Module: MilkTea::Lowering::Proc

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

Instance Method Summary collapse

Instance Method Details

#build_proc_invoke_function(expression, proc_type, captures, env_struct_type, invoke_c_name) ⇒ Object 



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

def build_proc_invoke_function(expression, proc_type, captures, env_struct_type, invoke_c_name)
  env = empty_env
  params = [IR::Param.new(name: "env", linkage_name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false)]
  parameter_setup = []

  if env_struct_type
    env_pointer_type = pointer_to(env_struct_type)
    env_pointer_name = "__mt_proc_env_ptr"
    env[:scopes].last[env_pointer_name] = local_binding(type: env_pointer_type, linkage_name: env_pointer_name, mutable: false, pointer: false)
    parameter_setup << IR::LocalDecl.new(
      name: env_pointer_name,
      linkage_name: env_pointer_name,
      type: env_pointer_type,
      value: IR::Cast.new(
        target_type: env_pointer_type,
        expression: IR::Name.new(name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false),
        type: env_pointer_type,
      ),
    )

    env_pointer = IR::Name.new(name: env_pointer_name, type: env_pointer_type, pointer: false)
    captures.each do |capture|
      capture_c_name = "__mt_capture_#{capture[:name]}"
      env[:scopes].last[capture[:name]] = local_binding(type: capture[:type], linkage_name: capture_c_name, mutable: false, pointer: false)
      parameter_setup << IR::LocalDecl.new(
        name: capture[:name],
        linkage_name: capture_c_name,
        type: capture[:type],
        value: IR::Member.new(receiver: env_pointer, member: capture[:field_name], type: capture[:type]),
      )
    end
  end

  expression.params.each_with_index do |param, index|
    type = proc_type.params.fetch(index).type
    linkage_name = c_local_name(param.name)
    if array_type?(type)
      input_linkage_name = "#{linkage_name}_input"
      params << IR::Param.new(name: param.name, linkage_name: input_linkage_name, type:, pointer: false)
      env[:scopes].last[param.name] = local_binding(type:, linkage_name:, mutable: false, pointer: false)
      parameter_setup << IR::LocalDecl.new(
        name: param.name,
        linkage_name:,
        type:,
        value: IR::Name.new(name: input_linkage_name, type:, pointer: false),
      )
    else
      env[:scopes].last[param.name] = local_binding(type:, linkage_name:, mutable: false, pointer: false)
      params << IR::Param.new(name: param.name, linkage_name:, type:, pointer: false)
    end
  end

  body = parameter_setup + lower_block(expression.body, env:, active_defers: [], return_type: proc_type.return_type, loop_flow: nil, allow_return: true)
  IR::Function.new(name: invoke_c_name, linkage_name: invoke_c_name, params:, return_type: proc_type.return_type, body:, entry_point: false)
end

#build_proc_noop_release_function(release_linkage_name) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 391

def build_proc_noop_release_function(release_linkage_name)
  IR::Function.new(
    name: release_linkage_name,
    linkage_name: release_linkage_name,
    params: [IR::Param.new(name: "env", linkage_name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false)],
    return_type: @ctx.types.fetch("void"),
    body: [IR::ReturnStmt.new(value: nil)],
    entry_point: false,
  )
end

#build_proc_noop_retain_function(retain_c_name) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 402

def build_proc_noop_retain_function(retain_c_name)
  IR::Function.new(
    name: retain_c_name,
    linkage_name: retain_c_name,
    params: [IR::Param.new(name: "env", linkage_name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false)],
    return_type: @ctx.types.fetch("void"),
    body: [IR::ReturnStmt.new(value: nil)],
    entry_point: false,
  )
end

