`
+**Overridden from the default:** `false`
-From //build/images/BUILD.gn:45
+From //third_party/skia/BUILD.gn:38
-### data_partition_manifest
-Path to manifest file containing data to place into the initial /data
-partition.
+**Current value for `target_cpu = "x64"`:** `false`
-**Current value (from the default):** `""`
+From //.gn:31
-From //build/images/BUILD.gn:28
+**Overridden from the default:** `false`
-### build_libvulkan_img_rgx
-Targets that will be built as IMG vulkan ICDS.
+From //third_party/skia/BUILD.gn:38
-**Current value (from the default):** `[]`
+### custom_signing_script
+If non-empty, the given script will be invoked to produce a signed ZBI
+image. The given script must accept -z for the input zbi path, and -o for
+the output signed zbi path. The path must be in GN-label syntax (i.e.
+starts with //).
-From //garnet/lib/magma/gnbuild/magma.gni:47
+**Current value (from the default):** `""`
-### skia_enable_pdf
+From //build/images/custom_signing.gni:12
-**Current value for `target_cpu = "arm64"`:** `false`
+### persist_logs
-From //.gn:25
+**Current value (from the default):** `true`
-**Overridden from the default:** `true`
+From //build/persist_logs.gni:13
-From //third_party/skia/BUILD.gn:46
+### rustc_prefix
+Sets a custom base directory for `rustc` and `cargo`.
+This can be used to test custom Rust toolchains.
-**Current value for `target_cpu = "x64"`:** `false`
+**Current value (from the default):** `"//buildtools/linux-x64/rust/bin"`
-From //.gn:25
+From //build/rust/config.gni:17
-**Overridden from the default:** `true`
+### skia_use_libpng
-From //third_party/skia/BUILD.gn:46
+**Current value (from the default):** `true`
-### toolchain_manifests
-Manifest files describing target libraries from toolchains.
-Can be either // source paths or absolute system paths.
+From //third_party/skia/BUILD.gn:29
-**Current value (from the default):** `["/b/s/w/ir/k/buildtools/linux-x64/clang/lib/aarch64-fuchsia.manifest"]`
+### use_lto
+Use link time optimization (LTO).
-From //build/images/manifest.gni:11
+**Current value (from the default):** `false`
-### zircon_asserts
+From //build/config/lto/config.gni:7
-**Current value (from the default):** `true`
+### vbmeta_a_partition
-From //build/config/fuchsia/BUILD.gn:205
+**Current value (from the default):** `""`
-### bootfs_extra
-List of extra manifest entries for files to add to the BOOTFS.
-Each entry can be a "TARGET=SOURCE" string, or it can be a scope
-with `sources` and `outputs` in the style of a copy() target:
-`outputs[0]` is used as `TARGET` (see `gn help source_expansion`).
+From //build/images/BUILD.gn:42
-**Current value (from the default):** `[]`
+### enable_dart_analysis
+Enable all dart analysis
-From //build/images/BUILD.gn:492
+**Current value (from the default):** `true`
-### scenic_use_views2
-Temporary flag, switches Flutter to using Scenic's new View API.
+From //build/dart/dart_library.gni:15
-**Current value (from the default):** `false`
+### ledger_sync_credentials_file
-From //garnet/bin/ui/scenic/config.gni:7
+**Current value (from the default):** `""`
-### skia_use_opencl
+From //src/ledger/bin/testing/sync_params.gni:6
-**Current value (from the default):** `false`
+### skia_android_serial
-From //third_party/skia/BUILD.gn:32
+**Current value (from the default):** `""`
-### allow_layer_guesswork
-Does nothing.
+From //third_party/skia/BUILD.gn:41
-Will be removed after 30 April 2019.
+### target_sysroot
+The absolute path of the sysroot that is used with the target toolchain.
-**Current value (from the default):** `false`
+**Current value (from the default):** `""`
-From //BUILD.gn:39
+From //build/config/sysroot.gni:7
-### escher_use_null_vulkan_config_on_host
-Using Vulkan on host (i.e. Linux) is an involved affair that involves
-downloading the Vulkan SDK, setting environment variables, and so forth...
-all things that are difficult to achieve in a CQ environment. Therefore,
-by default we use a stub implementation of Vulkan which fails to create a
-VkInstance. This allows everything to build, and also allows running Escher
-unit tests which don't require Vulkan.
+### wlancfg_config_type
+Selects the wlan configuration type to use. Choices:
+ "client" - client mode
+ "ap" - access point mode
+ "" (empty string) - no configuration
-**Current value (from the default):** `true`
+**Current value (from the default):** `"client"`
-From //src/ui/lib/escher/BUILD.gn:16
+From //src/connectivity/wlan/wlancfg/BUILD.gn:15
-### clang_prefix
-The default clang toolchain provided by the buildtools. This variable is
-additionally consumed by the Go toolchain.
+### prebuilt_framework_path
-**Current value (from the default):** `"../buildtools/linux-x64/clang/bin"`
+**Current value (from the default):** `""`
-From //build/config/clang/clang.gni:11
+From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:6](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/flutter_runner/prebuilt_framework.gni#6)
-### using_fuchsia_sdk
-Only set in buildroots where targets configure themselves for use with the
-Fuchsia SDK
+### select_variant
+List of "selectors" to request variant builds of certain targets.
+Each selector specifies matching criteria and a chosen variant.
+The first selector in the list to match a given target determines
+which variant is used for that target.
-**Current value (from the default):** `false`
+Each selector is either a string or a scope. A shortcut selector is
+a string; it gets expanded to a full selector. A full selector is a
+scope, described below.
-From //build/fuchsia/sdk.gni:8
+A string selector can match a name in
+[`select_variant_shortcuts`](#select_variant_shortcuts). If it's not a
+specific shortcut listed there, then it can be the name of any variant
+described in [`known_variants`](#known_variants) and
+[`universal_variants`](#universal_variants) (and combinations thereof).
+A `selector` that's a simple variant name selects for every binary
+built in the target toolchain: `{ host=false variant=selector }`.
-### skia_tools_require_resources
+If a string selector contains a slash, then it's `"shortcut/filename"`
+and selects only the binary in the target toolchain whose `output_name`
+matches `"filename"`, i.e. it adds `output_name=["filename"]` to each
+selector scope that the shortcut's name alone would yield.
-**Current value (from the default):** `false`
+The scope that forms a full selector defines some of these:
-From //third_party/skia/BUILD.gn:60
+ variant (required)
+ [string or `false`] The variant that applies if this selector
+ matches. This can be `false` to choose no variant, or a string
+ that names the variant. See
+ [`known_variants`](#known_variants) and
+ [`universal_variants`](#universal_variants).
-### dart_component_kind
+The rest below are matching criteria. All are optional.
+The selector matches if and only if all of its criteria match.
+If none of these is defined, then the selector always matches.
-**Current value (from the default):** `"static_library"`
+The first selector in the list to match wins and then the rest of
+the list is ignored. So construct more complex rules by using a
+"blacklist" selector with `variant=false` before a catch-all or
+"whitelist" selector that names a variant.
-From //third_party/dart/runtime/runtime_args.gni:80
+Each "[strings]" criterion is a list of strings, and the criterion
+is satisfied if any of the strings matches against the candidate string.
-### linux_runner_netmask
+ host
+ [boolean] If true, the selector matches in the host toolchain.
+ If false, the selector matches in the target toolchain.
-**Current value (from the default):** `"255.255.255.0"`
+ testonly
+ [boolean] If true, the selector matches targets with testonly=true.
+ If false, the selector matches in targets without testonly=true.
-From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:19
+ target_type
+ [strings]: `"executable"`, `"loadable_module"`, or `"driver_module"`
-### blobfs_maximum_bytes
-In addition to reserving space for inodes and data, fs needs additional
-space for maintaining some internal data structures. So the
-space required to reserve inodes and data may exceed sum of the space
-needed for inodes and data.
-maximum_bytes puts an upper bound on the total bytes reserved for inodes,
-data bytes and reservation for all other internal fs metadata.
-An empty string does not put any upper bound. A filesystem may
-reserve few blocks required for its operations.
+ output_name
+ [strings]: target's `output_name` (default: its `target name`)
-**Current value (from the default):** `""`
+ label
+ [strings]: target's full label with `:` (without toolchain suffix)
-From //build/images/fvm.gni:47
+ name
+ [strings]: target's simple name (label after last `/` or `:`)
-### build_info_product
-Product configuration of the current build
+ dir
+ [strings]: target's label directory (`//dir` for `//dir:name`).
-**Current value (from the default):** `""`
+**Current value (from the default):** `[]`
-From //garnet/BUILD.gn:21
+From //build/config/BUILDCONFIG.gn:626
-### skia_enable_fontmgr_android
+### skia_use_libheif
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:70
+From //third_party/skia/BUILD.gn:37
-### base_package_labels
-If you add package labels to this variable, the packages will be included in
-the 'base' package set, which represents the set of packages that are part
-of an OTA. These pacakages are updated as an atomic unit during an OTA
-process and are immutable and are a superset of the TCB (Trusted Computing
-Base) for a product. These packages are never evicted by the system.
+### thinlto_cache_dir
+ThinLTO cache directory path.
-**Current value for `target_cpu = "arm64"`:** `["//garnet/packages/config:kernel_crash_checker", "//garnet/packages/prod:crashpad_agent", "//garnet/packages/prod:feedback_agent", "//garnet/packages/prod:kernel_crash_checker", "//garnet/packages/products:base", "//bundles:kitchen_sink"]`
+**Current value (from the default):** `"thinlto-cache"`
-From //root_build_dir/args.gn:3
+From //build/config/lto/config.gni:16
-**Overridden from the default:** `[]`
+### use_vulkan_loader_for_tests
+Mesa doesn't properly handle loader-less operation;
+their GetInstanceProcAddr implementation returns 0 for some interfaces.
+On ARM there may be multiple libvulkan_arms, so they can't all be linked
+to.
-From //BUILD.gn:14
+**Current value (from the default):** `true`
-**Current value for `target_cpu = "x64"`:** `["//garnet/packages/config:kernel_crash_checker", "//garnet/packages/prod:crashpad_agent", "//garnet/packages/prod:feedback_agent", "//garnet/packages/prod:kernel_crash_checker", "//garnet/packages/products:base", "//bundles:kitchen_sink"]`
+From //garnet/lib/magma/gnbuild/magma.gni:31
-From //root_build_dir/args.gn:3
+### active_partition
-**Overridden from the default:** `[]`
+**Current value (from the default):** `""`
-From //BUILD.gn:14
+From //build/images/BUILD.gn:45
-### dart_default_app
-Controls whether dart_app() targets generate JIT or AOT Dart snapshots.
-This defaults to JIT, use `fx set <ARCH> --args
-'dart_default_app="dart_aot_app"' to switch to AOT.
+### blobfs_minimum_inodes
+minimum_inodes is the number of inodes to reserve for the fs
+An empty string does not reserve any additional space than minimum
+required for the filesystem.
-**Current value (from the default):** `"dart_jit_app"`
+**Current value (from the default):** `""`
-From [//topaz/runtime/dart/dart_component.gni:19](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#19)
+From //build/images/fvm.gni:28
-### extra_variants
-Additional variant toolchain configs to support.
-This is just added to [`known_variants`](#known_variants).
+### msd_intel_gen_build_root
-**Current value (from the default):** `[]`
+**Current value (from the default):** `"//garnet/drivers/gpu/msd-intel-gen"`
-From //build/config/BUILDCONFIG.gn:403
+From //garnet/lib/magma/gnbuild/magma.gni:10
-### host_tools_dir
-This is the directory where host tools intended for manual use by
-developers get installed. It's something a developer might put
-into their shell's $PATH. Host tools that are just needed as part
-of the build do not get copied here. This directory is only for
-things that are generally useful for testing or debugging or
-whatnot outside of the GN build itself. These are only installed
-by an explicit install_host_tools() rule (see //build/host.gni).
+### skia_enable_skpicture
-**Current value (from the default):** `"//root_build_dir/tools"`
+**Current value (from the default):** `true`
-From //build/host.gni:13
+From //third_party/skia/BUILD.gn:48
### skia_use_dng_sdk
@@ -597,7 +487,7 @@ From //build/host.gni:13
From //.gn:26
-**Overridden from the default:** `true`
+**Overridden from the default:** `false`
From //third_party/skia/BUILD.gn:63
@@ -605,230 +495,322 @@ From //third_party/skia/BUILD.gn:63
From //.gn:26
-**Overridden from the default:** `true`
+**Overridden from the default:** `false`
From //third_party/skia/BUILD.gn:63
-### build_libvulkan_vsl_gc
-Targets that will be built as verisilicon vulkan ICDS.
+### use_vboot
+Use vboot images
-**Current value (from the default):** `[]`
+**Current value (from the default):** `false`
-From //garnet/lib/magma/gnbuild/magma.gni:41
+From //build/images/boot.gni:11
-### current_os
+### rust_lto
+Sets the default LTO type for rustc bulids.
+
+**Current value (from the default):** `"unset"`
+
+From //build/rust/config.gni:20
+
+### allow_layer_guesswork
+Does nothing.
+
+Will be removed after 30 April 2019.
+
+**Current value (from the default):** `false`
+
+From //BUILD.gn:39
+
+### debian_guest_qcow
+Package the rootfs as a QCOW image (as opposed to a flat file).
+
+**Current value (from the default):** `true`
+
+From //src/virtualization/packages/debian_guest/BUILD.gn:9
+
+### glm_build_root
+
+**Current value (from the default):** `"//third_party/glm"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:11
+
+### fuchsia_vulkan_sdk
+Path to Fuchsia Vulkan SDK
+
+**Current value (from the default):** `"//third_party/vulkan_loader_and_validation_layers"`
+
+From //build/vulkan/config.gni:10
+
+### use_scudo
+TODO(davemoore): Remove this entire mechanism once standalone scudo is the
+default (DNO-442)
+Enable the [Scudo](https://llvm.org/docs/ScudoHardenedAllocator.html)
+memory allocator.
+
+**Current value (from the default):** `false`
+
+From //build/config/scudo/scudo.gni:10
+
+### dart_vm_code_coverage
+Whether to enable code coverage for the standalone VM.
+
+**Current value (from the default):** `false`
+
+From //third_party/dart/runtime/runtime_args.gni:39
+
+### engine_version
**Current value (from the default):** `""`
-### use_mock_magma
+From //third_party/flutter/shell/version/version.gni:6
+
+### skia_compile_processors
**Current value (from the default):** `false`
-From [//third_party/mesa/src/intel/vulkan/BUILD.gn:25](https://fuchsia.googlesource.com/third_party/mesa/+/232bf12b10899d335a3fe69d947a738541ace7d3/src/intel/vulkan/BUILD.gn#25)
+From //third_party/skia/BUILD.gn:51
+
+### dart_custom_version_for_pub
+When this argument is a non-empty string, the version repoted by the
+Dart VM will be one that is compatible with pub's interpretation of
+semantic version strings. The version string will also include the values
+of the argument. In particular the version string will read:
+
+ "M.m.p-dev.x.x-$(dart_custom_version_for_pub)-$(short_git_hash)"
+
+Where 'M', 'm', and 'p' are the major, minor and patch version numbers,
+and 'dev.x.x' is the dev version tag most recently preceeding the current
+revision. The short git hash can be omitted by setting
+dart_version_git_info=false
+
+**Current value (from the default):** `""`
+
+From //third_party/dart/runtime/runtime_args.gni:73
-### magma_build_root
+### extra_manifest_args
+Extra args to globally apply to the manifest generation script.
