Ruby: prune unusable summaries earlier

Author: asgerf

ruby/ql/lib/codeql/ruby/typetracking/TypeTrackerSpecific.qll

@@ -343,15 +343,19 @@ private predicate hasStoreSummary(
   SummarizedCallable callable, DataFlow::ContentSet contents, SummaryComponentStack input,
   SummaryComponentStack output
 ) {
-  callable.propagatesFlow(input, push(SummaryComponent::content(contents), output), true)
+  callable.propagatesFlow(input, push(SummaryComponent::content(contents), output), true) and
+  not isNonLocal(input.head()) and
+  not isNonLocal(output.head())
 }
 
 pragma[nomagic]
 private predicate hasLoadSummary(
   SummarizedCallable callable, DataFlow::ContentSet contents, SummaryComponentStack input,
   SummaryComponentStack output
 ) {
-  callable.propagatesFlow(push(SummaryComponent::content(contents), input), output, true)
+  callable.propagatesFlow(push(SummaryComponent::content(contents), input), output, true) and
+  not isNonLocal(input.head()) and
+  not isNonLocal(output.head())
 }
 
 pragma[nomagic]
@@ -362,6 +366,8 @@ private predicate hasLoadStoreSummary(
   callable
       .propagatesFlow(push(SummaryComponent::content(loadContents), input),
         push(SummaryComponent::content(storeContents), output), true) and
+  not isNonLocal(input.head()) and
+  not isNonLocal(output.head()) and
   callable != "Hash.[]" // Special-cased due to having a huge number of summaries
 }
 
@@ -397,6 +403,8 @@ private predicate hasWithoutContentSummary(
   exists(DataFlow::ContentSet content |
     callable.propagatesFlow(push(SummaryComponent::withoutContent(content), input), output, true) and
     filter = getFilterFromWithoutContentStep(content) and
+    not isNonLocal(input.head()) and
+    not isNonLocal(output.head()) and
     input != output
   )
 }
@@ -433,10 +441,18 @@ private predicate hasWithContentSummary(
   exists(DataFlow::ContentSet content |
     callable.propagatesFlow(push(SummaryComponent::withContent(content), input), output, true) and
     filter = getFilterFromWithContentStep(content) and
+    not isNonLocal(input.head()) and
+    not isNonLocal(output.head()) and
     input != output
   )
 }
 
+/**
+ * Holds if the given component can't be evaluated by `evaluateSummaryComponentStackLocal`.
+ */
+pragma[nomagic]
+predicate isNonLocal(SummaryComponent component) { component = SC::content(_) }
+
 /**
  * Gets a data flow node corresponding an argument or return value of `call`,
  * as specified by `component`.