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471086d6 | 1 | /* Language-level data type conversion for GNU C++. |
107c7f39 | 2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, |
3 | 1999, 2000 Free Software Foundation, Inc. | |
471086d6 | 4 | Hacked by Michael Tiemann (tiemann@cygnus.com) |
5 | ||
6 | This file is part of GNU CC. | |
7 | ||
8 | GNU CC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2, or (at your option) | |
11 | any later version. | |
12 | ||
13 | GNU CC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GNU CC; see the file COPYING. If not, write to | |
c58d4270 | 20 | the Free Software Foundation, 59 Temple Place - Suite 330, |
21 | Boston, MA 02111-1307, USA. */ | |
471086d6 | 22 | |
23 | ||
24 | /* This file contains the functions for converting C expressions | |
25 | to different data types. The only entry point is `convert'. | |
26 | Every language front end must have a `convert' function | |
27 | but what kind of conversions it does will depend on the language. */ | |
28 | ||
29 | #include "config.h" | |
b3ef7553 | 30 | #include "system.h" |
471086d6 | 31 | #include "tree.h" |
32 | #include "flags.h" | |
33 | #include "cp-tree.h" | |
471086d6 | 34 | #include "convert.h" |
f0eaeecd | 35 | #include "toplev.h" |
2e8226f7 | 36 | #include "decl.h" |
96624a9e | 37 | |
045ed8f8 | 38 | static tree cp_convert_to_pointer PARAMS ((tree, tree, int)); |
24054144 | 39 | static tree convert_to_pointer_force PARAMS ((tree, tree)); |
ca106ab1 | 40 | static tree build_up_reference PARAMS ((tree, tree, int, tree)); |
519ba62c | 41 | static void warn_ref_binding PARAMS ((tree, tree, tree)); |
71ccdfff | 42 | |
471086d6 | 43 | /* Change of width--truncation and extension of integers or reals-- |
44 | is represented with NOP_EXPR. Proper functioning of many things | |
45 | assumes that no other conversions can be NOP_EXPRs. | |
46 | ||
47 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
48 | Converting integer to real uses FLOAT_EXPR | |
49 | and real to integer uses FIX_TRUNC_EXPR. | |
50 | ||
51 | Here is a list of all the functions that assume that widening and | |
52 | narrowing is always done with a NOP_EXPR: | |
53 | In convert.c, convert_to_integer. | |
54 | In c-typeck.c, build_binary_op_nodefault (boolean ops), | |
55 | and truthvalue_conversion. | |
56 | In expr.c: expand_expr, for operands of a MULT_EXPR. | |
57 | In fold-const.c: fold. | |
58 | In tree.c: get_narrower and get_unwidened. | |
59 | ||
60 | C++: in multiple-inheritance, converting between pointers may involve | |
61 | adjusting them by a delta stored within the class definition. */ | |
62 | \f | |
63 | /* Subroutines of `convert'. */ | |
64 | ||
471086d6 | 65 | /* if converting pointer to pointer |
66 | if dealing with classes, check for derived->base or vice versa | |
67 | else if dealing with method pointers, delegate | |
68 | else convert blindly | |
69 | else if converting class, pass off to build_type_conversion | |
045ed8f8 | 70 | else try C-style pointer conversion. If FORCE is true then allow |
71 | conversions via virtual bases (these are permitted by reinterpret_cast, | |
72 | but not static_cast). */ | |
96624a9e | 73 | |
471086d6 | 74 | static tree |
045ed8f8 | 75 | cp_convert_to_pointer (type, expr, force) |
471086d6 | 76 | tree type, expr; |
045ed8f8 | 77 | int force; |
471086d6 | 78 | { |
79 | register tree intype = TREE_TYPE (expr); | |
74002e1d | 80 | register enum tree_code form; |
f82eeb87 | 81 | tree rval; |
74002e1d | 82 | |
96624a9e | 83 | if (IS_AGGR_TYPE (intype)) |
84 | { | |
96624a9e | 85 | intype = complete_type (intype); |
4b72716d | 86 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 87 | { |
905d4035 | 88 | cp_error ("can't convert from incomplete type `%T' to `%T'", |
96624a9e | 89 | intype, type); |
90 | return error_mark_node; | |
91 | } | |
92 | ||
1c16607c | 93 | rval = build_type_conversion (type, expr, 1); |
96624a9e | 94 | if (rval) |
95 | { | |
96 | if (rval == error_mark_node) | |
905d4035 | 97 | cp_error ("conversion of `%E' from `%T' to `%T' is ambiguous", |
96624a9e | 98 | expr, intype, type); |
99 | return rval; | |
100 | } | |
101 | } | |
102 | ||
860740a7 | 103 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 104 | if (TREE_CODE (type) == POINTER_TYPE |
105 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
e3cfe3ce | 106 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 107 | { |
108 | /* Allow an implicit this pointer for pointer to member | |
109 | functions. */ | |
860740a7 | 110 | if (TYPE_PTRMEMFUNC_P (intype)) |
38281c46 | 111 | { |
860740a7 | 112 | tree fntype = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (intype)); |
2917b86f | 113 | tree decl = maybe_dummy_object (TYPE_METHOD_BASETYPE (fntype), 0); |
38281c46 | 114 | expr = build (OFFSET_REF, fntype, decl, expr); |
115 | } | |
116 | ||
117 | if (TREE_CODE (expr) == OFFSET_REF | |
118 | && TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
119 | expr = resolve_offset_ref (expr); | |
120 | if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
121 | expr = build_addr_func (expr); | |
122 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) | |
123 | { | |
124 | if (TREE_CODE (TREE_TYPE (TREE_TYPE (expr))) == METHOD_TYPE) | |
125 | if (pedantic || warn_pmf2ptr) | |
905d4035 | 126 | cp_pedwarn ("converting from `%T' to `%T'", TREE_TYPE (expr), |
38281c46 | 127 | type); |
128 | return build1 (NOP_EXPR, type, expr); | |
129 | } | |
130 | intype = TREE_TYPE (expr); | |
131 | } | |
132 | ||
74002e1d | 133 | form = TREE_CODE (intype); |
134 | ||
2b77484d | 135 | if (POINTER_TYPE_P (intype)) |
471086d6 | 136 | { |
137 | intype = TYPE_MAIN_VARIANT (intype); | |
138 | ||
139 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 140 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 141 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
bccffb3a | 142 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
143 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
2edf445e | 144 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE |
145 | /* If EXPR is NULL, then we don't need to do any arithmetic | |
146 | to convert it: | |
147 | ||
148 | [conv.ptr] | |
149 | ||
150 | The null pointer value is converted to the null pointer | |
151 | value of the destination type. */ | |
152 | && !integer_zerop (expr)) | |
471086d6 | 153 | { |
154 | enum tree_code code = PLUS_EXPR; | |
155 | tree binfo = get_binfo (TREE_TYPE (type), TREE_TYPE (intype), 1); | |
156 | if (binfo == error_mark_node) | |
157 | return error_mark_node; | |
158 | if (binfo == NULL_TREE) | |
