/* $Id: qpforeign.pl,v 1.4 2004/09/30 10:41:35 jan Exp $ Part of SWI-Prolog Author: Jan Wielemaker E-mail: jan@swi.psy.uva.nl WWW: http://www.swi-prolog.org Copyright (C): 1985-2002, University of Amsterdam This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module(qp_foreign, [ load_foreign_files/0, % load_foreign_files/2, % +Files, +Libs load_foreign_files/3, % +Object, +Files, +Libs make_shared_object/3, % +Object, +Files, +Libs make_foreign_wrapper_file/1, % +OutBase make_foreign_wrapper_file/2 % +OFiles, +OutBase ]). :- use_module(shlib). :- use_module(gensym). /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - This module defines a Quintus compatible foreign language interface based on the foreign_file/2 and foreign/3 declarations. Predicates: # load_foreign_files/0 Load all foreign files defined with foreign_file/2 statement in the current module. # load_foreign_files(+Files, +Libs) Load specified foreign files, linking them with the given libraries # load_foreign_files(+SharedObject, +Files, +Libs) As load_foreign_files/2, but first tries to load `SharedObject'. If the SharedObject exists it is loaded using load_foreign_library/1. Otherwise it is first created with make_shared_object/3. # make_shared_object(+SharedObject, +Files, +Libs) Generate a wrapper and link it using plld to the given SharedObject. # make_foreign_wrapper_file(+Files, +OutBase) Generate wrapper for the named object files in OutBase.c. # make_foreign_wrapper_file(+Files) Generate wrapper for all declared object files in OutBase.c. Example: foreign_file('-lm', [sin/2]). foreign(sin, c, sin(+float, [-float])). :- load_foreign_files, abolish(foreign_file, 2), abolish(foreign, 3). Supported types: ============================================================= Spec Prolog C ============================================================= integer integer long float float|integer double single float|integer single string atom|string char * atom atom atom identifier (type atomic) ============================================================= NOTE: This modules requires a correctly functioning plld and load_foreign_library/1 on your system. If this isn't the case use make_foreign_wrapper_file/[1,2] to generate a wrapper and use static embedding. NOTE: The generated linkN.c file may also be used for creating a statically linked executable as described in pl-extend.c BUGS: * Only supports C-interface * Insufficient checking for misusage. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ :- module_transparent load_foreign_files/0, load_foreign_files/2, load_foreign_files/3, make_shared_object/3, make_C_prototype/2, make_C_init/3, make_wrappers/2, make_wrapper/2, get_foreign_head/3, make_foreign_wrapper_file/1, make_foreign_wrapper_file/2, collect_foreign_predicates/2. % make_wrapper(+Stream, +PrologHead) % % Generates a C-wrapper function for the given foreign defined % Prolog predicate. The wrapper is called _plw_. make_wrappers([], _). make_wrappers([H|T], Out) :- make_wrapper(Out, H), make_wrappers(T, Out). make_wrapper(Out, Spec) :- get_foreign_head(Spec, Func, Head), ( check_head(Head) -> functor(Head, _Name, ArgN), wrapper_name(Head, WrapName), make_C_header(Out, WrapName, ArgN), make_C_decls(Out, Head), make_C_prototype(Out, Head), make_C_input_conversions(Out, Head), make_C_call(Out, Head, Func), make_C_output_conversions(Out, Head), make_C_footer(Out) ; fail ). % get_foreign_head(+Spec, -Func, -Head) % % Get 3rd argument of relevant foreign/3 clause. get_foreign_head(Spec, Func, Head) :- ( atom(Spec), call(foreign(Func, c, Head)), functor(Head, Spec, _) -> true ; Spec = Name/Arity -> functor(Head, Name, Arity), call(foreign(Func, c, Head)) ; Head = Spec, call(foreign(Func, c, Head)) ). check_head(Head) :- functor(Head, _, Arity), ( arg(N, Head, [-T]), \+ valid_type(T) -> warning('Bad return type ~w in ~w', [T, Head]), fail ; arg(N, Head, [-T]), N \== Arity -> warning('Return type must be last in ~w', Head), fail ; (arg(_, Head, -T) ; arg(_, Head, +T)), \+ valid_type(T) -> warning('Bad type ~w in ~w', [T, Head]), fail ; true ). valid_type(integer). valid_type(float). valid_type(single). valid_type(string). valid_type(atom). % make_C_header(+Stream, +WrapperName, +Arity) % % Write function-header for the wrapper. This is easy as the % the return-type is always foreign_t and the arguments are % always of type `term_t'. The arguments are simply named `a', % `b', ... make_C_header(Out, WrapName, ArgN) :- format(Out, '~n~nstatic foreign_t~n~w(', [WrapName]), forall(between(1, ArgN, A), ( (A \== 1 -> format(Out, ', ', []) ; true) , arg_name(A, AName), format(Out, 'term_t ~w', [AName]) )), format(Out, ')~n{ ', []). % make_C_decls(+Stream, +PrologHead) % % Writes the C variable declarations. If the return value is % used a variable named `rval' is created. For each input parameter % a C variable named i is created; for each output variable % o. make_C_decls(Out, Head) :- arg(_, Head, [-PlType]), map_C_type(PlType, CType), format(Out, '~wrval;~n ', [CType]), fail. make_C_decls(Out, Head) :- arg(N, Head, -PlType), map_C_type(PlType, CType), arg_name(N, AName), format(Out, '~wo~w;~n ', [CType, AName]), fail. make_C_decls(Out, Head) :- arg(N, Head, +PlType), map_C_type(PlType, CType), arg_name(N, AName), format(Out, '~wi~w;~n ', [CType, AName]), fail. make_C_decls(Out, _) :- format(Out, '~n', []). % make_C_prototype(+Stream, +PrologHead) % % If the function handles floats or doubles, make a prototype % declaration for it to avoid unwanted conversions. make_C_prototype(Out, Head) :- % arg(_, Head, A), % ( term_member(float, A) % ; term_member(single, A) % ), !, ( arg(_, Head, [-Type]) -> map_C_type(Type, CType) ; CType = '' ), copy_term(Head, H2), % don't bind Head call(foreign(CFunc, c, H2)), format(Out, ' extern ~w~w(', [CType, CFunc]), ( arg(N, Head, AType), ( AType = +T2 -> (N > 1 -> format(Out, ', ', []) ; true), map_C_type(T2, CT2), format(Out, '~w', [CT2]) ; AType = -T2 -> (N > 1 -> format(Out, ', ', []) ; true), map_C_type(T2, CT2), format(Out, '~w *', [CT2]) ), fail ; format(Out, ');~n~n', []) ). make_C_prototype(_, _). term_member(A, A). term_member(A, B) :- arg(_, B, C), term_member(A, C). % make_C_input_conversions(+Stream, +PrologHead) % % Generate the input checking and conversion code. Assumes % boolean functions that take a Prolog term_t as first argument % and a pointer to the requested C-type as a second argument. % Function returns 0 if the conversion fails. make_C_input_conversions(Out, Head) :- findall(N-T, arg(N, Head, +T), IArgs), ( IArgs == [] -> true ; format(Out, ' if ( ', []), ( member(N-T, IArgs), (IArgs \= [N-T|_] -> format(Out, ' ||~n ', []) ; true), arg_name(N, AName), atom_concat(i, AName, IName), format(Out, '!PL_cvt_i_~w(~w, &~w)', [T, AName, IName]), fail ; true ), format(Out, ' )~n return FALSE;~n~n', []) ). % make_C_call(+Stream, +Prolog, +CFunction) % % Generate the actual call to the foreign function. Input variables % may be handed directly; output variables as a pointer to the o. make_C_call(Out, Head, CFunc) :- ( arg(_, Head, [-_]) -> format(Out, ' rval = ~w(', [CFunc]) ; format(Out, ' (void) ~w(', [CFunc]) ), arg(N, Head, Arg), Arg \= [_], (N \== 1 -> format(Out, ', ', []) ; true), arg_name(N, AName), ( Arg = -_ -> format(Out, '&o~w', [AName]) ; format(Out, 'i~w', [AName]) ), fail. make_C_call(Out, _, _) :- format(Out, ');~n', []). % make_C_output_conversions(+Stream, +PrologHead) % % Generate conversions for the output arguments and unify them % with the Prolog term_t arguments. make_C_output_conversions(Out, Head) :- findall(N-T, arg(N, Head, -T), OArgs0), ( arg(_, Head, [-T]) -> OArgs = [rval-T|OArgs0] ; OArgs = OArgs0 ), ( OArgs == [] -> true ; format(Out, '~n if ( ', []), ( member(N-T, OArgs), ( N == rval -> OName = rval, arg(RN, Head, [-_]), arg_name(RN, AName) ; arg_name(N, AName), atom_concat(o, AName, OName) ), (OArgs = [N-T|_] -> true ; format(Out, ' ||~n ', [])), format(Out, '!PL_cvt_o_~w(~w, ~w)', [T, OName, AName]), fail ; true ), format(Out, ' )~n return FALSE;~n', []) ). make_C_footer(Out) :- format(Out, '~n return TRUE;~n}~n', []). /******************************* * INIT STATEMENT * *******************************/ % make_C_init(+Stream, +PredList) % % Generate an array of PL_extension structures, that may be used to % create a statically linked image as well as through the % PL_load_extensions() call. % % Of the supported PL_FA_, TRANSPARENT may be declared by looking % at the transparent (meta_predivate) attribute of the predicate. make_C_init(Out, InstallFunc, Preds) :- format(Out, '~n~nstatic PL_extension predicates [] =~n{~n', []), format(Out, '/*{ "name", arity, function, PL_FA_ },*/~n', []), ( member(Pred, Preds), get_foreign_head(Pred, _Func, Head), functor(Head, Name, Arity), wrapper_name(Head, Wrapper), strip_module(Head, M, H), foreign_attributes(M:H, Atts), format(Out, ' { "~w", ~d, ~w, ~w },~n', [Name, Arity, Wrapper, Atts]), fail ; true ), format(Out, ' { NULL, 0, NULL, 0 } /* terminator */~n};~n~n', []), format(Out, 'install_t~n~w()~n{ PL_load_extensions(predicates);~n', [InstallFunc]), format(Out, '}~n', []). foreign_attributes(Head, Atts) :- findall(A, foreign_attribute(Head, A), A0), concat_atom(A0, '|', Atts). insert_separator([], _, []). insert_separator([H], _, [H]). insert_separator([A|T], S, [A, S|NT]) :- insert_separator(T, S, NT). foreign_attribute(Head, 'PL_FA_TRANSPARENT') :- predicate_property(Head, transparent). % make_C_file_header(+Stream) % % Output the generic header declarations needed and some comments make_C_file_header(Out) :- current_prolog_flag(version, Version), get_time(Time), convert_time(Time, Y, M, D, H, Min, _, _), format(Out, '/* SWI-Prolog link wrapper~n', []), format(Out, ' Generated by SWI-Prolog version ~w~n', [Version]), format(Out, ' At ~w/~w/~w ~w:~w~n', [D, M, Y, H, Min]), ( source_location(File, Line) -> format(Out, ' Source context ~w:~d~n', [File, Line]) ; true ), format(Out, '*/~n~n', []), format(Out, '#include ~n', []), format(Out, '#ifndef NULL~n', []), format(Out, '#define NULL ((void *)0)~n', []), format(Out, '#endif~n~n', []). /******************************* * TOPLEVEL * *******************************/ % Calls make_foreign_wrapper_file(+File), compiles the wrapper % and loads the predicates. load_foreign_files :- findall(File, foreign_file(File, _), OFiles), load_foreign_files(OFiles, []). load_foreign_files(OFiles, Libs) :- gensym(link, LinkBase), load_foreign_files(LinkBase, OFiles, Libs). load_foreign_files(LinkBase, _, _) :- catch(load_foreign_library(LinkBase), _, fail), !. load_foreign_files(LinkBase, OFiles, Libs) :- make_shared_object(LinkBase, OFiles, Libs), load_foreign_library(LinkBase). make_shared_object(LinkBase, OFiles, Libs) :- make_foreign_wrapper_file(OFiles, LinkBase), file_name_extension(LinkBase, c, CFile), build_shared_object(LinkBase, [CFile|OFiles], Libs). % Just output the wrapper file to the named .c file. May be used % to prepare for static linking or the preparation of the native % SWI-Prolog foreign-file. make_foreign_wrapper_file(CFile) :- findall(File, foreign_file(File, _), OFiles), make_foreign_wrapper_file(OFiles, CFile). make_foreign_wrapper_file(OFiles, Base) :- file_name_extension(Base, c, CFile), atom_concat(install_, Base, InstallFunc), collect_foreign_predicates(OFiles, Preds), open(CFile, write, Out), make_C_file_header(Out), make_wrappers(Preds, Out), make_C_init(Out, InstallFunc, Preds), close(Out). collect_foreign_predicates([], []). collect_foreign_predicates([File|Files], Preds) :- call(foreign_file(File, P0)), collect_foreign_predicates(Files, P1), append(P0, P1, Preds). build_shared_object(Object, Files, Libs) :- current_prolog_flag(shared_object_extension, Ext), file_name_extension(Object, Ext, SharedObject), append(Files, Libs, Input), concat_atom(Input, ' ', InputAtom), sformat(Command, 'plld -shared -o ~w ~w', [SharedObject, InputAtom]), shell(Command). /******************************* * UTIL * *******************************/ arg_name(N, Name) :- C is N + 0'a - 1, name(Name, [C]). wrapper_name(Head, Wrapper) :- functor(Head, Name, Arity), concat_atom(['_plw_', Name, Arity], Wrapper). % map_C_type(+Prolog, -C) % % Map Prolog interface type declarations into C types. map_C_type(X, Y) :- map_C_type_(X, Y), !. map_C_type(X, X). map_C_type_(integer, 'long '). map_C_type_(float, 'double '). map_C_type_(string, 'char *'). warning(Fmt, Args) :- print_message(warning, format(Fmt, Args)).