[gndoc] Update GN build arguments documentation Test: CQ Change-Id: Ic91eca3a113e48592f0fa3e0c2d173ea91cabf58

commit: 7cda1faed9042e62f2a18cef71efa0ac1ee3d840 [log] [tgz]
author: docs-roller <docs-roller@fuchsia-infra.iam.gserviceaccount.com> Mon Apr 22 22:37:50 2019 +0000
committer: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> Mon Apr 22 22:37:50 2019 +0000
tree: c842c017ffcd24e146c751aa53f1c1b3d5554b22
parent: 0e0d4b392755eadf00e72ee4ed6ac80c31ffb59a [diff]
diff --git a/docs/gen/build_arguments.md b/docs/gen/build_arguments.md
index 1819d4e..e0e4e9d 100644
--- a/docs/gen/build_arguments.md
+++ b/docs/gen/build_arguments.md

@@ -2,6 +2,116 @@
 
 ## All builds
 
+### 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).
+
+**Current value (from the default):** `"//root_build_dir/tools"`
+
+From //build/host.gni:13
+
+### skia_use_freetype
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:25
+
+### zxcrypt_key_source
+This argument specifies from where the system should obtain the zxcrypt
+master key to the system data partition.
+
+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.
+
+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.
+
+In the future, we may consider adding support for TPMs, or additional logic
+to explicitly support fallback behavior.
+
+**Current value (from the default):** `"null"`
+
+From //build/images/zxcrypt.gni:23
+
+### auto_login_to_guest
+Whether basemgr should automatically login as a persistent guest user.
+
+**Current value (from the default):** `false`
+
+From //peridot/bin/basemgr/BUILD.gn:13
+
+### dart_lib_export_symbols
+Whether libdart should export the symbols of the Dart API.
+
+**Current value (from the default):** `true`
+
+From //third_party/dart/runtime/runtime_args.gni:91
+
+### debian_guest_earlycon
+
+**Current value (from the default):** `false`
+
+From //garnet/bin/guest/pkg/debian_guest/BUILD.gn:10
+
+### enable_gfx_subsystem
+
+**Current value (from the default):** `true`
+
+From //garnet/bin/ui/scenic/BUILD.gn:12
+
+### skia_use_dng_sdk
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //.gn:26
+
+**Overridden from the default:** `false`
+
+From //third_party/skia/BUILD.gn:62
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //.gn:26
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:62
+
+### skia_lex
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:52
+
+### concurrent_dart_jobs
+Maximum number of Dart processes to run in parallel.
+
+Dart analyzer uses a lot of memory which may cause issues when building
+with many parallel jobs e.g. when using goma. To avoid out-of-memory
+errors we explicitly reduce the number of jobs.
+
+**Current value (from the default):** `16`
+
+From //build/dart/BUILD.gn:15
+
+### debian_guest_qcow
+Package the rootfs as a QCOW image (as opposed to a flat file).
+
+**Current value (from the default):** `true`
+
+From //garnet/bin/guest/pkg/debian_guest/BUILD.gn:9
+
 ### linux_runner_extras
 If `true`, the extras.img will be built and mounted inside the container
 at /mnt/chromeos.
@@ -13,12 +123,1371 @@
 
 From //garnet/bin/guest/pkg/biscotti_guest/linux_runner/BUILD.gn:26
 
+### target_sysroot
+The absolute path of the sysroot that is used with the target toolchain.
+
+**Current value (from the default):** `""`
+
+From //build/config/sysroot.gni:7
+
+### universal_variants
+
+**Current value (from the default):**
+```
+[{
+  configs = []
+  name = "release"
+  toolchain_args = {
+  is_debug = false
+}
+}]
+```
+
+From //build/config/BUILDCONFIG.gn:422
+
+### enable_value_subsystem
+
+**Current value (from the default):** `false`
+
+From //garnet/bin/ui/scenic/BUILD.gn:11
+
+### 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/go/go_build.gni:20
+
+### linux_runner_ip
+Default values for the guest network configuration.
+
+These are currently hard-coded to match what is setup in the virtio-net
+device.
+
+See //garnet/bin/guest/vmm/device/virtio_net.cc for more details.
+
+**Current value (from the default):** `"10.0.0.2"`
+
+From //garnet/bin/guest/pkg/biscotti_guest/linux_runner/BUILD.gn:17
+
+### extra_authorized_keys_file
+Additional SSH authorized_keys file to include in the build.
+For example:
+  extra_authorized_keys_file=\"$HOME/.ssh/id_rsa.pub\"
+
+**Current value (from the default):** `""`
+
+From [//third_party/openssh-portable/fuchsia/developer-keys/BUILD.gn:11](https://fuchsia.googlesource.com/third_party/openssh-portable/+/f62e9e1879377736a8505bef9499df060613173d/fuchsia/developer-keys/BUILD.gn#11)
+
+### linux_runner_netmask
+
+**Current value (from the default):** `"255.255.255.0"`
+
+From //garnet/bin/guest/pkg/biscotti_guest/linux_runner/BUILD.gn:19
+
+### host_cpu
+
+**Current value (from the default):** `"x64"`
+
+### dart_custom_version_for_pub
+When this argument is a non-empty string, the version repoted by the
+Dart VM will be one that is compatible with pub's interpretation of
+semantic version strings. The version string will also include the values
+of the argument. In particular the version string will read:
+
+    "M.m.p-dev.x.x-$(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
+
+### extra_variants
+Additional variant toolchain configs to support.
+This is just added to [`known_variants`](#known_variants).
+
+**Current value (from the default):** `[]`
+
+From //build/config/BUILDCONFIG.gn:402
+
+### goma_dir
+Absolute directory containing the Goma source code.
+
+**Current value (from the default):** `"/home/swarming/goma"`
+
+From //build/toolchain/goma.gni:12
+
+### rust_lto
+Sets the default LTO type for rustc bulids.
+
+**Current value (from the default):** `"unset"`
+
+From //build/rust/config.gni:20
+
+### 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):** `"2"`
+
+From //third_party/dart/runtime/runtime_args.gni:36
+
+### dart_use_tcmalloc
+Whether to link the standalone VM against tcmalloc. The standalone build of
+the VM enables this only for Linux builds.
+
+**Current value (from the default):** `false`
+
+From //third_party/dart/runtime/runtime_args.gni:47
+
+### 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/flutter/shell/platform/embedder/embedder.gni:12
+
+### rust_toolchain_triple_suffix
+Sets the fuchsia toolchain target triple suffix (after arch)
+
+**Current value (from the default):** `"fuchsia"`
+
+From //build/rust/config.gni:23
+
+### scenic_enable_vulkan_validation
+Include the vulkan validation layers in scenic.
+
+**Current value (from the default):** `true`
+
+From //garnet/bin/ui/BUILD.gn:40
+
+### minfs_minimum_inodes
+
+**Current value (from the default):** `""`
+
+From //build/images/fvm.gni:29
+
+### msd_arm_enable_all_cores
+Enable all 8 cores, which is faster but emits more heat.
+
+**Current value (from the default):** `true`
+
+From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:9
+
+### prebuilt_framework_path
+
+**Current value (from the default):** `""`
+
+From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:6](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/flutter_runner/prebuilt_framework.gni#6)
+
+### skia_llvm_path
+
+**Current value (from the default):** `""`
+
+From //third_party/skia/BUILD.gn:56
+
+### skia_use_expat
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //.gn:27
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:22
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //.gn:27
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:22
+
+### skia_enable_fontmgr_android
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:69
+
+### skia_use_harfbuzz
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/gn/skia.gni:14
+
+### build_sdk_archives
+Whether to build SDK tarballs.
+
+**Current value (from the default):** `false`
+
+From //build/sdk/sdk.gni:13
+
+### engine_version
+
+**Current value (from the default):** `""`
+
+From //third_party/flutter/shell/version/version.gni:6
+
+### sdk_id
+Identifier for the Core SDK.
+
+**Current value (from the default):** `""`
+
+From //sdk/config.gni:7
+
+### skia_enable_tools
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/gn/skia.gni:12
+
+### skia_use_angle
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:20
+
+### skia_use_icu
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/gn/skia.gni:13
+
+### build_libvulkan_arm_mali
+This is a list of targets that will be built as mali vulkan ICDS.
+
+**Current value (from the default):** `[]`
+
+From //garnet/lib/magma/gnbuild/magma.gni:38
+
+### crash_diagnostics_dir
+Clang crash reports directory path. Use empty path to disable altogether.
+
+**Current value (from the default):** `"//root_build_dir/clang-crashreports"`
+
+From //build/config/BUILD.gn:9
+
+### dart_aot_sharing_basis
+module_suggester is not AOT compiled in debug builds
+
+**Current value (from the default):** `""`
+
+From [//topaz/runtime/dart/dart_component.gni:51](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#51)
+
+### create_kernel_service_snapshot
+
+**Current value (from the default):** `false`
+
+From //third_party/dart/runtime/runtime_args.gni:101
+
+### skia_use_lua
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:30
+
+### 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 for `target_cpu = "arm64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
+
+From //products/core.gni:26
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:30
+
+**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
+
+From //products/core.gni:26
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:30
+
+### crashpad_dependencies
+
+**Current value (from the default):** `"fuchsia"`
+
+From [//third_party/crashpad/build/crashpad_buildconfig.gni:22](https://chromium.googlesource.com/crashpad/crashpad/+/5081a90207ec5e39aefeeab4ccc3e4690ee5c1e5/build/crashpad_buildconfig.gni#22)
+
+### magma_enable_developer_build
+Enable this to have the msd include a suite of tests and invoke them
+automatically when the driver starts.
+
+**Current value (from the default):** `false`
+
+From //garnet/lib/magma/gnbuild/magma.gni:21
+
+### skia_use_fonthost_mac
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:24
+
+### scenic_ignore_vsync
+
+**Current value (from the default):** `false`
+
+From //garnet/lib/ui/gfx/BUILD.gn:8
+
+### vbmeta_r_partition
+
+**Current value (from the default):** `""`
+
+From //build/images/BUILD.gn:44
+
+### 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:9
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:34
+
+**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:drivers"]`
+
+From //boards/x64.gni:13
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:34
+
+### 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.
+
+**Current value (from the default):** `true`
+
+From //garnet/public/lib/escher/BUILD.gn:16
+
+### magma_python_path
+
+**Current value (from the default):** `"/b/s/w/ir/k/third_party/mako"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:14
+
+### skia_enable_nima
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:44
+
+### skia_tools_require_resources
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:59
+
+### skia_use_fixed_gamma_text
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:26
+
+### skia_use_piex
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:32
+
+### thinlto_jobs
+Number of parallel ThinLTO jobs.
+
+**Current value (from the default):** `8`
+
+From //build/config/lto/config.gni:13
+
+### enable_dart_analysis
+Enable all dart analysis
+
+**Current value (from the default):** `true`
+
+From //build/dart/dart_library.gni:15
+
+### 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):** `"8388608"`
+
+From //build/images/fvm.gni:19
+
+### skia_enable_fontmgr_win
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:71
+
+### use_ccache
+Set to true to enable compiling with ccache
+
+**Current value (from the default):** `false`
+
+From //build/toolchain/ccache.gni:9
+
+### 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
+
+### extra_manifest_args
+Extra args to globally apply to the manifest generation script.
+
+**Current value (from the default):** `[]`
+
+From //build/images/manifest.gni:22
+
+### skia_generate_workarounds
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:51
+
+### host_byteorder
+
+**Current value (from the default):** `"undefined"`
+
+From //build/config/host_byteorder.gni:7
+
+### skia_enable_vulkan_debug_layers
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:48
+
+### thinlto_cache_dir
+ThinLTO cache directory path.
+
+**Current value (from the default):** `"dartlang/thinlto-cache"`
+
+From //build/config/lto/config.gni:16
+
+### skia_enable_gpu
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/gn/skia.gni:11
+
+### zircon_build_root
+
+**Current value (from the default):** `"//zircon"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:12
+
+### export_x64_sdk_images
+
+**Current value (from the default):** `false`
+
+From //sdk/BUILD.gn:12
+
+### icu_use_data_file
+Tells icu to load an external data file rather than rely on the icudata
+being linked directly into the binary.
+
+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).
+
+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):** `true`
+
+From [//third_party/icu/config.gni:15](https://fuchsia.googlesource.com/third_party/icu/+/65e4aa3b8cc6b41cf31136b9474a9c97bdc27739/config.gni#15)
+
+### skia_compile_processors
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:50
+
+### skia_enable_flutter_defines
+
+**Current value for `target_cpu = "arm64"`:** `true`
+
+From //.gn:24
+
+**Overridden from the default:** `false`
+
+From //third_party/skia/BUILD.gn:16
+
+**Current value for `target_cpu = "x64"`:** `true`
+
+From //.gn:24
+
+**Overridden from the default:** `false`
+
+From //third_party/skia/BUILD.gn:16
+
+### skia_skqp_global_error_tolerance
+
+**Current value (from the default):** `0`
+
+From //third_party/skia/BUILD.gn:54
+
+### board_name
+Board name used for paving and amber updates.
+
+**Current value (from the default):** `""`
+
+From //build/package.gni:21
+
+### dart_snapshot_kind
+
+**Current value (from the default):** `"kernel"`
+
+From //third_party/dart/utils/application_snapshot.gni:14
+
+### dart_version
+
+**Current value (from the default):** `""`
+
+From //third_party/flutter/shell/version/version.gni:10
+
+### skia_use_fontconfig
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //.gn:28
+
+**Overridden from the default:** `false`
+
+From //third_party/skia/BUILD.gn:23
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //.gn:28
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:23
+
+### skia_use_x11
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //.gn:31
+
+**Overridden from the default:** `false`
+
+From //third_party/skia/BUILD.gn:37
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //.gn:31
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:37
+
+### cache_package_labels
+If you add package labels to this variable, the packages will be included
+in the 'cache' package set, which represents an additional set of software
+that is made available on disk immediately after paving and in factory
+flows. These packages are not updated with an OTA, but instead are updated
+ephemerally. This cache of software can be evicted by the system if storage
+pressure arises or other policies indicate.
+
+**Current value for `target_cpu = "arm64"`:** `[]`
+
+From //products/core.gni:24
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:22
+
+**Current value for `target_cpu = "x64"`:** `[]`
+
+From //products/core.gni:24
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:22
+
+### flutter_profile
+
+**Current value (from the default):** `true`
+
+From [//topaz/runtime/dart/dart_component.gni:32](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#32)
+
+### target_os
+
+**Current value (from the default):** `""`
+
+### 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"]`
+
+From //build/images/manifest.gni:11
+
+### build_info_board
+Board configuration of the current build
+
+**Current value (from the default):** `""`
+
+From //garnet/BUILD.gn:24
+
+### 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):** `false`
+
+From //third_party/dart/runtime/runtime_args.gni:43
+
+### skia_enable_ccpr
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:41
+
+### skia_qt_path
+
+**Current value (from the default):** `""`
+
+From //third_party/skia/BUILD.gn:49
+
+### expat_build_root
+
+**Current value (from the default):** `"//third_party/expat"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:9
+
+### msd_intel_gen_build_root
+
+**Current value (from the default):** `"//garnet/drivers/gpu/msd-intel-gen"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:10
+
+### use_lto
+Use link time optimization (LTO).
+
+**Current value (from the default):** `false`
+
+From //build/config/lto/config.gni:7
+
+### 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.
+
+**Current value (from the default):** `["abort_on_error=1", "QuarantineSizeKb=0", "ThreadLocalQuarantineSizeKb=0", "DeallocationTypeMismatch=false", "DeleteSizeMismatch=false", "allocator_may_return_null=true"]`
+
+From //build/config/scudo/scudo.gni:17
+
+### skia_use_metal
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:35
+
+### 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).
+
+**Current value (from the default):**
+```
+{
+  base = "//build/toolchain/fuchsia:arm64"
+}
+```
+
+From //build/config/BUILDCONFIG.gn:74
+
+### vk_loader_debug
+
+**Current value (from the default):** `"warn,error"`
+
+From [//third_party/vulkan_loader_and_validation_layers/loader/BUILD.gn:26](https://fuchsia.googlesource.com/third_party/vulkan_loader_and_validation_layers/+/62e58ed31dc9711381fbe80817a89b51e9ff0686/loader/BUILD.gn#26)
+
+### zircon_enable_kernel_debugging_features
+Whether to include various features (non-shipping, insecure, etc.) in the
+kernel build.
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //products/core.gni:9
+
+**Overridden from the default:** `false`
+
+From //build/config/fuchsia/zircon.gni:32
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //products/core.gni:9
+
+**Overridden from the default:** `false`
+
+From //build/config/fuchsia/zircon.gni:32
+
+### flutter_default_app
+
+**Current value (from the default):** `"flutter_jit_app"`
+
+From [//topaz/runtime/dart/dart_component.gni:12](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#12)
+
 ### minfs_maximum_bytes
 
