Preserve Function HeapTypes (#3952)

When using nominal types, func.ref of two functions with identical signatures
but different HeapTypes will yield different types. To preserve these semantics,
Functions need to track their HeapTypes, not just their Signatures.

This PR replaces the Signature field in Function with a HeapType field and adds
new utility methods to make it almost as simple to update and query the function
HeapType as it was to update and query the Function Signature.

1 files changed, 6 insertions, 6 deletions

diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index 54c82159f..5b1163ae0 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -1087,14 +1087,14 @@ void RefAs::finalize() {
   }
 }
 
-size_t Function::getNumParams() { return sig.params.size(); }
+size_t Function::getNumParams() { return getParams().size(); }
 
 size_t Function::getNumVars() { return vars.size(); }
 
-size_t Function::getNumLocals() { return sig.params.size() + vars.size(); }
+size_t Function::getNumLocals() { return getParams().size() + vars.size(); }
 
 bool Function::isParam(Index index) {
-  size_t size = sig.params.size();
+  size_t size = getParams().size();
   assert(index < size + vars.size());
   return index < size;
 }
@@ -1141,12 +1141,12 @@ Index Function::getLocalIndex(Name name) {
   return iter->second;
 }
 
-Index Function::getVarIndexBase() { return sig.params.size(); }
+Index Function::getVarIndexBase() { return getParams().size(); }
 
 Type Function::getLocalType(Index index) {
-  auto numParams = sig.params.size();
+  auto numParams = getParams().size();
   if (index < numParams) {
-    return sig.params[index];
+    return getParams()[index];
   } else if (isVar(index)) {
     return vars[index - numParams];
   } else {