{- (c) The University of Glasgow 2006 (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 -} {-# LANGUAGE DeriveDataTypeable, FlexibleContexts #-} {-# LANGUAGE NamedFieldPuns #-} {-# LANGUAGE BangPatterns #-} -- | GHC.Core holds all the main data types for use by for the Glasgow Haskell Compiler midsection module GHC.Core ( -- * Main data types Expr(..), Alt(..), Bind(..), AltCon(..), Arg, CoreProgram, CoreExpr, CoreAlt, CoreBind, CoreArg, CoreBndr, TaggedExpr, TaggedAlt, TaggedBind, TaggedArg, TaggedBndr(..), deTagExpr, -- * In/Out type synonyms InId, InBind, InExpr, InAlt, InArg, InType, InKind, InBndr, InVar, InCoercion, InTyVar, InCoVar, OutId, OutBind, OutExpr, OutAlt, OutArg, OutType, OutKind, OutBndr, OutVar, OutCoercion, OutTyVar, OutCoVar, MOutCoercion, -- ** 'Expr' construction mkLet, mkLets, mkLetNonRec, mkLetRec, mkLams, mkApps, mkTyApps, mkCoApps, mkVarApps, mkTyArg, mkIntLit, mkIntLitWrap, mkWordLit, mkWordLitWrap, mkWord8Lit, mkWord64LitWord64, mkInt64LitInt64, mkCharLit, mkStringLit, mkFloatLit, mkFloatLitFloat, mkDoubleLit, mkDoubleLitDouble, mkConApp, mkConApp2, mkTyBind, mkCoBind, varToCoreExpr, varsToCoreExprs, isId, cmpAltCon, cmpAlt, ltAlt, -- ** Simple 'Expr' access functions and predicates bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts, foldBindersOfBindStrict, foldBindersOfBindsStrict, collectBinders, collectTyBinders, collectTyAndValBinders, collectNBinders, collectNValBinders_maybe, collectArgs, stripNArgs, collectArgsTicks, flattenBinds, collectFunSimple, exprToType, wrapLamBody, isValArg, isTypeArg, isCoArg, isTyCoArg, valArgCount, valBndrCount, isRuntimeArg, isRuntimeVar, -- * Unfolding data types Unfolding(..), UnfoldingCache(..), UnfoldingGuidance(..), UnfoldingSource(..), -- ** Constructing 'Unfolding's noUnfolding, bootUnfolding, evaldUnfolding, mkOtherCon, unSaturatedOk, needSaturated, boringCxtOk, boringCxtNotOk, -- ** Predicates and deconstruction on 'Unfolding' unfoldingTemplate, expandUnfolding_maybe, maybeUnfoldingTemplate, otherCons, isValueUnfolding, isEvaldUnfolding, isCheapUnfolding, isExpandableUnfolding, isConLikeUnfolding, isCompulsoryUnfolding, isStableUnfolding, isStableUserUnfolding, isStableSystemUnfolding, isInlineUnfolding, isBootUnfolding, hasCoreUnfolding, hasSomeUnfolding, canUnfold, neverUnfoldGuidance, isStableSource, -- * Annotated expression data types AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt(..), -- ** Operations on annotated expressions collectAnnArgs, collectAnnArgsTicks, -- ** Operations on annotations deAnnotate, deAnnotate', deAnnAlt, deAnnBind, collectAnnBndrs, collectNAnnBndrs, -- * Orphanhood IsOrphan(..), isOrphan, notOrphan, chooseOrphanAnchor, -- * Core rule data types CoreRule(..), RuleName, RuleFun, IdUnfoldingFun, InScopeEnv(..), RuleOpts, -- ** Operations on 'CoreRule's ruleArity, ruleName, ruleIdName, ruleActivation, setRuleIdName, ruleModule, isBuiltinRule, isLocalRule, isAutoRule, ) where import GHC.Prelude import GHC.Platform import GHC.Types.Var.Env( InScopeSet ) import GHC.Types.Var import GHC.Core.Type import GHC.Core.Coercion import GHC.Core.Rules.Config ( RuleOpts ) import GHC.Types.Name import GHC.Types.Name.Set import GHC.Types.Literal import GHC.Types.Tickish import GHC.Core.DataCon import GHC.Unit.Module import GHC.Types.Basic import GHC.Types.Unique.Set import GHC.Utils.Binary import GHC.Utils.Misc import GHC.Utils.Outputable import GHC.Utils.Panic import GHC.Utils.Panic.Plain import Data.Data hiding (TyCon) import Data.Int import Data.Word infixl 4 `mkApps`, `mkTyApps`, `mkVarApps`, `App`, `mkCoApps` -- Left associative, so that we can say (f `mkTyApps` xs `mkVarApps` ys) {- ************************************************************************ * * \subsection{The main data types} * * ************************************************************************ These data types are the heart of the compiler -} -- | This is the data type that represents GHCs core intermediate language. Currently -- GHC uses System FC <https://www.microsoft.com/en-us/research/publication/system-f-with-type-equality-coercions/> for this purpose, -- which is closely related to the simpler and better known System F <http://en.wikipedia.org/wiki/System_F>. -- -- We get from Haskell source to this Core language in a number of stages: -- -- 1. The source code is parsed into an abstract syntax tree, which is represented -- by the data type 'GHC.Hs.Expr.HsExpr' with the names being 'GHC.Types.Name.Reader.RdrNames' -- -- 2. This syntax tree is /renamed/, which attaches a 'GHC.Types.Unique.Unique' to every 'GHC.Types.Name.Reader.RdrName' -- (yielding a 'GHC.Types.Name.Name') to disambiguate identifiers which are lexically identical. -- For example, this program: -- -- @ -- f x = let f x = x + 1 -- in f (x - 2) -- @ -- -- Would be renamed by having 'Unique's attached so it looked something like this: -- -- @ -- f_1 x_2 = let f_3 x_4 = x_4 + 1 -- in f_3 (x_2 - 2) -- @ -- But see Note [Shadowing] below. -- -- 3. The resulting syntax tree undergoes type checking (which also deals with instantiating -- type class arguments) to yield a 'GHC.Hs.Expr.HsExpr' type that has 'GHC.Types.Id.Id' as it's names. -- -- 4. Finally the syntax tree is /desugared/ from the expressive 'GHC.Hs.Expr.HsExpr' type into -- this 'Expr' type, which has far fewer constructors and hence is easier to perform -- optimization, analysis and code generation on. -- -- The type parameter @b@ is for the type of binders in the expression tree. -- -- The language consists of the following elements: -- -- * Variables -- See Note [Variable occurrences in Core] -- -- * Primitive literals -- -- * Applications: note that the argument may be a 'Type'. -- See Note [Representation polymorphism invariants] -- -- * Lambda abstraction -- See Note [Representation polymorphism invariants] -- -- * Recursive and non recursive @let@s. Operationally -- this corresponds to allocating a thunk for the things -- bound and then executing the sub-expression. -- -- See Note [Core letrec invariant] -- See Note [Core let-can-float invariant] -- See Note [Representation polymorphism invariants] -- See Note [Core type and coercion invariant] -- -- * Case expression. Operationally this corresponds to evaluating -- the scrutinee (expression examined) to weak head normal form -- and then examining at most one level of resulting constructor (i.e. you -- cannot do nested pattern matching directly with this). -- -- The binder gets bound to the value of the scrutinee, -- and the 'Type' must be that of all the case alternatives -- -- IMPORTANT: see Note [Case expression invariants] -- -- * Cast an expression to a particular type. -- This is used to implement @newtype@s (a @newtype@ constructor or -- destructor just becomes a 'Cast' in Core) and GADTs. -- -- * Ticks. These are used to represent all the source annotation we -- support: profiling SCCs, HPC ticks, and GHCi breakpoints. -- -- * A type: this should only show up at the top level of an Arg -- -- * A coercion {- Note [Why does Case have a 'Type' field?] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The obvious alternative is exprType (Case scrut bndr alts) | (_,_,rhs1):_ <- alts = exprType rhs1 But caching the type in the Case constructor exprType (Case scrut bndr ty alts) = ty is better for at least three reasons: * It works when there are no alternatives (see case invariant 1 above) * It might be faster in deeply-nested situations. * It might not be quite the same as (exprType rhs) for one of the RHSs in alts. Consider a phantom type synonym type S a = Int and we want to form the case expression case x of { K (a::*) -> (e :: S a) } Then exprType of the RHS is (S a), but we cannot make that be the 'ty' in the Case constructor because 'a' is simply not in scope there. Instead we must expand the synonym to Int before putting it in the Case constructor. See GHC.Core.Utils.mkSingleAltCase. So we'd have to do synonym expansion in exprType which would be inefficient. * The type stored in the case is checked with lintInTy. This checks (among other things) that it does not mention any variables that are not in scope. If we did not have the type there, it would be a bit harder for Core Lint to reject case blah of Ex x -> x where data Ex = forall a. Ex a. -} -- If you edit this type, you may need to update the GHC formalism -- See Note [GHC Formalism] in GHC.Core.Lint data Expr b = Var Id | Lit Literal | App (Expr b) (Arg b) | Lam b (Expr b) | Let (Bind b) (Expr b) | Case (Expr b) b Type [Alt b] -- See Note [Case expression invariants] -- and Note [Why does Case have a 'Type' field?] | Cast (Expr b) CoercionR -- The Coercion has Representational role | Tick CoreTickish (Expr b) | Type Type | Coercion Coercion deriving Typeable (Expr b) Typeable (Expr b) => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Expr b -> c (Expr b)) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Expr b)) -> (Expr b -> Constr) -> (Expr b -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Expr b))) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Expr b))) -> ((forall b. Data b => b -> b) -> Expr b -> Expr b) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r) -> (forall u. (forall d. Data d => d -> u) -> Expr b -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> Expr b -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b)) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b)) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b)) -> Data (Expr b) Expr b -> Constr Expr b -> DataType (forall b. Data b => b -> b) -> Expr b -> Expr b forall b. Data b => Typeable (Expr b) forall b. Data b => Expr b -> Constr forall b. Data b => Expr b -> DataType forall b. Data b => (forall b. Data b => b -> b) -> Expr b -> Expr b forall b u. Data b => Arity -> (forall d. Data d => d -> u) -> Expr b -> u forall b u. Data b => (forall d. Data d => d -> u) -> Expr b -> [u] forall b r r'. Data b => (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r forall b r r'. Data b => (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r forall b (m :: * -> *). (Data b, Monad m) => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) forall b (c :: * -> *). Data b => (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Expr b) forall b (c :: * -> *). Data b => (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Expr b -> c (Expr b) forall b (t :: * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d. Data d => c (t d)) -> Maybe (c (Expr b)) forall b (t :: * -> * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Expr b)) forall a. Typeable a => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> a -> c a) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c a) -> (a -> Constr) -> (a -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c a)) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a)) -> ((forall b. Data b => b -> b) -> a -> a) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall u. (forall d. Data d => d -> u) -> a -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> a -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> Data a forall u. Arity -> (forall d. Data d => d -> u) -> Expr b -> u forall u. (forall d. Data d => d -> u) -> Expr b -> [u] forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Expr b) forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Expr b -> c (Expr b) forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Expr b)) forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Expr b)) $cgfoldl :: forall b (c :: * -> *). Data b => (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Expr b -> c (Expr b) gfoldl :: forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Expr b -> c (Expr b) $cgunfold :: forall b (c :: * -> *). Data b => (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Expr b) gunfold :: forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Expr b) $ctoConstr :: forall b. Data b => Expr b -> Constr toConstr :: Expr b -> Constr $cdataTypeOf :: forall b. Data b => Expr b -> DataType dataTypeOf :: Expr b -> DataType $cdataCast1 :: forall b (t :: * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d. Data d => c (t d)) -> Maybe (c (Expr b)) dataCast1 :: forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Expr b)) $cdataCast2 :: forall b (t :: * -> * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Expr b)) dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Expr b)) $cgmapT :: forall b. Data b => (forall b. Data b => b -> b) -> Expr b -> Expr b gmapT :: (forall b. Data b => b -> b) -> Expr b -> Expr b $cgmapQl :: forall b r r'. Data b => (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r gmapQl :: forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r $cgmapQr :: forall b r r'. Data b => (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Expr b -> r $cgmapQ :: forall b u. Data b => (forall d. Data d => d -> u) -> Expr b -> [u] gmapQ :: forall u. (forall d. Data d => d -> u) -> Expr b -> [u] $cgmapQi :: forall b u. Data b => Arity -> (forall d. Data d => d -> u) -> Expr b -> u gmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> Expr b -> u $cgmapM :: forall b (m :: * -> *). (Data b, Monad m) => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) gmapM :: forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) $cgmapMp :: forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) gmapMp :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) $cgmapMo :: forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) gmapMo :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Expr b -> m (Expr b) Data -- | Type synonym for expressions that occur in function argument positions. -- Only 'Arg' should contain a 'Type' at top level, general 'Expr' should not type Arg b = Expr b -- | A case split alternative. Consists of the constructor leading to the alternative, -- the variables bound from the constructor, and the expression to be executed given that binding. -- The default alternative is @(DEFAULT, [], rhs)@ -- If you edit this type, you may need to update the GHC formalism -- See Note [GHC Formalism] in GHC.Core.Lint data Alt b = Alt AltCon [b] (Expr b) deriving (Typeable (Alt b) Typeable (Alt b) => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Alt b -> c (Alt b)) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Alt b)) -> (Alt b -> Constr) -> (Alt b -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Alt b))) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Alt b))) -> ((forall b. Data b => b -> b) -> Alt b -> Alt b) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r) -> (forall u. (forall d. Data d => d -> u) -> Alt b -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> Alt b -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b)) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b)) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b)) -> Data (Alt b) Alt b -> Constr Alt b -> DataType (forall b. Data b => b -> b) -> Alt b -> Alt b forall b. Data b => Typeable (Alt b) forall b. Data b => Alt b -> Constr forall b. Data b => Alt b -> DataType forall b. Data b => (forall b. Data b => b -> b) -> Alt b -> Alt b forall b u. Data b => Arity -> (forall d. Data d => d -> u) -> Alt b -> u forall b u. Data b => (forall d. Data d => d -> u) -> Alt b -> [u] forall b r r'. Data b => (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r forall b r r'. Data b => (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r forall b (m :: * -> *). (Data b, Monad m) => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) forall b (c :: * -> *). Data b => (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Alt b) forall b (c :: * -> *). Data b => (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Alt b -> c (Alt b) forall b (t :: * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d. Data d => c (t d)) -> Maybe (c (Alt b)) forall b (t :: * -> * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Alt b)) forall a. Typeable a => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> a -> c a) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c a) -> (a -> Constr) -> (a -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c a)) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a)) -> ((forall b. Data b => b -> b) -> a -> a) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall u. (forall d. Data d => d -> u) -> a -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> a -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> Data a forall u. Arity -> (forall d. Data d => d -> u) -> Alt b -> u forall u. (forall d. Data d => d -> u) -> Alt b -> [u] forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Alt b) forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Alt b -> c (Alt b) forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Alt b)) forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Alt b)) $cgfoldl :: forall b (c :: * -> *). Data b => (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Alt b -> c (Alt b) gfoldl :: forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Alt b -> c (Alt b) $cgunfold :: forall b (c :: * -> *). Data b => (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Alt b) gunfold :: forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Alt b) $ctoConstr :: forall b. Data b => Alt b -> Constr toConstr :: Alt b -> Constr $cdataTypeOf :: forall b. Data b => Alt b -> DataType dataTypeOf :: Alt b -> DataType $cdataCast1 :: forall b (t :: * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d. Data d => c (t d)) -> Maybe (c (Alt b)) dataCast1 :: forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Alt b)) $cdataCast2 :: forall b (t :: * -> * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Alt b)) dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Alt b)) $cgmapT :: forall b. Data b => (forall b. Data b => b -> b) -> Alt b -> Alt b gmapT :: (forall b. Data b => b -> b) -> Alt b -> Alt b $cgmapQl :: forall b r r'. Data b => (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r gmapQl :: forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r $cgmapQr :: forall b r r'. Data b => (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Alt b -> r $cgmapQ :: forall b u. Data b => (forall d. Data d => d -> u) -> Alt b -> [u] gmapQ :: forall u. (forall d. Data d => d -> u) -> Alt b -> [u] $cgmapQi :: forall b u. Data b => Arity -> (forall d. Data d => d -> u) -> Alt b -> u gmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> Alt b -> u $cgmapM :: forall b (m :: * -> *). (Data b, Monad m) => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) gmapM :: forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) $cgmapMp :: forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) gmapMp :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) $cgmapMo :: forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) gmapMo :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Alt b -> m (Alt b) Data) -- | A case alternative constructor (i.e. pattern match) -- If you edit this type, you may need to update the GHC formalism -- See Note [GHC Formalism] in GHC.Core.Lint data AltCon = DataAlt DataCon -- ^ A plain data constructor: @case e of { Foo x -> ... }@. -- Invariant: the 'DataCon' is always from a @data@ type, and never from a @newtype@ | LitAlt Literal -- ^ A literal: @case e of { 1 -> ... }@ -- Invariant: always an *unlifted* literal -- See Note [Literal alternatives] | DEFAULT -- ^ Trivial alternative: @case e of { _ -> ... }@ deriving (AltCon -> AltCon -> Bool (AltCon -> AltCon -> Bool) -> (AltCon -> AltCon -> Bool) -> Eq AltCon forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a $c== :: AltCon -> AltCon -> Bool == :: AltCon -> AltCon -> Bool $c/= :: AltCon -> AltCon -> Bool /= :: AltCon -> AltCon -> Bool Eq, Typeable AltCon Typeable AltCon => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> AltCon -> c AltCon) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c AltCon) -> (AltCon -> Constr) -> (AltCon -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c AltCon)) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c AltCon)) -> ((forall b. Data b => b -> b) -> AltCon -> AltCon) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r) -> (forall u. (forall d. Data d => d -> u) -> AltCon -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> AltCon -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon) -> Data AltCon AltCon -> Constr AltCon -> DataType (forall b. Data b => b -> b) -> AltCon -> AltCon forall a. Typeable a => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> a -> c a) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c a) -> (a -> Constr) -> (a -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c a)) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a)) -> ((forall b. Data b => b -> b) -> a -> a) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall u. (forall d. Data d => d -> u) -> a -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> a -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> Data a forall u. Arity -> (forall d. Data d => d -> u) -> AltCon -> u forall u. (forall d. Data d => d -> u) -> AltCon -> [u] forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c AltCon forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> AltCon -> c AltCon forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c AltCon) forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c AltCon) $cgfoldl :: forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> AltCon -> c AltCon gfoldl :: forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> AltCon -> c AltCon $cgunfold :: forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c AltCon gunfold :: forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c AltCon $ctoConstr :: AltCon -> Constr toConstr :: AltCon -> Constr $cdataTypeOf :: AltCon -> DataType dataTypeOf :: AltCon -> DataType $cdataCast1 :: forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c AltCon) dataCast1 :: forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c AltCon) $cdataCast2 :: forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c AltCon) dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c AltCon) $cgmapT :: (forall b. Data b => b -> b) -> AltCon -> AltCon gmapT :: (forall b. Data b => b -> b) -> AltCon -> AltCon $cgmapQl :: forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r gmapQl :: forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r $cgmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> AltCon -> r $cgmapQ :: forall u. (forall d. Data d => d -> u) -> AltCon -> [u] gmapQ :: forall u. (forall d. Data d => d -> u) -> AltCon -> [u] $cgmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> AltCon -> u gmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> AltCon -> u $cgmapM :: forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon gmapM :: forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon $cgmapMp :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon gmapMp :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon $cgmapMo :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon gmapMo :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> AltCon -> m AltCon Data) -- This instance is a bit shady. It can only be used to compare AltCons for -- a single type constructor. Fortunately, it seems quite unlikely that we'll -- ever need to compare AltCons for different type constructors. -- The instance adheres to the order described in [Core case invariants] instance Ord AltCon where compare :: AltCon -> AltCon -> Ordering compare (DataAlt DataCon con1) (DataAlt DataCon con2) = Bool -> Ordering -> Ordering forall a. HasCallStack => Bool -> a -> a assert (DataCon -> TyCon dataConTyCon DataCon con1 TyCon -> TyCon -> Bool forall a. Eq a => a -> a -> Bool == DataCon -> TyCon dataConTyCon DataCon con2) (Ordering -> Ordering) -> Ordering -> Ordering forall a b. (a -> b) -> a -> b $ Arity -> Arity -> Ordering forall a. Ord a => a -> a -> Ordering compare (DataCon -> Arity dataConTag DataCon con1) (DataCon -> Arity dataConTag DataCon con2) compare (DataAlt DataCon _) AltCon _ = Ordering GT compare AltCon _ (DataAlt DataCon _) = Ordering LT compare (LitAlt Literal l1) (LitAlt Literal l2) = Literal -> Literal -> Ordering forall a. Ord a => a -> a -> Ordering compare Literal l1 Literal l2 compare (LitAlt Literal _) AltCon DEFAULT = Ordering GT compare AltCon DEFAULT AltCon DEFAULT = Ordering EQ compare AltCon DEFAULT AltCon _ = Ordering LT -- | Binding, used for top level bindings in a module and local bindings in a @let@. -- If you edit this type, you may need to update the GHC formalism -- See Note [GHC Formalism] in GHC.Core.Lint data Bind b = NonRec b (Expr b) | Rec [(b, (Expr b))] deriving Typeable (Bind b) Typeable (Bind b) => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Bind b -> c (Bind b)) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Bind b)) -> (Bind b -> Constr) -> (Bind b -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Bind b))) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Bind b))) -> ((forall b. Data b => b -> b) -> Bind b -> Bind b) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r) -> (forall u. (forall d. Data d => d -> u) -> Bind b -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> Bind b -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b)) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b)) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b)) -> Data (Bind b) Bind b -> Constr Bind b -> DataType (forall b. Data b => b -> b) -> Bind b -> Bind b forall b. Data b => Typeable (Bind b) forall b. Data b => Bind b -> Constr forall b. Data b => Bind b -> DataType forall b. Data b => (forall b. Data b => b -> b) -> Bind b -> Bind b forall b u. Data b => Arity -> (forall d. Data d => d -> u) -> Bind b -> u forall b u. Data b => (forall d. Data d => d -> u) -> Bind b -> [u] forall b r r'. Data b => (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r forall b r r'. Data b => (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r forall b (m :: * -> *). (Data b, Monad m) => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) forall b (c :: * -> *). Data b => (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Bind b) forall b (c :: * -> *). Data b => (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Bind b -> c (Bind b) forall b (t :: * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d. Data d => c (t d)) -> Maybe (c (Bind b)) forall b (t :: * -> * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Bind b)) forall a. Typeable a => (forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> a -> c a) -> (forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c a) -> (a -> Constr) -> (a -> DataType) -> (forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c a)) -> (forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a)) -> ((forall b. Data b => b -> b) -> a -> a) -> (forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r) -> (forall u. (forall d. Data d => d -> u) -> a -> [u]) -> (forall u. Arity -> (forall d. Data d => d -> u) -> a -> u) -> (forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> (forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> a -> m a) -> Data a forall u. Arity -> (forall d. Data d => d -> u) -> Bind b -> u forall u. (forall d. Data d => d -> u) -> Bind b -> [u] forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Bind b) forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Bind b -> c (Bind b) forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Bind b)) forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Bind b)) $cgfoldl :: forall b (c :: * -> *). Data b => (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Bind b -> c (Bind b) gfoldl :: forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Bind b -> c (Bind b) $cgunfold :: forall b (c :: * -> *). Data b => (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Bind b) gunfold :: forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Bind b) $ctoConstr :: forall b. Data b => Bind b -> Constr toConstr :: Bind b -> Constr $cdataTypeOf :: forall b. Data b => Bind b -> DataType dataTypeOf :: Bind b -> DataType $cdataCast1 :: forall b (t :: * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d. Data d => c (t d)) -> Maybe (c (Bind b)) dataCast1 :: forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Bind b)) $cdataCast2 :: forall b (t :: * -> * -> *) (c :: * -> *). (Data b, Typeable t) => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Bind b)) dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Bind b)) $cgmapT :: forall b. Data b => (forall b. Data b => b -> b) -> Bind b -> Bind b gmapT :: (forall b. Data b => b -> b) -> Bind b -> Bind b $cgmapQl :: forall b r r'. Data b => (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r gmapQl :: forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r $cgmapQr :: forall b r r'. Data b => (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Bind b -> r $cgmapQ :: forall b u. Data b => (forall d. Data d => d -> u) -> Bind b -> [u] gmapQ :: forall u. (forall d. Data d => d -> u) -> Bind b -> [u] $cgmapQi :: forall b u. Data b => Arity -> (forall d. Data d => d -> u) -> Bind b -> u gmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> Bind b -> u $cgmapM :: forall b (m :: * -> *). (Data b, Monad m) => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) gmapM :: forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) $cgmapMp :: forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) gmapMp :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) $cgmapMo :: forall b (m :: * -> *). (Data b, MonadPlus m) => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) gmapMo :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> Bind b -> m (Bind b) Data {- Note [Shadowing] ~~~~~~~~~~~~~~~~ While various passes attempt to rename on-the-fly in a manner that avoids "shadowing" (thereby simplifying downstream optimizations), neither the simplifier nor any other pass GUARANTEES that shadowing is avoided. Thus, all passes SHOULD work fine even in the presence of arbitrary shadowing in their inputs. In particular, scrutinee variables `x` in expressions of the form `Case e x t` are often renamed to variables with a prefix "wild_". These "wild" variables may appear in the body of the case-expression, and further, may be shadowed within the body. So the Unique in a Var is not really unique at all. Still, it's very useful to give a constant-time equality/ordering for Vars, and to give a key that can be used to make sets of Vars (VarSet), or mappings from Vars to other things (VarEnv). Moreover, if you do want to eliminate shadowing, you can give a new Unique to an Id without changing its printable name, which makes debugging easier. Note [Literal alternatives] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Literal alternatives (LitAlt lit) are always for *un-lifted* literals. We have one literal, a literal Integer, that is lifted, and we don't allow in a LitAlt, because LitAlt cases don't do any evaluation. Also (see #5603) if you say case 3 of IS x -> ... IP _ -> ... IN _ -> ... (where IS, IP, IN are the constructors for Integer) we don't want the simplifier calling findAlt with argument (LitAlt 3). No no. Integer literals are an opaque encoding of an algebraic data type, not of an unlifted literal, like all the others. Also, we do not permit case analysis with literal patterns on floating-point types. See #9238 and Note [Rules for floating-point comparisons] in GHC.Core.Opt.ConstantFold for the rationale for this restriction. -------------------------- GHC.Core INVARIANTS --------------------------- Note [Variable occurrences in Core] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Variable /occurrences/ are never CoVars, though /bindings/ can be. All CoVars appear in Coercions. For example \(c :: Age~#Int) (d::Int). d |> (sym c) Here 'c' is a CoVar, which is lambda-bound, but it /occurs/ in a Coercion, (sym c). Note [Core letrec invariant] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The Core letrec invariant: The right hand sides of all /top-level/ or /recursive/ bindings must be of lifted type There is one exception to this rule, top-level @let@s are allowed to bind primitive string literals: see Note [Core top-level string literals]. See "Type#type_classification" in GHC.Core.Type for the meaning of "lifted" vs. "unlifted"). For the non-top-level, non-recursive case see Note [Core let-can-float invariant]. Note [Compilation plan for top-level string literals] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is a summary on how top-level string literals are handled by various parts of the compilation pipeline. * In the source language, there is no way to bind a primitive string literal at the top level. * In Core, we have a special rule that permits top-level Addr# bindings. See Note [Core top-level string literals]. Core-to-core passes may introduce new top-level string literals. * In STG, top-level string literals are explicitly represented in the syntax tree. * A top-level string literal may end up exported from a module. In this case, in the object file, the content of the exported literal is given a label with the _bytes suffix. Note [Core let-can-float invariant] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The let-can-float invariant: The right hand side of a /non-top-level/, /non-recursive/ binding may be