diff --git a/lld/wasm/InputChunks.h b/lld/wasm/InputChunks.h
index f1174d937ad3b9..ed86662e75692e 100644
--- a/lld/wasm/InputChunks.h
+++ b/lld/wasm/InputChunks.h
@@ -81,12 +81,7 @@ class InputChunk {
   void writeRelocations(llvm::raw_ostream &os) const;
   void generateRelocationCode(raw_ostream &os) const;
 
-  bool isTLS() const {
-    // Older object files don't include WASM_SEG_FLAG_TLS and instead
-    // relied on the naming convention.
-    return flags & llvm::wasm::WASM_SEG_FLAG_TLS || name.startswith(".tdata") ||
-           name.startswith(".tbss");
-  }
+  bool isTLS() const { return flags & llvm::wasm::WASM_SEG_FLAG_TLS; }
 
   ObjFile *file;
   OutputSection *outputSec = nullptr;
@@ -113,11 +108,15 @@ class InputChunk {
   // Signals the chunk was discarded by COMDAT handling.
   unsigned discarded : 1;
 
+  // Signals that the chuck was implicitly marked as TLS based on its name
+  // alone. This is a compatibility mechanism to support older object files.
+  unsigned implicitTLS : 1;
+
 protected:
   InputChunk(ObjFile *f, Kind k, StringRef name, uint32_t alignment = 0,
              uint32_t flags = 0)
       : name(name), file(f), alignment(alignment), flags(flags), sectionKind(k),
-        live(!config->gcSections), discarded(false) {}
+        live(!config->gcSections), discarded(false), implicitTLS(false) {}
   ArrayRef<uint8_t> data() const { return rawData; }
   uint64_t getTombstone() const;
 
diff --git a/lld/wasm/InputFiles.cpp b/lld/wasm/InputFiles.cpp
index 35d8dd1ed7be70..3f87df07a95195 100644
--- a/lld/wasm/InputFiles.cpp
+++ b/lld/wasm/InputFiles.cpp
@@ -491,7 +491,14 @@ void ObjFile::parse(bool ignoreComdats) {
     } else
       seg = make<InputSegment>(s, this);
     seg->discarded = isExcludedByComdat(seg);
-
+    // Older object files did not include WASM_SEG_FLAG_TLS and instead
+    // relied on the naming convention.  To maintain compat with such objects
+    // we still imply the TLS flag based on the name of the segment.
+    if (!seg->isTLS() &&
+        (seg->name.startswith(".tdata") || seg->name.startswith(".tbss"))) {
+      seg->flags |= WASM_SEG_FLAG_TLS;
+      seg->implicitTLS = true;
+    }
     segments.emplace_back(seg);
   }
   setRelocs(segments, dataSection);
@@ -592,6 +599,9 @@ Symbol *ObjFile::createDefined(const WasmSymbol &sym) {
     InputChunk *seg = segments[sym.Info.DataRef.Segment];
     auto offset = sym.Info.DataRef.Offset;
     auto size = sym.Info.DataRef.Size;
+    if (seg->implicitTLS) {
+      flags |= WASM_SYMBOL_TLS;
+    }
     if (sym.isBindingLocal())
       return make<DefinedData>(name, flags, this, seg, offset, size);
     if (seg->discarded)
diff --git a/lld/wasm/Relocations.cpp b/lld/wasm/Relocations.cpp
index 1dca6d621b2624..06d7f5d6752b52 100644
--- a/lld/wasm/Relocations.cpp
+++ b/lld/wasm/Relocations.cpp
@@ -120,6 +120,12 @@ void scanRelocations(InputChunk *chunk) {
       // merged with normal data and allowing TLS relocation in non-TLS
       // segments.
       if (config->sharedMemory) {
+        if (!sym->isTLS()) {
+          error(toString(file) + ": relocation " +
+                relocTypeToString(reloc.Type) +
+                " cannot be used against non-TLS symbol `" + toString(*sym) +
+                "`");
+        }
         if (auto *D = dyn_cast<DefinedData>(sym)) {
           if (!D->segment->outputSeg->isTLS()) {
             error(toString(file) + ": relocation " +
@@ -133,6 +139,12 @@ void scanRelocations(InputChunk *chunk) {
     }
 
