Implement default action override for BMv2 STF.

p4lang · Nov 10, 2022 · 856c781 · 856c781
1 parent c59597f
commit 856c781
Show file tree

Hide file tree

Showing 5 changed files with 246 additions and 81 deletions.
diff --git a/backends/p4tools/testgen/core/small_step/table_stepper.cpp b/backends/p4tools/testgen/core/small_step/table_stepper.cpp
@@ -90,10 +90,7 @@ bool TableStepper::compareLPMEntries(const IR::Entry* leftIn, const IR::Entry* r
         if (const auto* rightMask = right->checkedTo<IR::Mask>()) {
             rightMaskVal = rightMask->right->checkedTo<IR::Constant>();
         }
-        if ((leftMaskVal->value) < (rightMaskVal->value)) {
-            return false;
-        }
-        return true;
+        return (leftMaskVal->value) >= (rightMaskVal->value);
     }
 
     BUG("Unhandled sort elements type: left: %1% - %2% \n right: %3% - %4% ", left,
@@ -158,10 +155,8 @@ const IR::Expression* TableStepper::computeTargetMatchType(
     TESTGEN_UNIMPLEMENTED("Match type %s not implemented for table keys.", keyProperties.matchType);
 }
 
-const IR::Expression* TableStepper::computeHit(ExecutionState* nextState, const IR::P4Table* table,
+const IR::Expression* TableStepper::computeHit(ExecutionState* nextState,
                                                std::map<cstring, const FieldMatch>* matches) {
-    const auto* key = table->getKey();
-    CHECK_NULL(key);
     const IR::Expression* hitCondition = IR::getBoolLiteral(!properties.resolvedKeys.empty());
     for (auto keyProperties : properties.resolvedKeys) {
         hitCondition = computeTargetMatchType(nextState, keyProperties, matches, hitCondition);
@@ -200,10 +195,7 @@ const IR::Expression* TableStepper::evalTableConstEntries() {
     const IR::Expression* tableMissCondition = IR::getBoolLiteral(true);
 
     const auto* keys = table->getKey();
-    if (keys == nullptr) {
-        // No keys to match on. Assume just the default action will be executed.
-        return tableMissCondition;
-    }
+    BUG_CHECK(keys != nullptr, "An empty key list should have been handled earlier.");
 
     const auto* entries = table->getEntries();
     // Sometimes, there are no entries. Just return.
@@ -309,13 +301,75 @@ const IR::Expression* TableStepper::evalTableConstEntries() {
     return tableMissCondition;
 }
 
+void TableStepper::setTableDefaultEntries(
+    const std::vector<const IR::ActionListElement*>& tableActionList) {
+    for (size_t idx = 0; idx < tableActionList.size(); idx++) {
+        const auto* action = tableActionList.at(idx);
+        // Grab the path from the method call.
+        const auto* tableAction = action->expression->checkedTo<IR::MethodCallExpression>();
+        // Try to find the action declaration corresponding to the path reference in the table.
+        const auto* actionType = stepper->state.getActionDecl(tableAction->method);
+        CHECK_NULL(actionType);
+
+        auto* nextState = new ExecutionState(stepper->state);
+
+        // We get the control plane name of the action we are calling.
+        cstring actionName = actionType->controlPlaneName();
+        // Synthesize arguments for the call based on the action parameters.
+        const auto& parameters = actionType->parameters;
+        auto* arguments = new IR::Vector<IR::Argument>();
+        std::vector<ActionArg> ctrlPlaneArgs;
+        for (size_t argIdx = 0; argIdx < parameters->size(); ++argIdx) {
+            const auto* parameter = parameters->getParameter(argIdx);
+            // Synthesize a zombie constant here that corresponds to a control plane argument.
+            // We get the unique name of the table coupled with the unique name of the action.
+            // Getting the unique name is needed to avoid generating duplicate arguments.
+            const auto& actionDataVar =
+                Utils::getZombieTableVar(parameter->type, table, "*actionData", idx, argIdx);
+            cstring paramName =
+                properties.tableName + "_arg_" + actionName + std::to_string(argIdx);
+            const auto& actionArg = nextState->createZombieConst(parameter->type, paramName);
+            nextState->set(actionDataVar, actionArg);
+            arguments->push_back(new IR::Argument(actionArg));
+            // We also track the argument we synthesize for the control plane.
+            // Note how we use the control plane name for the parameter here.
+            ctrlPlaneArgs.emplace_back(parameter, actionArg);
+        }
+        const auto* ctrlPlaneActionCall = new ActionCall(actionType, ctrlPlaneArgs);
+
+        // We add the arguments to our action call, effectively creating a const entry call.
+        auto* synthesizedAction = tableAction->clone();
+        synthesizedAction->arguments = arguments;
+
+        // We need to set the table action in the state for eventual switch action_run hits.
+        // We also will need it for control plane table entries.
+        setTableAction(nextState, tableAction);
+
+        // Finally, add all the new rules to the execution stepper->state.
+        auto* tableConfig = new TableConfig(table, {});
+        // Add the action selector to the table. This signifies a slightly different implementation.
+        tableConfig->addTableProperty("overriden_default_action", ctrlPlaneActionCall);
+        nextState->addTestObject("tableconfigs", properties.tableName, tableConfig);
+
+        // Update all the tracking variables for tables.
+        std::vector<Continuation::Command> replacements;
+        replacements.emplace_back(new IR::MethodCallStatement(synthesizedAction));
+
+        nextState->set(getTableHitVar(table), IR::getBoolLiteral(false));
+        nextState->set(getTableReachedVar(table), IR::getBoolLiteral(true));
+        std::stringstream tableStream;
+        tableStream << "Table Branch: " << properties.tableName;
+        tableStream << "| Overriding default action: " << actionName;
+        nextState->add(new TraceEvent::Generic(tableStream.str()));
+        nextState->replaceTopBody(&replacements);
+        stepper->result->emplace_back(nextState);
+    }
+}
+
 void TableStepper::evalTableControlEntries(
     const std::vector<const IR::ActionListElement*>& tableActionList) {
     const auto* keys = table->getKey();
-    // If we have no keys, there is nothing to match.
-    if (keys == nullptr) {
-        return;
-    }
+    BUG_CHECK(keys != nullptr, "An empty key list should have been handled earlier.");
 
