typeck.c revision 259705
1/* Build expressions with type checking for C++ compiler. 2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 3 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. 4 Hacked by Michael Tiemann (tiemann@cygnus.com) 5 6This file is part of GCC. 7 8GCC is free software; you can redistribute it and/or modify 9it under the terms of the GNU General Public License as published by 10the Free Software Foundation; either version 2, or (at your option) 11any later version. 12 13GCC is distributed in the hope that it will be useful, 14but WITHOUT ANY WARRANTY; without even the implied warranty of 15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16GNU General Public License for more details. 17 18You should have received a copy of the GNU General Public License 19along with GCC; see the file COPYING. If not, write to 20the Free Software Foundation, 51 Franklin Street, Fifth Floor, 21Boston, MA 02110-1301, USA. */ 22 23 24/* This file is part of the C++ front end. 25 It contains routines to build C++ expressions given their operands, 26 including computing the types of the result, C and C++ specific error 27 checks, and some optimization. */ 28 29#include "config.h" 30#include "system.h" 31#include "coretypes.h" 32#include "tm.h" 33#include "tree.h" 34#include "rtl.h" 35#include "expr.h" 36#include "cp-tree.h" 37#include "tm_p.h" 38#include "flags.h" 39#include "output.h" 40#include "toplev.h" 41#include "diagnostic.h" 42#include "target.h" 43#include "convert.h" 44#include "c-common.h" 45 46static tree pfn_from_ptrmemfunc (tree); 47static tree convert_for_assignment (tree, tree, const char *, tree, int); 48static tree cp_pointer_int_sum (enum tree_code, tree, tree); 49static tree rationalize_conditional_expr (enum tree_code, tree); 50static int comp_ptr_ttypes_real (tree, tree, int); 51static bool comp_except_types (tree, tree, bool); 52static bool comp_array_types (tree, tree, bool); 53static tree common_base_type (tree, tree); 54static tree pointer_diff (tree, tree, tree); 55static tree get_delta_difference (tree, tree, bool, bool); 56static void casts_away_constness_r (tree *, tree *); 57static bool casts_away_constness (tree, tree); 58static void maybe_warn_about_returning_address_of_local (tree); 59static tree lookup_destructor (tree, tree, tree); 60static tree convert_arguments (tree, tree, tree, int); 61 62/* Do `exp = require_complete_type (exp);' to make sure exp 63 does not have an incomplete type. (That includes void types.) 64 Returns the error_mark_node if the VALUE does not have 65 complete type when this function returns. */ 66 67tree 68require_complete_type (tree value) 69{ 70 tree type; 71 72 if (processing_template_decl || value == error_mark_node) 73 return value; 74 75 if (TREE_CODE (value) == OVERLOAD) 76 type = unknown_type_node; 77 else 78 type = TREE_TYPE (value); 79 80 if (type == error_mark_node) 81 return error_mark_node; 82 83 /* First, detect a valid value with a complete type. */ 84 if (COMPLETE_TYPE_P (type)) 85 return value; 86 87 if (complete_type_or_else (type, value)) 88 return value; 89 else 90 return error_mark_node; 91} 92 93/* Try to complete TYPE, if it is incomplete. For example, if TYPE is 94 a template instantiation, do the instantiation. Returns TYPE, 95 whether or not it could be completed, unless something goes 96 horribly wrong, in which case the error_mark_node is returned. */ 97 98tree 99complete_type (tree type) 100{ 101 if (type == NULL_TREE) 102 /* Rather than crash, we return something sure to cause an error 103 at some point. */ 104 return error_mark_node; 105 106 if (type == error_mark_node || COMPLETE_TYPE_P (type)) 107 ; 108 else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type)) 109 { 110 tree t = complete_type (TREE_TYPE (type)); 111 unsigned int needs_constructing, has_nontrivial_dtor; 112 if (COMPLETE_TYPE_P (t) && !dependent_type_p (type)) 113 layout_type (type); 114 needs_constructing 115 = TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (t)); 116 has_nontrivial_dtor 117 = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TYPE_MAIN_VARIANT (t)); 118 for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t)) 119 { 120 TYPE_NEEDS_CONSTRUCTING (t) = needs_constructing; 121 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t) = has_nontrivial_dtor; 122 } 123 } 124 else if (CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INSTANTIATION (type)) 125 instantiate_class_template (TYPE_MAIN_VARIANT (type)); 126 127 return type; 128} 129 130/* Like complete_type, but issue an error if the TYPE cannot be completed. 131 VALUE is used for informative diagnostics. 132 Returns NULL_TREE if the type cannot be made complete. */ 133 134tree 135complete_type_or_else (tree type, tree value) 136{ 137 type = complete_type (type); 138 if (type == error_mark_node) 139 /* We already issued an error. */ 140 return NULL_TREE; 141 else if (!COMPLETE_TYPE_P (type)) 142 { 143 cxx_incomplete_type_diagnostic (value, type, 0); 144 return NULL_TREE; 145 } 146 else 147 return type; 148} 149 150/* Return truthvalue of whether type of EXP is instantiated. */ 151 152int 153type_unknown_p (tree exp) 154{ 155 return (TREE_CODE (exp) == TREE_LIST 156 || TREE_TYPE (exp) == unknown_type_node); 157} 158 159 160/* Return the common type of two parameter lists. 161 We assume that comptypes has already been done and returned 1; 162 if that isn't so, this may crash. 163 164 As an optimization, free the space we allocate if the parameter 165 lists are already common. */ 166 167static tree 168commonparms (tree p1, tree p2) 169{ 170 tree oldargs = p1, newargs, n; 171 int i, len; 172 int any_change = 0; 173 174 len = list_length (p1); 175 newargs = tree_last (p1); 176 177 if (newargs == void_list_node) 178 i = 1; 179 else 180 { 181 i = 0; 182 newargs = 0; 183 } 184 185 for (; i < len; i++) 186 newargs = tree_cons (NULL_TREE, NULL_TREE, newargs); 187 188 n = newargs; 189 190 for (i = 0; p1; 191 p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n), i++) 192 { 193 if (TREE_PURPOSE (p1) && !TREE_PURPOSE (p2)) 194 { 195 TREE_PURPOSE (n) = TREE_PURPOSE (p1); 196 any_change = 1; 197 } 198 else if (! TREE_PURPOSE (p1)) 199 { 200 if (TREE_PURPOSE (p2)) 201 { 202 TREE_PURPOSE (n) = TREE_PURPOSE (p2); 203 any_change = 1; 204 } 205 } 206 else 207 { 208 if (1 != simple_cst_equal (TREE_PURPOSE (p1), TREE_PURPOSE (p2))) 209 any_change = 1; 210 TREE_PURPOSE (n) = TREE_PURPOSE (p2); 211 } 212 if (TREE_VALUE (p1) != TREE_VALUE (p2)) 213 { 214 any_change = 1; 215 TREE_VALUE (n) = merge_types (TREE_VALUE (p1), TREE_VALUE (p2)); 216 } 217 else 218 TREE_VALUE (n) = TREE_VALUE (p1); 219 } 220 if (! any_change) 221 return oldargs; 222 223 return newargs; 224} 225 226/* Given a type, perhaps copied for a typedef, 227 find the "original" version of it. */ 228static tree 229original_type (tree t) 230{ 231 int quals = cp_type_quals (t); 232 while (t != error_mark_node 233 && TYPE_NAME (t) != NULL_TREE) 234 { 235 tree x = TYPE_NAME (t); 236 if (TREE_CODE (x) != TYPE_DECL) 237 break; 238 x = DECL_ORIGINAL_TYPE (x); 239 if (x == NULL_TREE) 240 break; 241 t = x; 242 } 243 return cp_build_qualified_type (t, quals); 244} 245 246/* T1 and T2 are arithmetic or enumeration types. Return the type 247 that will result from the "usual arithmetic conversions" on T1 and 248 T2 as described in [expr]. */ 249 250tree 251type_after_usual_arithmetic_conversions (tree t1, tree t2) 252{ 253 enum tree_code code1 = TREE_CODE (t1); 254 enum tree_code code2 = TREE_CODE (t2); 255 tree attributes; 256 257 /* FIXME: Attributes. */ 258 gcc_assert (ARITHMETIC_TYPE_P (t1) 259 || TREE_CODE (t1) == VECTOR_TYPE 260 || TREE_CODE (t1) == ENUMERAL_TYPE); 261 gcc_assert (ARITHMETIC_TYPE_P (t2) 262 || TREE_CODE (t2) == VECTOR_TYPE 263 || TREE_CODE (t2) == ENUMERAL_TYPE); 264 265 /* In what follows, we slightly generalize the rules given in [expr] so 266 as to deal with `long long' and `complex'. First, merge the 267 attributes. */ 268 attributes = (*targetm.merge_type_attributes) (t1, t2); 269 270 /* If one type is complex, form the common type of the non-complex 271 components, then make that complex. Use T1 or T2 if it is the 272 required type. */ 273 if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE) 274 { 275 tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1; 276 tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2; 277 tree subtype 278 = type_after_usual_arithmetic_conversions (subtype1, subtype2); 279 280 if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype) 281 return build_type_attribute_variant (t1, attributes); 282 else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype) 283 return build_type_attribute_variant (t2, attributes); 284 else 285 return build_type_attribute_variant (build_complex_type (subtype), 286 attributes); 287 } 288 289 if (code1 == VECTOR_TYPE) 290 { 291 /* When we get here we should have two vectors of the same size. 292 Just prefer the unsigned one if present. */ 293 if (TYPE_UNSIGNED (t1)) 294 return build_type_attribute_variant (t1, attributes); 295 else 296 return build_type_attribute_variant (t2, attributes); 297 } 298 299 /* If only one is real, use it as the result. */ 300 if (code1 == REAL_TYPE && code2 != REAL_TYPE) 301 return build_type_attribute_variant (t1, attributes); 302 if (code2 == REAL_TYPE && code1 != REAL_TYPE) 303 return build_type_attribute_variant (t2, attributes); 304 305 /* Perform the integral promotions. */ 306 if (code1 != REAL_TYPE) 307 { 308 t1 = type_promotes_to (t1); 309 t2 = type_promotes_to (t2); 310 } 311 312 /* Both real or both integers; use the one with greater precision. */ 313 if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2)) 314 return build_type_attribute_variant (t1, attributes); 315 else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1)) 316 return build_type_attribute_variant (t2, attributes); 317 318 /* The types are the same; no need to do anything fancy. */ 319 if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2)) 320 return build_type_attribute_variant (t1, attributes); 321 322 if (code1 != REAL_TYPE) 323 { 324 /* If one is a sizetype, use it so size_binop doesn't blow up. */ 325 if (TYPE_IS_SIZETYPE (t1) > TYPE_IS_SIZETYPE (t2)) 326 return build_type_attribute_variant (t1, attributes); 327 if (TYPE_IS_SIZETYPE (t2) > TYPE_IS_SIZETYPE (t1)) 328 return build_type_attribute_variant (t2, attributes); 329 330 /* If one is unsigned long long, then convert the other to unsigned 331 long long. */ 332 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_unsigned_type_node) 333 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_unsigned_type_node)) 334 return build_type_attribute_variant (long_long_unsigned_type_node, 335 attributes); 336 /* If one is a long long, and the other is an unsigned long, and 337 long long can represent all the values of an unsigned long, then 338 convert to a long long. Otherwise, convert to an unsigned long 339 long. Otherwise, if either operand is long long, convert the 340 other to long long. 341 342 Since we're here, we know the TYPE_PRECISION is the same; 343 therefore converting to long long cannot represent all the values 344 of an unsigned long, so we choose unsigned long long in that 345 case. */ 346 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_integer_type_node) 347 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_integer_type_node)) 348 { 349 tree t = ((TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2)) 350 ? long_long_unsigned_type_node 351 : long_long_integer_type_node); 352 return build_type_attribute_variant (t, attributes); 353 } 354 355 /* Go through the same procedure, but for longs. */ 356 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_unsigned_type_node) 357 || same_type_p (TYPE_MAIN_VARIANT (t2), long_unsigned_type_node)) 358 return build_type_attribute_variant (long_unsigned_type_node, 359 attributes); 360 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_integer_type_node) 361 || same_type_p (TYPE_MAIN_VARIANT (t2), long_integer_type_node)) 362 { 363 tree t = ((TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2)) 364 ? long_unsigned_type_node : long_integer_type_node); 365 return build_type_attribute_variant (t, attributes); 366 } 367 /* Otherwise prefer the unsigned one. */ 368 if (TYPE_UNSIGNED (t1)) 369 return build_type_attribute_variant (t1, attributes); 370 else 371 return build_type_attribute_variant (t2, attributes); 372 } 373 else 374 { 375 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_double_type_node) 376 || same_type_p (TYPE_MAIN_VARIANT (t2), long_double_type_node)) 377 return build_type_attribute_variant (long_double_type_node, 378 attributes); 379 if (same_type_p (TYPE_MAIN_VARIANT (t1), double_type_node) 380 || same_type_p (TYPE_MAIN_VARIANT (t2), double_type_node)) 381 return build_type_attribute_variant (double_type_node, 382 attributes); 383 if (same_type_p (TYPE_MAIN_VARIANT (t1), float_type_node) 384 || same_type_p (TYPE_MAIN_VARIANT (t2), float_type_node)) 385 return build_type_attribute_variant (float_type_node, 386 attributes); 387 388 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of 389 the standard C++ floating-point types. Logic earlier in this 390 function has already eliminated the possibility that 391 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no 392 compelling reason to choose one or the other. */ 393 return build_type_attribute_variant (t1, attributes); 394 } 395} 396 397/* Subroutine of composite_pointer_type to implement the recursive 398 case. See that function for documentation fo the parameters. */ 399 400static tree 401composite_pointer_type_r (tree t1, tree t2, const char* location) 402{ 403 tree pointee1; 404 tree pointee2; 405 tree result_type; 406 tree attributes; 407 408 /* Determine the types pointed to by T1 and T2. */ 409 if (TREE_CODE (t1) == POINTER_TYPE) 410 { 411 pointee1 = TREE_TYPE (t1); 412 pointee2 = TREE_TYPE (t2); 413 } 414 else 415 { 416 pointee1 = TYPE_PTRMEM_POINTED_TO_TYPE (t1); 417 pointee2 = TYPE_PTRMEM_POINTED_TO_TYPE (t2); 418 } 419 420 /* [expr.rel] 421 422 Otherwise, the composite pointer type is a pointer type 423 similar (_conv.qual_) to the type of one of the operands, 424 with a cv-qualification signature (_conv.qual_) that is the 425 union of the cv-qualification signatures of the operand 426 types. */ 427 if (same_type_ignoring_top_level_qualifiers_p (pointee1, pointee2)) 428 result_type = pointee1; 429 else if ((TREE_CODE (pointee1) == POINTER_TYPE 430 && TREE_CODE (pointee2) == POINTER_TYPE) 431 || (TYPE_PTR_TO_MEMBER_P (pointee1) 432 && TYPE_PTR_TO_MEMBER_P (pointee2))) 433 result_type = composite_pointer_type_r (pointee1, pointee2, location); 434 else 435 { 436 pedwarn ("%s between distinct pointer types %qT and %qT " 437 "lacks a cast", 438 location, t1, t2); 439 result_type = void_type_node; 440 } 441 result_type = cp_build_qualified_type (result_type, 442 (cp_type_quals (pointee1) 443 | cp_type_quals (pointee2))); 444 /* If the original types were pointers to members, so is the 445 result. */ 446 if (TYPE_PTR_TO_MEMBER_P (t1)) 447 { 448 if (!same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1), 449 TYPE_PTRMEM_CLASS_TYPE (t2))) 450 pedwarn ("%s between distinct pointer types %qT and %qT " 451 "lacks a cast", 452 location, t1, t2); 453 result_type = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1), 454 result_type); 455 } 456 else 457 result_type = build_pointer_type (result_type); 458 459 /* Merge the attributes. */ 460 attributes = (*targetm.merge_type_attributes) (t1, t2); 461 return build_type_attribute_variant (result_type, attributes); 462} 463 464/* Return the composite pointer type (see [expr.rel]) for T1 and T2. 465 ARG1 and ARG2 are the values with those types. The LOCATION is a 466 string describing the current location, in case an error occurs. 467 468 This routine also implements the computation of a common type for 469 pointers-to-members as per [expr.eq]. */ 470 471tree 472composite_pointer_type (tree t1, tree t2, tree arg1, tree arg2, 473 const char* location) 474{ 475 tree class1; 476 tree class2; 477 478 /* [expr.rel] 479 480 If one operand is a null pointer constant, the composite pointer 481 type is the type of the other operand. */ 482 if (null_ptr_cst_p (arg1)) 483 return t2; 484 if (null_ptr_cst_p (arg2)) 485 return t1; 486 487 /* We have: 488 489 [expr.rel] 490 491 If one of the operands has type "pointer to cv1 void*", then 492 the other has type "pointer to cv2T", and the composite pointer 493 type is "pointer to cv12 void", where cv12 is the union of cv1 494 and cv2. 