LCOV - code coverage report
Current view: top level - backends - riscv_retval.c (source / functions) Hit Total Coverage
Test: elfutils-0.191 Lines: 75 135 55.6 %
Date: 2024-07-23 19:52:03 Functions: 5 7 71.4 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 42 115 36.5 %

           Branch data     Line data    Source code
       1                 :            : /* Function return value location for Linux/RISC-V ABI.
       2                 :            :    Copyright (C) 2018 Sifive, Inc.
       3                 :            :    Copyright (C) 2013 Red Hat, Inc.
       4                 :            :    Copyright (C) 2024 Mark J. Wielaard <mark@klomp.org>
       5                 :            :    This file is part of elfutils.
       6                 :            : 
       7                 :            :    This file is free software; you can redistribute it and/or modify
       8                 :            :    it under the terms of either
       9                 :            : 
      10                 :            :      * the GNU Lesser General Public License as published by the Free
      11                 :            :        Software Foundation; either version 3 of the License, or (at
      12                 :            :        your option) any later version
      13                 :            : 
      14                 :            :    or
      15                 :            : 
      16                 :            :      * the GNU General Public License as published by the Free
      17                 :            :        Software Foundation; either version 2 of the License, or (at
      18                 :            :        your option) any later version
      19                 :            : 
      20                 :            :    or both in parallel, as here.
      21                 :            : 
      22                 :            :    elfutils is distributed in the hope that it will be useful, but
      23                 :            :    WITHOUT ANY WARRANTY; without even the implied warranty of
      24                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      25                 :            :    General Public License for more details.
      26                 :            : 
      27                 :            :    You should have received copies of the GNU General Public License and
      28                 :            :    the GNU Lesser General Public License along with this program.  If
      29                 :            :    not, see <http://www.gnu.org/licenses/>.  */
      30                 :            : 
      31                 :            : #ifdef HAVE_CONFIG_H
      32                 :            : # include <config.h>
      33                 :            : #endif
      34                 :            : 
      35                 :            : #include <stdio.h>
      36                 :            : #include <inttypes.h>
      37                 :            : 
      38                 :            : #include <assert.h>
      39                 :            : #include <dwarf.h>
      40                 :            : 
      41                 :            : #define BACKEND riscv_
      42                 :            : #include "libebl_CPU.h"
      43                 :            : 
      44                 :            : static int
      45                 :         18 : dwarf_bytesize_aux (Dwarf_Die *die, Dwarf_Word *sizep)
      46                 :            : {
      47                 :         18 :   int bits;
      48         [ -  + ]:         18 :   if (((bits = 8 * dwarf_bytesize (die)) < 0
      49         [ #  # ]:          0 :        && (bits = dwarf_bitsize (die)) < 0)
      50         [ -  + ]:         18 :       || bits % 8 != 0)
      51                 :          0 :     return -1;
      52                 :            : 
      53                 :         18 :   *sizep = bits / 8;
      54                 :         18 :   return 0;
      55                 :            : }
      56                 :            : 
      57                 :            : static int
      58                 :          6 : pass_in_gpr_lp64 (const Dwarf_Op **locp, Dwarf_Word size)
      59                 :            : {
      60                 :          6 :   static const Dwarf_Op loc[] =
      61                 :            :     {
      62                 :            :       { .atom = DW_OP_reg10 }, { .atom = DW_OP_piece, .number = 8 },
      63                 :            :       { .atom = DW_OP_reg11 }, { .atom = DW_OP_piece, .number = 8 }
      64                 :            :     };
      65                 :            : 
      66                 :          6 :   *locp = loc;
      67                 :          6 :   return size <= 8 ? 1 : 4;
      68                 :            : }
      69                 :            : 
      70                 :            : static int
      71                 :          0 : pass_by_ref (const Dwarf_Op **locp)
      72                 :            : {
      73                 :          0 :   static const Dwarf_Op loc[] = { { .atom = DW_OP_breg10 } };
      74                 :            : 
      75                 :          0 :   *locp = loc;
      76                 :          0 :   return 1;
      77                 :            : }
      78                 :            : 
      79                 :            : static int
      80                 :          0 : pass_in_fpr_lp64f (const Dwarf_Op **locp, Dwarf_Word size)
      81                 :            : {
      82                 :          0 :   static const Dwarf_Op loc[] =
      83                 :            :     {
      84                 :            :       { .atom = DW_OP_regx, .number = 42 },
      85                 :            :       { .atom = DW_OP_piece, .number = 4 },
