First working solution of new task

2026-03-05 18:03:55 +01:00
parent 691d6eba8c
commit de46c67129
11 changed files with 1077 additions and 9 deletions
--- a/Project-02-03-04-05/Source.gv.png
+++ b/Project-02-03-04-05/Source.gv.png
--- a/Project-02-03-04-05/cfa/init.py
+++ b/Project-02-03-04-05/cfa/init.py
@@ -0,0 +1,9 @@
+from .live_variables import LiveVariablesAnalysis, Var
+from .reached_uses import ReachedUsesAnalysis, UseFact
+
+__all__ = [
+    "Var",
+    "UseFact",
+    "LiveVariablesAnalysis",
+    "ReachedUsesAnalysis",
+]
--- a/Project-02-03-04-05/cfa/analysis_dot.py
+++ b/Project-02-03-04-05/cfa/analysis_dot.py
@@ -0,0 +1,192 @@
+import syntax
+import colorsys
+from cfg.CFG_Node import CFG_DIAMOND
+
+
+def _expr_used_names(expr) -> set[str]:
+    """Collect variable names (syntax.ID) used inside an expression subtree."""
+    used: set[str] = set()
+
+    def visit(node):
+        if node is None:
+            return
+        if isinstance(node, syntax.ID):
+            used.add(node.name)
+            return
+        if isinstance(node, syntax.EXPRESSION):
+            for _, child in node.children():
+                visit(child)
+
+    visit(expr)
+    return used
+
+
+def _show_analysis_on_node(node) -> bool:
+    """Return True if analysis annotations should be displayed for this node."""
+    ast = node.ast_node
+    if isinstance(node, CFG_DIAMOND):
+        return False
+    if ast is None:
+        return False
+    return isinstance(
+        ast,
+        (
+            syntax.ASSIGN,
+            syntax.CALL,
+            syntax.IF,
+            syntax.WHILE,
+            syntax.DECL,
+            syntax.LET,
+            syntax.SEQ,
+            syntax.COMP,
+            syntax.EQOP,
+            syntax.LOP,
+        ),
+    )
+
+
+def _lv_in_for_display(node, analysis):
+    """Display-level IN set for LV."""
+    in_set = set(analysis.in_sets.get(node.id, set()))
+    ast_node = node.ast_node
+    if isinstance(ast_node, syntax.ASSIGN):
+        func = analysis._func_scope.get(node.id)
+        rhs_vars = {
+            analysis._resolve_var(func, name)
+            for name in _expr_used_names(ast_node.expr)
+        }
+        in_set |= rhs_vars
+    return in_set
+
+
+def _node_color(node_id: int) -> tuple[str, str]:
+    """Return (edge_color, fill_color) deterministically for a node id."""
+    # Golden-angle hue distribution gives stable, distinct colors.
+    hue = ((node_id * 0.6180339887498949) % 1.0)
+    edge_rgb = colorsys.hsv_to_rgb(hue, 0.70, 0.82)
+    fill_rgb = colorsys.hsv_to_rgb(hue, 0.28, 0.97)
+
+    def to_hex(rgb):
+        r, g, b = (int(round(c * 255)) for c in rgb)
+        return f"#{r:02x}{g:02x}{b:02x}"
+
+    return to_hex(edge_rgb), to_hex(fill_rgb)
+
+
+def run_all_analyses(cfg):
+    """Run Live Variables and Reached Uses on *cfg*.
+
+    Returns ``(analyses, annotations, ru_edges)`` where:
+      • *analyses* is a dict with keys ``"lv"`` and ``"ru"``,
+      • *annotations* contains only LivingVariables helper-node labels,
+      • *ru_edges* maps definition-node ids to reached use-node ids.
+    """
+    node_by_id = {n.id: n for n in cfg.nodes()}
+
+    from cfa.live_variables import LiveVariablesAnalysis
+    from cfa.reached_uses import ReachedUsesAnalysis
+
+    lv = LiveVariablesAnalysis(cfg)
+    ru = ReachedUsesAnalysis(cfg)
+
+    all_ids = set(lv.in_sets.keys()) | set(lv.out_sets.keys())
+    annotations = {
+        nid: (
+            "LivingVariables\\n"
+            f"In := {sorted(_lv_in_for_display(node_by_id[nid], lv))}\\n"
+            f"Out := {sorted(lv.out_sets.get(nid, set()))}"
+        )
+        for nid in all_ids
+        if lv.in_sets.get(nid, set()) or lv.out_sets.get(nid, set())
+        if nid in node_by_id and _show_analysis_on_node(node_by_id[nid])
+    }
+
+    return {"lv": lv, "ru": ru}, annotations, ru.reached_uses_by_node()
+
+
+def analysis_to_dot(
+    cfg,
+    annotations: dict[int, str],
+    analysis_name: str,
+    ru_edges: dict[int, list[int]] | None = None,
+) -> str:
+    """Return a DOT string for *cfg* annotated with analysis results."""
+    lines = [
+        "digraph CFG {",
+        f'  // Analysis: {analysis_name}',
+        '  graph [splines=ortho, overlap=false, ranksep=0.7, nodesep=0.45];',
+        '  node [fontname="Helvetica"];',
+    ]
+    color_nodes = set(annotations.keys()) | set((ru_edges or {}).keys())
+    node_colors = {nid: _node_color(nid) for nid in color_nodes}
+
+    def emit(node):
+        base_label = node.dot_label() or ""
+        shape = node.dot_shape
+        style = node.dot_style
+        style_str = f", {style}" if style else ""
+        lines.append(f'  n{node.id} [label="{base_label}", shape={shape}{style_str}];')
+
+        if node.id in annotations:
+            ann_id = f"a{node.id}"
+            ann_label = annotations[node.id].replace('"', '\\"')
+            edge_color, fill_color = node_colors.get(node.id, ("#1f77b4", "#d9ecff"))
+            lines.append(
+                f'  {ann_id} [label="{ann_label}", shape=note, '
+                f'style="filled", fillcolor="{fill_color}", color="{edge_color}", '
+                f'fontcolor="{edge_color}"];'
+            )
+            lines.append(
+                f'  {ann_id} -> n{node.id} [style=dotted, arrowhead=none, '
+                f'color="{edge_color}"];'
+            )
+
+        for i, child in enumerate(sorted(node.children, key=lambda n: n.id)):
+            edge_label = ""
+            if isinstance(node, CFG_DIAMOND):
+                if i == 0:
+                    edge_label = ' [label="T"]'
+                elif i == 1:
+                    edge_label = ' [label="F"]'
+            lines.append(f"  n{node.id} -> n{child.id}{edge_label};")
+
+    cfg.traverse(emit, start=cfg.START)
+
+    if ru_edges:
+        for idx, def_id in enumerate(sorted(ru_edges)):
+            use_ids = sorted(set(ru_edges[def_id]))
+            if not use_ids:
+                continue
+
+            # One routing hub per definition node to mimic UML-like
+            # "out to the side, then down/across to targets" connectors.
+            side = "e" if idx % 2 == 0 else "w"
+            source_port = "se" if side == "e" else "sw"
+            hub_id = f"rh{def_id}"
+            edge_color, fill_color = node_colors.get(def_id, ("#1f77b4", "#d9ecff"))
+
+            lines.append(
+                f'  {hub_id} [shape=point, width=0.05, height=0.05, '
+                f'color="{edge_color}", fillcolor="{edge_color}", style=filled];'
+            )
+            lines.append(f"  {{ rank=same; n{def_id}; {hub_id}; }}")
+            lines.append(
+                f'  n{def_id}:{source_port} -> {hub_id} [color="{edge_color}", '
+                f'style=dashed, penwidth=1.2, arrowhead=none, constraint=false, '
+                f'tailclip=true, headclip=true];'
+            )
+
+            for use_id in use_ids:
