Rule 17.2: Address performance/corretness issues

Simplify the query to only refer to one function call, which improves
performance and addresses a correctness issue when a function calls a
recursive function.

Author: lcartey

c/misra/src/rules/RULE-17-2/RecursiveFunctionCondition.ql

@@ -14,14 +14,12 @@
 import cpp
 import codingstandards.c.misra
 
-from FunctionCall call, string msg, FunctionCall fc
+from FunctionCall fc, Function f, string msg
 where
   not isExcluded(fc, Statements3Package::recursiveFunctionConditionQuery()) and
-  fc.getTarget() = call.getTarget() and
-  call.getTarget().calls*(call.getEnclosingFunction()) and
-  if fc.getTarget() = fc.getEnclosingFunction()
+  fc.getEnclosingFunction() = f and
+  fc.getTarget().calls*(f) and
+  if fc.getTarget() = f
   then msg = "This call directly invokes its containing function $@."
-  else
-    msg =
-      "The function " + fc.getEnclosingFunction() + " is indirectly recursive via this call to $@."
+  else msg = "The function " + f + " is indirectly recursive via this call to $@."
 select fc, msg, fc.getTarget(), fc.getTarget().getName()

c/misra/test/rules/RULE-17-2/RecursiveFunctionCondition.expected

@@ -1,4 +1,3 @@
 | test.c:8:3:8:4 | call to f3 | This call directly invokes its containing function $@. | test.c:7:6:7:7 | f3 | f3 |
-| test.c:11:3:11:4 | call to f3 | The function f6 is indirectly recursive via this call to $@. | test.c:7:6:7:7 | f3 | f3 |
 | test.c:15:3:15:4 | call to f2 | The function f5 is indirectly recursive via this call to $@. | test.c:17:6:17:7 | f2 | f2 |
 | test.c:18:3:18:4 | call to f5 | The function f2 is indirectly recursive via this call to $@. | test.c:14:6:14:7 | f5 | f5 |