fixup

Author: guybedford

test/js_optimizer/applyDCEGraphRemovals-esm-output.js

@@ -9,3 +9,7 @@ import { memory, main as _main, used_export as _used_export, memory as wasmMemor
 export { fd_write_impl as fd_write, fd_close_impl as fd_close };
 
 export { _main };
+
+var HEAP32;
+
+export { HEAP32 };

test/js_optimizer/applyDCEGraphRemovals-esm.js

@@ -27,4 +27,8 @@ export {
 
 export { _main };
 
+// MODULARIZE=instance runtime exports (bare form) must be left untouched.
+var HEAP32;
+export { HEAP32 };
+
 // EXTRA_INFO: { "unusedImports": ["unused_import"], "unusedExports": ["unused_export", "__indirect_function_table"] }

test/js_optimizer/applyImportAndExportNameChanges-esm-output.js

@@ -7,3 +7,7 @@ import { memory, b as _main, c as _malloc, memory as wasmMemory } from "./a.out.
 export { fd_write_impl as d, fd_close_impl as e };
 
 export { _main };
+
+var HEAP32;
+
+export { HEAP32 };

test/js_optimizer/applyImportAndExportNameChanges-esm.js

@@ -23,4 +23,8 @@ export {
 // Re-export of a wasm export: the local name (_main) is never in the mapping.
 export { _main };
 
+// MODULARIZE=instance runtime export (bare form): never in the mapping.
+var HEAP32;
+export { HEAP32 };
+
 // EXTRA_INFO: { "mapping": { "main": "b", "malloc": "c", "fd_write": "d", "fd_close": "e" } }

test/js_optimizer/emitDCEGraph-esm.js

@@ -38,6 +38,12 @@ export {
 // root the underlying `main` export, not be treated as a wasm import.
 export { _main };
 
+// MODULARIZE=instance runtime exports. These are plain JS bindings, not wasm
+// import edges, and must be left untouched (bare `export {..}` form).
+var HEAP32;
+var baz = () => {};
+export { HEAP32, baz };
+
 // Top-level uses: root the memory export (via the alias) and one wasm export.
 wasmMemory.buffer;
 _used_export();

tools/acorn-optimizer.mjs

@@ -719,22 +719,22 @@ function emitDCEGraph(ast) {
         // top-level uses (that would root every export and defeat DCE).
         emptyOut(node);
       } else if (isExportSpecifierList(node)) {
-        // WASM_ESM_INTEGRATION emits two sourceless `export {..}` forms:
+        // Sourceless `export {..}` statements come in three forms:
         //   (a) JS functions sent to wasm:  export { _fd_write as fd_write };
         //   (b) re-exports of wasm exports: export { _main };
-        // (a) are the wasm imports; (b) are ordinary top-level uses that should
-        // root the underlying export (handled in the second pass), so only (a)
-        // is recorded and removed here.
-        let isImportEdge = false;
-        node.specifiers.forEach((spec) => {
-          if (wasmExportLocals.has(spec.local.name)) {
-            return; // (b) re-export of a wasm export
-          }
+        //   (c) runtime/library exports:    export { HEAP32, baz };
+        // Only (a) are wasm import edges (recorded and removed here). (b) and
+        // (c) are ordinary top-level uses left in place to root in the second
+        // pass. (a) is the only form written with an alias (`x as y`), which
+        // acorn represents with distinct local/exported nodes; bare specifiers
+        // reuse a single node for both sides.
+        const importEdges = node.specifiers.filter(
+          (spec) =>
+            spec.local !== spec.exported && !wasmExportLocals.has(spec.local.name),
+        );
+        if (importEdges.length) {
           // (a) `export { jsName as nativeName }` - jsName implements the import.
-          imports.push([spec.local.name, spec.exported.name]);
-          isImportEdge = true;
-        });
-        if (isImportEdge) {
+          importEdges.forEach((spec) => imports.push([spec.local.name, spec.exported.name]));
           foundWasmImportsAssign = true;
           emptyOut(node); // does not root; second pass ignores it
         }