Branch data     Line data    Source code

       1                 :            : /* Function return value location for ARM EABI.
       2                 :            :    Copyright (C) 2009-2010, 2014 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            : 
       5                 :            :    This file is free software; you can redistribute it and/or modify
       6                 :            :    it under the terms of either
       7                 :            : 
       8                 :            :      * the GNU Lesser General Public License as published by the Free
       9                 :            :        Software Foundation; either version 3 of the License, or (at
      10                 :            :        your option) any later version
      11                 :            : 
      12                 :            :    or
      13                 :            : 
      14                 :            :      * the GNU General Public License as published by the Free
      15                 :            :        Software Foundation; either version 2 of the License, or (at
      16                 :            :        your option) any later version
      17                 :            : 
      18                 :            :    or both in parallel, as here.
      19                 :            : 
      20                 :            :    elfutils is distributed in the hope that it will be useful, but
      21                 :            :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23                 :            :    General Public License for more details.
      24                 :            : 
      25                 :            :    You should have received copies of the GNU General Public License and
      26                 :            :    the GNU Lesser General Public License along with this program.  If
      27                 :            :    not, see <http://www.gnu.org/licenses/>.  */
      28                 :            : 
      29                 :            : #ifdef HAVE_CONFIG_H
      30                 :            : # include <config.h>
      31                 :            : #endif
      32                 :            : 
      33                 :            : #include <assert.h>
      34                 :            : #include <dwarf.h>
      35                 :            : 
      36                 :            : #define BACKEND arm_
      37                 :            : #include "libebl_CPU.h"
      38                 :            : 
      39                 :            : 
      40                 :            : /* r0, or pair r0, r1, or aggregate up to r0-r3.  */
      41                 :            : static const Dwarf_Op loc_intreg[] =
      42                 :            :   {
      43                 :            :     { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 },
      44                 :            :     { .atom = DW_OP_reg1 }, { .atom = DW_OP_piece, .number = 4 },
      45                 :            :     { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 },
      46                 :            :     { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 },
      47                 :            :   };
      48                 :            : #define nloc_intreg     1
      49                 :            : #define nloc_intregs(n) (2 * (n))
      50                 :            : 
      51                 :            : /* The return value is a structure and is actually stored in stack space
      52                 :            :    passed in a hidden argument by the caller.  But, the compiler
      53                 :            :    helpfully returns the address of that space in r0.  */
      54                 :            : static const Dwarf_Op loc_aggregate[] =
      55                 :            :   {
      56                 :            :     { .atom = DW_OP_breg0, .number = 0 }
      57                 :            :   };
      58                 :            : #define nloc_aggregate 1
      59                 :            : 
      60                 :            : 
      61                 :            : int
      62                 :          0 : arm_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
      63                 :            : {
      64                 :            :   /* Start with the function's type, and get the DW_AT_type attribute,
      65                 :            :      which is the type of the return value.  */
      66                 :          0 :   Dwarf_Die die_mem, *typedie = &die_mem;
      67                 :          0 :   int tag = dwarf_peeled_die_type (functypedie, typedie);
      68         [ #  # ]:          0 :   if (tag <= 0)
      69                 :            :     return tag;
      70                 :            : 
      71                 :          0 :   Dwarf_Word size;
      72   [ #  #  #  # ]:          0 :   switch (tag)
      73                 :            :     {
      74                 :            :     case -1:
      75                 :            :       return -1;
      76                 :            : 
      77                 :          0 :     case DW_TAG_subrange_type:
      78         [ #  # ]:          0 :       if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
      79                 :            :         {
      80                 :          0 :           Dwarf_Attribute attr_mem, *attr;
      81                 :          0 :           attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
      82                 :          0 :           typedie = dwarf_formref_die (attr, &die_mem);
      83         [ #  # ]:          0 :           tag = DWARF_TAG_OR_RETURN (typedie);
      84                 :            :         }
      85                 :          0 :       FALLTHROUGH;
      86                 :            : 
      87                 :            :     case DW_TAG_base_type:
      88                 :            :     case DW_TAG_enumeration_type:
      89                 :            :     CASE_POINTER:
      90                 :            :       {
      91                 :          0 :         Dwarf_Attribute attr_mem;
      92         [ #  # ]:          0 :         if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
      93                 :            :                                                    &attr_mem), &size) != 0)
      94                 :            :           {
      95         [ #  # ]:          0 :             if (dwarf_is_pointer (tag))
      96                 :          0 :               size = 4;
      97                 :            :             else
      98                 :            :               return -1;
      99                 :            :           }
     100         [ #  # ]:          0 :         if (size <= 16)
     101                 :            :           {
     102                 :          0 :           intreg:
     103                 :          0 :             *locp = loc_intreg;
     104         [ #  # ]:          0 :             return size <= 4 ? nloc_intreg : nloc_intregs ((size + 3) / 4);
     105                 :            :           }
     106                 :            : 
     107                 :          0 :       aggregate:
     108                 :          0 :         *locp = loc_aggregate;
     109                 :          0 :         return nloc_aggregate;
     110                 :            :       }
     111                 :            : 
     112                 :          0 :     case DW_TAG_structure_type:
     113                 :            :     case DW_TAG_class_type:
     114                 :            :     case DW_TAG_union_type:
     115                 :            :     case DW_TAG_array_type:
     116         [ #  # ]:          0 :       if (dwarf_aggregate_size (typedie, &size) == 0
     117   [ #  #  #  # ]:          0 :           && size > 0 && size <= 4)
     118                 :          0 :         goto intreg;
     119                 :          0 :       goto aggregate;
     120                 :            :     }
     121                 :            : 
     122                 :            :   /* XXX We don't have a good way to return specific errors from ebl calls.
     123                 :            :      This value means we do not understand the type, but it is well-formed
     124                 :            :      DWARF and might be valid.  */
     125                 :            :   return -2;
     126                 :            : }