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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, |
f352a3fb | 3 | 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 |
aa139c3f | 4 | 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" |
f0eaeecd | 38 | #include "toplev.h" |
2e8226f7 | 39 | #include "decl.h" |
7a979707 | 40 | #include "target.h" |
96624a9e | 41 | |
e5ead12a | 42 | static tree cp_convert_to_pointer (tree, tree); |
35771a9a | 43 | static tree convert_to_pointer_force (tree, tree); |
ef9571e5 | 44 | static tree build_type_conversion (tree, tree); |
35771a9a | 45 | static tree build_up_reference (tree, tree, int, tree); |
46 | static void warn_ref_binding (tree, tree, tree); | |
71ccdfff | 47 | |
471086d6 | 48 | /* Change of width--truncation and extension of integers or reals-- |
49 | is represented with NOP_EXPR. Proper functioning of many things | |
50 | assumes that no other conversions can be NOP_EXPRs. | |
51 | ||
52 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
53 | Converting integer to real uses FLOAT_EXPR | |
54 | and real to integer uses FIX_TRUNC_EXPR. | |
55 | ||
56 | Here is a list of all the functions that assume that widening and | |
57 | narrowing is always done with a NOP_EXPR: | |
58 | In convert.c, convert_to_integer. | |
59 | In c-typeck.c, build_binary_op_nodefault (boolean ops), | |
653e5405 | 60 | and c_common_truthvalue_conversion. |
471086d6 | 61 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
62 | In fold-const.c: fold. | |
63 | In tree.c: get_narrower and get_unwidened. | |
64 | ||
65 | C++: in multiple-inheritance, converting between pointers may involve | |
66 | adjusting them by a delta stored within the class definition. */ | |
67 | \f | |
68 | /* Subroutines of `convert'. */ | |
69 | ||
471086d6 | 70 | /* if converting pointer to pointer |
71 | if dealing with classes, check for derived->base or vice versa | |
72 | else if dealing with method pointers, delegate | |
73 | else convert blindly | |
74 | else if converting class, pass off to build_type_conversion | |
e5ead12a | 75 | else try C-style pointer conversion. */ |
96624a9e | 76 | |
471086d6 | 77 | static tree |
e5ead12a | 78 | cp_convert_to_pointer (tree type, tree expr) |
471086d6 | 79 | { |
cd16867a | 80 | tree intype = TREE_TYPE (expr); |
81 | enum tree_code form; | |
f82eeb87 | 82 | tree rval; |
8bf328bf | 83 | if (intype == error_mark_node) |
84 | return error_mark_node; | |
74002e1d | 85 | |
95397ff9 | 86 | if (MAYBE_CLASS_TYPE_P (intype)) |
96624a9e | 87 | { |
96624a9e | 88 | intype = complete_type (intype); |
4b72716d | 89 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 90 | { |
0a25aad6 | 91 | error ("can't convert from incomplete type %qT to %qT", |
653e5405 | 92 | intype, type); |
96624a9e | 93 | return error_mark_node; |
94 | } | |
95 | ||
8999978b | 96 | rval = build_type_conversion (type, expr); |
96624a9e | 97 | if (rval) |
98 | { | |
99 | if (rval == error_mark_node) | |
0a25aad6 | 100 | error ("conversion of %qE from %qT to %qT is ambiguous", |
653e5405 | 101 | expr, intype, type); |
96624a9e | 102 | return rval; |
103 | } | |
104 | } | |
105 | ||
860740a7 | 106 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 107 | if (TREE_CODE (type) == POINTER_TYPE |
108 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
e3cfe3ce | 109 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 110 | { |
6ab399e8 | 111 | if (TYPE_PTRMEMFUNC_P (intype) |
112 | || TREE_CODE (intype) == METHOD_TYPE) | |
113 | return convert_member_func_to_ptr (type, expr); | |
a63bc44c | 114 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) |
115 | return build_nop (type, expr); | |
38281c46 | 116 | intype = TREE_TYPE (expr); |
117 | } | |
118 | ||
311e42bc | 119 | if (expr == error_mark_node) |
120 | return error_mark_node; | |
121 | ||
74002e1d | 122 | form = TREE_CODE (intype); |
123 | ||
2b77484d | 124 | if (POINTER_TYPE_P (intype)) |
471086d6 | 125 | { |
126 | intype = TYPE_MAIN_VARIANT (intype); | |
127 | ||
128 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 129 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 130 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
95397ff9 | 131 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
132 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
4a2680fc | 133 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
471086d6 | 134 | { |
135 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 136 | tree binfo; |
8999978b | 137 | tree intype_class; |
138 | tree type_class; | |
139 | bool same_p; | |
4a2680fc | 140 | |
8999978b | 141 | intype_class = TREE_TYPE (intype); |
142 | type_class = TREE_TYPE (type); | |
143 | ||
9031d10b | 144 | same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class), |
8999978b | 145 | TYPE_MAIN_VARIANT (type_class)); |
146 | binfo = NULL_TREE; | |
c0af329c | 147 | /* Try derived to base conversion. */ |
8999978b | 148 | if (!same_p) |
149 | binfo = lookup_base (intype_class, type_class, ba_check, NULL); | |
150 | if (!same_p && !binfo) | |
471086d6 | 151 | { |
c0af329c | 152 | /* Try base to derived conversion. */ |
8999978b | 153 | binfo = lookup_base (type_class, intype_class, ba_check, NULL); |
471086d6 | 154 | code = MINUS_EXPR; |
155 | } | |
4a2680fc | 156 | if (binfo == error_mark_node) |
157 | return error_mark_node; | |
8999978b | 158 | if (binfo || same_p) |
471086d6 | 159 | { |
8999978b | 160 | if (binfo) |
161 | expr = build_base_path (code, expr, binfo, 0); | |
c0af329c | 162 | /* Add any qualifier conversions. */ |
8999978b | 163 | return build_nop (type, expr); |
471086d6 | 164 | } |
165 | } | |
471086d6 | 166 | |
1bc16cab | 167 | if (TYPE_PTRMEMFUNC_P (type)) |
bea7d742 | 168 | { |
0a25aad6 | 169 | error ("cannot convert %qE from type %qT to type %qT", |
653e5405 | 170 | expr, intype, type); |
1bc16cab | 171 | return error_mark_node; |
172 | } | |
a17aefa2 | 173 | |
1bc16cab | 174 | return build_nop (type, expr); |
175 | } | |
e5ead12a | 176 | else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) |
177 | || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) | |
178 | return convert_ptrmem (type, expr, /*allow_inverse_p=*/false, | |
179 | /*c_cast_p=*/false); | |
2b77484d | 180 | else if (TYPE_PTRMEMFUNC_P (intype)) |
181 | { | |
a63bc44c | 182 | if (!warn_pmf2ptr) |
183 | { | |
184 | if (TREE_CODE (expr) == PTRMEM_CST) | |
185 | return cp_convert_to_pointer (type, | |
e5ead12a | 186 | PTRMEM_CST_MEMBER (expr)); |
a63bc44c | 187 | else if (TREE_CODE (expr) == OFFSET_REF) |
188 | { | |
189 | tree object = TREE_OPERAND (expr, 0); | |
190 | return get_member_function_from_ptrfunc (&object, | |
191 | TREE_OPERAND (expr, 1)); | |
192 | } | |
193 | } | |
0a25aad6 | 194 | error ("cannot convert %qE from type %qT to type %qT", |
653e5405 | 195 | expr, intype, type); |
2b77484d | 196 | return error_mark_node; |
197 | } | |
471086d6 | 198 | |
471086d6 | 199 | if (integer_zerop (expr)) |
200 | { | |
2b77484d | 201 | if (TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 202 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
203 | /*c_cast_p=*/false); | |
ad63a0fc | 204 | |
606b494c | 205 | if (TYPE_PTRMEM_P (type)) |
7c446c95 | 206 | { |
207 | /* A NULL pointer-to-member is represented by -1, not by | |
208 | zero. */ | |
697bbc3f | 209 | expr = build_int_cst_type (type, -1); |
7c446c95 | 210 | } |
ad63a0fc | 211 | else |
7016c612 | 212 | expr = build_int_cst (type, 0); |
9031d10b | 213 | |
471086d6 | 214 | return expr; |
215 | } | |
1bc16cab | 216 | else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form)) |
de1f960a | 217 | { |
0a25aad6 | 218 | error ("invalid conversion from %qT to %qT", intype, type); |
de1f960a | 219 | return error_mark_node; |
220 | } | |
471086d6 | 221 | |
bb0726a1 | 222 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 223 | { |
c5aa1e92 | 224 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 225 | return build1 (CONVERT_EXPR, type, expr); |
771d21fa | 226 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr); |
092b1d6f | 227 | /* Modes may be different but sizes should be the same. There |
228 | is supposed to be some integral type that is the same width | |
229 | as a pointer. */ | |
230 | gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
231 | == GET_MODE_SIZE (TYPE_MODE (type))); | |
9031d10b | 232 | |
471086d6 | 233 | return convert_to_pointer (type, expr); |
234 | } | |
235 | ||
cc4d0855 | 236 | if (type_unknown_p (expr)) |
0fbca5e8 | 237 | return instantiate_type (type, expr, tf_warning_or_error); |
cc4d0855 | 238 | |
0a25aad6 | 239 | error ("cannot convert %qE from type %qT to type %qT", |
653e5405 | 240 | expr, intype, type); |
471086d6 | 241 | return error_mark_node; |
242 | } | |
243 | ||
244 | /* Like convert, except permit conversions to take place which | |
245 | are not normally allowed due to access restrictions | |
246 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 247 | |
471086d6 | 248 | static tree |
35771a9a | 249 | convert_to_pointer_force (tree type, tree expr) |
471086d6 | 250 | { |
cd16867a | 251 | tree intype = TREE_TYPE (expr); |
252 | enum tree_code form = TREE_CODE (intype); | |
9031d10b | 253 | |
471086d6 | 254 | if (form == POINTER_TYPE) |
255 | { | |
256 | intype = TYPE_MAIN_VARIANT (intype); | |
257 | ||
258 | if (TYPE_MAIN_VARIANT (type) != intype | |
259 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
95397ff9 | 260 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (type)) |
261 | && MAYBE_CLASS_TYPE_P (TREE_TYPE (intype)) | |
471086d6 | 262 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
263 | { | |
264 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 265 | tree binfo; |
266 | ||
267 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
ada40935 | 268 | ba_unique, NULL); |
4a2680fc | 269 | if (!binfo) |
471086d6 | 270 | { |
4a2680fc | 271 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
ada40935 | 272 | ba_unique, NULL); |
4a2680fc | 273 | code = MINUS_EXPR; |
471086d6 | 274 | } |
4a2680fc | 275 | if (binfo == error_mark_node) |
276 | return error_mark_node; | |
277 | if (binfo) | |
471086d6 | 278 | { |
4a2680fc | 279 | expr = build_base_path (code, expr, binfo, 0); |
653e5405 | 280 | if (expr == error_mark_node) |
281 | return error_mark_node; | |
c0af329c | 282 | /* Add any qualifier conversions. */ |
4a2680fc | 283 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
284 | TREE_TYPE (type))) | |
8999978b | 285 | expr = build_nop (type, expr); |
4a2680fc | 286 | return expr; |
471086d6 | 287 | } |
471086d6 | 288 | } |
471086d6 | 289 | } |
290 | ||
e5ead12a | 291 | return cp_convert_to_pointer (type, expr); |
471086d6 | 292 | } |
293 | ||
294 | /* We are passing something to a function which requires a reference. | |
295 | The type we are interested in is in TYPE. The initial | |
296 | value we have to begin with is in ARG. | |
297 | ||
298 | FLAGS controls how we manage access checking. | |
ca106ab1 | 299 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
300 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 301 | |
471086d6 | 302 | static tree |
35771a9a | 303 | build_up_reference (tree type, tree arg, int flags, tree decl) |
471086d6 | 304 | { |
c76251c1 | 305 | tree rval; |
0543e7a9 | 306 | tree argtype = TREE_TYPE (arg); |
471086d6 | 307 | tree target_type = TREE_TYPE (type); |
471086d6 | 308 | |
b4df430b | 309 | gcc_assert (TREE_CODE (type) == REFERENCE_TYPE); |
471086d6 | 310 | |
c76251c1 | 311 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 312 | { |
ca106ab1 | 313 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
314 | here because it needs to live as long as DECL. */ | |
c76251c1 | 315 | tree targ = arg; |
ca106ab1 | 316 | |
7c09476d | 317 | arg = make_temporary_var_for_ref_to_temp (decl, TREE_TYPE (arg)); |
c23ebfdd | 318 | |
319 | /* Process the initializer for the declaration. */ | |
38281c46 | 320 | DECL_INITIAL (arg) = targ; |
d91303a6 | 321 | cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE, |
011310f7 | 322 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 323 | } |
c76251c1 | 324 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
1d8e4310 | 325 | return get_target_expr (arg); |
1ad432f2 | 326 | |
ca106ab1 | 327 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 328 | address, transform all occurrences of the register, into a memory |
329 | reference we could win better. */ | |
ebd21de4 | 330 | rval = cp_build_unary_op (ADDR_EXPR, arg, 1, tf_warning_or_error); |
15e55420 | 331 | if (rval == error_mark_node) |
332 | return error_mark_node; | |
333 | ||
6686e84d | 334 | if ((flags & LOOKUP_PROTECT) |
335 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
95397ff9 | 336 | && MAYBE_CLASS_TYPE_P (argtype) |
337 | && MAYBE_CLASS_TYPE_P (target_type)) | |
6686e84d | 338 | { |
7e6960e0 | 339 | /* We go through lookup_base for the access control. */ |
4a2680fc | 340 | tree binfo = lookup_base (argtype, target_type, ba_check, NULL); |
6686e84d | 341 | if (binfo == error_mark_node) |
342 | return error_mark_node; | |
343 | if (binfo == NULL_TREE) | |
344 | return error_not_base_type (target_type, argtype); | |
4a2680fc | 345 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1); |
6686e84d | 346 | } |
c76251c1 | 347 | else |
348 | rval | |
349 | = convert_to_pointer_force (build_pointer_type (target_type), rval); | |
8999978b | 350 | return build_nop (type, rval); |
471086d6 | 351 | } |
352 | ||
519ba62c | 353 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
354 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
355 | for diagnostics. | |
9031d10b | 356 | |
519ba62c | 357 | [dcl.init.ref] says that if an rvalue is used to |
358 | initialize a reference, then the reference must be to a | |
359 | non-volatile const type. */ | |
360 | ||
361 | static void | |
35771a9a | 362 | warn_ref_binding (tree reftype, tree intype, tree decl) |