     if (config->isPic) {
+      if (sym->isTLS() && sym->isUndefined()) {
+        error(toString(file) +
+              ": TLS symbol is undefined, but TLS symbols cannot yet be "
+              "imported: `" +
+              toString(*sym) + "`");
+      }
       switch (reloc.Type) {
       case R_WASM_TABLE_INDEX_SLEB:
       case R_WASM_TABLE_INDEX_SLEB64:
@@ -146,15 +158,6 @@ void scanRelocations(InputChunk *chunk) {
               " cannot be used against symbol " + toString(*sym) +
               "; recompile with -fPIC");
         break;
-      case R_WASM_MEMORY_ADDR_TLS_SLEB:
-      case R_WASM_MEMORY_ADDR_TLS_SLEB64:
-        if (!sym->isDefined()) {
-          error(toString(file) +
-                ": TLS symbol is undefined, but TLS symbols cannot yet be "
-                "imported: `" +
-                toString(*sym) + "`");
-        }
-        break;
       case R_WASM_TABLE_INDEX_I32:
       case R_WASM_TABLE_INDEX_I64:
       case R_WASM_MEMORY_ADDR_I32:
diff --git a/lld/wasm/Symbols.cpp b/lld/wasm/Symbols.cpp
index 09b5badb9c07c3..fd13b70f8c6dac 100644
--- a/lld/wasm/Symbols.cpp
+++ b/lld/wasm/Symbols.cpp
@@ -205,6 +205,8 @@ bool Symbol::isHidden() const {
   return (flags & WASM_SYMBOL_VISIBILITY_MASK) == WASM_SYMBOL_VISIBILITY_HIDDEN;
 }
 
+bool Symbol::isTLS() const { return flags & WASM_SYMBOL_TLS; }
+
 void Symbol::setHidden(bool isHidden) {
   LLVM_DEBUG(dbgs() << "setHidden: " << name << " -> " << isHidden << "\n");
   flags &= ~WASM_SYMBOL_VISIBILITY_MASK;
diff --git a/lld/wasm/Symbols.h b/lld/wasm/Symbols.h
index ef2ae7f457af90..415881e0c19823 100644
--- a/lld/wasm/Symbols.h
+++ b/lld/wasm/Symbols.h
@@ -74,6 +74,7 @@ class Symbol {
   bool isLocal() const;
   bool isWeak() const;
   bool isHidden() const;
+  bool isTLS() const;
 
   // Returns true if this symbol exists in a discarded (due to COMDAT) section
   bool isDiscarded() const;
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
index 82a2499081fb82..eff5bf5b4213f9 100644
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -639,7 +639,7 @@ void Writer::calculateExports() {
     } else if (auto *t = dyn_cast<DefinedTag>(sym)) {
       export_ = {name, WASM_EXTERNAL_TAG, t->getTagIndex()};
     } else if (auto *d = dyn_cast<DefinedData>(sym)) {
-      if (d->segment && d->segment->isTLS()) {
+      if (sym->isTLS()) {
         // We can't currenly export TLS data symbols.
         if (sym->isExportedExplicit())
           error("TLS symbols cannot yet be exported: `" + toString(*sym) + "`");
diff --git a/llvm/include/llvm/BinaryFormat/Wasm.h b/llvm/include/llvm/BinaryFormat/Wasm.h
index c38e64928521f3..1d0eb7009c7cc9 100644
--- a/llvm/include/llvm/BinaryFormat/Wasm.h
+++ b/llvm/include/llvm/BinaryFormat/Wasm.h
@@ -379,6 +379,7 @@ const unsigned WASM_SYMBOL_UNDEFINED = 0x10;
 const unsigned WASM_SYMBOL_EXPORTED = 0x20;
 const unsigned WASM_SYMBOL_EXPLICIT_NAME = 0x40;
 const unsigned WASM_SYMBOL_NO_STRIP = 0x80;
+const unsigned WASM_SYMBOL_TLS = 0x100;
 
