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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 | |
24054144 | 38 | static tree cp_convert_to_pointer PARAMS ((tree, tree)); |
39 | static tree convert_to_pointer_force PARAMS ((tree, tree)); | |
40 | static tree build_up_reference PARAMS ((tree, tree, int)); | |
71ccdfff | 41 | |
471086d6 | 42 | /* Change of width--truncation and extension of integers or reals-- |
43 | is represented with NOP_EXPR. Proper functioning of many things | |
44 | assumes that no other conversions can be NOP_EXPRs. | |
45 | ||
46 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
47 | Converting integer to real uses FLOAT_EXPR | |
48 | and real to integer uses FIX_TRUNC_EXPR. | |
49 | ||
50 | Here is a list of all the functions that assume that widening and | |
51 | narrowing is always done with a NOP_EXPR: | |
52 | In convert.c, convert_to_integer. | |
53 | In c-typeck.c, build_binary_op_nodefault (boolean ops), | |
54 | and truthvalue_conversion. | |
55 | In expr.c: expand_expr, for operands of a MULT_EXPR. | |
56 | In fold-const.c: fold. | |
57 | In tree.c: get_narrower and get_unwidened. | |
58 | ||
59 | C++: in multiple-inheritance, converting between pointers may involve | |
60 | adjusting them by a delta stored within the class definition. */ | |
61 | \f | |
62 | /* Subroutines of `convert'. */ | |
63 | ||
471086d6 | 64 | /* if converting pointer to pointer |
65 | if dealing with classes, check for derived->base or vice versa | |
66 | else if dealing with method pointers, delegate | |
67 | else convert blindly | |
68 | else if converting class, pass off to build_type_conversion | |
69 | else try C-style pointer conversion */ | |
96624a9e | 70 | |
471086d6 | 71 | static tree |
72 | cp_convert_to_pointer (type, expr) | |
73 | tree type, expr; | |
74 | { | |
75 | register tree intype = TREE_TYPE (expr); | |
74002e1d | 76 | register enum tree_code form; |
f82eeb87 | 77 | tree rval; |
74002e1d | 78 | |
96624a9e | 79 | if (IS_AGGR_TYPE (intype)) |
80 | { | |
96624a9e | 81 | intype = complete_type (intype); |
4b72716d | 82 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 83 | { |
905d4035 | 84 | cp_error ("can't convert from incomplete type `%T' to `%T'", |
96624a9e | 85 | intype, type); |
86 | return error_mark_node; | |
87 | } | |
88 | ||
1c16607c | 89 | rval = build_type_conversion (type, expr, 1); |
96624a9e | 90 | if (rval) |
91 | { | |
92 | if (rval == error_mark_node) | |
905d4035 | 93 | cp_error ("conversion of `%E' from `%T' to `%T' is ambiguous", |
96624a9e | 94 | expr, intype, type); |
95 | return rval; | |
96 | } | |
97 | } | |
98 | ||
860740a7 | 99 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 100 | if (TREE_CODE (type) == POINTER_TYPE |
101 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
860740a7 | 102 | || TYPE_MAIN_VARIANT (TREE_TYPE (type)) == void_type_node)) |
38281c46 | 103 | { |
104 | /* Allow an implicit this pointer for pointer to member | |
105 | functions. */ | |
860740a7 | 106 | if (TYPE_PTRMEMFUNC_P (intype)) |
38281c46 | 107 | { |
860740a7 | 108 | tree fntype = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (intype)); |
2917b86f | 109 | tree decl = maybe_dummy_object (TYPE_METHOD_BASETYPE (fntype), 0); |
38281c46 | 110 | expr = build (OFFSET_REF, fntype, decl, expr); |
111 | } | |
112 | ||
113 | if (TREE_CODE (expr) == OFFSET_REF | |
114 | && TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
115 | expr = resolve_offset_ref (expr); | |
116 | if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
117 | expr = build_addr_func (expr); | |
118 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) | |
119 | { | |
120 | if (TREE_CODE (TREE_TYPE (TREE_TYPE (expr))) == METHOD_TYPE) | |
121 | if (pedantic || warn_pmf2ptr) | |
905d4035 | 122 | cp_pedwarn ("converting from `%T' to `%T'", TREE_TYPE (expr), |
38281c46 | 123 | type); |
124 | return build1 (NOP_EXPR, type, expr); | |
125 | } | |
126 | intype = TREE_TYPE (expr); | |
127 | } | |
128 | ||
74002e1d | 129 | form = TREE_CODE (intype); |
130 | ||
2b77484d | 131 | if (POINTER_TYPE_P (intype)) |
471086d6 | 132 | { |
133 | intype = TYPE_MAIN_VARIANT (intype); | |
134 | ||
135 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 136 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 137 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
bccffb3a | 138 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
139 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
2edf445e | 140 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE |
141 | /* If EXPR is NULL, then we don't need to do any arithmetic | |
142 | to convert it: | |
143 | ||
144 | [conv.ptr] | |
145 | ||
146 | The null pointer value is converted to the null pointer | |
147 | value of the destination type. */ | |
148 | && !integer_zerop (expr)) | |
471086d6 | 149 | { |
150 | enum tree_code code = PLUS_EXPR; | |
151 | tree binfo = get_binfo (TREE_TYPE (type), TREE_TYPE (intype), 1); | |
152 | if (binfo == error_mark_node) | |
153 | return error_mark_node; | |
154 | if (binfo == NULL_TREE) | |
155 | { | |
156 | binfo = get_binfo (TREE_TYPE (intype), TREE_TYPE (type), 1); | |
157 | if (binfo == error_mark_node) | |
158 | return error_mark_node; | |
159 | code = MINUS_EXPR; | |
160 | } | |
161 | if (binfo) | |
162 | { | |
163 | if (TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (type)) | |
164 | || TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (intype)) | |
165 | || ! BINFO_OFFSET_ZEROP (binfo)) | |
166 | { | |
167 | /* Need to get the path we took. */ | |
168 | tree path; | |
169 | ||
170 | if (code == PLUS_EXPR) | |
985e9ee0 | 171 | get_base_distance (TREE_TYPE (type), TREE_TYPE (intype), |
172 | 0, &path); | |
471086d6 | 173 | else |
985e9ee0 | 174 | get_base_distance (TREE_TYPE (intype), TREE_TYPE (type), |
175 | 0, &path); | |
471086d6 | 176 | return build_vbase_path (code, type, expr, path, 0); |
177 | } | |
178 | } | |
179 | } | |
471086d6 | 180 | |
1c16607c | 181 | if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) |
bea7d742 | 182 | { |
