[Types] Refactor signature collection to heap type collection. NFC. (#3420)

This will allow writing GC types in the future, which are non-signature
heap types.

To allow this PR to work, it adds operator< for HeapType so that it
can be used in the data structures that collect uses.

Drive-by fix of a weird hack with sending a Name* in Print.

1 files changed, 32 insertions, 10 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index c597028be..ba3981e21 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -141,6 +141,11 @@ struct TypeName {
   TypeName(Type type) : type(type) {}
 };
 
+struct HeapTypeName {
+  HeapType type;
+  HeapTypeName(HeapType type) : type(type) {}
+};
+
 std::ostream& operator<<(std::ostream& os, TypeName typeName) {
   auto type = typeName.type;
   if (type.isRef() && !type.isBasic()) {
@@ -160,6 +165,16 @@ std::ostream& operator<<(std::ostream& os, TypeName typeName) {
   return os << SExprType(typeName.type);
 }
 
+std::ostream& operator<<(std::ostream& os, HeapTypeName typeName) {
+  auto type = typeName.type;
+  if (type.isSignature()) {
+    os << SigName(type.getSignature());
+  } else {
+    os << type;
+  }
+  return os;
+}
+
 } // anonymous namespace
 
 // Printing "unreachable" as a instruction prefix type is not valid in wasm text
@@ -2348,10 +2363,10 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     WASM_UNREACHABLE("TODO (gc): array.len");
   }
   // Module-level visitors
-  void handleSignature(Signature curr, Name* funcName = nullptr) {
+  void handleSignature(Signature curr, Name name = Name()) {
     o << "(func";
-    if (funcName) {
-      o << " $" << *funcName;
+    if (name.is()) {
+      o << " $" << name;
     }
     if (curr.params.size() > 0) {
       o << maybeSpace;
@@ -2375,6 +2390,13 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     }
     o << ")";
   }
+  void handleHeapType(HeapType type) {
+    if (type.isSignature()) {
+      handleSignature(type.getSignature());
+    } else {
+      WASM_UNREACHABLE("unsupported heap type");
+    }
+  }
   void visitExport(Export* curr) {
     o << '(';
     printMedium(o, "export ");
@@ -2453,7 +2475,7 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     lastPrintedLocation = {0, 0, 0};
     o << '(';
     emitImportHeader(curr);
-    handleSignature(curr->sig, &curr->name);
+    handleSignature(curr->sig, curr->name);
     o << ')';
     o << maybeNewLine;
   }
@@ -2702,15 +2724,15 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
       printName(curr->name, o);
     }
     incIndent();
-    std::vector<Signature> signatures;
-    std::unordered_map<Signature, Index> indices;
-    ModuleUtils::collectSignatures(*curr, signatures, indices);
-    for (auto sig : signatures) {
+    std::vector<HeapType> types;
+    std::unordered_map<HeapType, Index> indices;
+    ModuleUtils::collectHeapTypes(*curr, types, indices);
+    for (auto type : types) {
       doIndent(o, indent);
       o << '(';
       printMedium(o, "type") << ' ';
-      o << SigName(sig) << ' ';
-      handleSignature(sig);
+      o << HeapTypeName(type) << ' ';
+      handleHeapType(type);
       o << ")" << maybeNewLine;
     }
     ModuleUtils::iterImportedMemories(