refactor: replace linkme with inventory

src/expr/core/Cargo.toml

@@ -40,8 +40,8 @@ either = "1"
 enum-as-inner = "0.6"
 futures-async-stream = { workspace = true }
 futures-util = "0.3"
+inventory = "0.3"
 itertools = "0.12"
-linkme = { version = "0.3", features = ["used_linker"] }
 md5 = "0.7"
 moka = { version = "0.12", features = ["sync"] }
 num-traits = "0.2"

src/expr/core/src/codegen.rs

@@ -15,5 +15,5 @@
 pub use async_trait::async_trait;
 pub use futures_async_stream::try_stream;
 pub use futures_util::stream::BoxStream;
+pub use inventory;
 pub use itertools::multizip;
-pub use linkme;

src/expr/core/src/sig/mod.rs

@@ -33,10 +33,10 @@ use crate::ExprError;
 /// The global registry of all function signatures.
 pub static FUNCTION_REGISTRY: LazyLock<FunctionRegistry> = LazyLock::new(|| {
     let mut map = FunctionRegistry::default();
-    tracing::info!("found {} functions", FUNCTIONS.len());
-    for f in FUNCTIONS {
-        map.insert(f());
+    for f in inventory::iter::<FuncSignBuilder> {
+        map.insert((f.0)());
     }
+    tracing::info!("found {} functions", map.len());
     map
 });
 
@@ -144,6 +144,11 @@ impl FunctionRegistry {
         (sig.type_infer)(args)
     }
 
+    /// Returns the number of function signatures in the registry.
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+
     /// Returns an iterator of all function signatures.
     pub fn iter(&self) -> impl Iterator<Item = &FuncSign> {
         self.0.values().flatten()
@@ -186,6 +191,11 @@ pub struct FuncSign {
     pub deprecated: bool,
 }
 
+/// A new type around a function that returns a [`FuncSign`]. Used for registering
+/// function signatures from `#[function]` attributes in the entire codebase.
+pub struct FuncSignBuilder(pub fn() -> FuncSign);
+inventory::collect!(FuncSignBuilder);
+
 impl fmt::Debug for FuncSign {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
@@ -457,7 +467,3 @@ pub enum FuncBuilder {
     },
     Udf,
 }
-
-/// A static distributed slice of functions defined by `#[function]`.
-#[linkme::distributed_slice]
-pub static FUNCTIONS: [fn() -> FuncSign];

src/expr/impl/Cargo.toml

@@ -33,7 +33,6 @@ hex = "0.4"
 icelake = { workspace = true }
 itertools = "0.12"
 jsonbb = "0.1.2"
-linkme = { version = "0.3", features = ["used_linker"] }
 md5 = "0.7"
 num-traits = "0.2"
 openssl = { version = "0.10", features = ["vendored"] }

src/expr/macro/src/gen.rs

@@ -162,7 +162,6 @@ impl FunctionAttr {
         let deprecated = self.deprecated;
 
         Ok(quote! {
-            #[risingwave_expr::codegen::linkme::distributed_slice(risingwave_expr::sig::FUNCTIONS)]
             fn #ctor_name() -> risingwave_expr::sig::FuncSign {
                 use risingwave_common::types::{DataType, DataTypeName};
                 use risingwave_expr::sig::{FuncSign, SigDataType, FuncBuilder};
@@ -177,6 +176,9 @@ impl FunctionAttr {
                     deprecated: #deprecated,
                 }
             }
+            risingwave_expr::codegen::inventory::submit! {
+                risingwave_expr::sig::FuncSignBuilder(#ctor_name)
+            }
         })
     }
 
@@ -652,7 +654,6 @@ impl FunctionAttr {
         let deprecated = self.deprecated;
 
         Ok(quote! {
-            #[risingwave_expr::codegen::linkme::distributed_slice(risingwave_expr::sig::FUNCTIONS)]
             fn #ctor_name() -> risingwave_expr::sig::FuncSign {
                 use risingwave_common::types::{DataType, DataTypeName};
                 use risingwave_expr::sig::{FuncSign, SigDataType, FuncBuilder};
@@ -672,6 +673,9 @@ impl FunctionAttr {
                     deprecated: #deprecated,
                 }
             }
+            risingwave_expr::codegen::inventory::submit! {
+                risingwave_expr::sig::FuncSignBuilder(#ctor_name)
+            }
         })
     }
 
@@ -984,7 +988,6 @@ impl FunctionAttr {
         let deprecated = self.deprecated;
 
