[mlir][ods] AttrOrTypeGen uses Class

[Mogball]

Summary

AttrOrType def generator uses Class code gen helper,
instead of naked raw_ostream.

Depends on D113714 and D114807

[rriddle]

mlir/include/mlir/TableGen/Class.h

238–245

I'm getting a slight code smell here that we are slowly building towards a full C++ specification API.

468

Prefer accepting const Twine & instead of std::string. It accepts many more parameter types (e.g. StringRef, std::string, llvm::formatv, etc.), and can easily be converted to string.

543–544

Not sure this comment is true given that we have isPublic below.

552

Missing comment here?

557

nit: Drop the const, we don't generally add them.

Also please document these fields.

700

This needs some documentation.

mlir/include/mlir/TableGen/Format.h

54

nit: I'd use ArrayRef here instead.

mlir/lib/TableGen/AttrOrTypeDef.cpp

115–116

Can we just put the vector on the class and return ArrayRef instead?

mlir/lib/TableGen/Class.cpp

362–371

This needs some documentation.

mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp

161

[Mogball]

mlir/include/mlir/TableGen/Class.h

238–245

I agree. I'm not necessarily happy about it, but it absolutely is more maintainable than writing to a naked raw_ostream.

468

Good point, but what's your opinion on the stringify function I added? I wanted to elide copying std::string when it's passed in directly, and I've had some issues with const Twine &; for example,

void one(const Twine &value = "");
void one(bool value = false);

Confusingly, one("C string") calls one(bool)

[Mogball]

Review comments, and also adding more documentation.

[rriddle]

mlir/include/mlir/TableGen/Class.h

423

LLVM should have functionality for this: https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/ADT/BitmaskEnum.h

468

Which methods do we have that takes bool or Twine? If it isn't a lot of methods, we can always just add an overload specialized for const char */StringRef.

but what's your opinion on the stringify function I added?

It's giving me an off feeling, but that may be that we generally try not to use std::string directly.

mlir/lib/TableGen/Class.cpp

203–205

AFAIR we rely on the compiler to warn/error about missing cases.

301–302

Please switch this to an if/else to make it easier to read.

313

Please use proper foreach loops for these, the llvm::for_each doesn't add much.

mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp

211–216

I'd just use a proper foreach loop here, using llvm::for_each doesn't really add much.

431

semi unrelated, but the name "reindent" is throwing me off. It doesn't read like something that is emitted to the stream, I keep expecting it to return a reindented string. Can we rename that to something better?

462–463

?

511–515

raw_string_ostream would likely be cleaner here.

627

Drop the consts, we don't really add them unless really necessary (i.e. if they add value).

mlir/tools/mlir-tblgen/OpClass.h

26

Can you document what this does? The doc on the other finalize was quite nice.

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

754

Same comment about () here and elsewhere.

852

Can we drop the ()?

875–876

Can we drop the ()? We generally don't wrap unless necessary.

1950–1953

Is this right, AFAICT Method::Declaration & declaration is always false.

[rriddle]

mlir/include/mlir/TableGen/Class.h

423

Why is this defined outside of the namespace?

[Mogball]

mlir/include/mlir/TableGen/Class.h

468

I went for the stringify route because occasionally in ODS we create std::string and maybe something takes ownership of it. I got tired of debugging segmentation faults because .str() wasn't being called somewhere and a StringRef or Twine or format object was outliving its value.

[Mogball]

Review comments.

mlir/include/mlir/TableGen/Class.h

423

I didn't know about this! But also, it doesn't seem to work because the functions need to be constexpr (and there are asserts in them...)

mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp

431

I agree. I initially thought the same.

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

1950–1953

This actually expands to declaration ? Method::Declaration : Method::None. If that's not intuitive, I can remove it.

[rriddle]

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

1950–1953

Are you implying Method::Declaration & declaration is the same as declaration ? Method::Declaration : Method::None?

https://godbolt.org/z/rnjhbe77G

[rriddle]

mlir/include/mlir/TableGen/Class.h

436–439

Please remove this, the code that this creates is not readable.

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

1950–1953

I see now, you've defined a custom operator& for that. Please remove that, it creates a hacky difference in behavior that is not what someone what naturally expect.

[rriddle]

mlir/include/mlir/TableGen/Class.h

436–439

In general, please avoid overloading operators like this. It creates code that is difficult to read/maintain just for the sake of saving a line or two. Prefer writing clean/readable code over "tricky" code.

[Mogball]

mlir/include/mlir/TableGen/Class.h

436–439

Very well.

FYI I originally contemplated:

props |= Method::Static & ~(isStatic - 1u)

And so I thought that this would be "more readable" than that...

[Mogball]

Review comments and fixing build (hopefully)

[Mogball]

Fixing build .-.

[jpienaar]

llvm/include/llvm/ADT/STLExtras.h

1017

Sorry haven't gotten to this review yet. Could we perhaps extract out the changes to ADT into parent change for separate review?

[Mogball]

llvm/include/llvm/ADT/STLExtras.h

1017

Sure thing

[Mogball]

Splitting out changes to STLExtras.h

[rriddle]

LGTM, I think we can just land this and iterate from there.

llvm/include/llvm/ADT/STLExtras.h

 /// based for loops.
 template <typename ValueT, typename... RangeTs> class concat_range {
 public:
   using iterator =
       concat_iterator<ValueT,
                       decltype(std::begin(std::declval<RangeTs &>()))...>;
 
 private:
   std::tuple<RangeTs...> Ranges;
 
-  template <size_t... Ns> iterator begin_impl(std::index_sequence<Ns...>) {
+  template <size_t... Ns>
+  iterator begin_impl(std::index_sequence<Ns...>) const {
     return iterator(std::get<Ns>(Ranges)...);
   }
-  template <size_t... Ns> iterator end_impl(std::index_sequence<Ns...>) {
+  template <size_t... Ns> iterator end_impl(std::index_sequence<Ns...>) const {
     return iterator(make_range(std::end(std::get<Ns>(Ranges)),
                                std::end(std::get<Ns>(Ranges)))...);
   }
 
 public:
   concat_range(RangeTs &&... Ranges)
       : Ranges(std::forward<RangeTs>(Ranges)...) {}
 
-  iterator begin() { return begin_impl(std::index_sequence_for<RangeTs...>{}); }
-  iterator end() { return end_impl(std::index_sequence_for<RangeTs...>{}); }
+  iterator begin() const {
+    return begin_impl(std::index_sequence_for<RangeTs...>{});
+  }
+  iterator end() const {
+    return end_impl(std::index_sequence_for<RangeTs...>{});
+  }
 };
 
 } // end namespace detail
 
 /// Concatenated range across two or more ranges.
 ///
 /// The desired value type must be explicitly specified.
 template <typename ValueT, typename... RangeTs>

 
 template <typename R> class enumerator {
 public:
   explicit enumerator(R &&Range) : TheRange(std::forward<R>(Range)) {}
 
   enumerator_iter<R> begin() {
     return enumerator_iter<R>(0, std::begin(TheRange));
   }
+  enumerator_iter<R> begin() const {
+    return enumerator_iter<R>(0, std::begin(TheRange));
+  }
 
   enumerator_iter<R> end() {
     return enumerator_iter<R>(std::end(TheRange));
   }
+  enumerator_iter<R> end() const {
+    return enumerator_iter<R>(std::end(TheRange));
+  }
 
 private:
   R TheRange;
 };
 
 } // end namespace detail
 
 /// Given an input range, returns a new range whose values are are pair (A,B)

mlir/include/mlir/Support/IndentedOstream.h

 public:
   explicit raw_indented_ostream(llvm::raw_ostream &os) : os(os) {
     SetUnbuffered();
   }
 
   /// Simple RAII struct to use to indentation around entering/exiting region.
   struct DelimitedScope {
     explicit DelimitedScope(raw_indented_ostream &os, StringRef open = "",
-                            StringRef close = "")
-        : os(os), open(open), close(close) {
+                            StringRef close = "", bool indent = true)
+        : os(os), open(open), close(close), indent(indent) {
       os << open;
+      if (indent)
         os.indent();
     }
     ~DelimitedScope() {
+      if (indent)
         os.unindent();
       os << close;
     }
 
     raw_indented_ostream &os;
 
   private:
-    llvm::StringRef open, close;
+    StringRef open, close;
+    bool indent;
   };
 
   /// Returns the underlying (unindented) raw_ostream.
   raw_ostream &getOStream() const { return os; }
 
   /// Returns DelimitedScope.
-  DelimitedScope scope(StringRef open = "", StringRef close = "") {
-    return DelimitedScope(*this, open, close);
+  DelimitedScope scope(StringRef open = "", StringRef close = "",
+                       bool indent = true) {
+    return DelimitedScope(*this, open, close, indent);
   }
 
-  /// Re-indents by removing the leading whitespace from the first non-empty
-  /// line from every line of the string, skipping over empty lines at the
-  /// start.
-  raw_indented_ostream &reindent(StringRef str);
+  /// Prints a string re-indented to the current indent. Re-indents by removing
+  /// the leading whitespace from the first non-empty line from every line of
+  /// the string, skipping over empty lines at the start.
+  raw_indented_ostream &printReindented(StringRef str);
 
   /// Increases the indent and returning this raw_indented_ostream.
   raw_indented_ostream &indent() {
     currentIndent += indentSize;
     return *this;
   }
 
   /// Decreases the indent and returning this raw_indented_ostream.

mlir/include/mlir/TableGen/AttrOrTypeDef.h

 class DagInit;
 class Record;
 class SMLoc;
 } // namespace llvm
 
 namespace mlir {
 namespace tblgen {
 class Dialect;
-class AttrOrTypeParameter;
 
 //===----------------------------------------------------------------------===//
 // AttrOrTypeBuilder
 //===----------------------------------------------------------------------===//
 
 /// Wrapper class that represents a Tablegen AttrOrTypeBuilder.
 class AttrOrTypeBuilder : public Builder {
 public:
   using Builder::Builder;
 
   /// Returns true if this builder is able to infer the MLIRContext parameter.
   bool hasInferredContextParameter() const;
 };
 
 //===----------------------------------------------------------------------===//
+// AttrOrTypeParameter
+//===----------------------------------------------------------------------===//
+
+// A wrapper class for tblgen AttrOrTypeParameter, arrays of which belong to
+// AttrOrTypeDefs to parameterize them.
+class AttrOrTypeParameter {
+public:
+  explicit AttrOrTypeParameter(const llvm::DagInit *def, unsigned index)
+      : def(def), index(index) {}
+
+  // Get the parameter name.
+  StringRef getName() const;
+
+  // If specified, get the custom allocator code for this parameter.
+  Optional<StringRef> getAllocator() const;
+
+  // If specified, get the custom comparator code for this parameter.
+  Optional<StringRef> getComparator() const;
+
+  // Get the C++ type of this parameter.
+  StringRef getCppType() const;
+
+  // Get the C++ accessor type of this parameter.
+  StringRef getCppAccessorType() const;
+
+  // Get the C++ storage type of this parameter.
+  StringRef getCppStorageType() const;
+
+  // Get an optional C++ parameter parser.
+  Optional<StringRef> getParser() const;
+
+  // Get an optional C++ parameter printer.
+  Optional<StringRef> getPrinter() const;
+
+  // Get a description of this parameter for documentation purposes.
+  Optional<StringRef> getSummary() const;
+
+  // Get the assembly syntax documentation.
+  StringRef getSyntax() const;
+
+  // Return the underlying def of this parameter.
+  const llvm::Init *getDef() const;
+
+  // The parameter is pointer-comparable.
+  bool operator==(const AttrOrTypeParameter &other) const {
+    return def == other.def && index == other.index;
+  }
+  bool operator!=(const AttrOrTypeParameter &other) const {
+    return !(*this == other);
+  }
+
+private:
+  /// The underlying tablegen parameter list this parameter is a part of.
+  const llvm::DagInit *def;
+  /// The index of the parameter within the parameter list (`def`).
+  unsigned index;
+};
+
+//===----------------------------------------------------------------------===//
+// AttributeSelfTypeParameter
+//===----------------------------------------------------------------------===//
+
+// A wrapper class for the AttributeSelfTypeParameter tblgen class. This
+// represents a parameter of mlir::Type that is the value type of an AttrDef.
+class AttributeSelfTypeParameter : public AttrOrTypeParameter {
+public:
+  static bool classof(const AttrOrTypeParameter *param);
+};
+
+//===----------------------------------------------------------------------===//
 // AttrOrTypeDef
 //===----------------------------------------------------------------------===//
 
 /// Wrapper class that contains a TableGen AttrOrTypeDef's record and provides
 /// helper methods for accessing them.
 class AttrOrTypeDef {
 public:
   explicit AttrOrTypeDef(const llvm::Record *def);
public:
   StringRef getStorageNamespace() const;
 
   // Returns true if we should generate the storage class.
   bool genStorageClass() const;
 
   // Indicates whether or not to generate the storage class constructor.
   bool hasStorageCustomConstructor() const;
 
-  // Fill a list with this def's parameters. See AttrOrTypeDef in OpBase.td for
-  // documentation of parameter usage.
-  void getParameters(SmallVectorImpl<AttrOrTypeParameter> &) const;
+  /// Get the parameters of this attribute or type.
+  ArrayRef<AttrOrTypeParameter> getParameters() const { return parameters; }
 
   // Return the number of parameters
   unsigned getNumParameters() const;
 
   // Return the keyword/mnemonic to use in the printer/parser methods if we are
   // supposed to auto-generate them.
   Optional<StringRef> getMnemonic() const;
 
   // Returns the code to use as the types printer method. If not specified,
   // return a non-value. Otherwise, return the contents of that code block.
   Optional<StringRef> getPrinterCode() const;
 
   // Returns the code to use as the parser method. If not specified, returns
   // None. Otherwise, returns the contents of that code block.
   Optional<StringRef> getParserCode() const;
 
   // Returns the custom assembly format, if one was specified.
   Optional<StringRef> getAssemblyFormat() const;
 
+  // An attribute or type with parameters needs a parser.
+  bool needsParserPrinter() const { return getNumParameters() != 0; }
+
+  // Returns true if this attribute or type has a generated parser.
+  bool hasGeneratedParser() const {
+    return getParserCode() || getAssemblyFormat();
+  }
+
+  // Returns true if this attribute or type has a generated printer.
+  bool hasGeneratedPrinter() const {
+    return getPrinterCode() || getAssemblyFormat();
+  }
+
   // Returns true if the accessors based on the parameters should be generated.
   bool genAccessors() const;
 
   // Return true if we need to generate the verify declaration and getChecked
   // method.
   bool genVerifyDecl() const;
 
   // Returns the def's extra class declaration code.

 protected:
   const llvm::Record *def;
 
   // The builders of this definition.
   SmallVector<AttrOrTypeBuilder> builders;
 
   // The traits of this definition.
   SmallVector<Trait> traits;
+
+  /// The parameters of this attribute or type.
+  SmallVector<AttrOrTypeParameter> parameters;
 };
 
 //===----------------------------------------------------------------------===//
 // AttrDef
 //===----------------------------------------------------------------------===//
 
 /// This class represents a wrapper around a tablegen AttrDef record.
 class AttrDef : public AttrOrTypeDef {

 //===----------------------------------------------------------------------===//
 
 /// This class represents a wrapper around a tablegen TypeDef record.
 class TypeDef : public AttrOrTypeDef {
 public:
   using AttrOrTypeDef::AttrOrTypeDef;
 };
 
-//===----------------------------------------------------------------------===//
-// AttrOrTypeParameter
-//===----------------------------------------------------------------------===//
-
-// A wrapper class for tblgen AttrOrTypeParameter, arrays of which belong to
-// AttrOrTypeDefs to parameterize them.
-class AttrOrTypeParameter {
-public:
-  explicit AttrOrTypeParameter(const llvm::DagInit *def, unsigned index)
-      : def(def), index(index) {}
-
-  // Get the parameter name.
-  StringRef getName() const;
-
-  // If specified, get the custom allocator code for this parameter.
-  Optional<StringRef> getAllocator() const;
-
-  // If specified, get the custom comparator code for this parameter.
-  Optional<StringRef> getComparator() const;
-
-  // Get the C++ type of this parameter.
-  StringRef getCppType() const;
-
-  // Get the C++ accessor type of this parameter.
-  StringRef getCppAccessorType() const;
-
-  // Get the C++ storage type of this parameter.
-  StringRef getCppStorageType() const;
-
-  // Get an optional C++ parameter parser.
-  Optional<StringRef> getParser() const;
-
-  // Get an optional C++ parameter printer.
-  Optional<StringRef> getPrinter() const;
-
-  // Get a description of this parameter for documentation purposes.
-  Optional<StringRef> getSummary() const;
-
-  // Get the assembly syntax documentation.
-  StringRef getSyntax() const;
-
-  // Return the underlying def of this parameter.
-  const llvm::Init *getDef() const;
-
-private:
-  /// The underlying tablegen parameter list this parameter is a part of.
-  const llvm::DagInit *def;
-  /// The index of the parameter within the parameter list (`def`).
-  unsigned index;
-};
-
-//===----------------------------------------------------------------------===//
-// AttributeSelfTypeParameter
-//===----------------------------------------------------------------------===//
-
-// A wrapper class for the AttributeSelfTypeParameter tblgen class. This
-// represents a parameter of mlir::Type that is the value type of an AttrDef.
-class AttributeSelfTypeParameter : public AttrOrTypeParameter {
-public:
-  static bool classof(const AttrOrTypeParameter *param);
-};
-
 } // end namespace tblgen
 } // end namespace mlir
 
 #endif // MLIR_TABLEGEN_ATTRORTYPEDEF_H

mlir/include/mlir/TableGen/Class.h

 //===- Class.h - Helper classes for C++ code emission -----------*- 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 file defines several classes for Op C++ code emission. They are only
+// This file defines several classes for C++ code emission. They are only
 // expected to be used by MLIR TableGen backends.
 //
-// We emit the op declaration and definition into separate files: *Ops.h.inc
-// and *Ops.cpp.inc. The former is to be included in the dialect *Ops.h and
-// the latter for dialect *Ops.cpp. This way provides a cleaner interface.
+// We emit the declarations and definitions into separate files: *.h.inc and
+// *.cpp.inc. The former is to be included in the dialect *.h and the latter for
+// dialect *.cpp. This way provides a cleaner interface.
 //
 // In order to do this split, we need to track method signature and
 // implementation logic separately. Signature information is used for both
 // declaration and definition, while implementation logic is only for
 // definition. So we have the following classes for C++ code emission.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef MLIR_TABLEGEN_CLASS_H_
 #define MLIR_TABLEGEN_CLASS_H_
 
+#include "mlir/Support/IndentedOstream.h"
 #include "mlir/Support/LLVM.h"
 #include "mlir/TableGen/CodeGenHelpers.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
-#include "llvm/Support/raw_ostream.h"
 
 #include <set>
 #include <string>
 
 namespace mlir {
 namespace tblgen {
 class FmtObjectBase;
 
public:
   /// Create a method parameter with a C++ type, parameter name, and no default
   /// value.
   template <typename TypeT, typename NameT>
   MethodParameter(TypeT &&type, NameT &&name, bool optional = false)
       : MethodParameter(std::forward<TypeT>(type), std::forward<NameT>(name),
                         /*defaultValue=*/"", optional) {}
 
   /// Write the parameter as part of a method declaration.
-  void writeDeclTo(raw_ostream &os) const { writeTo(os, /*emitDefault=*/true); }
+  void writeDeclTo(raw_indented_ostream &os) const;
   /// Write the parameter as part of a method definition.
-  void writeDefTo(raw_ostream &os) const { writeTo(os, /*emitDefault=*/false); }
+  void writeDefTo(raw_indented_ostream &os) const;
 
   /// Get the C++ type.
-  const std::string &getType() const { return type; }
+  StringRef getType() const { return type; }
   /// Returns true if the parameter has a default value.
   bool hasDefaultValue() const { return !defaultValue.empty(); }
 
 private:
-  void writeTo(raw_ostream &os, bool emitDefault) const;
-
   /// The C++ type.
   std::string type;
   /// The variable name.
   std::string name;
   /// An optional default value. The default value exists if the string is not
   /// empty.
   std::string defaultValue;
   /// Whether the parameter should be indicated as "optional".
   bool optional;
 };
 
 /// This class contains a list of method parameters for constructor, class
 /// methods, and method signatures.
 class MethodParameters {
 public:
   /// Create a list of method parameters.
   MethodParameters(std::initializer_list<MethodParameter> parameters)
       : parameters(parameters) {}
   MethodParameters(SmallVector<MethodParameter> parameters)
       : parameters(std::move(parameters)) {}
 
   /// Write the parameters as part of a method declaration.
-  void writeDeclTo(raw_ostream &os) const;
+  void writeDeclTo(raw_indented_ostream &os) const;
   /// Write the parameters as part of a method definition.
-  void writeDefTo(raw_ostream &os) const;
+  void writeDefTo(raw_indented_ostream &os) const;
 
   /// Determine whether this list of parameters "subsumes" another, which occurs
   /// when this parameter list is identical to the other and has zero or more
   /// additional default-valued parameters.
   bool subsumes(const MethodParameters &other) const;
 
   /// Return the number of parameters.
   unsigned getNumParameters() const { return parameters.size(); }
 
 private:
-  llvm::SmallVector<MethodParameter> parameters;
+  /// The list of parameters.
+  SmallVector<MethodParameter> parameters;
 };
 
 /// This class contains the signature of a C++ method, including the return
 /// type. method name, and method parameters.
 class MethodSignature {
 public:
-  MethodSignature(StringRef retType, StringRef name,
+  /// Create a method signature with a return type, a method name, and a list of
+  /// parameters. Take ownership of the list.
+  template <typename RetTypeT, typename NameT>
+  MethodSignature(RetTypeT &&retType, NameT &&name,
                   SmallVector<MethodParameter> &&parameters)
-      : returnType(retType), methodName(name),
+      : returnType(stringify(std::forward<RetTypeT>(retType))),
+        methodName(stringify(std::forward<NameT>(name))),
         parameters(std::move(parameters)) {}
-  template <typename... Parameters>
-  MethodSignature(StringRef retType, StringRef name, Parameters &&...parameters)
-      : returnType(retType), methodName(name),
-        parameters({std::forward<Parameters>(parameters)...}) {}
+  /// Create a method signature with a return type, a method name, and a list of
+  /// parameters.
+  template <typename RetTypeT, typename NameT>
+  MethodSignature(RetTypeT &&retType, NameT &&name,
+                  ArrayRef<MethodParameter> parameters)
+      : MethodSignature(std::forward<RetTypeT>(retType),
+                        std::forward<NameT>(name),
+                        SmallVector<MethodParameter>(parameters.begin(),
+                                                     parameters.end())) {}
+  /// Create a method signature with a return type, a method name, and a
+  /// variadic list of parameters.
+  template <typename RetTypeT, typename NameT, typename... Parameters>
+  MethodSignature(RetTypeT &&retType, NameT &&name, Parameters &&...parameters)
+      : MethodSignature(std::forward<RetTypeT>(retType),
+                        std::forward<NameT>(name),
+                        ArrayRef<MethodParameter>(
+                            {std::forward<Parameters>(parameters)...})) {}
 
   /// Determine whether a method with this signature makes a method with
   /// `other` signature redundant. This occurs if the signatures have the same
   /// name and this signature's parameteres subsume the other's.
   ///
   /// A method that makes another method redundant with a different return type
   /// can replace the other, the assumption being that the subsuming method
   /// provides a more resolved return type, e.g. IntegerAttr vs. Attribute.
   bool makesRedundant(const MethodSignature &other) const;
 
   /// Get the name of the method.
   StringRef getName() const { return methodName; }
 
   /// Get the number of parameters.
   unsigned getNumParameters() const { return parameters.getNumParameters(); }
 
   /// Write the signature as part of a method declaration.
-  void writeDeclTo(raw_ostream &os) const;
+  void writeDeclTo(raw_indented_ostream &os) const;
 
   /// Write the signature as part of a method definition. `namePrefix` is to be
   /// prepended to the method name (typically namespaces for qualifying the
   /// method definition).
-  void writeDefTo(raw_ostream &os, StringRef namePrefix) const;
+  void writeDefTo(raw_indented_ostream &os, StringRef namePrefix) const;
 
 private:
   /// The method's C++ return type.
   std::string returnType;
   /// The method name.
   std::string methodName;
   /// The method's parameter list.
   MethodParameters parameters;
 };
 
-/// Class for holding the body of an op's method for C++ code emission
+/// This class contains the body of a C++ method.
 class MethodBody {
 public:
-  explicit MethodBody(bool declOnly);
-
-  MethodBody &operator<<(Twine content);
-  MethodBody &operator<<(int content);
-  MethodBody &operator<<(const FmtObjectBase &content);
+  /// Create a method body, indicating whether it should be elided for methods
+  /// that are declaration-only.
+  MethodBody(bool declOnly);
+
+  /// Define a move constructor to correctly initialize the streams.
+  MethodBody(MethodBody &&other)
+      : declOnly(other.declOnly), body(std::move(other.body)), stringOs(body),
+        os(stringOs) {}
+
+  /// Write a value to the method body.
+  template <typename ValueT>
+  MethodBody &operator<<(ValueT &&value) {
+    if (!declOnly) {
+      os << std::forward<ValueT>(value);
+      os.flush();
+    }
+    return *this;
+  }
+
+  /// Write the method body to the output stream. The body can be written as
+  /// part of the declaration of an inline method or just in the definition.
+  void writeTo(raw_indented_ostream &os) const;
+
+  /// Indent the output stream.
+  MethodBody &indent() {
+    os.indent();
+    return *this;
+  }
+  /// Unindent the output stream.
+  MethodBody &unindent() {
+    os.unindent();
+    return *this;
+  }
+  /// Create a delimited scope: immediately print `open`, indent if `indent` is
+  /// true, and print `close` on object destruction.
+  raw_indented_ostream::DelimitedScope
+  scope(StringRef open = "", StringRef close = "", bool indent = false) {
+    return os.scope(open, close, indent);
+  }
 
