LLVMDialect.cpp

//===- LLVMDialect.cpp - LLVM IR Ops and Dialect registration -------------===//
//
// 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 the types and operation details for the LLVM IR dialect in
// MLIR, and the LLVM IR dialect.  It also registers the dialect.
//
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "LLVMInlining.h"
#include "TypeDetail.h"
#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
#include "mlir/Dialect/LLVMIR/LLVMInterfaces.h"
#include "mlir/Dialect/LLVMIR/LLVMTypes.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/BuiltinOps.h"
#include "mlir/IR/BuiltinTypes.h"
#include "mlir/IR/DialectImplementation.h"
#include "mlir/IR/MLIRContext.h"
#include "mlir/IR/Matchers.h"
#include "mlir/Interfaces/FunctionImplementation.h"

#include "llvm/ADT/SCCIterator.h"
#include "llvm/ADT/TypeSwitch.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/Bitcode/BitcodeWriter.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/SourceMgr.h"

#include <numeric>
#include <optional>

using namespace mlir;
using namespace mlir::LLVM;
using mlir::LLVM::cconv::getMaxEnumValForCConv;
using mlir::LLVM::linkage::getMaxEnumValForLinkage;

#include "mlir/Dialect/LLVMIR/LLVMOpsDialect.cpp.inc"

//===----------------------------------------------------------------------===//
// Property Helpers
//===----------------------------------------------------------------------===//

//===----------------------------------------------------------------------===//
// IntegerOverflowFlags

namespace mlir {
static Attribute convertToAttribute(MLIRContext *ctx,
                                    IntegerOverflowFlags flags) {
  return IntegerOverflowFlagsAttr::get(ctx, flags);
}

static LogicalResult
convertFromAttribute(IntegerOverflowFlags &flags, Attribute attr,
                     function_ref<InFlightDiagnostic()> emitError) {
  auto flagsAttr = dyn_cast<IntegerOverflowFlagsAttr>(attr);
  if (!flagsAttr) {
    return emitError() << "expected 'overflowFlags' attribute to be an "
                          "IntegerOverflowFlagsAttr, but got "
                       << attr;
  }
  flags = flagsAttr.getValue();
  return success();
}
} // namespace mlir

static ParseResult parseOverflowFlags(AsmParser &p,
                                      IntegerOverflowFlags &flags) {
  if (failed(p.parseOptionalKeyword("overflow"))) {
    flags = IntegerOverflowFlags::none;
    return success();
  }
  if (p.parseLess())
    return failure();
  do {
    StringRef kw;
    SMLoc loc = p.getCurrentLocation();
    if (p.parseKeyword(&kw))
      return failure();
    std::optional<IntegerOverflowFlags> flag =
        symbolizeIntegerOverflowFlags(kw);
    if (!flag)
      return p.emitError(loc,
                         "invalid overflow flag: expected nsw, nuw, or none");
    flags = flags | *flag;
  } while (succeeded(p.parseOptionalComma()));
  return p.parseGreater();
}

static void printOverflowFlags(AsmPrinter &p, Operation *op,
                               IntegerOverflowFlags flags) {
  if (flags == IntegerOverflowFlags::none)
    return;
  p << " overflow<";
  SmallVector<StringRef, 2> strs;
  if (bitEnumContainsAny(flags, IntegerOverflowFlags::nsw))
    strs.push_back("nsw");
  if (bitEnumContainsAny(flags, IntegerOverflowFlags::nuw))
    strs.push_back("nuw");
  llvm::interleaveComma(strs, p);
  p << ">";
}

//===----------------------------------------------------------------------===//
// Attribute Helpers
//===----------------------------------------------------------------------===//

static constexpr const char kElemTypeAttrName[] = "elem_type";

static auto processFMFAttr(ArrayRef<NamedAttribute> attrs) {
  SmallVector<NamedAttribute, 8> filteredAttrs(
      llvm::make_filter_range(attrs, [&](NamedAttribute attr) {
        if (attr.getName() == "fastmathFlags") {
          auto defAttr =
              FastmathFlagsAttr::get(attr.getValue().getContext(), {});
          return defAttr != attr.getValue();
        }
        return true;
      }));
  return filteredAttrs;
}

static ParseResult parseLLVMOpAttrs(OpAsmParser &parser,
                                    NamedAttrList &result) {
  return parser.parseOptionalAttrDict(result);
}

static void printLLVMOpAttrs(OpAsmPrinter &printer, Operation *op,
                             DictionaryAttr attrs) {
  auto filteredAttrs = processFMFAttr(attrs.getValue());
  if (auto iface = dyn_cast<IntegerOverflowFlagsInterface>(op)) {
    printer.printOptionalAttrDict(
        filteredAttrs, /*elidedAttrs=*/{iface.getOverflowFlagsAttrName()});
  } else {
    printer.printOptionalAttrDict(filteredAttrs);
  }
}

/// Verifies `symbol`'s use in `op` to ensure the symbol is a valid and
/// fully defined llvm.func.
static LogicalResult verifySymbolAttrUse(FlatSymbolRefAttr symbol,
                                         Operation *op,
                                         SymbolTableCollection &symbolTable) {
  StringRef name = symbol.getValue();
  auto func =
      symbolTable.lookupNearestSymbolFrom<LLVMFuncOp>(op, symbol.getAttr());
  if (!func)
    return op->emitOpError("'")
           << name << "' does not reference a valid LLVM function";
  if (func.isExternal())
    return op->emitOpError("'") << name << "' does not have a definition";
  return success();
}

/// Returns a boolean type that has the same shape as `type`. It supports both
/// fixed size vectors as well as scalable vectors.
static Type getI1SameShape(Type type) {
  Type i1Type = IntegerType::get(type.getContext(), 1);
  if (LLVM::isCompatibleVectorType(type))
    return LLVM::getVectorType(i1Type, LLVM::getVectorNumElements(type));
  return i1Type;
}

// Parses one of the keywords provided in the list `keywords` and returns the
// position of the parsed keyword in the list. If none of the keywords from the
// list is parsed, returns -1.
static int parseOptionalKeywordAlternative(OpAsmParser &parser,
                                           ArrayRef<StringRef> keywords) {
  for (const auto &en : llvm::enumerate(keywords)) {
    if (succeeded(parser.parseOptionalKeyword(en.value())))
      return en.index();
  }
  return -1;
}

namespace {
template <typename Ty>
struct EnumTraits {};

#define REGISTER_ENUM_TYPE(Ty)                                                 \
  template <>                                                                  \
  struct EnumTraits<Ty> {                                                      \
    static StringRef stringify(Ty value) { return stringify##Ty(value); }      \
    static unsigned getMaxEnumVal() { return getMaxEnumValFor##Ty(); }         \
  }

REGISTER_ENUM_TYPE(Linkage);
REGISTER_ENUM_TYPE(UnnamedAddr);
REGISTER_ENUM_TYPE(CConv);
REGISTER_ENUM_TYPE(Visibility);
} // namespace

/// Parse an enum from the keyword, or default to the provided default value.
/// The return type is the enum type by default, unless overridden with the
/// second template argument.
template <typename EnumTy, typename RetTy = EnumTy>
static RetTy parseOptionalLLVMKeyword(OpAsmParser &parser,
                                      OperationState &result,
                                      EnumTy defaultValue) {
  SmallVector<StringRef, 10> names;
  for (unsigned i = 0, e = EnumTraits<EnumTy>::getMaxEnumVal(); i <= e; ++i)
    names.push_back(EnumTraits<EnumTy>::stringify(static_cast<EnumTy>(i)));

  int index = parseOptionalKeywordAlternative(parser, names);
  if (index == -1)
    return static_cast<RetTy>(defaultValue);
  return static_cast<RetTy>(index);
}

//===----------------------------------------------------------------------===//
// Printing, parsing, folding and builder for LLVM::CmpOp.
//===----------------------------------------------------------------------===//

void ICmpOp::print(OpAsmPrinter &p) {
  p << " \"" << stringifyICmpPredicate(getPredicate()) << "\" " << getOperand(0)
    << ", " << getOperand(1);
  p.printOptionalAttrDict((*this)->getAttrs(), {"predicate"});
  p << " : " << getLhs().getType();
}

void FCmpOp::print(OpAsmPrinter &p) {
  p << " \"" << stringifyFCmpPredicate(getPredicate()) << "\" " << getOperand(0)
    << ", " << getOperand(1);
  p.printOptionalAttrDict(processFMFAttr((*this)->getAttrs()), {"predicate"});
  p << " : " << getLhs().getType();
}

// <operation> ::= `llvm.icmp` string-literal ssa-use `,` ssa-use
//                 attribute-dict? `:` type
// <operation> ::= `llvm.fcmp` string-literal ssa-use `,` ssa-use
//                 attribute-dict? `:` type
template <typename CmpPredicateType>
static ParseResult parseCmpOp(OpAsmParser &parser, OperationState &result) {
  StringAttr predicateAttr;
  OpAsmParser::UnresolvedOperand lhs, rhs;
  Type type;
  SMLoc predicateLoc, trailingTypeLoc;
  if (parser.getCurrentLocation(&predicateLoc) ||
      parser.parseAttribute(predicateAttr, "predicate", result.attributes) ||
      parser.parseOperand(lhs) || parser.parseComma() ||
      parser.parseOperand(rhs) ||
      parser.parseOptionalAttrDict(result.attributes) || parser.parseColon() ||
      parser.getCurrentLocation(&trailingTypeLoc) || parser.parseType(type) ||
      parser.resolveOperand(lhs, type, result.operands) ||
      parser.resolveOperand(rhs, type, result.operands))
    return failure();

  // Replace the string attribute `predicate` with an integer attribute.
  int64_t predicateValue = 0;
  if (std::is_same<CmpPredicateType, ICmpPredicate>()) {
    std::optional<ICmpPredicate> predicate =
        symbolizeICmpPredicate(predicateAttr.getValue());
    if (!predicate)
      return parser.emitError(predicateLoc)
             << "'" << predicateAttr.getValue()
             << "' is an incorrect value of the 'predicate' attribute";
    predicateValue = static_cast<int64_t>(*predicate);
  } else {
    std::optional<FCmpPredicate> predicate =
        symbolizeFCmpPredicate(predicateAttr.getValue());
    if (!predicate)
      return parser.emitError(predicateLoc)
             << "'" << predicateAttr.getValue()
             << "' is an incorrect value of the 'predicate' attribute";
    predicateValue = static_cast<int64_t>(*predicate);
  }

  result.attributes.set("predicate",
                        parser.getBuilder().getI64IntegerAttr(predicateValue));

  // The result type is either i1 or a vector type <? x i1> if the inputs are
  // vectors.
  if (!isCompatibleType(type))
    return parser.emitError(trailingTypeLoc,
                            "expected LLVM dialect-compatible type");
  result.addTypes(getI1SameShape(type));
  return success();
}

ParseResult ICmpOp::parse(OpAsmParser &parser, OperationState &result) {
  return parseCmpOp<ICmpPredicate>(parser, result);
}

ParseResult FCmpOp::parse(OpAsmParser &parser, OperationState &result) {
  return parseCmpOp<FCmpPredicate>(parser, result);
}

/// Returns a scalar or vector boolean attribute of the given type.
static Attribute getBoolAttribute(Type type, MLIRContext *ctx, bool value) {
  auto boolAttr = BoolAttr::get(ctx, value);
  ShapedType shapedType = dyn_cast<ShapedType>(type);
  if (!shapedType)
    return boolAttr;
  return DenseElementsAttr::get(shapedType, boolAttr);
}

OpFoldResult ICmpOp::fold(FoldAdaptor adaptor) {
  if (getPredicate() != ICmpPredicate::eq &&
      getPredicate() != ICmpPredicate::ne)
    return {};

  // cmpi(eq/ne, x, x) -> true/false
  if (getLhs() == getRhs())
    return getBoolAttribute(getType(), getContext(),
                            getPredicate() == ICmpPredicate::eq);

  // cmpi(eq/ne, alloca, null) -> false/true
  if (getLhs().getDefiningOp<AllocaOp>() && getRhs().getDefiningOp<ZeroOp>())
    return getBoolAttribute(getType(), getContext(),
                            getPredicate() == ICmpPredicate::ne);

  // cmpi(eq/ne, null, alloca) -> cmpi(eq/ne, alloca, null)
  if (getLhs().getDefiningOp<ZeroOp>() && getRhs().getDefiningOp<AllocaOp>()) {
    Value lhs = getLhs();
    Value rhs = getRhs();
    getLhsMutable().assign(rhs);
    getRhsMutable().assign(lhs);
    return getResult();
  }

  return {};
}

//===----------------------------------------------------------------------===//
// Printing, parsing and verification for LLVM::AllocaOp.
//===----------------------------------------------------------------------===//

void AllocaOp::print(OpAsmPrinter &p) {
  auto funcTy =
      FunctionType::get(getContext(), {getArraySize().getType()}, {getType()});

  if (getInalloca())
    p << " inalloca";

  p << ' ' << getArraySize() << " x " << getElemType();
  if (getAlignment() && *getAlignment() != 0)
    p.printOptionalAttrDict((*this)->getAttrs(),
                            {kElemTypeAttrName, getInallocaAttrName()});
  else
    p.printOptionalAttrDict(
        (*this)->getAttrs(),
        {getAlignmentAttrName(), kElemTypeAttrName, getInallocaAttrName()});
  p << " : " << funcTy;
}

// <operation> ::= `llvm.alloca` `inalloca`? ssa-use `x` type
//                  attribute-dict? `:` type `,` type
ParseResult AllocaOp::parse(OpAsmParser &parser, OperationState &result) {
  OpAsmParser::UnresolvedOperand arraySize;
  Type type, elemType;
  SMLoc trailingTypeLoc;

  if (succeeded(parser.parseOptionalKeyword("inalloca")))
    result.addAttribute(getInallocaAttrName(result.name),
                        UnitAttr::get(parser.getContext()));

  if (parser.parseOperand(arraySize) || parser.parseKeyword("x") ||
      parser.parseType(elemType) ||
      parser.parseOptionalAttrDict(result.attributes) || parser.parseColon() ||
      parser.getCurrentLocation(&trailingTypeLoc) || parser.parseType(type))
    return failure();

  std::optional<NamedAttribute> alignmentAttr =
      result.attributes.getNamed("alignment");
  if (alignmentAttr.has_value()) {
    auto alignmentInt = llvm::dyn_cast<IntegerAttr>(alignmentAttr->getValue());
    if (!alignmentInt)
      return parser.emitError(parser.getNameLoc(),
                              "expected integer alignment");
    if (alignmentInt.getValue().isZero())
      result.attributes.erase("alignment");
  }

  // Extract the result type from the trailing function type.
  auto funcType = llvm::dyn_cast<FunctionType>(type);
  if (!funcType || funcType.getNumInputs() != 1 ||
      funcType.getNumResults() != 1)
    return parser.emitError(
        trailingTypeLoc,
        "expected trailing function type with one argument and one result");

  if (parser.resolveOperand(arraySize, funcType.getInput(0), result.operands))
    return failure();

  Type resultType = funcType.getResult(0);
  if (auto ptrResultType = llvm::dyn_cast<LLVMPointerType>(resultType))
    result.addAttribute(kElemTypeAttrName, TypeAttr::get(elemType));

  result.addTypes({funcType.getResult(0)});
  return success();
}

LogicalResult AllocaOp::verify() {
  // Only certain target extension types can be used in 'alloca'.
  if (auto targetExtType = dyn_cast<LLVMTargetExtType>(getElemType());
      targetExtType && !targetExtType.supportsMemOps())
    return emitOpError()
           << "this target extension type cannot be used in alloca";

  return success();
}

Type AllocaOp::getResultPtrElementType() { return getElemType(); }

//===----------------------------------------------------------------------===//
// LLVM::BrOp
//===----------------------------------------------------------------------===//

SuccessorOperands BrOp::getSuccessorOperands(unsigned index) {
  assert(index == 0 && "invalid successor index");
  return SuccessorOperands(getDestOperandsMutable());
}

//===----------------------------------------------------------------------===//
// LLVM::CondBrOp
//===----------------------------------------------------------------------===//