495 496 If either type is a pointer to void, make sure it is T1. */ 497 if (TREE_CODE (t2) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t2))) 498 { 499 tree t; 500 t = t1; 501 t1 = t2; 502 t2 = t; 503 } 504 505 /* Now, if T1 is a pointer to void, merge the qualifiers. */ 506 if (TREE_CODE (t1) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t1))) 507 { 508 tree attributes; 509 tree result_type; 510 511 if (pedantic && TYPE_PTRFN_P (t2)) 512 pedwarn ("ISO C++ forbids %s between pointer of type %<void *%> " 513 "and pointer-to-function", location); 514 result_type 515 = cp_build_qualified_type (void_type_node, 516 (cp_type_quals (TREE_TYPE (t1)) 517 | cp_type_quals (TREE_TYPE (t2)))); 518 result_type = build_pointer_type (result_type); 519 /* Merge the attributes. */ 520 attributes = (*targetm.merge_type_attributes) (t1, t2); 521 return build_type_attribute_variant (result_type, attributes); 522 } 523 524 if (c_dialect_objc () && TREE_CODE (t1) == POINTER_TYPE 525 && TREE_CODE (t2) == POINTER_TYPE) 526 { 527 if (objc_compare_types (t1, t2, -3, NULL_TREE)) 528 return t1; 529 } 530 531 /* [expr.eq] permits the application of a pointer conversion to 532 bring the pointers to a common type. */ 533 if (TREE_CODE (t1) == POINTER_TYPE && TREE_CODE (t2) == POINTER_TYPE 534 && CLASS_TYPE_P (TREE_TYPE (t1)) 535 && CLASS_TYPE_P (TREE_TYPE (t2)) 536 && !same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (t1), 537 TREE_TYPE (t2))) 538 { 539 class1 = TREE_TYPE (t1); 540 class2 = TREE_TYPE (t2); 541 542 if (DERIVED_FROM_P (class1, class2)) 543 t2 = (build_pointer_type 544 (cp_build_qualified_type (class1, TYPE_QUALS (class2)))); 545 else if (DERIVED_FROM_P (class2, class1)) 546 t1 = (build_pointer_type 547 (cp_build_qualified_type (class2, TYPE_QUALS (class1)))); 548 else 549 { 550 error ("%s between distinct pointer types %qT and %qT " 551 "lacks a cast", location, t1, t2); 552 return error_mark_node; 553 } 554 } 555 /* [expr.eq] permits the application of a pointer-to-member 556 conversion to change the class type of one of the types. */ 557 else if (TYPE_PTR_TO_MEMBER_P (t1) 558 && !same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1), 559 TYPE_PTRMEM_CLASS_TYPE (t2))) 560 { 561 class1 = TYPE_PTRMEM_CLASS_TYPE (t1); 562 class2 = TYPE_PTRMEM_CLASS_TYPE (t2); 563 564 if (DERIVED_FROM_P (class1, class2)) 565 t1 = build_ptrmem_type (class2, TYPE_PTRMEM_POINTED_TO_TYPE (t1)); 566 else if (DERIVED_FROM_P (class2, class1)) 567 t2 = build_ptrmem_type (class1, TYPE_PTRMEM_POINTED_TO_TYPE (t2)); 568 else 569 { 570 error ("%s between distinct pointer-to-member types %qT and %qT " 571 "lacks a cast", location, t1, t2); 572 return error_mark_node; 573 } 574 } 575 576 return composite_pointer_type_r (t1, t2, location); 577} 578 579/* Return the merged type of two types. 580 We assume that comptypes has already been done and returned 1; 581 if that isn't so, this may crash. 582 583 This just combines attributes and default arguments; any other 584 differences would cause the two types to compare unalike. */ 585 586tree 587merge_types (tree t1, tree t2) 588{ 589 enum tree_code code1; 590 enum tree_code code2; 591 tree attributes; 592 593 /* Save time if the two types are the same. */ 594 if (t1 == t2) 595 return t1; 596 if (original_type (t1) == original_type (t2)) 597 return t1; 598 599 /* If one type is nonsense, use the other. */ 600 if (t1 == error_mark_node) 601 return t2; 602 if (t2 == error_mark_node) 603 return t1; 604 605 /* Merge the attributes. */ 606 attributes = (*targetm.merge_type_attributes) (t1, t2); 607 608 if (TYPE_PTRMEMFUNC_P (t1)) 609 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1); 610 if (TYPE_PTRMEMFUNC_P (t2)) 611 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2); 612 613 code1 = TREE_CODE (t1); 614 code2 = TREE_CODE (t2); 615 616 switch (code1) 617 { 618 case POINTER_TYPE: 619 case REFERENCE_TYPE: 620 /* For two pointers, do this recursively on the target type. */ 621 { 622 tree target = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 623 int quals = cp_type_quals (t1); 624 625 if (code1 == POINTER_TYPE) 626 t1 = build_pointer_type (target); 627 else 628 t1 = build_reference_type (target); 629 t1 = build_type_attribute_variant (t1, attributes); 630 t1 = cp_build_qualified_type (t1, quals); 631 632 if (TREE_CODE (target) == METHOD_TYPE) 633 t1 = build_ptrmemfunc_type (t1); 634 635 return t1; 636 } 637 638 case OFFSET_TYPE: 639 { 640 int quals; 641 tree pointee; 642 quals = cp_type_quals (t1); 643 pointee = merge_types (TYPE_PTRMEM_POINTED_TO_TYPE (t1), 644 TYPE_PTRMEM_POINTED_TO_TYPE (t2)); 645 t1 = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1), 646 pointee); 647 t1 = cp_build_qualified_type (t1, quals); 648 break; 649 } 650 651 case ARRAY_TYPE: 652 { 653 tree elt = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 654 /* Save space: see if the result is identical to one of the args. */ 655 if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)) 656 return build_type_attribute_variant (t1, attributes); 657 if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)) 658 return build_type_attribute_variant (t2, attributes); 659 /* Merge the element types, and have a size if either arg has one. */ 660 t1 = build_cplus_array_type 661 (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2)); 662 break; 663 } 664 665 case FUNCTION_TYPE: 666 /* Function types: prefer the one that specified arg types. 667 If both do, merge the arg types. Also merge the return types. */ 668 { 669 tree valtype = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 670 tree p1 = TYPE_ARG_TYPES (t1); 671 tree p2 = TYPE_ARG_TYPES (t2); 672 tree rval, raises; 673 674 /* Save space: see if the result is identical to one of the args. */ 675 if (valtype == TREE_TYPE (t1) && ! p2) 676 return cp_build_type_attribute_variant (t1, attributes); 677 if (valtype == TREE_TYPE (t2) && ! p1) 678 return cp_build_type_attribute_variant (t2, attributes); 679 680 /* Simple way if one arg fails to specify argument types. */ 681 if (p1 == NULL_TREE || TREE_VALUE (p1) == void_type_node) 682 { 683 rval = build_function_type (valtype, p2); 684 if ((raises = TYPE_RAISES_EXCEPTIONS (t2))) 685 rval = build_exception_variant (rval, raises); 686 return cp_build_type_attribute_variant (rval, attributes); 687 } 688 raises = TYPE_RAISES_EXCEPTIONS (t1); 689 if (p2 == NULL_TREE || TREE_VALUE (p2) == void_type_node) 690 { 691 rval = build_function_type (valtype, p1); 692 if (raises) 693 rval = build_exception_variant (rval, raises); 694 return cp_build_type_attribute_variant (rval, attributes); 695 } 696 697 rval = build_function_type (valtype, commonparms (p1, p2)); 698 t1 = build_exception_variant (rval, raises); 699 break; 700 } 701 702 case METHOD_TYPE: 703 { 704 /* Get this value the long way, since TYPE_METHOD_BASETYPE 705 is just the main variant of this. */ 706 tree basetype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t2))); 707 tree raises = TYPE_RAISES_EXCEPTIONS (t1); 708 tree t3; 709 710 /* If this was a member function type, get back to the 711 original type of type member function (i.e., without 712 the class instance variable up front. */ 713 t1 = build_function_type (TREE_TYPE (t1), 714 TREE_CHAIN (TYPE_ARG_TYPES (t1))); 715 t2 = build_function_type (TREE_TYPE (t2), 716 TREE_CHAIN (TYPE_ARG_TYPES (t2))); 717 t3 = merge_types (t1, t2); 718 t3 = build_method_type_directly (basetype, TREE_TYPE (t3), 719 TYPE_ARG_TYPES (t3)); 720 t1 = build_exception_variant (t3, raises); 721 break; 722 } 723 724 case TYPENAME_TYPE: 725 /* There is no need to merge attributes into a TYPENAME_TYPE. 726 When the type is instantiated it will have whatever 727 attributes result from the instantiation. */ 728 return t1; 729 730 default:; 731 } 732 733 if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes)) 734 return t1; 735 else if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes)) 736 return t2; 737 else 738 return cp_build_type_attribute_variant (t1, attributes); 739} 740 741/* Return the common type of two types. 742 We assume that comptypes has already been done and returned 1; 743 if that isn't so, this may crash. 744 745 This is the type for the result of most arithmetic operations 746 if the operands have the given two types. */ 747 748tree 749common_type (tree t1, tree t2) 750{ 751 enum tree_code code1; 752 enum tree_code code2; 753 754 /* If one type is nonsense, bail. */ 755 if (t1 == error_mark_node || t2 == error_mark_node) 756 return error_mark_node; 757 758 code1 = TREE_CODE (t1); 759 code2 = TREE_CODE (t2); 760 761 if ((ARITHMETIC_TYPE_P (t1) || code1 == ENUMERAL_TYPE 762 || code1 == VECTOR_TYPE) 763 && (ARITHMETIC_TYPE_P (t2) || code2 == ENUMERAL_TYPE 764 || code2 == VECTOR_TYPE)) 765 return type_after_usual_arithmetic_conversions (t1, t2); 766 767 else if ((TYPE_PTR_P (t1) && TYPE_PTR_P (t2)) 768 || (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2)) 769 || (TYPE_PTRMEMFUNC_P (t1) && TYPE_PTRMEMFUNC_P (t2))) 770 return composite_pointer_type (t1, t2, error_mark_node, error_mark_node, 771 "conversion"); 772 else 773 gcc_unreachable (); 774} 775 776/* Compare two exception specifier types for exactness or subsetness, if 777 allowed. Returns false for mismatch, true for match (same, or 778 derived and !exact). 779 780 [except.spec] "If a class X ... objects of class X or any class publicly 781 and unambiguously derived from X. Similarly, if a pointer type Y * ... 782 exceptions of type Y * or that are pointers to any type publicly and 783 unambiguously derived from Y. Otherwise a function only allows exceptions 784 that have the same type ..." 785 This does not mention cv qualifiers and is different to what throw 786 [except.throw] and catch [except.catch] will do. They will ignore the 787 top level cv qualifiers, and allow qualifiers in the pointer to class 788 example. 789 790 We implement the letter of the standard. */ 791 792static bool 793comp_except_types (tree a, tree b, bool exact) 794{ 795 if (same_type_p (a, b)) 796 return true; 797 else if (!exact) 798 { 799 if (cp_type_quals (a) || cp_type_quals (b)) 800 return false; 801 802 if (TREE_CODE (a) == POINTER_TYPE 803 && TREE_CODE (b) == POINTER_TYPE) 804 { 805 a = TREE_TYPE (a); 806 b = TREE_TYPE (b); 807 if (cp_type_quals (a) || cp_type_quals (b)) 808 return false; 809 } 810 811 if (TREE_CODE (a) != RECORD_TYPE 812 || TREE_CODE (b) != RECORD_TYPE) 813 return false; 814 815 if (PUBLICLY_UNIQUELY_DERIVED_P (a, b)) 816 return true; 817 } 818 return false; 819} 820 821/* Return true if TYPE1 and TYPE2 are equivalent exception specifiers. 822 If EXACT is false, T2 can be stricter than T1 (according to 15.4/7), 823 otherwise it must be exact. Exception lists are unordered, but 824 we've already filtered out duplicates. Most lists will be in order, 825 we should try to make use of that. */ 826 827bool 828comp_except_specs (tree t1, tree t2, bool exact) 829{ 830 tree probe; 831 tree base; 832 int length = 0; 833 834 if (t1 == t2) 835 return true; 836 837 if (t1 == NULL_TREE) /* T1 is ... */ 838 return t2 == NULL_TREE || !exact; 839 if (!TREE_VALUE (t1)) /* t1 is EMPTY */ 840 return t2 != NULL_TREE && !TREE_VALUE (t2); 841 if (t2 == NULL_TREE) /* T2 is ... */ 842 return false; 843 if (TREE_VALUE (t1) && !TREE_VALUE (t2)) /* T2 is EMPTY, T1 is not */ 844 return !exact; 845 846 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1. 847 Count how many we find, to determine exactness. For exact matching and 848 ordered T1, T2, this is an O(n) operation, otherwise its worst case is 849 O(nm). */ 850 for (base = t1; t2 != NULL_TREE; t2 = TREE_CHAIN (t2)) 851 { 852 for (probe = base; probe != NULL_TREE; probe = TREE_CHAIN (probe)) 853 { 854 tree a = TREE_VALUE (probe); 855 tree b = TREE_VALUE (t2); 856 857 if (comp_except_types (a, b, exact)) 858 { 859 if (probe == base && exact) 860 base = TREE_CHAIN (probe); 861 length++; 862 break; 863 } 864 } 865 if (probe == NULL_TREE) 866 return false; 867 } 868 return !exact || base == NULL_TREE || length == list_length (t1); 869} 870 871/* Compare the array types T1 and T2. ALLOW_REDECLARATION is true if 872 [] can match [size]. */ 873 874static bool 875comp_array_types (tree t1, tree t2, bool allow_redeclaration) 876{ 877 tree d1; 878 tree d2; 879 tree max1, max2; 880 881 if (t1 == t2) 882 return true; 883 884 /* The type of the array elements must be the same. */ 885 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 886 return false; 887 888 d1 = TYPE_DOMAIN (t1); 889 d2 = TYPE_DOMAIN (t2); 890 891 if (d1 == d2) 892 return true; 893 894 /* If one of the arrays is dimensionless, and the other has a 895 dimension, they are of different types. However, it is valid to 896 write: 897 898 extern int a[]; 899 int a[3]; 900 901 by [basic.link]: 902 903 declarations for an array object can specify 904 array types that differ by the presence or absence of a major 905 array bound (_dcl.array_). */ 906 if (!d1 || !d2) 907 return allow_redeclaration; 908 909 /* Check that the dimensions are the same. */ 910 911 if (!cp_tree_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))) 912 return false; 913 max1 = TYPE_MAX_VALUE (d1); 914 max2 = TYPE_MAX_VALUE (d2); 915 if (processing_template_decl && !abi_version_at_least (2) 916 && !value_dependent_expression_p (max1) 917 && !value_dependent_expression_p (max2)) 918 { 919 /* With abi-1 we do not fold non-dependent array bounds, (and 920 consequently mangle them incorrectly). We must therefore 921 fold them here, to verify the domains have the same 922 value. */ 923 max1 = fold (max1); 924 max2 = fold (max2); 925 } 926 927 if (!cp_tree_equal (max1, max2)) 928 return false; 929 930 return true; 931} 932 933/* Return true if T1 and T2 are related as allowed by STRICT. STRICT 934 is a bitwise-or of the COMPARE_* flags. */ 935 936bool 937comptypes (tree t1, tree t2, int strict) 938{ 939 if (t1 == t2) 940 return true; 941 942 /* Suppress errors caused by previously reported errors. */ 943 if (t1 == error_mark_node || t2 == error_mark_node) 944 return false; 945 946 gcc_assert (TYPE_P (t1) && TYPE_P (t2)); 947 948 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the 949 current instantiation. */ 950 if (TREE_CODE (t1) == TYPENAME_TYPE) 951 { 952 tree resolved = resolve_typename_type (t1, /*only_current_p=*/true); 953 954 if (resolved != error_mark_node) 955 t1 = resolved; 956 } 957 958 if (TREE_CODE (t2) == TYPENAME_TYPE) 959 { 960 tree resolved = resolve_typename_type (t2, /*only_current_p=*/true); 961 962 if (resolved != error_mark_node) 963 t2 = resolved; 964 } 965 966 /* If either type is the internal version of sizetype, use the 967 language version. */ 968 if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1) 969 && TYPE_ORIG_SIZE_TYPE (t1)) 970 t1 = TYPE_ORIG_SIZE_TYPE (t1); 971 972 if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2) 973 && TYPE_ORIG_SIZE_TYPE (t2)) 974 t2 = TYPE_ORIG_SIZE_TYPE (t2); 975 976 if (TYPE_PTRMEMFUNC_P (t1)) 977 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1); 978 if (TYPE_PTRMEMFUNC_P (t2)) 979 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2); 980 981 /* Different classes of types can't be compatible. */ 982 if (TREE_CODE (t1) != TREE_CODE (t2)) 983 return false; 984 985 /* Qualifiers must match. For array types, we will check when we 986 recur on the array element types. */ 987 if (TREE_CODE (t1) != ARRAY_TYPE 988 && TYPE_QUALS (t1) != TYPE_QUALS (t2)) 989 return false; 990 if (TYPE_FOR_JAVA (t1) != TYPE_FOR_JAVA (t2)) 991 return false; 992 993 /* Allow for two different type nodes which have essentially the same 994 definition. Note that we already checked for equality of the type 995 qualifiers (just above). */ 996 997 if (TREE_CODE (t1) != ARRAY_TYPE 998 && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2)) 999 return true; 1000 1001 /* Compare the types. Break out if they could be the same. */ 1002 switch (TREE_CODE (t1)) 1003 { 1004 case TEMPLATE_TEMPLATE_PARM: 1005 case BOUND_TEMPLATE_TEMPLATE_PARM: 1006 if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2) 1007 || TEMPLATE_TYPE_LEVEL (t1) != TEMPLATE_TYPE_LEVEL (t2)) 1008 return false; 1009 if (!comp_template_parms 1010 (DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t1)), 1011 DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t2)))) 1012 return false; 1013 if (TREE_CODE (t1) == TEMPLATE_TEMPLATE_PARM) 1014 break; 1015 /* Don't check inheritance. */ 1016 strict = COMPARE_STRICT; 1017 /* Fall through. */ 1018 1019 case RECORD_TYPE: 1020 case UNION_TYPE: 1021 if (TYPE_TEMPLATE_INFO (t1) && TYPE_TEMPLATE_INFO (t2) 1022 && (TYPE_TI_TEMPLATE (t1) == TYPE_TI_TEMPLATE (t2) 1023 || TREE_CODE (t1) == BOUND_TEMPLATE_TEMPLATE_PARM) 1024 && comp_template_args (TYPE_TI_ARGS (t1), TYPE_TI_ARGS (t2))) 1025 break; 1026 1027 if ((strict & COMPARE_BASE) && DERIVED_FROM_P (t1, t2)) 1028 break; 1029 else if ((strict & COMPARE_DERIVED) && DERIVED_FROM_P (t2, t1)) 1030 break; 1031 1032 return false; 1033 1034 case OFFSET_TYPE: 1035 if (!comptypes (TYPE_OFFSET_BASETYPE (t1), TYPE_OFFSET_BASETYPE (t2), 1036 strict & ~COMPARE_REDECLARATION)) 1037 return false; 1038 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1039 return false; 1040 break; 1041 1042 case POINTER_TYPE: 1043 case REFERENCE_TYPE: 1044 if (TYPE_MODE (t1) != TYPE_MODE (t2) 1045 || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2) 1046 || !same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1047 return false; 1048 break; 1049 1050 case METHOD_TYPE: 1051 case FUNCTION_TYPE: 1052 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1053 return false; 1054 if (!compparms (TYPE_ARG_TYPES (t1), TYPE_ARG_TYPES (t2))) 1055 return false; 1056 break; 1057 1058 case ARRAY_TYPE: 1059 /* Target types must match incl. qualifiers. */ 1060 if (!comp_array_types (t1, t2, !!(strict & COMPARE_REDECLARATION))) 1061 return false; 1062 break; 1063 1064 case TEMPLATE_TYPE_PARM: 1065 if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2) 1066 || TEMPLATE_TYPE_LEVEL (t1) != TEMPLATE_TYPE_LEVEL (t2)) 1067 return false; 1068 break; 1069 1070 case TYPENAME_TYPE: 1071 if (!cp_tree_equal (TYPENAME_TYPE_FULLNAME (t1), 1072 TYPENAME_TYPE_FULLNAME (t2))) 1073 return false; 1074 if (!same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2))) 1075 return false; 1076 break; 1077 1078 case UNBOUND_CLASS_TEMPLATE: 1079 if (!cp_tree_equal (TYPE_IDENTIFIER (t1), TYPE_IDENTIFIER (t2))) 1080 return false; 1081 if (!same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2))) 1082 return false; 1083 break; 1084 1085 case COMPLEX_TYPE: 1086 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1087 return false; 1088 break; 1089 1090 case VECTOR_TYPE: 1091 if (TYPE_VECTOR_SUBPARTS (t1) != TYPE_VECTOR_SUBPARTS (t2) 1092 || !same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1093 return false; 1094 break; 1095 1096 default: 1097 return false; 1098 } 1099 1100 /* If we get here, we know that from a target independent POV the 1101 types are the same. Make sure the target attributes are also 1102 the same. */ 1103 return targetm.comp_type_attributes (t1, t2); 1104} 1105 1106/* Returns 1 if TYPE1 is at least as qualified as TYPE2. */ 1107 1108bool 1109at_least_as_qualified_p (tree type1, tree type2) 1110{ 1111 int q1 = cp_type_quals (type1); 1112 int q2 = cp_type_quals (type2); 1113 1114 /* All qualifiers for TYPE2 must also appear in TYPE1. */ 1115 return (q1 & q2) == q2; 1116} 1117 1118/* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is 1119 more cv-qualified that TYPE1, and 0 otherwise. */ 1120 1121int 1122comp_cv_qualification (tree type1, tree type2) 1123{ 1124 int q1 = cp_type_quals (type1); 1125 int q2 = cp_type_quals (type2); 1126 1127 if (q1 == q2) 1128 return 0; 1129 1130 if ((q1 & q2) == q2) 1131 return 1; 1132 else if ((q1 & q2) == q1) 1133 return -1; 1134 1135 return 0; 1136} 1137 1138/* Returns 1 if the cv-qualification signature of TYPE1 is a proper 1139 subset of the cv-qualification signature of TYPE2, and the types 1140 are similar. Returns -1 if the other way 'round, and 0 otherwise. */ 1141 1142int 1143comp_cv_qual_signature (tree type1, tree type2) 1144{ 1145 if (comp_ptr_ttypes_real (type2, type1, -1)) 1146 return 1; 1147 else if (comp_ptr_ttypes_real (type1, type2, -1)) 1148 return -1; 1149 else 1150 return 0; 1151} 1152 1153/* If two types share a common base type, return that basetype. 