[llvm] r341343 - [NFC][llvm-objcopy] Fixing a ubi-san problem with unaligned memory writes.

[Puyan Lotfi via llvm-commits]

Author: zer0
Date: Mon Sep  3 18:57:30 2018
New Revision: 341343

URL: http://llvm.org/viewvc/llvm-project?rev=341343&view=rev
Log:
[NFC][llvm-objcopy] Fixing a ubi-san problem with unaligned memory writes.

Modified:
    llvm/trunk/tools/llvm-objcopy/Object.cpp

Modified: llvm/trunk/tools/llvm-objcopy/Object.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/Object.cpp?rev=341343&r1=341342&r2=341343&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-objcopy/Object.cpp (original)
+++ llvm/trunk/tools/llvm-objcopy/Object.cpp Mon Sep  3 18:57:30 2018
@@ -153,9 +153,10 @@ void ELFSectionWriter<ELFT>::visit(const
     ArrayRef<uint8_t> Magic = {'Z', 'L', 'I', 'B'};
     std::copy(Magic.begin(), Magic.end(), Buf);
     Buf += Magic.size();
-    uint64_t *DecompressedSizePtr = reinterpret_cast<uint64_t *>(Buf);
-    *DecompressedSizePtr = support::endian::read64be(&Sec.DecompressedSize);
-    Buf += sizeof(Sec.DecompressedSize);
+    const uint64_t DecompressedSize =
+        support::endian::read64be(&Sec.DecompressedSize);
+    memcpy(Buf, &DecompressedSize, sizeof(DecompressedSize));
+    Buf += sizeof(DecompressedSize);
   } else {
     auto Chdr = reinterpret_cast<Elf_Chdr_Impl<ELFT> *>(Buf);
     Chdr->ch_type = ELF::ELFCOMPRESS_ZLIB;