Revert "Revert "[MIR] Target specific MIR formating and parsing""

There was an unguarded dereference of MF in a function that permitted
nullptr. Fixed

This reverts commit 71d64f72f934631aa2f12b9542c23f74f256f494.

8 files changed, 261 insertions, 117 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.cpp b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
index 21511586ff1..0c35a91f828 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
@@ -242,6 +242,7 @@ static MIToken::TokenKind getIdentifierKind(StringRef Identifier) {
       .Case("jump-table", MIToken::kw_jump_table)
       .Case("constant-pool", MIToken::kw_constant_pool)
       .Case("call-entry", MIToken::kw_call_entry)
+      .Case("custom", MIToken::kw_custom)
       .Case("liveout", MIToken::kw_liveout)
       .Case("address-taken", MIToken::kw_address_taken)
       .Case("landing-pad", MIToken::kw_landing_pad)
diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.h b/llvm/lib/CodeGen/MIRParser/MILexer.h
index 1e2eba91ceb..af5327cacfe 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.h
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.h
@@ -110,6 +110,7 @@ struct MIToken {
     kw_jump_table,
     kw_constant_pool,
     kw_call_entry,
+    kw_custom,
     kw_liveout,
     kw_address_taken,
     kw_landing_pad,
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 525c70016a0..0f2648e2bfa 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -28,6 +28,7 @@
 #include "llvm/AsmParser/SlotMapping.h"
 #include "llvm/CodeGen/GlobalISel/RegisterBank.h"
 #include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
+#include "llvm/CodeGen/MIRFormatter.h"
 #include "llvm/CodeGen/MIRPrinter.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
@@ -343,6 +344,37 @@ VRegInfo &PerFunctionMIParsingState::getVRegInfoNamed(StringRef RegName) {
   return *I.first->second;
 }
 
+static void mapValueToSlot(const Value *V, ModuleSlotTracker &MST,
+                           DenseMap<unsigned, const Value *> &Slots2Values) {
+  int Slot = MST.getLocalSlot(V);
+  if (Slot == -1)
+    return;
+  Slots2Values.insert(std::make_pair(unsigned(Slot), V));
+}
+
+/// Creates the mapping from slot numbers to function's unnamed IR values.
+static void initSlots2Values(const Function &F,
+                             DenseMap<unsigned, const Value *> &Slots2Values) {
+  ModuleSlotTracker MST(F.getParent(), /*ShouldInitializeAllMetadata=*/false);
+  MST.incorporateFunction(F);
+  for (const auto &Arg : F.args())
+    mapValueToSlot(&Arg, MST, Slots2Values);
+  for (const auto &BB : F) {
+    mapValueToSlot(&BB, MST, Slots2Values);
+    for (const auto &I : BB)
+      mapValueToSlot(&I, MST, Slots2Values);
+  }
+}
+
+const Value* PerFunctionMIParsingState::getIRValue(unsigned Slot) {
+  if (Slots2Values.empty())
+    initSlots2Values(MF.getFunction(), Slots2Values);
+  auto ValueInfo = Slots2Values.find(Slot);
+  if (ValueInfo == Slots2Values.end())
+    return nullptr;
+  return ValueInfo->second;
+}
+
 namespace {
 
 /// A wrapper struct around the 'MachineOperand' struct that includes a source
@@ -370,8 +402,6 @@ class MIParser {
   PerFunctionMIParsingState &PFS;
   /// Maps from slot numbers to function's unnamed basic blocks.
   DenseMap<unsigned, const BasicBlock *> Slots2BasicBlocks;
-  /// Maps from slot numbers to function's unnamed values.
-  DenseMap<unsigned, const Value *> Slots2Values;
 
 public:
   MIParser(PerFunctionMIParsingState &PFS, SMDiagnostic &Error,
@@ -455,9 +485,12 @@ public:
   bool parseTargetIndexOperand(MachineOperand &Dest);
   bool parseCustomRegisterMaskOperand(MachineOperand &Dest);
   bool parseLiveoutRegisterMaskOperand(MachineOperand &Dest);
-  bool parseMachineOperand(MachineOperand &Dest,
+  bool parseMachineOperand(const unsigned OpCode, const unsigned OpIdx,
+                           MachineOperand &Dest,
                            Optional<unsigned> &TiedDefIdx);
-  bool parseMachineOperandAndTargetFlags(MachineOperand &Dest,
+  bool parseMachineOperandAndTargetFlags(const unsigned OpCode,
+                                         const unsigned OpIdx,
+                                         MachineOperand &Dest,
                                          Optional<unsigned> &TiedDefIdx);
   bool parseOffset(int64_t &Offset);
   bool parseAlignment(unsigned &Alignment);
@@ -473,6 +506,9 @@ public:
   bool parsePreOrPostInstrSymbol(MCSymbol *&Symbol);
   bool parseHeapAllocMarker(MDNode *&Node);
 
