CIRGenBuilder.h

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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CLANG_LIB_CIR_CODEGEN_CIRGENBUILDER_H
#define LLVM_CLANG_LIB_CIR_CODEGEN_CIRGENBUILDER_H
 
#include "Address.h"
#include "CIRGenRecordLayout.h"
#include "CIRGenTypeCache.h"
#include "mlir/IR/Attributes.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/Support/LLVM.h"
#include "clang/CIR/Dialect/IR/CIRDataLayout.h"
#include "clang/CIR/MissingFeatures.h"
 
#include "clang/CIR/Dialect/Builder/CIRBaseBuilder.h"
#include "clang/CIR/MissingFeatures.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/STLExtras.h"
 
namespace clang::CIRGen {
 
class CIRGenBuilderTy : public cir::CIRBaseBuilderTy {
  const CIRGenTypeCache &typeCache;
  llvm::StringMap<unsigned> recordNames;
  llvm::StringMap<unsigned> globalsVersioning;
 
public:
  CIRGenBuilderTy(mlir::MLIRContext &mlirContext, const CIRGenTypeCache &tc)
      : CIRBaseBuilderTy(mlirContext), typeCache(tc) {}
 
  /// Get a cir::ConstArrayAttr for a string literal.
  /// Note: This is different from what is returned by
  /// mlir::Builder::getStringAttr() which is an mlir::StringAttr.
  mlir::Attribute getString(llvm::StringRef str, mlir::Type eltTy,
                            std::optional<size_t> size) {
    size_t finalSize = size.value_or(str.size());
 
    size_t lastNonZeroPos = str.find_last_not_of('\0');
    // If the string is full of null bytes, emit a #cir.zero rather than
    // a #cir.const_array.
    if (lastNonZeroPos == llvm::StringRef::npos) {
      auto arrayTy = cir::ArrayType::get(eltTy, finalSize);
      return cir::ZeroAttr::get(arrayTy);
    }
    // We emit trailing zeros only if there are multiple trailing zeros.
    size_t trailingZerosNum = 0;
    if (finalSize > lastNonZeroPos + 2)
      trailingZerosNum = finalSize - lastNonZeroPos - 1;
    auto truncatedArrayTy =
        cir::ArrayType::get(eltTy, finalSize - trailingZerosNum);
    auto fullArrayTy = cir::ArrayType::get(eltTy, finalSize);
    return cir::ConstArrayAttr::get(
        fullArrayTy,
        mlir::StringAttr::get(str.drop_back(trailingZerosNum),
                              truncatedArrayTy),
        trailingZerosNum);
  }
 
  cir::ConstArrayAttr getConstArray(mlir::Attribute attrs,
                                    cir::ArrayType arrayTy) const {
    return cir::ConstArrayAttr::get(arrayTy, attrs);
  }
 
  mlir::Attribute getConstRecordOrZeroAttr(mlir::ArrayAttr arrayAttr,
                                           bool packed = false,
                                           bool padded = false,
                                           mlir::Type type = {});
 
  cir::ConstRecordAttr getAnonConstRecord(mlir::ArrayAttr arrayAttr,
                                          bool packed = false,
                                          bool padded = false,
                                          mlir::Type ty = {}) {
    llvm::SmallVector<mlir::Type, 4> members;
    for (auto &f : arrayAttr) {
      auto ta = mlir::cast<mlir::TypedAttr>(f);
      members.push_back(ta.getType());
    }
 
    if (!ty)
      ty = getAnonRecordTy(members, packed, padded);
 
    auto sTy = mlir::cast<cir::RecordType>(ty);
    return cir::ConstRecordAttr::get(sTy, arrayAttr);
  }
 
  cir::TypeInfoAttr getTypeInfo(mlir::ArrayAttr fieldsAttr) {
    cir::ConstRecordAttr anonRecord = getAnonConstRecord(fieldsAttr);
    return cir::TypeInfoAttr::get(anonRecord.getType(), fieldsAttr);
  }
 
