Module: MilkTea::Lowering::Declarations

Included in:
MilkTea::Lowerer
Defined in:
lib/milk_tea/core/lowering/declarations.rb

Instance Method Summary collapse

Instance Method Details

#ensure_registered_storage_type_types(type, seen = {}) ⇒ Object

Register C struct typedefs for every tuple type reachable from a module-storage type (consts and globals). ensure_tuple_struct is normally called while lowering tuple expressions, so a tuple that only appears in static storage never gets its mt_tuple_... typedef emitted; the C compiler then fails with "unknown type name".



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 87

def ensure_registered_storage_type_types(type, seen = {})
  return if type.nil? || seen[type]

  seen[type] = true
  if type.is_a?(Types::Tuple)
    ensure_tuple_struct(type)
    type.element_types.each { |element_type| ensure_registered_storage_type_types(element_type, seen) }
  end

  case type
  when Types::Nullable
    ensure_registered_storage_type_types(type.base, seen)
  when Types::Span
    ensure_registered_storage_type_types(type.element_type, seen)
  when Types::Task
    ensure_registered_storage_type_types(type.result_type, seen)
  when Types::GenericInstance, Types::StructInstance, Types::VariantInstance
    type.arguments.each do |argument|
      ensure_registered_storage_type_types(argument, seen) unless argument.is_a?(Types::LiteralTypeArg)
    end
  end

  if type.respond_to?(:fields) && type.fields
    type.fields.each_value { |field_type| ensure_registered_storage_type_types(field_type, seen) }
  end
  if type.respond_to?(:arms)
    type.arms.each_value do |arm_fields|
      arm_fields.each_value { |field_type| ensure_registered_storage_type_types(field_type, seen) }
    end
  end
end

#expanded_declarations ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 6

def expanded_declarations
  @ctx.ast.declarations.flat_map do |decl|
    case decl
    when AST::WhenStmt
      val = compile_time_const_value(decl.discriminant)
      next [decl] if val.nil?

      chosen = decl.branches.find { |b| val == compile_time_const_value(b.pattern) }
      body = chosen ? chosen.body : (decl.else_body || [])
      body
    else
      [decl]
    end
  end
end

#lower_const_value_literal(type, const_value) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 119

def lower_const_value_literal(type, const_value)
  case const_value
  when Integer
    value = if type.respond_to?(:integer_width) && (width = type.integer_width) && width < 64
      mask = (1 << width) - 1
      masked = const_value & mask
      if type.respond_to?(:unsigned_integer?) && !type.unsigned_integer? && masked >= (1 << (width - 1))
        masked - (1 << width)
      else
        masked
      end
    else
      const_value
    end
    IR::IntegerLiteral.new(value:, type:)
  when Float
    IR::FloatLiteral.new(value: const_value, type:)
  when String
    IR::StringLiteral.new(value: const_value, type:, cstring: false)
  when TrueClass, FalseClass
    IR::BooleanLiteral.new(value: const_value, type:)
  when Array
    element_type = type.respond_to?(:arguments) ? type.arguments.first : @ctx.types["int"]
    elements = const_value.map do |element|
      lower_const_value_literal(element_type, element)
    end
    IR::ArrayLiteral.new(type:, elements:)
  when Hash
    fields = const_value.map do |name, field_value|
      field_type = type.field(name)
      raise LoweringError.new("constant struct field #{name} not found in #{type}", line: 0, column: 0, path: @ctx.current_analysis_path) unless field_type
      IR::AggregateField.new(name:, value: lower_const_value_literal(field_type, field_value))
    end
    IR::AggregateLiteral.new(type:, fields:)
  when CompileTime::VariantValue
    arm_field_types = type.respond_to?(:arm) ? (type.arm(const_value.arm) || {}) : {}
    fields = const_value.fields.map do |field_name, field_value|
      field_type = arm_field_types[field_name]
      raise LoweringError.new("constant variant arm #{const_value.arm} field #{field_name} not found in #{type}", line: 0, column: 0, path: @ctx.current_analysis_path) unless field_type
      IR::AggregateField.new(name: field_name, value: lower_const_value_literal(field_type, field_value))
    end
    IR::VariantLiteral.new(type:, arm_name: const_value.arm, fields:)
  else
    raise LoweringError.new("unsupported const value type #{const_value.class}", line: 0, column: 0, path: @ctx.current_analysis_path)
  end
end

