CoreSyn.lhs 53.1 KB
Newer Older
1
%
Simon Marlow's avatar
Simon Marlow committed
2
% (c) The University of Glasgow 2006
3
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4
%
Simon Marlow's avatar
Simon Marlow committed
5

6
\begin{code}
7
{-# LANGUAGE DeriveDataTypeable, DeriveFunctor #-}
8

Ian Lynagh's avatar
Ian Lynagh committed
9 10 11 12 13 14 15
{-# OPTIONS -fno-warn-tabs #-}
-- The above warning supression flag is a temporary kludge.
-- While working on this module you are encouraged to remove it and
-- detab the module (please do the detabbing in a separate patch). See
--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#TabsvsSpaces
-- for details

16
-- | CoreSyn holds all the main data types for use by for the Glasgow Haskell Compiler midsection
17
module CoreSyn (
18
	-- * Main data types
19 20 21
        Expr(..), Alt, Bind(..), AltCon(..), Arg, Tickish(..),
        CoreProgram, CoreExpr, CoreAlt, CoreBind, CoreArg, CoreBndr,
        TaggedExpr, TaggedAlt, TaggedBind, TaggedArg, TaggedBndr(..),
22

23 24
        -- ** 'Expr' construction
	mkLets, mkLams,
25
	mkApps, mkTyApps, mkCoApps, mkVarApps,
26 27 28
	
	mkIntLit, mkIntLitInt,
	mkWordLit, mkWordLitWord,
29
	mkWord64LitWord64, mkInt64LitInt64,
30 31 32 33
	mkCharLit, mkStringLit,
	mkFloatLit, mkFloatLitFloat,
	mkDoubleLit, mkDoubleLitDouble,
	
34
	mkConApp, mkTyBind, mkCoBind,
35
	varToCoreExpr, varsToCoreExprs,
36

37
        isId, cmpAltCon, cmpAlt, ltAlt,
38 39
	
	-- ** Simple 'Expr' access functions and predicates
40
	bindersOf, bindersOfBinds, rhssOfBind, rhssOfAlts, 
41
	collectBinders, collectTyBinders, collectValBinders, collectTyAndValBinders,
Simon Marlow's avatar
Simon Marlow committed
42
        collectArgs, flattenBinds,
43

44 45
        isValArg, isTypeArg, isTyCoArg, valArgCount, valBndrCount,
        isRuntimeArg, isRuntimeVar,
46

47 48 49 50
        tickishCounts, tickishScoped, tickishIsCode, mkNoTick, mkNoScope,
        tickishCanSplit,

        -- * Unfolding data types
51
        Unfolding(..),  UnfoldingGuidance(..), UnfoldingSource(..),
52
        DFunArg(..), dfunArgExprs,
53

54
	-- ** Constructing 'Unfolding's
55
	noUnfolding, evaldUnfolding, mkOtherCon,
56
        unSaturatedOk, needSaturated, boringCxtOk, boringCxtNotOk,
57 58
	
	-- ** Predicates and deconstruction on 'Unfolding'
59
	unfoldingTemplate, setUnfoldingTemplate, expandUnfolding_maybe,
60
	maybeUnfoldingTemplate, otherCons, unfoldingArity,
61
	isValueUnfolding, isEvaldUnfolding, isCheapUnfolding,
62
        isExpandableUnfolding, isConLikeUnfolding, isCompulsoryUnfolding,
63
        isStableUnfolding, isStableCoreUnfolding_maybe,
64 65
        isClosedUnfolding, hasSomeUnfolding, 
	canUnfold, neverUnfoldGuidance, isStableSource,
66

67
	-- * Strictness
68
	seqExpr, seqExprs, seqUnfolding, 
69

70 71 72
	-- * Annotated expression data types
	AnnExpr, AnnExpr'(..), AnnBind(..), AnnAlt,
	
Simon Marlow's avatar
Simon Marlow committed
73 74 75
        -- ** Operations on annotated expressions
        collectAnnArgs,

76
	-- ** Operations on annotations
77
	deAnnotate, deAnnotate', deAnnAlt, collectAnnBndrs,
78

79
	-- * Core rule data types
80
	CoreRule(..),	-- CoreSubst, CoreTidy, CoreFVs, PprCore only
81
	RuleName, IdUnfoldingFun,
82 83
	
	-- ** Operations on 'CoreRule's 
84
	seqRules, ruleArity, ruleName, ruleIdName, ruleActivation,
85
	setRuleIdName,
86 87 88 89
	isBuiltinRule, isLocalRule,

	-- * Core vectorisation declarations data type
	CoreVect(..)
90 91
    ) where

92
#include "HsVersions.h"
93

Simon Marlow's avatar
Simon Marlow committed
94 95 96 97 98 99 100
import CostCentre
import Var
import Type
import Coercion
import Name
import Literal
import DataCon
101
import Module
102
import TyCon
Simon Marlow's avatar
Simon Marlow committed
103
import BasicTypes
104
import FastString
105
import Outputable
twanvl's avatar
twanvl committed
106
import Util
107

108
import Data.Data hiding (TyCon)
109
import Data.Int
110 111
import Data.Word

112
infixl 4 `mkApps`, `mkTyApps`, `mkVarApps`, `App`, `mkCoApps`
113
-- Left associative, so that we can say (f `mkTyApps` xs `mkVarApps` ys)
114 115 116 117
\end{code}

%************************************************************************
%*									*
118
\subsection{The main data types}
119 120 121
%*									*
%************************************************************************