 **Current value (from the default):** `""`
 
 From //build/images/fvm.gni:48
 
+### 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):** `"//build/development.key"`
+
+From //build/package.gni:18
+
+### vbmeta_a_partition
+
+**Current value (from the default):** `""`
+
+From //build/images/BUILD.gn:42
+
+### auto_update_packages
+Whether the component loader should automatically update packages.
+
+**Current value (from the default):** `true`
+
+From //garnet/bin/sysmgr/BUILD.gn:10
+
+### 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.
+
+**Current value (from the default):** `true`
+
+From [//third_party/crashpad/util/net/tls.gni:21](https://chromium.googlesource.com/crashpad/crashpad/+/5081a90207ec5e39aefeeab4ccc3e4690ee5c1e5/util/net/tls.gni#21)
+
+### dart_space_dart
+Whether experimental space dart mode is enabled for Dart applications.
+
+**Current value (from the default):** `false`
+
+From [//topaz/runtime/dart/dart_component.gni:41](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#41)
+
+### enable_input_subsystem
+
+**Current value (from the default):** `true`
+
+From //garnet/bin/ui/scenic/BUILD.gn:14
+
+### skia_enable_particles
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/modules/particles/BUILD.gn:7
+
+### 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):** `true`
+
+From //build/dart/dart.gni:15
+
+### is_debug
+Debug build.
+
+**Current value (from the default):** `true`
+
+From //build/config/BUILDCONFIG.gn:11
+
+### meta_package_labels
+A list of labels for meta packages to be included in the monolith.
+
+**Current value for `target_cpu = "arm64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//garnet/bin/component_index:component_index"]`
+
+From //products/core.gni:11
+
+**Overridden from the default:** `[]`
+
+From //build/images/BUILD.gn:36
+
+**Current value for `target_cpu = "x64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//garnet/bin/component_index:component_index"]`
+
+From //products/core.gni:11
+
+**Overridden from the default:** `[]`
+
+From //build/images/BUILD.gn:36
+
+### skia_enable_pdf
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //.gn:25
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:45
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //.gn:25
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:45
+
+### 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 (from the default):** `true`
+
+From //src/media/lib/ffmpeg/BUILD.gn:14
+
+### 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):**
+```
+{
+  default_deps = [":legacy-arm64"]
+  enable_kernel_debugging_features = false
+  goma_dir = "/home/swarming/goma"
+  use_goma = false
+  variants = []
+}
+```
+
+From //build/config/fuchsia/zircon.gni:45
+
+### always_zedboot
+Build boot images that prefer Zedboot over local boot (only for EFI).
+
+**Current value (from the default):** `false`
+
+From //build/images/BUILD.gn:796
+
+### 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.
+
+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'.
+
+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.
+
+**Current value (from the default):** `"develop"`
+
+From //third_party/dart/runtime/runtime_args.gni:28
+
+### have_secmem_ta
+The secmem TA must be obtained elsewhere and put into the firmware
+directory.
+
+**Current value (from the default):** `false`
+
+From //garnet/bin/sysmem-assistant/BUILD.gn:44
+
+### persist_logs
+
+**Current value (from the default):** `true`
+
+From //build/persist_logs.gni:13
+
+### 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):** `""`
+
+From //build/images/fvm.gni:12
+
+### log_startup_sleep
+
+**Current value (from the default):** `"30000"`
+
+From //garnet/bin/log_listener/BUILD.gn:14
+
+### 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.
+
+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):** `false`
+
+From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:23
+
+### flutter_space_dart
+Whether experimental space dart mode is enabled for Flutter applications.
+
+**Current value (from the default):** `false`
+
+From [//topaz/runtime/dart/dart_component.gni:38](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#38)
+
+### scenic_use_views2
+Temporary flag, switches Flutter to using Scenic's new View API.
+
+**Current value (from the default):** `false`
+
+From //garnet/bin/ui/scenic/config.gni:7
+
+### skia_enable_fontmgr_fuchsia
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:70
+
+### 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):** `""`
+
+From //build/images/fvm.gni:47
+
+### 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):** `"arm64"`
+
+From //third_party/dart/runtime/runtime_args.gni:32
+
+### 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
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //products/core.gni:7
+
+**Overridden from the default:** `false`
+
+From //build/images/BUILD.gn:33
+
+### scenic_use_new_renderer
+Specifies whether Scenic uses the new "PaperRenderer2" when
+rendering Scenes with fuchsia.ui.gfx.ShadowTechnique.UNSHADOWED.
+
+**Current value (from the default):** `true`
+
+From //garnet/lib/ui/gfx/BUILD.gn:12
+
+### magma_build_root
+
+**Current value (from the default):** `"//garnet/lib/magma"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:8
+
+### cloudkms_key_dir
+
+**Current value (from the default):** `"projects/fuchsia-infra/locations/global/keyRings/test-secrets/cryptoKeys"`
+
+From //build/testing/secret_spec.gni:8
+
+### current_cpu
+
+**Current value (from the default):** `""`
+
+### data_partition_manifest
+Path to manifest file containing data to place into the initial /data
+partition.
+
+**Current value (from the default):** `""`
+
+From //build/images/BUILD.gn:28
+
+### shell_enable_vulkan
+
+**Current value (from the default):** `false`
+
+From //third_party/flutter/shell/config.gni:6
+
+### skia_enable_fontmgr_win_gdi
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:72
+
+### update_kernels
+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 //build/images/BUILD.gn:488
+
+### use_goma
+Set to true to enable distributed compilation using Goma.
+
+**Current value (from the default):** `false`
+
+From //build/toolchain/goma.gni:9
+
+### zedboot_devmgr_config
+List of arguments to populate /boot/config/devmgr in the Zedboot image.
+
+**Current value (from the default):** `["netsvc.netboot=true"]`
+
+From //build/images/zedboot/BUILD.gn:26
+
+### 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):** `""`
+
+From //build/images/fvm.gni:36
+
+### exclude_kernel_service
+Whether the VM includes the kernel service in all modes (debug, release,
+product).
+
+**Current value (from the default):** `false`
+
+From //third_party/dart/runtime/runtime_args.gni:88
+
+### 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.
+
+**Current value (from the default):** `[]`
+
+From //build/images/BUILD.gn:476
+
+### linux_guest_extras_path
+
+**Current value (from the default):** `""`
+
+From //garnet/bin/guest/pkg/linux_guest/BUILD.gn:13
+
+### 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):** `[]`
+
+From //build/config/BUILDCONFIG.gn:627
+
+### skia_use_wuffs
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:33
+
+### skia_use_zlib
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:34
+
+### 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.
+
+**Current value (from the default):** `2`
+
+From //build/config/compiler.gni:13
+
+### build_info_product
+Product configuration of the current build
+
+**Current value (from the default):** `""`
+
+From //garnet/BUILD.gn:21
+
+### host_os
+
+**Current value (from the default):** `"linux"`
+
+### ledger_sync_credentials_file
+
+**Current value (from the default):** `""`
+
+From //src/ledger/bin/testing/sync_params.gni:6
+
+### zircon_b_partition
+
+**Current value (from the default):** `""`
+
+From //build/images/BUILD.gn:40
+
+### fuchsia_use_vulkan
+Consolidated build toggle for use of Vulkan across Fuchsia
+
+**Current value (from the default):** `true`
+
+From //build/vulkan/config.gni:7
+
+### signed_image
+
+**Current value (from the default):** `false`
+
+From //build/images/BUILD.gn:46
+
+### skia_use_libpng
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:28
+
+### concurrent_link_jobs
+Maximum number of concurrent link jobs.
+
+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.
+
+**Current value (from the default):** `16`
+
+From //build/toolchain/BUILD.gn:15
+
+### glm_build_root
+
+**Current value (from the default):** `"//third_party/glm"`
+
+From //garnet/lib/magma/gnbuild/magma.gni:11
+
+### skia_use_xps
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:38
+
+### skia_enable_fontmgr_empty
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:65
+
+### 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 //third_party/dart/runtime/runtime_args.gni:9
+
+### flutter_runtime_mode
+The runtime mode ("debug", "profile", "release", "dynamic_profile", or "dynamic_release")
+
+**Current value (from the default):** `"debug"`
+
+From //third_party/flutter/common/config.gni:15
+
+### 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.
+
+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.
+
+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 }`.
+
+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.
+
+The scope that forms a full selector defines some of these:
+
+    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).
+
+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.
+
+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.
+
+Each "[strings]" criterion is a list of strings, and the criterion
+is satisfied if any of the strings matches against the candidate string.
+
+    host
+        [boolean] If true, the selector matches in the host toolchain.
+        If false, the selector matches in the target toolchain.
+
+    testonly
+        [boolean] If true, the selector matches targets with testonly=true.
+        If false, the selector matches in targets without testonly=true.
+
+    target_type
+        [strings]: `"executable"`, `"loadable_module"`, or `"driver_module"`
+