+                if side == "e":
+                    target_port = "ne" if (use_id % 2 == 0) else "se"
+                else:
+                    target_port = "nw" if (use_id % 2 == 0) else "sw"
+                lines.append(
+                    f'  {hub_id} -> n{use_id}:{target_port} [color="{edge_color}", '
+                    f'fontcolor="{edge_color}", fontsize=8, style=dashed, '
+                    f'penwidth=1.0, arrowsize=0.6, constraint=false, '
+                    f'tailclip=true, headclip=true];'
+                )
+
+    lines.append("}")
+    return "\n".join(lines)
--- a/Project-02-03-04-05/cfa/live_variables.py
+++ b/Project-02-03-04-05/cfa/live_variables.py
@@ -0,0 +1,351 @@
+"""
+live_variables.py — Live Variables backward dataflow analysis for TRIPLA CFGs.
+
+A variable v is *live* at the entry of node n if there exists a path
+n → … → use(v) where v is not redefined along the way.
+
+Data structures
+---------------
+gen      dict[int, set[Var]]   — GEN(n)  = variables *used* at n
+kill     dict[int, set[Var]]   — KILL(n) = variables *defined* at n
+in_sets  dict[int, set[Var]]   — live variables at node *entry*
+out_sets dict[int, set[Var]]   — live variables at node *exit*
+
+Transfer equations (backward):
+    OUT(n) = ∪ IN(s)           for all successors s
+    IN(n)  = (OUT(n) − KILL(n)) ∪ GEN(n)
+
+Variables are represented in scoped form ``(scope, name)``, e.g. ``("f","x")``.
+This avoids collisions between equal variable names in different functions.
+
+This module also exports ``_BackwardAnalysisBase``, the shared base class
+that ``ReachedUsesAnalysis`` in reached_uses.py inherits from.  The base
+provides:
+  • AST traversal to collect function-nesting and parameter metadata
+  • Lexical variable resolution (parameter shadowing handled correctly)
+  • BFS-based CFG-node → owning-function assignment
+  • Unified uses / defs extraction for all node types
+
+Var = tuple[str, str]
+"""
+from __future__ import annotations
+
+from collections import deque
+from typing import TYPE_CHECKING
+
+import cfg_build
+import syntax
+from cfg.CFG_Node import CFG_START
+
+if TYPE_CHECKING:
+    from cfg.CFG import CFG
+
+# ---------------------------------------------------------------------------
+# Public type alias  (imported by reached_uses.py)
+# ---------------------------------------------------------------------------
+
+GLOBAL_SCOPE = ""
+Var = tuple[str, str]   # (function_name|GLOBAL_SCOPE, variable_name)
+
+
+# ============================================================================
+# Shared base: function metadata, scope assignment, uses/defs extraction
+# ============================================================================
+
+class _BackwardAnalysisBase:
+    """Infrastructure shared by LiveVariablesAnalysis and ReachedUsesAnalysis.
+
+    Calling ``super().__init__(cfg)`` from a subclass:
+      1. Snapshots cfg_build.FUNCTIONS.
+      2. Collects AST-level function-nesting and parameter metadata.
+      3. BFS-assigns every CFG node to its owning function.
+      4. Extracts uses and defs for every CFG node.
+
+    After __init__ the following attributes are available to subclasses:
+
+        self.cfg          — the CFG object
+        self._functions   — dict[str, tuple]: snapshot of cfg_build.FUNCTIONS
+        self._func_parent — dict[str, str|None]: lexical parent per function
+        self._func_params — dict[str, tuple[str,...]]: params per function
+        self._func_scope  — dict[int, str]: node-id → owning function name
+        self.uses         — dict[int, set[Var]]: variables used at each node
+        self.defs         — dict[int, set[Var]]: variables defined at each node
+    """
+
+    def __init__(self, cfg: "CFG") -> None:
+        self.cfg = cfg
+        # Snapshot FUNCTIONS so later global-state resets do not affect us.
+        self._functions: dict[str, tuple] = dict(cfg_build.FUNCTIONS)
+
+        self.uses: dict[int, set[Var]] = {}
+        self.defs: dict[int, set[Var]] = {}
+
+        self._func_parent, self._func_params = self._collect_function_metadata()
+        self._func_scope: dict[int, str] = self._compute_function_scope()
+        self._extract_uses_defs()
+
+    # ------------------------------------------------------------------
+    # Step 1a — Walk AST to collect lexical nesting + parameter lists
+    # ------------------------------------------------------------------
+
+    def _collect_function_metadata(
+        self,
+    ) -> tuple[dict[str, str | None], dict[str, tuple[str, ...]]]:
+        """Walk the AST and collect function-parent and parameter information.
+
+        Returns
+        -------
+        func_parent : dict[str, str | None]
+            func_parent[f] is the name of the immediately enclosing function
+            (or None for top-level functions).
+        func_params : dict[str, tuple[str, ...]]
+            func_params[f] is the ordered tuple of formal parameter names of f.
+        """
+        func_parent: dict[str, str | None] = {}
+        func_params: dict[str, tuple[str, ...]] = {}
+
+        def visit(expr: syntax.EXPRESSION | None, current_func: str | None) -> None:
+            if expr is None:
+                return
+            if isinstance(expr, syntax.LET):
+                decls = expr.decl if isinstance(expr.decl, list) else [expr.decl]
+                # Register metadata for each declared function.
+                for d in decls:
+                    if isinstance(d, syntax.DECL):
+                        # Use assignment (last-seen wins) to stay consistent
+                        # with cfg_build.FUNCTIONS, which also overwrites on
+                        # duplicate names.  setdefault (first-seen wins) would
+                        # disagree when a nested function shadows a top-level
+                        # one with the same name, causing wrong scope resolution.
+                        func_parent[d.f_name] = current_func
+                        func_params[d.f_name] = tuple(d.params)
+                # Recurse into function bodies and the in-expression.
+                for d in decls:
+                    if isinstance(d, syntax.DECL):
+                        visit(d.body, d.f_name)
+                    else:
+                        visit(d, current_func)
+                visit(expr.body, current_func)
+                return
+            for _, child in expr.children():
+                visit(child, current_func)
+
+        visit(self.cfg.ast, None)
+        return func_parent, func_params
+
+    # ------------------------------------------------------------------
+    # Step 1b — Resolve a variable name through the lexical scope chain
+    # ------------------------------------------------------------------
+
+    def _resolve_var(self, func: str | None, name: str) -> Var:
+        """Resolve a variable name via lexical scope chain."""
+        if func is None:
+            return (GLOBAL_SCOPE, name)
+
+        cur: str | None = func
+        seen: set[str] = set()
+        while cur is not None and cur not in seen:
+            seen.add(cur)
+            if name in self._func_params.get(cur, ()):
+                return (cur, name)
+            cur = self._func_parent.get(cur)
+
+        # Fallback: local variable in current function scope.
+        return (func, name)
+
+    # ------------------------------------------------------------------
+    # Step 2 — BFS-assign every CFG node to its owning function
+    # ------------------------------------------------------------------
+
+    def _compute_function_scope(self) -> dict[int, str]:
+        """BFS from each function's START node; return node-id → function-name.
+
+        Two stopping conditions keep attribution strictly inside each function:
+
+        1. Do not follow into a *different* function's CFG_START (prevents
+           attributing callee body nodes to the caller, and vice-versa).
+        2. Do not follow *past* the function's own CFG_END (prevents
+           following CFG_END → CFG_RETURN → continuation nodes that belong
+           to the *caller* context, which caused variables used there to be
+           resolved in the wrong scope).
+
+        The first function whose BFS claims a node wins.
+        """
+        functions = self._functions
+        func_scope: dict[int, str] = {}
+        all_f_start_ids: set[int] = {fs.id for _, (fs, _) in functions.items()}
+
+        for f_name, (f_start, f_end) in functions.items():
+            queue: deque = deque([f_start])
+            while queue:
+                node = queue.popleft()
+                if node.id in func_scope:
+                    continue  # already claimed by an earlier function
+                func_scope[node.id] = f_name
+                # Stop here — do not follow CFG_END into caller context.
+                if node.id == f_end.id:
+                    continue
+                for child in node.children:
+                    # Do not follow into a different function's START.
+                    if (
+                        isinstance(child, CFG_START)
+                        and child.id in all_f_start_ids
+                        and child.id != f_start.id
+                    ):
+                        continue
+                    queue.append(child)
+
+        return func_scope
+
+    # ------------------------------------------------------------------
+    # Step 3 — Extract uses / defs for every CFG node
+    # ------------------------------------------------------------------
+
+    def _extract_uses_defs(self) -> None:
+        """Populate ``self.uses`` and ``self.defs`` for every node in the CFG.
+
+        Extraction rules:
+          • CFG_START(DECL f(p1,…,pk))  → defs  = {(f,p1), …, (f,pk)}
+          • Node wrapping ID(x)         → uses  = {lexical_resolve(func, x)}
+          • Node wrapping ASSIGN(x = e) → defs  = {lexical_resolve(func, x)}
+          • Everything else             → uses  = {}, defs = {}
+
+        Sub-expressions already have their own CFG nodes and are not
+        re-inspected here; each node is responsible only for its own ast_node.
+        """
+        for node in self.cfg.nodes():
+            nid  = node.id
+            func = self._func_scope.get(nid)   # None → outer / global scope
+            ast  = node.ast_node
+
+            uses: set[Var] = set()
+            defs: set[Var] = set()
+
+            if isinstance(node, CFG_START) and isinstance(ast, syntax.DECL):
+                # Function entry defines each formal parameter.
+                for param in ast.params:
+                    defs.add((ast.f_name, param))
+            elif ast is not None:
+                if isinstance(ast, syntax.ID):
+                    resolved = self._resolve_var(func, ast.name)
+                    uses.add(resolved)
+                elif isinstance(ast, syntax.ASSIGN):
+                    resolved = self._resolve_var(func, ast.var.name)
+                    defs.add(resolved)
+
+            self.uses[nid] = uses
+            self.defs[nid] = defs
+
+
+# ============================================================================
+# Live Variables Analysis
+# ============================================================================
+
+class LiveVariablesAnalysis(_BackwardAnalysisBase):
+    """Backward dataflow analysis: Live Variables.
+
+    A variable (f, x) is *live* at the entry of node n if there is a path
+    from n to some use of (f, x) along which (f, x) is not redefined.
+
+    This is the simpler predecessor to ReachedUsesAnalysis (reached_uses.py):
+    it tracks which variables are live, not *where* they are used.
+
+    Attributes
+    ----------
+    gen      dict[int, set[Var]]   GEN(n)  = uses(n)     — vars used at n
+    kill     dict[int, set[Var]]   KILL(n) = defs(n)     — vars defined at n
+    in_sets  dict[int, set[Var]]   live variables at n's *entry*
+    out_sets dict[int, set[Var]]   live variables at n's *exit*
+
+    (uses and defs are identical to gen / kill and are inherited from the
+    base class.)
+
+    Transfer equations (backward):
+        OUT(n) = ∪ IN(s)           for all successors s
+        IN(n)  = (OUT(n) − KILL(n)) ∪ GEN(n)
+    """
+
+    def __init__(self, cfg: "CFG") -> None:
+        # Base populates uses, defs, _func_scope, etc.
+        super().__init__(cfg)
+
+        self.gen:      dict[int, set[Var]] = {}
+        self.kill:     dict[int, set[Var]] = {}
+        self.in_sets:  dict[int, set[Var]] = {}
+        self.out_sets: dict[int, set[Var]] = {}
+
+        self._build_gen_kill()
+        self.solve()
+
+    # ------------------------------------------------------------------
+    # Build gen / kill; initialise in / out to ∅
+    # ------------------------------------------------------------------
+
+    def _build_gen_kill(self) -> None:
+        """GEN(n) = uses(n), KILL(n) = defs(n); initialise in/out sets."""
+        for node in self.cfg.nodes():
+            nid = node.id
+            self.gen[nid]      = set(self.uses[nid])
+            self.kill[nid]     = set(self.defs[nid])
+            self.in_sets[nid]  = set()
+            self.out_sets[nid] = set()
+
+    # ------------------------------------------------------------------
+    # Backward worklist fixpoint
+    # ------------------------------------------------------------------
+
+    def solve(self) -> None:
+        """Backward worklist until fixpoint.
+
+        Transfer:
+            OUT(n) = ∪ IN(s)           for all successors s
+            IN(n)  = (OUT(n) − KILL(n)) ∪ GEN(n)
+
+        Only nodes reachable from cfg.START are processed (guard against
+        propagate=False parent references from CFG.__remove_and_rewire).
+        """
+        nodes = list(self.cfg.nodes())
+        known: set[int] = set(self.gen.keys())