159 | { | |
160 | binfo = get_binfo (TREE_TYPE (intype), TREE_TYPE (type), 1); | |
161 | if (binfo == error_mark_node) | |
162 | return error_mark_node; | |
163 | code = MINUS_EXPR; | |
164 | } | |
165 | if (binfo) | |
166 | { | |
167 | if (TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (type)) | |
168 | || TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (intype)) | |
169 | || ! BINFO_OFFSET_ZEROP (binfo)) | |
170 | { | |
171 | /* Need to get the path we took. */ | |
172 | tree path; | |
173 | ||
174 | if (code == PLUS_EXPR) | |
985e9ee0 | 175 | get_base_distance (TREE_TYPE (type), TREE_TYPE (intype), |
176 | 0, &path); | |
471086d6 | 177 | else |
985e9ee0 | 178 | get_base_distance (TREE_TYPE (intype), TREE_TYPE (type), |
179 | 0, &path); | |
471086d6 | 180 | return build_vbase_path (code, type, expr, path, 0); |
181 | } | |
182 | } | |
183 | } | |
471086d6 | 184 | |
1c16607c | 185 | if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) |
bea7d742 | 186 | { |
a17aefa2 | 187 | tree b1; |
188 | tree b2; | |
189 | tree binfo; | |
045ed8f8 | 190 | tree virt_binfo; |
a17aefa2 | 191 | enum tree_code code; |
192 | ||
193 | b1 = TYPE_OFFSET_BASETYPE (TREE_TYPE (type)); | |
194 | b2 = TYPE_OFFSET_BASETYPE (TREE_TYPE (intype)); | |
195 | binfo = get_binfo (b2, b1, 1); | |
fc9fc8d8 | 196 | |
bea7d742 | 197 | if (binfo == NULL_TREE) |
fc9fc8d8 | 198 | { |
199 | binfo = get_binfo (b1, b2, 1); | |
200 | code = MINUS_EXPR; | |
201 | } | |
a17aefa2 | 202 | else |
203 | code = PLUS_EXPR; | |
fc9fc8d8 | 204 | |
bea7d742 | 205 | if (binfo == error_mark_node) |
206 | return error_mark_node; | |
a17aefa2 | 207 | |
045ed8f8 | 208 | virt_binfo = binfo_from_vbase (binfo); |
209 | if (virt_binfo) | |
7045d67a | 210 | { |
045ed8f8 | 211 | if (force) |
1bbb5947 | 212 | cp_warning ("pointer to member cast via virtual base `%T' of `%T'", |
045ed8f8 | 213 | BINFO_TYPE (virt_binfo), |
1bbb5947 | 214 | BINFO_TYPE (BINFO_INHERITANCE_CHAIN (virt_binfo))); |
045ed8f8 | 215 | else |
216 | { | |
217 | cp_error ("pointer to member cast via virtual base `%T' of `%T'", | |
218 | BINFO_TYPE (virt_binfo), | |
219 | BINFO_TYPE (BINFO_INHERITANCE_CHAIN (virt_binfo))); | |
220 | return error_mark_node; | |
221 | } | |
1bbb5947 | 222 | /* This is a reinterpret cast, whose result is unspecified. |
223 | We choose to do nothing. */ | |
224 | return build1 (NOP_EXPR, type, expr); | |
7045d67a | 225 | } |
226 | ||
a17aefa2 | 227 | if (TREE_CODE (expr) == PTRMEM_CST) |
228 | expr = cplus_expand_constant (expr); | |
229 | ||
1bbb5947 | 230 | if (binfo) |
231 | expr = size_binop (code, convert (sizetype, expr), | |
902de8ed | 232 | BINFO_OFFSET (binfo)); |
bea7d742 | 233 | } |
2b77484d | 234 | else if (TYPE_PTRMEMFUNC_P (type)) |
ce28ee2e | 235 | { |
905d4035 | 236 | cp_error ("cannot convert `%E' from type `%T' to type `%T'", |
ce28ee2e | 237 | expr, intype, type); |
238 | return error_mark_node; | |
239 | } | |
240 | ||
f82eeb87 | 241 | rval = build1 (NOP_EXPR, type, expr); |
242 | TREE_CONSTANT (rval) = TREE_CONSTANT (expr); | |
243 | return rval; | |
471086d6 | 244 | } |
2b77484d | 245 | else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)) |
7045d67a | 246 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
2b77484d | 247 | else if (TYPE_PTRMEMFUNC_P (intype)) |
248 | { | |
249 | cp_error ("cannot convert `%E' from type `%T' to type `%T'", | |
250 | expr, intype, type); | |
251 | return error_mark_node; | |
252 | } | |
471086d6 | 253 | |
254 | my_friendly_assert (form != OFFSET_TYPE, 186); | |
255 | ||
471086d6 | 256 | if (integer_zerop (expr)) |
257 | { | |
2b77484d | 258 | if (TYPE_PTRMEMFUNC_P (type)) |
f05d5d03 | 259 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
ad63a0fc | 260 | |
606b494c | 261 | if (TYPE_PTRMEM_P (type)) |
5ad590ad | 262 | /* A NULL pointer-to-member is represented by -1, not by |
263 | zero. */ | |
ad63a0fc | 264 | expr = build_int_2 (-1, -1); |
265 | else | |
266 | expr = build_int_2 (0, 0); | |
471086d6 | 267 | TREE_TYPE (expr) = type; |
268 | return expr; | |
269 | } | |
270 | ||
bb0726a1 | 271 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 272 | { |
c5aa1e92 | 273 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 274 | return build1 (CONVERT_EXPR, type, expr); |
c4a8ac95 | 275 | expr = cp_convert (type_for_size (POINTER_SIZE, 0), expr); |
471086d6 | 276 | /* Modes may be different but sizes should be the same. */ |
277 | if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
278 | != GET_MODE_SIZE (TYPE_MODE (type))) | |
279 | /* There is supposed to be some integral type | |
280 | that is the same width as a pointer. */ | |
281 | abort (); | |
282 | return convert_to_pointer (type, expr); | |
283 | } | |
284 | ||
cc4d0855 | 285 | if (type_unknown_p (expr)) |
83278475 | 286 | return instantiate_type (type, expr, itf_complain); |
cc4d0855 | 287 | |
905d4035 | 288 | cp_error ("cannot convert `%E' from type `%T' to type `%T'", |
471086d6 | 289 | expr, intype, type); |
290 | return error_mark_node; | |
291 | } | |
292 | ||
293 | /* Like convert, except permit conversions to take place which | |
294 | are not normally allowed due to access restrictions | |
295 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 296 | |
471086d6 | 297 | static tree |
298 | convert_to_pointer_force (type, expr) | |
299 | tree type, expr; | |
300 | { | |
301 | register tree intype = TREE_TYPE (expr); | |
302 | register enum tree_code form = TREE_CODE (intype); | |
303 | ||
304 | if (integer_zerop (expr)) | |
305 | { | |
471086d6 | 306 | expr = build_int_2 (0, 0); |
307 | TREE_TYPE (expr) = type; | |
308 | return expr; | |
309 | } | |
310 | ||
471086d6 | 311 | if (form == POINTER_TYPE) |
312 | { | |
313 | intype = TYPE_MAIN_VARIANT (intype); | |
314 | ||
315 | if (TYPE_MAIN_VARIANT (type) != intype | |
316 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
bccffb3a | 317 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
318 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
471086d6 | 319 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
320 | { | |
321 | enum tree_code code = PLUS_EXPR; | |
322 | tree path; | |
323 | int distance = get_base_distance (TREE_TYPE (type), | |
324 | TREE_TYPE (intype), 0, &path); | |
325 | if (distance == -2) | |
326 | { | |
9a98d025 | 327 | cp_error ("type `%T' is ambiguous base of `%T'", |
b0df6589 | 328 | TREE_TYPE (type), |
9a98d025 | 329 | TREE_TYPE (intype)); |
471086d6 | 330 | return error_mark_node; |
331 | } | |
332 | if (distance == -1) | |
333 | { | |
334 | distance = get_base_distance (TREE_TYPE (intype), | |
335 | TREE_TYPE (type), 0, &path); | |
