From c99827349927a44334f2b04139168efd0bc87cd3 Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein.wu@gmail.com>
Date: Fri, 1 Jul 2022 20:16:06 +0200
Subject: [PATCH] [pseudo] Fix an out-of-bound issue in getReduceRules.

---
 .../pseudo/include/clang-pseudo/grammar/LRTable.h            | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h b/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h
index 70ce52924f11..664a1a3206fe 100644
--- a/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h
+++ b/clang-tools-extra/pseudo/include/clang-pseudo/grammar/LRTable.h
@@ -140,8 +140,11 @@ public:
   //     // ...apply reduce...
   //   }
   llvm::ArrayRef<RuleID> getReduceRules(StateID State) const {
+    if (ReduceOffset[State] >= Reduces.size())
+      return {};
+    size_t Length = ReduceOffset[State + 1] - ReduceOffset[State];
     return llvm::makeArrayRef(&Reduces[ReduceOffset[State]],
-                              &Reduces[ReduceOffset[State + 1]]);
+                              Length);
   }
   // Returns whether Terminal can follow Nonterminal in a valid source file.
   bool canFollow(SymbolID Nonterminal, SymbolID Terminal) const {