LCOV - code coverage report
Current view: top level - backends - riscv_retval.c (source / functions) Hit Total Coverage
Test: elfutils-0.178 Lines: 0 65 0.0 %
Date: 2019-11-26 23:55:16 Functions: 0 4 0.0 %
Legend: Lines: hit not hit

          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             :    This file is part of elfutils.
       5             : 
       6             :    This file is free software; you can redistribute it and/or modify
       7             :    it under the terms of either
       8             : 
       9             :      * the GNU Lesser General Public License as published by the Free
      10             :        Software Foundation; either version 3 of the License, or (at
      11             :        your option) any later version
      12             : 
      13             :    or
      14             : 
      15             :      * the GNU General Public License as published by the Free
      16             :        Software Foundation; either version 2 of the License, or (at
      17             :        your option) any later version
      18             : 
      19             :    or both in parallel, as here.
      20             : 
      21             :    elfutils is distributed in the hope that it will be useful, but
      22             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      23             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      24             :    General Public License for more details.
      25             : 
      26             :    You should have received copies of the GNU General Public License and
      27             :    the GNU Lesser General Public License along with this program.  If
      28             :    not, see <http://www.gnu.org/licenses/>.  */
      29             : 
      30             : #ifdef HAVE_CONFIG_H
      31             : # include <config.h>
      32             : #endif
      33             : 
      34             : #include <stdio.h>
      35             : #include <inttypes.h>
      36             : 
      37             : #include <assert.h>
      38             : #include <dwarf.h>
      39             : 
      40             : #define BACKEND riscv_
      41             : #include "libebl_CPU.h"
      42             : 
      43             : static int
      44           0 : dwarf_bytesize_aux (Dwarf_Die *die, Dwarf_Word *sizep)
      45             : {
      46           0 :   int bits;
      47           0 :   if (((bits = 8 * dwarf_bytesize (die)) < 0
      48           0 :        && (bits = dwarf_bitsize (die)) < 0)
      49           0 :       || bits % 8 != 0)
      50           0 :     return -1;
      51             : 
      52           0 :   *sizep = bits / 8;
      53           0 :   return 0;
      54             : }
      55             : 
      56             : static int
      57             : pass_in_gpr_lp64 (const Dwarf_Op **locp, Dwarf_Word size)
      58             : {
      59           0 :   static const Dwarf_Op loc[] =
      60             :     {
      61             :       { .atom = DW_OP_reg10 }, { .atom = DW_OP_piece, .number = 8 },
      62             :       { .atom = DW_OP_reg11 }, { .atom = DW_OP_piece, .number = 8 }
      63             :     };
      64             : 
      65           0 :   *locp = loc;
      66           0 :   return size <= 8 ? 1 : 4;
      67             : }
      68             : 
      69             : static int
      70             : pass_by_ref (const Dwarf_Op **locp)
      71             : {
      72           0 :   static const Dwarf_Op loc[] = { { .atom = DW_OP_breg10 } };
      73             : 
      74           0 :   *locp = loc;
      75           0 :   return 1;
      76             : }
      77             : 
      78             : static int
      79             : pass_in_fpr_lp64f (const Dwarf_Op **locp, Dwarf_Word size)
      80             : {
      81           0 :   static const Dwarf_Op loc[] =
      82             :     {
      83             :       { .atom = DW_OP_regx, .number = 42 },
      84             :       { .atom = DW_OP_piece, .number = 4 },
      85             :       { .atom = DW_OP_regx, .number = 43 },
      86             :       { .atom = DW_OP_piece, .number = 4 }
      87             :     };
      88             : 
      89           0 :   *locp = loc;
      90           0 :   return size <= 4 ? 1 : 4;
      91             : }
      92             : 
      93             : static int
      94             : pass_in_fpr_lp64d (const Dwarf_Op **locp, Dwarf_Word size)
      95             : {
      96           0 :   static const Dwarf_Op loc[] =
      97             :     {
      98             :       { .atom = DW_OP_regx, .number = 42 },
      99             :       { .atom = DW_OP_piece, .number = 8 },
     100             :       { .atom = DW_OP_regx, .number = 43 },
     101             :       { .atom = DW_OP_piece, .number = 8 }
     102             :     };
     103             : 
     104           0 :   *locp = loc;
     105           0 :   return size <= 8 ? 1 : 4;
     106             : }
     107             : 
     108             : static int
     109           0 : flatten_aggregate_arg (Dwarf_Die *typedie __attribute__ ((unused)),
     110             :                        Dwarf_Die *arg0 __attribute__ ((unused)),
     111             :                        Dwarf_Die *arg1 __attribute__ ((unused)))
     112             : {
     113             :   /* ??? */
     114           0 :   return 1;
     115             : }
     116             : 
     117             : static int
     118           0 : pass_by_flattened_arg (const Dwarf_Op **locp __attribute__ ((unused)),
     119             :                        Dwarf_Word size __attribute__ ((unused)),
     120             :                        Dwarf_Die *arg0 __attribute__ ((unused)),
     121             :                        Dwarf_Die *arg1 __attribute__ ((unused)))
     122             : {
     123             :   /* ??? */
     124           0 :   return -2;
     125             : }
     126             : 
     127             : int
     128           0 : riscv_return_value_location_lp64d (Dwarf_Die *functypedie,
     129             :                                    const Dwarf_Op **locp)
     130             : {
     131             :   /* Start with the function's type, and get the DW_AT_type attribute,
     132             :      which is the type of the return value.  */
     133           0 :   Dwarf_Die typedie;
     134           0 :   int tag = dwarf_peeled_die_type (functypedie, &typedie);
     135           0 :   if (tag <= 0)
     136             :     return tag;
     137             : 
     138           0 :   Dwarf_Word size = (Dwarf_Word)-1;
     139             : 
     140             :   /* If the argument type is a Composite Type that is larger than 16
