Reset global type state between tests (#4468)

Add a `destroyAllTypes` function to clear the global state of the type system
and use it in a custom gtest test fixture to ensure that each test starts and
ends with a fresh state.

2 files changed, 18 insertions, 0 deletions

diff --git a/src/wasm-type.h b/src/wasm-type.h
index 7d6306ef7..48b6f2217 100644
--- a/src/wasm-type.h
+++ b/src/wasm-type.h
@@ -45,6 +45,11 @@ void setTypeSystem(TypeSystem system);
 
 TypeSystem getTypeSystem();
 
+// Dangerous! Frees all types and heap types that have ever been created and
+// resets the type system's internal state. This is only really meant to be used
+// for tests.
+void destroyAllTypesForTestingPurposesOnly();
+
 // The types defined in this file. All of them are small and typically passed by
 // value except for `Tuple` and `Struct`, which may own an unbounded amount of
 // data.
diff --git a/src/wasm/wasm-type.cpp b/src/wasm/wasm-type.cpp
index fc42fe230..af382da23 100644
--- a/src/wasm/wasm-type.cpp
+++ b/src/wasm/wasm-type.cpp
@@ -653,6 +653,11 @@ template<typename Info> struct Store {
   }
   bool hasCanonical(const Info& info, typename Info::type_t& canonical);
 
+  void clear() {
+    typeIDs.clear();
+    constructedTypes.clear();
+  }
+
 private:
   template<typename Ref> typename Info::type_t doInsert(Ref& infoRef) {
     const Info& info = [&]() {
@@ -754,12 +759,20 @@ struct SignatureTypeCache {
     std::lock_guard<std::mutex> lock(mutex);
     cache.insert({type.getSignature(), type});
   }
+
+  void clear() { cache.clear(); }
 };
 
 static SignatureTypeCache nominalSignatureCache;
 
 } // anonymous namespace
 
+void destroyAllTypesForTestingPurposesOnly() {
+  globalTypeStore.clear();
+  globalHeapTypeStore.clear();
+  nominalSignatureCache.clear();
+}
+
 Type::Type(std::initializer_list<Type> types) : Type(Tuple(types)) {}
 
 Type::Type(const Tuple& tuple) {