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316afdb1 | 1 | /* C declarator syntax glue. |
250d07de | 2 | Copyright (C) 2019-2021 Free Software Foundation, Inc. |
316afdb1 NA |
3 | |
4 | This file is part of libctf. | |
5 | ||
6 | libctf is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
8 | Software Foundation; either version 3, or (at your option) any later | |
9 | version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
14 | See the GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; see the file COPYING. If not see | |
18 | <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | /* CTF Declaration Stack | |
21 | ||
22 | In order to implement ctf_type_name(), we must convert a type graph back | |
23 | into a C type declaration. Unfortunately, a type graph represents a storage | |
24 | class ordering of the type whereas a type declaration must obey the C rules | |
25 | for operator precedence, and the two orderings are frequently in conflict. | |
26 | For example, consider these CTF type graphs and their C declarations: | |
27 | ||
28 | CTF_K_POINTER -> CTF_K_FUNCTION -> CTF_K_INTEGER : int (*)() | |
29 | CTF_K_POINTER -> CTF_K_ARRAY -> CTF_K_INTEGER : int (*)[] | |
30 | ||
31 | In each case, parentheses are used to raise operator * to higher lexical | |
32 | precedence, so the string form of the C declaration cannot be constructed by | |
33 | walking the type graph links and forming the string from left to right. | |
34 | ||
35 | The functions in this file build a set of stacks from the type graph nodes | |
36 | corresponding to the C operator precedence levels in the appropriate order. | |
37 | The code in ctf_type_name() can then iterate over the levels and nodes in | |
38 | lexical precedence order and construct the final C declaration string. */ | |
39 | ||
40 | #include <ctf-impl.h> | |
41 | #include <string.h> | |
42 | ||
43 | void | |
44 | ctf_decl_init (ctf_decl_t *cd) | |
45 | { | |
46 | int i; | |
47 | ||
48 | memset (cd, 0, sizeof (ctf_decl_t)); | |
49 | ||
50 | for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++) | |
51 | cd->cd_order[i] = CTF_PREC_BASE - 1; | |
52 | ||
53 | cd->cd_qualp = CTF_PREC_BASE; | |
54 | cd->cd_ordp = CTF_PREC_BASE; | |
55 | } | |
56 | ||
57 | void | |
58 | ctf_decl_fini (ctf_decl_t *cd) | |
59 | { | |
60 | ctf_decl_node_t *cdp, *ndp; | |
61 | int i; | |
62 | ||
63 | for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++) | |
64 | { | |
65 | for (cdp = ctf_list_next (&cd->cd_nodes[i]); cdp != NULL; cdp = ndp) | |
66 | { | |
67 | ndp = ctf_list_next (cdp); | |
de07e349 | 68 | free (cdp); |
316afdb1 NA |
69 | } |
70 | } | |
b255b35f | 71 | free (cd->cd_buf); |
316afdb1 NA |
72 | } |
73 | ||
74 | void | |
139633c3 | 75 | ctf_decl_push (ctf_decl_t *cd, ctf_dict_t *fp, ctf_id_t type) |
316afdb1 NA |
76 | { |
77 | ctf_decl_node_t *cdp; | |
78 | ctf_decl_prec_t prec; | |
79 | uint32_t kind, n = 1; | |
80 | int is_qual = 0; | |
81 | ||
82 | const ctf_type_t *tp; | |
83 | ctf_arinfo_t ar; | |
84 | ||
85 | if ((tp = ctf_lookup_by_id (&fp, type)) == NULL) | |
86 | { | |
87 | cd->cd_err = fp->ctf_errno; | |
88 | return; | |
89 | } | |
90 | ||
91 | switch (kind = LCTF_INFO_KIND (fp, tp->ctt_info)) | |
92 | { | |
93 | case CTF_K_ARRAY: | |
