]>
Commit | Line | Data |
---|---|---|
471086d6 | 1 | /* Language-level data type conversion for GNU C++. |
107c7f39 | 2 | Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, |
e63bd8ae | 3 | 1999, 2000, 2001, 2002 Free Software Foundation, Inc. |
471086d6 | 4 | Hacked by Michael Tiemann (tiemann@cygnus.com) |
5 | ||
6 | This file is part of GNU CC. | |
7 | ||
8 | GNU CC is free software; you can redistribute it and/or modify | |
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 | ||
13 | GNU CC is distributed in the hope that it will be useful, | |
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 | |
19 | along with GNU CC; see the file COPYING. If not, write to | |
c58d4270 | 20 | the Free Software Foundation, 59 Temple Place - Suite 330, |
21 | Boston, MA 02111-1307, USA. */ | |
471086d6 | 22 | |
23 | ||
24 | /* This file contains the functions for converting C expressions | |
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" |
471086d6 | 31 | #include "tree.h" |
32 | #include "flags.h" | |
33 | #include "cp-tree.h" | |
471086d6 | 34 | #include "convert.h" |
f0eaeecd | 35 | #include "toplev.h" |
2e8226f7 | 36 | #include "decl.h" |
96624a9e | 37 | |
045ed8f8 | 38 | static tree cp_convert_to_pointer PARAMS ((tree, tree, int)); |
24054144 | 39 | static tree convert_to_pointer_force PARAMS ((tree, tree)); |
ca106ab1 | 40 | static tree build_up_reference PARAMS ((tree, tree, int, tree)); |
519ba62c | 41 | static void warn_ref_binding PARAMS ((tree, tree, tree)); |
71ccdfff | 42 | |
471086d6 | 43 | /* Change of width--truncation and extension of integers or reals-- |
44 | is represented with NOP_EXPR. Proper functioning of many things | |
45 | assumes that no other conversions can be NOP_EXPRs. | |
46 | ||
47 | Conversion between integer and pointer is represented with CONVERT_EXPR. | |
48 | Converting integer to real uses FLOAT_EXPR | |
49 | and real to integer uses FIX_TRUNC_EXPR. | |
50 | ||
51 | Here is a list of all the functions that assume that widening and | |
52 | narrowing is always done with a NOP_EXPR: | |
53 | In convert.c, convert_to_integer. | |
54 | In c-typeck.c, build_binary_op_nodefault (boolean ops), | |
aff9e656 | 55 | and c_common_truthvalue_conversion. |
471086d6 | 56 | In expr.c: expand_expr, for operands of a MULT_EXPR. |
57 | In fold-const.c: fold. | |
58 | In tree.c: get_narrower and get_unwidened. | |
59 | ||
60 | C++: in multiple-inheritance, converting between pointers may involve | |
61 | adjusting them by a delta stored within the class definition. */ | |
62 | \f | |
63 | /* Subroutines of `convert'. */ | |
64 | ||
471086d6 | 65 | /* if converting pointer to pointer |
66 | if dealing with classes, check for derived->base or vice versa | |
67 | else if dealing with method pointers, delegate | |
68 | else convert blindly | |
69 | else if converting class, pass off to build_type_conversion | |
045ed8f8 | 70 | else try C-style pointer conversion. If FORCE is true then allow |
71 | conversions via virtual bases (these are permitted by reinterpret_cast, | |
72 | but not static_cast). */ | |
96624a9e | 73 | |
471086d6 | 74 | static tree |
045ed8f8 | 75 | cp_convert_to_pointer (type, expr, force) |
471086d6 | 76 | tree type, expr; |
045ed8f8 | 77 | int force; |
471086d6 | 78 | { |
79 | register tree intype = TREE_TYPE (expr); | |
74002e1d | 80 | register enum tree_code form; |
f82eeb87 | 81 | tree rval; |
74002e1d | 82 | |
96624a9e | 83 | if (IS_AGGR_TYPE (intype)) |
84 | { | |
96624a9e | 85 | intype = complete_type (intype); |
4b72716d | 86 | if (!COMPLETE_TYPE_P (intype)) |
96624a9e | 87 | { |
cf103c6c | 88 | error ("can't convert from incomplete type `%T' to `%T'", |
96624a9e | 89 | intype, type); |
90 | return error_mark_node; | |
91 | } | |
92 | ||
1c16607c | 93 | rval = build_type_conversion (type, expr, 1); |
96624a9e | 94 | if (rval) |
95 | { | |
96 | if (rval == error_mark_node) | |
cf103c6c | 97 | error ("conversion of `%E' from `%T' to `%T' is ambiguous", |
96624a9e | 98 | expr, intype, type); |
99 | return rval; | |
100 | } | |
101 | } | |
102 | ||
860740a7 | 103 | /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
38281c46 | 104 | if (TREE_CODE (type) == POINTER_TYPE |
105 | && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE | |
e3cfe3ce | 106 | || VOID_TYPE_P (TREE_TYPE (type)))) |
38281c46 | 107 | { |
108 | /* Allow an implicit this pointer for pointer to member | |
109 | functions. */ | |
860740a7 | 110 | if (TYPE_PTRMEMFUNC_P (intype)) |
38281c46 | 111 | { |
860740a7 | 112 | tree fntype = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (intype)); |
2917b86f | 113 | tree decl = maybe_dummy_object (TYPE_METHOD_BASETYPE (fntype), 0); |
38281c46 | 114 | expr = build (OFFSET_REF, fntype, decl, expr); |
115 | } | |
116 | ||
117 | if (TREE_CODE (expr) == OFFSET_REF | |
118 | && TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
119 | expr = resolve_offset_ref (expr); | |
120 | if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) | |
121 | expr = build_addr_func (expr); | |
122 | if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) | |
123 | { | |
124 | if (TREE_CODE (TREE_TYPE (TREE_TYPE (expr))) == METHOD_TYPE) | |
125 | if (pedantic || warn_pmf2ptr) | |
cf103c6c | 126 | pedwarn ("converting from `%T' to `%T'", TREE_TYPE (expr), |
38281c46 | 127 | type); |
128 | return build1 (NOP_EXPR, type, expr); | |
129 | } | |
130 | intype = TREE_TYPE (expr); | |
131 | } | |
132 | ||
311e42bc | 133 | if (expr == error_mark_node) |
134 | return error_mark_node; | |
135 | ||
74002e1d | 136 | form = TREE_CODE (intype); |
137 | ||
2b77484d | 138 | if (POINTER_TYPE_P (intype)) |
471086d6 | 139 | { |
140 | intype = TYPE_MAIN_VARIANT (intype); | |
141 | ||
142 | if (TYPE_MAIN_VARIANT (type) != intype | |
2b77484d | 143 | && TREE_CODE (type) == POINTER_TYPE |
471086d6 | 144 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
bccffb3a | 145 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
146 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
4a2680fc | 147 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
471086d6 | 148 | { |
149 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 150 | tree binfo; |
151 | ||