+    output_name
+        [strings]: target's `output_name` (default: its `target name`)
+
+    label
+        [strings]: target's full label with `:` (without toolchain suffix)
+
+    name
+        [strings]: target's simple name (label after last `/` or `:`)
+
+    dir
+        [strings]: target's label directory (`//dir` for `//dir:name`).
+
+**Current value (from the default):** `[]`
+
+From //build/config/BUILDCONFIG.gn:622
+
+### use_thinlto
+Use ThinLTO variant of LTO if use_lto = true.
+
+**Current value (from the default):** `true`
+
+From //build/config/lto/config.gni:10
+
+### dart_force_product
+Forces all Dart and Flutter apps to build in a specific configuration that
+we use to build products.
+
+**Current value (from the default):** `false`
+
+From [//topaz/runtime/dart/config.gni:10](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/config.gni#10)
+
+### skia_enable_fontmgr_custom
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:67
+
 ### skia_pdf_subset_harfbuzz
 TODO: set skia_pdf_subset_harfbuzz to skia_use_harfbuzz.
 
@@ -26,18 +1495,461 @@
 
 From //third_party/skia/gn/skia.gni:18
 
-### skia_use_vulkan
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:87
-
-### debian_guest_qcow
-Package the rootfs as a QCOW image (as opposed to a flat file).
+### skia_enable_fontmgr_custom_empty
 
 **Current value (from the default):** `true`
 
-From //garnet/bin/guest/pkg/debian_guest/BUILD.gn:9
+From //third_party/skia/BUILD.gn:68
+
+### clang_lib_dir
+Path to Clang lib directory.
+
+**Current value (from the default):** `"../build/buildtools/linux-x64/clang/lib"`
+
+From //build/images/manifest.gni:19
+
+### skia_android_serial
+
+**Current value (from the default):** `""`
+
+From //third_party/skia/BUILD.gn:40
+
+### devmgr_config
+List of arguments to add to /boot/config/devmgr.
+These come after synthesized arguments to configure blobfs and pkgfs.
+
+**Current value (from the default):** `[]`
+
+From //build/images/BUILD.gn:465
+
+### skia_enable_skshaper
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/modules/skshaper/BUILD.gn:9
+
+### skia_gl_standard
+
+**Current value (from the default):** `""`
+
+From //third_party/skia/BUILD.gn:79
+
+### skia_use_libheif
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:36
+
+### skia_use_vulkan
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:85
+
+### skia_version
+
+**Current value (from the default):** `""`
+
+From //third_party/flutter/shell/version/version.gni:8
+
+### zircon_r_partition
+
+**Current value (from the default):** `""`
+
+From //build/images/BUILD.gn:41
+
+### framework_packages
+
+**Current value (from the default):** `["collection", "flutter", "meta", "typed_data", "vector_math"]`
+
+From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:8](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/flutter_runner/prebuilt_framework.gni#8)
+
+### sdk_dirs
+The directories to search for parts of the SDK.
+
+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):** `["//garnet/public", "//peridot/public", "//topaz/public"]`
+
+From //build/config/fuchsia/sdk.gni:10
+
+### select_variant_shortcuts
+List of short names for commonly-used variant selectors.  Normally this
+is not set as a build argument, but it serves to document the available
+set of short-cut names for variant selectors.  Each element of this list
+is a scope where `.name` is the short name and `.select_variant` is a
+a list that can be spliced into [`select_variant`](#select_variant).
+
+**Current value (from the default):**
+```
+[{
+  name = "host_asan"
+  select_variant = [{
+  dir = ["//third_party/yasm", "//third_party/vboot_reference", "//garnet/tools/vboot_reference"]
+  host = true
+  variant = "asan_no_detect_leaks"
+}, {
+  host = true
+  variant = "asan"
+}]
+}, {
+  name = "asan"
+  select_variant = [{
+  target_type = ["driver_module"]
+  variant = false
+}, {
+  host = false
+  variant = "asan"
+}]
+}]
+```
+
+From //build/config/BUILDCONFIG.gn:448
+
+### linux_runner_gateway
+
+**Current value (from the default):** `"10.0.0.1"`
+
+From //garnet/bin/guest/pkg/biscotti_guest/linux_runner/BUILD.gn:18
+
+### 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.
+
+**Current value (from the default):** `"0"`
+
+From //garnet/bin/log_listener/BUILD.gn:13
+
+### skia_enable_nvpr
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:42
+
+### skia_use_egl
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:21
+
+### skia_use_libwebp
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //.gn:29
+
+**Overridden from the default:** `false`
+
+From //third_party/skia/BUILD.gn:29
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //.gn:29
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:29
+
+### current_os
+
+**Current value (from the default):** `""`
+
+### 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.
+
+**Current value (from the default):** `"dart_jit_app"`
+
+From [//topaz/runtime/dart/dart_component.gni:19](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#19)
+
+### dart_use_crashpad
+Whether to link Crashpad library for crash handling. Only supported on
+Windows for now.
+
+**Current value (from the default):** `false`
+
+From //third_party/dart/runtime/runtime_args.gni:51
+
+### 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 (from the default):** `{ }`
+
+From //build/config/fuchsia/zircon.gni:27
+
+### 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 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 //root_build_dir/args.gn:3
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:14
+
+**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 //root_build_dir/args.gn:3
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:14
+
+### build_libvulkan_vsl_gc
+This is a list of targets that will be built as verisilicon vulkan ICDS.
+
+**Current value (from the default):** `[]`
+
+From //garnet/lib/magma/gnbuild/magma.gni:41
+
+### skia_use_opencl
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:31
+
+### use_vboot
+Use vboot images
+
+**Current value (from the default):** `false`
+
+From //build/images/boot.gni:11
+
+### 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).
+
+**Current value (from the default):** `[]`
+
+From //build/images/BUILD.gn:470
+
+### minfs_minimum_data_bytes
+
+**Current value (from the default):** `""`
+
+From //build/images/fvm.gni:37
+
+### skia_llvm_lib
+
+**Current value (from the default):** `"LLVM"`
+
+From //third_party/skia/BUILD.gn:57
+
+### enable_sketchy_subsystem
+
+**Current value (from the default):** `false`
+
+From //garnet/bin/ui/scenic/BUILD.gn:13
+
+### 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 (from the default):** `false`
+
+From //src/connectivity/wlan/lib/mlme/cpp/BUILD.gn:10
+
+### skia_enable_spirv_validation
+
+**Current value (from the default):** `false`
+
+From //third_party/skia/BUILD.gn:46
+
+### clang_prefix
+The default clang toolchain provided by the buildtools. This variable is
+additionally consumed by the Go toolchain.
+
+**Current value (from the default):** `"../buildtools/linux-x64/clang/bin"`
+
+From //build/config/clang/clang.gni:11
+
+### 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):** `true`
+
+From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:13
+
+### skia_enable_skottie
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/modules/skottie/BUILD.gn:9
+
+### skia_enable_skpicture
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:47
+
+### 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 //build/images/custom_signing.gni:16
+
+### vbmeta_b_partition
+
+**Current value (from the default):** `""`
+
+From //build/images/BUILD.gn:43
+
+### board_packages
+
+**Current value for `target_cpu = "arm64"`:** `[]`
+
+From //boards/arm64.gni:7
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:40
+
+**Current value for `target_cpu = "x64"`:** `[]`
+
+From //boards/x64.gni:9
+
+**Overridden from the default:** `[]`
+
+From //BUILD.gn:40
+
+### concurrent_rust_jobs
+Maximum number of Rust processes to run in parallel.
+
+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.
+
+**Current value (from the default):** `14`
+
+From //build/rust/BUILD.gn:15
+
+### magma_enable_tracing
+Enable this to include fuchsia tracing capability
+
+**Current value (from the default):** `true`
+
+From //garnet/lib/magma/gnbuild/magma.gni:17
+
+### zircon_asserts
+
+**Current value (from the default):** `true`
+
+From //build/config/fuchsia/BUILD.gn:201
+
+### full_dart_sdk
+
+**Current value (from the default):** `false`
+
+From //third_party/flutter/BUILD.gn:10
+
+### max_fvm_size
+Maximum allowable size for the FVM in a release mode build
+Zero means no limit
+
+**Current value (from the default):** `"0"`
+
+From //build/images/max_fvm_size.gni:8
+
+### skia_use_libjpeg_turbo
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:27
+
+### 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):** `"client"`
+
+From //src/connectivity/wlan/wlancfg/BUILD.gn:15
+
+### zircon_a_partition
+arguments to fx flash script
+
+**Current value (from the default):** `""`
+
+From //build/images/BUILD.gn:39
+
+### dart_component_kind
+Allow for deduping the VM between standalone, flutter_runner and dart_runner.
+
+**Current value (from the default):** `"shared_library"`
+
+From //third_party/dart/runtime/runtime_args.gni:78
+
+### 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
+
+### 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.
+
+**Current value (from the default):** `""`
+
+From [//topaz/runtime/dart/dart_component.gni:27](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#27)
+
+### 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):** `"core"`
+
+From //third_party/dart/runtime/runtime_args.gni:56
+
+### target_cpu
+
+**Current value for `target_cpu = "arm64"`:** `"arm64"`
+
+From //boards/arm64.gni:5
+
+**Overridden from the default:** `""`
+
+**Current value for `target_cpu = "x64"`:** `"x64"`
+
+From //boards/x64.gni:5
+
+**Overridden from the default:** `""`
+
+### 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):** `false`
+
+From //build/sdk/config.gni:8
 