519ba62c | 363 | { |
364 | tree ttl = TREE_TYPE (reftype); | |
9031d10b | 365 | |
519ba62c | 366 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) |
367 | { | |
368 | const char *msg; | |
369 | ||
370 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
ca82e026 | 371 | msg = G_("initialization of volatile reference type %q#T from " |
372 | "rvalue of type %qT"); | |
519ba62c | 373 | else if (CP_TYPE_VOLATILE_P (ttl)) |
ca82e026 | 374 | msg = G_("conversion to volatile reference type %q#T " |
375 | "from rvalue of type %qT"); | |
519ba62c | 376 | else if (decl) |
ca82e026 | 377 | msg = G_("initialization of non-const reference type %q#T from " |
378 | "rvalue of type %qT"); | |
519ba62c | 379 | else |
ca82e026 | 380 | msg = G_("conversion to non-const reference type %q#T from " |
381 | "rvalue of type %qT"); | |
519ba62c | 382 | |
2b9e3597 | 383 | permerror (input_location, msg, reftype, intype); |
519ba62c | 384 | } |
385 | } | |
386 | ||
471086d6 | 387 | /* For C++: Only need to do one-level references, but cannot |
388 | get tripped up on signed/unsigned differences. | |
389 | ||
d81e00a4 | 390 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
391 | initialized. It can be error_mark_node if we don't know the _DECL but | |
392 | we know it's an initialization. */ | |
471086d6 | 393 | |
471086d6 | 394 | tree |
35771a9a | 395 | convert_to_reference (tree reftype, tree expr, int convtype, |
653e5405 | 396 | int flags, tree decl) |
471086d6 | 397 | { |
cd16867a | 398 | tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); |
399 | tree intype; | |
471086d6 | 400 | tree rval = NULL_TREE; |
1a3f833b | 401 | tree rval_as_conversion = NULL_TREE; |
1bc16cab | 402 | bool can_convert_intype_to_type; |
1a3f833b | 403 | |
9031d10b | 404 | if (TREE_CODE (type) == FUNCTION_TYPE |
d32df6a6 | 405 | && TREE_TYPE (expr) == unknown_type_node) |
9031d10b | 406 | expr = instantiate_type (type, expr, |
0a3b29ad | 407 | (flags & LOOKUP_COMPLAIN) |
0fbca5e8 | 408 | ? tf_warning_or_error : tf_none); |
0a3b29ad | 409 | |
410 | if (expr == error_mark_node) | |
411 | return error_mark_node; | |
412 | ||
413 | intype = TREE_TYPE (expr); | |
cc4d0855 | 414 | |
b4df430b | 415 | gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE); |
ab12ed55 | 416 | gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE); |
471086d6 | 417 | |
471086d6 | 418 | intype = TYPE_MAIN_VARIANT (intype); |
419 | ||
1bc16cab | 420 | can_convert_intype_to_type = can_convert (type, intype); |
421 | if (!can_convert_intype_to_type | |
95397ff9 | 422 | && (convtype & CONV_IMPLICIT) && MAYBE_CLASS_TYPE_P (intype) |
1a3f833b | 423 | && ! (flags & LOOKUP_NO_CONVERSION)) |
424 | { | |
425 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
426 | ||
0a4be248 | 427 | rval_as_conversion |
8999978b | 428 | = build_type_conversion (reftype, expr); |
1a3f833b | 429 | |
430 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
431 | && real_lvalue_p (rval_as_conversion)) | |
432 | { | |
433 | expr = rval_as_conversion; | |
434 | rval_as_conversion = NULL_TREE; | |
435 | intype = type; | |
1bc16cab | 436 | can_convert_intype_to_type = 1; |
1a3f833b | 437 | } |
438 | } | |
439 | ||
1bc16cab | 440 | if (((convtype & CONV_STATIC) && can_convert (intype, type)) |
441 | || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type)) | |
471086d6 | 442 | { |
471086d6 | 443 | if (flags & LOOKUP_COMPLAIN) |
444 | { | |
bc3887cf | 445 | tree ttl = TREE_TYPE (reftype); |
cb0ba4ec | 446 | tree ttr = lvalue_type (expr); |
471086d6 | 447 | |
519ba62c | 448 | if (! real_lvalue_p (expr)) |
449 | warn_ref_binding (reftype, intype, decl); | |
9031d10b | 450 | |
519ba62c | 451 | if (! (convtype & CONV_CONST) |
3e04bd45 | 452 | && !at_least_as_qualified_p (ttl, ttr)) |
2b9e3597 | 453 | permerror (input_location, "conversion from %qT to %qT discards qualifiers", |
07317e69 | 454 | ttr, reftype); |
0543e7a9 | 455 | } |
456 | ||
ca106ab1 | 457 | return build_up_reference (reftype, expr, flags, decl); |
471086d6 | 458 | } |
c07b1ad1 | 459 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 460 | { |
461 | /* When casting an lvalue to a reference type, just convert into | |
462 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 463 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 464 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 465 | |
3748625f | 466 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
653e5405 | 467 | meant. */ |
1a3f833b | 468 | if (TREE_CODE (intype) == POINTER_TYPE |
a09db423 | 469 | && (comptypes (TREE_TYPE (intype), type, |
470 | COMPARE_BASE | COMPARE_DERIVED))) | |
c3ceba8e | 471 | warning (0, "casting %qT to %qT does not dereference pointer", |
00952d10 | 472 | intype, reftype); |
9031d10b | 473 | |
ebd21de4 | 474 | rval = cp_build_unary_op (ADDR_EXPR, expr, 0, tf_warning_or_error); |
0543e7a9 | 475 | if (rval != error_mark_node) |
985e9ee0 | 476 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
477 | rval, 0); | |
0543e7a9 | 478 | if (rval != error_mark_node) |
b0722fac | 479 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 480 | } |
0a4be248 | 481 | else |
860740a7 | 482 | { |
483 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
ebd21de4 | 484 | "converting", 0, 0, |
485 | tf_warning_or_error); | |
a66fe4cb | 486 | if (rval == NULL_TREE || rval == error_mark_node) |
487 | return rval; | |
519ba62c | 488 | warn_ref_binding (reftype, intype, decl); |
ca106ab1 | 489 | rval = build_up_reference (reftype, rval, flags, decl); |
860740a7 | 490 | } |
471086d6 | 491 | |
492 | if (rval) | |
493 | { | |
96624a9e | 494 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 495 | return rval; |
496 | } | |
497 | ||
b248d3f7 | 498 | if (flags & LOOKUP_COMPLAIN) |
0a25aad6 | 499 | error ("cannot convert type %qT to type %qT", intype, reftype); |
b248d3f7 | 500 | |
471086d6 | 501 | return error_mark_node; |
502 | } | |
503 | ||
504 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 505 | way down to its lowest form. */ |
506 | ||
471086d6 | 507 | tree |
35771a9a | 508 | convert_from_reference (tree val) |
471086d6 | 509 | { |
73bdcca2 | 510 | if (TREE_TYPE (val) |
511 | && TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE) | |
729f89ff | 512 | { |
2fb61329 | 513 | tree t = TREE_TYPE (TREE_TYPE (val)); |
729f89ff | 514 | tree ref = build1 (INDIRECT_REF, t, val); |
9031d10b | 515 | |
729f89ff | 516 | /* We *must* set TREE_READONLY when dereferencing a pointer to const, |
517 | so that we get the proper error message if the result is used | |
518 | to assign to. Also, &* is supposed to be a no-op. */ | |
519 | TREE_READONLY (ref) = CP_TYPE_CONST_P (t); | |
520 | TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); | |
521 | TREE_SIDE_EFFECTS (ref) | |
522 | = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val)); | |
523 | REFERENCE_REF_P (ref) = 1; | |
524 | val = ref; | |
525 | } | |
9031d10b | 526 | |
471086d6 | 527 | return val; |
