Ensure a deterministic order in the type names section (#5590)

Before this PR we iterated over an unordered set. Replace that with an
iteration on a vector. (Also, the value in the set was not even used, so
this should even be faster.)

Add random names in the fuzzer to types, the lack of which is I believe
the reason this was not detected before.

2 files changed, 6 insertions, 1 deletions

diff --git a/src/tools/fuzzing/fuzzing.cpp b/src/tools/fuzzing/fuzzing.cpp
index 73aff5acb..45cfbde0f 100644
--- a/src/tools/fuzzing/fuzzing.cpp
+++ b/src/tools/fuzzing/fuzzing.cpp
@@ -263,6 +263,11 @@ void TranslateToFuzzReader::setupHeapTypes() {
       // non-nullable bottom heap type).
       if (!type.isBottom() && !type.isBasic()) {
         interestingHeapTypes.push_back(type);
+        if (oneIn(2)) {
+          // Add a name for this type.
+          wasm.typeNames[type].name =
+            "generated_type$" + std::to_string(interestingHeapTypes.size());
+        }
       }
     }
   }
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index 5326972b0..89ad82abf 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -896,7 +896,7 @@ void WasmBinaryWriter::writeNames() {
   // type names
   {
     std::vector<HeapType> namedTypes;
-    for (auto& [type, _] : indexedTypes.indices) {
+    for (auto type : indexedTypes.types) {
       if (wasm->typeNames.count(type) && wasm->typeNames[type].name.is()) {
         namedTypes.push_back(type);
       }