From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Thu, 10 Dec 2015 16:35:06 +0000 (+0000)
Subject: Avoid undefined behavior when vector is empty.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4d1332c4e7d3c428f5c5a9b08f02ea70deeac283;p=oota-llvm.git

Avoid undefined behavior when vector is empty.

Found by ubsan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255258 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/ADT/SetVector.h b/include/llvm/ADT/SetVector.h
index 3ab202d8d71..bc563570c20 100644
--- a/include/llvm/ADT/SetVector.h
+++ b/include/llvm/ADT/SetVector.h
@@ -58,6 +58,8 @@ public:
     insert(Start, End);
   }
 
+  ArrayRef<T> getArrayRef() const { return vector_; }
+
   /// \brief Determine if the SetVector is empty or not.
   bool empty() const {
     return vector_.empty();
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 3d3454f3f7f..a596697e8f5 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -772,8 +772,7 @@ bool ModuleLinker::run() {
       Internalize.insert(GV->getName());
   }
 
-  if (Mover.move(SrcM,
-                 makeArrayRef(&*ValuesToLink.begin(), ValuesToLink.size()),
+  if (Mover.move(SrcM, ValuesToLink.getArrayRef(),
                  [this](GlobalValue &GV, IRMover::ValueAdder Add) {
                    addLazyFor(GV, Add);
                  }))