288 lines
13 KiB
Haskell
288 lines
13 KiB
Haskell
-- | Writer assembler to an object file.
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module Language.Elna.RiscV.ElfWriter
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( riscv32Elf
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) where
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import Data.Word (Word8)
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import Data.ByteString (StrictByteString)
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import qualified Data.ByteString as ByteString
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import qualified Data.ByteString.Builder as ByteString.Builder
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import qualified Data.ByteString.Lazy as LazyByteString
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import Data.Vector (Vector)
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import qualified Data.Vector as Vector
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import Language.Elna.Object.ElfCoder
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( ByteOrder(..)
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, Elf32_Addr
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, Elf32_Ehdr(..)
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, Elf32_Half
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, Elf32_Word
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, Elf32_Sym(..)
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, ElfMachine(..)
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, ElfType(..)
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, ElfVersion(..)
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, ElfIdentification(..)
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, ElfClass(..)
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, ElfData(..)
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, Elf32_Shdr(..)
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, ElfSectionType(..)
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, ElfSymbolBinding(..)
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, ElfSymbolType(..)
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, Elf32_Rel(..)
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, ElfWriter(..)
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, ElfHeaderResult(..)
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, elf32Sym
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, elfHeaderSize
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, elfSectionsSize
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, stInfo
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, rInfo
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, elf32Rel
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, shfInfoLink
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, addSectionHeader
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)
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import System.IO (Handle)
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import qualified Language.Elna.Architecture.RiscV as RiscV
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import qualified Data.Text.Encoding as Text
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import Control.Monad.IO.Class (MonadIO(..))
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import Control.Monad.Trans.State (get, gets)
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import Language.Elna.RiscV.CodeGenerator (Statement(..))
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import qualified Language.Elna.Object.StringTable as StringTable
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import qualified Data.HashSet as HashSet
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import GHC.Records (HasField(..))
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data UnresolvedRelocation = UnresolvedRelocation StrictByteString Elf32_Addr Word8
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data UnresolvedRelocations = UnresolvedRelocations (Vector UnresolvedRelocation) Elf32_Word
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riscv32Elf :: Vector Statement -> Handle -> ElfWriter Elf32_Ehdr
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riscv32Elf code objectHandle = text
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>>= uncurry symrel
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>>= strtab
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>> shstrtab
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>>= riscv32Header
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where
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shstrtab :: ElfWriter Elf32_Half
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shstrtab = do
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ElfHeaderResult{..} <- ElfWriter get
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let stringTable = ".shstrtab"
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currentNamesSize = StringTable.size sectionNames
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nextHeader = Elf32_Shdr
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{ sh_type = SHT_STRTAB
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, sh_size = currentNamesSize -- Adding trailing null character.
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+ fromIntegral (succ $ ByteString.length stringTable)
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, sh_offset = elfSectionsSize sectionHeaders
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, sh_name = currentNamesSize
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, sh_link = 0
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, sh_info = 0
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, sh_flags = 0
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, sh_entsize = 0
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, sh_addralign = 1
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, sh_addr = 0
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}
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addSectionHeader stringTable nextHeader
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updatedSectionNames <- ElfWriter $ gets (StringTable.encode . getField @"sectionNames")
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liftIO $ ByteString.hPut objectHandle updatedSectionNames
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pure $ fromIntegral $ Vector.length sectionHeaders
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riscv32Header :: Elf32_Half -> ElfWriter Elf32_Ehdr
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riscv32Header shstrndx = do
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ElfHeaderResult{..} <- ElfWriter get
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pure $ Elf32_Ehdr
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{ e_version = EV_CURRENT
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, e_type = ET_REL
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, e_shstrndx = shstrndx
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, e_shoff = elfSectionsSize sectionHeaders
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, e_shnum = fromIntegral (Vector.length sectionHeaders)
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, e_shentsize = 40
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, e_phoff = 0
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, e_phnum = 0
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, e_phentsize = 32
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, e_machine = EM_RISCV
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, e_ident = ElfIdentification ELFCLASS32 ELFDATA2LSB
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, e_flags = 0x4 -- EF_RISCV_FLOAT_ABI_DOUBLE
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, e_entry = 0
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, e_ehsize = fromIntegral elfHeaderSize