-**Current value (from the default):** `"//garnet/lib/magma"`
+**Current value (from the default):** `[]`
-From //garnet/lib/magma/gnbuild/magma.gni:8
+From //build/images/manifest.gni:22
-### skia_llvm_path
+### use_thinlto
+Use ThinLTO variant of LTO if use_lto = true.
-**Current value (from the default):** `""`
+**Current value (from the default):** `true`
-From //third_party/skia/BUILD.gn:57
+From //build/config/lto/config.gni:10
-### enable_value_subsystem
+### dart_space_dart
+Whether experimental space dart mode is enabled for Dart applications.
**Current value (from the default):** `false`
-From //garnet/bin/ui/scenic/BUILD.gn:11
-
-### fvm_image_size
-The size in bytes of the FVM partition image to create. Normally this is
-computed to be just large enough to fit the blob and data images. The
-default value is "", which means to size based on inputs. Specifying a size
-that is too small will result in build failure.
+From [//topaz/runtime/dart/dart_component.gni:41](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#41)
-**Current value (from the default):** `""`
+### flutter_default_app
-From //build/images/fvm.gni:12
+**Current value (from the default):** `"flutter_jit_app"`
-### minfs_maximum_bytes
+From [//topaz/runtime/dart/dart_component.gni:12](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#12)
-**Current value (from the default):** `""`
+### zedboot_cmdline_args
+List of kernel command line arguments to bake into the Zedboot image.
+See //zircon/docs/kernel_cmdline.md and
+[`zedboot_devmgr_config`](#zedboot_devmgr_config).
-From //build/images/fvm.gni:48
+**Current value (from the default):** `[]`
-### skia_use_x11
+From //build/images/zedboot/BUILD.gn:17
-**Current value for `target_cpu = "arm64"`:** `false`
+### zircon_extra_args
+[Zircon GN build arguments](../../../zircon/docs/gen/build_arguments.md).
+This is included in the default value of [`zircon_args`](#zircon_args) so
+you can set this to add things there without wiping out the defaults.
+When you set `zircon_args` directly, then this has no effect at all.
+Arguments you set here override any arguments in the default
+`zircon_args`. There is no way to append to a value from the defaults.
+Note that for just setting simple (string-only) values in Zircon GN's
+[`variants`](../../../zircon/docs/gen/build_arguments.md#variants), the
+default [`zircon_args`](#zircon_args) uses a `variants` value derived from
+[`select_variant`](#select_variant) so for simple cases there is no need
+to explicitly set Zircon's `variants` here.
-From //.gn:31
+**Current value (from the default):** `{ }`
-**Overridden from the default:** `true`
+From //build/config/fuchsia/zircon.gni:27
-From //third_party/skia/BUILD.gn:38
+### bootfs_extra
+List of extra manifest entries for files to add to the BOOTFS.
+Each entry can be a "TARGET=SOURCE" string, or it can be a scope
+with `sources` and `outputs` in the style of a copy() target:
+`outputs[0]` is used as `TARGET` (see `gn help source_expansion`).
-**Current value for `target_cpu = "x64"`:** `false`
+**Current value (from the default):** `[]`
-From //.gn:31
+From //build/images/BUILD.gn:492
-**Overridden from the default:** `true`
+### concurrent_link_jobs
+Maximum number of concurrent link jobs.
-From //third_party/skia/BUILD.gn:38
+We often want to run fewer links at once than we do compiles, because
+linking is memory-intensive. The default to use varies by platform and by
+the amount of memory available, so we call out to a script to get the right
+value.
-### signed_image
+**Current value (from the default):** `16`
-**Current value (from the default):** `false`
+From //build/toolchain/BUILD.gn:15
-From //build/images/BUILD.gn:46
+### dart_runtime_mode
+Set the runtime mode. This affects how the runtime is built and what
+features it has. Valid values are:
+'develop' (the default) - VM is built to run as a JIT with all development
+features enabled.
+'profile' - The VM is built to run with AOT compiled code with only the
+CPU profiling features enabled.
+'release' - The VM is built to run with AOT compiled code with no developer
+features enabled.
-### support_insecure_wep
-Enable WEP support.
-Use temporarily for testing driver WEP support.
-This build flag will be replaced by providing
-dedicated WEP specific WLAN targets which products
-can depend on.
+These settings are only used for Flutter, at the moment. A standalone build
+of the Dart VM should leave this set to "develop", and should set
+'is_debug', 'is_release', or 'is_product'.
-**Current value (from the default):** `false`
+TODO(rmacnak): dart_runtime_mode no longer selects whether libdart is build
+for JIT or AOT, since libdart waw split into libdart_jit and
+libdart_precompiled_runtime. We should remove this flag and just set
+dart_debug/dart_product.
-From //src/connectivity/wlan/lib/wep_deprecated/BUILD.gn:15
+**Current value (from the default):** `"develop"`
-### use_ccache
-Set to true to enable compiling with ccache
+From //third_party/dart/runtime/runtime_args.gni:28
-**Current value (from the default):** `false`
+### dart_lib_export_symbols
+Whether libdart should export the symbols of the Dart API.
-From //build/toolchain/ccache.gni:9
+**Current value (from the default):** `true`
-### zircon_r_partition
+From //third_party/dart/runtime/runtime_args.gni:91
-**Current value (from the default):** `""`
+### host_byteorder
-From //build/images/BUILD.gn:41
+**Current value (from the default):** `"undefined"`
-### zxcrypt_key_source
-This argument specifies from where the system should obtain the zxcrypt
-master key to the system data partition.
+From //build/config/host_byteorder.gni:7
-This value be reified as /boot/config/zxcrypt in both the zircon boot image
-and the zedboot boot image, for consumption by fshost and the paver,
-respectively.
+### escher_use_null_vulkan_config_on_host
+Using Vulkan on host (i.e. Linux) is an involved affair that involves
+downloading the Vulkan SDK, setting environment variables, and so forth...
+all things that are difficult to achieve in a CQ environment. Therefore,
+by default we use a stub implementation of Vulkan which fails to create a
+VkInstance. This allows everything to build, and also allows running Escher
+unit tests which don't require Vulkan.
-Acceptable values are:
-* "null": the device should use an all-0's master key, as we lack support
-for any secure on-device storage.
-* "tee": the device is required to have a Trusted Execution Environment
-(TEE) which includes the "keysafe" Trusted Application (associated with the
-KMS service). The zxcrypt master key should be derived from a per-device
-key accessible only to trusted apps running in the TEE.
-* "tee-opportunistic": the device will attempt to use keys from the TEE if
-available, but will fall back to using the null key if the key from the TEE
-does not work, or if the TEE is not functional on this device.
-* "tee-transitional": the device will require the use of a key from the TEE
-for new volume creation, but will continue to try both a TEE-sourced key and
-the null key when unsealing volumes.
+**Current value (from the default):** `true`
-In the future, we may consider adding support for TPMs, or additional logic
-to explicitly support other fallback behavior.
+From //src/ui/lib/escher/BUILD.gn:16
-**Current value (from the default):** `"null"`
+### icu_use_data_file
+Tells icu to load an external data file rather than rely on the icudata
+being linked directly into the binary.
-From //build/images/zxcrypt.gni:29
+This flag is a bit confusing. As of this writing, icu.gyp set the value to
+0 but common.gypi sets the value to 1 for most platforms (and the 1 takes
+precedence).
-### dart_use_tcmalloc
-Whether to link the standalone VM against tcmalloc. The standalone build of
-the VM enables this only for Linux builds.
+TODO(GYP) We'll probably need to enhance this logic to set the value to
+true or false in similar circumstances.
-**Current value (from the default):** `false`
+**Current value (from the default):** `true`
-From //third_party/dart/runtime/runtime_args.gni:47
+From [//third_party/icu/config.gni:15](https://fuchsia.googlesource.com/third_party/icu/+/65e4aa3b8cc6b41cf31136b9474a9c97bdc27739/config.gni#15)
-### rustc_prefix
-Sets a custom base directory for `rustc` and `cargo`.
-This can be used to test custom Rust toolchains.
+### msd_arm_enable_cache_coherency
+With this flag set the system tries to use cache coherent memory if the
+GPU supports it.
-**Current value (from the default):** `"//buildtools/linux-x64/rust/bin"`
+**Current value (from the default):** `true`
-From //build/rust/config.gni:17
+From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:13
-### skia_use_piex
+### prebuilt_framework_name
-**Current value (from the default):** `true`
+**Current value (from the default):** `""`
-From //third_party/skia/BUILD.gn:33
+From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:7](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/flutter_runner/prebuilt_framework.gni#7)
-### use_scudo
-TODO(davemoore): Remove this entire mechanism once standalone scudo is the
-default (DNO-442)
-Enable the [Scudo](https://llvm.org/docs/ScudoHardenedAllocator.html)
-memory allocator.
+### add_qemu_to_build_archives
+Whether to include images necessary to run Fuchsia in QEMU in build
+archives.
**Current value (from the default):** `false`
-From //build/config/scudo/scudo.gni:10
+From //build/images/BUILD.gn:51
-### dart_version
+### board_name
+Board name used for paving and amber updates.
-**Current value (from the default):** `""`
+**Current value for `target_cpu = "arm64"`:** `"qemu-arm64"`
-From //third_party/flutter/shell/version/version.gni:10
+From //boards/arm64.gni:7
-### magma_enable_tracing
-Enable this to include fuchsia tracing capability
+**Overridden from the default:** `""`
-**Current value (from the default):** `true`
+From //build/package.gni:21
-From //garnet/lib/magma/gnbuild/magma.gni:17
+**Current value for `target_cpu = "x64"`:** `"pc"`
-### build_libvulkan_qcom_adreno
-Targets that will be built as qualcomm vulkan ICDS.
+From //boards/x64.gni:7
-**Current value (from the default):** `[]`
+**Overridden from the default:** `""`
-From //garnet/lib/magma/gnbuild/magma.gni:44
+From //build/package.gni:21
-### enable_mdns_trace
-Enables the tracing feature of mdns, which can be turned on using
-"mdns-util verbose".
+### board_packages
-**Current value (from the default):** `false`
+**Current value for `target_cpu = "arm64"`:** `[]`
-From //src/connectivity/network/mdns/service/BUILD.gn:15
+From //boards/arm64.gni:9
-### use_vboot
-Use vboot images
+**Overridden from the default:** `[]`
-**Current value (from the default):** `false`
+From //BUILD.gn:40
-From //build/images/boot.gni:11
+**Current value for `target_cpu = "x64"`:** `[]`
-### wlancfg_config_type
-Selects the wlan configuration type to use. Choices:
- "client" - client mode
- "ap" - access point mode
- "" (empty string) - no configuration
+From //boards/x64.gni:9
-**Current value (from the default):** `"client"`
+**Overridden from the default:** `[]`
-From //src/connectivity/wlan/wlancfg/BUILD.gn:15
+From //BUILD.gn:40
-### zedboot_cmdline_files
-Files containing additional kernel command line arguments to bake into
-the Zedboot image. The contents of these files (in order) come after any
-arguments directly in [`zedboot_cmdline_args`](#zedboot_cmdline_args).
-These can be GN `//` source pathnames or absolute system pathnames.
+### fuchsia_sdk_root
+Consumers of the Fuchsia SDK instantiate templates for various SDK parts at
+a specific spot within their buildroots. The target name for the specific
+part is then derived from the part name as specified in the meta.json
+manifest. Different buildroot instantiate the SDK parts at different
+locations and then set this variable. GN rules can then prefix this variable
+name in SDK builds to the name of the SDK part. This flag is meaningless in
+non-SDK buildroots.
+
+**Current value (from the default):** `""`
-**Current value (from the default):** `[]`
+From //build/fuchsia/sdk.gni:17
-From //build/images/zedboot/BUILD.gn:23
+### msd_arm_enable_protected_debug_swap_mode
+In protected mode, faults don't return as much information so they're much harder to debug. To
+work around that, add a mode where protected atoms are executed in non-protected mode and
+vice-versa.
-### flutter_profile
+NOTE: The memory security ranges should also be set (in TrustZone) to the opposite of normal, so
+that non-protected mode accesses can only access protected memory and vice versa. Also,
+growable memory faults won't work in this mode, so larger portions of growable memory should
+precommitted (which is not done by default).
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
-From [//topaz/runtime/dart/dart_component.gni:32](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#32)
+From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:23
### select_variant_shortcuts
List of short names for commonly-used variant selectors. Normally this
@@ -863,460 +845,519 @@ a list that can be spliced into [`select_variant`](#select_variant).
From //build/config/BUILDCONFIG.gn:449
-### minfs_minimum_data_bytes
-
-**Current value (from the default):** `""`
-
-From //build/images/fvm.gni:37
-
-### scenic_ignore_vsync
+### skia_use_fonthost_mac
**Current value (from the default):** `false`
-From //garnet/lib/ui/gfx/BUILD.gn:8
-
-### zircon_enable_netsvc_debugging_features
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //products/core.gni:10
-
-**Overridden from the default:** `false`
-
-From //build/config/fuchsia/zircon.gni:33
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //products/core.gni:10
-
-**Overridden from the default:** `false`
-
-From //build/config/fuchsia/zircon.gni:33
+From //third_party/skia/BUILD.gn:25
-### full_dart_sdk
+### clang_prefix
+The default clang toolchain provided by the buildtools. This variable is
+additionally consumed by the Go toolchain.
-**Current value (from the default):** `false`
+**Current value (from the default):** `"../buildtools/linux-x64/clang/bin"`
-From //third_party/flutter/BUILD.gn:14
+From //build/config/clang/clang.gni:11
-### log_startup_sleep
+### skia_use_zlib
-**Current value (from the default):** `"30000"`
+**Current value (from the default):** `true`
-From //garnet/bin/log_listener/BUILD.gn:14
+From //third_party/skia/BUILD.gn:35
-### board_packages
+### use_prebuilt_ffmpeg
+Use a prebuilt ffmpeg binary rather than building it locally. See
+//src/media/lib/ffmpeg/README.md for details. This is ignored when
+building in variant builds for which there is no prebuilt. In that
+case, ffmpeg is always built from source so as to be built with the
+selected variant's config. When this is false (either explicitly or in
+a variant build) then //third_party/ffmpeg must be in the source tree,
+which requires:
+`jiri import -name integration third_party/ffmpeg https://fuchsia.googlesource.com/integration`
-**Current value for `target_cpu = "arm64"`:** `[]`
+**Current value (from the default):** `true`
-From //boards/arm64.gni:9
+From //src/media/lib/ffmpeg/BUILD.gn:14
-**Overridden from the default:** `[]`
+### zircon_asserts
-From //BUILD.gn:40
+**Current value (from the default):** `true`
-**Current value for `target_cpu = "x64"`:** `[]`
+From //build/config/fuchsia/BUILD.gn:205
-From //boards/x64.gni:9
+### zircon_build_root
-**Overridden from the default:** `[]`
+**Current value (from the default):** `"//zircon"`
-From //BUILD.gn:40
+From //garnet/lib/magma/gnbuild/magma.gni:12
-### dart_aot_sharing_basis
-module_suggester is not AOT compiled in debug builds
+### is_debug
+Debug build.
-**Current value (from the default):** `""`
+**Current value (from the default):** `true`
-From [//topaz/runtime/dart/dart_component.gni:51](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#51)
+From //build/config/BUILDCONFIG.gn:11
-### skia_enable_skpicture
+### skia_enable_fontmgr_custom_empty
**Current value (from the default):** `true`
-From //third_party/skia/BUILD.gn:48
+From //third_party/skia/BUILD.gn:69
-### meta_package_labels
-A list of labels for meta packages to be included in the monolith.