528 | } | |
e5dab226 | 529 | |
530 | /* Really perform an lvalue-to-rvalue conversion, including copying an | |
531 | argument of class type into a temporary. */ | |
532 | ||
533 | tree | |
534 | force_rvalue (tree expr) | |
535 | { | |
95397ff9 | 536 | if (MAYBE_CLASS_TYPE_P (TREE_TYPE (expr)) && TREE_CODE (expr) != TARGET_EXPR) |
e5dab226 | 537 | expr = ocp_convert (TREE_TYPE (expr), expr, |
538 | CONV_IMPLICIT|CONV_FORCE_TEMP, LOOKUP_NORMAL); | |
539 | else | |
540 | expr = decay_conversion (expr); | |
541 | ||
542 | return expr; | |
543 | } | |
f5220369 | 544 | |
471086d6 | 545 | \f |
f5220369 | 546 | /* Fold away simple conversions, but make sure the result is an rvalue. */ |
547 | ||
548 | tree | |
549 | cp_fold_convert (tree type, tree expr) | |
550 | { | |
551 | return rvalue (fold_convert (type, expr)); | |
552 | } | |
553 | ||
c4a8ac95 | 554 | /* C++ conversions, preference to static cast conversions. */ |
555 | ||
556 | tree | |
35771a9a | 557 | cp_convert (tree type, tree expr) |
c4a8ac95 | 558 | { |
559 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); | |
560 | } | |
561 | ||
59dd8856 | 562 | /* C++ equivalent of convert_and_check but using cp_convert as the |
563 | conversion function. | |
564 | ||
565 | Convert EXPR to TYPE, warning about conversion problems with constants. | |
566 | Invoke this function on every expression that is converted implicitly, | |
567 | i.e. because of language rules and not because of an explicit cast. */ | |
568 | ||
569 | tree | |
570 | cp_convert_and_check (tree type, tree expr) | |
571 | { | |
572 | tree result; | |
573 | ||
574 | if (TREE_TYPE (expr) == type) | |
575 | return expr; | |
576 | ||
577 | result = cp_convert (type, expr); | |
578 | ||
48d94ede | 579 | if (c_inhibit_evaluation_warnings == 0 |
580 | && !TREE_OVERFLOW_P (expr) | |
581 | && result != error_mark_node) | |
59dd8856 | 582 | warnings_for_convert_and_check (type, expr, result); |
583 | ||
584 | return result; | |
585 | } | |
586 | ||
b248d3f7 | 587 | /* Conversion... |
588 | ||
589 | FLAGS indicates how we should behave. */ | |
590 | ||
471086d6 | 591 | tree |
35771a9a | 592 | ocp_convert (tree type, tree expr, int convtype, int flags) |
471086d6 | 593 | { |
cd16867a | 594 | tree e = expr; |
595 | enum tree_code code = TREE_CODE (type); | |
7a979707 | 596 | const char *invalid_conv_diag; |
2b3c93a3 | 597 | tree e1; |
471086d6 | 598 | |
1bc16cab | 599 | if (error_operand_p (e) || type == error_mark_node) |
471086d6 | 600 | return error_mark_node; |
d81e00a4 | 601 | |
5b592939 | 602 | complete_type (type); |
603 | complete_type (TREE_TYPE (expr)); | |
604 | ||
7a979707 | 605 | if ((invalid_conv_diag |
606 | = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
607 | { | |
608 | error (invalid_conv_diag); | |
609 | return error_mark_node; | |
610 | } | |
611 | ||
13f0eb20 | 612 | e = integral_constant_value (e); |
7745052b | 613 | |
95397ff9 | 614 | if (MAYBE_CLASS_TYPE_P (type) && (convtype & CONV_FORCE_TEMP)) |
1a3f833b | 615 | /* We need a new temporary; don't take this shortcut. */; |
930e8175 | 616 | else if (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (e))) |
ca23ec64 | 617 | { |
daf9ff67 | 618 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 619 | /* The call to fold will not always remove the NOP_EXPR as |
620 | might be expected, since if one of the types is a typedef; | |
755edffd | 621 | the comparison in fold is just equality of pointers, not a |
a09db423 | 622 | call to comptypes. We don't call fold in this case because |
f699c174 | 623 | that can result in infinite recursion; fold will call |
624 | convert, which will call ocp_convert, etc. */ | |
625 | return e; | |
372e0e29 | 626 | /* For complex data types, we need to perform componentwise |
653e5405 | 627 | conversion. */ |
372e0e29 | 628 | else if (TREE_CODE (type) == COMPLEX_TYPE) |
653e5405 | 629 | return fold_if_not_in_template (convert_to_complex (type, e)); |
bdb2219e | 630 | else if (TREE_CODE (e) == TARGET_EXPR) |
631 | { | |
632 | /* Don't build a NOP_EXPR of class type. Instead, change the | |
930e8175 | 633 | type of the temporary. */ |
bdb2219e | 634 | TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type; |
635 | return e; | |
636 | } | |
ca23ec64 | 637 | else |
092b1d6f | 638 | { |
639 | /* We shouldn't be treating objects of ADDRESSABLE type as | |
640 | rvalues. */ | |
641 | gcc_assert (!TREE_ADDRESSABLE (type)); | |
5d7ed6c7 | 642 | return fold_if_not_in_template (build_nop (type, e)); |
092b1d6f | 643 | } |
ca23ec64 | 644 | } |
645 | ||
2b3c93a3 | 646 | e1 = targetm.convert_to_type (type, e); |
647 | if (e1) | |
648 | return e1; | |
649 | ||
d81e00a4 | 650 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 651 | { |
ebd21de4 | 652 | e = convert_to_void (e, /*implicit=*/NULL, tf_warning_or_error); |
aeef2be5 | 653 | return e; |
95b2ac55 | 654 | } |
d81e00a4 | 655 | |
bb0726a1 | 656 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 657 | { |
617abf06 | 658 | tree intype = TREE_TYPE (e); |
384590d4 | 659 | |
660 | if (TREE_CODE (type) == ENUMERAL_TYPE) | |
661 | { | |
662 | /* enum = enum, enum = int, enum = float, (enum)pointer are all | |
663 | errors. */ | |
664 | if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype) | |
653e5405 | 665 | || TREE_CODE (intype) == REAL_TYPE) |
b312a686 | 666 | && ! (convtype & CONV_STATIC)) |
384590d4 | 667 | || TREE_CODE (intype) == POINTER_TYPE) |
668 | { | |
669 | if (flags & LOOKUP_COMPLAIN) | |
2b9e3597 | 670 | permerror (input_location, "conversion from %q#T to %q#T", intype, type); |
471086d6 | 671 | |
384590d4 | 672 | if (!flag_permissive) |
673 | return error_mark_node; | |
674 | } | |
675 | ||
676 | /* [expr.static.cast] | |
677 | ||
678 | 8. A value of integral or enumeration type can be explicitly | |
679 | converted to an enumeration type. The value is unchanged if | |
680 | the original value is within the range of the enumeration | |
681 | values. Otherwise, the resulting enumeration value is | |
682 | unspecified. */ | |
683 | if (TREE_CODE (expr) == INTEGER_CST && !int_fits_type_p (expr, type)) | |
684 | warning (OPT_Wconversion, | |
685 | "the result of the conversion is unspecified because " | |
686 | "%qE is outside the range of type %qT", | |
687 | expr, type); | |
471086d6 | 688 | } |
95397ff9 | 689 | if (MAYBE_CLASS_TYPE_P (intype)) |
471086d6 | 690 | { |
691 | tree rval; | |
8999978b | 692 | rval = build_type_conversion (type, e); |
6495357a | 693 | if (rval) |
694 | return rval; | |
b248d3f7 | 695 | if (flags & LOOKUP_COMPLAIN) |
0a25aad6 | 696 | error ("%q#T used where a %qT was expected", intype, type); |
471086d6 | 697 | return error_mark_node; |
698 | } | |
bb0726a1 | 699 | if (code == BOOLEAN_TYPE) |
ce871053 | 700 | return cp_truthvalue_conversion (e); |
701 | ||
5d7ed6c7 | 702 | return fold_if_not_in_template (convert_to_integer (type, e)); |
471086d6 | 703 | } |
1bc16cab | 704 | if (POINTER_TYPE_P (type) || TYPE_PTR_TO_MEMBER_P (type)) |
