tock-mirror/frontends/RainTypes.hs
Neil Brown 89c25e3f6c Added a type-class for retrieving the (AST) type of things
This patch hides all the old typeOfExpression, typeOfName, typeOfVariable, etc, and unifies them into a single type-class with an "astTypeOf" function.  The type-class is currently named Typed, but that can easily be changed (it's only explicitly referred to in the Types module).  The patch is essentially the type-class with a giant find-and-replace on the other modules.
2008-05-17 11:41:52 +00:00

414 lines
20 KiB
Haskell

{-
Tock: a compiler for parallel languages
Copyright (C) 2007 University of Kent
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see <http://www.gnu.org/licenses/>.
-}
module RainTypes where
import Control.Monad.State
import Data.Generics
import qualified AST as A
import CompState
import Errors
import EvalConstants
import Metadata
import Pass
import ShowCode
import Traversal
import Types
-- | A pass that records inferred types. Currently the only place where types are inferred is in seqeach\/pareach loops.
recordInfNameTypes :: Data t => t -> PassM t
recordInfNameTypes = everywhereM (mkM recordInfNameTypes')
where
recordInfNameTypes' :: A.Replicator -> PassM A.Replicator
recordInfNameTypes' input@(A.ForEach m n e)
= do arrType <- astTypeOf e
innerT <- case arrType of
A.List t -> return t
_ -> diePC m $ formatCode "Cannot do a foreach loop over a non-list type: %" arrType
defineName n A.NameDef {A.ndMeta = m, A.ndName = A.nameName n, A.ndOrigName = A.nameName n,
A.ndNameType = A.VariableName, A.ndType = (A.Declaration m innerT),
A.ndAbbrevMode = A.Abbrev, A.ndPlacement = A.Unplaced}
return input
recordInfNameTypes' r = return r
-- | Folds all constants.
constantFoldPass :: Data t => t -> PassM t
constantFoldPass = applyDepthM doExpression
where
doExpression :: A.Expression -> PassM A.Expression
doExpression = (liftM (\(x,_,_) -> x)) . constantFold
-- | Annotates all integer literal types
annotateIntLiteralTypes :: Data t => t -> PassM t
annotateIntLiteralTypes = applyDepthM doExpression
where
--Function is separated out to easily provide the type description of Integer
powOf2 :: Integer -> Integer
powOf2 x = 2 ^ x
doExpression :: A.Expression -> PassM A.Expression
doExpression (A.Literal m t (A.IntLiteral m' s))
= do t' <-
if (t == A.Int64) then --it's a signed literal
(if (n >= powOf2 63 || n < (-(powOf2 63)))
then dieP m $ "Signed integer literal too large to fit into 64 bits: " ++ s
else
if (n < (-(powOf2 31)) || n >= powOf2 31)
then return A.Int64
else
if (n < (-(powOf2 15)) || n >= powOf2 15)
then return A.Int32
else
if (n < (-(powOf2 7)) || n >= powOf2 7)
then return A.Int16
else return A.Int8
)
else
dieP m $ "Unsigned literals currently unsupported"
return $ A.Literal m t' (A.IntLiteral m' s)
where
n :: Integer
n = read s
doExpression e = return e
-- | Annotates all list literals and list ranges with their type
annotateListLiteralTypes :: Data t => t -> PassM t
annotateListLiteralTypes = applyDepthM doExpression
where
doExpression :: A.Expression -> PassM A.Expression
doExpression (A.Literal m _ (A.ListLiteral m' es))
= do ts <- mapM astTypeOf es
sharedT <- case (ts, leastGeneralSharedTypeRain ts) of
(_, Just t) -> return t
([], Nothing) -> return A.Any
(_, Nothing) -> diePC m'
$ formatCode
"Can't determine a common type for the list literal from: %"
ts
es' <- mapM (coerceIfNecessary sharedT) (zip ts es)
return $ A.Literal m (A.List sharedT) $ A.ListLiteral m' es'
doExpression (A.ExprConstr m (A.RangeConstr m' t b e))
= do bt <- astTypeOf b
et <- astTypeOf e
sharedT <- case leastGeneralSharedTypeRain [bt, et] of
Just t -> return t
Nothing -> diePC m'
$ formatCode
"Can't determine a common type for the range from: % %"
bt et
b' <- coerceIfNecessary sharedT (bt, b)
e' <- coerceIfNecessary sharedT (et, e)
return $ A.ExprConstr m $ A.RangeConstr m' (A.List sharedT) b' e'
doExpression e = return e
coerceIfNecessary :: A.Type -> (A.Type, A.Expression) -> PassM A.Expression
coerceIfNecessary to (from, e)
