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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, |
e63bd8ae | 3 | 1999, 2000, 2001, 2002 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" |
805e22b2 | 31 | #include "coretypes.h" |
32 | #include "tm.h" | |
471086d6 | 33 | #include "tree.h" |
34 | #include "flags.h" | |
35 | #include "cp-tree.h" | |
471086d6 | 36 | #include "convert.h" |
f0eaeecd | 37 | #include "toplev.h" |
2e8226f7 | 38 | #include "decl.h" |
96624a9e | 39 | |
045ed8f8 | 40 | static tree cp_convert_to_pointer PARAMS ((tree, tree, int)); |
24054144 | 41 | static tree convert_to_pointer_force PARAMS ((tree, tree)); |
ca106ab1 | 42 | static tree build_up_reference PARAMS ((tree, tree, int, tree)); |
519ba62c | 43 | static void warn_ref_binding PARAMS ((tree, tree, tree)); |
71ccdfff | 44 | |
471086d6 | 45 | /* Change of width--truncation and extension of integers or reals-- |
46 | is represented with NOP_EXPR. Proper functioning of many things | |
47 | assumes that no other conversions can be NOP_EXPRs. | |
48 | ||
49 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
50 | Converting integer to real uses FLOAT_EXPR | |
51 | and real to integer uses FIX_TRUNC_EXPR. | |
52 | ||
53 | Here is a list of all the functions that assume that widening and | |
54 | narrowing is always done with a NOP_EXPR: | |
55 | In convert.c, convert_to_integer. | |
56 | In c-typeck.c, build_binary_op_nodefault (boolean ops), | |
aff9e656 | 57 | and c_common_truthvalue_conversion. |
471086d6 | 58 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
59 | In fold-const.c: fold. | |
60 | In tree.c: get_narrower and get_unwidened. | |
61 | ||
62 | C++: in multiple-inheritance, converting between pointers may involve | |
63 | adjusting them by a delta stored within the class definition. */ | |
64 | \f | |
65 | /* Subroutines of `convert'. */ | |
66 | ||
471086d6 | 67 | /* if converting pointer to pointer |
68 | if dealing with classes, check for derived->base or vice versa | |
69 | else if dealing with method pointers, delegate | |
70 | else convert blindly | |
71 | else if converting class, pass off to build_type_conversion | |
045ed8f8 | 72 | else try C-style pointer conversion. If FORCE is true then allow |
73 | conversions via virtual bases (these are permitted by reinterpret_cast, | |
74 | but not static_cast). */ | |
96624a9e | 75 | |
471086d6 | 76 | static tree |
045ed8f8 | 77 | cp_convert_to_pointer (type, expr, force) |
471086d6 | 78 | tree type, expr; |
045ed8f8 | 79 | int force; |
471086d6 | 80 | { |
81 | register tree intype = TREE_TYPE (expr); | |
74002e1d | 82 | register enum tree_code form; |
f82eeb87 | 83 | tree rval; |
74002e1d | 84 | |
96624a9e | 85 | if (IS_AGGR_TYPE (intype)) |
86 | { | |
96624a9e | 87 | intype = complete_type (intype); |
4b72716d | 88 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 89 | { |
cf103c6c | 90 | error ("can't convert from incomplete type `%T' to `%T'", |
96624a9e | 91 | intype, type); |
92 | return error_mark_node; | |
93 | } | |
94 | ||
1c16607c | 95 | rval = build_type_conversion (type, expr, 1); |
96624a9e | 96 | if (rval) |
97 | { | |
98 | if (rval == error_mark_node) | |
cf103c6c | 99 | error ("conversion of `%E' from `%T' to `%T' is ambiguous", |
96624a9e | 100 | expr, intype, type); |
101 | return rval; | |
102 | } | |
103 | } | |
104 | ||
860740a7 | 105 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 106 | if (TREE_CODE (type) == POINTER_TYPE |
107 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
e3cfe3ce | 108 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 109 | { |
110 | /* Allow an implicit this pointer for pointer to member | |
111 | functions. */ | |
860740a7 | 112 | if (TYPE_PTRMEMFUNC_P (intype)) |
38281c46 | 113 | { |
860740a7 | 114 | tree fntype = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (intype)); |
2917b86f | 115 | tree decl = maybe_dummy_object (TYPE_METHOD_BASETYPE (fntype), 0); |
38281c46 | 116 | expr = build (OFFSET_REF, fntype, decl, expr); |
117 | } | |
118 | ||
119 | if (TREE_CODE (expr) == OFFSET_REF | |
120 | && TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
121 | expr = resolve_offset_ref (expr); | |
122 | if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
123 | expr = build_addr_func (expr); | |
124 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) | |
125 | { | |
126 | if (TREE_CODE (TREE_TYPE (TREE_TYPE (expr))) == METHOD_TYPE) | |
127 | if (pedantic || warn_pmf2ptr) | |
cf103c6c | 128 | pedwarn ("converting from `%T' to `%T'", TREE_TYPE (expr), |
38281c46 | 129 | type); |
130 | return build1 (NOP_EXPR, type, expr); | |
131 | } | |
132 | intype = TREE_TYPE (expr); | |
133 | } | |
134 | ||
311e42bc | 135 | if (expr == error_mark_node) |
136 | return error_mark_node; | |
137 | ||
74002e1d | 138 | form = TREE_CODE (intype); |
139 | ||
2b77484d | 140 | if (POINTER_TYPE_P (intype)) |
471086d6 | 141 | { |
142 | intype = TYPE_MAIN_VARIANT (intype); | |
143 | ||
144 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 145 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 146 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
bccffb3a | 147 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
148 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
4a2680fc | 149 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
471086d6 | 150 | { |
151 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 152 | tree binfo; |
153 | ||
c0af329c | 154 | /* Try derived to base conversion. */ |
4a2680fc | 155 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), |
156 | ba_check, NULL); | |
157 | if (!binfo) | |
471086d6 | 158 | { |
c0af329c | 159 | /* Try base to derived conversion. */ |
4a2680fc | 160 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
161 | ba_check, NULL); | |
471086d6 | 162 | code = MINUS_EXPR; |
163 | } | |
4a2680fc | 164 | if (binfo == error_mark_node) |
165 | return error_mark_node; | |
471086d6 | 166 | if (binfo) |
167 | { | |
4a2680fc | 168 | expr = build_base_path (code, expr, binfo, 0); |
