RelayViz Graphviz renderer

Following apache#10085, this PR adds a
graphviz backend. It requires python `graphviz` package and `dot`
executable in the PATH, similar to `tedd.py`.

This implementation is much like a porting of `visualize` function in
https://tvm.apache.org/2020/07/14/bert-pytorch-tvm, except that
`node_attr_dict` is replaced with a callback `get_node_attr`.

`get_node_attr` can be somehow used to emphasize a set of nodes.
It might be useful if we encounter problems in inferences
and want to find nodes with certain types and attributes.

An example is provided in
https://github.com/chiwwang/tvm/blob/graphviz_renderer_example/test_viz.py

Its outputs are (conv2d with NCHW layout is green-colored):
https://github.com/chiwwang/tvm/blob/graphviz_renderer_example/mod_with_subgraph.pdf
https://github.com/chiwwang/tvm/blob/graphviz_renderer_example/mod_wo_subgraph.pdf

docs/reference/api/python/contrib.rst

@@ -97,10 +97,12 @@ tvm.contrib.relay_viz
 ~~~~~~~~~~~~~~~~~~~~~
 .. automodule:: tvm.contrib.relay_viz
     :members:
-.. automodule:: tvm.contrib.relay_viz.interface
+.. automodule:: tvm.contrib.relay_viz.dot
     :members:
 .. automodule:: tvm.contrib.relay_viz.terminal
     :members:
+.. automodule:: tvm.contrib.relay_viz.interface
+    :members:
 
 
 tvm.contrib.rocblas

gallery/how_to/work_with_relay/using_relay_viz.py

@@ -32,6 +32,8 @@
 Here we use a renderer rendering graph in the text-form.
 It is a lightweight, AST-like visualizer, inspired by `clang ast-dump <https://clang.llvm.org/docs/IntroductionToTheClangAST.html>`_.
 We will introduce how to implement customized parsers and renderers through interface classes.
+
+For more details, please refer to :py:mod:`tvm.contrib.relay_viz`.
 """
 from typing import (
     Dict,

python/tvm/contrib/relay_viz/__init__.py

@@ -27,6 +27,10 @@
     TermPlotter,
     TermVizParser,
 )
+from .dot import (
+    DotPlotter,
+    DotVizParser,
+)
 
 
 class RelayVisualizer:
@@ -69,12 +73,16 @@ def __init__(
 
         node_to_id = {}
         # callback to generate an unique string-ID for nodes.
+        # node_count_offset ensure each node ID is still unique across subgraph.
+        node_count_offset = 0
+
         def traverse_expr(node):
             if node in node_to_id:
                 return
-            node_to_id[node] = str(len(node_to_id))
+            node_to_id[node] = str(len(node_to_id) + node_count_offset)
 
         for name in graph_names:
+            node_count_offset += len(node_to_id)
             node_to_id.clear()
             relay.analysis.post_order_visit(relay_mod[name], traverse_expr)
             graph = self._plotter.create_graph(name)

python/tvm/contrib/relay_viz/dot.py

@@ -0,0 +1,221 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+"""Visualize Relay IR by Graphviz DOT language."""
+
+from typing import (
+    Any,
+    Callable,
+    Dict,
+)
+from .interface import (
+    DefaultVizParser,
+    Plotter,
+    VizEdge,
+    VizGraph,
+    VizNode,
+)
+
+try:
+    import graphviz
+except ImportError:
+    # add "from None" to silence
+    # "During handling of the above exception, another exception occurred"
+    raise ImportError(
+        "The graphviz package is required for DOT renderer. "
+        "Please install it first. For example, pip3 install graphviz"
+    ) from None
+
+DotVizParser = DefaultVizParser
+
+
+class DotGraph(VizGraph):
+    """DOT graph for relay IR.
+
+    See also :py:class:`tvm.contrib.relay_viz.dot.DotPlotter`
+
+    Parameters
+    ----------
+    name: str
+        name of this graph.
+    graph_attr: Optional[Dict[str, str]]
+        key-value pairs for the graph.
+    node_attr: Optional[Dict[str, str]]