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}
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takeStringZ stringTable Elf32_Sym{ st_name }
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= StringTable.index st_name stringTable
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resolveRelocation (ElfHeaderResult stringTable entries) unresolvedRelocation
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| UnresolvedRelocation symbolName offset type' <- unresolvedRelocation
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, Just entry <- Vector.findIndex ((== symbolName) . takeStringZ stringTable) entries =
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Right $ Elf32_Rel
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{ r_offset = offset
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, r_info = rInfo (fromIntegral entry) type'
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}
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| otherwise = Left unresolvedRelocation
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symtab entries = do
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ElfHeaderResult{..} <- ElfWriter get
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let encodedSymbols = LazyByteString.toStrict
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$ ByteString.Builder.toLazyByteString
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$ foldMap (elf32Sym LSB) entries
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symHeader = Elf32_Shdr
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{ sh_type = SHT_SYMTAB
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, sh_size = fromIntegral $ ByteString.length encodedSymbols
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, sh_offset = elfSectionsSize sectionHeaders
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, sh_name = StringTable.size sectionNames
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, sh_link = fromIntegral $ Vector.length sectionHeaders + 2
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, sh_info = 1
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, sh_flags = 0
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, sh_entsize = 16
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, sh_addralign = 4
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, sh_addr = 0
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}
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liftIO $ ByteString.hPut objectHandle encodedSymbols
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addSectionHeader ".symtab" symHeader
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pure $ fromIntegral $ Vector.length sectionHeaders
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symrel symbols relocations = do
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let UnresolvedRelocations relocationList index = relocations
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ElfHeaderResult stringTable entries = symbols
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sectionHeadersLength <- symtab entries
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ElfHeaderResult{..} <- ElfWriter get
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let encodedRelocations = LazyByteString.toStrict
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$ ByteString.Builder.toLazyByteString
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$ Vector.foldMap (either (const mempty) (elf32Rel LSB))
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$ resolveRelocation symbols <$> relocationList
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relHeader = Elf32_Shdr
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{ sh_type = SHT_REL
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, sh_size = fromIntegral $ ByteString.length encodedRelocations
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, sh_offset = elfSectionsSize sectionHeaders
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, sh_name = StringTable.size sectionNames
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, sh_link = sectionHeadersLength
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, sh_info = index
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, sh_flags = shfInfoLink
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, sh_entsize = 8
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, sh_addralign = 4
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, sh_addr = 0
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}
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liftIO $ ByteString.hPut objectHandle encodedRelocations
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addSectionHeader ".rel.text" relHeader
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pure stringTable
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strtab stringTable = do
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ElfHeaderResult{..} <- ElfWriter get
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let strHeader = Elf32_Shdr
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{ sh_type = SHT_STRTAB
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, sh_size = StringTable.size stringTable
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, sh_offset = elfSectionsSize sectionHeaders
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, sh_name = StringTable.size sectionNames
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, sh_link = 0
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, sh_info = 0
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, sh_flags = 0
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, sh_entsize = 0
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, sh_addralign = 1
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, sh_addr = 0
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}
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liftIO $ ByteString.hPut objectHandle $ StringTable.encode stringTable
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addSectionHeader ".strtab" strHeader
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text = do
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ElfHeaderResult{..} <- ElfWriter get
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let textTabIndex = fromIntegral $ Vector.length sectionHeaders
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initialHeaders = ElfHeaderResult mempty
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$ Vector.singleton
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$ Elf32_Sym
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{ st_value = 0
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, st_size = 0
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, st_shndx = 0
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, st_other = 0
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, st_name = 0
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, st_info = 0
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}
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(encoded, updatedRelocations, symbols, definitions) =
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encodeAsm textTabIndex (mempty, Vector.empty, initialHeaders, HashSet.empty) code
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filterPredicate :: StrictByteString -> Bool
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filterPredicate = not
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. (`StringTable.elem` getField @"sectionNames" symbols)
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symbolResult = HashSet.foldl' encodeEmptyDefinitions symbols
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$ HashSet.filter filterPredicate definitions
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size = fromIntegral $ LazyByteString.length encoded
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newHeader = Elf32_Shdr
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{ sh_type = SHT_PROGBITS
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, sh_size = size
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, sh_offset = elfSectionsSize sectionHeaders
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, sh_name = StringTable.size sectionNames
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, sh_link = 0
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, sh_info = 0
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, sh_flags = 0b110
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, sh_entsize = 0
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, sh_addralign = 4
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, sh_addr = 0
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}
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liftIO $ ByteString.hPut objectHandle $ LazyByteString.toStrict encoded
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addSectionHeader ".text" newHeader
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pure (symbolResult, UnresolvedRelocations updatedRelocations $ fromIntegral $ Vector.length sectionHeaders)
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encodeEmptyDefinitions (ElfHeaderResult names entries) definition =
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let nextEntry = Elf32_Sym
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{ st_value = 0
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, st_size = 0
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, st_shndx = 0
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, st_other = 0
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, st_name = StringTable.size names
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, st_info = stInfo STB_GLOBAL STT_FUNC
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}
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in ElfHeaderResult (StringTable.append definition names)
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$ Vector.snoc entries nextEntry
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encodeAsm shndx (encoded, relocations, ElfHeaderResult names symbols, definitions) instructions
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| Just (instruction, rest) <- Vector.uncons instructions =
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case instruction of
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Instruction _ ->
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let (encoded', relocations', rest', definitions') =
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encodeInstructions (encoded, relocations, instructions, definitions)
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in encodeAsm shndx (encoded', relocations', ElfHeaderResult names symbols, definitions') rest'
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JumpLabel labelName _ ->
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let (encoded', relocations', rest', definitions') =
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encodeInstructions (encoded, relocations, rest, definitions)
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newEntry = Elf32_Sym
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{ st_value = fromIntegral $ LazyByteString.length encoded
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, st_size = fromIntegral $ LazyByteString.length encoded'
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, st_shndx = shndx
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, st_other = 0
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, st_name = StringTable.size names
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, st_info = stInfo STB_GLOBAL STT_FUNC
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}
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result =
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( encoded'
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, relocations'
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, ElfHeaderResult (StringTable.append (Text.encodeUtf8 labelName) names)
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$ Vector.snoc symbols newEntry
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, definitions'
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)
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in encodeAsm shndx result rest'
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| otherwise = (encoded, relocations, ElfHeaderResult names symbols, definitions)
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encodeInstructions (encoded, relocations, instructions, definitions)
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| Just (Instruction instruction, rest) <- Vector.uncons instructions =
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let offset = fromIntegral $ LazyByteString.length encoded
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unresolvedRelocation = case instruction of
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RiscV.RelocatableInstruction _ instructionType
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| RiscV.RHigher20 _ symbolName <- instructionType
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-> Just -- R_RISCV_HI20
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$ UnresolvedRelocation (Text.encodeUtf8 symbolName) offset 26
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| RiscV.RLower12I _ _ _ symbolName <- instructionType
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-> Just -- R_RISCV_LO12_I
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$ UnresolvedRelocation (Text.encodeUtf8 symbolName) offset 27
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| RiscV.RLower12S symbolName _ _ _ <- instructionType
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-> Just -- R_RISCV_LO12_S
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$ UnresolvedRelocation (Text.encodeUtf8 symbolName) offset 28
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| RiscV.RBranch symbolName _ _ _ <- instructionType
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-> Just -- R_RISCV_BRANCH
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$ UnresolvedRelocation (Text.encodeUtf8 symbolName) offset 16
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| RiscV.RJal _ symbolName <- instructionType
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-> Just -- R_RISCV_JAL
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$ UnresolvedRelocation (Text.encodeUtf8 symbolName) offset 17
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RiscV.CallInstruction symbolName
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-> Just -- R_RISCV_CALL_PLT
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$ UnresolvedRelocation (Text.encodeUtf8 symbolName) offset 19
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RiscV.BaseInstruction _ _ -> Nothing
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chunk = ByteString.Builder.toLazyByteString
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$ RiscV.instruction instruction
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result =
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( encoded <> chunk
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, maybe relocations (Vector.snoc relocations) unresolvedRelocation
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, rest
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, addDefinition unresolvedRelocation definitions
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)
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in encodeInstructions result
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| otherwise = (encoded, relocations, instructions, definitions)
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addDefinition (Just (UnresolvedRelocation symbolName _ _)) =
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HashSet.insert symbolName
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addDefinition Nothing = id
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