1/* Return scope DIEs containing PC address.
2   Copyright (C) 2005, 2007 Red Hat, Inc.
3   This file is part of Red Hat elfutils.
4
5   Red Hat elfutils is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by the
7   Free Software Foundation; version 2 of the License.
8
9   Red Hat elfutils is distributed in the hope that it will be useful, but
10   WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   General Public License for more details.
13
14   You should have received a copy of the GNU General Public License along
15   with Red Hat elfutils; if not, write to the Free Software Foundation,
16   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
17
18   In addition, as a special exception, Red Hat, Inc. gives You the
19   additional right to link the code of Red Hat elfutils with code licensed
20   under any Open Source Initiative certified open source license
21   (http://www.opensource.org/licenses/index.php) which requires the
22   distribution of source code with any binary distribution and to
23   distribute linked combinations of the two.  Non-GPL Code permitted under
24   this exception must only link to the code of Red Hat elfutils through
25   those well defined interfaces identified in the file named EXCEPTION
26   found in the source code files (the "Approved Interfaces").  The files
27   of Non-GPL Code may instantiate templates or use macros or inline
28   functions from the Approved Interfaces without causing the resulting
29   work to be covered by the GNU General Public License.  Only Red Hat,
30   Inc. may make changes or additions to the list of Approved Interfaces.
31   Red Hat's grant of this exception is conditioned upon your not adding
32   any new exceptions.  If you wish to add a new Approved Interface or
33   exception, please contact Red Hat.  You must obey the GNU General Public
34   License in all respects for all of the Red Hat elfutils code and other
35   code used in conjunction with Red Hat elfutils except the Non-GPL Code
36   covered by this exception.  If you modify this file, you may extend this
37   exception to your version of the file, but you are not obligated to do
38   so.  If you do not wish to provide this exception without modification,
39   you must delete this exception statement from your version and license
40   this file solely under the GPL without exception.
41
42   Red Hat elfutils is an included package of the Open Invention Network.
43   An included package of the Open Invention Network is a package for which
44   Open Invention Network licensees cross-license their patents.  No patent
45   license is granted, either expressly or impliedly, by designation as an
46   included package.  Should you wish to participate in the Open Invention
47   Network licensing program, please visit www.openinventionnetwork.com
48   <http://www.openinventionnetwork.com>.  */
49
50#ifdef HAVE_CONFIG_H
51# include <config.h>
52#endif
53
54#include <assert.h>
55#include <stdlib.h>
56#include "libdwP.h"
57#include <dwarf.h>
58
59
60struct args
61{
62  Dwarf_Addr pc;
63  Dwarf_Die *scopes;
64  unsigned int inlined, nscopes;
65  Dwarf_Die inlined_origin;
66};
67
68/* Preorder visitor: prune the traversal if this DIE does not contain PC.  */
69static int
70pc_match (unsigned int depth, struct Dwarf_Die_Chain *die, void *arg)
71{
72  struct args *a = arg;
73
74  if (a->scopes != NULL)
75    die->prune = true;
76  else
77    {
78      /* dwarf_haspc returns an error if there are no appropriate attributes.
79	 But we use it indiscriminantly instead of presuming which tags can
80	 have PC attributes.  So when it fails for that reason, treat it just
81	 as a nonmatching return.  */
82      int result = INTUSE(dwarf_haspc) (&die->die, a->pc);
83      if (result < 0)
84	{
85	  int error = INTUSE(dwarf_errno) ();
86	  if (error != DWARF_E_NOERROR && error != DWARF_E_NO_DEBUG_RANGES)
87	    {
88	      __libdw_seterrno (error);
89	      return -1;
90	    }
91	  result = 0;
92	}
93      if (result == 0)
94    	die->prune = true;
95
96      if (!die->prune
97	  && INTUSE (dwarf_tag) (&die->die) == DW_TAG_inlined_subroutine)
98	a->inlined = depth;
99    }
100
101  return 0;
102}
103
104/* Preorder visitor for second partial traversal after finding a
105   concrete inlined instance.  */
106static int
107origin_match (unsigned int depth, struct Dwarf_Die_Chain *die, void *arg)
108{
109  struct args *a = arg;
110
111  if (die->die.addr != a->inlined_origin.addr)
112    return 0;
113
114  /* We have a winner!  This is the abstract definition of the inline
115     function of which A->scopes[A->nscopes - 1] is a concrete instance.