c0af329c | 169 | /* Add any qualifier conversions. */ |
4a2680fc | 170 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
171 | TREE_TYPE (type))) | |
471086d6 | 172 | { |
4a2680fc | 173 | expr = build1 (NOP_EXPR, type, expr); |
174 | TREE_CONSTANT (expr) = | |
175 | TREE_CONSTANT (TREE_OPERAND (expr, 0)); | |
471086d6 | 176 | } |
4a2680fc | 177 | return expr; |
471086d6 | 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; | |
4a2680fc | 186 | enum tree_code code = PLUS_EXPR; |
187 | base_kind bk; | |
a17aefa2 | 188 | |
189 | b1 = TYPE_OFFSET_BASETYPE (TREE_TYPE (type)); | |
190 | b2 = TYPE_OFFSET_BASETYPE (TREE_TYPE (intype)); | |
4a2680fc | 191 | binfo = lookup_base (b1, b2, ba_check, &bk); |
192 | if (!binfo) | |
fc9fc8d8 | 193 | { |
4a2680fc | 194 | binfo = lookup_base (b2, b1, ba_check, &bk); |
fc9fc8d8 | 195 | code = MINUS_EXPR; |
196 | } | |
bea7d742 | 197 | if (binfo == error_mark_node) |
198 | return error_mark_node; | |
a17aefa2 | 199 | |
4a2680fc | 200 | if (bk == bk_via_virtual) |
7045d67a | 201 | { |
045ed8f8 | 202 | if (force) |
cf103c6c | 203 | warning ("pointer to member cast from `%T' to `%T' is via virtual base", |
4a2680fc | 204 | TREE_TYPE (intype), TREE_TYPE (type)); |
045ed8f8 | 205 | else |
206 | { | |
cf103c6c | 207 | error ("pointer to member cast from `%T' to `%T' is via virtual base", |
4a2680fc | 208 | TREE_TYPE (intype), TREE_TYPE (type)); |
045ed8f8 | 209 | return error_mark_node; |
210 | } | |
1bbb5947 | 211 | /* This is a reinterpret cast, whose result is unspecified. |
212 | We choose to do nothing. */ | |
213 | return build1 (NOP_EXPR, type, expr); | |
7045d67a | 214 | } |
215 | ||
a17aefa2 | 216 | if (TREE_CODE (expr) == PTRMEM_CST) |
217 | expr = cplus_expand_constant (expr); | |
218 | ||
1bbb5947 | 219 | if (binfo) |
220 | expr = size_binop (code, convert (sizetype, expr), | |
902de8ed | 221 | BINFO_OFFSET (binfo)); |
bea7d742 | 222 | } |
2b77484d | 223 | else if (TYPE_PTRMEMFUNC_P (type)) |
ce28ee2e | 224 | { |
cf103c6c | 225 | error ("cannot convert `%E' from type `%T' to type `%T'", |
ce28ee2e | 226 | expr, intype, type); |
227 | return error_mark_node; | |
228 | } | |
229 | ||
f82eeb87 | 230 | rval = build1 (NOP_EXPR, type, expr); |
231 | TREE_CONSTANT (rval) = TREE_CONSTANT (expr); | |
232 | return rval; | |
471086d6 | 233 | } |
2b77484d | 234 | else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)) |
7045d67a | 235 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
2b77484d | 236 | else if (TYPE_PTRMEMFUNC_P (intype)) |
237 | { | |
cf103c6c | 238 | error ("cannot convert `%E' from type `%T' to type `%T'", |
2b77484d | 239 | expr, intype, type); |
240 | return error_mark_node; | |
241 | } | |
471086d6 | 242 | |
243 | my_friendly_assert (form != OFFSET_TYPE, 186); | |
244 | ||
471086d6 | 245 | if (integer_zerop (expr)) |
246 | { | |
2b77484d | 247 | if (TYPE_PTRMEMFUNC_P (type)) |
f05d5d03 | 248 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
ad63a0fc | 249 | |
606b494c | 250 | if (TYPE_PTRMEM_P (type)) |
5ad590ad | 251 | /* A NULL pointer-to-member is represented by -1, not by |
252 | zero. */ | |
ad63a0fc | 253 | expr = build_int_2 (-1, -1); |
254 | else | |
255 | expr = build_int_2 (0, 0); | |
471086d6 | 256 | TREE_TYPE (expr) = type; |
8f5d16f2 | 257 | /* Fix up the representation of -1 if appropriate. */ |
258 | force_fit_type (expr, 0); | |
471086d6 | 259 | return expr; |
260 | } | |
de1f960a | 261 | else if ((TYPE_PTRMEM_P (type) || TYPE_PTRMEMFUNC_P (type)) |
262 | && INTEGRAL_CODE_P (form)) | |
263 | { | |
264 | error ("invalid conversion from '%T' to '%T'", intype, type); | |
265 | return error_mark_node; | |
266 | } | |
471086d6 | 267 | |
bb0726a1 | 268 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 269 | { |
c5aa1e92 | 270 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 271 | return build1 (CONVERT_EXPR, type, expr); |
771d21fa | 272 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr); |
471086d6 | 273 | /* Modes may be different but sizes should be the same. */ |
274 | if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
275 | != GET_MODE_SIZE (TYPE_MODE (type))) | |
276 | /* There is supposed to be some integral type | |
277 | that is the same width as a pointer. */ | |
278 | abort (); | |
279 | return convert_to_pointer (type, expr); | |
280 | } | |
281 | ||
cc4d0855 | 282 | if (type_unknown_p (expr)) |
4b471722 | 283 | return instantiate_type (type, expr, tf_error | tf_warning); |
cc4d0855 | 284 | |
cf103c6c | 285 | error ("cannot convert `%E' from type `%T' to type `%T'", |
471086d6 | 286 | expr, intype, type); |
287 | return error_mark_node; | |
288 | } | |
289 | ||
290 | /* Like convert, except permit conversions to take place which | |
291 | are not normally allowed due to access restrictions | |
292 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 293 | |
471086d6 | 294 | static tree |
295 | convert_to_pointer_force (type, expr) | |
296 | tree type, expr; | |
297 | { | |
298 | register tree intype = TREE_TYPE (expr); | |
299 | register enum tree_code form = TREE_CODE (intype); | |
300 | ||
471086d6 | 301 | if (form == POINTER_TYPE) |
302 | { | |
303 | intype = TYPE_MAIN_VARIANT (intype); | |
304 | ||
305 | if (TYPE_MAIN_VARIANT (type) != intype | |
306 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
bccffb3a | 307 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
308 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
471086d6 | 309 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
310 | { | |
311 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 312 | tree binfo; |
313 | ||
314 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
315 | ba_ignore, NULL); | |
316 | if (!binfo) | |
471086d6 | 317 | { |
4a2680fc | 318 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
319 | ba_ignore, NULL); | |
320 | code = MINUS_EXPR; | |
471086d6 | 321 | } |
4a2680fc | 322 | if (binfo == error_mark_node) |
323 | return error_mark_node; | |
324 | if (binfo) | |
471086d6 | 325 | { |
4a2680fc | 326 | expr = build_base_path (code, expr, binfo, 0); |
