[PATCH] D26638: Don't pass nullptr into memcpy

[Vitaly Buka via llvm-commits]

vitalybuka created this revision.
vitalybuka added reviewers: rnk, zturner.
vitalybuka added a subscriber: llvm-commits.

It's undefined according UBSAN.
Not sure which CL caused test failures, but seems writeBytes for empty buffer
should be OK.


https://reviews.llvm.org/D26638

Files:
  include/llvm/DebugInfo/MSF/ByteStream.h


Index: include/llvm/DebugInfo/MSF/ByteStream.h
===================================================================
--- include/llvm/DebugInfo/MSF/ByteStream.h
+++ include/llvm/DebugInfo/MSF/ByteStream.h
@@ -97,7 +97,8 @@
       return make_error<MSFError>(msf_error_code::insufficient_buffer);
 
     uint8_t *DataPtr = const_cast<uint8_t *>(Data.data());
-    ::memcpy(DataPtr + Offset, Buffer.data(), Buffer.size());
+    if (!Buffer.empty())
+      ::memcpy(DataPtr + Offset, Buffer.data(), Buffer.size());
     return Error::success();
   }
 


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