freepascal.compiler/compiler/riscv64/cpupara.pas

{
    Copyright (c) 2002 by Florian Klaempfl

    RiscV64 specific calling conventions

    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.
 ****************************************************************************
}
unit cpupara;

{$I fpcdefs.inc}

  interface

    uses
      globtype,
      aasmtai,aasmdata,
      cpubase,
      symconst, symtype, symdef, symsym,
      paramgr, parabase, cgbase, cgutils;

    type
      tcpuparamanager = class(tparamanager)
        function get_volatile_registers_int(calloption: tproccalloption): tcpuregisterset; override;
        function get_volatile_registers_fpu(calloption: tproccalloption): tcpuregisterset; override;
        function push_addr_param(varspez: tvarspez; def: tdef; calloption: tproccalloption): boolean; override;
        function ret_in_param(def: tdef; pd: tabstractprocdef): boolean; override;

        procedure getintparaloc(list: TAsmList; pd : tabstractprocdef; nr: longint; var cgpara: tcgpara); override;
        function create_paraloc_info(p: tabstractprocdef; side: tcallercallee): longint; override;
        function create_varargs_paraloc_info(p: tabstractprocdef; side: tcallercallee; varargspara: tvarargsparalist): longint; override;
        function get_funcretloc(p : tabstractprocdef; side: tcallercallee; forcetempdef: tdef): tcgpara;override;

      private
        procedure init_values(var curintreg, curfloatreg, curmmreg: tsuperregister; var cur_stack_offset: aword);
        function create_paraloc_info_intern(p: tabstractprocdef; side: tcallercallee; paras: tparalist; var curintreg, curfloatreg, curmmreg: tsuperregister; var cur_stack_offset: aword; isVararg : boolean): longint;
        function parseparaloc(p: tparavarsym; const s: string): boolean; override;
        procedure create_paraloc_for_def(var para: TCGPara; varspez: tvarspez; paradef: tdef; var nextfloatreg, nextintreg: tsuperregister; var stack_offset: aword; const isVararg, forceintmem: boolean; const side: tcallercallee; const p: tabstractprocdef);
      end;

implementation

    uses
      verbose, systems,
      globals, cpuinfo,
      defutil,symtable,symcpu,
      procinfo, cpupi;

    function tcpuparamanager.get_volatile_registers_int(calloption: tproccalloption): tcpuregisterset;
      begin
        result:=[RS_X0..RS_X31]-[RS_X2,RS_X8..RS_X9,RS_X18..RS_X27];
      end;

    function tcpuparamanager.get_volatile_registers_fpu(calloption: tproccalloption): tcpuregisterset;
      begin
        result:=[RS_F0..RS_F31]-[RS_F8..RS_F9,RS_F18..RS_F27];
      end;

    procedure tcpuparamanager.getintparaloc(list: TAsmList; pd : tabstractprocdef; nr: longint; var cgpara: tcgpara);
      var
        paraloc: pcgparalocation;
        psym: tparavarsym;
        pdef: tdef;
      begin
        psym:=tparavarsym(pd.paras[nr-1]);
        pdef:=psym.vardef;
        if push_addr_param(psym.varspez,pdef,pd.proccalloption) then
          pdef:=cpointerdef.getreusable_no_free(pdef);
        cgpara.reset;
        cgpara.size := def_cgsize(pdef);
        cgpara.intsize := tcgsize2size[cgpara.size];
        cgpara.alignment := get_para_align(pd.proccalloption);
        cgpara.def:=pdef;
        paraloc := cgpara.add_location;
        with paraloc^ do begin
          size := def_cgsize(pdef);
          def := pdef;
          if (nr <= 8) then begin
            if (nr = 0) then
              internalerror(200309271);
            loc := LOC_REGISTER;
            register := newreg(R_INTREGISTER, RS_X10 + nr-1, R_SUBWHOLE);
          end else begin
            loc := LOC_REFERENCE;
            paraloc^.reference.index := NR_STACK_POINTER_REG;
            reference.offset := sizeof(aint) * (nr - 9);
          end;
        end;
      end;

