when creating blocks in binary format parsing, we know if a block has a break to it - use that to avoid rescanning blocks for unreachability purposes (#1495)

1 files changed, 10 insertions, 3 deletions

diff --git a/src/wasm.h b/src/wasm.h
index f5802052b..9d8648308 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -250,13 +250,20 @@ public:
   Name name;
   ExpressionList list;
 
+  // set the type purely based on its contents. this scans the block, so it is not fast.
+  void finalize();
+
   // set the type given you know its type, which is the case when parsing
   // s-expression or binary, as explicit types are given. the only additional work
-  // this does is to set the type to unreachable in the cases that is needed.
+  // this does is to set the type to unreachable in the cases that is needed
+  // (which may require scanning the block)
   void finalize(Type type_);
 
-  // set the type purely based on its contents. this scans the block, so it is not fast
-  void finalize();
+  // set the type given you know its type, and you know if there is a break to this
+  // block. this avoids the need to scan the contents of the block in the case that
+  // it might be unreachable, so it is recommended if you already know the type
+  // and breakability anyhow.
+  void finalize(Type type_, bool hasBreak);
 };
 
 class If : public SpecificExpression<Expression::IfId> {