a17aefa2 | 183 | tree b1; |
184 | tree b2; | |
185 | tree binfo; | |
186 | enum tree_code code; | |
187 | ||
188 | b1 = TYPE_OFFSET_BASETYPE (TREE_TYPE (type)); | |
189 | b2 = TYPE_OFFSET_BASETYPE (TREE_TYPE (intype)); | |
190 | binfo = get_binfo (b2, b1, 1); | |
fc9fc8d8 | 191 | |
bea7d742 | 192 | if (binfo == NULL_TREE) |
fc9fc8d8 | 193 | { |
194 | binfo = get_binfo (b1, b2, 1); | |
195 | code = MINUS_EXPR; | |
196 | } | |
a17aefa2 | 197 | else |
198 | code = PLUS_EXPR; | |
fc9fc8d8 | 199 | |
bea7d742 | 200 | if (binfo == error_mark_node) |
201 | return error_mark_node; | |
a17aefa2 | 202 | |
7045d67a | 203 | if (binfo_from_vbase (binfo)) |
204 | { | |
205 | cp_error ("conversion to `%T' from pointer to member of virtual base `%T'", | |
206 | type, intype); | |
207 | return error_mark_node; | |
208 | } | |
209 | ||
a17aefa2 | 210 | if (TREE_CODE (expr) == PTRMEM_CST) |
211 | expr = cplus_expand_constant (expr); | |
212 | ||
fc9fc8d8 | 213 | if (binfo && ! TREE_VIA_VIRTUAL (binfo)) |
902de8ed | 214 | expr = size_binop (code, convert (sizetype,expr), |
215 | BINFO_OFFSET (binfo)); | |
bea7d742 | 216 | } |
2b77484d | 217 | else if (TYPE_PTRMEMFUNC_P (type)) |
ce28ee2e | 218 | { |
905d4035 | 219 | cp_error ("cannot convert `%E' from type `%T' to type `%T'", |
ce28ee2e | 220 | expr, intype, type); |
221 | return error_mark_node; | |
222 | } | |
223 | ||
f82eeb87 | 224 | rval = build1 (NOP_EXPR, type, expr); |
225 | TREE_CONSTANT (rval) = TREE_CONSTANT (expr); | |
226 | return rval; | |
471086d6 | 227 | } |
2b77484d | 228 | else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)) |
7045d67a | 229 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
2b77484d | 230 | else if (TYPE_PTRMEMFUNC_P (intype)) |
231 | { | |
232 | cp_error ("cannot convert `%E' from type `%T' to type `%T'", | |
233 | expr, intype, type); | |
234 | return error_mark_node; | |
235 | } | |
471086d6 | 236 | |
237 | my_friendly_assert (form != OFFSET_TYPE, 186); | |
238 | ||
471086d6 | 239 | if (integer_zerop (expr)) |
240 | { | |
2b77484d | 241 | if (TYPE_PTRMEMFUNC_P (type)) |
f05d5d03 | 242 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
ad63a0fc | 243 | |
244 | if (flag_new_abi && TYPE_PTRMEM_P (type)) | |
245 | /* Under the new ABI, a NULL pointer-to-member is represented | |
246 | by -1, not by zero. */ | |
247 | expr = build_int_2 (-1, -1); | |
248 | else | |
249 | expr = build_int_2 (0, 0); | |
471086d6 | 250 | TREE_TYPE (expr) = type; |
251 | return expr; | |
252 | } | |
253 | ||
bb0726a1 | 254 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 255 | { |
c5aa1e92 | 256 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 257 | return build1 (CONVERT_EXPR, type, expr); |
c4a8ac95 | 258 | expr = cp_convert (type_for_size (POINTER_SIZE, 0), expr); |
471086d6 | 259 | /* Modes may be different but sizes should be the same. */ |
260 | if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
261 | != GET_MODE_SIZE (TYPE_MODE (type))) | |
262 | /* There is supposed to be some integral type | |
263 | that is the same width as a pointer. */ | |
264 | abort (); | |
265 | return convert_to_pointer (type, expr); | |
266 | } | |
267 | ||
cc4d0855 | 268 | if (type_unknown_p (expr)) |
269 | return instantiate_type (type, expr, 1); | |
270 | ||
905d4035 | 271 | cp_error ("cannot convert `%E' from type `%T' to type `%T'", |
471086d6 | 272 | expr, intype, type); |
273 | return error_mark_node; | |
274 | } | |
275 | ||
276 | /* Like convert, except permit conversions to take place which | |
277 | are not normally allowed due to access restrictions | |
278 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 279 | |
471086d6 | 280 | static tree |
281 | convert_to_pointer_force (type, expr) | |
282 | tree type, expr; | |
283 | { | |
284 | register tree intype = TREE_TYPE (expr); | |
285 | register enum tree_code form = TREE_CODE (intype); | |
286 | ||
287 | if (integer_zerop (expr)) | |
288 | { | |
471086d6 | 289 | expr = build_int_2 (0, 0); |
290 | TREE_TYPE (expr) = type; | |
291 | return expr; | |
292 | } | |
293 | ||
471086d6 | 294 | if (form == POINTER_TYPE) |
295 | { | |
296 | intype = TYPE_MAIN_VARIANT (intype); | |
297 | ||
298 | if (TYPE_MAIN_VARIANT (type) != intype | |
299 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
bccffb3a | 300 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
301 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
471086d6 | 302 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
303 | { | |
304 | enum tree_code code = PLUS_EXPR; | |
305 | tree path; | |
306 | int distance = get_base_distance (TREE_TYPE (type), | |
307 | TREE_TYPE (intype), 0, &path); | |
308 | if (distance == -2) | |
309 | { | |
310 | ambig: | |
905d4035 | 311 | cp_error ("type `%T' is ambiguous baseclass of `%s'", |
b0df6589 | 312 | TREE_TYPE (type), |
313 | TYPE_NAME_STRING (TREE_TYPE (intype))); | |
471086d6 | 314 | return error_mark_node; |
315 | } | |
316 | if (distance == -1) | |
317 | { | |
318 | distance = get_base_distance (TREE_TYPE (intype), | |
319 | TREE_TYPE (type), 0, &path); | |
320 | if (distance == -2) | |
321 | goto ambig; | |
322 | if (distance < 0) | |
323 | /* Doesn't need any special help from us. */ | |
324 | return build1 (NOP_EXPR, type, expr); | |
325 | ||
326 | code = MINUS_EXPR; | |
327 | } | |
328 | return build_vbase_path (code, type, expr, path, 0); | |
329 | } | |
471086d6 | 330 | } |
331 | ||
332 | return cp_convert_to_pointer (type, expr); | |
333 | } | |
334 | ||
335 | /* We are passing something to a function which requires a reference. | |
336 | The type we are interested in is in TYPE. The initial | |
337 | value we have to begin with is in ARG. | |
338 | ||
339 | FLAGS controls how we manage access checking. | |
c76251c1 | 340 | DIRECT_BIND in FLAGS controls how any temporaries are generated. */ |
96624a9e | 341 | |
471086d6 | 342 | static tree |
6a44e72e | 343 | build_up_reference (type, arg, flags) |
471086d6 | 344 | tree type, arg; |
6a44e72e | 345 | int flags; |
471086d6 | 346 | { |
c76251c1 | 347 | tree rval; |
0543e7a9 | 348 | tree argtype = TREE_TYPE (arg); |
