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471086d6 | 1 | /* Language-level data type conversion for GNU C++. |
107c7f39 | 2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, |
1e74225a | 3 | 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, |
4405c1ad | 4 | 2011, 2012 Free Software Foundation, Inc. |
471086d6 | 5 | Hacked by Michael Tiemann (tiemann@cygnus.com) |
6 | ||
6f0d25a6 | 7 | This file is part of GCC. |
471086d6 | 8 | |
6f0d25a6 | 9 | GCC is free software; you can redistribute it and/or modify |
471086d6 | 10 | it under the terms of the GNU General Public License as published by |
aa139c3f | 11 | the Free Software Foundation; either version 3, or (at your option) |
471086d6 | 12 | any later version. |
13 | ||
6f0d25a6 | 14 | GCC is distributed in the hope that it will be useful, |
471086d6 | 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
aa139c3f | 20 | along with GCC; see the file COPYING3. If not see |
21 | <http://www.gnu.org/licenses/>. */ | |
471086d6 | 22 | |
23 | ||
af86cc06 | 24 | /* This file contains the functions for converting C++ expressions |
471086d6 | 25 | to different data types. The only entry point is `convert'. |
26 | Every language front end must have a `convert' function | |
27 | but what kind of conversions it does will depend on the language. */ | |
28 | ||
29 | #include "config.h" | |
b3ef7553 | 30 | #include "system.h" |
805e22b2 | 31 | #include "coretypes.h" |
32 | #include "tm.h" | |
471086d6 | 33 | #include "tree.h" |
34 | #include "flags.h" | |
35 | #include "cp-tree.h" | |
ca82e026 | 36 | #include "intl.h" |
471086d6 | 37 | #include "convert.h" |
2e8226f7 | 38 | #include "decl.h" |
7a979707 | 39 | #include "target.h" |
96624a9e | 40 | |
c4698a21 | 41 | static tree cp_convert_to_pointer (tree, tree, tsubst_flags_t); |
42 | static tree convert_to_pointer_force (tree, tree, tsubst_flags_t); | |
ef9571e5 | 43 | static tree build_type_conversion (tree, tree); |
c4698a21 | 44 | static tree build_up_reference (tree, tree, int, tree, tsubst_flags_t); |
61f69bc9 | 45 | static void warn_ref_binding (location_t, tree, tree, tree); |
71ccdfff | 46 | |
471086d6 | 47 | /* Change of width--truncation and extension of integers or reals-- |
48 | is represented with NOP_EXPR. Proper functioning of many things | |
49 | assumes that no other conversions can be NOP_EXPRs. | |
50 | ||
51 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
52 | Converting integer to real uses FLOAT_EXPR | |
53 | and real to integer uses FIX_TRUNC_EXPR. | |
54 | ||
55 | Here is a list of all the functions that assume that widening and | |
56 | narrowing is always done with a NOP_EXPR: | |
57 | In convert.c, convert_to_integer. | |
58 | In c-typeck.c, build_binary_op_nodefault (boolean ops), | |
653e5405 | 59 | and c_common_truthvalue_conversion. |
471086d6 | 60 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
61 | In fold-const.c: fold. | |
62 | In tree.c: get_narrower and get_unwidened. | |
63 | ||
64 | C++: in multiple-inheritance, converting between pointers may involve | |
65 | adjusting them by a delta stored within the class definition. */ | |
66 | \f | |
67 | /* Subroutines of `convert'. */ | |
68 | ||
471086d6 | 69 | /* if converting pointer to pointer |
70 | if dealing with classes, check for derived->base or vice versa | |
71 | else if dealing with method pointers, delegate | |
72 | else convert blindly | |
73 | else if converting class, pass off to build_type_conversion | |
e5ead12a | 74 | else try C-style pointer conversion. */ |
96624a9e | 75 | |
471086d6 | 76 | static tree |
c4698a21 | 77 | cp_convert_to_pointer (tree type, tree expr, tsubst_flags_t complain) |
471086d6 | 78 | { |
cd16867a | 79 | tree intype = TREE_TYPE (expr); |
80 | enum tree_code form; | |
f82eeb87 | 81 | tree rval; |
61f69bc9 | 82 | location_t loc = EXPR_LOC_OR_HERE (expr); |
83 | ||
8bf328bf | 84 | if (intype == error_mark_node) |
85 | return error_mark_node; | |
74002e1d | 86 | |
95397ff9 | 87 | if (MAYBE_CLASS_TYPE_P (intype)) |
96624a9e | 88 | { |
96624a9e | 89 | intype = complete_type (intype); |
4b72716d | 90 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 91 | { |
c4698a21 | 92 | if (complain & tf_error) |
93 | error_at (loc, "can%'t convert from incomplete type %qT to %qT", | |
94 | intype, type); | |
96624a9e | 95 | return error_mark_node; |
96 | } | |
97 | ||
8999978b | 98 | rval = build_type_conversion (type, expr); |
96624a9e | 99 | if (rval) |
100 | { | |
c4698a21 | 101 | if ((complain & tf_error) |
102 | && rval == error_mark_node) | |
61f69bc9 | 103 | error_at (loc, "conversion of %qE from %qT to %qT is ambiguous", |
104 | expr, intype, type); | |
96624a9e | 105 | return rval; |
106 | } | |
107 | } | |
108 | ||
860740a7 | 109 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 110 | if (TREE_CODE (type) == POINTER_TYPE |
111 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
e3cfe3ce | 112 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 113 | { |
6ab399e8 | 114 | if (TYPE_PTRMEMFUNC_P (intype) |
115 | || TREE_CODE (intype) == METHOD_TYPE) | |
c4698a21 | 116 | return convert_member_func_to_ptr (type, expr, complain); |
a63bc44c | 117 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) |
118 | return build_nop (type, expr); | |
38281c46 | 119 | intype = TREE_TYPE (expr); |
120 | } | |
121 | ||
311e42bc | 122 | if (expr == error_mark_node) |
123 | return error_mark_node; | |
124 | ||
74002e1d | 125 | form = TREE_CODE (intype); |
126 | ||
2b77484d | 127 | if (POINTER_TYPE_P (intype)) |
471086d6 | 128 | { |
129 | intype = TYPE_MAIN_VARIANT (intype); | |
130 | ||
131 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 132 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 133 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
95397ff9 | 134 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
135 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
4a2680fc | 136 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
471086d6 | 137 | { |
138 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 139 | tree binfo; |
8999978b | 140 | tree intype_class; |
141 | tree type_class; | |
142 | bool same_p; | |
4a2680fc | 143 | |
8999978b | 144 | intype_class = TREE_TYPE (intype); |
145 | type_class = TREE_TYPE (type); | |
146 | ||
9031d10b | 147 | same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class), |
8999978b | 148 | TYPE_MAIN_VARIANT (type_class)); |
149 | binfo = NULL_TREE; | |
c0af329c | 150 | /* Try derived to base conversion. */ |
8999978b | 151 | if (!same_p) |
ae260dcc | 152 | binfo = lookup_base (intype_class, type_class, ba_check, |
153 | NULL, complain); | |
8999978b | 154 | if (!same_p && !binfo) |
471086d6 | 155 | { |
c0af329c | 156 | /* Try base to derived conversion. */ |
ae260dcc | 157 | binfo = lookup_base (type_class, intype_class, ba_check, |
158 | NULL, complain); | |
471086d6 | 159 | code = MINUS_EXPR; |
160 | } | |
4a2680fc | 161 | if (binfo == error_mark_node) |
162 | return error_mark_node; | |
8999978b | 163 | if (binfo || same_p) |
471086d6 | 164 | { |
8999978b | 165 | if (binfo) |
c4698a21 | 166 | expr = build_base_path (code, expr, binfo, 0, complain); |
c0af329c | 167 | /* Add any qualifier conversions. */ |
8999978b | 168 | return build_nop (type, expr); |
471086d6 | 169 | } |
170 | } | |
471086d6 | 171 | |
1bc16cab | 172 | if (TYPE_PTRMEMFUNC_P (type)) |
bea7d742 | 173 | { |
c4698a21 | 174 | if (complain & tf_error) |
175 | error_at (loc, "cannot convert %qE from type %qT to type %qT", | |
176 | expr, intype, type); | |
1bc16cab | 177 | return error_mark_node; |
178 | } | |
a17aefa2 | 179 | |
1bc16cab | 180 | return build_nop (type, expr); |
181 | } | |
05765a91 | 182 | else if ((TYPE_PTRDATAMEM_P (type) && TYPE_PTRDATAMEM_P (intype)) |
e5ead12a | 183 | || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) |
184 | return convert_ptrmem (type, expr, /*allow_inverse_p=*/false, | |
c4698a21 | 185 | /*c_cast_p=*/false, complain); |
2b77484d | 186 | else if (TYPE_PTRMEMFUNC_P (intype)) |
187 | { | |
a63bc44c | 188 | if (!warn_pmf2ptr) |
189 | { | |
190 | if (TREE_CODE (expr) == PTRMEM_CST) | |
c4698a21 | 191 | return cp_convert_to_pointer (type, PTRMEM_CST_MEMBER (expr), |
192 | complain); | |
a63bc44c | 193 | else if (TREE_CODE (expr) == OFFSET_REF) |
194 | { | |
195 | tree object = TREE_OPERAND (expr, 0); | |
196 | return get_member_function_from_ptrfunc (&object, | |
4405c1ad | 197 | TREE_OPERAND (expr, 1), |
c4698a21 | 198 | complain); |
a63bc44c | 199 | } |
200 | } | |
61f69bc9 | 201 | error_at (loc, "cannot convert %qE from type %qT to type %qT", |
202 | expr, intype, type); | |
2b77484d | 203 | return error_mark_node; |
204 | } | |
471086d6 | 205 | |
ef434176 | 206 | if (null_ptr_cst_p (expr)) |
471086d6 | 207 | { |
c4698a21 | 208 | if ((complain & tf_warning) |
209 | && c_inhibit_evaluation_warnings == 0 | |
8fe701f5 | 210 | && !NULLPTR_TYPE_P (TREE_TYPE (expr))) |
61f69bc9 | 211 | warning_at (loc, OPT_Wzero_as_null_pointer_constant, |
212 | "zero as null pointer constant"); | |
8fe701f5 | 213 | |
2b77484d | 214 | if (TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 215 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