SuccessorOperands CondBrOp::getSuccessorOperands(unsigned index) {
  assert(index < getNumSuccessors() && "invalid successor index");
  return SuccessorOperands(index == 0 ? getTrueDestOperandsMutable()
                                      : getFalseDestOperandsMutable());
}

void CondBrOp::build(OpBuilder &builder, OperationState &result,
                     Value condition, Block *trueDest, ValueRange trueOperands,
                     Block *falseDest, ValueRange falseOperands,
                     std::optional<std::pair<uint32_t, uint32_t>> weights) {
  DenseI32ArrayAttr weightsAttr;
  if (weights)
    weightsAttr =
        builder.getDenseI32ArrayAttr({static_cast<int32_t>(weights->first),
                                      static_cast<int32_t>(weights->second)});

  build(builder, result, condition, trueOperands, falseOperands, weightsAttr,
        /*loop_annotation=*/{}, trueDest, falseDest);
}

//===----------------------------------------------------------------------===//
// LLVM::SwitchOp
//===----------------------------------------------------------------------===//

void SwitchOp::build(OpBuilder &builder, OperationState &result, Value value,
                     Block *defaultDestination, ValueRange defaultOperands,
                     DenseIntElementsAttr caseValues,
                     BlockRange caseDestinations,
                     ArrayRef<ValueRange> caseOperands,
                     ArrayRef<int32_t> branchWeights) {
  DenseI32ArrayAttr weightsAttr;
  if (!branchWeights.empty())
    weightsAttr = builder.getDenseI32ArrayAttr(branchWeights);

  build(builder, result, value, defaultOperands, caseOperands, caseValues,
        weightsAttr, defaultDestination, caseDestinations);
}

void SwitchOp::build(OpBuilder &builder, OperationState &result, Value value,
                     Block *defaultDestination, ValueRange defaultOperands,
                     ArrayRef<APInt> caseValues, BlockRange caseDestinations,
                     ArrayRef<ValueRange> caseOperands,
                     ArrayRef<int32_t> branchWeights) {
  DenseIntElementsAttr caseValuesAttr;
  if (!caseValues.empty()) {
    ShapedType caseValueType = VectorType::get(
        static_cast<int64_t>(caseValues.size()), value.getType());
    caseValuesAttr = DenseIntElementsAttr::get(caseValueType, caseValues);
  }

  build(builder, result, value, defaultDestination, defaultOperands,
        caseValuesAttr, caseDestinations, caseOperands, branchWeights);
}

void SwitchOp::build(OpBuilder &builder, OperationState &result, Value value,
                     Block *defaultDestination, ValueRange defaultOperands,
                     ArrayRef<int32_t> caseValues, BlockRange caseDestinations,
                     ArrayRef<ValueRange> caseOperands,
                     ArrayRef<int32_t> branchWeights) {
  DenseIntElementsAttr caseValuesAttr;
  if (!caseValues.empty()) {
    ShapedType caseValueType = VectorType::get(
        static_cast<int64_t>(caseValues.size()), value.getType());
    caseValuesAttr = DenseIntElementsAttr::get(caseValueType, caseValues);
  }

  build(builder, result, value, defaultDestination, defaultOperands,
        caseValuesAttr, caseDestinations, caseOperands, branchWeights);
}

/// <cases> ::= `[` (case (`,` case )* )? `]`
/// <case>  ::= integer `:` bb-id (`(` ssa-use-and-type-list `)`)?
static ParseResult parseSwitchOpCases(
    OpAsmParser &parser, Type flagType, DenseIntElementsAttr &caseValues,
    SmallVectorImpl<Block *> &caseDestinations,
    SmallVectorImpl<SmallVector<OpAsmParser::UnresolvedOperand>> &caseOperands,
    SmallVectorImpl<SmallVector<Type>> &caseOperandTypes) {
  if (failed(parser.parseLSquare()))
    return failure();
  if (succeeded(parser.parseOptionalRSquare()))
    return success();
  SmallVector<APInt> values;
  unsigned bitWidth = flagType.getIntOrFloatBitWidth();
  auto parseCase = [&]() {
    int64_t value = 0;
    if (failed(parser.parseInteger(value)))
      return failure();
    values.push_back(APInt(bitWidth, value));

    Block *destination;
    SmallVector<OpAsmParser::UnresolvedOperand> operands;
    SmallVector<Type> operandTypes;
    if (parser.parseColon() || parser.parseSuccessor(destination))
      return failure();
    if (!parser.parseOptionalLParen()) {
      if (parser.parseOperandList(operands, OpAsmParser::Delimiter::None,
                                  /*allowResultNumber=*/false) ||
          parser.parseColonTypeList(operandTypes) || parser.parseRParen())
        return failure();
    }
    caseDestinations.push_back(destination);
    caseOperands.emplace_back(operands);
    caseOperandTypes.emplace_back(operandTypes);
    return success();
  };
  if (failed(parser.parseCommaSeparatedList(parseCase)))
    return failure();

  ShapedType caseValueType =
      VectorType::get(static_cast<int64_t>(values.size()), flagType);
  caseValues = DenseIntElementsAttr::get(caseValueType, values);
  return parser.parseRSquare();
}

static void printSwitchOpCases(OpAsmPrinter &p, SwitchOp op, Type flagType,
                               DenseIntElementsAttr caseValues,
                               SuccessorRange caseDestinations,
                               OperandRangeRange caseOperands,
                               const TypeRangeRange &caseOperandTypes) {
  p << '[';
  p.printNewline();
  if (!caseValues) {
    p << ']';
    return;
  }

  size_t index = 0;
  llvm::interleave(
      llvm::zip(caseValues, caseDestinations),
      [&](auto i) {
        p << "  ";
        p << std::get<0>(i).getLimitedValue();
        p << ": ";
        p.printSuccessorAndUseList(std::get<1>(i), caseOperands[index++]);
      },
      [&] {
        p << ',';
        p.printNewline();
      });
  p.printNewline();
  p << ']';
}

LogicalResult SwitchOp::verify() {
  if ((!getCaseValues() && !getCaseDestinations().empty()) ||
      (getCaseValues() &&
       getCaseValues()->size() !=
           static_cast<int64_t>(getCaseDestinations().size())))
    return emitOpError("expects number of case values to match number of "
                       "case destinations");
  if (getBranchWeights() && getBranchWeights()->size() != getNumSuccessors())
    return emitError("expects number of branch weights to match number of "
                     "successors: ")
           << getBranchWeights()->size() << " vs " << getNumSuccessors();
  if (getCaseValues() &&
      getValue().getType() != getCaseValues()->getElementType())
    return emitError("expects case value type to match condition value type");
  return success();
}

SuccessorOperands SwitchOp::getSuccessorOperands(unsigned index) {
  assert(index < getNumSuccessors() && "invalid successor index");
  return SuccessorOperands(index == 0 ? getDefaultOperandsMutable()
                                      : getCaseOperandsMutable(index - 1));
}

//===----------------------------------------------------------------------===//
// Code for LLVM::GEPOp.
//===----------------------------------------------------------------------===//

constexpr int32_t GEPOp::kDynamicIndex;

GEPIndicesAdaptor<ValueRange> GEPOp::getIndices() {
  return GEPIndicesAdaptor<ValueRange>(getRawConstantIndicesAttr(),
                                       getDynamicIndices());
}

/// Returns the elemental type of any LLVM-compatible vector type or self.
static Type extractVectorElementType(Type type) {
  if (auto vectorType = llvm::dyn_cast<VectorType>(type))
    return vectorType.getElementType();
  if (auto scalableVectorType = llvm::dyn_cast<LLVMScalableVectorType>(type))
    return scalableVectorType.getElementType();
  if (auto fixedVectorType = llvm::dyn_cast<LLVMFixedVectorType>(type))
    return fixedVectorType.getElementType();
  return type;
}

/// Destructures the 'indices' parameter into 'rawConstantIndices' and
/// 'dynamicIndices', encoding the former in the process. In the process,
/// dynamic indices which are used to index into a structure type are converted
/// to constant indices when possible. To do this, the GEPs element type should
/// be passed as first parameter.
static void destructureIndices(Type currType, ArrayRef<GEPArg> indices,
                               SmallVectorImpl<int32_t> &rawConstantIndices,
                               SmallVectorImpl<Value> &dynamicIndices) {
  for (const GEPArg &iter : indices) {
    // If the thing we are currently indexing into is a struct we must turn
    // any integer constants into constant indices. If this is not possible
    // we don't do anything here. The verifier will catch it and emit a proper
    // error. All other canonicalization is done in the fold method.
    bool requiresConst = !rawConstantIndices.empty() &&
                         isa_and_nonnull<LLVMStructType>(currType);
    if (Value val = llvm::dyn_cast_if_present<Value>(iter)) {
      APInt intC;
      if (requiresConst && matchPattern(val, m_ConstantInt(&intC)) &&
          intC.isSignedIntN(kGEPConstantBitWidth)) {
        rawConstantIndices.push_back(intC.getSExtValue());
      } else {
        rawConstantIndices.push_back(GEPOp::kDynamicIndex);
        dynamicIndices.push_back(val);
      }
    } else {
      rawConstantIndices.push_back(iter.get<GEPConstantIndex>());
    }

    // Skip for very first iteration of this loop. First index does not index
    // within the aggregates, but is just a pointer offset.
    if (rawConstantIndices.size() == 1 || !currType)
      continue;

    currType =
        TypeSwitch<Type, Type>(currType)
            .Case<VectorType, LLVMScalableVectorType, LLVMFixedVectorType,
                  LLVMArrayType>([](auto containerType) {
              return containerType.getElementType();
            })
            .Case([&](LLVMStructType structType) -> Type {
              int64_t memberIndex = rawConstantIndices.back();
              if (memberIndex >= 0 && static_cast<size_t>(memberIndex) <
                                          structType.getBody().size())
                return structType.getBody()[memberIndex];
              return nullptr;
            })
            .Default(Type(nullptr));
  }
}

void GEPOp::build(OpBuilder &builder, OperationState &result, Type resultType,
                  Type elementType, Value basePtr, ArrayRef<GEPArg> indices,
                  bool inbounds, ArrayRef<NamedAttribute> attributes) {
  SmallVector<int32_t> rawConstantIndices;
  SmallVector<Value> dynamicIndices;
  destructureIndices(elementType, indices, rawConstantIndices, dynamicIndices);

  result.addTypes(resultType);
  result.addAttributes(attributes);
  result.addAttribute(getRawConstantIndicesAttrName(result.name),
                      builder.getDenseI32ArrayAttr(rawConstantIndices));
  if (inbounds) {
    result.addAttribute(getInboundsAttrName(result.name),
                        builder.getUnitAttr());
  }
  result.addAttribute(kElemTypeAttrName, TypeAttr::get(elementType));
  result.addOperands(basePtr);
  result.addOperands(dynamicIndices);
}

void GEPOp::build(OpBuilder &builder, OperationState &result, Type resultType,
                  Type elementType, Value basePtr, ValueRange indices,
                  bool inbounds, ArrayRef<NamedAttribute> attributes) {
  build(builder, result, resultType, elementType, basePtr,
        SmallVector<GEPArg>(indices), inbounds, attributes);
}

static ParseResult
parseGEPIndices(OpAsmParser &parser,
                SmallVectorImpl<OpAsmParser::UnresolvedOperand> &indices,
                DenseI32ArrayAttr &rawConstantIndices) {
  SmallVector<int32_t> constantIndices;

  auto idxParser = [&]() -> ParseResult {
    int32_t constantIndex;
    OptionalParseResult parsedInteger =
        parser.parseOptionalInteger(constantIndex);
    if (parsedInteger.has_value()) {
      if (failed(parsedInteger.value()))
        return failure();
      constantIndices.push_back(constantIndex);
      return success();
    }

    constantIndices.push_back(LLVM::GEPOp::kDynamicIndex);
    return parser.parseOperand(indices.emplace_back());
  };
  if (parser.parseCommaSeparatedList(idxParser))
    return failure();

  rawConstantIndices =
      DenseI32ArrayAttr::get(parser.getContext(), constantIndices);
  return success();
}

static void printGEPIndices(OpAsmPrinter &printer, LLVM::GEPOp gepOp,
                            OperandRange indices,
                            DenseI32ArrayAttr rawConstantIndices) {
  llvm::interleaveComma(
      GEPIndicesAdaptor<OperandRange>(rawConstantIndices, indices), printer,
      [&](PointerUnion<IntegerAttr, Value> cst) {
        if (Value val = llvm::dyn_cast_if_present<Value>(cst))
          printer.printOperand(val);
        else
          printer << cst.get<IntegerAttr>().getInt();
      });
}

/// For the given `indices`, check if they comply with `baseGEPType`,
/// especially check against LLVMStructTypes nested within.
static LogicalResult
verifyStructIndices(Type baseGEPType, unsigned indexPos,
                    GEPIndicesAdaptor<ValueRange> indices,
                    function_ref<InFlightDiagnostic()> emitOpError) {
  if (indexPos >= indices.size())
    // Stop searching
    return success();

  return TypeSwitch<Type, LogicalResult>(baseGEPType)
      .Case<LLVMStructType>([&](LLVMStructType structType) -> LogicalResult {
        if (!indices[indexPos].is<IntegerAttr>())
          return emitOpError() << "expected index " << indexPos
                               << " indexing a struct to be constant";

        int32_t gepIndex = indices[indexPos].get<IntegerAttr>().getInt();
        ArrayRef<Type> elementTypes = structType.getBody();
        if (gepIndex < 0 ||
            static_cast<size_t>(gepIndex) >= elementTypes.size())
          return emitOpError() << "index " << indexPos
                               << " indexing a struct is out of bounds";

        // Instead of recursively going into every children types, we only
        // dive into the one indexed by gepIndex.
        return verifyStructIndices(elementTypes[gepIndex], indexPos + 1,
                                   indices, emitOpError);
      })
      .Case<VectorType, LLVMScalableVectorType, LLVMFixedVectorType,
            LLVMArrayType>([&](auto containerType) -> LogicalResult {
        return verifyStructIndices(containerType.getElementType(), indexPos + 1,
                                   indices, emitOpError);
      })
      .Default([&](auto otherType) -> LogicalResult {
        return emitOpError()
               << "type " << otherType << " cannot be indexed (index #"
               << indexPos << ")";
      });
}

/// Driver function around `verifyStructIndices`.
static LogicalResult
verifyStructIndices(Type baseGEPType, GEPIndicesAdaptor<ValueRange> indices,
                    function_ref<InFlightDiagnostic()> emitOpError) {
  return verifyStructIndices(baseGEPType, /*indexPos=*/1, indices, emitOpError);
}

LogicalResult LLVM::GEPOp::verify() {
  if (static_cast<size_t>(
          llvm::count(getRawConstantIndices(), kDynamicIndex)) !=
      getDynamicIndices().size())
    return emitOpError("expected as many dynamic indices as specified in '")
           << getRawConstantIndicesAttrName().getValue() << "'";

  return verifyStructIndices(getElemType(), getIndices(),
                             [&] { return emitOpError(); });
}

Type GEPOp::getResultPtrElementType() {
  // Set the initial type currently being used for indexing. This will be
  // updated as the indices get walked over.
  Type selectedType = getElemType();

  // Follow the indexed elements in the gep.
  auto indices = getIndices();
  for (GEPIndicesAdaptor<ValueRange>::value_type index :
       llvm::drop_begin(indices)) {
    // GEPs can only index into aggregates which can be structs or arrays.

