2 files changed, 55 insertions, 0 deletions
diff --git a/src/ir/names.h b/src/ir/names.h
new file mode 100644
index 000000000..a589571bf
--- /dev/null
+++ b/src/ir/names.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2017 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.
+ */
+
+#ifndef wasm_ir_names_h
+#define wasm_ir_names_h
+
+#include "wasm.h"
+
+namespace wasm {
+
+namespace Names {
+
+// Add explicit names for function locals not yet named, and do not
+// modify existing names
+inline void ensureNames(Function* func) {
+  std::unordered_set<Name> seen;
+  for (auto& pair : func->localNames) {
+    seen.insert(pair.second);
+  }
+  Index nameIndex = seen.size();
+  for (Index i = 0; i < func->getNumLocals(); i++) {
+    if (!func->hasLocalName(i)) {
+      while (1) {
+        auto name = Name::fromInt(nameIndex++);
+        if (seen.count(name) == 0) {
+          func->localNames[i] = name;
+          func->localIndices[name] = i;
+          seen.insert(name);
+          break;
+        }
+      }
+    }
+  }
+}
+
+} // namespace Names
+
+} // namespace wasm
+
+#endif // wasm_ir_names_h
diff --git a/src/passes/I64ToI32Lowering.cpp b/src/passes/I64ToI32Lowering.cpp
index 0b476bb15..a9ac2da82 100644
--- a/src/passes/I64ToI32Lowering.cpp
+++ b/src/passes/I64ToI32Lowering.cpp
@@ -27,6 +27,7 @@
 #include "emscripten-optimizer/istring.h"
 #include "support/name.h"
 #include "wasm-builder.h"
+#include "ir/names.h"
 
 
 namespace wasm {
@@ -140,6 +141,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     func->localNames.clear();
     func->localIndices.clear();
     Index newIdx = 0;
+    Names::ensureNames(&oldFunc);
     for (Index i = 0; i < oldFunc.getNumLocals(); ++i) {
       assert(oldFunc.hasLocalName(i));
       Name lowName = oldFunc.getLocalName(i);