152 | /* Try derived to base conversion. */ | |
153 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
154 | ba_check, NULL); | |
155 | if (!binfo) | |
471086d6 | 156 | { |
4a2680fc | 157 | /* Try base to derived conversion. */ |
158 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), | |
159 | ba_check, NULL); | |
471086d6 | 160 | code = MINUS_EXPR; |
161 | } | |
4a2680fc | 162 | if (binfo == error_mark_node) |
163 | return error_mark_node; | |
471086d6 | 164 | if (binfo) |
165 | { | |
4a2680fc | 166 | expr = build_base_path (code, expr, binfo, 0); |
167 | /* Add any qualifier conversions. */ | |
168 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), | |
169 | TREE_TYPE (type))) | |
471086d6 | 170 | { |
4a2680fc | 171 | expr = build1 (NOP_EXPR, type, expr); |
172 | TREE_CONSTANT (expr) = | |
173 | TREE_CONSTANT (TREE_OPERAND (expr, 0)); | |
471086d6 | 174 | } |
4a2680fc | 175 | return expr; |
471086d6 | 176 | } |
177 | } | |
471086d6 | 178 | |
1c16607c | 179 | if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) |
bea7d742 | 180 | { |
a17aefa2 | 181 | tree b1; |
182 | tree b2; | |
183 | tree binfo; | |
4a2680fc | 184 | enum tree_code code = PLUS_EXPR; |
185 | base_kind bk; | |
a17aefa2 | 186 | |
187 | b1 = TYPE_OFFSET_BASETYPE (TREE_TYPE (type)); | |
188 | b2 = TYPE_OFFSET_BASETYPE (TREE_TYPE (intype)); | |
4a2680fc | 189 | binfo = lookup_base (b1, b2, ba_check, &bk); |
190 | if (!binfo) | |
fc9fc8d8 | 191 | { |
4a2680fc | 192 | binfo = lookup_base (b2, b1, ba_check, &bk); |
fc9fc8d8 | 193 | code = MINUS_EXPR; |
194 | } | |
bea7d742 | 195 | if (binfo == error_mark_node) |
196 | return error_mark_node; | |
a17aefa2 | 197 | |
4a2680fc | 198 | if (bk == bk_via_virtual) |
7045d67a | 199 | { |
045ed8f8 | 200 | if (force) |
cf103c6c | 201 | warning ("pointer to member cast from `%T' to `%T' is via virtual base", |
4a2680fc | 202 | TREE_TYPE (intype), TREE_TYPE (type)); |
045ed8f8 | 203 | else |
204 | { | |
cf103c6c | 205 | error ("pointer to member cast from `%T' to `%T' is via virtual base", |
4a2680fc | 206 | TREE_TYPE (intype), TREE_TYPE (type)); |
045ed8f8 | 207 | return error_mark_node; |
208 | } | |
1bbb5947 | 209 | /* This is a reinterpret cast, whose result is unspecified. |
210 | We choose to do nothing. */ | |
211 | return build1 (NOP_EXPR, type, expr); | |
7045d67a | 212 | } |
213 | ||
a17aefa2 | 214 | if (TREE_CODE (expr) == PTRMEM_CST) |
215 | expr = cplus_expand_constant (expr); | |
216 | ||
1bbb5947 | 217 | if (binfo) |
218 | expr = size_binop (code, convert (sizetype, expr), | |
902de8ed | 219 | BINFO_OFFSET (binfo)); |
bea7d742 | 220 | } |
2b77484d | 221 | else if (TYPE_PTRMEMFUNC_P (type)) |
ce28ee2e | 222 | { |
cf103c6c | 223 | error ("cannot convert `%E' from type `%T' to type `%T'", |
ce28ee2e | 224 | expr, intype, type); |
225 | return error_mark_node; | |
226 | } | |
227 | ||
f82eeb87 | 228 | rval = build1 (NOP_EXPR, type, expr); |
229 | TREE_CONSTANT (rval) = TREE_CONSTANT (expr); | |
230 | return rval; | |
471086d6 | 231 | } |
2b77484d | 232 | else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)) |
7045d67a | 233 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
2b77484d | 234 | else if (TYPE_PTRMEMFUNC_P (intype)) |
235 | { | |
cf103c6c | 236 | error ("cannot convert `%E' from type `%T' to type `%T'", |
2b77484d | 237 | expr, intype, type); |
238 | return error_mark_node; | |
239 | } | |
471086d6 | 240 | |
241 | my_friendly_assert (form != OFFSET_TYPE, 186); | |
242 | ||
471086d6 | 243 | if (integer_zerop (expr)) |
244 | { | |
2b77484d | 245 | if (TYPE_PTRMEMFUNC_P (type)) |
f05d5d03 | 246 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0); |
ad63a0fc | 247 | |
606b494c | 248 | if (TYPE_PTRMEM_P (type)) |
5ad590ad | 249 | /* A NULL pointer-to-member is represented by -1, not by |
250 | zero. */ | |
ad63a0fc | 251 | expr = build_int_2 (-1, -1); |
252 | else | |
253 | expr = build_int_2 (0, 0); | |
471086d6 | 254 | TREE_TYPE (expr) = type; |
8f5d16f2 | 255 | /* Fix up the representation of -1 if appropriate. */ |
256 | force_fit_type (expr, 0); | |
471086d6 | 257 | return expr; |
258 | } | |
259 | ||
bb0726a1 | 260 | if (INTEGRAL_CODE_P (form)) |
471086d6 | 261 | { |
c5aa1e92 | 262 | if (TYPE_PRECISION (intype) == POINTER_SIZE) |
471086d6 | 263 | return build1 (CONVERT_EXPR, type, expr); |
771d21fa | 264 | expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr); |
471086d6 | 265 | /* Modes may be different but sizes should be the same. */ |
266 | if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) | |
267 | != GET_MODE_SIZE (TYPE_MODE (type))) | |
268 | /* There is supposed to be some integral type | |
269 | that is the same width as a pointer. */ | |
270 | abort (); | |
271 | return convert_to_pointer (type, expr); | |
272 | } | |
273 | ||
cc4d0855 | 274 | if (type_unknown_p (expr)) |
4b471722 | 275 | return instantiate_type (type, expr, tf_error | tf_warning); |
cc4d0855 | 276 | |
cf103c6c | 277 | error ("cannot convert `%E' from type `%T' to type `%T'", |
471086d6 | 278 | expr, intype, type); |
279 | return error_mark_node; | |
280 | } | |
281 | ||
282 | /* Like convert, except permit conversions to take place which | |
283 | are not normally allowed due to access restrictions | |
284 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 285 | |
471086d6 | 286 | static tree |
287 | convert_to_pointer_force (type, expr) | |
288 | tree type, expr; | |
289 | { | |
290 | register tree intype = TREE_TYPE (expr); | |
291 | register enum tree_code form = TREE_CODE (intype); | |
292 | ||
471086d6 | 293 | if (form == POINTER_TYPE) |
294 | { | |
295 | intype = TYPE_MAIN_VARIANT (intype); | |
296 | ||
297 | if (TYPE_MAIN_VARIANT (type) != intype | |
298 | && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE | |
bccffb3a | 299 | && IS_AGGR_TYPE (TREE_TYPE (type)) |
300 | && IS_AGGR_TYPE (TREE_TYPE (intype)) | |
471086d6 | 301 | && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
302 | { | |
303 | enum tree_code code = PLUS_EXPR; | |
4a2680fc | 304 | tree binfo; |
305 | ||
306 | binfo = lookup_base (TREE_TYPE (intype), TREE_TYPE (type), | |
307 | ba_ignore, NULL); | |
308 | if (!binfo) | |
471086d6 | 309 | { |
4a2680fc | 310 | binfo = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), |
