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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, |
a33e06b7 | 3 | 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. |
471086d6 | 4 | Hacked by Michael Tiemann (tiemann@cygnus.com) |
5 | ||
6f0d25a6 | 6 | This file is part of GCC. |
471086d6 | 7 | |
6f0d25a6 | 8 | GCC is free software; you can redistribute it and/or modify |
471086d6 | 9 | it under the terms of the GNU General Public License as published by |
10 | the Free Software Foundation; either version 2, or (at your option) | |
11 | any later version. | |
12 | ||
6f0d25a6 | 13 | GCC is distributed in the hope that it will be useful, |
471086d6 | 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
6f0d25a6 | 19 | along with GCC; see the file COPYING. If not, write to |
beaeca68 | 20 | the Free Software Foundation, 51 Franklin Street, Fifth Floor, |
21 | Boston, MA 02110-1301, USA. */ | |
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" | |
471086d6 | 36 | #include "convert.h" |
f0eaeecd | 37 | #include "toplev.h" |
2e8226f7 | 38 | #include "decl.h" |
7a979707 | 39 | #include "target.h" |
96624a9e | 40 | |
35771a9a | 41 | static tree cp_convert_to_pointer (tree, tree, bool); |
42 | static tree convert_to_pointer_force (tree, tree); | |
ef9571e5 | 43 | static tree build_type_conversion (tree, tree); |
35771a9a | 44 | static tree build_up_reference (tree, tree, int, tree); |
45 | static void warn_ref_binding (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 | |
045ed8f8 | 74 | else try C-style pointer conversion. If FORCE is true then allow |
75 | conversions via virtual bases (these are permitted by reinterpret_cast, | |
76 | but not static_cast). */ | |
96624a9e | 77 | |
471086d6 | 78 | static tree |
35771a9a | 79 | cp_convert_to_pointer (tree type, tree expr, bool force) |
471086d6 | 80 | { |
cd16867a | 81 | tree intype = TREE_TYPE (expr); |
82 | enum tree_code form; | |
f82eeb87 | 83 | tree rval; |
8bf328bf | 84 | if (intype == error_mark_node) |
85 | return error_mark_node; | |
74002e1d | 86 | |
96624a9e | 87 | if (IS_AGGR_TYPE (intype)) |
88 | { | |
96624a9e | 89 | intype = complete_type (intype); |
4b72716d | 90 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 91 | { |
0a25aad6 | 92 | error ("can't convert from incomplete type %qT to %qT", |
653e5405 | 93 | intype, type); |
96624a9e | 94 | return error_mark_node; |
95 | } | |
96 | ||
8999978b | 97 | rval = build_type_conversion (type, expr); |
96624a9e | 98 | if (rval) |
99 | { | |
100 | if (rval == error_mark_node) | |
0a25aad6 | 101 | error ("conversion of %qE from %qT to %qT is ambiguous", |
653e5405 | 102 | expr, intype, type); |
96624a9e | 103 | return rval; |
104 | } | |
105 | } | |
106 | ||
860740a7 | 107 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 108 | if (TREE_CODE (type) == POINTER_TYPE |
109 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
e3cfe3ce | 110 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 111 | { |
6ab399e8 | 112 | if (TYPE_PTRMEMFUNC_P (intype) |
113 | || TREE_CODE (intype) == METHOD_TYPE) | |
114 | return convert_member_func_to_ptr (type, expr); | |
a63bc44c | 115 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) |
116 | return build_nop (type, expr); | |
38281c46 | 117 | intype = TREE_TYPE (expr); |
118 | } | |
119 | ||
311e42bc | 120 | if (expr == error_mark_node) |
121 | return error_mark_node; | |
122 | ||
74002e1d | 123 | form = TREE_CODE (intype); |
124 | ||
2b77484d | 125 | if (POINTER_TYPE_P (intype)) |
471086d6 | 126 | { |
127 | intype = TYPE_MAIN_VARIANT (intype); | |
128 | ||
129 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 130 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 131 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
bccffb3a | 132 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
133 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
4a2680fc | 134 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
471086d6 | 135 | { |
136 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 137 | tree binfo; |
8999978b | 138 | tree intype_class; |
139 | tree type_class; | |
140 | bool same_p; | |
4a2680fc | 141 | |
8999978b | 142 | intype_class = TREE_TYPE (intype); |
143 | type_class = TREE_TYPE (type); | |
144 | ||
9031d10b | 145 | same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class), |
8999978b | 146 | TYPE_MAIN_VARIANT (type_class)); |
147 | binfo = NULL_TREE; | |
c0af329c | 148 | /* Try derived to base conversion. */ |
8999978b | 149 | if (!same_p) |
150 | binfo = lookup_base (intype_class, type_class, ba_check, NULL); | |
151 | if (!same_p && !binfo) | |
471086d6 | 152 | { |
c0af329c | 153 | /* Try base to derived conversion. */ |
8999978b | 154 | binfo = lookup_base (type_class, intype_class, ba_check, NULL); |
471086d6 | 155 | code = MINUS_EXPR; |
156 | } | |
4a2680fc | 157 | if (binfo == error_mark_node) |
158 | return error_mark_node; | |
8999978b | 159 | if (binfo || same_p) |
471086d6 | 160 | { |
8999978b | 161 | if (binfo) |
162 | expr = build_base_path (code, expr, binfo, 0); | |
c0af329c | 163 | /* Add any qualifier conversions. */ |
8999978b | 164 | return build_nop (type, expr); |
471086d6 | 165 | } |
166 | } | |
471086d6 | 167 | |
1bc16cab | 168 | if (TYPE_PTRMEMFUNC_P (type)) |
bea7d742 | 169 | { |
0a25aad6 | 170 | error ("cannot convert %qE from type %qT to type %qT", |
653e5405 | 171 | expr, intype, type); |
1bc16cab | 172 | return error_mark_node; |
173 | } | |
a17aefa2 | 174 | |
1bc16cab | 175 | return build_nop (type, expr); |
176 | } | |
177 | else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) | |
178 | { | |
9031d10b | 179 | tree b1; |
1bc16cab | 180 | tree b2; |
181 | tree binfo; | |
182 | enum tree_code code = PLUS_EXPR; | |
183 | base_kind bk; | |
184 | ||
185 | b1 = TYPE_PTRMEM_CLASS_TYPE (type); | |
186 | b2 = TYPE_PTRMEM_CLASS_TYPE (intype); | |
187 | binfo = lookup_base (b1, b2, ba_check, &bk); | |
188 | if (!binfo) | |
189 | { | |
190 | binfo = lookup_base (b2, b1, ba_check, &bk); | |
191 | code = MINUS_EXPR; | |
192 | } | |
193 | if (binfo == error_mark_node) | |
194 | return error_mark_node; | |
a17aefa2 | 195 | |
1bc16cab | 196 | if (bk == bk_via_virtual) |
197 | { | |
198 | if (force) | |
c3ceba8e | 199 | warning (0, "pointer to member cast from %qT to %qT is via" |
