tools/mlir-tblgen/OpInterfacesGen.cpp

//===- OpInterfacesGen.cpp - MLIR op interface utility 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
//
//===----------------------------------------------------------------------===//
//
// OpInterfacesGen generates definitions for operation interfaces.
//
//===----------------------------------------------------------------------===//

#include "DocGenUtilities.h"
#include "mlir/TableGen/Format.h"
#include "mlir/TableGen/GenInfo.h"
#include "mlir/TableGen/Interfaces.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"

using namespace mlir;
using mlir::tblgen::Interface;
using mlir::tblgen::InterfaceMethod;
using mlir::tblgen::OpInterface;

/// Emit a string corresponding to a C++ type, followed by a space if necessary.
static raw_ostream &emitCPPType(StringRef type, raw_ostream &os) {
  type = type.trim();
  os << type;
  if (type.back() != '&' && type.back() != '*')
    os << " ";
  return os;
}

/// Emit the method name and argument list for the given method. If 'addThisArg'
/// is true, then an argument is added to the beginning of the argument list for
/// the concrete value.
static void emitMethodNameAndArgs(const InterfaceMethod &method,
                                  raw_ostream &os, StringRef valueType,
                                  bool addThisArg, bool addConst) {
  os << method.getName() << '(';
  if (addThisArg) {
    if (addConst)
      os << "const ";
    os << "const Concept *impl, ";
    emitCPPType(valueType, os)
        << "tablegen_opaque_val" << (method.arg_empty() ? "" : ", ");
  }
  llvm::interleaveComma(method.getArguments(), os,
                        [&](const InterfaceMethod::Argument &arg) {
                          os << arg.type << " " << arg.name;
                        });
  os << ')';
  if (addConst)
    os << " const";
}

/// Get an array of all OpInterface definitions but exclude those subclassing
/// "DeclareOpInterfaceMethods".
static std::vector<llvm::Record *>
getAllOpInterfaceDefinitions(const llvm::RecordKeeper &recordKeeper) {
  std::vector<llvm::Record *> defs =
      recordKeeper.getAllDerivedDefinitions("OpInterface");

  llvm::erase_if(defs, [](const llvm::Record *def) {
    return def->isSubClassOf("DeclareOpInterfaceMethods");
  });
  return defs;
}

namespace {
/// This struct is the base generator used when processing tablegen interfaces.
class InterfaceGenerator {
public:
  bool emitInterfaceDefs();
  bool emitInterfaceDecls();
  bool emitInterfaceDocs();

protected:
  InterfaceGenerator(std::vector<llvm::Record *> &&defs, raw_ostream &os)
      : defs(std::move(defs)), os(os) {}

  void emitConceptDecl(Interface &interface);
  void emitModelDecl(Interface &interface);
  void emitModelMethodsDef(Interface &interface);
  void emitTraitDecl(Interface &interface, StringRef interfaceName,
                     StringRef interfaceTraitsName);
  void emitInterfaceDecl(Interface interface);

  /// The set of interface records to emit.
  std::vector<llvm::Record *> defs;
  // The stream to emit to.
  raw_ostream &os;
  /// The C++ value type of the interface, e.g. Operation*.
  StringRef valueType;
  /// The C++ base interface type.
  StringRef interfaceBaseType;
  /// The name of the typename for the value template.
  StringRef valueTemplate;
  /// The format context to use for methods.
  tblgen::FmtContext nonStaticMethodFmt;
  tblgen::FmtContext traitMethodFmt;
};

