[ELF][RISCV] Support GD/LD/IE/LE TLS models

[MaskRay]

Summary

RISC-V psABI doesn't specify TLS relaxation. Though the code sequences
are not relaxed, dynamic relocations DTPMOD/DTPREL can be omitted if the
TLS model can be relaxed to Local-Exec.

[MaskRay]

Support all 4 models

[MaskRay]

Support GD/LD/IE/LE TLS models

[MaskRay]

Delete an unrelated change (moving In.RelaDyn)

[ruiu]

LGTM

[jrtc27]

ELF/Arch/RISCV.cpp

77–87

I think it would be better to fold this into the if.

ELF/Relocations.cpp

171

The RISC-V behaviour is identical to ARM if I remember correctly, so we should be reusing that code rather than reimplementing it again here.

test/ELF/riscv-tls-ld.s

2

This file is the same as GD just with different check prefixes, no? RISC-V’s local dynamic is the same as global dynamic as far as relocations are concerned.

[MaskRay]

ELF/Relocations.cpp

171

R_ARM_TLS_GD32 <-> R_RISCV_TLS_GD_HI20
R_ARM_TLS_LDM32 <-> R_RISCV_TLS_GD_HI20 with a local symbol .LANCHOR0
R_ARM_TLS_IE32 <-> R_RISCV_TLS_GOT_HI20
R_ARM_TLS_LE32 <-> R_RISCV_TPREL_{HI20,LO12_I,LO12_S}

If this is what you mean :)

However, there is a big difference: RISC-V doesn't support relaxation. So I have to make sure no R_RELAX_TLS_* code is called.

Having the two variables is the least intrusive approach I can think of. (I complained the lack of linker relaxation turns out to make lld's generic TLS handling uglier. Here it is :))

test/ELF/riscv-tls-ld.s

2

No exactly the same.

riscv-tls-gd.s checks preemptable symbols. This file checks .LANCHOR0. I do struggle to make the tests simpler while covering useful/possible scenarios.

[MaskRay]

Fold Config->Is64 ? :

[MaskRay]

For the curious. I used the tests to compare the behaviors of lld and ld.bfd and found 2 problems that ld.bfd have :) https://sourceware.org/bugzilla/show_bug.cgi?id=24673 https://sourceware.org/bugzilla/show_bug.cgi?id=24676

I think it is fine to never have GD->IE, GD->LE, LD->LE, if we can get deprecate GD/LD (R_RISCV_TLS_GD_HI20) and migrate to TLSDESC (https://github.com/riscv/riscv-elf-psabi-doc/issues/94). However, IE->LE is still useful. It would be nice if psABI specified that.

[MaskRay]

Add DF_STATIC_TLS
Explain LD references a local symbol

[MaskRay]

ELF/Relocations.cpp

171

Sorry, I think you probably meant we can reuse handleARMTlsRelocation() for RISC-V. I have compared it with handleTlsRelocation() and find it may be worth merging the two functions. Created D63333 for that idea. With that patch, the Relocations.cpp change in this patch will be trivial.

- bool Relax = Config->EMachine != EM_ARM;
+ bool Relax = Config->EMachine != EM_ARM && Config->EMachine != EM_RISCV;

[MaskRay]

Rebase D63333

[jrtc27]

One minor pedantic stylistic comment but otherwise this seems fine to me.

ELF/Arch/RISCV.cpp

345

This order is inconsistent with the LO12_[IS] variants. Personally I'd leave HI20/LO12_* as the final case statement before the block, and put the TLS/TPREL statements between PCREL and the plain HI20/LO12_*. This also has the benefit of reducing churn in the diff by not modifying existing lines unnecessarily.

