1 files changed, 72 insertions, 0 deletions
diff --git a/compiler/enco/core/src/Transforms/DeadBagElimination.cpp b/compiler/enco/core/src/Transforms/DeadBagElimination.cpp
new file mode 100644
index 000000000..b3c598a55
--- /dev/null
+++ b/compiler/enco/core/src/Transforms/DeadBagElimination.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2018 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * 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 "DeadBagElimination.h"
+
+#include <set>
+
+namespace
+{
+
+/// @brief Return true if a given bag is marked as either input or output
+bool is_public(const coco::Bag *b) { return b->isInput() || b->isOutput(); }
+
+/// @brief Return the set of "dead" bags in a given module
+std::set<coco::Bag *> dead_bags(const coco::Module *m)
+{
+  std::set<coco::Bag *> res;
+
+  for (uint32_t n = 0; n < m->entity()->bag()->size(); ++n)
+  {
+    auto bag = m->entity()->bag()->at(n);
+
+    if (coco::readers(bag).empty() && !is_public(bag))
+    {
+      res.insert(bag);
+    }
+  }
+
+  return res;
+}
+
+} // namespace
+
+namespace enco
+{
+
+void eliminate_dead_bag(enco::Code *code)
+{
+  auto m = code->module();
+
+  // Destroy a dead bag and its updaters
+  for (auto bag : dead_bags(m))
+  {
+    for (auto updater : coco::updaters(bag))
+    {
+      auto ins = updater->loc();
+
+      assert(ins != nullptr);
+
+      ins->detach();
+      m->entity()->instr()->destroy(ins);
+    }
+
+    bag->replaceWith(nullptr);
+    m->entity()->bag()->destroy(bag);
+  }
+}
+
+} // namespace enco