653e5405 | 200 | " virtual base", intype, type); |
1bc16cab | 201 | else |
7045d67a | 202 | { |
0a25aad6 | 203 | error ("pointer to member cast from %qT to %qT is" |
653e5405 | 204 | " via virtual base", intype, type); |
1bc16cab | 205 | return error_mark_node; |
7045d67a | 206 | } |
1bc16cab | 207 | /* This is a reinterpret cast, whose result is unspecified. |
208 | We choose to do nothing. */ | |
209 | return build1 (NOP_EXPR, type, expr); | |
ce28ee2e | 210 | } |
211 | ||
1bc16cab | 212 | if (TREE_CODE (expr) == PTRMEM_CST) |
213 | expr = cplus_expand_constant (expr); | |
214 | ||
215 | if (binfo && !integer_zerop (BINFO_OFFSET (binfo))) | |
9031d10b | 216 | expr = size_binop (code, |
1bc16cab | 217 | build_nop (sizetype, expr), |
218 | BINFO_OFFSET (binfo)); | |
8999978b | 219 | return build_nop (type, expr); |
471086d6 | 220 | } |
2b77484d | 221 | else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)) |
cb02169c | 222 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
223 | /*c_cast_p=*/false); | |
2b77484d | 224 | else if (TYPE_PTRMEMFUNC_P (intype)) |
225 | { | |
a63bc44c | 226 | if (!warn_pmf2ptr) |
227 | { | |
228 | if (TREE_CODE (expr) == PTRMEM_CST) | |
229 | return cp_convert_to_pointer (type, | |
230 | PTRMEM_CST_MEMBER (expr), | |
231 | force); | |
232 | else if (TREE_CODE (expr) == OFFSET_REF) | |
233 | { | |
234 | tree object = TREE_OPERAND (expr, 0); | |
235 | return get_member_function_from_ptrfunc (&object, | |
236 | TREE_OPERAND (expr, 1)); | |
237 | } | |
238 | } | |
0a25aad6 | 239 | error ("cannot convert %qE from type %qT to type %qT", |
653e5405 | 240 | expr, intype, type); |
2b77484d | 241 | return error_mark_node; |
242 | } | |
471086d6 | 243 | |
471086d6 | 244 | if (integer_zerop (expr)) |
245 | { | |
2b77484d | 246 | if (TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 247 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
248 | /*c_cast_p=*/false); | |
ad63a0fc | 249 | |
606b494c | 250 | if (TYPE_PTRMEM_P (type)) |
7c446c95 | 251 | { |
252 | /* A NULL pointer-to-member is represented by -1, not by | |
253 | zero. */ | |
7016c612 | 254 | expr = build_int_cst (type, -1); |
7c446c95 | 255 | /* Fix up the representation of -1 if appropriate. */ |
256 | expr = force_fit_type (expr, 0, false, false); | |
257 | } | |
ad63a0fc | 258 | else |
7016c612 | 259 | expr = build_int_cst (type, 0); |
9031d10b | 260 | |
471086d6 | 261 | return expr; |
262 | } | |
1bc16cab | 263 | else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form)) |
de1f960a | 264 | { |
0a25aad6 | 265 | error ("invalid conversion from %qT to %qT", intype, type); |
de1f960a | 266 | return error_mark_node; |
267 | } | |
471086d6 | 268 | |
bb0726a1 | 269 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 270 | { |
c5aa1e92 | 271 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 272 | return build1 (CONVERT_EXPR, type, expr); |
771d21fa | 273 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr); |
092b1d6f | 274 | /* Modes may be different but sizes should be the same. There |
275 | is supposed to be some integral type that is the same width | |
276 | as a pointer. */ | |
277 | gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
278 | == GET_MODE_SIZE (TYPE_MODE (type))); | |
9031d10b | 279 | |
471086d6 | 280 | return convert_to_pointer (type, expr); |
281 | } | |
282 | ||
cc4d0855 | 283 | if (type_unknown_p (expr)) |
0fbca5e8 | 284 | return instantiate_type (type, expr, tf_warning_or_error); |
cc4d0855 | 285 | |
0a25aad6 | 286 | error ("cannot convert %qE from type %qT to type %qT", |
653e5405 | 287 | expr, intype, type); |
471086d6 | 288 | return error_mark_node; |
289 | } | |
290 | ||
291 | /* Like convert, except permit conversions to take place which | |
292 | are not normally allowed due to access restrictions | |
293 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 294 | |
471086d6 | 295 | static tree |
35771a9a | 296 | convert_to_pointer_force (tree type, tree expr) |
471086d6 | 297 | { |
cd16867a | 298 | tree intype = TREE_TYPE (expr); |
299 | enum tree_code form = TREE_CODE (intype); | |
9031d10b | 300 | |
471086d6 | 301 | if (form == POINTER_TYPE) |
302 | { | |
303 | intype = TYPE_MAIN_VARIANT (intype); | |
304 | ||
305 | if (TYPE_MAIN_VARIANT (type) != intype | |
306 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
bccffb3a | 307 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
308 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
471086d6 | 309 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
310 | { | |
311 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 312 | tree binfo; |
313 | ||
314 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
ada40935 | 315 | ba_unique, NULL); |
4a2680fc | 316 | if (!binfo) |
471086d6 | 317 | { |
4a2680fc | 318 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
ada40935 | 319 | ba_unique, NULL); |
4a2680fc | 320 | code = MINUS_EXPR; |
471086d6 | 321 | } |
4a2680fc | 322 | if (binfo == error_mark_node) |
323 | return error_mark_node; | |
324 | if (binfo) | |
471086d6 | 325 | { |
4a2680fc | 326 | expr = build_base_path (code, expr, binfo, 0); |
653e5405 | 327 | if (expr == error_mark_node) |
328 | return error_mark_node; | |
c0af329c | 329 | /* Add any qualifier conversions. */ |
4a2680fc | 330 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
331 | TREE_TYPE (type))) | |
8999978b | 332 | expr = build_nop (type, expr); |
4a2680fc | 333 | return expr; |
471086d6 | 334 | } |
471086d6 | 335 | } |
471086d6 | 336 | } |
337 | ||
35771a9a | 338 | return cp_convert_to_pointer (type, expr, true); |
471086d6 | 339 | } |
340 | ||
341 | /* We are passing something to a function which requires a reference. | |
342 | The type we are interested in is in TYPE. The initial | |
343 | value we have to begin with is in ARG. | |
344 | ||
345 | FLAGS controls how we manage access checking. | |
ca106ab1 | 346 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
347 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 348 | |
471086d6 | 349 | static tree |
35771a9a | 350 | build_up_reference (tree type, tree arg, int flags, tree decl) |
471086d6 | 351 | { |
c76251c1 | 352 | tree rval; |
0543e7a9 | 353 | tree argtype = TREE_TYPE (arg); |
471086d6 | 354 | tree target_type = TREE_TYPE (type); |
471086d6 | 355 | |
b4df430b | 356 | gcc_assert (TREE_CODE (type) == REFERENCE_TYPE); |
