Add br_on_exn instruction (#1016)

It takes two u32 immediates: the branch depth and an exception index. The
stack signature is `[expect_ref] -> [except_ref]`, so the `except_ref`
can be tested easily against multiple exception types.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/resolve-names.cc b/src/resolve-names.cc
index 3ebd3567..f963a0fc 100644
--- a/src/resolve-names.cc
+++ b/src/resolve-names.cc
@@ -40,6 +40,7 @@ class NameResolver : public ExprVisitor::DelegateNop {
   Result EndBlockExpr(BlockExpr*) override;
   Result OnBrExpr(BrExpr*) override;
   Result OnBrIfExpr(BrIfExpr*) override;
+  Result OnBrOnExnExpr(BrOnExnExpr*) override;
   Result OnBrTableExpr(BrTableExpr*) override;
   Result OnCallExpr(CallExpr*) override;
   Result OnCallIndirectExpr(CallIndirectExpr*) override;
@@ -257,6 +258,12 @@ Result NameResolver::OnBrIfExpr(BrIfExpr* expr) {
   return Result::Ok;
 }
 
+Result NameResolver::OnBrOnExnExpr(BrOnExnExpr* expr) {
+  ResolveLabelVar(&expr->label_var);
+  ResolveEventVar(&expr->event_var);
+  return Result::Ok;
+}
+
 Result NameResolver::OnBrTableExpr(BrTableExpr* expr) {
   for (Var& target : expr->targets)
     ResolveLabelVar(&target);