    // The resulting type if indexing into an array type is always the element
    // type, regardless of index.
    if (auto arrayType = dyn_cast<LLVMArrayType>(selectedType)) {
      selectedType = arrayType.getElementType();
      continue;
    }

    // The GEP verifier ensures that any index into structs are static and
    // that they refer to a field within the struct.
    selectedType = cast<DestructurableTypeInterface>(selectedType)
                       .getTypeAtIndex(cast<IntegerAttr>(index));
  }

  // When there are no more indices, the type currently being used for indexing
  // is the type of the value pointed at by the returned indexed pointer.
  return selectedType;
}

//===----------------------------------------------------------------------===//
// LoadOp
//===----------------------------------------------------------------------===//

void LoadOp::getEffects(
    SmallVectorImpl<SideEffects::EffectInstance<MemoryEffects::Effect>>
        &effects) {
  effects.emplace_back(MemoryEffects::Read::get(), getAddr());
  // Volatile operations can have target-specific read-write effects on
  // memory besides the one referred to by the pointer operand.
  // Similarly, atomic operations that are monotonic or stricter cause
  // synchronization that from a language point-of-view, are arbitrary
  // read-writes into memory.
  if (getVolatile_() || (getOrdering() != AtomicOrdering::not_atomic &&
                         getOrdering() != AtomicOrdering::unordered)) {
    effects.emplace_back(MemoryEffects::Write::get());
    effects.emplace_back(MemoryEffects::Read::get());
  }
}

/// Returns true if the given type is supported by atomic operations. All
/// integer, float, and pointer types with a power-of-two bitsize and a minimal
/// size of 8 bits are supported.
static bool isTypeCompatibleWithAtomicOp(Type type,
                                         const DataLayout &dataLayout) {
  if (!isa<IntegerType, LLVMPointerType>(type))
    if (!isCompatibleFloatingPointType(type))
      return false;

  llvm::TypeSize bitWidth = dataLayout.getTypeSizeInBits(type);
  if (bitWidth.isScalable())
    return false;
  // Needs to be at least 8 bits and a power of two.
  return bitWidth >= 8 && (bitWidth & (bitWidth - 1)) == 0;
}

/// Verifies the attributes and the type of atomic memory access operations.
template <typename OpTy>
LogicalResult verifyAtomicMemOp(OpTy memOp, Type valueType,
                                ArrayRef<AtomicOrdering> unsupportedOrderings) {
  if (memOp.getOrdering() != AtomicOrdering::not_atomic) {
    DataLayout dataLayout = DataLayout::closest(memOp);
    if (!isTypeCompatibleWithAtomicOp(valueType, dataLayout))
      return memOp.emitOpError("unsupported type ")
             << valueType << " for atomic access";
    if (llvm::is_contained(unsupportedOrderings, memOp.getOrdering()))
      return memOp.emitOpError("unsupported ordering '")
             << stringifyAtomicOrdering(memOp.getOrdering()) << "'";
    if (!memOp.getAlignment())
      return memOp.emitOpError("expected alignment for atomic access");
    return success();
  }
  if (memOp.getSyncscope())
    return memOp.emitOpError(
        "expected syncscope to be null for non-atomic access");
  return success();
}

LogicalResult LoadOp::verify() {
  Type valueType = getResult().getType();
  return verifyAtomicMemOp(*this, valueType,
                           {AtomicOrdering::release, AtomicOrdering::acq_rel});
}

void LoadOp::build(OpBuilder &builder, OperationState &state, Type type,
                   Value addr, unsigned alignment, bool isVolatile,
                   bool isNonTemporal, bool isInvariant,
                   AtomicOrdering ordering, StringRef syncscope) {
  build(builder, state, type, addr,
        alignment ? builder.getI64IntegerAttr(alignment) : nullptr, isVolatile,
        isNonTemporal, isInvariant, ordering,
        syncscope.empty() ? nullptr : builder.getStringAttr(syncscope),
        /*access_groups=*/nullptr,
        /*alias_scopes=*/nullptr, /*noalias_scopes=*/nullptr,
        /*tbaa=*/nullptr);
}

//===----------------------------------------------------------------------===//
// StoreOp
//===----------------------------------------------------------------------===//

void StoreOp::getEffects(
    SmallVectorImpl<SideEffects::EffectInstance<MemoryEffects::Effect>>
        &effects) {
  effects.emplace_back(MemoryEffects::Write::get(), getAddr());
  // Volatile operations can have target-specific read-write effects on
  // memory besides the one referred to by the pointer operand.
  // Similarly, atomic operations that are monotonic or stricter cause
  // synchronization that from a language point-of-view, are arbitrary
  // read-writes into memory.
  if (getVolatile_() || (getOrdering() != AtomicOrdering::not_atomic &&
                         getOrdering() != AtomicOrdering::unordered)) {
    effects.emplace_back(MemoryEffects::Write::get());
    effects.emplace_back(MemoryEffects::Read::get());
  }
}

LogicalResult StoreOp::verify() {
  Type valueType = getValue().getType();
  return verifyAtomicMemOp(*this, valueType,
                           {AtomicOrdering::acquire, AtomicOrdering::acq_rel});
}

void StoreOp::build(OpBuilder &builder, OperationState &state, Value value,
                    Value addr, unsigned alignment, bool isVolatile,
                    bool isNonTemporal, AtomicOrdering ordering,
                    StringRef syncscope) {
  build(builder, state, value, addr,
        alignment ? builder.getI64IntegerAttr(alignment) : nullptr, isVolatile,
        isNonTemporal, ordering,
        syncscope.empty() ? nullptr : builder.getStringAttr(syncscope),
        /*access_groups=*/nullptr,
        /*alias_scopes=*/nullptr, /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);
}

//===----------------------------------------------------------------------===//
// CallOp
//===----------------------------------------------------------------------===//

/// Gets the MLIR Op-like result types of a LLVMFunctionType.
static SmallVector<Type, 1> getCallOpResultTypes(LLVMFunctionType calleeType) {
  SmallVector<Type, 1> results;
  Type resultType = calleeType.getReturnType();
  if (!isa<LLVM::LLVMVoidType>(resultType))
    results.push_back(resultType);
  return results;
}

/// Constructs a LLVMFunctionType from MLIR `results` and `args`.
static LLVMFunctionType getLLVMFuncType(MLIRContext *context, TypeRange results,
                                        ValueRange args) {
  Type resultType;
  if (results.empty())
    resultType = LLVMVoidType::get(context);
  else
    resultType = results.front();
  return LLVMFunctionType::get(resultType, llvm::to_vector(args.getTypes()),
                               /*isVarArg=*/false);
}

void CallOp::build(OpBuilder &builder, OperationState &state, TypeRange results,
                   StringRef callee, ValueRange args) {
  build(builder, state, results, builder.getStringAttr(callee), args);
}

void CallOp::build(OpBuilder &builder, OperationState &state, TypeRange results,
                   StringAttr callee, ValueRange args) {
  build(builder, state, results, SymbolRefAttr::get(callee), args);
}

void CallOp::build(OpBuilder &builder, OperationState &state, TypeRange results,
                   FlatSymbolRefAttr callee, ValueRange args) {
  assert(callee && "expected non-null callee in direct call builder");
  build(builder, state, results,
        TypeAttr::get(getLLVMFuncType(builder.getContext(), results, args)),
        callee, args, /*fastmathFlags=*/nullptr, /*branch_weights=*/nullptr,
        /*CConv=*/nullptr,
        /*access_groups=*/nullptr, /*alias_scopes=*/nullptr,
        /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);
}

void CallOp::build(OpBuilder &builder, OperationState &state,
                   LLVMFunctionType calleeType, StringRef callee,
                   ValueRange args) {
  build(builder, state, calleeType, builder.getStringAttr(callee), args);
}

void CallOp::build(OpBuilder &builder, OperationState &state,
                   LLVMFunctionType calleeType, StringAttr callee,
                   ValueRange args) {
  build(builder, state, calleeType, SymbolRefAttr::get(callee), args);
}

void CallOp::build(OpBuilder &builder, OperationState &state,
                   LLVMFunctionType calleeType, FlatSymbolRefAttr callee,
                   ValueRange args) {
  build(builder, state, getCallOpResultTypes(calleeType),
        TypeAttr::get(calleeType), callee, args, /*fastmathFlags=*/nullptr,
        /*branch_weights=*/nullptr, /*CConv=*/nullptr,
        /*access_groups=*/nullptr,
        /*alias_scopes=*/nullptr, /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);
}

void CallOp::build(OpBuilder &builder, OperationState &state,
                   LLVMFunctionType calleeType, ValueRange args) {
  build(builder, state, getCallOpResultTypes(calleeType),
        TypeAttr::get(calleeType), /*callee=*/nullptr, args,
        /*fastmathFlags=*/nullptr, /*branch_weights=*/nullptr,
        /*CConv=*/nullptr,
        /*access_groups=*/nullptr, /*alias_scopes=*/nullptr,
        /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);
}

void CallOp::build(OpBuilder &builder, OperationState &state, LLVMFuncOp func,
                   ValueRange args) {
  auto calleeType = func.getFunctionType();
  build(builder, state, getCallOpResultTypes(calleeType),
        TypeAttr::get(calleeType), SymbolRefAttr::get(func), args,
        /*fastmathFlags=*/nullptr, /*branch_weights=*/nullptr,
        /*CConv=*/nullptr,
        /*access_groups=*/nullptr, /*alias_scopes=*/nullptr,
        /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);
}

CallInterfaceCallable CallOp::getCallableForCallee() {
  // Direct call.
  if (FlatSymbolRefAttr calleeAttr = getCalleeAttr())
    return calleeAttr;
  // Indirect call, callee Value is the first operand.
  return getOperand(0);
}

void CallOp::setCalleeFromCallable(CallInterfaceCallable callee) {
  // Direct call.
  if (FlatSymbolRefAttr calleeAttr = getCalleeAttr()) {
    auto symRef = callee.get<SymbolRefAttr>();
    return setCalleeAttr(cast<FlatSymbolRefAttr>(symRef));
  }
  // Indirect call, callee Value is the first operand.
  return setOperand(0, callee.get<Value>());
}

Operation::operand_range CallOp::getArgOperands() {
  return getOperands().drop_front(getCallee().has_value() ? 0 : 1);
}

MutableOperandRange CallOp::getArgOperandsMutable() {
  return MutableOperandRange(*this, getCallee().has_value() ? 0 : 1,
                             getCalleeOperands().size());
}

/// Verify that an inlinable callsite of a debug-info-bearing function in a
/// debug-info-bearing function has a debug location attached to it. This
/// mirrors an LLVM IR verifier.
static LogicalResult verifyCallOpDebugInfo(CallOp callOp, LLVMFuncOp callee) {
  if (callee.isExternal())
    return success();
  auto parentFunc = callOp->getParentOfType<FunctionOpInterface>();
  if (!parentFunc)
    return success();

  auto hasSubprogram = [](Operation *op) {
    return op->getLoc()
               ->findInstanceOf<FusedLocWith<LLVM::DISubprogramAttr>>() !=
           nullptr;
  };
  if (!hasSubprogram(parentFunc) || !hasSubprogram(callee))
    return success();
  bool containsLoc = !isa<UnknownLoc>(callOp->getLoc());
  if (!containsLoc)
    return callOp.emitError()
           << "inlinable function call in a function with a DISubprogram "
              "location must have a debug location";
  return success();
}

LogicalResult CallOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
  if (getNumResults() > 1)
    return emitOpError("must have 0 or 1 result");

  // Type for the callee, we'll get it differently depending if it is a direct
  // or indirect call.
  Type fnType;

  bool isIndirect = false;

  // If this is an indirect call, the callee attribute is missing.
  FlatSymbolRefAttr calleeName = getCalleeAttr();
  if (!calleeName) {
    isIndirect = true;
    if (!getNumOperands())
      return emitOpError(
          "must have either a `callee` attribute or at least an operand");
    auto ptrType = llvm::dyn_cast<LLVMPointerType>(getOperand(0).getType());
    if (!ptrType)
      return emitOpError("indirect call expects a pointer as callee: ")
             << getOperand(0).getType();

    return success();
  } else {
    Operation *callee =
        symbolTable.lookupNearestSymbolFrom(*this, calleeName.getAttr());
    if (!callee)
      return emitOpError()
             << "'" << calleeName.getValue()
             << "' does not reference a symbol in the current scope";
    auto fn = dyn_cast<LLVMFuncOp>(callee);
    if (!fn)
      return emitOpError() << "'" << calleeName.getValue()
                           << "' does not reference a valid LLVM function";

    if (failed(verifyCallOpDebugInfo(*this, fn)))
      return failure();
    fnType = fn.getFunctionType();
  }

  LLVMFunctionType funcType = llvm::dyn_cast<LLVMFunctionType>(fnType);
  if (!funcType)
    return emitOpError("callee does not have a functional type: ") << fnType;

  if (funcType.isVarArg() && !getCalleeType())
    return emitOpError() << "missing callee type attribute for vararg call";

  // Verify that the operand and result types match the callee.

  if (!funcType.isVarArg() &&
      funcType.getNumParams() != (getNumOperands() - isIndirect))
    return emitOpError() << "incorrect number of operands ("
                         << (getNumOperands() - isIndirect)
                         << ") for callee (expecting: "
                         << funcType.getNumParams() << ")";

  if (funcType.getNumParams() > (getNumOperands() - isIndirect))
    return emitOpError() << "incorrect number of operands ("
                         << (getNumOperands() - isIndirect)
                         << ") for varargs callee (expecting at least: "
                         << funcType.getNumParams() << ")";

  for (unsigned i = 0, e = funcType.getNumParams(); i != e; ++i)
    if (getOperand(i + isIndirect).getType() != funcType.getParamType(i))
      return emitOpError() << "operand type mismatch for operand " << i << ": "
                           << getOperand(i + isIndirect).getType()
                           << " != " << funcType.getParamType(i);

  if (getNumResults() == 0 &&
      !llvm::isa<LLVM::LLVMVoidType>(funcType.getReturnType()))
    return emitOpError() << "expected function call to produce a value";

  if (getNumResults() != 0 &&
      llvm::isa<LLVM::LLVMVoidType>(funcType.getReturnType()))
    return emitOpError()
           << "calling function with void result must not produce values";

  if (getNumResults() > 1)
    return emitOpError()
           << "expected LLVM function call to produce 0 or 1 result";

  if (getNumResults() && getResult().getType() != funcType.getReturnType())
    return emitOpError() << "result type mismatch: " << getResult().getType()
                         << " != " << funcType.getReturnType();

  return success();
}

void CallOp::print(OpAsmPrinter &p) {
  auto callee = getCallee();
  bool isDirect = callee.has_value();

  LLVMFunctionType calleeType;
  bool isVarArg = false;

  if (std::optional<LLVMFunctionType> optionalCalleeType = getCalleeType()) {
    calleeType = *optionalCalleeType;
    isVarArg = calleeType.isVarArg();
  }

  p << ' ';

  // Print calling convention.
  if (getCConv() != LLVM::CConv::C)
    p << stringifyCConv(getCConv()) << ' ';

  // Print the direct callee if present as a function attribute, or an indirect
  // callee (first operand) otherwise.
  if (isDirect)
    p.printSymbolName(callee.value());
  else
    p << getOperand(0);

  auto args = getOperands().drop_front(isDirect ? 0 : 1);
  p << '(' << args << ')';

  if (isVarArg)
    p << " vararg(" << calleeType << ")";

  p.printOptionalAttrDict(processFMFAttr((*this)->getAttrs()),
                          {getCConvAttrName(), "callee", "callee_type"});

  p << " : ";
  if (!isDirect)
    p << getOperand(0).getType() << ", ";

  // Reconstruct the function MLIR function type from operand and result types.
  p.printFunctionalType(args.getTypes(), getResultTypes());
}

/// Parses the type of a call operation and resolves the operands if the parsing
/// succeeds. Returns failure otherwise.
static ParseResult parseCallTypeAndResolveOperands(
    OpAsmParser &parser, OperationState &result, bool isDirect,
    ArrayRef<OpAsmParser::UnresolvedOperand> operands) {
  SMLoc trailingTypesLoc = parser.getCurrentLocation();
  SmallVector<Type> types;
  if (parser.parseColonTypeList(types))
    return failure();

  if (isDirect && types.size() != 1)
    return parser.emitError(trailingTypesLoc,
                            "expected direct call to have 1 trailing type");
  if (!isDirect && types.size() != 2)
    return parser.emitError(trailingTypesLoc,
                            "expected indirect call to have 2 trailing types");

  auto funcType = llvm::dyn_cast<FunctionType>(types.pop_back_val());
  if (!funcType)
    return parser.emitError(trailingTypesLoc,
                            "expected trailing function type");
  if (funcType.getNumResults() > 1)
    return parser.emitError(trailingTypesLoc,
                            "expected function with 0 or 1 result");
  if (funcType.getNumResults() == 1 &&
      llvm::isa<LLVM::LLVMVoidType>(funcType.getResult(0)))
    return parser.emitError(trailingTypesLoc,
                            "expected a non-void result type");

  // The head element of the types list matches the callee type for
  // indirect calls, while the types list is emtpy for direct calls.
  // Append the function input types to resolve the call operation
  // operands.
  llvm::append_range(types, funcType.getInputs());
  if (parser.resolveOperands(operands, types, parser.getNameLoc(),
                             result.operands))
    return failure();
  if (funcType.getNumResults() != 0)
    result.addTypes(funcType.getResults());

  return success();
}

/// Parses an optional function pointer operand before the call argument list
/// for indirect calls, or stops parsing at the function identifier otherwise.
static ParseResult parseOptionalCallFuncPtr(
    OpAsmParser &parser,
    SmallVectorImpl<OpAsmParser::UnresolvedOperand> &operands) {
  OpAsmParser::UnresolvedOperand funcPtrOperand;
  OptionalParseResult parseResult = parser.parseOptionalOperand(funcPtrOperand);
  if (parseResult.has_value()) {
    if (failed(*parseResult))
      return *parseResult;
    operands.push_back(funcPtrOperand);
  }
  return success();
}