336 | if (distance == -2) | |
9a98d025 | 337 | { |
338 | cp_error ("type `%T' is ambiguous base of `%T'", | |
339 | TREE_TYPE (intype), | |
340 | TREE_TYPE (type)); | |
341 | return error_mark_node; | |
342 | } | |
471086d6 | 343 | if (distance < 0) |
344 | /* Doesn't need any special help from us. */ | |
345 | return build1 (NOP_EXPR, type, expr); | |
346 | ||
347 | code = MINUS_EXPR; | |
348 | } | |
349 | return build_vbase_path (code, type, expr, path, 0); | |
350 | } | |
471086d6 | 351 | } |
352 | ||
045ed8f8 | 353 | return cp_convert_to_pointer (type, expr, 1); |
471086d6 | 354 | } |
355 | ||
356 | /* We are passing something to a function which requires a reference. | |
357 | The type we are interested in is in TYPE. The initial | |
358 | value we have to begin with is in ARG. | |
359 | ||
360 | FLAGS controls how we manage access checking. | |
ca106ab1 | 361 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
362 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 363 | |
471086d6 | 364 | static tree |
ca106ab1 | 365 | build_up_reference (type, arg, flags, decl) |
366 | tree type, arg, decl; | |
6a44e72e | 367 | int flags; |
471086d6 | 368 | { |
c76251c1 | 369 | tree rval; |
0543e7a9 | 370 | tree argtype = TREE_TYPE (arg); |
471086d6 | 371 | tree target_type = TREE_TYPE (type); |
c23ebfdd | 372 | tree stmt_expr = NULL_TREE; |
471086d6 | 373 | |
374 | my_friendly_assert (TREE_CODE (type) == REFERENCE_TYPE, 187); | |
471086d6 | 375 | |
c76251c1 | 376 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 377 | { |
ca106ab1 | 378 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
379 | here because it needs to live as long as DECL. */ | |
c76251c1 | 380 | tree targ = arg; |
ca106ab1 | 381 | |
382 | arg = build_decl (VAR_DECL, NULL_TREE, argtype); | |
383 | DECL_ARTIFICIAL (arg) = 1; | |
384 | TREE_USED (arg) = 1; | |
385 | TREE_STATIC (arg) = TREE_STATIC (decl); | |
386 | ||
387 | if (TREE_STATIC (decl)) | |
388 | { | |
389 | /* Namespace-scope or local static; give it a mangled name. */ | |
390 | tree name = mangle_ref_init_variable (decl); | |
391 | DECL_NAME (arg) = name; | |
392 | SET_DECL_ASSEMBLER_NAME (arg, name); | |
393 | arg = pushdecl_top_level (arg); | |
394 | } | |
471086d6 | 395 | else |
396 | { | |
243adba6 | 397 | /* Automatic; make sure we handle the cleanup properly. */ |
614cc70d | 398 | maybe_push_cleanup_level (argtype); |
ca106ab1 | 399 | arg = pushdecl (arg); |
1ad432f2 | 400 | } |
c23ebfdd | 401 | |
402 | /* Process the initializer for the declaration. */ | |
38281c46 | 403 | DECL_INITIAL (arg) = targ; |
ce23987e | 404 | cp_finish_decl (arg, targ, NULL_TREE, |
011310f7 | 405 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 406 | } |
c76251c1 | 407 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
1d8e4310 | 408 | return get_target_expr (arg); |
1ad432f2 | 409 | |
ca106ab1 | 410 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 411 | address, transform all occurrences of the register, into a memory |
412 | reference we could win better. */ | |
c76251c1 | 413 | rval = build_unary_op (ADDR_EXPR, arg, 1); |
15e55420 | 414 | if (rval == error_mark_node) |
415 | return error_mark_node; | |
416 | ||
6686e84d | 417 | if ((flags & LOOKUP_PROTECT) |
418 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
419 | && IS_AGGR_TYPE (argtype) | |
420 | && IS_AGGR_TYPE (target_type)) | |
421 | { | |
422 | /* We go through get_binfo for the access control. */ | |
423 | tree binfo = get_binfo (target_type, argtype, 1); | |
424 | if (binfo == error_mark_node) | |
425 | return error_mark_node; | |
426 | if (binfo == NULL_TREE) | |
427 | return error_not_base_type (target_type, argtype); | |
428 | rval = convert_pointer_to_real (binfo, rval); | |
429 | } | |
c76251c1 | 430 | else |
431 | rval | |
432 | = convert_to_pointer_force (build_pointer_type (target_type), rval); | |
6686e84d | 433 | rval = build1 (NOP_EXPR, type, rval); |
c76251c1 | 434 | TREE_CONSTANT (rval) = TREE_CONSTANT (TREE_OPERAND (rval, 0)); |
c23ebfdd | 435 | |
436 | /* If we created and initialized a new temporary variable, add the | |
437 | representation of that initialization to the RVAL. */ | |
438 | if (stmt_expr) | |
439 | rval = build (COMPOUND_EXPR, TREE_TYPE (rval), stmt_expr, rval); | |
440 | ||
441 | /* And return the result. */ | |
471086d6 | 442 | return rval; |
443 | } | |
444 | ||
519ba62c | 445 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
446 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
447 | for diagnostics. | |
448 | ||
449 | [dcl.init.ref] says that if an rvalue is used to | |
450 | initialize a reference, then the reference must be to a | |
451 | non-volatile const type. */ | |
452 | ||
453 | static void | |
454 | warn_ref_binding (reftype, intype, decl) | |
455 | tree reftype, intype, decl; | |
456 | { | |
457 | tree ttl = TREE_TYPE (reftype); | |
458 | ||
459 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) | |
460 | { | |
461 | const char *msg; | |
462 | ||
463 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
464 | msg = "initialization of volatile reference type `%#T' from rvalue of type `%T'"; | |
465 | else if (CP_TYPE_VOLATILE_P (ttl)) | |
466 | msg = "conversion to volatile reference type `%#T' from rvalue of type `%T'"; | |
467 | else if (decl) | |
468 | msg = "initialization of non-const reference type `%#T' from rvalue of type `%T'"; | |
469 | else | |
470 | msg = "conversion to non-const reference type `%#T' from rvalue of type `%T'"; | |
471 | ||
472 | cp_pedwarn (msg, reftype, intype); | |
473 | } | |
474 | } | |
475 | ||
471086d6 | 476 | /* For C++: Only need to do one-level references, but cannot |
477 | get tripped up on signed/unsigned differences. | |
478 | ||
d81e00a4 | 479 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
480 | initialized. It can be error_mark_node if we don't know the _DECL but | |
481 | we know it's an initialization. */ | |
471086d6 | 482 | |
471086d6 | 483 | tree |
d81e00a4 | 484 | convert_to_reference (reftype, expr, convtype, flags, decl) |
471086d6 | 485 | tree reftype, expr; |
d81e00a4 | 486 | int convtype, flags; |
487 | tree decl; | |
471086d6 | 488 | { |
489 | register tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); | |
490 | register tree intype = TREE_TYPE (expr); | |
471086d6 | 491 | tree rval = NULL_TREE; |
1a3f833b | 492 | tree rval_as_conversion = NULL_TREE; |
493 | int i; | |
494 | ||
cc4d0855 | 495 | if (TREE_CODE (type) == FUNCTION_TYPE && intype == unknown_type_node) |
496 | { | |
3effa7a7 | 497 | expr = instantiate_type (type, expr, |
