1 /* Get abbreviation at given offset. 2 Copyright (C) 2003, 2004 Red Hat, Inc. 3 Written by Ulrich Drepper <drepper (at) redhat.com>, 2003. 4 5 This program is Open Source software; you can redistribute it and/or 6 modify it under the terms of the Open Software License version 1.0 as 7 published by the Open Source Initiative. 8 9 You should have received a copy of the Open Software License along 10 with this program; if not, you may obtain a copy of the Open Software 11 License version 1.0 from http://www.opensource.org/licenses/osl.php or 12 by writing the Open Source Initiative c/o Lawrence Rosen, Esq., 13 3001 King Ranch Road, Ukiah, CA 95482. */ 14 15 #ifdef HAVE_CONFIG_H 16 # include <config.h> 17 #endif 18 19 #include <assert.h> 20 #include <dwarf.h> 21 #include "libdwP.h" 22 23 24 Dwarf_Abbrev * 25 internal_function_def 26 __libdw_getabbrev (dbg, cu, offset, lengthp, result) 27 Dwarf *dbg; 28 struct Dwarf_CU *cu; 29 Dwarf_Off offset; 30 size_t *lengthp; 31 Dwarf_Abbrev *result; 32 { 33 /* Don't fail if there is not .debug_abbrev section. */ 34 if (dbg->sectiondata[IDX_debug_abbrev] == NULL) 35 return NULL; 36 37 unsigned char *abbrevp 38 = (unsigned char *) dbg->sectiondata[IDX_debug_abbrev]->d_buf + offset; 39 if (*abbrevp == '\0') 40 /* We are past the last entry. */ 41 return NULL; 42 43 /* 7.5.3 Abbreviations Tables 44 45 [...] Each declaration begins with an unsigned LEB128 number 46 representing the abbreviation code itself. [...] The 47 abbreviation code is followed by another unsigned LEB128 48 number that encodes the entry's tag. [...] 49 50 [...] Following the tag encoding is a 1-byte value that 51 determines whether a debugging information entry using this 52 abbreviation has child entries or not. [...] 53 54 [...] Finally, the child encoding is followed by a series of 55 attribute specifications. Each attribute specification 56 consists of two parts. The first part is an unsigned LEB128 57 number representing the attribute's name. The second part is 58 an unsigned LEB128 number representing the attribute's form. */ 59 unsigned char *start_abbrevp = abbrevp; 60 unsigned int code; 61 get_uleb128 (code, abbrevp); 62 63 /* Check whether this code is already in the hash table. */ 64 bool foundit = false; 65 Dwarf_Abbrev *abb = NULL; 66 if (cu == NULL 67 || (abb = Dwarf_Abbrev_Hash_find (&cu->abbrev_hash, code, NULL)) == NULL) 68 { 69 if (result == NULL) 70 abb = libdw_typed_alloc (dbg, Dwarf_Abbrev); 71 else 72 abb = result; 73 } 74 else 75 { 76 foundit = true; 77 78 assert (abb->offset == offset); 79 80 /* If the caller doesn't need the length we are done. */ 81 if (lengthp == NULL) 82 goto out; 83 } 84 85 /* If there is already a value in the hash table we are going to 86 overwrite its content. This must not be a problem, since the 87 content better be the same. */ 88 abb->code = code; 89 get_uleb128 (abb->tag, abbrevp); 90 abb->has_children = *abbrevp++ == DW_CHILDREN_yes; 91 abb->attrp = abbrevp; 92 abb->offset = offset; 93 94 /* Skip over all the attributes and count them while doing so. */ 95 abb->attrcnt = 0; 96 unsigned int attrname; 97 unsigned int attrform; 98 do 99 { 100 get_uleb128 (attrname, abbrevp); 101 get_uleb128 (attrform, abbrevp); 102 } 103 while (attrname != 0 && attrform != 0 && ++abb->attrcnt); 104 105 /* Return the length to the caller if she asked for it. */ 106 if (lengthp != NULL) 107 *lengthp = abbrevp - start_abbrevp; 108 109 /* Add the entry to the hash table. */ 110 if (cu != NULL && ! foundit) 111 (void) Dwarf_Abbrev_Hash_insert (&cu->abbrev_hash, abb->code, abb); 112 113 out: 114 return abb; 115 } 116 117 118 Dwarf_Abbrev * 119 dwarf_getabbrev (die, offset, lengthp) 120 Dwarf_Die *die; 121 Dwarf_Off offset; 122 size_t *lengthp; 123 { 124 return __libdw_getabbrev (die->cu->dbg, die->cu, 125 die->cu->orig_abbrev_offset + offset, lengthp, 126 NULL); 127 } 128
