it seems to, kinda work

ir/ir.rs

@@ -45,22 +45,19 @@ impl ItemsBuilder {
     /// Add the given item to to the graph and return the `Id` that it was
     /// assigned.
     pub fn add_item(&mut self, item: Item) -> Id {
-        // --- --- 8< --- ---
-        let dbg_clone = item.clone();
-        // --- --- 8< --- ---
-
         let id = item.id;
-        self.size_added += item.size;
-        self.items.insert(id, item);
-
-        let old_value = self.parsed.insert(id);
+        let size = item.size;
 
-        // --- --- 8< --- ---
-        if !old_value {
-            dbg!(dbg_clone);
-            panic!("value with id {:?} parsed into multiple items!", id);
+        match self.items.get_mut(&id) {
+            None => {
+                self.size_added += size;
+                self.items.insert(id, item);
+                self.parsed.insert(id);
+            }
+            Some(prev) => {
+                prev.size += size;
+            }
         }
-        // --- --- 8< --- ---
 
         id
     }

twiggy/tests/all/expectations/top_threaded_module

@@ -0,0 +1,13 @@
+ Shallow Bytes │ Shallow % │ Item
+───────────────┼───────────┼───────────────────────
+             8 ┊    18.18% ┊ wasm magic bytes
+             7 ┊    15.91% ┊ code[0]
+             6 ┊    13.64% ┊ code section headers
+             5 ┊    11.36% ┊ data[0]
+             3 ┊     6.82% ┊ type[0]: () -> nil
+             3 ┊     6.82% ┊ type section headers
+             3 ┊     6.82% ┊ memory[0]
+             3 ┊     6.82% ┊ memory section headers
+             3 ┊     6.82% ┊ "data count" section
+             3 ┊     6.82% ┊ data section headers
+            44 ┊   100.00% ┊ Σ [10 Total Rows]

twiggy/tests/all/fixtures/threads.wat

@@ -1,3 +1,4 @@
+;; Built with `wat2wasm --enable-bulk-memory --enable-threads`
 (module
  (memory $0 1 1)
  (data (i32.const 0) "")

twiggy/tests/all/top_tests.rs

@@ -80,43 +80,11 @@ test!(
 // Regression test for https://github.com/rustwasm/twiggy/issues/151
 test!(top_mono, "top", "./fixtures/mono.wasm", "-n", "10");
 
-// // Threaded modules should not cause a panic.
-// test!(
-// top_threaded_module,
-// "top",
-// "-n",
-// "25",
-// "./fixtures/threads.wasm"
-// );
-
-// DEV KTM: TEMPORARY WHILE REDUCING BINARY
-#[test]
-fn top_threaded_module() {
-    use std::process::Command;
-
-    let output = Command::new("cargo")
-        .arg("run")
-        .arg("--")
-        .arg("top")
-        .arg("-n")
-        .arg("25")
-        .arg("./fixtures/threads_test.wasm")
-        .current_dir(concat!(env!("CARGO_MANIFEST_DIR"), "/tests/all/"))
-        .output()
-        .unwrap();
-
-    assert_eq!(output.status.code(), Some(101),);
-    // assert!(output.status.success());
-
-    let stderr = String::from_utf8_lossy(&output.stderr);
-
-    let is_error_about_data_count_header = stderr
-        .lines()
-        .any(|l| l.contains("data count section headers"));
-    let contains_correct_panic = stderr.lines().any(|l| l.contains("ir.rs:61:13"));
-    assert!(
-        contains_correct_panic && is_error_about_data_count_header,
-        "incorrect panic!:\n{}",
-        stderr
-    );
-}
+// Threaded modules should not cause a panic.
+test!(
+    top_threaded_module,
+    "top",
+    "-n",
+    "25",
+    "./fixtures/threads.wasm"
+);