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

[probinson]

Summary

Previously we had only Linux using DTPOFF for these; all X86 ELF targets should.

[echristo]

Seems like some overkill on the indirection, but you've said you have some more coming for ps4 so OK.

-eric

[emaste]

Could also add:

; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-freebsd \
; RUN:   | FileCheck --check-prefix=CHECK --check-prefix=SINGLE --check-prefix=SINGLE-64 %s

[probinson]

I was wondering about FreeBSD, glad to know it's correct. I added the extra RUN line, will commit shortly.

lib/Target/X86/X86TargetMachine.cpp

if (TT.isOSBinFormatMachO()) {
     if (TT.getArch() == Triple::x86_64)
       return make_unique<X86_64MachoTargetObjectFile>();
     return make_unique<TargetLoweringObjectFileMachO>();
   }
 
   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())
     return make_unique<TargetLoweringObjectFileCOFF>();
   llvm_unreachable("unknown subtarget type");
 }
 
 static std::string computeDataLayout(const Triple &TT) {

lib/Target/X86/X86TargetObjectFile.h

MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV, Mangler &Mang,
                                       const TargetMachine &TM,
                                       MachineModuleInfo *MMI) const override;
 
     const MCExpr *
       getIndirectSymViaGOTPCRel(const MCSymbol *Sym,
                                 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.
   class X86WindowsTargetObjectFile : public TargetLoweringObjectFileCOFF {
     const MCExpr *
     getExecutableRelativeSymbol(const ConstantExpr *CE, Mangler &Mang,
                                 const TargetMachine &TM) const override;
 

lib/Target/X86/X86TargetObjectFile.cpp

const MCExpr *X86_64MachoTargetObjectFile::getIndirectSymViaGOTPCRel(
   // from a data section. In case there's an additional offset, then use
   // foo@GOTPCREL+4+<offset>.
   const MCExpr *Res =
     MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext());
   const MCExpr *Off = MCConstantExpr::Create(Offset+4, getContext());
   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
   // operation.
   const SubOperator *Sub = dyn_cast<SubOperator>(CE);
   if (!Sub)
     return nullptr;
 

test/DebugInfo/X86/tls.ll

 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-linux-gnu \
 ; RUN:   | FileCheck --check-prefix=CHECK --check-prefix=SINGLE --check-prefix=SINGLE-64 %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=i386-linux-gnu \
 ; RUN:   | FileCheck --check-prefix=CHECK --check-prefix=SINGLE --check-prefix=SINGLE-32 %s
 
 ; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-linux-gnu -split-dwarf=Enable \
 ; RUN:   | FileCheck --check-prefix=CHECK --check-prefix=FISSION %s
 
+; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-scei-ps4 \
+; RUN:   | FileCheck --check-prefix=CHECK --check-prefix=SINGLE --check-prefix=SINGLE-64 %s
+
 ; FIXME: add relocation and DWARF expression support to llvm-dwarfdump & use
 ; that here instead of raw assembly printing
 
 ; FISSION: .section    .debug_info.dwo,
 ; 3 bytes of data in this DW_FORM_block1 representation of the location of 'tls'
 ; FISSION: .byte 3{{ *}}# DW_AT_location
 ; DW_OP_GNU_const_index (0xfx == 252) to refer to the debug_addr table
 ; FISSION-NEXT: .byte 252