+        id_to_node = {n.id: n for n in nodes}
+        worklist: deque = deque(nodes)
+
+        # Build predecessor relation from children edges. This is more reliable
+        # than node.parents because CFG rewiring may add edges with
+        # propagate=False, leaving parent links stale.
+        preds: dict[int, set[int]] = {nid: set() for nid in known}
+        for node in nodes:
+            for child in node.children:
+                if child.id in known:
+                    preds[child.id].add(node.id)
+
+        while worklist:
+            node = worklist.popleft()
+            nid  = node.id
+
+            new_out: set[Var] = set()
+            for child in node.children:
+                if child.id in known:
+                    new_out |= self.in_sets[child.id]
+
+            new_in: set[Var] = (new_out - self.kill[nid]) | self.gen[nid]
+
+            if new_out != self.out_sets[nid] or new_in != self.in_sets[nid]:
+                self.out_sets[nid] = new_out
+                self.in_sets[nid]  = new_in
+                for pred_id in preds[nid]:
+                    worklist.append(id_to_node[pred_id])
+
+    # ------------------------------------------------------------------
+    # Result
+    # ------------------------------------------------------------------
+
+    def live_vars_by_node(self) -> dict[int, set[Var]]:
+        """Return the live-variable set at the *entry* of each node.
+
+        Returns
+        -------
+        dict[int, set[Var]]
+            Keys:   CFG node ids whose in_set is non-empty.
+            Values: copy of the live-variable set at that node's entry.
+        """
+        return {nid: set(vs) for nid, vs in self.in_sets.items() if vs}
--- a/Project-02-03-04-05/cfa/reached_uses.py
+++ b/Project-02-03-04-05/cfa/reached_uses.py
@@ -0,0 +1,203 @@
+"""
+reached_uses.py — Reached-Uses backward dataflow analysis for TRIPLA CFGs.
+
+Extends ``_BackwardAnalysisBase`` from live_variables.py, which provides the
+shared function-scope resolution and uses/defs extraction machinery.  The Live
+Variables analysis (LiveVariablesAnalysis) in that module is the simpler
+predecessor of this analysis (tip from the course notes: implement LV first,
+then extend to RU).
+
+How ReachedUsesAnalysis extends LiveVariablesAnalysis
+------------------------------------------------------
+Live Variables tracks *which* variables are live at each node (set[Var]).
+Reached Uses additionally tracks *where* each variable is used by attaching
+the use-node id to every fact, giving set[UseFact] = set[tuple[int, Var]].
+
+The transfer function changes accordingly:
+  LV:  IN(n) = (OUT(n) − KILL_LV(n)) ∪ GEN_LV(n)       [sets of Var]
+  RU:  IN(n) = (OUT(n) − KILL_RU(n)) ∪ GEN_RU(n)       [sets of UseFact]
+
+  GEN_LV(n)  = uses(n)                            — set[Var]
+  GEN_RU(n)  = { (n.id, var) | var ∈ uses(n) }   — set[UseFact]
+
+  KILL_LV(n) = defs(n)                            — set[Var]
+  KILL_RU(n) = { (uid, var) | var ∈ defs(n),      — set[UseFact]
+                  (uid, var) ∈ all_uses_by_var[var] }
+
+  The set-difference in both cases removes exactly the facts for variables
+  that are defined at n — equivalent to the ⊖ operator from the lecture
+  slides (M ⊖ K = {(p,id) ∈ M | id ∉ K}).
+
+Type aliases
+------------
+    Var     = tuple[str, str]       # (scope, variable_name)
+    UseFact = tuple[int, Var]       # (use_node_id, scoped_var)
+
+Analysis attributes (all populated after construction)
+------------------------------------------------------
+    uses            dict[int, set[Var]]
+    defs            dict[int, set[Var]]
+    gen             dict[int, set[UseFact]]
+    kill            dict[int, set[UseFact]]
+    in_sets         dict[int, set[UseFact]]
+    out_sets        dict[int, set[UseFact]]
+    all_uses_by_var dict[Var, set[UseFact]]
+
+Final result
+------------
+    reached_uses_by_node() → dict[int, list[int]]
+        Keys:   defining-node ids
+        Values: sorted, deduplicated list of use-node ids reached by the def
+"""
+from __future__ import annotations
+
+from collections import deque
+from typing import TYPE_CHECKING
+
+# Import the shared base class (and Var) from the Live Variables module.
+from cfa.live_variables import _BackwardAnalysisBase, Var
+
+if TYPE_CHECKING:
+    from cfg.CFG import CFG
+
+# ---------------------------------------------------------------------------
+# Public type aliases (re-exported so tests/reached_uses_stub.py can pick up
+# ReachedUsesAnalysis without needing to know about live_variables.py)
+# ---------------------------------------------------------------------------
+
+UseFact = tuple[int, Var]   # (use_node_id, scoped_var)
+
+
+# ============================================================================
+# Reached-Uses Analysis
+# ============================================================================
+
+class ReachedUsesAnalysis(_BackwardAnalysisBase):
+    """Backward dataflow analysis: Reached Uses.
+
+    Inherits uses/defs extraction and function-scope resolution from
+    _BackwardAnalysisBase (live_variables.py).  Extends it with use-fact
+    tracking: each fact carries the id of the node where the variable is used,
+    enabling def-use pairs to be recovered from the fixpoint solution.
+
+    Transfer equations (backward):
+        OUT(n) = ∪ IN(s)              for all successors s
+        IN(n)  = GEN(n) ∪ (OUT(n) − KILL(n))
+
+    GEN(n)  = { (n.id, var) | var ∈ uses(n) }
+    KILL(n) = { (uid, var) | var ∈ defs(n),
+                              (uid, var) ∈ all_uses_by_var[var] }
+    """
+
+    def __init__(self, cfg: "CFG") -> None:
+        # Base populates: uses, defs, _func_scope, _func_parent, _func_params.
+        super().__init__(cfg)
+
+        self.gen:             dict[int, set[UseFact]] = {}
+        self.kill:            dict[int, set[UseFact]] = {}
+        self.in_sets:         dict[int, set[UseFact]] = {}
+        self.out_sets:        dict[int, set[UseFact]] = {}
+        self.all_uses_by_var: dict[Var, set[UseFact]] = {}
+
+        self._build_gen_kill()
+        self.solve()
+
+    # ------------------------------------------------------------------
+    # Step 1 — Build gen, kill, all_uses_by_var; initialise in/out
+    # ------------------------------------------------------------------
+
+    def _build_gen_kill(self) -> None:
+        """Compute gen and kill sets; populate all_uses_by_var."""
+        # GEN[n] = { (n.id, var) | var ∈ uses[n] }
+        for node in self.cfg.nodes():
+            nid = node.id
+            self.gen[nid]      = {(nid, var) for var in self.uses[nid]}
+            self.in_sets[nid]  = set()
+            self.out_sets[nid] = set()
+
+        # all_uses_by_var: index all use-facts by their variable.
+        for nid, facts in self.gen.items():
+            for (uid, var) in facts:
+                self.all_uses_by_var.setdefault(var, set()).add((uid, var))
