Model :upper16: and :lower16: as ARM specific MCTargetExpr. This is a step

in the right direction. It eliminated some hacks and will unblock codegen
work. But it's far from being done. It doesn't reject illegal expressions,
e.g. (FOO - :lower16:BAR). It also doesn't work in Thumb2 mode at all.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123369 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCObjectStreamer.cpp

@@ -56,7 +56,10 @@ MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
 
 const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
   switch (Value->getKind()) {
-  case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!");
+  case MCExpr::Target:
+    cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
+    break;
+
   case MCExpr::Constant:
     break;