    function getparaloc(p: tdef): tcgloc;
      begin
        { Later, the LOC_REFERENCE is in most cases changed into LOC_REGISTER
          if push_addr_param for the def is true
        }
        case p.typ of
          orddef:
            result := LOC_REGISTER;
          floatdef:
            if (cs_fp_emulation in current_settings.moduleswitches) or
               (current_settings.fputype in [fpu_soft]) then
              result := LOC_REGISTER
            else
              result := LOC_FPUREGISTER;
          enumdef:
            result := LOC_REGISTER;
          pointerdef:
            result := LOC_REGISTER;
          formaldef:
            result := LOC_REGISTER;
          classrefdef:
            result := LOC_REGISTER;
          procvardef,
          recorddef:
            result := LOC_REGISTER;
          objectdef:
            if is_object(p) then
              result := LOC_REFERENCE
            else
              result := LOC_REGISTER;
          stringdef:
            if is_shortstring(p) or is_longstring(p) then
              result := LOC_REFERENCE
            else
              result := LOC_REGISTER;
          filedef:
            result := LOC_REGISTER;
          arraydef:
            if is_dynamic_array(p) then
              getparaloc:=LOC_REGISTER
            else
              result := LOC_REFERENCE;
          setdef:
            if is_smallset(p) then
              result := LOC_REGISTER
            else
              result := LOC_REFERENCE;
          variantdef:
            result := LOC_REFERENCE;
          { avoid problems with errornous definitions }
          errordef:
            result := LOC_REGISTER;
        else
          internalerror(2002071001);
        end;
      end;

    function tcpuparamanager.push_addr_param(varspez: tvarspez; def: tdef; calloption: tproccalloption): boolean;
      begin
        result := false;
        { var,out,constref always require address }
        if varspez in [vs_var, vs_out, vs_constref] then
        begin
          result := true;
          exit;
        end;
        case def.typ of
          variantdef,
          formaldef:
            result := true;
          procvardef,
          recorddef:
            result := (def.size > 16);
          arraydef:
            result := (tarraydef(def).highrange >= tarraydef(def).lowrange) or
              is_open_array(def) or
              is_array_of_const(def) or
              is_array_constructor(def);
          objectdef:
            result := is_object(def);
          setdef:
            result := not is_smallset(def);
          stringdef:
            result := tstringdef(def).stringtype in [st_shortstring, st_longstring];
        end;
      end;

    function tcpuparamanager.ret_in_param(def: tdef; pd: tabstractprocdef): boolean;
      var
        tmpdef: tdef;
      begin
        if handle_common_ret_in_param(def,pd,result) then
          exit;

        { general rule: passed in registers -> returned in registers }
        result:=push_addr_param(vs_value,def,pd.proccalloption);
      end;

    procedure tcpuparamanager.init_values(var curintreg, curfloatreg, curmmreg: tsuperregister; var cur_stack_offset: aword);
      begin
        { register parameter save area begins at 48(r2) }
        cur_stack_offset := 0;
        curintreg := RS_X10;
        curfloatreg := RS_F10;
        curmmreg := RS_NO;
      end;

    function tcpuparamanager.get_funcretloc(p : tabstractprocdef; side: tcallercallee; forcetempdef: tdef): tcgpara;
      var
        paraloc: pcgparalocation;
        retcgsize: tcgsize;
        nextfloatreg, nextintreg, nextmmreg: tsuperregister;
        stack_offset: aword;
      begin
        if set_common_funcretloc_info(p,forcetempdef,retcgsize,result) then
          exit;

         { in this case, it must be returned in registers as if it were passed
           as the first parameter }
         init_values(nextintreg,nextfloatreg,nextmmreg,stack_offset);
         create_paraloc_for_def(result,vs_value,result.def,nextfloatreg,nextintreg,stack_offset,false,false,side,p);
         { sanity check (LOC_VOID for empty records) }
         if not assigned(result.location) or
            not(result.location^.loc in [LOC_REGISTER,LOC_FPUREGISTER,LOC_VOID]) then
           internalerror(2014113001);
      end;

    function tcpuparamanager.create_paraloc_info(p: tabstractprocdef; side: tcallercallee): longint;
      var
        cur_stack_offset: aword;
        curintreg, curfloatreg, curmmreg : tsuperregister;
      begin
        init_values(curintreg, curfloatreg, curmmreg, cur_stack_offset);

        result := create_paraloc_info_intern(p, side, p.paras, curintreg, curfloatreg, curmmreg, cur_stack_offset, false);

        create_funcretloc_info(p, side);
      end;

    function tcpuparamanager.create_paraloc_info_intern(p: tabstractprocdef; side: tcallercallee; paras: tparalist; var curintreg, curfloatreg, curmmreg: tsuperregister; var cur_stack_offset: aword; isVararg : boolean): longint;
      var
        nextintreg, nextfloatreg, nextmmreg : tsuperregister;
        i: integer;
        hp: tparavarsym;
        paraloc: pcgparalocation;
        delphi_nestedfp: boolean;

      begin
{$IFDEF extdebug}
        if po_explicitparaloc in p.procoptions then
          internalerror(200411141);
{$ENDIF extdebug}

        result := 0;
        nextintreg := curintreg;
        nextfloatreg := curfloatreg;
        nextmmreg := curmmreg;

        for i := 0 to paras.count - 1 do begin
          hp := tparavarsym(paras[i]);

          if (vo_has_explicit_paraloc in hp.varoptions) then begin
            internalerror(200412153);
          end;

