Safe Haskell	Safe
Language	Haskell2010

Compiler.Hoopl.Internals

Contents

Shapes
Blocks
Body
Graph
Respecting Fuel

Synopsis

Shapes

data O Source

Used at the type level to indicate an "open" structure with a unique, unnamed control-flow edge flowing in or out. Fallthrough and concatenation are permitted at an open point.

Instances

IfThenElseable O
type Fact O f = f
type IndexedCO O a b = b

data C Source

Used at the type level to indicate a "closed" structure which supports control transfer only through the use of named labels---no "fallthrough" is permitted. The number of control-flow edges is unconstrained.

Instances

IfThenElseable C
NonLocal n => LabelsPtr (n e C)
type Fact C f = FactBase f
type IndexedCO C a b = a

data MaybeO ex t where Source

Maybe type indexed by open/closed

Constructors

JustO :: t -> MaybeO O t
NothingO :: MaybeO C t

Instances

Functor (MaybeO ex)

data MaybeC ex t where Source

Maybe type indexed by closed/open

Constructors

JustC :: t -> MaybeC C t
NothingC :: MaybeC O t

Instances

Functor (MaybeC ex)

type family IndexedCO ex a b :: * Source

Either type indexed by closed/open using type families

Instances

type IndexedCO C a b = a
type IndexedCO O a b = b

data Shape ex where Source

Dynamic shape value

Constructors

Closed :: Shape C
Open :: Shape O

Blocks

data Block n e x where Source

A sequence of nodes. May be any of four shapes (OO, OC, CO, CC). Open at the entry means single entry, mutatis mutandis for exit. A closedclosed block is a basic/ block and can't be extended further. Clients should avoid manipulating blocks and should stick to either nodes or graphs.

Constructors

BlockCO :: n C O -> Block n O O -> Block n C O
BlockCC :: n C O -> Block n O O -> n O C -> Block n C C
BlockOC :: Block n O O -> n O C -> Block n O C
BNil :: Block n O O
BMiddle :: n O O -> Block n O O
BCat :: Block n O O -> Block n O O -> Block n O O
BSnoc :: Block n O O -> n O O -> Block n O O
BCons :: n O O -> Block n O O -> Block n O O

Instances

NonLocal n => NonLocal (Block n)

Predicates on Blocks

isEmptyBlock :: Block n e x -> Bool Source

Constructing blocks

emptyBlock :: Block n O O Source

blockCons :: n O O -> Block n O x -> Block n O x Source

blockSnoc :: Block n e O -> n O O -> Block n e O Source

blockJoinHead :: n C O -> Block n O x -> Block n C x Source

blockJoinTail :: Block n e O -> n O C -> Block n e C Source

blockJoin :: n C O -> Block n O O -> n O C -> Block n C C Source

blockJoinAny :: (MaybeC e (n C O), Block n O O, MaybeC x (n O C)) -> Block n e x Source

Convert a list of nodes to a block. The entry and exit node must or must not be present depending on the shape of the block.

blockAppend :: Block n e O -> Block n O x -> Block n e x Source

Deconstructing blocks

firstNode :: Block n C x -> n C O Source

lastNode :: Block n x C -> n O C Source

endNodes :: Block n C C -> (n C O, n O C) Source

blockSplitHead :: Block n C x -> (n C O, Block n O x) Source

blockSplitTail :: Block n e C -> (Block n e O, n O C) Source

blockSplit :: Block n C C -> (n C O, Block n O O, n O C) Source

Split a closed block into its entry node, open middle block, and exit node.

blockSplitAny :: Block n e x -> (MaybeC e (n C O), Block n O O, MaybeC x (n O C)) Source