     141             :      bytes, then the argument is copied to memory allocated by the
     142             :      caller and the argument is replaced by a pointer to the copy.  */
     143           0 :   if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type
     144           0 :       || tag == DW_TAG_class_type || tag == DW_TAG_array_type)
     145             :     {
     146           0 :       Dwarf_Die arg0, arg1;
     147             : 
     148           0 :       if (dwarf_aggregate_size (&typedie, &size) < 0)
     149             :         return -1;
     150             :       /* A struct containing just one floating-point real is passed as though
     151             :          it were a standalone floating-point real.  A struct containing two
     152             :          floating-point reals is passed in two floating-point registers, if
     153             :          neither is more than FLEN bits wide.  A struct containing just one
     154             :          complex floating-point number is passed as though it were a struct
     155             :          containing two floating-point reals.  A struct containing one
     156             :          floating-point real and one integer (or bitfield), in either order,
     157             :          is passed in a floating-point register and an integer register,
     158             :          provided the floating-point real is no more than FLEN bits wide and
     159             :          the integer is no more than XLEN bits wide.  */
     160           0 :       if (tag == DW_TAG_structure_type
     161             :           && flatten_aggregate_arg (&typedie, &arg0, &arg1))
     162             :         return pass_by_flattened_arg (locp, size, &arg0, &arg1);
     163             :       /* Aggregates larger than 2*XLEN bits are passed by reference.  */
     164           0 :       else if (size > 16)
     165           0 :         return pass_by_ref (locp);
     166             :       /* Aggregates whose total size is no more than XLEN bits are passed in
     167             :          a register.  Aggregates whose total size is no more than 2*XLEN bits
     168             :          are passed in a pair of registers.  */
     169             :       else
     170           0 :         return pass_in_gpr_lp64 (locp, size);
     171             :     }
     172             : 
     173           0 :   if (tag == DW_TAG_base_type
     174           0 :       || tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
     175             :     {
     176           0 :       if (dwarf_bytesize_aux (&typedie, &size) < 0)
     177             :         {
     178           0 :           if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
     179           0 :             size = 8;
     180             :           else
     181             :             return -1;
     182             :         }
     183             : 
     184           0 :       Dwarf_Attribute attr_mem;
     185           0 :       if (tag == DW_TAG_base_type)
     186             :         {
     187           0 :           Dwarf_Word encoding;
     188           0 :           if (dwarf_formudata (dwarf_attr_integrate (&typedie, DW_AT_encoding,
     189             :                                                      &attr_mem),
     190             :                                &encoding) != 0)
     191             :             return -1;
     192             : 
     193           0 :           switch (encoding)
     194             :             {
     195           0 :             case DW_ATE_boolean:
     196             :             case DW_ATE_signed:
     197             :             case DW_ATE_unsigned:
     198             :             case DW_ATE_unsigned_char:
     199             :             case DW_ATE_signed_char:
     200             :               /* Scalars that are at most XLEN bits wide are passed in a single
     201             :                  argument register.  Scalars that are 2*XLEN bits wide are
     202             :                  passed in a pair of argument registers.  Scalars wider than
     203             :                  2*XLEN are passed by reference; there are none for LP64D.  */
     204           0 :               return pass_in_gpr_lp64 (locp, size);
     205             : 
     206           0 :             case DW_ATE_float:
     207             :               /* A real floating-point argument is passed in a floating-point
     208             :                  argument register if it is no more than FLEN bits wide,
     209             :                  otherwise it is passed according to the integer calling
     210             :                  convention.  */
     211           0 :               switch (size)
     212             :                 {
     213           0 :                 case 4: /* single */
     214             :                 case 8: /* double */
     215           0 :                   return pass_in_fpr_lp64d (locp, size);
     216             : 
     217           0 :                 case 16: /* quad */
     218           0 :                   return pass_in_gpr_lp64 (locp, size);
     219             : 
     220             :                 default:
     221             :                   return -2;
     222             :                 }
     223             : 
     224           0 :             case DW_ATE_complex_float:
     225             :               /* A complex floating-point number is passed as though it were a
     226             :                  struct containing two floating-point reals.  */
     227           0 :               switch (size)
     228             :                 {
     229           0 :                 case 8: /* float _Complex */
     230           0 :                   return pass_in_fpr_lp64f (locp, size);
     231             : 
     232           0 :                 case 16: /* double _Complex */
     233           0 :                   return pass_in_fpr_lp64d (locp, size);
     234             : 
     235             :                 case 32: /* long double _Complex */
     236           0 :                   return pass_by_ref (locp);
     237             : 
     238             :                 default:
     239             :                   return -2;
     240             :                 }
     241             :             }
     242             : 
     243             :           return -2;
     244             :         }
     245             :       else
     246           0 :         return pass_in_gpr_lp64 (locp, size);
     247             :     }
     248             : 
     249           0 :   *locp = NULL;
     250           0 :   return 0;
     251             : }

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