471086d6 | 349 | tree target_type = TREE_TYPE (type); |
c23ebfdd | 350 | tree stmt_expr = NULL_TREE; |
471086d6 | 351 | |
352 | my_friendly_assert (TREE_CODE (type) == REFERENCE_TYPE, 187); | |
471086d6 | 353 | |
c76251c1 | 354 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 355 | { |
c23ebfdd | 356 | /* Create a new temporary variable. */ |
c76251c1 | 357 | tree targ = arg; |
38281c46 | 358 | if (toplevel_bindings_p ()) |
c76251c1 | 359 | arg = get_temp_name (argtype, 1); |
471086d6 | 360 | else |
361 | { | |
38281c46 | 362 | arg = pushdecl (build_decl (VAR_DECL, NULL_TREE, argtype)); |
363 | DECL_ARTIFICIAL (arg) = 1; | |
1ad432f2 | 364 | } |
c23ebfdd | 365 | |
366 | /* Process the initializer for the declaration. */ | |
38281c46 | 367 | DECL_INITIAL (arg) = targ; |
ce23987e | 368 | cp_finish_decl (arg, targ, NULL_TREE, |
011310f7 | 369 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 370 | } |
c76251c1 | 371 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
1d8e4310 | 372 | return get_target_expr (arg); |
1ad432f2 | 373 | |
b0df6589 | 374 | /* If we had a way to wrap this up, and say, if we ever needed it's |
375 | address, transform all occurrences of the register, into a memory | |
376 | reference we could win better. */ | |
c76251c1 | 377 | rval = build_unary_op (ADDR_EXPR, arg, 1); |
15e55420 | 378 | if (rval == error_mark_node) |
379 | return error_mark_node; | |
380 | ||
6686e84d | 381 | if ((flags & LOOKUP_PROTECT) |
382 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
383 | && IS_AGGR_TYPE (argtype) | |
384 | && IS_AGGR_TYPE (target_type)) | |
385 | { | |
386 | /* We go through get_binfo for the access control. */ | |
387 | tree binfo = get_binfo (target_type, argtype, 1); | |
388 | if (binfo == error_mark_node) | |
389 | return error_mark_node; | |
390 | if (binfo == NULL_TREE) | |
391 | return error_not_base_type (target_type, argtype); | |
392 | rval = convert_pointer_to_real (binfo, rval); | |
393 | } | |
c76251c1 | 394 | else |
395 | rval | |
396 | = convert_to_pointer_force (build_pointer_type (target_type), rval); | |
6686e84d | 397 | rval = build1 (NOP_EXPR, type, rval); |
c76251c1 | 398 | TREE_CONSTANT (rval) = TREE_CONSTANT (TREE_OPERAND (rval, 0)); |
c23ebfdd | 399 | |
400 | /* If we created and initialized a new temporary variable, add the | |
401 | representation of that initialization to the RVAL. */ | |
402 | if (stmt_expr) | |
403 | rval = build (COMPOUND_EXPR, TREE_TYPE (rval), stmt_expr, rval); | |
404 | ||
405 | /* And return the result. */ | |
471086d6 | 406 | return rval; |
407 | } | |
408 | ||
409 | /* For C++: Only need to do one-level references, but cannot | |
410 | get tripped up on signed/unsigned differences. | |
411 | ||
d81e00a4 | 412 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
413 | initialized. It can be error_mark_node if we don't know the _DECL but | |
414 | we know it's an initialization. */ | |
471086d6 | 415 | |
471086d6 | 416 | tree |
d81e00a4 | 417 | convert_to_reference (reftype, expr, convtype, flags, decl) |
471086d6 | 418 | tree reftype, expr; |
d81e00a4 | 419 | int convtype, flags; |
420 | tree decl; | |
471086d6 | 421 | { |
422 | register tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); | |
423 | register tree intype = TREE_TYPE (expr); | |
471086d6 | 424 | tree rval = NULL_TREE; |
1a3f833b | 425 | tree rval_as_conversion = NULL_TREE; |
426 | int i; | |
427 | ||
cc4d0855 | 428 | if (TREE_CODE (type) == FUNCTION_TYPE && intype == unknown_type_node) |
429 | { | |
3effa7a7 | 430 | expr = instantiate_type (type, expr, |
431 | (flags & LOOKUP_COMPLAIN) != 0); | |
432 | if (expr == error_mark_node) | |
433 | return error_mark_node; | |
434 | ||
cc4d0855 | 435 | intype = TREE_TYPE (expr); |
436 | } | |
437 | ||
1a3f833b | 438 | if (TREE_CODE (intype) == REFERENCE_TYPE) |
439 | my_friendly_abort (364); | |
471086d6 | 440 | |
471086d6 | 441 | intype = TYPE_MAIN_VARIANT (intype); |
442 | ||
1a3f833b | 443 | i = comp_target_types (type, intype, 0); |
444 | ||
445 | if (i <= 0 && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) | |
446 | && ! (flags & LOOKUP_NO_CONVERSION)) | |
447 | { | |
448 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
449 | ||
0a4be248 | 450 | rval_as_conversion |
1c16607c | 451 | = build_type_conversion (reftype, expr, 1); |
1a3f833b | 452 | |
453 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
454 | && real_lvalue_p (rval_as_conversion)) | |
455 | { | |
456 | expr = rval_as_conversion; | |
457 | rval_as_conversion = NULL_TREE; | |
458 | intype = type; | |
459 | i = 1; | |
460 | } | |
461 | } | |
462 | ||
463 | if (((convtype & CONV_STATIC) && i == -1) | |
464 | || ((convtype & CONV_IMPLICIT) && i == 1)) | |
471086d6 | 465 | { |
471086d6 | 466 | if (flags & LOOKUP_COMPLAIN) |
467 | { | |
bc3887cf | 468 | tree ttl = TREE_TYPE (reftype); |
cb0ba4ec | 469 | tree ttr = lvalue_type (expr); |
471086d6 | 470 | |
21a6dc86 | 471 | /* [dcl.init.ref] says that if an rvalue is used to |
472 | initialize a reference, then the reference must be to a | |
473 | non-volatile const type. */ | |
474 | if (! real_lvalue_p (expr) | |
3e04bd45 | 475 | && !CP_TYPE_CONST_NON_VOLATILE_P (ttl)) |
bc3887cf | 476 | { |
e1721763 | 477 | const char *msg; |
21a6dc86 | 478 | |
3e04bd45 | 479 | if (CP_TYPE_VOLATILE_P (ttl) && decl) |
21a6dc86 | 480 | msg = "initialization of volatile reference type `%#T'"; |
3e04bd45 | 481 | else if (CP_TYPE_VOLATILE_P (ttl)) |
21a6dc86 | 482 | msg = "conversion to volatile reference type `%#T'"; |
483 | else if (decl) | |
484 | msg = "initialization of non-const reference type `%#T'"; | |
d81e00a4 | 485 | else |
21a6dc86 | 486 | msg = "conversion to non-const reference type `%#T'"; |
487 | ||
caa99b15 | 488 | cp_pedwarn (msg, reftype); |
489 | cp_pedwarn ("from rvalue of type `%T'", intype); | |
bc3887cf | 490 | } |
3e04bd45 | 491 | else if (! (convtype & CONV_CONST) |
492 | && !at_least_as_qualified_p (ttl, ttr)) | |
caa99b15 | 493 | cp_pedwarn ("conversion from `%T' to `%T' discards qualifiers", |
494 | ttr, reftype); | |
0543e7a9 | 495 | } |
496 | ||