de922179 | 327 | if (expr == error_mark_node) |
328 | return error_mark_node; | |
c0af329c | 329 | /* Add any qualifier conversions. */ |
4a2680fc | 330 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
331 | TREE_TYPE (type))) | |
332 | { | |
333 | expr = build1 (NOP_EXPR, type, expr); | |
334 | TREE_CONSTANT (expr) = | |
335 | TREE_CONSTANT (TREE_OPERAND (expr, 0)); | |
336 | } | |
337 | return expr; | |
471086d6 | 338 | } |
4a2680fc | 339 | |
471086d6 | 340 | } |
471086d6 | 341 | } |
342 | ||
045ed8f8 | 343 | return cp_convert_to_pointer (type, expr, 1); |
471086d6 | 344 | } |
345 | ||
346 | /* We are passing something to a function which requires a reference. | |
347 | The type we are interested in is in TYPE. The initial | |
348 | value we have to begin with is in ARG. | |
349 | ||
350 | FLAGS controls how we manage access checking. | |
ca106ab1 | 351 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
352 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 353 | |
471086d6 | 354 | static tree |
ca106ab1 | 355 | build_up_reference (type, arg, flags, decl) |
356 | tree type, arg, decl; | |
6a44e72e | 357 | int flags; |
471086d6 | 358 | { |
c76251c1 | 359 | tree rval; |
0543e7a9 | 360 | tree argtype = TREE_TYPE (arg); |
471086d6 | 361 | tree target_type = TREE_TYPE (type); |
c23ebfdd | 362 | tree stmt_expr = NULL_TREE; |
471086d6 | 363 | |
364 | my_friendly_assert (TREE_CODE (type) == REFERENCE_TYPE, 187); | |
471086d6 | 365 | |
c76251c1 | 366 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 367 | { |
ca106ab1 | 368 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
369 | here because it needs to live as long as DECL. */ | |
c76251c1 | 370 | tree targ = arg; |
ca106ab1 | 371 | |
372 | arg = build_decl (VAR_DECL, NULL_TREE, argtype); | |
373 | DECL_ARTIFICIAL (arg) = 1; | |
374 | TREE_USED (arg) = 1; | |
375 | TREE_STATIC (arg) = TREE_STATIC (decl); | |
376 | ||
377 | if (TREE_STATIC (decl)) | |
378 | { | |
379 | /* Namespace-scope or local static; give it a mangled name. */ | |
380 | tree name = mangle_ref_init_variable (decl); | |
381 | DECL_NAME (arg) = name; | |
382 | SET_DECL_ASSEMBLER_NAME (arg, name); | |
383 | arg = pushdecl_top_level (arg); | |
384 | } | |
471086d6 | 385 | else |
386 | { | |
243adba6 | 387 | /* Automatic; make sure we handle the cleanup properly. */ |
614cc70d | 388 | maybe_push_cleanup_level (argtype); |
ca106ab1 | 389 | arg = pushdecl (arg); |
1ad432f2 | 390 | } |
c23ebfdd | 391 | |
392 | /* Process the initializer for the declaration. */ | |
38281c46 | 393 | DECL_INITIAL (arg) = targ; |
ce23987e | 394 | cp_finish_decl (arg, targ, NULL_TREE, |
011310f7 | 395 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 396 | } |
c76251c1 | 397 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
1d8e4310 | 398 | return get_target_expr (arg); |
1ad432f2 | 399 | |
ca106ab1 | 400 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 401 | address, transform all occurrences of the register, into a memory |
402 | reference we could win better. */ | |
c76251c1 | 403 | rval = build_unary_op (ADDR_EXPR, arg, 1); |
15e55420 | 404 | if (rval == error_mark_node) |
405 | return error_mark_node; | |
406 | ||
6686e84d | 407 | if ((flags & LOOKUP_PROTECT) |
408 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
409 | && IS_AGGR_TYPE (argtype) | |
410 | && IS_AGGR_TYPE (target_type)) | |
411 | { | |
7e6960e0 | 412 | /* We go through lookup_base for the access control. */ |
4a2680fc | 413 | tree binfo = lookup_base (argtype, target_type, ba_check, NULL); |
6686e84d | 414 | if (binfo == error_mark_node) |
415 | return error_mark_node; | |
416 | if (binfo == NULL_TREE) | |
417 | return error_not_base_type (target_type, argtype); | |
4a2680fc | 418 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1); |
6686e84d | 419 | } |
c76251c1 | 420 | else |
421 | rval | |
422 | = convert_to_pointer_force (build_pointer_type (target_type), rval); | |
6686e84d | 423 | rval = build1 (NOP_EXPR, type, rval); |
c76251c1 | 424 | TREE_CONSTANT (rval) = TREE_CONSTANT (TREE_OPERAND (rval, 0)); |
c23ebfdd | 425 | |
426 | /* If we created and initialized a new temporary variable, add the | |
427 | representation of that initialization to the RVAL. */ | |
428 | if (stmt_expr) | |
429 | rval = build (COMPOUND_EXPR, TREE_TYPE (rval), stmt_expr, rval); | |
430 | ||
431 | /* And return the result. */ | |
471086d6 | 432 | return rval; |
433 | } | |
434 | ||
519ba62c | 435 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
436 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
437 | for diagnostics. | |
438 | ||
439 | [dcl.init.ref] says that if an rvalue is used to | |
440 | initialize a reference, then the reference must be to a | |
441 | non-volatile const type. */ | |
442 | ||
443 | static void | |
444 | warn_ref_binding (reftype, intype, decl) | |
445 | tree reftype, intype, decl; | |
446 | { | |
447 | tree ttl = TREE_TYPE (reftype); | |
448 | ||
449 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) | |
450 | { | |
451 | const char *msg; | |
452 | ||
453 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
454 | msg = "initialization of volatile reference type `%#T' from rvalue of type `%T'"; | |
455 | else if (CP_TYPE_VOLATILE_P (ttl)) | |
456 | msg = "conversion to volatile reference type `%#T' from rvalue of type `%T'"; | |
457 | else if (decl) | |
458 | msg = "initialization of non-const reference type `%#T' from rvalue of type `%T'"; | |
459 | else | |
460 | msg = "conversion to non-const reference type `%#T' from rvalue of type `%T'"; | |
461 | ||
cf103c6c | 462 | pedwarn (msg, reftype, intype); |
519ba62c | 463 | } |
464 | } | |
465 | ||
471086d6 | 466 | /* For C++: Only need to do one-level references, but cannot |
467 | get tripped up on signed/unsigned differences. | |
468 | ||
d81e00a4 | 469 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
470 | initialized. It can be error_mark_node if we don't know the _DECL but | |
471 | we know it's an initialization. */ | |
471086d6 | 472 | |
471086d6 | 473 | tree |
