Debug Info: according to DWARF 2, FORM_ref_addr the same size as an address on
the target system.

It was hard-coded to 4 bytes before. I can't get llvm to generate a
ref_addr on a reasonably sized testing case.

rdar://problem/13559431


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178722 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d3cb4f9..b6b0bb1 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1791,7 +1791,14 @@
         DwarfUnits &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
         Addr += Holder.getCUOffset(Origin->getCompileUnit());
       }
-      Asm->EmitInt32(Addr);
+      // DWARF4: References that use the attribute form DW_FORM_ref_addr are
+      // specified to be four bytes in the DWARF 32-bit format and eight bytes
+      // in the DWARF 64-bit format, while DWARF Version 2 specifies that such
+      // references have the same size as an address on the target system.
+      // Our current version is version 2.
+      Asm->OutStreamer.EmitIntValue(Addr,
+          Form == dwarf::DW_FORM_ref_addr ?
+          Asm->getDataLayout().getPointerSize() : 4);
       break;
     }
     case dwarf::DW_AT_ranges: {