ffe5bd74 | 498 | (flags & LOOKUP_COMPLAIN) |
499 | ? itf_complain : itf_none); | |
3effa7a7 | 500 | if (expr == error_mark_node) |
501 | return error_mark_node; | |
502 | ||
cc4d0855 | 503 | intype = TREE_TYPE (expr); |
504 | } | |
505 | ||
1a3f833b | 506 | if (TREE_CODE (intype) == REFERENCE_TYPE) |
507 | my_friendly_abort (364); | |
471086d6 | 508 | |
471086d6 | 509 | intype = TYPE_MAIN_VARIANT (intype); |
510 | ||
1a3f833b | 511 | i = comp_target_types (type, intype, 0); |
512 | ||
513 | if (i <= 0 && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) | |
514 | && ! (flags & LOOKUP_NO_CONVERSION)) | |
515 | { | |
516 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
517 | ||
0a4be248 | 518 | rval_as_conversion |
1c16607c | 519 | = build_type_conversion (reftype, expr, 1); |
1a3f833b | 520 | |
521 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
522 | && real_lvalue_p (rval_as_conversion)) | |
523 | { | |
524 | expr = rval_as_conversion; | |
525 | rval_as_conversion = NULL_TREE; | |
526 | intype = type; | |
527 | i = 1; | |
528 | } | |
529 | } | |
530 | ||
531 | if (((convtype & CONV_STATIC) && i == -1) | |
532 | || ((convtype & CONV_IMPLICIT) && i == 1)) | |
471086d6 | 533 | { |
471086d6 | 534 | if (flags & LOOKUP_COMPLAIN) |
535 | { | |
bc3887cf | 536 | tree ttl = TREE_TYPE (reftype); |
cb0ba4ec | 537 | tree ttr = lvalue_type (expr); |
471086d6 | 538 | |
519ba62c | 539 | if (! real_lvalue_p (expr)) |
540 | warn_ref_binding (reftype, intype, decl); | |
541 | ||
542 | if (! (convtype & CONV_CONST) | |
3e04bd45 | 543 | && !at_least_as_qualified_p (ttl, ttr)) |
caa99b15 | 544 | cp_pedwarn ("conversion from `%T' to `%T' discards qualifiers", |
545 | ttr, reftype); | |
0543e7a9 | 546 | } |
547 | ||
ca106ab1 | 548 | return build_up_reference (reftype, expr, flags, decl); |
471086d6 | 549 | } |
c07b1ad1 | 550 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 551 | { |
552 | /* When casting an lvalue to a reference type, just convert into | |
553 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 554 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 555 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 556 | |
3748625f | 557 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
e581f478 | 558 | meant. */ |
1a3f833b | 559 | if (TREE_CODE (intype) == POINTER_TYPE |
daf9ff67 | 560 | && (comptypes (TREE_TYPE (intype), type, |
561 | COMPARE_BASE | COMPARE_RELAXED ))) | |
905d4035 | 562 | cp_warning ("casting `%T' to `%T' does not dereference pointer", |
e581f478 | 563 | intype, reftype); |
564 | ||
0543e7a9 | 565 | rval = build_unary_op (ADDR_EXPR, expr, 0); |
566 | if (rval != error_mark_node) | |
985e9ee0 | 567 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
568 | rval, 0); | |
0543e7a9 | 569 | if (rval != error_mark_node) |
b0722fac | 570 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 571 | } |
0a4be248 | 572 | else |
860740a7 | 573 | { |
574 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
575 | "converting", 0, 0); | |
a66fe4cb | 576 | if (rval == NULL_TREE || rval == error_mark_node) |
577 | return rval; | |
519ba62c | 578 | warn_ref_binding (reftype, intype, decl); |
ca106ab1 | 579 | rval = build_up_reference (reftype, rval, flags, decl); |
860740a7 | 580 | } |
471086d6 | 581 | |
582 | if (rval) | |
583 | { | |
96624a9e | 584 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 585 | return rval; |
586 | } | |
587 | ||
1a3f833b | 588 | my_friendly_assert (TREE_CODE (intype) != OFFSET_TYPE, 189); |
471086d6 | 589 | |
b248d3f7 | 590 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 591 | cp_error ("cannot convert type `%T' to type `%T'", intype, reftype); |
b248d3f7 | 592 | |
471086d6 | 593 | if (flags & LOOKUP_SPECULATIVELY) |
594 | return NULL_TREE; | |
595 | ||
596 | return error_mark_node; | |
597 | } | |
598 | ||
599 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 600 | way down to its lowest form. */ |
601 | ||
471086d6 | 602 | tree |
603 | convert_from_reference (val) | |
604 | tree val; | |
605 | { | |
606 | tree type = TREE_TYPE (val); | |
607 | ||
608 | if (TREE_CODE (type) == OFFSET_TYPE) | |
609 | type = TREE_TYPE (type); | |
8c5c575d | 610 | if (TREE_CODE (type) == REFERENCE_TYPE) |
4d698345 | 611 | return build_indirect_ref (val, NULL); |
471086d6 | 612 | return val; |
613 | } | |
dbacd3bd | 614 | |
615 | /* Implicitly convert the lvalue EXPR to another lvalue of type TOTYPE, | |
616 | preserving cv-qualification. */ | |
617 | ||
618 | tree | |
619 | convert_lvalue (totype, expr) | |
620 | tree totype, expr; | |
621 | { | |
622 | totype = cp_build_qualified_type (totype, TYPE_QUALS (TREE_TYPE (expr))); | |
623 | totype = build_reference_type (totype); | |
624 | expr = convert_to_reference (totype, expr, CONV_IMPLICIT, LOOKUP_NORMAL, | |
625 | NULL_TREE); | |
626 | return convert_from_reference (expr); | |
627 | } | |
471086d6 | 628 | \f |
471086d6 | 629 | /* Call this when we know (for any reason) that expr is not, in fact, |
630 | zero. This routine is like convert_pointer_to, but it pays | |
631 | attention to which specific instance of what type we want to | |
632 | convert to. This routine should eventually become | |
633 | convert_to_pointer after all references to convert_to_pointer | |
634 | are removed. */ | |
96624a9e | 635 | |
471086d6 | 636 | tree |
637 | convert_pointer_to_real (binfo, expr) | |
638 | tree binfo, expr; | |
639 | { | |
640 | register tree intype = TREE_TYPE (expr); | |
641 | tree ptr_type; | |
642 | tree type, rval; | |
643 | ||
00d2b1b9 | 644 | if (intype == error_mark_node) |
645 | return error_mark_node; | |
646 | ||
471086d6 | 647 | if (TREE_CODE (binfo) == TREE_VEC) |
648 | type = BINFO_TYPE (binfo); | |
649 | else if (IS_AGGR_TYPE (binfo)) | |
650 | { | |
651 | type = binfo; | |
652 | } | |
653 | else | |
654 | { | |
655 | type = binfo; | |
656 | binfo = NULL_TREE; | |
657 | } | |
658 | ||
3e04bd45 | 659 | ptr_type = cp_build_qualified_type (type, |
3119c950 | 660 | cp_type_quals (TREE_TYPE (intype))); |
d2a15a12 | 661 | ptr_type = build_pointer_type (ptr_type); |
cf90626c | 662 | if (same_type_p (ptr_type, TYPE_MAIN_VARIANT (intype))) |
471086d6 | 663 | return expr; |
664 | ||
471086d6 | 665 | my_friendly_assert (!integer_zerop (expr), 191); |
666 | ||
0df40fee | 667 | intype = TYPE_MAIN_VARIANT (TREE_TYPE (intype)); |
471086d6 | 668 | if (TREE_CODE (type) == RECORD_TYPE |
0df40fee | 669 | && TREE_CODE (intype) == RECORD_TYPE |
670 | && type != intype) | |
471086d6 | 671 | { |
672 | tree path; | |
673 | int distance | |
0df40fee | 674 | = get_base_distance (binfo, intype, 0, &path); |
471086d6 | 675 | |