#build_proc_release_function(release_linkage_name, env_struct_type) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 62

def build_proc_release_function(release_linkage_name, env_struct_type)
  return build_proc_noop_release_function(release_linkage_name) unless env_struct_type

  env_pointer_type = pointer_to(env_struct_type)
  env_pointer = IR::Name.new(name: "__mt_proc_env_ptr", type: env_pointer_type, pointer: false)
  ref_count = IR::Member.new(receiver: env_pointer, member: "__mt_ref_count", type: @ctx.types.fetch("ptr_uint"))

  free_body = []

  if contains_proc_storage_type?(env_struct_type)
    env_struct_type.fields.reject { |name, _| name == "__mt_ref_count" }.each do |field_name, field_type|
      next unless contains_proc_storage_type?(field_type)

      member = IR::Member.new(receiver: env_pointer, member: field_name, type: field_type)
      free_body.concat(lower_proc_contained_release_statements(member, field_type))
    end
  end

  free_body << IR::ExpressionStmt.new(
    expression: IR::Call.new(
      callee: "mt_async_free",
      arguments: [IR::Name.new(name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false)],
      type: @ctx.types.fetch("void"),
    ),
  )

  IR::Function.new(
    name: release_linkage_name,
    linkage_name: release_linkage_name,
    params: [IR::Param.new(name: "env", linkage_name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false)],
    return_type: @ctx.types.fetch("void"),
    body: [
      IR::LocalDecl.new(
        name: "__mt_proc_env_ptr",
        linkage_name: "__mt_proc_env_ptr",
        type: env_pointer_type,
        value: IR::Cast.new(target_type: env_pointer_type, expression: IR::Name.new(name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false), type: env_pointer_type),
      ),
      IR::Assignment.new(target: ref_count, operator: "-=", value: IR::IntegerLiteral.new(value: 1, type: @ctx.types.fetch("ptr_uint"))),
      IR::IfStmt.new(
        condition: IR::Binary.new(operator: "==", left: ref_count, right: IR::IntegerLiteral.new(value: 0, type: @ctx.types.fetch("ptr_uint")), type: @ctx.types.fetch("bool")),
        then_body: free_body,
        else_body: nil,
      ),
      IR::ReturnStmt.new(value: nil),
    ],
    entry_point: false,
  )
end

#build_proc_retain_function(retain_c_name, env_struct_type) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 112

def build_proc_retain_function(retain_c_name, env_struct_type)
  return build_proc_noop_retain_function(retain_c_name) unless env_struct_type

  env_pointer_type = pointer_to(env_struct_type)
  env_pointer = IR::Name.new(name: "__mt_proc_env_ptr", type: env_pointer_type, pointer: false)
  ref_count = IR::Member.new(receiver: env_pointer, member: "__mt_ref_count", type: @ctx.types.fetch("ptr_uint"))
  IR::Function.new(
    name: retain_c_name,
    linkage_name: retain_c_name,
    params: [IR::Param.new(name: "env", linkage_name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false)],
    return_type: @ctx.types.fetch("void"),
    body: [
      IR::LocalDecl.new(
        name: "__mt_proc_env_ptr",
        linkage_name: "__mt_proc_env_ptr",
        type: env_pointer_type,
        value: IR::Cast.new(target_type: env_pointer_type, expression: IR::Name.new(name: "__mt_proc_env", type: proc_env_pointer_type, pointer: false), type: env_pointer_type),
      ),
      IR::Assignment.new(target: ref_count, operator: "+=", value: IR::IntegerLiteral.new(value: 1, type: @ctx.types.fetch("ptr_uint"))),
      IR::ReturnStmt.new(value: nil),
    ],
    entry_point: false,
  )
end

#collect_proc_captures_from_expression(expression, env, local_scopes, captures) ⇒ Object 



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

def collect_proc_captures_from_expression(expression, env, local_scopes, captures)
  return unless expression

  case expression
  when AST::Identifier
    return if local_scopes.any? { |scope| scope.key?(expression.name) }