// <operation> ::= `llvm.call` (cconv)? (function-id | ssa-use)
//                             `(` ssa-use-list `)`
//                             ( `vararg(` var-arg-func-type `)` )?
//                             attribute-dict? `:` (type `,`)? function-type
ParseResult CallOp::parse(OpAsmParser &parser, OperationState &result) {
  SymbolRefAttr funcAttr;
  TypeAttr calleeType;
  SmallVector<OpAsmParser::UnresolvedOperand> operands;

  // Default to C Calling Convention if no keyword is provided.
  result.addAttribute(
      getCConvAttrName(result.name),
      CConvAttr::get(parser.getContext(), parseOptionalLLVMKeyword<CConv>(
                                              parser, result, LLVM::CConv::C)));

  // Parse a function pointer for indirect calls.
  if (parseOptionalCallFuncPtr(parser, operands))
    return failure();
  bool isDirect = operands.empty();

  // Parse a function identifier for direct calls.
  if (isDirect)
    if (parser.parseAttribute(funcAttr, "callee", result.attributes))
      return failure();

  // Parse the function arguments.
  if (parser.parseOperandList(operands, OpAsmParser::Delimiter::Paren))
    return failure();

  bool isVarArg = parser.parseOptionalKeyword("vararg").succeeded();
  if (isVarArg) {
    if (parser.parseLParen().failed() ||
        parser.parseAttribute(calleeType, "callee_type", result.attributes)
            .failed() ||
        parser.parseRParen().failed())
      return failure();
  }

  if (parser.parseOptionalAttrDict(result.attributes))
    return failure();

  // Parse the trailing type list and resolve the operands.
  return parseCallTypeAndResolveOperands(parser, result, isDirect, operands);
}

LLVMFunctionType CallOp::getCalleeFunctionType() {
  if (getCalleeType())
    return *getCalleeType();
  return getLLVMFuncType(getContext(), getResultTypes(), getArgOperands());
}

///===---------------------------------------------------------------------===//
/// LLVM::InvokeOp
///===---------------------------------------------------------------------===//

void InvokeOp::build(OpBuilder &builder, OperationState &state, LLVMFuncOp func,
                     ValueRange ops, Block *normal, ValueRange normalOps,
                     Block *unwind, ValueRange unwindOps) {
  auto calleeType = func.getFunctionType();
  build(builder, state, getCallOpResultTypes(calleeType),
        TypeAttr::get(calleeType), SymbolRefAttr::get(func), ops, normalOps,
        unwindOps, nullptr, nullptr, normal, unwind);
}

void InvokeOp::build(OpBuilder &builder, OperationState &state, TypeRange tys,
                     FlatSymbolRefAttr callee, ValueRange ops, Block *normal,
                     ValueRange normalOps, Block *unwind,
                     ValueRange unwindOps) {
  build(builder, state, tys,
        TypeAttr::get(getLLVMFuncType(builder.getContext(), tys, ops)), callee,
        ops, normalOps, unwindOps, nullptr, nullptr, normal, unwind);
}

void InvokeOp::build(OpBuilder &builder, OperationState &state,
                     LLVMFunctionType calleeType, FlatSymbolRefAttr callee,
                     ValueRange ops, Block *normal, ValueRange normalOps,
                     Block *unwind, ValueRange unwindOps) {
  build(builder, state, getCallOpResultTypes(calleeType),
        TypeAttr::get(calleeType), callee, ops, normalOps, unwindOps, nullptr,
        nullptr, normal, unwind);
}

SuccessorOperands InvokeOp::getSuccessorOperands(unsigned index) {
  assert(index < getNumSuccessors() && "invalid successor index");
  return SuccessorOperands(index == 0 ? getNormalDestOperandsMutable()
                                      : getUnwindDestOperandsMutable());
}

CallInterfaceCallable InvokeOp::getCallableForCallee() {
  // Direct call.
  if (FlatSymbolRefAttr calleeAttr = getCalleeAttr())
    return calleeAttr;
  // Indirect call, callee Value is the first operand.
  return getOperand(0);
}

void InvokeOp::setCalleeFromCallable(CallInterfaceCallable callee) {
  // Direct call.
  if (FlatSymbolRefAttr calleeAttr = getCalleeAttr()) {
    auto symRef = callee.get<SymbolRefAttr>();
    return setCalleeAttr(cast<FlatSymbolRefAttr>(symRef));
  }
  // Indirect call, callee Value is the first operand.
  return setOperand(0, callee.get<Value>());
}

Operation::operand_range InvokeOp::getArgOperands() {
  return getOperands().drop_front(getCallee().has_value() ? 0 : 1);
}

MutableOperandRange InvokeOp::getArgOperandsMutable() {
  return MutableOperandRange(*this, getCallee().has_value() ? 0 : 1,
                             getCalleeOperands().size());
}

LogicalResult InvokeOp::verify() {
  if (getNumResults() > 1)
    return emitOpError("must have 0 or 1 result");

  Block *unwindDest = getUnwindDest();
  if (unwindDest->empty())
    return emitError("must have at least one operation in unwind destination");

  // In unwind destination, first operation must be LandingpadOp
  if (!isa<LandingpadOp>(unwindDest->front()))
    return emitError("first operation in unwind destination should be a "
                     "llvm.landingpad operation");

  return success();
}

void InvokeOp::print(OpAsmPrinter &p) {
  auto callee = getCallee();
  bool isDirect = callee.has_value();

  LLVMFunctionType calleeType;
  bool isVarArg = false;

  if (std::optional<LLVMFunctionType> optionalCalleeType = getCalleeType()) {
    calleeType = *optionalCalleeType;
    isVarArg = calleeType.isVarArg();
  }

  p << ' ';

  // Print calling convention.
  if (getCConv() != LLVM::CConv::C)
    p << stringifyCConv(getCConv()) << ' ';

  // Either function name or pointer
  if (isDirect)
    p.printSymbolName(callee.value());
  else
    p << getOperand(0);

  p << '(' << getOperands().drop_front(isDirect ? 0 : 1) << ')';
  p << " to ";
  p.printSuccessorAndUseList(getNormalDest(), getNormalDestOperands());
  p << " unwind ";
  p.printSuccessorAndUseList(getUnwindDest(), getUnwindDestOperands());

  if (isVarArg)
    p << " vararg(" << calleeType << ")";

  p.printOptionalAttrDict((*this)->getAttrs(),
                          {InvokeOp::getOperandSegmentSizeAttr(), "callee",
                           "callee_type", InvokeOp::getCConvAttrName()});

  p << " : ";
  if (!isDirect)
    p << getOperand(0).getType() << ", ";
  p.printFunctionalType(llvm::drop_begin(getOperandTypes(), isDirect ? 0 : 1),
                        getResultTypes());
}

// <operation> ::= `llvm.invoke` (cconv)? (function-id | ssa-use)
//                  `(` ssa-use-list `)`
//                  `to` bb-id (`[` ssa-use-and-type-list `]`)?
//                  `unwind` bb-id (`[` ssa-use-and-type-list `]`)?
//                  ( `vararg(` var-arg-func-type `)` )?
//                  attribute-dict? `:` (type `,`)? function-type
ParseResult InvokeOp::parse(OpAsmParser &parser, OperationState &result) {
  SmallVector<OpAsmParser::UnresolvedOperand, 8> operands;
  SymbolRefAttr funcAttr;
  TypeAttr calleeType;
  Block *normalDest, *unwindDest;
  SmallVector<Value, 4> normalOperands, unwindOperands;
  Builder &builder = parser.getBuilder();

  // Default to C Calling Convention if no keyword is provided.
  result.addAttribute(
      getCConvAttrName(result.name),
      CConvAttr::get(parser.getContext(), parseOptionalLLVMKeyword<CConv>(
                                              parser, result, LLVM::CConv::C)));

  // Parse a function pointer for indirect calls.
  if (parseOptionalCallFuncPtr(parser, operands))
    return failure();
  bool isDirect = operands.empty();

  // Parse a function identifier for direct calls.
  if (isDirect && parser.parseAttribute(funcAttr, "callee", result.attributes))
    return failure();

  // Parse the function arguments.
  if (parser.parseOperandList(operands, OpAsmParser::Delimiter::Paren) ||
      parser.parseKeyword("to") ||
      parser.parseSuccessorAndUseList(normalDest, normalOperands) ||
      parser.parseKeyword("unwind") ||
      parser.parseSuccessorAndUseList(unwindDest, unwindOperands))
    return failure();

  bool isVarArg = parser.parseOptionalKeyword("vararg").succeeded();
  if (isVarArg) {
    if (parser.parseLParen().failed() ||
        parser.parseAttribute(calleeType, "callee_type", result.attributes)
            .failed() ||
        parser.parseRParen().failed())
      return failure();
  }

  if (parser.parseOptionalAttrDict(result.attributes))
    return failure();

  // Parse the trailing type list and resolve the function operands.
  if (parseCallTypeAndResolveOperands(parser, result, isDirect, operands))
    return failure();

  result.addSuccessors({normalDest, unwindDest});
  result.addOperands(normalOperands);
  result.addOperands(unwindOperands);

  result.addAttribute(InvokeOp::getOperandSegmentSizeAttr(),
                      builder.getDenseI32ArrayAttr(
                          {static_cast<int32_t>(operands.size()),
                           static_cast<int32_t>(normalOperands.size()),
                           static_cast<int32_t>(unwindOperands.size())}));
  return success();
}

LLVMFunctionType InvokeOp::getCalleeFunctionType() {
  if (getCalleeType())
    return *getCalleeType();
  return getLLVMFuncType(getContext(), getResultTypes(), getArgOperands());
}

///===----------------------------------------------------------------------===//
/// Verifying/Printing/Parsing for LLVM::LandingpadOp.
///===----------------------------------------------------------------------===//

LogicalResult LandingpadOp::verify() {
  Value value;
  if (LLVMFuncOp func = (*this)->getParentOfType<LLVMFuncOp>()) {
    if (!func.getPersonality())
      return emitError(
          "llvm.landingpad needs to be in a function with a personality");
  }

  // Consistency of llvm.landingpad result types is checked in
  // LLVMFuncOp::verify().

  if (!getCleanup() && getOperands().empty())
    return emitError("landingpad instruction expects at least one clause or "
                     "cleanup attribute");

  for (unsigned idx = 0, ie = getNumOperands(); idx < ie; idx++) {
    value = getOperand(idx);
    bool isFilter = llvm::isa<LLVMArrayType>(value.getType());
    if (isFilter) {
      // FIXME: Verify filter clauses when arrays are appropriately handled
    } else {
      // catch - global addresses only.
      // Bitcast ops should have global addresses as their args.
      if (auto bcOp = value.getDefiningOp<BitcastOp>()) {
        if (auto addrOp = bcOp.getArg().getDefiningOp<AddressOfOp>())
          continue;
        return emitError("constant clauses expected").attachNote(bcOp.getLoc())
               << "global addresses expected as operand to "
                  "bitcast used in clauses for landingpad";
      }
      // ZeroOp and AddressOfOp allowed
      if (value.getDefiningOp<ZeroOp>())
        continue;
      if (value.getDefiningOp<AddressOfOp>())
        continue;
      return emitError("clause #")
             << idx << " is not a known constant - null, addressof, bitcast";
    }
  }
  return success();
}

void LandingpadOp::print(OpAsmPrinter &p) {
  p << (getCleanup() ? " cleanup " : " ");

  // Clauses
  for (auto value : getOperands()) {
    // Similar to llvm - if clause is an array type then it is filter
    // clause else catch clause
    bool isArrayTy = llvm::isa<LLVMArrayType>(value.getType());
    p << '(' << (isArrayTy ? "filter " : "catch ") << value << " : "
      << value.getType() << ") ";
  }

  p.printOptionalAttrDict((*this)->getAttrs(), {"cleanup"});

  p << ": " << getType();
}

// <operation> ::= `llvm.landingpad` `cleanup`?
//                 ((`catch` | `filter`) operand-type ssa-use)* attribute-dict?
ParseResult LandingpadOp::parse(OpAsmParser &parser, OperationState &result) {
  // Check for cleanup
  if (succeeded(parser.parseOptionalKeyword("cleanup")))
    result.addAttribute("cleanup", parser.getBuilder().getUnitAttr());

  // Parse clauses with types
  while (succeeded(parser.parseOptionalLParen()) &&
         (succeeded(parser.parseOptionalKeyword("filter")) ||
          succeeded(parser.parseOptionalKeyword("catch")))) {
    OpAsmParser::UnresolvedOperand operand;
    Type ty;
    if (parser.parseOperand(operand) || parser.parseColon() ||
        parser.parseType(ty) ||
        parser.resolveOperand(operand, ty, result.operands) ||
        parser.parseRParen())
      return failure();
  }

  Type type;
  if (parser.parseColon() || parser.parseType(type))
    return failure();

  result.addTypes(type);
  return success();
}

//===----------------------------------------------------------------------===//
// ExtractValueOp
//===----------------------------------------------------------------------===//

/// Extract the type at `position` in the LLVM IR aggregate type
/// `containerType`. Each element of `position` is an index into a nested
/// aggregate type. Return the resulting type or emit an error.
static Type getInsertExtractValueElementType(
    function_ref<InFlightDiagnostic(StringRef)> emitError, Type containerType,
    ArrayRef<int64_t> position) {
  Type llvmType = containerType;
  if (!isCompatibleType(containerType)) {
    emitError("expected LLVM IR Dialect type, got ") << containerType;
    return {};
  }

  // Infer the element type from the structure type: iteratively step inside the
  // type by taking the element type, indexed by the position attribute for
  // structures.  Check the position index before accessing, it is supposed to
  // be in bounds.
  for (int64_t idx : position) {
    if (auto arrayType = llvm::dyn_cast<LLVMArrayType>(llvmType)) {
      if (idx < 0 || static_cast<unsigned>(idx) >= arrayType.getNumElements()) {
        emitError("position out of bounds: ") << idx;
        return {};
      }
      llvmType = arrayType.getElementType();
    } else if (auto structType = llvm::dyn_cast<LLVMStructType>(llvmType)) {
      if (idx < 0 ||
          static_cast<unsigned>(idx) >= structType.getBody().size()) {
        emitError("position out of bounds: ") << idx;
        return {};
      }
      llvmType = structType.getBody()[idx];
    } else {
      emitError("expected LLVM IR structure/array type, got: ") << llvmType;
      return {};
    }
  }
  return llvmType;
}

/// Extract the type at `position` in the wrapped LLVM IR aggregate type
/// `containerType`.
static Type getInsertExtractValueElementType(Type llvmType,
                                             ArrayRef<int64_t> position) {
  for (int64_t idx : position) {
    if (auto structType = llvm::dyn_cast<LLVMStructType>(llvmType))
      llvmType = structType.getBody()[idx];
    else
      llvmType = llvm::cast<LLVMArrayType>(llvmType).getElementType();
  }
  return llvmType;
}

OpFoldResult LLVM::ExtractValueOp::fold(FoldAdaptor adaptor) {
  auto insertValueOp = getContainer().getDefiningOp<InsertValueOp>();
  OpFoldResult result = {};
  while (insertValueOp) {
    if (getPosition() == insertValueOp.getPosition())
      return insertValueOp.getValue();
    unsigned min =
        std::min(getPosition().size(), insertValueOp.getPosition().size());
    // If one is fully prefix of the other, stop propagating back as it will
    // miss dependencies. For instance, %3 should not fold to %f0 in the
    // following example:
    // ```
    //   %1 = llvm.insertvalue %f0, %0[0, 0] :
    //     !llvm.array<4 x !llvm.array<4 x f32>>
    //   %2 = llvm.insertvalue %arr, %1[0] :
    //     !llvm.array<4 x !llvm.array<4 x f32>>
    //   %3 = llvm.extractvalue %2[0, 0] : !llvm.array<4 x !llvm.array<4 x f32>>
    // ```
    if (getPosition().take_front(min) ==
        insertValueOp.getPosition().take_front(min))
      return result;