d81e00a4 | 474 | convert_to_reference (reftype, expr, convtype, flags, decl) |
471086d6 | 475 | tree reftype, expr; |
d81e00a4 | 476 | int convtype, flags; |
477 | tree decl; | |
471086d6 | 478 | { |
479 | register tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); | |
d32df6a6 | 480 | register tree intype; |
471086d6 | 481 | tree rval = NULL_TREE; |
1a3f833b | 482 | tree rval_as_conversion = NULL_TREE; |
483 | int i; | |
484 | ||
d32df6a6 | 485 | if (TREE_CODE (type) == FUNCTION_TYPE |
486 | && TREE_TYPE (expr) == unknown_type_node) | |
cc4d0855 | 487 | { |
3effa7a7 | 488 | expr = instantiate_type (type, expr, |
ffe5bd74 | 489 | (flags & LOOKUP_COMPLAIN) |
4b471722 | 490 | ? tf_error | tf_warning : tf_none); |
3effa7a7 | 491 | if (expr == error_mark_node) |
492 | return error_mark_node; | |
493 | ||
cc4d0855 | 494 | intype = TREE_TYPE (expr); |
495 | } | |
d32df6a6 | 496 | else |
497 | { | |
498 | expr = convert_from_reference (expr); | |
499 | intype = TREE_TYPE (expr); | |
500 | } | |
cc4d0855 | 501 | |
8bc57e28 | 502 | my_friendly_assert (TREE_CODE (intype) != REFERENCE_TYPE, 364); |
471086d6 | 503 | |
471086d6 | 504 | intype = TYPE_MAIN_VARIANT (intype); |
505 | ||
1a3f833b | 506 | i = comp_target_types (type, intype, 0); |
507 | ||
508 | if (i <= 0 && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) | |
509 | && ! (flags & LOOKUP_NO_CONVERSION)) | |
510 | { | |
511 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
512 | ||
0a4be248 | 513 | rval_as_conversion |
1c16607c | 514 | = build_type_conversion (reftype, expr, 1); |
1a3f833b | 515 | |
516 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
517 | && real_lvalue_p (rval_as_conversion)) | |
518 | { | |
519 | expr = rval_as_conversion; | |
520 | rval_as_conversion = NULL_TREE; | |
521 | intype = type; | |
522 | i = 1; | |
523 | } | |
524 | } | |
525 | ||
526 | if (((convtype & CONV_STATIC) && i == -1) | |
527 | || ((convtype & CONV_IMPLICIT) && i == 1)) | |
471086d6 | 528 | { |
471086d6 | 529 | if (flags & LOOKUP_COMPLAIN) |
530 | { | |
bc3887cf | 531 | tree ttl = TREE_TYPE (reftype); |
cb0ba4ec | 532 | tree ttr = lvalue_type (expr); |
471086d6 | 533 | |
519ba62c | 534 | if (! real_lvalue_p (expr)) |
535 | warn_ref_binding (reftype, intype, decl); | |
536 | ||
537 | if (! (convtype & CONV_CONST) | |
3e04bd45 | 538 | && !at_least_as_qualified_p (ttl, ttr)) |
cf103c6c | 539 | pedwarn ("conversion from `%T' to `%T' discards qualifiers", |
caa99b15 | 540 | ttr, reftype); |
0543e7a9 | 541 | } |
542 | ||
ca106ab1 | 543 | return build_up_reference (reftype, expr, flags, decl); |
471086d6 | 544 | } |
c07b1ad1 | 545 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 546 | { |
547 | /* When casting an lvalue to a reference type, just convert into | |
548 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 549 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 550 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 551 | |
3748625f | 552 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
e581f478 | 553 | meant. */ |
1a3f833b | 554 | if (TREE_CODE (intype) == POINTER_TYPE |
daf9ff67 | 555 | && (comptypes (TREE_TYPE (intype), type, |
556 | COMPARE_BASE | COMPARE_RELAXED ))) | |
cf103c6c | 557 | warning ("casting `%T' to `%T' does not dereference pointer", |
e581f478 | 558 | intype, reftype); |
559 | ||
0543e7a9 | 560 | rval = build_unary_op (ADDR_EXPR, expr, 0); |
561 | if (rval != error_mark_node) | |
985e9ee0 | 562 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
563 | rval, 0); | |
0543e7a9 | 564 | if (rval != error_mark_node) |
b0722fac | 565 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 566 | } |
0a4be248 | 567 | else |
860740a7 | 568 | { |
569 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
570 | "converting", 0, 0); | |
a66fe4cb | 571 | if (rval == NULL_TREE || rval == error_mark_node) |
572 | return rval; | |
519ba62c | 573 | warn_ref_binding (reftype, intype, decl); |
ca106ab1 | 574 | rval = build_up_reference (reftype, rval, flags, decl); |
860740a7 | 575 | } |
471086d6 | 576 | |
577 | if (rval) | |
578 | { | |
96624a9e | 579 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 580 | return rval; |
581 | } | |
582 | ||
1a3f833b | 583 | my_friendly_assert (TREE_CODE (intype) != OFFSET_TYPE, 189); |
471086d6 | 584 | |
b248d3f7 | 585 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 586 | error ("cannot convert type `%T' to type `%T'", intype, reftype); |
b248d3f7 | 587 | |
471086d6 | 588 | if (flags & LOOKUP_SPECULATIVELY) |
589 | return NULL_TREE; | |
590 | ||
591 | return error_mark_node; | |
592 | } | |
593 | ||
594 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 595 | way down to its lowest form. */ |
596 | ||
471086d6 | 597 | tree |
598 | convert_from_reference (val) | |
599 | tree val; | |
600 | { | |
601 | tree type = TREE_TYPE (val); | |
602 | ||
603 | if (TREE_CODE (type) == OFFSET_TYPE) | |
604 | type = TREE_TYPE (type); | |
8c5c575d | 605 | if (TREE_CODE (type) == REFERENCE_TYPE) |
4d698345 | 606 | return build_indirect_ref (val, NULL); |
471086d6 | 607 | return val; |
608 | } | |
dbacd3bd | 609 | |
610 | /* Implicitly convert the lvalue EXPR to another lvalue of type TOTYPE, | |
611 | preserving cv-qualification. */ | |
612 | ||
613 | tree | |
614 | convert_lvalue (totype, expr) | |
615 | tree totype, expr; | |
616 | { | |
617 | totype = cp_build_qualified_type (totype, TYPE_QUALS (TREE_TYPE (expr))); | |
618 | totype = build_reference_type (totype); | |
619 | expr = convert_to_reference (totype, expr, CONV_IMPLICIT, LOOKUP_NORMAL, | |
620 | NULL_TREE); | |
621 | return convert_from_reference (expr); | |
622 | } | |
471086d6 | 623 | \f |
c4a8ac95 | 624 | /* C++ conversions, preference to static cast conversions. */ |
625 | ||
626 | tree | |
627 | cp_convert (type, expr) | |
628 | tree type, expr; | |
629 | { | |
630 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); | |
631 | } | |
632 | ||
b248d3f7 | 633 | /* Conversion... |
634 | ||
635 | FLAGS indicates how we should behave. */ | |
636 | ||
471086d6 | 637 | tree |