6a44e72e | 497 | return build_up_reference (reftype, expr, flags); |
471086d6 | 498 | } |
c07b1ad1 | 499 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 500 | { |
501 | /* When casting an lvalue to a reference type, just convert into | |
502 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 503 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 504 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 505 | |
3748625f | 506 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
e581f478 | 507 | meant. */ |
1a3f833b | 508 | if (TREE_CODE (intype) == POINTER_TYPE |
daf9ff67 | 509 | && (comptypes (TREE_TYPE (intype), type, |
510 | COMPARE_BASE | COMPARE_RELAXED ))) | |
905d4035 | 511 | cp_warning ("casting `%T' to `%T' does not dereference pointer", |
e581f478 | 512 | intype, reftype); |
513 | ||
0543e7a9 | 514 | rval = build_unary_op (ADDR_EXPR, expr, 0); |
515 | if (rval != error_mark_node) | |
985e9ee0 | 516 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
517 | rval, 0); | |
0543e7a9 | 518 | if (rval != error_mark_node) |
b0722fac | 519 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 520 | } |
0a4be248 | 521 | else |
860740a7 | 522 | { |
523 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
524 | "converting", 0, 0); | |
a66fe4cb | 525 | if (rval == NULL_TREE || rval == error_mark_node) |
526 | return rval; | |
6a44e72e | 527 | rval = build_up_reference (reftype, rval, flags); |
860740a7 | 528 | |
3e04bd45 | 529 | if (rval && ! CP_TYPE_CONST_P (TREE_TYPE (reftype))) |
905d4035 | 530 | cp_pedwarn ("initializing non-const `%T' with `%T' will use a temporary", |
860740a7 | 531 | reftype, intype); |
532 | } | |
471086d6 | 533 | |
534 | if (rval) | |
535 | { | |
96624a9e | 536 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 537 | return rval; |
538 | } | |
539 | ||
1a3f833b | 540 | my_friendly_assert (TREE_CODE (intype) != OFFSET_TYPE, 189); |
471086d6 | 541 | |
b248d3f7 | 542 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 543 | cp_error ("cannot convert type `%T' to type `%T'", intype, reftype); |
b248d3f7 | 544 | |
471086d6 | 545 | if (flags & LOOKUP_SPECULATIVELY) |
546 | return NULL_TREE; | |
547 | ||
548 | return error_mark_node; | |
549 | } | |
550 | ||
551 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 552 | way down to its lowest form. */ |
553 | ||
471086d6 | 554 | tree |
555 | convert_from_reference (val) | |
556 | tree val; | |
557 | { | |
558 | tree type = TREE_TYPE (val); | |
559 | ||
560 | if (TREE_CODE (type) == OFFSET_TYPE) | |
561 | type = TREE_TYPE (type); | |
8c5c575d | 562 | if (TREE_CODE (type) == REFERENCE_TYPE) |
563 | return build_indirect_ref (val, NULL_PTR); | |
471086d6 | 564 | return val; |
565 | } | |
566 | \f | |
471086d6 | 567 | /* Call this when we know (for any reason) that expr is not, in fact, |
568 | zero. This routine is like convert_pointer_to, but it pays | |
569 | attention to which specific instance of what type we want to | |
570 | convert to. This routine should eventually become | |
571 | convert_to_pointer after all references to convert_to_pointer | |
572 | are removed. */ | |
96624a9e | 573 | |
471086d6 | 574 | tree |
575 | convert_pointer_to_real (binfo, expr) | |
576 | tree binfo, expr; | |
577 | { | |
578 | register tree intype = TREE_TYPE (expr); | |
579 | tree ptr_type; | |
580 | tree type, rval; | |
581 | ||
00d2b1b9 | 582 | if (intype == error_mark_node) |
583 | return error_mark_node; | |
584 | ||
471086d6 | 585 | if (TREE_CODE (binfo) == TREE_VEC) |
586 | type = BINFO_TYPE (binfo); | |
587 | else if (IS_AGGR_TYPE (binfo)) | |
588 | { | |
589 | type = binfo; | |
590 | } | |
591 | else | |
592 | { | |
593 | type = binfo; | |
594 | binfo = NULL_TREE; | |
595 | } | |
596 | ||
3e04bd45 | 597 | ptr_type = cp_build_qualified_type (type, |
598 | CP_TYPE_QUALS (TREE_TYPE (intype))); | |
d2a15a12 | 599 | ptr_type = build_pointer_type (ptr_type); |
cf90626c | 600 | if (same_type_p (ptr_type, TYPE_MAIN_VARIANT (intype))) |
471086d6 | 601 | return expr; |
602 | ||
471086d6 | 603 | my_friendly_assert (!integer_zerop (expr), 191); |
604 | ||
0df40fee | 605 | intype = TYPE_MAIN_VARIANT (TREE_TYPE (intype)); |
471086d6 | 606 | if (TREE_CODE (type) == RECORD_TYPE |
0df40fee | 607 | && TREE_CODE (intype) == RECORD_TYPE |
608 | && type != intype) | |
471086d6 | 609 | { |
610 | tree path; | |
611 | int distance | |
0df40fee | 612 | = get_base_distance (binfo, intype, 0, &path); |
471086d6 | 613 | |
614 | /* This function shouldn't be called with unqualified arguments | |
615 | but if it is, give them an error message that they can read. */ | |
616 | if (distance < 0) | |
617 | { | |
905d4035 | 618 | cp_error ("cannot convert a pointer of type `%T' to a pointer of type `%T'", |
0df40fee | 619 | intype, type); |
471086d6 | 620 | |
621 | if (distance == -2) | |
905d4035 | 622 | cp_error ("because `%T' is an ambiguous base class", type); |
471086d6 | 623 | return error_mark_node; |
624 | } | |
625 | ||
626 | return build_vbase_path (PLUS_EXPR, ptr_type, expr, path, 1); | |
627 | } | |
628 | rval = build1 (NOP_EXPR, ptr_type, | |
629 | TREE_CODE (expr) == NOP_EXPR ? TREE_OPERAND (expr, 0) : expr); | |
630 | TREE_CONSTANT (rval) = TREE_CONSTANT (expr); | |
631 | return rval; | |
632 | } | |
633 | ||
634 | /* Call this when we know (for any reason) that expr is | |
635 | not, in fact, zero. This routine gets a type out of the first | |
636 | argument and uses it to search for the type to convert to. If there | |
637 | is more than one instance of that type in the expr, the conversion is | |
638 | ambiguous. This routine should eventually go away, and all | |
639 | callers should use convert_to_pointer_real. */ | |
96624a9e | 640 | |
471086d6 | 641 | tree |
642 | convert_pointer_to (binfo, expr) | |
643 | tree binfo, expr; | |
644 | { | |
c161288a | 645 | return convert_pointer_to_real (binfo, expr); |
471086d6 | 646 | } |
471086d6 | 647 | \f |
c4a8ac95 | 648 | /* C++ conversions, preference to static cast conversions. */ |
649 | ||
650 | tree | |
651 | cp_convert (type, expr) | |
652 | tree type, expr; | |