Modifying blocks

replaceFirstNode :: Block n C x -> n C O -> Block n C x Source

replaceLastNode :: Block n x C -> n O C -> Block n x C Source

Converting to and from lists

blockToList :: Block n O O -> [n O O] Source

blockFromList :: [n O O] -> Block n O O Source

Maps and folds

mapBlock :: (forall e x. n e x -> n' e x) -> Block n e x -> Block n' e x Source

map a function over the nodes of a Block

mapBlock' :: (forall e x. n e x -> n' e x) -> Block n e x -> Block n' e x Source

A strict mapBlock

mapBlock3' :: forall n n' e x. (n C O -> n' C O, n O O -> n' O O, n O C -> n' O C) -> Block n e x -> Block n' e x Source

map over a block, with different functions to apply to first nodes, middle nodes and last nodes respectively. The map is strict.

foldBlockNodesF :: forall n a. (forall e x. n e x -> a -> a) -> forall e x. Block n e x -> IndexedCO e a a -> IndexedCO x a a Source

foldBlockNodesF3 :: forall n a b c. (n C O -> a -> b, n O O -> b -> b, n O C -> b -> c) -> forall e x. Block n e x -> IndexedCO e a b -> IndexedCO x c b Source

Fold a function over every node in a block, forward or backward. The fold function must be polymorphic in the shape of the nodes.

foldBlockNodesB :: forall n a. (forall e x. n e x -> a -> a) -> forall e x. Block n e x -> IndexedCO x a a -> IndexedCO e a a Source

foldBlockNodesB3 :: forall n a b c. (n C O -> b -> c, n O O -> b -> b, n O C -> a -> b) -> forall e x. Block n e x -> IndexedCO x a b -> IndexedCO e c b Source

Biasing

frontBiasBlock :: Block n e x -> Block n e x Source

A block is "front biased" if the left child of every concatenation operation is a node, not a general block; a front-biased block is analogous to an ordinary list. If a block is front-biased, then its nodes can be traversed from front to back without general recusion; tail recursion suffices. Not all shapes can be front-biased; a closed/open block is inherently back-biased.

backBiasBlock :: Block n e x -> Block n e x Source

A block is "back biased" if the right child of every concatenation operation is a node, not a general block; a back-biased block is analogous to a snoc-list. If a block is back-biased, then its nodes can be traversed from back to back without general recusion; tail recursion suffices. Not all shapes can be back-biased; an open/closed block is inherently front-biased.

Body

type Body n = LabelMap (Block n C C) Source

A (possibly empty) collection of closed/closed blocks

type Body' block n = LabelMap (block n C C) Source

Body abstracted over block

emptyBody :: Body' block n Source

bodyList :: NonLocal (block n) => Body' block n -> [(Label, block n C C)] Source

addBlock :: NonLocal thing => thing C C -> LabelMap (thing C C) -> LabelMap (thing C C) Source

bodyUnion :: forall a. LabelMap a -> LabelMap a -> LabelMap a Source

Graph

type Graph = Graph' Block Source

A control-flow graph, which may take any of four shapes (O/O, OC, CO, C/C). A graph open at the entry has a single, distinguished, anonymous entry point; if a graph is closed at the entry, its entry point(s) are supplied by a context.

data Graph' block n e x where Source

Graph' is abstracted over the block type, so that we can build graphs of annotated blocks for example (Compiler.Hoopl.Dataflow needs this).

Constructors

GNil :: Graph' block n O O
GUnit :: block n O O -> Graph' block n O O
GMany :: MaybeO e (block n O C) -> Body' block n -> MaybeO x (block n C O) -> Graph' block n e x

class NonLocal thing where Source

Gives access to the anchor points for nonlocal edges as well as the edges themselves

Methods

entryLabel Source

Arguments

:: thing C x
-> Label	The label of a first node or block

successors Source

Arguments

:: thing e C
-> [Label]	Gives control-flow successors

Instances

NonLocal n => NonLocal (Block n)

