From 4c1d579db4f1778502f8defe217486a2cf1fdf5f Mon Sep 17 00:00:00 2001
From: Faith Ekstrand <faith.ekstrand@collabora.com>
Date: Wed, 27 May 2026 13:52:39 -0400
Subject: [PATCH] kraid/isa: Specially handle small_constant_t

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41841>
---
 src/panfrost/compiler/kraid/isa.rs            |  6 ++++
 src/panfrost/compiler/kraid/proc/isa/enums.rs | 36 +++++++++++++++++++
 src/panfrost/compiler/kraid/proc/isa/xml.rs   | 20 ++++++++++-
 3 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/src/panfrost/compiler/kraid/isa.rs b/src/panfrost/compiler/kraid/isa.rs
index db888882354..a8d2beb7506 100644
--- a/src/panfrost/compiler/kraid/isa.rs
+++ b/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,
diff --git a/src/panfrost/compiler/kraid/proc/isa/enums.rs b/src/panfrost/compiler/kraid/proc/isa/enums.rs
index 69458c13a56..82ad97d45cb 100644
--- a/src/panfrost/compiler/kraid/proc/isa/enums.rs
+++ b/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 {
diff --git a/src/panfrost/compiler/kraid/proc/isa/xml.rs b/src/panfrost/compiler/kraid/proc/isa/xml.rs
index ff54ca104b9..60d294b5368 100644
--- a/src/panfrost/compiler/kraid/proc/isa/xml.rs
+++ b/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)
     }