ghc-9.14.1: GHC/StgToByteCode.hs
{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE DerivingVia #-}
--
-- (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.Reg ( GlobalArgRegs(..) )
import GHC.Cmm.Node
import GHC.Cmm.Utils
import GHC.Platform
import GHC.Platform.Profile
import GHCi.FFI
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.Predicate( tyCoVarsOfTypesWellScoped )
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.CmmToAsm.Config (platformWordWidth)
import GHC.StgToCmm.Closure ( NonVoid(..), fromNonVoid, idPrimRepU,
addIdReps, addArgReps,
assertNonVoidIds, assertNonVoidStgArgs )
import GHC.StgToCmm.Layout
import GHC.Runtime.Heap.Layout hiding (WordOff, ByteOff, wordsToBytes)
import GHC.Runtime.Interpreter ( interpreterProfiled )
import GHC.Data.Bitmap
import GHC.Data.FlatBag as FlatBag
import GHC.Data.OrdList
import GHC.Data.Maybe
import GHC.Types.Tickish
import GHC.Types.SptEntry
import GHC.ByteCode.Breakpoints
import Data.List ( genericReplicate, intersperse
, partition, scanl', sortBy, zip4, zip6 )
import Foreign hiding (shiftL, shiftR)
import Control.Monad
import Data.Char
import GHC.Unit.Module
import Data.Coerce (coerce)
#if MIN_VERSION_rts(1,0,3)
import qualified Data.ByteString.Char8 as BS
#endif
import Data.Map (Map)
import Data.IntMap (IntMap)
import qualified Data.Map as Map
import qualified Data.IntMap as IntMap
import qualified GHC.Data.FiniteMap as Map
import Data.Ord
import Data.Either ( partitionEithers )
import GHC.Stg.Syntax
import qualified Data.IntSet as IntSet
import GHC.CoreToIface
import Control.Monad.IO.Class
import Control.Monad.Trans.Reader (ReaderT(..))
import Control.Monad.Trans.State (StateT(..))
import Data.Bifunctor (Bifunctor(..))
-- -----------------------------------------------------------------------------
-- Generating byte code for a complete module
byteCodeGen :: HscEnv
-> Module
-> [CgStgTopBinding]
-> [TyCon]
-> Maybe ModBreaks
-> [SptEntry]
-> IO CompiledByteCode
byteCodeGen hsc_env this_mod binds tycs mb_modBreaks spt_entries
= 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 (getName b, str)]
flattenBind (StgNonRec b e) = [(b,e)]
flattenBind (StgRec bs) = bs
(proto_bcos, BcM_State{..}) <-
runBc hsc_env this_mod mb_modBreaks $ do
let flattened_binds = concatMap flattenBind (reverse lifted_binds)
FlatBag.fromList (fromIntegral $ length flattened_binds) <$> mapM schemeTopBind flattened_binds
putDumpFileMaybe logger Opt_D_dump_BCOs
"Proto-BCOs" FormatByteCode
(vcat (intersperse (char ' ') (map ppr $ elemsFlatBag proto_bcos)))
let mod_breaks = case mb_modBreaks of
Nothing -> Nothing
Just mb -> Just $ mkInternalModBreaks this_mod breakInfo mb
cbc <- assembleBCOs profile proto_bcos tycs strings mod_breaks spt_entries
-- 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
profile = targetProfile dflags
{- 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 is not allocated until bytecode link-time, the
bc_strs field of the CompiledByteCode result records [(Name, ByteString)]
directly.
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
-> Maybe Module
-- ^ Just cur_mod <=> label with @BCO_NAME@ instruction
-- see Note [BCO_NAME]
-> Name
-> BCInstrList
-> Either [CgStgAlt] (CgStgRhs)
-- ^ original expression; for debugging only
-> Int -- ^ arity
-> WordOff -- ^ bitmap size
-> [StgWord] -- ^ bitmap
-> Bool -- ^ True <=> it's a case continuation, rather than a function
-- See also Note [Case continuation BCOs].
-> ProtoBCO Name
mkProtoBCO platform _add_bco_name nm instrs_ordlist origin arity bitmap_size bitmap is_ret
= ProtoBCO {
protoBCOName = nm,
protoBCOInstrs = maybe_add_bco_name $ maybe_add_stack_check peep_d,
protoBCOBitmap = bitmap,
protoBCOBitmapSize = fromIntegral bitmap_size,
protoBCOArity = arity,
protoBCOExpr = origin
}
where
#if MIN_VERSION_rts(1,0,3)
maybe_add_bco_name instrs
| Just cur_mod <- _add_bco_name =
let str = BS.pack $ showSDocOneLine defaultSDocContext (pprFullNameWithUnique cur_mod nm)
in BCO_NAME str : instrs
#endif
maybe_add_bco_name instrs = instrs
-- 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_add_stack_check instrs
| is_ret && stack_usage < fromIntegral (pc_AP_STACK_SPLIM (platformConstants platform)) = instrs
-- 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 : instrs
| otherwise
= instrs -- 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
add_bco_name <- shouldAddBcoName
-- 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.
-- liftIO (putStrLn $ "top level BCO")
pure (mkProtoBCO platform add_bco_name
(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.
--
-- The resulting ProtoBCO expects the free variables and the function arguments
-- to be in the stack frame directly before it.
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
add_bco_name <- shouldAddBcoName
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
-- Make a stack offset for each argument or free var -- they should
-- appear contiguous in the stack, in order.
p_init = Map.fromList (zip all_args (mkStackOffsets 0 szsb_args))
-- make the arg bitmap
bits = argBits platform (reverse (map (idArgRep platform) all_args))
bitmap_size = strictGenericLength bits
bitmap = mkBitmap platform bits
body_code <- schemeER_wrk sum_szsb_args p_init body
pure (mkProtoBCO platform add_bco_name 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 bp@(Breakpoint tick_ty tick_id fvs) rhs) = do
platform <- profilePlatform <$> getProfile
-- When we find a tick we update the "last breakpoint location".
-- We use it when constructing step-out BRK_FUNs in doCase
-- See Note [Debugger: Stepout internal break locs]
code <- withBreakTick bp $ schemeE d 0 p rhs
-- As per Note [Stack layout when entering run_BCO], the breakpoint AP_STACK
-- as we yield from the interpreter is headed by a stg_apply_interp + BCO to be a valid stack.
-- Therefore, the var offsets are offset by 2 words
let idOffSets = map (fmap (second (+2))) $
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
(Right tick_id)
mibi <- newBreakInfo breakInfo
return $ case mibi of
Nothing -> code
Just ibi -> BRK_FUN ibi `consOL` code
schemeER_wrk d p rhs = schemeE d 0 p rhs
-- | Get the offset in words into this breakpoint's AP_STACK which contains the matching Id
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 ->
let !var_depth_ws = bytesToWords platform (depth - offset)
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 BCInstrList
returnUnliftedAtom 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 id nv_reps
tuple_bco = 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
`appOL` 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
(call_info, tuple_components) = layoutNativeCall profile
NativeTupleReturn
d
stgArgRepU
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
ret <- returnUnliftedReps d
s
(wordsToBytes platform $ nativeCallSize call_info)
(map stgArgRepU 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 e
schemeE 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 = strictGenericLength 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 (strictGenericLength . 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 (zipEqual xs offsets) p
d' = d + wordsToBytes platform n_binds
-- 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)
= pprPanic "schemeE: Breakpoint without let binding:"
(ppr bp_id <+> text "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) = do
profile <- getProfile
let platform = profilePlatform profile
case doPrimOp platform op d s p args of
-- Can we do this right in the interpreter?
Just prim_code -> prim_code
-- Otherwise we have to do a call to the primop wrapper instead :(
_ -> 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 =
addArgReps (assertNonVoidStgArgs args)
(_, _, 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 tail call only after
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 <$> getProfile
assert (sz == wordSize platform) return ()
let slide = mkSlideB platform (d - init_d + wordSize platform) (init_d - s)
return (push_fn `appOL` (slide `appOL` unitOL ENTER))
do_pushes !d args reps = do
let (push_apply, n, rest_of_reps) = findPushSeq reps
(these_args, rest_of_args) = splitAt n args
(next_d, push_code) <- push_seq d these_args
platform <- profilePlatform <$> 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)
doPrimOp :: Platform
-> PrimOp
-> StackDepth
-> Sequel
-> BCEnv
-> [StgArg]
-> Maybe (BcM BCInstrList)
doPrimOp platform op init_d s p args =
case op of
IntAddOp -> sizedPrimOp OP_ADD
Int64AddOp -> only64bit $ sizedPrimOp OP_ADD
Int32AddOp -> sizedPrimOp OP_ADD
Int16AddOp -> sizedPrimOp OP_ADD
Int8AddOp -> sizedPrimOp OP_ADD
WordAddOp -> sizedPrimOp OP_ADD
Word64AddOp -> only64bit $ sizedPrimOp OP_ADD
Word32AddOp -> sizedPrimOp OP_ADD
Word16AddOp -> sizedPrimOp OP_ADD
Word8AddOp -> sizedPrimOp OP_ADD
AddrAddOp -> sizedPrimOp OP_ADD
IntMulOp -> sizedPrimOp OP_MUL
Int64MulOp -> only64bit $ sizedPrimOp OP_MUL
Int32MulOp -> sizedPrimOp OP_MUL
Int16MulOp -> sizedPrimOp OP_MUL
Int8MulOp -> sizedPrimOp OP_MUL
WordMulOp -> sizedPrimOp OP_MUL
Word64MulOp -> only64bit $ sizedPrimOp OP_MUL
Word32MulOp -> sizedPrimOp OP_MUL
Word16MulOp -> sizedPrimOp OP_MUL
Word8MulOp -> sizedPrimOp OP_MUL
IntSubOp -> sizedPrimOp OP_SUB
WordSubOp -> sizedPrimOp OP_SUB
Int64SubOp -> only64bit $ sizedPrimOp OP_SUB
Int32SubOp -> sizedPrimOp OP_SUB
Int16SubOp -> sizedPrimOp OP_SUB
Int8SubOp -> sizedPrimOp OP_SUB
Word64SubOp -> only64bit $ sizedPrimOp OP_SUB
Word32SubOp -> sizedPrimOp OP_SUB
Word16SubOp -> sizedPrimOp OP_SUB
Word8SubOp -> sizedPrimOp OP_SUB
AddrSubOp -> sizedPrimOp OP_SUB
IntAndOp -> sizedPrimOp OP_AND
WordAndOp -> sizedPrimOp OP_AND
Word64AndOp -> only64bit $ sizedPrimOp OP_AND
Word32AndOp -> sizedPrimOp OP_AND
Word16AndOp -> sizedPrimOp OP_AND
Word8AndOp -> sizedPrimOp OP_AND
IntNotOp -> sizedPrimOp OP_NOT
WordNotOp -> sizedPrimOp OP_NOT
Word64NotOp -> only64bit $ sizedPrimOp OP_NOT
Word32NotOp -> sizedPrimOp OP_NOT
Word16NotOp -> sizedPrimOp OP_NOT
Word8NotOp -> sizedPrimOp OP_NOT
IntXorOp -> sizedPrimOp OP_XOR
WordXorOp -> sizedPrimOp OP_XOR
Word64XorOp -> only64bit $ sizedPrimOp OP_XOR
Word32XorOp -> sizedPrimOp OP_XOR
Word16XorOp -> sizedPrimOp OP_XOR
Word8XorOp -> sizedPrimOp OP_XOR
IntOrOp -> sizedPrimOp OP_OR
WordOrOp -> sizedPrimOp OP_OR
Word64OrOp -> only64bit $ sizedPrimOp OP_OR
Word32OrOp -> sizedPrimOp OP_OR
Word16OrOp -> sizedPrimOp OP_OR
Word8OrOp -> sizedPrimOp OP_OR
WordSllOp -> sizedPrimOp OP_SHL
Word64SllOp -> only64bit $ sizedPrimOp OP_SHL -- check 32bit platform
Word32SllOp -> sizedPrimOp OP_SHL
Word16SllOp -> sizedPrimOp OP_SHL
Word8SllOp -> sizedPrimOp OP_SHL
IntSllOp -> sizedPrimOp OP_SHL
Int64SllOp -> only64bit $ sizedPrimOp OP_SHL
Int32SllOp -> sizedPrimOp OP_SHL
Int16SllOp -> sizedPrimOp OP_SHL
Int8SllOp -> sizedPrimOp OP_SHL
WordSrlOp -> sizedPrimOp OP_LSR
Word64SrlOp -> only64bit $ sizedPrimOp OP_LSR
Word32SrlOp -> sizedPrimOp OP_LSR
Word16SrlOp -> sizedPrimOp OP_LSR
Word8SrlOp -> sizedPrimOp OP_LSR
IntSrlOp -> sizedPrimOp OP_LSR
Int64SrlOp -> only64bit $ sizedPrimOp OP_LSR -- check 32bit platform
Int32SrlOp -> sizedPrimOp OP_LSR
Int16SrlOp -> sizedPrimOp OP_LSR
Int8SrlOp -> sizedPrimOp OP_LSR
IntSraOp -> sizedPrimOp OP_ASR
Int64SraOp -> only64bit $ sizedPrimOp OP_ASR -- check 32bit platform
Int32SraOp -> sizedPrimOp OP_ASR
Int16SraOp -> sizedPrimOp OP_ASR
Int8SraOp -> sizedPrimOp OP_ASR
IntNeOp -> sizedPrimOp OP_NEQ
Int64NeOp -> only64bit $ sizedPrimOp OP_NEQ
Int32NeOp -> sizedPrimOp OP_NEQ
Int16NeOp -> sizedPrimOp OP_NEQ
Int8NeOp -> sizedPrimOp OP_NEQ
WordNeOp -> sizedPrimOp OP_NEQ
Word64NeOp -> only64bit $ sizedPrimOp OP_NEQ
Word32NeOp -> sizedPrimOp OP_NEQ
Word16NeOp -> sizedPrimOp OP_NEQ
Word8NeOp -> sizedPrimOp OP_NEQ
AddrNeOp -> sizedPrimOp OP_NEQ
IntEqOp -> sizedPrimOp OP_EQ
Int64EqOp -> only64bit $ sizedPrimOp OP_EQ
Int32EqOp -> sizedPrimOp OP_EQ
Int16EqOp -> sizedPrimOp OP_EQ
Int8EqOp -> sizedPrimOp OP_EQ
WordEqOp -> sizedPrimOp OP_EQ
Word64EqOp -> only64bit $ sizedPrimOp OP_EQ
Word32EqOp -> sizedPrimOp OP_EQ
Word16EqOp -> sizedPrimOp OP_EQ
Word8EqOp -> sizedPrimOp OP_EQ
AddrEqOp -> sizedPrimOp OP_EQ
CharEqOp -> sizedPrimOp OP_EQ
IntLtOp -> sizedPrimOp OP_S_LT
Int64LtOp -> only64bit $ sizedPrimOp OP_S_LT
Int32LtOp -> sizedPrimOp OP_S_LT
Int16LtOp -> sizedPrimOp OP_S_LT
Int8LtOp -> sizedPrimOp OP_S_LT
WordLtOp -> sizedPrimOp OP_U_LT
Word64LtOp -> only64bit $ sizedPrimOp OP_U_LT
Word32LtOp -> sizedPrimOp OP_U_LT
Word16LtOp -> sizedPrimOp OP_U_LT
Word8LtOp -> sizedPrimOp OP_U_LT
AddrLtOp -> sizedPrimOp OP_U_LT
CharLtOp -> sizedPrimOp OP_U_LT
IntGeOp -> sizedPrimOp OP_S_GE
Int64GeOp -> only64bit $ sizedPrimOp OP_S_GE
Int32GeOp -> sizedPrimOp OP_S_GE
Int16GeOp -> sizedPrimOp OP_S_GE
Int8GeOp -> sizedPrimOp OP_S_GE
WordGeOp -> sizedPrimOp OP_U_GE
Word64GeOp -> only64bit $ sizedPrimOp OP_U_GE
Word32GeOp -> sizedPrimOp OP_U_GE
Word16GeOp -> sizedPrimOp OP_U_GE
Word8GeOp -> sizedPrimOp OP_U_GE
AddrGeOp -> sizedPrimOp OP_U_GE
CharGeOp -> sizedPrimOp OP_U_GE
IntGtOp -> sizedPrimOp OP_S_GT
Int64GtOp -> only64bit $ sizedPrimOp OP_S_GT
Int32GtOp -> sizedPrimOp OP_S_GT
Int16GtOp -> sizedPrimOp OP_S_GT
Int8GtOp -> sizedPrimOp OP_S_GT
WordGtOp -> sizedPrimOp OP_U_GT
Word64GtOp -> only64bit $ sizedPrimOp OP_U_GT
Word32GtOp -> sizedPrimOp OP_U_GT
Word16GtOp -> sizedPrimOp OP_U_GT
Word8GtOp -> sizedPrimOp OP_U_GT
AddrGtOp -> sizedPrimOp OP_U_GT
CharGtOp -> sizedPrimOp OP_U_GT
IntLeOp -> sizedPrimOp OP_S_LE
Int64LeOp -> only64bit $ sizedPrimOp OP_S_LE
Int32LeOp -> sizedPrimOp OP_S_LE
Int16LeOp -> sizedPrimOp OP_S_LE
Int8LeOp -> sizedPrimOp OP_S_LE
WordLeOp -> sizedPrimOp OP_U_LE
Word64LeOp -> only64bit $ sizedPrimOp OP_U_LE
Word32LeOp -> sizedPrimOp OP_U_LE
Word16LeOp -> sizedPrimOp OP_U_LE
Word8LeOp -> sizedPrimOp OP_U_LE
AddrLeOp -> sizedPrimOp OP_U_LE
CharLeOp -> sizedPrimOp OP_U_LE
IntNegOp -> sizedPrimOp OP_NEG
Int64NegOp -> only64bit $ sizedPrimOp OP_NEG
Int32NegOp -> sizedPrimOp OP_NEG
Int16NegOp -> sizedPrimOp OP_NEG
Int8NegOp -> sizedPrimOp OP_NEG
IntToWordOp -> mk_conv (platformWordWidth platform)
WordToIntOp -> mk_conv (platformWordWidth platform)
Int8ToWord8Op -> mk_conv W8
Word8ToInt8Op -> mk_conv W8
Int16ToWord16Op -> mk_conv W16
Word16ToInt16Op -> mk_conv W16
Int32ToWord32Op -> mk_conv W32
Word32ToInt32Op -> mk_conv W32
Int64ToWord64Op -> only64bit $ mk_conv W64
Word64ToInt64Op -> only64bit $ mk_conv W64
IntToAddrOp -> mk_conv (platformWordWidth platform)
AddrToIntOp -> mk_conv (platformWordWidth platform)
ChrOp -> mk_conv (platformWordWidth platform) -- Int# and Char# are rep'd the same
OrdOp -> mk_conv (platformWordWidth platform)
-- Memory primops, expand the ghci-mem-primops test if you add more.
IndexOffAddrOp_Word8 -> primOpWithRep (OP_INDEX_ADDR W8) W8
IndexOffAddrOp_Word16 -> primOpWithRep (OP_INDEX_ADDR W16) W16
IndexOffAddrOp_Word32 -> primOpWithRep (OP_INDEX_ADDR W32) W32
IndexOffAddrOp_Word64 -> only64bit $ primOpWithRep (OP_INDEX_ADDR W64) W64
_ -> Nothing
where
only64bit = if platformWordWidth platform == W64 then id else const Nothing
primArg1Width :: StgArg -> Width
primArg1Width arg
| rep <- (stgArgRepU arg)
= case rep of
AddrRep -> platformWordWidth platform
IntRep -> platformWordWidth platform
WordRep -> platformWordWidth platform
Int64Rep -> W64
Word64Rep -> W64
Int32Rep -> W32
Word32Rep -> W32
Int16Rep -> W16
Word16Rep -> W16
Int8Rep -> W8
Word8Rep -> W8
FloatRep -> unexpectedRep
DoubleRep -> unexpectedRep
BoxedRep{} -> unexpectedRep
VecRep{} -> unexpectedRep
where
unexpectedRep = panic "doPrimOp: Unexpected argument rep"
-- TODO: The slides for the result need to be two words on 32bit for 64bit ops.
mkNReturn width
| W64 <- width = RETURN L -- L works for 64 bit on any platform
| otherwise = RETURN N -- <64bit width, fits in word on all platforms
mkSlideWords width = if platformWordWidth platform < width then 2 else 1
-- Push args, execute primop, slide, return_N
-- Decides width of operation based on first argument.
sizedPrimOp op_inst = Just $ do
let width = primArg1Width (head args)
prim_code <- mkPrimOpCode init_d s p (op_inst width) $ args
let slide = mkSlideW (mkSlideWords width) (bytesToWords platform $ init_d - s) `snocOL` mkNReturn width
return $ prim_code `appOL` slide
-- primOpWithRep op w => operation @op@ resulting in result @w@ wide.
primOpWithRep :: BCInstr -> Width -> Maybe (BcM (OrdList BCInstr))
primOpWithRep op_inst result_width = Just $ do
prim_code <- mkPrimOpCode init_d s p op_inst $ args
let slide = mkSlideW (mkSlideWords result_width) (bytesToWords platform $ init_d - s) `snocOL` mkNReturn result_width
return $ prim_code `appOL` slide
-- Coerce the argument, requires them to be the same size
mk_conv :: Width -> Maybe (BcM (OrdList BCInstr))
mk_conv target_width = Just $ do
let width = primArg1Width (head args)
massert (width == target_width)
(push_code, _bytes) <- pushAtom init_d p (head args)
let slide = mkSlideW (mkSlideWords target_width) (bytesToWords platform $ init_d - s) `snocOL` mkNReturn target_width
return $ push_code `appOL` slide
-- Push the arguments on the stack and emit the given instruction
-- Pushes at least one word per non void arg.
mkPrimOpCode
:: StackDepth
-> Sequel
-> BCEnv
-> BCInstr -- The operator
-> [StgArg] -- Args, in *reverse* order (must be fully applied)
-> BcM BCInstrList
mkPrimOpCode orig_d _ p op_inst args = app_code
where
app_code = do
profile <- getProfile
let _platform = profilePlatform profile
do_pushery :: StackDepth -> [StgArg] -> BcM BCInstrList
do_pushery !d (arg : args) = do
(push,arg_bytes) <- pushAtom d p arg
more_push_code <- do_pushery (d + arg_bytes) args
return (push `appOL` more_push_code)
do_pushery !_d [] = do
return (unitOL op_inst)
-- Push on the stack in the reverse order.
do_pushery orig_d (reverse args)
-- 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
-- | Generate ByteCode for a case expression.
--
-- Note that case BCOs may be "nested" within other parent BCOs and refer to
-- its parent's variables (as in the 'BCEnv' contains variables from parent
-- frames). For more details about the interaction between case BCOs and their
-- parent frames see Note [Case continuation BCOs].
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.
ctoi_frame_header_w :: WordOff
ctoi_frame_header_w
| ubx_tuple_frame =
if profiling then 5 else 4
| otherwise = 2
-- The size of the ret_*_info frame header, whose frame returns the
-- value to the case continuation frame (ctoi_*_info)
ret_info_header_w :: WordOff
| ubx_tuple_frame = 3
| otherwise = 1
-- 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
(bndr_size, call_info, args_offsets)
| ubx_tuple_frame =
let bndr_reps = typePrimRep (idType bndr)
(call_info, args_offsets) =
layoutNativeCall profile NativeTupleReturn 0 id bndr_reps
in ( nativeCallSize call_info
, call_info
, args_offsets
)
| otherwise = ( idSizeW platform bndr
, voidTupleReturnInfo
, []
)
-- Depth of stack after the return value has been pushed
-- This is the stack depth at the continuation.
d_bndr =
d + wordsToBytes platform bndr_size
-- 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_bndr 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_bndr s p_alts rhs
return (my_discr alt, rhs_code)
| isUnboxedTupleType bndr_ty || isUnboxedSumType bndr_ty =
let bndr_ty = idPrimRepU . fromNonVoid
tuple_start = d_bndr
(call_info, args_offsets) =
layoutNativeCall profile
NativeTupleReturn
0
bndr_ty
(assertNonVoidIds bndrs)
stack_bot = d_bndr
p' = Map.insertList
[ (arg, tuple_start -
wordsToBytes platform (nativeCallSize call_info) +
offset)
| (NonVoid arg, offset) <- args_offsets]
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
(addIdReps (assertNonVoidIds real_bndrs))
size = WordOff tot_wds
stack_bot = d_bndr + 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 (idArgRep 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
-- drop the stg_ctoi_*_info header...
alt_final1 = SLIDE bndr_size ctoi_frame_header_w `consOL` alt_final0
-- after dropping the stg_ret_*_info header
alt_final2 = SLIDE 0 ret_info_header_w `consOL` alt_final1
-- When entering a case continuation BCO, the stack is always headed
-- by the stg_ret frame and the stg_ctoi frame that returned to it.
-- See Note [Stack layout when entering run_BCO]
--
-- Right after the breakpoint instruction, a case continuation BCO
-- drops the stg_ret and stg_ctoi frame headers (see alt_final1,
-- alt_final2), leaving the stack with the scrutinee followed by the
-- free variables (with depth==d_bndr)
alt_final <- getLastBreakTick >>= \case
Just (Breakpoint tick_ty tick_id fvs)
| gopt Opt_InsertBreakpoints (hsc_dflags hsc_env)
-- Construct an internal breakpoint to put at the start of this case
-- continuation BCO, for step-out.
-- See Note [Debugger: Stepout internal break locs]
-> do
-- same fvs available in the surrounding tick are available in the case continuation
-- The variable offsets into the yielded AP_STACK are adjusted
-- differently because a case continuation AP_STACK has the
-- additional stg_ret and stg_ctoi frame headers
-- (as per Note [Stack layout when entering run_BCO]):
let firstVarOff = ret_info_header_w+bndr_size+ctoi_frame_header_w
idOffSets = map (fmap (second (+firstVarOff))) $
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
(Left (InternalBreakLoc tick_id))
mibi <- newBreakInfo breakInfo
return $ case mibi of
Nothing -> alt_final2
Just ibi -> BRK_FUN ibi `consOL` alt_final2
_ -> pure alt_final2
add_bco_name <- shouldAddBcoName
let
alt_bco_name = getName bndr
alt_bco = mkProtoBCO platform add_bco_name alt_bco_name alt_final (Left alts)
0{-no arity-} bitmap_size bitmap True{-is alts-}
scrut_code <- schemeE (d + wordsToBytes platform ctoi_frame_header_w + save_ccs_size_b)
(d + wordsToBytes platform ctoi_frame_header_w + save_ccs_size_b)
p scrut
if ubx_tuple_frame
then do let tuple_bco = 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)
{-
Note [Debugger: Stepout internal break locs]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Step-out tells the interpreter to run until the current function
returns to where it was called from, and stop there.
This is achieved by enabling the BRK_FUN found on the first RET_BCO
frame on the stack (See [Note Debugger: Step-out]).
Case continuation BCOs (which select an alternative branch) must
therefore be headed by a BRK_FUN. An example:
f x = case g x of <--- end up here
1 -> ...
2 -> ...
g y = ... <--- step out from here
- `g` will return a value to the case continuation BCO in `f`
- The case continuation BCO will receive the value returned from g
- Match on it and push the alternative continuation for that branch
- And then enter that alternative.
If we step-out of `g`, the first RET_BCO on the stack is the case
continuation of `f` -- execution should stop at its start, before
selecting an alternative. (One might ask, "why not enable the breakpoint
in the alternative instead?", because the alternative continuation is
only pushed to the stack *after* it is selected by the case cont. BCO)
However, the case cont. BCO is not associated with any source-level
tick, it is merely the glue code which selects alternatives which do
have source level ticks. Therefore, we have to come up at code
generation time with a breakpoint location ('InternalBreakLoc') to
display to the user when it is stopped there.
Our solution is to use the last tick seen just before reaching the case
continuation. This is robust because a case continuation will thus
always have a relevant breakpoint location:
- The source location will be the last source-relevant expression
executed before the continuation is pushed
- So the source location will point to the thing you've just stepped
out of
- The variables available are the same as the ones bound just before entering
- Doing :step-local from there will put you on the selected
alternative (which at the source level may also be the e.g. next
line in a do-block)
Examples, using angle brackets (<<...>>) to denote the breakpoint span:
f x = case <<g x>> {- step in here -} of
1 -> ...
2 -> ...>
g y = <<...>> <--- step out from here
...
f x = <<case g x of <--- end up here, whole case highlighted
1 -> ...
2 -> ...>>
doing :step-local ...
f x = case g x of
1 -> <<...>> <--- stop in the alternative
2 -> ...
A second example based on T26042d2, where the source is a do-block IO
action, optimised to a chain of `case expressions`.
main = do
putStrLn "hello1"
<<f>> <--- step-in here
putStrLn "hello3"
putStrLn "hello4"
f = do
<<putStrLn "hello2.1">> <--- step-out from here
putStrLn "hello2.2"
...
main = do
putStrLn "hello1"
<<f>> <--- end up here again, the previously executed expression
putStrLn "hello3"
putStrLn "hello4"
doing step/step-local ...
main = do
putStrLn "hello1"
f
<<putStrLn "hello3">> <--- straight to the next line
putStrLn "hello4"
-}
-- -----------------------------------------------------------------------------
-- Deal with tuples
-- The native calling convention uses registers for tuples, but in the
-- bytecode interpreter, all values live on the stack.
{- Note [GHCi and native call registers]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The GHCi bytecode interpreter does not have access to the STG registers
that the native calling convention uses for passing arguments. It uses
helper stack frames to move values between the stack and registers.
If only a single register needs to be moved, GHCi uses a specific stack
frame. For example stg_ctoi_R1p saves a heap pointer value from STG register
R1 and stg_ctoi_D1 saves a double precision floating point value from D1.
In the other direction, helpers stg_ret_p and stg_ret_d move a value from
the stack to the R1 and D1 registers, respectively.
When GHCi needs to move more than one register it cannot use a specific
helper frame. It would simply be impossible to create a helper for all
possible combinations of register values. Instead, there are generic helper
stack frames that use a call_info word that describes the active registers
and the number of stack words used by the arguments of a call.
These helper stack frames are currently:
- stg_ret_t: return a tuple to the continuation at the top of
the stack
- stg_ctoi_t: convert a tuple return value to be used in
bytecode
- stg_primcall: call a function
The call_info word contains a bitmap of the active registers
for the call and and a stack offset. The layout is as follows:
- bit 0-23: Bitmap of active registers for the call, the
order corresponds to the list returned by
allArgRegsCover.
For example if bit 0 (the least significant bit) is set, the
first register in the allArgRegsCover
list is active. Bit 1 for the
second register in the list and so on.
- bit 24-31: Unsigned byte indicating the stack offset
of the continuation in words. For tuple returns
this is the number of words returned on the
stack. For primcalls this field is unused, since
we don't jump to a continuation.
The upper 32 bits on 64 bit platforms are currently unused.
If a register is smaller than a word on the stack (for example a
single precision float on a 64 bit system), then the stack slot
is padded to a whole word.
Example:
If a tuple is returned in three registers and an additional two
words on the stack, then three bits in the register bitmap
(bits 0-23) would be set. And bit 24-31 would be
00000010 (two in binary).
The values on the stack before a call to POP_ARG_REGS would
be as follows:
...
continuation
stack_arg_1
stack_arg_2
register_arg_3
register_arg_2
register_arg_1 <- Sp
A call to POP_ARG_REGS(call_info) would move register_arg_1
to the register corresponding to the lowest set bit in the
call_info word. register_arg_2 would be moved to the register
corresponding to the second lowest set bit, and so on.
After POP_ARG_REGS(call_info), the stack pointer Sp points
to the topmost stack argument, so the stack looks as follows:
...
continuation
stack_arg_1
stack_arg_2 <- Sp
At this point all the arguments are in place and we are ready
to jump to the continuation, the location (offset from Sp) of
which is found by inspecting the value of bits 24-31. In this
case the offset is two words.
On x86_64, the double precision (Dn) and single precision
floating (Fn) point registers overlap, e.g. D1 uses the same
physical register as F1. On this platform, the list returned
by allArgRegsCover contains only entries for the double
precision registers. If an argument is passed in register
Fn, the bit corresponding to Dn should be set.
Note: if anything changes in how registers for native calls overlap,
make sure to also update GHC.StgToByteCode.layoutNativeCall
-}
layoutNativeCall :: Profile
-> NativeCallType
-> ByteOff
-> (a -> PrimRep)
-> [a]
-> ( NativeCallInfo -- See Note [GHCi TupleInfo]
, [(a, ByteOff)] -- argument, offset on stack
)
layoutNativeCall profile call_type start_off arg_rep reps =
let platform = profilePlatform profile
arg_ty = primRepCmmType platform . arg_rep
(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 SCALAR_ARG_REGS) [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)] -> ProtoBCO Name
tupleBCO platform args_info args =
mkProtoBCO platform Nothing invented_name body_code (Left [])
0{-no arity-} bitmap_size bitmap False{-not 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)] -> ProtoBCO Name
primCallBCO platform args_info args =
mkProtoBCO platform Nothing invented_name body_code (Left [])
0{-no arity-} bitmap_size bitmap False{-not 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
stgArgRepU
nv_args
prim_args_offsets = mapFst stgArgRepU args_offsets
shifted_args_offsets = mapSnd (+ d) args_offsets
push_target = PUSH_UBX (LitLabel target 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
let args_bco = 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) `appOL` 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 _ 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, PrimOrVoidRep)]
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, NVRep AddrRep) : rest)
pargs d (aa:az) = do (code_a, sz_a) <- pushAtom d p aa
rest <- pargs (d + sz_a) az
return ((code_a, stgArgRep1 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
| VoidRep:xs <- a_reps_pushed_r_to_l
= 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.
r_rep = maybe_getCCallReturnRep result_ty
{-
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 IsFunction)
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 = case r_rep of
VoidRep -> nilOL
NVRep r -> unitOL (PUSH_UBX (mkDummyLiteral platform r) 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)
-- 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
let
-- do the call
do_call = unitOL (CCALL stk_offset (FFIInfo ffiargs ffires) 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 (toArgRepOrV 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 -> PrimOrVoidRep -> FFIType
primRepToFFIType _ VoidRep = FFIVoid
primRepToFFIType platform (NVRep r)
= case r of
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
VecRep{} -> 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
VecRep{} -> 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 NVRep 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 VoidRep
maybe_getCCallReturnRep :: Type -> PrimOrVoidRep
maybe_getCCallReturnRep fn_ty
= let
(_a_tys, r_ty) = splitFunTys (dropForAlls fn_ty)
in
case typePrimRep r_ty of
[] -> VoidRep
[rep] -> NVRep 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 (StgArg, [Name])
-- Detect and extract relevant info for the tagToEnum kludge.
maybe_is_tagToEnum_call (StgOpApp (StgPrimOp TagToEnumOp) args t)
| [v] <- args
= Just (v, extract_constr_Names t)
| otherwise
= pprPanic "StgToByteCode: tagToEnum#"
$ text "Expected exactly one arg, but actual args are:" <+> ppr args
where
extract_constr_Names ty
| rep_ty <- unwrapType ty
, Just tyc <- tyConAppTyCon_maybe rep_ty
, isBoxedDataTyCon 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
-> StgArg
-> [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 arg
labels <- getLabelsBc (strictGenericLength 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
-- See Note [LFInfo of DataCon workers and wrappers] in GHC.Types.Id.Make.
| isNullaryRepDataCon con ->
return (unitOL (PACK con 0), szb)
_
-- see Note [Generating code for top-level string literal bindings]
| idType var `eqType` addrPrimTy ->
return (unitOL (PUSH_ADDR (getName var)), szb)
| otherwise -> do
let varTy = idType var
massertPpr (definitelyLiftedType varTy) $
vcat [ text "pushAtom: unhandled unlifted type"
, text "var:" <+> ppr var <+> dcolon <+> ppr varTy <> dcolon <+> ppr (typeKind varTy)
]
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 =
-- TODO: It's a bit silly to use up to four instructions to put a single literal on the stack.
-- Lot's of better ways to do this. Add a instruction to push it as full word.
-- Store the literal as full word and push it as full word.
-- Maybe more, but for now this will do.
case platformByteOrder platform of
LittleEndian -> return (padding_instr `snocOL` instr, size_bytes + padding_bytes)
BigEndian -> return (instr `consOL` padding_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 . idArgRep 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 (idPrimRepU var))
repSizeWords :: Platform -> PrimOrVoidRep -> WordOff
repSizeWords platform rep = WordOff $ argRepSizeW platform (toArgRepOrV 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 -> False -- 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 -> OrdList BCInstr
mkSlideB platform nb db = mkSlideW 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)
atomRep :: Platform -> StgArg -> ArgRep
atomRep platform e = toArgRepOrV platform (stgArgRep1 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
-- | Read only environment for generating ByteCode
data BcM_Env
= BcM_Env
{ bcm_hsc_env :: !HscEnv
, bcm_module :: !Module -- current module (for breakpoints)
, modBreaks :: !(Maybe ModBreaks)
, last_bp_tick :: !(Maybe StgTickish)
}
data BcM_State
= BcM_State
{ nextlabel :: !Word32 -- ^ For generating local labels
, breakInfoIdx :: !Int -- ^ Next index for breakInfo array
, breakInfo :: !(IntMap CgBreakInfo)
-- ^ Info at breakpoints occurrences. Indexed with
-- 'InternalBreakpointId'. See Note [Breakpoint identifiers] in
-- GHC.ByteCode.Breakpoints.
}
newtype BcM r = BcM (BcM_Env -> BcM_State -> IO (r, BcM_State))
deriving (Functor, Applicative, Monad, MonadIO)
via (ReaderT BcM_Env (StateT BcM_State IO))
runBc :: HscEnv -> Module -> Maybe ModBreaks -> BcM r -> IO (r, BcM_State)
runBc hsc_env this_mod mbs (BcM m)
= m (BcM_Env hsc_env this_mod mbs Nothing) (BcM_State 0 0 IntMap.empty)
instance HasDynFlags BcM where
getDynFlags = hsc_dflags <$> getHscEnv
getHscEnv :: BcM HscEnv
getHscEnv = BcM $ \env st -> return (bcm_hsc_env env, st)
getProfile :: BcM Profile
getProfile = targetProfile <$> getDynFlags
shouldAddBcoName :: BcM (Maybe Module)
shouldAddBcoName = do
add <- gopt Opt_AddBcoName <$> getDynFlags
if add
then Just <$> getCurrentModule
else return Nothing
getLabelBc :: BcM LocalLabel
getLabelBc = BcM $ \_ st ->
do let nl = nextlabel st
when (nl == maxBound) $
panic "getLabelBc: Ran out of labels"
return (LocalLabel nl, st{nextlabel = nl + 1})
getLabelsBc :: Word32 -> BcM [LocalLabel]
getLabelsBc n = BcM $ \_ st ->
let ctr = nextlabel st
in return (coerce [ctr .. ctr+n-1], st{nextlabel = ctr+n})
newBreakInfo :: CgBreakInfo -> BcM (Maybe InternalBreakpointId)
newBreakInfo info = BcM $ \env st -> do
-- if we're not generating ModBreaks for this module for some reason, we
-- can't store breakpoint occurrence information.
case modBreaks env of
Nothing -> pure (Nothing, st)
Just modBreaks -> do
let ix = breakInfoIdx st
st' = st
{ breakInfo = IntMap.insert ix info (breakInfo st)
, breakInfoIdx = ix + 1
}
return (Just $ InternalBreakpointId (modBreaks_module modBreaks) ix, st')
getCurrentModule :: BcM Module
getCurrentModule = BcM $ \env st -> return (bcm_module env, st)
withBreakTick :: StgTickish -> BcM a -> BcM a
withBreakTick bp (BcM act) = BcM $ \env st ->
act env{last_bp_tick=Just bp} st
getLastBreakTick :: BcM (Maybe StgTickish)
getLastBreakTick = BcM $ \env st ->
pure (last_bp_tick env, st)
tickFS :: FastString
tickFS = fsLit "ticked"
-- Dehydrating CgBreakInfo
dehydrateCgBreakInfo :: [TyVar] -> [Maybe (Id, Word)] -> Type -> Either InternalBreakLoc BreakpointId -> CgBreakInfo
dehydrateCgBreakInfo ty_vars idOffSets tick_ty bid =
CgBreakInfo
{ cgb_tyvars = map toIfaceTvBndr ty_vars
, cgb_vars = map (fmap (\(i, offset) -> (toIfaceIdBndr i, offset))) idOffSets
, cgb_resty = toIfaceType tick_ty
, cgb_tick_id = bid
}