+
+        # KILL[n] = all use-facts for variables defined at n.
+        for node in self.cfg.nodes():
+            nid    = node.id
+            kill_n: set[UseFact] = set()
+            for var in self.defs[nid]:
+                if var in self.all_uses_by_var:
+                    kill_n |= self.all_uses_by_var[var]
+            self.kill[nid] = kill_n
+
+    # ------------------------------------------------------------------
+    # Step 2 — Backward worklist fixpoint
+    # ------------------------------------------------------------------
+
+    def solve(self) -> None:
+        """Backward worklist until fixpoint.
+
+        Transfer:
+            OUT(n) = ∪ IN(s)              for all successors s
+            IN(n)  = GEN(n) ∪ (OUT(n) − KILL(n))
+
+        Only nodes reachable from cfg.START are processed (guard against
+        propagate=False parent references from CFG.__remove_and_rewire).
+        """
+        nodes = list(self.cfg.nodes())
+        known: set[int] = set(self.gen.keys())   # ids of cfg.nodes()
+        id_to_node = {n.id: n for n in nodes}
+        worklist: deque = deque(nodes)
+
+        # Build predecessor relation from children edges. CFG rewiring may
+        # create edges with propagate=False, so node.parents can be stale.
+        preds: dict[int, set[int]] = {nid: set() for nid in known}
+        for node in nodes:
+            for child in node.children:
+                if child.id in known:
+                    preds[child.id].add(node.id)
+
+        while worklist:
+            node = worklist.popleft()
+            nid  = node.id
+
+            new_out: set[UseFact] = set()
+            for child in node.children:
+                if child.id in known:
+                    new_out |= self.in_sets[child.id]
+
+            new_in: set[UseFact] = self.gen[nid] | (new_out - self.kill[nid])
+
+            if new_out != self.out_sets[nid] or new_in != self.in_sets[nid]:
+                self.out_sets[nid] = new_out
+                self.in_sets[nid]  = new_in
+                for pred_id in preds[nid]:
+                    worklist.append(id_to_node[pred_id])
+
+    # ------------------------------------------------------------------
+    # Public result
+    # ------------------------------------------------------------------
+
+    def reached_uses_by_node(self) -> dict[int, list[int]]:
+        """Return the final reached-uses result.
+
+        For each defining node d:
+            result[d.id] = sorted list of use-node ids u such that
+                           (u, var) ∈ OUT[d] for some var ∈ defs[d].
+
+        Semantics: the definition at d of variable var reaches the use at u
+        if there is a CFG path d → … → u along which var is not redefined.
+
+        Only nodes with at least one definition appear as keys.
+        """
+        result: dict[int, list[int]] = {}
+        for node in self.cfg.nodes():
+            nid    = node.id
+            defs_n = self.defs[nid]
+            if not defs_n:
+                continue
+            reached: set[int] = set()
+            for (uid, var) in self.out_sets[nid]:
+                if var in defs_n:
+                    reached.add(uid)
+            result[nid] = sorted(reached)
+        return result
--- a/Project-02-03-04-05/cfadots/dataflow_analysis.dot
+++ b/Project-02-03-04-05/cfadots/dataflow_analysis.dot
@@ -0,0 +1,183 @@
+digraph CFG {
+  // Analysis: Live Variables + Reached Uses
+  graph [splines=ortho, overlap=false, ranksep=0.7, nodesep=0.45];
+  node [fontname="Helvetica"];
+  n1 [label="START", shape=ellipse, style=filled, color=gray];
+  n1 -> n3;
+  n3 [label="33", shape=box];
+  n3 -> n4;
+  n4 [label="s = 33", shape=box];
+  a4 [label="LivingVariables\nIn := []\nOut := [('', 's')]", shape=note, style="filled", fillcolor="#b2f7ec", color="#3fd1b9", fontcolor="#3fd1b9"];
+  a4 -> n4 [style=dotted, arrowhead=none, color="#3fd1b9"];
+  n4 -> n5;
+  n5 [label="0", shape=box];
+  n5 -> n6;
+  n6 [label="i = 0", shape=box];
+  a6 [label="LivingVariables\nIn := [('', 's')]\nOut := [('', 'i'), ('', 's')]", shape=note, style="filled", fillcolor="#c3b2f7", color="#633fd1", fontcolor="#633fd1"];
+  a6 -> n6 [style=dotted, arrowhead=none, color="#633fd1"];
+  n6 -> n7;
+  n7 [label="0", shape=box];
+  n7 -> n8;
+  n8 [label="j = 0", shape=box];
+  a8 [label="LivingVariables\nIn := [('', 'i'), ('', 's')]\nOut := [('', 'i'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#f7b2c9", color="#d13f70", fontcolor="#d13f70"];
+  a8 -> n8 [style=dotted, arrowhead=none, color="#d13f70"];
+  n8 -> n9;
+  n9 [label="i", shape=box];
+  n9 -> n10;
+  n10 [label="j", shape=box];
+  n10 -> n11;
+  n11 [label="i + j", shape=box];
+  n11 -> n12;
+  n12 [label="t = (i + j)", shape=box];
+  a12 [label="LivingVariables\nIn := [('', 'i'), ('', 'j'), ('', 's')]\nOut := [('', 'i'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#b2f7d5", color="#3fd188", fontcolor="#3fd188"];
+  a12 -> n12 [style=dotted, arrowhead=none, color="#3fd188"];
+  n12 -> n13;
+  n13 [label="6", shape=box];
+  n13 -> n14;
+  n14 [label="f = 6", shape=box];
+  a14 [label="LivingVariables\nIn := [('', 'i'), ('', 'j'), ('', 's')]\nOut := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#b2b8f7", color="#3f4bd1", fontcolor="#3f4bd1"];
+  a14 -> n14 [style=dotted, arrowhead=none, color="#3f4bd1"];
+  n14 -> n16;
+  n16 [label="s", shape=box];
+  n16 -> n17;
+  n17 [label="42", shape=box];
+  n17 -> n18;
+  n18 [label="s < 42", shape=box];
+  a18 [label="LivingVariables\nIn := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]\nOut := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#f7e6b2", color="#d1ac3f", fontcolor="#d1ac3f"];
+  a18 -> n18 [style=dotted, arrowhead=none, color="#d1ac3f"];
+  n18 -> n19;
+  n19 [label="<?>", shape=diamond];
+  n19 -> n2 [label="T"];
+  n19 -> n21 [label="F"];
+  n2 [label="END", shape=ellipse, style=filled, color=gray];
+  n21 [label="s", shape=box];
+  n21 -> n22;
+  n22 [label="1", shape=box];
+  n22 -> n23;
+  n23 [label="s - 1", shape=box];
+  n23 -> n24;
+  n24 [label="a = (s - 1)", shape=box];
+  a24 [label="LivingVariables\nIn := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]\nOut := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#f7b2f7", color="#d13fd1", fontcolor="#d13fd1"];
+  a24 -> n24 [style=dotted, arrowhead=none, color="#d13fd1"];
+  n24 -> n25;
+  n25 [label="i", shape=box];
+  n25 -> n26;
+  n26 [label="j", shape=box];
+  n26 -> n27;
+  n27 [label="i + j", shape=box];
+  n27 -> n28;
+  n28 [label="f", shape=box];
+  n28 -> n29;
+  n29 [label="1", shape=box];
+  n29 -> n30;
+  n30 [label="f + 1", shape=box];
+  n30 -> n31;
+  n31 [label="(i + j) * (f + 1)", shape=box];
+  n31 -> n32;
+  n32 [label="c = ((i + j) * (f + 1))", shape=box];
+  a32 [label="LivingVariables\nIn := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]\nOut := [('', 'c'), ('', 'f'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#e0b2f7", color="#a03fd1", fontcolor="#a03fd1"];
