MC/Mach-O/ARM: Start handling some Thumb branches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122547 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index 5c4d6f2..c8fe40e 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -931,6 +931,20 @@
       // Report as 'long', even though that is not quite accurate.
       Log2Size = llvm::Log2_32(4);
       return true;
+
+      // Handle Thumb branches.
+    case ARM::fixup_arm_thumb_br:
+      Log2Size = llvm::Log2_32(2);
+      return true;
+
+    case ARM::fixup_arm_thumb_bl:
+      Log2Size = llvm::Log2_32(4);
+      return true;
+
+    case ARM::fixup_arm_thumb_blx:
+      // Report as 'long', even though that is not quite accurate.
+      Log2Size = llvm::Log2_32(4);
+      return true;
     }
   }
   void RecordARMRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,