  std::string getUniqueAnonRecordName() { return getUniqueRecordName("anon"); }
 
  std::string getUniqueRecordName(const std::string &baseName) {
    auto it = recordNames.find(baseName);
    if (it == recordNames.end()) {
      recordNames[baseName] = 0;
      return baseName;
    }
 
    return baseName + "." + std::to_string(recordNames[baseName]++);
  }
 
  cir::LongDoubleType getLongDoubleTy(const llvm::fltSemantics &format) const {
    if (&format == &llvm::APFloat::IEEEdouble())
      return cir::LongDoubleType::get(getContext(), typeCache.DoubleTy);
    if (&format == &llvm::APFloat::x87DoubleExtended())
      return cir::LongDoubleType::get(getContext(), typeCache.FP80Ty);
    if (&format == &llvm::APFloat::IEEEquad())
      return cir::LongDoubleType::get(getContext(), typeCache.FP128Ty);
    if (&format == &llvm::APFloat::PPCDoubleDouble())
      llvm_unreachable("NYI: PPC double-double format for long double");
    llvm_unreachable("Unsupported format for long double");
  }
 
  mlir::Type getPtrToVPtrType() {
    return getPointerTo(cir::VPtrType::get(getContext()));
  }
 
  /// Get a CIR record kind from a AST declaration tag.
  cir::RecordType::RecordKind getRecordKind(const clang::TagTypeKind kind) {
    switch (kind) {
    case clang::TagTypeKind::Class:
      return cir::RecordType::Class;
    case clang::TagTypeKind::Struct:
      return cir::RecordType::Struct;
    case clang::TagTypeKind::Union:
      return cir::RecordType::Union;
    case clang::TagTypeKind::Interface:
      llvm_unreachable("interface records are NYI");
    case clang::TagTypeKind::Enum:
      llvm_unreachable("enums are not records");
    }
    llvm_unreachable("Unsupported record kind");
  }
 
  /// Get a CIR named record type.
  ///
  /// If a record already exists and is complete, but the client tries to fetch
  /// it with a different set of attributes, this method will crash.
  cir::RecordType getCompleteNamedRecordType(llvm::ArrayRef<mlir::Type> members,
                                             bool packed, bool padded,
                                             llvm::StringRef name) {
    const auto nameAttr = getStringAttr(name);
    auto kind = cir::RecordType::RecordKind::Struct;
    assert(!cir::MissingFeatures::astRecordDeclAttr());
 
    // Create or get the record.
    auto type =
        getType<cir::RecordType>(members, nameAttr, packed, padded, kind);
 
    // If we found an existing type, verify that either it is incomplete or
    // it matches the requested attributes.
    assert(!type.isIncomplete() ||
           (type.getMembers() == members && type.getPacked() == packed &&
            type.getPadded() == padded));
 
    // Complete an incomplete record or ensure the existing complete record
    // matches the requested attributes.
    type.complete(members, packed, padded);
 
    return type;
  }
 
  cir::RecordType getCompleteRecordType(mlir::ArrayAttr fields,
                                        bool packed = false,
                                        bool padded = false,
                                        llvm::StringRef name = "");
 
  /// Get an incomplete CIR struct type. If we have a complete record
  /// declaration, we may create an incomplete type and then add the
  /// members, so \p rd here may be complete.
  cir::RecordType getIncompleteRecordTy(llvm::StringRef name,
                                        const clang::RecordDecl *rd) {
    const mlir::StringAttr nameAttr = getStringAttr(name);
    cir::RecordType::RecordKind kind = cir::RecordType::RecordKind::Struct;
    if (rd)
      kind = getRecordKind(rd->getTagKind());
    return getType<cir::RecordType>(nameAttr, kind);
  }
 
