diff --git a/lld/wasm/InputChunks.cpp b/lld/wasm/InputChunks.cpp
--- a/lld/wasm/InputChunks.cpp
+++ b/lld/wasm/InputChunks.cpp
@@ -43,6 +43,7 @@
   case R_WASM_TABLE_INDEX_I64:
   case R_WASM_FUNCTION_OFFSET_I64:
   case R_WASM_TABLE_INDEX_REL_SLEB64:
+  case R_WASM_MEMORY_ADDR_TLS_SLEB64:
     return true;
   default:
     return false;
@@ -140,6 +141,7 @@
     case R_WASM_TABLE_INDEX_REL_SLEB64:
     case R_WASM_MEMORY_ADDR_SLEB64:
     case R_WASM_MEMORY_ADDR_REL_SLEB64:
+    case R_WASM_MEMORY_ADDR_TLS_SLEB64:
       encodeSLEB128(static_cast<int64_t>(value), loc, 10);
       break;
     case R_WASM_TABLE_INDEX_I32:
diff --git a/lld/wasm/InputFiles.cpp b/lld/wasm/InputFiles.cpp
--- a/lld/wasm/InputFiles.cpp
+++ b/lld/wasm/InputFiles.cpp
@@ -124,6 +124,7 @@
   case R_WASM_MEMORY_ADDR_I32:
   case R_WASM_MEMORY_ADDR_I64:
   case R_WASM_MEMORY_ADDR_TLS_SLEB:
+  case R_WASM_MEMORY_ADDR_TLS_SLEB64:
   case R_WASM_FUNCTION_OFFSET_I32:
   case R_WASM_FUNCTION_OFFSET_I64:
   case R_WASM_MEMORY_ADDR_LOCREL_I32:
@@ -196,6 +197,7 @@
     return value;
   }
   case R_WASM_MEMORY_ADDR_TLS_SLEB:
+  case R_WASM_MEMORY_ADDR_TLS_SLEB64:
     if (isa<UndefinedData>(sym) || sym->isUndefWeak())
       return 0;
     // TLS relocations are relative to the start of the TLS output segment
diff --git a/lld/wasm/Relocations.cpp b/lld/wasm/Relocations.cpp
--- a/lld/wasm/Relocations.cpp
+++ b/lld/wasm/Relocations.cpp
@@ -115,6 +115,7 @@
         addGOTEntry(sym);
       break;
     case R_WASM_MEMORY_ADDR_TLS_SLEB:
+    case R_WASM_MEMORY_ADDR_TLS_SLEB64:
       // In single-threaded builds TLS is lowered away and TLS data can be
       // merged with normal data and allowing TLS relocation in non-TLS
       // segments.
diff --git a/llvm/include/llvm/BinaryFormat/WasmRelocs.def b/llvm/include/llvm/BinaryFormat/WasmRelocs.def
--- a/llvm/include/llvm/BinaryFormat/WasmRelocs.def
+++ b/llvm/include/llvm/BinaryFormat/WasmRelocs.def
@@ -27,3 +27,4 @@
 WASM_RELOC(R_WASM_FUNCTION_OFFSET_I64,    22)
 WASM_RELOC(R_WASM_MEMORY_ADDR_LOCREL_I32, 23)
 WASM_RELOC(R_WASM_TABLE_INDEX_REL_SLEB64, 24)
+WASM_RELOC(R_WASM_MEMORY_ADDR_TLS_SLEB64, 25)
diff --git a/llvm/lib/BinaryFormat/Wasm.cpp b/llvm/lib/BinaryFormat/Wasm.cpp
--- a/llvm/lib/BinaryFormat/Wasm.cpp
+++ b/llvm/lib/BinaryFormat/Wasm.cpp
@@ -49,6 +49,7 @@
   case R_WASM_MEMORY_ADDR_I32:
   case R_WASM_MEMORY_ADDR_I64:
   case R_WASM_MEMORY_ADDR_TLS_SLEB:
+  case R_WASM_MEMORY_ADDR_TLS_SLEB64:
   case R_WASM_FUNCTION_OFFSET_I32:
   case R_WASM_FUNCTION_OFFSET_I64:
   case R_WASM_SECTION_OFFSET_I32:
diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -633,6 +633,7 @@
   case wasm::R_WASM_MEMORY_ADDR_I32:
   case wasm::R_WASM_MEMORY_ADDR_I64:
   case wasm::R_WASM_MEMORY_ADDR_TLS_SLEB:
+  case wasm::R_WASM_MEMORY_ADDR_TLS_SLEB64:
   case wasm::R_WASM_MEMORY_ADDR_LOCREL_I32: {
     // Provisional value is address of the global plus the offset
     // For undefined symbols, use zero
@@ -748,6 +749,7 @@
     case wasm::R_WASM_TABLE_INDEX_REL_SLEB64:
     case wasm::R_WASM_MEMORY_ADDR_SLEB64:
     case wasm::R_WASM_MEMORY_ADDR_REL_SLEB64:
+    case wasm::R_WASM_MEMORY_ADDR_TLS_SLEB64:
       writePatchableSLEB<10>(Stream, Value, Offset);
       break;
     default:
diff --git a/llvm/lib/Object/WasmObjectFile.cpp b/llvm/lib/Object/WasmObjectFile.cpp
--- a/llvm/lib/Object/WasmObjectFile.cpp
+++ b/llvm/lib/Object/WasmObjectFile.cpp
@@ -919,6 +919,7 @@
     case wasm::R_WASM_MEMORY_ADDR_SLEB64:
     case wasm::R_WASM_MEMORY_ADDR_I64:
     case wasm::R_WASM_MEMORY_ADDR_REL_SLEB64:
+    case wasm::R_WASM_MEMORY_ADDR_TLS_SLEB64:
       if (!isValidDataSymbol(Reloc.Index))
         return make_error<GenericBinaryError>("invalid relocation data index",
                                               object_error::parse_failed);
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
@@ -79,7 +79,8 @@
       return is64Bit() ? wasm::R_WASM_TABLE_INDEX_REL_SLEB64
                        : wasm::R_WASM_TABLE_INDEX_REL_SLEB;
     case MCSymbolRefExpr::VK_WASM_TLSREL:
-      return wasm::R_WASM_MEMORY_ADDR_TLS_SLEB;
+      return is64Bit() ? wasm::R_WASM_MEMORY_ADDR_TLS_SLEB64
+                       : wasm::R_WASM_MEMORY_ADDR_TLS_SLEB;
     case MCSymbolRefExpr::VK_WASM_MBREL:
       assert(SymA.isData());
       return is64Bit() ? wasm::R_WASM_MEMORY_ADDR_REL_SLEB64
diff --git a/llvm/test/MC/WebAssembly/tls.s b/llvm/test/MC/WebAssembly/tls.s
--- a/llvm/test/MC/WebAssembly/tls.s
+++ b/llvm/test/MC/WebAssembly/tls.s
@@ -9,11 +9,12 @@
   # CHECK: global.get __tls_base
   # CHECK-NEXT: i32.const tls1@TLSREL
   # CHECK-NEXT: i32.add
+  # CHECK-NEXT: local.get 0
   # CHECK-NEXT: i32.store 0
-  local.get 0
   global.get __tls_base
   i32.const tls1@TLSREL
   i32.add
+  local.get 0
   i32.store 0
   end_function
 