/// A specialized generator for attribute interfaces.
struct AttrInterfaceGenerator : public InterfaceGenerator {
  AttrInterfaceGenerator(const llvm::RecordKeeper &records, raw_ostream &os)
      : InterfaceGenerator(records.getAllDerivedDefinitions("AttrInterface"),
                           os) {
    valueType = "::mlir::Attribute";
    interfaceBaseType = "AttributeInterface";
    valueTemplate = "ConcreteAttr";
    StringRef castCode = "(tablegen_opaque_val.cast<ConcreteAttr>())";
    nonStaticMethodFmt.addSubst("_attr", castCode).withSelf(castCode);
    traitMethodFmt.addSubst("_attr",
                            "(*static_cast<const ConcreteAttr *>(this))");
  }
};
/// A specialized generator for operation interfaces.
struct OpInterfaceGenerator : public InterfaceGenerator {
  OpInterfaceGenerator(const llvm::RecordKeeper &records, raw_ostream &os)
      : InterfaceGenerator(getAllOpInterfaceDefinitions(records), os) {
    valueType = "::mlir::Operation *";
    interfaceBaseType = "OpInterface";
    valueTemplate = "ConcreteOp";
    StringRef castCode = "(llvm::cast<ConcreteOp>(tablegen_opaque_val))";
    nonStaticMethodFmt.addSubst("_this", "impl")
        .withOp(castCode)
        .withSelf(castCode);
    traitMethodFmt.withOp("(*static_cast<ConcreteOp *>(this))");
  }
};
/// A specialized generator for type interfaces.
struct TypeInterfaceGenerator : public InterfaceGenerator {
  TypeInterfaceGenerator(const llvm::RecordKeeper &records, raw_ostream &os)
      : InterfaceGenerator(records.getAllDerivedDefinitions("TypeInterface"),
                           os) {
    valueType = "::mlir::Type";
    interfaceBaseType = "TypeInterface";
    valueTemplate = "ConcreteType";
    StringRef castCode = "(tablegen_opaque_val.cast<ConcreteType>())";
    nonStaticMethodFmt.addSubst("_type", castCode).withSelf(castCode);
    traitMethodFmt.addSubst("_type",
                            "(*static_cast<const ConcreteType *>(this))");
  }
};
} // end anonymous namespace

//===----------------------------------------------------------------------===//
// GEN: Interface definitions
//===----------------------------------------------------------------------===//

static void emitInterfaceDef(Interface interface, StringRef valueType,
                             raw_ostream &os) {
  StringRef interfaceName = interface.getName();
  StringRef cppNamespace = interface.getCppNamespace();
  cppNamespace.consume_front("::");

  // Insert the method definitions.
  bool isOpInterface = isa<OpInterface>(interface);
  for (auto &method : interface.getMethods()) {
    emitCPPType(method.getReturnType(), os);
    if (!cppNamespace.empty())
      os << cppNamespace << "::";
    os << interfaceName << "::";
    emitMethodNameAndArgs(method, os, valueType, /*addThisArg=*/false,
                          /*addConst=*/!isOpInterface);

    // Forward to the method on the concrete operation type.
    os << " {\n      return getImpl()->" << method.getName() << '(';
    if (!method.isStatic()) {
      os << "getImpl(), ";
      os << (isOpInterface ? "getOperation()" : "*this");
      os << (method.arg_empty() ? "" : ", ");
    }
    llvm::interleaveComma(
        method.getArguments(), os,
        [&](const InterfaceMethod::Argument &arg) { os << arg.name; });
    os << ");\n  }\n";
  }
}

bool InterfaceGenerator::emitInterfaceDefs() {
  llvm::emitSourceFileHeader("Interface Definitions", os);

  for (const auto *def : defs)
    emitInterfaceDef(Interface(def), valueType, os);
  return false;
}

//===----------------------------------------------------------------------===//
// GEN: Interface declarations
//===----------------------------------------------------------------------===//

void InterfaceGenerator::emitConceptDecl(Interface &interface) {
  os << "  struct Concept {\n";

  // Insert each of the pure virtual concept methods.
  for (auto &method : interface.getMethods()) {
    os << "    ";
    emitCPPType(method.getReturnType(), os);
    os << "(*" << method.getName() << ")(";
    if (!method.isStatic()) {
      os << "const Concept *impl, ";
      emitCPPType(valueType, os) << (method.arg_empty() ? "" : ", ");
    }
    llvm::interleaveComma(
        method.getArguments(), os,
        [&](const InterfaceMethod::Argument &arg) { os << arg.type; });
    os << ");\n";
  }
  os << "  };\n";
}

void InterfaceGenerator::emitModelDecl(Interface &interface) {
  // Emit the basic model and the fallback model.
  for (const char *modelClass : {"Model", "FallbackModel"}) {
    os << "  template<typename " << valueTemplate << ">\n";
    os << "  class " << modelClass << " : public Concept {\n  public:\n";
    os << "    using Interface = " << interface.getCppNamespace()
       << (interface.getCppNamespace().empty() ? "" : "::")
       << interface.getName() << ";\n";
    os << "    " << modelClass << "() : Concept{";
    llvm::interleaveComma(
        interface.getMethods(), os,
        [&](const InterfaceMethod &method) { os << method.getName(); });
    os << "} {}\n\n";

