Respond to review comments.

cpp/ql/lib/semmle/code/cpp/models/implementations/PostgreSql.qll

@@ -71,8 +71,8 @@ private class PostgreSqlExecutionFunction extends SqlExecutionFunction {
   }
 }
 
-private class PostgreSqlEscapeFunction extends SqlEscapeFunction {
-  PostgreSqlEscapeFunction() {
+private class PostgreSqlBarrierFunction extends SqlBarrierFunction {
+  PostgreSqlBarrierFunction() {
     exists(Class c |
       this.getDeclaringType() = c and
       // transaction and connection escape functions
@@ -84,7 +84,7 @@ private class PostgreSqlEscapeFunction extends SqlEscapeFunction {
     )
   }
 
-  override predicate escapesSqlArgument(FunctionInput input, FunctionOutput output) {
+  override predicate barrierSqlArgument(FunctionInput input, FunctionOutput output) {
     exists(int argIndex |
       input.isParameterDeref(argIndex) and
       output.isReturnValueDeref() and

cpp/ql/lib/semmle/code/cpp/models/interfaces/Sql.qll

@@ -1,6 +1,6 @@
 /**
  * Provides abstract classes for modeling functions that execute and escape SQL query strings.
- * To use this QL library, create a QL class extending `SqlExecutionFunction` or `SqlEscapeFunction`
+ * To extend this QL library, create a QL class extending `SqlExecutionFunction` or `SqlEscapeFunction`
  * with a characteristic predicate that selects the function or set of functions you are modeling.
  * Within that class, override the predicates provided by the class to match the way a
  * parameter flows into the function and, in the case of `SqlEscapeFunction`, out of the function.
@@ -21,10 +21,10 @@ abstract class SqlExecutionFunction extends Function {
 /**
  * An abstract class that represents a function that escapes an SQL query string.
  */
-abstract class SqlEscapeFunction extends Function {
+abstract class SqlBarrierFunction extends Function {
   /**
-   * Holds if the `output` escapes the SQL input `input` such that is it safe to pass to
+   * Holds if the `output` is a barrier to the SQL input `input` such that is it safe to pass to
    * an `SqlExecutionFunction`.
    */
-  abstract predicate escapesSqlArgument(FunctionInput input, FunctionOutput output);
+  abstract predicate barrierSqlArgument(FunctionInput input, FunctionOutput output);
 }

cpp/ql/src/Security/CWE/CWE-089/SqlTainted.ql

@@ -34,10 +34,10 @@ class Configuration extends TaintTrackingConfiguration {
     or
     e.getUnspecifiedType() instanceof IntegralType
     or
-    exists(SqlEscapeFunction sql, int arg, FunctionInput input |
+    exists(SqlBarrierFunction sql, int arg, FunctionInput input |
       e = sql.getACallToThisFunction().getArgument(arg) and
       input.isParameterDeref(arg) and
-      sql.escapesSqlArgument(input, _)
+      sql.barrierSqlArgument(input, _)
     )
   }
 }