Move some ARM specific MCAssmebler bits into the ARMAsmBackend.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148364 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 1cb97ce..e3cfae8 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -273,13 +273,10 @@
 
   Value = Target.getConstant();
 
-  bool IsThumb = false;
   if (const MCSymbolRefExpr *A = Target.getSymA()) {
     const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
     if (Sym.isDefined())
       Value += Layout.getSymbolOffset(&getSymbolData(Sym));
-    if (isThumbFunc(&Sym))
-      IsThumb = true;
   }
   if (const MCSymbolRefExpr *B = Target.getSymB()) {
     const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
@@ -302,12 +299,8 @@
     Value -= Offset;
   }
 
-  // ARM fixups based from a thumb function address need to have the low
-  // bit set. The actual value is always at least 16-bit aligned, so the
-  // low bit is normally clear and available for use as an ISA flag for
-  // interworking.
-  if (IsThumb)
-    Value |= 1;
+  // Let the backend adjust the fixup value if necessary.
+  Backend.processFixupValue(*this, Layout, Fixup, DF, Target, Value);
 
   return IsResolved;
 }