311 | ba_ignore, NULL); | |
312 | code = MINUS_EXPR; | |
471086d6 | 313 | } |
4a2680fc | 314 | if (binfo == error_mark_node) |
315 | return error_mark_node; | |
316 | if (binfo) | |
471086d6 | 317 | { |
4a2680fc | 318 | expr = build_base_path (code, expr, binfo, 0); |
319 | /* Add any qualifier conversions. */ | |
320 | if (!same_type_p (TREE_TYPE (TREE_TYPE (expr)), | |
321 | TREE_TYPE (type))) | |
322 | { | |
323 | expr = build1 (NOP_EXPR, type, expr); | |
324 | TREE_CONSTANT (expr) = | |
325 | TREE_CONSTANT (TREE_OPERAND (expr, 0)); | |
326 | } | |
327 | return expr; | |
471086d6 | 328 | } |
4a2680fc | 329 | |
471086d6 | 330 | } |
471086d6 | 331 | } |
332 | ||
045ed8f8 | 333 | return cp_convert_to_pointer (type, expr, 1); |
471086d6 | 334 | } |
335 | ||
336 | /* We are passing something to a function which requires a reference. | |
337 | The type we are interested in is in TYPE. The initial | |
338 | value we have to begin with is in ARG. | |
339 | ||
340 | FLAGS controls how we manage access checking. | |
ca106ab1 | 341 | DIRECT_BIND in FLAGS controls how any temporaries are generated. |
342 | If DIRECT_BIND is set, DECL is the reference we're binding to. */ | |
96624a9e | 343 | |
471086d6 | 344 | static tree |
ca106ab1 | 345 | build_up_reference (type, arg, flags, decl) |
346 | tree type, arg, decl; | |
6a44e72e | 347 | int flags; |
471086d6 | 348 | { |
c76251c1 | 349 | tree rval; |
0543e7a9 | 350 | tree argtype = TREE_TYPE (arg); |
471086d6 | 351 | tree target_type = TREE_TYPE (type); |
c23ebfdd | 352 | tree stmt_expr = NULL_TREE; |
471086d6 | 353 | |
354 | my_friendly_assert (TREE_CODE (type) == REFERENCE_TYPE, 187); | |
471086d6 | 355 | |
c76251c1 | 356 | if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
471086d6 | 357 | { |
ca106ab1 | 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. */ | |
c76251c1 | 360 | tree targ = arg; |
ca106ab1 | 361 | |
362 | arg = build_decl (VAR_DECL, NULL_TREE, argtype); | |
363 | DECL_ARTIFICIAL (arg) = 1; | |
364 | TREE_USED (arg) = 1; | |
365 | TREE_STATIC (arg) = TREE_STATIC (decl); | |
366 | ||
367 | if (TREE_STATIC (decl)) | |
368 | { | |
369 | /* Namespace-scope or local static; give it a mangled name. */ | |
370 | tree name = mangle_ref_init_variable (decl); | |
371 | DECL_NAME (arg) = name; | |
372 | SET_DECL_ASSEMBLER_NAME (arg, name); | |
373 | arg = pushdecl_top_level (arg); | |
374 | } | |
471086d6 | 375 | else |
376 | { | |
243adba6 | 377 | /* Automatic; make sure we handle the cleanup properly. */ |
614cc70d | 378 | maybe_push_cleanup_level (argtype); |
ca106ab1 | 379 | arg = pushdecl (arg); |
1ad432f2 | 380 | } |
c23ebfdd | 381 | |
382 | /* Process the initializer for the declaration. */ | |
38281c46 | 383 | DECL_INITIAL (arg) = targ; |
ce23987e | 384 | cp_finish_decl (arg, targ, NULL_TREE, |
011310f7 | 385 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
1ad432f2 | 386 | } |
c76251c1 | 387 | else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
1d8e4310 | 388 | return get_target_expr (arg); |
1ad432f2 | 389 | |
ca106ab1 | 390 | /* If we had a way to wrap this up, and say, if we ever needed its |
b0df6589 | 391 | address, transform all occurrences of the register, into a memory |
392 | reference we could win better. */ | |
c76251c1 | 393 | rval = build_unary_op (ADDR_EXPR, arg, 1); |
15e55420 | 394 | if (rval == error_mark_node) |
395 | return error_mark_node; | |
396 | ||
6686e84d | 397 | if ((flags & LOOKUP_PROTECT) |
398 | && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) | |
399 | && IS_AGGR_TYPE (argtype) | |
400 | && IS_AGGR_TYPE (target_type)) | |
401 | { | |
7e6960e0 | 402 | /* We go through lookup_base for the access control. */ |
4a2680fc | 403 | tree binfo = lookup_base (argtype, target_type, ba_check, NULL); |
6686e84d | 404 | if (binfo == error_mark_node) |
405 | return error_mark_node; | |
406 | if (binfo == NULL_TREE) | |
407 | return error_not_base_type (target_type, argtype); | |
4a2680fc | 408 | rval = build_base_path (PLUS_EXPR, rval, binfo, 1); |
6686e84d | 409 | } |
c76251c1 | 410 | else |
411 | rval | |
412 | = convert_to_pointer_force (build_pointer_type (target_type), rval); | |
6686e84d | 413 | rval = build1 (NOP_EXPR, type, rval); |
c76251c1 | 414 | TREE_CONSTANT (rval) = TREE_CONSTANT (TREE_OPERAND (rval, 0)); |
c23ebfdd | 415 | |
416 | /* If we created and initialized a new temporary variable, add the | |
417 | representation of that initialization to the RVAL. */ | |
418 | if (stmt_expr) | |
419 | rval = build (COMPOUND_EXPR, TREE_TYPE (rval), stmt_expr, rval); | |
420 | ||
421 | /* And return the result. */ | |
471086d6 | 422 | return rval; |
423 | } | |
424 | ||
519ba62c | 425 | /* Subroutine of convert_to_reference. REFTYPE is the target reference type. |
426 | INTYPE is the original rvalue type and DECL is an optional _DECL node | |
427 | for diagnostics. | |
428 | ||
429 | [dcl.init.ref] says that if an rvalue is used to | |
430 | initialize a reference, then the reference must be to a | |
431 | non-volatile const type. */ | |
432 | ||
433 | static void | |
434 | warn_ref_binding (reftype, intype, decl) | |
435 | tree reftype, intype, decl; | |
436 | { | |
437 | tree ttl = TREE_TYPE (reftype); | |
438 | ||
439 | if (!CP_TYPE_CONST_NON_VOLATILE_P (ttl)) | |
440 | { | |
441 | const char *msg; | |
442 | ||
443 | if (CP_TYPE_VOLATILE_P (ttl) && decl) | |
444 | msg = "initialization of volatile reference type `%#T' from rvalue of type `%T'"; | |
445 | else if (CP_TYPE_VOLATILE_P (ttl)) | |
446 | msg = "conversion to volatile reference type `%#T' from rvalue of type `%T'"; | |
447 | else if (decl) | |
448 | msg = "initialization of non-const reference type `%#T' from rvalue of type `%T'"; | |
449 | else | |
450 | msg = "conversion to non-const reference type `%#T' from rvalue of type `%T'"; | |
451 | ||
cf103c6c | 452 | pedwarn (msg, reftype, intype); |
519ba62c | 453 | } |
454 | } | |
455 | ||
471086d6 | 456 | /* For C++: Only need to do one-level references, but cannot |
457 | get tripped up on signed/unsigned differences. | |
458 | ||
d81e00a4 | 459 | DECL is either NULL_TREE or the _DECL node for a reference that is being |