 #define WASM_RELOC(name, value) name = value,
 
diff --git a/llvm/include/llvm/MC/MCSymbolWasm.h b/llvm/include/llvm/MC/MCSymbolWasm.h
index 852ab678e61652..7feffb4a6929fc 100644
--- a/llvm/include/llvm/MC/MCSymbolWasm.h
+++ b/llvm/include/llvm/MC/MCSymbolWasm.h
@@ -67,6 +67,11 @@ class MCSymbolWasm : public MCSymbol {
     modifyFlags(wasm::WASM_SYMBOL_NO_STRIP, wasm::WASM_SYMBOL_NO_STRIP);
   }
 
+  bool isTLS() const { return getFlags() & wasm::WASM_SYMBOL_TLS; }
+  void setTLS() const {
+    modifyFlags(wasm::WASM_SYMBOL_TLS, wasm::WASM_SYMBOL_TLS);
+  }
+
   bool isWeak() const { return IsWeak; }
   void setWeak(bool isWeak) { IsWeak = isWeak; }
 
diff --git a/llvm/include/llvm/MC/MCWasmStreamer.h b/llvm/include/llvm/MC/MCWasmStreamer.h
index 6651f071f799dc..818f59e5ab3e57 100644
--- a/llvm/include/llvm/MC/MCWasmStreamer.h
+++ b/llvm/include/llvm/MC/MCWasmStreamer.h
@@ -41,6 +41,9 @@ class MCWasmStreamer : public MCObjectStreamer {
   /// @{
 
   void changeSection(MCSection *Section, const MCExpr *Subsection) override;
+  void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
+  void emitLabelAtPos(MCSymbol *Symbol, SMLoc Loc, MCFragment *F,
+                      uint64_t Offset) override;
   void emitAssemblerFlag(MCAssemblerFlag Flag) override;
   void emitThumbFunc(MCSymbol *Func) override;
   void emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override;
@@ -68,6 +71,8 @@ class MCWasmStreamer : public MCObjectStreamer {
   void emitInstToFragment(const MCInst &Inst, const MCSubtargetInfo &) override;
   void emitInstToData(const MCInst &Inst, const MCSubtargetInfo &) override;
 
+  void fixSymbolsInTLSFixups(const MCExpr *expr);
+
   /// Merge the content of the fragment \p EF into the fragment \p DF.
   void mergeFragment(MCDataFragment *, MCDataFragment *);
 
diff --git a/llvm/lib/MC/MCWasmStreamer.cpp b/llvm/lib/MC/MCWasmStreamer.cpp
index e3d2439cef8171..47951bd5e8726f 100644
--- a/llvm/lib/MC/MCWasmStreamer.cpp
+++ b/llvm/lib/MC/MCWasmStreamer.cpp
@@ -49,6 +49,27 @@ void MCWasmStreamer::mergeFragment(MCDataFragment *DF, MCDataFragment *EF) {
   DF->getContents().append(EF->getContents().begin(), EF->getContents().end());
 }
 
+void MCWasmStreamer::emitLabel(MCSymbol *S, SMLoc Loc) {
+  auto *Symbol = cast<MCSymbolWasm>(S);
+  MCObjectStreamer::emitLabel(Symbol, Loc);
+
+  const MCSectionWasm &Section =
+      static_cast<const MCSectionWasm &>(*getCurrentSectionOnly());
+  if (Section.getSegmentFlags() & wasm::WASM_SEG_FLAG_TLS)
+    Symbol->setTLS();
+}
+
+void MCWasmStreamer::emitLabelAtPos(MCSymbol *S, SMLoc Loc, MCFragment *F,
+                                    uint64_t Offset) {
+  auto *Symbol = cast<MCSymbolWasm>(S);
+  MCObjectStreamer::emitLabelAtPos(Symbol, Loc, F, Offset);
+
+  const MCSectionWasm &Section =
+      static_cast<const MCSectionWasm &>(*getCurrentSectionOnly());
+  if (Section.getSegmentFlags() & wasm::WASM_SEG_FLAG_TLS)
+    Symbol->setTLS();
+}
+
 void MCWasmStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {
   // Let the target do whatever target specific stuff it needs to do.
   getAssembler().getBackend().handleAssemblerFlag(Flag);
@@ -117,6 +138,10 @@ bool MCWasmStreamer::emitSymbolAttribute(MCSymbol *S, MCSymbolAttr Attribute) {
     Symbol->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
     break;
 