| to == from = return e
| otherwise = coerceType " in list literal" to from e
-- | A pass that finds all the 'A.ProcCall' and 'A.FunctionCall' in the
-- AST, and checks that the actual parameters are valid inputs, given
-- the 'A.Formal' parameters in the process's type
matchParamPass :: Data t => t -> PassM t
matchParamPass = everywhereM ((mkM matchParamPassProc) `extM` matchParamPassFunc)
where
--Picks out the parameters of a process call, checks the number is correct, and maps doParam over them
matchParamPassProc :: A.Process -> PassM A.Process
matchParamPassProc (A.ProcCall m n actualParams)
= do def <- lookupNameOrError n $ dieP m ("Process name is unknown: \"" ++ (show $ A.nameName n) ++ "\"")
case A.ndType def of
A.Proc _ _ expectedParams _ ->
if (length expectedParams) == (length actualParams)
then do transActualParams <- mapM (doParam m (A.nameName n)) (zip3 [0..] expectedParams actualParams)
return $ A.ProcCall m n transActualParams
else dieP m $ "Wrong number of parameters given to process call; expected: " ++ show (length expectedParams) ++ " but found: " ++ show (length actualParams)
_ -> dieP m $ "You cannot run things that are not processes, such as: \"" ++ (show $ A.nameName n) ++ "\""
matchParamPassProc p = return p
--Picks out the parameters of a function call, checks the number is correct, and maps doExpParam over them
matchParamPassFunc :: A.Expression -> PassM A.Expression
matchParamPassFunc (A.FunctionCall m n actualParams)
= do def <- lookupNameOrError n $ dieP m ("Function name is unknown: \"" ++ (show $ A.nameName n) ++ "\"")
case A.ndType def of
A.Function _ _ _ expectedParams _ ->
if (length expectedParams) == (length actualParams)
then do transActualParams <- mapM (doExpParam m (A.nameName n)) (zip3 [0..] expectedParams actualParams)
return $ A.FunctionCall m n transActualParams
else dieP m $ "Wrong number of parameters given to function call; expected: " ++ show (length expectedParams) ++ " but found: " ++ show (length actualParams)
_ -> dieP m $ "Attempt to make a function call with something"
++ " that is not a function: \"" ++ A.nameName n
++ "\"; is actually: " ++ showConstr (toConstr $
A.ndType def)
matchParamPassFunc e = return e
--Checks the type of a parameter (A.Actual), and inserts a cast if it is safe to do so
doParam :: Meta -> String -> (Int,A.Formal, A.Actual) -> PassM A.Actual
doParam m n (index, A.Formal formalAbbrev formalType formalName, A.ActualVariable v)
= do actualType <- astTypeOf v
if (actualType == formalType)
then return $ A.ActualVariable v
else (liftM A.ActualExpression) $ doCast index formalType actualType (A.ExprVariable (findMeta v) v )
doParam m n (index, for@(A.Formal _ formalType _), A.ActualExpression e)
= (liftM A.ActualExpression) $ doExpParam m n (index, for, e)
--Checks the type of a parameter (A.Expression), and inserts a cast if it is safe to do so
doExpParam :: Meta -> String -> (Int, A.Formal, A.Expression) -> PassM A.Expression
doExpParam m n (index, A.Formal formalAbbrev formalType formalName, e)
= do actualType <- astTypeOf e
if (actualType == formalType)
then return e
else doCast index formalType actualType e
doCast :: Int -> A.Type -> A.Type -> A.Expression -> PassM A.Expression
doCast index = coerceType $ " for parameter (zero-based): " ++ (show index)
--Adds a cast between two types if it is safe to do so, otherwise gives an error
coerceType :: String -> A.Type -> A.Type -> A.Expression -> PassM A.Expression
coerceType customMsg to from item
= if isImplicitConversionRain from to
then return $ A.Conversion (findMeta item) A.DefaultConversion to item
else diePC (findMeta item) $ (liftM concat) $ sequence [formatCode "Could not perform implicit cast from supplied type: % to expected type: %" from to, return customMsg]
-- | Checks the types in expressions
checkExpressionTypes :: Data t => t -> PassM t
checkExpressionTypes = applyDepthM checkExpression
where
-- | Checks the types of an expression where at least one type involved
-- is Time.