    // Insert each of the virtual method overrides.
    for (auto &method : interface.getMethods()) {
      emitCPPType(method.getReturnType(), os << "    static inline ");
      emitMethodNameAndArgs(method, os, valueType,
                            /*addThisArg=*/!method.isStatic(),
                            /*addConst=*/false);
      os << ";\n";
    }
    os << "  };\n";
  }

  // Emit the template for the external model.
  os << "  template<typename ConcreteModel, typename " << valueTemplate
     << ">\n";
  os << "  class ExternalModel : public FallbackModel<ConcreteModel> {\n";
  os << "  public:\n";

  // Emit declarations for methods that have default implementations. Other
  // methods are expected to be implemented by the concrete derived model.
  for (auto &method : interface.getMethods()) {
    if (!method.getDefaultImplementation())
      continue;
    os << "    ";
    if (method.isStatic())
      os << "static ";
    emitCPPType(method.getReturnType(), os);
    os << method.getName() << "(";
    if (!method.isStatic()) {
      emitCPPType(valueType, os);
      os << "tablegen_opaque_val";
      if (!method.arg_empty())
        os << ", ";
    }
    llvm::interleaveComma(method.getArguments(), os,
                          [&](const InterfaceMethod::Argument &arg) {
                            emitCPPType(arg.type, os);
                            os << arg.name;
                          });
    os << ")";
    if (!method.isStatic())
      os << " const";
    os << ";\n";
  }
  os << "  };\n";
}

void InterfaceGenerator::emitModelMethodsDef(Interface &interface) {
  for (auto &method : interface.getMethods()) {
    os << "template<typename " << valueTemplate << ">\n";
    emitCPPType(method.getReturnType(), os);
    os << "detail::" << interface.getName() << "InterfaceTraits::Model<"
       << valueTemplate << ">::";
    emitMethodNameAndArgs(method, os, valueType,
                          /*addThisArg=*/!method.isStatic(),
                          /*addConst=*/false);
    os << " {\n  ";

    // Check for a provided body to the function.
    if (Optional<StringRef> body = method.getBody()) {
      if (method.isStatic())
        os << body->trim();
      else
        os << tblgen::tgfmt(body->trim(), &nonStaticMethodFmt);
      os << "\n}\n";
      continue;
    }

    // Forward to the method on the concrete operation type.
    if (method.isStatic())
      os << "return " << valueTemplate << "::";
    else
      os << tblgen::tgfmt("return $_self.", &nonStaticMethodFmt);

    // Add the arguments to the call.
    os << method.getName() << '(';
    llvm::interleaveComma(
        method.getArguments(), os,
        [&](const InterfaceMethod::Argument &arg) { os << arg.name; });
    os << ");\n}\n";
  }

  for (auto &method : interface.getMethods()) {
    os << "template<typename " << valueTemplate << ">\n";
    emitCPPType(method.getReturnType(), os);
    os << "detail::" << interface.getName() << "InterfaceTraits::FallbackModel<"
       << valueTemplate << ">::";
    emitMethodNameAndArgs(method, os, valueType,
                          /*addThisArg=*/!method.isStatic(),
                          /*addConst=*/false);
    os << " {\n  ";

    // Forward to the method on the concrete Model implementation.
    if (method.isStatic())
      os << "return " << valueTemplate << "::";
    else
      os << "return static_cast<const " << valueTemplate << " *>(impl)->";

    // Add the arguments to the call.
    os << method.getName() << '(';
    if (!method.isStatic())
      os << "tablegen_opaque_val" << (method.arg_empty() ? "" : ", ");
    llvm::interleaveComma(
        method.getArguments(), os,
        [&](const InterfaceMethod::Argument &arg) { os << arg.name; });
    os << ");\n}\n";
  }

  // Emit default implementations for the external model.
  for (auto &method : interface.getMethods()) {
    if (!method.getDefaultImplementation())
      continue;
    os << "template<typename ConcreteModel, typename " << valueTemplate
       << ">\n";
    emitCPPType(method.getReturnType(), os);
    os << "detail::" << interface.getName()
       << "InterfaceTraits::ExternalModel<ConcreteModel, " << valueTemplate
       << ">::";

    os << method.getName() << "(";
    if (!method.isStatic()) {
      emitCPPType(valueType, os);
      os << "tablegen_opaque_val";
      if (!method.arg_empty())
        os << ", ";
    }
    llvm::interleaveComma(method.getArguments(), os,
                          [&](const InterfaceMethod::Argument &arg) {
                            emitCPPType(arg.type, os);
                            os << arg.name;
                          });
    os << ")";
    if (!method.isStatic())
      os << " const";

    os << " {\n";