e5ead12a | 705 | return fold_if_not_in_template (cp_convert_to_pointer (type, e)); |
684b9d79 | 706 | if (code == VECTOR_TYPE) |
c37ff371 | 707 | { |
708 | tree in_vtype = TREE_TYPE (e); | |
95397ff9 | 709 | if (MAYBE_CLASS_TYPE_P (in_vtype)) |
c37ff371 | 710 | { |
711 | tree ret_val; | |
712 | ret_val = build_type_conversion (type, e); | |
653e5405 | 713 | if (ret_val) |
714 | return ret_val; | |
715 | if (flags & LOOKUP_COMPLAIN) | |
716 | error ("%q#T used where a %qT was expected", in_vtype, type); | |
717 | return error_mark_node; | |
c37ff371 | 718 | } |
5d7ed6c7 | 719 | return fold_if_not_in_template (convert_to_vector (type, e)); |
c37ff371 | 720 | } |
c4a8ac95 | 721 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 722 | { |
95397ff9 | 723 | if (MAYBE_CLASS_TYPE_P (TREE_TYPE (e))) |
471086d6 | 724 | { |
725 | tree rval; | |
8999978b | 726 | rval = build_type_conversion (type, e); |
471086d6 | 727 | if (rval) |
728 | return rval; | |
729 | else | |
b248d3f7 | 730 | if (flags & LOOKUP_COMPLAIN) |
0a25aad6 | 731 | error ("%q#T used where a floating point value was expected", |
b248d3f7 | 732 | TREE_TYPE (e)); |
471086d6 | 733 | } |
c4a8ac95 | 734 | if (code == REAL_TYPE) |
5d7ed6c7 | 735 | return fold_if_not_in_template (convert_to_real (type, e)); |
c4a8ac95 | 736 | else if (code == COMPLEX_TYPE) |
5d7ed6c7 | 737 | return fold_if_not_in_template (convert_to_complex (type, e)); |
471086d6 | 738 | } |
739 | ||
740 | /* New C++ semantics: since assignment is now based on | |
741 | memberwise copying, if the rhs type is derived from the | |
742 | lhs type, then we may still do a conversion. */ | |
95397ff9 | 743 | if (RECORD_OR_UNION_CODE_P (code)) |
471086d6 | 744 | { |
745 | tree dtype = TREE_TYPE (e); | |
c25194fd | 746 | tree ctor = NULL_TREE; |
471086d6 | 747 | |
471086d6 | 748 | dtype = TYPE_MAIN_VARIANT (dtype); |
749 | ||
471086d6 | 750 | /* Conversion between aggregate types. New C++ semantics allow |
751 | objects of derived type to be cast to objects of base type. | |
752 | Old semantics only allowed this between pointers. | |
753 | ||
754 | There may be some ambiguity between using a constructor | |
755 | vs. using a type conversion operator when both apply. */ | |
756 | ||
0a4be248 | 757 | ctor = e; |
860740a7 | 758 | |
8c18e707 | 759 | if (abstract_virtuals_error (NULL_TREE, type)) |
760 | return error_mark_node; | |
6cbb4197 | 761 | |
f82f1250 | 762 | if (BRACE_ENCLOSED_INITIALIZER_P (ctor)) |
763 | ctor = perform_implicit_conversion (type, ctor, tf_warning_or_error); | |
764 | else if ((flags & LOOKUP_ONLYCONVERTING) | |
765 | && ! (CLASS_TYPE_P (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 766 | /* For copy-initialization, first we create a temp of the proper type |
767 | with a user-defined conversion sequence, then we direct-initialize | |
768 | the target with the temp (see [dcl.init]). */ | |
769 | ctor = build_user_type_conversion (type, ctor, flags); | |
3eb89cd8 | 770 | else |
f352a3fb | 771 | { |
772 | VEC(tree,gc) *ctor_vec = make_tree_vector_single (ctor); | |
773 | ctor = build_special_member_call (NULL_TREE, | |
774 | complete_ctor_identifier, | |
775 | &ctor_vec, | |
776 | type, flags, | |
777 | tf_warning_or_error); | |
778 | release_tree_vector (ctor_vec); | |
779 | } | |
0a4be248 | 780 | if (ctor) |
781 | return build_cplus_new (type, ctor); | |
471086d6 | 782 | } |
783 | ||
b248d3f7 | 784 | if (flags & LOOKUP_COMPLAIN) |
a7cc1549 | 785 | { |
786 | /* If the conversion failed and expr was an invalid use of pointer to | |
787 | member function, try to report a meaningful error. */ | |
788 | if (invalid_nonstatic_memfn_p (expr, tf_warning_or_error)) | |
789 | /* We displayed the error message. */; | |
790 | else | |
791 | error ("conversion from %qT to non-scalar type %qT requested", | |
792 | TREE_TYPE (expr), type); | |
793 | } | |
471086d6 | 794 | return error_mark_node; |
795 | } | |
796 | ||
b1a8d4ce | 797 | /* When an expression is used in a void context, its value is discarded and |
798 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
799 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
800 | in a void context. The C++ standard does not define what an `access' to an | |
63eff20d | 801 | object is, but there is reason to believe that it is the lvalue to rvalue |
b1a8d4ce | 802 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it |
803 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
804 | indicates that volatile semantics should be the same between C and C++ | |
805 | where ever possible. C leaves it implementation defined as to what | |
806 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
807 | the volatile object `vp' points to, unless that is an incomplete type. For | |
808 | volatile references we do not do this interpretation, because that would | |
809 | make it impossible to ignore the reference return value from functions. We | |
810 | issue warnings in the confusing cases. | |
9031d10b | 811 | |
f8646185 | 812 | IMPLICIT is non-NULL iff an expression is being implicitly converted; it |
813 | is NULL when the user is explicitly converting an expression to void via | |
814 | a cast. When non-NULL, IMPLICIT is a string indicating the context of | |
815 | the implicit conversion. */ | |
b1a8d4ce | 816 | |
817 | tree | |
ebd21de4 | 818 | convert_to_void (tree expr, const char *implicit, tsubst_flags_t complain) |
b1a8d4ce | 819 | { |
9031d10b | 820 | if (expr == error_mark_node |
3d411d73 | 821 | || TREE_TYPE (expr) == error_mark_node) |
822 | return error_mark_node; | |
b1a8d4ce | 823 | if (!TREE_TYPE (expr)) |
824 | return expr; | |
ebd21de4 | 825 | if (invalid_nonstatic_memfn_p (expr, complain)) |
334f6ce1 | 826 | return error_mark_node; |
ed36f1cf | 827 | if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR) |
828 | { | |
ebd21de4 | 829 | if (complain & tf_error) |
830 | error ("pseudo-destructor is not called"); | |
ed36f1cf | 831 | return error_mark_node; |
832 | } | |
e3cfe3ce | 833 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 834 | return expr; |
835 | switch (TREE_CODE (expr)) | |
836 | { | |
837 | case COND_EXPR: | |
838 | { | |
653e5405 | 839 | /* The two parts of a cond expr might be separate lvalues. */ |
840 | tree op1 = TREE_OPERAND (expr,1); | |
841 | tree op2 = TREE_OPERAND (expr,2); | |
7e34c19d | 842 | bool side_effects = TREE_SIDE_EFFECTS (op1) || TREE_SIDE_EFFECTS (op2); |
653e5405 | 843 | tree new_op1 = convert_to_void |
7e34c19d | 844 | (op1, (implicit && !side_effects |
ebd21de4 | 845 | ? "second operand of conditional" : NULL), complain); |
653e5405 | 846 | tree new_op2 = convert_to_void |
7e34c19d | 847 | (op2, (implicit && !side_effects |
ebd21de4 | 848 | ? "third operand of conditional" : NULL), complain); |
9031d10b | 849 | |
831d52a2 | 850 | expr = build3 (COND_EXPR, TREE_TYPE (new_op1), |
851 | TREE_OPERAND (expr, 0), new_op1, new_op2); | |
653e5405 | 852 | break; |