c4698a21 | 216 | /*c_cast_p=*/false, complain); |
ad63a0fc | 217 | |
05765a91 | 218 | if (TYPE_PTRDATAMEM_P (type)) |
7c446c95 | 219 | { |
220 | /* A NULL pointer-to-member is represented by -1, not by | |
221 | zero. */ | |
697bbc3f | 222 | expr = build_int_cst_type (type, -1); |
7c446c95 | 223 | } |
ad63a0fc | 224 | else |
7016c612 | 225 | expr = build_int_cst (type, 0); |
9031d10b | 226 | |
471086d6 | 227 | return expr; |
228 | } | |
05765a91 | 229 | else if (TYPE_PTRMEM_P (type) && INTEGRAL_CODE_P (form)) |
de1f960a | 230 | { |
c4698a21 | 231 | if (complain & tf_error) |
232 | error_at (loc, "invalid conversion from %qT to %qT", intype, type); | |
de1f960a | 233 | return error_mark_node; |
234 | } | |
471086d6 | 235 | |
bb0726a1 | 236 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 237 | { |
c5aa1e92 | 238 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 239 | return build1 (CONVERT_EXPR, type, expr); |
c4698a21 | 240 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr, |
241 | complain); | |
092b1d6f | 242 | /* Modes may be different but sizes should be the same. There |
243 | is supposed to be some integral type that is the same width | |
244 | as a pointer. */ | |
245 | gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
246 | == GET_MODE_SIZE (TYPE_MODE (type))); | |
9031d10b | 247 | |
471086d6 | 248 | return convert_to_pointer (type, expr); |
249 | } | |
250 | ||
cc4d0855 | 251 | if (type_unknown_p (expr)) |
c4698a21 | 252 | return instantiate_type (type, expr, complain); |
cc4d0855 | 253 | |
c4698a21 | 254 | if (complain & tf_error) |
255 | error_at (loc, "cannot convert %qE from type %qT to type %qT", | |
256 | expr, intype, type); | |
471086d6 | 257 | return error_mark_node; |
258 | } | |
259 | ||
260 | /* Like convert, except permit conversions to take place which | |
261 | are not normally allowed due to access restrictions | |
262 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 263 | |
471086d6 | 264 | static tree |
c4698a21 | 265 | convert_to_pointer_force (tree type, tree expr, tsubst_flags_t complain) |
471086d6 | 266 | { |
cd16867a | 267 | tree intype = TREE_TYPE (expr); |
268 | enum tree_code form = TREE_CODE (intype); | |
9031d10b | 269 | |
471086d6 | 270 | if (form == POINTER_TYPE) |
271 | { | |
272 | intype = TYPE_MAIN_VARIANT (intype); | |
273 | ||
274 | if (TYPE_MAIN_VARIANT (type) != intype | |
275 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
95397ff9 | 276 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
277 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
471086d6 | 278 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
279 | { | |
280 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 281 | tree binfo; |
282 | ||
283 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
ae260dcc | 284 | ba_unique, NULL, complain); |
4a2680fc | 285 | if (!binfo) |
471086d6 | 286 | { |
4a2680fc | 287 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
ae260dcc | 288 | ba_unique, NULL, complain); |
4a2680fc | 289 | code = MINUS_EXPR; |
471086d6 | 290 | } |
4a2680fc | 291 | if (binfo == error_mark_node) |
292 | return error_mark_node; | |
293 | if (binfo) | |
471086d6 | 294 | { |
c4698a21 | 295 | expr = build_base_path (code, expr, binfo, 0, complain); |
653e5405 | 296 | if (expr == error_mark_node) |
297 | return error_mark_node; | |
c0af329c | 298 | /* Add any qualifier conversions. */ |
4a2680fc | 299 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
300 | TREE_TYPE (type))) | |
8999978b | 301 | expr = build_nop (type, expr); |
4a2680fc | 302 | return expr; |
471086d6 | 303 | } |
471086d6 | 304 | } |
471086d6 | 305 | } |
306 | ||
c4698a21 | 307 | return cp_convert_to_pointer (type, expr, complain); |
471086d6 | 308 | } |
309 | ||
310 | /* We are passing something to a function which requires a reference. | |
311 | The type we are interested in is in TYPE. The initial | |
312 | value we have to begin with is in ARG. | |
313 | ||
314 | FLAGS controls how we manage access checking. | |
ca106ab1 | 315 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
316 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 317 | |
471086d6 | 318 | static tree |
c4698a21 | 319 | build_up_reference (tree type, tree arg, int flags, tree decl, |
320 | tsubst_flags_t complain) | |
471086d6 | 321 | { |
c76251c1 | 322 | tree rval; |
0543e7a9 | 323 | tree argtype = TREE_TYPE (arg); |
471086d6 | 324 | tree target_type = TREE_TYPE (type); |
471086d6 | 325 | |
b4df430b | 326 | gcc_assert (TREE_CODE (type) == REFERENCE_TYPE); |
471086d6 | 327 | |
c76251c1 | 328 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 329 | { |
ca106ab1 | 330 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
331 | here because it needs to live as long as DECL. */ | |
c76251c1 | 332 | tree targ = arg; |
ca106ab1 | 333 | |
5ab1aaca | 334 | arg = make_temporary_var_for_ref_to_temp (decl, target_type); |
c23ebfdd | 335 | |
336 | /* Process the initializer for the declaration. */ | |
38281c46 | 337 | DECL_INITIAL (arg) = targ; |
d91303a6 | 338 | cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE, |
011310f7 | 339 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 340 | } |
c76251c1 | 341 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
44189c16 | 342 | return get_target_expr_sfinae (arg, complain); |
1ad432f2 | 343 | |
ca106ab1 | 344 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 345 | address, transform all occurrences of the register, into a memory |
346 | reference we could win better. */ | |
44189c16 | 347 | rval = cp_build_addr_expr (arg, complain); |
15e55420 | 348 | if (rval == error_mark_node) |
349 | return error_mark_node; | |
350 | ||
6686e84d | 351 | if ((flags & LOOKUP_PROTECT) |
352 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
95397ff9 | 353 | && MAYBE_CLASS_TYPE_P (argtype) |
354 | && MAYBE_CLASS_TYPE_P (target_type)) | |
6686e84d | 355 | { |
7e6960e0 | 356 | /* We go through lookup_base for the access control. */ |
ae260dcc | 357 | tree binfo = lookup_base (argtype, target_type, ba_check, |
358 | NULL, complain); | |
6686e84d | 359 | if (binfo == error_mark_node) |
360 | return error_mark_node; | |
361 | if (binfo == NULL_TREE) | |
362 | return error_not_base_type (target_type, argtype); | |
c4698a21 | 363 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1, complain); |
6686e84d | 364 | } |
c76251c1 | 365 | else |
366 | rval | |
c4698a21 | 367 | = convert_to_pointer_force (build_pointer_type (target_type), |
368 | rval, complain); | |
8999978b | 369 | return build_nop (type, rval); |
471086d6 | 370 | } |
371 | ||
519ba62c | 372 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
373 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
374 | for diagnostics. | |
9031d10b | 375 | |
519ba62c | 376 | [dcl.init.ref] says that if an rvalue is used to |
377 | initialize a reference, then the reference must be to a | |
378 | non-volatile const type. */ | |
379 | ||
380 | static void | |
61f69bc9 | 381 | warn_ref_binding (location_t loc, tree reftype, tree intype, tree decl) |
519ba62c | 382 | { |
383 | tree ttl = TREE_TYPE (reftype); | |
9031d10b | 384 | |
519ba62c | 385 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) |
386 | { | |
387 | const char *msg; | |
388 | ||
389 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
ca82e026 | 390 | msg = G_("initialization of volatile reference type %q#T from " |
391 | "rvalue of type %qT"); | |
519ba62c | 392 | else if (CP_TYPE_VOLATILE_P (ttl)) |
ca82e026 | 393 | msg = G_("conversion to volatile reference type %q#T " |
394 | "from rvalue of type %qT"); | |
519ba62c | 395 | else if (decl) |
ca82e026 | 396 | msg = G_("initialization of non-const reference type %q#T from " |
397 | "rvalue of type %qT"); | |
519ba62c | 398 | else |
ca82e026 | 399 | msg = G_("conversion to non-const reference type %q#T from " |
400 | "rvalue of type %qT"); | |
519ba62c | 401 | |
61f69bc9 | 402 | permerror (loc, msg, reftype, intype); |
519ba62c | 403 | } |
404 | } | |
405 | ||
471086d6 | 406 | /* For C++: Only need to do one-level references, but cannot |
407 | get tripped up on signed/unsigned differences. | |
408 | ||
d81e00a4 | 409 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
410 | initialized. It can be error_mark_node if we don't know the _DECL but | |
411 | we know it's an initialization. */ | |
471086d6 | 412 | |
471086d6 | 413 | tree |
35771a9a | 414 | convert_to_reference (tree reftype, tree expr, int convtype, |
c4698a21 | 415 | int flags, tree decl, tsubst_flags_t complain) |
471086d6 | 416 | { |
cd16867a | 417 | tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); |
418 | tree intype; | |
471086d6 | 419 | tree rval = NULL_TREE; |
1a3f833b | 420 | tree rval_as_conversion = NULL_TREE; |
1bc16cab | 421 | bool can_convert_intype_to_type; |
61f69bc9 | 422 | location_t loc = EXPR_LOC_OR_HERE (expr); |
1a3f833b | 423 | |
9031d10b | 424 | if (TREE_CODE (type) == FUNCTION_TYPE |
d32df6a6 | 425 | && TREE_TYPE (expr) == unknown_type_node) |
66bbeb85 | 426 | expr = instantiate_type (type, expr, complain); |
0a3b29ad | 427 | |
428 | if (expr == error_mark_node) | |