471086d6 | 357 | |
c76251c1 | 358 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 359 | { |
ca106ab1 | 360 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
361 | here because it needs to live as long as DECL. */ | |
c76251c1 | 362 | tree targ = arg; |
ca106ab1 | 363 | |
7c09476d | 364 | arg = make_temporary_var_for_ref_to_temp (decl, TREE_TYPE (arg)); |
c23ebfdd | 365 | |
366 | /* Process the initializer for the declaration. */ | |
38281c46 | 367 | DECL_INITIAL (arg) = targ; |
d91303a6 | 368 | cp_finish_decl (arg, targ, /*init_const_expr_p=*/false, NULL_TREE, |
011310f7 | 369 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 370 | } |
c76251c1 | 371 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
1d8e4310 | 372 | return get_target_expr (arg); |
1ad432f2 | 373 | |
ca106ab1 | 374 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 375 | address, transform all occurrences of the register, into a memory |
376 | reference we could win better. */ | |
c76251c1 | 377 | rval = build_unary_op (ADDR_EXPR, arg, 1); |
15e55420 | 378 | if (rval == error_mark_node) |
379 | return error_mark_node; | |
380 | ||
6686e84d | 381 | if ((flags & LOOKUP_PROTECT) |
382 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
383 | && IS_AGGR_TYPE (argtype) | |
384 | && IS_AGGR_TYPE (target_type)) | |
385 | { | |
7e6960e0 | 386 | /* We go through lookup_base for the access control. */ |
4a2680fc | 387 | tree binfo = lookup_base (argtype, target_type, ba_check, NULL); |
6686e84d | 388 | if (binfo == error_mark_node) |
389 | return error_mark_node; | |
390 | if (binfo == NULL_TREE) | |
391 | return error_not_base_type (target_type, argtype); | |
4a2680fc | 392 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1); |
6686e84d | 393 | } |
c76251c1 | 394 | else |
395 | rval | |
396 | = convert_to_pointer_force (build_pointer_type (target_type), rval); | |
8999978b | 397 | return build_nop (type, rval); |
471086d6 | 398 | } |
399 | ||
519ba62c | 400 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
401 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
402 | for diagnostics. | |
9031d10b | 403 | |
519ba62c | 404 | [dcl.init.ref] says that if an rvalue is used to |
405 | initialize a reference, then the reference must be to a | |
406 | non-volatile const type. */ | |
407 | ||
408 | static void | |
35771a9a | 409 | warn_ref_binding (tree reftype, tree intype, tree decl) |
519ba62c | 410 | { |
411 | tree ttl = TREE_TYPE (reftype); | |
9031d10b | 412 | |
519ba62c | 413 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) |
414 | { | |
415 | const char *msg; | |
416 | ||
417 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
0a25aad6 | 418 | msg = "initialization of volatile reference type %q#T from" |
653e5405 | 419 | " rvalue of type %qT"; |
519ba62c | 420 | else if (CP_TYPE_VOLATILE_P (ttl)) |
0a25aad6 | 421 | msg = "conversion to volatile reference type %q#T " |
653e5405 | 422 | " from rvalue of type %qT"; |
519ba62c | 423 | else if (decl) |
0a25aad6 | 424 | msg = "initialization of non-const reference type %q#T from" |
653e5405 | 425 | " rvalue of type %qT"; |
519ba62c | 426 | else |
0a25aad6 | 427 | msg = "conversion to non-const reference type %q#T from" |
653e5405 | 428 | " rvalue of type %qT"; |
519ba62c | 429 | |
cf103c6c | 430 | pedwarn (msg, reftype, intype); |
519ba62c | 431 | } |
432 | } | |
433 | ||
471086d6 | 434 | /* For C++: Only need to do one-level references, but cannot |
435 | get tripped up on signed/unsigned differences. | |
436 | ||
d81e00a4 | 437 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
438 | initialized. It can be error_mark_node if we don't know the _DECL but | |
439 | we know it's an initialization. */ | |
471086d6 | 440 | |
471086d6 | 441 | tree |
35771a9a | 442 | convert_to_reference (tree reftype, tree expr, int convtype, |
653e5405 | 443 | int flags, tree decl) |
471086d6 | 444 | { |
cd16867a | 445 | tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); |
446 | tree intype; | |
471086d6 | 447 | tree rval = NULL_TREE; |
1a3f833b | 448 | tree rval_as_conversion = NULL_TREE; |
1bc16cab | 449 | bool can_convert_intype_to_type; |
1a3f833b | 450 | |
9031d10b | 451 | if (TREE_CODE (type) == FUNCTION_TYPE |
d32df6a6 | 452 | && TREE_TYPE (expr) == unknown_type_node) |
9031d10b | 453 | expr = instantiate_type (type, expr, |
0a3b29ad | 454 | (flags & LOOKUP_COMPLAIN) |
0fbca5e8 | 455 | ? tf_warning_or_error : tf_none); |
0a3b29ad | 456 | |
457 | if (expr == error_mark_node) | |
458 | return error_mark_node; | |
459 | ||
460 | intype = TREE_TYPE (expr); | |
cc4d0855 | 461 | |
b4df430b | 462 | gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE); |
ab12ed55 | 463 | gcc_assert (TREE_CODE (reftype) == REFERENCE_TYPE); |
471086d6 | 464 | |
471086d6 | 465 | intype = TYPE_MAIN_VARIANT (intype); |
466 | ||
1bc16cab | 467 | can_convert_intype_to_type = can_convert (type, intype); |
468 | if (!can_convert_intype_to_type | |
469 | && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) | |
1a3f833b | 470 | && ! (flags & LOOKUP_NO_CONVERSION)) |
471 | { | |
472 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
473 | ||
0a4be248 | 474 | rval_as_conversion |
8999978b | 475 | = build_type_conversion (reftype, expr); |
1a3f833b | 476 | |
477 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
478 | && real_lvalue_p (rval_as_conversion)) | |
479 | { | |
480 | expr = rval_as_conversion; | |
481 | rval_as_conversion = NULL_TREE; | |
482 | intype = type; | |
1bc16cab | 483 | can_convert_intype_to_type = 1; |
1a3f833b | 484 | } |
485 | } | |
486 | ||
1bc16cab | 487 | if (((convtype & CONV_STATIC) && can_convert (intype, type)) |
488 | || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type)) | |
471086d6 | 489 | { |
471086d6 | 490 | if (flags & LOOKUP_COMPLAIN) |
491 | { | |
bc3887cf | 492 | tree ttl = TREE_TYPE (reftype); |
cb0ba4ec | 493 | tree ttr = lvalue_type (expr); |
471086d6 | 494 | |
519ba62c | 495 | if (! real_lvalue_p (expr)) |
496 | warn_ref_binding (reftype, intype, decl); | |
9031d10b | 497 | |
519ba62c | 498 | if (! (convtype & CONV_CONST) |
3e04bd45 | 499 | && !at_least_as_qualified_p (ttl, ttr)) |
0a25aad6 | 500 | pedwarn ("conversion from %qT to %qT discards qualifiers", |
653e5405 | 501 | ttr, reftype); |
0543e7a9 | 502 | } |
503 | ||