#lower_constants ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 22

def lower_constants
  expanded_declarations.grep(AST::ConstDecl).filter_map do |decl|
    type = @ctx.values.fetch(decl.name).type
    const_value = @ctx.values.fetch(decl.name).const_value
    ensure_registered_storage_type_types(type)

    next if type == Types::BUILTIN_TYPE_META_TYPE

    if !const_value.nil? && (decl.value.is_a?(AST::Call) || decl.value.is_a?(AST::Specialization))
      value = lower_const_value_literal(type, const_value)
    elsif !const_value.nil? && (decl.block_body || decl.value.is_a?(AST::ExpressionList))
      if const_value.is_a?(Array) && const_value.empty? && decl.value.is_a?(AST::ExpressionList) && !decl.value.elements.empty?
        value = lower_static_storage_initializer(decl.value, env: empty_env, expected_type: type)
      else
        value = lower_const_value_literal(type, const_value)
      end
    elsif decl.block_body || decl.value.is_a?(AST::ExpressionList)
      raise LoweringError.new("constant #{decl.name} has no compile-time value", line: decl.line, column: decl.column, path: @ctx.current_analysis_path)
    else
      value = lower_static_storage_initializer(decl.value, env: empty_env, expected_type: type)
      if (decl.value.is_a?(AST::Call) || decl.value.is_a?(AST::Specialization)) && static_initializer_ir_has_call?(value)
        raise LoweringError.new("constant #{decl.name} initializer is not a compile-time value", line: decl.line, column: decl.column, path: @ctx.current_analysis_path)
      end
    end

    IR::Constant.new(name: decl.name, linkage_name: value_c_name(decl.name), type:, value:, line: decl.line, path: @ctx.current_analysis_path)
  end
end

#lower_enums ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 259

def lower_enums
  expanded_declarations.filter_map do |decl|
    case decl
    when AST::EnumDecl, AST::FlagsDecl
      enum_type = @ctx.types.fetch(decl.name)
      backing_type = enum_type.backing_type
      members = decl.members.map do |member|
        value = if member.value
                  lower_expression(member.value, env: empty_env, expected_type: backing_type)
                else
                  IR::IntegerLiteral.new(value: enum_type.member_value(member.name), type: backing_type)
                end
        IR::EnumMember.new(name: member.name, linkage_name: enum_member_c_name(enum_type, member.name), value:)
      end

      IR::EnumDecl.new(
        name: decl.name,
        linkage_name: c_type_name(enum_type),
        backing_type:,
        members:,
        flags: decl.is_a?(AST::FlagsDecl),
      )
    end
  end
end

#lower_globals ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 166

def lower_globals
  expanded_declarations.filter_map do |decl|
    next unless decl.is_a?(AST::VarDecl) || decl.is_a?(AST::EventDecl)

    type = @ctx.values.fetch(decl.name).type
    ensure_registered_storage_type_types(type)
    ensure_event_runtime(type) if type.is_a?(Types::Event)
    value = if decl.is_a?(AST::VarDecl) && decl.value
      lower_static_storage_initializer(decl.value, env: empty_env, expected_type: type)
    else
      IR::ZeroInit.new(type: type)
    end
    IR::Global.new(name: decl.name, linkage_name: value_c_name(decl.name), type:, value:)
  end
end

#lower_imported_external_opaques ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 194

def lower_imported_external_opaques
  each_raw_module_analysis.flat_map do |analysis|
    analysis.ast.declarations.grep(AST::OpaqueDecl).filter_map do |decl|
      opaque_type = analysis.types.fetch(decl.name)
      next unless forward_declarable_external_opaque?(opaque_type)

      IR::OpaqueDecl.new(name: decl.name, linkage_name: opaque_c_type_name(opaque_type), forward_declarable: true, source_module: analysis.module_name)
    end
  end.uniq { |decl| decl.linkage_name }
end

#lower_opaques ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 182

def lower_opaques
  expanded_declarations.grep(AST::OpaqueDecl).map do |decl|
    opaque_type = @ctx.opaque_types.fetch(decl.name)
    IR::OpaqueDecl.new(
      name: decl.name,
      linkage_name: opaque_c_type_name(opaque_type),
      forward_declarable: opaque_forward_declarable?(opaque_type),
      source_module: @ctx.module_name,
    )
  end
end

#lower_static_assert(statement, env:) ⇒ Object

Raises:



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 211

def lower_static_assert(statement, env:)
  condition_value = compile_time_const_value(statement.condition, env:)
  raise LoweringError.new("static_assert condition must lower to a compile-time bool constant", line: 0, column: 0, path: @ctx.current_analysis_path) unless condition_value == true || condition_value == false

