feat(opr): add mutable tensor opr

GitOrigin-RevId: 7f8a3d7b661c18fb407047a78b965630b52e61d9

imperative/src/impl/opr_utility.cpp

@@ -271,6 +271,69 @@ void NopCallback::do_execute(ExecEnv& env) {
     env.dispatch_on_comp_node(cn, runner);
 }
 
+MGB_DYN_TYPE_OBJ_FINAL_IMPL(MutableTensor);
+MutableTensor::MutableTensor(
+        cg::ComputingGraph& graph, std::shared_ptr<DeviceTensorND> dev_tensor,
+        std::shared_ptr<HostTensorND> host_tensor, const OperatorNodeConfig& config)
+        : Super(&graph, config, {}, {}) {
+    m_dev_tensor = dev_tensor;
+    m_host_tensor = host_tensor;
+
+    add_output(None)
+            ->add_flag(VarNode::Flag::ALLOW_EMPTY_SHAPE)
+            .add_flag(VarNode::Flag::NO_SYS_MEM_ALLOC)
+            .dtype(m_dev_tensor->dtype());
+    add_equivalence_component<ScalarHash<const void*>>(this);
+}
+
+SymbolVar MutableTensor::make(
+        cg::ComputingGraph& graph, std::shared_ptr<DeviceTensorND> dev_tensor,
+        std::shared_ptr<HostTensorND> host_tensor, const OperatorNodeConfig& config) {
+    return graph
+            .insert_opr(std::make_unique<MutableTensor>(
+                    graph, dev_tensor, host_tensor, config))
+            ->output(0);
+}
+
+void MutableTensor::init_output_comp_node() {
+    if (config().has_comp_node_set()) {
+        mgb_assert(
+                config().get_single_comp_node() == m_dev_tensor->comp_node(),
+                "comp_node mismatch");
+    }
+    comp_node(m_dev_tensor->comp_node());
+}
+
+cg::OperatorNodeBase::NodeProp* MutableTensor::do_make_node_prop() const {
+    auto ret = Super::do_make_node_prop();
+    ret->add_flag(NodeProp::Flag::IMPURE_OUTPUT_MEM_PLAN);
+    return ret;
+}
+
+void MutableTensor::scn_do_execute() {
+    output(0)->reset_dev_tensor_from_tensor(*m_dev_tensor);
+}
+
+void MutableTensor::init_output_static_infer_desc() {
+    using namespace cg::static_infer;
+    auto& mgr = owner_graph()->static_infer_manager();
+    auto infer_shape = [this](TensorShape& dest, const InpVal&) {
+        dest = m_dev_tensor->shape();
+        return true;
+    };
+    mgr.register_shape_infer(output(0), {SourceType::MUTABLE, {}, infer_shape});
+    if (m_host_tensor) {
+        auto infer_value = [this](DeviceTensorND& dest, const InpVal&) {
+            if (!m_host_tensor->layout().ndim) {
+                return false;
+            }
+            dest = m_host_tensor->proxy_to_default_cpu();
+            return true;
+        };
+        mgr.register_value_infer(output(0), {SourceType::MUTABLE, {}, infer_value});
+    }
+}
+
 }  // namespace opr
 }  // namespace mgb
 

imperative/src/include/megbrain/imperative/opr_utility.h

@@ -16,6 +16,7 @@
 #include "megbrain/opr/internal/identical_fwd.h"
 #include "megbrain/opr/internal/megdnn_opr_wrapper.h"
 #include "megbrain/opr/internal/param_tag_defs.h"
+#include "megbrain/opr/io.h"
 #include "megbrain/opr/param_defs.h"
 #include "megbrain/serialization/sereg.h"
 
@@ -106,6 +107,28 @@ protected:
 private:
     callback_t m_callback;
 };
+
+MGB_DEFINE_OPR_CLASS(MutableTensor, cg::SingleCNOperatorNodeBase) // {
+public:
+    MutableTensor(
+            cg::ComputingGraph& graph, std::shared_ptr<DeviceTensorND> dev_tensor,
+            std::shared_ptr<HostTensorND> host_tensor,
+            const OperatorNodeConfig& config);
+    static SymbolVar make(
+            cg::ComputingGraph& graph, std::shared_ptr<DeviceTensorND> dev_tensor,
+            std::shared_ptr<HostTensorND> host_tensor = {},
+            const OperatorNodeConfig& config = {});
+
+protected:
+    void init_output_comp_node() override;
+    void init_output_static_infer_desc() override;
+    cg::OperatorNodeBase::NodeProp* do_make_node_prop() const override;
+    void scn_do_execute() override;
+
+private:
+    std::shared_ptr<DeviceTensorND> m_dev_tensor;
+    std::shared_ptr<HostTensorND> m_host_tensor;
+};
 }  // namespace opr
 }  // namespace mgb