+### skia_enable_skshaper
-**Current value for `target_cpu = "arm64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//src/sys/component_index:component_index"]`
+**Current value (from the default):** `true`
-From //products/core.gni:12
+From //third_party/skia/modules/skshaper/BUILD.gn:9
-**Overridden from the default:** `[]`
+### skia_enable_fontmgr_empty
-From //build/images/BUILD.gn:36
+**Current value (from the default):** `false`
-**Current value for `target_cpu = "x64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//src/sys/component_index:component_index"]`
+From //third_party/skia/BUILD.gn:66
-From //products/core.gni:12
+### skia_enable_pdf
-**Overridden from the default:** `[]`
+**Current value for `target_cpu = "arm64"`:** `false`
-From //build/images/BUILD.gn:36
+From //.gn:25
-### skia_compile_processors
+**Overridden from the default:** `true`
-**Current value (from the default):** `false`
+From //third_party/skia/BUILD.gn:46
-From //third_party/skia/BUILD.gn:51
+**Current value for `target_cpu = "x64"`:** `false`
-### skia_enable_fontmgr_custom
+From //.gn:25
-**Current value (from the default):** `true`
+**Overridden from the default:** `true`
-From //third_party/skia/BUILD.gn:68
+From //third_party/skia/BUILD.gn:46
-### skia_enable_tools
+### always_zedboot
+Build boot images that prefer Zedboot over local boot (only for EFI).
**Current value (from the default):** `false`
-From //third_party/skia/gn/skia.gni:12
+From //build/images/BUILD.gn:809
-### skia_use_fixed_gamma_text
+### enable_gfx_subsystem
-**Current value (from the default):** `false`
+**Current value (from the default):** `true`
-From //third_party/skia/BUILD.gn:27
+From //garnet/bin/ui/scenic/BUILD.gn:12
-### use_lto
-Use link time optimization (LTO).
+### go_vet_enabled
+ go_vet_enabled
+ [bool] if false, go vet invocations are disabled for all builds.
**Current value (from the default):** `false`
-From //build/config/lto/config.gni:7
-
-### host_byteorder
-
-**Current value (from the default):** `"undefined"`
+From //build/go/go_build.gni:20
-From //build/config/host_byteorder.gni:7
+### fastboot_product
-### host_cpu
+**Current value (from the default):** `""`
-**Current value (from the default):** `"x64"`
+From //build/images/BUILD.gn:47
-### zedboot_cmdline_args
-List of kernel command line arguments to bake into the Zedboot image.
-See //zircon/docs/kernel_cmdline.md and
-[`zedboot_devmgr_config`](#zedboot_devmgr_config).
+### known_variants
+List of variants that will form the basis for variant toolchains.
+To make use of a variant, set [`select_variant`](#select_variant).
-**Current value (from the default):** `[]`
+Normally this is not set as a build argument, but it serves to
+document the available set of variants.
+See also [`universal_variants`](#universal_variants).
+Only set this to remove all the default variants here.
+To add more, set [`extra_variants`](#extra_variants) instead.
-From //build/images/zedboot/BUILD.gn:17
+Each element of the list is one variant, which is a scope defining:
-### zedboot_devmgr_config
-List of arguments to populate /boot/config/devmgr in the Zedboot image.
+ `configs` (optional)
+ [list of labels] Each label names a config that will be
+ automatically used by every target built in this variant.
+ For each config `${label}`, there must also be a target
+ `${label}_deps`, which each target built in this variant will
+ automatically depend on. The `variant()` template is the
+ recommended way to define a config and its `_deps` target at
+ the same time.
-**Current value (from the default):** `["netsvc.netboot=true"]`
+ `remove_common_configs` (optional)
+ `remove_shared_configs` (optional)
+ [list of labels] This list will be removed (with `-=`) from
+ the `default_common_binary_configs` list (or the
+ `default_shared_library_configs` list, respectively) after
+ all other defaults (and this variant's configs) have been
+ added.
-From //build/images/zedboot/BUILD.gn:26
+ `deps` (optional)
+ [list of labels] Added to the deps of every target linked in
+ this variant (as well as the automatic `${label}_deps` for
+ each label in configs).
-### skia_enable_flutter_defines
+ `name` (required if configs is omitted)
+ [string] Name of the variant as used in
+ [`select_variant`](#select_variant) elements' `variant` fields.
+ It's a good idea to make it something concise and meaningful when
+ seen as e.g. part of a directory name under `$root_build_dir`.
+ If name is omitted, configs must be nonempty and the simple names
+ (not the full label, just the part after all `/`s and `:`s) of these
+ configs will be used in toolchain names (each prefixed by a "-"),
+ so the list of config names forming each variant must be unique
+ among the lists in `known_variants + extra_variants`.
-**Current value for `target_cpu = "arm64"`:** `true`
+ `toolchain_args` (optional)
+ [scope] Each variable defined in this scope overrides a
+ build argument in the toolchain context of this variant.
-From //.gn:24
+ `host_only` (optional)
+ `target_only` (optional)
+ [scope] This scope can contain any of the fields above.
+ These values are used only for host or target, respectively.
+ Any fields included here should not also be in the outer scope.
-**Overridden from the default:** `false`
-From //third_party/skia/BUILD.gn:17
+**Current value (from the default):**
+```
+[{
+ configs = ["//build/config/lto"]
+}, {
+ configs = ["//build/config/lto:thinlto"]
+}, {
+ configs = ["//build/config/profile"]
+}, {
+ configs = ["//build/config/scudo"]
+}, {
+ configs = ["//build/config/sanitizers:ubsan"]
+}, {
+ configs = ["//build/config/sanitizers:ubsan", "//build/config/sanitizers:sancov"]
+}, {
+ configs = ["//build/config/sanitizers:asan"]
+ host_only = {
+ remove_shared_configs = ["//build/config:symbol_no_undefined"]
+}
+ toolchain_args = {
+ use_scudo = false
+}
+}, {
+ configs = ["//build/config/sanitizers:asan", "//build/config/sanitizers:sancov"]
+ host_only = {
+ remove_shared_configs = ["//build/config:symbol_no_undefined"]
+}
+ toolchain_args = {
+ use_scudo = false
+}
+}, {
+ configs = ["//build/config/sanitizers:asan"]
+ host_only = {
+ remove_shared_configs = ["//build/config:symbol_no_undefined"]
+}
+ name = "asan_no_detect_leaks"
+ toolchain_args = {
+ asan_default_options = "detect_leaks=0"
+ use_scudo = false
+}
+}, {
+ configs = ["//build/config/sanitizers:asan", "//build/config/sanitizers:fuzzer"]
+ host_only = {
+ remove_shared_configs = ["//build/config:symbol_no_undefined"]
+}
+ remove_shared_configs = ["//build/config:symbol_no_undefined"]
+ toolchain_args = {
+ asan_default_options = "alloc_dealloc_mismatch=0"
+ use_scudo = false
+}
+}, {
+ configs = ["//build/config/sanitizers:ubsan", "//build/config/sanitizers:fuzzer"]
+ remove_shared_configs = ["//build/config:symbol_no_undefined"]
+}]
+```
-**Current value for `target_cpu = "x64"`:** `true`
+From //build/config/BUILDCONFIG.gn:338
-From //.gn:24
+### rust_toolchain_triple_suffix
+Sets the fuchsia toolchain target triple suffix (after arch)
-**Overridden from the default:** `false`
+**Current value (from the default):** `"fuchsia"`
-From //third_party/skia/BUILD.gn:17
+From //build/rust/config.gni:23
-### skia_use_libwebp
+### skia_enable_atlas_text
-**Current value for `target_cpu = "arm64"`:** `false`
+**Current value (from the default):** `false`
-From //.gn:29
+From //third_party/skia/BUILD.gn:65
-**Overridden from the default:** `true`
+### zxcrypt_key_source
+This argument specifies from where the system should obtain the zxcrypt
+master key to the system data partition.
-From //third_party/skia/BUILD.gn:30
+This value be reified as /boot/config/zxcrypt in both the zircon boot image
+and the zedboot boot image, for consumption by fshost and the paver,
+respectively.
-**Current value for `target_cpu = "x64"`:** `false`
+Acceptable values are:
+* "null": the device should use an all-0's master key, as we lack support
+for any secure on-device storage.
+* "tee": the device is required to have a Trusted Execution Environment
+(TEE) which includes the "keysafe" Trusted Application (associated with the
+KMS service). The zxcrypt master key should be derived from a per-device
+key accessible only to trusted apps running in the TEE.
+* "tee-opportunistic": the device will attempt to use keys from the TEE if
+available, but will fall back to using the null key if the key from the TEE
+does not work, or if the TEE is not functional on this device.
+* "tee-transitional": the device will require the use of a key from the TEE
+for new volume creation, but will continue to try both a TEE-sourced key and
+the null key when unsealing volumes.
-From //.gn:29
+In the future, we may consider adding support for TPMs, or additional logic
+to explicitly support other fallback behavior.
-**Overridden from the default:** `true`
+**Current value (from the default):** `"null"`
-From //third_party/skia/BUILD.gn:30
+From //build/images/zxcrypt.gni:29
-### thinlto_cache_dir
-ThinLTO cache directory path.
+### build_libvulkan_qcom_adreno
+Targets that will be built as qualcomm vulkan ICDS.
-**Current value (from the default):** `"linux_x64/thinlto-cache"`
+**Current value (from the default):** `[]`
-From //build/config/lto/config.gni:16
+From //garnet/lib/magma/gnbuild/magma.gni:44
-### prebuilt_framework_path
+### dart_debug_optimization_level
+The optimization level to use for debug builds. Defaults to 0 for builds with
+code coverage enabled.
-**Current value (from the default):** `""`
+**Current value (from the default):** `"2"`
-From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:6](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/flutter_runner/prebuilt_framework.gni#6)
+From //third_party/dart/runtime/runtime_args.gni:36
-### select_variant
-List of "selectors" to request variant builds of certain targets.
-Each selector specifies matching criteria and a chosen variant.
-The first selector in the list to match a given target determines
-which variant is used for that target.
+### experimental_wlan_client_mlme
+Selects the SoftMAC client implementation to use. Choices:
+ false (default) - C++ Client MLME implementation
+ true - Rust Client MLME implementation
+This argument is temporary until Rust MLME is ready to be used.
-Each selector is either a string or a scope. A shortcut selector is
-a string; it gets expanded to a full selector. A full selector is a
-scope, described below.
+**Current value (from the default):** `false`
-A string selector can match a name in
-[`select_variant_shortcuts`](#select_variant_shortcuts). If it's not a
-specific shortcut listed there, then it can be the name of any variant
-described in [`known_variants`](#known_variants) and
-[`universal_variants`](#universal_variants) (and combinations thereof).
-A `selector` that's a simple variant name selects for every binary
-built in the target toolchain: `{ host=false variant=selector }`.
+From //src/connectivity/wlan/lib/mlme/cpp/BUILD.gn:10
-If a string selector contains a slash, then it's `"shortcut/filename"`
-and selects only the binary in the target toolchain whose `output_name`
-matches `"filename"`, i.e. it adds `output_name=["filename"]` to each
-selector scope that the shortcut's name alone would yield.
+### build_info_board
+Board configuration of the current build
-The scope that forms a full selector defines some of these:
+**Current value (from the default):** `"qemu-arm64"`
- variant (required)
- [string or `false`] The variant that applies if this selector
- matches. This can be `false` to choose no variant, or a string
- that names the variant. See
- [`known_variants`](#known_variants) and
- [`universal_variants`](#universal_variants).
+From //garnet/BUILD.gn:24
-The rest below are matching criteria. All are optional.
-The selector matches if and only if all of its criteria match.
-If none of these is defined, then the selector always matches.
+### host_tools_dir
+This is the directory where host tools intended for manual use by
+developers get installed. It's something a developer might put
+into their shell's $PATH. Host tools that are just needed as part
+of the build do not get copied here. This directory is only for
+things that are generally useful for testing or debugging or
+whatnot outside of the GN build itself. These are only installed
+by an explicit install_host_tools() rule (see //build/host.gni).
-The first selector in the list to match wins and then the rest of
-the list is ignored. So construct more complex rules by using a
-"blacklist" selector with `variant=false` before a catch-all or
-"whitelist" selector that names a variant.
+**Current value (from the default):** `"//root_build_dir/tools"`
-Each "[strings]" criterion is a list of strings, and the criterion
-is satisfied if any of the strings matches against the candidate string.
+From //build/host.gni:13
- host
- [boolean] If true, the selector matches in the host toolchain.
- If false, the selector matches in the target toolchain.
+### zircon_b_partition
- testonly
- [boolean] If true, the selector matches targets with testonly=true.
- If false, the selector matches in targets without testonly=true.
+**Current value (from the default):** `""`
- target_type
- [strings]: `"executable"`, `"loadable_module"`, or `"driver_module"`
+From //build/images/BUILD.gn:40
- output_name
- [strings]: target's `output_name` (default: its `target name`)
+### skia_use_xps
- label
- [strings]: target's full label with `:` (without toolchain suffix)
+**Current value (from the default):** `true`
- name
- [strings]: target's simple name (label after last `/` or `:`)
+From //third_party/skia/BUILD.gn:39
- dir
- [strings]: target's label directory (`//dir` for `//dir:name`).
+### vbmeta_b_partition
-**Current value (from the default):** `[]`
+**Current value (from the default):** `""`
-From //build/config/BUILDCONFIG.gn:626
+From //build/images/BUILD.gn:43
-### msd_intel_gen_build_root
+### skia_use_libjpeg_turbo
-**Current value (from the default):** `"//garnet/drivers/gpu/msd-intel-gen"`
+**Current value (from the default):** `true`
-From //garnet/lib/magma/gnbuild/magma.gni:10
+From //third_party/skia/BUILD.gn:28
-### concurrent_rust_jobs
-Maximum number of Rust processes to run in parallel.
+### sdk_dirs
+The directories to search for parts of the SDK.
-We run multiple rustc jobs in parallel, each of which can cause significant
-amount of memory, especially when using LTO. To avoid out-of-memory errors
-we explicitly reduce the number of jobs.
+By default, we search the public directories for the various layers.
+In the future, we'll search a pre-built SDK as well.
-**Current value (from the default):** `14`
+**Current value (from the default):** `["//garnet/public", "//peridot/public", "//topaz/public"]`
-From //build/rust/BUILD.gn:15
+From //build/config/fuchsia/sdk.gni:10
-### custom_signing_script
-If non-empty, the given script will be invoked to produce a signed ZBI
-image. The given script must accept -z for the input zbi path, and -o for
-the output signed zbi path. The path must be in GN-label syntax (i.e.
-starts with //).
+### skia_enable_gpu
-**Current value (from the default):** `""`
+**Current value (from the default):** `true`
-From //build/images/custom_signing.gni:12
+From //third_party/skia/gn/skia.gni:11
-### zircon_enable_kernel_debugging_features
-Whether to include various features (non-shipping, insecure, etc.) in the
-kernel or netsvc builds.
+### skia_use_fontconfig
**Current value for `target_cpu = "arm64"`:** `false`
-From //products/core.gni:9
+From //.gn:28
**Overridden from the default:** `false`
-From //build/config/fuchsia/zircon.gni:32
+From //third_party/skia/BUILD.gn:24
**Current value for `target_cpu = "x64"`:** `false`
-From //products/core.gni:9
+From //.gn:28
**Overridden from the default:** `false`
-From //build/config/fuchsia/zircon.gni:32
+From //third_party/skia/BUILD.gn:24
-### skia_enable_fontmgr_win_gdi
+### scenic_enable_vulkan_validation
+Include the vulkan validation layers in scenic.