[MaskRay]

Place HI20/LO12_[IS] at the bottom

ELF/Arch/RISCV.cpp

public:
   RelType getDynRel(RelType Type) const override;
   RelExpr getRelExpr(RelType Type, const Symbol &S,
                      const uint8_t *Loc) const override;
   void relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const override;
 };
 
 } // end anonymous namespace
 
+const uint64_t DTPOffset = 0x800;
+
 enum Op {
   ADDI = 0x13,
   AUIPC = 0x17,
   JALR = 0x67,
   LD = 0x3003,
   LW = 0x2003,
   SRLI = 0x5013,
   SUB = 0x40000033,
static uint32_t utype(uint32_t Op, uint32_t Rd, uint32_t Imm) {
   return Op | (Rd << 7) | (Imm << 12);
 }
 
 RISCV::RISCV() {
   CopyRel = R_RISCV_COPY;
   NoneRel = R_RISCV_NONE;
   PltRel = R_RISCV_JUMP_SLOT;
   RelativeRel = R_RISCV_RELATIVE;
-  SymbolicRel = Config->Is64 ? R_RISCV_64 : R_RISCV_32;
+  if (Config->Is64) {
+    SymbolicRel = R_RISCV_64;
+    TlsModuleIndexRel = R_RISCV_TLS_DTPMOD64;
+    TlsOffsetRel = R_RISCV_TLS_DTPREL64;
+    TlsGotRel = R_RISCV_TLS_TPREL64;
+  } else {
+    SymbolicRel = R_RISCV_32;
+    TlsModuleIndexRel = R_RISCV_TLS_DTPMOD32;
+    TlsOffsetRel = R_RISCV_TLS_DTPREL32;
+    TlsGotRel = R_RISCV_TLS_TPREL32;
+  }
   GotRel = SymbolicRel;
 
   // .got[0] = _DYNAMIC
   GotBaseSymInGotPlt = false;
   GotHeaderEntriesNum = 1;
 
   // .got.plt[0] = _dl_runtime_resolve, .got.plt[1] = link_map
   GotPltHeaderEntriesNum = 2;
RelExpr RISCV::getRelExpr(const RelType Type, const Symbol &S,
   case R_RISCV_CALL:
   case R_RISCV_CALL_PLT:
     return R_PLT_PC;
   case R_RISCV_GOT_HI20:
     return R_GOT_PC;
   case R_RISCV_PCREL_LO12_I:
   case R_RISCV_PCREL_LO12_S:
     return R_RISCV_PC_INDIRECT;
+  case R_RISCV_TLS_GD_HI20:
+    return R_TLSGD_PC;
+  case R_RISCV_TLS_GOT_HI20:
+    Config->HasStaticTlsModel = true;
+    return R_GOT_PC;
+  case R_RISCV_TPREL_HI20:
+  case R_RISCV_TPREL_LO12_I:
+  case R_RISCV_TPREL_LO12_S:
+    return R_TLS;
   case R_RISCV_RELAX:
   case R_RISCV_ALIGN:
+  case R_RISCV_TPREL_ADD:
     return R_HINT;
   default:
     return R_ABS;
   }
 }
 
 // Extract bits V[Begin:End], where range is inclusive, and Begin must be < 63.
 static uint32_t extractBits(uint64_t V, uint32_t Begin, uint32_t End) {
if (isInt<20>(Hi)) {
       relocateOne(Loc, R_RISCV_PCREL_HI20, Val);
       relocateOne(Loc + 4, R_RISCV_PCREL_LO12_I, Val);
     }
     return;
   }
 
   case R_RISCV_GOT_HI20:
   case R_RISCV_PCREL_HI20:
+  case R_RISCV_TLS_GD_HI20:
+  case R_RISCV_TLS_GOT_HI20:
+  case R_RISCV_TPREL_HI20:
   case R_RISCV_HI20: {
     uint64_t Hi = Val + 0x800;
     checkInt(Loc, SignExtend64(Hi, Bits) >> 12, 20, Type);
     write32le(Loc, (read32le(Loc) & 0xFFF) | (Hi & 0xFFFFF000));
     return;
   }
 
   case R_RISCV_PCREL_LO12_I:
+  case R_RISCV_TPREL_LO12_I:
   case R_RISCV_LO12_I: {
     uint64_t Hi = (Val + 0x800) >> 12;
     uint64_t Lo = Val - (Hi << 12);
     write32le(Loc, (read32le(Loc) & 0xFFFFF) | ((Lo & 0xFFF) << 20));
     return;
   }
 