    if (binding = proc_capture_binding(expression.name, env))
      captures[expression.name] ||= { name: expression.name, field_name: expression.name, type: binding[:type] }
    end
  when AST::MemberAccess
    collect_proc_captures_from_expression(expression.receiver, env, local_scopes, captures)
  when AST::IndexAccess
    collect_proc_captures_from_expression(expression.receiver, env, local_scopes, captures)
    collect_proc_captures_from_expression(expression.index, env, local_scopes, captures)
  when AST::Specialization
    collect_proc_captures_from_expression(expression.callee, env, local_scopes, captures)
    expression.arguments.each { |argument| collect_proc_captures_from_expression(argument.value, env, local_scopes, captures) }
  when AST::Call
    collect_proc_captures_from_expression(expression.callee, env, local_scopes, captures)
    expression.arguments.each { |argument| collect_proc_captures_from_expression(argument.value, env, local_scopes, captures) }
  when AST::UnaryOp
    collect_proc_captures_from_expression(expression.operand, env, local_scopes, captures)
  when AST::BinaryOp
    collect_proc_captures_from_expression(expression.left, env, local_scopes, captures)
    collect_proc_captures_from_expression(expression.right, env, local_scopes, captures)
  when AST::IfExpr
    collect_proc_captures_from_expression(expression.condition, env, local_scopes, captures)
    collect_proc_captures_from_expression(expression.then_expression, env, local_scopes, captures)
    collect_proc_captures_from_expression(expression.else_expression, env, local_scopes, captures)
  when AST::MatchExpr
    collect_proc_captures_from_expression(expression.expression, env, local_scopes, captures)
    expression.arms.each do |arm|
      collect_proc_captures_from_expression(arm.pattern, env, local_scopes, captures)
      arm_scopes = arm.binding_name ? local_scopes + [{ arm.binding_name => true }] : local_scopes
      collect_proc_captures_from_expression(arm.value, env, arm_scopes, captures)
    end
  when AST::UnsafeExpr
    collect_proc_captures_from_expression(expression.expression, env, local_scopes, captures)
  when AST::AwaitExpr
    collect_proc_captures_from_expression(expression.expression, env, local_scopes, captures)
  when AST::FormatString
    expression.parts.each do |part|
      collect_proc_captures_from_expression(part.expression, env, local_scopes, captures) if part.is_a?(AST::FormatExprPart)
    end
  when AST::ProcExpr, AST::TypeRef, AST::FunctionType, AST::ProcType,
        AST::SizeofExpr, AST::AlignofExpr, AST::OffsetofExpr,
        AST::IntegerLiteral, AST::FloatLiteral, AST::StringLiteral,
        AST::BooleanLiteral, AST::NullLiteral
    nil
  else
    raise LoweringError.new("unsupported proc capture expression #{expression.class.name}", line: 0, column: 0, path: @ctx.current_analysis_path)
  end
end

#collect_proc_captures_from_statement(statement, env, local_scopes, captures) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 150

def collect_proc_captures_from_statement(statement, env, local_scopes, captures)
  case statement
  when AST::LocalDecl
    collect_proc_captures_from_expression(statement.value, env, local_scopes, captures) if statement.value
    local_scopes.last[statement.name] = true
  when AST::Assignment
    collect_proc_captures_from_expression(statement.target, env, local_scopes, captures)
    collect_proc_captures_from_expression(statement.value, env, local_scopes, captures)
  when AST::IfStmt
    statement.branches.each do |branch|
      collect_proc_captures_from_expression(branch.condition, env, local_scopes, captures)
      collect_proc_captures_from_statements(branch.body, env, local_scopes + [{}], captures)
    end
    collect_proc_captures_from_statements(statement.else_body, env, local_scopes + [{}], captures) if statement.else_body
  when AST::MatchStmt
    collect_proc_captures_from_expression(statement.expression, env, local_scopes, captures)
    statement.arms.each do |arm|
      collect_proc_captures_from_expression(arm.pattern, env, local_scopes, captures)
      collect_proc_captures_from_statements(arm.body, env, local_scopes + [{}], captures)
    end
  when AST::UnsafeStmt
    collect_proc_captures_from_statements(statement.body, env, local_scopes + [{}], captures)
  when AST::StaticAssert
    collect_proc_captures_from_expression(statement.condition, env, local_scopes, captures)
    collect_proc_captures_from_expression(statement.message, env, local_scopes, captures)
  when AST::ForStmt
    statement.iterables.each { |iterable| collect_proc_captures_from_expression(iterable, env, local_scopes, captures) }
    collect_proc_captures_from_statements(statement.body, env, local_scopes + [statement.names.each_with_object({}) { |name, scope| scope[name] = true }], captures)
  when AST::WhileStmt
    collect_proc_captures_from_expression(statement.condition, env, local_scopes, captures)
    collect_proc_captures_from_statements(statement.body, env, local_scopes + [{}], captures)
  when AST::ReturnStmt
    collect_proc_captures_from_expression(statement.value, env, local_scopes, captures) if statement.value
  when AST::DeferStmt
    collect_proc_captures_from_statements(statement.body, env, local_scopes + [{}], captures)
  when AST::ExpressionStmt
    collect_proc_captures_from_expression(statement.expression, env, local_scopes, captures)
  when AST::BreakStmt, AST::ContinueStmt, AST::PassStmt
    nil
  else
    raise LoweringError.new("unsupported proc capture statement #{statement.class.name}", line: 0, column: 0, path: @ctx.current_analysis_path)
  end
end

