1/* Find CU for given offset.
2   Copyright (C) 2003-2010 Red Hat, Inc.
3   This file is part of Red Hat elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2003.
5
6   Red Hat elfutils is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by the
8   Free Software Foundation; version 2 of the License.
9
10   Red Hat elfutils is distributed in the hope that it will be useful, but
11   WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   General Public License for more details.
14
15   You should have received a copy of the GNU General Public License along
16   with Red Hat elfutils; if not, write to the Free Software Foundation,
17   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
18
19   In addition, as a special exception, Red Hat, Inc. gives You the
20   additional right to link the code of Red Hat elfutils with code licensed
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37   covered by this exception.  If you modify this file, you may extend this
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40   you must delete this exception statement from your version and license
41   this file solely under the GPL without exception.
42
43   Red Hat elfutils is an included package of the Open Invention Network.
44   An included package of the Open Invention Network is a package for which
45   Open Invention Network licensees cross-license their patents.  No patent
46   license is granted, either expressly or impliedly, by designation as an
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49   <http://www.openinventionnetwork.com>.  */
50
51#ifdef HAVE_CONFIG_H
52# include <config.h>
53#endif
54
55#include <assert.h>
56#include <search.h>
57#include "libdwP.h"
58
59
60struct Dwarf_CU *
61internal_function
62__libdw_intern_next_unit (dbg, debug_types)
63     Dwarf *dbg;
64     bool debug_types;
65{
66  Dwarf_Off *const offsetp
67    = debug_types ? &dbg->next_tu_offset : &dbg->next_cu_offset;
68
69  Dwarf_Off oldoff = *offsetp;
70  uint16_t version;
71  uint8_t address_size;
72  uint8_t offset_size;
73  Dwarf_Off abbrev_offset;
74  uint64_t type_sig8 = 0;
75  Dwarf_Off type_offset = 0;
76
77  if (INTUSE(dwarf_next_unit) (dbg, oldoff, offsetp, NULL,
78			       &version, &abbrev_offset,
79			       &address_size, &offset_size,
80			       debug_types ? &type_sig8 : NULL,
81			       debug_types ? &type_offset : NULL) != 0)
82    /* No more entries.  */
83    return NULL;
84
85  /* We only know how to handle the DWARF version 2 through 4 formats.  */
86  if (unlikely (version < 2) || unlikely (version > 4))
87    {
88      __libdw_seterrno (DWARF_E_INVALID_DWARF);
89      return NULL;
90    }
91
92  /* Create an entry for this CU.  */
93  struct Dwarf_CU *newp = libdw_typed_alloc (dbg, struct Dwarf_CU);
94
95  newp->dbg = dbg;
96  newp->start = oldoff;
97  newp->end = *offsetp;
98  newp->address_size = address_size;
99  newp->offset_size = offset_size;
100  newp->version = version;
101  newp->type_sig8 = type_sig8;
102  newp->type_offset = type_offset;
103  Dwarf_Abbrev_Hash_init (&newp->abbrev_hash, 41);
104  newp->orig_abbrev_offset = newp->last_abbrev_offset = abbrev_offset;
105  newp->lines = NULL;
106  newp->locs = NULL;
107
108  return newp;
109}
110
111
112static int
113findcu_cb (const void *arg1, const void *arg2)
114{
115  struct Dwarf_CU *cu1 = (struct Dwarf_CU *) arg1;
116  struct Dwarf_CU *cu2 = (struct Dwarf_CU *) arg2;
117
118  /* Find out which of the two arguments is the search value.  It has
119     end offset 0.  */
120  if (cu1->end == 0)
121    {
122      if (cu1->start < cu2->start)
123	return -1;
124      if (cu1->start >= cu2->end)
125	return 1;
126    }
127  else
128    {
129      if (cu2->start < cu1->start)
130	return 1;
131      if (cu2->start >= cu1->end)
132	return -1;
133    }
134
135  return 0;
136}
137
138struct Dwarf_CU *
139__libdw_findcu (dbg, start, debug_types)
140     Dwarf *dbg;
141     Dwarf_Off start;
142     bool debug_types;
143{
144  void **tree = debug_types ? &dbg->tu_tree : &dbg->cu_tree;
145  Dwarf_Off *next_offset
146    = debug_types ? &dbg->next_tu_offset : &dbg->next_cu_offset;
147
148  /* Maybe we already know that CU.  */
149  struct Dwarf_CU fake = { .start = start, .end = 0 };
150  struct Dwarf_CU **found = tfind (&fake, tree, findcu_cb);
151  if (found != NULL)
152    return *found;
153
154  if (start < *next_offset)
155    {
156      __libdw_seterrno (DWARF_E_INVALID_DWARF);
157      return NULL;
158    }
159
160  /* No.  Then read more CUs.  */
161  while (1)
162    {
163      Dwarf_Off oldoff = *next_offset;
164      struct Dwarf_CU *newp = __libdw_intern_next_unit (dbg, debug_types);
165      if (newp == NULL)
166	return NULL;
167
168      /* Add the new entry to the search tree.  */
169      if (tsearch (newp, tree, findcu_cb) == NULL)
170	{
171	  /* Something went wrong.  Undo the operation.  */
172	  *next_offset = oldoff;
173	  __libdw_seterrno (DWARF_E_NOMEM);
174	  return NULL;
175	}
176
177      /* Is this the one we are looking for?  */
178      if (start < *next_offset)
179	// XXX Match exact offset.
180	return newp;
181    }
182  /* NOTREACHED */
183}
184