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The function typePrimRepArgs is just a thin wrapper around typePrimRep, adding a VoidRep if the list is empty. However, in StgToByteCode, we were discarding that VoidRep anyway, so there's no point in calling it.
The function typePrimRepArgs is just a thin wrapper around typePrimRep, adding a VoidRep if the list is empty. However, in StgToByteCode, we were discarding that VoidRep anyway, so there's no point in calling it.
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StgToByteCode.hs 88.50 KiB
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE FlexibleContexts #-}
{-# OPTIONS_GHC -fprof-auto-top #-}
--
-- (c) The University of Glasgow 2002-2006
--
-- | GHC.StgToByteCode: Generate bytecode from STG
module GHC.StgToByteCode ( UnlinkedBCO, byteCodeGen) where
import GHC.Prelude
import GHC.Driver.DynFlags
import GHC.Driver.Env
import GHC.ByteCode.Instr
import GHC.ByteCode.Asm
import GHC.ByteCode.Types
import GHC.Cmm.CallConv
import GHC.Cmm.Expr
import GHC.Cmm.Node
import GHC.Cmm.Utils
import GHC.Platform
import GHC.Platform.Profile
import GHC.Runtime.Interpreter
import GHCi.FFI
import GHCi.RemoteTypes
import GHC.Types.Basic
import GHC.Utils.Outputable
import GHC.Types.Name
import GHC.Types.Id
import GHC.Types.ForeignCall
import GHC.Core
import GHC.Types.Literal
import GHC.Builtin.PrimOps
import GHC.Builtin.PrimOps.Ids (primOpId)
import GHC.Core.Type
import GHC.Core.TyCo.Compare (eqType)
import GHC.Types.RepType
import GHC.Core.DataCon
import GHC.Core.TyCon
import GHC.Utils.Misc
import GHC.Utils.Logger
import GHC.Types.Var.Set
import GHC.Builtin.Types.Prim
import GHC.Core.TyCo.Ppr ( pprType )
import GHC.Utils.Error
import GHC.Builtin.Uniques
import GHC.Data.FastString
import GHC.Utils.Panic
import GHC.Utils.Exception (evaluate)
import GHC.StgToCmm.Closure ( NonVoid(..), fromNonVoid, nonVoidIds )
import GHC.StgToCmm.Layout
import GHC.Runtime.Heap.Layout hiding (WordOff, ByteOff, wordsToBytes)
import GHC.Data.Bitmap
import GHC.Data.OrdList
import GHC.Data.Maybe
import GHC.Types.Name.Env (mkNameEnv)
import GHC.Types.Tickish
import Data.List ( genericReplicate, genericLength, intersperse
, partition, scanl', sortBy, zip4, zip6 )import Foreign hiding (shiftL, shiftR)
import Control.Monad
import Data.Char
import GHC.Unit.Module
import GHC.Unit.Home.ModInfo (lookupHpt)
import Data.Array
import Data.Coerce (coerce)
import Data.ByteString (ByteString)
import Data.Map (Map)
import Data.IntMap (IntMap)
import Data.List.NonEmpty (NonEmpty(..))
import qualified Data.Map as Map
import qualified Data.IntMap as IntMap
import qualified GHC.Data.FiniteMap as Map
import Data.Ord
import GHC.Stack.CCS
import Data.Either ( partitionEithers )
import GHC.Stg.Syntax
import qualified Data.IntSet as IntSet
import GHC.CoreToIface
-- -----------------------------------------------------------------------------
-- Generating byte code for a complete module
byteCodeGen :: HscEnv
-> Module
-> [CgStgTopBinding]
-> [TyCon]
-> Maybe ModBreaks
-> IO CompiledByteCode
byteCodeGen hsc_env this_mod binds tycs mb_modBreaks
= withTiming logger
(text "GHC.StgToByteCode"<+>brackets (ppr this_mod))
(const ()) $ do
-- Split top-level binds into strings and others.
-- See Note [Generating code for top-level string literal bindings].
let (strings, lifted_binds) = partitionEithers $ do -- list monad
bnd <- binds
case bnd of
StgTopLifted bnd -> [Right bnd]
StgTopStringLit b str -> [Left (b, str)]
flattenBind (StgNonRec b e) = [(b,e)]
flattenBind (StgRec bs) = bs
stringPtrs <- allocateTopStrings interp strings
(BcM_State{..}, proto_bcos) <-
runBc hsc_env this_mod mb_modBreaks $ do
let flattened_binds = concatMap flattenBind (reverse lifted_binds)
mapM schemeTopBind flattened_binds
when (notNull ffis)
(panic "GHC.StgToByteCode.byteCodeGen: missing final emitBc?")
putDumpFileMaybe logger Opt_D_dump_BCOs
"Proto-BCOs" FormatByteCode
(vcat (intersperse (char ' ') (map ppr proto_bcos)))
cbc <- assembleBCOs interp profile proto_bcos tycs stringPtrs
(case modBreaks of
Nothing -> Nothing
Just mb -> Just mb{ modBreaks_breakInfo = breakInfo })
-- Squash space leaks in the CompiledByteCode. This is really
-- important, because when loading a set of modules into GHCi
-- we don't touch the CompiledByteCode until the end when we
-- do linking. Forcing out the thunks here reduces space
-- usage by more than 50% when loading a large number of -- modules.
evaluate (seqCompiledByteCode cbc)
return cbc
where dflags = hsc_dflags hsc_env
logger = hsc_logger hsc_env
interp = hscInterp hsc_env
profile = targetProfile dflags
-- | see Note [Generating code for top-level string literal bindings]
allocateTopStrings
:: Interp
-> [(Id, ByteString)]
-> IO AddrEnv
allocateTopStrings interp topStrings = do
let !(bndrs, strings) = unzip topStrings
ptrs <- interpCmd interp $ MallocStrings strings
return $ mkNameEnv (zipWith mk_entry bndrs ptrs)
where
mk_entry bndr ptr = let nm = getName bndr
in (nm, (nm, AddrPtr ptr))
{- Note [Generating code for top-level string literal bindings]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
As described in Note [Compilation plan for top-level string literals]
in GHC.Core, the core-to-core optimizer can introduce top-level Addr#
bindings to represent string literals. The creates two challenges for
the bytecode compiler: (1) compiling the bindings themselves, and
(2) compiling references to such bindings. Here is a summary on how
we deal with them:
1. Top-level string literal bindings are separated from the rest of
the module. Memory for them is allocated immediately, via
interpCmd, in allocateTopStrings, and the resulting AddrEnv is
recorded in the bc_strs field of the CompiledByteCode result.
2. When we encounter a reference to a top-level string literal, we
generate a PUSH_ADDR pseudo-instruction, which is assembled to
a PUSH_UBX instruction with a BCONPtrAddr argument.
3. The loader accumulates string literal bindings from loaded
bytecode in the addr_env field of the LinkerEnv.
4. The BCO linker resolves BCONPtrAddr references by searching both
the addr_env (to find literals defined in bytecode) and the native
symbol table (to find literals defined in native code).
This strategy works alright, but it does have one significant problem:
we never free the memory that we allocate for the top-level strings.
In theory, we could explicitly free it when BCOs are unloaded, but
this comes with its own complications; see #22400 for why. For now,
we just accept the leak, but it would nice to find something better. -}
-- -----------------------------------------------------------------------------
-- Compilation schema for the bytecode generator
type BCInstrList = OrdList BCInstr
wordsToBytes :: Platform -> WordOff -> ByteOff
wordsToBytes platform = fromIntegral . (* platformWordSizeInBytes platform) . fromIntegral
-- Used when we know we have a whole number of words
bytesToWords :: Platform -> ByteOff -> WordOff
bytesToWords platform (ByteOff bytes) =
let (q, r) = bytes `quotRem` (platformWordSizeInBytes platform)
in if r == 0
then fromIntegral q
else pprPanic "GHC.StgToByteCode.bytesToWords"
(text "bytes=" <> ppr bytes)
wordSize :: Platform -> ByteOff
wordSize platform = ByteOff (platformWordSizeInBytes platform)
type Sequel = ByteOff -- back off to this depth before ENTER
type StackDepth = ByteOff
-- | Maps Ids to their stack depth. This allows us to avoid having to mess with
-- it after each push/pop.
type BCEnv = Map Id StackDepth -- To find vars on the stack
{-
ppBCEnv :: BCEnv -> SDoc
ppBCEnv p
= text "begin-env"
$$ nest 4 (vcat (map pp_one (sortBy cmp_snd (Map.toList p))))
$$ text "end-env"
where
pp_one (var, ByteOff offset) = int offset <> colon <+> ppr var <+> ppr (bcIdArgReps var)
cmp_snd x y = compare (snd x) (snd y)
-}
-- Create a BCO and do a spot of peephole optimisation on the insns
-- at the same time.
mkProtoBCO
:: Platform
-> name
-> BCInstrList
-> Either [CgStgAlt] (CgStgRhs)
-- ^ original expression; for debugging only
-> Int -- ^ arity
-> WordOff -- ^ bitmap size
-> [StgWord] -- ^ bitmap
-> Bool -- ^ True <=> is a return point, rather than a function
-> [FFIInfo]
-> ProtoBCO name
mkProtoBCO platform nm instrs_ordlist origin arity bitmap_size bitmap is_ret ffis
= ProtoBCO {
protoBCOName = nm,
protoBCOInstrs = maybe_with_stack_check,
protoBCOBitmap = bitmap,
protoBCOBitmapSize = fromIntegral bitmap_size,
protoBCOArity = arity,
protoBCOExpr = origin,
protoBCOFFIs = ffis
}
where
-- Overestimate the stack usage (in words) of this BCO,
-- and if >= iNTERP_STACK_CHECK_THRESH, add an explicit
-- stack check. (The interpreter always does a stack check
-- for iNTERP_STACK_CHECK_THRESH words at the start of each
-- BCO anyway, so we only need to add an explicit one in the
-- (hopefully rare) cases when the (overestimated) stack use
-- exceeds iNTERP_STACK_CHECK_THRESH.
maybe_with_stack_check
| is_ret && stack_usage < fromIntegral (pc_AP_STACK_SPLIM (platformConstants platform)) = peep_d
-- don't do stack checks at return points,
-- everything is aggregated up to the top BCO
-- (which must be a function).
-- That is, unless the stack usage is >= AP_STACK_SPLIM,
-- see bug #1466.
| stack_usage >= fromIntegral iNTERP_STACK_CHECK_THRESH
= STKCHECK stack_usage : peep_d
| otherwise
= peep_d -- the supposedly common case
-- We assume that this sum doesn't wrap
stack_usage = sum (map bciStackUse peep_d)
-- Merge local pushes
peep_d = peep (fromOL instrs_ordlist)
peep (PUSH_L off1 : PUSH_L off2 : PUSH_L off3 : rest)
= PUSH_LLL off1 (off2-1) (off3-2) : peep rest
peep (PUSH_L off1 : PUSH_L off2 : rest)
= PUSH_LL off1 (off2-1) : peep rest
peep (i:rest)
= i : peep rest
peep []
= []
argBits :: Platform -> [ArgRep] -> [Bool]
argBits _ [] = []
argBits platform (rep : args)
| isFollowableArg rep = False : argBits platform args
| otherwise = replicate (argRepSizeW platform rep) True ++ argBits platform args
-- -----------------------------------------------------------------------------
-- schemeTopBind
-- Compile code for the right-hand side of a top-level binding
schemeTopBind :: (Id, CgStgRhs) -> BcM (ProtoBCO Name)
schemeTopBind (id, rhs)
| Just data_con <- isDataConWorkId_maybe id,
isNullaryRepDataCon data_con = do
platform <- profilePlatform <$> getProfile
-- Special case for the worker of a nullary data con.
-- It'll look like this: Nil = /\a -> Nil a
-- If we feed it into schemeR, we'll get
-- Nil = Nil
-- because mkConAppCode treats nullary constructor applications
-- by just re-using the single top-level definition. So
-- for the worker itself, we must allocate it directly.
-- ioToBc (putStrLn $ "top level BCO")
emitBc (mkProtoBCO platform (getName id) (toOL [PACK data_con 0, RETURN P])
(Right rhs) 0 0 [{-no bitmap-}] False{-not alts-})
| otherwise
= schemeR [{- No free variables -}] (getName id, rhs)
-- -----------------------------------------------------------------------------
-- schemeR
-- Compile code for a right-hand side, to give a BCO that,
-- when executed with the free variables and arguments on top of the stack,
-- will return with a pointer to the result on top of the stack, after
-- removing the free variables and arguments.
--
-- Park the resulting BCO in the monad. Also requires the
-- name of the variable to which this value was bound,
-- so as to give the resulting BCO a name.
schemeR :: [Id] -- Free vars of the RHS, ordered as they
-- will appear in the thunk. Empty for
-- top-level things, which have no free vars.
-> (Name, CgStgRhs)
-> BcM (ProtoBCO Name)
schemeR fvs (nm, rhs)
= schemeR_wrk fvs nm rhs (collect rhs)
-- If an expression is a lambda, return the
-- list of arguments to the lambda (in R-to-L order) and the
-- underlying expression
collect :: CgStgRhs -> ([Var], CgStgExpr)
collect (StgRhsClosure _ _ _ args body _) = (args, body)
collect (StgRhsCon _cc dc cnum _ticks args _typ) = ([], StgConApp dc cnum args [])
schemeR_wrk
:: [Id]
-> Name
-> CgStgRhs -- expression e, for debugging only
-> ([Var], CgStgExpr) -- result of collect on e
-> BcM (ProtoBCO Name)
schemeR_wrk fvs nm original_body (args, body)
= do
profile <- getProfile
let
platform = profilePlatform profile
all_args = reverse args ++ fvs
arity = length all_args
-- all_args are the args in reverse order. We're compiling a function
-- \fv1..fvn x1..xn -> e
-- i.e. the fvs come first
-- Stack arguments always take a whole number of words, we never pack
-- them unlike constructor fields.
szsb_args = map (wordsToBytes platform . idSizeW platform) all_args
sum_szsb_args = sum szsb_args
p_init = Map.fromList (zip all_args (mkStackOffsets 0 szsb_args))
-- make the arg bitmap
bits = argBits platform (reverse (map (bcIdArgRep platform) all_args))
bitmap_size = genericLength bits
bitmap = mkBitmap platform bits
body_code <- schemeER_wrk sum_szsb_args p_init body
emitBc (mkProtoBCO platform nm body_code (Right original_body)
arity bitmap_size bitmap False{-not alts-})
-- | Introduce break instructions for ticked expressions.
-- If no breakpoint information is available, the instruction is omitted.
schemeER_wrk :: StackDepth -> BCEnv -> CgStgExpr -> BcM BCInstrList
schemeER_wrk d p (StgTick (Breakpoint tick_ty tick_no fvs mod) rhs) = do
code <- schemeE d 0 p rhs
hsc_env <- getHscEnv
current_mod <- getCurrentModule
current_mod_breaks <- getCurrentModBreaks
case break_info hsc_env mod current_mod current_mod_breaks of
Nothing -> pure code
Just ModBreaks {modBreaks_flags = breaks, modBreaks_module = mod_ptr} -> do
cc_arr <- getCCArray
platform <- profilePlatform <$> getProfile
let idOffSets = getVarOffSets platform d p fvs
ty_vars = tyCoVarsOfTypesWellScoped (tick_ty:map idType fvs)
toWord :: Maybe (Id, WordOff) -> Maybe (Id, Word)
toWord = fmap (\(i, wo) -> (i, fromIntegral wo))
breakInfo = dehydrateCgBreakInfo ty_vars (map toWord idOffSets) tick_ty
newBreakInfo tick_no breakInfo
let cc | Just interp <- hsc_interp hsc_env
, interpreterProfiled interp
= cc_arr ! tick_no
| otherwise = toRemotePtr nullPtr
breakInstr = BRK_FUN breaks (fromIntegral tick_no) mod_ptr cc
return $ breakInstr `consOL` code
schemeER_wrk d p rhs = schemeE d 0 p rhs
-- | Determine the GHCi-allocated 'BreakArray' and module pointer for the module
-- from which the breakpoint originates.
-- These are stored in 'ModBreaks' as remote pointers in order to allow the BCOs
-- to refer to pointers in GHCi's address space.
-- They are initialized in 'GHC.HsToCore.Breakpoints.mkModBreaks', called by
-- 'GHC.HsToCore.deSugar'.
--
-- Breakpoints might be disabled because we're in TH, because
-- @-fno-break-points@ was specified, or because a module was reloaded without
-- reinitializing 'ModBreaks'.
---- If the module stored in the breakpoint is the currently processed module, use
-- the 'ModBreaks' from the state.
-- If that is 'Nothing', consider breakpoints to be disabled and skip the
-- instruction.
--
-- If the breakpoint is inlined from another module, look it up in the home
-- package table.
-- If the module doesn't exist there, or its module pointer is null (which means
-- that the 'ModBreaks' value is uninitialized), skip the instruction.
break_info ::
HscEnv ->
Module ->
Module ->
Maybe ModBreaks ->
Maybe ModBreaks
break_info hsc_env mod current_mod current_mod_breaks
| mod == current_mod
= check_mod_ptr =<< current_mod_breaks
| Just hp <- lookupHpt (hsc_HPT hsc_env) (moduleName mod)
= check_mod_ptr (getModBreaks hp)
| otherwise
= Nothing
where
check_mod_ptr mb
| mod_ptr <- modBreaks_module mb
, fromRemotePtr mod_ptr /= nullPtr
= Just mb
| otherwise
= Nothing
getVarOffSets :: Platform -> StackDepth -> BCEnv -> [Id] -> [Maybe (Id, WordOff)]
getVarOffSets platform depth env = map getOffSet
where
getOffSet id = case lookupBCEnv_maybe id env of
Nothing -> Nothing
Just offset ->
-- michalt: I'm not entirely sure why we need the stack
-- adjustment by 2 here. I initially thought that there's
-- something off with getIdValFromApStack (the only user of this
-- value), but it looks ok to me. My current hypothesis is that
-- this "adjustment" is needed due to stack manipulation for
-- BRK_FUN in Interpreter.c In any case, this is used only when
-- we trigger a breakpoint.
let !var_depth_ws = bytesToWords platform (depth - offset) + 2
in Just (id, var_depth_ws)
fvsToEnv :: BCEnv -> CgStgRhs -> [Id]
-- Takes the free variables of a right-hand side, and
-- delivers an ordered list of the local variables that will
-- be captured in the thunk for the RHS
-- The BCEnv argument tells which variables are in the local
-- environment: these are the ones that should be captured
--
-- The code that constructs the thunk, and the code that executes
-- it, have to agree about this layout
fvsToEnv p rhs = [v | v <- dVarSetElems $ freeVarsOfRhs rhs,
v `Map.member` p]
-- -----------------------------------------------------------------------------
-- schemeE
-- Returning an unlifted value.
-- Heave it on the stack, SLIDE, and RETURN.
returnUnliftedAtom
:: StackDepth
-> Sequel
-> BCEnv
-> StgArg
-> BcM BCInstrListreturnUnliftedAtom d s p e = do
let reps = stgArgRep e
(push, szb) <- pushAtom d p e
ret <- returnUnliftedReps d s szb reps
return (push `appOL` ret)
-- return an unlifted value from the top of the stack
returnUnliftedReps
:: StackDepth
-> Sequel
-> ByteOff -- size of the thing we're returning
-> [PrimRep] -- representations
-> BcM BCInstrList
returnUnliftedReps d s szb reps = do
profile <- getProfile
let platform = profilePlatform profile
ret <- case reps of
-- use RETURN for nullary/unary representations
[] -> return (unitOL $ RETURN V)
[rep] -> return (unitOL $ RETURN (toArgRep platform rep))
-- otherwise use RETURN_TUPLE with a tuple descriptor
nv_reps -> do
let (call_info, args_offsets) = layoutNativeCall profile NativeTupleReturn 0 (primRepCmmType platform) nv_reps
tuple_bco <- emitBc (tupleBCO platform call_info args_offsets)
return $ PUSH_UBX (mkNativeCallInfoLit platform call_info) 1 `consOL`
PUSH_BCO tuple_bco `consOL`
unitOL RETURN_TUPLE
return ( mkSlideB platform szb (d - s) -- clear to sequel
`consOL` ret) -- go
-- construct and return an unboxed tuple
returnUnboxedTuple
:: StackDepth
-> Sequel
-> BCEnv
-> [StgArg]
-> BcM BCInstrList
returnUnboxedTuple d s p es = do
profile <- getProfile
let platform = profilePlatform profile
arg_ty e = primRepCmmType platform (atomPrimRep e)
(call_info, tuple_components) = layoutNativeCall profile
NativeTupleReturn
d
arg_ty
es
go _ pushes [] = return (reverse pushes)
go !dd pushes ((a, off):cs) = do (push, szb) <- pushAtom dd p a
massert (off == dd + szb)
go (dd + szb) (push:pushes) cs
pushes <- go d [] tuple_components
let non_void VoidRep = False
non_void _ = True
ret <- returnUnliftedReps d
s
(wordsToBytes platform $ nativeCallSize call_info)
(filter non_void $ map atomPrimRep es)
return (mconcat pushes `appOL` ret)
-- Compile code to apply the given expression to the remaining args
-- on the stack, returning a HNF.
schemeE
:: StackDepth -> Sequel -> BCEnv -> CgStgExpr -> BcM BCInstrList
schemeE d s p (StgLit lit) = returnUnliftedAtom d s p (StgLitArg lit)
schemeE d s p (StgApp x [])
| isUnliftedType (idType x) = returnUnliftedAtom d s p (StgVarArg x)
-- Delegate tail-calls to schemeT.
schemeE d s p e@(StgApp {}) = schemeT d s p e
schemeE d s p e@(StgConApp {}) = schemeT d s p e
schemeE d s p e@(StgOpApp {}) = schemeT d s p eschemeE d s p (StgLetNoEscape xlet bnd body)
= schemeE d s p (StgLet xlet bnd body)
schemeE d s p (StgLet _xlet
(StgNonRec x (StgRhsCon _cc data_con _cnum _ticks args _typ))
body)
= do -- Special case for a non-recursive let whose RHS is a
-- saturated constructor application.
-- Just allocate the constructor and carry on
alloc_code <- mkConAppCode d s p data_con args
platform <- targetPlatform <$> getDynFlags
let !d2 = d + wordSize platform
body_code <- schemeE d2 s (Map.insert x d2 p) body
return (alloc_code `appOL` body_code)
-- General case for let. Generates correct, if inefficient, code in
-- all situations.
schemeE d s p (StgLet _ext binds body) = do
platform <- targetPlatform <$> getDynFlags
let (xs,rhss) = case binds of StgNonRec x rhs -> ([x],[rhs])
StgRec xs_n_rhss -> unzip xs_n_rhss
n_binds = genericLength xs
fvss = map (fvsToEnv p') rhss
-- Sizes of free vars
size_w = idSizeW platform
sizes = map (\rhs_fvs -> sum (map size_w rhs_fvs)) fvss
-- the arity of each rhs
arities = map (genericLength . fst . collect) rhss
-- This p', d' defn is safe because all the items being pushed
-- are ptrs, so all have size 1 word. d' and p' reflect the stack
-- after the closures have been allocated in the heap (but not
-- filled in), and pointers to them parked on the stack.
offsets = mkStackOffsets d (genericReplicate n_binds (wordSize platform))
p' = Map.insertList (zipE xs offsets) p
d' = d + wordsToBytes platform n_binds
zipE = zipEqual "schemeE"
-- ToDo: don't build thunks for things with no free variables
build_thunk
:: StackDepth
-> [Id]
-> WordOff
-> ProtoBCO Name
-> WordOff
-> HalfWord
-> BcM BCInstrList
build_thunk _ [] size bco off arity
= return (PUSH_BCO bco `consOL` unitOL (mkap (off+size) (fromIntegral size)))
where
mkap | arity == 0 = MKAP
| otherwise = MKPAP
build_thunk dd (fv:fvs) size bco off arity = do
(push_code, pushed_szb) <- pushAtom dd p' (StgVarArg fv)
more_push_code <-
build_thunk (dd + pushed_szb) fvs size bco off arity
return (push_code `appOL` more_push_code)
alloc_code = toOL (zipWith mkAlloc sizes arities)
where mkAlloc sz 0
| is_tick = ALLOC_AP_NOUPD (fromIntegral sz)
| otherwise = ALLOC_AP (fromIntegral sz)
mkAlloc sz arity = ALLOC_PAP arity (fromIntegral sz)
is_tick = case binds of
StgNonRec id _ -> occNameFS (getOccName id) == tickFS
_other -> False
compile_bind d' fvs x (rhs::CgStgRhs) size arity off = do bco <- schemeR fvs (getName x,rhs)
build_thunk d' fvs size bco off arity
compile_binds =
[ compile_bind d' fvs x rhs size arity n
| (fvs, x, rhs, size, arity, n) <-
zip6 fvss xs rhss sizes arities [n_binds, n_binds-1 .. 1]
]
body_code <- schemeE d' s p' body
thunk_codes <- sequence compile_binds
return (alloc_code `appOL` concatOL thunk_codes `appOL` body_code)
schemeE _d _s _p (StgTick (Breakpoint _ bp_id _ _) _rhs)
= panic ("schemeE: Breakpoint without let binding: " ++
show bp_id ++
" forgot to run bcPrep?")
-- ignore other kinds of tick
schemeE d s p (StgTick _ rhs) = schemeE d s p rhs
-- no alts: scrut is guaranteed to diverge
schemeE d s p (StgCase scrut _ _ []) = schemeE d s p scrut
schemeE d s p (StgCase scrut bndr _ alts)
= doCase d s p scrut bndr alts
{-
Ticked Expressions
------------------
The idea is that the "breakpoint<n,fvs> E" is really just an annotation on
the code. When we find such a thing, we pull out the useful information,
and then compile the code as if it was just the expression E.
-}
-- Compile code to do a tail call. Specifically, push the fn,
-- slide the on-stack app back down to the sequel depth,
-- and enter. Four cases:
--
-- 0. (Nasty hack).
-- An application "GHC.Prim.tagToEnum# <type> unboxed-int".
-- The int will be on the stack. Generate a code sequence
-- to convert it to the relevant constructor, SLIDE and ENTER.
--
-- 1. The fn denotes a ccall. Defer to generateCCall.
--
-- 2. An unboxed tuple: push the components on the top of
-- the stack and return.
--
-- 3. Application of a constructor, by defn saturated.
-- Split the args into ptrs and non-ptrs, and push the nonptrs,
-- then the ptrs, and then do PACK and RETURN.
--
-- 4. Otherwise, it must be a function call. Push the args
-- right to left, SLIDE and ENTER.
schemeT :: StackDepth -- Stack depth
-> Sequel -- Sequel depth
-> BCEnv -- stack env
-> CgStgExpr
-> BcM BCInstrList
-- Case 0
schemeT d s p app
| Just (arg, constr_names) <- maybe_is_tagToEnum_call app
= implement_tagToId d s p arg constr_names
-- Case 1
schemeT d s p (StgOpApp (StgFCallOp (CCall ccall_spec) _ty) args result_ty) = if isSupportedCConv ccall_spec
then generateCCall d s p ccall_spec result_ty args
else unsupportedCConvException
schemeT d s p (StgOpApp (StgPrimOp op) args _ty)
= doTailCall d s p (primOpId op) (reverse args)
schemeT d s p (StgOpApp (StgPrimCallOp (PrimCall label unit)) args result_ty)
= generatePrimCall d s p label (Just unit) result_ty args
schemeT d s p (StgConApp con _cn args _tys)
-- Case 2: Unboxed tuple
| isUnboxedTupleDataCon con || isUnboxedSumDataCon con
= returnUnboxedTuple d s p args
-- Case 3: Ordinary data constructor
| otherwise
= do alloc_con <- mkConAppCode d s p con args
platform <- profilePlatform <$> getProfile
return (alloc_con `appOL`
mkSlideW 1 (bytesToWords platform $ d - s) `snocOL` RETURN P)
-- Case 4: Tail call of function
schemeT d s p (StgApp fn args)
= doTailCall d s p fn (reverse args)
schemeT _ _ _ e = pprPanic "GHC.StgToByteCode.schemeT"
(pprStgExpr shortStgPprOpts e)
-- -----------------------------------------------------------------------------
-- Generate code to build a constructor application,
-- leaving it on top of the stack
mkConAppCode
:: StackDepth
-> Sequel
-> BCEnv
-> DataCon -- The data constructor
-> [StgArg] -- Args, in *reverse* order
-> BcM BCInstrList
mkConAppCode orig_d _ p con args = app_code
where
app_code = do
profile <- getProfile
let platform = profilePlatform profile
non_voids =
[ NonVoid (prim_rep, arg)
| arg <- args
, let prim_rep = atomPrimRep arg
, not (isVoidRep prim_rep)
]
(_, _, args_offsets) =
mkVirtHeapOffsetsWithPadding profile StdHeader non_voids
do_pushery !d (arg : args) = do
(push, arg_bytes) <- case arg of
(Padding l _) -> return $! pushPadding (ByteOff l)
(FieldOff a _) -> pushConstrAtom d p (fromNonVoid a)
more_push_code <- do_pushery (d + arg_bytes) args
return (push `appOL` more_push_code)
do_pushery !d [] = do
let !n_arg_words = bytesToWords platform (d - orig_d)
return (unitOL (PACK con n_arg_words))
-- Push on the stack in the reverse order.
do_pushery orig_d (reverse args_offsets)
-- -----------------------------------------------------------------------------
-- Generate code for a tail-call
doTailCall
:: StackDepth
-> Sequel
-> BCEnv
-> Id
-> [StgArg]
-> BcM BCInstrList
doTailCall init_d s p fn args = do
platform <- profilePlatform <$> getProfile
do_pushes init_d args (map (atomRep platform) args)
where
do_pushes !d [] reps = do
assert (null reps) return ()
(push_fn, sz) <- pushAtom d p (StgVarArg fn)
platform <- profilePlatform <$> getProfile
assert (sz == wordSize platform) return ()
let slide = mkSlideB platform (d - init_d + wordSize platform) (init_d - s)
return (push_fn `appOL` (slide `consOL` unitOL ENTER))
do_pushes !d args reps = do
let (push_apply, n, rest_of_reps) = findPushSeq reps
(these_args, rest_of_args) = splitAt n args
(next_d, push_code) <- push_seq d these_args
platform <- profilePlatform <$> getProfile
instrs <- do_pushes (next_d + wordSize platform) rest_of_args rest_of_reps
-- ^^^ for the PUSH_APPLY_ instruction
return (push_code `appOL` (push_apply `consOL` instrs))
push_seq d [] = return (d, nilOL)
push_seq d (arg:args) = do
(push_code, sz) <- pushAtom d p arg
(final_d, more_push_code) <- push_seq (d + sz) args
return (final_d, push_code `appOL` more_push_code)
-- v. similar to CgStackery.findMatch, ToDo: merge
findPushSeq :: [ArgRep] -> (BCInstr, Int, [ArgRep])
findPushSeq (P: P: P: P: P: P: rest)
= (PUSH_APPLY_PPPPPP, 6, rest)
findPushSeq (P: P: P: P: P: rest)
= (PUSH_APPLY_PPPPP, 5, rest)
findPushSeq (P: P: P: P: rest)
= (PUSH_APPLY_PPPP, 4, rest)
findPushSeq (P: P: P: rest)
= (PUSH_APPLY_PPP, 3, rest)
findPushSeq (P: P: rest)
= (PUSH_APPLY_PP, 2, rest)
findPushSeq (P: rest)
= (PUSH_APPLY_P, 1, rest)
findPushSeq (V: rest)
= (PUSH_APPLY_V, 1, rest)
findPushSeq (N: rest)
= (PUSH_APPLY_N, 1, rest)
findPushSeq (F: rest)
= (PUSH_APPLY_F, 1, rest)
findPushSeq (D: rest)
= (PUSH_APPLY_D, 1, rest)
findPushSeq (L: rest)
= (PUSH_APPLY_L, 1, rest)
findPushSeq argReps
| any (`elem` [V16, V32, V64]) argReps
= sorry "SIMD vector operations are not available in GHCi"
findPushSeq _
= panic "GHC.StgToByteCode.findPushSeq"
-- -----------------------------------------------------------------------------
-- Case expressions
doCase
:: StackDepth
-> Sequel -> BCEnv
-> CgStgExpr
-> Id
-> [CgStgAlt]
-> BcM BCInstrList
doCase d s p scrut bndr alts
= do
profile <- getProfile
hsc_env <- getHscEnv
let
platform = profilePlatform profile
-- Are we dealing with an unboxed tuple with a tuple return frame?
--
-- 'Simple' tuples with at most one non-void component,
-- like (# Word# #) or (# Int#, State# RealWorld #) do not have a
-- tuple return frame. This is because (# foo #) and (# foo, Void# #)
-- have the same runtime rep. We have more efficient specialized
-- return frames for the situations with one non-void element.
non_void_arg_reps = typeArgReps platform bndr_ty
ubx_tuple_frame =
(isUnboxedTupleType bndr_ty || isUnboxedSumType bndr_ty) &&
length non_void_arg_reps > 1
profiling
| Just interp <- hsc_interp hsc_env
= interpreterProfiled interp
| otherwise = False
-- Top of stack is the return itbl, as usual.
-- underneath it is the pointer to the alt_code BCO.
-- When an alt is entered, it assumes the returned value is
-- on top of the itbl; see Note [Return convention for non-tuple values]
-- for details.
ret_frame_size_b :: StackDepth
ret_frame_size_b | ubx_tuple_frame =
(if profiling then 5 else 4) * wordSize platform
| otherwise = 2 * wordSize platform
-- The stack space used to save/restore the CCCS when profiling
save_ccs_size_b | profiling &&
not ubx_tuple_frame = 2 * wordSize platform
| otherwise = 0
-- The size of the return frame info table pointer if one exists
unlifted_itbl_size_b :: StackDepth
unlifted_itbl_size_b | ubx_tuple_frame = wordSize platform
| otherwise = 0
(bndr_size, call_info, args_offsets)
| ubx_tuple_frame =
let bndr_ty = primRepCmmType platform
bndr_reps = typePrimRep (idType bndr)
(call_info, args_offsets) =
layoutNativeCall profile NativeTupleReturn 0 bndr_ty bndr_reps
in ( wordsToBytes platform (nativeCallSize call_info)
, call_info
, args_offsets
)
| otherwise = ( wordsToBytes platform (idSizeW platform bndr)
, voidTupleReturnInfo
, []
)
-- depth of stack after the return value has been pushed
d_bndr =
d + ret_frame_size_b + bndr_size
-- depth of stack after the extra info table for an unlifted return -- has been pushed, if any. This is the stack depth at the
-- continuation.
d_alts = d + ret_frame_size_b + bndr_size + unlifted_itbl_size_b
-- Env in which to compile the alts, not including
-- any vars bound by the alts themselves
p_alts = Map.insert bndr d_bndr p
bndr_ty = idType bndr
isAlgCase = isAlgType bndr_ty
-- given an alt, return a discr and code for it.
codeAlt :: CgStgAlt -> BcM (Discr, BCInstrList)
codeAlt GenStgAlt{alt_con=DEFAULT,alt_bndrs=_,alt_rhs=rhs}
= do rhs_code <- schemeE d_alts s p_alts rhs
return (NoDiscr, rhs_code)
codeAlt alt@GenStgAlt{alt_con=_, alt_bndrs=bndrs, alt_rhs=rhs}
-- primitive or nullary constructor alt: no need to UNPACK
| null real_bndrs = do
rhs_code <- schemeE d_alts s p_alts rhs
return (my_discr alt, rhs_code)
| isUnboxedTupleType bndr_ty || isUnboxedSumType bndr_ty =
let bndr_ty = primRepCmmType platform . bcIdPrimRep
tuple_start = d_bndr
(call_info, args_offsets) =
layoutNativeCall profile
NativeTupleReturn
0
bndr_ty
bndrs
stack_bot = d_alts
p' = Map.insertList
[ (arg, tuple_start -
wordsToBytes platform (nativeCallSize call_info) +
offset)
| (arg, offset) <- args_offsets
, not (isVoidRep $ bcIdPrimRep arg)]
p_alts
in do
rhs_code <- schemeE stack_bot s p' rhs
return (NoDiscr, rhs_code)
-- algebraic alt with some binders
| otherwise =
let (tot_wds, _ptrs_wds, args_offsets) =
mkVirtHeapOffsets profile NoHeader
[ NonVoid (bcIdPrimRep id, id)
| NonVoid id <- nonVoidIds real_bndrs
]
size = WordOff tot_wds
stack_bot = d_alts + wordsToBytes platform size
-- convert offsets from Sp into offsets into the virtual stack
p' = Map.insertList
[ (arg, stack_bot - ByteOff offset)
| (NonVoid arg, offset) <- args_offsets ]
p_alts
in do
massert isAlgCase
rhs_code <- schemeE stack_bot s p' rhs
return (my_discr alt,
unitOL (UNPACK size) `appOL` rhs_code)
where
real_bndrs = filterOut isTyVar bndrs
my_discr alt = case alt_con alt of DEFAULT -> NoDiscr {-shouldn't really happen-}
DataAlt dc
| isUnboxedTupleDataCon dc || isUnboxedSumDataCon dc
-> NoDiscr
| otherwise
-> DiscrP (fromIntegral (dataConTag dc - fIRST_TAG))
LitAlt l -> case l of
LitNumber LitNumInt i -> DiscrI (fromInteger i)
LitNumber LitNumInt8 i -> DiscrI8 (fromInteger i)
LitNumber LitNumInt16 i -> DiscrI16 (fromInteger i)
LitNumber LitNumInt32 i -> DiscrI32 (fromInteger i)
LitNumber LitNumInt64 i -> DiscrI64 (fromInteger i)
LitNumber LitNumWord w -> DiscrW (fromInteger w)
LitNumber LitNumWord8 w -> DiscrW8 (fromInteger w)
LitNumber LitNumWord16 w -> DiscrW16 (fromInteger w)
LitNumber LitNumWord32 w -> DiscrW32 (fromInteger w)
LitNumber LitNumWord64 w -> DiscrW64 (fromInteger w)
LitNumber LitNumBigNat _ -> unsupported
LitFloat r -> DiscrF (fromRational r)
LitDouble r -> DiscrD (fromRational r)
LitChar i -> DiscrI (ord i)
LitString {} -> unsupported
LitRubbish {} -> unsupported
LitNullAddr {} -> unsupported
LitLabel {} -> unsupported
where
unsupported = pprPanic "schemeE(StgCase).my_discr:" (ppr l)
maybe_ncons
| not isAlgCase = Nothing
| otherwise
= case [dc | DataAlt dc <- alt_con <$> alts] of
[] -> Nothing
(dc:_) -> Just (tyConFamilySize (dataConTyCon dc))
-- the bitmap is relative to stack depth d, i.e. before the
-- BCO, info table and return value are pushed on.
-- This bit of code is v. similar to buildLivenessMask in CgBindery,
-- except that here we build the bitmap from the known bindings of
-- things that are pointers, whereas in CgBindery the code builds the
-- bitmap from the free slots and unboxed bindings.
-- (ToDo: merge?)
--
-- NOTE [7/12/2006] bug #1013, testcase ghci/should_run/ghci002.
-- The bitmap must cover the portion of the stack up to the sequel only.
-- Previously we were building a bitmap for the whole depth (d), but we
-- really want a bitmap up to depth (d-s). This affects compilation of
-- case-of-case expressions, which is the only time we can be compiling a
-- case expression with s /= 0.
-- unboxed tuples get two more words, the second is a pointer (tuple_bco)
(extra_pointers, extra_slots)
| ubx_tuple_frame && profiling = ([1], 3) -- call_info, tuple_BCO, CCCS
| ubx_tuple_frame = ([1], 2) -- call_info, tuple_BCO
| otherwise = ([], 0)
bitmap_size :: WordOff
bitmap_size = fromIntegral extra_slots +
bytesToWords platform (d - s)
bitmap_size' :: Int
bitmap_size' = fromIntegral bitmap_size
pointers =
extra_pointers ++
filter (< bitmap_size') (map (+extra_slots) rel_slots)
where
-- NB: unboxed tuple cases bind the scrut binder to the same offset
-- as one of the alt binders, so we have to remove any duplicates here: -- 'toAscList' takes care of sorting the result, which was previously done after the application of 'filter'.
rel_slots = IntSet.toAscList $ IntSet.fromList $ Map.elems $ Map.mapMaybeWithKey spread p
spread id offset | isUnboxedTupleType (idType id) ||
isUnboxedSumType (idType id) = Nothing
| isFollowableArg (bcIdArgRep platform id) = Just (fromIntegral rel_offset)
| otherwise = Nothing
where rel_offset = bytesToWords platform (d - offset)
bitmap = intsToReverseBitmap platform bitmap_size' pointers
alt_stuff <- mapM codeAlt alts
alt_final0 <- mkMultiBranch maybe_ncons alt_stuff
let alt_final
| ubx_tuple_frame = SLIDE 0 2 `consOL` alt_final0
| otherwise = alt_final0
let
alt_bco_name = getName bndr
alt_bco = mkProtoBCO platform alt_bco_name alt_final (Left alts)
0{-no arity-} bitmap_size bitmap True{-is alts-}
scrut_code <- schemeE (d + ret_frame_size_b + save_ccs_size_b)
(d + ret_frame_size_b + save_ccs_size_b)
p scrut
alt_bco' <- emitBc alt_bco
if ubx_tuple_frame
then do tuple_bco <- emitBc (tupleBCO platform call_info args_offsets)
return (PUSH_ALTS_TUPLE alt_bco' call_info tuple_bco
`consOL` scrut_code)
else let scrut_rep = case non_void_arg_reps of
[] -> V
[rep] -> rep
_ -> panic "schemeE(StgCase).push_alts"
in return (PUSH_ALTS alt_bco' scrut_rep `consOL` scrut_code)
-- -----------------------------------------------------------------------------
-- Deal with tuples
-- The native calling convention uses registers for tuples, but in the
-- bytecode interpreter, all values live on the stack.
layoutNativeCall :: Profile
-> NativeCallType
-> ByteOff
-> (a -> CmmType)
-> [a]
-> ( NativeCallInfo -- See Note [GHCi TupleInfo]
, [(a, ByteOff)] -- argument, offset on stack
)
layoutNativeCall profile call_type start_off arg_ty reps =
let platform = profilePlatform profile
(orig_stk_bytes, pos) = assignArgumentsPos profile
0
NativeReturn
arg_ty
reps
-- keep the stack parameters in the same place
orig_stk_params = [(x, fromIntegral off) | (x, StackParam off) <- pos]
-- sort the register parameters by register and add them to the stack
regs_order :: Map.Map GlobalReg Int
regs_order = Map.fromList $ zip (allArgRegsCover platform) [0..]
reg_order :: GlobalReg -> (Int, GlobalReg)
reg_order reg | Just n <- Map.lookup reg regs_order = (n, reg)
-- if we don't have a position for a FloatReg then they must be passed
-- in the equivalent DoubleReg
reg_order (FloatReg n) = reg_order (DoubleReg n) -- one-tuples can be passed in other registers, but then we don't need
-- to care about the order
reg_order reg = (0, reg)
(regs, reg_params)
= unzip $ sortBy (comparing fst)
[(reg_order reg, x) | (x, RegisterParam reg) <- pos]
(new_stk_bytes, new_stk_params) = assignStack platform
orig_stk_bytes
arg_ty
reg_params
regs_set = mkRegSet (map snd regs)
get_byte_off (x, StackParam y) = (x, fromIntegral y)
get_byte_off _ =
panic "GHC.StgToByteCode.layoutTuple get_byte_off"
in ( NativeCallInfo
{ nativeCallType = call_type
, nativeCallSize = bytesToWords platform (ByteOff new_stk_bytes)
, nativeCallRegs = regs_set
, nativeCallStackSpillSize = bytesToWords platform
(ByteOff orig_stk_bytes)
}
, sortBy (comparing snd) $
map (\(x, o) -> (x, o + start_off))
(orig_stk_params ++ map get_byte_off new_stk_params)
)
{- Note [Return convention for non-tuple values]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The RETURN and ENTER instructions are used to return values. RETURN directly
returns the value at the top of the stack while ENTER evaluates it first (so
RETURN is only used when the result is already known to be evaluated), but the
end result is the same: control returns to the enclosing stack frame with the
result at the top of the stack.
The PUSH_ALTS instruction pushes a two-word stack frame that receives a single
lifted value. Its payload is a BCO that is executed when control returns, with
the stack set up as if a RETURN instruction had just been executed: the returned
value is at the top of the stack, and beneath it is the two-word frame being
returned to. It is the continuation BCO’s job to pop its own frame off the
stack, so the simplest possible continuation consists of two instructions:
SLIDE 1 2 -- pop the return frame off the stack, keeping the returned value
RETURN P -- return the returned value to our caller
RETURN and PUSH_ALTS are not really instructions but are in fact representation-
polymorphic *families* of instructions indexed by ArgRep. ENTER, however, is a
single real instruction, since it is only used to return lifted values, which
are always pointers.
The RETURN, ENTER, and PUSH_ALTS instructions are only used when the returned
value has nullary or unary representation. Returning/receiving an unboxed
tuple (or, indirectly, an unboxed sum, since unboxed sums have been desugared to
unboxed tuples by Unarise) containing two or more results uses the special
RETURN_TUPLE/PUSH_ALTS_TUPLE instructions, which use a different return
convention. See Note [unboxed tuple bytecodes and tuple_BCO] for details.
Note [unboxed tuple bytecodes and tuple_BCO]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We have the bytecode instructions RETURN_TUPLE and PUSH_ALTS_TUPLE to
return and receive arbitrary unboxed tuples, respectively. These
instructions use the helper data tuple_BCO and call_info.
The helper data is used to convert tuples between GHCs native calling
convention (object code), which uses stack and registers, and the bytecode
calling convention, which only uses the stack. See Note [GHCi TupleInfo] for more details.
Returning a tuple
=================
Bytecode that returns a tuple first pushes all the tuple fields followed
by the appropriate call_info and tuple_BCO onto the stack. It then
executes the RETURN_TUPLE instruction, which causes the interpreter
to push stg_ret_t_info to the top of the stack. The stack (growing down)
then looks as follows:
...
next_frame
tuple_field_1
tuple_field_2
...
tuple_field_n
call_info
tuple_BCO
stg_ret_t_info <- Sp
If next_frame is bytecode, the interpreter will start executing it. If
it's object code, the interpreter jumps back to the scheduler, which in
turn jumps to stg_ret_t. stg_ret_t converts the tuple to the native
calling convention using the description in call_info, and then jumps
to next_frame.
Receiving a tuple
=================
Bytecode that receives a tuple uses the PUSH_ALTS_TUPLE instruction to
push a continuation, followed by jumping to the code that produces the
tuple. The PUSH_ALTS_TUPLE instuction contains three pieces of data:
* cont_BCO: the continuation that receives the tuple
* call_info: see below
* tuple_BCO: see below
The interpreter pushes these onto the stack when the PUSH_ALTS_TUPLE
instruction is executed, followed by stg_ctoi_tN_info, with N depending
on the number of stack words used by the tuple in the GHC native calling
convention. N is derived from call_info.
For example if we expect a tuple with three words on the stack, the stack
looks as follows after PUSH_ALTS_TUPLE:
...
next_frame
cont_free_var_1
cont_free_var_2
...
cont_free_var_n
call_info
tuple_BCO
cont_BCO
stg_ctoi_t3_info <- Sp
If the tuple is returned by object code, stg_ctoi_t3 will deal with
adjusting the stack pointer and converting the tuple to the bytecode
calling convention. See Note [GHCi unboxed tuples stack spills] for more
details.
The tuple_BCO
=============
The tuple_BCO is a helper bytecode object. Its main purpose is describing
the contents of the stack frame containing the tuple for the storage manager. It contains only instructions to immediately return the tuple
that is already on the stack.
The call_info word
===================
The call_info word describes the stack and STG register (e.g. R1..R6,
D1..D6) usage for the tuple. call_info contains enough information to
convert the tuple between the stack-only bytecode and stack+registers
GHC native calling conventions.
See Note [GHCi and native call registers] for more details of how the
data is packed in a single word.
-}
tupleBCO :: Platform -> NativeCallInfo -> [(PrimRep, ByteOff)] -> [FFIInfo] -> ProtoBCO Name
tupleBCO platform args_info args =
mkProtoBCO platform invented_name body_code (Left [])
0{-no arity-} bitmap_size bitmap False{-is alts-}
where
{-
The tuple BCO is never referred to by name, so we can get away
with using a fake name here. We will need to change this if we want
to save some memory by sharing the BCO between places that have
the same tuple shape
-}
invented_name = mkSystemVarName (mkPseudoUniqueE 0) (fsLit "tuple")
-- the first word in the frame is the call_info word,
-- which is not a pointer
nptrs_prefix = 1
(bitmap_size, bitmap) = mkStackBitmap platform nptrs_prefix args_info args
body_code = mkSlideW 0 1 -- pop frame header
`snocOL` RETURN_TUPLE -- and add it again
primCallBCO :: Platform -> NativeCallInfo -> [(PrimRep, ByteOff)] -> [FFIInfo] -> ProtoBCO Name
primCallBCO platform args_info args =
mkProtoBCO platform invented_name body_code (Left [])
0{-no arity-} bitmap_size bitmap False{-is alts-}
where
{-
The primcall BCO is never referred to by name, so we can get away
with using a fake name here. We will need to change this if we want
to save some memory by sharing the BCO between places that have
the same tuple shape
-}
invented_name = mkSystemVarName (mkPseudoUniqueE 0) (fsLit "primcall")
-- The first two words in the frame (after the BCO) are the call_info word
-- and the pointer to the Cmm function being called. Neither of these is a
-- pointer that should be followed by the garbage collector.
nptrs_prefix = 2
(bitmap_size, bitmap) = mkStackBitmap platform nptrs_prefix args_info args
-- if the primcall BCO is ever run it's a bug, since the BCO should only
-- be pushed immediately before running the PRIMCALL bytecode instruction,
-- which immediately leaves the interpreter to jump to the stg_primcall_info
-- Cmm function
body_code = unitOL CASEFAIL
-- | Builds a bitmap for a stack layout with a nonpointer prefix followed by
-- some number of arguments.
mkStackBitmap
:: Platform
-> WordOff
-- ^ The number of nonpointer words that prefix the arguments.
-> NativeCallInfo -> [(PrimRep, ByteOff)]
-- ^ The stack layout of the arguments, where each offset is relative to the
-- /bottom/ of the stack space they occupy. Their offsets must be word-aligned,
-- and the list must be sorted in order of ascending offset (i.e. bottom to top).
-> (WordOff, [StgWord])
mkStackBitmap platform nptrs_prefix args_info args
= (bitmap_size, bitmap)
where
bitmap_size = nptrs_prefix + arg_bottom
bitmap = intsToReverseBitmap platform (fromIntegral bitmap_size) ptr_offsets
arg_bottom = nativeCallSize args_info
ptr_offsets = reverse $ map (fromIntegral . convert_arg_offset)
$ mapMaybe get_ptr_offset args
get_ptr_offset :: (PrimRep, ByteOff) -> Maybe ByteOff
get_ptr_offset (rep, byte_offset)
| isFollowableArg (toArgRep platform rep) = Just byte_offset
| otherwise = Nothing
convert_arg_offset :: ByteOff -> WordOff
convert_arg_offset arg_offset =
-- The argument offsets are relative to `arg_bottom`, but
-- `intsToReverseBitmap` expects offsets from the top, so we need to flip
-- them around.
nptrs_prefix + (arg_bottom - bytesToWords platform arg_offset)
-- -----------------------------------------------------------------------------
-- Deal with a primitive call to native code.
generatePrimCall
:: StackDepth
-> Sequel
-> BCEnv
-> CLabelString -- where to call
-> Maybe Unit
-> Type
-> [StgArg] -- args (atoms)
-> BcM BCInstrList
generatePrimCall d s p target _mb_unit _result_ty args
= do
profile <- getProfile
let
platform = profilePlatform profile
non_void VoidRep = False
non_void _ = True
nv_args :: [StgArg]
nv_args = filter (non_void . stgArgRep1) args
(args_info, args_offsets) =
layoutNativeCall profile
NativePrimCall
0
(primRepCmmType platform . stgArgRep1)
nv_args
prim_args_offsets = mapFst stgArgRep1 args_offsets
shifted_args_offsets = mapSnd (+ d) args_offsets
push_target = PUSH_UBX (LitLabel target Nothing IsFunction) 1
push_info = PUSH_UBX (mkNativeCallInfoLit platform args_info) 1
{-
compute size to move payload (without stg_primcall_info header)
size of arguments plus three words for:
- function pointer to the target
- call_info word
- BCO to describe the stack frame -}
szb = wordsToBytes platform (nativeCallSize args_info + 3)
go _ pushes [] = return (reverse pushes)
go !dd pushes ((a, off):cs) = do (push, szb) <- pushAtom dd p a
massert (off == dd + szb)
go (dd + szb) (push:pushes) cs
push_args <- go d [] shifted_args_offsets
args_bco <- emitBc (primCallBCO platform args_info prim_args_offsets)
return $ mconcat push_args `appOL`
(push_target `consOL`
push_info `consOL`
PUSH_BCO args_bco `consOL`
(mkSlideB platform szb (d - s) `consOL` unitOL PRIMCALL))
-- -----------------------------------------------------------------------------
-- Deal with a CCall.
-- Taggedly push the args onto the stack R->L,
-- deferencing ForeignObj#s and adjusting addrs to point to
-- payloads in Ptr/Byte arrays. Then, generate the marshalling
-- (machine) code for the ccall, and create bytecodes to call that and
-- then return in the right way.
generateCCall
:: StackDepth
-> Sequel
-> BCEnv
-> CCallSpec -- where to call
-> Type
-> [StgArg] -- args (atoms)
-> BcM BCInstrList
generateCCall d0 s p (CCallSpec target PrimCallConv _) result_ty args
| (StaticTarget _ label mb_unit _) <- target
= generatePrimCall d0 s p label mb_unit result_ty args
| otherwise
= panic "GHC.StgToByteCode.generateCCall: primcall convention only supports static targets"
generateCCall d0 s p (CCallSpec target cconv safety) result_ty args
= do
profile <- getProfile
let
args_r_to_l = reverse args
platform = profilePlatform profile
-- useful constants
addr_size_b :: ByteOff
addr_size_b = wordSize platform
arrayish_rep_hdr_size :: TyCon -> Maybe Int
arrayish_rep_hdr_size t
| t == arrayPrimTyCon || t == mutableArrayPrimTyCon
= Just (arrPtrsHdrSize profile)
| t == smallArrayPrimTyCon || t == smallMutableArrayPrimTyCon
= Just (smallArrPtrsHdrSize profile)
| t == byteArrayPrimTyCon || t == mutableByteArrayPrimTyCon
= Just (arrWordsHdrSize profile)
| otherwise
= Nothing
-- Get the args on the stack, with tags and suitably
-- dereferenced for the CCall. For each arg, return the
-- depth to the first word of the bits for that arg, and the
-- ArgRep of what was actually pushed.
pargs
:: ByteOff -> [StgArg] -> BcM [(BCInstrList, PrimRep)]
pargs _ [] = return []
pargs d (aa@(StgVarArg a):az)
| Just t <- tyConAppTyCon_maybe (idType a)
, Just hdr_sz <- arrayish_rep_hdr_size t
-- Do magic for Ptr/Byte arrays. Push a ptr to the array on -- the stack but then advance it over the headers, so as to
-- point to the payload.
= do rest <- pargs (d + addr_size_b) az
(push_fo, _) <- pushAtom d p aa
-- The ptr points at the header. Advance it over the
-- header and then pretend this is an Addr#.
let code = push_fo `snocOL` SWIZZLE 0 (fromIntegral hdr_sz)
return ((code, AddrRep) : rest)
pargs d (aa:az) = do (code_a, sz_a) <- pushAtom d p aa
rest <- pargs (d + sz_a) az
return ((code_a, atomPrimRep aa) : rest)
code_n_reps <- pargs d0 args_r_to_l
let
(pushs_arg, a_reps_pushed_r_to_l) = unzip code_n_reps
a_reps_sizeW = sum (map (repSizeWords platform) a_reps_pushed_r_to_l)
push_args = concatOL pushs_arg
!d_after_args = d0 + wordsToBytes platform a_reps_sizeW
a_reps_pushed_RAW
| x:xs <- a_reps_pushed_r_to_l
, isVoidRep x
= reverse xs
| otherwise
= panic "GHC.StgToByteCode.generateCCall: missing or invalid World token?"
-- Now: a_reps_pushed_RAW are the reps which are actually on the stack.
-- push_args is the code to do that.
-- d_after_args is the stack depth once the args are on.
-- Get the result rep.
(returns_void, r_rep)
= case maybe_getCCallReturnRep result_ty of
Nothing -> (True, VoidRep)
Just rr -> (False, rr)
{-
Because the Haskell stack grows down, the a_reps refer to
lowest to highest addresses in that order. The args for the call
are on the stack. Now push an unboxed Addr# indicating
the C function to call. Then push a dummy placeholder for the
result. Finally, emit a CCALL insn with an offset pointing to the
Addr# just pushed, and a literal field holding the mallocville
address of the piece of marshalling code we generate.
So, just prior to the CCALL insn, the stack looks like this
(growing down, as usual):
<arg_n>
...
<arg_1>
Addr# address_of_C_fn
<placeholder-for-result#> (must be an unboxed type)
The interpreter then calls the marshal code mentioned
in the CCALL insn, passing it (& <placeholder-for-result#>),
that is, the addr of the topmost word in the stack.
When this returns, the placeholder will have been
filled in. The placeholder is slid down to the sequel
depth, and we RETURN.
This arrangement makes it simple to do f-i-dynamic since the Addr#
value is the first arg anyway.
The marshalling code is generated specifically for this
call site, and so knows exactly the (Haskell) stack
offsets of the args, fn address and placeholder. It
copies the args to the C stack, calls the stacked addr,
and parks the result back in the placeholder. The interpreter
calls it as a normal C call, assuming it has a signature
void marshal_code ( StgWord* ptr_to_top_of_stack )
-} -- resolve static address
maybe_static_target :: Maybe Literal
maybe_static_target =
case target of
DynamicTarget -> Nothing
StaticTarget _ _ _ False ->
panic "generateCCall: unexpected FFI value import"
StaticTarget _ target _ True ->
Just (LitLabel target mb_size IsFunction)
where
mb_size
| OSMinGW32 <- platformOS platform
, StdCallConv <- cconv
= Just (fromIntegral a_reps_sizeW * platformWordSizeInBytes platform)
| otherwise
= Nothing
let
is_static = isJust maybe_static_target
-- Get the arg reps, zapping the leading Addr# in the dynamic case
a_reps -- | trace (showSDoc (ppr a_reps_pushed_RAW)) False = error "???"
| is_static = a_reps_pushed_RAW
| _:xs <- a_reps_pushed_RAW = xs
| otherwise = panic "GHC.StgToByteCode.generateCCall: dyn with no args"
-- push the Addr#
(push_Addr, d_after_Addr)
| Just machlabel <- maybe_static_target
= (toOL [PUSH_UBX machlabel 1], d_after_args + addr_size_b)
| otherwise -- is already on the stack
= (nilOL, d_after_args)
-- Push the return placeholder. For a call returning nothing,
-- this is a V (tag).
r_sizeW = repSizeWords platform r_rep
d_after_r = d_after_Addr + wordsToBytes platform r_sizeW
push_r =
if returns_void
then nilOL
else unitOL (PUSH_UBX (mkDummyLiteral platform r_rep) (r_sizeW))
-- generate the marshalling code we're going to call
-- Offset of the next stack frame down the stack. The CCALL
-- instruction needs to describe the chunk of stack containing
-- the ccall args to the GC, so it needs to know how large it
-- is. See comment in Interpreter.c with the CCALL instruction.
stk_offset = bytesToWords platform (d_after_r - s)
conv = case cconv of
CCallConv -> FFICCall
CApiConv -> FFICCall
StdCallConv -> FFIStdCall
_ -> panic "GHC.StgToByteCode: unexpected calling convention"
-- the only difference in libffi mode is that we prepare a cif
-- describing the call type by calling libffi, and we attach the
-- address of this to the CCALL instruction.
let ffires = primRepToFFIType platform r_rep
ffiargs = map (primRepToFFIType platform) a_reps
interp <- hscInterp <$> getHscEnv
token <- ioToBc $ interpCmd interp (PrepFFI conv ffiargs ffires)
recordFFIBc token
let
-- do the call
do_call = unitOL (CCALL stk_offset token flags) where flags = case safety of
PlaySafe -> 0x0
PlayInterruptible -> 0x1
PlayRisky -> 0x2
-- slide and return
d_after_r_min_s = bytesToWords platform (d_after_r - s)
wrapup = mkSlideW r_sizeW (d_after_r_min_s - r_sizeW)
`snocOL` RETURN (toArgRep platform r_rep)
--trace (show (arg1_offW, args_offW , (map argRepSizeW a_reps) )) $
return (
push_args `appOL`
push_Addr `appOL` push_r `appOL` do_call `appOL` wrapup
)
primRepToFFIType :: Platform -> PrimRep -> FFIType
primRepToFFIType platform r
= case r of
VoidRep -> FFIVoid
IntRep -> signed_word
WordRep -> unsigned_word
Int8Rep -> FFISInt8
Word8Rep -> FFIUInt8
Int16Rep -> FFISInt16
Word16Rep -> FFIUInt16
Int32Rep -> FFISInt32
Word32Rep -> FFIUInt32
Int64Rep -> FFISInt64
Word64Rep -> FFIUInt64
AddrRep -> FFIPointer
FloatRep -> FFIFloat
DoubleRep -> FFIDouble
BoxedRep _ -> FFIPointer
_ -> pprPanic "primRepToFFIType" (ppr r)
where
(signed_word, unsigned_word) = case platformWordSize platform of
PW4 -> (FFISInt32, FFIUInt32)
PW8 -> (FFISInt64, FFIUInt64)
-- Make a dummy literal, to be used as a placeholder for FFI return
-- values on the stack.
mkDummyLiteral :: Platform -> PrimRep -> Literal
mkDummyLiteral platform pr
= case pr of
IntRep -> mkLitInt platform 0
WordRep -> mkLitWord platform 0
Int8Rep -> mkLitInt8 0
Word8Rep -> mkLitWord8 0
Int16Rep -> mkLitInt16 0
Word16Rep -> mkLitWord16 0
Int32Rep -> mkLitInt32 0
Word32Rep -> mkLitWord32 0
Int64Rep -> mkLitInt64 0
Word64Rep -> mkLitWord64 0
AddrRep -> LitNullAddr
DoubleRep -> LitDouble 0
FloatRep -> LitFloat 0
BoxedRep _ -> LitNullAddr
_ -> pprPanic "mkDummyLiteral" (ppr pr)
-- Convert (eg)
-- GHC.Prim.Char# -> GHC.Prim.State# GHC.Prim.RealWorld
-- -> (# GHC.Prim.State# GHC.Prim.RealWorld, GHC.Prim.Int# #)
--
-- to Just IntRep
-- and check that an unboxed pair is returned wherein the first arg is V'd.
--
-- Alternatively, for call-targets returning nothing, convert
---- GHC.Prim.Char# -> GHC.Prim.State# GHC.Prim.RealWorld
-- -> (# GHC.Prim.State# GHC.Prim.RealWorld #)
--
-- to Nothing
maybe_getCCallReturnRep :: Type -> Maybe PrimRep
maybe_getCCallReturnRep fn_ty
= let
(_a_tys, r_ty) = splitFunTys (dropForAlls fn_ty)
in
case typePrimRep r_ty of
[] -> Nothing
[rep] -> Just rep
-- if it was, it would be impossible to create a
-- valid return value placeholder on the stack
_ -> pprPanic "maybe_getCCallReturn: can't handle:"
(pprType fn_ty)
maybe_is_tagToEnum_call :: CgStgExpr -> Maybe (Id, [Name])
-- Detect and extract relevant info for the tagToEnum kludge.
maybe_is_tagToEnum_call (StgOpApp (StgPrimOp TagToEnumOp) [StgVarArg v] t)
= Just (v, extract_constr_Names t)
where
extract_constr_Names ty
| rep_ty <- unwrapType ty
, Just tyc <- tyConAppTyCon_maybe rep_ty
, isDataTyCon tyc
= map (getName . dataConWorkId) (tyConDataCons tyc)
-- NOTE: use the worker name, not the source name of
-- the DataCon. See "GHC.Core.DataCon" for details.
| otherwise
= pprPanic "maybe_is_tagToEnum_call.extract_constr_Ids" (ppr ty)
maybe_is_tagToEnum_call _ = Nothing
{- -----------------------------------------------------------------------------
Note [Implementing tagToEnum#]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(implement_tagToId arg names) compiles code which takes an argument
'arg', (call it i), and enters the i'th closure in the supplied list
as a consequence. The [Name] is a list of the constructors of this
(enumeration) type.
The code we generate is this:
push arg
TESTEQ_I 0 L1
PUSH_G <lbl for first data con>
JMP L_Exit
L1: TESTEQ_I 1 L2
PUSH_G <lbl for second data con>
JMP L_Exit
...etc...
Ln: TESTEQ_I n L_fail
PUSH_G <lbl for last data con>
JMP L_Exit
L_fail: CASEFAIL
L_exit: SLIDE 1 n
ENTER
-}
implement_tagToId
:: StackDepth
-> Sequel
-> BCEnv
-> Id -> [Name]
-> BcM BCInstrList
-- See Note [Implementing tagToEnum#]
implement_tagToId d s p arg names
= assert (notNull names) $
do (push_arg, arg_bytes) <- pushAtom d p (StgVarArg arg)
labels <- getLabelsBc (genericLength names)
label_fail <- getLabelBc
label_exit <- getLabelBc
dflags <- getDynFlags
let infos = zip4 labels (tail labels ++ [label_fail])
[0 ..] names
platform = targetPlatform dflags
steps = map (mkStep label_exit) infos
slide_ws = bytesToWords platform (d - s + arg_bytes)
return (push_arg
`appOL` concatOL steps
`appOL` toOL [ LABEL label_fail, CASEFAIL,
LABEL label_exit ]
`appOL` mkSlideW 1 slide_ws
`appOL` unitOL ENTER)
where
mkStep l_exit (my_label, next_label, n, name_for_n)
= toOL [LABEL my_label,
TESTEQ_I n next_label,
PUSH_G name_for_n,
JMP l_exit]
-- -----------------------------------------------------------------------------
-- pushAtom
-- Push an atom onto the stack, returning suitable code & number of
-- stack words used.
--
-- The env p must map each variable to the highest- numbered stack
-- slot for it. For example, if the stack has depth 4 and we
-- tagged-ly push (v :: Int#) on it, the value will be in stack[4],
-- the tag in stack[5], the stack will have depth 6, and p must map v
-- to 5 and not to 4. Stack locations are numbered from zero, so a
-- depth 6 stack has valid words 0 .. 5.
pushAtom
:: StackDepth -> BCEnv -> StgArg -> BcM (BCInstrList, ByteOff)
-- See Note [Empty case alternatives] in GHC.Core
-- and Note [Bottoming expressions] in GHC.Core.Utils:
-- The scrutinee of an empty case evaluates to bottom
pushAtom d p (StgVarArg var)
| [] <- typePrimRep (idType var)
= return (nilOL, 0)
| isFCallId var
= pprPanic "pushAtom: shouldn't get an FCallId here" (ppr var)
| Just primop <- isPrimOpId_maybe var
= do
platform <- targetPlatform <$> getDynFlags
return (unitOL (PUSH_PRIMOP primop), wordSize platform)
| Just d_v <- lookupBCEnv_maybe var p -- var is a local variable
= do platform <- targetPlatform <$> getDynFlags
let !szb = idSizeCon platform var
with_instr :: (ByteOff -> BCInstr) -> BcM (OrdList BCInstr, ByteOff)
with_instr instr = do
let !off_b = d - d_v
return (unitOL (instr off_b), wordSize platform)
case szb of
1 -> with_instr PUSH8_W
2 -> with_instr PUSH16_W
4 -> with_instr PUSH32_W
_ -> do
let !szw = bytesToWords platform szb
!off_w = bytesToWords platform (d - d_v) + szw - 1
return (toOL (genericReplicate szw (PUSH_L off_w)),
wordsToBytes platform szw)
-- d - d_v offset from TOS to the first slot of the object
--
-- d - d_v + sz - 1 offset from the TOS of the last slot of the object
--
-- Having found the last slot, we proceed to copy the right number of
-- slots on to the top of the stack.
| otherwise -- var must be a global variable
= do platform <- targetPlatform <$> getDynFlags
let !szb = idSizeCon platform var
massert (szb == wordSize platform)
-- PUSH_G doesn't tag constructors. So we use PACK here
-- if we are dealing with nullary constructor.
case isDataConWorkId_maybe var of
Just con -> do
massert (isNullaryRepDataCon con)
return (unitOL (PACK con 0), szb)
Nothing
-- see Note [Generating code for top-level string literal bindings]
| isUnliftedType (idType var) -> do
massert (idType var `eqType` addrPrimTy)
return (unitOL (PUSH_ADDR (getName var)), szb)
| otherwise -> do
return (unitOL (PUSH_G (getName var)), szb)
pushAtom _ _ (StgLitArg lit) = pushLiteral True lit
pushLiteral :: Bool -> Literal -> BcM (BCInstrList, ByteOff)
pushLiteral padded lit =
do
platform <- targetPlatform <$> getDynFlags
let code :: PrimRep -> BcM (BCInstrList, ByteOff)
code rep =
return (padding_instr `snocOL` instr, size_bytes + padding_bytes)
where
size_bytes = ByteOff $ primRepSizeB platform rep
-- Here we handle the non-word-width cases specifically since we
-- must emit different bytecode for them.
round_to_words (ByteOff bytes) =
ByteOff (roundUpToWords platform bytes)
padding_bytes
| padded = round_to_words size_bytes - size_bytes
| otherwise = 0
(padding_instr, _) = pushPadding padding_bytes
instr =
case size_bytes of
1 -> PUSH_UBX8 lit
2 -> PUSH_UBX16 lit
4 -> PUSH_UBX32 lit
_ -> PUSH_UBX lit (bytesToWords platform size_bytes)
case lit of LitLabel {} -> code AddrRep
LitFloat {} -> code FloatRep
LitDouble {} -> code DoubleRep
LitChar {} -> code WordRep
LitNullAddr -> code AddrRep
LitString {} -> code AddrRep
LitRubbish _ rep-> case runtimeRepPrimRep (text "pushLiteral") rep of
[pr] -> code pr
_ -> pprPanic "pushLiteral" (ppr lit)
LitNumber nt _ -> case nt of
LitNumInt -> code IntRep
LitNumWord -> code WordRep
LitNumInt8 -> code Int8Rep
LitNumWord8 -> code Word8Rep
LitNumInt16 -> code Int16Rep
LitNumWord16 -> code Word16Rep
LitNumInt32 -> code Int32Rep
LitNumWord32 -> code Word32Rep
LitNumInt64 -> code Int64Rep
LitNumWord64 -> code Word64Rep
-- No LitNumBigNat should be left by the time this is called. CorePrep
-- should have converted them all to a real core representation.
LitNumBigNat -> panic "pushAtom: LitNumBigNat"
-- | Push an atom for constructor (i.e., PACK instruction) onto the stack.
-- This is slightly different to @pushAtom@ due to the fact that we allow
-- packing constructor fields. See also @mkConAppCode@ and @pushPadding@.
pushConstrAtom
:: StackDepth -> BCEnv -> StgArg -> BcM (BCInstrList, ByteOff)
pushConstrAtom _ _ (StgLitArg lit) = pushLiteral False lit
pushConstrAtom d p va@(StgVarArg v)
| Just d_v <- lookupBCEnv_maybe v p = do -- v is a local variable
platform <- targetPlatform <$> getDynFlags
let !szb = idSizeCon platform v
done instr = do
let !off = d - d_v
return (unitOL (instr off), szb)
case szb of
1 -> done PUSH8
2 -> done PUSH16
4 -> done PUSH32
_ -> pushAtom d p va
pushConstrAtom d p expr = pushAtom d p expr
pushPadding :: ByteOff -> (BCInstrList, ByteOff)
pushPadding (ByteOff n) = go n (nilOL, 0)
where
go n acc@(!instrs, !off) = case n of
0 -> acc
1 -> (instrs `mappend` unitOL PUSH_PAD8, off + 1)
2 -> (instrs `mappend` unitOL PUSH_PAD16, off + 2)
3 -> go 1 (go 2 acc)
4 -> (instrs `mappend` unitOL PUSH_PAD32, off + 4)
_ -> go (n - 4) (go 4 acc)
-- -----------------------------------------------------------------------------
-- Given a bunch of alts code and their discrs, do the donkey work
-- of making a multiway branch using a switch tree.
-- What a load of hassle!
mkMultiBranch :: Maybe Int -- # datacons in tycon, if alg alt
-- a hint; generates better code
-- Nothing is always safe
-> [(Discr, BCInstrList)]
-> BcM BCInstrList
mkMultiBranch maybe_ncons raw_ways = do
lbl_default <- getLabelBc
let
mkTree :: [(Discr, BCInstrList)] -> Discr -> Discr -> BcM BCInstrList
mkTree [] _range_lo _range_hi = return (unitOL (JMP lbl_default))
-- shouldn't happen?
mkTree [val] range_lo range_hi
| range_lo == range_hi
= return (snd val)
| null defaults -- Note [CASEFAIL]
= do lbl <- getLabelBc
return (testEQ (fst val) lbl
`consOL` (snd val
`appOL` (LABEL lbl `consOL` unitOL CASEFAIL)))
| otherwise
= return (testEQ (fst val) lbl_default `consOL` snd val)
-- Note [CASEFAIL]
-- ~~~~~~~~~~~~~~~
-- It may be that this case has no default
-- branch, but the alternatives are not exhaustive - this
-- happens for GADT cases for example, where the types
-- prove that certain branches are impossible. We could
-- just assume that the other cases won't occur, but if
-- this assumption was wrong (because of a bug in GHC)
-- then the result would be a segfault. So instead we
-- emit an explicit test and a CASEFAIL instruction that
-- causes the interpreter to barf() if it is ever
-- executed.
mkTree vals range_lo range_hi
= let n = length vals `div` 2
(vals_lo, vals_hi) = splitAt n vals
v_mid = fst (head vals_hi)
in do
label_geq <- getLabelBc
code_lo <- mkTree vals_lo range_lo (dec v_mid)
code_hi <- mkTree vals_hi v_mid range_hi
return (testLT v_mid label_geq
`consOL` (code_lo
`appOL` unitOL (LABEL label_geq)
`appOL` code_hi))
the_default
= case defaults of
[] -> nilOL
[(_, def)] -> LABEL lbl_default `consOL` def
_ -> panic "mkMultiBranch/the_default"
instrs <- mkTree notd_ways init_lo init_hi
return (instrs `appOL` the_default)
where
(defaults, not_defaults) = partition (isNoDiscr.fst) raw_ways
notd_ways = sortBy (comparing fst) not_defaults
testLT (DiscrI i) fail_label = TESTLT_I i fail_label
testLT (DiscrI8 i) fail_label = TESTLT_I8 (fromIntegral i) fail_label
testLT (DiscrI16 i) fail_label = TESTLT_I16 (fromIntegral i) fail_label
testLT (DiscrI32 i) fail_label = TESTLT_I32 (fromIntegral i) fail_label
testLT (DiscrI64 i) fail_label = TESTLT_I64 (fromIntegral i) fail_label
testLT (DiscrW i) fail_label = TESTLT_W i fail_label
testLT (DiscrW8 i) fail_label = TESTLT_W8 (fromIntegral i) fail_label
testLT (DiscrW16 i) fail_label = TESTLT_W16 (fromIntegral i) fail_label
testLT (DiscrW32 i) fail_label = TESTLT_W32 (fromIntegral i) fail_label
testLT (DiscrW64 i) fail_label = TESTLT_W64 (fromIntegral i) fail_label
testLT (DiscrF i) fail_label = TESTLT_F i fail_label
testLT (DiscrD i) fail_label = TESTLT_D i fail_label
testLT (DiscrP i) fail_label = TESTLT_P i fail_label
testLT NoDiscr _ = panic "mkMultiBranch NoDiscr"
testEQ (DiscrI i) fail_label = TESTEQ_I i fail_label
testEQ (DiscrI8 i) fail_label = TESTEQ_I8 (fromIntegral i) fail_label testEQ (DiscrI16 i) fail_label = TESTEQ_I16 (fromIntegral i) fail_label
testEQ (DiscrI32 i) fail_label = TESTEQ_I32 (fromIntegral i) fail_label
testEQ (DiscrI64 i) fail_label = TESTEQ_I64 (fromIntegral i) fail_label
testEQ (DiscrW i) fail_label = TESTEQ_W i fail_label
testEQ (DiscrW8 i) fail_label = TESTEQ_W8 (fromIntegral i) fail_label
testEQ (DiscrW16 i) fail_label = TESTEQ_W16 (fromIntegral i) fail_label
testEQ (DiscrW32 i) fail_label = TESTEQ_W32 (fromIntegral i) fail_label
testEQ (DiscrW64 i) fail_label = TESTEQ_W64 (fromIntegral i) fail_label
testEQ (DiscrF i) fail_label = TESTEQ_F i fail_label
testEQ (DiscrD i) fail_label = TESTEQ_D i fail_label
testEQ (DiscrP i) fail_label = TESTEQ_P i fail_label
testEQ NoDiscr _ = panic "mkMultiBranch NoDiscr"
-- None of these will be needed if there are no non-default alts
(init_lo, init_hi) = case notd_ways of
[] -> panic "mkMultiBranch: awesome foursome"
(discr, _):_ -> case discr of
DiscrI _ -> ( DiscrI minBound, DiscrI maxBound )
DiscrI8 _ -> ( DiscrI8 minBound, DiscrI8 maxBound )
DiscrI16 _ -> ( DiscrI16 minBound, DiscrI16 maxBound )
DiscrI32 _ -> ( DiscrI32 minBound, DiscrI32 maxBound )
DiscrI64 _ -> ( DiscrI64 minBound, DiscrI64 maxBound )
DiscrW _ -> ( DiscrW minBound, DiscrW maxBound )
DiscrW8 _ -> ( DiscrW8 minBound, DiscrW8 maxBound )
DiscrW16 _ -> ( DiscrW16 minBound, DiscrW16 maxBound )
DiscrW32 _ -> ( DiscrW32 minBound, DiscrW32 maxBound )
DiscrW64 _ -> ( DiscrW64 minBound, DiscrW64 maxBound )
DiscrF _ -> ( DiscrF minF, DiscrF maxF )
DiscrD _ -> ( DiscrD minD, DiscrD maxD )
DiscrP _ -> ( DiscrP algMinBound, DiscrP algMaxBound )
NoDiscr -> panic "mkMultiBranch NoDiscr"
(algMinBound, algMaxBound)
= case maybe_ncons of
-- XXX What happens when n == 0?
Just n -> (0, fromIntegral n - 1)
Nothing -> (minBound, maxBound)
isNoDiscr NoDiscr = True
isNoDiscr _ = False
dec (DiscrI i) = DiscrI (i-1)
dec (DiscrW w) = DiscrW (w-1)
dec (DiscrP i) = DiscrP (i-1)
dec other = other -- not really right, but if you
-- do cases on floating values, you'll get what you deserve
-- same snotty comment applies to the following
minF, maxF :: Float
minD, maxD :: Double
minF = -1.0e37
maxF = 1.0e37
minD = -1.0e308
maxD = 1.0e308
-- -----------------------------------------------------------------------------
-- Supporting junk for the compilation schemes
-- Describes case alts
data Discr
= DiscrI Int
| DiscrI8 Int8
| DiscrI16 Int16
| DiscrI32 Int32
| DiscrI64 Int64
| DiscrW Word
| DiscrW8 Word8
| DiscrW16 Word16
| DiscrW32 Word32 | DiscrW64 Word64
| DiscrF Float
| DiscrD Double
| DiscrP Word16
| NoDiscr
deriving (Eq, Ord)
instance Outputable Discr where
ppr (DiscrI i) = int i
ppr (DiscrI8 i) = text (show i)
ppr (DiscrI16 i) = text (show i)
ppr (DiscrI32 i) = text (show i)
ppr (DiscrI64 i) = text (show i)
ppr (DiscrW w) = text (show w)
ppr (DiscrW8 w) = text (show w)
ppr (DiscrW16 w) = text (show w)
ppr (DiscrW32 w) = text (show w)
ppr (DiscrW64 w) = text (show w)
ppr (DiscrF f) = text (show f)
ppr (DiscrD d) = text (show d)
ppr (DiscrP i) = ppr i
ppr NoDiscr = text "DEF"
lookupBCEnv_maybe :: Id -> BCEnv -> Maybe ByteOff
lookupBCEnv_maybe = Map.lookup
idSizeW :: Platform -> Id -> WordOff
idSizeW platform = WordOff . argRepSizeW platform . bcIdArgRep platform
idSizeCon :: Platform -> Id -> ByteOff
idSizeCon platform var
-- unboxed tuple components are padded to word size
| isUnboxedTupleType (idType var) ||
isUnboxedSumType (idType var) =
wordsToBytes platform .
WordOff . sum . map (argRepSizeW platform . toArgRep platform) .
typePrimRep . idType $ var
| otherwise = ByteOff (primRepSizeB platform (bcIdPrimRep var))
bcIdArgRep :: Platform -> Id -> ArgRep
bcIdArgRep platform = toArgRep platform . bcIdPrimRep
bcIdPrimRep :: Id -> PrimRep
bcIdPrimRep id
| rep :| [] <- typePrimRepArgs (idType id)
= rep
| otherwise
= pprPanic "bcIdPrimRep" (ppr id <+> dcolon <+> ppr (idType id))
repSizeWords :: Platform -> PrimRep -> WordOff
repSizeWords platform rep = WordOff $ argRepSizeW platform (toArgRep platform rep)
isFollowableArg :: ArgRep -> Bool
isFollowableArg P = True
isFollowableArg _ = False
-- | Indicate if the calling convention is supported
isSupportedCConv :: CCallSpec -> Bool
isSupportedCConv (CCallSpec _ cconv _) = case cconv of
CCallConv -> True -- we explicitly pattern match on every
StdCallConv -> True -- convention to ensure that a warning
PrimCallConv -> True -- is triggered when a new one is added
JavaScriptCallConv -> False
CApiConv -> True
-- See bug #10462
unsupportedCConvException :: a
unsupportedCConvException = throwGhcException (ProgramError
("Error: bytecode compiler can't handle some foreign calling conventions\n"++ " Workaround: use -fobject-code, or compile this module to .o separately."))
mkSlideB :: Platform -> ByteOff -> ByteOff -> BCInstr
mkSlideB platform nb db = SLIDE n d
where
!n = bytesToWords platform nb
!d = bytesToWords platform db
mkSlideW :: WordOff -> WordOff -> OrdList BCInstr
mkSlideW !n !ws
| ws == 0
= nilOL
| otherwise
= unitOL (SLIDE n $ fromIntegral ws)
atomPrimRep :: StgArg -> PrimRep
atomPrimRep (StgVarArg v) = bcIdPrimRep v
atomPrimRep (StgLitArg l) = typePrimRep1 (literalType l)
atomRep :: Platform -> StgArg -> ArgRep
atomRep platform e = toArgRep platform (atomPrimRep e)
-- | Let szsw be the sizes in bytes of some items pushed onto the stack, which
-- has initial depth @original_depth@. Return the values which the stack
-- environment should map these items to.
mkStackOffsets :: ByteOff -> [ByteOff] -> [ByteOff]
mkStackOffsets original_depth szsb = tail (scanl' (+) original_depth szsb)
typeArgReps :: Platform -> Type -> [ArgRep]
typeArgReps platform = map (toArgRep platform) . typePrimRep
-- -----------------------------------------------------------------------------
-- The bytecode generator's monad
data BcM_State
= BcM_State
{ bcm_hsc_env :: HscEnv
, thisModule :: Module -- current module (for breakpoints)
, nextlabel :: Word32 -- for generating local labels
, ffis :: [FFIInfo] -- ffi info blocks, to free later
-- Should be free()d when it is GCd
, modBreaks :: Maybe ModBreaks -- info about breakpoints
, breakInfo :: IntMap CgBreakInfo
}
newtype BcM r = BcM (BcM_State -> IO (BcM_State, r)) deriving (Functor)
ioToBc :: IO a -> BcM a
ioToBc io = BcM $ \st -> do
x <- io
return (st, x)
runBc :: HscEnv -> Module -> Maybe ModBreaks
-> BcM r
-> IO (BcM_State, r)
runBc hsc_env this_mod modBreaks (BcM m)
= m (BcM_State hsc_env this_mod 0 [] modBreaks IntMap.empty)
thenBc :: BcM a -> (a -> BcM b) -> BcM b
thenBc (BcM expr) cont = BcM $ \st0 -> do
(st1, q) <- expr st0
let BcM k = cont q
(st2, r) <- k st1
return (st2, r)
thenBc_ :: BcM a -> BcM b -> BcM b
thenBc_ (BcM expr) (BcM cont) = BcM $ \st0 -> do
(st1, _) <- expr st0 (st2, r) <- cont st1
return (st2, r)
returnBc :: a -> BcM a
returnBc result = BcM $ \st -> (return (st, result))
instance Applicative BcM where
pure = returnBc
(<*>) = ap
(*>) = thenBc_
instance Monad BcM where
(>>=) = thenBc
(>>) = (*>)
instance HasDynFlags BcM where
getDynFlags = BcM $ \st -> return (st, hsc_dflags (bcm_hsc_env st))
getHscEnv :: BcM HscEnv
getHscEnv = BcM $ \st -> return (st, bcm_hsc_env st)
getProfile :: BcM Profile
getProfile = targetProfile <$> getDynFlags
emitBc :: ([FFIInfo] -> ProtoBCO Name) -> BcM (ProtoBCO Name)
emitBc bco
= BcM $ \st -> return (st{ffis=[]}, bco (ffis st))
recordFFIBc :: RemotePtr C_ffi_cif -> BcM ()
recordFFIBc a
= BcM $ \st -> return (st{ffis = FFIInfo a : ffis st}, ())
getLabelBc :: BcM LocalLabel
getLabelBc
= BcM $ \st -> do let nl = nextlabel st
when (nl == maxBound) $
panic "getLabelBc: Ran out of labels"
return (st{nextlabel = nl + 1}, LocalLabel nl)
getLabelsBc :: Word32 -> BcM [LocalLabel]
getLabelsBc n
= BcM $ \st -> let ctr = nextlabel st
in return (st{nextlabel = ctr+n}, coerce [ctr .. ctr+n-1])
getCCArray :: BcM (Array BreakIndex (RemotePtr CostCentre))
getCCArray = BcM $ \st ->
let breaks = expectJust "GHC.StgToByteCode.getCCArray" $ modBreaks st in
return (st, modBreaks_ccs breaks)
newBreakInfo :: BreakIndex -> CgBreakInfo -> BcM ()
newBreakInfo ix info = BcM $ \st ->
return (st{breakInfo = IntMap.insert ix info (breakInfo st)}, ())
getCurrentModule :: BcM Module
getCurrentModule = BcM $ \st -> return (st, thisModule st)
getCurrentModBreaks :: BcM (Maybe ModBreaks)
getCurrentModBreaks = BcM $ \st -> return (st, modBreaks st)
tickFS :: FastString
tickFS = fsLit "ticked"