     for (size_t idx = 0; idx < tableActionList.size(); idx++) {
         const auto* action = tableActionList.at(idx);
@@ -329,7 +383,7 @@ void TableStepper::evalTableControlEntries(
 
         // First, we compute the hit condition to trigger this particular action call.
         std::map<cstring, const FieldMatch> matches;
-        const auto* hitCondition = computeHit(nextState, table, &matches);
+        const auto* hitCondition = computeHit(nextState, &matches);
 
         // We get the control plane name of the action we are calling.
         cstring actionName = actionType->controlPlaneName();

diff --git a/backends/p4tools/testgen/core/small_step/table_stepper.h b/backends/p4tools/testgen/core/small_step/table_stepper.h
@@ -142,7 +142,7 @@ class TableStepper {
     /// handle constant entries, it is specialized for control plane entries.
     /// The function also tracks the list of field matches created to achieve a  hit. We later use
     /// this to insert table entries using the STF/PTF framework.
-    const IR::Expression* computeHit(ExecutionState* nextState, const IR::P4Table* table,
+    const IR::Expression* computeHit(ExecutionState* nextState,
                                      std::map<cstring, const FieldMatch>* matches);
 
     /// Collects properties that may be set per table. Target back end may have different semantics
@@ -185,6 +185,8 @@ class TableStepper {
     /// execution. How a table is evaluated is target-specific.
     virtual void evalTargetTable(const std::vector<const IR::ActionListElement*>& tableActionList);
 
+    void setTableDefaultEntries(const std::vector<const IR::ActionListElement*>& tableActionList);
+
  public:
     /// Table implementations in P4 are rather flexible. Eval is a delegation function that chooses
     /// the right implementation depending on the properties of the table. For example, immutable

diff --git a/backends/p4tools/testgen/targets/bmv2/backend/stf/stf.cpp b/backends/p4tools/testgen/targets/bmv2/backend/stf/stf.cpp
@@ -50,11 +50,66 @@ inja::json STF::getTrace(const TestSpec* testSpec) {
     return traceList;
 }
 
