[TableGen] RegisterInfo backend - Add abstraction layer between code generation logic and syntax output

[Rot127]

Summary

This patch introduces an abstraction layer for TableGen backends. It separates the code generation logic and the syntax string output into separated modules.
One module is the backend (RegisterInfo in this patch), the other PrinterLLVM.

The code generation stays in the TableGen backend. The syntax generation however is moved to PrinterLLVM, which writes the result to the output stream.
Whenever the backend has generated a piece of code it requests PrinterLLVM to write the syntax to the output stream.

Before this patch the TableGen backend generated the syntax on its own.
This had the disadvantage that no other languages, then the default C++ syntax, could be output easily.
With the separation of the code generation (backend) and syntax generation (PrinterLLVM) it is easier to output syntax of other languages.
It is also possible write a printer which emits only specific parts of the generated code.

A new printer only implements the methods of the PrinterLLVM it needs and emits its language syntax.

In this patch the RegisterInfo backend was refactored to use PrinterLLVM as output module.
If this gets upstreamed I can provide the refactor for the following modules in the next days:

• DecoderEmitter
• SubtargetInfo
• InstructionInfo
• AsmMatcher

For more background info and where this idea is coming from you can take a look at:

_Feedback implementation_
https://reviews.llvm.org/D136808

_Discussion in discourse.llvm.org_
https://discourse.llvm.org/t/comments-needed-for-refactoring-decoderemitter-tablegen-backend/65738

[Rot127]

To test the output after the refactor I used the following simple scripts:

Generate code files of all architectures.
This needs to be run twice. Once with a build on the main branch (remove the --printerLang=C++ option and the -new in the output filename).

And once with a build with this patch (add the -new in the output filename and --printerLang=C++ option` again)

#!/bin/bash
LLVM_PATH="<path>"
for ARCH in AArch64 AMDGPU ARC ARM AVR BPF CSKY DirectX Hexagon Lanai LoongArch M68k Mips MSP430 NVPTX PPC RISCV Sparc SPIRV SystemZ VE XCore; do
  echo $ARCH
  if [ $ARCH = "PPC" ]; then
    ARCH_D="PowerPC"
  else
    ARCH_D=$ARCH
  fi
  $LLVM_PATH/build/bin/llvm-tblgen --gen-register-info --printerLang=C++ -I $LLVM_PATH/llvm/include/ -I $LLVM_PATH/llvm/lib/Target/$ARCH_D/ -o $LLVM_PATH/tblgen-comparisons/reginfo/$ARCH-new.inc $LLVM_PATH/llvm/lib/Target/$ARCH_D/$ARCH.td
done

Then diffing <Arch>.inc and <Arch>-new.inc with

#!/bin/bash
LLVM_PATH="<path>"
for ARCH in AArch64 AMDGPU ARC ARM AVR BPF CSKY DirectX Hexagon Lanai LoongArch M68k Mips MSP430 NVPTX PPC RISCV Sparc SPIRV SystemZ VE XCore; do
  echo $ARCH
  diff $LLVM_PATH/tblgen-comparisons/reginfo/$ARCH.inc $LLVM_PATH/tblgen-comparisons/reginfo/$ARCH-new.inc
  echo $ARCH DONE
done

[0x59616e]

I like your idea, but I'm not a big fan of the code structure. It seems that we have to add a plethora of virtual functions for every backend in a single PrinterInterface class ? Wouldn't this break the 'open-close principle' and 'Interface segregation principle' ?

[Rot127]

In D138323#3948239, @0x59616e wrote:

Wouldn't this break the 'open-close principle' and 'Interface segregation principle' ?

Indeed it does. How about removing the PrinterInterface and make the PrinterLLVM the base class for all extensions (and mark its methods as virtual). Other Printers inherit from PrinterLLVM and override the methods needed?
This wouldn't be a big change, but also keep the printing logic in one place and not spread around the backends.

[Rot127]

Removes the PrinterInterface. New language printer should simply inherit from PrinterLLVM.

[arsenm]

llvm/utils/TableGen/Printer.h

74

Single quotes

100

Should use StringRef for all these const string parameters

llvm/utils/TableGen/PrinterLLVM.cpp

1419

Don't need a separate OS << on each line, can just break the one literal across multiple lines

[rovka]

In D138323#3949485, @Rot127 wrote:

In D138323#3948239, @0x59616e wrote:

Wouldn't this break the 'open-close principle' and 'Interface segregation principle' ?

Indeed it does. How about removing the PrinterInterface and make the PrinterLLVM the base class for all extensions (and mark its methods as virtual). Other Printers inherit from PrinterLLVM and override the methods needed?
This wouldn't be a big change, but also keep the printing logic in one place and not spread around the backends.

I too have concerns about the design here. I'd rather see smaller, more specific classes, e.g. a RegEmitterPrinter abstract base class which can then be inherited by a RegEmitterCPPPrinter(*) and other similar RegEmitter<Lang>Printer. Having the printer for a non-C++ language inherit from the C++ printer seems suspicious - what happens if you only override a subset of the virtuals? Do you get random bursts of C++ code in your output? Using an abstract base class seems like a better choice since then if you forget to override a method (of if one is added to the base class and the subclasses aren't updated) then things should explode in an easy-to-understand/fix way.

Speaking of random bursts of C++ code, how do you handle TableGen backends that allow C++ snippets to be embedded (e.g. for the instruction selection, assuming the docs are up to date)?

Would be nice to get a few more opinions about this before reworking the whole patch :)

(*) We could also have a CommonCPPPrinter (maybe with a better name) that contains things that are the same for all the backends, e.g. emitNamespace and other things like that (although I guess that can be in a later patch).

llvm/utils/TableGen/Printer.h

82

Nit: Would be clearer to just have emitBeginNamespace and emitEndNamespace. Ditto below for emitIncludeToggle.

llvm/utils/TableGen/RegisterInfoEmitter.cpp

787

Nit: This looks unrelated, you should commit it separately.

llvm/utils/TableGen/SequenceToOffsetTable.h

115

I'd rather extract the printing code for this into a printer too.

[Rot127]

Thanks for the feedback so far!

In D138323#4050804, @rovka wrote:

I'd rather see smaller, more specific classes, e.g. a RegEmitterPrinter abstract base class which can then be inherited by a RegEmitterCPPPrinter(*) and other similar RegEmitter<Lang>Printer.

The disadvantage with a Printer class per backend is that we have ~2+ files for each backend. So quite a lot.
Although this might not so bad if each backend is moved to its own directory. Just like GlobalISel.

... what happens if you only override a subset of the virtuals? Do you get random bursts of C++ code in your output?

Personally I don't see the danger of unexpected C++ output.
If an introduction document is added how to add a new language Printer (regardless of the design I will definitely add one), it should be clear that all methods for a backend must be overriden.

Using an abstract base class seems like a better choice since then if you forget to override a method (of if one is added to the base class and the subclasses aren't updated) then things should explode in an easy-to-understand/fix way.

The abstract class version was the first implementation I added here. If we agree on backend specific printer classes I would like to go back to this as well.
But with a single Printer for all backends it would force each new language Printer to override methods for other backends as well. Although it only needs one.

(*) We could also have a CommonCPPPrinter (maybe with a better name) that contains things that are the same for all the backends, e.g. emitNamespace and other things like that (although I guess that can be in a later patch).

If each backend gets its own printer class they could simply inherit from such a PrinterCommon or PrinterBase.
So something like : PrinterBase <---- PrinterBackendX <---- PrinterLangY?

Speaking of random bursts of C++ code, how do you handle TableGen backends that allow C++ snippets to be embedded (e.g. for the instruction selection, assuming the docs are up to date)?

I haven't looked at it because for the Capstone use case we only needed the backends listed on top to be honest.
But I'll look into it and report back.

I'd rather extract the printing code for this into a printer too. (The comment to SequenceToOffsetTable.h)

Of cause. But SequenceToOffsetTable is used in a yet not refactored backend. So I left it there for the time being. But I agree that classes like this should be integrated into the Printer.

Would be nice to get a few more opinions about this before reworking the whole patch :)

Absolutely agree :)

[nhaehnle]

I appreciate your desire to extract useful information, but I think this is fundamentally the wrong approach to take.

The interface implied by PrintLLVM is at the wrong level of abstraction: will users who want to extract information really want to extract all this information, and if they do, will they want to do it in the same order and along the same hierarchy? What works for C++ might not work for another language and for another context. Another user of the information here is unlikely to need the exact set that is provided by the existing printer. And so on. In essence, the interface is exactly the wrong way around.

The code is already structured into a "database" part (CodeGenTarget) and a "printer" part, and the printer is quite intrinsically tied to C++ structures in many places. Ideally, you'd just use CodeGenTarget from a new printer, and potentially augment that class with additional features you may need.

The other meta problem here is that you're changing the code to be a lot less maintainable without an easily understandable in-tree motivation. For example: let's say we land this change. Soon after, anybody who looks at the code with these changes will immediately (and correctly) conclude that all those virtual methods aren't necessary and ought to be removed. Therefore, for out-of-tree purposes I would seriously urge you to just write a new printer that re-uses CodeGenTarget.

This would be different if you had an in-tree motivation for the changes.

llvm/utils/TableGen/SequenceToOffsetTable.h

115

I disagree. That's additional complexity that simply isn't needed at this stage.

[Rot127]

Thank you for the feedback!
Its my first time with LLVM so your critique is very valuable for me.

In D138323#4061704, @nhaehnle wrote:

... will users who want to extract information really want to extract all this information,

Please see the example with the DecoderEmitter below. In which case the answer would be yes.

... and if they do, will they want to do it in the same order and along the same hierarchy? What works for C++ might not work for another language and for another context.

Since the Printer controls the complete output, the hierarchy and order problem could be solved by it. Although it probably ends up in complicated printers.
So yes, non C like languages couldn't be printed in an elegant way.

Ideally, you'd just use CodeGenTarget from a new printer, and potentially augment that class with additional features you may need.

I agree that this is the way to go for backends which emit mostly unprocessed information from the CodeGenTarget.
But it is complicated for backends like the DecoderEmitter.
This backend generates a state machine for decoding instructions and emits the C++ version of it. But the whole state machine generation logic is mixed together with the code printing.
So it is not possible to build a printer solely on top of the state-machine generation logic.

And maintaining an altered copy of it is maintenance heavy.

Would you say that in such a case this abstraction would be of use? Or should the state-machine generation be move to the CodeGenTarget in you opinion (as target-independent code generation algorithm I guess)?

My underling problem is that the Emitter backends don't just emit syntax. But quite often process (sometimes heavily) the information given by CodeGenTarget and the Records but don't make the result accessible.

The other meta problem here is that you're changing the code to be a lot less maintainable without an easily understandable in-tree motivation. For example: let's say we land this change. Soon after, anybody who looks at the code with these changes will immediately (and correctly) conclude that all those virtual methods aren't necessary and ought to be removed. Therefore, for out-of-tree purposes I would seriously urge you to just write a new printer that re-uses CodeGenTarget.

I could of cause add a Printer for C, but this is probably irrelevant as long as the other points are not solved.

[nhaehnle]

Ideally, you'd just use CodeGenTarget from a new printer, and potentially augment that class with additional features you may need.

I agree that this is the way to go for backends which emit mostly unprocessed information from the CodeGenTarget.
But it is complicated for backends like the DecoderEmitter.
This backend generates a state machine for decoding instructions and emits the C++ version of it. But the whole state machine generation logic is mixed together with the code printing.
So it is not possible to build a printer solely on top of the state-machine generation logic.

And maintaining an altered copy of it is maintenance heavy.

Would you say that in such a case this abstraction would be of use? Or should the state-machine generation be move to the CodeGenTarget in you opinion (as target-independent code generation algorithm I guess)?

My underling problem is that the Emitter backends don't just emit syntax. But quite often process (sometimes heavily) the information given by CodeGenTarget and the Records but don't make the result accessible.

Yes, that's indeed an issue for what you're trying to do. IMHO it is also an issue for the maintainability of these backends as they are today. So I'd say we should try to separate the state-machine generation code from the printing code. It could be moved to CodeGenTarget, though I think it'd be better to keep things slightly more modular and instead split up the current DecoderEmitter into parts:

• A Decoder class contains all the state-machine description. Think of it as an "intermediate representation for a decoder/disassembler": it contains the data describing the decoder, but essentially no logic.
• A separate createDecoder function creates a Decoder given a CodeGenTarget
• The emitDecoder function writes out the generated C++ for a given Decoder object

Does that make sense to you?

[Rot127]

In D138323#4072561, @nhaehnle wrote:

Yes, that's indeed an issue for what you're trying to do. IMHO it is also an issue for the maintainability of these backends as they are today. So I'd say we should try to separate the state-machine generation code from the printing code. It could be moved to CodeGenTarget, though I think it'd be better to keep things slightly more modular and instead split up the current DecoderEmitter into parts:

• A Decoder class contains all the state-machine description. Think of it as an "intermediate representation for a decoder/disassembler": it contains the data describing the decoder, but essentially no logic.
• A separate createDecoder function creates a Decoder given a CodeGenTarget
• The emitDecoder function writes out the generated C++ for a given Decoder object

Does that make sense to you?

This is certainly one way of doing it. This would also fit loosely the current working (the the current DecoderEmitter works like this).

But personally I would start at a more fundamental redesign.

Preparation

1. Enumerate backends which:
   • processes CodeGen information into more complex structures (e.g. decoder tables, lists of certain operands etc.).
   • mix up code generation and code emitting.
2. For each backend identify what self-contained InfoBlocks (I lag a better name here) it produces
   • RegisterInfoEmitter: Produces register enums, Subregister information tables, Register classes info tables, algorithms to get register names from the enums etc.
   • AsmWriter: Instruction mnemonic tables, alias mnemonics, Mnemonic selection logic etc.
   • DecoderEmitter: Produces a complete decoder, with all its tables and state-machine traversal algorithms. ...

The design

The new design would consists of small modules which generate only one InfoBlock (a single enum, a single table, code to traverse a certain table).
Additionally we add a controller module which triggers the generation of different blocks.

Complicated InfoBlocks which consists effectively of multiple other InfoBlocks (e.g. the decoder needs instruction enums, the state machine algorithm, state machine tables etc.)
can have dependencies to other InfoBlocks.

For each InfoBlock I imagine a data structure like this:

struct {
  Name; // Unique name/ID of this information
  Data;  // The data, e.g. a vector with strings representing a register name enum or more complex stuff.
  DataType;  // Enumeration, Algorithm/Code, Table, StateMachine ...
  Dependencies;  // List of Names/IDs this InfoBlock depends on.

  void genInfo(CodeGenTarget Target, vector<InfoBlock> Dependencies); // Generates the information and stores it in `Data`.
}

Now, our new controller module would get a list of InfoBlocks. It triggers the generation of them and their dependencies.

If they need to be emitted, an Emitter can get those InfoBlocks and simply print them, without manipulating the data further. It can do this in whatever order, hierarchy and syntax it likes.

*Pros*

• Fine grained control what information is generated.
• InfoBlock generator modules can be selected for build at will, no huge backends anymore (seems to be a problem, see: https://discourse.llvm.org/t/issues-in-llvm-tblgen-high-parallelized-build/68037/16).
• Non Emitter backends can use the InfoBlock data as well.
• Most of the InfoBlock generation modules should be very small.

*Cons*

• What counts as self-containing InfoBlock?
• Danger of very similar modules. E.g. in the long run several InfoBlocks could end up generating *almost* the same information but not quite.
• It is a ton of work.

With all that said, what do you think?

The very last point ("It is a ton of work") would be a problem for me. I decided because of that to design this patch as it is. Simply because I need to be done at some point.

So just to make sure, will the refactor (as in the diff here) has any future to get upstreamed?
Or will only a more fundamental change (moving logic to CodeGentTarget) be accepted?

[Rot127]

Since LLVM16 is now released, I wondered if anyone has more comments regarding my proposals to untangle the emitters.
Because if anyone sees this as useful I would be happy to sum up the discussion here and move it into the forum.

@nhaehnle I assume this revision will not be accepted?

llvm/utils/TableGen/CMakeLists.txt

add_tablegen(llvm-tblgen LLVM
   InfoByHwMode.cpp
   InstrInfoEmitter.cpp
   InstrDocsEmitter.cpp
   IntrinsicEmitter.cpp
   OptEmitter.cpp
   OptParserEmitter.cpp
   OptRSTEmitter.cpp
   PredicateExpander.cpp
+  PrinterLLVM.cpp
   PseudoLoweringEmitter.cpp
   CompressInstEmitter.cpp
   RegisterBankEmitter.cpp
   RegisterInfoEmitter.cpp
   SDNodeProperties.cpp
   SearchableTableEmitter.cpp
   SubtargetEmitter.cpp
   SubtargetFeatureInfo.cpp

llvm/utils/TableGen/Printer.h

+//===--------------- Printer.h - Printer Interface --------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_UTILS_TABLEGEN_PRINTER_H
+#define LLVM_UTILS_TABLEGEN_PRINTER_H
+
+#include "CodeGenRegisters.h"
+#include "CodeGenTarget.h"
+#include "PrinterTypes.h"
+#include "RegisterInfoEmitterTypes.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+
+class PrinterBitVectorEmitter {
+  BitVector Values;
+
+public:
+  virtual void add(unsigned V);
+  virtual void print(raw_ostream &OS);
+};
+
+void printBitVectorAsHex(raw_ostream &OS, const BitVector &Bits,
+                         unsigned Width);
+
+//==============================
+//
+// Implementation: LLVM
+//
+//==============================
+
+/// Interface for printing the generated code.
+/// Every string which will be in the generated code of a backend originates
+/// from here.
+///
+/// It also is the only class which writes directly into the output stream for
+/// the backend.
+///
+/// This class has methods for all classes of backends which emit generated
+/// code. If a backend currently does not emit the code in a language you need
+/// you simply inherit this class and implement the relevant methods.
+///
+/// Printer implementation of LLVM.
+/// This is the default printer for all backends.
+///
+/// Output language: C++
+class PrinterLLVM {
+
+private:
+  formatted_raw_ostream &OS;
+
+public:
+  PrinterLLVM(formatted_raw_ostream &OS);
+
+  virtual ~PrinterLLVM();
+
+  static PrinterLanguage getLanguage();
+
+  virtual void flushOS() const { OS.flush(); }
+
+  //--------------------------
+  // General printing methods
+  //--------------------------
+
+  virtual void emitNewline(unsigned Count) const {
+    for (unsigned I = Count; I > 0; --I)
+      OS << "\n";
+  }
+  virtual void emitString(std::string const &Str) const { OS << Str; }
+
+  //--------------------------
+  // General printing methods
+  //--------------------------
+
+  virtual void emitNamespace(std::string const &Name, bool Begin,
+                             std::string const &Comment = "") const;
+  virtual void emitIncludeToggle(std::string const &Name, bool Begin) const;
+
+  //------------------------
+  // Backend: RegisterInfo
+  //------------------------
+
+  virtual void regInfoEmitSourceFileHeader(std::string const &Desc) const;
+  virtual void regInfoEmitEnums(CodeGenTarget const &Target,
+                                CodeGenRegBank const &Bank) const;
+  virtual void
+  regInfoEmitRegDiffLists(std::string const TargetName,
+                          SequenceToOffsetTable<DiffVec> const &DiffSeqs) const;
+  virtual void regInfoEmitLaneMaskLists(
+      std::string const TargetName,
+      SequenceToOffsetTable<MaskVec> const &DiffSeqs) const;
+  virtual void regInfoEmitSubRegIdxLists(
+      std::string const TargetName,
+      SequenceToOffsetTable<SubRegIdxVec, deref<std::less<>>> const
+          &SubRegIdxSeqs) const;
+  virtual void regInfoEmitSubRegIdxSizes(
+      std::string const TargetName,
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices) const;
+  virtual void regInfoEmitSubRegStrTable(
+      std::string const TargetName,
+      SequenceToOffsetTable<std::string> const &RegStrings) const;
+  virtual void regInfoEmitRegDesc(
+      SequenceToOffsetTable<MaskVec> const &LaneMaskSeqs,
+      std::deque<CodeGenRegister> const &Regs,
+      SequenceToOffsetTable<SubRegIdxVec, deref<std::less<>>> const
+          &SubRegIdxSeqs,
+      SequenceToOffsetTable<DiffVec> const &DiffSeqs,
+      SmallVector<SubRegIdxVec, 4> const &SubRegIdxLists,
+      SmallVector<DiffVec, 4> const &SubRegLists,
+      SmallVector<DiffVec, 4> const &SuperRegLists,
+      SmallVector<DiffVec, 4> const &RegUnitLists,
+      SmallVector<unsigned, 4> const &RegUnitInitScale,
+      SmallVector<MaskVec, 4> const &RegUnitLaneMasks,
+      SequenceToOffsetTable<std::string> const &RegStrings) const;
+  virtual void regInfoEmitRegUnitRoots(std::string const TargetName,
+                                       CodeGenRegBank const &RegBank) const;
+  virtual void
+  regInfoEmitRegClasses(std::list<CodeGenRegisterClass> const &RegClasses,
+                        SequenceToOffsetTable<std::string> &RegClassStrings,
+                        CodeGenTarget const &Target) const;
+  virtual void regInfoEmitStrLiteralRegClasses(
+      std::string const TargetName,
+      SequenceToOffsetTable<std::string> const &RegClassStrings) const;
+  virtual void regInfoEmitMCRegClassesTable(
+      std::string const TargetName,
+      std::list<CodeGenRegisterClass> const &RegClasses,
+      SequenceToOffsetTable<std::string> &RegClassStrings) const;
+  virtual void
+  regInfoEmitRegEncodingTable(std::string const TargetName,
+                              std::deque<CodeGenRegister> const &Regs) const;
+  virtual void regInfoEmitMCRegInfoInit(
+      std::string const TargetName, CodeGenRegBank const &RegBank,
+      std::deque<CodeGenRegister> const &Regs,
+      std::list<CodeGenRegisterClass> const &RegClasses,
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices) const;
+  virtual void regInfoEmitInfoDwarfRegs(StringRef const &Namespace,
+                                        DwarfRegNumsVecTy &DwarfRegNums,
+                                        unsigned MaxLength, bool IsCtor) const;
+  virtual void regInfoEmitInfoDwarfRegsRev(StringRef const &Namespace,
+                                           DwarfRegNumsVecTy &DwarfRegNums,
+                                           unsigned MaxLength,
+                                           bool IsCtor) const;
+  virtual void regInfoEmitInfoRegMapping(StringRef const &Namespace,
+                                         unsigned MaxLength, bool IsCtor) const;
+  virtual void regInfoEmitHeaderIncludes() const;
+  virtual void regInfoEmitHeaderExternRegClasses(
+      std::list<CodeGenRegisterClass> const &RegClasses) const;
+  virtual void regInfoEmitHeaderDecl(std::string const &TargetName,
+                                     std::string const &ClassName,
+                                     bool SubRegsPresent,
+                                     bool DeclareGetPhysRegBaseClass) const;
+  virtual void
+  regInfoEmitExternRegClassesArr(std::string const &TargetName) const;
+  virtual void regInfoEmitVTSeqs(
+      SequenceToOffsetTable<std::vector<MVT::SimpleValueType>> const &VTSeqs)
+      const;
+  virtual void regInfoEmitSubRegIdxTable(
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices) const;
+  virtual void regInfoEmitRegClassInfoTable(
+      std::list<CodeGenRegisterClass> const &RegClasses,
+      SequenceToOffsetTable<std::vector<MVT::SimpleValueType>> const &VTSeqs,
+      CodeGenHwModes const &CGH, unsigned NumModes) const;
+  virtual void regInfoEmitSubClassMaskTable(
+      std::list<CodeGenRegisterClass> const &RegClasses,
+      SmallVector<IdxList, 8> &SuperRegIdxLists,
+      SequenceToOffsetTable<IdxList, deref<std::less<>>> &SuperRegIdxSeqs,
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices,
+      BitVector &MaskBV) const;
+  virtual void regInfoEmitSuperRegIdxSeqsTable(
+      SequenceToOffsetTable<IdxList, deref<std::less<>>> const &SuperRegIdxSeqs)
+      const;
+  virtual void regInfoEmitSuperClassesTable(
+      std::list<CodeGenRegisterClass> const &RegClasses) const;
+  virtual void
+  regInfoEmitRegClassMethods(std::list<CodeGenRegisterClass> const &RegClasses,
+                             std::string const &TargetName) const;
+  virtual void regInfomitRegClassInstances(
+      std::list<CodeGenRegisterClass> const &RegClasses,
+      SequenceToOffsetTable<IdxList, deref<std::less<>>> const &SuperRegIdxSeqs,
+      SmallVector<IdxList, 8> const &SuperRegIdxLists,
+      std::string const &TargetName) const;
+  virtual void regInfoEmitRegClassTable(
+      std::list<CodeGenRegisterClass> const &RegClasses) const;
+  virtual void
+  regInfoEmitCostPerUseTable(std::vector<unsigned> const &AllRegCostPerUse,
+                             unsigned NumRegCosts) const;
+  virtual void
+  regInfoEmitInAllocatableClassTable(llvm::BitVector const &InAllocClass) const;
+  virtual void regInfoEmitRegExtraDesc(std::string const &TargetName,
+                                       unsigned NumRegCosts) const;
+  virtual void regInfoEmitSubClassSubRegGetter(
+      std::string const &ClassName, unsigned SubRegIndicesSize,
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices,
+      std::list<CodeGenRegisterClass> const &RegClasses,
+      CodeGenRegBank &RegBank) const;
+  virtual void regInfoEmitRegClassWeight(CodeGenRegBank const &RegBank,
+                                         std::string const &ClassName) const;
+  virtual void regInfoEmitRegUnitWeight(CodeGenRegBank const &RegBank,
+                                        std::string const &ClassName,
+                                        bool RegUnitsHaveUnitWeight) const;
+  virtual void regInfoEmitGetNumRegPressureSets(std::string const &ClassName,
+                                                unsigned NumSets) const;
+  virtual void regInfoEmitGetRegPressureTables(CodeGenRegBank const &RegBank,
+                                               std::string const &ClassName,
+                                               unsigned NumSets) const;
+  virtual void regInfoEmitRCSetsTable(
+      std::string const &ClassName, unsigned NumRCs,
+      SequenceToOffsetTable<std::vector<int>> const &PSetsSeqs,
+      std::vector<std::vector<int>> const &PSets) const;
+  virtual void regInfoEmitGetRegUnitPressureSets(
+      SequenceToOffsetTable<std::vector<int>> const &PSetsSeqs,
+      CodeGenRegBank const &RegBank, std::string const &ClassName,
+      std::vector<std::vector<int>> const &PSets) const;
+  virtual void regInfoEmitExternTableDecl(std::string const &TargetName) const;
+  virtual void
+  regInfoEmitRegClassInit(std::string const &TargetName,
+                          std::string const &ClassName,
+                          CodeGenRegBank const &RegBank,
+                          std::list<CodeGenRegisterClass> const &RegClasses,
+                          std::deque<CodeGenRegister> const &Regs,
+                          unsigned SubRegIndicesSize) const;
+  virtual void regInfoEmitSaveListTable(Record const *CSRSet,
+                                        SetTheory::RecVec const *Regs) const;
+  virtual void regInfoEmitRegMaskTable(std::string const &CSRSetName,
+                                       BitVector &Covered) const;
+  virtual void
+  regInfoEmitIsConstantPhysReg(std::deque<CodeGenRegister> const &Regs,
+                               std::string const &ClassName) const;
+  virtual void regInfoEmitGetRegMasks(std::vector<Record *> const &CSRSets,
+                                      std::string const &ClassName) const;
+  virtual void regInfoEmitGPRCheck(
+      std::string const &ClassName,
+      std::list<CodeGenRegisterCategory> const &RegCategories) const;
+  virtual void regInfoEmitFixedRegCheck(
+      std::string const &ClassName,
+      std::list<CodeGenRegisterCategory> const &RegCategories) const;
+  virtual void regInfoEmitArgRegCheck(
+      std::string const &ClassName,
+      std::list<CodeGenRegisterCategory> const &RegCategories) const;
+  virtual void regInfoEmitGetRegMaskNames(std::vector<Record *> const &CSRSets,
+                                          std::string const &ClassName) const;
+  virtual void regInfoEmitGetFrameLowering(std::string const &TargetName) const;
+  virtual void
+  regInfoEmitComposeSubRegIndicesImplHead(std::string const &ClName) const;
+  virtual void regInfoEmitComposeSubRegIndicesImplBody(
+      SmallVector<SmallVector<CodeGenSubRegIndex *, 4>, 4> const &Rows,
+      unsigned SubRegIndicesSize, SmallVector<unsigned, 4> const &RowMap) const;
+  virtual void regInfoEmitLaneMaskComposeSeq(
+      SmallVector<SmallVector<MaskRolPair, 1>, 4> const &Sequences,
+      SmallVector<unsigned, 4> const &SubReg2SequenceIndexMap,
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices) const;
+  virtual void regInfoEmitComposeSubRegIdxLaneMask(
+      std::string const &ClName,
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices) const;
+  virtual void regInfoEmitComposeSubRegIdxLaneMaskRev(
+      std::string const &ClName,
+      std::deque<CodeGenSubRegIndex> const &SubRegIndices) const;
+  virtual void regInfoEmitRegBaseClassMapping(
+      std::string const &ClassName,
+      SmallVector<const CodeGenRegisterClass *> const BaseClasses,
+      std::vector<uint8_t> const Mapping) const;
+};
+
+#endif // LLVM_UTILS_TABLEGEN_PRINTER_H
+
+} // end namespace llvm