-  void writeTo(raw_ostream &os) const;
+  /// Get the underlying indented output stream.
+  raw_indented_ostream &getStream() { return os; }
 
 private:
-  /// Whether this class should record method body.
-  bool isEffective;
-  /// The body of the method.
+  /// Whether the body should be elided.
+  bool declOnly;
+  /// The body data.
   std::string body;
+  /// The string output stream.
+  llvm::raw_string_ostream stringOs;
+  /// An indented output stream for formatting input.
+  raw_indented_ostream os;
+};
+
+/// A class declaration is a class element that appears as part of its
+/// declaration.
+class ClassDeclaration {
+public:
+  virtual ~ClassDeclaration() = default;
+
+  /// Kinds for LLVM-style RTTI.
+  enum Kind {
+    Method,
+    UsingDeclaration,
+    VisibilityDeclaration,
+    Field,
+    ExtraClassDeclaration
+  };
+  /// Create a class declaration with a given kind.
+  ClassDeclaration(Kind kind) : kind(kind) {}
+
+  /// Get the class declaration kind.
+  Kind getKind() const { return kind; }
+
+  /// Write the declaration.
+  virtual void writeDeclTo(raw_indented_ostream &os) const = 0;
+
+  /// Write the definition, if any. `namePrefix` is the namespace prefix, which
+  /// may contains a class name.
+  virtual void writeDefTo(raw_indented_ostream &os,
+                          StringRef namePrefix) const {}
+
+private:
+  /// The class declaration kind.
+  Kind kind;
+};
+
+/// Base class for class declarations.
+template <ClassDeclaration::Kind DeclKind>
+class ClassDeclarationBase : public ClassDeclaration {
+public:
+  using Base = ClassDeclarationBase<DeclKind>;
+  ClassDeclarationBase() : ClassDeclaration(DeclKind) {}
+
+  static bool classof(const ClassDeclaration *other) {
+    return other->getKind() == DeclKind;
+  }
 };
 
 /// Class for holding an op's method for C++ code emission
-class Method {
+class Method : public ClassDeclarationBase<ClassDeclaration::Method> {
 public:
   /// Properties (qualifiers) of class methods. Bitfield is used here to help
   /// querying properties.
-  enum Property {
-    MP_None = 0x0,
-    MP_Static = 0x1,
-    MP_Constructor = 0x2,
-    MP_Private = 0x4,
-    MP_Declaration = 0x8,
-    MP_Inline = 0x10,
-    MP_Constexpr = 0x20 | MP_Inline,
-    MP_StaticDeclaration = MP_Static | MP_Declaration,
-  };
-
-  template <typename... Args>
-  Method(StringRef retType, StringRef name, Property property, Args &&...args)
-      : properties(property),
-        methodSignature(retType, name, std::forward<Args>(args)...),
-        methodBody(properties & MP_Declaration) {}
+  enum Properties {
+    None = 0x0,
+    Static = 0x1,
+    Constructor = 0x2,
+    Private = 0x4,
+    Declaration = 0x8,
+    Inline = 0x10,
+    ConstexprValue = 0x20,
+    Const = 0x40,
+
+    Constexpr = ConstexprValue | Inline,
+    StaticDeclaration = Static | Declaration,
+    StaticInline = Static | Inline,
+    ConstInline = Const | Inline,
+    ConstDeclaration = Const | Declaration
+  };
+
+  /// Create a method with a return type, a name, method properties, and a some
+  /// parameters. The parameteres may be passed as a list or as a variadic pack.
+  template <typename RetTypeT, typename NameT, typename... Args>
+  Method(RetTypeT &&retType, NameT &&name, Properties properties,
+         Args &&...args)
+      : properties(properties),
+        methodSignature(std::forward<RetTypeT>(retType),
+                        std::forward<NameT>(name), std::forward<Args>(args)...),
+        methodBody(properties & Declaration) {}
+  /// Create a method with a return type, a name, method properties, and a list
+  /// of parameters.
+  Method(StringRef retType, StringRef name, Properties properties,
+         std::initializer_list<MethodParameter> params)
+      : properties(properties), methodSignature(retType, name, params),
+        methodBody(properties & Declaration) {}
 
+  // Define move constructor and assignment operator to prevent copying.
   Method(Method &&) = default;
   Method &operator=(Method &&) = default;
 
-  virtual ~Method() = default;
-
+  /// Get the method body.
   MethodBody &body() { return methodBody; }
 
   /// Returns true if this is a static method.
-  bool isStatic() const { return properties & MP_Static; }
+  bool isStatic() const { return properties & Static; }
 
   /// Returns true if this is a private method.
-  bool isPrivate() const { return properties & MP_Private; }
+  bool isPrivate() const { return properties & Private; }
 
   /// Returns true if this is an inline method.
-  bool isInline() const { return properties & MP_Inline; }
+  bool isInline() const { return properties & Inline; }
+
+  /// Returns true if this is a constructor.
+  bool isConstructor() const { return properties & Constructor; }
+
+  /// Returns true if this class method is const.
+  bool isConst() const { return properties & Const; }
 
   /// Returns the name of this method.
   StringRef getName() const { return methodSignature.getName(); }
 
   /// Returns if this method makes the `other` method redundant.
   bool makesRedundant(const Method &other) const {
     return methodSignature.makesRedundant(other.methodSignature);
   }
 
-  /// Writes the method as a declaration to the given `os`.
-  virtual void writeDeclTo(raw_ostream &os) const;
+  /// Write the method declaration, including the definition if inline.
+  void writeDeclTo(raw_indented_ostream &os) const override;
 
-  /// Writes the method as a definition to the given `os`. `namePrefix` is the
-  /// prefix to be prepended to the method name (typically namespaces for
-  /// qualifying the method definition).
-  virtual void writeDefTo(raw_ostream &os, StringRef namePrefix) const;
+  /// Write the method definition. This is a no-op for inline methods.
+  void writeDefTo(raw_indented_ostream &os,
+                  StringRef namePrefix) const override;
 
 protected:
   /// A collection of method properties.
-  Property properties;
+  Properties properties;
   /// The signature of the method.
   MethodSignature methodSignature;
   /// The body of the method, if it has one.
   MethodBody methodBody;
 };
 
+/// This enum describes C++ inheritance visibility.
+enum class Visibility { Public, Protected, Private };
+
+/// Write "public", "protected", or "private".
+llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
+                              mlir::tblgen::Visibility visibility);
+
+// Class for holding an op's constructor method for C++ code emission.
+class Constructor : public Method {
+public:
+  /// Create a constructor for a given class, with method properties, and
+  /// parameters specified either as a list of a variadic pack.
+  template <typename NameT, typename... Args>
+  Constructor(NameT &&className, Properties properties, Args &&...args)
+      : Method("", std::forward<NameT>(className), properties,
+               std::forward<Args>(args)...) {}
+
+  /// Add member initializer to constructor initializing `name` with `value`.
+  template <typename NameT, typename ValueT>
+  void addMemberInitializer(NameT &&name, ValueT &&value) {
+    initializers.emplace_back(stringify(std::forward<NameT>(name)),
+                              stringify(std::forward<ValueT>(value)));
+  }
+
+  /// Write the declaration of the constructor, and its definition if inline.
+  void writeDeclTo(raw_indented_ostream &os) const override;
+
+  /// Write the definition of the constructor if it is not inline.
+  void writeDefTo(raw_indented_ostream &os,
+                  StringRef namePrefix) const override;
+
+  /// Return true if a method is a constructor.
+  static bool classof(const ClassDeclaration *other) {
+    return isa<Method>(other) && cast<Method>(other)->isConstructor();
+  }
+
+  /// Initialization of a class field in a constructor.
+  class MemberInitializer {
+  public:
+    /// Create a member initializer in a constructor that initializes the class
+    /// field `name` with `value`.
+    MemberInitializer(std::string name, std::string value)
+        : name(std::move(name)), value(std::move(value)) {}
+
+    /// Write the member initializer.
+    void writeTo(raw_indented_ostream &os) const;
+
+  private:
+    /// The name of the class field.
+    std::string name;
+    /// The value with which to initialize it.
+    std::string value;
+  };
+
+private:
+  /// The list of member initializers.
+  SmallVector<MemberInitializer> initializers;
+};
+
 } // end namespace tblgen
 } // end namespace mlir
 
 /// The OR of two method properties should return method properties. Ensure that
 /// this function is visible to `Class`.
-inline constexpr mlir::tblgen::Method::Property
-operator|(mlir::tblgen::Method::Property lhs,
-          mlir::tblgen::Method::Property rhs) {
-  return mlir::tblgen::Method::Property(static_cast<unsigned>(lhs) |
+inline constexpr mlir::tblgen::Method::Properties
+operator|(mlir::tblgen::Method::Properties lhs,
+          mlir::tblgen::Method::Properties rhs) {
+  return mlir::tblgen::Method::Properties(static_cast<unsigned>(lhs) |
                                           static_cast<unsigned>(rhs));
 }
 
+/// Select a property with a bool. This allows expressions like:
+///
+///   props |= Method::Constructor & isConstructor();
+///
+inline constexpr mlir::tblgen::Method::Properties
+operator&(mlir::tblgen::Method::Properties lhs, bool rhs) {
+  return rhs ? lhs : mlir::tblgen::Method::None;
+}
+inline constexpr bool operator&(mlir::tblgen::Method::Properties lhs,
+                                mlir::tblgen::Method::Properties rhs) {
+  return static_cast<unsigned>(lhs) & static_cast<unsigned>(rhs);
+}
+
 namespace mlir {
 namespace tblgen {
 
-/// Class for holding an op's constructor method for C++ code emission.
-class Constructor : public Method {
+/// This class describes a C++ parent class declaration.
+class ParentClass {
 public:
-  template <typename... Parameters>
-  Constructor(StringRef className, Property property,
-              Parameters &&...parameters)
-      : Method("", className, property,
-               std::forward<Parameters>(parameters)...) {}
+  /// Create a parent class with a class name and visibility.
+  template <typename NameT>
+  ParentClass(NameT &&name, Visibility visibility = Visibility::Public)
+      : name(stringify(std::forward<NameT>(name))), visibility(visibility) {}
+
+  /// Add a template parameter.
+  template <typename ParamT>
+  void addTemplateParam(ParamT param) {
+    templateParams.insert(stringify(param));
+  }
+  /// Add a list of template parameters.
+  template <typename ContainerT>
+  void addTemplateParams(ContainerT &&container) {
+    templateParams.insert(std::begin(container), std::end(container));
+  }
 
-  /// Add member initializer to constructor initializing `name` with `value`.
-  void addMemberInitializer(StringRef name, StringRef value);
+  /// Write the parent class declaration.
+  void writeTo(raw_indented_ostream &os) const;
+
+private:
+  /// The fully resolved C++ name of the parent class.
+  std::string name;
+  /// The visibility of the parent class.
+  Visibility visibility;
+  /// An optional list of class template parameters.
+  SetVector<std::string, SmallVector<std::string>, StringSet<>> templateParams;
+};
+
+/// This class describes a using-declaration for a class. E.g.
+///
+///   using Op::Op;
+///   using Adaptor = OpAdaptor;
+///
+class UsingDeclaration
+    : public ClassDeclarationBase<ClassDeclaration::UsingDeclaration> {
+public:
+  /// Create a using declaration that either aliases `name` to `value` or
+  /// inherits the parent methods `name.
+  template <typename NameT, typename ValueT = std::string>
+  UsingDeclaration(NameT &&name, ValueT &&value = "")
+      : name(stringify(std::forward<NameT>(name))),
+        value(stringify(std::forward<ValueT>(value))) {}
+
+  /// Write the using declaration.
+  void writeDeclTo(raw_indented_ostream &os) const override;
+
+private:
+  /// The name of the declaration, or a resolved name to an inherited function.
+  std::string name;
+  /// The type that is being aliased. Leave empty for inheriting functions.
+  std::string value;
+};
+
+/// This class describes a class field.
+class Field : public ClassDeclarationBase<ClassDeclaration::Field> {
+public:
+  /// Create a class field with a type and variable name.
+  template <typename TypeT, typename NameT>
+  Field(TypeT &&type, NameT &&name)
+      : type(stringify(std::forward<TypeT>(type))),
+        name(stringify(std::forward<NameT>(name))) {}
+
+  /// Write the declaration of the field.
+  void writeDeclTo(raw_indented_ostream &os) const override;
+
+private:
+  /// The C++ type of the field.
+  std::string type;
+  /// The variable name of the class whether.
+  std::string name;
+};
+
+/// A declaration for the visibility of subsequent declarations.
+class VisibilityDeclaration
+    : public ClassDeclarationBase<ClassDeclaration::VisibilityDeclaration> {
+public:
+  /// Create a declaration for the given visibility.
+  VisibilityDeclaration(Visibility visibility) : visibility(visibility) {}
+
+  /// Get the visibility.
+  Visibility getVisibility() const { return visibility; }
+
+  /// Write the visibility declaration.
+  void writeDeclTo(raw_indented_ostream &os) const override;
+
+private:
+  /// The visibility of subsequent class declarations.
+  Visibility visibility;
+};
+
+/// Unstructured extra class declarations, from TableGen definitions. The
+/// default visibility of extra class declarations is up to the owning class.
+class ExtraClassDeclaration
+    : public ClassDeclarationBase<ClassDeclaration::ExtraClassDeclaration> {
+public:
+  /// Create an extra class declaration.
+  ExtraClassDeclaration(StringRef extraClassDeclaration)
+      : extraClassDeclaration(extraClassDeclaration) {}
 
-  /// Writes the method as a definition to the given `os`. `namePrefix` is the
-  /// prefix to be prepended to the method name (typically namespaces for
-  /// qualifying the method definition).
-  void writeDefTo(raw_ostream &os, StringRef namePrefix) const override;
+  /// Write the extra class declarations.
+  void writeDeclTo(raw_indented_ostream &os) const override;
 
 private:
-  /// Member initializers.
-  std::string memberInitializers;
+  /// The string of the extra class declarations. It is re-indented before
+  /// printed.
+  StringRef extraClassDeclaration;
 };
 
 /// A class used to emit C++ classes from Tablegen.  Contains a list of public
 /// methods and a list of private fields to be emitted.
 class Class {
 public:
-  explicit Class(StringRef name);
+  virtual ~Class() = default;
+
+  /// Create a class with a name, and whether it should be declared as a `class`
+  /// or `struct`.
+  template <typename NameT>
+  Class(NameT &&name, bool isStruct = false)
+      : className(stringify(std::forward<NameT>(name))), isStruct(isStruct) {}
 
   /// Add a new constructor to this class and prune and constructors made
   /// redundant by it. Returns null if the constructor was not added. Else,
   /// returns a pointer to the new constructor.
-  template <typename... Parameters>
-  Constructor *addConstructorAndPrune(Parameters &&...parameters) {
-    return addConstructorAndPrune(
-        Constructor(getClassName(), Method::MP_Constructor,
-                    std::forward<Parameters>(parameters)...));
+  template <Method::Properties Properties = Method::None, typename... Args>
+  Constructor *addConstructor(Args &&...args) {
+    return addConstructorAndPrune(Constructor(getClassName(),
+                                              Properties | Method::Constructor,
+                                              std::forward<Args>(args)...));
   }
 
   /// Add a new method to this class and prune any methods made redundant by it.
   /// Returns null if the method was not added (because an existing method would
   /// make it redundant). Else, returns a pointer to the new method.
-  template <typename... Parameters>
-  Method *addMethod(StringRef retType, StringRef name,
-                    Method::Property properties, Parameters &&...parameters) {
-    return addMethodAndPrune(Method(retType, name, properties,
-                                    std::forward<Parameters>(parameters)...));
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *addMethod(RetTypeT &&retType, NameT &&name,
+                    Method::Properties properties, Args &&...args) {
+    return addMethodAndPrune(
+        Method(std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+               Properties | properties, std::forward<Args>(args)...));
   }
 
   /// Add a method with statically-known properties.
-  template <Method::Property Properties = Method::MP_None,
-            typename... Parameters>
-  Method *addMethod(StringRef retType, StringRef name,
-                    Parameters &&...parameters) {
-    return addMethod(retType, name, Properties,
-                             std::forward<Parameters>(parameters)...);
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *addMethod(RetTypeT &&retType, NameT &&name, Args &&...args) {
+    return addMethod(std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+                     Properties, std::forward<Args>(args)...);
   }
 
   /// Add a static method.
-  template <Method::Property Properties = Method::MP_None,
-            typename... Parameters>
-  Method *addStaticMethod(StringRef retType, StringRef name,
-                          Parameters &&...parameters) {
-    return addMethod<Properties | Method::MP_Static>(
-        retType, name, std::forward<Parameters>(parameters)...);
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *addStaticMethod(RetTypeT &&retType, NameT &&name, Args &&...args) {
+    return addMethod<Properties | Method::Static>(
+        std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+        std::forward<Args>(args)...);
   }
 
   /// Add an inline static method.
-  template <Method::Property Properties = Method::MP_None,
-            typename... Parameters>
-  Method *addStaticInlineMethod(StringRef retType, StringRef name,
-                                Parameters &&...parameters) {
-    return addMethod<Properties | Method::MP_Static | Method::MP_Inline>(
-        retType, name, std::forward<Parameters>(parameters)...);
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *addStaticInlineMethod(RetTypeT &&retType, NameT &&name,
+                                Args &&...args) {
+    return addMethod<Properties | Method::Static | Method::Inline>(
+        std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+        std::forward<Args>(args)...);
   }
 
   /// Add an inline method.
-  template <Method::Property Properties = Method::MP_None,
-            typename... Parameters>
-  Method *addInlineMethod(StringRef retType, StringRef name,
-                          Parameters &&...parameters) {
-    return addMethod<Properties | Method::MP_Inline>(
-        retType, name, std::forward<Parameters>(parameters)...);
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *addInlineMethod(RetTypeT &&retType, NameT &&name, Args &&...args) {
+    return addMethod<Properties | Method::Inline>(
+        std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+        std::forward<Args>(args)...);
+  }
+
+  /// Add a const method.
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *addConstMethod(RetTypeT &&retType, NameT &&name, Args &&...args) {
+    return addMethod<Properties | Method::Const>(
+        std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+        std::forward<Args>(args)...);
   }
 
   /// Add a declaration for a method.
-  template <Method::Property Properties = Method::MP_None,
-            typename... Parameters>
-  Method *declareMethod(StringRef retType, StringRef name,
-                        Parameters &&...parameters) {
-    return addMethod<Properties | Method::MP_Declaration>(
-        retType, name, std::forward<Parameters>(parameters)...);
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *declareMethod(RetTypeT &&retType, NameT &&name, Args &&...args) {
+    return addMethod<Properties | Method::Declaration>(
+        std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+        std::forward<Args>(args)...);
   }
 
   /// Add a declaration for a static method.
-  template <Method::Property Properties = Method::MP_None,
-            typename... Parameters>
-  Method *declareStaticMethod(StringRef retType, StringRef name,
-                              Parameters &&...parameters) {
-    return addMethod<Properties | Method::MP_StaticDeclaration>(
-        retType, name, std::forward<Parameters>(parameters)...);
-  }
-
-  /// Creates a new field in this class.
-  void newField(StringRef type, StringRef name, StringRef defaultValue = "");
-
-  /// Writes this op's class as a declaration to the given `os`.
-  void writeDeclTo(raw_ostream &os) const;
-  /// Writes the method definitions in this op's class to the given `os`.
-  void writeDefTo(raw_ostream &os) const;
+  template <Method::Properties Properties = Method::None, typename RetTypeT,
+            typename NameT, typename... Args>
+  Method *declareStaticMethod(RetTypeT &&retType, NameT &&name,
+                              Args &&...args) {
+    return addMethod<Properties | Method::StaticDeclaration>(
+        std::forward<RetTypeT>(retType), std::forward<NameT>(name),
+        std::forward<Args>(args)...);
+  }
+
+  /// Add a new field to the class. Class fields added this way are always
+  /// private.
+  template <typename TypeT, typename NameT>
+  void addField(TypeT &&type, NameT &&name) {
+    fields.emplace_back(std::forward<TypeT>(type), std::forward<NameT>(name));
+  }
 
-  /// Returns the C++ class name of the op.
+  /// Add a parent class.
+  ParentClass &addParent(ParentClass parent);
+
+  /// Return the C++ name of the class.
   StringRef getClassName() const { return className; }
 
-protected:
-  /// Get a list of all the methods to emit, filtering out hidden ones.
-  void forAllMethods(llvm::function_ref<void(const Method &)> func) const {
-    llvm::for_each(constructors, [&](auto &ctor) { func(ctor); });
-    llvm::for_each(methods, [&](auto &method) { func(method); });
+  /// Write the declaration of this class, all declarations, and definitions of
+  /// inline functions. Wrap the output stream in an indented stream.
+  void writeDeclTo(raw_ostream &rawOs) const {
+    raw_indented_ostream os(rawOs);
+    writeDeclTo(os);
+  }
+  /// Write the definitions of thiss class's out-of-line constructors and
+  /// methods. Wrap the output stream in an indented stream.
+  void writeDefTo(raw_ostream &rawOs) const {
+    raw_indented_ostream os(rawOs);
+    writeDefTo(os);
+  }
+
+  /// Write the declaration of this class, all declarations, and definitions of
+  /// inline functions.
+  void writeDeclTo(raw_indented_ostream &os) const;
+  /// Write the definitions of thiss class's out-of-line constructors and
+  /// methods.
+  void writeDefTo(raw_indented_ostream &os) const;
+
+  /// Add a declaration. The declaration is appended directly to the list of
+  /// class declarations.
+  template <typename DeclT, typename... Args>
+  DeclT *declare(Args &&...args) {
+    auto decl = std::make_unique<DeclT>(std::forward<Args>(args)...);
+    auto *ret = decl.get();
+    declarations.push_back(std::move(decl));
+    return ret;
   }
 
+  /// The declaration of a class needs to be "finalized".
+  ///
+  /// Class constructors, methods, and fields can be added in any order,
+  /// regardless of whether they are public or private. These are stored in
+  /// lists separate from list of declarations `declarations`.
+  ///
+  /// So that the generated C++ code is somewhat organised, public methods are
+  /// declared together, and so are private methods and class fields. This
+  /// function iterates through all the added methods and fields and organises
+  /// them into the list of declarations, adding visibility declarations as
+  /// needed, as follows:
+  ///
+  ///   1. public methods and constructors
+  ///   2. private methods and constructors
+  ///   3. class fields -- all are private
+  ///
+  /// `Class::finalize` clears the lists of pending methods and fields, and can
+  /// be called multiple times.
+  virtual void finalize();
+
+protected:
   /// Add a new constructor if it is not made redundant by any existing
   /// constructors and prune and existing constructors made redundant.
   Constructor *addConstructorAndPrune(Constructor &&newCtor);
   /// Add a new method if it is not made redundant by any existing methods and
   /// prune and existing methods made redundant.
   Method *addMethodAndPrune(Method &&newMethod);
 
+  /// Get the last visibility declaration.
+  Visibility getLastVisibilityDecl() const;
+
   /// The C++ class name.
   std::string className;
-  /// The list of constructors.
-  std::vector<Constructor> constructors;
-  /// The list of class methods.
-  std::vector<Method> methods;
-  /// The list of class members.
-  SmallVector<std::string, 4> fields;
-};
+  /// The list of parent classes.
+  SmallVector<ParentClass> parents;
+  /// The pending list of methods and constructors.
+  std::vector<std::unique_ptr<Method>> methods;
+  /// The pending list of private class fields.
+  SmallVector<Field> fields;
+  /// Whether this is a `class` or a `struct`.
+  bool isStruct;
 
-// Class for holding an op for C++ code emission
-class OpClass : public Class {
-public:
-  explicit OpClass(StringRef name, StringRef extraClassDeclaration = "");
-
-  /// Adds an op trait.
-  void addTrait(Twine trait);
-
-  /// Writes this op's class as a declaration to the given `os`.  Redefines
-  /// Class::writeDeclTo to also emit traits and extra class declarations.
-  void writeDeclTo(raw_ostream &os) const;
-
-private:
-  StringRef extraClassDeclaration;
-  llvm::SetVector<std::string, SmallVector<std::string>, StringSet<>> traits;
+  /// A list of declarations in the class, emitted in order.
+  std::vector<std::unique_ptr<ClassDeclaration>> declarations;
 };
 
 } // namespace tblgen
 } // namespace mlir
 
 #endif // MLIR_TABLEGEN_CLASS_H_

mlir/include/mlir/TableGen/CodeGenHelpers.h

 class RecordKeeper;
 } // namespace llvm
 
 namespace mlir {
 namespace tblgen {
 class Constraint;
 class DagLeaf;
 
+// Format into a std::string
+template <typename... Parameters>
+std::string strfmt(const char *fmt, Parameters &&...parameters) {
+  return llvm::formatv(fmt, std::forward<Parameters>(parameters)...).str();
+}
+
 // Simple RAII helper for defining ifdef-undef-endif scopes.
 class IfDefScope {
 public:
   IfDefScope(llvm::StringRef name, llvm::raw_ostream &os)
       : name(name.str()), os(os) {
     os << "#ifdef " << name << "\n"
        << "#undef " << name << "\n\n";
   }
NamespaceEmitter(raw_ostream &os, const Dialect &dialect) : os(os) {
     emitNamespaceStarts(os, dialect.getCppNamespace());
   }
   NamespaceEmitter(raw_ostream &os, StringRef cppNamespace) : os(os) {
     emitNamespaceStarts(os, cppNamespace);
   }
 
   ~NamespaceEmitter() {
     for (StringRef ns : llvm::reverse(namespaces))
-      os << "} // namespace " << ns << "\n";
+      os << "} // end namespace " << ns << "\n";
   }
 
 private:
   void emitNamespaceStarts(raw_ostream &os, StringRef cppNamespace) {
     llvm::SplitString(cppNamespace, namespaces, "::");
     for (StringRef ns : namespaces)
       os << "namespace " << ns << " {\n";
   }
template <typename T> static std::string apply(T &&t) {
     return std::string(std::forward<T>(t));
   }
 };
 template <> struct stringifier<Twine> {
   static std::string apply(const Twine &twine) {
     return twine.str();
   }
 };
+template <typename OptionalT>
+struct stringifier<Optional<OptionalT>> {
+  static std::string apply(Optional<OptionalT> optional) {
+    return optional.hasValue() ? stringifier<OptionalT>::apply(*optional)
+                               : std::string();
+  }
+};
 } // end namespace detail
 
 /// Generically convert a value to a std::string.
 template <typename T> std::string stringify(T &&t) {
   return detail::stringifier<std::remove_reference_t<std::remove_const_t<T>>>::
       apply(std::forward<T>(t));
 }
 
 } // namespace tblgen
 } // namespace mlir
 
 #endif // MLIR_TABLEGEN_CODEGENHELPERS_H

mlir/include/mlir/TableGen/Format.h

enum class PHKind : char {
     Custom,  // For custom placeholders
     Builder, // For the $_builder placeholder
     Op,      // For the $_op placeholder
     Self,    // For the $_self placeholder
   };
 
