X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FLiteral.lhs;h=da8685e6b3f094ae51d141b6dbd787b9cba0b35a;hp=a03e1c14e03e539a5640cddbb6aba28bd4429a79;hb=c1c2c25355bc462e521b2c5fb41ac79307da22ff;hpb=f278f0676579f67075033a4f9857715909c4b71e

diff --git a/compiler/basicTypes/Literal.lhs b/compiler/basicTypes/Literal.lhs
index a03e1c1..da8685e 100644
--- a/compiler/basicTypes/Literal.lhs
+++ b/compiler/basicTypes/Literal.lhs
@@ -27,6 +27,7 @@ module Literal
 	-- ** Operations on Literals
 	, literalType
 	, hashLiteral
+        , absentLiteralOf
 
         -- ** Predicates on Literals and their contents
 	, litIsDupable, litIsTrivial
@@ -44,19 +45,21 @@ module Literal
 	) where
 
 import TysPrim
+import PrelNames
 import Type
+import TyCon
 import Outputable
 import FastTypes
 import FastString
 import BasicTypes
 import Binary
 import Constants
-
+import UniqFM
 import Data.Int
 import Data.Ratio
 import Data.Word
 import Data.Char
-import Data.Data
+import Data.Data( Data, Typeable )
 \end{code}
 
 
@@ -326,6 +329,21 @@ literalType (MachWord64  _) = word64PrimTy
 literalType (MachFloat _)   = floatPrimTy
 literalType (MachDouble _)  = doublePrimTy
 literalType (MachLabel _ _ _) = addrPrimTy
+
+absentLiteralOf :: TyCon -> Maybe Literal
+-- Return a literal of the appropriate primtive
+-- TyCon, to use as a placeholder when it doesn't matter
+absentLiteralOf tc = lookupUFM absent_lits (tyConName tc)
+
+absent_lits :: UniqFM Literal
+absent_lits = listToUFM [ (addrPrimTyConKey,    MachNullAddr)
+            		, (charPrimTyConKey,    MachChar 'x')
+            		, (intPrimTyConKey,     MachInt 0)
+            		, (int64PrimTyConKey,   MachInt64 0)
+            		, (floatPrimTyConKey,   MachFloat 0)
+            		, (doublePrimTyConKey,  MachDouble 0)
+            		, (wordPrimTyConKey,    MachWord 0)
+            		, (word64PrimTyConKey,  MachWord64 0) ]
 \end{code}