From: Shoaib Meenai <smeenai@fb.com>
Date: Tue, 28 Apr 2020 18:29:30 +0000 (-0700)
Subject: [MachO] Fix UB in memcpy
X-Git-Tag: llvmorg-12-init~7565
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=af40bff32db7840cfbe07278ff0c498604acc5f0;p=platform%2Fupstream%2Fllvm.git

[MachO] Fix UB in memcpy

UBSan complains about a memcpy with a null pointer, so just skip the
memcpy call if the data is empty.
---

diff --git a/lld/MachO/InputSection.cpp b/lld/MachO/InputSection.cpp
index 76cf874..8c4a50b 100644
--- a/lld/MachO/InputSection.cpp
+++ b/lld/MachO/InputSection.cpp
@@ -26,7 +26,8 @@ uint64_t InputSection::getFileOffset() const {
 }
 
 void InputSection::writeTo(uint8_t *buf) {
-  memcpy(buf, data.data(), data.size());
+  if (!data.empty())
+    memcpy(buf, data.data(), data.size());
 
   for (Reloc &r : relocs) {
     uint64_t va = 0;