Enhance the support for reshape

Author: daquexian

tools/onnx2bnn/OnnxConverter.cpp

@@ -262,14 +262,12 @@ std::vector<std::string> OnnxConverter::Convert(
     for (const auto &node : model_proto_.graph().node()) {
         NodeAttrHelper helper(node);
         const auto &op = node.op_type();
-        if (has_reshape && op != "Gemm") {
-            throw std::invalid_argument(
-                "Reshape can only be the last layer or precede a gemm layer "
-                "for now");
-        }
-        has_reshape = false;
         VLOG(5) << "Node " << node.name();
         if (op == "Conv") {
+            if (has_reshape) {
+                throw std::invalid_argument("Reshape before " + op +
+                                            " is not supported");
+            }
             VLOG(5) << "Start converting Conv";
             auto strides = helper.get("strides", vector<int>{1, 1});
             auto pads = helper.get("pads", vector<int>{0, 0, 0, 0});
@@ -319,6 +317,10 @@ std::vector<std::string> OnnxConverter::Convert(
             VLOG(5) << "Converting Conv completed";
         } else if (op == "AveragePool" || op == "MaxPool" ||
                    op == "GlobalAveragePool" || op == "GlobalMaxPool") {
+            if (has_reshape) {
+                throw std::invalid_argument("Reshape before " + op +
+                                            " is not supported");
+            }
             VLOG(5) << "Start converting Pool";
             auto input_name = m(node.input(0));
             auto output_name = m(node.output(0));
@@ -407,6 +409,10 @@ std::vector<std::string> OnnxConverter::Convert(
             layers_.push_back(layer);
             VLOG(5) << "Converting Relu completed";
         } else if (op == "Add") {
+            if (has_reshape) {
+                throw std::invalid_argument("Reshape before " + op +
+                                            " is not supported");
+            }
             VLOG(5) << "Start converting Add";
             auto input1_name = m(node.input(0));
             auto input2_name = m(node.input(1));
@@ -420,6 +426,9 @@ std::vector<std::string> OnnxConverter::Convert(
             layers_.push_back(layer);
             VLOG(5) << "Converting Add completed";
         } else if (op == "Gemm") {
+            if (has_reshape) {
+                has_reshape = false;
+            }
             VLOG(5) << "Start converting Gemm";
             auto transA = helper.get("transA", 0);
             auto transB = helper.get("transB", 0);
@@ -478,6 +487,10 @@ std::vector<std::string> OnnxConverter::Convert(
             layers_.push_back(layer);
             VLOG(5) << "Converting Softmax completed";
         } else if (op == "Concat") {
+            if (has_reshape) {
+                throw std::invalid_argument("Reshape before " + op +
+                                            " is not supported");
+            }
             VLOG(5) << "Start converting Concat";
             vector<std::string> concat_inputs_str;
             for (const auto &onnx_input : node.input()) {