RULE-11-4: Compress macro results

Where results arise from macro expansions, where there's no possibility
that the cast was passed in through a macro argument, we compress the
results by reporting the macro location once instead of each use.

Author: lcartey

c/misra/src/rules/RULE-11-4/ConversionBetweenPointerToObjectAndIntegerType.ql

@@ -13,15 +13,34 @@
 
 import cpp
 import codingstandards.c.misra
+import codingstandards.cpp.Macro
 import codingstandards.c.Pointers
 
-from CStyleCast cast, Type typeFrom, Type typeTo
+MacroInvocation getAMacroInvocation(CStyleCast cast) { result.getAnExpandedElement() = cast }
+
+Macro getPrimaryMacro(CStyleCast cast) {
+  exists(MacroInvocation mi |
+    mi = getAMacroInvocation(cast) and
+    not exists(MacroInvocation otherMi |
+      otherMi = getAMacroInvocation(cast) and otherMi.getParentInvocation() = mi
+    ) and
+    result = mi.getMacro() and
+    not result instanceof FunctionLikeMacro
+  )
+}
+
+from Locatable primaryLocation, CStyleCast cast, Type typeFrom, Type typeTo
 where
   not isExcluded(cast, Pointers1Package::castBetweenObjectPointerAndDifferentObjectTypeQuery()) and
   typeFrom = cast.getExpr().getUnderlyingType() and
   typeTo = cast.getUnderlyingType() and
   [typeFrom, typeTo] instanceof IntegralType and
   [typeFrom, typeTo] instanceof PointerToObjectType and
-  not isNullPointerConstant(cast.getExpr())
-select cast,
+  not isNullPointerConstant(cast.getExpr()) and
+  // If this alert is arising through a macro expansion, flag the macro instead, to
+  // help make the alerts more manageable
+  if exists(getPrimaryMacro(cast))
+  then primaryLocation = getPrimaryMacro(cast)
+  else primaryLocation = cast
+select primaryLocation,
   "Cast performed between a pointer to object type and a pointer to an integer type."