From d9e93abfa4c503341eec15f0b69148bb0ff86709 Mon Sep 17 00:00:00 2001
From: y21 <30553356+y21@users.noreply.github.com>
Date: Wed, 27 Dec 2023 05:56:47 +0100
Subject: [PATCH] trace strings in localscopes and last bugfixes

---
 Cargo.lock                               |   1 +
 cli/src/cmd/eval.rs                      |   4 +-
 cli/src/cmd/repl.rs                      |   4 +-
 cli/src/cmd/run.rs                       |   4 +-
 crates/dash_middle/src/interner.rs       |  49 ++-
 crates/dash_vm/src/dispatch.rs           |  18 +-
 crates/dash_vm/src/frame.rs              |   3 +-
 crates/dash_vm/src/gc/interner.rs        | 507 -----------------------
 crates/dash_vm/src/gc/trace.rs           |  48 ++-
 crates/dash_vm/src/lib.rs                |   9 +
 crates/dash_vm/src/localscope.rs         |  13 +-
 crates/dash_vm/src/value/mod.rs          |   8 +-
 crates/dash_vm/src/value/object.rs       |  31 +-
 crates/dash_vm/src/value/primitive.rs    |  19 +-
 crates/dash_vm/src/value/regex.rs        |  13 +
 crates/dash_wasm/src/externalfunction.rs |   6 +-
 testrunner/.cargo/config.toml            |   4 +
 17 files changed, 175 insertions(+), 566 deletions(-)
 create mode 100644 testrunner/.cargo/config.toml

diff --git a/Cargo.lock b/Cargo.lock
index 640443f6..594a8433 100755
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -437,6 +437,7 @@ version = "0.3.0"
 dependencies = [
  "ahash",
  "bincode",
+ "dash_proc_macro",
  "dash_regex",
  "derive_more",
  "either",
diff --git a/cli/src/cmd/eval.rs b/cli/src/cmd/eval.rs
index cad29612..e13f94a5 100644
--- a/cli/src/cmd/eval.rs
+++ b/cli/src/cmd/eval.rs
@@ -17,10 +17,10 @@ pub fn eval(args: &ArgMatches) -> anyhow::Result<()> {
 
     match scope.eval(source, opt) {
         Ok(value) => println!("{}", format_value(value.root(&mut scope), &mut scope).unwrap()),
-        Err((EvalError::Exception(value), _)) => {
+        Err(EvalError::Exception(value)) => {
             println!("{}", format_value(value.root(&mut scope), &mut scope).unwrap())
         }
-        Err((EvalError::Middle(errs), _)) => println!("{}", errs.formattable(source, true)),
+        Err(EvalError::Middle(errs)) => println!("{}", errs.formattable(source, true)),
     };
 
     scope.process_async_tasks();
diff --git a/cli/src/cmd/repl.rs b/cli/src/cmd/repl.rs
index 6e23415a..99b512c8 100644
--- a/cli/src/cmd/repl.rs
+++ b/cli/src/cmd/repl.rs
@@ -21,10 +21,10 @@ pub fn repl() -> anyhow::Result<()> {
 
         match scope.eval(&input, OptLevel::Aggressive) {
             Ok(value) => println!("{}", format_value(value.root(&mut scope), &mut scope).unwrap()),
-            Err((EvalError::Exception(value), _)) => {
+            Err(EvalError::Exception(value)) => {
                 println!("{}", format_value(value.root(&mut scope), &mut scope).unwrap())
             }
-            Err((EvalError::Middle(errs), _)) => println!("{}", errs.formattable(&input, true)),
+            Err(EvalError::Middle(errs)) => println!("{}", errs.formattable(&input, true)),
         }
 
         scope.process_async_tasks();
diff --git a/cli/src/cmd/run.rs b/cli/src/cmd/run.rs
index 6f9a91c1..d87864f8 100644
--- a/cli/src/cmd/run.rs
+++ b/cli/src/cmd/run.rs
@@ -63,8 +63,8 @@ async fn inner(source: String, opt: OptLevel, quiet: bool, initial_gc_threshold:
     let mut scope = rt.vm_mut().scope();
     let value = match scope.eval(&source, opt) {
         Ok(val) => val.root(&mut scope),
-        Err((EvalError::Exception(val), _)) => val.root(&mut scope),
-        Err((EvalError::Middle(errs), _)) => {
+        Err(EvalError::Exception(val)) => val.root(&mut scope),
+        Err(EvalError::Middle(errs)) => {
             println!("{}", errs.formattable(&source, true));
             return Ok(());
         }
diff --git a/crates/dash_middle/src/interner.rs b/crates/dash_middle/src/interner.rs
index 3584569f..e554e474 100644
--- a/crates/dash_middle/src/interner.rs
+++ b/crates/dash_middle/src/interner.rs
@@ -1,3 +1,4 @@
+use std::cell::Cell;
 use std::hash::{BuildHasherDefault, Hash, Hasher};
 use std::rc::Rc;
 use std::{borrow, fmt};
@@ -256,9 +257,15 @@ pub mod sym {
     }
 }
 
+#[derive(Debug)]
+struct StringData {
+    visited: Cell<bool>,
+    value: Rc<str>,
+}
+
 #[derive(Default, Debug)]
 pub struct StringInterner {
-    store: Vec<Option<Rc<str>>>,
+    store: Vec<Option<StringData>>,
     mapping: hashbrown::HashMap<Rc<str>, RawSymbol, BuildHasherDefault<FxHasher>>,
     /// List of free indices in the storage
     free: Vec<RawSymbol>,
@@ -280,7 +287,10 @@ impl StringInterner {
             let s: Rc<str> = Rc::from(*s);
             debug_assert!(store.len() == index.0 as usize);
             mapping.insert(s.clone(), index.0);
-            store.push(Some(s));
+            store.push(Some(StringData {
+                visited: Cell::new(false),
+                value: s,
+            }));
         }
 
         Self {
@@ -291,7 +301,7 @@ impl StringInterner {
     }
 
     pub fn resolve(&self, symbol: Symbol) -> &str {
-        self.store[symbol.0 as usize].as_ref().unwrap()
+        self.store[symbol.0 as usize].as_ref().unwrap().value.as_ref()
     }
 