  // Return true if the value is a null constant such as null pointer, (+0.0)
  // for floating-point or zero initializer
  bool isNullValue(mlir::Attribute attr) const {
    if (mlir::isa<cir::ZeroAttr>(attr))
      return true;
 
    if (const auto ptrVal = mlir::dyn_cast<cir::ConstPtrAttr>(attr))
      return ptrVal.isNullValue();
 
    if (const auto intVal = mlir::dyn_cast<cir::IntAttr>(attr))
      return intVal.isNullValue();
 
    if (const auto boolVal = mlir::dyn_cast<cir::BoolAttr>(attr))
      return !boolVal.getValue();
 
    if (auto fpAttr = mlir::dyn_cast<cir::FPAttr>(attr)) {
      auto fpVal = fpAttr.getValue();
      bool ignored;
      llvm::APFloat fv(+0.0);
      fv.convert(fpVal.getSemantics(), llvm::APFloat::rmNearestTiesToEven,
                 &ignored);
      return fv.bitwiseIsEqual(fpVal);
    }
 
    if (const auto arrayVal = mlir::dyn_cast<cir::ConstArrayAttr>(attr)) {
      if (mlir::isa<mlir::StringAttr>(arrayVal.getElts()))
        return false;
 
      return llvm::all_of(
          mlir::cast<mlir::ArrayAttr>(arrayVal.getElts()),
          [&](const mlir::Attribute &elt) { return isNullValue(elt); });
    }
    return false;
  }
 
  //
  // Type helpers
  // ------------
  //
  cir::IntType getUIntNTy(int n) {
    switch (n) {
    case 8:
      return getUInt8Ty();
    case 16:
      return getUInt16Ty();
    case 32:
      return getUInt32Ty();
    case 64:
      return getUInt64Ty();
    default:
      return cir::IntType::get(getContext(), n, false);
    }
  }
 
  cir::IntType getSIntNTy(int n) {
    switch (n) {
    case 8:
      return getSInt8Ty();
    case 16:
      return getSInt16Ty();
    case 32:
      return getSInt32Ty();
    case 64:
      return getSInt64Ty();
    default:
      return cir::IntType::get(getContext(), n, true);
    }
  }
 
  cir::VoidType getVoidTy() { return typeCache.VoidTy; }
 
  cir::IntType getSInt8Ty() { return typeCache.SInt8Ty; }
  cir::IntType getSInt16Ty() { return typeCache.SInt16Ty; }
  cir::IntType getSInt32Ty() { return typeCache.SInt32Ty; }
  cir::IntType getSInt64Ty() { return typeCache.SInt64Ty; }
 
  cir::IntType getUInt8Ty() { return typeCache.UInt8Ty; }
  cir::IntType getUInt16Ty() { return typeCache.UInt16Ty; }
  cir::IntType getUInt32Ty() { return typeCache.UInt32Ty; }
  cir::IntType getUInt64Ty() { return typeCache.UInt64Ty; }
 
  cir::ConstantOp getConstInt(mlir::Location loc, llvm::APSInt intVal);
 
  cir::ConstantOp getConstInt(mlir::Location loc, llvm::APInt intVal);
 
  cir::ConstantOp getConstInt(mlir::Location loc, mlir::Type t, uint64_t c);
 
  cir::ConstantOp getConstFP(mlir::Location loc, mlir::Type t,
                             llvm::APFloat fpVal);
 
  bool isInt8Ty(mlir::Type i) {
    return i == typeCache.UInt8Ty || i == typeCache.SInt8Ty;
  }
  bool isInt16Ty(mlir::Type i) {
    return i == typeCache.UInt16Ty || i == typeCache.SInt16Ty;
  }
  bool isInt32Ty(mlir::Type i) {
    return i == typeCache.UInt32Ty || i == typeCache.SInt32Ty;
  }
  bool isInt64Ty(mlir::Type i) {
    return i == typeCache.UInt64Ty || i == typeCache.SInt64Ty;
  }
  bool isInt(mlir::Type i) { return mlir::isa<cir::IntType>(i); }
 
  // Fetch the type representing a pointer to unsigned int8 values.
  cir::PointerType getUInt8PtrTy() { return typeCache.UInt8PtrTy; }
 
  /// Get a CIR anonymous record type.
  cir::RecordType getAnonRecordTy(llvm::ArrayRef<mlir::Type> members,
                                  bool packed = false, bool padded = false) {
    assert(!cir::MissingFeatures::astRecordDeclAttr());
    auto kind = cir::RecordType::RecordKind::Struct;
    return getType<cir::RecordType>(members, packed, padded, kind);
  }
 