653 | { | |
654 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); | |
655 | } | |
656 | ||
b248d3f7 | 657 | /* Conversion... |
658 | ||
659 | FLAGS indicates how we should behave. */ | |
660 | ||
471086d6 | 661 | tree |
c4a8ac95 | 662 | ocp_convert (type, expr, convtype, flags) |
471086d6 | 663 | tree type, expr; |
d81e00a4 | 664 | int convtype, flags; |
471086d6 | 665 | { |
666 | register tree e = expr; | |
667 | register enum tree_code code = TREE_CODE (type); | |
668 | ||
b465397d | 669 | if (e == error_mark_node |
670 | || TREE_TYPE (e) == error_mark_node) | |
471086d6 | 671 | return error_mark_node; |
d81e00a4 | 672 | |
5b592939 | 673 | complete_type (type); |
674 | complete_type (TREE_TYPE (expr)); | |
675 | ||
7745052b | 676 | if (TREE_READONLY_DECL_P (e)) |
677 | e = decl_constant_value (e); | |
678 | ||
2133b374 | 679 | if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP) |
680 | /* Some internal structures (vtable_entry_type, sigtbl_ptr_type) | |
681 | don't go through finish_struct, so they don't have the synthesized | |
682 | constructors. So don't force a temporary. */ | |
683 | && TYPE_HAS_CONSTRUCTOR (type)) | |
1a3f833b | 684 | /* We need a new temporary; don't take this shortcut. */; |
685 | else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) | |
ca23ec64 | 686 | { |
daf9ff67 | 687 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 688 | /* The call to fold will not always remove the NOP_EXPR as |
689 | might be expected, since if one of the types is a typedef; | |
690 | the comparsion in fold is just equality of pointers, not a | |
f699c174 | 691 | call to comptypes. We don't call fold in this case because |
692 | that can result in infinite recursion; fold will call | |
693 | convert, which will call ocp_convert, etc. */ | |
694 | return e; | |
ca23ec64 | 695 | else |
f699c174 | 696 | return fold (build1 (NOP_EXPR, type, e)); |
ca23ec64 | 697 | } |
698 | ||
d81e00a4 | 699 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 700 | { |
b1a8d4ce | 701 | e = convert_to_void (e, /*implicit=*/NULL); |
aeef2be5 | 702 | return e; |
95b2ac55 | 703 | } |
d81e00a4 | 704 | |
471086d6 | 705 | /* Just convert to the type of the member. */ |
706 | if (code == OFFSET_TYPE) | |
707 | { | |
708 | type = TREE_TYPE (type); | |
709 | code = TREE_CODE (type); | |
710 | } | |
711 | ||
f3ba5c6a | 712 | if (TREE_CODE (e) == OFFSET_REF) |
713 | e = resolve_offset_ref (e); | |
714 | ||
bb0726a1 | 715 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 716 | { |
617abf06 | 717 | tree intype = TREE_TYPE (e); |
02d7f858 | 718 | /* enum = enum, enum = int, enum = float, (enum)pointer are all |
719 | errors. */ | |
723d9ad3 | 720 | if (TREE_CODE (type) == ENUMERAL_TYPE |
02d7f858 | 721 | && ((ARITHMETIC_TYPE_P (intype) && ! (convtype & CONV_STATIC)) |
722 | || (TREE_CODE (intype) == POINTER_TYPE))) | |
471086d6 | 723 | { |
905d4035 | 724 | cp_pedwarn ("conversion from `%#T' to `%#T'", intype, type); |
471086d6 | 725 | |
726 | if (flag_pedantic_errors) | |
727 | return error_mark_node; | |
728 | } | |
f3ba5c6a | 729 | if (IS_AGGR_TYPE (intype)) |
471086d6 | 730 | { |
731 | tree rval; | |
1c16607c | 732 | rval = build_type_conversion (type, e, 1); |
6495357a | 733 | if (rval) |
734 | return rval; | |
b248d3f7 | 735 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 736 | cp_error ("`%#T' used where a `%T' was expected", intype, type); |
b248d3f7 | 737 | if (flags & LOOKUP_SPECULATIVELY) |
738 | return NULL_TREE; | |
471086d6 | 739 | return error_mark_node; |
740 | } | |
bb0726a1 | 741 | if (code == BOOLEAN_TYPE) |
e4ce2dc4 | 742 | { |
5b592939 | 743 | tree fn = NULL_TREE; |
744 | ||
e4ce2dc4 | 745 | /* Common Ada/Pascal programmer's mistake. We always warn |
746 | about this since it is so bad. */ | |
747 | if (TREE_CODE (expr) == FUNCTION_DECL) | |
5b592939 | 748 | fn = expr; |
749 | else if (TREE_CODE (expr) == ADDR_EXPR | |
750 | && TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL) | |
751 | fn = TREE_OPERAND (expr, 0); | |
752 | if (fn) | |
753 | cp_warning ("the address of `%D', will always be `true'", fn); | |
e4ce2dc4 | 754 | return truthvalue_conversion (e); |
755 | } | |
471086d6 | 756 | return fold (convert_to_integer (type, e)); |
757 | } | |
74002e1d | 758 | if (code == POINTER_TYPE || code == REFERENCE_TYPE |
759 | || TYPE_PTRMEMFUNC_P (type)) | |
471086d6 | 760 | return fold (cp_convert_to_pointer (type, e)); |
c4a8ac95 | 761 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 762 | { |
763 | if (IS_AGGR_TYPE (TREE_TYPE (e))) | |
764 | { | |
765 | tree rval; | |
1c16607c | 766 | rval = build_type_conversion (type, e, 1); |
471086d6 | 767 | if (rval) |
768 | return rval; | |
769 | else | |
b248d3f7 | 770 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 771 | cp_error ("`%#T' used where a floating point value was expected", |
b248d3f7 | 772 | TREE_TYPE (e)); |
471086d6 | 773 | } |
c4a8ac95 | 774 | if (code == REAL_TYPE) |
775 | return fold (convert_to_real (type, e)); | |
776 | else if (code == COMPLEX_TYPE) | |
777 | return fold (convert_to_complex (type, e)); | |
471086d6 | 778 | } |
779 | ||
780 | /* New C++ semantics: since assignment is now based on | |
781 | memberwise copying, if the rhs type is derived from the | |
782 | lhs type, then we may still do a conversion. */ | |
783 | if (IS_AGGR_TYPE_CODE (code)) | |
784 | { | |
785 | tree dtype = TREE_TYPE (e); | |
c25194fd | 786 | tree ctor = NULL_TREE; |
471086d6 | 787 | |
471086d6 | 788 | dtype = TYPE_MAIN_VARIANT (dtype); |
789 | ||
471086d6 | 790 | /* Conversion between aggregate types. New C++ semantics allow |
791 | objects of derived type to be cast to objects of base type. | |
792 | Old semantics only allowed this between pointers. | |
793 | ||
794 | There may be some ambiguity between using a constructor | |
795 | vs. using a type conversion operator when both apply. */ | |
796 | ||
0a4be248 | 797 | ctor = e; |
860740a7 | 798 | |
8c18e707 | 799 | if (abstract_virtuals_error (NULL_TREE, type)) |
800 | return error_mark_node; | |
6cbb4197 | 801 | |
0a4be248 | 802 | if ((flags & LOOKUP_ONLYCONVERTING) |
