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471086d6 | 1 | /* Language-level data type conversion for GNU C++. |
f1717362 | 2 | Copyright (C) 1987-2016 Free Software Foundation, Inc. |
471086d6 | 3 | Hacked by Michael Tiemann (tiemann@cygnus.com) |
4 | ||
6f0d25a6 | 5 | This file is part of GCC. |
471086d6 | 6 | |
6f0d25a6 | 7 | GCC is free software; you can redistribute it and/or modify |
471086d6 | 8 | it under the terms of the GNU General Public License as published by |
aa139c3f | 9 | the Free Software Foundation; either version 3, or (at your option) |
471086d6 | 10 | any later version. |
11 | ||
6f0d25a6 | 12 | GCC is distributed in the hope that it will be useful, |
471086d6 | 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
aa139c3f | 18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
471086d6 | 20 | |
21 | ||
af86cc06 | 22 | /* This file contains the functions for converting C++ expressions |
471086d6 | 23 | to different data types. The only entry point is `convert'. |
24 | Every language front end must have a `convert' function | |
25 | but what kind of conversions it does will depend on the language. */ | |
26 | ||
27 | #include "config.h" | |
b3ef7553 | 28 | #include "system.h" |
805e22b2 | 29 | #include "coretypes.h" |
4cba6f60 | 30 | #include "target.h" |
4cba6f60 | 31 | #include "cp-tree.h" |
9ed99284 | 32 | #include "stor-layout.h" |
471086d6 | 33 | #include "flags.h" |
ca82e026 | 34 | #include "intl.h" |
471086d6 | 35 | #include "convert.h" |
96624a9e | 36 | |
c4698a21 | 37 | static tree cp_convert_to_pointer (tree, tree, tsubst_flags_t); |
38 | static tree convert_to_pointer_force (tree, tree, tsubst_flags_t); | |
ef9571e5 | 39 | static tree build_type_conversion (tree, tree); |
c4698a21 | 40 | static tree build_up_reference (tree, tree, int, tree, tsubst_flags_t); |
19b271a9 | 41 | static void diagnose_ref_binding (location_t, tree, tree, tree); |
71ccdfff | 42 | |
471086d6 | 43 | /* Change of width--truncation and extension of integers or reals-- |
44 | is represented with NOP_EXPR. Proper functioning of many things | |
45 | assumes that no other conversions can be NOP_EXPRs. | |
46 | ||
47 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
48 | Converting integer to real uses FLOAT_EXPR | |
49 | and real to integer uses FIX_TRUNC_EXPR. | |
50 | ||
51 | Here is a list of all the functions that assume that widening and | |
52 | narrowing is always done with a NOP_EXPR: | |
d2c63826 | 53 | In convert.c, convert_to_integer[_nofold]. |
471086d6 | 54 | In c-typeck.c, build_binary_op_nodefault (boolean ops), |
653e5405 | 55 | and c_common_truthvalue_conversion. |
471086d6 | 56 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
57 | In fold-const.c: fold. | |
58 | In tree.c: get_narrower and get_unwidened. | |
59 | ||
60 | C++: in multiple-inheritance, converting between pointers may involve | |
61 | adjusting them by a delta stored within the class definition. */ | |
62 | \f | |
63 | /* Subroutines of `convert'. */ | |
64 | ||
471086d6 | 65 | /* if converting pointer to pointer |
66 | if dealing with classes, check for derived->base or vice versa | |
67 | else if dealing with method pointers, delegate | |
68 | else convert blindly | |
69 | else if converting class, pass off to build_type_conversion | |
e5ead12a | 70 | else try C-style pointer conversion. */ |
96624a9e | 71 | |
471086d6 | 72 | static tree |
c4698a21 | 73 | cp_convert_to_pointer (tree type, tree expr, tsubst_flags_t complain) |
471086d6 | 74 | { |
cd16867a | 75 | tree intype = TREE_TYPE (expr); |
76 | enum tree_code form; | |
f82eeb87 | 77 | tree rval; |
3df42822 | 78 | location_t loc = EXPR_LOC_OR_LOC (expr, input_location); |
61f69bc9 | 79 | |
8bf328bf | 80 | if (intype == error_mark_node) |
81 | return error_mark_node; | |
74002e1d | 82 | |
95397ff9 | 83 | if (MAYBE_CLASS_TYPE_P (intype)) |
96624a9e | 84 | { |
96624a9e | 85 | intype = complete_type (intype); |
4b72716d | 86 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 87 | { |
c4698a21 | 88 | if (complain & tf_error) |
89 | error_at (loc, "can%'t convert from incomplete type %qT to %qT", | |
90 | intype, type); | |
96624a9e | 91 | return error_mark_node; |
92 | } | |
93 | ||
8999978b | 94 | rval = build_type_conversion (type, expr); |
96624a9e | 95 | if (rval) |
96 | { | |
c4698a21 | 97 | if ((complain & tf_error) |
98 | && rval == error_mark_node) | |
61f69bc9 | 99 | error_at (loc, "conversion of %qE from %qT to %qT is ambiguous", |
100 | expr, intype, type); | |
96624a9e | 101 | return rval; |
102 | } | |
103 | } | |
104 | ||
860740a7 | 105 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
c21c015b | 106 | if (TYPE_PTR_P (type) |
38281c46 | 107 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE |
e3cfe3ce | 108 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 109 | { |
6ab399e8 | 110 | if (TYPE_PTRMEMFUNC_P (intype) |
111 | || TREE_CODE (intype) == METHOD_TYPE) | |
c4698a21 | 112 | return convert_member_func_to_ptr (type, expr, complain); |
c21c015b | 113 | if (TYPE_PTR_P (TREE_TYPE (expr))) |
a63bc44c | 114 | return build_nop (type, expr); |
38281c46 | 115 | intype = TREE_TYPE (expr); |
116 | } | |
117 | ||
311e42bc | 118 | if (expr == error_mark_node) |
119 | return error_mark_node; | |
120 | ||
74002e1d | 121 | form = TREE_CODE (intype); |
122 | ||
2b77484d | 123 | if (POINTER_TYPE_P (intype)) |
471086d6 | 124 | { |
125 | intype = TYPE_MAIN_VARIANT (intype); | |
126 | ||
127 | if (TYPE_MAIN_VARIANT (type) != intype | |
c21c015b | 128 | && TYPE_PTR_P (type) |
471086d6 | 129 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
95397ff9 | 130 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
131 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
4a2680fc | 132 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
471086d6 | 133 | { |
134 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 135 | tree binfo; |
8999978b | 136 | tree intype_class; |
137 | tree type_class; | |
138 | bool same_p; | |
4a2680fc | 139 | |
8999978b | 140 | intype_class = TREE_TYPE (intype); |
141 | type_class = TREE_TYPE (type); | |
142 | ||
9031d10b | 143 | same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class), |
8999978b | 144 | TYPE_MAIN_VARIANT (type_class)); |
145 | binfo = NULL_TREE; | |
c0af329c | 146 | /* Try derived to base conversion. */ |
8999978b | 147 | if (!same_p) |
ae260dcc | 148 | binfo = lookup_base (intype_class, type_class, ba_check, |
149 | NULL, complain); | |
8999978b | 150 | if (!same_p && !binfo) |
471086d6 | 151 | { |
c0af329c | 152 | /* Try base to derived conversion. */ |
ae260dcc | 153 | binfo = lookup_base (type_class, intype_class, ba_check, |
154 | NULL, complain); | |
471086d6 | 155 | code = MINUS_EXPR; |
156 | } | |
4a2680fc | 157 | if (binfo == error_mark_node) |
158 | return error_mark_node; | |
8999978b | 159 | if (binfo || same_p) |
471086d6 | 160 | { |
8999978b | 161 | if (binfo) |
c4698a21 | 162 | expr = build_base_path (code, expr, binfo, 0, complain); |
c0af329c | 163 | /* Add any qualifier conversions. */ |
8999978b | 164 | return build_nop (type, expr); |
471086d6 | 165 | } |
166 | } | |
471086d6 | 167 | |
1bc16cab | 168 | if (TYPE_PTRMEMFUNC_P (type)) |
bea7d742 | 169 | { |
c4698a21 | 170 | if (complain & tf_error) |
171 | error_at (loc, "cannot convert %qE from type %qT to type %qT", | |
172 | expr, intype, type); | |
1bc16cab | 173 | return error_mark_node; |
174 | } | |
a17aefa2 | 175 | |
1bc16cab | 176 | return build_nop (type, expr); |
177 | } | |
05765a91 | 178 | else if ((TYPE_PTRDATAMEM_P (type) && TYPE_PTRDATAMEM_P (intype)) |
e5ead12a | 179 | || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) |
180 | return convert_ptrmem (type, expr, /*allow_inverse_p=*/false, | |
c4698a21 | 181 | /*c_cast_p=*/false, complain); |
2b77484d | 182 | else if (TYPE_PTRMEMFUNC_P (intype)) |
183 | { | |
a63bc44c | 184 | if (!warn_pmf2ptr) |
185 | { | |
186 | if (TREE_CODE (expr) == PTRMEM_CST) | |
c4698a21 | 187 | return cp_convert_to_pointer (type, PTRMEM_CST_MEMBER (expr), |
188 | complain); | |
a63bc44c | 189 | else if (TREE_CODE (expr) == OFFSET_REF) |
190 | { | |
191 | tree object = TREE_OPERAND (expr, 0); | |
192 | return get_member_function_from_ptrfunc (&object, | |
4405c1ad | 193 | TREE_OPERAND (expr, 1), |
c4698a21 | 194 | complain); |
a63bc44c | 195 | } |
196 | } | |
d3f0af4b | 197 | if (complain & tf_error) |
198 | error_at (loc, "cannot convert %qE from type %qT to type %qT", | |
199 | expr, intype, type); | |
2b77484d | 200 | return error_mark_node; |
201 | } | |
471086d6 | 202 | |
ef434176 | 203 | if (null_ptr_cst_p (expr)) |
471086d6 | 204 | { |
2b77484d | 205 | if (TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 206 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
c4698a21 | 207 | /*c_cast_p=*/false, complain); |
ad63a0fc | 208 | |
106c3d67 | 209 | if (complain & tf_warning) |
210 | maybe_warn_zero_as_null_pointer_constant (expr, loc); | |
211 | ||
7ba2f86f | 212 | /* A NULL pointer-to-data-member is represented by -1, not by |
213 | zero. */ | |
214 | tree val = (TYPE_PTRDATAMEM_P (type) | |
215 | ? build_int_cst_type (type, -1) | |
216 | : build_int_cst (type, 0)); | |
217 | ||
218 | return (TREE_SIDE_EFFECTS (expr) | |
219 | ? build2 (COMPOUND_EXPR, type, expr, val) : val); | |
471086d6 | 220 | } |
05765a91 | 221 | else if (TYPE_PTRMEM_P (type) && INTEGRAL_CODE_P (form)) |
de1f960a | 222 | { |
c4698a21 | 223 | if (complain & tf_error) |
