docs: 补充注释与格式化

crates/oxide_cfg/src/finalize.rs

@@ -4,7 +4,11 @@ use crate::{BasicBlock, Cfg};
 
 /// 追加 exit 哨兵块（`0..0`，置末尾），从各块 succs 反推 preds。
 pub(super) fn finalize(mut blocks: Vec<BasicBlock>, exit_id: usize) -> Cfg {
-    blocks.push(BasicBlock { inst_range: 0..0, preds: Vec::new(), succs: Vec::new() });
+    blocks.push(BasicBlock {
+        inst_range: 0..0,
+        preds: Vec::new(),
+        succs: Vec::new(),
+    });
     let mut succs_total = 0usize;
     let mut preds_total = 0usize;
     for i in 0..blocks.len() {
@@ -17,7 +21,11 @@ pub(super) fn finalize(mut blocks: Vec<BasicBlock>, exit_id: usize) -> Cfg {
     }
     debug_assert_eq!(succs_total, preds_total, "succs/preds 不对称（Pitfall 4）");
 
-    Cfg { blocks, entry: 0, exit: exit_id }
+    Cfg {
+        blocks,
+        entry: 0,
+        exit: exit_id,
+    }
 }
 
 #[cfg(test)]
@@ -29,8 +37,16 @@ mod tests {
     #[test]
     fn exit_sentinel_appended_with_preds_reversed() {
         let blocks_in = vec![
-            BasicBlock { inst_range: 0..1, preds: Vec::new(), succs: vec![(1, EdgeKind::Jump)] },
-            BasicBlock { inst_range: 1..2, preds: Vec::new(), succs: vec![(2, EdgeKind::Fallthrough)] },
+            BasicBlock {
+                inst_range: 0..1,
+                preds: Vec::new(),
+                succs: vec![(1, EdgeKind::Jump)],
+            },
+            BasicBlock {
+                inst_range: 1..2,
+                preds: Vec::new(),
+                succs: vec![(2, EdgeKind::Fallthrough)],
+            },
         ];
         let cfg = finalize(blocks_in, 2);
         assert_eq!(cfg.blocks.len(), 3, "2 实块 + exit 哨兵");
@@ -41,12 +57,20 @@ mod tests {
         assert_eq!(cfg.blocks[2].preds, vec![1], "exit preds 反推自块 1 的 Fallthrough 边");
     }
 
-    /// succs/preds 对称：total 边数一致（Pitfall 4 防御性约束）。
+    /// succs/preds 对称：total 边数一致（防御性约束）。
     #[test]
     fn preds_and_succs_symmetric() {
         let blocks_in = vec![
-            BasicBlock { inst_range: 0..1, preds: Vec::new(), succs: vec![(1, EdgeKind::Jump)] },
-            BasicBlock { inst_range: 1..2, preds: Vec::new(), succs: vec![(2, EdgeKind::Fallthrough)] },
+            BasicBlock {
+                inst_range: 0..1,
+                preds: Vec::new(),
+                succs: vec![(1, EdgeKind::Jump)],
+            },
+            BasicBlock {
+                inst_range: 1..2,
+                preds: Vec::new(),
+                succs: vec![(2, EdgeKind::Fallthrough)],
+            },
         ];
         let cfg = finalize(blocks_in, 2);
         let succs_total: usize = cfg.blocks.iter().map(|b| b.succs.len()).sum();