From 2cd7d385086b67541612136903367096a7156b27 Mon Sep 17 00:00:00 2001
From: Tom Hvitved <hvitved@github.com>
Date: Thu, 7 Nov 2024 10:00:24 +0100
Subject: [PATCH] break

---
 .../lib/codeql/rust/controlflow/CfgNodes.qll  | 37 +++++++++++++++++++
 .../rust/controlflow/internal/CfgNodes.qll    |  4 ++
 2 files changed, 41 insertions(+)

diff --git a/rust/ql/lib/codeql/rust/controlflow/CfgNodes.qll b/rust/ql/lib/codeql/rust/controlflow/CfgNodes.qll
index fcbb2ab4cfc0..0dd5404ebcea 100644
--- a/rust/ql/lib/codeql/rust/controlflow/CfgNodes.qll
+++ b/rust/ql/lib/codeql/rust/controlflow/CfgNodes.qll
@@ -93,3 +93,40 @@ final class BlockExprCfgNode extends Nodes::BlockExprCfgNode {
    */
   ExprCfgNode getTailExpr() { node.hasCfgChild(node.getStmtList().getTailExpr(), this, result) }
 }
+
+/**
+ * A break expression. For example:
+ * ```rust
+ * loop {
+ *     if not_ready() {
+ *         break;
+ *      }
+ * }
+ * ```
+ * ```rust
+ * let x = 'label: loop {
+ *     if done() {
+ *         break 'label 42;
+ *     }
+ * };
+ * ```
+ * ```rust
+ * let x = 'label: {
+ *     if exit() {
+ *         break 'label 42;
+ *     }
+ *     0;
+ * };
+ * ```
+ */
+final class BreakExprCfgNode extends Nodes::BreakExprCfgNode {
+  /**
+   * Gets the target of this `break` expression.
+   *
+   * The target is either a `LoopExpr`, a `ForExpr`, a `WhileExpr`, or a
+   * `BlockExpr`.
+   */
+  ExprCfgNode getTarget() {
+    any(BreakExprTargetChildMapping node).hasCfgChild(this.getBreakExpr(), result, this)
+  }
+}
diff --git a/rust/ql/lib/codeql/rust/controlflow/internal/CfgNodes.qll b/rust/ql/lib/codeql/rust/controlflow/internal/CfgNodes.qll
index d5328661475b..04c8e20ebf54 100644
--- a/rust/ql/lib/codeql/rust/controlflow/internal/CfgNodes.qll
+++ b/rust/ql/lib/codeql/rust/controlflow/internal/CfgNodes.qll
@@ -57,6 +57,10 @@ class BlockExprChildMapping extends ChildMapping, BlockExpr {
   override predicate relevantChild(AstNode child) { child = this.getStmtList().getTailExpr() }
 }
 
+class BreakExprTargetChildMapping extends ChildMapping, Expr {
+  override predicate relevantChild(AstNode child) { child.(BreakExpr).getTarget() = this }
+}
+
 private class ChildMappingImpl extends ChildMapping {
   ChildMappingImpl() { exists(this) }