diff --git a/include/llvm/ADT/Triple.h b/include/llvm/ADT/Triple.h
index 70d8879bf05..25494c55392 100644
--- a/include/llvm/ADT/Triple.h
+++ b/include/llvm/ADT/Triple.h
@@ -219,6 +219,7 @@ public:
     ELF,
     MachO,
     Wasm,
+    XCOFF,
   };
 
 private:
@@ -598,6 +599,11 @@ public:
            !isAndroid();
   }
 
+  /// Tests whether the OS is AIX.
+  bool isOSAIX() const {
+    return getOS() == Triple::AIX;
+  }
+
   /// Tests whether the OS uses the ELF binary format.
   bool isOSBinFormatELF() const {
     return getObjectFormat() == Triple::ELF;
@@ -618,6 +624,11 @@ public:
     return getObjectFormat() == Triple::Wasm;
   }
 
+  /// Tests whether the OS uses the XCOFF binary format.
+  bool isOSBinFormatXCOFF() const {
+    return getObjectFormat() == Triple::XCOFF;
+  }
+
   /// Tests whether the target is the PS4 CPU
   bool isPS4CPU() const {
     return getArch() == Triple::x86_64 &&
diff --git a/include/llvm/MC/MCObjectFileInfo.h b/include/llvm/MC/MCObjectFileInfo.h
index 0c1ade48fec..5d45d21a3a2 100644
--- a/include/llvm/MC/MCObjectFileInfo.h
+++ b/include/llvm/MC/MCObjectFileInfo.h
@@ -380,7 +380,7 @@ public:
     return EHFrameSection;
   }
 
-  enum Environment { IsMachO, IsELF, IsCOFF, IsWasm };
+  enum Environment { IsMachO, IsELF, IsCOFF, IsWasm, IsXCOFF };
   Environment getObjectFileType() const { return Env; }
 
   bool isPositionIndependent() const { return PositionIndependent; }
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index 69e18ed8998..49fad131a2c 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -161,6 +161,9 @@ MCSymbol *MCContext::createSymbolImpl(const StringMapEntry<bool> *Name,
       return new (Name, *this) MCSymbolMachO(Name, IsTemporary);
     case MCObjectFileInfo::IsWasm:
       return new (Name, *this) MCSymbolWasm(Name, IsTemporary);
+    case MCObjectFileInfo::IsXCOFF:
+      // TODO: Need to implement class MCSymbolXCOFF.
+      break;
     }
   }
   return new (Name, *this) MCSymbol(MCSymbol::SymbolKindUnset, Name,
diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index d9f1b2cb059..1c845f64050 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -801,6 +801,11 @@ void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
     Env = IsWasm;
     initWasmMCObjectFileInfo(TT);
     break;
+  case Triple::XCOFF:
+    Env = IsXCOFF;
+    // TODO: Initialize MCObjectFileInfo for XCOFF format when
+    // MCSectionXCOFF is ready.
+    break;
   case Triple::UnknownObjectFormat:
     report_fatal_error("Cannot initialize MC for unknown object file format.");
     break;
@@ -816,6 +821,7 @@ MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
   case Triple::MachO:
   case Triple::COFF:
   case Triple::Wasm:
+  case Triple::XCOFF:
   case Triple::UnknownObjectFormat:
     report_fatal_error("Cannot get DWARF comdat section for this object file "
                        "format: not implemented.");
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 4b487825935..a153ee184e3 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -710,6 +710,9 @@ AsmParser::AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
   case MCObjectFileInfo::IsWasm:
     PlatformParser.reset(createWasmAsmParser());
     break;
+  case MCObjectFileInfo::IsXCOFF:
+    // TODO: Need to implement createXCOFFAsmParser for XCOFF format.
+    break;
   }
 
   PlatformParser->Initialize(*this);
diff --git a/lib/Support/Triple.cpp b/lib/Support/Triple.cpp
index ab9fcccd5c4..83ce4f0f122 100644
--- a/lib/Support/Triple.cpp
+++ b/lib/Support/Triple.cpp
@@ -534,6 +534,9 @@ static Triple::EnvironmentType parseEnvironment(StringRef EnvironmentName) {
 
 static Triple::ObjectFormatType parseFormat(StringRef EnvironmentName) {
   return StringSwitch<Triple::ObjectFormatType>(EnvironmentName)
+    // "xcoff" must come before "coff" because of the order-dependendent
+    // pattern matching.
+    .EndsWith("xcoff", Triple::XCOFF)
     .EndsWith("coff", Triple::COFF)
     .EndsWith("elf", Triple::ELF)
     .EndsWith("macho", Triple::MachO)
@@ -622,6 +625,7 @@ static StringRef getObjectFormatTypeName(Triple::ObjectFormatType Kind) {
   case Triple::ELF: return "elf";
   case Triple::MachO: return "macho";
   case Triple::Wasm: return "wasm";
+  case Triple::XCOFF: return "xcoff";
   }
   llvm_unreachable("unknown object format type");
 }
@@ -686,6 +690,8 @@ static Triple::ObjectFormatType getDefaultFormat(const Triple &T) {
   case Triple::ppc64:
     if (T.isOSDarwin())
       return Triple::MachO;
+    else if (T.isOSAIX())
+      return Triple::XCOFF;
     return Triple::ELF;
 
   case Triple::wasm32:
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 76a0665239d..c3779233870 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -5594,6 +5594,9 @@ bool ARMAsmParser::parsePrefix(ARMMCExpr::VariantKind &RefKind) {
   case MCObjectFileInfo::IsWasm:
     CurrentFormat = WASM;
     break;
+  case MCObjectFileInfo::IsXCOFF:
+    llvm_unreachable("unexpected object format");
+    break;
   }
 
   if (~Prefix->SupportedFormats & CurrentFormat) {
diff --git a/unittests/ADT/TripleTest.cpp b/unittests/ADT/TripleTest.cpp
index 6ad6b62e90c..a83ef44211c 100644
--- a/unittests/ADT/TripleTest.cpp
+++ b/unittests/ADT/TripleTest.cpp
@@ -1258,6 +1258,11 @@ TEST(TripleTest, FileFormat) {
   EXPECT_EQ(Triple::Wasm,
             Triple("wasm64-unknown-wasi-musl-wasm").getObjectFormat());
 
+  EXPECT_EQ(Triple::XCOFF, Triple("powerpc-ibm-aix").getObjectFormat());
+  EXPECT_EQ(Triple::XCOFF, Triple("powerpc64-ibm-aix").getObjectFormat());
+  EXPECT_EQ(Triple::XCOFF, Triple("powerpc---xcoff").getObjectFormat());
+  EXPECT_EQ(Triple::XCOFF, Triple("powerpc64---xcoff").getObjectFormat());
+
   Triple MSVCNormalized(Triple::normalize("i686-pc-windows-msvc-elf"));
   EXPECT_EQ(Triple::ELF, MSVCNormalized.getObjectFormat());
 
@@ -1276,6 +1281,9 @@ TEST(TripleTest, FileFormat) {
 
   T.setObjectFormat(Triple::MachO);
   EXPECT_EQ(Triple::MachO, T.getObjectFormat());
+
+  T.setObjectFormat(Triple::XCOFF);
+  EXPECT_EQ(Triple::XCOFF, T.getObjectFormat());
 }
 
 TEST(TripleTest, NormalizeWindows) {