A5-1-9: Address param confusion

The hash cons value for parameters was incorrectly calculated with
parameter uses (e.g accesses to the parameter). The correct
approach is to use the variable name and type.

This caused performance issues, because the hash cons for a
function was made up of all combinations of the accesses to the
parameters. For lambdas with many parameters and many accesses,
this was problematic.

Author: lcartey

cpp/autosar/src/rules/A5-1-9/LambdaEquivalence.qll

@@ -211,7 +211,7 @@ private module HashCons {
 
   private newtype HC_Params =
     HC_NoParams() or
-    HC_ParamCons(HashConsExpr hc, int i, HC_Params list) { mk_ParamCons(hc, i, list, _) }
+    HC_ParamCons(Type t, string name, int i, HC_Params list) { mk_ParamCons(t, name, i, list, _) }
 
   /**
    * HashConsExpr is the hash-cons of an expression. The relationship between `Expr`
@@ -1275,24 +1275,25 @@ private module HashCons {
     mk_DeclConsInner(_, _, s.getNumDeclarations() - 1, hc, s)
   }
 
-  private predicate mk_ParamCons(HashConsExpr hc, int i, HC_Params list, Function f) {
-    hc = hashConsExpr(f.getParameter(i).getAnAccess()) and
-    (
-      exists(HashConsExpr head, HC_Params tail |
-        mk_ParamConsInner(head, tail, i - 1, list, f) and
-        i > 0
-      )
+  private predicate mk_ParamCons(Type t, string name, int i, HC_Params list, Function f) {
+    exists(Parameter p |
+      p = f.getParameter(i) and
+      t = p.getType() and
+      name = p.getName()
+    |
+      mk_ParamConsInner(_, _, _, i - 1, list, f) and
+      i > 0
       or
       i = 0 and
       list = HC_NoParams()
     )
   }
 
   private predicate mk_ParamConsInner(
-    HashConsExpr head, HC_Params tail, int i, HC_Params list, Function f
+    Type t, string name, HC_Params tail, int i, HC_Params list, Function f
   ) {
-    list = HC_ParamCons(head, i, tail) and
-    mk_ParamCons(head, i, tail, f)
+    list = HC_ParamCons(t, name, i, tail) and
+    mk_ParamCons(t, name, i, tail, f)
   }
 
   private predicate mk_FunctionCons(
@@ -1302,7 +1303,7 @@ private module HashCons {
     name = f.getName() and
     body = hashConsStmt(f.getBlock()) and
     if f.getNumberOfParameters() > 0
-    then mk_ParamConsInner(_, _, f.getNumberOfParameters() - 1, params, f)
+    then mk_ParamConsInner(_, _, _, f.getNumberOfParameters() - 1, params, f)
     else params = HC_NoParams()
   }