94 | (void) ctf_array_info (fp, type, &ar); | |
95 | ctf_decl_push (cd, fp, ar.ctr_contents); | |
96 | n = ar.ctr_nelems; | |
97 | prec = CTF_PREC_ARRAY; | |
98 | break; | |
99 | ||
100 | case CTF_K_TYPEDEF: | |
101 | if (ctf_strptr (fp, tp->ctt_name)[0] == '\0') | |
102 | { | |
103 | ctf_decl_push (cd, fp, tp->ctt_type); | |
104 | return; | |
105 | } | |
106 | prec = CTF_PREC_BASE; | |
107 | break; | |
108 | ||
109 | case CTF_K_FUNCTION: | |
110 | ctf_decl_push (cd, fp, tp->ctt_type); | |
111 | prec = CTF_PREC_FUNCTION; | |
112 | break; | |
113 | ||
114 | case CTF_K_POINTER: | |
115 | ctf_decl_push (cd, fp, tp->ctt_type); | |
116 | prec = CTF_PREC_POINTER; | |
117 | break; | |
118 | ||
119 | case CTF_K_SLICE: | |
120 | ctf_decl_push (cd, fp, ctf_type_reference (fp, type)); | |
121 | prec = CTF_PREC_BASE; | |
122 | break; | |
123 | ||
124 | case CTF_K_VOLATILE: | |
125 | case CTF_K_CONST: | |
126 | case CTF_K_RESTRICT: | |
127 | ctf_decl_push (cd, fp, tp->ctt_type); | |
128 | prec = cd->cd_qualp; | |
129 | is_qual++; | |
130 | break; | |
131 | ||
132 | default: | |
133 | prec = CTF_PREC_BASE; | |
134 | } | |
135 | ||
de07e349 | 136 | if ((cdp = malloc (sizeof (ctf_decl_node_t))) == NULL) |
316afdb1 NA |
137 | { |
138 | cd->cd_err = EAGAIN; | |
139 | return; | |
140 | } | |
141 | ||
142 | cdp->cd_type = type; | |
143 | cdp->cd_kind = kind; | |
144 | cdp->cd_n = n; | |
145 | ||
146 | if (ctf_list_next (&cd->cd_nodes[prec]) == NULL) | |
147 | cd->cd_order[prec] = cd->cd_ordp++; | |
148 | ||
149 | /* Reset cd_qualp to the highest precedence level that we've seen so | |
150 | far that can be qualified (CTF_PREC_BASE or CTF_PREC_POINTER). */ | |
151 | ||
152 | if (prec > cd->cd_qualp && prec < CTF_PREC_ARRAY) | |
153 | cd->cd_qualp = prec; | |
154 | ||
155 | /* C array declarators are ordered inside out so prepend them. Also by | |
156 | convention qualifiers of base types precede the type specifier (e.g. | |
157 | const int vs. int const) even though the two forms are equivalent. */ | |
158 | ||
159 | if (kind == CTF_K_ARRAY || (is_qual && prec == CTF_PREC_BASE)) | |
160 | ctf_list_prepend (&cd->cd_nodes[prec], cdp); | |
161 | else | |
162 | ctf_list_append (&cd->cd_nodes[prec], cdp); | |
163 | } | |
164 | ||
165 | _libctf_printflike_ (2, 3) | |
166 | void ctf_decl_sprintf (ctf_decl_t *cd, const char *format, ...) | |
167 | { | |
168 | va_list ap; | |
169 | char *str; | |
170 | int n; | |
171 | ||
172 | if (cd->cd_enomem) | |
173 | return; | |
174 | ||
175 | va_start (ap, format); | |
176 | n = vasprintf (&str, format, ap); | |
177 | va_end (ap); | |
178 | ||
179 | if (n > 0) | |
de07e349 NA |
180 | { |
181 | char *newbuf; | |
182 | if ((newbuf = ctf_str_append (cd->cd_buf, str)) != NULL) | |
183 | cd->cd_buf = newbuf; | |
184 | } | |
316afdb1 NA |
185 | |
186 | /* Sticky error condition. */ | |
de07e349 | 187 | if (n < 0 || cd->cd_buf == NULL) |
316afdb1 NA |
188 | { |
189 | free (cd->cd_buf); | |
190 | cd->cd_buf = NULL; | |
191 | cd->cd_enomem = 1; | |
192 | } | |
193 | ||
194 | free (str); | |
195 | } | |
196 | ||
197 | char *ctf_decl_buf (ctf_decl_t *cd) | |
198 | { | |
b255b35f NA |
199 | char *buf = cd->cd_buf; |
200 | cd->cd_buf = NULL; | |
201 | return buf; | |
316afdb1 | 202 | } |