llvm/utils/TableGen/PrinterLLVM.cpp

+//===------------ PrinterLLVM.cpp - LLVM C++ code printer -----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Implementation of the LLVM C++ printer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Printer.h"
+#include "llvm/TableGen/TableGenBackend.h"
+
+namespace llvm {
+
+cl::OptionCategory PrinterLang("Select output language of backends");
+
+static cl::opt<std::string>
+    PrinterLangOpt("printerLang", cl::init("C++"),
+                   cl::desc("Output language options: \"C++\" (default), "
+                            "\"CCS\" (C Capstone style)"),
+                   cl::cat(PrinterLang));
+
+// Print a BitVector as a sequence of hex numbers using a little-endian mapping.
+// Width is the number of bits per hex number.
+void printBitVectorAsHex(raw_ostream &OS, const BitVector &Bits,
+                         unsigned Width) {
+  assert(Width <= 32 && "Width too large");
+  unsigned const Digits = (Width + 3) / 4;
+  for (unsigned I = 0, E = Bits.size(); I < E; I += Width) {
+    unsigned Value = 0;
+    for (unsigned J = 0; J != Width && I + J != E; ++J)
+      Value |= Bits.test(I + J) << J;
+    OS << format("0x%0*x, ", Digits, Value);
+  }
+}
+
+void PrinterBitVectorEmitter::add(unsigned V) {
+  if (V >= Values.size())
+    Values.resize(((V / 8) + 1) * 8); // Round up to the next byte.
+  Values[V] = true;
+}
+
+void PrinterBitVectorEmitter::print(raw_ostream &OS) {
+  printBitVectorAsHex(OS, Values, 8);
+}
+
+//
+// General PrinterLLVM methods
+//
+
+PrinterLLVM::PrinterLLVM(formatted_raw_ostream &OS) : OS(OS) {}
+PrinterLLVM::~PrinterLLVM() {}
+
+PrinterLanguage PrinterLLVM::getLanguage() {
+  if (PrinterLangOpt == "C++")
+    return PRINTER_LANG_CPP;
+  if (PrinterLangOpt == "CCS")
+    return PRINTER_LANG_CAPSTONE_C;
+
+  PrintFatalNote("Unkown output language for printer selected.");
+}
+
+/// Prints `namespace <name> {` and `} // end namespace <name>` to the output
+/// stream. If Name == "" it emits an anonymous namespace.
+void PrinterLLVM::emitNamespace(std::string const &Name, bool Begin,
+                                std::string const &Comment) const {
+  if (Begin) {
+    OS << "namespace " << Name;
+    std::string const Bracket = (Name == "" ? "{" : " {");
+    if (Comment != "")
+      OS << Bracket << " // " << Comment << "\n";
+    else
+      OS << Bracket << "\n\n";
+    return;
+  }
+
+  if (Name == "") {
+    OS << "} // end anonymous namespace\n\n";
+  } else {
+    OS << "} // end namespace " << Name << "\n\n";
+  }
+}
+
+/// Prints
+/// ```
+/// #ifdef <Name>
+/// #undef <Name>
+/// ```
+/// and
+/// `#endif // <Name>`
+/// Used to control inclusion of a code block via a macro definition.
+void PrinterLLVM::emitIncludeToggle(std::string const &Name, bool Begin) const {
+  if (Begin) {
+    OS << "\n#ifdef " << Name << "\n";
+    OS << "#undef " << Name << "\n\n";
+  } else {
+    OS << "#endif // " << Name << "\n\n";
+  }
+}
+
+void PrinterLLVM::regInfoEmitSourceFileHeader(std::string const &Desc) const {
+  emitSourceFileHeader(Desc, OS);
+}
+
+// runEnums - Print out enum values for all of the registers.
+void PrinterLLVM::regInfoEmitEnums(CodeGenTarget const &Target,
+                                   CodeGenRegBank const &Bank) const {
+  const auto &Registers = Bank.getRegisters();
+
+  // Register enums are stored as uint16_t in the tables. Make sure we'll fit.
+  assert(Registers.size() <= 0xffff && "Too many regs to fit in tables");
+
+  StringRef const Namespace =
+      Registers.front().TheDef->getValueAsString("Namespace");
+
+  OS << "\n#ifdef GET_REGINFO_ENUM\n";
+  OS << "#undef GET_REGINFO_ENUM\n\n";
+
+  OS << "namespace llvm {\n\n";
+
+  OS << "class MCRegisterClass;\n"
+     << "extern const MCRegisterClass " << Target.getName()
+     << "MCRegisterClasses[];\n\n";
+
+  if (!Namespace.empty())
+    OS << "namespace " << Namespace << " {\n";
+  OS << "enum {\n  NoRegister,\n";
+
+  for (const auto &Reg : Registers)
+    OS << "  " << Reg.getName() << " = " << Reg.EnumValue << ",\n";
+  assert(Registers.size() == Registers.back().EnumValue &&
+         "Register enum value mismatch!");
+  OS << "  NUM_TARGET_REGS // " << Registers.size() + 1 << "\n";
+  OS << "};\n";
+  if (!Namespace.empty())
+    OS << "} // end namespace " << Namespace << "\n";
+
+  const auto &RegisterClasses = Bank.getRegClasses();
+  if (!RegisterClasses.empty()) {
+
+    // RegisterClass enums are stored as uint16_t in the tables.
+    assert(RegisterClasses.size() <= 0xffff &&
+           "Too many register classes to fit in tables");
+
+    OS << "\n// Register classes\n\n";
+    if (!Namespace.empty())
+      OS << "namespace " << Namespace << " {\n";
+    OS << "enum {\n";
+    for (const auto &RC : RegisterClasses)
+      OS << "  " << RC.getName() << "RegClassID"
+         << " = " << RC.EnumValue << ",\n";
+    OS << "\n};\n";
+    if (!Namespace.empty())
+      OS << "} // end namespace " << Namespace << "\n\n";
+  }
+
+  const std::vector<Record *> &RegAltNameIndices =
+      Target.getRegAltNameIndices();
+  // If the only definition is the default NoRegAltName, we don't need to
+  // emit anything.
+  if (RegAltNameIndices.size() > 1) {
+    OS << "\n// Register alternate name indices\n\n";
+    if (!Namespace.empty())
+      OS << "namespace " << Namespace << " {\n";
+    OS << "enum {\n";
+    for (unsigned I = 0, E = RegAltNameIndices.size(); I != E; ++I)
+      OS << "  " << RegAltNameIndices[I]->getName() << ",\t// " << I << "\n";
+    OS << "  NUM_TARGET_REG_ALT_NAMES = " << RegAltNameIndices.size() << "\n";
+    OS << "};\n";
+    if (!Namespace.empty())
+      OS << "} // end namespace " << Namespace << "\n\n";
+  }
+
+  auto &SubRegIndices = Bank.getSubRegIndices();
+  if (!SubRegIndices.empty()) {
+    OS << "\n// Subregister indices\n\n";
+    std::string const Namespace = SubRegIndices.front().getNamespace();
+    if (!Namespace.empty())
+      OS << "namespace " << Namespace << " {\n";
+    OS << "enum : uint16_t {\n  NoSubRegister,\n";
+    unsigned I = 0;
+    for (const auto &Idx : SubRegIndices)
+      OS << "  " << Idx.getName() << ",\t// " << ++I << "\n";
+    OS << "  NUM_TARGET_SUBREGS\n};\n";
+    if (!Namespace.empty())
+      OS << "} // end namespace " << Namespace << "\n\n";
+  }
+
+  OS << "// Register pressure sets enum.\n";
+  if (!Namespace.empty())
+    OS << "namespace " << Namespace << " {\n";
+  OS << "enum RegisterPressureSets {\n";
+  unsigned const NumSets = Bank.getNumRegPressureSets();
+  for (unsigned I = 0; I < NumSets; ++I) {
+    const RegUnitSet &RegUnits = Bank.getRegSetAt(I);
+    OS << "  " << RegUnits.Name << " = " << I << ",\n";
+  }
+  OS << "};\n";
+  if (!Namespace.empty())
+    OS << "} // end namespace " << Namespace << '\n';
+  OS << '\n';
+
+  OS << "} // end namespace llvm\n\n";
+  OS << "#endif // GET_REGINFO_ENUM\n\n";
+}
+
+void PrinterLLVM::regInfoEmitRegDiffLists(
+    std::string const TargetName,
+    SequenceToOffsetTable<DiffVec> const &DiffSeqs) const {
+  OS << "extern const MCPhysReg " << TargetName << "RegDiffLists[] = {\n";
+  DiffSeqs.emit(OS, [](raw_ostream &OS, uint16_t Val) { OS << Val; });
+  OS << "};\n\n";
+}
+
+static void regInfoPrintMask(raw_ostream &OS, LaneBitmask Val) {
+  OS << "LaneBitmask(0x" << PrintLaneMask(Val) << ')';
+}
+
+void PrinterLLVM::regInfoEmitLaneMaskLists(
+    std::string const TargetName,
+    SequenceToOffsetTable<MaskVec> const &LaneMaskSeqs) const {
+  OS << "extern const LaneBitmask " << TargetName << "LaneMaskLists[] = {\n";
+  LaneMaskSeqs.emit(OS, regInfoPrintMask, "LaneBitmask::getAll()");
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitSubRegIdxLists(
+    std::string const TargetName,
+    SequenceToOffsetTable<SubRegIdxVec, deref<std::less<>>> const
+        &SubRegIdxSeqs) const {
+  OS << "extern const uint16_t " << TargetName << "SubRegIdxLists[] = {\n";
+  SubRegIdxSeqs.emit(OS, [](raw_ostream &OS, const CodeGenSubRegIndex *Idx) {
+    OS << Idx->EnumValue;
+  });
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitSubRegIdxSizes(
+    std::string const TargetName,
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices) const {
+  OS << "extern const MCRegisterInfo::SubRegCoveredBits " << TargetName
+     << "SubRegIdxRanges[] = {\n";
+  OS << "  { " << (uint16_t)-1 << ", " << (uint16_t)-1 << " },\n";
+  for (const auto &Idx : SubRegIndices) {
+    OS << "  { " << Idx.Offset << ", " << Idx.Size << " },\t// "
+       << Idx.getName() << "\n";
+  }
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitSubRegStrTable(
+    std::string const TargetName,
+    SequenceToOffsetTable<std::string> const &RegStrings) const {
+  RegStrings.emitStringLiteralDef(OS, Twine("extern const char ") + TargetName +
+                                          "RegStrings[]");
+
+  OS << "extern const MCRegisterDesc " << TargetName
+     << "RegDesc[] = { // Descriptors\n";
+  OS << "  { " << RegStrings.get("") << ", 0, 0, 0, 0, 0 },\n";
+}
+
+void PrinterLLVM::regInfoEmitRegDesc(
+    SequenceToOffsetTable<MaskVec> const &LaneMaskSeqs,
+    std::deque<CodeGenRegister> const &Regs,
+    SequenceToOffsetTable<SubRegIdxVec, deref<std::less<>>> const
+        &SubRegIdxSeqs,
+    SequenceToOffsetTable<DiffVec> const &DiffSeqs,
+    SmallVector<SubRegIdxVec, 4> const &SubRegIdxLists,
+    SmallVector<DiffVec, 4> const &SubRegLists,
+    SmallVector<DiffVec, 4> const &SuperRegLists,
+    SmallVector<DiffVec, 4> const &RegUnitLists,
+    SmallVector<unsigned, 4> const &RegUnitInitScale,
+    SmallVector<MaskVec, 4> const &RegUnitLaneMasks,
+    SequenceToOffsetTable<std::string> const &RegStrings) const {
+  unsigned I = 0;
+  for (const auto &Reg : Regs) {
+    OS << "  { " << RegStrings.get(std::string(Reg.getName())) << ", "
+       << DiffSeqs.get(SubRegLists[I]) << ", " << DiffSeqs.get(SuperRegLists[I])
+       << ", " << SubRegIdxSeqs.get(SubRegIdxLists[I]) << ", "
+       << (DiffSeqs.get(RegUnitLists[I]) * 16 + RegUnitInitScale[I]) << ", "
+       << LaneMaskSeqs.get(RegUnitLaneMasks[I]) << " },\n";
+    ++I;
+  }
+  OS << "};\n\n"; // End of register descriptors...
+}
+
+void PrinterLLVM::regInfoEmitRegUnitRoots(std::string const TargetName,
+                                          CodeGenRegBank const &RegBank) const {
+  OS << "extern const MCPhysReg " << TargetName << "RegUnitRoots[][2] = {\n";
+  for (unsigned I = 0, E = RegBank.getNumNativeRegUnits(); I != E; ++I) {
+    ArrayRef<const CodeGenRegister *> const Roots =
+        RegBank.getRegUnit(I).getRoots();
+    assert(!Roots.empty() && "All regunits must have a root register.");
+    assert(Roots.size() <= 2 && "More than two roots not supported yet.");
+    OS << "  { ";
+    ListSeparator LS;
+    for (const CodeGenRegister *R : Roots)
+      OS << LS << getQualifiedName(R->TheDef);
+    OS << " },\n";
+  }
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitRegClasses(
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    SequenceToOffsetTable<std::string> &RegClassStrings,
+    CodeGenTarget const &Target) const {
+  for (const auto &RC : RegClasses) {
+    ArrayRef<Record *> const Order = RC.getOrder();
+
+    // Give the register class a legal C name if it's anonymous.
+    const std::string &Name = RC.getName();
+
+    RegClassStrings.add(Name);
+
+    // Emit the register list now (unless it would be a zero-length array).
+    if (!Order.empty()) {
+      OS << "  // " << Name << " Register Class...\n"
+         << "  const MCPhysReg " << Name << "[] = {\n    ";
+      for (Record *Reg : Order) {
+        OS << getQualifiedName(Reg) << ", ";
+      }
+      OS << "\n  };\n\n";
+
+      OS << "  // " << Name << " Bit set.\n"
+         << "  const uint8_t " << Name << "Bits[] = {\n    ";
+      PrinterBitVectorEmitter BVE;
+      for (Record *Reg : Order) {
+        BVE.add(Target.getRegBank().getReg(Reg)->EnumValue);
+      }
+      BVE.print(OS);
+      OS << "\n  };\n\n";
+    }
+  }
+}
+
+void PrinterLLVM::regInfoEmitStrLiteralRegClasses(
+    std::string const TargetName,
+    SequenceToOffsetTable<std::string> const &RegClassStrings) const {
+  RegClassStrings.emitStringLiteralDef(
+      OS, Twine("extern const char ") + TargetName + "RegClassStrings[]");
+}
+
+void PrinterLLVM::regInfoEmitMCRegClassesTable(
+    std::string const TargetName,
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    SequenceToOffsetTable<std::string> &RegClassStrings) const {
+  OS << "extern const MCRegisterClass " << TargetName
+     << "MCRegisterClasses[] = {\n";
+
+  for (const auto &RC : RegClasses) {
+    ArrayRef<Record *> const Order = RC.getOrder();
+    std::string const RCName = Order.empty() ? "nullptr" : RC.getName();
+    std::string const RCBitsName =
+        Order.empty() ? "nullptr" : RC.getName() + "Bits";
+    std::string const RCBitsSize =
+        Order.empty() ? "0" : "sizeof(" + RCBitsName + ")";
+    assert(isInt<8>(RC.CopyCost) && "Copy cost too large.");
+    uint32_t RegSize = 0;
+    if (RC.RSI.isSimple())
+      RegSize = RC.RSI.getSimple().RegSize;
+    OS << "  { " << RCName << ", " << RCBitsName << ", "
+       << RegClassStrings.get(RC.getName()) << ", " << RC.getOrder().size()
+       << ", " << RCBitsSize << ", " << RC.getQualifiedName() + "RegClassID"
+       << ", " << RegSize << ", " << RC.CopyCost << ", "
+       << (RC.Allocatable ? "true" : "false") << " },\n";
+  }
+
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitRegEncodingTable(
+    std::string const TargetName,
+    std::deque<CodeGenRegister> const &Regs) const {
+  OS << "extern const uint16_t " << TargetName;
+  OS << "RegEncodingTable[] = {\n";
+  // Add entry for NoRegister
+  OS << "  0,\n";
+  for (const auto &RE : Regs) {
+    Record *Reg = RE.TheDef;
+    BitsInit *BI = Reg->getValueAsBitsInit("HWEncoding");
+    uint64_t Value = 0;
+    for (unsigned I = 0, Ie = BI->getNumBits(); I != Ie; ++I) {
+      if (BitInit *B = dyn_cast<BitInit>(BI->getBit(I)))
+        Value |= (uint64_t)B->getValue() << I;
+    }
+    OS << "  " << Value << ",\n";
+  }
+  OS << "};\n"; // End of HW encoding table
+}
+
+void PrinterLLVM::regInfoEmitMCRegInfoInit(
+    std::string const TargetName, CodeGenRegBank const &RegBank,
+    std::deque<CodeGenRegister> const &Regs,
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices) const {
+  OS << "static inline void Init" << TargetName
+     << "MCRegisterInfo(MCRegisterInfo *RI, unsigned RA, "
+     << "unsigned DwarfFlavour = 0, unsigned EHFlavour = 0, unsigned PC = 0) "
+        "{\n"
+     << "  RI->InitMCRegisterInfo(" << TargetName << "RegDesc, "
+     << Regs.size() + 1 << ", RA, PC, " << TargetName << "MCRegisterClasses, "
+     << RegClasses.size() << ", " << TargetName << "RegUnitRoots, "
+     << RegBank.getNumNativeRegUnits() << ", " << TargetName << "RegDiffLists, "
+     << TargetName << "LaneMaskLists, " << TargetName << "RegStrings, "
+     << TargetName << "RegClassStrings, " << TargetName << "SubRegIdxLists, "
+     << (std::distance(SubRegIndices.begin(), SubRegIndices.end()) + 1) << ",\n"
+     << TargetName << "SubRegIdxRanges, " << TargetName
+     << "RegEncodingTable);\n\n";
+}
+
+void PrinterLLVM::regInfoEmitInfoDwarfRegsRev(StringRef const &Namespace,
+                                              DwarfRegNumsVecTy &DwarfRegNums,
+                                              unsigned MaxLength,
+                                              bool IsCtor) const {
+  OS << "// " << Namespace << " Dwarf<->LLVM register mappings.\n";
+
+  // Emit reverse information about the dwarf register numbers.
+  for (unsigned j = 0; j < 2; ++j) {
+    for (unsigned I = 0, E = MaxLength; I != E; ++I) {
+      OS << "extern const MCRegisterInfo::DwarfLLVMRegPair " << Namespace;
+      OS << (j == 0 ? "DwarfFlavour" : "EHFlavour");
+      OS << I << "Dwarf2L[]";
+
+      if (!IsCtor) {
+        OS << " = {\n";
+
+        // Store the mapping sorted by the LLVM reg num so lookup can be done
+        // with a binary search.
+        std::map<uint64_t, Record *> Dwarf2LMap;
+        for (auto &DwarfRegNum : DwarfRegNums) {
+          int DwarfRegNo = DwarfRegNum.second[I];
+          if (DwarfRegNo < 0)
+            continue;
+          Dwarf2LMap[DwarfRegNo] = DwarfRegNum.first;
+        }
+
+        for (auto &I : Dwarf2LMap)
+          OS << "  { " << I.first << "U, " << getQualifiedName(I.second)
+             << " },\n";
+
+        OS << "};\n";
+      } else {
+        OS << ";\n";
+      }
+
+      // We have to store the size in a const global, it's used in multiple
+      // places.
+      OS << "extern const unsigned " << Namespace
+         << (j == 0 ? "DwarfFlavour" : "EHFlavour") << I << "Dwarf2LSize";
+      if (!IsCtor)
+        OS << " = std::size(" << Namespace
+           << (j == 0 ? "DwarfFlavour" : "EHFlavour") << I << "Dwarf2L);\n\n";
+      else
+        OS << ";\n\n";
+    }
+  }
+}
+
+void PrinterLLVM::regInfoEmitInfoDwarfRegs(StringRef const &Namespace,
+                                           DwarfRegNumsVecTy &DwarfRegNums,
+                                           unsigned MaxLength,
+                                           bool IsCtor) const {
+  for (unsigned J = 0; J < 2; ++J) {
+    for (unsigned I = 0, E = MaxLength; I != E; ++I) {
+      OS << "extern const MCRegisterInfo::DwarfLLVMRegPair " << Namespace;
+      OS << (J == 0 ? "DwarfFlavour" : "EHFlavour");
+      OS << I << "L2Dwarf[]";
+      if (!IsCtor) {
+        OS << " = {\n";
+        // Store the mapping sorted by the Dwarf reg num so lookup can be done
+        // with a binary search.
+        for (auto &DwarfRegNum : DwarfRegNums) {
+          int RegNo = DwarfRegNum.second[I];
+          if (RegNo == -1) // -1 is the default value, don't emit a mapping.
+            continue;
+
+          OS << "  { " << getQualifiedName(DwarfRegNum.first) << ", " << RegNo
+             << "U },\n";
+        }
+        OS << "};\n";
+      } else {
+        OS << ";\n";
+      }
+
+      // We have to store the size in a const global, it's used in multiple
+      // places.
+      OS << "extern const unsigned " << Namespace
+         << (J == 0 ? "DwarfFlavour" : "EHFlavour") << I << "L2DwarfSize";
+      if (!IsCtor)
+        OS << " = std::size(" << Namespace
+           << (J == 0 ? "DwarfFlavour" : "EHFlavour") << I << "L2Dwarf);\n\n";
+      else
+        OS << ";\n\n";
+    }
+  }
+}
+
+void PrinterLLVM::regInfoEmitInfoRegMapping(StringRef const &Namespace,
+                                            unsigned MaxLength,
+                                            bool IsCtor) const {
+  if (MaxLength == 0) {
+    OS << "}\n\n";
+    return;
+  }
+
+  // Emit reverse information about the dwarf register numbers.
+  for (unsigned J = 0; J < 2; ++J) {
+    OS << "  switch (";
+    if (J == 0)
+      OS << "DwarfFlavour";
+    else
+      OS << "EHFlavour";
+    OS << ") {\n"
+       << "  default:\n"
+       << "    llvm_unreachable(\"Unknown DWARF flavour\");\n";
+
+    for (unsigned I = 0, E = MaxLength; I != E; ++I) {
+      OS << "  case " << I << ":\n";
+      OS << "    ";
+      if (!IsCtor)
+        OS << "RI->";
+      std::string Tmp;
+      raw_string_ostream(Tmp)
+          << Namespace << (J == 0 ? "DwarfFlavour" : "EHFlavour") << I
+          << "Dwarf2L";
+      OS << "mapDwarfRegsToLLVMRegs(" << Tmp << ", " << Tmp << "Size, ";
+      if (J == 0)
+        OS << "false";
+      else
+        OS << "true";
+      OS << ");\n";
+      OS << "    break;\n";
+    }
+    OS << "  }\n";
+  }
+
+  // Emit information about the dwarf register numbers.
+  for (unsigned J = 0; J < 2; ++J) {
+    OS << "  switch (";
+    if (J == 0)
+      OS << "DwarfFlavour";
+    else
+      OS << "EHFlavour";
+    OS << ") {\n"
+       << "  default:\n"
+       << "    llvm_unreachable(\"Unknown DWARF flavour\");\n";
+
+    for (unsigned I = 0, E = MaxLength; I != E; ++I) {
+      OS << "  case " << I << ":\n";
+      OS << "    ";
+      if (!IsCtor)
+        OS << "RI->";
+      std::string Tmp;
+      raw_string_ostream(Tmp)
+          << Namespace << (J == 0 ? "DwarfFlavour" : "EHFlavour") << I
+          << "L2Dwarf";
+      OS << "mapLLVMRegsToDwarfRegs(" << Tmp << ", " << Tmp << "Size, ";
+      if (J == 0)
+        OS << "false";
+      else
+        OS << "true";
+      OS << ");\n";
+      OS << "    break;\n";
+    }
+    OS << "  }\n";
+  }
+
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitHeaderIncludes() const {
+  OS << "#include \"llvm/CodeGen/TargetRegisterInfo.h\"\n\n";
+}
+
+void PrinterLLVM::regInfoEmitHeaderExternRegClasses(
+    std::list<CodeGenRegisterClass> const &RegClasses) const {
+  for (const auto &RC : RegClasses) {
+    const std::string &Name = RC.getName();
+
+    // Output the extern for the instance.
+    OS << "  extern const TargetRegisterClass " << Name << "RegClass;\n";
+  }
+}
+
+void PrinterLLVM::regInfoEmitHeaderDecl(std::string const &TargetName,
+                                        std::string const &ClassName,
+                                        bool SubRegsPresent,
+                                        bool DeclareGetPhysRegBaseClass) const {
+  OS << "class " << TargetName << "FrameLowering;\n\n";
+
+  OS << "struct " << ClassName << " : public TargetRegisterInfo {\n"
+     << "  explicit " << ClassName
+     << "(unsigned RA, unsigned D = 0, unsigned E = 0,\n"
+     << "      unsigned PC = 0, unsigned HwMode = 0);\n";
+  if (SubRegsPresent) {
+    OS << "  unsigned composeSubRegIndicesImpl"
+       << "(unsigned, unsigned) const override;\n"
+       << "  LaneBitmask composeSubRegIndexLaneMaskImpl"
+       << "(unsigned, LaneBitmask) const override;\n"
+       << "  LaneBitmask reverseComposeSubRegIndexLaneMaskImpl"
+       << "(unsigned, LaneBitmask) const override;\n"
+       << "  const TargetRegisterClass *getSubClassWithSubReg"
+       << "(const TargetRegisterClass *, unsigned) const override;\n"
+       << "  const TargetRegisterClass *getSubRegisterClass"
+       << "(const TargetRegisterClass *, unsigned) const override;\n";
+  }
+  OS << "  const RegClassWeight &getRegClassWeight("
+     << "const TargetRegisterClass *RC) const override;\n"
+     << "  unsigned getRegUnitWeight(unsigned RegUnit) const override;\n"
+     << "  unsigned getNumRegPressureSets() const override;\n"
+     << "  const char *getRegPressureSetName(unsigned Idx) const override;\n"
+     << "  unsigned getRegPressureSetLimit(const MachineFunction &MF, unsigned "
+        "Idx) const override;\n"
+     << "  const int *getRegClassPressureSets("
+     << "const TargetRegisterClass *RC) const override;\n"
+     << "  const int *getRegUnitPressureSets("
+     << "unsigned RegUnit) const override;\n"
+     << "  ArrayRef<const char *> getRegMaskNames() const override;\n"
+     << "  ArrayRef<const uint32_t *> getRegMasks() const override;\n"
+     << "  bool isGeneralPurposeRegister(const MachineFunction &, "
+     << "MCRegister) const override;\n"
+     << "  bool isFixedRegister(const MachineFunction &, "
+     << "MCRegister) const override;\n"
+     << "  bool isArgumentRegister(const MachineFunction &, "
+     << "MCRegister) const override;\n"
+     << "  bool isConstantPhysReg(MCRegister PhysReg) const override final;\n"
+     << "  /// Devirtualized TargetFrameLowering.\n"
+     << "  static const " << TargetName << "FrameLowering *getFrameLowering(\n"
+     << "      const MachineFunction &MF);\n";
+  if (DeclareGetPhysRegBaseClass) {
+    OS << "  const TargetRegisterClass *getPhysRegBaseClass(MCRegister Reg) "
+          "const override;\n";
+  }
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitExternRegClassesArr(
+    std::string const &TargetName) const {
+  OS << "extern const MCRegisterClass " << TargetName
+     << "MCRegisterClasses[];\n";
+}
+
+static void printSimpleValueType(raw_ostream &OS, MVT::SimpleValueType VT) {
+  OS << getEnumName(VT);
+}
+
+void PrinterLLVM::regInfoEmitVTSeqs(
+    SequenceToOffsetTable<std::vector<MVT::SimpleValueType>> const &VTSeqs)
+    const {
+  OS << "\nstatic const MVT::SimpleValueType VTLists[] = {\n";
+  VTSeqs.emit(OS, printSimpleValueType, "MVT::Other");
+  OS << "};\n";
+}
+
+static void printMask(raw_ostream &OS, LaneBitmask Val) {
+  OS << "LaneBitmask(0x" << PrintLaneMask(Val) << ')';
+}
+
+void PrinterLLVM::regInfoEmitSubRegIdxTable(
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices) const {
+  OS << "\nstatic const char *SubRegIndexNameTable[] = { \"";
+
+  for (const auto &Idx : SubRegIndices) {
+    OS << Idx.getName();
+    OS << "\", \"";
+  }
+  OS << "\" };\n\n";
+
+  // Emit SubRegIndex lane masks, including 0.
+  OS << "\nstatic const LaneBitmask SubRegIndexLaneMaskTable[] = {\n  "
+        "LaneBitmask::getAll(),\n";
+  for (const auto &Idx : SubRegIndices) {
+    printMask(OS << "  ", Idx.LaneMask);
+    OS << ", // " << Idx.getName() << '\n';
+  }
+  OS << " };\n\n";
+
+  OS << "\n";
+}
+
+void PrinterLLVM::regInfoEmitRegClassInfoTable(
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    SequenceToOffsetTable<std::vector<MVT::SimpleValueType>> const &VTSeqs,
+    CodeGenHwModes const &CGH, unsigned NumModes) const {
+  OS << "\nstatic const TargetRegisterInfo::RegClassInfo RegClassInfos[]"
+     << " = {\n";
+  for (unsigned M = 0; M < NumModes; ++M) {
+    unsigned EV = 0;
+    OS << "  // Mode = " << M << " (";
+    if (M == 0)
+      OS << "Default";
+    else
+      OS << CGH.getMode(M).Name;
+    OS << ")\n";
+    for (const auto &RC : RegClasses) {
+      assert(RC.EnumValue == EV && "Unexpected order of register classes");
+      ++EV;
+      (void)EV;
+      const RegSizeInfo &RI = RC.RSI.get(M);
+      OS << "  { " << RI.RegSize << ", " << RI.SpillSize << ", "
+         << RI.SpillAlignment;
+      std::vector<MVT::SimpleValueType> VTs;
+      for (const ValueTypeByHwMode &VVT : RC.VTs)
+        VTs.push_back(VVT.get(M).SimpleTy);
+      OS << ", VTLists+" << VTSeqs.get(VTs) << " },    // " << RC.getName()
+         << '\n';
+    }
+  }
+  OS << "};\n";
+
+  OS << "\nstatic const TargetRegisterClass *const "
+     << "NullRegClasses[] = { nullptr };\n\n";
+}
+
+void PrinterLLVM::regInfoEmitSubClassMaskTable(
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    SmallVector<IdxList, 8> &SuperRegIdxLists,
+    SequenceToOffsetTable<IdxList, deref<std::less<>>> &SuperRegIdxSeqs,
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices,
+    BitVector &MaskBV) const {
+  for (const auto &RC : RegClasses) {
+    OS << "static const uint32_t " << RC.getName() << "SubClassMask[] = {\n  ";
+    printBitVectorAsHex(OS, RC.getSubClasses(), 32);
+
+    // Emit super-reg class masks for any relevant SubRegIndices that can
+    // project into RC.
+    IdxList &SRIList = SuperRegIdxLists[RC.EnumValue];
+    for (auto &Idx : SubRegIndices) {
+      MaskBV.reset();
+      RC.getSuperRegClasses(&Idx, MaskBV);
+      if (MaskBV.none())
+        continue;
+      SRIList.push_back(&Idx);
+      OS << "\n  ";
+      printBitVectorAsHex(OS, MaskBV, 32);
+      OS << "// " << Idx.getName();
+    }
+    SuperRegIdxSeqs.add(SRIList);
+    OS << "\n};\n\n";
+  }
+}
+
+static void printSubRegIndex(raw_ostream &OS, const CodeGenSubRegIndex *Idx) {
+  OS << Idx->EnumValue;
+}
+
+void PrinterLLVM::regInfoEmitSuperRegIdxSeqsTable(
+    SequenceToOffsetTable<IdxList, deref<std::less<>>> const &SuperRegIdxSeqs)
+    const {