224 | error_at (loc, "invalid conversion from %qT to %qT", intype, type); | |
de1f960a | 225 | return error_mark_node; |
226 | } | |
471086d6 | 227 | |
bb0726a1 | 228 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 229 | { |
c5aa1e92 | 230 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 231 | return build1 (CONVERT_EXPR, type, expr); |
c4698a21 | 232 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr, |
233 | complain); | |
092b1d6f | 234 | /* Modes may be different but sizes should be the same. There |
235 | is supposed to be some integral type that is the same width | |
236 | as a pointer. */ | |
237 | gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
238 | == GET_MODE_SIZE (TYPE_MODE (type))); | |
9031d10b | 239 | |
d2c63826 | 240 | return convert_to_pointer_nofold (type, expr); |
471086d6 | 241 | } |
242 | ||
cc4d0855 | 243 | if (type_unknown_p (expr)) |
c4698a21 | 244 | return instantiate_type (type, expr, complain); |
cc4d0855 | 245 | |
c4698a21 | 246 | if (complain & tf_error) |
247 | error_at (loc, "cannot convert %qE from type %qT to type %qT", | |
248 | expr, intype, type); | |
471086d6 | 249 | return error_mark_node; |
250 | } | |
251 | ||
252 | /* Like convert, except permit conversions to take place which | |
253 | are not normally allowed due to access restrictions | |
254 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 255 | |
471086d6 | 256 | static tree |
c4698a21 | 257 | convert_to_pointer_force (tree type, tree expr, tsubst_flags_t complain) |
471086d6 | 258 | { |
cd16867a | 259 | tree intype = TREE_TYPE (expr); |
260 | enum tree_code form = TREE_CODE (intype); | |
9031d10b | 261 | |
471086d6 | 262 | if (form == POINTER_TYPE) |
263 | { | |
264 | intype = TYPE_MAIN_VARIANT (intype); | |
265 | ||
266 | if (TYPE_MAIN_VARIANT (type) != intype | |
267 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
95397ff9 | 268 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
269 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
471086d6 | 270 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
271 | { | |
272 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 273 | tree binfo; |
274 | ||
275 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
ae260dcc | 276 | ba_unique, NULL, complain); |
4a2680fc | 277 | if (!binfo) |
471086d6 | 278 | { |
4a2680fc | 279 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
ae260dcc | 280 | ba_unique, NULL, complain); |
4a2680fc | 281 | code = MINUS_EXPR; |
471086d6 | 282 | } |
4a2680fc | 283 | if (binfo == error_mark_node) |
284 | return error_mark_node; | |
285 | if (binfo) | |
471086d6 | 286 | { |
c4698a21 | 287 | expr = build_base_path (code, expr, binfo, 0, complain); |
653e5405 | 288 | if (expr == error_mark_node) |
289 | return error_mark_node; | |
c0af329c | 290 | /* Add any qualifier conversions. */ |
4a2680fc | 291 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
292 | TREE_TYPE (type))) | |
8999978b | 293 | expr = build_nop (type, expr); |
4a2680fc | 294 | return expr; |
471086d6 | 295 | } |
471086d6 | 296 | } |
471086d6 | 297 | } |
298 | ||
c4698a21 | 299 | return cp_convert_to_pointer (type, expr, complain); |
471086d6 | 300 | } |
301 | ||
302 | /* We are passing something to a function which requires a reference. | |
303 | The type we are interested in is in TYPE. The initial | |
304 | value we have to begin with is in ARG. | |
305 | ||
306 | FLAGS controls how we manage access checking. | |
ca106ab1 | 307 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
308 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 309 | |
471086d6 | 310 | static tree |
c4698a21 | 311 | build_up_reference (tree type, tree arg, int flags, tree decl, |
312 | tsubst_flags_t complain) | |
471086d6 | 313 | { |
c76251c1 | 314 | tree rval; |
0543e7a9 | 315 | tree argtype = TREE_TYPE (arg); |
471086d6 | 316 | tree target_type = TREE_TYPE (type); |
471086d6 | 317 | |
b4df430b | 318 | gcc_assert (TREE_CODE (type) == REFERENCE_TYPE); |
471086d6 | 319 | |
c76251c1 | 320 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 321 | { |
ca106ab1 | 322 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
323 | here because it needs to live as long as DECL. */ | |
c76251c1 | 324 | tree targ = arg; |
ca106ab1 | 325 | |
5ab1aaca | 326 | arg = make_temporary_var_for_ref_to_temp (decl, target_type); |
c23ebfdd | 327 | |
328 | /* Process the initializer for the declaration. */ | |
38281c46 | 329 | DECL_INITIAL (arg) = targ; |
d91303a6 | 330 | cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE, |
011310f7 | 331 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 332 | } |
c76251c1 | 333 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
44189c16 | 334 | return get_target_expr_sfinae (arg, complain); |
1ad432f2 | 335 | |
ca106ab1 | 336 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 337 | address, transform all occurrences of the register, into a memory |
338 | reference we could win better. */ | |
44189c16 | 339 | rval = cp_build_addr_expr (arg, complain); |
15e55420 | 340 | if (rval == error_mark_node) |
341 | return error_mark_node; | |
342 | ||
6686e84d | 343 | if ((flags & LOOKUP_PROTECT) |
344 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
95397ff9 | 345 | && MAYBE_CLASS_TYPE_P (argtype) |
346 | && MAYBE_CLASS_TYPE_P (target_type)) | |
6686e84d | 347 | { |
7e6960e0 | 348 | /* We go through lookup_base for the access control. */ |
ae260dcc | 349 | tree binfo = lookup_base (argtype, target_type, ba_check, |
350 | NULL, complain); | |
6686e84d | 351 | if (binfo == error_mark_node) |
352 | return error_mark_node; | |
353 | if (binfo == NULL_TREE) | |
354 | return error_not_base_type (target_type, argtype); | |
c4698a21 | 355 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1, complain); |
6686e84d | 356 | } |
c76251c1 | 357 | else |
358 | rval | |
c4698a21 | 359 | = convert_to_pointer_force (build_pointer_type (target_type), |
360 | rval, complain); | |
8999978b | 361 | return build_nop (type, rval); |
471086d6 | 362 | } |
363 | ||
519ba62c | 364 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
365 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
366 | for diagnostics. | |
9031d10b | 367 | |
519ba62c | 368 | [dcl.init.ref] says that if an rvalue is used to |
369 | initialize a reference, then the reference must be to a | |
370 | non-volatile const type. */ | |
371 | ||
372 | static void | |
19b271a9 | 373 | diagnose_ref_binding (location_t loc, tree reftype, tree intype, tree decl) |
519ba62c | 374 | { |
375 | tree ttl = TREE_TYPE (reftype); | |
9031d10b | 376 | |
519ba62c | 377 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) |
378 | { | |
379 | const char *msg; | |
380 | ||
381 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
ca82e026 | 382 | msg = G_("initialization of volatile reference type %q#T from " |
383 | "rvalue of type %qT"); | |
519ba62c | 384 | else if (CP_TYPE_VOLATILE_P (ttl)) |
ca82e026 | 385 | msg = G_("conversion to volatile reference type %q#T " |
386 | "from rvalue of type %qT"); | |
519ba62c | 387 | else if (decl) |
ca82e026 | 388 | msg = G_("initialization of non-const reference type %q#T from " |
389 | "rvalue of type %qT"); | |
519ba62c | 390 | else |
ca82e026 | 391 | msg = G_("conversion to non-const reference type %q#T from " |
392 | "rvalue of type %qT"); | |
519ba62c | 393 | |
61f69bc9 | 394 | permerror (loc, msg, reftype, intype); |
519ba62c | 395 | } |
396 | } | |
397 | ||
471086d6 | 398 | /* For C++: Only need to do one-level references, but cannot |
399 | get tripped up on signed/unsigned differences. | |
400 | ||
d81e00a4 | 401 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
402 | initialized. It can be error_mark_node if we don't know the _DECL but | |
403 | we know it's an initialization. */ | |
471086d6 | 404 | |
471086d6 | 405 | tree |
35771a9a | 406 | convert_to_reference (tree reftype, tree expr, int convtype, |
c4698a21 | 407 | int flags, tree decl, tsubst_flags_t complain) |
471086d6 | 408 | { |
cd16867a | 409 | tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); |
410 | tree intype; | |
471086d6 | 411 | tree rval = NULL_TREE; |
1a3f833b | 412 | tree rval_as_conversion = NULL_TREE; |
1bc16cab | 413 | bool can_convert_intype_to_type; |
3df42822 | 414 | location_t loc = EXPR_LOC_OR_LOC (expr, input_location); |
1a3f833b | 415 | |
9031d10b | 416 | if (TREE_CODE (type) == FUNCTION_TYPE |
d32df6a6 | 417 | && TREE_TYPE (expr) == unknown_type_node) |
66bbeb85 | 418 | expr = instantiate_type (type, expr, complain); |
0a3b29ad | 419 | |
420 | if (expr == error_mark_node) | |
421 | return error_mark_node; | |
422 | ||
423 | intype = TREE_TYPE (expr); | |
cc4d0855 | 424 | |
b4df430b | 425 | gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE); |
ab12ed55 | 426 | gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE); |
471086d6 | 427 | |
471086d6 | 428 | intype = TYPE_MAIN_VARIANT (intype); |
429 | ||
b657f346 | 430 | can_convert_intype_to_type = can_convert_standard (type, intype, complain); |
66bbeb85 | 431 | |
1bc16cab | 432 | if (!can_convert_intype_to_type |
95397ff9 | 433 | && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype) |
1a3f833b | 434 | && ! (flags & LOOKUP_NO_CONVERSION)) |
435 | { | |
436 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
437 | ||
0a4be248 | 438 | rval_as_conversion |
8999978b | 439 | = build_type_conversion (reftype, expr); |
1a3f833b | 440 | |
441 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
442 | && real_lvalue_p (rval_as_conversion)) | |
443 | { | |
444 | expr = rval_as_conversion; | |
445 | rval_as_conversion = NULL_TREE; | |
446 | intype = type; | |
1bc16cab | 447 | can_convert_intype_to_type = 1; |
1a3f833b | 448 | } |
449 | } | |
450 | ||
b657f346 | 451 | if (((convtype & CONV_STATIC) |
452 | && can_convert_standard (intype, type, complain)) | |
1bc16cab | 453 | || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type)) |
471086d6 | 454 | { |
c4698a21 | 455 | { |
456 | tree ttl = TREE_TYPE (reftype); | |
457 | tree ttr = lvalue_type (expr); | |
471086d6 | 458 | |
19b271a9 | 459 | if ((complain & tf_error) |
c4698a21 | 460 | && ! real_lvalue_p (expr)) |
19b271a9 | 461 | diagnose_ref_binding (loc, reftype, intype, decl); |
9031d10b | 462 | |
c4698a21 | 463 | if (! (convtype & CONV_CONST) |
464 | && !at_least_as_qualified_p (ttl, ttr)) | |
465 | { | |
466 | if (complain & tf_error) | |
467 | permerror (loc, "conversion from %qT to %qT discards qualifiers", | |
468 | ttr, reftype); | |
469 | else | |
470 | return error_mark_node; | |
471 | } | |
472 | } | |
0543e7a9 | 473 | |
c4698a21 | 474 | return build_up_reference (reftype, expr, flags, decl, complain); |
471086d6 | 475 | } |
c07b1ad1 | 476 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 477 | { |
478 | /* When casting an lvalue to a reference type, just convert into | |
479 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 480 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 481 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 482 | |
3748625f | 483 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
653e5405 | 484 | meant. */ |
c4698a21 | 485 | if ((complain & tf_warning) |
c21c015b | 486 | && TYPE_PTR_P (intype) |
a09db423 | 487 | && (comptypes (TREE_TYPE (intype), type, |
488 | COMPARE_BASE | COMPARE_DERIVED))) | |
61f69bc9 | 489 | warning_at (loc, 0, "casting %qT to %qT does not dereference pointer", |
490 | intype, reftype); | |
9031d10b | 491 | |
c4698a21 | 492 | rval = cp_build_addr_expr (expr, complain); |
0543e7a9 | 493 | if (rval != error_mark_node) |
985e9ee0 | 494 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
c4698a21 | 495 | rval, 0, complain); |
0543e7a9 | 496 | if (rval != error_mark_node) |
b0722fac | 497 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 498 | } |
0a4be248 | 499 | else |
860740a7 | 500 | { |
501 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
c4698a21 | 502 | ICR_CONVERTING, 0, 0, complain); |
a66fe4cb | 503 | if (rval == NULL_TREE || rval == error_mark_node) |
504 | return rval; | |
19b271a9 | 505 | if (complain & tf_error) |
506 | diagnose_ref_binding (loc, reftype, intype, decl); | |
c4698a21 | 507 | rval = build_up_reference (reftype, rval, flags, decl, complain); |
860740a7 | 508 | } |
471086d6 | 509 | |
510 | if (rval) | |
511 | { | |
96624a9e | 512 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 513 | return rval; |
514 | } | |
515 | ||
c4698a21 | 516 | if (complain & tf_error) |
61f69bc9 | 517 | error_at (loc, "cannot convert type %qT to type %qT", intype, reftype); |
b248d3f7 | 518 | |
471086d6 | 519 | return error_mark_node; |
520 | } | |
521 | ||
522 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 523 | way down to its lowest form. */ |
524 | ||
471086d6 | 525 | tree |
35771a9a | 526 | convert_from_reference (tree val) |
471086d6 | 527 | { |
73bdcca2 | 528 | if (TREE_TYPE (val) |
529 | && TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE) | |
729f89ff | 530 | { |
2fb61329 | 531 | tree t = TREE_TYPE (TREE_TYPE (val)); |
729f89ff | 532 | tree ref = build1 (INDIRECT_REF, t, val); |
9031d10b | 533 | |
3d37a176 | 534 | mark_exp_read (val); |
729f89ff | 535 | /* We *must* set TREE_READONLY when dereferencing a pointer to const, |
536 | so that we get the proper error message if the result is used | |
537 | to assign to. Also, &* is supposed to be a no-op. */ | |
538 | TREE_READONLY (ref) = CP_TYPE_CONST_P (t); | |
539 | TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); | |
540 | TREE_SIDE_EFFECTS (ref) | |
541 | = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val)); | |
729f89ff | 542 | val = ref; |
543 | } | |
9031d10b | 544 | |
471086d6 | 545 | return val; |
546 | } | |
e5dab226 | 547 | |
548 | /* Really perform an lvalue-to-rvalue conversion, including copying an | |
549 | argument of class type into a temporary. */ | |
550 | ||
551 | tree | |
9e505437 | 552 | force_rvalue (tree expr, tsubst_flags_t complain) |
e5dab226 | 553 | { |
9e505437 | 554 | tree type = TREE_TYPE (expr); |
555 | if (MAYBE_CLASS_TYPE_P (type) && TREE_CODE (expr) != TARGET_EXPR) | |
556 | { | |
f1f41a6c | 557 | vec<tree, va_gc> *args = make_tree_vector_single (expr); |
9e505437 | 558 | expr = build_special_member_call (NULL_TREE, complete_ctor_identifier, |
559 | &args, type, LOOKUP_NORMAL, complain); | |
560 | release_tree_vector (args); | |
561 | expr = build_cplus_new (type, expr, complain); | |
562 | } | |
e5dab226 | 563 | else |
4405c1ad | 564 | expr = decay_conversion (expr, complain); |
e5dab226 | 565 | |
566 | return expr; | |
567 | } | |
f5220369 | 568 | |
471086d6 | 569 | \f |
a1f05651 | 570 | /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has |
571 | TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR | |
572 | unchanged. */ | |
573 | ||
574 | static tree | |
575 | ignore_overflows (tree expr, tree orig) | |
576 | { | |
577 | if (TREE_CODE (expr) == INTEGER_CST | |
578 | && TREE_CODE (orig) == INTEGER_CST | |
579 | && TREE_OVERFLOW (expr) != TREE_OVERFLOW (orig)) | |
580 | { | |
581 | gcc_assert (!TREE_OVERFLOW (orig)); | |
582 | /* Ensure constant sharing. */ | |
e913b5cd | 583 | expr = wide_int_to_tree (TREE_TYPE (expr), expr); |
a1f05651 | 584 | } |
585 | return expr; | |
586 | } | |
587 | ||
588 | /* Fold away simple conversions, but make sure TREE_OVERFLOW is set | |
589 | properly. */ | |
f5220369 | 590 | |
591 | tree | |
592 | cp_fold_convert (tree type, tree expr) | |
593 | { | |
fe565588 | 594 | tree conv; |
595 | if (TREE_TYPE (expr) == type) | |
596 | conv = expr; | |
597 | else if (TREE_CODE (expr) == PTRMEM_CST) | |
598 | { | |
599 | /* Avoid wrapping a PTRMEM_CST in NOP_EXPR. */ | |
600 | conv = copy_node (expr); | |
601 | TREE_TYPE (conv) = type; | |
602 | } | |
603 | else | |
604 | { | |
605 | conv = fold_convert (type, expr); | |
606 | conv = ignore_overflows (conv, expr); | |
607 | } | |
a1f05651 | 608 | return conv; |
f5220369 | 609 | } |
610 | ||
c4a8ac95 | 611 | /* C++ conversions, preference to static cast conversions. */ |
612 | ||
613 | tree | |
c4698a21 | 614 | cp_convert (tree type, tree expr, tsubst_flags_t complain) |
c4a8ac95 | 615 | { |
c4698a21 | 616 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL, complain); |
c4a8ac95 | 617 | } |
618 | ||
59dd8856 | 619 | /* C++ equivalent of convert_and_check but using cp_convert as the |
620 | conversion function. | |
621 | ||
622 | Convert EXPR to TYPE, warning about conversion problems with constants. | |
623 | Invoke this function on every expression that is converted implicitly, | |
624 | i.e. because of language rules and not because of an explicit cast. */ | |
625 | ||
626 | tree | |
c4698a21 | 627 | cp_convert_and_check (tree type, tree expr, tsubst_flags_t complain) |
59dd8856 | 628 | { |
629 | tree result; | |
630 | ||
631 | if (TREE_TYPE (expr) == type) | |
632 | return expr; | |
d2c63826 | 633 | if (expr == error_mark_node) |
634 | return expr; | |
c4698a21 | 635 | result = cp_convert (type, expr, complain); |
59dd8856 | 636 | |
c4698a21 | 637 | if ((complain & tf_warning) |
65615944 | 638 | && c_inhibit_evaluation_warnings == 0) |
639 | { | |
d2c63826 | 640 | tree folded = cp_fully_fold (expr); |
641 | tree folded_result; | |
642 | if (folded == expr) | |
643 | folded_result = result; | |
644 | else | |
645 | { | |
646 | /* Avoid bogus -Wparentheses warnings. */ | |
93a735ed | 647 | warning_sentinel w (warn_parentheses); |
d2c63826 | 648 | folded_result = cp_convert (type, folded, tf_none); |
649 | } | |
650 | folded_result = fold_simple (folded_result); | |
651 | if (!TREE_OVERFLOW_P (folded) | |
65615944 | 652 | && folded_result != error_mark_node) |
3d27a0fa | 653 | warnings_for_convert_and_check (EXPR_LOC_OR_LOC (expr, input_location), |
654 | type, folded, folded_result); | |
65615944 | 655 | } |
59dd8856 | 656 | |
657 | return result; | |
658 | } | |
659 | ||
b248d3f7 | 660 | /* Conversion... |
661 | ||
662 | FLAGS indicates how we should behave. */ | |
663 | ||
471086d6 | 664 | tree |
c4698a21 | 665 | ocp_convert (tree type, tree expr, int convtype, int flags, |
666 | tsubst_flags_t complain) | |
471086d6 | 667 | { |
cd16867a | 668 | tree e = expr; |
669 | enum tree_code code = TREE_CODE (type); | |
7a979707 | 670 | const char *invalid_conv_diag; |
2b3c93a3 | 671 | tree e1; |
3df42822 | 672 | location_t loc = EXPR_LOC_OR_LOC (expr, input_location); |
471086d6 | 673 | |
1bc16cab | 674 | if (error_operand_p (e) || type == error_mark_node) |
471086d6 | 675 | return error_mark_node; |
d81e00a4 | 676 | |
5b592939 | 677 | complete_type (type); |
678 | complete_type (TREE_TYPE (expr)); | |
679 | ||
7a979707 | 680 | if ((invalid_conv_diag |
681 | = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
682 | { | |
c4698a21 | 683 | if (complain & tf_error) |
684 | error (invalid_conv_diag); | |
7a979707 | 685 | return error_mark_node; |
686 | } | |
687 | ||
ce984e5e | 688 | /* FIXME remove when moving to c_fully_fold model. */ |
0a7452a8 | 689 | if (!CLASS_TYPE_P (type)) |
690 | e = scalar_constant_value (e); | |
7a00f939 | 691 | if (error_operand_p (e)) |
692 | return error_mark_node; | |
7745052b | 693 | |
95397ff9 | 694 | if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP)) |
1a3f833b | 695 | /* We need a new temporary; don't take this shortcut. */; |
930e8175 | 696 | else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e))) |
ca23ec64 | 697 | { |
daf9ff67 | 698 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 699 | /* The call to fold will not always remove the NOP_EXPR as |
700 | might be expected, since if one of the types is a typedef; | |
755edffd | 701 | the comparison in fold is just equality of pointers, not a |
a09db423 | 702 | call to comptypes. We don't call fold in this case because |
f699c174 | 703 | that can result in infinite recursion; fold will call |
704 | convert, which will call ocp_convert, etc. */ | |
705 | return e; | |
372e0e29 | 706 | /* For complex data types, we need to perform componentwise |
653e5405 | 707 | conversion. */ |
372e0e29 | 708 | else if (TREE_CODE (type) == COMPLEX_TYPE) |
d2c63826 | 709 | return convert_to_complex_nofold (type, e); |
76249021 | 710 | else if (VECTOR_TYPE_P (type)) |
d2c63826 | 711 | return convert_to_vector (type, e); |
bdb2219e | 712 | else if (TREE_CODE (e) == TARGET_EXPR) |
713 | { | |
714 | /* Don't build a NOP_EXPR of class type. Instead, change the | |
930e8175 | 715 | type of the temporary. */ |
bdb2219e | 716 | TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type; |
717 | return e; | |
718 | } | |
ca23ec64 | 719 | else |
092b1d6f | 720 | { |
721 | /* We shouldn't be treating objects of ADDRESSABLE type as | |
722 | rvalues. */ | |
723 | gcc_assert (!TREE_ADDRESSABLE (type)); | |
d2c63826 | 724 | return build_nop (type, e); |
092b1d6f | 725 | } |
ca23ec64 | 726 | } |
727 | ||
2b3c93a3 | 728 | e1 = targetm.convert_to_type (type, e); |
729 | if (e1) | |
730 | return e1; | |
731 | ||
d81e00a4 | 732 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 733 | { |
c4698a21 | 734 | e = convert_to_void (e, ICV_CAST, complain); |
aeef2be5 | 735 | return e; |
95b2ac55 | 736 | } |
d81e00a4 | 737 | |
bb0726a1 | 738 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 739 | { |
617abf06 | 740 | tree intype = TREE_TYPE (e); |
a1f05651 | 741 | tree converted; |
384590d4 | 742 | |
743 | if (TREE_CODE (type) == ENUMERAL_TYPE) | |
744 | { | |
745 | /* enum = enum, enum = int, enum = float, (enum)pointer are all | |
746 | errors. */ | |
747 | if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype) | |
653e5405 | 748 | || TREE_CODE (intype) == REAL_TYPE) |
b312a686 | 749 | && ! (convtype & CONV_STATIC)) |
c21c015b | 750 | || TYPE_PTR_P (intype)) |
384590d4 | 751 | { |
c4698a21 | 752 | if (complain & tf_error) |
61f69bc9 | 753 | permerror (loc, "conversion from %q#T to %q#T", intype, type); |
c4698a21 | 754 | else |
384590d4 | 755 | return error_mark_node; |
756 | } | |
757 | ||
758 | /* [expr.static.cast] | |
759 | ||
760 | 8. A value of integral or enumeration type can be explicitly | |
761 | converted to an enumeration type. The value is unchanged if | |
762 | the original value is within the range of the enumeration | |
763 | values. Otherwise, the resulting enumeration value is | |
764 | unspecified. */ | |
c4698a21 | 765 | if ((complain & tf_warning) |
c28ddc97 | 766 | && TREE_CODE (e) == INTEGER_CST |
0116c9f8 | 767 | && ENUM_UNDERLYING_TYPE (type) |
c28ddc97 | 768 | && !int_fits_type_p (e, ENUM_UNDERLYING_TYPE (type))) |
61f69bc9 | 769 | warning_at (loc, OPT_Wconversion, |
770 | "the result of the conversion is unspecified because " | |
771 | "%qE is outside the range of type %qT", | |
772 | expr, type); | |
471086d6 | 773 | } |
95397ff9 | 774 | if (MAYBE_CLASS_TYPE_P (intype)) |
471086d6 | 775 | { |
776 | tree rval; | |
8999978b | 777 | rval = build_type_conversion (type, e); |
6495357a | 778 | if (rval) |
779 | return rval; | |
c4698a21 | 780 | if (complain & tf_error) |
61f69bc9 | 781 | error_at (loc, "%q#T used where a %qT was expected", intype, type); |
471086d6 | 782 | return error_mark_node; |
783 | } | |
bb0726a1 | 784 | if (code == BOOLEAN_TYPE) |
f8913d47 | 785 | { |
c21c015b | 786 | if (VOID_TYPE_P (intype)) |
61f69bc9 | 787 | { |
c4698a21 | 788 | if (complain & tf_error) |
789 | error_at (loc, | |
790 | "could not convert %qE from %<void%> to %<bool%>", | |
791 | expr); | |
61f69bc9 | 792 | return error_mark_node; |
793 | } | |
794 | ||
f8913d47 | 795 | /* We can't implicitly convert a scoped enum to bool, so convert |
796 | to the underlying type first. */ | |
797 | if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC)) | |
172fff7b | 798 | e = build_nop (ENUM_UNDERLYING_TYPE (intype), e); |
f8913d47 | 799 | return cp_truthvalue_conversion (e); |
800 | } | |
ce871053 | 801 | |
d2c63826 | 802 | converted = convert_to_integer_nofold (type, e); |
a1f05651 | 803 | |
804 | /* Ignore any integer overflow caused by the conversion. */ | |
805 | return ignore_overflows (converted, e); | |
471086d6 | 806 | } |
c7ca48ea | 807 | if (NULLPTR_TYPE_P (type) && e && null_ptr_cst_p (e)) |
49858f84 | 808 | { |
809 | if (complain & tf_warning) | |
810 | maybe_warn_zero_as_null_pointer_constant (e, loc); | |
811 | return nullptr_node; | |
812 | } | |
05765a91 | 813 | if (POINTER_TYPE_P (type) || TYPE_PTRMEM_P (type)) |
d2c63826 | 814 | return cp_convert_to_pointer (type, e, complain); |
684b9d79 | 815 | if (code == VECTOR_TYPE) |
c37ff371 | 816 | { |
817 | tree in_vtype = TREE_TYPE (e); | |
95397ff9 | 818 | if (MAYBE_CLASS_TYPE_P (in_vtype)) |
c37ff371 | 819 | { |
820 | tree ret_val; | |
821 | ret_val = build_type_conversion (type, e); | |
653e5405 | 822 | if (ret_val) |
823 | return ret_val; | |
c4698a21 | 824 | if (complain & tf_error) |
825 | error_at (loc, "%q#T used where a %qT was expected", | |
826 | in_vtype, type); | |
653e5405 | 827 | return error_mark_node; |
c37ff371 | 828 | } |
d2c63826 | 829 | return convert_to_vector (type, e); |
c37ff371 | 830 | } |
c4a8ac95 | 831 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 832 | { |
95397ff9 | 833 | if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e))) |
471086d6 | 834 | { |
835 | tree rval; | |
8999978b | 836 | rval = build_type_conversion (type, e); |
471086d6 | 837 | if (rval) |
838 | return rval; | |
c4698a21 | 839 | else if (complain & tf_error) |
840 | error_at (loc, | |
841 | "%q#T used where a floating point value was expected", | |
842 | TREE_TYPE (e)); | |
471086d6 | 843 | } |
c4a8ac95 | 844 | if (code == REAL_TYPE) |
d2c63826 | 845 | return convert_to_real_nofold (type, e); |
c4a8ac95 | 846 | else if (code == COMPLEX_TYPE) |
d2c63826 | 847 | return convert_to_complex_nofold (type, e); |
471086d6 | 848 | } |
849 | ||
850 | /* New C++ semantics: since assignment is now based on | |
851 | memberwise copying, if the rhs type is derived from the | |
852 | lhs type, then we may still do a conversion. */ | |
95397ff9 | 853 | if (RECORD_OR_UNION_CODE_P (code)) |
471086d6 | 854 | { |
855 | tree dtype = TREE_TYPE (e); | |
c25194fd | 856 | tree ctor = NULL_TREE; |
471086d6 | 857 | |
471086d6 | 858 | dtype = TYPE_MAIN_VARIANT (dtype); |
859 | ||
471086d6 | 860 | /* Conversion between aggregate types. New C++ semantics allow |
861 | objects of derived type to be cast to objects of base type. | |
862 | Old semantics only allowed this between pointers. | |
863 | ||
864 | There may be some ambiguity between using a constructor | |
865 | vs. using a type conversion operator when both apply. */ | |
866 | ||
0a4be248 | 867 | ctor = e; |
860740a7 | 868 | |
44189c16 | 869 | if (abstract_virtuals_error_sfinae (NULL_TREE, type, complain)) |
8c18e707 | 870 | return error_mark_node; |
6cbb4197 | 871 | |
f82f1250 | 872 | if (BRACE_ENCLOSED_INITIALIZER_P (ctor)) |
c4698a21 | 873 | ctor = perform_implicit_conversion (type, ctor, complain); |
f82f1250 | 874 | else if ((flags & LOOKUP_ONLYCONVERTING) |
875 | && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 876 | /* For copy-initialization, first we create a temp of the proper type |
877 | with a user-defined conversion sequence, then we direct-initialize | |
878 | the target with the temp (see [dcl.init]). */ | |
c4698a21 | 879 | ctor = build_user_type_conversion (type, ctor, flags, complain); |
3eb89cd8 | 880 | else |
f352a3fb | 881 | { |
f1f41a6c | 882 | vec<tree, va_gc> *ctor_vec = make_tree_vector_single (ctor); |
f352a3fb | 883 | ctor = build_special_member_call (NULL_TREE, |
884 | complete_ctor_identifier, | |
885 | &ctor_vec, | |
c4698a21 | 886 | type, flags, complain); |
f352a3fb | 887 | release_tree_vector (ctor_vec); |
888 | } | |
0a4be248 | 889 | if (ctor) |
c4698a21 | 890 | return build_cplus_new (type, ctor, complain); |
471086d6 | 891 | } |
892 | ||
c4698a21 | 893 | if (complain & tf_error) |
a7cc1549 | 894 | { |
895 | /* If the conversion failed and expr was an invalid use of pointer to | |
896 | member function, try to report a meaningful error. */ | |
5c874cd3 | 897 | if (invalid_nonstatic_memfn_p (loc, expr, complain)) |
a7cc1549 | 898 | /* We displayed the error message. */; |
899 | else | |
61f69bc9 | 900 | error_at (loc, "conversion from %qT to non-scalar type %qT requested", |
901 | TREE_TYPE (expr), type); | |
a7cc1549 | 902 | } |
471086d6 | 903 | return error_mark_node; |
904 | } | |
905 | ||
b1a8d4ce | 906 | /* When an expression is used in a void context, its value is discarded and |
907 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
908 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
909 | in a void context. The C++ standard does not define what an `access' to an | |
63eff20d | 910 | object is, but there is reason to believe that it is the lvalue to rvalue |
b1a8d4ce | 911 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it |
912 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
913 | indicates that volatile semantics should be the same between C and C++ | |
914 | where ever possible. C leaves it implementation defined as to what | |
915 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
916 | the volatile object `vp' points to, unless that is an incomplete type. For | |
917 | volatile references we do not do this interpretation, because that would | |
918 | make it impossible to ignore the reference return value from functions. We | |
919 | issue warnings in the confusing cases. | |
9031d10b | 920 | |
dab3247a | 921 | The IMPLICIT is ICV_CAST when the user is explicitly converting an expression |
922 | to void via a cast. If an expression is being implicitly converted, IMPLICIT | |
923 | indicates the context of the implicit conversion. */ | |
b1a8d4ce | 924 | |
925 | tree | |
dab3247a | 926 | convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain) |
b1a8d4ce | 927 | { |
3df42822 | 928 | location_t loc = EXPR_LOC_OR_LOC (expr, input_location); |
61f69bc9 | 929 | |
9031d10b | 930 | if (expr == error_mark_node |
3d411d73 | 931 | || TREE_TYPE (expr) == error_mark_node) |
932 | return error_mark_node; | |
b2af2a93 | 933 | |
dab3247a | 934 | if (implicit == ICV_CAST) |
f94341bb | 935 | mark_exp_read (expr); |
936 | else | |
937 | { | |
938 | tree exprv = expr; | |
939 | ||
940 | while (TREE_CODE (exprv) == COMPOUND_EXPR) | |
941 | exprv = TREE_OPERAND (exprv, 1); | |
0388391d | 942 | if (DECL_P (exprv) |
943 | || handled_component_p (exprv) | |
86ccc124 | 944 | || INDIRECT_REF_P (exprv)) |
f94341bb | 945 | /* Expr is not being 'used' here, otherwise we whould have |
946 | called mark_{rl}value_use use here, which would have in turn | |
947 | called mark_exp_read. Rather, we call mark_exp_read directly | |
948 | to avoid some warnings when | |
949 | -Wunused-but-set-{variable,parameter} is in effect. */ | |
950 | mark_exp_read (exprv); | |
951 | } | |
b2af2a93 | 952 | |
b1a8d4ce | 953 | if (!TREE_TYPE (expr)) |
954 | return expr; | |
5c874cd3 | 955 | if (invalid_nonstatic_memfn_p (loc, expr, complain)) |
334f6ce1 | 956 | return error_mark_node; |
ed36f1cf | 957 | if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR) |
958 | { | |
ebd21de4 | 959 | if (complain & tf_error) |
61f69bc9 | 960 | error_at (loc, "pseudo-destructor is not called"); |
ed36f1cf | 961 | return error_mark_node; |
962 | } | |
e3cfe3ce | 963 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 964 | return expr; |
965 | switch (TREE_CODE (expr)) | |
966 | { | |
967 | case COND_EXPR: | |
968 | { | |
653e5405 | 969 | /* The two parts of a cond expr might be separate lvalues. */ |
970 | tree op1 = TREE_OPERAND (expr,1); | |
971 | tree op2 = TREE_OPERAND (expr,2); | |
527facbb | 972 | bool side_effects = ((op1 && TREE_SIDE_EFFECTS (op1)) |
973 | || TREE_SIDE_EFFECTS (op2)); | |
dab3247a | 974 | tree new_op1, new_op2; |
527facbb | 975 | new_op1 = NULL_TREE; |
dab3247a | 976 | if (implicit != ICV_CAST && !side_effects) |
977 | { | |
527facbb | 978 | if (op1) |
979 | new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain); | |
dab3247a | 980 | new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain); |
981 | } | |
982 | else | |
983 | { | |
527facbb | 984 | if (op1) |
985 | new_op1 = convert_to_void (op1, ICV_CAST, complain); | |
dab3247a | 986 | new_op2 = convert_to_void (op2, ICV_CAST, complain); |
987 | } | |
9031d10b | 988 | |
527facbb | 989 | expr = build3 (COND_EXPR, TREE_TYPE (new_op2), |
831d52a2 | 990 | TREE_OPERAND (expr, 0), new_op1, new_op2); |
653e5405 | 991 | break; |
b1a8d4ce | 992 | } |
9031d10b | 993 | |
b1a8d4ce | 994 | case COMPOUND_EXPR: |
995 | { | |
653e5405 | 996 | /* The second part of a compound expr contains the value. */ |
997 | tree op1 = TREE_OPERAND (expr,1); | |
dab3247a | 998 | tree new_op1; |
999 | if (implicit != ICV_CAST && !TREE_NO_WARNING (expr)) | |
1000 | new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain); | |
1001 | else | |
1002 | new_op1 = convert_to_void (op1, ICV_CAST, complain); | |
9031d10b | 1003 | |
653e5405 | 1004 | if (new_op1 != op1) |
e907a2e9 | 1005 | { |
831d52a2 | 1006 | tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1), |
1007 | TREE_OPERAND (expr, 0), new_op1); | |
e907a2e9 | 1008 | expr = t; |
1009 | } | |
1010 | ||
653e5405 | 1011 | break; |
b1a8d4ce | 1012 | } |
9031d10b | 1013 | |
b1a8d4ce | 1014 | case NON_LVALUE_EXPR: |
1015 | case NOP_EXPR: | |
c0af329c | 1016 | /* These have already decayed to rvalue. */ |
b1a8d4ce | 1017 | break; |
9031d10b | 1018 | |
331bc0ad | 1019 | case CALL_EXPR: /* We have a special meaning for volatile void fn(). */ |
b1a8d4ce | 1020 | break; |
9031d10b | 1021 | |
b1a8d4ce | 1022 | case INDIRECT_REF: |
1023 | { | |
653e5405 | 1024 | tree type = TREE_TYPE (expr); |
1025 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
1026 | == REFERENCE_TYPE; | |
1027 | int is_volatile = TYPE_VOLATILE (type); | |
1028 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
1029 | ||
dc02da7f | 1030 | /* Can't load the value if we don't know the type. */ |
653e5405 | 1031 | if (is_volatile && !is_complete) |
ebd21de4 | 1032 | { |
1033 | if (complain & tf_warning) | |
dab3247a | 1034 | switch (implicit) |
1035 | { | |
1036 | case ICV_CAST: | |
61f69bc9 | 1037 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1038 | "object of incomplete type %qT", type); |
1039 | break; | |
1040 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1041 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1042 | "incomplete type %qT in second operand " |
1043 | "of conditional expression", type); | |
1044 | break; | |
1045 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1046 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1047 | "incomplete type %qT in third operand " |
1048 | "of conditional expression", type); | |
1049 | break; | |
1050 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1051 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1052 | "incomplete type %qT in right operand of " |
1053 | "comma operator", type); | |
1054 | break; | |
1055 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1056 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1057 | "incomplete type %qT in left operand of " |
1058 | "comma operator", type); | |
1059 | break; | |
1060 | case ICV_STATEMENT: | |
61f69bc9 | 1061 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1062 | "incomplete type %qT in statement", type); |
1063 | break; | |
1064 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1065 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1066 | "incomplete type %qT in for increment " |
1067 | "expression", type); | |
1068 | break; | |
1069 | default: | |
1070 | gcc_unreachable (); | |
1071 | } | |
ebd21de4 | 1072 | } |
dc02da7f | 1073 | /* Don't load the value if this is an implicit dereference, or if |
1074 | the type needs to be handled by ctors/dtors. */ | |
dab3247a | 1075 | else if (is_volatile && is_reference) |
ebd21de4 | 1076 | { |
1077 | if (complain & tf_warning) | |
dab3247a | 1078 | switch (implicit) |
1079 | { | |
1080 | case ICV_CAST: | |
61f69bc9 | 1081 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1082 | "object of type %qT", type); |
1083 | break; | |
1084 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1085 | warning_at (loc, 0, "implicit dereference will not access " |
1086 | "object of type %qT in second operand of " | |
dab3247a | 1087 | "conditional expression", type); |
1088 | break; | |
1089 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1090 | warning_at (loc, 0, "implicit dereference will not access " |
1091 | "object of type %qT in third operand of " | |
dab3247a | 1092 | "conditional expression", type); |
1093 | break; | |
1094 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1095 | warning_at (loc, 0, "implicit dereference will not access " |
1096 | "object of type %qT in right operand of " | |
dab3247a | 1097 | "comma operator", type); |
1098 | break; | |
1099 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1100 | warning_at (loc, 0, "implicit dereference will not access " |
1101 | "object of type %qT in left operand of comma " | |
1102 | "operator", type); | |
dab3247a | 1103 | break; |
1104 | case ICV_STATEMENT: | |
61f69bc9 | 1105 | warning_at (loc, 0, "implicit dereference will not access " |
1106 | "object of type %qT in statement", type); | |
dab3247a | 1107 | break; |
1108 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1109 | warning_at (loc, 0, "implicit dereference will not access " |
1110 | "object of type %qT in for increment expression", | |
1111 | type); | |
dab3247a | 1112 | break; |
1113 | default: | |
1114 | gcc_unreachable (); | |
1115 | } | |
ebd21de4 | 1116 | } |
dab3247a | 1117 | else if (is_volatile && TREE_ADDRESSABLE (type)) |
1118 | { | |
1119 | if (complain & tf_warning) | |
1120 | switch (implicit) | |
1121 | { | |
1122 | case ICV_CAST: | |
61f69bc9 | 1123 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1124 | "object of non-trivially-copyable type %qT", |
61f69bc9 | 1125 | type); |
dab3247a | 1126 | break; |
1127 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1128 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1129 | "non-trivially-copyable type %qT in second " |
1130 | "operand of conditional expression", type); | |
1131 | break; | |
1132 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1133 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1134 | "non-trivially-copyable type %qT in third " |
1135 | "operand of conditional expression", type); | |
1136 | break; | |
1137 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1138 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1139 | "non-trivially-copyable type %qT in right " |
1140 | "operand of comma operator", type); | |
1141 | break; | |
1142 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1143 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1144 | "non-trivially-copyable type %qT in left " |
1145 | "operand of comma operator", type); | |
1146 | break; | |
1147 | case ICV_STATEMENT: | |
61f69bc9 | 1148 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1149 | "non-trivially-copyable type %qT in statement", |
61f69bc9 | 1150 | type); |
dab3247a | 1151 | break; |
1152 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1153 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1154 | "non-trivially-copyable type %qT in for " |
1155 | "increment expression", type); | |
1156 | break; | |
1157 | default: | |
1158 | gcc_unreachable (); | |
1159 | } | |
1160 | } | |
dc02da7f | 1161 | if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type)) |
a4d4030b | 1162 | { |
1163 | /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF | |
1164 | operation is stripped off. Note that we don't warn about | |
1165 | - an expression with TREE_NO_WARNING set. (For an example of | |
1166 | such expressions, see build_over_call in call.c.) | |
1167 | - automatic dereferencing of references, since the user cannot | |
3d177e8c | 1168 | control it. (See also warn_if_unused_value() in c-common.c.) */ |
a4d4030b | 1169 | if (warn_unused_value |
dab3247a | 1170 | && implicit != ICV_CAST |
a4d4030b | 1171 | && (complain & tf_warning) |
1172 | && !TREE_NO_WARNING (expr) | |
1173 | && !is_reference) | |
61f69bc9 | 1174 | warning_at (loc, OPT_Wunused_value, "value computed is not used"); |
a4d4030b | 1175 | expr = TREE_OPERAND (expr, 0); |
1176 | } | |
653e5405 | 1177 | |
1178 | break; | |
b1a8d4ce | 1179 | } |
9031d10b | 1180 | |
b1a8d4ce | 1181 | case VAR_DECL: |
1182 | { | |
653e5405 | 1183 | /* External variables might be incomplete. */ |
1184 | tree type = TREE_TYPE (expr); | |
1185 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
1186 | ||
ebd21de4 | 1187 | if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning)) |
dab3247a | 1188 | switch (implicit) |
1189 | { | |
1190 | case ICV_CAST: | |
61f69bc9 | 1191 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1192 | "object %qE of incomplete type %qT", expr, type); |
1193 | break; | |
1194 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1195 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1196 | "not be accessed in second operand of " | |
dab3247a | 1197 | "conditional expression", expr, type); |
1198 | break; | |
1199 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1200 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1201 | "not be accessed in third operand of " | |
dab3247a | 1202 | "conditional expression", expr, type); |
1203 | break; | |
1204 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1205 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1206 | "not be accessed in right operand of comma operator", | |
1207 | expr, type); | |
dab3247a | 1208 | break; |
1209 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1210 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1211 | "not be accessed in left operand of comma operator", | |
1212 | expr, type); | |
dab3247a | 1213 | break; |
1214 | case ICV_STATEMENT: | |
61f69bc9 | 1215 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1216 | "not be accessed in statement", expr, type); | |
dab3247a | 1217 | break; |
1218 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1219 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1220 | "not be accessed in for increment expression", | |
1221 | expr, type); | |
dab3247a | 1222 | break; |
1223 | default: | |
1224 | gcc_unreachable (); | |
1225 | } | |
1226 | ||
653e5405 | 1227 | break; |
b1a8d4ce | 1228 | } |
d9f88785 | 1229 | |
25b3017b | 1230 | case TARGET_EXPR: |
1231 | /* Don't bother with the temporary object returned from a function if | |
1fe75cf2 | 1232 | we don't use it, don't need to destroy it, and won't abort in |
1233 | assign_temp. We'll still | |
25b3017b | 1234 | allocate space for it in expand_call or declare_return_variable, |
1235 | but we don't need to track it through all the tree phases. */ | |
67bb1301 | 1236 | if (TARGET_EXPR_IMPLICIT_P (expr) |
1fe75cf2 | 1237 | && !TREE_ADDRESSABLE (TREE_TYPE (expr))) |
25b3017b | 1238 | { |
1239 | tree init = TARGET_EXPR_INITIAL (expr); | |
1240 | if (TREE_CODE (init) == AGGR_INIT_EXPR | |
1241 | && !AGGR_INIT_VIA_CTOR_P (init)) | |
1242 | { | |
c2f47e15 | 1243 | tree fn = AGGR_INIT_EXPR_FN (init); |
389dd41b | 1244 | expr = build_call_array_loc (input_location, |
1245 | TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))), | |
1246 | fn, | |
1247 | aggr_init_expr_nargs (init), | |
1248 | AGGR_INIT_EXPR_ARGP (init)); | |
25b3017b | 1249 | } |
1250 | } | |
1251 | break; | |
1252 | ||
b1a8d4ce | 1253 | default:; |
1254 | } | |
eebd67e7 | 1255 | expr = resolve_nondeduced_context (expr); |
b1a8d4ce | 1256 | { |
1257 | tree probe = expr; | |
9031d10b | 1258 | |
b1a8d4ce | 1259 | if (TREE_CODE (probe) == ADDR_EXPR) |
1260 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 1261 | if (type_unknown_p (probe)) |
1262 | { | |
1263 | /* [over.over] enumerates the places where we can take the address | |
1264 | of an overloaded function, and this is not one of them. */ | |
ebd21de4 | 1265 | if (complain & tf_error) |
dab3247a | 1266 | switch (implicit) |
1267 | { | |
1268 | case ICV_CAST: | |
61f69bc9 | 1269 | error_at (loc, "conversion to void " |
1270 | "cannot resolve address of overloaded function"); | |
dab3247a | 1271 | break; |
1272 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1273 | error_at (loc, "second operand of conditional expression " |
1274 | "cannot resolve address of overloaded function"); | |
dab3247a | 1275 | break; |
1276 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1277 | error_at (loc, "third operand of conditional expression " |
1278 | "cannot resolve address of overloaded function"); | |
dab3247a | 1279 | break; |
1280 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1281 | error_at (loc, "right operand of comma operator " |
1282 | "cannot resolve address of overloaded function"); | |
dab3247a | 1283 | break; |
1284 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1285 | error_at (loc, "left operand of comma operator " |
1286 | "cannot resolve address of overloaded function"); | |
dab3247a | 1287 | break; |
1288 | case ICV_STATEMENT: | |
61f69bc9 | 1289 | error_at (loc, "statement " |
1290 | "cannot resolve address of overloaded function"); | |
dab3247a | 1291 | break; |
1292 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1293 | error_at (loc, "for increment expression " |
1294 | "cannot resolve address of overloaded function"); | |
dab3247a | 1295 | break; |
1296 | } | |
ebd21de4 | 1297 | else |
1298 | return error_mark_node; | |
3ab4693e | 1299 | expr = void_node; |
2e0e6579 | 1300 | } |
dab3247a | 1301 | else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe)) |
2056769e | 1302 | { |
1303 | /* Only warn when there is no &. */ | |
ebd21de4 | 1304 | if (complain & tf_warning) |
dab3247a | 1305 | switch (implicit) |
1306 | { | |
1307 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1308 | warning_at (loc, OPT_Waddress, |
1309 | "second operand of conditional expression " | |
1310 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1311 | break; |
1312 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1313 | warning_at (loc, OPT_Waddress, |
1314 | "third operand of conditional expression " | |
1315 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1316 | break; |
1317 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1318 | warning_at (loc, OPT_Waddress, |
1319 | "right operand of comma operator " | |
1320 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1321 | break; |
1322 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1323 | warning_at (loc, OPT_Waddress, |
1324 | "left operand of comma operator " | |
1325 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1326 | break; |
1327 | case ICV_STATEMENT: | |
61f69bc9 | 1328 | warning_at (loc, OPT_Waddress, |
1329 | "statement is a reference, not call, to function %qE", | |
1330 | expr); | |
dab3247a | 1331 | break; |
1332 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1333 | warning_at (loc, OPT_Waddress, |
1334 | "for increment expression " | |
1335 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1336 | break; |
1337 | default: | |
1338 | gcc_unreachable (); | |
1339 | } | |
1340 | ||
2056769e | 1341 | if (TREE_CODE (expr) == COMPONENT_REF) |
1342 | expr = TREE_OPERAND (expr, 0); | |
1343 | } | |
b1a8d4ce | 1344 | } |
9031d10b | 1345 | |
e3cfe3ce | 1346 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 1347 | { |
dab3247a | 1348 | if (implicit != ICV_CAST |
5e2a4133 | 1349 | && warn_unused_value |
1350 | && !TREE_NO_WARNING (expr) | |
1351 | && !processing_template_decl) | |
1fe46df1 | 1352 | { |
1353 | /* The middle end does not warn about expressions that have | |
1354 | been explicitly cast to void, so we must do so here. */ | |
ebd21de4 | 1355 | if (!TREE_SIDE_EFFECTS (expr)) { |
1356 | if (complain & tf_warning) | |
dab3247a | 1357 | switch (implicit) |
1358 | { | |
1359 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1360 | warning_at (loc, OPT_Wunused_value, |
1361 | "second operand of conditional expression " | |
1362 | "has no effect"); | |
dab3247a | 1363 | break; |
1364 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1365 | warning_at (loc, OPT_Wunused_value, |
1366 | "third operand of conditional expression " | |
1367 | "has no effect"); | |
dab3247a | 1368 | break; |
1369 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1370 | warning_at (loc, OPT_Wunused_value, |
1371 | "right operand of comma operator has no effect"); | |
dab3247a | 1372 | break; |
1373 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1374 | warning_at (loc, OPT_Wunused_value, |
1375 | "left operand of comma operator has no effect"); | |
dab3247a | 1376 | break; |
1377 | case ICV_STATEMENT: | |
61f69bc9 | 1378 | warning_at (loc, OPT_Wunused_value, |
1379 | "statement has no effect"); | |
dab3247a | 1380 | break; |
1381 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1382 | warning_at (loc, OPT_Wunused_value, |
1383 | "for increment expression has no effect"); | |
dab3247a | 1384 | break; |
1385 | default: | |
1386 | gcc_unreachable (); | |
1387 | } | |
ebd21de4 | 1388 | } |
9031d10b | 1389 | else |
1390 | { | |
1fe46df1 | 1391 | tree e; |
1392 | enum tree_code code; | |
607a5d68 | 1393 | enum tree_code_class tclass; |
9031d10b | 1394 | |
1fe46df1 | 1395 | e = expr; |
1396 | /* We might like to warn about (say) "(int) f()", as the | |
1397 | cast has no effect, but the compiler itself will | |
1398 | generate implicit conversions under some | |
324d8f2d | 1399 | circumstances. (For example a block copy will be |
1fe46df1 | 1400 | turned into a call to "__builtin_memcpy", with a |
1401 | conversion of the return value to an appropriate | |
1402 | type.) So, to avoid false positives, we strip | |
416ce344 | 1403 | conversions. Do not use STRIP_NOPs because it will |
1404 | not strip conversions to "void", as that is not a | |
1405 | mode-preserving conversion. */ | |
1406 | while (TREE_CODE (e) == NOP_EXPR) | |
1407 | e = TREE_OPERAND (e, 0); | |
1fe46df1 | 1408 | |
1409 | code = TREE_CODE (e); | |
607a5d68 | 1410 | tclass = TREE_CODE_CLASS (code); |
1411 | if ((tclass == tcc_comparison | |
1412 | || tclass == tcc_unary | |
1413 | || (tclass == tcc_binary | |
1fe46df1 | 1414 | && !(code == MODIFY_EXPR |
1415 | || code == INIT_EXPR | |
1416 | || code == PREDECREMENT_EXPR | |
1417 | || code == PREINCREMENT_EXPR | |
1418 | || code == POSTDECREMENT_EXPR | |
9372a89d | 1419 | || code == POSTINCREMENT_EXPR)) |
1420 | || code == VEC_PERM_EXPR | |
1421 | || code == VEC_COND_EXPR) | |
ebd21de4 | 1422 | && (complain & tf_warning)) |
61f69bc9 | 1423 | warning_at (loc, OPT_Wunused_value, "value computed is not used"); |
1fe46df1 | 1424 | } |
1425 | } | |
00fa9079 | 1426 | expr = build1 (CONVERT_EXPR, void_type_node, expr); |
b1a8d4ce | 1427 | } |
de5ad4cb | 1428 | if (! TREE_SIDE_EFFECTS (expr)) |
3ab4693e | 1429 | expr = void_node; |
b1a8d4ce | 1430 | return expr; |
1431 | } | |
1432 | ||
d81e00a4 | 1433 | /* Create an expression whose value is that of EXPR, |
1434 | converted to type TYPE. The TREE_TYPE of the value | |
1435 | is always TYPE. This function implements all reasonable | |
1436 | conversions; callers should filter out those that are | |
c4a8ac95 | 1437 | not permitted by the language being compiled. |
1438 | ||
1439 | Most of this routine is from build_reinterpret_cast. | |
1440 | ||
a17c2a3a | 1441 | The back end cannot call cp_convert (what was convert) because |
c4a8ac95 | 1442 | conversions to/from basetypes may involve memory references |
1443 | (vbases) and adding or subtracting small values (multiple | |
1444 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 1445 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 1446 | |
1447 | Also, if we ever support range variables, we'll probably also have to | |
1448 | do a little bit more work. */ | |
d81e00a4 | 1449 | |
1450 | tree | |
35771a9a | 1451 | convert (tree type, tree expr) |
d81e00a4 | 1452 | { |
c4a8ac95 | 1453 | tree intype; |
1454 | ||
1455 | if (type == error_mark_node || expr == error_mark_node) | |
1456 | return error_mark_node; | |
1457 | ||
c4a8ac95 | 1458 | intype = TREE_TYPE (expr); |
1459 | ||
6686e84d | 1460 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
d2c63826 | 1461 | return build_nop (type, expr); |
c4a8ac95 | 1462 | |
1463 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
c4698a21 | 1464 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION, |
1465 | tf_warning_or_error); | |
d81e00a4 | 1466 | } |
1467 | ||
c4a8ac95 | 1468 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 1469 | are not normally allowed due to access restrictions |
1470 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 1471 | |
471086d6 | 1472 | tree |
c4698a21 | 1473 | convert_force (tree type, tree expr, int convtype, tsubst_flags_t complain) |
471086d6 | 1474 | { |
cd16867a | 1475 | tree e = expr; |
1476 | enum tree_code code = TREE_CODE (type); | |
471086d6 | 1477 | |
1478 | if (code == REFERENCE_TYPE) | |
d2c63826 | 1479 | return convert_to_reference (type, e, CONV_C_CAST, 0, |
1480 | NULL_TREE, complain); | |
471086d6 | 1481 | |
1482 | if (code == POINTER_TYPE) | |
d2c63826 | 1483 | return convert_to_pointer_force (type, e, complain); |
471086d6 | 1484 | |
ac9386a0 | 1485 | /* From typeck.c convert_for_assignment */ |
c21c015b | 1486 | if (((TYPE_PTR_P (TREE_TYPE (e)) && TREE_CODE (e) == ADDR_EXPR |
471086d6 | 1487 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) |
ac9386a0 | 1488 | || integer_zerop (e) |
1489 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1490 | && TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 1491 | /* compatible pointer to member functions. */ |
1492 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1, | |
c4698a21 | 1493 | /*c_cast_p=*/1, complain); |
a74e8896 | 1494 | |
c4698a21 | 1495 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL, complain); |
471086d6 | 1496 | } |
1497 | ||
471086d6 | 1498 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1499 | exists, return the attempted conversion. This may | |
1500 | return ERROR_MARK_NODE if the conversion is not | |
1501 | allowed (references private members, etc). | |
1502 | If no conversion exists, NULL_TREE is returned. | |
1503 | ||
ce28ee2e | 1504 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit |
1505 | object parameter, or by the second standard conversion sequence if | |
1506 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1507 | (jason 8/9/95) */ | |
471086d6 | 1508 | |
ef9571e5 | 1509 | static tree |
8999978b | 1510 | build_type_conversion (tree xtype, tree expr) |
471086d6 | 1511 | { |
1512 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1513 | into the required type. */ |
66bbeb85 | 1514 | return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL, |
1515 | tf_warning_or_error); | |
471086d6 | 1516 | } |
1517 | ||
1e66592c | 1518 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1519 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
35771a9a | 1520 | which indicates which types are suitable. If COMPLAIN is true, complain |
1e66592c | 1521 | about ambiguity; otherwise, the caller will deal with it. */ |
471086d6 | 1522 | |
1e66592c | 1523 | tree |
35771a9a | 1524 | build_expr_type_conversion (int desires, tree expr, bool complain) |
471086d6 | 1525 | { |
1e66592c | 1526 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1527 | tree conv = NULL_TREE; |
bdd152ce | 1528 | tree winner = NULL_TREE; |
471086d6 | 1529 | |
9031d10b | 1530 | if (expr == null_node |
1531 | && (desires & WANT_INT) | |
954885ed | 1532 | && !(desires & WANT_NULL)) |
db30b351 | 1533 | { |
1534 | source_location loc = | |
1535 | expansion_point_location_if_in_system_header (input_location); | |
1536 | ||
1537 | warning_at (loc, OPT_Wconversion_null, | |
1538 | "converting NULL to non-pointer type"); | |
1539 | } | |
9031d10b | 1540 | |
3d411d73 | 1541 | if (basetype == error_mark_node) |
1542 | return error_mark_node; | |
1543 | ||
95397ff9 | 1544 | if (! MAYBE_CLASS_TYPE_P (basetype)) |
bdd152ce | 1545 | switch (TREE_CODE (basetype)) |
1546 | { | |
1547 | case INTEGER_TYPE: | |
954885ed | 1548 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1549 | return expr; |
1550 | /* else fall through... */ | |
1551 | ||
1552 | case BOOLEAN_TYPE: | |
1553 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1554 | case ENUMERAL_TYPE: | |
1555 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1556 | case REAL_TYPE: | |
1557 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1558 | case POINTER_TYPE: | |
1559 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
9031d10b | 1560 | |
bdd152ce | 1561 | case FUNCTION_TYPE: |
1562 | case ARRAY_TYPE: | |
4405c1ad | 1563 | return (desires & WANT_POINTER) ? decay_conversion (expr, |
1564 | tf_warning_or_error) | |
653e5405 | 1565 | : NULL_TREE; |
96ec9e30 | 1566 | |
64ec1ad6 | 1567 | case COMPLEX_TYPE: |
96ec9e30 | 1568 | case VECTOR_TYPE: |
64ec1ad6 | 1569 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1570 | return NULL_TREE; |
1571 | switch (TREE_CODE (TREE_TYPE (basetype))) | |
1572 | { | |
1573 | case INTEGER_TYPE: | |
1574 | case BOOLEAN_TYPE: | |
1575 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1576 | case ENUMERAL_TYPE: | |
1577 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1578 | case REAL_TYPE: | |
1579 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1580 | default: | |
1581 | return NULL_TREE; | |
1582 | } | |
1583 | ||
bdd152ce | 1584 | default: |
1585 | return NULL_TREE; | |
1586 | } | |
1587 | ||
1588 | /* The code for conversions from class type is currently only used for | |
1589 | delete expressions. Other expressions are handled by build_new_op. */ | |
a5f2d620 | 1590 | if (!complete_type_or_maybe_complain (basetype, expr, complain)) |
f8182e08 | 1591 | return error_mark_node; |
1592 | if (!TYPE_HAS_CONVERSION (basetype)) | |
bdd152ce | 1593 | return NULL_TREE; |
1594 | ||
9960d752 | 1595 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) |
bdd152ce | 1596 | { |
1597 | int win = 0; | |
1598 | tree candidate; | |
1599 | tree cand = TREE_VALUE (conv); | |
c1ca2f12 | 1600 | cand = OVL_CURRENT (cand); |
bdd152ce | 1601 | |
1602 | if (winner && winner == cand) | |
1603 | continue; | |
1604 | ||
cf7aa2e5 | 1605 | if (DECL_NONCONVERTING_P (cand)) |
1606 | continue; | |
1607 | ||
ef4534a3 | 1608 | candidate = non_reference (TREE_TYPE (TREE_TYPE (cand))); |
bdd152ce | 1609 | |
1610 | switch (TREE_CODE (candidate)) | |
1611 | { | |
1612 | case BOOLEAN_TYPE: | |
1613 | case INTEGER_TYPE: | |
1614 | win = (desires & WANT_INT); break; | |
1615 | case ENUMERAL_TYPE: | |
1616 | win = (desires & WANT_ENUM); break; | |
1617 | case REAL_TYPE: | |
1618 | win = (desires & WANT_FLOAT); break; | |
1619 | case POINTER_TYPE: | |
1620 | win = (desires & WANT_POINTER); break; | |
1621 | ||
64ec1ad6 | 1622 | case COMPLEX_TYPE: |
96ec9e30 | 1623 | case VECTOR_TYPE: |
64ec1ad6 | 1624 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1625 | break; |
1626 | switch (TREE_CODE (TREE_TYPE (candidate))) | |
1627 | { | |
1628 | case BOOLEAN_TYPE: | |
1629 | case INTEGER_TYPE: | |
1630 | win = (desires & WANT_INT); break; | |
1631 | case ENUMERAL_TYPE: | |
1632 | win = (desires & WANT_ENUM); break; | |
1633 | case REAL_TYPE: | |
1634 | win = (desires & WANT_FLOAT); break; | |
1635 | default: | |
1636 | break; | |
1637 | } | |
1638 | break; | |
1639 | ||
bdd152ce | 1640 | default: |
9c4c1195 | 1641 | /* A wildcard could be instantiated to match any desired |
1642 | type, but we can't deduce the template argument. */ | |
1643 | if (WILDCARD_TYPE_P (candidate)) | |
1644 | win = true; | |
bdd152ce | 1645 | break; |
1646 | } | |
1647 | ||
1648 | if (win) | |
1649 | { | |
9c4c1195 | 1650 | if (TREE_CODE (cand) == TEMPLATE_DECL) |
1651 | { | |
1652 | if (complain) | |
1653 | error ("default type conversion can't deduce template" | |
1654 | " argument for %qD", cand); | |
1655 | return error_mark_node; | |
1656 | } | |
1657 | ||
bdd152ce | 1658 | if (winner) |
1659 | { | |
609c541f | 1660 | tree winner_type |
1661 | = non_reference (TREE_TYPE (TREE_TYPE (winner))); | |
1662 | ||
1663 | if (!same_type_ignoring_top_level_qualifiers_p (winner_type, | |
1664 | candidate)) | |
bdd152ce | 1665 | { |
609c541f | 1666 | if (complain) |
1667 | { | |
1668 | error ("ambiguous default type conversion from %qT", | |
1669 | basetype); | |
392214f6 | 1670 | inform (input_location, |
1671 | " candidate conversions include %qD and %qD", | |
1672 | winner, cand); | |
609c541f | 1673 | } |
1674 | return error_mark_node; | |
bdd152ce | 1675 | } |
bdd152ce | 1676 | } |
609c541f | 1677 | |
1678 | winner = cand; | |
bdd152ce | 1679 | } |
1680 | } | |
1e66592c | 1681 | |
bdd152ce | 1682 | if (winner) |
1683 | { | |
ef4534a3 | 1684 | tree type = non_reference (TREE_TYPE (TREE_TYPE (winner))); |
66bbeb85 | 1685 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL, |
1686 | tf_warning_or_error); | |
471086d6 | 1687 | } |
1e66592c | 1688 | |
985e9ee0 | 1689 | return NULL_TREE; |
471086d6 | 1690 | } |
bc3887cf | 1691 | |
96624a9e | 1692 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1693 | ||
bc3887cf | 1694 | tree |
35771a9a | 1695 | type_promotes_to (tree type) |
bc3887cf | 1696 | { |
2b3c93a3 | 1697 | tree promoted_type; |
1698 | ||
ce28ee2e | 1699 | if (type == error_mark_node) |
1700 | return error_mark_node; | |
1701 | ||
bc3887cf | 1702 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1703 | |
2b3c93a3 | 1704 | /* Check for promotions of target-defined types first. */ |
1705 | promoted_type = targetm.promoted_type (type); | |
1706 | if (promoted_type) | |
1707 | return promoted_type; | |
1708 | ||
bb0726a1 | 1709 | /* bool always promotes to int (not unsigned), even if it's the same |
1710 | size. */ | |
9e1a8234 | 1711 | if (TREE_CODE (type) == BOOLEAN_TYPE) |
bb0726a1 | 1712 | type = integer_type_node; |
1713 | ||
1714 | /* Normally convert enums to int, but convert wide enums to something | |
74b777e5 | 1715 | wider. Scoped enums don't promote, but pretend they do for backward |
1716 | ABI bug compatibility wrt varargs. */ | |
bb0726a1 | 1717 | else if (TREE_CODE (type) == ENUMERAL_TYPE |
924bbf02 | 1718 | || type == char16_type_node |
1719 | || type == char32_type_node | |
bb0726a1 | 1720 | || type == wchar_type_node) |
6c9497b1 | 1721 | { |
1722 | int precision = MAX (TYPE_PRECISION (type), | |
1723 | TYPE_PRECISION (integer_type_node)); | |
771d21fa | 1724 | tree totype = c_common_type_for_size (precision, 0); |
74b777e5 | 1725 | tree prom = type; |
1726 | if (TREE_CODE (prom) == ENUMERAL_TYPE) | |
1727 | prom = ENUM_UNDERLYING_TYPE (prom); | |
1728 | if (TYPE_UNSIGNED (prom) | |
1729 | && ! int_fits_type_p (TYPE_MAX_VALUE (prom), totype)) | |
1730 | prom = c_common_type_for_size (precision, 1); | |
1731 | else | |
1732 | prom = totype; | |
72fc0f64 | 1733 | if (SCOPED_ENUM_P (type)) |
74b777e5 | 1734 | { |
1735 | if (abi_version_crosses (6) | |
1736 | && TYPE_MODE (prom) != TYPE_MODE (type)) | |
1737 | warning (OPT_Wabi, "scoped enum %qT passed through ... as " | |
1738 | "%qT before -fabi-version=6, %qT after", | |
1739 | type, prom, ENUM_UNDERLYING_TYPE (type)); | |
1740 | if (!abi_version_at_least (6)) | |
1741 | type = prom; | |
1742 | } | |
6c9497b1 | 1743 | else |
74b777e5 | 1744 | type = prom; |
6c9497b1 | 1745 | } |
d7aeef06 | 1746 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1747 | { |
d0acef9e | 1748 | /* Retain unsignedness if really not getting bigger. */ |
78a8ed03 | 1749 | if (TYPE_UNSIGNED (type) |
d0acef9e | 1750 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1751 | type = unsigned_type_node; |
1752 | else | |
1753 | type = integer_type_node; | |
1754 | } | |
1755 | else if (type == float_type_node) | |
1756 | type = double_type_node; | |
9031d10b | 1757 | |
a681799d | 1758 | return type; |
bc3887cf | 1759 | } |
668ae905 | 1760 | |
668ae905 | 1761 | /* The routines below this point are carefully written to conform to |
1762 | the standard. They use the same terminology, and follow the rules | |
1763 | closely. Although they are used only in pt.c at the moment, they | |
1764 | should presumably be used everywhere in the future. */ | |
1765 | ||
1146f179 | 1766 | /* Attempt to perform qualification conversions on EXPR to convert it |
1767 | to TYPE. Return the resulting expression, or error_mark_node if | |
1768 | the conversion was impossible. */ | |
1769 | ||
9031d10b | 1770 | tree |
35771a9a | 1771 | perform_qualification_conversions (tree type, tree expr) |
668ae905 | 1772 | { |
1bc16cab | 1773 | tree expr_type; |
1774 | ||
1775 | expr_type = TREE_TYPE (expr); | |
1776 | ||
3b087710 | 1777 | if (same_type_p (type, expr_type)) |
1778 | return expr; | |
1779 | else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type) | |
1780 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type))) | |
1bc16cab | 1781 | return build_nop (type, expr); |
05765a91 | 1782 | else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (expr_type) |
1bc16cab | 1783 | && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type), |
1784 | TYPE_PTRMEM_CLASS_TYPE (expr_type)) | |
1785 | && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type), | |
1786 | TYPE_PTRMEM_POINTED_TO_TYPE (expr_type))) | |
1787 | return build_nop (type, expr); | |
1146f179 | 1788 | else |
1789 | return error_mark_node; | |
668ae905 | 1790 | } |
6d02e6b2 | 1791 | |
1792 | /* True iff T is a transaction-safe function type. */ | |
1793 | ||
1794 | bool | |
1795 | tx_safe_fn_type_p (tree t) | |
1796 | { | |
1797 | if (TREE_CODE (t) != FUNCTION_TYPE | |
1798 | && TREE_CODE (t) != METHOD_TYPE) | |
1799 | return false; | |
1800 | return !!lookup_attribute ("transaction_safe", TYPE_ATTRIBUTES (t)); | |
1801 | } | |
1802 | ||
1803 | /* Return the transaction-unsafe variant of transaction-safe function type | |
1804 | T. */ | |
1805 | ||
1806 | tree | |
1807 | tx_unsafe_fn_variant (tree t) | |
1808 | { | |
1809 | gcc_assert (tx_safe_fn_type_p (t)); | |
1810 | tree attrs = remove_attribute ("transaction_safe", | |
1811 | TYPE_ATTRIBUTES (t)); | |
1812 | return cp_build_type_attribute_variant (t, attrs); | |
1813 | } | |
1814 | ||
1815 | /* Return true iff FROM can convert to TO by a transaction-safety | |
1816 | conversion. */ | |
1817 | ||
1818 | bool | |
1819 | can_convert_tx_safety (tree to, tree from) | |
1820 | { | |
1821 | return (flag_tm && tx_safe_fn_type_p (from) | |
1822 | && same_type_p (to, tx_unsafe_fn_variant (from))); | |
1823 | } |