{
    $Id$
    Copyright (c) 2002 by Florian Klaempfl

    Generic calling convention handling

    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 General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 ****************************************************************************
}
{# Parameter passing manager. Used to manage how
   parameters are passed to routines.
}
unit paramgr;

{$i fpcdefs.inc}

  interface

    uses
       cclasses,globtype,
       cpubase,cgbase,
       aasmtai,
       symconst,symtype,symdef;

    type
       {# This class defines some methods to take care of routine
          parameters. It should be overriden for each new processor
       }
       tparamanager = class
          {# Returns true if the return value is actually a parameter
             pointer.
          }
          function ret_in_param(def : tdef;calloption : tproccalloption) : boolean;virtual;

          function push_high_param(varspez:tvarspez;def : tdef;calloption : tproccalloption) : boolean;virtual;

          { Returns true if a parameter is too large to copy and only
            the address is pushed
          }
          function push_addr_param(varspez:tvarspez;def : tdef;calloption : tproccalloption) : boolean;virtual;
          { return the size of a push }
          function push_size(varspez:tvarspez;def : tdef;calloption : tproccalloption) : longint;
          { Returns true if a parameter needs to be copied on the stack, this
            is required for cdecl procedures
          }
          function copy_value_on_stack(varspez:tvarspez;def : tdef;calloption : tproccalloption) : boolean;virtual;
          {# Returns a structure giving the information on
            the storage of the parameter (which must be
            an integer parameter). This is only used when calling
            internal routines directly, where all parameters must
            be 4-byte values.

            In case the location is a register, this register is allocated.
            Call freeintparaloc() after the call to free the locations again.
            Default implementation: don't do anything at all (in case you don't
            use register parameter passing)

            @param(list Current assembler list)
            @param(nr Parameter number of routine, starting from 1)
          }
          function get_para_align(calloption : tproccalloption):byte;virtual;
          function get_volatile_registers_int(calloption : tproccalloption):tsuperregisterset;virtual;
          function get_volatile_registers_fpu(calloption : tproccalloption):tsuperregisterset;virtual;
          function getintparaloc(calloption : tproccalloption; nr : longint) : tparalocation;virtual;abstract;

          {# allocate a parameter location created with create_paraloc_info

            @param(list Current assembler list)
            @param(loc Parameter location)
          }
          procedure allocparaloc(list: taasmoutput; const loc: tparalocation); virtual;

          {# free a parameter location allocated with allocparaloc

            @param(list Current assembler list)
            @param(loc Parameter location)
          }
          procedure freeparaloc(list: taasmoutput; const loc: tparalocation); virtual;

          { This is used to populate the location information on all parameters
            for the routine as seen in either the caller or the callee. It returns
            the size allocated on the stack
          }
          function  create_paraloc_info(p : tabstractprocdef; side: tcallercallee):longint;virtual;abstract;

          { This is used to populate the location information on all parameters
            for the routine when it is being inlined. It returns
            the size allocated on the stack
          }
          function  create_inline_paraloc_info(p : tabstractprocdef):longint;virtual;

          { This is used to populate the location information on all parameters
            for the routine that are passed as varargs. It returns
            the size allocated on the stack (including the normal parameters)
          }
          function  create_varargs_paraloc_info(p : tabstractprocdef; varargspara:tlinkedlist):longint;virtual;abstract;

          { Return the location of the low and high part of a 64bit parameter }
          procedure splitparaloc64(const locpara:tparalocation;var loclopara,lochipara:tparalocation);virtual;

          procedure alloctempregs(list: taasmoutput;var locpara:tparalocation);virtual;
       end;


    var
       paramanager : tparamanager;


implementation

    uses
       cpuinfo,globals,systems,
       symbase,symsym,
       rgobj,cgobj,
       defutil,verbose;

    { true if uses a parameter as return value }
    function tparamanager.ret_in_param(def : tdef;calloption : tproccalloption) : boolean;
      begin
         ret_in_param:=(def.deftype in [arraydef,recorddef]) or
           ((def.deftype=stringdef) and (tstringdef(def).string_typ in [st_shortstring,st_longstring])) or
           ((def.deftype=procvardef) and (po_methodpointer in tprocvardef(def).procoptions)) or
           ((def.deftype=objectdef) and is_object(def)) or
           (def.deftype=variantdef) or
           ((def.deftype=setdef) and (tsetdef(def).settype<>smallset));
      end;


    function tparamanager.push_high_param(varspez:tvarspez;def : tdef;calloption : tproccalloption) : boolean;
      begin
         push_high_param:=not(calloption in [pocall_cdecl,pocall_cppdecl]) and
                          (
                           is_open_array(def) or
                           is_open_string(def) or
                           is_array_of_const(def)
                          );
      end;


    { true if a parameter is too large to copy and only the address is pushed }
    function tparamanager.push_addr_param(varspez:tvarspez;def : tdef;calloption : tproccalloption) : boolean;
      begin
        result:=false;
        { var,out always require address }
        if varspez in [vs_var,vs_out] then
          begin
            result:=true;
            exit;
          end;
        { Only vs_const, vs_value here }
        case def.deftype of
          variantdef,
          formaldef :
            result:=true;
          recorddef :
            result:=not(calloption in [pocall_cdecl,pocall_cppdecl]) and (def.size>pointer_size);
          arraydef :
            begin
              if (calloption in [pocall_cdecl,pocall_cppdecl]) then
               begin
                 { array of const values are pushed on the stack }
                 result:=not is_array_of_const(def);
               end
              else
               begin
                 result:=(
                          (tarraydef(def).highrange>=tarraydef(def).lowrange) and
                          (def.size>pointer_size)
                         ) or
                         is_open_array(def) or
                         is_array_of_const(def) or
                         is_array_constructor(def);
               end;
            end;
          objectdef :
            result:=is_object(def);
          stringdef :
            result:=not(calloption in [pocall_cdecl,pocall_cppdecl]) and (tstringdef(def).string_typ in [st_shortstring,st_longstring]);
          procvardef :
            result:=not(calloption in [pocall_cdecl,pocall_cppdecl]) and (po_methodpointer in tprocvardef(def).procoptions);
          setdef :
            result:=not(calloption in [pocall_cdecl,pocall_cppdecl]) and (tsetdef(def).settype<>smallset);
        end;
      end;


    { true if a parameter is too large to push and needs a concatcopy to get the value on the stack }
    function tparamanager.copy_value_on_stack(varspez:tvarspez;def : tdef;calloption : tproccalloption) : boolean;
      begin
        copy_value_on_stack:=false;
        { this is only for cdecl procedures with vs_const,vs_value }
        if not(
               (calloption in [pocall_cdecl,pocall_cppdecl]) and
               (varspez in [vs_value,vs_const])
              ) then
          exit;
        case def.deftype of
          variantdef,
          formaldef :
            copy_value_on_stack:=true;
          recorddef :
            copy_value_on_stack:=(def.size>pointer_size);
          arraydef :
            copy_value_on_stack:=(tarraydef(def).highrange>=tarraydef(def).lowrange) and
                                 (def.size>pointer_size);
          objectdef :
            copy_value_on_stack:=is_object(def);
          stringdef :
            copy_value_on_stack:=tstringdef(def).string_typ in [st_shortstring,st_longstring];
          procvardef :
            copy_value_on_stack:=(po_methodpointer in tprocvardef(def).procoptions);
          setdef :
            copy_value_on_stack:=(tsetdef(def).settype<>smallset);
        end;
      end;


    { return the size of a push }
    function tparamanager.push_size(varspez:tvarspez;def : tdef;calloption : tproccalloption) : longint;
      begin
        push_size:=-1;
        case varspez of
          vs_out,
          vs_var :
            push_size:=pointer_size;
          vs_value,
          vs_const :
            begin
                if push_addr_param(varspez,def,calloption) then
                  push_size:=pointer_size
                else
                  begin
                    { special array are normally pushed by addr, only for
                      cdecl array of const it comes here and the pushsize
                      is unknown }
                    if is_array_of_const(def) then
                      push_size:=0
                    else
                      push_size:=def.size;
                  end;
            end;
        end;
      end;


    function tparamanager.get_para_align(calloption : tproccalloption):byte;
      begin
        result:=std_param_align;
      end;


    function tparamanager.get_volatile_registers_int(calloption : tproccalloption):tsuperregisterset;
      begin
        result:=[];
      end;


    function tparamanager.get_volatile_registers_fpu(calloption : tproccalloption):tsuperregisterset;
      begin
        result:=[];
      end;


    procedure tparamanager.allocparaloc(list: taasmoutput; const loc: tparalocation);
      begin
        case loc.loc of
          LOC_REGISTER, LOC_CREGISTER:
            begin
              { NR_NO means we don't need to allocate the parameter.
                This is used for inlining parameters which allocates
                the parameters in gen_alloc_parast (PFV) }
              if loc.register<>NR_NO then
                begin
{$ifndef cpu64bit}
                  if (loc.size in [OS_64,OS_S64,OS_F64]) then
                    begin
                      cg.getexplicitregister(list,loc.registerhigh);
                      cg.getexplicitregister(list,loc.registerlow);
                    end
                  else
{$endif cpu64bit}
                    cg.getexplicitregister(list,loc.register);
                end;
            end;
          LOC_FPUREGISTER, LOC_CFPUREGISTER:
            begin
              if loc.register<>NR_NO then
                cg.getexplicitregister(list,loc.register);
            end;
          LOC_REFERENCE,LOC_CREFERENCE:
            { do nothing by default, most of the time it's the framepointer }
          else
            internalerror(200306091);
        end;
      end;


    procedure tparamanager.freeparaloc(list: taasmoutput; const loc: tparalocation);
      begin
        case loc.loc of
          LOC_REGISTER, LOC_CREGISTER:
            begin
{$ifndef cpu64bit}
              if (loc.size in [OS_64,OS_S64,OS_F64]) then
                begin
                  cg.ungetregister(list,loc.registerhigh);
                  cg.ungetregister(list,loc.registerlow);
                end
              else
{$endif cpu64bit}
                cg.ungetregister(list,loc.register);
            end;
          LOC_FPUREGISTER, LOC_CFPUREGISTER:
            cg.ungetregister(list,loc.register);
          LOC_REFERENCE,LOC_CREFERENCE:
            { do nothing by default, most of the time it's the framepointer }
          else
            internalerror(200306091);
        end;
      end;


    procedure tparamanager.splitparaloc64(const locpara:tparalocation;var loclopara,lochipara:tparalocation);
      begin
        if not(locpara.size in [OS_64,OS_S64]) then
          internalerror(200307023);
        lochipara:=locpara;
        loclopara:=locpara;
        if locpara.size=OS_S64 then
          lochipara.size:=OS_S32
        else
          lochipara.size:=OS_32;
        loclopara.size:=OS_32;
        case locpara.loc of
           LOC_REGISTER,LOC_CREGISTER:
             begin
               loclopara.register:=locpara.registerlow;
               lochipara.register:=locpara.registerhigh;
             end;
           LOC_REFERENCE:
             begin
               if target_info.endian=endian_big then
                 inc(loclopara.reference.offset,4)
               else
                 inc(lochipara.reference.offset,4);
             end;
           else
             internalerror(200307024);
        end;
      end;


    procedure tparamanager.alloctempregs(list: taasmoutput;var locpara:tparalocation);
      begin
        if locpara.loc<>LOC_REGISTER then
          internalerror(200308123);
{$ifndef cpu64bit}
        if locpara.size in [OS_64,OS_S64] then
          begin
            locpara.registerlow:=cg.getintregister(list,OS_32);
            locpara.registerhigh:=cg.getintregister(list,OS_32);
          end
        else
{$endif cpu64bit}
          locpara.register:=cg.getintregister(list,locpara.size);
      end;


    function tparamanager.create_inline_paraloc_info(p : tabstractprocdef):longint;
      var
        hp : tparaitem;
        paraloc : tparalocation;
        parasize : longint;
      begin
        parasize:=0;
        hp:=tparaitem(p.para.first);
        while assigned(hp) do
          begin
            if push_addr_param(hp.paratyp,hp.paratype.def,p.proccalloption) then
              paraloc.size:=OS_ADDR
            else
              paraloc.size:=def_cgsize(hp.paratype.def);
            if paraloc.size=OS_NO then
              internalerror(200309301);
            { Indicate parameter is loaded in register, the register
              will be allocated when the allocpara is called }
            paraloc.loc:=LOC_REGISTER;
            paraloc.register:=NR_NO;
(*
                paraloc.loc:=LOC_REFERENCE;
                paraloc.reference.index:=NR_FRAME_POINTER_REG;
                l:=push_size(hp.paratyp,hp.paratype.def,p.proccalloption);
                varalign:=size_2_align(l);
                paraloc.reference.offset:=parasize+target_info.first_parm_offset;
                varalign:=used_align(varalign,p.paraalign,p.paraalign);
                parasize:=align(parasize+l,varalign);
*)
            hp.paraloc[callerside]:=paraloc;
            hp.paraloc[calleeside]:=paraloc;
            hp:=tparaitem(hp.next);
          end;
        { We need to return the size allocated }
        result:=parasize;
      end;


initialization
  ;
finalization
  paramanager.free;
end.