ca106ab1 | 504 | return build_up_reference (reftype, expr, flags, decl); |
471086d6 | 505 | } |
c07b1ad1 | 506 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 507 | { |
508 | /* When casting an lvalue to a reference type, just convert into | |
509 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 510 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 511 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 512 | |
3748625f | 513 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
653e5405 | 514 | meant. */ |
1a3f833b | 515 | if (TREE_CODE (intype) == POINTER_TYPE |
00952d10 | 516 | && (comptypes (TREE_TYPE (intype), type, |
517 | COMPARE_BASE | COMPARE_DERIVED))) | |
c3ceba8e | 518 | warning (0, "casting %qT to %qT does not dereference pointer", |
00952d10 | 519 | intype, reftype); |
9031d10b | 520 | |
0543e7a9 | 521 | rval = build_unary_op (ADDR_EXPR, expr, 0); |
522 | if (rval != error_mark_node) | |
985e9ee0 | 523 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
524 | rval, 0); | |
0543e7a9 | 525 | if (rval != error_mark_node) |
b0722fac | 526 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 527 | } |
0a4be248 | 528 | else |
860740a7 | 529 | { |
530 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
531 | "converting", 0, 0); | |
a66fe4cb | 532 | if (rval == NULL_TREE || rval == error_mark_node) |
533 | return rval; | |
519ba62c | 534 | warn_ref_binding (reftype, intype, decl); |
ca106ab1 | 535 | rval = build_up_reference (reftype, rval, flags, decl); |
860740a7 | 536 | } |
471086d6 | 537 | |
538 | if (rval) | |
539 | { | |
96624a9e | 540 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 541 | return rval; |
542 | } | |
543 | ||
b248d3f7 | 544 | if (flags & LOOKUP_COMPLAIN) |
0a25aad6 | 545 | error ("cannot convert type %qT to type %qT", intype, reftype); |
b248d3f7 | 546 | |
471086d6 | 547 | return error_mark_node; |
548 | } | |
549 | ||
550 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 551 | way down to its lowest form. */ |
552 | ||
471086d6 | 553 | tree |
35771a9a | 554 | convert_from_reference (tree val) |
471086d6 | 555 | { |
120c0017 | 556 | if (TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE) |
729f89ff | 557 | { |
558 | tree t = canonical_type_variant (TREE_TYPE (TREE_TYPE (val))); | |
559 | tree ref = build1 (INDIRECT_REF, t, val); | |
9031d10b | 560 | |
729f89ff | 561 | /* We *must* set TREE_READONLY when dereferencing a pointer to const, |
562 | so that we get the proper error message if the result is used | |
563 | to assign to. Also, &* is supposed to be a no-op. */ | |
564 | TREE_READONLY (ref) = CP_TYPE_CONST_P (t); | |
565 | TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); | |
566 | TREE_SIDE_EFFECTS (ref) | |
567 | = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val)); | |
568 | REFERENCE_REF_P (ref) = 1; | |
569 | val = ref; | |
570 | } | |
9031d10b | 571 | |
471086d6 | 572 | return val; |
573 | } | |
e5dab226 | 574 | |
575 | /* Really perform an lvalue-to-rvalue conversion, including copying an | |
576 | argument of class type into a temporary. */ | |
577 | ||
578 | tree | |
579 | force_rvalue (tree expr) | |
580 | { | |
581 | if (IS_AGGR_TYPE (TREE_TYPE (expr)) && TREE_CODE (expr) != TARGET_EXPR) | |
582 | expr = ocp_convert (TREE_TYPE (expr), expr, | |
583 | CONV_IMPLICIT|CONV_FORCE_TEMP, LOOKUP_NORMAL); | |
584 | else | |
585 | expr = decay_conversion (expr); | |
586 | ||
587 | return expr; | |
588 | } | |
471086d6 | 589 | \f |
c4a8ac95 | 590 | /* C++ conversions, preference to static cast conversions. */ |
591 | ||
592 | tree | |
35771a9a | 593 | cp_convert (tree type, tree expr) |
c4a8ac95 | 594 | { |
595 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); | |
596 | } | |
597 | ||
b248d3f7 | 598 | /* Conversion... |
599 | ||
600 | FLAGS indicates how we should behave. */ | |
601 | ||
471086d6 | 602 | tree |
35771a9a | 603 | ocp_convert (tree type, tree expr, int convtype, int flags) |
471086d6 | 604 | { |
cd16867a | 605 | tree e = expr; |
606 | enum tree_code code = TREE_CODE (type); | |
7a979707 | 607 | const char *invalid_conv_diag; |
471086d6 | 608 | |
1bc16cab | 609 | if (error_operand_p (e) || type == error_mark_node) |
471086d6 | 610 | return error_mark_node; |
d81e00a4 | 611 | |
5b592939 | 612 | complete_type (type); |
613 | complete_type (TREE_TYPE (expr)); | |
614 | ||
7a979707 | 615 | if ((invalid_conv_diag |
616 | = targetm.invalid_conversion (TREE_TYPE (expr), type))) | |
617 | { | |
618 | error (invalid_conv_diag); | |
619 | return error_mark_node; | |
620 | } | |
621 | ||
13f0eb20 | 622 | e = integral_constant_value (e); |
7745052b | 623 | |
2133b374 | 624 | if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP) |
625 | /* Some internal structures (vtable_entry_type, sigtbl_ptr_type) | |
626 | don't go through finish_struct, so they don't have the synthesized | |
627 | constructors. So don't force a temporary. */ | |
628 | && TYPE_HAS_CONSTRUCTOR (type)) | |
1a3f833b | 629 | /* We need a new temporary; don't take this shortcut. */; |
630 | else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) | |
ca23ec64 | 631 | { |
daf9ff67 | 632 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 633 | /* The call to fold will not always remove the NOP_EXPR as |
634 | might be expected, since if one of the types is a typedef; | |
755edffd | 635 | the comparison in fold is just equality of pointers, not a |
f699c174 | 636 | call to comptypes. We don't call fold in this case because |
637 | that can result in infinite recursion; fold will call | |
638 | convert, which will call ocp_convert, etc. */ | |
639 | return e; | |
372e0e29 | 640 | /* For complex data types, we need to perform componentwise |
653e5405 | 641 | conversion. */ |
372e0e29 | 642 | else if (TREE_CODE (type) == COMPLEX_TYPE) |
653e5405 | 643 | return fold_if_not_in_template (convert_to_complex (type, e)); |
bdb2219e | 644 | else if (TREE_CODE (e) == TARGET_EXPR) |
645 | { | |
646 | /* Don't build a NOP_EXPR of class type. Instead, change the | |
647 | type of the temporary. Only allow this for cv-qual changes, | |
648 | though. */ | |
092b1d6f | 649 | gcc_assert (same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (e)), |
650 | TYPE_MAIN_VARIANT (type))); | |
bdb2219e | 651 | TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type; |
652 | return e; | |
653 | } | |
ca23ec64 | 654 | else |