checkTimeExpression :: Meta -> A.DyadicOp -> (A.Type, A.Expression) ->
(A.Type, A.Expression) -> PassM A.Expression
checkTimeExpression m op (tlhs, lhs) (trhs, rhs)
= case (validOpWithTime op tlhs trhs) of
Nothing -> diePC m $ formatCode
"Operator: \"%\" is not valid on types: \"%\" and \"%\"" op tlhs trhs
Just (destLHS, destRHS) ->
if (isImplicitConversionRain tlhs destLHS)
&& (isImplicitConversionRain trhs destRHS)
then return $ A.Dyadic m op (convert destLHS tlhs lhs)
(convert destRHS trhs rhs)
else diePC m $ formatCode
"Operator: \"%\" is not valid on types: \"%\" and \"%\" (implicit conversions not possible)"
op tlhs trhs
checkExpression :: A.Expression -> PassM A.Expression
checkExpression e@(A.Dyadic m op lhs rhs)
= do tlhs <- astTypeOf lhs
trhs <- astTypeOf rhs
if (tlhs == A.Time || trhs == A.Time)
-- Expressions with times can have asymmetric types,
-- so we handle them specially:
then checkTimeExpression m op (tlhs, lhs) (trhs, rhs)
else
if (tlhs == trhs)
then
-- Types identical. At this point we consider whether the
-- user is adding two lists (in which case, correct the
-- operator), otherwise we just need to check the operator
-- is valid on the types (to avoid two channels of the same
-- type being added, for example)
case (tlhs, op) of
(A.List _, A.Plus) -> return $ A.Dyadic m A.Concat lhs rhs
_ -> if validOpSameType op tlhs
then return e
else diePC m $ formatCode
"Operator: \"%\" is not valid on type: \"%\""
op tlhs
-- Types differ. If they are integers, we can look for
-- a common (more general) type for both of them to be cast
-- up into in order to perform the operation.
else if (isIntegerType tlhs && isIntegerType trhs)
then case (leastGeneralSharedTypeRain [tlhs,trhs]) of
Nothing -> diePC m $ formatCode "Cannot find a suitable type to convert expression to, types are: % and %" tlhs trhs
Just t -> if validOpSameType op t then return $ A.Dyadic m op (convert t tlhs lhs) (convert t trhs rhs) else diePC m $
formatCode "Operator: \"%\" is not valid on type: \"%\"" op tlhs
else --The operands are not equal, and are not integers, and neither of them is a time type. Therefore this must be an error:
diePC m $ formatCode "Mis-matched types; no operator applies to types: % and %" tlhs trhs
checkExpression e@(A.Monadic m op rhs)
= do trhs <- astTypeOf rhs
if (op == A.MonadicMinus)
then case trhs of
A.Byte -> return $ A.Monadic m op $ convert A.Int16 trhs rhs
A.UInt16 -> return $ A.Monadic m op $ convert A.Int32 trhs rhs
A.UInt32 -> return $ A.Monadic m op $ convert A.Int64 trhs rhs
A.UInt64 -> diePC m $ formatCode "Cannot apply unary minus to type: % because there is no type large enough to safely contain the result" trhs
_ -> if (isIntegerType trhs) then return e else diePC m $ formatCode "Trying to apply unary minus to non-integer type: %" trhs
else if (op == A.MonadicNot)
then
case trhs of
A.Bool -> return e
_ -> diePC m $ formatCode "Cannot apply unary not to non-boolean type: %" trhs
else dieP m $ "Invalid Rain operator: \"" ++ show op ++ "\""
checkExpression e@(A.Conversion m cm dest rhs)
= do src <- astTypeOf rhs
if (src == dest)
then return e
else if isImplicitConversionRain src dest
then return e
else diePC m $ formatCode "Invalid cast from: % to: %"
src dest
checkExpression e = return e
convert :: A.Type -> A.Type -> A.Expression -> A.Expression
convert dest src e = if (dest == src)
then e
else A.Conversion (findMeta e) A.DefaultConversion dest e
validOpSameType :: A.DyadicOp -> A.Type -> Bool
validOpSameType A.Plus t = isIntegerType t
validOpSameType A.Minus t = isIntegerType t
validOpSameType A.Times t = isIntegerType t && t /= A.Time
validOpSameType A.Div t = isIntegerType t && t /= A.Time
validOpSameType A.Rem t = isIntegerType t && t /= A.Time
validOpSameType A.Eq _ = True
validOpSameType A.NotEq _ = True
validOpSameType A.Less t = haveOrder t
validOpSameType A.LessEq t = haveOrder t
validOpSameType A.More t = haveOrder t
validOpSameType A.MoreEq t = haveOrder t
validOpSameType A.And A.Bool = True
validOpSameType A.Or A.Bool = True
validOpSameType _ _ = False
-- | Takes an operator, the types of LHS and RHS, and returns Nothing if no cast will fix it,
-- or Just (needTypeLHS,needTypeRHS) for what types will be okay
validOpWithTime :: A.DyadicOp -> A.Type -> A.Type -> Maybe (A.Type,A.Type)
validOpWithTime A.Times A.Time _ = Just (A.Time, A.Int64)