   FmtContext() = default;
 
+  // Create a format context with a list of substitutions.
+  FmtContext(ArrayRef<std::pair<StringRef, StringRef>> subs);
+
   // Setter for custom placeholders
-  FmtContext &addSubst(StringRef placeholder, Twine subst);
+  FmtContext &addSubst(StringRef placeholder, const Twine &subst);
 
   // Setters for builtin placeholders
   FmtContext &withBuilder(Twine subst);
   FmtContext &withOp(Twine subst);
   FmtContext &withSelf(Twine subst);
 
   Optional<StringRef> getSubstFor(PHKind placeholder) const;
   Optional<StringRef> getSubstFor(StringRef placeholder) const;

mlir/lib/Support/IndentedOstream.cpp

 // where indentation helps readability.
 //
 //===----------------------------------------------------------------------===//
 
 #include "mlir/Support/IndentedOstream.h"
 
 using namespace mlir;
 
-raw_indented_ostream &mlir::raw_indented_ostream::reindent(StringRef str) {
-  StringRef remaining = str;
-  // Find leading whitespace indent.
-  while (!remaining.empty()) {
-    auto split = remaining.split('\n');
+raw_indented_ostream &
+mlir::raw_indented_ostream::printReindented(StringRef str) {
+  StringRef output = str;
+  // Skip empty lines.
+  while (!output.empty()) {
+    auto split = output.split('\n');
     size_t indent = split.first.find_first_not_of(" \t");
     if (indent != StringRef::npos) {
+      // Set an initial value.
       leadingWs = indent;
       break;
     }
+    output = split.second;
+  }
+  // Determine the maximum indent.
+  StringRef remaining = output;
+  while (!remaining.empty()) {
+    auto split = remaining.split('\n');
+    size_t indent = split.first.find_first_not_of(" \t");
+    if (indent != StringRef::npos)
+      leadingWs = std::min(leadingWs, static_cast<int>(indent));
     remaining = split.second;
   }
   // Print, skipping the empty lines.
-  *this << remaining;
+  *this << output;
   leadingWs = 0;
   return *this;
 }
 
 void mlir::raw_indented_ostream::write_impl(const char *ptr, size_t size) {
   StringRef str(ptr, size);
   // Print out indented.
   auto print = [this](StringRef str) {

mlir/lib/TableGen/AttrOrTypeDef.cpp

AttrOrTypeDef::AttrOrTypeDef(const llvm::Record *def) : def(def) {
   // Populate the traits.
   if (auto *traitList = def->getValueAsListInit("traits")) {
     SmallPtrSet<const llvm::Init *, 32> traitSet;
     traits.reserve(traitSet.size());
     for (auto *traitInit : *traitList)
       if (traitSet.insert(traitInit).second)
         traits.push_back(Trait::create(traitInit));
   }
+
+  // Populate the parameters.
+  if (auto *parametersDag = def->getValueAsDag("parameters")) {
+    for (unsigned i = 0, e = parametersDag->getNumArgs(); i < e; ++i)
+      parameters.push_back(AttrOrTypeParameter(parametersDag, i));
+  }
 }
 
 Dialect AttrOrTypeDef::getDialect() const {
   auto *dialect = dyn_cast<llvm::DefInit>(def->getValue("dialect")->getValue());
   return Dialect(dialect ? dialect->getDef() : nullptr);
 }
 
 StringRef AttrOrTypeDef::getName() const { return def->getName(); }

 
 bool AttrOrTypeDef::genStorageClass() const {
   return def->getValueAsBit("genStorageClass");
 }
 
 bool AttrOrTypeDef::hasStorageCustomConstructor() const {
   return def->getValueAsBit("hasStorageCustomConstructor");
 }
 
-void AttrOrTypeDef::getParameters(
-    SmallVectorImpl<AttrOrTypeParameter> &parameters) const {
-  if (auto *parametersDag = def->getValueAsDag("parameters")) {
-    for (unsigned i = 0, e = parametersDag->getNumArgs(); i < e; ++i)
-      parameters.push_back(AttrOrTypeParameter(parametersDag, i));
-  }
-}
-
 unsigned AttrOrTypeDef::getNumParameters() const {
   auto *parametersDag = def->getValueAsDag("parameters");
   return parametersDag ? parametersDag->getNumArgs() : 0;
 }
 
 Optional<StringRef> AttrOrTypeDef::getMnemonic() const {
   return def->getValueAsOptionalString("mnemonic");
 }
 

mlir/lib/TableGen/Class.cpp

 //===- Class.cpp - Helper classes for Op C++ code emission --------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "mlir/TableGen/Class.h"
-
 #include "mlir/TableGen/Format.h"
 #include "llvm/ADT/Sequence.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include <unordered_set>
-
-#define DEBUG_TYPE "mlir-tblgen-opclass"
 
 using namespace mlir;
 using namespace mlir::tblgen;
 
-// Returns space to be emitted after the given C++ `type`. return "" if the
-// ends with '&' or '*', or is empty, else returns " ".
+/// Returns space to be emitted after the given C++ `type`. return "" if the
+/// ends with '&' or '*', or is empty, else returns " ".
 static StringRef getSpaceAfterType(StringRef type) {
   return (type.empty() || type.endswith("&") || type.endswith("*")) ? "" : " ";
 }
 
 //===----------------------------------------------------------------------===//
 // MethodParameter definitions
 //===----------------------------------------------------------------------===//
 
-void MethodParameter::writeTo(raw_ostream &os, bool emitDefault) const {
+void MethodParameter::writeDeclTo(raw_indented_ostream &os) const {
   if (optional)
     os << "/*optional*/";
   os << type << getSpaceAfterType(type) << name;
-  if (emitDefault && hasDefaultValue())
+  if (hasDefaultValue())
     os << " = " << defaultValue;
 }
 
+void MethodParameter::writeDefTo(raw_indented_ostream &os) const {
+  if (optional)
+    os << "/*optional*/";
+  os << type << getSpaceAfterType(type) << name;
+}
+
 //===----------------------------------------------------------------------===//
 // MethodParameters definitions
 //===----------------------------------------------------------------------===//
 
-void MethodParameters::writeDeclTo(raw_ostream &os) const {
+void MethodParameters::writeDeclTo(raw_indented_ostream &os) const {
   llvm::interleaveComma(parameters, os,
                         [&os](auto &param) { param.writeDeclTo(os); });
 }
-void MethodParameters::writeDefTo(raw_ostream &os) const {
+void MethodParameters::writeDefTo(raw_indented_ostream &os) const {
   llvm::interleaveComma(parameters, os,
                         [&os](auto &param) { param.writeDefTo(os); });
 }
 
 bool MethodParameters::subsumes(const MethodParameters &other) const {
   // These parameters do not subsume the others if there are fewer parameters
   // or their types do not match.
   if (parameters.size() < other.parameters.size())

 // MethodSignature definitions
 //===----------------------------------------------------------------------===//
 
 bool MethodSignature::makesRedundant(const MethodSignature &other) const {
   return methodName == other.methodName &&
          parameters.subsumes(other.parameters);
 }
 
-void MethodSignature::writeDeclTo(raw_ostream &os) const {
+void MethodSignature::writeDeclTo(raw_indented_ostream &os) const {
   os << returnType << getSpaceAfterType(returnType) << methodName << "(";
   parameters.writeDeclTo(os);
   os << ")";
 }
 
-void MethodSignature::writeDefTo(raw_ostream &os, StringRef namePrefix) const {
+void MethodSignature::writeDefTo(raw_indented_ostream &os,
+                                 StringRef namePrefix) const {
   os << returnType << getSpaceAfterType(returnType) << namePrefix
      << (namePrefix.empty() ? "" : "::") << methodName << "(";
   parameters.writeDefTo(os);
   os << ")";
 }
 
 //===----------------------------------------------------------------------===//
 // MethodBody definitions
 //===----------------------------------------------------------------------===//
 
-MethodBody::MethodBody(bool declOnly) : isEffective(!declOnly) {}
-
-MethodBody &MethodBody::operator<<(Twine content) {
-  if (isEffective)
-    body.append(content.str());
-  return *this;
-}
-
-MethodBody &MethodBody::operator<<(int content) {
-  if (isEffective)
-    body.append(std::to_string(content));
-  return *this;
-}
+MethodBody::MethodBody(bool declOnly)
+    : declOnly(declOnly), stringOs(body), os(stringOs) {}
 
-MethodBody &MethodBody::operator<<(const FmtObjectBase &content) {
-  if (isEffective)
-    body.append(content.str());
-  return *this;
-}
-
-void MethodBody::writeTo(raw_ostream &os) const {
+void MethodBody::writeTo(raw_indented_ostream &os) const {
   auto bodyRef = StringRef(body).drop_while([](char c) { return c == '\n'; });
   os << bodyRef;
-  if (bodyRef.empty() || bodyRef.back() != '\n')
+  if (bodyRef.empty())
+    return;
+  if (bodyRef.back() != '\n')
     os << "\n";
 }
 
 //===----------------------------------------------------------------------===//
 // Method definitions
 //===----------------------------------------------------------------------===//
 
-void Method::writeDeclTo(raw_ostream &os) const {
-  os.indent(2);
+void Method::writeDeclTo(raw_indented_ostream &os) const {
   if (isStatic())
     os << "static ";
-  if ((properties & MP_Constexpr) == MP_Constexpr)
+  if (properties & ConstexprValue)
     os << "constexpr ";
   methodSignature.writeDeclTo(os);
+  if (isConst())
+    os << " const";
   if (!isInline()) {
-    os << ";";
-  } else {
-    os << " {\n";
-    methodBody.writeTo(os.indent(2));
-    os.indent(2) << "}";
+    os << ";\n\n";
+    return;
   }
+  os << " {\n";
+  methodBody.writeTo(os);
+  os << "}\n\n";
 }
 
-void Method::writeDefTo(raw_ostream &os, StringRef namePrefix) const {
-  // Do not write definition if the method is decl only.
-  if (properties & MP_Declaration)
-    return;
-  // Do not generate separate definition for inline method
-  if (isInline())
+void Method::writeDefTo(raw_indented_ostream &os, StringRef namePrefix) const {
+  // The method has no definition to write if it is declaration only or inline.
+  if (properties & Declaration || isInline())
     return;
+
   methodSignature.writeDefTo(os, namePrefix);
+  if (isConst())
+    os << " const";
   os << " {\n";
   methodBody.writeTo(os);
-  os << "}";
+  os << "}\n\n";
 }
 
 //===----------------------------------------------------------------------===//
 // Constructor definitions
 //===----------------------------------------------------------------------===//
 
-void Constructor::addMemberInitializer(StringRef name, StringRef value) {
-  memberInitializers.append(std::string(llvm::formatv(
-      "{0}{1}({2})", memberInitializers.empty() ? " : " : ", ", name, value)));
+void Constructor::writeDeclTo(raw_indented_ostream &os) const {
+  if (properties & ConstexprValue)
+    os << "constexpr ";
+  methodSignature.writeDeclTo(os);
+  if (!isInline()) {
+    os << ";\n\n";
+    return;
+  }
+  os << ' ';
+  if (!initializers.empty())
+    os << ": ";
+  llvm::interleaveComma(initializers, os,
+                        [&](auto &initializer) { initializer.writeTo(os); });
+  if (!initializers.empty())
+    os << ' ';
+  os << "{";
+  methodBody.writeTo(os);
+  os << "}\n\n";
 }
 
-void Constructor::writeDefTo(raw_ostream &os, StringRef namePrefix) const {
-  // Do not write definition if the method is decl only.
-  if (properties & MP_Declaration)
+void Constructor::writeDefTo(raw_indented_ostream &os,
+                             StringRef namePrefix) const {
+  // The method has no definition to write if it is declaration only or inline.
+  if (properties & Declaration || isInline())
     return;
 
   methodSignature.writeDefTo(os, namePrefix);
-  os << " " << memberInitializers << " {\n";
+  os << ' ';
+  if (!initializers.empty())
+    os << ": ";
+  llvm::interleaveComma(initializers, os,
+                        [&](auto &initializer) { initializer.writeTo(os); });
+  if (!initializers.empty())
+    os << ' ';
+  os << "{";
   methodBody.writeTo(os);
-  os << "}\n";
+  os << "}\n\n";
+}
+
+void Constructor::MemberInitializer::writeTo(raw_indented_ostream &os) const {
+  os << name << '(' << value << ')';
 }
 
 //===----------------------------------------------------------------------===//
-// Class definitions
+// Visibility definitions
 //===----------------------------------------------------------------------===//
 
-Class::Class(StringRef name) : className(name) {}
-
-void Class::newField(StringRef type, StringRef name, StringRef defaultValue) {
-  std::string varName = formatv("{0} {1}", type, name).str();
-  std::string field = defaultValue.empty()
-                          ? varName
-                          : formatv("{0} = {1}", varName, defaultValue).str();
-  fields.push_back(std::move(field));
-}
-
-void Class::writeDeclTo(raw_ostream &os) const {
-  bool hasPrivateMethod = false;
-  os << "class " << className << " {\n";
-  os << "public:\n";
-
-  forAllMethods([&](const Method &method) {
-    if (!method.isPrivate()) {
-      method.writeDeclTo(os);
-      os << '\n';
-    } else {
-      hasPrivateMethod = true;
-    }
-  });
+namespace mlir {
+namespace tblgen {
+raw_ostream &operator<<(raw_ostream &os, Visibility visibility) {
+  switch (visibility) {
+  case Visibility::Public:
+    return os << "public";
+  case Visibility::Protected:
+    return os << "protected";
+  case Visibility::Private:
+    return os << "private";
+  return os;
+}
+} // end namespace tblgen
+} // end namespace mlir
 
-  os << '\n';
-  os << "private:\n";
-  if (hasPrivateMethod) {
-    forAllMethods([&](const Method &method) {
-      if (method.isPrivate()) {
-        method.writeDeclTo(os);
-        os << '\n';
-      }
-    });
-    os << '\n';
-  }
+//===----------------------------------------------------------------------===//
+// ParentClass definitions
+//===----------------------------------------------------------------------===//
+
+void ParentClass::writeTo(raw_indented_ostream &os) const {
+  os << visibility << ' ' << name;
+  if (!templateParams.empty()) {
+    auto scope = os.scope("<", ">", /*indent=*/false);
+    llvm::interleaveComma(templateParams, os,
+                          [&](auto &param) { os << param; });
 
-  for (const auto &field : fields)
-    os.indent(2) << field << ";\n";
-  os << "};\n";
-}
+//===----------------------------------------------------------------------===//
+// UsingDeclaration definitions
+//===----------------------------------------------------------------------===//
 
-void Class::writeDefTo(raw_ostream &os) const {
-  forAllMethods([&](const Method &method) {
-    method.writeDefTo(os, className);
-    os << "\n";
-  });
+void UsingDeclaration::writeDeclTo(raw_indented_ostream &os) const {
+  os << "using " << name;
+  if (!value.empty())
+    os << " = " << value;
+  os << ";\n";
 }
 
-// Insert a new method into a list of methods, if it would not be pruned, and
-// prune and existing methods.
-template <typename ContainerT, typename MethodT>
-MethodT *insertAndPrune(ContainerT &methods, MethodT newMethod) {
-  if (llvm::any_of(methods, [&](auto &method) {
-        return method.makesRedundant(newMethod);
-      }))
-    return nullptr;
+//===----------------------------------------------------------------------===//
+// Field definitions
+//===----------------------------------------------------------------------===//
 
-  llvm::erase_if(
-      methods, [&](auto &method) { return newMethod.makesRedundant(method); });
-  methods.push_back(std::move(newMethod));
-  return &methods.back();
+void Field::writeDeclTo(raw_indented_ostream &os) const {
+  os << type << ' ' << name << ";\n";
 }
 
-Method *Class::addMethodAndPrune(Method &&newMethod) {
-  return insertAndPrune(methods, std::move(newMethod));
-}
+//===----------------------------------------------------------------------===//
+// VisibilityDeclaration definitions
+//===----------------------------------------------------------------------===//
 
-Constructor *Class::addConstructorAndPrune(Constructor &&newCtor) {
-  return insertAndPrune(constructors, std::move(newCtor));
+void VisibilityDeclaration::writeDeclTo(raw_indented_ostream &os) const {
+  os.unindent();
+  os << visibility << ":\n";
+  os.indent();
 }
 
 //===----------------------------------------------------------------------===//
-// OpClass definitions
+// ExtraClassDeclaration definitions
 //===----------------------------------------------------------------------===//
 
-OpClass::OpClass(StringRef name, StringRef extraClassDeclaration)
-    : Class(name), extraClassDeclaration(extraClassDeclaration) {}
-
-void OpClass::addTrait(Twine trait) { traits.insert(trait.str()); }
+void ExtraClassDeclaration::writeDeclTo(raw_indented_ostream &os) const {
+  os.printReindented(extraClassDeclaration);
+}
 
-void OpClass::writeDeclTo(raw_ostream &os) const {
-  os << "class " << className << " : public ::mlir::Op<" << className;
-  for (const auto &trait : traits)
-    os << ", " << trait;
-  os << "> {\npublic:\n"
-     << "  using Op::Op;\n"
-     << "  using Op::print;\n"
-     << "  using Adaptor = " << className << "Adaptor;\n";
+//===----------------------------------------------------------------------===//
+// Class definitions
+//===----------------------------------------------------------------------===//
 
-  bool hasPrivateMethod = false;
-  forAllMethods([&](const Method &method) {
-    if (!method.isPrivate()) {
-      method.writeDeclTo(os);
-      os << "\n";
-    } else {
-      hasPrivateMethod = true;
-    }
+ParentClass &Class::addParent(ParentClass parent) {
+  parents.push_back(std::move(parent));
+  return parents.back();
+}
+
+void Class::writeDeclTo(raw_indented_ostream &os) const {
+  // Declare the class.
+  os << (isStruct ? "struct" : "class") << ' ' << className << ' ';
+
+  // Declare the parent classes, if any.
+  if (!parents.empty()) {
+    os << ": ";
+    llvm::interleaveComma(parents, os,
+                          [&](auto &parent) { parent.writeTo(os); });
+    os << ' ';
+  }
+  auto classScope = os.scope("{\n", "};\n", /*indent=*/true);
+
+  // Print all the class declarations.
+  for (auto &decl : declarations)
+    decl->writeDeclTo(os);
+}
+
+void Class::writeDefTo(raw_indented_ostream &os) const {
+  // Print all the definitions.
+  for (auto &decl : declarations)
+    decl->writeDefTo(os, className);
+}
+
+void Class::finalize() {
+  // Sort the methods by public and private. Remove them from the pending list
+  // of methods.
+  SmallVector<std::unique_ptr<Method>> publicMethods, privateMethods;
+  for (auto &method : methods) {
+    if (method->isPrivate())
+      privateMethods.push_back(std::move(method));
+    else
+      publicMethods.push_back(std::move(method));
+  }
+  methods.clear();
+
+  // If the last visibility declaration wasn't `public`, add one that is. Then,
+  // declare the public methods.
+  if (!publicMethods.empty() && getLastVisibilityDecl() != Visibility::Public)
+    declare<VisibilityDeclaration>(Visibility::Public);
+  for (auto &method : publicMethods)
+    declarations.push_back(std::move(method));
+
+  // If the last visibility declaration wasn't `private`, add one that is. Then,
+  // declare the private methods.
+  if (!privateMethods.empty() && getLastVisibilityDecl() != Visibility::Private)
+    declare<VisibilityDeclaration>(Visibility::Private);
+  for (auto &method : privateMethods)
+    declarations.push_back(std::move(method));
+
+  // All fields added to the pending list are private and declared at the bottom
+  // of the class. If the last visibility declaration wasn't `private`, add one
+  // that is, then declare the fields.
+  if (!fields.empty() && getLastVisibilityDecl() != Visibility::Private)
+    declare<VisibilityDeclaration>(Visibility::Private);
+  for (auto &field : fields)
+    declare<Field>(std::move(field));
+  fields.clear();
+}
+
+Visibility Class::getLastVisibilityDecl() const {
+  auto reverseDecls = llvm::reverse(declarations);
+  auto it = llvm::find_if(reverseDecls, [](auto &decl) {
+    return isa<VisibilityDeclaration>(decl);
   });
-
-  // TODO: Add line control markers to make errors easier to debug.
-  if (!extraClassDeclaration.empty())
-    os << extraClassDeclaration << "\n";
-
-  if (hasPrivateMethod) {
-    os << "\nprivate:\n";
-    forAllMethods([&](const Method &method) {
-      if (method.isPrivate()) {
-        method.writeDeclTo(os);
-        os << "\n";
-      }
-    });
-  }
+  return it == reverseDecls.end()
+             ? (isStruct ? Visibility::Public : Visibility::Private)
+             : cast<VisibilityDeclaration>(*it).getVisibility();
+
+Method *insertAndPruneMethods(std::vector<std::unique_ptr<Method>> &methods,
+                              std::unique_ptr<Method> newMethod) {
+  if (llvm::any_of(methods, [&](auto &method) {
+        return method->makesRedundant(*newMethod);
+      }))
+    return nullptr;
+
+  llvm::erase_if(methods, [&](auto &method) {
+    return newMethod->makesRedundant(*method);
+  methods.push_back(std::move(newMethod));
+  return methods.back().get();
 
-  os << "};\n";
+Method *Class::addMethodAndPrune(Method &&newMethod) {
+  return insertAndPruneMethods(methods,
+                               std::make_unique<Method>(std::move(newMethod)));
+}
+
+Constructor *Class::addConstructorAndPrune(Constructor &&newCtor) {
+  return dyn_cast_or_null<Constructor>(insertAndPruneMethods(
+      methods, std::make_unique<Constructor>(std::move(newCtor))));
 }

mlir/lib/TableGen/Format.cpp

 #include <cctype>
 
 using namespace mlir;
 using namespace mlir::tblgen;
 
 // Marker to indicate an error happened when replacing a placeholder.
 const char *const kMarkerForNoSubst = "<no-subst-found>";
 
-FmtContext &FmtContext::addSubst(StringRef placeholder, Twine subst) {
+FmtContext::FmtContext(ArrayRef<std::pair<StringRef, StringRef>> subs) {
+  for (auto &sub : subs)
+    addSubst(sub.first, sub.second);
+}
+
+FmtContext &FmtContext::addSubst(StringRef placeholder, const Twine &subst) {
   customSubstMap[placeholder] = subst.str();
   return *this;
 }
 
 FmtContext &FmtContext::withBuilder(Twine subst) {
   builtinSubstMap[PHKind::Builder] = subst.str();
   return *this;
 }

mlir/test/mlir-tblgen/attr-or-type-format.td

 def TypeParamB : TypeParameter<"TestParamD", "a type param D"> {
   let parser = "someFcnCall()";
   let printer = "myPrinter($_self)";
 }
 
 /// Check simple attribute parser and printer are generated correctly.
 
 // ATTR: ::mlir::Attribute TestAAttr::parse(::mlir::AsmParser &parser,
-// ATTR:                                    ::mlir::Type attrType) {
+// ATTR:                                    ::mlir::Type type) {
 // ATTR:   FailureOr<IntegerAttr> _result_value;
 // ATTR:   FailureOr<TestParamA> _result_complex;
 // ATTR:   if (parser.parseKeyword("hello"))
 // ATTR:     return {};
 // ATTR:   if (parser.parseEqual())
 // ATTR:     return {};
 // ATTR:   _result_value = ::mlir::FieldParser<IntegerAttr>::parse(parser);
 // ATTR:   if (failed(_result_value))
 // ATTR:     return {};
 // ATTR:   if (parser.parseComma())
 // ATTR:     return {};
-// ATTR:   _result_complex = ::parseAttrParamA(parser, attrType);
+// ATTR:   _result_complex = ::parseAttrParamA(parser, type);
 // ATTR:   if (failed(_result_complex))
 // ATTR:     return {};
 // ATTR:   if (parser.parseRParen())
 // ATTR:     return {};
 // ATTR:   return TestAAttr::get(parser.getContext(),
 // ATTR:                         _result_value.getValue(),
 // ATTR:                         _result_complex.getValue());
 // ATTR: }
def AttrA : TestAttr<"TestA"> {
 
   let mnemonic = "attr_a";
   let assemblyFormat = "`hello` `=` $value `,` $complex `)`";
 }
 
 /// Test simple struct parser and printer are generated correctly.
 
 // ATTR: ::mlir::Attribute TestBAttr::parse(::mlir::AsmParser &parser,
-// ATTR:                                    ::mlir::Type attrType) {
+// ATTR:                                    ::mlir::Type type) {
 // ATTR:   bool _seen_v0 = false;
 // ATTR:   bool _seen_v1 = false;
 // ATTR:   for (unsigned _index = 0; _index < 2; ++_index) {
 // ATTR:     StringRef _paramKey;
 // ATTR:     if (parser.parseKeyword(&_paramKey))
 // ATTR:       return {};
 // ATTR:     if (parser.parseEqual())
 // ATTR:       return {};
 // ATTR:     if (!_seen_v0 && _paramKey == "v0") {
 // ATTR:       _seen_v0 = true;
-// ATTR:       _result_v0 = ::parseAttrParamA(parser, attrType);
+// ATTR:       _result_v0 = ::parseAttrParamA(parser, type);
 // ATTR:       if (failed(_result_v0))
 // ATTR:         return {};
 // ATTR:     } else if (!_seen_v1 && _paramKey == "v1") {
 // ATTR:       _seen_v1 = true;
-// ATTR:       _result_v1 = attrType ? ::parseAttrWithType(parser, attrType) : ::parseAttrWithout(parser);
+// ATTR:       _result_v1 = type ? ::parseAttrWithType(parser, type) : ::parseAttrWithout(parser);
 // ATTR:       if (failed(_result_v1))
 // ATTR:         return {};
 // ATTR:     } else {
 // ATTR:       return {};
 // ATTR:     }
 // ATTR:     if ((_index != 2 - 1) && parser.parseComma())
 // ATTR:       return {};
 // ATTR:   }
def AttrB : TestAttr<"TestB"> {
 
   let mnemonic = "attr_b";
   let assemblyFormat = "`{` struct($v0, $v1) `}`";
 }
 
 /// Test attribute with capture-all params has correct parser and printer.
 