    // If neither a prefix, nor the exact position, we can extract out of the
    // value being inserted into. Moreover, we can try again if that operand
    // is itself an insertvalue expression.
    getContainerMutable().assign(insertValueOp.getContainer());
    result = getResult();
    insertValueOp = insertValueOp.getContainer().getDefiningOp<InsertValueOp>();
  }
  return result;
}

LogicalResult ExtractValueOp::verify() {
  auto emitError = [this](StringRef msg) { return emitOpError(msg); };
  Type valueType = getInsertExtractValueElementType(
      emitError, getContainer().getType(), getPosition());
  if (!valueType)
    return failure();

  if (getRes().getType() != valueType)
    return emitOpError() << "Type mismatch: extracting from "
                         << getContainer().getType() << " should produce "
                         << valueType << " but this op returns "
                         << getRes().getType();
  return success();
}

void ExtractValueOp::build(OpBuilder &builder, OperationState &state,
                           Value container, ArrayRef<int64_t> position) {
  build(builder, state,
        getInsertExtractValueElementType(container.getType(), position),
        container, builder.getAttr<DenseI64ArrayAttr>(position));
}

//===----------------------------------------------------------------------===//
// InsertValueOp
//===----------------------------------------------------------------------===//

/// Infer the value type from the container type and position.
static ParseResult
parseInsertExtractValueElementType(AsmParser &parser, Type &valueType,
                                   Type containerType,
                                   DenseI64ArrayAttr position) {
  valueType = getInsertExtractValueElementType(
      [&](StringRef msg) {
        return parser.emitError(parser.getCurrentLocation(), msg);
      },
      containerType, position.asArrayRef());
  return success(!!valueType);
}

/// Nothing to print for an inferred type.
static void printInsertExtractValueElementType(AsmPrinter &printer,
                                               Operation *op, Type valueType,
                                               Type containerType,
                                               DenseI64ArrayAttr position) {}

LogicalResult InsertValueOp::verify() {
  auto emitError = [this](StringRef msg) { return emitOpError(msg); };
  Type valueType = getInsertExtractValueElementType(
      emitError, getContainer().getType(), getPosition());
  if (!valueType)
    return failure();

  if (getValue().getType() != valueType)
    return emitOpError() << "Type mismatch: cannot insert "
                         << getValue().getType() << " into "
                         << getContainer().getType();

  return success();
}

//===----------------------------------------------------------------------===//
// ReturnOp
//===----------------------------------------------------------------------===//

LogicalResult ReturnOp::verify() {
  auto parent = (*this)->getParentOfType<LLVMFuncOp>();
  if (!parent)
    return success();

  Type expectedType = parent.getFunctionType().getReturnType();
  if (llvm::isa<LLVMVoidType>(expectedType)) {
    if (!getArg())
      return success();
    InFlightDiagnostic diag = emitOpError("expected no operands");
    diag.attachNote(parent->getLoc()) << "when returning from function";
    return diag;
  }
  if (!getArg()) {
    if (llvm::isa<LLVMVoidType>(expectedType))
      return success();
    InFlightDiagnostic diag = emitOpError("expected 1 operand");
    diag.attachNote(parent->getLoc()) << "when returning from function";
    return diag;
  }
  if (expectedType != getArg().getType()) {
    InFlightDiagnostic diag = emitOpError("mismatching result types");
    diag.attachNote(parent->getLoc()) << "when returning from function";
    return diag;
  }
  return success();
}

//===----------------------------------------------------------------------===//
// LLVM::AddressOfOp.
//===----------------------------------------------------------------------===//

static Operation *parentLLVMModule(Operation *op) {
  Operation *module = op->getParentOp();
  while (module && !satisfiesLLVMModule(module))
    module = module->getParentOp();
  assert(module && "unexpected operation outside of a module");
  return module;
}

GlobalOp AddressOfOp::getGlobal(SymbolTableCollection &symbolTable) {
  return dyn_cast_or_null<GlobalOp>(
      symbolTable.lookupSymbolIn(parentLLVMModule(*this), getGlobalNameAttr()));
}

LLVMFuncOp AddressOfOp::getFunction(SymbolTableCollection &symbolTable) {
  return dyn_cast_or_null<LLVMFuncOp>(
      symbolTable.lookupSymbolIn(parentLLVMModule(*this), getGlobalNameAttr()));
}

LogicalResult
AddressOfOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
  Operation *symbol =
      symbolTable.lookupSymbolIn(parentLLVMModule(*this), getGlobalNameAttr());

  auto global = dyn_cast_or_null<GlobalOp>(symbol);
  auto function = dyn_cast_or_null<LLVMFuncOp>(symbol);

  if (!global && !function)
    return emitOpError(
        "must reference a global defined by 'llvm.mlir.global' or 'llvm.func'");

  LLVMPointerType type = getType();
  if (global && global.getAddrSpace() != type.getAddressSpace())
    return emitOpError("pointer address space must match address space of the "
                       "referenced global");

  return success();
}

// AddressOfOp constant-folds to the global symbol name.
OpFoldResult LLVM::AddressOfOp::fold(FoldAdaptor) {
  return getGlobalNameAttr();
}

//===----------------------------------------------------------------------===//
// Verifier for LLVM::ComdatOp.
//===----------------------------------------------------------------------===//

void ComdatOp::build(OpBuilder &builder, OperationState &result,
                     StringRef symName) {
  result.addAttribute(getSymNameAttrName(result.name),
                      builder.getStringAttr(symName));
  Region *body = result.addRegion();
  body->emplaceBlock();
}

LogicalResult ComdatOp::verifyRegions() {
  Region &body = getBody();
  for (Operation &op : body.getOps())
    if (!isa<ComdatSelectorOp>(op))
      return op.emitError(
          "only comdat selector symbols can appear in a comdat region");

  return success();
}

//===----------------------------------------------------------------------===//
// Builder, printer and verifier for LLVM::GlobalOp.
//===----------------------------------------------------------------------===//

void GlobalOp::build(OpBuilder &builder, OperationState &result, Type type,
                     bool isConstant, Linkage linkage, StringRef name,
                     Attribute value, uint64_t alignment, unsigned addrSpace,
                     bool dsoLocal, bool threadLocal, SymbolRefAttr comdat,
                     ArrayRef<NamedAttribute> attrs,
                     DIGlobalVariableExpressionAttr dbgExpr) {
  result.addAttribute(getSymNameAttrName(result.name),
                      builder.getStringAttr(name));
  result.addAttribute(getGlobalTypeAttrName(result.name), TypeAttr::get(type));
  if (isConstant)
    result.addAttribute(getConstantAttrName(result.name),
                        builder.getUnitAttr());
  if (value)
    result.addAttribute(getValueAttrName(result.name), value);
  if (dsoLocal)
    result.addAttribute(getDsoLocalAttrName(result.name),
                        builder.getUnitAttr());
  if (threadLocal)
    result.addAttribute(getThreadLocal_AttrName(result.name),
                        builder.getUnitAttr());
  if (comdat)
    result.addAttribute(getComdatAttrName(result.name), comdat);

  // Only add an alignment attribute if the "alignment" input
  // is different from 0. The value must also be a power of two, but
  // this is tested in GlobalOp::verify, not here.
  if (alignment != 0)
    result.addAttribute(getAlignmentAttrName(result.name),
                        builder.getI64IntegerAttr(alignment));

  result.addAttribute(getLinkageAttrName(result.name),
                      LinkageAttr::get(builder.getContext(), linkage));
  if (addrSpace != 0)
    result.addAttribute(getAddrSpaceAttrName(result.name),
                        builder.getI32IntegerAttr(addrSpace));
  result.attributes.append(attrs.begin(), attrs.end());

  if (dbgExpr)
    result.addAttribute(getDbgExprAttrName(result.name), dbgExpr);

  result.addRegion();
}

void GlobalOp::print(OpAsmPrinter &p) {
  p << ' ' << stringifyLinkage(getLinkage()) << ' ';
  StringRef visibility = stringifyVisibility(getVisibility_());
  if (!visibility.empty())
    p << visibility << ' ';
  if (getThreadLocal_())
    p << "thread_local ";
  if (auto unnamedAddr = getUnnamedAddr()) {
    StringRef str = stringifyUnnamedAddr(*unnamedAddr);
    if (!str.empty())
      p << str << ' ';
  }
  if (getConstant())
    p << "constant ";
  p.printSymbolName(getSymName());
  p << '(';
  if (auto value = getValueOrNull())
    p.printAttribute(value);
  p << ')';
  if (auto comdat = getComdat())
    p << " comdat(" << *comdat << ')';

  // Note that the alignment attribute is printed using the
  // default syntax here, even though it is an inherent attribute
  // (as defined in https://mlir.llvm.org/docs/LangRef/#attributes)
  p.printOptionalAttrDict((*this)->getAttrs(),
                          {SymbolTable::getSymbolAttrName(),
                           getGlobalTypeAttrName(), getConstantAttrName(),
                           getValueAttrName(), getLinkageAttrName(),
                           getUnnamedAddrAttrName(), getThreadLocal_AttrName(),
                           getVisibility_AttrName(), getComdatAttrName(),
                           getUnnamedAddrAttrName()});

  // Print the trailing type unless it's a string global.
  if (llvm::dyn_cast_or_null<StringAttr>(getValueOrNull()))
    return;
  p << " : " << getType();

  Region &initializer = getInitializerRegion();
  if (!initializer.empty()) {
    p << ' ';
    p.printRegion(initializer, /*printEntryBlockArgs=*/false);
  }
}

static LogicalResult verifyComdat(Operation *op,
                                  std::optional<SymbolRefAttr> attr) {
  if (!attr)
    return success();

  auto *comdatSelector = SymbolTable::lookupNearestSymbolFrom(op, *attr);
  if (!isa_and_nonnull<ComdatSelectorOp>(comdatSelector))
    return op->emitError() << "expected comdat symbol";

  return success();
}

// operation ::= `llvm.mlir.global` linkage? visibility?
//               (`unnamed_addr` | `local_unnamed_addr`)?
//               `thread_local`? `constant`? `@` identifier
//               `(` attribute? `)` (`comdat(` symbol-ref-id `)`)?
//               attribute-list? (`:` type)? region?
//
// The type can be omitted for string attributes, in which case it will be
// inferred from the value of the string as [strlen(value) x i8].
ParseResult GlobalOp::parse(OpAsmParser &parser, OperationState &result) {
  MLIRContext *ctx = parser.getContext();
  // Parse optional linkage, default to External.
  result.addAttribute(getLinkageAttrName(result.name),
                      LLVM::LinkageAttr::get(
                          ctx, parseOptionalLLVMKeyword<Linkage>(
                                   parser, result, LLVM::Linkage::External)));

  // Parse optional visibility, default to Default.
  result.addAttribute(getVisibility_AttrName(result.name),
                      parser.getBuilder().getI64IntegerAttr(
                          parseOptionalLLVMKeyword<LLVM::Visibility, int64_t>(
                              parser, result, LLVM::Visibility::Default)));

  // Parse optional UnnamedAddr, default to None.
  result.addAttribute(getUnnamedAddrAttrName(result.name),
                      parser.getBuilder().getI64IntegerAttr(
                          parseOptionalLLVMKeyword<UnnamedAddr, int64_t>(
                              parser, result, LLVM::UnnamedAddr::None)));

  if (succeeded(parser.parseOptionalKeyword("thread_local")))
    result.addAttribute(getThreadLocal_AttrName(result.name),
                        parser.getBuilder().getUnitAttr());

  if (succeeded(parser.parseOptionalKeyword("constant")))
    result.addAttribute(getConstantAttrName(result.name),
                        parser.getBuilder().getUnitAttr());

  StringAttr name;
  if (parser.parseSymbolName(name, getSymNameAttrName(result.name),
                             result.attributes) ||
      parser.parseLParen())
    return failure();

  Attribute value;
  if (parser.parseOptionalRParen()) {
    if (parser.parseAttribute(value, getValueAttrName(result.name),
                              result.attributes) ||
        parser.parseRParen())
      return failure();
  }

  if (succeeded(parser.parseOptionalKeyword("comdat"))) {
    SymbolRefAttr comdat;
    if (parser.parseLParen() || parser.parseAttribute(comdat) ||
        parser.parseRParen())
      return failure();

    result.addAttribute(getComdatAttrName(result.name), comdat);
  }

  SmallVector<Type, 1> types;
  if (parser.parseOptionalAttrDict(result.attributes) ||
      parser.parseOptionalColonTypeList(types))
    return failure();

  if (types.size() > 1)
    return parser.emitError(parser.getNameLoc(), "expected zero or one type");

  Region &initRegion = *result.addRegion();
  if (types.empty()) {
    if (auto strAttr = llvm::dyn_cast_or_null<StringAttr>(value)) {
      MLIRContext *context = parser.getContext();
      auto arrayType = LLVM::LLVMArrayType::get(IntegerType::get(context, 8),
                                                strAttr.getValue().size());
      types.push_back(arrayType);
    } else {
      return parser.emitError(parser.getNameLoc(),
                              "type can only be omitted for string globals");
    }
  } else {
    OptionalParseResult parseResult =
        parser.parseOptionalRegion(initRegion, /*arguments=*/{},
                                   /*argTypes=*/{});
    if (parseResult.has_value() && failed(*parseResult))
      return failure();
  }

  result.addAttribute(getGlobalTypeAttrName(result.name),
                      TypeAttr::get(types[0]));
  return success();
}

static bool isZeroAttribute(Attribute value) {
  if (auto intValue = llvm::dyn_cast<IntegerAttr>(value))
    return intValue.getValue().isZero();
  if (auto fpValue = llvm::dyn_cast<FloatAttr>(value))
    return fpValue.getValue().isZero();
  if (auto splatValue = llvm::dyn_cast<SplatElementsAttr>(value))
    return isZeroAttribute(splatValue.getSplatValue<Attribute>());
  if (auto elementsValue = llvm::dyn_cast<ElementsAttr>(value))
    return llvm::all_of(elementsValue.getValues<Attribute>(), isZeroAttribute);
  if (auto arrayValue = llvm::dyn_cast<ArrayAttr>(value))
    return llvm::all_of(arrayValue.getValue(), isZeroAttribute);
  return false;
}

LogicalResult GlobalOp::verify() {
  bool validType = isCompatibleOuterType(getType())
                       ? !llvm::isa<LLVMVoidType, LLVMTokenType,
                                    LLVMMetadataType, LLVMLabelType>(getType())
                       : llvm::isa<PointerElementTypeInterface>(getType());
  if (!validType)
    return emitOpError(
        "expects type to be a valid element type for an LLVM global");
  if ((*this)->getParentOp() && !satisfiesLLVMModule((*this)->getParentOp()))
    return emitOpError("must appear at the module level");

  if (auto strAttr = llvm::dyn_cast_or_null<StringAttr>(getValueOrNull())) {
    auto type = llvm::dyn_cast<LLVMArrayType>(getType());
    IntegerType elementType =
        type ? llvm::dyn_cast<IntegerType>(type.getElementType()) : nullptr;
    if (!elementType || elementType.getWidth() != 8 ||
        type.getNumElements() != strAttr.getValue().size())
      return emitOpError(
          "requires an i8 array type of the length equal to that of the string "
          "attribute");
  }

  if (auto targetExtType = dyn_cast<LLVMTargetExtType>(getType())) {
    if (!targetExtType.hasProperty(LLVMTargetExtType::CanBeGlobal))
      return emitOpError()
             << "this target extension type cannot be used in a global";

    if (Attribute value = getValueOrNull())
      return emitOpError() << "global with target extension type can only be "
                              "initialized with zero-initializer";
  }

  if (getLinkage() == Linkage::Common) {
    if (Attribute value = getValueOrNull()) {
      if (!isZeroAttribute(value)) {
        return emitOpError()
               << "expected zero value for '"
               << stringifyLinkage(Linkage::Common) << "' linkage";
      }
    }
  }

  if (getLinkage() == Linkage::Appending) {
    if (!llvm::isa<LLVMArrayType>(getType())) {
      return emitOpError() << "expected array type for '"
                           << stringifyLinkage(Linkage::Appending)
                           << "' linkage";
    }
  }

  if (failed(verifyComdat(*this, getComdat())))
    return failure();

  std::optional<uint64_t> alignAttr = getAlignment();
  if (alignAttr.has_value()) {
    uint64_t value = alignAttr.value();
    if (!llvm::isPowerOf2_64(value))
      return emitError() << "alignment attribute is not a power of 2";
  }

  return success();
}

LogicalResult GlobalOp::verifyRegions() {
  if (Block *b = getInitializerBlock()) {
    ReturnOp ret = cast<ReturnOp>(b->getTerminator());
    if (ret.operand_type_begin() == ret.operand_type_end())
      return emitOpError("initializer region cannot return void");
    if (*ret.operand_type_begin() != getType())
      return emitOpError("initializer region type ")
             << *ret.operand_type_begin() << " does not match global type "
             << getType();

    for (Operation &op : *b) {
      auto iface = dyn_cast<MemoryEffectOpInterface>(op);
      if (!iface || !iface.hasNoEffect())
        return op.emitError()
               << "ops with side effects not allowed in global initializers";
    }

    if (getValueOrNull())
      return emitOpError("cannot have both initializer value and region");
  }

  return success();
}

//===----------------------------------------------------------------------===//
// LLVM::GlobalCtorsOp
//===----------------------------------------------------------------------===//

