Line data    Source code

       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       10223 : dwarf_frame_register (Dwarf_Frame *fs, int regno, Dwarf_Op *ops_mem,
      38             :                       Dwarf_Op **ops, size_t *nops)
      39             : {
      40             :   /* Maybe there was a previous error.  */
      41       10223 :   if (fs == NULL)
      42             :     return -1;
      43             : 
      44       10223 :   if (unlikely (regno < 0))
      45             :     {
      46           0 :       __libdw_seterrno (DWARF_E_INVALID_ACCESS);
      47           0 :       return -1;
      48             :     }
      49             : 
      50       10223 :   *ops = ops_mem;
      51       10223 :   *nops = 0;
      52             : 
      53       10223 :   if (unlikely ((size_t) regno >= fs->nregs))
      54             :     goto default_rule;
      55             : 
      56        5887 :   const struct dwarf_frame_register *reg = &fs->regs[regno];
      57             : 
      58        5887 :   switch (reg->rule)
      59             :     {
      60             :     case reg_unspecified:
      61       11527 :     default_rule:
      62             :       /* Use the default rule for registers not yet mentioned in CFI.  */
      63        7191 :       if (fs->cache->default_same_value)
      64             :         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           0 :     same_value:
      72             :       /* The location is not known here, but the caller might know it.  */
      73        2096 :       *ops = NULL;
      74        2096 :       break;
      75             : 
      76         835 :     case reg_offset:
      77             :     case reg_val_offset:
      78         835 :       ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_call_frame_cfa };
      79         835 :       if (reg->value != 0)
      80        1302 :         ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_plus_uconst,
      81         651 :                                           .number = reg->value };
      82         835 :       if (reg->rule == reg_val_offset)
      83             :         /* A value, not a location.  */
      84         175 :         ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_stack_value };
      85         835 :       *ops = ops_mem;
      86         835 :       break;
      87             : 
      88          73 :     case reg_register:
      89         146 :       ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_regx,
      90          73 :                                         .number = reg->value };
      91          73 :       break;
      92             : 
      93           9 :     case reg_val_expression:
      94             :     case reg_expression:
      95             :       {
      96          18 :         unsigned int address_size = (fs->cache->e_ident[EI_CLASS] == ELFCLASS32
      97           9 :                                      ? 4 : 8);
      98             : 
      99             :         Dwarf_Block block;
     100           9 :         const uint8_t *p = fs->cache->data->d.d_buf + reg->value;
     101           9 :         const uint8_t *end = (fs->cache->data->d.d_buf
     102           9 :                               + fs->cache->data->d.d_size);
     103           9 :         get_uleb128 (block.length, p, end);
     104           9 :         block.data = (void *) p;
     105             : 
     106             :         /* Parse the expression into internal form.  */
     107          27 :         if (__libdw_intern_expression (NULL,
     108           9 :                                        fs->cache->other_byte_order,
     109             :                                        address_size, 4,
     110           9 :                                        &fs->cache->expr_tree, &block,
     111           9 :                                        true, reg->rule == reg_val_expression,
     112             :                                        ops, nops, IDX_debug_frame) < 0)
     113           0 :           return -1;
     114           9 :         break;
     115             :       }
     116             :     }
     117             : 
     118             :   return 0;
     119             : }