 // ATTR: ::mlir::Attribute TestFAttr::parse(::mlir::AsmParser &parser,
-// ATTR:                                    ::mlir::Type attrType) {
+// ATTR:                                    ::mlir::Type type) {
 // ATTR:   ::mlir::FailureOr<int> _result_v0;
 // ATTR:   ::mlir::FailureOr<int> _result_v1;
 // ATTR:   _result_v0 = ::mlir::FieldParser<int>::parse(parser);
 // ATTR:   if (failed(_result_v0))
 // ATTR:     return {};
 // ATTR:   if (parser.parseComma())
 // ATTR:     return {};
 // ATTR:   _result_v1 = ::mlir::FieldParser<int>::parse(parser);

mlir/test/mlir-tblgen/attrdefs.td

 // RUN: mlir-tblgen -gen-attrdef-decls -I %S/../../include %s | FileCheck %s --check-prefix=DECL
 // RUN: mlir-tblgen -gen-attrdef-defs -I %S/../../include %s | FileCheck %s --check-prefix=DEF
 
 include "mlir/IR/OpBase.td"
 
 // DECL: #ifdef GET_ATTRDEF_CLASSES
 // DECL: #undef GET_ATTRDEF_CLASSES
 
 // DECL: namespace mlir {
-// DECL: class DialectAsmParser;
-// DECL: class DialectAsmPrinter;
-// DECL: } // namespace mlir
+// DECL: class AsmParser;
+// DECL: class AsmPrinter;
+// DECL: } // end namespace mlir
 
 // DEF: #ifdef GET_ATTRDEF_LIST
 // DEF: #undef GET_ATTRDEF_LIST
 // DEF: ::test::SimpleAAttr,
 // DEF: ::test::CompoundAAttr,
 // DEF: ::test::IndexAttr,
 // DEF: ::test::SingleParameterAttr
 
 // DEF-LABEL: ::mlir::OptionalParseResult generatedAttributeParser(
-// DEF-NEXT: ::mlir::AsmParser &parser,
-// DEF-NEXT: ::llvm::StringRef mnemonic, ::mlir::Type type,
-// DEF-NEXT: ::mlir::Attribute &value) {
+// DEF-SAME: ::mlir::AsmParser &parser,
+// DEF-SAME: ::llvm::StringRef mnemonic, ::mlir::Type type,
+// DEF-SAME: ::mlir::Attribute &value) {
 // DEF: if (mnemonic == ::test::CompoundAAttr::getMnemonic()) {
 // DEF-NEXT: value = ::test::CompoundAAttr::parse(parser, type);
 // DEF-NEXT: return ::mlir::success(!!value);
 // DEF-NEXT: }
 // DEF-NEXT: if (mnemonic == ::test::IndexAttr::getMnemonic()) {
 // DEF-NEXT:   value = ::test::IndexAttr::parse(parser, type);
 // DEF-NEXT:   return ::mlir::success(!!value);
 // DEF: return {};
let parameters = (
       APFloatParameter<"">: $apFloat,
       ArrayRefParameter<"int", "Matrix dimensions">:$dims,
       AttributeSelfTypeParameter<"">:$inner
   );
 
   let genVerifyDecl = 1;
 
 // DECL-LABEL: class CompoundAAttr : public ::mlir::Attribute
-// DECL: static CompoundAAttr getChecked(llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::test::SimpleTypeA exampleTdType, ::llvm::APFloat apFloat, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
+// DECL: static CompoundAAttr getChecked(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::test::SimpleTypeA exampleTdType, ::llvm::APFloat apFloat, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
 // DECL: static ::mlir::LogicalResult verify(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, int widthOfSomething, ::test::SimpleTypeA exampleTdType, ::llvm::APFloat apFloat, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
 // DECL: static constexpr ::llvm::StringLiteral getMnemonic() {
-// DECL:   return ::llvm::StringLiteral("cmpnd_a");
+// DECL:   return "cmpnd_a";
 // DECL: }
 // DECL: static ::mlir::Attribute parse(
 // DECL-SAME: ::mlir::AsmParser &parser, ::mlir::Type type);
 // DECL: void print(::mlir::AsmPrinter &printer) const;
 // DECL: int getWidthOfSomething() const;
 // DECL: ::test::SimpleTypeA getExampleTdType() const;
 // DECL: ::llvm::APFloat getApFloat() const;
 
 // Check that AttributeSelfTypeParameter is handled properly.
 // DEF-LABEL: struct CompoundAAttrStorage
-// DEF: CompoundAAttrStorage (
-// DEF-NEXT: : ::mlir::AttributeStorage(inner),
+// DEF: CompoundAAttrStorage(
+// DEF-SAME: : ::mlir::AttributeStorage(inner),
 
 // DEF: bool operator==(const KeyTy &tblgenKey) const {
-// DEF-NEXT: if (!(widthOfSomething == std::get<0>(tblgenKey)))
-// DEF-NEXT:   return false;
-// DEF-NEXT: if (!(exampleTdType == std::get<1>(tblgenKey)))
-// DEF-NEXT:   return false;
-// DEF-NEXT: if (!(apFloat.bitwiseIsEqual(std::get<2>(tblgenKey))))
-// DEF-NEXT:   return false;
-// DEF-NEXT: if (!(dims == std::get<3>(tblgenKey)))
-// DEF-NEXT:   return false;
-// DEF-NEXT: if (!(getType() == std::get<4>(tblgenKey)))
-// DEF-NEXT:   return false;
-// DEF-NEXT: return true;
+// DEF-NEXT: return
+// DEF-SAME: (widthOfSomething == std::get<0>(tblgenKey)) &&
+// DEF-SAME: (exampleTdType == std::get<1>(tblgenKey)) &&
+// DEF-SAME: (apFloat.bitwiseIsEqual(std::get<2>(tblgenKey))) &&
+// DEF-SAME: (dims == std::get<3>(tblgenKey)) &&
+// DEF-SAME: (getType() == std::get<4>(tblgenKey));
 
 // DEF: static CompoundAAttrStorage *construct
 // DEF: return new (allocator.allocate<CompoundAAttrStorage>())
-// DEF-NEXT: CompoundAAttrStorage(widthOfSomething, exampleTdType, apFloat, dims, inner);
+// DEF-SAME: CompoundAAttrStorage(widthOfSomething, exampleTdType, apFloat, dims, inner);
 
-// DEF: ::mlir::Type CompoundAAttr::getInner() const { return getImpl()->getType().cast<::mlir::Type>(); }
+// DEF: ::mlir::Type CompoundAAttr::getInner() const {
+// DEF-NEXT: return getImpl()->getType().cast<::mlir::Type>();
 }
 
 def C_IndexAttr : TestAttr<"Index"> {
     let mnemonic = "index";
 
     let parameters = (
       ins
       StringRefParameter<"Label for index">:$label
     );
 
 // DECL-LABEL: class IndexAttr : public ::mlir::Attribute
 // DECL: static constexpr ::llvm::StringLiteral getMnemonic() {
-// DECL:   return ::llvm::StringLiteral("index");
+// DECL:   return "index";
 // DECL: }
 // DECL: static ::mlir::Attribute parse(
 // DECL-SAME: ::mlir::AsmParser &parser, ::mlir::Type type);
 // DECL: void print(::mlir::AsmPrinter &printer) const;
 }
 
 def D_SingleParameterAttr : TestAttr<"SingleParameter"> {
   let parameters = (
     ins
     "int": $num
   );
 // DECL-LABEL: struct SingleParameterAttrStorage;
 // DECL-LABEL: class SingleParameterAttr
-// DECL-NEXT:                   detail::SingleParameterAttrStorage
+// DECL-SAME:  detail::SingleParameterAttrStorage
 }
 
 // An attribute testing AttributeSelfTypeParameter.
 def E_AttrWithTypeBuilder : TestAttr<"AttrWithTypeBuilder"> {
   let mnemonic = "attr_with_type_builder";
   let parameters = (ins "::mlir::IntegerAttr":$attr);
   let typeBuilder = "$_attr.getType()";
 }
 
 // DEF-LABEL: struct AttrWithTypeBuilderAttrStorage
-// DEF: AttrWithTypeBuilderAttrStorage (::mlir::IntegerAttr attr)
-// DEF-NEXT: : ::mlir::AttributeStorage(attr.getType()), attr(attr)
+// DEF: AttrWithTypeBuilderAttrStorage(::mlir::IntegerAttr attr)
+// DEF-SAME: : ::mlir::AttributeStorage(attr.getType()), attr(attr)
 
 def F_ParamWithAccessorTypeAttr : TestAttr<"ParamWithAccessorType"> {
   let parameters = (ins AttrParameter<"std::string", "", "StringRef">:$param);
 }
 
 // DECL-LABEL: class ParamWithAccessorTypeAttr
 // DECL: StringRef getParam()
 // DEF: ParamWithAccessorTypeAttrStorage
-// DEF-NEXT: ParamWithAccessorTypeAttrStorage (std::string param)
+// DEF: ParamWithAccessorTypeAttrStorage(std::string param)
 // DEF: StringRef ParamWithAccessorTypeAttr::getParam()
-

mlir/test/mlir-tblgen/typedefs.td

 // RUN: mlir-tblgen -gen-typedef-decls -I %S/../../include %s | FileCheck %s --check-prefix=DECL
 // RUN: mlir-tblgen -gen-typedef-defs -I %S/../../include %s | FileCheck %s --check-prefix=DEF
 
 include "mlir/IR/OpBase.td"
 
 // DECL: #ifdef GET_TYPEDEF_CLASSES
 // DECL: #undef GET_TYPEDEF_CLASSES
 
 // DECL: namespace mlir {
 // DECL: class AsmParser;
 // DECL: class AsmPrinter;
-// DECL: } // namespace mlir
+// DECL: } // end namespace mlir
 
 // DEF: #ifdef GET_TYPEDEF_LIST
 // DEF: #undef GET_TYPEDEF_LIST
 // DEF: ::test::SimpleAType,
 // DEF: ::test::CompoundAType,
 // DEF: ::test::IndexType,
 // DEF: ::test::SingleParameterType,
 // DEF: ::test::IntegerType
 
 // DEF-LABEL: ::mlir::OptionalParseResult generatedTypeParser(
-// DEF-NEXT: ::mlir::AsmParser &parser,
-// DEF-NEXT: ::llvm::StringRef mnemonic,
-// DEF-NEXT: ::mlir::Type &value) {
+// DEF-SAME: ::mlir::AsmParser &parser,
+// DEF-SAME: ::llvm::StringRef mnemonic,
+// DEF-SAME: ::mlir::Type &value) {
 // DEF: if (mnemonic == ::test::CompoundAType::getMnemonic()) {
 // DEF-NEXT:   value = ::test::CompoundAType::parse(parser);
 // DEF-NEXT:   return ::mlir::success(!!value);
 // DEF-NEXT: }
 // DEF-NEXT: if (mnemonic == ::test::IndexType::getMnemonic()) {
 // DEF-NEXT:   value = ::test::IndexType::parse(parser);
 // DEF-NEXT:   return ::mlir::success(!!value);
 // DEF: return {};
let parameters = (
       "SomeCppStruct": $exampleCppType,
       ArrayRefParameter<"int", "Matrix dimensions">:$dims,
       RTLValueType:$inner
   );
 
   let genVerifyDecl = 1;
 
 // DECL-LABEL: class CompoundAType : public ::mlir::Type
-// DECL: static CompoundAType getChecked(llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::test::SimpleTypeA exampleTdType, SomeCppStruct exampleCppType, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
+// DECL: static CompoundAType getChecked(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, ::mlir::MLIRContext *context, int widthOfSomething, ::test::SimpleTypeA exampleTdType, SomeCppStruct exampleCppType, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
 // DECL: static ::mlir::LogicalResult verify(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, int widthOfSomething, ::test::SimpleTypeA exampleTdType, SomeCppStruct exampleCppType, ::llvm::ArrayRef<int> dims, ::mlir::Type inner);
 // DECL: static constexpr ::llvm::StringLiteral getMnemonic() {
-// DECL:   return ::llvm::StringLiteral("cmpnd_a");
+// DECL:   return "cmpnd_a";
 // DECL: }
 // DECL: static ::mlir::Type parse(::mlir::AsmParser &parser);
 // DECL: void print(::mlir::AsmPrinter &printer) const;
 // DECL: int getWidthOfSomething() const;
 // DECL: ::test::SimpleTypeA getExampleTdType() const;
 // DECL: SomeCppStruct getExampleCppType() const;
 }
 
 def C_IndexType : TestType<"Index"> {
     let mnemonic = "index";
 
     let parameters = (
       ins
       StringRefParameter<"Label for index">:$label
     );
 
 // DECL-LABEL: class IndexType : public ::mlir::Type
 // DECL: static constexpr ::llvm::StringLiteral getMnemonic() {
-// DECL:   return ::llvm::StringLiteral("index");
+// DECL:   return "index";
 // DECL: }
 // DECL: static ::mlir::Type parse(::mlir::AsmParser &parser);
 // DECL: void print(::mlir::AsmPrinter &printer) const;
 }
 
 def D_SingleParameterType : TestType<"SingleParameter"> {
   let parameters = (
     ins
     "int": $num
   );
 // DECL-LABEL: struct SingleParameterTypeStorage;
 // DECL-LABEL: class SingleParameterType
-// DECL-NEXT:                   detail::SingleParameterTypeStorage
+// DECL-SAME:  detail::SingleParameterTypeStorage
 }
 
 def E_IntegerType : TestType<"Integer"> {
     let mnemonic = "int";
     let genVerifyDecl = 1;
     let parameters = (
         ins
         "SignednessSemantics":$signedness,

mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp

 //===- AttrOrTypeDefGen.cpp - MLIR AttrOrType definitions generator -------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "AttrOrTypeFormatGen.h"
 #include "mlir/Support/LogicalResult.h"
 #include "mlir/TableGen/AttrOrTypeDef.h"
+#include "mlir/TableGen/Class.h"
 #include "mlir/TableGen/CodeGenHelpers.h"
 #include "mlir/TableGen/Format.h"
 #include "mlir/TableGen/GenInfo.h"
 #include "mlir/TableGen/Interfaces.h"
 #include "llvm/ADT/Sequence.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/TableGen/Error.h"
 #include "llvm/TableGen/TableGenBackend.h"
 
 #define DEBUG_TYPE "mlir-tblgen-attrortypedefgen"
 

 
 /// Find all the AttrOrTypeDef for the specified dialect. If no dialect
 /// specified and can only find one dialect's defs, use that.
 static void collectAllDefs(StringRef selectedDialect,
                            std::vector<llvm::Record *> records,
                            SmallVectorImpl<AttrOrTypeDef> &resultDefs) {
   auto defs = llvm::map_range(
       records, [&](const llvm::Record *rec) { return AttrOrTypeDef(rec); });
-  if (defs.empty())
-    return;
-
-  StringRef dialectName;
   if (selectedDialect.empty()) {
-    if (defs.empty())
-      return;
-
-    Dialect dialect(nullptr);
-    for (const AttrOrTypeDef &typeDef : defs) {
-      if (!dialect) {
-        dialect = typeDef.getDialect();
-      } else if (dialect != typeDef.getDialect()) {
-        llvm::PrintFatalError("defs belonging to more than one dialect. Must "
-                              "select one via '--(attr|type)defs-dialect'");
-      }
-    }
-
-    dialectName = dialect.getName();
+    if (!llvm::is_splat(
+            llvm::map_range(defs, [](auto def) { return def.getDialect(); }))) {
+    resultDefs.assign(defs.begin(), defs.end());
   } else {
-    dialectName = selectedDialect;
+    auto dialectDefs = llvm::make_filter_range(defs, [&](auto def) {
+      return def.getDialect().getName().equals(selectedDialect);
+    });
+    resultDefs.assign(dialectDefs.begin(), dialectDefs.end());
   }
-
-  for (const AttrOrTypeDef &def : defs)
-    if (def.getDialect().getName().equals(dialectName))
-      resultDefs.push_back(def);
 }
 
 //===----------------------------------------------------------------------===//
-// ParamCommaFormatter
+// DefGen
 //===----------------------------------------------------------------------===//
 
 namespace {
-
-/// Pass an instance of this class to llvm::formatv() to emit a comma separated
-/// list of parameters in the format by 'EmitFormat'.
-class ParamCommaFormatter : public llvm::detail::format_adapter {
+class DefGen {
 public:
-  /// Choose the output format
-  enum EmitFormat {
-    /// Emit "parameter1Type parameter1Name, parameter2Type parameter2Name,
-    /// [...]".
-    TypeNamePairs,
+  /// Create the attribute or type class.
+  DefGen(const AttrOrTypeDef &def);
 
-    /// Emit "parameter1(parameter1), parameter2(parameter2), [...]".
-    TypeNameInitializer,
+  void emitDecl(raw_ostream &os) const {
+    if (storageCls) {
+      NamespaceEmitter ns(os, def.getStorageNamespace());
+      os << "struct " << def.getStorageClassName() << ";\n";
+    }
+    defCls.writeDeclTo(os);
+  }
+  void emitDef(raw_ostream &os) const {
+    if (storageCls && def.genStorageClass()) {
+      NamespaceEmitter ns(os, def.getStorageNamespace());
+      storageCls->writeDeclTo(os); // everything is inline
+    }
+    defCls.writeDefTo(os);
+  }
 
-    /// Emit "param1Name, param2Name, [...]".
-    JustParams,
-  };
+private:
+  /// Add traits from the TableGen definition to the class.
+  void createParentWithTraits();
+  /// Emit top-level declarations: using declarations and any extra class
+  /// declarations.
+  void emitTopLevelDeclarations();
+  /// Emit attribute or type builders.
+  void emitBuilders();
+  /// Emit a verifier for the def.
+  void emitVerifier();
+  /// Emit parsers and printers.
+  void emitParserPrinter();
+  /// Emit parameter accessors, if required.
+  void emitAccessors();
+  /// Emit interface methods.
+  void emitInterfaceMethods();
+
+  //===--------------------------------------------------------------------===//
+  // Builder Emission
+
+  /// Emit the default builder `Attribute::get`
+  void emitDefaultBuilder();
+  /// Emit the checked builder `Attribute::getChecked`
+  void emitCheckedBuilder();
+  /// Emit a custom builder.
+  void emitCustomBuilder(const AttrOrTypeBuilder &builder);
+  /// Emit a checked custom builder.
+  void emitCheckedCustomBuilder(const AttrOrTypeBuilder &builder);
+
+  //===--------------------------------------------------------------------===//
+  // Parser and Printer Emission
+  void emitParserPrinterBody(MethodBody &parser, MethodBody &printer);
+
+  //===--------------------------------------------------------------------===//
+  // Interface Method Emission
+
+  /// Emit methods for a trait.
+  void emitTraitMethods(const InterfaceTrait &trait);
+  /// Emit a trait method.
+  void emitTraitMethod(const InterfaceMethod &method);
+
+  //===--------------------------------------------------------------------===//
+  // Storage Class Emission
+  void emitStorageClass();
+  /// Generate the storage class constructor.
+  void emitStorageConstructor();
+  /// Emit the key type `KeyTy`.
+  void emitKeyType();
+  /// Emit the equality comparison operator.
+  void emitEquals();
+  /// Emit the key hash function.
+  void emitHashKey();
+  /// Emit the function to construct the storage class.
+  void emitConstruct();
+
+  //===--------------------------------------------------------------------===//
+  // Utility Function Declarations
+
+  /// Get the method parameters for a def builder, where the first several
+  /// parameters may be different.
+  SmallVector<MethodParameter>
+  getBuilderParams(std::initializer_list<MethodParameter> prefix) const;
+
+  //===--------------------------------------------------------------------===//
+  // Class fields
+
+  /// The attribute or type definition.
+  const AttrOrTypeDef &def;
+  /// The list of attribute or type parameters.
+  ArrayRef<AttrOrTypeParameter> params;
+  /// The attribute or type class.
+  Class defCls;
+  /// An optional attribute or type storage class. The storage class will
+  /// exist if and only if the def has more than zero parameters.
+  Optional<Class> storageCls;
+
+  /// The C++ base value of the def, either "Attribute" or "Type".
+  StringRef valueType;
+  /// The prefix/suffix of the TableGen def name, either "Attr" or "Type".
+  StringRef defType;
+} // end anonymous namespace
 
-  ParamCommaFormatter(EmitFormat emitFormat,
-                      ArrayRef<AttrOrTypeParameter> params,
-                      bool prependComma = true)
-      : emitFormat(emitFormat), params(params), prependComma(prependComma) {}
-
-  /// llvm::formatv will call this function when using an instance as a
-  /// replacement value.
-  void format(raw_ostream &os, StringRef options) override {
-    if (!params.empty() && prependComma)
-      os << ", ";
-
-    switch (emitFormat) {
-    case EmitFormat::TypeNamePairs:
-      interleaveComma(params, os, [&](const AttrOrTypeParameter &p) {
-        emitTypeNamePair(p, os);
-      });
-      break;
-    case EmitFormat::TypeNameInitializer:
-      interleaveComma(params, os, [&](const AttrOrTypeParameter &p) {
-        emitTypeNameInitializer(p, os);
-      });
-      break;
-    case EmitFormat::JustParams:
-      interleaveComma(params, os,
-                      [&](const AttrOrTypeParameter &p) { os << p.getName(); });
-      break;
-    }
-  }
+DefGen::DefGen(const AttrOrTypeDef &def)
+    : def(def), params(def.getParameters()), defCls(def.getCppClassName()),
+      valueType(isa<AttrDef>(def) ? "Attribute" : "Type"),
+      defType(isa<AttrDef>(def) ? "Attr" : "Type") {
+  // If a storage class is needed, create one.
+  if (def.getNumParameters() > 0)
+    storageCls.emplace(def.getStorageClassName(), /*isStruct=*/true);
+
+  // Create the parent class with any indicated traits.
+  createParentWithTraits();
+  // Emit top-level declarations.
+  emitTopLevelDeclarations();
+  // Emit builders for defs with parameters
+  if (storageCls)
+    emitBuilders();
+  // Emit the verifier.
+  if (storageCls && def.genVerifyDecl())
+    emitVerifier();
+  // Emit the mnemonic, if there is one, and any associated parser and printer.
+  if (def.getMnemonic())
+    emitParserPrinter();
+  // Emit accessors
+  if (def.genAccessors())
+    emitAccessors();
+  // Emit trait interface methods
+  emitInterfaceMethods();
+  defCls.finalize();
+  // Emit a storage class if one is needed
+  if (storageCls && def.genStorageClass())
+    emitStorageClass();
+}
+
+void DefGen::createParentWithTraits() {
+  ParentClass defParent(strfmt("::mlir::{0}::{1}Base", valueType, defType));
+  defParent.addTemplateParam(def.getCppClassName());
+  defParent.addTemplateParam(def.getCppBaseClassName());
+  defParent.addTemplateParam(storageCls
+                                 ? strfmt("{0}::{1}", def.getStorageNamespace(),
+                                          def.getStorageClassName())
+                                 : strfmt("::mlir::{0}Storage", valueType));
+  for (auto &trait : def.getTraits()) {
+    defParent.addTemplateParam(
+        isa<NativeTrait>(&trait)
+            ? cast<NativeTrait>(&trait)->getFullyQualifiedTraitName()
+            : cast<InterfaceTrait>(&trait)->getFullyQualifiedTraitName());
+  }
+  defCls.addParent(std::move(defParent));
+}
+
+void DefGen::emitTopLevelDeclarations() {
+  // Inherit constructors from the attribute or type class.
+  defCls.declare<VisibilityDeclaration>(Visibility::Public);
+  defCls.declare<UsingDeclaration>("Base::Base");
+
+  // Emit the extra declarations first in case there's a definition in there.
+  if (Optional<StringRef> extraDecl = def.getExtraDecls())
+    defCls.declare<ExtraClassDeclaration>(*extraDecl);
+}
+
+void DefGen::emitBuilders() {
+  if (!def.skipDefaultBuilders()) {
+    emitDefaultBuilder();
+    if (def.genVerifyDecl())
+      emitCheckedBuilder();
+  }
+  for (auto &builder : def.getBuilders()) {
+    emitCustomBuilder(builder);
+    if (def.genVerifyDecl())
+      emitCheckedCustomBuilder(builder);
 
-private:
-  // Emit "paramType paramName".
-  static void emitTypeNamePair(const AttrOrTypeParameter &param,
-                               raw_ostream &os) {
-    os << param.getCppType() << " " << param.getName();
-  }
-  // Emit "paramName(paramName)"
-  void emitTypeNameInitializer(const AttrOrTypeParameter &param,
-                               raw_ostream &os) {
-    os << param.getName() << "(" << param.getName() << ")";
-  }
+void DefGen::emitVerifier() {
+  defCls.declare<UsingDeclaration>("Base::getChecked");
+  defCls.declareStaticMethod(
+      "::mlir::LogicalResult", "verify",
+      getBuilderParams({{"::llvm::function_ref<::mlir::InFlightDiagnostic()>",
+                         "emitError"}}));
 