+  OS << "static const uint16_t SuperRegIdxSeqs[] = {\n";
+  SuperRegIdxSeqs.emit(OS, printSubRegIndex);
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitSuperClassesTable(
+    std::list<CodeGenRegisterClass> const &RegClasses) const {
+  for (const auto &RC : RegClasses) {
+    ArrayRef<CodeGenRegisterClass *> const Supers = RC.getSuperClasses();
+
+    // Skip classes without supers.  We can reuse NullRegClasses.
+    if (Supers.empty())
+      continue;
+
+    OS << "static const TargetRegisterClass *const " << RC.getName()
+       << "Superclasses[] = {\n";
+    for (const auto *Super : Supers)
+      OS << "  &" << Super->getQualifiedName() << "RegClass,\n";
+    OS << "  nullptr\n};\n\n";
+  }
+}
+
+void PrinterLLVM::regInfoEmitRegClassMethods(
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    std::string const &TargetName) const {
+  for (const auto &RC : RegClasses) {
+    if (!RC.AltOrderSelect.empty()) {
+      OS << "\nstatic inline unsigned " << RC.getName()
+         << "AltOrderSelect(const MachineFunction &MF) {" << RC.AltOrderSelect
+         << "}\n\n"
+         << "static ArrayRef<MCPhysReg> " << RC.getName()
+         << "GetRawAllocationOrder(const MachineFunction &MF) {\n";
+      for (unsigned Oi = 1, Oe = RC.getNumOrders(); Oi != Oe; ++Oi) {
+        ArrayRef<Record *> const Elems = RC.getOrder(Oi);
+        if (!Elems.empty()) {
+          OS << "  static const MCPhysReg AltOrder" << Oi << "[] = {";
+          for (unsigned Elem = 0; Elem != Elems.size(); ++Elem)
+            OS << (Elem ? ", " : " ") << getQualifiedName(Elems[Elem]);
+          OS << " };\n";
+        }
+      }
+      OS << "  const MCRegisterClass &MCR = " << TargetName
+         << "MCRegisterClasses[" << RC.getQualifiedName() + "RegClassID];\n"
+         << "  const ArrayRef<MCPhysReg> Order[] = {\n"
+         << "    makeArrayRef(MCR.begin(), MCR.getNumRegs()";
+      for (unsigned Oi = 1, Oe = RC.getNumOrders(); Oi != Oe; ++Oi)
+        if (RC.getOrder(Oi).empty())
+          OS << "),\n    ArrayRef<MCPhysReg>(";
+        else
+          OS << "),\n    makeArrayRef(AltOrder" << Oi;
+      OS << ")\n  };\n  const unsigned Select = " << RC.getName()
+         << "AltOrderSelect(MF);\n  assert(Select < " << RC.getNumOrders()
+         << ");\n  return Order[Select];\n}\n";
+    }
+  }
+}
+
+void PrinterLLVM::regInfomitRegClassInstances(
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    SequenceToOffsetTable<IdxList, deref<std::less<>>> const &SuperRegIdxSeqs,
+    SmallVector<IdxList, 8> const &SuperRegIdxLists,
+    std::string const &TargetName) const {
+  for (const auto &RC : RegClasses) {
+    OS << "  extern const TargetRegisterClass " << RC.getName()
+       << "RegClass = {\n    " << '&' << TargetName << "MCRegisterClasses["
+       << RC.getName() << "RegClassID],\n    " << RC.getName()
+       << "SubClassMask,\n    SuperRegIdxSeqs + "
+       << SuperRegIdxSeqs.get(SuperRegIdxLists[RC.EnumValue]) << ",\n    ";
+    printMask(OS, RC.LaneMask);
+    OS << ",\n    " << (unsigned)RC.AllocationPriority << ",\n    "
+       << (RC.GlobalPriority ? "true" : "false") << ",\n    "
+       << format("0x%02x", RC.TSFlags) << ", /* TSFlags */\n    "
+       << (RC.HasDisjunctSubRegs ? "true" : "false")
+       << ", /* HasDisjunctSubRegs */\n    "
+       << (RC.CoveredBySubRegs ? "true" : "false")
+       << ", /* CoveredBySubRegs */\n    ";
+    if (RC.getSuperClasses().empty())
+      OS << "NullRegClasses,\n    ";
+    else
+      OS << RC.getName() << "Superclasses,\n    ";
+    if (RC.AltOrderSelect.empty())
+      OS << "nullptr\n";
+    else
+      OS << RC.getName() << "GetRawAllocationOrder\n";
+    OS << "  };\n\n";
+  }
+}
+
+void PrinterLLVM::regInfoEmitRegClassTable(
+    std::list<CodeGenRegisterClass> const &RegClasses) const {
+  OS << "  const TargetRegisterClass *const RegisterClasses[] = {\n";
+  for (const auto &RC : RegClasses)
+    OS << "    &" << RC.getQualifiedName() << "RegClass,\n";
+  OS << "  };\n";
+}
+
+void PrinterLLVM::regInfoEmitCostPerUseTable(
+    std::vector<unsigned> const &AllRegCostPerUse, unsigned NumRegCosts) const {
+  OS << "\nstatic const uint8_t "
+     << "CostPerUseTable[] = { \n";
+  for (unsigned int I = 0; I < NumRegCosts; ++I) {
+    for (unsigned J = I, E = AllRegCostPerUse.size(); J < E; J += NumRegCosts)
+      OS << AllRegCostPerUse[J] << ", ";
+  }
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitInAllocatableClassTable(
+    llvm::BitVector const &InAllocClass) const {
+  OS << "\nstatic const bool "
+     << "InAllocatableClassTable[] = { \n";
+  for (unsigned I = 0, E = InAllocClass.size(); I < E; ++I) {
+    OS << (InAllocClass[I] ? "true" : "false") << ", ";
+  }
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitRegExtraDesc(std::string const &TargetName,
+                                          unsigned NumRegCosts) const {
+  OS << "\nstatic const TargetRegisterInfoDesc " << TargetName
+     << "RegInfoDesc = { // Extra Descriptors\n";
+  OS << "CostPerUseTable, " << NumRegCosts << ", "
+     << "InAllocatableClassTable";
+  OS << "};\n\n";
+}
+
+void PrinterLLVM::regInfoEmitSubClassSubRegGetter(
+    std::string const &ClassName, unsigned SubRegIndicesSize,
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices,
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    CodeGenRegBank &RegBank) const {
+  // Emit getSubClassWithSubReg.
+  OS << "const TargetRegisterClass *" << ClassName
+     << "::getSubClassWithSubReg(const TargetRegisterClass *RC, unsigned Idx)"
+     << " const {\n";
+  // Use the smallest type that can hold a regclass ID with room for a
+  // sentinel.
+  if (RegClasses.size() <= UINT8_MAX)
+    OS << "  static const uint8_t Table[";
+  else if (RegClasses.size() <= UINT16_MAX)
+    OS << "  static const uint16_t Table[";
+  else
+    PrintFatalError("Too many register classes.");
+  OS << RegClasses.size() << "][" << SubRegIndicesSize << "] = {\n";
+  for (const auto &RC : RegClasses) {
+    OS << "    {\t// " << RC.getName() << "\n";
+    for (auto &Idx : SubRegIndices) {
+      if (CodeGenRegisterClass *SRC = RC.getSubClassWithSubReg(&Idx))
+        OS << "      " << SRC->EnumValue + 1 << ",\t// " << Idx.getName()
+           << " -> " << SRC->getName() << "\n";
+      else
+        OS << "      0,\t// " << Idx.getName() << "\n";
+    }
+    OS << "    },\n";
+  }
+  OS << "  };\n  assert(RC && \"Missing regclass\");\n"
+     << "  if (!Idx) return RC;\n  --Idx;\n"
+     << "  assert(Idx < " << SubRegIndicesSize << " && \"Bad subreg\");\n"
+     << "  unsigned TV = Table[RC->getID()][Idx];\n"
+     << "  return TV ? getRegClass(TV - 1) : nullptr;\n}\n\n";
+
+  // Emit getSubRegisterClass
+  OS << "const TargetRegisterClass *" << ClassName
+     << "::getSubRegisterClass(const TargetRegisterClass *RC, unsigned Idx)"
+     << " const {\n";
+
+  // Use the smallest type that can hold a regclass ID with room for a
+  // sentinel.
+  if (RegClasses.size() <= UINT8_MAX)
+    OS << "  static const uint8_t Table[";
+  else if (RegClasses.size() <= UINT16_MAX)
+    OS << "  static const uint16_t Table[";
+  else
+    PrintFatalError("Too many register classes.");
+
+  OS << RegClasses.size() << "][" << SubRegIndicesSize << "] = {\n";
+
+  for (const auto &RC : RegClasses) {
+    OS << "    {\t// " << RC.getName() << '\n';
+    for (auto &Idx : SubRegIndices) {
+      std::optional<std::pair<CodeGenRegisterClass *, CodeGenRegisterClass *>>
+          MatchingSubClass = RC.getMatchingSubClassWithSubRegs(RegBank, &Idx);
+
+      unsigned EnumValue = 0;
+      if (MatchingSubClass) {
+        CodeGenRegisterClass *SubRegClass = MatchingSubClass->second;
+        EnumValue = SubRegClass->EnumValue + 1;
+      }
+
+      OS << "      " << EnumValue << ",\t// " << RC.getName() << ':'
+         << Idx.getName();
+
+      if (MatchingSubClass) {
+        CodeGenRegisterClass *SubRegClass = MatchingSubClass->second;
+        OS << " -> " << SubRegClass->getName();
+      }
+
+      OS << '\n';
+    }
+
+    OS << "    },\n";
+  }
+  OS << "  };\n  assert(RC && \"Missing regclass\");\n"
+     << "  if (!Idx) return RC;\n  --Idx;\n"
+     << "  assert(Idx < " << SubRegIndicesSize << " && \"Bad subreg\");\n"
+     << "  unsigned TV = Table[RC->getID()][Idx];\n"
+     << "  return TV ? getRegClass(TV - 1) : nullptr;\n}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitRegClassWeight(
+    CodeGenRegBank const &RegBank, std::string const &ClassName) const {
+  OS << "/// Get the weight in units of pressure for this register class.\n"
+     << "const RegClassWeight &" << ClassName << "::\n"
+     << "getRegClassWeight(const TargetRegisterClass *RC) const {\n"
+     << "  static const RegClassWeight RCWeightTable[] = {\n";
+  for (const auto &RC : RegBank.getRegClasses()) {
+    const CodeGenRegister::Vec &Regs = RC.getMembers();
+    OS << "    {" << RC.getWeight(RegBank) << ", ";
+    if (Regs.empty() || RC.Artificial)
+      OS << '0';
+    else {
+      std::vector<unsigned> RegUnits;
+      RC.buildRegUnitSet(RegBank, RegUnits);
+      OS << RegBank.getRegUnitSetWeight(RegUnits);
+    }
+    OS << "},  \t// " << RC.getName() << "\n";
+  }
+  OS << "  };\n"
+     << "  return RCWeightTable[RC->getID()];\n"
+     << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitRegUnitWeight(CodeGenRegBank const &RegBank,
+                                           std::string const &ClassName,
+                                           bool RegUnitsHaveUnitWeight) const {
+  OS << "/// Get the weight in units of pressure for this register unit.\n"
+     << "unsigned " << ClassName << "::\n"
+     << "getRegUnitWeight(unsigned RegUnit) const {\n"
+     << "  assert(RegUnit < " << RegBank.getNumNativeRegUnits()
+     << " && \"invalid register unit\");\n";
+  if (!RegUnitsHaveUnitWeight) {
+    OS << "  static const uint8_t RUWeightTable[] = {\n    ";
+    for (unsigned UnitIdx = 0, UnitEnd = RegBank.getNumNativeRegUnits();
+         UnitIdx < UnitEnd; ++UnitIdx) {
+      const RegUnit &RU = RegBank.getRegUnit(UnitIdx);
+      assert(RU.Weight < 256 && "RegUnit too heavy");
+      OS << RU.Weight << ", ";
+    }
+    OS << "};\n"
+       << "  return RUWeightTable[RegUnit];\n";
+  } else {
+    OS << "  // All register units have unit weight.\n"
+       << "  return 1;\n";
+  }
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitGetNumRegPressureSets(std::string const &ClassName,
+                                                   unsigned NumSets) const {
+  OS << "\n"
+     << "// Get the number of dimensions of register pressure.\n"
+     << "unsigned " << ClassName << "::getNumRegPressureSets() const {\n"
+     << "  return " << NumSets << ";\n}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitGetRegPressureTables(CodeGenRegBank const &RegBank,
+                                                  std::string const &ClassName,
+                                                  unsigned NumSets) const {
+  OS << "// Get the name of this register unit pressure set.\n"
+     << "const char *" << ClassName << "::\n"
+     << "getRegPressureSetName(unsigned Idx) const {\n"
+     << "  static const char *PressureNameTable[] = {\n";
+  unsigned MaxRegUnitWeight = 0;
+  for (unsigned I = 0; I < NumSets; ++I) {
+    const RegUnitSet &RegUnits = RegBank.getRegSetAt(I);
+    MaxRegUnitWeight = std::max(MaxRegUnitWeight, RegUnits.Weight);
+    OS << "    \"" << RegUnits.Name << "\",\n";
+  }
+  OS << "  };\n"
+     << "  return PressureNameTable[Idx];\n"
+     << "}\n\n";
+
+  OS << "// Get the register unit pressure limit for this dimension.\n"
+     << "// This limit must be adjusted dynamically for reserved registers.\n"
+     << "unsigned " << ClassName << "::\n"
+     << "getRegPressureSetLimit(const MachineFunction &MF, unsigned Idx) const "
+        "{\n"
+     << "  static const " << getMinimalTypeForRange(MaxRegUnitWeight, 32)
+     << " PressureLimitTable[] = {\n";
+  for (unsigned I = 0; I < NumSets; ++I) {
+    const RegUnitSet &RegUnits = RegBank.getRegSetAt(I);
+    OS << "    " << RegUnits.Weight << ",  \t// " << I << ": " << RegUnits.Name
+       << "\n";
+  }
+  OS << "  };\n"
+     << "  return PressureLimitTable[Idx];\n"
+     << "}\n\n";
+}
+
+static void printInt(raw_ostream &OS, int Val) { OS << Val; }
+
+void PrinterLLVM::regInfoEmitRCSetsTable(
+    std::string const &ClassName, unsigned NumRCs,
+    SequenceToOffsetTable<std::vector<int>> const &PSetsSeqs,
+    std::vector<std::vector<int>> const &PSets) const {
+  OS << "/// Table of pressure sets per register class or unit.\n"
+     << "static const int RCSetsTable[] = {\n";
+  PSetsSeqs.emit(OS, printInt, "-1");
+  OS << "};\n\n";
+
+  OS << "/// Get the dimensions of register pressure impacted by this "
+     << "register class.\n"
+     << "/// Returns a -1 terminated array of pressure set IDs\n"
+     << "const int *" << ClassName << "::\n"
+     << "getRegClassPressureSets(const TargetRegisterClass *RC) const {\n";
+  OS << "  static const " << getMinimalTypeForRange(PSetsSeqs.size() - 1, 32)
+     << " RCSetStartTable[] = {\n    ";
+  for (unsigned I = 0, E = NumRCs; I != E; ++I) {
+    OS << PSetsSeqs.get(PSets[I]) << ",";
+  }
+  OS << "};\n"
+     << "  return &RCSetsTable[RCSetStartTable[RC->getID()]];\n"
+     << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitGetRegUnitPressureSets(
+    SequenceToOffsetTable<std::vector<int>> const &PSetsSeqs,
+    CodeGenRegBank const &RegBank, std::string const &ClassName,
+    std::vector<std::vector<int>> const &PSets) const {
+  OS << "/// Get the dimensions of register pressure impacted by this "
+     << "register unit.\n"
+     << "/// Returns a -1 terminated array of pressure set IDs\n"
+     << "const int *" << ClassName << "::\n"
+     << "getRegUnitPressureSets(unsigned RegUnit) const {\n"
+     << "  assert(RegUnit < " << RegBank.getNumNativeRegUnits()
+     << " && \"invalid register unit\");\n";
+  OS << "  static const " << getMinimalTypeForRange(PSetsSeqs.size() - 1, 32)
+     << " RUSetStartTable[] = {\n    ";
+  for (unsigned UnitIdx = 0, UnitEnd = RegBank.getNumNativeRegUnits();
+       UnitIdx < UnitEnd; ++UnitIdx) {
+    OS << PSetsSeqs.get(PSets[RegBank.getRegUnit(UnitIdx).RegClassUnitSetsIdx])
+       << ",";
+  }
+  OS << "};\n"
+     << "  return &RCSetsTable[RUSetStartTable[RegUnit]];\n"
+     << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitExternTableDecl(
+    std::string const &TargetName) const {
+  OS << "extern const MCRegisterDesc " << TargetName << "RegDesc[];\n";
+  OS << "extern const MCPhysReg " << TargetName << "RegDiffLists[];\n";
+  OS << "extern const LaneBitmask " << TargetName << "LaneMaskLists[];\n";
+  OS << "extern const char " << TargetName << "RegStrings[];\n";
+  OS << "extern const char " << TargetName << "RegClassStrings[];\n";
+  OS << "extern const MCPhysReg " << TargetName << "RegUnitRoots[][2];\n";
+  OS << "extern const uint16_t " << TargetName << "SubRegIdxLists[];\n";
+  OS << "extern const MCRegisterInfo::SubRegCoveredBits " << TargetName
+     << "SubRegIdxRanges[];\n";
+  OS << "extern const uint16_t " << TargetName << "RegEncodingTable[];\n";
+}
+
+void PrinterLLVM::regInfoEmitRegClassInit(
+    std::string const &TargetName, std::string const &ClassName,
+    CodeGenRegBank const &RegBank,
+    std::list<CodeGenRegisterClass> const &RegClasses,
+    std::deque<CodeGenRegister> const &Regs, unsigned SubRegIndicesSize) const {
+  OS << ClassName << "::\n"
+     << ClassName
+     << "(unsigned RA, unsigned DwarfFlavour, unsigned EHFlavour,\n"
+        "      unsigned PC, unsigned HwMode)\n"
+     << "  : TargetRegisterInfo(&" << TargetName << "RegInfoDesc"
+     << ", RegisterClasses, RegisterClasses+" << RegClasses.size() << ",\n"
+     << "             SubRegIndexNameTable, SubRegIndexLaneMaskTable,\n"
+     << "             ";
+  printMask(OS, RegBank.CoveringLanes);
+  OS << ", RegClassInfos, HwMode) {\n"
+     << "  InitMCRegisterInfo(" << TargetName << "RegDesc, " << Regs.size() + 1
+     << ", RA, PC,\n                     " << TargetName
+     << "MCRegisterClasses, " << RegClasses.size() << ",\n"
+     << "                     " << TargetName << "RegUnitRoots,\n"
+     << "                     " << RegBank.getNumNativeRegUnits() << ",\n"
+     << "                     " << TargetName << "RegDiffLists,\n"
+     << "                     " << TargetName << "LaneMaskLists,\n"
+     << "                     " << TargetName << "RegStrings,\n"
+     << "                     " << TargetName << "RegClassStrings,\n"
+     << "                     " << TargetName << "SubRegIdxLists,\n"
+     << "                     " << SubRegIndicesSize + 1 << ",\n"
+     << "                     " << TargetName << "SubRegIdxRanges,\n"
+     << "                     " << TargetName << "RegEncodingTable);\n\n";
+}
+
+void PrinterLLVM::regInfoEmitSaveListTable(
+    Record const *CSRSet, SetTheory::RecVec const *Regs) const {
+  OS << "static const MCPhysReg " << CSRSet->getName() << "_SaveList[] = { ";
+  for (unsigned R = 0, Re = Regs->size(); R != Re; ++R)
+    OS << getQualifiedName((*Regs)[R]) << ", ";
+  OS << "0 };\n";
+}
+
+void PrinterLLVM::regInfoEmitRegMaskTable(std::string const &CSRSetName,
+                                          BitVector &Covered) const {
+  OS << "static const uint32_t " << CSRSetName << "_RegMask[] = { ";
+  printBitVectorAsHex(OS, Covered, 32);
+  OS << "};\n";
+}
+
+void PrinterLLVM::regInfoEmitGetRegMasks(std::vector<Record *> const &CSRSets,
+                                         std::string const &ClassName) const {
+  OS << "ArrayRef<const uint32_t *> " << ClassName
+     << "::getRegMasks() const {\n";
+  if (!CSRSets.empty()) {
+    OS << "  static const uint32_t *const Masks[] = {\n";
+    for (Record *CSRSet : CSRSets)
+      OS << "    " << CSRSet->getName() << "_RegMask,\n";
+    OS << "  };\n";
+    OS << "  return makeArrayRef(Masks);\n";
+  } else {
+    OS << "  return std::nullopt;\n";
+  }
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitGPRCheck(
+    std::string const &ClassName,
+    std::list<CodeGenRegisterCategory> const &RegCategories) const {
+  OS << "bool " << ClassName << "::\n"
+     << "isGeneralPurposeRegister(const MachineFunction &MF, "
+     << "MCRegister PhysReg) const {\n"
+     << "  return\n";
+  for (const CodeGenRegisterCategory &Category : RegCategories)
+    if (Category.getName() == "GeneralPurposeRegisters") {
+      for (const CodeGenRegisterClass *RC : Category.getClasses())
+        OS << "      " << RC->getQualifiedName()
+           << "RegClass.contains(PhysReg) ||\n";
+      break;
+    }
+  OS << "      false;\n";
+  OS << "}\n\n";
+}
+void PrinterLLVM::regInfoEmitFixedRegCheck(
+    std::string const &ClassName,
+    std::list<CodeGenRegisterCategory> const &RegCategories) const {
+  OS << "bool " << ClassName << "::\n"
+     << "isFixedRegister(const MachineFunction &MF, "
+     << "MCRegister PhysReg) const {\n"
+     << "  return\n";
+  for (const CodeGenRegisterCategory &Category : RegCategories)
+    if (Category.getName() == "FixedRegisters") {
+      for (const CodeGenRegisterClass *RC : Category.getClasses())
+        OS << "      " << RC->getQualifiedName()
+           << "RegClass.contains(PhysReg) ||\n";
+      break;
+    }
+  OS << "      false;\n";
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitArgRegCheck(
+    std::string const &ClassName,
+    std::list<CodeGenRegisterCategory> const &RegCategories) const {
+  OS << "bool " << ClassName << "::\n"
+     << "isArgumentRegister(const MachineFunction &MF, "
+     << "MCRegister PhysReg) const {\n"
+     << "  return\n";
+  for (const CodeGenRegisterCategory &Category : RegCategories)
+    if (Category.getName() == "ArgumentRegisters") {
+      for (const CodeGenRegisterClass *RC : Category.getClasses())
+        OS << "      " << RC->getQualifiedName()
+           << "RegClass.contains(PhysReg) ||\n";
+      break;
+    }
+  OS << "      false;\n";
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitIsConstantPhysReg(
+    std::deque<CodeGenRegister> const &Regs,
+    std::string const &ClassName) const {
+  OS << "bool " << ClassName << "::\n"
+     << "isConstantPhysReg(MCRegister PhysReg) const {\n"
+     << "  return\n";
+  for (const auto &Reg : Regs)
+    if (Reg.Constant)
+      OS << "      PhysReg == " << getQualifiedName(Reg.TheDef) << " ||\n";
+  OS << "      false;\n";
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitGetRegMaskNames(
+    std::vector<Record *> const &CSRSets, std::string const &ClassName) const {
+  OS << "ArrayRef<const char *> " << ClassName
+     << "::getRegMaskNames() const {\n";
+  if (!CSRSets.empty()) {
+    OS << "  static const char *Names[] = {\n";
+    for (Record *CSRSet : CSRSets)
+      OS << "    " << '"' << CSRSet->getName() << '"' << ",\n";
+    OS << "  };\n";
+    OS << "  return makeArrayRef(Names);\n";
+  } else {
+    OS << "  return std::nullopt;\n";
+  }
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitGetFrameLowering(
+    std::string const &TargetName) const {
+  OS << "const " << TargetName << "FrameLowering *\n"
+     << TargetName
+     << "GenRegisterInfo::getFrameLowering(const MachineFunction &MF) {\n"
+     << "  return static_cast<const " << TargetName << "FrameLowering *>(\n"
+     << "      MF.getSubtarget().getFrameLowering());\n"
+     << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitComposeSubRegIndicesImplHead(
+    std::string const &ClName) const {
+  OS << "unsigned " << ClName
+     << "::composeSubRegIndicesImpl(unsigned IdxA, unsigned IdxB) const {\n";
+}
+
+void PrinterLLVM::regInfoEmitComposeSubRegIndicesImplBody(
+    SmallVector<SmallVector<CodeGenSubRegIndex *, 4>, 4> const &Rows,
+    unsigned SubRegIndicesSize, SmallVector<unsigned, 4> const &RowMap) const {
+  if (Rows.size() > 1) {
+    OS << "  static const " << getMinimalTypeForRange(Rows.size(), 32)
+       << " RowMap[" << SubRegIndicesSize << "] = {\n    ";
+    for (unsigned I = 0, E = SubRegIndicesSize; I != E; ++I)
+      OS << RowMap[I] << ", ";
+    OS << "\n  };\n";
+  }
+
+  // Output the rows.
+  OS << "  static const " << getMinimalTypeForRange(SubRegIndicesSize + 1, 32)
+     << " Rows[" << Rows.size() << "][" << SubRegIndicesSize << "] = {\n";
+  for (unsigned R = 0, Re = Rows.size(); R != Re; ++R) {
+    OS << "    { ";
+    for (unsigned I = 0, E = SubRegIndicesSize; I != E; ++I)
+      if (Rows[R][I])
+        OS << Rows[R][I]->getQualifiedName() << ", ";
+      else
+        OS << "0, ";
+    OS << "},\n";
+  }
+  OS << "  };\n\n";
+
+  OS << "  --IdxA; assert(IdxA < " << SubRegIndicesSize << "); (void) IdxA;\n"
+     << "  --IdxB; assert(IdxB < " << SubRegIndicesSize << ");\n";
+  if (Rows.size() > 1)
+    OS << "  return Rows[RowMap[IdxA]][IdxB];\n";
+  else
+    OS << "  return Rows[0][IdxB];\n";
+  OS << "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitLaneMaskComposeSeq(
+    SmallVector<SmallVector<MaskRolPair, 1>, 4> const &Sequences,
+    SmallVector<unsigned, 4> const &SubReg2SequenceIndexMap,
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices) const {
+  OS << "  struct MaskRolOp {\n"
+        "    LaneBitmask Mask;\n"
+        "    uint8_t  RotateLeft;\n"
+        "  };\n"
+        "  static const MaskRolOp LaneMaskComposeSequences[] = {\n";
+  unsigned Idx = 0;
+  for (size_t S = 0, Se = Sequences.size(); S != Se; ++S) {
+    OS << "    ";
+    const SmallVectorImpl<MaskRolPair> &Sequence = Sequences[S];
+    for (size_t P = 0, Pe = Sequence.size(); P != Pe; ++P) {
+      const MaskRolPair &MRP = Sequence[P];
+      printMask(OS << "{ ", MRP.Mask);
+      OS << format(", %2u }, ", MRP.RotateLeft);
+    }
+    OS << "{ LaneBitmask::getNone(), 0 }";
+    if (S + 1 != Se)
+      OS << ", ";
+    OS << "  // Sequence " << Idx << "\n";
+    Idx += Sequence.size() + 1;
+  }
+  auto *IntType = getMinimalTypeForRange(*std::max_element(
+      SubReg2SequenceIndexMap.begin(), SubReg2SequenceIndexMap.end()));
+  OS << "  };\n"
+        "  static const "
+     << IntType << " CompositeSequences[] = {\n";
+  for (size_t I = 0, E = SubRegIndices.size(); I != E; ++I) {
+    OS << "    ";
+    OS << SubReg2SequenceIndexMap[I];
+    if (I + 1 != E)
+      OS << ",";
+    OS << " // to " << SubRegIndices[I].getName() << "\n";
+  }
+  OS << "  };\n\n";
+}
+
+void PrinterLLVM::regInfoEmitComposeSubRegIdxLaneMask(
+    std::string const &ClName,
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices) const {
+  OS << "LaneBitmask " << ClName
+     << "::composeSubRegIndexLaneMaskImpl(unsigned IdxA, "
+        "LaneBitmask LaneMask) const {\n"
+        "  --IdxA; assert(IdxA < "
+     << SubRegIndices.size()
+     << " && \"Subregister index out of bounds\");\n"
+        "  LaneBitmask Result;\n"
+        "  for (const MaskRolOp *Ops =\n"
+        "       &LaneMaskComposeSequences[CompositeSequences[IdxA]];\n"
+        "       Ops->Mask.any(); ++Ops) {\n"
+        "    LaneBitmask::Type M = LaneMask.getAsInteger() & "
+        "Ops->Mask.getAsInteger();\n"
+        "    if (unsigned S = Ops->RotateLeft)\n"
+        "      Result |= LaneBitmask((M << S) | (M >> (LaneBitmask::BitWidth - "
+        "S)));\n"
+        "    else\n"
+        "      Result |= LaneBitmask(M);\n"
+        "  }\n"
+        "  return Result;\n"
+        "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitComposeSubRegIdxLaneMaskRev(
+    std::string const &ClName,
+    std::deque<CodeGenSubRegIndex> const &SubRegIndices) const {
+  OS << "LaneBitmask " << ClName
+     << "::reverseComposeSubRegIndexLaneMaskImpl(unsigned IdxA, "
+        " LaneBitmask LaneMask) const {\n"
+        "  LaneMask &= getSubRegIndexLaneMask(IdxA);\n"
+        "  --IdxA; assert(IdxA < "
+     << SubRegIndices.size()
+     << " && \"Subregister index out of bounds\");\n"
+        "  LaneBitmask Result;\n"
+        "  for (const MaskRolOp *Ops =\n"
+        "       &LaneMaskComposeSequences[CompositeSequences[IdxA]];\n"
+        "       Ops->Mask.any(); ++Ops) {\n"
+        "    LaneBitmask::Type M = LaneMask.getAsInteger();\n"
+        "    if (unsigned S = Ops->RotateLeft)\n"
+        "      Result |= LaneBitmask((M >> S) | (M << (LaneBitmask::BitWidth - "
+        "S)));\n"
+        "    else\n"
+        "      Result |= LaneBitmask(M);\n"
+        "  }\n"
+        "  return Result;\n"
+        "}\n\n";
+}
+
+void PrinterLLVM::regInfoEmitRegBaseClassMapping(
+    std::string const &ClassName,
+    SmallVector<const CodeGenRegisterClass *> const BaseClasses,
+    std::vector<uint8_t> const Mapping) const {
+  OS << "\n// Register to base register class mapping\n\n";
+  OS << "\n";
+  OS << "const TargetRegisterClass *" << ClassName
+     << "::getPhysRegBaseClass(MCRegister Reg)"
+     << " const {\n";
+  OS << "  static const TargetRegisterClass *BaseClasses["
+     << (BaseClasses.size() + 1) << "] = {\n";
+  OS << "    nullptr,\n";
+  for (const auto *const RC : BaseClasses)
+    OS << "    &" << RC->getQualifiedName() << "RegClass,\n";
+  OS << "  };\n";
+  OS << "  static const uint8_t Mapping[" << Mapping.size() << "] = {\n    ";
+  for (const uint8_t Value : Mapping)
+    OS << (unsigned)Value << ",";
+  OS << "  };\n\n";
+  OS << "  assert(Reg < sizeof(Mapping));\n";
+  OS << "  return BaseClasses[Mapping[Reg]];\n";
+  OS << "}\n";
+}
+
+} // end namespace llvm

