1 /* Return DWARF attribute associated with a location expression op. 2 Copyright (C) 2013, 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 <dwarf.h> 34 #include <libdwP.h> 35 36 static Dwarf_CU * 37 attr_form_cu (Dwarf_Attribute *attr) 38 { 39 /* If the attribute has block/expr form the data comes from the 40 .debug_info from the same cu as the attr. Otherwise it comes from 41 the .debug_loc data section. */ 42 switch (attr->form) 43 { 44 case DW_FORM_block1: 45 case DW_FORM_block2: 46 case DW_FORM_block4: 47 case DW_FORM_block: 48 case DW_FORM_exprloc: 49 return attr->cu; 50 default: 51 return attr->cu->dbg->fake_loc_cu; 52 } 53 } 54 55 int 56 dwarf_getlocation_attr (Dwarf_Attribute *attr, const Dwarf_Op *op, Dwarf_Attribute *result) 57 { 58 if (attr == NULL) 59 return -1; 60 61 switch (op->atom) 62 { 63 case DW_OP_implicit_value: 64 result->code = DW_AT_const_value; 65 result->form = DW_FORM_block; 66 result->valp = (unsigned char *) (uintptr_t) op->number2; 67 result->cu = attr_form_cu (attr); 68 break; 69 70 case DW_OP_GNU_entry_value: 71 result->code = DW_AT_location; 72 result->form = DW_FORM_exprloc; 73 result->valp = (unsigned char *) (uintptr_t) op->number2; 74 result->cu = attr_form_cu (attr); 75 break; 76 77 case DW_OP_GNU_const_type: 78 result->code = DW_AT_const_value; 79 result->form = DW_FORM_block1; 80 result->valp = (unsigned char *) (uintptr_t) op->number2; 81 result->cu = attr_form_cu (attr); 82 break; 83 84 case DW_OP_call2: 85 case DW_OP_call4: 86 case DW_OP_call_ref: 87 { 88 Dwarf_Die die; 89 if (INTUSE(dwarf_getlocation_die) (attr, op, &die) != 0) 90 return -1; 91 if (INTUSE(dwarf_attr) (&die, DW_AT_location, result) == NULL) 92 { 93 __libdw_empty_loc_attr (result); 94 return 0; 95 } 96 } 97 break; 98 99 case DW_OP_GNU_implicit_pointer: 100 { 101 Dwarf_Die die; 102 if (INTUSE(dwarf_getlocation_die) (attr, op, &die) != 0) 103 return -1; 104 if (INTUSE(dwarf_attr) (&die, DW_AT_location, result) == NULL 105 && INTUSE(dwarf_attr) (&die, DW_AT_const_value, result) == NULL) 106 { 107 __libdw_empty_loc_attr (result); 108 return 0; 109 } 110 } 111 break; 112 113 default: 114 __libdw_seterrno (DWARF_E_INVALID_ACCESS); 115 return -1; 116 } 117 118 return 0; 119 } 120