    // Use the empty context for static methods.
    tblgen::FmtContext ctx;
    os << tblgen::tgfmt(method.getDefaultImplementation()->trim(),
                        method.isStatic() ? &ctx : &nonStaticMethodFmt);
    os << "\n}\n";
  }
}

void InterfaceGenerator::emitTraitDecl(Interface &interface,
                                       StringRef interfaceName,
                                       StringRef interfaceTraitsName) {
  os << llvm::formatv("  template <typename {3}>\n"
                      "  struct {0}Trait : public ::mlir::{2}<{0},"
                      " detail::{1}>::Trait<{3}> {{\n",
                      interfaceName, interfaceTraitsName, interfaceBaseType,
                      valueTemplate);

  // Insert the default implementation for any methods.
  bool isOpInterface = isa<OpInterface>(interface);
  for (auto &method : interface.getMethods()) {
    // Flag interface methods named verifyTrait.
    if (method.getName() == "verifyTrait")
      PrintFatalError(
          formatv("'verifyTrait' method cannot be specified as interface "
                  "method for '{0}'; use the 'verify' field instead",
                  interfaceName));
    auto defaultImpl = method.getDefaultImplementation();
    if (!defaultImpl)
      continue;

    os << "    " << (method.isStatic() ? "static " : "");
    emitCPPType(method.getReturnType(), os);
    emitMethodNameAndArgs(method, os, valueType, /*addThisArg=*/false,
                          /*addConst=*/!isOpInterface && !method.isStatic());
    os << " {\n      " << tblgen::tgfmt(defaultImpl->trim(), &traitMethodFmt)
       << "\n    }\n";
  }

  if (auto verify = interface.getVerify()) {
    assert(isa<OpInterface>(interface) && "only OpInterface supports 'verify'");

    tblgen::FmtContext verifyCtx;
    verifyCtx.withOp("op");
    os << "    static ::mlir::LogicalResult verifyTrait(::mlir::Operation *op) "
          "{\n      "
       << tblgen::tgfmt(verify->trim(), &verifyCtx) << "\n    }\n";
  }
  if (auto extraTraitDecls = interface.getExtraTraitClassDeclaration())
    os << tblgen::tgfmt(*extraTraitDecls, &traitMethodFmt) << "\n";

  os << "  };\n";
}

void InterfaceGenerator::emitInterfaceDecl(Interface interface) {
  llvm::SmallVector<StringRef, 2> namespaces;
  llvm::SplitString(interface.getCppNamespace(), namespaces, "::");
  for (StringRef ns : namespaces)
    os << "namespace " << ns << " {\n";

  StringRef interfaceName = interface.getName();
  auto interfaceTraitsName = (interfaceName + "InterfaceTraits").str();

  // Emit a forward declaration of the interface class so that it becomes usable
  // in the signature of its methods.
  os << "class " << interfaceName << ";\n";

  // Emit the traits struct containing the concept and model declarations.
  os << "namespace detail {\n"
     << "struct " << interfaceTraitsName << " {\n";
  emitConceptDecl(interface);
  emitModelDecl(interface);
  os << "};";

  // Emit the derived trait for the interface.
  os << "template <typename " << valueTemplate << ">\n";
  os << "struct " << interface.getName() << "Trait;\n";

  os << "\n} // end namespace detail\n";

  // Emit the main interface class declaration.
  os << llvm::formatv("class {0} : public ::mlir::{3}<{1}, detail::{2}> {\n"
                      "public:\n"
                      "  using ::mlir::{3}<{1}, detail::{2}>::{3};\n",
                      interfaceName, interfaceName, interfaceTraitsName,
                      interfaceBaseType);

  // Emit a utility wrapper trait class.
  os << llvm::formatv("  template <typename {1}>\n"
                      "  struct Trait : public detail::{0}Trait<{1}> {{};\n",
                      interfaceName, valueTemplate);

  // Insert the method declarations.
  bool isOpInterface = isa<OpInterface>(interface);
  for (auto &method : interface.getMethods()) {
    emitCPPType(method.getReturnType(), os << "  ");
    emitMethodNameAndArgs(method, os, valueType, /*addThisArg=*/false,
                          /*addConst=*/!isOpInterface);
    os << ";\n";
  }