llvm/utils/TableGen/PrinterTypes.h

+//===------------- PrinterTypes.h - Printer Interface -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_UTILS_TABLEGEN_PRINTERTYPES_H
+#define LLVM_UTILS_TABLEGEN_PRINTERTYPES_H
+
+#include "llvm/ADT/BitVector.h"
+namespace llvm {
+
+enum PrinterLanguage {
+  PRINTER_LANG_CPP,
+  PRINTER_LANG_CAPSTONE_C,
+};
+
+} // end namespace llvm
+
+#endif // LLVM_UTILS_TABLEGEN_PRINTERTYPES_H

llvm/utils/TableGen/RegisterInfoEmitter.cpp

 //===- RegisterInfoEmitter.cpp - Generate a Register File Desc. -*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This tablegen backend is responsible for emitting a description of a target
 // register file for a code generator.  It uses instances of the Register,
 // RegisterAliases, and RegisterClass classes to gather this information.
 //
 //===----------------------------------------------------------------------===//
 
-#include "CodeGenRegisters.h"
-#include "CodeGenTarget.h"
-#include "SequenceToOffsetTable.h"
-#include "Types.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/SparseBitVector.h"
-#include "llvm/ADT/Twine.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Format.h"
-#include "llvm/Support/MachineValueType.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/TableGen/Error.h"
-#include "llvm/TableGen/Record.h"
-#include "llvm/TableGen/SetTheory.h"
-#include "llvm/TableGen/TableGenBackend.h"
-#include <algorithm>
-#include <cassert>
-#include <cstddef>
-#include <cstdint>
-#include <deque>
-#include <iterator>
-#include <set>
-#include <string>
-#include <vector>
+#include "Printer.h"
+#include "RegisterInfoEmitterTypes.h"
 
 using namespace llvm;
 
 cl::OptionCategory RegisterInfoCat("Options for -gen-register-info");
 
 static cl::opt<bool>
     RegisterInfoDebug("register-info-debug", cl::init(false),
                       cl::desc("Dump register information to help debugging"),
                       cl::cat(RegisterInfoCat));
 
 namespace {
 
 class RegisterInfoEmitter {
   CodeGenTarget Target;
   RecordKeeper &Records;
+  PrinterLLVM &PI;
 
 public:
-  RegisterInfoEmitter(RecordKeeper &R) : Target(R), Records(R) {
+  RegisterInfoEmitter(RecordKeeper &R, PrinterLLVM &PI)
+      : Target(R), Records(R), PI(PI) {
     CodeGenRegBank &RegBank = Target.getRegBank();
     RegBank.computeDerivedInfo();
   }
 
-  // runEnums - Print out enum values for all of the registers.
-  void runEnums(raw_ostream &o, CodeGenTarget &Target, CodeGenRegBank &Bank);
-
   // runMCDesc - Print out MC register descriptions.
-  void runMCDesc(raw_ostream &o, CodeGenTarget &Target, CodeGenRegBank &Bank);
+  void runMCDesc(CodeGenTarget &Target, CodeGenRegBank &Bank);
 
   // runTargetHeader - Emit a header fragment for the register info emitter.
-  void runTargetHeader(raw_ostream &o, CodeGenTarget &Target,
+  void runTargetHeader(CodeGenTarget &Target,
                        CodeGenRegBank &Bank);
 
   // runTargetDesc - Output the target register and register file descriptions.
-  void runTargetDesc(raw_ostream &o, CodeGenTarget &Target,
+  void runTargetDesc(CodeGenTarget &Target,
                      CodeGenRegBank &Bank);
 