LogicalResult
GlobalCtorsOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
  for (Attribute ctor : getCtors()) {
    if (failed(verifySymbolAttrUse(llvm::cast<FlatSymbolRefAttr>(ctor), *this,
                                   symbolTable)))
      return failure();
  }
  return success();
}

LogicalResult GlobalCtorsOp::verify() {
  if (getCtors().size() != getPriorities().size())
    return emitError(
        "mismatch between the number of ctors and the number of priorities");
  return success();
}

//===----------------------------------------------------------------------===//
// LLVM::GlobalDtorsOp
//===----------------------------------------------------------------------===//

LogicalResult
GlobalDtorsOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
  for (Attribute dtor : getDtors()) {
    if (failed(verifySymbolAttrUse(llvm::cast<FlatSymbolRefAttr>(dtor), *this,
                                   symbolTable)))
      return failure();
  }
  return success();
}

LogicalResult GlobalDtorsOp::verify() {
  if (getDtors().size() != getPriorities().size())
    return emitError(
        "mismatch between the number of dtors and the number of priorities");
  return success();
}

//===----------------------------------------------------------------------===//
// ShuffleVectorOp
//===----------------------------------------------------------------------===//

void ShuffleVectorOp::build(OpBuilder &builder, OperationState &state, Value v1,
                            Value v2, DenseI32ArrayAttr mask,
                            ArrayRef<NamedAttribute> attrs) {
  auto containerType = v1.getType();
  auto vType = LLVM::getVectorType(LLVM::getVectorElementType(containerType),
                                   mask.size(),
                                   LLVM::isScalableVectorType(containerType));
  build(builder, state, vType, v1, v2, mask);
  state.addAttributes(attrs);
}

void ShuffleVectorOp::build(OpBuilder &builder, OperationState &state, Value v1,
                            Value v2, ArrayRef<int32_t> mask) {
  build(builder, state, v1, v2, builder.getDenseI32ArrayAttr(mask));
}

/// Build the result type of a shuffle vector operation.
static ParseResult parseShuffleType(AsmParser &parser, Type v1Type,
                                    Type &resType, DenseI32ArrayAttr mask) {
  if (!LLVM::isCompatibleVectorType(v1Type))
    return parser.emitError(parser.getCurrentLocation(),
                            "expected an LLVM compatible vector type");
  resType = LLVM::getVectorType(LLVM::getVectorElementType(v1Type), mask.size(),
                                LLVM::isScalableVectorType(v1Type));
  return success();
}

/// Nothing to do when the result type is inferred.
static void printShuffleType(AsmPrinter &printer, Operation *op, Type v1Type,
                             Type resType, DenseI32ArrayAttr mask) {}

LogicalResult ShuffleVectorOp::verify() {
  if (LLVM::isScalableVectorType(getV1().getType()) &&
      llvm::any_of(getMask(), [](int32_t v) { return v != 0; }))
    return emitOpError("expected a splat operation for scalable vectors");
  return success();
}

//===----------------------------------------------------------------------===//
// Implementations for LLVM::LLVMFuncOp.
//===----------------------------------------------------------------------===//

// Add the entry block to the function.
Block *LLVMFuncOp::addEntryBlock(OpBuilder &builder) {
  assert(empty() && "function already has an entry block");
  OpBuilder::InsertionGuard g(builder);
  Block *entry = builder.createBlock(&getBody());

  // FIXME: Allow passing in proper locations for the entry arguments.
  LLVMFunctionType type = getFunctionType();
  for (unsigned i = 0, e = type.getNumParams(); i < e; ++i)
    entry->addArgument(type.getParamType(i), getLoc());
  return entry;
}

void LLVMFuncOp::build(OpBuilder &builder, OperationState &result,
                       StringRef name, Type type, LLVM::Linkage linkage,
                       bool dsoLocal, CConv cconv, SymbolRefAttr comdat,
                       ArrayRef<NamedAttribute> attrs,
                       ArrayRef<DictionaryAttr> argAttrs,
                       std::optional<uint64_t> functionEntryCount) {
  result.addRegion();
  result.addAttribute(SymbolTable::getSymbolAttrName(),
                      builder.getStringAttr(name));
  result.addAttribute(getFunctionTypeAttrName(result.name),
                      TypeAttr::get(type));
  result.addAttribute(getLinkageAttrName(result.name),
                      LinkageAttr::get(builder.getContext(), linkage));
  result.addAttribute(getCConvAttrName(result.name),
                      CConvAttr::get(builder.getContext(), cconv));
  result.attributes.append(attrs.begin(), attrs.end());
  if (dsoLocal)
    result.addAttribute(getDsoLocalAttrName(result.name),
                        builder.getUnitAttr());
  if (comdat)
    result.addAttribute(getComdatAttrName(result.name), comdat);
  if (functionEntryCount)
    result.addAttribute(getFunctionEntryCountAttrName(result.name),
                        builder.getI64IntegerAttr(functionEntryCount.value()));
  if (argAttrs.empty())
    return;

  assert(llvm::cast<LLVMFunctionType>(type).getNumParams() == argAttrs.size() &&
         "expected as many argument attribute lists as arguments");
  function_interface_impl::addArgAndResultAttrs(
      builder, result, argAttrs, /*resultAttrs=*/std::nullopt,
      getArgAttrsAttrName(result.name), getResAttrsAttrName(result.name));
}

// Builds an LLVM function type from the given lists of input and output types.
// Returns a null type if any of the types provided are non-LLVM types, or if
// there is more than one output type.
static Type
buildLLVMFunctionType(OpAsmParser &parser, SMLoc loc, ArrayRef<Type> inputs,
                      ArrayRef<Type> outputs,
                      function_interface_impl::VariadicFlag variadicFlag) {
  Builder &b = parser.getBuilder();
  if (outputs.size() > 1) {
    parser.emitError(loc, "failed to construct function type: expected zero or "
                          "one function result");
    return {};
  }

  // Convert inputs to LLVM types, exit early on error.
  SmallVector<Type, 4> llvmInputs;
  for (auto t : inputs) {
    if (!isCompatibleType(t)) {
      parser.emitError(loc, "failed to construct function type: expected LLVM "
                            "type for function arguments");
      return {};
    }
    llvmInputs.push_back(t);
  }

  // No output is denoted as "void" in LLVM type system.
  Type llvmOutput =
      outputs.empty() ? LLVMVoidType::get(b.getContext()) : outputs.front();
  if (!isCompatibleType(llvmOutput)) {
    parser.emitError(loc, "failed to construct function type: expected LLVM "
                          "type for function results")
        << llvmOutput;
    return {};
  }
  return LLVMFunctionType::get(llvmOutput, llvmInputs,
                               variadicFlag.isVariadic());
}

// Parses an LLVM function.
//
// operation ::= `llvm.func` linkage? cconv? function-signature
//                (`comdat(` symbol-ref-id `)`)?
//                function-attributes?
//                function-body
//
ParseResult LLVMFuncOp::parse(OpAsmParser &parser, OperationState &result) {
  // Default to external linkage if no keyword is provided.
  result.addAttribute(
      getLinkageAttrName(result.name),
      LinkageAttr::get(parser.getContext(),
                       parseOptionalLLVMKeyword<Linkage>(
                           parser, result, LLVM::Linkage::External)));

  // Parse optional visibility, default to Default.
  result.addAttribute(getVisibility_AttrName(result.name),
                      parser.getBuilder().getI64IntegerAttr(
                          parseOptionalLLVMKeyword<LLVM::Visibility, int64_t>(
                              parser, result, LLVM::Visibility::Default)));

  // Parse optional UnnamedAddr, default to None.
  result.addAttribute(getUnnamedAddrAttrName(result.name),
                      parser.getBuilder().getI64IntegerAttr(
                          parseOptionalLLVMKeyword<UnnamedAddr, int64_t>(
                              parser, result, LLVM::UnnamedAddr::None)));

  // Default to C Calling Convention if no keyword is provided.
  result.addAttribute(
      getCConvAttrName(result.name),
      CConvAttr::get(parser.getContext(), parseOptionalLLVMKeyword<CConv>(
                                              parser, result, LLVM::CConv::C)));

  StringAttr nameAttr;
  SmallVector<OpAsmParser::Argument> entryArgs;
  SmallVector<DictionaryAttr> resultAttrs;
  SmallVector<Type> resultTypes;
  bool isVariadic;

  auto signatureLocation = parser.getCurrentLocation();
  if (parser.parseSymbolName(nameAttr, SymbolTable::getSymbolAttrName(),
                             result.attributes) ||
      function_interface_impl::parseFunctionSignature(
          parser, /*allowVariadic=*/true, entryArgs, isVariadic, resultTypes,
          resultAttrs))
    return failure();

  SmallVector<Type> argTypes;
  for (auto &arg : entryArgs)
    argTypes.push_back(arg.type);
  auto type =
      buildLLVMFunctionType(parser, signatureLocation, argTypes, resultTypes,
                            function_interface_impl::VariadicFlag(isVariadic));
  if (!type)
    return failure();
  result.addAttribute(getFunctionTypeAttrName(result.name),
                      TypeAttr::get(type));

  if (succeeded(parser.parseOptionalKeyword("vscale_range"))) {
    int64_t minRange, maxRange;
    if (parser.parseLParen() || parser.parseInteger(minRange) ||
        parser.parseComma() || parser.parseInteger(maxRange) ||
        parser.parseRParen())
      return failure();
    auto intTy = IntegerType::get(parser.getContext(), 32);
    result.addAttribute(
        getVscaleRangeAttrName(result.name),
        LLVM::VScaleRangeAttr::get(parser.getContext(),
                                   IntegerAttr::get(intTy, minRange),
                                   IntegerAttr::get(intTy, maxRange)));
  }
  // Parse the optional comdat selector.
  if (succeeded(parser.parseOptionalKeyword("comdat"))) {
    SymbolRefAttr comdat;
    if (parser.parseLParen() || parser.parseAttribute(comdat) ||
        parser.parseRParen())
      return failure();

    result.addAttribute(getComdatAttrName(result.name), comdat);
  }

  if (failed(parser.parseOptionalAttrDictWithKeyword(result.attributes)))
    return failure();
  function_interface_impl::addArgAndResultAttrs(
      parser.getBuilder(), result, entryArgs, resultAttrs,
      getArgAttrsAttrName(result.name), getResAttrsAttrName(result.name));

  auto *body = result.addRegion();
  OptionalParseResult parseResult =
      parser.parseOptionalRegion(*body, entryArgs);
  return failure(parseResult.has_value() && failed(*parseResult));
}

// Print the LLVMFuncOp. Collects argument and result types and passes them to
// helper functions. Drops "void" result since it cannot be parsed back. Skips
// the external linkage since it is the default value.
void LLVMFuncOp::print(OpAsmPrinter &p) {
  p << ' ';
  if (getLinkage() != LLVM::Linkage::External)
    p << stringifyLinkage(getLinkage()) << ' ';
  StringRef visibility = stringifyVisibility(getVisibility_());
  if (!visibility.empty())
    p << visibility << ' ';
  if (auto unnamedAddr = getUnnamedAddr()) {
    StringRef str = stringifyUnnamedAddr(*unnamedAddr);
    if (!str.empty())
      p << str << ' ';
  }
  if (getCConv() != LLVM::CConv::C)
    p << stringifyCConv(getCConv()) << ' ';

  p.printSymbolName(getName());

  LLVMFunctionType fnType = getFunctionType();
  SmallVector<Type, 8> argTypes;
  SmallVector<Type, 1> resTypes;
  argTypes.reserve(fnType.getNumParams());
  for (unsigned i = 0, e = fnType.getNumParams(); i < e; ++i)
    argTypes.push_back(fnType.getParamType(i));

  Type returnType = fnType.getReturnType();
  if (!llvm::isa<LLVMVoidType>(returnType))
    resTypes.push_back(returnType);

  function_interface_impl::printFunctionSignature(p, *this, argTypes,
                                                  isVarArg(), resTypes);

  // Print vscale range if present
  if (std::optional<VScaleRangeAttr> vscale = getVscaleRange())
    p << " vscale_range(" << vscale->getMinRange().getInt() << ", "
      << vscale->getMaxRange().getInt() << ')';

  // Print the optional comdat selector.
  if (auto comdat = getComdat())
    p << " comdat(" << *comdat << ')';

  function_interface_impl::printFunctionAttributes(
      p, *this,
      {getFunctionTypeAttrName(), getArgAttrsAttrName(), getResAttrsAttrName(),
       getLinkageAttrName(), getCConvAttrName(), getVisibility_AttrName(),
       getComdatAttrName(), getUnnamedAddrAttrName(),
       getVscaleRangeAttrName()});

  // Print the body if this is not an external function.
  Region &body = getBody();
  if (!body.empty()) {
    p << ' ';
    p.printRegion(body, /*printEntryBlockArgs=*/false,
                  /*printBlockTerminators=*/true);
  }
}

// Verifies LLVM- and implementation-specific properties of the LLVM func Op:
// - functions don't have 'common' linkage
// - external functions have 'external' or 'extern_weak' linkage;
// - vararg is (currently) only supported for external functions;
LogicalResult LLVMFuncOp::verify() {
  if (getLinkage() == LLVM::Linkage::Common)
    return emitOpError() << "functions cannot have '"
                         << stringifyLinkage(LLVM::Linkage::Common)
                         << "' linkage";

  if (failed(verifyComdat(*this, getComdat())))
    return failure();

  if (isExternal()) {
    if (getLinkage() != LLVM::Linkage::External &&
        getLinkage() != LLVM::Linkage::ExternWeak)
      return emitOpError() << "external functions must have '"
                           << stringifyLinkage(LLVM::Linkage::External)
                           << "' or '"
                           << stringifyLinkage(LLVM::Linkage::ExternWeak)
                           << "' linkage";
    return success();
  }

  Type landingpadResultTy;
  StringRef diagnosticMessage;
  bool isLandingpadTypeConsistent =
      !walk([&](Operation *op) {
         const auto checkType = [&](Type type, StringRef errorMessage) {
           if (!landingpadResultTy) {
             landingpadResultTy = type;
             return WalkResult::advance();
           }
           if (landingpadResultTy != type) {
             diagnosticMessage = errorMessage;
             return WalkResult::interrupt();
           }
           return WalkResult::advance();
         };
         return TypeSwitch<Operation *, WalkResult>(op)
             .Case<LandingpadOp>([&](auto landingpad) {
               constexpr StringLiteral errorMessage =
                   "'llvm.landingpad' should have a consistent result type "
                   "inside a function";
               return checkType(landingpad.getType(), errorMessage);
             })
             .Case<ResumeOp>([&](auto resume) {
               constexpr StringLiteral errorMessage =
                   "'llvm.resume' should have a consistent input type inside a "
                   "function";
               return checkType(resume.getValue().getType(), errorMessage);
             })
             .Default([](auto) { return WalkResult::skip(); });
       }).wasInterrupted();
  if (!isLandingpadTypeConsistent) {
    assert(!diagnosticMessage.empty() &&
           "Expecting a non-empty diagnostic message");
    return emitError(diagnosticMessage);
  }

  return success();
}

/// Verifies LLVM- and implementation-specific properties of the LLVM func Op:
/// - entry block arguments are of LLVM types.
LogicalResult LLVMFuncOp::verifyRegions() {
  if (isExternal())
    return success();

  unsigned numArguments = getFunctionType().getNumParams();
  Block &entryBlock = front();
  for (unsigned i = 0; i < numArguments; ++i) {
    Type argType = entryBlock.getArgument(i).getType();
    if (!isCompatibleType(argType))
      return emitOpError("entry block argument #")
             << i << " is not of LLVM type";
  }

  return success();
}

Region *LLVMFuncOp::getCallableRegion() {
  if (isExternal())
    return nullptr;
  return &getBody();
}

