Monadify specialise/Specialise: use do, return, standard monad functions and MonadUnique

[ghc-hetmet.git] / compiler / specialise / Rules.lhs

diff --git a/compiler/specialise/Rules.lhs b/compiler/specialise/Rules.lhs
index fbdf925..090f0f0 100644 (file)
--- a/compiler/specialise/Rules.lhs
+++ b/compiler/specialise/Rules.lhs
@@ -4,11 +4,11 @@
 \section[CoreRules]{Transformation rules}
 
 \begin{code}
-{-# OPTIONS_GHC -w #-}
+{-# OPTIONS -w #-}
 -- The above warning supression flag is a temporary kludge.
 -- While working on this module you are encouraged to remove it and fix
 -- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
 -- for details
 
 module Rules (
@@ -35,8 +35,7 @@ import Type           ( Type, TvSubstEnv )
 import Coercion         ( coercionKind )
 import TcType          ( tcSplitTyConApp_maybe )
 import CoreTidy                ( tidyRules )
-import Id              ( Id, idUnfolding, isLocalId, isGlobalId, idName, idType,
-                         idSpecialisation, idCoreRules, setIdSpecialisation ) 
+import Id
 import IdInfo          ( SpecInfo( SpecInfo ) )
 import Var             ( Var )
 import VarEnv
@@ -225,15 +224,19 @@ lookupRule :: (Activation -> Bool) -> InScopeSet
           -> Id -> [CoreExpr] -> Maybe (CoreRule, CoreExpr)
 -- See Note [Extra argsin rule matching]
 lookupRule is_active in_scope rule_base fn args
-  = matchRules is_active in_scope fn args rules
-  where
+  = matchRules is_active in_scope fn args (getRules rule_base fn)
+
+getRules :: RuleBase -> Id -> [CoreRule]
        -- The rules for an Id come from two places:
        --      (a) the ones it is born with (idCoreRules fn)
        --      (b) rules added in subsequent modules (extra_rules)
        -- PrimOps, for example, are born with a bunch of rules under (a)
-    rules = extra_rules ++ idCoreRules fn
-    extra_rules | isLocalId fn = []
-               | otherwise    = lookupNameEnv rule_base (idName fn) `orElse` []
+getRules rule_base fn
+  | isLocalId fn  = idCoreRules fn
+  | otherwise     = WARN( not (isPrimOpId fn) && notNull (idCoreRules fn), 
+                         ppr fn <+> ppr (idCoreRules fn) )
+                   idCoreRules fn ++ (lookupNameEnv rule_base (idName fn) `orElse` [])
+       -- Only PrimOpIds have rules inside themselves, and perhaps more besides
 
 matchRules :: (Activation -> Bool) -> InScopeSet
           -> Id -> [CoreExpr]
@@ -595,11 +598,8 @@ match menv subst (Type ty1) (Type ty2)
   = match_ty menv subst ty1 ty2
 
 match menv subst (Cast e1 co1) (Cast e2 co2)
-  | (from1, to1) <- coercionKind co1
-  , (from2, to2) <- coercionKind co2
-  = do { subst1 <- match_ty menv subst  to1   to2
-       ; subst2 <- match_ty menv subst1 from1 from2
-       ; match menv subst2 e1 e2 }
+  = do { subst1 <- match_ty menv subst co1 co2
+       ; match menv subst1 e1 e2 }
 
 {-     REMOVING OLD CODE: I think that the above handling for let is 
                           better than the stuff here, which looks 
@@ -646,6 +646,8 @@ match_var menv subst@(tv_subst, id_subst, binds) v1 e2
 
                | otherwise     -- No renaming to do on e2, because no free var
                                -- of e2 is in the rnEnvR of the envt
+               -- Note [Matching variable types]
+               -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                -- However, we must match the *types*; e.g.
                --   forall (c::Char->Int) (x::Char). 
                --      f (c x) = "RULE FIRED"
@@ -766,16 +768,11 @@ is so important.
 We want to know what sites have rules that could have fired but didn't.
 This pass runs over the tree (without changing it) and reports such.
 
-NB: we assume that this follows a run of the simplifier, so every Id
-occurrence (including occurrences of imported Ids) is decorated with
-all its (active) rules.  No need to construct a rule base or anything
-like that.
-
 \begin{code}
-ruleCheckProgram :: CompilerPhase -> String -> [CoreBind] -> SDoc
+ruleCheckProgram :: CompilerPhase -> String -> RuleBase -> [CoreBind] -> SDoc
 -- Report partial matches for rules beginning 
 -- with the specified string
-ruleCheckProgram phase rule_pat binds 
+ruleCheckProgram phase rule_pat rule_base binds 
   | isEmptyBag results
   = text "Rule check results: no rule application sites"
   | otherwise
@@ -784,10 +781,10 @@ ruleCheckProgram phase rule_pat binds
          vcat [ p $$ line | p <- bagToList results ]
         ]
   where
-    results = unionManyBags (map (ruleCheckBind (phase, rule_pat)) binds)
+    results = unionManyBags (map (ruleCheckBind (phase, rule_pat, rule_base)) binds)
     line = text (replicate 20 '-')
          
-type RuleCheckEnv = (CompilerPhase, String)    -- Phase and Pattern
+type RuleCheckEnv = (CompilerPhase, String, RuleBase)  -- Phase and Pattern
 
 ruleCheckBind :: RuleCheckEnv -> CoreBind -> Bag SDoc
    -- The Bag returned has one SDoc for each call site found
@@ -816,11 +813,11 @@ ruleCheckFun :: RuleCheckEnv -> Id -> [CoreExpr] -> Bag SDoc
 -- Produce a report for all rules matching the predicate
 -- saying why it doesn't match the specified application
 
-ruleCheckFun (phase, pat) fn args
+ruleCheckFun (phase, pat, rule_base) fn args
   | null name_match_rules = emptyBag
   | otherwise            = unitBag (ruleAppCheck_help phase fn args name_match_rules)
   where
-    name_match_rules = filter match (idCoreRules fn)
+    name_match_rules = filter match (getRules rule_base fn)
     match rule = pat `isPrefixOf` unpackFS (ruleName rule)
 
 ruleAppCheck_help :: CompilerPhase -> Id -> [CoreExpr] -> [CoreRule] -> SDoc