+        key-value pairs for all nodes.
+    edge_attr: Optional[Dict[str, str]]
+        key-value pairs for all edges.
+    get_node_attr: Optional[Callable[[VizNode], Dict[str, str]]]
+        A callable returning attributes for the node.
+    """
+
+    def __init__(
+        self,
+        name: str,
+        graph_attr: Dict[str, str] = None,
+        node_attr: Dict[str, str] = None,
+        edge_attr: Dict[str, str] = None,
+        get_node_attr: Callable[[VizNode], Dict[str, str]] = None,
+    ):
+        self._name = name
+        self._get_node_attr = self._default_get_node_attr
+        if get_node_attr is not None:
+            self._get_node_attr = get_node_attr
+
+        # graphviz recognizes the subgraph as a cluster subgraph
+        # by the name starting with "cluster" (all lowercase)
+        self._digraph = graphviz.Digraph(
+            name=f"cluster_{self._name}",
+            graph_attr=graph_attr,
+            node_attr=node_attr,
+            edge_attr=edge_attr,
+        )
+        self._digraph.attr(label=self._name)
+
+    def node(self, viz_node: VizNode) -> None:
+        """Add a node to the underlying graph.
+        Nodes in a Relay IR Module are expected to be added in the post-order.
+
+        Parameters
+        ----------
+        viz_node : VizNode
+            A `VizNode` instance.
+        """
+        self._digraph.node(
+            viz_node.identity,
+            f"{viz_node.type_name}\n{viz_node.detail}",
+            **self._get_node_attr(viz_node),
+        )
+
+    def edge(self, viz_edge: VizEdge) -> None:
+        """Add an edge to the underlying graph.
+
+        Parameters
+        ----------
+        viz_edge : VizEdge
+            A `VizEdge` instance.
+        """
+        self._digraph.edge(viz_edge.start, viz_edge.end)
+
+    @property
+    def digraph(self):
+        return self._digraph
+
+    @staticmethod
+    def _default_get_node_attr(node: VizNode):
+        if "Var" in node.type_name:
+            return {"shape": "ellipse"}
+        return {"shape": "box"}
+
+
+class DotPlotter(Plotter):
+    """DOT language graph plotter
+
+    The plotter accepts various graphviz attributes for graphs, nodes, and edges.
+    Please refer to https://graphviz.org/doc/info/attrs.html for available attributes.
+
+    Parameters
+    ----------
+    graph_attr: Optional[Dict[str, str]]
+        key-value pairs for all graphs.
+    node_attr: Optional[Dict[str, str]]
+        key-value pairs for all nodes.
+    edge_attr: Optional[Dict[str, str]]
+        key-value pairs for all edges.
+    get_node_attr: Optional[Callable[[VizNode], Dict[str, str]]]
+        A callable returning attributes for a specific node.
+    render_kwargs: Optional[Dict[str, Any]]
+        keyword arguments directly passed to `graphviz.Digraph.render()`.
+
+    Examples
+    --------
+
+    .. code-block:: python
+
+        from tvm.contrib import relay_viz
+        from tvm.relay.testing import resnet
+
+        mod, param = resnet.get_workload(num_layers=18)
+        # graphviz attributes
+        graph_attr = {"color": "red"}
+        node_attr = {"color": "blue"}
+        edge_attr = {"color": "black"}
+
+        # VizNode is passed to the callback.
+        # We want to color NCHW conv2d nodes. Also give Var a different shape.
+        def get_node_attr(node):
+            if "nn.conv2d" in node.type_name and "NCHW" in node.detail:
+                return {
+                    "fillcolor": "green",
+                    "style": "filled",
+                    "shape": "box",
+                }
+            if "Var" in node.type_name:
+                return {"shape": "ellipse"}
+            return {"shape": "box"}
+