Constructing graphs

bodyGraph :: Body n -> Graph n C C Source

blockGraph :: NonLocal n => Block n e x -> Graph n e x Source

gUnitOO :: block n O O -> Graph' block n O O Source

gUnitOC :: block n O C -> Graph' block n O C Source

gUnitCO :: block n C O -> Graph' block n C O Source

gUnitCC :: NonLocal (block n) => block n C C -> Graph' block n C C Source

catGraphNodeOC :: NonLocal n => Graph n e O -> n O C -> Graph n e C Source

catGraphNodeOO :: Graph n e O -> n O O -> Graph n e O Source

catNodeCOGraph :: NonLocal n => n C O -> Graph n O x -> Graph n C x Source

catNodeOOGraph :: n O O -> Graph n O x -> Graph n O x Source

Splicing graphs

splice :: forall block n e a x. NonLocal (block n) => (forall e x. block n e O -> block n O x -> block n e x) -> Graph' block n e a -> Graph' block n a x -> Graph' block n e x Source

gSplice :: NonLocal n => Graph n e a -> Graph n a x -> Graph n e x Source

Maps

mapGraph :: (forall e x. n e x -> n' e x) -> Graph n e x -> Graph n' e x Source

Maps over all nodes in a graph.

mapGraphBlocks :: forall block n block' n' e x. (forall e x. block n e x -> block' n' e x) -> Graph' block n e x -> Graph' block' n' e x Source

Function mapGraphBlocks enables a change of representation of blocks, nodes, or both. It lifts a polymorphic block transform into a polymorphic graph transform. When the block representation stabilizes, a similar function should be provided for blocks.

Folds

foldGraphNodes :: forall n a. (forall e x. n e x -> a -> a) -> forall e x. Graph n e x -> a -> a Source

Fold a function over every node in a graph. The fold function must be polymorphic in the shape of the nodes.

Extracting Labels

labelsDefined :: forall block n e x. NonLocal (block n) => Graph' block n e x -> LabelSet Source

labelsUsed :: forall block n e x. NonLocal (block n) => Graph' block n e x -> LabelSet Source

externalEntryLabels :: forall n. NonLocal n => LabelMap (Block n C C) -> LabelSet Source

Depth-first traversals

postorder_dfs :: NonLocal (block n) => Graph' block n O x -> [block n C C] Source

Traversal: postorder_dfs returns a list of blocks reachable from the entry of enterable graph. The entry and exit are *not* included. The list has the following property:

Say a "back reference" exists if one of a block's control-flow successors precedes it in the output list

Then there are as few back references as possible

The output is suitable for use in a forward dataflow problem. For a backward problem, simply reverse the list. (postorder_dfs is sufficiently tricky to implement that one doesn't want to try and maintain both forward and backward versions.)

postorder_dfs_from :: (NonLocal block, LabelsPtr b) => LabelMap (block C C) -> b -> [block C C] Source

postorder_dfs_from_except :: forall block e. (NonLocal block, LabelsPtr e) => LabelMap (block C C) -> e -> LabelSet -> [block C C] Source

preorder_dfs :: NonLocal (block n) => Graph' block n O x -> [block n C C] Source

preorder_dfs_from_except :: forall block e. (NonLocal block, LabelsPtr e) => LabelMap (block C C) -> e -> LabelSet -> [block C C] Source

class LabelsPtr l where Source

Methods

targetLabels :: l -> [Label] Source

Instances

LabelsPtr LabelSet
LabelsPtr Label
LabelsPtr l => LabelsPtr [l]
NonLocal n => LabelsPtr (n e C)

data Label Source

Instances

Eq Label
Ord Label
Show Label
LabelsPtr Label

freshLabel :: UniqueMonad m => m Label Source

data LabelSet Source

Instances

Eq LabelSet
Ord LabelSet
Show LabelSet
IsSet LabelSet
LabelsPtr LabelSet
type ElemOf LabelSet = Label

data LabelMap v Source

Instances

IsMap LabelMap
Eq v => Eq (LabelMap v)
Ord v => Ord (LabelMap v)
Show v => Show (LabelMap v)
type KeyOf LabelMap = Label

type FactBase f = LabelMap f Source

noFacts :: FactBase f Source

lookupFact :: Label -> FactBase f -> Maybe f Source

uniqueToLbl :: Unique -> Label Source

lblToUnique :: Label -> Unique Source

data DataflowLattice a Source

A transfer function might want to use the logging flag to control debugging, as in for example, it updates just one element in a big finite map. We don't want Hoopl to show the whole fact, and only the transfer function knows exactly what changed.

