C++: Add cpp/extraction-information query

cpp/ql/src/Telemetry/DatabaseQuality.qll

@@ -0,0 +1,25 @@
+import cpp
+import codeql.util.ReportStats
+
+module CallTargetStats implements StatsSig {
+  private class RelevantCall extends Call {
+    RelevantCall() { this.getFile() = any(File f | f.fromSource() and exists(f.getRelativePath())) }
+  }
+
+  // We assume that calls with an implicit target are calls that could not be
+  // resolved. This is accurate in the vast amount of cases, but is inaccurate
+  // for calls that deliberately rely on implicitly declared functions.
+  private predicate hasImplicitTarget(RelevantCall call) {
+    call.getTarget().getADeclarationEntry().isImplicit()
+  }
+
+  int getNumberOfOk() { result = count(RelevantCall call | not hasImplicitTarget(call)) }
+
+  int getNumberOfNotOk() { result = count(RelevantCall call | hasImplicitTarget(call)) }
+
+  string getOkText() { result = "calls with call target" }
+
+  string getNotOkText() { result = "calls with missing call target" }
+}
+
+module CallTargetStatsReport = ReportStats<CallTargetStats>;