   // run - Output the register file description.
-  void run(raw_ostream &o);
+  void run();
 
   void debugDump(raw_ostream &OS);
 
 private:
-  void EmitRegMapping(raw_ostream &o, const std::deque<CodeGenRegister> &Regs,
+  void EmitRegMapping(const std::deque<CodeGenRegister> &Regs,
                       bool isCtor);
-  void EmitRegMappingTables(raw_ostream &o,
-                            const std::deque<CodeGenRegister> &Regs,
+  void EmitRegMappingTables(const std::deque<CodeGenRegister> &Regs,
                             bool isCtor);
-  void EmitRegUnitPressure(raw_ostream &OS, const CodeGenRegBank &RegBank,
+  void EmitRegUnitPressure(const CodeGenRegBank &RegBank,
                            const std::string &ClassName);
-  void emitComposeSubRegIndices(raw_ostream &OS, CodeGenRegBank &RegBank,
+  void emitComposeSubRegIndices(CodeGenRegBank &RegBank,
                                 const std::string &ClassName);
-  void emitComposeSubRegIndexLaneMask(raw_ostream &OS, CodeGenRegBank &RegBank,
+  void emitComposeSubRegIndexLaneMask(CodeGenRegBank &RegBank,
                                       const std::string &ClassName);
 };
 
 } // end anonymous namespace
 
-// runEnums - Print out enum values for all of the registers.
-void RegisterInfoEmitter::runEnums(raw_ostream &OS,
-                                   CodeGenTarget &Target, CodeGenRegBank &Bank) {
-  const auto &Registers = Bank.getRegisters();
-
-  // Register enums are stored as uint16_t in the tables. Make sure we'll fit.
-  assert(Registers.size() <= 0xffff && "Too many regs to fit in tables");
-
-  StringRef Namespace = Registers.front().TheDef->getValueAsString("Namespace");
-
-  emitSourceFileHeader("Target Register Enum Values", OS);
-
-  OS << "\n#ifdef GET_REGINFO_ENUM\n";
-  OS << "#undef GET_REGINFO_ENUM\n\n";
-
-  OS << "namespace llvm {\n\n";
-
-  OS << "class MCRegisterClass;\n"
-     << "extern const MCRegisterClass " << Target.getName()
-     << "MCRegisterClasses[];\n\n";
-
-  if (!Namespace.empty())
-    OS << "namespace " << Namespace << " {\n";
-  OS << "enum {\n  NoRegister,\n";
-
-  for (const auto &Reg : Registers)
-    OS << "  " << Reg.getName() << " = " << Reg.EnumValue << ",\n";
-  assert(Registers.size() == Registers.back().EnumValue &&
-         "Register enum value mismatch!");
-  OS << "  NUM_TARGET_REGS // " << Registers.size()+1 << "\n";
-  OS << "};\n";
-  if (!Namespace.empty())
-    OS << "} // end namespace " << Namespace << "\n";
-
-  const auto &RegisterClasses = Bank.getRegClasses();
-  if (!RegisterClasses.empty()) {
-
-    // RegisterClass enums are stored as uint16_t in the tables.
-    assert(RegisterClasses.size() <= 0xffff &&
-           "Too many register classes to fit in tables");
-
-    OS << "\n// Register classes\n\n";
-    if (!Namespace.empty())
-      OS << "namespace " << Namespace << " {\n";
-    OS << "enum {\n";
-    for (const auto &RC : RegisterClasses)
-      OS << "  " << RC.getName() << "RegClassID"
-         << " = " << RC.EnumValue << ",\n";
-    OS << "\n};\n";
-    if (!Namespace.empty())
-      OS << "} // end namespace " << Namespace << "\n\n";
-  }
-
-  const std::vector<Record*> &RegAltNameIndices = Target.getRegAltNameIndices();
-  // If the only definition is the default NoRegAltName, we don't need to
-  // emit anything.
-  if (RegAltNameIndices.size() > 1) {
-    OS << "\n// Register alternate name indices\n\n";
-    if (!Namespace.empty())
-      OS << "namespace " << Namespace << " {\n";
-    OS << "enum {\n";
-    for (unsigned i = 0, e = RegAltNameIndices.size(); i != e; ++i)
-      OS << "  " << RegAltNameIndices[i]->getName() << ",\t// " << i << "\n";
-    OS << "  NUM_TARGET_REG_ALT_NAMES = " << RegAltNameIndices.size() << "\n";
-    OS << "};\n";
-    if (!Namespace.empty())
-      OS << "} // end namespace " << Namespace << "\n\n";
-  }
-
-  auto &SubRegIndices = Bank.getSubRegIndices();
-  if (!SubRegIndices.empty()) {
-    OS << "\n// Subregister indices\n\n";
-    std::string Namespace = SubRegIndices.front().getNamespace();
-    if (!Namespace.empty())
-      OS << "namespace " << Namespace << " {\n";
-    OS << "enum : uint16_t {\n  NoSubRegister,\n";
-    unsigned i = 0;
-    for (const auto &Idx : SubRegIndices)
-      OS << "  " << Idx.getName() << ",\t// " << ++i << "\n";
-    OS << "  NUM_TARGET_SUBREGS\n};\n";
-    if (!Namespace.empty())
-      OS << "} // end namespace " << Namespace << "\n\n";
-  }
-
-  OS << "// Register pressure sets enum.\n";
-  if (!Namespace.empty())
-    OS << "namespace " << Namespace << " {\n";
-  OS << "enum RegisterPressureSets {\n";
-  unsigned NumSets = Bank.getNumRegPressureSets();
-  for (unsigned i = 0; i < NumSets; ++i ) {
-    const RegUnitSet &RegUnits = Bank.getRegSetAt(i);
-    OS << "  " << RegUnits.Name << " = " << i << ",\n";
-  }
-  OS << "};\n";
-  if (!Namespace.empty())
-    OS << "} // end namespace " << Namespace << '\n';
-  OS << '\n';
-
-  OS << "} // end namespace llvm\n\n";
-  OS << "#endif // GET_REGINFO_ENUM\n\n";
-}
-
-static void printInt(raw_ostream &OS, int Val) {
-  OS << Val;
-}
-
 void RegisterInfoEmitter::
-EmitRegUnitPressure(raw_ostream &OS, const CodeGenRegBank &RegBank,
+EmitRegUnitPressure(const CodeGenRegBank &RegBank,
                     const std::string &ClassName) {
   unsigned NumRCs = RegBank.getRegClasses().size();
   unsigned NumSets = RegBank.getNumRegPressureSets();
 
-  OS << "/// Get the weight in units of pressure for this register class.\n"
-     << "const RegClassWeight &" << ClassName << "::\n"
-     << "getRegClassWeight(const TargetRegisterClass *RC) const {\n"
-     << "  static const RegClassWeight RCWeightTable[] = {\n";
-  for (const auto &RC : RegBank.getRegClasses()) {
-    const CodeGenRegister::Vec &Regs = RC.getMembers();
-    OS << "    {" << RC.getWeight(RegBank) << ", ";
-    if (Regs.empty() || RC.Artificial)
-      OS << '0';
-    else {
-      std::vector<unsigned> RegUnits;
-      RC.buildRegUnitSet(RegBank, RegUnits);
-      OS << RegBank.getRegUnitSetWeight(RegUnits);
-    }
-    OS << "},  \t// " << RC.getName() << "\n";
-  }
-  OS << "  };\n"
-     << "  return RCWeightTable[RC->getID()];\n"
-     << "}\n\n";
-
+  PI.regInfoEmitRegClassWeight(RegBank, ClassName);
   // Reasonable targets (not ARMv7) have unit weight for all units, so don't
   // bother generating a table.
   bool RegUnitsHaveUnitWeight = true;
   for (unsigned UnitIdx = 0, UnitEnd = RegBank.getNumNativeRegUnits();
        UnitIdx < UnitEnd; ++UnitIdx) {
     if (RegBank.getRegUnit(UnitIdx).Weight > 1)
       RegUnitsHaveUnitWeight = false;
   }
-  OS << "/// Get the weight in units of pressure for this register unit.\n"
-     << "unsigned " << ClassName << "::\n"
-     << "getRegUnitWeight(unsigned RegUnit) const {\n"
-     << "  assert(RegUnit < " << RegBank.getNumNativeRegUnits()
-     << " && \"invalid register unit\");\n";
-  if (!RegUnitsHaveUnitWeight) {
-    OS << "  static const uint8_t RUWeightTable[] = {\n    ";
-    for (unsigned UnitIdx = 0, UnitEnd = RegBank.getNumNativeRegUnits();
-         UnitIdx < UnitEnd; ++UnitIdx) {
-      const RegUnit &RU = RegBank.getRegUnit(UnitIdx);
-      assert(RU.Weight < 256 && "RegUnit too heavy");
-      OS << RU.Weight << ", ";
-    }
-    OS << "};\n"
-       << "  return RUWeightTable[RegUnit];\n";
-  }
-  else {
-    OS << "  // All register units have unit weight.\n"
-       << "  return 1;\n";
-  }
-  OS << "}\n\n";
-
-  OS << "\n"
-     << "// Get the number of dimensions of register pressure.\n"
-     << "unsigned " << ClassName << "::getNumRegPressureSets() const {\n"
-     << "  return " << NumSets << ";\n}\n\n";
-
-  OS << "// Get the name of this register unit pressure set.\n"
-     << "const char *" << ClassName << "::\n"
-     << "getRegPressureSetName(unsigned Idx) const {\n"
-     << "  static const char *PressureNameTable[] = {\n";
-  unsigned MaxRegUnitWeight = 0;
-  for (unsigned i = 0; i < NumSets; ++i ) {
-    const RegUnitSet &RegUnits = RegBank.getRegSetAt(i);
-    MaxRegUnitWeight = std::max(MaxRegUnitWeight, RegUnits.Weight);
-    OS << "    \"" << RegUnits.Name << "\",\n";
-  }
-  OS << "  };\n"
-     << "  return PressureNameTable[Idx];\n"
-     << "}\n\n";
-
-  OS << "// Get the register unit pressure limit for this dimension.\n"
-     << "// This limit must be adjusted dynamically for reserved registers.\n"
-     << "unsigned " << ClassName << "::\n"
-     << "getRegPressureSetLimit(const MachineFunction &MF, unsigned Idx) const "
-        "{\n"
-     << "  static const " << getMinimalTypeForRange(MaxRegUnitWeight, 32)
-     << " PressureLimitTable[] = {\n";
-  for (unsigned i = 0; i < NumSets; ++i ) {
-    const RegUnitSet &RegUnits = RegBank.getRegSetAt(i);
-    OS << "    " << RegUnits.Weight << ",  \t// " << i << ": "
-       << RegUnits.Name << "\n";
-  }
-  OS << "  };\n"
-     << "  return PressureLimitTable[Idx];\n"
-     << "}\n\n";
+  PI.regInfoEmitRegUnitWeight(RegBank, ClassName, RegUnitsHaveUnitWeight);
+  PI.regInfoEmitGetNumRegPressureSets(ClassName, NumSets);
+  PI.regInfoEmitGetRegPressureTables(RegBank, ClassName, NumSets);
 
-  SequenceToOffsetTable<std::vector<int>> PSetsSeqs;
+  SequenceToOffsetTable<std::vector<int>> PSetsSeqs(PI.getLanguage());
 
   // This table may be larger than NumRCs if some register units needed a list
   // of unit sets that did not correspond to a register class.
   unsigned NumRCUnitSets = RegBank.getNumRegClassPressureSetLists();
   std::vector<std::vector<int>> PSets(NumRCUnitSets);
 
   for (unsigned i = 0, e = NumRCUnitSets; i != e; ++i) {
     ArrayRef<unsigned> PSetIDs = RegBank.getRCPressureSetIDs(i);
     PSets[i].reserve(PSetIDs.size());
     for (unsigned PSetID : PSetIDs) {
       PSets[i].push_back(RegBank.getRegPressureSet(PSetID).Order);
     }
     llvm::sort(PSets[i]);
     PSetsSeqs.add(PSets[i]);
   }
 
   PSetsSeqs.layout();
-
-  OS << "/// Table of pressure sets per register class or unit.\n"
-     << "static const int RCSetsTable[] = {\n";
-  PSetsSeqs.emit(OS, printInt, "-1");
-  OS << "};\n\n";
-
-  OS << "/// Get the dimensions of register pressure impacted by this "
-     << "register class.\n"
-     << "/// Returns a -1 terminated array of pressure set IDs\n"
-     << "const int *" << ClassName << "::\n"
-     << "getRegClassPressureSets(const TargetRegisterClass *RC) const {\n";
-  OS << "  static const " << getMinimalTypeForRange(PSetsSeqs.size() - 1, 32)
-     << " RCSetStartTable[] = {\n    ";
-  for (unsigned i = 0, e = NumRCs; i != e; ++i) {
-    OS << PSetsSeqs.get(PSets[i]) << ",";
-  }
-  OS << "};\n"
-     << "  return &RCSetsTable[RCSetStartTable[RC->getID()]];\n"
-     << "}\n\n";
-
-  OS << "/// Get the dimensions of register pressure impacted by this "
-     << "register unit.\n"
-     << "/// Returns a -1 terminated array of pressure set IDs\n"
-     << "const int *" << ClassName << "::\n"
-     << "getRegUnitPressureSets(unsigned RegUnit) const {\n"
-     << "  assert(RegUnit < " << RegBank.getNumNativeRegUnits()
-     << " && \"invalid register unit\");\n";
-  OS << "  static const " << getMinimalTypeForRange(PSetsSeqs.size() - 1, 32)
-     << " RUSetStartTable[] = {\n    ";
-  for (unsigned UnitIdx = 0, UnitEnd = RegBank.getNumNativeRegUnits();
-       UnitIdx < UnitEnd; ++UnitIdx) {
-    OS << PSetsSeqs.get(PSets[RegBank.getRegUnit(UnitIdx).RegClassUnitSetsIdx])
-       << ",";
-  }
-  OS << "};\n"
-     << "  return &RCSetsTable[RUSetStartTable[RegUnit]];\n"
-     << "}\n\n";
+  PI.regInfoEmitRCSetsTable(ClassName, NumRCs, PSetsSeqs, PSets);
+  PI.regInfoEmitGetRegUnitPressureSets(PSetsSeqs, RegBank,
+                                       ClassName, PSets);
 }
 
-using DwarfRegNumsMapPair = std::pair<Record*, std::vector<int64_t>>;
-using DwarfRegNumsVecTy = std::vector<DwarfRegNumsMapPair>;
-
 static void finalizeDwarfRegNumsKeys(DwarfRegNumsVecTy &DwarfRegNums) {
   // Sort and unique to get a map-like vector. We want the last assignment to
   // match previous behaviour.
   llvm::stable_sort(DwarfRegNums, on_first<LessRecordRegister>());
   // Warn about duplicate assignments.
   const Record *LastSeenReg = nullptr;
   for (const auto &X : DwarfRegNums) {
     const auto &Reg = X.first;
auto Last = std::unique(
       DwarfRegNums.begin(), DwarfRegNums.end(),
       [](const DwarfRegNumsMapPair &A, const DwarfRegNumsMapPair &B) {
         return A.first->getName() == B.first->getName();
       });
   DwarfRegNums.erase(Last, DwarfRegNums.end());
 }
 
 void RegisterInfoEmitter::EmitRegMappingTables(
-    raw_ostream &OS, const std::deque<CodeGenRegister> &Regs, bool isCtor) {
+    const std::deque<CodeGenRegister> &Regs, bool isCtor) {
   // Collect all information about dwarf register numbers
   DwarfRegNumsVecTy DwarfRegNums;
 
   // First, just pull all provided information to the map
   unsigned maxLength = 0;
   for (auto &RE : Regs) {
     Record *Reg = RE.TheDef;
     std::vector<int64_t> RegNums = Reg->getValueAsListOfInts("DwarfNumbers");
     maxLength = std::max((size_t)maxLength, RegNums.size());
     DwarfRegNums.emplace_back(Reg, std::move(RegNums));
   }
   finalizeDwarfRegNumsKeys(DwarfRegNums);
 
   if (!maxLength)
     return;
 
   // Now we know maximal length of number list. Append -1's, where needed
   for (auto &DwarfRegNum : DwarfRegNums)
     for (unsigned I = DwarfRegNum.second.size(), E = maxLength; I != E; ++I)
       DwarfRegNum.second.push_back(-1);
 
   StringRef Namespace = Regs.front().TheDef->getValueAsString("Namespace");
-
-  OS << "// " << Namespace << " Dwarf<->LLVM register mappings.\n";
-
-  // Emit reverse information about the dwarf register numbers.
-  for (unsigned j = 0; j < 2; ++j) {
-    for (unsigned I = 0, E = maxLength; I != E; ++I) {
-      OS << "extern const MCRegisterInfo::DwarfLLVMRegPair " << Namespace;
-      OS << (j == 0 ? "DwarfFlavour" : "EHFlavour");
-      OS << I << "Dwarf2L[]";
-
-      if (!isCtor) {
-        OS << " = {\n";
-
-        // Store the mapping sorted by the LLVM reg num so lookup can be done
-        // with a binary search.
-        std::map<uint64_t, Record*> Dwarf2LMap;
-        for (auto &DwarfRegNum : DwarfRegNums) {
-          int DwarfRegNo = DwarfRegNum.second[I];
-          if (DwarfRegNo < 0)
-            continue;
-          Dwarf2LMap[DwarfRegNo] = DwarfRegNum.first;
-        }
-
-        for (auto &I : Dwarf2LMap)
-          OS << "  { " << I.first << "U, " << getQualifiedName(I.second)
-             << " },\n";
-
-        OS << "};\n";
-      } else {
-        OS << ";\n";
-      }
-
-      // We have to store the size in a const global, it's used in multiple
-      // places.
-      OS << "extern const unsigned " << Namespace
-         << (j == 0 ? "DwarfFlavour" : "EHFlavour") << I << "Dwarf2LSize";
-      if (!isCtor)
-        OS << " = std::size(" << Namespace
-           << (j == 0 ? "DwarfFlavour" : "EHFlavour") << I << "Dwarf2L);\n\n";
-      else
-        OS << ";\n\n";
-    }
-  }
+  PI.regInfoEmitInfoDwarfRegsRev(Namespace, DwarfRegNums, maxLength, isCtor);
 
   for (auto &RE : Regs) {
     Record *Reg = RE.TheDef;
     const RecordVal *V = Reg->getValue("DwarfAlias");
     if (!V || !V->getValue())
       continue;
 
     DefInit *DI = cast<DefInit>(V->getValue());
const auto &RegIter = llvm::lower_bound(
           return LessRecordRegister()(A.first, B);
         });
     assert(RegIter != DwarfRegNums.end() && RegIter->first == Reg &&
            "Expected Reg to be present in map");
     RegIter->second = AliasIter->second;
   }
 
   // Emit information about the dwarf register numbers.
-  for (unsigned j = 0; j < 2; ++j) {
-    for (unsigned i = 0, e = maxLength; i != e; ++i) {
-      OS << "extern const MCRegisterInfo::DwarfLLVMRegPair " << Namespace;
-      OS << (j == 0 ? "DwarfFlavour" : "EHFlavour");
-      OS << i << "L2Dwarf[]";
-      if (!isCtor) {
-        OS << " = {\n";
-        // Store the mapping sorted by the Dwarf reg num so lookup can be done
-        // with a binary search.
-        for (auto &DwarfRegNum : DwarfRegNums) {
-          int RegNo = DwarfRegNum.second[i];
-          if (RegNo == -1) // -1 is the default value, don't emit a mapping.
-            continue;
-
-          OS << "  { " << getQualifiedName(DwarfRegNum.first) << ", " << RegNo
-             << "U },\n";
-        }
-        OS << "};\n";
-      } else {
-        OS << ";\n";
-      }
-
-      // We have to store the size in a const global, it's used in multiple
-      // places.
-      OS << "extern const unsigned " << Namespace
-         << (j == 0 ? "DwarfFlavour" : "EHFlavour") << i << "L2DwarfSize";
-      if (!isCtor)
-        OS << " = std::size(" << Namespace
-           << (j == 0 ? "DwarfFlavour" : "EHFlavour") << i << "L2Dwarf);\n\n";
-      else
-        OS << ";\n\n";
-    }
-  }
+  PI.regInfoEmitInfoDwarfRegs(Namespace, DwarfRegNums, maxLength, isCtor);
 }
 
 void RegisterInfoEmitter::EmitRegMapping(
-    raw_ostream &OS, const std::deque<CodeGenRegister> &Regs, bool isCtor) {
+    const std::deque<CodeGenRegister> &Regs, bool isCtor) {
   // Emit the initializer so the tables from EmitRegMappingTables get wired up
   // to the MCRegisterInfo object.
   unsigned maxLength = 0;
   for (auto &RE : Regs) {
     Record *Reg = RE.TheDef;
     maxLength = std::max((size_t)maxLength,
                          Reg->getValueAsListOfInts("DwarfNumbers").size());
   }
 
-  if (!maxLength)
-    return;
-
   StringRef Namespace = Regs.front().TheDef->getValueAsString("Namespace");
-
-  // Emit reverse information about the dwarf register numbers.
-  for (unsigned j = 0; j < 2; ++j) {
-    OS << "  switch (";
-    if (j == 0)
-      OS << "DwarfFlavour";
-    else
-      OS << "EHFlavour";
-    OS << ") {\n"
-     << "  default:\n"
-     << "    llvm_unreachable(\"Unknown DWARF flavour\");\n";
-
-    for (unsigned i = 0, e = maxLength; i != e; ++i) {
-      OS << "  case " << i << ":\n";
-      OS << "    ";
-      if (!isCtor)
-        OS << "RI->";
-      std::string Tmp;
-      raw_string_ostream(Tmp) << Namespace
-                              << (j == 0 ? "DwarfFlavour" : "EHFlavour") << i
-                              << "Dwarf2L";
-      OS << "mapDwarfRegsToLLVMRegs(" << Tmp << ", " << Tmp << "Size, ";
-      if (j == 0)
-          OS << "false";
-        else
-          OS << "true";
-      OS << ");\n";
-      OS << "    break;\n";
-    }
-    OS << "  }\n";
-  }
-
-  // Emit information about the dwarf register numbers.
-  for (unsigned j = 0; j < 2; ++j) {
-    OS << "  switch (";
-    if (j == 0)
-      OS << "DwarfFlavour";
-    else
-      OS << "EHFlavour";
-    OS << ") {\n"
-       << "  default:\n"
-       << "    llvm_unreachable(\"Unknown DWARF flavour\");\n";
-
-    for (unsigned i = 0, e = maxLength; i != e; ++i) {
-      OS << "  case " << i << ":\n";
-      OS << "    ";
-      if (!isCtor)
-        OS << "RI->";
-      std::string Tmp;
-      raw_string_ostream(Tmp) << Namespace
-                              << (j == 0 ? "DwarfFlavour" : "EHFlavour") << i
-                              << "L2Dwarf";
-      OS << "mapLLVMRegsToDwarfRegs(" << Tmp << ", " << Tmp << "Size, ";
-      if (j == 0)
-          OS << "false";
-        else
-          OS << "true";
-      OS << ");\n";
-      OS << "    break;\n";
-    }
-    OS << "  }\n";
-  }
-}
-
-// Print a BitVector as a sequence of hex numbers using a little-endian mapping.
-// Width is the number of bits per hex number.
-static void printBitVectorAsHex(raw_ostream &OS,
-                                const BitVector &Bits,
-                                unsigned Width) {
-  assert(Width <= 32 && "Width too large");
-  unsigned Digits = (Width + 3) / 4;
-  for (unsigned i = 0, e = Bits.size(); i < e; i += Width) {
-    unsigned Value = 0;
-    for (unsigned j = 0; j != Width && i + j != e; ++j)
-      Value |= Bits.test(i + j) << j;
-    OS << format("0x%0*x, ", Digits, Value);
-  }
-}
-
-// Helper to emit a set of bits into a constant byte array.
-class BitVectorEmitter {
-  BitVector Values;
-public:
-  void add(unsigned v) {
-    if (v >= Values.size())
-      Values.resize(((v/8)+1)*8); // Round up to the next byte.
-    Values[v] = true;
-  }
-
-  void print(raw_ostream &OS) {
-    printBitVectorAsHex(OS, Values, 8);
-  }
-};
-
-static void printSimpleValueType(raw_ostream &OS, MVT::SimpleValueType VT) {
-  OS << getEnumName(VT);
-}
-
-static void printSubRegIndex(raw_ostream &OS, const CodeGenSubRegIndex *Idx) {
-  OS << Idx->EnumValue;
-}
-
-// Differentially encoded register and regunit lists allow for better
-// compression on regular register banks. The sequence is computed from the
-// differential list as:
-//
-//   out[0] = InitVal;
-//   out[n+1] = out[n] + diff[n]; // n = 0, 1, ...
-//
-// The initial value depends on the specific list. The list is terminated by a
-// 0 differential which means we can't encode repeated elements.
-
-typedef SmallVector<uint16_t, 4> DiffVec;
-typedef SmallVector<LaneBitmask, 4> MaskVec;
+  PI.regInfoEmitInfoRegMapping(Namespace, maxLength, isCtor);
 
 // Differentially encode a sequence of numbers into V. The starting value and
 // terminating 0 are not added to V, so it will have the same size as List.
 static
 DiffVec &diffEncode(DiffVec &V, unsigned InitVal, SparseBitVector<> List) {
   assert(V.empty() && "Clear DiffVec before diffEncode.");
   uint16_t Val = uint16_t(InitVal);
 
DiffVec &diffEncode(DiffVec &V, unsigned InitVal, Iter Begin, Iter End) {
   for (Iter I = Begin; I != End; ++I) {
     uint16_t Cur = (*I)->EnumValue;
     V.push_back(Cur - Val);
     Val = Cur;
   }
   return V;
 }
 
-static void printDiff16(raw_ostream &OS, uint16_t Val) {
-  OS << Val;
-}
-
-static void printMask(raw_ostream &OS, LaneBitmask Val) {
-  OS << "LaneBitmask(0x" << PrintLaneMask(Val) << ')';
-}
-
 // Try to combine Idx's compose map into Vec if it is compatible.
 // Return false if it's not possible.
 static bool combine(const CodeGenSubRegIndex *Idx,
                     SmallVectorImpl<CodeGenSubRegIndex*> &Vec) {
   const CodeGenSubRegIndex::CompMap &Map = Idx->getComposites();
   for (const auto &I : Map) {
     CodeGenSubRegIndex *&Entry = Vec[I.first->EnumValue - 1];
     if (Entry && Entry != I.second)
       return false;
   }
 
   // All entries are compatible. Make it so.
   for (const auto &I : Map) {
     auto *&Entry = Vec[I.first->EnumValue - 1];
     assert((!Entry || Entry == I.second) &&
            "Expected EnumValue to be unique");
     Entry = I.second;
   }
   return true;
 }
 
 void
-RegisterInfoEmitter::emitComposeSubRegIndices(raw_ostream &OS,
-                                              CodeGenRegBank &RegBank,
+RegisterInfoEmitter::emitComposeSubRegIndices(CodeGenRegBank &RegBank,
                                               const std::string &ClName) {
   const auto &SubRegIndices = RegBank.getSubRegIndices();
-  OS << "unsigned " << ClName
-     << "::composeSubRegIndicesImpl(unsigned IdxA, unsigned IdxB) const {\n";
-
+  PI.regInfoEmitComposeSubRegIndicesImplHead(ClName);
   // Many sub-register indexes are composition-compatible, meaning that
   //
   //   compose(IdxA, IdxB) == compose(IdxA', IdxB)
   //
   // for many IdxA, IdxA' pairs. Not all sub-register indexes can be composed.
   // The illegal entries can be use as wildcards to compress the table further.
 