122
These data types are the heart of the compiler
123

124
\begin{code}
125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157
-- | This is the data type that represents GHCs core intermediate language. Currently
-- GHC uses System FC <http://research.microsoft.com/~simonpj/papers/ext-f/> 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 'HsExpr.HsExpr' with the names being 'RdrName.RdrNames'
--
-- 2. This syntax tree is /renamed/, which attaches a 'Unique.Unique' to every 'RdrName.RdrName'
--    (yielding a '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)
-- @
--
-- 3. The resulting syntax tree undergoes type checking (which also deals with instantiating
--    type class arguments) to yield a 'HsExpr.HsExpr' type that has 'Id.Id' as it's names.
--
-- 4. Finally the syntax tree is /desugared/ from the expressive 'HsExpr.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.
batterseapower's avatar
batterseapower committed
158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224
--
-- The language consists of the following elements:
--
-- *  Variables
--
-- *  Primitive literals
--
-- *  Applications: note that the argument may be a 'Type'.
--
--    See "CoreSyn#let_app_invariant" for another invariant
--
-- *  Lambda abstraction
--
-- *  Recursive and non recursive @let@s. Operationally
--    this corresponds to allocating a thunk for the things
--    bound and then executing the sub-expression.
--    
--    #top_level_invariant#
--    #letrec_invariant#
--    
--    The right hand sides of all top-level and recursive @let@s
--    /must/ be of lifted type (see "Type#type_classification" for
--    the meaning of /lifted/ vs. /unlifted/).
--    
--    #let_app_invariant#
--    The right hand side of of a non-recursive 'Let' 
--    _and_ the argument of an 'App',
--    /may/ be of unlifted type, but only if the expression 
--    is ok-for-speculation.  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
--    'CoreUtils.needsCaseBinding' can help you determine which to generate, or
--    alternatively use 'MkCore.mkCoreLet' rather than this constructor directly,
--    which will generate a @case@ if necessary
--    
--    #type_let#
--    We allow a /non-recursive/ let to bind a type variable, thus:
--    
--    > Let (NonRec tv (Type ty)) body
--    
--    This can be very convenient for postponing type substitutions until
--    the next run of the simplifier.
--    
--    At the moment, the rest of the compiler only deals with type-let
--    in a Let expression, rather than at top level.  We may want to revist
--    this choice.
--
-- *  Case split. 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
--    
--    #case_invariants#
--    This is one of the more complicated elements of the Core language, 
--    and comes with a number of restrictions:
--    
225 226
--    1. The list of alternatives may be empty; 
--       See Note [Empty case alternatives]
Simon Peyton Jones's avatar
Simon Peyton Jones committed
227 228 229
--
--    2. The 'DEFAULT' case alternative must be first in the list, 
--       if it occurs at all.
batterseapower's avatar
batterseapower committed
230
--    
Simon Peyton Jones's avatar
Simon Peyton Jones committed
231
--    3. The remaining cases are in order of increasing 
batterseapower's avatar
batterseapower committed
232 233
--         tag	(for 'DataAlts') or
--         lit	(for 'LitAlts').
Simon Peyton Jones's avatar
Simon Peyton Jones committed
234 235
--       This makes finding the relevant constructor easy, 
--       and makes comparison easier too.
batterseapower's avatar
batterseapower committed
236
--    
Simon Peyton Jones's avatar
Simon Peyton Jones committed
237 238
--    4. The list of alternatives must be exhaustive. An /exhaustive/ case 
--       does not necessarily mention all constructors:
batterseapower's avatar
batterseapower committed
239
--    
Simon Peyton Jones's avatar
Simon Peyton Jones committed
240 241 242 243 244 245 246 247
--    	 @
--    	      data Foo = Red | Green | Blue
--    	 ... case x of 
--    	      Red   -> True
--    	      other -> f (case x of 
--    	                      Green -> ...
--    	                      Blue  -> ... ) ...
--    	 @
batterseapower's avatar
batterseapower committed
248
--    
Simon Peyton Jones's avatar
Simon Peyton Jones committed
249 250
--    	 The inner case does not need a @Red@ alternative, because @x@ 
--    	 can't be @Red@ at that program point.
batterseapower's avatar
batterseapower committed
251 252 253 254 255 256 257 258 259 260 261
--
-- *  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.
--
-- *  Notes. These allow general information to be added to expressions
--    in the syntax tree
--
-- *  A type: this should only show up at the top level of an Arg
--
-- *  A coercion
262
data Expr b
batterseapower's avatar
batterseapower committed
263 264 265 266 267
  = Var	  Id
  | Lit   Literal
  | App   (Expr b) (Arg b)
  | Lam   b (Expr b)
  | Let   (Bind b) (Expr b)
Simon Peyton Jones's avatar
Simon Peyton Jones committed
268
  | Case  (Expr b) b Type [Alt b]	-- See #case_invariant#
batterseapower's avatar
batterseapower committed
269
  | Cast  (Expr b) Coercion
270
  | Tick  (Tickish Id) (Expr b)
batterseapower's avatar
batterseapower committed
271 272
  | Type  Type
  | Coercion Coercion
273
  deriving (Data, Typeable)
274 275 276 277 278 279 280 281 282 283 284

-- | 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)@
type Alt b = (AltCon, [b], Expr b)

-- | A case alternative constructor (i.e. pattern match)
285 286 287 288 289 290 291 292 293 294
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 (Eq, Ord, Data, Typeable)
295

296
-- | Binding, used for top level bindings in a module and local bindings in a @let@.
297
data Bind b = NonRec b (Expr b)
298
	    | Rec [(b, (Expr b))]
299
  deriving (Data, Typeable)
300 301
\end{code}

302 303 304 305 306 307 308 309 310 311 312 313 314 315 316
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 Trac #5603) if you say
    case 3 of
      S# x -> ...
      J# _ _ -> ...
(where S#, J# 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.