of unlifted type, but only if the expression is ok-for-speculation or the 'Let' is for a join point. (For top-level or recursive lets see Note [Core letrec invariant].) This means that the let can be floated around without difficulty. For example, this is OK: y::Int# = x +# 1# But this is not, as it may affect termination if the expression is floated out: y::Int# = fac 4# In this situation you should use @case@ rather than a @let@. The function 'GHC.Core.Utils.needsCaseBinding' can help you determine which to generate, or alternatively use 'GHC.Core.Make.mkCoreLet' rather than this constructor directly, which will generate a @case@ if necessary The let-can-float invariant is initially enforced by mkCoreLet in GHC.Core.Make. For discussion of some implications of the let-can-float invariant primops see Note [Checking versus non-checking primops] in GHC.Builtin.PrimOps. Historical Note [The let/app invariant] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Before 2022 GHC used the "let/app invariant", which applied the let-can-float rules to the argument of an application, as well as to the RHS of a let. This made some kind of sense, because 'let' can always be encoded as application: let x=rhs in b = (\x.b) rhs But the let/app invariant got in the way of RULES; see #19313. For example up :: Int# -> Int# {-# RULES "up/down" forall x. up (down x) = x #-} The LHS of this rule doesn't satisfy the let/app invariant. Indeed RULES is a big reason that GHC doesn't use ANF, where the argument of an application is always a variable or a constant. To allow RULES to work nicely we need to allow lots of things in the arguments of a call. TL;DR: we relaxed the let/app invariant to become the let-can-float invariant. Note [Core top-level string literals] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ As an exception to the usual rule that top-level binders must be lifted, we allow binding primitive string literals (of type Addr#) of type Addr# at the top level. This allows us to share string literals earlier in the pipeline and crucially allows other optimizations in the Core2Core pipeline to fire. Consider, f n = let a::Addr# = "foo"# in \x -> blah In order to be able to inline `f`, we would like to float `a` to the top. Another option would be to inline `a`, but that would lead to duplicating string literals, which we want to avoid. See #8472. The solution is simply to allow top-level unlifted binders. We can't allow arbitrary unlifted expression at the top-level though, unlifted binders cannot be thunks, so we just allow string literals. We allow the top-level primitive string literals to be wrapped in Ticks in the same way they can be wrapped when nested in an expression. CoreToSTG currently discards Ticks around top-level primitive string literals. See #14779. Also see Note [Compilation plan for top-level string literals]. Note [Compilation plan for top-level string literals] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is a summary on how top-level string literals are handled by various parts of the compilation pipeline. * In the source language, there is no way to bind a primitive string literal at the top level. * In Core, we have a special rule that permits top-level Addr# bindings. See Note [Core top-level string literals]. Core-to-core passes may introduce new top-level string literals. See GHC.Core.Utils.exprIsTopLevelBindable, and exprIsTickedString * In STG, top-level string literals are explicitly represented in the syntax tree. * A top-level string literal may end up exported from a module. In this case, in the object file, the content of the exported literal is given a label with the _bytes suffix. Note [Case expression invariants] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Case expressions are one of the more complicated elements of the Core language, and come with a number of invariants. All of them should be checked by Core Lint. 1. The list of alternatives may be empty; See Note [Empty case alternatives] 2. The 'DEFAULT' case alternative must be first in the list, if it occurs at all. Checked in GHC.Core.Lint.checkCaseAlts. 3. The remaining cases are in order of (strictly) increasing tag (for 'DataAlts') or lit (for 'LitAlts'). This makes finding the relevant constructor easy, and makes comparison easier too. Checked in GHC.Core.Lint.checkCaseAlts. 4. The list of alternatives must be exhaustive. An /exhaustive/ case does not necessarily mention all constructors: @ data Foo = Red | Green | Blue ... case x of Red -> True other -> f (case x of Green -> ... Blue -> ... ) ... @ The inner case does not need a @Red@ alternative, because @x@ can't be @Red@ at that program point. This is not checked by Core Lint -- it's very hard to do so. E.g. suppose that inner case was floated out, thus: let a = case x of Green -> ... Blue -> ... ) case x of Red -> True other -> f a Now it's really hard to see that the Green/Blue case is exhaustive. But it is. If you have a case-expression that really /isn't/ exhaustive, we may generate seg-faults. Consider the Green/Blue case above. Since there are only two branches we may generate code that tests for Green, and if not Green simply /assumes/ Blue (since, if the case is exhaustive, that's all that remains). Of course, if it's not Blue and we start fetching fields that should be in a Blue constructor, we may die horribly. See also Note [Core Lint guarantee] in GHC.Core.Lint. 5. Floating-point values must not be scrutinised against literals. See #9238 and Note [Rules for floating-point comparisons] in GHC.Core.Opt.ConstantFold for rationale. Checked in lintCaseExpr; see the call to isFloatingPrimTy. 6. The 'ty' field of (Case scrut bndr ty alts) is the type of the /entire/ case expression. Checked in lintAltExpr. See also Note [Why does Case have a 'Type' field?]. 7. The type of the scrutinee must be the same as the type of the case binder, obviously. Checked in lintCaseExpr. 8. The multiplicity of the binders in constructor patterns must be the multiplicity of the corresponding field /scaled by the multiplicity of the case binder/. Checked in lintCoreAlt. Note [Core type and coercion invariant] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We allow a /non-recursive/, /non-top-level/ let to bind type and coercion variables. These can be very convenient for postponing type substitutions until the next run of the simplifier. * A type variable binding must have a RHS of (Type ty) * A coercion variable binding must have a RHS of (Coercion co) It is possible to have terms that return a coercion, but we use case-binding for those; e.g. case (eq_sel d) of (co :: a ~# b) -> blah where eq_sel :: (a~b) -> (a~#b) Or even case (df @Int) of (co :: a ~# b) -> blah Which is very exotic, and I think never encountered; but see Note [Equality superclasses in quantified constraints] in GHC.Tc.Solver.Canonical Note [Core case invariants] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ See Note [Case expression invariants] Note [Representation polymorphism invariants] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GHC allows us to abstract over calling conventions using **representation polymorphism**. For example, we have: ($) :: forall (r :: RuntimeRep) (a :: Type) (b :: TYPE r). a -> b -> b In this example, the type `b` is representation-polymorphic: it has kind `TYPE r`, where the type variable `r :: RuntimeRep` abstracts over the runtime representation of values of type `b`. To ensure that programs containing representation-polymorphism remain compilable, we enforce the following representation-polymorphism invariants: The paper "Levity Polymorphism" [PLDI'17] states the first two invariants: I1. The type of a bound variable must have a fixed runtime representation (except for join points: See Note [Invariants on join points]) I2. The type of a function argument must have a fixed runtime representation. On top of these two invariants, GHC's internal eta-expansion mechanism also requires: I3. In any partial application `f e_1 .. e_n`, where `f` is `hasNoBinding`, it must be the case that the application can be eta-expanded to match the arity of `f`. See Note [checkCanEtaExpand] in GHC.Core.Lint for more details. Example of I1: \(r::RuntimeRep). \(a::TYPE r). \(x::a). e This contravenes I1 because x's type has kind (TYPE r), which has 'r' free. We thus wouldn't know how to compile this lambda abstraction. Example of I2: f (undefined :: (a :: TYPE r)) This contravenes I2: we are applying the function `f` to a value with an unknown runtime representation. Examples of I3: myUnsafeCoerce# :: forall {r1} (a :: TYPE r1) {r2} (b :: TYPE r2). a -> b myUnsafeCoerce# = unsafeCoerce# This contravenes I3: we are instantiating `unsafeCoerce#` without any value arguments, and with a remaining argument type, `a`, which does not have a fixed runtime representation. But `unsafeCorce#` has no binding (see Note [Wiring in unsafeCoerce#] in GHC.HsToCore). So before code-generation we must saturate it by eta-expansion (see GHC.CoreToStg.Prep.maybeSaturate), thus myUnsafeCoerce# = \x. unsafeCoerce# x But we can't do that because now the \x binding would violate I1. bar :: forall (a :: TYPE) r (b :: TYPE r). a -> b bar = unsafeCoerce# OK: eta expand to `\ (x :: Type) -> unsafeCoerce# x`, and `x` has a fixed RuntimeRep. Note that we currently require something slightly stronger than a fixed runtime representation: we check whether bound variables and function arguments have a /fixed RuntimeRep/ in the sense of Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete. See Note [Representation polymorphism checking] in GHC.Tc.Utils.Concrete for an overview of how we enforce these invariants in the typechecker. Note [Core let goal] ~~~~~~~~~~~~~~~~~~~~ * The simplifier tries to ensure that if the RHS of a let is a constructor application, its arguments are trivial, so that the constructor can be inlined vigorously. Note [Empty case alternatives] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The alternatives of a case expression should be exhaustive. But this exhaustive list can be empty! * A case expression can have empty alternatives if (and only if) the scrutinee is bound to raise an exception or diverge. When do we know this? See Note [Bottoming expressions] in GHC.Core.Utils. * The possibility of empty alternatives is one reason we need a type on the case expression: if the alternatives are empty we can't get the type from the alternatives! * In the case of empty types (see Note [Bottoming expressions]), say data T we do NOT want to replace case (x::T) of Bool {} --> error Bool "Inaccessible case" because x might raise an exception, and *that*'s what we want to see! (#6067 is an example.) To preserve semantics we'd have to say x `seq` error Bool "Inaccessible case" but the 'seq' is just such a case, so we are back to square 1. * We can use the empty-alternative construct to coerce error values from one type to another. For example f :: Int -> Int f n = error "urk" g :: Int -> (# Char, Bool #) g x = case f x of { 0 -> ..., n -> ... } Then if we inline f in g's RHS we get case (error Int "urk") of (# Char, Bool #) { ... } and we can discard the alternatives since the scrutinee is bottom to give case (error Int "urk") of (# Char, Bool #) {} This is nicer than using an unsafe coerce between Int ~ (# Char,Bool #), if for no other reason that we don't need to instantiate the (~) at an unboxed type. * We treat a case expression with empty alternatives as trivial iff its scrutinee is (see GHC.Core.Utils.exprIsTrivial). This is actually important; see Note [Empty case is trivial] in GHC.Core.Utils * An empty case is replaced by its scrutinee during the CoreToStg conversion; remember STG is un-typed, so there is no need for the empty case to do the type conversion. Note [Join points] ~~~~~~~~~~~~~~~~~~ In Core, a *join point* is a specially tagged function whose only occurrences are saturated tail calls. A tail call can appear in these places: 1. In the branches (not the scrutinee) of a case 2. Underneath a let (value or join point) 3. Inside another join point We write a join-point declaration as join j @a @b x y = e1 in e2, like a let binding but with "join" instead (or "join rec" for "let rec"). Note that we put the parameters before the = rather than using lambdas; this is because it's relevant how many parameters the join point takes *as a join point.* This number is called the *join arity,* distinct from arity because it counts types as well as values. Note that a join point may return a lambda! So join j x = x + 1 is different from join j = \x -> x + 1 The former has join arity 1, while the latter has join arity 0. The identifier for a join point is called a join id or a *label.* An invocation is called a *jump.* We write a jump using the jump keyword: jump j 3 The words *label* and *jump* are evocative of assembly code (or Cmm) for a reason: join points are indeed compiled as labeled blocks, and jumps become actual jumps (plus argument passing and stack adjustment). There is no closure allocated and only a fraction of the function-call overhead. Hence we would like as many functions as possible to become join points (see OccurAnal) and the type rules for join points ensure we preserve the properties that make them efficient. In the actual AST, a join point is indicated by the IdDetails of the binder: a local value binding gets 'VanillaId' but a join point gets a 'JoinId' with its join arity. For more details, see the paper: Luke Maurer, Paul Downen, Zena Ariola, and Simon Peyton Jones. "Compiling without continuations." Submitted to PLDI'17. https://www.microsoft.com/en-us/research/publication/compiling-without-continuations/ Note [Invariants on join points] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Join points must follow these invariants: 1. All occurrences must be tail calls. Each of these tail calls must pass the same number of arguments, counting both types and values; we call this the "join arity" (to distinguish from regular arity, which only counts values). See Note [Join points are less general than the paper] 2. For join arity n, the right-hand side must begin with at least n lambdas. No ticks, no casts, just lambdas! C.f. GHC.Core.Utils.joinRhsArity. 2a. Moreover, this same constraint applies to any unfolding of the binder. Reason: if we want to push a continuation into the RHS we must push it into the unfolding as well. 2b. The Arity (in the IdInfo) of a join point varies independently of the join-arity. For example, we could have j x = case x of { T -> \y.y; F -> \y.3 } Its join-arity is 1, but its idArity is 2; and we do not eta-expand join points: see Note [Do not eta-expand join points] in GHC.Core.Opt.Simplify.Utils. Allowing the idArity to be bigger than the join-arity is important in arityType; see GHC.Core.Opt.Arity Note [Arity for recursive join bindings] Historical note: see #17294. 3. If the binding is recursive, then all other bindings in the recursive group must also be join points. 4. The binding's type must not be polymorphic in its return type (as defined in Note [The polymorphism rule of join points]). However, join points have simpler invariants in other ways 5. A join point can have an unboxed type without the RHS being ok-for-speculation (i.e. drop the let-can-float invariant) e.g. let j :: Int# = factorial x in ... 