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|
{-|
Module : Test.VeriFuzz.Mutation
Description : Functions to mutate the Verilog AST.
Copyright : (c) Yann Herklotz Grave 2018
License : GPL-3
Maintainer : ymherklotz@gmail.com
Stability : experimental
Portability : POSIX
Functions to mutate the Verilog AST from "Test.VeriFuzz.VerilogAST" to generate
more random patterns, such as nesting wires instead of creating new ones.
-}
{-# LANGUAGE OverloadedStrings #-}
module Test.VeriFuzz.Mutate where
import Control.Lens
import Data.Maybe (catMaybes, fromMaybe)
import Test.VeriFuzz.Internal.Shared
import Test.VeriFuzz.VerilogAST
-- | Return if the 'Identifier' is in a 'ModuleDecl'.
inPort :: Identifier -> ModuleDecl -> Bool
inPort id mod = any (\a -> a ^. portName == id) $ mod ^. modPorts
-- | Find the last assignment of a specific wire/reg to an expression, and
-- returns that expression.
findAssign :: Identifier -> [ModuleItem] -> Maybe Expression
findAssign id items =
safe last . catMaybes $ isAssign <$> items
where
isAssign (Assign ca)
| ca ^. contAssignNetLVal == id = Just $ ca ^. contAssignExpr
| otherwise = Nothing
-- | Transforms an expression by replacing an Identifier with an
-- expression. This is used inside 'transformOf' and 'traverseExpr' to replace
-- the 'Identifier' recursively.
idTrans :: Identifier -> Expression -> Expression -> Expression
idTrans i expr (PrimExpr (PrimId id))
| id == i = expr
| otherwise = (PrimExpr (PrimId id))
idTrans _ _ e = e
-- | Replaces the identifier recursively in an expression.
replace :: Identifier -> Expression -> Expression -> Expression
replace = (transformOf traverseExpr .) . idTrans
-- | Nest expressions for a specific 'Identifier'. If the 'Identifier' is not found,
-- the AST is not changed.
--
-- This could be improved by instead of only using the last assignment to the
-- wire that one finds, to use the assignment to the wire before the current
-- expression. This would require a different approach though.
nestId :: Identifier -> ModuleDecl -> ModuleDecl
nestId id mod
| not $ inPort id mod =
let expr = fromMaybe def . findAssign id $ mod ^. moduleItems
in mod & get %~ replace id expr
| otherwise = mod
where
get = moduleItems . traverse . _Assign . contAssignExpr
def = PrimExpr $ PrimId id
-- | Replaces an identifier by a expression in all the module declaration.
nestSource :: Identifier -> SourceText -> SourceText
nestSource id src =
src & getSourceText . traverse . getDescription %~ nestId id
|