   case R_RISCV_PCREL_LO12_S:
+  case R_RISCV_TPREL_LO12_S:
   case R_RISCV_LO12_S: {
     uint64_t Hi = (Val + 0x800) >> 12;
     uint64_t Lo = Val - (Hi << 12);
     uint32_t Imm11_5 = extractBits(Lo, 11, 5) << 25;
     uint32_t Imm4_0 = extractBits(Lo, 4, 0) << 7;
     write32le(Loc, (read32le(Loc) & 0x1FFF07F) | Imm11_5 | Imm4_0);
     return;
   }
void RISCV::relocateOne(uint8_t *Loc, const RelType Type,
   case R_RISCV_SET16:
     write16le(Loc, Val);
     return;
   case R_RISCV_SET32:
   case R_RISCV_32_PCREL:
     write32le(Loc, Val);
     return;
 
+  case R_RISCV_TLS_DTPREL32:
+    write32le(Loc, Val - DTPOffset);
+    break;
+  case R_RISCV_TLS_DTPREL64:
+    write64le(Loc, Val - DTPOffset);
+    break;
+
   case R_RISCV_ALIGN:
   case R_RISCV_RELAX:
     return; // Ignored (for now)
   case R_RISCV_NONE:
     return; // Do nothing
 
   // These are handled by the dynamic linker
   case R_RISCV_RELATIVE:

ELF/InputSection.cpp

static Relocation *getRISCVPCRelHi20(const Symbol *Sym, uint64_t Addend) {
   R.Offset = D->Value;
   auto Range =
       std::equal_range(IS->Relocations.begin(), IS->Relocations.end(), R,
                        [](const Relocation &LHS, const Relocation &RHS) {
                          return LHS.Offset < RHS.Offset;
                        });
 
   for (auto It = Range.first; It != Range.second; ++It)
-    if (It->Type == R_RISCV_PCREL_HI20 || It->Type == R_RISCV_GOT_HI20)
+    if (It->Type == R_RISCV_PCREL_HI20 || It->Type == R_RISCV_GOT_HI20 ||
+        It->Type == R_RISCV_TLS_GD_HI20 || It->Type == R_RISCV_TLS_GOT_HI20)
       return &*It;
 
   error("R_RISCV_PCREL_LO12 relocation points to " + IS->getObjMsg(D->Value) +
         " without an associated R_RISCV_PCREL_HI20 relocation");
   return nullptr;
 }
 
 // A TLS symbol's virtual address is relative to the TLS segment. Add a
case EM_X86_64:
     return S.getVA(0) - alignTo(Out::TlsPhdr->p_memsz, Out::TlsPhdr->p_align);
   case EM_PPC:
   case EM_PPC64:
     // The thread pointer points to a fixed offset from the start of the
     // executable's TLS segment. An offset of 0x7000 allows a signed 16-bit
     // offset to reach 0x1000 of TCB/thread-library data and 0xf000 of the
     // program's TLS segment.
     return S.getVA(0) - 0x7000;
+  case EM_RISCV:
+    return S.getVA(0);
   default:
     llvm_unreachable("unhandled Config->EMachine");
   }
 }
 
 static uint64_t getRelocTargetVA(const InputFile *File, RelType Type, int64_t A,
                                  uint64_t P, const Symbol &Sym, RelExpr Expr) {
   switch (Expr) {

ELF/Relocations.cpp

handleTlsRelocation(RelType Type, Symbol &Sym, InputSectionBase &C,
 
   if (Config->EMachine == EM_MIPS)
     return handleMipsTlsRelocation(Type, Sym, C, Offset, Addend, Expr);
 
   if (oneof<R_AARCH64_TLSDESC_PAGE, R_TLSDESC, R_TLSDESC_CALL, R_TLSDESC_PC>(
           Expr) &&
       Config->Shared) {
     if (In.Got->addDynTlsEntry(Sym)) {
       uint64_t Off = In.Got->getGlobalDynOffset(Sym);
       Main->RelaDyn->addReloc(
           {Target->TlsDescRel, In.Got, Off, !Sym.IsPreemptible, &Sym, 0});
     }
     if (Expr != R_TLSDESC_CALL)
       C.Relocations.push_back({Expr, Type, Offset, Addend, &Sym});
     return 1;
   }
 
