[Git][ghc/ghc][wip/fendor/ifacetype-deduplication] 3 commits: Add deduplication table for `IfaceType`
Hannes Siebenhandl (@fendor)
gitlab at gitlab.haskell.org
Wed May 15 08:32:30 UTC 2024
Hannes Siebenhandl pushed to branch wip/fendor/ifacetype-deduplication at Glasgow Haskell Compiler / GHC
Commits:
bb74e328 by Fendor at 2024-05-15T09:23:44+02:00
Add deduplication table for `IfaceType`
The type `IfaceType` is a highly redundant, tree-like data structure.
While benchmarking, we realised that the high redundancy of `IfaceType`
causes high memory consumption in GHCi sessions when byte code is
embedded into the `.hi` file via `-fwrite-if-simplified-core` or
`-fbyte-code-and-object-code`.
Loading such `.hi` files from disk introduces many duplicates of
memory expensive values in `IfaceType`, such as `IfaceTyCon`,
`IfaceTyConApp`, `IA_Arg` and many more.
We improve the memory behaviour of GHCi by adding an additional
deduplication table for `IfaceType` to the serialisation of `ModIface`,
similar to how we deduplicate `Name`s and `FastString`s.
When reading the interface file back, the table allows us to automatically
share identical values of `IfaceType`.
To provide some numbers, we evaluated this patch on the agda code base.
We loaded the full library from the `.hi` files, which contained the
embedded core expressions (`-fwrite-if-simplified-core`).
Before this patch:
* Load time: 11.7 s, 2.5 GB maximum residency.
After this patch:
* Load time: 7.3 s, 1.7 GB maximum residency.
This deduplication has the beneficial side effect to additionally reduce
the size of the on-disk interface files tremendously.
For example, on agda, we reduce the size of `.hi` files (with
`-fwrite-if-simplified-core`):
* Before: 101 MB on disk
* Now: 24 MB on disk
This has even a beneficial side effect on the cabal store. We reduce the
size of the store on disk:
* Before: 341 MB on disk
* Now: 310 MB on disk
Note, none of the dependencies have been compiled with
`-fwrite-if-simplified-core`, but `IfaceType` occurs in multiple
locations in a `ModIface`.
We also add IfaceType deduplication table to .hie serialisation and
refactor .hie file serialisation to use the same infrastrucutre as
`putWithTables`.
Bump haddock submodule to accomodate for changes to the deduplication
table layout and binary interface.
- - - - -
e0a49989 by Fendor at 2024-05-15T09:48:58+02:00
Add run-time configurability of `.hi` file compression
Introduce the flag `-fwrite-if-compression=<n>` which allows to
configure the compression level of writing .hi files.
The motivation is that some deduplication operations are too expensive
for the average use case. Hence, we introduce multiple compression
levels with variable impact on performance, but still reduce the
memory residency and `.hi` file size on disk considerably.
We introduce three compression levels:
* `1`: `Normal` mode. This is the least amount of compression.
It deduplicates only `Name` and `FastString`s, and is naturally the
fastest compression mode.
* `2`: `Safe` mode. It has a noticeable impact on .hi file size and is
marginally slower than `Normal` mode. In general, it should be safe to
always use `Safe` mode.
* `3`: `Full` deduplication mode. Deduplicate as much as we can,
resulting in minimal .hi files, but at the cost of additional
compilation time.
Reading .hi files doesn't need to know the initial compression level,
and can always deserialise a `ModIface`, as we write out a byte that
indicates the next value has been deduplicated.
This allows users to experiment with different compression levels for
packages, without recompilation of dependencies.
Note, the deduplication also has an additional side effect of reduced
memory consumption to implicit sharing of deduplicated elements.
See https://gitlab.haskell.org/ghc/ghc/-/issues/24540 for example where
that matters.
-------------------------
Metric Decrease:
MultiLayerModulesDefsGhciWithCore
T16875
T21839c
T24471
hard_hole_fits
libdir
-------------------------
- - - - -
63c71dc4 by Matthew Pickering at 2024-05-15T09:48:58+02:00
Introduce regression tests for `.hi` file sizes
Add regression tests to track how `-fwrite-if-compression` levels affect
the size of `.hi` files.
- - - - -
20 changed files:
- compiler/GHC/Driver/DynFlags.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Iface/Binary.hs
- compiler/GHC/Iface/Ext/Binary.hs
- compiler/GHC/Iface/Load.hs
- compiler/GHC/Iface/Recomp/Binary.hs
- compiler/GHC/Iface/Type.hs
- compiler/GHC/StgToJS/Object.hs
- compiler/GHC/Utils/Binary.hs
- docs/users_guide/using-optimisation.rst
- + testsuite/tests/iface/IfaceSharingIfaceType.hs
- + testsuite/tests/iface/IfaceSharingName.hs
- + testsuite/tests/iface/Lib.hs
- + testsuite/tests/iface/Makefile
- + testsuite/tests/iface/all.T
- + testsuite/tests/iface/if_faststring.hs
- + testsuite/tests/iface/if_ifacetype.hs
- + testsuite/tests/iface/if_name.hs
- utils/haddock
Changes:
=====================================
compiler/GHC/Driver/DynFlags.hs
=====================================
@@ -207,6 +207,7 @@ data DynFlags = DynFlags {
dmdUnboxWidth :: !Int, -- ^ Whether DmdAnal should optimistically put an
-- Unboxed demand on returned products with at most
-- this number of fields
+ ifCompression :: Int,
specConstrThreshold :: Maybe Int, -- ^ Threshold for SpecConstr
specConstrCount :: Maybe Int, -- ^ Max number of specialisations for any one function
specConstrRecursive :: Int, -- ^ Max number of specialisations for recursive types
@@ -546,6 +547,7 @@ defaultDynFlags mySettings =
maxPmCheckModels = 30,
simplTickFactor = 100,
dmdUnboxWidth = 3, -- Default: Assume an unboxed demand on function bodies returning a triple
+ ifCompression = 2, -- Default: Apply safe compressions
specConstrThreshold = Just 2000,
specConstrCount = Just 3,
specConstrRecursive = 3,
=====================================
compiler/GHC/Driver/Main.hs
=====================================
@@ -163,7 +163,7 @@ import GHC.JS.Syntax
import GHC.IfaceToCore ( typecheckIface, typecheckWholeCoreBindings )
-import GHC.Iface.Load ( ifaceStats, writeIface )
+import GHC.Iface.Load ( ifaceStats, writeIface, flagsToIfCompression )
import GHC.Iface.Make
import GHC.Iface.Recomp
import GHC.Iface.Tidy
@@ -1207,7 +1207,7 @@ hscMaybeWriteIface logger dflags is_simple iface old_iface mod_location = do
withTiming logger
(text "WriteIface"<+>brackets (text iface_name))
(const ())
- (writeIface logger profile iface_name iface)
+ (writeIface logger profile (flagsToIfCompression dflags) iface_name iface)
if (write_interface || force_write_interface) then do
=====================================
compiler/GHC/Driver/Session.hs
=====================================
@@ -1718,6 +1718,9 @@ dynamic_flags_deps = [
, make_ord_flag defFlag "fno-refinement-level-hole-fits"
(noArg (\d -> d { refLevelHoleFits = Nothing }))
+ , make_ord_flag defFlag "fwrite-if-compression"
+ (intSuffix (\n d -> d { ifCompression = n }))
+
, make_dep_flag defGhcFlag "fllvm-pass-vectors-in-regs"
(noArg id)
"vectors registers are now passed in registers by default."
