Merge pull request #2588 from crytic/dev-support-transient

Improve transient storage support

slither/core/compilation_unit.py

@@ -73,7 +73,8 @@ def __init__(self, core: "SlitherCore", crytic_compilation_unit: CompilationUnit
         # Memoize
         self._all_state_variables: Optional[Set[StateVariable]] = None
 
-        self._storage_layouts: Dict[str, Dict[str, Tuple[int, int]]] = {}
+        self._persistent_storage_layouts: Dict[str, Dict[str, Tuple[int, int]]] = {}
+        self._transient_storage_layouts: Dict[str, Dict[str, Tuple[int, int]]] = {}
 
         self._contract_with_missing_inheritance: Set[Contract] = set()
 
@@ -297,33 +298,52 @@ def get_scope(self, filename_str: str) -> FileScope:
 
     def compute_storage_layout(self) -> None:
         assert self.is_solidity
+
         for contract in self.contracts_derived:
-            self._storage_layouts[contract.name] = {}
-
-            slot = 0
-            offset = 0
-            for var in contract.stored_state_variables_ordered:
-                assert var.type
-                size, new_slot = var.type.storage_size
-
-                if new_slot:
-                    if offset > 0:
-                        slot += 1
-                        offset = 0
-                elif size + offset > 32:
+            self._compute_storage_layout(contract.name, contract.storage_variables_ordered, False)
+            self._compute_storage_layout(contract.name, contract.transient_variables_ordered, True)
+
+    def _compute_storage_layout(
+        self, contract_name: str, state_variables_ordered: List[StateVariable], is_transient: bool
+    ):
+        if is_transient:
+            self._transient_storage_layouts[contract_name] = {}
+        else:
+            self._persistent_storage_layouts[contract_name] = {}
+
+        slot = 0
+        offset = 0
+        for var in state_variables_ordered:
+            assert var.type
+            size, new_slot = var.type.storage_size
+
+            if new_slot:
+                if offset > 0:
                     slot += 1
                     offset = 0
+            elif size + offset > 32:
+                slot += 1
+                offset = 0
 
-                self._storage_layouts[contract.name][var.canonical_name] = (
+            if is_transient:
+                self._transient_storage_layouts[contract_name][var.canonical_name] = (
                     slot,
                     offset,
                 )
-                if new_slot:
-                    slot += math.ceil(size / 32)
-                else:
-                    offset += size
+            else:
+                self._persistent_storage_layouts[contract_name][var.canonical_name] = (
+                    slot,
+                    offset,
+                )
+
+            if new_slot:
+                slot += math.ceil(size / 32)
+            else:
+                offset += size
 
     def storage_layout_of(self, contract: Contract, var: StateVariable) -> Tuple[int, int]:
-        return self._storage_layouts[contract.name][var.canonical_name]
+        if var.is_stored:
+            return self._persistent_storage_layouts[contract.name][var.canonical_name]
+        return self._transient_storage_layouts[contract.name][var.canonical_name]
 
     # endregion

slither/core/declarations/contract.py

@@ -440,55 +440,43 @@ def variables_as_dict(self) -> Dict[str, "StateVariable"]:
     def state_variables(self) -> List["StateVariable"]:
         """
         Returns all the accessible variables (do not include private variable from inherited contract).
-        Use state_variables_ordered for all the variables following the storage order
+        Use stored_state_variables_ordered for all the storage variables following the storage order
+        Use transient_state_variables_ordered for all the transient variables following the storage order
 
         list(StateVariable): List of the state variables.
         """
         return list(self._variables.values())
 
     @property
-    def stored_state_variables(self) -> List["StateVariable"]:
+    def state_variables_entry_points(self) -> List["StateVariable"]:
         """
-        Returns state variables with storage locations, excluding private variables from inherited contracts.
-        Use stored_state_variables_ordered to access variables with storage locations in their declaration order.
-
-        This implementation filters out state variables if they are constant or immutable. It will be
-        updated to accommodate any new non-storage keywords that might replace 'constant' and 'immutable' in the future.
-
-        Returns:
-            List[StateVariable]: A list of state variables with storage locations.
+        list(StateVariable): List of the state variables that are public.
         """
-        return [variable for variable in self.state_variables if variable.is_stored]
+        return [var for var in self._variables.values() if var.visibility == "public"]
 
     @property
-    def stored_state_variables_ordered(self) -> List["StateVariable"]:
+    def state_variables_ordered(self) -> List["StateVariable"]:
         """
-        list(StateVariable): List of the state variables with storage locations by order of declaration.
-
-        This implementation filters out state variables if they are constant or immutable. It will be
-        updated to accommodate any new non-storage keywords that might replace 'constant' and 'immutable' in the future.
-
-        Returns:
-            List[StateVariable]: A list of state variables with storage locations ordered by declaration.
+        list(StateVariable): List of the state variables by order of declaration.
         """
-        return [variable for variable in self.state_variables_ordered if variable.is_stored]
+        return self._variables_ordered
+
+    def add_state_variables_ordered(self, new_vars: List["StateVariable"]) -> None:
+        self._variables_ordered += new_vars
 