+  bool parseTargetImmMnemonic(const unsigned OpCode, const unsigned OpIdx,
+                              MachineOperand &Dest, const MIRFormatter &MF);
+
 private:
   /// Convert the integer literal in the current token into an unsigned integer.
   ///
@@ -551,6 +587,9 @@ bool MIParser::error(StringRef::iterator Loc, const Twine &Msg) {
   return true;
 }
 
+typedef function_ref<bool(StringRef::iterator Loc, const Twine &)>
+    ErrorCallbackType;
+
 static const char *toString(MIToken::TokenKind TokenKind) {
   switch (TokenKind) {
   case MIToken::comma:
@@ -912,7 +951,7 @@ bool MIParser::parse(MachineInstr *&MI) {
          Token.isNot(MIToken::coloncolon) && Token.isNot(MIToken::lbrace)) {
     auto Loc = Token.location();
     Optional<unsigned> TiedDefIdx;
-    if (parseMachineOperandAndTargetFlags(MO, TiedDefIdx))
+    if (parseMachineOperandAndTargetFlags(OpCode, Operands.size(), MO, TiedDefIdx))
       return true;
     if (OpCode == TargetOpcode::DBG_VALUE && MO.isReg())
       MO.setIsDebug();
@@ -1493,17 +1532,61 @@ bool MIParser::parseImmediateOperand(MachineOperand &Dest) {
   return false;
 }
 
-bool MIParser::parseIRConstant(StringRef::iterator Loc, StringRef StringValue,
-                               const Constant *&C) {
+bool MIParser::parseTargetImmMnemonic(const unsigned OpCode,
+                                      const unsigned OpIdx,
+                                      MachineOperand &Dest,
+                                      const MIRFormatter &MF) {
+  assert(Token.is(MIToken::dot));
+  auto Loc = Token.location(); // record start position
+  size_t Len = 1;              // for "."
+  lex();
+
+  // Handle the case that mnemonic starts with number.
+  if (Token.is(MIToken::IntegerLiteral)) {
+    Len += Token.range().size();
+    lex();
+  }
+
+  StringRef Src;
+  if (Token.is(MIToken::comma))
+    Src = StringRef(Loc, Len);
+  else {
+    assert(Token.is(MIToken::Identifier));
+    Src = StringRef(Loc, Len + Token.stringValue().size());
+  }
+  int64_t Val;
+  if (MF.parseImmMnemonic(OpCode, OpIdx, Src, Val,
+                          [this](StringRef::iterator Loc, const Twine &Msg)
+                              -> bool { return error(Loc, Msg); }))
+    return true;
+
+  Dest = MachineOperand::CreateImm(Val);
+  if (!Token.is(MIToken::comma))
+    lex();
+  return false;
+}
+
+static bool parseIRConstant(StringRef::iterator Loc, StringRef StringValue,
+                            PerFunctionMIParsingState &PFS, const Constant *&C,
+                            ErrorCallbackType ErrCB) {
   auto Source = StringValue.str(); // The source has to be null terminated.
   SMDiagnostic Err;
-  C = parseConstantValue(Source, Err, *MF.getFunction().getParent(),
+  C = parseConstantValue(Source, Err, *PFS.MF.getFunction().getParent(),
                          &PFS.IRSlots);
   if (!C)
-    return error(Loc + Err.getColumnNo(), Err.getMessage());
+    return ErrCB(Loc + Err.getColumnNo(), Err.getMessage());
   return false;
 }
 
+bool MIParser::parseIRConstant(StringRef::iterator Loc, StringRef StringValue,
+                               const Constant *&C) {
+  return ::parseIRConstant(
+      Loc, StringValue, PFS, C,
+      [this](StringRef::iterator Loc, const Twine &Msg) -> bool {
+        return error(Loc, Msg);
+      });
+}
+
 bool MIParser::parseIRConstant(StringRef::iterator Loc, const Constant *&C) {
   if (parseIRConstant(Loc, StringRef(Loc, Token.range().end() - Loc), C))
     return true;
@@ -1636,27 +1719,52 @@ bool MIParser::parseFPImmediateOperand(MachineOperand &Dest) {
   return false;
 }
 