+  case MCSA_ELF_TypeTLS:
+    Symbol->setTLS();
+    break;
+
   case MCSA_ELF_TypeObject:
   case MCSA_Cold:
     break;
@@ -156,6 +181,10 @@ void MCWasmStreamer::emitIdent(StringRef IdentString) {
 void MCWasmStreamer::emitInstToFragment(const MCInst &Inst,
                                         const MCSubtargetInfo &STI) {
   this->MCObjectStreamer::emitInstToFragment(Inst, STI);
+  MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());
+
+  for (auto &Fixup : F.getFixups())
+    fixSymbolsInTLSFixups(Fixup.getValue());
 }
 
 void MCWasmStreamer::emitInstToData(const MCInst &Inst,
@@ -166,6 +195,9 @@ void MCWasmStreamer::emitInstToData(const MCInst &Inst,
   raw_svector_ostream VecOS(Code);
   Assembler.getEmitter().encodeInstruction(Inst, VecOS, Fixups, STI);
 
+  for (auto &Fixup : Fixups)
+    fixSymbolsInTLSFixups(Fixup.getValue());
+
   // Append the encoded instruction to the current data fragment (or create a
   // new such fragment if the current fragment is not a data fragment).
   MCDataFragment *DF = getOrCreateDataFragment();
@@ -185,16 +217,32 @@ void MCWasmStreamer::finishImpl() {
   this->MCObjectStreamer::finishImpl();
 }
 
-MCStreamer *llvm::createWasmStreamer(MCContext &Context,
-                                     std::unique_ptr<MCAsmBackend> &&MAB,
-                                     std::unique_ptr<MCObjectWriter> &&OW,
-                                     std::unique_ptr<MCCodeEmitter> &&CE,
-                                     bool RelaxAll) {
-  MCWasmStreamer *S =
-      new MCWasmStreamer(Context, std::move(MAB), std::move(OW), std::move(CE));
-  if (RelaxAll)
-    S->getAssembler().setRelaxAll(true);
-  return S;
+void MCWasmStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
+  switch (expr->getKind()) {
+  case MCExpr::Target:
+  case MCExpr::Constant:
+    break;
+
+  case MCExpr::Binary: {
+    const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);
+    fixSymbolsInTLSFixups(be->getLHS());
+    fixSymbolsInTLSFixups(be->getRHS());
+    break;
+  }
+
+  case MCExpr::SymbolRef: {
+    const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);
+    if (symRef.getKind() == MCSymbolRefExpr::VK_WASM_TLSREL) {
+      getAssembler().registerSymbol(symRef.getSymbol());
+      cast<MCSymbolWasm>(symRef.getSymbol()).setTLS();
+    }
+    break;
+  }
+
+  case MCExpr::Unary:
+    fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
+    break;
+  }
 }
 
 void MCWasmStreamer::emitThumbFunc(MCSymbol *Func) {
@@ -215,3 +263,15 @@ void MCWasmStreamer::emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
                                     uint64_t Size, unsigned ByteAlignment) {
   llvm_unreachable("Wasm doesn't support this directive");
 }
+
+MCStreamer *llvm::createWasmStreamer(MCContext &Context,
+                                     std::unique_ptr<MCAsmBackend> &&MAB,
+                                     std::unique_ptr<MCObjectWriter> &&OW,
+                                     std::unique_ptr<MCCodeEmitter> &&CE,
+                                     bool RelaxAll) {
+  MCWasmStreamer *S =
+      new MCWasmStreamer(Context, std::move(MAB), std::move(OW), std::move(CE));
+  if (RelaxAll)
+    S->getAssembler().setRelaxAll(true);
+  return S;
+}
diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 7da5e1534bf153..2d16c3747180fb 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -1748,6 +1748,8 @@ uint64_t WasmObjectWriter::writeOneObject(MCAssembler &Asm,
       Flags |= wasm::WASM_SYMBOL_EXPLICIT_NAME;
     if (WS.hasExportName())
       Flags |= wasm::WASM_SYMBOL_EXPORTED;
+    if (WS.isTLS())
+      Flags |= wasm::WASM_SYMBOL_TLS;
 