116  */
117
118  unsigned int nscopes = a->nscopes + depth;
119  Dwarf_Die *scopes = realloc (a->scopes, nscopes * sizeof scopes[0]);
120  if (scopes == NULL)
121    {
122      free (a->scopes);
123      __libdw_seterrno (DWARF_E_NOMEM);
124      return -1;
125    }
126
127  a->scopes = scopes;
128  do
129    {
130      die = die->parent;
131      scopes[a->nscopes++] = die->die;
132    }
133  while (a->nscopes < nscopes);
134  assert (die->parent == NULL);
135  return a->nscopes;
136}
137
138/* Postorder visitor: first (innermost) call wins.  */
139static int
140pc_record (unsigned int depth, struct Dwarf_Die_Chain *die, void *arg)
141{
142  struct args *a = arg;
143
144  if (die->prune)
145    return 0;
146
147  if (a->scopes == NULL)
148    {
149      /* We have hit the innermost DIE that contains the target PC.  */
150
151      a->nscopes = depth + 1 - a->inlined;
152      a->scopes = malloc (a->nscopes * sizeof a->scopes[0]);
153      if (a->scopes == NULL)
154	{
155	  __libdw_seterrno (DWARF_E_NOMEM);
156	  return -1;
157	}
158
159      for (unsigned int i = 0; i < a->nscopes; ++i)
160	{
161	  a->scopes[i] = die->die;
162	  die = die->parent;
163	}
164
165      if (a->inlined == 0)
166	{
167	  assert (die == NULL);
168	  return a->nscopes;
169	}
170
171      /* This is the concrete inlined instance itself.
172	 Record its abstract_origin pointer.  */
173      Dwarf_Die *const inlinedie = &a->scopes[depth - a->inlined];
174
175      assert (INTUSE (dwarf_tag) (inlinedie) == DW_TAG_inlined_subroutine);
176      Dwarf_Attribute attr_mem;
177      Dwarf_Attribute *attr = INTUSE (dwarf_attr) (inlinedie,
178						   DW_AT_abstract_origin,
179						   &attr_mem);
180      if (INTUSE (dwarf_formref_die) (attr, &a->inlined_origin) == NULL)
181	return -1;
182      return 0;
183    }
184
185
186  /* We've recorded the scopes back to one that is a concrete inlined
187     instance.  Now return out of the traversal back to the scope
188     containing that instance.  */
189
190  assert (a->inlined);
191  if (depth >= a->inlined)
192    /* Not there yet.  */
193    return 0;
194
195  /* Now we are in a scope that contains the concrete inlined instance.
196     Search it for the inline function's abstract definition.
197     If we don't find it, return to search the containing scope.
198     If we do find it, the nonzero return value will bail us out
199     of the postorder traversal.  */
200  return __libdw_visit_scopes (depth, die, &origin_match, NULL, a);
201}
202
203
204int
205dwarf_getscopes (Dwarf_Die *cudie, Dwarf_Addr pc, Dwarf_Die **scopes)
206{
207  if (cudie == NULL)
208    return -1;
209
210  struct Dwarf_Die_Chain cu = { .parent = NULL, .die = *cudie };
211  struct args a = { .pc = pc };
212
213  int result = __libdw_visit_scopes (0, &cu, &pc_match, &pc_record, &a);
214
215  if (result == 0 && a.scopes != NULL)
216    result = __libdw_visit_scopes (0, &cu, &origin_match, NULL, &a);
217
218  if (result > 0)
219    *scopes = a.scopes;
220
221  return result;
222}
223