-bool MIParser::getUnsigned(unsigned &Result) {
+static bool getHexUint(const MIToken &Token, APInt &Result) {
+  assert(Token.is(MIToken::HexLiteral));
+  StringRef S = Token.range();
+  assert(S[0] == '0' && tolower(S[1]) == 'x');
+  // This could be a floating point literal with a special prefix.
+  if (!isxdigit(S[2]))
+    return true;
+  StringRef V = S.substr(2);
+  APInt A(V.size()*4, V, 16);
+
+  // If A is 0, then A.getActiveBits() is 0. This isn't a valid bitwidth. Make
+  // sure it isn't the case before constructing result.
+  unsigned NumBits = (A == 0) ? 32 : A.getActiveBits();
+  Result = APInt(NumBits, ArrayRef<uint64_t>(A.getRawData(), A.getNumWords()));
+  return false;
+}
+
+bool getUnsigned(const MIToken &Token, unsigned &Result,
+                 ErrorCallbackType ErrCB) {
   if (Token.hasIntegerValue()) {
     const uint64_t Limit = uint64_t(std::numeric_limits<unsigned>::max()) + 1;
     uint64_t Val64 = Token.integerValue().getLimitedValue(Limit);
     if (Val64 == Limit)
-      return error("expected 32-bit integer (too large)");
+      return ErrCB(Token.location(), "expected 32-bit integer (too large)");
     Result = Val64;
     return false;
   }
   if (Token.is(MIToken::HexLiteral)) {
     APInt A;
-    if (getHexUint(A))
+    if (getHexUint(Token, A))
       return true;
     if (A.getBitWidth() > 32)
-      return error("expected 32-bit integer (too large)");
+      return ErrCB(Token.location(), "expected 32-bit integer (too large)");
     Result = A.getZExtValue();
     return false;
   }
   return true;
 }
 
+bool MIParser::getUnsigned(unsigned &Result) {
+  return ::getUnsigned(
+      Token, Result, [this](StringRef::iterator Loc, const Twine &Msg) -> bool {
+        return error(Loc, Msg);
+      });
+}
+
 bool MIParser::parseMBBReference(MachineBasicBlock *&MBB) {
   assert(Token.is(MIToken::MachineBasicBlock) ||
          Token.is(MIToken::MachineBasicBlockLabel));
@@ -1736,23 +1844,25 @@ bool MIParser::parseFixedStackObjectOperand(MachineOperand &Dest) {
   return false;
 }
 
-bool MIParser::parseGlobalValue(GlobalValue *&GV) {
+static bool parseGlobalValue(const MIToken &Token,
+                             PerFunctionMIParsingState &PFS, GlobalValue *&GV,
+                             ErrorCallbackType ErrCB) {
   switch (Token.kind()) {
   case MIToken::NamedGlobalValue: {
-    const Module *M = MF.getFunction().getParent();
+    const Module *M = PFS.MF.getFunction().getParent();
     GV = M->getNamedValue(Token.stringValue());
     if (!GV)
-      return error(Twine("use of undefined global value '") + Token.range() +
-                   "'");
+      return ErrCB(Token.location(), Twine("use of undefined global value '") +
+                                         Token.range() + "'");
     break;
   }
   case MIToken::GlobalValue: {
     unsigned GVIdx;
-    if (getUnsigned(GVIdx))
+    if (getUnsigned(Token, GVIdx, ErrCB))
       return true;
     if (GVIdx >= PFS.IRSlots.GlobalValues.size())
-      return error(Twine("use of undefined global value '@") + Twine(GVIdx) +
-                   "'");
+      return ErrCB(Token.location(), Twine("use of undefined global value '@") +
+                                         Twine(GVIdx) + "'");
     GV = PFS.IRSlots.GlobalValues[GVIdx];
     break;
   }
@@ -1762,6 +1872,14 @@ bool MIParser::parseGlobalValue(GlobalValue *&GV) {
   return false;
 }
 
+bool MIParser::parseGlobalValue(GlobalValue *&GV) {
+  return ::parseGlobalValue(
+      Token, PFS, GV,
+      [this](StringRef::iterator Loc, const Twine &Msg) -> bool {
+        return error(Loc, Msg);
+      });
+}
+
 bool MIParser::parseGlobalAddressOperand(MachineOperand &Dest) {
   GlobalValue *GV = nullptr;
   if (parseGlobalValue(GV))
@@ -2410,7 +2528,8 @@ bool MIParser::parseLiveoutRegisterMaskOperand(MachineOperand &Dest) {
   return false;
 }
 
-bool MIParser::parseMachineOperand(MachineOperand &Dest,
+bool MIParser::parseMachineOperand(const unsigned OpCode, const unsigned OpIdx,
+                                   MachineOperand &Dest,
                                    Optional<unsigned> &TiedDefIdx) {
   switch (Token.kind()) {
   case MIToken::kw_implicit:
@@ -2499,6 +2618,12 @@ bool MIParser::parseMachineOperand(MachineOperand &Dest,
       return parseCustomRegisterMaskOperand(Dest);
     } else
       return parseTypedImmediateOperand(Dest);
+  case MIToken::dot: {
+    if (const auto *Formatter = MF.getTarget().getMIRFormatter()) {
+      return parseTargetImmMnemonic(OpCode, OpIdx, Dest, *Formatter);
+    }
+    LLVM_FALLTHROUGH;
+  }
   default:
     // FIXME: Parse the MCSymbol machine operand.
     return error("expected a machine operand");
@@ -2507,7 +2632,8 @@ bool MIParser::parseMachineOperand(MachineOperand &Dest,
 }
 
