Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 1 | /* Get register location expression for frame. |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame^] | 2 | Copyright (C) 2009-2010, 2014 Red Hat, Inc. |
| 3 | This file is part of elfutils. |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 4 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame^] | 5 | This file is free software; you can redistribute it and/or modify |
| 6 | it under the terms of either |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 7 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame^] | 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 |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 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 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame^] | 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/>. */ |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 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 | dwarf_frame_register (fs, regno, ops_mem, ops, nops) |
| 38 | Dwarf_Frame *fs; |
| 39 | int regno; |
| 40 | Dwarf_Op ops_mem[3]; |
| 41 | Dwarf_Op **ops; |
| 42 | size_t *nops; |
| 43 | { |
| 44 | /* Maybe there was a previous error. */ |
| 45 | if (fs == NULL) |
| 46 | return -1; |
| 47 | |
| 48 | if (unlikely (regno < 0)) |
| 49 | { |
| 50 | __libdw_seterrno (DWARF_E_INVALID_ACCESS); |
| 51 | return -1; |
| 52 | } |
| 53 | |
| 54 | *ops = ops_mem; |
| 55 | *nops = 0; |
| 56 | |
| 57 | if (unlikely ((size_t) regno >= fs->nregs)) |
| 58 | goto default_rule; |
| 59 | |
| 60 | const struct dwarf_frame_register *reg = &fs->regs[regno]; |
| 61 | |
| 62 | switch (reg->rule) |
| 63 | { |
| 64 | case reg_unspecified: |
| 65 | default_rule: |
| 66 | /* Use the default rule for registers not yet mentioned in CFI. */ |
| 67 | if (fs->cache->default_same_value) |
| 68 | goto same_value; |
| 69 | /*FALLTHROUGH*/ |
| 70 | case reg_undefined: |
| 71 | /* The value is known to be unavailable. */ |
| 72 | break; |
| 73 | |
| 74 | case reg_same_value: |
| 75 | same_value: |
| 76 | /* The location is not known here, but the caller might know it. */ |
| 77 | *ops = NULL; |
| 78 | break; |
| 79 | |
| 80 | case reg_offset: |
| 81 | case reg_val_offset: |
| 82 | ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_call_frame_cfa }; |
| 83 | if (reg->value != 0) |
| 84 | ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_plus_uconst, |
| 85 | .number = reg->value }; |
| 86 | if (reg->rule == reg_val_offset) |
| 87 | /* A value, not a location. */ |
| 88 | ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_stack_value }; |
| 89 | *ops = ops_mem; |
| 90 | break; |
| 91 | |
| 92 | case reg_register: |
| 93 | ops_mem[(*nops)++] = (Dwarf_Op) { .atom = DW_OP_regx, |
| 94 | .number = reg->value }; |
| 95 | break; |
| 96 | |
| 97 | case reg_val_expression: |
| 98 | case reg_expression: |
| 99 | { |
| 100 | unsigned int address_size = (fs->cache->e_ident[EI_CLASS] == ELFCLASS32 |
| 101 | ? 4 : 8); |
| 102 | |
| 103 | Dwarf_Block block; |
| 104 | const uint8_t *p = fs->cache->data->d.d_buf + reg->value; |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame^] | 105 | const uint8_t *end = (fs->cache->data->d.d_buf |
| 106 | + fs->cache->data->d.d_size); |
| 107 | get_uleb128 (block.length, p, end); |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 108 | block.data = (void *) p; |
| 109 | |
| 110 | /* Parse the expression into internal form. */ |
| 111 | if (__libdw_intern_expression (NULL, |
| 112 | fs->cache->other_byte_order, |
| 113 | address_size, 4, |
| 114 | &fs->cache->expr_tree, &block, |
| 115 | true, reg->rule == reg_val_expression, |
| 116 | ops, nops, IDX_debug_frame) < 0) |
| 117 | return -1; |
| 118 | break; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | return 0; |
| 123 | } |