460 | initialized. It can be error_mark_node if we don't know the _DECL but | |
461 | we know it's an initialization. */ | |
471086d6 | 462 | |
471086d6 | 463 | tree |
d81e00a4 | 464 | convert_to_reference (reftype, expr, convtype, flags, decl) |
471086d6 | 465 | tree reftype, expr; |
d81e00a4 | 466 | int convtype, flags; |
467 | tree decl; | |
471086d6 | 468 | { |
469 | register tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); | |
470 | register tree intype = TREE_TYPE (expr); | |
471086d6 | 471 | tree rval = NULL_TREE; |
1a3f833b | 472 | tree rval_as_conversion = NULL_TREE; |
473 | int i; | |
474 | ||
cc4d0855 | 475 | if (TREE_CODE (type) == FUNCTION_TYPE && intype == unknown_type_node) |
476 | { | |
3effa7a7 | 477 | expr = instantiate_type (type, expr, |
ffe5bd74 | 478 | (flags & LOOKUP_COMPLAIN) |
4b471722 | 479 | ? tf_error | tf_warning : tf_none); |
3effa7a7 | 480 | if (expr == error_mark_node) |
481 | return error_mark_node; | |
482 | ||
cc4d0855 | 483 | intype = TREE_TYPE (expr); |
484 | } | |
485 | ||
8bc57e28 | 486 | my_friendly_assert (TREE_CODE (intype) != REFERENCE_TYPE, 364); |
471086d6 | 487 | |
471086d6 | 488 | intype = TYPE_MAIN_VARIANT (intype); |
489 | ||
1a3f833b | 490 | i = comp_target_types (type, intype, 0); |
491 | ||
492 | if (i <= 0 && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) | |
493 | && ! (flags & LOOKUP_NO_CONVERSION)) | |
494 | { | |
495 | /* Look for a user-defined conversion to lvalue that we can use. */ | |
496 | ||
0a4be248 | 497 | rval_as_conversion |
1c16607c | 498 | = build_type_conversion (reftype, expr, 1); |
1a3f833b | 499 | |
500 | if (rval_as_conversion && rval_as_conversion != error_mark_node | |
501 | && real_lvalue_p (rval_as_conversion)) | |
502 | { | |
503 | expr = rval_as_conversion; | |
504 | rval_as_conversion = NULL_TREE; | |
505 | intype = type; | |
506 | i = 1; | |
507 | } | |
508 | } | |
509 | ||
510 | if (((convtype & CONV_STATIC) && i == -1) | |
511 | || ((convtype & CONV_IMPLICIT) && i == 1)) | |
471086d6 | 512 | { |
471086d6 | 513 | if (flags & LOOKUP_COMPLAIN) |
514 | { | |
bc3887cf | 515 | tree ttl = TREE_TYPE (reftype); |
cb0ba4ec | 516 | tree ttr = lvalue_type (expr); |
471086d6 | 517 | |
519ba62c | 518 | if (! real_lvalue_p (expr)) |
519 | warn_ref_binding (reftype, intype, decl); | |
520 | ||
521 | if (! (convtype & CONV_CONST) | |
3e04bd45 | 522 | && !at_least_as_qualified_p (ttl, ttr)) |
cf103c6c | 523 | pedwarn ("conversion from `%T' to `%T' discards qualifiers", |
caa99b15 | 524 | ttr, reftype); |
0543e7a9 | 525 | } |
526 | ||
ca106ab1 | 527 | return build_up_reference (reftype, expr, flags, decl); |
471086d6 | 528 | } |
c07b1ad1 | 529 | else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
0543e7a9 | 530 | { |
531 | /* When casting an lvalue to a reference type, just convert into | |
532 | a pointer to the new type and deference it. This is allowed | |
e581f478 | 533 | by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
0543e7a9 | 534 | should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
e581f478 | 535 | |
3748625f | 536 | /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
e581f478 | 537 | meant. */ |
1a3f833b | 538 | if (TREE_CODE (intype) == POINTER_TYPE |
daf9ff67 | 539 | && (comptypes (TREE_TYPE (intype), type, |
540 | COMPARE_BASE | COMPARE_RELAXED ))) | |
cf103c6c | 541 | warning ("casting `%T' to `%T' does not dereference pointer", |
e581f478 | 542 | intype, reftype); |
543 | ||
0543e7a9 | 544 | rval = build_unary_op (ADDR_EXPR, expr, 0); |
545 | if (rval != error_mark_node) | |
985e9ee0 | 546 | rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), |
547 | rval, 0); | |
0543e7a9 | 548 | if (rval != error_mark_node) |
b0722fac | 549 | rval = build1 (NOP_EXPR, reftype, rval); |
0543e7a9 | 550 | } |
0a4be248 | 551 | else |
860740a7 | 552 | { |
553 | rval = convert_for_initialization (NULL_TREE, type, expr, flags, | |
554 | "converting", 0, 0); | |
a66fe4cb | 555 | if (rval == NULL_TREE || rval == error_mark_node) |
556 | return rval; | |
519ba62c | 557 | warn_ref_binding (reftype, intype, decl); |
ca106ab1 | 558 | rval = build_up_reference (reftype, rval, flags, decl); |
860740a7 | 559 | } |
471086d6 | 560 | |
561 | if (rval) | |
562 | { | |
96624a9e | 563 | /* If we found a way to convert earlier, then use it. */ |
471086d6 | 564 | return rval; |
565 | } | |
566 | ||
1a3f833b | 567 | my_friendly_assert (TREE_CODE (intype) != OFFSET_TYPE, 189); |
471086d6 | 568 | |
b248d3f7 | 569 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 570 | error ("cannot convert type `%T' to type `%T'", intype, reftype); |
b248d3f7 | 571 | |
471086d6 | 572 | if (flags & LOOKUP_SPECULATIVELY) |
573 | return NULL_TREE; | |
574 | ||
575 | return error_mark_node; | |
576 | } | |
577 | ||
578 | /* We are using a reference VAL for its value. Bash that reference all the | |
96624a9e | 579 | way down to its lowest form. */ |
580 | ||
471086d6 | 581 | tree |
582 | convert_from_reference (val) | |
583 | tree val; | |
584 | { | |
585 | tree type = TREE_TYPE (val); | |
586 | ||
587 | if (TREE_CODE (type) == OFFSET_TYPE) | |
588 | type = TREE_TYPE (type); | |
8c5c575d | 589 | if (TREE_CODE (type) == REFERENCE_TYPE) |
4d698345 | 590 | return build_indirect_ref (val, NULL); |
471086d6 | 591 | return val; |
592 | } | |
dbacd3bd | 593 | |
594 | /* Implicitly convert the lvalue EXPR to another lvalue of type TOTYPE, | |
595 | preserving cv-qualification. */ | |
596 | ||
597 | tree | |
598 | convert_lvalue (totype, expr) | |
599 | tree totype, expr; | |
600 | { | |
601 | totype = cp_build_qualified_type (totype, TYPE_QUALS (TREE_TYPE (expr))); | |
602 | totype = build_reference_type (totype); | |
603 | expr = convert_to_reference (totype, expr, CONV_IMPLICIT, LOOKUP_NORMAL, | |
604 | NULL_TREE); | |
605 | return convert_from_reference (expr); | |
606 | } | |
471086d6 | 607 | \f |
c4a8ac95 | 608 | /* C++ conversions, preference to static cast conversions. */ |
609 | ||
610 | tree | |
611 | cp_convert (type, expr) | |
612 | tree type, expr; | |
613 | { | |
614 | return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); | |
615 | } | |
616 | ||
b248d3f7 | 617 | /* Conversion... |
618 | ||
619 | FLAGS indicates how we should behave. */ | |