{
   $Log$
   Revision 1.61  2003-10-09 21:31:37  daniel
     * Register allocator splitted, ans abstract now

   Revision 1.60  2003/10/05 21:21:52  peter
     * c style array of const generates callparanodes
     * varargs paraloc fixes

   Revision 1.59  2003/10/03 22:00:33  peter
     * parameter alignment fixes

   Revision 1.58  2003/10/01 20:34:49  peter
     * procinfo unit contains tprocinfo
     * cginfo renamed to cgbase
     * moved cgmessage to verbose
     * fixed ppc and sparc compiles

   Revision 1.57  2003/09/30 21:02:37  peter
     * updates for inlining

   Revision 1.56  2003/09/23 17:56:05  peter
     * locals and paras are allocated in the code generation
     * tvarsym.localloc contains the location of para/local when
       generating code for the current procedure

   Revision 1.55  2003/09/16 16:17:01  peter
     * varspez in calls to push_addr_param

   Revision 1.54  2003/09/10 08:31:47  marco
    * Patch from Peter for paraloc

   Revision 1.53  2003/09/07 22:09:35  peter
     * preparations for different default calling conventions
     * various RA fixes

   Revision 1.52  2003/09/04 15:39:58  peter
     * released useparatemp

   Revision 1.51  2003/09/03 15:55:01  peter
     * NEWRA branch merged

   Revision 1.50.2.1  2003/08/29 17:28:59  peter
     * next batch of updates

   Revision 1.50  2003/08/11 21:18:20  peter
     * start of sparc support for newra

   Revision 1.49  2003/07/08 21:24:59  peter
     * sparc fixes

   Revision 1.48  2003/07/05 20:11:41  jonas
     * create_paraloc_info() is now called separately for the caller and
       callee info
     * fixed ppc cycle

   Revision 1.47  2003/07/02 22:18:04  peter
     * paraloc splitted in callerparaloc,calleeparaloc
     * sparc calling convention updates

   Revision 1.46  2003/06/17 16:32:03  peter
     * allocpara/freepara 64bit support

   Revision 1.45  2003/06/13 21:19:30  peter
     * current_procdef removed, use current_procinfo.procdef instead

   Revision 1.44  2003/06/12 21:11:10  peter
     * ungetregisterfpu gets size parameter

   Revision 1.43  2003/06/09 14:54:26  jonas
     * (de)allocation of registers for parameters is now performed properly
       (and checked on the ppc)
     - removed obsolete allocation of all parameter registers at the start
       of a procedure (and deallocation at the end)

   Revision 1.42  2003/06/08 10:54:41  jonas
     - disabled changing of LOC_*REGISTER to LOC_C*REGISTER in setparalocs,
       this is not necessary anymore (doesn't do anything anymore actually,
       except making sure the interface crc changes)

   Revision 1.41  2003/06/07 18:57:04  jonas
     + added freeintparaloc
     * ppc get/freeintparaloc now check whether the parameter regs are
       properly allocated/deallocated (and get an extra list para)
     * ppc a_call_* now internalerrors if pi_do_call is not yet set
     * fixed lot of missing pi_do_call's

   Revision 1.40  2003/05/31 15:05:28  peter
     * FUNCTION_RESULT64_LOW/HIGH_REG added for int64 results

   Revision 1.39  2003/05/30 23:57:08  peter
     * more sparc cleanup
     * accumulator removed, splitted in function_return_reg (called) and
       function_result_reg (caller)

   Revision 1.38  2003/05/13 15:16:13  peter
     * removed ret_in_acc, it's the reverse of ret_in_param
     * fixed ret_in_param for win32 cdecl array

   Revision 1.37  2003/04/30 22:15:59  florian
     * some 64 bit adaptions in ncgadd
     * x86-64 now uses ncgadd
     * tparamanager.ret_in_acc doesn't return true anymore for a void-def

   Revision 1.36  2003/04/27 11:21:33  peter
     * aktprocdef renamed to current_procinfo.procdef
     * procinfo renamed to current_procinfo
     * procinfo will now be stored in current_module so it can be
       cleaned up properly
     * gen_main_procsym changed to create_main_proc and release_main_proc
       to also generate a tprocinfo structure
     * fixed unit implicit initfinal

   Revision 1.35  2003/04/27 07:29:50  peter
     * current_procinfo.procdef cleanup, current_procdef is now always nil when parsing
       a new procdef declaration
     * aktprocsym removed
     * lexlevel removed, use symtable.symtablelevel instead
     * implicit init/final code uses the normal genentry/genexit
     * funcret state checking updated for new funcret handling

   Revision 1.34  2003/04/23 13:15:04  peter
     * fix push_high_param for cdecl

   Revision 1.33  2003/04/23 10:14:30  peter
     * cdecl array of const has no addr push

   Revision 1.32  2003/04/22 13:47:08  peter
     * fixed C style array of const
     * fixed C array passing
     * fixed left to right with high parameters