#collect_proc_captures_from_statements(statements, env, local_scopes, captures) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 144

def collect_proc_captures_from_statements(statements, env, local_scopes, captures)
  statements.each do |statement|
    collect_proc_captures_from_statement(statement, env, local_scopes, captures)
  end
end

#expression_contains_proc_expr?(expression) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/milk_tea/core/lowering/proc.rb', line 361

def expression_contains_proc_expr?(expression)
  return false unless expression

  case expression
  when AST::ProcExpr
    true
  when AST::MemberAccess
    expression_contains_proc_expr?(expression.receiver)
  when AST::IndexAccess
    expression_contains_proc_expr?(expression.receiver) || expression_contains_proc_expr?(expression.index)
  when AST::UnaryOp
    expression_contains_proc_expr?(expression.operand)
  when AST::BinaryOp
    expression_contains_proc_expr?(expression.left) || expression_contains_proc_expr?(expression.right)
  when AST::IfExpr
    expression_contains_proc_expr?(expression.condition) ||
      expression_contains_proc_expr?(expression.then_expression) ||
      expression_contains_proc_expr?(expression.else_expression)
  when AST::UnsafeExpr
    expression_contains_proc_expr?(expression.expression)
  when AST::AwaitExpr
    expression_contains_proc_expr?(expression.expression)
  when AST::Call
    expression_contains_proc_expr?(expression.callee) || expression.arguments.any? { |argument| expression_contains_proc_expr?(argument.value) }
  when AST::Specialization
    expression_contains_proc_expr?(expression.callee)
  else
    false
  end
end

#lower_async_frame_proc_nullable_release_statements(value_expression, type) ⇒ Object

Alias used for async frame fields (always guarded).



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# File 'lib/milk_tea/core/lowering/proc.rb', line 284

def lower_async_frame_proc_nullable_release_statements(value_expression, type)
  lower_proc_contained_lifecycle_statements(value_expression, type, :release, guarded: true)
end

#lower_proc_contained_lifecycle_statements(value_expression, type, mode, guarded: false) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 292

def lower_proc_contained_lifecycle_statements(value_expression, type, mode, guarded: false)
  return [] unless contains_proc_storage_type?(type)

  if proc_type?(type)
    if mode == :release && guarded
      invoke_member = IR::Member.new(receiver: value_expression, member: "invoke", type: proc_invoke_function_type(type))
      release_stmt = IR::ExpressionStmt.new(expression: lower_proc_release_expression(value_expression, type))
      return [IR::IfStmt.new(condition: invoke_member, then_body: [release_stmt], else_body: nil)]
    end
    expression = mode == :retain ? lower_proc_retain_expression(value_expression, type) : lower_proc_release_expression(value_expression, type)
    return [IR::ExpressionStmt.new(expression:)]
  end

  case type
  when Types::Struct, Types::StructInstance
    statements = []
    type.fields.each do |field_name, field_type|
      next unless contains_proc_storage_type?(field_type)

      member = IR::Member.new(receiver: value_expression, member: field_name, type: field_type)
      statements.concat(lower_proc_contained_lifecycle_statements(member, field_type, mode, guarded:))
    end
    statements
  when Types::Nullable
    []
  else
    raise LoweringError.new("unsupported proc lifecycle container #{type.class.name}", line: 0, column: 0, path: @ctx.current_analysis_path)
  end
end