     // TODO: perf improvement idea: use interior mutability and allow calling with just a `&self`
@@ -305,13 +315,19 @@ impl StringInterner {
             RawEntryMut::Vacant(entry) => {
                 if let Some(id) = self.free.pop() {
                     let value: Rc<str> = Rc::from(value);
-                    self.store[id as usize] = Some(Rc::clone(&value));
+                    self.store[id as usize] = Some(StringData {
+                        value: Rc::clone(&value),
+                        visited: Cell::new(false),
+                    });
                     entry.insert_hashed_nocheck(hash, value, id);
                     Symbol(id)
                 } else {
                     let id = self.store.len() as RawSymbol;
                     let value: Rc<str> = Rc::from(value);
-                    self.store.push(Some(Rc::clone(&value)));
+                    self.store.push(Some(StringData {
+                        value: Rc::clone(&value),
+                        visited: Cell::new(false),
+                    }));
                     entry.insert_hashed_nocheck(hash, value, id);
                     Symbol(id)
                 }
@@ -337,10 +353,25 @@ impl StringInterner {
         self.intern(string.as_ref())
     }
 
-    // pub fn remove(&mut self, symbol: Symbol) {
-    //     self.storage[symbol.0 as usize] = None;
-    //     self.free.push(symbol.0);
-    // }
+    pub fn mark(&self, sym: Symbol) {
+        self.store[sym.0 as usize].as_ref().unwrap().visited.set(true);
+    }
+
+    /// You must mark all reachable symbols before calling this.
+    /// It won't cause undefined behavior if you don't (hence not unsafe), but it can lead to oddities such as panics.
+    pub fn sweep(&mut self) {
+        for i in 0..self.store.len() {
+            if let Some(data) = self.store[i].as_ref() {
+                if !data.visited.get() {
+                    self.mapping.remove(&data.value);
+                    self.store[i] = None;
+                    self.free.push(i as RawSymbol);
+                } else {
+                    data.visited.set(false);
+                }
+            }
+        }
+    }
 }
 
 type RawSymbol = u32;
diff --git a/crates/dash_vm/src/dispatch.rs b/crates/dash_vm/src/dispatch.rs
index 1829c5f7..b10771de 100755
--- a/crates/dash_vm/src/dispatch.rs
+++ b/crates/dash_vm/src/dispatch.rs
@@ -595,7 +595,7 @@ mod handlers {
     ) -> Result<Option<HandleResult>, Unrooted> {
         let (args, refs) = {
             let mut args = Vec::with_capacity(argc);
-            let mut refs = Vec::new();
+            // let mut refs = Vec::new();
 
             let len = cx.fetch_and_inc_ip();
             let spread_indices: SmallVec<[_; 4]> = (0..len).map(|_| cx.fetch_and_inc_ip()).collect();
@@ -605,9 +605,9 @@ mod handlers {
             if len == 0 {
                 // Fast path for no spread arguments
                 for value in iter {
-                    if let Value::Object(handle) = &value {
-                        refs.push(handle.clone());
-                    }
+                    // if let Value::Object(handle) = &value {
+                    //     refs.push(handle.clone());
+                    // }
 
                     args.push(value);
                 }
@@ -626,18 +626,18 @@ mod handlers {
                         }
                         indices_iter.next();
                     } else {
-                        if let Value::Object(handle) = &value {
-                            refs.push(handle.clone());
-                        }
+                        // if let Value::Object(handle) = &value {
+                        //     refs.push(handle.clone());
+                        // }
                         args.push(value);
                     }
                 }
             }
 
-            (args, refs)
+            (args, ())
         };
 
-        cx.scope.add_many(refs);
+        cx.scope.add_many(&args);
 