620 | ||
471086d6 | 621 | tree |
c4a8ac95 | 622 | ocp_convert (type, expr, convtype, flags) |
471086d6 | 623 | tree type, expr; |
d81e00a4 | 624 | int convtype, flags; |
471086d6 | 625 | { |
626 | register tree e = expr; | |
627 | register enum tree_code code = TREE_CODE (type); | |
628 | ||
b465397d | 629 | if (e == error_mark_node |
630 | || TREE_TYPE (e) == error_mark_node) | |
471086d6 | 631 | return error_mark_node; |
d81e00a4 | 632 | |
5b592939 | 633 | complete_type (type); |
634 | complete_type (TREE_TYPE (expr)); | |
635 | ||
1202e392 | 636 | e = decl_constant_value (e); |
7745052b | 637 | |
2133b374 | 638 | if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP) |
639 | /* Some internal structures (vtable_entry_type, sigtbl_ptr_type) | |
640 | don't go through finish_struct, so they don't have the synthesized | |
641 | constructors. So don't force a temporary. */ | |
642 | && TYPE_HAS_CONSTRUCTOR (type)) | |
1a3f833b | 643 | /* We need a new temporary; don't take this shortcut. */; |
644 | else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) | |
ca23ec64 | 645 | { |
daf9ff67 | 646 | if (same_type_p (type, TREE_TYPE (e))) |
ca23ec64 | 647 | /* The call to fold will not always remove the NOP_EXPR as |
648 | might be expected, since if one of the types is a typedef; | |
649 | the comparsion in fold is just equality of pointers, not a | |
f699c174 | 650 | call to comptypes. We don't call fold in this case because |
651 | that can result in infinite recursion; fold will call | |
652 | convert, which will call ocp_convert, etc. */ | |
653 | return e; | |
372e0e29 | 654 | /* For complex data types, we need to perform componentwise |
655 | conversion. */ | |
656 | else if (TREE_CODE (type) == COMPLEX_TYPE) | |
657 | return fold (convert_to_complex (type, e)); | |
ca23ec64 | 658 | else |
f699c174 | 659 | return fold (build1 (NOP_EXPR, type, e)); |
ca23ec64 | 660 | } |
661 | ||
d81e00a4 | 662 | if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
95b2ac55 | 663 | { |
b1a8d4ce | 664 | e = convert_to_void (e, /*implicit=*/NULL); |
aeef2be5 | 665 | return e; |
95b2ac55 | 666 | } |
d81e00a4 | 667 | |
471086d6 | 668 | /* Just convert to the type of the member. */ |
669 | if (code == OFFSET_TYPE) | |
670 | { | |
671 | type = TREE_TYPE (type); | |
672 | code = TREE_CODE (type); | |
673 | } | |
674 | ||
f3ba5c6a | 675 | if (TREE_CODE (e) == OFFSET_REF) |
676 | e = resolve_offset_ref (e); | |
677 | ||
bb0726a1 | 678 | if (INTEGRAL_CODE_P (code)) |
471086d6 | 679 | { |
617abf06 | 680 | tree intype = TREE_TYPE (e); |
02d7f858 | 681 | /* enum = enum, enum = int, enum = float, (enum)pointer are all |
682 | errors. */ | |
723d9ad3 | 683 | if (TREE_CODE (type) == ENUMERAL_TYPE |
02d7f858 | 684 | && ((ARITHMETIC_TYPE_P (intype) && ! (convtype & CONV_STATIC)) |
685 | || (TREE_CODE (intype) == POINTER_TYPE))) | |
471086d6 | 686 | { |
cf103c6c | 687 | pedwarn ("conversion from `%#T' to `%#T'", intype, type); |
471086d6 | 688 | |
689 | if (flag_pedantic_errors) | |
690 | return error_mark_node; | |
691 | } | |
f3ba5c6a | 692 | if (IS_AGGR_TYPE (intype)) |
471086d6 | 693 | { |
694 | tree rval; | |
1c16607c | 695 | rval = build_type_conversion (type, e, 1); |
6495357a | 696 | if (rval) |
697 | return rval; | |
b248d3f7 | 698 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 699 | error ("`%#T' used where a `%T' was expected", intype, type); |
b248d3f7 | 700 | if (flags & LOOKUP_SPECULATIVELY) |
701 | return NULL_TREE; | |
471086d6 | 702 | return error_mark_node; |
703 | } | |
bb0726a1 | 704 | if (code == BOOLEAN_TYPE) |
e4ce2dc4 | 705 | { |
5b592939 | 706 | tree fn = NULL_TREE; |
707 | ||
e4ce2dc4 | 708 | /* Common Ada/Pascal programmer's mistake. We always warn |
709 | about this since it is so bad. */ | |
710 | if (TREE_CODE (expr) == FUNCTION_DECL) | |
5b592939 | 711 | fn = expr; |
712 | else if (TREE_CODE (expr) == ADDR_EXPR | |
713 | && TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL) | |
714 | fn = TREE_OPERAND (expr, 0); | |
1d2ca10c | 715 | if (fn && !DECL_WEAK (fn)) |
cf103c6c | 716 | warning ("the address of `%D', will always be `true'", fn); |
2e0e6579 | 717 | return cp_truthvalue_conversion (e); |
e4ce2dc4 | 718 | } |
471086d6 | 719 | return fold (convert_to_integer (type, e)); |
720 | } | |
74002e1d | 721 | if (code == POINTER_TYPE || code == REFERENCE_TYPE |
722 | || TYPE_PTRMEMFUNC_P (type)) | |
045ed8f8 | 723 | return fold (cp_convert_to_pointer (type, e, 0)); |
684b9d79 | 724 | if (code == VECTOR_TYPE) |
725 | return fold (convert_to_vector (type, e)); | |
c4a8ac95 | 726 | if (code == REAL_TYPE || code == COMPLEX_TYPE) |
471086d6 | 727 | { |
728 | if (IS_AGGR_TYPE (TREE_TYPE (e))) | |
729 | { | |
730 | tree rval; | |
1c16607c | 731 | rval = build_type_conversion (type, e, 1); |
471086d6 | 732 | if (rval) |
733 | return rval; | |
734 | else | |
b248d3f7 | 735 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 736 | error ("`%#T' used where a floating point value was expected", |
b248d3f7 | 737 | TREE_TYPE (e)); |
471086d6 | 738 | } |
c4a8ac95 | 739 | if (code == REAL_TYPE) |
740 | return fold (convert_to_real (type, e)); | |
741 | else if (code == COMPLEX_TYPE) | |
742 | return fold (convert_to_complex (type, e)); | |
471086d6 | 743 | } |
744 | ||
745 | /* New C++ semantics: since assignment is now based on | |
746 | memberwise copying, if the rhs type is derived from the | |
747 | lhs type, then we may still do a conversion. */ | |
748 | if (IS_AGGR_TYPE_CODE (code)) | |
749 | { | |
750 | tree dtype = TREE_TYPE (e); | |
c25194fd | 751 | tree ctor = NULL_TREE; |
471086d6 | 752 | |
471086d6 | 753 | dtype = TYPE_MAIN_VARIANT (dtype); |
754 | ||
471086d6 | 755 | /* Conversion between aggregate types. New C++ semantics allow |
756 | objects of derived type to be cast to objects of base type. | |
757 | Old semantics only allowed this between pointers. | |
758 | ||
759 | There may be some ambiguity between using a constructor | |
760 | vs. using a type conversion operator when both apply. */ | |
761 | ||
0a4be248 | 762 | ctor = e; |
860740a7 | 763 | |
8c18e707 | 764 | if (abstract_virtuals_error (NULL_TREE, type)) |
765 | return error_mark_node; | |
6cbb4197 | 766 | |
