[PASS] Layout transform pass (#233)

* [PASS] Layout transform pass

* Fix according to comment

* Fix

apps/graph_executor/src/graph_pass.cc

@@ -387,5 +387,115 @@ NNVM_REGISTER_OP(tvm_op)
     const TVMOpParam& param = nnvm::get<TVMOpParam>(attrs.parsed);
     return param.num_outputs;
   });
+
+
+inline bool IsPair(LayoutInfo in, LayoutInfo out) {
+  if (in.src == out.dst && in.dst == out.src) return true;
+  return false;
+}
+
+inline LayoutInfo GetLayout(const nnvm::OpMap<FTVMLayoutInfo>& layouts,
+                            const nnvm::NodePtr& n, int idx) {
+  return layouts[n->op()](n->attrs)[idx];
+}
+
+nnvm::NodePtr CreateLayoutTransformNode(std::string src, std::string dst) {
+  static const nnvm::Op* trans_op = nnvm::Op::Get("layout_transform");
+  static int count = 0;
+  nnvm::NodePtr n = nnvm::Node::Create();
+  n->attrs.op = trans_op;
+  n->attrs.name = src + "_to_" + dst + std::to_string(count++);
+  n->attrs.dict["src"] = src;
+  n->attrs.dict["dst"] = dst;
+  return n;
+}
+
+
+/*!
+ * \brief A simple layout transform pass that will
+ *  insert layout transform nodes automatically.
+ */
+nnvm::Graph LayoutTransform(nnvm::Graph src) {
+  static auto& ilayouts =
+    nnvm::Op::GetAttr<FTVMInputsLayoutInfo>("FTVMInputsLayoutInfo");
+  static auto& olayouts =
+    nnvm::Op::GetAttr<FTVMOutputsLayoutInfo>("FTVMOutputsLayoutInfo");
+
+  std::unordered_map<nnvm::Node*, nnvm::NodePtr> mirror_map;
+  std::unordered_map<nnvm::Node*, std::vector<nnvm::NodePtr> > transformed;
+
+  DFSVisit(src.outputs, [&](const nnvm::NodePtr& n) {
+      nnvm::NodePtr new_node = nnvm::Node::Create();
+      *new_node = *n;
+      if (new_node->is_variable()) {
+        mirror_map[n.get()] = new_node;
+        return;
+      }
+
+      if (olayouts.count(n->op())) {
+        std::vector<nnvm::NodePtr> tnodes(n->num_outputs(), nullptr);
+        for (uint32_t i = 0; i < n->num_outputs(); ++i) {
+          LayoutInfo layout = GetLayout(olayouts, n, i);
+          tnodes[i] = CreateLayoutTransformNode(layout.src, layout.dst);
+          tnodes[i]->inputs.emplace_back(nnvm::NodeEntry{new_node, i, 0});
+        }
+        transformed.emplace(n.get(), std::move(tnodes));
+      }
+
+      for (size_t idx = 0; idx < n->inputs.size(); ++idx) {
+        const nnvm::NodeEntry& e = n->inputs[idx];
+        const nnvm::NodePtr& in = e.node;
+        new_node->inputs[idx] =
+          nnvm::NodeEntry{mirror_map.at(in.get()), e.index, e.version};
+
+        bool otrans = olayouts.count(in->op());
+        bool itrans = ilayouts.count(n->op());
+        if (otrans && itrans) {
+          LayoutInfo olayout = GetLayout(olayouts, in, e.index);
+          LayoutInfo ilayout = GetLayout(ilayouts, n, idx);
+          if (IsPair(olayout, ilayout)) {
+            continue;
+          }
+        }
+
+        if (otrans) {
+          const auto& tnodes = transformed.at(in.get());
+          new_node->inputs[idx] =
+            nnvm::NodeEntry{tnodes[e.index], 0, 0};
+        }
+
+        if (itrans) {
+          LayoutInfo layout = GetLayout(ilayouts, n, idx);
+          nnvm::NodePtr tnode =
+            CreateLayoutTransformNode(layout.src, layout.dst);
+          tnode->inputs.emplace_back(new_node->inputs[idx]);
+          new_node->inputs[idx] = nnvm::NodeEntry{tnode, 0, 0};
+        }
+      }
+      mirror_map[n.get()] = std::move(new_node);
+    });
+
+  std::vector<nnvm::NodeEntry> outputs;
+  for (const auto& e : src.outputs) {
+    if (olayouts.count(e.node->op())) {
+      const auto& tnodes = transformed.at(e.node.get());
+      outputs.emplace_back(nnvm::NodeEntry{tnodes[e.index], 0, 0});
+    } else {
+      outputs.emplace_back(
+        nnvm::NodeEntry{mirror_map.at(e.node.get()), e.index, e.version});
+    }
+  }
+
+  nnvm::Graph ret;
+  ret.outputs = std::move(outputs);
+  return ret;
+}
+
+NNVM_REGISTER_PASS(LayoutTransform)
+.set_body(LayoutTransform);
+
+NNVM_REGISTER_OP(layout_transform)
+.set_num_inputs(1)
+.set_num_outputs(1);
 }  // namespace contrib
 }  // namespace tvm

apps/graph_executor/src/op_attr_types.h

@@ -52,6 +52,36 @@ using FTVMSchedule = std::function<
            const Array<Tensor>& outs,
            const std::string& target)>;
 
+/*!
+ * \brief Layout transform information,
+ *  from source layout to destination layout.
+ */
+struct LayoutInfo {
+  using Layout = std::string;
+  Layout src;
+  Layout dst;
+};
+
+/*!
+ * \brief Layout info of the node.
+ * \param attrs The attribute of the node.
+ * \return layouts A vector of inputs/outputs layout info.
+ */
+using FTVMLayoutInfo = std::function<
+  std::vector<LayoutInfo>(const NodeAttrs& attrs)>;
+/*!
+ * \brief Inputs layout info of the node.
+ * \param attrs The attribute of the node.
+ * \return layouts A vector of inputs layout info.
+ */
+using FTVMInputsLayoutInfo  = FTVMLayoutInfo;
+/*!
+ * \brief Outputs layout info of the node.
+ * \param attrs The attribute of the node.
+ * \return layouts A vector of outputs layout info.
+ */
+using FTVMOutputsLayoutInfo = FTVMLayoutInfo;
+
 // The storage result of op
 enum OpPatternKind : int {
   // Elementwise operation