803 | && ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 804 | /* For copy-initialization, first we create a temp of the proper type |
805 | with a user-defined conversion sequence, then we direct-initialize | |
806 | the target with the temp (see [dcl.init]). */ | |
807 | ctor = build_user_type_conversion (type, ctor, flags); | |
0a4be248 | 808 | if (ctor) |
cfb46e1f | 809 | ctor = build_method_call (NULL_TREE, |
810 | complete_ctor_identifier, | |
d0d8836b | 811 | build_tree_list (NULL_TREE, ctor), |
0a4be248 | 812 | TYPE_BINFO (type), flags); |
813 | if (ctor) | |
814 | return build_cplus_new (type, ctor); | |
471086d6 | 815 | } |
816 | ||
617abf06 | 817 | /* If TYPE or TREE_TYPE (E) is not on the permanent_obstack, |
7745052b | 818 | then it won't be hashed and hence compare as not equal, |
471086d6 | 819 | even when it is. */ |
820 | if (code == ARRAY_TYPE | |
617abf06 | 821 | && TREE_TYPE (TREE_TYPE (e)) == TREE_TYPE (type) |
822 | && index_type_equal (TYPE_DOMAIN (TREE_TYPE (e)), TYPE_DOMAIN (type))) | |
823 | return e; | |
471086d6 | 824 | |
b248d3f7 | 825 | if (flags & LOOKUP_COMPLAIN) |
905d4035 | 826 | cp_error ("conversion from `%T' to non-scalar type `%T' requested", |
b248d3f7 | 827 | TREE_TYPE (expr), type); |
828 | if (flags & LOOKUP_SPECULATIVELY) | |
829 | return NULL_TREE; | |
471086d6 | 830 | return error_mark_node; |
831 | } | |
832 | ||
b1a8d4ce | 833 | /* When an expression is used in a void context, its value is discarded and |
834 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
835 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
836 | in a void context. The C++ standard does not define what an `access' to an | |
837 | object is, but there is reason to beleive that it is the lvalue to rvalue | |
838 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it | |
839 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
840 | indicates that volatile semantics should be the same between C and C++ | |
841 | where ever possible. C leaves it implementation defined as to what | |
842 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
843 | the volatile object `vp' points to, unless that is an incomplete type. For | |
844 | volatile references we do not do this interpretation, because that would | |
845 | make it impossible to ignore the reference return value from functions. We | |
846 | issue warnings in the confusing cases. | |
847 | ||
848 | IMPLICIT is tells us the context of an implicit void conversion. */ | |
849 | ||
850 | tree | |
851 | convert_to_void (expr, implicit) | |
852 | tree expr; | |
853 | const char *implicit; | |
854 | { | |
3d411d73 | 855 | if (expr == error_mark_node |
856 | || TREE_TYPE (expr) == error_mark_node) | |
857 | return error_mark_node; | |
b1a8d4ce | 858 | if (!TREE_TYPE (expr)) |
859 | return expr; | |
860 | if (same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (expr)), void_type_node)) | |
861 | return expr; | |
862 | switch (TREE_CODE (expr)) | |
863 | { | |
864 | case COND_EXPR: | |
865 | { | |
866 | /* The two parts of a cond expr might be separate lvalues. */ | |
867 | tree op1 = TREE_OPERAND (expr,1); | |
868 | tree op2 = TREE_OPERAND (expr,2); | |
869 | tree new_op1 = convert_to_void (op1, implicit); | |
870 | tree new_op2 = convert_to_void (op2, implicit); | |
871 | ||
872 | if (new_op1 != op1 || new_op2 != op2) | |
873 | expr = build (COND_EXPR, | |
874 | implicit ? TREE_TYPE (expr) : void_type_node, | |
875 | TREE_OPERAND (expr, 0), new_op1, new_op2); | |
876 | break; | |
877 | } | |
878 | ||
879 | case COMPOUND_EXPR: | |
880 | { | |
881 | /* The second part of a compound expr contains the value. */ | |
882 | tree op1 = TREE_OPERAND (expr,1); | |
883 | tree new_op1 = convert_to_void (op1, implicit); | |
884 | ||
885 | if (new_op1 != op1) | |
886 | expr = build (COMPOUND_EXPR, TREE_TYPE (new_op1), | |
887 | TREE_OPERAND (expr, 0), new_op1); | |
888 | break; | |
889 | } | |
890 | ||
891 | case NON_LVALUE_EXPR: | |
892 | case NOP_EXPR: | |
893 | /* These have already decayed to rvalue. */ | |
894 | break; | |
895 | ||
896 | case CALL_EXPR: /* we have a special meaning for volatile void fn() */ | |
897 | break; | |
898 | ||
899 | case INDIRECT_REF: | |
900 | { | |
901 | tree type = TREE_TYPE (expr); | |
902 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
903 | == REFERENCE_TYPE; | |
904 | int is_volatile = TYPE_VOLATILE (type); | |
4b72716d | 905 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 906 | |
907 | if (is_volatile && !is_complete) | |
908 | cp_warning ("object of incomplete type `%T' will not be accessed in %s", | |
909 | type, implicit ? implicit : "void context"); | |
910 | else if (is_reference && is_volatile) | |
911 | cp_warning ("object of type `%T' will not be accessed in %s", | |
912 | TREE_TYPE (TREE_OPERAND (expr, 0)), | |
913 | implicit ? implicit : "void context"); | |
914 | if (is_reference || !is_volatile || !is_complete) | |
915 | expr = TREE_OPERAND (expr, 0); | |
916 | ||
917 | break; | |
918 | } | |
919 | ||
920 | case VAR_DECL: | |
921 | { | |
922 | /* External variables might be incomplete. */ | |
923 | tree type = TREE_TYPE (expr); | |
4b72716d | 924 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 925 | |
926 | if (TYPE_VOLATILE (type) && !is_complete) | |
927 | cp_warning ("object `%E' of incomplete type `%T' will not be accessed in %s", | |
928 | expr, type, implicit ? implicit : "void context"); | |
929 | break; | |
930 | } | |
931 | ||
932 | default:; | |
933 | } | |
934 | { | |
935 | tree probe = expr; | |
936 | ||
937 | if (TREE_CODE (probe) == ADDR_EXPR) | |
938 | probe = TREE_OPERAND (expr, 0); | |
939 | if (!is_overloaded_fn (probe)) | |
940 | ;/* OK */ | |
941 | else if (really_overloaded_fn (probe)) | |
942 | { | |
943 | /* [over.over] enumerates the places where we can take the address | |
944 | of an overloaded function, and this is not one of them. */ | |
945 | cp_pedwarn ("%s has no context for overloaded function name `%E'", | |
946 | implicit ? implicit : "void cast", expr); | |
947 | } | |