   Revision 1.31  2003/02/02 19:25:54  carl
     * Several bugfixes for m68k target (register alloc., opcode emission)
     + VIS target
     + Generic add more complete (still not verified)

   Revision 1.30  2003/01/08 18:43:56  daniel
    * Tregister changed into a record

   Revision 1.29  2002/12/23 20:58:03  peter
     * remove unused global var

   Revision 1.28  2002/12/17 22:19:33  peter
     * fixed pushing of records>8 bytes with stdcall
     * simplified hightree loading

   Revision 1.27  2002/12/06 16:56:58  peter
     * only compile cs_fp_emulation support when cpufpuemu is defined
     * define cpufpuemu for m68k only

   Revision 1.26  2002/11/27 20:04:09  peter
     * tvarsym.get_push_size replaced by paramanager.push_size

   Revision 1.25  2002/11/27 02:33:19  peter
     * copy_value_on_stack method added for cdecl record passing

   Revision 1.24  2002/11/25 17:43:21  peter
     * splitted defbase in defutil,symutil,defcmp
     * merged isconvertable and is_equal into compare_defs(_ext)
     * made operator search faster by walking the list only once

   Revision 1.23  2002/11/18 17:31:58  peter
     * pass proccalloption to ret_in_xxx and push_xxx functions

   Revision 1.22  2002/11/16 18:00:04  peter
     * only push small arrays on the stack for win32

   Revision 1.21  2002/10/05 12:43:25  carl
     * fixes for Delphi 6 compilation
      (warning : Some features do not work under Delphi)

   Revision 1.20  2002/09/30 07:07:25  florian
     * fixes to common code to get the alpha compiler compiled applied

   Revision 1.19  2002/09/30 07:00:47  florian
     * fixes to common code to get the alpha compiler compiled applied

   Revision 1.18  2002/09/09 09:10:51  florian
     + added generic tparamanager.getframepointerloc

   Revision 1.17  2002/09/07 19:40:39  florian
     * tvarsym.paraitem is set now

   Revision 1.16  2002/09/01 21:04:48  florian
     * several powerpc related stuff fixed

   Revision 1.15  2002/08/25 19:25:19  peter
     * sym.insert_in_data removed
     * symtable.insertvardata/insertconstdata added
     * removed insert_in_data call from symtable.insert, it needs to be
       called separatly. This allows to deref the address calculation
     * procedures now calculate the parast addresses after the procedure
       directives are parsed. This fixes the cdecl parast problem
     * push_addr_param has an extra argument that specifies if cdecl is used
       or not

   Revision 1.14  2002/08/17 22:09:47  florian
     * result type handling in tcgcal.pass_2 overhauled
     * better tnode.dowrite
     * some ppc stuff fixed

   Revision 1.13  2002/08/17 09:23:38  florian
     * first part of procinfo rewrite

   Revision 1.12  2002/08/16 14:24:58  carl
     * issameref() to test if two references are the same (then emit no opcodes)
     + ret_in_reg to replace ret_in_acc
       (fix some register allocation bugs at the same time)
     + save_std_register now has an extra parameter which is the
       usedinproc registers

   Revision 1.11  2002/08/12 15:08:40  carl
     + stab register indexes for powerpc (moved from gdb to cpubase)
     + tprocessor enumeration moved to cpuinfo
     + linker in target_info is now a class
     * many many updates for m68k (will soon start to compile)
     - removed some ifdef or correct them for correct cpu

   Revision 1.10  2002/08/10 17:15:20  jonas
     * register parameters are now LOC_CREGISTER instead of LOC_REGISTER

   Revision 1.9  2002/08/09 07:33:02  florian
     * a couple of interface related fixes

   Revision 1.8  2002/08/06 20:55:21  florian
     * first part of ppc calling conventions fix

   Revision 1.7  2002/08/05 18:27:48  carl
     + more more more documentation
     + first version include/exclude (can't test though, not enough scratch for i386 :()...

   Revision 1.6  2002/07/30 20:50:43  florian
     * the code generator knows now if parameters are in registers

   Revision 1.5  2002/07/26 21:15:39  florian
     * rewrote the system handling

   Revision 1.4  2002/07/20 11:57:55  florian
     * types.pas renamed to defbase.pas because D6 contains a types
       unit so this would conflicts if D6 programms are compiled
     + Willamette/SSE2 instructions to assembler added

   Revision 1.3  2002/07/13 19:38:43  florian
     * some more generic calling stuff fixed

   Revision 1.2  2002/07/13 07:17:15  jonas
     * fixed memory leak reported by  Sergey Korshunoff

   Revision 1.1  2002/07/11 14:41:28  florian
     * start of the new generic parameter handling
}