[Expression Propagation] remove propagation limit (#348)

* Create draft PR for #44 * removed configurations and corresponding function * removed corresponding tests * Fix removed stages * Removed limit options * Fix stage order * Fix resolving conflict mistake --------- Co-authored-by: fnhartmann <[email protected]> Co-authored-by: fnhartmann <[email protected]> Co-authored-by: fnhartmann <[email protected]>
fkie-cad · Dec 6, 2023 · 2f0294a · 2f0294a
1 parent fcb7292
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diff --git a/decompiler/pipeline/commons/expressionpropagationcommons.py b/decompiler/pipeline/commons/expressionpropagationcommons.py
@@ -30,8 +30,6 @@ class ExpressionPropagationBase(PipelineStage, ABC):
     name = "expression-propagation-base"
 
     def __init__(self):
-        self._limit: Optional[int] = None
-        self._limits: Dict[Instruction, int]
         self._use_map: UseMap
         self._def_map: DefMap
         self._pointers_info: Optional[Pointers] = None
@@ -43,7 +41,6 @@ def __init__(self):
 
     def run(self, task: DecompilerTask):
         """Execute the expression propagation on the current ControlFlowGraph."""
-        self._parse_options(task)
         iteration = 0
         # execute until there are no more changes
         while self.perform(task.graph, iteration):
@@ -89,15 +86,6 @@ def _definition_can_be_propagated_into_target(self, definition: Assignment, targ
         """
         pass
 
-    def _parse_options(self, task: DecompilerTask):
-        """Parse the config options for this pipeline stage."""
-        self._limit = task.options.getint(f"{self.name}.maximum_instruction_complexity")
-        self._limits = {
-            Branch: min(self._limit, task.options.getint(f"{self.name}.maximum_branch_complexity")),
-            Call: min(self._limit, task.options.getint(f"{self.name}.maximum_call_complexity")),
-            Assignment: min(self._limit, task.options.getint(f"{self.name}.maximum_assignment_complexity")),
-        }
-
     def _initialize_maps(self, cfg: ControlFlowGraph) -> None:
         """
         Fills use and def maps.
@@ -205,22 +193,6 @@ def _operation_is_propagated_in_phi(self, target: Instruction, definition: Assig
         do not allow phi arguments to be unary or binary operations"""
         return isinstance(target, Phi) and isinstance(definition.value, Operation)
 
-    def _resulting_instruction_is_too_long(self, target: Instruction, definition: Assignment) -> bool:
-        """Instruction after expression propagation should not be longer than a given limit
-
-        we already test that only vars and constants are propagated in phi,
-        therefore the length of phi after propagation will be constant;
-        same with propagating instructions like e.g. a = b or a = 10.
-        """
-        if self._is_phi(target) or self._is_copy_assignment(definition):
-            return False
-        limit = self._limits.get(type(target), self._limit)
-        if self._is_call_assignment(target):
-            limit = self._limits[Call]
-        count = len([expr for expr in self._find_subexpressions(target) if expr == definition.destination])
-        propagated_complexity = target.complexity + (definition.value.complexity - definition.destination.complexity) * count
-        return propagated_complexity > limit
-
     def _is_address_assignment(self, definition: Assignment) -> bool:
         """
         Currently propagating a = &x into uses of a causes problems (see test21 in test_memory). So for the moment is not propagated.

diff --git a/decompiler/pipeline/dataflowanalysis/expressionpropagation.py b/decompiler/pipeline/dataflowanalysis/expressionpropagation.py
@@ -33,7 +33,6 @@ def _definition_can_be_propagated_into_target(self, definition: Assignment, targ
             or self._is_address_assignment(definition)
             or self._contains_global_variable(definition)
             or self._operation_is_propagated_in_phi(target, definition)
-            or self._resulting_instruction_is_too_long(target, definition)
             or self._is_invalid_propagation_into_address_operation(target, definition)
             or self._is_dereference_assignment(definition)
         )
diff --git a/decompiler/pipeline/dataflowanalysis/expressionpropagationfunctioncall.py b/decompiler/pipeline/dataflowanalysis/expressionpropagationfunctioncall.py
@@ -107,7 +107,6 @@ def _definition_can_be_propagated_into_target(self, definition: Assignment, targ
                 or self._is_address_assignment(definition)
                 or self._contains_global_variable(definition)
                 or self._operation_is_propagated_in_phi(target, definition)
-                or self._resulting_instruction_is_too_long(target, definition)
                 or self._is_invalid_propagation_into_address_operation(target, definition)
                 or self._is_dereference_assignment(definition)
                 or self._definition_value_could_be_modified_via_memory_access_between_definition_and_target(definition, target)

