Compiler.Hoopl.Internals

Shapes

data O

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

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

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

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 :: *

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

Dynamic shape value

Constructors

Closed :: Shape C

Open :: Shape O

Blocks

data Block n e x where

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

Constructing blocks

emptyBlock :: Block n O O

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

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

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

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

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

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

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

Deconstructing blocks

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

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

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

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

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

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

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))

Modifying blocks

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

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

Converting to and from lists

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

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

Maps and folds

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

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

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

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

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

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

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

Biasing

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

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

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)

A (possibly empty) collection of closed/closed blocks

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

Body abstracted over block

emptyBody :: Body' block n

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

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

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

Graph

type Graph = Graph' Block

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

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

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

Methods

entryLabel

Arguments

:: thing C x

-> Label

The label of a first node or block

successors

Arguments

:: thing e C

-> [Label]

Gives control-flow successors

Instances

NonLocal n => NonLocal (Block n)

Constructing graphs

bodyGraph :: Body n -> Graph n C C

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

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

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

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

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

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

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

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

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

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

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

Maps

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

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

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

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

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

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

Depth-first traversals

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

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]

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

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

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

class LabelsPtr l where

Methods

targetLabels :: l -> [Label]

Instances

LabelsPtr LabelSet

LabelsPtr Label

LabelsPtr l => LabelsPtr [l]

NonLocal n => LabelsPtr (n e C)

data Label

Instances

Eq Label

Ord Label

Show Label

LabelsPtr Label

freshLabel :: UniqueMonad m => m Label

data LabelSet

Instances

Eq LabelSet

Ord LabelSet

Show LabelSet

IsSet LabelSet

LabelsPtr LabelSet

type ElemOf LabelSet = Label

data LabelMap v

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

noFacts :: FactBase f

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

uniqueToLbl :: Unique -> Label

lblToUnique :: Label -> Unique

data DataflowLattice a

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)

newtype OldFact a

Constructors

OldFact a

newtype NewFact a

Constructors

NewFact a

type family Fact x f :: *

Instances

type Fact C f = FactBase f

type Fact O f = f

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

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

Constructors

NoChange

SomeChange

Instances

Eq ChangeFlag

Ord ChangeFlag

changeIf :: Bool -> ChangeFlag

data FwdPass m n f

Constructors

FwdPass

Fields

fp_lattice :: DataflowLattice f

fp_transfer :: FwdTransfer n f

fp_rewrite :: FwdRewrite m n f

newtype FwdTransfer n f

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

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

newtype FwdRewrite m n f

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

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

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

wrapFR

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

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

Constructors

BwdPass

Fields

bp_lattice :: DataflowLattice f

bp_transfer :: BwdTransfer n f

bp_rewrite :: BwdRewrite m n f

newtype BwdTransfer n f

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

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

wrapBR

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

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

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

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

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

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)

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)

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.