317 318 319 320
-------------------------- CoreSyn INVARIANTS ---------------------------

Note [CoreSyn top-level invariant]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
321
See #toplevel_invariant#
322 323 324

Note [CoreSyn letrec invariant]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
325
See #letrec_invariant#
326 327 328

Note [CoreSyn let/app invariant]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
329 330 331
See #let_app_invariant#

This is intially enforced by DsUtils.mkCoreLet and mkCoreApp
332 333 334

Note [CoreSyn case invariants]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
335
See #case_invariants#
336 337

Note [CoreSyn let goal]
338
~~~~~~~~~~~~~~~~~~~~~~~
339 340 341 342
* 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.

343 344
Note [Type let]
~~~~~~~~~~~~~~~
345
See #type_let#
346

347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395
Note [Empty case alternatives]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The alternatives of a case expression should be exhaustive.  A case expression
can have empty alternatives if (and only if) the scrutinee is bound to raise
an exception or diverge.  So:
   Case (error Int "Hello") b Bool []
is fine, and has type Bool.  This 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!  I'll write this
   case (error Int "Hello") of Bool {}
with the return type just before the alterantives.

Here's another example:
  data T
  f :: T -> Bool
  f = \(x:t). case x of Bool {}
Since T has no data constructors, the case alterantives are of course
empty.  However note that 'x' is not bound to a visbily-bottom value;
it's the *type* that tells us it's going to diverge.  Its a bit of a
degnerate situation but we do NOT want to replace
   case x of Bool {}   -->   error Bool "Inaccessible case"
because x might raise an exception, and *that*'s what we want to see!
(Trac #6067 is an example.) To preserve semantics we'd have to say
   x `seq` error Bool "Inaccessible case"   
 but the 'seq' is just a case, so we are back to square 1.  Or I suppose
we could say
   x |> UnsafeCoerce T Bool
but that loses all trace of the fact that this originated with an empty
set of alternatives.

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.


Simon Peyton Jones's avatar
Simon Peyton Jones committed
396 397 398 399 400 401
%************************************************************************
%*									*
              Ticks
%*									*
%************************************************************************

402
\begin{code}
403 404 405 406 407 408 409 410 411 412 413
-- | Allows attaching extra information to points in expressions
data Tickish id =
    -- | An @{-# SCC #-}@ profiling annotation, either automatically
    -- added by the desugarer as a result of -auto-all, or added by
    -- the user.
    ProfNote {
      profNoteCC    :: CostCentre, -- ^ the cost centre
      profNoteCount :: !Bool,      -- ^ bump the entry count?
      profNoteScope :: !Bool       -- ^ scopes over the enclosed expression
                                   -- (i.e. not just a tick)
    }
414

415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481
  -- | A "tick" used by HPC to track the execution of each
  -- subexpression in the original source code.
  | HpcTick {
      tickModule :: Module,
      tickId     :: !Int
    }

  -- | A breakpoint for the GHCi debugger.  This behaves like an HPC
  -- tick, but has a list of free variables which will be available
  -- for inspection in GHCi when the program stops at the breakpoint.
  --
  -- NB. we must take account of these Ids when (a) counting free variables,
  -- and (b) substituting (don't substitute for them)
  | Breakpoint
    { breakpointId     :: !Int
    , breakpointFVs    :: [id]  -- ^ the order of this list is important:
                                -- it matches the order of the lists in the
                                -- appropriate entry in HscTypes.ModBreaks.
                                --
                                -- Careful about substitution!  See
                                -- Note [substTickish] in CoreSubst.
    }

  deriving (Eq, Ord, Data, Typeable)


-- | A "tick" note is one that counts evaluations in some way.  We
-- cannot discard a tick, and the compiler should preserve the number
-- of ticks as far as possible.
--
-- Hwever, we stil allow the simplifier to increase or decrease
-- sharing, so in practice the actual number of ticks may vary, except
-- that we never change the value from zero to non-zero or vice versa.
--
tickishCounts :: Tickish id -> Bool
tickishCounts n@ProfNote{} = profNoteCount n
tickishCounts HpcTick{}    = True
tickishCounts Breakpoint{} = True

tickishScoped :: Tickish id -> Bool
tickishScoped n@ProfNote{} = profNoteScope n
tickishScoped HpcTick{}    = False
tickishScoped Breakpoint{} = True
   -- Breakpoints are scoped: eventually we're going to do call
   -- stacks, but also this helps prevent the simplifier from moving
   -- breakpoints around and changing their result type (see #1531).

mkNoTick :: Tickish id -> Tickish id
mkNoTick n@ProfNote{} = n {profNoteCount = False}
mkNoTick Breakpoint{} = panic "mkNoTick: Breakpoint" -- cannot split a BP
mkNoTick t = t

mkNoScope :: Tickish id -> Tickish id
mkNoScope n@ProfNote{} = n {profNoteScope = False}
mkNoScope Breakpoint{} = panic "mkNoScope: Breakpoint" -- cannot split a BP
mkNoScope t = t

-- | Return True if this source annotation compiles to some code, or will
-- disappear before the backend.
tickishIsCode :: Tickish id -> Bool
tickishIsCode _tickish = True  -- all of them for now

-- | Return True if this Tick can be split into (tick,scope) parts with
-- 'mkNoScope' and 'mkNoTick' respectively.
tickishCanSplit :: Tickish Id -> Bool
tickishCanSplit Breakpoint{} = False
tickishCanSplit _ = True
482
\end{code}
483

484

485 486 487 488 489 490 491 492 493
%************************************************************************
%*									*
\subsection{Transformation rules}
%*									*
%************************************************************************

The CoreRule type and its friends are dealt with mainly in CoreRules,
but CoreFVs, Subst, PprCore, CoreTidy also inspect the representation.