          { currently only support C-style array of const }
          if (p.proccalloption in [pocall_cdecl, pocall_cppdecl]) and
            is_array_of_const(hp.vardef) then begin
            paraloc := hp.paraloc[side].add_location;
            { hack: the paraloc must be valid, but is not actually used }
            paraloc^.loc := LOC_REGISTER;
            paraloc^.register := NR_X0;
            paraloc^.size := OS_ADDR;
            paraloc^.def := voidpointertype;
            break;
          end;
          delphi_nestedfp:=(vo_is_parentfp in hp.varoptions) and (po_delphi_nested_cc in p.procoptions);
          create_paraloc_for_def(hp.paraloc[side], hp.varspez, hp.vardef,
            nextfloatreg, nextintreg, cur_stack_offset, isVararg, delphi_nestedfp, side, p);
        end;

        curintreg := nextintreg;
        curfloatreg := nextfloatreg;
        curmmreg := nextmmreg;
        result := cur_stack_offset;
      end;

    procedure tcpuparamanager.create_paraloc_for_def(var para: TCGPara; varspez: tvarspez; paradef: tdef; var nextfloatreg, nextintreg: tsuperregister; var stack_offset: aword; const isVararg, forceintmem: boolean; const side: tcallercallee; const p: tabstractprocdef);
      var
        paracgsize: tcgsize;
        loc: tcgloc;
        paraloc: pcgparalocation;
        { def to use for all paralocs if <> nil }
        alllocdef,
        { def to use for the current paraloc }
        locdef,
        tmpdef: tdef;
        paralen: aint;
        firstparaloc,
        paraaligned: boolean;
      begin
        alllocdef:=nil;
        locdef:=nil;
        para.reset;
        { have we ensured that the next parameter location will be aligned to the
          next 8 byte boundary? }
        paraaligned:=false;
        if push_addr_param(varspez, paradef, p.proccalloption) then begin
          paradef := cpointerdef.getreusable_no_free(paradef);
          loc := LOC_REGISTER;
          paracgsize := OS_ADDR;
          paralen := tcgsize2size[OS_ADDR];
        end else begin
          if not is_special_array(paradef) then
            paralen := paradef.size
          else
            paralen := tcgsize2size[def_cgsize(paradef)];

          if (paradef.typ=recorddef) and
             tabstractrecordsymtable(tabstractrecorddef(paradef).symtable).has_single_field(tmpdef) and
             (tmpdef.typ=floatdef) then
            begin
              paradef:=tmpdef;
              loc:=getparaloc(paradef);
              paracgsize:=def_cgsize(paradef)
            end
          else if (((paradef.typ=arraydef) and not
               is_special_array(paradef)) or
              (paradef.typ=recorddef)) then
            begin
              { general fallback rule: pass aggregate types in integer registers
                without special adjustments (incl. Darwin h) }
              loc:=LOC_REGISTER;
              paracgsize:=int_cgsize(paralen);
            end
          else
            begin
              loc:=getparaloc(paradef);
              paracgsize:=def_cgsize(paradef);
              { for things like formaldef }
              if (paracgsize=OS_NO) then
                begin
                  paracgsize:=OS_ADDR;
                  paralen:=tcgsize2size[OS_ADDR];
                end;
            end
        end;

        { patch FPU values into integer registers if we are processing varargs }
        if (isVararg) and (paradef.typ = floatdef) then begin
          loc := LOC_REGISTER;
          if paracgsize = OS_F64 then
            paracgsize := OS_64
          else
            paracgsize := OS_32;
        end;


        para.alignment := std_param_align;
        para.size := paracgsize;
        para.intsize := paralen;
        para.def := paradef;
        if (paralen = 0) then
          if (paradef.typ = recorddef) then begin
            paraloc := para.add_location;
            paraloc^.loc := LOC_VOID;
          end else
            internalerror(2005011310);
        if not assigned(alllocdef) then
          locdef:=paradef
        else
          begin
            locdef:=alllocdef;
            paracgsize:=def_cgsize(locdef);
          end;
        firstparaloc:=true;

        // Parameters passed in 2 registers are passed in a register starting with an even number.
        if isVararg and
           (paralen > 8) and
           (loc = LOC_REGISTER) and
           (nextintreg <= RS_X17) and
           odd(nextintreg) then
          inc(nextintreg);

        { can become < 0 for e.g. 3-byte records }
        while (paralen > 0) do begin
          paraloc := para.add_location;
          { In case of po_delphi_nested_cc, the parent frame pointer
            is always passed on the stack. }
          if (loc = LOC_REGISTER) and
             (nextintreg <= RS_X17) and
             not forceintmem then begin
            paraloc^.loc := loc;