429 | return error_mark_node; | |
430 | ||
431 | intype = TREE_TYPE (expr); | |
cc4d0855 | 432 | |
b4df430b | 433 | gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE); |
ab12ed55 | 434 | gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE); |
471086d6 | 435 | |
471086d6 | 436 | intype = TYPE_MAIN_VARIANT (intype); |
437 | ||
66bbeb85 | 438 | can_convert_intype_to_type = can_convert (type, intype, complain); |
439 | ||
1bc16cab | 440 | if (!can_convert_intype_to_type |
95397ff9 | 441 | && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype) |
1a3f833b | 442 | && ! (flags & LOOKUP_NO_CONVERSION)) |
443 | { | |
444 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
445 | ||
0a4be248 | 446 | rval_as_conversion |
8999978b | 447 | = build_type_conversion (reftype, expr); |
1a3f833b | 448 | |
449 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
450 | && real_lvalue_p (rval_as_conversion)) | |
451 | { | |
452 | expr = rval_as_conversion; | |
453 | rval_as_conversion = NULL_TREE; | |
454 | intype = type; | |
1bc16cab | 455 | can_convert_intype_to_type = 1; |
1a3f833b | 456 | } |
457 | } | |
458 | ||
66bbeb85 | 459 | if (((convtype & CONV_STATIC) && can_convert (intype, type, complain)) |
1bc16cab | 460 | || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type)) |
471086d6 | 461 | { |
c4698a21 | 462 | { |
463 | tree ttl = TREE_TYPE (reftype); | |
464 | tree ttr = lvalue_type (expr); | |
471086d6 | 465 | |
c4698a21 | 466 | if ((complain & tf_warning) |
467 | && ! real_lvalue_p (expr)) | |
468 | warn_ref_binding (loc, reftype, intype, decl); | |
9031d10b | 469 | |
c4698a21 | 470 | if (! (convtype & CONV_CONST) |
471 | && !at_least_as_qualified_p (ttl, ttr)) | |
472 | { | |
473 | if (complain & tf_error) | |
474 | permerror (loc, "conversion from %qT to %qT discards qualifiers", | |
475 | ttr, reftype); | |
476 | else | |
477 | return error_mark_node; | |
478 | } | |
479 | } | |
0543e7a9 | 480 | |
c4698a21 | 481 | return build_up_reference (reftype, expr, flags, decl, complain); |
471086d6 | 482 | } |
c07b1ad1 | 483 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 484 | { |
485 | /* When casting an lvalue to a reference type, just convert into | |
486 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 487 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 488 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 489 | |
3748625f | 490 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
653e5405 | 491 | meant. */ |
c4698a21 | 492 | if ((complain & tf_warning) |
493 | && TREE_CODE (intype) == POINTER_TYPE | |
a09db423 | 494 | && (comptypes (TREE_TYPE (intype), type, |
495 | COMPARE_BASE | COMPARE_DERIVED))) | |
61f69bc9 | 496 | warning_at (loc, 0, "casting %qT to %qT does not dereference pointer", |
497 | intype, reftype); | |
9031d10b | 498 | |
c4698a21 | 499 | rval = cp_build_addr_expr (expr, complain); |
0543e7a9 | 500 | if (rval != error_mark_node) |
985e9ee0 | 501 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
c4698a21 | 502 | rval, 0, complain); |
0543e7a9 | 503 | if (rval != error_mark_node) |
b0722fac | 504 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 505 | } |
0a4be248 | 506 | else |
860740a7 | 507 | { |
508 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
c4698a21 | 509 | ICR_CONVERTING, 0, 0, complain); |
a66fe4cb | 510 | if (rval == NULL_TREE || rval == error_mark_node) |
511 | return rval; | |
c4698a21 | 512 | if (complain & tf_warning) |
513 | warn_ref_binding (loc, reftype, intype, decl); | |
514 | rval = build_up_reference (reftype, rval, flags, decl, complain); | |
860740a7 | 515 | } |
471086d6 | 516 | |
517 | if (rval) | |
518 | { | |
96624a9e | 519 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 520 | return rval; |
521 | } | |
522 | ||
c4698a21 | 523 | if (complain & tf_error) |
61f69bc9 | 524 | error_at (loc, "cannot convert type %qT to type %qT", intype, reftype); |
b248d3f7 | 525 | |
471086d6 | 526 | return error_mark_node; |
527 | } | |
528 | ||
529 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 530 | way down to its lowest form. */ |
531 | ||
471086d6 | 532 | tree |
35771a9a | 533 | convert_from_reference (tree val) |
471086d6 | 534 | { |
73bdcca2 | 535 | if (TREE_TYPE (val) |
536 | && TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE) | |
729f89ff | 537 | { |
2fb61329 | 538 | tree t = TREE_TYPE (TREE_TYPE (val)); |
729f89ff | 539 | tree ref = build1 (INDIRECT_REF, t, val); |
9031d10b | 540 | |
3d37a176 | 541 | mark_exp_read (val); |
729f89ff | 542 | /* We *must* set TREE_READONLY when dereferencing a pointer to const, |
543 | so that we get the proper error message if the result is used | |
544 | to assign to. Also, &* is supposed to be a no-op. */ | |
545 | TREE_READONLY (ref) = CP_TYPE_CONST_P (t); | |
546 | TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); | |
547 | TREE_SIDE_EFFECTS (ref) | |
548 | = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val)); | |
729f89ff | 549 | val = ref; |
550 | } | |
9031d10b | 551 | |
471086d6 | 552 | return val; |
553 | } | |
e5dab226 | 554 | |
555 | /* Really perform an lvalue-to-rvalue conversion, including copying an | |
556 | argument of class type into a temporary. */ | |
557 | ||
558 | tree | |
9e505437 | 559 | force_rvalue (tree expr, tsubst_flags_t complain) |
e5dab226 | 560 | { |
9e505437 | 561 | tree type = TREE_TYPE (expr); |
562 | if (MAYBE_CLASS_TYPE_P (type) && TREE_CODE (expr) != TARGET_EXPR) | |
563 | { | |
564 | VEC(tree,gc) *args = make_tree_vector_single (expr); | |
565 | expr = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
566 | &args, type, LOOKUP_NORMAL, complain); | |
567 | release_tree_vector (args); | |
568 | expr = build_cplus_new (type, expr, complain); | |
569 | } | |
e5dab226 | 570 | else |
4405c1ad | 571 | expr = decay_conversion (expr, complain); |
e5dab226 | 572 | |
573 | return expr; | |
574 | } | |
f5220369 | 575 | |
471086d6 | 576 | \f |
a1f05651 | 577 | /* If EXPR and ORIG are INTEGER_CSTs, return a version of EXPR that has |
578 | TREE_OVERFLOW set only if it is set in ORIG. Otherwise, return EXPR | |
579 | unchanged. */ | |
580 | ||
581 | static tree | |
582 | ignore_overflows (tree expr, tree orig) | |
583 | { | |
584 | if (TREE_CODE (expr) == INTEGER_CST | |
585 | && TREE_CODE (orig) == INTEGER_CST | |
586 | && TREE_OVERFLOW (expr) != TREE_OVERFLOW (orig)) | |
587 | { | |
588 | gcc_assert (!TREE_OVERFLOW (orig)); | |
589 | /* Ensure constant sharing. */ | |
590 | expr = build_int_cst_wide (TREE_TYPE (expr), | |
591 | TREE_INT_CST_LOW (expr), | |
592 | TREE_INT_CST_HIGH (expr)); | |
593 | } | |
594 | return expr; | |
595 | } | |
596 | ||
597 | /* Fold away simple conversions, but make sure TREE_OVERFLOW is set | |
598 | properly. */ | |
f5220369 | 599 | |
600 | tree | |
601 | cp_fold_convert (tree type, tree expr) | |
602 | { | |
a1f05651 | 603 | tree conv = fold_convert (type, expr); |
604 | conv = ignore_overflows (conv, expr); | |
605 | return conv; | |
f5220369 | 606 | } |
607 | ||
c4a8ac95 | 608 | /* C++ conversions, preference to static cast conversions. */ |
609 | ||
610 | tree | |
c4698a21 | 611 | cp_convert (tree type, tree expr, tsubst_flags_t complain) |
c4a8ac95 | 612 | { |
c4698a21 | 613 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL, complain); |
c4a8ac95 | 614 | } |
615 | ||
59dd8856 | 616 | /* C++ equivalent of convert_and_check but using cp_convert as the |
617 | conversion function. | |
618 | ||
619 | Convert EXPR to TYPE, warning about conversion problems with constants. | |
620 | Invoke this function on every expression that is converted implicitly, | |
621 | i.e. because of language rules and not because of an explicit cast. */ | |
622 | ||
623 | tree | |
c4698a21 | 624 | cp_convert_and_check (tree type, tree expr, tsubst_flags_t complain) |
59dd8856 | 625 | { |
626 | tree result; | |
627 | ||
628 | if (TREE_TYPE (expr) == type) | |
629 | return expr; | |
630 | ||
c4698a21 | 631 | result = cp_convert (type, expr, complain); |
59dd8856 | 632 | |
c4698a21 | 633 | if ((complain & tf_warning) |
634 | && c_inhibit_evaluation_warnings == 0 | |
48d94ede | 635 | && !TREE_OVERFLOW_P (expr) |
636 | && result != error_mark_node) | |
59dd8856 | 637 | warnings_for_convert_and_check (type, expr, result); |
638 | ||
639 | return result; | |
640 | } | |
641 | ||
b248d3f7 | 642 | /* Conversion... |
643 | ||
644 | FLAGS indicates how we should behave. */ | |
645 | ||
471086d6 | 646 | tree |
c4698a21 | 647 | ocp_convert (tree type, tree expr, int convtype, int flags, |
648 | tsubst_flags_t complain) | |
471086d6 | 649 | { |
cd16867a | 650 | tree e = expr; |
651 | enum tree_code code = TREE_CODE (type); | |
7a979707 | 652 | const char *invalid_conv_diag; |
2b3c93a3 | 653 | tree e1; |
61f69bc9 | 654 | location_t loc = EXPR_LOC_OR_HERE (expr); |
471086d6 | 655 | |
1bc16cab | 656 | if (error_operand_p (e) || type == error_mark_node) |
471086d6 | 657 | return error_mark_node; |
d81e00a4 | 658 | |
5b592939 | 659 | complete_type (type); |
660 | complete_type (TREE_TYPE (expr)); | |
661 | ||
7a979707 | 662 | if ((invalid_conv_diag |
663 | = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
664 | { | |
c4698a21 | 665 | if (complain & tf_error) |
666 | error (invalid_conv_diag); | |
7a979707 | 667 | return error_mark_node; |
668 | } | |
669 | ||
ce984e5e | 670 | /* FIXME remove when moving to c_fully_fold model. */ |
671 | /* FIXME do we still need this test? */ | |
672 | if (!CLASS_TYPE_P (type)) | |
673 | e = integral_constant_value (e); | |
7a00f939 | 674 | if (error_operand_p (e)) |
675 | return error_mark_node; | |
7745052b | 676 | |
95397ff9 | 677 | if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP)) |
1a3f833b | 678 | /* We need a new temporary; don't take this shortcut. */; |
930e8175 | 679 | else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e))) |
ca23ec64 | 680 | { |
daf9ff67 | 681 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 682 | /* The call to fold will not always remove the NOP_EXPR as |
683 | might be expected, since if one of the types is a typedef; | |
755edffd | 684 | the comparison in fold is just equality of pointers, not a |
a09db423 | 685 | call to comptypes. We don't call fold in this case because |
f699c174 | 686 | that can result in infinite recursion; fold will call |
687 | convert, which will call ocp_convert, etc. */ | |
688 | return e; | |
372e0e29 | 689 | /* For complex data types, we need to perform componentwise |
653e5405 | 690 | conversion. */ |
372e0e29 | 691 | else if (TREE_CODE (type) == COMPLEX_TYPE) |
653e5405 | 692 | return fold_if_not_in_template (convert_to_complex (type, e)); |
bdb2219e | 693 | else if (TREE_CODE (e) == TARGET_EXPR) |
694 | { | |
695 | /* Don't build a NOP_EXPR of class type. Instead, change the | |
930e8175 | 696 | type of the temporary. */ |
bdb2219e | 697 | TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type; |
698 | return e; | |
699 | } | |
ca23ec64 | 700 | else |
092b1d6f | 701 | { |
702 | /* We shouldn't be treating objects of ADDRESSABLE type as | |
703 | rvalues. */ | |
704 | gcc_assert (!TREE_ADDRESSABLE (type)); | |
5d7ed6c7 | 705 | return fold_if_not_in_template (build_nop (type, e)); |
092b1d6f | 706 | } |
ca23ec64 | 707 | } |
708 | ||
2b3c93a3 | 709 | e1 = targetm.convert_to_type (type, e); |
710 | if (e1) | |
711 | return e1; | |
712 | ||
d81e00a4 | 713 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 714 | { |
c4698a21 | 715 | e = convert_to_void (e, ICV_CAST, complain); |
aeef2be5 | 716 | return e; |
95b2ac55 | 717 | } |
d81e00a4 | 718 | |
bb0726a1 | 719 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 720 | { |
617abf06 | 721 | tree intype = TREE_TYPE (e); |
a1f05651 | 722 | tree converted; |
384590d4 | 723 | |
724 | if (TREE_CODE (type) == ENUMERAL_TYPE) | |
725 | { | |
726 | /* enum = enum, enum = int, enum = float, (enum)pointer are all | |
727 | errors. */ | |
728 | if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype) | |
653e5405 | 729 | || TREE_CODE (intype) == REAL_TYPE) |
b312a686 | 730 | && ! (convtype & CONV_STATIC)) |
384590d4 | 731 | || TREE_CODE (intype) == POINTER_TYPE) |
732 | { | |
c4698a21 | 733 | if (complain & tf_error) |
61f69bc9 | 734 | permerror (loc, "conversion from %q#T to %q#T", intype, type); |
c4698a21 | 735 | else |
384590d4 | 736 | return error_mark_node; |
737 | } | |
738 | ||
739 | /* [expr.static.cast] | |
740 | ||
741 | 8. A value of integral or enumeration type can be explicitly | |
742 | converted to an enumeration type. The value is unchanged if | |
743 | the original value is within the range of the enumeration | |
744 | values. Otherwise, the resulting enumeration value is | |
745 | unspecified. */ | |
c4698a21 | 746 | if ((complain & tf_warning) |
c28ddc97 | 747 | && TREE_CODE (e) == INTEGER_CST |
748 | && !int_fits_type_p (e, ENUM_UNDERLYING_TYPE (type))) | |
61f69bc9 | 749 | warning_at (loc, OPT_Wconversion, |
750 | "the result of the conversion is unspecified because " | |
751 | "%qE is outside the range of type %qT", | |
752 | expr, type); | |
471086d6 | 753 | } |
95397ff9 | 754 | if (MAYBE_CLASS_TYPE_P (intype)) |
471086d6 | 755 | { |
756 | tree rval; | |
8999978b | 757 | rval = build_type_conversion (type, e); |
6495357a | 758 | if (rval) |
759 | return rval; | |
c4698a21 | 760 | if (complain & tf_error) |
61f69bc9 | 761 | error_at (loc, "%q#T used where a %qT was expected", intype, type); |
471086d6 | 762 | return error_mark_node; |
763 | } | |
bb0726a1 | 764 | if (code == BOOLEAN_TYPE) |
f8913d47 | 765 | { |
61f69bc9 | 766 | if (TREE_CODE (intype) == VOID_TYPE) |
767 | { | |
c4698a21 | 768 | if (complain & tf_error) |
769 | error_at (loc, | |
770 | "could not convert %qE from %<void%> to %<bool%>", | |
771 | expr); | |
61f69bc9 | 772 | return error_mark_node; |
773 | } | |
774 | ||
f8913d47 | 775 | /* We can't implicitly convert a scoped enum to bool, so convert |
776 | to the underlying type first. */ | |
777 | if (SCOPED_ENUM_P (intype) && (convtype & CONV_STATIC)) | |
172fff7b | 778 | e = build_nop (ENUM_UNDERLYING_TYPE (intype), e); |
f8913d47 | 779 | return cp_truthvalue_conversion (e); |
780 | } | |
ce871053 | 781 | |
a1f05651 | 782 | converted = fold_if_not_in_template (convert_to_integer (type, e)); |
783 | ||
784 | /* Ignore any integer overflow caused by the conversion. */ | |
785 | return ignore_overflows (converted, e); | |
471086d6 | 786 | } |
c7ca48ea | 787 | if (NULLPTR_TYPE_P (type) && e && null_ptr_cst_p (e)) |
6fe11077 | 788 | return nullptr_node; |
05765a91 | 789 | if (POINTER_TYPE_P (type) || TYPE_PTRMEM_P (type)) |
c4698a21 | 790 | return fold_if_not_in_template (cp_convert_to_pointer (type, e, complain)); |
684b9d79 | 791 | if (code == VECTOR_TYPE) |
c37ff371 | 792 | { |
793 | tree in_vtype = TREE_TYPE (e); | |
95397ff9 | 794 | if (MAYBE_CLASS_TYPE_P (in_vtype)) |
c37ff371 | 795 | { |
796 | tree ret_val; | |
797 | ret_val = build_type_conversion (type, e); | |
653e5405 | 798 | if (ret_val) |
799 | return ret_val; | |
c4698a21 | 800 | if (complain & tf_error) |
801 | error_at (loc, "%q#T used where a %qT was expected", | |
802 | in_vtype, type); | |
653e5405 | 803 | return error_mark_node; |
c37ff371 | 804 | } |
5d7ed6c7 | 805 | return fold_if_not_in_template (convert_to_vector (type, e)); |
c37ff371 | 806 | } |
c4a8ac95 | 807 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 808 | { |
95397ff9 | 809 | if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e))) |
471086d6 | 810 | { |
811 | tree rval; | |
8999978b | 812 | rval = build_type_conversion (type, e); |
471086d6 | 813 | if (rval) |
814 | return rval; | |
c4698a21 | 815 | else if (complain & tf_error) |
816 | error_at (loc, | |
817 | "%q#T used where a floating point value was expected", | |
818 | TREE_TYPE (e)); | |
471086d6 | 819 | } |
c4a8ac95 | 820 | if (code == REAL_TYPE) |
5d7ed6c7 | 821 | return fold_if_not_in_template (convert_to_real (type, e)); |
c4a8ac95 | 822 | else if (code == COMPLEX_TYPE) |
5d7ed6c7 | 823 | return fold_if_not_in_template (convert_to_complex (type, e)); |
471086d6 | 824 | } |
825 | ||
826 | /* New C++ semantics: since assignment is now based on | |
827 | memberwise copying, if the rhs type is derived from the | |
828 | lhs type, then we may still do a conversion. */ | |
95397ff9 | 829 | if (RECORD_OR_UNION_CODE_P (code)) |
471086d6 | 830 | { |
831 | tree dtype = TREE_TYPE (e); | |
c25194fd | 832 | tree ctor = NULL_TREE; |
471086d6 | 833 | |
471086d6 | 834 | dtype = TYPE_MAIN_VARIANT (dtype); |
835 | ||
471086d6 | 836 | /* Conversion between aggregate types. New C++ semantics allow |
837 | objects of derived type to be cast to objects of base type. | |
838 | Old semantics only allowed this between pointers. | |
839 | ||
840 | There may be some ambiguity between using a constructor | |
841 | vs. using a type conversion operator when both apply. */ | |
842 | ||
0a4be248 | 843 | ctor = e; |
860740a7 | 844 | |
44189c16 | 845 | if (abstract_virtuals_error_sfinae (NULL_TREE, type, complain)) |
8c18e707 | 846 | return error_mark_node; |
6cbb4197 | 847 | |
f82f1250 | 848 | if (BRACE_ENCLOSED_INITIALIZER_P (ctor)) |
c4698a21 | 849 | ctor = perform_implicit_conversion (type, ctor, complain); |
f82f1250 | 850 | else if ((flags & LOOKUP_ONLYCONVERTING) |
851 | && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 852 | /* For copy-initialization, first we create a temp of the proper type |
853 | with a user-defined conversion sequence, then we direct-initialize | |
854 | the target with the temp (see [dcl.init]). */ | |
c4698a21 | 855 | ctor = build_user_type_conversion (type, ctor, flags, complain); |
3eb89cd8 | 856 | else |
f352a3fb | 857 | { |
858 | VEC(tree,gc) *ctor_vec = make_tree_vector_single (ctor); | |
859 | ctor = build_special_member_call (NULL_TREE, | |
860 | complete_ctor_identifier, | |
861 | &ctor_vec, | |
c4698a21 | 862 | type, flags, complain); |
f352a3fb | 863 | release_tree_vector (ctor_vec); |
864 | } | |
0a4be248 | 865 | if (ctor) |
c4698a21 | 866 | return build_cplus_new (type, ctor, complain); |
471086d6 | 867 | } |
868 | ||
c4698a21 | 869 | if (complain & tf_error) |
a7cc1549 | 870 | { |
871 | /* If the conversion failed and expr was an invalid use of pointer to | |
872 | member function, try to report a meaningful error. */ | |
c4698a21 | 873 | if (invalid_nonstatic_memfn_p (expr, complain)) |
a7cc1549 | 874 | /* We displayed the error message. */; |
875 | else | |
61f69bc9 | 876 | error_at (loc, "conversion from %qT to non-scalar type %qT requested", |
877 | TREE_TYPE (expr), type); | |
a7cc1549 | 878 | } |
471086d6 | 879 | return error_mark_node; |
880 | } | |
881 | ||
b1a8d4ce | 882 | /* When an expression is used in a void context, its value is discarded and |
883 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
884 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
885 | in a void context. The C++ standard does not define what an `access' to an | |
63eff20d | 886 | object is, but there is reason to believe that it is the lvalue to rvalue |
b1a8d4ce | 887 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it |
888 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
889 | indicates that volatile semantics should be the same between C and C++ | |
890 | where ever possible. C leaves it implementation defined as to what | |
891 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
892 | the volatile object `vp' points to, unless that is an incomplete type. For | |
893 | volatile references we do not do this interpretation, because that would | |
894 | make it impossible to ignore the reference return value from functions. We | |
895 | issue warnings in the confusing cases. | |
9031d10b | 896 | |
dab3247a | 897 | The IMPLICIT is ICV_CAST when the user is explicitly converting an expression |
898 | to void via a cast. If an expression is being implicitly converted, IMPLICIT | |
899 | indicates the context of the implicit conversion. */ | |
b1a8d4ce | 900 | |
901 | tree | |
dab3247a | 902 | convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain) |
b1a8d4ce | 903 | { |
61f69bc9 | 904 | location_t loc = EXPR_LOC_OR_HERE (expr); |
905 | ||
9031d10b | 906 | if (expr == error_mark_node |
3d411d73 | 907 | || TREE_TYPE (expr) == error_mark_node) |
908 | return error_mark_node; | |
b2af2a93 | 909 | |
dab3247a | 910 | if (implicit == ICV_CAST) |
f94341bb | 911 | mark_exp_read (expr); |
912 | else | |
913 | { | |
914 | tree exprv = expr; | |
915 | ||
916 | while (TREE_CODE (exprv) == COMPOUND_EXPR) | |
917 | exprv = TREE_OPERAND (exprv, 1); | |
0388391d | 918 | if (DECL_P (exprv) |
919 | || handled_component_p (exprv) | |
920 | || TREE_CODE (exprv) == INDIRECT_REF) | |
f94341bb | 921 | /* Expr is not being 'used' here, otherwise we whould have |
922 | called mark_{rl}value_use use here, which would have in turn | |
923 | called mark_exp_read. Rather, we call mark_exp_read directly | |
924 | to avoid some warnings when | |
925 | -Wunused-but-set-{variable,parameter} is in effect. */ | |
926 | mark_exp_read (exprv); | |
927 | } | |
b2af2a93 | 928 | |
b1a8d4ce | 929 | if (!TREE_TYPE (expr)) |
930 | return expr; | |
ebd21de4 | 931 | if (invalid_nonstatic_memfn_p (expr, complain)) |
334f6ce1 | 932 | return error_mark_node; |
ed36f1cf | 933 | if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR) |
934 | { | |
ebd21de4 | 935 | if (complain & tf_error) |
61f69bc9 | 936 | error_at (loc, "pseudo-destructor is not called"); |
ed36f1cf | 937 | return error_mark_node; |
938 | } | |
e3cfe3ce | 939 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 940 | return expr; |
941 | switch (TREE_CODE (expr)) | |
942 | { | |
943 | case COND_EXPR: | |
944 | { | |
653e5405 | 945 | /* The two parts of a cond expr might be separate lvalues. */ |
946 | tree op1 = TREE_OPERAND (expr,1); | |
947 | tree op2 = TREE_OPERAND (expr,2); | |
527facbb | 948 | bool side_effects = ((op1 && TREE_SIDE_EFFECTS (op1)) |
949 | || TREE_SIDE_EFFECTS (op2)); | |
dab3247a | 950 | tree new_op1, new_op2; |
527facbb | 951 | new_op1 = NULL_TREE; |
dab3247a | 952 | if (implicit != ICV_CAST && !side_effects) |
953 | { | |
527facbb | 954 | if (op1) |
955 | new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain); | |
dab3247a | 956 | new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain); |
957 | } | |
958 | else | |
959 | { | |
527facbb | 960 | if (op1) |
961 | new_op1 = convert_to_void (op1, ICV_CAST, complain); | |
dab3247a | 962 | new_op2 = convert_to_void (op2, ICV_CAST, complain); |
963 | } | |
9031d10b | 964 | |
527facbb | 965 | expr = build3 (COND_EXPR, TREE_TYPE (new_op2), |
831d52a2 | 966 | TREE_OPERAND (expr, 0), new_op1, new_op2); |
653e5405 | 967 | break; |
b1a8d4ce | 968 | } |
9031d10b | 969 | |
b1a8d4ce | 970 | case COMPOUND_EXPR: |
971 | { | |
653e5405 | 972 | /* The second part of a compound expr contains the value. */ |
973 | tree op1 = TREE_OPERAND (expr,1); | |
dab3247a | 974 | tree new_op1; |
975 | if (implicit != ICV_CAST && !TREE_NO_WARNING (expr)) | |
976 | new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain); | |
977 | else | |
978 | new_op1 = convert_to_void (op1, ICV_CAST, complain); | |
9031d10b | 979 | |
653e5405 | 980 | if (new_op1 != op1) |
e907a2e9 | 981 | { |
831d52a2 | 982 | tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1), |
983 | TREE_OPERAND (expr, 0), new_op1); | |
e907a2e9 | 984 | expr = t; |
985 | } | |
986 | ||
653e5405 | 987 | break; |
b1a8d4ce | 988 | } |
9031d10b | 989 | |
b1a8d4ce | 990 | case NON_LVALUE_EXPR: |
991 | case NOP_EXPR: | |
c0af329c | 992 | /* These have already decayed to rvalue. */ |
b1a8d4ce | 993 | break; |
9031d10b | 994 | |
331bc0ad | 995 | case CALL_EXPR: /* We have a special meaning for volatile void fn(). */ |
b1a8d4ce | 996 | break; |
9031d10b | 997 | |
b1a8d4ce | 998 | case INDIRECT_REF: |
999 | { | |
653e5405 | 1000 | tree type = TREE_TYPE (expr); |
1001 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
1002 | == REFERENCE_TYPE; | |
1003 | int is_volatile = TYPE_VOLATILE (type); | |
1004 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
1005 | ||
dc02da7f | 1006 | /* Can't load the value if we don't know the type. */ |
653e5405 | 1007 | if (is_volatile && !is_complete) |
ebd21de4 | 1008 | { |
1009 | if (complain & tf_warning) | |
dab3247a | 1010 | switch (implicit) |
1011 | { | |
1012 | case ICV_CAST: | |
61f69bc9 | 1013 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1014 | "object of incomplete type %qT", type); |
1015 | break; | |
1016 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1017 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1018 | "incomplete type %qT in second operand " |
1019 | "of conditional expression", type); | |
1020 | break; | |
1021 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1022 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1023 | "incomplete type %qT in third operand " |
1024 | "of conditional expression", type); | |
1025 | break; | |
1026 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1027 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1028 | "incomplete type %qT in right operand of " |
1029 | "comma operator", type); | |
1030 | break; | |
1031 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1032 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1033 | "incomplete type %qT in left operand of " |
1034 | "comma operator", type); | |
1035 | break; | |
1036 | case ICV_STATEMENT: | |
61f69bc9 | 1037 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1038 | "incomplete type %qT in statement", type); |
1039 | break; | |
1040 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1041 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1042 | "incomplete type %qT in for increment " |
1043 | "expression", type); | |
1044 | break; | |
1045 | default: | |
1046 | gcc_unreachable (); | |
1047 | } | |
ebd21de4 | 1048 | } |
dc02da7f | 1049 | /* Don't load the value if this is an implicit dereference, or if |
1050 | the type needs to be handled by ctors/dtors. */ | |
dab3247a | 1051 | else if (is_volatile && is_reference) |
ebd21de4 | 1052 | { |
1053 | if (complain & tf_warning) | |
dab3247a | 1054 | switch (implicit) |
1055 | { | |
1056 | case ICV_CAST: | |
61f69bc9 | 1057 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1058 | "object of type %qT", type); |
1059 | break; | |
1060 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1061 | warning_at (loc, 0, "implicit dereference will not access " |
1062 | "object of type %qT in second operand of " | |
dab3247a | 1063 | "conditional expression", type); |
1064 | break; | |
1065 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1066 | warning_at (loc, 0, "implicit dereference will not access " |
1067 | "object of type %qT in third operand of " | |
dab3247a | 1068 | "conditional expression", type); |
1069 | break; | |
1070 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1071 | warning_at (loc, 0, "implicit dereference will not access " |
1072 | "object of type %qT in right operand of " | |
dab3247a | 1073 | "comma operator", type); |
1074 | break; | |
1075 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1076 | warning_at (loc, 0, "implicit dereference will not access " |
1077 | "object of type %qT in left operand of comma " | |
1078 | "operator", type); | |
dab3247a | 1079 | break; |
1080 | case ICV_STATEMENT: | |
61f69bc9 | 1081 | warning_at (loc, 0, "implicit dereference will not access " |
1082 | "object of type %qT in statement", type); | |
dab3247a | 1083 | break; |
1084 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1085 | warning_at (loc, 0, "implicit dereference will not access " |
1086 | "object of type %qT in for increment expression", | |
1087 | type); | |
dab3247a | 1088 | break; |
1089 | default: | |
1090 | gcc_unreachable (); | |
1091 | } | |
ebd21de4 | 1092 | } |
dab3247a | 1093 | else if (is_volatile && TREE_ADDRESSABLE (type)) |
1094 | { | |
1095 | if (complain & tf_warning) | |
1096 | switch (implicit) | |
1097 | { | |
1098 | case ICV_CAST: | |
61f69bc9 | 1099 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1100 | "object of non-trivially-copyable type %qT", |
61f69bc9 | 1101 | type); |
dab3247a | 1102 | break; |
1103 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1104 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1105 | "non-trivially-copyable type %qT in second " |
1106 | "operand of conditional expression", type); | |
1107 | break; | |
1108 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1109 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1110 | "non-trivially-copyable type %qT in third " |
1111 | "operand of conditional expression", type); | |
1112 | break; | |
1113 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1114 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1115 | "non-trivially-copyable type %qT in right " |
1116 | "operand of comma operator", type); | |
1117 | break; | |
1118 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1119 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1120 | "non-trivially-copyable type %qT in left " |
1121 | "operand of comma operator", type); | |
1122 | break; | |
1123 | case ICV_STATEMENT: | |
61f69bc9 | 1124 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1125 | "non-trivially-copyable type %qT in statement", |
61f69bc9 | 1126 | type); |
dab3247a | 1127 | break; |
1128 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1129 | warning_at (loc, 0, "indirection will not access object of " |
dab3247a | 1130 | "non-trivially-copyable type %qT in for " |
1131 | "increment expression", type); | |
1132 | break; | |
1133 | default: | |
1134 | gcc_unreachable (); | |
1135 | } | |
1136 | } | |
dc02da7f | 1137 | if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type)) |
a4d4030b | 1138 | { |
1139 | /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF | |
1140 | operation is stripped off. Note that we don't warn about | |
1141 | - an expression with TREE_NO_WARNING set. (For an example of | |
1142 | such expressions, see build_over_call in call.c.) | |
1143 | - automatic dereferencing of references, since the user cannot | |
3d177e8c | 1144 | control it. (See also warn_if_unused_value() in c-common.c.) */ |
a4d4030b | 1145 | if (warn_unused_value |
dab3247a | 1146 | && implicit != ICV_CAST |
a4d4030b | 1147 | && (complain & tf_warning) |
1148 | && !TREE_NO_WARNING (expr) | |
1149 | && !is_reference) | |
61f69bc9 | 1150 | warning_at (loc, OPT_Wunused_value, "value computed is not used"); |
a4d4030b | 1151 | expr = TREE_OPERAND (expr, 0); |
1152 | } | |
653e5405 | 1153 | |
1154 | break; | |
b1a8d4ce | 1155 | } |
9031d10b | 1156 | |
b1a8d4ce | 1157 | case VAR_DECL: |
1158 | { | |
653e5405 | 1159 | /* External variables might be incomplete. */ |
1160 | tree type = TREE_TYPE (expr); | |
1161 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
1162 | ||
ebd21de4 | 1163 | if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning)) |
dab3247a | 1164 | switch (implicit) |
1165 | { | |
1166 | case ICV_CAST: | |
61f69bc9 | 1167 | warning_at (loc, 0, "conversion to void will not access " |
dab3247a | 1168 | "object %qE of incomplete type %qT", expr, type); |
1169 | break; | |
1170 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1171 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1172 | "not be accessed in second operand of " | |
dab3247a | 1173 | "conditional expression", expr, type); |
1174 | break; | |
1175 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1176 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1177 | "not be accessed in third operand of " | |
dab3247a | 1178 | "conditional expression", expr, type); |
1179 | break; | |
1180 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1181 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1182 | "not be accessed in right operand of comma operator", | |
1183 | expr, type); | |
dab3247a | 1184 | break; |
1185 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1186 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1187 | "not be accessed in left operand of comma operator", | |
1188 | expr, type); | |
dab3247a | 1189 | break; |
1190 | case ICV_STATEMENT: | |
61f69bc9 | 1191 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1192 | "not be accessed in statement", expr, type); | |
dab3247a | 1193 | break; |
1194 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1195 | warning_at (loc, 0, "variable %qE of incomplete type %qT will " |
1196 | "not be accessed in for increment expression", | |
1197 | expr, type); | |
dab3247a | 1198 | break; |
1199 | default: | |
1200 | gcc_unreachable (); | |
1201 | } | |
1202 | ||
653e5405 | 1203 | break; |
b1a8d4ce | 1204 | } |
d9f88785 | 1205 | |
25b3017b | 1206 | case TARGET_EXPR: |
1207 | /* Don't bother with the temporary object returned from a function if | |
1208 | we don't use it and don't need to destroy it. We'll still | |
1209 | allocate space for it in expand_call or declare_return_variable, | |
1210 | but we don't need to track it through all the tree phases. */ | |
67bb1301 | 1211 | if (TARGET_EXPR_IMPLICIT_P (expr) |
25b3017b | 1212 | && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr))) |
1213 | { | |
1214 | tree init = TARGET_EXPR_INITIAL (expr); | |
1215 | if (TREE_CODE (init) == AGGR_INIT_EXPR | |
1216 | && !AGGR_INIT_VIA_CTOR_P (init)) | |
1217 | { | |
c2f47e15 | 1218 | tree fn = AGGR_INIT_EXPR_FN (init); |
389dd41b | 1219 | expr = build_call_array_loc (input_location, |
1220 | TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))), | |
1221 | fn, | |
1222 | aggr_init_expr_nargs (init), | |
1223 | AGGR_INIT_EXPR_ARGP (init)); | |
25b3017b | 1224 | } |
1225 | } | |
1226 | break; | |
1227 | ||
b1a8d4ce | 1228 | default:; |
1229 | } | |
eebd67e7 | 1230 | expr = resolve_nondeduced_context (expr); |
b1a8d4ce | 1231 | { |
1232 | tree probe = expr; | |
9031d10b | 1233 | |
b1a8d4ce | 1234 | if (TREE_CODE (probe) == ADDR_EXPR) |
1235 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 1236 | if (type_unknown_p (probe)) |
1237 | { | |
1238 | /* [over.over] enumerates the places where we can take the address | |
1239 | of an overloaded function, and this is not one of them. */ | |
ebd21de4 | 1240 | if (complain & tf_error) |
dab3247a | 1241 | switch (implicit) |
1242 | { | |
1243 | case ICV_CAST: | |
61f69bc9 | 1244 | error_at (loc, "conversion to void " |
1245 | "cannot resolve address of overloaded function"); | |
dab3247a | 1246 | break; |
1247 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1248 | error_at (loc, "second operand of conditional expression " |
1249 | "cannot resolve address of overloaded function"); | |
dab3247a | 1250 | break; |
1251 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1252 | error_at (loc, "third operand of conditional expression " |
1253 | "cannot resolve address of overloaded function"); | |
dab3247a | 1254 | break; |
1255 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1256 | error_at (loc, "right operand of comma operator " |
1257 | "cannot resolve address of overloaded function"); | |
dab3247a | 1258 | break; |
1259 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1260 | error_at (loc, "left operand of comma operator " |
1261 | "cannot resolve address of overloaded function"); | |
dab3247a | 1262 | break; |
1263 | case ICV_STATEMENT: | |
61f69bc9 | 1264 | error_at (loc, "statement " |
1265 | "cannot resolve address of overloaded function"); | |
dab3247a | 1266 | break; |
1267 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1268 | error_at (loc, "for increment expression " |
1269 | "cannot resolve address of overloaded function"); | |
dab3247a | 1270 | break; |
1271 | } | |
ebd21de4 | 1272 | else |
1273 | return error_mark_node; | |
ea720917 | 1274 | expr = void_zero_node; |
2e0e6579 | 1275 | } |
dab3247a | 1276 | else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe)) |
2056769e | 1277 | { |
1278 | /* Only warn when there is no &. */ | |
ebd21de4 | 1279 | if (complain & tf_warning) |
dab3247a | 1280 | switch (implicit) |
1281 | { | |
1282 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1283 | warning_at (loc, OPT_Waddress, |
1284 | "second operand of conditional expression " | |
1285 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1286 | break; |
1287 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1288 | warning_at (loc, OPT_Waddress, |
1289 | "third operand of conditional expression " | |
1290 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1291 | break; |
1292 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1293 | warning_at (loc, OPT_Waddress, |
1294 | "right operand of comma operator " | |
1295 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1296 | break; |
1297 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1298 | warning_at (loc, OPT_Waddress, |
1299 | "left operand of comma operator " | |
1300 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1301 | break; |
1302 | case ICV_STATEMENT: | |
61f69bc9 | 1303 | warning_at (loc, OPT_Waddress, |
1304 | "statement is a reference, not call, to function %qE", | |
1305 | expr); | |
dab3247a | 1306 | break; |
1307 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1308 | warning_at (loc, OPT_Waddress, |
1309 | "for increment expression " | |
1310 | "is a reference, not call, to function %qE", expr); | |
dab3247a | 1311 | break; |
1312 | default: | |
1313 | gcc_unreachable (); | |
1314 | } | |
1315 | ||
2056769e | 1316 | if (TREE_CODE (expr) == COMPONENT_REF) |
1317 | expr = TREE_OPERAND (expr, 0); | |
1318 | } | |
b1a8d4ce | 1319 | } |
9031d10b | 1320 | |
e3cfe3ce | 1321 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 1322 | { |
dab3247a | 1323 | if (implicit != ICV_CAST |
5e2a4133 | 1324 | && warn_unused_value |
1325 | && !TREE_NO_WARNING (expr) | |
1326 | && !processing_template_decl) | |
1fe46df1 | 1327 | { |
1328 | /* The middle end does not warn about expressions that have | |
1329 | been explicitly cast to void, so we must do so here. */ | |
ebd21de4 | 1330 | if (!TREE_SIDE_EFFECTS (expr)) { |
1331 | if (complain & tf_warning) | |
dab3247a | 1332 | switch (implicit) |
1333 | { | |
1334 | case ICV_SECOND_OF_COND: | |
61f69bc9 | 1335 | warning_at (loc, OPT_Wunused_value, |
1336 | "second operand of conditional expression " | |
1337 | "has no effect"); | |
dab3247a | 1338 | break; |
1339 | case ICV_THIRD_OF_COND: | |
61f69bc9 | 1340 | warning_at (loc, OPT_Wunused_value, |
1341 | "third operand of conditional expression " | |
1342 | "has no effect"); | |
dab3247a | 1343 | break; |
1344 | case ICV_RIGHT_OF_COMMA: | |
61f69bc9 | 1345 | warning_at (loc, OPT_Wunused_value, |
1346 | "right operand of comma operator has no effect"); | |
dab3247a | 1347 | break; |
1348 | case ICV_LEFT_OF_COMMA: | |
61f69bc9 | 1349 | warning_at (loc, OPT_Wunused_value, |
1350 | "left operand of comma operator has no effect"); | |
dab3247a | 1351 | break; |
1352 | case ICV_STATEMENT: | |
61f69bc9 | 1353 | warning_at (loc, OPT_Wunused_value, |
1354 | "statement has no effect"); | |
dab3247a | 1355 | break; |
1356 | case ICV_THIRD_IN_FOR: | |
61f69bc9 | 1357 | warning_at (loc, OPT_Wunused_value, |
1358 | "for increment expression has no effect"); | |
dab3247a | 1359 | break; |
1360 | default: | |
1361 | gcc_unreachable (); | |
1362 | } | |
ebd21de4 | 1363 | } |
9031d10b | 1364 | else |
1365 | { | |
1fe46df1 | 1366 | tree e; |
1367 | enum tree_code code; | |
607a5d68 | 1368 | enum tree_code_class tclass; |
9031d10b | 1369 | |
1fe46df1 | 1370 | e = expr; |
1371 | /* We might like to warn about (say) "(int) f()", as the | |
1372 | cast has no effect, but the compiler itself will | |
1373 | generate implicit conversions under some | |
324d8f2d | 1374 | circumstances. (For example a block copy will be |
1fe46df1 | 1375 | turned into a call to "__builtin_memcpy", with a |
1376 | conversion of the return value to an appropriate | |
1377 | type.) So, to avoid false positives, we strip | |
416ce344 | 1378 | conversions. Do not use STRIP_NOPs because it will |
1379 | not strip conversions to "void", as that is not a | |
1380 | mode-preserving conversion. */ | |
1381 | while (TREE_CODE (e) == NOP_EXPR) | |
1382 | e = TREE_OPERAND (e, 0); | |
1fe46df1 | 1383 | |
1384 | code = TREE_CODE (e); | |
607a5d68 | 1385 | tclass = TREE_CODE_CLASS (code); |
1386 | if ((tclass == tcc_comparison | |
1387 | || tclass == tcc_unary | |
1388 | || (tclass == tcc_binary | |
1fe46df1 | 1389 | && !(code == MODIFY_EXPR |
1390 | || code == INIT_EXPR | |
1391 | || code == PREDECREMENT_EXPR | |
1392 | || code == PREINCREMENT_EXPR | |
1393 | || code == POSTDECREMENT_EXPR | |
1394 | || code == POSTINCREMENT_EXPR))) | |
ebd21de4 | 1395 | && (complain & tf_warning)) |
61f69bc9 | 1396 | warning_at (loc, OPT_Wunused_value, "value computed is not used"); |
1fe46df1 | 1397 | } |
1398 | } | |
00fa9079 | 1399 | expr = build1 (CONVERT_EXPR, void_type_node, expr); |
b1a8d4ce | 1400 | } |
de5ad4cb | 1401 | if (! TREE_SIDE_EFFECTS (expr)) |
1402 | expr = void_zero_node; | |
b1a8d4ce | 1403 | return expr; |
1404 | } | |
1405 | ||
d81e00a4 | 1406 | /* Create an expression whose value is that of EXPR, |
1407 | converted to type TYPE. The TREE_TYPE of the value | |
1408 | is always TYPE. This function implements all reasonable | |
1409 | conversions; callers should filter out those that are | |
c4a8ac95 | 1410 | not permitted by the language being compiled. |
1411 | ||
1412 | Most of this routine is from build_reinterpret_cast. | |
1413 | ||
a17c2a3a | 1414 | The back end cannot call cp_convert (what was convert) because |
c4a8ac95 | 1415 | conversions to/from basetypes may involve memory references |
1416 | (vbases) and adding or subtracting small values (multiple | |
1417 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 1418 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 1419 | |
1420 | Also, if we ever support range variables, we'll probably also have to | |
1421 | do a little bit more work. */ | |
d81e00a4 | 1422 | |
1423 | tree | |
35771a9a | 1424 | convert (tree type, tree expr) |
d81e00a4 | 1425 | { |
c4a8ac95 | 1426 | tree intype; |
1427 | ||
1428 | if (type == error_mark_node || expr == error_mark_node) | |
1429 | return error_mark_node; | |
1430 | ||
c4a8ac95 | 1431 | intype = TREE_TYPE (expr); |
1432 | ||
6686e84d | 1433 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
13f0eb20 | 1434 | return fold_if_not_in_template (build_nop (type, expr)); |
c4a8ac95 | 1435 | |
1436 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
c4698a21 | 1437 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION, |
1438 | tf_warning_or_error); | |
d81e00a4 | 1439 | } |
1440 | ||
c4a8ac95 | 1441 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 1442 | are not normally allowed due to access restrictions |
1443 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 1444 | |
471086d6 | 1445 | tree |
c4698a21 | 1446 | convert_force (tree type, tree expr, int convtype, tsubst_flags_t complain) |
471086d6 | 1447 | { |
cd16867a | 1448 | tree e = expr; |
1449 | enum tree_code code = TREE_CODE (type); | |
471086d6 | 1450 | |
1451 | if (code == REFERENCE_TYPE) | |
9031d10b | 1452 | return (fold_if_not_in_template |
c4698a21 | 1453 | (convert_to_reference (type, e, CONV_C_CAST, 0, |
1454 | NULL_TREE, complain))); | |
471086d6 | 1455 | |
1456 | if (code == POINTER_TYPE) | |
c4698a21 | 1457 | return fold_if_not_in_template (convert_to_pointer_force (type, e, |
1458 | complain)); | |
471086d6 | 1459 | |
ac9386a0 | 1460 | /* From typeck.c convert_for_assignment */ |
471086d6 | 1461 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
1462 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
1463 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 1464 | || integer_zerop (e) |
1465 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1466 | && TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 1467 | /* compatible pointer to member functions. */ |
1468 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1, | |
c4698a21 | 1469 | /*c_cast_p=*/1, complain); |
a74e8896 | 1470 | |
c4698a21 | 1471 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL, complain); |
471086d6 | 1472 | } |
1473 | ||
471086d6 | 1474 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1475 | exists, return the attempted conversion. This may | |
1476 | return ERROR_MARK_NODE if the conversion is not | |
1477 | allowed (references private members, etc). | |
1478 | If no conversion exists, NULL_TREE is returned. | |
1479 | ||
ce28ee2e | 1480 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit |
1481 | object parameter, or by the second standard conversion sequence if | |
1482 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1483 | (jason 8/9/95) */ | |
471086d6 | 1484 | |
ef9571e5 | 1485 | static tree |
8999978b | 1486 | build_type_conversion (tree xtype, tree expr) |
471086d6 | 1487 | { |
1488 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1489 | into the required type. */ |
66bbeb85 | 1490 | return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL, |
1491 | tf_warning_or_error); | |
471086d6 | 1492 | } |
1493 | ||
1e66592c | 1494 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1495 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
35771a9a | 1496 | which indicates which types are suitable. If COMPLAIN is true, complain |
1e66592c | 1497 | about ambiguity; otherwise, the caller will deal with it. */ |
471086d6 | 1498 | |
1e66592c | 1499 | tree |
35771a9a | 1500 | build_expr_type_conversion (int desires, tree expr, bool complain) |
471086d6 | 1501 | { |
1e66592c | 1502 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1503 | tree conv = NULL_TREE; |
bdd152ce | 1504 | tree winner = NULL_TREE; |
471086d6 | 1505 | |
9031d10b | 1506 | if (expr == null_node |
1507 | && (desires & WANT_INT) | |
954885ed | 1508 | && !(desires & WANT_NULL)) |
db30b351 | 1509 | { |
1510 | source_location loc = | |
1511 | expansion_point_location_if_in_system_header (input_location); | |
1512 | ||
1513 | warning_at (loc, OPT_Wconversion_null, | |
1514 | "converting NULL to non-pointer type"); | |
1515 | } | |
9031d10b | 1516 | |
3d411d73 | 1517 | if (basetype == error_mark_node) |
1518 | return error_mark_node; | |
1519 | ||
95397ff9 | 1520 | if (! MAYBE_CLASS_TYPE_P (basetype)) |
bdd152ce | 1521 | switch (TREE_CODE (basetype)) |
1522 | { | |
1523 | case INTEGER_TYPE: | |
954885ed | 1524 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1525 | return expr; |
1526 | /* else fall through... */ | |
1527 | ||
1528 | case BOOLEAN_TYPE: | |
1529 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1530 | case ENUMERAL_TYPE: | |
1531 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1532 | case REAL_TYPE: | |
1533 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1534 | case POINTER_TYPE: | |
1535 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
9031d10b | 1536 | |
bdd152ce | 1537 | case FUNCTION_TYPE: |
1538 | case ARRAY_TYPE: | |
4405c1ad | 1539 | return (desires & WANT_POINTER) ? decay_conversion (expr, |
1540 | tf_warning_or_error) | |
653e5405 | 1541 | : NULL_TREE; |
96ec9e30 | 1542 | |
64ec1ad6 | 1543 | case COMPLEX_TYPE: |
96ec9e30 | 1544 | case VECTOR_TYPE: |
64ec1ad6 | 1545 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1546 | return NULL_TREE; |
1547 | switch (TREE_CODE (TREE_TYPE (basetype))) | |
1548 | { | |
1549 | case INTEGER_TYPE: | |
1550 | case BOOLEAN_TYPE: | |
1551 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1552 | case ENUMERAL_TYPE: | |
1553 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1554 | case REAL_TYPE: | |
1555 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1556 | default: | |
1557 | return NULL_TREE; | |
1558 | } | |
1559 | ||
bdd152ce | 1560 | default: |
1561 | return NULL_TREE; | |
1562 | } | |
1563 | ||
1564 | /* The code for conversions from class type is currently only used for | |
1565 | delete expressions. Other expressions are handled by build_new_op. */ | |
a5f2d620 | 1566 | if (!complete_type_or_maybe_complain (basetype, expr, complain)) |
f8182e08 | 1567 | return error_mark_node; |
1568 | if (!TYPE_HAS_CONVERSION (basetype)) | |
bdd152ce | 1569 | return NULL_TREE; |
1570 | ||
9960d752 | 1571 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) |
bdd152ce | 1572 | { |
1573 | int win = 0; | |
1574 | tree candidate; | |
1575 | tree cand = TREE_VALUE (conv); | |
c1ca2f12 | 1576 | cand = OVL_CURRENT (cand); |
bdd152ce | 1577 | |
1578 | if (winner && winner == cand) | |
1579 | continue; | |
1580 | ||
cf7aa2e5 | 1581 | if (DECL_NONCONVERTING_P (cand)) |
1582 | continue; | |
1583 | ||
da7eaa22 | 1584 | if (TREE_CODE (cand) == TEMPLATE_DECL) |
1585 | { | |
1586 | if (complain) | |
1587 | { | |
1588 | error ("ambiguous default type conversion from %qT", | |
1589 | basetype); | |
1590 | error (" candidate conversions include %qD", cand); | |
1591 | } | |
1592 | return error_mark_node; | |
1593 | } | |
1594 | ||
ef4534a3 | 1595 | candidate = non_reference (TREE_TYPE (TREE_TYPE (cand))); |
bdd152ce | 1596 | |
1597 | switch (TREE_CODE (candidate)) | |
1598 | { | |
1599 | case BOOLEAN_TYPE: | |
1600 | case INTEGER_TYPE: | |
1601 | win = (desires & WANT_INT); break; | |
1602 | case ENUMERAL_TYPE: | |
1603 | win = (desires & WANT_ENUM); break; | |
1604 | case REAL_TYPE: | |
1605 | win = (desires & WANT_FLOAT); break; | |
1606 | case POINTER_TYPE: | |
1607 | win = (desires & WANT_POINTER); break; | |
1608 | ||
64ec1ad6 | 1609 | case COMPLEX_TYPE: |
96ec9e30 | 1610 | case VECTOR_TYPE: |
64ec1ad6 | 1611 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1612 | break; |
1613 | switch (TREE_CODE (TREE_TYPE (candidate))) | |
1614 | { | |
1615 | case BOOLEAN_TYPE: | |
1616 | case INTEGER_TYPE: | |
1617 | win = (desires & WANT_INT); break; | |
1618 | case ENUMERAL_TYPE: | |
1619 | win = (desires & WANT_ENUM); break; | |
1620 | case REAL_TYPE: | |
1621 | win = (desires & WANT_FLOAT); break; | |
1622 | default: | |
1623 | break; | |
1624 | } | |
1625 | break; | |
1626 | ||
bdd152ce | 1627 | default: |
1628 | break; | |
1629 | } | |
1630 | ||
1631 | if (win) | |
1632 | { | |
1633 | if (winner) | |
1634 | { | |
1635 | if (complain) | |
1636 | { | |
0a25aad6 | 1637 | error ("ambiguous default type conversion from %qT", |
653e5405 | 1638 | basetype); |
0a25aad6 | 1639 | error (" candidate conversions include %qD and %qD", |
653e5405 | 1640 | winner, cand); |
bdd152ce | 1641 | } |
1642 | return error_mark_node; | |
1643 | } | |
1644 | else | |
1645 | winner = cand; | |
1646 | } | |
1647 | } | |
1e66592c | 1648 | |
bdd152ce | 1649 | if (winner) |
1650 | { | |
ef4534a3 | 1651 | tree type = non_reference (TREE_TYPE (TREE_TYPE (winner))); |
66bbeb85 | 1652 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL, |
1653 | tf_warning_or_error); | |
471086d6 | 1654 | } |
1e66592c | 1655 | |
985e9ee0 | 1656 | return NULL_TREE; |
471086d6 | 1657 | } |
bc3887cf | 1658 | |
96624a9e | 1659 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1660 | ||
bc3887cf | 1661 | tree |
35771a9a | 1662 | type_promotes_to (tree type) |
bc3887cf | 1663 | { |
2b3c93a3 | 1664 | tree promoted_type; |
1665 | ||
ce28ee2e | 1666 | if (type == error_mark_node) |
1667 | return error_mark_node; | |
1668 | ||
bc3887cf | 1669 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1670 | |
2b3c93a3 | 1671 | /* Check for promotions of target-defined types first. */ |
1672 | promoted_type = targetm.promoted_type (type); | |
1673 | if (promoted_type) | |
1674 | return promoted_type; | |
1675 | ||
bb0726a1 | 1676 | /* bool always promotes to int (not unsigned), even if it's the same |
1677 | size. */ | |
9e1a8234 | 1678 | if (TREE_CODE (type) == BOOLEAN_TYPE) |
bb0726a1 | 1679 | type = integer_type_node; |
1680 | ||
9fd75d52 | 1681 | /* Scoped enums don't promote, but pretend they do for backward ABI bug |
1682 | compatibility wrt varargs. */ | |
72fc0f64 | 1683 | else if (SCOPED_ENUM_P (type) && abi_version_at_least (6)) |
1684 | ; | |
1685 | ||
bb0726a1 | 1686 | /* Normally convert enums to int, but convert wide enums to something |
1687 | wider. */ | |
1688 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
924bbf02 | 1689 | || type == char16_type_node |
1690 | || type == char32_type_node | |
bb0726a1 | 1691 | || type == wchar_type_node) |
6c9497b1 | 1692 | { |
1693 | int precision = MAX (TYPE_PRECISION (type), | |
1694 | TYPE_PRECISION (integer_type_node)); | |
771d21fa | 1695 | tree totype = c_common_type_for_size (precision, 0); |
72fc0f64 | 1696 | if (SCOPED_ENUM_P (type)) |
1697 | warning (OPT_Wabi, "scoped enum %qT will not promote to an integral " | |
1698 | "type in a future version of GCC", type); | |
bb9c1a09 | 1699 | if (TREE_CODE (type) == ENUMERAL_TYPE) |
1700 | type = ENUM_UNDERLYING_TYPE (type); | |
78a8ed03 | 1701 | if (TYPE_UNSIGNED (type) |
6c9497b1 | 1702 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) |
771d21fa | 1703 | type = c_common_type_for_size (precision, 1); |
6c9497b1 | 1704 | else |
1705 | type = totype; | |
1706 | } | |
d7aeef06 | 1707 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1708 | { |
d0acef9e | 1709 | /* Retain unsignedness if really not getting bigger. */ |
78a8ed03 | 1710 | if (TYPE_UNSIGNED (type) |
d0acef9e | 1711 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1712 | type = unsigned_type_node; |
1713 | else | |
1714 | type = integer_type_node; | |
1715 | } | |
1716 | else if (type == float_type_node) | |
1717 | type = double_type_node; | |
9031d10b | 1718 | |
a681799d | 1719 | return type; |
bc3887cf | 1720 | } |
668ae905 | 1721 | |
668ae905 | 1722 | /* The routines below this point are carefully written to conform to |
1723 | the standard. They use the same terminology, and follow the rules | |
1724 | closely. Although they are used only in pt.c at the moment, they | |
1725 | should presumably be used everywhere in the future. */ | |
1726 | ||
1146f179 | 1727 | /* Attempt to perform qualification conversions on EXPR to convert it |
1728 | to TYPE. Return the resulting expression, or error_mark_node if | |
1729 | the conversion was impossible. */ | |
1730 | ||
9031d10b | 1731 | tree |
35771a9a | 1732 | perform_qualification_conversions (tree type, tree expr) |
668ae905 | 1733 | { |
1bc16cab | 1734 | tree expr_type; |
1735 | ||
1736 | expr_type = TREE_TYPE (expr); | |
1737 | ||
3b087710 | 1738 | if (same_type_p (type, expr_type)) |
1739 | return expr; | |
1740 | else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type) | |
1741 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type))) | |
1bc16cab | 1742 | return build_nop (type, expr); |
05765a91 | 1743 | else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (expr_type) |
1bc16cab | 1744 | && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type), |
1745 | TYPE_PTRMEM_CLASS_TYPE (expr_type)) | |
1746 | && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type), | |
1747 | TYPE_PTRMEM_POINTED_TO_TYPE (expr_type))) | |
1748 | return build_nop (type, expr); | |
1146f179 | 1749 | else |
1750 | return error_mark_node; | |
668ae905 | 1751 | } |