   // Map each Sub-register index to a compatible table row.
if (Found == ~0u) {
       Rows.resize(Found + 1);
       Rows.back().resize(SubRegIndicesSize);
       combine(&Idx, Rows.back());
     }
     RowMap.push_back(Found);
   }
 
   // Output the row map if there is multiple rows.
-  if (Rows.size() > 1) {
-    OS << "  static const " << getMinimalTypeForRange(Rows.size(), 32)
-       << " RowMap[" << SubRegIndicesSize << "] = {\n    ";
-    for (unsigned i = 0, e = SubRegIndicesSize; i != e; ++i)
-      OS << RowMap[i] << ", ";
-    OS << "\n  };\n";
-  }
-
-  // Output the rows.
-  OS << "  static const " << getMinimalTypeForRange(SubRegIndicesSize + 1, 32)
-     << " Rows[" << Rows.size() << "][" << SubRegIndicesSize << "] = {\n";
-  for (unsigned r = 0, re = Rows.size(); r != re; ++r) {
-    OS << "    { ";
-    for (unsigned i = 0, e = SubRegIndicesSize; i != e; ++i)
-      if (Rows[r][i])
-        OS << Rows[r][i]->getQualifiedName() << ", ";
-      else
-        OS << "0, ";
-    OS << "},\n";
-  }
-  OS << "  };\n\n";
-
-  OS << "  --IdxA; assert(IdxA < " << SubRegIndicesSize << "); (void) IdxA;\n"
-     << "  --IdxB; assert(IdxB < " << SubRegIndicesSize << ");\n";
-  if (Rows.size() > 1)
-    OS << "  return Rows[RowMap[IdxA]][IdxB];\n";
-  else
-    OS << "  return Rows[0][IdxB];\n";
-  OS << "}\n\n";
+  PI.regInfoEmitComposeSubRegIndicesImplBody(Rows, SubRegIndicesSize, RowMap);
 }
 
 void
-RegisterInfoEmitter::emitComposeSubRegIndexLaneMask(raw_ostream &OS,
-                                                    CodeGenRegBank &RegBank,
+RegisterInfoEmitter::emitComposeSubRegIndexLaneMask(CodeGenRegBank &RegBank,
                                                     const std::string &ClName) {
   // See the comments in computeSubRegLaneMasks() for our goal here.
   const auto &SubRegIndices = RegBank.getSubRegIndices();
 
   // Create a list of Mask+Rotate operations, with equivalent entries merged.
   SmallVector<unsigned, 4> SubReg2SequenceIndexMap;
   SmallVector<SmallVector<MaskRolPair, 1>, 4> Sequences;
   for (const auto &Idx : SubRegIndices) {
for (const auto &Idx : SubRegIndices) {
     }
     if (Found == ~0u) {
       Sequences.push_back(IdxSequence);
       Found = SIdx;
     }
     SubReg2SequenceIndexMap.push_back(Found);
   }
 
-  OS << "  struct MaskRolOp {\n"
-        "    LaneBitmask Mask;\n"
-        "    uint8_t  RotateLeft;\n"
-        "  };\n"
-        "  static const MaskRolOp LaneMaskComposeSequences[] = {\n";
-  unsigned Idx = 0;
-  for (size_t s = 0, se = Sequences.size(); s != se; ++s) {
-    OS << "    ";
-    const SmallVectorImpl<MaskRolPair> &Sequence = Sequences[s];
-    for (size_t p = 0, pe = Sequence.size(); p != pe; ++p) {
-      const MaskRolPair &P = Sequence[p];
-      printMask(OS << "{ ", P.Mask);
-      OS << format(", %2u }, ", P.RotateLeft);
-    }
-    OS << "{ LaneBitmask::getNone(), 0 }";
-    if (s+1 != se)
-      OS << ", ";
-    OS << "  // Sequence " << Idx << "\n";
-    Idx += Sequence.size() + 1;
-  }
-  auto *IntType = getMinimalTypeForRange(*std::max_element(
-      SubReg2SequenceIndexMap.begin(), SubReg2SequenceIndexMap.end()));
-  OS << "  };\n"
-        "  static const "
-     << IntType << " CompositeSequences[] = {\n";
-  for (size_t i = 0, e = SubRegIndices.size(); i != e; ++i) {
-    OS << "    ";
-    OS << SubReg2SequenceIndexMap[i];
-    if (i+1 != e)
-      OS << ",";
-    OS << " // to " << SubRegIndices[i].getName() << "\n";
-  }
-  OS << "  };\n\n";
-
-  OS << "LaneBitmask " << ClName
-     << "::composeSubRegIndexLaneMaskImpl(unsigned IdxA, LaneBitmask LaneMask)"
-        " const {\n"
-        "  --IdxA; assert(IdxA < " << SubRegIndices.size()
-     << " && \"Subregister index out of bounds\");\n"
-        "  LaneBitmask Result;\n"
-        "  for (const MaskRolOp *Ops =\n"
-        "       &LaneMaskComposeSequences[CompositeSequences[IdxA]];\n"
-        "       Ops->Mask.any(); ++Ops) {\n"
-        "    LaneBitmask::Type M = LaneMask.getAsInteger() & Ops->Mask.getAsInteger();\n"
-        "    if (unsigned S = Ops->RotateLeft)\n"
-        "      Result |= LaneBitmask((M << S) | (M >> (LaneBitmask::BitWidth - S)));\n"
-        "    else\n"
-        "      Result |= LaneBitmask(M);\n"
-        "  }\n"
-        "  return Result;\n"
-        "}\n\n";
-
-  OS << "LaneBitmask " << ClName
-     << "::reverseComposeSubRegIndexLaneMaskImpl(unsigned IdxA, "
-        " LaneBitmask LaneMask) const {\n"
-        "  LaneMask &= getSubRegIndexLaneMask(IdxA);\n"
-        "  --IdxA; assert(IdxA < " << SubRegIndices.size()
-     << " && \"Subregister index out of bounds\");\n"
-        "  LaneBitmask Result;\n"
-        "  for (const MaskRolOp *Ops =\n"
-        "       &LaneMaskComposeSequences[CompositeSequences[IdxA]];\n"
-        "       Ops->Mask.any(); ++Ops) {\n"
-        "    LaneBitmask::Type M = LaneMask.getAsInteger();\n"
-        "    if (unsigned S = Ops->RotateLeft)\n"
-        "      Result |= LaneBitmask((M >> S) | (M << (LaneBitmask::BitWidth - S)));\n"
-        "    else\n"
-        "      Result |= LaneBitmask(M);\n"
-        "  }\n"
-        "  return Result;\n"
-        "}\n\n";
+  PI.regInfoEmitLaneMaskComposeSeq(Sequences, SubReg2SequenceIndexMap, SubRegIndices);
+  PI.regInfoEmitComposeSubRegIdxLaneMask(ClName, SubRegIndices);
+  PI.regInfoEmitComposeSubRegIdxLaneMaskRev(ClName, SubRegIndices);
+
 }
 
 //
 // runMCDesc - Print out MC register descriptions.
 //
 void
-RegisterInfoEmitter::runMCDesc(raw_ostream &OS, CodeGenTarget &Target,
+RegisterInfoEmitter::runMCDesc(CodeGenTarget &Target,
                                CodeGenRegBank &RegBank) {
-  emitSourceFileHeader("MC Register Information", OS);
-
-  OS << "\n#ifdef GET_REGINFO_MC_DESC\n";
-  OS << "#undef GET_REGINFO_MC_DESC\n\n";
+  PI.regInfoEmitSourceFileHeader("MC Register Information");
 
   const auto &Regs = RegBank.getRegisters();
 
   auto &SubRegIndices = RegBank.getSubRegIndices();
-  // The lists of sub-registers and super-registers go in the same array.  That
-  // allows us to share suffixes.
-  typedef std::vector<const CodeGenRegister*> RegVec;
 
   // Differentially encoded lists.
-  SequenceToOffsetTable<DiffVec> DiffSeqs;
+  SequenceToOffsetTable<DiffVec> DiffSeqs(PI.getLanguage());
   SmallVector<DiffVec, 4> SubRegLists(Regs.size());
   SmallVector<DiffVec, 4> SuperRegLists(Regs.size());
   SmallVector<DiffVec, 4> RegUnitLists(Regs.size());
   SmallVector<unsigned, 4> RegUnitInitScale(Regs.size());
 
   // List of lane masks accompanying register unit sequences.
-  SequenceToOffsetTable<MaskVec> LaneMaskSeqs;
+  SequenceToOffsetTable<MaskVec> LaneMaskSeqs(PI.getLanguage());
   SmallVector<MaskVec, 4> RegUnitLaneMasks(Regs.size());
 
-  // Keep track of sub-register names as well. These are not differentially
-  // encoded.
-  typedef SmallVector<const CodeGenSubRegIndex*, 4> SubRegIdxVec;
-  SequenceToOffsetTable<SubRegIdxVec, deref<std::less<>>> SubRegIdxSeqs;
+  SequenceToOffsetTable<SubRegIdxVec, deref<std::less<>>> SubRegIdxSeqs(PI.getLanguage());
   SmallVector<SubRegIdxVec, 4> SubRegIdxLists(Regs.size());
 
-  SequenceToOffsetTable<std::string> RegStrings;
+  SequenceToOffsetTable<std::string> RegStrings(PI.getLanguage());
 
   // Precompute register lists for the SequenceToOffsetTable.
   unsigned i = 0;
   for (auto I = Regs.begin(), E = Regs.end(); I != E; ++I, ++i) {
     const auto &Reg = *I;
     RegStrings.add(std::string(Reg.getName()));
 
     // Compute the ordered sub-register list.
#endif
     LaneMaskSeqs.add(LaneMaskVec);
   }
 
   // Compute the final layout of the sequence table.
   DiffSeqs.layout();
   LaneMaskSeqs.layout();
   SubRegIdxSeqs.layout();
 
-  OS << "namespace llvm {\n\n";
+  PI.emitIncludeToggle("GET_REGINFO_MC_DESC", true);
+  PI.emitNamespace("llvm", true);
 
   const std::string &TargetName = std::string(Target.getName());
 
   // Emit the shared table of differential lists.
-  OS << "extern const MCPhysReg " << TargetName << "RegDiffLists[] = {\n";
-  DiffSeqs.emit(OS, printDiff16);
-  OS << "};\n\n";
+  PI.regInfoEmitRegDiffLists(TargetName, DiffSeqs);
 
   // Emit the shared table of regunit lane mask sequences.
-  OS << "extern const LaneBitmask " << TargetName << "LaneMaskLists[] = {\n";
-  LaneMaskSeqs.emit(OS, printMask, "LaneBitmask::getAll()");
-  OS << "};\n\n";
+  PI.regInfoEmitLaneMaskLists(TargetName, LaneMaskSeqs);
 
   // Emit the table of sub-register indexes.
-  OS << "extern const uint16_t " << TargetName << "SubRegIdxLists[] = {\n";
-  SubRegIdxSeqs.emit(OS, printSubRegIndex);
-  OS << "};\n\n";
+  PI.regInfoEmitSubRegIdxLists(TargetName, SubRegIdxSeqs);
 
   // Emit the table of sub-register index sizes.
-  OS << "extern const MCRegisterInfo::SubRegCoveredBits "
-     << TargetName << "SubRegIdxRanges[] = {\n";
-  OS << "  { " << (uint16_t)-1 << ", " << (uint16_t)-1 << " },\n";
-  for (const auto &Idx : SubRegIndices) {
-    OS << "  { " << Idx.Offset << ", " << Idx.Size << " },\t// "
-       << Idx.getName() << "\n";
-  }
-  OS << "};\n\n";
+  PI.regInfoEmitSubRegIdxSizes(TargetName, SubRegIndices);
 
   // Emit the string table.
   RegStrings.layout();
-  RegStrings.emitStringLiteralDef(OS, Twine("extern const char ") + TargetName +
-                                          "RegStrings[]");
-
-  OS << "extern const MCRegisterDesc " << TargetName
-     << "RegDesc[] = { // Descriptors\n";
-  OS << "  { " << RegStrings.get("") << ", 0, 0, 0, 0, 0 },\n";
+  PI.regInfoEmitSubRegStrTable(TargetName, RegStrings);
 
   // Emit the register descriptors now.
-  i = 0;
-  for (const auto &Reg : Regs) {
-    OS << "  { " << RegStrings.get(std::string(Reg.getName())) << ", "
-       << DiffSeqs.get(SubRegLists[i]) << ", " << DiffSeqs.get(SuperRegLists[i])
-       << ", " << SubRegIdxSeqs.get(SubRegIdxLists[i]) << ", "
-       << (DiffSeqs.get(RegUnitLists[i]) * 16 + RegUnitInitScale[i]) << ", "
-       << LaneMaskSeqs.get(RegUnitLaneMasks[i]) << " },\n";
-    ++i;
-  }
-  OS << "};\n\n";      // End of register descriptors...
+  PI.regInfoEmitRegDesc(LaneMaskSeqs,
+          Regs, SubRegIdxSeqs, DiffSeqs,
+          SubRegIdxLists, SubRegLists,
+          SuperRegLists, RegUnitLists,
+          RegUnitInitScale, RegUnitLaneMasks,
+          RegStrings);
 
   // Emit the table of register unit roots. Each regunit has one or two root
   // registers.
-  OS << "extern const MCPhysReg " << TargetName << "RegUnitRoots[][2] = {\n";
-  for (unsigned i = 0, e = RegBank.getNumNativeRegUnits(); i != e; ++i) {
-    ArrayRef<const CodeGenRegister*> Roots = RegBank.getRegUnit(i).getRoots();
-    assert(!Roots.empty() && "All regunits must have a root register.");
-    assert(Roots.size() <= 2 && "More than two roots not supported yet.");
-    OS << "  { ";
-    ListSeparator LS;
-    for (const CodeGenRegister *R : Roots)
-      OS << LS << getQualifiedName(R->TheDef);
-    OS << " },\n";
-  }
-  OS << "};\n\n";
+  PI.regInfoEmitRegUnitRoots(TargetName, RegBank);
 
   const auto &RegisterClasses = RegBank.getRegClasses();
 
   // Loop over all of the register classes... emitting each one.
-  OS << "namespace {     // Register classes...\n";
+  PI.emitNamespace("", true, "Register classes...");
 
-  SequenceToOffsetTable<std::string> RegClassStrings;
+  SequenceToOffsetTable<std::string> RegClassStrings(PI.getLanguage());
 
   // Emit the register enum value arrays for each RegisterClass
-  for (const auto &RC : RegisterClasses) {
-    ArrayRef<Record*> Order = RC.getOrder();
-
-    // Give the register class a legal C name if it's anonymous.
-    const std::string &Name = RC.getName();
-
-    RegClassStrings.add(Name);
-
-    // Emit the register list now (unless it would be a zero-length array).
-    if (!Order.empty()) {
-      OS << "  // " << Name << " Register Class...\n"
-         << "  const MCPhysReg " << Name << "[] = {\n    ";
-      for (Record *Reg : Order) {
-        OS << getQualifiedName(Reg) << ", ";
-      }
-      OS << "\n  };\n\n";
-
-      OS << "  // " << Name << " Bit set.\n"
-         << "  const uint8_t " << Name << "Bits[] = {\n    ";
-      BitVectorEmitter BVE;
-      for (Record *Reg : Order) {
-        BVE.add(Target.getRegBank().getReg(Reg)->EnumValue);
-      }
-      BVE.print(OS);
-      OS << "\n  };\n\n";
-    }
-  }
-  OS << "} // end anonymous namespace\n\n";
+  PI.regInfoEmitRegClasses(RegisterClasses, RegClassStrings, Target);
+  PI.emitNamespace("", false);
 
   RegClassStrings.layout();
-  RegClassStrings.emitStringLiteralDef(
-      OS, Twine("extern const char ") + TargetName + "RegClassStrings[]");
-
-  OS << "extern const MCRegisterClass " << TargetName
-     << "MCRegisterClasses[] = {\n";
-
-  for (const auto &RC : RegisterClasses) {
-    ArrayRef<Record *> Order = RC.getOrder();
-    std::string RCName = Order.empty() ? "nullptr" : RC.getName();
-    std::string RCBitsName = Order.empty() ? "nullptr" : RC.getName() + "Bits";
-    std::string RCBitsSize = Order.empty() ? "0" : "sizeof(" + RCBitsName + ")";
-    assert(isInt<8>(RC.CopyCost) && "Copy cost too large.");
-    uint32_t RegSize = 0;
-    if (RC.RSI.isSimple())
-      RegSize = RC.RSI.getSimple().RegSize;
-    OS << "  { " << RCName << ", " << RCBitsName << ", "
-       << RegClassStrings.get(RC.getName()) << ", " << RC.getOrder().size()
-       << ", " << RCBitsSize << ", " << RC.getQualifiedName() + "RegClassID"
-       << ", " << RegSize << ", " << RC.CopyCost << ", "
-       << (RC.Allocatable ? "true" : "false") << " },\n";
-  }
+  PI.regInfoEmitStrLiteralRegClasses(TargetName, RegClassStrings);
 
-  OS << "};\n\n";
+  PI.regInfoEmitMCRegClassesTable(TargetName, RegisterClasses, RegClassStrings);
 
-  EmitRegMappingTables(OS, Regs, false);
+  EmitRegMappingTables(Regs, false);
 
   // Emit Reg encoding table
-  OS << "extern const uint16_t " << TargetName;
-  OS << "RegEncodingTable[] = {\n";
-  // Add entry for NoRegister
-  OS << "  0,\n";
-  for (const auto &RE : Regs) {
-    Record *Reg = RE.TheDef;
-    BitsInit *BI = Reg->getValueAsBitsInit("HWEncoding");
-    uint64_t Value = 0;
-    for (unsigned b = 0, be = BI->getNumBits(); b != be; ++b) {
-      if (BitInit *B = dyn_cast<BitInit>(BI->getBit(b)))
-        Value |= (uint64_t)B->getValue() << b;
-    }
-    OS << "  " << Value << ",\n";
-  }
-  OS << "};\n";       // End of HW encoding table
+  PI.regInfoEmitRegEncodingTable(TargetName, Regs);
 
   // MCRegisterInfo initialization routine.
-  OS << "static inline void Init" << TargetName
-     << "MCRegisterInfo(MCRegisterInfo *RI, unsigned RA, "
-     << "unsigned DwarfFlavour = 0, unsigned EHFlavour = 0, unsigned PC = 0) "
-        "{\n"
-     << "  RI->InitMCRegisterInfo(" << TargetName << "RegDesc, "
-     << Regs.size() + 1 << ", RA, PC, " << TargetName << "MCRegisterClasses, "
-     << RegisterClasses.size() << ", " << TargetName << "RegUnitRoots, "
-     << RegBank.getNumNativeRegUnits() << ", " << TargetName << "RegDiffLists, "
-     << TargetName << "LaneMaskLists, " << TargetName << "RegStrings, "
-     << TargetName << "RegClassStrings, " << TargetName << "SubRegIdxLists, "
-     << (std::distance(SubRegIndices.begin(), SubRegIndices.end()) + 1) << ",\n"
-     << TargetName << "SubRegIdxRanges, " << TargetName
-     << "RegEncodingTable);\n\n";
-
-  EmitRegMapping(OS, Regs, false);
+  PI.regInfoEmitMCRegInfoInit(TargetName, RegBank, Regs, RegisterClasses, SubRegIndices);
 
-  OS << "}\n\n";
+  EmitRegMapping(Regs, false);
 
-  OS << "} // end namespace llvm\n\n";
-  OS << "#endif // GET_REGINFO_MC_DESC\n\n";
+  PI.emitNamespace("llvm", false);
+  PI.emitIncludeToggle("GET_REGINFO_MC_DESC", false);
 }
 
 void
-RegisterInfoEmitter::runTargetHeader(raw_ostream &OS, CodeGenTarget &Target,
+RegisterInfoEmitter::runTargetHeader(CodeGenTarget &Target,
                                      CodeGenRegBank &RegBank) {
-  emitSourceFileHeader("Register Information Header Fragment", OS);
-
-  OS << "\n#ifdef GET_REGINFO_HEADER\n";
-  OS << "#undef GET_REGINFO_HEADER\n\n";
+  PI.regInfoEmitSourceFileHeader("Register Information Header Fragment");
+  PI.emitIncludeToggle("GET_REGINFO_HEADER", true);
 
   const std::string &TargetName = std::string(Target.getName());
   std::string ClassName = TargetName + "GenRegisterInfo";
+  PI.regInfoEmitHeaderIncludes();
 