     @property
-    def state_variables_entry_points(self) -> List["StateVariable"]:
+    def storage_variables_ordered(self) -> List["StateVariable"]:
         """
-        list(StateVariable): List of the state variables that are public.
+        list(StateVariable): List of the state variables in storage location by order of declaration.
         """
-        return [var for var in self._variables.values() if var.visibility == "public"]
+        return [v for v in self._variables_ordered if v.is_stored]
 
     @property
-    def state_variables_ordered(self) -> List["StateVariable"]:
+    def transient_variables_ordered(self) -> List["StateVariable"]:
         """
-        list(StateVariable): List of the state variables by order of declaration.
+        list(StateVariable): List of the state variables in transient location by order of declaration.
         """
-        return list(self._variables_ordered)
-
-    def add_variables_ordered(self, new_vars: List["StateVariable"]) -> None:
-        self._variables_ordered += new_vars
+        return [v for v in self._variables_ordered if v.is_transient]
 
     @property
     def state_variables_inherited(self) -> List["StateVariable"]:

slither/core/variables/state_variable.py

@@ -35,6 +35,22 @@ def location(self) -> Optional[str]:
         """
         return self._location
 
+    @property
+    def is_stored(self) -> bool:
+        """
+        Checks if the state variable is stored, based on it not being constant or immutable or transient.
+        """
+        return (
+            not self._is_constant and not self._is_immutable and not self._location == "transient"
+        )
+
+    @property
+    def is_transient(self) -> bool:
+        """
+        Checks if the state variable is transient. A transient variable can not be constant or immutable.
+        """
+        return self._location == "transient"
+
     # endregion
     ###################################################################################
     ###################################################################################

slither/core/variables/variable.py

@@ -93,13 +93,6 @@ def is_constant(self) -> bool:
     def is_constant(self, is_cst: bool) -> None:
         self._is_constant = is_cst
 
-    @property
-    def is_stored(self) -> bool:
-        """
-        Checks if a variable is stored, based on it not being constant or immutable. Future updates may adjust for new non-storage keywords.
-        """
-        return not self._is_constant and not self._is_immutable
-
     @property
     def is_reentrant(self) -> bool:
         return self._is_reentrant

slither/detectors/variables/unchanged_state_variables.py

@@ -92,7 +92,7 @@ def detect(self) -> None:
             variables = []
             functions = []
 
-            variables.append(c.stored_state_variables)
+            variables.append(c.storage_variables_ordered)
             functions.append(c.all_functions_called)
 
             valid_candidates: Set[StateVariable] = {

slither/printers/summary/variable_order.py

@@ -27,10 +27,17 @@ def output(self, _filename: str) -> Output:
 
         for contract in self.slither.contracts_derived:
             txt += f"\n{contract.name}:\n"
-            table = MyPrettyTable(["Name", "Type", "Slot", "Offset"])
-            for variable in contract.stored_state_variables_ordered:
+            table = MyPrettyTable(["Name", "Type", "Slot", "Offset", "State"])
+            for variable in contract.storage_variables_ordered:
                 slot, offset = contract.compilation_unit.storage_layout_of(contract, variable)
-                table.add_row([variable.canonical_name, str(variable.type), slot, offset])
+                table.add_row(
+                    [variable.canonical_name, str(variable.type), slot, offset, "Storage"]
+                )
+            for variable in contract.transient_variables_ordered:
+                slot, offset = contract.compilation_unit.storage_layout_of(contract, variable)
+                table.add_row(
+                    [variable.canonical_name, str(variable.type), slot, offset, "Transient"]
+                )
 
             all_tables.append((contract.name, table))
             txt += str(table) + "\n"

slither/solc_parsing/declarations/contract.py

@@ -350,7 +350,7 @@ def parse_state_variables(self) -> None:
                     if v.visibility != "private"
                 }
             )
-            self._contract.add_variables_ordered(
+            self._contract.add_state_variables_ordered(
                 [
                     var
                     for var in father.state_variables_ordered
@@ -370,7 +370,7 @@ def parse_state_variables(self) -> None:
             if var_parser.reference_id is not None:
                 self._contract.state_variables_by_ref_id[var_parser.reference_id] = var
             self._contract.variables_as_dict[var.name] = var
-            self._contract.add_variables_ordered([var])
+            self._contract.add_state_variables_ordered([var])
 
     def _parse_modifier(self, modifier_data: Dict) -> None:
         modif = Modifier(self._contract.compilation_unit)

slither/tools/upgradeability/checks/variable_initialization.py

@@ -43,7 +43,7 @@ class VariableWithInit(AbstractCheck):
 
     def _check(self) -> List[Output]:
         results = []
-        for s in self.contract.stored_state_variables_ordered:
+        for s in self.contract.storage_variables_ordered:
             if s.initialized:
                 info: CHECK_INFO = [s, " is a state variable with an initial value.\n"]
                 json = self.generate_result(info)

slither/tools/upgradeability/checks/variables_order.py

@@ -115,29 +115,43 @@ def _contract2(self) -> Contract:
     def _check(self) -> List[Output]:
         contract1 = self._contract1()
         contract2 = self._contract2()
-        order1 = contract1.stored_state_variables_ordered
-        order2 = contract2.stored_state_variables_ordered
 
