Module: Wardite::BinaryLoader

Extended by:
Leb128Helper, ValueHelper
Defined in:
lib/wardite/load.rb

Class Method Summary collapse

Methods included from Leb128Helper

fetch_sleb128, fetch_uleb128

Methods included from ValueHelper

F32, F64, I32, I64

Class Method Details

.assert_read(sbuf, n) ⇒ Object 



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# File 'lib/wardite/load.rb', line 911

def self.assert_read(sbuf, n)
  ret = sbuf.read n
  if !ret
    raise LoadError, "too short section size"
  end
  if ret.size != n
    raise LoadError, "too short section size"
  end
  ret
end

.code_body(buf) ⇒ Object 



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# File 'lib/wardite/load.rb', line 617

def self.code_body(buf)
  dest = [] #: Array[[Symbol, Symbol, Array[operandItem], Integer?, Integer?]]
  # HINT: [symname, index of op, index of else, index of end]
  branching_stack = [] #: Array[[Symbol, Integer, Integer, Integer]]
  fixed_stack = [] #: Array[[Symbol, Integer, Integer, Integer]]
  while c = buf.read(1)
    namespace, code, operand_types = resolve_code(c, buf)
    operand = [] #: Array[operandItem]
    operand_types.each do |typ|
      case typ
      when :u8
        ope = buf.read 1
        if ! ope
          raise LoadError, "buffer too short"
        end
        operand << ope.ord
      when :u32
        operand << fetch_uleb128(buf)
      when :u32_vec
        len = fetch_uleb128(buf)
        vec = [] #: Array[Integer]
        len.times do
          vec << fetch_uleb128(buf)
        end
        operand << vec
      when :i32
        operand << fetch_sleb128(buf)
      when :i64
        operand << fetch_sleb128(buf, max_level: 16)
      when :f32
        data = buf.read 4
        if !data || data.size != 4
          raise LoadError, "buffer too short"
        end
        v = data.unpack("e")[0]
        raise "String#unpack is broken" if !v.is_a?(Float)
        operand << v
      when :f64
        data = buf.read 8
        if !data || data.size != 8
          raise LoadError, "buffer too short"
        end
        v = data.unpack("E")[0]
        raise "String#unpack is broken" if !v.is_a?(Float)
        operand << v
      when :u8_block
        block_ope = buf.read 1
        if ! block_ope
          raise LoadError, "buffer too short for if"
        end
        if block_ope.ord == 0x40
          operand << Block.void
        else
          operand << Block.new([block_ope.ord])
        end
      else
        $stderr.puts "warning: unknown type #{typ.inspect}. defaulting to u32"
        operand << fetch_uleb128(buf)
      end         
    end

    # HINT: [namespace, code, operand, else_pos, end_pos]
    dest << [namespace, code, operand, nil, nil]
    if code == :block || code == :loop || code == :if
      branching_stack << [code, dest.size - 1, -1, -1]
    elsif code == :else
      if branching_stack.empty?
        raise "broken sequence: unmatched else"
      else
        last = branching_stack.pop || raise("[BUG] empty pop")
        if last[0] != :if
          raise "broken sequence: else without if"
        end
        branching_stack << [last[0], last[1], dest.size - 1, -1]
      end
    elsif code == :end
      unless branching_stack.empty?
        last = branching_stack.pop || raise("[BUG] empty pop")
        fixed_stack << [last[0], last[1], last[2], dest.size - 1]
      end
    end
  end

  fixed_stack.each do |(sym, begin_idx, else_idx, end_idx)|
    if end_idx == -1
      raise "broken sequence: branching without end"
    end
    case sym
    when :block, :loop
      dest[begin_idx][-1] = end_idx
    when :if
      dest[begin_idx][-2] = else_idx == -1 ? end_idx : else_idx
      dest[begin_idx][-1] = end_idx
    else
      raise "[BUG] unknown sym #{sym.inspect}"
    end
  end
  dest
rescue => e
  require "pp"
  $stderr.puts "parsed:::"
  $stderr.puts "#{dest.pretty_inspect}"
  $stderr.puts "code = #{code}"
  raise e
end