-  bool CanRelax = Config->EMachine != EM_ARM;
+  bool CanRelax = Config->EMachine != EM_ARM && Config->EMachine != EM_RISCV;
 
   // If we are producing an executable and the symbol is non-preemptable, it
   // must be defined and the code sequence can be relaxed to use Local-Exec.
   //
   // ARM and RISC-V do not support any relaxations for TLS relocations, however,
   // we can omit the DTPMOD dynamic relocations and resolve them at link time
   // because them are always 1. This may be necessary for static linking as
   // DTPMOD may not be expected at load time.

test/ELF/riscv-tls-gd.s

+# REQUIRES: riscv
+# RUN: echo '.tbss; .globl b, c; b: .zero 4; c:' > %t.s
+# RUN: echo '.globl __tls_get_addr; __tls_get_addr:' > %tga.s
+
+## RISC-V psABI doesn't specify TLS relaxation. Though the code sequences are not
+## relaxed, dynamic relocations can be omitted for GD->LE relaxation.
+
+# RUN: llvm-mc -filetype=obj -triple=riscv32 %s -o %t.32.o
+# RUN: llvm-mc -filetype=obj -triple=riscv32 %t.s -o %t1.32.o
+# RUN: ld.lld -shared -soname=t1.so %t1.32.o -o %t1.32.so
+# RUN: llvm-mc -filetype=obj -triple=riscv32 %tga.s -o %tga.32.o
+## rv32 GD
+# RUN: ld.lld -shared %t.32.o %t1.32.o -o %t.32.so
+# RUN: llvm-readobj -r %t.32.so | FileCheck --check-prefix=GD32-REL %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.32.so | FileCheck --check-prefix=GD32 %s
+## rv32 GD -> LE
+# RUN: ld.lld %t.32.o %t1.32.o %tga.32.o -o %t.32
+# RUN: llvm-readelf -r %t.32 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.32 | FileCheck --check-prefix=LE32-GOT %s
+# RUN: ld.lld -pie %t.32.o %t1.32.o %tga.32.o -o %t.32
+# RUN: llvm-readelf -r %t.32 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.32 | FileCheck --check-prefix=LE32-GOT %s
+## rv32 GD -> IE
+# RUN: ld.lld %t.32.o %t1.32.so %tga.32.o -o %t.32
+# RUN: llvm-readobj -r %t.32 | FileCheck --check-prefix=IE32-REL %s
+# RUN: llvm-readelf -x .got %t.32 | FileCheck --check-prefix=IE32-GOT %s
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 %s -o %t.64.o
+# RUN: llvm-mc -filetype=obj -triple=riscv64 %t.s -o %t1.64.o
+# RUN: ld.lld -shared -soname=t1.so %t1.64.o -o %t1.64.so
+# RUN: llvm-mc -filetype=obj -triple=riscv64 %tga.s -o %tga.64.o
+## rv64 GD
+# RUN: ld.lld -shared %t.64.o %t1.64.o -o %t.64.so
+# RUN: llvm-readobj -r %t.64.so | FileCheck --check-prefix=GD64-REL %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64.so | FileCheck --check-prefix=GD64 %s
+## rv64 GD -> LE
+# RUN: ld.lld %t.64.o %t1.64.o %tga.64.o -o %t.64
+# RUN: llvm-readelf -r %t.64 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.64 | FileCheck --check-prefix=LE64-GOT %s
+# RUN: ld.lld -pie %t.64.o %t1.64.o %tga.64.o -o %t.64
+# RUN: llvm-readelf -r %t.64 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.64 | FileCheck --check-prefix=LE64-GOT %s
+## rv64 GD -> IE
