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8d08fdba | 1 | /* Language-level data type conversion for GNU C++. |
d6a8bdff | 2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, |
aa335b76 | 3 | 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. |
8d08fdba MS |
4 | Hacked by Michael Tiemann (tiemann@cygnus.com) |
5 | ||
f5adbb8d | 6 | This file is part of GCC. |
8d08fdba | 7 | |
f5adbb8d | 8 | GCC is free software; you can redistribute it and/or modify |
8d08fdba MS |
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 | ||
f5adbb8d | 13 | GCC is distributed in the hope that it will be useful, |
8d08fdba MS |
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 | |
f5adbb8d | 19 | along with GCC; see the file COPYING. If not, write to |
e9fa0c7c RK |
20 | the Free Software Foundation, 59 Temple Place - Suite 330, |
21 | Boston, MA 02111-1307, USA. */ | |
8d08fdba MS |
22 | |
23 | ||
3fd5abcf | 24 | /* This file contains the functions for converting C++ expressions |
8d08fdba MS |
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" | |
8d052bc7 | 30 | #include "system.h" |
4977bab6 ZW |
31 | #include "coretypes.h" |
32 | #include "tm.h" | |
8d08fdba MS |
33 | #include "tree.h" |
34 | #include "flags.h" | |
35 | #include "cp-tree.h" | |
8d08fdba | 36 | #include "convert.h" |
e833cb11 | 37 | #include "toplev.h" |
ddaed37e | 38 | #include "decl.h" |
e92cc029 | 39 | |
b746c5dc GDR |
40 | static tree cp_convert_to_pointer (tree, tree, bool); |
41 | static tree convert_to_pointer_force (tree, tree); | |
42 | static tree build_up_reference (tree, tree, int, tree); | |
43 | static void warn_ref_binding (tree, tree, tree); | |
49c249e1 | 44 | |
8d08fdba MS |
45 | /* Change of width--truncation and extension of integers or reals-- |
46 | is represented with NOP_EXPR. Proper functioning of many things | |
47 | assumes that no other conversions can be NOP_EXPRs. | |
48 | ||
49 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
50 | Converting integer to real uses FLOAT_EXPR | |
51 | and real to integer uses FIX_TRUNC_EXPR. | |
52 | ||
53 | Here is a list of all the functions that assume that widening and | |
54 | narrowing is always done with a NOP_EXPR: | |
55 | In convert.c, convert_to_integer. | |
56 | In c-typeck.c, build_binary_op_nodefault (boolean ops), | |
78ef5b89 | 57 | and c_common_truthvalue_conversion. |
8d08fdba MS |
58 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
59 | In fold-const.c: fold. | |
60 | In tree.c: get_narrower and get_unwidened. | |
61 | ||
62 | C++: in multiple-inheritance, converting between pointers may involve | |
63 | adjusting them by a delta stored within the class definition. */ | |
64 | \f | |
65 | /* Subroutines of `convert'. */ | |
66 | ||
8d08fdba MS |
67 | /* if converting pointer to pointer |
68 | if dealing with classes, check for derived->base or vice versa | |
69 | else if dealing with method pointers, delegate | |
70 | else convert blindly | |
71 | else if converting class, pass off to build_type_conversion | |
f9825168 NS |
72 | else try C-style pointer conversion. If FORCE is true then allow |
73 | conversions via virtual bases (these are permitted by reinterpret_cast, | |
74 | but not static_cast). */ | |
e92cc029 | 75 | |
8d08fdba | 76 | static tree |
b746c5dc | 77 | cp_convert_to_pointer (tree type, tree expr, bool force) |
8d08fdba | 78 | { |
926ce8bd KH |
79 | tree intype = TREE_TYPE (expr); |
80 | enum tree_code form; | |
31bcaa20 | 81 | tree rval; |
0c482362 AP |
82 | if (intype == error_mark_node) |
83 | return error_mark_node; | |
71851aaa | 84 | |
e92cc029 MS |
85 | if (IS_AGGR_TYPE (intype)) |
86 | { | |
e92cc029 | 87 | intype = complete_type (intype); |
d0f062fb | 88 | if (!COMPLETE_TYPE_P (intype)) |
e92cc029 | 89 | { |
939add70 GDR |
90 | error ("can't convert from incomplete type %qT to %qT", |
91 | intype, type); | |
e92cc029 MS |
92 | return error_mark_node; |
93 | } | |
94 | ||
7993382e | 95 | rval = build_type_conversion (type, expr); |
e92cc029 MS |
96 | if (rval) |
97 | { | |
98 | if (rval == error_mark_node) | |
939add70 GDR |
99 | error ("conversion of %qE from %qT to %qT is ambiguous", |
100 | expr, intype, type); | |
e92cc029 MS |
101 | return rval; |
102 | } | |
103 | } | |
104 | ||
faf5394a | 105 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
9a3b49ac MS |
106 | if (TREE_CODE (type) == POINTER_TYPE |
107 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
b72801e2 | 108 | || VOID_TYPE_P (TREE_TYPE (type)))) |
9a3b49ac | 109 | { |
33c25e5c MM |
110 | if (TYPE_PTRMEMFUNC_P (intype) |
111 | || TREE_CODE (intype) == METHOD_TYPE) | |
112 | return convert_member_func_to_ptr (type, expr); | |
d6b4ea85 MM |
113 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) |
114 | return build_nop (type, expr); | |
9a3b49ac MS |
115 | intype = TREE_TYPE (expr); |
116 | } | |
117 | ||
c87978aa JM |
118 | if (expr == error_mark_node) |
119 | return error_mark_node; | |
120 | ||
71851aaa MS |
121 | form = TREE_CODE (intype); |
122 | ||
d8f8dca1 | 123 | if (POINTER_TYPE_P (intype)) |
8d08fdba MS |
124 | { |
125 | intype = TYPE_MAIN_VARIANT (intype); | |
126 | ||
127 | if (TYPE_MAIN_VARIANT (type) != intype | |
d8f8dca1 | 128 | && TREE_CODE (type) == POINTER_TYPE |
8d08fdba | 129 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
a80e4195 MS |
130 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
131 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
338d90b8 | 132 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
8d08fdba MS |
133 | { |
134 | enum tree_code code = PLUS_EXPR; | |
338d90b8 | 135 | tree binfo; |
7993382e MM |
136 | tree intype_class; |
137 | tree type_class; | |
138 | bool same_p; | |
338d90b8 | 139 | |
7993382e MM |
140 | intype_class = TREE_TYPE (intype); |
141 | type_class = TREE_TYPE (type); | |
142 | ||
143 | same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class), | |
144 | TYPE_MAIN_VARIANT (type_class)); | |
145 | binfo = NULL_TREE; | |
00a17e31 | 146 | /* Try derived to base conversion. */ |
7993382e MM |
147 | if (!same_p) |
148 | binfo = lookup_base (intype_class, type_class, ba_check, NULL); | |
149 | if (!same_p && !binfo) | |
8d08fdba | 150 | { |