1154 If there is not a unique most-derived base type, this function 1155 returns ERROR_MARK_NODE. */ 1156 1157static tree 1158common_base_type (tree tt1, tree tt2) 1159{ 1160 tree best = NULL_TREE; 1161 int i; 1162 1163 /* If one is a baseclass of another, that's good enough. */ 1164 if (UNIQUELY_DERIVED_FROM_P (tt1, tt2)) 1165 return tt1; 1166 if (UNIQUELY_DERIVED_FROM_P (tt2, tt1)) 1167 return tt2; 1168 1169 /* Otherwise, try to find a unique baseclass of TT1 1170 that is shared by TT2, and follow that down. */ 1171 for (i = BINFO_N_BASE_BINFOS (TYPE_BINFO (tt1))-1; i >= 0; i--) 1172 { 1173 tree basetype = BINFO_TYPE (BINFO_BASE_BINFO (TYPE_BINFO (tt1), i)); 1174 tree trial = common_base_type (basetype, tt2); 1175 1176 if (trial) 1177 { 1178 if (trial == error_mark_node) 1179 return trial; 1180 if (best == NULL_TREE) 1181 best = trial; 1182 else if (best != trial) 1183 return error_mark_node; 1184 } 1185 } 1186 1187 /* Same for TT2. */ 1188 for (i = BINFO_N_BASE_BINFOS (TYPE_BINFO (tt2))-1; i >= 0; i--) 1189 { 1190 tree basetype = BINFO_TYPE (BINFO_BASE_BINFO (TYPE_BINFO (tt2), i)); 1191 tree trial = common_base_type (tt1, basetype); 1192 1193 if (trial) 1194 { 1195 if (trial == error_mark_node) 1196 return trial; 1197 if (best == NULL_TREE) 1198 best = trial; 1199 else if (best != trial) 1200 return error_mark_node; 1201 } 1202 } 1203 return best; 1204} 1205 1206/* Subroutines of `comptypes'. */ 1207 1208/* Return true if two parameter type lists PARMS1 and PARMS2 are 1209 equivalent in the sense that functions with those parameter types 1210 can have equivalent types. The two lists must be equivalent, 1211 element by element. */ 1212 1213bool 1214compparms (tree parms1, tree parms2) 1215{ 1216 tree t1, t2; 1217 1218 /* An unspecified parmlist matches any specified parmlist 1219 whose argument types don't need default promotions. */ 1220 1221 for (t1 = parms1, t2 = parms2; 1222 t1 || t2; 1223 t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2)) 1224 { 1225 /* If one parmlist is shorter than the other, 1226 they fail to match. */ 1227 if (!t1 || !t2) 1228 return false; 1229 if (!same_type_p (TREE_VALUE (t1), TREE_VALUE (t2))) 1230 return false; 1231 } 1232 return true; 1233} 1234 1235 1236/* Process a sizeof or alignof expression where the operand is a 1237 type. */ 1238 1239tree 1240cxx_sizeof_or_alignof_type (tree type, enum tree_code op, bool complain) 1241{ 1242 tree value; 1243 bool dependent_p; 1244 1245 gcc_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR); 1246 if (type == error_mark_node) 1247 return error_mark_node; 1248 1249 type = non_reference (type); 1250 if (TREE_CODE (type) == METHOD_TYPE) 1251 { 1252 if (complain && (pedantic || warn_pointer_arith)) 1253 pedwarn ("invalid application of %qs to a member function", 1254 operator_name_info[(int) op].name); 1255 value = size_one_node; 1256 } 1257 1258 dependent_p = dependent_type_p (type); 1259 if (!dependent_p) 1260 complete_type (type); 1261 if (dependent_p 1262 /* VLA types will have a non-constant size. In the body of an 1263 uninstantiated template, we don't need to try to compute the 1264 value, because the sizeof expression is not an integral 1265 constant expression in that case. And, if we do try to 1266 compute the value, we'll likely end up with SAVE_EXPRs, which 1267 the template substitution machinery does not expect to see. */ 1268 || (processing_template_decl 1269 && COMPLETE_TYPE_P (type) 1270 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)) 1271 { 1272 value = build_min (op, size_type_node, type); 1273 TREE_READONLY (value) = 1; 1274 return value; 1275 } 1276 1277 return c_sizeof_or_alignof_type (complete_type (type), 1278 op == SIZEOF_EXPR, 1279 complain); 1280} 1281 1282/* Process a sizeof expression where the operand is an expression. */ 1283 1284static tree 1285cxx_sizeof_expr (tree e) 1286{ 1287 if (e == error_mark_node) 1288 return error_mark_node; 1289 1290 if (processing_template_decl) 1291 { 1292 e = build_min (SIZEOF_EXPR, size_type_node, e); 1293 TREE_SIDE_EFFECTS (e) = 0; 1294 TREE_READONLY (e) = 1; 1295 1296 return e; 1297 } 1298 1299 if (TREE_CODE (e) == COMPONENT_REF 1300 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL 1301 && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1))) 1302 { 1303 error ("invalid application of %<sizeof%> to a bit-field"); 1304 e = char_type_node; 1305 } 1306 else if (is_overloaded_fn (e)) 1307 { 1308 pedwarn ("ISO C++ forbids applying %<sizeof%> to an expression of " 1309 "function type"); 1310 e = char_type_node; 1311 } 1312 else if (type_unknown_p (e)) 1313 { 1314 cxx_incomplete_type_error (e, TREE_TYPE (e)); 1315 e = char_type_node; 1316 } 1317 else 1318 e = TREE_TYPE (e); 1319 1320 return cxx_sizeof_or_alignof_type (e, SIZEOF_EXPR, true); 1321} 1322 1323/* Implement the __alignof keyword: Return the minimum required 1324 alignment of E, measured in bytes. For VAR_DECL's and 1325 FIELD_DECL's return DECL_ALIGN (which can be set from an 1326 "aligned" __attribute__ specification). */ 1327 1328static tree 1329cxx_alignof_expr (tree e) 1330{ 1331 tree t; 1332 1333 if (e == error_mark_node) 1334 return error_mark_node; 1335 1336 if (processing_template_decl) 1337 { 1338 e = build_min (ALIGNOF_EXPR, size_type_node, e); 1339 TREE_SIDE_EFFECTS (e) = 0; 1340 TREE_READONLY (e) = 1; 1341 1342 return e; 1343 } 1344 1345 if (TREE_CODE (e) == VAR_DECL) 1346 t = size_int (DECL_ALIGN_UNIT (e)); 1347 else if (TREE_CODE (e) == COMPONENT_REF 1348 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL 1349 && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1))) 1350 { 1351 error ("invalid application of %<__alignof%> to a bit-field"); 1352 t = size_one_node; 1353 } 1354 else if (TREE_CODE (e) == COMPONENT_REF 1355 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL) 1356 t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (e, 1))); 1357 else if (is_overloaded_fn (e)) 1358 { 1359 pedwarn ("ISO C++ forbids applying %<__alignof%> to an expression of " 1360 "function type"); 1361 if (TREE_CODE (e) == FUNCTION_DECL) 1362 t = size_int (DECL_ALIGN_UNIT (e)); 1363 else 1364 t = size_one_node; 1365 } 1366 else if (type_unknown_p (e)) 1367 { 1368 cxx_incomplete_type_error (e, TREE_TYPE (e)); 1369 t = size_one_node; 1370 } 1371 else 1372 return cxx_sizeof_or_alignof_type (TREE_TYPE (e), ALIGNOF_EXPR, true); 1373 1374 return fold_convert (size_type_node, t); 1375} 1376 1377/* Process a sizeof or alignof expression E with code OP where the operand 1378 is an expression. */ 1379 1380tree 1381cxx_sizeof_or_alignof_expr (tree e, enum tree_code op) 1382{ 1383 if (op == SIZEOF_EXPR) 1384 return cxx_sizeof_expr (e); 1385 else 1386 return cxx_alignof_expr (e); 1387} 1388 1389/* EXPR is being used in a context that is not a function call. 1390 Enforce: 1391 1392 [expr.ref] 1393 1394 The expression can be used only as the left-hand operand of a 1395 member function call. 1396 1397 [expr.mptr.operator] 1398 1399 If the result of .* or ->* is a function, then that result can be 1400 used only as the operand for the function call operator (). 1401 1402 by issuing an error message if appropriate. Returns true iff EXPR 1403 violates these rules. */ 1404 1405bool 1406invalid_nonstatic_memfn_p (tree expr) 1407{ 1408 if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) 1409 { 1410 error ("invalid use of non-static member function"); 1411 return true; 1412 } 1413 return false; 1414} 1415 1416/* If EXP is a reference to a bitfield, and the type of EXP does not 1417 match the declared type of the bitfield, return the declared type 1418 of the bitfield. Otherwise, return NULL_TREE. */ 1419 1420tree 1421is_bitfield_expr_with_lowered_type (tree exp) 1422{ 1423 switch (TREE_CODE (exp)) 1424 { 1425 case COND_EXPR: 1426 if (!is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 1))) 1427 return NULL_TREE; 1428 return is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 2)); 1429 1430 case COMPOUND_EXPR: 1431 return is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 1)); 1432 1433 case MODIFY_EXPR: 1434 case SAVE_EXPR: 1435 return is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 0)); 1436 1437 case COMPONENT_REF: 1438 { 1439 tree field; 1440 1441 field = TREE_OPERAND (exp, 1); 1442 if (TREE_CODE (field) != FIELD_DECL || !DECL_C_BIT_FIELD (field)) 1443 return NULL_TREE; 1444 if (same_type_ignoring_top_level_qualifiers_p 1445 (TREE_TYPE (exp), DECL_BIT_FIELD_TYPE (field))) 1446 return NULL_TREE; 1447 return DECL_BIT_FIELD_TYPE (field); 1448 } 1449 1450 default: 1451 return NULL_TREE; 1452 } 1453} 1454 1455/* Like is_bitfield_with_lowered_type, except that if EXP is not a 1456 bitfield with a lowered type, the type of EXP is returned, rather 1457 than NULL_TREE. */ 1458 1459tree 1460unlowered_expr_type (tree exp) 1461{ 1462 tree type; 1463 1464 type = is_bitfield_expr_with_lowered_type (exp); 1465 if (!type) 1466 type = TREE_TYPE (exp); 1467 1468 return type; 1469} 1470 1471/* Perform the conversions in [expr] that apply when an lvalue appears 1472 in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and 1473 function-to-pointer conversions. In addition, manifest constants 1474 are replaced by their values, and bitfield references are converted 1475 to their declared types. 1476 1477 Although the returned value is being used as an rvalue, this 1478 function does not wrap the returned expression in a 1479 NON_LVALUE_EXPR; the caller is expected to be mindful of the fact 1480 that the return value is no longer an lvalue. */ 1481 1482tree 1483decay_conversion (tree exp) 1484{ 1485 tree type; 1486 enum tree_code code; 1487 1488 type = TREE_TYPE (exp); 1489 if (type == error_mark_node) 1490 return error_mark_node; 1491 1492 if (type_unknown_p (exp)) 1493 { 1494 cxx_incomplete_type_error (exp, TREE_TYPE (exp)); 1495 return error_mark_node; 1496 } 1497 1498 exp = decl_constant_value (exp); 1499 if (error_operand_p (exp)) 1500 return error_mark_node; 1501 1502 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 1503 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */ 1504 code = TREE_CODE (type); 1505 if (code == VOID_TYPE) 1506 { 1507 error ("void value not ignored as it ought to be"); 1508 return error_mark_node; 1509 } 1510 if (invalid_nonstatic_memfn_p (exp)) 1511 return error_mark_node; 1512 if (code == FUNCTION_TYPE || is_overloaded_fn (exp)) 1513 return build_unary_op (ADDR_EXPR, exp, 0); 1514 if (code == ARRAY_TYPE) 1515 { 1516 tree adr; 1517 tree ptrtype; 1518 1519 if (TREE_CODE (exp) == INDIRECT_REF) 1520 return build_nop (build_pointer_type (TREE_TYPE (type)), 1521 TREE_OPERAND (exp, 0)); 1522 1523 if (TREE_CODE (exp) == COMPOUND_EXPR) 1524 { 1525 tree op1 = decay_conversion (TREE_OPERAND (exp, 1)); 1526 return build2 (COMPOUND_EXPR, TREE_TYPE (op1), 1527 TREE_OPERAND (exp, 0), op1); 1528 } 1529 1530 if (!lvalue_p (exp) 1531 && ! (TREE_CODE (exp) == CONSTRUCTOR && TREE_STATIC (exp))) 1532 { 1533 error ("invalid use of non-lvalue array"); 1534 return error_mark_node; 1535 } 1536 1537 ptrtype = build_pointer_type (TREE_TYPE (type)); 1538 1539 if (TREE_CODE (exp) == VAR_DECL) 1540 { 1541 if (!cxx_mark_addressable (exp)) 1542 return error_mark_node; 1543 adr = build_nop (ptrtype, build_address (exp)); 1544 return adr; 1545 } 1546 /* This way is better for a COMPONENT_REF since it can 1547 simplify the offset for a component. */ 1548 adr = build_unary_op (ADDR_EXPR, exp, 1); 1549 return cp_convert (ptrtype, adr); 1550 } 1551 1552 /* If a bitfield is used in a context where integral promotion 1553 applies, then the caller is expected to have used 1554 default_conversion. That function promotes bitfields correctly 1555 before calling this function. At this point, if we have a 1556 bitfield referenced, we may assume that is not subject to 1557 promotion, and that, therefore, the type of the resulting rvalue 1558 is the declared type of the bitfield. */ 1559 exp = convert_bitfield_to_declared_type (exp); 1560 1561 /* We do not call rvalue() here because we do not want to wrap EXP 1562 in a NON_LVALUE_EXPR. */ 1563 1564 /* [basic.lval] 1565 1566 Non-class rvalues always have cv-unqualified types. */ 1567 type = TREE_TYPE (exp); 1568 if (!CLASS_TYPE_P (type) && cp_type_quals (type)) 1569 exp = build_nop (TYPE_MAIN_VARIANT (type), exp); 1570 1571 return exp; 1572} 1573 1574/* Perform prepatory conversions, as part of the "usual arithmetic 1575 conversions". In particular, as per [expr]: 1576 1577 Whenever an lvalue expression appears as an operand of an 1578 operator that expects the rvalue for that operand, the 1579 lvalue-to-rvalue, array-to-pointer, or function-to-pointer 1580 standard conversions are applied to convert the expression to an 1581 rvalue. 1582 1583 In addition, we perform integral promotions here, as those are 1584 applied to both operands to a binary operator before determining 1585 what additional conversions should apply. */ 1586 1587tree 1588default_conversion (tree exp) 1589{ 1590 /* Perform the integral promotions first so that bitfield 1591 expressions (which may promote to "int", even if the bitfield is 1592 declared "unsigned") are promoted correctly. */ 1593 if (INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (exp))) 1594 exp = perform_integral_promotions (exp); 1595 /* Perform the other conversions. */ 1596 exp = decay_conversion (exp); 1597 1598 return exp; 1599} 1600 1601/* EXPR is an expression with an integral or enumeration type. 1602 Perform the integral promotions in [conv.prom], and return the 1603 converted value. */ 1604 1605tree 1606perform_integral_promotions (tree expr) 1607{ 1608 tree type; 1609 tree promoted_type; 1610 1611 /* [conv.prom] 1612 1613 If the bitfield has an enumerated type, it is treated as any 1614 other value of that type for promotion purposes. */ 1615 type = is_bitfield_expr_with_lowered_type (expr); 1616 if (!type || TREE_CODE (type) != ENUMERAL_TYPE) 1617 type = TREE_TYPE (expr); 1618 gcc_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type)); 1619 promoted_type = type_promotes_to (type); 1620 if (type != promoted_type) 1621 expr = cp_convert (promoted_type, expr); 1622 return expr; 1623} 1624 1625/* Take the address of an inline function without setting TREE_ADDRESSABLE 1626 or TREE_USED. */ 1627 1628tree 1629inline_conversion (tree exp) 1630{ 1631 if (TREE_CODE (exp) == FUNCTION_DECL) 1632 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp); 1633 1634 return exp; 1635} 1636 1637/* Returns nonzero iff exp is a STRING_CST or the result of applying 1638 decay_conversion to one. */ 1639 1640int 1641string_conv_p (tree totype, tree exp, int warn) 1642{ 1643 tree t; 1644 1645 if (TREE_CODE (totype) != POINTER_TYPE) 1646 return 0; 1647 1648 t = TREE_TYPE (totype); 1649 if (!same_type_p (t, char_type_node) 1650 && !same_type_p (t, wchar_type_node)) 1651 return 0; 1652 1653 if (TREE_CODE (exp) == STRING_CST) 1654 { 1655 /* Make sure that we don't try to convert between char and wchar_t. */ 1656 if (!same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (exp))), t)) 1657 return 0; 1658 } 1659 else 1660 { 1661 /* Is this a string constant which has decayed to 'const char *'? */ 1662 t = build_pointer_type (build_qualified_type (t, TYPE_QUAL_CONST)); 1663 if (!same_type_p (TREE_TYPE (exp), t)) 1664 return 0; 1665 STRIP_NOPS (exp); 1666 if (TREE_CODE (exp) != ADDR_EXPR 1667 || TREE_CODE (TREE_OPERAND (exp, 0)) != STRING_CST) 1668 return 0; 1669 } 1670 1671 /* This warning is not very useful, as it complains about printf. */ 1672 if (warn) 1673 warning (OPT_Wwrite_strings, 1674 "deprecated conversion from string constant to %qT", 1675 totype); 1676 1677 return 1; 1678} 1679 1680/* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we 1681 can, for example, use as an lvalue. This code used to be in 1682 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c' 1683 expressions, where we're dealing with aggregates. But now it's again only 1684 called from unary_complex_lvalue. The case (in particular) that led to 1685 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd 1686 get it there. */ 1687 1688static tree 1689rationalize_conditional_expr (enum tree_code code, tree t) 1690{ 1691 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that 1692 the first operand is always the one to be used if both operands 1693 are equal, so we know what conditional expression this used to be. */ 1694 if (TREE_CODE (t) == MIN_EXPR || TREE_CODE (t) == MAX_EXPR) 1695 { 1696 tree op0 = TREE_OPERAND (t, 0); 1697 tree op1 = TREE_OPERAND (t, 1); 1698 1699 /* The following code is incorrect if either operand side-effects. */ 1700 gcc_assert (!TREE_SIDE_EFFECTS (op0) 1701 && !TREE_SIDE_EFFECTS (op1)); 1702 return 1703 build_conditional_expr (build_x_binary_op ((TREE_CODE (t) == MIN_EXPR 1704 ? LE_EXPR : GE_EXPR), 1705 op0, TREE_CODE (op0), 1706 op1, TREE_CODE (op1), 1707 /*overloaded_p=*/NULL), 1708 build_unary_op (code, op0, 0), 1709 build_unary_op (code, op1, 0)); 1710 } 1711 1712 return 1713 build_conditional_expr (TREE_OPERAND (t, 0), 1714 build_unary_op (code, TREE_OPERAND (t, 1), 0), 1715 build_unary_op (code, TREE_OPERAND (t, 2), 0)); 1716} 1717 1718/* Given the TYPE of an anonymous union field inside T, return the 1719 FIELD_DECL for the field. If not found return NULL_TREE. Because 1720 anonymous unions can nest, we must also search all anonymous unions 1721 that are directly reachable. */ 1722 1723tree 1724lookup_anon_field (tree t, tree type) 1725{ 1726 tree field; 1727 1728 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field)) 1729 { 1730 if (TREE_STATIC (field)) 1731 continue; 1732 if (TREE_CODE (field) != FIELD_DECL || DECL_ARTIFICIAL (field)) 1733 continue; 1734 1735 /* If we find it directly, return the field. */ 1736 if (DECL_NAME (field) == NULL_TREE 1737 && type == TYPE_MAIN_VARIANT (TREE_TYPE (field))) 1738 { 1739 return field; 1740 } 1741 1742 /* Otherwise, it could be nested, search harder. */ 1743 if (DECL_NAME (field) == NULL_TREE 1744 && ANON_AGGR_TYPE_P (TREE_TYPE (field))) 1745 { 1746 tree subfield = lookup_anon_field (TREE_TYPE (field), type); 1747 if (subfield) 1748 return subfield; 1749 } 1750 } 1751 return NULL_TREE; 1752} 1753 1754/* Build an expression representing OBJECT.MEMBER. OBJECT is an 1755 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is 1756 non-NULL, it indicates the path to the base used to name MEMBER. 