-**Current value (from the default):** `false`
+**Current value (from the default):** `true`
-From //third_party/skia/BUILD.gn:73
+From //garnet/bin/ui/BUILD.gn:40
-### skia_use_libpng
+### skia_use_metal
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:29
+From //third_party/skia/BUILD.gn:36
-### skia_enable_ccpr
+### crashpad_dependencies
-**Current value (from the default):** `true`
+**Current value (from the default):** `"fuchsia"`
-From //third_party/skia/BUILD.gn:42
+From [//third_party/crashpad/build/crashpad_buildconfig.gni:22](https://chromium.googlesource.com/crashpad/crashpad/+/d221b7cadab5f00c6999f060a5bcb0896e25c7b7/build/crashpad_buildconfig.gni#22)
-### kernel_cmdline_args
-List of kernel command line arguments to bake into the boot image.
-See also //zircon/docs/kernel_cmdline.md and
-[`devmgr_config`](#devmgr_config).
+### extra_variants
+Additional variant toolchain configs to support.
+This is just added to [`known_variants`](#known_variants).
**Current value (from the default):** `[]`
-From //build/images/BUILD.gn:480
-
-### linux_runner_extras
-If `true`, the extras.img will be built and mounted inside the container
-at /mnt/chromeos.
+From //build/config/BUILDCONFIG.gn:403
-This is useful for including some GN-built binaries into the guest image
-without modifying the termina images.
+### full_dart_sdk
**Current value (from the default):** `false`
-From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:26
-
-### magma_python_path
+From //third_party/flutter/BUILD.gn:14
-**Current value (from the default):** `"/b/s/w/ir/k/third_party/mako"`
+### host_os
-From //garnet/lib/magma/gnbuild/magma.gni:14
+**Current value (from the default):** `"linux"`
-### vbmeta_r_partition
+### clang_lib_dir
+Path to Clang lib directory.
-**Current value (from the default):** `""`
+**Current value (from the default):** `"../build/buildtools/linux-x64/clang/lib"`
-From //build/images/BUILD.gn:44
+From //build/images/manifest.gni:19
-### dart_debug
-Instead of using is_debug, we introduce a different flag for specifying a
-Debug build of Dart so that clients can still use a Release build of Dart
-while themselves doing a Debug build.
+### dart_component_kind
+Allow for deduping the VM between standalone, flutter_runner and dart_runner.
-**Current value (from the default):** `false`
+**Current value (from the default):** `"shared_library"`
-From //third_party/dart/runtime/runtime_args.gni:9
+From //third_party/dart/runtime/runtime_args.gni:78
-### skia_use_freetype
+### enable_input_subsystem
**Current value (from the default):** `true`
-From //third_party/skia/BUILD.gn:26
+From //garnet/bin/ui/scenic/BUILD.gn:14
-### dart_runtime_mode
-Set the runtime mode. This affects how the runtime is built and what
-features it has. Valid values are:
-'develop' (the default) - VM is built to run as a JIT with all development
-features enabled.
-'profile' - The VM is built to run with AOT compiled code with only the
-CPU profiling features enabled.
-'release' - The VM is built to run with AOT compiled code with no developer
-features enabled.
+### select_variant_canonical
+*This should never be set as a build argument.*
+It exists only to be set in `toolchain_args`.
+See //build/toolchain/clang_toolchain.gni for details.
-These settings are only used for Flutter, at the moment. A standalone build
-of the Dart VM should leave this set to "develop", and should set
-'is_debug', 'is_release', or 'is_product'.
+**Current value (from the default):** `[]`
-TODO(rmacnak): dart_runtime_mode no longer selects whether libdart is build
-for JIT or AOT, since libdart waw split into libdart_jit and
-libdart_precompiled_runtime. We should remove this flag and just set
-dart_debug/dart_product.
+From //build/config/BUILDCONFIG.gn:631
-**Current value (from the default):** `"develop"`
+### support_insecure_wep
+Enable WEP support.
+Use temporarily for testing driver WEP support.
+This build flag will be replaced by providing
+dedicated WEP specific WLAN targets which products
+can depend on.
-From //third_party/dart/runtime/runtime_args.gni:28
+**Current value (from the default):** `false`
-### skia_enable_vulkan_debug_layers
+From //src/connectivity/wlan/lib/wep_deprecated/BUILD.gn:15
+
+### use_ccache
+Set to true to enable compiling with ccache
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:49
+From //build/toolchain/ccache.gni:9
-### skia_enable_gpu
+### using_fuchsia_sdk
+Only set in buildroots where targets configure themselves for use with the
+Fuchsia SDK
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
-From //third_party/skia/gn/skia.gni:11
+From //build/fuchsia/sdk.gni:8
-### enable_dart_analysis
-Enable all dart analysis
+### blobfs_maximum_bytes
+In addition to reserving space for inodes and data, fs needs additional
+space for maintaining some internal data structures. So the
+space required to reserve inodes and data may exceed sum of the space
+needed for inodes and data.
+maximum_bytes puts an upper bound on the total bytes reserved for inodes,
+data bytes and reservation for all other internal fs metadata.
+An empty string does not put any upper bound. A filesystem may
+reserve few blocks required for its operations.
-**Current value (from the default):** `true`
+**Current value (from the default):** `""`
-From //build/dart/dart_library.gni:15
+From //build/images/fvm.gni:47
-### engine_version
+### extra_authorized_keys_file
+Additional SSH authorized_keys file to include in the build.
+For example:
+ extra_authorized_keys_file=\"$HOME/.ssh/id_rsa.pub\"
**Current value (from the default):** `""`
-From //third_party/flutter/shell/version/version.gni:6
+From [//third_party/openssh-portable/fuchsia/developer-keys/BUILD.gn:11](https://fuchsia.googlesource.com/third_party/openssh-portable/+/62f4ca0d82fa50a3405703837031a15c36dccdd4/fuchsia/developer-keys/BUILD.gn#11)
-### flutter_default_app
+### magma_build_root
-**Current value (from the default):** `"flutter_jit_app"`
+**Current value (from the default):** `"//garnet/lib/magma"`
-From [//topaz/runtime/dart/dart_component.gni:12](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#12)
+From //garnet/lib/magma/gnbuild/magma.gni:8
-### msd_arm_enable_cache_coherency
-With this flag set the system tries to use cache coherent memory if the
-GPU supports it.
+### skia_enable_discrete_gpu
**Current value (from the default):** `true`
-From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:13
+From //third_party/skia/BUILD.gn:44
-### skia_enable_nvpr
+### skia_enable_fontmgr_win_gdi
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:43
+From //third_party/skia/BUILD.gn:73
-### skia_use_libjpeg_turbo
+### zircon_r_partition
-**Current value (from the default):** `true`
+**Current value (from the default):** `""`
-From //third_party/skia/BUILD.gn:28
+From //build/images/BUILD.gn:41
### dart_force_product
Forces all Dart and Flutter apps to build in a specific configuration that
@@ -1326,300 +1367,279 @@ we use to build products.
From [//topaz/runtime/dart/config.gni:10](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/config.gni#10)
-### dart_target_arch
-Explicitly set the target architecture to use a simulator.
-Available options are: arm, arm64, x64, ia32, and dbc.
+### expat_build_root
-**Current value (from the default):** `"arm64"`
+**Current value (from the default):** `"//third_party/expat"`
-From //third_party/dart/runtime/runtime_args.gni:32
+From //garnet/lib/magma/gnbuild/magma.gni:9
-### toolchain_variant
-*This should never be set as a build argument.*
-It exists only to be set in `toolchain_args`.
-See //build/toolchain/clang_toolchain.gni for details.
-This variable is a scope giving details about the current toolchain:
- `toolchain_variant.base`
- [label] The "base" toolchain for this variant, *often the
- right thing to use in comparisons, not `current_toolchain`.*
- This is the toolchain actually referenced directly in GN
- source code. If the current toolchain is not
- `shlib_toolchain` or a variant toolchain, this is the same
- as `current_toolchain`. In one of those derivative
- toolchains, this is the toolchain the GN code probably
- thought it was in. This is the right thing to use in a test
- like `toolchain_variant.base == target_toolchain`, rather
- rather than comparing against `current_toolchain`.
- `toolchain_variant.name`
- [string] The name of this variant, as used in `variant` fields
- in [`select_variant`](#select_variant) clauses. In the base
- toolchain and its `shlib_toolchain`, this is `""`.
- `toolchain_variant.suffix`
- [string] This is "-${toolchain_variant.name}", "" if name is empty.
- `toolchain_variant.is_pic_default`
- [bool] This is true in `shlib_toolchain`.
-The other fields are the variant's effects as defined in
-[`known_variants`](#known_variants).
+### gocache_dir
+ gocache_dir
+ Directory GOCACHE environment variable will be set to. This directory
+ will have build and test results cached, and is safe to be written to
+ concurrently. If overridden, this directory must be a full path.
-**Current value (from the default):**
-```
-{
- base = "//build/toolchain/fuchsia:arm64"
-}
-```
+**Current value (from the default):** `"/b/s/w/ir/k/root_build_dir/.gocache"`
-From //build/config/BUILDCONFIG.gn:74
+From //build/go/go_build.gni:16
-### update_kernels
-(deprecated) List of kernel images to include in the update (OTA) package.
-If no list is provided, all built kernels are included. The names in the
-list are strings that must match the filename to be included in the update
-package.
+### linux_guest_extras_path
-**Current value (from the default):** `[]`
+**Current value (from the default):** `""`
-From //build/images/BUILD.gn:498
+From //src/virtualization/packages/linux_guest/BUILD.gn:13
-### thinlto_jobs
-Number of parallel ThinLTO jobs.
+### skia_qt_path
-**Current value (from the default):** `8`
+**Current value (from the default):** `""`
-From //build/config/lto/config.gni:13
+From //third_party/skia/BUILD.gn:50
-### dart_use_crashpad
-Whether to link Crashpad library for crash handling. Only supported on
-Windows for now.
+### cloudkms_key_dir
-**Current value (from the default):** `false`
+**Current value (from the default):** `"projects/fuchsia-infra/locations/global/keyRings/test-secrets/cryptoKeys"`
-From //third_party/dart/runtime/runtime_args.gni:51
+From //build/testing/secret_spec.gni:8
-### enable_netboot
-Whether to build the netboot zbi by default.
+### crashpad_use_boringssl_for_http_transport_socket
+TODO(scottmg): https://crbug.com/crashpad/266 fuchsia:DX-690: BoringSSL
+was removed from the Fuchsia SDK. Re-enable it when we have a way to acquire
+a BoringSSL lib again.
-You can still build //build/images:netboot explicitly even if enable_netboot is false.
+**Current value (from the default):** `true`
-**Current value for `target_cpu = "arm64"`:** `false`
+From [//third_party/crashpad/util/net/tls.gni:21](https://chromium.googlesource.com/crashpad/crashpad/+/d221b7cadab5f00c6999f060a5bcb0896e25c7b7/util/net/tls.gni#21)
-From //products/core.gni:7
+### dart_version_git_info
+Whether the Dart binary version string should include the git hash and
+git commit time.
-**Overridden from the default:** `false`
+**Current value (from the default):** `true`
-From //build/images/BUILD.gn:33
+From //third_party/dart/runtime/runtime_args.gni:60
-**Current value for `target_cpu = "x64"`:** `false`
+### current_cpu
-From //products/core.gni:7
+**Current value (from the default):** `""`
-**Overridden from the default:** `false`
+### max_fvm_size
+Maximum allowable size for the FVM in a release mode build
+Zero means no limit
-From //build/images/BUILD.gn:33
+**Current value (from the default):** `"0"`
-### skia_enable_discrete_gpu
+From //build/images/max_fvm_size.gni:8
-**Current value (from the default):** `true`
+### scenic_ignore_vsync
-From //third_party/skia/BUILD.gn:44
+**Current value (from the default):** `false`
-### skia_enable_skottie
+From //garnet/lib/ui/gfx/BUILD.gn:8
-**Current value (from the default):** `true`
+### use_goma
+Set to true to enable distributed compilation using Goma.
-From //third_party/skia/modules/skottie/BUILD.gn:9
+**Current value (from the default):** `false`
-### dart_use_fallback_root_certificates
-Whether to fall back to built-in root certificates when they cannot be
-verified at the operating system level.
+From //build/toolchain/goma.gni:9
-**Current value (from the default):** `false`
+### skia_use_freetype
-From //third_party/dart/runtime/runtime_args.gni:43
+**Current value (from the default):** `true`
-### enable_sketchy_subsystem
+From //third_party/skia/BUILD.gn:26
-**Current value (from the default):** `false`
+### build_info_version
+Logical version of the current build. If not set, defaults to the timestamp
+of the most recent update.
-From //garnet/bin/ui/scenic/BUILD.gn:13
+**Current value (from the default):** `""`
-### flutter_runtime_mode
-The runtime mode ("debug", "profile", "release", "dynamic_profile", or "dynamic_release")
+From //garnet/BUILD.gn:28
-**Current value (from the default):** `"debug"`
+### kernel_cmdline_args
+List of kernel command line arguments to bake into the boot image.
+See also //zircon/docs/kernel_cmdline.md and
+[`devmgr_config`](#devmgr_config).
-From //third_party/flutter/common/config.gni:19
+**Current value (from the default):** `[]`
-### glm_build_root
+From //build/images/BUILD.gn:480
-**Current value (from the default):** `"//third_party/glm"`
+### skia_enable_vulkan_debug_layers
-From //garnet/lib/magma/gnbuild/magma.gni:11
+**Current value (from the default):** `false`
-### msd_arm_enable_protected_debug_swap_mode
-In protected mode, faults don't return as much information so they're much harder to debug. To
-work around that, add a mode where protected atoms are executed in non-protected mode and
-vice-versa.
+From //third_party/skia/BUILD.gn:49
-NOTE: The memory security ranges should also be set (in TrustZone) to the opposite of normal, so
-that non-protected mode accesses can only access protected memory and vice versa. Also,
-growable memory faults won't work in this mode, so larger portions of growable memory should
-precommitted (which is not done by default).
+### skia_use_piex
-**Current value (from the default):** `false`
+**Current value (from the default):** `true`
-From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:23
+From //third_party/skia/BUILD.gn:33
-### skia_enable_fontmgr_fuchsia
+### use_prebuilt_dart_sdk
+Whether to use the prebuilt Dart SDK for everything.
+When setting this to false, the preubilt Dart SDK will not be used in
+situations where the version of the SDK matters, but may still be used as an
+optimization where the version does not matter.
-**Current value (from the default):** `false`
+**Current value (from the default):** `true`
-From //third_party/skia/BUILD.gn:71
+From //build/dart/dart.gni:15
-### skia_enable_particles
+### zircon_a_partition
+arguments to fx flash script
-**Current value (from the default):** `true`
+**Current value (from the default):** `""`
-From //third_party/skia/modules/particles/BUILD.gn:7
+From //build/images/BUILD.gn:39
-### skia_use_fonthost_mac
+### minfs_maximum_bytes
-**Current value (from the default):** `false`
+**Current value (from the default):** `""`
-From //third_party/skia/BUILD.gn:25
+From //build/images/fvm.gni:48
-### add_qemu_to_build_archives
-Whether to include images necessary to run Fuchsia in QEMU in build
-archives.
