xref: /freebsd/contrib/elftoolchain/libdwarf/libdwarf_abbrev.c (revision af23369a6deaaeb612ab266eb88b8bb8d560c322)
1 /*-
2  * Copyright (c) 2007 John Birrell (jb@freebsd.org)
3  * Copyright (c) 2009-2011 Kai Wang
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include "_libdwarf.h"
29 
30 ELFTC_VCSID("$Id: libdwarf_abbrev.c 3420 2016-02-27 02:14:05Z emaste $");
31 
32 int
33 _dwarf_abbrev_add(Dwarf_CU cu, uint64_t entry, uint64_t tag, uint8_t children,
34     uint64_t aboff, Dwarf_Abbrev *abp, Dwarf_Error *error)
35 {
36 	Dwarf_Abbrev ab;
37 	Dwarf_Debug dbg;
38 
39 	dbg = cu != NULL ? cu->cu_dbg : NULL;
40 
41 	if ((ab = malloc(sizeof(struct _Dwarf_Abbrev))) == NULL) {
42 		DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
43 		return (DW_DLE_MEMORY);
44 	}
45 
46 	/* Initialise the abbrev structure. */
47 	ab->ab_entry	= entry;
48 	ab->ab_tag	= tag;
49 	ab->ab_children	= children;
50 	ab->ab_offset	= aboff;
51 	ab->ab_length	= 0;	/* fill in later. */
52 	ab->ab_atnum	= 0;	/* fill in later. */
53 
54 	/* Initialise the list of attribute definitions. */
55 	STAILQ_INIT(&ab->ab_attrdef);
56 
57 	/* Add the abbrev to the hash table of the compilation unit. */
58 	if (cu != NULL)
59 		HASH_ADD(ab_hh, cu->cu_abbrev_hash, ab_entry,
60 		    sizeof(ab->ab_entry), ab);
61 
62 	*abp = ab;
63 	return (DW_DLE_NONE);
64 }
65 
66 int
67 _dwarf_attrdef_add(Dwarf_Debug dbg, Dwarf_Abbrev ab, uint64_t attr,
68     uint64_t form, uint64_t adoff, Dwarf_AttrDef *adp, Dwarf_Error *error)
69 {
70 	Dwarf_AttrDef ad;
71 
72 	if (ab == NULL) {
73 		DWARF_SET_ERROR(dbg, error, DW_DLE_ARGUMENT);
74 		return (DW_DLE_ARGUMENT);
75 	}
76 
77 	if ((ad = malloc(sizeof(struct _Dwarf_AttrDef))) == NULL) {
78 		DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
79 		return (DW_DLE_MEMORY);
80 	}
81 
82 	/* Initialise the attribute definition structure. */
83 	ad->ad_attrib	= attr;
84 	ad->ad_form	= form;
85 	ad->ad_offset	= adoff;
86 
87 	/* Add the attribute definition to the list in the abbrev. */
88 	STAILQ_INSERT_TAIL(&ab->ab_attrdef, ad, ad_next);
89 
90 	/* Increase number of attribute counter. */
91 	ab->ab_atnum++;
92 
93 	if (adp != NULL)
94 		*adp = ad;
95 
96 	return (DW_DLE_NONE);
97 }
98 
99 int
100 _dwarf_abbrev_parse(Dwarf_Debug dbg, Dwarf_CU cu, Dwarf_Unsigned *offset,
101     Dwarf_Abbrev *abp, Dwarf_Error *error)
102 {
103 	Dwarf_Section *ds;
104 	uint64_t attr;
105 	uint64_t entry;
106 	uint64_t form;
107 	uint64_t aboff;
108 	uint64_t adoff;
109 	uint64_t tag;
110 	uint8_t children;
111 	int ret;
112 
113 	assert(abp != NULL);
114 
115 	ds = _dwarf_find_section(dbg, ".debug_abbrev");
116 	if (ds == NULL || *offset >= ds->ds_size)
117 		return (DW_DLE_NO_ENTRY);
118 
119 	aboff = *offset;
120 
121 	entry = _dwarf_read_uleb128(ds->ds_data, offset);
122 	if (entry == 0) {
123 		/* Last entry. */
124 		ret = _dwarf_abbrev_add(cu, entry, 0, 0, aboff, abp,
125 		    error);
126 		if (ret == DW_DLE_NONE) {
127 			(*abp)->ab_length = 1;
128 			return (ret);
129 		} else
130 			return (ret);
131 	}
132 	tag = _dwarf_read_uleb128(ds->ds_data, offset);
133 	children = dbg->read(ds->ds_data, offset, 1);
134 	if ((ret = _dwarf_abbrev_add(cu, entry, tag, children, aboff,
135 	    abp, error)) != DW_DLE_NONE)
136 		return (ret);
137 
138 	/* Parse attribute definitions. */
139 	do {