+# RUN: ld.lld %t.64.o %t1.64.so %tga.64.o -o %t.64
+# RUN: llvm-readobj -r %t.64 | FileCheck --check-prefix=IE64-REL %s
+# RUN: llvm-readelf -x .got %t.64 | FileCheck --check-prefix=IE64-GOT %s
+
+# GD32-REL:      .rela.dyn {
+# GD32-REL-NEXT:   0x2070 R_RISCV_TLS_DTPMOD32 a 0x0
+# GD32-REL-NEXT:   0x2074 R_RISCV_TLS_DTPREL32 a 0x0
+# GD32-REL-NEXT:   0x2078 R_RISCV_TLS_DTPMOD32 b 0x0
+# GD32-REL-NEXT:   0x207C R_RISCV_TLS_DTPREL32 b 0x0
+# GD32-REL-NEXT: }
+
+## &DTPMOD(a) - . = 0x2070 - 0x1000 = 4096*1+112
+# GD32:      1000: auipc a0, 1
+# GD32-NEXT:       addi a0, a0, 112
+# GD32-NEXT:       auipc ra, 0
+# GD32-NEXT:       jalr ra, ra, 56
+
+## &DTPMOD(b) - . = 0x2078 - 0x1010 = 4096*1+104
+# GD32:      1010: auipc a0, 1
+# GD32-NEXT:       addi a0, a0, 104
+# GD32-NEXT:       auipc ra, 0
+# GD32-NEXT:       jalr ra, ra, 40
+
+# GD64-REL:      .rela.dyn {
+# GD64-REL-NEXT:   0x20E0 R_RISCV_TLS_DTPMOD64 a 0x0
+# GD64-REL-NEXT:   0x20E8 R_RISCV_TLS_DTPREL64 a 0x0
+# GD64-REL-NEXT:   0x20F0 R_RISCV_TLS_DTPMOD64 b 0x0
+# GD64-REL-NEXT:   0x20F8 R_RISCV_TLS_DTPREL64 b 0x0
+# GD64-REL-NEXT: }
+
+## &DTPMOD(a) - . = 0x20e0 - 0x1000 = 4096*1+224
+# GD64:      1000: auipc a0, 1
+# GD64-NEXT:       addi a0, a0, 224
+# GD64-NEXT:       auipc ra, 0
+# GD64-NEXT:       jalr ra, ra, 56
+
+## &DTPMOD(b) - . = 0x20f0 - 0x1010 = 4096*1+224
+# GD64:      1010: auipc a0, 1
+# GD64-NEXT:       addi a0, a0, 224
+# GD64-NEXT:       auipc ra, 0
+# GD64-NEXT:       jalr ra, ra, 40
+
+# NOREL: no relocations
+
+## .got contains pre-populated values: [a@dtpmod, a@dtprel, b@dtpmod, b@dtprel]
+## a@dtprel = st_value(a)-0x800 = 0xfffff808
+## b@dtprel = st_value(b)-0x800 = 0xfffff80c
+# LE32-GOT: section '.got':
+# LE32-GOT-NEXT: 0x{{[0-9a-f]+}} 01000000 08f8ffff 01000000 0cf8ffff
+# LE64-GOT: section '.got':
+# LE64-GOT-NEXT: 0x{{[0-9a-f]+}} 01000000 00000000 08f8ffff ffffffff
+# LE64-GOT-NEXT: 0x{{[0-9a-f]+}} 01000000 00000000 0cf8ffff ffffffff
+
+## a is local - relaxed to LE - its DTPMOD/DTPREL slots are link-time constants.
+## b is external - DTPMOD/DTPREL dynamic relocations are required.
+# IE32-REL:      .rela.dyn {
+# IE32-REL-NEXT:   0x12068 R_RISCV_TLS_DTPMOD32 b 0x0
+# IE32-REL-NEXT:   0x1206C R_RISCV_TLS_DTPREL32 b 0x0
+# IE32-REL-NEXT: }
+# IE32-GOT:      section '.got':
+# IE32-GOT-NEXT: 0x00012060 01000000 08f8ffff 00000000 00000000
+
+# IE64-REL:      .rela.dyn {
+# IE64-REL-NEXT:   0x120D0 R_RISCV_TLS_DTPMOD64 b 0x0
+# IE64-REL-NEXT:   0x120D8 R_RISCV_TLS_DTPREL64 b 0x0
+# IE64-REL-NEXT: }
+# IE64-GOT:      section '.got':
+# IE64-GOT-NEXT: 0x000120c0 01000000 00000000 08f8ffff ffffffff
+# IE64-GOT-NEXT: 0x000120d0 00000000 00000000 00000000 00000000
+
+la.tls.gd a0,a
+call __tls_get_addr@plt
+
+la.tls.gd a0,b
+call __tls_get_addr@plt
+
+.section .tbss
+.globl a
+.zero 8
+a:
+.zero 4