948 | else if (implicit && probe == expr) | |
949 | /* Only warn when there is no &. */ | |
950 | cp_warning ("%s is a reference, not call, to function `%E'", | |
951 | implicit, expr); | |
952 | } | |
953 | ||
954 | if (expr != error_mark_node | |
955 | && !same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (expr)), void_type_node)) | |
956 | { | |
957 | /* FIXME: This is where we should check for expressions with no | |
958 | effects. At the moment we do that in both build_x_component_expr | |
959 | and expand_expr_stmt -- inconsistently too. For the moment | |
960 | leave implicit void conversions unadorned so that expand_expr_stmt | |
961 | has a chance of detecting some of the cases. */ | |
962 | if (!implicit) | |
963 | expr = build1 (CONVERT_EXPR, void_type_node, expr); | |
964 | } | |
965 | return expr; | |
966 | } | |
967 | ||
d81e00a4 | 968 | /* Create an expression whose value is that of EXPR, |
969 | converted to type TYPE. The TREE_TYPE of the value | |
970 | is always TYPE. This function implements all reasonable | |
971 | conversions; callers should filter out those that are | |
c4a8ac95 | 972 | not permitted by the language being compiled. |
973 | ||
974 | Most of this routine is from build_reinterpret_cast. | |
975 | ||
976 | The backend cannot call cp_convert (what was convert) because | |
977 | conversions to/from basetypes may involve memory references | |
978 | (vbases) and adding or subtracting small values (multiple | |
979 | inheritance), but it calls convert from the constant folding code | |
980 | on subtrees of already build trees after it has ripped them apart. | |
981 | ||
982 | Also, if we ever support range variables, we'll probably also have to | |
983 | do a little bit more work. */ | |
d81e00a4 | 984 | |
985 | tree | |
986 | convert (type, expr) | |
987 | tree type, expr; | |
988 | { | |
c4a8ac95 | 989 | tree intype; |
990 | ||
991 | if (type == error_mark_node || expr == error_mark_node) | |
992 | return error_mark_node; | |
993 | ||
c4a8ac95 | 994 | intype = TREE_TYPE (expr); |
995 | ||
6686e84d | 996 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
c4a8ac95 | 997 | { |
998 | if (TREE_READONLY_DECL_P (expr)) | |
999 | expr = decl_constant_value (expr); | |
1000 | return fold (build1 (NOP_EXPR, type, expr)); | |
1001 | } | |
1002 | ||
1003 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
1004 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); | |
d81e00a4 | 1005 | } |
1006 | ||
c4a8ac95 | 1007 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 1008 | are not normally allowed due to access restrictions |
1009 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 1010 | |
471086d6 | 1011 | tree |
a74e8896 | 1012 | convert_force (type, expr, convtype) |
471086d6 | 1013 | tree type; |
1014 | tree expr; | |
a74e8896 | 1015 | int convtype; |
471086d6 | 1016 | { |
1017 | register tree e = expr; | |
1018 | register enum tree_code code = TREE_CODE (type); | |
1019 | ||
1020 | if (code == REFERENCE_TYPE) | |
d81e00a4 | 1021 | return fold (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, |
1022 | NULL_TREE)); | |
471086d6 | 1023 | else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) |
1024 | e = convert_from_reference (e); | |
1025 | ||
1026 | if (code == POINTER_TYPE) | |
1027 | return fold (convert_to_pointer_force (type, e)); | |
1028 | ||
ac9386a0 | 1029 | /* From typeck.c convert_for_assignment */ |
471086d6 | 1030 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
1031 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
1032 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 1033 | || integer_zerop (e) |
1034 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1035 | && TYPE_PTRMEMFUNC_P (type)) |
1036 | { | |
96624a9e | 1037 | /* compatible pointer to member functions. */ |
ac9386a0 | 1038 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1); |
471086d6 | 1039 | } |
a74e8896 | 1040 | |
c4a8ac95 | 1041 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
471086d6 | 1042 | } |
1043 | ||
471086d6 | 1044 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1045 | exists, return the attempted conversion. This may | |
1046 | return ERROR_MARK_NODE if the conversion is not | |
1047 | allowed (references private members, etc). | |
1048 | If no conversion exists, NULL_TREE is returned. | |
1049 | ||
1050 | If (FOR_SURE & 1) is non-zero, then we allow this type conversion | |
1051 | to take place immediately. Otherwise, we build a SAVE_EXPR | |
ce28ee2e | 1052 | which can be evaluated if the results are ever needed. |
1053 | ||
1054 | Changes to this functions should be mirrored in user_harshness. | |
1055 | ||
1056 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit | |
1057 | object parameter, or by the second standard conversion sequence if | |
1058 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1059 | (jason 8/9/95) */ | |
471086d6 | 1060 | |
471086d6 | 1061 | tree |
1c16607c | 1062 | build_type_conversion (xtype, expr, for_sure) |
471086d6 | 1063 | tree xtype, expr; |
1064 | int for_sure; | |
1065 | { | |
1066 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1067 | into the required type. */ |
0a4be248 | 1068 | return build_user_type_conversion |
1069 | (xtype, expr, for_sure ? LOOKUP_NORMAL : 0); | |
471086d6 | 1070 | } |
1071 | ||
1e66592c | 1072 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1073 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
1074 | which indicates which types are suitable. If COMPLAIN is 1, complain | |
1075 | about ambiguity; otherwise, the caller will deal with it. */ | |
471086d6 | 1076 | |
1e66592c | 1077 | tree |
1078 | build_expr_type_conversion (desires, expr, complain) | |
1079 | int desires; | |
1080 | tree expr; | |
1081 | int complain; | |
471086d6 | 1082 | { |
1e66592c | 1083 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1084 | tree conv = NULL_TREE; |
bdd152ce | 1085 | tree winner = NULL_TREE; |
471086d6 | 1086 | |
954885ed | 1087 | if (expr == null_node |
1088 | && (desires & WANT_INT) | |
1089 | && !(desires & WANT_NULL)) | |