 bool MIParser::parseMachineOperandAndTargetFlags(
-    MachineOperand &Dest, Optional<unsigned> &TiedDefIdx) {
+    const unsigned OpCode, const unsigned OpIdx, MachineOperand &Dest,
+    Optional<unsigned> &TiedDefIdx) {
   unsigned TF = 0;
   bool HasTargetFlags = false;
   if (Token.is(MIToken::kw_target_flags)) {
@@ -2539,7 +2665,7 @@ bool MIParser::parseMachineOperandAndTargetFlags(
       return true;
   }
   auto Loc = Token.location();
-  if (parseMachineOperand(Dest, TiedDefIdx))
+  if (parseMachineOperand(OpCode, OpIdx, Dest, TiedDefIdx))
     return true;
   if (!HasTargetFlags)
     return false;
@@ -2600,30 +2726,31 @@ bool MIParser::parseOperandsOffset(MachineOperand &Op) {
   return false;
 }
 
-bool MIParser::parseIRValue(const Value *&V) {
+static bool parseIRValue(const MIToken &Token, PerFunctionMIParsingState &PFS,
+                         const Value *&V, ErrorCallbackType ErrCB) {
   switch (Token.kind()) {
   case MIToken::NamedIRValue: {
-    V = MF.getFunction().getValueSymbolTable()->lookup(Token.stringValue());
+    V = PFS.MF.getFunction().getValueSymbolTable()->lookup(Token.stringValue());
     break;
   }
   case MIToken::IRValue: {
     unsigned SlotNumber = 0;
-    if (getUnsigned(SlotNumber))
+    if (getUnsigned(Token, SlotNumber, ErrCB))
       return true;
-    V = getIRValue(SlotNumber);
+    V = PFS.getIRValue(SlotNumber);
     break;
   }
   case MIToken::NamedGlobalValue:
   case MIToken::GlobalValue: {
     GlobalValue *GV = nullptr;
-    if (parseGlobalValue(GV))
+    if (parseGlobalValue(Token, PFS, GV, ErrCB))
       return true;
     V = GV;
     break;
   }
   case MIToken::QuotedIRValue: {
     const Constant *C = nullptr;
-    if (parseIRConstant(Token.location(), Token.stringValue(), C))
+    if (parseIRConstant(Token.location(), Token.stringValue(), PFS, C, ErrCB))
       return true;
     V = C;
     break;
@@ -2632,10 +2759,17 @@ bool MIParser::parseIRValue(const Value *&V) {
     llvm_unreachable("The current token should be an IR block reference");
   }
   if (!V)
-    return error(Twine("use of undefined IR value '") + Token.range() + "'");
+    return ErrCB(Token.location(), Twine("use of undefined IR value '") + Token.range() + "'");
   return false;
 }
 
+bool MIParser::parseIRValue(const Value *&V) {
+  return ::parseIRValue(
+      Token, PFS, V, [this](StringRef::iterator Loc, const Twine &Msg) -> bool {
+        return error(Loc, Msg);
+      });
+}
+
 bool MIParser::getUint64(uint64_t &Result) {
   if (Token.hasIntegerValue()) {
     if (Token.integerValue().getActiveBits() > 64)
@@ -2656,20 +2790,7 @@ bool MIParser::getUint64(uint64_t &Result) {
 }
 
 bool MIParser::getHexUint(APInt &Result) {
-  assert(Token.is(MIToken::HexLiteral));
-  StringRef S = Token.range();
-  assert(S[0] == '0' && tolower(S[1]) == 'x');
-  // This could be a floating point literal with a special prefix.
-  if (!isxdigit(S[2]))
-    return true;
-  StringRef V = S.substr(2);
-  APInt A(V.size()*4, V, 16);
-
-  // If A is 0, then A.getActiveBits() is 0. This isn't a valid bitwidth. Make
-  // sure it isn't the case before constructing result.
-  unsigned NumBits = (A == 0) ? 32 : A.getActiveBits();
-  Result = APInt(NumBits, ArrayRef<uint64_t>(A.getRawData(), A.getNumWords()));
-  return false;
+  return ::getHexUint(Token, Result);
 }
 
