1 files changed, 54 insertions, 0 deletions
diff --git a/src/passes/ReorderLocals.cpp b/src/passes/ReorderLocals.cpp
new file mode 100644
index 000000000..1b5e998c4
--- /dev/null
+++ b/src/passes/ReorderLocals.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2016 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.
+ */
+
+//
+// Sorts locals by access frequency.
+//
+
+
+#include <memory>
+
+#include <wasm.h>
+#include <pass.h>
+
+namespace wasm {
+
+struct ReorderLocals : public WalkerPass<WasmWalker<ReorderLocals, void>> {
+
+  std::map<Name, uint32_t> counts;
+
+  void visitFunction(Function *curr) {
+    sort(curr->locals.begin(), curr->locals.end(), [this](NameType a, NameType b) -> bool {
+      if (this->counts[a.name] == this->counts[b.name]) {
+        return strcmp(a.name.str, b.name.str) > 0;
+      }
+      return this->counts[a.name] > this->counts[b.name];
+    });
+    counts.clear();
+  }
+
+  void visitGetLocal(GetLocal *curr) {
+    counts[curr->name]++;
+  }
+
+  void visitSetLocal(SetLocal *curr) {
+    counts[curr->name]++;
+  }
+};
+
+static RegisterPass<ReorderLocals> registerPass("reorder-locals", "sorts locals by access frequency");
+
+} // namespace wasm