GHC.Runtime.Heap.Layout

Words and bytes

type WordOff = Int

Word offset, or word count

type ByteOff = Int

Byte offset, or byte count

wordsToBytes :: Num a => Platform -> a -> a

Convert the given number of words to a number of bytes.

This function morally has type WordOff -> ByteOff, but uses Num a to allow for overloading.

bytesToWordsRoundUp :: Platform -> ByteOff -> WordOff

First round the given byte count up to a multiple of the machine's word size and then convert the result to words.

roundUpToWords :: Platform -> ByteOff -> ByteOff

Round up the given byte count to the next byte count that's a multiple of the machine's word size.

roundUpTo :: ByteOff -> ByteOff -> ByteOff

Round up base to a multiple of size.

data StgWord

Instances

Bits StgWord

Defined in GHC.Runtime.Heap.Layout

Methods

(.&.) :: StgWord -> StgWord -> StgWord

(.|.) :: StgWord -> StgWord -> StgWord

xor :: StgWord -> StgWord -> StgWord

complement :: StgWord -> StgWord

shift :: StgWord -> Int -> StgWord

rotate :: StgWord -> Int -> StgWord

zeroBits :: StgWord

bit :: Int -> StgWord

setBit :: StgWord -> Int -> StgWord

clearBit :: StgWord -> Int -> StgWord

complementBit :: StgWord -> Int -> StgWord

testBit :: StgWord -> Int -> Bool

bitSizeMaybe :: StgWord -> Maybe Int

bitSize :: StgWord -> Int

isSigned :: StgWord -> Bool

shiftL :: StgWord -> Int -> StgWord

unsafeShiftL :: StgWord -> Int -> StgWord

shiftR :: StgWord -> Int -> StgWord

unsafeShiftR :: StgWord -> Int -> StgWord

rotateL :: StgWord -> Int -> StgWord

rotateR :: StgWord -> Int -> StgWord

popCount :: StgWord -> Int

Outputable StgWord

Defined in GHC.Runtime.Heap.Layout

Methods

ppr :: StgWord -> SDoc

pprPrec :: Rational -> StgWord -> SDoc

Eq StgWord

Defined in GHC.Runtime.Heap.Layout

Methods

(==) :: StgWord -> StgWord -> Bool

(/=) :: StgWord -> StgWord -> Bool

fromStgWord :: StgWord -> Integer

toStgWord :: Platform -> Integer -> StgWord

data StgHalfWord

Instances

Outputable StgHalfWord

Defined in GHC.Runtime.Heap.Layout

Methods

ppr :: StgHalfWord -> SDoc

pprPrec :: Rational -> StgHalfWord -> SDoc

Eq StgHalfWord

Defined in GHC.Runtime.Heap.Layout

Methods

(==) :: StgHalfWord -> StgHalfWord -> Bool

(/=) :: StgHalfWord -> StgHalfWord -> Bool

fromStgHalfWord :: StgHalfWord -> Integer

toStgHalfWord :: Platform -> Integer -> StgHalfWord

halfWordSize :: Platform -> ByteOff

Half word size in bytes

halfWordSizeInBits :: Platform -> Int

Closure representation

data SMRep

A description of the layout of a closure. Corresponds directly to the closure types in includes/rts/storage/ClosureTypes.h.

Constructors

HeapRep IsStatic !WordOff !WordOff ClosureTypeInfo

ArrayPtrsRep !WordOff !WordOff

SmallArrayPtrsRep !WordOff

ArrayWordsRep !WordOff

StackRep Liveness

RTSRep Int SMRep

Instances

Outputable SMRep

Defined in GHC.Runtime.Heap.Layout

Methods

ppr :: SMRep -> SDoc

pprPrec :: Rational -> SMRep -> SDoc

type IsStatic = Bool

True <=> This is a static closure. Affects how we garbage-collect it. Static closure have an extra static link field at the end. Constructors do not have a static variant; see Note [static constructors]