     wasm::WasmSymbolInfo Info;
     Info.Name = WS.getName();
diff --git a/llvm/lib/ObjectYAML/WasmYAML.cpp b/llvm/lib/ObjectYAML/WasmYAML.cpp
index 752654ddbbaf14..365f63cce9bc3c 100644
--- a/llvm/lib/ObjectYAML/WasmYAML.cpp
+++ b/llvm/lib/ObjectYAML/WasmYAML.cpp
@@ -561,6 +561,7 @@ void ScalarBitSetTraits<WasmYAML::SymbolFlags>::bitset(
   BCaseMask(EXPORTED, EXPORTED);
   BCaseMask(EXPLICIT_NAME, EXPLICIT_NAME);
   BCaseMask(NO_STRIP, NO_STRIP);
+  BCaseMask(TLS, TLS);
 #undef BCaseMask
 }
 
diff --git a/llvm/test/MC/WebAssembly/tls.s b/llvm/test/MC/WebAssembly/tls.s
index 542273c339c30f..fc7c7c1b28b4db 100644
--- a/llvm/test/MC/WebAssembly/tls.s
+++ b/llvm/test/MC/WebAssembly/tls.s
@@ -18,6 +18,11 @@ tls_store:
   i32.store 0
   end_function
 
+tls_get_undefined:
+  .functype tls_get_undefined (i32) -> (i32)
+  i32.const tls_undefined@TLSREL
+  end_function
+
 .section .tls.foo,"T",@
 # CHECK: .tls.foo,"T",@
 tls1:
@@ -56,13 +61,22 @@ tls2:
 # CHECK-OBJ-NEXT:      - Index:           2
 # CHECK-OBJ-NEXT:        Kind:            DATA
 # CHECK-OBJ-NEXT:        Name:            tls1
-# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL ]
+# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL, TLS ]
 # CHECK-OBJ-NEXT:        Segment:         0
 # CHECK-OBJ-NEXT:        Size:            4
 # CHECK-OBJ-NEXT:      - Index:           3
+# CHECK-OBJ-NEXT:        Kind:            FUNCTION
+# CHECK-OBJ-NEXT:        Name:            tls_get_undefined
+# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL ]
+# CHECK-OBJ-NEXT:        Function:        1
+# CHECK-OBJ-NEXT:      - Index:           4
+# CHECK-OBJ-NEXT:        Kind:            DATA
+# CHECK-OBJ-NEXT:        Name:            tls_undefined
+# CHECK-OBJ-NEXT:        Flags:           [ UNDEFINED, TLS ]
+# CHECK-OBJ-NEXT:      - Index:           5
 # CHECK-OBJ-NEXT:        Kind:            DATA
 # CHECK-OBJ-NEXT:        Name:            tls2
-# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL ]
+# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL, TLS ]
 # CHECK-OBJ-NEXT:        Segment:         1
 # CHECK-OBJ-NEXT:        Size:            4
 # CHECK-OBJ-NEXT:    SegmentInfo:
diff --git a/llvm/test/MC/WebAssembly/tls64.s b/llvm/test/MC/WebAssembly/tls64.s
index f066fd29424e27..9d6dd5a0f729a6 100644
--- a/llvm/test/MC/WebAssembly/tls64.s
+++ b/llvm/test/MC/WebAssembly/tls64.s
@@ -56,13 +56,13 @@ tls2:
 # CHECK-OBJ-NEXT:      - Index:           2
 # CHECK-OBJ-NEXT:        Kind:            DATA
 # CHECK-OBJ-NEXT:        Name:            tls1
-# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL ]
+# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL, TLS ]
 # CHECK-OBJ-NEXT:        Segment:         0
 # CHECK-OBJ-NEXT:        Size:            4
 # CHECK-OBJ-NEXT:      - Index:           3
 # CHECK-OBJ-NEXT:        Kind:            DATA
 # CHECK-OBJ-NEXT:        Name:            tls2
-# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL ]
+# CHECK-OBJ-NEXT:        Flags:           [ BINDING_LOCAL, TLS ]
 # CHECK-OBJ-NEXT:        Segment:         1
 # CHECK-OBJ-NEXT:        Size:            4
 # CHECK-OBJ-NEXT:    SegmentInfo: