sv2v/src/Convert/PackedArray.hs

259 lines
10 KiB
Haskell

{- sv2v
- Author: Zachary Snow <zach@zachjs.com>
-
- Conversion for flattening multi-dimensional packed arrays
-
- This removes one dimension per identifier at a time. This works fine because
- the conversions are repeatedly applied.
-
- We previously had a very complex conversion which used `generate` to make
- flattened and unflattened versions of the array as necessary. This has now
- been "simplified" to always flatten the array, and then rewrite all usages of
- the array as appropriate.
-
- Note that the ranges being combined may not be of the form [hi:lo], and need
- not even be the same direction! Because of this, we have to flip arround
- the indices of certain accesses.
-
- TODO: Name conflicts between functions/tasks and the description that
- contains them likely breaks this conversion.
-}
module Convert.PackedArray (convert) where
import Control.Monad.State
import Data.Tuple (swap)
import qualified Data.Map.Strict as Map
import Convert.Traverse
import Language.SystemVerilog.AST
type DimMap = Map.Map Identifier (Type, Range)
data Info = Info
{ sTypeDims :: DimMap
} deriving Show
convert :: AST -> AST
convert = traverseDescriptions convertDescription
convertDescription :: Description -> Description
convertDescription (description @ (Part _ _ _ _ _ _)) =
traverseModuleItems (flattenModuleItem info . rewriteModuleItem info) description
where
-- collect all possible information info our Info structure
info =
execState (collectModuleItemsM collectDecl description) $
execState (collectModuleItemsM collectTF description) $
(Info Map.empty)
convertDescription description = description
-- collects port direction and packed-array dimension info into the state
collectDecl :: ModuleItem -> State Info ()
collectDecl (MIDecl (Variable _ t ident _ _)) = do
let (tf, rs) = typeRanges t
if not (typeIsImplicit t) && length rs > 1
then
let dets = (tf $ tail rs, head rs) in
modify $ \s -> s { sTypeDims = Map.insert ident dets (sTypeDims s) }
else return ()
collectDecl _ = return ()
-- collects task and function info into the state
collectTF :: ModuleItem -> State Info ()
collectTF (MIPackageItem (Function _ t x decls _)) = do
collectDecl (MIDecl $ Variable Local t x [] Nothing)
_ <- mapM collectDecl $ map MIDecl decls
return ()
collectTF (MIPackageItem (Task _ _ decls _)) = do
_ <- mapM collectDecl $ map MIDecl decls
return ()
collectTF _ = return ()
-- rewrite a module item if it contains a declaration to flatten
flattenModuleItem :: Info -> ModuleItem -> ModuleItem
flattenModuleItem info (MIPackageItem (Function ml t x decls stmts)) =
MIPackageItem $ Function ml t' x decls' stmts
where
MIPackageItem (Task _ _ decls' _) =
flattenModuleItem info $ MIPackageItem $ Task ml x decls stmts
MIDecl (Variable Local t' _ [] Nothing) =
flattenModuleItem info $ MIDecl (Variable Local t x [] Nothing)
flattenModuleItem info (MIPackageItem (Task ml x decls stmts)) =
MIPackageItem $ Task ml x decls' stmts
where
decls' = map mapDecl decls
mapDecl :: Decl -> Decl
mapDecl decl = decl'
where MIDecl decl' = flattenModuleItem info $ MIDecl decl
flattenModuleItem info (origDecl @ (MIDecl (Variable dir t ident a me))) =
if Map.notMember ident typeDims
then origDecl
else flatDecl
where
Info typeDims = info
(tf, rs) = typeRanges t
flatDecl = MIDecl $ Variable dir (tf $ flattenRanges rs) ident a me
flattenModuleItem _ other = other
typeIsImplicit :: Type -> Bool
typeIsImplicit (Implicit _ _) = True
typeIsImplicit _ = False
-- combines (flattens) the bottom two ranges in the given list of ranges
flattenRanges :: [Range] -> [Range]
flattenRanges rs =
if length rs >= 2
then rs'
else error $ "flattenRanges on too small list: " ++ (show rs)
where
r1 = head rs
r2 = head $ tail rs
rYY = flattenRangesHelp r1 r2
rYN = flattenRangesHelp r1 (swap r2)
rNY = flattenRangesHelp (swap r1) r2
rNN = flattenRangesHelp (swap r1) (swap r2)
rY = endianCondRange r2 rYY rYN
rN = endianCondRange r2 rNY rNN
r = endianCondRange r1 rY rN
rs' = r : (tail $ tail rs)
flattenRangesHelp :: Range -> Range -> Range
flattenRangesHelp (s1, e1) (s2, e2) =
(simplify upper, simplify lower)
where
size1 = rangeSize (s1, e1)
size2 = rangeSize (s2, e2)
lower = BinOp Add e2 (BinOp Mul e1 size2)
upper = BinOp Add (BinOp Mul size1 size2) (BinOp Sub lower (Number "1"))
rewriteModuleItem :: Info -> ModuleItem -> ModuleItem
rewriteModuleItem info =
traverseLHSs (traverseNestedLHSs rewriteLHS ) .
traverseExprs (traverseNestedExprs rewriteExpr)
where
Info typeDims = info
dims :: Identifier -> (Range, Range)
dims x =
(dimInner, dimOuter)
where
(t, r) = typeDims Map.! x
dimInner = r
dimOuter = head $ snd $ typeRanges t
orientIdx :: Range -> Expr -> Expr
orientIdx r e =
endianCondExpr r e eSwapped
where
eSwapped = BinOp Sub (snd r) (BinOp Sub e (fst r))
rewriteExpr :: Expr -> Expr
rewriteExpr (Ident x) =
if head x == ':'
then Ident $ tail x
else Ident x
rewriteExpr (orig @ (Bit (Bit (Ident x) idxInner) idxOuter)) =
if Map.member x typeDims
then Bit (Ident x') idx'
else orig
where
(dimInner, dimOuter) = dims x
x' = ':' : x
idxInner' = orientIdx dimInner idxInner
idxOuter' = orientIdx dimOuter idxOuter
base = BinOp Mul idxInner' (rangeSize dimOuter)
idx' = simplify $ BinOp Add base idxOuter'
rewriteExpr (orig @ (Bit (Ident x) idx)) =
if Map.member x typeDims
then Range (Ident x') mode' range'
else orig
where
(dimInner, dimOuter) = dims x
x' = ':' : x
mode' = IndexedPlus
idx' = orientIdx dimInner idx
len = rangeSize dimOuter
base = BinOp Add (endianCondExpr dimOuter (snd dimOuter) (fst dimOuter)) (BinOp Mul idx' len)
range' = (simplify base, simplify len)
rewriteExpr (orig @ (Range (Ident x) mode range)) =
if Map.member x typeDims
then Range (Ident x') mode' range'
else orig
where
(_, dimOuter) = dims x
x' = ':' : x
mode' = mode
size = rangeSize dimOuter
base = endianCondExpr dimOuter (snd dimOuter) (fst dimOuter)
range' =
case mode of
NonIndexed ->
(simplify hi, simplify lo)
where
lo = BinOp Mul size (snd range)
hi = BinOp Sub (BinOp Add lo (BinOp Mul (rangeSize range) size)) (Number "1")
IndexedPlus -> (BinOp Add (BinOp Mul size (fst range)) base, BinOp Mul size (snd range))
IndexedMinus -> (BinOp Add (BinOp Mul size (fst range)) base, BinOp Mul size (snd range))
rewriteExpr (orig @ (Range (Bit (Ident x) idxInner) modeOuter rangeOuter)) =
if Map.member x typeDims
then Range (Ident x') mode' range'
else orig
where
(dimInner, dimOuter) = dims x
x' = ':' : x
mode' = IndexedPlus
idxInner' = orientIdx dimInner idxInner
rangeOuterReverseIndexed =
(BinOp Add (fst rangeOuter) (BinOp Sub (snd rangeOuter)
(Number "1")), snd rangeOuter)
(baseOuter, lenOuter) =
case modeOuter of
IndexedPlus ->
endianCondRange dimOuter rangeOuter rangeOuterReverseIndexed
IndexedMinus ->
endianCondRange dimOuter rangeOuterReverseIndexed rangeOuter
NonIndexed ->
(endianCondExpr dimOuter (snd rangeOuter) (fst rangeOuter), rangeSize rangeOuter)
idxOuter' = orientIdx dimOuter baseOuter
start = BinOp Mul idxInner' (rangeSize dimOuter)
base = simplify $ BinOp Add start idxOuter'
len = lenOuter
range' = (base, len)
rewriteExpr other = other
rewriteLHS :: LHS -> LHS
rewriteLHS (LHSIdent x) =
LHSIdent x'
where Ident x' = rewriteExpr (Ident x)
rewriteLHS (orig @ (LHSBit (LHSBit (LHSIdent x) idxInner) idxOuter)) =
if Map.member x typeDims
then LHSBit (LHSIdent x') idx'
else orig
where Bit (Ident x') idx' =
rewriteExpr (Bit (Bit (Ident x) idxInner) idxOuter)
rewriteLHS (orig @ (LHSBit (LHSRange (LHSIdent x) modeInner rangeInner) idxOuter)) =
if Map.member x typeDims
then LHSRange (LHSIdent x') mode' range'
else orig
where Range (Ident x') mode' range' =
rewriteExpr (Bit (Range (Ident x) modeInner rangeInner) idxOuter)
rewriteLHS (orig @ (LHSBit (LHSIdent x) idx)) =
if Map.member x typeDims
then LHSRange (LHSIdent x') mode' range'
else orig
where Range (Ident x') mode' range' = rewriteExpr (Bit (Ident x) idx)
rewriteLHS (orig @ (LHSRange (LHSIdent x) mode range)) =
if Map.member x typeDims
then LHSRange (LHSIdent x') mode' range'
else orig
where Range (Ident x') mode' range' =
rewriteExpr (Range (Ident x) mode range)
rewriteLHS (orig @ (LHSRange (LHSBit (LHSIdent x) idxInner) modeOuter rangeOuter)) =
if Map.member x typeDims
then LHSRange (LHSIdent x') mode' range'
else orig
where Range (Ident x') mode' range' =
rewriteExpr (Range (Bit (Ident x) idxInner) modeOuter rangeOuter)
rewriteLHS other = other