Index: ELF/Arch/RISCV.cpp
===================================================================
--- ELF/Arch/RISCV.cpp
+++ ELF/Arch/RISCV.cpp
@@ -45,7 +45,6 @@
   NoneRel = R_RISCV_NONE;
   CopyRel = R_RISCV_COPY;
   RelativeRel = R_RISCV_RELATIVE;
-  GotRel = Config->Is64 ? R_RISCV_64 : R_RISCV_32;
   PltRel = R_RISCV_JUMP_SLOT;
   GotEntrySize = Config->Wordsize;
   GotPltEntrySize = Config->Wordsize;
@@ -53,6 +52,17 @@
   PltHeaderSize = 32;
   GotPltHeaderEntriesNum = 2;
   GotBaseSymInGotPlt = false;
+  if (Config->Is64) {
+    GotRel = R_RISCV_64;
+    TlsGotRel = R_RISCV_TLS_TPREL64;
+    TlsModuleIndexRel = R_RISCV_TLS_DTPMOD64;
+    TlsOffsetRel = R_RISCV_TLS_DTPREL64;
+  } else {
+    GotRel = R_RISCV_32;
+    TlsGotRel = R_RISCV_TLS_TPREL32;
+    TlsModuleIndexRel = R_RISCV_TLS_DTPMOD32;
+    TlsOffsetRel = R_RISCV_TLS_DTPREL32;
+  }
 }
 
 static uint32_t getEFlags(InputFile *F) {
@@ -179,9 +189,17 @@
   case R_RISCV_PCREL_LO12_S:
     return R_RISCV_PC_INDIRECT;
   case R_RISCV_GOT_HI20:
+  case R_RISCV_TLS_GOT_HI20:
     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_TLS_GD_HI20:
+    return R_TLSGD_PC;
   case R_RISCV_ALIGN:
   case R_RISCV_RELAX:
+  case R_RISCV_TPREL_ADD:
     return R_HINT;
   default:
     return R_ABS;
@@ -294,7 +312,10 @@
   }
 
   case R_RISCV_PCREL_HI20:
+  case R_RISCV_TPREL_HI20:
   case R_RISCV_GOT_HI20:
+  case R_RISCV_TLS_GOT_HI20:
+  case R_RISCV_TLS_GD_HI20:
   case R_RISCV_HI20: {
     uint64_t Hi = Val + 0x800;
     checkInt(Loc, SignExtend64(Hi, Bits) >> 12, 20, Type);
@@ -303,6 +324,7 @@
   }
 
   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);
@@ -311,6 +333,7 @@
   }
 
   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);
@@ -320,6 +343,29 @@
     return;
   }
 
+  case R_RISCV_TLS_DTPMOD32:
+    write32le(Loc, 1);
+    return;
+  case R_RISCV_TLS_DTPMOD64:
+    write64le(Loc, 1);
+    return;
+  case R_RISCV_TLS_DTPREL32:
+    // The pointer in dynamic thread vector (DTV) points to 0x800 past the
+    // TLS block.
+    write32le(Loc, Val - 0x800);
+    return;
+  case R_RISCV_TLS_DTPREL64:
+    write64le(Loc, Val - 0x800);
+    return;
+  case R_RISCV_TLS_TPREL32:
+    write32le(Loc, Val);
+    return;
+  case R_RISCV_TLS_TPREL64:
+    write64le(Loc, Val);
+    return;
+  case R_RISCV_TPREL_ADD:
+    return; // Do nothing
+
   case R_RISCV_ADD8:
     *Loc += Val;
     return;
Index: ELF/InputSection.cpp
===================================================================
--- ELF/InputSection.cpp
+++ ELF/InputSection.cpp
@@ -571,7 +571,8 @@
                        });
 
   for (auto It = Range.first; It != Range.second; ++It)
-    if (It->Expr == R_PC || It->Expr == R_PLT_PC || It->Expr == R_GOT_PC)
+    if (It->Expr == R_PC || It->Expr == R_PLT_PC || It->Expr == R_GOT_PC ||
+        It->Expr == R_TLSGD_PC)
       return &*It;
 
   error("R_RISCV_PCREL_LO12 relocation points to " + IS->getObjMsg(D->Value) +
@@ -603,6 +604,9 @@
     // offset to reach 0x1000 of TCB/thread-library data and 0xf000 of the
     // program's TLS segment.
     return -0x7000;
+  case EM_RISCV:
+    // RISC-V's tp points to the start of the executable's TLS segment.
+    return 0;
   default:
     llvm_unreachable("unhandled Config->EMachine");
   }
Index: ELF/Relocations.cpp
===================================================================
--- ELF/Relocations.cpp
+++ ELF/Relocations.cpp
@@ -212,7 +212,9 @@
   if (!Sym.isTls())
     return 0;
 