//===----------------------------------------------------------------------===//
// UndefOp.
//===----------------------------------------------------------------------===//

/// Fold an undef operation to a dedicated undef attribute.
OpFoldResult LLVM::UndefOp::fold(FoldAdaptor) {
  return LLVM::UndefAttr::get(getContext());
}

//===----------------------------------------------------------------------===//
// PoisonOp.
//===----------------------------------------------------------------------===//

/// Fold a poison operation to a dedicated poison attribute.
OpFoldResult LLVM::PoisonOp::fold(FoldAdaptor) {
  return LLVM::PoisonAttr::get(getContext());
}

//===----------------------------------------------------------------------===//
// ZeroOp.
//===----------------------------------------------------------------------===//

LogicalResult LLVM::ZeroOp::verify() {
  if (auto targetExtType = dyn_cast<LLVMTargetExtType>(getType()))
    if (!targetExtType.hasProperty(LLVM::LLVMTargetExtType::HasZeroInit))
      return emitOpError()
             << "target extension type does not support zero-initializer";

  return success();
}

/// Fold a zero operation to a builtin zero attribute when possible and fall
/// back to a dedicated zero attribute.
OpFoldResult LLVM::ZeroOp::fold(FoldAdaptor) {
  OpFoldResult result = Builder(getContext()).getZeroAttr(getType());
  if (result)
    return result;
  return LLVM::ZeroAttr::get(getContext());
}

//===----------------------------------------------------------------------===//
// ConstantOp.
//===----------------------------------------------------------------------===//

LogicalResult LLVM::ConstantOp::verify() {
  if (StringAttr sAttr = llvm::dyn_cast<StringAttr>(getValue())) {
    auto arrayType = llvm::dyn_cast<LLVMArrayType>(getType());
    if (!arrayType || arrayType.getNumElements() != sAttr.getValue().size() ||
        !arrayType.getElementType().isInteger(8)) {
      return emitOpError() << "expected array type of "
                           << sAttr.getValue().size()
                           << " i8 elements for the string constant";
    }
    return success();
  }
  if (auto structType = llvm::dyn_cast<LLVMStructType>(getType())) {
    if (structType.getBody().size() != 2 ||
        structType.getBody()[0] != structType.getBody()[1]) {
      return emitError() << "expected struct type with two elements of the "
                            "same type, the type of a complex constant";
    }

    auto arrayAttr = llvm::dyn_cast<ArrayAttr>(getValue());
    if (!arrayAttr || arrayAttr.size() != 2) {
      return emitOpError() << "expected array attribute with two elements, "
                              "representing a complex constant";
    }
    auto re = llvm::dyn_cast<TypedAttr>(arrayAttr[0]);
    auto im = llvm::dyn_cast<TypedAttr>(arrayAttr[1]);
    if (!re || !im || re.getType() != im.getType()) {
      return emitOpError()
             << "expected array attribute with two elements of the same type";
    }

    Type elementType = structType.getBody()[0];
    if (!llvm::isa<IntegerType, Float16Type, Float32Type, Float64Type>(
            elementType)) {
      return emitError()
             << "expected struct element types to be floating point type or "
                "integer type";
    }
    return success();
  }
  if (auto targetExtType = dyn_cast<LLVMTargetExtType>(getType())) {
    return emitOpError() << "does not support target extension type.";
  }
  if (!llvm::isa<IntegerAttr, ArrayAttr, FloatAttr, ElementsAttr>(getValue()))
    return emitOpError()
           << "only supports integer, float, string or elements attributes";
  if (auto intAttr = dyn_cast<IntegerAttr>(getValue())) {
    if (!llvm::isa<IntegerType>(getType()))
      return emitOpError() << "expected integer type";
  }
  if (auto floatAttr = dyn_cast<FloatAttr>(getValue())) {
    const llvm::fltSemantics &sem = floatAttr.getValue().getSemantics();
    unsigned floatWidth = APFloat::getSizeInBits(sem);
    if (auto floatTy = dyn_cast<FloatType>(getType())) {
      if (floatTy.getWidth() != floatWidth) {
        return emitOpError() << "expected float type of width " << floatWidth;
      }
    }
    // See the comment for getLLVMConstant for more details about why 8-bit
    // floats can be represented by integers.
    if (isa<IntegerType>(getType()) && !getType().isInteger(floatWidth)) {
      return emitOpError() << "expected integer type of width " << floatWidth;
    }
  }
  if (auto splatAttr = dyn_cast<SplatElementsAttr>(getValue())) {
    if (!isa<VectorType>(getType()) && !isa<LLVM::LLVMArrayType>(getType()) &&
        !isa<LLVM::LLVMFixedVectorType>(getType()) &&
        !isa<LLVM::LLVMScalableVectorType>(getType()))
      return emitOpError() << "expected vector or array type";
  }
  return success();
}

bool LLVM::ConstantOp::isBuildableWith(Attribute value, Type type) {
  // The value's type must be the same as the provided type.
  auto typedAttr = dyn_cast<TypedAttr>(value);
  if (!typedAttr || typedAttr.getType() != type || !isCompatibleType(type))
    return false;
  // The value's type must be an LLVM compatible type.
  if (!isCompatibleType(type))
    return false;
  // TODO: Add support for additional attributes kinds once needed.
  return isa<IntegerAttr, FloatAttr, ElementsAttr>(value);
}

ConstantOp LLVM::ConstantOp::materialize(OpBuilder &builder, Attribute value,
                                         Type type, Location loc) {
  if (isBuildableWith(value, type))
    return builder.create<LLVM::ConstantOp>(loc, cast<TypedAttr>(value));
  return nullptr;
}

// Constant op constant-folds to its value.
OpFoldResult LLVM::ConstantOp::fold(FoldAdaptor) { return getValue(); }

//===----------------------------------------------------------------------===//
// AtomicRMWOp
//===----------------------------------------------------------------------===//

void AtomicRMWOp::build(OpBuilder &builder, OperationState &state,
                        AtomicBinOp binOp, Value ptr, Value val,
                        AtomicOrdering ordering, StringRef syncscope,
                        unsigned alignment, bool isVolatile) {
  build(builder, state, val.getType(), binOp, ptr, val, ordering,
        !syncscope.empty() ? builder.getStringAttr(syncscope) : nullptr,
        alignment ? builder.getI64IntegerAttr(alignment) : nullptr, isVolatile,
        /*access_groups=*/nullptr,
        /*alias_scopes=*/nullptr, /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);
}

LogicalResult AtomicRMWOp::verify() {
  auto valType = getVal().getType();
  if (getBinOp() == AtomicBinOp::fadd || getBinOp() == AtomicBinOp::fsub ||
      getBinOp() == AtomicBinOp::fmin || getBinOp() == AtomicBinOp::fmax) {
    if (!mlir::LLVM::isCompatibleFloatingPointType(valType))
      return emitOpError("expected LLVM IR floating point type");
  } else if (getBinOp() == AtomicBinOp::xchg) {
    DataLayout dataLayout = DataLayout::closest(*this);
    if (!isTypeCompatibleWithAtomicOp(valType, dataLayout))
      return emitOpError("unexpected LLVM IR type for 'xchg' bin_op");
  } else {
    auto intType = llvm::dyn_cast<IntegerType>(valType);
    unsigned intBitWidth = intType ? intType.getWidth() : 0;
    if (intBitWidth != 8 && intBitWidth != 16 && intBitWidth != 32 &&
        intBitWidth != 64)
      return emitOpError("expected LLVM IR integer type");
  }

  if (static_cast<unsigned>(getOrdering()) <
      static_cast<unsigned>(AtomicOrdering::monotonic))
    return emitOpError() << "expected at least '"
                         << stringifyAtomicOrdering(AtomicOrdering::monotonic)
                         << "' ordering";

  return success();
}

//===----------------------------------------------------------------------===//
// AtomicCmpXchgOp
//===----------------------------------------------------------------------===//

/// Returns an LLVM struct type that contains a value type and a boolean type.
static LLVMStructType getValAndBoolStructType(Type valType) {
  auto boolType = IntegerType::get(valType.getContext(), 1);
  return LLVMStructType::getLiteral(valType.getContext(), {valType, boolType});
}

void AtomicCmpXchgOp::build(OpBuilder &builder, OperationState &state,
                            Value ptr, Value cmp, Value val,
                            AtomicOrdering successOrdering,
                            AtomicOrdering failureOrdering, StringRef syncscope,
                            unsigned alignment, bool isWeak, bool isVolatile) {
  build(builder, state, getValAndBoolStructType(val.getType()), ptr, cmp, val,
        successOrdering, failureOrdering,
        !syncscope.empty() ? builder.getStringAttr(syncscope) : nullptr,
        alignment ? builder.getI64IntegerAttr(alignment) : nullptr, isWeak,
        isVolatile, /*access_groups=*/nullptr,
        /*alias_scopes=*/nullptr, /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);
}

LogicalResult AtomicCmpXchgOp::verify() {
  auto ptrType = llvm::cast<LLVM::LLVMPointerType>(getPtr().getType());
  if (!ptrType)
    return emitOpError("expected LLVM IR pointer type for operand #0");
  auto valType = getVal().getType();
  DataLayout dataLayout = DataLayout::closest(*this);
  if (!isTypeCompatibleWithAtomicOp(valType, dataLayout))
    return emitOpError("unexpected LLVM IR type");
  if (getSuccessOrdering() < AtomicOrdering::monotonic ||
      getFailureOrdering() < AtomicOrdering::monotonic)
    return emitOpError("ordering must be at least 'monotonic'");
  if (getFailureOrdering() == AtomicOrdering::release ||
      getFailureOrdering() == AtomicOrdering::acq_rel)
    return emitOpError("failure ordering cannot be 'release' or 'acq_rel'");
  return success();
}

//===----------------------------------------------------------------------===//
// FenceOp
//===----------------------------------------------------------------------===//

void FenceOp::build(OpBuilder &builder, OperationState &state,
                    AtomicOrdering ordering, StringRef syncscope) {
  build(builder, state, ordering,
        syncscope.empty() ? nullptr : builder.getStringAttr(syncscope));
}

LogicalResult FenceOp::verify() {
  if (getOrdering() == AtomicOrdering::not_atomic ||
      getOrdering() == AtomicOrdering::unordered ||
      getOrdering() == AtomicOrdering::monotonic)
    return emitOpError("can be given only acquire, release, acq_rel, "
                       "and seq_cst orderings");
  return success();
}

//===----------------------------------------------------------------------===//
// Verifier for extension ops
//===----------------------------------------------------------------------===//

/// Verifies that the given extension operation operates on consistent scalars
/// or vectors, and that the target width is larger than the input width.
template <class ExtOp>
static LogicalResult verifyExtOp(ExtOp op) {
  IntegerType inputType, outputType;
  if (isCompatibleVectorType(op.getArg().getType())) {
    if (!isCompatibleVectorType(op.getResult().getType()))
      return op.emitError(
          "input type is a vector but output type is an integer");
    if (getVectorNumElements(op.getArg().getType()) !=
        getVectorNumElements(op.getResult().getType()))
      return op.emitError("input and output vectors are of incompatible shape");
    // Because this is a CastOp, the element of vectors is guaranteed to be an
    // integer.
    inputType = cast<IntegerType>(getVectorElementType(op.getArg().getType()));
    outputType =
        cast<IntegerType>(getVectorElementType(op.getResult().getType()));
  } else {
    // Because this is a CastOp and arg is not a vector, arg is guaranteed to be
    // an integer.
    inputType = cast<IntegerType>(op.getArg().getType());
    outputType = dyn_cast<IntegerType>(op.getResult().getType());
    if (!outputType)
      return op.emitError(
          "input type is an integer but output type is a vector");
  }

  if (outputType.getWidth() <= inputType.getWidth())
    return op.emitError("integer width of the output type is smaller or "
                        "equal to the integer width of the input type");
  return success();
}

//===----------------------------------------------------------------------===//
// ZExtOp
//===----------------------------------------------------------------------===//

LogicalResult ZExtOp::verify() { return verifyExtOp<ZExtOp>(*this); }

OpFoldResult LLVM::ZExtOp::fold(FoldAdaptor adaptor) {
  auto arg = dyn_cast_or_null<IntegerAttr>(adaptor.getArg());
  if (!arg)
    return {};

  size_t targetSize = cast<IntegerType>(getType()).getWidth();
  return IntegerAttr::get(getType(), arg.getValue().zext(targetSize));
}

//===----------------------------------------------------------------------===//
// SExtOp
//===----------------------------------------------------------------------===//

LogicalResult SExtOp::verify() { return verifyExtOp<SExtOp>(*this); }

//===----------------------------------------------------------------------===//
// Folder and verifier for LLVM::BitcastOp
//===----------------------------------------------------------------------===//

/// Folds a cast op that can be chained.
template <typename T>
static OpFoldResult foldChainableCast(T castOp,
                                      typename T::FoldAdaptor adaptor) {
  // cast(x : T0, T0) -> x
  if (castOp.getArg().getType() == castOp.getType())
    return castOp.getArg();
  if (auto prev = castOp.getArg().template getDefiningOp<T>()) {
    // cast(cast(x : T0, T1), T0) -> x
    if (prev.getArg().getType() == castOp.getType())
      return prev.getArg();
    // cast(cast(x : T0, T1), T2) -> cast(x: T0, T2)
    castOp.getArgMutable().set(prev.getArg());
    return Value{castOp};
  }
  return {};
}

OpFoldResult LLVM::BitcastOp::fold(FoldAdaptor adaptor) {
  return foldChainableCast(*this, adaptor);
}

LogicalResult LLVM::BitcastOp::verify() {
  auto resultType = llvm::dyn_cast<LLVMPointerType>(
      extractVectorElementType(getResult().getType()));
  auto sourceType = llvm::dyn_cast<LLVMPointerType>(
      extractVectorElementType(getArg().getType()));

  // If one of the types is a pointer (or vector of pointers), then
  // both source and result type have to be pointers.
  if (static_cast<bool>(resultType) != static_cast<bool>(sourceType))
    return emitOpError("can only cast pointers from and to pointers");

  if (!resultType)
    return success();

  auto isVector =
      llvm::IsaPred<VectorType, LLVMScalableVectorType, LLVMFixedVectorType>;

  // Due to bitcast requiring both operands to be of the same size, it is not
  // possible for only one of the two to be a pointer of vectors.
  if (isVector(getResult().getType()) && !isVector(getArg().getType()))
    return emitOpError("cannot cast pointer to vector of pointers");

  if (!isVector(getResult().getType()) && isVector(getArg().getType()))
    return emitOpError("cannot cast vector of pointers to pointer");

  // Bitcast cannot cast between pointers of different address spaces.
  // 'llvm.addrspacecast' must be used for this purpose instead.
  if (resultType.getAddressSpace() != sourceType.getAddressSpace())
    return emitOpError("cannot cast pointers of different address spaces, "
                       "use 'llvm.addrspacecast' instead");

  return success();
}

//===----------------------------------------------------------------------===//
// Folder for LLVM::AddrSpaceCastOp
//===----------------------------------------------------------------------===//

OpFoldResult LLVM::AddrSpaceCastOp::fold(FoldAdaptor adaptor) {
  return foldChainableCast(*this, adaptor);
}

//===----------------------------------------------------------------------===//
// Folder for LLVM::GEPOp
//===----------------------------------------------------------------------===//

OpFoldResult LLVM::GEPOp::fold(FoldAdaptor adaptor) {
  GEPIndicesAdaptor<ArrayRef<Attribute>> indices(getRawConstantIndicesAttr(),
                                                 adaptor.getDynamicIndices());

  // gep %x:T, 0 -> %x
  if (getBase().getType() == getType() && indices.size() == 1)
    if (auto integer = llvm::dyn_cast_or_null<IntegerAttr>(indices[0]))
      if (integer.getValue().isZero())
        return getBase();

  // Canonicalize any dynamic indices of constant value to constant indices.
  bool changed = false;
  SmallVector<GEPArg> gepArgs;
  for (auto iter : llvm::enumerate(indices)) {
    auto integer = llvm::dyn_cast_or_null<IntegerAttr>(iter.value());
    // Constant indices can only be int32_t, so if integer does not fit we
    // are forced to keep it dynamic, despite being a constant.
    if (!indices.isDynamicIndex(iter.index()) || !integer ||
        !integer.getValue().isSignedIntN(kGEPConstantBitWidth)) {