  IR::StaticAssert.new(
    condition: IR::BooleanLiteral.new(value: condition_value, type: @ctx.types.fetch("bool")),
    message: lower_expression(statement.message, env:, expected_type: @ctx.types.fetch("str")),
  )
end

#lower_static_asserts ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 205

def lower_static_asserts
  expanded_declarations.grep(AST::StaticAssert).map do |statement|
    lower_static_assert(statement, env: empty_env)
  end
end

#lower_struct_decl(decl, qualified_name, results) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 231

def lower_struct_decl(decl, qualified_name, results)
  struct_type = @ctx.struct_types.fetch(qualified_name)
  fields = decl.fields.map do |field|
    IR::Field.new(name: field.name, type: struct_type.field(field.name))
  end
  decl.events.each do |event_decl|
    event_type = struct_type.event(event_decl.name)
    ensure_event_runtime(event_type)
    fields << IR::Field.new(name: event_type.hidden_field_name, type: event_type)
  end

  results << IR::StructDecl.new(name: decl.name, linkage_name: c_type_name(struct_type), fields:, packed: decl.packed, alignment: decl.alignment, source_module: @ctx.module_name)

  decl.nested_types.each do |nested|
    lower_struct_decl(nested, "#{qualified_name}.#{nested.name}", results)
  end
end

#lower_structs ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 221

def lower_structs
  expanded_declarations.grep(AST::StructDecl).filter_map do |decl|
    next unless decl.type_params.empty?

    results = []
    lower_struct_decl(decl, decl.name, results)
    results
  end.flatten
end

#lower_unions ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 249

def lower_unions
  expanded_declarations.grep(AST::UnionDecl).map do |decl|
    union_type = @ctx.union_types.fetch(decl.name)
    fields = decl.fields.map do |field|
      IR::Field.new(name: field.name, type: union_type.field(field.name))
    end
    IR::UnionDecl.new(name: decl.name, linkage_name: c_type_name(union_type), fields:, source_module: @ctx.module_name)
  end
end

#lower_variants ⇒ Object 



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# File 'lib/milk_tea/core/lowering/declarations.rb', line 285

def lower_variants
  expanded_declarations.filter_map do |decl|
    next unless decl.is_a?(AST::VariantDecl)

    variant_type = @ctx.types.fetch(decl.name)
    next if variant_type.is_a?(Types::GenericVariantDefinition)

    outer_c = c_type_name(variant_type)
    arms = decl.arms.map do |arm|
      arm_c = "#{outer_c}_#{arm.name}"
      fields = arm.fields.map do |field|
        field_type = variant_type.arm(arm.name).fetch(field.name)
        IR::Field.new(name: field.name, type: field_type)
      end
      IR::VariantArm.new(name: arm.name, linkage_name: arm_c, fields:)
    end
    IR::VariantDecl.new(name: decl.name, linkage_name: outer_c, arms:, source_module: @ctx.module_name)
  end
end

#static_initializer_ir_has_call?(node) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/milk_tea/core/lowering/declarations.rb', line 51

def static_initializer_ir_has_call?(node)
  case node
  when IR::Call
    true
  when IR::AggregateLiteral
    node.fields.any? { |field| static_initializer_ir_has_call?(field.value) }
  when IR::ArrayLiteral
    node.elements.any? { |element| static_initializer_ir_has_call?(element) }
  when IR::VariantLiteral
    node.fields.any? { |field| static_initializer_ir_has_call?(field.value) }
  when IR::Binary
    static_initializer_ir_has_call?(node.left) || static_initializer_ir_has_call?(node.right)
  when IR::Unary
    static_initializer_ir_has_call?(node.operand)
  when IR::Conditional
    static_initializer_ir_has_call?(node.condition) || static_initializer_ir_has_call?(node.then_expression) || static_initializer_ir_has_call?(node.else_expression)
  when IR::Cast
    static_initializer_ir_has_call?(node.expression)
  when IR::AddressOf
    static_initializer_ir_has_call?(node.expression)
  when IR::Member
    static_initializer_ir_has_call?(node.receiver)
  when IR::Index, IR::CheckedIndex, IR::CheckedSpanIndex, IR::NullableIndex, IR::NullableSpanIndex
    static_initializer_ir_has_call?(node.receiver) || static_initializer_ir_has_call?(node.index)
  when IR::ReinterpretExpr
    static_initializer_ir_has_call?(node.expression)
  else
    false
  end
end