-  EmitFormat emitFormat;
-  ArrayRef<AttrOrTypeParameter> params;
-  bool prependComma;
+void DefGen::emitParserPrinter() {
+  auto *mnemonic = defCls.addStaticMethod<Method::Constexpr>(
+      "::llvm::StringLiteral", "getMnemonic");
+  mnemonic->body().indent() << strfmt("return \"{0}\";", *def.getMnemonic());
+  // Declare the parser and printer, if needed.
+  if (!def.needsParserPrinter() && !def.hasGeneratedParser() &&
+      !def.hasGeneratedPrinter())
+    return;
+
+  // Declare the parser.
+  SmallVector<MethodParameter> parserParams;
+  parserParams.emplace_back("::mlir::AsmParser &", "parser");
+  if (isa<AttrDef>(&def))
+    parserParams.emplace_back("::mlir::Type", "type");
+  auto *parser = defCls.addMethod(
+      strfmt("::mlir::{0}", valueType), "parse",
+      def.hasGeneratedParser() ? Method::Static : Method::StaticDeclaration,
+      std::move(parserParams));
+  // Declare the printer.
+  auto props =
+      def.hasGeneratedPrinter() ? Method::Const : Method::ConstDeclaration;
+  Method *printer =
+      defCls.addMethod("void", "print", props,
+                       MethodParameter("::mlir::AsmPrinter &", "printer"));
+  // Emit the bodies.
+  emitParserPrinterBody(parser->body(), printer->body());
+}
+
+void DefGen::emitAccessors() {
+  for (auto &param : params) {
+    Method *m = defCls.addMethod(
+        param.getCppAccessorType(), getParameterAccessorName(param.getName()),
+        def.genStorageClass() ? Method::Const : Method::ConstDeclaration);
+    // Generate accessor definitions only if we also generate the storage
+    // class. Otherwise, let the user define the exact accessor definition.
+    if (!def.genStorageClass())
+      continue;
+    auto scope = m->body().indent().scope("return getImpl()->", ";");
+    if (isa<AttributeSelfTypeParameter>(param))
+      m->body() << formatv("getType().cast<{0}>()", param.getCppType());
+    else
+      m->body() << param.getName();
+  }
+}
+
+void DefGen::emitInterfaceMethods() {
+  for (auto &traitDef : def.getTraits())
+    if (auto *trait = dyn_cast<InterfaceTrait>(&traitDef))
+      if (trait->shouldDeclareMethods())
+        emitTraitMethods(*trait);
+}
+
+//===----------------------------------------------------------------------===//
+// Builder Emission
+
+SmallVector<MethodParameter>
+DefGen::getBuilderParams(std::initializer_list<MethodParameter> prefix) const {
+  SmallVector<MethodParameter> builderParams;
+  builderParams.append(prefix.begin(), prefix.end());
+  for (auto &param : params)
+    builderParams.emplace_back(param.getCppType(), param.getName());
+  return builderParams;
+}
+
+void DefGen::emitDefaultBuilder() {
+  Method *m = defCls.addStaticMethod(
+      def.getCppClassName(), "get",
+      getBuilderParams({{"::mlir::MLIRContext *", "context"}}));
+  MethodBody &body = m->body().indent();
+  auto scope = body.scope("return Base::get(context", ");");
+  llvm::for_each(params, [&](auto &param) { body << ", " << param.getName(); });
+}
+
+void DefGen::emitCheckedBuilder() {
+  Method *m = defCls.addStaticMethod(
+      def.getCppClassName(), "getChecked",
+      getBuilderParams(
+          {{"::llvm::function_ref<::mlir::InFlightDiagnostic()>", "emitError"},
+           {"::mlir::MLIRContext *", "context"}}));
+  MethodBody &body = m->body().indent();
+  auto scope = body.scope("return Base::getChecked(emitError, context", ");");
+  llvm::for_each(params, [&](auto &param) { body << ", " << param.getName(); });
+}
+
+static SmallVector<MethodParameter>
+getCustomBuilderParams(std::initializer_list<MethodParameter> prefix,
+                       const AttrOrTypeBuilder &builder) {
+  auto params = builder.getParameters();
+  SmallVector<MethodParameter> builderParams;
+  builderParams.append(prefix.begin(), prefix.end());
+  if (!builder.hasInferredContextParameter())
+    builderParams.emplace_back("::mlir::MLIRContext *", "context");
+  for (auto &param : params) {
+    builderParams.emplace_back(param.getCppType(), *param.getName(),
+                               param.getDefaultValue());
+  }
+  return builderParams;
+}
+
+void DefGen::emitCustomBuilder(const AttrOrTypeBuilder &builder) {
+  // Don't emit a body if there isn't one.
+  auto props = builder.getBody() ? Method::Static : Method::StaticDeclaration;
+  Method *m = defCls.addMethod(def.getCppClassName(), "get", props,
+                               getCustomBuilderParams({}, builder));
+  if (!builder.getBody())
+    return;
+
+  // Format the body and emit it.
+  FmtContext ctx;
+  ctx.addSubst("_get", "Base::get");
+  if (!builder.hasInferredContextParameter())
+    ctx.addSubst("_ctxt", "context");
+  std::string bodyStr = tgfmt(*builder.getBody(), &ctx);
+  m->body().indent().getStream().printReindented(bodyStr);
+}
+
+/// Replace all instances of 'from' to 'to' in `str` and return the new string.
+static std::string replaceInStr(std::string str, StringRef from, StringRef to) {
+  size_t pos = 0;
+  while ((pos = str.find(from.data(), pos, from.size())) != std::string::npos)
+    str.replace(pos, from.size(), to.data(), to.size());
+  return str;
+}
+
+void DefGen::emitCheckedCustomBuilder(const AttrOrTypeBuilder &builder) {
+  // Don't emit a body if there isn't one.
+  auto props = builder.getBody() ? Method::Static : Method::StaticDeclaration;
+  Method *m = defCls.addMethod(
+      def.getCppClassName(), "getChecked", props,
+      getCustomBuilderParams(
+          {{"::llvm::function_ref<::mlir::InFlightDiagnostic()>", "emitError"}},
+          builder));
+  if (!builder.getBody())
+    return;
+
+  // Format the body and emit it. Replace $_get(...) with
+  // Base::getChecked(emitError, ...)
+  FmtContext ctx;
+  if (!builder.hasInferredContextParameter())
+    ctx.addSubst("_ctxt", "context");
+  std::string bodyStr = replaceInStr(builder.getBody()->str(), "$_get(",
+                                     "Base::getChecked(emitError, ");
+  bodyStr = tgfmt(bodyStr, &ctx);
+  m->body().indent().getStream().printReindented(bodyStr);
+}
+
+//===----------------------------------------------------------------------===//
+// Parser and Printer Emission
+
+void DefGen::emitParserPrinterBody(MethodBody &parser, MethodBody &printer) {
+  Optional<StringRef> parserCode = def.getParserCode();
+  Optional<StringRef> printerCode = def.getPrinterCode();
+  Optional<StringRef> asmFormat = def.getAssemblyFormat();
+  // Verify the parser-printer specification first.
+  if (asmFormat && (parserCode || printerCode)) {
+    PrintFatalError(def.getLoc(),
+                    def.getName() + ": assembly format cannot be specified at "
+                                    "the same time as printer or parser code");
+  }
+  // Specified code cannot be empty.
+  if (parserCode && parserCode->empty())
+    PrintFatalError(def.getLoc(), def.getName() + ": parser cannot be empty");
+  if (printerCode && printerCode->empty())
+    PrintFatalError(def.getLoc(), def.getName() + ": printer cannot be empty");
+  // Assembly format requires accessors to be generated.
+  if (asmFormat && !def.genAccessors()) {
+    PrintFatalError(def.getLoc(),
+                    def.getName() +
+                        ": the generated printer from 'assemblyFormat' "
+                        "requires 'genAccessors' to be true");
+  }
+
+  // Generate the parser and printer bodies.
+  if (asmFormat)
+    return generateAttrOrTypeFormat(def, parser, printer);
+
+  FmtContext ctx = FmtContext(
+      {{"_parser", "parser"}, {"_printer", "printer"}, {"_type", "type"}});
+  if (parserCode) {
+    ctx.addSubst("_ctxt", "parser.getContext()");
+    parser.indent().getStream().printReindented(tgfmt(*parserCode, &ctx).str());
+  }
+  if (printerCode) {
+    ctx.addSubst("_ctxt", "printer.getContext()");
+    printer.indent().getStream().printReindented(
+        tgfmt(*printerCode, &ctx).str());
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Interface Method Emission
+
+void DefGen::emitTraitMethods(const InterfaceTrait &trait) {
+  // Get the set of methods that should always be declared.
+  auto alwaysDeclaredMethods = trait.getAlwaysDeclaredMethods();
+  StringSet<> alwaysDeclared;
+  alwaysDeclared.insert(alwaysDeclaredMethods.begin(),
+                        alwaysDeclaredMethods.end());
+
+  Interface iface = trait.getInterface(); // causes strange bugs if elided
+  for (auto &method : iface.getMethods()) {
+    // Don't declare if the method has a body. Or if the method has a default
+    // implementation and the def didn't request that it always be declared.
+    if (method.getBody() || (method.getDefaultImplementation() &&
+                             !alwaysDeclared.count(method.getName())))
+      continue;
+    emitTraitMethod(method);
+  }
+}
+
+void DefGen::emitTraitMethod(const InterfaceMethod &method) {
+  // All interface methods are declaration-only.
+  auto props =
+      method.isStatic() ? Method::StaticDeclaration : Method::ConstDeclaration;
+  SmallVector<MethodParameter> params;
+  for (auto &param : method.getArguments())
+    params.emplace_back(param.type, param.name);
+  defCls.addMethod(method.getReturnType(), method.getName(), props,
+                   std::move(params));
+}
+
+//===----------------------------------------------------------------------===//
+// Storage Class Emission
+
+void DefGen::emitStorageConstructor() {
+  Constructor *ctor =
+      storageCls->addConstructor<Method::Inline>(getBuilderParams({}));
+  if (auto *attrDef = dyn_cast<AttrDef>(&def)) {
+    // For attributes, a parameter marked with AttributeSelfTypeParameter is
+    // the type initializer that must be passed to the parent constructor.
+    const auto isSelfType = [](const AttrOrTypeParameter &param) {
+      return isa<AttributeSelfTypeParameter>(param);
     };
+    auto *selfTypeParam = llvm::find_if(params, isSelfType);
+    if (std::count_if(selfTypeParam, params.end(), isSelfType) > 1) {
+      PrintFatalError(def.getLoc(),
+                      "Only one attribute parameter can be marked as "
+                      "AttributeSelfTypeParameter");
+    }
+    // Alternatively, if a type builder was specified, use that instead.
+    std::string attrStorageInit =
+        selfTypeParam == params.end() ? "" : selfTypeParam->getName().str();
+    if (attrDef->getTypeBuilder()) {
+      FmtContext ctx;
+      for (auto &param : params)
+        ctx.addSubst(strfmt("_{0}", param.getName()), param.getName());
+      attrStorageInit = tgfmt(*attrDef->getTypeBuilder(), &ctx);
+    }
+    ctor->addMemberInitializer("::mlir::AttributeStorage",
+                               std::move(attrStorageInit));
+    // Initialize members that aren't the attribute's type.
+    for (auto &param : params)
+      if (selfTypeParam == params.end() || *selfTypeParam != param)
+        ctor->addMemberInitializer(param.getName(), param.getName());
+  } else {
+    for (auto &param : params)
+      ctor->addMemberInitializer(param.getName(), param.getName());
+  }
+}
 
-} // end anonymous namespace
+void DefGen::emitKeyType() {
+  std::string keyType("std::tuple<");
+  llvm::raw_string_ostream os(keyType);
+  llvm::interleaveComma(params, os,
+                        [&](auto &param) { os << param.getCppType(); });
+  os << '>';
+  storageCls->declare<UsingDeclaration>("KeyTy", std::move(os.str()));
+}
+
+void DefGen::emitEquals() {
+  Method *eq = storageCls->addConstMethod<Method::Inline>(
+      "bool", "operator==", MethodParameter("const KeyTy &", "tblgenKey"));
+  auto &body = eq->body().indent();
+  auto scope = body.scope("return (", ");");
+  const auto eachFn = [&](auto it) {
+    FmtContext ctx({{"_lhs", isa<AttributeSelfTypeParameter>(it.value())
+                                 ? "getType()"
+                                 : it.value().getName()},
+                    {"_rhs", strfmt("std::get<{0}>(tblgenKey)", it.index())}});
+    Optional<StringRef> comparator = it.value().getComparator();
+    body << tgfmt(comparator ? *comparator : "$_lhs == $_rhs", &ctx);
+  };
+  llvm::interleave(llvm::enumerate(params), body, eachFn, ") && (");
+}
+
+void DefGen::emitHashKey() {
+  Method *hash = storageCls->addStaticInlineMethod(
+      "::llvm::hash_code", "hashKey",
+      MethodParameter("const KeyTy &", "tblgenKey"));
+  auto &body = hash->body().indent();
+  auto scope = body.scope("return ::llvm::hash_combine(", ");");
+  llvm::interleaveComma(llvm::enumerate(params), body, [&](auto it) {
+    body << llvm::formatv("std::get<{0}>(tblgenKey)", it.index());
+  });
+}
+
+void DefGen::emitConstruct() {
+  Method *construct = storageCls->addMethod<Method::Inline>(
+      strfmt("{0} *", def.getStorageClassName()), "construct",
+      def.hasStorageCustomConstructor() ? Method::StaticDeclaration
+                                        : Method::Static,
+      MethodParameter(strfmt("::mlir::{0}StorageAllocator &", valueType),
+                      "allocator"),
+      MethodParameter("const KeyTy &", "tblgenKey"));
+  if (!def.hasStorageCustomConstructor()) {
+    auto &body = construct->body().indent();
+    for (auto it : llvm::enumerate(params)) {
+      body << formatv("auto {0} = std::get<{1}>(tblgenKey);\n",
+                      it.value().getName(), it.index());
+    }
+    // Use the parameters' custom allocator code, if provided.
+    FmtContext ctx = FmtContext().addSubst("_allocator", "allocator");
+    for (auto &param : params) {
+      if (Optional<StringRef> allocCode = param.getAllocator()) {
+        ctx.withSelf(param.getName()).addSubst("_dst", param.getName());
+        body << tgfmt(*allocCode, &ctx) << '\n';
+      }
+    }
+    auto scope =
+        body.scope(strfmt("return new (allocator.allocate<{0}>()) {0}(",
+                          def.getStorageClassName()),
+                   ");");
+    llvm::interleaveComma(params, body,
+                          [&](auto &param) { body << param.getName(); });
+  }
+}
+
+void DefGen::emitStorageClass() {
+  // Add the appropriate parent class.
+  storageCls->addParent(strfmt("::mlir::{0}Storage", valueType));
+  // Add the constructor.
+  emitStorageConstructor();
+  // Declare the key type.
+  emitKeyType();
+  // Add the comparison method.
+  emitEquals();
+  // Emit the key hash method.
+  emitHashKey();
+  // Emit the storage constructor. Just declare it if the user wants to define
+  // it themself.
+  emitConstruct();
+  // Emit the storage class members as public, at the very end of the struct.
+  storageCls->finalize();
+  for (auto &param : params)
+    if (!isa<AttributeSelfTypeParameter>(param))
+      storageCls->declare<Field>(param.getCppType(), param.getName());
+}
 
 //===----------------------------------------------------------------------===//
 // DefGenerator
 //===----------------------------------------------------------------------===//
 
 namespace {
 /// This struct is the base generator used when processing tablegen interfaces.
 class DefGenerator {
 public:
   bool emitDecls(StringRef selectedDialect);
   bool emitDefs(StringRef selectedDialect);
 
 protected:
-  DefGenerator(std::vector<llvm::Record *> &&defs, raw_ostream &os)
-      : defRecords(std::move(defs)), os(os), isAttrGenerator(false) {}
+  DefGenerator(std::vector<llvm::Record *> &&defs, raw_ostream &os,
+               StringRef defType, StringRef valueType, bool isAttrGenerator)
+      : defRecords(std::move(defs)), os(os), defType(defType),
+        valueType(valueType), isAttrGenerator(isAttrGenerator) {}
 
-  /// Emit the declaration of a single def.
-  void emitDefDecl(const AttrOrTypeDef &def);
   /// Emit the list of def type names.
   void emitTypeDefList(ArrayRef<AttrOrTypeDef> defs);
   /// Emit the code to dispatch between different defs during parsing/printing.
   void emitParsePrintDispatch(ArrayRef<AttrOrTypeDef> defs);
-  /// Emit the definition of a single def.
-  void emitDefDef(const AttrOrTypeDef &def);
-  /// Emit the storage class for the given def.
-  void emitStorageClass(const AttrOrTypeDef &def);
-  /// Emit the parser/printer for the given def.
-  void emitParsePrint(const AttrOrTypeDef &def);
 
   /// The set of def records to emit.
   std::vector<llvm::Record *> defRecords;
+  /// The attribute or type class to emit.
   /// The stream to emit to.
   raw_ostream &os;
   /// The prefix of the tablegen def name, e.g. Attr or Type.
-  StringRef defTypePrefix;
+  StringRef defType;
   /// The C++ base value type of the def, e.g. Attribute or Type.
   StringRef valueType;
   /// Flag indicating if this generator is for Attributes. False if the
   /// generator is for types.
   bool isAttrGenerator;
 };
 
 /// A specialized generator for AttrDefs.
 struct AttrDefGenerator : public DefGenerator {
   AttrDefGenerator(const llvm::RecordKeeper &records, raw_ostream &os)
-      : DefGenerator(records.getAllDerivedDefinitions("AttrDef"), os) {
-    isAttrGenerator = true;
-    defTypePrefix = "Attr";
-    valueType = "Attribute";
-  }
+      : DefGenerator(records.getAllDerivedDefinitions("AttrDef"), os, "Attr",
+                     "Attribute", /*isAttrGenerator=*/true) {}
 };
 /// A specialized generator for TypeDefs.
 struct TypeDefGenerator : public DefGenerator {
   TypeDefGenerator(const llvm::RecordKeeper &records, raw_ostream &os)
-      : DefGenerator(records.getAllDerivedDefinitions("TypeDef"), os) {
-    defTypePrefix = "Type";
-    valueType = "Type";
-  }
+      : DefGenerator(records.getAllDerivedDefinitions("TypeDef"), os, "Type",
+                     "Type", /*isAttrGenerator=*/false) {}
 };
 } // end anonymous namespace
 
 //===----------------------------------------------------------------------===//
 // GEN: Declarations
 //===----------------------------------------------------------------------===//
 
 /// Print this above all the other declarations. Contains type declarations used
 /// later on.
 static const char *const typeDefDeclHeader = R"(
 namespace mlir {
 class AsmParser;
-class DialectAsmParser;
 class AsmPrinter;
-class DialectAsmPrinter;
-} // namespace mlir
-)";
-
-/// The code block for the start of a typeDef class declaration -- singleton
-/// case.
-///
-/// {0}: The name of the def class.
-/// {1}: The name of the type base class.
-/// {2}: The name of the base value type, e.g. Attribute or Type.
-/// {3}: The tablegen record type prefix, e.g. Attr or Type.
-/// {4}: The traits of the def class.
-static const char *const defDeclSingletonBeginStr = R"(
-  class {0} : public ::mlir::{2}::{3}Base<{0}, {1}, ::mlir::{2}Storage{4}> {{
-  public:
-    /// Inherit some necessary constructors from '{3}Base'.
-    using Base::Base;
-)";
-
-/// The code block for the start of a class declaration -- parametric case.
-///
-/// {0}: The name of the def class.
-/// {1}: The name of the base class.
-/// {2}: The def storage class namespace.
-/// {3}: The storage class name.
-/// {4}: The name of the base value type, e.g. Attribute or Type.
-/// {5}: The tablegen record type prefix, e.g. Attr or Type.
-/// {6}: The traits of the def class.
-static const char *const defDeclParametricBeginStr = R"(
-  namespace {2} {
-    struct {3};
-  } // end namespace {2}
-  class {0} : public ::mlir::{4}::{5}Base<{0}, {1},
-                                         {2}::{3}{6}> {{
-  public:
-    /// Inherit some necessary constructors from '{5}Base'.
-    using Base::Base;
-
-)";
-
-/// The code snippet for print/parse of an Attribute/Type.
-///
-/// {0}: The name of the base value type, e.g. Attribute or Type.
-/// {1}: Extra parser parameters.
-static const char *const defDeclParsePrintStr = R"(
-    static ::mlir::{0} parse(::mlir::AsmParser &parser{1});
-    void print(::mlir::AsmPrinter &printer) const;
-)";
-
-/// The code block for the verify method declaration.
-///
-/// {0}: List of parameters, parameters style.
-static const char *const defDeclVerifyStr = R"(
-    using Base::getChecked;
-    static ::mlir::LogicalResult verify(::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError{0});
+} // end namespace mlir
 )";
 
-/// Emit the builders for the given def.
-static void emitBuilderDecls(const AttrOrTypeDef &def, raw_ostream &os,
-                             ParamCommaFormatter &paramTypes) {
-  StringRef typeClass = def.getCppClassName();
-  bool genCheckedMethods = def.genVerifyDecl();
-  if (!def.skipDefaultBuilders()) {
-    os << llvm::formatv(
-        "    static {0} get(::mlir::MLIRContext *context{1});\n", typeClass,
-        paramTypes);
-    if (genCheckedMethods) {
-      os << llvm::formatv("    static {0} "
-                          "getChecked(llvm::function_ref<::mlir::"
-                          "InFlightDiagnostic()> emitError, "
-                          "::mlir::MLIRContext *context{1});\n",
-                          typeClass, paramTypes);
-    }
-  }
-
-  // Generate the builders specified by the user.
-  for (const AttrOrTypeBuilder &builder : def.getBuilders()) {
-    std::string paramStr;
-    llvm::raw_string_ostream paramOS(paramStr);
-    llvm::interleaveComma(
-        builder.getParameters(), paramOS,
-        [&](const AttrOrTypeBuilder::Parameter &param) {
-          // Note: AttrOrTypeBuilder parameters are guaranteed to have names.
-          paramOS << param.getCppType() << " " << *param.getName();
-          if (Optional<StringRef> defaultParamValue = param.getDefaultValue())
-            paramOS << " = " << *defaultParamValue;
-        });
-    paramOS.flush();
-
-    // Generate the `get` variant of the builder.
-    os << "    static " << typeClass << " get(";
-    if (!builder.hasInferredContextParameter()) {
-      os << "::mlir::MLIRContext *context";
-      if (!paramStr.empty())
-        os << ", ";
-    }
-    os << paramStr << ");\n";
-
-    // Generate the `getChecked` variant of the builder.
-    if (genCheckedMethods) {
-      os << "    static " << typeClass
-         << " getChecked(llvm::function_ref<mlir::InFlightDiagnostic()> "
-            "emitError";
-      if (!builder.hasInferredContextParameter())
-        os << ", ::mlir::MLIRContext *context";
-      if (!paramStr.empty())
-        os << ", ";
-      os << paramStr << ");\n";
-    }
-  }
-}
-
-static void emitInterfaceMethodDecls(const InterfaceTrait *trait,
-                                     raw_ostream &os) {
-  Interface interface = trait->getInterface();
-
-  // Get the set of methods that should always be declared.
-  auto alwaysDeclaredMethodsVec = trait->getAlwaysDeclaredMethods();
-  llvm::StringSet<> alwaysDeclaredMethods;
-  alwaysDeclaredMethods.insert(alwaysDeclaredMethodsVec.begin(),
-                               alwaysDeclaredMethodsVec.end());
-
-  for (const InterfaceMethod &method : interface.getMethods()) {
-    // Don't declare if the method has a body.
-    if (method.getBody())
-      continue;
-    // Don't declare if the method has a default implementation and the def
-    // didn't request that it always be declared.
-    if (method.getDefaultImplementation() &&
-        !alwaysDeclaredMethods.count(method.getName()))
-      continue;
-
-    // Emit the method declaration.
-    os << "    " << (method.isStatic() ? "static " : "")
-       << method.getReturnType() << " " << method.getName() << "(";
-    llvm::interleaveComma(method.getArguments(), os,
-                          [&](const InterfaceMethod::Argument &arg) {
-                            os << arg.type << " " << arg.name;
-                          });
-    os << ")" << (method.isStatic() ? "" : " const") << ";\n";
-  }
-}
-
-void DefGenerator::emitDefDecl(const AttrOrTypeDef &def) {
-  SmallVector<AttrOrTypeParameter, 4> params;
-  def.getParameters(params);
-
-  // Build the trait list for this def.
-  std::vector<std::string> traitList;
-  StringSet<> traitSet;
-  for (const Trait &baseTrait : def.getTraits()) {
-    std::string traitStr;
-    if (const auto *trait = dyn_cast<NativeTrait>(&baseTrait))
-      traitStr = trait->getFullyQualifiedTraitName();
-    else if (const auto *trait = dyn_cast<InterfaceTrait>(&baseTrait))
-      traitStr = trait->getFullyQualifiedTraitName();
-    else
-      llvm_unreachable("unexpected Attribute/Type trait type");
-
-    if (traitSet.insert(traitStr).second)
-      traitList.emplace_back(std::move(traitStr));
-  }
-  std::string traitStr;
-  if (!traitList.empty())
-    traitStr = ", " + llvm::join(traitList, ", ");
-
-  // Emit the beginning string template: either the singleton or parametric
-  // template.
-  if (def.getNumParameters() == 0) {
-    os << formatv(defDeclSingletonBeginStr, def.getCppClassName(),
-                  def.getCppBaseClassName(), valueType, defTypePrefix,
-                  traitStr);
-  } else {
-    os << formatv(defDeclParametricBeginStr, def.getCppClassName(),
-                  def.getCppBaseClassName(), def.getStorageNamespace(),
-                  def.getStorageClassName(), valueType, defTypePrefix,
-                  traitStr);
-  }
-
-  // Emit the extra declarations first in case there's a definition in there.
-  if (Optional<StringRef> extraDecl = def.getExtraDecls())
-    os << *extraDecl << "\n";
-
-  ParamCommaFormatter emitTypeNamePairsAfterComma(
-      ParamCommaFormatter::EmitFormat::TypeNamePairs, params);
-  if (!params.empty()) {
-    emitBuilderDecls(def, os, emitTypeNamePairsAfterComma);
-
-    // Emit the verify invariants declaration.
-    if (def.genVerifyDecl())
-      os << llvm::formatv(defDeclVerifyStr, emitTypeNamePairsAfterComma);
-  }
-
-  // Emit the mnenomic, if specified.
-  if (auto mnenomic = def.getMnemonic()) {
-    os << "    static constexpr ::llvm::StringLiteral getMnemonic() {\n"
-       << "      return ::llvm::StringLiteral(\"" << mnenomic << "\");\n"
-       << "    }\n";
-
-    // If mnemonic specified, emit print/parse declarations.
-    if (def.getParserCode() || def.getPrinterCode() ||
-        def.getAssemblyFormat() || !params.empty()) {
-      os << llvm::formatv(defDeclParsePrintStr, valueType,
-                          isAttrGenerator ? ", ::mlir::Type type" : "");
-    }
-  }
-
-  if (def.genAccessors()) {
-    SmallVector<AttrOrTypeParameter, 4> parameters;
-    def.getParameters(parameters);
-
-    for (AttrOrTypeParameter &parameter : parameters) {
-      os << formatv("    {0} {1}() const;\n", parameter.getCppAccessorType(),
-                    getParameterAccessorName(parameter.getName()));
-    }
-  }
-
-  // Emit any interface method declarations.
-  for (const Trait &trait : def.getTraits()) {
-    if (const auto *traitDef = dyn_cast<InterfaceTrait>(&trait)) {
-      if (traitDef->shouldDeclareMethods())
-        emitInterfaceMethodDecls(traitDef, os);
-    }
-  }
-
-  // End the decl.
-  os << "  };\n";
-}
-
 bool DefGenerator::emitDecls(StringRef selectedDialect) {
-  emitSourceFileHeader((defTypePrefix + "Def Declarations").str(), os);
-  IfDefScope scope("GET_" + defTypePrefix.upper() + "DEF_CLASSES", os);
+  emitSourceFileHeader((defType + "Def Declarations").str(), os);
+  IfDefScope scope("GET_" + defType.upper() + "DEF_CLASSES", os);
 
