Add option to drop reg and wire from output

3 files changed, 74 insertions, 18 deletions

diff --git a/src/Verismith.hs b/src/Verismith.hs
index 578b7ac..c9d3e78 100644
--- a/src/Verismith.hs
+++ b/src/Verismith.hs
@@ -107,6 +107,8 @@ randomise config@(Config a _ c d e) = do
     ssc  <- return $ cs ^. probStmntCond
     ssf  <- return $ cs ^. probStmntFor
     en   <- return $ ce ^. probExprNum
+    keep_out <- return $ cmo ^. probModDropOutput
+    drop_out <- randDelete $ cmo ^. probModDropOutput
     ei   <- randDelete $ ce ^. probExprId
     ers  <- randDelete $ ce ^. probExprRangeSelect
     euo  <- randDelete $ ce ^. probExprUnOp
@@ -121,6 +123,7 @@ randomise config@(Config a _ c d e) = do
         (Probability (ProbModItem mia misa mica mii)
                      (ProbStatement ssb ssnb ssc ssf)
                      (ProbExpr en ei ers euo ebo ec eco estr esgn eus)
+                     (ProbMod drop_out keep_out)
         )
         c
         d
@@ -129,6 +132,7 @@ randomise config@(Config a _ c d e) = do
     cm = config ^. configProbability . probModItem
     cs = config ^. configProbability . probStmnt
     ce = config ^. configProbability . probExpr
+    cmo = config ^. configProbability . probMod
 
 handleOpts :: Opts -> IO ()
 handleOpts (Fuzz o configF f k n nosim noequiv noreduction file top cc checker) = do
diff --git a/src/Verismith/Config.hs b/src/Verismith/Config.hs
index 2c239d7..f757ebb 100644
--- a/src/Verismith/Config.hs
+++ b/src/Verismith/Config.hs
@@ -25,6 +25,8 @@ module Verismith.Config
     , ProbModItem(..)
     -- *** Statement
     , ProbStatement(..)
+    -- *** Module
+    , ProbMod (..)
     -- ** ConfProperty
     , ConfProperty(..)
     -- ** Simulator Description
@@ -42,6 +44,9 @@ module Verismith.Config
     , configSimulators
     , configSynthesisers
     , probModItem
+    , probMod
+    , probModDropOutput
+    , probModKeepOutput
     , probStmnt
     , probExpr
     , probExprNum
@@ -199,6 +204,14 @@ data ProbStatement = ProbStatement { _probStmntBlock    :: {-# UNPACK #-} !Int
                                    }
                    deriving (Eq, Show)
 
+-- | Probability of generating various properties of a module.
+data ProbMod = ProbMod { _probModDropOutput :: {-# UNPACK #-} !Int
+                       -- ^ "@module.drop_output@: frequency of a wire or register being dropped from the output."
+                       , _probModKeepOutput :: {-# UNPACK #-} !Int
+                       -- ^ "@module.keep_output@: frequency of a wire or register being kept in the output."
+                       }
+             deriving (Eq, Show)
+
 -- | @[probability]@: combined probabilities.
 data Probability = Probability { _probModItem :: {-# UNPACK #-} !ProbModItem
                                -- ^ Probabilities for module items.
@@ -206,6 +219,7 @@ data Probability = Probability { _probModItem :: {-# UNPACK #-} !ProbModItem
                                -- ^ Probabilities for statements.
                                , _probExpr    :: {-# UNPACK #-} !ProbExpr
                                -- ^ Probaiblities for expressions.
+                               , _probMod :: {-# UNPACK #-} !ProbMod
                                }
                  deriving (Eq, Show)
 
