[X86][ELF] Correct relocation for DWARF TLS references

Previously we had only Linux using DTPOFF for these; all X86 ELF
targets should. Fixes a side issue mentioned in PR21077.

Differential Revision: http://reviews.llvm.org/D8011

llvm-svn: 231130

3 files changed, 14 insertions, 11 deletions

diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index 4bde05306ce..aae0261f65b 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -40,7 +40,7 @@ static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
   if (TT.isOSLinux())
     return make_unique<X86LinuxTargetObjectFile>();
   if (TT.isOSBinFormatELF())
-    return make_unique<TargetLoweringObjectFileELF>();
+    return make_unique<X86ELFTargetObjectFile>();
   if (TT.isKnownWindowsMSVCEnvironment())
     return make_unique<X86WindowsTargetObjectFile>();
   if (TT.isOSBinFormatCOFF())
diff --git a/llvm/lib/Target/X86/X86TargetObjectFile.cpp b/llvm/lib/Target/X86/X86TargetObjectFile.cpp
index 1d1c32eb2cb..678630db966 100644
--- a/llvm/lib/Target/X86/X86TargetObjectFile.cpp
+++ b/llvm/lib/Target/X86/X86TargetObjectFile.cpp
@@ -62,18 +62,17 @@ const MCExpr *X86_64MachoTargetObjectFile::getIndirectSymViaGOTPCRel(
   return MCBinaryExpr::CreateAdd(Res, Off, getContext());
 }
 
+const MCExpr *X86ELFTargetObjectFile::getDebugThreadLocalSymbol(
+    const MCSymbol *Sym) const {
+  return MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_DTPOFF, getContext());
+}
+
 void
 X86LinuxTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM) {
   TargetLoweringObjectFileELF::Initialize(Ctx, TM);
   InitializeELF(TM.Options.UseInitArray);
 }
 
-const MCExpr *
-X86LinuxTargetObjectFile::getDebugThreadLocalSymbol(
-    const MCSymbol *Sym) const {
-  return MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_DTPOFF, getContext());
-}
-
 const MCExpr *X86WindowsTargetObjectFile::getExecutableRelativeSymbol(
     const ConstantExpr *CE, Mangler &Mang, const TargetMachine &TM) const {
   // We are looking for the difference of two symbols, need a subtraction
diff --git a/llvm/lib/Target/X86/X86TargetObjectFile.h b/llvm/lib/Target/X86/X86TargetObjectFile.h
index f7455382098..a92c122838e 100644
--- a/llvm/lib/Target/X86/X86TargetObjectFile.h
+++ b/llvm/lib/Target/X86/X86TargetObjectFile.h
@@ -38,13 +38,17 @@ namespace llvm {
                                 int64_t Offset) const override;
   };
 
+  /// \brief This implemenatation is used for X86 ELF targets that don't
+  /// have a further specialization.
+  class X86ELFTargetObjectFile : public TargetLoweringObjectFileELF {
+    /// \brief Describe a TLS variable address within debug info.
+    const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const override;
+  };
+
   /// X86LinuxTargetObjectFile - This implementation is used for linux x86
   /// and x86-64.
-  class X86LinuxTargetObjectFile : public TargetLoweringObjectFileELF {
+  class X86LinuxTargetObjectFile : public X86ELFTargetObjectFile {
     void Initialize(MCContext &Ctx, const TargetMachine &TM) override;
-
-    /// \brief Describe a TLS variable address within debug info.
-    const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const override;
   };
 
   /// \brief This implementation is used for Windows targets on x86 and x86-64.