 ### known_variants
 List of variants that will form the basis for variant toolchains.
@@ -153,230 +2065,46 @@
 
 From //build/config/BUILDCONFIG.gn:337
 
-### linux_runner_ip
-Default values for the guest network configuration.
+### rust_warnings
+Sets whether Rust compiler warnings cause errors or not.
+"deny" will make all warnings into errors, while "allow" will ignore warnings
 
-These are currently hard-coded to match what is setup in the virtio-net
-device.
+**Current value (from the default):** `"deny"`
 
-See //garnet/bin/guest/vmm/device/virtio_net.cc for more details.
+From //build/rust/config.gni:27
 
-**Current value (from the default):** `"10.0.0.2"`
-
-From //garnet/bin/guest/pkg/biscotti_guest/linux_runner/BUILD.gn:17
-
-### scenic_ignore_vsync
+### use_mock_magma
 
 **Current value (from the default):** `false`
 
-From //garnet/lib/ui/gfx/BUILD.gn:8
+From [//third_party/mesa/src/intel/vulkan/BUILD.gn:25](https://fuchsia.googlesource.com/third_party/mesa/+/1cfafcad803bc40d46133be708d5df1b4a604352/src/intel/vulkan/BUILD.gn#25)
 
-### allow_layer_guesswork
-Does nothing.
-
-Will be removed after 30 April 2019.
-
-**Current value (from the default):** `false`
-
-From //BUILD.gn:39
-
-### skia_enable_gpu
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/gn/skia.gni:11
-
-### zircon_r_partition
+### active_partition
 
 **Current value (from the default):** `""`
 
-From //build/images/BUILD.gn:41
+From //build/images/BUILD.gn:45
 
-### scenic_use_new_renderer
-Specifies whether Scenic uses the new "PaperRenderer2" when
-rendering Scenes with fuchsia.ui.gfx.ShadowTechnique.UNSHADOWED.
-
-**Current value (from the default):** `true`
-
-From //garnet/lib/ui/gfx/BUILD.gn:12
-
-### linux_runner_netmask
-
-**Current value (from the default):** `"255.255.255.0"`
-
-From //garnet/bin/guest/pkg/biscotti_guest/linux_runner/BUILD.gn:19
-
-### skia_qt_path
+### build_info_version
+Logical version of the current build. If not set, defaults to the timestamp
+of the most recent update.
 
 **Current value (from the default):** `""`
 
-From //third_party/skia/BUILD.gn:49
+From //garnet/BUILD.gn:28
 
-### skia_use_fontconfig
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //.gn:28
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:23
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //.gn:28
-
-**Overridden from the default:** `false`
-
-From //third_party/skia/BUILD.gn:23
-
-### use_ccache
-Set to true to enable compiling with ccache
-
-**Current value (from the default):** `false`
-
-From //build/toolchain/ccache.gni:9
-
-### zircon_build_root
-
-**Current value (from the default):** `"//zircon"`
-
-From //garnet/lib/magma/gnbuild/magma.gni:12
-
-### 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_qcom_adreno
+This is a list of targets that will be built as verisilicon vulkan ICDS.
 
 **Current value (from the default):** `[]`
 
-From //build/images/BUILD.gn:476
+From //garnet/lib/magma/gnbuild/magma.gni:44
 
-### skia_enable_spirv_validation
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:46
-
-### skia_skqp_global_error_tolerance
-
-**Current value (from the default):** `0`
-
-From //third_party/skia/BUILD.gn:54
-
-### skia_use_expat
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //.gn:27
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:22
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //.gn:27
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:22
-
-### skia_use_harfbuzz
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/gn/skia.gni:14
-
-### vbmeta_a_partition
+### prebuilt_framework_name
 
 **Current value (from the default):** `""`
 
-From //build/images/BUILD.gn:42
-
-### skia_compile_processors
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:50
-
-### max_fvm_size
-Maximum allowable size for the FVM in a release mode build
-Zero means no limit
-
-**Current value (from the default):** `"0"`
-
-From //build/images/max_fvm_size.gni:8
-
-### 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 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 //root_build_dir/args.gn:3
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:14
-
-**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 //root_build_dir/args.gn:3
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:14
-
-### skia_enable_nima
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:44
-
-### 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):** `""`
-
-From //build/images/fvm.gni:47
-
-### dart_use_tcmalloc
-Whether to link the standalone VM against tcmalloc. The standalone build of
-the VM enables this only for Linux builds.
-
-**Current value (from the default):** `false`
-
-From //third_party/dart/runtime/runtime_args.gni:47
-
-### 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):** `""`
-
-From //build/images/fvm.gni:12
-
-### 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/go/go_build.gni:20
+From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:7](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/flutter_runner/prebuilt_framework.gni#7)
 
 ### use_account_manager
 Whether basemgr and dev_base_shell should use account_manager for account
@@ -387,880 +2115,46 @@
 
 From //peridot/bin/basemgr/BUILD.gn:18
 
-### 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.
+### skia_enable_atlas_text
 
-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 //third_party/skia/BUILD.gn:64
 
-**Current value (from the default):** `"develop"`
-
-From //third_party/dart/runtime/runtime_args.gni:28
-
-### sdk_dirs
-The directories to search for parts of the SDK.
-
-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):** `["//garnet/public", "//peridot/public", "//topaz/public"]`
-
-From //build/config/fuchsia/sdk.gni:10
-
-### skia_enable_flutter_defines
-
-**Current value for `target_cpu = "arm64"`:** `true`
-
-From //.gn:24
-
-**Overridden from the default:** `false`
-
-From //third_party/skia/BUILD.gn:16
-
-**Current value for `target_cpu = "x64"`:** `true`
-
-From //.gn:24
-
-**Overridden from the default:** `false`
-
-From //third_party/skia/BUILD.gn:16
-
-### zircon_asserts
+### dart_version_git_info
+Whether the Dart binary version string should include the git hash and
+git commit time.
 
 **Current value (from the default):** `true`
 
-From //build/config/fuchsia/BUILD.gn:201
+From //third_party/dart/runtime/runtime_args.gni:60
 
-### flutter_profile
-
-**Current value (from the default):** `true`
-
-From [//topaz/runtime/dart/dart_component.gni:32](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#32)
-
-### skia_use_libpng
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:28
-
-### dart_space_dart
-Whether experimental space dart mode is enabled for Dart applications.
+### enable_mdns_trace
+Enables the tracing feature of mdns, which can be turned on using
+"mdns-util verbose".
 
 **Current value (from the default):** `false`
 
-From [//topaz/runtime/dart/dart_component.gni:41](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#41)
+From //garnet/bin/mdns/service/BUILD.gn:15
 
-### use_vboot
-Use vboot images
+### 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):** `false`
+**Current value (from the default):** `"/b/s/w/ir/k/root_build_dir/host_x64/.gocache"`
 
-From //build/images/boot.gni:11
+From //build/go/go_build.gni:16
 
-### host_cpu
+### 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):** `"x64"`
+**Current value (from the default):** `"//topaz/tools/prebuilt-dart-sdk/linux-x64"`
 