905d4035 | 1090 | cp_warning ("converting NULL to non-pointer type"); |
954885ed | 1091 | |
42b9ec6a | 1092 | if (TREE_CODE (expr) == OFFSET_REF) |
ce28ee2e | 1093 | expr = resolve_offset_ref (expr); |
1094 | expr = convert_from_reference (expr); | |
1095 | basetype = TREE_TYPE (expr); | |
471086d6 | 1096 | |
3d411d73 | 1097 | if (basetype == error_mark_node) |
1098 | return error_mark_node; | |
1099 | ||
bdd152ce | 1100 | if (! IS_AGGR_TYPE (basetype)) |
1101 | switch (TREE_CODE (basetype)) | |
1102 | { | |
1103 | case INTEGER_TYPE: | |
954885ed | 1104 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1105 | return expr; |
1106 | /* else fall through... */ | |
1107 | ||
1108 | case BOOLEAN_TYPE: | |
1109 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1110 | case ENUMERAL_TYPE: | |
1111 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1112 | case REAL_TYPE: | |
1113 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1114 | case POINTER_TYPE: | |
1115 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
985e9ee0 | 1116 | |
bdd152ce | 1117 | case FUNCTION_TYPE: |
1118 | case ARRAY_TYPE: | |
1119 | return (desires & WANT_POINTER) ? default_conversion (expr) | |
1120 | : NULL_TREE; | |
1121 | default: | |
1122 | return NULL_TREE; | |
1123 | } | |
1124 | ||
1125 | /* The code for conversions from class type is currently only used for | |
1126 | delete expressions. Other expressions are handled by build_new_op. */ | |
1127 | ||
1128 | if (! TYPE_HAS_CONVERSION (basetype)) | |
1129 | return NULL_TREE; | |
1130 | ||
1131 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) | |
1132 | { | |
1133 | int win = 0; | |
1134 | tree candidate; | |
1135 | tree cand = TREE_VALUE (conv); | |
1136 | ||
1137 | if (winner && winner == cand) | |
1138 | continue; | |
1139 | ||
1140 | candidate = TREE_TYPE (TREE_TYPE (cand)); | |
1141 | if (TREE_CODE (candidate) == REFERENCE_TYPE) | |
1142 | candidate = TREE_TYPE (candidate); | |
1143 | ||
1144 | switch (TREE_CODE (candidate)) | |
1145 | { | |
1146 | case BOOLEAN_TYPE: | |
1147 | case INTEGER_TYPE: | |
1148 | win = (desires & WANT_INT); break; | |
1149 | case ENUMERAL_TYPE: | |
1150 | win = (desires & WANT_ENUM); break; | |
1151 | case REAL_TYPE: | |
1152 | win = (desires & WANT_FLOAT); break; | |
1153 | case POINTER_TYPE: | |
1154 | win = (desires & WANT_POINTER); break; | |
1155 | ||
1156 | default: | |
1157 | break; | |
1158 | } | |
1159 | ||
1160 | if (win) | |
1161 | { | |
1162 | if (winner) | |
1163 | { | |
1164 | if (complain) | |
1165 | { | |
905d4035 | 1166 | cp_error ("ambiguous default type conversion from `%T'", |
bdd152ce | 1167 | basetype); |
905d4035 | 1168 | cp_error (" candidate conversions include `%D' and `%D'", |
bdd152ce | 1169 | winner, cand); |
1170 | } | |
1171 | return error_mark_node; | |
1172 | } | |
1173 | else | |
1174 | winner = cand; | |
1175 | } | |
1176 | } | |
1e66592c | 1177 | |
bdd152ce | 1178 | if (winner) |
1179 | { | |
1180 | tree type = TREE_TYPE (TREE_TYPE (winner)); | |
1181 | if (TREE_CODE (type) == REFERENCE_TYPE) | |
1182 | type = TREE_TYPE (type); | |
1183 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL); | |
471086d6 | 1184 | } |
1e66592c | 1185 | |
985e9ee0 | 1186 | return NULL_TREE; |
471086d6 | 1187 | } |
bc3887cf | 1188 | |
96624a9e | 1189 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1190 | ||
bc3887cf | 1191 | tree |
1192 | type_promotes_to (type) | |
1193 | tree type; | |
1194 | { | |
3e04bd45 | 1195 | int type_quals; |
ce28ee2e | 1196 | |
1197 | if (type == error_mark_node) | |
1198 | return error_mark_node; | |
1199 | ||
3e04bd45 | 1200 | type_quals = CP_TYPE_QUALS (type); |
bc3887cf | 1201 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1202 | |
1203 | /* bool always promotes to int (not unsigned), even if it's the same | |
1204 | size. */ | |
028ea8b4 | 1205 | if (type == boolean_type_node) |
bb0726a1 | 1206 | type = integer_type_node; |
1207 | ||
1208 | /* Normally convert enums to int, but convert wide enums to something | |
1209 | wider. */ | |
1210 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
1211 | || type == wchar_type_node) | |
6c9497b1 | 1212 | { |
1213 | int precision = MAX (TYPE_PRECISION (type), | |
1214 | TYPE_PRECISION (integer_type_node)); | |
1215 | tree totype = type_for_size (precision, 0); | |
1216 | if (TREE_UNSIGNED (type) | |
1217 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) | |
1218 | type = type_for_size (precision, 1); | |
1219 | else | |
1220 | type = totype; | |
1221 | } | |
bc3887cf | 1222 | else if (C_PROMOTING_INTEGER_TYPE_P (type)) |
1223 | { | |
d0acef9e | 1224 | /* Retain unsignedness if really not getting bigger. */ |
bc3887cf | 1225 | if (TREE_UNSIGNED (type) |
d0acef9e | 1226 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1227 | type = unsigned_type_node; |
1228 | else | |
1229 | type = integer_type_node; | |
1230 | } | |
1231 | else if (type == float_type_node) | |
1232 | type = double_type_node; | |
1233 | ||
3e04bd45 | 1234 | return cp_build_qualified_type (type, type_quals); |
bc3887cf | 1235 | } |
668ae905 | 1236 | |
668ae905 | 1237 | /* The routines below this point are carefully written to conform to |
1238 | the standard. They use the same terminology, and follow the rules | |
1239 | closely. Although they are used only in pt.c at the moment, they | |
1240 | should presumably be used everywhere in the future. */ | |
1241 | ||
1146f179 | 1242 | /* Attempt to perform qualification conversions on EXPR to convert it |
1243 | to TYPE. Return the resulting expression, or error_mark_node if | |
1244 | the conversion was impossible. */ | |
1245 | ||
668ae905 | 1246 | tree |
1247 | perform_qualification_conversions (type, expr) | |
1248 | tree type; | |
1249 | tree expr; | |
1250 | { | |
213d2076 | 1251 | if (TREE_CODE (type) == POINTER_TYPE |
1252 | && TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE | |
1253 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (TREE_TYPE (expr)))) | |
1146f179 | 1254 | return build1 (NOP_EXPR, type, expr); |
1255 | else | |
1256 | return error_mark_node; | |
668ae905 | 1257 | } |