1 /* Some code common to C and ObjC front ends.
2 Copyright (C) 2001-2021 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC 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 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "c-tree.h"
24 #include "intl.h"
25 #include "c-family/c-pretty-print.h"
26 #include "tree-pretty-print.h"
27 #include "gimple-pretty-print.h"
28 #include "langhooks.h"
29 #include "c-objc-common.h"
30 #include "gcc-rich-location.h"
31 #include "stringpool.h"
32 #include "attribs.h"
33
34 static bool c_tree_printer (pretty_printer *, text_info *, const char *,
35 int, bool, bool, bool, bool *, const char **);
36
37 bool
c_missing_noreturn_ok_p(tree decl)38 c_missing_noreturn_ok_p (tree decl)
39 {
40 /* A missing noreturn is not ok for freestanding implementations and
41 ok for the `main' function in hosted implementations. */
42 return flag_hosted && MAIN_NAME_P (DECL_ASSEMBLER_NAME (decl));
43 }
44
45 /* Called from check_global_declaration. */
46
47 bool
c_warn_unused_global_decl(const_tree decl)48 c_warn_unused_global_decl (const_tree decl)
49 {
50 if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
51 return false;
52 if (DECL_IN_SYSTEM_HEADER (decl))
53 return false;
54
55 return true;
56 }
57
58 /* Initialization common to C and Objective-C front ends. */
59 bool
c_objc_common_init(void)60 c_objc_common_init (void)
61 {
62 c_init_decl_processing ();
63
64 return c_common_init ();
65 }
66
67 /* Decide whether it's worth saying that TYPE is also known as some other
68 type. Return the other type if so, otherwise return TYPE. */
69
70 static tree
get_aka_type(tree type)71 get_aka_type (tree type)
72 {
73 if (type == error_mark_node)
74 return type;
75
76 tree result;
77 if (typedef_variant_p (type))
78 {
79 /* Saying that "foo" is also known as "struct foo" or
80 "struct <anonymous>" is unlikely to be useful, since users of
81 structure-like types would already know that they're structures.
82 The same applies to unions and enums; in general, printing the
83 tag is only useful if it has a different name. */
84 tree orig_type = DECL_ORIGINAL_TYPE (TYPE_NAME (type));
85 tree_code code = TREE_CODE (orig_type);
86 tree orig_id = TYPE_IDENTIFIER (orig_type);
87 if ((code == RECORD_TYPE || code == UNION_TYPE || code == ENUMERAL_TYPE)
88 && (!orig_id || TYPE_IDENTIFIER (type) == orig_id))
89 return type;
90
91 if (!user_facing_original_type_p (type))
92 return type;
93
94 result = get_aka_type (orig_type);
95 }
96 else
97 {
98 tree canonical = TYPE_CANONICAL (type);
99 if (canonical && TREE_CODE (type) != TREE_CODE (canonical))
100 return canonical;
101
102 /* Recursive calls might choose a middle ground between TYPE
103 (which has no typedefs stripped) and CANONICAL (which has
104 all typedefs stripped). So try to reuse TYPE or CANONICAL if
105 convenient, but be prepared to create a new type if necessary. */
106 switch (TREE_CODE (type))
107 {
108 case POINTER_TYPE:
109 case REFERENCE_TYPE:
110 {
111 tree target_type = get_aka_type (TREE_TYPE (type));
112
113 if (target_type == TREE_TYPE (type))
114 return type;
115
116 if (canonical && target_type == TREE_TYPE (canonical))
117 return canonical;
118
119 result = (TREE_CODE (type) == POINTER_TYPE
120 ? build_pointer_type (target_type)
121 : build_reference_type (target_type));
122 break;
123 }
124
125 case ARRAY_TYPE:
126 {
127 tree element_type = get_aka_type (TREE_TYPE (type));
128 tree index_type = (TYPE_DOMAIN (type)
129 ? get_aka_type (TYPE_DOMAIN (type))
130 : NULL_TREE);
131
132 if (element_type == TREE_TYPE (type)
133 && index_type == TYPE_DOMAIN (type))
134 return type;
135
136 if (canonical
137 && element_type == TREE_TYPE (canonical)
138 && index_type == TYPE_DOMAIN (canonical))
139 return canonical;
140
141 result = build_array_type (element_type, index_type,
142 TYPE_TYPELESS_STORAGE (type));
143 break;
144 }
145
146 case FUNCTION_TYPE:
147 {
148 tree return_type = get_aka_type (TREE_TYPE (type));
149
150 tree args = TYPE_ARG_TYPES (type);
151 if (args == error_mark_node)
152 return type;
153
154 auto_vec<tree, 32> arg_types;
155 bool type_ok_p = true;
156 while (args && args != void_list_node)
157 {
158 tree arg_type = get_aka_type (TREE_VALUE (args));
159 arg_types.safe_push (arg_type);
160 type_ok_p &= (arg_type == TREE_VALUE (args));
161 args = TREE_CHAIN (args);
162 }
163
164 if (type_ok_p && return_type == TREE_TYPE (type))
165 return type;
166
167 unsigned int i;
168 tree arg_type;
169 FOR_EACH_VEC_ELT_REVERSE (arg_types, i, arg_type)
170 args = tree_cons (NULL_TREE, arg_type, args);
171 result = build_function_type (return_type, args);
172 break;
173 }
174
175 default:
176 return canonical ? canonical : type;
177 }
178 }
179 return build_type_attribute_qual_variant (result, TYPE_ATTRIBUTES (type),
180 TYPE_QUALS (type));
181 }
182
183 /* Print T to CPP. */
184
185 static void
print_type(c_pretty_printer * cpp,tree t,bool * quoted)186 print_type (c_pretty_printer *cpp, tree t, bool *quoted)
187 {
188 if (t == error_mark_node)
189 {
190 pp_string (cpp, _("{erroneous}"));
191 return;
192 }
193
194 gcc_assert (TYPE_P (t));
195 struct obstack *ob = pp_buffer (cpp)->obstack;
196 char *p = (char *) obstack_base (ob);
197 /* Remember the end of the initial dump. */
198 int len = obstack_object_size (ob);
199
200 tree name = TYPE_NAME (t);
201 if (name && TREE_CODE (name) == TYPE_DECL && DECL_NAME (name))
202 pp_identifier (cpp, lang_hooks.decl_printable_name (name, 2));
203 else
204 cpp->type_id (t);
205
206 /* If we're printing a type that involves typedefs, also print the
207 stripped version. But sometimes the stripped version looks
208 exactly the same, so we don't want it after all. To avoid
209 printing it in that case, we play ugly obstack games. */
210 tree aka_type = get_aka_type (t);
211 if (aka_type != t)
212 {
213 c_pretty_printer cpp2;
214 /* Print the stripped version into a temporary printer. */
215 cpp2.type_id (aka_type);
216 struct obstack *ob2 = cpp2.buffer->obstack;
217 /* Get the stripped version from the temporary printer. */
218 const char *aka = (char *) obstack_base (ob2);
219 int aka_len = obstack_object_size (ob2);
220 int type1_len = obstack_object_size (ob) - len;
221
222 /* If they are identical, bail out. */
223 if (aka_len == type1_len && memcmp (p + len, aka, aka_len) == 0)
224 return;
225
226 /* They're not, print the stripped version now. */
227 if (*quoted)
228 pp_end_quote (cpp, pp_show_color (cpp));
229 pp_c_whitespace (cpp);
230 pp_left_brace (cpp);
231 pp_c_ws_string (cpp, _("aka"));
232 pp_c_whitespace (cpp);
233 if (*quoted)
234 pp_begin_quote (cpp, pp_show_color (cpp));
235 cpp->type_id (aka_type);
236 if (*quoted)
237 pp_end_quote (cpp, pp_show_color (cpp));
238 pp_right_brace (cpp);
239 /* No further closing quotes are needed. */
240 *quoted = false;
241 }
242 }
243
244 /* Called during diagnostic message formatting process to print a
245 source-level entity onto BUFFER. The meaning of the format specifiers
246 is as follows:
247 %D: a general decl,
248 %E: an identifier or expression,
249 %F: a function declaration,
250 %T: a type.
251 %V: a list of type qualifiers from a tree.
252 %v: an explicit list of type qualifiers
253 %#v: an explicit list of type qualifiers of a function type.
254
255 Please notice when called, the `%' part was already skipped by the
256 diagnostic machinery. */
257 static bool
c_tree_printer(pretty_printer * pp,text_info * text,const char * spec,int precision,bool wide,bool set_locus,bool hash,bool * quoted,const char **)258 c_tree_printer (pretty_printer *pp, text_info *text, const char *spec,
259 int precision, bool wide, bool set_locus, bool hash,
260 bool *quoted, const char **)
261 {
262 tree t = NULL_TREE;
263 // FIXME: the next cast should be a dynamic_cast, when it is permitted.