#lower_proc_contained_release_statements(value_expression, type) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 273

def lower_proc_contained_release_statements(value_expression, type)
  lower_proc_contained_lifecycle_statements(value_expression, type, :release)
end

#lower_proc_contained_retain_statements(value_expression, type) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 288

def lower_proc_contained_retain_statements(value_expression, type)
  lower_proc_contained_lifecycle_statements(value_expression, type, :retain)
end

#lower_proc_nullable_release_statements(value_expression, type) ⇒ Object

Null-guarded release: safe when value may be zero-initialized (var locals, async frame fields). Wraps each proc release in if (proc.invoke) { proc.release(proc.env); }.



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# File 'lib/milk_tea/core/lowering/proc.rb', line 279

def lower_proc_nullable_release_statements(value_expression, type)
  lower_proc_contained_lifecycle_statements(value_expression, type, :release, guarded: true)
end

#lower_proc_release_expression(proc_expression, _proc_type) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 257

def lower_proc_release_expression(proc_expression, _proc_type)
  IR::Call.new(
    callee: IR::Member.new(receiver: proc_expression, member: "release", type: proc_release_function_type),
    arguments: [IR::Member.new(receiver: proc_expression, member: "env", type: proc_env_pointer_type)],
    type: @ctx.types.fetch("void"),
  )
end

#lower_proc_retain_expression(proc_expression, _proc_type) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 265

def lower_proc_retain_expression(proc_expression, _proc_type)
  IR::Call.new(
    callee: IR::Member.new(receiver: proc_expression, member: "retain", type: proc_retain_function_type),
    arguments: [IR::Member.new(receiver: proc_expression, member: "env", type: proc_env_pointer_type)],
    type: @ctx.types.fetch("void"),
  )
end

#lower_proc_selective_retain_statements(ir_value, original_ast, type) ⇒ Object

Retain only proc fields that did NOT originate from a fresh proc expression in original_ast. Fresh proc expressions already carry refcount=1; retaining them would over-count. For existing proc values (variables, member accesses, return values), we retain to share ownership. When original_ast is a struct aggregate literal (AST::Call), fields are matched by name.



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# File 'lib/milk_tea/core/lowering/proc.rb', line 326

def lower_proc_selective_retain_statements(ir_value, original_ast, type)
  return [] unless contains_proc_storage_type?(type)

  if proc_type?(type)
    # If the direct expression is a fresh proc, ownership transfers — no retain needed.
    return [] if expression_contains_proc_expr?(original_ast)

    return [IR::ExpressionStmt.new(expression: lower_proc_retain_expression(ir_value, type))]
  end

  case type
  when Types::Struct, Types::StructInstance
    statements = []
    type.fields.each do |field_name, field_type|
      next unless contains_proc_storage_type?(field_type)

      # Try to extract the AST sub-expression for this specific field when the source
      # is a struct aggregate literal (struct-name(field = value, ...)).
      ast_field_source = if original_ast.is_a?(AST::Call)
        original_ast.arguments.find { |arg| arg.name == field_name }&.value
      end
      # Fall back to the whole RHS expression (conservative — treats as existing proc → retains).
      ast_field_source ||= original_ast

      member = IR::Member.new(receiver: ir_value, member: field_name, type: field_type)
      statements.concat(lower_proc_selective_retain_statements(member, ast_field_source, field_type))
    end
    statements
  when Types::Nullable
    []
  else
    []
  end
end

#proc_capture_binding(name, env) ⇒ Object 



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

def proc_capture_binding(name, env)
  env[:scopes].reverse_each do |scope|
    return scope[name] if scope.key?(name)
  end

  nil
end

#proc_capture_entries(expression, env) ⇒ Object 



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# File 'lib/milk_tea/core/lowering/proc.rb', line 137

def proc_capture_entries(expression, env)
  local_scopes = [expression.params.each_with_object({}) { |param, names| names[param.name] = true }]
  captures = {}
  collect_proc_captures_from_statements(expression.body, env, local_scopes, captures)
  captures.values
end