Make IndexedTypeNameGenerator more powerful (#4511)

Allow IndexedTypeNameGenerator to be configured with a custom prefix and also
allow it to be parameterized with an explicit fallback generator. This allows
multiple IndexedTypeNameGenerators to be composed together, for example.

2 files changed, 15 insertions, 5 deletions

diff --git a/src/tools/wasm-fuzz-types.cpp b/src/tools/wasm-fuzz-types.cpp
index 4fba27753..d2540636f 100644
--- a/src/tools/wasm-fuzz-types.cpp
+++ b/src/tools/wasm-fuzz-types.cpp
@@ -95,8 +95,8 @@ void Fuzzer::printTypes() {
     TypeNames getNames(HeapType type) {
       Fatal() << "trying to print unknown heap type";
     }
-  };
-  IndexedTypeNameGenerator<FatalTypeNameGenerator> print(types);
+  } fatalGenerator;
+  IndexedTypeNameGenerator<FatalTypeNameGenerator> print(types, fatalGenerator);
   std::unordered_map<HeapType, size_t> seen;
   std::optional<RecGroup> currRecGroup;
   auto inRecGroup = [&]() { return currRecGroup && currRecGroup->size() > 1; };
diff --git a/src/wasm-type-printing.h b/src/wasm-type-printing.h
index fcf05db17..685d488fd 100644
--- a/src/wasm-type-printing.h
+++ b/src/wasm-type-printing.h
@@ -67,13 +67,23 @@ struct DefaultTypeNameGenerator
 template<typename FallbackGenerator = DefaultTypeNameGenerator>
 struct IndexedTypeNameGenerator
   : TypeNameGeneratorBase<IndexedTypeNameGenerator<FallbackGenerator>> {
-  FallbackGenerator fallback;
+  DefaultTypeNameGenerator defaultGenerator;
+  FallbackGenerator& fallback;
   std::unordered_map<HeapType, TypeNames> names;
-  template<typename T> IndexedTypeNameGenerator(T& types) {
+
+  template<typename T>
+  IndexedTypeNameGenerator(T& types,
+                           FallbackGenerator& fallback,
+                           const std::string& prefix = "")
+    : fallback(fallback) {
     for (size_t i = 0; i < types.size(); ++i) {
-      names.insert({types[i], {std::to_string(i), {}}});
+      names.insert({types[i], {prefix + std::to_string(i), {}}});
     }
   }
+  template<typename T>
+  IndexedTypeNameGenerator(T& types, const std::string& prefix = "")
+    : IndexedTypeNameGenerator(types, defaultGenerator, prefix) {}
+
   TypeNames getNames(HeapType type) {
     if (auto it = names.find(type); it != names.end()) {
       return it->second;