      86                 :            :       { .atom = DW_OP_regx, .number = 43 },
      87                 :            :       { .atom = DW_OP_piece, .number = 4 }
      88                 :            :     };
      89                 :            : 
      90                 :          0 :   *locp = loc;
      91                 :          0 :   return size <= 4 ? 1 : 4;
      92                 :            : }
      93                 :            : 
      94                 :            : static int
      95                 :          4 : pass_in_fpr_lp64d (const Dwarf_Op **locp, Dwarf_Word size)
      96                 :            : {
      97                 :          4 :   static const Dwarf_Op loc[] =
      98                 :            :     {
      99                 :            :       { .atom = DW_OP_regx, .number = 42 },
     100                 :            :       { .atom = DW_OP_piece, .number = 8 },
     101                 :            :       { .atom = DW_OP_regx, .number = 43 },
     102                 :            :       { .atom = DW_OP_piece, .number = 8 }
     103                 :            :     };
     104                 :            : 
     105                 :          4 :   *locp = loc;
     106                 :          4 :   return size <= 8 ? 1 : 4;
     107                 :            : }
     108                 :            : 
     109                 :            : /* Checks if we can "flatten" the given type, Only handles the simple
     110                 :            :    cases where we have a struct with one or two the same base type
     111                 :            :    elements.  */
     112                 :            : static int
     113                 :          8 : flatten_aggregate_arg (Dwarf_Die *typedie,
     114                 :            :                        Dwarf_Word size,
     115                 :            :                        Dwarf_Die *arg0,
     116                 :            :                        Dwarf_Die *arg1)
     117                 :            : {
     118                 :          8 :   int tag0, tag1;
     119                 :          8 :   Dwarf_Die member;
     120                 :          8 :   Dwarf_Word encoding0, encoding1;
     121                 :          8 :   Dwarf_Attribute attr;
     122                 :          8 :   Dwarf_Word size0, size1;
     123                 :            : 
     124         [ -  + ]:          8 :   if (size < 8 || size > 16)
     125                 :            :     return 0;
     126                 :            : 
     127         [ -  + ]:          8 :   if (dwarf_child (typedie, arg0) != 0)
     128                 :            :     return 0;
     129                 :            : 
     130                 :          8 :   tag0 = dwarf_tag (arg0);
     131         [ -  + ]:          8 :   while (tag0 != -1 && tag0 != DW_TAG_member)
     132                 :            :     {
     133         [ #  # ]:          0 :       if (dwarf_siblingof (arg0, arg0) != 0)
     134                 :            :         return 0;
     135                 :          0 :       tag0 = dwarf_tag (arg0);
     136                 :            :     }
     137                 :            : 
     138         [ -  + ]:          8 :   if (tag0 != DW_TAG_member)
     139                 :            :     return 0;
     140                 :            : 
     141                 :            :   /* Remember where we are.  */
     142                 :          8 :   member = *arg0;
     143                 :            : 
     144                 :          8 :   tag0 = dwarf_peeled_die_type (arg0, arg0);
     145         [ -  + ]:          8 :   if (tag0 != DW_TAG_base_type)
     146                 :            :     return 0;
     147                 :            : 
     148         [ +  - ]:          8 :   if (dwarf_attr_integrate (arg0, DW_AT_encoding, &attr) == NULL
     149         [ -  + ]:          8 :       || dwarf_formudata (&attr, &encoding0) != 0)
     150                 :          0 :     return 0;
     151                 :            : 
     152         [ -  + ]:          8 :   if (dwarf_bytesize_aux (arg0, &size0) != 0)
     153                 :            :     return 0;
     154                 :            : 
     155         [ +  - ]:          8 :   if (size == size0)
     156                 :            :     return 1; /* This one member is the whole size. */
     157                 :            : 
     158         [ -  + ]:          8 :   if (size != 2 * size0)
     159                 :            :     return 0; /* We only handle two of the same.  */
     160                 :            : 
     161                 :            :   /* Look for another member with the same encoding.  */
     162         [ -  + ]:          8 :   if (dwarf_siblingof (&member, arg1) != 0)
     163                 :            :     return 0;
     164                 :            : 
     165                 :          8 :   tag1 = dwarf_tag (arg1);
     166         [ -  + ]:          8 :   while (tag1 != -1 && tag1 != DW_TAG_member)
     167                 :            :     {
     168         [ #  # ]:          0 :       if (dwarf_siblingof (arg1, arg1) != 0)
     169                 :            :         return 0;
     170                 :          0 :       tag1 = dwarf_tag (arg1);
     171                 :            :     }
     172                 :            : 
     173         [ -  + ]:          8 :   if (tag1 != DW_TAG_member)
     174                 :            :     return 0;
     175                 :            : 
     176                 :          8 :   tag1 = dwarf_peeled_die_type (arg1, arg1);
     177         [ -  + ]:          8 :   if (tag1 != DW_TAG_base_type)
     178                 :            :     return 0; /* We can only handle two equal base types for now. */
