[Wasm GC] rtt.fresh_sub (#3936)

This is the same as rtt.sub, but creates a "new" rtt each time. See

https://docs.google.com/document/d/1DklC3qVuOdLHSXB5UXghM_syCh-4cMinQ50ICiXnK3Q/edit#

The old Literal implementation of rtts becomes a little more complex here,
as it was designed for the original spec where only structure matters. It may
be worth a complete redesign there, but for now as the spec is in flux I think
the approach here is good enough.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index a193dd8d5..79f3ec8df 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -795,6 +795,11 @@ public:
     ret->finalize();
     return ret;
   }
+  RttSub* makeRttFreshSub(HeapType heapType, Expression* parent) {
+    auto* ret = makeRttSub(heapType, parent);
+    ret->fresh = true;
+    return ret;
+  }
   template<typename T>
   StructNew* makeStructNew(Expression* rtt, const T& args) {
     auto* ret = wasm.allocator.alloc<StructNew>();