diff --git a/decompiler/pipeline/dataflowanalysis/expressionpropagationmemory.py b/decompiler/pipeline/dataflowanalysis/expressionpropagationmemory.py
@@ -54,7 +54,6 @@ def _definition_can_be_propagated_into_target(self, definition: Assignment, targ
             or self._contains_global_variable(definition)
             or self._operation_is_propagated_in_phi(target, definition)
             or self._is_invalid_propagation_into_address_operation(target, definition)
-            or self._resulting_instruction_is_too_long(target, definition)
             or self._is_aliased_postponed_for_propagation(target, definition)
             or self._definition_value_could_be_modified_via_memory_access_between_definition_and_target(definition, target)
             or self._pointer_value_used_in_definition_could_be_modified_via_memory_access_between_definition_and_target(definition, target)

diff --git a/decompiler/util/default.json b/decompiler/util/default.json
@@ -1,130 +1,4 @@
 [
-    {
-        "title": "Expression Propagation",
-        "description": "Settings for the expression propagation pipeline stages:",
-        "options": [
-            {
-                "dest": "expression-propagation.maximum_instruction_complexity",
-                "default": 100,
-                "title": "EP maximum instruction complexity",
-                "type": "number",
-                "description": "Maximum complexity for an instruction to be propagated",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--ep-max-instruction-complexity"
-            },
-            {
-                "dest": "expression-propagation.maximum_branch_complexity",
-                "default": 100,
-                "title": "EP maximum branch complexity",
-                "type": "number",
-                "description": "Maximum complexity for a branch to be propagated",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--ep-max-branch-complexity"
-            },
-            {
-                "dest": "expression-propagation.maximum_call_complexity",
-                "default": 100,
-                "title": "EP maximum call complexity",
-                "type": "number",
-                "description": "Maximum complexity for a call to be propagated",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--ep-max-call-complexity"
-            },
-            {
-                "dest": "expression-propagation.maximum_assignment_complexity",
-                "default": 100,
-                "title": "EP maximum assignment complexity",
-                "type": "number",
-                "description": "Maximum complexity for an assignment to be propagated",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--ep-max-assignment-complexity"
-            },
-            {
-                "dest": "expression-propagation-memory.maximum_instruction_complexity",
-                "default": 100,
-                "title": "EPM maximum instruction complexity",
-                "type": "number",
-                "description": "Maximum complexity for an instruction to be propagated (consider memory access)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epm-max-instruction-complexity"
-            },
-            {
-                "dest": "expression-propagation-memory.maximum_branch_complexity",
-                "default": 100,
-                "title": "EPM maximum branch complexity",
-                "type": "number",
-                "description": "Maximum complexity for a branch to be propagated (consider memory access)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epm-max-branch-complexity"
-            },
-            {
-                "dest": "expression-propagation-memory.maximum_call_complexity",
-                "default": 100,
-                "title": "EPM maximum call complexity",
-                "type": "number",
-                "description": "Maximum complexity for a call to be propagated (consider memory access)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epm-max-call-complexity"
-            },
-            {
-                "dest": "expression-propagation-memory.maximum_assignment_complexity",
-                "default": 100,
-                "title": "EPM maximum assignment complexity",
-                "type": "number",
-                "description": "Maximum complexity for an assignment to be propagated (consider memory access)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epm-max-assignment-complexity"
-            },
-            {
-                "dest": "expression-propagation-function-call.maximum_instruction_complexity",
-                "default": 100,
-                "title": "EPFC maximum instruction complexity",
-                "type": "number",
-                "description": "Maximum complexity for an instruction to be propagated (consider function calls)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epfc-max-instruction-complexity"
-            },
-            {
-                "dest": "expression-propagation-function-call.maximum_branch_complexity",
-                "default": 100,
-                "title": "EPFC maximum branch complexity",
-                "type": "number",
-                "description": "Maximum complexity for a branch to be propagated (consider function calls)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epfc-max-branch-complexity"
-            },
-            {
-                "dest": "expression-propagation-function-call.maximum_call_complexity",
-                "default": 100,
-                "title": "EPFC maximum call complexity",
-                "type": "number",
-                "description": "Maximum complexity for a call to be propagated (consider function calls)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epfc-max-call-complexity"
-            },
-            {
-                "dest": "expression-propagation-function-call.maximum_assignment_complexity",
-                "default": 100,
-                "title": "EPFC maximum assignment complexity",
-                "type": "number",
-                "description": "Maximum complexity for an assignment to be propagated (consider function calls)",
-                "is_hidden_from_gui": true,
-                "is_hidden_from_cli": false,
-                "argument_name": "--epfc-max-assignment-complexity"
-            }
-        ]
-    },
     {
         "title": "Code Elimination",
         "description": "Dead code, and common subexpression elimination settings:",