Improvement of p4c-graphs backend (#3268)

* Extended Table-node processing. Added visiting of Key-node and Action-nodes. * parsers -> rewritten, so they now use boost library for generation of graphs graph_visitor -> class implementing functionality: - to create fullGraph in 'dot' format from boost graphs of program blocks - to create fullGraph in predefined 'json' format - to output separate graphs for each program block in 'dot' format (old functionality)
p4lang · May 2, 2022 · c6bd86f · c6bd86f
1 parent bab0301
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diff --git a/BUILD.bazel b/BUILD.bazel
@@ -416,12 +416,14 @@ cc_library(
     srcs = [
         "backends/graphs/controls.cpp",
         "backends/graphs/graphs.cpp",
+        "backends/graphs/graph_visitor.cpp",
         "backends/graphs/p4c-graphs.cpp",
         "backends/graphs/parsers.cpp",
     ],
     hdrs = [
         "backends/graphs/controls.h",
         "backends/graphs/graphs.h",
+        "backends/graphs/graph_visitor.h",
         "backends/graphs/parsers.h",
         "backends/graphs/version.h",
     ],

diff --git a/backends/graphs/CMakeLists.txt b/backends/graphs/CMakeLists.txt
@@ -19,13 +19,15 @@ set (GRAPHS_SRCS
   graphs.cpp
   controls.cpp
   parsers.cpp
+  graph_visitor.cpp
   p4c-graphs.cpp
   )
 
 set (GRAPHS_HDRS
   graphs.h
   controls.h
   parsers.h
+  graph_visitor.h
   )
 
 add_cpplint_files(${CMAKE_CURRENT_SOURCE_DIR} "${GRAPHS_SRCS};${GRAPHS_HDRS}")

diff --git a/backends/graphs/README.md b/backends/graphs/README.md
@@ -1,7 +1,9 @@
 # Graphs Backend
 
 This backend produces visual representations of a P4 program as dot files. For
-now it only supports the generation of graphs for top-level control and parser blocks.
+now it supports the generation of graphs for top-level control and parser blocks,
+generation of fullGraph, which merges graphs for top-level program blocks and
+json representation of fullGraph.
 
