kraid/isa: Specially handle small_constant_t

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41841>

src/panfrost/compiler/kraid/isa.rs

@@ -64,6 +64,12 @@ pub trait TryDecode<T>: Sized {
     fn try_decode(value: T, arch: u8) -> Result<Self, Self::Error>;
 }
 
+pub trait SmallConstantTable: TryDecode<u8> {
+    const TABLE_LEN: u8;
+    fn name(&self) -> &'static str;
+    fn const_value(&self) -> u32;
+}
+
 #[derive(Clone, Copy)]
 pub struct EncodedSrc<S: Copy> {
     pub encoded: u8,

src/panfrost/compiler/kraid/proc/isa/enums.rs

@@ -15,6 +15,7 @@ pub struct EnumValue {
     pub arch: ArchSet,
     pub canonical: bool,
     pub value: u8,
+    pub const_value: Option<u32>,
 }
 
 impl EnumValue {
@@ -38,6 +39,7 @@ impl EnumValue {
                 .get_u8_attr("value")
                 .ok_or(err("Enum value has no value"))?
                 .into(),
+            const_value: xml.get_u32_attr("const_value"),
         })
     }
 
@@ -245,6 +247,40 @@ impl Enum {
             });
         }
 
+        if self.name == "small_constant_t" {
+            let mut const_name_cases_ts = TokenStream2::new();
+            let mut const_value_cases_ts = TokenStream2::new();
+            for v in self.values.values() {
+                let v_name = &v.name;
+                let v_ident = &v.ident;
+                let const_value = v.const_value.unwrap();
+                const_name_cases_ts.extend(quote! {
+                    #e_ident::#v_ident => #v_name,
+                });
+                const_value_cases_ts.extend(quote! {
+                    #e_ident::#v_ident => #const_value,
+                });
+            }
+            let table_len = max_value + 1;
+            ts.extend(quote! {
+                impl SmallConstantTable for #e_ident {
+                    const TABLE_LEN: u8 = #table_len;
+
+                    fn name(&self) -> &'static str {
+                        match self {
+                            #const_name_cases_ts
+                        }
+                    }
+
+                    fn const_value(&self) -> u32 {
+                        match self {
+                            #const_value_cases_ts
+                        }
+                    }
+                }
+            });
+        }
+
         // Add a per-value arch array which we'll use for TryEncode/Decode
 
         if unique_values {

src/panfrost/compiler/kraid/proc/isa/xml.rs

@@ -7,6 +7,16 @@ use xml::attribute::OwnedAttribute;
 use xml::name::OwnedName;
 use xml::reader::{EventReader, XmlEvent};
 
+fn split_str_radix(s: &str) -> (&str, u32) {
+    if s.starts_with("0x") || s.starts_with("0X") {
+        (&s[2..], 16)
+    } else if s.starts_with("0b") || s.starts_with("0B") {
+        (&s[2..], 2)
+    } else {
+        (s, 10)
+    }
+}
+
 /// A very simpl DOM
 pub struct XmlElement {
     pub name: OwnedName,
@@ -73,7 +83,15 @@ impl XmlElement {
 
     pub fn get_u8_attr(&self, name: &str) -> Option<u8> {
         let s = self.attrs.get(name)?;
-        let u = u8::from_str_radix(s, 10).unwrap();
+        let (s, r) = split_str_radix(s);
+        let u = u8::from_str_radix(s, r).unwrap();
+        Some(u)
+    }
+
+    pub fn get_u32_attr(&self, name: &str) -> Option<u32> {
+        let s = self.attrs.get(name)?;
+        let (s, r) = split_str_radix(s);
+        let u = u32::from_str_radix(s, r).unwrap();
         Some(u)
     }