092b1d6f | 655 | { |
656 | /* We shouldn't be treating objects of ADDRESSABLE type as | |
657 | rvalues. */ | |
658 | gcc_assert (!TREE_ADDRESSABLE (type)); | |
5d7ed6c7 | 659 | return fold_if_not_in_template (build_nop (type, e)); |
092b1d6f | 660 | } |
ca23ec64 | 661 | } |
662 | ||
d81e00a4 | 663 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 664 | { |
b1a8d4ce | 665 | e = convert_to_void (e, /*implicit=*/NULL); |
aeef2be5 | 666 | return e; |
95b2ac55 | 667 | } |
d81e00a4 | 668 | |
bb0726a1 | 669 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 670 | { |
617abf06 | 671 | tree intype = TREE_TYPE (e); |
02d7f858 | 672 | /* enum = enum, enum = int, enum = float, (enum)pointer are all |
653e5405 | 673 | errors. */ |
723d9ad3 | 674 | if (TREE_CODE (type) == ENUMERAL_TYPE |
b312a686 | 675 | && (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype) |
653e5405 | 676 | || TREE_CODE (intype) == REAL_TYPE) |
b312a686 | 677 | && ! (convtype & CONV_STATIC)) |
678 | || TREE_CODE (intype) == POINTER_TYPE)) | |
471086d6 | 679 | { |
b312a686 | 680 | if (flags & LOOKUP_COMPLAIN) |
681 | pedwarn ("conversion from %q#T to %q#T", intype, type); | |
471086d6 | 682 | |
683 | if (flag_pedantic_errors) | |
684 | return error_mark_node; | |
685 | } | |
f3ba5c6a | 686 | if (IS_AGGR_TYPE (intype)) |
471086d6 | 687 | { |
688 | tree rval; | |
8999978b | 689 | rval = build_type_conversion (type, e); |
6495357a | 690 | if (rval) |
691 | return rval; | |
b248d3f7 | 692 | if (flags & LOOKUP_COMPLAIN) |
0a25aad6 | 693 | error ("%q#T used where a %qT was expected", intype, type); |
471086d6 | 694 | return error_mark_node; |
695 | } | |
bb0726a1 | 696 | if (code == BOOLEAN_TYPE) |
ce871053 | 697 | return cp_truthvalue_conversion (e); |
698 | ||
5d7ed6c7 | 699 | return fold_if_not_in_template (convert_to_integer (type, e)); |
471086d6 | 700 | } |
1bc16cab | 701 | if (POINTER_TYPE_P (type) || TYPE_PTR_TO_MEMBER_P (type)) |
5d7ed6c7 | 702 | return fold_if_not_in_template (cp_convert_to_pointer (type, e, false)); |
684b9d79 | 703 | if (code == VECTOR_TYPE) |
c37ff371 | 704 | { |
705 | tree in_vtype = TREE_TYPE (e); | |
706 | if (IS_AGGR_TYPE (in_vtype)) | |
707 | { | |
708 | tree ret_val; | |
709 | ret_val = build_type_conversion (type, e); | |
653e5405 | 710 | if (ret_val) |
711 | return ret_val; | |
712 | if (flags & LOOKUP_COMPLAIN) | |
713 | error ("%q#T used where a %qT was expected", in_vtype, type); | |
714 | return error_mark_node; | |
c37ff371 | 715 | } |
5d7ed6c7 | 716 | return fold_if_not_in_template (convert_to_vector (type, e)); |
c37ff371 | 717 | } |
c4a8ac95 | 718 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 719 | { |
720 | if (IS_AGGR_TYPE (TREE_TYPE (e))) | |
721 | { | |
722 | tree rval; | |
8999978b | 723 | rval = build_type_conversion (type, e); |
471086d6 | 724 | if (rval) |
725 | return rval; | |
726 | else | |
b248d3f7 | 727 | if (flags & LOOKUP_COMPLAIN) |
0a25aad6 | 728 | error ("%q#T used where a floating point value was expected", |
b248d3f7 | 729 | TREE_TYPE (e)); |
471086d6 | 730 | } |
c4a8ac95 | 731 | if (code == REAL_TYPE) |
5d7ed6c7 | 732 | return fold_if_not_in_template (convert_to_real (type, e)); |
c4a8ac95 | 733 | else if (code == COMPLEX_TYPE) |
5d7ed6c7 | 734 | return fold_if_not_in_template (convert_to_complex (type, e)); |
471086d6 | 735 | } |
736 | ||
737 | /* New C++ semantics: since assignment is now based on | |
738 | memberwise copying, if the rhs type is derived from the | |
739 | lhs type, then we may still do a conversion. */ | |
740 | if (IS_AGGR_TYPE_CODE (code)) | |
741 | { | |
742 | tree dtype = TREE_TYPE (e); | |
c25194fd | 743 | tree ctor = NULL_TREE; |
471086d6 | 744 | |
471086d6 | 745 | dtype = TYPE_MAIN_VARIANT (dtype); |
746 | ||
471086d6 | 747 | /* Conversion between aggregate types. New C++ semantics allow |
748 | objects of derived type to be cast to objects of base type. | |
749 | Old semantics only allowed this between pointers. | |
750 | ||
751 | There may be some ambiguity between using a constructor | |
752 | vs. using a type conversion operator when both apply. */ | |
753 | ||
0a4be248 | 754 | ctor = e; |
860740a7 | 755 | |
8c18e707 | 756 | if (abstract_virtuals_error (NULL_TREE, type)) |
757 | return error_mark_node; | |
6cbb4197 | 758 | |
0a4be248 | 759 | if ((flags & LOOKUP_ONLYCONVERTING) |
760 | && ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 761 | /* For copy-initialization, first we create a temp of the proper type |
762 | with a user-defined conversion sequence, then we direct-initialize | |
763 | the target with the temp (see [dcl.init]). */ | |
764 | ctor = build_user_type_conversion (type, ctor, flags); | |
3eb89cd8 | 765 | else |
9031d10b | 766 | ctor = build_special_member_call (NULL_TREE, |
f70cb9e6 | 767 | complete_ctor_identifier, |
768 | build_tree_list (NULL_TREE, ctor), | |
a6460bf1 | 769 | type, flags); |
0a4be248 | 770 | if (ctor) |
771 | return build_cplus_new (type, ctor); | |
471086d6 | 772 | } |
773 | ||
b248d3f7 | 774 | if (flags & LOOKUP_COMPLAIN) |
0a25aad6 | 775 | error ("conversion from %qT to non-scalar type %qT requested", |
653e5405 | 776 | TREE_TYPE (expr), type); |
471086d6 | 777 | return error_mark_node; |
778 | } | |
779 | ||
b1a8d4ce | 780 | /* When an expression is used in a void context, its value is discarded and |
781 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
782 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
783 | in a void context. The C++ standard does not define what an `access' to an | |
63eff20d | 784 | object is, but there is reason to believe that it is the lvalue to rvalue |
b1a8d4ce | 785 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it |
786 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
787 | indicates that volatile semantics should be the same between C and C++ | |
788 | where ever possible. C leaves it implementation defined as to what | |
789 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
790 | the volatile object `vp' points to, unless that is an incomplete type. For | |
791 | volatile references we do not do this interpretation, because that would | |
792 | make it impossible to ignore the reference return value from functions. We | |
793 | issue warnings in the confusing cases. | |
9031d10b | 794 | |
b1a8d4ce | 795 | IMPLICIT is tells us the context of an implicit void conversion. */ |
