Shared: Add approximate version of getASelected{Source,Sink}Location

Author: asgerf

shared/dataflow/codeql/dataflow/DataFlow.qll

@@ -457,6 +457,15 @@ module Configs<LocationSig Location, InputSig<Location> Lang> {
      */
     default Location getASelectedSourceLocation(Node source) { result = source.getLocation() }
 
+    /**
+     * Like `getASelectedSourceLocation`, but only has to get a location _containing_ the
+     * actual location associated with `source`.
+     *
+     * This prunes fewer sources than `getASelectedSourceLocation` but leaves room for the possibility
+     * that a more precise location can be selected in the query.
+     */
+    default Location getASelectedSourceLocationApprox(Node source) { none() }
+
     /**
      * Gets a location that will be associated with the given `sink` in a
      * diff-informed query that uses this configuration (see
@@ -467,6 +476,15 @@ module Configs<LocationSig Location, InputSig<Location> Lang> {
      * report the sink at all, this predicate can be `none()`.
      */
     default Location getASelectedSinkLocation(Node sink) { result = sink.getLocation() }
+
+    /**
+     * Like `getASelectedSinkLocation`, but only has to get a location _containing_ the
+     * actual location associated with `sink`.
+     *
+     * This prunes fewer sinks than `getASelectedSinkLocation` but leaves room for the possibility
+     * that a more precise location can be selected in the query.
+     */
+    default Location getASelectedSinkLocationApprox(Node sink) { none() }
   }
 
   /** An input configuration for data flow using flow state. */
@@ -606,6 +624,15 @@ module Configs<LocationSig Location, InputSig<Location> Lang> {
      */
     default Location getASelectedSourceLocation(Node source) { result = source.getLocation() }
 
+    /**
+     * Like `getASelectedSourceLocation`, but only has to get a location _containing_ the
+     * actual location associated with `source`.
+     *
+     * This prunes fewer sources than `getASelectedSourceLocation` but leaves room for the possibility
+     * that a more precise location can be selected in the query.
+     */
+    default Location getASelectedSourceLocationApprox(Node source) { none() }
+
     /**
      * Gets a location that will be associated with the given `sink` in a
      * diff-informed query that uses this configuration (see
@@ -616,6 +643,15 @@ module Configs<LocationSig Location, InputSig<Location> Lang> {
      * report the sink at all, this predicate can be `none()`.
      */
     default Location getASelectedSinkLocation(Node sink) { result = sink.getLocation() }
+
+    /**
+     * Like `getASelectedSinkLocation`, but only has to get a location _containing_ the
+     * actual location associated with `sink`.
+     *
+     * This prunes fewer sinks than `getASelectedSinkLocation` but leaves room for the possibility
+     * that a more precise location can be selected in the query.
+     */
+    default Location getASelectedSinkLocationApprox(Node sink) { none() }
   }
 }
 

shared/dataflow/codeql/dataflow/internal/DataFlowImpl.qll

@@ -143,7 +143,11 @@ module MakeImpl<LocationSig Location, InputSig<Location> Lang> {
 
     Location getASelectedSourceLocation(Node source);
 
+    Location getASelectedSourceLocationApprox(Node source);
+
     Location getASelectedSinkLocation(Node sink);
+
+    Location getASelectedSinkLocationApprox(Node sink);
   }
 
   /**

shared/dataflow/codeql/dataflow/internal/DataFlowImplStage1.qll

@@ -131,7 +131,9 @@ module MakeImplStage1<LocationSig Location, InputSig<Location> Lang> {
       private predicate isFilteredSource(Node source) {
         Config::isSource(source, _) and
         if Config::observeDiffInformedIncrementalMode()
-        then AlertFiltering::filterByLocation(Config::getASelectedSourceLocation(source))
+        then
+          AlertFiltering::filterByLocation(Config::getASelectedSourceLocation(source)) or
+          AlertFiltering::filterByLocationApprox(Config::getASelectedSourceLocationApprox(source))
         else any()
       }
 
@@ -142,7 +144,9 @@ module MakeImplStage1<LocationSig Location, InputSig<Location> Lang> {
           Config::isSink(sink)
         ) and
         if Config::observeDiffInformedIncrementalMode()
-        then AlertFiltering::filterByLocation(Config::getASelectedSinkLocation(sink))
+        then
+          AlertFiltering::filterByLocation(Config::getASelectedSinkLocation(sink)) or
+          AlertFiltering::filterByLocationApprox(Config::getASelectedSinkLocationApprox(sink))
         else any()
       }
 

shared/util/codeql/util/AlertFiltering.qll

@@ -105,4 +105,40 @@ module AlertFilteringImpl<LocationSig Location> {
       location.hasLocationInfo(filePath, startLine, startColumn, endLine, endColumn)
     )
   }
+
+  /**
+   * Holds if some subrange within `location` would be accepted by alert filtering.
+   *
+   * There does not need to exist a `Location` corresponding to that subrange.
+   */
+  bindingset[location]
+  predicate filterByLocationApprox(Location location) {
+    not restrictAlertsTo(_, _, _) and not restrictAlertsToExactLocation(_, _, _, _, _)
+    or
+    exists(string filePath |
+      restrictAlertsToEntireFile(filePath) and
+      location.hasLocationInfo(filePath, _, _, _, _)
+      or
+      exists(int locStartLine, int locEndLine |
+        location.hasLocationInfo(filePath, locStartLine, _, locEndLine, _)
+      |
+        restrictAlertsToStartLine(filePath, [locStartLine .. locEndLine])
+      )
+    )
+    or
+    // Check if an exact filter-location is fully contained in `location`.
+    // This is slow but only used for testing.
+    exists(
+      string filePath, int startLine, int startColumn, int endLine, int endColumn,
+      int filterStartLine, int filterStartColumn, int filterEndLine, int filterEndColumn
+    |
+      location.hasLocationInfo(filePath, startLine, startColumn, endLine, endColumn) and
+      restrictAlertsToExactLocation(filePath, filterStartLine, filterStartColumn, filterEndLine,
+        filterEndColumn) and
+      startLine <= filterStartLine and
+      (startLine != filterStartLine or startColumn <= filterStartColumn) and
+      endLine >= filterEndLine and
+      (endLine != filterEndLine or endColumn >= filterEndColumn)
+    )
+  }
 }