Constructors

DataflowLattice
Fields fact_name :: String fact_bot :: a fact_join :: JoinFun a

type JoinFun a = Label -> OldFact a -> NewFact a -> (ChangeFlag, a) Source

newtype OldFact a Source

Constructors

OldFact a

newtype NewFact a Source

Constructors

NewFact a

type family Fact x f :: * Source

Instances

type Fact C f = FactBase f
type Fact O f = f

mkFactBase :: forall f. DataflowLattice f -> [(Label, f)] -> FactBase f Source

mkFactBase creates a FactBase from a list of (Label, fact) pairs. If the same label appears more than once, the relevant facts are joined.

data ChangeFlag Source

Constructors

NoChange
SomeChange

Instances

Eq ChangeFlag
Ord ChangeFlag

changeIf :: Bool -> ChangeFlag Source

data FwdPass m n f Source

Constructors

FwdPass
Fields fp_lattice :: DataflowLattice f fp_transfer :: FwdTransfer n f fp_rewrite :: FwdRewrite m n f

newtype FwdTransfer n f Source

Constructors

FwdTransfer3
Fields getFTransfer3 :: (n C O -> f -> f, n O O -> f -> f, n O C -> f -> FactBase f)

mkFTransfer :: (forall e x. n e x -> f -> Fact x f) -> FwdTransfer n f Source

mkFTransfer3 :: (n C O -> f -> f) -> (n O O -> f -> f) -> (n O C -> f -> FactBase f) -> FwdTransfer n f Source

newtype FwdRewrite m n f Source

Constructors

FwdRewrite3
Fields getFRewrite3 :: (n C O -> f -> m (Maybe (Graph n C O, FwdRewrite m n f)), n O O -> f -> m (Maybe (Graph n O O, FwdRewrite m n f)), n O C -> f -> m (Maybe (Graph n O C, FwdRewrite m n f)))

mkFRewrite :: FuelMonad m => (forall e x. n e x -> f -> m (Maybe (Graph n e x))) -> FwdRewrite m n f Source

Functions passed to mkFRewrite should not be aware of the fuel supply. The result returned by mkFRewrite respects fuel.

mkFRewrite3 :: forall m n f. FuelMonad m => (n C O -> f -> m (Maybe (Graph n C O))) -> (n O O -> f -> m (Maybe (Graph n O O))) -> (n O C -> f -> m (Maybe (Graph n O C))) -> FwdRewrite m n f Source

Functions passed to mkFRewrite3 should not be aware of the fuel supply. The result returned by mkFRewrite3 respects fuel.

noFwdRewrite :: Monad m => FwdRewrite m n f Source

wrapFR Source

Arguments

:: (forall e x. (n e x -> f -> m (Maybe (Graph n e x, FwdRewrite m n f))) -> n' e x -> f' -> m' (Maybe (Graph n' e x, FwdRewrite m' n' f')))	This argument may assume that any function passed to it respects fuel, and it must return a result that respects fuel.
-> FwdRewrite m n f
-> FwdRewrite m' n' f'

wrapFR2 Source

Arguments

:: (forall e x. (n1 e x -> f1 -> m1 (Maybe (Graph n1 e x, FwdRewrite m1 n1 f1))) -> (n2 e x -> f2 -> m2 (Maybe (Graph n2 e x, FwdRewrite m2 n2 f2))) -> n3 e x -> f3 -> m3 (Maybe (Graph n3 e x, FwdRewrite m3 n3 f3)))	This argument may assume that any function passed to it respects fuel, and it must return a result that respects fuel.
-> FwdRewrite m1 n1 f1
-> FwdRewrite m2 n2 f2
-> FwdRewrite m3 n3 f3

data BwdPass m n f Source

Constructors

BwdPass
Fields bp_lattice :: DataflowLattice f bp_transfer :: BwdTransfer n f bp_rewrite :: BwdRewrite m n f

