Add (a) CoreM monad, (b) new Annotations feature

This patch, written by Max Bolingbroke,  does two things

1.  It adds a new CoreM monad (defined in simplCore/CoreMonad),
    which is used as the top-level monad for all the Core-to-Core
    transformations (starting at SimplCore).  It supports
       * I/O (for debug printing)
       * Unique supply
       * Statistics gathering
       * Access to the HscEnv, RuleBase, Annotations, Module
    The patch therefore refactors the top "skin" of every Core-to-Core
    pass, but does not change their functionality.

2.  It adds a completely new facility to GHC: Core "annotations".
    The idea is that you can say
       {#- ANN foo (Just "Hello") #-}
    which adds the annotation (Just "Hello") to the top level function
    foo.  These annotations can be looked up in any Core-to-Core pass,
    and are persisted into interface files.  (Hence a Core-to-Core pass
    can also query the annotations of imported things.)  Furthermore,
    a Core-to-Core pass can add new annotations (eg strictness info)
    of its own, which can be queried by importing modules.

The design of the annotation system is somewhat in flux.  It's
designed to work with the (upcoming) dynamic plug-ins mechanism,
but is meanwhile independently useful.

Do not merge to 6.10!  

1 files changed, 33 insertions, 2 deletions

diff --git a/compiler/iface/TcIface.lhs b/compiler/iface/TcIface.lhs
index 42dd3a8ac2..7f74cf2cd2 100644
--- a/compiler/iface/TcIface.lhs
+++ b/compiler/iface/TcIface.lhs
@@ -9,7 +9,7 @@ Type checking of type signatures in interface files
 module TcIface ( 
 	tcImportDecl, checkWiredInTyCon, tcHiBootIface, typecheckIface, 
 	tcIfaceDecl, tcIfaceInst, tcIfaceFamInst, tcIfaceRules,
-	tcIfaceVectInfo, tcIfaceGlobal, tcExtCoreBindings
+	tcIfaceVectInfo, tcIfaceAnnotations, tcIfaceGlobal, tcExtCoreBindings
  ) where
 
 #include "HsVersions.h"
@@ -22,6 +22,7 @@ import TcRnMonad
 import Type
 import TypeRep
 import HscTypes
+import Annotations
 import InstEnv
 import FamInstEnv
 import CoreSyn
@@ -201,10 +202,11 @@ typecheckIface iface
 	; let type_env = mkNameEnv names_w_things
 	; writeMutVar tc_env_var type_env
 
-		-- Now do those rules and instances
+		-- Now do those rules, instances and annotations
 	; insts     <- mapM tcIfaceInst    (mi_insts     iface)
 	; fam_insts <- mapM tcIfaceFamInst (mi_fam_insts iface)
 	; rules     <- tcIfaceRules ignore_prags (mi_rules iface)
+	; anns      <- tcIfaceAnnotations  (mi_anns iface)
 
                 -- Vectorisation information
         ; vect_info <- tcIfaceVectInfo (mi_module iface) type_env 
@@ -220,6 +222,7 @@ typecheckIface iface
 			      , md_insts     = insts
 			      , md_fam_insts = fam_insts
 			      , md_rules     = rules
+			      , md_anns      = anns
                               , md_vect_info = vect_info
 			      , md_exports   = exports
 			      }
@@ -614,6 +617,34 @@ tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bnd
 
 %************************************************************************
 %*									*
+		Annotations
+%*									*
+%************************************************************************
+
+\begin{code}
+tcIfaceAnnotations :: [IfaceAnnotation] -> IfL [Annotation]
+tcIfaceAnnotations = mapM tcIfaceAnnotation
+
+tcIfaceAnnotation :: IfaceAnnotation -> IfL Annotation
+tcIfaceAnnotation (IfaceAnnotation target serialized) = do
+    target' <- tcIfaceAnnTarget target
+    return $ Annotation {
+        ann_target = target',
+        ann_value = serialized
+    }
+
+tcIfaceAnnTarget :: IfaceAnnTarget -> IfL (AnnTarget Name)
+tcIfaceAnnTarget (NamedTarget occ) = do
+    name <- lookupIfaceTop occ
+    return $ NamedTarget name
+tcIfaceAnnTarget (ModuleTarget mod) = do
+    return $ ModuleTarget mod
+
+\end{code}
+
+
+%************************************************************************
+%*									*
 		Vectorisation information
 %*									*
 %************************************************************************