494
\begin{code}
495 496 497 498 499 500 501
-- | 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
502
data CoreRule
503
  = Rule { 
504 505
	ru_name :: RuleName,            -- ^ Name of the rule, for communication with the user
	ru_act  :: Activation,          -- ^ When the rule is active
506

507
	-- Rough-matching stuff
508
	-- see comments with InstEnv.ClsInst( is_cls, is_rough )
509 510
	ru_fn    :: Name,	        -- ^ Name of the 'Id.Id' at the head of this rule
	ru_rough :: [Maybe Name],	-- ^ Name at the head of each argument to the left hand side
511 512
	
	-- Proper-matching stuff
513
	-- see comments with InstEnv.ClsInst( is_tvs, is_tys )
514 515
	ru_bndrs :: [CoreBndr],         -- ^ Variables quantified over
	ru_args  :: [CoreExpr],         -- ^ Left hand side arguments
516 517
	
	-- And the right-hand side
518
	ru_rhs   :: CoreExpr,           -- ^ Right hand side of the rule
519 520
		    			-- Occurrence info is guaranteed correct
					-- See Note [OccInfo in unfoldings and rules]
521 522

	-- Locality
523 524 525 526
        ru_auto :: Bool,	-- ^ @True@  <=> this rule is auto-generated
		   		--   @False@ <=> generated at the users behest
				--   Main effect: reporting of orphan-hood

527
	ru_local :: Bool	-- ^ @True@ iff the fn at the head of the rule is
528
				-- defined in the same module as the rule
529 530 531
				-- and is not an implicit 'Id' (like a record selector,
				-- class operation, or data constructor)

532 533
		-- NB: ru_local is *not* used to decide orphan-hood
		--	c.g. MkIface.coreRuleToIfaceRule
534
    }
535

536 537 538
  -- | Built-in rules are used for constant folding
  -- and suchlike.  They have no free variables.
  | BuiltinRule {               
539 540 541 542
	ru_name  :: RuleName,   -- ^ As above
	ru_fn    :: Name,       -- ^ As above
	ru_nargs :: Int,	-- ^ Number of arguments that 'ru_try' consumes,
				-- if it fires, including type arguments
543
	ru_try  :: Id -> IdUnfoldingFun -> [CoreExpr] -> Maybe CoreExpr
544 545 546 547
		-- ^ 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
    }
548
		-- See Note [Extra args in rule matching] in Rules.lhs
549

550 551 552 553 554
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

twanvl's avatar
twanvl committed
555
isBuiltinRule :: CoreRule -> Bool
556 557
isBuiltinRule (BuiltinRule {}) = True
isBuiltinRule _		       = False
558

559 560
-- | The number of arguments the 'ru_fn' must be applied 
-- to before the rule can match on it
561 562 563 564
ruleArity :: CoreRule -> Int
ruleArity (BuiltinRule {ru_nargs = n}) = n
ruleArity (Rule {ru_args = args})      = length args

565 566
ruleName :: CoreRule -> RuleName
ruleName = ru_name
567

568 569 570
ruleActivation :: CoreRule -> Activation
ruleActivation (BuiltinRule { })       = AlwaysActive
ruleActivation (Rule { ru_act = act }) = act
571 572

-- | The 'Name' of the 'Id.Id' at the head of the rule left hand side
573 574
ruleIdName :: CoreRule -> Name
ruleIdName = ru_fn
575

576 577
isLocalRule :: CoreRule -> Bool
isLocalRule = ru_local
578

579
-- | Set the 'Name' of the 'Id.Id' at the head of the rule left hand side
580 581
setRuleIdName :: Name -> CoreRule -> CoreRule
setRuleIdName nm ru = ru { ru_fn = nm }
582 583 584
\end{code}


585 586 587 588 589 590 591 592 593 594
%************************************************************************
%*                                                                      *
\subsection{Vectorisation declarations}
%*                                                                      *
%************************************************************************

Representation of desugared vectorisation declarations that are fed to the vectoriser (via
'ModGuts').

\begin{code}
595
data CoreVect = Vect      Id   CoreExpr
596 597 598
              | NoVect    Id
              | VectType  Bool TyCon (Maybe TyCon)
              | VectClass TyCon                     -- class tycon
599
              | VectInst  Id                        -- instance dfun (always SCALAR)  !!!FIXME: should be superfluous now
600 601 602
\end{code}


603
%************************************************************************
604 605 606
%*                                                                      *
                Unfoldings
%*                                                                      *
607 608
%************************************************************************

609
The @Unfolding@ type is declared here to avoid numerous loops
610 611

\begin{code}
612 613 614
-- | 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 "CoreUnfold"
615
data Unfolding
616 617 618 619 620 621 622 623 624 625 626 627 628
  = NoUnfolding        -- ^ We have no information about the unfolding

  | 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.

629 630
  | DFunUnfolding       -- The Unfolding of a DFunId  
    			-- See Note [DFun unfoldings]
631 632
      		  	--     df = /\a1..am. \d1..dn. MkD (op1 a1..am d1..dn)
     		      	--     	    	      	       	   (op2 a1..am d1..dn)
633 634 635 636 637 638

        Arity 		-- Arity = m+n, the *total* number of args 
			--   (unusually, both type and value) to the dfun

        DataCon 	-- The dictionary data constructor (possibly a newtype datacon)

639
        [DFunArg CoreExpr]  -- Specification of superclasses and methods, in positional order
640