  //
  // Constant creation helpers
  // -------------------------
  //
  cir::ConstantOp getSInt32(int32_t c, mlir::Location loc) {
    return getConstantInt(loc, getSInt32Ty(), c);
  }
  cir::ConstantOp getUInt32(uint32_t c, mlir::Location loc) {
    return getConstantInt(loc, getUInt32Ty(), c);
  }
  cir::ConstantOp getSInt64(uint64_t c, mlir::Location loc) {
    cir::IntType sInt64Ty = getSInt64Ty();
    return cir::ConstantOp::create(*this, loc, cir::IntAttr::get(sInt64Ty, c));
  }
 
  // Creates constant nullptr for pointer type ty.
  cir::ConstantOp getNullPtr(mlir::Type ty, mlir::Location loc) {
    assert(!cir::MissingFeatures::targetCodeGenInfoGetNullPointer());
    return cir::ConstantOp::create(*this, loc, getConstPtrAttr(ty, 0));
  }
 
  mlir::Value createNeg(mlir::Value value) {
 
    if (auto intTy = mlir::dyn_cast<cir::IntType>(value.getType())) {
      // Source is a unsigned integer: first cast it to signed.
      if (intTy.isUnsigned())
        value = createIntCast(value, getSIntNTy(intTy.getWidth()));
      return cir::UnaryOp::create(*this, value.getLoc(), value.getType(),
                                  cir::UnaryOpKind::Minus, value);
    }
 
    llvm_unreachable("negation for the given type is NYI");
  }
 
  // TODO: split this to createFPExt/createFPTrunc when we have dedicated cast
  // operations.
  mlir::Value createFloatingCast(mlir::Value v, mlir::Type destType) {
    assert(!cir::MissingFeatures::fpConstraints());
 
    return cir::CastOp::create(*this, v.getLoc(), destType,
                               cir::CastKind::floating, v);
  }
 
  mlir::Value createFSub(mlir::Location loc, mlir::Value lhs, mlir::Value rhs) {
    assert(!cir::MissingFeatures::metaDataNode());
    assert(!cir::MissingFeatures::fpConstraints());
    assert(!cir::MissingFeatures::fastMathFlags());
 
    return cir::BinOp::create(*this, loc, cir::BinOpKind::Sub, lhs, rhs);
  }
 
  mlir::Value createFAdd(mlir::Location loc, mlir::Value lhs, mlir::Value rhs) {
    assert(!cir::MissingFeatures::metaDataNode());
    assert(!cir::MissingFeatures::fpConstraints());
    assert(!cir::MissingFeatures::fastMathFlags());
 
    return cir::BinOp::create(*this, loc, cir::BinOpKind::Add, lhs, rhs);
  }
  mlir::Value createFMul(mlir::Location loc, mlir::Value lhs, mlir::Value rhs) {
    assert(!cir::MissingFeatures::metaDataNode());
    assert(!cir::MissingFeatures::fpConstraints());
    assert(!cir::MissingFeatures::fastMathFlags());
 
    return cir::BinOp::create(*this, loc, cir::BinOpKind::Mul, lhs, rhs);
  }
  mlir::Value createFDiv(mlir::Location loc, mlir::Value lhs, mlir::Value rhs) {
    assert(!cir::MissingFeatures::metaDataNode());
    assert(!cir::MissingFeatures::fpConstraints());
    assert(!cir::MissingFeatures::fastMathFlags());
 
    return cir::BinOp::create(*this, loc, cir::BinOpKind::Div, lhs, rhs);
  }
 
  Address createBaseClassAddr(mlir::Location loc, Address addr,
                              mlir::Type destType, unsigned offset,
                              bool assumeNotNull) {
    if (destType == addr.getElementType())
      return addr;
 
