Merge pull request #1704 from alexcrichton/skip-anyref

Fix anyref table export in empty modules

Author: alexcrichton

crates/cli-support/src/js/mod.rs

@@ -1152,7 +1152,6 @@ impl<'a> Context<'a> {
         }
         self.expose_uint32_memory();
         if self.config.anyref {
-            self.expose_anyref_table();
             self.global(
                 "
                 function getArrayJsValueFromWasm(ptr, len) {
@@ -1834,30 +1833,11 @@ impl<'a> Context<'a> {
         true
     }
 
-    fn expose_anyref_table(&mut self) {
-        assert!(self.config.anyref);
-        if !self.should_write_global("anyref_table") {
-            return;
-        }
-        let table = self
-            .module
-            .tables
-            .iter()
-            .find(|t| match t.kind {
-                walrus::TableKind::Anyref(_) => true,
-                _ => false,
-            })
-            .expect("failed to find anyref table in module")
-            .id();
-        self.module.exports.add("__wbg_anyref_table", table);
-    }
-
     fn expose_add_to_anyref_table(&mut self) -> Result<(), Error> {
         assert!(self.config.anyref);
         if !self.should_write_global("add_to_anyref_table") {
             return Ok(());
         }
-        self.expose_anyref_table();
         self.require_internal_export("__wbindgen_anyref_table_alloc")?;
         self.global(
             "
@@ -2640,8 +2620,6 @@ impl<'a> Context<'a> {
             }
 
             Intrinsic::InitAnyrefTable => {
-                self.expose_anyref_table();
-
                 // Grow the table to insert our initial values, and then also
                 // set the 0th slot to `undefined` since that's what we've
                 // historically used for our ABI which is that the index of 0

crates/cli-support/src/webidl/mod.rs

@@ -623,6 +623,24 @@ impl<'a> Context<'a> {
         if !self.anyref_enabled {
             return Ok(());
         }
+
+        // Make sure to export the `anyref` table for the JS bindings since it
+        // will need to be initialized. If it doesn't exist though then the
+        // module must not use it, so we skip it.
+        let table = self
+            .module
+            .tables
+            .iter()
+            .find(|t| match t.kind {
+                walrus::TableKind::Anyref(_) => true,
+                _ => false,
+            });
+        let table = match table {
+            Some(t) => t.id(),
+            None => return Ok(()),
+        };
+        self.module.exports.add("__wbg_anyref_table", table);
+
         let ty = self.module.types.add(&[], &[]);
         let (import, import_id) = self.module.add_import_func(
             PLACEHOLDER_MODULE,
@@ -640,6 +658,7 @@ impl<'a> Context<'a> {
             None => import,
         });
         self.bind_intrinsic(import_id, Intrinsic::InitAnyrefTable)?;
+
         Ok(())
     }