         let ret = if is_constructor {
             callee.construct(&mut cx, this, args)?
diff --git a/crates/dash_vm/src/frame.rs b/crates/dash_vm/src/frame.rs
index df802a95..6afb5602 100755
--- a/crates/dash_vm/src/frame.rs
+++ b/crates/dash_vm/src/frame.rs
@@ -31,7 +31,8 @@ pub struct Exports {
 unsafe impl Trace for Exports {
     fn trace(&self, cx: &mut TraceCtxt<'_>) {
         self.default.trace(cx);
-        for (_, v) in &self.named {
+        for (k, v) in &self.named {
+            k.trace(cx);
             v.trace(cx);
         }
     }
diff --git a/crates/dash_vm/src/gc/interner.rs b/crates/dash_vm/src/gc/interner.rs
index 5e484e5f..4851d852 100644
--- a/crates/dash_vm/src/gc/interner.rs
+++ b/crates/dash_vm/src/gc/interner.rs
@@ -1,508 +1 @@
 pub use dash_middle::interner::{sym, StringInterner, Symbol};
-
-// use std::borrow::Borrow;
-// use std::cell::Cell;
-// use std::hash::{BuildHasherDefault, Hash, Hasher};
-// use std::rc::Rc;
-
-// use hashbrown::hash_map::EntryRef;
-// use rustc_hash::{FxHashMap, FxHasher};
-
-// use super::trace::{Trace, TraceCtxt};
-
-// pub mod sym {
-//     use super::Symbol;
-
-//     // pub const VM_PREINTERNED_START: Symbol = Symbol(dash_middle::interner::sym::PRE_VM_INTERNED.raw() + 1);
-//     pub const VM_PREINTERNED_START: Symbol = Symbol(0);
-//     pub const VALUE: Symbol = VM_PREINTERNED_START;
-//     pub const NAME: Symbol = Symbol(VALUE.0 + 1);
-//     pub const PROTOTYPE: Symbol = Symbol(VALUE.0 + 2);
-//     pub const LENGTH: Symbol = Symbol(VALUE.0 + 3);
-//     pub const MESSAGE: Symbol = Symbol(VALUE.0 + 4);
-//     pub const STACK: Symbol = Symbol(VALUE.0 + 5);
-//     pub const ERROR: Symbol = Symbol(VALUE.0 + 6);
-//     pub const EMPTY: Symbol = Symbol(VALUE.0 + 7);
-//     pub const TO_STRING: Symbol = Symbol(VALUE.0 + 8);
-//     pub const VALUE_OF: Symbol = Symbol(VALUE.0 + 9);
-//     pub const UNDEFINED: Symbol = Symbol(VALUE.0 + 10);
-//     pub const LO_OBJECT: Symbol = Symbol(VALUE.0 + 11);
-//     pub const LO_BOOLEAN: Symbol = Symbol(VALUE.0 + 12);
-//     pub const LO_NUMBER: Symbol = Symbol(VALUE.0 + 13);
-//     pub const LO_BIGINT: Symbol = Symbol(VALUE.0 + 14);
-//     pub const LO_STRING: Symbol = Symbol(VALUE.0 + 15);
-//     pub const LO_SYMBOL: Symbol = Symbol(VALUE.0 + 16);
-//     pub const LO_FUNCTION: Symbol = Symbol(VALUE.0 + 17);
-//     pub const GET: Symbol = Symbol(VALUE.0 + 18);
-//     pub const LO_SET: Symbol = Symbol(VALUE.0 + 19);
-//     pub const WRITABLE: Symbol = Symbol(VALUE.0 + 20);
-//     pub const ENUMERABLE: Symbol = Symbol(VALUE.0 + 21);
-//     pub const CONFIGURABLE: Symbol = Symbol(VALUE.0 + 22);
-//     pub const PROTO: Symbol = Symbol(VALUE.0 + 23);
-//     pub const CONSTRUCTOR: Symbol = Symbol(VALUE.0 + 24);
-//     pub const DEFAULT: Symbol = Symbol(VALUE.0 + 25);
-//     pub const TRUE: Symbol = Symbol(VALUE.0 + 26);
-//     pub const FALSE: Symbol = Symbol(VALUE.0 + 27);
-//     pub const NULL: Symbol = Symbol(VALUE.0 + 28);
-//     pub const EVAL_ERROR: Symbol = Symbol(VALUE.0 + 29);
-//     pub const RANGE_ERROR: Symbol = Symbol(VALUE.0 + 30);
-//     pub const REFERENCE_ERROR: Symbol = Symbol(VALUE.0 + 31);
-//     pub const SYNTAX_ERROR: Symbol = Symbol(VALUE.0 + 32);
-//     pub const TYPE_ERROR: Symbol = Symbol(VALUE.0 + 33);
-//     pub const URI_ERROR: Symbol = Symbol(VALUE.0 + 34);
-//     pub const AGGREGATE_ERROR: Symbol = Symbol(VALUE.0 + 35);
-
-//     pub const FUNCTION: Symbol = Symbol(VALUE.0 + 35);
-//     pub const BIND: Symbol = Symbol(VALUE.0 + 36);
-//     pub const CALL: Symbol = Symbol(VALUE.0 + 37);
-//     pub const CREATE: Symbol = Symbol(VALUE.0 + 38);
-//     pub const KEYS: Symbol = Symbol(VALUE.0 + 39);
-//     pub const GET_OWN_PROPERTY_DESCRIPTOR: Symbol = Symbol(VALUE.0 + 40);
-//     pub const GET_OWN_PROPERTY_DESCRIPTORS: Symbol = Symbol(VALUE.0 + 41);
-//     pub const DEFINE_PROPERTY: Symbol = Symbol(VALUE.0 + 42);
-//     pub const ENTRIES: Symbol = Symbol(VALUE.0 + 43);
-//     pub const ASSIGN: Symbol = Symbol(VALUE.0 + 44);
-//     pub const OBJECT: Symbol = Symbol(VALUE.0 + 45);
-//     pub const HAS_OWN_PROPERTY: Symbol = Symbol(VALUE.0 + 46);
-//     pub const LOG: Symbol = Symbol(VALUE.0 + 47);
-//     pub const FLOOR: Symbol = Symbol(VALUE.0 + 48);
-//     pub const ABS: Symbol = Symbol(VALUE.0 + 49);
-//     pub const ACOS: Symbol = Symbol(VALUE.0 + 50);
-//     pub const ACOSH: Symbol = Symbol(VALUE.0 + 51);
-//     pub const ASIN: Symbol = Symbol(VALUE.0 + 52);
-//     pub const ASINH: Symbol = Symbol(VALUE.0 + 53);
-//     pub const ATAN: Symbol = Symbol(VALUE.0 + 54);
-//     pub const ATANH: Symbol = Symbol(VALUE.0 + 55);
-//     pub const ATAN2: Symbol = Symbol(VALUE.0 + 56);
-//     pub const CBRT: Symbol = Symbol(VALUE.0 + 57);
-//     pub const CEIL: Symbol = Symbol(VALUE.0 + 58);
-//     pub const CLZ32: Symbol = Symbol(VALUE.0 + 59);
-//     pub const COS: Symbol = Symbol(VALUE.0 + 60);
-//     pub const COSH: Symbol = Symbol(VALUE.0 + 61);
-//     pub const EXP: Symbol = Symbol(VALUE.0 + 62);
-//     pub const EXPM1: Symbol = Symbol(VALUE.0 + 63);
-//     pub const LOG1P: Symbol = Symbol(VALUE.0 + 64);
-//     pub const LOG10: Symbol = Symbol(VALUE.0 + 65);
-//     pub const LOG2: Symbol = Symbol(VALUE.0 + 66);
-//     pub const ROUND: Symbol = Symbol(VALUE.0 + 67);
-//     pub const SIN: Symbol = Symbol(VALUE.0 + 68);
-//     pub const SINH: Symbol = Symbol(VALUE.0 + 69);
-//     pub const SQRT: Symbol = Symbol(VALUE.0 + 70);
-//     pub const TAN: Symbol = Symbol(VALUE.0 + 71);
-//     pub const TANH: Symbol = Symbol(VALUE.0 + 72);
-//     pub const TRUNC: Symbol = Symbol(VALUE.0 + 73);