0a4be248 | 767 | if ((flags & LOOKUP_ONLYCONVERTING) |
768 | && ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype))) | |
fce73460 | 769 | /* For copy-initialization, first we create a temp of the proper type |
770 | with a user-defined conversion sequence, then we direct-initialize | |
771 | the target with the temp (see [dcl.init]). */ | |
772 | ctor = build_user_type_conversion (type, ctor, flags); | |
3eb89cd8 | 773 | else |
f70cb9e6 | 774 | ctor = build_special_member_call (NULL_TREE, |
775 | complete_ctor_identifier, | |
776 | build_tree_list (NULL_TREE, ctor), | |
777 | TYPE_BINFO (type), flags); | |
0a4be248 | 778 | if (ctor) |
779 | return build_cplus_new (type, ctor); | |
471086d6 | 780 | } |
781 | ||
b248d3f7 | 782 | if (flags & LOOKUP_COMPLAIN) |
cf103c6c | 783 | error ("conversion from `%T' to non-scalar type `%T' requested", |
b248d3f7 | 784 | TREE_TYPE (expr), type); |
785 | if (flags & LOOKUP_SPECULATIVELY) | |
786 | return NULL_TREE; | |
471086d6 | 787 | return error_mark_node; |
788 | } | |
789 | ||
b1a8d4ce | 790 | /* When an expression is used in a void context, its value is discarded and |
791 | no lvalue-rvalue and similar conversions happen [expr.static.cast/4, | |
792 | stmt.expr/1, expr.comma/1]. This permits dereferencing an incomplete type | |
793 | in a void context. The C++ standard does not define what an `access' to an | |
794 | object is, but there is reason to beleive that it is the lvalue to rvalue | |
795 | conversion -- if it were not, `*&*p = 1' would violate [expr]/4 in that it | |
796 | accesses `*p' not to calculate the value to be stored. But, dcl.type.cv/8 | |
797 | indicates that volatile semantics should be the same between C and C++ | |
798 | where ever possible. C leaves it implementation defined as to what | |
799 | constitutes an access to a volatile. So, we interpret `*vp' as a read of | |
800 | the volatile object `vp' points to, unless that is an incomplete type. For | |
801 | volatile references we do not do this interpretation, because that would | |
802 | make it impossible to ignore the reference return value from functions. We | |
803 | issue warnings in the confusing cases. | |
804 | ||
805 | IMPLICIT is tells us the context of an implicit void conversion. */ | |
806 | ||
807 | tree | |
808 | convert_to_void (expr, implicit) | |
809 | tree expr; | |
810 | const char *implicit; | |
811 | { | |
3d411d73 | 812 | if (expr == error_mark_node |
813 | || TREE_TYPE (expr) == error_mark_node) | |
814 | return error_mark_node; | |
b1a8d4ce | 815 | if (!TREE_TYPE (expr)) |
816 | return expr; | |
e3cfe3ce | 817 | if (VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 818 | return expr; |
819 | switch (TREE_CODE (expr)) | |
820 | { | |
821 | case COND_EXPR: | |
822 | { | |
823 | /* The two parts of a cond expr might be separate lvalues. */ | |
824 | tree op1 = TREE_OPERAND (expr,1); | |
825 | tree op2 = TREE_OPERAND (expr,2); | |
826 | tree new_op1 = convert_to_void (op1, implicit); | |
827 | tree new_op2 = convert_to_void (op2, implicit); | |
828 | ||
1b9a507b | 829 | expr = build (COND_EXPR, TREE_TYPE (new_op1), |
69773da0 | 830 | TREE_OPERAND (expr, 0), new_op1, new_op2); |
b1a8d4ce | 831 | break; |
832 | } | |
833 | ||
834 | case COMPOUND_EXPR: | |
835 | { | |
836 | /* The second part of a compound expr contains the value. */ | |
837 | tree op1 = TREE_OPERAND (expr,1); | |
838 | tree new_op1 = convert_to_void (op1, implicit); | |
839 | ||
840 | if (new_op1 != op1) | |
e907a2e9 | 841 | { |
842 | tree t = build (COMPOUND_EXPR, TREE_TYPE (new_op1), | |
843 | TREE_OPERAND (expr, 0), new_op1); | |
844 | TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (expr); | |
8061c68f | 845 | TREE_NO_UNUSED_WARNING (t) = TREE_NO_UNUSED_WARNING (expr); |
e907a2e9 | 846 | expr = t; |
847 | } | |
848 | ||
b1a8d4ce | 849 | break; |
850 | } | |
851 | ||
852 | case NON_LVALUE_EXPR: | |
853 | case NOP_EXPR: | |
854 | /* These have already decayed to rvalue. */ | |
855 | break; | |
856 | ||
857 | case CALL_EXPR: /* we have a special meaning for volatile void fn() */ | |
858 | break; | |
859 | ||
860 | case INDIRECT_REF: | |
861 | { | |
862 | tree type = TREE_TYPE (expr); | |
863 | int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
864 | == REFERENCE_TYPE; | |
865 | int is_volatile = TYPE_VOLATILE (type); | |
4b72716d | 866 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 867 | |
868 | if (is_volatile && !is_complete) | |
cf103c6c | 869 | warning ("object of incomplete type `%T' will not be accessed in %s", |
b1a8d4ce | 870 | type, implicit ? implicit : "void context"); |
871 | else if (is_reference && is_volatile) | |
cf103c6c | 872 | warning ("object of type `%T' will not be accessed in %s", |
b1a8d4ce | 873 | TREE_TYPE (TREE_OPERAND (expr, 0)), |
874 | implicit ? implicit : "void context"); | |
875 | if (is_reference || !is_volatile || !is_complete) | |
876 | expr = TREE_OPERAND (expr, 0); | |
877 | ||
878 | break; | |
879 | } | |
880 | ||
881 | case VAR_DECL: | |
882 | { | |
883 | /* External variables might be incomplete. */ | |
884 | tree type = TREE_TYPE (expr); | |
4b72716d | 885 | int is_complete = COMPLETE_TYPE_P (complete_type (type)); |
b1a8d4ce | 886 | |
887 | if (TYPE_VOLATILE (type) && !is_complete) | |
cf103c6c | 888 | warning ("object `%E' of incomplete type `%T' will not be accessed in %s", |
b1a8d4ce | 889 | expr, type, implicit ? implicit : "void context"); |
890 | break; | |
891 | } | |
d9f88785 | 892 | |
893 | case OFFSET_REF: | |
894 | expr = resolve_offset_ref (expr); | |
895 | break; | |
896 | ||
b1a8d4ce | 897 | default:; |
898 | } | |
899 | { | |
900 | tree probe = expr; | |
901 | ||
902 | if (TREE_CODE (probe) == ADDR_EXPR) | |
903 | probe = TREE_OPERAND (expr, 0); | |
2e0e6579 | 904 | if (type_unknown_p (probe)) |
905 | { | |
906 | /* [over.over] enumerates the places where we can take the address | |
907 | of an overloaded function, and this is not one of them. */ | |
cf103c6c | 908 | pedwarn ("%s cannot resolve address of overloaded function", |
2e0e6579 | 909 | implicit ? implicit : "void cast"); |
910 | } | |
911 | else if (implicit && probe == expr && is_overloaded_fn (probe)) | |
b1a8d4ce | 912 | /* Only warn when there is no &. */ |
