[llvm] r220567 - [Object] Fix MachO's getUuid to return a pointer into the object instead of a dangling ArrayRef.

[Benjamin Kramer]

Author: d0k
Date: Fri Oct 24 10:52:05 2014
New Revision: 220567

URL: http://llvm.org/viewvc/llvm-project?rev=220567&view=rev
Log:
[Object] Fix MachO's getUuid to return a pointer into the object instead of a dangling ArrayRef.

This works because uuid's are always little endian so it's not swapped.
Fixes use-after-return reported by asan.

Modified:
    llvm/trunk/lib/Object/MachOObjectFile.cpp

Modified: llvm/trunk/lib/Object/MachOObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/MachOObjectFile.cpp?rev=220567&r1=220566&r2=220567&view=diff
==============================================================================
--- llvm/trunk/lib/Object/MachOObjectFile.cpp (original)
+++ llvm/trunk/lib/Object/MachOObjectFile.cpp Fri Oct 24 10:52:05 2014
@@ -2460,8 +2460,9 @@ ArrayRef<uint8_t> MachOObjectFile::getDy
 ArrayRef<uint8_t> MachOObjectFile::getUuid() const {
   if (!UuidLoadCmd)
     return ArrayRef<uint8_t>();
-  MachO::uuid_command Uuid = getStruct<MachO::uuid_command>(this, UuidLoadCmd);
-  return ArrayRef<uint8_t>(Uuid.uuid, 16);
+  // Returning a pointer is fine as uuid doesn't need endian swapping.
+  const char *Ptr = UuidLoadCmd + offsetof(MachO::uuid_command, uuid);
+  return ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(Ptr), 16);
 }
 
 StringRef MachOObjectFile::getStringTableData() const {