         Ok(quote! {
-            #[risingwave_expr::codegen::linkme::distributed_slice(risingwave_expr::sig::FUNCTIONS)]
             fn #ctor_name() -> risingwave_expr::sig::FuncSign {
                 use risingwave_common::types::{DataType, DataTypeName};
                 use risingwave_expr::sig::{FuncSign, SigDataType, FuncBuilder};
@@ -999,6 +1002,9 @@ impl FunctionAttr {
                     deprecated: #deprecated,
                 }
             }
+            risingwave_expr::codegen::inventory::submit! {
+                risingwave_expr::sig::FuncSignBuilder(#ctor_name)
+            }
         })
     }
 

src/frontend/Cargo.toml

@@ -39,8 +39,8 @@ futures = { version = "0.3", default-features = false, features = ["alloc"] }
 futures-async-stream = { workspace = true }
 iana-time-zone = "0.1"
 icelake = { workspace = true }
+inventory = "0.3"
 itertools = "0.12"
-linkme = { version = "0.3", features = ["used_linker"] }
 maplit = "1"
 md5 = "0.7.0"
 memcomparable = "0.2"

src/frontend/macro/src/lib.rs

@@ -114,7 +114,6 @@ fn gen_sys_table(attr: Attr, item_fn: ItemFn) -> Result<TokenStream2> {
     let handle_error = return_result.then(|| quote!(?));
 
     Ok(quote! {
-        #[linkme::distributed_slice(crate::catalog::system_catalog::SYS_CATALOGS_SLICE)]
         #[no_mangle]    // to prevent duplicate schema.table name
         fn #gen_fn_name() -> crate::catalog::system_catalog::BuiltinCatalog {
             const _: () = {
@@ -136,6 +135,9 @@ fn gen_sys_table(attr: Attr, item_fn: ItemFn) -> Result<TokenStream2> {
                 }),
             })
         }
+        ::inventory::submit! {
+            crate::catalog::system_catalog::BuiltinCatalogBuilder(#gen_fn_name)
+        }
     })
 }
 
@@ -155,7 +157,6 @@ fn gen_sys_view(attr: Attr, item_struct: ItemStruct) -> Result<TokenStream2> {
     };
 
     Ok(quote! {
-        #[linkme::distributed_slice(crate::catalog::system_catalog::SYS_CATALOGS_SLICE)]
         #[no_mangle]    // to prevent duplicate schema.table name
         fn #gen_fn_name() -> crate::catalog::system_catalog::BuiltinCatalog {
             let fields = #struct_type::fields();
@@ -166,5 +167,8 @@ fn gen_sys_view(attr: Attr, item_struct: ItemStruct) -> Result<TokenStream2> {
                 columns: fields,
             })
         }
+        ::inventory::submit! {
+            crate::catalog::system_catalog::BuiltinCatalogBuilder(#gen_fn_name)
+        }
     })
 }

src/frontend/src/catalog/system_catalog/mod.rs

@@ -325,21 +325,23 @@ pub fn get_sys_views_in_schema(schema_name: &str) -> Vec<Arc<ViewCatalog>> {
         .collect()
 }
 
+/// A new type around a function that returns a [`BuiltinCatalog`]. Used for registering
+/// builtin catalogs from `#[system_catalog]` attributes in the `frontend` crate.
+pub(crate) struct BuiltinCatalogBuilder(pub fn() -> BuiltinCatalog);
+inventory::collect!(BuiltinCatalogBuilder);
+
 /// The global registry of all builtin catalogs.
 pub static SYS_CATALOGS: LazyLock<SystemCatalog> = LazyLock::new(|| {
-    tracing::info!("found {} catalogs", SYS_CATALOGS_SLICE.len());
-    assert!(SYS_CATALOGS_SLICE.len() <= MAX_SYS_CATALOG_NUM as usize);
-    let catalogs = SYS_CATALOGS_SLICE
-        .iter()
-        .map(|f| f())
+    let catalogs = inventory::iter::<BuiltinCatalogBuilder>
+        .into_iter()
+        .map(|b| (b.0)())
         .sorted_by_key(|c| c.full_name())
-        .collect();
+        .collect_vec();
+    assert!(catalogs.len() <= MAX_SYS_CATALOG_NUM as usize);
+    tracing::info!("found {} catalogs", catalogs.len());
     SystemCatalog { catalogs }
 });
 
-#[linkme::distributed_slice]
-pub static SYS_CATALOGS_SLICE: [fn() -> BuiltinCatalog];
-
 #[async_trait]
 impl SysCatalogReader for SysCatalogReaderImpl {
     async fn read_table(&self, table_id: &TableId) -> Result<DataChunk, BoxedError> {