Start `slither.utils.upgradeability`

slither/utils/upgradeability.py

@@ -0,0 +1,32 @@
+from slither.core.declarations.contract import Contract
+
+
+def compare(v1: Contract, v2: Contract):
+    order_vars1 = [v for v in v1.state_variables if not v.is_constant and not v.is_immutable]
+    order_vars2 = [v for v in v2.state_variables if not v.is_constant and not v.is_immutable]
+    func_sigs1 = [function.solidity_signature for function in v1.functions]
+    func_sigs2 = [function.solidity_signature for function in v2.functions]
+
+    results = {
+        "missing-vars-in-v2": [],
+        "new-variables": [],
+        "tainted-variables": [],
+        "new-functions": [],
+        "modified-functions": [],
+        "tainted-functions": []
+    }
+
+    if len(order_vars2) <= len(order_vars1):
+        for variable in order_vars1:
+            if variable.name not in [v.name for v in order_vars2]:
+                results["missing-vars-in-v2"].append(variable)
+
+    new_modified_functions = []
+    for sig in func_sigs2:
+        function = v2.get_function_from_signature(sig)
+        if sig not in func_sigs1:
+            new_modified_functions.append(function)
+            results["new-functions"].append(function)
+        else:
+            orig_function = v1.get_function_from_signature(sig)
+            if function