Replace use of "Strict" typeclass by use of deepseq library

.gitlab-ci.yml

@@ -3,4 +3,4 @@ build:
   tags:
     - "x86_64-linux"
   script:
-    - "cabal build -w $GHC"
+    - "cabal update && cabal build -w $GHC"

hpc-bin.cabal

@@ -42,11 +42,12 @@ library
     autogen-modules: Paths_hpc_bin
 
     build-depends: base       >= 4   && < 5,
+                   deepseq    >= 1.4.7 && < 1.5,
                    directory  >= 1   && < 1.4,
                    filepath   >= 1   && < 1.5,
                    containers >= 0.1 && < 0.7,
                    array      >= 0.1 && < 0.6,
-                   hpc        >= 0.6.1 && < 0.7
+                   hpc        >= 0.6.2 && < 0.7
 
     if flag(build-tool-depends)
       build-tool-depends: happy:happy >= 1.20.0

src/HpcCombine.hs

@@ -10,7 +10,8 @@ import Trace.Hpc.Util
 
 import HpcFlags
 
-import Control.Monad
+import Control.DeepSeq ( force )
+import Control.Monad ( foldM )
 import qualified Data.Set as Set
 import qualified Data.Map as Map
 
@@ -125,7 +126,7 @@ map_main _     _  = hpcError map_plugin $ "to many .tix files specified"
 mergeTixFile :: Flags -> (Integer -> Integer -> Integer) -> Tix -> String -> IO Tix
 mergeTixFile flags fn tix file_name = do
   Just new_tix <- readTix file_name
-  return $! strict $ mergeTix (mergeModule flags) fn tix (filterTix flags new_tix)
+  return $! force $ mergeTix (mergeModule flags) fn tix (filterTix flags new_tix)
 
 -- could allow different numbering on the module info,
 -- as long as the total is the same; will require normalization.
@@ -162,36 +163,3 @@ mergeTix modComb f
    fm2 = Map.fromList [ (tixModuleName tix,tix)
                       | tix <- t2
                       ]
-
-
--- What I would give for a hyperstrict :-)
--- This makes things about 100 times faster.
-class Strict a where
-   strict :: a -> a
-
-instance Strict Integer where
-   strict i = i
-
-instance Strict Int where
-   strict i = i
-
-instance Strict Hash where      -- should be fine, because Hash is a newtype round an Int
-   strict i = i
-
-instance Strict Char where
-   strict i = i
-
-instance Strict a => Strict [a] where
-   strict (a:as) = (((:) $! strict a) $! strict as)
-   strict []     = []
-
-instance (Strict a, Strict b) => Strict (a,b) where
-   strict (a,b) = (((,) $! strict a) $! strict b)
-
-instance Strict Tix where
-  strict (Tix t1) =
-            Tix $! strict t1
-
-instance Strict TixModule where
-  strict (TixModule m1 p1 i1 t1) =
-            ((((TixModule $! strict m1) $! strict p1) $! strict i1) $! strict t1)