00a17e31 | 151 | /* Try base to derived conversion. */ |
7993382e | 152 | binfo = lookup_base (type_class, intype_class, ba_check, NULL); |
8d08fdba MS |
153 | code = MINUS_EXPR; |
154 | } | |
338d90b8 NS |
155 | if (binfo == error_mark_node) |
156 | return error_mark_node; | |
7993382e | 157 | if (binfo || same_p) |
8d08fdba | 158 | { |
7993382e MM |
159 | if (binfo) |
160 | expr = build_base_path (code, expr, binfo, 0); | |
00a17e31 | 161 | /* Add any qualifier conversions. */ |
7993382e | 162 | return build_nop (type, expr); |
8d08fdba MS |
163 | } |
164 | } | |
8d08fdba | 165 | |
a5ac359a | 166 | if (TYPE_PTRMEMFUNC_P (type)) |
28cbf42c | 167 | { |
939add70 GDR |
168 | error ("cannot convert %qE from type %qT to type %qT", |
169 | expr, intype, type); | |
a5ac359a MM |
170 | return error_mark_node; |
171 | } | |
b928a651 | 172 | |
a5ac359a MM |
173 | return build_nop (type, expr); |
174 | } | |
175 | else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) | |
176 | { | |
177 | tree b1; | |
178 | tree b2; | |
179 | tree binfo; | |
180 | enum tree_code code = PLUS_EXPR; | |
181 | base_kind bk; | |
182 | ||
183 | b1 = TYPE_PTRMEM_CLASS_TYPE (type); | |
184 | b2 = TYPE_PTRMEM_CLASS_TYPE (intype); | |
185 | binfo = lookup_base (b1, b2, ba_check, &bk); | |
186 | if (!binfo) | |
187 | { | |
188 | binfo = lookup_base (b2, b1, ba_check, &bk); | |
189 | code = MINUS_EXPR; | |
190 | } | |
191 | if (binfo == error_mark_node) | |
192 | return error_mark_node; | |
b928a651 | 193 | |
a5ac359a MM |
194 | if (bk == bk_via_virtual) |
195 | { | |
196 | if (force) | |
939add70 GDR |
197 | warning ("pointer to member cast from %qT to %qT is via" |
198 | " virtual base", intype, type); | |
a5ac359a | 199 | else |
6ad07332 | 200 | { |
939add70 GDR |
201 | error ("pointer to member cast from %qT to %qT is" |
202 | " via virtual base", intype, type); | |
a5ac359a | 203 | return error_mark_node; |
6ad07332 | 204 | } |
a5ac359a MM |
205 | /* This is a reinterpret cast, whose result is unspecified. |
206 | We choose to do nothing. */ | |
207 | return build1 (NOP_EXPR, type, expr); | |
f30432d7 MS |
208 | } |
209 | ||
a5ac359a MM |
210 | if (TREE_CODE (expr) == PTRMEM_CST) |
211 | expr = cplus_expand_constant (expr); | |
212 | ||
213 | if (binfo && !integer_zerop (BINFO_OFFSET (binfo))) | |
214 | expr = size_binop (code, | |
215 | build_nop (sizetype, expr), | |
216 | BINFO_OFFSET (binfo)); | |
7993382e | 217 | return build_nop (type, expr); |
8d08fdba | 218 | } |
d8f8dca1 | 219 | else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)) |
08e17d9d MM |
220 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
221 | /*c_cast_p=*/false); | |
d8f8dca1 MM |
222 | else if (TYPE_PTRMEMFUNC_P (intype)) |
223 | { | |
d6b4ea85 MM |
224 | if (!warn_pmf2ptr) |
225 | { | |
226 | if (TREE_CODE (expr) == PTRMEM_CST) | |
227 | return cp_convert_to_pointer (type, | |
228 | PTRMEM_CST_MEMBER (expr), | |
229 | force); | |
230 | else if (TREE_CODE (expr) == OFFSET_REF) | |
231 | { | |
232 | tree object = TREE_OPERAND (expr, 0); | |
233 | return get_member_function_from_ptrfunc (&object, | |
234 | TREE_OPERAND (expr, 1)); | |
235 | } | |
236 | } | |
939add70 GDR |
237 | error ("cannot convert %qE from type %qT to type %qT", |
238 | expr, intype, type); | |
d8f8dca1 MM |
239 | return error_mark_node; |
240 | } | |
8d08fdba | 241 | |
8d08fdba MS |
242 | if (integer_zerop (expr)) |
243 | { | |
d8f8dca1 | 244 | if (TYPE_PTRMEMFUNC_P (type)) |
08e17d9d MM |
245 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0, |
246 | /*c_cast_p=*/false); | |
cd8ed629 | 247 | |
1f84ec23 | 248 | if (TYPE_PTRMEM_P (type)) |
4a90aeeb NS |
249 | { |
250 | /* A NULL pointer-to-member is represented by -1, not by | |
251 | zero. */ | |
7d60be94 | 252 | expr = build_int_cst (type, -1); |
4a90aeeb NS |
253 | /* Fix up the representation of -1 if appropriate. */ |
254 | expr = force_fit_type (expr, 0, false, false); | |
255 | } | |
cd8ed629 | 256 | else |
7d60be94 | 257 | expr = build_int_cst (type, 0); |
ca7a3bd7 | 258 | |
8d08fdba MS |
259 | return expr; |
260 | } | |
a5ac359a | 261 | else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form)) |
201fbb7f | 262 | { |
939add70 | 263 | error ("invalid conversion from %qT to %qT", intype, type); |
201fbb7f GDR |
264 | return error_mark_node; |
265 | } | |
8d08fdba | 266 | |
2986ae00 | 267 | if (INTEGRAL_CODE_P (form)) |
8d08fdba | 268 | { |
f5963e61 | 269 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
8d08fdba | 270 | return build1 (CONVERT_EXPR, type, expr); |
b0c48229 | 271 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr); |
8dc2b103 NS |
272 | /* Modes may be different but sizes should be the same. There |
273 | is supposed to be some integral type that is the same width | |
274 | as a pointer. */ | |
275 | gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
276 | == GET_MODE_SIZE (TYPE_MODE (type))); | |
277 | ||
8d08fdba MS |
278 | return convert_to_pointer (type, expr); |
279 | } | |
280 | ||
e6e174e5 | 281 | if (type_unknown_p (expr)) |
c2ea3a40 | 282 | return instantiate_type (type, expr, tf_error | tf_warning); |
e6e174e5 | 283 | |
939add70 GDR |
284 | error ("cannot convert %qE from type %qT to type %qT", |
285 | expr, intype, type); | |
8d08fdba MS |
286 | return error_mark_node; |
287 | } | |
288 | ||
289 | /* Like convert, except permit conversions to take place which | |
290 | are not normally allowed due to access restrictions | |
291 | (such as conversion from sub-type to private super-type). */ | |
e92cc029 | 292 | |
8d08fdba | 293 | static tree |
b746c5dc | 294 | convert_to_pointer_force (tree type, tree expr) |
8d08fdba | 295 | { |
926ce8bd KH |
296 | tree intype = TREE_TYPE (expr); |
297 | enum tree_code form = TREE_CODE (intype); | |
8d08fdba | 298 | |
8d08fdba MS |
299 | if (form == POINTER_TYPE) |
300 | { | |
301 | intype = TYPE_MAIN_VARIANT (intype); | |
302 | ||
303 | if (TYPE_MAIN_VARIANT (type) != intype | |
304 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
a80e4195 MS |
305 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
306 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
8d08fdba MS |
307 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
308 | { | |