.code_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 577

def self.code_section
  dest = CodeSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    ilen = fetch_uleb128(sbuf)
    code = assert_read(sbuf, ilen)
    last_code = code[-1]
    if ! last_code
      raise "[BUG] empty code fetched" # guard for steep check
    end
    if last_code.ord != 0x0b
      $stderr.puts "warning: instruction not ended with inst end(0x0b): 0x0#{last_code.ord}" 
    end
    cbuf = StringIO.new(code)
    locals_count = [] #: Array[Integer]
    locals_type = [] #: Array[Symbol]
    locals_len = fetch_uleb128(cbuf)
    locals_len.times do
      type_count = fetch_uleb128(cbuf)
      locals_count << type_count
      value_type = assert_read(cbuf, 1)&.ord
      locals_type << Op.i2type(value_type || -1)
    end
    body = code_body(cbuf)
    
    dest.func_codes << CodeSection::CodeBody.new do |b|
      b.locals_count = locals_count
      b.locals_type = locals_type
      b.body = body
    end
  end
  dest
end

.data_count_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 787

def self.data_count_section
  size = fetch_uleb128(@buf)
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))
  count = fetch_uleb128(sbuf)
  dest = DataCountSection.new(count)
  dest.size = size
  dest
end

.data_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 740

def self.data_section
  dest = DataSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    data_type = fetch_uleb128(sbuf)
    case data_type
    when 0x0
      # active
      code = fetch_insn_while_end(sbuf)
      ops = code_body(StringIO.new(code))
      offset = decode_expr(ops)
      len = fetch_uleb128(sbuf)
      data = sbuf.read len
      if !data
        raise LoadError, "buffer too short"
      end
      segment = DataSection::Segment.new do |seg|
        seg.mode = :active
        seg.mem_index = 0 # memory index
        seg.offset = offset
        seg.data = data
      end
      dest.segments << segment
    when 0x1
      # passive
      dsize = fetch_uleb128(sbuf)
      data = sbuf.read dsize
      if !data
        raise LoadError, "data too short"
      end
      segment = DataSection::Segment.new do |seg|
        seg.mode = :passive
        seg.mem_index = 0 # unused
        seg.offset = 0 # unused
        seg.data = data
      end
      dest.segments << segment
    end
  end
  dest
end

.decode_expr(ops) ⇒ Object 



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# File 'lib/wardite/load.rb', line 815

def self.decode_expr(ops)
  # sees first opcode
  op = ops.first
  if !op
    raise LoadError, "empty opcodes"
  end
  case op[1]
  when :i32_const
    arg = op[2][0]
    if !arg.is_a?(Integer)
      raise "Invalid definition of operand"
    end
    return arg
  else
    raise "Unimplemented offset op: #{op.inspect}"
  end
end

.decode_global_expr(ops) ⇒ Object 



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# File 'lib/wardite/load.rb', line 835

def self.decode_global_expr(ops)
  # sees first opcode
  op = ops.first
  if !op
    raise LoadError, "empty opcodes"
  end
  case op[1]
  when :i32_const
    arg = op[2][0]
    if !arg.is_a?(Integer)
      raise "Invalid definition of operand"
    end
    return I32(arg)
  when :i64_const
    arg = op[2][0]
    if !arg.is_a?(Integer)
      raise "Invalid definition of operand"
    end
    return I64(arg)
  when :f32_const
    arg = op[2][0]
    if !arg.is_a?(Float)
      raise "Invalid definition of operand"
    end
    return F32(arg)
  when :f64_const
    arg = op[2][0]
    if !arg.is_a?(Float)
      raise "Invalid definition of operand"
    end
    return F64(arg)
  else
    raise "Unimplemented offset op: #{op.inspect}"
  end
end

.elem_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 474

def self.elem_section
  dest = ElemSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    etype = fetch_uleb128(sbuf)
    case etype
    when 0x0 # expr, vec(funcidx)
      dest.table_indices << 0 # default and fixed to table[0]

      code = fetch_insn_while_end(sbuf)
      ops = code_body(StringIO.new(code))
      offset = decode_expr(ops)
      dest.table_offsets << offset

      elms = [] #: Array[Integer]
      elen = fetch_uleb128(sbuf)
      elen.times do |i|
        index = fetch_uleb128(sbuf)
        elms << index
      end
      dest.element_indices << elms
    else
      raise NotImplementedError, "element section type #{etype} is a TODO!"
    end
  end
  dest
end