-//     pub const RANDOM: Symbol = Symbol(VALUE.0 + 74);
-//     pub const MAX: Symbol = Symbol(VALUE.0 + 75);
-//     pub const MIN: Symbol = Symbol(VALUE.0 + 76);
-//     pub const PI: Symbol = Symbol(VALUE.0 + 77);
-//     pub const IS_FINITE: Symbol = Symbol(VALUE.0 + 78);
-//     pub const IS_NA_N: Symbol = Symbol(VALUE.0 + 79);
-//     pub const IS_SAFE_INTEGER: Symbol = Symbol(VALUE.0 + 80);
-//     pub const NUMBER: Symbol = Symbol(VALUE.0 + 81);
-//     pub const TO_FIXED: Symbol = Symbol(VALUE.0 + 82);
-//     pub const BOOLEAN: Symbol = Symbol(VALUE.0 + 83);
-//     pub const FROM_CHAR_CODE: Symbol = Symbol(VALUE.0 + 84);
-//     pub const STRING: Symbol = Symbol(VALUE.0 + 85);
-//     pub const CHAR_AT: Symbol = Symbol(VALUE.0 + 86);
-//     pub const CHAR_CODE_AT: Symbol = Symbol(VALUE.0 + 87);
-//     pub const CONCAT: Symbol = Symbol(VALUE.0 + 88);
-//     pub const ENDS_WITH: Symbol = Symbol(VALUE.0 + 89);
-//     pub const STARTS_WITH: Symbol = Symbol(VALUE.0 + 90);
-//     pub const INCLUDES: Symbol = Symbol(VALUE.0 + 91);
-//     pub const INDEX_OF: Symbol = Symbol(VALUE.0 + 92);
-//     pub const LAST_INDEX_OF: Symbol = Symbol(VALUE.0 + 93);
-//     pub const PAD_END: Symbol = Symbol(VALUE.0 + 94);
-//     pub const PAD_START: Symbol = Symbol(VALUE.0 + 95);
-//     pub const REPEAT: Symbol = Symbol(VALUE.0 + 96);
-//     pub const REPLACE: Symbol = Symbol(VALUE.0 + 97);
-//     pub const REPLACE_ALL: Symbol = Symbol(VALUE.0 + 98);
-//     pub const SPLIT: Symbol = Symbol(VALUE.0 + 99);
-//     pub const TO_LOWER_CASE: Symbol = Symbol(VALUE.0 + 100);
-//     pub const TO_UPPER_CASE: Symbol = Symbol(VALUE.0 + 101);
-//     pub const BIG: Symbol = Symbol(VALUE.0 + 102);
-//     pub const BLINK: Symbol = Symbol(VALUE.0 + 103);
-//     pub const BOLD: Symbol = Symbol(VALUE.0 + 104);
-//     pub const FIXED: Symbol = Symbol(VALUE.0 + 105);
-//     pub const ITALICS: Symbol = Symbol(VALUE.0 + 106);
-//     pub const STRIKE: Symbol = Symbol(VALUE.0 + 107);
-//     pub const SUB: Symbol = Symbol(VALUE.0 + 108);
-//     pub const SUP: Symbol = Symbol(VALUE.0 + 109);
-//     pub const FONTCOLOR: Symbol = Symbol(VALUE.0 + 110);
-//     pub const FONTSIZE: Symbol = Symbol(VALUE.0 + 111);
-//     pub const LINK: Symbol = Symbol(VALUE.0 + 112);
-//     pub const TRIM: Symbol = Symbol(VALUE.0 + 113);
-//     pub const TRIM_START: Symbol = Symbol(VALUE.0 + 114);
-//     pub const TRIM_END: Symbol = Symbol(VALUE.0 + 115);
-//     pub const SUBSTR: Symbol = Symbol(VALUE.0 + 116);
-//     pub const SUBSTRING: Symbol = Symbol(VALUE.0 + 117);
-//     pub const FROM: Symbol = Symbol(VALUE.0 + 118);
-//     pub const IS_ARRAY: Symbol = Symbol(VALUE.0 + 119);
-//     pub const ARRAY: Symbol = Symbol(VALUE.0 + 120);
-//     pub const JOIN: Symbol = Symbol(VALUE.0 + 121);
-//     pub const VALUES: Symbol = Symbol(VALUE.0 + 122);
-//     pub const AT: Symbol = Symbol(VALUE.0 + 123);
-//     pub const EVERY: Symbol = Symbol(VALUE.0 + 124);
-//     pub const SOME: Symbol = Symbol(VALUE.0 + 125);
-//     pub const FILL: Symbol = Symbol(VALUE.0 + 126);
-//     pub const FILTER: Symbol = Symbol(VALUE.0 + 127);
-//     pub const REDUCE: Symbol = Symbol(VALUE.0 + 128);
-//     pub const FIND: Symbol = Symbol(VALUE.0 + 129);
-//     pub const FIND_INDEX: Symbol = Symbol(VALUE.0 + 130);
-//     pub const FLAT: Symbol = Symbol(VALUE.0 + 131);
-//     pub const FOR_EACH: Symbol = Symbol(VALUE.0 + 132);
-//     pub const LO_MAP: Symbol = Symbol(VALUE.0 + 133);
-//     pub const POP: Symbol = Symbol(VALUE.0 + 134);
-//     pub const PUSH: Symbol = Symbol(VALUE.0 + 135);
-//     pub const REVERSE: Symbol = Symbol(VALUE.0 + 136);
-//     pub const SHIFT: Symbol = Symbol(VALUE.0 + 137);
-//     pub const SORT: Symbol = Symbol(VALUE.0 + 138);
-//     pub const UNSHIFT: Symbol = Symbol(VALUE.0 + 139);
-//     pub const SLICE: Symbol = Symbol(VALUE.0 + 140);
-//     pub const NEXT: Symbol = Symbol(VALUE.0 + 141);
-//     pub const ASYNC_ITERATOR: Symbol = Symbol(VALUE.0 + 142);
-//     pub const HAS_INSTANCE: Symbol = Symbol(VALUE.0 + 143);
-//     pub const ITERATOR: Symbol = Symbol(VALUE.0 + 144);
-//     pub const MATCH: Symbol = Symbol(VALUE.0 + 145);
-//     pub const MATCH_ALL: Symbol = Symbol(VALUE.0 + 146);
-//     pub const SEARCH: Symbol = Symbol(VALUE.0 + 147);
-//     pub const SPECIES: Symbol = Symbol(VALUE.0 + 148);
-//     pub const TO_PRIMITIVE: Symbol = Symbol(VALUE.0 + 149);
-//     pub const TO_STRING_TAG: Symbol = Symbol(VALUE.0 + 150);
-//     pub const UNSCOPABLES: Symbol = Symbol(VALUE.0 + 151);
-//     pub const SYMBOL: Symbol = Symbol(VALUE.0 + 152);
-//     pub const ARRAY_BUFFER: Symbol = Symbol(VALUE.0 + 153);
-//     pub const BYTE_LENGTH: Symbol = Symbol(VALUE.0 + 154);
-//     pub const UINT8ARRAY: Symbol = Symbol(VALUE.0 + 155);
-//     pub const INT8ARRAY: Symbol = Symbol(VALUE.0 + 156);
-//     pub const UINT16ARRAY: Symbol = Symbol(VALUE.0 + 157);
-//     pub const INT16ARRAY: Symbol = Symbol(VALUE.0 + 158);
-//     pub const UINT32ARRAY: Symbol = Symbol(VALUE.0 + 159);
-//     pub const INT32ARRAY: Symbol = Symbol(VALUE.0 + 160);
-//     pub const FLOAT32ARRAY: Symbol = Symbol(VALUE.0 + 161);
-//     pub const FLOAT64ARRAY: Symbol = Symbol(VALUE.0 + 162);
-//     pub const RESOLVE: Symbol = Symbol(VALUE.0 + 163);
-//     pub const REJECT: Symbol = Symbol(VALUE.0 + 164);
-//     pub const PROMISE: Symbol = Symbol(VALUE.0 + 165);
-//     pub const THEN: Symbol = Symbol(VALUE.0 + 166);
-//     pub const SET: Symbol = Symbol(VALUE.0 + 167);
-//     pub const ADD: Symbol = Symbol(VALUE.0 + 168);
-//     pub const HAS: Symbol = Symbol(VALUE.0 + 169);