796 | ||
797 | tree | |
35771a9a | 798 | convert_to_void (tree expr, const char *implicit) |
b1a8d4ce | 799 | { |
9031d10b | 800 | if (expr == error_mark_node |
3d411d73 | 801 | || TREE_TYPE (expr) == error_mark_node) |
802 | return error_mark_node; | |
b1a8d4ce | 803 | if (!TREE_TYPE (expr)) |
804 | return expr; | |
334f6ce1 | 805 | if (invalid_nonstatic_memfn_p (expr)) |
806 | return error_mark_node; | |
ed36f1cf | 807 | if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR) |
808 | { | |
809 | error ("pseudo-destructor is not called"); | |
810 | return error_mark_node; | |
811 | } | |
e3cfe3ce | 812 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 813 | return expr; |
814 | switch (TREE_CODE (expr)) | |
815 | { | |
816 | case COND_EXPR: | |
817 | { | |
653e5405 | 818 | /* The two parts of a cond expr might be separate lvalues. */ |
819 | tree op1 = TREE_OPERAND (expr,1); | |
820 | tree op2 = TREE_OPERAND (expr,2); | |
821 | tree new_op1 = convert_to_void | |
00fa9079 | 822 | (op1, (implicit && !TREE_SIDE_EFFECTS (op2) |
823 | ? "second operand of conditional" : NULL)); | |
653e5405 | 824 | tree new_op2 = convert_to_void |
00fa9079 | 825 | (op2, (implicit && !TREE_SIDE_EFFECTS (op1) |
826 | ? "third operand of conditional" : NULL)); | |
9031d10b | 827 | |
831d52a2 | 828 | expr = build3 (COND_EXPR, TREE_TYPE (new_op1), |
829 | TREE_OPERAND (expr, 0), new_op1, new_op2); | |
653e5405 | 830 | break; |
b1a8d4ce | 831 | } |
9031d10b | 832 | |
b1a8d4ce | 833 | case COMPOUND_EXPR: |
834 | { | |
653e5405 | 835 | /* The second part of a compound expr contains the value. */ |
836 | tree op1 = TREE_OPERAND (expr,1); | |
837 | tree new_op1 = convert_to_void | |
4ee9c684 | 838 | (op1, (implicit && !TREE_NO_WARNING (expr) |
23ec9bd9 | 839 | ? "right-hand operand of comma" : NULL)); |
9031d10b | 840 | |
653e5405 | 841 | if (new_op1 != op1) |
e907a2e9 | 842 | { |
831d52a2 | 843 | tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1), |
844 | TREE_OPERAND (expr, 0), new_op1); | |
e907a2e9 | 845 | expr = t; |
846 | } | |
847 | ||
653e5405 | 848 | break; |
b1a8d4ce | 849 | } |
9031d10b | 850 | |
b1a8d4ce | 851 | case NON_LVALUE_EXPR: |
852 | case NOP_EXPR: | |
c0af329c | 853 | /* These have already decayed to rvalue. */ |
b1a8d4ce | 854 | break; |
9031d10b | 855 | |
331bc0ad | 856 | case CALL_EXPR: /* We have a special meaning for volatile void fn(). */ |
b1a8d4ce | 857 | break; |
9031d10b | 858 | |
b1a8d4ce | 859 | case INDIRECT_REF: |
860 | { | |
653e5405 | 861 | tree type = TREE_TYPE (expr); |
862 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
863 | == REFERENCE_TYPE; | |
864 | int is_volatile = TYPE_VOLATILE (type); | |
865 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
866 | ||
dc02da7f | 867 | /* Can't load the value if we don't know the type. */ |
653e5405 | 868 | if (is_volatile && !is_complete) |
869 | warning (0, "object of incomplete type %qT will not be accessed in %s", | |
870 | type, implicit ? implicit : "void context"); | |
dc02da7f | 871 | /* Don't load the value if this is an implicit dereference, or if |
872 | the type needs to be handled by ctors/dtors. */ | |
873 | else if (is_volatile && (is_reference || TREE_ADDRESSABLE (type))) | |
653e5405 | 874 | warning (0, "object of type %qT will not be accessed in %s", |
875 | TREE_TYPE (TREE_OPERAND (expr, 0)), | |
876 | implicit ? implicit : "void context"); | |
dc02da7f | 877 | if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type)) |
653e5405 | 878 | expr = TREE_OPERAND (expr, 0); |
879 | ||
880 | break; | |
b1a8d4ce | 881 | } |
9031d10b | 882 | |
b1a8d4ce | 883 | case VAR_DECL: |
884 | { | |
653e5405 | 885 | /* External variables might be incomplete. */ |
886 | tree type = TREE_TYPE (expr); | |
887 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); | |
888 | ||
889 | if (TYPE_VOLATILE (type) && !is_complete) | |
890 | warning (0, "object %qE of incomplete type %qT will not be accessed in %s", | |
891 | expr, type, implicit ? implicit : "void context"); | |
892 | break; | |
b1a8d4ce | 893 | } |
d9f88785 | 894 | |
25b3017b | 895 | case TARGET_EXPR: |
896 | /* Don't bother with the temporary object returned from a function if | |
897 | we don't use it and don't need to destroy it. We'll still | |
898 | allocate space for it in expand_call or declare_return_variable, | |
899 | but we don't need to track it through all the tree phases. */ | |
900 | if (0 && TARGET_EXPR_IMPLICIT_P (expr) | |
901 | && TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr))) | |
902 | { | |
903 | tree init = TARGET_EXPR_INITIAL (expr); | |
904 | if (TREE_CODE (init) == AGGR_INIT_EXPR | |
905 | && !AGGR_INIT_VIA_CTOR_P (init)) | |
906 | { | |
907 | tree fn = TREE_OPERAND (init, 0); | |
908 | expr = build3 (CALL_EXPR, TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))), | |
909 | fn, TREE_OPERAND (init, 1), NULL_TREE); | |
910 | } | |
911 | } | |
912 | break; | |
913 | ||
b1a8d4ce | 914 | default:; |
915 | } | |
916 | { | |
917 | tree probe = expr; | |
9031d10b | 918 | |
b1a8d4ce | 919 | if (TREE_CODE (probe) == ADDR_EXPR) |
920 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 921 | if (type_unknown_p (probe)) |
922 | { | |
923 | /* [over.over] enumerates the places where we can take the address | |
924 | of an overloaded function, and this is not one of them. */ | |
cf103c6c | 925 | pedwarn ("%s cannot resolve address of overloaded function", |
2e0e6579 | 926 | implicit ? implicit : "void cast"); |
ea720917 | 927 | expr = void_zero_node; |
2e0e6579 | 928 | } |
929 | else if (implicit && probe == expr && is_overloaded_fn (probe)) | |
b1a8d4ce | 930 | /* Only warn when there is no &. */ |
c3ceba8e | 931 | warning (0, "%s is a reference, not call, to function %qE", |
2e0e6579 | 932 | implicit, expr); |
b1a8d4ce | 933 | } |
9031d10b | 934 | |
e3cfe3ce | 935 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 936 | { |
5e2a4133 | 937 | if (implicit |
938 | && warn_unused_value | |
939 | && !TREE_NO_WARNING (expr) | |
940 | && !processing_template_decl) | |
1fe46df1 | 941 | { |
942 | /* The middle end does not warn about expressions that have | |
943 | been explicitly cast to void, so we must do so here. */ | |
944 | if (!TREE_SIDE_EFFECTS (expr)) | |
ced7c954 | 945 | warning (OPT_Wunused_value, "%s has no effect", implicit); |
