circuit::layouter::RegionColumn: Introduce TableTag variant

Co-authored-by: Avi Dessauer <avi.dessauer@platonic.systems>

halo2_proofs/src/circuit/layouter.rs

@@ -8,6 +8,8 @@ use ff::Field;
 
 pub use super::table_layouter::TableLayouter;
 use super::{Cell, RegionIndex, Value};
+#[cfg(feature = "unstable-dynamic-lookups")]
+use crate::plonk::TableTag;
 use crate::plonk::{Advice, Any, Assigned, Column, Error, Fixed, Instance, Selector};
 
 /// Helper trait for implementing a custom [`Layouter`].
@@ -15,7 +17,7 @@ use crate::plonk::{Advice, Any, Assigned, Column, Error, Fixed, Instance, Select
 /// This trait is used for implementing region assignments:
 ///
 /// ```ignore
-/// impl<'a, F: FieldExt, C: Chip<F>, CS: Assignment<F> + 'a> Layouter<C> for MyLayouter<'a, C, CS> {
+/// impl<'a, F: Field, C: Chip<F>, CS: Assignment<F> + 'a> Layouter<C> for MyLayouter<'a, C, CS> {
 ///     fn assign_region(
 ///         &mut self,
 ///         assignment: impl FnOnce(Region<'_, F, C>) -> Result<(), Error>,
@@ -127,6 +129,9 @@ pub enum RegionColumn {
     Column(Column<Any>),
     /// Virtual column representing a (boolean) selector
     Selector(Selector),
+    /// Virtual column used for storing dynamic table tags
+    #[cfg(feature = "unstable-dynamic-lookups")]
+    TableTag(TableTag),
 }
 
 impl From<Column<Any>> for RegionColumn {
@@ -141,13 +146,26 @@ impl From<Selector> for RegionColumn {
     }
 }
 
+#[cfg(feature = "unstable-dynamic-lookups")]
+impl From<TableTag> for RegionColumn {
+    fn from(table_tag: TableTag) -> RegionColumn {
+        RegionColumn::TableTag(table_tag)
+    }
+}
+
 impl Ord for RegionColumn {
     fn cmp(&self, other: &Self) -> cmp::Ordering {
         match (self, other) {
             (Self::Column(ref a), Self::Column(ref b)) => a.cmp(b),
             (Self::Selector(ref a), Self::Selector(ref b)) => a.0.cmp(&b.0),
-            (Self::Column(_), Self::Selector(_)) => cmp::Ordering::Less,
+            #[cfg(feature = "unstable-dynamic-lookups")]
+            (Self::TableTag(ref a), Self::TableTag(ref b)) => a.0.cmp(&b.0),
+            (Self::Column(_), _) => cmp::Ordering::Less,
             (Self::Selector(_), Self::Column(_)) => cmp::Ordering::Greater,
+            #[cfg(feature = "unstable-dynamic-lookups")]
+            (Self::TableTag(_), _) => cmp::Ordering::Greater,
+            #[cfg(feature = "unstable-dynamic-lookups")]
+            (_, Self::TableTag(_)) => cmp::Ordering::Less,
         }
     }
 }

halo2_proofs/src/dev/graph/layout.rs

@@ -113,6 +113,8 @@ impl CircuitLayout {
             let column: Column<Any> = match column {
                 RegionColumn::Column(col) => col,
                 RegionColumn::Selector(selector) => cs.selector_map[selector.0].into(),
+                #[cfg(feature = "unstable-dynamic-lookups")]
+                RegionColumn::TableTag(tag_col) => cs.dynamic_table_tag_map[tag_col.0].into(),
             };
             column.index()
                 + match column.column_type() {