   // Output the common "header".
   os << typeDefDeclHeader;
 
   SmallVector<AttrOrTypeDef, 16> defs;
   collectAllDefs(selectedDialect, defRecords, defs);
   if (defs.empty())
     return false;
   {
     NamespaceEmitter nsEmitter(os, defs.front().getDialect());
 
     // Declare all the def classes first (in case they reference each other).
     for (const AttrOrTypeDef &def : defs)
-      os << "  class " << def.getCppClassName() << ";\n";
+      os << "class " << def.getCppClassName() << ";\n";
 
     // Emit the declarations.
     for (const AttrOrTypeDef &def : defs)
-      emitDefDecl(def);
+      DefGen(def).emitDecl(os);
   }
   // Emit the TypeID explicit specializations to have a single definition for
   // each of these.
   for (const AttrOrTypeDef &def : defs)
     if (!def.getDialect().getCppNamespace().empty())
       os << "DECLARE_EXPLICIT_TYPE_ID(" << def.getDialect().getCppNamespace()
          << "::" << def.getCppClassName() << ")\n";
 
   return false;
 }
 
 //===----------------------------------------------------------------------===//
 // GEN: Def List
 //===----------------------------------------------------------------------===//
 
 void DefGenerator::emitTypeDefList(ArrayRef<AttrOrTypeDef> defs) {
-  IfDefScope scope("GET_" + defTypePrefix.upper() + "DEF_LIST", os);
+  IfDefScope scope("GET_" + defType.upper() + "DEF_LIST", os);
   auto interleaveFn = [&](const AttrOrTypeDef &def) {
     os << def.getDialect().getCppNamespace() << "::" << def.getCppClassName();
   };
   llvm::interleave(defs, os, interleaveFn, ",\n");
   os << "\n";
 }
 
 //===----------------------------------------------------------------------===//
 // GEN: Definitions
 //===----------------------------------------------------------------------===//
 
-/// The code block used to start the auto-generated parser function.
-///
-/// {0}: The name of the base value type, e.g. Attribute or Type.
-/// {1}: Additional parser parameters.
-static const char *const defParserDispatchStartStr = R"(
-static ::mlir::OptionalParseResult generated{0}Parser(
-                                      ::mlir::AsmParser &parser,
-                                      ::llvm::StringRef mnemonic{1},
-                                      ::mlir::{0} &value) {{
-)";
-
 /// The code block for default attribute parser/printer dispatch boilerplate.
 /// {0}: the dialect fully qualified class name.
 static const char *const dialectDefaultAttrPrinterParserDispatch = R"(
 /// Parse an attribute registered to this dialect.
 ::mlir::Attribute {0}::parseAttribute(::mlir::DialectAsmParser &parser,
                                       ::mlir::Type type) const {{
   ::llvm::SMLoc typeLoc = parser.getCurrentLocation();
   ::llvm::StringRef attrTag;

 /// Print a type registered to this dialect.
 void {0}::printType(::mlir::Type type,
                     ::mlir::DialectAsmPrinter &printer) const {{
   if (succeeded(generatedTypePrinter(type, printer)))
     return;
 }
 )";
 
-/// The code block used to start the auto-generated printer function.
-///
-/// {0}: The name of the base value type, e.g. Attribute or Type.
-static const char *const defPrinterDispatchStartStr = R"(
-static ::mlir::LogicalResult generated{0}Printer(
-                         ::mlir::{0} def, ::mlir::AsmPrinter &printer) {{
-  return ::llvm::TypeSwitch<::mlir::{0}, ::mlir::LogicalResult>(def)
-)";
-
-/// Beginning of storage class.
-/// {0}: Storage class namespace.
-/// {1}: Storage class c++ name.
-/// {2}: Parameters parameters.
-/// {3}: Parameter initializer string.
-/// {4}: Parameter types.
-/// {5}: The name of the base value type, e.g. Attribute or Type.
-static const char *const defStorageClassBeginStr = R"(
-namespace {0} {{
-  struct {1} : public ::mlir::{5}Storage {{
-    {1} ({2})
-      : {3} {{ }
-
-    /// The hash key is a tuple of the parameter types.
-    using KeyTy = std::tuple<{4}>;
-)";
-
-/// The storage class' constructor template.
-///
-/// {0}: storage class name.
-/// {1}: The name of the base value type, e.g. Attribute or Type.
-static const char *const defStorageClassConstructorBeginStr = R"(
-    /// Define a construction method for creating a new instance of this
-    /// storage.
-    static {0} *construct(::mlir::{1}StorageAllocator &allocator,
-                          const KeyTy &tblgenKey) {{
-)";
-
-/// The storage class' constructor return template.
-///
-/// {0}: storage class name.
-/// {1}: list of parameters.
-static const char *const defStorageClassConstructorEndStr = R"(
-      return new (allocator.allocate<{0}>())
-          {0}({1});
-    }
-)";
-
-/// Use tgfmt to emit custom allocation code for each parameter, if necessary.
-static void emitStorageParameterAllocation(const AttrOrTypeDef &def,
-                                           raw_ostream &os) {
-  SmallVector<AttrOrTypeParameter> parameters;
-  def.getParameters(parameters);
-  FmtContext fmtCtxt = FmtContext().addSubst("_allocator", "allocator");
-  for (AttrOrTypeParameter &parameter : parameters) {
-    if (Optional<StringRef> allocCode = parameter.getAllocator()) {
-      fmtCtxt.withSelf(parameter.getName());
-      fmtCtxt.addSubst("_dst", parameter.getName());
-      os << "      " << tgfmt(*allocCode, &fmtCtxt) << "\n";
-    }
-  }
-}
-
-/// Builds a code block that initializes the attribute storage of 'def'.
-/// Attribute initialization is separated from Type initialization given that
-/// the Attribute also needs to initialize its self-type, which has multiple
-/// means of initialization.
-static std::string buildAttributeStorageParamInitializer(
-    const AttrOrTypeDef &def, ArrayRef<AttrOrTypeParameter> parameters) {
-  std::string paramInitializer;
-  llvm::raw_string_ostream paramOS(paramInitializer);
-  paramOS << "::mlir::AttributeStorage(";
-
-  // If this is an attribute, we need to check for value type initialization.
-  Optional<size_t> selfParamIndex;
-  for (auto it : llvm::enumerate(parameters)) {
-    const auto *selfParam = dyn_cast<AttributeSelfTypeParameter>(&it.value());
-    if (!selfParam)
-      continue;
-    if (selfParamIndex) {
-      llvm::PrintFatalError(def.getLoc(),
-                            "Only one attribute parameter can be marked as "
-                            "AttributeSelfTypeParameter");
-    }
-    paramOS << selfParam->getName();
-    selfParamIndex = it.index();
-  }
-
-  // If we didn't find a self param, but the def has a type builder we use that
-  // to construct the type.
-  if (!selfParamIndex) {
-    const AttrDef &attrDef = cast<AttrDef>(def);
-    if (Optional<StringRef> typeBuilder = attrDef.getTypeBuilder()) {
-      FmtContext fmtContext;
-      for (const AttrOrTypeParameter &param : parameters)
-        fmtContext.addSubst(("_" + param.getName()).str(), param.getName());
-      paramOS << tgfmt(*typeBuilder, &fmtContext);
-    }
-  }
-  paramOS << ")";
-
-  // Append the parameters to the initializer.
-  for (auto it : llvm::enumerate(parameters))
-    if (it.index() != selfParamIndex)
-      paramOS << llvm::formatv(", {0}({0})", it.value().getName());
-
-  return paramOS.str();
-}
-
-void DefGenerator::emitStorageClass(const AttrOrTypeDef &def) {
-  SmallVector<AttrOrTypeParameter, 4> params;
-  def.getParameters(params);
-
-  // Collect the parameter types.
-  auto parameterTypes =
-      llvm::map_range(params, [](const AttrOrTypeParameter &parameter) {
-        return parameter.getCppType();
-      });
-  std::string parameterTypeList = llvm::join(parameterTypes, ", ");
-
-  // Collect the parameter initializer.
-  std::string paramInitializer;
-  if (isAttrGenerator) {
-    paramInitializer = buildAttributeStorageParamInitializer(def, params);
-
-  } else {
-    llvm::raw_string_ostream initOS(paramInitializer);
-    llvm::interleaveComma(params, initOS, [&](const AttrOrTypeParameter &it) {
-      initOS << llvm::formatv("{0}({0})", it.getName());
-    });
-  }
-
-  // * Emit most of the storage class up until the hashKey body.
-  os << formatv(
-      defStorageClassBeginStr, def.getStorageNamespace(),
-      def.getStorageClassName(),
-      ParamCommaFormatter(ParamCommaFormatter::EmitFormat::TypeNamePairs,
-                          params, /*prependComma=*/false),
-      paramInitializer, parameterTypeList, valueType);
-
-  // * Emit the comparison method.
-  os << "  bool operator==(const KeyTy &tblgenKey) const {\n";
-  for (auto it : llvm::enumerate(params)) {
-    os << "    if (!(";
-
-    // Build the comparator context.
-    bool isSelfType = isa<AttributeSelfTypeParameter>(it.value());
-    FmtContext context;
-    context.addSubst("_lhs", isSelfType ? "getType()" : it.value().getName())
-        .addSubst("_rhs", "std::get<" + Twine(it.index()) + ">(tblgenKey)");
-
-    // Use the parameter specified comparator if possible, otherwise default to
-    // operator==.
-    Optional<StringRef> comparator = it.value().getComparator();
-    os << tgfmt(comparator ? *comparator : "$_lhs == $_rhs", &context);
-    os << "))\n      return false;\n";
-  }
-  os << "    return true;\n  }\n";
-
-  // * Emit the haskKey method.
-  os << "  static ::llvm::hash_code hashKey(const KeyTy &tblgenKey) {\n";
-
-  // Extract each parameter from the key.
-  os << "      return ::llvm::hash_combine(";
-  llvm::interleaveComma(
-      llvm::seq<unsigned>(0, params.size()), os,
-      [&](unsigned it) { os << "std::get<" << it << ">(tblgenKey)"; });
-  os << ");\n    }\n";
-
-  // * Emit the construct method.
-
-  // If user wants to build the storage constructor themselves, declare it
-  // here and then they can write the definition elsewhere.
-  if (def.hasStorageCustomConstructor()) {
-    os << llvm::formatv("    static {0} *construct(::mlir::{1}StorageAllocator "
-                        "&allocator, const KeyTy &tblgenKey);\n",
-                        def.getStorageClassName(), valueType);
-
-    // Otherwise, generate one.
-  } else {
-    // First, unbox the parameters.
-    os << formatv(defStorageClassConstructorBeginStr, def.getStorageClassName(),
-                  valueType);
-    for (unsigned i = 0, e = params.size(); i < e; ++i) {
-      os << formatv("      auto {0} = std::get<{1}>(tblgenKey);\n",
-                    params[i].getName(), i);
-    }
-
-    // Second, reassign the parameter variables with allocation code, if it's
-    // specified.
-    emitStorageParameterAllocation(def, os);
-
-    // Last, return an allocated copy.
-    auto parameterNames = llvm::map_range(
-        params, [](const auto &param) { return param.getName(); });
-    os << formatv(defStorageClassConstructorEndStr, def.getStorageClassName(),
-                  llvm::join(parameterNames, ", "));
-  }
-
-  // * Emit the parameters as storage class members.
-  for (const AttrOrTypeParameter &parameter : params) {
-    // Attribute value types are not stored as fields in the storage.
-    if (!isa<AttributeSelfTypeParameter>(parameter))
-      os << "      " << parameter.getCppType() << " " << parameter.getName()
-         << ";\n";
-  }
-  os << "  };\n";
-
-  os << "} // namespace " << def.getStorageNamespace() << "\n";
-}
-
-void DefGenerator::emitParsePrint(const AttrOrTypeDef &def) {
-  auto printerCode = def.getPrinterCode();
-  auto parserCode = def.getParserCode();
-  auto assemblyFormat = def.getAssemblyFormat();
-  if (assemblyFormat && (printerCode || parserCode)) {
-    // Custom assembly format cannot be specified at the same time as either
-    // custom printer or parser code.
-    PrintFatalError(def.getLoc(),
-                    def.getName() + ": assembly format cannot be specified at "
-                                    "the same time as printer or parser code");
-  }
-
-  // Generate a parser and printer based on the assembly format, if specified.
-  if (assemblyFormat) {
-    // A custom assembly format requires accessors to be generated for the
-    // generated printer.
-    if (!def.genAccessors()) {
-      PrintFatalError(def.getLoc(),
-                      def.getName() +
-                          ": the generated printer from 'assemblyFormat' "
-                          "requires 'genAccessors' to be true");
-    }
-    return generateAttrOrTypeFormat(def, os);
-  }
-
-  // Emit the printer code, if specified.
-  if (printerCode) {
-    // Both the mnenomic and printerCode must be defined (for parity with
-    // parserCode).
-    os << "void " << def.getCppClassName()
-       << "::print(::mlir::AsmPrinter &printer) const {\n";
-    if (printerCode->empty()) {
-      // If no code specified, emit error.
-      PrintFatalError(def.getLoc(),
-                      def.getName() +
-                          ": printer (if specified) must have non-empty code");
-    }
-    FmtContext fmtCtxt = FmtContext().addSubst("_printer", "printer");
-    os << tgfmt(*printerCode, &fmtCtxt) << "\n}\n";
-  }
-
-  // Emit the parser code, if specified.
-  if (parserCode) {
-    FmtContext fmtCtxt;
-    fmtCtxt.addSubst("_parser", "parser")
-        .addSubst("_ctxt", "parser.getContext()");
-
-    // The mnenomic must be defined so the dispatcher knows how to dispatch.
-    os << llvm::formatv("::mlir::{0} {1}::parse("
-                        "::mlir::AsmParser &parser",
-                        valueType, def.getCppClassName());
-    if (isAttrGenerator) {
-      // Attributes also accept a type parameter instead of a context.
-      os << ", ::mlir::Type type";
-      fmtCtxt.addSubst("_type", "type");
-    }
-    os << ") {\n";
-
-    if (parserCode->empty()) {
-      PrintFatalError(def.getLoc(),
-                      def.getName() +
-                          ": parser (if specified) must have non-empty code");
-    }
-    os << tgfmt(*parserCode, &fmtCtxt) << "\n}\n";
-  }
-}
-
-/// Replace all instances of 'from' to 'to' in `str` and return the new string.
-static std::string replaceInStr(std::string str, StringRef from, StringRef to) {
-  size_t pos = 0;
-  while ((pos = str.find(from.data(), pos, from.size())) != std::string::npos)
-    str.replace(pos, from.size(), to.data(), to.size());
-  return str;
-}
-
-/// Emit the builders for the given def.
-static void emitBuilderDefs(const AttrOrTypeDef &def, raw_ostream &os,
-                            ArrayRef<AttrOrTypeParameter> params) {
-  bool genCheckedMethods = def.genVerifyDecl();
-  StringRef className = def.getCppClassName();
-  if (!def.skipDefaultBuilders()) {
-    os << llvm::formatv(
-        "{0} {0}::get(::mlir::MLIRContext *context{1}) {{\n"
-        "  return Base::get(context{2});\n}\n",
-        className,
-        ParamCommaFormatter(ParamCommaFormatter::EmitFormat::TypeNamePairs,
-                            params),
-        ParamCommaFormatter(ParamCommaFormatter::EmitFormat::JustParams,
-                            params));
-    if (genCheckedMethods) {
-      os << llvm::formatv(
-          "{0} {0}::getChecked("
-          "llvm::function_ref<::mlir::InFlightDiagnostic()> emitError, "
-          "::mlir::MLIRContext *context{1}) {{\n"
-          "  return Base::getChecked(emitError, context{2});\n}\n",
-          className,
-          ParamCommaFormatter(ParamCommaFormatter::EmitFormat::TypeNamePairs,
-                              params),
-          ParamCommaFormatter(ParamCommaFormatter::EmitFormat::JustParams,
-                              params));
-    }
-  }
-
-  auto builderFmtCtx =
-      FmtContext().addSubst("_ctxt", "context").addSubst("_get", "Base::get");
-  auto inferredCtxBuilderFmtCtx = FmtContext().addSubst("_get", "Base::get");
-  auto checkedBuilderFmtCtx = FmtContext().addSubst("_ctxt", "context");
-
-  // Generate the builders specified by the user.
-  for (const AttrOrTypeBuilder &builder : def.getBuilders()) {
-    Optional<StringRef> body = builder.getBody();
-    if (!body)
-      continue;
-    std::string paramStr;
-    llvm::raw_string_ostream paramOS(paramStr);
-    llvm::interleaveComma(builder.getParameters(), paramOS,
-                          [&](const AttrOrTypeBuilder::Parameter &param) {
-                            // Note: AttrOrTypeBuilder parameters are guaranteed
-                            // to have names.
-                            paramOS << param.getCppType() << " "
-                                    << *param.getName();
-                          });
-    paramOS.flush();
-
-    // Emit the `get` variant of the builder.
-    os << llvm::formatv("{0} {0}::get(", className);
-    if (!builder.hasInferredContextParameter()) {
-      os << "::mlir::MLIRContext *context";
-      if (!paramStr.empty())
-        os << ", ";
-      os << llvm::formatv("{0}) {{\n  {1};\n}\n", paramStr,
-                          tgfmt(*body, &builderFmtCtx).str());
-    } else {
-      os << llvm::formatv("{0}) {{\n  {1};\n}\n", paramStr,
-                          tgfmt(*body, &inferredCtxBuilderFmtCtx).str());
-    }
-
-    // Emit the `getChecked` variant of the builder.
-    if (genCheckedMethods) {
-      os << llvm::formatv("{0} "
-                          "{0}::getChecked(llvm::function_ref<::mlir::"
-                          "InFlightDiagnostic()> emitErrorFn",
-                          className);
-      std::string checkedBody =
-          replaceInStr(body->str(), "$_get(", "Base::getChecked(emitErrorFn, ");
-      if (!builder.hasInferredContextParameter()) {
-        os << ", ::mlir::MLIRContext *context";
-        checkedBody = tgfmt(checkedBody, &checkedBuilderFmtCtx).str();
-      }
-      if (!paramStr.empty())
-        os << ", ";
-      os << llvm::formatv("{0}) {{\n  {1};\n}\n", paramStr, checkedBody);
-    }
-  }
-}
-
-/// Print all the def-specific definition code.
-void DefGenerator::emitDefDef(const AttrOrTypeDef &def) {
-  NamespaceEmitter ns(os, def.getDialect());
-
-  SmallVector<AttrOrTypeParameter, 4> parameters;
-  def.getParameters(parameters);
-  if (!parameters.empty()) {
-    // Emit the storage class, if requested and necessary.
-    if (def.genStorageClass())
-      emitStorageClass(def);
-
-    // Emit the builders for this def.
-    emitBuilderDefs(def, os, parameters);
-
-    // Generate accessor definitions only if we also generate the storage class.
-    // Otherwise, let the user define the exact accessor definition.
-    if (def.genAccessors() && def.genStorageClass()) {
-      for (const AttrOrTypeParameter &param : parameters) {
-        SmallString<32> paramStorageName;
-        if (isa<AttributeSelfTypeParameter>(param)) {
-          Twine("getType().cast<" + param.getCppType() + ">()")
-              .toVector(paramStorageName);
-        } else {
-          paramStorageName = param.getName();
-        }
-
-        os << formatv("{0} {3}::{1}() const {{ return getImpl()->{2}; }\n",
-                      param.getCppAccessorType(),
-                      getParameterAccessorName(param.getName()),
-                      paramStorageName, def.getCppClassName());
-      }
-    }
-  }
-
-  // If mnemonic is specified maybe print definitions for the parser and printer
-  // code, if they're specified.
-  if (def.getMnemonic())
-    emitParsePrint(def);
-}
-
 /// Emit the dialect printer/parser dispatcher. User's code should call these
 /// functions from their dialect's print/parse methods.
 void DefGenerator::emitParsePrintDispatch(ArrayRef<AttrOrTypeDef> defs) {
   if (llvm::none_of(defs, [](const AttrOrTypeDef &def) {
         return def.getMnemonic().hasValue();
       })) {
     return;
   }
+  // Declare the parser.
+  SmallVector<MethodParameter> params = {{"::mlir::AsmParser &", "parser"},
+                                         {"::llvm::StringRef", "mnemonic"}};
+  if (isAttrGenerator)
+    params.emplace_back("::mlir::Type", "type");
+  params.emplace_back(strfmt("::mlir::{0} &", valueType), "value");
+  Method parse("::mlir::OptionalParseResult",
+               strfmt("generated{0}Parser", valueType), Method::StaticInline,
+               std::move(params));
+  // Declare the printer.
+  Method printer("::mlir::LogicalResult",
+                 strfmt("generated{0}Printer", valueType), Method::StaticInline,
+                 {{strfmt("::mlir::{0}", valueType), "def"},
+                  {"::mlir::AsmPrinter &", "printer"}});
 
   // The parser dispatch is just a list of if-elses, matching on the mnemonic
   // and calling the def's parse function.
-  os << llvm::formatv(defParserDispatchStartStr, valueType,
-                      isAttrGenerator ? ", ::mlir::Type type" : "");
-  for (const AttrOrTypeDef &def : defs) {
-    if (def.getMnemonic()) {
-      os << formatv("  if (mnemonic == {0}::{1}::getMnemonic()) { \n"
-                    "    value = {0}::{1}::",
-                    def.getDialect().getCppNamespace(), def.getCppClassName());
-
-      // If the def has no parameters and no parser code, just invoke a normal
-      // `get`.
-      if (def.getNumParameters() == 0 && !def.getParserCode()) {
-        os << "get(parser.getContext());\n";
-        os << "    return ::mlir::success(!!value);\n  }\n";
-        continue;
-      }
-
-      os << "parse(parser" << (isAttrGenerator ? ", type" : "")
-         << ");\n    return ::mlir::success(!!value);\n  }\n";
-    }
-  }
-  os << "  return {};\n";
-  os << "}\n\n";
-
+  const char *const getValueForMnemonic =
+      R"(  if (mnemonic == {0}::getMnemonic()) {{
+    value = {0}::{1};
+    return ::mlir::success(!!value);
+)";
   // The printer dispatch uses llvm::TypeSwitch to find and call the correct
   // printer.
-  os << llvm::formatv(defPrinterDispatchStartStr, valueType);
-  for (const AttrOrTypeDef &def : defs) {
-    Optional<StringRef> mnemonic = def.getMnemonic();
-    if (!mnemonic)
+  printer.body() << "  return ::llvm::TypeSwitch<::mlir::" << valueType
+                 << ", ::mlir::LogicalResult>(def)";
+  const char *const printValue = R"(    .Case<{0}>([&](auto t) {{
+      printer << {0}::getMnemonic();{1}
+      return ::mlir::success();
+    })
+)";
+  for (auto &def : defs) {
+    if (!def.getMnemonic())
       continue;
+    std::string defClass = strfmt(
+        "{0}::{1}", def.getDialect().getCppNamespace(), def.getCppClassName());
+    // If the def has no parameters or parser code, invoke a normal `get`.
+    std::string parseOrGet =
+        def.needsParserPrinter() || def.hasGeneratedParser()
+            ? strfmt("parse(parser{0})", isAttrGenerator ? ", type" : "")
+            : "get(parser.getContext())";
+    parse.body() << llvm::formatv(getValueForMnemonic, defClass, parseOrGet);
 
-    StringRef cppNamespace = def.getDialect().getCppNamespace();
-    StringRef cppClassName = def.getCppClassName();
-    os << formatv("    .Case<{0}::{1}>([&]({0}::{1} t) {{\n      ",
-                  cppNamespace, cppClassName);
-
-    os << formatv("printer << {0}::{1}::getMnemonic();", cppNamespace,
-                  cppClassName);
     // If the def has no parameters and no printer, just print the mnemonic.
-    if (def.getNumParameters() != 0 || def.getPrinterCode())
-      os << "t.print(printer);";
-    os << "\n      return ::mlir::success();\n    })\n";
-  }
-  os << llvm::formatv(
-      "    .Default([](::mlir::{0}) {{ return ::mlir::failure(); });\n}\n\n",
-      valueType);
+    StringRef printDef = "";
+    if (def.needsParserPrinter() || def.hasGeneratedPrinter())
+      printDef = "\nt.print(printer);";
+    printer.body() << llvm::formatv(printValue, defClass, printDef);
+  }
+  parse.body() << "  return {};";
+  printer.body() << "    .Default([](auto) { return ::mlir::failure(); });";
+
+  raw_indented_ostream indentedOs(os);
+  parse.writeDeclTo(indentedOs);
+  printer.writeDeclTo(indentedOs);
 }
 
 bool DefGenerator::emitDefs(StringRef selectedDialect) {
-  emitSourceFileHeader((defTypePrefix + "Def Definitions").str(), os);
+  emitSourceFileHeader((defType + "Def Definitions").str(), os);
 
   SmallVector<AttrOrTypeDef, 16> defs;
   collectAllDefs(selectedDialect, defRecords, defs);
   if (defs.empty())
     return false;
   emitTypeDefList(defs);
 
-  IfDefScope scope("GET_" + defTypePrefix.upper() + "DEF_CLASSES", os);
+  IfDefScope scope("GET_" + defType.upper() + "DEF_CLASSES", os);
   emitParsePrintDispatch(defs);
   for (const AttrOrTypeDef &def : defs) {
-    emitDefDef(def);
+    {
+      NamespaceEmitter ns(os, def.getDialect());
+      DefGen gen(def);
+      gen.emitDef(os);
+    }
     // Emit the TypeID explicit specializations to have a single symbol def.
     if (!def.getDialect().getCppNamespace().empty())
       os << "DEFINE_EXPLICIT_TYPE_ID(" << def.getDialect().getCppNamespace()
          << "::" << def.getCppClassName() << ")\n";
   }
 
   // Emit the default parser/printer for Attributes if the dialect asked for it.
-  if (valueType == "Attribute" &&
-      defs.front().getDialect().useDefaultAttributePrinterParser())
+  if (isAttrGenerator &&
+      defs.front().getDialect().useDefaultAttributePrinterParser()) {
     os << llvm::formatv(dialectDefaultAttrPrinterParserDispatch,
                         defs.front().getDialect().getCppClassName());
+  }
 