 dot files can be processed by the `dot` command from
 [Graphviz](http://graphviz.org), which can lay out the nodes and
@@ -23,6 +25,43 @@ cd out
 dot <name>.dot -Tpng > <name>.png
 ```
 
+For generation of dot fullGraph, use option `--fullGraph` and 
+for generation of fullGraph represented in json, use option `--jsonOut`.
+
+## Format of json output
+
+Output in json format is an object with fields:
+
+- `info` (object)
+
+    - `name` - Filename of P4 program.
+
+- `nodes` (array) - Contains objects, representing program blocks.
+
+    - `type` - Type of program block. Valid values are "parser" and "control".
+
+    - `name` - Name of program block.
+
+    - `nodes` (array) - Contains object, representing nodes of CFG.
+
+        - `node_nmb` - Index of given object in array nodes.
+
+        - `name` - Node label.
+
+        - `type` - Type of node.
+
+        - `type_enum` - Enum value, representing type of node in backend *p4c-graphs*. 
+
+    - `transitions` (array) - Contains objects, representing transitions between nodes in `nodes`.
+
+        - `from` - Index to node in `nodes`, from which edge starts.
+
+        - `to` - Index to node in `nodes`, in which edge ends.
+
+        - `cond` - Edge label.
+
+Objects which represent program blocks are ordered in `nodes`, in the order in which they are defined in the main declaration of P4 program.
+
 ## Example
 
 Here is the graph generated for the ingress control block of the
@@ -31,13 +70,18 @@ test program:
 
 ![Flowlet switching ingress graph](resources/flowlet_switching-bmv2.ingress.png)
 
+Here is the graph generated for the egress control block of the
+[flowlet_switching-bmv2.p4](../../testdata/p4_16_samples/flowlet_switching-bmv2.p4)
+test program:
+
+![Flowlet switching egress graph](resources/flowlet_switching-bmv2.egress.png)
+
 Here is the graph generated for the parser block of the
 [flowlet_switching-bmv2.p4](../../testdata/p4_16_samples/flowlet_switching-bmv2.p4)
 test program:
 
 ![Flowlet switching ingress graph](resources/flowlet_switching-bmv2.parser.png)
 
-For a more complex example, you can look at the control graph generated for the
-egress control of
-[switch.p4](https://github.com/p4lang/switch/tree/f219b4f4e25c2db581f3b91c8da94a7c3ac701a7/p4src)
-[here](http://bmv2.org/switch_egress.png).
+Examples of generated fullGraph for [flowlet_switching-bmv2.p4](../../testdata/p4_16_samples/flowlet_switching-bmv2.p4) program
+and [firewall.p4](https://github.com/p4lang/tutorials/blob/master/exercises/firewall/solution/firewall.p4) program
+can be found in [resources](resources/), also with json fullGraph.
diff --git a/backends/graphs/controls.cpp b/backends/graphs/controls.cpp
@@ -24,7 +24,6 @@ limitations under the License.
 #include "frontends/p4/tableApply.h"
 #include "lib/log.h"
 #include "lib/nullstream.h"
-#include "lib/path.h"
 #include "controls.h"
 
 namespace graphs {
@@ -33,11 +32,12 @@ using Graph = ControlGraphs::Graph;
 
 Graph *ControlGraphs::ControlStack::pushBack(Graph &currentSubgraph, const cstring &name) {
     auto &newSubgraph = currentSubgraph.create_subgraph();
-    boost::get_property(newSubgraph, boost::graph_name) = "cluster" + getName(name);
-    boost::get_property(newSubgraph, boost::graph_graph_attribute)["label"] = getName(name);
-    // Justify the subgraph label to the right as it usually makes the generated
-    // graph more readable than the default (center).
-    boost::get_property(newSubgraph, boost::graph_graph_attribute)["labeljust"] = "r";
+    auto fullName = getName(name);
+    boost::get_property(newSubgraph, boost::graph_name) = "cluster" + fullName;
+    boost::get_property(newSubgraph, boost::graph_graph_attribute)["label"] =
+                    boost::get_property(currentSubgraph, boost::graph_name) +
+                    (fullName != "" ? "." + fullName : fullName);
+    boost::get_property(newSubgraph, boost::graph_graph_attribute)["fontsize"] = "22pt";
     boost::get_property(newSubgraph, boost::graph_graph_attribute)["style"] = "bold";
     names.push_back(name);
     subgraphs.push_back(&newSubgraph);
@@ -75,40 +75,30 @@ ControlGraphs::ControlGraphs(P4::ReferenceMap *refMap, P4::TypeMap *typeMap,
     visitDagOnce = false;
 }
 
-void ControlGraphs::writeGraphToFile(const Graph &g, const cstring &name) {
-    auto path = Util::PathName(graphsDir).join(name + ".dot");
-    auto out = openFile(path.toString(), false);
-    if (out == nullptr) {
-        ::error(ErrorType::ERR_IO, "Failed to open file %1%", path.toString());
-        return;
-    }
-    // custom label writers not supported with subgraphs, so we populate
-    // *_attribute_t properties instead using our GraphAttributeSetter class.
-    boost::write_graphviz(*out, g);
-}
-
 bool ControlGraphs::preorder(const IR::PackageBlock *block) {
     for (auto it : block->constantValue) {
         if (!it.second) continue;
         if (it.second->is<IR::ControlBlock>()) {
             auto name = it.second->to<IR::ControlBlock>()->container->name;
             LOG1("Generating graph for top-level control " << name);
-            Graph g_;
-            g = &g_;
-            BUG_CHECK(controlStack.isEmpty(), "Invalid control stack state");
-            g = controlStack.pushBack(g_, "");
+
+            Graph *g_ = new Graph();
+            g = g_;
             instanceName = boost::none;
-            boost::get_property(g_, boost::graph_name) = name;
+            boost::get_property(*g_, boost::graph_name) = name;
+            BUG_CHECK(controlStack.isEmpty(), "Invalid control stack state");