-  OS << "#include \"llvm/CodeGen/TargetRegisterInfo.h\"\n\n";
-
-  OS << "namespace llvm {\n\n";
-
-  OS << "class " << TargetName << "FrameLowering;\n\n";
-
-  OS << "struct " << ClassName << " : public TargetRegisterInfo {\n"
-     << "  explicit " << ClassName
-     << "(unsigned RA, unsigned D = 0, unsigned E = 0,\n"
-     << "      unsigned PC = 0, unsigned HwMode = 0);\n";
-  if (!RegBank.getSubRegIndices().empty()) {
-    OS << "  unsigned composeSubRegIndicesImpl"
-       << "(unsigned, unsigned) const override;\n"
-       << "  LaneBitmask composeSubRegIndexLaneMaskImpl"
-       << "(unsigned, LaneBitmask) const override;\n"
-       << "  LaneBitmask reverseComposeSubRegIndexLaneMaskImpl"
-       << "(unsigned, LaneBitmask) const override;\n"
-       << "  const TargetRegisterClass *getSubClassWithSubReg"
-       << "(const TargetRegisterClass *, unsigned) const override;\n"
-       << "  const TargetRegisterClass *getSubRegisterClass"
-       << "(const TargetRegisterClass *, unsigned) const override;\n";
-  }
-  OS << "  const RegClassWeight &getRegClassWeight("
-     << "const TargetRegisterClass *RC) const override;\n"
-     << "  unsigned getRegUnitWeight(unsigned RegUnit) const override;\n"
-     << "  unsigned getNumRegPressureSets() const override;\n"
-     << "  const char *getRegPressureSetName(unsigned Idx) const override;\n"
-     << "  unsigned getRegPressureSetLimit(const MachineFunction &MF, unsigned "
-        "Idx) const override;\n"
-     << "  const int *getRegClassPressureSets("
-     << "const TargetRegisterClass *RC) const override;\n"
-     << "  const int *getRegUnitPressureSets("
-     << "unsigned RegUnit) const override;\n"
-     << "  ArrayRef<const char *> getRegMaskNames() const override;\n"
-     << "  ArrayRef<const uint32_t *> getRegMasks() const override;\n"
-     << "  bool isGeneralPurposeRegister(const MachineFunction &, "
-     << "MCRegister) const override;\n"
-     << "  bool isFixedRegister(const MachineFunction &, "
-     << "MCRegister) const override;\n"
-     << "  bool isArgumentRegister(const MachineFunction &, "
-     << "MCRegister) const override;\n"
-     << "  bool isConstantPhysReg(MCRegister PhysReg) const override final;\n"
-     << "  /// Devirtualized TargetFrameLowering.\n"
-     << "  static const " << TargetName << "FrameLowering *getFrameLowering(\n"
-     << "      const MachineFunction &MF);\n";
-
+  PI.emitNamespace("llvm", true);
   const auto &RegisterClasses = RegBank.getRegClasses();
-  if (llvm::any_of(RegisterClasses, [](const auto &RC) { return RC.getBaseClassOrder(); })) {
-    OS << "  const TargetRegisterClass *getPhysRegBaseClass(MCRegister Reg) const override;\n";
-  }
-
-  OS << "};\n\n";
+  PI.regInfoEmitHeaderDecl(TargetName, ClassName, !RegBank.getSubRegIndices().empty(),
+    llvm::any_of(RegisterClasses, [](const auto &RC) { return RC.getBaseClassOrder(); }));
 
   if (!RegisterClasses.empty()) {
-    OS << "namespace " << RegisterClasses.front().Namespace
-       << " { // Register classes\n";
-
-    for (const auto &RC : RegisterClasses) {
-      const std::string &Name = RC.getName();
-
-      // Output the extern for the instance.
-      OS << "  extern const TargetRegisterClass " << Name << "RegClass;\n";
-    }
-    OS << "} // end namespace " << RegisterClasses.front().Namespace << "\n\n";
+    PI.emitNamespace(RegisterClasses.front().Namespace.str(), true, "Register classes");
+    PI.regInfoEmitHeaderExternRegClasses(RegisterClasses);
+    PI.emitNamespace(RegisterClasses.front().Namespace.str(), false);
   }
-  OS << "} // end namespace llvm\n\n";
-  OS << "#endif // GET_REGINFO_HEADER\n\n";
+  PI.emitNamespace("llvm", false);
+  PI.emitIncludeToggle("GET_REGINFO_HEADER", false);
 }
 
 //
 // runTargetDesc - Output the target register and register file descriptions.
 //
 void
-RegisterInfoEmitter::runTargetDesc(raw_ostream &OS, CodeGenTarget &Target,
+RegisterInfoEmitter::runTargetDesc(CodeGenTarget &Target,
                                    CodeGenRegBank &RegBank){
-  emitSourceFileHeader("Target Register and Register Classes Information", OS);
+  PI.regInfoEmitSourceFileHeader("Target Register and Register Classes Information");
 
-  OS << "\n#ifdef GET_REGINFO_TARGET_DESC\n";
-  OS << "#undef GET_REGINFO_TARGET_DESC\n\n";
-
-  OS << "namespace llvm {\n\n";
+  PI.emitIncludeToggle("GET_REGINFO_TARGET_DESC", true);
+  PI.emitNamespace("llvm", true);
 
   // Get access to MCRegisterClass data.
-  OS << "extern const MCRegisterClass " << Target.getName()
-     << "MCRegisterClasses[];\n";
+  PI.regInfoEmitExternRegClassesArr(Target.getName().str());
 
   // Start out by emitting each of the register classes.
   const auto &RegisterClasses = RegBank.getRegClasses();
   const auto &SubRegIndices = RegBank.getSubRegIndices();
 
   // Collect all registers belonging to any allocatable class.
   std::set<Record*> AllocatableRegs;
 
   // Collect allocatable registers.
   for (const auto &RC : RegisterClasses) {
     ArrayRef<Record*> Order = RC.getOrder();
 
     if (RC.Allocatable)
       AllocatableRegs.insert(Order.begin(), Order.end());
   }
 
   const CodeGenHwModes &CGH = Target.getHwModes();
   unsigned NumModes = CGH.getNumModeIds();
 
   // Build a shared array of value types.
-  SequenceToOffsetTable<std::vector<MVT::SimpleValueType>> VTSeqs;
+  SequenceToOffsetTable<std::vector<MVT::SimpleValueType>> VTSeqs(PI.getLanguage());
   for (unsigned M = 0; M < NumModes; ++M) {
     for (const auto &RC : RegisterClasses) {
       std::vector<MVT::SimpleValueType> S;
       for (const ValueTypeByHwMode &VVT : RC.VTs)
         S.push_back(VVT.get(M).SimpleTy);
       VTSeqs.add(S);
     }
   }
   VTSeqs.layout();
-  OS << "\nstatic const MVT::SimpleValueType VTLists[] = {\n";
-  VTSeqs.emit(OS, printSimpleValueType, "MVT::Other");
-  OS << "};\n";
+  PI.regInfoEmitVTSeqs(VTSeqs);
 
   // Emit SubRegIndex names, skipping 0.
-  OS << "\nstatic const char *SubRegIndexNameTable[] = { \"";
-
-  for (const auto &Idx : SubRegIndices) {
-    OS << Idx.getName();
-    OS << "\", \"";
-  }
-  OS << "\" };\n\n";
-
-  // Emit SubRegIndex lane masks, including 0.
-  OS << "\nstatic const LaneBitmask SubRegIndexLaneMaskTable[] = {\n  "
-        "LaneBitmask::getAll(),\n";
-  for (const auto &Idx : SubRegIndices) {
-    printMask(OS << "  ", Idx.LaneMask);
-    OS << ", // " << Idx.getName() << '\n';
-  }
-  OS << " };\n\n";
-
-  OS << "\n";
+  PI.regInfoEmitSubRegIdxTable(SubRegIndices);
 
   // Now that all of the structs have been emitted, emit the instances.
   if (!RegisterClasses.empty()) {
-    OS << "\nstatic const TargetRegisterInfo::RegClassInfo RegClassInfos[]"
-       << " = {\n";
-    for (unsigned M = 0; M < NumModes; ++M) {
-      unsigned EV = 0;
-      OS << "  // Mode = " << M << " (";
-      if (M == 0)
-        OS << "Default";
-      else
-        OS << CGH.getMode(M).Name;
-      OS << ")\n";
-      for (const auto &RC : RegisterClasses) {
-        assert(RC.EnumValue == EV && "Unexpected order of register classes");
-        ++EV;
-        (void)EV;
-        const RegSizeInfo &RI = RC.RSI.get(M);
-        OS << "  { " << RI.RegSize << ", " << RI.SpillSize << ", "
-           << RI.SpillAlignment;
-        std::vector<MVT::SimpleValueType> VTs;
-        for (const ValueTypeByHwMode &VVT : RC.VTs)
-          VTs.push_back(VVT.get(M).SimpleTy);
-        OS << ", VTLists+" << VTSeqs.get(VTs) << " },    // "
-           << RC.getName() << '\n';
-      }
-    }
-    OS << "};\n";
-
-
-    OS << "\nstatic const TargetRegisterClass *const "
-       << "NullRegClasses[] = { nullptr };\n\n";
+    PI.regInfoEmitRegClassInfoTable(RegisterClasses, VTSeqs, CGH, NumModes);
 
     // Emit register class bit mask tables. The first bit mask emitted for a
     // register class, RC, is the set of sub-classes, including RC itself.
     //
     // If RC has super-registers, also create a list of subreg indices and bit
     // masks, (Idx, Mask). The bit mask has a bit for every superreg regclass,
     // SuperRC, that satisfies:
     //
     //   For all SuperReg in SuperRC: SuperReg:Idx in RC
     //
     // The 0-terminated list of subreg indices starts at:
     //
     //   RC->getSuperRegIndices() = SuperRegIdxSeqs + ...
     //
     // The corresponding bitmasks follow the sub-class mask in memory. Each
     // mask has RCMaskWords uint32_t entries.
     //
     // Every bit mask present in the list has at least one bit set.
 
-    // Compress the sub-reg index lists.
-    typedef std::vector<const CodeGenSubRegIndex*> IdxList;
     SmallVector<IdxList, 8> SuperRegIdxLists(RegisterClasses.size());
-    SequenceToOffsetTable<IdxList, deref<std::less<>>> SuperRegIdxSeqs;
+    SequenceToOffsetTable<IdxList, deref<std::less<>>> SuperRegIdxSeqs(PI.getLanguage());
     BitVector MaskBV(RegisterClasses.size());
 
-    for (const auto &RC : RegisterClasses) {
-      OS << "static const uint32_t " << RC.getName()
-         << "SubClassMask[] = {\n  ";
-      printBitVectorAsHex(OS, RC.getSubClasses(), 32);
-
-      // Emit super-reg class masks for any relevant SubRegIndices that can
-      // project into RC.
-      IdxList &SRIList = SuperRegIdxLists[RC.EnumValue];
-      for (auto &Idx : SubRegIndices) {
-        MaskBV.reset();
-        RC.getSuperRegClasses(&Idx, MaskBV);
-        if (MaskBV.none())
-          continue;
-        SRIList.push_back(&Idx);
-        OS << "\n  ";
-        printBitVectorAsHex(OS, MaskBV, 32);
-        OS << "// " << Idx.getName();
-      }
-      SuperRegIdxSeqs.add(SRIList);
-      OS << "\n};\n\n";
-    }
+    PI.regInfoEmitSubClassMaskTable(RegisterClasses,
+                                    SuperRegIdxLists,
+                                    SuperRegIdxSeqs,
+                                    SubRegIndices,
+                                    MaskBV);
 
-    OS << "static const uint16_t SuperRegIdxSeqs[] = {\n";
     SuperRegIdxSeqs.layout();
-    SuperRegIdxSeqs.emit(OS, printSubRegIndex);
-    OS << "};\n\n";
+    PI.regInfoEmitSuperRegIdxSeqsTable(SuperRegIdxSeqs);
 
     // Emit NULL terminated super-class lists.
-    for (const auto &RC : RegisterClasses) {
-      ArrayRef<CodeGenRegisterClass*> Supers = RC.getSuperClasses();
-
-      // Skip classes without supers.  We can reuse NullRegClasses.
-      if (Supers.empty())
-        continue;
-
-      OS << "static const TargetRegisterClass *const "
-         << RC.getName() << "Superclasses[] = {\n";
-      for (const auto *Super : Supers)
-        OS << "  &" << Super->getQualifiedName() << "RegClass,\n";
-      OS << "  nullptr\n};\n\n";
-    }
+    PI.regInfoEmitSuperClassesTable(RegisterClasses);
 
     // Emit methods.
-    for (const auto &RC : RegisterClasses) {
-      if (!RC.AltOrderSelect.empty()) {
-        OS << "\nstatic inline unsigned " << RC.getName()
-           << "AltOrderSelect(const MachineFunction &MF) {"
-           << RC.AltOrderSelect << "}\n\n"
-           << "static ArrayRef<MCPhysReg> " << RC.getName()
-           << "GetRawAllocationOrder(const MachineFunction &MF) {\n";
-        for (unsigned oi = 1 , oe = RC.getNumOrders(); oi != oe; ++oi) {
-          ArrayRef<Record*> Elems = RC.getOrder(oi);
-          if (!Elems.empty()) {
-            OS << "  static const MCPhysReg AltOrder" << oi << "[] = {";
-            for (unsigned elem = 0; elem != Elems.size(); ++elem)
-              OS << (elem ? ", " : " ") << getQualifiedName(Elems[elem]);
-            OS << " };\n";
-          }
-        }
-        OS << "  const MCRegisterClass &MCR = " << Target.getName()
-           << "MCRegisterClasses[" << RC.getQualifiedName() + "RegClassID];\n"
-           << "  const ArrayRef<MCPhysReg> Order[] = {\n"
-           << "    makeArrayRef(MCR.begin(), MCR.getNumRegs()";
-        for (unsigned oi = 1, oe = RC.getNumOrders(); oi != oe; ++oi)
-          if (RC.getOrder(oi).empty())
-            OS << "),\n    ArrayRef<MCPhysReg>(";
-          else
-            OS << "),\n    makeArrayRef(AltOrder" << oi;
-        OS << ")\n  };\n  const unsigned Select = " << RC.getName()
-           << "AltOrderSelect(MF);\n  assert(Select < " << RC.getNumOrders()
-           << ");\n  return Order[Select];\n}\n";
-      }
-    }
+    PI.regInfoEmitRegClassMethods(RegisterClasses, Target.getName().str());
 
     // Now emit the actual value-initialized register class instances.
-    OS << "\nnamespace " << RegisterClasses.front().Namespace
-       << " {   // Register class instances\n";
+    PI.emitNamespace(RegisterClasses.front().Namespace.str(), true, "Register class instances");
+    PI.regInfomitRegClassInstances(RegisterClasses,
+                                   SuperRegIdxSeqs,
+                                   SuperRegIdxLists,
+                                   Target.getName().str());
+    PI.emitNamespace(RegisterClasses.front().Namespace.str(), false);
+  }
 
-    for (const auto &RC : RegisterClasses) {
-      OS << "  extern const TargetRegisterClass " << RC.getName()
-         << "RegClass = {\n    " << '&' << Target.getName()
-         << "MCRegisterClasses[" << RC.getName() << "RegClassID],\n    "
-         << RC.getName() << "SubClassMask,\n    SuperRegIdxSeqs + "
-         << SuperRegIdxSeqs.get(SuperRegIdxLists[RC.EnumValue]) << ",\n    ";
-      printMask(OS, RC.LaneMask);
-      OS << ",\n    " << (unsigned)RC.AllocationPriority << ",\n    "
-         << (RC.GlobalPriority ? "true" : "false") << ",\n    "
-         << format("0x%02x", RC.TSFlags) << ", /* TSFlags */\n    "
-         << (RC.HasDisjunctSubRegs ? "true" : "false")
-         << ", /* HasDisjunctSubRegs */\n    "
-         << (RC.CoveredBySubRegs ? "true" : "false")
-         << ", /* CoveredBySubRegs */\n    ";
-      if (RC.getSuperClasses().empty())
-        OS << "NullRegClasses,\n    ";
-      else
-        OS << RC.getName() << "Superclasses,\n    ";
-      if (RC.AltOrderSelect.empty())
-        OS << "nullptr\n";
-      else
-        OS << RC.getName() << "GetRawAllocationOrder\n";
-      OS << "  };\n\n";
-    }
-
-    OS << "} // end namespace " << RegisterClasses.front().Namespace << "\n";
-  }
-
-  OS << "\nnamespace {\n";
-  OS << "  const TargetRegisterClass *const RegisterClasses[] = {\n";
-  for (const auto &RC : RegisterClasses)
-    OS << "    &" << RC.getQualifiedName() << "RegClass,\n";
-  OS << "  };\n";
-  OS << "} // end anonymous namespace\n";
+  PI.emitNamespace("", true);
+  PI.regInfoEmitRegClassTable(RegisterClasses);
+  PI.emitNamespace("", false);
 
   // Emit extra information about registers.
   const std::string &TargetName = std::string(Target.getName());
   const auto &Regs = RegBank.getRegisters();
   unsigned NumRegCosts = 1;
   for (const auto &Reg : Regs)
     NumRegCosts = std::max((size_t)NumRegCosts, Reg.CostPerUse.size());
 
for (const auto &Reg : Regs) {
 
     if (AllocatableRegs.count(Reg.TheDef))
       InAllocClass.set(Reg.EnumValue);
   }
 
   // Emit the cost values as a 1D-array after grouping them by their indices,
   // i.e. the costs for all registers corresponds to index 0, 1, 2, etc.
   // Size of the emitted array should be NumRegCosts * (Regs.size() + 1).
-  OS << "\nstatic const uint8_t "
-     << "CostPerUseTable[] = { \n";
-  for (unsigned int I = 0; I < NumRegCosts; ++I) {
-    for (unsigned J = I, E = AllRegCostPerUse.size(); J < E; J += NumRegCosts)
-      OS << AllRegCostPerUse[J] << ", ";
-  }
-  OS << "};\n\n";
-
-  OS << "\nstatic const bool "
-     << "InAllocatableClassTable[] = { \n";
-  for (unsigned I = 0, E = InAllocClass.size(); I < E; ++I) {
-    OS << (InAllocClass[I] ? "true" : "false") << ", ";
-  }
-  OS << "};\n\n";
-
-  OS << "\nstatic const TargetRegisterInfoDesc " << TargetName
-     << "RegInfoDesc = { // Extra Descriptors\n";
-  OS << "CostPerUseTable, " << NumRegCosts << ", "
-     << "InAllocatableClassTable";
-  OS << "};\n\n"; // End of register descriptors...
+  PI.regInfoEmitCostPerUseTable(AllRegCostPerUse, NumRegCosts);
+  PI.regInfoEmitInAllocatableClassTable(InAllocClass);
+  PI.regInfoEmitRegExtraDesc(TargetName, NumRegCosts);
+  // End of register descriptors...
 
   std::string ClassName = Target.getName().str() + "GenRegisterInfo";
 
   auto SubRegIndicesSize =
       std::distance(SubRegIndices.begin(), SubRegIndices.end());
 
   if (!SubRegIndices.empty()) {
-    emitComposeSubRegIndices(OS, RegBank, ClassName);
-    emitComposeSubRegIndexLaneMask(OS, RegBank, ClassName);
+    emitComposeSubRegIndices(RegBank, ClassName);
+    emitComposeSubRegIndexLaneMask(RegBank, ClassName);
   }
 
   if (!SubRegIndices.empty()) {
-    // Emit getSubClassWithSubReg.
-    OS << "const TargetRegisterClass *" << ClassName
-       << "::getSubClassWithSubReg(const TargetRegisterClass *RC, unsigned Idx)"
-       << " const {\n";
-    // Use the smallest type that can hold a regclass ID with room for a
-    // sentinel.
-    if (RegisterClasses.size() <= UINT8_MAX)
-      OS << "  static const uint8_t Table[";
-    else if (RegisterClasses.size() <= UINT16_MAX)
-      OS << "  static const uint16_t Table[";
-    else
-      PrintFatalError("Too many register classes.");
-    OS << RegisterClasses.size() << "][" << SubRegIndicesSize << "] = {\n";
-    for (const auto &RC : RegisterClasses) {
-      OS << "    {\t// " << RC.getName() << "\n";
-      for (auto &Idx : SubRegIndices) {
-        if (CodeGenRegisterClass *SRC = RC.getSubClassWithSubReg(&Idx))
-          OS << "      " << SRC->EnumValue + 1 << ",\t// " << Idx.getName()
-             << " -> " << SRC->getName() << "\n";
-        else
-          OS << "      0,\t// " << Idx.getName() << "\n";
-      }
-      OS << "    },\n";
-    }
-    OS << "  };\n  assert(RC && \"Missing regclass\");\n"
-       << "  if (!Idx) return RC;\n  --Idx;\n"
-       << "  assert(Idx < " << SubRegIndicesSize << " && \"Bad subreg\");\n"
-       << "  unsigned TV = Table[RC->getID()][Idx];\n"
-       << "  return TV ? getRegClass(TV - 1) : nullptr;\n}\n\n";
-
-    // Emit getSubRegisterClass
-    OS << "const TargetRegisterClass *" << ClassName
-       << "::getSubRegisterClass(const TargetRegisterClass *RC, unsigned Idx)"
-       << " const {\n";
-
-    // Use the smallest type that can hold a regclass ID with room for a
-    // sentinel.
-    if (RegisterClasses.size() <= UINT8_MAX)
-      OS << "  static const uint8_t Table[";
-    else if (RegisterClasses.size() <= UINT16_MAX)
-      OS << "  static const uint16_t Table[";
-    else
-      PrintFatalError("Too many register classes.");
-
-    OS << RegisterClasses.size() << "][" << SubRegIndicesSize << "] = {\n";
-
-    for (const auto &RC : RegisterClasses) {
-      OS << "    {\t// " << RC.getName() << '\n';
-      for (auto &Idx : SubRegIndices) {
-        std::optional<std::pair<CodeGenRegisterClass *, CodeGenRegisterClass *>>
-            MatchingSubClass = RC.getMatchingSubClassWithSubRegs(RegBank, &Idx);
-
-        unsigned EnumValue = 0;
-        if (MatchingSubClass) {
-          CodeGenRegisterClass *SubRegClass = MatchingSubClass->second;
-          EnumValue = SubRegClass->EnumValue + 1;
-        }
-
-        OS << "      " << EnumValue << ",\t// "
-           << RC.getName() << ':' << Idx.getName();
-
-        if (MatchingSubClass) {
-          CodeGenRegisterClass *SubRegClass = MatchingSubClass->second;
-          OS << " -> " << SubRegClass->getName();
-        }
-
-        OS << '\n';
-      }
+    PI.regInfoEmitSubClassSubRegGetter(ClassName,
+                                       SubRegIndicesSize,
+                                       SubRegIndices,
+                                       RegisterClasses,
+                                       RegBank);
 
-      OS << "    },\n";
-    }
-    OS << "  };\n  assert(RC && \"Missing regclass\");\n"
-       << "  if (!Idx) return RC;\n  --Idx;\n"
-       << "  assert(Idx < " << SubRegIndicesSize << " && \"Bad subreg\");\n"
-       << "  unsigned TV = Table[RC->getID()][Idx];\n"
-       << "  return TV ? getRegClass(TV - 1) : nullptr;\n}\n\n";
-  }
-
-  EmitRegUnitPressure(OS, RegBank, ClassName);
+  EmitRegUnitPressure(RegBank, ClassName);
 
   // Emit register base class mapper
   if (!RegisterClasses.empty()) {
     // Collect base classes
     SmallVector<const CodeGenRegisterClass*> BaseClasses;
     for (const auto &RC : RegisterClasses) {
       if (RC.getBaseClassOrder())
         BaseClasses.push_back(&RC);
if (!BaseClasses.empty()) {
 
       // Build mapping for Regs (+1 for NoRegister)
       std::vector<uint8_t> Mapping(Regs.size() + 1, 0);
       for (int RCIdx = BaseClasses.size() - 1; RCIdx >= 0; --RCIdx) {
         for (const auto Reg : BaseClasses[RCIdx]->getMembers())
           Mapping[Reg->EnumValue] = RCIdx + 1;
       }
 