6. The RHS of join point is not required to have a fixed runtime representation, e.g. let j :: r :: TYPE l = fail (##) in ... This happened in an intermediate program #13394 Examples: join j1 x = 1 + x in jump j (jump j x) -- Fails 1: non-tail call join j1' x = 1 + x in if even a then jump j1 a else jump j1 a b -- Fails 1: inconsistent calls join j2 x = flip (+) x in j2 1 2 -- Fails 2: not enough lambdas join j2' x = \y -> x + y in j3 1 -- Passes: extra lams ok join j @a (x :: a) = x -- Fails 4: polymorphic in ret type Invariant 1 applies to left-hand sides of rewrite rules, so a rule for a join point must have an exact call as its LHS. Strictly speaking, invariant 3 is redundant, since a call from inside a lazy binding isn't a tail call. Since a let-bound value can't invoke a free join point, then, they can't be mutually recursive. (A Core binding group *can* include spurious extra bindings if the occurrence analyser hasn't run, so invariant 3 does still need to be checked.) For the rigorous definition of "tail call", see Section 3 of the paper (Note [Join points]). Invariant 4 is subtle; see Note [The polymorphism rule of join points]. Invariant 6 is to enable code like this: f = \(r :: RuntimeRep) (a :: TYPE r) (x :: T). join j :: a j = error @r @a "bloop" in case x of A -> j B -> j C -> error @r @a "blurp" Core Lint will check these invariants, anticipating that any binder whose OccInfo is marked AlwaysTailCalled will become a join point as soon as the simplifier (or simpleOptPgm) runs. Note [Join points are less general than the paper] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In the paper "Compiling without continuations", this expression is perfectly valid: join { j = \_ -> e } in (case blah of ) ( True -> j void# ) arg ( False -> blah ) assuming 'j' has arity 1. Here the call to 'j' does not look like a tail call, but actually everything is fine. See Section 3, "Managing \Delta" in the paper. In GHC, however, we adopt a slightly more restrictive subset, in which join point calls must be tail calls. I think we /could/ loosen it up, but in fact the simplifier ensures that we always get tail calls, and it makes the back end a bit easier I think. Generally, just less to think about; nothing deeper than that. Note [The type of a join point] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A join point has the same type it would have as a function. That is, if it takes an Int and a Bool and its body produces a String, its type is `Int -> Bool -> String`. Natural as this may seem, it can be awkward. A join point shouldn't be thought to "return" in the same sense a function does---a jump is one-way. This is crucial for understanding how case-of-case interacts with join points: case (join j :: Int -> Bool -> String j x y = ... in jump j z w) of "" -> True _ -> False The simplifier will pull the case into the join point (see Note [Join points and case-of-case] in GHC.Core.Opt.Simplify): join j :: Int -> Bool -> Bool -- changed! j x y = case ... of "" -> True _ -> False in jump j z w The body of the join point now returns a Bool, so the label `j` has to have its type updated accordingly, which is done by GHC.Core.Opt.Simplify.Env.adjustJoinPointType. Inconvenient though this may be, it has the advantage that 'GHC.Core.Utils.exprType' can still return a type for any expression, including a jump. Relationship to the paper This plan differs from the paper (see Note [Invariants on join points]). In the paper, we instead give j the type `Int -> Bool -> forall a. a`. Then each jump carries the "return type" as a parameter, exactly the way other non-returning functions like `error` work: case (join j :: Int -> Bool -> forall a. a j x y = ... in jump j z w @String) of "" -> True _ -> False Now we can move the case inward and we only have to change the jump: join j :: Int -> Bool -> forall a. a j x y = case ... of "" -> True _ -> False in jump j z w @Bool (Core Lint would still check that the body of the join point has the right type; that type would simply not be reflected in the join id.) Note [The polymorphism rule of join points] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Invariant 4 of Note [Invariants on join points] forbids a join point to be polymorphic in its return type. That is, if its type is forall a1 ... ak. t1 -> ... -> tn -> r where its join arity is k+n, none of the type parameters ai may occur free in r. In some way, this falls out of the fact that given join j @a1 ... @ak x1 ... xn = e1 in e2 then all calls to `j` are in tail-call positions of `e`, and expressions in tail-call positions in `e` have the same type as `e`. Therefore the type of `e1` -- the return type of the join point -- must be the same as the type of e2. Since the type variables aren't bound in `e2`, its type can't include them, and thus neither can the type of `e1`. This unfortunately prevents the `go` in the following code from being a join-point: iter :: forall a. Int -> (a -> a) -> a -> a iter @a n f x = go @a n f x where go :: forall a. Int -> (a -> a) -> a -> a go @a 0 _ x = x go @a n f x = go @a (n-1) f (f x) In this case, a static argument transformation would fix that (see ticket #14620): iter :: forall a. Int -> (a -> a) -> a -> a iter @a n f x = go' @a n f x where go' :: Int -> (a -> a) -> a -> a go' 0 _ x = x go' n f x = go' (n-1) f (f x) In general, loopification could be employed to do that (see #14068.) Can we simply drop the requirement, and allow `go` to be a join-point? We could, and it would work. But we could not longer apply the case-of-join-point transformation universally. This transformation would do: case (join go @a n f x = case n of 0 -> x n -> go @a (n-1) f (f x) in go @Bool n neg True) of True -> e1; False -> e2 ===> join go @a n f x = case n of 0 -> case x of True -> e1; False -> e2 n -> go @a (n-1) f (f x) in go @Bool n neg True but that is ill-typed, as `x` is type `a`, not `Bool`. This also justifies why we do not consider the `e` in `e |> co` to be in tail position: A cast changes the type, but the type must be the same. But operationally, casts are vacuous, so this is a bit unfortunate! See #14610 for ideas how to fix this. ************************************************************************ * * In/Out type synonyms * * ********************************************************************* -} {- Many passes apply a substitution, and it's very handy to have type synonyms to remind us whether or not the substitution has been applied -} -- Pre-cloning or substitution type InBndr = CoreBndr type InType = Type type InKind = Kind type InBind = CoreBind type InExpr = CoreExpr type InAlt = CoreAlt type InArg = CoreArg type InCoercion = Coercion -- Post-cloning or substitution type OutBndr = CoreBndr type OutType = Type type OutKind = Kind type OutCoercion = Coercion type OutBind = CoreBind type OutExpr = CoreExpr type OutAlt = CoreAlt type OutArg = CoreArg type MOutCoercion = MCoercion {- ************************************************************************ * * Orphans * * ************************************************************************ -} -- | Is this instance an orphan? 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(r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> IsOrphan -> r forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c IsOrphan forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> IsOrphan -> c IsOrphan forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c IsOrphan) forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c IsOrphan) $cgfoldl :: forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> IsOrphan -> c IsOrphan gfoldl :: forall (c :: * -> *). (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> IsOrphan -> c IsOrphan $cgunfold :: forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c IsOrphan gunfold :: forall (c :: * -> *). (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c IsOrphan $ctoConstr :: IsOrphan -> Constr toConstr :: IsOrphan -> Constr $cdataTypeOf :: IsOrphan -> DataType dataTypeOf :: IsOrphan -> DataType $cdataCast1 :: forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c IsOrphan) dataCast1 :: forall (t :: * -> *) (c :: * -> *). Typeable t => (forall d. Data d => c (t d)) -> Maybe (c IsOrphan) $cdataCast2 :: forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c IsOrphan) dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *). Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c IsOrphan) $cgmapT :: (forall b. Data b => b -> b) -> IsOrphan -> IsOrphan gmapT :: (forall b. Data b => b -> b) -> IsOrphan -> IsOrphan $cgmapQl :: forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> IsOrphan -> r gmapQl :: forall r r'. (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> IsOrphan -> r $cgmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> IsOrphan -> r gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> IsOrphan -> r $cgmapQ :: forall u. (forall d. Data d => d -> u) -> IsOrphan -> [u] gmapQ :: forall u. (forall d. Data d => d -> u) -> IsOrphan -> [u] $cgmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> IsOrphan -> u gmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> IsOrphan -> u $cgmapM :: forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan gmapM :: forall (m :: * -> *). Monad m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan $cgmapMp :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan gmapMp :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan $cgmapMo :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan gmapMo :: forall (m :: * -> *). MonadPlus m => (forall d. Data d => d -> m d) -> IsOrphan -> m IsOrphan Data -- | Returns true if 'IsOrphan' is orphan. isOrphan :: IsOrphan -> Bool isOrphan :: IsOrphan -> Bool isOrphan IsOrphan IsOrphan = Bool True isOrphan IsOrphan _ = Bool False -- | Returns true if 'IsOrphan' is not an orphan. notOrphan :: IsOrphan -> Bool notOrphan :: IsOrphan -> Bool notOrphan NotOrphan{} = Bool True notOrphan IsOrphan _ = Bool False chooseOrphanAnchor :: NameSet -> IsOrphan -- Something (rule, instance) is relate to all the Names in this -- list. Choose one of them to be an "anchor" for the orphan. We make -- the choice deterministic to avoid gratuitous changes in the ABI -- hash (#4012). Specifically, use lexicographic comparison of -- OccName rather than comparing Uniques -- -- NB: 'minimum' use Ord, and (Ord OccName) works lexicographically -- chooseOrphanAnchor :: NameSet -> IsOrphan chooseOrphanAnchor NameSet local_names | NameSet -> Bool isEmptyNameSet NameSet local_names = IsOrphan IsOrphan | Bool otherwise = OccName -> IsOrphan NotOrphan ([OccName] -> OccName forall a. Ord a => [a] -> a forall (t :: * -> *) a. (Foldable t, Ord a) => t a -> a minimum [OccName] occs) where occs :: [OccName] occs = (Name -> OccName) -> [Name] -> [OccName] forall a b. (a -> b) -> [a] -> [b] map Name -> OccName nameOccName ([Name] -> [OccName]) -> [Name] -> [OccName] forall a b. (a -> b) -> a -> b $ NameSet -> [Name] forall elt. UniqSet elt -> [elt] nonDetEltsUniqSet NameSet local_names -- It's OK to use nonDetEltsUFM here, see comments above instance Binary IsOrphan where put_ :: BinHandle -> IsOrphan -> IO () put_ BinHandle bh IsOrphan IsOrphan = BinHandle -> Word8 -> IO () putByte BinHandle bh Word8 0 put_ BinHandle bh (NotOrphan OccName n) = do BinHandle -> Word8 -> IO () putByte BinHandle bh Word8 1 BinHandle -> OccName -> IO () forall a. Binary a => BinHandle -> a -> IO () put_ BinHandle bh OccName n get :: BinHandle -> IO IsOrphan get BinHandle bh = do Word8 h <- BinHandle -> IO Word8 getByte BinHandle bh case Word8 h of Word8 0 -> IsOrphan -> IO IsOrphan forall a. a -> IO a forall (m :: * -> *) a. Monad m => a -> m a return IsOrphan IsOrphan Word8 _ -> do OccName n <- BinHandle -> IO OccName forall a. Binary a => BinHandle -> IO a get BinHandle bh IsOrphan -> IO IsOrphan forall a. a -> IO a forall (m :: * -> *) a. Monad m => a -> m a return (IsOrphan -> IO IsOrphan) -> IsOrphan -> IO IsOrphan forall a b. (a -> b) -> a -> b $ OccName -> IsOrphan NotOrphan OccName n {- Note [Orphans] ~~~~~~~~~~~~~~ Class instances, rules, and family instances are divided into orphans and non-orphans. Roughly speaking, an instance/rule is an orphan if its left hand side mentions nothing defined in this module. Orphan-hood has two major consequences * A module that contains orphans is called an "orphan module". If the module being compiled depends (transitively) on an orphan module M, then M.hi is read in regardless of whether M is otherwise needed. This is to ensure that we don't miss any instance decls in M. But it's painful, because it means we need to keep track of all the orphan modules below us. * The "visible orphan modules" are all the orphan module in the transitive closure of the imports of this module. * During instance lookup, we filter orphan instances depending on whether or not the instance is in a visible orphan module. * A non-orphan is not finger-printed separately. Instead, for fingerprinting purposes it is treated as part of the entity it mentions on the LHS. For example data T = T1 | T2 instance Eq T where .... The instance (Eq T) is incorporated as part of T's fingerprint. In contrast, orphans are all fingerprinted together in the mi_orph_hash field of the ModIface. See GHC.Iface.Recomp.addFingerprints. Orphan-hood is computed * For class instances: when we make a ClsInst in GHC.Core.InstEnv.mkLocalInstance (because it is needed during instance lookup) See Note [When exactly is an instance decl an orphan?] in GHC.Core.InstEnv * For rules when we generate a CoreRule (GHC.Core.Rules.mkRule) * For family instances: when we generate an IfaceFamInst (GHC.Iface.Make.instanceToIfaceInst) Orphan-hood is persisted into interface files, in ClsInst, FamInst, and CoreRules. -} {- ************************************************************************ * * \subsection{Rewrite rules} * * ************************************************************************ The CoreRule type and its friends are dealt with mainly in GHC.Core.Rules, but GHC.Core.FVs, GHC.Core.Subst, GHC.Core.Ppr, GHC.Core.Tidy also inspect the representation. -} -- | A 'CoreRule' is: -- -- * \"Local\" if the function it is a rule for is defined in the -- same module as the rule itself. -- -- * \"Orphan\" if nothing on the LHS is defined in the same module -- as the rule itself data CoreRule = Rule { CoreRule -> RuleName ru_name :: RuleName, -- ^ Name of the rule, for communication with the user CoreRule -> Activation ru_act :: Activation, -- ^ When the rule is active -- Rough-matching stuff -- see comments with InstEnv.ClsInst( is_cls, is_rough ) CoreRule -> Name ru_fn :: !Name, -- ^ Name of the 'GHC.Types.Id.Id' at the head of this rule CoreRule -> [Maybe Name] ru_rough :: [Maybe Name], -- ^ Name at the head of each argument to the left hand side -- Proper-matching stuff -- see comments with InstEnv.ClsInst( is_tvs, is_tys ) CoreRule -> [Id] ru_bndrs :: [CoreBndr], -- ^ Variables quantified over CoreRule -> [CoreExpr] ru_args :: [CoreExpr], -- ^ Left hand side arguments -- And the right-hand side CoreRule -> CoreExpr ru_rhs :: CoreExpr, -- ^ Right hand side of the rule -- Occurrence info is guaranteed correct -- See Note [OccInfo in unfoldings and rules] -- Locality CoreRule -> Bool ru_auto :: Bool, -- ^ @True@ <=> this rule is auto-generated -- (notably by Specialise or SpecConstr) -- @False@ <=> generated at the user's behest -- See Note [Trimming auto-rules] in "GHC.Iface.Tidy" -- for the sole purpose of this field. CoreRule -> Module ru_origin :: !Module, -- ^ 'Module' the rule was defined in, used -- to test if we should see an orphan rule. CoreRule -> IsOrphan ru_orphan :: !IsOrphan, -- ^ Whether or not the rule is an orphan. CoreRule -> Bool ru_local :: Bool -- ^ @True@ iff the fn at the head of the rule is -- defined in the same module as the rule -- and is not an implicit 'Id' (like a record selector, -- class operation, or data constructor). This -- is different from 'ru_orphan', where a rule -- can avoid being an orphan if *any* Name in -- LHS of the rule was defined in the same -- module as the rule. } -- | Built-in rules are used for constant folding -- and suchlike. They have no free variables. -- A built-in rule is always visible (there is no such thing as -- an orphan built-in rule.) | BuiltinRule { ru_name :: RuleName, -- ^ As above ru_fn :: Name, -- ^ As above CoreRule -> Arity ru_nargs :: Int, -- ^ Number of arguments that 'ru_try' consumes, -- if it fires, including type arguments CoreRule -> RuleFun ru_try :: RuleFun -- ^ This function does the rewrite. It given too many -- arguments, it simply discards them; the returned 'CoreExpr' -- is just the rewrite of 'ru_fn' applied to the first 'ru_nargs' args } -- See Note [Extra args in the target] in GHC.Core.Rules type RuleFun = RuleOpts -> InScopeEnv -> Id -> [CoreExpr] -> Maybe CoreExpr -- | The 'InScopeSet' in the 'InScopeEnv' is a /superset/ of variables that are -- currently in scope. See Note [The InScopeSet invariant]. data InScopeEnv = ISE InScopeSet IdUnfoldingFun type IdUnfoldingFun = Id -> Unfolding -- A function that embodies how to unfold an Id if you need -- to do that in the Rule. The reason we need to pass this info in -- is that whether an Id is unfoldable depends on the simplifier phase isBuiltinRule :: CoreRule -> Bool isBuiltinRule :: CoreRule -> Bool isBuiltinRule (BuiltinRule {}) = Bool True isBuiltinRule CoreRule _ = Bool False isAutoRule :: CoreRule -> Bool isAutoRule :: CoreRule -> Bool isAutoRule (BuiltinRule {}) = Bool False isAutoRule (Rule { ru_auto :: CoreRule -> Bool ru_auto = Bool is_auto }) = Bool is_auto -- | The number of arguments the 'ru_fn' must be applied -- to before the rule can match on it ruleArity :: CoreRule -> Int ruleArity :: CoreRule -> Arity ruleArity (BuiltinRule {ru_nargs :: CoreRule -> Arity ru_nargs = Arity n}) = Arity n ruleArity (Rule {ru_args :: CoreRule -> [CoreExpr] ru_args = [CoreExpr] args}) = [CoreExpr] -> Arity forall a. [a] -> Arity forall (t :: * -> *) a. Foldable t => t a -> Arity length [CoreExpr] args ruleName :: CoreRule -> RuleName ruleName :: CoreRule -> RuleName ruleName = CoreRule -> RuleName ru_name ruleModule :: CoreRule -> Maybe Module ruleModule :: CoreRule -> Maybe Module ruleModule Rule { Module ru_origin :: CoreRule -> Module ru_origin :: Module ru_origin } = Module -> Maybe Module forall a. a -> Maybe a Just Module ru_origin ruleModule BuiltinRule {} = Maybe Module forall a. Maybe a Nothing ruleActivation :: CoreRule -> Activation ruleActivation :: CoreRule -> Activation ruleActivation (BuiltinRule { }) = Activation AlwaysActive ruleActivation (Rule { ru_act :: CoreRule -> Activation ru_act = Activation act }) = Activation act -- | The 'Name' of the 'GHC.Types.Id.Id' at the head of the rule left hand side ruleIdName :: CoreRule -> Name ruleIdName :: CoreRule -> Name ruleIdName = CoreRule -> Name ru_fn isLocalRule :: CoreRule -> Bool isLocalRule :: CoreRule -> Bool isLocalRule = CoreRule -> Bool ru_local -- | Set the 'Name' of the 'GHC.Types.Id.Id' at the head of the rule left hand side setRuleIdName :: Name -> CoreRule -> CoreRule setRuleIdName :: Name -> CoreRule -> CoreRule setRuleIdName Name nm CoreRule ru = CoreRule ru { ru_fn = nm } {- ************************************************************************ * * Unfoldings * * ************************************************************************ The @Unfolding@ type is declared here to avoid numerous loops Note [Never put `OtherCon` unfoldings on lambda binders] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Based on #21496 we never attach unfoldings of any kind to lambda binders. It's just too easy for the call site to change and invalidate the unfolding. E.g. the caller of the lambda drops a seq (e.g. because the lambda is strict in it's binder) which in turn makes the OtherCon[] unfolding a lie. So unfoldings on lambda binders can never really be trusted when on lambda binders if there is the chance of the call site to change. So it's easiest to just never attach any to lambda binders to begin with, as well as stripping them off if we e.g. float out and expression while abstracting over some arguments. -} -- | Records the /unfolding/ of an identifier, which is approximately the form the -- identifier would have if we substituted its definition in for the identifier. -- This type should be treated as abstract everywhere except in "GHC.Core.Unfold" data Unfolding = NoUnfolding -- ^ We have no information about the unfolding. | BootUnfolding -- ^ We have no information about the unfolding, because -- this 'Id' came from an @hi-boot@ file. -- See Note [Inlining and hs-boot files] in "GHC.CoreToIface" -- for what this is used for. | OtherCon [AltCon] -- ^ It ain't one of these constructors. -- @OtherCon xs@ also indicates that something has been evaluated -- and hence there's no point in re-evaluating it. -- @OtherCon []@ is used even for non-data-type values -- to indicated evaluated-ness. Notably: -- -- > data C = C !(Int -> Int) -- > case x of { C f -> ... } -- -- Here, @f@ gets an @OtherCon []@ unfolding. | DFunUnfolding { -- The Unfolding of a DFunId -- See Note [DFun unfoldings] -- df = /\a1..am. \d1..dn. MkD t1 .. tk -- (op1 a1..am d1..dn) -- (op2 a1..am d1..dn) Unfolding -> [Id] df_bndrs :: [Var], -- The bound variables [a1..m],[d1..dn] Unfolding -> DataCon df_con :: DataCon, -- The dictionary data constructor (never a newtype datacon) Unfolding -> [CoreExpr] df_args :: [CoreExpr] -- Args of the data con: types, superclasses and methods, } -- in positional order | CoreUnfolding { -- An unfolding for an Id with no pragma, -- or perhaps a NOINLINE pragma -- (For NOINLINE, the phase, if any, is in the -- InlinePragInfo for this Id.) Unfolding -> CoreExpr uf_tmpl :: CoreExpr, -- The unfolding itself (aka "template") -- Always occ-analysed; -- See Note [OccInfo in unfoldings and rules] Unfolding -> UnfoldingSource uf_src :: UnfoldingSource, -- Where the unfolding came from Unfolding -> Bool uf_is_top :: Bool, -- True <=> top level binding Unfolding -> UnfoldingCache uf_cache :: UnfoldingCache, -- Cache of flags computable from the expr -- See Note [Tying the 'CoreUnfolding' knot] Unfolding -> UnfoldingGuidance uf_guidance :: UnfoldingGuidance -- Tells about the *size* of the template. } -- ^ An unfolding with redundant cached information. Parameters: -- -- uf_tmpl: Template used to perform unfolding; -- NB: Occurrence info is guaranteed correct: -- see Note [OccInfo in unfoldings and rules] -- -- uf_is_top: Is this a top level binding? -- -- uf_is_value: 'exprIsHNF' template (cached); it is ok to discard a 'seq' on -- this variable -- -- uf_is_work_free: Does this waste only a little work if we expand it inside an inlining? -- Basically this is a cached version of 'exprIsWorkFree' -- -- uf_guidance: Tells us about the /size/ of the unfolding template -- | Properties of a 'CoreUnfolding' that could be computed on-demand from its template. -- See Note [UnfoldingCache] data UnfoldingCache = UnfoldingCache { UnfoldingCache -> Bool uf_is_value :: !Bool, -- exprIsHNF template (cached); it is ok to discard -- a `seq` on this variable UnfoldingCache -> Bool uf_is_conlike :: !Bool, -- True <=> applicn of constructor or CONLIKE function -- Cached version of exprIsConLike UnfoldingCache -> Bool uf_is_work_free :: !Bool, -- True <=> doesn't waste (much) work to expand -- inside an inlining -- Cached version of exprIsCheap UnfoldingCache -> Bool uf_expandable :: !Bool -- True <=> can expand in RULE matching -- Cached version of exprIsExpandable } deriving (UnfoldingCache -> UnfoldingCache -> Bool (UnfoldingCache -> UnfoldingCache -> Bool) -> (UnfoldingCache -> UnfoldingCache -> Bool) -> Eq UnfoldingCache forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a $c== :: UnfoldingCache -> UnfoldingCache -> Bool == :: UnfoldingCache -> UnfoldingCache -> Bool $c/= :: UnfoldingCache -> UnfoldingCache -> Bool /= :: UnfoldingCache -> UnfoldingCache -> Bool Eq) -- | 'UnfoldingGuidance' says when unfolding should take place data UnfoldingGuidance = UnfWhen { -- Inline without thinking about the *size* of the uf_tmpl -- Used (a) for small *and* cheap unfoldings -- (b) for INLINE functions -- See Note [INLINE for small functions] in GHC.Core.Unfold UnfoldingGuidance -> Arity ug_arity :: Arity, -- Number of value arguments expected UnfoldingGuidance -> Bool ug_unsat_ok :: Bool, -- True <=> ok to inline even if unsaturated UnfoldingGuidance -> Bool ug_boring_ok :: Bool -- True <=> ok to inline even if the context is boring -- So True,True means "always" } | UnfIfGoodArgs { -- Arose from a normal Id; the info here is the -- result of a simple analysis of the RHS UnfoldingGuidance -> [Arity] ug_args :: [Int], -- Discount if the argument is evaluated. -- (i.e., a simplification will definitely -- be possible). One elt of the list per *value* arg. UnfoldingGuidance -> Arity ug_size :: Int, -- The "size" of the unfolding. UnfoldingGuidance -> Arity ug_res :: Int -- Scrutinee discount: the discount to subtract if the thing is in } -- a context (case (thing args) of ...), -- (where there are the right number of arguments.) | UnfNever -- The RHS is big, so don't inline it deriving (UnfoldingGuidance -> UnfoldingGuidance -> Bool (UnfoldingGuidance -> UnfoldingGuidance -> Bool) -> (UnfoldingGuidance -> UnfoldingGuidance -> Bool) -> Eq UnfoldingGuidance forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a $c== :: UnfoldingGuidance -> UnfoldingGuidance -> Bool == :: UnfoldingGuidance -> UnfoldingGuidance -> Bool $c/= :: UnfoldingGuidance -> UnfoldingGuidance -> Bool /= :: UnfoldingGuidance -> UnfoldingGuidance -> Bool Eq) {- Note [UnfoldingCache] ~~~~~~~~~~~~~~~~~~~~~~~~ The UnfoldingCache field of an Unfolding holds four (strict) booleans, all derived from the uf_tmpl field of the unfolding. * We serialise the UnfoldingCache to and from interface files, for reasons described in Note [Tying the 'CoreUnfolding' knot] in GHC.IfaceToCore * Because it is a strict data type, we must be careful not to pattern-match on it until we actually want its values. E.g GHC.Core.Unfold.callSiteInline/tryUnfolding are careful not to force it unnecessarily. Just saves a bit of work. * When `seq`ing Core to eliminate space leaks, to suffices to `seq` on the cache, but not its fields, because it is strict in all fields. Note [Historical note: unfoldings for wrappers] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We used to have a nice clever scheme in interface files for wrappers. A wrapper's unfolding can be reconstructed from its worker's id and its strictness. This decreased .hi file size (sometimes significantly, for modules like GHC.Classes with many high-arity w/w splits) and had a slight corresponding effect on compile times. However, when we added the second demand analysis, this scheme lead to some Core lint errors. The second analysis could change the strictness signatures, which sometimes resulted in a wrapper's regenerated unfolding applying the wrapper to too many arguments. Instead of repairing the clever .hi scheme, we abandoned it in favor of simplicity. The .hi sizes are usually insignificant (excluding the +1M for base libraries), and compile time barely increases (~+1% for nofib). The nicer upshot is that the UnfoldingSource no longer mentions an Id, so, eg, substitutions need not traverse them. Note [DFun unfoldings] ~~~~~~~~~~~~~~~~~~~~~~ The Arity in a DFunUnfolding is total number of args (type and value) that the DFun needs to produce a dictionary. That's not necessarily related to the ordinary arity of the dfun Id, esp if the class has one method, so the dictionary is represented by a newtype. Example class C a where { op :: a -> Int } instance C a -> C [a] where op xs = op (head xs) The instance translates to $dfCList :: forall a. C a => C [a] -- Arity 2! $dfCList = /\a.\d. $copList {a} d |> co $copList :: forall a. C a => [a] -> Int -- Arity 2! $copList = /\a.\d.\xs. op {a} d (head xs) Now we might encounter (op (dfCList {ty} d) a1 a2) and we want the (op (dfList {ty} d)) rule to fire, because $dfCList has all its arguments, even though its (value) arity is 2. That's why we record the number of expected arguments in the DFunUnfolding. Note that although it's an Arity, it's most convenient for it to give the *total* number of arguments, both type and value. See the use site in exprIsConApp_maybe. -} -- Constants for the UnfWhen constructor needSaturated, unSaturatedOk :: Bool needSaturated :: Bool needSaturated = Bool False unSaturatedOk :: Bool unSaturatedOk = Bool True boringCxtNotOk, boringCxtOk :: Bool boringCxtOk :: Bool boringCxtOk = Bool True boringCxtNotOk :: Bool boringCxtNotOk = Bool False ------------------------------------------------ noUnfolding :: Unfolding -- ^ There is no known 'Unfolding' evaldUnfolding :: Unfolding -- ^ This unfolding marks the associated thing as being evaluated noUnfolding :: Unfolding noUnfolding = Unfolding NoUnfolding evaldUnfolding :: Unfolding evaldUnfolding = [AltCon] -> Unfolding OtherCon [] -- | There is no known 'Unfolding', because this came from an -- hi-boot file. bootUnfolding :: Unfolding bootUnfolding :: Unfolding bootUnfolding = Unfolding BootUnfolding mkOtherCon :: [AltCon] -> Unfolding mkOtherCon :: [AltCon] -> Unfolding mkOtherCon = [AltCon] -> Unfolding OtherCon -- | Retrieves the template of an unfolding: panics if none is known unfoldingTemplate :: Unfolding -> CoreExpr unfoldingTemplate :: Unfolding -> CoreExpr unfoldingTemplate = Unfolding -> CoreExpr uf_tmpl -- | Retrieves the template of an unfolding if possible -- maybeUnfoldingTemplate is used mainly when specialising, and we do -- want to specialise DFuns, so it's important to return a template -- for DFunUnfoldings maybeUnfoldingTemplate :: Unfolding -> Maybe CoreExpr maybeUnfoldingTemplate :: Unfolding -> Maybe CoreExpr maybeUnfoldingTemplate (CoreUnfolding { uf_tmpl :: Unfolding -> CoreExpr uf_tmpl = CoreExpr expr }) = CoreExpr -> Maybe CoreExpr forall a. a -> Maybe a Just CoreExpr expr maybeUnfoldingTemplate (DFunUnfolding { df_bndrs :: Unfolding -> [Id] df_bndrs = [Id] bndrs, df_con :: Unfolding -> DataCon df_con = DataCon con, df_args :: Unfolding -> [CoreExpr] df_args = [CoreExpr] args }) = CoreExpr -> Maybe CoreExpr forall a. a -> Maybe a Just ([Id] -> CoreExpr -> CoreExpr forall b. [b] -> Expr b -> Expr b mkLams [Id] bndrs (CoreExpr -> [CoreExpr] -> CoreExpr forall b. Expr b -> [Expr b] -> Expr b mkApps (Id -> CoreExpr forall b. Id -> Expr b Var (DataCon -> Id dataConWorkId DataCon con)) [CoreExpr] args)) maybeUnfoldingTemplate Unfolding _ = Maybe CoreExpr forall a. Maybe a Nothing -- | The constructors that the unfolding could never be: -- returns @[]@ if no information is available otherCons :: Unfolding -> [AltCon] otherCons :: Unfolding -> [AltCon] otherCons (OtherCon [AltCon] cons) = [AltCon] cons otherCons Unfolding _ = [] -- | Determines if it is certainly the case that the unfolding will -- yield a value (something in HNF): returns @False@ if unsure isValueUnfolding :: Unfolding -> Bool -- Returns False for OtherCon isValueUnfolding :: Unfolding -> Bool isValueUnfolding (CoreUnfolding { uf_cache :: Unfolding -> UnfoldingCache uf_cache = UnfoldingCache cache }) = UnfoldingCache -> Bool uf_is_value UnfoldingCache cache isValueUnfolding (DFunUnfolding {}) = Bool True isValueUnfolding Unfolding _ = Bool False -- | Determines if it possibly the case that the unfolding will -- yield a value. Unlike 'isValueUnfolding' it returns @True@ -- for 'OtherCon' isEvaldUnfolding :: Unfolding -> Bool -- Returns True for OtherCon isEvaldUnfolding :: Unfolding -> Bool isEvaldUnfolding (OtherCon [AltCon] _) = Bool True isEvaldUnfolding (DFunUnfolding {}) = Bool True isEvaldUnfolding (CoreUnfolding { uf_cache :: Unfolding -> UnfoldingCache uf_cache = UnfoldingCache cache }) = UnfoldingCache -> Bool uf_is_value UnfoldingCache cache isEvaldUnfolding Unfolding _ = Bool False -- | @True@ if the unfolding is a constructor application, the application -- of a CONLIKE function or 'OtherCon' isConLikeUnfolding :: Unfolding -> Bool isConLikeUnfolding :: Unfolding -> Bool isConLikeUnfolding (OtherCon [AltCon] _) = Bool True isConLikeUnfolding (CoreUnfolding { uf_cache :: Unfolding -> UnfoldingCache uf_cache = UnfoldingCache cache }) = UnfoldingCache -> Bool uf_is_conlike UnfoldingCache cache isConLikeUnfolding Unfolding _ = Bool False -- | Is the thing we will unfold into certainly cheap? isCheapUnfolding :: Unfolding -> Bool isCheapUnfolding :: Unfolding -> Bool isCheapUnfolding (CoreUnfolding { uf_cache :: Unfolding -> UnfoldingCache uf_cache = UnfoldingCache cache }) = UnfoldingCache -> Bool uf_is_work_free UnfoldingCache cache isCheapUnfolding Unfolding _ = Bool False isExpandableUnfolding :: Unfolding -> Bool isExpandableUnfolding :: Unfolding -> Bool isExpandableUnfolding (CoreUnfolding { uf_cache :: Unfolding -> UnfoldingCache uf_cache = UnfoldingCache cache }) = UnfoldingCache -> Bool uf_expandable UnfoldingCache cache isExpandableUnfolding Unfolding _ = Bool False expandUnfolding_maybe :: Unfolding -> Maybe CoreExpr -- Expand an expandable unfolding; this is used in rule matching -- See Note [Expanding variables] in GHC.Core.Rules -- The key point here is that CONLIKE things can be expanded expandUnfolding_maybe :: Unfolding -> Maybe CoreExpr expandUnfolding_maybe (CoreUnfolding { uf_cache :: Unfolding -> UnfoldingCache uf_cache = UnfoldingCache cache, uf_tmpl :: Unfolding -> CoreExpr uf_tmpl = CoreExpr rhs }) | UnfoldingCache -> Bool uf_expandable UnfoldingCache cache = CoreExpr -> Maybe CoreExpr forall a. a -> Maybe a Just CoreExpr rhs expandUnfolding_maybe Unfolding _ = Maybe CoreExpr forall a. Maybe a Nothing isCompulsoryUnfolding :: Unfolding -> Bool isCompulsoryUnfolding :: Unfolding -> Bool isCompulsoryUnfolding (CoreUnfolding { uf_src :: Unfolding -> UnfoldingSource uf_src = UnfoldingSource src }) = UnfoldingSource -> Bool isCompulsorySource UnfoldingSource src isCompulsoryUnfolding Unfolding _ = Bool False isStableUnfolding :: Unfolding -> Bool -- True of unfoldings that should not be overwritten -- by a CoreUnfolding for the RHS of a let-binding isStableUnfolding :: Unfolding -> Bool isStableUnfolding (CoreUnfolding { uf_src :: Unfolding -> UnfoldingSource uf_src = UnfoldingSource src }) = UnfoldingSource -> Bool isStableSource UnfoldingSource src isStableUnfolding (DFunUnfolding {}) = Bool True isStableUnfolding Unfolding _ = Bool False isStableUserUnfolding :: Unfolding -> Bool -- True of unfoldings that arise from an INLINE or INLINEABLE pragma isStableUserUnfolding :: Unfolding -> Bool isStableUserUnfolding (CoreUnfolding { uf_src :: Unfolding -> UnfoldingSource uf_src = UnfoldingSource src }) = UnfoldingSource -> Bool isStableUserSource