+### skia_enable_nvpr
**Current value (from the default):** `false`
-From //build/images/BUILD.gn:51
+From //third_party/skia/BUILD.gn:43
-### export_x64_sdk_images
+### skia_use_fixed_gamma_text
**Current value (from the default):** `false`
-From //sdk/BUILD.gn:13
+From //third_party/skia/BUILD.gn:27
-### skia_generate_workarounds
+### universe_package_labels
+If you add package labels to this variable, the packages will be included
+in the 'universe' package set, which represents all software that is
+produced that is to be published to a package repository or to the SDK by
+the build. The build system ensures that the universe package set includes
+the base and cache package sets, which means you do not need to redundantly
+include those labels in this variable.
-**Current value (from the default):** `false`
+**Current value for `target_cpu = "arm64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
-From //third_party/skia/BUILD.gn:52
+From //products/core.gni:27
-### extra_manifest_args
-Extra args to globally apply to the manifest generation script.
+**Overridden from the default:** `[]`
-**Current value (from the default):** `[]`
+From //BUILD.gn:30
-From //build/images/manifest.gni:22
+**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
-### fastboot_product
+From //products/core.gni:27
-**Current value (from the default):** `""`
+**Overridden from the default:** `[]`
-From //build/images/BUILD.gn:47
+From //BUILD.gn:30
-### rust_warnings
-Sets whether Rust compiler warnings cause errors or not.
-"deny" will make all warnings into errors, while "allow" will ignore warnings
+### linux_runner_gateway
-**Current value (from the default):** `"deny"`
+**Current value (from the default):** `"10.0.0.1"`
-From //build/rust/config.gni:27
+From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:18
-### skia_use_vulkan
+### skia_enable_fontmgr_android
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:88
+From //third_party/skia/BUILD.gn:70
-### use_prebuilt_ffmpeg
-Use a prebuilt ffmpeg binary rather than building it locally. See
-//src/media/lib/ffmpeg/README.md for details. This is ignored when
-building in variant builds for which there is no prebuilt. In that
-case, ffmpeg is always built from source so as to be built with the
-selected variant's config. When this is false (either explicitly or in
-a variant build) then //third_party/ffmpeg must be in the source tree,
-which requires:
-`jiri import -name integration third_party/ffmpeg https://fuchsia.googlesource.com/integration`
+### system_package_key
+The package key to use for signing Fuchsia packages made by the
+`package()` template (and the `system_image` package). If this
+doesn't exist yet when it's needed, it will be generated. New
+keys can be generated with the `pm -k FILE genkey` host command.
-**Current value (from the default):** `true`
+**Current value (from the default):** `"//build/development.key"`
-From //src/media/lib/ffmpeg/BUILD.gn:14
+From //build/package.gni:18
-### dart_lib_export_symbols
-Whether libdart should export the symbols of the Dart API.
+### create_kernel_service_snapshot
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
-From //third_party/dart/runtime/runtime_args.gni:91
+From //third_party/dart/runtime/runtime_args.gni:101
-### devmgr_config
-List of arguments to add to /boot/config/devmgr.
-These come after synthesized arguments to configure blobfs and pkgfs.
+### dart_use_fallback_root_certificates
+Whether to fall back to built-in root certificates when they cannot be
+verified at the operating system level.
-**Current value (from the default):** `[]`
+**Current value (from the default):** `false`
-From //build/images/BUILD.gn:475
+From //third_party/dart/runtime/runtime_args.gni:43
-### magma_enable_developer_build
-Enable this to have the msd include a suite of tests and invoke them
-automatically when the driver starts.
+### have_secmem_ta
+The secmem TA must be obtained elsewhere and put into the firmware
+directory.
**Current value (from the default):** `false`
-From //garnet/lib/magma/gnbuild/magma.gni:21
+From //garnet/bin/sysmem-assistant/BUILD.gn:44
-### minfs_minimum_inodes
+### prebuilt_dart_sdk
+Directory containing prebuilt Dart SDK.
+This must have in its `bin/` subdirectory `gen_snapshot.OS-CPU` binaries.
+Set to empty for a local build.
-**Current value (from the default):** `""`
+**Current value (from the default):** `"//topaz/tools/prebuilt-dart-sdk/linux-x64"`
-From //build/images/fvm.gni:29
+From //build/dart/dart.gni:9
-### skia_enable_atlas_text
+### skia_enable_nima
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:65
+From //third_party/skia/BUILD.gn:45
-### auto_login_to_guest
-Whether basemgr should automatically login as a persistent guest user.
+### use_vbmeta
+If true, then the paving script will pave vbmeta images to the target device.
+It is assumed that the vbmeta image will be created by the custom_signing_script.
**Current value (from the default):** `false`
-From //peridot/bin/basemgr/BUILD.gn:13
+From //build/images/custom_signing.gni:16
-### linux_runner_ip
-Default values for the guest network configuration.
+### flutter_aot_sharing_basis
+When AOT compiling, an app will reference objects in the sharing basis's
+snapshot when available instead of writing the objects in its own snapshot.
+The snapshot of the sharing basis app will be included in every other app's
+package and deduplicated by blobfs.
-These are currently hard-coded to match what is setup in the virtio-net
-device.
+**Current value (from the default):** `""`
-See //src/virtualization/bin/vmm/device/virtio_net.cc for more details.
+From [//topaz/runtime/dart/dart_component.gni:27](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#27)
-**Current value (from the default):** `"10.0.0.2"`
+### flutter_space_dart
+Whether experimental space dart mode is enabled for Flutter applications.
-From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:17
+**Current value (from the default):** `false`
+
+From [//topaz/runtime/dart/dart_component.gni:38](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#38)
+
+### linux_runner_netmask
+
+**Current value (from the default):** `"255.255.255.0"`
+
+From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:19
### skia_use_icu
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
From //third_party/skia/gn/skia.gni:13
-### symbol_level
-How many symbols to include in the build. This affects the performance of
-the build since the symbols are large and dealing with them is slow.
- 2 means regular build with symbols.
- 1 means minimal symbols, usually enough for backtraces only. Symbols with
-internal linkage (static functions or those in anonymous namespaces) may not
-appear when using this level.
- 0 means no symbols.
+### warn_on_sdk_changes
+Whether to only warn when an SDK has been modified.
+If false, any unacknowledged SDK change will cause a build failure.
-**Current value (from the default):** `2`
+**Current value (from the default):** `false`
-From //build/config/compiler.gni:13
+From //build/sdk/config.gni:8
### concurrent_dart_jobs
Maximum number of Dart processes to run in parallel.
@@ -1632,654 +1652,686 @@ errors we explicitly reduce the number of jobs.
From //build/dart/BUILD.gn:15
-### skia_lex
+### embedder_for_target
+By default, the dynamic library target exposing the embedder API is only
+built for the host. The reasoning is that platforms that have target
+definitions would not need an embedder API because an embedder
+implementation is already provided for said target. This flag allows tbe
+builder to obtain a shared library exposing the embedder API for alternative
+embedder implementations.
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:53
+From //third_party/flutter/shell/platform/embedder/embedder.gni:12
-### skia_use_sfntly
+### skia_use_harfbuzz
-**Current value for `target_cpu = "arm64"`:** `false`
+**Current value (from the default):** `true`
-From //.gn:30
+From //third_party/skia/gn/skia.gni:14
-**Overridden from the default:** `true`
+### flutter_profile
-From //third_party/skia/BUILD.gn:64
+**Current value (from the default):** `true`
-**Current value for `target_cpu = "x64"`:** `false`
+From [//topaz/runtime/dart/dart_component.gni:32](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#32)
-From //.gn:30
+### symbol_level
+How many symbols to include in the build. This affects the performance of
+the build since the symbols are large and dealing with them is slow.
+ 2 means regular build with symbols.
+ 1 means minimal symbols, usually enough for backtraces only. Symbols with
+internal linkage (static functions or those in anonymous namespaces) may not
+appear when using this level.
+ 0 means no symbols.
-**Overridden from the default:** `true`
+**Current value (from the default):** `2`
-From //third_party/skia/BUILD.gn:64
+From //build/config/compiler.gni:13
-### cloudkms_key_dir
+### crash_diagnostics_dir
+Clang crash reports directory path. Use empty path to disable altogether.
-**Current value (from the default):** `"projects/fuchsia-infra/locations/global/keyRings/test-secrets/cryptoKeys"`
+**Current value (from the default):** `"//root_build_dir/clang-crashreports"`
-From //build/testing/secret_spec.gni:8
+From //build/config/BUILD.gn:9
-### ledger_sync_credentials_file
+### dart_core_snapshot_kind
+Controls the kind of core snapshot linked into the standalone VM. Using a
+core-jit snapshot breaks the ability to change various flags that affect
+code generation.
-**Current value (from the default):** `""`
+**Current value (from the default):** `"core"`
-From //src/ledger/bin/testing/sync_params.gni:6
+From //third_party/dart/runtime/runtime_args.gni:56
-### goma_dir
-Absolute directory containing the Goma source code.
+### enable_mdns_trace
+Enables the tracing feature of mdns, which can be turned on using
+"mdns-util verbose".
-**Current value (from the default):** `"/home/swarming/goma"`
+**Current value (from the default):** `false`
-From //build/toolchain/goma.gni:12
+From //src/connectivity/network/mdns/service/BUILD.gn:15
-### scudo_default_options
-Default [Scudo](https://llvm.org/docs/ScudoHardenedAllocator.html)
-options (before the `SCUDO_OPTIONS` environment variable is read at
-runtime). *NOTE:* This affects only components using the `scudo`
-variant (see GN build argument `select_variant`), and does not affect
-anything when the `use_scudo` build flag is set instead.
+### zedboot_devmgr_config
+List of arguments to populate /boot/config/devmgr in the Zedboot image.
-**Current value (from the default):** `["abort_on_error=1", "QuarantineSizeKb=0", "ThreadLocalQuarantineSizeKb=0", "DeallocationTypeMismatch=false", "DeleteSizeMismatch=false", "allocator_may_return_null=true"]`
+**Current value (from the default):** `["netsvc.netboot=true"]`
+
+From //build/images/zedboot/BUILD.gn:26
+
+### enable_netboot
+Whether to build the netboot zbi by default.
+
+You can still build //build/images:netboot explicitly even if enable_netboot is false.
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //products/core.gni:7
+
+**Overridden from the default:** `false`
+
+From //build/images/BUILD.gn:33
-From //build/config/scudo/scudo.gni:17
+**Current value for `target_cpu = "x64"`:** `false`
-### skia_skqp_global_error_tolerance
+From //products/core.gni:7
-**Current value (from the default):** `0`
+**Overridden from the default:** `false`
-From //third_party/skia/BUILD.gn:55
+From //build/images/BUILD.gn:33
-### use_thinlto
-Use ThinLTO variant of LTO if use_lto = true.
+### minfs_minimum_data_bytes
-**Current value (from the default):** `true`
+**Current value (from the default):** `""`
-From //build/config/lto/config.gni:10
+From //build/images/fvm.gni:37
-### embedder_for_target
-By default, the dynamic library target exposing the embedder API is only
-built for the host. The reasoning is that platforms that have target
-definitions would not need an embedder API because an embedder
-implementation is already provided for said target. This flag allows tbe
-builder to obtain a shared library exposing the embedder API for alternative
-embedder implementations.
+### signed_image
**Current value (from the default):** `false`
-From //third_party/flutter/shell/platform/embedder/embedder.gni:12
+From //build/images/BUILD.gn:46
-### flutter_space_dart
-Whether experimental space dart mode is enabled for Flutter applications.
+### zircon_enable_netsvc_debugging_features
-**Current value (from the default):** `false`
+**Current value for `target_cpu = "arm64"`:** `false`
-From [//topaz/runtime/dart/dart_component.gni:38](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#38)
+From //products/core.gni:10
-### skia_enable_fontmgr_empty
+**Overridden from the default:** `false`
-**Current value (from the default):** `false`
+From //build/config/fuchsia/zircon.gni:33
-From //third_party/skia/BUILD.gn:66
+**Current value for `target_cpu = "x64"`:** `false`
-### skia_llvm_lib
+From //products/core.gni:10
-**Current value (from the default):** `"LLVM"`
+**Overridden from the default:** `false`
-From //third_party/skia/BUILD.gn:58
+From //build/config/fuchsia/zircon.gni:33
-### skia_use_angle
+### meta_package_labels
+A list of labels for meta packages to be included in the monolith.
-**Current value (from the default):** `false`
+**Current value for `target_cpu = "arm64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//src/sys/component_index:component_index"]`
-From //third_party/skia/BUILD.gn:21
+From //products/core.gni:12
-### system_package_key
-The package key to use for signing Fuchsia packages made by the
-`package()` template (and the `system_image` package). If this
-doesn't exist yet when it's needed, it will be generated. New
-keys can be generated with the `pm -k FILE genkey` host command.
+**Overridden from the default:** `[]`
-**Current value (from the default):** `"//build/development.key"`
+From //build/images/BUILD.gn:36
-From //build/package.gni:18
+**Current value for `target_cpu = "x64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//src/sys/component_index:component_index"]`
-### use_vulkan_loader_for_tests
-Mesa doesn't properly handle loader-less operation;
-their GetInstanceProcAddr implementation returns 0 for some interfaces.
-On ARM there may be multiple libvulkan_arms, so they can't all be linked
-to.
+From //products/core.gni:12
-**Current value (from the default):** `true`
+**Overridden from the default:** `[]`
-From //garnet/lib/magma/gnbuild/magma.gni:31
+From //build/images/BUILD.gn:36
-### zircon_a_partition
-arguments to fx flash script
+### base_package_labels
+If you add package labels to this variable, the packages will be included in
+the 'base' package set, which represents the set of packages that are part
+of an OTA. These pacakages are updated as an atomic unit during an OTA
+process and are immutable and are a superset of the TCB (Trusted Computing
+Base) for a product. These packages are never evicted by the system.
-**Current value (from the default):** `""`
+**Current value for `target_cpu = "arm64"`:** `["//garnet/packages/config:kernel_crash_checker", "//garnet/packages/prod:crashpad_agent", "//garnet/packages/prod:feedback_agent", "//garnet/packages/prod:kernel_crash_checker", "//garnet/packages/products:base", "//bundles:kitchen_sink"]`
-From //build/images/BUILD.gn:39
+From //root_build_dir/args.gn:3
-### dart_vm_code_coverage
-Whether to enable code coverage for the standalone VM.
+**Overridden from the default:** `[]`
-**Current value (from the default):** `false`
+From //BUILD.gn:14
-From //third_party/dart/runtime/runtime_args.gni:39
+**Current value for `target_cpu = "x64"`:** `["//garnet/packages/config:kernel_crash_checker", "//garnet/packages/prod:crashpad_agent", "//garnet/packages/prod:feedback_agent", "//garnet/packages/prod:kernel_crash_checker", "//garnet/packages/products:base", "//bundles:kitchen_sink"]`
-### rust_toolchain_triple_suffix
-Sets the fuchsia toolchain target triple suffix (after arch)
+From //root_build_dir/args.gn:3
-**Current value (from the default):** `"fuchsia"`
+**Overridden from the default:** `[]`
-From //build/rust/config.gni:23
+From //BUILD.gn:14
-### kernel_cmdline_files
-Files containing additional kernel command line arguments to bake into
-the boot image. The contents of these files (in order) come after any
-arguments directly in [`kernel_cmdline_args`](#kernel_cmdline_args).
-These can be GN `//` source pathnames or absolute system pathnames.
+### build_libvulkan_img_rgx
+Targets that will be built as IMG vulkan ICDS.
