Add compiler improvement

Project-02-03-04-05/optimizations/DeadAssignmentElimination.py

@@ -0,0 +1,46 @@
+from __future__ import annotations
+
+import cfg_build
+from cfg.CFG import CFG
+from cfg.CFG_Node import CFG_Node
+from cfa.ReachedUses import ReachedUses
+from syntax import EXPRESSION, ASSIGN
+from optimizations.Optimization import Optimization
+
+class DeadAssignmentElimination(Optimization):
+    def __init__(self) -> None:
+        self._node_by_ast_id: dict[int, CFG_Node] = {}
+        self.__ru: ReachedUses | None = None
+
+    def setup(self, ast: EXPRESSION) -> None:
+        cfg_build.FUNCTIONS.clear()
+        cfg_build.CURRENT_FUNCTION = None
+        cfg = CFG(ast)
+        self.__ru = ReachedUses(cfg)
+        self._node_by_ast_id = {id(n.ast_node): n for n in self.__ru.cfg.nodes() if n.ast_node is not None}
+
+    def apply(self, node: EXPRESSION) -> EXPRESSION:
+        # Only ASSIGN nodes can be dead assignments.
+        if not isinstance(node, ASSIGN):
+            return node
+
+        # Find the CFG node corresponding to this AST node.
+        # If none is found, the node was not analyzed — leave it unchanged.
+        cfg_node = self._node_by_ast_id.get(id(node))
+        if cfg_node is None:
+            return node
+
+        ru = self.__ru
+        nid = cfg_node.id
+        defined_vars = ru.defs.get(nid, set())
+        out = ru.out_sets.get(nid, set())
+
+        # Check if any use-fact in OUT(n) belongs to a variable defined at n.
+        # If so, the assignment is live — at least one use is reachable from here.
+        for (_, var) in out:
+            if var in defined_vars:
+                return node
+
+        # No reached use found for the assigned variable — the assignment is dead.
+        # Replace ASSIGN(var, expr) with expr to preserve side effects on the RHS.
+        return node.expr

Project-02-03-04-05/optimizations/Optimization.py

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+from __future__ import annotations
+from syntax import EXPRESSION
+
+
+class Optimization:
+    def setup(self, ast: EXPRESSION) -> None: ...
+    def apply(self, node: EXPRESSION) -> EXPRESSION: ...

Project-02-03-04-05/optimizations/__init__.py

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+from optimizations.DeadAssignmentElimination import DeadAssignmentElimination
+from optimizations.Optimization import Optimization

Project-02-03-04-05/optimizations/optimize.py

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+from __future__ import annotations
+from optimizations.Optimization import Optimization
+from optimizations.DeadAssignmentElimination import DeadAssignmentElimination
+from syntax import EXPRESSION
+
+# Traverses the AST and applies the given optimizations
+def __apply_optimizations(node: EXPRESSION, optimizations: list[Optimization]) -> EXPRESSION:
+    for key, value in list(node.__dict__.items()):
+        if key == "pp":
+            continue
+        if isinstance(value, EXPRESSION):
+            new_child = __apply_optimizations(value, optimizations)
+            if new_child is not value:
+                setattr(node, key, new_child)
+        elif isinstance(value, list):
+            for i, elem in enumerate(value):
+                if isinstance(elem, EXPRESSION):
+                    new_elem = __apply_optimizations(elem, optimizations)
+                    if new_elem is not elem:
+                        value[i] = new_elem
+
+    result: EXPRESSION = node
+    for opt in optimizations:
+        result = opt.apply(result)
+    return result
+
+# Stores the active optimizations
+ACTIVE_OPTIMIZATIONS: list[Optimization] = [
+    DeadAssignmentElimination(),
+]
+
+# Apply optimizations to the given AST node
+def optimize(ast: EXPRESSION) -> EXPRESSION:
+    for opt in ACTIVE_OPTIMIZATIONS:
+        opt.setup(ast)
+    return __apply_optimizations(ast, ACTIVE_OPTIMIZATIONS)