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       1                 :            : /* Get register location expression for frame.
       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 "cfi.h"
      34                 :            : #include <dwarf.h>
      35                 :            : 
      36                 :            : int
      37                 :      20160 : dwarf_frame_register (Dwarf_Frame *fs, int regno, Dwarf_Op ops_mem[3],
      38                 :            :                       Dwarf_Op **ops, size_t *nops)
      39                 :            : {
      40                 :            :   /* Maybe there was a previous error.  */
      41         [ +  - ]:      20160 :   if (fs == NULL)
      42                 :            :     return -1;
      43                 :            : 
      44         [ -  + ]:      20160 :   if (unlikely (regno < 0))
      45                 :            :     {
      46                 :          0 :       __libdw_seterrno (DWARF_E_INVALID_ACCESS);
      47                 :          0 :       return -1;
      48                 :            :     }
      49                 :            : 
      50                 :      20160 :   *ops = ops_mem;
      51                 :      20160 :   *nops = 0;
      52                 :            : 
      53         [ +  + ]:      20160 :   if (unlikely ((size_t) regno >= fs->nregs))
      54                 :       8704 :     goto default_rule;
      55                 :            : 
      56                 :      11456 :   const struct dwarf_frame_register *reg = &fs->regs[regno];
      57                 :            : 
      58   [ +  +  +  +  :      11456 :   switch (reg->rule)
                   +  + ]
      59                 :            :     {
      60                 :            :     case reg_unspecified:
      61                 :      14296 :     default_rule:
      62                 :            :       /* Use the default rule for registers not yet mentioned in CFI.  */
      63         [ -  + ]:      14296 :       if (fs->cache->default_same_value)
      64                 :          0 :         goto same_value;
      65                 :            :       FALLTHROUGH;
      66                 :            :     case reg_undefined:
      67                 :            :       /* The value is known to be unavailable.  */
      68                 :            :       break;
      69                 :            : 
      70                 :            :     case reg_same_value:
      71                 :       4124 :     same_value:
      72                 :            :       /* The location is not known here, but the caller might know it.  */
      73                 :       4124 :       *ops = NULL;
      74                 :       4124 :       break;
      75                 :            : 
      76                 :       1556 :     case reg_offset:
      77                 :            :     case reg_val_offset:
      78                 :       1556 :       ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_call_frame_cfa };
      79         [ +  + ]:       1556 :       if (reg->value != 0)
      80                 :       1220 :         ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_plus_uconst,
      81                 :       1220 :                                           .number = reg->value };
      82         [ +  + ]:       1556 :       if (reg->rule == reg_val_offset)
      83                 :            :         /* A value, not a location.  */
      84                 :        318 :         ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_stack_value };
      85                 :       1556 :       *ops = ops_mem;
      86                 :       1556 :       break;
      87                 :            : 
      88                 :        146 :     case reg_register:
      89                 :        146 :       ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_regx,
      90                 :        146 :                                         .number = reg->value };
      91                 :        146 :       break;
      92                 :            : 
      93                 :         10 :     case reg_val_expression:
      94                 :            :     case reg_expression:
      95                 :            :       {
      96                 :         20 :         unsigned int address_size = (fs->cache->e_ident[EI_CLASS] == ELFCLASS32
      97         [ +  + ]:         10 :                                      ? 4 : 8);
      98                 :            : 
      99                 :         10 :         Dwarf_Block block;
     100                 :         10 :         const uint8_t *p = fs->cache->data->d.d_buf + reg->value;
     101                 :         10 :         const uint8_t *end = (fs->cache->data->d.d_buf
     102                 :         10 :                               + fs->cache->data->d.d_size);
     103         [ -  + ]:         10 :         if (p >= end)
     104                 :            :           {
     105                 :          0 :             __libdw_seterrno (DWARF_E_INVALID_DWARF);
     106                 :          0 :             return -1;
     107                 :            :           }
     108                 :         10 :         get_uleb128 (block.length, p, end);
     109                 :         10 :         block.data = (void *) p;
     110                 :            : 
     111                 :            :         /* Parse the expression into internal form.  */
     112         [ -  + ]:         10 :         if (__libdw_intern_expression (NULL,
     113                 :         10 :                                        fs->cache->other_byte_order,
     114                 :            :                                        address_size, 4,
     115                 :            :                                        &fs->cache->expr_tree, &block,
     116                 :         10 :                                        true, reg->rule == reg_val_expression,
     117                 :            :                                        ops, nops, IDX_debug_frame) < 0)
     118                 :            :           return -1;
     119                 :         10 :         break;
     120                 :            :       }
     121                 :            :     }
     122                 :            : 
     123                 :            :   return 0;
     124                 :            : }