+  a32 -> n32 [style=dotted, arrowhead=none, color="#a03fd1"];
+  n32 -> n33;
+  n33 [label="c", shape=box];
+  n33 -> n34;
+  n34 [label="0", shape=box];
+  n34 -> n35;
+  n35 [label="c > 0", shape=box];
+  a35 [label="LivingVariables\nIn := [('', 'c'), ('', 'f'), ('', 'j'), ('', 's')]\nOut := [('', 'c'), ('', 'f'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#b2c1f7", color="#3f5ed1", fontcolor="#3f5ed1"];
+  a35 -> n35 [style=dotted, arrowhead=none, color="#3f5ed1"];
+  n35 -> n36;
+  n36 [label="<?>", shape=diamond];
+  n36 -> n40 [label="T"];
+  n36 -> n44 [label="F"];
+  n40 [label="j", shape=box];
+  n40 -> n41;
+  n41 [label="c", shape=box];
+  n41 -> n42;
+  n42 [label="j / c", shape=box];
+  n42 -> n43;
+  n43 [label="j = (j / c)", shape=box];
+  a43 [label="LivingVariables\nIn := [('', 'c'), ('', 'f'), ('', 'j'), ('', 's')]\nOut := [('', 'f'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#b2d8f7", color="#3f8fd1", fontcolor="#3f8fd1"];
+  a43 -> n43 [style=dotted, arrowhead=none, color="#3f8fd1"];
+  n43 -> n48;
+  n48 [label="j", shape=box];
+  n48 -> n49;
+  n49 [label="2", shape=box];
+  n49 -> n50;
+  n50 [label="j * 2", shape=box];
+  n50 -> n51;
+  n51 [label="f", shape=box];
+  n51 -> n52;
+  n52 [label="(j * 2) / f", shape=box];
+  n52 -> n53;
+  n53 [label="i = ((j * 2) / f)", shape=box];
+  a53 [label="LivingVariables\nIn := [('', 'f'), ('', 'j'), ('', 's')]\nOut := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#d7b2f7", color="#8d3fd1", fontcolor="#8d3fd1"];
+  a53 -> n53 [style=dotted, arrowhead=none, color="#8d3fd1"];
+  n53 -> n54;
+  n54 [label="s", shape=box];
+  n54 -> n55;
+  n55 [label="1", shape=box];
+  n55 -> n56;
+  n56 [label="s + 1", shape=box];
+  n56 -> n57;
+  n57 [label="s = (s + 1)", shape=box];
+  a57 [label="LivingVariables\nIn := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]\nOut := [('', 'f'), ('', 'i'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#def7b2", color="#9bd13f", fontcolor="#9bd13f"];
+  a57 -> n57 [style=dotted, arrowhead=none, color="#9bd13f"];
+  n57 -> n16;
+  n44 [label="j", shape=box];
+  n44 -> n45;
+  n45 [label="c", shape=box];
+  n45 -> n46;
+  n46 [label="j * c", shape=box];
+  n46 -> n47;
+  n47 [label="i = (j * c)", shape=box];
+  a47 [label="LivingVariables\nIn := [('', 'c'), ('', 'f'), ('', 'j'), ('', 's')]\nOut := [('', 'f'), ('', 'j'), ('', 's')]", shape=note, style="filled", fillcolor="#f7c6b2", color="#d1693f", fontcolor="#d1693f"];
+  a47 -> n47 [style=dotted, arrowhead=none, color="#d1693f"];
+  n47 -> n48;
+  rh4 [shape=point, width=0.05, height=0.05, color="#3fd1b9", fillcolor="#3fd1b9", style=filled];
+  { rank=same; n4; rh4; }
+  n4:se -> rh4 [color="#3fd1b9", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh4 -> n16:ne [color="#3fd1b9", fontcolor="#3fd1b9", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh4 -> n21:se [color="#3fd1b9", fontcolor="#3fd1b9", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh4 -> n54:ne [color="#3fd1b9", fontcolor="#3fd1b9", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh6 [shape=point, width=0.05, height=0.05, color="#633fd1", fillcolor="#633fd1", style=filled];
+  { rank=same; n6; rh6; }
+  n6:sw -> rh6 [color="#633fd1", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh6 -> n9:sw [color="#633fd1", fontcolor="#633fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh6 -> n25:sw [color="#633fd1", fontcolor="#633fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh8 [shape=point, width=0.05, height=0.05, color="#d13f70", fillcolor="#d13f70", style=filled];
+  { rank=same; n8; rh8; }
+  n8:se -> rh8 [color="#d13f70", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh8 -> n10:ne [color="#d13f70", fontcolor="#d13f70", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh8 -> n26:ne [color="#d13f70", fontcolor="#d13f70", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh8 -> n40:ne [color="#d13f70", fontcolor="#d13f70", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh8 -> n44:ne [color="#d13f70", fontcolor="#d13f70", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh8 -> n48:ne [color="#d13f70", fontcolor="#d13f70", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh14 [shape=point, width=0.05, height=0.05, color="#3f4bd1", fillcolor="#3f4bd1", style=filled];
+  { rank=same; n14; rh14; }
+  n14:se -> rh14 [color="#3f4bd1", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh14 -> n28:ne [color="#3f4bd1", fontcolor="#3f4bd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh14 -> n51:se [color="#3f4bd1", fontcolor="#3f4bd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh32 [shape=point, width=0.05, height=0.05, color="#a03fd1", fillcolor="#a03fd1", style=filled];
+  { rank=same; n32; rh32; }
+  n32:se -> rh32 [color="#a03fd1", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh32 -> n33:se [color="#a03fd1", fontcolor="#a03fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh32 -> n41:se [color="#a03fd1", fontcolor="#a03fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh32 -> n45:se [color="#a03fd1", fontcolor="#a03fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh43 [shape=point, width=0.05, height=0.05, color="#3f8fd1", fillcolor="#3f8fd1", style=filled];
+  { rank=same; n43; rh43; }
+  n43:sw -> rh43 [color="#3f8fd1", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh43 -> n26:nw [color="#3f8fd1", fontcolor="#3f8fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh43 -> n40:nw [color="#3f8fd1", fontcolor="#3f8fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh43 -> n44:nw [color="#3f8fd1", fontcolor="#3f8fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh43 -> n48:nw [color="#3f8fd1", fontcolor="#3f8fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh53 [shape=point, width=0.05, height=0.05, color="#8d3fd1", fillcolor="#8d3fd1", style=filled];
+  { rank=same; n53; rh53; }
+  n53:sw -> rh53 [color="#8d3fd1", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh53 -> n25:sw [color="#8d3fd1", fontcolor="#8d3fd1", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh57 [shape=point, width=0.05, height=0.05, color="#9bd13f", fillcolor="#9bd13f", style=filled];
+  { rank=same; n57; rh57; }
+  n57:se -> rh57 [color="#9bd13f", style=dashed, penwidth=1.2, arrowhead=none, constraint=false, tailclip=true, headclip=true];
+  rh57 -> n16:ne [color="#9bd13f", fontcolor="#9bd13f", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh57 -> n21:se [color="#9bd13f", fontcolor="#9bd13f", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+  rh57 -> n54:ne [color="#9bd13f", fontcolor="#9bd13f", fontsize=8, style=dashed, penwidth=1.0, arrowsize=0.6, constraint=false, tailclip=true, headclip=true];
+}
--- a/Project-02-03-04-05/cfg_build.py
+++ b/Project-02-03-04-05/cfg_build.py
@@ -148,11 +148,15 @@ class IF(compiler.IF):