  // Emit any extra declarations.
  if (Optional<StringRef> extraDecls = interface.getExtraClassDeclaration())
    os << *extraDecls << "\n";

  os << "};\n";

  os << "namespace detail {\n";
  emitTraitDecl(interface, interfaceName, interfaceTraitsName);
  os << "}// namespace detail\n";

  emitModelMethodsDef(interface);

  for (StringRef ns : llvm::reverse(namespaces))
    os << "} // namespace " << ns << "\n";
}

bool InterfaceGenerator::emitInterfaceDecls() {
  llvm::emitSourceFileHeader("Interface Declarations", os);

  for (const auto *def : defs)
    emitInterfaceDecl(Interface(def));
  return false;
}

//===----------------------------------------------------------------------===//
// GEN: Interface documentation
//===----------------------------------------------------------------------===//

static void emitInterfaceDoc(const llvm::Record &interfaceDef,
                             raw_ostream &os) {
  Interface interface(&interfaceDef);

  // Emit the interface name followed by the description.
  os << "## " << interface.getName() << " (`" << interfaceDef.getName()
     << "`)\n\n";
  if (auto description = interface.getDescription())
    mlir::tblgen::emitDescription(*description, os);

  // Emit the methods required by the interface.
  os << "\n### Methods:\n";
  for (const auto &method : interface.getMethods()) {
    // Emit the method name.
    os << "#### `" << method.getName() << "`\n\n```c++\n";

    // Emit the method signature.
    if (method.isStatic())
      os << "static ";
    emitCPPType(method.getReturnType(), os) << method.getName() << '(';
    llvm::interleaveComma(method.getArguments(), os,
                          [&](const InterfaceMethod::Argument &arg) {
                            emitCPPType(arg.type, os) << arg.name;
                          });
    os << ");\n```\n";

    // Emit the description.
    if (auto description = method.getDescription())
      mlir::tblgen::emitDescription(*description, os);

    // If the body is not provided, this method must be provided by the user.
    if (!method.getBody())
      os << "\nNOTE: This method *must* be implemented by the user.\n\n";
  }
}

bool InterfaceGenerator::emitInterfaceDocs() {
  os << "<!-- Autogenerated by mlir-tblgen; don't manually edit -->\n";
  os << "# " << interfaceBaseType << " definitions\n";

  for (const auto *def : defs)
    emitInterfaceDoc(*def, os);
  return false;
}

//===----------------------------------------------------------------------===//
// GEN: Interface registration hooks
//===----------------------------------------------------------------------===//

namespace {
template <typename GeneratorT>
struct InterfaceGenRegistration {
  InterfaceGenRegistration(StringRef genArg, StringRef genDesc)
      : genDeclArg(("gen-" + genArg + "-interface-decls").str()),
        genDefArg(("gen-" + genArg + "-interface-defs").str()),
        genDocArg(("gen-" + genArg + "-interface-docs").str()),
        genDeclDesc(("Generate " + genDesc + " interface declarations").str()),
        genDefDesc(("Generate " + genDesc + " interface definitions").str()),
        genDocDesc(("Generate " + genDesc + " interface documentation").str()),
        genDecls(genDeclArg, genDeclDesc,
                 [](const llvm::RecordKeeper &records, raw_ostream &os) {
                   return GeneratorT(records, os).emitInterfaceDecls();
                 }),
        genDefs(genDefArg, genDefDesc,
                [](const llvm::RecordKeeper &records, raw_ostream &os) {
                  return GeneratorT(records, os).emitInterfaceDefs();
                }),
        genDocs(genDocArg, genDocDesc,
                [](const llvm::RecordKeeper &records, raw_ostream &os) {
                  return GeneratorT(records, os).emitInterfaceDocs();
                }) {}

  std::string genDeclArg, genDefArg, genDocArg;
  std::string genDeclDesc, genDefDesc, genDocDesc;
  mlir::GenRegistration genDecls, genDefs, genDocs;
};
} // end anonymous namespace

static InterfaceGenRegistration<AttrInterfaceGenerator> attrGen("attr",
                                                                "attribute");
static InterfaceGenRegistration<OpInterfaceGenerator> opGen("op", "op");
static InterfaceGenRegistration<TypeInterfaceGenerator> typeGen("type", "type");