676 | /* This function shouldn't be called with unqualified arguments | |
677 | but if it is, give them an error message that they can read. */ | |
678 | if (distance < 0) | |
679 | { | |
905d4035 | 680 | cp_error ("cannot convert a pointer of type `%T' to a pointer of type `%T'", |
0df40fee | 681 | intype, type); |
471086d6 | 682 | |
683 | if (distance == -2) | |
905d4035 | 684 | cp_error ("because `%T' is an ambiguous base class", type); |
471086d6 | 685 | return error_mark_node; |
686 | } | |
687 | ||
688 | return build_vbase_path (PLUS_EXPR, ptr_type, expr, path, 1); | |
689 | } | |
690 | rval = build1 (NOP_EXPR, ptr_type, | |
691 | TREE_CODE (expr) == NOP_EXPR ? TREE_OPERAND (expr, 0) : expr); | |
692 | TREE_CONSTANT (rval) = TREE_CONSTANT (expr); | |
693 | return rval; | |
694 | } | |
695 | ||
696 | /* Call this when we know (for any reason) that expr is | |
697 | not, in fact, zero. This routine gets a type out of the first | |
698 | argument and uses it to search for the type to convert to. If there | |
699 | is more than one instance of that type in the expr, the conversion is | |
700 | ambiguous. This routine should eventually go away, and all | |
701 | callers should use convert_to_pointer_real. */ | |
96624a9e | 702 | |
471086d6 | 703 | tree |
704 | convert_pointer_to (binfo, expr) | |
705 | tree binfo, expr; | |
706 | { | |
c161288a | 707 | return convert_pointer_to_real (binfo, expr); |
471086d6 | 708 | } |
471086d6 | 709 | \f |
c4a8ac95 | 710 | /* C++ conversions, preference to static cast conversions. */ |
711 | ||
712 | tree | |
713 | cp_convert (type, expr) | |
714 | tree type, expr; | |
715 | { | |
716 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); | |
717 | } | |
718 | ||
b248d3f7 | 719 | /* Conversion... |
720 | ||
721 | FLAGS indicates how we should behave. */ | |
722 | ||
471086d6 | 723 | tree |
c4a8ac95 | 724 | ocp_convert (type, expr, convtype, flags) |
471086d6 | 725 | tree type, expr; |
d81e00a4 | 726 | int convtype, flags; |
471086d6 | 727 | { |
728 | register tree e = expr; | |
729 | register enum tree_code code = TREE_CODE (type); | |
730 | ||
b465397d | 731 | if (e == error_mark_node |
732 | || TREE_TYPE (e) == error_mark_node) | |
471086d6 | 733 | return error_mark_node; |
d81e00a4 | 734 | |
5b592939 | 735 | complete_type (type); |
736 | complete_type (TREE_TYPE (expr)); | |
737 | ||
1202e392 | 738 | e = decl_constant_value (e); |
7745052b | 739 | |
2133b374 | 740 | if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP) |
741 | /* Some internal structures (vtable_entry_type, sigtbl_ptr_type) | |
742 | don't go through finish_struct, so they don't have the synthesized | |
743 | constructors. So don't force a temporary. */ | |
744 | && TYPE_HAS_CONSTRUCTOR (type)) | |
1a3f833b | 745 | /* We need a new temporary; don't take this shortcut. */; |
746 | else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) | |
ca23ec64 | 747 | { |
daf9ff67 | 748 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 749 | /* The call to fold will not always remove the NOP_EXPR as |
750 | might be expected, since if one of the types is a typedef; | |
751 | the comparsion in fold is just equality of pointers, not a | |
f699c174 | 752 | call to comptypes. We don't call fold in this case because |
753 | that can result in infinite recursion; fold will call | |
754 | convert, which will call ocp_convert, etc. */ | |
755 | return e; | |
372e0e29 | 756 | /* For complex data types, we need to perform componentwise |
757 | conversion. */ | |
758 | else if (TREE_CODE (type) == COMPLEX_TYPE) | |
759 | return fold (convert_to_complex (type, e)); | |
ca23ec64 | 760 | else |
f699c174 | 761 | return fold (build1 (NOP_EXPR, type, e)); |
ca23ec64 | 762 | } |
763 | ||
d81e00a4 | 764 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 765 | { |
b1a8d4ce | 766 | e = convert_to_void (e, /*implicit=*/NULL); |
aeef2be5 | 767 | return e; |
95b2ac55 | 768 | } |
d81e00a4 | 769 | |
471086d6 | 770 | /* Just convert to the type of the member. */ |
771 | if (code == OFFSET_TYPE) | |
772 | { | |
773 | type = TREE_TYPE (type); | |
774 | code = TREE_CODE (type); | |
775 | } | |
776 | ||
f3ba5c6a | 777 | if (TREE_CODE (e) == OFFSET_REF) |
778 | e = resolve_offset_ref (e); | |
779 | ||
bb0726a1 | 780 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 781 | { |
617abf06 | 782 | tree intype = TREE_TYPE (e); |
02d7f858 | 783 | /* enum = enum, enum = int, enum = float, (enum)pointer are all |
784 | errors. */ | |
723d9ad3 | 785 | if (TREE_CODE (type) == ENUMERAL_TYPE |
02d7f858 | 786 | && ((ARITHMETIC_TYPE_P (intype) && ! (convtype & CONV_STATIC)) |
787 | || (TREE_CODE (intype) == POINTER_TYPE))) | |
471086d6 | 788 | { |
905d4035 | 789 | cp_pedwarn ("conversion from `%#T' to `%#T'", intype, type); |
471086d6 | 790 | |
791 | if (flag_pedantic_errors) | |
792 | return error_mark_node; | |
793 | } | |
f3ba5c6a | 794 | if (IS_AGGR_TYPE (intype)) |
471086d6 | 795 | { |
796 | tree rval; | |
1c16607c | 797 | rval = build_type_conversion (type, e, 1); |
6495357a | 798 | if (rval) |
799 | return rval; | |
b248d3f7 | 800 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 801 | cp_error ("`%#T' used where a `%T' was expected", intype, type); |
b248d3f7 | 802 | if (flags & LOOKUP_SPECULATIVELY) |
803 | return NULL_TREE; | |
471086d6 | 804 | return error_mark_node; |
805 | } | |
bb0726a1 | 806 | if (code == BOOLEAN_TYPE) |
e4ce2dc4 | 807 | { |
5b592939 | 808 | tree fn = NULL_TREE; |
809 | ||
e4ce2dc4 | 810 | /* Common Ada/Pascal programmer's mistake. We always warn |
811 | about this since it is so bad. */ | |
812 | if (TREE_CODE (expr) == FUNCTION_DECL) | |
5b592939 | 813 | fn = expr; |
814 | else if (TREE_CODE (expr) == ADDR_EXPR | |
815 | && TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL) | |
816 | fn = TREE_OPERAND (expr, 0); | |
1d2ca10c | 817 | if (fn && !DECL_WEAK (fn)) |
5b592939 | 818 | cp_warning ("the address of `%D', will always be `true'", fn); |
2e0e6579 | 819 | return cp_truthvalue_conversion (e); |
e4ce2dc4 | 820 | } |
471086d6 | 821 | return fold (convert_to_integer (type, e)); |
822 | } | |
74002e1d | 823 | if (code == POINTER_TYPE || code == REFERENCE_TYPE |
824 | || TYPE_PTRMEMFUNC_P (type)) | |
045ed8f8 | 825 | return fold (cp_convert_to_pointer (type, e, 0)); |
684b9d79 | 826 | if (code == VECTOR_TYPE) |
827 | return fold (convert_to_vector (type, e)); | |
c4a8ac95 | 828 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 829 | { |
830 | if (IS_AGGR_TYPE (TREE_TYPE (e))) | |
831 | { | |
832 | tree rval; | |
1c16607c | 833 | rval = build_type_conversion (type, e, 1); |