-### 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.
-
-**Current value (from the default):** `""`
-
-From [//topaz/runtime/dart/dart_component.gni:27](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#27)
-
-### concurrent_dart_jobs
-Maximum number of Dart processes to run in parallel.
-
-Dart analyzer uses a lot of memory which may cause issues when building
-with many parallel jobs e.g. when using goma. To avoid out-of-memory
-errors we explicitly reduce the number of jobs.
-
-**Current value (from the default):** `16`
-
-From //build/dart/BUILD.gn:15
-
-### 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.
-
-**Current value (from the default):** `"0"`
-
-From //garnet/bin/log_listener/BUILD.gn:13
-
-### 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 (from the default):** `true`
-
-From //src/media/lib/ffmpeg/BUILD.gn:14
-
-### clang_lib_dir
-Path to Clang lib directory.
-
-**Current value (from the default):** `"../build/buildtools/linux-x64/clang/lib"`
-
-From //build/images/manifest.gni:19
-
-### 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
-
-### minfs_minimum_inodes
-
-**Current value (from the default):** `""`
-
-From //build/images/fvm.gni:29
-
-### skia_enable_fontmgr_android
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:69
-
-### skia_enable_skpicture
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:47
-
-### skia_use_libjpeg_turbo
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:27
-
-### skia_use_metal
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:35
-
-### 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 //build/images/custom_signing.gni:16
-
-### clang_prefix
-The default clang toolchain provided by the buildtools. This variable is
-additionally consumed by the Go toolchain.
-
-**Current value (from the default):** `"../buildtools/linux-x64/clang/bin"`
-
-From //build/config/clang/clang.gni:11
-
-### 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.
-
-**Current value (from the default):** `2`
-
-From //build/config/compiler.gni:13
-
-### build_info_version
-Logical version of the current build. If not set, defaults to the timestamp
-of the most recent update.
-
-**Current value (from the default):** `""`
-
-From //garnet/BUILD.gn:28
-
-### dart_snapshot_kind
-
-**Current value (from the default):** `"kernel"`
-
-From //third_party/dart/utils/application_snapshot.gni:14
-
-### goma_dir
-Absolute directory containing the Goma source code.
-
-**Current value (from the default):** `"/home/swarming/goma"`
-
-From //build/toolchain/goma.gni:12
-
-### scenic_enable_vulkan_validation
-Include the vulkan validation layers in scenic.
-
-**Current value (from the default):** `true`
-
-From //garnet/bin/ui/BUILD.gn:40
-
-### board_name
-Board name used for paving and amber updates.
-
-**Current value (from the default):** `""`
-
-From //build/package.gni:21
-
-### expat_build_root
-
-**Current value (from the default):** `"//third_party/expat"`
-
-From //garnet/lib/magma/gnbuild/magma.gni:9
-
-### skia_enable_fontmgr_win_gdi
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:72
-
-### 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
-
-### msd_intel_gen_build_root
-
-**Current value (from the default):** `"//garnet/drivers/gpu/msd-intel-gen"`
-
-From //garnet/lib/magma/gnbuild/magma.gni:10
-
-### skia_enable_fontmgr_custom
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:67
-
-### target_sysroot
-The absolute path of the sysroot that is used with the target toolchain.
-
-**Current value (from the default):** `""`
-
-From //build/config/sysroot.gni:7
-
-### thinlto_jobs
-Number of parallel ThinLTO jobs.
-
-**Current value (from the default):** `8`
-
-From //build/config/lto/config.gni:13
-
-### 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"]`
-
-From //build/images/manifest.gni:11
-
-### dart_lib_export_symbols
-Whether libdart should export the symbols of the Dart API.
-
-**Current value (from the default):** `true`
-
-From //third_party/dart/runtime/runtime_args.gni:91
-
-### 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):** `false`
-
-From //third_party/dart/runtime/runtime_args.gni:43
-
-### 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/openssh-portable/fuchsia/developer-keys/BUILD.gn:11](https://fuchsia.googlesource.com/third_party/openssh-portable/+/f62e9e1879377736a8505bef9499df060613173d/fuchsia/developer-keys/BUILD.gn#11)
-
-### skia_use_lua
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:30
-
-### current_cpu
-
-**Current value (from the default):** `""`
-
-### 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 (from the default):** `{ }`
-
-From //build/config/fuchsia/zircon.gni:27
-
-### skia_enable_tools
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/gn/skia.gni:12
-
-### use_thinlto
-Use ThinLTO variant of LTO if use_lto = true.
-
-**Current value (from the default):** `true`
-
-From //build/config/lto/config.gni:10
-
-### skia_use_fonthost_mac
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:24
-
-### skia_use_xps
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:38
-
-### enable_input_subsystem
-
-**Current value (from the default):** `true`
-
-From //garnet/bin/ui/scenic/BUILD.gn:14
-
-### linux_guest_extras_path
-
-**Current value (from the default):** `""`
-
-From //garnet/bin/guest/pkg/linux_guest/BUILD.gn:13
-
-### 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):** `"deny"`
-
-From //build/rust/config.gni:27
-
-### always_zedboot
-Build boot images that prefer Zedboot over local boot (only for EFI).
-
-**Current value (from the default):** `false`
-
-From //build/images/BUILD.gn:796
-
-### skia_android_serial
-
-**Current value (from the default):** `""`
-
-From //third_party/skia/BUILD.gn:40
-
-### skia_llvm_path
-
-**Current value (from the default):** `""`
-
-From //third_party/skia/BUILD.gn:56
-
-### use_goma
-Set to true to enable distributed compilation using Goma.
-
-**Current value (from the default):** `false`
-
-From //build/toolchain/goma.gni:9
-
-### flutter_runtime_mode
-The runtime mode ("debug", "profile", "release", "dynamic_profile", or "dynamic_release")
-
-**Current value (from the default):** `"debug"`
-
-From //third_party/flutter/common/config.gni:15
-
-### 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.
-
-**Current value (from the default):** `true`
-
-From [//third_party/crashpad/util/net/tls.gni:21](https://chromium.googlesource.com/crashpad/crashpad/+/5081a90207ec5e39aefeeab4ccc3e4690ee5c1e5/util/net/tls.gni#21)
-
-### create_kernel_service_snapshot
-
-**Current value (from the default):** `false`
-
-From //third_party/dart/runtime/runtime_args.gni:101
-
-### magma_enable_developer_build
-Enable this to have the msd include a suite of tests and invoke them
-automatically when the driver starts.
-
-**Current value (from the default):** `false`
-
-From //garnet/lib/magma/gnbuild/magma.gni:21
-
-### skia_enable_fontmgr_win
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:71
-
-### skia_tools_require_resources
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:59
-
-### board_packages
-
-**Current value for `target_cpu = "arm64"`:** `[]`
-
-From //boards/arm64.gni:7
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:40
-
-**Current value for `target_cpu = "x64"`:** `[]`
-
-From //boards/x64.gni:9
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:40
-
-### enable_dart_analysis
-Enable all dart analysis
-
-**Current value (from the default):** `true`
-
-From //build/dart/dart_library.gni:15
-
-### cache_package_labels
-If you add package labels to this variable, the packages will be included
-in the 'cache' package set, which represents an additional set of software
-that is made available on disk immediately after paving and in factory
-flows. These packages are not updated with an OTA, but instead are updated
-ephemerally. This cache of software can be evicted by the system if storage
-pressure arises or other policies indicate.
-
-**Current value for `target_cpu = "arm64"`:** `[]`
-
-From //products/core.gni:24
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:22
-
-**Current value for `target_cpu = "x64"`:** `[]`
-
-From //products/core.gni:24
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:22
-
-### magma_enable_tracing
-Enable this to include fuchsia tracing capability
-
-**Current value (from the default):** `true`
-
-From //garnet/lib/magma/gnbuild/magma.gni:17
-
-### magma_python_path
-
-**Current value (from the default):** `"/b/s/w/ir/k/third_party/mako"`
-
-From //garnet/lib/magma/gnbuild/magma.gni:14
-
-### 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):** `true`
-
-From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:13
-
-### persist_logs
-
-**Current value (from the default):** `true`
-
-From //build/persist_logs.gni:13
-
-### select_variant_shortcuts
-List of short names for commonly-used variant selectors.  Normally this
-is not set as a build argument, but it serves to document the available
-set of short-cut names for variant selectors.  Each element of this list
-is a scope where `.name` is the short name and `.select_variant` is a
-a list that can be spliced into [`select_variant`](#select_variant).
-
-**Current value (from the default):**
-```
-[{
-  name = "host_asan"
-  select_variant = [{
-  dir = ["//third_party/yasm", "//third_party/vboot_reference", "//garnet/tools/vboot_reference"]
-  host = true
-  variant = "asan_no_detect_leaks"
-}, {
-  host = true
-  variant = "asan"
-}]
-}, {
-  name = "asan"
-  select_variant = [{
-  target_type = ["driver_module"]
-  variant = false
-}, {
-  host = false
-  variant = "asan"
-}]
-}]
-```
-
-From //build/config/BUILDCONFIG.gn:448
-
-### skia_enable_skottie
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/modules/skottie/BUILD.gn:9
-
-### skia_use_piex
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:32
-
-### extra_variants
-Additional variant toolchain configs to support.
-This is just added to [`known_variants`](#known_variants).
-
-**Current value (from the default):** `[]`
-
-From //build/config/BUILDCONFIG.gn:402
-
-### 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.
-
-**Current value (from the default):** `["abort_on_error=1", "QuarantineSizeKb=0", "ThreadLocalQuarantineSizeKb=0", "DeallocationTypeMismatch=false", "DeleteSizeMismatch=false", "allocator_may_return_null=true"]`
-
-From //build/config/scudo/scudo.gni:17
-
-### skia_gl_standard
-
-**Current value (from the default):** `""`
-
-From //third_party/skia/BUILD.gn:79
-
-### zircon_b_partition
-
-**Current value (from the default):** `""`
-
-From //build/images/BUILD.gn:40
-
-### have_secmem_ta
-The secmem TA must be obtained elsewhere and put into the firmware
-directory.
-
-**Current value (from the default):** `false`
-
-From //garnet/bin/sysmem-assistant/BUILD.gn:44
-
-### rustc_prefix
-Sets a custom base directory for `rustc` and `cargo`.
-This can be used to test custom Rust toolchains.
-
-**Current value (from the default):** `"//buildtools/linux-x64/rust/bin"`
-
-From //build/rust/config.gni:17
-
-### skia_generate_workarounds
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:51
-
-### skia_use_libwebp
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //.gn:29
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:29
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //.gn:29
-
-**Overridden from the default:** `false`
-
-From //third_party/skia/BUILD.gn:29
-
-### 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):** `false`
-
-From //build/sdk/config.gni:8
-
-### framework_packages
-
-**Current value (from the default):** `["collection", "flutter", "meta", "typed_data", "vector_math"]`
-
-From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:8](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/flutter_runner/prebuilt_framework.gni#8)
-
-### devmgr_config
-List of arguments to add to /boot/config/devmgr.
-These come after synthesized arguments to configure blobfs and pkgfs.
-
-**Current value (from the default):** `[]`
-
-From //build/images/BUILD.gn:465
-
-### host_byteorder
-
-**Current value (from the default):** `"undefined"`
-
-From //build/config/host_byteorder.gni:7
-
-### signed_image
-
-**Current value (from the default):** `false`
-
-From //build/images/BUILD.gn:46
-
-### debian_guest_earlycon
-
-**Current value (from the default):** `false`
-
-From //garnet/bin/guest/pkg/debian_guest/BUILD.gn:10
-
-### 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
-
-### 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.
-
-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):** `false`
-
-From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:23
-
-### skia_use_x11
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //.gn:31
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:37
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //.gn:31
-
-**Overridden from the default:** `false`
-
-From //third_party/skia/BUILD.gn:37
-
-### thinlto_cache_dir
-ThinLTO cache directory path.
-
-**Current value (from the default):** `"dartlang/thinlto-cache"`
-
-From //build/config/lto/config.gni:16
-
-### exclude_kernel_service
-Whether the VM includes the kernel service in all modes (debug, release,
-product).
-
-**Current value (from the default):** `false`
-
-From //third_party/dart/runtime/runtime_args.gni:88
-
-### skia_use_dng_sdk
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //.gn:26
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:62
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //.gn:26
-
-**Overridden from the default:** `false`
-
-From //third_party/skia/BUILD.gn:62
-
-### flutter_default_app
-
-**Current value (from the default):** `"flutter_jit_app"`
-
-From [//topaz/runtime/dart/dart_component.gni:12](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#12)
-
-### 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.
-
-**Current value (from the default):** `true`
-
-From //garnet/lib/magma/gnbuild/magma.gni:31
-
-### vk_loader_debug
-
-**Current value (from the default):** `"warn,error"`
-
-From [//third_party/vulkan_loader_and_validation_layers/loader/BUILD.gn:26](https://fuchsia.googlesource.com/third_party/vulkan_loader_and_validation_layers/+/62e58ed31dc9711381fbe80817a89b51e9ff0686/loader/BUILD.gn#26)
-
-### skia_use_freetype
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:25
-
-### prebuilt_libvulkan_arm_path
-
-**Current value (from the default):** `""`
-
-From //garnet/lib/magma/gnbuild/magma.gni:23
-
-### skia_version
-
-**Current value (from the default):** `""`
-
-From //third_party/flutter/shell/version/version.gni:8
-
-### zircon_enable_kernel_debugging_features
-Whether to include various features (non-shipping, insecure, etc.) in the
-kernel build.
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //products/core.gni:9
-
-**Overridden from the default:** `false`
-
-From //build/config/fuchsia/zircon.gni:32
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //products/core.gni:9
-
-**Overridden from the default:** `false`
-
-From //build/config/fuchsia/zircon.gni:32
-
-### msd_arm_enable_all_cores
-Enable all 8 cores, which is faster but emits more heat.
-
-**Current value (from the default):** `true`
-
-From //garnet/drivers/gpu/msd-arm-mali/src/BUILD.gn:9
-
-### skia_enable_nvpr
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:42
-
-### skia_enable_particles
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/modules/particles/BUILD.gn:7
-
-### target_cpu
-
-**Current value for `target_cpu = "arm64"`:** `"arm64"`
-
-From //boards/arm64.gni:5
-
-**Overridden from the default:** `""`
-
-**Current value for `target_cpu = "x64"`:** `"x64"`
-
-From //boards/x64.gni:5
-
-**Overridden from the default:** `""`
-
-### universal_variants
-
-**Current value (from the default):**
-```
-[{
-  configs = []
-  name = "release"
-  toolchain_args = {
-  is_debug = false
-}
-}]
-```
-
-From //build/config/BUILDCONFIG.gn:422
-
-### use_mock_magma
-
-**Current value (from the default):** `false`
-
-From [//third_party/mesa/src/intel/vulkan/BUILD.gn:25](https://fuchsia.googlesource.com/third_party/mesa/+/1cfafcad803bc40d46133be708d5df1b4a604352/src/intel/vulkan/BUILD.gn#25)
+From //build/dart/dart.gni:9
 