b1a8d4ce | 853 | } |
9031d10b | 854 | |
b1a8d4ce | 855 | case COMPOUND_EXPR: |
856 | { | |
653e5405 | 857 | /* The second part of a compound expr contains the value. */ |
858 | tree op1 = TREE_OPERAND (expr,1); | |
859 | tree new_op1 = convert_to_void | |
4ee9c684 | 860 | (op1, (implicit && !TREE_NO_WARNING (expr) |
ebd21de4 | 861 | ? "right-hand operand of comma" : NULL), complain); |
9031d10b | 862 | |
653e5405 | 863 | if (new_op1 != op1) |
e907a2e9 | 864 | { |
831d52a2 | 865 | tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1), |
866 | TREE_OPERAND (expr, 0), new_op1); | |
e907a2e9 | 867 | expr = t; |
868 | } | |
869 | ||
653e5405 | 870 | break; |
b1a8d4ce | 871 | } |
9031d10b | 872 | |
b1a8d4ce | 873 | case NON_LVALUE_EXPR: |
874 | case NOP_EXPR: | |
c0af329c | 875 | /* These have already decayed to rvalue. */ |
b1a8d4ce | 876 | break; |
9031d10b | 877 | |
331bc0ad | 878 | case CALL_EXPR: /* We have a special meaning for volatile void fn(). */ |
b1a8d4ce | 879 | break; |
9031d10b | 880 | |
b1a8d4ce | 881 | case INDIRECT_REF: |
882 | { | |
653e5405 | 883 | tree type = TREE_TYPE (expr); |
884 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
885 | == REFERENCE_TYPE; | |
886 | int is_volatile = TYPE_VOLATILE (type); | |
887 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
888 | ||
dc02da7f | 889 | /* Can't load the value if we don't know the type. */ |
653e5405 | 890 | if (is_volatile && !is_complete) |
ebd21de4 | 891 | { |
892 | if (complain & tf_warning) | |
893 | warning (0, "object of incomplete type %qT will not be accessed in %s", | |
894 | type, implicit ? implicit : "void context"); | |
895 | } | |
dc02da7f | 896 | /* Don't load the value if this is an implicit dereference, or if |
897 | the type needs to be handled by ctors/dtors. */ | |
898 | else if (is_volatile && (is_reference || TREE_ADDRESSABLE (type))) | |
ebd21de4 | 899 | { |
900 | if (complain & tf_warning) | |
901 | warning (0, "object of type %qT will not be accessed in %s", | |
902 | TREE_TYPE (TREE_OPERAND (expr, 0)), | |
903 | implicit ? implicit : "void context"); | |
904 | } | |
dc02da7f | 905 | if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type)) |
a4d4030b | 906 | { |
907 | /* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF | |
908 | operation is stripped off. Note that we don't warn about | |
909 | - an expression with TREE_NO_WARNING set. (For an example of | |
910 | such expressions, see build_over_call in call.c.) | |
911 | - automatic dereferencing of references, since the user cannot | |
912 | control it. (See also warn_if_unused_value() in stmt.c.) */ | |
913 | if (warn_unused_value | |
f8646185 | 914 | && implicit |
a4d4030b | 915 | && (complain & tf_warning) |
916 | && !TREE_NO_WARNING (expr) | |
917 | && !is_reference) | |
918 | warning (OPT_Wunused_value, "value computed is not used"); | |
919 | expr = TREE_OPERAND (expr, 0); | |
920 | } | |
653e5405 | 921 | |
922 | break; | |
b1a8d4ce | 923 | } |
9031d10b | 924 | |
b1a8d4ce | 925 | case VAR_DECL: |
926 | { | |
653e5405 | 927 | /* External variables might be incomplete. */ |
928 | tree type = TREE_TYPE (expr); | |
929 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
930 | ||
ebd21de4 | 931 | if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning)) |
653e5405 | 932 | warning (0, "object %qE of incomplete type %qT will not be accessed in %s", |
933 | expr, type, implicit ? implicit : "void context"); | |
934 | break; | |
b1a8d4ce | 935 | } |
d9f88785 | 936 | |
25b3017b | 937 | case TARGET_EXPR: |
938 | /* Don't bother with the temporary object returned from a function if | |
939 | we don't use it and don't need to destroy it. We'll still | |
940 | allocate space for it in expand_call or declare_return_variable, | |
941 | but we don't need to track it through all the tree phases. */ | |
67bb1301 | 942 | if (TARGET_EXPR_IMPLICIT_P (expr) |
25b3017b | 943 | && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr))) |
944 | { | |
945 | tree init = TARGET_EXPR_INITIAL (expr); | |
946 | if (TREE_CODE (init) == AGGR_INIT_EXPR | |
947 | && !AGGR_INIT_VIA_CTOR_P (init)) | |
948 | { | |
c2f47e15 | 949 | tree fn = AGGR_INIT_EXPR_FN (init); |
389dd41b | 950 | expr = build_call_array_loc (input_location, |
951 | TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))), | |
952 | fn, | |
953 | aggr_init_expr_nargs (init), | |
954 | AGGR_INIT_EXPR_ARGP (init)); | |
25b3017b | 955 | } |
956 | } | |
957 | break; | |
958 | ||
b1a8d4ce | 959 | default:; |
960 | } | |
eebd67e7 | 961 | expr = resolve_nondeduced_context (expr); |
b1a8d4ce | 962 | { |
963 | tree probe = expr; | |
9031d10b | 964 | |
b1a8d4ce | 965 | if (TREE_CODE (probe) == ADDR_EXPR) |
966 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 967 | if (type_unknown_p (probe)) |
968 | { | |
969 | /* [over.over] enumerates the places where we can take the address | |
970 | of an overloaded function, and this is not one of them. */ | |
ebd21de4 | 971 | if (complain & tf_error) |
972 | error ("%s cannot resolve address of overloaded function", | |
973 | implicit ? implicit : "void cast"); | |
974 | else | |
975 | return error_mark_node; | |
ea720917 | 976 | expr = void_zero_node; |
2e0e6579 | 977 | } |
978 | else if (implicit && probe == expr && is_overloaded_fn (probe)) | |
2056769e | 979 | { |
980 | /* Only warn when there is no &. */ | |
ebd21de4 | 981 | if (complain & tf_warning) |
982 | warning (OPT_Waddress, "%s is a reference, not call, to function %qE", | |
983 | implicit, expr); | |
2056769e | 984 | if (TREE_CODE (expr) == COMPONENT_REF) |
985 | expr = TREE_OPERAND (expr, 0); | |
986 | } | |
b1a8d4ce | 987 | } |
9031d10b | 988 | |
e3cfe3ce | 989 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 990 | { |
5e2a4133 | 991 | if (implicit |
992 | && warn_unused_value | |
993 | && !TREE_NO_WARNING (expr) | |
994 | && !processing_template_decl) | |
1fe46df1 | 995 | { |
996 | /* The middle end does not warn about expressions that have | |
997 | been explicitly cast to void, so we must do so here. */ | |
ebd21de4 | 998 | if (!TREE_SIDE_EFFECTS (expr)) { |
999 | if (complain & tf_warning) | |
1000 | warning (OPT_Wunused_value, "%s has no effect", implicit); | |
1001 | } | |
9031d10b | 1002 | else |
1003 | { | |
1fe46df1 | 1004 | tree e; |
1005 | enum tree_code code; | |
607a5d68 | 1006 | enum tree_code_class tclass; |
9031d10b | 1007 | |
1fe46df1 | 1008 | e = expr; |
1009 | /* We might like to warn about (say) "(int) f()", as the | |
1010 | cast has no effect, but the compiler itself will | |
1011 | generate implicit conversions under some | |
324d8f2d | 1012 | circumstances. (For example a block copy will be |
1fe46df1 | 1013 | turned into a call to "__builtin_memcpy", with a |
1014 | conversion of the return value to an appropriate | |
1015 | type.) So, to avoid false positives, we strip | |
416ce344 | 1016 | conversions. Do not use STRIP_NOPs because it will |
1017 | not strip conversions to "void", as that is not a | |