471086d6 | 834 | if (rval) |
835 | return rval; | |
836 | else | |
b248d3f7 | 837 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 838 | cp_error ("`%#T' used where a floating point value was expected", |
b248d3f7 | 839 | TREE_TYPE (e)); |
471086d6 | 840 | } |
c4a8ac95 | 841 | if (code == REAL_TYPE) |
842 | return fold (convert_to_real (type, e)); | |
843 | else if (code == COMPLEX_TYPE) | |
844 | return fold (convert_to_complex (type, e)); | |
471086d6 | 845 | } |
846 | ||
847 | /* New C++ semantics: since assignment is now based on | |
848 | memberwise copying, if the rhs type is derived from the | |
849 | lhs type, then we may still do a conversion. */ | |
850 | if (IS_AGGR_TYPE_CODE (code)) | |
851 | { | |
852 | tree dtype = TREE_TYPE (e); | |
c25194fd | 853 | tree ctor = NULL_TREE; |
471086d6 | 854 | |
471086d6 | 855 | dtype = TYPE_MAIN_VARIANT (dtype); |
856 | ||
471086d6 | 857 | /* Conversion between aggregate types. New C++ semantics allow |
858 | objects of derived type to be cast to objects of base type. | |
859 | Old semantics only allowed this between pointers. | |
860 | ||
861 | There may be some ambiguity between using a constructor | |
862 | vs. using a type conversion operator when both apply. */ | |
863 | ||
0a4be248 | 864 | ctor = e; |
860740a7 | 865 | |
8c18e707 | 866 | if (abstract_virtuals_error (NULL_TREE, type)) |
867 | return error_mark_node; | |
6cbb4197 | 868 | |
0a4be248 | 869 | if ((flags & LOOKUP_ONLYCONVERTING) |
870 | && ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 871 | /* For copy-initialization, first we create a temp of the proper type |
872 | with a user-defined conversion sequence, then we direct-initialize | |
873 | the target with the temp (see [dcl.init]). */ | |
874 | ctor = build_user_type_conversion (type, ctor, flags); | |
3eb89cd8 | 875 | else |
cfb46e1f | 876 | ctor = build_method_call (NULL_TREE, |
877 | complete_ctor_identifier, | |
d0d8836b | 878 | build_tree_list (NULL_TREE, ctor), |
0a4be248 | 879 | TYPE_BINFO (type), flags); |
880 | if (ctor) | |
881 | return build_cplus_new (type, ctor); | |
471086d6 | 882 | } |
883 | ||
617abf06 | 884 | /* If TYPE or TREE_TYPE (E) is not on the permanent_obstack, |
7745052b | 885 | then it won't be hashed and hence compare as not equal, |
471086d6 | 886 | even when it is. */ |
887 | if (code == ARRAY_TYPE | |
617abf06 | 888 | && TREE_TYPE (TREE_TYPE (e)) == TREE_TYPE (type) |
889 | && index_type_equal (TYPE_DOMAIN (TREE_TYPE (e)), TYPE_DOMAIN (type))) | |
890 | return e; | |
471086d6 | 891 | |
b248d3f7 | 892 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 893 | cp_error ("conversion from `%T' to non-scalar type `%T' requested", |
b248d3f7 | 894 | TREE_TYPE (expr), type); |
895 | if (flags & LOOKUP_SPECULATIVELY) | |
896 | return NULL_TREE; | |
471086d6 | 897 | return error_mark_node; |
898 | } | |
899 | ||
b1a8d4ce | 900 | /* When an expression is used in a void context, its value is discarded and |
901 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
902 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
903 | in a void context. The C++ standard does not define what an `access' to an | |
904 | object is, but there is reason to beleive that it is the lvalue to rvalue | |
905 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it | |
906 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
907 | indicates that volatile semantics should be the same between C and C++ | |
908 | where ever possible. C leaves it implementation defined as to what | |
909 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
910 | the volatile object `vp' points to, unless that is an incomplete type. For | |
911 | volatile references we do not do this interpretation, because that would | |
912 | make it impossible to ignore the reference return value from functions. We | |
913 | issue warnings in the confusing cases. | |
914 | ||
915 | IMPLICIT is tells us the context of an implicit void conversion. */ | |
916 | ||
917 | tree | |
918 | convert_to_void (expr, implicit) | |
919 | tree expr; | |
920 | const char *implicit; | |
921 | { | |
3d411d73 | 922 | if (expr == error_mark_node |
923 | || TREE_TYPE (expr) == error_mark_node) | |
924 | return error_mark_node; | |
b1a8d4ce | 925 | if (!TREE_TYPE (expr)) |
926 | return expr; | |
e3cfe3ce | 927 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 928 | return expr; |
929 | switch (TREE_CODE (expr)) | |
930 | { | |
931 | case COND_EXPR: | |
932 | { | |
933 | /* The two parts of a cond expr might be separate lvalues. */ | |
934 | tree op1 = TREE_OPERAND (expr,1); | |
935 | tree op2 = TREE_OPERAND (expr,2); | |
936 | tree new_op1 = convert_to_void (op1, implicit); | |
937 | tree new_op2 = convert_to_void (op2, implicit); | |
938 | ||
69773da0 | 939 | expr = build (COND_EXPR, void_type_node, |
940 | TREE_OPERAND (expr, 0), new_op1, new_op2); | |
b1a8d4ce | 941 | break; |
942 | } | |
943 | ||
944 | case COMPOUND_EXPR: | |
945 | { | |
946 | /* The second part of a compound expr contains the value. */ | |
947 | tree op1 = TREE_OPERAND (expr,1); | |
948 | tree new_op1 = convert_to_void (op1, implicit); | |
949 | ||
950 | if (new_op1 != op1) | |
e907a2e9 | 951 | { |
952 | tree t = build (COMPOUND_EXPR, TREE_TYPE (new_op1), | |
953 | TREE_OPERAND (expr, 0), new_op1); | |
954 | TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (expr); | |
955 | expr = t; | |
956 | } | |
957 | ||
b1a8d4ce | 958 | break; |
959 | } | |
960 | ||
961 | case NON_LVALUE_EXPR: | |
962 | case NOP_EXPR: | |
963 | /* These have already decayed to rvalue. */ | |
964 | break; | |
965 | ||
966 | case CALL_EXPR: /* we have a special meaning for volatile void fn() */ | |
967 | break; | |
968 | ||
969 | case INDIRECT_REF: | |
970 | { | |
971 | tree type = TREE_TYPE (expr); | |
972 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
973 | == REFERENCE_TYPE; | |
974 | int is_volatile = TYPE_VOLATILE (type); | |
4b72716d | 975 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 976 | |
977 | if (is_volatile && !is_complete) | |
978 | cp_warning ("object of incomplete type `%T' will not be accessed in %s", | |
979 | type, implicit ? implicit : "void context"); | |
980 | else if (is_reference && is_volatile) | |
981 | cp_warning ("object of type `%T' will not be accessed in %s", | |
982 | TREE_TYPE (TREE_OPERAND (expr, 0)), | |
983 | implicit ? implicit : "void context"); | |
984 | if (is_reference || !is_volatile || !is_complete) | |
985 | expr = TREE_OPERAND (expr, 0); | |
986 | ||
987 | break; | |
988 | } | |
989 | ||
990 | case VAR_DECL: | |
991 | { | |