         results: List[Output] = []
-        for idx, _ in enumerate(order1):
-            if len(order2) <= idx:
-                # Handle by MissingVariable
-                return results
-
-            variable1 = order1[idx]
-            variable2 = order2[idx]
-            if (variable1.name != variable2.name) or (variable1.type != variable2.type):
-                info: CHECK_INFO = [
-                    "Different variables between ",
-                    contract1,
-                    " and ",
-                    contract2,
-                    "\n",
-                ]
-                info += ["\t ", variable1, "\n"]
-                info += ["\t ", variable2, "\n"]
-                json = self.generate_result(info)
-                results.append(json)
+
+        def _check_internal(
+            contract1: Contract, contract2: Contract, results: List[Output], is_transient: bool
+        ):
+            if is_transient:
+                order1 = contract1.transient_variables_ordered
+                order2 = contract2.transient_variables_ordered
+            else:
+                order1 = contract1.storage_variables_ordered
+                order2 = contract2.storage_variables_ordered
+
+            for idx, _ in enumerate(order1):
+                if len(order2) <= idx:
+                    # Handle by MissingVariable
+                    return
+
+                variable1 = order1[idx]
+                variable2 = order2[idx]
+                if (variable1.name != variable2.name) or (variable1.type != variable2.type):
+                    info: CHECK_INFO = [
+                        "Different variables between ",
+                        contract1,
+                        " and ",
+                        contract2,
+                        "\n",
+                    ]
+                    info += ["\t ", variable1, "\n"]
+                    info += ["\t ", variable2, "\n"]
+                    json = self.generate_result(info)
+                    results.append(json)
+
+        # Checking state variables with storage location
+        _check_internal(contract1, contract2, results, False)
+        # Checking state variables with transient location
+        _check_internal(contract1, contract2, results, True)
 
         return results
 
@@ -236,22 +250,35 @@ def _contract2(self) -> Contract:
     def _check(self) -> List[Output]:
         contract1 = self._contract1()
         contract2 = self._contract2()
-        order1 = contract1.stored_state_variables_ordered
-        order2 = contract2.stored_state_variables_ordered
 
-        results = []
+        results: List[Output] = []
 
-        if len(order2) <= len(order1):
-            return []
+        def _check_internal(
+            contract1: Contract, contract2: Contract, results: List[Output], is_transient: bool
+        ):
+            if is_transient:
+                order1 = contract1.transient_variables_ordered
+                order2 = contract2.transient_variables_ordered
+            else:
+                order1 = contract1.storage_variables_ordered
+                order2 = contract2.storage_variables_ordered
 
-        idx = len(order1)
+            if len(order2) <= len(order1):
+                return
 
-        while idx < len(order2):
-            variable2 = order2[idx]
-            info: CHECK_INFO = ["Extra variables in ", contract2, ": ", variable2, "\n"]
-            json = self.generate_result(info)
-            results.append(json)
-            idx = idx + 1
+            idx = len(order1)
+
+            while idx < len(order2):
+                variable2 = order2[idx]
+                info: CHECK_INFO = ["Extra variables in ", contract2, ": ", variable2, "\n"]
+                json = self.generate_result(info)
+                results.append(json)
+                idx = idx + 1
+
+        # Checking state variables with storage location
+        _check_internal(contract1, contract2, results, False)
+        # Checking state variables with transient location
+        _check_internal(contract1, contract2, results, True)
 
         return results
 

slither/utils/upgradeability.py

@@ -80,8 +80,8 @@ def compare(
         tainted-contracts: list[TaintedExternalContract]
     """
 
-    order_vars1 = v1.stored_state_variables_ordered
-    order_vars2 = v2.stored_state_variables_ordered
+    order_vars1 = v1.storage_variables_ordered + v1.transient_variables_ordered
+    order_vars2 = v2.storage_variables_ordered + v2.transient_variables_ordered
     func_sigs1 = [function.solidity_signature for function in v1.functions]
     func_sigs2 = [function.solidity_signature for function in v2.functions]
 
@@ -306,8 +306,8 @@ def get_missing_vars(v1: Contract, v2: Contract) -> List[StateVariable]:
         List of StateVariables from v1 missing in v2
     """
     results = []
-    order_vars1 = v1.stored_state_variables_ordered
-    order_vars2 = v2.stored_state_variables_ordered
+    order_vars1 = v1.storage_variables_ordered + v1.transient_variables_ordered
+    order_vars2 = v2.storage_variables_ordered + v2.transient_variables_ordered
     if len(order_vars2) < len(order_vars1):
         for variable in order_vars1:
             if variable.name not in [v.name for v in order_vars2]:

slither/vyper_parsing/declarations/contract.py

@@ -470,7 +470,7 @@ def parse_state_variables(self) -> None:
 
             assert var.name
             self._contract.variables_as_dict[var.name] = var
-            self._contract.add_variables_ordered([var])
+            self._contract.add_state_variables_ordered([var])
             # Interfaces can refer to constants
             self._contract.file_scope.variables[var.name] = var