     179                 :            : 
     180         [ +  - ]:          8 :   if (dwarf_attr_integrate (arg1, DW_AT_encoding, &attr) == NULL
     181         [ +  - ]:          8 :       || dwarf_formudata (&attr, &encoding1) != 0
     182         [ -  + ]:          8 :       || encoding0 != encoding1)
     183                 :          0 :     return 0; /* We can only handle two of the same for now. */
     184                 :            : 
     185         [ -  + ]:          8 :   if (dwarf_bytesize_aux (arg1, &size1) != 0)
     186                 :            :     return 0;
     187                 :            : 
     188         [ -  + ]:          8 :   if (size0 != size1)
     189                 :            :     return 0; /* We can only handle two of the same for now. */
     190                 :            : 
     191                 :            :   return 1;
     192                 :            : }
     193                 :            : 
     194                 :            : /* arg0 and arg1 should be the peeled die types found by
     195                 :            :    flatten_aggregate_arg.  */
     196                 :            : static int
     197                 :          8 : pass_by_flattened_arg (const Dwarf_Op **locp,
     198                 :            :                        Dwarf_Word size,
     199                 :            :                        Dwarf_Die *arg0,
     200                 :            :                        Dwarf_Die *arg1 __attribute__((unused)))
     201                 :            : {
     202                 :            :   /* For now we just assume arg0 and arg1 are the same type and
     203                 :            :      encoding.  */
     204                 :          8 :   Dwarf_Word encoding;
     205                 :          8 :   Dwarf_Attribute attr;
     206                 :            : 
     207         [ +  - ]:          8 :   if (dwarf_attr_integrate (arg0, DW_AT_encoding, &attr) == NULL
     208         [ -  + ]:          8 :       || dwarf_formudata (&attr, &encoding) != 0)
     209                 :          0 :     return -1;
     210                 :            : 
     211      [ -  +  + ]:          8 :   switch (encoding)
     212                 :            :     {
     213                 :            :     case DW_ATE_boolean:
     214                 :            :     case DW_ATE_signed:
     215                 :            :     case DW_ATE_unsigned:
     216                 :            :     case DW_ATE_unsigned_char:
     217                 :            :     case DW_ATE_signed_char:
     218         [ +  + ]:          4 :       return pass_in_gpr_lp64 (locp, size);
     219                 :            : 
     220                 :            :     case DW_ATE_float:
     221         [ +  + ]:          4 :       return pass_in_fpr_lp64d (locp, size);
     222                 :            : 
     223                 :            :     default:
     224                 :            :       return -1;
     225                 :            :     }
     226                 :            : }
     227                 :            : 
     228                 :            : int
     229                 :         10 : riscv_return_value_location_lp64ifd (int fp, Dwarf_Die *functypedie,
     230                 :            :                                      const Dwarf_Op **locp)
     231                 :            : {
     232                 :            :   /* Start with the function's type, and get the DW_AT_type attribute,
     233                 :            :      which is the type of the return value.  */
     234                 :         10 :   Dwarf_Die typedie;
     235                 :         10 :   int tag = dwarf_peeled_die_type (functypedie, &typedie);
     236         [ +  - ]:         10 :   if (tag <= 0)
     237                 :            :     return tag;
     238                 :            : 
     239                 :         10 :   Dwarf_Word size = (Dwarf_Word)-1;
     240                 :            : 
     241                 :            :   /* If the argument type is a Composite Type that is larger than 16
     242                 :            :      bytes, then the argument is copied to memory allocated by the
     243                 :            :      caller and the argument is replaced by a pointer to the copy.  */
     244         [ +  + ]:         10 :   if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type
     245         [ -  + ]:          2 :       || tag == DW_TAG_class_type || tag == DW_TAG_array_type)
     246                 :            :     {
     247                 :          8 :       Dwarf_Die arg0, arg1;
     248                 :            : 
     249         [ +  - ]:          8 :       if (dwarf_aggregate_size (&typedie, &size) < 0)
     250                 :            :         return -1;
     251                 :            :       /* A struct containing just one floating-point real is passed as though
     252                 :            :          it were a standalone floating-point real.  A struct containing two
     253                 :            :          floating-point reals is passed in two floating-point registers, if
     254                 :            :          neither is more than FLEN bits wide.  A struct containing just one
     255                 :            :          complex floating-point number is passed as though it were a struct
     256                 :            :          containing two floating-point reals.  A struct containing one
     257                 :            :          floating-point real and one integer (or bitfield), in either order,
     258                 :            :          is passed in a floating-point register and an integer register,