309 | enum tree_code code = PLUS_EXPR; | |
338d90b8 NS |
310 | tree binfo; |
311 | ||
312 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
18e4be85 | 313 | ba_unique, NULL); |
338d90b8 | 314 | if (!binfo) |
8d08fdba | 315 | { |
338d90b8 | 316 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
18e4be85 | 317 | ba_unique, NULL); |
338d90b8 | 318 | code = MINUS_EXPR; |
8d08fdba | 319 | } |
338d90b8 NS |
320 | if (binfo == error_mark_node) |
321 | return error_mark_node; | |
322 | if (binfo) | |
8d08fdba | 323 | { |
338d90b8 | 324 | expr = build_base_path (code, expr, binfo, 0); |
75c525d7 GDR |
325 | if (expr == error_mark_node) |
326 | return error_mark_node; | |
00a17e31 | 327 | /* Add any qualifier conversions. */ |
338d90b8 NS |
328 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), |
329 | TREE_TYPE (type))) | |
7993382e | 330 | expr = build_nop (type, expr); |
338d90b8 | 331 | return expr; |
8d08fdba | 332 | } |
8d08fdba | 333 | } |
8d08fdba MS |
334 | } |
335 | ||
b746c5dc | 336 | return cp_convert_to_pointer (type, expr, true); |
8d08fdba MS |
337 | } |
338 | ||
339 | /* We are passing something to a function which requires a reference. | |
340 | The type we are interested in is in TYPE. The initial | |
341 | value we have to begin with is in ARG. | |
342 | ||
343 | FLAGS controls how we manage access checking. | |
08ac397c JM |
344 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
345 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
e92cc029 | 346 | |
8d08fdba | 347 | static tree |
b746c5dc | 348 | build_up_reference (tree type, tree arg, int flags, tree decl) |
8d08fdba | 349 | { |
eb66be0e | 350 | tree rval; |
8926095f | 351 | tree argtype = TREE_TYPE (arg); |
8d08fdba | 352 | tree target_type = TREE_TYPE (type); |
8d08fdba | 353 | |
50bc768d | 354 | gcc_assert (TREE_CODE (type) == REFERENCE_TYPE); |
8d08fdba | 355 | |
eb66be0e | 356 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
8d08fdba | 357 | { |
08ac397c JM |
358 | /* Create a new temporary variable. We can't just use a TARGET_EXPR |
359 | here because it needs to live as long as DECL. */ | |
eb66be0e | 360 | tree targ = arg; |
08ac397c | 361 | |
aa6e8ed3 | 362 | arg = make_temporary_var_for_ref_to_temp (decl, TREE_TYPE (arg)); |
8d1e67c6 MM |
363 | |
364 | /* Process the initializer for the declaration. */ | |
9a3b49ac | 365 | DECL_INITIAL (arg) = targ; |
cd9f6678 | 366 | cp_finish_decl (arg, targ, NULL_TREE, |
c37dc68e | 367 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
e349ee73 | 368 | } |
eb66be0e | 369 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
c506ca22 | 370 | return get_target_expr (arg); |
e349ee73 | 371 | |
08ac397c | 372 | /* If we had a way to wrap this up, and say, if we ever needed its |
d2e5ee5c MS |
373 | address, transform all occurrences of the register, into a memory |
374 | reference we could win better. */ | |
eb66be0e | 375 | rval = build_unary_op (ADDR_EXPR, arg, 1); |
162bc98d JM |
376 | if (rval == error_mark_node) |
377 | return error_mark_node; | |
378 | ||
6633d636 MS |
379 | if ((flags & LOOKUP_PROTECT) |
380 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
381 | && IS_AGGR_TYPE (argtype) | |
382 | && IS_AGGR_TYPE (target_type)) | |
383 | { | |
2db1ab2d | 384 | /* We go through lookup_base for the access control. */ |
338d90b8 | 385 | tree binfo = lookup_base (argtype, target_type, ba_check, NULL); |
6633d636 MS |
386 | if (binfo == error_mark_node) |
387 | return error_mark_node; | |
388 | if (binfo == NULL_TREE) | |
389 | return error_not_base_type (target_type, argtype); | |
338d90b8 | 390 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1); |
6633d636 | 391 | } |
eb66be0e MS |
392 | else |
393 | rval | |
394 | = convert_to_pointer_force (build_pointer_type (target_type), rval); | |
7993382e | 395 | return build_nop (type, rval); |
8d08fdba MS |
396 | } |
397 | ||
08aead78 NS |
398 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
399 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
400 | for diagnostics. | |
401 | ||
402 | [dcl.init.ref] says that if an rvalue is used to | |
403 | initialize a reference, then the reference must be to a | |
404 | non-volatile const type. */ | |
405 | ||
406 | static void | |
b746c5dc | 407 | warn_ref_binding (tree reftype, tree intype, tree decl) |
08aead78 NS |
408 | { |
409 | tree ttl = TREE_TYPE (reftype); | |
410 | ||
411 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) | |
412 | { | |
413 | const char *msg; | |
414 | ||
415 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
939add70 GDR |
416 | msg = "initialization of volatile reference type %q#T from" |
417 | " rvalue of type %qT"; | |
08aead78 | 418 | else if (CP_TYPE_VOLATILE_P (ttl)) |
939add70 GDR |
419 | msg = "conversion to volatile reference type %q#T " |
420 | " from rvalue of type %qT"; | |
08aead78 | 421 | else if (decl) |
939add70 GDR |
422 | msg = "initialization of non-const reference type %q#T from" |
423 | " rvalue of type %qT"; | |
08aead78 | 424 | else |
939add70 GDR |
425 | msg = "conversion to non-const reference type %q#T from" |
426 | " rvalue of type %qT"; | |
08aead78 | 427 | |
33bd39a2 | 428 | pedwarn (msg, reftype, intype); |
08aead78 NS |
429 | } |
430 | } | |
431 | ||
8d08fdba MS |
432 | /* For C++: Only need to do one-level references, but cannot |
433 | get tripped up on signed/unsigned differences. | |
434 | ||
a4443a08 MS |
435 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
436 | initialized. It can be error_mark_node if we don't know the _DECL but | |
437 | we know it's an initialization. */ | |
8d08fdba | 438 | |
8d08fdba | 439 | tree |
b746c5dc GDR |
440 | convert_to_reference (tree reftype, tree expr, int convtype, |
441 | int flags, tree decl) | |
8d08fdba | 442 | { |
926ce8bd KH |
443 | tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); |
444 | tree intype; | |
8d08fdba | 445 | tree rval = NULL_TREE; |
8ccc31eb | 446 | tree rval_as_conversion = NULL_TREE; |
a5ac359a | 447 | bool can_convert_intype_to_type; |
8ccc31eb | 448 | |
2303a079 MM |
449 | if (TREE_CODE (type) == FUNCTION_TYPE |
450 | && TREE_TYPE (expr) == unknown_type_node) | |
a723baf1 MM |
451 | expr = instantiate_type (type, expr, |