 class WHILE(compiler.WHILE):
    def cfa(self, pred, end = None):
+        # Dedicated loop-head so every iteration re-evaluates the full condition.
+        cond_entry = CFG_Node()
+        pred.add_child(cond_entry)
+
        if hasattr(self.cond, 'arg1') and hasattr(self.cond, 'arg2'):
            # This is a comparison operation (e.g., a > b)

            # Create the condition evaluation nodes
-            left_node = self.cond.arg1.cfa(pred)
+            left_node = self.cond.arg1.cfa(cond_entry)
            right_node = self.cond.arg2.cfa(left_node)

            # Create the comparison node and attach
@@ -161,7 +165,7 @@ class WHILE(compiler.WHILE):
            right_node.add_child(comp_node)
        else:
            # This is a simple condition (e.g., constant true/false)
-            cond_node = self.cond.cfa(pred)
+            cond_node = self.cond.cfa(cond_entry)
            comp_node = cond_node
        
        # Attach junction node
@@ -175,11 +179,8 @@ class WHILE(compiler.WHILE):
        # The body should connect back to the start of condition evaluation
        body_end = self.body.cfa(body_entry)
        if body_end is not None:
-            # Connect the body end back to the condition evaluation
-            if hasattr(self.cond, 'arg1') and hasattr(self.cond, 'arg2'):
-                body_end.add_child(left_node)
-            else:
-                body_end.add_child(pred)
+            # Connect loop body back to full condition evaluation.
+            body_end.add_child(cond_entry)

