xref: /freebsd/cddl/contrib/opensolaris/common/ctf/ctf_decl.c (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * CTF Declaration Stack
31  *
32  * In order to implement ctf_type_name(), we must convert a type graph back
33  * into a C type declaration.  Unfortunately, a type graph represents a storage
34  * class ordering of the type whereas a type declaration must obey the C rules
35  * for operator precedence, and the two orderings are frequently in conflict.
36  * For example, consider these CTF type graphs and their C declarations:
37  *
38  * CTF_K_POINTER -> CTF_K_FUNCTION -> CTF_K_INTEGER  : int (*)()
39  * CTF_K_POINTER -> CTF_K_ARRAY -> CTF_K_INTEGER     : int (*)[]
40  *
41  * In each case, parentheses are used to raise operator * to higher lexical
42  * precedence, so the string form of the C declaration cannot be constructed by
43  * walking the type graph links and forming the string from left to right.
44  *
45  * The functions in this file build a set of stacks from the type graph nodes
46  * corresponding to the C operator precedence levels in the appropriate order.
47  * The code in ctf_type_name() can then iterate over the levels and nodes in
48  * lexical precedence order and construct the final C declaration string.
49  */
50 
51 #include <ctf_impl.h>
52 
53 void
54 ctf_decl_init(ctf_decl_t *cd, char *buf, size_t len)
55 {
56 	int i;
57 
58 	bzero(cd, sizeof (ctf_decl_t));
59 
60 	for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++)
61 		cd->cd_order[i] = CTF_PREC_BASE - 1;
62 
63 	cd->cd_qualp = CTF_PREC_BASE;
64 	cd->cd_ordp = CTF_PREC_BASE;
65 
66 	cd->cd_buf = buf;
67 	cd->cd_ptr = buf;
68 	cd->cd_end = buf + len;
69 }
70 
71 void
72 ctf_decl_fini(ctf_decl_t *cd)
73 {
74 	ctf_decl_node_t *cdp, *ndp;
75 	int i;
76 
77 	for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++) {
78 		for (cdp = ctf_list_next(&cd->cd_nodes[i]);
79 		    cdp != NULL; cdp = ndp) {
80 			ndp = ctf_list_next(cdp);
81 			ctf_free(cdp, sizeof (ctf_decl_node_t));
82 		}
83 	}
84 }
85 
86 void
87 ctf_decl_push(ctf_decl_t *cd, ctf_file_t *fp, ctf_id_t type)
88 {
89 	ctf_decl_node_t *cdp;
90 	ctf_decl_prec_t prec;
91 	uint_t ctype, kind, n = 1;
92 	int is_qual = 0;
93 
94 	const void *tp;
95 	ctf_arinfo_t ar;
96 
97 	if ((tp = ctf_lookup_by_id(&fp, type)) == NULL) {
98 		cd->cd_err = fp->ctf_errno;
99 		return;
100 	}
101 
102 	ctf_get_ctt_info(fp, tp, &kind, NULL, NULL);
103 	ctf_get_ctt_index(fp, tp, NULL, &ctype, NULL);
104 
105 	switch (kind) {
106 	case CTF_K_ARRAY:
107 		(void) ctf_array_info(fp, type, &ar);
108 		ctf_decl_push(cd, fp, ar.ctr_contents);
109 		n = ar.ctr_nelems;
110 		prec = CTF_PREC_ARRAY;
111 		break;
112 
113 	case CTF_K_TYPEDEF:
114 		if (ctf_type_rname(fp, tp)[0] == '\0') {
115 			ctf_decl_push(cd, fp, ctype);
116 			return;
117 		}
118 		prec = CTF_PREC_BASE;
119 		break;
120 
121 	case CTF_K_FUNCTION:
122 		ctf_decl_push(cd, fp, ctype);
123 		prec = CTF_PREC_FUNCTION;
124 		break;
125 
126 	case CTF_K_POINTER:
127 		ctf_decl_push(cd, fp, ctype);
128 		prec = CTF_PREC_POINTER;
129 		break;
130 
131 	case CTF_K_VOLATILE:
132 	case CTF_K_CONST:
133 	case CTF_K_RESTRICT:
134 		ctf_decl_push(cd, fp, ctype);
135 		prec = cd->cd_qualp;
136 		is_qual++;
137 		break;
138 
139 	default:
140 		prec = CTF_PREC_BASE;
141 	}
142 
143 	if ((cdp = ctf_alloc(sizeof (ctf_decl_node_t))) == NULL) {
144 		cd->cd_err = EAGAIN;
145 		return;
146 	}
147 
148 	cdp->cd_type = type;
149 	cdp->cd_kind = kind;
150 	cdp->cd_n = n;
151 
152 	if (ctf_list_next(&cd->cd_nodes[prec]) == NULL)
153 		cd->cd_order[prec] = cd->cd_ordp++;
154 
155 	/*
156 	 * Reset cd_qualp to the highest precedence level that we've seen so
157 	 * far that can be qualified (CTF_PREC_BASE or CTF_PREC_POINTER).
158 	 */
159 	if (prec > cd->cd_qualp && prec < CTF_PREC_ARRAY)
160 		cd->cd_qualp = prec;
161 
162 	/*
163 	 * C array declarators are ordered inside out so prepend them.  Also by
164 	 * convention qualifiers of base types precede the type specifier (e.g.
165 	 * const int vs. int const) even though the two forms are equivalent.
166 	 */
167 	if (kind == CTF_K_ARRAY || (is_qual && prec == CTF_PREC_BASE))
168 		ctf_list_prepend(&cd->cd_nodes[prec], cdp);
169 	else
170 		ctf_list_append(&cd->cd_nodes[prec], cdp);
171 }
172 
173 /*PRINTFLIKE2*/
174 void
175 ctf_decl_sprintf(ctf_decl_t *cd, const char *format, ...)
176 {
177 	size_t len = (size_t)(cd->cd_end - cd->cd_ptr);
178 	va_list ap;
179 	size_t n;
180 
181 	va_start(ap, format);
182 	n = vsnprintf(cd->cd_ptr, len, format, ap);
183 	va_end(ap);
184 
185 	cd->cd_ptr += MIN(n, len);
186 	cd->cd_len += n;
187 }
188