452 | (flags & LOOKUP_COMPLAIN) | |
453 | ? tf_error | tf_warning : tf_none); | |
a723baf1 MM |
454 | |
455 | if (expr == error_mark_node) | |
456 | return error_mark_node; | |
457 | ||
458 | intype = TREE_TYPE (expr); | |
e6e174e5 | 459 | |
50bc768d | 460 | gcc_assert (TREE_CODE (intype) != REFERENCE_TYPE); |
8d08fdba | 461 | |
8d08fdba MS |
462 | intype = TYPE_MAIN_VARIANT (intype); |
463 | ||
a5ac359a MM |
464 | can_convert_intype_to_type = can_convert (type, intype); |
465 | if (!can_convert_intype_to_type | |
466 | && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) | |
8ccc31eb MS |
467 | && ! (flags & LOOKUP_NO_CONVERSION)) |
468 | { | |
469 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
470 | ||
277294d7 | 471 | rval_as_conversion |
7993382e | 472 | = build_type_conversion (reftype, expr); |
8ccc31eb MS |
473 | |
474 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
475 | && real_lvalue_p (rval_as_conversion)) | |
476 | { | |
477 | expr = rval_as_conversion; | |
478 | rval_as_conversion = NULL_TREE; | |
479 | intype = type; | |
a5ac359a | 480 | can_convert_intype_to_type = 1; |
8ccc31eb MS |
481 | } |
482 | } | |
483 | ||
a5ac359a MM |
484 | if (((convtype & CONV_STATIC) && can_convert (intype, type)) |
485 | || ((convtype & CONV_IMPLICIT) && can_convert_intype_to_type)) | |
8d08fdba | 486 | { |
8d08fdba MS |
487 | if (flags & LOOKUP_COMPLAIN) |
488 | { | |
39211cd5 | 489 | tree ttl = TREE_TYPE (reftype); |
8cd4c175 | 490 | tree ttr = lvalue_type (expr); |
8d08fdba | 491 | |
08aead78 NS |
492 | if (! real_lvalue_p (expr)) |
493 | warn_ref_binding (reftype, intype, decl); | |
494 | ||
495 | if (! (convtype & CONV_CONST) | |
91063b51 | 496 | && !at_least_as_qualified_p (ttl, ttr)) |
939add70 GDR |
497 | pedwarn ("conversion from %qT to %qT discards qualifiers", |
498 | ttr, reftype); | |
8926095f MS |
499 | } |
500 | ||
08ac397c | 501 | return build_up_reference (reftype, expr, flags, decl); |
8d08fdba | 502 | } |
21474714 | 503 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
8926095f MS |
504 | { |
505 | /* When casting an lvalue to a reference type, just convert into | |
506 | a pointer to the new type and deference it. This is allowed | |
a28e3c7f | 507 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
8926095f | 508 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
a28e3c7f | 509 | |
59be0cdd | 510 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
a28e3c7f | 511 | meant. */ |
8ccc31eb | 512 | if (TREE_CODE (intype) == POINTER_TYPE |
c8a209ca NS |
513 | && (comptypes (TREE_TYPE (intype), type, |
514 | COMPARE_BASE | COMPARE_DERIVED))) | |
939add70 | 515 | warning ("casting %qT to %qT does not dereference pointer", |
c8a209ca | 516 | intype, reftype); |
a28e3c7f | 517 | |
8926095f MS |
518 | rval = build_unary_op (ADDR_EXPR, expr, 0); |
519 | if (rval != error_mark_node) | |
3c215895 JM |
520 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
521 | rval, 0); | |
8926095f | 522 | if (rval != error_mark_node) |
7177d104 | 523 | rval = build1 (NOP_EXPR, reftype, rval); |
8926095f | 524 | } |
277294d7 | 525 | else |
faf5394a MS |
526 | { |
527 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
528 | "converting", 0, 0); | |
09ad2917 DD |
529 | if (rval == NULL_TREE || rval == error_mark_node) |
530 | return rval; | |
08aead78 | 531 | warn_ref_binding (reftype, intype, decl); |
08ac397c | 532 | rval = build_up_reference (reftype, rval, flags, decl); |
faf5394a | 533 | } |
8d08fdba MS |
534 | |
535 | if (rval) | |
536 | { | |
e92cc029 | 537 | /* If we found a way to convert earlier, then use it. */ |
8d08fdba MS |
538 | return rval; |
539 | } | |
540 | ||
878cd289 | 541 | if (flags & LOOKUP_COMPLAIN) |
939add70 | 542 | error ("cannot convert type %qT to type %qT", intype, reftype); |
878cd289 | 543 | |
8d08fdba MS |
544 | return error_mark_node; |
545 | } | |
546 | ||
547 | /* We are using a reference VAL for its value. Bash that reference all the | |
e92cc029 MS |
548 | way down to its lowest form. */ |
549 | ||
8d08fdba | 550 | tree |
b746c5dc | 551 | convert_from_reference (tree val) |
8d08fdba | 552 | { |
8d245821 | 553 | if (TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE) |
db24eb1f NS |
554 | { |
555 | tree t = canonical_type_variant (TREE_TYPE (TREE_TYPE (val))); | |
556 | tree ref = build1 (INDIRECT_REF, t, val); | |
557 | ||
558 | /* We *must* set TREE_READONLY when dereferencing a pointer to const, | |
559 | so that we get the proper error message if the result is used | |
560 | to assign to. Also, &* is supposed to be a no-op. */ | |
561 | TREE_READONLY (ref) = CP_TYPE_CONST_P (t); | |
562 | TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); | |
563 | TREE_SIDE_EFFECTS (ref) | |
564 | = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val)); | |
565 | REFERENCE_REF_P (ref) = 1; | |
566 | val = ref; | |
567 | } | |
568 | ||
8d08fdba MS |
569 | return val; |
570 | } | |
01f9e964 JM |
571 | |
572 | /* Implicitly convert the lvalue EXPR to another lvalue of type TOTYPE, | |
573 | preserving cv-qualification. */ | |
574 | ||
575 | tree | |
b746c5dc | 576 | convert_lvalue (tree totype, tree expr) |
01f9e964 JM |
577 | { |
578 | totype = cp_build_qualified_type (totype, TYPE_QUALS (TREE_TYPE (expr))); | |
579 | totype = build_reference_type (totype); | |
580 | expr = convert_to_reference (totype, expr, CONV_IMPLICIT, LOOKUP_NORMAL, | |
581 | NULL_TREE); | |
582 | return convert_from_reference (expr); | |
583 | } | |
f7b9026e JM |
584 | |
585 | /* Really perform an lvalue-to-rvalue conversion, including copying an | |
586 | argument of class type into a temporary. */ | |
587 | ||
588 | tree | |
589 | force_rvalue (tree expr) | |
590 | { | |
591 | if (IS_AGGR_TYPE (TREE_TYPE (expr)) && TREE_CODE (expr) != TARGET_EXPR) | |
592 | expr = ocp_convert (TREE_TYPE (expr), expr, | |
593 | CONV_IMPLICIT|CONV_FORCE_TEMP, LOOKUP_NORMAL); | |
594 | else | |
595 | expr = decay_conversion (expr); | |
596 | ||
597 | return expr; | |
598 | } | |
8d08fdba | 599 | \f |
37c46b43 MS |
600 | /* C++ conversions, preference to static cast conversions. */ |
601 | ||
602 | tree | |
b746c5dc | 603 | cp_convert (tree type, tree expr) |
37c46b43 MS |
604 | { |
