[mips] Fix debug information for __thread variable

This patch fixes debug information for __thread variable on Mips
using .dtprelword and .dtpreldword directives.

Patch by Aleksandar Beserminji.

Differential Revision: http://reviews.llvm.org/D28770

llvm-svn: 292624
diff --git a/llvm/lib/Target/Mips/MipsTargetObjectFile.cpp b/llvm/lib/Target/Mips/MipsTargetObjectFile.cpp
index fadab78..c5d6a05 100644
--- a/llvm/lib/Target/Mips/MipsTargetObjectFile.cpp
+++ b/llvm/lib/Target/Mips/MipsTargetObjectFile.cpp
@@ -148,3 +148,11 @@
   // Otherwise, we work the same as ELF.
   return TargetLoweringObjectFileELF::getSectionForConstant(DL, Kind, C, Align);
 }
+
+const MCExpr *
+MipsTargetObjectFile::getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
+  const MCExpr *Expr =
+      MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, getContext());
+  return MCBinaryExpr::createAdd(
+      Expr, MCConstantExpr::create(0x8000, getContext()), getContext());
+}