            { make sure we don't lose whether or not the type is signed }
            if (paracgsize <> OS_NO) and
               (paradef.typ <> orddef) and
               not assigned(alllocdef) then
              begin
                paracgsize := int_cgsize(paralen);
                locdef:=get_paraloc_def(paradef, paralen, firstparaloc);
              end;

             if (paracgsize in [OS_NO, OS_128, OS_S128]) then
              begin
                if (paralen>4) then
                  begin
                    paraloc^.size := OS_INT;
                    paraloc^.def := osuinttype;
                  end
                else
                  begin
                    { for 3-byte records aligned in the lower bits of register }
                    paraloc^.size := OS_32;
                    paraloc^.def := u32inttype;
                  end;
              end
            else
              begin
                paraloc^.size := paracgsize;
                paraloc^.def := locdef;
              end;

            paraloc^.register := newreg(R_INTREGISTER, nextintreg, R_SUBNONE);
            inc(nextintreg);
            dec(paralen, tcgsize2size[paraloc^.size]);
          end else if (loc = LOC_FPUREGISTER) and
            (nextfloatreg <= RS_F17) then begin
            paraloc^.loc := loc;
            paraloc^.size := paracgsize;
            paraloc^.def := locdef;
            paraloc^.register := newreg(R_FPUREGISTER, nextfloatreg, R_SUBWHOLE);
            { the RiscV ABI says that the GPR index is increased for every parameter, no matter
              which type it is stored in

               not really, https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#hardware-floating-point-calling-convention says
               otherwise, gcc doesn't do it either }
            inc(nextfloatreg);
            dec(paralen, tcgsize2size[paraloc^.size]);
          end else if (loc = LOC_MMREGISTER) then begin
            { no mm registers }
            internalerror(2018072601);
          end else begin
            { either LOC_REFERENCE, or one of the above which must be passed on the
            stack because of insufficient registers }
            paraloc^.loc := LOC_REFERENCE;
            case loc of
              LOC_FPUREGISTER:
                begin
                  paraloc^.size:=int_float_cgsize(paralen);
                  case paraloc^.size of
                    OS_F32: paraloc^.def:=s32floattype;
                    OS_F64: paraloc^.def:=s64floattype;
                    else
                      internalerror(2013060122);
                  end;
                end;
              LOC_REGISTER,
              LOC_REFERENCE:
                begin
                  paraloc^.size:=int_cgsize(paralen);
                  paraloc^.def:=get_paraloc_def(paradef, paralen, firstparaloc);
                end;
              else
                internalerror(2006011101);
            end;
            if (side = callerside) then
              paraloc^.reference.index := NR_STACK_POINTER_REG
            else begin
              { during procedure entry, NR_OLD_STACK_POINTER_REG contains the old stack pointer }
              paraloc^.reference.index := NR_FRAME_POINTER_REG;
              { create_paraloc_info_intern might be also called when being outside of
                code generation so current_procinfo might be not set }
              if assigned(current_procinfo) then
                trv64procinfo(current_procinfo).needs_frame_pointer := true;
            end;
            paraloc^.reference.offset := stack_offset;

            { align temp contents to next register size }
            if not paraaligned then
              inc(stack_offset, align(paralen, 8))
            else
              inc(stack_offset, paralen);
            paralen := 0;
          end;
          firstparaloc:=false;
        end;
      end;

function tcpuparamanager.create_varargs_paraloc_info(p: tabstractprocdef; side: tcallercallee;
  varargspara: tvarargsparalist): longint;
var
  cur_stack_offset: aword;
  parasize, l: longint;
  curintreg, firstfloatreg, curfloatreg, curmmreg: tsuperregister;
  i: integer;
  hp: tparavarsym;
  paraloc: pcgparalocation;
begin
  init_values(curintreg, curfloatreg, curmmreg, cur_stack_offset);
  firstfloatreg := curfloatreg;

  result := create_paraloc_info_intern(p, side, p.paras, curintreg,
    curfloatreg, curmmreg, cur_stack_offset, false);
  if (p.proccalloption in [pocall_cdecl, pocall_cppdecl, pocall_mwpascal]) then
    begin
      { just continue loading the parameters in the registers }
      if assigned(varargspara) then
        begin
          if side=callerside then
            result := create_paraloc_info_intern(p, side, varargspara, curintreg,
              curfloatreg, curmmreg, cur_stack_offset, true)
          else
            internalerror(2019021918);
          if curfloatreg <> firstfloatreg then
            include(varargspara.varargsinfo, va_uses_float_reg);
        end;
      { varargs routines have to reserve at least 64 bytes for the RiscV ABI }
      if (result < 64) then
        result := 64;
    end
  else
    internalerror(2019021913);

  create_funcretloc_info(p, side);
end;

function tcpuparamanager.parseparaloc(p: tparavarsym; const s: string): boolean;
begin
  internalerror(200404182);
  result := true;
end;


begin
  paramanager := tcpuparamanager.create;
end.