Swift: Deprecate BarrierGuard.

Author: aschackmull

swift/ql/lib/codeql/swift/dataflow/internal/DataFlowPublic.qll

@@ -153,22 +153,10 @@ class ContentSet extends Content {
 }
 
 /**
- * A guard that validates some expression.
- *
- * To use this in a configuration, extend the class and provide a
- * characteristic predicate precisely specifying the guard, and override
- * `checks` to specify what is being validated and in which branch.
- *
- * It is important that all extending classes in scope are disjoint.
+ * DEPRECATED: Do not use.
  */
-abstract class BarrierGuard extends DataFlowExpr {
+abstract deprecated class BarrierGuard extends DataFlowExpr {
   BarrierGuard() { none() }
 
-  /** Holds if this guard controls block `b` upon evaluating to `branch`. */
-  private predicate controlsBlock(BasicBlock bb, boolean branch) { none() }
-
-  /** Holds if this guard validates `expr` upon evaluating to `branch`. */
-  abstract predicate checks(ControlFlowNode expr, boolean branch);
-
   final Node getAGuardedNode() { none() }
 }

swift/ql/lib/codeql/swift/dataflow/internal/TaintTrackingPrivate.qll

@@ -9,12 +9,6 @@ private import codeql.swift.dataflow.DataFlow
  */
 predicate defaultTaintSanitizer(DataFlow::Node node) { none() }
 
-/**
- * Holds if `guard` should be a sanitizer guard in all global taint flow configurations
- * but not in local taint.
- */
-predicate defaultTaintSanitizerGuard(DataFlow::BarrierGuard guard) { none() }
-
 cached
 private module Cached {
   /**