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%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[CgConTbls]{Info tables and update bits for constructors}
\begin{code}
module CgConTbls ( genStaticConBits ) where
#include "HsVersions.h"
import AbsCSyn
import CgMonad
import AbsCUtils ( mkAbstractCs, mkAbsCStmts )
import CgTailCall ( performReturn, mkStaticAlgReturnCode )
import ClosureInfo ( layOutStaticClosure, layOutDynCon,
mkConLFInfo, ClosureInfo
)
import DataCon ( DataCon, dataConName, dataConRepArgTys, isNullaryDataCon )
import Name ( getOccName )
import OccName ( occNameUserString )
import TyCon ( tyConDataCons, isEnumerationTyCon, TyCon )
import Type ( typePrimRep )
\end{code}
For every constructor we generate the following info tables:
A static info table, for static instances of the constructor,
Plus:
\begin{tabular}{lll}
Info tbls & Macro & Kind of constructor \\
\hline
info & @CONST_INFO_TABLE@& Zero arity (no info -- compiler uses static closure)\\
info & @CHARLIKE_INFO_TABLE@& Charlike (no info -- compiler indexes fixed array)\\
info & @INTLIKE_INFO_TABLE@& Intlike; the one macro generates both info tbls\\
info & @SPEC_INFO_TABLE@& SPECish, and bigger than or equal to @MIN_UPD_SIZE@\\
info & @GEN_INFO_TABLE@& GENish (hence bigger than or equal to @MIN_UPD_SIZE@)\\
\end{tabular}
Possible info tables for constructor con:
\begin{description}
\item[@_con_info@:]
Used for dynamically let(rec)-bound occurrences of
the constructor, and for updates. For constructors
which are int-like, char-like or nullary, when GC occurs,
the closure tries to get rid of itself.
\item[@_static_info@:]
Static occurrences of the constructor
macro: @STATIC_INFO_TABLE@.
\end{description}
For zero-arity constructors, \tr{con}, we NO LONGER generate a static closure;
it's place is taken by the top level defn of the constructor.
For charlike and intlike closures there is a fixed array of static
closures predeclared.
\begin{code}
genStaticConBits :: CompilationInfo -- global info about the compilation
-> [TyCon] -- tycons to generate
-> AbstractC -- output
genStaticConBits comp_info gen_tycons
= -- for each type constructor:
-- grab all its data constructors;
-- for each one, generate an info table
-- for each specialised type constructor
-- for each specialisation of the type constructor
-- grab data constructors, and generate info tables
-- ToDo: for tycons and specialisations which are not
-- declared in this module we must ensure that the
-- C labels are local to this module i.e. static
-- since they may be duplicated in other modules
mkAbstractCs [ gen_for_tycon tc | tc <- gen_tycons ]
where
gen_for_tycon :: TyCon -> AbstractC
gen_for_tycon tycon
= mkAbstractCs (map (genConInfo comp_info tycon) (tyConDataCons tycon))
`mkAbsCStmts` (
-- after the con decls, so we don't need to declare the constructor labels
if (isEnumerationTyCon tycon)
then CClosureTbl tycon
else AbsCNop
)
\end{code}
%************************************************************************
%* *
\subsection[CgConTbls-info-tables]{Generating info tables for constructors}
%* *
%************************************************************************
Generate the entry code, info tables, and (for niladic constructor) the
static closure, for a constructor.
\begin{code}
genConInfo :: CompilationInfo -> TyCon -> DataCon -> AbstractC
genConInfo comp_info tycon data_con
= mkAbstractCs [
CSplitMarker,
closure_code,
static_code]
-- Order of things is to reduce forward references
where
(closure_info, body_code) = mkConCodeAndInfo data_con
-- To allow the debuggers, interpreters, etc to cope with static
-- data structures (ie those built at compile time), we take care that
-- info-table contains the information we need.
(static_ci,_) = layOutStaticClosure con_name typePrimRep arg_tys
(mkConLFInfo data_con)
body = (initC comp_info (
profCtrC SLIT("TICK_ENT_CON") [CReg node] `thenC`
body_code))
con_descr = occNameUserString (getOccName data_con)
-- Don't need any dynamic closure code for zero-arity constructors
closure_code = if zero_arity_con then
AbsCNop
else
CClosureInfoAndCode closure_info body Nothing con_descr
static_code = CClosureInfoAndCode static_ci body Nothing con_descr
zero_arity_con = isNullaryDataCon data_con
-- We used to check that all the arg-sizes were zero, but we don't
-- really have any constructors with only zero-size args, and it's
-- just one more thing to go wrong.
arg_tys = dataConRepArgTys data_con
con_name = dataConName data_con
\end{code}
\begin{code}
mkConCodeAndInfo :: DataCon -- Data constructor
-> (ClosureInfo, Code) -- The info table
mkConCodeAndInfo con
= let
arg_tys = dataConRepArgTys con
(closure_info, arg_things)
= layOutDynCon con typePrimRep arg_tys
body_code
= -- NB: We don't set CC when entering data (WDP 94/06)
profCtrC SLIT("TICK_RET_OLD")
[mkIntCLit (length arg_things)] `thenC`
performReturn AbsCNop -- Ptr to thing already in Node
(mkStaticAlgReturnCode con)
in
(closure_info, body_code)
\end{code}
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