newtype BwdTransfer n f Source

Constructors

BwdTransfer3
Fields getBTransfer3 :: (n C O -> f -> f, n O O -> f -> f, n O C -> FactBase f -> f)

mkBTransfer :: (forall e x. n e x -> Fact x f -> f) -> BwdTransfer n f Source

mkBTransfer3 :: (n C O -> f -> f) -> (n O O -> f -> f) -> (n O C -> FactBase f -> f) -> BwdTransfer n f Source

wrapBR Source

Arguments

:: (forall e x. Shape x -> (n e x -> Fact x f -> m (Maybe (Graph n e x, BwdRewrite m n f))) -> n' e x -> Fact x f' -> m' (Maybe (Graph n' e x, BwdRewrite m' n' f')))	This argument may assume that any function passed to it respects fuel, and it must return a result that respects fuel.
-> BwdRewrite m n f
-> BwdRewrite m' n' f'

wrapBR2 Source

Arguments

:: (forall e x. Shape x -> (n1 e x -> Fact x f1 -> m1 (Maybe (Graph n1 e x, BwdRewrite m1 n1 f1))) -> (n2 e x -> Fact x f2 -> m2 (Maybe (Graph n2 e x, BwdRewrite m2 n2 f2))) -> n3 e x -> Fact x f3 -> m3 (Maybe (Graph n3 e x, BwdRewrite m3 n3 f3)))	This argument may assume that any function passed to it respects fuel, and it must return a result that respects fuel.
-> BwdRewrite m1 n1 f1
-> BwdRewrite m2 n2 f2
-> BwdRewrite m3 n3 f3

newtype BwdRewrite m n f Source

Constructors

BwdRewrite3
Fields getBRewrite3 :: (n C O -> f -> m (Maybe (Graph n C O, BwdRewrite m n f)), n O O -> f -> m (Maybe (Graph n O O, BwdRewrite m n f)), n O C -> FactBase f -> m (Maybe (Graph n O C, BwdRewrite m n f)))

mkBRewrite :: FuelMonad m => (forall e x. n e x -> Fact x f -> m (Maybe (Graph n e x))) -> BwdRewrite m n f Source

Functions passed to mkBRewrite should not be aware of the fuel supply. The result returned by mkBRewrite respects fuel.

mkBRewrite3 :: forall m n f. FuelMonad m => (n C O -> f -> m (Maybe (Graph n C O))) -> (n O O -> f -> m (Maybe (Graph n O O))) -> (n O C -> FactBase f -> m (Maybe (Graph n O C))) -> BwdRewrite m n f Source

Functions passed to mkBRewrite3 should not be aware of the fuel supply. The result returned by mkBRewrite3 respects fuel.

noBwdRewrite :: Monad m => BwdRewrite m n f Source

analyzeAndRewriteFwd :: forall m n f e x entries. (CheckpointMonad m, NonLocal n, LabelsPtr entries) => FwdPass m n f -> MaybeC e entries -> Graph n e x -> Fact e f -> m (Graph n e x, FactBase f, MaybeO x f) Source

if the graph being analyzed is open at the entry, there must be no other entry point, or all goes horribly wrong...

analyzeAndRewriteBwd :: (CheckpointMonad m, NonLocal n, LabelsPtr entries) => BwdPass m n f -> MaybeC e entries -> Graph n e x -> Fact x f -> m (Graph n e x, FactBase f, MaybeO e f) Source

if the graph being analyzed is open at the exit, I don't quite understand the implications of possible other exits

Respecting Fuel

A value of type FwdRewrite or BwdRewrite respects fuel if any function contained within the value satisfies the following properties:

When fuel is exhausted, it always returns Nothing.
When it returns Just g rw, it consumes exactly one unit of fuel, and new rewrite rw also respects fuel.

Provided that functions passed to mkFRewrite, mkFRewrite3, mkBRewrite, and mkBRewrite3 are not aware of the fuel supply, the results respect fuel.

It is an unchecked run-time error for the argument passed to wrapFR, wrapFR2, wrapBR, or warpBR2 to return a function that does not respect fuel.