.export_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 872

def self.export_section
  dest = ExportSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    nlen = fetch_uleb128(sbuf)
    name = assert_read(sbuf, nlen)
    kind_ = assert_read(sbuf, 1)
    kind = kind_[0]&.ord
    if !kind
      raise "[BUG] empty unpacked string" # guard rbs
    end

    index = fetch_uleb128(sbuf)
    dest.add_desc do |desc|
      desc.name = name
      desc.kind = kind
      desc.index = index
    end
  end

  dest
end

.fetch_insn_while_end(sbuf) ⇒ Object 



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# File 'lib/wardite/load.rb', line 798

def self.fetch_insn_while_end(sbuf)
  code = String.new("")
  loop {
    c = sbuf.read 1
    if !c
      break
    end
    code << c
    if c == "\u000b" # :end
      break
    end
  }
  code
end

.function_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 538

def self.function_section
  dest = FunctionSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    index = fetch_uleb128(sbuf)
    dest.func_indices << index
  end
  dest
end

.global_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 507

def self.global_section
  dest = GlobalSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    typeb = fetch_uleb128(sbuf)
    gtype = Op.i2type(typeb)
    mut = sbuf.read 1
    if !mut
      raise LoadError, "global section too short"
    end
    
    code = fetch_insn_while_end(sbuf)
    ops = code_body(StringIO.new(code))
    value = decode_global_expr(ops)

    global = GlobalSection::Global.new do |g|
      g.type = gtype
      g.mutable = (mut.ord == 0x01)
      g.shared = false # always
      g.value = value
    end
    dest.globals << global
  end
  dest
end

.import_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 408

def self.import_section
  dest = ImportSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    mlen = fetch_uleb128(sbuf)
    module_name = assert_read(sbuf, mlen)
    nlen = fetch_uleb128(sbuf)
    name = assert_read(sbuf, nlen)
    kind_ = assert_read(sbuf, 1)
    kind = kind_[0]&.ord
    if !kind
      raise "[BUG] empty unpacked string" # guard rbs
    end

    index = fetch_uleb128(sbuf)
    dest.add_desc do |desc|
      desc.module_name = module_name
      desc.name = name
      desc.kind = kind
      desc.sig_index = index
    end
  end

  dest
end

.load_from_buffer(buf, import_object: {}, enable_wasi: true) ⇒ Object 



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# File 'lib/wardite/load.rb', line 255

def self.load_from_buffer(buf, import_object: {}, enable_wasi: true)
  start = Time.now.to_f #: Float
  @buf = buf

  version = preamble
  sections_ = sections

  wasi_env = nil
  if enable_wasi
    require "wardite/wasi"
    wasi_env = Wardite::WasiSnapshotPreview1.new       
    import_object[:wasi_snapshot_preview1] = wasi_env
  end

  return Instance.new(import_object) do |i|
    i.version = version
    i.sections = sections_
    if enable_wasi
      i.wasi = wasi_env
    end
  end
ensure
  $stderr.puts "load_from_buffer: #{Time.now.to_f - start}" if ENV['WARITE_TRACE']
end

.memory_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 439

def self.memory_section
  dest = MemorySection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  if len != 1
    raise LoadError, "memory section has invalid size: #{len}"
  end
  len.times do |i|
    flags = fetch_uleb128(sbuf)
    min = fetch_uleb128(sbuf)

    max = nil
    if flags != 0
      max = fetch_uleb128(sbuf)
    end
    dest.limits << [min, max]
  end
  dest
end

.preamble ⇒ Object 



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# File 'lib/wardite/load.rb', line 281

def self.preamble
  asm = @buf.read 4
  if !asm
    raise LoadError, "buffer too short"
  end
  if asm != "\u0000asm"
    raise LoadError, "invalid preamble"
  end

  vstr = @buf.read(4)
  if !vstr
    raise LoadError, "buffer too short"
  end
  version = vstr.to_enum(:chars)
    .with_index
    .inject(0) {|dest, (c, i)| dest | (c.ord << i*8) }
  if version != 1
    raise LoadError, "unsupported version: #{version}"
  end
  version
end