-//     pub const DELETE: Symbol = Symbol(VALUE.0 + 170);
-//     pub const CLEAR: Symbol = Symbol(VALUE.0 + 171);
-//     pub const SIZE: Symbol = Symbol(VALUE.0 + 172);
-//     pub const MAP: Symbol = Symbol(VALUE.0 + 173);
-//     pub const REG_EXP: Symbol = Symbol(VALUE.0 + 174);
-//     pub const TEST: Symbol = Symbol(VALUE.0 + 175);
-//     pub const EXEC: Symbol = Symbol(VALUE.0 + 176);
-//     pub const NOW: Symbol = Symbol(VALUE.0 + 177);
-//     pub const DATE: Symbol = Symbol(VALUE.0 + 178);
-//     pub const PARSE: Symbol = Symbol(VALUE.0 + 179);
-//     pub const PARSE_FLOAT: Symbol = Symbol(VALUE.0 + 180);
-//     pub const PARSE_INT: Symbol = Symbol(VALUE.0 + 181);
-//     pub const CONSOLE: Symbol = Symbol(VALUE.0 + 182);
-//     pub const MATH: Symbol = Symbol(VALUE.0 + 183);
-//     pub const JSON: Symbol = Symbol(VALUE.0 + 184);
-//     pub const IS_CONCAT_SPREADABLE: Symbol = Symbol(VALUE.0 + 185);
-//     pub const DONE: Symbol = Symbol(VALUE.0 + 186);
-//     pub const ZERO: Symbol = Symbol(VALUE.0 + 187);
-//     pub const ONE: Symbol = Symbol(VALUE.0 + 188);
-//     pub const COMMA: Symbol = Symbol(VALUE.0 + 189);
-
-//     pub const PREINTERNED: &[(&str, Symbol)] = &[
-//         ("value", VALUE),
-//         ("name", NAME),
-//         ("prototype", PROTOTYPE),
-//         ("length", LENGTH),
-//         ("message", MESSAGE),
-//         ("stack", STACK),
-//         ("Error", ERROR),
-//         ("", EMPTY),
-//         ("toString", TO_STRING),
-//         ("valueOf", VALUE_OF),
-//         ("undefined", UNDEFINED),
-//         ("object", LO_OBJECT),
-//         ("boolean", LO_BOOLEAN),
-//         ("number", LO_NUMBER),
-//         ("bigInt", LO_BIGINT),
-//         ("string", LO_STRING),
-//         ("symbol", LO_SYMBOL),
-//         ("function", LO_FUNCTION),
-//         ("get", GET),
-//         ("set", LO_SET),
-//         ("writable", WRITABLE),
-//         ("enumerable", ENUMERABLE),
-//         ("configurable", CONFIGURABLE),
-//         ("__proto__", PROTO),
-//         ("constructor", CONSTRUCTOR),
-//         ("default", DEFAULT),
-//         ("true", TRUE),
-//         ("false", FALSE),
-//         ("null", NULL),
-//         ("EvalError", EVAL_ERROR),
-//         ("RangeError", RANGE_ERROR),
-//         ("ReferenceError", REFERENCE_ERROR),
-//         ("SyntaxError", SYNTAX_ERROR),
-//         ("TypeError", TYPE_ERROR),
-//         ("URIError", URI_ERROR),
-//         ("AggregateError", AGGREGATE_ERROR),
-//         ("Function", FUNCTION),
-//         ("bind", BIND),
-//         ("call", CALL),
-//         ("create", CREATE),
-//         ("keys", KEYS),
-//         ("getOwnPropertyDescriptor", GET_OWN_PROPERTY_DESCRIPTOR),
-//         ("getOwnPropertyDescriptors", GET_OWN_PROPERTY_DESCRIPTORS),
-//         ("defineProperty", DEFINE_PROPERTY),
-//         ("entries", ENTRIES),
-//         ("assign", ASSIGN),
-//         ("Object", OBJECT),
-//         ("hasOwnProperty", HAS_OWN_PROPERTY),
-//         ("log", LOG),
-//         ("floor", FLOOR),
-//         ("abs", ABS),
-//         ("acos", ACOS),
-//         ("acosh", ACOSH),
-//         ("asin", ASIN),
-//         ("asinh", ASINH),
-//         ("atan", ATAN),
-//         ("atanh", ATANH),
-//         ("atan2", ATAN2),
-//         ("cbrt", CBRT),
-//         ("ceil", CEIL),
-//         ("clz32", CLZ32),
-//         ("cos", COS),
-//         ("cosh", COSH),
-//         ("exp", EXP),
-//         ("expm1", EXPM1),
-//         ("log1p", LOG1P),
-//         ("log10", LOG10),
-//         ("log2", LOG2),
-//         ("round", ROUND),
-//         ("sin", SIN),
-//         ("sinh", SINH),
-//         ("sqrt", SQRT),
-//         ("tan", TAN),
-//         ("tanh", TANH),
-//         ("trunc", TRUNC),
-//         ("random", RANDOM),
-//         ("max", MAX),
-//         ("min", MIN),
-//         ("PI", PI),
-//         ("isFinite", IS_FINITE),
-//         ("isNaN", IS_NA_N),
-//         ("isSafeInteger", IS_SAFE_INTEGER),
-//         ("Number", NUMBER),
-//         ("toFixed", TO_FIXED),
-//         ("Boolean", BOOLEAN),
-//         ("fromCharCode", FROM_CHAR_CODE),
-//         ("String", STRING),
-//         ("charAt", CHAR_AT),
-//         ("charCodeAt", CHAR_CODE_AT),
-//         ("concat", CONCAT),
-//         ("endsWith", ENDS_WITH),
-//         ("startsWith", STARTS_WITH),
-//         ("includes", INCLUDES),
-//         ("indexOf", INDEX_OF),
-//         ("lastIndexOf", LAST_INDEX_OF),
-//         ("padEnd", PAD_END),
-//         ("padStart", PAD_START),
-//         ("repeat", REPEAT),
-//         ("replace", REPLACE),
-//         ("replaceAll", REPLACE_ALL),
-//         ("split", SPLIT),
-//         ("toLowerCase", TO_LOWER_CASE),
-//         ("toUpperCase", TO_UPPER_CASE),
-//         ("big", BIG),
-//         ("blink", BLINK),
-//         ("bold", BOLD),
-//         ("fixed", FIXED),
-//         ("italics", ITALICS),
-//         ("strike", STRIKE),
-//         ("sub", SUB),
-//         ("sup", SUP),
-//         ("fontcolor", FONTCOLOR),
-//         ("fontsize", FONTSIZE),
-//         ("link", LINK),
-//         ("trim", TRIM),
-//         ("trimStart", TRIM_START),
-//         ("trimEnd", TRIM_END),
-//         ("substr", SUBSTR),
-//         ("substring", SUBSTRING),
-//         ("from", FROM),
-//         ("isArray", IS_ARRAY),
-//         ("Array", ARRAY),
-//         ("join", JOIN),
-//         ("values", VALUES),
-//         ("at", AT),
-//         ("every", EVERY),
-//         ("some", SOME),
-//         ("fill", FILL),
-//         ("filter", FILTER),
-//         ("reduce", REDUCE),
-//         ("find", FIND),
-//         ("findIndex", FIND_INDEX),
-//         ("flat", FLAT),
-//         ("forEach", FOR_EACH),
