rusticl: allow devices to be enabled by default

Reviewed-by: David Heidelberg <david@ixit.cz>
Acked-by: Eric Engestrom <eric@igalia.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31202>

meson_options.txt

@@ -160,6 +160,14 @@ option(
   description : 'build gallium "rusticl" OpenCL frontend.',
 )
 
+option(
+  'gallium-rusticl-enable-drivers',
+  type : 'array',
+  value : ['auto'],
+  description : 'List of gallium drivers for which rusticl will be enabled ' +
+                'by default',
+)
+
 option(
   'gallium-wgl-dll-name',
   type : 'string',

src/gallium/frontends/rusticl/mesa/pipe/device.rs

@@ -55,7 +55,11 @@ fn load_devs() -> impl Iterator<Item = PipeLoaderDevice> {
 fn get_enabled_devs() -> HashMap<String, u32> {
     let mut res = HashMap::new();
 
-    if let Ok(enabled_devs) = env::var("RUSTICL_ENABLE") {
+    // we require the type here as this list can be empty depending on the build options
+    let default_devs: &[&str] = &[];
+
+    // I wished we could use different iterators, but that's not really working out.
+    let enabled_devs = env::var("RUSTICL_ENABLE").unwrap_or(default_devs.join(","));
     let mut last_driver = None;
     for driver_str in enabled_devs.split(',') {
         if driver_str.is_empty() {
@@ -92,7 +96,6 @@ fn get_enabled_devs() -> HashMap<String, u32> {
     if res.contains_key("panfrost") {
         res.insert("panthor".to_owned(), res["panfrost"]);
     }
-    }
 
     res
 }

src/gallium/frontends/rusticl/meson.build

@@ -75,6 +75,13 @@ rusticl_args = [
   '-Aclippy::type_complexity',
 ]
 
+rusticl_drivers_enable = get_option('gallium-rusticl-enable-drivers')
+foreach driver : rusticl_drivers_enable
+  rusticl_args += [
+    '--cfg', 'rusticl_enable_' + driver,
+  ]
+endforeach
+
 if with_platform_x11
   rusticl_args += [
     '--cfg', 'glx',