Function ComputeDataLayout

ThunkLibs/Generator/data_layout.cpp:24–154

  : type_abi(abi_) {}

std::unordered_map<const clang::Type*, TypeInfo>
ComputeDataLayout(const clang::ASTContext& context, const std::unordered_map<const clang::Type*, AnalysisAction::RepackedType>& types) {
  std::unordered_map<const clang::Type*, TypeInfo> layout;

  // First, add all types directly used in function signatures of the library API to the meta set
  for (const auto& [type, type_repack_info] : types) {
    if (type_repack_info.assumed_compatible) {
      auto [_, inserted] = layout.insert(std::pair {context.getCanonicalType(type), TypeInfo {}});
      if (!inserted) {
        throw std::runtime_error(
          "Failed to gather type metadata: Opaque type \"" + clang::QualType {type, 0}.getAsString() + "\" already registered");
      }
      continue;
    }

    if (type->isIncompleteType()) {
      throw std::runtime_error(
        "Cannot compute data layout of incomplete type \"" + clang::QualType {type, 0}.getAsString() + "\". Did you forget any annotations?");
    }

    if (type->isStructureType()) {
      StructInfo info;
      info.size_bits = context.getTypeSize(type);
      info.alignment_bits = context.getTypeAlign(type);

      auto [_, inserted] = layout.insert(std::pair {context.getCanonicalType(type), info});
      if (!inserted) {
        throw std::runtime_error("Failed to gather type metadata: Type \"" + clang::QualType {type, 0}.getAsString() + "\" already registered");
      }
    } else if (type->isBuiltinType() || type->isEnumeralType()) {
      SimpleTypeInfo info;
      info.size_bits = context.getTypeSize(type);
      info.alignment_bits = context.getTypeAlign(type);

      // NOTE: Non-enum types are intentionally not canonicalized since that would turn e.g. size_t into platform-specific types
      auto [_, inserted] = layout.insert(std::pair {type->isEnumeralType() ? context.getCanonicalType(type) : type, info});
      if (!inserted) {
        throw std::runtime_error("Failed to gather type metadata: Type \"" + clang::QualType {type, 0}.getAsString() + "\" already registered");
      }
    }
  }

  // Then, add information about members
  for (const auto& [type, type_repack_info] : types) {
    if (!type->isStructureType() || type_repack_info.assumed_compatible) {
      continue;
    }

    auto& info = *layout.at(context.getCanonicalType(type)).get_if_struct();

    for (auto* field : type->getAsStructureType()->getDecl()->fields()) {
      auto field_type = field->getType().getTypePtr();
      std::optional<uint64_t> array_size;
      if (auto array_type = llvm::dyn_cast<clang::ConstantArrayType>(field->getType())) {
        array_size = array_type->getSize().getZExtValue();
        field_type = array_type->getElementType().getTypePtr();
        if (llvm::isa<clang::ConstantArrayType>(field_type)) {
          throw std::runtime_error("Unsupported multi-dimensional array member \"" + field->getNameAsString() + "\" in type \"" +