1018 | mode-preserving conversion. */ | |
1019 | while (TREE_CODE (e) == NOP_EXPR) | |
1020 | e = TREE_OPERAND (e, 0); | |
1fe46df1 | 1021 | |
1022 | code = TREE_CODE (e); | |
607a5d68 | 1023 | tclass = TREE_CODE_CLASS (code); |
1024 | if ((tclass == tcc_comparison | |
1025 | || tclass == tcc_unary | |
1026 | || (tclass == tcc_binary | |
1fe46df1 | 1027 | && !(code == MODIFY_EXPR |
1028 | || code == INIT_EXPR | |
1029 | || code == PREDECREMENT_EXPR | |
1030 | || code == PREINCREMENT_EXPR | |
1031 | || code == POSTDECREMENT_EXPR | |
1032 | || code == POSTINCREMENT_EXPR))) | |
ebd21de4 | 1033 | && (complain & tf_warning)) |
ced7c954 | 1034 | warning (OPT_Wunused_value, "value computed is not used"); |
1fe46df1 | 1035 | } |
1036 | } | |
00fa9079 | 1037 | expr = build1 (CONVERT_EXPR, void_type_node, expr); |
b1a8d4ce | 1038 | } |
de5ad4cb | 1039 | if (! TREE_SIDE_EFFECTS (expr)) |
1040 | expr = void_zero_node; | |
b1a8d4ce | 1041 | return expr; |
1042 | } | |
1043 | ||
d81e00a4 | 1044 | /* Create an expression whose value is that of EXPR, |
1045 | converted to type TYPE. The TREE_TYPE of the value | |
1046 | is always TYPE. This function implements all reasonable | |
1047 | conversions; callers should filter out those that are | |
c4a8ac95 | 1048 | not permitted by the language being compiled. |
1049 | ||
1050 | Most of this routine is from build_reinterpret_cast. | |
1051 | ||
a17c2a3a | 1052 | The back end cannot call cp_convert (what was convert) because |
c4a8ac95 | 1053 | conversions to/from basetypes may involve memory references |
1054 | (vbases) and adding or subtracting small values (multiple | |
1055 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 1056 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 1057 | |
1058 | Also, if we ever support range variables, we'll probably also have to | |
1059 | do a little bit more work. */ | |
d81e00a4 | 1060 | |
1061 | tree | |
35771a9a | 1062 | convert (tree type, tree expr) |
d81e00a4 | 1063 | { |
c4a8ac95 | 1064 | tree intype; |
1065 | ||
1066 | if (type == error_mark_node || expr == error_mark_node) | |
1067 | return error_mark_node; | |
1068 | ||
c4a8ac95 | 1069 | intype = TREE_TYPE (expr); |
1070 | ||
6686e84d | 1071 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
13f0eb20 | 1072 | return fold_if_not_in_template (build_nop (type, expr)); |
c4a8ac95 | 1073 | |
1074 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
1075 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); | |
d81e00a4 | 1076 | } |
1077 | ||
c4a8ac95 | 1078 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 1079 | are not normally allowed due to access restrictions |
1080 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 1081 | |
471086d6 | 1082 | tree |
35771a9a | 1083 | convert_force (tree type, tree expr, int convtype) |
471086d6 | 1084 | { |
cd16867a | 1085 | tree e = expr; |
1086 | enum tree_code code = TREE_CODE (type); | |
471086d6 | 1087 | |
1088 | if (code == REFERENCE_TYPE) | |
9031d10b | 1089 | return (fold_if_not_in_template |
5d7ed6c7 | 1090 | (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, |
1091 | NULL_TREE))); | |
471086d6 | 1092 | |
1093 | if (code == POINTER_TYPE) | |
5d7ed6c7 | 1094 | return fold_if_not_in_template (convert_to_pointer_force (type, e)); |
471086d6 | 1095 | |
ac9386a0 | 1096 | /* From typeck.c convert_for_assignment */ |
471086d6 | 1097 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
1098 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
1099 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 1100 | || integer_zerop (e) |
1101 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1102 | && TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 1103 | /* compatible pointer to member functions. */ |
1104 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1, | |
1105 | /*c_cast_p=*/1); | |
a74e8896 | 1106 | |
c4a8ac95 | 1107 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
471086d6 | 1108 | } |
1109 | ||
471086d6 | 1110 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1111 | exists, return the attempted conversion. This may | |
1112 | return ERROR_MARK_NODE if the conversion is not | |
1113 | allowed (references private members, etc). | |
1114 | If no conversion exists, NULL_TREE is returned. | |
1115 | ||
ce28ee2e | 1116 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit |
1117 | object parameter, or by the second standard conversion sequence if | |
1118 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1119 | (jason 8/9/95) */ | |
471086d6 | 1120 | |
ef9571e5 | 1121 | static tree |
8999978b | 1122 | build_type_conversion (tree xtype, tree expr) |
471086d6 | 1123 | { |
1124 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1125 | into the required type. */ |
8999978b | 1126 | return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL); |
471086d6 | 1127 | } |
1128 | ||
1e66592c | 1129 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1130 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
35771a9a | 1131 | which indicates which types are suitable. If COMPLAIN is true, complain |
1e66592c | 1132 | about ambiguity; otherwise, the caller will deal with it. */ |
471086d6 | 1133 | |
1e66592c | 1134 | tree |
35771a9a | 1135 | build_expr_type_conversion (int desires, tree expr, bool complain) |
471086d6 | 1136 | { |
1e66592c | 1137 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1138 | tree conv = NULL_TREE; |
bdd152ce | 1139 | tree winner = NULL_TREE; |
471086d6 | 1140 | |
9031d10b | 1141 | if (expr == null_node |
1142 | && (desires & WANT_INT) | |
954885ed | 1143 | && !(desires & WANT_NULL)) |
8296fdaa | 1144 | warning_at (input_location, OPT_Wconversion_null, |
1145 | "converting NULL to non-pointer type"); | |
9031d10b | 1146 | |
ce28ee2e | 1147 | basetype = TREE_TYPE (expr); |
471086d6 | 1148 | |
3d411d73 | 1149 | if (basetype == error_mark_node) |
1150 | return error_mark_node; | |
1151 | ||
95397ff9 | 1152 | if (! MAYBE_CLASS_TYPE_P (basetype)) |
bdd152ce | 1153 | switch (TREE_CODE (basetype)) |
1154 | { | |
1155 | case INTEGER_TYPE: | |
954885ed | 1156 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1157 | return expr; |
1158 | /* else fall through... */ | |
1159 | ||
1160 | case BOOLEAN_TYPE: | |
1161 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1162 | case ENUMERAL_TYPE: | |
1163 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1164 | case REAL_TYPE: | |
1165 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1166 | case POINTER_TYPE: | |
1167 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
9031d10b | 1168 | |
bdd152ce | 1169 | case FUNCTION_TYPE: |
1170 | case ARRAY_TYPE: | |
a681799d | 1171 | return (desires & WANT_POINTER) ? decay_conversion (expr) |
653e5405 | 1172 | : NULL_TREE; |
96ec9e30 | 1173 | |
64ec1ad6 | 1174 | case COMPLEX_TYPE: |
96ec9e30 | 1175 | case VECTOR_TYPE: |
64ec1ad6 | 1176 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1177 | return NULL_TREE; |