**Current value (from the default):** `[]`
-From //build/images/BUILD.gn:486
+From //garnet/lib/magma/gnbuild/magma.gni:47
-### max_log_disk_usage
-Controls how many bytes of space on disk are used to persist device logs.
-Should be a string value that only contains digits.
+### debian_guest_earlycon
-**Current value (from the default):** `"0"`
+**Current value (from the default):** `false`
-From //garnet/bin/log_listener/BUILD.gn:13
+From //src/virtualization/packages/debian_guest/BUILD.gn:10
-### skia_android_serial
+### minfs_minimum_inodes
**Current value (from the default):** `""`
-From //third_party/skia/BUILD.gn:41
+From //build/images/fvm.gni:29
-### skia_use_zlib
+### skia_enable_tools
-**Current value (from the default):** `true`
+**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:35
+From //third_party/skia/gn/skia.gni:12
-### blobfs_minimum_data_bytes
-Number of bytes to reserve for data in the fs. This is in addition
-to what is reserved, if any, for the inodes. Data bytes constitutes
-"usable" space of the fs.
-An empty string does not reserve any additional space than minimum
-required for the filesystem.
+### build_libvulkan_arm_mali
+Targets that will be built as mali vulkan ICDS.
-**Current value (from the default):** `""`
+**Current value (from the default):** `[]`
-From //build/images/fvm.gni:36
+From //garnet/lib/magma/gnbuild/magma.gni:38
-### exclude_kernel_service
-Whether the VM includes the kernel service in all modes (debug, release,
-product).
+### data_partition_manifest
+Path to manifest file containing data to place into the initial /data
+partition.
-**Current value (from the default):** `false`
+**Current value (from the default):** `""`
-From //third_party/dart/runtime/runtime_args.gni:88
+From //build/images/BUILD.gn:28
-### skia_use_expat
+### devmgr_config
+List of arguments to add to /boot/config/devmgr.
+These come after synthesized arguments to configure blobfs and pkgfs.
-**Current value for `target_cpu = "arm64"`:** `false`
+**Current value (from the default):** `[]`
-From //.gn:27
+From //build/images/BUILD.gn:475
-**Overridden from the default:** `true`
+### magma_enable_developer_build
+Enable this to have the msd include a suite of tests and invoke them
+automatically when the driver starts.
-From //third_party/skia/BUILD.gn:23
+**Current value (from the default):** `false`
-**Current value for `target_cpu = "x64"`:** `false`
+From //garnet/lib/magma/gnbuild/magma.gni:21
-From //.gn:27
+### skia_enable_flutter_defines
-**Overridden from the default:** `true`
+**Current value for `target_cpu = "arm64"`:** `true`
-From //third_party/skia/BUILD.gn:23
+From //.gn:24
-### universe_package_labels
-If you add package labels to this variable, the packages will be included
-in the 'universe' package set, which represents all software that is
-produced that is to be published to a package repository or to the SDK by
-the build. The build system ensures that the universe package set includes
-the base and cache package sets, which means you do not need to redundantly
-include those labels in this variable.
+**Overridden from the default:** `false`
-**Current value for `target_cpu = "arm64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
+From //third_party/skia/BUILD.gn:17
-From //products/core.gni:27
+**Current value for `target_cpu = "x64"`:** `true`
-**Overridden from the default:** `[]`
+From //.gn:24
-From //BUILD.gn:30
+**Overridden from the default:** `false`
-**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
+From //third_party/skia/BUILD.gn:17
-From //products/core.gni:27
+### board_package_labels
+A list of package labels to include in the 'base' package set. Used by the
+board definition rather than the product definition.
+
+**Current value for `target_cpu = "arm64"`:** `["//garnet/packages/prod:drivers", "//garnet/packages/prod:sysmem-assistant"]`
+
+From //boards/arm64.gni:11
**Overridden from the default:** `[]`
-From //BUILD.gn:30
+From //BUILD.gn:34
-### zircon_extra_args
-[Zircon GN build arguments](../../../zircon/docs/gen/build_arguments.md).
-This is included in the default value of [`zircon_args`](#zircon_args) so
-you can set this to add things there without wiping out the defaults.
-When you set `zircon_args` directly, then this has no effect at all.
-Arguments you set here override any arguments in the default
-`zircon_args`. There is no way to append to a value from the defaults.
-Note that for just setting simple (string-only) values in Zircon GN's
-[`variants`](../../../zircon/docs/gen/build_arguments.md#variants), the
-default [`zircon_args`](#zircon_args) uses a `variants` value derived from
-[`select_variant`](#select_variant) so for simple cases there is no need
-to explicitly set Zircon's `variants` here.
+**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:drivers"]`
-**Current value (from the default):** `{ }`
+From //boards/x64.gni:13
-From //build/config/fuchsia/zircon.gni:27
+**Overridden from the default:** `[]`
-### dart_space_dart
-Whether experimental space dart mode is enabled for Dart applications.
+From //BUILD.gn:34
+
+### dart_debug
+Instead of using is_debug, we introduce a different flag for specifying a
+Debug build of Dart so that clients can still use a Release build of Dart
+while themselves doing a Debug build.
**Current value (from the default):** `false`
-From [//topaz/runtime/dart/dart_component.gni:41](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#41)
+From //third_party/dart/runtime/runtime_args.gni:9
-### fuchsia_vulkan_sdk
-Path to Fuchsia Vulkan SDK
+### enable_sketchy_subsystem
-**Current value (from the default):** `"//third_party/vulkan_loader_and_validation_layers"`
+**Current value (from the default):** `false`
-From //build/vulkan/config.gni:10
+From //garnet/bin/ui/scenic/BUILD.gn:13
-### have_secmem_ta
-The secmem TA must be obtained elsewhere and put into the firmware
-directory.
+### zedboot_cmdline_files
+Files containing additional kernel command line arguments to bake into
+the Zedboot image. The contents of these files (in order) come after any
+arguments directly in [`zedboot_cmdline_args`](#zedboot_cmdline_args).
+These can be GN `//` source pathnames or absolute system pathnames.
-**Current value (from the default):** `false`
+**Current value (from the default):** `[]`
-From //garnet/bin/sysmem-assistant/BUILD.gn:44
+From //build/images/zedboot/BUILD.gn:23
-### skia_use_egl
+### enable_value_subsystem
**Current value (from the default):** `false`
-From //third_party/skia/BUILD.gn:22
+From //garnet/bin/ui/scenic/BUILD.gn:11
-### use_prebuilt_dart_sdk
-Whether to use the prebuilt Dart SDK for everything.
-When setting this to false, the preubilt Dart SDK will not be used in
-situations where the version of the SDK matters, but may still be used as an
-optimization where the version does not matter.
+### fvm_image_size
+The size in bytes of the FVM partition image to create. Normally this is
+computed to be just large enough to fit the blob and data images. The
+default value is "", which means to size based on inputs. Specifying a size
+that is too small will result in build failure.
-**Current value (from the default):** `true`
+**Current value (from the default):** `""`
-From //build/dart/dart.gni:15
+From //build/images/fvm.gni:12
-### zircon_b_partition
+### skia_use_lua
-**Current value (from the default):** `""`
+**Current value (from the default):** `false`
-From //build/images/BUILD.gn:40
+From //third_party/skia/BUILD.gn:31
-### dart_version_git_info
-Whether the Dart binary version string should include the git hash and
-git commit time.
+### dart_snapshot_kind
-**Current value (from the default):** `true`
+**Current value (from the default):** `"kernel"`
-From //third_party/dart/runtime/runtime_args.gni:60
+From //third_party/dart/utils/application_snapshot.gni:14
-### debian_guest_earlycon
+### skia_enable_fontmgr_custom
**Current value (from the default):** `false`
-From //src/virtualization/packages/debian_guest/BUILD.gn:10
+From //third_party/skia/BUILD.gn:68
-### linux_guest_extras_path
+### dart_use_crashpad
+Whether to link Crashpad library for crash handling. Only supported on
+Windows for now.
-**Current value (from the default):** `""`
+**Current value (from the default):** `false`
-From //src/virtualization/packages/linux_guest/BUILD.gn:13
+From //third_party/dart/runtime/runtime_args.gni:51
-### skia_enable_spirv_validation
+### fuchsia_use_vulkan
+Consolidated build toggle for use of Vulkan across Fuchsia
-**Current value (from the default):** `false`
+**Current value (from the default):** `true`
-From //third_party/skia/BUILD.gn:47
+From //build/vulkan/config.gni:7
-### clang_lib_dir
-Path to Clang lib directory.
+### skia_use_vulkan
-**Current value (from the default):** `"../build/buildtools/linux-x64/clang/lib"`
+**Current value (from the default):** `true`
-From //build/images/manifest.gni:19
+From //third_party/skia/BUILD.gn:86
-### extra_authorized_keys_file
-Additional SSH authorized_keys file to include in the build.
-For example:
- extra_authorized_keys_file=\"$HOME/.ssh/id_rsa.pub\"
+### auto_login_to_guest
+Whether basemgr should automatically login as a persistent guest user.
-**Current value (from the default):** `""`
+**Current value (from the default):** `false`
-From [//third_party/openssh-portable/fuchsia/developer-keys/BUILD.gn:11](https://fuchsia.googlesource.com/third_party/openssh-portable/+/62f4ca0d82fa50a3405703837031a15c36dccdd4/fuchsia/developer-keys/BUILD.gn#11)
+From //peridot/bin/basemgr/BUILD.gn:13
-### vbmeta_b_partition
+### build_info_product
+Product configuration of the current build
**Current value (from the default):** `""`
-From //build/images/BUILD.gn:43
+From //garnet/BUILD.gn:21
-### warn_on_sdk_changes
-Whether to only warn when an SDK has been modified.
-If false, any unacknowledged SDK change will cause a build failure.
+### concurrent_go_jobs
+Maximum number of Go processes to run in parallel.
-**Current value (from the default):** `false`
+**Current value (from the default):** `16`
-From //build/sdk/config.gni:8
+From //build/go/BUILD.gn:11
-### expat_build_root
+### skia_use_expat
-**Current value (from the default):** `"//third_party/expat"`
+**Current value for `target_cpu = "arm64"`:** `false`
-From //garnet/lib/magma/gnbuild/magma.gni:9
+From //.gn:27
-### use_goma
-Set to true to enable distributed compilation using Goma.
+**Overridden from the default:** `true`
-**Current value (from the default):** `false`
+From //third_party/skia/BUILD.gn:23
-From //build/toolchain/goma.gni:9
+**Current value for `target_cpu = "x64"`:** `false`
-### always_zedboot
-Build boot images that prefer Zedboot over local boot (only for EFI).
+From //.gn:27
-**Current value (from the default):** `false`
+**Overridden from the default:** `true`
-From //build/images/BUILD.gn:809
+From //third_party/skia/BUILD.gn:23
-### skia_use_wuffs
+### thinlto_jobs
+Number of parallel ThinLTO jobs.
-**Current value (from the default):** `false`
+**Current value (from the default):** `8`
-From //third_party/skia/BUILD.gn:34
+From //build/config/lto/config.gni:13
-### fvm_slice_size
-The size of the FVM partition images "slice size". The FVM slice size is a
-minimum size of a particular chunk of a partition that is stored within
-FVM. A very small slice size may lead to decreased throughput. A very large
-slice size may lead to wasted space. The selected default size of 8mb is
-selected for conservation of space, rather than performance.
+### build_libvulkan_vsl_gc
+Targets that will be built as verisilicon vulkan ICDS.
-**Current value (from the default):** `"8388608"`
+**Current value (from the default):** `[]`
-From //build/images/fvm.gni:19
+From //garnet/lib/magma/gnbuild/magma.gni:41
-### skia_version
+### linux_runner_ip
+Default values for the guest network configuration.
-**Current value (from the default):** `""`
+These are currently hard-coded to match what is setup in the virtio-net
+device.
-From //third_party/flutter/shell/version/version.gni:8
+See //src/virtualization/bin/vmm/device/virtio_net.cc for more details.
-### build_info_board
-Board configuration of the current build
+**Current value (from the default):** `"10.0.0.2"`
-**Current value (from the default):** `"qemu-arm64"`
+From //src/virtualization/packages/biscotti_guest/linux_runner/BUILD.gn:17
-From //garnet/BUILD.gn:24
+### sdk_id
+Identifier for the Core SDK.
-### dart_custom_version_for_pub
-When this argument is a non-empty string, the version repoted by the
-Dart VM will be one that is compatible with pub's interpretation of
-semantic version strings. The version string will also include the values
-of the argument. In particular the version string will read:
+**Current value (from the default):** `""`
- "M.m.p-dev.x.x-$(dart_custom_version_for_pub)-$(short_git_hash)"
+From //sdk/config.gni:7
-Where 'M', 'm', and 'p' are the major, minor and patch version numbers,
-and 'dev.x.x' is the dev version tag most recently preceeding the current
-revision. The short git hash can be omitted by setting
-dart_version_git_info=false
+### zircon_args
+[Zircon GN build arguments](../../../zircon/docs/gen/build_arguments.md).
+The default passes through GOMA settings and
+[`select_variant`](#select_variant) shorthand selectors.
+**Only set this if you want to wipe out all the defaults that
+propagate from Fuchsia GN to Zircon GN.** The default value
+folds in [`zircon_extra_args`](#zircon_extra_args), so usually
+it's better to just set `zircon_extra_args` and leave `zircon_args` alone.
+Any individual Zircon build argument set in `zircon_extra_args` will
+silently clobber the default value shown here.
-**Current value (from the default):** `""`
+**Current value (from the default):**
+```
+{
+ default_deps = [":legacy-arm64"]
+ enable_kernel_debugging_features = false
+ enable_netsvc_debugging_features = false
+ goma_dir = "/home/swarming/goma"
+ use_goma = false
+ variants = []
+}
+```
-From //third_party/dart/runtime/runtime_args.gni:73
+From //build/config/fuchsia/zircon.gni:46
-### create_kernel_service_snapshot
+### dart_target_arch
+Explicitly set the target architecture to use a simulator.
+Available options are: arm, arm64, x64, ia32, and dbc.
-**Current value (from the default):** `false`
+**Current value (from the default):** `"arm64"`
-From //third_party/dart/runtime/runtime_args.gni:101
+From //third_party/dart/runtime/runtime_args.gni:32
-### dart_debug_optimization_level
-The optimization level to use for debug builds. Defaults to 0 for builds with
-code coverage enabled.
+### skia_llvm_lib
-**Current value (from the default):** `"2"`
+**Current value (from the default):** `"LLVM"`
-From //third_party/dart/runtime/runtime_args.gni:36
+From //third_party/skia/BUILD.gn:58
-### msd_arm_enable_all_cores
-Enable all 8 cores, which is faster but emits more heat.
+### skia_use_sfntly
-**Current value (from the default):** `true`
+**Current value for `target_cpu = "arm64"`:** `false`
-From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:9
+From //.gn:30
-### skia_enable_skshaper
+**Overridden from the default:** `false`
-**Current value (from the default):** `true`
+From //third_party/skia/BUILD.gn:64
-From //third_party/skia/modules/skshaper/BUILD.gn:9
+**Current value for `target_cpu = "x64"`:** `false`
-### concurrent_go_jobs
-Maximum number of Go processes to run in parallel.
+From //.gn:30
-**Current value (from the default):** `16`
+**Overridden from the default:** `false`
-From //build/go/BUILD.gn:11
+From //third_party/skia/BUILD.gn:64
-### debian_guest_qcow
-Package the rootfs as a QCOW image (as opposed to a flat file).