-//         ("map", LO_MAP),
-//         ("pop", POP),
-//         ("push", PUSH),
-//         ("reverse", REVERSE),
-//         ("shift", SHIFT),
-//         ("sort", SORT),
-//         ("unshift", UNSHIFT),
-//         ("slice", SLICE),
-//         ("next", NEXT),
-//         ("asyncIterator", ASYNC_ITERATOR),
-//         ("hasInstance", HAS_INSTANCE),
-//         ("iterator", ITERATOR),
-//         ("match", MATCH),
-//         ("matchAll", MATCH_ALL),
-//         ("search", SEARCH),
-//         ("species", SPECIES),
-//         ("toPrimitive", TO_PRIMITIVE),
-//         ("toStringTag", TO_STRING_TAG),
-//         ("unscopables", UNSCOPABLES),
-//         ("Symbol", SYMBOL),
-//         ("ArrayBuffer", ARRAY_BUFFER),
-//         ("byteLength", BYTE_LENGTH),
-//         ("Uint8Array", UINT8ARRAY),
-//         ("Int8Array", INT8ARRAY),
-//         ("Uint16Array", UINT16ARRAY),
-//         ("Int16Array", INT16ARRAY),
-//         ("Uint32Array", UINT32ARRAY),
-//         ("Int32Array", INT32ARRAY),
-//         ("Float32Array", FLOAT32ARRAY),
-//         ("Float64Array", FLOAT64ARRAY),
-//         ("resolve", RESOLVE),
-//         ("reject", REJECT),
-//         ("Promise", PROMISE),
-//         ("then", THEN),
-//         ("Set", SET),
-//         ("add", ADD),
-//         ("has", HAS),
-//         ("delete", DELETE),
-//         ("clear", CLEAR),
-//         ("size", SIZE),
-//         ("Map", MAP),
-//         ("RegExp", REG_EXP),
-//         ("test", TEST),
-//         ("exec", EXEC),
-//         ("now", NOW),
-//         ("Date", DATE),
-//         ("parse", PARSE),
-//         ("parseFloat", PARSE_FLOAT),
-//         ("parseInt", PARSE_INT),
-//         ("console", CONSOLE),
-//         ("Math", MATH),
-//         ("JSON", JSON),
-//         ("isConcatSpreadable", IS_CONCAT_SPREADABLE),
-//         ("done", DONE),
-//         ("0", ZERO),
-//         ("1", ONE),
-//         (",", COMMA),
-//     ];
-// }
-
-// fn fxhash(s: &str) -> u64 {
-//     let mut hasher = FxHasher::default();
-//     s.hash(&mut hasher);
-//     hasher.finish()
-// }
-
-// pub struct StringData {
-//     string: Rc<str>,
-// }
-
-// pub struct StringInterner {
-//     storage: Vec<Option<StringData>>,
-//     mapping: hashbrown::HashMap<Rc<str>, Symbol, BuildHasherDefault<FxHasher>>,
-//     /// List of free indices in the storage
-//     free: Vec<RawSymbol>,
-// }
-
-// impl StringInterner {
-//     pub fn new() -> Self {
-//         let mut storage = Vec::new();
-//         let mut mapping = hashbrown::HashMap::default();
-
-//         for (name, sym) in sym::PREINTERNED {
-//             let string = Rc::from(*name);
-//             debug_assert_eq!(sym.0, storage.len() as RawSymbol);
-//             storage.push(Some(StringData { string }));
-//         }
-
-//         Self {
-//             storage,
-//             mapping,
-//             free: Vec::new(),
-//         }
-//     }
-
-//     pub fn intern(&mut self, string: impl Borrow<str>) -> Symbol {
-//         let string = string.borrow();
-//         let hash = fxhash(string);
-//         match self.mapping.entry_ref(string) {
-//             EntryRef::Occupied(occ) => occ.get().clone(),
-//             EntryRef::Vacant(vac) => {
-//                 if let Some(id) = self.free.pop() {
-//                     self.storage[id as usize] = Some(StringData {
-//                         string: Rc::from(string),
-//                     });
-//                     vac.insert(Symbol(id));
-//                     Symbol(id)
-//                 } else {
-//                     let id: RawSymbol = self.storage.len().try_into().expect("too many strings");
-//                     let string = Rc::from(string);
-//                     self.storage.push(Some(StringData { string }));
-//                     vac.insert(Symbol(id));
-//                     Symbol(id)
-//                 }
-//             }
-//         }
-//     }
-
-//     pub fn intern_usize(&mut self, val: usize) -> Symbol {
-//         // for now this just calls `intern`, but we might want to specialize this
-//         let string = val.to_string();
-//         self.intern(string.as_ref())
-//     }
-
-//     pub fn intern_isize(&mut self, val: isize) -> Symbol {
-//         // for now this just calls `intern`, but we might want to specialize this
-//         let string = val.to_string();
-//         self.intern(string.as_ref())
-//     }
-
-//     pub fn intern_char(&mut self, val: char) -> Symbol {
-//         // for now this just calls `intern`, but we might want to specialize this
-//         let string = val.to_string();
-//         self.intern(string.as_ref())
-//     }
-
-//     // pub fn remove(&mut self, symbol: Symbol) {
-//     //     self.storage[symbol.0 as usize] = None;
-//     //     self.free.push(symbol.0);
-//     // }
-
-//     pub fn resolve(&mut self, symbol: Symbol) -> &str {
-//         &self.storage[symbol.0 as usize]
-//             .as_ref()
-//             .expect("tombstone symbol")
-//             .string
-//     }
-// }
-
-// type RawSymbol = u32;
-
-// #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-// pub struct Symbol(RawSymbol);
-
-// impl Symbol {}
-
-// unsafe impl Trace for Symbol {
-//     fn trace(&self, cx: &mut TraceCtxt<'_>) {
-//         todo!();
-//     }
-// }
-
-// // TODO: implement Trace for StringInterner which marks the preinterned strings
diff --git a/crates/dash_vm/src/gc/trace.rs b/crates/dash_vm/src/gc/trace.rs
index 10fc017b..f0eeaf75 100644
--- a/crates/dash_vm/src/gc/trace.rs
+++ b/crates/dash_vm/src/gc/trace.rs
@@ -3,7 +3,7 @@ use std::collections::{HashMap, HashSet};
 use std::path::{Path, PathBuf};
 use std::rc::Rc;
 