test/ELF/riscv-tls-ie.s

+# REQUIRES: riscv
+
+# RUN: llvm-mc -filetype=obj -triple=riscv32 %s -o %t.32.o
+## rv32 IE
+# RUN: ld.lld -shared %t.32.o -o %t.32.so
+# RUN: llvm-readobj -r -d %t.32.so | FileCheck --check-prefix=IE32-REL %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.32.so | FileCheck --check-prefixes=IE,IE32 %s
+## rv32 IE -> LE
+# RUN: ld.lld %t.32.o -o %t.32
+# RUN: llvm-readelf -r %t.32 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.32 | FileCheck --check-prefix=LE32-GOT %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.32 | FileCheck --check-prefixes=LE,LE32 %s
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 %s -o %t.64.o
+## rv64 IE
+# RUN: ld.lld -shared %t.64.o -o %t.64.so
+# RUN: llvm-readobj -r -d %t.64.so | FileCheck --check-prefix=IE64-REL %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64.so | FileCheck --check-prefixes=IE,IE64 %s
+## rv64 IE -> LE
+# RUN: ld.lld %t.64.o -o %t.64
+# RUN: llvm-readelf -r %t.64 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.64 | FileCheck --check-prefix=LE64-GOT %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64 | FileCheck --check-prefixes=LE,LE64 %s
+
+# IE32-REL:      .rela.dyn {
+# IE32-REL-NEXT:   0x205C R_RISCV_TLS_TPREL32 - 0xC
+# IE32-REL-NEXT:   0x2058 R_RISCV_TLS_TPREL32 a 0x0
+# IE32-REL-NEXT: }
+# IE32-REL:      FLAGS STATIC_TLS
+
+# IE64-REL:      .rela.dyn {
+# IE64-REL-NEXT:   0x20B8 R_RISCV_TLS_TPREL64 - 0xC
+# IE64-REL-NEXT:   0x20B0 R_RISCV_TLS_TPREL64 a 0x0
+# IE64-REL-NEXT: }
+# IE64-REL:      FLAGS STATIC_TLS
+
+## rv32: &.got[1] - . = 0x2058 - . = 4096*1+88
+## rv64: &.got[1] - . = 0x20B0 - . = 4096*1+176
+# IE:        1000: auipc a4, 1
+# IE32-NEXT:       lw a4, 88(a4)
+# IE64-NEXT:       ld a4, 176(a4)
+# IE-NEXT:         add a4, a4, tp
+## rv32: &.got[0] - . = 0x205C - . = 4096*1+80
+## rv64: &.got[0] - . = 0x20B8 - . = 4096*1+172
+# IE:        100c: auipc a5, 1
+# IE32-NEXT:       lw a5, 80(a5)
+# IE64-NEXT:       ld a5, 172(a5)
+# IE-NEXT:         add a5, a5, tp
+
+# NOREL: no relocations
+
+# a@tprel = st_value(a) = 0x8
+# b@tprel = st_value(a) = 0xc
+# LE32-GOT: section '.got':
+# LE32-GOT-NEXT: 0x00012000 08000000 0c000000
+# LE64-GOT: section '.got':
+# LE64-GOT-NEXT: 0x00012000 08000000 00000000 0c000000 00000000
+
+## rv32: &.got[0] - . = 0x12000 - 0x11000 = 4096*1+0
+## rv64: &.got[0] - . = 0x12000 - 0x11000 = 4096*1+0
+# LE:        11000: auipc a4, 1
+# LE32-NEXT:        lw a4, 0(a4)
+# LE64-NEXT:        ld a4, 0(a4)
+# LE-NEXT:          add a4, a4, tp
+## rv32: &.got[1] - . = 0x12004 - 0x1100c = 4096*1-8
+## rv64: &.got[1] - . = 0x12008 - 0x1100c = 4096*1-4
+# LE:        1100c: auipc a5, 1
+# LE32-NEXT:        lw a5, -8(a5)
+# LE64-NEXT:        ld a5, -4(a5)
+# LE-NEXT:          add a5, a5, tp
+
+la.tls.ie a4,a
+add a4,a4,tp
+la.tls.ie a5,b
+add a5,a5,tp
+
+.section .tbss
+.globl a
+.zero 8
+a:
+.zero 4
+b:

test/ELF/riscv-tls-ld.s

+# REQUIRES: riscv
+# RUN: echo '.tbss; .globl b, c; b: .zero 4; c:' > %t.s
+# RUN: echo '.globl __tls_get_addr; __tls_get_addr:' > %tga.s
+
+## RISC-V psABI doesn't specify TLS relaxation. Though the code sequences are not
+## relaxed, dynamic relocations can be omitted for LD->LE relaxation.
+## LD uses the same relocation as GD: R_RISCV_GD_HI20, the difference is that it
+## references a local symbol (.LANCHOR0).
+
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -position-independent %s -o %t.32.o
+# RUN: llvm-mc -filetype=obj -triple=riscv32 %tga.s -o %tga.o
+## rv32 LD
+# RUN: ld.lld -shared %t.32.o -o %t.32.so
+# RUN: llvm-readobj -r %t.32.so | FileCheck --check-prefix=LD32-REL %s
+# RUN: llvm-readelf -x .got %t.32.so | FileCheck --check-prefix=LD32-GOT %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.32.so | FileCheck --check-prefixes=LD,LD32 %s
+## rv32 LD -> LE
+# RUN: ld.lld %t.32.o %tga.o -o %t.32
+# RUN: llvm-readelf -r %t.32 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.32 | FileCheck --check-prefix=LE32-GOT %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.32 | FileCheck --check-prefixes=LE,LE32 %s
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -position-independent %s -o %t.64.o
+# RUN: llvm-mc -filetype=obj -triple=riscv64 %tga.s -o %tga.o
+## rv64 LD
+# RUN: ld.lld -shared %t.64.o -o %t.64.so
+# RUN: llvm-readobj -r %t.64.so | FileCheck --check-prefix=LD64-REL %s
+# RUN: llvm-readelf -x .got %t.64.so | FileCheck --check-prefix=LD64-GOT %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64.so | FileCheck --check-prefixes=LD,LD64 %s
+## rv64 LD -> LE
+# RUN: ld.lld %t.64.o %tga.o -o %t.64
+# RUN: llvm-readelf -r %t.64 | FileCheck --check-prefix=NOREL %s
+# RUN: llvm-readelf -x .got %t.64 | FileCheck --check-prefix=LE64-GOT %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64 | FileCheck --check-prefixes=LE,LE64 %s
+
+## a@dtprel = st_value(a)-0x800 = 0xfffff808 is a link-time constant.
+# LD32-REL:      .rela.dyn {
+# LD32-REL-NEXT:   0x2084
+# LD32-REL-NEXT:   0x207C R_RISCV_TLS_DTPMOD32 - 0x0
+# LD32-REL-NEXT: }
+# LD32-GOT:      section '.got':
+# LD32-GOT-NEXT: 0x00002078 00200000 00000000 00f8ffff 00000000
+
+# LD64-REL:      .rela.dyn {
+# LD64-REL-NEXT:   0x2108
+# LD64-REL-NEXT:   0x20F8 R_RISCV_TLS_DTPMOD64 - 0x0
+# LD64-REL-NEXT: }
+# LD64-GOT:      section '.got':
+# LD64-GOT-NEXT: 0x000020f0 00200000 00000000 00000000 00000000
+# LD64-GOT-NEXT: 0x00002100 00f8ffff ffffffff 00000000 00000000
+
+## rv32: &DTPMOD(a) - . = 0x207c - 0x1000 = 4096*1+124
+## rv64: &DTPMOD(a) - . = 0x20e0 - 0x1000 = 4096*1+248
+# LD:        1000: auipc a0, 1
+# LD32-NEXT:       addi a0, a0, 124
+# LD64-NEXT:       addi a0, a0, 248
+# LD-NEXT:         auipc ra, 0
+# LD-NEXT:         jalr ra, ra, 56
+
+# NOREL: no relocations
+
+## a is local - its DTPMOD/DTPREL slots are link-time constants.
+## a@dtpmod = 1 (main module)
+# LE32-GOT: section '.got':
+# LE32-GOT-NEXT: 0x00012000 00000000 01000000 00f8ffff 00200100
+
+# LE64-GOT: section '.got':
+# LE64-GOT-NEXT: 0x00012000 00000000 00000000 01000000 00000000
+# LE64-GOT-NEXT: 0x00012010 00f8ffff ffffffff 00200100 00000000
+
+## rv32: DTPMOD(.LANCHOR0) - . = 0x12004 - 0x11000 = 4096*1+4
+## rv64: DTPMOD(.LANCHOR0) - . = 0x12008 - 0x11000 = 4096*1+8
+# LE:        11000: auipc a0, 1
+# LE32-NEXT:        addi a0, a0, 4
+# LE64-NEXT:        addi a0, a0, 8
+# LE-NEXT:          auipc ra, 0
+# LE-NEXT:          jalr ra, ra, 24
+
+la.tls.gd a0, .LANCHOR0
+call __tls_get_addr@plt
+lw a4, 0(a0)
+lh a0, 4(a0)
+
+## This is irrelevant to TLS. We use it to take 2 GOT slots to check DTPREL
+## offsets are correct.
+la a5, _GLOBAL_OFFSET_TABLE_
+
+.section .tbss,"awT",@nobits
+.set .LANCHOR0, . + 0
+.zero 8

