From 4c3b875a0b3e57f0b9c42bfc14b1e48cadef73b3 Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Tue, 29 Mar 2016 05:25:17 +0000
Subject: [PATCH] BitcodeReader: Allow METADATA_STRINGS to only have !""

Support parsing a METADATA_STRINGS record that only has a single piece
of metadata, !"".  Fixes a corner case in r264551.

llvm-svn: 264699
---
 lib/Bitcode/Reader/BitcodeReader.cpp       | 2 +-
 test/Bitcode/metadata-only-empty-string.ll | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)
 create mode 100644 test/Bitcode/metadata-only-empty-string.ll

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index cb2784ff204..72ac217bef2 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1899,7 +1899,7 @@ std::error_code BitcodeReader::parseMetadataStrings(ArrayRef<uint64_t> Record,
   unsigned StringsOffset = Record[1];
   if (!NumStrings)
     return error("Invalid record: metadata strings with no strings");
-  if (StringsOffset >= Blob.size())
+  if (StringsOffset > Blob.size())
     return error("Invalid record: metadata strings corrupt offset");
 
   StringRef Lengths = Blob.slice(0, StringsOffset);
diff --git a/test/Bitcode/metadata-only-empty-string.ll b/test/Bitcode/metadata-only-empty-string.ll
new file mode 100644
index 00000000000..f8331e35985
--- /dev/null
+++ b/test/Bitcode/metadata-only-empty-string.ll
@@ -0,0 +1,7 @@
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+; CHECK: !named = !{!0}
+!named = !{!0}
+
+; CHECK: !0 = !{!""}
+!0 = !{!""}