140 		adoff = *offset;
141 		attr = _dwarf_read_uleb128(ds->ds_data, offset);
142 		form = _dwarf_read_uleb128(ds->ds_data, offset);
143 		if (attr != 0)
144 			if ((ret = _dwarf_attrdef_add(dbg, *abp, attr,
145 			    form, adoff, NULL, error)) != DW_DLE_NONE)
146 				return (ret);
147 	} while (attr != 0);
148 
149 	(*abp)->ab_length = *offset - aboff;
150 
151 	return (ret);
152 }
153 
154 int
155 _dwarf_abbrev_find(Dwarf_CU cu, uint64_t entry, Dwarf_Abbrev *abp,
156     Dwarf_Error *error)
157 {
158 	Dwarf_Abbrev ab;
159 	Dwarf_Section *ds;
160 	Dwarf_Unsigned offset;
161 	int ret;
162 
163 	if (entry == 0)
164 		return (DW_DLE_NO_ENTRY);
165 
166 	/* Check if the desired abbrev entry is already in the hash table. */
167 	HASH_FIND(ab_hh, cu->cu_abbrev_hash, &entry, sizeof(entry), ab);
168 	if (ab != NULL) {
169 		*abp = ab;
170 		return (DW_DLE_NONE);
171 	}
172 
173 	if (cu->cu_abbrev_loaded) {
174 		return (DW_DLE_NO_ENTRY);
175 	}
176 
177 	/* Load and search the abbrev table. */
178 	ds = _dwarf_find_section(cu->cu_dbg, ".debug_abbrev");
179 	if (ds == NULL)
180 		return (DW_DLE_NO_ENTRY);
181 
182 	offset = cu->cu_abbrev_offset_cur;
183 	while (offset < ds->ds_size) {
184 		ret = _dwarf_abbrev_parse(cu->cu_dbg, cu, &offset, &ab, error);
185 		if (ret != DW_DLE_NONE)
186 			return (ret);
187 		if (ab->ab_entry == entry) {
188 			cu->cu_abbrev_offset_cur = offset;
189 			*abp = ab;
190 			return (DW_DLE_NONE);
191 		}
192 		if (ab->ab_entry == 0) {
193 			cu->cu_abbrev_offset_cur = offset;
194 			cu->cu_abbrev_loaded = 1;
195 			break;
196 		}
197 	}
198 
199 	return (DW_DLE_NO_ENTRY);
200 }
201 
202 void
203 _dwarf_abbrev_cleanup(Dwarf_CU cu)
204 {
205 	Dwarf_Abbrev ab, tab;
206 	Dwarf_AttrDef ad, tad;
207 
208 	assert(cu != NULL);
209 
210 	HASH_ITER(ab_hh, cu->cu_abbrev_hash, ab, tab) {
211 		HASH_DELETE(ab_hh, cu->cu_abbrev_hash, ab);
212 		STAILQ_FOREACH_SAFE(ad, &ab->ab_attrdef, ad_next, tad) {
213 			STAILQ_REMOVE(&ab->ab_attrdef, ad, _Dwarf_AttrDef,
214 			    ad_next);
215 			free(ad);
216 		}
217 		free(ab);
218 	}
219 }
220 
221 int
222 _dwarf_abbrev_gen(Dwarf_P_Debug dbg, Dwarf_Error *error)
223 {
224 	Dwarf_CU cu;
225 	Dwarf_Abbrev ab;
226 	Dwarf_AttrDef ad;
227 	Dwarf_P_Section ds;
228 	int ret;
229 
230 	cu = STAILQ_FIRST(&dbg->dbg_cu);
231 	if (cu == NULL)
232 		return (DW_DLE_NONE);
233 
234 	/* Create .debug_abbrev section. */
235 	if ((ret = _dwarf_section_init(dbg, &ds, ".debug_abbrev", 0, error)) !=
236 	    DW_DLE_NONE)
237 		return (ret);
238 
239 	for (ab = cu->cu_abbrev_hash; ab != NULL; ab = ab->ab_hh.next) {
240 		RCHECK(WRITE_ULEB128(ab->ab_entry));
241 		RCHECK(WRITE_ULEB128(ab->ab_tag));
242 		RCHECK(WRITE_VALUE(ab->ab_children, 1));
243 		STAILQ_FOREACH(ad, &ab->ab_attrdef, ad_next) {
244 			RCHECK(WRITE_ULEB128(ad->ad_attrib));
245 			RCHECK(WRITE_ULEB128(ad->ad_form));
246 		}
247 		/* Signal end of attribute spec list. */
248 		RCHECK(WRITE_ULEB128(0));
249 		RCHECK(WRITE_ULEB128(0));
250 	}
251 	/* End of abbreviation for this CU. */
252 	RCHECK(WRITE_ULEB128(0));
253 
254 	/* Notify the creation of .debug_abbrev ELF section. */
255 	RCHECK(_dwarf_section_callback(dbg, ds, SHT_PROGBITS, 0, 0, 0, error));
256 
257 	return (DW_DLE_NONE);
258 
259 gen_fail:
260 
261 	_dwarf_section_free(dbg, &ds);
262 
263 	return (ret);
264 }
265