 ### use_scudo
 TODO(davemoore): Remove this entire mechanism once standalone scudo is the
@@ -1272,227 +2166,14 @@
 
 From //build/config/scudo/scudo.gni:10
 
-### glm_build_root
+### allow_layer_guesswork
+Does nothing.
 
-**Current value (from the default):** `"//third_party/glm"`
-
-From //garnet/lib/magma/gnbuild/magma.gni:11
-
-### skia_enable_skshaper
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/modules/skshaper/BUILD.gn:9
-
-### dart_component_kind
-Allow for deduping the VM between standalone, flutter_runner and dart_runner.
-
-**Current value (from the default):** `"shared_library"`
-
-From //third_party/dart/runtime/runtime_args.gni:78
-
-### icu_use_data_file
-Tells icu to load an external data file rather than rely on the icudata
-being linked directly into the binary.
-
-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).
-
-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):** `true`
-
-From [//third_party/icu/config.gni:15](https://fuchsia.googlesource.com/third_party/icu/+/65e4aa3b8cc6b41cf31136b9474a9c97bdc27739/config.gni#15)
-
-### rust_lto
-Sets the default LTO type for rustc bulids.
-
-**Current value (from the default):** `"unset"`
-
-From //build/rust/config.gni:20
-
-### skia_use_wuffs
+Will be removed after 30 April 2019.
 
 **Current value (from the default):** `false`
 
-From //third_party/skia/BUILD.gn:33
-
-### host_os
-
-**Current value (from the default):** `"linux"`
-
-### 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
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //products/core.gni:7
-
-**Overridden from the default:** `false`
-
-From //build/images/BUILD.gn:33
-
-### magma_build_root
-
-**Current value (from the default):** `"//garnet/lib/magma"`
-
-From //garnet/lib/magma/gnbuild/magma.gni:8
-
-### meta_package_labels
-A list of labels for meta packages to be included in the monolith.
-
-**Current value for `target_cpu = "arm64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//garnet/bin/component_index:component_index"]`
-
-From //products/core.gni:11
-
-**Overridden from the default:** `[]`
-
-From //build/images/BUILD.gn:36
-
-**Current value for `target_cpu = "x64"`:** `["//build/images:config-data", "//build/images:shell-commands", "//garnet/bin/component_index:component_index"]`
-
-From //products/core.gni:11
-
-**Overridden from the default:** `[]`
-
-From //build/images/BUILD.gn:36
-
-### use_lto
-Use link time optimization (LTO).
-
-**Current value (from the default):** `false`
-
-From //build/config/lto/config.gni:7
-
-### cloudkms_key_dir
-
-**Current value (from the default):** `"projects/fuchsia-infra/locations/global/keyRings/test-secrets/cryptoKeys"`
-
-From //build/testing/secret_spec.gni:8
-
-### 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
-
-### 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/flutter/shell/platform/embedder/embedder.gni:12
-
-### enable_mdns_trace
-Enables the tracing feature of mdns, which can be turned on using
-"mdns-util verbose".
-
-**Current value (from the default):** `false`
-
-From //garnet/bin/mdns/service/BUILD.gn:15
-
-### 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):** `"8388608"`
-
-From //build/images/fvm.gni:19
-
-### dart_aot_sharing_basis
-module_suggester is not AOT compiled in debug builds
-
-**Current value (from the default):** `""`
-
-From [//topaz/runtime/dart/dart_component.gni:51](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#51)
-
-### zircon_a_partition
-arguments to fx flash script
-
-**Current value (from the default):** `""`
-
-From //build/images/BUILD.gn:39
-
-### active_partition
-
-**Current value (from the default):** `""`
-
-From //build/images/BUILD.gn:45
-
-### crashpad_dependencies
-
-**Current value (from the default):** `"fuchsia"`
-
-From [//third_party/crashpad/build/crashpad_buildconfig.gni:22](https://chromium.googlesource.com/crashpad/crashpad/+/5081a90207ec5e39aefeeab4ccc3e4690ee5c1e5/build/crashpad_buildconfig.gni#22)
-
-### dart_use_crashpad
-Whether to link Crashpad library for crash handling. Only supported on
-Windows for now.
-
-**Current value (from the default):** `false`
-
-From //third_party/dart/runtime/runtime_args.gni:51
-
-### enable_value_subsystem
-
-**Current value (from the default):** `false`
-
-From //garnet/bin/ui/scenic/BUILD.gn:11
-
-### 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).
-
-**Current value (from the default):** `[]`
-
-From //build/images/BUILD.gn:470
-
-### build_sdk_archives
-Whether to build SDK tarballs.
-
-**Current value (from the default):** `false`
-
-From //build/sdk/sdk.gni:13
-
-### 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):** `"arm64"`
-
-From //third_party/dart/runtime/runtime_args.gni:32
+From //BUILD.gn:39
 
 ### enable_frame_pointers
 Controls whether the compiler emits full stack frames for function calls.
@@ -1507,316 +2188,12 @@
 
 From //build/config/BUILD.gn:19
 
-### enable_gfx_subsystem
+### fuchsia_vulkan_sdk
+Path to Fuchsia Vulkan SDK
 
-**Current value (from the default):** `true`
+**Current value (from the default):** `"//third_party/vulkan_loader_and_validation_layers"`
 
-From //garnet/bin/ui/scenic/BUILD.gn:12
-
-### log_startup_sleep
-
-**Current value (from the default):** `"30000"`
-
-From //garnet/bin/log_listener/BUILD.gn:14
-
-### shell_enable_vulkan
-
-**Current value (from the default):** `false`
-
-From //third_party/flutter/shell/config.gni:6
-
-### skia_enable_pdf
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //.gn:25
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:45
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //.gn:25
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:45
-
-### skia_use_opencl
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:31
-
-### 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:9
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:34
-
-**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:drivers"]`
-
-From //boards/x64.gni:13
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:34
-
-### current_os
-
-**Current value (from the default):** `""`
-
-### 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):** `"core"`
-
-From //third_party/dart/runtime/runtime_args.gni:56
-
-### sdk_id
-Identifier for the Core SDK.
-
-**Current value (from the default):** `""`
-
-From //sdk/config.gni:7
-
-### 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).
-
-**Current value (from the default):** `[]`
-
-From //build/images/zedboot/BUILD.gn:17
-
-### concurrent_link_jobs
-Maximum number of concurrent link jobs.
-
-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.
-
-**Current value (from the default):** `16`
-
-From //build/toolchain/BUILD.gn:15
-
-### linux_runner_gateway
-
-**Current value (from the default):** `"10.0.0.1"`
-
-From //garnet/bin/guest/pkg/biscotti_guest/linux_runner/BUILD.gn:18
-
-### skia_enable_discrete_gpu
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:43
-
-### target_os
-
-**Current value (from the default):** `""`
-
-### 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 (from the default):** `false`
-
-From //src/connectivity/wlan/lib/mlme/cpp/BUILD.gn:10
-
-### dart_force_product
-Forces all Dart and Flutter apps to build in a specific configuration that
-we use to build products.
-
-**Current value (from the default):** `false`
-
-From [//topaz/runtime/dart/config.gni:10](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/config.gni#10)
-
-### skia_enable_atlas_text
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:64
-
-### skia_enable_fontmgr_empty
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:65
-
-### build_info_board
-Board configuration of the current build
-
-**Current value (from the default):** `""`
-
-From //garnet/BUILD.gn:24
-
-### fuchsia_use_vulkan
-Consolidated build toggle for use of Vulkan across Fuchsia
-
-**Current value (from the default):** `true`
-
-From //build/vulkan/config.gni:7
-
-### 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):** `"//topaz/tools/prebuilt-dart-sdk/linux-x64"`
-
-From //build/dart/dart.gni:9
-
-### concurrent_rust_jobs
-Maximum number of Rust processes to run in parallel.
-
-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.
-
-**Current value (from the default):** `14`
-
-From //build/rust/BUILD.gn:15
-
-### dart_version
-
-**Current value (from the default):** `""`
-
-From //third_party/flutter/shell/version/version.gni:10
-
-### scenic_use_views2
-Temporary flag, switches Flutter to using Scenic's new View API.
-
-**Current value (from the default):** `false`
-
-From //garnet/bin/ui/scenic/config.gni:7
-
-### 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):** `true`
-
-From //build/dart/dart.gni:15
-
-### crash_diagnostics_dir
-Clang crash reports directory path. Use empty path to disable altogether.
-
-**Current value (from the default):** `"//root_build_dir/clang-crashreports"`
-
-From //build/config/BUILD.gn:9
-
-### skia_llvm_lib
-
-**Current value (from the default):** `"LLVM"`
-
-From //third_party/skia/BUILD.gn:57
-
-### skia_use_angle
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:20
-
-### skia_enable_fontmgr_fuchsia
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:70
-
-### enable_sketchy_subsystem
-
-**Current value (from the default):** `false`
-
-From //garnet/bin/ui/scenic/BUILD.gn:13
-
-### 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.
-
-**Current value (from the default):** `true`
-
-From //garnet/public/lib/escher/BUILD.gn:16
-
-### ledger_sync_credentials_file
-
-**Current value (from the default):** `""`
-
-From //src/ledger/bin/testing/sync_params.gni:6
-
-### skia_use_icu
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/gn/skia.gni:13
-
-### 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 //third_party/dart/runtime/runtime_args.gni:9
-
-### extra_manifest_args
-Extra args to globally apply to the manifest generation script.
-
-**Current value (from the default):** `[]`
-
-From //build/images/manifest.gni:22
-
-### skia_enable_vulkan_debug_layers
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:48
-
-### skia_use_egl
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:21
-
-### vbmeta_b_partition
-
-**Current value (from the default):** `""`
-
-From //build/images/BUILD.gn:43
-
-### vbmeta_r_partition
-
-**Current value (from the default):** `""`
-
-From //build/images/BUILD.gn:44
-
-### 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):** `[]`
-
-From //build/images/zedboot/BUILD.gn:23
+From //build/vulkan/config.gni:10
 