605 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); | |
606 | } | |
607 | ||
878cd289 MS |
608 | /* Conversion... |
609 | ||
610 | FLAGS indicates how we should behave. */ | |
611 | ||
8d08fdba | 612 | tree |
b746c5dc | 613 | ocp_convert (tree type, tree expr, int convtype, int flags) |
8d08fdba | 614 | { |
926ce8bd KH |
615 | tree e = expr; |
616 | enum tree_code code = TREE_CODE (type); | |
8d08fdba | 617 | |
a5ac359a | 618 | if (error_operand_p (e) || type == error_mark_node) |
8d08fdba | 619 | return error_mark_node; |
a4443a08 | 620 | |
5d73aa63 MM |
621 | complete_type (type); |
622 | complete_type (TREE_TYPE (expr)); | |
623 | ||
fc611ce0 | 624 | e = decl_constant_value (e); |
9c0d0367 | 625 | |
dc26f471 JM |
626 | if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP) |
627 | /* Some internal structures (vtable_entry_type, sigtbl_ptr_type) | |
628 | don't go through finish_struct, so they don't have the synthesized | |
629 | constructors. So don't force a temporary. */ | |
630 | && TYPE_HAS_CONSTRUCTOR (type)) | |
8ccc31eb MS |
631 | /* We need a new temporary; don't take this shortcut. */; |
632 | else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) | |
01240200 | 633 | { |
3bfdc719 | 634 | if (same_type_p (type, TREE_TYPE (e))) |
01240200 MM |
635 | /* The call to fold will not always remove the NOP_EXPR as |
636 | might be expected, since if one of the types is a typedef; | |
34cd5ae7 | 637 | the comparison in fold is just equality of pointers, not a |
953360c8 MM |
638 | call to comptypes. We don't call fold in this case because |
639 | that can result in infinite recursion; fold will call | |
640 | convert, which will call ocp_convert, etc. */ | |
641 | return e; | |
a04678ca GDR |
642 | /* For complex data types, we need to perform componentwise |
643 | conversion. */ | |
644 | else if (TREE_CODE (type) == COMPLEX_TYPE) | |
455f19cb | 645 | return fold_if_not_in_template (convert_to_complex (type, e)); |
4e8dca1c JM |
646 | else if (TREE_CODE (e) == TARGET_EXPR) |
647 | { | |
648 | /* Don't build a NOP_EXPR of class type. Instead, change the | |
649 | type of the temporary. Only allow this for cv-qual changes, | |
650 | though. */ | |
8dc2b103 NS |
651 | gcc_assert (same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (e)), |
652 | TYPE_MAIN_VARIANT (type))); | |
4e8dca1c JM |
653 | TREE_TYPE (e) = TREE_TYPE (TARGET_EXPR_SLOT (e)) = type; |
654 | return e; | |
655 | } | |
01240200 | 656 | else |
8dc2b103 NS |
657 | { |
658 | /* We shouldn't be treating objects of ADDRESSABLE type as | |
659 | rvalues. */ | |
660 | gcc_assert (!TREE_ADDRESSABLE (type)); | |
455f19cb | 661 | return fold_if_not_in_template (build_nop (type, e)); |
8dc2b103 | 662 | } |
01240200 MM |
663 | } |
664 | ||
a4443a08 | 665 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
848b92e1 | 666 | { |
02cac427 | 667 | e = convert_to_void (e, /*implicit=*/NULL); |
66543169 | 668 | return e; |
848b92e1 | 669 | } |
a4443a08 | 670 | |
2986ae00 | 671 | if (INTEGRAL_CODE_P (code)) |
8d08fdba | 672 | { |
f0e01782 | 673 | tree intype = TREE_TYPE (e); |
824b9a4c MS |
674 | /* enum = enum, enum = int, enum = float, (enum)pointer are all |
675 | errors. */ | |
84663f74 | 676 | if (TREE_CODE (type) == ENUMERAL_TYPE |
b6ab6892 GB |
677 | && (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype) |
678 | || TREE_CODE (intype) == REAL_TYPE) | |
679 | && ! (convtype & CONV_STATIC)) | |
680 | || TREE_CODE (intype) == POINTER_TYPE)) | |
8d08fdba | 681 | { |
b6ab6892 GB |
682 | if (flags & LOOKUP_COMPLAIN) |
683 | pedwarn ("conversion from %q#T to %q#T", intype, type); | |
8d08fdba MS |
684 | |
685 | if (flag_pedantic_errors) | |
686 | return error_mark_node; | |
687 | } | |
a292b002 | 688 | if (IS_AGGR_TYPE (intype)) |
8d08fdba MS |
689 | { |
690 | tree rval; | |
7993382e | 691 | rval = build_type_conversion (type, e); |
00595019 MS |
692 | if (rval) |
693 | return rval; | |
878cd289 | 694 | if (flags & LOOKUP_COMPLAIN) |
939add70 | 695 | error ("%q#T used where a %qT was expected", intype, type); |
8d08fdba MS |
696 | return error_mark_node; |
697 | } | |
2986ae00 | 698 | if (code == BOOLEAN_TYPE) |
1998463c SB |
699 | return cp_truthvalue_conversion (e); |
700 | ||
455f19cb | 701 | return fold_if_not_in_template (convert_to_integer (type, e)); |
8d08fdba | 702 | } |
a5ac359a | 703 | if (POINTER_TYPE_P (type) || TYPE_PTR_TO_MEMBER_P (type)) |
455f19cb | 704 | return fold_if_not_in_template (cp_convert_to_pointer (type, e, false)); |
bb37c4a5 | 705 | if (code == VECTOR_TYPE) |
037cc9c5 FJ |
706 | { |
707 | tree in_vtype = TREE_TYPE (e); | |
708 | if (IS_AGGR_TYPE (in_vtype)) | |
709 | { | |
710 | tree ret_val; | |
711 | ret_val = build_type_conversion (type, e); | |
712 | if (ret_val) | |
713 | return ret_val; | |
714 | if (flags & LOOKUP_COMPLAIN) | |
939add70 | 715 | error ("%q#T used where a %qT was expected", in_vtype, type); |
037cc9c5 FJ |
716 | return error_mark_node; |
717 | } | |
455f19cb | 718 | return fold_if_not_in_template (convert_to_vector (type, e)); |
037cc9c5 | 719 | } |
37c46b43 | 720 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
8d08fdba MS |
721 | { |
722 | if (IS_AGGR_TYPE (TREE_TYPE (e))) | |
723 | { | |
724 | tree rval; | |
7993382e | 725 | rval = build_type_conversion (type, e); |
8d08fdba MS |
726 | if (rval) |
727 | return rval; | |
728 | else | |
878cd289 | 729 | if (flags & LOOKUP_COMPLAIN) |
939add70 | 730 | error ("%q#T used where a floating point value was expected", |
878cd289 | 731 | TREE_TYPE (e)); |
8d08fdba | 732 | } |
37c46b43 | 733 | if (code == REAL_TYPE) |
455f19cb | 734 | return fold_if_not_in_template (convert_to_real (type, e)); |
37c46b43 | 735 | else if (code == COMPLEX_TYPE) |
455f19cb | 736 | return fold_if_not_in_template (convert_to_complex (type, e)); |
8d08fdba MS |
737 | } |
738 | ||
739 | /* New C++ semantics: since assignment is now based on | |
740 | memberwise copying, if the rhs type is derived from the | |
741 | lhs type, then we may still do a conversion. */ | |
742 | if (IS_AGGR_TYPE_CODE (code)) | |
743 | { | |
744 | tree dtype = TREE_TYPE (e); | |
db5ae43f | 745 | tree ctor = NULL_TREE; |
8d08fdba | 746 | |
8d08fdba MS |
747 | dtype = TYPE_MAIN_VARIANT (dtype); |