   // Emit the default parser/printer for Types if the dialect asked for it.
-  if (valueType == "Type" &&
-      defs.front().getDialect().useDefaultTypePrinterParser())
+  if (!isAttrGenerator &&
+      defs.front().getDialect().useDefaultTypePrinterParser()) {
     os << llvm::formatv(dialectDefaultTypePrinterParserDispatch,
                         defs.front().getDialect().getCppClassName());
+  }
 
   return false;
 }
 
 //===----------------------------------------------------------------------===//
 // GEN: Registration hooks
 //===----------------------------------------------------------------------===//
 

mlir/tools/mlir-tblgen/AttrOrTypeFormatGen.h

 //===- AttrOrTypeFormatGen.h - MLIR attribute and type format generator ---===//
 //
 // 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 MLIR_TOOLS_MLIRTBLGEN_ATTRORTYPEFORMATGEN_H_
 #define MLIR_TOOLS_MLIRTBLGEN_ATTRORTYPEFORMATGEN_H_
 
-#include "llvm/Support/raw_ostream.h"
-
-#include <string>
+#include "mlir/TableGen/Class.h"
 
 namespace mlir {
 namespace tblgen {
 class AttrOrTypeDef;
 
 /// Generate a parser and printer based on a custom assembly format for an
 /// attribute or type.
-void generateAttrOrTypeFormat(const AttrOrTypeDef &def, llvm::raw_ostream &os);
+void generateAttrOrTypeFormat(const AttrOrTypeDef &def, MethodBody &parser,
+                              MethodBody &printer);
 
 /// From the parameter name, get the name of the accessor function in camelcase.
 /// The first letter of the parameter is upper-cased and prefixed with "get".
 /// E.g. 'value' -> 'getValue'.
 std::string getParameterAccessorName(llvm::StringRef name);
 
 } // end namespace tblgen
 } // end namespace mlir
 
 #endif // MLIR_TOOLS_MLIRTBLGEN_ATTRORTYPEFORMATGEN_H_

mlir/tools/mlir-tblgen/AttrOrTypeFormatGen.cpp

 };
 
 } // end anonymous namespace
 
 //===----------------------------------------------------------------------===//
 // Format Strings
 //===----------------------------------------------------------------------===//
 
-/// Format for defining an attribute parser.
-///
-/// $0: The attribute C++ class name.
-static const char *const attrParserDefn = R"(
-::mlir::Attribute $0::parse(::mlir::AsmParser &$_parser,
-                             ::mlir::Type $_type) {
-)";
-
-/// Format for defining a type parser.
-///
-/// $0: The type C++ class name.
-static const char *const typeParserDefn = R"(
-::mlir::Type $0::parse(::mlir::AsmParser &$_parser) {
-)";
-
 /// Default parser for attribute or type parameters.
 static const char *const defaultParameterParser =
     "::mlir::FieldParser<$0>::parse($_parser)";
 
 /// Default printer for attribute or type parameters.
 static const char *const defaultParameterPrinter = "$_printer << $_self";
 
 /// Print an error when failing to parse an element.
 ///
 /// $0: The parameter C++ class name.
 static const char *const parseErrorStr =
     "$_parser.emitError($_parser.getCurrentLocation(), ";
 
-/// Format for defining an attribute or type printer.
-///
-/// $0: The attribute or type C++ class name.
-static const char *const attrOrTypePrinterDefn = R"(
-void $0::print(::mlir::AsmPrinter &$_printer) const {
-)";
-
 /// Loop declaration for struct parser.
 ///
 /// $0: Number of expected parameters.
 static const char *const structParseLoopStart = R"(
   for (unsigned _index = 0; _index < $0; ++_index) {
     StringRef _paramKey;
     if ($_parser.parseKeyword(&_paramKey)) {
       $_parser.emitError($_parser.getCurrentLocation(),
                          "expected a parameter name in struct");
       return {};
     }
 )";
 
 /// Terminator code segment for the struct parser loop. Check for duplicate or
 /// unknown parameters. Parse a comma except on the last element.
 ///
 /// {0}: Code template for printing an error.
 /// {1}: Number of elements in the struct.
 static const char *const structParseLoopEnd = R"({{
-      {0}"duplicate or unknown struct parameter name: ") << _paramKey;
-      return {{};
-    }
-    if ((_index != {1} - 1) && parser.parseComma())
-      return {{};
-  }
 )";
 
 /// Code format to parse a variable. Separate by lines because variable parsers
 /// may be generated inside other directives, which requires indentation.
 ///
 /// {0}: The parameter name.
 /// {1}: The parse code for the parameter.
 /// {2}: Code template for printing an error.
 /// {3}: Name of the attribute or type.
 /// {4}: C++ class of the parameter.
-static const char *const variableParser[] = {
-    "  // Parse variable '{0}'",
-    "  _result_{0} = {1};",
-    "  if (failed(_result_{0})) {{",
-    "    {2}\"failed to parse {3} parameter '{0}' which is to be a `{4}`\");",
-    "    return {{};",
-    "  }",
-};
-
-//===----------------------------------------------------------------------===//
-// Utility Functions
-//===----------------------------------------------------------------------===//
-
-/// Get a list of an attribute's or type's parameters. These can be wrapper
-/// objects around `AttrOrTypeParameter` or string inits.
-static auto getParameters(const AttrOrTypeDef &def) {
-  SmallVector<AttrOrTypeParameter> params;
-  def.getParameters(params);
-  return params;
+static const char *const variableParser = R"(
+// Parse variable '{0}'
+_result_{0} = {1};
+if (failed(_result_{0})) {{
+  {2}"failed to parse {3} parameter '{0}' which is to be a `{4}`");
+  return {{};
 }
+)";
 
 //===----------------------------------------------------------------------===//
 // AttrOrTypeFormat
 //===----------------------------------------------------------------------===//
 
 namespace {
 class AttrOrTypeFormat {
 public:
   AttrOrTypeFormat(const AttrOrTypeDef &def,
                    std::vector<std::unique_ptr<Element>> &&elements)
       : def(def), elements(std::move(elements)) {}
 
   /// Generate the attribute or type parser.
-  void genParser(raw_ostream &os);
+  void genParser(MethodBody &os);
   /// Generate the attribute or type printer.
-  void genPrinter(raw_ostream &os);
+  void genPrinter(MethodBody &os);
 
 private:
   /// Generate the parser code for a specific format element.
-  void genElementParser(Element *el, FmtContext &ctx, raw_ostream &os);
+  void genElementParser(Element *el, FmtContext &ctx, MethodBody &os);
   /// Generate the parser code for a literal.
-  void genLiteralParser(StringRef value, FmtContext &ctx, raw_ostream &os,
-                        unsigned indent = 0);
+  void genLiteralParser(StringRef value, FmtContext &ctx, MethodBody &os);
   /// Generate the parser code for a variable.
   void genVariableParser(const AttrOrTypeParameter &param, FmtContext &ctx,
-                         raw_ostream &os, unsigned indent = 0);
+                         MethodBody &os);
   /// Generate the parser code for a `params` directive.
-  void genParamsParser(ParamsDirective *el, FmtContext &ctx, raw_ostream &os);
+  void genParamsParser(ParamsDirective *el, FmtContext &ctx, MethodBody &os);
   /// Generate the parser code for a `struct` directive.
-  void genStructParser(StructDirective *el, FmtContext &ctx, raw_ostream &os);
+  void genStructParser(StructDirective *el, FmtContext &ctx, MethodBody &os);
 
   /// Generate the printer code for a specific format element.
-  void genElementPrinter(Element *el, FmtContext &ctx, raw_ostream &os);
+  void genElementPrinter(Element *el, FmtContext &ctx, MethodBody &os);
   /// Generate the printer code for a literal.
-  void genLiteralPrinter(StringRef value, FmtContext &ctx, raw_ostream &os);
+  void genLiteralPrinter(StringRef value, FmtContext &ctx, MethodBody &os);
   /// Generate the printer code for a variable.
   void genVariablePrinter(const AttrOrTypeParameter &param, FmtContext &ctx,
-                          raw_ostream &os);
+                          MethodBody &os);
   /// Generate the printer code for a `params` directive.
-  void genParamsPrinter(ParamsDirective *el, FmtContext &ctx, raw_ostream &os);
+  void genParamsPrinter(ParamsDirective *el, FmtContext &ctx, MethodBody &os);
   /// Generate the printer code for a `struct` directive.
-  void genStructPrinter(StructDirective *el, FmtContext &ctx, raw_ostream &os);
+  void genStructPrinter(StructDirective *el, FmtContext &ctx, MethodBody &os);
 
   /// The ODS definition of the attribute or type whose format is being used to
   /// generate a parser and printer.
   const AttrOrTypeDef &def;
   /// The list of top-level format elements returned by the assembly format
   /// parser.
   std::vector<std::unique_ptr<Element>> elements;
 
   /// Flags for printing spaces.
   bool shouldEmitSpace;
   bool lastWasPunctuation;
 };
 } // end anonymous namespace
 
 //===----------------------------------------------------------------------===//
 // ParserGen
 //===----------------------------------------------------------------------===//
 
-void AttrOrTypeFormat::genParser(raw_ostream &os) {
+void AttrOrTypeFormat::genParser(MethodBody &os) {
   FmtContext ctx;
   ctx.addSubst("_parser", "parser");
-
-  /// Generate the definition.
-  if (isa<AttrDef>(def)) {
-    ctx.addSubst("_type", "attrType");
-    os << tgfmt(attrParserDefn, &ctx, def.getCppClassName());
-  } else {
-    os << tgfmt(typeParserDefn, &ctx, def.getCppClassName());
-  }
+  if (isa<AttrDef>(def))
+    ctx.addSubst("_type", "type");
+  os.indent();
 
   /// Declare variables to store all of the parameters. Allocated parameters
   /// such as `ArrayRef` and `StringRef` must provide a `storageType`. Store
   /// FailureOr<T> to defer type construction for parameters that are parsed in
   /// a loop (parsers return FailureOr anyways).
-  SmallVector<AttrOrTypeParameter> params = getParameters(def);
+  ArrayRef<AttrOrTypeParameter> params = def.getParameters();
   for (const AttrOrTypeParameter &param : params) {
     os << formatv("  ::mlir::FailureOr<{0}> _result_{1};\n",
                   param.getCppStorageType(), param.getName());
   }
 
   /// Store the initial location of the parser.
   ctx.addSubst("_loc", "loc");
-  os << tgfmt("  ::llvm::SMLoc $_loc = $_parser.getCurrentLocation();\n"
-              "  (void) $_loc;\n",
+  os << tgfmt("::llvm::SMLoc $_loc = $_parser.getCurrentLocation();\n"
+              "(void) $_loc;\n",
               &ctx);
 
   /// Generate call to each parameter parser.
   for (auto &el : elements)
     genElementParser(el.get(), ctx, os);
 
   /// Generate call to the attribute or type builder. Use the checked getter
   /// if one was generated.
   if (def.genVerifyDecl()) {
-    os << tgfmt("  return $_parser.getChecked<$0>($_loc, $_parser.getContext()",
+    os << tgfmt("return $_parser.getChecked<$0>($_loc, $_parser.getContext()",
                 &ctx, def.getCppClassName());
   } else {
-    os << tgfmt("  return $0::get($_parser.getContext()", &ctx,
+    os << tgfmt("return $0::get($_parser.getContext()", &ctx,
                 def.getCppClassName());
   }
   for (const AttrOrTypeParameter &param : params)
     os << formatv(",\n    _result_{0}.getValue()", param.getName());
-  os << ");\n}\n\n";
+  os << ");";
 }
 
 void AttrOrTypeFormat::genElementParser(Element *el, FmtContext &ctx,
-                                        raw_ostream &os) {
+                                        MethodBody &os) {
   if (auto *literal = dyn_cast<LiteralElement>(el))
     return genLiteralParser(literal->getSpelling(), ctx, os);
   if (auto *var = dyn_cast<VariableElement>(el))
     return genVariableParser(var->getParam(), ctx, os);
   if (auto *params = dyn_cast<ParamsDirective>(el))
     return genParamsParser(params, ctx, os);
   if (auto *strct = dyn_cast<StructDirective>(el))
     return genStructParser(strct, ctx, os);
 
   llvm_unreachable("unknown format element");
 }
 
 void AttrOrTypeFormat::genLiteralParser(StringRef value, FmtContext &ctx,
-                                        raw_ostream &os, unsigned indent) {
-  os.indent(indent) << "  // Parse literal '" << value << "'\n";
-  os.indent(indent) << tgfmt("  if ($_parser.parse", &ctx);
+                                        MethodBody &os) {
+  os << "// Parse literal '" << value << "'\n";
+  os << tgfmt("if ($_parser.parse", &ctx);
   if (value.front() == '_' || isalpha(value.front())) {
     os << "Keyword(\"" << value << "\")";
   } else {
     os << StringSwitch<StringRef>(value)
               .Case("->", "Arrow")
               .Case(":", "Colon")
               .Case(",", "Comma")
               .Case("=", "Equal")
               .Case("<", "Less")
               .Case(">", "Greater")
               .Case("{", "LBrace")
               .Case("}", "RBrace")
               .Case("(", "LParen")
               .Case(")", "RParen")
               .Case("[", "LSquare")
               .Case("]", "RSquare")
               .Case("?", "Question")
               .Case("+", "Plus")
               .Case("*", "Star")
        << "()";
   }
   os << ")\n";
   // Parser will emit an error
-  os.indent(indent) << "    return {};\n";
+  os << "  return {};\n";
 }
 
 void AttrOrTypeFormat::genVariableParser(const AttrOrTypeParameter &param,
-                                         FmtContext &ctx, raw_ostream &os,
-                                         unsigned indent) {
+                                         FmtContext &ctx, MethodBody &os) {
   /// Check for a custom parser. Use the default attribute parser otherwise.
   auto customParser = param.getParser();
   auto parser =
       customParser ? *customParser : StringRef(defaultParameterParser);
-  for (const char *line : variableParser) {
-    os.indent(indent) << formatv(line, param.getName(),
-                                 tgfmt(parser, &ctx, param.getCppStorageType()),
-                                 tgfmt(parseErrorStr, &ctx), def.getName(),
-                                 param.getCppType())
-                      << "\n";
-  }
+  os << formatv(variableParser, param.getName(),
+                tgfmt(parseErrorStr, &ctx), def.getName(), param.getCppType());
 }
 
 void AttrOrTypeFormat::genParamsParser(ParamsDirective *el, FmtContext &ctx,
-                                       raw_ostream &os) {
-  os << "  // Parse parameter list\n";
+                                       MethodBody &os) {
+  os << "// Parse parameter list\n";
   llvm::interleave(
       el->getParams(),
       [&](auto param) { this->genVariableParser(param, ctx, os); },
       [&]() { this->genLiteralParser(",", ctx, os); });
 }
 
 void AttrOrTypeFormat::genStructParser(StructDirective *el, FmtContext &ctx,
-                                       raw_ostream &os) {
-  os << "  // Parse parameter struct\n";
+                                       MethodBody &os) {
+  os << "// Parse parameter struct\n";
 
   /// Declare a "seen" variable for each key.
   for (const AttrOrTypeParameter &param : el->getParams())
-    os << formatv("  bool _seen_{0} = false;\n", param.getName());
+    os << formatv("bool _seen_{0} = false;\n", param.getName());
 
   /// Generate the parsing loop.
-  os << tgfmt(structParseLoopStart, &ctx, el->getNumParams());
-  genLiteralParser("=", ctx, os, 2);
-  os << "    ";
+  os.getStream().printReindented(
+      tgfmt(structParseLoopStart, &ctx, el->getNumParams()).str());
+  os.indent();
+  genLiteralParser("=", ctx, os);
   for (const AttrOrTypeParameter &param : el->getParams()) {
     os << formatv("if (!_seen_{0} && _paramKey == \"{0}\") {\n"
-                  "      _seen_{0} = true;\n",
+                  "  _seen_{0} = true;\n",
                   param.getName());
-    genVariableParser(param, ctx, os, 4);
-    os << "    } else ";
+    genVariableParser(param, ctx, os.indent());
+    os.unindent() << "} else ";
   }
+  os.unindent();
 
   /// Duplicate or unknown parameter.
-  os << formatv(structParseLoopEnd, tgfmt(parseErrorStr, &ctx),
-                el->getNumParams());
+  os.getStream().printReindented(strfmt(
+      structParseLoopEnd, tgfmt(parseErrorStr, &ctx), el->getNumParams()));
 
   /// Because the loop loops N times and each non-failing iteration sets 1 of
   /// N flags, successfully exiting the loop means that all parameters have been
   /// seen. `parseOptionalComma` would cause issues with any formats that use
   /// "struct(...) `,`" beacuse structs aren't sounded by braces.
 }
 
 //===----------------------------------------------------------------------===//
 // PrinterGen
 //===----------------------------------------------------------------------===//
 
-void AttrOrTypeFormat::genPrinter(raw_ostream &os) {
+void AttrOrTypeFormat::genPrinter(MethodBody &os) {
   FmtContext ctx;
   ctx.addSubst("_printer", "printer");
 
-  /// Generate the definition.
-  os << tgfmt(attrOrTypePrinterDefn, &ctx, def.getCppClassName());
-
   /// Generate printers.
   shouldEmitSpace = true;
   lastWasPunctuation = false;
   for (auto &el : elements)
     genElementPrinter(el.get(), ctx, os);
-
-  os << "}\n\n";
 }
 
 void AttrOrTypeFormat::genElementPrinter(Element *el, FmtContext &ctx,
-                                         raw_ostream &os) {
+                                         MethodBody &os) {
   if (auto *literal = dyn_cast<LiteralElement>(el))
     return genLiteralPrinter(literal->getSpelling(), ctx, os);
   if (auto *params = dyn_cast<ParamsDirective>(el))
     return genParamsPrinter(params, ctx, os);
   if (auto *strct = dyn_cast<StructDirective>(el))
     return genStructPrinter(strct, ctx, os);
   if (auto *var = dyn_cast<VariableElement>(el))
     return genVariablePrinter(var->getParam(), ctx, os);
 
   llvm_unreachable("unknown format element");
 }
 
 void AttrOrTypeFormat::genLiteralPrinter(StringRef value, FmtContext &ctx,
-                                         raw_ostream &os) {
+                                         MethodBody &os) {
   /// Don't insert a space before certain punctuation.
   bool needSpace =
       shouldEmitSpace && shouldEmitSpaceBefore(value, lastWasPunctuation);
   os << tgfmt("  $_printer$0 << \"$1\";\n", &ctx, needSpace ? " << ' '" : "",
               value);
 
   /// Update the flags.
   shouldEmitSpace =
       value.size() != 1 || !StringRef("<({[").contains(value.front());
   lastWasPunctuation = !(value.front() == '_' || isalpha(value.front()));
 }
 
 void AttrOrTypeFormat::genVariablePrinter(const AttrOrTypeParameter &param,
-                                          FmtContext &ctx, raw_ostream &os) {
+                                          FmtContext &ctx, MethodBody &os) {
   /// Insert a space before the next parameter, if necessary.
   if (shouldEmitSpace || !lastWasPunctuation)
     os << tgfmt("  $_printer << ' ';\n", &ctx);
   shouldEmitSpace = true;
   lastWasPunctuation = false;
 
   ctx.withSelf(getParameterAccessorName(param.getName()) + "()");
   os << "  ";
   if (auto printer = param.getPrinter())
     os << tgfmt(*printer, &ctx) << ";\n";
   else
     os << tgfmt(defaultParameterPrinter, &ctx) << ";\n";
 }
 
 void AttrOrTypeFormat::genParamsPrinter(ParamsDirective *el, FmtContext &ctx,
-                                        raw_ostream &os) {
+                                        MethodBody &os) {
   llvm::interleave(
       el->getParams(),
       [&](auto param) { this->genVariablePrinter(param, ctx, os); },
       [&]() { this->genLiteralPrinter(",", ctx, os); });
 }
 
 void AttrOrTypeFormat::genStructPrinter(StructDirective *el, FmtContext &ctx,
-                                        raw_ostream &os) {
+                                        MethodBody &os) {
   llvm::interleave(
       el->getParams(),
       [&](auto param) {
         this->genLiteralPrinter(param.getName(), ctx, os);
         this->genLiteralPrinter("=", ctx, os);
-        os << tgfmt("  $_printer << ' ';\n", &ctx);
         this->genVariablePrinter(param, ctx, os);
       },
       [&]() { this->genLiteralPrinter(",", ctx, os); });
 }
 
 //===----------------------------------------------------------------------===//
 // FormatParser
 //===----------------------------------------------------------------------===//
while (curToken.getKind() != FormatToken::eof) {
     if (failed(element))
       return failure();
 
     /// Add the format element and continue.
     elements.push_back(std::move(*element));
   }
 
   /// Check that all parameters have been seen.
-  SmallVector<AttrOrTypeParameter> params = getParameters(def);
-  for (auto it : llvm::enumerate(params)) {
+  for (auto &it : llvm::enumerate(def.getParameters())) {
     if (!seenParams.test(it.index())) {
       return emitError("format is missing reference to parameter: " +
                        it.value().getName());
     }
   }
 
   return AttrOrTypeFormat(def, std::move(elements));
 }

 }
 
 FailureOr<std::unique_ptr<Element>>
 FormatParser::parseVariable(ParserContext ctx) {
   /// Get the parameter name without the preceding "$".
   auto name = curToken.getSpelling().drop_front();
 
   /// Lookup the parameter.
-  SmallVector<AttrOrTypeParameter> params = getParameters(def);
+  ArrayRef<AttrOrTypeParameter> params = def.getParameters();
   auto *it = llvm::find_if(
       params, [&](auto &param) { return param.getName() == name; });
 
   /// Check that the parameter reference is valid.
   if (it == params.end())
     return emitError(def.getName() + " has no parameter named '" + name + "'");
   auto idx = std::distance(params.begin(), it);
   if (seenParams.test(idx))
FormatParser::parseDirective(ParserContext ctx) {
   default:
     return emitError("unknown directive in format: " + curToken.getSpelling());
   }
 }
 
 FailureOr<std::unique_ptr<Element>> FormatParser::parseParamsDirective() {
   consumeToken();
   /// Collect all of the attribute's or type's parameters.
-  SmallVector<AttrOrTypeParameter> params = getParameters(def);
   SmallVector<std::unique_ptr<Element>> vars;
   /// Ensure that none of the parameters have already been captured.
-  for (auto it : llvm::enumerate(params)) {
+  for (auto it : llvm::enumerate(def.getParameters())) {
     if (seenParams.test(it.index())) {
       return emitError("`params` captures duplicate parameter: " +
                        it.value().getName());
     }
     seenParams.set(it.index());
     vars.push_back(std::make_unique<VariableElement>(it.value()));
   }
   return {std::make_unique<ParamsDirective>(std::move(vars))};
FailureOr<std::unique_ptr<Element>> FormatParser::parseStructDirective() {
   return {std::make_unique<::StructDirective>(std::move(vars))};
 }
 
 //===----------------------------------------------------------------------===//
 // Interface
 //===----------------------------------------------------------------------===//
 
 void mlir::tblgen::generateAttrOrTypeFormat(const AttrOrTypeDef &def,
-                                            raw_ostream &os) {
+                                            MethodBody &parser,
+                                            MethodBody &printer) {
   llvm::SourceMgr mgr;
   mgr.AddNewSourceBuffer(
       llvm::MemoryBuffer::getMemBuffer(*def.getAssemblyFormat()),
       llvm::SMLoc());
 
   /// Parse the custom assembly format>
-  FormatParser parser(mgr, def);
-  FailureOr<AttrOrTypeFormat> format = parser.parse();
+  FormatParser fmtParser(mgr, def);
+  FailureOr<AttrOrTypeFormat> format = fmtParser.parse();
   if (failed(format)) {
     if (formatErrorIsFatal)
       PrintFatalError(def.getLoc(), "failed to parse assembly format");
     return;
   }
 
   /// Generate the parser and printer.
-  format->genParser(os);
-  format->genPrinter(os);
+  format->genParser(parser);
+  format->genPrinter(printer);
 }

mlir/tools/mlir-tblgen/OpClass.h

+//===- OpClass.h - Implementation of an Op Class --------------------------===//
+//
+// 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 MLIR_TOOLS_MLIRTBLGEN_OPCLASS_H_
+#define MLIR_TOOLS_MLIRTBLGEN_OPCLASS_H_
+
+#include "mlir/TableGen/Class.h"
+
+namespace mlir {
+namespace tblgen {
+
+/// Class for holding an op for C++ code emission. The class is specialized to
+/// add Op-specific declarations to the class.
+class OpClass : public Class {
+public:
+  /// Create an operation class with extra class declarations, whose default
+  /// visibility is public. Also declares at the top of the class:
+  ///
+  /// - inheritance of constructors from `Op`
+  /// - inheritance of `print`
+  /// - a type alias for the associated adaptor class
+  ///
+  OpClass(StringRef name, StringRef extraClassDeclaration);
+
+  /// Add an op trait.
+  void addTrait(Twine trait) { parent.addTemplateParam(trait.str()); }
+
+  /// The operation class is finalized by calling `Class::finalize` to delcare
+  /// all pending private and public methods (ops don't have custom constructors
+  /// or fields). Then, the extra class declarations are appended to the end of
+  /// the class declaration.
+  void finalize() override;
+
+private:
+  /// Hand-written extra class declarations.
+  StringRef extraClassDeclaration;
+  /// The parent class, which also contains the traits to be inherited.
+  ParentClass &parent;
+};
+
+} // end namespace tblgen
+} // end namespace mlir
+
+#endif // MLIR_TOOLS_MLIRTBLGEN_OPCLASS_H_

mlir/tools/mlir-tblgen/OpClass.cpp

+//===- OpClass.cpp - Implementation of an Op Class ------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "OpClass.h"
+
+using namespace mlir;
+using namespace mlir::tblgen;
+
+//===----------------------------------------------------------------------===//
+// OpClass definitions
+//===----------------------------------------------------------------------===//
+
+OpClass::OpClass(StringRef name, StringRef extraClassDeclaration)
+    : Class(name.str()), extraClassDeclaration(extraClassDeclaration),
+      parent(addParent("::mlir::Op")) {
+  parent.addTemplateParam(getClassName().str());
+  declare<VisibilityDeclaration>(Visibility::Public);
+  /// Inherit functions from Op.
+  declare<UsingDeclaration>("Op::Op");
+  declare<UsingDeclaration>("Op::print");
+  /// Type alias for the adaptor class.
+  declare<UsingDeclaration>("Adaptor", className + "Adaptor");
+}
+
+void OpClass::finalize() {
+  Class::finalize();
+  if (getLastVisibilityDecl() != Visibility::Public &&
+      !extraClassDeclaration.drop_while(std::isspace).startswith("public"))
+    declare<VisibilityDeclaration>(Visibility::Public);
+  declare<ExtraClassDeclaration>(extraClassDeclaration);
+}