      PointerUnion<IntegerAttr, Value> existing = getIndices()[iter.index()];
      if (Value val = llvm::dyn_cast_if_present<Value>(existing))
        gepArgs.emplace_back(val);
      else
        gepArgs.emplace_back(existing.get<IntegerAttr>().getInt());

      continue;
    }

    changed = true;
    gepArgs.emplace_back(integer.getInt());
  }
  if (changed) {
    SmallVector<int32_t> rawConstantIndices;
    SmallVector<Value> dynamicIndices;
    destructureIndices(getElemType(), gepArgs, rawConstantIndices,
                       dynamicIndices);

    getDynamicIndicesMutable().assign(dynamicIndices);
    setRawConstantIndices(rawConstantIndices);
    return Value{*this};
  }

  return {};
}

//===----------------------------------------------------------------------===//
// ShlOp
//===----------------------------------------------------------------------===//

OpFoldResult LLVM::ShlOp::fold(FoldAdaptor adaptor) {
  auto rhs = dyn_cast_or_null<IntegerAttr>(adaptor.getRhs());
  if (!rhs)
    return {};

  if (rhs.getValue().getZExtValue() >=
      getLhs().getType().getIntOrFloatBitWidth())
    return {}; // TODO: Fold into poison.

  auto lhs = dyn_cast_or_null<IntegerAttr>(adaptor.getLhs());
  if (!lhs)
    return {};

  return IntegerAttr::get(getType(), lhs.getValue().shl(rhs.getValue()));
}

//===----------------------------------------------------------------------===//
// OrOp
//===----------------------------------------------------------------------===//

OpFoldResult LLVM::OrOp::fold(FoldAdaptor adaptor) {
  auto lhs = dyn_cast_or_null<IntegerAttr>(adaptor.getLhs());
  if (!lhs)
    return {};

  auto rhs = dyn_cast_or_null<IntegerAttr>(adaptor.getRhs());
  if (!rhs)
    return {};

  return IntegerAttr::get(getType(), lhs.getValue() | rhs.getValue());
}

//===----------------------------------------------------------------------===//
// CallIntrinsicOp
//===----------------------------------------------------------------------===//

LogicalResult CallIntrinsicOp::verify() {
  if (!getIntrin().starts_with("llvm."))
    return emitOpError() << "intrinsic name must start with 'llvm.'";
  return success();
}

//===----------------------------------------------------------------------===//
// OpAsmDialectInterface
//===----------------------------------------------------------------------===//

namespace {
struct LLVMOpAsmDialectInterface : public OpAsmDialectInterface {
  using OpAsmDialectInterface::OpAsmDialectInterface;

  AliasResult getAlias(Attribute attr, raw_ostream &os) const override {
    return TypeSwitch<Attribute, AliasResult>(attr)
        .Case<AccessGroupAttr, AliasScopeAttr, AliasScopeDomainAttr,
              DIBasicTypeAttr, DICompileUnitAttr, DICompositeTypeAttr,
              DIDerivedTypeAttr, DIFileAttr, DIGlobalVariableAttr,
              DIGlobalVariableExpressionAttr, DILabelAttr, DILexicalBlockAttr,
              DILexicalBlockFileAttr, DILocalVariableAttr, DIModuleAttr,
              DINamespaceAttr, DINullTypeAttr, DIStringTypeAttr,
              DISubprogramAttr, DISubroutineTypeAttr, LoopAnnotationAttr,
              LoopVectorizeAttr, LoopInterleaveAttr, LoopUnrollAttr,
              LoopUnrollAndJamAttr, LoopLICMAttr, LoopDistributeAttr,
              LoopPipelineAttr, LoopPeeledAttr, LoopUnswitchAttr, TBAARootAttr,
              TBAATagAttr, TBAATypeDescriptorAttr>([&](auto attr) {
          os << decltype(attr)::getMnemonic();
          return AliasResult::OverridableAlias;
        })
        .Default([](Attribute) { return AliasResult::NoAlias; });
  }
};
} // namespace

//===----------------------------------------------------------------------===//
// LinkerOptionsOp
//===----------------------------------------------------------------------===//

LogicalResult LinkerOptionsOp::verify() {
  if (mlir::Operation *parentOp = (*this)->getParentOp();
      parentOp && !satisfiesLLVMModule(parentOp))
    return emitOpError("must appear at the module level");
  return success();
}

//===----------------------------------------------------------------------===//
// InlineAsmOp
//===----------------------------------------------------------------------===//

void InlineAsmOp::getEffects(
    SmallVectorImpl<SideEffects::EffectInstance<MemoryEffects::Effect>>
        &effects) {
  if (getHasSideEffects()) {
    effects.emplace_back(MemoryEffects::Write::get());
    effects.emplace_back(MemoryEffects::Read::get());
  }
}

//===----------------------------------------------------------------------===//
// LLVMDialect initialization, type parsing, and registration.
//===----------------------------------------------------------------------===//

void LLVMDialect::initialize() {
  registerAttributes();

  // clang-format off
  addTypes<LLVMVoidType,
           LLVMPPCFP128Type,
           LLVMX86MMXType,
           LLVMTokenType,
           LLVMLabelType,
           LLVMMetadataType,
           LLVMStructType>();
  // clang-format on
  registerTypes();

  addOperations<
#define GET_OP_LIST
#include "mlir/Dialect/LLVMIR/LLVMOps.cpp.inc"
      ,
#define GET_OP_LIST
#include "mlir/Dialect/LLVMIR/LLVMIntrinsicOps.cpp.inc"
      >();

  // Support unknown operations because not all LLVM operations are registered.
  allowUnknownOperations();
  // clang-format off
  addInterfaces<LLVMOpAsmDialectInterface>();
  // clang-format on
  detail::addLLVMInlinerInterface(this);
}

#define GET_OP_CLASSES
#include "mlir/Dialect/LLVMIR/LLVMOps.cpp.inc"

#define GET_OP_CLASSES
#include "mlir/Dialect/LLVMIR/LLVMIntrinsicOps.cpp.inc"

LogicalResult LLVMDialect::verifyDataLayoutString(
    StringRef descr, llvm::function_ref<void(const Twine &)> reportError) {
  llvm::Expected<llvm::DataLayout> maybeDataLayout =
      llvm::DataLayout::parse(descr);
  if (maybeDataLayout)
    return success();

  std::string message;
  llvm::raw_string_ostream messageStream(message);
  llvm::logAllUnhandledErrors(maybeDataLayout.takeError(), messageStream);
  reportError("invalid data layout descriptor: " + messageStream.str());
  return failure();
}

/// Verify LLVM dialect attributes.
LogicalResult LLVMDialect::verifyOperationAttribute(Operation *op,
                                                    NamedAttribute attr) {
  // If the data layout attribute is present, it must use the LLVM data layout
  // syntax. Try parsing it and report errors in case of failure. Users of this
  // attribute may assume it is well-formed and can pass it to the (asserting)
  // llvm::DataLayout constructor.
  if (attr.getName() != LLVM::LLVMDialect::getDataLayoutAttrName())
    return success();
  if (auto stringAttr = llvm::dyn_cast<StringAttr>(attr.getValue()))
    return verifyDataLayoutString(
        stringAttr.getValue(),
        [op](const Twine &message) { op->emitOpError() << message.str(); });

  return op->emitOpError() << "expected '"
                           << LLVM::LLVMDialect::getDataLayoutAttrName()
                           << "' to be a string attributes";
}

LogicalResult LLVMDialect::verifyParameterAttribute(Operation *op,
                                                    Type paramType,
                                                    NamedAttribute paramAttr) {
  // LLVM attribute may be attached to a result of operation that has not been
  // converted to LLVM dialect yet, so the result may have a type with unknown
  // representation in LLVM dialect type space. In this case we cannot verify
  // whether the attribute may be
  bool verifyValueType = isCompatibleType(paramType);
  StringAttr name = paramAttr.getName();

  auto checkUnitAttrType = [&]() -> LogicalResult {
    if (!llvm::isa<UnitAttr>(paramAttr.getValue()))
      return op->emitError() << name << " should be a unit attribute";
    return success();
  };
  auto checkTypeAttrType = [&]() -> LogicalResult {
    if (!llvm::isa<TypeAttr>(paramAttr.getValue()))
      return op->emitError() << name << " should be a type attribute";
    return success();
  };
  auto checkIntegerAttrType = [&]() -> LogicalResult {
    if (!llvm::isa<IntegerAttr>(paramAttr.getValue()))
      return op->emitError() << name << " should be an integer attribute";
    return success();
  };
  auto checkPointerType = [&]() -> LogicalResult {
    if (!llvm::isa<LLVMPointerType>(paramType))
      return op->emitError()
             << name << " attribute attached to non-pointer LLVM type";
    return success();
  };
  auto checkIntegerType = [&]() -> LogicalResult {
    if (!llvm::isa<IntegerType>(paramType))
      return op->emitError()
             << name << " attribute attached to non-integer LLVM type";
    return success();
  };
  auto checkPointerTypeMatches = [&]() -> LogicalResult {
    if (failed(checkPointerType()))
      return failure();

    return success();
  };

  // Check a unit attribute that is attached to a pointer value.
  if (name == LLVMDialect::getNoAliasAttrName() ||
      name == LLVMDialect::getReadonlyAttrName() ||
      name == LLVMDialect::getReadnoneAttrName() ||
      name == LLVMDialect::getWriteOnlyAttrName() ||
      name == LLVMDialect::getNestAttrName() ||
      name == LLVMDialect::getNoCaptureAttrName() ||
      name == LLVMDialect::getNoFreeAttrName() ||
      name == LLVMDialect::getNonNullAttrName()) {
    if (failed(checkUnitAttrType()))
      return failure();
    if (verifyValueType && failed(checkPointerType()))
      return failure();
    return success();
  }

  // Check a type attribute that is attached to a pointer value.
  if (name == LLVMDialect::getStructRetAttrName() ||
      name == LLVMDialect::getByValAttrName() ||
      name == LLVMDialect::getByRefAttrName() ||
      name == LLVMDialect::getInAllocaAttrName() ||
      name == LLVMDialect::getPreallocatedAttrName()) {
    if (failed(checkTypeAttrType()))
      return failure();
    if (verifyValueType && failed(checkPointerTypeMatches()))
      return failure();
    return success();
  }

  // Check a unit attribute that is attached to an integer value.
  if (name == LLVMDialect::getSExtAttrName() ||
      name == LLVMDialect::getZExtAttrName()) {
    if (failed(checkUnitAttrType()))
      return failure();
    if (verifyValueType && failed(checkIntegerType()))
      return failure();
    return success();
  }

  // Check an integer attribute that is attached to a pointer value.
  if (name == LLVMDialect::getAlignAttrName() ||
      name == LLVMDialect::getDereferenceableAttrName() ||
      name == LLVMDialect::getDereferenceableOrNullAttrName() ||
      name == LLVMDialect::getStackAlignmentAttrName()) {
    if (failed(checkIntegerAttrType()))
      return failure();
    if (verifyValueType && failed(checkPointerType()))
      return failure();
    return success();
  }

  // Check a unit attribute that can be attached to arbitrary types.
  if (name == LLVMDialect::getNoUndefAttrName() ||
      name == LLVMDialect::getInRegAttrName() ||
      name == LLVMDialect::getReturnedAttrName())
    return checkUnitAttrType();

  return success();
}

/// Verify LLVMIR function argument attributes.
LogicalResult LLVMDialect::verifyRegionArgAttribute(Operation *op,
                                                    unsigned regionIdx,
                                                    unsigned argIdx,
                                                    NamedAttribute argAttr) {
  auto funcOp = dyn_cast<FunctionOpInterface>(op);
  if (!funcOp)
    return success();
  Type argType = funcOp.getArgumentTypes()[argIdx];

  return verifyParameterAttribute(op, argType, argAttr);
}

LogicalResult LLVMDialect::verifyRegionResultAttribute(Operation *op,
                                                       unsigned regionIdx,
                                                       unsigned resIdx,
                                                       NamedAttribute resAttr) {
  auto funcOp = dyn_cast<FunctionOpInterface>(op);
  if (!funcOp)
    return success();
  Type resType = funcOp.getResultTypes()[resIdx];

  // Check to see if this function has a void return with a result attribute
  // to it. It isn't clear what semantics we would assign to that.
  if (llvm::isa<LLVMVoidType>(resType))
    return op->emitError() << "cannot attach result attributes to functions "
                              "with a void return";

  // Check to see if this attribute is allowed as a result attribute. Only
  // explicitly forbidden LLVM attributes will cause an error.
  auto name = resAttr.getName();
  if (name == LLVMDialect::getAllocAlignAttrName() ||
      name == LLVMDialect::getAllocatedPointerAttrName() ||
      name == LLVMDialect::getByValAttrName() ||
      name == LLVMDialect::getByRefAttrName() ||
      name == LLVMDialect::getInAllocaAttrName() ||
      name == LLVMDialect::getNestAttrName() ||
      name == LLVMDialect::getNoCaptureAttrName() ||
      name == LLVMDialect::getNoFreeAttrName() ||
      name == LLVMDialect::getPreallocatedAttrName() ||
      name == LLVMDialect::getReadnoneAttrName() ||
      name == LLVMDialect::getReadonlyAttrName() ||
      name == LLVMDialect::getReturnedAttrName() ||
      name == LLVMDialect::getStackAlignmentAttrName() ||
      name == LLVMDialect::getStructRetAttrName() ||
      name == LLVMDialect::getWriteOnlyAttrName())
    return op->emitError() << name << " is not a valid result attribute";
  return verifyParameterAttribute(op, resType, resAttr);
}

Operation *LLVMDialect::materializeConstant(OpBuilder &builder, Attribute value,
                                            Type type, Location loc) {
  // If this was folded from an operation other than llvm.mlir.constant, it
  // should be materialized as such. Note that an llvm.mlir.zero may fold into
  // a builtin zero attribute and thus will materialize as a llvm.mlir.constant.
  if (auto symbol = dyn_cast<FlatSymbolRefAttr>(value))
    if (isa<LLVM::LLVMPointerType>(type))
      return builder.create<LLVM::AddressOfOp>(loc, type, symbol);
  if (isa<LLVM::UndefAttr>(value))
    return builder.create<LLVM::UndefOp>(loc, type);
  if (isa<LLVM::PoisonAttr>(value))
    return builder.create<LLVM::PoisonOp>(loc, type);
  if (isa<LLVM::ZeroAttr>(value))
    return builder.create<LLVM::ZeroOp>(loc, type);
  // Otherwise try materializing it as a regular llvm.mlir.constant op.
  return LLVM::ConstantOp::materialize(builder, value, type, loc);
}

//===----------------------------------------------------------------------===//
// Utility functions.
//===----------------------------------------------------------------------===//

Value mlir::LLVM::createGlobalString(Location loc, OpBuilder &builder,
                                     StringRef name, StringRef value,
                                     LLVM::Linkage linkage) {
  assert(builder.getInsertionBlock() &&
         builder.getInsertionBlock()->getParentOp() &&
         "expected builder to point to a block constrained in an op");
  auto module =
      builder.getInsertionBlock()->getParentOp()->getParentOfType<ModuleOp>();
  assert(module && "builder points to an op outside of a module");

  // Create the global at the entry of the module.
  OpBuilder moduleBuilder(module.getBodyRegion(), builder.getListener());
  MLIRContext *ctx = builder.getContext();
  auto type = LLVM::LLVMArrayType::get(IntegerType::get(ctx, 8), value.size());
  auto global = moduleBuilder.create<LLVM::GlobalOp>(
      loc, type, /*isConstant=*/true, linkage, name,
      builder.getStringAttr(value), /*alignment=*/0);

  LLVMPointerType ptrType = LLVMPointerType::get(ctx);
  // Get the pointer to the first character in the global string.
  Value globalPtr =
      builder.create<LLVM::AddressOfOp>(loc, ptrType, global.getSymNameAttr());
  return builder.create<LLVM::GEPOp>(loc, ptrType, type, globalPtr,
                                     ArrayRef<GEPArg>{0, 0});
}

bool mlir::LLVM::satisfiesLLVMModule(Operation *op) {
  return op->hasTrait<OpTrait::SymbolTable>() &&
         op->hasTrait<OpTrait::IsIsolatedFromAbove>();
}