641 642 643 644
  | 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.)
645 646
	uf_tmpl       :: CoreExpr,	  -- Template; occurrence info is correct
	uf_src        :: UnfoldingSource, -- Where the unfolding came from
647
	uf_is_top     :: Bool,		-- True <=> top level binding
648
	uf_arity      :: Arity,		-- Number of value arguments expected
649 650 651
	uf_is_value   :: Bool,		-- exprIsHNF template (cached); it is ok to discard 
		      			--	a `seq` on this variable
        uf_is_conlike :: Bool,          -- True <=> applicn of constructor or CONLIKE function
652
                                        --      Cached version of exprIsConLike
653
	uf_is_work_free :: Bool,		-- True <=> doesn't waste (much) work to expand 
654
                                        --          inside an inlining
655 656 657 658 659
					-- 	Cached version of exprIsCheap
	uf_expandable :: Bool,		-- True <=> can expand in RULE matching
		      	 		--      Cached version of exprIsExpandable
	uf_guidance   :: UnfoldingGuidance	-- Tells about the *size* of the template.
    }
660 661
  -- ^ An unfolding with redundant cached information. Parameters:
  --
662 663 664
  --  uf_tmpl: Template used to perform unfolding; 
  --           NB: Occurrence info is guaranteed correct: 
  --	           see Note [OccInfo in unfoldings and rules]
665
  --
666
  --  uf_is_top: Is this a top level binding?
667
  --
668
  --  uf_is_value: 'exprIsHNF' template (cached); it is ok to discard a 'seq' on
669 670
  --     this variable
  --
671 672
  --  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'
673
  --
674
  --  uf_guidance:  Tells us about the /size/ of the unfolding template
675

676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
------------------------------------------------
data DFunArg e   -- Given (df a b d1 d2 d3)
  = DFunPolyArg  e      -- Arg is (e a b d1 d2 d3)
  | DFunLamArg   Int    -- Arg is one of [a,b,d1,d2,d3], zero indexed
  deriving( Functor )

  -- 'e' is often CoreExpr, which are usually variables, but can
  -- be trivial expressions instead (e.g. a type application).

dfunArgExprs :: [DFunArg e] -> [e]
dfunArgExprs []                    = []
dfunArgExprs (DFunPolyArg  e : as) = e : dfunArgExprs as
dfunArgExprs (DFunLamArg {}  : as) = dfunArgExprs as


691 692
------------------------------------------------
data UnfoldingSource
693 694 695 696
  = InlineRhs          -- The current rhs of the function
    		       -- Replace uf_tmpl each time around

  | InlineStable       -- From an INLINE or INLINABLE pragma 
697
                       --   INLINE     if guidance is UnfWhen
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
698
                       --   INLINABLE  if guidance is UnfIfGoodArgs/UnfoldNever
699 700 701 702 703 704 705 706 707 708 709 710
                       -- (well, technically an INLINABLE might be made
                       -- UnfWhen if it was small enough, and then
                       -- it will behave like INLINE outside the current
                       -- module, but that is the way automatic unfoldings
                       -- work so it is consistent with the intended
                       -- meaning of INLINABLE).
                       --
    		       -- uf_tmpl may change, but only as a result of
                       -- gentle simplification, it doesn't get updated
                       -- to the current RHS during compilation as with
                       -- InlineRhs.
                       --
711 712 713
    		       -- See Note [InlineRules]

  | InlineCompulsory   -- Something that *has* no binding, so you *must* inline it
714 715 716 717 718 719 720 721 722 723 724 725 726
    		       -- Only a few primop-like things have this property 
                       -- (see MkId.lhs, calls to mkCompulsoryUnfolding).
                       -- Inline absolutely always, however boring the context.

  | InlineWrapper Id   -- This unfolding is a the wrapper in a 
		       --     worker/wrapper split from the strictness analyser
	               -- The Id is the worker-id
		       -- Used to abbreviate the uf_tmpl in interface files
		       --	which don't need to contain the RHS; 
		       --	it can be derived from the strictness info



727
-- | 'UnfoldingGuidance' says when unfolding should take place
728
data UnfoldingGuidance
729 730 731 732 733 734
  = 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 CoreUnfold
      ug_unsat_ok  :: Bool,	-- True <=> ok to inline even if unsaturated
      ug_boring_ok :: Bool      -- True <=> ok to inline even if the context is boring
735
      		-- So True,True means "always"
736
    }
737

738
  | UnfIfGoodArgs {	-- Arose from a normal Id; the info here is the
739 740 741 742 743 744 745 746 747 748 749 750
    		     	-- result of a simple analysis of the RHS

      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.

      ug_size :: Int,	  -- The "size" of the unfolding.

      ug_res :: Int	  -- Scrutinee discount: the discount to substract if the thing is in
    }			  -- a context (case (thing args) of ...),
			  -- (where there are the right number of arguments.)

751
  | UnfNever	    -- The RHS is big, so don't inline it
752 753 754 755 756 757 758 759 760
\end{code}


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
761

762 763 764 765 766 767 768 769 770 771 772 773 774 775
     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
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
776
why we record the number of expected arguments in the DFunUnfolding.
777

simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
778 779 780
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.
781 782

\begin{code}
783 784 785 786
-- Constants for the UnfWhen constructor
needSaturated, unSaturatedOk :: Bool
needSaturated = False
unSaturatedOk = True
787

788 789 790
boringCxtNotOk, boringCxtOk :: Bool
boringCxtOk    = True
boringCxtNotOk = False
791 792

------------------------------------------------
793 794 795 796 797
noUnfolding :: Unfolding
-- ^ There is no known 'Unfolding'
evaldUnfolding :: Unfolding
-- ^ This unfolding marks the associated thing as being evaluated

