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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 
38 struct 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 
56 static int
tree_visitor(unsigned int depth,struct Dwarf_Die_Chain * chain,void * arg)57 tree_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 
95 ptrdiff_t
dwarf_getfuncs(Dwarf_Die * cudie,int (* callback)(Dwarf_Die *,void *),void * arg,ptrdiff_t offset)96 dwarf_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