748 | ||
8d08fdba MS |
749 | /* Conversion between aggregate types. New C++ semantics allow |
750 | objects of derived type to be cast to objects of base type. | |
751 | Old semantics only allowed this between pointers. | |
752 | ||
753 | There may be some ambiguity between using a constructor | |
754 | vs. using a type conversion operator when both apply. */ | |
755 | ||
277294d7 | 756 | ctor = e; |
faf5394a | 757 | |
a7a64a77 MM |
758 | if (abstract_virtuals_error (NULL_TREE, type)) |
759 | return error_mark_node; | |
59e76fc6 | 760 | |
277294d7 JM |
761 | if ((flags & LOOKUP_ONLYCONVERTING) |
762 | && ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype))) | |
62c154ed JM |
763 | /* For copy-initialization, first we create a temp of the proper type |
764 | with a user-defined conversion sequence, then we direct-initialize | |
765 | the target with the temp (see [dcl.init]). */ | |
766 | ctor = build_user_type_conversion (type, ctor, flags); | |
5e818b93 | 767 | else |
4ba126e4 MM |
768 | ctor = build_special_member_call (NULL_TREE, |
769 | complete_ctor_identifier, | |
770 | build_tree_list (NULL_TREE, ctor), | |
cad7e87b | 771 | type, flags); |
277294d7 JM |
772 | if (ctor) |
773 | return build_cplus_new (type, ctor); | |
8d08fdba MS |
774 | } |
775 | ||
878cd289 | 776 | if (flags & LOOKUP_COMPLAIN) |
939add70 GDR |
777 | error ("conversion from %qT to non-scalar type %qT requested", |
778 | TREE_TYPE (expr), type); | |
8d08fdba MS |
779 | return error_mark_node; |
780 | } | |
781 | ||
02cac427 NS |
782 | /* When an expression is used in a void context, its value is discarded and |
783 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
784 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
785 | in a void context. The C++ standard does not define what an `access' to an | |
cd0be382 | 786 | object is, but there is reason to believe that it is the lvalue to rvalue |
02cac427 NS |
787 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it |
788 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
789 | indicates that volatile semantics should be the same between C and C++ | |
790 | where ever possible. C leaves it implementation defined as to what | |
791 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
792 | the volatile object `vp' points to, unless that is an incomplete type. For | |
793 | volatile references we do not do this interpretation, because that would | |
794 | make it impossible to ignore the reference return value from functions. We | |
795 | issue warnings in the confusing cases. | |
796 | ||
797 | IMPLICIT is tells us the context of an implicit void conversion. */ | |
798 | ||
799 | tree | |
b746c5dc | 800 | convert_to_void (tree expr, const char *implicit) |
02cac427 | 801 | { |
07c88314 MM |
802 | if (expr == error_mark_node |
803 | || TREE_TYPE (expr) == error_mark_node) | |
804 | return error_mark_node; | |
02cac427 NS |
805 | if (!TREE_TYPE (expr)) |
806 | return expr; | |
c8b2e872 MM |
807 | if (invalid_nonstatic_memfn_p (expr)) |
808 | return error_mark_node; | |
b72801e2 | 809 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
02cac427 NS |
810 | return expr; |
811 | switch (TREE_CODE (expr)) | |
812 | { | |
813 | case COND_EXPR: | |
814 | { | |
815 | /* The two parts of a cond expr might be separate lvalues. */ | |
816 | tree op1 = TREE_OPERAND (expr,1); | |
817 | tree op2 = TREE_OPERAND (expr,2); | |
e895113a NS |
818 | tree new_op1 = convert_to_void |
819 | (op1, (implicit && !TREE_SIDE_EFFECTS (op2) | |
820 | ? "second operand of conditional" : NULL)); | |
821 | tree new_op2 = convert_to_void | |
822 | (op2, (implicit && !TREE_SIDE_EFFECTS (op1) | |
823 | ? "third operand of conditional" : NULL)); | |
02cac427 | 824 | |
f293ce4b RS |
825 | expr = build3 (COND_EXPR, TREE_TYPE (new_op1), |
826 | TREE_OPERAND (expr, 0), new_op1, new_op2); | |
02cac427 NS |
827 | break; |
828 | } | |
829 | ||
830 | case COMPOUND_EXPR: | |
831 | { | |
832 | /* The second part of a compound expr contains the value. */ | |
833 | tree op1 = TREE_OPERAND (expr,1); | |
e895113a | 834 | tree new_op1 = convert_to_void |
6de9cd9a | 835 | (op1, (implicit && !TREE_NO_WARNING (expr) |
f3da0ead | 836 | ? "right-hand operand of comma" : NULL)); |
02cac427 NS |
837 | |
838 | if (new_op1 != op1) | |
9a52d09b | 839 | { |
f293ce4b RS |
840 | tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1), |
841 | TREE_OPERAND (expr, 0), new_op1); | |
9a52d09b MM |
842 | expr = t; |
843 | } | |
844 | ||
02cac427 NS |
845 | break; |
846 | } | |
847 | ||
848 | case NON_LVALUE_EXPR: | |
849 | case NOP_EXPR: | |
00a17e31 | 850 | /* These have already decayed to rvalue. */ |
02cac427 NS |
851 | break; |
852 | ||
f4f206f4 | 853 | case CALL_EXPR: /* We have a special meaning for volatile void fn(). */ |
02cac427 NS |
854 | break; |
855 | ||
856 | case INDIRECT_REF: | |
857 | { | |
858 | tree type = TREE_TYPE (expr); | |
859 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
860 | == REFERENCE_TYPE; | |
861 | int is_volatile = TYPE_VOLATILE (type); | |
d0f062fb | 862 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
02cac427 NS |
863 | |
864 | if (is_volatile && !is_complete) | |
939add70 GDR |
865 | warning ("object of incomplete type %qT will not be accessed in %s", |
866 | type, implicit ? implicit : "void context"); | |
02cac427 | 867 | else if (is_reference && is_volatile) |
939add70 GDR |
868 | warning ("object of type %qT will not be accessed in %s", |
869 | TREE_TYPE (TREE_OPERAND (expr, 0)), | |
870 | implicit ? implicit : "void context"); | |
02cac427 NS |
871 | if (is_reference || !is_volatile || !is_complete) |
872 | expr = TREE_OPERAND (expr, 0); | |
873 | ||
874 | break; | |
875 | } | |
876 | ||
877 | case VAR_DECL: | |
878 | { | |
879 | /* External variables might be incomplete. */ | |
880 | tree type = TREE_TYPE (expr); | |
d0f062fb | 881 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
02cac427 NS |
882 | |
883 | if (TYPE_VOLATILE (type) && !is_complete) | |
939add70 GDR |
884 | warning ("object %qE of incomplete type %qT will not be accessed in %s", |
885 | expr, type, implicit ? implicit : "void context"); | |
02cac427 NS |
886 | break; |
887 | } | |
2bdb0643 | 888 | |