1757 If PRESERVE_REFERENCE is true, the expression returned will have 1758 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression 1759 returned will have the type referred to by the reference. 1760 1761 This function does not perform access control; that is either done 1762 earlier by the parser when the name of MEMBER is resolved to MEMBER 1763 itself, or later when overload resolution selects one of the 1764 functions indicated by MEMBER. */ 1765 1766tree 1767build_class_member_access_expr (tree object, tree member, 1768 tree access_path, bool preserve_reference) 1769{ 1770 tree object_type; 1771 tree member_scope; 1772 tree result = NULL_TREE; 1773 1774 if (error_operand_p (object) || error_operand_p (member)) 1775 return error_mark_node; 1776 1777 gcc_assert (DECL_P (member) || BASELINK_P (member)); 1778 1779 /* [expr.ref] 1780 1781 The type of the first expression shall be "class object" (of a 1782 complete type). */ 1783 object_type = TREE_TYPE (object); 1784 if (!currently_open_class (object_type) 1785 && !complete_type_or_else (object_type, object)) 1786 return error_mark_node; 1787 if (!CLASS_TYPE_P (object_type)) 1788 { 1789 error ("request for member %qD in %qE, which is of non-class type %qT", 1790 member, object, object_type); 1791 return error_mark_node; 1792 } 1793 1794 /* The standard does not seem to actually say that MEMBER must be a 1795 member of OBJECT_TYPE. However, that is clearly what is 1796 intended. */ 1797 if (DECL_P (member)) 1798 { 1799 member_scope = DECL_CLASS_CONTEXT (member); 1800 mark_used (member); 1801 if (TREE_DEPRECATED (member)) 1802 warn_deprecated_use (member); 1803 } 1804 else 1805 member_scope = BINFO_TYPE (BASELINK_BINFO (member)); 1806 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will 1807 presently be the anonymous union. Go outwards until we find a 1808 type related to OBJECT_TYPE. */ 1809 while (ANON_AGGR_TYPE_P (member_scope) 1810 && !same_type_ignoring_top_level_qualifiers_p (member_scope, 1811 object_type)) 1812 member_scope = TYPE_CONTEXT (member_scope); 1813 if (!member_scope || !DERIVED_FROM_P (member_scope, object_type)) 1814 { 1815 if (TREE_CODE (member) == FIELD_DECL) 1816 error ("invalid use of nonstatic data member %qE", member); 1817 else 1818 error ("%qD is not a member of %qT", member, object_type); 1819 return error_mark_node; 1820 } 1821 1822 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into 1823 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue 1824 in the frontend; only _DECLs and _REFs are lvalues in the backend. */ 1825 { 1826 tree temp = unary_complex_lvalue (ADDR_EXPR, object); 1827 if (temp) 1828 object = build_indirect_ref (temp, NULL); 1829 } 1830 1831 /* In [expr.ref], there is an explicit list of the valid choices for 1832 MEMBER. We check for each of those cases here. */ 1833 if (TREE_CODE (member) == VAR_DECL) 1834 { 1835 /* A static data member. */ 1836 result = member; 1837 /* If OBJECT has side-effects, they are supposed to occur. */ 1838 if (TREE_SIDE_EFFECTS (object)) 1839 result = build2 (COMPOUND_EXPR, TREE_TYPE (result), object, result); 1840 } 1841 else if (TREE_CODE (member) == FIELD_DECL) 1842 { 1843 /* A non-static data member. */ 1844 bool null_object_p; 1845 int type_quals; 1846 tree member_type; 1847 1848 null_object_p = (TREE_CODE (object) == INDIRECT_REF 1849 && integer_zerop (TREE_OPERAND (object, 0))); 1850 1851 /* Convert OBJECT to the type of MEMBER. */ 1852 if (!same_type_p (TYPE_MAIN_VARIANT (object_type), 1853 TYPE_MAIN_VARIANT (member_scope))) 1854 { 1855 tree binfo; 1856 base_kind kind; 1857 1858 binfo = lookup_base (access_path ? access_path : object_type, 1859 member_scope, ba_unique, &kind); 1860 if (binfo == error_mark_node) 1861 return error_mark_node; 1862 1863 /* It is invalid to try to get to a virtual base of a 1864 NULL object. The most common cause is invalid use of 1865 offsetof macro. */ 1866 if (null_object_p && kind == bk_via_virtual) 1867 { 1868 error ("invalid access to non-static data member %qD of " 1869 "NULL object", 1870 member); 1871 error ("(perhaps the %<offsetof%> macro was used incorrectly)"); 1872 return error_mark_node; 1873 } 1874 1875 /* Convert to the base. */ 1876 object = build_base_path (PLUS_EXPR, object, binfo, 1877 /*nonnull=*/1); 1878 /* If we found the base successfully then we should be able 1879 to convert to it successfully. */ 1880 gcc_assert (object != error_mark_node); 1881 } 1882 1883 /* Complain about other invalid uses of offsetof, even though they will 1884 give the right answer. Note that we complain whether or not they 1885 actually used the offsetof macro, since there's no way to know at this 1886 point. So we just give a warning, instead of a pedwarn. */ 1887 /* Do not produce this warning for base class field references, because 1888 we know for a fact that didn't come from offsetof. This does occur 1889 in various testsuite cases where a null object is passed where a 1890 vtable access is required. */ 1891 if (null_object_p && warn_invalid_offsetof 1892 && CLASSTYPE_NON_POD_P (object_type) 1893 && !DECL_FIELD_IS_BASE (member) 1894 && !skip_evaluation) 1895 { 1896 warning (0, "invalid access to non-static data member %qD of NULL object", 1897 member); 1898 warning (0, "(perhaps the %<offsetof%> macro was used incorrectly)"); 1899 } 1900 1901 /* If MEMBER is from an anonymous aggregate, we have converted 1902 OBJECT so that it refers to the class containing the 1903 anonymous union. Generate a reference to the anonymous union 1904 itself, and recur to find MEMBER. */ 1905 if (ANON_AGGR_TYPE_P (DECL_CONTEXT (member)) 1906 /* When this code is called from build_field_call, the 1907 object already has the type of the anonymous union. 1908 That is because the COMPONENT_REF was already 1909 constructed, and was then disassembled before calling 1910 build_field_call. After the function-call code is 1911 cleaned up, this waste can be eliminated. */ 1912 && (!same_type_ignoring_top_level_qualifiers_p 1913 (TREE_TYPE (object), DECL_CONTEXT (member)))) 1914 { 1915 tree anonymous_union; 1916 1917 anonymous_union = lookup_anon_field (TREE_TYPE (object), 1918 DECL_CONTEXT (member)); 1919 object = build_class_member_access_expr (object, 1920 anonymous_union, 1921 /*access_path=*/NULL_TREE, 1922 preserve_reference); 1923 } 1924 1925 /* Compute the type of the field, as described in [expr.ref]. */ 1926 type_quals = TYPE_UNQUALIFIED; 1927 member_type = TREE_TYPE (member); 1928 if (TREE_CODE (member_type) != REFERENCE_TYPE) 1929 { 1930 type_quals = (cp_type_quals (member_type) 1931 | cp_type_quals (object_type)); 1932 1933 /* A field is const (volatile) if the enclosing object, or the 1934 field itself, is const (volatile). But, a mutable field is 1935 not const, even within a const object. */ 1936 if (DECL_MUTABLE_P (member)) 1937 type_quals &= ~TYPE_QUAL_CONST; 1938 member_type = cp_build_qualified_type (member_type, type_quals); 1939 } 1940 1941 result = build3 (COMPONENT_REF, member_type, object, member, 1942 NULL_TREE); 1943 result = fold_if_not_in_template (result); 1944 1945 /* Mark the expression const or volatile, as appropriate. Even 1946 though we've dealt with the type above, we still have to mark the 1947 expression itself. */ 1948 if (type_quals & TYPE_QUAL_CONST) 1949 TREE_READONLY (result) = 1; 1950 if (type_quals & TYPE_QUAL_VOLATILE) 1951 TREE_THIS_VOLATILE (result) = 1; 1952 } 1953 else if (BASELINK_P (member)) 1954 { 1955 /* The member is a (possibly overloaded) member function. */ 1956 tree functions; 1957 tree type; 1958 1959 /* If the MEMBER is exactly one static member function, then we 1960 know the type of the expression. Otherwise, we must wait 1961 until overload resolution has been performed. */ 1962 functions = BASELINK_FUNCTIONS (member); 1963 if (TREE_CODE (functions) == FUNCTION_DECL 1964 && DECL_STATIC_FUNCTION_P (functions)) 1965 type = TREE_TYPE (functions); 1966 else 1967 type = unknown_type_node; 1968 /* Note that we do not convert OBJECT to the BASELINK_BINFO 1969 base. That will happen when the function is called. */ 1970 result = build3 (COMPONENT_REF, type, object, member, NULL_TREE); 1971 } 1972 else if (TREE_CODE (member) == CONST_DECL) 1973 { 1974 /* The member is an enumerator. */ 1975 result = member; 1976 /* If OBJECT has side-effects, they are supposed to occur. */ 1977 if (TREE_SIDE_EFFECTS (object)) 1978 result = build2 (COMPOUND_EXPR, TREE_TYPE (result), 1979 object, result); 1980 } 1981 else 1982 { 1983 error ("invalid use of %qD", member); 1984 return error_mark_node; 1985 } 1986 1987 if (!preserve_reference) 1988 /* [expr.ref] 1989 1990 If E2 is declared to have type "reference to T", then ... the 1991 type of E1.E2 is T. */ 1992 result = convert_from_reference (result); 1993 1994 return result; 1995} 1996 1997/* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if 1998 SCOPE is NULL, by OBJECT.~DTOR_NAME. */ 1999 2000static tree 2001lookup_destructor (tree object, tree scope, tree dtor_name) 2002{ 2003 tree object_type = TREE_TYPE (object); 2004 tree dtor_type = TREE_OPERAND (dtor_name, 0); 2005 tree expr; 2006 2007 if (scope && !check_dtor_name (scope, dtor_type)) 2008 { 2009 error ("qualified type %qT does not match destructor name ~%qT", 2010 scope, dtor_type); 2011 return error_mark_node; 2012 } 2013 if (!DERIVED_FROM_P (dtor_type, TYPE_MAIN_VARIANT (object_type))) 2014 { 2015 error ("the type being destroyed is %qT, but the destructor refers to %qT", 2016 TYPE_MAIN_VARIANT (object_type), dtor_type); 2017 return error_mark_node; 2018 } 2019 expr = lookup_member (dtor_type, complete_dtor_identifier, 2020 /*protect=*/1, /*want_type=*/false); 2021 expr = (adjust_result_of_qualified_name_lookup 2022 (expr, dtor_type, object_type)); 2023 return expr; 2024} 2025 2026/* An expression of the form "A::template B" has been resolved to 2027 DECL. Issue a diagnostic if B is not a template or template 2028 specialization. */ 2029 2030void 2031check_template_keyword (tree decl) 2032{ 2033 /* The standard says: 2034 2035 [temp.names] 2036 2037 If a name prefixed by the keyword template is not a member 2038 template, the program is ill-formed. 2039 2040 DR 228 removed the restriction that the template be a member 2041 template. 2042 2043 DR 96, if accepted would add the further restriction that explicit 2044 template arguments must be provided if the template keyword is 2045 used, but, as of 2005-10-16, that DR is still in "drafting". If 2046 this DR is accepted, then the semantic checks here can be 2047 simplified, as the entity named must in fact be a template 2048 specialization, rather than, as at present, a set of overloaded 2049 functions containing at least one template function. */ 2050 if (TREE_CODE (decl) != TEMPLATE_DECL 2051 && TREE_CODE (decl) != TEMPLATE_ID_EXPR) 2052 { 2053 if (!is_overloaded_fn (decl)) 2054 pedwarn ("%qD is not a template", decl); 2055 else 2056 { 2057 tree fns; 2058 fns = decl; 2059 if (BASELINK_P (fns)) 2060 fns = BASELINK_FUNCTIONS (fns); 2061 while (fns) 2062 { 2063 tree fn = OVL_CURRENT (fns); 2064 if (TREE_CODE (fn) == TEMPLATE_DECL 2065 || TREE_CODE (fn) == TEMPLATE_ID_EXPR) 2066 break; 2067 if (TREE_CODE (fn) == FUNCTION_DECL 2068 && DECL_USE_TEMPLATE (fn) 2069 && PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (fn))) 2070 break; 2071 fns = OVL_NEXT (fns); 2072 } 2073 if (!fns) 2074 pedwarn ("%qD is not a template", decl); 2075 } 2076 } 2077} 2078 2079/* This function is called by the parser to process a class member 2080 access expression of the form OBJECT.NAME. NAME is a node used by 2081 the parser to represent a name; it is not yet a DECL. It may, 2082 however, be a BASELINK where the BASELINK_FUNCTIONS is a 2083 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and 2084 there is no reason to do the lookup twice, so the parser keeps the 2085 BASELINK. TEMPLATE_P is true iff NAME was explicitly declared to 2086 be a template via the use of the "A::template B" syntax. */ 2087 2088tree 2089finish_class_member_access_expr (tree object, tree name, bool template_p) 2090{ 2091 tree expr; 2092 tree object_type; 2093 tree member; 2094 tree access_path = NULL_TREE; 2095 tree orig_object = object; 2096 tree orig_name = name; 2097 2098 if (object == error_mark_node || name == error_mark_node) 2099 return error_mark_node; 2100 2101 /* If OBJECT is an ObjC class instance, we must obey ObjC access rules. */ 2102 if (!objc_is_public (object, name)) 2103 return error_mark_node; 2104 2105 object_type = TREE_TYPE (object); 2106 2107 if (processing_template_decl) 2108 { 2109 if (/* If OBJECT_TYPE is dependent, so is OBJECT.NAME. */ 2110 dependent_type_p (object_type) 2111 /* If NAME is just an IDENTIFIER_NODE, then the expression 2112 is dependent. */ 2113 || TREE_CODE (object) == IDENTIFIER_NODE 2114 /* If NAME is "f<args>", where either 'f' or 'args' is 2115 dependent, then the expression is dependent. */ 2116 || (TREE_CODE (name) == TEMPLATE_ID_EXPR 2117 && dependent_template_id_p (TREE_OPERAND (name, 0), 2118 TREE_OPERAND (name, 1))) 2119 /* If NAME is "T::X" where "T" is dependent, then the 2120 expression is dependent. */ 2121 || (TREE_CODE (name) == SCOPE_REF 2122 && TYPE_P (TREE_OPERAND (name, 0)) 2123 && dependent_type_p (TREE_OPERAND (name, 0)))) 2124 return build_min_nt (COMPONENT_REF, object, name, NULL_TREE); 2125 object = build_non_dependent_expr (object); 2126 } 2127 2128 /* [expr.ref] 2129 2130 The type of the first expression shall be "class object" (of a 2131 complete type). */ 2132 if (!currently_open_class (object_type) 2133 && !complete_type_or_else (object_type, object)) 2134 return error_mark_node; 2135 if (!CLASS_TYPE_P (object_type)) 2136 { 2137 error ("request for member %qD in %qE, which is of non-class type %qT", 2138 name, object, object_type); 2139 return error_mark_node; 2140 } 2141 2142 if (BASELINK_P (name)) 2143 /* A member function that has already been looked up. */ 2144 member = name; 2145 else 2146 { 2147 bool is_template_id = false; 2148 tree template_args = NULL_TREE; 2149 tree scope; 2150 2151 if (TREE_CODE (name) == TEMPLATE_ID_EXPR) 2152 { 2153 is_template_id = true; 2154 template_args = TREE_OPERAND (name, 1); 2155 name = TREE_OPERAND (name, 0); 2156 2157 if (TREE_CODE (name) == OVERLOAD) 2158 name = DECL_NAME (get_first_fn (name)); 2159 else if (DECL_P (name)) 2160 name = DECL_NAME (name); 2161 } 2162 2163 if (TREE_CODE (name) == SCOPE_REF) 2164 { 2165 /* A qualified name. The qualifying class or namespace `S' 2166 has already been looked up; it is either a TYPE or a 2167 NAMESPACE_DECL. */ 2168 scope = TREE_OPERAND (name, 0); 2169 name = TREE_OPERAND (name, 1); 2170 2171 /* If SCOPE is a namespace, then the qualified name does not 2172 name a member of OBJECT_TYPE. */ 2173 if (TREE_CODE (scope) == NAMESPACE_DECL) 2174 { 2175 error ("%<%D::%D%> is not a member of %qT", 2176 scope, name, object_type); 2177 return error_mark_node; 2178 } 2179 2180 gcc_assert (CLASS_TYPE_P (scope)); 2181 gcc_assert (TREE_CODE (name) == IDENTIFIER_NODE 2182 || TREE_CODE (name) == BIT_NOT_EXPR); 2183 2184 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */ 2185 access_path = lookup_base (object_type, scope, ba_check, NULL); 2186 if (access_path == error_mark_node) 2187 return error_mark_node; 2188 if (!access_path) 2189 { 2190 error ("%qT is not a base of %qT", scope, object_type); 2191 return error_mark_node; 2192 } 2193 } 2194 else 2195 { 2196 scope = NULL_TREE; 2197 access_path = object_type; 2198 } 2199 2200 if (TREE_CODE (name) == BIT_NOT_EXPR) 2201 member = lookup_destructor (object, scope, name); 2202 else 2203 { 2204 /* Look up the member. */ 2205 member = lookup_member (access_path, name, /*protect=*/1, 2206 /*want_type=*/false); 2207 if (member == NULL_TREE) 2208 { 2209 error ("%qD has no member named %qE", object_type, name); 2210 return error_mark_node; 2211 } 2212 if (member == error_mark_node) 2213 return error_mark_node; 2214 } 2215 2216 if (is_template_id) 2217 { 2218 tree template = member; 2219 2220 if (BASELINK_P (template)) 2221 template = lookup_template_function (template, template_args); 2222 else 2223 { 2224 error ("%qD is not a member template function", name); 2225 return error_mark_node; 2226 } 2227 } 2228 } 2229 2230 if (TREE_DEPRECATED (member)) 2231 warn_deprecated_use (member); 2232 2233 if (template_p) 2234 check_template_keyword (member); 2235 2236 expr = build_class_member_access_expr (object, member, access_path, 2237 /*preserve_reference=*/false); 2238 if (processing_template_decl && expr != error_mark_node) 2239 { 2240 if (BASELINK_P (member)) 2241 { 2242 if (TREE_CODE (orig_name) == SCOPE_REF) 2243 BASELINK_QUALIFIED_P (member) = 1; 2244 orig_name = member; 2245 } 2246 return build_min_non_dep (COMPONENT_REF, expr, 2247 orig_object, orig_name, 2248 NULL_TREE); 2249 } 2250 2251 return expr; 2252} 2253 2254/* Return an expression for the MEMBER_NAME field in the internal 2255 representation of PTRMEM, a pointer-to-member function. (Each 2256 pointer-to-member function type gets its own RECORD_TYPE so it is 2257 more convenient to access the fields by name than by FIELD_DECL.) 2258 This routine converts the NAME to a FIELD_DECL and then creates the 2259 node for the complete expression. */ 2260 2261tree 2262build_ptrmemfunc_access_expr (tree ptrmem, tree member_name) 2263{ 2264 tree ptrmem_type; 2265 tree member; 2266 tree member_type; 2267 2268 /* This code is a stripped down version of 2269 build_class_member_access_expr. It does not work to use that 2270 routine directly because it expects the object to be of class 2271 type. */ 2272 ptrmem_type = TREE_TYPE (ptrmem); 2273 gcc_assert (TYPE_PTRMEMFUNC_P (ptrmem_type)); 2274 member = lookup_member (ptrmem_type, member_name, /*protect=*/0, 2275 /*want_type=*/false); 2276 member_type = cp_build_qualified_type (TREE_TYPE (member), 2277 cp_type_quals (ptrmem_type)); 2278 return fold_build3 (COMPONENT_REF, member_type, 2279 ptrmem, member, NULL_TREE); 2280} 2281 2282/* Given an expression PTR for a pointer, return an expression 2283 for the value pointed to. 2284 ERRORSTRING is the name of the operator to appear in error messages. 