9031d10b | 946 | else |
947 | { | |
1fe46df1 | 948 | tree e; |
949 | enum tree_code code; | |
950 | enum tree_code_class class; | |
9031d10b | 951 | |
1fe46df1 | 952 | e = expr; |
953 | /* We might like to warn about (say) "(int) f()", as the | |
954 | cast has no effect, but the compiler itself will | |
955 | generate implicit conversions under some | |
324d8f2d | 956 | circumstances. (For example a block copy will be |
1fe46df1 | 957 | turned into a call to "__builtin_memcpy", with a |
958 | conversion of the return value to an appropriate | |
959 | type.) So, to avoid false positives, we strip | |
416ce344 | 960 | conversions. Do not use STRIP_NOPs because it will |
961 | not strip conversions to "void", as that is not a | |
962 | mode-preserving conversion. */ | |
963 | while (TREE_CODE (e) == NOP_EXPR) | |
964 | e = TREE_OPERAND (e, 0); | |
1fe46df1 | 965 | |
966 | code = TREE_CODE (e); | |
967 | class = TREE_CODE_CLASS (code); | |
968 | if (class == tcc_comparison | |
969 | || class == tcc_unary | |
9031d10b | 970 | || (class == tcc_binary |
1fe46df1 | 971 | && !(code == MODIFY_EXPR |
972 | || code == INIT_EXPR | |
973 | || code == PREDECREMENT_EXPR | |
974 | || code == PREINCREMENT_EXPR | |
975 | || code == POSTDECREMENT_EXPR | |
976 | || code == POSTINCREMENT_EXPR))) | |
ced7c954 | 977 | warning (OPT_Wunused_value, "value computed is not used"); |
1fe46df1 | 978 | } |
979 | } | |
00fa9079 | 980 | expr = build1 (CONVERT_EXPR, void_type_node, expr); |
b1a8d4ce | 981 | } |
de5ad4cb | 982 | if (! TREE_SIDE_EFFECTS (expr)) |
983 | expr = void_zero_node; | |
b1a8d4ce | 984 | return expr; |
985 | } | |
986 | ||
d81e00a4 | 987 | /* Create an expression whose value is that of EXPR, |
988 | converted to type TYPE. The TREE_TYPE of the value | |
989 | is always TYPE. This function implements all reasonable | |
990 | conversions; callers should filter out those that are | |
c4a8ac95 | 991 | not permitted by the language being compiled. |
992 | ||
993 | Most of this routine is from build_reinterpret_cast. | |
994 | ||
995 | The backend cannot call cp_convert (what was convert) because | |
996 | conversions to/from basetypes may involve memory references | |
997 | (vbases) and adding or subtracting small values (multiple | |
998 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 999 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 1000 | |
1001 | Also, if we ever support range variables, we'll probably also have to | |
1002 | do a little bit more work. */ | |
d81e00a4 | 1003 | |
1004 | tree | |
35771a9a | 1005 | convert (tree type, tree expr) |
d81e00a4 | 1006 | { |
c4a8ac95 | 1007 | tree intype; |
1008 | ||
1009 | if (type == error_mark_node || expr == error_mark_node) | |
1010 | return error_mark_node; | |
1011 | ||
c4a8ac95 | 1012 | intype = TREE_TYPE (expr); |
1013 | ||
6686e84d | 1014 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
13f0eb20 | 1015 | return fold_if_not_in_template (build_nop (type, expr)); |
c4a8ac95 | 1016 | |
1017 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
1018 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); | |
d81e00a4 | 1019 | } |
1020 | ||
c4a8ac95 | 1021 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 1022 | are not normally allowed due to access restrictions |
1023 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 1024 | |
471086d6 | 1025 | tree |
35771a9a | 1026 | convert_force (tree type, tree expr, int convtype) |
471086d6 | 1027 | { |
cd16867a | 1028 | tree e = expr; |
1029 | enum tree_code code = TREE_CODE (type); | |
471086d6 | 1030 | |
1031 | if (code == REFERENCE_TYPE) | |
9031d10b | 1032 | return (fold_if_not_in_template |
5d7ed6c7 | 1033 | (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, |
1034 | NULL_TREE))); | |
471086d6 | 1035 | |
1036 | if (code == POINTER_TYPE) | |
5d7ed6c7 | 1037 | return fold_if_not_in_template (convert_to_pointer_force (type, e)); |
471086d6 | 1038 | |
ac9386a0 | 1039 | /* From typeck.c convert_for_assignment */ |
471086d6 | 1040 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
1041 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
1042 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 1043 | || integer_zerop (e) |
1044 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 1045 | && TYPE_PTRMEMFUNC_P (type)) |
cb02169c | 1046 | /* compatible pointer to member functions. */ |
1047 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1, | |
1048 | /*c_cast_p=*/1); | |
a74e8896 | 1049 | |
c4a8ac95 | 1050 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
471086d6 | 1051 | } |
1052 | ||
471086d6 | 1053 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1054 | exists, return the attempted conversion. This may | |
1055 | return ERROR_MARK_NODE if the conversion is not | |
1056 | allowed (references private members, etc). | |
1057 | If no conversion exists, NULL_TREE is returned. | |
1058 | ||
ce28ee2e | 1059 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit |
1060 | object parameter, or by the second standard conversion sequence if | |
1061 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1062 | (jason 8/9/95) */ | |
471086d6 | 1063 | |
ef9571e5 | 1064 | static tree |
8999978b | 1065 | build_type_conversion (tree xtype, tree expr) |
471086d6 | 1066 | { |
1067 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1068 | into the required type. */ |
8999978b | 1069 | return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL); |
471086d6 | 1070 | } |
1071 | ||
1e66592c | 1072 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1073 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
35771a9a | 1074 | which indicates which types are suitable. If COMPLAIN is true, complain |
1e66592c | 1075 | about ambiguity; otherwise, the caller will deal with it. */ |
471086d6 | 1076 | |
1e66592c | 1077 | tree |
35771a9a | 1078 | build_expr_type_conversion (int desires, tree expr, bool complain) |
471086d6 | 1079 | { |
1e66592c | 1080 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1081 | tree conv = NULL_TREE; |
bdd152ce | 1082 | tree winner = NULL_TREE; |
471086d6 | 1083 | |
9031d10b | 1084 | if (expr == null_node |
1085 | && (desires & WANT_INT) | |
954885ed | 1086 | && !(desires & WANT_NULL)) |
308d6af4 | 1087 | warning (OPT_Wconversion, "converting NULL to non-pointer type"); |
9031d10b | 1088 | |