02cac427 NS |
889 | default:; |
890 | } | |
891 | { | |
892 | tree probe = expr; | |
893 | ||
894 | if (TREE_CODE (probe) == ADDR_EXPR) | |
895 | probe = TREE_OPERAND (expr, 0); | |
96d6c610 JM |
896 | if (type_unknown_p (probe)) |
897 | { | |
898 | /* [over.over] enumerates the places where we can take the address | |
899 | of an overloaded function, and this is not one of them. */ | |
33bd39a2 | 900 | pedwarn ("%s cannot resolve address of overloaded function", |
96d6c610 | 901 | implicit ? implicit : "void cast"); |
394b9d99 | 902 | expr = void_zero_node; |
96d6c610 JM |
903 | } |
904 | else if (implicit && probe == expr && is_overloaded_fn (probe)) | |
02cac427 | 905 | /* Only warn when there is no &. */ |
939add70 | 906 | warning ("%s is a reference, not call, to function %qE", |
96d6c610 | 907 | implicit, expr); |
02cac427 NS |
908 | } |
909 | ||
b72801e2 | 910 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
02cac427 | 911 | { |
6de9cd9a DN |
912 | if (implicit && warn_unused_value |
913 | && !TREE_SIDE_EFFECTS (expr) && !TREE_NO_WARNING (expr)) | |
e895113a NS |
914 | warning ("%s has no effect", implicit); |
915 | expr = build1 (CONVERT_EXPR, void_type_node, expr); | |
02cac427 NS |
916 | } |
917 | return expr; | |
918 | } | |
919 | ||
a4443a08 MS |
920 | /* Create an expression whose value is that of EXPR, |
921 | converted to type TYPE. The TREE_TYPE of the value | |
922 | is always TYPE. This function implements all reasonable | |
923 | conversions; callers should filter out those that are | |
37c46b43 MS |
924 | not permitted by the language being compiled. |
925 | ||
926 | Most of this routine is from build_reinterpret_cast. | |
927 | ||
928 | The backend cannot call cp_convert (what was convert) because | |
929 | conversions to/from basetypes may involve memory references | |
930 | (vbases) and adding or subtracting small values (multiple | |
931 | inheritance), but it calls convert from the constant folding code | |
7dfa399d | 932 | on subtrees of already built trees after it has ripped them apart. |
37c46b43 MS |
933 | |
934 | Also, if we ever support range variables, we'll probably also have to | |
935 | do a little bit more work. */ | |
a4443a08 MS |
936 | |
937 | tree | |
b746c5dc | 938 | convert (tree type, tree expr) |
a4443a08 | 939 | { |
37c46b43 MS |
940 | tree intype; |
941 | ||
942 | if (type == error_mark_node || expr == error_mark_node) | |
943 | return error_mark_node; | |
944 | ||
37c46b43 MS |
945 | intype = TREE_TYPE (expr); |
946 | ||
6633d636 | 947 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
37c46b43 | 948 | { |
fc611ce0 | 949 | expr = decl_constant_value (expr); |
455f19cb | 950 | return fold_if_not_in_template (build_nop (type, expr)); |
37c46b43 MS |
951 | } |
952 | ||
953 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
954 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); | |
a4443a08 MS |
955 | } |
956 | ||
37c46b43 | 957 | /* Like cp_convert, except permit conversions to take place which |
8d08fdba MS |
958 | are not normally allowed due to access restrictions |
959 | (such as conversion from sub-type to private super-type). */ | |
e92cc029 | 960 | |
8d08fdba | 961 | tree |
b746c5dc | 962 | convert_force (tree type, tree expr, int convtype) |
8d08fdba | 963 | { |
926ce8bd KH |
964 | tree e = expr; |
965 | enum tree_code code = TREE_CODE (type); | |
8d08fdba MS |
966 | |
967 | if (code == REFERENCE_TYPE) | |
455f19cb MM |
968 | return (fold_if_not_in_template |
969 | (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, | |
970 | NULL_TREE))); | |
8d08fdba MS |
971 | |
972 | if (code == POINTER_TYPE) | |
455f19cb | 973 | return fold_if_not_in_template (convert_to_pointer_force (type, e)); |
8d08fdba | 974 | |
51c184be | 975 | /* From typeck.c convert_for_assignment */ |
8d08fdba MS |
976 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
977 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
978 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
51c184be MS |
979 | || integer_zerop (e) |
980 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
8d08fdba | 981 | && TYPE_PTRMEMFUNC_P (type)) |
08e17d9d MM |
982 | /* compatible pointer to member functions. */ |
983 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1, | |
984 | /*c_cast_p=*/1); | |
6060a796 | 985 | |
37c46b43 | 986 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
8d08fdba MS |
987 | } |
988 | ||
8d08fdba MS |
989 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
990 | exists, return the attempted conversion. This may | |
991 | return ERROR_MARK_NODE if the conversion is not | |
992 | allowed (references private members, etc). | |
993 | If no conversion exists, NULL_TREE is returned. | |
994 | ||
f30432d7 MS |
995 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit |
996 | object parameter, or by the second standard conversion sequence if | |
997 | that doesn't do it. This will probably wait for an overloading rewrite. | |
998 | (jason 8/9/95) */ | |
8d08fdba | 999 | |
8d08fdba | 1000 | tree |
7993382e | 1001 | build_type_conversion (tree xtype, tree expr) |
8d08fdba MS |
1002 | { |
1003 | /* C++: check to see if we can convert this aggregate type | |
e1cd6e56 | 1004 | into the required type. */ |
7993382e | 1005 | return build_user_type_conversion (xtype, expr, LOOKUP_NORMAL); |
8d08fdba MS |
1006 | } |
1007 | ||
b7484fbe MS |
1008 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1009 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
b746c5dc | 1010 | which indicates which types are suitable. If COMPLAIN is true, complain |
b7484fbe | 1011 | about ambiguity; otherwise, the caller will deal with it. */ |
8d08fdba | 1012 | |
b7484fbe | 1013 | tree |
b746c5dc | 1014 | build_expr_type_conversion (int desires, tree expr, bool complain) |
8d08fdba | 1015 | { |
b7484fbe | 1016 | tree basetype = TREE_TYPE (expr); |
b370501f | 1017 | tree conv = NULL_TREE; |
02020185 | 1018 | tree winner = NULL_TREE; |
8d08fdba | 1019 | |
03d0f4af MM |
1020 | if (expr == null_node |
1021 | && (desires & WANT_INT) | |
1022 | && !(desires & WANT_NULL)) | |
33bd39a2 | 1023 | warning ("converting NULL to non-pointer type"); |
03d0f4af | 1024 | |
f30432d7 | 1025 | basetype = TREE_TYPE (expr); |