=====================================
compiler/GHC/Iface/Binary.hs
=====================================
@@ -14,6 +14,7 @@ module GHC.Iface.Binary (
writeBinIface,
readBinIface,
readBinIfaceHeader,
+ CompressionIFace(..),
getSymtabName,
CheckHiWay(..),
TraceBinIFace(..),
@@ -25,6 +26,8 @@ module GHC.Iface.Binary (
putName,
putSymbolTable,
BinSymbolTable(..),
+ initWriteIfaceType, initReadIfaceTypeTable,
+ putAllTables,
) where
import GHC.Prelude
@@ -46,14 +49,19 @@ import GHC.Types.SrcLoc
import GHC.Platform
import GHC.Settings.Constants
import GHC.Utils.Fingerprint
+import GHC.Iface.Type (IfaceType(..), getIfaceType, putIfaceType, ifaceTypeSharedByte)
+import Control.Monad
import Data.Array
import Data.Array.IO
import Data.Array.Unsafe
import Data.Char
-import Data.Word
import Data.IORef
-import Control.Monad
+import Data.Map.Strict (Map)
+import Data.Word
+import System.IO.Unsafe
+import Data.Typeable (Typeable)
+
-- ---------------------------------------------------------------------------
-- Reading and writing binary interface files
@@ -66,6 +74,30 @@ data TraceBinIFace
= TraceBinIFace (SDoc -> IO ())
| QuietBinIFace
+-- | The compression/deduplication level of 'ModIface' files.
+--
+-- A 'ModIface' contains many duplicated symbols and names. To keep interface
+-- files small, we deduplicate them during serialisation.
+-- It is impossible to write an interface file with *no* compression/deduplication.
+--
+-- We support different levels of compression/deduplication, with different
+-- trade-offs for run-time performance and memory usage.
+-- If you don't have any specific requirements, then 'SafeExtraCompression' is a good default.
+data CompressionIFace
+ = NormalCompression
+ -- ^ Perform the normal compression operations,
+ -- such as deduplicating 'Name's and 'FastString's
+ | SafeExtraCompression
+ -- ^ Perform some extra compression steps that have minimal impact
+ -- on the run-time of 'ghc'.
+ --
+ -- This reduces the size of '.hi' files significantly in some cases
+ -- and reduces overall memory usage in certain scenarios.
+ | MaximumCompression
+ -- ^ Try to compress as much as possible.
+ --
+ -- Yields the smallest '.hi' files but at the cost of additional run-time.
+
-- | Read an interface file header, checking the magic number, version, and
-- way. Returns the hash of the source file and a BinHandle which points at the
-- start of the rest of the interface file data.
@@ -158,30 +190,43 @@ getWithUserData name_cache bh = do
-- Reading names has the side effect of adding them into the given NameCache.
getTables :: NameCache -> ReadBinHandle -> IO ReadBinHandle
getTables name_cache bh = do
+ bhRef <- newIORef (error "used too soon")
+ -- It is important this is passed to 'getTable'
+ -- See Note [Lazy ReaderUserData during IfaceType serialisation]
+ ud <- unsafeInterleaveIO (readIORef bhRef)
+
fsReaderTable <- initFastStringReaderTable
nameReaderTable <- initNameReaderTable name_cache
-
-
- -- The order of these deserialisation matters!
- --
- -- See Note [Order of deduplication tables during iface binary serialisation] for details.
- fsTable <- Binary.forwardGet bh (getTable fsReaderTable bh)
- let
- fsReader = mkReaderFromTable fsReaderTable fsTable
- bhFs = addReaderToUserData (mkSomeBinaryReader fsReader) bh
-
- nameTable <- Binary.forwardGet bh (getTable nameReaderTable bhFs)
- let
- nameReader = mkReaderFromTable nameReaderTable nameTable
- bhName = addReaderToUserData (mkSomeBinaryReader nameReader) bhFs
-
- pure bhName
+ ifaceTypeReaderTable <- initReadIfaceTypeTable ud
+
+ let -- For any 'ReaderTable', we decode the table that is found at the location
+ -- the forward reference points to.
+ -- After decoding the table, we create a 'BinaryReader' and immediately
+ -- add it to the 'ReaderUserData' of 'ReadBinHandle'.
+ decodeReaderTable :: Typeable a => ReaderTable a -> ReadBinHandle -> IO ReadBinHandle
+ decodeReaderTable tbl bh0 = do
+ table <- Binary.forwardGet bh (getTable tbl bh0)
+ let binaryReader = mkReaderFromTable tbl table
+ pure $ addReaderToUserData binaryReader bh0
+
+ -- Decode all the tables and populate the 'ReaderUserData'.
+ bhFinal <- foldM (\bh0 act -> act bh0) bh
+ -- The order of these deserialisation matters!
+ --
+ -- See Note [Order of deduplication tables during iface binary serialisation] for details.
+ [ decodeReaderTable fsReaderTable
+ , decodeReaderTable nameReaderTable
+ , decodeReaderTable ifaceTypeReaderTable
+ ]
+
+ writeIORef bhRef (getReaderUserData bhFinal)
+ pure bhFinal
-- | Write an interface file.
--
-- See Note [Deduplication during iface binary serialisation] for details.
-writeBinIface :: Profile -> TraceBinIFace -> FilePath -> ModIface -> IO ()
-writeBinIface profile traceBinIface hi_path mod_iface = do
+writeBinIface :: Profile -> TraceBinIFace -> CompressionIFace -> FilePath -> ModIface -> IO ()
+writeBinIface profile traceBinIface compressionLevel hi_path mod_iface = do
bh <- openBinMem initBinMemSize
let platform = profilePlatform profile
put_ bh (binaryInterfaceMagic platform)
@@ -195,7 +240,7 @@ writeBinIface profile traceBinIface hi_path mod_iface = do
extFields_p_p <- tellBinWriter bh
put_ bh extFields_p_p
- putWithUserData traceBinIface bh mod_iface
+ putWithUserData traceBinIface compressionLevel bh mod_iface
extFields_p <- tellBinWriter bh
putAt bh extFields_p_p extFields_p
@@ -209,9 +254,9 @@ writeBinIface profile traceBinIface hi_path mod_iface = do
-- is necessary if you want to serialise Names or FastStrings.
-- It also writes a symbol table and the dictionary.
-- This segment should be read using `getWithUserData`.
-putWithUserData :: Binary a => TraceBinIFace -> WriteBinHandle -> a -> IO ()
-putWithUserData traceBinIface bh payload = do
- (name_count, fs_count, _b) <- putWithTables bh (\bh' -> put bh' payload)
+putWithUserData :: Binary a => TraceBinIFace -> CompressionIFace -> WriteBinHandle -> a -> IO ()
+putWithUserData traceBinIface compressionLevel bh payload = do
+ (name_count, fs_count, ifacetype_count, _b) <- putWithTables compressionLevel bh (\bh' -> put bh' payload)
case traceBinIface of
QuietBinIFace -> return ()
@@ -220,25 +265,30 @@ putWithUserData traceBinIface bh payload = do
<+> text "Names")
printer (text "writeBinIface:" <+> int fs_count
<+> text "dict entries")
+ printer (text "writeBinIface:" <+> int ifacetype_count
+ <+> text "dict entries")
--- | Write name/symbol tables
+-- | Write name/symbol/ifacetype tables
--
--- 1. setup the given BinHandle with Name/FastString table handling
+-- 1. setup the given BinHandle with Name/FastString/IfaceType table handling
-- 2. write the following
-- - FastString table pointer
-- - Name table pointer
+-- - IfaceType table pointer
-- - payload
+-- - IfaceType table
-- - Name table
-- - FastString table
--
--- It returns (number of names, number of FastStrings, payload write result)
+-- It returns (number of names, number of FastStrings, number of IfaceTypes, payload write result)
--
-- See Note [Order of deduplication tables during iface binary serialisation]
-putWithTables :: WriteBinHandle -> (WriteBinHandle -> IO b) -> IO (Int, Int, b)
-putWithTables bh' put_payload = do
+putWithTables :: CompressionIFace -> WriteBinHandle -> (WriteBinHandle -> IO b) -> IO (Int, Int, Int, b)
+putWithTables compressionLevel bh' put_payload = do
-- Initialise deduplicating tables.
(fast_wt, fsWriter) <- initFastStringWriterTable
(name_wt, nameWriter) <- initNameWriterTable
+ (ifaceType_wt, ifaceTypeWriter) <- initWriteIfaceType compressionLevel
-- Initialise the 'WriterUserData'.
let writerUserData = mkWriterUserData
@@ -250,25 +300,32 @@ putWithTables bh' put_payload = do
--
-- See Note [Binary UserData]
, mkSomeBinaryWriter @BindingName $ mkWriter (\bh name -> putEntry nameWriter bh (getBindingName name))
+ , mkSomeBinaryWriter @IfaceType ifaceTypeWriter
]
let bh = setWriterUserData bh' writerUserData
- (fs_count : name_count : _, r) <-
+ ([fs_count, name_count, ifacetype_count] , r) <-
-- The order of these entries matters!
--
-- See Note [Order of deduplication tables during iface binary serialisation] for details.
- putAllTables bh [fast_wt, name_wt] $ do
+ putAllTables bh [fast_wt, name_wt, ifaceType_wt] $ do
put_payload bh
- return (name_count, fs_count, r)
- where
- putAllTables _ [] act = do
- a <- act
- pure ([], a)
- putAllTables bh (x : xs) act = do
- (r, (res, a)) <- forwardPut bh (const $ putTable x bh) $ do
- putAllTables bh xs act
- pure (r : res, a)
+ return (name_count, fs_count, ifacetype_count, r)
+
+-- | Write all deduplication tables to disk after serialising the
+-- main payload.
+--
+-- Writes forward pointers to the deduplication tables before writing the payload
+-- to allow deserialisation *before* the payload is read again.
+putAllTables :: WriteBinHandle -> [WriterTable] -> IO b -> IO ([Int], b)
+putAllTables _ [] act = do
+ a <- act
+ pure ([], a)
+putAllTables bh (x : xs) act = do
+ (r, (res, a)) <- forwardPut bh (const $ putTable x bh) $ do
+ putAllTables bh xs act
+ pure (r : res, a)
-- | Initial ram buffer to allocate for writing interface files
initBinMemSize :: Int
@@ -445,11 +502,87 @@ Here, a visualisation of the table structure we currently have (ignoring 'Extens
-}
+{-
+Note [Lazy ReaderUserData during IfaceType serialisation]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Serialising recursive data types, such as 'IfaceType', requires some trickery
+to inject the deduplication table at the right moment.
+
+When we serialise a value of 'IfaceType', we might encounter new 'IfaceType' values.
+For example, 'IfaceAppTy' has an 'IfaceType' field, which we want to deduplicate as well.
+Thus, when we serialise an 'IfaceType', we might add new 'IfaceType's to the 'GenericSymbolTable'
+(i.e., the deduplication table). These 'IfaceType's are then subsequently also serialised to disk,
+and uncover new 'IfaceType' values, etc...
+In other words, when we serialise an 'IfaceType' we write it out using a post-order traversal.
+See 'putGenericSymbolTable' for the implementation.
+
+Now, when we deserialise the deduplication table, reading the first element of the deduplication table
+will fail, as deserialisation requires that we read the child elements first. Remember, we wrote them to disk
+using a post-order traversal.
+To make this work, we therefore use 'lazyGet'' to lazily read the parent 'IfaceType', but delay the actual
+deserialisation. We just assume that once you need to force a value, the deduplication table for 'IfaceType'
+will be available.
+
+That's where 'bhRef' comes into play:
+
+@
+ bhRef <- newIORef (error "used too soon")
+ ud <- unsafeInterleaveIO (readIORef bhRef)
+ ...
+ ifaceTypeReaderTable <- initReadIfaceTypeTable ud
+ ...
+ writeIORef bhRef (getReaderUserData bhFinal)
+@
+
+'ud' is the 'ReaderUserData' that will eventually contain the deduplication table for 'IfaceType'.
+As deserialisation of the 'IfaceType' needs the deduplication table, we provide a
+promise that it will exist in the future (represented by @unsafeInterleaveIO (readIORef bhRef)@).
+We pass 'ud' to 'initReadIfaceTypeTable', so the deserialisation will use the promised deduplication table.
+
+Once we have "read" the deduplication table, it will be available in 'bhFinal', and we fulfill the promise
+that the deduplication table for 'IfaceType' exists when forced.
+-}
-- -----------------------------------------------------------------------------
-- The symbol table
--
+initReadIfaceTypeTable :: ReaderUserData -> IO (ReaderTable IfaceType)
+initReadIfaceTypeTable ud = do
+ pure $
+ ReaderTable
+ { getTable = getGenericSymbolTable (\bh -> lazyGet' getIfaceType (setReaderUserData bh ud))
+ , mkReaderFromTable = \tbl -> mkReader (getGenericSymtab tbl)
+ }
+
+initWriteIfaceType :: CompressionIFace -> IO (WriterTable, BinaryWriter IfaceType)
+initWriteIfaceType compressionLevel = do
+ sym_tab <- initGenericSymbolTable @(Map IfaceType)
+ pure
+ ( WriterTable
+ { putTable = putGenericSymbolTable sym_tab (lazyPut' putIfaceType)
+ }
+ , mkWriter $ ifaceWriter sym_tab
+ )
+ where
+ ifaceWriter sym_tab = case compressionLevel of
+ NormalCompression -> literalIfaceTypeSerialiser
+ SafeExtraCompression -> ifaceTyConAppSerialiser sym_tab
+ MaximumCompression -> fullIfaceTypeSerialiser sym_tab
+
+ ifaceTyConAppSerialiser sym_tab bh ty = case ty of
+ IfaceTyConApp {} -> do
+ put_ bh ifaceTypeSharedByte
+ putGenericSymTab sym_tab bh ty
+ _ -> putIfaceType bh ty
+
+
+ fullIfaceTypeSerialiser sym_tab bh ty = do
+ put_ bh ifaceTypeSharedByte
+ putGenericSymTab sym_tab bh ty
+
+ literalIfaceTypeSerialiser = putIfaceType
+
initNameReaderTable :: NameCache -> IO (ReaderTable Name)
initNameReaderTable cache = do
=====================================
compiler/GHC/Iface/Ext/Binary.hs
=====================================
@@ -15,20 +15,24 @@ module GHC.Iface.Ext.Binary
)
where
+import GHC.Prelude
+
+import GHC.Builtin.Utils
import GHC.Settings.Utils ( maybeRead )
import GHC.Settings.Config ( cProjectVersion )
-import GHC.Prelude
import GHC.Utils.Binary
import GHC.Data.FastMutInt
import GHC.Data.FastString ( FastString )
+import GHC.Iface.Ext.Types
+import GHC.Iface.Binary ( putAllTables )
import GHC.Types.Name
import GHC.Types.Name.Cache
-import GHC.Utils.Outputable
-import GHC.Utils.Panic
-import GHC.Builtin.Utils
import GHC.Types.SrcLoc as SrcLoc
import GHC.Types.Unique
import GHC.Types.Unique.FM
+import qualified GHC.Utils.Binary as Binary
+import GHC.Utils.Outputable
+import GHC.Utils.Panic
import qualified Data.Array as A
import qualified Data.Array.IO as A
@@ -38,22 +42,15 @@ import Data.ByteString ( ByteString )
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as BSC
import Data.Word ( Word8, Word32 )
-import Control.Monad ( replicateM, when, forM_ )
+import Control.Monad ( replicateM, when, forM_, foldM )
import System.Directory ( createDirectoryIfMissing )
import System.FilePath ( takeDirectory )
-import GHC.Iface.Ext.Types
-
data HieSymbolTable = HieSymbolTable
{ hie_symtab_next :: !FastMutInt
, hie_symtab_map :: !(IORef (UniqFM Name (Int, HieName)))
}
-data HieDictionary = HieDictionary
- { hie_dict_next :: !FastMutInt -- The next index to use
- , hie_dict_map :: !(IORef (UniqFM FastString (Int,FastString))) -- indexed by FastString
- }
-
initBinMemSize :: Int
initBinMemSize = 1024*1024
@@ -73,7 +70,7 @@ putBinLine bh xs = do
putByte bh 10 -- newline char
-- | Write a `HieFile` to the given `FilePath`, with a proper header and
--- symbol tables for `Name`s and `FastString`s
+-- symbol tables for `Name`s and `FastString`s.
writeHieFile :: FilePath -> HieFile -> IO ()
writeHieFile hie_file_path hiefile = do
bh0 <- openBinMem initBinMemSize
@@ -84,58 +81,56 @@ writeHieFile hie_file_path hiefile = do
putBinLine bh0 $ BSC.pack $ show hieVersion
putBinLine bh0 $ ghcVersion
- -- remember where the dictionary pointer will go
- dict_p_p <- tellBinWriter bh0
- put_ bh0 dict_p_p
+ (fs_tbl, fs_w) <- initFastStringWriterTable
+ (name_tbl, name_w) <- initWriteNameTable
- -- remember where the symbol table pointer will go
- symtab_p_p <- tellBinWriter bh0
- put_ bh0 symtab_p_p
+ let bh = setWriterUserData bh0 $ mkWriterUserData
+ [ mkSomeBinaryWriter @Name name_w
+ , mkSomeBinaryWriter @BindingName (simpleBindingNameWriter name_w)
+ , mkSomeBinaryWriter @FastString fs_w
+ ]
- -- Make some initial state
- symtab_next <- newFastMutInt 0
- symtab_map <- newIORef emptyUFM :: IO (IORef (UniqFM Name (Int, HieName)))
- let hie_symtab = HieSymbolTable {
- hie_symtab_next = symtab_next,
- hie_symtab_map = symtab_map }
- dict_next_ref <- newFastMutInt 0
- dict_map_ref <- newIORef emptyUFM
- let hie_dict = HieDictionary {
- hie_dict_next = dict_next_ref,
- hie_dict_map = dict_map_ref }
-
- -- put the main thing
- let bh = setWriterUserData bh0
- $ newWriteState (putName hie_symtab)
- (putName hie_symtab)
- (putFastString hie_dict)
- put_ bh hiefile
-
- -- write the symtab pointer at the front of the file
- symtab_p <- tellBinWriter bh
- putAt bh symtab_p_p symtab_p
- seekBinWriter bh symtab_p
-
- -- write the symbol table itself
- symtab_next' <- readFastMutInt symtab_next
- symtab_map' <- readIORef symtab_map
- putSymbolTable bh symtab_next' symtab_map'
-
- -- write the dictionary pointer at the front of the file
- dict_p <- tellBinWriter bh
- putAt bh dict_p_p dict_p
- seekBinWriter bh dict_p
-
- -- write the dictionary itself
- dict_next <- readFastMutInt dict_next_ref
- dict_map <- readIORef dict_map_ref
- putDictionary bh dict_next dict_map
+ -- Discard number of written elements
+ -- Order matters! See Note [Order of deduplication tables during iface binary serialisation]
+ _ <- putAllTables bh [fs_tbl, name_tbl] $ do
+ put_ bh hiefile
-- and send the result to the file
createDirectoryIfMissing True (takeDirectory hie_file_path)
writeBinMem bh hie_file_path
return ()
+initWriteNameTable :: IO (WriterTable, BinaryWriter Name)
+initWriteNameTable = do
+ symtab_next <- newFastMutInt 0
+ symtab_map <- newIORef emptyUFM
+ let bin_symtab =
+ HieSymbolTable
+ { hie_symtab_next = symtab_next
+ , hie_symtab_map = symtab_map
+ }
+
+ let put_symtab bh = do
+ name_count <- readFastMutInt symtab_next
+ symtab_map <- readIORef symtab_map
+ putSymbolTable bh name_count symtab_map
+ pure name_count
+
+ return
+ ( WriterTable
+ { putTable = put_symtab
+ }
+ , mkWriter $ putName bin_symtab
+ )
+
+initReadNameTable :: NameCache -> IO (ReaderTable Name)
+initReadNameTable cache = do
+ return $
+ ReaderTable
+ { getTable = \bh -> getSymbolTable bh cache
+ , mkReaderFromTable = \tbl -> mkReader (getSymTabName tbl)
+ }
+
data HieFileResult
= HieFileResult
{ hie_file_result_version :: Integer
@@ -216,50 +211,29 @@ readHieFileHeader file bh0 = do
readHieFileContents :: ReadBinHandle -> NameCache -> IO HieFile
readHieFileContents bh0 name_cache = do
- dict <- get_dictionary bh0
+ fsReaderTable <- initFastStringReaderTable
+ nameReaderTable <- initReadNameTable name_cache
+
-- read the symbol table so we are capable of reading the actual data
- bh1 <- do
- let bh1 = setReaderUserData bh0
- $ newReadState (error "getSymtabName")
- (getDictFastString dict)
- symtab <- get_symbol_table bh1
- let bh1' = setReaderUserData bh1
- $ newReadState (getSymTabName symtab)
- (getDictFastString dict)
- return bh1'
+ bh1 <-
+ foldM (\bh tblReader -> tblReader bh) bh0
+ -- The order of these deserialisation matters!
+ --
+ -- See Note [Order of deduplication tables during iface binary serialisation] for details.
+ [ get_dictionary fsReaderTable
+ , get_dictionary nameReaderTable
+ ]
-- load the actual data
get bh1
where
- get_dictionary bin_handle = do
- dict_p <- get bin_handle
- data_p <- tellBinReader bin_handle
- seekBinReader bin_handle dict_p
- dict <- getDictionary bin_handle
- seekBinReader bin_handle data_p
- return dict
-
- get_symbol_table bh1 = do
- symtab_p <- get bh1
- data_p' <- tellBinReader bh1
- seekBinReader bh1 symtab_p
- symtab <- getSymbolTable bh1 name_cache
- seekBinReader bh1 data_p'
- return symtab
-
-putFastString :: HieDictionary -> WriteBinHandle -> FastString -> IO ()
-putFastString HieDictionary { hie_dict_next = j_r,
- hie_dict_map = out_r} bh f
- = do
- out <- readIORef out_r
- let !unique = getUnique f
- case lookupUFM_Directly out unique of
- Just (j, _) -> put_ bh (fromIntegral j :: Word32)
- Nothing -> do
- j <- readFastMutInt j_r
- put_ bh (fromIntegral j :: Word32)
- writeFastMutInt j_r (j + 1)
- writeIORef out_r $! addToUFM_Directly out unique (j, f)
+ get_dictionary tbl bin_handle = do
+ fsTable <- Binary.forwardGet bin_handle (getTable tbl bin_handle)
+ let
+ fsReader = mkReaderFromTable tbl fsTable
+ bhFs = addReaderToUserData fsReader bin_handle
+ pure bhFs
+
putSymbolTable :: WriteBinHandle -> Int -> UniqFM Name (Int,HieName) -> IO ()
putSymbolTable bh next_off symtab = do
=====================================
compiler/GHC/Iface/Load.hs
=====================================
@@ -26,6 +26,7 @@ module GHC.Iface.Load (
loadInterface,
loadSysInterface, loadUserInterface, loadPluginInterface,
findAndReadIface, readIface, writeIface,
+ flagsToIfCompression,
moduleFreeHolesPrecise,
needWiredInHomeIface, loadWiredInHomeIface,
@@ -965,11 +966,19 @@ read_file logger name_cache unit_state dflags wanted_mod file_path = do
-- | Write interface file
-writeIface :: Logger -> Profile -> FilePath -> ModIface -> IO ()
-writeIface logger profile hi_file_path new_iface
+writeIface :: Logger -> Profile -> CompressionIFace -> FilePath -> ModIface -> IO ()
+writeIface logger profile compression_level hi_file_path new_iface
= do createDirectoryIfMissing True (takeDirectory hi_file_path)
let printer = TraceBinIFace (debugTraceMsg logger 3)
- writeBinIface profile printer hi_file_path new_iface
+ writeBinIface profile printer compression_level hi_file_path new_iface
+
+flagsToIfCompression :: DynFlags -> CompressionIFace
+flagsToIfCompression dflags
+ | n <= 1 = NormalCompression
+ | n == 2 = SafeExtraCompression
+ -- n >= 3
+ | otherwise = MaximumCompression
+ where n = ifCompression dflags
-- | @readIface@ tries just the one file.
--
=====================================
compiler/GHC/Iface/Recomp/Binary.hs
=====================================
@@ -14,6 +14,7 @@ import GHC.Utils.Fingerprint
import GHC.Utils.Binary
import GHC.Types.Name
import GHC.Utils.Panic.Plain
+import GHC.Iface.Type (putIfaceType)
fingerprintBinMem :: WriteBinHandle -> IO Fingerprint
fingerprintBinMem bh = withBinBuffer bh f
@@ -34,8 +35,12 @@ computeFingerprint put_nonbinding_name a = do
put_ bh a
fingerprintBinMem bh
where
- set_user_data bh =
- setWriterUserData bh $ newWriteState put_nonbinding_name putNameLiterally putFS
+ set_user_data bh = setWriterUserData bh $ mkWriterUserData
+ [ mkSomeBinaryWriter $ mkWriter putIfaceType
+ , mkSomeBinaryWriter $ mkWriter put_nonbinding_name
+ , mkSomeBinaryWriter $ simpleBindingNameWriter $ mkWriter putNameLiterally
+ , mkSomeBinaryWriter $ mkWriter putFS
+ ]
-- | Used when we want to fingerprint a structure without depending on the
-- fingerprints of external Names that it refers to.
=====================================
compiler/GHC/Iface/Type.hs
=====================================
@@ -33,6 +33,8 @@ module GHC.Iface.Type (
ifForAllBndrVar, ifForAllBndrName, ifaceBndrName,
ifTyConBinderVar, ifTyConBinderName,
+ -- Binary utilities
+ putIfaceType, getIfaceType, ifaceTypeSharedByte,
-- Equality testing
isIfaceLiftedTypeKind,
@@ -90,11 +92,13 @@ import GHC.Utils.Misc
import GHC.Utils.Panic
import {-# SOURCE #-} GHC.Tc.Utils.TcType ( isMetaTyVar, isTyConableTyVar )
+import Data.Maybe (isJust)
+import Data.Proxy
+import qualified Data.Semigroup as Semi
+import Data.Word (Word8)
+import Control.Arrow (first)
import Control.DeepSeq
import Control.Monad ((<$!>))
-import Control.Arrow (first)
-import qualified Data.Semigroup as Semi
-import Data.Maybe( isJust )
{-
************************************************************************
@@ -192,6 +196,34 @@ data IfaceType
-- in interface file size (in GHC's boot libraries).
-- See !3987.
deriving (Eq, Ord)
+ -- See Note [Ord instance of IfaceType]
+
+{-
+Note [Ord instance of IfaceType]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We need an 'Ord' instance to have a 'Map' keyed by 'IfaceType'. This 'Map' is
+required for implementing the deduplication table during interface file
+serialisation.
+See Note [Deduplication during iface binary serialisation] for the implementation details.
+
+We experimented with a 'TrieMap' based implementation, but it seems to be
+slower than using a straight-forward 'Map IfaceType'.
+The experiments loaded the full agda library into a ghci session with the
+following scenarios:
+
+* normal: a plain ghci session.
+* cold: a ghci session that uses '-fwrite-if-simplified-core -fforce-recomp',
+ forcing a cold-cache.
+* warm: a subsequent ghci session that uses a warm cache for
+ '-fwrite-if-simplified-core', e.g. nothing needs to be recompiled.
+
+The implementation was up to 5% slower in some execution runs. However, on
+'lib:Cabal', the performance difference between 'Map IfaceType' and
+'TrieMap IfaceType' was negligible.
+
+We share our implementation of the 'TrieMap' in the ticket #24816, so that
+further performance analysis and improvements don't need to start from scratch.
+-}
type IfaceMult = IfaceType
@@ -2194,39 +2226,80 @@ ppr_parend_preds :: [IfacePredType] -> SDoc
ppr_parend_preds preds = parens (fsep (punctuate comma (map ppr preds)))
instance Binary IfaceType where
- put_ _ (IfaceFreeTyVar tv)
- = pprPanic "Can't serialise IfaceFreeTyVar" (ppr tv)
- -- See Note [Free TyVars and CoVars in IfaceType]
+ put_ bh ty =
+ case findUserDataWriter Proxy bh of
+ tbl -> putEntry tbl bh ty
- put_ bh (IfaceForAllTy aa ab) = do
- putByte bh 0
- put_ bh aa
- put_ bh ab
- put_ bh (IfaceTyVar ad) = do
- putByte bh 1
- put_ bh ad
- put_ bh (IfaceAppTy ae af) = do
- putByte bh 2
- put_ bh ae
- put_ bh af
- put_ bh (IfaceFunTy af aw ag ah) = do
- putByte bh 3
- put_ bh af
- put_ bh aw
- put_ bh ag
- put_ bh ah
- put_ bh (IfaceTyConApp tc tys)
- = do { putByte bh 5; put_ bh tc; put_ bh tys }
- put_ bh (IfaceCastTy a b)
- = do { putByte bh 6; put_ bh a; put_ bh b }
- put_ bh (IfaceCoercionTy a)
- = do { putByte bh 7; put_ bh a }
- put_ bh (IfaceTupleTy s i tys)
- = do { putByte bh 8; put_ bh s; put_ bh i; put_ bh tys }
- put_ bh (IfaceLitTy n)
- = do { putByte bh 9; put_ bh n }
+ get bh = getIfaceTypeShared bh
- get bh = do
+-- | This is the byte tag we expect to read when the next
+-- value is not an 'IfaceType' value, but an offset into a
+-- lookup table.
+-- See Note [Deduplication during iface binary serialisation].
+--
+-- Must not overlap with any byte tag in 'getIfaceType'.
+ifaceTypeSharedByte :: Word8
+ifaceTypeSharedByte = 99
+
+-- | Like 'getIfaceType' but checks for a specific byte tag
+-- that indicates that we won't be able to read a 'IfaceType' value
+-- but rather an offset into a lookup table. Consequentially,
+-- we look up the value for the 'IfaceType' in the look up table.
+--
+-- See Note [Deduplication during iface binary serialisation]
+-- for details.
+getIfaceTypeShared :: ReadBinHandle -> IO IfaceType
+getIfaceTypeShared bh = do
+ start <- tellBinReader bh
+ tag <- getByte bh
+ if ifaceTypeSharedByte == tag
+ then case findUserDataReader Proxy bh of
+ tbl -> getEntry tbl bh
+ else seekBinReader bh start >> getIfaceType bh
+
+-- | Serialises an 'IfaceType' to the given 'WriteBinHandle'.
+--
+-- Serialising inner 'IfaceType''s uses the 'Binary.put' of 'IfaceType' which may be using
+-- a deduplication table. See Note [Deduplication during iface binary serialisation].
+putIfaceType :: WriteBinHandle -> IfaceType -> IO ()
+putIfaceType _ (IfaceFreeTyVar tv)
+ = pprPanic "Can't serialise IfaceFreeTyVar" (ppr tv)
+ -- See Note [Free TyVars and CoVars in IfaceType]
+
+putIfaceType bh (IfaceForAllTy aa ab) = do
+ putByte bh 0
+ put_ bh aa
+ put_ bh ab
+putIfaceType bh (IfaceTyVar ad) = do
+ putByte bh 1
+ put_ bh ad
+putIfaceType bh (IfaceAppTy ae af) = do
+ putByte bh 2
+ put_ bh ae
+ put_ bh af
+putIfaceType bh (IfaceFunTy af aw ag ah) = do
+ putByte bh 3
+ put_ bh af
+ put_ bh aw
+ put_ bh ag
+ put_ bh ah
+putIfaceType bh (IfaceTyConApp tc tys)
+ = do { putByte bh 5; put_ bh tc; put_ bh tys }
+putIfaceType bh (IfaceCastTy a b)
+ = do { putByte bh 6; put_ bh a; put_ bh b }
+putIfaceType bh (IfaceCoercionTy a)
+ = do { putByte bh 7; put_ bh a }
+putIfaceType bh (IfaceTupleTy s i tys)
+ = do { putByte bh 8; put_ bh s; put_ bh i; put_ bh tys }
+putIfaceType bh (IfaceLitTy n)
+ = do { putByte bh 9; put_ bh n }
+
+-- | Deserialises an 'IfaceType' from the given 'ReadBinHandle'.
+--
+-- Reading inner 'IfaceType''s uses the 'Binary.get' of 'IfaceType' which may be using
+-- a deduplication table. See Note [Deduplication during iface binary serialisation].
+getIfaceType :: HasCallStack => ReadBinHandle -> IO IfaceType
+getIfaceType bh = do
h <- getByte bh
case h of
0 -> do aa <- get bh
=====================================
compiler/GHC/StgToJS/Object.hs
=====================================
@@ -314,7 +314,7 @@ putObject bh mod_name deps os = do
put_ bh (moduleNameString mod_name)
(fs_tbl, fs_writer) <- initFastStringWriterTable
- let bh_fs = addWriterToUserData (mkSomeBinaryWriter fs_writer) bh
+ let bh_fs = addWriterToUserData fs_writer bh
forwardPut_ bh (const (putTable fs_tbl bh_fs)) $ do
put_ bh_fs deps
=====================================
compiler/GHC/Utils/Binary.hs
=====================================
@@ -64,6 +64,8 @@ module GHC.Utils.Binary
-- * Lazy Binary I/O
lazyGet,
lazyPut,
+ lazyGet',
+ lazyPut',
lazyGetMaybe,
lazyPutMaybe,
@@ -86,10 +88,17 @@ module GHC.Utils.Binary
initFastStringReaderTable, initFastStringWriterTable,
putDictionary, getDictionary, putFS,
FSTable(..), getDictFastString, putDictFastString,
+ -- * Generic deduplication table
+ GenericSymbolTable(..),
+ initGenericSymbolTable,
+ getGenericSymtab, putGenericSymTab,
+ getGenericSymbolTable, putGenericSymbolTable,
-- * Newtype wrappers
BinSpan(..), BinSrcSpan(..), BinLocated(..),
-- * Newtypes for types that have canonically more than one valid encoding
BindingName(..),
+ simpleBindingNameWriter,
+ simpleBindingNameReader,
) where
import GHC.Prelude
@@ -102,11 +111,11 @@ import GHC.Utils.Panic.Plain
import GHC.Types.Unique.FM
import GHC.Data.FastMutInt
import GHC.Utils.Fingerprint
-import GHC.Utils.Misc (HasCallStack)
import GHC.Types.SrcLoc
import GHC.Types.Unique
import qualified GHC.Data.Strict as Strict
import GHC.Utils.Outputable( JoinPointHood(..) )
+import GHC.Utils.Misc ( HasCallStack, HasDebugCallStack )
import Control.DeepSeq
import Control.Monad ( when, (<$!>), unless, forM_, void )
@@ -132,6 +141,7 @@ import Data.List (unfoldr)
import System.IO as IO
import System.IO.Unsafe ( unsafeInterleaveIO )
import System.IO.Error ( mkIOError, eofErrorType )
+import Type.Reflection ( Typeable, SomeTypeRep(..) )
import qualified Type.Reflection as Refl
import GHC.Real ( Ratio(..) )
import Data.IntMap (IntMap)
@@ -142,6 +152,8 @@ import GHC.ForeignPtr ( unsafeWithForeignPtr )
import Unsafe.Coerce (unsafeCoerce)
+import GHC.Data.TrieMap
+
type BinArray = ForeignPtr Word8
#if !MIN_VERSION_base(4,15,0)
@@ -230,20 +242,28 @@ setReaderUserData bh us = bh { rbm_userData = us }
-- | Add 'SomeBinaryReader' as a known binary decoder.
-- If a 'BinaryReader' for the associated type already exists in 'ReaderUserData',
-- it is overwritten.
-addReaderToUserData :: SomeBinaryReader -> ReadBinHandle -> ReadBinHandle
-addReaderToUserData cache@(SomeBinaryReader typRep _) bh = bh
+addReaderToUserData :: forall a. Typeable a => BinaryReader a -> ReadBinHandle -> ReadBinHandle
+addReaderToUserData reader bh = bh
{ rbm_userData = (rbm_userData bh)
- { ud_reader_data = Map.insert (Refl.SomeTypeRep typRep) cache (ud_reader_data (rbm_userData bh))
+ { ud_reader_data =
+ let
+ typRep = Refl.typeRep @a
+ in
+ Map.insert (SomeTypeRep typRep) (SomeBinaryReader typRep reader) (ud_reader_data (rbm_userData bh))
}
}
-- | Add 'SomeBinaryWriter' as a known binary encoder.
-- If a 'BinaryWriter' for the associated type already exists in 'WriterUserData',
-- it is overwritten.
-addWriterToUserData :: SomeBinaryWriter -> WriteBinHandle -> WriteBinHandle
-addWriterToUserData cache@(SomeBinaryWriter typRep _) bh = bh
+addWriterToUserData :: forall a . Typeable a => BinaryWriter a -> WriteBinHandle -> WriteBinHandle
+addWriterToUserData writer bh = bh
{ wbm_userData = (wbm_userData bh)
- { ud_writer_data = Map.insert (Refl.SomeTypeRep typRep) cache (ud_writer_data (wbm_userData bh))
+ { ud_writer_data =
+ let
+ typRep = Refl.typeRep @a
+ in
+ Map.insert (SomeTypeRep typRep) (SomeBinaryWriter typRep writer) (ud_writer_data (wbm_userData bh))
}
}
@@ -1102,24 +1122,32 @@ forwardGet bh get_A = do
-- Lazy reading/writing
lazyPut :: Binary a => WriteBinHandle -> a -> IO ()
-lazyPut bh a = do
+lazyPut = lazyPut' put_
+
+lazyGet :: Binary a => ReadBinHandle -> IO a
+lazyGet = lazyGet' get
+
+lazyPut' :: HasDebugCallStack => (WriteBinHandle -> a -> IO ()) -> WriteBinHandle -> a -> IO ()
+lazyPut' f bh a = do
-- output the obj with a ptr to skip over it:
pre_a <- tellBinWriter bh
put_ bh pre_a -- save a slot for the ptr
- put_ bh a -- dump the object
+ f bh a -- dump the object
q <- tellBinWriter bh -- q = ptr to after object
putAt bh pre_a q -- fill in slot before a with ptr to q
seekBinWriter bh q -- finally carry on writing at q
-lazyGet :: Binary a => ReadBinHandle -> IO a
-lazyGet bh = do
+lazyGet' :: HasDebugCallStack => (ReadBinHandle -> IO a) -> ReadBinHandle -> IO a
+lazyGet' f bh = do
p <- get bh -- a BinPtr
p_a <- tellBinReader bh
a <- unsafeInterleaveIO $ do
- -- NB: Use a fresh off_r variable in the child thread, for thread
+ -- NB: Use a fresh rbm_off_r variable in the child thread, for thread
-- safety.
off_r <- newFastMutInt 0
- getAt bh { rbm_off_r = off_r } p_a
+ let bh' = bh { rbm_off_r = off_r }
+ seekBinReader bh' p_a
+ f bh'
seekBinReader bh p -- skip over the object for now
return a
@@ -1173,6 +1201,12 @@ lazyGetMaybe bh = do
newtype BindingName = BindingName { getBindingName :: Name }
deriving ( Eq )
+simpleBindingNameWriter :: BinaryWriter Name -> BinaryWriter BindingName
+simpleBindingNameWriter = coerce
+
+simpleBindingNameReader :: BinaryReader Name -> BinaryReader BindingName
+simpleBindingNameReader = coerce
+
-- | Existential for 'BinaryWriter' with a type witness.
data SomeBinaryWriter = forall a . SomeBinaryWriter (Refl.TypeRep a) (BinaryWriter a)
@@ -1184,7 +1218,7 @@ data SomeBinaryReader = forall a . SomeBinaryReader (Refl.TypeRep a) (BinaryRead
-- See Note [Binary UserData]
data WriterUserData =
WriterUserData {
- ud_writer_data :: Map Refl.SomeTypeRep SomeBinaryWriter
+ ud_writer_data :: Map SomeTypeRep SomeBinaryWriter
-- ^ A mapping from a type witness to the 'Writer' for the associated type.
-- This is a 'Map' because microbenchmarks indicated this is more efficient
-- than other representations for less than ten elements.
@@ -1201,7 +1235,7 @@ data WriterUserData =
-- See Note [Binary UserData]
data ReaderUserData =
ReaderUserData {
- ud_reader_data :: Map Refl.SomeTypeRep SomeBinaryReader
+ ud_reader_data :: Map SomeTypeRep SomeBinaryReader
-- ^ A mapping from a type witness to the 'Reader' for the associated type.
-- This is a 'Map' because microbenchmarks indicated this is more efficient
-- than other representations for less than ten elements.
@@ -1215,12 +1249,12 @@ data ReaderUserData =
mkWriterUserData :: [SomeBinaryWriter] -> WriterUserData
mkWriterUserData caches = noWriterUserData
- { ud_writer_data = Map.fromList $ map (\cache@(SomeBinaryWriter typRep _) -> (Refl.SomeTypeRep typRep, cache)) caches
+ { ud_writer_data = Map.fromList $ map (\cache@(SomeBinaryWriter typRep _) -> (SomeTypeRep typRep, cache)) caches
}
mkReaderUserData :: [SomeBinaryReader] -> ReaderUserData
mkReaderUserData caches = noReaderUserData
- { ud_reader_data = Map.fromList $ map (\cache@(SomeBinaryReader typRep _) -> (Refl.SomeTypeRep typRep, cache)) caches
+ { ud_reader_data = Map.fromList $ map (\cache@(SomeBinaryReader typRep _) -> (SomeTypeRep typRep, cache)) caches
}
mkSomeBinaryWriter :: forall a . Refl.Typeable a => BinaryWriter a -> SomeBinaryWriter
@@ -1346,6 +1380,110 @@ newtype WriterTable = WriterTable
-- ^ Serialise a table to disk. Returns the number of written elements.
}
+-- ----------------------------------------------------------------------------
+-- Common data structures for constructing and maintaining lookup tables for
+-- binary serialisation and deserialisation.
+-- ----------------------------------------------------------------------------
+
+-- | The 'GenericSymbolTable' stores a mapping from already seen elements to an index.
+-- If an element wasn't seen before, it is added to the mapping together with a fresh
+-- index.
+--
+-- 'GenericSymbolTable' is a variant of a 'BinSymbolTable' that is polymorphic in the table implementation.
+-- As such it can be used with any container that implements the 'TrieMap' type class.
+--
+-- While 'GenericSymbolTable' is similar to the 'BinSymbolTable', it supports storing tree-like
+-- structures such as 'Type' and 'IfaceType' more efficiently.
+--
+data GenericSymbolTable m = GenericSymbolTable
+ { gen_symtab_next :: !FastMutInt
+ -- ^ The next index to use.
+ , gen_symtab_map :: !(IORef (m Int))
+ -- ^ Given a symbol, find the symbol and return its index.
+ , gen_symtab_to_write :: !(IORef [Key m])
+ -- ^ Reversed list of values to write into the buffer.
+ -- This is an optimisation, as it allows us to write out quickly all
+ -- newly discovered values that are discovered when serialising 'Key m'
+ -- to disk.
+ }
+
+-- | Initialise a 'GenericSymbolTable', initialising the index to '0'.
+initGenericSymbolTable :: TrieMap m => IO (GenericSymbolTable m)
+initGenericSymbolTable = do
+ symtab_next <- newFastMutInt 0
+ symtab_map <- newIORef emptyTM
+ symtab_todo <- newIORef []
+ pure $ GenericSymbolTable
+ { gen_symtab_next = symtab_next
+ , gen_symtab_map = symtab_map
+ , gen_symtab_to_write = symtab_todo
+ }
+
+-- | Serialise the 'GenericSymbolTable' to disk.
+--
+-- Since 'GenericSymbolTable' stores tree-like structures, such as 'IfaceType',
+-- serialising an element can add new elements to the mapping.
+-- Thus, 'putGenericSymbolTable' first serialises all values, and then checks whether any
+-- new elements have been discovered. If so, repeat the loop.
+putGenericSymbolTable :: forall m. (TrieMap m) => GenericSymbolTable m -> (WriteBinHandle -> Key m -> IO ()) -> WriteBinHandle -> IO Int
+{-# INLINE putGenericSymbolTable #-}
+putGenericSymbolTable gen_sym_tab serialiser bh = do
+ putGenericSymbolTable bh
+ where
+ symtab_next = gen_symtab_next gen_sym_tab
+ symtab_to_write = gen_symtab_to_write gen_sym_tab
+ putGenericSymbolTable :: WriteBinHandle -> IO Int
+ putGenericSymbolTable bh = do
+ let loop = do
+ vs <- atomicModifyIORef' symtab_to_write (\a -> ([], a))
+ case vs of
+ [] -> readFastMutInt symtab_next
+ todo -> do
+ mapM_ (\n -> serialiser bh n) (reverse todo)
+ loop
+ snd <$>
+ (forwardPut bh (const $ readFastMutInt symtab_next >>= put_ bh) $
+ loop)
+
+-- | Read the elements of a 'GenericSymbolTable' from disk into a 'SymbolTable'.
+getGenericSymbolTable :: forall a . (ReadBinHandle -> IO a) -> ReadBinHandle -> IO (SymbolTable a)
+getGenericSymbolTable deserialiser bh = do
+ sz <- forwardGet bh (get bh) :: IO Int
+ mut_arr <- newArray_ (0, sz-1) :: IO (IOArray Int a)
+ forM_ [0..(sz-1)] $ \i -> do
+ f <- deserialiser bh
+ writeArray mut_arr i f
+ unsafeFreeze mut_arr
+
+-- | Write an element 'Key m' to the given 'WriteBinHandle'.
+--
+-- If the element was seen before, we simply write the index of that element to the
+-- 'WriteBinHandle'. If we haven't seen it before, we add the element to
+-- the 'GenericSymbolTable', increment the index, and return this new index.
+putGenericSymTab :: (TrieMap m) => GenericSymbolTable m -> WriteBinHandle -> Key m -> IO ()
+{-# INLINE putGenericSymTab #-}
+putGenericSymTab GenericSymbolTable{
+ gen_symtab_map = symtab_map_ref,
+ gen_symtab_next = symtab_next,
+ gen_symtab_to_write = symtab_todo }
+ bh val = do
+ symtab_map <- readIORef symtab_map_ref
+ case lookupTM val symtab_map of
+ Just off -> put_ bh (fromIntegral off :: Word32)
+ Nothing -> do
+ off <- readFastMutInt symtab_next
+ writeFastMutInt symtab_next (off+1)
+ writeIORef symtab_map_ref
+ $! insertTM val off symtab_map
+ atomicModifyIORef symtab_todo (\todo -> (val : todo, ()))
+ put_ bh (fromIntegral off :: Word32)
+
+-- | Read a value from a 'SymbolTable'.
+getGenericSymtab :: Binary a => SymbolTable a -> ReadBinHandle -> IO a
+getGenericSymtab symtab bh = do
+ i :: Word32 <- get bh
+ return $! symtab ! fromIntegral i
+
---------------------------------------------------------
-- The Dictionary
---------------------------------------------------------
=====================================
docs/users_guide/using-optimisation.rst
=====================================
@@ -1814,3 +1814,23 @@ as such you shouldn't need to set any of them explicitly. A flag
This flag sets the size (in bytes) threshold above which the second approach
is used. You can disable the second approach entirely by setting the
threshold to 0.
+
+.. ghc-flag:: -fwrite-if-compression=⟨n⟩
+ :shortdesc: *default: 2.* Tweak the level of interface file compression.
+ :type: dynamic
+ :category: optimization
+
+ :default: 2
+
+ This flag defines the level of compression of interface files when writing to disk.
+ The higher the flag, the more we deduplicate the interface file, at the cost of a higher compilation time.
+ Deduplication (when applied to :ghc-flag:`--make` mode and :ghc-flag:`--interactive` mode) decreases the size of interface files as well as reducing
+ the overall memory usage of GHC.
+
+ Compression cannot be fully turned off, GHC always compresses interface files to a certain degree.
+ Currently, we support values of ``1``, ``2`` and ``3``.
+ Lower or higher values are clamped to ``1`` and ``3`` respectively.
+
+ * ``1``: Compress as little as possible. No run-time impact, at the cost of interface file size and memory usage.
+ * ``2``: Apply compression with minimal run-time overhead, reducing the interface file size and memory usage.
+ * ``3``: Apply all possible compressions, minimal interface file sizes and memory usage, at the cost of run-time overhead.
=====================================
testsuite/tests/iface/IfaceSharingIfaceType.hs
=====================================
@@ -0,0 +1,44 @@
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module IfaceSharingIfaceType (types) where
+
+import GHC.Data.FastString
+import GHC.Builtin.Uniques
+import GHC.Builtin.Names
+import GHC.Builtin.Types
+import GHC.Types.Name
+import GHC.Types.SrcLoc
+import GHC.Iface.Type
+import GHC.CoreToIface
+import GHC.Core.TyCo.Rep
+import GHC
+
+[f1,f2,f3,f4,f5] = map mkVarOcc ["a", "b","c","d","e"]
+
+[u1,u2,u3,u4,u5] = map mkPreludeMiscIdUnique [10000..10004]
+
+names = [ mkExternalName u1 pRELUDE f1 noSrcSpan
+ , mkExternalName u2 pRELUDE f2 noSrcSpan
+ , mkExternalName u3 pRELUDE f3 noSrcSpan
+ , mkExternalName u4 pRELUDE f4 noSrcSpan
+ , mkExternalName u5 pRELUDE f5 noSrcSpan ]
+
+-- Int
+intIfaceTy = toIfaceType intTy
+
+wordIfaceTy = toIfaceType wordTy
+
+listIntTy = toIfaceType (mkListTy intTy)
+
+funTy = (intTy `mkVisFunTyMany` wordTy `mkVisFunTyMany` mkListTy intTy)
+
+funIfaceTy = toIfaceType funTy
+
+reallyBigFunTy = toIfaceType (funTy `mkVisFunTyMany` funTy `mkVisFunTyMany` funTy `mkVisFunTyMany` funTy)
+
+forallIfaceTy = toIfaceType (dataConType justDataCon)
+
+
+types = [intIfaceTy, wordIfaceTy, listIntTy, funIfaceTy, reallyBigFunTy, forallIfaceTy]
+
=====================================
testsuite/tests/iface/IfaceSharingName.hs
=====================================
@@ -0,0 +1,21 @@
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module IfaceSharingName where
+
+import Lib
+import GHC.Data.FastString
+import GHC.Builtin.Uniques
+import GHC.Builtin.Names
+import GHC.Types.Name
+import GHC.Types.SrcLoc
+
+[f1,f2,f3,f4,f5] = map mkVarOcc ["a", "b","c","d","e"]
+
+[u1,u2,u3,u4,u5] = map mkPreludeMiscIdUnique [10000..10004]
+
+names = [ mkExternalName u1 pRELUDE f1 noSrcSpan
+ , mkExternalName u2 pRELUDE f2 noSrcSpan
+ , mkExternalName u3 pRELUDE f3 noSrcSpan
+ , mkExternalName u4 pRELUDE f4 noSrcSpan
+ , mkExternalName u5 pRELUDE f5 noSrcSpan ]
=====================================
testsuite/tests/iface/Lib.hs
=====================================
@@ -0,0 +1,15 @@
+module Lib where
+
+import GHC.Utils.Binary
+import GHC.Iface.Binary
+import qualified Data.ByteString as B
+import System.Environment
+import Data.Maybe
+
+testSize :: Binary a => CompressionIFace -> a -> IO Int
+testSize compLvl payload = do
+ args <- getArgs
+ bh <- openBinMem 1024
+ putWithUserData QuietBinIFace compLvl bh payload
+ withBinBuffer bh (\b -> return (B.length b))
+
=====================================
testsuite/tests/iface/Makefile
=====================================
@@ -0,0 +1,4 @@
+TOP=../..
+include $(TOP)/mk/boilerplate.mk
+include $(TOP)/mk/test.mk
+
=====================================
testsuite/tests/iface/all.T
=====================================
@@ -0,0 +1,24 @@
+test( 'if_faststring'
+ , [ stat_from_file('if_compression(1)', 5, 'NORMALSIZE')
+ , stat_from_file('if_compression(2)', 5, 'MEDIUMSIZE')
+ , stat_from_file('if_compression(3)', 5, 'FULLSIZE')
+ , extra_files(["Lib.hs"])]
+ , compile_and_run
+ , ['-package ghc'])
+
+test( 'if_name'
+ , [ stat_from_file('if_compression(1)', 5, 'NORMALSIZE')
+ , stat_from_file('if_compression(2)', 5, 'MEDIUMSIZE')
+ , stat_from_file('if_compression(3)', 5, 'FULLSIZE')
+ , extra_files(["Lib.hs", "IfaceSharingName.hs"])]
+ , compile_and_run
+ , ['-package ghc'])
+
+test( 'if_ifacetype'
+ , [ stat_from_file('if_compression(1)', 5, 'NORMALSIZE')
+ , stat_from_file('if_compression(2)', 5, 'MEDIUMSIZE')
+ , stat_from_file('if_compression(3)', 5, 'FULLSIZE')
+ , extra_files(["Lib.hs", "IfaceSharingIfaceType.hs"])]
+ , compile_and_run
+ , ['-package ghc'])
+
=====================================
testsuite/tests/iface/if_faststring.hs
=====================================
@@ -0,0 +1,15 @@
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+import Lib
+import GHC.Data.FastString
+import GHC.Iface.Binary
+
+main :: IO ()
+main = do
+ sz <- testSize MaximumCompression (concat (replicate 1000 ["abc", "cde", "efg" :: FastString]))
+ writeFile "FULLSIZE" (show sz)
+ sz <- testSize SafeExtraCompression (concat (replicate 1000 ["abc", "cde", "efg" :: FastString]))
+ writeFile "MEDIUMSIZE" (show sz)
+ sz <- testSize NormalCompression (concat (replicate 1000 ["abc", "cde", "efg" :: FastString]))
+ writeFile "NORMALSIZE" (show sz)
=====================================
testsuite/tests/iface/if_ifacetype.hs
=====================================
@@ -0,0 +1,13 @@
+import Lib
+import IfaceSharingIfaceType
+import GHC.Iface.Binary
+
+main :: IO ()
+main = do
+ sz <- testSize MaximumCompression (concat (replicate 500 types))
+ writeFile "FULLSIZE" (show sz)
+ sz <- testSize SafeExtraCompression (concat (replicate 500 types))
+ writeFile "MEDIUMSIZE" (show sz)
+ sz <- testSize NormalCompression (concat (replicate 500 types))
+ writeFile "NORMALSIZE" (show sz)
+
=====================================
testsuite/tests/iface/if_name.hs
=====================================
@@ -0,0 +1,12 @@
+import Lib
+import IfaceSharingName
+import GHC.Iface.Binary
+
+main :: IO ()
+main = do
+ sz <- testSize MaximumCompression (concat (replicate 1000 names))
+ writeFile "FULLSIZE" (show sz)
+ sz <- testSize SafeExtraCompression (concat (replicate 1000 names))
+ writeFile "MEDIUMSIZE" (show sz)
+ sz <- testSize NormalCompression (concat (replicate 1000 names))
+ writeFile "NORMALSIZE" (show sz)
=====================================
utils/haddock
=====================================
@@ -1 +1 @@
-Subproject commit a711607e29b925f3d69e27c5fde4ba655c711ff1
+Subproject commit c9bc29c6a708483d2abc3d8ec9262510ce87ca61
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/0c246d82ed9eb74d109c05cddb93d9dd40c23896...63c71dc4a0d7bb35eb5152d404861186a838038c
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/0c246d82ed9eb74d109c05cddb93d9dd40c23896...63c71dc4a0d7bb35eb5152d404861186a838038c
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