1178 | switch (TREE_CODE (TREE_TYPE (basetype))) | |
1179 | { | |
1180 | case INTEGER_TYPE: | |
1181 | case BOOLEAN_TYPE: | |
1182 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1183 | case ENUMERAL_TYPE: | |
1184 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1185 | case REAL_TYPE: | |
1186 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1187 | default: | |
1188 | return NULL_TREE; | |
1189 | } | |
1190 | ||
bdd152ce | 1191 | default: |
1192 | return NULL_TREE; | |
1193 | } | |
1194 | ||
1195 | /* The code for conversions from class type is currently only used for | |
1196 | delete expressions. Other expressions are handled by build_new_op. */ | |
f8182e08 | 1197 | if (!complete_type_or_else (basetype, expr)) |
1198 | return error_mark_node; | |
1199 | if (!TYPE_HAS_CONVERSION (basetype)) | |
bdd152ce | 1200 | return NULL_TREE; |
1201 | ||
8972df28 | 1202 | for (conv = lookup_conversions (basetype, /*lookup_template_convs_p=*/true); |
1203 | conv; | |
1204 | conv = TREE_CHAIN (conv)) | |
bdd152ce | 1205 | { |
1206 | int win = 0; | |
1207 | tree candidate; | |
1208 | tree cand = TREE_VALUE (conv); | |
c1ca2f12 | 1209 | cand = OVL_CURRENT (cand); |
bdd152ce | 1210 | |
1211 | if (winner && winner == cand) | |
1212 | continue; | |
1213 | ||
cf7aa2e5 | 1214 | if (DECL_NONCONVERTING_P (cand)) |
1215 | continue; | |
1216 | ||
ef4534a3 | 1217 | candidate = non_reference (TREE_TYPE (TREE_TYPE (cand))); |
bdd152ce | 1218 | |
1219 | switch (TREE_CODE (candidate)) | |
1220 | { | |
1221 | case BOOLEAN_TYPE: | |
1222 | case INTEGER_TYPE: | |
1223 | win = (desires & WANT_INT); break; | |
1224 | case ENUMERAL_TYPE: | |
1225 | win = (desires & WANT_ENUM); break; | |
1226 | case REAL_TYPE: | |
1227 | win = (desires & WANT_FLOAT); break; | |
1228 | case POINTER_TYPE: | |
1229 | win = (desires & WANT_POINTER); break; | |
1230 | ||
64ec1ad6 | 1231 | case COMPLEX_TYPE: |
96ec9e30 | 1232 | case VECTOR_TYPE: |
64ec1ad6 | 1233 | if ((desires & WANT_VECTOR_OR_COMPLEX) == 0) |
96ec9e30 | 1234 | break; |
1235 | switch (TREE_CODE (TREE_TYPE (candidate))) | |
1236 | { | |
1237 | case BOOLEAN_TYPE: | |
1238 | case INTEGER_TYPE: | |
1239 | win = (desires & WANT_INT); break; | |
1240 | case ENUMERAL_TYPE: | |
1241 | win = (desires & WANT_ENUM); break; | |
1242 | case REAL_TYPE: | |
1243 | win = (desires & WANT_FLOAT); break; | |
1244 | default: | |
1245 | break; | |
1246 | } | |
1247 | break; | |
1248 | ||
bdd152ce | 1249 | default: |
1250 | break; | |
1251 | } | |
1252 | ||
1253 | if (win) | |
1254 | { | |
1255 | if (winner) | |
1256 | { | |
1257 | if (complain) | |
1258 | { | |
0a25aad6 | 1259 | error ("ambiguous default type conversion from %qT", |
653e5405 | 1260 | basetype); |
0a25aad6 | 1261 | error (" candidate conversions include %qD and %qD", |
653e5405 | 1262 | winner, cand); |
bdd152ce | 1263 | } |
1264 | return error_mark_node; | |
1265 | } | |
1266 | else | |
1267 | winner = cand; | |
1268 | } | |
1269 | } | |
1e66592c | 1270 | |
bdd152ce | 1271 | if (winner) |
1272 | { | |
ef4534a3 | 1273 | tree type = non_reference (TREE_TYPE (TREE_TYPE (winner))); |
bdd152ce | 1274 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL); |
471086d6 | 1275 | } |
1e66592c | 1276 | |
985e9ee0 | 1277 | return NULL_TREE; |
471086d6 | 1278 | } |
bc3887cf | 1279 | |
96624a9e | 1280 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1281 | ||
bc3887cf | 1282 | tree |
35771a9a | 1283 | type_promotes_to (tree type) |
bc3887cf | 1284 | { |
2b3c93a3 | 1285 | tree promoted_type; |
1286 | ||
ce28ee2e | 1287 | if (type == error_mark_node) |
1288 | return error_mark_node; | |
1289 | ||
bc3887cf | 1290 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1291 | |
2b3c93a3 | 1292 | /* Check for promotions of target-defined types first. */ |
1293 | promoted_type = targetm.promoted_type (type); | |
1294 | if (promoted_type) | |
1295 | return promoted_type; | |
1296 | ||
bb0726a1 | 1297 | /* bool always promotes to int (not unsigned), even if it's the same |
1298 | size. */ | |
9e1a8234 | 1299 | if (TREE_CODE (type) == BOOLEAN_TYPE) |
bb0726a1 | 1300 | type = integer_type_node; |
1301 | ||
1302 | /* Normally convert enums to int, but convert wide enums to something | |
1303 | wider. */ | |
1304 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
924bbf02 | 1305 | || type == char16_type_node |
1306 | || type == char32_type_node | |
bb0726a1 | 1307 | || type == wchar_type_node) |
6c9497b1 | 1308 | { |
1309 | int precision = MAX (TYPE_PRECISION (type), | |
1310 | TYPE_PRECISION (integer_type_node)); | |
771d21fa | 1311 | tree totype = c_common_type_for_size (precision, 0); |
78a8ed03 | 1312 | if (TYPE_UNSIGNED (type) |
6c9497b1 | 1313 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) |
771d21fa | 1314 | type = c_common_type_for_size (precision, 1); |
6c9497b1 | 1315 | else |
1316 | type = totype; | |
1317 | } | |
d7aeef06 | 1318 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1319 | { |
d0acef9e | 1320 | /* Retain unsignedness if really not getting bigger. */ |
78a8ed03 | 1321 | if (TYPE_UNSIGNED (type) |
d0acef9e | 1322 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1323 | type = unsigned_type_node; |
1324 | else | |
1325 | type = integer_type_node; | |
1326 | } | |
1327 | else if (type == float_type_node) | |
1328 | type = double_type_node; | |
9031d10b | 1329 | |
a681799d | 1330 | return type; |
bc3887cf | 1331 | } |
668ae905 | 1332 | |
668ae905 | 1333 | /* The routines below this point are carefully written to conform to |
1334 | the standard. They use the same terminology, and follow the rules | |
1335 | closely. Although they are used only in pt.c at the moment, they | |
1336 | should presumably be used everywhere in the future. */ | |
1337 | ||
1146f179 | 1338 | /* Attempt to perform qualification conversions on EXPR to convert it |
1339 | to TYPE. Return the resulting expression, or error_mark_node if | |
1340 | the conversion was impossible. */ | |
1341 | ||
9031d10b | 1342 | tree |
35771a9a | 1343 | perform_qualification_conversions (tree type, tree expr) |
668ae905 | 1344 | { |
1bc16cab | 1345 | tree expr_type; |
1346 | ||
1347 | expr_type = TREE_TYPE (expr); | |
1348 | ||
3b087710 | 1349 | if (same_type_p (type, expr_type)) |
1350 | return expr; | |
1351 | else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type) | |
1352 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type))) | |
1bc16cab | 1353 | return build_nop (type, expr); |
1354 | else if (TYPE_PTR_TO_MEMBER_P (type) | |
1355 | && TYPE_PTR_TO_MEMBER_P (expr_type) | |
1356 | && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type), | |
1357 | TYPE_PTRMEM_CLASS_TYPE (expr_type)) | |
1358 | && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type), | |
1359 | TYPE_PTRMEM_POINTED_TO_TYPE (expr_type))) | |
1360 | return build_nop (type, expr); | |
1146f179 | 1361 | else |
1362 | return error_mark_node; | |
668ae905 | 1363 | } |