The ffx debug symbol-index
commands help
manage Fuchsia components’ debug symbols in your development environment.
Concepts
During development, debug symbols for a Fuchsia component are generated
as part of build artifacts. A file containing debug symbols has
.symbol-index.json
as a postfix (for example,
my-component.symbol-index.json
).
Registering a Fuchsia component's debug symbols in your development environment enables the following workflows:
- View the component's logs in symbolized format.
- Use the Fuchsia debugger to step through the code while the component is running on a device.
- Monitor the component's FIDL traffic on a device in real time.
In addition to registering locally generated debug symbols, you can also
configure your environment to retrieve debug symbols from an online storage
(for instance, Google Cloud Storage). Once an online storage is added in
your global symbol-index
configuration,
various Fuchsia debugging tools (such as ffx log
and
ffx debug connect
) can automatically
download and use the debug symbols available in the online storage.
In a Fuchsia development environment, a registration of debug symbols
often takes place in the background. Some Fuchsia tools are configured
to invoke the registration of debug symbols
(using ffx debug symbol-index add
)
upon detection of debug symbols, so you may never need to manually
register the debug symbols of your Fuchsia component during development.
For instance, if you're using Fuchsia's Bazel rules, the debug symbols get
registered automatically as part of the build. However, when necessary,
you could use the ffx debug symbol-index
commands to manage debug symbols directly.
List registered debug symbols
To view your global symbol-index
configuration, run the following command:
ffx debug symbol-index list
This command prints output similar to the following:
$ ffx debug symbol-index list
SymbolIndex {
includes: [
"/usr/alice/home/my-fuchsia-project/my-component.symbol-index.json",
],
build_id_dirs: [],
ids_txts: [],
gcs_flat: [
GcsFlat {
url: "gs://our-fuchsia-project/debug",
require_authentication: false,
},
],
debuginfod: []
}
Add a debuginfod symbol server
When working with third party binaries that are not built in the Fuchsia tree, you may be able to add a debuginfod server to fetch the symbols. Upstream distributions provide debuginfod servers, such as debuginfod.debian.net or "federated" servers, such as debuginfod.elfutils.org which will serve symbols from many different upstream sources. Check with your upstream source to find their debuginfod server, if they offer one. Often, these will be presented as environment variables, such as this:
export DEBUGINFOD_URLS="https://debuginfod.debian.net
To add a debuginfod server such as above to your symbol-index, use the following command:
ffx debug symbol-index add <URL>
Replace URL
with the URL for the debuginfod server you would like to add.
For example, to add Debian's debuginfod server, run the following command:
ffx debug symbol-index add https://debuginfod.debian.net
When the registration is successful, the command exits silently without output. Debugging tools will automatically query the server for symbols that cannot be found locally.
If you want to verify the registration, see List registered debug symbols.
Remove a debuginfod symbol server
To remove a debuginfod server from your global symbol-index
configuration, run
the following command:
ffx debug symbol-index remove <URL>
Replace URL
with the URL for the debuginfod server you would like to remove.
The example below removes the debian debuginfod server:
ffx debug symbol-index remove https://debuginfod.debian.net
Manually register local debug symbols
To register debug symbols in your environment, run the following command:
ffx debug symbol-index add <PATH_TO_DEBUG_SYMBOLS>
Replace PATH_TO_DEBUG_SYMBOLS
with an absolute path to a debug symbols
file.
The example below registers the debug symbols of the my-component
component:
$ ffx debug symbol-index add /usr/alice/home/my-fuchsia-project/my-component.symbol-index.json
When the registration is successful, the command exits silently without output.
If you want to verify the registration, see List registered debug symbols.
Remove registered local debug symbols
To remove debug symbols from your global symbol-index
configuration, run the
following command:
ffx debug symbol-index remove <PATH_TO_DEBUG_SYMBOLS>
Replace PATH_TO_DEBUG_SYMBOLS
with the exact path to a registered debug
symbols file to be removed.
The example below removes the debug symbols of the my-component
component:
$ ffx debug symbol-index remove /usr/alice/home/my-fuchsia-project/my-component.symbol-index.json
When the removal is successful, the command exits silently without output.
Clean up misplaced debug symbols
Deleting a registered debug symbols file on the host machine does not mean that
your global symbol-index
configuration also gets updated automatically.
To remove any stale paths (pointing to deleted debug symbols files) from
the global symbol-index
configuration, run the following command:
ffx debug symbol-index clean
For instance, if the /usr/alice/home/my-fuchsia-project
directory no longer
exists on the host machine, this command removes the
/usr/alice/home/my-fuchsia-project/my-component.symbol-index.json
entry from
the global symbol-index
configuration.