diff --git a/llvm/include/llvm/BinaryFormat/ELF.h b/llvm/include/llvm/BinaryFormat/ELF.h
--- a/llvm/include/llvm/BinaryFormat/ELF.h
+++ b/llvm/include/llvm/BinaryFormat/ELF.h
@@ -976,6 +976,7 @@
   // https://android.googlesource.com/platform/bionic/+/6f12bfece5dcc01325e0abba56a46b1bcf991c69/tools/relocation_packer/src/elf_file.cc#37
   SHT_ANDROID_REL = 0x60000001,
   SHT_ANDROID_RELA = 0x60000002,
+  SHT_ANDROID_MEMTAG_GLOBALS = 0x60000003,
   SHT_LLVM_ODRTAB = 0x6fff4c00,         // LLVM ODR table.
   SHT_LLVM_LINKER_OPTIONS = 0x6fff4c01, // LLVM Linker Options.
   SHT_LLVM_ADDRSIG = 0x6fff4c03,        // List of address-significant symbols
@@ -1578,6 +1579,7 @@
   NT_ANDROID_TYPE_IDENT = 1,
   NT_ANDROID_TYPE_KUSER = 3,
   NT_ANDROID_TYPE_MEMTAG = 4,
+  NT_ANDROID_TYPE_MEMTAG_GLOBALS = 8,
 };
 
 // Memory tagging values used in NT_ANDROID_TYPE_MEMTAG notes.
@@ -1593,7 +1595,8 @@
   NT_MEMTAG_LEVEL_SYNC = 2,
   NT_MEMTAG_LEVEL_MASK = 3,
   // Bits indicating whether the loader should prepare for MTE to be enabled on
-  // the heap and/or stack.
+  // the heap and/or stack. Whether globals are protected or not depends on the
+  // presence of the NT_ANDROID_TYPE_MEMTAG_GLOBALS note.
   NT_MEMTAG_HEAP = 4,
   NT_MEMTAG_STACK = 8,
 };
diff --git a/llvm/include/llvm/MC/MCAsmInfo.h b/llvm/include/llvm/MC/MCAsmInfo.h
--- a/llvm/include/llvm/MC/MCAsmInfo.h
+++ b/llvm/include/llvm/MC/MCAsmInfo.h
@@ -442,6 +442,8 @@
   /// protected visibility.  Defaults to MCSA_Protected
   MCSymbolAttr ProtectedVisibilityAttr = MCSA_Protected;
 
+  MCSymbolAttr TaggedAttr = MCSA_Tagged;
+
   //===--- Dwarf Emission Directives -----------------------------------===//
 
   /// True if target supports emission of debugging information.  Defaults to
@@ -772,6 +774,8 @@
     return ProtectedVisibilityAttr;
   }
 
+  MCSymbolAttr getTaggedAttr() const { return TaggedAttr; }
+
   bool doesSupportDebugInformation() const { return SupportsDebugInformation; }
 
   ExceptionHandling getExceptionHandlingType() const { return ExceptionsType; }
diff --git a/llvm/include/llvm/MC/MCDirectives.h b/llvm/include/llvm/MC/MCDirectives.h
--- a/llvm/include/llvm/MC/MCDirectives.h
+++ b/llvm/include/llvm/MC/MCDirectives.h
@@ -45,7 +45,8 @@
   MCSA_Weak,                    ///< .weak
   MCSA_WeakDefinition,          ///< .weak_definition (MachO)
   MCSA_WeakReference,           ///< .weak_reference (MachO)
-  MCSA_WeakDefAutoPrivate       ///< .weak_def_can_be_hidden (MachO)
+  MCSA_WeakDefAutoPrivate,      ///< .weak_def_can_be_hidden (MachO)
+  MCSA_Tagged                   ///< .tagged (ELF)
 };
 
 enum MCAssemblerFlag {
diff --git a/llvm/include/llvm/MC/MCELFObjectWriter.h b/llvm/include/llvm/MC/MCELFObjectWriter.h
--- a/llvm/include/llvm/MC/MCELFObjectWriter.h
+++ b/llvm/include/llvm/MC/MCELFObjectWriter.h
@@ -139,6 +139,14 @@
   unsigned setRSsym(unsigned Value, unsigned Type) const {
     return (Type & R_SSYM_MASK) | ((Value & 0xff) << R_SSYM_SHIFT);
   }
+
+  // On AArch64, returns a new section to be added to the ELF object that
+  // contains relocations used to describe every symbol that should have memory
+  // tags applied. Returns nullptr if no such section is necessary (i.e. there's
+  // no tagged globals).
+  virtual MCSectionELF *getMemtagRelocsSection(MCContext &Ctx) const {
+    return nullptr;
+  }
 };
 
 /// Construct a new ELF writer instance.
diff --git a/llvm/include/llvm/MC/MCSymbolELF.h b/llvm/include/llvm/MC/MCSymbolELF.h
--- a/llvm/include/llvm/MC/MCSymbolELF.h
+++ b/llvm/include/llvm/MC/MCSymbolELF.h
@@ -43,6 +43,9 @@
   void setIsSignature() const;
   bool isSignature() const;
 
+  bool isMemoryTagged() const;
+  void setTagged(bool Tagged);
+
   static bool classof(const MCSymbol *S) { return S->isELF(); }
 
 private:
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -710,6 +710,12 @@
   // GV's or GVSym's attributes will be used for the EmittedSym.
   emitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
 
+  if (GV->hasSanitizerMetadata() && GV->isTagged()) {
+    assert(TM.getTargetTriple().getArch() == Triple::aarch64 &&
+           "Tagged symbols are only supported on aarch64.");
+    OutStreamer->emitSymbolAttribute(EmittedSym, MAI->getTaggedAttr());
+  }
+
   if (!GV->hasInitializer())   // External globals require no extra code.
     return;
 
diff --git a/llvm/lib/MC/ELFObjectWriter.cpp b/llvm/lib/MC/ELFObjectWriter.cpp
--- a/llvm/lib/MC/ELFObjectWriter.cpp
+++ b/llvm/lib/MC/ELFObjectWriter.cpp
@@ -1084,6 +1084,21 @@
   // Write out the ELF header ...
   writeHeader(Asm);
 
+  MCSectionELF *MemtagRelocs = nullptr;
+  for (const MCSymbol &Sym : Asm.symbols()) {
+    const auto &SymE = cast<MCSymbolELF>(Sym);
+    if (!SymE.isMemoryTagged())
+      continue;
+    if (MemtagRelocs == nullptr) {
+      MemtagRelocs = OWriter.TargetObjectWriter->getMemtagRelocsSection(Ctx);
+      assert(MemtagRelocs != nullptr &&
+             "Tagged globals are only supported on AArch64");
+      Asm.registerSection(*MemtagRelocs);
+    }
+    ELFRelocationEntry Rec(0, &SymE, ELF::R_AARCH64_NONE, 0, nullptr, 0);
+    OWriter.Relocations[MemtagRelocs].push_back(Rec);
+  }
+
   // ... then the sections ...
   SectionOffsetsTy SectionOffsets;
   std::vector<MCSectionELF *> Groups;
@@ -1319,6 +1334,15 @@
     return true;
   }
 
+  // For memory-tagged symbols, ensure that the relocation uses the symbol. For
+  // tagged symbols, we emit an empty relocation (R_AARCH64_NONE) in a special
+  // section (SHT_ANDROID_MEMTAG_GLOBALS) to indicate to the linker that this
+  // global needs to be tagged. In addition, the linker needs to know whether to
+  // emit a special addend when relocating `end` symbols, and this can only be
+  // determined by the attributes of the symbol itself.
+  if (Sym->isMemoryTagged())
+    return true;
+
   // An undefined symbol is not in any section, so the relocation has to point
   // to the symbol itself.
   assert(Sym && "Expected a symbol");
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -764,6 +764,9 @@
   case MCSA_Exported:
     // Non-AIX assemblers currently do not support exported visibility.
     return false;
+  case MCSA_Tagged:
+    OS << "\t.tagged\t";
+    break;
   }
 
   Symbol->print(OS, MAI);
diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -286,6 +286,10 @@
     Symbol->setVisibility(ELF::STV_PROTECTED);
     break;
 
+  case MCSA_Tagged:
+    Symbol->setTagged(true);
+    break;
+
   case MCSA_Hidden:
     Symbol->setVisibility(ELF::STV_HIDDEN);
     break;
diff --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -360,6 +360,7 @@
   case MCSA_Local:
   case MCSA_LGlobal:
   case MCSA_Exported:
+  case MCSA_Tagged:
     return false;
 
   case MCSA_Global:
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -541,6 +541,7 @@
     DK_LTO_DISCARD,
     DK_LTO_SET_CONDITIONAL,
     DK_CFI_MTE_TAGGED_FRAME,
+    DK_TAGGED,
     DK_END
   };
 
@@ -2298,6 +2299,8 @@
       return parseDirectivePseudoProbe();
     case DK_LTO_DISCARD:
       return parseDirectiveLTODiscard();
+    case DK_TAGGED:
+      return parseDirectiveSymbolAttribute(MCSA_Tagged);
     }
 
     return Error(IDLoc, "unknown directive");
@@ -4986,8 +4989,9 @@
 
     MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 
-    // Assembler local symbols don't make any sense here. Complain loudly.
-    if (Sym->isTemporary())
+    // Assembler local symbols don't make any sense here, except for directives
+    // that the symbol should be tagged.
+    if (Sym->isTemporary() && Attr != MCSA_Tagged)
       return Error(Loc, "non-local symbol required");
 
     if (!getStreamer().emitSymbolAttribute(Sym, Attr))
@@ -5600,6 +5604,7 @@
   DirectiveKindMap[".pseudoprobe"] = DK_PSEUDO_PROBE;
   DirectiveKindMap[".lto_discard"] = DK_LTO_DISCARD;
   DirectiveKindMap[".lto_set_conditional"] = DK_LTO_SET_CONDITIONAL;
+  DirectiveKindMap[".tagged"] = DK_TAGGED;
 }
 
 MCAsmMacro *AsmParser::parseMacroLikeBody(SMLoc DirectiveLoc) {
diff --git a/llvm/lib/MC/MCSymbolELF.cpp b/llvm/lib/MC/MCSymbolELF.cpp
--- a/llvm/lib/MC/MCSymbolELF.cpp
+++ b/llvm/lib/MC/MCSymbolELF.cpp
@@ -33,7 +33,10 @@
   ELF_WeakrefUsedInReloc_Shift = 11,
 
   // One bit.
-  ELF_BindingSet_Shift = 12
+  ELF_BindingSet_Shift = 12,
+
+  // One bit.
+  ELF_IsMemoryTagged_Shift = 13,
 };
 }
 
@@ -193,4 +196,16 @@
 bool MCSymbolELF::isBindingSet() const {
   return getFlags() & (0x1 << ELF_BindingSet_Shift);
 }
+
+bool MCSymbolELF::isMemoryTagged() const {
+  return getFlags() & (0x1 << ELF_IsMemoryTagged_Shift);
+}
+
+void MCSymbolELF::setTagged(bool Tagged) {
+  uint32_t OtherFlags = getFlags() & ~(0x1 << ELF_IsMemoryTagged_Shift);
+  if (Tagged)
+    setFlags(OtherFlags | (0x1 << ELF_IsMemoryTagged_Shift));
+  else
+    setFlags(OtherFlags);
+}
 }
diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -181,6 +181,7 @@
   ECase(NT_ANDROID_TYPE_IDENT);
   ECase(NT_ANDROID_TYPE_KUSER);
   ECase(NT_ANDROID_TYPE_MEMTAG);
+  ECase(NT_ANDROID_TYPE_MEMTAG_GLOBALS);
 #undef ECase
   IO.enumFallback<Hex32>(Value);
 }
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
@@ -34,6 +34,8 @@
 
   ~AArch64ELFObjectWriter() override = default;
 
+  MCSectionELF* getMemtagRelocsSection(MCContext &Ctx) const override;
+
 protected:
   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
                         const MCFixup &Fixup, bool IsPCRel) const override;
@@ -453,6 +455,11 @@
   llvm_unreachable("Unimplemented fixup -> relocation");
 }
 
+MCSectionELF* AArch64ELFObjectWriter::getMemtagRelocsSection(MCContext &Ctx) const {
+  MCSectionELF *Sec = Ctx.getELFSection(".memtag.globals", ELF::SHT_ANDROID_MEMTAG_GLOBALS, 0);
+  return Sec;
+}
+
 std::unique_ptr<MCObjectTargetWriter>
 llvm::createAArch64ELFObjectWriter(uint8_t OSABI, bool IsILP32) {
   return std::make_unique<AArch64ELFObjectWriter>(OSABI, IsILP32);
diff --git a/llvm/test/CodeGen/AArch64/global-tagging.ll b/llvm/test/CodeGen/AArch64/global-tagging.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/global-tagging.ll
@@ -0,0 +1,45 @@
+; RUN: llc %s -mtriple=aarch64-linux-android31 -o %t.S
+; RUN: FileCheck %s --input-file=%t.S --check-prefix=CHECK-ASM
+; RUN: llvm-mc -filetype=obj %t.S -triple=aarch64-linux-android31 -o %t.o
+; RUN: llvm-objdump -r %t.o | FileCheck %s --check-prefix=CHECK-RELOCS
+
+; RUN: obj2yaml %t.o > %t.yaml
+; RUN: FileCheck %s --input-file=%t.yaml --check-prefix=CHECK-YAML
+; RUN: yaml2obj %t.yaml -o %t.o
+; RUN: llvm-objdump -r %t.o | FileCheck %s --check-prefix=CHECK-RELOCS
+
+; CHECK-RELOCS: RELOCATION RECORDS FOR [.memtag.globals]:
+; CHECK-RELOCS-NEXT: OFFSET TYPE VALUE
+; CHECK-YAML: Sections:
+; CHECK-YAML: - Name: .rela.memtag.globals
+; CHECK-YAML-NOT: - Name:
+; CHECK-YAML: Relocations:
+
+; CHECK-ASM: .tagged internal_four
+; CHECK-RELOCS-NEXT: R_AARCH64_NONE internal_four
+; CHECK-YAML-NEXT: - Symbol: internal_four
+; CHECK-YAML-NEXT: Type: R_AARCH64_NONE
+@internal_four = internal global i32 1, sanitize_memtag
+
+; CHECK-ASM: .tagged four
+; CHECK-RELOCS-NEXT: R_AARCH64_NONE four
+; CHECK-YAML-NEXT: - Symbol: four
+; CHECK-YAML-NEXT: Type: R_AARCH64_NONE
+@four = global i32 1, sanitize_memtag
+
+; CHECK-ASM: .tagged sixteen
+; CHECK-RELOCS-NEXT: R_AARCH64_NONE sixteen
+; CHECK-YAML-NEXT: - Symbol: sixteen
+; CHECK-YAML-NEXT: Type: R_AARCH64_NONE
+@sixteen = global [16 x i8] zeroinitializer, sanitize_memtag
+
+; CHECK-ASM: .tagged huge
+; CHECK-RELOCS-NEXT: R_AARCH64_NONE huge
+; CHECK-YAML-NEXT: - Symbol: huge
+; CHECK-YAML-NEXT: Type: R_AARCH64_NONE
+@huge = global [16777232 x i8] zeroinitializer, sanitize_memtag
+
+; CHECK-ASM-NOT: .tagged specialcaselisted
+; CHECK-RELOCS-NOT: R_AARCH64_NONE specialcaselisted
+; CHECK-YAML-NEXT: -
+@specialcaselisted = global i16 2, no_sanitize_memtag