data ClosureTypeInfo

Constructors

Constr ConTagZ ConstrDescription

Fun FunArity ArgDescr

Thunk

ThunkSelector SelectorOffset

BlackHole

IndStatic

Instances

Outputable ClosureTypeInfo

Defined in GHC.Runtime.Heap.Layout

Methods

ppr :: ClosureTypeInfo -> SDoc

pprPrec :: Rational -> ClosureTypeInfo -> SDoc

data ArgDescr

An ArgDescr describes the argument pattern of a function

Constructors

ArgSpec !Int

ArgGen Liveness

ArgUnknown

Instances

Outputable ArgDescr

Defined in GHC.StgToCmm.Types

Methods

ppr :: ArgDescr -> SDoc

pprPrec :: Rational -> ArgDescr -> SDoc

Eq ArgDescr

Defined in GHC.StgToCmm.Types

Methods

(==) :: ArgDescr -> ArgDescr -> Bool

(/=) :: ArgDescr -> ArgDescr -> Bool

type Liveness = [Bool]

We represent liveness bitmaps as a Bitmap (whose internal representation really is a bitmap). These are pinned onto case return vectors to indicate the state of the stack for the garbage collector.

In the compiled program, liveness bitmaps that fit inside a single word (StgWord) are stored as a single word, while larger bitmaps are stored as a pointer to an array of words.

type ConstrDescription = ByteString

Construction

mkHeapRep :: DynFlags -> IsStatic -> WordOff -> WordOff -> ClosureTypeInfo -> SMRep

blackHoleRep :: SMRep

indStaticRep :: SMRep

mkStackRep :: [Bool] -> SMRep

mkRTSRep :: Int -> SMRep -> SMRep

arrPtrsRep :: DynFlags -> WordOff -> SMRep

smallArrPtrsRep :: WordOff -> SMRep

arrWordsRep :: Platform -> ByteOff -> SMRep

Predicates

isStaticRep :: SMRep -> IsStatic

isConRep :: SMRep -> Bool

isThunkRep :: SMRep -> Bool

isFunRep :: SMRep -> Bool

isStaticNoCafCon :: SMRep -> Bool

isStackRep :: SMRep -> Bool

Size-related things

heapClosureSizeW :: DynFlags -> SMRep -> WordOff

The total size of the closure, in words.

fixedHdrSizeW :: DynFlags -> WordOff

Size of a closure header (StgHeader in includes/rts/storage/Closures.h)

arrWordsHdrSize :: DynFlags -> ByteOff

arrWordsHdrSizeW :: DynFlags -> WordOff

arrPtrsHdrSize :: DynFlags -> ByteOff

arrPtrsHdrSizeW :: DynFlags -> WordOff

profHdrSize :: DynFlags -> WordOff

Size of the profiling part of a closure header (StgProfHeader in includes/rts/storage/Closures.h)

thunkHdrSize :: DynFlags -> WordOff

nonHdrSize :: Platform -> SMRep -> ByteOff

nonHdrSizeW :: SMRep -> WordOff

smallArrPtrsHdrSize :: DynFlags -> ByteOff

smallArrPtrsHdrSizeW :: DynFlags -> WordOff

hdrSize :: DynFlags -> SMRep -> ByteOff

hdrSizeW :: DynFlags -> SMRep -> WordOff

fixedHdrSize :: DynFlags -> ByteOff

RTS closure types

rtsClosureType :: SMRep -> Int

Derives the RTS closure type from an SMRep

rET_SMALL :: Int

rET_BIG :: Int

aRG_GEN :: Int

aRG_GEN_BIG :: Int

Arrays

card :: DynFlags -> Int -> Int

The byte offset into the card table of the card for a given element

cardRoundUp :: DynFlags -> Int -> Int

Convert a number of elements to a number of cards, rounding up

cardTableSizeB :: DynFlags -> Int -> ByteOff

The size of a card table, in bytes

cardTableSizeW :: DynFlags -> Int -> WordOff

The size of a card table, in words