Class ov::AttributeVisitor¶
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class AttributeVisitor¶
Visits the attributes of a node, primarily for serialization-like tasks.
Attributes are the node parameters that are always compile-time constants. Values computed from the graph topology and attributes during compilation are not attributes.
Attributes have a wide variety of types, but serialization formats are more restricted. We assume serialization easily supports scalar types of bool 64-bit signed, string, and double, and has specialized ways to support numeric arrays and raw data+size. The visitor and adapter convert between the limited serialization types and the unlimited attribute types.
A visitor is passed to an op’s visit_attributes method. The visit_attributes method calls the template method visitor.on_attribute<AT>(const std::string& name, AT& value) on each attribute. The visitor can read or write the attribute’s value. The on_attribute method creates an AttributeAdapter<AT> for the value and passes it to one of the visitors on_adapter methods. The on_adapter methods expect a reference to a ValueAccessor<VAT> or a VisitorAdapter. A ValueAccessor<VAT> has get/set methods that can be used to read/write the attribute value as type VAT. These methods are triggered by deriving AttributeAdapter<AT> from ValueAccessor<VAT>. For more complex cases, such as structs, the on_adapter method for VisitorAdapter passes the name and visitor to the adapter, so that the adapter can perform additional work such as visiting struct members or sequence values.
When a node visits an attribute with structure, the node’s on_attribute passes a name for the entire attribute, but the struct will have its own methods to be visited. Similarly, a vector will have a sequence of members to be visited. The adapter may use the visitor methods start_struct/finish_struct and start_vector/next_vector/finish_vector to inidicate nexted members.
The visitor method get_name_with_context creates a generic nested version of the name. Visitors can override according to their serialization requirements.
Attributes that are shared_ptr<Node> are special. They must have been already been registered with the visitor using register_node, which needs a shared pointer to a node and a string ID. The ID string will be used to serialize the node or find the node during deserialization.
Subclassed by ov::frontend::FWVisitor, ov::frontend::FWVisitorInputAttributes
Public Functions
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virtual void on_adapter(const std::string &name, ValueAccessor<void> &adapter) = 0¶
handles all specialized on_adapter methods implemented by the visitor.
The adapter implements get_type_info(), which can be used to determine the adapter directly or via is_type and as_type on any platform
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virtual void on_adapter(const std::string &name, VisitorAdapter &adapter)¶
Hook for adapters that need visitor access.
Provides API to handle openvino Function attribute type, accessed as ValueAccessor.
- Parameters
name – attribute name
adapter – reference to a Function ValueAccessor<VAT>
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template<typename AT>
inline void on_attribute(const std::string &name, AT &value)¶ The generic visitor. There must be a definition of AttributeAdapter<T> that can convert to a ValueAccessor
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inline const std::vector<std::string> &get_context() const¶
- Returns
The nested context of visits
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virtual std::string get_name_with_context()¶
- Returns
context prepended to names
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virtual void start_structure(const std::string &name)¶
Start visiting a nested structure.
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virtual std::string finish_structure()¶
Finish visiting a nested structure.
Associate a node with an id.
No node may be used as an attribute unless it has already been registered with an ID. References to nodes are visited with a ValueAccessor of their ID.
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virtual std::shared_ptr<Node> get_registered_node(node_id_t id)¶
Returns the node with the given id, or nullptr if there is no registered node.
Returns the id for the node, or -1 if the node is not registered.
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virtual void on_adapter(const std::string &name, ValueAccessor<void> &adapter) = 0¶