c4a8ac95 | 638 | ocp_convert (type, expr, convtype, flags) |
471086d6 | 639 | tree type, expr; |
d81e00a4 | 640 | int convtype, flags; |
471086d6 | 641 | { |
642 | register tree e = expr; | |
643 | register enum tree_code code = TREE_CODE (type); | |
644 | ||
b465397d | 645 | if (e == error_mark_node |
646 | || TREE_TYPE (e) == error_mark_node) | |
471086d6 | 647 | return error_mark_node; |
d81e00a4 | 648 | |
5b592939 | 649 | complete_type (type); |
650 | complete_type (TREE_TYPE (expr)); | |
651 | ||
1202e392 | 652 | e = decl_constant_value (e); |
7745052b | 653 | |
2133b374 | 654 | if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP) |
655 | /* Some internal structures (vtable_entry_type, sigtbl_ptr_type) | |
656 | don't go through finish_struct, so they don't have the synthesized | |
657 | constructors. So don't force a temporary. */ | |
658 | && TYPE_HAS_CONSTRUCTOR (type)) | |
1a3f833b | 659 | /* We need a new temporary; don't take this shortcut. */; |
660 | else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) | |
ca23ec64 | 661 | { |
daf9ff67 | 662 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 663 | /* The call to fold will not always remove the NOP_EXPR as |
664 | might be expected, since if one of the types is a typedef; | |
665 | the comparsion in fold is just equality of pointers, not a | |
f699c174 | 666 | call to comptypes. We don't call fold in this case because |
667 | that can result in infinite recursion; fold will call | |
668 | convert, which will call ocp_convert, etc. */ | |
669 | return e; | |
372e0e29 | 670 | /* For complex data types, we need to perform componentwise |
671 | conversion. */ | |
672 | else if (TREE_CODE (type) == COMPLEX_TYPE) | |
673 | return fold (convert_to_complex (type, e)); | |
ca23ec64 | 674 | else |
f699c174 | 675 | return fold (build1 (NOP_EXPR, type, e)); |
ca23ec64 | 676 | } |
677 | ||
d81e00a4 | 678 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 679 | { |
b1a8d4ce | 680 | e = convert_to_void (e, /*implicit=*/NULL); |
aeef2be5 | 681 | return e; |
95b2ac55 | 682 | } |
d81e00a4 | 683 | |
471086d6 | 684 | /* Just convert to the type of the member. */ |
685 | if (code == OFFSET_TYPE) | |
686 | { | |
687 | type = TREE_TYPE (type); | |
688 | code = TREE_CODE (type); | |
689 | } | |
690 | ||
f3ba5c6a | 691 | if (TREE_CODE (e) == OFFSET_REF) |
692 | e = resolve_offset_ref (e); | |
693 | ||
bb0726a1 | 694 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 695 | { |
617abf06 | 696 | tree intype = TREE_TYPE (e); |
02d7f858 | 697 | /* enum = enum, enum = int, enum = float, (enum)pointer are all |
698 | errors. */ | |
723d9ad3 | 699 | if (TREE_CODE (type) == ENUMERAL_TYPE |
02d7f858 | 700 | && ((ARITHMETIC_TYPE_P (intype) && ! (convtype & CONV_STATIC)) |
701 | || (TREE_CODE (intype) == POINTER_TYPE))) | |
471086d6 | 702 | { |
cf103c6c | 703 | pedwarn ("conversion from `%#T' to `%#T'", intype, type); |
471086d6 | 704 | |
705 | if (flag_pedantic_errors) | |
706 | return error_mark_node; | |
707 | } | |
f3ba5c6a | 708 | if (IS_AGGR_TYPE (intype)) |
471086d6 | 709 | { |
710 | tree rval; | |
1c16607c | 711 | rval = build_type_conversion (type, e, 1); |
6495357a | 712 | if (rval) |
713 | return rval; | |
b248d3f7 | 714 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 715 | error ("`%#T' used where a `%T' was expected", intype, type); |
b248d3f7 | 716 | if (flags & LOOKUP_SPECULATIVELY) |
717 | return NULL_TREE; | |
471086d6 | 718 | return error_mark_node; |
719 | } | |
bb0726a1 | 720 | if (code == BOOLEAN_TYPE) |
e4ce2dc4 | 721 | { |
5b592939 | 722 | tree fn = NULL_TREE; |
723 | ||
e4ce2dc4 | 724 | /* Common Ada/Pascal programmer's mistake. We always warn |
725 | about this since it is so bad. */ | |
726 | if (TREE_CODE (expr) == FUNCTION_DECL) | |
5b592939 | 727 | fn = expr; |
728 | else if (TREE_CODE (expr) == ADDR_EXPR | |
729 | && TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL) | |
730 | fn = TREE_OPERAND (expr, 0); | |
1d2ca10c | 731 | if (fn && !DECL_WEAK (fn)) |
cf103c6c | 732 | warning ("the address of `%D', will always be `true'", fn); |
2e0e6579 | 733 | return cp_truthvalue_conversion (e); |
e4ce2dc4 | 734 | } |
471086d6 | 735 | return fold (convert_to_integer (type, e)); |
736 | } | |
74002e1d | 737 | if (code == POINTER_TYPE || code == REFERENCE_TYPE |
738 | || TYPE_PTRMEMFUNC_P (type)) | |
045ed8f8 | 739 | return fold (cp_convert_to_pointer (type, e, 0)); |
684b9d79 | 740 | if (code == VECTOR_TYPE) |
741 | return fold (convert_to_vector (type, e)); | |
c4a8ac95 | 742 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 743 | { |
744 | if (IS_AGGR_TYPE (TREE_TYPE (e))) | |
745 | { | |
746 | tree rval; | |
1c16607c | 747 | rval = build_type_conversion (type, e, 1); |
471086d6 | 748 | if (rval) |
749 | return rval; | |
750 | else | |
b248d3f7 | 751 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 752 | error ("`%#T' used where a floating point value was expected", |
b248d3f7 | 753 | TREE_TYPE (e)); |
471086d6 | 754 | } |
c4a8ac95 | 755 | if (code == REAL_TYPE) |
756 | return fold (convert_to_real (type, e)); | |
757 | else if (code == COMPLEX_TYPE) | |
758 | return fold (convert_to_complex (type, e)); | |
471086d6 | 759 | } |
760 | ||
761 | /* New C++ semantics: since assignment is now based on | |
762 | memberwise copying, if the rhs type is derived from the | |
763 | lhs type, then we may still do a conversion. */ | |
764 | if (IS_AGGR_TYPE_CODE (code)) | |
765 | { | |
766 | tree dtype = TREE_TYPE (e); | |
c25194fd | 767 | tree ctor = NULL_TREE; |
471086d6 | 768 | |
471086d6 | 769 | dtype = TYPE_MAIN_VARIANT (dtype); |
770 | ||
471086d6 | 771 | /* Conversion between aggregate types. New C++ semantics allow |
772 | objects of derived type to be cast to objects of base type. | |
773 | Old semantics only allowed this between pointers. | |
774 | ||
775 | There may be some ambiguity between using a constructor | |
776 | vs. using a type conversion operator when both apply. */ | |
777 | ||
0a4be248 | 778 | ctor = e; |
860740a7 | 779 | |
8c18e707 | 780 | if (abstract_virtuals_error (NULL_TREE, type)) |