798 799 800
noUnfolding    = NoUnfolding
evaldUnfolding = OtherCon []

twanvl's avatar
twanvl committed
801
mkOtherCon :: [AltCon] -> Unfolding
802
mkOtherCon = OtherCon
803 804

seqUnfolding :: Unfolding -> ()
805
seqUnfolding (CoreUnfolding { uf_tmpl = e, uf_is_top = top, 
806
		uf_is_value = b1, uf_is_work_free = b2, 
807 808 809
	   	uf_expandable = b3, uf_is_conlike = b4,
                uf_arity = a, uf_guidance = g})
  = seqExpr e `seq` top `seq` b1 `seq` a `seq` b2 `seq` b3 `seq` b4 `seq` seqGuidance g
810

twanvl's avatar
twanvl committed
811
seqUnfolding _ = ()
812

twanvl's avatar
twanvl committed
813
seqGuidance :: UnfoldingGuidance -> ()
814 815
seqGuidance (UnfIfGoodArgs ns n b) = n `seq` sum ns `seq` b `seq` ()
seqGuidance _                      = ()
816 817 818
\end{code}

\begin{code}
819 820 821 822 823 824
isStableSource :: UnfoldingSource -> Bool
-- Keep the unfolding template
isStableSource InlineCompulsory   = True
isStableSource InlineStable       = True
isStableSource (InlineWrapper {}) = True
isStableSource InlineRhs          = False
825
 
826
-- | Retrieves the template of an unfolding: panics if none is known
827
unfoldingTemplate :: Unfolding -> CoreExpr
828 829 830 831
unfoldingTemplate = uf_tmpl

setUnfoldingTemplate :: Unfolding -> CoreExpr -> Unfolding
setUnfoldingTemplate unf rhs = unf { uf_tmpl = rhs }
832

833
-- | Retrieves the template of an unfolding if possible
834
maybeUnfoldingTemplate :: Unfolding -> Maybe CoreExpr
835 836
maybeUnfoldingTemplate (CoreUnfolding { uf_tmpl = expr })       = Just expr
maybeUnfoldingTemplate _                            		= Nothing
837

838 839
-- | The constructors that the unfolding could never be: 
-- returns @[]@ if no information is available
840 841
otherCons :: Unfolding -> [AltCon]
otherCons (OtherCon cons) = cons
twanvl's avatar
twanvl committed
842
otherCons _               = []
843

844 845
-- | Determines if it is certainly the case that the unfolding will
-- yield a value (something in HNF): returns @False@ if unsure
846
isValueUnfolding :: Unfolding -> Bool
847 848 849
	-- Returns False for OtherCon
isValueUnfolding (CoreUnfolding { uf_is_value = is_evald }) = is_evald
isValueUnfolding _                                          = False
850

851 852 853
-- | Determines if it possibly the case that the unfolding will
-- yield a value. Unlike 'isValueUnfolding' it returns @True@
-- for 'OtherCon'
854
isEvaldUnfolding :: Unfolding -> Bool
855 856 857 858
	-- Returns True for OtherCon
isEvaldUnfolding (OtherCon _)		                    = True
isEvaldUnfolding (CoreUnfolding { uf_is_value = is_evald }) = is_evald
isEvaldUnfolding _                                          = False
859

860 861 862 863 864 865 866
-- | @True@ if the unfolding is a constructor application, the application
-- of a CONLIKE function or 'OtherCon'
isConLikeUnfolding :: Unfolding -> Bool
isConLikeUnfolding (OtherCon _)                             = True
isConLikeUnfolding (CoreUnfolding { uf_is_conlike = con })  = con
isConLikeUnfolding _                                        = False

867
-- | Is the thing we will unfold into certainly cheap?
868
isCheapUnfolding :: Unfolding -> Bool
869 870
isCheapUnfolding (CoreUnfolding { uf_is_work_free = is_wf }) = is_wf
isCheapUnfolding _                                           = False
871 872

isExpandableUnfolding :: Unfolding -> Bool
873 874 875
isExpandableUnfolding (CoreUnfolding { uf_expandable = is_expable }) = is_expable
isExpandableUnfolding _                                              = False

876 877 878 879 880 881 882
expandUnfolding_maybe :: Unfolding -> Maybe CoreExpr
-- Expand an expandable unfolding; this is used in rule matching 
--   See Note [Expanding variables] in Rules.lhs
-- The key point here is that CONLIKE things can be expanded
expandUnfolding_maybe (CoreUnfolding { uf_expandable = True, uf_tmpl = rhs }) = Just rhs
expandUnfolding_maybe _                                                       = Nothing

883 884 885 886
isStableCoreUnfolding_maybe :: Unfolding -> Maybe UnfoldingSource
isStableCoreUnfolding_maybe (CoreUnfolding { uf_src = src })
   | isStableSource src   = Just src
isStableCoreUnfolding_maybe _ = Nothing
887 888 889 890

isCompulsoryUnfolding :: Unfolding -> Bool
isCompulsoryUnfolding (CoreUnfolding { uf_src = InlineCompulsory }) = True
isCompulsoryUnfolding _                                             = False
891

892 893 894
isStableUnfolding :: Unfolding -> Bool
-- True of unfoldings that should not be overwritten 
-- by a CoreUnfolding for the RHS of a let-binding
895
isStableUnfolding (CoreUnfolding { uf_src = src }) = isStableSource src
896 897
isStableUnfolding (DFunUnfolding {})		   = True
isStableUnfolding _                                = False
898

899 900 901 902 903 904
unfoldingArity :: Unfolding -> Arity
unfoldingArity (CoreUnfolding { uf_arity = arity }) = arity
unfoldingArity _	      		   	    = panic "unfoldingArity"

isClosedUnfolding :: Unfolding -> Bool		-- No free variables
isClosedUnfolding (CoreUnfolding {}) = False
905
isClosedUnfolding (DFunUnfolding {}) = False
906
isClosedUnfolding _                  = True
907

908
-- | Only returns False if there is no unfolding information available at all
909 910
hasSomeUnfolding :: Unfolding -> Bool
hasSomeUnfolding NoUnfolding = False
twanvl's avatar
twanvl committed
911
hasSomeUnfolding _           = True
912