+            g = controlStack.pushBack(*g_, "");
             start_v = add_vertex("__START__", VertexType::OTHER);
             exit_v = add_vertex("__EXIT__", VertexType::OTHER);
             parents = {{start_v, new EdgeUnconditional()}};
             visit(it.second->getNode());
-            for (auto parent : parents)
+
+            for (auto parent : parents) {
                 add_edge(parent.first, exit_v, parent.second->label());
-            BUG_CHECK(g_.is_root(), "Invalid graph");
+            }
+            BUG_CHECK((*g_).is_root(), "Invalid graph");
             controlStack.popBack();
-            GraphAttributeSetter()(g_);
-            writeGraphToFile(g_, name);
+            controlGraphsArray.push_back(g_);
         } else if (it.second->is<IR::PackageBlock>()) {
             visit(it.second->getNode());
         }
@@ -131,6 +121,7 @@ bool ControlGraphs::preorder(const IR::P4Control *cont) {
     return_parents.clear();
     visit(cont->body);
     merge_other_statements_into_vertex();
+
     parents.insert(parents.end(), return_parents.begin(), return_parents.end());
     return_parents.clear();
     if (doPop) g = controlStack.popBack();
@@ -141,17 +132,20 @@ bool ControlGraphs::preorder(const IR::BlockStatement *statement) {
     for (const auto component : statement->components)
         visit(component);
     merge_other_statements_into_vertex();
+
     return false;
 }
 
 bool ControlGraphs::preorder(const IR::IfStatement *statement) {
     std::stringstream sstream;
     statement->condition->dbprint(sstream);
     auto v = add_and_connect_vertex(cstring(sstream), VertexType::CONDITION);
+
     Parents new_parents;
     parents = {{v, new EdgeIf(EdgeIf::Branch::TRUE)}};
     visit(statement->ifTrue);
     merge_other_statements_into_vertex();
+
     new_parents.insert(new_parents.end(), parents.begin(), parents.end());
     parents = {{v, new EdgeIf(EdgeIf::Branch::FALSE)}};
     if (statement->ifFalse != nullptr) {
@@ -207,6 +201,7 @@ bool ControlGraphs::preorder(const IR::SwitchStatement *statement) {
 
 bool ControlGraphs::preorder(const IR::MethodCallStatement *statement) {
     auto instance = P4::MethodInstance::resolve(statement->methodCall, refMap, typeMap);
+
     if (instance->is<P4::ApplyMethod>()) {
         auto am = instance->to<P4::ApplyMethod>();
         if (am->object->is<IR::P4Table>()) {
@@ -244,23 +239,87 @@ bool ControlGraphs::preorder(const IR::AssignmentStatement *statement) {
 
 bool ControlGraphs::preorder(const IR::ReturnStatement *) {
     merge_other_statements_into_vertex();
+
     return_parents.insert(return_parents.end(), parents.begin(), parents.end());
     parents.clear();
     return false;
 }
 
 bool ControlGraphs::preorder(const IR::ExitStatement *) {
     merge_other_statements_into_vertex();
+
     for (auto parent : parents)
         add_edge(parent.first, exit_v, parent.second->label());
     parents.clear();
     return false;
 }
 
+bool ControlGraphs::preorder(const IR::Key *key) {
+    std::stringstream sstream;
+
+    // Build key
+    for (auto elVec : key->keyElements) {
+        sstream << elVec->matchType->path->name.name << ": ";
+        sstream << elVec->annotations->annotations.front()->expr.front() << "\\n";
+    }
+
+    auto v = add_and_connect_vertex(cstring(sstream), VertexType::KEY);
+
+    parents = {{v, new EdgeUnconditional()}};
+
+    return false;
+}
+
+bool ControlGraphs::preorder(const IR::P4Action *action) {
+    visit(action->body);
+    return false;
+}
+
 bool ControlGraphs::preorder(const IR::P4Table *table) {
-    auto name = controlStack.getName(table->controlPlaneName());
+    auto name = table->getName();
+
     auto v = add_and_connect_vertex(name, VertexType::TABLE);
+
     parents = {{v, new EdgeUnconditional()}};
+
+    auto key = table->getKey();
+    visit(key);
+
+    Parents keyNode;
+    keyNode.emplace_back(parents.back());
+
+    Parents new_parents;
+
+    auto actions = table->getActionList()->actionList;
+    for (auto action : actions){
+        parents = keyNode;
+
+        auto v = add_and_connect_vertex(action->getName(), VertexType::ACTION);
+
+        parents = {{v, new EdgeUnconditional()}};
+
+        if (action->expression->is<IR::MethodCallExpression>()) {
+            auto mce = action->expression->to<IR::MethodCallExpression>();
+
+            // needed for visiting body of P4Action
+            auto resolved = P4::MethodInstance::resolve(mce, refMap, typeMap);
+
+            if (resolved->is<P4::ActionCall>()) {
+                auto ac = resolved->to<P4::ActionCall>();
+                if (ac->action->is<IR::P4Action>()) {
+                    visit(ac->action->to<IR::P4Action>());
+                }
+            }
+        }
+
+        merge_other_statements_into_vertex();
+
+        new_parents.insert(new_parents.end(), parents.begin(), parents.end());
+        parents.clear();
+    }
+
+    parents = new_parents;
+
     return false;
 }
 

diff --git a/backends/graphs/controls.h b/backends/graphs/controls.h
@@ -48,8 +48,10 @@ class ControlGraphs : public Graphs {
     bool preorder(const IR::ReturnStatement *) override;
     bool preorder(const IR::ExitStatement *) override;
     bool preorder(const IR::P4Table *table) override;
+    bool preorder(const IR::Key *key) override;
+    bool preorder(const IR::P4Action *action) override;
 
-    void writeGraphToFile(const Graph &g, const cstring &name);
+    std::vector<Graph *> controlGraphsArray{};
 
  private:
     P4::ReferenceMap *refMap; P4::TypeMap *typeMap;