[P4Testgen] Clean up the implementation of the BMv2 clone externs. (#…

…3976)

* Clean up the implementation of the BMv2 clone implementation. Use explicit info objects to maintain state.

* A different clone id is not needed. Instead, we should fix PI.

* Update the session ID maximum.

* Merge fixes.

backends/p4tools/modules/testgen/core/small_step/extern_stepper.cpp

@@ -4,6 +4,7 @@
 #include <optional>
 #include <ostream>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include <boost/multiprecision/cpp_int.hpp>

backends/p4tools/modules/testgen/lib/execution_state.cpp

@@ -3,6 +3,7 @@
 #include <algorithm>
 #include <cstddef>
 #include <initializer_list>
+#include <list>
 #include <map>
 #include <stack>
 #include <string>
@@ -25,6 +26,7 @@
 #include "ir/irutils.h"
 #include "lib/log.h"
 #include "lib/null.h"
+#include "lib/ordered_map.h"
 #include "lib/source_file.h"
 
 #include "backends/p4tools/modules/testgen/lib/continuation.h"
@@ -193,15 +195,24 @@ const TestObject *ExecutionState::getTestObject(cstring category, cstring object
     return nullptr;
 }
 
-std::map<cstring, const TestObject *> ExecutionState::getTestObjectCategory(
-    cstring category) const {
+TestObjectMap ExecutionState::getTestObjectCategory(cstring category) const {
     auto it = testObjects.find(category);
     if (it != testObjects.end()) {
         return it->second;
     }
     return {};
 }
 
+void ExecutionState::deleteTestObject(cstring category, cstring objectLabel) {
+    auto it = testObjects.find(category);
+    if (it != testObjects.end()) {
+        return;
+    }
+    it->second.erase(objectLabel);
+}
+
+void ExecutionState::deleteTestObjectCategory(cstring category) { testObjects.erase(category); }
+
 void ExecutionState::setReachabilityEngineState(ReachabilityEngineState *newEngineState) {
     reachabilityEngineState = newEngineState;
 }

backends/p4tools/modules/testgen/lib/execution_state.h

@@ -25,7 +25,7 @@
 #include "midend/coverage.h"
 
 #include "backends/p4tools/modules/testgen/lib/continuation.h"
-#include "backends/p4tools/modules/testgen/lib/test_spec.h"
+#include "backends/p4tools/modules/testgen/lib/test_object.h"
 
 namespace P4Tools::P4Testgen {
 
@@ -103,7 +103,7 @@ class ExecutionState {
     // which defines control plane match action entries. Once the interpreter has solved for the
     // variables used by these test objects and concretized the values, they can be used to generate
     // a test. Test objects are not constant because they may be manipulated by a target back end.
-    std::map<cstring, std::map<cstring, const TestObject *>> testObjects;
+    std::map<cstring, TestObjectMap> testObjects;
 
     /// The parserErrorLabel is set by the parser to indicate the variable corresponding to the
     /// parser error that is set by various built-in functions such as verify or extract.
@@ -217,29 +217,37 @@ class ExecutionState {
     [[nodiscard]] const TestObject *getTestObject(cstring category, cstring objectLabel,
                                                   bool checked) const;
 
+    /// Remove a test object from a category.
+    void deleteTestObject(cstring category, cstring objectLabel);
+
+    /// Remove a test category entirely.
+    void deleteTestObjectCategory(cstring category);
+
     /// @returns the uninterpreted test object using the provided category and object label. If
     /// @param checked is enabled, a BUG is thrown if the object label does not exist.
     /// Also casts the test object to the specified type. If the type does not match, a BUG is
     /// thrown.
     template <class T>
-    [[nodiscard]] T *getTestObject(cstring category, cstring objectLabel, bool checked) const {
-        const auto *testObject = getTestObject(category, objectLabel, checked);
+    [[nodiscard]] const T *getTestObject(cstring category, cstring objectLabel) const {
+        const auto *testObject = getTestObject(category, objectLabel, true);
         return testObject->checkedTo<T>();
     }
 
     /// @returns the map of uninterpreted test objects for a specific test category. For example,
     /// all the table entries saved under "tableconfigs".
-    [[nodiscard]] std::map<cstring, const TestObject *> getTestObjectCategory(
-        cstring category) const;
+    [[nodiscard]] TestObjectMap getTestObjectCategory(cstring category) const;
 
+    /// Get the current state of the reachability engine.
     [[nodiscard]] ReachabilityEngineState *getReachabilityEngineState() const;
 
+    /// Update the reachability engine state.
     void setReachabilityEngineState(ReachabilityEngineState *newEngineState);
 
     /* =========================================================================================
      *  Trace events.
      * ========================================================================================= */
  public:
+    /// Add a new trace event to the state.
     void add(const TraceEvent &event);
 
     /* =========================================================================================

backends/p4tools/modules/testgen/lib/test_object.h

@@ -0,0 +1,37 @@
+#ifndef BACKENDS_P4TOOLS_MODULES_TESTGEN_LIB_TEST_OBJECT_H_
+#define BACKENDS_P4TOOLS_MODULES_TESTGEN_LIB_TEST_OBJECT_H_
+#include <map>
+
+#include "backends/p4tools/common/lib/model.h"
+#include "lib/castable.h"
+#include "lib/cstring.h"
+
+namespace P4Tools::P4Testgen {
+
+/* =========================================================================================
+ *  Abstract Test Object Class
+ * ========================================================================================= */
+
+class TestObject : public ICastable {
+ public:
+    TestObject() = default;
+    ~TestObject() override = default;
+    TestObject(const TestObject &) = default;
+    TestObject(TestObject &&) = default;
+    TestObject &operator=(const TestObject &) = default;
+    TestObject &operator=(TestObject &&) = default;
+
+    /// @returns the string name of this particular test object.
+    [[nodiscard]] virtual cstring getObjectName() const = 0;
+
+    /// @returns a version of the test object where all expressions are resolved and symbolic
+    /// variables are substituted according to the mapping present in the @param model.
+    [[nodiscard]] virtual const TestObject *evaluate(const Model &model) const = 0;
+};
+
+/// A map of test objects.
+using TestObjectMap = ordered_map<cstring, const TestObject *>;
+
+}  // namespace P4Tools::P4Testgen
+
+#endif /* BACKENDS_P4TOOLS_MODULES_TESTGEN_LIB_TEST_OBJECT_H_ */

backends/p4tools/modules/testgen/lib/test_spec.cpp

@@ -1,5 +1,6 @@
 #include "backends/p4tools/modules/testgen/lib/test_spec.h"
 
+#include <list>
 #include <map>
 #include <optional>
 #include <utility>
@@ -11,6 +12,7 @@
 #include "backends/p4tools/common/lib/trace_event.h"
 #include "ir/irutils.h"
 #include "lib/exceptions.h"
+#include "lib/ordered_map.h"
 
 namespace P4Tools::P4Testgen {
 
@@ -216,14 +218,12 @@ TableConfig::TableConfig(const IR::P4Table *table, std::vector<TableRule> rules)
     : table(table), rules(std::move(rules)) {}
 
 TableConfig::TableConfig(const IR::P4Table *table, std::vector<TableRule> rules,
-                         std::map<cstring, const TestObject *> tableProperties)
+                         TestObjectMap tableProperties)
     : table(table), rules(std::move(rules)), tableProperties(std::move(tableProperties)) {}
 
 const std::vector<TableRule> *TableConfig::getRules() const { return &rules; }
 
-const std::map<cstring, const TestObject *> *TableConfig::getProperties() const {
-    return &tableProperties;
-}
+const TestObjectMap *TableConfig::getProperties() const { return &tableProperties; }
 
 const TestObject *TableConfig::getProperty(cstring propertyName, bool checked) const {
     auto it = tableProperties.find(propertyName);
@@ -246,7 +246,7 @@ const TableConfig *TableConfig::evaluate(const Model &model) const {
         const auto *evaluatedRule = rule.evaluate(model);
         evaluatedRules.emplace_back(*evaluatedRule);
     }
-    std::map<cstring, const TestObject *> evaluatedProperties;
+    TestObjectMap evaluatedProperties;
     for (const auto &propertyTuple : tableProperties) {
         auto name = propertyTuple.first;
         const auto *property = propertyTuple.second;
@@ -298,7 +298,7 @@ const TestObject *TestSpec::getTestObject(cstring category, cstring objectLabel,
     return nullptr;
 }
 
-std::map<cstring, const TestObject *> TestSpec::getTestObjectCategory(cstring category) const {
+TestObjectMap TestSpec::getTestObjectCategory(cstring category) const {
     auto it = testObjects.find(category);
     if (it != testObjects.end()) {
         return it->second;