Java: Add expanded arguments

java/ql/lib/config/semmlecode.dbscheme

@@ -60,6 +60,19 @@ compilation_args(
     string arg : string ref
 );
 
+/**
+ * The expanded arguments that were passed to the extractor for a
+ * compiler invocation. This is similar to `compilation_args`, but
+ * for a `@@@someFile` argument, it includes the arguments from that
+ * file, rather than just taking the argument literally.
+ */
+#keyset[id, num]
+compilation_expanded_args(
+    int id : @compilation ref,
+    int num : int ref,
+    string arg : string ref
+);
+
 /**
  * The source files that are compiled by a compiler invocation.
  * If `id` is for the compiler invocation

java/ql/lib/semmle/code/java/Compilation.qll

@@ -83,6 +83,16 @@ class Compilation extends @compilation {
    */
   string getArgument(int i) { compilation_args(this, i, result) }
 
+  /**
+   * Gets an expanded argument passed to the extractor on this invocation.
+   */
+  string getAnExpandedArgument() { result = getExpandedArgument(_) }
+
+  /**
+   * Gets the `i`th expanded argument passed to the extractor on this invocation.
+   */
+  string getExpandedArgument(int i) { compilation_expanded_args(this, i, result) }
+
   /**
    * Gets the total amount of CPU time spent processing all the files in the
    * compiler.