781 | return error_mark_node; | |
6cbb4197 | 782 | |
0a4be248 | 783 | if ((flags & LOOKUP_ONLYCONVERTING) |
784 | && ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 785 | /* For copy-initialization, first we create a temp of the proper type |
786 | with a user-defined conversion sequence, then we direct-initialize | |
787 | the target with the temp (see [dcl.init]). */ | |
788 | ctor = build_user_type_conversion (type, ctor, flags); | |
3eb89cd8 | 789 | else |
f70cb9e6 | 790 | ctor = build_special_member_call (NULL_TREE, |
791 | complete_ctor_identifier, | |
792 | build_tree_list (NULL_TREE, ctor), | |
793 | TYPE_BINFO (type), flags); | |
0a4be248 | 794 | if (ctor) |
795 | return build_cplus_new (type, ctor); | |
471086d6 | 796 | } |
797 | ||
b248d3f7 | 798 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 799 | error ("conversion from `%T' to non-scalar type `%T' requested", |
b248d3f7 | 800 | TREE_TYPE (expr), type); |
801 | if (flags & LOOKUP_SPECULATIVELY) | |
802 | return NULL_TREE; | |
471086d6 | 803 | return error_mark_node; |
804 | } | |
805 | ||
b1a8d4ce | 806 | /* When an expression is used in a void context, its value is discarded and |
807 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
808 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
809 | in a void context. The C++ standard does not define what an `access' to an | |
810 | object is, but there is reason to beleive that it is the lvalue to rvalue | |
811 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it | |
812 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
813 | indicates that volatile semantics should be the same between C and C++ | |
814 | where ever possible. C leaves it implementation defined as to what | |
815 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
816 | the volatile object `vp' points to, unless that is an incomplete type. For | |
817 | volatile references we do not do this interpretation, because that would | |
818 | make it impossible to ignore the reference return value from functions. We | |
819 | issue warnings in the confusing cases. | |
820 | ||
821 | IMPLICIT is tells us the context of an implicit void conversion. */ | |
822 | ||
823 | tree | |
824 | convert_to_void (expr, implicit) | |
825 | tree expr; | |
826 | const char *implicit; | |
827 | { | |
3d411d73 | 828 | if (expr == error_mark_node |
829 | || TREE_TYPE (expr) == error_mark_node) | |
830 | return error_mark_node; | |
b1a8d4ce | 831 | if (!TREE_TYPE (expr)) |
832 | return expr; | |
e3cfe3ce | 833 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 834 | return expr; |
835 | switch (TREE_CODE (expr)) | |
836 | { | |
837 | case COND_EXPR: | |
838 | { | |
839 | /* The two parts of a cond expr might be separate lvalues. */ | |
840 | tree op1 = TREE_OPERAND (expr,1); | |
841 | tree op2 = TREE_OPERAND (expr,2); | |
842 | tree new_op1 = convert_to_void (op1, implicit); | |
843 | tree new_op2 = convert_to_void (op2, implicit); | |
844 | ||
1b9a507b | 845 | expr = build (COND_EXPR, TREE_TYPE (new_op1), |
69773da0 | 846 | TREE_OPERAND (expr, 0), new_op1, new_op2); |
b1a8d4ce | 847 | break; |
848 | } | |
849 | ||
850 | case COMPOUND_EXPR: | |
851 | { | |
852 | /* The second part of a compound expr contains the value. */ | |
853 | tree op1 = TREE_OPERAND (expr,1); | |
854 | tree new_op1 = convert_to_void (op1, implicit); | |
855 | ||
856 | if (new_op1 != op1) | |
e907a2e9 | 857 | { |
858 | tree t = build (COMPOUND_EXPR, TREE_TYPE (new_op1), | |
859 | TREE_OPERAND (expr, 0), new_op1); | |
860 | TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (expr); | |
8061c68f | 861 | TREE_NO_UNUSED_WARNING (t) = TREE_NO_UNUSED_WARNING (expr); |
e907a2e9 | 862 | expr = t; |
863 | } | |
864 | ||
b1a8d4ce | 865 | break; |
866 | } | |
867 | ||
868 | case NON_LVALUE_EXPR: | |
869 | case NOP_EXPR: | |
c0af329c | 870 | /* These have already decayed to rvalue. */ |
b1a8d4ce | 871 | break; |
872 | ||
873 | case CALL_EXPR: /* we have a special meaning for volatile void fn() */ | |
874 | break; | |
875 | ||
876 | case INDIRECT_REF: | |
877 | { | |
878 | tree type = TREE_TYPE (expr); | |
879 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
880 | == REFERENCE_TYPE; | |
881 | int is_volatile = TYPE_VOLATILE (type); | |
4b72716d | 882 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 883 | |
884 | if (is_volatile && !is_complete) | |
cf103c6c | 885 | warning ("object of incomplete type `%T' will not be accessed in %s", |
b1a8d4ce | 886 | type, implicit ? implicit : "void context"); |
887 | else if (is_reference && is_volatile) | |
cf103c6c | 888 | warning ("object of type `%T' will not be accessed in %s", |
b1a8d4ce | 889 | TREE_TYPE (TREE_OPERAND (expr, 0)), |
890 | implicit ? implicit : "void context"); | |
891 | if (is_reference || !is_volatile || !is_complete) | |
892 | expr = TREE_OPERAND (expr, 0); | |
893 | ||
894 | break; | |
895 | } | |
896 | ||
897 | case VAR_DECL: | |
898 | { | |
899 | /* External variables might be incomplete. */ | |
900 | tree type = TREE_TYPE (expr); | |
4b72716d | 901 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 902 | |
903 | if (TYPE_VOLATILE (type) && !is_complete) | |
cf103c6c | 904 | warning ("object `%E' of incomplete type `%T' will not be accessed in %s", |
b1a8d4ce | 905 | expr, type, implicit ? implicit : "void context"); |
906 | break; | |
907 | } | |
d9f88785 | 908 | |
909 | case OFFSET_REF: | |
910 | expr = resolve_offset_ref (expr); | |
911 | break; | |
912 | ||
b1a8d4ce | 913 | default:; |
914 | } | |
915 | { | |
916 | tree probe = expr; | |
917 | ||
918 | if (TREE_CODE (probe) == ADDR_EXPR) | |
919 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 920 | if (type_unknown_p (probe)) |
921 | { | |
922 | /* [over.over] enumerates the places where we can take the address | |
923 | of an overloaded function, and this is not one of them. */ | |
cf103c6c | 924 | pedwarn ("%s cannot resolve address of overloaded function", |
2e0e6579 | 925 | implicit ? implicit : "void cast"); |
926 | } | |
927 | else if (implicit && probe == expr && is_overloaded_fn (probe)) | |
