Make shared CFG construction library a parameterized module

shared/controlflow/qlpack.yml

@@ -2,4 +2,6 @@ name: codeql/controlflow
 version: 0.0.1-dev
 groups: shared
 library: true
+dependencies:
+  codeql/util: ${workspace}
 warnOnImplicitThis: true

shared/util/codeql/util/Location.qll

@@ -0,0 +1,36 @@
+/** Provides classes for working with locations. */
+
+/**
+ * A location as given by a file, a start line, a start column,
+ * an end line, and an end column.
+ *
+ * For more information about locations see [Locations](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
+ */
+signature class LocationSig {
+  /** Gets the 1-based line number (inclusive) where this location starts. */
+  int getStartLine();
+
+  /** Gets the 1-based column number (inclusive) where this location starts. */
+  int getStartColumn();
+
+  /** Gets the 1-based line number (inclusive) where this location ends. */
+  int getEndLine();
+
+  /** Gets the 1-based column number (inclusive) where this location ends. */
+  int getEndColumn();
+
+  /** Gets a textual representation of this location. */
+  bindingset[this]
+  string toString();
+
+  /**
+   * Holds if this element is at the specified location.
+   * The location spans column `startColumn` of line `startLine` to
+   * column `endColumn` of line `endLine` in file `filepath`.
+   * For more information, see
+   * [Providing locations in CodeQL queries](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
+   */
+  predicate hasLocationInfo(
+    string filePath, int startLine, int startColumn, int endLine, int endColumn
+  );
+}