 bool MIParser::parseMemoryOperandFlag(MachineMemOperand::Flags &Flags) {
@@ -2756,6 +2877,19 @@ bool MIParser::parseMemoryPseudoSourceValue(const PseudoSourceValue *&PSV) {
           "expected a global value or an external symbol after 'call-entry'");
     }
     break;
+  case MIToken::kw_custom: {
+    lex();
+    if (const auto *Formatter = MF.getTarget().getMIRFormatter()) {
+      if (Formatter->parseCustomPseudoSourceValue(
+              Token.stringValue(), MF, PFS, PSV,
+              [this](StringRef::iterator Loc, const Twine &Msg) -> bool {
+                return error(Loc, Msg);
+              }))
+        return true;
+    } else
+      return error("unable to parse target custom pseudo source value");
+    break;
+  }
   default:
     llvm_unreachable("The current token should be pseudo source value");
   }
@@ -2767,7 +2901,7 @@ bool MIParser::parseMachinePointerInfo(MachinePointerInfo &Dest) {
   if (Token.is(MIToken::kw_constant_pool) || Token.is(MIToken::kw_stack) ||
       Token.is(MIToken::kw_got) || Token.is(MIToken::kw_jump_table) ||
       Token.is(MIToken::FixedStackObject) || Token.is(MIToken::StackObject) ||
-      Token.is(MIToken::kw_call_entry)) {
+      Token.is(MIToken::kw_call_entry) || Token.is(MIToken::kw_custom)) {
     const PseudoSourceValue *PSV = nullptr;
     if (parseMemoryPseudoSourceValue(PSV))
       return true;
@@ -3018,35 +3152,8 @@ const BasicBlock *MIParser::getIRBlock(unsigned Slot, const Function &F) {
   return getIRBlockFromSlot(Slot, CustomSlots2BasicBlocks);
 }
 
-static void mapValueToSlot(const Value *V, ModuleSlotTracker &MST,
-                           DenseMap<unsigned, const Value *> &Slots2Values) {
-  int Slot = MST.getLocalSlot(V);
-  if (Slot == -1)
-    return;
-  Slots2Values.insert(std::make_pair(unsigned(Slot), V));
-}
-
-/// Creates the mapping from slot numbers to function's unnamed IR values.
-static void initSlots2Values(const Function &F,
-                             DenseMap<unsigned, const Value *> &Slots2Values) {
-  ModuleSlotTracker MST(F.getParent(), /*ShouldInitializeAllMetadata=*/false);
-  MST.incorporateFunction(F);
-  for (const auto &Arg : F.args())
-    mapValueToSlot(&Arg, MST, Slots2Values);
-  for (const auto &BB : F) {
-    mapValueToSlot(&BB, MST, Slots2Values);
-    for (const auto &I : BB)
-      mapValueToSlot(&I, MST, Slots2Values);
-  }
-}
-
 const Value *MIParser::getIRValue(unsigned Slot) {
-  if (Slots2Values.empty())
-    initSlots2Values(MF.getFunction(), Slots2Values);
-  auto ValueInfo = Slots2Values.find(Slot);
-  if (ValueInfo == Slots2Values.end())
-    return nullptr;
-  return ValueInfo->second;
+  return PFS.getIRValue(Slot);
 }
 
 MCSymbol *MIParser::getOrCreateMCSymbol(StringRef Name) {
@@ -3111,3 +3218,15 @@ bool llvm::parseMDNode(PerFunctionMIParsingState &PFS,
                        MDNode *&Node, StringRef Src, SMDiagnostic &Error) {
   return MIParser(PFS, Error, Src).parseStandaloneMDNode(Node);
 }
+
+bool MIRFormatter::parseIRValue(StringRef Src, MachineFunction &MF,
+                                PerFunctionMIParsingState &PFS, const Value *&V,
+                                ErrorCallbackType ErrorCallback) {
+  MIToken Token;
+  Src = lexMIToken(Src, Token, [&](StringRef::iterator Loc, const Twine &Msg) {
+    ErrorCallback(Loc, Msg);
+  });
+  V = nullptr;
+
+  return ::parseIRValue(Token, PFS, V, ErrorCallback);
+}
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index b06e34a809f..9d9c12a9591 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -709,6 +709,7 @@ void MIPrinter::print(const MachineInstr &MI) {
   const auto *TRI = SubTarget.getRegisterInfo();
   assert(TRI && "Expected target register info");
   const auto *TII = SubTarget.getInstrInfo();
+  const auto *MIRF = MF->getTarget().getMIRFormatter();
   assert(TII && "Expected target instruction info");
   if (MI.isCFIInstruction())
     assert(MI.getNumOperands() == 1 && "Expected 1 operand in CFI instruction");
@@ -807,7 +808,7 @@ void MIPrinter::print(const MachineInstr &MI) {
     for (const auto *Op : MI.memoperands()) {
       if (NeedComma)
         OS << ", ";
-      Op->print(OS, MST, SSNs, Context, &MFI, TII);
+      Op->print(OS, MST, SSNs, Context, &MFI, TII, MIRF);
       NeedComma = true;
     }
   }
@@ -856,7 +857,7 @@ void MIPrinter::print(const MachineInstr &MI, unsigned OpIdx,
     if (ShouldPrintRegisterTies && Op.isReg() && Op.isTied() && !Op.isDef())
       TiedOperandIdx = Op.getParent()->findTiedOperandIdx(OpIdx);
     const TargetIntrinsicInfo *TII = MI.getMF()->getTarget().getIntrinsicInfo();
-    Op.print(OS, MST, TypeToPrint, PrintDef, /*IsStandalone=*/false,
+    Op.print(OS, MST, TypeToPrint, OpIdx, PrintDef, /*IsStandalone=*/false,
              ShouldPrintRegisterTies, TiedOperandIdx, TRI, TII);
     break;
   }
@@ -874,6 +875,28 @@ void MIPrinter::print(const MachineInstr &MI, unsigned OpIdx,
   }
 }
 