@@ -282,6 +296,7 @@ data Config = Config { _configInfo         :: Info
 $(makeLenses ''ProbExpr)
 $(makeLenses ''ProbModItem)
 $(makeLenses ''ProbStatement)
+$(makeLenses ''ProbMod)
 $(makeLenses ''Probability)
 $(makeLenses ''ConfProperty)
 $(makeLenses ''Info)
@@ -325,32 +340,35 @@ fromQuartusLight (QuartusLight a b c) = SynthDescription "quartuslight"
 defaultConfig :: Config
 defaultConfig = Config
     (Info (pack $(gitHash)) (pack $ showVersion version))
-    (Probability defModItem defStmnt defExpr)
+    (Probability defModItem defStmnt defExpr defMod)
     (ConfProperty 20 Nothing 3 2 5 "random" 10 False 0 1 Nothing)
     []
     [fromYosys defaultYosys, fromVivado defaultVivado]
   where
+    defMod =
+      ProbMod 0 -- Drop Output
+              1 -- Keep Output
     defModItem =
         ProbModItem 5 -- Assign
-                      1 -- Sequential Always
-                        1 -- Combinational Always
-                          1 -- Instantiation
+                    1 -- Sequential Always
+                    1 -- Combinational Always
+                    1 -- Instantiation
     defStmnt =
         ProbStatement 0 -- Blocking assignment
-                        3 -- Non-blocking assignment
-                          1 -- Conditional
-                            0 -- For loop
+                      3 -- Non-blocking assignment
+                      1 -- Conditional
+                      0 -- For loop
     defExpr =
         ProbExpr 1 -- Number
-                   5 -- Identifier
-                     5 -- Range selection
-                       5 -- Unary operator
-                         5 -- Binary operator
-                           5 -- Ternary conditional
-                             3 -- Concatenation
-                               0 -- String
-                                 5 -- Signed function
-                                   5 -- Unsigned funtion
+                 5 -- Identifier
+                 5 -- Range selection
+                 5 -- Unary operator
+                 5 -- Binary operator
+                 5 -- Ternary conditional
+                 3 -- Concatenation
+                 0 -- String
+                 5 -- Signed function
+                 5 -- Unsigned funtion
 
 twoKey :: Toml.Piece -> Toml.Piece -> Toml.Key
 twoKey a b = Toml.Key (a :| [b])
@@ -415,6 +433,16 @@ modItemCodec =
     defProb i = defaultConfig ^. configProbability . probModItem . i
     intM = int "moditem"
 
+modCodec :: TomlCodec ProbMod
+modCodec =
+  ProbMod <$> defaultValue (defProb probModDropOutput) (intM "drop_output")
+          .=  _probModDropOutput
+          <*> defaultValue (defProb probModKeepOutput) (intM "keep_output")
+          .=  _probModKeepOutput
+  where
+    defProb i = defaultConfig ^. configProbability . probMod . i
+    intM = int "module"
+
 probCodec :: TomlCodec Probability
 probCodec =
     Probability
@@ -424,6 +452,8 @@ probCodec =
         .=  _probStmnt
         <*> defaultValue (defProb probExpr) exprCodec
         .=  _probExpr
+        <*> defaultValue (defProb probMod) modCodec
+        .= _probMod
     where defProb i = defaultConfig ^. configProbability . i
 
 propCodec :: TomlCodec ConfProperty
diff --git a/src/Verismith/Generate.hs b/src/Verismith/Generate.hs
index 4d51d21..52baf0d 100644
--- a/src/Verismith/Generate.hs
+++ b/src/Verismith/Generate.hs
@@ -562,6 +562,26 @@ calcRange ps i (Range l r) = eval l - eval r + 1
 identElem :: Port -> [Port] -> Bool
 identElem p = elem (p ^. portName) . toListOf (traverse . portName)
 
+-- | Select items from a list with a specific frequency, returning the new list
+-- that contains the selected items. If 0 is passed to both the select and
+-- not-select parameter, the function will act like the idententy, returning the
+-- original list inside the 'Gen' monad.
+--
+-- The reason for doing this at the output of a module reduces the number of
+-- wires that are exposed at the output and therefore allows the synthesis tool
+-- to perform more optimisations that it could otherwise not perform. The
+-- synthesis tool is quite strict with optimisations if all the wires and
+-- registers are exposed.
+selectwfreq :: (MonadGen m) => Int -> Int -> [a] -> m [a]
+selectwfreq _ _ [] = return []
+selectwfreq s n a@(l:ls)
+  | s > 0 && n > 0 =
+      Hog.frequency
+      [ (s, (l:) <$> selectwfreq s n ls)
+      , (n, selectwfreq s n ls)
+      ]
+  | otherwise = return a
+
 -- | Generates a module definition randomly. It always has one output port which
 -- is set to @y@. The size of @y@ is the total combination of all the locally
 -- defined wires, so that it correctly reflects the internal state of the
@@ -582,11 +602,13 @@ moduleDef top = do
                 $   local
                 ^.. traverse
                 .   portSize
-    let combine = config ^. configProperty . propCombine
+    let (ProbMod n s) = config ^. configProbability . probMod
+    newlocal <- selectwfreq s n local
     let clock   = Port Wire False 1 "clk"
+    let combine = config ^. configProperty . propCombine
     let yport =
             if combine then Port Wire False 1 "y" else Port Wire False size "y"
-    let comb = combineAssigns_ combine yport local
+    let comb = combineAssigns_ combine yport newlocal
     return
         . declareMod local
         . ModDecl name [yport] (clock : newPorts) (comb : mi)