1 /* Find a named variable or parameter within given scopes.
2 Copyright (C) 2005-2009 Red Hat, Inc.
3 This file is part of elfutils.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
7
8 * the GNU Lesser General Public License as published by the Free
9 Software Foundation; either version 3 of the License, or (at
10 your option) any later version
11
12 or
13
14 * the GNU General Public License as published by the Free
15 Software Foundation; either version 2 of the License, or (at
16 your option) any later version
17
18 or both in parallel, as here.
19
20 elfutils is distributed in the hope that it will be useful, but
21 WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 General Public License for more details.
24
25 You should have received copies of the GNU General Public License and
26 the GNU Lesser General Public License along with this program. If
27 not, see <http://www.gnu.org/licenses/>. */
28
29 #ifdef HAVE_CONFIG_H
30 # include <config.h>
31 #endif
32
33 #include <stdbool.h>
34 #include <string.h>
35 #include "libdwP.h"
36 #include <dwarf.h>
37
38
39 /* Find the containing CU's files. */
40 static int
getfiles(Dwarf_Die * die,Dwarf_Files ** files)41 getfiles (Dwarf_Die *die, Dwarf_Files **files)
42 {
43 return INTUSE(dwarf_getsrcfiles) (&CUDIE (die->cu), files, NULL);
44 }
45
46 /* Fetch an attribute that should have a constant integer form. */
47 static int
getattr(Dwarf_Die * die,int search_name,Dwarf_Word * value)48 getattr (Dwarf_Die *die, int search_name, Dwarf_Word *value)
49 {
50 Dwarf_Attribute attr_mem;
51 return INTUSE(dwarf_formudata) (INTUSE(dwarf_attr) (die, search_name,
52 &attr_mem), value);
53 }
54
55 /* Search SCOPES[0..NSCOPES-1] for a variable called NAME.
56 Ignore the first SKIP_SHADOWS scopes that match the name.
57 If MATCH_FILE is not null, accept only declaration in that source file;
58 if MATCH_LINENO or MATCH_LINECOL are also nonzero, accept only declaration
59 at that line and column.
60
61 If successful, fill in *RESULT with the DIE of the variable found,
62 and return N where SCOPES[N] is the scope defining the variable.
63 Return -1 for errors or -2 for no matching variable found. */
64
65 int
dwarf_getscopevar(Dwarf_Die * scopes,int nscopes,const char * name,int skip_shadows,const char * match_file,int match_lineno,int match_linecol,Dwarf_Die * result)66 dwarf_getscopevar (Dwarf_Die *scopes, int nscopes,
67 const char *name, int skip_shadows,
68 const char *match_file, int match_lineno, int match_linecol,
69 Dwarf_Die *result)
70 {
71 /* Match against the given file name. */
72 size_t match_file_len = match_file == NULL ? 0 : strlen (match_file);
73 bool lastfile_matches = false;
74 const char *lastfile = NULL;
75 inline bool file_matches (Dwarf_Files *files, size_t idx)
76 {
77 if (idx >= files->nfiles)
78 return false;
79
80 const char *file = files->info[idx].name;
81 if (file != lastfile)
82 {
83 size_t len = strlen (file);
84 lastfile_matches = (len >= match_file_len
85 && !memcmp (match_file, file, match_file_len)
86 && (len == match_file_len
87 || file[len - match_file_len - 1] == '/'));
88 }
89 return lastfile_matches;
90 }
91
92 /* Start with the innermost scope and move out. */
93 for (int out = 0; out < nscopes; ++out)
94 if (INTUSE(dwarf_haschildren) (&scopes[out]))
95 {
96 if (INTUSE(dwarf_child) (&scopes[out], result) != 0)
97 return -1;
98 do
99 {
100 switch (INTUSE(dwarf_tag) (result))
101 {
102 case DW_TAG_variable:
103 case DW_TAG_formal_parameter:
104 break;
105
106 default:
107 continue;
108 }
109
110 /* Only get here for a variable or parameter. Check the name. */
111 const char *diename = INTUSE(dwarf_diename) (result);
112 if (diename != NULL && !strcmp (name, diename))
113 {
114 /* We have a matching name. */
115
116 if (skip_shadows > 0)
117 {
118 /* Punt this scope for the one it shadows. */
119 --skip_shadows;
120 break;
121 }
122
123 if (match_file != NULL)
124 {
125 /* Check its decl_file. */
126
127 Dwarf_Word i;
128 Dwarf_Files *files;
129 if (getattr (result, DW_AT_decl_file, &i) != 0
130 || getfiles (&scopes[out], &files) != 0)
131 break;
132
133 if (!file_matches (files, i))
134 break;
135
136 if (match_lineno > 0
137 && (getattr (result, DW_AT_decl_line, &i) != 0
138 || (int) i != match_lineno))
139 break;
140 if (match_linecol > 0
141 && (getattr (result, DW_AT_decl_column, &i) != 0
142 || (int) i != match_linecol))
143 break;
144 }
145
146 /* We have a winner! */
147 return out;
148 }
149 }
150 while (INTUSE(dwarf_siblingof) (result, result) == 0);
151 }
152
153 return -2;
154 }
155