+        # Create plotter and pass it to viz. Then render the graph.
+        dot_plotter = relay_viz.DotPlotter(
+            graph_attr=graph_attr,
+            node_attr=node_attr,
+            edge_attr=edge_attr,
+            get_node_attr=get_node_attr)
+
+        viz = relay_viz.RelayVisualizer(
+            mod,
+            relay_param=param,
+            plotter=dot_plotter,
+            parser=relay_viz.DotVizParser())
+        viz.render("hello")
+    """
+
+    def __init__(
+        self,
+        graph_attr: Dict[str, str] = None,
+        node_attr: Dict[str, str] = None,
+        edge_attr: Dict[str, str] = None,
+        get_node_attr: Callable[[VizNode], Dict[str, str]] = None,
+        render_kwargs: Dict[str, Any] = None,
+    ):
+        self._name_to_graph = {}
+        self._graph_attr = graph_attr
+        self._node_attr = node_attr
+        self._edge_attr = edge_attr
+        self._get_node_attr = get_node_attr
+
+        self._render_kwargs = {} if render_kwargs is None else render_kwargs
+
+    def create_graph(self, name):
+        self._name_to_graph[name] = DotGraph(
+            name, self._graph_attr, self._node_attr, self._edge_attr, self._get_node_attr
+        )
+        return self._name_to_graph[name]
+
+    def render(self, filename: str = None):
+        """render the graph generated from the Relay IR module.
+
+        This function is a thin wrapper of `graphviz.Digraph.render()`.
+        """
+        # Create or update the filename
+        if filename is not None:
+            self._render_kwargs["filename"] = filename
+        # default cleanup
+        if "cleanup" not in self._render_kwargs:
+            self._render_kwargs["cleanup"] = True
+
+        root_graph = graphviz.Digraph()
+        for graph in self._name_to_graph.values():
+            root_graph.subgraph(graph.digraph)
+        root_graph.render(**self._render_kwargs)

python/tvm/contrib/relay_viz/interface.py

@@ -48,7 +48,7 @@ def __init__(self, node_id: str, node_type: str, node_detail: str):
         self._detail = node_detail
 
     @property
-    def identity(self) -> Union[int, str]:
+    def identity(self) -> str:
         return self._id
 
     @property
@@ -59,6 +59,10 @@ def type_name(self) -> str:
     def detail(self) -> str:
         return self._detail
 
+    def __repr__(self) -> str:
+        detail = self._detail.replace("\n", ", ")
+        return f"VizNode(identity: {self._id}, type_name: {self._type}, detail: {detail}"
+
 
 class VizEdge:
     """VizEdge connect two `VizNode`.
@@ -139,7 +143,7 @@ def edge(self, viz_edge: VizEdge) -> None:
 
         Parameters
         ----------
-        id_start : VizEdge
+        viz_edge : VizEdge
             A `VizEdge` instance.
         """
 
@@ -277,7 +281,7 @@ def _tuple_get_item(
         node_id = node_to_id[node]
 
         # Tuple -> TupleGetItemNode
-        viz_node = VizNode(node_id, f"TupleGetItem", "idx: {node.index}")
+        viz_node = VizNode(node_id, f"TupleGetItem", f"idx: {node.index}")
         viz_edges = [VizEdge(node_to_id[node.tuple_value], node_id)]
         return viz_node, viz_edges
 

python/tvm/contrib/relay_viz/terminal.py

@@ -31,10 +31,11 @@
     VizEdge,
     VizGraph,
     VizNode,
+    VizParser,
 )
 
 
-class TermVizParser(DefaultVizParser):
+class TermVizParser(VizParser):
     """`TermVizParser` parse nodes and edges for `TermPlotter`."""
 
     def __init__(self):
@@ -166,7 +167,7 @@ def edge(self, viz_edge: VizEdge) -> None:
 
         Parameters
         ----------
-        id_start : VizEdge
+        viz_edge : VizEdge
             A `VizEdge` instance.
         """
         # Take CallNode as an example, instead of "arguments point to CallNode",