b1a8d4ce | 928 | /* Only warn when there is no &. */ |
cf103c6c | 929 | warning ("%s is a reference, not call, to function `%E'", |
2e0e6579 | 930 | implicit, expr); |
b1a8d4ce | 931 | } |
932 | ||
e3cfe3ce | 933 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 934 | { |
935 | /* FIXME: This is where we should check for expressions with no | |
936 | effects. At the moment we do that in both build_x_component_expr | |
937 | and expand_expr_stmt -- inconsistently too. For the moment | |
938 | leave implicit void conversions unadorned so that expand_expr_stmt | |
939 | has a chance of detecting some of the cases. */ | |
940 | if (!implicit) | |
941 | expr = build1 (CONVERT_EXPR, void_type_node, expr); | |
942 | } | |
943 | return expr; | |
944 | } | |
945 | ||
d81e00a4 | 946 | /* Create an expression whose value is that of EXPR, |
947 | converted to type TYPE. The TREE_TYPE of the value | |
948 | is always TYPE. This function implements all reasonable | |
949 | conversions; callers should filter out those that are | |
c4a8ac95 | 950 | not permitted by the language being compiled. |
951 | ||
952 | Most of this routine is from build_reinterpret_cast. | |
953 | ||
954 | The backend cannot call cp_convert (what was convert) because | |
955 | conversions to/from basetypes may involve memory references | |
956 | (vbases) and adding or subtracting small values (multiple | |
957 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 958 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 959 | |
960 | Also, if we ever support range variables, we'll probably also have to | |
961 | do a little bit more work. */ | |
d81e00a4 | 962 | |
963 | tree | |
964 | convert (type, expr) | |
965 | tree type, expr; | |
966 | { | |
c4a8ac95 | 967 | tree intype; |
968 | ||
969 | if (type == error_mark_node || expr == error_mark_node) | |
970 | return error_mark_node; | |
971 | ||
c4a8ac95 | 972 | intype = TREE_TYPE (expr); |
973 | ||
6686e84d | 974 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
c4a8ac95 | 975 | { |
1202e392 | 976 | expr = decl_constant_value (expr); |
c4a8ac95 | 977 | return fold (build1 (NOP_EXPR, type, expr)); |
978 | } | |
979 | ||
980 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
981 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); | |
d81e00a4 | 982 | } |
983 | ||
c4a8ac95 | 984 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 985 | are not normally allowed due to access restrictions |
986 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 987 | |
471086d6 | 988 | tree |
a74e8896 | 989 | convert_force (type, expr, convtype) |
471086d6 | 990 | tree type; |
991 | tree expr; | |
a74e8896 | 992 | int convtype; |
471086d6 | 993 | { |
994 | register tree e = expr; | |
995 | register enum tree_code code = TREE_CODE (type); | |
996 | ||
997 | if (code == REFERENCE_TYPE) | |
d81e00a4 | 998 | return fold (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, |
999 | NULL_TREE)); | |
471086d6 | 1000 | else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) |
1001 | e = convert_from_reference (e); | |
1002 | ||
1003 | if (code == POINTER_TYPE) | |
1004 | return fold (convert_to_pointer_force (type, e)); | |
1005 | ||
ac9386a0 | 1006 | /* From typeck.c convert_for_assignment */ |
471086d6 | 1007 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
1008 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
1009 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 1010 | || integer_zerop (e) |
1011 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1012 | && TYPE_PTRMEMFUNC_P (type)) |
1013 | { | |
96624a9e | 1014 | /* compatible pointer to member functions. */ |
ac9386a0 | 1015 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1); |
471086d6 | 1016 | } |
a74e8896 | 1017 | |
c4a8ac95 | 1018 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
471086d6 | 1019 | } |
1020 | ||
471086d6 | 1021 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1022 | exists, return the attempted conversion. This may | |
1023 | return ERROR_MARK_NODE if the conversion is not | |
1024 | allowed (references private members, etc). | |
1025 | If no conversion exists, NULL_TREE is returned. | |
1026 | ||
3160db1d | 1027 | If (FOR_SURE & 1) is nonzero, then we allow this type conversion |
471086d6 | 1028 | to take place immediately. Otherwise, we build a SAVE_EXPR |
ce28ee2e | 1029 | which can be evaluated if the results are ever needed. |
1030 | ||
1031 | Changes to this functions should be mirrored in user_harshness. | |
1032 | ||
1033 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit | |
1034 | object parameter, or by the second standard conversion sequence if | |
1035 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1036 | (jason 8/9/95) */ | |
471086d6 | 1037 | |
471086d6 | 1038 | tree |
1c16607c | 1039 | build_type_conversion (xtype, expr, for_sure) |
471086d6 | 1040 | tree xtype, expr; |
1041 | int for_sure; | |
1042 | { | |
1043 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1044 | into the required type. */ |
0a4be248 | 1045 | return build_user_type_conversion |
1046 | (xtype, expr, for_sure ? LOOKUP_NORMAL : 0); | |
471086d6 | 1047 | } |
1048 | ||
1e66592c | 1049 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1050 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
1051 | which indicates which types are suitable. If COMPLAIN is 1, complain | |
1052 | about ambiguity; otherwise, the caller will deal with it. */ | |
471086d6 | 1053 | |
1e66592c | 1054 | tree |
1055 | build_expr_type_conversion (desires, expr, complain) | |
1056 | int desires; | |
1057 | tree expr; | |
1058 | int complain; | |
471086d6 | 1059 | { |
1e66592c | 1060 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1061 | tree conv = NULL_TREE; |
bdd152ce | 1062 | tree winner = NULL_TREE; |
471086d6 | 1063 | |
954885ed | 1064 | if (expr == null_node |
1065 | && (desires & WANT_INT) | |
1066 | && !(desires & WANT_NULL)) | |
cf103c6c | 1067 | warning ("converting NULL to non-pointer type"); |
954885ed | 1068 | |