+void checkForTableActionProfile(inja::json& tblJson, std::map<cstring, cstring>& apAsMap,
+                                const TableConfig* tblConfig) {
+    const auto* apObject = tblConfig->getProperty("action_profile", false);
+    if (apObject != nullptr) {
+        const auto* actionProfile = apObject->checkedTo<Bmv2_V1ModelActionProfile>();
+        tblJson["has_ap"] = true;
+        // Check if we have an Action Selector too.
+        // TODO: Change this to check in ActionSelector with table
+        // property "action_selectors".
+        const auto* asObject = tblConfig->getProperty("action_selector", false);
+        if (asObject != nullptr) {
+            const auto* actionSelector = asObject->checkedTo<Bmv2_V1ModelActionSelector>();
+            apAsMap[actionProfile->getProfileDecl()->controlPlaneName()] =
+                actionSelector->getSelectorDecl()->controlPlaneName();
+            tblJson["has_as"] = true;
+        }
+    }
+}
+
+void collectActionProfiles(const TestSpec* testSpec, inja::json& controlPlaneJson,
+                           std::map<cstring, cstring>& apAsMap) {
+    auto actionProfiles = testSpec->getTestObjectCategory("action_profiles");
+    if (!actionProfiles.empty()) {
+        controlPlaneJson["action_profiles"] = inja::json::array();
+    }
+    for (auto const& testObject : actionProfiles) {
+        const auto* const actionProfile = testObject.second->checkedTo<Bmv2_V1ModelActionProfile>();
+        const auto* actions = actionProfile->getActions();
+        inja::json j;
+        j["profile"] = actionProfile->getProfileDecl()->controlPlaneName();
+        j["actions"] = inja::json::array();
+        for (size_t idx = 0; idx < actions->size(); ++idx) {
+            const auto& action = actions->at(idx);
+            auto actionName = action.first;
+            auto actionArgs = action.second;
+            inja::json a;
+            a["action_name"] = actionName;
+            a["action_idx"] = std::to_string(idx);
+            inja::json b = inja::json::array();
+            for (const auto& actArg : actionArgs) {
+                inja::json c;
+                c["param"] = actArg.getActionParamName().c_str();
+                c["value"] = formatHexExpr(actArg.getEvaluatedValue()).c_str();
+                b.push_back(c);
+            }
+            a["act_args"] = b;
+            j["actions"].push_back(a);
+        }
+        if (apAsMap.find(actionProfile->getProfileDecl()->controlPlaneName()) != apAsMap.end()) {
+            j["selector"] = apAsMap[actionProfile->getProfileDecl()->controlPlaneName()];
+        }
+        controlPlaneJson["action_profiles"].push_back(j);
+    }
+}
+
 inja::json STF::getControlPlane(const TestSpec* testSpec) {
     inja::json controlPlaneJson = inja::json::object();
 
     // Map of actionProfiles and actionSelectors for easy reference.
-    std::map<cstring, cstring> apASMap;
+    std::map<cstring, cstring> apAsMap;
 
     auto tables = testSpec->getTestObjectCategory("tables");
     if (!tables.empty()) {
@@ -79,63 +134,30 @@ inja::json STF::getControlPlane(const TestSpec* testSpec) {
         }
 
         // Action Profile
-        const auto* apObject = tblConfig->getProperty("action_profile", false);
-        const Bmv2_V1ModelActionProfile* actionProfile = nullptr;
-        const Bmv2_V1ModelActionSelector* actionSelector = nullptr;
-        if (apObject != nullptr) {
-            actionProfile = apObject->checkedTo<Bmv2_V1ModelActionProfile>();
-            // Check if we have an Action Selector too.
-            // TODO: Change this to check in ActionSelector with table
-            // property "action_selectors".
-            const auto* asObject = tblConfig->getProperty("action_selector", false);
-            if (asObject != nullptr) {
-                actionSelector = asObject->checkedTo<Bmv2_V1ModelActionSelector>();
-                apASMap[actionProfile->getProfileDecl()->controlPlaneName()] =
-                    actionSelector->getSelectorDecl()->controlPlaneName();
-            }
-        }
-        if (actionProfile != nullptr) {
-            tblJson["has_ap"] = true;
-        }
+        checkForTableActionProfile(tblJson, apAsMap, tblConfig);
 
-        if (actionSelector != nullptr) {
-            tblJson["has_as"] = true;
-        }
-
-        controlPlaneJson["tables"].push_back(tblJson);
-    }
-    auto actionProfiles = testSpec->getTestObjectCategory("action_profiles");
-    if (!actionProfiles.empty()) {
-        controlPlaneJson["action_profiles"] = inja::json::array();
-    }
-    for (auto const& testObject : actionProfiles) {
-        const auto* const actionProfile = testObject.second->checkedTo<Bmv2_V1ModelActionProfile>();
-        const auto* actions = actionProfile->getActions();
-        inja::json j;
-        j["profile"] = actionProfile->getProfileDecl()->controlPlaneName();
-        j["actions"] = inja::json::array();
-        for (size_t idx = 0; idx < actions->size(); ++idx) {
-            const auto& action = actions->at(idx);
-            auto actionName = action.first;
-            auto actionArgs = action.second;
+        const auto* defaultOverrideObj = tblConfig->getProperty("overriden_default_action", false);
+        if (defaultOverrideObj != nullptr) {
+            const auto* defaultAction = defaultOverrideObj->checkedTo<ActionCall>();
             inja::json a;
-            a["action_name"] = actionName;
-            a["action_idx"] = std::to_string(idx);
+            a["action_name"] = defaultAction->getActionName();
+            auto const* actionArgs = defaultAction->getArgs();
             inja::json b = inja::json::array();
-            for (const auto& actArg : actionArgs) {
-                inja::json c;
-                c["param"] = actArg.getActionParamName().c_str();
-                c["value"] = formatHexExpr(actArg.getEvaluatedValue()).c_str();
-                b.push_back(c);
+            for (const auto& actArg : *actionArgs) {
+                inja::json j;
+                j["param"] = actArg.getActionParamName().c_str();
+                j["value"] = formatHexExpr(actArg.getEvaluatedValue());
+                b.push_back(j);
             }
-            a["action_args"] = b;
-            j["actions"].push_back(a);
+            a["act_args"] = b;
+            tblJson["default_override"] = a;
         }
-        if (apASMap.find(actionProfile->getProfileDecl()->controlPlaneName()) != apASMap.end()) {
-            j["selector"] = apASMap[actionProfile->getProfileDecl()->controlPlaneName()];
-        }
-        controlPlaneJson["action_profiles"].push_back(j);
+
+        controlPlaneJson["tables"].push_back(tblJson);
     }
+
+    collectActionProfiles(testSpec, controlPlaneJson, apAsMap);
+
     return controlPlaneJson;
 }
 