    auto ptrTy = getPointerTo(destType);
    auto baseAddr =
        cir::BaseClassAddrOp::create(*this, loc, ptrTy, addr.getPointer(),
                                     mlir::APInt(64, offset), assumeNotNull);
    return Address(baseAddr, destType, addr.getAlignment());
  }
 
  mlir::Value createVTTAddrPoint(mlir::Location loc, mlir::Type retTy,
                                 mlir::Value addr, uint64_t offset) {
    return cir::VTTAddrPointOp::create(*this, loc, retTy,
                                       mlir::FlatSymbolRefAttr{}, addr, offset);
  }
 
  mlir::Value createVTTAddrPoint(mlir::Location loc, mlir::Type retTy,
                                 mlir::FlatSymbolRefAttr sym, uint64_t offset) {
    return cir::VTTAddrPointOp::create(*this, loc, retTy, sym, mlir::Value{},
                                       offset);
  }
 
  /// Cast the element type of the given address to a different type,
  /// preserving information like the alignment.
  Address createElementBitCast(mlir::Location loc, Address addr,
                               mlir::Type destType) {
    if (destType == addr.getElementType())
      return addr;
 
    auto ptrTy = getPointerTo(destType);
    return Address(createBitcast(loc, addr.getPointer(), ptrTy), destType,
                   addr.getAlignment());
  }
 
  cir::LoadOp createLoad(mlir::Location loc, Address addr,
                         bool isVolatile = false) {
    mlir::IntegerAttr align = getAlignmentAttr(addr.getAlignment());
    return cir::LoadOp::create(*this, loc, addr.getPointer(), /*isDeref=*/false,
                               isVolatile, /*alignment=*/align,
                               /*mem_order=*/cir::MemOrderAttr{});
  }
 
  cir::LoadOp createAlignedLoad(mlir::Location loc, mlir::Type ty,
                                mlir::Value ptr, llvm::MaybeAlign align) {
    if (ty != mlir::cast<cir::PointerType>(ptr.getType()).getPointee())
      ptr = createPtrBitcast(ptr, ty);
    uint64_t alignment = align ? align->value() : 0;
    mlir::IntegerAttr alignAttr = getAlignmentAttr(alignment);
    return cir::LoadOp::create(*this, loc, ptr, /*isDeref=*/false,
                               /*isVolatile=*/false, alignAttr,
                               /*mem_order=*/cir::MemOrderAttr{});
  }
 
  cir::LoadOp
  createAlignedLoad(mlir::Location loc, mlir::Type ty, mlir::Value ptr,
                    clang::CharUnits align = clang::CharUnits::One()) {
    return createAlignedLoad(loc, ty, ptr, align.getAsAlign());
  }
 
  cir::StoreOp createStore(mlir::Location loc, mlir::Value val, Address dst,
                           bool isVolatile = false,
                           mlir::IntegerAttr align = {},
                           cir::MemOrderAttr order = {}) {
    if (!align)
      align = getAlignmentAttr(dst.getAlignment());
    return CIRBaseBuilderTy::createStore(loc, val, dst.getPointer(), isVolatile,
                                         align, order);
  }
 
  /// Create a cir.complex.real_ptr operation that derives a pointer to the real
  /// part of the complex value pointed to by the specified pointer value.
  mlir::Value createComplexRealPtr(mlir::Location loc, mlir::Value value) {
    auto srcPtrTy = mlir::cast<cir::PointerType>(value.getType());
    auto srcComplexTy = mlir::cast<cir::ComplexType>(srcPtrTy.getPointee());
    return cir::ComplexRealPtrOp::create(
        *this, loc, getPointerTo(srcComplexTy.getElementType()), value);
  }
 
  Address createComplexRealPtr(mlir::Location loc, Address addr) {
    return Address{createComplexRealPtr(loc, addr.getPointer()),
                   addr.getAlignment()};
  }
 
  /// Create a cir.complex.imag_ptr operation that derives a pointer to the
  /// imaginary part of the complex value pointed to by the specified pointer
  /// value.
  mlir::Value createComplexImagPtr(mlir::Location loc, mlir::Value value) {
    auto srcPtrTy = mlir::cast<cir::PointerType>(value.getType());
    auto srcComplexTy = mlir::cast<cir::ComplexType>(srcPtrTy.getPointee());
    return cir::ComplexImagPtrOp::create(
        *this, loc, getPointerTo(srcComplexTy.getElementType()), value);
  }
 