-      OS << "\n// Register to base register class mapping\n\n";
-      OS << "\n";
-      OS << "const TargetRegisterClass *" << ClassName
-         << "::getPhysRegBaseClass(MCRegister Reg)"
-         << " const {\n";
-      OS << "  static const TargetRegisterClass *BaseClasses[" << (BaseClasses.size() + 1) << "] = {\n";
-      OS << "    nullptr,\n";
-      for (const auto RC : BaseClasses)
-        OS << "    &" << RC->getQualifiedName() << "RegClass,\n";
-      OS << "  };\n";
-      OS << "  static const uint8_t Mapping[" << Mapping.size() << "] = {\n    ";
-      for (const uint8_t Value : Mapping)
-        OS << (unsigned)Value << ",";
-      OS << "  };\n\n";
-      OS << "  assert(Reg < sizeof(Mapping));\n";
-      OS << "  return BaseClasses[Mapping[Reg]];\n";
-      OS << "}\n";
+      PI.regInfoEmitRegBaseClassMapping(ClassName, BaseClasses, Mapping);
     }
   }
 
   // Emit the constructor of the class...
-  OS << "extern const MCRegisterDesc " << TargetName << "RegDesc[];\n";
-  OS << "extern const MCPhysReg " << TargetName << "RegDiffLists[];\n";
-  OS << "extern const LaneBitmask " << TargetName << "LaneMaskLists[];\n";
-  OS << "extern const char " << TargetName << "RegStrings[];\n";
-  OS << "extern const char " << TargetName << "RegClassStrings[];\n";
-  OS << "extern const MCPhysReg " << TargetName << "RegUnitRoots[][2];\n";
-  OS << "extern const uint16_t " << TargetName << "SubRegIdxLists[];\n";
-  OS << "extern const MCRegisterInfo::SubRegCoveredBits "
-     << TargetName << "SubRegIdxRanges[];\n";
-  OS << "extern const uint16_t " << TargetName << "RegEncodingTable[];\n";
-
-  EmitRegMappingTables(OS, Regs, true);
-
-  OS << ClassName << "::\n"
-     << ClassName
-     << "(unsigned RA, unsigned DwarfFlavour, unsigned EHFlavour,\n"
-        "      unsigned PC, unsigned HwMode)\n"
-     << "  : TargetRegisterInfo(&" << TargetName << "RegInfoDesc"
-     << ", RegisterClasses, RegisterClasses+" << RegisterClasses.size() << ",\n"
-     << "             SubRegIndexNameTable, SubRegIndexLaneMaskTable,\n"
-     << "             ";
-  printMask(OS, RegBank.CoveringLanes);
-  OS << ", RegClassInfos, HwMode) {\n"
-     << "  InitMCRegisterInfo(" << TargetName << "RegDesc, " << Regs.size() + 1
-     << ", RA, PC,\n                     " << TargetName
-     << "MCRegisterClasses, " << RegisterClasses.size() << ",\n"
-     << "                     " << TargetName << "RegUnitRoots,\n"
-     << "                     " << RegBank.getNumNativeRegUnits() << ",\n"
-     << "                     " << TargetName << "RegDiffLists,\n"
-     << "                     " << TargetName << "LaneMaskLists,\n"
-     << "                     " << TargetName << "RegStrings,\n"
-     << "                     " << TargetName << "RegClassStrings,\n"
-     << "                     " << TargetName << "SubRegIdxLists,\n"
-     << "                     " << SubRegIndicesSize + 1 << ",\n"
-     << "                     " << TargetName << "SubRegIdxRanges,\n"
-     << "                     " << TargetName << "RegEncodingTable);\n\n";
+  PI.regInfoEmitExternTableDecl(TargetName);
+
+  EmitRegMappingTables(Regs, true);
 
-  EmitRegMapping(OS, Regs, true);
+  PI.regInfoEmitRegClassInit(TargetName,
+                             ClassName,
+                             RegBank,
+                             RegisterClasses,
+                             Regs,
+                             SubRegIndicesSize);
 
-  OS << "}\n\n";
+  EmitRegMapping(Regs, true);
 
   // Emit CalleeSavedRegs information.
   std::vector<Record*> CSRSets =
     Records.getAllDerivedDefinitions("CalleeSavedRegs");
   for (unsigned i = 0, e = CSRSets.size(); i != e; ++i) {
     Record *CSRSet = CSRSets[i];
     const SetTheory::RecVec *Regs = RegBank.getSets().expand(CSRSet);
     assert(Regs && "Cannot expand CalleeSavedRegs instance");
 
     // Emit the *_SaveList list of callee-saved registers.
-    OS << "static const MCPhysReg " << CSRSet->getName()
-       << "_SaveList[] = { ";
-    for (unsigned r = 0, re = Regs->size(); r != re; ++r)
-      OS << getQualifiedName((*Regs)[r]) << ", ";
-    OS << "0 };\n";
+    PI.regInfoEmitSaveListTable(CSRSet, Regs);
 
     // Emit the *_RegMask bit mask of call-preserved registers.
     BitVector Covered = RegBank.computeCoveredRegisters(*Regs);
 
     // Check for an optional OtherPreserved set.
     // Add those registers to RegMask, but not to SaveList.
     if (DagInit *OPDag =
         dyn_cast<DagInit>(CSRSet->getValueInit("OtherPreserved"))) {
       SetTheory::RecSet OPSet;
       RegBank.getSets().evaluate(OPDag, OPSet, CSRSet->getLoc());
       Covered |= RegBank.computeCoveredRegisters(
         ArrayRef<Record*>(OPSet.begin(), OPSet.end()));
     }
 
     // Add all constant physical registers to the preserved mask:
     SetTheory::RecSet ConstantSet;
     for (auto &Reg : RegBank.getRegisters()) {
       if (Reg.Constant)
         ConstantSet.insert(Reg.TheDef);
     }
     Covered |= RegBank.computeCoveredRegisters(
         ArrayRef<Record *>(ConstantSet.begin(), ConstantSet.end()));
 
-    OS << "static const uint32_t " << CSRSet->getName()
-       << "_RegMask[] = { ";
-    printBitVectorAsHex(OS, Covered, 32);
-    OS << "};\n";
-  }
-  OS << "\n\n";
-
-  OS << "ArrayRef<const uint32_t *> " << ClassName
-     << "::getRegMasks() const {\n";
-  if (!CSRSets.empty()) {
-    OS << "  static const uint32_t *const Masks[] = {\n";
-    for (Record *CSRSet : CSRSets)
-      OS << "    " << CSRSet->getName() << "_RegMask,\n";
-    OS << "  };\n";
-    OS << "  return makeArrayRef(Masks);\n";
-  } else {
-    OS << "  return std::nullopt;\n";
+    PI.regInfoEmitRegMaskTable(CSRSet->getName().str(), Covered);
   }
-  OS << "}\n\n";
+  PI.emitNewline(2);
+  PI.regInfoEmitGetRegMasks(CSRSets, ClassName);
 
   const std::list<CodeGenRegisterCategory> &RegCategories =
       RegBank.getRegCategories();
-  OS << "bool " << ClassName << "::\n"
-     << "isGeneralPurposeRegister(const MachineFunction &MF, "
-     << "MCRegister PhysReg) const {\n"
-     << "  return\n";
-  for (const CodeGenRegisterCategory &Category : RegCategories)
-    if (Category.getName() == "GeneralPurposeRegisters") {
-      for (const CodeGenRegisterClass *RC : Category.getClasses())
-        OS << "      " << RC->getQualifiedName()
-           << "RegClass.contains(PhysReg) ||\n";
-      break;
-    }
-  OS << "      false;\n";
-  OS << "}\n\n";
+  PI.regInfoEmitGPRCheck(ClassName, RegCategories);
+  PI.regInfoEmitFixedRegCheck(ClassName, RegCategories);
+  PI.regInfoEmitArgRegCheck(ClassName, RegCategories);
 
-  OS << "bool " << ClassName << "::\n"
-     << "isFixedRegister(const MachineFunction &MF, "
-     << "MCRegister PhysReg) const {\n"
-     << "  return\n";
-  for (const CodeGenRegisterCategory &Category : RegCategories)
-    if (Category.getName() == "FixedRegisters") {
-      for (const CodeGenRegisterClass *RC : Category.getClasses())
-        OS << "      " << RC->getQualifiedName()
-           << "RegClass.contains(PhysReg) ||\n";
-      break;
-    }
-  OS << "      false;\n";
-  OS << "}\n\n";
+  PI.regInfoEmitIsConstantPhysReg(Regs, ClassName);
+  PI.regInfoEmitGetRegMaskNames(CSRSets, ClassName);
 
-  OS << "bool " << ClassName << "::\n"
-     << "isArgumentRegister(const MachineFunction &MF, "
-     << "MCRegister PhysReg) const {\n"
-     << "  return\n";
-  for (const CodeGenRegisterCategory &Category : RegCategories)
-    if (Category.getName() == "ArgumentRegisters") {
-      for (const CodeGenRegisterClass *RC : Category.getClasses())
-        OS << "      " << RC->getQualifiedName()
-           << "RegClass.contains(PhysReg) ||\n";
-      break;
-    }
-  OS << "      false;\n";
-  OS << "}\n\n";
-
-  OS << "bool " << ClassName << "::\n"
-     << "isConstantPhysReg(MCRegister PhysReg) const {\n"
-     << "  return\n";
-  for (const auto &Reg : Regs)
-    if (Reg.Constant)
-      OS << "      PhysReg == " << getQualifiedName(Reg.TheDef) << " ||\n";
-  OS << "      false;\n";
-  OS << "}\n\n";
-
-  OS << "ArrayRef<const char *> " << ClassName
-     << "::getRegMaskNames() const {\n";
-  if (!CSRSets.empty()) {
-    OS << "  static const char *Names[] = {\n";
-    for (Record *CSRSet : CSRSets)
-      OS << "    " << '"' << CSRSet->getName() << '"' << ",\n";
-    OS << "  };\n";
-    OS << "  return makeArrayRef(Names);\n";
-  } else {
-    OS << "  return std::nullopt;\n";
-  }
-  OS << "}\n\n";
-
-  OS << "const " << TargetName << "FrameLowering *\n" << TargetName
-     << "GenRegisterInfo::getFrameLowering(const MachineFunction &MF) {\n"
-     << "  return static_cast<const " << TargetName << "FrameLowering *>(\n"
-     << "      MF.getSubtarget().getFrameLowering());\n"
-     << "}\n\n";
+  PI.regInfoEmitGetFrameLowering(TargetName);
 
-  OS << "} // end namespace llvm\n\n";
-  OS << "#endif // GET_REGINFO_TARGET_DESC\n\n";
+  PI.emitNamespace("llvm", false);
+  PI.emitIncludeToggle("GET_REGINFO_TARGET_DESC", false);
 }
 
-void RegisterInfoEmitter::run(raw_ostream &OS) {
+void RegisterInfoEmitter::run() {
   CodeGenRegBank &RegBank = Target.getRegBank();
   Records.startTimer("Print enums");
-  runEnums(OS, Target, RegBank);
+
+  PI.regInfoEmitSourceFileHeader("Target Register Enum Values");
+  PI.regInfoEmitEnums(Target, RegBank);
 
   Records.startTimer("Print MC registers");
-  runMCDesc(OS, Target, RegBank);
+  runMCDesc(Target, RegBank);
 
   Records.startTimer("Print header fragment");
-  runTargetHeader(OS, Target, RegBank);
+  runTargetHeader(Target, RegBank);
 
   Records.startTimer("Print target registers");
-  runTargetDesc(OS, Target, RegBank);
+  runTargetDesc(Target, RegBank);
 
   if (RegisterInfoDebug)
     debugDump(errs());
 }
 
-void RegisterInfoEmitter::debugDump(raw_ostream &OS) {
+void RegisterInfoEmitter::debugDump(raw_ostream &ErrOS) {
   CodeGenRegBank &RegBank = Target.getRegBank();
   const CodeGenHwModes &CGH = Target.getHwModes();
   unsigned NumModes = CGH.getNumModeIds();
   auto getModeName = [CGH] (unsigned M) -> StringRef {
     if (M == 0)
       return "Default";
     return CGH.getMode(M).Name;
   };
 
   for (const CodeGenRegisterClass &RC : RegBank.getRegClasses()) {
-    OS << "RegisterClass " << RC.getName() << ":\n";
-    OS << "\tSpillSize: {";
+    ErrOS << "RegisterClass " << RC.getName() << ":\n";
+    ErrOS << "\tSpillSize: {";
     for (unsigned M = 0; M != NumModes; ++M)
-      OS << ' ' << getModeName(M) << ':' << RC.RSI.get(M).SpillSize;
-    OS << " }\n\tSpillAlignment: {";
+      ErrOS << ' ' << getModeName(M) << ':' << RC.RSI.get(M).SpillSize;
+    ErrOS << " }\n\tSpillAlignment: {";
     for (unsigned M = 0; M != NumModes; ++M)
-      OS << ' ' << getModeName(M) << ':' << RC.RSI.get(M).SpillAlignment;
-    OS << " }\n\tNumRegs: " << RC.getMembers().size() << '\n';
-    OS << "\tLaneMask: " << PrintLaneMask(RC.LaneMask) << '\n';
-    OS << "\tHasDisjunctSubRegs: " << RC.HasDisjunctSubRegs << '\n';
-    OS << "\tCoveredBySubRegs: " << RC.CoveredBySubRegs << '\n';
-    OS << "\tAllocatable: " << RC.Allocatable << '\n';
-    OS << "\tAllocationPriority: " << unsigned(RC.AllocationPriority) << '\n';
-    OS << "\tRegs:";
+      ErrOS << ' ' << getModeName(M) << ':' << RC.RSI.get(M).SpillAlignment;
+    ErrOS << " }\n\tNumRegs: " << RC.getMembers().size() << '\n';
+    ErrOS << "\tLaneMask: " << PrintLaneMask(RC.LaneMask) << '\n';
+    ErrOS << "\tHasDisjunctSubRegs: " << RC.HasDisjunctSubRegs << '\n';
+    ErrOS << "\tCoveredBySubRegs: " << RC.CoveredBySubRegs << '\n';
+    ErrOS << "\tAllocatable: " << RC.Allocatable << '\n';
+    ErrOS << "\tAllocationPriority: " << unsigned(RC.AllocationPriority) << '\n';
+    ErrOS << "\tRegs:";
     for (const CodeGenRegister *R : RC.getMembers()) {
-      OS << " " << R->getName();
+      ErrOS << " " << R->getName();
     }
-    OS << '\n';
-    OS << "\tSubClasses:";
+    ErrOS << '\n';
+    ErrOS << "\tSubClasses:";
     const BitVector &SubClasses = RC.getSubClasses();
     for (const CodeGenRegisterClass &SRC : RegBank.getRegClasses()) {
       if (!SubClasses.test(SRC.EnumValue))
         continue;
-      OS << " " << SRC.getName();
+      ErrOS << " " << SRC.getName();
     }
-    OS << '\n';
-    OS << "\tSuperClasses:";
+    ErrOS << '\n';
+    ErrOS << "\tSuperClasses:";
     for (const CodeGenRegisterClass *SRC : RC.getSuperClasses()) {
-      OS << " " << SRC->getName();
+      ErrOS << " " << SRC->getName();
     }
-    OS << '\n';
+    ErrOS << '\n';
   }
 
   for (const CodeGenSubRegIndex &SRI : RegBank.getSubRegIndices()) {
-    OS << "SubRegIndex " << SRI.getName() << ":\n";
-    OS << "\tLaneMask: " << PrintLaneMask(SRI.LaneMask) << '\n';
-    OS << "\tAllSuperRegsCovered: " << SRI.AllSuperRegsCovered << '\n';
-    OS << "\tOffset, Size: " << SRI.Offset << ", " << SRI.Size << '\n';
+    ErrOS << "SubRegIndex " << SRI.getName() << ":\n";
+    ErrOS << "\tLaneMask: " << PrintLaneMask(SRI.LaneMask) << '\n';
+    ErrOS << "\tAllSuperRegsCovered: " << SRI.AllSuperRegsCovered << '\n';
+    ErrOS << "\tOffset, Size: " << SRI.Offset << ", " << SRI.Size << '\n';
   }
 
   for (const CodeGenRegister &R : RegBank.getRegisters()) {
-    OS << "Register " << R.getName() << ":\n";
-    OS << "\tCostPerUse: ";
+    ErrOS << "Register " << R.getName() << ":\n";
+    ErrOS << "\tCostPerUse: ";
     for (const auto &Cost : R.CostPerUse)
-      OS << Cost << " ";
-    OS << '\n';
-    OS << "\tCoveredBySubregs: " << R.CoveredBySubRegs << '\n';
-    OS << "\tHasDisjunctSubRegs: " << R.HasDisjunctSubRegs << '\n';
+      ErrOS << Cost << " ";
+    ErrOS << '\n';
+    ErrOS << "\tCoveredBySubregs: " << R.CoveredBySubRegs << '\n';
+    ErrOS << "\tHasDisjunctSubRegs: " << R.HasDisjunctSubRegs << '\n';
     for (std::pair<CodeGenSubRegIndex*,CodeGenRegister*> P : R.getSubRegs()) {
-      OS << "\tSubReg " << P.first->getName()
+      ErrOS << "\tSubReg " << P.first->getName()
          << " = " << P.second->getName() << '\n';
     }
   }
 }
 
 namespace llvm {
 
 void EmitRegisterInfo(RecordKeeper &RK, raw_ostream &OS) {
-  RegisterInfoEmitter(RK).run(OS);
+  formatted_raw_ostream FOS(OS);
+  PrinterLanguage const PLang = PrinterLLVM::getLanguage();
+  PrinterLLVM *PI = nullptr;
+  switch (PLang) {
+  default:
+    PrintFatalNote(
+        "RegisterInfo backend does not support the selected ouput language.");
+    return;
+  case PRINTER_LANG_CPP:
+    PI = new PrinterLLVM(FOS);
+    break;
+  }
+  RegisterInfoEmitter(RK, *PI).run();
+  delete PI;
 }
 
 } // end namespace llvm

llvm/utils/TableGen/RegisterInfoEmitterTypes.h

+//===- RegisterInfoEmitterTypes.h - Register Emitter Types -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===-----------------------------------------------------------------===//
+
+#ifndef LLVM_UTILS_TABLEGEN_REGISTERINFOEMITTERTYPES_H
+#define LLVM_UTILS_TABLEGEN_REGISTERINFOEMITTERTYPES_H
+
+#include "CodeGenRegisters.h"
+#include "CodeGenTarget.h"
+#include "SequenceToOffsetTable.h"
+#include "Types.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SparseBitVector.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/MachineValueType.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/TableGen/Error.h"
+#include "llvm/TableGen/Record.h"
+#include "llvm/TableGen/SetTheory.h"
+#include "llvm/TableGen/TableGenBackend.h"
+#include <algorithm>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <deque>
+#include <iterator>
+#include <set>
+#include <string>
+#include <vector>
+
+using namespace llvm;
+
+// Compress the sub-reg index lists.
+typedef std::vector<const CodeGenSubRegIndex *> IdxList;
+
+// Keep track of sub-register names as well. These are not differentially
+// encoded.
+typedef SmallVector<const CodeGenSubRegIndex *, 4> SubRegIdxVec;
+
+// Differentially encoded register and regunit lists allow for better
+// compression on regular register banks. The sequence is computed from the
+// differential list as:
+//
+//   out[0] = InitVal;
+//   out[n+1] = out[n] + diff[n]; // n = 0, 1, ...
+//
+// The initial value depends on the specific list. The list is terminated by a
+// 0 differential which means we can't encode repeated elements.
+typedef SmallVector<uint16_t, 4> DiffVec;
+typedef SmallVector<LaneBitmask, 4> MaskVec;
+
+// The lists of sub-registers and super-registers go in the same array.  That
+// allows us to share suffixes.
+typedef std::vector<const CodeGenRegister *> RegVec;
+
+using DwarfRegNumsMapPair = std::pair<Record*, std::vector<int64_t>>;
+using DwarfRegNumsVecTy = std::vector<DwarfRegNumsMapPair>;
+
+#endif // LLVM_UTILS_TABLEGEN_REGISTERINFOEMITTERTYPES_H

llvm/utils/TableGen/SequenceToOffsetTable.h

 // sequences as one big array.  Use the same memory when a sequence is a suffix
 // of another.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_UTILS_TABLEGEN_SEQUENCETOOFFSETTABLE_H
 #define LLVM_UTILS_TABLEGEN_SEQUENCETOOFFSETTABLE_H
 
+#include "PrinterTypes.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
 #include <cctype>
 #include <functional>
 #include <map>
 
class SequenceToOffsetTable {
   typedef std::map<SeqT, unsigned, SeqLess> SeqMap;
 
   // Sequences added so far, with suffixes removed.
   SeqMap Seqs;
 
   // Entries in the final table, or 0 before layout was called.
   unsigned Entries;
 
+  // The output language of the table.
+  PrinterLanguage PL;
+
   // isSuffix - Returns true if A is a suffix of B.
   static bool isSuffix(const SeqT &A, const SeqT &B) {
     return A.size() <= B.size() && std::equal(A.rbegin(), A.rend(), B.rbegin());
   }
 
 public:
-  SequenceToOffsetTable() : Entries(0) {}
+  SequenceToOffsetTable() : Entries(0), PL(PRINTER_LANG_CPP) {}
+  SequenceToOffsetTable(PrinterLanguage PL) : Entries(0), PL(PL) {}
 
   /// add - Add a sequence to the table.
   /// This must be called before layout().
   void add(const SeqT &Seq) {
     assert(Entries == 0 && "Cannot call add() after layout()");
     typename SeqMap::iterator I = Seqs.lower_bound(Seq);
 
     // If SeqMap contains a sequence that has Seq as a suffix, I will be
public:
   unsigned get(const SeqT &Seq) const {
     assert(Entries && "Call layout() before get()");
     typename SeqMap::const_iterator I = Seqs.lower_bound(Seq);
     assert(I != Seqs.end() && isSuffix(Seq, I->first) &&
            "get() called with sequence that wasn't added first");
     return I->second + (I->first.size() - Seq.size());
   }
 
+  void emitStringLiteralDef(raw_ostream &OS, const llvm::Twine &Decl) const {
+    switch (PL) {
+    default:
+      llvm_unreachable("Language not specified to print table in.");
+    case PRINTER_LANG_CPP:
+      emitStringLiteralDefCPP(OS, Decl);
+    }
+  }
+
+  void emit(raw_ostream &OS,
+            void (*Print)(raw_ostream&, ElemT),
+            const char *Term = "0") const {
+    switch (PL) {
+    default:
+      llvm_unreachable("Language not specified to print table in.");
+    case PRINTER_LANG_CPP:
+      emitCPP(OS, Print, Term);
+    }
+  }
+
   /// `emitStringLiteralDef` - Print out the table as the body of an array
   /// initializer, where each element is a C string literal terminated by
   /// `\0`. Falls back to emitting a comma-separated integer list if
   /// `EmitLongStrLiterals` is false
-  void emitStringLiteralDef(raw_ostream &OS, const llvm::Twine &Decl) const {
+  void emitStringLiteralDefCPP(raw_ostream &OS, const llvm::Twine &Decl) const {
     assert(Entries && "Call layout() before emitStringLiteralDef()");
     if (!EmitLongStrLiterals) {
       OS << Decl << " = {\n";
       emit(OS, printChar, "0");
       OS << "  0\n};\n\n";
       return;
     }
 
void emitStringLiteralDefCPP(raw_ostream &OS, const llvm::Twine &Decl) const {
     OS << "};\n"
        << "#ifdef __GNUC__\n"
        << "#pragma GCC diagnostic pop\n"
        << "#endif\n\n";
   }
 
   /// emit - Print out the table as the body of an array initializer.
   /// Use the Print function to print elements.
-  void emit(raw_ostream &OS,
+  void emitCPP(raw_ostream &OS,
             void (*Print)(raw_ostream&, ElemT),
-            const char *Term = "0") const {
+            const char *Term) const {
     assert((empty() || Entries) && "Call layout() before emit()");
     for (typename SeqMap::const_iterator I = Seqs.begin(), E = Seqs.end();
          I != E; ++I) {
       OS << "  /* " << I->second << " */ ";
       for (typename SeqT::const_iterator SI = I->first.begin(),
              SE = I->first.end(); SI != SE; ++SI) {
         Print(OS, *SI);
         OS << ", ";