test/ELF/riscv-tls-le.s

+# REQUIRES: riscv
+
+# RUN: llvm-mc -filetype=obj -triple=riscv32 %s -o %t.32.o
+# RUN: ld.lld %t.32.o -o %t.32
+# RUN: llvm-nm -p %t.32 | FileCheck --check-prefixes=NM %s
+# RUN: llvm-objdump -d --no-show-raw-insn %t.32 | FileCheck --check-prefixes=LE %s
+# RUN: ld.lld -pie %t.32.o -o %t.32
+# RUN: llvm-objdump -d --no-show-raw-insn %t.32 | FileCheck --check-prefixes=LE %s
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 %s -o %t.64.o
+# RUN: ld.lld %t.64.o -o %t.64
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64 | FileCheck --check-prefixes=LE %s
+# RUN: ld.lld -pie %t.64.o -o %t.64
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64 | FileCheck --check-prefixes=LE %s
+
+# NM: {{0*}}00000008 b .LANCHOR0
+# NM: {{0*}}0000000c B a
+
+## .LANCHOR0@tprel = 8
+## a@tprel = 12
+# LE:      lui a5, 0
+# LE-NEXT: add a5, a5, tp
+# LE-NEXT: addi a5, a5, 8
+# LE-NEXT: lui a5, 0
+# LE-NEXT: add a5, a5, tp
+# LE-NEXT: sw a0, 12(a5)
+
+lui a5, %tprel_hi(.LANCHOR0)
+add a5, a5, tp, %tprel_add(.LANCHOR0)
+addi a5, a5, %tprel_lo(.LANCHOR0)
+
+lui a5, %tprel_hi(a)
+add a5, a5, tp, %tprel_add(a)
+sw a0, %tprel_lo(a)(a5)
+
+.section .tbss
+.space 8
+.LANCHOR0:
+.zero 4
+.globl a
+a: