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471086d6 | 1 | /* Language-level data type conversion for GNU C++. |
711789cc | 2 | Copyright (C) 1987-2013 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" |
30 | #include "tm.h" | |
471086d6 | 31 | #include "tree.h" |
32 | #include "flags.h" | |
33 | #include "cp-tree.h" | |
ca82e026 | 34 | #include "intl.h" |
471086d6 | 35 | #include "convert.h" |
2e8226f7 | 36 | #include "decl.h" |
7a979707 | 37 | #include "target.h" |
96624a9e | 38 | |
c4698a21 | 39 | static tree cp_convert_to_pointer (tree, tree, tsubst_flags_t); |
40 | static tree convert_to_pointer_force (tree, tree, tsubst_flags_t); | |
ef9571e5 | 41 | static tree build_type_conversion (tree, tree); |
c4698a21 | 42 | static tree build_up_reference (tree, tree, int, tree, tsubst_flags_t); |
61f69bc9 | 43 | static void warn_ref_binding (location_t, 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), | |
653e5405 | 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 | |
e5ead12a | 72 | else try C-style pointer conversion. */ |
96624a9e | 73 | |
471086d6 | 74 | static tree |
c4698a21 | 75 | cp_convert_to_pointer (tree type, tree expr, tsubst_flags_t complain) |
471086d6 | 76 | { |
cd16867a | 77 | tree intype = TREE_TYPE (expr); |
78 | enum tree_code form; | |
f82eeb87 | 79 | tree rval; |
61f69bc9 | 80 | location_t loc = EXPR_LOC_OR_HERE (expr); |
81 | ||
8bf328bf | 82 | if (intype == error_mark_node) |
83 | return error_mark_node; | |
74002e1d | 84 | |
95397ff9 | 85 | if (MAYBE_CLASS_TYPE_P (intype)) |
96624a9e | 86 | { |
96624a9e | 87 | intype = complete_type (intype); |
4b72716d | 88 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 89 | { |
c4698a21 | 90 | if (complain & tf_error) |
91 | error_at (loc, "can%'t convert from incomplete type %qT to %qT", | |
92 | intype, type); | |
96624a9e | 93 | return error_mark_node; |
94 | } | |
95 | ||
8999978b | 96 | rval = build_type_conversion (type, expr); |
96624a9e | 97 | if (rval) |
98 | { | |
c4698a21 | 99 | if ((complain & tf_error) |
100 | && rval == error_mark_node) | |
61f69bc9 | 101 | error_at (loc, "conversion of %qE from %qT to %qT is ambiguous", |
102 | expr, intype, type); | |
96624a9e | 103 | return rval; |
104 | } | |
105 | } | |
106 | ||
860740a7 | 107 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 108 | if (TREE_CODE (type) == POINTER_TYPE |
109 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
e3cfe3ce | 110 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 111 | { |
6ab399e8 | 112 | if (TYPE_PTRMEMFUNC_P (intype) |
113 | || TREE_CODE (intype) == METHOD_TYPE) | |
c4698a21 | 114 | return convert_member_func_to_ptr (type, expr, complain); |
a63bc44c | 115 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) |
116 | return build_nop (type, expr); | |
38281c46 | 117 | intype = TREE_TYPE (expr); |
118 | } | |
119 | ||
311e42bc | 120 | if (expr == error_mark_node) |
121 | return error_mark_node; | |
122 | ||
74002e1d | 123 | form = TREE_CODE (intype); |
124 | ||
2b77484d | 125 | if (POINTER_TYPE_P (intype)) |
471086d6 | 126 | { |
127 | intype = TYPE_MAIN_VARIANT (intype); | |
128 | ||
129 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 130 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 131 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
95397ff9 | 132 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
133 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
4a2680fc | 134 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
471086d6 | 135 | { |
136 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 137 | tree binfo; |
8999978b | 138 | tree intype_class; |
139 | tree type_class; | |
140 | bool same_p; | |
4a2680fc | 141 | |
8999978b | 142 | intype_class = TREE_TYPE (intype); |
143 | type_class = TREE_TYPE (type); | |
144 | ||
9031d10b | 145 | same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class), |
8999978b | 146 | TYPE_MAIN_VARIANT (type_class)); |
147 | binfo = NULL_TREE; | |
c0af329c | 148 | /* Try derived to base conversion. */ |
8999978b | 149 | if (!same_p) |
ae260dcc | 150 | binfo = lookup_base (intype_class, type_class, ba_check, |
151 | NULL, complain); | |
8999978b | 152 | if (!same_p && !binfo) |
471086d6 | 153 | { |
c0af329c | 154 | /* Try base to derived conversion. */ |
ae260dcc | 155 | binfo = lookup_base (type_class, intype_class, ba_check, |
156 | NULL, complain); | |
471086d6 | 157 | code = MINUS_EXPR; |
158 | } | |
4a2680fc | 159 | if (binfo == error_mark_node) |
160 | return error_mark_node; | |
8999978b | 161 | if (binfo || same_p) |
471086d6 | 162 | { |
8999978b | 163 | if (binfo) |
c4698a21 | 164 | expr = build_base_path (code, expr, binfo, 0, complain); |
c0af329c | 165 | /* Add any qualifier conversions. */ |
8999978b | 166 | return build_nop (type, expr); |
471086d6 | 167 | } |
168 | } | |
471086d6 | 169 | |
1bc16cab | 170 | if (TYPE_PTRMEMFUNC_P (type)) |
bea7d742 | 171 | { |
c4698a21 | 172 | if (complain & tf_error) |
173 | error_at (loc, "cannot convert %qE from type %qT to type %qT", | |
174 | expr, intype, type); | |
1bc16cab | 175 | return error_mark_node; |
176 | } | |
a17aefa2 | 177 | |
1bc16cab | 178 | return build_nop (type, expr); |
179 | } | |
05765a91 | 180 | else if ((TYPE_PTRDATAMEM_P (type) && TYPE_PTRDATAMEM_P (intype)) |
e5ead12a | 181 | || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) |
182 | return convert_ptrmem (type, expr, /*allow_inverse_p=*/false, | |
c4698a21 | 183 | /*c_cast_p=*/false, complain); |
2b77484d | 184 | else if (TYPE_PTRMEMFUNC_P (intype)) |
185 | { | |
a63bc44c | 186 | if (!warn_pmf2ptr) |
187 | { | |
188 | if (TREE_CODE (expr) == PTRMEM_CST) | |
c4698a21 | 189 | return cp_convert_to_pointer (type, PTRMEM_CST_MEMBER (expr), |
190 | complain); | |
a63bc44c | 191 | else if (TREE_CODE (expr) == OFFSET_REF) |
192 | { | |
193 | tree object = TREE_OPERAND (expr, 0); | |
194 | return get_member_function_from_ptrfunc (&object, | |
4405c1ad | 195 | TREE_OPERAND (expr, 1), |
c4698a21 | 196 | complain); |
a63bc44c | 197 | } |
198 | } | |
61f69bc9 | 199 | error_at (loc, "cannot convert %qE from type %qT to type %qT", |
200 | expr, intype, type); | |
2b77484d | 201 | return error_mark_node; |
202 | } | |
471086d6 | 203 | |
ef434176 | 204 | if (null_ptr_cst_p (expr)) |
471086d6 | 205 | { |
49858f84 | 206 | if (complain & tf_warning) |
207 | maybe_warn_zero_as_null_pointer_constant (expr, loc); | |
8fe701f5 | 208 | |
2b77484d | 209 | if (TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 210 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
c4698a21 | 211 | /*c_cast_p=*/false, complain); |
ad63a0fc | 212 | |
7ba2f86f | 213 | /* A NULL pointer-to-data-member is represented by -1, not by |
214 | zero. */ | |
215 | tree val = (TYPE_PTRDATAMEM_P (type) | |
216 | ? build_int_cst_type (type, -1) | |
217 | : build_int_cst (type, 0)); | |
218 | ||
219 | return (TREE_SIDE_EFFECTS (expr) | |
220 | ? build2 (COMPOUND_EXPR, type, expr, val) : val); | |
471086d6 | 221 | } |
05765a91 | 222 | else if (TYPE_PTRMEM_P (type) && INTEGRAL_CODE_P (form)) |
de1f960a | 223 | { |
c4698a21 | 224 | if (complain & tf_error) |
225 | error_at (loc, "invalid conversion from %qT to %qT", intype, type); | |
de1f960a | 226 | return error_mark_node; |
227 | } | |
471086d6 | 228 | |
bb0726a1 | 229 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 230 | { |
c5aa1e92 | 231 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 232 | return build1 (CONVERT_EXPR, type, expr); |
c4698a21 | 233 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr, |
234 | complain); | |
092b1d6f | 235 | /* Modes may be different but sizes should be the same. There |
236 | is supposed to be some integral type that is the same width | |
237 | as a pointer. */ | |
238 | gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
239 | == GET_MODE_SIZE (TYPE_MODE (type))); | |
9031d10b | 240 | |
471086d6 | 241 | return convert_to_pointer (type, expr); |
242 | } | |
243 | ||
cc4d0855 | 244 | if (type_unknown_p (expr)) |
c4698a21 | 245 | return instantiate_type (type, expr, complain); |
cc4d0855 | 246 | |
c4698a21 | 247 | if (complain & tf_error) |
248 | error_at (loc, "cannot convert %qE from type %qT to type %qT", | |
249 | expr, intype, type); | |
471086d6 | 250 | return error_mark_node; |
251 | } | |
252 | ||
253 | /* Like convert, except permit conversions to take place which | |
254 | are not normally allowed due to access restrictions | |
255 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 256 | |
471086d6 | 257 | static tree |
c4698a21 | 258 | convert_to_pointer_force (tree type, tree expr, tsubst_flags_t complain) |
471086d6 | 259 | { |
cd16867a | 260 | tree intype = TREE_TYPE (expr); |
261 | enum tree_code form = TREE_CODE (intype); | |
9031d10b | 262 | |
471086d6 | 263 | if (form == POINTER_TYPE) |
264 | { | |
265 | intype = TYPE_MAIN_VARIANT (intype); | |
266 | ||
267 | if (TYPE_MAIN_VARIANT (type) != intype | |
268 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
95397ff9 | 269 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
270 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
471086d6 | 271 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
272 | { | |
273 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 274 | tree binfo; |
275 | ||
276 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
ae260dcc | 277 | ba_unique, NULL, complain); |
4a2680fc | 278 | if (!binfo) |
471086d6 | 279 | { |
4a2680fc | 280 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
ae260dcc | 281 | ba_unique, NULL, complain); |
4a2680fc | 282 | code = MINUS_EXPR; |
471086d6 | 283 | } |
4a2680fc | 284 | if (binfo == error_mark_node) |
285 | return error_mark_node; | |
286 | if (binfo) | |
471086d6 | 287 | { |
c4698a21 | 288 | expr = build_base_path (code, expr, binfo, 0, complain); |
653e5405 | 289 | if (expr == error_mark_node) |
290 | return error_mark_node; | |
c0af329c | 291 | /* Add any qualifier conversions. */ |
4a2680fc | 292 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
293 | TREE_TYPE (type))) | |
8999978b | 294 | expr = build_nop (type, expr); |
4a2680fc | 295 | return expr; |
471086d6 | 296 | } |
471086d6 | 297 | } |
471086d6 | 298 | } |
299 | ||
c4698a21 | 300 | return cp_convert_to_pointer (type, expr, complain); |
471086d6 | 301 | } |
302 | ||
303 | /* We are passing something to a function which requires a reference. | |
304 | The type we are interested in is in TYPE. The initial | |
305 | value we have to begin with is in ARG. | |
306 | ||
307 | FLAGS controls how we manage access checking. | |
ca106ab1 | 308 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
309 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 310 | |
471086d6 | 311 | static tree |
c4698a21 | 312 | build_up_reference (tree type, tree arg, int flags, tree decl, |
313 | tsubst_flags_t complain) | |
471086d6 | 314 | { |
c76251c1 | 315 | tree rval; |
0543e7a9 | 316 | tree argtype = TREE_TYPE (arg); |
471086d6 | 317 | tree target_type = TREE_TYPE (type); |
471086d6 | 318 | |
b4df430b | 319 | gcc_assert (TREE_CODE (type) == REFERENCE_TYPE); |
471086d6 | 320 | |
c76251c1 | 321 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 322 | { |
ca106ab1 | 323 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
324 | here because it needs to live as long as DECL. */ | |
c76251c1 | 325 | tree targ = arg; |
ca106ab1 | 326 | |
5ab1aaca | 327 | arg = make_temporary_var_for_ref_to_temp (decl, target_type); |
c23ebfdd | 328 | |
329 | /* Process the initializer for the declaration. */ | |
38281c46 | 330 | DECL_INITIAL (arg) = targ; |
d91303a6 | 331 | cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE, |
011310f7 | 332 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 333 | } |
c76251c1 | 334 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
44189c16 | 335 | return get_target_expr_sfinae (arg, complain); |
1ad432f2 | 336 | |
ca106ab1 | 337 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 338 | address, transform all occurrences of the register, into a memory |
339 | reference we could win better. */ | |
44189c16 | 340 | rval = cp_build_addr_expr (arg, complain); |
15e55420 | 341 | if (rval == error_mark_node) |
342 | return error_mark_node; | |
343 | ||
6686e84d | 344 | if ((flags & LOOKUP_PROTECT) |
345 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
95397ff9 | 346 | && MAYBE_CLASS_TYPE_P (argtype) |
347 | && MAYBE_CLASS_TYPE_P (target_type)) | |
6686e84d | 348 | { |
7e6960e0 | 349 | /* We go through lookup_base for the access control. */ |
ae260dcc | 350 | tree binfo = lookup_base (argtype, target_type, ba_check, |
351 | NULL, complain); | |
6686e84d | 352 | if (binfo == error_mark_node) |
353 | return error_mark_node; | |
354 | if (binfo == NULL_TREE) | |
355 | return error_not_base_type (target_type, argtype); | |
c4698a21 | 356 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1, complain); |
6686e84d | 357 | } |
c76251c1 | 358 | else |
359 | rval | |
c4698a21 | 360 | = convert_to_pointer_force (build_pointer_type (target_type), |
361 | rval, complain); | |
8999978b | 362 | return build_nop (type, rval); |
471086d6 | 363 | } |
364 | ||
519ba62c | 365 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
366 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
367 | for diagnostics. | |
9031d10b | 368 | |
519ba62c | 369 | [dcl.init.ref] says that if an rvalue is used to |
370 | initialize a reference, then the reference must be to a | |
371 | non-volatile const type. */ | |
372 | ||
373 | static void | |
61f69bc9 | 374 | warn_ref_binding (location_t loc, tree reftype, tree intype, tree decl) |
519ba62c | 375 | { |
376 | tree ttl = TREE_TYPE (reftype); | |
9031d10b | 377 | |
519ba62c | 378 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) |
379 | { | |
380 | const char *msg; | |
381 | ||
382 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
ca82e026 | 383 | msg = G_("initialization of volatile reference type %q#T from " |
384 | "rvalue of type %qT"); | |
519ba62c | 385 | else if (CP_TYPE_VOLATILE_P (ttl)) |
ca82e026 | 386 | msg = G_("conversion to volatile reference type %q#T " |
387 | "from rvalue of type %qT"); | |
519ba62c | 388 | else if (decl) |
ca82e026 | 389 | msg = G_("initialization of non-const reference type %q#T from " |
390 | "rvalue of type %qT"); | |
519ba62c | 391 | else |
ca82e026 | 392 | msg = G_("conversion to non-const reference type %q#T from " |
393 | "rvalue of type %qT"); | |
519ba62c | 394 | |
61f69bc9 | 395 | permerror (loc, msg, reftype, intype); |
519ba62c | 396 | } |
397 | } | |
398 | ||
471086d6 | 399 | /* For C++: Only need to do one-level references, but cannot |
400 | get tripped up on signed/unsigned differences. | |
401 | ||
d81e00a4 | 402 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
403 | initialized. It can be error_mark_node if we don't know the _DECL but | |
404 | we know it's an initialization. */ | |
471086d6 | 405 | |
471086d6 | 406 | tree |
35771a9a | 407 | convert_to_reference (tree reftype, tree expr, int convtype, |
c4698a21 | 408 | int flags, tree decl, tsubst_flags_t complain) |
471086d6 | 409 | { |
cd16867a | 410 | tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); |
411 | tree intype; | |
471086d6 | 412 | tree rval = NULL_TREE; |
1a3f833b | 413 | tree rval_as_conversion = NULL_TREE; |
1bc16cab | 414 | bool can_convert_intype_to_type; |
61f69bc9 | 415 | location_t loc = EXPR_LOC_OR_HERE (expr); |
1a3f833b | 416 | |
9031d10b | 417 | if (TREE_CODE (type) == FUNCTION_TYPE |
d32df6a6 | 418 | && TREE_TYPE (expr) == unknown_type_node) |
66bbeb85 | 419 | expr = instantiate_type (type, expr, complain); |
0a3b29ad | 420 | |
421 | if (expr == error_mark_node) | |
422 | return error_mark_node; | |
423 | ||
424 | intype = TREE_TYPE (expr); | |
cc4d0855 | 425 | |
b4df430b | 426 | gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE); |
ab12ed55 | 427 | gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE); |
471086d6 | 428 | |
471086d6 | 429 | intype = TYPE_MAIN_VARIANT (intype); |
430 | ||
66bbeb85 | 431 | can_convert_intype_to_type = can_convert (type, intype, complain); |
432 | ||
1bc16cab | 433 | if (!can_convert_intype_to_type |
95397ff9 | 434 | && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype) |
1a3f833b | 435 | && ! (flags & LOOKUP_NO_CONVERSION)) |
436 | { | |
437 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
438 | ||
0a4be248 | 439 | rval_as_conversion |
8999978b | 440 | = build_type_conversion (reftype, expr); |
1a3f833b | 441 | |
442 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
443 | && real_lvalue_p (rval_as_conversion)) | |
444 | { | |
445 | expr = rval_as_conversion; | |
446 | rval_as_conversion = NULL_TREE; | |
447 | intype = type; | |
1bc16cab | 448 | can_convert_intype_to_type = 1; |
1a3f833b | 449 | } |
450 | } | |
451 | ||
66bbeb85 | 452 | if (((convtype & CONV_STATIC) && can_convert (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 | |
c4698a21 | 459 | if ((complain & tf_warning) |
460 | && ! real_lvalue_p (expr)) | |
461 | warn_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) |
486 | && TREE_CODE (intype) == POINTER_TYPE | |
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; | |
c4698a21 | 505 | if (complain & tf_warning) |
506 | warn_ref_binding (loc, reftype, intype, decl); | |
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. */ | |
583 | expr = build_int_cst_wide (TREE_TYPE (expr), | |
584 | TREE_INT_CST_LOW (expr), | |
585 | TREE_INT_CST_HIGH (expr)); | |
586 | } | |
587 | return expr; | |
588 | } | |
589 | ||
590 | /* Fold away simple conversions, but make sure TREE_OVERFLOW is set | |
591 | properly. */ | |
f5220369 | 592 | |
593 | tree | |
594 | cp_fold_convert (tree type, tree expr) | |
595 | { | |
a1f05651 | 596 | tree conv = fold_convert (type, expr); |
597 | conv = ignore_overflows (conv, expr); | |
598 | return conv; | |
f5220369 | 599 | } |
600 | ||
c4a8ac95 | 601 | /* C++ conversions, preference to static cast conversions. */ |
602 | ||
603 | tree | |
c4698a21 | 604 | cp_convert (tree type, tree expr, tsubst_flags_t complain) |
c4a8ac95 | 605 | { |
c4698a21 | 606 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL, complain); |
c4a8ac95 | 607 | } |
608 | ||
59dd8856 | 609 | /* C++ equivalent of convert_and_check but using cp_convert as the |
610 | conversion function. | |
611 | ||
612 | Convert EXPR to TYPE, warning about conversion problems with constants. | |
613 | Invoke this function on every expression that is converted implicitly, | |
614 | i.e. because of language rules and not because of an explicit cast. */ | |
615 | ||
616 | tree | |
c4698a21 | 617 | cp_convert_and_check (tree type, tree expr, tsubst_flags_t complain) |
59dd8856 | 618 | { |
619 | tree result; | |
620 | ||
621 | if (TREE_TYPE (expr) == type) | |
622 | return expr; | |
623 | ||
c4698a21 | 624 | result = cp_convert (type, expr, complain); |
59dd8856 | 625 | |
c4698a21 | 626 | if ((complain & tf_warning) |
627 | && c_inhibit_evaluation_warnings == 0 | |
48d94ede | 628 | && !TREE_OVERFLOW_P (expr) |
629 | && result != error_mark_node) | |
59dd8856 | 630 | warnings_for_convert_and_check (type, expr, result); |
631 | ||
632 | return result; | |
633 | } | |
634 | ||
b248d3f7 | 635 | /* Conversion... |
636 | ||
637 | FLAGS indicates how we should behave. */ | |
638 | ||
471086d6 | 639 | tree |
c4698a21 | 640 | ocp_convert (tree type, tree expr, int convtype, int flags, |
641 | tsubst_flags_t complain) | |
471086d6 | 642 | { |
cd16867a | 643 | tree e = expr; |
644 | enum tree_code code = TREE_CODE (type); | |
7a979707 | 645 | const char *invalid_conv_diag; |
2b3c93a3 | 646 | tree e1; |
61f69bc9 | 647 | location_t loc = EXPR_LOC_OR_HERE (expr); |
471086d6 | 648 | |
1bc16cab | 649 | if (error_operand_p (e) || type == error_mark_node) |
471086d6 | 650 | return error_mark_node; |
d81e00a4 | 651 | |
5b592939 | 652 | complete_type (type); |
653 | complete_type (TREE_TYPE (expr)); | |
654 | ||
7a979707 | 655 | if ((invalid_conv_diag |
656 | = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
657 | { | |
c4698a21 | 658 | if (complain & tf_error) |
659 | error (invalid_conv_diag); | |
7a979707 | 660 | return error_mark_node; |
661 | } | |
662 | ||
ce984e5e | 663 | /* FIXME remove when moving to c_fully_fold model. */ |
664 | /* FIXME do we still need this test? */ | |
665 | if (!CLASS_TYPE_P (type)) | |
666 | e = integral_constant_value (e); | |
7a00f939 | 667 | if (error_operand_p (e)) |
668 | return error_mark_node; | |
7745052b | 669 | |
95397ff9 | 670 | if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP)) |
1a3f833b | 671 | /* We need a new temporary; don't take this shortcut. */; |
930e8175 | 672 | else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e))) |
ca23ec64 | 673 | { |
daf9ff67 | 674 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 675 | /* The call to fold will not always remove the NOP_EXPR as |
676 | might be expected, since if one of the types is a typedef; | |
755edffd | 677 | the comparison in fold is just equality of pointers, not a |
a09db423 | 678 | call to comptypes. We don't call fold in this case because |
f699c174 | 679 | that can result in infinite recursion; fold will call |
680 | convert, which will call ocp_convert, etc. */ | |
681 | return e; | |
372e0e29 | 682 | /* For complex data types, we need to perform componentwise |
653e5405 | 683 | conversion. */ |
372e0e29 | 684 | else if (TREE_CODE (type) == COMPLEX_TYPE) |
653e5405 | 685 | return fold_if_not_in_template (convert_to_complex (type, e)); |
31631c53 | 686 | else if (TREE_CODE (type) == VECTOR_TYPE) |
687 | return fold_if_not_in_template (convert_to_vector (type, e)); | |
bdb2219e | 688 | else if (TREE_CODE (e) == TARGET_EXPR) |
689 | { | |
690 | /* Don't build a NOP_EXPR of class type. Instead, change the | |
930e8175 | 691 | type of the temporary. */ |
bdb2219e | 692 | TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type; |
693 | return e; | |
694 | } | |
ca23ec64 | 695 | else |
092b1d6f | 696 | { |
697 | /* We shouldn't be treating objects of ADDRESSABLE type as | |
698 | rvalues. */ | |
699 | gcc_assert (!TREE_ADDRESSABLE (type)); | |
5d7ed6c7 | 700 | return fold_if_not_in_template (build_nop (type, e)); |
092b1d6f | 701 | } |
ca23ec64 | 702 | } |
703 | ||
2b3c93a3 | 704 | e1 = targetm.convert_to_type (type, e); |
705 | if (e1) | |
706 | return e1; | |
707 | ||
d81e00a4 | 708 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 709 | { |
c4698a21 | 710 | e = convert_to_void (e, ICV_CAST, complain); |
aeef2be5 | 711 | return e; |
95b2ac55 | 712 | } |
d81e00a4 | 713 | |
bb0726a1 | 714 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 715 | { |
617abf06 | 716 | tree intype = TREE_TYPE (e); |
a1f05651 | 717 | tree converted; |
384590d4 | 718 | |
719 | if (TREE_CODE (type) == ENUMERAL_TYPE) | |
720 | { | |
721 | /* enum = enum, enum = int, enum = float, (enum)pointer are all | |
722 | errors. */ | |
723 | if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype) | |
653e5405 | 724 | || TREE_CODE (intype) == REAL_TYPE) |
b312a686 | 725 | && ! (convtype & CONV_STATIC)) |
384590d4 | 726 | || TREE_CODE (intype) == POINTER_TYPE) |
727 | { | |
c4698a21 | 728 | if (complain & tf_error) |
61f69bc9 | 729 | permerror (loc, "conversion from %q#T to %q#T", intype, type); |
c4698a21 | 730 | else |
384590d4 | 731 | return error_mark_node; |
732 | } | |
733 | ||
734 | /* [expr.static.cast] | |
735 | ||
736 | 8. A value of integral or enumeration type can be explicitly | |
737 | converted to an enumeration type. The value is unchanged if | |
738 | the original value is within the range of the enumeration | |
739 | values. Otherwise, the resulting enumeration value is | |
740 | unspecified. */ | |
c4698a21 | 741 | if ((complain & tf_warning) |
c28ddc97 | 742 | && TREE_CODE (e) == INTEGER_CST |
743 | && !int_fits_type_p (e, ENUM_UNDERLYING_TYPE (type))) | |
61f69bc9 | 744 | warning_at (loc, OPT_Wconversion, |
745 | "the result of the conversion is unspecified because " | |
746 | "%qE is outside the range of type %qT", | |
747 | expr, type); | |
471086d6 | 748 | } |
95397ff9 | 749 | if (MAYBE_CLASS_TYPE_P (intype)) |
471086d6 | 750 | { |
751 | tree rval; | |
8999978b | 752 | rval = build_type_conversion (type, e); |
6495357a | 753 | if (rval) |
754 | return rval; | |
c4698a21 | 755 | if (complain & tf_error) |
61f69bc9 | 756 | error_at (loc, "%q#T used where a %qT was expected", intype, type); |
471086d6 | 757 | return error_mark_node; |
758 | } | |
bb0726a1 | 759 | if (code == BOOLEAN_TYPE) |
f8913d47 | 760 | { |
61f69bc9 | 761 | if (TREE_CODE (intype) == VOID_TYPE) |
762 | { | |
c4698a21 | 763 | if (complain & tf_error) |
764 | error_at (loc, | |
765 | "could not convert %qE from %<void%> to %<bool%>", | |
766 | expr); | |
61f69bc9 | 767 | return error_mark_node; |
768 | } | |
769 | ||
f8913d47 | 770 | /* We can't implicitly convert a scoped enum to bool, so convert |
771 | to the underlying type first. */ | |
772 | if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC)) | |
172fff7b | 773 | e = build_nop (ENUM_UNDERLYING_TYPE (intype), e); |
f8913d47 | 774 | return cp_truthvalue_conversion (e); |
775 | } | |
ce871053 | 776 | |
a1f05651 | 777 | converted = fold_if_not_in_template (convert_to_integer (type, e)); |
778 | ||
779 | /* Ignore any integer overflow caused by the conversion. */ | |
780 | return ignore_overflows (converted, e); | |
471086d6 | 781 | } |
c7ca48ea | 782 | if (NULLPTR_TYPE_P (type) && e && null_ptr_cst_p (e)) |
49858f84 | 783 | { |
784 | if (complain & tf_warning) | |
785 | maybe_warn_zero_as_null_pointer_constant (e, loc); | |
786 | return nullptr_node; | |
787 | } | |
05765a91 | 788 | if (POINTER_TYPE_P (type) || TYPE_PTRMEM_P (type)) |
c4698a21 | 789 | return fold_if_not_in_template (cp_convert_to_pointer (type, e, complain)); |
684b9d79 | 790 | if (code == VECTOR_TYPE) |
c37ff371 | 791 | { |
792 | tree in_vtype = TREE_TYPE (e); | |
95397ff9 | 793 | if (MAYBE_CLASS_TYPE_P (in_vtype)) |
c37ff371 | 794 | { |
795 | tree ret_val; | |
796 | ret_val = build_type_conversion (type, e); | |
653e5405 | 797 | if (ret_val) |
798 | return ret_val; | |
c4698a21 | 799 | if (complain & tf_error) |
800 | error_at (loc, "%q#T used where a %qT was expected", | |
801 | in_vtype, type); | |
653e5405 | 802 | return error_mark_node; |
c37ff371 | 803 | } |
5d7ed6c7 | 804 | return fold_if_not_in_template (convert_to_vector (type, e)); |
c37ff371 | 805 | } |
c4a8ac95 | 806 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 807 | { |
95397ff9 | 808 | if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e))) |
471086d6 | 809 | { |
810 | tree rval; | |
8999978b | 811 | rval = build_type_conversion (type, e); |
471086d6 | 812 | if (rval) |
813 | return rval; | |
c4698a21 | 814 | else if (complain & tf_error) |
815 | error_at (loc, | |
816 | "%q#T used where a floating point value was expected", | |
817 | TREE_TYPE (e)); | |
471086d6 | 818 | } |
c4a8ac95 | 819 | if (code == REAL_TYPE) |
5d7ed6c7 | 820 | return fold_if_not_in_template (convert_to_real (type, e)); |
c4a8ac95 | 821 | else if (code == COMPLEX_TYPE) |
5d7ed6c7 | 822 | return fold_if_not_in_template (convert_to_complex (type, e)); |
471086d6 | 823 | } |
824 | ||
825 | /* New C++ semantics: since assignment is now based on | |
826 | memberwise copying, if the rhs type is derived from the | |
827 | lhs type, then we may still do a conversion. */ | |
95397ff9 | 828 | if (RECORD_OR_UNION_CODE_P (code)) |
471086d6 | 829 | { |
830 | tree dtype = TREE_TYPE (e); | |
c25194fd | 831 | tree ctor = NULL_TREE; |
471086d6 | 832 | |
471086d6 | 833 | dtype = TYPE_MAIN_VARIANT (dtype); |
834 | ||
471086d6 | 835 | /* Conversion between aggregate types. New C++ semantics allow |
836 | objects of derived type to be cast to objects of base type. | |
837 | Old semantics only allowed this between pointers. | |
838 | ||
839 | There may be some ambiguity between using a constructor | |
840 | vs. using a type conversion operator when both apply. */ | |
841 | ||
0a4be248 | 842 | ctor = e; |
860740a7 | 843 | |
44189c16 | 844 | if (abstract_virtuals_error_sfinae (NULL_TREE, type, complain)) |
8c18e707 | 845 | return error_mark_node; |
6cbb4197 | 846 | |
f82f1250 | 847 | if (BRACE_ENCLOSED_INITIALIZER_P (ctor)) |
c4698a21 | 848 | ctor = perform_implicit_conversion (type, ctor, complain); |
f82f1250 | 849 | else if ((flags & LOOKUP_ONLYCONVERTING) |
850 | && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 851 | /* For copy-initialization, first we create a temp of the proper type |
852 | with a user-defined conversion sequence, then we direct-initialize | |
853 | the target with the temp (see [dcl.init]). */ | |
c4698a21 | 854 | ctor = build_user_type_conversion (type, ctor, flags, complain); |
3eb89cd8 | 855 | else |
f352a3fb | 856 | { |
f1f41a6c | 857 | vec<tree, va_gc> *ctor_vec = make_tree_vector_single (ctor); |
f352a3fb | 858 | ctor = build_special_member_call (NULL_TREE, |
859 | complete_ctor_identifier, | |
860 | &ctor_vec, | |
c4698a21 | 861 | type, flags, complain); |
f352a3fb | 862 | release_tree_vector (ctor_vec); |
863 | } | |
0a4be248 | 864 | if (ctor) |
c4698a21 | 865 | return build_cplus_new (type, ctor, complain); |
471086d6 | 866 | } |
867 | ||
c4698a21 | 868 | if (complain & tf_error) |
a7cc1549 | 869 | { |
870 | /* If the conversion failed and expr was an invalid use of pointer to | |
871 | member function, try to report a meaningful error. */ | |
c4698a21 | 872 | if (invalid_nonstatic_memfn_p (expr, complain)) |
a7cc1549 | 873 | /* We displayed the error message. */; |
874 | else | |
61f69bc9 | 875 | error_at (loc, "conversion from %qT to non-scalar type %qT requested", |
876 | TREE_TYPE (expr), type); | |
a7cc1549 | 877 | } |
471086d6 | 878 | return error_mark_node; |
879 | } | |
880 | ||
b1a8d4ce | 881 | /* When an expression is used in a void context, its value is discarded and |
882 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
883 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
884 | in a void context. The C++ standard does not define what an `access' to an | |
63eff20d | 885 | object is, but there is reason to believe that it is the lvalue to rvalue |
b1a8d4ce | 886 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it |
887 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
888 | indicates that volatile semantics should be the same between C and C++ | |
889 | where ever possible. C leaves it implementation defined as to what | |
890 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
891 | the volatile object `vp' points to, unless that is an incomplete type. For | |
892 | volatile references we do not do this interpretation, because that would | |
893 | make it impossible to ignore the reference return value from functions. We | |
894 | issue warnings in the confusing cases. | |
9031d10b | 895 | |
dab3247a | 896 | The IMPLICIT is ICV_CAST when the user is explicitly converting an expression |
897 | to void via a cast. If an expression is being implicitly converted, IMPLICIT | |
898 | indicates the context of the implicit conversion. */ | |
b1a8d4ce | 899 | |
900 | tree | |
dab3247a | 901 | convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain) |
b1a8d4ce | 902 | { |
61f69bc9 | 903 | location_t loc = EXPR_LOC_OR_HERE (expr); |
904 | ||
9031d10b | 905 | if (expr == error_mark_node |
3d411d73 | 906 | || TREE_TYPE (expr) == error_mark_node) |
907 | return error_mark_node; | |
b2af2a93 | 908 | |
dab3247a | 909 | if (implicit == ICV_CAST) |
f94341bb | 910 | mark_exp_read (expr); |
911 | else | |
912 | { | |
913 | tree exprv = expr; | |
914 | ||
915 | while (TREE_CODE (exprv) == COMPOUND_EXPR) | |
916 | exprv = TREE_OPERAND (exprv, 1); | |
0388391d | 917 | if (DECL_P (exprv) |
918 | || handled_component_p (exprv) | |
86ccc124 | 919 | || INDIRECT_REF_P (exprv)) |
f94341bb | 920 | /* Expr is not being 'used' here, otherwise we whould have |
921 | called mark_{rl}value_use use here, which would have in turn | |
922 | called mark_exp_read. Rather, we call mark_exp_read directly | |
923 | to avoid some warnings when | |
924 | -Wunused-but-set-{variable,parameter} is in effect. */ | |
925 | mark_exp_read (exprv); | |
926 | } | |
b2af2a93 | 927 | |
b1a8d4ce | 928 | if (!TREE_TYPE (expr)) |
929 | return expr; | |
ebd21de4 | 930 | if (invalid_nonstatic_memfn_p (expr, complain)) |
334f6ce1 | 931 | return error_mark_node; |
ed36f1cf | 932 | if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR) |
933 | { | |
ebd21de4 | 934 | if (complain & tf_error) |
61f69bc9 | 935 | error_at (loc, "pseudo-destructor is not called"); |
ed36f1cf | 936 | return error_mark_node; |
937 | } | |
e3cfe3ce | 938 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 939 | return expr; |
940 | switch (TREE_CODE (expr)) | |
941 | { | |
942 | case COND_EXPR: | |
943 | { | |
653e5405 | 944 | /* The two parts of a cond expr might be separate lvalues. */ |
945 | tree op1 = TREE_OPERAND (expr,1); | |
946 | tree op2 = TREE_OPERAND (expr,2); | |
527facbb | 947 | bool side_effects = ((op1 && TREE_SIDE_EFFECTS (op1)) |
948 | || TREE_SIDE_EFFECTS (op2)); | |
dab3247a | 949 | tree new_op1, new_op2; |
527facbb | 950 | new_op1 = NULL_TREE; |
dab3247a | 951 | if (implicit != ICV_CAST && !side_effects) |
952 | { | |
527facbb | 953 | if (op1) |
954 | new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain); | |
dab3247a | 955 | new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain); |
956 | } | |
957 | else | |
958 | { | |
527facbb | 959 | if (op1) |
960 | new_op1 = convert_to_void (op1, ICV_CAST, complain); | |
dab3247a | 961 | new_op2 = convert_to_void (op2, ICV_CAST, complain); |
962 | } | |
9031d10b | 963 | |
527facbb | 964 | expr = build3 (COND_EXPR, TREE_TYPE (new_op2), |
831d52a2 | 965 | TREE_OPERAND (expr, 0), new_op1, new_op2); |
653e5405 | 966 | break; |
b1a8d4ce | 967 | } |
9031d10b | 968 | |
b1a8d4ce | 969 | case COMPOUND_EXPR: |
970 | { | |
653e5405 | 971 | /* The second part of a compound expr contains the value. */ |
972 | tree op1 = TREE_OPERAND (expr,1); | |
dab3247a | 973 | tree new_op1; |
974 | if (implicit != ICV_CAST && !TREE_NO_WARNING (expr)) | |
975 | new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain); | |
976 | else | |
977 | new_op1 = convert_to_void (op1, ICV_CAST, complain); | |
9031d10b | 978 | |
653e5405 | 979 | if (new_op1 != op1) |
e907a2e9 | 980 | { |
831d52a2 | 981 | tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1), |
982 | TREE_OPERAND (expr, 0), new_op1); | |
e907a2e9 | 983 | expr = t; |
984 | } | |
985 | ||
653e5405 | 986 | break; |
b1a8d4ce | 987 | } |
9031d10b | 988 | |
b1a8d4ce | 989 | case NON_LVALUE_EXPR: |
990 | case NOP_EXPR: | |
c0af329c | 991 | /* These have already decayed to rvalue. */ |
b1a8d4ce | 992 | break; |
9031d10b | 993 | |
331bc0ad | 994 | case CALL_EXPR: /* We have a special meaning for volatile void fn(). */ |
b1a8d4ce | 995 | break; |
9031d10b | 996 | |
b1a8d4ce | 997 | case INDIRECT_REF: |
998 | { | |
653e5405 | 999 | tree type = TREE_TYPE (expr); |
1000 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
1001 | == REFERENCE_TYPE; | |
1002 | int is_volatile = TYPE_VOLATILE (type); | |
1003 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
1004 | ||
dc02da7f | 1005 | /* Can't load the value if we don't know the type. */ |
653e5405 | 1006 | if (is_volatile && !is_complete) |
ebd21de4 | 1007 | { |
1008 | if (complain & tf_warning) | |
dab3247a | 1009 | switch (implicit) |
1010 | { | |
1011 | case ICV_CAST: | |
61f69bc9 | 1012 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1013 | "object of incomplete type %qT", type); |
1014 | break; | |
1015 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1016 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1017 | "incomplete type %qT in second operand " |
1018 | "of conditional expression", type); | |
1019 | break; | |
1020 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1021 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1022 | "incomplete type %qT in third operand " |
1023 | "of conditional expression", type); | |
1024 | break; | |
1025 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1026 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1027 | "incomplete type %qT in right operand of " |
1028 | "comma operator", type); | |
1029 | break; | |
1030 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1031 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1032 | "incomplete type %qT in left operand of " |
1033 | "comma operator", type); | |
1034 | break; | |
1035 | case ICV_STATEMENT: | |
61f69bc9 | 1036 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1037 | "incomplete type %qT in statement", type); |
1038 | break; | |
1039 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1040 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1041 | "incomplete type %qT in for increment " |
1042 | "expression", type); | |
1043 | break; | |
1044 | default: | |
1045 | gcc_unreachable (); | |
1046 | } | |
ebd21de4 | 1047 | } |
dc02da7f | 1048 | /* Don't load the value if this is an implicit dereference, or if |
1049 | the type needs to be handled by ctors/dtors. */ | |
dab3247a | 1050 | else if (is_volatile && is_reference) |
ebd21de4 | 1051 | { |
1052 | if (complain & tf_warning) | |
dab3247a | 1053 | switch (implicit) |
1054 | { | |
1055 | case ICV_CAST: | |
61f69bc9 | 1056 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1057 | "object of type %qT", type); |
1058 | break; | |
1059 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1060 | warning_at (loc, 0, "implicit dereference will not access " |
1061 | "object of type %qT in second operand of " | |
dab3247a | 1062 | "conditional expression", type); |
1063 | break; | |
1064 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1065 | warning_at (loc, 0, "implicit dereference will not access " |
1066 | "object of type %qT in third operand of " | |
dab3247a | 1067 | "conditional expression", type); |
1068 | break; | |
1069 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1070 | warning_at (loc, 0, "implicit dereference will not access " |
1071 | "object of type %qT in right operand of " | |
dab3247a | 1072 | "comma operator", type); |
1073 | break; | |
1074 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1075 | warning_at (loc, 0, "implicit dereference will not access " |
1076 | "object of type %qT in left operand of comma " | |
1077 | "operator", type); | |
dab3247a | 1078 | break; |
1079 | case ICV_STATEMENT: | |
61f69bc9 | 1080 | warning_at (loc, 0, "implicit dereference will not access " |
1081 | "object of type %qT in statement", type); | |
dab3247a | 1082 | break; |
1083 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1084 | warning_at (loc, 0, "implicit dereference will not access " |
1085 | "object of type %qT in for increment expression", | |
1086 | type); | |
dab3247a | 1087 | break; |
1088 | default: | |
1089 | gcc_unreachable (); | |
1090 | } | |
ebd21de4 | 1091 | } |
dab3247a | 1092 | else if (is_volatile && TREE_ADDRESSABLE (type)) |
1093 | { | |
1094 | if (complain & tf_warning) | |
1095 | switch (implicit) | |
1096 | { | |
1097 | case ICV_CAST: | |
61f69bc9 | 1098 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1099 | "object of non-trivially-copyable type %qT", |
61f69bc9 | 1100 | type); |
dab3247a | 1101 | break; |
1102 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1103 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1104 | "non-trivially-copyable type %qT in second " |
1105 | "operand of conditional expression", type); | |
1106 | break; | |
1107 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1108 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1109 | "non-trivially-copyable type %qT in third " |
1110 | "operand of conditional expression", type); | |
1111 | break; | |
1112 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1113 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1114 | "non-trivially-copyable type %qT in right " |
1115 | "operand of comma operator", type); | |
1116 | break; | |
1117 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1118 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1119 | "non-trivially-copyable type %qT in left " |
1120 | "operand of comma operator", type); | |
1121 | break; | |
1122 | case ICV_STATEMENT: | |
61f69bc9 | 1123 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1124 | "non-trivially-copyable type %qT in statement", |
61f69bc9 | 1125 | type); |
dab3247a | 1126 | break; |
1127 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1128 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1129 | "non-trivially-copyable type %qT in for " |
1130 | "increment expression", type); | |
1131 | break; | |
1132 | default: | |
1133 | gcc_unreachable (); | |
1134 | } | |
1135 | } | |
dc02da7f | 1136 | if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type)) |
a4d4030b | 1137 | { |
1138 | /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF | |
1139 | operation is stripped off. Note that we don't warn about | |
1140 | - an expression with TREE_NO_WARNING set. (For an example of | |
1141 | such expressions, see build_over_call in call.c.) | |
1142 | - automatic dereferencing of references, since the user cannot | |
3d177e8c | 1143 | control it. (See also warn_if_unused_value() in c-common.c.) */ |
a4d4030b | 1144 | if (warn_unused_value |
dab3247a | 1145 | && implicit != ICV_CAST |
a4d4030b | 1146 | && (complain & tf_warning) |
1147 | && !TREE_NO_WARNING (expr) | |
1148 | && !is_reference) | |
61f69bc9 | 1149 | warning_at (loc, OPT_Wunused_value, "value computed is not used"); |
a4d4030b | 1150 | expr = TREE_OPERAND (expr, 0); |
1151 | } | |
653e5405 | 1152 | |
1153 | break; | |
b1a8d4ce | 1154 | } |
9031d10b | 1155 | |
b1a8d4ce | 1156 | case VAR_DECL: |
1157 | { | |
653e5405 | 1158 | /* External variables might be incomplete. */ |
1159 | tree type = TREE_TYPE (expr); | |
1160 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
1161 | ||
ebd21de4 | 1162 | if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning)) |
dab3247a | 1163 | switch (implicit) |
1164 | { | |
1165 | case ICV_CAST: | |
61f69bc9 | 1166 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1167 | "object %qE of incomplete type %qT", expr, type); |
1168 | break; | |
1169 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1170 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1171 | "not be accessed in second operand of " | |
dab3247a | 1172 | "conditional expression", expr, type); |
1173 | break; | |
1174 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1175 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1176 | "not be accessed in third operand of " | |
dab3247a | 1177 | "conditional expression", expr, type); |
1178 | break; | |
1179 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1180 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1181 | "not be accessed in right operand of comma operator", | |
1182 | expr, type); | |
dab3247a | 1183 | break; |
1184 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1185 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1186 | "not be accessed in left operand of comma operator", | |
1187 | expr, type); | |
dab3247a | 1188 | break; |
1189 | case ICV_STATEMENT: | |
61f69bc9 | 1190 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1191 | "not be accessed in statement", expr, type); | |
dab3247a | 1192 | break; |
1193 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1194 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1195 | "not be accessed in for increment expression", | |
1196 | expr, type); | |
dab3247a | 1197 | break; |
1198 | default: | |
1199 | gcc_unreachable (); | |
1200 | } | |
1201 | ||
653e5405 | 1202 | break; |
b1a8d4ce | 1203 | } |
d9f88785 | 1204 | |
25b3017b | 1205 | case TARGET_EXPR: |
1206 | /* Don't bother with the temporary object returned from a function if | |
1207 | we don't use it and don't need to destroy it. We'll still | |
1208 | allocate space for it in expand_call or declare_return_variable, | |
1209 | but we don't need to track it through all the tree phases. */ | |
67bb1301 | 1210 | if (TARGET_EXPR_IMPLICIT_P (expr) |
25b3017b | 1211 | && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr))) |
1212 | { | |
1213 | tree init = TARGET_EXPR_INITIAL (expr); | |
1214 | if (TREE_CODE (init) == AGGR_INIT_EXPR | |
1215 | && !AGGR_INIT_VIA_CTOR_P (init)) | |
1216 | { | |
c2f47e15 | 1217 | tree fn = AGGR_INIT_EXPR_FN (init); |
389dd41b | 1218 | expr = build_call_array_loc (input_location, |
1219 | TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))), | |
1220 | fn, | |
1221 | aggr_init_expr_nargs (init), | |
1222 | AGGR_INIT_EXPR_ARGP (init)); | |
25b3017b | 1223 | } |
1224 | } | |
1225 | break; | |
1226 | ||
b1a8d4ce | 1227 | default:; |
1228 | } | |
eebd67e7 | 1229 | expr = resolve_nondeduced_context (expr); |
b1a8d4ce | 1230 | { |
1231 | tree probe = expr; | |
9031d10b | 1232 | |
b1a8d4ce | 1233 | if (TREE_CODE (probe) == ADDR_EXPR) |
1234 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 1235 | if (type_unknown_p (probe)) |
1236 | { | |
1237 | /* [over.over] enumerates the places where we can take the address | |
1238 | of an overloaded function, and this is not one of them. */ | |
ebd21de4 | 1239 | if (complain & tf_error) |
dab3247a | 1240 | switch (implicit) |
1241 | { | |
1242 | case ICV_CAST: | |
61f69bc9 | 1243 | error_at (loc, "conversion to void " |
1244 | "cannot resolve address of overloaded function"); | |
dab3247a | 1245 | break; |
1246 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1247 | error_at (loc, "second operand of conditional expression " |
1248 | "cannot resolve address of overloaded function"); | |
dab3247a | 1249 | break; |
1250 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1251 | error_at (loc, "third operand of conditional expression " |
1252 | "cannot resolve address of overloaded function"); | |
dab3247a | 1253 | break; |
1254 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1255 | error_at (loc, "right operand of comma operator " |
1256 | "cannot resolve address of overloaded function"); | |
dab3247a | 1257 | break; |
1258 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1259 | error_at (loc, "left operand of comma operator " |
1260 | "cannot resolve address of overloaded function"); | |
dab3247a | 1261 | break; |
1262 | case ICV_STATEMENT: | |
61f69bc9 | 1263 | error_at (loc, "statement " |
1264 | "cannot resolve address of overloaded function"); | |
dab3247a | 1265 | break; |
1266 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1267 | error_at (loc, "for increment expression " |
1268 | "cannot resolve address of overloaded function"); | |
dab3247a | 1269 | break; |
1270 | } | |
ebd21de4 | 1271 | else |
1272 | return error_mark_node; | |
ea720917 | 1273 | expr = void_zero_node; |
2e0e6579 | 1274 | } |
dab3247a | 1275 | else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe)) |
2056769e | 1276 | { |
1277 | /* Only warn when there is no &. */ | |
ebd21de4 | 1278 | if (complain & tf_warning) |
dab3247a | 1279 | switch (implicit) |
1280 | { | |
1281 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1282 | warning_at (loc, OPT_Waddress, |
1283 | "second operand of conditional expression " | |
1284 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1285 | break; |
1286 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1287 | warning_at (loc, OPT_Waddress, |
1288 | "third operand of conditional expression " | |
1289 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1290 | break; |
1291 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1292 | warning_at (loc, OPT_Waddress, |
1293 | "right operand of comma operator " | |
1294 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1295 | break; |
1296 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1297 | warning_at (loc, OPT_Waddress, |
1298 | "left operand of comma operator " | |
1299 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1300 | break; |
1301 | case ICV_STATEMENT: | |
61f69bc9 | 1302 | warning_at (loc, OPT_Waddress, |
1303 | "statement is a reference, not call, to function %qE", | |
1304 | expr); | |
dab3247a | 1305 | break; |
1306 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1307 | warning_at (loc, OPT_Waddress, |
1308 | "for increment expression " | |
1309 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1310 | break; |
1311 | default: | |
1312 | gcc_unreachable (); | |
1313 | } | |
1314 | ||
2056769e | 1315 | if (TREE_CODE (expr) == COMPONENT_REF) |
1316 | expr = TREE_OPERAND (expr, 0); | |
1317 | } | |
b1a8d4ce | 1318 | } |
9031d10b | 1319 | |
e3cfe3ce | 1320 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 1321 | { |
dab3247a | 1322 | if (implicit != ICV_CAST |
5e2a4133 | 1323 | && warn_unused_value |
1324 | && !TREE_NO_WARNING (expr) | |
1325 | && !processing_template_decl) | |
1fe46df1 | 1326 | { |
1327 | /* The middle end does not warn about expressions that have | |
1328 | been explicitly cast to void, so we must do so here. */ | |
ebd21de4 | 1329 | if (!TREE_SIDE_EFFECTS (expr)) { |
1330 | if (complain & tf_warning) | |
dab3247a | 1331 | switch (implicit) |
1332 | { | |
1333 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1334 | warning_at (loc, OPT_Wunused_value, |
1335 | "second operand of conditional expression " | |
1336 | "has no effect"); | |
dab3247a | 1337 | break; |
1338 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1339 | warning_at (loc, OPT_Wunused_value, |
1340 | "third operand of conditional expression " | |
1341 | "has no effect"); | |
dab3247a | 1342 | break; |
1343 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1344 | warning_at (loc, OPT_Wunused_value, |
1345 | "right operand of comma operator has no effect"); | |
dab3247a | 1346 | break; |
1347 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1348 | warning_at (loc, OPT_Wunused_value, |
1349 | "left operand of comma operator has no effect"); | |
dab3247a | 1350 | break; |
1351 | case ICV_STATEMENT: | |
61f69bc9 | 1352 | warning_at (loc, OPT_Wunused_value, |
1353 | "statement has no effect"); | |
dab3247a | 1354 | break; |
1355 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1356 | warning_at (loc, OPT_Wunused_value, |
1357 | "for increment expression has no effect"); | |
dab3247a | 1358 | break; |
1359 | default: | |
1360 | gcc_unreachable (); | |
1361 | } | |
ebd21de4 | 1362 | } |
9031d10b | 1363 | else |
1364 | { | |
1fe46df1 | 1365 | tree e; |
1366 | enum tree_code code; | |
607a5d68 | 1367 | enum tree_code_class tclass; |
9031d10b | 1368 | |
1fe46df1 | 1369 | e = expr; |
1370 | /* We might like to warn about (say) "(int) f()", as the | |
1371 | cast has no effect, but the compiler itself will | |
1372 | generate implicit conversions under some | |
324d8f2d | 1373 | circumstances. (For example a block copy will be |
1fe46df1 | 1374 | turned into a call to "__builtin_memcpy", with a |
1375 | conversion of the return value to an appropriate | |
1376 | type.) So, to avoid false positives, we strip | |
416ce344 | 1377 | conversions. Do not use STRIP_NOPs because it will |
1378 | not strip conversions to "void", as that is not a | |
1379 | mode-preserving conversion. */ | |
1380 | while (TREE_CODE (e) == NOP_EXPR) | |
1381 | e = TREE_OPERAND (e, 0); | |
1fe46df1 | 1382 | |
1383 | code = TREE_CODE (e); | |
607a5d68 | 1384 | tclass = TREE_CODE_CLASS (code); |
1385 | if ((tclass == tcc_comparison | |
1386 | || tclass == tcc_unary | |
1387 | || (tclass == tcc_binary | |
1fe46df1 | 1388 | && !(code == MODIFY_EXPR |
1389 | || code == INIT_EXPR | |
1390 | || code == PREDECREMENT_EXPR | |
1391 | || code == PREINCREMENT_EXPR | |
1392 | || code == POSTDECREMENT_EXPR | |
1393 | || code == POSTINCREMENT_EXPR))) | |
ebd21de4 | 1394 | && (complain & tf_warning)) |
61f69bc9 | 1395 | warning_at (loc, OPT_Wunused_value, "value computed is not used"); |
1fe46df1 | 1396 | } |
1397 | } | |
00fa9079 | 1398 | expr = build1 (CONVERT_EXPR, void_type_node, expr); |
b1a8d4ce | 1399 | } |
de5ad4cb | 1400 | if (! TREE_SIDE_EFFECTS (expr)) |
1401 | expr = void_zero_node; | |
b1a8d4ce | 1402 | return expr; |
1403 | } | |
1404 | ||
d81e00a4 | 1405 | /* Create an expression whose value is that of EXPR, |
1406 | converted to type TYPE. The TREE_TYPE of the value | |
1407 | is always TYPE. This function implements all reasonable | |
1408 | conversions; callers should filter out those that are | |
c4a8ac95 | 1409 | not permitted by the language being compiled. |
1410 | ||
1411 | Most of this routine is from build_reinterpret_cast. | |
1412 | ||
a17c2a3a | 1413 | The back end cannot call cp_convert (what was convert) because |
c4a8ac95 | 1414 | conversions to/from basetypes may involve memory references |
1415 | (vbases) and adding or subtracting small values (multiple | |
1416 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 1417 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 1418 | |
1419 | Also, if we ever support range variables, we'll probably also have to | |
1420 | do a little bit more work. */ | |
d81e00a4 | 1421 | |
1422 | tree | |
35771a9a | 1423 | convert (tree type, tree expr) |
d81e00a4 | 1424 | { |
c4a8ac95 | 1425 | tree intype; |
1426 | ||
1427 | if (type == error_mark_node || expr == error_mark_node) | |
1428 | return error_mark_node; | |
1429 | ||
c4a8ac95 | 1430 | intype = TREE_TYPE (expr); |
1431 | ||
6686e84d | 1432 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
13f0eb20 | 1433 | return fold_if_not_in_template (build_nop (type, expr)); |
c4a8ac95 | 1434 | |
1435 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
c4698a21 | 1436 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION, |
1437 | tf_warning_or_error); | |
d81e00a4 | 1438 | } |
1439 | ||
c4a8ac95 | 1440 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 1441 | are not normally allowed due to access restrictions |
1442 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 1443 | |
471086d6 | 1444 | tree |
c4698a21 | 1445 | convert_force (tree type, tree expr, int convtype, tsubst_flags_t complain) |
471086d6 | 1446 | { |
cd16867a | 1447 | tree e = expr; |
1448 | enum tree_code code = TREE_CODE (type); | |
471086d6 | 1449 | |
1450 | if (code == REFERENCE_TYPE) | |
9031d10b | 1451 | return (fold_if_not_in_template |
c4698a21 | 1452 | (convert_to_reference (type, e, CONV_C_CAST, 0, |
1453 | NULL_TREE, complain))); | |
471086d6 | 1454 | |
1455 | if (code == POINTER_TYPE) | |
c4698a21 | 1456 | return fold_if_not_in_template (convert_to_pointer_force (type, e, |
1457 | complain)); | |
471086d6 | 1458 | |
ac9386a0 | 1459 | /* From typeck.c convert_for_assignment */ |
471086d6 | 1460 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
1461 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
1462 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 1463 | || integer_zerop (e) |
1464 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1465 | && TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 1466 | /* compatible pointer to member functions. */ |
1467 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1, | |
c4698a21 | 1468 | /*c_cast_p=*/1, complain); |
a74e8896 | 1469 | |
c4698a21 | 1470 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL, complain); |
471086d6 | 1471 | } |
1472 | ||
471086d6 | 1473 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1474 | exists, return the attempted conversion. This may | |
1475 | return ERROR_MARK_NODE if the conversion is not | |
1476 | allowed (references private members, etc). | |
1477 | If no conversion exists, NULL_TREE is returned. | |
1478 | ||
ce28ee2e | 1479 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit |
1480 | object parameter, or by the second standard conversion sequence if | |
1481 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1482 | (jason 8/9/95) */ | |
471086d6 | 1483 | |
ef9571e5 | 1484 | static tree |
8999978b | 1485 | build_type_conversion (tree xtype, tree expr) |
471086d6 | 1486 | { |
1487 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1488 | into the required type. */ |
66bbeb85 | 1489 | return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL, |
1490 | tf_warning_or_error); | |
471086d6 | 1491 | } |
1492 | ||
1e66592c | 1493 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1494 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
35771a9a | 1495 | which indicates which types are suitable. If COMPLAIN is true, complain |
1e66592c | 1496 | about ambiguity; otherwise, the caller will deal with it. */ |
471086d6 | 1497 | |
1e66592c | 1498 | tree |
35771a9a | 1499 | build_expr_type_conversion (int desires, tree expr, bool complain) |
471086d6 | 1500 | { |
1e66592c | 1501 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1502 | tree conv = NULL_TREE; |
bdd152ce | 1503 | tree winner = NULL_TREE; |
471086d6 | 1504 | |
9031d10b | 1505 | if (expr == null_node |
1506 | && (desires & WANT_INT) | |
954885ed | 1507 | && !(desires & WANT_NULL)) |
db30b351 | 1508 | { |
1509 | source_location loc = | |
1510 | expansion_point_location_if_in_system_header (input_location); | |
1511 | ||
1512 | warning_at (loc, OPT_Wconversion_null, | |
1513 | "converting NULL to non-pointer type"); | |
1514 | } | |
9031d10b | 1515 | |
3d411d73 | 1516 | if (basetype == error_mark_node) |
1517 | return error_mark_node; | |
1518 | ||
95397ff9 | 1519 | if (! MAYBE_CLASS_TYPE_P (basetype)) |
bdd152ce | 1520 | switch (TREE_CODE (basetype)) |
1521 | { | |
1522 | case INTEGER_TYPE: | |
954885ed | 1523 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1524 | return expr; |
1525 | /* else fall through... */ | |
1526 | ||
1527 | case BOOLEAN_TYPE: | |
1528 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1529 | case ENUMERAL_TYPE: | |
1530 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1531 | case REAL_TYPE: | |
1532 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1533 | case POINTER_TYPE: | |
1534 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
9031d10b | 1535 | |
bdd152ce | 1536 | case FUNCTION_TYPE: |
1537 | case ARRAY_TYPE: | |
4405c1ad | 1538 | return (desires & WANT_POINTER) ? decay_conversion (expr, |
1539 | tf_warning_or_error) | |
653e5405 | 1540 | : NULL_TREE; |
96ec9e30 | 1541 | |
64ec1ad6 | 1542 | case COMPLEX_TYPE: |
96ec9e30 | 1543 | case VECTOR_TYPE: |
64ec1ad6 | 1544 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1545 | return NULL_TREE; |
1546 | switch (TREE_CODE (TREE_TYPE (basetype))) | |
1547 | { | |
1548 | case INTEGER_TYPE: | |
1549 | case BOOLEAN_TYPE: | |
1550 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1551 | case ENUMERAL_TYPE: | |
1552 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1553 | case REAL_TYPE: | |
1554 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1555 | default: | |
1556 | return NULL_TREE; | |
1557 | } | |
1558 | ||
bdd152ce | 1559 | default: |
1560 | return NULL_TREE; | |
1561 | } | |
1562 | ||
1563 | /* The code for conversions from class type is currently only used for | |
1564 | delete expressions. Other expressions are handled by build_new_op. */ | |
a5f2d620 | 1565 | if (!complete_type_or_maybe_complain (basetype, expr, complain)) |
f8182e08 | 1566 | return error_mark_node; |
1567 | if (!TYPE_HAS_CONVERSION (basetype)) | |
bdd152ce | 1568 | return NULL_TREE; |
1569 | ||
9960d752 | 1570 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) |
bdd152ce | 1571 | { |
1572 | int win = 0; | |
1573 | tree candidate; | |
1574 | tree cand = TREE_VALUE (conv); | |
c1ca2f12 | 1575 | cand = OVL_CURRENT (cand); |
bdd152ce | 1576 | |
1577 | if (winner && winner == cand) | |
1578 | continue; | |
1579 | ||
cf7aa2e5 | 1580 | if (DECL_NONCONVERTING_P (cand)) |
1581 | continue; | |
1582 | ||
da7eaa22 | 1583 | if (TREE_CODE (cand) == TEMPLATE_DECL) |
1584 | { | |
1585 | if (complain) | |
1586 | { | |
1587 | error ("ambiguous default type conversion from %qT", | |
1588 | basetype); | |
1589 | error (" candidate conversions include %qD", cand); | |
1590 | } | |
1591 | return error_mark_node; | |
1592 | } | |
1593 | ||
ef4534a3 | 1594 | candidate = non_reference (TREE_TYPE (TREE_TYPE (cand))); |
bdd152ce | 1595 | |
1596 | switch (TREE_CODE (candidate)) | |
1597 | { | |
1598 | case BOOLEAN_TYPE: | |
1599 | case INTEGER_TYPE: | |
1600 | win = (desires & WANT_INT); break; | |
1601 | case ENUMERAL_TYPE: | |
1602 | win = (desires & WANT_ENUM); break; | |
1603 | case REAL_TYPE: | |
1604 | win = (desires & WANT_FLOAT); break; | |
1605 | case POINTER_TYPE: | |
1606 | win = (desires & WANT_POINTER); break; | |
1607 | ||
64ec1ad6 | 1608 | case COMPLEX_TYPE: |
96ec9e30 | 1609 | case VECTOR_TYPE: |
64ec1ad6 | 1610 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1611 | break; |
1612 | switch (TREE_CODE (TREE_TYPE (candidate))) | |
1613 | { | |
1614 | case BOOLEAN_TYPE: | |
1615 | case INTEGER_TYPE: | |
1616 | win = (desires & WANT_INT); break; | |
1617 | case ENUMERAL_TYPE: | |
1618 | win = (desires & WANT_ENUM); break; | |
1619 | case REAL_TYPE: | |
1620 | win = (desires & WANT_FLOAT); break; | |
1621 | default: | |
1622 | break; | |
1623 | } | |
1624 | break; | |
1625 | ||
bdd152ce | 1626 | default: |
1627 | break; | |
1628 | } | |
1629 | ||
1630 | if (win) | |
1631 | { | |
1632 | if (winner) | |
1633 | { | |
1634 | if (complain) | |
1635 | { | |
0a25aad6 | 1636 | error ("ambiguous default type conversion from %qT", |
653e5405 | 1637 | basetype); |
0a25aad6 | 1638 | error (" candidate conversions include %qD and %qD", |
653e5405 | 1639 | winner, cand); |
bdd152ce | 1640 | } |
1641 | return error_mark_node; | |
1642 | } | |
1643 | else | |
1644 | winner = cand; | |
1645 | } | |
1646 | } | |
1e66592c | 1647 | |
bdd152ce | 1648 | if (winner) |
1649 | { | |
ef4534a3 | 1650 | tree type = non_reference (TREE_TYPE (TREE_TYPE (winner))); |
66bbeb85 | 1651 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL, |
1652 | tf_warning_or_error); | |
471086d6 | 1653 | } |
1e66592c | 1654 | |
985e9ee0 | 1655 | return NULL_TREE; |
471086d6 | 1656 | } |
bc3887cf | 1657 | |
96624a9e | 1658 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1659 | ||
bc3887cf | 1660 | tree |
35771a9a | 1661 | type_promotes_to (tree type) |
bc3887cf | 1662 | { |
2b3c93a3 | 1663 | tree promoted_type; |
1664 | ||
ce28ee2e | 1665 | if (type == error_mark_node) |
1666 | return error_mark_node; | |
1667 | ||
bc3887cf | 1668 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1669 | |
2b3c93a3 | 1670 | /* Check for promotions of target-defined types first. */ |
1671 | promoted_type = targetm.promoted_type (type); | |
1672 | if (promoted_type) | |
1673 | return promoted_type; | |
1674 | ||
bb0726a1 | 1675 | /* bool always promotes to int (not unsigned), even if it's the same |
1676 | size. */ | |
9e1a8234 | 1677 | if (TREE_CODE (type) == BOOLEAN_TYPE) |
bb0726a1 | 1678 | type = integer_type_node; |
1679 | ||
9fd75d52 | 1680 | /* Scoped enums don't promote, but pretend they do for backward ABI bug |
1681 | compatibility wrt varargs. */ | |
72fc0f64 | 1682 | else if (SCOPED_ENUM_P (type) && abi_version_at_least (6)) |
1683 | ; | |
1684 | ||
bb0726a1 | 1685 | /* Normally convert enums to int, but convert wide enums to something |
1686 | wider. */ | |
1687 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
924bbf02 | 1688 | || type == char16_type_node |
1689 | || type == char32_type_node | |
bb0726a1 | 1690 | || type == wchar_type_node) |
6c9497b1 | 1691 | { |
1692 | int precision = MAX (TYPE_PRECISION (type), | |
1693 | TYPE_PRECISION (integer_type_node)); | |
771d21fa | 1694 | tree totype = c_common_type_for_size (precision, 0); |
72fc0f64 | 1695 | if (SCOPED_ENUM_P (type)) |
1696 | warning (OPT_Wabi, "scoped enum %qT will not promote to an integral " | |
1697 | "type in a future version of GCC", type); | |
bb9c1a09 | 1698 | if (TREE_CODE (type) == ENUMERAL_TYPE) |
1699 | type = ENUM_UNDERLYING_TYPE (type); | |
78a8ed03 | 1700 | if (TYPE_UNSIGNED (type) |
6c9497b1 | 1701 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) |
771d21fa | 1702 | type = c_common_type_for_size (precision, 1); |
6c9497b1 | 1703 | else |
1704 | type = totype; | |
1705 | } | |
d7aeef06 | 1706 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1707 | { |
d0acef9e | 1708 | /* Retain unsignedness if really not getting bigger. */ |
78a8ed03 | 1709 | if (TYPE_UNSIGNED (type) |
d0acef9e | 1710 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1711 | type = unsigned_type_node; |
1712 | else | |
1713 | type = integer_type_node; | |
1714 | } | |
1715 | else if (type == float_type_node) | |
1716 | type = double_type_node; | |
9031d10b | 1717 | |
a681799d | 1718 | return type; |
bc3887cf | 1719 | } |
668ae905 | 1720 | |
668ae905 | 1721 | /* The routines below this point are carefully written to conform to |
1722 | the standard. They use the same terminology, and follow the rules | |
1723 | closely. Although they are used only in pt.c at the moment, they | |
1724 | should presumably be used everywhere in the future. */ | |
1725 | ||
1146f179 | 1726 | /* Attempt to perform qualification conversions on EXPR to convert it |
1727 | to TYPE. Return the resulting expression, or error_mark_node if | |
1728 | the conversion was impossible. */ | |
1729 | ||
9031d10b | 1730 | tree |
35771a9a | 1731 | perform_qualification_conversions (tree type, tree expr) |
668ae905 | 1732 | { |
1bc16cab | 1733 | tree expr_type; |
1734 | ||
1735 | expr_type = TREE_TYPE (expr); | |
1736 | ||
3b087710 | 1737 | if (same_type_p (type, expr_type)) |
1738 | return expr; | |
1739 | else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type) | |
1740 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type))) | |
1bc16cab | 1741 | return build_nop (type, expr); |
05765a91 | 1742 | else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (expr_type) |
1bc16cab | 1743 | && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type), |
1744 | TYPE_PTRMEM_CLASS_TYPE (expr_type)) | |
1745 | && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type), | |
1746 | TYPE_PTRMEM_POINTED_TO_TYPE (expr_type))) | |
1747 | return build_nop (type, expr); | |
1146f179 | 1748 | else |
1749 | return error_mark_node; | |
668ae905 | 1750 | } |