+### framework_packages
-**Current value (from the default):** `true`
+**Current value (from the default):** `["collection", "flutter", "meta", "typed_data", "vector_math"]`
-From //src/virtualization/packages/debian_guest/BUILD.gn:9
+From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:8](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/flutter_runner/prebuilt_framework.gni#8)
-### enable_gfx_subsystem
+### skia_enable_fontmgr_fuchsia
**Current value (from the default):** `true`
-From //garnet/bin/ui/scenic/BUILD.gn:12
+From //third_party/skia/BUILD.gn:71
-### host_os
+### skia_generate_workarounds
-**Current value (from the default):** `"linux"`
+**Current value (from the default):** `false`
-### prebuilt_dart_sdk
-Directory containing prebuilt Dart SDK.
-This must have in its `bin/` subdirectory `gen_snapshot.OS-CPU` binaries.
-Set to empty for a local build.
+From //third_party/skia/BUILD.gn:52
-**Current value (from the default):** `"//topaz/tools/prebuilt-dart-sdk/linux-x64"`
+### magma_enable_tracing
+Enable this to include fuchsia tracing capability
-From //build/dart/dart.gni:9
+**Current value (from the default):** `true`
-### skia_enable_fontmgr_custom_empty
+From //garnet/lib/magma/gnbuild/magma.gni:17
-**Current value (from the default):** `false`
+### skia_use_wuffs
-From //third_party/skia/BUILD.gn:69
+**Current value (from the default):** `false`
-### skia_qt_path
+From //third_party/skia/BUILD.gn:34
-**Current value (from the default):** `""`
+### log_startup_sleep
-From //third_party/skia/BUILD.gn:50
+**Current value (from the default):** `"30000"`
-### concurrent_link_jobs
-Maximum number of concurrent link jobs.
+From //garnet/bin/log_listener/BUILD.gn:14
-We often want to run fewer links at once than we do compiles, because
-linking is memory-intensive. The default to use varies by platform and by
-the amount of memory available, so we call out to a script to get the right
-value.
+### skia_enable_ccpr
-**Current value (from the default):** `16`
+**Current value (from the default):** `true`
-From //build/toolchain/BUILD.gn:15
+From //third_party/skia/BUILD.gn:42
-### dart_platform_bytecode
-Whether the VM's platform dill file contains bytecode.
+### skia_use_egl
**Current value (from the default):** `false`
-From //third_party/dart/runtime/runtime_args.gni:84
-
-### sdk_dirs
-The directories to search for parts of the SDK.
+From //third_party/skia/BUILD.gn:22
-By default, we search the public directories for the various layers.
-In the future, we'll search a pre-built SDK as well.
+### zircon_enable_kernel_debugging_features
+Whether to include various features (non-shipping, insecure, etc.) in the
+kernel or netsvc builds.
-**Current value (from the default):** `["//garnet/public", "//peridot/public", "//topaz/public"]`
+**Current value for `target_cpu = "arm64"`:** `false`
-From //build/config/fuchsia/sdk.gni:10
+From //products/core.gni:9
-### vbmeta_a_partition
+**Overridden from the default:** `false`
-**Current value (from the default):** `""`
+From //build/config/fuchsia/zircon.gni:32
-From //build/images/BUILD.gn:42
+**Current value for `target_cpu = "x64"`:** `false`
-### auto_update_packages
-Whether the component loader should automatically update packages.
+From //products/core.gni:9
-**Current value (from the default):** `true`
+**Overridden from the default:** `false`
-From //garnet/bin/sysmgr/BUILD.gn:10
+From //build/config/fuchsia/zircon.gni:32
-### build_info_version
-Logical version of the current build. If not set, defaults to the timestamp
-of the most recent update.
+### current_os
**Current value (from the default):** `""`
-From //garnet/BUILD.gn:28
-
-### gocache_dir
- gocache_dir
- Directory GOCACHE environment variable will be set to. This directory
- will have build and test results cached, and is safe to be written to
- concurrently. If overridden, this directory must be a full path.
-
-**Current value (from the default):** `"/b/s/w/ir/k/root_build_dir/host_x64/.gocache"`
+### dart_default_app
+Controls whether dart_app() targets generate JIT or AOT Dart snapshots.
+This defaults to JIT, use `fx set <ARCH> --args
+'dart_default_app="dart_aot_app"' to switch to AOT.
-From //build/go/go_build.gni:16
+**Current value (from the default):** `"dart_jit_app"`
-### board_package_labels
-A list of package labels to include in the 'base' package set. Used by the
-board definition rather than the product definition.
+From [//topaz/runtime/dart/dart_component.gni:19](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/dart/dart_component.gni#19)
-**Current value for `target_cpu = "arm64"`:** `["//garnet/packages/prod:drivers", "//garnet/packages/prod:sysmem-assistant"]`
+### kernel_cmdline_files
+Files containing additional kernel command line arguments to bake into
+the boot image. The contents of these files (in order) come after any
+arguments directly in [`kernel_cmdline_args`](#kernel_cmdline_args).
+These can be GN `//` source pathnames or absolute system pathnames.
-From //boards/arm64.gni:11
+**Current value (from the default):** `[]`
-**Overridden from the default:** `[]`
+From //build/images/BUILD.gn:486
-From //BUILD.gn:34
+### auto_update_packages
+Whether the component loader should automatically update packages.
-**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:drivers"]`
+**Current value (from the default):** `true`
-From //boards/x64.gni:13
+From //garnet/bin/sysmgr/BUILD.gn:10
-**Overridden from the default:** `[]`
+### dart_use_tcmalloc
+Whether to link the standalone VM against tcmalloc. The standalone build of
+the VM enables this only for Linux builds.
-From //BUILD.gn:34
+**Current value (from the default):** `false`
-### build_sdk_archives
-Whether to build SDK tarballs.
+From //third_party/dart/runtime/runtime_args.gni:47
-**Current value (from the default):** `false`
+### prebuilt_libvulkan_arm_path
-From //build/sdk/sdk.gni:13
+**Current value (from the default):** `""`
-### skia_pdf_subset_harfbuzz
-TODO: set skia_pdf_subset_harfbuzz to skia_use_harfbuzz.
+From //garnet/lib/magma/gnbuild/magma.gni:23
-**Current value (from the default):** `false`
+### max_log_disk_usage
+Controls how many bytes of space on disk are used to persist device logs.
+Should be a string value that only contains digits.
-From //third_party/skia/gn/skia.gni:18
+**Current value (from the default):** `"0"`
-### current_cpu
+From //garnet/bin/log_listener/BUILD.gn:13
-**Current value (from the default):** `""`
+### target_cpu
-### experimental_wlan_client_mlme
-Selects the SoftMAC client implementation to use. Choices:
- false (default) - C++ Client MLME implementation
- true - Rust Client MLME implementation
-This argument is temporary until Rust MLME is ready to be used.
+**Current value for `target_cpu = "arm64"`:** `"arm64"`
-**Current value (from the default):** `false`
+From //boards/arm64.gni:5
-From //src/connectivity/wlan/lib/mlme/cpp/BUILD.gn:10
+**Overridden from the default:** `""`
-### max_fvm_size
-Maximum allowable size for the FVM in a release mode build
-Zero means no limit
+**Current value for `target_cpu = "x64"`:** `"x64"`
-**Current value (from the default):** `"0"`
+From //boards/x64.gni:5
-From //build/images/max_fvm_size.gni:8
+**Overridden from the default:** `""`
-### crash_diagnostics_dir
-Clang crash reports directory path. Use empty path to disable altogether.
+### universal_variants
-**Current value (from the default):** `"//root_build_dir/clang-crashreports"`
+**Current value (from the default):**
+```
+[{
+ configs = []
+ name = "release"
+ toolchain_args = {
+ is_debug = false
+}
+}]
+```
-From //build/config/BUILD.gn:9
+From //build/config/BUILDCONFIG.gn:423
-### crashpad_dependencies
+### use_mock_magma
-**Current value (from the default):** `"fuchsia"`
+**Current value (from the default):** `false`
-From [//third_party/crashpad/build/crashpad_buildconfig.gni:22](https://chromium.googlesource.com/crashpad/crashpad/+/d221b7cadab5f00c6999f060a5bcb0896e25c7b7/build/crashpad_buildconfig.gni#22)
+From [//third_party/mesa/src/intel/vulkan/BUILD.gn:25](https://fuchsia.googlesource.com/third_party/mesa/+/232bf12b10899d335a3fe69d947a738541ace7d3/src/intel/vulkan/BUILD.gn#25)
-### prebuilt_framework_name
+### vbmeta_r_partition
**Current value (from the default):** `""`
-From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:7](https://fuchsia.googlesource.com/topaz/+/e815667d2e8f06051f242e52f04785428bd8e743/runtime/flutter_runner/prebuilt_framework.gni#7)
-
-### skia_use_fontconfig
+From //build/images/BUILD.gn:44
-**Current value for `target_cpu = "arm64"`:** `false`
+### concurrent_rust_jobs
+Maximum number of Rust processes to run in parallel.
-From //.gn:28
+We run multiple rustc jobs in parallel, each of which can cause significant
+amount of memory, especially when using LTO. To avoid out-of-memory errors
+we explicitly reduce the number of jobs.
-**Overridden from the default:** `true`
+**Current value (from the default):** `14`
-From //third_party/skia/BUILD.gn:24
+From //build/rust/BUILD.gn:15
-**Current value for `target_cpu = "x64"`:** `false`
+### exclude_kernel_service
+Whether the VM includes the kernel service in all modes (debug, release,
+product).
-From //.gn:28
+**Current value (from the default):** `false`
-**Overridden from the default:** `true`
+From //third_party/dart/runtime/runtime_args.gni:88
-From //third_party/skia/BUILD.gn:24
+### toolchain_variant
+*This should never be set as a build argument.*
+It exists only to be set in `toolchain_args`.
+See //build/toolchain/clang_toolchain.gni for details.
+This variable is a scope giving details about the current toolchain:
+ `toolchain_variant.base`
+ [label] The "base" toolchain for this variant, *often the
+ right thing to use in comparisons, not `current_toolchain`.*
+ This is the toolchain actually referenced directly in GN
+ source code. If the current toolchain is not
+ `shlib_toolchain` or a variant toolchain, this is the same
+ as `current_toolchain`. In one of those derivative
+ toolchains, this is the toolchain the GN code probably
+ thought it was in. This is the right thing to use in a test
+ like `toolchain_variant.base == target_toolchain`, rather
+ rather than comparing against `current_toolchain`.
+ `toolchain_variant.name`
+ [string] The name of this variant, as used in `variant` fields
+ in [`select_variant`](#select_variant) clauses. In the base
+ toolchain and its `shlib_toolchain`, this is `""`.
+ `toolchain_variant.suffix`
+ [string] This is "-${toolchain_variant.name}", "" if name is empty.
+ `toolchain_variant.is_pic_default`
+ [bool] This is true in `shlib_toolchain`.
+The other fields are the variant's effects as defined in
+[`known_variants`](#known_variants).
-### target_os
+**Current value (from the default):**
+```
+{
+ base = "//build/toolchain/fuchsia:arm64"
+}
+```
-**Current value (from the default):** `""`
+From //build/config/BUILDCONFIG.gn:74
### cache_package_labels
If you add package labels to this variable, the packages will be included
@@ -2305,77 +2357,20 @@ From //products/core.gni:25
From //BUILD.gn:22
-### dart_snapshot_kind
-
-**Current value (from the default):** `"kernel"`
-
-From //third_party/dart/utils/application_snapshot.gni:14
-
-### fuchsia_use_vulkan
-Consolidated build toggle for use of Vulkan across Fuchsia
-
-**Current value (from the default):** `true`
-
-From //build/vulkan/config.gni:7
-
-### persist_logs
-
-**Current value (from the default):** `true`
-
-From //build/persist_logs.gni:13
-
-### skia_gl_standard
-
-**Current value (from the default):** `""`
-
-From //third_party/skia/BUILD.gn:80
-
-### skia_use_libheif
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:37
-
-### use_vbmeta
-If true, then the paving script will pave vbmeta images to the target device.
-It is assumed that the vbmeta image will be created by the custom_signing_script.
+### shell_enable_vulkan
**Current value (from the default):** `false`
-From //build/images/custom_signing.gni:16
-
-### zircon_build_root
-
-**Current value (from the default):** `"//zircon"`
-
-From //garnet/lib/magma/gnbuild/magma.gni:12
-
-### blobfs_minimum_inodes
-minimum_inodes is the number of inodes to reserve for the fs
-An empty string does not reserve any additional space than minimum
-required for the filesystem.
-
-**Current value (from the default):** `""`
-
-From //build/images/fvm.gni:28
+From //third_party/flutter/shell/config.gni:6
-### crashpad_use_boringssl_for_http_transport_socket
-TODO(scottmg): https://crbug.com/crashpad/266 fuchsia:DX-690: BoringSSL
-was removed from the Fuchsia SDK. Re-enable it when we have a way to acquire
-a BoringSSL lib again.
+### skia_skqp_global_error_tolerance
-**Current value (from the default):** `true`
+**Current value (from the default):** `0`
-From [//third_party/crashpad/util/net/tls.gni:21](https://chromium.googlesource.com/crashpad/crashpad/+/d221b7cadab5f00c6999f060a5bcb0896e25c7b7/util/net/tls.gni#21)
+From //third_party/skia/BUILD.gn:55
## `target_cpu = "arm64"`
-### amlogic_decoder_tests
-
-**Current value (from the default):** `false`
-
-From //garnet/drivers/video/amlogic-decoder/BUILD.gn:11
-
### arm_float_abi
The ARM floating point mode. This is either the string "hard", "soft", or
"softfp". An empty string means to use the default one for the
@@ -2414,6 +2409,12 @@ From //build/config/arm.gni:28
From //build/config/arm.gni:12
+### amlogic_decoder_tests
+
+**Current value (from the default):** `false`
+
+From //garnet/drivers/video/amlogic-decoder/BUILD.gn:11
+
## `target_cpu = "x64"`
### msd_intel_enable_mapping_cache
diff --git a/zircon/docs/gen/build_arguments.md b/zircon/docs/gen/build_arguments.md
index aabb41ca764c53f1242125f04bbabb557b2ab4d4..49ef4fa4fef7308262516e5fc67446ec16a43b98 100644
--- a/zircon/docs/gen/build_arguments.md
+++ b/zircon/docs/gen/build_arguments.md
@@ -2,18 +2,13 @@
## All builds
-### asan_default_options
-Default [AddressSanitizer](https://llvm.org/docs/AddressSanitizer.html)
-options (before the `ASAN_OPTIONS` environment variable is read at
-runtime). This can be set as a build argument to affect most "asan"
-variants in $variants (which see), or overridden in $toolchain_args in
-one of those variants. Note that setting this nonempty may conflict
-with programs that define their own `__asan_default_options` C
-function.
+### enable_kernel_debugging_features
+Whether to include various features (non-shipping, insecure, etc.) in the
+kernel or netsvc builds.
-**Current value (from the default):** `""`
+**Current value (from the default):** `false`
-From //public/gn/config/instrumentation/BUILD.gn:15
+From //public/gn/config/product_parameters.gni:12
### symbol_level
* 0 means no debugging information.
@@ -24,23 +19,36 @@ From //public/gn/config/instrumentation/BUILD.gn:15
From //public/gn/config/levels.gni:20
-### thinlto_cache_dir
-ThinLTO cache directory path.
+### zx
+*This must never be set as a build argument*.