913
neverUnfoldGuidance :: UnfoldingGuidance -> Bool
914 915
neverUnfoldGuidance UnfNever = True
neverUnfoldGuidance _        = False
916 917 918 919

canUnfold :: Unfolding -> Bool
canUnfold (CoreUnfolding { uf_guidance = g }) = not (neverUnfoldGuidance g)
canUnfold _  				      = False
920 921
\end{code}

922
Note [InlineRules]
923 924 925 926 927 928 929
~~~~~~~~~~~~~~~~~
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,
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
930 931 932 933 934
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 InlineRule saying "all . map p",
which deforests well at the call site.
935

simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
936
So INLINE pragma gives rise to an InlineRule, which captures the original RHS.
937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963

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.

See also Note [Inlining an InlineRule] in CoreUnfold.


Note [OccInfo in unfoldings and rules]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In unfoldings and rules, we guarantee that the template is occ-analysed,
so that the occurence info on the binders is correct.  This is important,
because the Simplifier does not re-analyse the template when using it. If
the occurrence info is wrong
  - We may get more simpifier 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

964

965 966
%************************************************************************
%*									*
Simon Peyton Jones's avatar
Simon Peyton Jones committed
967
                  AltCon
968 969 970 971 972 973 974 975 976 977 978 979
%*									*
%************************************************************************

\begin{code}
-- The Ord is needed for the FiniteMap used in the lookForConstructor
-- in SimplEnv.  If you declared that lookForConstructor *ignores*
-- constructor-applications with LitArg args, then you could get
-- rid of this Ord.

instance Outputable AltCon where
  ppr (DataAlt dc) = ppr dc
  ppr (LitAlt lit) = ppr lit
Ian Lynagh's avatar
Ian Lynagh committed
980
  ppr DEFAULT      = ptext (sLit "__DEFAULT")
981

982
cmpAlt :: (AltCon, a, b) -> (AltCon, a, b) -> Ordering
983 984
cmpAlt (con1, _, _) (con2, _, _) = con1 `cmpAltCon` con2

985
ltAlt :: (AltCon, a, b) -> (AltCon, a, b) -> Bool
twanvl's avatar
twanvl committed
986
ltAlt a1 a2 = (a1 `cmpAlt` a2) == LT
987 988

cmpAltCon :: AltCon -> AltCon -> Ordering
989
-- ^ Compares 'AltCon's within a single list of alternatives
990
cmpAltCon DEFAULT      DEFAULT	   = EQ
twanvl's avatar
twanvl committed
991
cmpAltCon DEFAULT      _           = LT
992 993 994 995 996 997 998 999 1000

cmpAltCon (DataAlt d1) (DataAlt d2) = dataConTag d1 `compare` dataConTag d2
cmpAltCon (DataAlt _)  DEFAULT      = GT
cmpAltCon (LitAlt  l1) (LitAlt  l2) = l1 `compare` l2
cmpAltCon (LitAlt _)   DEFAULT      = GT

cmpAltCon con1 con2 = WARN( True, text "Comparing incomparable AltCons" <+> 
			 	  ppr con1 <+> ppr con2 )
		      LT
1001 1002
\end{code}

1003 1004
%************************************************************************
%*									*
1005
\subsection{Useful synonyms}
1006 1007 1008
%*									*
%************************************************************************

1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028
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.  

1029
\begin{code}
1030 1031
type CoreProgram = [CoreBind]	-- See Note [CoreProgram]

1032 1033
-- | The common case for the type of binders and variables when
-- we are manipulating the Core language within GHC
1034
type CoreBndr = Var
1035
-- | Expressions where binders are 'CoreBndr's
1036
type CoreExpr = Expr CoreBndr
1037
-- | Argument expressions where binders are 'CoreBndr's
1038
type CoreArg  = Arg  CoreBndr
1039
-- | Binding groups where binders are 'CoreBndr's
1040
type CoreBind = Bind CoreBndr
1041
-- | Case alternatives where binders are 'CoreBndr's
1042
type CoreAlt  = Alt  CoreBndr
1043 1044
\end{code}

1045 1046 1047 1048 1049
%************************************************************************
%*									*
\subsection{Tagging}
%*									*
%************************************************************************
1050 1051

\begin{code}
1052
-- | Binders are /tagged/ with a t
1053
data TaggedBndr t = TB CoreBndr t	-- TB for "tagged binder"
1054

1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
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 (TB b l) = char '<' <> ppr b <> comma <> ppr l <> char '>'

instance Outputable b => OutputableBndr (TaggedBndr b) where
  pprBndr _ b = ppr b	-- Simple
1065 1066
  pprInfixOcc  b = ppr b
  pprPrefixOcc b = ppr b
1067 1068
\end{code}

1069

1070 1071
%************************************************************************
%*									*
1072
\subsection{Core-constructing functions with checking}
1073 1074
%*									*
%************************************************************************
1075 1076

\begin{code}
1077
-- | Apply a list of argument expressions to a function expression in a nested fashion. Prefer to
Michal Terepeta's avatar
Michal Terepeta committed
1078
-- use 'MkCore.mkCoreApps' if possible
1079
mkApps    :: Expr b -> [Arg b]  -> Expr b
1080
-- | Apply a list of type argument expressions to a function expression in a nested fashion
1081