        # Attach joining node
        after = CFG_Node()
--- a/Project-02-03-04-05/cfgdots/smoke_test_simple_dfa_reached_uses.dot
+++ b/Project-02-03-04-05/cfgdots/smoke_test_simple_dfa_reached_uses.dot
@@ -0,0 +1,24 @@
+digraph CFG {
+  // Analysis: Reached Uses
+  node [fontname="Helvetica"];
+  n1 [label="START", shape=ellipse, style=filled, color=gray];
+  n1 -> n9;
+  n9 [label="2", shape=box];
+  n9 -> n10;
+  n10 [label="CALL g", shape=box, style=filled, color=orange];
+  n10 -> n3;
+  n10 -> n12;
+  n3 [label="START g(x, y)\nRU: [8]", shape=ellipse, style=filled, color=green];
+  n3 -> n6;
+  n6 [label="3", shape=box];
+  n6 -> n7;
+  n7 [label="y = 3\nRU: []", shape=box];
+  n7 -> n8;
+  n8 [label="x", shape=box];
+  n8 -> n4;
+  n4 [label="END g(x, y)", shape=ellipse, style=filled, color=green];
+  n4 -> n12;
+  n12 [label="RET g", shape=box, style=filled, color=orange];
+  n12 -> n2;
+  n2 [label="END", shape=ellipse, style=filled, color=gray];
+}
--- a/Project-02-03-04-05/main.py
+++ b/Project-02-03-04-05/main.py
@@ -7,9 +7,11 @@ import matplotlib.image as mpimg
 import matplotlib.pyplot as plt
 from graphviz import Source

+import cfg_build
 import lib.console as cnsl
 import syntax
 import triplayacc as yacc
+from cfa.analysis_dot import analysis_to_dot, run_all_analyses
 from cfg.CFG import CFG
 from vistram.tram import *
 from vistram.vistram import MachineUI
@@ -63,13 +65,54 @@ def pretty_print(node, indent=0):
            print(f"{prefix}  {key}: {value}")


+def print_analysis_reports(cfg, analyses: dict, ru_edges: dict[int, list[int]]):
+    """Print compact Live Variables and Reached Uses reports to console."""
+    lv = analyses["lv"]
+    ru = analyses["ru"]
+    _ = ru
+    node_by_id = {n.id: n for n in cfg.nodes()}
+
+    def node_text(nid: int) -> str:
+        node = node_by_id.get(nid)
+        if node is None:
+            return "<unknown>"
+        lbl = node.dot_label()
+        return str(lbl) if lbl is not None else "<no-label>"
+
+    print("\nLive Variables Report")
+    print("---------------------")
+    node_ids = sorted(set(lv.in_sets.keys()) | set(lv.out_sets.keys()))
+    for nid in node_ids:
+        in_set = sorted(lv.in_sets.get(nid, set()))
+        out_set = sorted(lv.out_sets.get(nid, set()))
+        if not in_set and not out_set:
+            continue
+        print(f"n{nid} [{node_text(nid)}]: In={in_set} Out={out_set}")
+
+    print("\nReached Uses Report")
+    print("-------------------")
+    has_ru = False
+    for def_id in sorted(ru_edges):
+        uses = sorted(set(ru_edges[def_id]))
+        if not uses:
+            continue
+        has_ru = True
+        use_desc = [f"n{uid} [{node_text(uid)}]" for uid in uses]
+        print(f"n{def_id} [{node_text(def_id)}] -> {use_desc}")
+    if not has_ru:
+        print("(no reached uses)")
+
+
 if __name__ == "__main__":
    print("\nTRIPLA Parser and TRIPLA to TRAM Compiler")

    while True:
-        mode = cnsl.prompt_choice("\nSelect action:", ["Parse .tripla", "Compile .tripla", "CFG for .tripla", "Exit"])
+        mode = cnsl.prompt_choice(
+            "\nSelect action:",
+            ["Parse .tripla", "Compile .tripla", "CFG for .tripla", "Analyze .tripla", "Exit"],
+        )

-        if mode == 3:
+        if mode == 4:
            print("\nBye Bye.")
            break

@@ -157,6 +200,7 @@ if __name__ == "__main__":
                    filename = default

                out_path = Path(__file__).parent / 'cfgdots' / filename
+                out_path.parent.mkdir(exist_ok=True)
                with open(out_path, "w") as f:
                    f.write(dot_str)

@@ -166,6 +210,46 @@ if __name__ == "__main__":
                render_diagram(dot_str)
                print("Rendered CFG diagram.")

+        elif mode == 3:
+            # Reset global CFG builder state so each analysis run is clean
+            cfg_build.FUNCTIONS.clear()
+            cfg_build.CURRENT_FUNCTION = None

+            cfg = make_cfg(ast)
+            analysis_name = "Live Variables + Reached Uses"
+            print(f"\nRunning {analysis_name} …")
+            try:
+                _analyses, annotations, ru_edges = run_all_analyses(cfg)
+            except Exception as exc:
+                print(f"Analysis failed: {exc}")
+                continue

+            print(
+                f"Done. {len(annotations)} LV annotation node(s), "
+                f"{len(ru_edges)} RU definition node(s)."
+            )

+            dot_str = analysis_to_dot(cfg, annotations, analysis_name, ru_edges)
+
+            if cnsl.prompt_confirmation("\nPrint analysis reports to console?"):
+                print_analysis_reports(cfg, _analyses, ru_edges)
+
+            if cnsl.prompt_confirmation("\nExport annotated CFG as .dot file?"):
+                default = f"{path.stem}_analysis.dot"
+                filename = input(f"Filename [{default}]: ").strip()
+                if not filename:
+                    filename = default
+
+                out_dir = Path(__file__).parent / "cfadots"
+                out_dir.mkdir(exist_ok=True)
+                out_path = out_dir / filename
+                try:
+                    with open(out_path, "w") as f:
+                        f.write(dot_str)
+                    print(f"Saved annotated DOT file as: {out_path}")
+                except Exception as exc:
+                    print(f"Could not save DOT file: {exc}")
+
+            if cnsl.prompt_confirmation("Display annotated CFG diagram?"):
+                render_diagram(dot_str)
+                print("Rendered annotated CFG diagram.")
--- a/Project-02-03-04-05/triplaprograms/dataflow.tripla
+++ b/Project-02-03-04-05/triplaprograms/dataflow.tripla
@@ -0,0 +1,12 @@
+s = 33;
+i = 0;
+j = 0;
+t = i + j;
+f = 6;
+while (s < 42) do {
+    a = s - 1;
+    c = (i + j) * (f + 1);
+    if (c > 0) then j = j / c else i = j * c;
+    i = (j * 2) / f;
+    s = s + 1
+}
--- a/Project-02-03-04-05/triplaprograms/reached.tripla
+++ b/Project-02-03-04-05/triplaprograms/reached.tripla
@@ -0,0 +1,9 @@
+let f(x,y,z) {
+    y = 2;
+    z = 3;
+    let g(x) {
+        x = 7;
+        if (y > 0) then g(y) else x = 8;
+        x
+    } in g(x) + x
+} in f(2,3)