     259                 :            :          provided the floating-point real is no more than FLEN bits wide and
     260                 :            :          the integer is no more than XLEN bits wide.  */
     261         [ +  - ]:          8 :       if (tag == DW_TAG_structure_type
     262         [ +  - ]:          8 :           && flatten_aggregate_arg (&typedie, size, &arg0, &arg1))
     263                 :          8 :         return pass_by_flattened_arg (locp, size, &arg0, &arg1);
     264                 :            :       /* Aggregates larger than 2*XLEN bits are passed by reference.  */
     265         [ #  # ]:          0 :       else if (size > 16)
     266                 :          0 :         return pass_by_ref (locp);
     267                 :            :       /* Aggregates whose total size is no more than XLEN bits are passed in
     268                 :            :          a register.  Aggregates whose total size is no more than 2*XLEN bits
     269                 :            :          are passed in a pair of registers.  */
     270                 :            :       else
     271         [ #  # ]:          0 :         return pass_in_gpr_lp64 (locp, size);
     272                 :            :     }
     273                 :            : 
     274   [ -  +  -  - ]:          2 :   if (tag == DW_TAG_base_type || dwarf_is_pointer (tag))
     275                 :            :     {
     276         [ -  + ]:          2 :       if (dwarf_bytesize_aux (&typedie, &size) < 0)
     277                 :            :         {
     278         [ #  # ]:          0 :           if (dwarf_is_pointer (tag))
     279                 :          0 :             size = 8;
     280                 :            :           else
     281                 :            :             return -1;
     282                 :            :         }
     283                 :            : 
     284                 :          2 :       Dwarf_Attribute attr_mem;
     285         [ +  - ]:          2 :       if (tag == DW_TAG_base_type)
     286                 :            :         {
     287                 :          2 :           Dwarf_Word encoding;
     288         [ +  - ]:          2 :           if (dwarf_formudata (dwarf_attr_integrate (&typedie, DW_AT_encoding,
     289                 :            :                                                      &attr_mem),
     290                 :            :                                &encoding) != 0)
     291                 :            :             return -1;
     292                 :            : 
     293   [ +  -  -  - ]:          2 :           switch (encoding)
     294                 :            :             {
     295                 :          2 :             case DW_ATE_boolean:
     296                 :            :             case DW_ATE_signed:
     297                 :            :             case DW_ATE_unsigned:
     298                 :            :             case DW_ATE_unsigned_char:
     299                 :            :             case DW_ATE_signed_char:
     300                 :            :               /* Scalars that are at most XLEN bits wide are passed in a single
     301                 :            :                  argument register.  Scalars that are 2*XLEN bits wide are
     302                 :            :                  passed in a pair of argument registers.  Scalars wider than
     303                 :            :                  2*XLEN are passed by reference; there are none for LP64D.  */
     304         [ -  + ]:          2 :               return pass_in_gpr_lp64 (locp, size);
     305                 :            : 
     306                 :          0 :             case DW_ATE_float:
     307                 :            :               /* A real floating-point argument is passed in a floating-point
     308                 :            :                  argument register if it is no more than FLEN bits wide,
     309                 :            :                  otherwise it is passed according to the integer calling
     310                 :            :                  convention.  */
     311   [ #  #  #  # ]:          0 :               switch (size)
     312                 :            :                 {
     313                 :          0 :                 case 4: /* single */
     314      [ #  #  # ]:          0 :                   switch (fp)
     315                 :            :                     {
     316                 :          0 :                     case EF_RISCV_FLOAT_ABI_DOUBLE:
     317                 :            :                     case EF_RISCV_FLOAT_ABI_SINGLE:
     318                 :          0 :                       return pass_in_fpr_lp64d (locp, size);
     319                 :          0 :                     case EF_RISCV_FLOAT_ABI_SOFT:
     320                 :          0 :                       return pass_in_gpr_lp64 (locp, size);
     321                 :            :                     default:
     322                 :            :                       return -2;
     323                 :            :                     }
     324                 :          0 :                 case 8: /* double */
     325      [ #  #  # ]:          0 :                   switch (fp)
     326                 :            :                     {
     327                 :          0 :                     case EF_RISCV_FLOAT_ABI_DOUBLE:
     328                 :          0 :                       return pass_in_fpr_lp64d (locp, size);
     329                 :          0 :                     case EF_RISCV_FLOAT_ABI_SINGLE:
     330                 :            :                     case EF_RISCV_FLOAT_ABI_SOFT:
     331                 :          0 :                       return pass_in_gpr_lp64 (locp, size);
