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-- | Writer assembler to an object file.
module Language.Elna.PrinterWriter
( riscv32Elf
, riscv32Header
) where
import Data.ByteString (ByteString)
import qualified Data.ByteString as ByteString
import qualified Data.ByteString.Builder as ByteString.Builder
import qualified Data.ByteString.Lazy as LazyByteString
import Data.Vector (Vector)
import qualified Data.Vector as Vector
import Language.Elna.Object.Elf
( ByteOrder(..)
, Elf32_Ehdr(..)
, Elf32_Half
, Elf32_Sym(..)
, ElfMachine(..)
, ElfType(..)
, ElfVersion(..)
, ElfIdentification(..)
, ElfClass(..)
, ElfData(..)
, Elf32_Shdr(..)
, ElfSectionType(..)
, ElfSymbolBinding(..)
, ElfSymbolType(..)
, elf32Sym
, elfHeaderSize
, elfSectionsSize
, stInfo
)
import System.IO (Handle)
import qualified Language.Elna.Architecture.RiscV as RiscV
data ElfHeaderResult a = ElfHeaderResult ByteString (Vector a)
riscv32Elf :: Vector RiscV.Instruction -> Handle -> IO (Vector Elf32_Shdr)
riscv32Elf code objectHandle =
let zeroHeader = Elf32_Shdr
{ sh_type = SHT_NULL
, sh_size = 0
, sh_offset = 0
, sh_name = 0
, sh_link = 0
, sh_info = 0
, sh_flags = 0
, sh_entsize = 0
, sh_addralign = 0
, sh_addr = 0
}
in text (ElfHeaderResult "\0" $ Vector.singleton zeroHeader)
>>= shstrtab
>>= finalize
where
finalize (ElfHeaderResult _ headers) = pure headers
shstrtab (ElfHeaderResult names headers) = do
let stringTable = names <> ".shstrtab\0"
nextHeader = Elf32_Shdr
{ sh_type = SHT_STRTAB
, sh_size = fromIntegral $ ByteString.length stringTable
, sh_offset = elfSectionsSize headers
, sh_name = fromIntegral $ ByteString.length names
, sh_link = 0
, sh_info = 0
, sh_flags = 0
, sh_entsize = 0
, sh_addralign = 0
, sh_addr = 0
}
ByteString.hPut objectHandle stringTable
pure $ ElfHeaderResult stringTable
$ Vector.snoc headers nextHeader
strtab stringTable (ElfHeaderResult names headers) = do
let newHeader = Elf32_Shdr
{ sh_type = SHT_STRTAB
, sh_size = fromIntegral $ ByteString.length stringTable
, sh_offset = elfSectionsSize headers
, sh_name = fromIntegral $ ByteString.length names
, sh_link = 0
, sh_info = 0
, sh_flags = 0
, sh_entsize = 0
, sh_addralign = 0
, sh_addr = 0
}
ByteString.hPut objectHandle stringTable
pure $ ElfHeaderResult (names <> ".strtab\0")
$ Vector.snoc headers newHeader
symtab strtabIndex entries (ElfHeaderResult names headers) = do
let encoded = LazyByteString.toStrict
$ ByteString.Builder.toLazyByteString
$ foldMap (elf32Sym LSB) entries
newHeader = Elf32_Shdr
{ sh_type = SHT_SYMTAB
, sh_size = fromIntegral $ ByteString.length encoded
, sh_offset = elfSectionsSize headers
, sh_name = fromIntegral $ ByteString.length names
, sh_link = strtabIndex
, sh_info = 1
, sh_flags = 0
, sh_entsize = 16
, sh_addralign = 0
, sh_addr = 0
}
ByteString.hPut objectHandle encoded
pure $ ElfHeaderResult (names <> ".symtab\0")
$ Vector.snoc headers newHeader
text (ElfHeaderResult names headers) = do
let textTabIndex = fromIntegral $ Vector.length headers
strtabIndex = fromIntegral $ textTabIndex + 2
ElfHeaderResult stringTable entries <- symbolEntry textTabIndex code
$ ElfHeaderResult "\0"
$ Vector.singleton
$ Elf32_Sym
{ st_value = 0
, st_size = 0
, st_shndx = 0
, st_other = 0
, st_name = 0
, st_info = 0
}
let newHeader = Elf32_Shdr
{ sh_type = SHT_PROGBITS
, sh_size = fromIntegral $ foldr ((+) . st_size) 0 entries
, sh_offset = elfSectionsSize headers
, sh_name = fromIntegral $ ByteString.length names
, sh_link = 0
, sh_info = 0
, sh_flags = 0b110
, sh_entsize = 0
, sh_addralign = 0
, sh_addr = 0
}
newResult = ElfHeaderResult (names <> ".text\0")
$ Vector.snoc headers newHeader
symtab strtabIndex entries newResult
>>= strtab stringTable
symbolEntry :: Elf32_Half -> Vector RiscV.Instruction -> ElfHeaderResult Elf32_Sym -> IO (ElfHeaderResult Elf32_Sym)
symbolEntry shndx instructions (ElfHeaderResult names entries) = do
let encoded = LazyByteString.toStrict
$ ByteString.Builder.toLazyByteString
$ foldMap RiscV.instruction instructions
newEntry = Elf32_Sym
{ st_value = 0
, st_size = fromIntegral $ ByteString.length encoded
, st_shndx = shndx
, st_other = 0
, st_name = fromIntegral $ ByteString.length names
, st_info = stInfo STB_GLOBAL STT_FUNC
}
ByteString.hPut objectHandle encoded
pure $ ElfHeaderResult (names <> "_start\0")
$ Vector.snoc entries newEntry
riscv32Header :: Elf32_Ehdr
riscv32Header = Elf32_Ehdr
{ e_version = EV_CURRENT
, e_type = ET_REL
, e_shstrndx = 2 -- String table. SHN_UNDEF
, e_shoff = 0
, e_shnum = 0
, e_shentsize = 40
, e_phoff = 0
, e_phnum = 0
, e_phentsize = 32
, e_machine = EM_RISCV
, e_ident = ElfIdentification ELFCLASS32 ELFDATA2LSB
, e_flags = 0x4 -- EF_RISCV_FLOAT_ABI_DOUBLE
, e_entry = 0
, e_ehsize = fromIntegral elfHeaderSize
}
|