cf103c6c | 913 | warning ("%s is a reference, not call, to function `%E'", |
2e0e6579 | 914 | implicit, expr); |
b1a8d4ce | 915 | } |
916 | ||
e3cfe3ce | 917 | if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr))) |
b1a8d4ce | 918 | { |
919 | /* FIXME: This is where we should check for expressions with no | |
920 | effects. At the moment we do that in both build_x_component_expr | |
921 | and expand_expr_stmt -- inconsistently too. For the moment | |
922 | leave implicit void conversions unadorned so that expand_expr_stmt | |
923 | has a chance of detecting some of the cases. */ | |
924 | if (!implicit) | |
925 | expr = build1 (CONVERT_EXPR, void_type_node, expr); | |
926 | } | |
927 | return expr; | |
928 | } | |
929 | ||
d81e00a4 | 930 | /* Create an expression whose value is that of EXPR, |
931 | converted to type TYPE. The TREE_TYPE of the value | |
932 | is always TYPE. This function implements all reasonable | |
933 | conversions; callers should filter out those that are | |
c4a8ac95 | 934 | not permitted by the language being compiled. |
935 | ||
936 | Most of this routine is from build_reinterpret_cast. | |
937 | ||
938 | The backend cannot call cp_convert (what was convert) because | |
939 | conversions to/from basetypes may involve memory references | |
940 | (vbases) and adding or subtracting small values (multiple | |
941 | inheritance), but it calls convert from the constant folding code | |
e0aa5007 | 942 | on subtrees of already built trees after it has ripped them apart. |
c4a8ac95 | 943 | |
944 | Also, if we ever support range variables, we'll probably also have to | |
945 | do a little bit more work. */ | |
d81e00a4 | 946 | |
947 | tree | |
948 | convert (type, expr) | |
949 | tree type, expr; | |
950 | { | |
c4a8ac95 | 951 | tree intype; |
952 | ||
953 | if (type == error_mark_node || expr == error_mark_node) | |
954 | return error_mark_node; | |
955 | ||
c4a8ac95 | 956 | intype = TREE_TYPE (expr); |
957 | ||
6686e84d | 958 | if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
c4a8ac95 | 959 | { |
1202e392 | 960 | expr = decl_constant_value (expr); |
c4a8ac95 | 961 | return fold (build1 (NOP_EXPR, type, expr)); |
962 | } | |
963 | ||
964 | return ocp_convert (type, expr, CONV_OLD_CONVERT, | |
965 | LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); | |
d81e00a4 | 966 | } |
967 | ||
c4a8ac95 | 968 | /* Like cp_convert, except permit conversions to take place which |
471086d6 | 969 | are not normally allowed due to access restrictions |
970 | (such as conversion from sub-type to private super-type). */ | |
96624a9e | 971 | |
471086d6 | 972 | tree |
a74e8896 | 973 | convert_force (type, expr, convtype) |
471086d6 | 974 | tree type; |
975 | tree expr; | |
a74e8896 | 976 | int convtype; |
471086d6 | 977 | { |
978 | register tree e = expr; | |
979 | register enum tree_code code = TREE_CODE (type); | |
980 | ||
981 | if (code == REFERENCE_TYPE) | |
d81e00a4 | 982 | return fold (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, |
983 | NULL_TREE)); | |
471086d6 | 984 | else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) |
985 | e = convert_from_reference (e); | |
986 | ||
987 | if (code == POINTER_TYPE) | |
988 | return fold (convert_to_pointer_force (type, e)); | |
989 | ||
ac9386a0 | 990 | /* From typeck.c convert_for_assignment */ |
471086d6 | 991 | if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
992 | && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE | |
993 | && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) | |
ac9386a0 | 994 | || integer_zerop (e) |
995 | || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) | |
471086d6 | 996 | && TYPE_PTRMEMFUNC_P (type)) |
997 | { | |
96624a9e | 998 | /* compatible pointer to member functions. */ |
ac9386a0 | 999 | return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1); |
471086d6 | 1000 | } |
a74e8896 | 1001 | |
c4a8ac95 | 1002 | return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
471086d6 | 1003 | } |
1004 | ||
471086d6 | 1005 | /* Convert an aggregate EXPR to type XTYPE. If a conversion |
1006 | exists, return the attempted conversion. This may | |
1007 | return ERROR_MARK_NODE if the conversion is not | |
1008 | allowed (references private members, etc). | |
1009 | If no conversion exists, NULL_TREE is returned. | |
1010 | ||
1011 | If (FOR_SURE & 1) is non-zero, then we allow this type conversion | |
1012 | to take place immediately. Otherwise, we build a SAVE_EXPR | |
ce28ee2e | 1013 | which can be evaluated if the results are ever needed. |
1014 | ||
1015 | Changes to this functions should be mirrored in user_harshness. | |
1016 | ||
1017 | FIXME: Ambiguity checking is wrong. Should choose one by the implicit | |
1018 | object parameter, or by the second standard conversion sequence if | |
1019 | that doesn't do it. This will probably wait for an overloading rewrite. | |
1020 | (jason 8/9/95) */ | |
471086d6 | 1021 | |
471086d6 | 1022 | tree |
1c16607c | 1023 | build_type_conversion (xtype, expr, for_sure) |
471086d6 | 1024 | tree xtype, expr; |
1025 | int for_sure; | |
1026 | { | |
1027 | /* C++: check to see if we can convert this aggregate type | |
bcf789d7 | 1028 | into the required type. */ |
0a4be248 | 1029 | return build_user_type_conversion |
1030 | (xtype, expr, for_sure ? LOOKUP_NORMAL : 0); | |
471086d6 | 1031 | } |
1032 | ||
1e66592c | 1033 | /* Convert the given EXPR to one of a group of types suitable for use in an |
1034 | expression. DESIRES is a combination of various WANT_* flags (q.v.) | |
1035 | which indicates which types are suitable. If COMPLAIN is 1, complain | |
1036 | about ambiguity; otherwise, the caller will deal with it. */ | |
471086d6 | 1037 | |
1e66592c | 1038 | tree |
1039 | build_expr_type_conversion (desires, expr, complain) | |
1040 | int desires; | |
1041 | tree expr; | |
1042 | int complain; | |
471086d6 | 1043 | { |
1e66592c | 1044 | tree basetype = TREE_TYPE (expr); |
6a44e72e | 1045 | tree conv = NULL_TREE; |
bdd152ce | 1046 | tree winner = NULL_TREE; |
471086d6 | 1047 | |
954885ed | 1048 | if (expr == null_node |
1049 | && (desires & WANT_INT) | |
1050 | && !(desires & WANT_NULL)) | |
