Pull in r277331 from upstream llvm trunk (by Diana Picus):

[AArch64] Return the correct size for TLSDESC_CALLSEQ

  The branch relaxation pass is computing the wrong offsets because it assumes
  TLSDESC_CALLSEQ eats up 4 bytes, when in fact it is lowered to an instruction
  sequence taking up 16 bytes. This can become a problem in huge files with lots
  of TLS accesses, as it may slowly move branch targets out of the range computed
  by the branch relaxation pass.

  Fixes PR24234 https://llvm.org/bugs/show_bug.cgi?id=24234

  Differential Revision: https://reviews.llvm.org/D22870

This fixes "error in backend: fixup value out of range" when compiling
the misc/talkfilters port for AArch64.

Reported by:	sbruno
PR:		201762
MFC after:	3 days

contrib/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp

@@ -52,6 +52,9 @@ unsigned AArch64InstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const {
   case TargetOpcode::IMPLICIT_DEF:
   case TargetOpcode::KILL:
     return 0;
+  case AArch64::TLSDESC_CALLSEQ:
+    // This gets lowered to an instruction sequence which takes 16 bytes
+    return 16;
   }
 
   llvm_unreachable("GetInstSizeInBytes()- Unable to determin insn size");