     332                 :            :                     default:
     333                 :            :                       return -2;
     334                 :            :                     }
     335                 :            : 
     336                 :          0 :                 case 16: /* quad */
     337                 :          0 :                   return pass_in_gpr_lp64 (locp, size);
     338                 :            : 
     339                 :            :                 default:
     340                 :            :                   return -2;
     341                 :            :                 }
     342                 :            : 
     343                 :          0 :             case DW_ATE_complex_float:
     344                 :            :               /* A complex floating-point number is passed as though it were a
     345                 :            :                  struct containing two floating-point reals.  */
     346   [ #  #  #  # ]:          0 :               switch (size)
     347                 :            :                 {
     348                 :          0 :                 case 8: /* float _Complex */
     349      [ #  #  # ]:          0 :                   switch (fp)
     350                 :            :                     {
     351                 :          0 :                     case EF_RISCV_FLOAT_ABI_DOUBLE:
     352                 :            :                     case EF_RISCV_FLOAT_ABI_SINGLE:
     353                 :          0 :                       return pass_in_fpr_lp64f (locp, size);
     354                 :          0 :                     case EF_RISCV_FLOAT_ABI_SOFT:
     355                 :            :                       /* Double the size so the vals are two registers. */
     356                 :          0 :                       return pass_in_gpr_lp64 (locp, size * 2);
     357                 :            :                     default:
     358                 :            :                       return -2;
     359                 :            :                     }
     360                 :            : 
     361                 :          0 :                 case 16: /* double _Complex */
     362      [ #  #  # ]:          0 :                   switch (fp)
     363                 :            :                     {
     364                 :          0 :                     case EF_RISCV_FLOAT_ABI_DOUBLE:
     365                 :          0 :                       return pass_in_fpr_lp64d (locp, size);
     366                 :          0 :                     case EF_RISCV_FLOAT_ABI_SINGLE:
     367                 :            :                     case EF_RISCV_FLOAT_ABI_SOFT:
     368                 :          0 :                       return pass_in_gpr_lp64 (locp, size);
     369                 :            :                     default:
     370                 :            :                       return -2;
     371                 :            :                     }
     372                 :            : 
     373                 :            :                 case 32: /* long double _Complex */
     374                 :          0 :                   return pass_by_ref (locp);
     375                 :            : 
     376                 :            :                 default:
     377                 :            :                   return -2;
     378                 :            :                 }
     379                 :            :             }
     380                 :            : 
     381                 :            :           return -2;
     382                 :            :         }
     383                 :            :       else
     384         [ #  # ]:          0 :         return pass_in_gpr_lp64 (locp, size);
     385                 :            :     }
     386                 :            : 
     387                 :          0 :   *locp = NULL;
     388                 :          0 :   return 0;
     389                 :            : }
     390                 :            : 
     391                 :            : int
     392                 :         10 : riscv_return_value_location_lp64d (Dwarf_Die *functypedie,
     393                 :            :                                    const Dwarf_Op **locp)
     394                 :            : {
     395                 :         10 :   return riscv_return_value_location_lp64ifd (EF_RISCV_FLOAT_ABI_DOUBLE,
     396                 :            :                                               functypedie, locp);
     397                 :            : }
     398                 :            : 
     399                 :            : int
     400                 :          0 : riscv_return_value_location_lp64f (Dwarf_Die *functypedie,
     401                 :            :                                    const Dwarf_Op **locp)
     402                 :            : {
     403                 :          0 :   return riscv_return_value_location_lp64ifd (EF_RISCV_FLOAT_ABI_SINGLE,
     404                 :            :                                               functypedie, locp);
     405                 :            : }
     406                 :            : 
     407                 :            : int
     408                 :          0 : riscv_return_value_location_lp64 (Dwarf_Die *functypedie,
     409                 :            :                                   const Dwarf_Op **locp)
     410                 :            : {
     411                 :          0 :   return riscv_return_value_location_lp64ifd (EF_RISCV_FLOAT_ABI_SOFT,
     412                 :            :                                               functypedie, locp);
     413                 :            : }

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