2285 2286 This function may need to overload OPERATOR_FNNAME. 2287 Must also handle REFERENCE_TYPEs for C++. */ 2288 2289tree 2290build_x_indirect_ref (tree expr, const char *errorstring) 2291{ 2292 tree orig_expr = expr; 2293 tree rval; 2294 2295 if (processing_template_decl) 2296 { 2297 if (type_dependent_expression_p (expr)) 2298 return build_min_nt (INDIRECT_REF, expr); 2299 expr = build_non_dependent_expr (expr); 2300 } 2301 2302 rval = build_new_op (INDIRECT_REF, LOOKUP_NORMAL, expr, NULL_TREE, 2303 NULL_TREE, /*overloaded_p=*/NULL); 2304 if (!rval) 2305 rval = build_indirect_ref (expr, errorstring); 2306 2307 if (processing_template_decl && rval != error_mark_node) 2308 return build_min_non_dep (INDIRECT_REF, rval, orig_expr); 2309 else 2310 return rval; 2311} 2312 2313tree 2314build_indirect_ref (tree ptr, const char *errorstring) 2315{ 2316 tree pointer, type; 2317 2318 if (ptr == error_mark_node) 2319 return error_mark_node; 2320 2321 if (ptr == current_class_ptr) 2322 return current_class_ref; 2323 2324 pointer = (TREE_CODE (TREE_TYPE (ptr)) == REFERENCE_TYPE 2325 ? ptr : decay_conversion (ptr)); 2326 type = TREE_TYPE (pointer); 2327 2328 if (POINTER_TYPE_P (type)) 2329 { 2330 /* [expr.unary.op] 2331 2332 If the type of the expression is "pointer to T," the type 2333 of the result is "T." 2334 2335 We must use the canonical variant because certain parts of 2336 the back end, like fold, do pointer comparisons between 2337 types. */ 2338 tree t = canonical_type_variant (TREE_TYPE (type)); 2339 2340 if (TREE_CODE (ptr) == CONVERT_EXPR 2341 || TREE_CODE (ptr) == NOP_EXPR 2342 || TREE_CODE (ptr) == VIEW_CONVERT_EXPR) 2343 { 2344 /* If a warning is issued, mark it to avoid duplicates from 2345 the backend. This only needs to be done at 2346 warn_strict_aliasing > 2. */ 2347 if (warn_strict_aliasing > 2) 2348 if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (ptr, 0)), 2349 type, TREE_OPERAND (ptr, 0))) 2350 TREE_NO_WARNING (ptr) = 1; 2351 } 2352 2353 if (VOID_TYPE_P (t)) 2354 { 2355 /* A pointer to incomplete type (other than cv void) can be 2356 dereferenced [expr.unary.op]/1 */ 2357 error ("%qT is not a pointer-to-object type", type); 2358 return error_mark_node; 2359 } 2360 else if (TREE_CODE (pointer) == ADDR_EXPR 2361 && same_type_p (t, TREE_TYPE (TREE_OPERAND (pointer, 0)))) 2362 /* The POINTER was something like `&x'. We simplify `*&x' to 2363 `x'. */ 2364 return TREE_OPERAND (pointer, 0); 2365 else 2366 { 2367 tree ref = build1 (INDIRECT_REF, t, pointer); 2368 2369 /* We *must* set TREE_READONLY when dereferencing a pointer to const, 2370 so that we get the proper error message if the result is used 2371 to assign to. Also, &* is supposed to be a no-op. */ 2372 TREE_READONLY (ref) = CP_TYPE_CONST_P (t); 2373 TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); 2374 TREE_SIDE_EFFECTS (ref) 2375 = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (pointer)); 2376 return ref; 2377 } 2378 } 2379 /* `pointer' won't be an error_mark_node if we were given a 2380 pointer to member, so it's cool to check for this here. */ 2381 else if (TYPE_PTR_TO_MEMBER_P (type)) 2382 error ("invalid use of %qs on pointer to member", errorstring); 2383 else if (pointer != error_mark_node) 2384 { 2385 if (errorstring) 2386 error ("invalid type argument of %qs", errorstring); 2387 else 2388 error ("invalid type argument"); 2389 } 2390 return error_mark_node; 2391} 2392 2393/* This handles expressions of the form "a[i]", which denotes 2394 an array reference. 2395 2396 This is logically equivalent in C to *(a+i), but we may do it differently. 2397 If A is a variable or a member, we generate a primitive ARRAY_REF. 2398 This avoids forcing the array out of registers, and can work on 2399 arrays that are not lvalues (for example, members of structures returned 2400 by functions). 2401 2402 If INDEX is of some user-defined type, it must be converted to 2403 integer type. Otherwise, to make a compatible PLUS_EXPR, it 2404 will inherit the type of the array, which will be some pointer type. */ 2405 2406tree 2407build_array_ref (tree array, tree idx) 2408{ 2409 if (idx == 0) 2410 { 2411 error ("subscript missing in array reference"); 2412 return error_mark_node; 2413 } 2414 2415 if (TREE_TYPE (array) == error_mark_node 2416 || TREE_TYPE (idx) == error_mark_node) 2417 return error_mark_node; 2418 2419 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference 2420 inside it. */ 2421 switch (TREE_CODE (array)) 2422 { 2423 case COMPOUND_EXPR: 2424 { 2425 tree value = build_array_ref (TREE_OPERAND (array, 1), idx); 2426 return build2 (COMPOUND_EXPR, TREE_TYPE (value), 2427 TREE_OPERAND (array, 0), value); 2428 } 2429 2430 case COND_EXPR: 2431 return build_conditional_expr 2432 (TREE_OPERAND (array, 0), 2433 build_array_ref (TREE_OPERAND (array, 1), idx), 2434 build_array_ref (TREE_OPERAND (array, 2), idx)); 2435 2436 default: 2437 break; 2438 } 2439 2440 if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE) 2441 { 2442 tree rval, type; 2443 2444 warn_array_subscript_with_type_char (idx); 2445 2446 if (!INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (idx))) 2447 { 2448 error ("array subscript is not an integer"); 2449 return error_mark_node; 2450 } 2451 2452 /* Apply integral promotions *after* noticing character types. 2453 (It is unclear why we do these promotions -- the standard 2454 does not say that we should. In fact, the natural thing would 2455 seem to be to convert IDX to ptrdiff_t; we're performing 2456 pointer arithmetic.) */ 2457 idx = perform_integral_promotions (idx); 2458 2459 /* An array that is indexed by a non-constant 2460 cannot be stored in a register; we must be able to do 2461 address arithmetic on its address. 2462 Likewise an array of elements of variable size. */ 2463 if (TREE_CODE (idx) != INTEGER_CST 2464 || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array))) 2465 && (TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) 2466 != INTEGER_CST))) 2467 { 2468 if (!cxx_mark_addressable (array)) 2469 return error_mark_node; 2470 } 2471 2472 /* An array that is indexed by a constant value which is not within 2473 the array bounds cannot be stored in a register either; because we 2474 would get a crash in store_bit_field/extract_bit_field when trying 2475 to access a non-existent part of the register. */ 2476 if (TREE_CODE (idx) == INTEGER_CST 2477 && TYPE_DOMAIN (TREE_TYPE (array)) 2478 && ! int_fits_type_p (idx, TYPE_DOMAIN (TREE_TYPE (array)))) 2479 { 2480 if (!cxx_mark_addressable (array)) 2481 return error_mark_node; 2482 } 2483 2484 if (pedantic && !lvalue_p (array)) 2485 pedwarn ("ISO C++ forbids subscripting non-lvalue array"); 2486 2487 /* Note in C++ it is valid to subscript a `register' array, since 2488 it is valid to take the address of something with that 2489 storage specification. */ 2490 if (extra_warnings) 2491 { 2492 tree foo = array; 2493 while (TREE_CODE (foo) == COMPONENT_REF) 2494 foo = TREE_OPERAND (foo, 0); 2495 if (TREE_CODE (foo) == VAR_DECL && DECL_REGISTER (foo)) 2496 warning (OPT_Wextra, "subscripting array declared %<register%>"); 2497 } 2498 2499 type = TREE_TYPE (TREE_TYPE (array)); 2500 rval = build4 (ARRAY_REF, type, array, idx, NULL_TREE, NULL_TREE); 2501 /* Array ref is const/volatile if the array elements are 2502 or if the array is.. */ 2503 TREE_READONLY (rval) 2504 |= (CP_TYPE_CONST_P (type) | TREE_READONLY (array)); 2505 TREE_SIDE_EFFECTS (rval) 2506 |= (CP_TYPE_VOLATILE_P (type) | TREE_SIDE_EFFECTS (array)); 2507 TREE_THIS_VOLATILE (rval) 2508 |= (CP_TYPE_VOLATILE_P (type) | TREE_THIS_VOLATILE (array)); 2509 return require_complete_type (fold_if_not_in_template (rval)); 2510 } 2511 2512 { 2513 tree ar = default_conversion (array); 2514 tree ind = default_conversion (idx); 2515 2516 /* Put the integer in IND to simplify error checking. */ 2517 if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE) 2518 { 2519 tree temp = ar; 2520 ar = ind; 2521 ind = temp; 2522 } 2523 2524 if (ar == error_mark_node) 2525 return ar; 2526 2527 if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE) 2528 { 2529 error ("subscripted value is neither array nor pointer"); 2530 return error_mark_node; 2531 } 2532 if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE) 2533 { 2534 error ("array subscript is not an integer"); 2535 return error_mark_node; 2536 } 2537 2538 return build_indirect_ref (cp_build_binary_op (PLUS_EXPR, ar, ind), 2539 "array indexing"); 2540 } 2541} 2542 2543/* Resolve a pointer to member function. INSTANCE is the object 2544 instance to use, if the member points to a virtual member. 2545 2546 This used to avoid checking for virtual functions if basetype 2547 has no virtual functions, according to an earlier ANSI draft. 2548 With the final ISO C++ rules, such an optimization is 2549 incorrect: A pointer to a derived member can be static_cast 2550 to pointer-to-base-member, as long as the dynamic object 2551 later has the right member. */ 2552 2553tree 2554get_member_function_from_ptrfunc (tree *instance_ptrptr, tree function) 2555{ 2556 if (TREE_CODE (function) == OFFSET_REF) 2557 function = TREE_OPERAND (function, 1); 2558 2559 if (TYPE_PTRMEMFUNC_P (TREE_TYPE (function))) 2560 { 2561 tree idx, delta, e1, e2, e3, vtbl, basetype; 2562 tree fntype = TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (function)); 2563 2564 tree instance_ptr = *instance_ptrptr; 2565 tree instance_save_expr = 0; 2566 if (instance_ptr == error_mark_node) 2567 { 2568 if (TREE_CODE (function) == PTRMEM_CST) 2569 { 2570 /* Extracting the function address from a pmf is only 2571 allowed with -Wno-pmf-conversions. It only works for 2572 pmf constants. */ 2573 e1 = build_addr_func (PTRMEM_CST_MEMBER (function)); 2574 e1 = convert (fntype, e1); 2575 return e1; 2576 } 2577 else 2578 { 2579 error ("object missing in use of %qE", function); 2580 return error_mark_node; 2581 } 2582 } 2583 2584 if (TREE_SIDE_EFFECTS (instance_ptr)) 2585 instance_ptr = instance_save_expr = save_expr (instance_ptr); 2586 2587 if (TREE_SIDE_EFFECTS (function)) 2588 function = save_expr (function); 2589 2590 /* Start by extracting all the information from the PMF itself. */ 2591 e3 = pfn_from_ptrmemfunc (function); 2592 delta = build_ptrmemfunc_access_expr (function, delta_identifier); 2593 idx = build1 (NOP_EXPR, vtable_index_type, e3); 2594 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION) 2595 { 2596 case ptrmemfunc_vbit_in_pfn: 2597 e1 = cp_build_binary_op (BIT_AND_EXPR, idx, integer_one_node); 2598 idx = cp_build_binary_op (MINUS_EXPR, idx, integer_one_node); 2599 break; 2600 2601 case ptrmemfunc_vbit_in_delta: 2602 e1 = cp_build_binary_op (BIT_AND_EXPR, delta, integer_one_node); 2603 delta = cp_build_binary_op (RSHIFT_EXPR, delta, integer_one_node); 2604 break; 2605 2606 default: 2607 gcc_unreachable (); 2608 } 2609 2610 /* Convert down to the right base before using the instance. A 2611 special case is that in a pointer to member of class C, C may 2612 be incomplete. In that case, the function will of course be 2613 a member of C, and no conversion is required. In fact, 2614 lookup_base will fail in that case, because incomplete 2615 classes do not have BINFOs. */ 2616 basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (fntype)); 2617 if (!same_type_ignoring_top_level_qualifiers_p 2618 (basetype, TREE_TYPE (TREE_TYPE (instance_ptr)))) 2619 { 2620 basetype = lookup_base (TREE_TYPE (TREE_TYPE (instance_ptr)), 2621 basetype, ba_check, NULL); 2622 instance_ptr = build_base_path (PLUS_EXPR, instance_ptr, basetype, 2623 1); 2624 if (instance_ptr == error_mark_node) 2625 return error_mark_node; 2626 } 2627 /* ...and then the delta in the PMF. */ 2628 instance_ptr = build2 (PLUS_EXPR, TREE_TYPE (instance_ptr), 2629 instance_ptr, delta); 2630 2631 /* Hand back the adjusted 'this' argument to our caller. */ 2632 *instance_ptrptr = instance_ptr; 2633 2634 /* Next extract the vtable pointer from the object. */ 2635 vtbl = build1 (NOP_EXPR, build_pointer_type (vtbl_ptr_type_node), 2636 instance_ptr); 2637 vtbl = build_indirect_ref (vtbl, NULL); 2638 2639 /* Finally, extract the function pointer from the vtable. */ 2640 e2 = fold_build2 (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, idx); 2641 e2 = build_indirect_ref (e2, NULL); 2642 TREE_CONSTANT (e2) = 1; 2643 TREE_INVARIANT (e2) = 1; 2644 2645 /* When using function descriptors, the address of the 2646 vtable entry is treated as a function pointer. */ 2647 if (TARGET_VTABLE_USES_DESCRIPTORS) 2648 e2 = build1 (NOP_EXPR, TREE_TYPE (e2), 2649 build_unary_op (ADDR_EXPR, e2, /*noconvert=*/1)); 2650 2651 TREE_TYPE (e2) = TREE_TYPE (e3); 2652 e1 = build_conditional_expr (e1, e2, e3); 2653 2654 /* Make sure this doesn't get evaluated first inside one of the 2655 branches of the COND_EXPR. */ 2656 if (instance_save_expr) 2657 e1 = build2 (COMPOUND_EXPR, TREE_TYPE (e1), 2658 instance_save_expr, e1); 2659 2660 function = e1; 2661 } 2662 return function; 2663} 2664 2665tree 2666build_function_call (tree function, tree params) 2667{ 2668 tree fntype, fndecl; 2669 tree coerced_params; 2670 tree name = NULL_TREE; 2671 int is_method; 2672 tree original = function; 2673 2674 /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF 2675 expressions, like those used for ObjC messenger dispatches. */ 2676 function = objc_rewrite_function_call (function, params); 2677 2678 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 2679 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */ 2680 if (TREE_CODE (function) == NOP_EXPR 2681 && TREE_TYPE (function) == TREE_TYPE (TREE_OPERAND (function, 0))) 2682 function = TREE_OPERAND (function, 0); 2683 2684 if (TREE_CODE (function) == FUNCTION_DECL) 2685 { 2686 name = DECL_NAME (function); 2687 2688 mark_used (function); 2689 fndecl = function; 2690 2691 /* Convert anything with function type to a pointer-to-function. */ 2692 if (pedantic && DECL_MAIN_P (function)) 2693 pedwarn ("ISO C++ forbids calling %<::main%> from within program"); 2694 2695 /* Differs from default_conversion by not setting TREE_ADDRESSABLE 2696 (because calling an inline function does not mean the function 2697 needs to be separately compiled). */ 2698 2699 if (DECL_INLINE (function)) 2700 function = inline_conversion (function); 2701 else 2702 function = build_addr_func (function); 2703 } 2704 else 2705 { 2706 fndecl = NULL_TREE; 2707 2708 function = build_addr_func (function); 2709 } 2710 2711 if (function == error_mark_node) 2712 return error_mark_node; 2713 2714 fntype = TREE_TYPE (function); 2715 2716 if (TYPE_PTRMEMFUNC_P (fntype)) 2717 { 2718 error ("must use %<.*%> or %<->*%> to call pointer-to-member " 2719 "function in %<%E (...)%>", 2720 original); 2721 return error_mark_node; 2722 } 2723 2724 is_method = (TREE_CODE (fntype) == POINTER_TYPE 2725 && TREE_CODE (TREE_TYPE (fntype)) == METHOD_TYPE); 2726 2727 if (!((TREE_CODE (fntype) == POINTER_TYPE 2728 && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE) 2729 || is_method 2730 || TREE_CODE (function) == TEMPLATE_ID_EXPR)) 2731 { 2732 error ("%qE cannot be used as a function", original); 2733 return error_mark_node; 2734 } 2735 2736 /* fntype now gets the type of function pointed to. */ 2737 fntype = TREE_TYPE (fntype); 2738 2739 /* Convert the parameters to the types declared in the 2740 function prototype, or apply default promotions. */ 2741 2742 coerced_params = convert_arguments (TYPE_ARG_TYPES (fntype), 2743 params, fndecl, LOOKUP_NORMAL); 2744 if (coerced_params == error_mark_node) 2745 return error_mark_node; 2746 2747 /* Check for errors in format strings and inappropriately 2748 null parameters. */ 2749 2750 check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params, 2751 TYPE_ARG_TYPES (fntype)); 2752 2753 return build_cxx_call (function, coerced_params); 2754} 2755 2756/* Convert the actual parameter expressions in the list VALUES 2757 to the types in the list TYPELIST. 2758 If parmdecls is exhausted, or when an element has NULL as its type, 2759 perform the default conversions. 2760 2761 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages. 2762 2763 This is also where warnings about wrong number of args are generated. 2764 2765 Return a list of expressions for the parameters as converted. 2766 2767 Both VALUES and the returned value are chains of TREE_LIST nodes 2768 with the elements of the list in the TREE_VALUE slots of those nodes. 