+void MIRFormatter::printIRValue(raw_ostream &OS, const Value &V,
+                                ModuleSlotTracker &MST) {
+  if (isa<GlobalValue>(V)) {
+    V.printAsOperand(OS, /*PrintType=*/false, MST);
+    return;
+  }
+  if (isa<Constant>(V)) {
+    // Machine memory operands can load/store to/from constant value pointers.
+    OS << '`';
+    V.printAsOperand(OS, /*PrintType=*/true, MST);
+    OS << '`';
+    return;
+  }
+  OS << "%ir.";
+  if (V.hasName()) {
+    printLLVMNameWithoutPrefix(OS, V.getName());
+    return;
+  }
+  int Slot = MST.getCurrentFunction() ? MST.getLocalSlot(&V) : -1;
+  MachineOperand::printIRSlotNumber(OS, Slot);
+}
+
 void llvm::printMIR(raw_ostream &OS, const Module &M) {
   yaml::Output Out(OS);
   Out << const_cast<Module &>(M);
diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 16ae732169a..177fef80e2e 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -89,13 +89,15 @@ static void tryToGetTargetInfo(const MachineInstr &MI,
                                const TargetRegisterInfo *&TRI,
                                const MachineRegisterInfo *&MRI,
                                const TargetIntrinsicInfo *&IntrinsicInfo,
-                               const TargetInstrInfo *&TII) {
+                               const TargetInstrInfo *&TII,
+                               const MIRFormatter *&MIRF) {
 
   if (const MachineFunction *MF = getMFIfAvailable(MI)) {
     TRI = MF->getSubtarget().getRegisterInfo();
     MRI = &MF->getRegInfo();
     IntrinsicInfo = MF->getTarget().getIntrinsicInfo();
     TII = MF->getSubtarget().getInstrInfo();
+    MIRF = MF->getTarget().getMIRFormatter();
   }
 }
 
@@ -1477,7 +1479,8 @@ void MachineInstr::print(raw_ostream &OS, ModuleSlotTracker &MST,
   const TargetRegisterInfo *TRI = nullptr;
   const MachineRegisterInfo *MRI = nullptr;
   const TargetIntrinsicInfo *IntrinsicInfo = nullptr;
-  tryToGetTargetInfo(*this, TRI, MRI, IntrinsicInfo, TII);
+  const MIRFormatter *MIRF = nullptr;
+  tryToGetTargetInfo(*this, TRI, MRI, IntrinsicInfo, TII, MIRF);
 
   if (isCFIInstruction())
     assert(getNumOperands() == 1 && "Expected 1 operand in CFI instruction");
@@ -1506,7 +1509,7 @@ void MachineInstr::print(raw_ostream &OS, ModuleSlotTracker &MST,
 
     LLT TypeToPrint = MRI ? getTypeToPrint(StartOp, PrintedTypes, *MRI) : LLT{};
     unsigned TiedOperandIdx = getTiedOperandIdx(StartOp);
-    MO.print(OS, MST, TypeToPrint, /*PrintDef=*/false, IsStandalone,
+    MO.print(OS, MST, TypeToPrint, StartOp, /*PrintDef=*/false, IsStandalone,
              ShouldPrintRegisterTies, TiedOperandIdx, TRI, IntrinsicInfo);
     ++StartOp;
   }
@@ -1561,7 +1564,7 @@ void MachineInstr::print(raw_ostream &OS, ModuleSlotTracker &MST,
     const unsigned OpIdx = InlineAsm::MIOp_AsmString;
     LLT TypeToPrint = MRI ? getTypeToPrint(OpIdx, PrintedTypes, *MRI) : LLT{};
     unsigned TiedOperandIdx = getTiedOperandIdx(OpIdx);
-    getOperand(OpIdx).print(OS, MST, TypeToPrint, /*PrintDef=*/true, IsStandalone,
+    getOperand(OpIdx).print(OS, MST, TypeToPrint, OpIdx, /*PrintDef=*/true, IsStandalone,
                             ShouldPrintRegisterTies, TiedOperandIdx, TRI,
                             IntrinsicInfo);
 