264 c_pretty_printer *cpp = (c_pretty_printer *) pp;
265 pp->padding = pp_none;
266
267 if (precision != 0 || wide)
268 return false;
269
270 if (*spec != 'v')
271 {
272 t = va_arg (*text->args_ptr, tree);
273 if (set_locus)
274 text->set_location (0, DECL_SOURCE_LOCATION (t),
275 SHOW_RANGE_WITH_CARET);
276 }
277
278 switch (*spec)
279 {
280 case 'D':
281 if (VAR_P (t) && DECL_HAS_DEBUG_EXPR_P (t))
282 {
283 t = DECL_DEBUG_EXPR (t);
284 if (!DECL_P (t))
285 {
286 cpp->expression (t);
287 return true;
288 }
289 }
290 /* FALLTHRU */
291
292 case 'F':
293 if (DECL_NAME (t))
294 {
295 pp_identifier (cpp, lang_hooks.decl_printable_name (t, 2));
296 return true;
297 }
298 break;
299
300 case 'T':
301 print_type (cpp, t, quoted);
302 return true;
303
304 case 'E':
305 if (TREE_CODE (t) == IDENTIFIER_NODE)
306 pp_identifier (cpp, IDENTIFIER_POINTER (t));
307 else
308 cpp->expression (t);
309 return true;
310
311 case 'V':
312 pp_c_type_qualifier_list (cpp, t);
313 return true;
314
315 case 'v':
316 pp_c_cv_qualifiers (cpp, va_arg (*text->args_ptr, int), hash);
317 return true;
318
319 default:
320 return false;
321 }
322
323 pp_string (cpp, _("({anonymous})"));
324 return true;
325 }
326
327 /* C-specific implementation of range_label::get_text () vfunc for
328 range_label_for_type_mismatch. */
329
330 label_text
get_text(unsigned)331 range_label_for_type_mismatch::get_text (unsigned /*range_idx*/) const
332 {
333 if (m_labelled_type == NULL_TREE)
334 return label_text::borrow (NULL);
335
336 c_pretty_printer cpp;
337 bool quoted = false;
338 print_type (&cpp, m_labelled_type, "ed);
339 return label_text::take (xstrdup (pp_formatted_text (&cpp)));
340 }
341
342
343 /* In C and ObjC, all decls have "C" linkage. */
344 bool
has_c_linkage(const_tree decl ATTRIBUTE_UNUSED)345 has_c_linkage (const_tree decl ATTRIBUTE_UNUSED)
346 {
347 return true;
348 }
349
350 void
c_initialize_diagnostics(diagnostic_context * context)351 c_initialize_diagnostics (diagnostic_context *context)
352 {
353 pretty_printer *base = context->printer;
354 c_pretty_printer *pp = XNEW (c_pretty_printer);
355 context->printer = new (pp) c_pretty_printer ();
356
357 /* It is safe to free this object because it was previously XNEW()'d. */
358 base->~pretty_printer ();
359 XDELETE (base);
360
361 c_common_diagnostics_set_defaults (context);
362 diagnostic_format_decoder (context) = &c_tree_printer;
363 }
364
365 int
c_types_compatible_p(tree x,tree y)366 c_types_compatible_p (tree x, tree y)
367 {
368 return comptypes (TYPE_MAIN_VARIANT (x), TYPE_MAIN_VARIANT (y));
369 }
370
371 /* Determine if the type is a vla type for the backend. */
372
373 bool
c_vla_unspec_p(tree x,tree fn ATTRIBUTE_UNUSED)374 c_vla_unspec_p (tree x, tree fn ATTRIBUTE_UNUSED)
375 {
376 return c_vla_type_p (x);
377 }
378
379 /* Special routine to get the alias set of T for C. */
380
381 alias_set_type
c_get_alias_set(tree t)382 c_get_alias_set (tree t)
383 {
384 /* Allow aliasing between enumeral types and the underlying
385 integer type. This is required since those are compatible types. */
386 if (TREE_CODE (t) == ENUMERAL_TYPE)
387 {
388 tree t1 = c_common_type_for_size (tree_to_uhwi (TYPE_SIZE (t)),
389 /* short-cut commoning to signed
390 type. */
391 false);
392 return get_alias_set (t1);
393 }
394
395 return c_common_get_alias_set (t);
396 }
397