1/* Get function information.
2   Copyright (C) 2005, 2013, 2015 Red Hat, Inc.
3   This file is part of elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2005.
5
6   This file is free software; you can redistribute it and/or modify
7   it under the terms of either
8
9     * the GNU Lesser General Public License as published by the Free
10       Software Foundation; either version 3 of the License, or (at
11       your option) any later version
12
13   or
14
15     * the GNU General Public License as published by the Free
16       Software Foundation; either version 2 of the License, or (at
17       your option) any later version
18
19   or both in parallel, as here.
20
21   elfutils is distributed in the hope that it will be useful, but
22   WITHOUT ANY WARRANTY; without even the implied warranty of
23   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24   General Public License for more details.
25
26   You should have received copies of the GNU General Public License and
27   the GNU Lesser General Public License along with this program.  If
28   not, see <http://www.gnu.org/licenses/>.  */
29
30#ifdef HAVE_CONFIG_H
31# include <config.h>
32#endif
33
34#include <dwarf.h>
35#include "libdwP.h"
36
37
38struct visitor_info
39{
40  /* The user callback of dwarf_getfuncs.  */
41  int (*callback) (Dwarf_Die *, void *);
42
43  /* The user arg value to dwarf_getfuncs.  */
44  void *arg;
45
46  /* Addr of the DIE offset where to (re)start the search.  Zero for all.  */
47  void *start_addr;
48
49  /* Last subprogram DIE addr seen.  */
50  void *last_addr;
51
52  /* The CU only contains C functions.  Allows pruning of most subtrees.  */
53  bool c_cu;
54};
55
56static int
57tree_visitor (unsigned int depth __attribute__ ((unused)),
58	      struct Dwarf_Die_Chain *chain, void *arg)
59{
60  struct visitor_info *const v = arg;
61  Dwarf_Die *die = &chain->die;
62  void *start_addr = v->start_addr;
63  void *die_addr = die->addr;
64
65  /* Pure C CUs can only contain defining subprogram DIEs as direct
66     children of the CU DIE or as nested function inside a normal C
67     code constructs.  */
68  int tag = INTUSE(dwarf_tag) (die);
69  if (v->c_cu
70      && tag != DW_TAG_subprogram
71      && tag != DW_TAG_lexical_block
72      && tag != DW_TAG_inlined_subroutine)
73    {
74      chain->prune = true;
75      return DWARF_CB_OK;
76    }
77
78  /* Skip all DIEs till we found the (re)start addr.  */
79  if (start_addr != NULL)
80    {
81      if (die_addr == start_addr)
82	v->start_addr = NULL;
83      return DWARF_CB_OK;
84    }
85
86  /* If this isn't a (defining) subprogram entity, skip DIE.  */
87  if (tag != DW_TAG_subprogram
88      || INTUSE(dwarf_hasattr) (die, DW_AT_declaration))
89    return DWARF_CB_OK;
90
91  v->last_addr = die_addr;
92  return (*v->callback) (die, v->arg);
93}
94
95ptrdiff_t
96dwarf_getfuncs (Dwarf_Die *cudie, int (*callback) (Dwarf_Die *, void *),
97		void *arg, ptrdiff_t offset)
98{
99  if (unlikely (cudie == NULL
100		|| INTUSE(dwarf_tag) (cudie) != DW_TAG_compile_unit))
101    return -1;
102
103  int lang = INTUSE(dwarf_srclang) (cudie);
104  bool c_cu = (lang == DW_LANG_C89
105	       || lang == DW_LANG_C
106	       || lang == DW_LANG_C99
107	       || lang == DW_LANG_C11);
108
109  struct visitor_info v = { callback, arg, (void *) offset, NULL, c_cu };
110  struct Dwarf_Die_Chain chain = { .die = CUDIE (cudie->cu),
111				   .parent = NULL };
112  int res = __libdw_visit_scopes (0, &chain, NULL, &tree_visitor, NULL, &v);
113
114  if (res == DWARF_CB_ABORT)
115    return (ptrdiff_t) v.last_addr;
116  else
117    return res;
118}
119