[Wasm GC] Add a Name-Types pass (#3735)

The pass gives a simple short name to each type, $type$N. This can be
useful in debugging, to avoid the autogenerated names which can be very
long.

4 files changed, 52 insertions, 0 deletions

diff --git a/src/passes/CMakeLists.txt b/src/passes/CMakeLists.txt
index e49afcde3..906871b91 100644
--- a/src/passes/CMakeLists.txt
+++ b/src/passes/CMakeLists.txt
@@ -45,6 +45,7 @@ set(passes_SOURCES
   Metrics.cpp
   MinifyImportsAndExports.cpp
   NameList.cpp
+  NameTypes.cpp
   NoExitRuntime.cpp
   OptimizeAddedConstants.cpp
   OptimizeInstructions.cpp
diff --git a/src/passes/NameTypes.cpp b/src/passes/NameTypes.cpp
new file mode 100644
index 000000000..2939f9ad5
--- /dev/null
+++ b/src/passes/NameTypes.cpp
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2021 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "ir/module-utils.h"
+#include "pass.h"
+#include "wasm.h"
+
+//
+// Ensures each type has a name. This can be useful for debugging.
+//
+// TODO: keep existing useful (short-enough) names, and just replace ones that
+//       are bothersome
+//
+
+using namespace std;
+
+namespace wasm {
+
+struct NameTypes : public Pass {
+  void run(PassRunner* runner, Module* module) override {
+    // Find all the types.
+    std::vector<HeapType> types;
+    std::unordered_map<HeapType, Index> typeIndices;
+    ModuleUtils::collectHeapTypes(*module, types, typeIndices);
+
+    // Ensure simple names.
+    size_t i = 0;
+    for (auto& type : types) {
+      module->typeNames[type].name = "type$" + std::to_string(i++);
+    }
+  }
+};
+
+Pass* createNameTypesPass() { return new NameTypes(); }
+
+} // namespace wasm
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index 6dd9926f6..72c415ed8 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -217,6 +217,7 @@ void PassRegistry::registerPasses() {
                "apply the assumption that asyncify never unwinds",
                createModAsyncifyNeverUnwindPass);
   registerPass("nm", "name list", createNameListPass);
+  registerPass("name-types", "(re)name all heap types", createNameTypesPass);
   registerPass("no-exit-runtime",
                "removes calls to atexit(), which is valid if the C runtime "
                "will never be exited",
diff --git a/src/passes/passes.h b/src/passes/passes.h
index c844ec485..93f986773 100644
--- a/src/passes/passes.h
+++ b/src/passes/passes.h
@@ -71,6 +71,7 @@ Pass* createMinifyImportsAndExportsPass();
 Pass* createMinifyImportsAndExportsAndModulesPass();
 Pass* createMetricsPass();
 Pass* createNameListPass();
+Pass* createNameTypesPass();
 Pass* createNoExitRuntimePass();
 Pass* createOptimizeAddedConstantsPass();
 Pass* createOptimizeAddedConstantsPropagatePass();