From 4747d6b0a50fe9fd22c03d10d72a748bef3edb58 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Thu, 30 Jan 2014 04:02:38 +0000
Subject: [PATCH] ARM: support TLS descriptor relocations

Add support for tlsdesc relocations which are part of the ABI, marked as
experimental.  These relocations permit the linker to perform TLS reference
optimizations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200447 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/MC/MCExpr.h                           | 1 +
 lib/MC/MCExpr.cpp                                  | 3 +++
 lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp | 3 +++
 test/MC/ARM/symbol-variants.s                      | 6 ++++++
 4 files changed, 13 insertions(+)

diff --git a/include/llvm/MC/MCExpr.h b/include/llvm/MC/MCExpr.h
index b62252057f9..13f3ad0570b 100644
--- a/include/llvm/MC/MCExpr.h
+++ b/include/llvm/MC/MCExpr.h
@@ -167,6 +167,7 @@ public:
     VK_ARM_PREL31,
     VK_ARM_TLSLDO,         // symbol(tlsldo)
     VK_ARM_TLSCALL,        // symbol(tlscall)
+    VK_ARM_TLSDESC,        // symbol(tlsdesc)
 
     VK_PPC_LO,             // symbol@l
     VK_PPC_HI,             // symbol@h
diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
index 3772bceea57..d402e6d896b 100644
--- a/lib/MC/MCExpr.cpp
+++ b/lib/MC/MCExpr.cpp
@@ -186,6 +186,7 @@ StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
   case VK_ARM_PREL31: return "prel31";
   case VK_ARM_TLSLDO: return "tlsldo";
   case VK_ARM_TLSCALL: return "tlscall";
+  case VK_ARM_TLSDESC: return "tlsdesc";
   case VK_PPC_LO: return "l";
   case VK_PPC_HI: return "h";
   case VK_PPC_HA: return "ha";
@@ -411,6 +412,8 @@ MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
     .Case("tlsldo", VK_ARM_TLSLDO)
     .Case("TLSCALL", VK_ARM_TLSCALL)
     .Case("tlscall", VK_ARM_TLSCALL)
+    .Case("TLSDESC", VK_ARM_TLSDESC)
+    .Case("tlsdesc", VK_ARM_TLSDESC)
     .Default(VK_Invalid);
 }
 
diff --git a/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp b/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
index 08c040235fd..5f719d5bb7c 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
@@ -266,6 +266,9 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
       case MCSymbolRefExpr::VK_ARM_TLSCALL:
         Type = ELF::R_ARM_TLS_CALL;
         break;
+      case MCSymbolRefExpr::VK_ARM_TLSDESC:
+        Type = ELF::R_ARM_TLS_GOTDESC;
+        break;
       }
       break;
     case ARM::fixup_arm_ldst_pcrel_12:
diff --git a/test/MC/ARM/symbol-variants.s b/test/MC/ARM/symbol-variants.s
index f0bf4c4b7c0..cf3535eafa4 100644
--- a/test/MC/ARM/symbol-variants.s
+++ b/test/MC/ARM/symbol-variants.s
@@ -77,3 +77,9 @@ bl f05(plt)
 @ CHECK: 88 R_ARM_TLS_CALL f22
 @ CHECK: 92 R_ARM_TLS_CALL f23
 
+@ tlsdesc
+.word f24(TLSDESC)
+.word f25(tlsdesc)
+@ CHECK: 96 R_ARM_TLS_GOTDESC f24
+@ CHECK: 100 R_ARM_TLS_GOTDESC f25
+