992 | /* External variables might be incomplete. */ | |
993 | tree type = TREE_TYPE (expr); | |
4b72716d | 994 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 995 | |
996 | if (TYPE_VOLATILE (type) && !is_complete) | |
997 | cp_warning ("object `%E' of incomplete type `%T' will not be accessed in %s", | |
998 | expr, type, implicit ? implicit : "void context"); | |
999 | break; | |
1000 | } | |
d9f88785 | 1001 | |
1002 | case OFFSET_REF: | |
1003 | expr = resolve_offset_ref (expr); | |
1004 | break; | |
1005 | ||
b1a8d4ce | 1006 | default:; |
1007 | } | |
1008 | { | |
1009 | tree probe = expr; | |
1010 | ||
1011 | if (TREE_CODE (probe) == ADDR_EXPR) | |
1012 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 1013 | if (type_unknown_p (probe)) |
1014 | { | |
1015 | /* [over.over] enumerates the places where we can take the address | |
1016 | of an overloaded function, and this is not one of them. */ | |
1017 | cp_pedwarn ("%s cannot resolve address of overloaded function", | |
1018 | implicit ? implicit : "void cast"); | |
1019 | } | |
1020 | else if (implicit && probe == expr && is_overloaded_fn (probe)) | |
b1a8d4ce | 1021 | /* Only warn when there is no &. */ |
1022 | cp_warning ("%s is a reference, not call, to function `%E'", | |
2e0e6579 | 1023 | implicit, expr); |
b1a8d4ce | 1024 | } |
1025 | ||
e3cfe3ce | 1026 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 1027 | { |
1028 | /* FIXME: This is where we should check for expressions with no | |
1029 | effects. At the moment we do that in both build_x_component_expr | |
1030 | and expand_expr_stmt -- inconsistently too. For the moment | |
1031 | leave implicit void conversions unadorned so that expand_expr_stmt | |
1032 | has a chance of detecting some of the cases. */ | |
1033 | if (!implicit) | |
1034 | expr = build1 (CONVERT_EXPR, void_type_node, expr); | |
1035 | } | |
1036 | return expr; | |
1037 | } | |
1038 | ||
d81e00a4 | 1039 | /* Create an expression whose value is that of EXPR, |
1040 | converted to type TYPE. The TREE_TYPE of the value | |
1041 | is always TYPE. This function implements all reasonable | |
1042 | conversions; callers should filter out those that are | |
c4a8ac95 | 1043 | not permitted by the language being compiled. |
1044 | ||
1045 | Most of this routine is from build_reinterpret_cast. | |
1046 | ||
1047 | The backend cannot call cp_convert (what was convert) because | |
1048 | conversions to/from basetypes may involve memory references | |
1049 | (vbases) and adding or subtracting small values (multiple | |
1050 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 1051 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 1052 | |
1053 | Also, if we ever support range variables, we'll probably also have to | |
1054 | do a little bit more work. */ | |
d81e00a4 | 1055 | |
1056 | tree | |
1057 | convert (type, expr) | |
1058 | tree type, expr; | |
1059 | { | |
c4a8ac95 | 1060 | tree intype; |
1061 | ||
1062 | if (type == error_mark_node || expr == error_mark_node) | |
1063 | return error_mark_node; | |
1064 | ||
c4a8ac95 | 1065 | intype = TREE_TYPE (expr); |
1066 | ||
6686e84d | 1067 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
c4a8ac95 | 1068 | { |
1202e392 | 1069 | expr = decl_constant_value (expr); |
c4a8ac95 | 1070 | return fold (build1 (NOP_EXPR, type, expr)); |
1071 | } | |
1072 | ||
1073 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
1074 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); | |
d81e00a4 | 1075 | } |
1076 | ||
c4a8ac95 | 1077 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 1078 | are not normally allowed due to access restrictions |
1079 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 1080 | |
471086d6 | 1081 | tree |
a74e8896 | 1082 | convert_force (type, expr, convtype) |
471086d6 | 1083 | tree type; |
1084 | tree expr; | |
a74e8896 | 1085 | int convtype; |
471086d6 | 1086 | { |
1087 | register tree e = expr; | |
1088 | register enum tree_code code = TREE_CODE (type); | |
1089 | ||
1090 | if (code == REFERENCE_TYPE) | |
d81e00a4 | 1091 | return fold (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, |
1092 | NULL_TREE)); | |
471086d6 | 1093 | else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) |
1094 | e = convert_from_reference (e); | |
1095 | ||
1096 | if (code == POINTER_TYPE) | |
1097 | return fold (convert_to_pointer_force (type, e)); | |
1098 | ||
ac9386a0 | 1099 | /* From typeck.c convert_for_assignment */ |
471086d6 | 1100 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
1101 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
1102 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 1103 | || integer_zerop (e) |
1104 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1105 | && TYPE_PTRMEMFUNC_P (type)) |
1106 | { | |
96624a9e | 1107 | /* compatible pointer to member functions. */ |
ac9386a0 | 1108 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1); |
471086d6 | 1109 | } |
a74e8896 | 1110 | |
c4a8ac95 | 1111 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
471086d6 | 1112 | } |
1113 | ||
471086d6 | 1114 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1115 | exists, return the attempted conversion. This may | |
1116 | return ERROR_MARK_NODE if the conversion is not | |
1117 | allowed (references private members, etc). | |
1118 | If no conversion exists, NULL_TREE is returned. | |
1119 | ||
1120 | If (FOR_SURE & 1) is non-zero, then we allow this type conversion | |
1121 | to take place immediately. Otherwise, we build a SAVE_EXPR | |
ce28ee2e | 1122 | which can be evaluated if the results are ever needed. |
1123 | ||
1124 | Changes to this functions should be mirrored in user_harshness. | |
1125 | ||
1126 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit | |
1127 | object parameter, or by the second standard conversion sequence if | |
1128 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1129 | (jason 8/9/95) */ | |
471086d6 | 1130 | |
471086d6 | 1131 | tree |
1c16607c | 1132 | build_type_conversion (xtype, expr, for_sure) |
471086d6 | 1133 | tree xtype, expr; |
1134 | int for_sure; | |
1135 | { | |
1136 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1137 | into the required type. */ |
0a4be248 | 1138 | return build_user_type_conversion |
1139 | (xtype, expr, for_sure ? LOOKUP_NORMAL : 0); | |
471086d6 | 1140 | } |
1141 | ||
1e66592c | 1142 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1143 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
1144 | which indicates which types are suitable. If COMPLAIN is 1, complain | |
1145 | about ambiguity; otherwise, the caller will deal with it. */ | |
