--
-----------------------------------------------------------------------------
-
module StgCmmClosure (
SMRep,
DynTag, tagForCon, isSmallFamily,
import StgSyn
import SMRep
-import Cmm ( ClosureTypeInfo(..), ConstrDescription )
+import CmmDecl ( ClosureTypeInfo(..), ConstrDescription )
import CmmExpr
import CLabel
{- Note [Data constructor dynamic tags]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The family size of a data type (the number of constructors)
-can be either:
+The family size of a data type (the number of constructors
+or the arity of a function) can be either:
* small, if the family size < 2**tag_bits
* big, otherwise.
Small families can have the constructor tag in the tag bits.
-Big families only use the tag value 1 to represent evaluatedness. -}
+Big families only use the tag value 1 to represent evaluatedness.
+We don't have very many tag bits: for example, we have 2 bits on
+x86-32 and 3 bits on x86-64. -}
isSmallFamily :: Int -> Bool
isSmallFamily fam_size = fam_size <= mAX_PTR_TAG