ce28ee2e | 1089 | basetype = TREE_TYPE (expr); |
471086d6 | 1090 | |
3d411d73 | 1091 | if (basetype == error_mark_node) |
1092 | return error_mark_node; | |
1093 | ||
bdd152ce | 1094 | if (! IS_AGGR_TYPE (basetype)) |
1095 | switch (TREE_CODE (basetype)) | |
1096 | { | |
1097 | case INTEGER_TYPE: | |
954885ed | 1098 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1099 | return expr; |
1100 | /* else fall through... */ | |
1101 | ||
955f5493 | 1102 | case VECTOR_TYPE: |
bdd152ce | 1103 | case BOOLEAN_TYPE: |
1104 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1105 | case ENUMERAL_TYPE: | |
1106 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1107 | case REAL_TYPE: | |
1108 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1109 | case POINTER_TYPE: | |
1110 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
9031d10b | 1111 | |
bdd152ce | 1112 | case FUNCTION_TYPE: |
1113 | case ARRAY_TYPE: | |
a681799d | 1114 | return (desires & WANT_POINTER) ? decay_conversion (expr) |
653e5405 | 1115 | : NULL_TREE; |
bdd152ce | 1116 | default: |
1117 | return NULL_TREE; | |
1118 | } | |
1119 | ||
1120 | /* The code for conversions from class type is currently only used for | |
1121 | delete expressions. Other expressions are handled by build_new_op. */ | |
f8182e08 | 1122 | if (!complete_type_or_else (basetype, expr)) |
1123 | return error_mark_node; | |
1124 | if (!TYPE_HAS_CONVERSION (basetype)) | |
bdd152ce | 1125 | return NULL_TREE; |
1126 | ||
1127 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) | |
1128 | { | |
1129 | int win = 0; | |
1130 | tree candidate; | |
1131 | tree cand = TREE_VALUE (conv); | |
1132 | ||
1133 | if (winner && winner == cand) | |
1134 | continue; | |
1135 | ||
ef4534a3 | 1136 | candidate = non_reference (TREE_TYPE (TREE_TYPE (cand))); |
bdd152ce | 1137 | |
1138 | switch (TREE_CODE (candidate)) | |
1139 | { | |
1140 | case BOOLEAN_TYPE: | |
1141 | case INTEGER_TYPE: | |
1142 | win = (desires & WANT_INT); break; | |
1143 | case ENUMERAL_TYPE: | |
1144 | win = (desires & WANT_ENUM); break; | |
1145 | case REAL_TYPE: | |
1146 | win = (desires & WANT_FLOAT); break; | |
1147 | case POINTER_TYPE: | |
1148 | win = (desires & WANT_POINTER); break; | |
1149 | ||
1150 | default: | |
1151 | break; | |
1152 | } | |
1153 | ||
1154 | if (win) | |
1155 | { | |
1156 | if (winner) | |
1157 | { | |
1158 | if (complain) | |
1159 | { | |
0a25aad6 | 1160 | error ("ambiguous default type conversion from %qT", |
653e5405 | 1161 | basetype); |
0a25aad6 | 1162 | error (" candidate conversions include %qD and %qD", |
653e5405 | 1163 | winner, cand); |
bdd152ce | 1164 | } |
1165 | return error_mark_node; | |
1166 | } | |
1167 | else | |
1168 | winner = cand; | |
1169 | } | |
1170 | } | |
1e66592c | 1171 | |
bdd152ce | 1172 | if (winner) |
1173 | { | |
ef4534a3 | 1174 | tree type = non_reference (TREE_TYPE (TREE_TYPE (winner))); |
bdd152ce | 1175 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL); |
471086d6 | 1176 | } |
1e66592c | 1177 | |
985e9ee0 | 1178 | return NULL_TREE; |
471086d6 | 1179 | } |
bc3887cf | 1180 | |
96624a9e | 1181 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1182 | ||
bc3887cf | 1183 | tree |
35771a9a | 1184 | type_promotes_to (tree type) |
bc3887cf | 1185 | { |
ce28ee2e | 1186 | if (type == error_mark_node) |
1187 | return error_mark_node; | |
1188 | ||
bc3887cf | 1189 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1190 | |
1191 | /* bool always promotes to int (not unsigned), even if it's the same | |
1192 | size. */ | |
028ea8b4 | 1193 | if (type == boolean_type_node) |
bb0726a1 | 1194 | type = integer_type_node; |
1195 | ||
1196 | /* Normally convert enums to int, but convert wide enums to something | |
1197 | wider. */ | |
1198 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
1199 | || type == wchar_type_node) | |
6c9497b1 | 1200 | { |
1201 | int precision = MAX (TYPE_PRECISION (type), | |
1202 | TYPE_PRECISION (integer_type_node)); | |
771d21fa | 1203 | tree totype = c_common_type_for_size (precision, 0); |
78a8ed03 | 1204 | if (TYPE_UNSIGNED (type) |
6c9497b1 | 1205 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) |
771d21fa | 1206 | type = c_common_type_for_size (precision, 1); |
6c9497b1 | 1207 | else |
1208 | type = totype; | |
1209 | } | |
d7aeef06 | 1210 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1211 | { |
d0acef9e | 1212 | /* Retain unsignedness if really not getting bigger. */ |
78a8ed03 | 1213 | if (TYPE_UNSIGNED (type) |
d0acef9e | 1214 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1215 | type = unsigned_type_node; |
1216 | else | |
1217 | type = integer_type_node; | |
1218 | } | |
1219 | else if (type == float_type_node) | |
1220 | type = double_type_node; | |
9031d10b | 1221 | |
a681799d | 1222 | return type; |
bc3887cf | 1223 | } |
668ae905 | 1224 | |
668ae905 | 1225 | /* The routines below this point are carefully written to conform to |
1226 | the standard. They use the same terminology, and follow the rules | |
1227 | closely. Although they are used only in pt.c at the moment, they | |
1228 | should presumably be used everywhere in the future. */ | |
1229 | ||
1146f179 | 1230 | /* Attempt to perform qualification conversions on EXPR to convert it |
1231 | to TYPE. Return the resulting expression, or error_mark_node if | |
1232 | the conversion was impossible. */ | |
1233 | ||
9031d10b | 1234 | tree |
35771a9a | 1235 | perform_qualification_conversions (tree type, tree expr) |
668ae905 | 1236 | { |
1bc16cab | 1237 | tree expr_type; |
1238 | ||
1239 | expr_type = TREE_TYPE (expr); | |
1240 | ||
3b087710 | 1241 | if (same_type_p (type, expr_type)) |
1242 | return expr; | |
1243 | else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type) | |
1244 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type))) | |
1bc16cab | 1245 | return build_nop (type, expr); |
1246 | else if (TYPE_PTR_TO_MEMBER_P (type) | |
1247 | && TYPE_PTR_TO_MEMBER_P (expr_type) | |
1248 | && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type), | |
1249 | TYPE_PTRMEM_CLASS_TYPE (expr_type)) | |
1250 | && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type), | |
1251 | TYPE_PTRMEM_POINTED_TO_TYPE (expr_type))) | |
1252 | return build_nop (type, expr); | |
1146f179 | 1253 | else |
1254 | return error_mark_node; | |
668ae905 | 1255 | } |