.resolve_code(c, buf) ⇒ Object 



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# File 'lib/wardite/load.rb', line 726

def self.resolve_code(c, buf)
  ord = c.ord
  code = Op::SYMS[ord]
  if code == :fc
    lower = fetch_uleb128(buf)
    sym = Op::FC_SYMS[lower]
    namespace = Op::FC_OPERANDS[lower] || :default
    return [namespace, sym, Op.operand_of(sym)]
  end
  namespace = Op::NAMESPACES[ord] || raise("unsupported code: #{ord}")
  return [namespace, code, Op::OPERANDS[ord]]
end

.sections ⇒ Object 



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# File 'lib/wardite/load.rb', line 304

def self.sections
  sections = [] #: Array[Section]

  loop do
    byte = @buf.read(1)
    if !byte
      break
    end
    code = byte.ord

    section = case code
      when Wardite::SectionType
        type_section
      when Wardite::SectionImport
        import_section
      when Wardite::SectionFunction
        function_section
      when Wardite::SectionTable
        table_section
      when Wardite::SectionMemory
        memory_section
      when Wardite::SectionGlobal
        global_section
      when Wardite::SectionExport
        export_section
      when Wardite::SectionStart
        start_section
      when Wardite::SectionElement
        elem_section
      when Wardite::SectionCode
        code_section
      when Wardite::SectionData
        data_section
      when Wardite::Const::SectionDataCount
        data_count_section
      when Wardite::SectionCustom
        unimplemented_skip_section(code)
      else
        raise LoadError, "unknown code: #{code}(\"#{code.to_s 16}\")"
      end

    if section
      sections << section
    end
  end
  sections
end

.start_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 463

def self.start_section
  dest = StartSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  # StartSection won't use size
  func_index = fetch_uleb128(@buf)
  dest.func_index = func_index
  dest
end

.table_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 553

def self.table_section
  dest = TableSection.new
  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    code = fetch_uleb128(sbuf)
    type = Op.i2type(code)
    dest.table_types << type

    flags = fetch_uleb128(sbuf)
    min = fetch_uleb128(sbuf)
    max = nil
    if flags != 0
      max = fetch_uleb128(sbuf)
    end
    dest.table_limits << [min, max]
  end
  dest
end

.type_section ⇒ Object 



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# File 'lib/wardite/load.rb', line 353

def self.type_section
  dest = TypeSection.new

  size = fetch_uleb128(@buf)
  dest.size = size
  sbuf = StringIO.new(@buf.read(size) || raise("buffer too short"))

  len = fetch_uleb128(sbuf)
  len.times do |i|
    fncode = assert_read(sbuf, 1)
    if fncode != "\x60"
      raise LoadError, "not a function definition"
    end

    arglen = fetch_uleb128(sbuf)
    arg = [] #: Array[Symbol]
    arglen.times do
      case ty = assert_read(sbuf, 1)&.ord
      when 0x7f
        arg << :i32
      when 0x7e
        arg << :i64
      when 0x7d
        arg << :f32
      when 0x7c
        arg << :f64
      else
        raise NotImplementedError, "unsupported for now: #{ty.inspect}"
      end
    end
    dest.defined_types << arg

    retlen = fetch_uleb128(sbuf)
    ret = [] #: Array[Symbol]
    retlen.times do
      case ty = assert_read(sbuf, 1)&.ord
      when 0x7f
        ret << :i32
      when 0x7e
        ret << :i64
      when 0x7d
        ret << :f32
      when 0x7c
        ret << :f64
      else
        raise NotImplementedError, "unsupported for now: #{ty.inspect}"
      end
    end
    dest.defined_results << ret
  end

  dest
end

.unimplemented_skip_section(code) ⇒ Object 



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# File 'lib/wardite/load.rb', line 901

def self.unimplemented_skip_section(code)
  $stderr.puts "warning: unimplemented section: 0x0#{code}" if ENV['WARN_UNIMPLEMENTED_SECTION']
  size = fetch_uleb128(@buf)
  @buf.read(size)
  nil
end