From e7fa09e4ae8ae50419010cac056637733e297c8c Mon Sep 17 00:00:00 2001
From: Nico Weber <nicolasweber@gmx.de>
Date: Tue, 30 Apr 2019 19:43:35 +0000
Subject: [PATCH] Fix stack-use-after free after r359580

`Candidate` was a StringRef refering to a temporary string.
Instead, create a local variable for the string and use
a StringRef referring to that.

llvm-svn: 359604
---
 llvm/lib/Option/OptTable.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Option/OptTable.cpp b/llvm/lib/Option/OptTable.cpp
index 8956c6830dbb..1585059c2fba 100644
--- a/llvm/lib/Option/OptTable.cpp
+++ b/llvm/lib/Option/OptTable.cpp
@@ -296,10 +296,11 @@ unsigned OptTable::findNearest(StringRef Option, std::string &NearestString,
     // "--help" over "-help".
     for (int P = 0; const char *const CandidatePrefix = CandidateInfo.Prefixes[P]; P++) {
       std::string NormalizedName = (LHS + Delimiter).str();
-      StringRef Candidate = (CandidatePrefix + CandidateName).str();
+      std::string Candidate = (CandidatePrefix + CandidateName).str();
+      StringRef CandidateRef = Candidate;
       unsigned Distance =
-          Candidate.edit_distance(NormalizedName, /*AllowReplacements=*/true,
-                                  /*MaxEditDistance=*/BestDistance);
+          CandidateRef.edit_distance(NormalizedName, /*AllowReplacements=*/true,
+                                     /*MaxEditDistance=*/BestDistance);
       if (Distance < BestDistance) {
         BestDistance = Distance;
         NearestString = (Candidate + RHS).str();