8d08fdba | 1026 | |
07c88314 MM |
1027 | if (basetype == error_mark_node) |
1028 | return error_mark_node; | |
1029 | ||
02020185 JM |
1030 | if (! IS_AGGR_TYPE (basetype)) |
1031 | switch (TREE_CODE (basetype)) | |
1032 | { | |
1033 | case INTEGER_TYPE: | |
03d0f4af | 1034 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
02020185 JM |
1035 | return expr; |
1036 | /* else fall through... */ | |
1037 | ||
1038 | case BOOLEAN_TYPE: | |
1039 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1040 | case ENUMERAL_TYPE: | |
1041 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1042 | case REAL_TYPE: | |
1043 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1044 | case POINTER_TYPE: | |
1045 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
3c215895 | 1046 | |
02020185 JM |
1047 | case FUNCTION_TYPE: |
1048 | case ARRAY_TYPE: | |
0a72704b | 1049 | return (desires & WANT_POINTER) ? decay_conversion (expr) |
02020185 JM |
1050 | : NULL_TREE; |
1051 | default: | |
1052 | return NULL_TREE; | |
1053 | } | |
1054 | ||
1055 | /* The code for conversions from class type is currently only used for | |
1056 | delete expressions. Other expressions are handled by build_new_op. */ | |
29f4ceab GB |
1057 | if (!complete_type_or_else (basetype, expr)) |
1058 | return error_mark_node; | |
1059 | if (!TYPE_HAS_CONVERSION (basetype)) | |
02020185 JM |
1060 | return NULL_TREE; |
1061 | ||
1062 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) | |
1063 | { | |
1064 | int win = 0; | |
1065 | tree candidate; | |
1066 | tree cand = TREE_VALUE (conv); | |
1067 | ||
1068 | if (winner && winner == cand) | |
1069 | continue; | |
1070 | ||
ee76b931 | 1071 | candidate = non_reference (TREE_TYPE (TREE_TYPE (cand))); |
02020185 JM |
1072 | |
1073 | switch (TREE_CODE (candidate)) | |
1074 | { | |
1075 | case BOOLEAN_TYPE: | |
1076 | case INTEGER_TYPE: | |
1077 | win = (desires & WANT_INT); break; | |
1078 | case ENUMERAL_TYPE: | |
1079 | win = (desires & WANT_ENUM); break; | |
1080 | case REAL_TYPE: | |
1081 | win = (desires & WANT_FLOAT); break; | |
1082 | case POINTER_TYPE: | |
1083 | win = (desires & WANT_POINTER); break; | |
1084 | ||
1085 | default: | |
1086 | break; | |
1087 | } | |
1088 | ||
1089 | if (win) | |
1090 | { | |
1091 | if (winner) | |
1092 | { | |
1093 | if (complain) | |
1094 | { | |
939add70 GDR |
1095 | error ("ambiguous default type conversion from %qT", |
1096 | basetype); | |
1097 | error (" candidate conversions include %qD and %qD", | |
1098 | winner, cand); | |
02020185 JM |
1099 | } |
1100 | return error_mark_node; | |
1101 | } | |
1102 | else | |
1103 | winner = cand; | |
1104 | } | |
1105 | } | |
b7484fbe | 1106 | |
02020185 JM |
1107 | if (winner) |
1108 | { | |
ee76b931 | 1109 | tree type = non_reference (TREE_TYPE (TREE_TYPE (winner))); |
02020185 | 1110 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL); |
8d08fdba | 1111 | } |
b7484fbe | 1112 | |
3c215895 | 1113 | return NULL_TREE; |
8d08fdba | 1114 | } |
39211cd5 | 1115 | |
e92cc029 MS |
1116 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1117 | ||
39211cd5 | 1118 | tree |
b746c5dc | 1119 | type_promotes_to (tree type) |
39211cd5 | 1120 | { |
f30432d7 MS |
1121 | if (type == error_mark_node) |
1122 | return error_mark_node; | |
1123 | ||
39211cd5 | 1124 | type = TYPE_MAIN_VARIANT (type); |
2986ae00 MS |
1125 | |
1126 | /* bool always promotes to int (not unsigned), even if it's the same | |
1127 | size. */ | |
28ed4616 | 1128 | if (type == boolean_type_node) |
2986ae00 MS |
1129 | type = integer_type_node; |
1130 | ||
1131 | /* Normally convert enums to int, but convert wide enums to something | |
1132 | wider. */ | |
1133 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
1134 | || type == wchar_type_node) | |
cf2ac46f JM |
1135 | { |
1136 | int precision = MAX (TYPE_PRECISION (type), | |
1137 | TYPE_PRECISION (integer_type_node)); | |
b0c48229 | 1138 | tree totype = c_common_type_for_size (precision, 0); |
8df83eae | 1139 | if (TYPE_UNSIGNED (type) |
cf2ac46f | 1140 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) |
b0c48229 | 1141 | type = c_common_type_for_size (precision, 1); |
cf2ac46f JM |
1142 | else |
1143 | type = totype; | |
1144 | } | |
d72040f5 | 1145 | else if (c_promoting_integer_type_p (type)) |
39211cd5 | 1146 | { |
3d4683cb | 1147 | /* Retain unsignedness if really not getting bigger. */ |
8df83eae | 1148 | if (TYPE_UNSIGNED (type) |
3d4683cb | 1149 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
39211cd5 MS |
1150 | type = unsigned_type_node; |
1151 | else | |
1152 | type = integer_type_node; | |
1153 | } | |
1154 | else if (type == float_type_node) | |
1155 | type = double_type_node; | |
0a72704b MM |
1156 | |
1157 | return type; | |
39211cd5 | 1158 | } |
75650646 | 1159 | |
75650646 MM |
1160 | /* The routines below this point are carefully written to conform to |
1161 | the standard. They use the same terminology, and follow the rules | |
1162 | closely. Although they are used only in pt.c at the moment, they | |
1163 | should presumably be used everywhere in the future. */ | |
1164 | ||
e1467ff2 MM |
1165 | /* Attempt to perform qualification conversions on EXPR to convert it |
1166 | to TYPE. Return the resulting expression, or error_mark_node if | |
1167 | the conversion was impossible. */ | |
1168 | ||
75650646 | 1169 | tree |
b746c5dc | 1170 | perform_qualification_conversions (tree type, tree expr) |
75650646 | 1171 | { |
a5ac359a MM |
1172 | tree expr_type; |
1173 | ||
1174 | expr_type = TREE_TYPE (expr); | |
1175 | ||
1176 | if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type) | |
1177 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type))) | |
1178 | return build_nop (type, expr); | |
1179 | else if (TYPE_PTR_TO_MEMBER_P (type) | |
1180 | && TYPE_PTR_TO_MEMBER_P (expr_type) | |
1181 | && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type), | |
1182 | TYPE_PTRMEM_CLASS_TYPE (expr_type)) | |
1183 | && comp_ptr_ttypes (TYPE_PTRMEM_POINTED_TO_TYPE (type), | |
1184 | TYPE_PTRMEM_POINTED_TO_TYPE (expr_type))) | |
1185 | return build_nop (type, expr); | |
e1467ff2 MM |
1186 | else |
1187 | return error_mark_node; | |
75650646 | 1188 | } |