-use dash_middle::compiler::constant::Function;
+use dash_middle::compiler::constant::{Constant, Function};
 
 use crate::value::function::native::CallContext;
 use crate::value::primitive::{Null, Number, Symbol, Undefined};
@@ -14,13 +14,17 @@ use crate::value::Unrooted;
 use super::interner::StringInterner;
 
 pub struct TraceCtxt<'vm> {
-    interner: &'vm mut StringInterner,
+    pub interner: &'vm mut StringInterner,
 }
 
 impl<'vm> TraceCtxt<'vm> {
     pub fn new(interner: &'vm mut StringInterner) -> Self {
         Self { interner }
     }
+
+    pub fn mark_symbol(&self, symbol: dash_middle::interner::Symbol) {
+        self.interner.mark(symbol);
+    }
 }
 
 /// # Safety
@@ -113,12 +117,47 @@ macro_rules! unsafe_empty_trace {
 
 unsafe impl Trace for dash_middle::interner::Symbol {
     fn trace(&self, cx: &mut TraceCtxt<'_>) {
-        todo!("mark symbol")
+        cx.mark_symbol(*self);
+    }
+}
+
+unsafe impl Trace for dash_middle::compiler::constant::Function {
+    fn trace(&self, cx: &mut TraceCtxt<'_>) {
+        let Self {
+            name,
+            buffer: _,
+            ty: _,
+            locals: _,
+            params: _,
+            constants,
+            externals: _,
+            r#async: _,
+            rest_local: _,
+            poison_ips: _,
+            source: _,
+            debug_symbols: _,
+        } = self;
+        name.trace(cx);
+        constants.trace(cx);
+    }
+}
+
+unsafe impl Trace for Constant {
+    fn trace(&self, cx: &mut TraceCtxt<'_>) {
+        match self {
+            Constant::Number(_) => {}
+            Constant::String(sym) => sym.trace(cx),
+            Constant::Identifier(sym) => sym.trace(cx),
+            Constant::Boolean(_) => {}
+            Constant::Function(func) => func.trace(cx),
+            Constant::Regex(_, _, sym) => sym.trace(cx),
+            Constant::Null => {}
+            Constant::Undefined => {}
+        }
     }
 }
 
 unsafe_empty_trace!(
-    Function,
     usize,
     u8,
     f64,
@@ -128,7 +167,6 @@ unsafe_empty_trace!(
     Null,
     // Symbol,
     Number,
-    RegExpInner,
     TypedArrayKind,
     PathBuf,
     Path,
diff --git a/crates/dash_vm/src/lib.rs b/crates/dash_vm/src/lib.rs
index f5b6ef37..028450cb 100644
--- a/crates/dash_vm/src/lib.rs
+++ b/crates/dash_vm/src/lib.rs
@@ -1406,6 +1406,9 @@ impl Vm {
         sweep.in_scope(|| unsafe { self.gc.sweep() });
         debug!("object count after sweep: {}", self.gc.node_count());
 
+        debug!("sweep interner");
+        self.interner.sweep();
+
         // Adjust GC threshold
         let new_object_count = self.gc.node_count();
         self.gc_object_threshold = new_object_count * 2;
@@ -1414,6 +1417,12 @@ impl Vm {
 
     fn trace_roots(&mut self) {
         let mut cx = TraceCtxt::new(&mut self.interner);
+        
+        debug!("trace preinterned symbols");
+        for (_, sym) in sym::PREINTERNED {
+            sym.trace(&mut cx);
+        }
+
         debug!("trace frames");
         self.frames.trace(&mut cx);
         debug!("trace async tasks");
diff --git a/crates/dash_vm/src/localscope.rs b/crates/dash_vm/src/localscope.rs
index 95ee186f..85230b7e 100755
--- a/crates/dash_vm/src/localscope.rs
+++ b/crates/dash_vm/src/localscope.rs
@@ -91,6 +91,7 @@ unsafe impl Trace for LocalScopeList {
         for ptr in list {
             let data = unsafe { ptr.as_ref() };
             data.refs.trace(cx);
+            data.strings.trace(cx);
         }
     }
 }
@@ -157,12 +158,20 @@ impl<'vm> LocalScope<'vm> {
                 self.add_ref(o.inner.clone());
                 self.add_ref(o.into_dyn());
             }
+            Value::String(s) => {
+                self.scope_data_mut().strings.push(s.sym());
+            }
+            Value::Symbol(s) => {
+                self.scope_data_mut().strings.push(s.sym());
+            }
             _ => {}
         }
     }
 
-    pub fn add_many(&mut self, mut v: Vec<Handle<dyn Object>>) {
-        self.scope_data_mut().refs.append(&mut v);
+    pub fn add_many(&mut self, v: &[Value]) {
+        for val in v {
+            self.add_value(val.clone());
+        }
     }
 