-  if (Config->EMachine == EM_ARM)
+  // TODO: RISC-V currently doesn't implement TLS relaxation yet, so we reuse
+  // the same logic for ARM tls relocation.
+  if (Config->EMachine == EM_ARM || Config->EMachine == EM_RISCV)
     return handleARMTlsRelocation(Type, Sym, C, Offset, Addend, Expr);
   if (Config->EMachine == EM_MIPS)
     return handleMipsTlsRelocation(Type, Sym, C, Offset, Addend, Expr);
Index: test/ELF/Inputs/riscv-tls.s
===================================================================
--- /dev/null
+++ test/ELF/Inputs/riscv-tls.s
@@ -0,0 +1,10 @@
+.global __tls_get_addr
+.type   __tls_get_addr, @function
+__tls_get_addr:
+
+.section .tdata, "awT", @progbits
+.global tx
+.type   tx, @object
+.size   tx, 4
+tx:
+    .word 42
Index: test/ELF/riscv-tls-gd.s
===================================================================
--- /dev/null
+++ test/ELF/riscv-tls-gd.s
@@ -0,0 +1,59 @@
+# REQUIRES: riscv
+
+# RUN: llvm-mc -filetype=obj -triple=riscv32-unknown-elf -mattr=-relax -position-independent %s -o %t.rv32.o
+# RUN: llvm-mc -filetype=obj -triple=riscv32-unknown-elf -mattr=-relax -position-independent %p/Inputs/riscv-tls.s -o %t.shared.rv32.o
+# RUN: ld.lld -shared %t.shared.rv32.o -o %t.shared.rv32.so
+# RUN: ld.lld %t.rv32.o %t.shared.rv32.so -o %t.rv32
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64-unknown-elf -mattr=-relax -position-independent %s -o %t.rv64.o
+# RUN: llvm-mc -filetype=obj -triple=riscv64-unknown-elf -mattr=-relax -position-independent %p/Inputs/riscv-tls.s -o %t.shared.rv64.o
+# RUN: ld.lld -shared %t.shared.rv64.o -o %t.shared.rv64.so
+# RUN: ld.lld %t.rv64.o %t.shared.rv64.so -o %t.rv64
+
+# RUN: llvm-readobj -dyn-relocations -dyn-symbols %t.rv32 | FileCheck -DXLEN=32 -DTPMOD=0x12064 -DTPREL=0x12068 %s
+# RUN: llvm-readobj -dyn-relocations -dyn-symbols %t.rv64 | FileCheck -DXLEN=64 -DTPMOD=0x120C8 -DTPREL=0x120D0 %s
+# CHECK:      Dynamic Relocations {
+# CHECK-NEXT:   [[TPMOD]] R_RISCV_TLS_DTPMOD[[XLEN]] tx 0x0
+# CHECK-NEXT:   [[TPREL]] R_RISCV_TLS_DTPREL[[XLEN]] tx 0x0
+# CHECK-NEXT: }
+
+# CHECK:     DynamicSymbols [
+# CHECK:       Name: tx
+# CHECK-NOT:   Name: ty
+
+# RUN: llvm-objdump -d %t.rv32 | FileCheck --check-prefix=DIS32 %s
+# _start = 0x11000, tx = 0x12064, ty = 0x1206c
+# DIS32:      _start:
+# DIS32-NEXT: auipc   a0, 1
+# DIS32-NEXT: addi    a0, a0, 100
+# DIS32:      auipc   a1, 1
+# DIS32-NEXT: addi    a1, a1, 100
+
+# RUN: llvm-objdump -d %t.rv64 | FileCheck --check-prefix=DIS64 %s
+# _start = 0x11000, tx = 0x120c8, ty = 0x120d8
+# DIS64:      _start:
+# DIS64-NEXT: auipc   a0, 1
+# DIS64-NEXT: addi    a0, a0, 200
+# DIS64:      auipc   a1, 1
+# DIS64-NEXT: addi    a1, a1, 208
+
+# RUN: llvm-objdump -s -j.got %t.rv32 | FileCheck --check-prefix=GOT32 %s
+# GOT32:      Contents of section .got:
+# GOT32-NEXT:  12064 00000000 00000000 01000000 00f8ffff
+
+# RUN: llvm-objdump -s -j.got %t.rv64 | FileCheck --check-prefix=GOT64 %s
+# GOT64:      Contents of section .got:
+# GOT64-NEXT:  120c8 00000000 00000000 00000000 00000000
+# GOT64-NEXT:  120d8 01000000 00000000 00f8ffff ffffffff
+
+.global _start
+_start:
+L1:
+    la.tls.gd   a0, tx
+    la.tls.gd   a1, ty
+
+.section .tdata, "awT", @progbits
+.type ty, @object
+.size ty, 4
+ty:
+  .word 42
Index: test/ELF/riscv-tls-ie.s
===================================================================
--- /dev/null
+++ test/ELF/riscv-tls-ie.s
@@ -0,0 +1,56 @@
+# REQUIRES: riscv
+
