diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.h b/llvm/lib/Target/RISCV/RISCVInstrInfo.h
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.h
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.h
@@ -94,6 +94,13 @@
   bool areMemAccessesTriviallyDisjoint(const MachineInstr &MIa,
                                        const MachineInstr &MIb) const override;
 
+
+  std::pair<unsigned, unsigned>
+  decomposeMachineOperandsTargetFlags(unsigned TF) const override;
+
+  ArrayRef<std::pair<unsigned, const char *>>
+  getSerializableDirectMachineOperandTargetFlags() const override;
+
 protected:
   const RISCVSubtarget &STI;
 };
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -597,3 +597,28 @@
   }
   return false;
 }
+
+std::pair<unsigned, unsigned>
+RISCVInstrInfo::decomposeMachineOperandsTargetFlags(unsigned TF) const {
+  const unsigned Mask = RISCVII::MO_DIRECT_FLAG_MASK;
+  return std::make_pair(TF & Mask, TF & ~Mask);
+}
+
+ArrayRef<std::pair<unsigned, const char *>>
+RISCVInstrInfo::getSerializableDirectMachineOperandTargetFlags() const {
+  using namespace RISCVII;
+  static const std::pair<unsigned, const char *> TargetFlags[] = {
+      {MO_CALL, "riscv-call"},
+      {MO_PLT, "riscv-plt"},
+      {MO_LO, "riscv-lo"},
+      {MO_HI, "riscv-hi"},
+      {MO_PCREL_LO, "riscv-pcrel-lo"},
+      {MO_PCREL_HI, "riscv-pcrel-hi"},
+      {MO_GOT_HI, "riscv-got-hi"},
+      {MO_TPREL_LO, "riscv-tprel-lo"},
+      {MO_TPREL_HI, "riscv-tprel-hi"},
+      {MO_TPREL_ADD, "riscv-tprel-add"},
+      {MO_TLS_GOT_HI, "riscv-tls-got-hi"},
+      {MO_TLS_GD_HI, "riscv-tls-gd-hi"}};
+  return makeArrayRef(TargetFlags);
+}
diff --git a/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h b/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h
--- a/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h
+++ b/llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.h
@@ -48,20 +48,26 @@
   InstFormatMask = 31
 };
 
+// RISC-V Specific Machine Operand Flags
 enum {
-  MO_None,
-  MO_CALL,
-  MO_PLT,
-  MO_LO,
-  MO_HI,
-  MO_PCREL_LO,
-  MO_PCREL_HI,
-  MO_GOT_HI,
-  MO_TPREL_LO,
-  MO_TPREL_HI,
-  MO_TPREL_ADD,
-  MO_TLS_GOT_HI,
-  MO_TLS_GD_HI,
+  MO_None = 0,
+  MO_CALL = 1,
+  MO_PLT = 2,
+  MO_LO = 3,
+  MO_HI = 4,
+  MO_PCREL_LO = 5,
+  MO_PCREL_HI = 6,
+  MO_GOT_HI = 7,
+  MO_TPREL_LO = 8,
+  MO_TPREL_HI = 9,
+  MO_TPREL_ADD = 10,
+  MO_TLS_GOT_HI = 11,
+  MO_TLS_GD_HI = 12,
+
+  // Used to differentiate between target-specific "direct" flags and "bitmask"
+  // flags. A machine operand can only have one "direct" flag, but can have
+  // multiple "bitmask" flags.
+  MO_DIRECT_FLAG_MASK = 15
 };
 } // namespace RISCVII