[Clava-JS] Reformulates the ClavaBenchmarkInstance interface

- Now is an abstract class, provides implementations for loadPrivate() and closePrivate(), and adds protected abstract methods loadPrologue(), addCode(), and closeEpilogue();

Clava-JS/src-api/lara/benchmark/ClavaBenchmarkInstance.ts

@@ -4,15 +4,16 @@ import { JavaClasses } from "lara-js/api/lara/util/JavaTypes.js";
 import Query from "lara-js/api/weaver/Query.js";
 import Weaver from "lara-js/api/weaver/Weaver.js";
 import Clava from "../..//clava/Clava.js";
-import { Pragma, Program } from "../../Joinpoints.js";
+import { Joinpoint, Pragma, Program } from "../../Joinpoints.js";
 import CMaker from "../../clava/cmake/CMaker.js";
+import ClavaJoinPoints from "../../clava/ClavaJoinPoints.js";
 
 /**
  * Instance of a Clava benchmark.
  *
  * Implements _compilePrivate and .getKernel().
  */
-export default class ClavaBenchmarkInstance extends BenchmarkInstance {
+export default abstract class ClavaBenchmarkInstance extends BenchmarkInstance {
   /**
    * The output folder for this BenchmarkInstance.
    */
@@ -51,9 +52,36 @@ export default class ClavaBenchmarkInstance extends BenchmarkInstance {
     return exe;
   }
 
-  protected loadPrivate(): void {}
 
-  protected closePrivate(): void {}
+
+
+  /**
+   * Speciallized implementation for Clava that automatically saves and restores the AST, extending classes just need to implement addCode() and loadPrologue().
+   */
+  protected loadPrivate(): void {
+    // Execute configuration for current instance
+    this.loadPrologue();
+
+    // Pust an empty AST to the top of the stack
+    Clava.pushAst(ClavaJoinPoints.program());
+
+    // Add code
+    this.addCode();
+
+    // Rebuild
+    Clava.rebuild();
+  }
+
+
+  protected closePrivate(): void {
+      // Restore any necessary configurations
+      this.closeEpilogue();
+
+      // Restore previous AST
+      Clava.popAst();
+  }
+
+
 
   protected loadCached(astFile: JavaClasses.File) {
     // eslint-disable-next-line @typescript-eslint/no-unsafe-call
@@ -78,4 +106,23 @@ export default class ClavaBenchmarkInstance extends BenchmarkInstance {
 
     return $pragma.target;
   }
+
+
+  /*** FUNCTIONS TO IMPLEMENT ***/
+
+  /**
+   * Configuration that is required by the benchmarks (e.g., setting the standard)
+   */
+  protected abstract loadPrologue(): void;
+
+  /**
+   * Adds the code to the AST, can assume the AST is empty.
+   */
+  protected abstract addCode(): void;
+
+  /**
+   * 
+   */
+  protected abstract closeEpilogue(): void;
+
 }