 ### concurrent_go_jobs
 Maximum number of Go processes to run in parallel.
@@ -1825,425 +2202,6 @@
 
 From //build/go/BUILD.gn:11
 
-### 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.
-
-**Current value (from the default):** `"dart_jit_app"`
-
-From [//topaz/runtime/dart/dart_component.gni:19](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#19)
-
-### dart_version_git_info
-Whether the Dart binary version string should include the git hash and
-git commit time.
-
-**Current value (from the default):** `true`
-
-From //third_party/dart/runtime/runtime_args.gni:60
-
-### data_partition_manifest
-Path to manifest file containing data to place into the initial /data
-partition.
-
-**Current value (from the default):** `""`
-
-From //build/images/BUILD.gn:28
-
-### export_x64_sdk_images
-
-**Current value (from the default):** `false`
-
-From //sdk/BUILD.gn:12
-
-### prebuilt_framework_path
-
-**Current value (from the default):** `""`
-
-From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:6](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/flutter_runner/prebuilt_framework.gni#6)
-
-### rust_toolchain_triple_suffix
-Sets the fuchsia toolchain target triple suffix (after arch)
-
-**Current value (from the default):** `"fuchsia"`
-
-From //build/rust/config.gni:23
-
-### skia_use_libheif
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:36
-
-### build_info_product
-Product configuration of the current build
-
-**Current value (from the default):** `""`
-
-From //garnet/BUILD.gn:21
-
-### minfs_minimum_data_bytes
-
-**Current value (from the default):** `""`
-
-From //build/images/fvm.gni:37
-
-### 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):** `""`
-
-From //build/images/fvm.gni:36
-
-### engine_version
-
-**Current value (from the default):** `""`
-
-From //third_party/flutter/shell/version/version.gni:6
-
-### 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).
-
-**Current value (from the default):** `"//root_build_dir/tools"`
-
-From //build/host.gni:13
-
-### 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):** `"client"`
-
-From //src/connectivity/wlan/wlancfg/BUILD.gn:15
-
-### build_libvulkan_vsl_gc
-This is a list of targets that will be built as verisilicon vulkan ICDS.
-
-**Current value (from the default):** `[]`
-
-From //garnet/lib/magma/gnbuild/magma.gni:41
-
-### full_dart_sdk
-
-**Current value (from the default):** `false`
-
-From //third_party/flutter/BUILD.gn:10
-
-### 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.
-
-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.
-
-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 }`.
-
-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.
-
-The scope that forms a full selector defines some of these:
-
-    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).
-
-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.
-
-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.
-
-Each "[strings]" criterion is a list of strings, and the criterion
-is satisfied if any of the strings matches against the candidate string.
-
-    host
-        [boolean] If true, the selector matches in the host toolchain.
-        If false, the selector matches in the target toolchain.
-
-    testonly
-        [boolean] If true, the selector matches targets with testonly=true.
-        If false, the selector matches in targets without testonly=true.
-
-    target_type
-        [strings]: `"executable"`, `"loadable_module"`, or `"driver_module"`
-
-    output_name
-        [strings]: target's `output_name` (default: its `target name`)
-
-    label
-        [strings]: target's full label with `:` (without toolchain suffix)
-
-    name
-        [strings]: target's simple name (label after last `/` or `:`)
-
-    dir
-        [strings]: target's label directory (`//dir` for `//dir:name`).
-
-**Current value (from the default):** `[]`
-
-From //build/config/BUILDCONFIG.gn:622
-
-### dart_platform_bytecode
-Whether the VM's platform dill file contains bytecode.
-
-**Current value (from the default):** `false`
-
-From //third_party/dart/runtime/runtime_args.gni:84
-
-### build_libvulkan_arm_mali
-This is a list of targets that will be built as mali vulkan ICDS.
-
-**Current value (from the default):** `[]`
-
-From //garnet/lib/magma/gnbuild/magma.gni:38
-
-### 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"`
-
-From //build/go/go_build.gni:16
-
-### 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):** `[]`
-
-From //build/config/BUILDCONFIG.gn:627
-
-### zedboot_devmgr_config
-List of arguments to populate /boot/config/devmgr in the Zedboot image.
-
-**Current value (from the default):** `["netsvc.netboot=true"]`
-
-From //build/images/zedboot/BUILD.gn:26
-
-### zxcrypt_key_source
-This argument specifies from where the system should obtain the zxcrypt
-master key to the system data partition.
-
-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.
-
-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.
-
-In the future, we may consider adding support for TPMs, or additional logic
-to explicitly support fallback behavior.
-
-**Current value (from the default):** `"null"`
-
-From //build/images/zxcrypt.gni:23
-
-### 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 (from the default):** `[]`
-
-From //build/images/BUILD.gn:482
-
-### skia_use_fixed_gamma_text
-
-**Current value (from the default):** `false`
-
-From //third_party/skia/BUILD.gn:26
-
-### update_kernels
-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 //build/images/BUILD.gn:488
-
-### is_debug
-Debug build.
-
-**Current value (from the default):** `true`
-
-From //build/config/BUILDCONFIG.gn:11
-
-### build_libvulkan_qcom_adreno
-This is a list of targets that will be built as verisilicon vulkan ICDS.
-
-**Current value (from the default):** `[]`
-
-From //garnet/lib/magma/gnbuild/magma.gni:44
-
-### 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):** `"//build/development.key"`
-
-From //build/package.gni:18
-
-### 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).
-
-**Current value (from the default):**
-```
-{
-  base = "//build/toolchain/fuchsia:arm64"
-}
-```
-
-From //build/config/BUILDCONFIG.gn:74
-
-### 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 for `target_cpu = "arm64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
-
-From //products/core.gni:26
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:30
-
-**Current value for `target_cpu = "x64"`:** `["//garnet/packages/prod:vboot_reference", "//bundles:tools"]`
-
-From //products/core.gni:26
-
-**Overridden from the default:** `[]`
-
-From //BUILD.gn:30
-
-### auto_login_to_guest
-Whether basemgr should automatically login as a persistent guest user.
-
-**Current value (from the default):** `false`
-
-From //peridot/bin/basemgr/BUILD.gn:13
-
-### 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):** `"2"`
-
-From //third_party/dart/runtime/runtime_args.gni:36
-
-### flutter_space_dart
-Whether experimental space dart mode is enabled for Flutter applications.
-
-**Current value (from the default):** `false`
-
-From [//topaz/runtime/dart/dart_component.gni:38](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/dart/dart_component.gni#38)
-
-### skia_enable_ccpr
-
-**Current value (from the default):** `true`
-
-From //third_party/skia/BUILD.gn:41
-
-### auto_update_packages
-Whether the component loader should automatically update packages.
-
-**Current value (from the default):** `true`
-
-From //garnet/bin/sysmgr/BUILD.gn:10
-
-### prebuilt_framework_name
-
-**Current value (from the default):** `""`
-
-From [//topaz/runtime/flutter_runner/prebuilt_framework.gni:7](https://fuchsia.googlesource.com/topaz/+/ff9f85507acd416f76801f1a561574b28c48446d/runtime/flutter_runner/prebuilt_framework.gni#7)
-
-### skia_use_sfntly
-
-**Current value for `target_cpu = "arm64"`:** `false`
-
-From //.gn:30
-
-**Overridden from the default:** `true`
-
-From //third_party/skia/BUILD.gn:63
-
-**Current value for `target_cpu = "x64"`:** `false`
-
-From //.gn:30
-
-**Overridden from the default:** `false`
-
-From //third_party/skia/BUILD.gn:63
-
 ### 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
@@ -2254,50 +2212,98 @@
 
 From //build/images/custom_signing.gni:12
 
-### skia_lex
+### 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).
 
-**Current value (from the default):** `false`
+**Current value (from the default):** `[]`
 
-From //third_party/skia/BUILD.gn:52
+From //build/images/zedboot/BUILD.gn:17
 
-### skia_use_zlib
+### 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):** `[]`
+
+From //build/images/zedboot/BUILD.gn:23
+
+### 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 (from the default):** `[]`
+
+From //build/images/BUILD.gn:482
+
+### skia_use_sfntly
+
+**Current value for `target_cpu = "arm64"`:** `false`
+
+From //.gn:30
+
+**Overridden from the default:** `false`
+
+From //third_party/skia/BUILD.gn:63
+
+**Current value for `target_cpu = "x64"`:** `false`
+
+From //.gn:30
+
+**Overridden from the default:** `true`
+
+From //third_party/skia/BUILD.gn:63
+
+### 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.
 