mkTyApps  :: Expr b -> [Type]   -> Expr b
1082 1083
-- | Apply a list of coercion argument expressions to a function expression in a nested fashion
mkCoApps  :: Expr b -> [Coercion] -> Expr b
1084
-- | Apply a list of type or value variables to a function expression in a nested fashion
1085
mkVarApps :: Expr b -> [Var] -> Expr b
1086 1087 1088
-- | Apply a list of argument expressions to a data constructor in a nested fashion. Prefer to
-- use 'MkCore.mkCoreConApps' if possible
mkConApp      :: DataCon -> [Arg b] -> Expr b
1089 1090 1091

mkApps    f args = foldl App		  	   f args
mkTyApps  f args = foldl (\ e a -> App e (Type a)) f args
1092
mkCoApps  f args = foldl (\ e a -> App e (Coercion a)) f args
1093
mkVarApps f vars = foldl (\ e a -> App e (varToCoreExpr a)) f vars
1094 1095
mkConApp con args = mkApps (Var (dataConWorkId con)) args

1096

1097 1098
-- | Create a machine integer literal expression of type @Int#@ from an @Integer@.
-- If you want an expression of type @Int@ use 'MkCore.mkIntExpr'
1099
mkIntLit      :: Integer -> Expr b
1100 1101
-- | Create a machine integer literal expression of type @Int#@ from an @Int@.
-- If you want an expression of type @Int@ use 'MkCore.mkIntExpr'
1102
mkIntLitInt   :: Int     -> Expr b
1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116

mkIntLit    n = Lit (mkMachInt n)
mkIntLitInt n = Lit (mkMachInt (toInteger n))

-- | Create a machine word literal expression of type  @Word#@ from an @Integer@.
-- If you want an expression of type @Word@ use 'MkCore.mkWordExpr'
mkWordLit     :: Integer -> Expr b
-- | Create a machine word literal expression of type  @Word#@ from a @Word@.
-- If you want an expression of type @Word@ use 'MkCore.mkWordExpr'
mkWordLitWord :: Word -> Expr b

mkWordLit     w = Lit (mkMachWord w)
mkWordLitWord w = Lit (mkMachWord (toInteger w))

1117 1118 1119 1120 1121 1122
mkWord64LitWord64 :: Word64 -> Expr b
mkWord64LitWord64 w = Lit (mkMachWord64 (toInteger w))

mkInt64LitInt64 :: Int64 -> Expr b
mkInt64LitInt64 w = Lit (mkMachInt64 (toInteger w))

1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153
-- | Create a machine character literal expression of type @Char#@.
-- If you want an expression of type @Char@ use 'MkCore.mkCharExpr'
mkCharLit :: Char -> Expr b
-- | Create a machine string literal expression of type @Addr#@.
-- If you want an expression of type @String@ use 'MkCore.mkStringExpr'
mkStringLit :: String -> Expr b

mkCharLit   c = Lit (mkMachChar c)
mkStringLit s = Lit (mkMachString s)

-- | Create a machine single precision literal expression of type @Float#@ from a @Rational@.
-- If you want an expression of type @Float@ use 'MkCore.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 'MkCore.mkFloatExpr'
mkFloatLitFloat :: Float -> Expr b

mkFloatLit      f = Lit (mkMachFloat f)
mkFloatLitFloat f = Lit (mkMachFloat (toRational f))

-- | Create a machine double precision literal expression of type @Double#@ from a @Rational@.
-- If you want an expression of type @Double@ use 'MkCore.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 'MkCore.mkDoubleExpr'
mkDoubleLitDouble :: Double -> Expr b

mkDoubleLit       d = Lit (mkMachDouble d)
mkDoubleLitDouble d = Lit (mkMachDouble (toRational d))

-- | Bind all supplied binding groups over an expression in a nested let expression. Prefer to
Michal Terepeta's avatar
Michal Terepeta committed
1154
-- use 'MkCore.mkCoreLets' if possible
1155
mkLets	      :: [Bind b] -> Expr b -> Expr b
1156
-- | Bind all supplied binders over an expression in a nested lambda expression. Prefer to
Michal Terepeta's avatar
Michal Terepeta committed
1157
-- use 'MkCore.mkCoreLams' if possible
1158
mkLams	      :: [b] -> Expr b -> Expr b
1159

1160 1161 1162
mkLams binders body = foldr Lam body binders
mkLets binds body   = foldr Let body binds

1163

1164 1165 1166 1167 1168
-- | Create a binding group where a type variable is bound to a type. Per "CoreSyn#type_let",
-- this can only be used to bind something in a non-recursive @let@ expression
mkTyBind :: TyVar -> Type -> CoreBind
mkTyBind tv ty      = NonRec tv (Type ty)

1169 1170 1171 1172 1173
-- | Create a binding group where a type variable is bound to a type. Per "CoreSyn#type_let",
-- this can only be used to bind something in a non-recursive @let@ expression
mkCoBind :: CoVar -> Coercion -> CoreBind
mkCoBind cv co      = NonRec cv (Coercion co)

1174
-- | Convert a binder into either a 'Var' or 'Type' 'Expr' appropriately
1175
varToCoreExpr :: CoreBndr -> Expr b
1176 1177 1178
varToCoreExpr v | isTyVar v = Type (mkTyVarTy v)
                | isCoVar v = Coercion (mkCoVarCo v)
                | otherwise = ASSERT( isId v ) Var v
1179 1180 1181

varsToCoreExprs :: [CoreBndr] -> [Expr b]
varsToCoreExprs vs = map varToCoreExpr vs
1182 1183
\end{code}

1184

1185 1186
%************************************************************************
%*									*
1187
\subsection{Simple access functions}
1188 1189 1190 1191
%*									*
%************************************************************************

\begin{code}
1192
-- | Extract every variable by this group
1193
bindersOf  :: Bind b -> [b]
1194 1195
bindersOf (NonRec binder _) = [binder]
bindersOf (Rec pairs)       = [binder | (binder, _) <- pairs]
1196

1197
-- | 'bindersOf' applied to a list of binding groups