471086d6 | 1146 | |
1e66592c | 1147 | tree |
1148 | build_expr_type_conversion (desires, expr, complain) | |
1149 | int desires; | |
1150 | tree expr; | |
1151 | int complain; | |
471086d6 | 1152 | { |
1e66592c | 1153 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1154 | tree conv = NULL_TREE; |
bdd152ce | 1155 | tree winner = NULL_TREE; |
471086d6 | 1156 | |
954885ed | 1157 | if (expr == null_node |
1158 | && (desires & WANT_INT) | |
1159 | && !(desires & WANT_NULL)) | |
905d4035 | 1160 | cp_warning ("converting NULL to non-pointer type"); |
954885ed | 1161 | |
42b9ec6a | 1162 | if (TREE_CODE (expr) == OFFSET_REF) |
ce28ee2e | 1163 | expr = resolve_offset_ref (expr); |
1164 | expr = convert_from_reference (expr); | |
1165 | basetype = TREE_TYPE (expr); | |
471086d6 | 1166 | |
3d411d73 | 1167 | if (basetype == error_mark_node) |
1168 | return error_mark_node; | |
1169 | ||
bdd152ce | 1170 | if (! IS_AGGR_TYPE (basetype)) |
1171 | switch (TREE_CODE (basetype)) | |
1172 | { | |
1173 | case INTEGER_TYPE: | |
954885ed | 1174 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1175 | return expr; |
1176 | /* else fall through... */ | |
1177 | ||
1178 | case BOOLEAN_TYPE: | |
1179 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1180 | case ENUMERAL_TYPE: | |
1181 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1182 | case REAL_TYPE: | |
1183 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1184 | case POINTER_TYPE: | |
1185 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
985e9ee0 | 1186 | |
bdd152ce | 1187 | case FUNCTION_TYPE: |
1188 | case ARRAY_TYPE: | |
1189 | return (desires & WANT_POINTER) ? default_conversion (expr) | |
1190 | : NULL_TREE; | |
1191 | default: | |
1192 | return NULL_TREE; | |
1193 | } | |
1194 | ||
1195 | /* The code for conversions from class type is currently only used for | |
1196 | delete expressions. Other expressions are handled by build_new_op. */ | |
1197 | ||
1198 | if (! TYPE_HAS_CONVERSION (basetype)) | |
1199 | return NULL_TREE; | |
1200 | ||
1201 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) | |
1202 | { | |
1203 | int win = 0; | |
1204 | tree candidate; | |
1205 | tree cand = TREE_VALUE (conv); | |
1206 | ||
1207 | if (winner && winner == cand) | |
1208 | continue; | |
1209 | ||
1210 | candidate = TREE_TYPE (TREE_TYPE (cand)); | |
1211 | if (TREE_CODE (candidate) == REFERENCE_TYPE) | |
1212 | candidate = TREE_TYPE (candidate); | |
1213 | ||
1214 | switch (TREE_CODE (candidate)) | |
1215 | { | |
1216 | case BOOLEAN_TYPE: | |
1217 | case INTEGER_TYPE: | |
1218 | win = (desires & WANT_INT); break; | |
1219 | case ENUMERAL_TYPE: | |
1220 | win = (desires & WANT_ENUM); break; | |
1221 | case REAL_TYPE: | |
1222 | win = (desires & WANT_FLOAT); break; | |
1223 | case POINTER_TYPE: | |
1224 | win = (desires & WANT_POINTER); break; | |
1225 | ||
1226 | default: | |
1227 | break; | |
1228 | } | |
1229 | ||
1230 | if (win) | |
1231 | { | |
1232 | if (winner) | |
1233 | { | |
1234 | if (complain) | |
1235 | { | |
905d4035 | 1236 | cp_error ("ambiguous default type conversion from `%T'", |
bdd152ce | 1237 | basetype); |
905d4035 | 1238 | cp_error (" candidate conversions include `%D' and `%D'", |
bdd152ce | 1239 | winner, cand); |
1240 | } | |
1241 | return error_mark_node; | |
1242 | } | |
1243 | else | |
1244 | winner = cand; | |
1245 | } | |
1246 | } | |
1e66592c | 1247 | |
bdd152ce | 1248 | if (winner) |
1249 | { | |
1250 | tree type = TREE_TYPE (TREE_TYPE (winner)); | |
1251 | if (TREE_CODE (type) == REFERENCE_TYPE) | |
1252 | type = TREE_TYPE (type); | |
1253 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL); | |
471086d6 | 1254 | } |
1e66592c | 1255 | |
985e9ee0 | 1256 | return NULL_TREE; |
471086d6 | 1257 | } |
bc3887cf | 1258 | |
96624a9e | 1259 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1260 | ||
bc3887cf | 1261 | tree |
1262 | type_promotes_to (type) | |
1263 | tree type; | |
1264 | { | |
3e04bd45 | 1265 | int type_quals; |
ce28ee2e | 1266 | |
1267 | if (type == error_mark_node) | |
1268 | return error_mark_node; | |
1269 | ||
3119c950 | 1270 | type_quals = cp_type_quals (type); |
bc3887cf | 1271 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1272 | |
1273 | /* bool always promotes to int (not unsigned), even if it's the same | |
1274 | size. */ | |
028ea8b4 | 1275 | if (type == boolean_type_node) |
bb0726a1 | 1276 | type = integer_type_node; |
1277 | ||
1278 | /* Normally convert enums to int, but convert wide enums to something | |
1279 | wider. */ | |
1280 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
1281 | || type == wchar_type_node) | |
6c9497b1 | 1282 | { |
1283 | int precision = MAX (TYPE_PRECISION (type), | |
1284 | TYPE_PRECISION (integer_type_node)); | |
1285 | tree totype = type_for_size (precision, 0); | |
1286 | if (TREE_UNSIGNED (type) | |
1287 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) | |
1288 | type = type_for_size (precision, 1); | |
1289 | else | |
1290 | type = totype; | |
1291 | } | |
d7aeef06 | 1292 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1293 | { |
d0acef9e | 1294 | /* Retain unsignedness if really not getting bigger. */ |
bc3887cf | 1295 | if (TREE_UNSIGNED (type) |
d0acef9e | 1296 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1297 | type = unsigned_type_node; |
1298 | else | |
1299 | type = integer_type_node; | |
1300 | } | |
1301 | else if (type == float_type_node) | |
1302 | type = double_type_node; | |
1303 | ||
3e04bd45 | 1304 | return cp_build_qualified_type (type, type_quals); |
bc3887cf | 1305 | } |
668ae905 | 1306 | |
668ae905 | 1307 | /* The routines below this point are carefully written to conform to |
1308 | the standard. They use the same terminology, and follow the rules | |
1309 | closely. Although they are used only in pt.c at the moment, they | |
1310 | should presumably be used everywhere in the future. */ | |
1311 | ||
1146f179 | 1312 | /* Attempt to perform qualification conversions on EXPR to convert it |
1313 | to TYPE. Return the resulting expression, or error_mark_node if | |
1314 | the conversion was impossible. */ | |
1315 | ||
668ae905 | 1316 | tree |
1317 | perform_qualification_conversions (type, expr) | |
1318 | tree type; | |
1319 | tree expr; | |
1320 | { | |
213d2076 | 1321 | if (TREE_CODE (type) == POINTER_TYPE |
1322 | && TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE | |
1323 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (TREE_TYPE (expr)))) | |
1146f179 | 1324 | return build1 (NOP_EXPR, type, expr); |
1325 | else | |
1326 | return error_mark_node; | |
668ae905 | 1327 | } |