[clang] [clang][StaticAnalyzer] Crash on loop unrolling mode (PR #82089)

[via cfe-commits]

https://github.com/huang-me created https://github.com/llvm/llvm-project/pull/82089

StaticAnalyzer didn't check if the variable is declared in `CompoundStmt` under `SwitchStmt`, which make static analyzer reach root without finding the declaration.

Fixes #68819

>From a590abda0570d922eb7032096de6fdd8cbbe4c63 Mon Sep 17 00:00:00 2001
From: huang-me <amos0107 at gmail.com>
Date: Sat, 17 Feb 2024 10:43:48 +0800
Subject: [PATCH] Fix crash on StaticAnalyzer loop unrolling

---
 clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp b/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp
index a80352816be613..b91dfa26774aa4 100644
--- a/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp
+++ b/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp
@@ -226,6 +226,17 @@ static bool isPossiblyEscaped(ExplodedNode *N, const DeclRefExpr *DR) {
           return false;
       }
     }
+
+    if (const SwitchStmt *SS = dyn_cast<SwitchStmt>(S)) {
+      for(const Stmt *CB: dyn_cast<CompoundStmt>(SS->getBody())->body()) {
+        for (const Decl *D : dyn_cast<DeclStmt>(CB)->decls()) {
+          // Once we reach the declaration of the VD we can return.
+          if (D->getCanonicalDecl() == VD)
+            return false;
+        }
+      }
+    }
+
     // Check the usage of the pass-by-ref function calls and adress-of operator
     // on VD and reference initialized by VD.
     ASTContext &ASTCtx =