+
+"$zx/" is the prefix for GN "source-absolute" paths in the Zircon
+build. When Zircon is built standalone, the Zircon repository is the
+root of the build (where `.gn` is found) so "$zx/" becomes "//". When
+Zircon is part of a larger unified build, there is a higher-level `.gn`
+file that uses `default_args` to set "$zx/" to "//zircon/".
-**Current value (from the default):** `"user-arm64-thinlto.shlib/thinlto-cache"`
+**Current value (from the default):** `"/"`
-From //public/gn/config/lto/BUILD.gn:22
+From //public/gn/BUILDCONFIG.gn:13
-### build_id_dir
-Directory to populate with `xx/yyy` and `xx/yyy.debug` links to ELF
-files. For every ELF binary built, with build ID `xxyyy` (lowercase
-hexadecimal of any length), `xx/yyy` is a hard link to the stripped
-file and `xx/yyy.debug` is a hard link to the unstripped file.
-Symbolization tools and debuggers find symbolic information this way.
+### enable_acpi_debug
+Enable debug output in the ACPI library (used by the ACPI bus driver).
-**Current value (from the default):** `"/b/s/w/ir/k/out/build-zircon/.build-id"`
+**Current value (from the default):** `false`
-From //public/gn/toolchain/c_toolchain.gni:17
+From //third_party/lib/acpica/BUILD.gn:9
+
+### default_deps
+Defines the `//:default` target: what `ninja` with no arguments does.
+
+**Current value (from the default):** `[":build-tests", ":ids", ":images", ":tools"]`
+
+From //BUILD.gn:19
+
+### host_os
+
+**Current value (from the default):** `"linux"`
### kernel_version_string
Version string embedded in the kernel for `zx_system_get_version`.
@@ -51,34 +59,40 @@ Zircon git revision of the checkout.
From //kernel/lib/version/BUILD.gn:9
-### use_prebuilt_gcc
-If $gcc_tool_dir is "", then this controls how the GCC toolchain
-binaries are found. If true, the standard prebuilt is used. If false,
-the tools are just expected to be found in PATH.
+### opt_level
+* -1 means really unoptimized (-O0), usually only build-tested and not run.
+* 0 means "optimized for debugging" (-Og), light enough to avoid confusion.
+ 1, 2, and 3 are increasing levels of optimization.
+* 4 is optimized for space rather than purely for speed.
-**Current value (from the default):** `true`
+**Current value (from the default):** `2`
-From //public/gn/toolchain/gcc.gni:9
+From //public/gn/config/levels.gni:15
-### current_cpu
+### use_prebuilt_clang
+If $clang_tool_dir is "", then this controls how the Clang toolchain
+binaries are found. If true, then the standard prebuilt is used.
+Otherwise the tools are just expected to be found by the shell via `PATH`.
-**Current value (from the default):** `""`
+**Current value (from the default):** `true`
-### current_os
+From //public/gn/toolchain/clang.gni:9
-**Current value (from the default):** `""`
+### use_prebuilt_gcc
+If $gcc_tool_dir is "", then this controls how the GCC toolchain
+binaries are found. If true, the standard prebuilt is used. If false,
+the tools are just expected to be found in PATH.
-### enable_kernel_debugging_features
-Whether to include various features (non-shipping, insecure, etc.) in the
-kernel or netsvc builds.
+**Current value (from the default):** `true`
-**Current value (from the default):** `false`
+From //public/gn/toolchain/gcc.gni:9
-From //public/gn/config/product_parameters.gni:12
+### crash_diagnostics_dir
+Clang crash reports directory path. Use empty path to disable altogether.
-### host_cpu
+**Current value (from the default):** `"/b/s/w/ir/k/out/build-zircon/clang-crashreports"`
-**Current value (from the default):** `"x64"`
+From //public/gn/config/BUILD.gn:11
### clang_tool_dir
Directory where the Clang toolchain binaries ("clang", "llvm-nm", etc.) are
@@ -89,30 +103,25 @@ This toolchain is expected to support both Fuchsia targets and the host.
From //public/gn/toolchain/clang.gni:14
-### enable_netsvc_debugging_features
+### detailed_scheduler_tracing
+Enable detailed scheduler traces.
**Current value (from the default):** `false`
-From //public/gn/config/product_parameters.gni:13
-
-### enable_user_pci
-Enable userspace PCI and disable kernel PCI.
-
-**Current value (from the default):** `false`
+From //kernel/params.gni:39
-From //kernel/params.gni:42
+### goma_dir
+Absolute directory containing the Goma source code.
-### target_os
+**Current value (from the default):** `"/home/swarming/goma"`
-**Current value (from the default):** `""`
+From //public/gn/toolchain/goma.gni:12
-### kernel_extra_defines
-Extra macro definitions for kernel code, e.g. "DISABLE_KASLR",
-"ENABLE_KERNEL_LL_DEBUG".
+### kernel_base
-**Current value (from the default):** `[]`
+**Current value (from the default):** `"0xffffffff00000000"`
-From //kernel/params.gni:46
+From //kernel/params.gni:18
### malloc
@@ -120,12 +129,25 @@ From //kernel/params.gni:46
From //third_party/ulib/musl/BUILD.gn:6
-### smp_max_cpus
-Maximum number of CPUs the kernel will run on (others will be ignored).
+### use_ccache
+Set to true to enable compiling with ccache.
+
+**Current value (from the default):** `false`
+
+From //public/gn/toolchain/ccache.gni:9
+
+### asan_default_options
+Default [AddressSanitizer](https://llvm.org/docs/AddressSanitizer.html)
+options (before the `ASAN_OPTIONS` environment variable is read at
+runtime). This can be set as a build argument to affect most "asan"
+variants in $variants (which see), or overridden in $toolchain_args in
+one of those variants. Note that setting this nonempty may conflict
+with programs that define their own `__asan_default_options` C
+function.
-**Current value (from the default):** `32`
+**Current value (from the default):** `""`
-From //kernel/params.gni:7
+From //public/gn/config/instrumentation/BUILD.gn:15
### assert_level
* 0 means no assertions, not even standard C `assert()`.
@@ -136,48 +158,29 @@ From //kernel/params.gni:7
From //public/gn/config/levels.gni:9
-### enable_acpi_debug
-Enable debug output in the ACPI library (used by the ACPI bus driver).
+### enable_user_pci
+Enable userspace PCI and disable kernel PCI.
**Current value (from the default):** `false`
-From //third_party/lib/acpica/BUILD.gn:9
-
-### enable_lock_dep
-Enable kernel lock dependency tracking.
-
-**Current value (from the default):** `false`
+From //kernel/params.gni:42
-From //kernel/params.gni:32
+### kernel_aspace_base
-### host_os
+**Current value (from the default):** `"0xffff000000000000"`
-**Current value (from the default):** `"linux"`
+From //kernel/params.gni:26
-### opt_level
-* -1 means really unoptimized (-O0), usually only build-tested and not run.
-* 0 means "optimized for debugging" (-Og), light enough to avoid confusion.
- 1, 2, and 3 are increasing levels of optimization.
-* 4 is optimized for space rather than purely for speed.
+### smp_max_cpus
-**Current value (from the default):** `2`
+**Current value (from the default):** `16`
-From //public/gn/config/levels.gni:15
+From //kernel/params.gni:10
### target_cpu
**Current value (from the default):** `""`
-### tests_in_image
-Whether to include all the Zircon tests in the main standalone ZBI.
-TODO(mcgrathr): This will be replaced by a more sophisticated plan for
-what images to build rather than a single "everything" image that needs
-to be pared down.
-
-**Current value (from the default):** `true`
-
-From //BUILD.gn:16
-
### toolchain
*This must never be set as a build argument.*
It exists only to be set via c_toolchain().
@@ -195,19 +198,23 @@ See environment() for more information.
From //public/gn/BUILDCONFIG.gn:20
-### default_deps
-Defines the `//:default` target: what `ninja` with no arguments does.
+### use_goma
+Set to true to enable distributed compilation using Goma.
-**Current value (from the default):** `[":build-tests", ":ids", ":images", ":tools"]`
+**Current value (from the default):** `false`
-From //BUILD.gn:19
+From //public/gn/toolchain/goma.gni:9
-### detailed_scheduler_tracing
-Enable detailed scheduler traces.
+### build_id_dir
+Directory to populate with `xx/yyy` and `xx/yyy.debug` links to ELF
+files. For every ELF binary built, with build ID `xxyyy` (lowercase
+hexadecimal of any length), `xx/yyy` is a hard link to the stripped
+file and `xx/yyy.debug` is a hard link to the unstripped file.
+Symbolization tools and debuggers find symbolic information this way.
-**Current value (from the default):** `false`
+**Current value (from the default):** `"/b/s/w/ir/k/out/build-zircon/.build-id"`
-From //kernel/params.gni:39
+From //public/gn/toolchain/c_toolchain.gni:17
### enable_fair_scheduler
Disable fair scheduler by default on all architectures.
@@ -217,11 +224,102 @@ ZX-3959: Disable by default until E2E tests stabilize.
From //kernel/params.gni:36
-### kernel_base
+### enable_lock_dep_tests
+Enable kernel lock dependency tracking tests. By default this is
+enabled when tracking is enabled, but can also be eanbled independently
+to assess whether the tests build and *fail correctly* when lockdep is
+disabled.
-**Current value (from the default):** `"0xffffffff80100000"`
+**Current value (from the default):** `false`
+
+From //kernel/params.gni:54
+
+### target_os
+
+**Current value (from the default):** `""`
+
+### thinlto_cache_dir
+ThinLTO cache directory path.
+
+**Current value (from the default):** `"host-arm64-linux-lto/thinlto-cache"`
+
+From //public/gn/config/lto/BUILD.gn:22
+
+### current_cpu
+
+**Current value (from the default):** `""`
+
+### host_cpu
+
+**Current value (from the default):** `"x64"`
+
+### kernel_extra_defines
+Extra macro definitions for kernel code, e.g. "DISABLE_KASLR",
+"ENABLE_KERNEL_LL_DEBUG".
+
+**Current value (from the default):** `[]`
+
+From //kernel/params.gni:46
+
+### sysroot
+The `--sysroot` directory for host compilations.
+This can be a string, which only applies to $host_os-$host_cpu.
+Or it can be a list of scopes containing `cpu`, `os`, and `sysroot`.
+The empty list (or empty string) means don't use `--sysroot` at all.
+
+**Current value (from the default):**
+```
+[{
+ cpu = "arm64"
+ os = "linux"
+ sysroot = "//prebuilt/downloads/sysroot/linux-arm64"
+}, {
+ cpu = "x64"
+ os = "linux"
+ sysroot = "//prebuilt/downloads/sysroot/linux-x64"
+}]
+```
-From //kernel/params.gni:20
+From //public/gn/config/BUILD.gn:17
+
+### tests_in_image
+Whether to include all the Zircon tests in the main standalone ZBI.
+TODO(mcgrathr): This will be replaced by a more sophisticated plan for
+what images to build rather than a single "everything" image that needs
+to be pared down.
+
+**Current value (from the default):** `true`
+
+From //BUILD.gn:16
+
+### thinlto_jobs
+Number of parallel ThinLTO jobs.
+
+**Current value (from the default):** `8`
+
+From //public/gn/config/lto/BUILD.gn:19
+
+### current_os
+
+**Current value (from the default):** `""`
+
+### enable_netsvc_debugging_features
+
+**Current value (from the default):** `false`
+
+From //public/gn/config/product_parameters.gni:13
+
+### gcc_tool_dir
+Directory where the GCC toolchain binaries ("gcc", "nm", etc.) are
+found. If this is "", then the behavior depends on $use_prebuilt_gcc.
+This directory is expected to contain `aarch64-elf-*` and `x86_64-elf-*`
+tools used to build for the Fuchsia targets. This directory will not
+be used for host tools; if GCC is selected for host builds, only the
+system-installed tools found by the shell via `PATH` will be used.
+
+**Current value (from the default):** `""`
+
+From //public/gn/toolchain/gcc.gni:17
### variants
List of "selectors" to request variant builds of certain targets. Each
@@ -445,109 +543,10 @@ Variant scope parameters
From //public/gn/toolchain/variants.gni:222
-### zx
-*This must never be set as a build argument*.
-
-"$zx/" is the prefix for GN "source-absolute" paths in the Zircon
-build. When Zircon is built standalone, the Zircon repository is the
-root of the build (where `.gn` is found) so "$zx/" becomes "//". When
-Zircon is part of a larger unified build, there is a higher-level `.gn`
-file that uses `default_args` to set "$zx/" to "//zircon/".
-
-**Current value (from the default):** `"/"`
-
-From //public/gn/BUILDCONFIG.gn:13
-
-### gcc_tool_dir
-Directory where the GCC toolchain binaries ("gcc", "nm", etc.) are
-found. If this is "", then the behavior depends on $use_prebuilt_gcc.
-This directory is expected to contain `aarch64-elf-*` and `x86_64-elf-*`
-tools used to build for the Fuchsia targets. This directory will not
-be used for host tools; if GCC is selected for host builds, only the
-system-installed tools found by the shell via `PATH` will be used.
-
-**Current value (from the default):** `""`
-
-From //public/gn/toolchain/gcc.gni:17
-
-### kernel_aspace_base
-
-**Current value (from the default):** `"0xffffff8000000000UL"`
-
-From //kernel/params.gni:28
-
-### sysroot
-The `--sysroot` directory for host compilations.
-This can be a string, which only applies to $host_os-$host_cpu.
-Or it can be a list of scopes containing `cpu`, `os`, and `sysroot`.
-The empty list (or empty string) means don't use `--sysroot` at all.
-
-**Current value (from the default):**
-```
-[{
- cpu = "arm64"
- os = "linux"
- sysroot = "//prebuilt/downloads/sysroot/linux-arm64"
-}, {
- cpu = "x64"
- os = "linux"
- sysroot = "//prebuilt/downloads/sysroot/linux-x64"
-}]
-```
-
-From //public/gn/config/BUILD.gn:17
-
-### use_ccache
-Set to true to enable compiling with ccache.
-
-**Current value (from the default):** `false`
-
-From //public/gn/toolchain/ccache.gni:9
-
-### use_goma
-Set to true to enable distributed compilation using Goma.
-
-**Current value (from the default):** `false`
-
-From //public/gn/toolchain/goma.gni:9
-
-### use_prebuilt_clang
-If $clang_tool_dir is "", then this controls how the Clang toolchain
-binaries are found. If true, then the standard prebuilt is used.
-Otherwise the tools are just expected to be found by the shell via `PATH`.
-
-**Current value (from the default):** `true`
-
-From //public/gn/toolchain/clang.gni:9
-
-### crash_diagnostics_dir
-Clang crash reports directory path. Use empty path to disable altogether.
-
-**Current value (from the default):** `"/b/s/w/ir/k/out/build-zircon/clang-crashreports"`
-
-From //public/gn/config/BUILD.gn:11
-
-### enable_lock_dep_tests
-Enable kernel lock dependency tracking tests. By default this is
-enabled when tracking is enabled, but can also be eanbled independently
-to assess whether the tests build and *fail correctly* when lockdep is
-disabled.
+### enable_lock_dep
+Enable kernel lock dependency tracking.
**Current value (from the default):** `false`
-From //kernel/params.gni:54
-
-### goma_dir
-Absolute directory containing the Goma source code.
-
-**Current value (from the default):** `"/home/swarming/goma"`
-
-From //public/gn/toolchain/goma.gni:12
-
-### thinlto_jobs
-Number of parallel ThinLTO jobs.
-
-**Current value (from the default):** `8`
-
-From //public/gn/config/lto/BUILD.gn:19
+From //kernel/params.gni:32