2769 2770 In C++, unspecified trailing parameters can be filled in with their 2771 default arguments, if such were specified. Do so here. */ 2772 2773static tree 2774convert_arguments (tree typelist, tree values, tree fndecl, int flags) 2775{ 2776 tree typetail, valtail; 2777 tree result = NULL_TREE; 2778 const char *called_thing = 0; 2779 int i = 0; 2780 2781 /* Argument passing is always copy-initialization. */ 2782 flags |= LOOKUP_ONLYCONVERTING; 2783 2784 if (fndecl) 2785 { 2786 if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE) 2787 { 2788 if (DECL_NAME (fndecl) == NULL_TREE 2789 || IDENTIFIER_HAS_TYPE_VALUE (DECL_NAME (fndecl))) 2790 called_thing = "constructor"; 2791 else 2792 called_thing = "member function"; 2793 } 2794 else 2795 called_thing = "function"; 2796 } 2797 2798 for (valtail = values, typetail = typelist; 2799 valtail; 2800 valtail = TREE_CHAIN (valtail), i++) 2801 { 2802 tree type = typetail ? TREE_VALUE (typetail) : 0; 2803 tree val = TREE_VALUE (valtail); 2804 2805 if (val == error_mark_node || type == error_mark_node) 2806 return error_mark_node; 2807 2808 if (type == void_type_node) 2809 { 2810 if (fndecl) 2811 { 2812 error ("too many arguments to %s %q+#D", called_thing, fndecl); 2813 error ("at this point in file"); 2814 } 2815 else 2816 error ("too many arguments to function"); 2817 /* In case anybody wants to know if this argument 2818 list is valid. */ 2819 if (result) 2820 TREE_TYPE (tree_last (result)) = error_mark_node; 2821 break; 2822 } 2823 2824 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 2825 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */ 2826 if (TREE_CODE (val) == NOP_EXPR 2827 && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)) 2828 && (type == 0 || TREE_CODE (type) != REFERENCE_TYPE)) 2829 val = TREE_OPERAND (val, 0); 2830 2831 if (type == 0 || TREE_CODE (type) != REFERENCE_TYPE) 2832 { 2833 if (TREE_CODE (TREE_TYPE (val)) == ARRAY_TYPE 2834 || TREE_CODE (TREE_TYPE (val)) == FUNCTION_TYPE 2835 || TREE_CODE (TREE_TYPE (val)) == METHOD_TYPE) 2836 val = decay_conversion (val); 2837 } 2838 2839 if (val == error_mark_node) 2840 return error_mark_node; 2841 2842 if (type != 0) 2843 { 2844 /* Formal parm type is specified by a function prototype. */ 2845 tree parmval; 2846 2847 if (!COMPLETE_TYPE_P (complete_type (type))) 2848 { 2849 if (fndecl) 2850 error ("parameter %P of %qD has incomplete type %qT", 2851 i, fndecl, type); 2852 else 2853 error ("parameter %P has incomplete type %qT", i, type); 2854 parmval = error_mark_node; 2855 } 2856 else 2857 { 2858 parmval = convert_for_initialization 2859 (NULL_TREE, type, val, flags, 2860 "argument passing", fndecl, i); 2861 parmval = convert_for_arg_passing (type, parmval); 2862 } 2863 2864 if (parmval == error_mark_node) 2865 return error_mark_node; 2866 2867 result = tree_cons (NULL_TREE, parmval, result); 2868 } 2869 else 2870 { 2871 if (fndecl && DECL_BUILT_IN (fndecl) 2872 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P) 2873 /* Don't do ellipsis conversion for __built_in_constant_p 2874 as this will result in spurious warnings for non-POD 2875 types. */ 2876 val = require_complete_type (val); 2877 else 2878 val = convert_arg_to_ellipsis (val); 2879 2880 result = tree_cons (NULL_TREE, val, result); 2881 } 2882 2883 if (typetail) 2884 typetail = TREE_CHAIN (typetail); 2885 } 2886 2887 if (typetail != 0 && typetail != void_list_node) 2888 { 2889 /* See if there are default arguments that can be used. */ 2890 if (TREE_PURPOSE (typetail) 2891 && TREE_CODE (TREE_PURPOSE (typetail)) != DEFAULT_ARG) 2892 { 2893 for (; typetail != void_list_node; ++i) 2894 { 2895 tree parmval 2896 = convert_default_arg (TREE_VALUE (typetail), 2897 TREE_PURPOSE (typetail), 2898 fndecl, i); 2899 2900 if (parmval == error_mark_node) 2901 return error_mark_node; 2902 2903 result = tree_cons (0, parmval, result); 2904 typetail = TREE_CHAIN (typetail); 2905 /* ends with `...'. */ 2906 if (typetail == NULL_TREE) 2907 break; 2908 } 2909 } 2910 else 2911 { 2912 if (fndecl) 2913 { 2914 error ("too few arguments to %s %q+#D", called_thing, fndecl); 2915 error ("at this point in file"); 2916 } 2917 else 2918 error ("too few arguments to function"); 2919 return error_mark_node; 2920 } 2921 } 2922 2923 return nreverse (result); 2924} 2925 2926/* Build a binary-operation expression, after performing default 2927 conversions on the operands. CODE is the kind of expression to build. */ 2928 2929tree 2930build_x_binary_op (enum tree_code code, tree arg1, enum tree_code arg1_code, 2931 tree arg2, enum tree_code arg2_code, bool *overloaded_p) 2932{ 2933 tree orig_arg1; 2934 tree orig_arg2; 2935 tree expr; 2936 2937 orig_arg1 = arg1; 2938 orig_arg2 = arg2; 2939 2940 if (processing_template_decl) 2941 { 2942 if (type_dependent_expression_p (arg1) 2943 || type_dependent_expression_p (arg2)) 2944 return build_min_nt (code, arg1, arg2); 2945 arg1 = build_non_dependent_expr (arg1); 2946 arg2 = build_non_dependent_expr (arg2); 2947 } 2948 2949 if (code == DOTSTAR_EXPR) 2950 expr = build_m_component_ref (arg1, arg2); 2951 else 2952 expr = build_new_op (code, LOOKUP_NORMAL, arg1, arg2, NULL_TREE, 2953 overloaded_p); 2954 2955 /* Check for cases such as x+y<<z which users are likely to 2956 misinterpret. But don't warn about obj << x + y, since that is a 2957 common idiom for I/O. */ 2958 if (warn_parentheses 2959 && !processing_template_decl 2960 && !error_operand_p (arg1) 2961 && !error_operand_p (arg2) 2962 && (code != LSHIFT_EXPR 2963 || !IS_AGGR_TYPE (TREE_TYPE (arg1)))) 2964 warn_about_parentheses (code, arg1_code, arg2_code); 2965 2966 if (processing_template_decl && expr != error_mark_node) 2967 return build_min_non_dep (code, expr, orig_arg1, orig_arg2); 2968 2969 return expr; 2970} 2971 2972/* Build a binary-operation expression without default conversions. 2973 CODE is the kind of expression to build. 2974 This function differs from `build' in several ways: 2975 the data type of the result is computed and recorded in it, 2976 warnings are generated if arg data types are invalid, 2977 special handling for addition and subtraction of pointers is known, 2978 and some optimization is done (operations on narrow ints 2979 are done in the narrower type when that gives the same result). 2980 Constant folding is also done before the result is returned. 2981 2982 Note that the operands will never have enumeral types 2983 because either they have just had the default conversions performed 2984 or they have both just been converted to some other type in which 2985 the arithmetic is to be done. 2986 2987 C++: must do special pointer arithmetic when implementing 2988 multiple inheritance, and deal with pointer to member functions. */ 2989 2990tree 2991build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1, 2992 int convert_p ATTRIBUTE_UNUSED) 2993{ 2994 tree op0, op1; 2995 enum tree_code code0, code1; 2996 tree type0, type1; 2997 const char *invalid_op_diag; 2998 2999 /* Expression code to give to the expression when it is built. 3000 Normally this is CODE, which is what the caller asked for, 3001 but in some special cases we change it. */ 3002 enum tree_code resultcode = code; 3003 3004 /* Data type in which the computation is to be performed. 3005 In the simplest cases this is the common type of the arguments. */ 3006 tree result_type = NULL; 3007 3008 /* Nonzero means operands have already been type-converted 3009 in whatever way is necessary. 3010 Zero means they need to be converted to RESULT_TYPE. */ 3011 int converted = 0; 3012 3013 /* Nonzero means create the expression with this type, rather than 3014 RESULT_TYPE. */ 3015 tree build_type = 0; 3016 3017 /* Nonzero means after finally constructing the expression 3018 convert it to this type. */ 3019 tree final_type = 0; 3020 3021 tree result; 3022 3023 /* Nonzero if this is an operation like MIN or MAX which can 3024 safely be computed in short if both args are promoted shorts. 3025 Also implies COMMON. 3026 -1 indicates a bitwise operation; this makes a difference 3027 in the exact conditions for when it is safe to do the operation 3028 in a narrower mode. */ 3029 int shorten = 0; 3030 3031 /* Nonzero if this is a comparison operation; 3032 if both args are promoted shorts, compare the original shorts. 3033 Also implies COMMON. */ 3034 int short_compare = 0; 3035 3036 /* Nonzero if this is a right-shift operation, which can be computed on the 3037 original short and then promoted if the operand is a promoted short. */ 3038 int short_shift = 0; 3039 3040 /* Nonzero means set RESULT_TYPE to the common type of the args. */ 3041 int common = 0; 3042 3043 /* True if both operands have arithmetic type. */ 3044 bool arithmetic_types_p; 3045 3046 /* Apply default conversions. */ 3047 op0 = orig_op0; 3048 op1 = orig_op1; 3049 3050 if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR 3051 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR 3052 || code == TRUTH_XOR_EXPR) 3053 { 3054 if (!really_overloaded_fn (op0)) 3055 op0 = decay_conversion (op0); 3056 if (!really_overloaded_fn (op1)) 3057 op1 = decay_conversion (op1); 3058 } 3059 else 3060 { 3061 if (!really_overloaded_fn (op0)) 3062 op0 = default_conversion (op0); 3063 if (!really_overloaded_fn (op1)) 3064 op1 = default_conversion (op1); 3065 } 3066 3067 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */ 3068 STRIP_TYPE_NOPS (op0); 3069 STRIP_TYPE_NOPS (op1); 3070 3071 /* DTRT if one side is an overloaded function, but complain about it. */ 3072 if (type_unknown_p (op0)) 3073 { 3074 tree t = instantiate_type (TREE_TYPE (op1), op0, tf_none); 3075 if (t != error_mark_node) 3076 { 3077 pedwarn ("assuming cast to type %qT from overloaded function", 3078 TREE_TYPE (t)); 3079 op0 = t; 3080 } 3081 } 3082 if (type_unknown_p (op1)) 3083 { 3084 tree t = instantiate_type (TREE_TYPE (op0), op1, tf_none); 3085 if (t != error_mark_node) 3086 { 3087 pedwarn ("assuming cast to type %qT from overloaded function", 3088 TREE_TYPE (t)); 3089 op1 = t; 3090 } 3091 } 3092 3093 type0 = TREE_TYPE (op0); 3094 type1 = TREE_TYPE (op1); 3095 3096 /* The expression codes of the data types of the arguments tell us 3097 whether the arguments are integers, floating, pointers, etc. */ 3098 code0 = TREE_CODE (type0); 3099 code1 = TREE_CODE (type1); 3100 3101 /* If an error was already reported for one of the arguments, 3102 avoid reporting another error. */ 3103 3104 if (code0 == ERROR_MARK || code1 == ERROR_MARK) 3105 return error_mark_node; 3106 3107 if ((invalid_op_diag 3108 = targetm.invalid_binary_op (code, type0, type1))) 3109 { 3110 error (invalid_op_diag); 3111 return error_mark_node; 3112 } 3113 3114 switch (code) 3115 { 3116 case MINUS_EXPR: 3117 /* Subtraction of two similar pointers. 3118 We must subtract them as integers, then divide by object size. */ 3119 if (code0 == POINTER_TYPE && code1 == POINTER_TYPE 3120 && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (type0), 3121 TREE_TYPE (type1))) 3122 return pointer_diff (op0, op1, common_type (type0, type1)); 3123 /* In all other cases except pointer - int, the usual arithmetic 3124 rules aply. */ 3125 else if (!(code0 == POINTER_TYPE && code1 == INTEGER_TYPE)) 3126 { 3127 common = 1; 3128 break; 3129 } 3130 /* The pointer - int case is just like pointer + int; fall 3131 through. */ 3132 case PLUS_EXPR: 3133 if ((code0 == POINTER_TYPE || code1 == POINTER_TYPE) 3134 && (code0 == INTEGER_TYPE || code1 == INTEGER_TYPE)) 3135 { 3136 tree ptr_operand; 3137 tree int_operand; 3138 ptr_operand = ((code0 == POINTER_TYPE) ? op0 : op1); 3139 int_operand = ((code0 == INTEGER_TYPE) ? op0 : op1); 3140 if (processing_template_decl) 3141 { 3142 result_type = TREE_TYPE (ptr_operand); 3143 break; 3144 } 3145 return cp_pointer_int_sum (code, 3146 ptr_operand, 3147 int_operand); 3148 } 3149 common = 1; 3150 break; 3151 3152 case MULT_EXPR: 3153 common = 1; 3154 break; 3155 3156 case TRUNC_DIV_EXPR: 3157 case CEIL_DIV_EXPR: 3158 case FLOOR_DIV_EXPR: 3159 case ROUND_DIV_EXPR: 3160 case EXACT_DIV_EXPR: 3161 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE 3162 || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE) 3163 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 3164 || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)) 3165 { 3166 enum tree_code tcode0 = code0, tcode1 = code1; 3167 3168 if (TREE_CODE (op1) == INTEGER_CST && integer_zerop (op1)) 3169 warning (OPT_Wdiv_by_zero, "division by zero in %<%E / 0%>", op0); 3170 else if (TREE_CODE (op1) == REAL_CST && real_zerop (op1)) 3171 warning (OPT_Wdiv_by_zero, "division by zero in %<%E / 0.%>", op0); 3172 3173 if (tcode0 == COMPLEX_TYPE || tcode0 == VECTOR_TYPE) 3174 tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0))); 3175 if (tcode1 == COMPLEX_TYPE || tcode1 == VECTOR_TYPE) 3176 tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1))); 3177 3178 if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)) 3179 resultcode = RDIV_EXPR; 3180 else 3181 /* When dividing two signed integers, we have to promote to int. 3182 unless we divide by a constant != -1. Note that default 3183 conversion will have been performed on the operands at this 3184 point, so we have to dig out the original type to find out if 3185 it was unsigned. */ 3186 shorten = ((TREE_CODE (op0) == NOP_EXPR 3187 && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0)))) 3188 || (TREE_CODE (op1) == INTEGER_CST 3189 && ! integer_all_onesp (op1))); 3190 3191 common = 1; 3192 } 3193 break; 3194 3195 case BIT_AND_EXPR: 3196 case BIT_IOR_EXPR: 3197 case BIT_XOR_EXPR: 3198 if ((code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3199 || (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)) 3200 shorten = -1; 3201 break; 3202 3203 case TRUNC_MOD_EXPR: 3204 case FLOOR_MOD_EXPR: 3205 if (code1 == INTEGER_TYPE && integer_zerop (op1)) 3206 warning (OPT_Wdiv_by_zero, "division by zero in %<%E %% 0%>", op0); 3207 else if (code1 == REAL_TYPE && real_zerop (op1)) 3208 warning (OPT_Wdiv_by_zero, "division by zero in %<%E %% 0.%>", op0); 3209 3210 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3211 { 3212 /* Although it would be tempting to shorten always here, that loses 3213 on some targets, since the modulo instruction is undefined if the 3214 quotient can't be represented in the computation mode. We shorten 3215 only if unsigned or if dividing by something we know != -1. */ 3216 shorten = ((TREE_CODE (op0) == NOP_EXPR 3217 && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0)))) 3218 || (TREE_CODE (op1) == INTEGER_CST 3219 && ! integer_all_onesp (op1))); 3220 common = 1; 3221 } 3222 break; 3223 3224 case TRUTH_ANDIF_EXPR: 3225 case TRUTH_ORIF_EXPR: 3226 case TRUTH_AND_EXPR: 3227 case TRUTH_OR_EXPR: 3228 result_type = boolean_type_node; 3229 break; 3230 3231 /* Shift operations: result has same type as first operand; 3232 always convert second operand to int. 3233 Also set SHORT_SHIFT if shifting rightward. */ 3234 3235 case RSHIFT_EXPR: 3236 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3237 { 3238 result_type = type0; 3239 if (TREE_CODE (op1) == INTEGER_CST) 3240 { 3241 if (tree_int_cst_lt (op1, integer_zero_node)) 3242 warning (0, "right shift count is negative"); 3243 else 3244 { 3245 if (! integer_zerop (op1)) 3246 short_shift = 1; 3247 if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 3248 warning (0, "right shift count >= width of type"); 3249 } 3250 } 3251 /* Convert the shift-count to an integer, regardless of 3252 size of value being shifted. */ 3253 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 3254 op1 = cp_convert (integer_type_node, op1); 3255 /* Avoid converting op1 to result_type later. */ 3256 converted = 1; 3257 } 3258 break; 3259 3260 case LSHIFT_EXPR: 3261 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3262 { 3263 result_type = type0; 3264 if (TREE_CODE (op1) == INTEGER_CST) 3265 { 3266 if (tree_int_cst_lt (op1, integer_zero_node)) 3267 warning (0, "left shift count is negative"); 3268 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 3269 warning (0, "left shift count >= width of type"); 3270 } 3271 /* Convert the shift-count to an integer, regardless of 3272 size of value being shifted. */ 3273 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 3274 op1 = cp_convert (integer_type_node, op1); 3275 /* Avoid converting op1 to result_type later. */ 3276 converted = 1; 3277 } 3278 break; 3279 3280 case RROTATE_EXPR: 3281 case LROTATE_EXPR: 3282 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3283 { 3284 result_type = type0; 3285 if (TREE_CODE (op1) == INTEGER_CST) 3286 { 3287 if (tree_int_cst_lt (op1, integer_zero_node)) 3288 warning (0, "%s rotate count is negative", 3289 (code == LROTATE_EXPR) ? "left" : "right"); 3290 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 3291 warning (0, "%s rotate count >= width of type", 3292 (code == LROTATE_EXPR) ? "left" : "right"); 3293 } 3294 /* Convert the shift-count to an integer, regardless of 3295 size of value being shifted. */ 3296 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 3297 op1 = cp_convert (integer_type_node, op1); 3298 } 3299 break; 3300 3301 case EQ_EXPR: 3302 case NE_EXPR: 3303 if (code0 == REAL_TYPE || code1 == REAL_TYPE) 3304 warning (OPT_Wfloat_equal, 3305 "comparing floating point with == or != is unsafe"); 3306 if ((TREE_CODE (orig_op0) == STRING_CST && !integer_zerop (op1)) 3307 || (TREE_CODE (orig_op1) == STRING_CST && !integer_zerop (op0))) 3308 warning (OPT_Waddress, 3309 "comparison with string literal results in unspecified behaviour"); 3310 3311 build_type = boolean_type_node; 3312 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE 3313 || code0 == COMPLEX_TYPE) 3314 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 3315 || code1 == COMPLEX_TYPE)) 3316 short_compare = 1; 3317 else if ((code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3318 || (TYPE_PTRMEM_P (type0) && TYPE_PTRMEM_P (type1))) 3319 result_type = composite_pointer_type (type0, type1, op0, op1, 3320 "comparison"); 3321 else if ((code0 == POINTER_TYPE || TYPE_PTRMEM_P (type0)) 3322 && null_ptr_cst_p (op1)) 3323 result_type = type0; 3324 else if ((code1 == POINTER_TYPE || TYPE_PTRMEM_P (type1)) 3325 && null_ptr_cst_p (op0)) 3326 result_type = type1; 3327 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE) 3328 { 3329 result_type = type0; 3330 error ("ISO C++ forbids comparison between pointer and integer"); 3331 } 3332 else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE) 3333 { 3334 result_type = type1; 3335 error ("ISO C++ forbids comparison between pointer and integer"); 3336 } 3337 else if (TYPE_PTRMEMFUNC_P (type0) && null_ptr_cst_p (op1)) 3338 { 3339 op0 = build_ptrmemfunc_access_expr (op0, pfn_identifier); 3340 op1 = cp_convert (TREE_TYPE (op0), integer_zero_node); 3341 result_type = TREE_TYPE (op0); 3342 } 3343 else if (TYPE_PTRMEMFUNC_P (type1) && null_ptr_cst_p (op0)) 3344 return cp_build_binary_op (code, op1, op0); 3345 else if (TYPE_PTRMEMFUNC_P (type0) && TYPE_PTRMEMFUNC_P (type1) 3346 && same_type_p (type0, type1)) 3347 { 3348 /* E will be the final comparison. */ 3349 tree e; 3350 /* E1 and E2 are for scratch. */ 3351 tree e1; 3352 tree e2; 3353 tree pfn0; 3354 tree pfn1; 3355 tree delta0; 3356 tree delta1; 3357 3358 if (TREE_SIDE_EFFECTS (op0)) 3359 op0 = save_expr (op0); 3360 if (TREE_SIDE_EFFECTS (op1)) 3361 op1 = save_expr (op1); 3362 3363 /* We generate: 3364 3365 (op0.pfn == op1.pfn 3366 && (!op0.pfn || op0.delta == op1.delta)) 3367 3368 The reason for the `!op0.pfn' bit is that a NULL 3369 pointer-to-member is any member with a zero PFN; the 3370 DELTA field is unspecified. */ 3371 pfn0 = pfn_from_ptrmemfunc (op0); 3372 pfn1 = pfn_from_ptrmemfunc (op1); 3373 delta0 = build_ptrmemfunc_access_expr (op0, 3374 delta_identifier); 3375 delta1 = build_ptrmemfunc_access_expr (op1, 3376 delta_identifier); 3377 e1 = cp_build_binary_op (EQ_EXPR, delta0, delta1); 3378 e2 = cp_build_binary_op (EQ_EXPR, 3379 pfn0, 3380 cp_convert (TREE_TYPE (pfn0), 3381 integer_zero_node)); 3382 e1 = cp_build_binary_op (TRUTH_ORIF_EXPR, e1, e2); 3383 e2 = build2 (EQ_EXPR, boolean_type_node, pfn0, pfn1); 3384 e = cp_build_binary_op (TRUTH_ANDIF_EXPR, e2, e1); 3385 if (code == EQ_EXPR) 3386 return e; 3387 return cp_build_binary_op (EQ_EXPR, e, integer_zero_node); 3388 } 3389 else 3390 { 3391 gcc_assert (!TYPE_PTRMEMFUNC_P (type0) 3392 || !same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type0), 3393 type1)); 3394 gcc_assert (!TYPE_PTRMEMFUNC_P (type1) 3395 || !same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type1), 3396 type0)); 3397 } 3398 3399 break; 3400 3401 case MAX_EXPR: 3402 case MIN_EXPR: 3403 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE) 3404 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE)) 3405 shorten = 1; 3406 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3407 result_type = composite_pointer_type (type0, type1, op0, op1, 3408 "comparison"); 3409 break; 3410 3411 case LE_EXPR: 3412 case GE_EXPR: 3413 case LT_EXPR: 3414 case GT_EXPR: 3415 if (TREE_CODE (orig_op0) == STRING_CST 3416 || TREE_CODE (orig_op1) == STRING_CST) 3417 warning (OPT_Waddress, 3418 "comparison with string literal results in unspecified behaviour"); 3419 3420 build_type = boolean_type_node; 3421 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE) 3422 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE)) 3423 short_compare = 1; 3424 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3425 result_type = composite_pointer_type (type0, type1, op0, op1, 3426 "comparison"); 3427 else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST 3428 && integer_zerop (op1)) 3429 result_type = type0; 3430 else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST 3431 && integer_zerop (op0)) 3432 result_type = type1; 3433 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE) 3434 { 3435 result_type = type0; 3436 pedwarn ("ISO C++ forbids comparison between pointer and integer"); 3437 } 3438 else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE) 3439 { 3440 result_type = type1; 3441 pedwarn ("ISO C++ forbids comparison between pointer and integer"); 3442 } 3443 break; 3444 3445 case UNORDERED_EXPR: 3446 case ORDERED_EXPR: 3447 case UNLT_EXPR: 3448 case UNLE_EXPR: 3449 case UNGT_EXPR: 3450 case UNGE_EXPR: 3451 case UNEQ_EXPR: 3452 build_type = integer_type_node; 3453 if (code0 != REAL_TYPE || code1 != REAL_TYPE) 3454 { 3455 error ("unordered comparison on non-floating point argument"); 3456 return error_mark_node; 3457 } 3458 common = 1; 3459 break; 3460 3461 default: 3462 break; 3463 } 3464 3465 if (((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE) 3466 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 3467 || code1 == COMPLEX_TYPE))) 3468 arithmetic_types_p = 1; 3469 else 3470 { 3471 arithmetic_types_p = 0; 3472 /* Vector arithmetic is only allowed when both sides are vectors. */ 3473 if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE) 3474 { 3475 if (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1)) 3476 || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0), 3477 TREE_TYPE (type1))) 3478 { 3479 binary_op_error (code); 3480 return error_mark_node; 3481 } 3482 arithmetic_types_p = 1; 3483 } 3484 } 3485 /* Determine the RESULT_TYPE, if it is not already known. */ 3486 if (!result_type 3487 && arithmetic_types_p 3488 && (shorten || common || short_compare)) 3489 result_type = common_type (type0, type1); 3490 3491 if (!result_type) 3492 { 3493 error ("invalid operands of types %qT and %qT to binary %qO", 3494 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1), code); 3495 return error_mark_node; 3496 } 3497 3498 /* If we're in a template, the only thing we need to know is the 3499 RESULT_TYPE. */ 3500 if (processing_template_decl) 3501 return build2 (resultcode, 3502 build_type ? build_type : result_type, 3503 op0, op1); 3504 3505 if (arithmetic_types_p) 3506 { 3507 int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE); 3508 3509 /* For certain operations (which identify themselves by shorten != 0) 3510 if both args were extended from the same smaller type, 3511 do the arithmetic in that type and then extend. 3512 3513 shorten !=0 and !=1 indicates a bitwise operation. 3514 For them, this optimization is safe only if 3515 both args are zero-extended or both are sign-extended. 3516 Otherwise, we might change the result. 3517 Eg, (short)-1 | (unsigned short)-1 is (int)-1 3518 but calculated in (unsigned short) it would be (unsigned short)-1. */ 3519 3520 if (shorten && none_complex) 3521 { 3522 int unsigned0, unsigned1; 3523 tree arg0 = get_narrower (op0, &unsigned0); 3524 tree arg1 = get_narrower (op1, &unsigned1); 3525 /* UNS is 1 if the operation to be done is an unsigned one. */ 3526 int uns = TYPE_UNSIGNED (result_type); 3527 tree type; 3528 3529 final_type = result_type; 3530 3531 /* Handle the case that OP0 does not *contain* a conversion 3532 but it *requires* conversion to FINAL_TYPE. */ 3533 3534 if (op0 == arg0 && TREE_TYPE (op0) != final_type) 3535 unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0)); 3536 if (op1 == arg1 && TREE_TYPE (op1) != final_type) 3537 unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1)); 3538 3539 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */ 3540 3541 /* For bitwise operations, signedness of nominal type 3542 does not matter. Consider only how operands were extended. */ 3543 if (shorten == -1) 3544 uns = unsigned0; 3545 3546 /* Note that in all three cases below we refrain from optimizing 3547 an unsigned operation on sign-extended args. 3548 That would not be valid. */ 3549 3550 /* Both args variable: if both extended in same way 3551 from same width, do it in that width. 3552 Do it unsigned if args were zero-extended. */ 3553 if ((TYPE_PRECISION (TREE_TYPE (arg0)) 3554 < TYPE_PRECISION (result_type)) 3555 && (TYPE_PRECISION (TREE_TYPE (arg1)) 3556 == TYPE_PRECISION (TREE_TYPE (arg0))) 3557 && unsigned0 == unsigned1 3558 && (unsigned0 || !uns)) 3559 result_type = c_common_signed_or_unsigned_type 3560 (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1))); 3561 else if (TREE_CODE (arg0) == INTEGER_CST 3562 && (unsigned1 || !uns) 3563 && (TYPE_PRECISION (TREE_TYPE (arg1)) 3564 < TYPE_PRECISION (result_type)) 3565 && (type = c_common_signed_or_unsigned_type 3566 (unsigned1, TREE_TYPE (arg1)), 3567 int_fits_type_p (arg0, type))) 3568 result_type = type; 3569 else if (TREE_CODE (arg1) == INTEGER_CST 3570 && (unsigned0 || !uns) 3571 && (TYPE_PRECISION (TREE_TYPE (arg0)) 3572 < TYPE_PRECISION (result_type)) 3573 && (type = c_common_signed_or_unsigned_type 3574 (unsigned0, TREE_TYPE (arg0)), 3575 int_fits_type_p (arg1, type))) 3576 result_type = type; 3577 } 3578 3579 /* Shifts can be shortened if shifting right. */ 3580 3581 if (short_shift) 3582 { 3583 int unsigned_arg; 3584 tree arg0 = get_narrower (op0, &unsigned_arg); 3585 3586 final_type = result_type; 3587 3588 if (arg0 == op0 && final_type == TREE_TYPE (op0)) 3589 unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0)); 3590 3591 if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type) 3592 /* We can shorten only if the shift count is less than the 3593 number of bits in the smaller type size. */ 3594 && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0 3595 /* If arg is sign-extended and then unsigned-shifted, 3596 we can simulate this with a signed shift in arg's type 3597 only if the extended result is at least twice as wide 3598 as the arg. Otherwise, the shift could use up all the 3599 ones made by sign-extension and bring in zeros. 3600 We can't optimize that case at all, but in most machines 3601 it never happens because available widths are 2**N. */ 3602 && (!TYPE_UNSIGNED (final_type) 3603 || unsigned_arg 3604 || (((unsigned) 2 * TYPE_PRECISION (TREE_TYPE (arg0))) 3605 <= TYPE_PRECISION (result_type)))) 3606 { 3607 /* Do an unsigned shift if the operand was zero-extended. */ 3608 result_type 3609 = c_common_signed_or_unsigned_type (unsigned_arg, 3610 TREE_TYPE (arg0)); 3611 /* Convert value-to-be-shifted to that type. */ 3612 if (TREE_TYPE (op0) != result_type) 3613 op0 = cp_convert (result_type, op0); 3614 converted = 1; 3615 } 3616 } 3617 3618 /* Comparison operations are shortened too but differently. 3619 They identify themselves by setting short_compare = 1. */ 3620 3621 if (short_compare) 3622 { 3623 /* Don't write &op0, etc., because that would prevent op0 3624 from being kept in a register. 3625 Instead, make copies of the our local variables and 3626 pass the copies by reference, then copy them back afterward. */ 3627 tree xop0 = op0, xop1 = op1, xresult_type = result_type; 3628 enum tree_code xresultcode = resultcode; 3629 tree val 3630 = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode); 3631 if (val != 0) 3632 return cp_convert (boolean_type_node, val); 3633 op0 = xop0, op1 = xop1; 3634 converted = 1; 3635 resultcode = xresultcode; 3636 } 3637 3638 if ((short_compare || code == MIN_EXPR || code == MAX_EXPR) 3639 && warn_sign_compare 3640 /* Do not warn until the template is instantiated; we cannot 3641 bound the ranges of the arguments until that point. */ 3642 && !processing_template_decl) 3643 { 3644 int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0)); 3645 int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1)); 3646 3647 int unsignedp0, unsignedp1; 3648 tree primop0 = get_narrower (op0, &unsignedp0); 3649 tree primop1 = get_narrower (op1, &unsignedp1); 3650 3651 /* Check for comparison of different enum types. */ 3652 if (TREE_CODE (TREE_TYPE (orig_op0)) == ENUMERAL_TYPE 3653 && TREE_CODE (TREE_TYPE (orig_op1)) == ENUMERAL_TYPE 3654 && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0)) 3655 != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1))) 3656 { 3657 warning (0, "comparison between types %q#T and %q#T", 3658 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1)); 3659 } 3660 3661 /* Give warnings for comparisons between signed and unsigned 3662 quantities that may fail. */ 3663 /* Do the checking based on the original operand trees, so that 3664 casts will be considered, but default promotions won't be. */ 3665 3666 /* Do not warn if the comparison is being done in a signed type, 3667 since the signed type will only be chosen if it can represent 3668 all the values of the unsigned type. */ 3669 if (!TYPE_UNSIGNED (result_type)) 3670 /* OK */; 3671 /* Do not warn if both operands are unsigned. */ 3672 else if (op0_signed == op1_signed) 3673 /* OK */; 3674 /* Do not warn if the signed quantity is an unsuffixed 3675 integer literal (or some static constant expression 3676 involving such literals or a conditional expression 3677 involving such literals) and it is non-negative. */ 3678 else if ((op0_signed && tree_expr_nonnegative_p (orig_op0)) 3679 || (op1_signed && tree_expr_nonnegative_p (orig_op1))) 3680 /* OK */; 3681 /* Do not warn if the comparison is an equality operation, 3682 the unsigned quantity is an integral constant and it does 3683 not use the most significant bit of result_type. */ 3684 else if ((resultcode == EQ_EXPR || resultcode == NE_EXPR) 3685 && ((op0_signed && TREE_CODE (orig_op1) == INTEGER_CST 3686 && int_fits_type_p (orig_op1, c_common_signed_type 3687 (result_type))) 3688 || (op1_signed && TREE_CODE (orig_op0) == INTEGER_CST 3689 && int_fits_type_p (orig_op0, c_common_signed_type 3690 (result_type))))) 3691 /* OK */; 3692 else 3693 warning (0, "comparison between signed and unsigned integer expressions"); 3694 3695 /* Warn if two unsigned values are being compared in a size 3696 larger than their original size, and one (and only one) is the 3697 result of a `~' operator. This comparison will always fail. 3698 3699 Also warn if one operand is a constant, and the constant does not 3700 have all bits set that are set in the ~ operand when it is 3701 extended. */ 3702 3703 if ((TREE_CODE (primop0) == BIT_NOT_EXPR) 3704 ^ (TREE_CODE (primop1) == BIT_NOT_EXPR)) 3705 { 3706 if (TREE_CODE (primop0) == BIT_NOT_EXPR) 3707 primop0 = get_narrower (TREE_OPERAND (op0, 0), &unsignedp0); 3708 if (TREE_CODE (primop1) == BIT_NOT_EXPR) 3709 primop1 = get_narrower (TREE_OPERAND (op1, 0), &unsignedp1); 3710 3711 if (host_integerp (primop0, 0) || host_integerp (primop1, 0)) 3712 { 3713 tree primop; 3714 HOST_WIDE_INT constant, mask; 3715 int unsignedp; 3716 unsigned int bits; 3717 3718 if (host_integerp (primop0, 0)) 3719 { 3720 primop = primop1; 3721 unsignedp = unsignedp1; 3722 constant = tree_low_cst (primop0, 0); 3723 } 3724 else 3725 { 3726 primop = primop0; 3727 unsignedp = unsignedp0; 3728 constant = tree_low_cst (primop1, 0); 3729 } 3730 3731 bits = TYPE_PRECISION (TREE_TYPE (primop)); 3732 if (bits < TYPE_PRECISION (result_type) 3733 && bits < HOST_BITS_PER_LONG && unsignedp) 3734 { 3735 mask = (~ (HOST_WIDE_INT) 0) << bits; 3736 if ((mask & constant) != mask) 3737 warning (0, "comparison of promoted ~unsigned with constant"); 3738 } 3739 } 3740 else if (unsignedp0 && unsignedp1 3741 && (TYPE_PRECISION (TREE_TYPE (primop0)) 3742 < TYPE_PRECISION (result_type)) 3743 && (TYPE_PRECISION (TREE_TYPE (primop1)) 3744 < TYPE_PRECISION (result_type))) 3745 warning (0, "comparison of promoted ~unsigned with unsigned"); 3746 } 3747 } 3748 } 3749 3750 /* If CONVERTED is zero, both args will be converted to type RESULT_TYPE. 3751 Then the expression will be built. 3752 It will be given type FINAL_TYPE if that is nonzero; 3753 otherwise, it will be given type RESULT_TYPE. */ 3754 3755 /* Issue warnings about peculiar, but valid, uses of NULL. */ 3756 if (/* It's reasonable to use pointer values as operands of && 3757 and ||, so NULL is no exception. */ 3758 !(code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR) 3759 && (/* If OP0 is NULL and OP1 is not a pointer, or vice versa. */ 3760 (orig_op0 == null_node 3761 && TREE_CODE (TREE_TYPE (op1)) != POINTER_TYPE) 3762 /* Or vice versa. */ 3763 || (orig_op1 == null_node 3764 && TREE_CODE (TREE_TYPE (op0)) != POINTER_TYPE) 3765 /* Or, both are NULL and the operation was not a comparison. */ 3766 || (orig_op0 == null_node && orig_op1 == null_node 3767 && code != EQ_EXPR && code != NE_EXPR))) 3768 /* Some sort of arithmetic operation involving NULL was 3769 performed. Note that pointer-difference and pointer-addition 3770 have already been handled above, and so we don't end up here in 3771 that case. */ 3772 warning (0, "NULL used in arithmetic"); 3773 3774 if (! converted) 3775 { 3776 if (TREE_TYPE (op0) != result_type) 3777 op0 = cp_convert (result_type, op0); 3778 if (TREE_TYPE (op1) != result_type) 3779 op1 = cp_convert (result_type, op1); 3780 3781 if (op0 == error_mark_node || op1 == error_mark_node) 3782 return error_mark_node; 3783 } 3784 3785 if (build_type == NULL_TREE) 3786 build_type = result_type; 3787 3788 result = build2 (resultcode, build_type, op0, op1); 3789 result = fold_if_not_in_template (result); 3790 if (final_type != 0) 3791 result = cp_convert (final_type, result); 3792 3793 if (TREE_OVERFLOW_P (result) 3794 && !TREE_OVERFLOW_P (op0) 3795 && !TREE_OVERFLOW_P (op1)) 3796 overflow_warning (result); 3797 3798 return result; 3799} 3800 3801/* Return a tree for the sum or difference (RESULTCODE says which) 3802 of pointer PTROP and integer INTOP. */ 3803 3804static tree 3805cp_pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop) 3806{ 3807 tree res_type = TREE_TYPE (ptrop); 3808 3809 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type) 3810 in certain circumstance (when it's valid to do so). So we need 3811 to make sure it's complete. We don't need to check here, if we 3812 can actually complete it at all, as those checks will be done in 3813 pointer_int_sum() anyway. */ 3814 complete_type (TREE_TYPE (res_type)); 3815 3816 return pointer_int_sum (resultcode, ptrop, 3817 fold_if_not_in_template (intop)); 3818} 3819 3820/* Return a tree for the difference of pointers OP0 and OP1. 