 **Current value (from the default):** `true`
 
-From //third_party/skia/BUILD.gn:34
+From //garnet/lib/magma/gnbuild/magma.gni:31
 
-### 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.
+### prebuilt_libvulkan_arm_path
 
-**Current value (from the default):**
-```
-{
-  default_deps = [":legacy-arm64"]
-  enable_kernel_debugging_features = false
-  goma_dir = "/home/swarming/goma"
-  use_goma = false
-  variants = []
-}
-```
+**Current value (from the default):** `""`
 
-From //build/config/fuchsia/zircon.gni:45
+From //garnet/lib/magma/gnbuild/magma.gni:23
 
-### skia_enable_fontmgr_custom_empty
+### rustc_prefix
+Sets a custom base directory for `rustc` and `cargo`.
+This can be used to test custom Rust toolchains.
+
+**Current value (from the default):** `"//buildtools/linux-x64/rust/bin"`
+
+From //build/rust/config.gni:17
+
+### dart_platform_bytecode
+Whether the VM's platform dill file contains bytecode.
 
 **Current value (from the default):** `false`
 
-From //third_party/skia/BUILD.gn:68
+From //third_party/dart/runtime/runtime_args.gni:84
+
+### skia_enable_discrete_gpu
+
+**Current value (from the default):** `true`
+
+From //third_party/skia/BUILD.gn:43
 
 ## `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
@@ -2336,12 +2342,6 @@
 
 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 c3621cc..303a80b 100644
--- a/zircon/docs/gen/build_arguments.md
+++ b/zircon/docs/gen/build_arguments.md

@@ -2,84 +2,6 @@
 
 ## All builds
 
-### 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):** `"/b/s/w/ir/k/out/build-zircon/.build-id"`
-
-From //public/gn/toolchain/c_toolchain.gni:17
-
-### 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:10
-
-### enable_fair_scheduler
-Enable fair scheduler by default on all architectures.
-
-**Current value (from the default):** `true`
-
-From //kernel/params.gni:35
-
-### kernel_version_string
-Version string embedded in the kernel for `zx_system_get_version`.
-If set to the default "", a string is generated based on the
-Zircon git revision of the checkout.
-
-**Current value (from the default):** `""`
-
-From //kernel/lib/version/BUILD.gn:9
-
-### current_cpu
-
-**Current value (from the default):** `""`
-
-### enable_user_pci
-Enable userspace PCI and disable kernel PCI.
-
-**Current value (from the default):** `false`
-
-From //kernel/params.gni:41
-
-### 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:45
-
-### clang_tool_dir
-Directory where the Clang toolchain binaries ("clang", "llvm-nm", etc.) are
-found.  If this is "", then the behavior depends on $use_prebuilt_clang.
-This toolchain is expected to support both Fuchsia targets and the host.
-
-**Current value (from the default):** `""`
-
-From //public/gn/toolchain/clang.gni:14
-
-### 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):** `false`
-
-From //kernel/params.gni:53
-
-### malloc
-
-**Current value (from the default):** `"scudo"`
-
-From //third_party/ulib/musl/BUILD.gn:6
-
 ### zx
 *This must never be set as a build argument*.
 
@@ -93,6 +15,118 @@
 
 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
+
+### smp_max_cpus
+Maximum number of CPUs the kernel will run on (others will be ignored).
+
+**Current value (from the default):** `32`
+
+From //kernel/params.gni:7
+
+### symbol_level
+* 0 means no debugging information.
+* 1 means minimal debugging information sufficient to symbolize backtraces.
+* 2 means full debugging information for use with a symbolic debugger.
+
+**Current value (from the default):** `2`
+
+From //public/gn/config/levels.gni:20
+
+### 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
+
+### assert_level
+* 0 means no assertions, not even standard C `assert()`.
+* 1 means `ZX_ASSERT` but not `ZX_DEBUG_ASSERT`.
+* 2 means both `ZX_ASSERT` and  `ZX_DEBUG_ASSERT`.
+
+**Current value (from the default):** `2`
+
+From //public/gn/config/levels.gni:9
+
+### clang_tool_dir
+Directory where the Clang toolchain binaries ("clang", "llvm-nm", etc.) are
+found.  If this is "", then the behavior depends on $use_prebuilt_clang.
+This toolchain is expected to support both Fuchsia targets and the host.
+
+**Current value (from the default):** `""`
+
+From //public/gn/toolchain/clang.gni:14
+
+### 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:10
+
+### enable_lock_dep
+Enable kernel lock dependency tracking.
+
+**Current value (from the default):** `false`
+
+From //kernel/params.gni:32
+
+### 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):** `false`
+
+From //kernel/params.gni:53
+
+### enable_fair_scheduler
+Enable fair scheduler by default on all architectures.
+
+**Current value (from the default):** `true`
+
+From //kernel/params.gni:35
+
+### kernel_base
+
+**Current value (from the default):** `"0xffffffff80100000"`
+
+From //kernel/params.gni:20
+
+### 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
+
 ### variants
 List of "selectors" to request variant builds of certain targets.  Each
 selector specifies matching criteria and a chosen variant.  The first
@@ -311,16 +345,12 @@
 
 From //public/gn/toolchain/environment.gni:221
 
-### current_os
-
-**Current value (from the default):** `""`
-
-### enable_acpi_debug
-Enable debug output in the ACPI library (used by the ACPI bus driver).
+### detailed_scheduler_tracing
+Enable detailed scheduler traces.
 
 **Current value (from the default):** `false`
 
-From //third_party/lib/acpica/BUILD.gn:9
+From //kernel/params.gni:38
 
 ### ethernet_c
 This is used to temporarily enable building with the C driver
@@ -337,6 +367,52 @@
 
 From //system/core/netsvc/BUILD.gn:7
 
+### target_os
+
+**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
+
+### current_cpu
+
+**Current value (from the default):** `""`
+
+### enable_acpi_debug
+Enable debug output in the ACPI library (used by the ACPI bus driver).
+
+**Current value (from the default):** `false`
+
+From //third_party/lib/acpica/BUILD.gn:9
+
+### enable_kernel_debugging_features
+Whether to include various features (non-shipping, insecure, etc.) in the
+kernel build.
+
+**Current value (from the default):** `false`
+
+From //BUILD.gn:27
+
+### enable_user_pci
+Enable userspace PCI and disable kernel PCI.
+
+**Current value (from the default):** `false`
+
+From //kernel/params.gni:41
+
+### malloc
+
+**Current value (from the default):** `"scudo"`
+
+From //third_party/ulib/musl/BUILD.gn:6
+
 ### sysroot
 The `--sysroot` directory for host compilations.
 This can be a string, which only applies to $host_os-$host_cpu.
@@ -375,12 +451,12 @@
 
 From //public/gn/BUILDCONFIG.gn:20
 
-### use_goma
-Set to true to enable distributed compilation using Goma.
+### default_deps
+Defines the `//:default` target: what `ninja` with no arguments does.
 
-**Current value (from the default):** `false`
+**Current value (from the default):** `[":ids", ":images", ":tools"]`
 
-From //public/gn/toolchain/goma.gni:9
+From //BUILD.gn:19
 
 ### goma_dir
 Absolute directory containing the Goma source code.
@@ -389,11 +465,26 @@
 
 From //public/gn/toolchain/goma.gni:12
 
-### kernel_aspace_base
+### host_cpu
 
-**Current value (from the default):** `"0xffff000000000000"`
+**Current value (from the default):** `"x64"`
 
-From //kernel/params.gni:26
+### 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:45
+
+### kernel_version_string
+Version string embedded in the kernel for `zx_system_get_version`.
+If set to the default "", a string is generated based on the
+Zircon git revision of the checkout.
+
+**Current value (from the default):** `""`
+
+From //kernel/lib/version/BUILD.gn:9
 
 ### use_prebuilt_gcc
 If $gcc_tool_dir is "", then this controls how the GCC toolchain
@@ -404,39 +495,10 @@
 
 From //public/gn/toolchain/gcc.gni:9
 
-### default_deps
-Defines the `//:default` target: what `ninja` with no arguments does.
-
-**Current value (from the default):** `[":ids", ":images", ":tools"]`
-
-From //BUILD.gn:19
-
-### host_os
-
-**Current value (from the default):** `"linux"`
-
-### symbol_level
-* 0 means no debugging information.
-* 1 means minimal debugging information sufficient to symbolize backtraces.
-* 2 means full debugging information for use with a symbolic debugger.
-
-**Current value (from the default):** `2`
-
-From //public/gn/config/levels.gni:20
-
 ### target_cpu
 
 **Current value (from the default):** `""`
 
-### 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
-
 ### asan_default_options
 Default [AddressSanitizer](https://llvm.org/docs/AddressSanitizer.html)
 options (before the `ASAN_OPTIONS` environment variable is read at
@@ -450,28 +512,24 @@
 
 From //public/gn/config/instrumentation/BUILD.gn:13
 
-### 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:38
+From //public/gn/toolchain/c_toolchain.gni:17
 
-### 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_os
 
 **Current value (from the default):** `""`
 
-From //public/gn/toolchain/gcc.gni:17
+### host_os
 
-### host_cpu
-
-**Current value (from the default):** `"x64"`
+**Current value (from the default):** `"linux"`
 
 ### opt_level
 * -1 means really unoptimized (-O0), usually only build-tested and not run.
@@ -483,60 +541,3 @@
 
 From //public/gn/config/levels.gni:15
 
-### target_os
-
-**Current value (from the default):** `""`
-
-### use_ccache
-Set to true to enable compiling with ccache.
-
-**Current value (from the default):** `false`
-
-From //public/gn/toolchain/ccache.gni:9
-
-### assert_level
-* 0 means no assertions, not even standard C `assert()`.
-* 1 means `ZX_ASSERT` but not `ZX_DEBUG_ASSERT`.
-* 2 means both `ZX_ASSERT` and  `ZX_DEBUG_ASSERT`.
-
-**Current value (from the default):** `2`
-
-From //public/gn/config/levels.gni:9
-
-### enable_kernel_debugging_features
-Whether to include various features (non-shipping, insecure, etc.) in the
-kernel build.
-
-**Current value (from the default):** `false`
-
-From //BUILD.gn:27
-
-### enable_lock_dep
-Enable kernel lock dependency tracking.
-
-**Current value (from the default):** `false`
-
-From //kernel/params.gni:32
-
-### kernel_base
-
-**Current value (from the default):** `"0xffffffff00000000"`
-
-From //kernel/params.gni:18
-
-### smp_max_cpus
-
-**Current value (from the default):** `16`
-
-From //kernel/params.gni:10
-
-### 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
-
commit	7cda1faed9042e62f2a18cef71efa0ac1ee3d840	[log] [tgz]
author	docs-roller <docs-roller@fuchsia-infra.iam.gserviceaccount.com>	Mon Apr 22 22:37:50 2019 +0000
committer	CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>	Mon Apr 22 22:37:50 2019 +0000
tree	c842c017ffcd24e146c751aa53f1c1b3d5554b22
parent	0e0d4b392755eadf00e72ee4ed6ac80c31ffb59a [diff]