+# RUN: llvm-mc -filetype=obj -triple=riscv32-unknown-elf -mattr=-relax -position-independent %s -o %t.rv32.o
+# RUN: llvm-mc -filetype=obj -triple=riscv32-unknown-elf -mattr=-relax -position-independent %p/Inputs/riscv-tls.s -o %t.shared.rv32.o
+# RUN: ld.lld -shared %t.shared.rv32.o -o %t.shared.rv32.so
+# RUN: ld.lld %t.rv32.o %t.shared.rv32.so -o %t.rv32
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64-unknown-elf -mattr=-relax -position-independent %s -o %t.rv64.o
+# RUN: llvm-mc -filetype=obj -triple=riscv64-unknown-elf -mattr=-relax -position-independent %p/Inputs/riscv-tls.s -o %t.shared.rv64.o
+# RUN: ld.lld -shared %t.shared.rv64.o -o %t.shared.rv64.so
+# RUN: ld.lld %t.rv64.o %t.shared.rv64.so -o %t.rv64
+
+# RUN: llvm-readobj -dyn-relocations -dyn-symbols %t.rv32 | FileCheck -DXLEN=32 -DGOT=0x12064 %s
+# RUN: llvm-readobj -dyn-relocations -dyn-symbols %t.rv64 | FileCheck -DXLEN=64 -DGOT=0x120C8 %s
+# CHECK:      Dynamic Relocations {
+# CHECK-NEXT:   [[GOT]] R_RISCV_TLS_TPREL[[XLEN]] tx 0x0
+# CHECK-NEXT: }
+
+# CHECK:     DynamicSymbols [
+# CHECK:       Name: tx
+# CHECK-NOT:   Name: ty
+
+# RUN: llvm-objdump -d %t.rv32 | FileCheck --check-prefix=DIS32 %s
+# _start = 0x11000, tx = 0x12064, ty = 0x12068
+# DIS32:      _start:
+# DIS32-NEXT: auipc   a0, 1
+# DIS32-NEXT: lw      a0, 100(a0)
+# DIS32:      auipc   a1, 1
+# DIS32-NEXT: lw      a1, 96(a1)
+
+# RUN: llvm-objdump -d %t.rv64 | FileCheck --check-prefix=DIS64 %s
+# _start = 0x11000, tx = 0x120c8, ty = 0x120d0
+# DIS64:      _start:
+# DIS64-NEXT: auipc   a0, 1
+# DIS64-NEXT: ld      a0, 200(a0)
+# DIS64:      auipc   a1, 1
+# DIS64-NEXT: ld      a1, 200(a1)
+
+# RUN: llvm-objdump -s -j.got %t.rv32 | FileCheck --check-prefix=GOT32 %s
+# GOT32:      Contents of section .got:
+# GOT32-NEXT:  12064 00000000 00000000
+
+# RUN: llvm-objdump -s -j.got %t.rv64 | FileCheck --check-prefix=GOT64 %s
+# GOT64:      Contents of section .got:
+# GOT64-NEXT:  120c8 00000000 00000000 00000000 00000000
+
+.global _start
+_start:
+    la.tls.ie   a0, tx
+    la.tls.ie   a1, ty
+
+.section .tdata, "awT", @progbits
+.type ty, @object
+.size ty, 4
+ty:
+  .word 42
Index: test/ELF/riscv-tls-le.s
===================================================================
--- /dev/null
+++ test/ELF/riscv-tls-le.s
@@ -0,0 +1,43 @@
+# REQUIRES: riscv
+
+# RUN: llvm-mc -filetype=obj -triple=riscv32-unknown-elf -mattr=-relax %s -o %t.rv32.o
+# RUN: ld.lld %t.rv32.o -o %t.rv32
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64-unknown-elf -mattr=-relax %s -o %t.rv64.o
+# RUN: ld.lld %t.rv64.o -o %t.rv64
+
+# RUN: llvm-objdump -d %t.rv32 | FileCheck --check-prefix=DIS %s
+# RUN: llvm-objdump -d %t.rv64 | FileCheck --check-prefix=DIS %s
+# x = tp+0, y = tp+4
+# DIS:      lui     a0, 0
+# DIS-NEXT: add     a0, a0, tp
+# DIS-NEXT: lw      a0, 0(a0)
+# DIS-NEXT: lui     a1, 0
+# DIS-NEXT: add     a1, a1, tp
+# DIS-NEXT: lw      a1, 4(a1)
+
+# RUN: llvm-objdump -s -j.tdata %t.rv32 | FileCheck --check-prefix=TDATA %s
+# RUN: llvm-objdump -s -j.tdata %t.rv64 | FileCheck --check-prefix=TDATA %s
+# TDATA:      Contents of section .tdata:
+# TDATA-NEXT:  {{[0-9a-f]+}} 2a000000
+
+.global _start
+_start:
+  lui a0, %tprel_hi(x)
+  add a0, a0, tp, %tprel_add(x)
+  lw  a0, %tprel_lo(x)(a0)
+  lui a1, %tprel_hi(y)
+  add a1, a1, tp, %tprel_add(y)
+  lw  a1, %tprel_lo(y)(a1)
+
+.section .tdata, "awT", @progbits
+.type x, @object
+.size x, 4
+x:
+  .word 42
+
+.section .tbss, "awT", @nobits
+.type y, @object
+.size y, 4
+y:
+  .zero 4