UnfoldingSource src isStableUserUnfolding Unfolding _ = Bool False isStableSystemUnfolding :: Unfolding -> Bool -- True of unfoldings that arise from an INLINE or INLINEABLE pragma isStableSystemUnfolding :: Unfolding -> Bool isStableSystemUnfolding (CoreUnfolding { uf_src :: Unfolding -> UnfoldingSource uf_src = UnfoldingSource src }) = UnfoldingSource -> Bool isStableSystemSource UnfoldingSource src isStableSystemUnfolding Unfolding _ = Bool False isInlineUnfolding :: Unfolding -> Bool -- ^ True of a /stable/ unfolding that is -- (a) always inlined; that is, with an `UnfWhen` guidance, or -- (b) a DFunUnfolding which never needs to be inlined isInlineUnfolding :: Unfolding -> Bool isInlineUnfolding (CoreUnfolding { uf_src :: Unfolding -> UnfoldingSource uf_src = UnfoldingSource src, uf_guidance :: Unfolding -> UnfoldingGuidance uf_guidance = UnfoldingGuidance guidance }) | UnfoldingSource -> Bool isStableSource UnfoldingSource src , UnfWhen {} <- UnfoldingGuidance guidance = Bool True isInlineUnfolding (DFunUnfolding {}) = Bool True -- Default case isInlineUnfolding Unfolding _ = Bool False -- | Only returns False if there is no unfolding information available at all hasSomeUnfolding :: Unfolding -> Bool hasSomeUnfolding :: Unfolding -> Bool hasSomeUnfolding Unfolding NoUnfolding = Bool False hasSomeUnfolding Unfolding BootUnfolding = Bool False hasSomeUnfolding Unfolding _ = Bool True isBootUnfolding :: Unfolding -> Bool isBootUnfolding :: Unfolding -> Bool isBootUnfolding Unfolding BootUnfolding = Bool True isBootUnfolding Unfolding _ = Bool False neverUnfoldGuidance :: UnfoldingGuidance -> Bool neverUnfoldGuidance :: UnfoldingGuidance -> Bool neverUnfoldGuidance UnfoldingGuidance UnfNever = Bool True neverUnfoldGuidance UnfoldingGuidance _ = Bool False hasCoreUnfolding :: Unfolding -> Bool -- An unfolding "has Core" if it contains a Core expression, which -- may mention free variables. See Note [Fragile unfoldings] hasCoreUnfolding :: Unfolding -> Bool hasCoreUnfolding (CoreUnfolding {}) = Bool True hasCoreUnfolding (DFunUnfolding {}) = Bool True hasCoreUnfolding Unfolding _ = Bool False -- NoUnfolding, BootUnfolding, OtherCon have no Core canUnfold :: Unfolding -> Bool canUnfold :: Unfolding -> Bool canUnfold (CoreUnfolding { uf_guidance :: Unfolding -> UnfoldingGuidance uf_guidance = UnfoldingGuidance g }) = Bool -> Bool not (UnfoldingGuidance -> Bool neverUnfoldGuidance UnfoldingGuidance g) canUnfold Unfolding _ = Bool False {- Note [Fragile unfoldings] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ An unfolding is "fragile" if it mentions free variables (and hence would need substitution) or might be affected by optimisation. The non-fragile ones are NoUnfolding, BootUnfolding OtherCon {} If we know this binder (say a lambda binder) will be bound to an evaluated thing, we want to retain that info in simpleOptExpr; see #13077. We consider even a StableUnfolding as fragile, because it needs substitution. Note [Stable unfoldings] ~~~~~~~~~~~~~~~~~~~~~~~~ When you say {-# INLINE f #-} f x = <rhs> you intend that calls (f e) are replaced by <rhs>[e/x] So we should capture (\x.<rhs>) in the Unfolding of 'f', and never meddle with it. Meanwhile, we can optimise <rhs> to our heart's content, leaving the original unfolding intact in Unfolding of 'f'. For example all xs = foldr (&&) True xs any p = all . map p {-# INLINE any #-} We optimise any's RHS fully, but leave the stable unfolding for `any` saying "all . map p", which deforests well at the call site. So INLINE pragma gives rise to a stable unfolding, which captures the original RHS. Moreover, it's only used when 'f' is applied to the specified number of arguments; that is, the number of argument on the LHS of the '=' sign in the original source definition. For example, (.) is now defined in the libraries like this {-# INLINE (.) #-} (.) f g = \x -> f (g x) so that it'll inline when applied to two arguments. If 'x' appeared on the left, thus (.) f g x = f (g x) it'd only inline when applied to three arguments. This slightly-experimental change was requested by Roman, but it seems to make sense. Note [OccInfo in unfoldings and rules] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In unfoldings and rules, we guarantee that the template is occ-analysed, so that the occurrence info on the binders is correct. That way, when the Simplifier inlines an unfolding, it doesn't need to occ-analysis it first. (The Simplifier is designed to simplify occ-analysed expressions.) Given this decision it's vital that we do *always* do it. * If we don't, we may get more simplifier iterations than necessary, because once-occ info isn't there * More seriously, we may get an infinite loop if there's a Rec without a loop breaker marked. * Or we may get code that mentions variables not in scope: #22761 e.g. Suppose we have a stable unfolding : \y. let z = p+1 in 3 Then the pre-simplifier occ-anal will occ-anal the unfolding (redundantly perhaps, but we need its free vars); this will not report the use of `p`; so p's binding will be discarded, and yet `p` is still mentioned. Better to occ-anal the unfolding at birth, which will drop the z-binding as dead code. (Remember, it's the occurrence analyser that drops dead code.) * Another example is #8892: \x -> letrec { f = ...g...; g* = f } in body where g* is (for some strange reason) the loop breaker. If we don't occ-anal it when reading it in, we won't mark g as a loop breaker, and we may inline g entirely in body, dropping its binding, and leaving the occurrence in f out of scope. This happened in #8892, where the unfolding in question was a DFun unfolding. ************************************************************************ * * AltCon * * ************************************************************************ -} -- The Ord is needed for the FiniteMap used in the lookForConstructor -- in GHC.Core.Opt.Simplify.Env. If you declared that lookForConstructor -- *ignores* constructor-applications with LitArg args, then you could get rid -- of this Ord. instance Outputable AltCon where ppr :: AltCon -> SDoc ppr (DataAlt DataCon dc) = DataCon -> SDoc forall a. Outputable a => a -> SDoc ppr DataCon dc ppr (LitAlt Literal lit) = Literal -> SDoc forall a. Outputable a => a -> SDoc ppr Literal lit ppr AltCon DEFAULT = String -> SDoc forall doc. IsLine doc => String -> doc text String "__DEFAULT" cmpAlt :: Alt a -> Alt a -> Ordering cmpAlt :: forall a. Alt a -> Alt a -> Ordering cmpAlt (Alt AltCon con1 [a] _ Expr a _) (Alt AltCon con2 [a] _ Expr a _) = AltCon con1 AltCon -> AltCon -> Ordering `cmpAltCon` AltCon con2 ltAlt :: Alt a -> Alt a -> Bool ltAlt :: forall a. Alt a -> Alt a -> Bool ltAlt Alt a a1 Alt a a2 = (Alt a a1 Alt a -> Alt a -> Ordering forall a. Alt a -> Alt a -> Ordering `cmpAlt` Alt a a2) Ordering -> Ordering -> Bool forall a. Eq a => a -> a -> Bool == Ordering LT cmpAltCon :: AltCon -> AltCon -> Ordering -- ^ Compares 'AltCon's within a single list of alternatives -- DEFAULT comes out smallest, so that sorting by AltCon puts -- alternatives in the order required: see Note [Case expression invariants] cmpAltCon :: AltCon -> AltCon -> Ordering cmpAltCon AltCon DEFAULT AltCon DEFAULT = Ordering EQ cmpAltCon AltCon DEFAULT AltCon _ = Ordering LT cmpAltCon (DataAlt DataCon d1) (DataAlt DataCon d2) = DataCon -> Arity dataConTag DataCon d1 Arity -> Arity -> Ordering forall a. Ord a => a -> a -> Ordering `compare` DataCon -> Arity dataConTag DataCon d2 cmpAltCon (DataAlt DataCon _) AltCon DEFAULT = Ordering GT cmpAltCon (LitAlt Literal l1) (LitAlt Literal l2) = Literal l1 Literal -> Literal -> Ordering forall a. Ord a => a -> a -> Ordering `compare` Literal l2 cmpAltCon (LitAlt Literal _) AltCon DEFAULT = Ordering GT cmpAltCon AltCon con1 AltCon con2 = String -> SDoc -> Ordering forall a. HasCallStack => String -> SDoc -> a pprPanic String "cmpAltCon" (AltCon -> SDoc forall a. Outputable a => a -> SDoc ppr AltCon con1 SDoc -> SDoc -> SDoc forall doc. IsDoc doc => doc -> doc -> doc $$ AltCon -> SDoc forall a. Outputable a => a -> SDoc ppr AltCon con2) {- ************************************************************************ * * \subsection{Useful synonyms} * * ************************************************************************ Note [CoreProgram] ~~~~~~~~~~~~~~~~~~ The top level bindings of a program, a CoreProgram, are represented as a list of CoreBind * Later bindings in the list can refer to earlier ones, but not vice versa. So this is OK NonRec { x = 4 } Rec { p = ...q...x... ; q = ...p...x } Rec { f = ...p..x..f.. } NonRec { g = ..f..q...x.. } But it would NOT be ok for 'f' to refer to 'g'. * The occurrence analyser does strongly-connected component analysis on each Rec binding, and splits it into a sequence of smaller bindings where possible. So the program typically starts life as a single giant Rec, which is then dependency-analysed into smaller chunks. -} -- If you edit this type, you may need to update the GHC formalism -- See Note [GHC Formalism] in GHC.Core.Lint type CoreProgram = [CoreBind] -- See Note [CoreProgram] -- | The common case for the type of binders and variables when -- we are manipulating the Core language within GHC type CoreBndr = Var -- | Expressions where binders are 'CoreBndr's type CoreExpr = Expr CoreBndr -- | Argument expressions where binders are 'CoreBndr's type CoreArg = Arg CoreBndr -- | Binding groups where binders are 'CoreBndr's type CoreBind = Bind CoreBndr -- | Case alternatives where binders are 'CoreBndr's type CoreAlt = Alt CoreBndr {- ************************************************************************ * * \subsection{Tagging} * * ************************************************************************ -} -- | Binders are /tagged/ with a t data TaggedBndr t = TB CoreBndr t -- TB for "tagged binder" type TaggedBind t = Bind (TaggedBndr t) type TaggedExpr t = Expr (TaggedBndr t) type TaggedArg t = Arg (TaggedBndr t) type TaggedAlt t = Alt (TaggedBndr t) instance Outputable b => Outputable (TaggedBndr b) where ppr :: TaggedBndr b -> SDoc ppr (TB Id b b l) = Char -> SDoc forall doc. IsLine doc => Char -> doc char Char '<' SDoc -> SDoc -> SDoc forall doc. IsLine doc => doc -> doc -> doc <> Id -> SDoc forall a. Outputable a => a -> SDoc ppr Id b SDoc -> SDoc -> SDoc forall doc. IsLine doc => doc -> doc -> doc <> SDoc forall doc. IsLine doc => doc comma SDoc -> SDoc -> SDoc forall doc. IsLine doc => doc -> doc -> doc <> b -> SDoc forall a. Outputable a => a -> SDoc ppr b l SDoc -> SDoc -> SDoc forall doc. IsLine doc => doc -> doc -> doc <> Char -> SDoc forall doc. IsLine doc => Char -> doc char Char '>' deTagExpr :: TaggedExpr t -> CoreExpr deTagExpr :: forall t. TaggedExpr t -> CoreExpr deTagExpr (Var Id v) = Id -> CoreExpr forall b. Id -> Expr b Var Id v deTagExpr (Lit Literal l) = Literal -> CoreExpr forall b. Literal -> Expr b Lit Literal l deTagExpr (Type Type ty) = Type -> CoreExpr forall b. Type -> Expr b Type Type ty deTagExpr (Coercion CoercionR co) = CoercionR -> CoreExpr forall b. CoercionR -> Expr b Coercion CoercionR co deTagExpr (App Expr (TaggedBndr t) e1 Expr (TaggedBndr t) e2) = CoreExpr -> CoreExpr -> CoreExpr forall b. Expr b -> Expr b -> Expr b App (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) e1) (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) e2) deTagExpr (Lam (TB Id b t _) Expr (TaggedBndr t) e) = Id -> CoreExpr -> CoreExpr forall b. b -> Expr b -> Expr b Lam Id b (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) e) deTagExpr (Let Bind (TaggedBndr t) bind Expr (TaggedBndr t) body) = Bind Id -> CoreExpr -> CoreExpr forall b. Bind b -> Expr b -> Expr b Let (Bind (TaggedBndr t) -> Bind Id forall t. TaggedBind t -> Bind Id deTagBind Bind (TaggedBndr t) bind) (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) body) deTagExpr (Case Expr (TaggedBndr t) e (TB Id b t _) Type ty [Alt (TaggedBndr t)] alts) = CoreExpr -> Id -> Type -> [Alt Id] -> CoreExpr forall b. Expr b -> b -> Type -> [Alt b] -> Expr b Case (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) e) Id b Type ty ((Alt (TaggedBndr t) -> Alt Id) -> [Alt (TaggedBndr t)] -> [Alt Id] forall a b. (a -> b) -> [a] -> [b] map Alt (TaggedBndr t) -> Alt Id forall t. TaggedAlt t -> Alt Id deTagAlt [Alt (TaggedBndr t)] alts) deTagExpr (Tick CoreTickish t Expr (TaggedBndr t) e) = CoreTickish -> CoreExpr -> CoreExpr forall b. CoreTickish -> Expr b -> Expr b Tick CoreTickish t (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) e) deTagExpr (Cast Expr (TaggedBndr t) e CoercionR co) = CoreExpr -> CoercionR -> CoreExpr forall b. Expr b -> CoercionR -> Expr b Cast (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) e) CoercionR co deTagBind :: TaggedBind t -> CoreBind deTagBind :: forall t. TaggedBind t -> Bind Id deTagBind (NonRec (TB Id b t _) Expr (TaggedBndr t) rhs) = Id -> CoreExpr -> Bind Id forall b. b -> Expr b -> Bind b NonRec Id b (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) rhs) deTagBind (Rec [(TaggedBndr t, Expr (TaggedBndr t))] prs) = [(Id, CoreExpr)] -> Bind Id forall b. [(b, Expr b)] -> Bind b Rec [(Id b, Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) rhs) | (TB Id b t _, Expr (TaggedBndr t) rhs) <- [(TaggedBndr t, Expr (TaggedBndr t))] prs] deTagAlt :: TaggedAlt t -> CoreAlt deTagAlt :: forall t. TaggedAlt t -> Alt Id deTagAlt (Alt AltCon con [TaggedBndr t] bndrs Expr (TaggedBndr t) rhs) = AltCon -> [Id] -> CoreExpr -> Alt Id forall b. AltCon -> [b] -> Expr b -> Alt b Alt AltCon con [Id b | TB Id b t _ <- [TaggedBndr t] bndrs] (Expr (TaggedBndr t) -> CoreExpr forall t. TaggedExpr t -> CoreExpr deTagExpr Expr (TaggedBndr t) rhs) {- ************************************************************************ * * \subsection{Core-constructing functions with checking} * * ************************************************************************ -} -- | Apply a list of argument expressions to a function expression in a nested fashion. Prefer to -- use 'GHC.Core.Make.mkCoreApps' if possible mkApps :: Expr b -> [Arg b] -> Expr b -- | Apply a list of type argument expressions to a function expression in a nested fashion mkTyApps :: Expr b -> [Type] -> Expr b -- | Apply a list of coercion argument expressions to a function expression in a nested fashion mkCoApps :: Expr b -> [Coercion] -> Expr b -- | Apply a list of type or value variables to a function expression in a nested fashion mkVarApps :: Expr b -> [Var] -> Expr b -- | Apply a list of argument expressions to a data constructor in a nested fashion. Prefer to -- use 'GHC.Core.Make.mkCoreConApps' if possible mkConApp :: DataCon -> [Arg b] -> Expr b mkApps :: forall b. Expr b -> [Expr b] -> Expr b mkApps Expr b f [Expr b] args = (Expr b -> Expr b -> Expr b) -> Expr b -> [Expr b] -> Expr b forall b a. (b -> a -> b) -> b -> [a] -> b forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl' Expr b -> Expr b -> Expr b forall b. Expr b -> Expr b -> Expr b App Expr b f [Expr b] args mkCoApps :: forall b. Expr b -> [CoercionR] -> Expr b mkCoApps Expr b f [CoercionR] args = (Expr b -> CoercionR -> Expr b) -> Expr b -> [CoercionR] -> Expr b forall b a. (b -> a -> b) -> b -> [a] -> b forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl' (\ Expr b e CoercionR a -> Expr b -> Expr b -> Expr b forall b. Expr b -> Expr b -> Expr b App Expr b e (CoercionR -> Expr b forall b. CoercionR -> Expr b Coercion CoercionR a)) Expr b f [CoercionR] args mkVarApps :: forall b. Expr b -> [Id] -> Expr b mkVarApps Expr b f [Id] vars = (Expr b -> Id -> Expr b) -> Expr b -> [Id] -> Expr b forall b a. (b -> a -> b) -> b -> [a] -> b forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl' (\ Expr b e Id a -> Expr b -> Expr b -> Expr b forall b. Expr b -> Expr b -> Expr b App Expr b e (Id -> Expr b forall b. Id -> Expr b varToCoreExpr Id a)) Expr b f [Id] vars mkConApp :: forall b. DataCon -> [Arg b] -> Arg b mkConApp DataCon con [Arg b] args = Arg b -> [Arg b] -> Arg b forall b. Expr b -> [Expr b] -> Expr b mkApps (Id -> Arg b forall b. Id -> Expr b Var (DataCon -> Id dataConWorkId DataCon con)) [Arg b] args mkTyApps :: forall b. Expr b -> [Type] -> Expr b mkTyApps Expr b f [Type] args = (Expr b -> Type -> Expr b) -> Expr b -> [Type] -> Expr b forall b a. (b -> a -> b) -> b -> [a] -> b forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl' (\ Expr b e Type a -> Expr b -> Expr b -> Expr b forall b. Expr b -> Expr b -> Expr b App Expr b e (Type -> Expr b forall b. Type -> Expr b mkTyArg Type a)) Expr b f [Type] args mkConApp2 :: DataCon -> [Type] -> [Var] -> Expr b mkConApp2 :: forall b. DataCon -> [Type] -> [Id] -> Expr b mkConApp2 DataCon con [Type] tys [Id] arg_ids = Id -> Expr b forall b. Id -> Expr b Var (DataCon -> Id dataConWorkId