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

 //===- OpDefinitionsGen.cpp - MLIR op definitions generator ---------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 // OpDefinitionsGen uses the description of operations to generate C++
 // definitions for ops.
 //
 //===----------------------------------------------------------------------===//
 
+#include "OpClass.h"
 #include "OpFormatGen.h"
 #include "OpGenHelpers.h"
 #include "mlir/TableGen/Class.h"
 #include "mlir/TableGen/CodeGenHelpers.h"
 #include "mlir/TableGen/Format.h"
 #include "mlir/TableGen/GenInfo.h"
 #include "mlir/TableGen/Interfaces.h"
 #include "mlir/TableGen/Operator.h"

 using namespace mlir;
 using namespace mlir::tblgen;
 
 static const char *const tblgenNamePrefix = "tblgen_";
 static const char *const generatedArgName = "odsArg";
 static const char *const odsBuilder = "odsBuilder";
 static const char *const builderOpState = "odsState";
 
-// Code for an Op to lookup an attribute. Uses cached identifiers.
-//
-// {0}: The attribute's getter name.
+/// Code for an Op to lookup an attribute. Uses cached identifiers.
+///
+/// {0}: The attribute's getter name.
 static const char *const opGetAttr = "(*this)->getAttr({0}AttrName())";
 
-// The logic to calculate the actual value range for a declared operand/result
-// of an op with variadic operands/results. Note that this logic is not for
-// general use; it assumes all variadic operands/results must have the same
-// number of values.
-//
-// {0}: The list of whether each declared operand/result is variadic.
-// {1}: The total number of non-variadic operands/results.
-// {2}: The total number of variadic operands/results.
-// {3}: The total number of actual values.
-// {4}: "operand" or "result".
+/// The logic to calculate the actual value range for a declared operand/result
+/// of an op with variadic operands/results. Note that this logic is not for
+/// general use; it assumes all variadic operands/results must have the same
+/// number of values.
+///
+/// {0}: The list of whether each declared operand/result is variadic.
+/// {1}: The total number of non-variadic operands/results.
+/// {2}: The total number of variadic operands/results.
+/// {3}: The total number of actual values.
+/// {4}: "operand" or "result".
 static const char *const sameVariadicSizeValueRangeCalcCode = R"(
   bool isVariadic[] = {{{0}};
   int prevVariadicCount = 0;
   for (unsigned i = 0; i < index; ++i)
     if (isVariadic[i]) ++prevVariadicCount;
 
   // Calculate how many dynamic values a static variadic {4} corresponds to.
   // This assumes all static variadic {4}s have the same dynamic value count.
   int variadicSize = ({3} - {1}) / {2};
   // `index` passed in as the parameter is the static index which counts each
   // {4} (variadic or not) as size 1. So here for each previous static variadic
   // {4}, we need to offset by (variadicSize - 1) to get where the dynamic
   // value pack for this static {4} starts.
   int start = index + (variadicSize - 1) * prevVariadicCount;
   int size = isVariadic[index] ? variadicSize : 1;
   return {{start, size};
 )";
 
-// The logic to calculate the actual value range for a declared operand/result
-// of an op with variadic operands/results. Note that this logic is assumes
-// the op has an attribute specifying the size of each operand/result segment
-// (variadic or not).
-//
-// {0}: The name of the attribute specifying the segment sizes.
+/// The logic to calculate the actual value range for a declared operand/result
+/// of an op with variadic operands/results. Note that this logic is assumes
+/// the op has an attribute specifying the size of each operand/result segment
+/// (variadic or not).
+///
+/// {0}: The name of the attribute specifying the segment sizes.
 static const char *const adapterSegmentSizeAttrInitCode = R"(
   assert(odsAttrs && "missing segment size attribute for op");
   auto sizeAttr = odsAttrs.get("{0}").cast<::mlir::DenseIntElementsAttr>();
 )";
 static const char *const opSegmentSizeAttrInitCode = R"(
   auto sizeAttr =
       (*this)->getAttr({0}AttrName()).cast<::mlir::DenseIntElementsAttr>();
 )";
 static const char *const attrSizedSegmentValueRangeCalcCode = R"(
   const uint32_t *sizeAttrValueIt = &*sizeAttr.value_begin<uint32_t>();
   if (sizeAttr.isSplat())
     return {*sizeAttrValueIt * index, *sizeAttrValueIt};
 
   unsigned start = 0;
   for (unsigned i = 0; i < index; ++i)
     start += sizeAttrValueIt[i];
   return {start, sizeAttrValueIt[index]};
 )";
-// The logic to calculate the actual value range for a declared operand
-// of an op with variadic of variadic operands within the OpAdaptor.
-//
-// {0}: The name of the segment attribute.
-// {1}: The index of the main operand.
+
+/// The logic to calculate the actual value range for a declared operand
+/// of an op with variadic of variadic operands within the OpAdaptor.
+///
+/// {0}: The name of the segment attribute.
+/// {1}: The index of the main operand.
 static const char *const variadicOfVariadicAdaptorCalcCode = R"(
   auto tblgenTmpOperands = getODSOperands({1});
   auto sizeAttrValues = {0}().getValues<uint32_t>();
   auto sizeAttrIt = sizeAttrValues.begin();
 
   ::llvm::SmallVector<::mlir::ValueRange> tblgenTmpOperandGroups;
   for (int i = 0, e = ::llvm::size(sizeAttrValues); i < e; ++i, ++sizeAttrIt) {{
     tblgenTmpOperandGroups.push_back(tblgenTmpOperands.take_front(*sizeAttrIt));
     tblgenTmpOperands = tblgenTmpOperands.drop_front(*sizeAttrIt);
   }
   return tblgenTmpOperandGroups;
 )";
 
-// The logic to build a range of either operand or result values.
-//
-// {0}: The begin iterator of the actual values.
-// {1}: The call to generate the start and length of the value range.
+/// The logic to build a range of either operand or result values.
+///
+/// {0}: The begin iterator of the actual values.
+/// {1}: The call to generate the start and length of the value range.
 static const char *const valueRangeReturnCode = R"(
   auto valueRange = {1};
   return {{std::next({0}, valueRange.first),
            std::next({0}, valueRange.first + valueRange.second)};
 )";
 
+/// A header for indicating code sections.
+///
+/// {0}: Some text, or a class name.
+/// {1}: Some text.
 static const char *const opCommentHeader = R"(
 //===----------------------------------------------------------------------===//
 // {0} {1}
 //===----------------------------------------------------------------------===//
 
 )";
 
 //===----------------------------------------------------------------------===//

 }
 
 void OpEmitter::emitDef(
     const Operator &op, raw_ostream &os,
     const StaticVerifierFunctionEmitter &staticVerifierEmitter) {
   OpEmitter(op, staticVerifierEmitter).emitDef(os);
 }
 
-void OpEmitter::emitDecl(raw_ostream &os) { opClass.writeDeclTo(os); }
+void OpEmitter::emitDecl(raw_ostream &os) {
+  opClass.finalize();
+  opClass.writeDeclTo(os);
+}
 
-void OpEmitter::emitDef(raw_ostream &os) { opClass.writeDefTo(os); }
+void OpEmitter::emitDef(raw_ostream &os) {
+  opClass.finalize();
+  opClass.writeDefTo(os);
+}
 
 static void errorIfPruned(size_t line, Method *m, const Twine &methodName,
                           const Operator &op) {
   if (m)
     return;
   PrintFatalError(op.getLoc(), "Unexpected overlap when generating `" +
                                    methodName + "` for " +
                                    op.getOperationName() + " (from line " +
if (attributeNames.empty()) {
       body << "};\n  return ::llvm::makeArrayRef(attrNames);";
     }
   }
   if (attributeNames.empty())
     return;
 
   // Emit the getAttributeNameForIndex methods.
   {
-    auto *method = opClass.addInlineMethod<Method::MP_Private>(
+    auto *method = opClass.addInlineMethod<Method::Private>(
         "::mlir::Identifier", "getAttributeNameForIndex",
         MethodParameter("unsigned", "index"));
     ERROR_IF_PRUNED(method, "getAttributeNameForIndex", op);
     method->body()
         << "  return getAttributeNameForIndex((*this)->getName(), index);";
   }
   {
-    auto *method = opClass.addStaticInlineMethod<Method::MP_Private>(
+    auto *method = opClass.addStaticInlineMethod<Method::Private>(
         "::mlir::Identifier", "getAttributeNameForIndex",
         MethodParameter("::mlir::OperationName", "name"),
         MethodParameter("unsigned", "index"));
     ERROR_IF_PRUNED(method, "getAttributeNameForIndex", op);
-    method->body() << "assert(index < " << attributeNames.size()
-                   << " && \"invalid attribute index\");\n"
-                      "  return name.getAbstractOperation()"
-                      "->getAttributeNames()[index];";
+
+    const char *const getAttrName = R"(
+  assert(index < {0} && "invalid attribute index");
+  return name.getAbstractOperation()->getAttributeNames()[index];
+)";
+    method->body() << formatv(getAttrName, attributeNames.size());
   }
 
   // Generate the <attr>AttrName methods, that expose the attribute names to
   // users.
   const char *attrNameMethodBody = "  return getAttributeNameForIndex({0});";
   for (const std::pair<StringRef, unsigned> &attrIt : attributeNames) {
     for (StringRef name : op.getGetterNames(attrIt.first)) {
       std::string methodName = (name + "AttrName").str();
 
       // Generate the non-static variant.
       {
         auto *method =
             opClass.addInlineMethod("::mlir::Identifier", methodName);
         ERROR_IF_PRUNED(method, methodName, op);
-        method->body()
-            << llvm::formatv(attrNameMethodBody, attrIt.second).str();
+        method->body() << llvm::formatv(attrNameMethodBody, attrIt.second);
       }
 
       // Generate the static variant.
       {
         auto *method = opClass.addStaticInlineMethod(
             "::mlir::Identifier", methodName,
             MethodParameter("::mlir::OperationName", "name"));
         ERROR_IF_PRUNED(method, methodName, op);
         method->body() << llvm::formatv(attrNameMethodBody,
-                                        "name, " + Twine(attrIt.second))
-                              .str();
+                                        "name, " + Twine(attrIt.second));
       }
     }
   }
 }
 
 void OpEmitter::genAttrGetters() {
   FmtContext fctx;
   fctx.withBuilder("::mlir::Builder((*this)->getContext())");
body << "  return "
          << tgfmt(attr.getConvertFromStorageCall(), &fctx.withSelf("attr"))
          << ";\n";
   };
 
   // Generate named accessor with Attribute return type. This is a wrapper class
   // that allows referring to the attributes via accessors instead of having to
   // use the string interface for better compile time verification.
   auto emitAttrWithStorageType = [&](StringRef name, Attribute attr) {
-    auto *method =
-        opClass.addMethod(attr.getStorageType(), (name + "Attr").str());
+    auto *method = opClass.addMethod(attr.getStorageType(), name + "Attr");
     if (!method)
       return;
     method->body() << formatv(
         "  return {0}.{1}<{2}>();", formatv(opGetAttr, name),
         attr.isOptional() || attr.hasDefaultValue() ? "dyn_cast_or_null"
                                                     : "cast",
         attr.getStorageType());
   };

 
 void OpEmitter::genAttrSetters() {
   // Generate raw named setter type. This is a wrapper class that allows setting
   // to the attributes via setters instead of having to use the string interface
   // for better compile time verification.
   auto emitAttrWithStorageType = [&](StringRef setterName, StringRef getterName,
                                      Attribute attr) {
     auto *method =
-        opClass.addMethod("void", (setterName + "Attr").str(),
+        opClass.addMethod("void", setterName + "Attr",
                           MethodParameter(attr.getStorageType(), "attr"));
     if (method)
       method->body() << formatv("  (*this)->setAttr({0}AttrName(), attr);",
                                 getterName);
   };
 
   for (const NamedAttribute &namedAttr : op.getAttributes()) {
     if (namedAttr.attr.isDerivedAttr())
       continue;
     for (auto names : llvm::zip(op.getSetterNames(namedAttr.name),
                                 op.getGetterNames(namedAttr.name)))
       emitAttrWithStorageType(std::get<0>(names), std::get<1>(names),
                               namedAttr.attr);
   }
 }
 
 void OpEmitter::genOptionalAttrRemovers() {
   // Generate methods for removing optional attributes, instead of having to
   // use the string interface. Enables better compile time verification.
   auto emitRemoveAttr = [&](StringRef name) {
     auto upperInitial = name.take_front().upper();
     auto suffix = name.drop_front();
-    auto *method = opClass.addMethod(
-        "::mlir::Attribute", ("remove" + upperInitial + suffix + "Attr").str());
+    auto *method = opClass.addMethod("::mlir::Attribute",
+                                     "remove" + upperInitial + suffix + "Attr");
     if (!method)
       return;
     method->body() << formatv("  return (*this)->removeAttr({0}AttrName());",
                               op.getGetterName(name));
   };
 
   for (const NamedAttribute &namedAttr : op.getAttributes())
     if (namedAttr.attr.isOptional())

 }
 
 void OpEmitter::genBuilder() {
   // Handle custom builders if provided.
   for (const Builder &builder : op.getBuilders()) {
     SmallVector<MethodParameter> arguments = getBuilderSignature(builder);
 
     Optional<StringRef> body = builder.getBody();
-    Method::Property properties =
-        body ? Method::MP_Static : Method::MP_StaticDeclaration;
+    auto properties = body ? Method::Static : Method::StaticDeclaration;
     auto *method =
         opClass.addMethod("void", "build", properties, std::move(arguments));
     if (body)
       ERROR_IF_PRUNED(method, "build", op);
 
     FmtContext fctx;
     fctx.withBuilder(odsBuilder);
     fctx.addSubst("_state", builderOpState);
for (int i = 0, e = op.getNumArgs(), numOperands = 0; i < e; ++i) {
     }
 
     // Attach default value if requested and possible.
     std::string defaultValue;
     if (attrParamKind == AttrParamKind::UnwrappedValue &&
         i >= defaultValuedAttrStartIndex) {
       defaultValue += attr.getDefaultValue();
     }
-    paramList.emplace_back(type, namedAttr.name, defaultValue,
+    paramList.emplace_back(type, namedAttr.name, StringRef(defaultValue),
                            attr.isOptional());
   }
 
   /// Insert parameters for each successor.
   for (const NamedSuccessor &succ : op.getSuccessors()) {
     StringRef type =
         succ.isVariadic() ? "::mlir::BlockRange" : "::mlir::Block *";
     paramList.emplace_back(type, succ.name);
void OpEmitter::genCanonicalizerDecls() {
   // method, but not implementing 'getCanonicalizationPatterns' manually.
   bool hasBody = hasCanonicalizeMethod && !hasCanonicalizer;
 
   // Add a signature for getCanonicalizationPatterns if implemented by the
   // dialect or if synthesized to call 'canonicalize'.
   SmallVector<MethodParameter> paramList;
   paramList.emplace_back("::mlir::RewritePatternSet &", "results");
   paramList.emplace_back("::mlir::MLIRContext *", "context");
-  auto kind = hasBody ? Method::MP_Static : Method::MP_StaticDeclaration;
+  auto kind = hasBody ? Method::Static : Method::StaticDeclaration;
   auto *method = opClass.addMethod("void", "getCanonicalizationPatterns", kind,
                                    std::move(paramList));
 
   // If synthesizing the method, fill it it.
   if (hasBody) {
     ERROR_IF_PRUNED(method, "getCanonicalizationPatterns", op);
     method->body() << "  results.add(canonicalize);\n";
   }

 }
 
 Method *OpEmitter::genOpInterfaceMethod(const InterfaceMethod &method,
                                         bool declaration) {
   SmallVector<MethodParameter> paramList;
   for (const InterfaceMethod::Argument &arg : method.getArguments())
     paramList.emplace_back(arg.type, arg.name);
 
-  auto properties = method.isStatic() ? Method::MP_Static : Method::MP_None;
-  if (declaration)
-    properties =
-        static_cast<Method::Property>(properties | Method::MP_Declaration);
-  return opClass.addMethod(method.getReturnType(), method.getName(), properties,
+  auto props = (Method::Static & method.isStatic()) |
+               (Method::Declaration & declaration);
+  return opClass.addMethod(method.getReturnType(), method.getName(), props,
                            std::move(paramList));
 }
 
 void OpEmitter::genOpInterfaceMethods() {
   for (const auto &trait : op.getTraits()) {
     if (const auto *opTrait = dyn_cast<tblgen::InterfaceTrait>(&trait))
       if (opTrait->shouldDeclareMethods())
         genOpInterfaceMethods(opTrait);
   }
 }
 
 void OpEmitter::genSideEffectInterfaceMethods() {
   enum EffectKind { Operand, Result, Symbol, Static };
   struct EffectLocation {
     /// The effect applied.
     SideEffect effect;
 
     /// The index if the kind is not static.
-    unsigned index : 30;
+    unsigned index;
 
     /// The kind of the location.
-    unsigned kind : 2;
+    unsigned kind;
   };
 
   StringMap<SmallVector<EffectLocation, 1>> interfaceEffects;
   auto resolveDecorators = [&](Operator::var_decorator_range decorators,
                                unsigned index, unsigned kind) {
     for (auto decorator : decorators)
       if (SideEffect *effect = dyn_cast<SideEffect>(&decorator)) {
         opClass.addTrait(effect->getInterfaceTrait());
const auto canSkip = [](const NamedSuccessor &successor) {
     return successor.constraint.getPredicate().isNull();
   };
   auto successors = op.getSuccessors();
   if (successors.empty() && llvm::all_of(successors, canSkip))
     return;
 
   body << "  {\n    unsigned index = 0; (void)index;\n";
 
-  for (auto it : llvm::enumerate(successors)) {
+  for (auto &it : llvm::enumerate(successors)) {
     const auto &successor = it.value();
     if (canSkip(successor))
       continue;
 
     auto getSuccessor =
         formatv(successor.isVariadic() ? "{0}()" : getSingleSuccessor,
                 successor.name, it.index())
             .str();
for (const auto &trait : op.getTraits()) {
     if (auto *opTrait = dyn_cast<tblgen::NativeTrait>(&trait))
       opClass.addTrait(opTrait->getFullyQualifiedTraitName());
     else if (auto *opTrait = dyn_cast<tblgen::InterfaceTrait>(&trait))
       opClass.addTrait(opTrait->getFullyQualifiedTraitName());
   }
 }
 
 void OpEmitter::genOpNameGetter() {
-  auto *method = opClass.addStaticMethod<Method::MP_Constexpr>(
+  auto *method = opClass.addStaticMethod<Method::Constexpr>(
       "::llvm::StringLiteral", "getOperationName");
   ERROR_IF_PRUNED(method, "getOperationName", op);
   method->body() << "  return ::llvm::StringLiteral(\"" << op.getOperationName()
                  << "\");";
 }
 
 void OpEmitter::genOpAsmInterface() {
   // If the user only has one results or specifically added the Asm trait,
private:
   StaticVerifierFunctionEmitter &staticVerifierEmitter;
 };
 } // end anonymous namespace
 
 OpOperandAdaptorEmitter::OpOperandAdaptorEmitter(
     const Operator &op, StaticVerifierFunctionEmitter &staticVerifierEmitter)
     : op(op), adaptor(op.getAdaptorName()),
       staticVerifierEmitter(staticVerifierEmitter) {
-  adaptor.newField("::mlir::ValueRange", "odsOperands");
-  adaptor.newField("::mlir::DictionaryAttr", "odsAttrs");
-  adaptor.newField("::mlir::RegionRange", "odsRegions");
+  adaptor.addField("::mlir::ValueRange", "odsOperands");
+  adaptor.addField("::mlir::DictionaryAttr", "odsAttrs");
+  adaptor.addField("::mlir::RegionRange", "odsRegions");
   const auto *attrSizedOperands =
-      op.getTrait("::mlir::OpTrait::AttrSizedOperandSegments");
+      op.getTrait("::m::OpTrait::AttrSizedOperandSegments");
   {
     SmallVector<MethodParameter> paramList;
     paramList.emplace_back("::mlir::ValueRange", "values");
     paramList.emplace_back("::mlir::DictionaryAttr", "attrs",
                            attrSizedOperands ? "" : "nullptr");
     paramList.emplace_back("::mlir::RegionRange", "regions", "{}");
-    auto *constructor = adaptor.addConstructorAndPrune(std::move(paramList));
+    auto *constructor = adaptor.addConstructor(std::move(paramList));
 
     constructor->addMemberInitializer("odsOperands", "values");
     constructor->addMemberInitializer("odsAttrs", "attrs");
     constructor->addMemberInitializer("odsRegions", "regions");
   }
 
   {
-    auto *constructor = adaptor.addConstructorAndPrune(
+    auto *constructor = adaptor.addConstructor(
         MethodParameter(op.getCppClassName() + " &", "op"));
     constructor->addMemberInitializer("odsOperands", "op->getOperands()");
     constructor->addMemberInitializer("odsAttrs", "op->getAttrDictionary()");
     constructor->addMemberInitializer("odsRegions", "op->getRegions()");
   }
 
   {
     auto *m = adaptor.addMethod("::mlir::ValueRange", "getOperands");
for (StringRef name : op.getGetterNames(region.name)) {
       auto *m = adaptor.addMethod("::mlir::Region &", name);
       ERROR_IF_PRUNED(m, "Adaptor::" + name, op);
       m->body() << formatv("  return *odsRegions[{0}];", i);
     }
   }
 
   // Add verification function.
   addVerification();
+  adaptor.finalize();
 }
 
 void OpOperandAdaptorEmitter::addVerification() {
   auto *method = adaptor.addMethod("::mlir::LogicalResult", "verify",
                                    MethodParameter("::mlir::Location", "loc"));
   ERROR_IF_PRUNED(method, "verify", op);
   auto &body = method->body();
 

mlir/tools/mlir-tblgen/OpDocGen.cpp

 // Emit the description by aligning the text to the left per line (e.g.,
 // removing the minimum indentation across the block).
 //
 // This expects that the description in the tablegen file is already formatted
 // in a way the user wanted but has some additional indenting due to being
 // nested in the op definition.
 void mlir::tblgen::emitDescription(StringRef description, raw_ostream &os) {
   raw_indented_ostream ros(os);
-  ros.reindent(description.rtrim(" \t"));
+  ros.printReindented(description.rtrim(" \t"));
 }
 
 // Emits `str` with trailing newline if not empty.
 static void emitIfNotEmpty(StringRef str, raw_ostream &os) {
   if (!str.empty()) {
     emitDescription(str, os);
     os << "\n";
   }

 }
 
 //===----------------------------------------------------------------------===//
 // TypeDef Documentation
 //===----------------------------------------------------------------------===//
 
 static void emitAttrOrTypeDefAssemblyFormat(const AttrOrTypeDef &def,
                                             raw_ostream &os) {
-  SmallVector<AttrOrTypeParameter, 4> parameters;
-  def.getParameters(parameters);
+  ArrayRef<AttrOrTypeParameter> parameters = def.getParameters();
   if (parameters.empty()) {
     os << "\nSyntax: `!" << def.getDialect().getName() << "."
        << def.getMnemonic() << "`\n";
     return;
   }
 
   os << "\nSyntax:\n\n```\n!" << def.getDialect().getName() << "."
      << def.getMnemonic() << "<\n";
static void emitAttrOrTypeDefDoc(const AttrOrTypeDef &def, raw_ostream &os) {
 
   // Emit the description if present.
   if (def.hasDescription()) {
     os << "\n";
     mlir::tblgen::emitDescription(def.getDescription(), os);
   }
 
   // Emit parameter documentation.
-  SmallVector<AttrOrTypeParameter, 4> parameters;
-  def.getParameters(parameters);
+  ArrayRef<AttrOrTypeParameter> parameters = def.getParameters();
   if (!parameters.empty()) {
     os << "\n#### Parameters:\n\n";
     os << "| Parameter | C++ type | Description |\n"
        << "| :-------: | :-------: | ----------- |\n";
     for (const auto &it : parameters) {
       auto desc = it.getSummary();
       os << "| " << it.getName() << " | `" << it.getCppType() << "` | "
          << (desc ? *desc : "") << " |\n";

mlir/tools/mlir-tblgen/OpFormatGen.cpp

 //===- OpFormatGen.cpp - MLIR operation asm format generator --------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "OpFormatGen.h"
 #include "FormatGen.h"
+#include "OpClass.h"
 #include "mlir/Support/LogicalResult.h"
 #include "mlir/TableGen/Class.h"
 #include "mlir/TableGen/Format.h"
 #include "mlir/TableGen/GenInfo.h"
 #include "mlir/TableGen/Interfaces.h"
 #include "mlir/TableGen/Operator.h"
 #include "mlir/TableGen/Trait.h"
 #include "llvm/ADT/MapVector.h"

mlir/tools/mlir-tblgen/RewriterGen.cpp

void PatternEmitter::emit(StringRef rewriteName) {
   llvm::interleaveComma(sortedResultOps, os, [&](const Operator *op) {
     os << '"' << op->getOperationName() << '"';
   });
   os << "}) {}\n";
 
   // Emit matchAndRewrite() function.
   {
     auto classScope = os.scope();
-    os.reindent(R"(
+    os.printReindented(R"(
     ::mlir::LogicalResult matchAndRewrite(::mlir::Operation *op0,
         ::mlir::PatternRewriter &rewriter) const override {)")
         << '\n';
     {
       auto functionScope = os.scope();
 
       // Register all symbols bound in the source pattern.
       pattern.collectSourcePatternBoundSymbols(symbolInfoMap);

mlir/unittests/Support/IndentedOstreamTest.cpp

TEST(FormatTest, Reindent) {
   const auto *desc = R"(
        
        
          First line
                  second line
                  
                  
   )";
-  ros.reindent(desc);
+  ros.printReindented(desc);
   ros.flush();
   const auto *expected =
       R"(First line
         second line
 
 
 )";
   EXPECT_THAT(os.str(), StrEq(expected));
 }