  Address createComplexImagPtr(mlir::Location loc, Address addr) {
    return Address{createComplexImagPtr(loc, addr.getPointer()),
                   addr.getAlignment()};
  }
 
  /// Create a cir.ptr_stride operation to get access to an array element.
  /// \p idx is the index of the element to access, \p shouldDecay is true if
  /// the result should decay to a pointer to the element type.
  mlir::Value getArrayElement(mlir::Location arrayLocBegin,
                              mlir::Location arrayLocEnd, mlir::Value arrayPtr,
                              mlir::Type eltTy, mlir::Value idx,
                              bool shouldDecay);
 
  /// Returns a decayed pointer to the first element of the array
  /// pointed to by \p arrayPtr.
  mlir::Value maybeBuildArrayDecay(mlir::Location loc, mlir::Value arrayPtr,
                                   mlir::Type eltTy);
 
  // Convert byte offset to sequence of high-level indices suitable for
  // GlobalViewAttr. Ideally we shouldn't deal with low-level offsets at all
  // but currently some parts of Clang AST, which we don't want to touch just
  // yet, return them.
  void computeGlobalViewIndicesFromFlatOffset(
      int64_t offset, mlir::Type ty, cir::CIRDataLayout layout,
      llvm::SmallVectorImpl<int64_t> &indices);
 
  /// Creates a versioned global variable. If the symbol is already taken, an ID
  /// will be appended to the symbol. The returned global must always be queried
  /// for its name so it can be referenced correctly.
  [[nodiscard]] cir::GlobalOp
  createVersionedGlobal(mlir::ModuleOp module, mlir::Location loc,
                        mlir::StringRef name, mlir::Type type, bool isConstant,
                        cir::GlobalLinkageKind linkage) {
    // Create a unique name if the given name is already taken.
    std::string uniqueName;
    if (unsigned version = globalsVersioning[name.str()]++)
      uniqueName = name.str() + "." + std::to_string(version);
    else
      uniqueName = name.str();
 
    return createGlobal(module, loc, uniqueName, type, isConstant, linkage);
  }
 
  mlir::Value createSetBitfield(mlir::Location loc, mlir::Type resultType,
                                Address dstAddr, mlir::Type storageType,
                                mlir::Value src, const CIRGenBitFieldInfo &info,
                                bool isLvalueVolatile, bool useVolatile) {
    unsigned offset = useVolatile ? info.volatileOffset : info.offset;
 
    // If using AAPCS and the field is volatile, load with the size of the
    // declared field
    storageType =
        useVolatile ? cir::IntType::get(storageType.getContext(),
                                        info.volatileStorageSize, info.isSigned)
                    : storageType;
    return cir::SetBitfieldOp::create(
        *this, loc, resultType, dstAddr.getPointer(), storageType, src,
        info.name, info.size, offset, info.isSigned, isLvalueVolatile,
        dstAddr.getAlignment().getAsAlign().value());
  }
 
  mlir::Value createGetBitfield(mlir::Location loc, mlir::Type resultType,
                                Address addr, mlir::Type storageType,
                                const CIRGenBitFieldInfo &info,
                                bool isLvalueVolatile, bool useVolatile) {
    unsigned offset = useVolatile ? info.volatileOffset : info.offset;
 
    // If using AAPCS and the field is volatile, load with the size of the
    // declared field
    storageType =
        useVolatile ? cir::IntType::get(storageType.getContext(),
                                        info.volatileStorageSize, info.isSigned)
                    : storageType;
    return cir::GetBitfieldOp::create(*this, loc, resultType, addr.getPointer(),
                                      storageType, info.name, info.size, offset,
                                      info.isSigned, isLvalueVolatile,
                                      addr.getAlignment().getAsAlign().value());
  }
};
 
} // namespace clang::CIRGen
 
#endif