DataCon con) Expr b -> [Expr b] -> Expr b forall b. Expr b -> [Expr b] -> Expr b `mkApps` (Type -> Expr b) -> [Type] -> [Expr b] forall a b. (a -> b) -> [a] -> [b] map Type -> Expr b forall b. Type -> Expr b Type [Type] tys Expr b -> [Expr b] -> Expr b forall b. Expr b -> [Expr b] -> Expr b `mkApps` (Id -> Expr b) -> [Id] -> [Expr b] forall a b. (a -> b) -> [a] -> [b] map Id -> Expr b forall b. Id -> Expr b varToCoreExpr [Id] arg_ids mkTyArg :: Type -> Expr b mkTyArg :: forall b. Type -> Expr b mkTyArg Type ty | Just CoercionR co <- Type -> Maybe CoercionR isCoercionTy_maybe Type ty = CoercionR -> Expr b forall b. CoercionR -> Expr b Coercion CoercionR co | Bool otherwise = Type -> Expr b forall b. Type -> Expr b Type Type ty -- | Create a machine integer literal expression of type @Int#@ from an @Integer@. -- If you want an expression of type @Int@ use 'GHC.Core.Make.mkIntExpr' mkIntLit :: Platform -> Integer -> Expr b mkIntLit :: forall b. Platform -> Integer -> Expr b mkIntLit Platform platform Integer n = Literal -> Expr b forall b. Literal -> Expr b Lit (Platform -> Integer -> Literal mkLitInt Platform platform Integer n) -- | Create a machine integer literal expression of type @Int#@ from an -- @Integer@, wrapping if necessary. -- If you want an expression of type @Int@ use 'GHC.Core.Make.mkIntExpr' mkIntLitWrap :: Platform -> Integer -> Expr b mkIntLitWrap :: forall b. Platform -> Integer -> Expr b mkIntLitWrap Platform platform Integer n = Literal -> Expr b forall b. Literal -> Expr b Lit (Platform -> Integer -> Literal mkLitIntWrap Platform platform Integer n) -- | Create a machine word literal expression of type @Word#@ from an @Integer@. -- If you want an expression of type @Word@ use 'GHC.Core.Make.mkWordExpr' mkWordLit :: Platform -> Integer -> Expr b mkWordLit :: forall b. Platform -> Integer -> Expr b mkWordLit Platform platform Integer w = Literal -> Expr b forall b. Literal -> Expr b Lit (Platform -> Integer -> Literal mkLitWord Platform platform Integer w) -- | Create a machine word literal expression of type @Word#@ from an -- @Integer@, wrapping if necessary. -- If you want an expression of type @Word@ use 'GHC.Core.Make.mkWordExpr' mkWordLitWrap :: Platform -> Integer -> Expr b mkWordLitWrap :: forall b. Platform -> Integer -> Expr b mkWordLitWrap Platform platform Integer w = Literal -> Expr b forall b. Literal -> Expr b Lit (Platform -> Integer -> Literal mkLitWordWrap Platform platform Integer w) mkWord8Lit :: Integer -> Expr b mkWord8Lit :: forall b. Integer -> Expr b mkWord8Lit Integer w = Literal -> Expr b forall b. Literal -> Expr b Lit (Integer -> Literal mkLitWord8 Integer w) mkWord64LitWord64 :: Word64 -> Expr b mkWord64LitWord64 :: forall b. Word64 -> Expr b mkWord64LitWord64 Word64 w = Literal -> Expr b forall b. Literal -> Expr b Lit (Integer -> Literal mkLitWord64 (Word64 -> Integer forall a. Integral a => a -> Integer toInteger Word64 w)) mkInt64LitInt64 :: Int64 -> Expr b mkInt64LitInt64 :: forall b. Int64 -> Expr b mkInt64LitInt64 Int64 w = Literal -> Expr b forall b. Literal -> Expr b Lit (Integer -> Literal mkLitInt64 (Int64 -> Integer forall a. Integral a => a -> Integer toInteger Int64 w)) -- | Create a machine character literal expression of type @Char#@. -- If you want an expression of type @Char@ use 'GHC.Core.Make.mkCharExpr' mkCharLit :: Char -> Expr b -- | Create a machine string literal expression of type @Addr#@. -- If you want an expression of type @String@ use 'GHC.Core.Make.mkStringExpr' mkStringLit :: String -> Expr b mkCharLit :: forall b. Char -> Expr b mkCharLit Char c = Literal -> Expr b forall b. Literal -> Expr b Lit (Char -> Literal mkLitChar Char c) mkStringLit :: forall b. String -> Expr b mkStringLit String s = Literal -> Expr b forall b. Literal -> Expr b Lit (String -> Literal mkLitString String s) -- | Create a machine single precision literal expression of type @Float#@ from a @Rational@. -- If you want an expression of type @Float@ use 'GHC.Core.Make.mkFloatExpr' mkFloatLit :: Rational -> Expr b -- | Create a machine single precision literal expression of type @Float#@ from a @Float@. -- If you want an expression of type @Float@ use 'GHC.Core.Make.mkFloatExpr' mkFloatLitFloat :: Float -> Expr b mkFloatLit :: forall b. Rational -> Expr b mkFloatLit Rational f = Literal -> Expr b forall b. Literal -> Expr b Lit (Rational -> Literal mkLitFloat Rational f) mkFloatLitFloat :: forall b. Float -> Expr b mkFloatLitFloat Float f = Literal -> Expr b forall b. Literal -> Expr b Lit (Rational -> Literal mkLitFloat (Float -> Rational forall a. Real a => a -> Rational toRational Float f)) -- | Create a machine double precision literal expression of type @Double#@ from a @Rational@. -- If you want an expression of type @Double@ use 'GHC.Core.Make.mkDoubleExpr' mkDoubleLit :: Rational -> Expr b -- | Create a machine double precision literal expression of type @Double#@ from a @Double@. -- If you want an expression of type @Double@ use 'GHC.Core.Make.mkDoubleExpr' mkDoubleLitDouble :: Double -> Expr b mkDoubleLit :: forall b. Rational -> Expr b mkDoubleLit Rational d = Literal -> Expr b forall b. Literal -> Expr b Lit (Rational -> Literal mkLitDouble Rational d) mkDoubleLitDouble :: forall b. Double -> Expr b mkDoubleLitDouble Double d = Literal -> Expr b forall b. Literal -> Expr b Lit (Rational -> Literal mkLitDouble (Double -> Rational forall a. Real a => a -> Rational toRational Double d)) -- | Bind all supplied binding groups over an expression in a nested let expression. Assumes -- that the rhs satisfies the let-can-float invariant. Prefer to use -- 'GHC.Core.Make.mkCoreLets' if possible, which does guarantee the invariant mkLets :: [Bind b] -> Expr b -> Expr b -- | Bind all supplied binders over an expression in a nested lambda expression. Prefer to -- use 'GHC.Core.Make.mkCoreLams' if possible mkLams :: [b] -> Expr b -> Expr b mkLams :: forall b. [b] -> Expr b -> Expr b mkLams [b] binders Expr b body = (b -> Expr b -> Expr b) -> Expr b -> [b] -> Expr b forall a b. (a -> b -> b) -> b -> [a] -> b forall (t :: * -> *) a b. Foldable t => (a -> b -> b) -> b -> t a -> b foldr b -> Expr b -> Expr b forall b. b -> Expr b -> Expr b Lam Expr b body [b] binders mkLets :: forall b. [Bind b] -> Expr b -> Expr b mkLets [Bind b] binds Expr b body = (Bind b -> Expr b -> Expr b) -> Expr b -> [Bind b] -> Expr b forall a b. (a -> b -> b) -> b -> [a] -> b forall (t :: * -> *) a b. Foldable t => (a -> b -> b) -> b -> t a -> b foldr Bind b -> Expr b -> Expr b forall b. Bind b -> Expr b -> Expr b mkLet Expr b body [Bind b] binds mkLet :: Bind b -> Expr b -> Expr b -- The desugarer sometimes generates an empty Rec group -- which Lint rejects, so we kill it off right away mkLet :: forall b. Bind b -> Expr b -> Expr b mkLet (Rec []) Expr b body = Expr b body mkLet Bind b bind Expr b body = Bind b -> Expr b -> Expr b forall b. Bind b -> Expr b -> Expr b Let Bind b bind Expr b body -- | @mkLetNonRec bndr rhs body@ wraps @body@ in a @let@ binding @bndr@. mkLetNonRec :: b -> Expr b -> Expr b -> Expr b mkLetNonRec :: forall b. b -> Expr b -> Expr b -> Expr b mkLetNonRec b b Expr b rhs Expr b body = Bind b -> Expr b -> Expr b forall b. Bind b -> Expr b -> Expr b Let (b -> Expr b -> Bind b forall b. b -> Expr b -> Bind b NonRec b b Expr b rhs) Expr b body -- | @mkLetRec binds body@ wraps @body@ in a @let rec@ with the given set of -- @binds@ if binds is non-empty. mkLetRec :: [(b, Expr b)] -> Expr b -> Expr b mkLetRec :: forall b. [(b, Expr b)] -> Expr b -> Expr b mkLetRec [] Expr b body = Expr b body mkLetRec [(b, Expr b)] bs Expr b body = Bind b -> Expr b -> Expr b forall b. Bind b -> Expr b -> Expr b Let ([(b, Expr b)] -> Bind b forall b. [(b, Expr b)] -> Bind b Rec [(b, Expr b)] bs) Expr b body -- | Create a binding group where a type variable is bound to a type. -- Per Note [Core type and coercion invariant], -- this can only be used to bind something in a non-recursive @let@ expression mkTyBind :: TyVar -> Type -> CoreBind mkTyBind :: Id -> Type -> Bind Id mkTyBind Id tv Type ty = Id -> CoreExpr -> Bind Id forall b. b -> Expr b -> Bind b NonRec Id tv (Type -> CoreExpr forall b. Type -> Expr b Type Type ty) -- | Create a binding group where a type variable is bound to a type. -- Per Note [Core type and coercion invariant], -- this can only be used to bind something in a non-recursive @let@ expression mkCoBind :: CoVar -> Coercion -> CoreBind mkCoBind :: Id -> CoercionR -> Bind Id mkCoBind Id cv CoercionR co = Id -> CoreExpr -> Bind Id forall b. b -> Expr b -> Bind b NonRec Id cv (CoercionR -> CoreExpr forall b. CoercionR -> Expr b Coercion CoercionR co) -- | Convert a binder into either a 'Var' or 'Type' 'Expr' appropriately varToCoreExpr :: CoreBndr -> Expr b varToCoreExpr :: forall b. Id -> Expr b varToCoreExpr Id v | Id -> Bool isTyVar Id v = Type -> Expr b forall b. Type -> Expr b Type (Id -> Type mkTyVarTy Id v) | Id -> Bool isCoVar Id v = CoercionR -> Expr b forall b. CoercionR -> Expr b Coercion (Id -> CoercionR mkCoVarCo Id v) | Bool otherwise = Bool -> Expr b -> Expr b forall a. HasCallStack => Bool -> a -> a assert (Id -> Bool isId Id v) (Expr b -> Expr b) -> Expr b -> Expr b forall a b. (a -> b) -> a -> b $ Id -> Expr b forall b. Id -> Expr b Var Id v varsToCoreExprs :: [CoreBndr] -> [Expr b] varsToCoreExprs :: forall b. [Id] -> [Expr b] varsToCoreExprs [Id] vs = (Id -> Expr b) -> [Id] -> [Expr b] forall a b. (a -> b) -> [a] -> [b] map Id -> Expr b forall b. Id -> Expr b varToCoreExpr [Id] vs {- ************************************************************************ * * Getting a result type * * ************************************************************************ These are defined here to avoid a module loop between GHC.Core.Utils and GHC.Core.FVs -} -- | If the expression is a 'Type', converts. Otherwise, -- panics. NB: This does /not/ convert 'Coercion' to 'CoercionTy'. exprToType :: CoreExpr -> Type exprToType :: CoreExpr -> Type exprToType (Type Type ty) = Type ty exprToType CoreExpr _bad = String -> SDoc -> Type forall a. HasCallStack => String -> SDoc -> a pprPanic String "exprToType" SDoc forall doc. IsOutput doc => doc empty {- ************************************************************************ * * \subsection{Simple access functions} * * ************************************************************************ -} -- | Extract every variable by this group bindersOf :: Bind b -> [b] -- If you edit this function, you may need to update the GHC formalism -- See Note [GHC Formalism] in GHC.Core.Lint bindersOf :: forall b. Bind b -> [b] bindersOf (NonRec b binder Expr b _) = [b binder] bindersOf (Rec [(b, Expr b)] pairs) = [b binder | (b binder, Expr b _) <- [(b, Expr b)] pairs] -- | 'bindersOf' applied to a list of binding groups bindersOfBinds :: [Bind b] -> [b] bindersOfBinds :: forall b. [Bind b] -> [b] bindersOfBinds [Bind b] binds = (Bind b -> [b] -> [b]) -> [b] -> [Bind b] -> [b] forall a b. (a -> b -> b) -> b -> [a] -> b forall (t :: * -> *) a b. Foldable t => (a -> b -> b) -> b -> t a -> b foldr ([b] -> [b] -> [b] forall a. [a] -> [a] -> [a] (++) ([b] -> [b] -> [b]) -> (Bind b -> [b]) -> Bind b -> [b] -> [b] forall b c a. (b -> c) -> (a -> b) -> a -> c . Bind b -> [b] forall b. Bind b -> [b] bindersOf) [] [Bind b] binds -- We inline this to avoid unknown function calls. {-# INLINE foldBindersOfBindStrict #-} foldBindersOfBindStrict :: (a -> b -> a) -> a -> Bind b -> a foldBindersOfBindStrict :: forall a b. (a -> b -> a) -> a -> Bind b -> a foldBindersOfBindStrict a -> b -> a f = \a z Bind b bind -> case Bind b bind of NonRec b b Expr b _rhs -> a -> b -> a f a z b b Rec [(b, Expr b)] pairs -> (a -> b -> a) -> a -> [b] -> a forall b a. (b -> a -> b) -> b -> [a] -> b forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl' a -> b -> a f a z ([b] -> a) -> [b] -> a forall a b. (a -> b) -> a -> b $ ((b, Expr b) -> b) -> [(b, Expr b)] -> [b] forall a b. (a -> b) -> [a] -> [b] map (b, Expr b) -> b forall a b. (a, b) -> a fst [(b, Expr b)] pairs {-# INLINE foldBindersOfBindsStrict #-} foldBindersOfBindsStrict :: (a -> b -> a) -> a -> [Bind b] -> a foldBindersOfBindsStrict :: forall a b. (a -> b -> a) -> a -> [Bind b] -> a foldBindersOfBindsStrict a -> b -> a f = \a z [Bind b] binds -> (a -> Bind b -> a) -> a -> [Bind b] -> a forall b a. (b -> a -> b) -> b -> [a] -> b forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl' a -> Bind b -> a fold_bind a z [Bind b] binds where fold_bind :: a -> Bind b -> a fold_bind = ((a -> b -> a) -> a -> Bind b -> a forall a b. (a -> b -> a) -> a -> Bind b -> a foldBindersOfBindStrict a -> b -> a f) rhssOfBind :: Bind b -> [Expr b] rhssOfBind :: forall b. Bind b -> [Expr b] rhssOfBind (NonRec b _ Expr b rhs) = [Expr b rhs] rhssOfBind (Rec [(b, Expr b)] pairs) = [Expr b rhs | (b _,Expr b rhs) <- [(b, Expr b)] pairs] rhssOfAlts :: [Alt b] -> [Expr b] rhssOfAlts :: forall b. [Alt b] -> [Expr b] rhssOfAlts [Alt b] alts = [Expr b e | Alt AltCon _ [b] _ Expr b e <- [Alt b] alts] -- | Collapse all the bindings in the supplied groups into a single -- list of lhs\/rhs pairs suitable for binding in a 'Rec' binding group flattenBinds :: [Bind b] -> [(b, Expr b)] flattenBinds :: forall b. [Bind b] -> [(b, Expr b)] flattenBinds (NonRec b b Expr b r : [Bind b] binds) = (b b,Expr b r) (b, Expr b) -> [(b, Expr b)] -> [(b, Expr b)] forall a. a -> [a] -> [a] : [Bind b] -> [(b, Expr b)] forall b. [Bind b] -> [(b, Expr b)] flattenBinds [Bind b] binds flattenBinds (Rec [(b, Expr b)] prs1 : [Bind b] binds) = [(b, Expr b)] prs1 [(b, Expr b)] -> [(b, Expr b)] -> [(b, Expr b)] forall a. [a] -> [a] -> [a] ++ [Bind b] -> [(b, Expr b)] forall b. [Bind b] -> [(b, Expr b)] flattenBinds [Bind b] binds flattenBinds [] = [] -- | We often want to strip off leading lambdas before getting down to -- business. Variants are 'collectTyBinders', 'collectValBinders', -- and 'collectTyAndValBinders' collectBinders :: Expr b -> ([b], Expr b) collectTyBinders :: CoreExpr -> ([TyVar], CoreExpr) collectValBinders :: CoreExpr -> ([Id], CoreExpr) collectTyAndValBinders :: CoreExpr -> ([TyVar], [Id], CoreExpr) -- | Strip off exactly N leading lambdas (type or value). -- Good for use with join points. -- Panic if there aren't enough collectNBinders :: JoinArity -> Expr b -> ([b], Expr b) collectBinders :: forall b. Expr b -> ([b], Expr b) collectBinders Expr b expr = [b] -> Expr b -> ([b], Expr b) forall {a}. [a] -> Expr a -> ([a], Expr a) go [] Expr b expr where go :: [a] -> Expr a -> ([a], Expr a) go [a] bs (Lam a b Expr a e) = [a] -> Expr a -> ([a], Expr a) go (a ba -> [a] -> [a] forall a. a -> [a] -> [a] :[a] bs) Expr a e go [a] bs Expr a e = ([a] -> [a] forall a. [a] -> [a] reverse [a] bs, Expr a e) collectTyBinders :: CoreExpr -> ([Id], CoreExpr) collectTyBinders CoreExpr expr = [Id] -> CoreExpr -> ([Id], CoreExpr) go [] CoreExpr expr where go :: [Id] -> CoreExpr -> ([Id], CoreExpr) go [Id] tvs (Lam Id b CoreExpr e) | Id -> Bool isTyVar Id b = [Id] -> CoreExpr -> ([Id], CoreExpr) go (Id bId -> [Id] -> [Id] forall a. a -> [a] -> [a] :[Id] tvs) CoreExpr e go [Id] tvs CoreExpr e = ([Id] -> [Id] forall a. [a] -> [a] reverse [Id] tvs, CoreExpr e) collectValBinders :: CoreExpr -> ([Id], CoreExpr) collectValBinders CoreExpr expr = [Id] -> CoreExpr -> ([Id], CoreExpr) go [] CoreExpr expr where go :: [Id] -> CoreExpr -> ([Id], CoreExpr) go [Id] ids (Lam Id b CoreExpr e) | Id -> Bool isId Id b = [Id] -> CoreExpr -> ([Id], CoreExpr) go (Id bId -> [Id] -> [Id] forall a. a -> [a] -> [a] :[Id] ids) CoreExpr e go [Id] ids CoreExpr body = ([Id] -> [Id] forall a. [a] -> [a] reverse [Id] ids, CoreExpr body) collectTyAndValBinders :: CoreExpr -> ([Id], [Id], CoreExpr) collectTyAndValBinders CoreExpr expr = ([Id] tvs, [Id] ids, CoreExpr body) where ([Id] tvs, CoreExpr body1) = CoreExpr -> ([Id], CoreExpr) collectTyBinders CoreExpr expr ([Id] ids, CoreExpr body) = CoreExpr -> ([Id], CoreExpr) collectValBinders CoreExpr body1 collectNBinders :: forall b. Arity -> Expr b -> ([b], Expr b) collectNBinders Arity orig_n Expr b orig_expr = Arity -> [b] -> Expr b -> ([b], Expr b) go Arity orig_n [] Expr b orig_expr where go :: Arity -> [b] -> Expr b -> ([b], Expr b) go Arity 0 [b] bs Expr b expr = ([b] -> [b] forall a. [a] -> [a] reverse [b] bs, Expr b expr) go Arity n [b] bs (Lam b b Expr b e) = Arity -> [b] -> Expr b -> ([b], Expr b) go (Arity nArity -> Arity -> Arity forall a. Num a => a -> a -> a -Arity 1) (b bb -> [b] -> [b] forall a. a -> [a] -> [a] :[b] bs) Expr b e go Arity _ [b] _ Expr b _ = String -> SDoc -> ([b], Expr b) forall a. HasCallStack => String -> SDoc -> a pprPanic String "collectNBinders" (SDoc -> ([b], Expr b)) -> SDoc -> ([b], Expr b) forall a b. (a -> b) -> a -> b $ Arity -> SDoc forall