validOpWithTime A.Times _ A.Time = Just (A.Int64, A.Time)
validOpWithTime A.Div A.Time _ = Just (A.Time, A.Int64)
--Any other operators involving Time are symmetric:
validOpWithTime op tlhs trhs = if (tlhs == trhs && validOpSameType op tlhs) then Just (tlhs,trhs) else Nothing
haveOrder :: A.Type -> Bool
haveOrder t = (isIntegerType t) || (t == A.Time)
-- | Checks the types in assignments
checkAssignmentTypes :: Data t => t -> PassM t
checkAssignmentTypes = applyDepthM checkAssignment
where
checkAssignment :: A.Process -> PassM A.Process
checkAssignment ass@(A.Assign m [v] (A.ExpressionList m' [e]))
= do trhs <- astTypeOf e
tlhs <- astTypeOf v
am <- abbrevModeOfVariable v
when (am == A.ValAbbrev) $
diePC m $ formatCode "Cannot assign to a constant variable: %" v
if (tlhs == trhs)
then return ass
else do rhs' <- coerceType " in assignment" tlhs trhs e
return $ A.Assign m [v] (A.ExpressionList m' [rhs'])
checkAssignment (A.Assign m _ _) = dieInternal (Just m,"Rain checker found occam-style assignment")
checkAssignment st = return st
-- | Checks the types in if and while conditionals
checkConditionalTypes :: Data t => t -> PassM t
checkConditionalTypes = applyDepthM2 checkWhile checkIf
where
checkWhile :: A.Process -> PassM A.Process
checkWhile w@(A.While m exp _)
= do t <- astTypeOf exp
if (t == A.Bool)
then return w
else dieP m "Expression in while conditional must be of boolean type"
checkWhile p = return p
checkIf :: A.Choice -> PassM A.Choice
checkIf c@(A.Choice m exp _)
= do t <- astTypeOf exp
if (t == A.Bool)
then return c
else dieP m "Expression in if conditional must be of boolean type"
-- | Checks the types in inputs and outputs, including inputs in alts
checkCommTypes :: Data t => t -> PassM t
checkCommTypes = applyDepthM2 checkInputOutput checkAltInput
where
checkInput :: A.Variable -> A.Variable -> Meta -> a -> PassM a
checkInput chanVar destVar m p
= do chanType <- astTypeOf chanVar
destType <- astTypeOf destVar
case chanType of
A.Chan dir _ innerType ->
if (dir == A.DirOutput)
then dieP m $ "Tried to input from the writing end of a channel: " ++ show chanVar
else
if (innerType == destType)
then return p
else diePC m $ formatCode "Mis-matching types; channel: \"%\" has inner-type: % but destination variable: \"%\" has type: %"
chanVar innerType destVar destType
_ -> dieP m $ "Tried to input from a variable that is not of type channel: " ++ show chanVar
checkWait :: A.InputMode -> PassM ()
checkWait (A.InputTimerFor m exp)
= do t <- astTypeOf exp
when (t /= A.Time) $
diePC m $ formatCode "Tried to wait for something that was not of time type: %"
t
checkWait (A.InputTimerAfter m exp)
= do t <- astTypeOf exp
when (t /= A.Time) $
diePC m $ formatCode "Tried to wait for something that was not of time type: %"
t
checkWait (A.InputTimerRead m (A.InVariable _ v))
= do t <- astTypeOf v
when (t /= A.Time) $
diePC m $ formatCode "Tried to wait for something that was not of time type: %"
t
checkWait _ = return ()
checkInputOutput :: A.Process -> PassM A.Process
checkInputOutput p@(A.Input m chanVar (A.InputSimple _ [A.InVariable _ destVar]))
= checkInput chanVar destVar m p
checkInputOutput p@(A.Input _ _ im@(A.InputTimerFor {}))
= do checkWait im
return p
checkInputOutput p@(A.Input _ _ im@(A.InputTimerAfter {}))
= do checkWait im
return p
checkInputOutput p@(A.Input _ _ im@(A.InputTimerRead {}))
= do checkWait im
return p
checkInputOutput p@(A.Output m chanVar [A.OutExpression m' srcExp])
= do chanType <- astTypeOf chanVar
srcType <- astTypeOf srcExp
case chanType of
A.Chan dir _ innerType ->
if (dir == A.DirInput)
then dieP m $ "Tried to output to the reading end of a channel: " ++ show chanVar
else
if (innerType == srcType)
then return p
else do castExp <- coerceType " for writing to channel" innerType srcType srcExp
return $ A.Output m chanVar [A.OutExpression m' castExp]
_ -> dieP m $ "Tried to output to a variable that is not of type channel: " ++ show chanVar
checkInputOutput p = return p
checkAltInput :: A.Alternative -> PassM A.Alternative
checkAltInput a@(A.Alternative m _ chanVar (A.InputSimple _ [A.InVariable _ destVar]) body)
= checkInput chanVar destVar m a
checkAltInput a@(A.Alternative m _ _ im@(A.InputTimerFor {}) _)
= do checkWait im
return a
checkAltInput a@(A.Alternative m _ _ im@(A.InputTimerAfter {}) _)
= do checkWait im
return a
checkAltInput a = return a