@@ -33,10 +34,10 @@
 # CHECK-OBJ-NEXT:    Relocations:
 # CHECK-OBJ-NEXT:      - Type:            R_WASM_GLOBAL_INDEX_LEB
 # CHECK-OBJ-NEXT:        Index:           1
-# CHECK-OBJ-NEXT:        Offset:          0x6
+# CHECK-OBJ-NEXT:        Offset:          0x4
 # CHECK-OBJ-NEXT:      - Type:            R_WASM_MEMORY_ADDR_TLS_SLEB
 # CHECK-OBJ-NEXT:        Index:           2
-# CHECK-OBJ-NEXT:        Offset:          0xC
+# CHECK-OBJ-NEXT:        Offset:          0xA
 
 #      CHECK-OBJ:  - Type:            CUSTOM
 # CHECK-OBJ-NEXT:    Name:            linking
diff --git a/llvm/test/MC/WebAssembly/tls.s b/llvm/test/MC/WebAssembly/tls64.s
copy from llvm/test/MC/WebAssembly/tls.s
copy to llvm/test/MC/WebAssembly/tls64.s
--- a/llvm/test/MC/WebAssembly/tls.s
+++ b/llvm/test/MC/WebAssembly/tls64.s
@@ -1,19 +1,20 @@
-# RUN: llvm-mc -triple=wasm32-unknown-unknown < %s | FileCheck %s
-# RUN: llvm-mc -triple=wasm32-unknown-unknown -filetype=obj -o %t.o < %s
-# RUN: obj2yaml %t.o | FileCheck %s --check-prefix=CHECK-OBJ
+# RUN: llvm-mc -triple=wasm64-unknown-unknown < %s | FileCheck %s
+# RUN: llvm-mc -triple=wasm64-unknown-unknown -filetype=obj -o %t.o < %s
+# RUN: obj2yaml %t.o | FileCheck %s --check-prefix=CHECK-OBJ --match-full-lines
 
-.globaltype __tls_base, i32
+.globaltype __tls_base, i64
 
 tls_store:
   .functype tls_store (i32) -> ()
   # CHECK: global.get __tls_base
-  # CHECK-NEXT: i32.const tls1@TLSREL
-  # CHECK-NEXT: i32.add
+  # CHECK-NEXT: i64.const tls1@TLSREL
+  # CHECK-NEXT: i64.add
+  # CHECK-NEXT: local.get 0
   # CHECK-NEXT: i32.store 0
-  local.get 0
   global.get __tls_base
-  i32.const tls1@TLSREL
-  i32.add
+  i64.const tls1@TLSREL
+  i64.add
+  local.get 0
   i32.store 0
   end_function
 
@@ -33,10 +34,10 @@
 # CHECK-OBJ-NEXT:    Relocations:
 # CHECK-OBJ-NEXT:      - Type:            R_WASM_GLOBAL_INDEX_LEB
 # CHECK-OBJ-NEXT:        Index:           1
-# CHECK-OBJ-NEXT:        Offset:          0x6
-# CHECK-OBJ-NEXT:      - Type:            R_WASM_MEMORY_ADDR_TLS_SLEB
+# CHECK-OBJ-NEXT:        Offset:          0x4
+# CHECK-OBJ-NEXT:      - Type:            R_WASM_MEMORY_ADDR_TLS_SLEB64
 # CHECK-OBJ-NEXT:        Index:           2
-# CHECK-OBJ-NEXT:        Offset:          0xC
+# CHECK-OBJ-NEXT:        Offset:          0xA
 
 #      CHECK-OBJ:  - Type:            CUSTOM
 # CHECK-OBJ-NEXT:    Name:            linking