doc. IsLine doc => Arity -> doc int Arity orig_n -- | Strip off exactly N leading value lambdas -- returning all the binders found up to that point -- Return Nothing if there aren't enough collectNValBinders_maybe :: Arity -> CoreExpr -> Maybe ([Var], CoreExpr) collectNValBinders_maybe :: Arity -> CoreExpr -> Maybe ([Id], CoreExpr) collectNValBinders_maybe Arity orig_n CoreExpr orig_expr = Arity -> [Id] -> CoreExpr -> Maybe ([Id], CoreExpr) forall {t}. (Eq t, Num t) => t -> [Id] -> CoreExpr -> Maybe ([Id], CoreExpr) go Arity orig_n [] CoreExpr orig_expr where go :: t -> [Id] -> CoreExpr -> Maybe ([Id], CoreExpr) go t 0 [Id] bs CoreExpr expr = ([Id], CoreExpr) -> Maybe ([Id], CoreExpr) forall a. a -> Maybe a Just ([Id] -> [Id] forall a. [a] -> [a] reverse [Id] bs, CoreExpr expr) go t n [Id] bs (Lam Id b CoreExpr e) | Id -> Bool isId Id b = t -> [Id] -> CoreExpr -> Maybe ([Id], CoreExpr) go (t nt -> t -> t forall a. Num a => a -> a -> a -t 1) (Id bId -> [Id] -> [Id] forall a. a -> [a] -> [a] :[Id] bs) CoreExpr e | Bool otherwise = t -> [Id] -> CoreExpr -> Maybe ([Id], CoreExpr) go t n (Id bId -> [Id] -> [Id] forall a. a -> [a] -> [a] :[Id] bs) CoreExpr e go t _ [Id] _ CoreExpr _ = Maybe ([Id], CoreExpr) forall a. Maybe a Nothing -- | Takes a nested application expression and returns the function -- being applied and the arguments to which it is applied collectArgs :: Expr b -> (Expr b, [Arg b]) collectArgs :: forall b. Expr b -> (Expr b, [Expr b]) collectArgs Expr b expr = Expr b -> [Expr b] -> (Expr b, [Expr b]) forall {b}. Expr b -> [Expr b] -> (Expr b, [Expr b]) go Expr b expr [] where go :: Expr b -> [Expr b] -> (Expr b, [Expr b]) go (App Expr b f Expr b a) [Expr b] as = Expr b -> [Expr b] -> (Expr b, [Expr b]) go Expr b f (Expr b aExpr b -> [Expr b] -> [Expr b] forall a. a -> [a] -> [a] :[Expr b] as) go Expr b e [Expr b] as = (Expr b e, [Expr b] as) -- | Takes a nested application expression and returns the function -- being applied. Looking through casts and ticks to find it. collectFunSimple :: Expr b -> Expr b collectFunSimple :: forall b. Expr b -> Expr b collectFunSimple Expr b expr = Expr b -> Expr b forall b. Expr b -> Expr b go Expr b expr where go :: Expr b -> Expr b go Expr b expr' = case Expr b expr' of App Expr b f Expr b _a -> Expr b -> Expr b go Expr b f Tick CoreTickish _t Expr b e -> Expr b -> Expr b go Expr b e Cast Expr b e CoercionR _co -> Expr b -> Expr b go Expr b e Expr b e -> Expr b e -- | fmap on the body of a lambda. -- wrapLamBody f (\x -> body) == (\x -> f body) wrapLamBody :: (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr wrapLamBody :: (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr wrapLamBody CoreExpr -> CoreExpr f CoreExpr expr = CoreExpr -> CoreExpr go CoreExpr expr where go :: CoreExpr -> CoreExpr go (Lam Id v CoreExpr body) = Id -> CoreExpr -> CoreExpr forall b. b -> Expr b -> Expr b Lam Id v (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr forall a b. (a -> b) -> a -> b $ CoreExpr -> CoreExpr go CoreExpr body go CoreExpr expr = CoreExpr -> CoreExpr f CoreExpr expr -- | Attempt to remove the last N arguments of a function call. -- Strip off any ticks or coercions encountered along the way and any -- at the end. stripNArgs :: Word -> Expr a -> Maybe (Expr a) stripNArgs :: forall a. Word -> Expr a -> Maybe (Expr a) stripNArgs !Word n (Tick CoreTickish _ Expr a e) = Word -> Expr a -> Maybe (Expr a) forall a. Word -> Expr a -> Maybe (Expr a) stripNArgs Word n Expr a e stripNArgs Word n (Cast Expr a f CoercionR _) = Word -> Expr a -> Maybe (Expr a) forall a. Word -> Expr a -> Maybe (Expr a) stripNArgs Word n Expr a f stripNArgs Word 0 Expr a e = Expr a -> Maybe (Expr a) forall a. a -> Maybe a Just Expr a e stripNArgs Word n (App Expr a f Expr a _) = Word -> Expr a -> Maybe (Expr a) forall a. Word -> Expr a -> Maybe (Expr a) stripNArgs (Word n Word -> Word -> Word forall a. Num a => a -> a -> a - Word 1) Expr a f stripNArgs Word _ Expr a _ = Maybe (Expr a) forall a. Maybe a Nothing -- | Like @collectArgs@, but also collects looks through floatable -- ticks if it means that we can find more arguments. collectArgsTicks :: (CoreTickish -> Bool) -> Expr b -> (Expr b, [Arg b], [CoreTickish]) collectArgsTicks :: forall b. (CoreTickish -> Bool) -> Expr b -> (Expr b, [Expr b], [CoreTickish]) collectArgsTicks CoreTickish -> Bool skipTick Expr b expr = Expr b -> [Expr b] -> [CoreTickish] -> (Expr b, [Expr b], [CoreTickish]) go Expr b expr [] [] where go :: Expr b -> [Expr b] -> [CoreTickish] -> (Expr b, [Expr b], [CoreTickish]) go (App Expr b f Expr b a) [Expr b] as [CoreTickish] ts = Expr b -> [Expr b] -> [CoreTickish] -> (Expr b, [Expr b], [CoreTickish]) go Expr b f (Expr b aExpr b -> [Expr b] -> [Expr b] forall a. a -> [a] -> [a] :[Expr b] as) [CoreTickish] ts go (Tick CoreTickish t Expr b e) [Expr b] as [CoreTickish] ts | CoreTickish -> Bool skipTick CoreTickish t = Expr b -> [Expr b] -> [CoreTickish] -> (Expr b, [Expr b], [CoreTickish]) go Expr b e [Expr b] as (CoreTickish tCoreTickish -> [CoreTickish] -> [CoreTickish] forall a. a -> [a] -> [a] :[CoreTickish] ts) go Expr b e [Expr b] as [CoreTickish] ts = (Expr b e, [Expr b] as, [CoreTickish] -> [CoreTickish] forall a. [a] -> [a] reverse [CoreTickish] ts) {- ************************************************************************ * * \subsection{Predicates} * * ************************************************************************ At one time we optionally carried type arguments through to runtime. @isRuntimeVar v@ returns if (Lam v _) really becomes a lambda at runtime, i.e. if type applications are actual lambdas because types are kept around at runtime. Similarly isRuntimeArg. -} -- | Will this variable exist at runtime? isRuntimeVar :: Var -> Bool isRuntimeVar :: Id -> Bool isRuntimeVar = Id -> Bool isId -- | Will this argument expression exist at runtime? isRuntimeArg :: CoreExpr -> Bool isRuntimeArg :: CoreExpr -> Bool isRuntimeArg = CoreExpr -> Bool forall b. Expr b -> Bool isValArg -- | Returns @True@ for value arguments, false for type args -- NB: coercions are value arguments (zero width, to be sure, -- like State#, but still value args). isValArg :: Expr b -> Bool isValArg :: forall b. Expr b -> Bool isValArg Expr b e = Bool -> Bool not (Expr b -> Bool forall b. Expr b -> Bool isTypeArg Expr b e) -- | Returns @True@ iff the expression is a 'Type' or 'Coercion' -- expression at its top level isTyCoArg :: Expr b -> Bool isTyCoArg :: forall b. Expr b -> Bool isTyCoArg (Type {}) = Bool True isTyCoArg (Coercion {}) = Bool True isTyCoArg Expr b _ = Bool False -- | Returns @True@ iff the expression is a 'Coercion' -- expression at its top level isCoArg :: Expr b -> Bool isCoArg :: forall b. Expr b -> Bool isCoArg (Coercion {}) = Bool True isCoArg Expr b _ = Bool False -- | Returns @True@ iff the expression is a 'Type' expression at its -- top level. Note this does NOT include 'Coercion's. isTypeArg :: Expr b -> Bool isTypeArg :: forall b. Expr b -> Bool isTypeArg (Type {}) = Bool True isTypeArg Expr b _ = Bool False -- | The number of binders that bind values rather than types valBndrCount :: [CoreBndr] -> Int valBndrCount :: [Id] -> Arity valBndrCount = (Id -> Bool) -> [Id] -> Arity forall a. (a -> Bool) -> [a] -> Arity count Id -> Bool isId -- | The number of argument expressions that are values rather than types at their top level valArgCount :: [Arg b] -> Int valArgCount :: forall b. [Arg b] -> Arity valArgCount = (Arg b -> Bool) -> [Arg b] -> Arity forall a. (a -> Bool) -> [a] -> Arity count Arg b -> Bool forall b. Expr b -> Bool isValArg {- ************************************************************************ * * \subsection{Annotated core} * * ************************************************************************ -} -- | Annotated core: allows annotation at every node in the tree type AnnExpr bndr annot = (annot, AnnExpr' bndr annot) -- | A clone of the 'Expr' type but allowing annotation at every tree node data AnnExpr' bndr annot = AnnVar Id | AnnLit Literal | AnnLam bndr (AnnExpr bndr annot) | AnnApp (AnnExpr bndr annot) (AnnExpr bndr annot) | AnnCase (AnnExpr bndr annot) bndr Type [AnnAlt bndr annot] | AnnLet (AnnBind bndr annot) (AnnExpr bndr annot) | AnnCast (AnnExpr bndr annot) (annot, Coercion) -- Put an annotation on the (root of) the coercion | AnnTick CoreTickish (AnnExpr bndr annot) | AnnType Type | AnnCoercion Coercion -- | A clone of the 'Alt' type but allowing annotation at every tree node data AnnAlt bndr annot = AnnAlt AltCon [bndr] (AnnExpr bndr annot) -- | A clone of the 'Bind' type but allowing annotation at every tree node data AnnBind bndr annot = AnnNonRec bndr (AnnExpr bndr annot) | AnnRec [(bndr, AnnExpr bndr annot)] -- | Takes a nested application expression and returns the function -- being applied and the arguments to which it is applied collectAnnArgs :: AnnExpr b a -> (AnnExpr b a, [AnnExpr b a]) collectAnnArgs :: forall b a. AnnExpr b a -> (AnnExpr b a, [AnnExpr b a]) collectAnnArgs AnnExpr b a expr = AnnExpr b a -> [AnnExpr b a] -> (AnnExpr b a, [AnnExpr b a]) forall {bndr} {annot}. AnnExpr bndr annot -> [AnnExpr bndr annot] -> (AnnExpr bndr annot, [AnnExpr bndr annot]) go AnnExpr b a expr [] where go :: AnnExpr bndr annot -> [AnnExpr bndr annot] -> (AnnExpr bndr annot, [AnnExpr bndr annot]) go (annot _, AnnApp AnnExpr bndr annot f AnnExpr bndr annot a) [AnnExpr bndr annot] as = AnnExpr bndr annot -> [AnnExpr bndr annot] -> (AnnExpr bndr annot, [AnnExpr bndr annot]) go AnnExpr bndr annot f (AnnExpr bndr annot aAnnExpr bndr annot -> [AnnExpr bndr annot] -> [AnnExpr bndr annot] forall a. a -> [a] -> [a] :[AnnExpr bndr annot] as) go AnnExpr bndr annot e [AnnExpr bndr annot] as = (AnnExpr bndr annot e, [AnnExpr bndr annot] as) collectAnnArgsTicks :: (CoreTickish -> Bool) -> AnnExpr b a -> (AnnExpr b a, [AnnExpr b a], [CoreTickish]) collectAnnArgsTicks :: forall b a. (CoreTickish -> Bool) -> AnnExpr b a -> (AnnExpr b a, [AnnExpr b a], [CoreTickish]) collectAnnArgsTicks CoreTickish -> Bool tickishOk AnnExpr b a expr = AnnExpr b a -> [AnnExpr b a] -> [CoreTickish] -> (AnnExpr b a, [AnnExpr b a], [CoreTickish]) go AnnExpr b a expr [] [] where go :: AnnExpr b a -> [AnnExpr b a] -> [CoreTickish] -> (AnnExpr b a, [AnnExpr b a], [CoreTickish]) go (a _, AnnApp AnnExpr b a f AnnExpr b a a) [AnnExpr b a] as [CoreTickish] ts = AnnExpr b a -> [AnnExpr b a] -> [CoreTickish] -> (AnnExpr b a, [AnnExpr b a], [CoreTickish]) go AnnExpr b a f (AnnExpr b a aAnnExpr b a -> [AnnExpr b a] -> [AnnExpr b a] forall a. a -> [a] -> [a] :[AnnExpr b a] as) [CoreTickish] ts go (a _, AnnTick CoreTickish t AnnExpr b a e) [AnnExpr b a] as [CoreTickish] ts | CoreTickish -> Bool tickishOk CoreTickish t = AnnExpr b a -> [AnnExpr b a] -> [CoreTickish] -> (AnnExpr b a, [AnnExpr b a], [CoreTickish]) go AnnExpr b a e [AnnExpr b a] as (CoreTickish tCoreTickish -> [CoreTickish] -> [CoreTickish] forall a. a -> [a] -> [a] :[CoreTickish] ts) go AnnExpr b a e [AnnExpr b a] as [CoreTickish] ts = (AnnExpr b a e, [AnnExpr b a] as, [CoreTickish] -> [CoreTickish] forall a. [a] -> [a] reverse [CoreTickish] ts) deAnnotate :: AnnExpr bndr annot -> Expr bndr deAnnotate :: forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate (annot _, AnnExpr' bndr annot e) = AnnExpr' bndr annot -> Expr bndr forall bndr annot. AnnExpr' bndr annot -> Expr bndr deAnnotate' AnnExpr' bndr annot e deAnnotate' :: AnnExpr' bndr annot -> Expr bndr deAnnotate' :: forall bndr annot. AnnExpr' bndr annot -> Expr bndr deAnnotate' (AnnType Type t) = Type -> Expr bndr forall b. Type -> Expr b Type Type t deAnnotate' (AnnCoercion CoercionR co) = CoercionR -> Expr bndr forall b. CoercionR -> Expr b Coercion CoercionR co deAnnotate' (AnnVar Id v) = Id -> Expr bndr forall b. Id -> Expr b Var Id v deAnnotate' (AnnLit Literal lit) = Literal -> Expr bndr forall b. Literal -> Expr b Lit Literal lit deAnnotate' (AnnLam bndr binder AnnExpr bndr annot body) = bndr -> Expr bndr -> Expr bndr forall b. b -> Expr b -> Expr b Lam bndr binder (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot body) deAnnotate' (AnnApp AnnExpr bndr annot fun AnnExpr bndr annot arg) = Expr bndr -> Expr bndr -> Expr bndr forall b. Expr b -> Expr b -> Expr b App (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot fun) (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot arg) deAnnotate' (AnnCast AnnExpr bndr annot e (annot _,CoercionR co)) = Expr bndr -> CoercionR -> Expr bndr forall b. Expr b -> CoercionR -> Expr b Cast (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot e) CoercionR co deAnnotate' (AnnTick CoreTickish tick AnnExpr bndr annot body) = CoreTickish -> Expr bndr -> Expr bndr forall b. CoreTickish -> Expr b -> Expr b Tick CoreTickish tick (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot body) deAnnotate' (AnnLet AnnBind bndr annot bind AnnExpr bndr annot body) = Bind bndr -> Expr bndr -> Expr bndr forall b. Bind b -> Expr b -> Expr b Let (AnnBind bndr annot -> Bind bndr forall b annot. AnnBind b annot -> Bind b deAnnBind AnnBind bndr annot bind) (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot body) deAnnotate' (AnnCase AnnExpr bndr annot scrut bndr v Type t [AnnAlt bndr annot] alts) = Expr bndr -> bndr -> Type -> [Alt bndr] -> Expr bndr forall b. Expr b -> b -> Type -> [Alt b] -> Expr b Case (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot scrut) bndr v Type t ((AnnAlt bndr annot -> Alt bndr) -> [AnnAlt bndr annot] -> [Alt bndr] forall a b. (a -> b) -> [a] -> [b] map AnnAlt bndr annot -> Alt bndr forall bndr annot. AnnAlt bndr annot -> Alt bndr deAnnAlt [AnnAlt bndr annot] alts) deAnnAlt :: AnnAlt bndr annot -> Alt bndr deAnnAlt :: forall bndr annot. AnnAlt bndr annot -> Alt bndr deAnnAlt (AnnAlt AltCon con [bndr] args AnnExpr bndr annot rhs) = AltCon -> [bndr] -> Expr bndr -> Alt bndr forall b. AltCon -> [b] -> Expr b -> Alt b Alt AltCon con [bndr] args (AnnExpr bndr annot -> Expr bndr forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr bndr annot rhs) deAnnBind :: AnnBind b annot -> Bind b deAnnBind :: forall b annot. AnnBind b annot -> Bind b deAnnBind (AnnNonRec b var AnnExpr b annot rhs) = b -> Expr b -> Bind b forall b. b -> Expr b -> Bind b NonRec b var (AnnExpr b annot -> Expr b forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr b annot rhs) deAnnBind (AnnRec [(b, AnnExpr b annot)] pairs) = [(b, Expr b)] -> Bind b forall b. [(b, Expr b)] -> Bind b Rec [(b v,AnnExpr b annot -> Expr b forall bndr annot. AnnExpr bndr annot -> Expr bndr deAnnotate AnnExpr b annot rhs) | (b v,AnnExpr b annot rhs) <- [(b, AnnExpr b annot)] pairs] -- | As 'collectBinders' but for 'AnnExpr' rather than 'Expr' collectAnnBndrs :: AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) collectAnnBndrs :: forall bndr annot. AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) collectAnnBndrs AnnExpr bndr annot e = [bndr] -> AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) forall {a} {annot}. [a] -> AnnExpr a annot -> ([a], AnnExpr a annot) collect [] AnnExpr bndr annot e where collect :: [a] -> AnnExpr a annot -> ([a], AnnExpr a annot) collect [a] bs (annot _, AnnLam a b AnnExpr a annot body) = [a] -> AnnExpr a annot -> ([a], AnnExpr a annot) collect (a ba -> [a] -> [a] forall a. a -> [a] -> [a] :[a] bs) AnnExpr a annot body collect [a] bs AnnExpr a annot body = ([a] -> [a] forall a. [a] -> [a] reverse [a] bs, AnnExpr a annot body) -- | As 'collectNBinders' but for 'AnnExpr' rather than 'Expr' collectNAnnBndrs :: Int -> AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) collectNAnnBndrs :: forall bndr annot. Arity -> AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) collectNAnnBndrs Arity orig_n AnnExpr bndr annot e = Arity -> [bndr] -> AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) collect Arity orig_n [] AnnExpr bndr annot e where collect :: Arity -> [bndr] -> AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) collect Arity 0 [bndr] bs AnnExpr bndr annot body = ([bndr] -> [bndr] forall a. [a] -> [a] reverse [bndr] bs, AnnExpr bndr annot body) collect Arity n [bndr] bs (annot _, AnnLam bndr b AnnExpr bndr annot body) = Arity -> [bndr] -> AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot) collect (Arity nArity -> Arity -> Arity forall a. Num a => a -> a -> a -Arity 1) (bndr bbndr -> [bndr] -> [bndr] forall a. a -> [a] -> [a] :[bndr] bs) AnnExpr bndr annot body collect Arity _ [bndr] _ AnnExpr bndr annot _ = String -> SDoc -> ([bndr], AnnExpr bndr annot) forall a. HasCallStack => String -> SDoc -> a pprPanic String "collectNBinders" (SDoc -> ([bndr], AnnExpr bndr annot)) -> SDoc -> ([bndr], AnnExpr bndr annot) forall a b. (a -> b) -> a -> b $ Arity -> SDoc forall doc. IsLine doc => Arity -> doc int Arity orig_n