@@ -1600,7 +1603,7 @@ void MachineInstr::print(raw_ostream &OS, ModuleSlotTracker &MST,
       else {
         LLT TypeToPrint = MRI ? getTypeToPrint(i, PrintedTypes, *MRI) : LLT{};
         unsigned TiedOperandIdx = getTiedOperandIdx(i);
-        MO.print(OS, MST, TypeToPrint, /*PrintDef=*/true, IsStandalone,
+        MO.print(OS, MST, TypeToPrint, i, /*PrintDef=*/true, IsStandalone,
                  ShouldPrintRegisterTies, TiedOperandIdx, TRI, IntrinsicInfo);
       }
     } else if (isDebugLabel() && MO.isMetadata()) {
@@ -1611,7 +1614,7 @@ void MachineInstr::print(raw_ostream &OS, ModuleSlotTracker &MST,
       else {
         LLT TypeToPrint = MRI ? getTypeToPrint(i, PrintedTypes, *MRI) : LLT{};
         unsigned TiedOperandIdx = getTiedOperandIdx(i);
-        MO.print(OS, MST, TypeToPrint, /*PrintDef=*/true, IsStandalone,
+        MO.print(OS, MST, TypeToPrint, i, /*PrintDef=*/true, IsStandalone,
                  ShouldPrintRegisterTies, TiedOperandIdx, TRI, IntrinsicInfo);
       }
     } else if (i == AsmDescOp && MO.isImm()) {
@@ -1678,7 +1681,7 @@ void MachineInstr::print(raw_ostream &OS, ModuleSlotTracker &MST,
       if (MO.isImm() && isOperandSubregIdx(i))
         MachineOperand::printSubRegIdx(OS, MO.getImm(), TRI);
       else
-        MO.print(OS, MST, TypeToPrint, /*PrintDef=*/true, IsStandalone,
+        MO.print(OS, MST, TypeToPrint, i, /*PrintDef=*/true, IsStandalone,
                  ShouldPrintRegisterTies, TiedOperandIdx, TRI, IntrinsicInfo);
     }
   }
@@ -1737,7 +1740,7 @@ void MachineInstr::print(raw_ostream &OS, ModuleSlotTracker &MST,
     for (const MachineMemOperand *Op : memoperands()) {
       if (NeedComma)
         OS << ", ";
-      Op->print(OS, MST, SSNs, *Context, MFI, TII);
+      Op->print(OS, MST, SSNs, *Context, MFI, TII, MIRF);
       NeedComma = true;
     }
   }
diff --git a/llvm/lib/CodeGen/MachineOperand.cpp b/llvm/lib/CodeGen/MachineOperand.cpp
index 8b19501ec3c..5dd98467ba6 100644
--- a/llvm/lib/CodeGen/MachineOperand.cpp
+++ b/llvm/lib/CodeGen/MachineOperand.cpp
@@ -14,6 +14,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Analysis/Loads.h"
 #include "llvm/Analysis/MemoryLocation.h"
+#include "llvm/CodeGen/MIRFormatter.h"
 #include "llvm/CodeGen/MIRPrinter.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
@@ -458,28 +459,6 @@ static void printIRBlockReference(raw_ostream &OS, const BasicBlock &BB,
     OS << "<unknown>";
 }
 
-static void printIRValueReference(raw_ostream &OS, const Value &V,
-                                  ModuleSlotTracker &MST) {
-  if (isa<GlobalValue>(V)) {
-    V.printAsOperand(OS, /*PrintType=*/false, MST);
-    return;
-  }
-  if (isa<Constant>(V)) {
-    // Machine memory operands can load/store to/from constant value pointers.
-    OS << '`';
-    V.printAsOperand(OS, /*PrintType=*/true, MST);
-    OS << '`';
-    return;
-  }
-  OS << "%ir.";
-  if (V.hasName()) {
-    printLLVMNameWithoutPrefix(OS, V.getName());
-    return;
-  }
-  int Slot = MST.getCurrentFunction() ? MST.getLocalSlot(&V) : -1;
-  MachineOperand::printIRSlotNumber(OS, Slot);
-}
-
 static void printSyncScope(raw_ostream &OS, const LLVMContext &Context,
                            SyncScope::ID SSID,
                            SmallVectorImpl<StringRef> &SSNs) {
@@ -734,14 +713,15 @@ void MachineOperand::print(raw_ostream &OS, LLT TypeToPrint,
                            const TargetIntrinsicInfo *IntrinsicInfo) const {
   tryToGetTargetInfo(*this, TRI, IntrinsicInfo);
   ModuleSlotTracker DummyMST(nullptr);
-  print(OS, DummyMST, TypeToPrint, /*PrintDef=*/false, /*IsStandalone=*/true,
+  print(OS, DummyMST, TypeToPrint, None, /*PrintDef=*/false,
+        /*IsStandalone=*/true,
         /*ShouldPrintRegisterTies=*/true,
         /*TiedOperandIdx=*/0, TRI, IntrinsicInfo);
 }
 