cf103c6c | 1051 | warning ("converting NULL to non-pointer type"); |
954885ed | 1052 | |
42b9ec6a | 1053 | if (TREE_CODE (expr) == OFFSET_REF) |
ce28ee2e | 1054 | expr = resolve_offset_ref (expr); |
1055 | expr = convert_from_reference (expr); | |
1056 | basetype = TREE_TYPE (expr); | |
471086d6 | 1057 | |
3d411d73 | 1058 | if (basetype == error_mark_node) |
1059 | return error_mark_node; | |
1060 | ||
bdd152ce | 1061 | if (! IS_AGGR_TYPE (basetype)) |
1062 | switch (TREE_CODE (basetype)) | |
1063 | { | |
1064 | case INTEGER_TYPE: | |
954885ed | 1065 | if ((desires & WANT_NULL) && null_ptr_cst_p (expr)) |
bdd152ce | 1066 | return expr; |
1067 | /* else fall through... */ | |
1068 | ||
1069 | case BOOLEAN_TYPE: | |
1070 | return (desires & WANT_INT) ? expr : NULL_TREE; | |
1071 | case ENUMERAL_TYPE: | |
1072 | return (desires & WANT_ENUM) ? expr : NULL_TREE; | |
1073 | case REAL_TYPE: | |
1074 | return (desires & WANT_FLOAT) ? expr : NULL_TREE; | |
1075 | case POINTER_TYPE: | |
1076 | return (desires & WANT_POINTER) ? expr : NULL_TREE; | |
985e9ee0 | 1077 | |
bdd152ce | 1078 | case FUNCTION_TYPE: |
1079 | case ARRAY_TYPE: | |
1080 | return (desires & WANT_POINTER) ? default_conversion (expr) | |
1081 | : NULL_TREE; | |
1082 | default: | |
1083 | return NULL_TREE; | |
1084 | } | |
1085 | ||
1086 | /* The code for conversions from class type is currently only used for | |
1087 | delete expressions. Other expressions are handled by build_new_op. */ | |
1088 | ||
1089 | if (! TYPE_HAS_CONVERSION (basetype)) | |
1090 | return NULL_TREE; | |
1091 | ||
1092 | for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) | |
1093 | { | |
1094 | int win = 0; | |
1095 | tree candidate; | |
1096 | tree cand = TREE_VALUE (conv); | |
1097 | ||
1098 | if (winner && winner == cand) | |
1099 | continue; | |
1100 | ||
1101 | candidate = TREE_TYPE (TREE_TYPE (cand)); | |
1102 | if (TREE_CODE (candidate) == REFERENCE_TYPE) | |
1103 | candidate = TREE_TYPE (candidate); | |
1104 | ||
1105 | switch (TREE_CODE (candidate)) | |
1106 | { | |
1107 | case BOOLEAN_TYPE: | |
1108 | case INTEGER_TYPE: | |
1109 | win = (desires & WANT_INT); break; | |
1110 | case ENUMERAL_TYPE: | |
1111 | win = (desires & WANT_ENUM); break; | |
1112 | case REAL_TYPE: | |
1113 | win = (desires & WANT_FLOAT); break; | |
1114 | case POINTER_TYPE: | |
1115 | win = (desires & WANT_POINTER); break; | |
1116 | ||
1117 | default: | |
1118 | break; | |
1119 | } | |
1120 | ||
1121 | if (win) | |
1122 | { | |
1123 | if (winner) | |
1124 | { | |
1125 | if (complain) | |
1126 | { | |
cf103c6c | 1127 | error ("ambiguous default type conversion from `%T'", |
bdd152ce | 1128 | basetype); |
cf103c6c | 1129 | error (" candidate conversions include `%D' and `%D'", |
bdd152ce | 1130 | winner, cand); |
1131 | } | |
1132 | return error_mark_node; | |
1133 | } | |
1134 | else | |
1135 | winner = cand; | |
1136 | } | |
1137 | } | |
1e66592c | 1138 | |
bdd152ce | 1139 | if (winner) |
1140 | { | |
1141 | tree type = TREE_TYPE (TREE_TYPE (winner)); | |
1142 | if (TREE_CODE (type) == REFERENCE_TYPE) | |
1143 | type = TREE_TYPE (type); | |
1144 | return build_user_type_conversion (type, expr, LOOKUP_NORMAL); | |
471086d6 | 1145 | } |
1e66592c | 1146 | |
985e9ee0 | 1147 | return NULL_TREE; |
471086d6 | 1148 | } |
bc3887cf | 1149 | |
96624a9e | 1150 | /* Implements integral promotion (4.1) and float->double promotion. */ |
1151 | ||
bc3887cf | 1152 | tree |
1153 | type_promotes_to (type) | |
1154 | tree type; | |
1155 | { | |
3e04bd45 | 1156 | int type_quals; |
ce28ee2e | 1157 | |
1158 | if (type == error_mark_node) | |
1159 | return error_mark_node; | |
1160 | ||
3119c950 | 1161 | type_quals = cp_type_quals (type); |
bc3887cf | 1162 | type = TYPE_MAIN_VARIANT (type); |
bb0726a1 | 1163 | |
1164 | /* bool always promotes to int (not unsigned), even if it's the same | |
1165 | size. */ | |
028ea8b4 | 1166 | if (type == boolean_type_node) |
bb0726a1 | 1167 | type = integer_type_node; |
1168 | ||
1169 | /* Normally convert enums to int, but convert wide enums to something | |
1170 | wider. */ | |
1171 | else if (TREE_CODE (type) == ENUMERAL_TYPE | |
1172 | || type == wchar_type_node) | |
6c9497b1 | 1173 | { |
1174 | int precision = MAX (TYPE_PRECISION (type), | |
1175 | TYPE_PRECISION (integer_type_node)); | |
771d21fa | 1176 | tree totype = c_common_type_for_size (precision, 0); |
6c9497b1 | 1177 | if (TREE_UNSIGNED (type) |
1178 | && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) | |
771d21fa | 1179 | type = c_common_type_for_size (precision, 1); |
6c9497b1 | 1180 | else |
1181 | type = totype; | |
1182 | } | |
d7aeef06 | 1183 | else if (c_promoting_integer_type_p (type)) |
bc3887cf | 1184 | { |
d0acef9e | 1185 | /* Retain unsignedness if really not getting bigger. */ |
bc3887cf | 1186 | if (TREE_UNSIGNED (type) |
d0acef9e | 1187 | && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
bc3887cf | 1188 | type = unsigned_type_node; |
1189 | else | |
1190 | type = integer_type_node; | |
1191 | } | |
1192 | else if (type == float_type_node) | |
1193 | type = double_type_node; | |
1194 | ||
3e04bd45 | 1195 | return cp_build_qualified_type (type, type_quals); |
bc3887cf | 1196 | } |
668ae905 | 1197 | |
668ae905 | 1198 | /* The routines below this point are carefully written to conform to |
1199 | the standard. They use the same terminology, and follow the rules | |
1200 | closely. Although they are used only in pt.c at the moment, they | |
1201 | should presumably be used everywhere in the future. */ | |
1202 | ||
1146f179 | 1203 | /* Attempt to perform qualification conversions on EXPR to convert it |
1204 | to TYPE. Return the resulting expression, or error_mark_node if | |
1205 | the conversion was impossible. */ | |
1206 | ||
668ae905 | 1207 | tree |
1208 | perform_qualification_conversions (type, expr) | |
1209 | tree type; | |
1210 | tree expr; | |
1211 | { | |
213d2076 | 1212 | if (TREE_CODE (type) == POINTER_TYPE |
1213 | && TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE | |
1214 | && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (TREE_TYPE (expr)))) | |
1146f179 | 1215 | return build1 (NOP_EXPR, type, expr); |
1216 | else | |
1217 | return error_mark_node; | |
668ae905 | 1218 | } |