[meta] Map global TransformGroup to local TransformGroup indices;

cranelift/codegen/meta/src/cdsl/settings.rs

@@ -148,6 +148,14 @@ impl SettingGroup {
         }
         panic!("Should have found bool setting by name.");
     }
+
+    pub fn predicate_by_name(&self, name: &'static str) -> SettingPredicateNumber {
+        self.predicates
+            .iter()
+            .find(|pred| pred.name == name)
+            .unwrap_or_else(|| panic!("unknown predicate {}", name))
+            .number
+    }
 }
 
 /// This is the basic information needed to track the specific parts of a setting when building
@@ -209,10 +217,12 @@ struct ProtoPredicate {
     node: PredicateNode,
 }
 
+pub type SettingPredicateNumber = u8;
+
 pub struct Predicate {
     pub name: &'static str,
     node: PredicateNode,
-    pub number: u8,
+    pub number: SettingPredicateNumber,
 }
 
 impl Predicate {