 void MachineOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
-                           LLT TypeToPrint, bool PrintDef, bool IsStandalone,
-                           bool ShouldPrintRegisterTies,
+                           LLT TypeToPrint, Optional<unsigned> OpIdx, bool PrintDef,
+                           bool IsStandalone, bool ShouldPrintRegisterTies,
                            unsigned TiedOperandIdx,
                            const TargetRegisterInfo *TRI,
                            const TargetIntrinsicInfo *IntrinsicInfo) const {
@@ -802,9 +782,16 @@ void MachineOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
       OS << '(' << TypeToPrint << ')';
     break;
   }
-  case MachineOperand::MO_Immediate:
-    OS << getImm();
+  case MachineOperand::MO_Immediate: {
+    const MIRFormatter *Formatter = nullptr;
+    if (const MachineFunction *MF = getMFIfAvailable(*this))
+      Formatter = MF->getTarget().getMIRFormatter();
+    if (Formatter)
+      Formatter->printImm(OS, *getParent(), OpIdx, getImm());
+    else
+      OS << getImm();
     break;
+  }
   case MachineOperand::MO_CImmediate:
     getCImm()->printAsOperand(OS, /*PrintType=*/true, MST);
     break;
@@ -1070,7 +1057,8 @@ void MachineMemOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
                               SmallVectorImpl<StringRef> &SSNs,
                               const LLVMContext &Context,
                               const MachineFrameInfo *MFI,
-                              const TargetInstrInfo *TII) const {
+                              const TargetInstrInfo *TII,
+                              const MIRFormatter* MIRF) const {
   OS << '(';
   if (isVolatile())
     OS << "volatile ";
@@ -1111,7 +1099,7 @@ void MachineMemOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
 
   if (const Value *Val = getValue()) {
     OS << ((isLoad() && isStore()) ? " on " : isLoad() ? " from " : " into ");
-    printIRValueReference(OS, *Val, MST);
+    MIRFormatter::printIRValue(OS, *Val, MST);
   } else if (const PseudoSourceValue *PVal = getPseudoValue()) {
     OS << ((isLoad() && isStore()) ? " on " : isLoad() ? " from " : " into ");
     assert(PVal && "Expected a pseudo source value");
@@ -1144,15 +1132,20 @@ void MachineMemOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
       printLLVMNameWithoutPrefix(
           OS, cast<ExternalSymbolPseudoSourceValue>(PVal)->getSymbol());
       break;
-    default:
+    default: {
       // FIXME: This is not necessarily the correct MIR serialization format for
       // a custom pseudo source value, but at least it allows
       // -print-machineinstrs to work on a target with custom pseudo source
       // values.
-      OS << "custom ";
-      PVal->printCustom(OS);
+      OS << "custom \"";
+      if (MIRF)
+        MIRF->printCustomPseudoSourceValue(OS, MST, *PVal);
+      else
+        PVal->printCustom(OS);
+      OS << '\"';
       break;
     }
+    }
   }
   MachineOperand::printOperandOffset(OS, getOffset());
   if (getBaseAlignment() != getSize())
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index 6fd71393bf3..cbdcb93e60c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -480,7 +480,8 @@ static void printMemOperand(raw_ostream &OS, const MachineMemOperand &MMO,
   if (MF)
     MST.incorporateFunction(MF->getFunction());
   SmallVector<StringRef, 0> SSNs;
-  MMO.print(OS, MST, SSNs, Ctx, MFI, TII);
+  MMO.print(OS, MST, SSNs, Ctx, MFI, TII,
+            MF ? MF->getTarget().getMIRFormatter() : nullptr);
 }
 
 static void printMemOperand(raw_ostream &OS, const MachineMemOperand &MMO,
diff --git a/llvm/lib/Target/TargetMachine.cpp b/llvm/lib/Target/TargetMachine.cpp
index 97a1eb2f190..f070b143d5b 100644
--- a/llvm/lib/Target/TargetMachine.cpp
+++ b/llvm/lib/Target/TargetMachine.cpp
@@ -12,6 +12,7 @@
 
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/CodeGen/MIRFormatter.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalValue.h"
@@ -37,7 +38,9 @@ TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
     : TheTarget(T), DL(DataLayoutString), TargetTriple(TT), TargetCPU(CPU),
       TargetFS(FS), AsmInfo(nullptr), MRI(nullptr), MII(nullptr), STI(nullptr),
       RequireStructuredCFG(false), O0WantsFastISel(false),
-      DefaultOptions(Options), Options(Options) {}
+      DefaultOptions(Options), Options(Options) {
+  MIRF = std::make_unique<MIRFormatter>();
+}
 
 TargetMachine::~TargetMachine() = default;