@@ -302,9 +324,14 @@ static std::string getTestCase() {
 ## if control_plane
 ## for table in control_plane.tables
 # Table {{table.table_name}}
+## if existsIn(table, "default_override")
+setdefault {{table.table_name}} {{table.default_override.action_name}}({% for a in table.default_override.act_args %}{{a.param}}:{{a.value}}{% if not loop.is_last %},{% endif %}{% endfor %})
+## else
 ## for rule in table.rules
 add {{table.table_name}} {% if rule.rules.needs_priority %}{{rule.priority}} {% endif %}{% for r in rule.rules.matches %}{{r.field_name}}:{{r.value}} {% endfor %}{{rule.action_name}}({% for a in rule.rules.act_args %}{{a.param}}:{{a.value}}{% if not loop.is_last %},{% endif %}{% endfor %})
 ## endfor
+## endif
+
 ## endfor
 ## endif
 

diff --git a/backends/p4tools/testgen/targets/bmv2/table_stepper.cpp b/backends/p4tools/testgen/targets/bmv2/table_stepper.cpp
@@ -69,11 +69,6 @@ const IR::Expression* BMv2_V1ModelTableStepper::computeTargetMatchType(
 
 void BMv2_V1ModelTableStepper::evalTableActionProfile(
     const std::vector<const IR::ActionListElement*>& tableActionList) {
-    const auto* keys = table->getKey();
-    // If we have no keys, there is nothing to match.
-    if (keys == nullptr) {
-        return;
-    }
     const auto* state = getExecutionState();
 
     for (size_t idx = 0; idx < tableActionList.size(); idx++) {
@@ -123,7 +118,7 @@ void BMv2_V1ModelTableStepper::evalTableActionProfile(
 
         // Now we compute the hit condition to trigger this particular action call.
         std::map<cstring, const FieldMatch> matches;
-        const auto* hitCondition = computeHit(nextState, table, &matches);
+        const auto* hitCondition = computeHit(nextState, &matches);
 
         // We need to set the table action in the state for eventual switch action_run hits.
         // We also will need it for control plane table entries.
@@ -157,11 +152,6 @@ void BMv2_V1ModelTableStepper::evalTableActionProfile(
 
 void BMv2_V1ModelTableStepper::evalTableActionSelector(
     const std::vector<const IR::ActionListElement*>& tableActionList) {
-    const auto* keys = table->getKey();
-    // If we have no keys, there is nothing to match.
-    if (keys == nullptr) {
-        return;
-    }
     const auto* state = getExecutionState();
 
     for (size_t idx = 0; idx < tableActionList.size(); idx++) {
@@ -220,7 +210,7 @@ void BMv2_V1ModelTableStepper::evalTableActionSelector(
 
         // Now we compute the hit condition to trigger this particular action call.
         std::map<cstring, const FieldMatch> matches;
-        const auto* hitCondition = computeHit(nextState, table, &matches);
+        const auto* hitCondition = computeHit(nextState, &matches);
 
         // We need to set the table action in the state for eventual switch action_run hits.
         // We also will need it for control plane table entries.
@@ -371,6 +361,23 @@ void BMv2_V1ModelTableStepper::checkTargetProperties(
 
 void BMv2_V1ModelTableStepper::evalTargetTable(
     const std::vector<const IR::ActionListElement*>& tableActionList) {
+    const auto* keys = table->getKey();
+    // If we have no keys, there is nothing to match.
+    if (keys == nullptr) {
+        // Either override the default action or fall back to executing it.
+        auto testBackend = TestgenOptions::get().testBackend;
+        if (testBackend == "STF") {
+            setTableDefaultEntries(tableActionList);
+        } else {
+            ::warning(
+                "Overriding default actions not supported for test back end %1%. Choosing default "
+                "action",
+                testBackend);
+            addDefaultAction(boost::none);
+        }
+        return;
+    }
+
     // If the table is not constant, the default action can always be executed.
     // This is because we can simply not enter any table entry.
     boost::optional<const IR::Expression*> tableMissCondition = boost::none;