42b9ec6a | 1069 | if (TREE_CODE (expr) == OFFSET_REF) |
ce28ee2e | 1070 | expr = resolve_offset_ref (expr); |
1071 | expr = convert_from_reference (expr); | |
1072 | basetype = TREE_TYPE (expr); | |
471086d6 | 1073 | |
3d411d73 | 1074 | if (basetype == error_mark_node) |
1075 | return error_mark_node; | |
1076 | ||
bdd152ce | 1077 | if (! IS_AGGR_TYPE (basetype)) |
1078 | switch (TREE_CODE (basetype)) | |
1079 | { | |
1080 | case INTEGER_TYPE: | |
954885ed | 1081 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1082 | return expr; |
1083 | /* else fall through... */ | |
1084 | ||
1085 | case BOOLEAN_TYPE: | |
1086 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1087 | case ENUMERAL_TYPE: | |
1088 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1089 | case REAL_TYPE: | |
1090 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1091 | case POINTER_TYPE: | |
1092 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
985e9ee0 | 1093 | |
bdd152ce | 1094 | case FUNCTION_TYPE: |
1095 | case ARRAY_TYPE: | |
1096 | return (desires & WANT_POINTER) ? default_conversion (expr) | |
1097 | : NULL_TREE; | |
1098 | default: | |
1099 | return NULL_TREE; | |
1100 | } | |
1101 | ||
1102 | /* The code for conversions from class type is currently only used for | |
1103 | delete expressions. Other expressions are handled by build_new_op. */ | |
1104 | ||
1105 | if (! TYPE_HAS_CONVERSION (basetype)) | |
1106 | return NULL_TREE; | |
1107 | ||
1108 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) | |
1109 | { | |
1110 | int win = 0; | |
1111 | tree candidate; | |
1112 | tree cand = TREE_VALUE (conv); | |
1113 | ||
1114 | if (winner && winner == cand) | |
1115 | continue; | |
1116 | ||
1117 | candidate = TREE_TYPE (TREE_TYPE (cand)); | |
1118 | if (TREE_CODE (candidate) == REFERENCE_TYPE) | |
1119 | candidate = TREE_TYPE (candidate); | |
1120 | ||
1121 | switch (TREE_CODE (candidate)) | |
1122 | { | |
1123 | case BOOLEAN_TYPE: | |
1124 | case INTEGER_TYPE: | |
1125 | win = (desires & WANT_INT); break; | |
1126 | case ENUMERAL_TYPE: | |
1127 | win = (desires & WANT_ENUM); break; | |
1128 | case REAL_TYPE: | |
1129 | win = (desires & WANT_FLOAT); break; | |
1130 | case POINTER_TYPE: | |
1131 | win = (desires & WANT_POINTER); break; | |
1132 | ||
1133 | default: | |
1134 | break; | |
1135 | } | |
1136 | ||
1137 | if (win) | |
1138 | { | |
1139 | if (winner) | |
1140 | { | |
1141 | if (complain) | |
1142 | { | |
cf103c6c | 1143 | error ("ambiguous default type conversion from `%T'", |
bdd152ce | 1144 | basetype); |
cf103c6c | 1145 | error (" candidate conversions include `%D' and `%D'", |
bdd152ce | 1146 | winner, cand); |
1147 | } | |
1148 | return error_mark_node; | |
1149 | } | |
1150 | else | |
1151 | winner = cand; | |
1152 | } | |
1153 | } | |
1e66592c | 1154 | |
bdd152ce | 1155 | if (winner) |
1156 | { | |
1157 | tree type = TREE_TYPE (TREE_TYPE (winner)); | |
1158 | if (TREE_CODE (type) == REFERENCE_TYPE) | |
1159 | type = TREE_TYPE (type); | |
1160 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL); | |
471086d6 | 1161 | } |
1e66592c | 1162 | |
985e9ee0 | 1163 | return NULL_TREE; |
471086d6 | 1164 | } |
bc3887cf | 1165 | |
96624a9e | 1166 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1167 | ||
bc3887cf | 1168 | tree |
1169 | type_promotes_to (type) | |
1170 | tree type; | |
1171 | { | |
3e04bd45 | 1172 | int type_quals; |
ce28ee2e | 1173 | |
1174 | if (type == error_mark_node) | |
1175 | return error_mark_node; | |
1176 | ||
3119c950 | 1177 | type_quals = cp_type_quals (type); |
bc3887cf | 1178 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1179 | |
1180 | /* bool always promotes to int (not unsigned), even if it's the same | |
1181 | size. */ | |
028ea8b4 | 1182 | if (type == boolean_type_node) |
bb0726a1 | 1183 | type = integer_type_node; |
1184 | ||
1185 | /* Normally convert enums to int, but convert wide enums to something | |
1186 | wider. */ | |
1187 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
1188 | || type == wchar_type_node) | |
6c9497b1 | 1189 | { |
1190 | int precision = MAX (TYPE_PRECISION (type), | |
1191 | TYPE_PRECISION (integer_type_node)); | |
771d21fa | 1192 | tree totype = c_common_type_for_size (precision, 0); |
6c9497b1 | 1193 | if (TREE_UNSIGNED (type) |
1194 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) | |
771d21fa | 1195 | type = c_common_type_for_size (precision, 1); |
6c9497b1 | 1196 | else |
1197 | type = totype; | |
1198 | } | |
d7aeef06 | 1199 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1200 | { |
d0acef9e | 1201 | /* Retain unsignedness if really not getting bigger. */ |
bc3887cf | 1202 | if (TREE_UNSIGNED (type) |
d0acef9e | 1203 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1204 | type = unsigned_type_node; |
1205 | else | |
1206 | type = integer_type_node; | |
1207 | } | |
1208 | else if (type == float_type_node) | |
1209 | type = double_type_node; | |
1210 | ||
3e04bd45 | 1211 | return cp_build_qualified_type (type, type_quals); |
bc3887cf | 1212 | } |
668ae905 | 1213 | |
668ae905 | 1214 | /* The routines below this point are carefully written to conform to |
1215 | the standard. They use the same terminology, and follow the rules | |
1216 | closely. Although they are used only in pt.c at the moment, they | |
1217 | should presumably be used everywhere in the future. */ | |
1218 | ||
1146f179 | 1219 | /* Attempt to perform qualification conversions on EXPR to convert it |
1220 | to TYPE. Return the resulting expression, or error_mark_node if | |
1221 | the conversion was impossible. */ | |
1222 | ||
668ae905 | 1223 | tree |
1224 | perform_qualification_conversions (type, expr) | |
1225 | tree type; | |
1226 | tree expr; | |
1227 | { | |
213d2076 | 1228 | if (TREE_CODE (type) == POINTER_TYPE |
1229 | && TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE | |
1230 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (TREE_TYPE (expr)))) | |
1146f179 | 1231 | return build1 (NOP_EXPR, type, expr); |
1232 | else | |
1233 | return error_mark_node; | |
668ae905 | 1234 | } |