     /// Registers an object and roots it.
diff --git a/crates/dash_vm/src/value/mod.rs b/crates/dash_vm/src/value/mod.rs
index ab732490..555aed2a 100755
--- a/crates/dash_vm/src/value/mod.rs
+++ b/crates/dash_vm/src/value/mod.rs
@@ -240,8 +240,12 @@ unsafe impl Trace for Value {
         match self {
             Value::Object(o) => o.trace(cx),
             Value::External(e) => e.trace(cx),
-            Value::String(_) => todo!(),
-            _ => {}
+            Value::String(s) => s.trace(cx),
+            Value::Number(_) => {}
+            Value::Boolean(_) => {}
+            Value::Undefined(_) => {}
+            Value::Null(_) => {}
+            Value::Symbol(s) => s.trace(cx),
         }
     }
 }
diff --git a/crates/dash_vm/src/value/object.rs b/crates/dash_vm/src/value/object.rs
index 8cbe9280..e16e9b96 100755
--- a/crates/dash_vm/src/value/object.rs
+++ b/crates/dash_vm/src/value/object.rs
@@ -219,6 +219,15 @@ pub enum PropertyKey {
     Symbol(Symbol),
 }
 
+unsafe impl Trace for PropertyKey {
+    fn trace(&self, cx: &mut TraceCtxt<'_>) {
+        match self {
+            PropertyKey::String(s) => s.trace(cx),
+            PropertyKey::Symbol(s) => s.trace(cx),
+        }
+    }
+}
+
 bitflags! {
     pub struct PropertyDataDescriptor: u8 {
         const CONFIGURABLE = 1 << 0;
@@ -526,20 +535,14 @@ impl NamedObject {
 
 unsafe impl Trace for NamedObject {
     fn trace(&self, cx: &mut TraceCtxt<'_>) {
-        let values = self.values.borrow();
-        for value in values.values() {
-            value.trace(cx);
-        }
-
-        let prototype = self.prototype.borrow();
-        if let Some(prototype) = &*prototype {
-            prototype.trace(cx);
-        }
-
-        let constructor = self.constructor.borrow();
-        if let Some(constructor) = &*constructor {
-            constructor.trace(cx);
-        }
+        let Self {
+            prototype,
+            constructor,
+            values,
+        } = self;
+        values.trace(cx);
+        prototype.trace(cx);
+        constructor.trace(cx);
     }
 }
 
diff --git a/crates/dash_vm/src/value/primitive.rs b/crates/dash_vm/src/value/primitive.rs
index 24950c67..232c45a0 100644
--- a/crates/dash_vm/src/value/primitive.rs
+++ b/crates/dash_vm/src/value/primitive.rs
@@ -3,6 +3,9 @@ use std::hash::{Hash, Hasher};
 use std::rc::Rc;
 use std::{fmt, iter};
 
+use dash_middle::interner;
+use dash_proc_macro::Trace;
+
 use crate::gc::handle::Handle;
 use crate::gc::interner::sym;
 use crate::gc::trace::{Trace, TraceCtxt};
@@ -362,18 +365,18 @@ impl Object for Null {
 // }
 
 // TODO: rename to JsSymbol
-#[derive(Debug, Clone, Hash, PartialEq, Eq)]
-pub struct Symbol(JsString);
+#[derive(Debug, Clone, Hash, PartialEq, Eq, Trace)]
+pub struct Symbol {
+    description: JsString,
+}
 
 impl Symbol {
-    pub fn new(description: JsString) -> Self {
-        Symbol(description)
+    pub fn sym(&self) -> interner::Symbol {
+        self.description.sym()
     }
-}
 
-unsafe impl Trace for Symbol {
-    fn trace(&self, cx: &mut TraceCtxt<'_>) {
-        todo!()
+    pub fn new(description: JsString) -> Self {
+        Symbol { description }
     }
 }
 
diff --git a/crates/dash_vm/src/value/regex.rs b/crates/dash_vm/src/value/regex.rs
index fb16fece..fb94329a 100644
--- a/crates/dash_vm/src/value/regex.rs
+++ b/crates/dash_vm/src/value/regex.rs
@@ -3,6 +3,7 @@ use std::cell::Cell;
 use dash_proc_macro::Trace;
 use dash_regex::{Flags, ParsedRegex};
 
+use crate::gc::trace::{Trace, TraceCtxt};
 use crate::{delegate, Vm};
 
 use super::object::{NamedObject, Object};
@@ -16,6 +17,18 @@ pub struct RegExpInner {
     pub last_index: Cell<usize>,
 }
 
+unsafe impl Trace for RegExpInner {
+    fn trace(&self, cx: &mut TraceCtxt<'_>) {
+        let Self {
+            regex: _,
+            flags: _,
+            source,
+            last_index: _,
+        } = self;
+        source.trace(cx);
+    }
+}
+
 #[derive(Debug, Trace)]
 pub struct RegExp {
     inner: Option<RegExpInner>,
diff --git a/crates/dash_wasm/src/externalfunction.rs b/crates/dash_wasm/src/externalfunction.rs
index abe6e4f5..97d926b4 100644
--- a/crates/dash_wasm/src/externalfunction.rs
+++ b/crates/dash_wasm/src/externalfunction.rs
@@ -1,5 +1,5 @@
 use dash_vm::gc::handle::Handle;
-use dash_vm::gc::trace::Trace;
+use dash_vm::gc::trace::{Trace, TraceCtxt};
 use dash_vm::localscope::LocalScope;
 use dash_vm::value::object::{NamedObject, Object, PropertyKey, PropertyValue};
 use dash_vm::value::{Typeof, Unrooted, Value};
@@ -16,8 +16,8 @@ impl ExternalFunction {
 }
 
 unsafe impl Trace for ExternalFunction {
-    fn trace(&self) {
-        self.1.trace();
+    fn trace(&self, cx: &mut TraceCtxt<'_>) {
+        self.1.trace(cx);
     }
 }
 
diff --git a/testrunner/.cargo/config.toml b/testrunner/.cargo/config.toml
new file mode 100644
index 00000000..6cbd5f2d
--- /dev/null
+++ b/testrunner/.cargo/config.toml
@@ -0,0 +1,4 @@
+
+[profile.dev]
+# override cranelift because the testrunner WILL require unwinding support
+codegen-backend = "llvm"