3821 The resulting tree has type int. */ 3822 3823static tree 3824pointer_diff (tree op0, tree op1, tree ptrtype) 3825{ 3826 tree result; 3827 tree restype = ptrdiff_type_node; 3828 tree target_type = TREE_TYPE (ptrtype); 3829 3830 if (!complete_type_or_else (target_type, NULL_TREE)) 3831 return error_mark_node; 3832 3833 if (pedantic || warn_pointer_arith) 3834 { 3835 if (TREE_CODE (target_type) == VOID_TYPE) 3836 pedwarn ("ISO C++ forbids using pointer of type %<void *%> in subtraction"); 3837 if (TREE_CODE (target_type) == FUNCTION_TYPE) 3838 pedwarn ("ISO C++ forbids using pointer to a function in subtraction"); 3839 if (TREE_CODE (target_type) == METHOD_TYPE) 3840 pedwarn ("ISO C++ forbids using pointer to a method in subtraction"); 3841 } 3842 3843 /* First do the subtraction as integers; 3844 then drop through to build the divide operator. */ 3845 3846 op0 = cp_build_binary_op (MINUS_EXPR, 3847 cp_convert (restype, op0), 3848 cp_convert (restype, op1)); 3849 3850 /* This generates an error if op1 is a pointer to an incomplete type. */ 3851 if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (op1)))) 3852 error ("invalid use of a pointer to an incomplete type in pointer arithmetic"); 3853 3854 op1 = (TYPE_PTROB_P (ptrtype) 3855 ? size_in_bytes (target_type) 3856 : integer_one_node); 3857 3858 /* Do the division. */ 3859 3860 result = build2 (EXACT_DIV_EXPR, restype, op0, cp_convert (restype, op1)); 3861 return fold_if_not_in_template (result); 3862} 3863 3864/* Construct and perhaps optimize a tree representation 3865 for a unary operation. CODE, a tree_code, specifies the operation 3866 and XARG is the operand. */ 3867 3868tree 3869build_x_unary_op (enum tree_code code, tree xarg) 3870{ 3871 tree orig_expr = xarg; 3872 tree exp; 3873 int ptrmem = 0; 3874 3875 if (processing_template_decl) 3876 { 3877 if (type_dependent_expression_p (xarg)) 3878 return build_min_nt (code, xarg, NULL_TREE); 3879 3880 xarg = build_non_dependent_expr (xarg); 3881 } 3882 3883 exp = NULL_TREE; 3884 3885 /* [expr.unary.op] says: 3886 3887 The address of an object of incomplete type can be taken. 3888 3889 (And is just the ordinary address operator, not an overloaded 3890 "operator &".) However, if the type is a template 3891 specialization, we must complete the type at this point so that 3892 an overloaded "operator &" will be available if required. */ 3893 if (code == ADDR_EXPR 3894 && TREE_CODE (xarg) != TEMPLATE_ID_EXPR 3895 && ((CLASS_TYPE_P (TREE_TYPE (xarg)) 3896 && !COMPLETE_TYPE_P (complete_type (TREE_TYPE (xarg)))) 3897 || (TREE_CODE (xarg) == OFFSET_REF))) 3898 /* Don't look for a function. */; 3899 else 3900 exp = build_new_op (code, LOOKUP_NORMAL, xarg, NULL_TREE, NULL_TREE, 3901 /*overloaded_p=*/NULL); 3902 if (!exp && code == ADDR_EXPR) 3903 { 3904 /* A pointer to member-function can be formed only by saying 3905 &X::mf. */ 3906 if (!flag_ms_extensions && TREE_CODE (TREE_TYPE (xarg)) == METHOD_TYPE 3907 && (TREE_CODE (xarg) != OFFSET_REF || !PTRMEM_OK_P (xarg))) 3908 { 3909 if (TREE_CODE (xarg) != OFFSET_REF 3910 || !TYPE_P (TREE_OPERAND (xarg, 0))) 3911 { 3912 error ("invalid use of %qE to form a pointer-to-member-function", 3913 xarg); 3914 if (TREE_CODE (xarg) != OFFSET_REF) 3915 inform (" a qualified-id is required"); 3916 return error_mark_node; 3917 } 3918 else 3919 { 3920 error ("parentheses around %qE cannot be used to form a" 3921 " pointer-to-member-function", 3922 xarg); 3923 PTRMEM_OK_P (xarg) = 1; 3924 } 3925 } 3926 3927 if (TREE_CODE (xarg) == OFFSET_REF) 3928 { 3929 ptrmem = PTRMEM_OK_P (xarg); 3930 3931 if (!ptrmem && !flag_ms_extensions 3932 && TREE_CODE (TREE_TYPE (TREE_OPERAND (xarg, 1))) == METHOD_TYPE) 3933 { 3934 /* A single non-static member, make sure we don't allow a 3935 pointer-to-member. */ 3936 xarg = build2 (OFFSET_REF, TREE_TYPE (xarg), 3937 TREE_OPERAND (xarg, 0), 3938 ovl_cons (TREE_OPERAND (xarg, 1), NULL_TREE)); 3939 PTRMEM_OK_P (xarg) = ptrmem; 3940 } 3941 } 3942 else if (TREE_CODE (xarg) == TARGET_EXPR) 3943 warning (0, "taking address of temporary"); 3944 exp = build_unary_op (ADDR_EXPR, xarg, 0); 3945 } 3946 3947 if (processing_template_decl && exp != error_mark_node) 3948 exp = build_min_non_dep (code, exp, orig_expr, 3949 /*For {PRE,POST}{INC,DEC}REMENT_EXPR*/NULL_TREE); 3950 if (TREE_CODE (exp) == ADDR_EXPR) 3951 PTRMEM_OK_P (exp) = ptrmem; 3952 return exp; 3953} 3954 3955/* Like c_common_truthvalue_conversion, but handle pointer-to-member 3956 constants, where a null value is represented by an INTEGER_CST of 3957 -1. */ 3958 3959tree 3960cp_truthvalue_conversion (tree expr) 3961{ 3962 tree type = TREE_TYPE (expr); 3963 if (TYPE_PTRMEM_P (type)) 3964 return build_binary_op (NE_EXPR, expr, integer_zero_node, 1); 3965 else 3966 return c_common_truthvalue_conversion (expr); 3967} 3968 3969/* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */ 3970 3971tree 3972condition_conversion (tree expr) 3973{ 3974 tree t; 3975 if (processing_template_decl) 3976 return expr; 3977 t = perform_implicit_conversion (boolean_type_node, expr); 3978 t = fold_build_cleanup_point_expr (boolean_type_node, t); 3979 return t; 3980} 3981 3982/* Return an ADDR_EXPR giving the address of T. This function 3983 attempts no optimizations or simplifications; it is a low-level 3984 primitive. */ 3985 3986tree 3987build_address (tree t) 3988{ 3989 tree addr; 3990 3991 if (error_operand_p (t) || !cxx_mark_addressable (t)) 3992 return error_mark_node; 3993 3994 addr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (t)), t); 3995 3996 return addr; 3997} 3998 3999/* Return a NOP_EXPR converting EXPR to TYPE. */ 4000 4001tree 4002build_nop (tree type, tree expr) 4003{ 4004 if (type == error_mark_node || error_operand_p (expr)) 4005 return expr; 4006 return build1 (NOP_EXPR, type, expr); 4007} 4008 4009/* C++: Must handle pointers to members. 4010 4011 Perhaps type instantiation should be extended to handle conversion 4012 from aggregates to types we don't yet know we want? (Or are those 4013 cases typically errors which should be reported?) 4014 4015 NOCONVERT nonzero suppresses the default promotions 4016 (such as from short to int). */ 4017 4018tree 4019build_unary_op (enum tree_code code, tree xarg, int noconvert) 4020{ 4021 /* No default_conversion here. It causes trouble for ADDR_EXPR. */ 4022 tree arg = xarg; 4023 tree argtype = 0; 4024 const char *errstring = NULL; 4025 tree val; 4026 const char *invalid_op_diag; 4027 4028 if (arg == error_mark_node) 4029 return error_mark_node; 4030 4031 if ((invalid_op_diag 4032 = targetm.invalid_unary_op ((code == UNARY_PLUS_EXPR 4033 ? CONVERT_EXPR 4034 : code), 4035 TREE_TYPE (xarg)))) 4036 { 4037 error (invalid_op_diag); 4038 return error_mark_node; 4039 } 4040 4041 switch (code) 4042 { 4043 case UNARY_PLUS_EXPR: 4044 case NEGATE_EXPR: 4045 { 4046 int flags = WANT_ARITH | WANT_ENUM; 4047 /* Unary plus (but not unary minus) is allowed on pointers. */ 4048 if (code == UNARY_PLUS_EXPR) 4049 flags |= WANT_POINTER; 4050 arg = build_expr_type_conversion (flags, arg, true); 4051 if (!arg) 4052 errstring = (code == NEGATE_EXPR 4053 ? "wrong type argument to unary minus" 4054 : "wrong type argument to unary plus"); 4055 else 4056 { 4057 if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg))) 4058 arg = perform_integral_promotions (arg); 4059 4060 /* Make sure the result is not an lvalue: a unary plus or minus 4061 expression is always a rvalue. */ 4062 arg = rvalue (arg); 4063 } 4064 } 4065 break; 4066 4067 case BIT_NOT_EXPR: 4068 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4069 { 4070 code = CONJ_EXPR; 4071 if (!noconvert) 4072 arg = default_conversion (arg); 4073 } 4074 else if (!(arg = build_expr_type_conversion (WANT_INT | WANT_ENUM 4075 | WANT_VECTOR, 4076 arg, true))) 4077 errstring = "wrong type argument to bit-complement"; 4078 else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg))) 4079 arg = perform_integral_promotions (arg); 4080 break; 4081 4082 case ABS_EXPR: 4083 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true))) 4084 errstring = "wrong type argument to abs"; 4085 else if (!noconvert) 4086 arg = default_conversion (arg); 4087 break; 4088 4089 case CONJ_EXPR: 4090 /* Conjugating a real value is a no-op, but allow it anyway. */ 4091 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true))) 4092 errstring = "wrong type argument to conjugation"; 4093 else if (!noconvert) 4094 arg = default_conversion (arg); 4095 break; 4096 4097 case TRUTH_NOT_EXPR: 4098 arg = perform_implicit_conversion (boolean_type_node, arg); 4099 val = invert_truthvalue (arg); 4100 if (arg != error_mark_node) 4101 return val; 4102 errstring = "in argument to unary !"; 4103 break; 4104 4105 case NOP_EXPR: 4106 break; 4107 4108 case REALPART_EXPR: 4109 if (TREE_CODE (arg) == COMPLEX_CST) 4110 return TREE_REALPART (arg); 4111 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4112 { 4113 arg = build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg); 4114 return fold_if_not_in_template (arg); 4115 } 4116 else 4117 return arg; 4118 4119 case IMAGPART_EXPR: 4120 if (TREE_CODE (arg) == COMPLEX_CST) 4121 return TREE_IMAGPART (arg); 4122 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4123 { 4124 arg = build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg); 4125 return fold_if_not_in_template (arg); 4126 } 4127 else 4128 return cp_convert (TREE_TYPE (arg), integer_zero_node); 4129 4130 case PREINCREMENT_EXPR: 4131 case POSTINCREMENT_EXPR: 4132 case PREDECREMENT_EXPR: 4133 case POSTDECREMENT_EXPR: 4134 /* Handle complex lvalues (when permitted) 4135 by reduction to simpler cases. */ 4136 4137 val = unary_complex_lvalue (code, arg); 4138 if (val != 0) 4139 return val; 4140 4141 /* Increment or decrement the real part of the value, 4142 and don't change the imaginary part. */ 4143 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4144 { 4145 tree real, imag; 4146 4147 arg = stabilize_reference (arg); 4148 real = build_unary_op (REALPART_EXPR, arg, 1); 4149 imag = build_unary_op (IMAGPART_EXPR, arg, 1); 4150 return build2 (COMPLEX_EXPR, TREE_TYPE (arg), 4151 build_unary_op (code, real, 1), imag); 4152 } 4153 4154 /* Report invalid types. */ 4155 4156 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_POINTER, 4157 arg, true))) 4158 { 4159 if (code == PREINCREMENT_EXPR) 4160 errstring ="no pre-increment operator for type"; 4161 else if (code == POSTINCREMENT_EXPR) 4162 errstring ="no post-increment operator for type"; 4163 else if (code == PREDECREMENT_EXPR) 4164 errstring ="no pre-decrement operator for type"; 4165 else 4166 errstring ="no post-decrement operator for type"; 4167 break; 4168 } 4169 4170 /* Report something read-only. */ 4171 4172 if (CP_TYPE_CONST_P (TREE_TYPE (arg)) 4173 || TREE_READONLY (arg)) 4174 readonly_error (arg, ((code == PREINCREMENT_EXPR 4175 || code == POSTINCREMENT_EXPR) 4176 ? "increment" : "decrement"), 4177 0); 4178 4179 { 4180 tree inc; 4181 tree declared_type; 4182 tree result_type = TREE_TYPE (arg); 4183 4184 declared_type = unlowered_expr_type (arg); 4185 4186 arg = get_unwidened (arg, 0); 4187 argtype = TREE_TYPE (arg); 4188 4189 /* ARM $5.2.5 last annotation says this should be forbidden. */ 4190 if (TREE_CODE (argtype) == ENUMERAL_TYPE) 4191 pedwarn ("ISO C++ forbids %sing an enum", 4192 (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR) 4193 ? "increment" : "decrement"); 4194 4195 /* Compute the increment. */ 4196 4197 if (TREE_CODE (argtype) == POINTER_TYPE) 4198 { 4199 tree type = complete_type (TREE_TYPE (argtype)); 4200 4201 if (!COMPLETE_OR_VOID_TYPE_P (type)) 4202 error ("cannot %s a pointer to incomplete type %qT", 4203 ((code == PREINCREMENT_EXPR 4204 || code == POSTINCREMENT_EXPR) 4205 ? "increment" : "decrement"), TREE_TYPE (argtype)); 4206 else if ((pedantic || warn_pointer_arith) 4207 && !TYPE_PTROB_P (argtype)) 4208 pedwarn ("ISO C++ forbids %sing a pointer of type %qT", 4209 ((code == PREINCREMENT_EXPR 4210 || code == POSTINCREMENT_EXPR) 4211 ? "increment" : "decrement"), argtype); 4212 inc = cxx_sizeof_nowarn (TREE_TYPE (argtype)); 4213 } 4214 else 4215 inc = integer_one_node; 4216 4217 inc = cp_convert (argtype, inc); 4218 4219 /* Handle incrementing a cast-expression. */ 4220 4221 switch (TREE_CODE (arg)) 4222 { 4223 case NOP_EXPR: 4224 case CONVERT_EXPR: 4225 case FLOAT_EXPR: 4226 case FIX_TRUNC_EXPR: 4227 case FIX_FLOOR_EXPR: 4228 case FIX_ROUND_EXPR: 4229 case FIX_CEIL_EXPR: 4230 { 4231 tree incremented, modify, value, compound; 4232 if (! lvalue_p (arg) && pedantic) 4233 pedwarn ("cast to non-reference type used as lvalue"); 4234 arg = stabilize_reference (arg); 4235 if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) 4236 value = arg; 4237 else 4238 value = save_expr (arg); 4239 incremented = build2 (((code == PREINCREMENT_EXPR 4240 || code == POSTINCREMENT_EXPR) 4241 ? PLUS_EXPR : MINUS_EXPR), 4242 argtype, value, inc); 4243 4244 modify = build_modify_expr (arg, NOP_EXPR, incremented); 4245 compound = build2 (COMPOUND_EXPR, TREE_TYPE (arg), 4246 modify, value); 4247 4248 /* Eliminate warning about unused result of + or -. */ 4249 TREE_NO_WARNING (compound) = 1; 4250 return compound; 4251 } 4252 4253 default: 4254 break; 4255 } 4256 4257 /* Complain about anything else that is not a true lvalue. */ 4258 if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR 4259 || code == POSTINCREMENT_EXPR) 4260 ? lv_increment : lv_decrement))) 4261 return error_mark_node; 4262 4263 /* Forbid using -- on `bool'. */ 4264 if (same_type_p (declared_type, boolean_type_node)) 4265 { 4266 if (code == POSTDECREMENT_EXPR || code == PREDECREMENT_EXPR) 4267 { 4268 error ("invalid use of %<--%> on bool variable %qD", arg); 4269 return error_mark_node; 4270 } 4271 val = boolean_increment (code, arg); 4272 } 4273 else 4274 val = build2 (code, TREE_TYPE (arg), arg, inc); 4275 4276 TREE_SIDE_EFFECTS (val) = 1; 4277 return cp_convert (result_type, val); 4278 } 4279 4280 case ADDR_EXPR: 4281 /* Note that this operation never does default_conversion 4282 regardless of NOCONVERT. */ 4283 4284 argtype = lvalue_type (arg); 4285 4286 if (TREE_CODE (arg) == OFFSET_REF) 4287 goto offset_ref; 4288 4289 if (TREE_CODE (argtype) == REFERENCE_TYPE) 4290 { 4291 tree type = build_pointer_type (TREE_TYPE (argtype)); 4292 arg = build1 (CONVERT_EXPR, type, arg); 4293 return arg; 4294 } 4295 else if (pedantic && DECL_MAIN_P (arg)) 4296 /* ARM $3.4 */ 4297 pedwarn ("ISO C++ forbids taking address of function %<::main%>"); 4298 4299 /* Let &* cancel out to simplify resulting code. */ 4300 if (TREE_CODE (arg) == INDIRECT_REF) 4301 { 4302 /* We don't need to have `current_class_ptr' wrapped in a 4303 NON_LVALUE_EXPR node. */ 4304 if (arg == current_class_ref) 4305 return current_class_ptr; 4306 4307 arg = TREE_OPERAND (arg, 0); 4308 if (TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE) 4309 { 4310 tree type = build_pointer_type (TREE_TYPE (TREE_TYPE (arg))); 4311 arg = build1 (CONVERT_EXPR, type, arg); 4312 } 4313 else 4314 /* Don't let this be an lvalue. */ 4315 arg = rvalue (arg); 4316 return arg; 4317 } 4318 4319 /* Uninstantiated types are all functions. Taking the 4320 address of a function is a no-op, so just return the 4321 argument. */ 4322 4323 gcc_assert (TREE_CODE (arg) != IDENTIFIER_NODE 4324 || !IDENTIFIER_OPNAME_P (arg)); 4325 4326 if (TREE_CODE (arg) == COMPONENT_REF && type_unknown_p (arg) 4327 && !really_overloaded_fn (TREE_OPERAND (arg, 1))) 4328 { 4329 /* They're trying to take the address of a unique non-static 4330 member function. This is ill-formed (except in MS-land), 4331 but let's try to DTRT. 4332 Note: We only handle unique functions here because we don't 4333 want to complain if there's a static overload; non-unique 4334 cases will be handled by instantiate_type. But we need to 4335 handle this case here to allow casts on the resulting PMF. 4336 We could defer this in non-MS mode, but it's easier to give 4337 a useful error here. */ 4338 4339 /* Inside constant member functions, the `this' pointer 4340 contains an extra const qualifier. TYPE_MAIN_VARIANT 4341 is used here to remove this const from the diagnostics 4342 and the created OFFSET_REF. */ 4343 tree base = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (arg, 0))); 4344 tree fn = get_first_fn (TREE_OPERAND (arg, 1)); 4345 mark_used (fn); 4346 4347 if (! flag_ms_extensions) 4348 { 4349 tree name = DECL_NAME (fn); 4350 if (current_class_type 4351 && TREE_OPERAND (arg, 0) == current_class_ref) 4352 /* An expression like &memfn. */ 4353 pedwarn ("ISO C++ forbids taking the address of an unqualified" 4354 " or parenthesized non-static member function to form" 4355 " a pointer to member function. Say %<&%T::%D%>", 4356 base, name); 4357 else 4358 pedwarn ("ISO C++ forbids taking the address of a bound member" 4359 " function to form a pointer to member function." 4360 " Say %<&%T::%D%>", 4361 base, name); 4362 } 4363 arg = build_offset_ref (base, fn, /*address_p=*/true); 4364 } 4365 4366 offset_ref: 4367 if (type_unknown_p (arg)) 4368 return build1 (ADDR_EXPR, unknown_type_node, arg); 4369 4370 /* Handle complex lvalues (when permitted) 4371 by reduction to simpler cases. */ 4372 val = unary_complex_lvalue (code, arg); 4373 if (val != 0) 4374 return val; 4375 4376 switch (TREE_CODE (arg)) 4377 { 4378 case NOP_EXPR: 4379 case CONVERT_EXPR: 4380 case FLOAT_EXPR: 4381 case FIX_TRUNC_EXPR: 4382 case FIX_FLOOR_EXPR: 4383 case FIX_ROUND_EXPR: 4384 case FIX_CEIL_EXPR: 4385 if (! lvalue_p (arg) && pedantic) 4386 pedwarn ("ISO C++ forbids taking the address of a cast to a non-lvalue expression"); 4387 break; 4388 4389 case BASELINK: 4390 arg = BASELINK_FUNCTIONS (arg); 4391 /* Fall through. */ 4392 4393 case OVERLOAD: 4394 arg = OVL_CURRENT (arg); 4395 break; 4396 4397 case OFFSET_REF: 4398 /* Turn a reference to a non-static data member into a 4399 pointer-to-member. */ 4400 { 4401 tree type; 4402 tree t; 4403 4404 if (!PTRMEM_OK_P (arg)) 4405 return build_unary_op (code, arg, 0); 4406 4407 t = TREE_OPERAND (arg, 1); 4408 if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) 4409 { 4410 error ("cannot create pointer to reference member %qD", t); 4411 return error_mark_node; 4412 } 4413 4414 type = build_ptrmem_type (context_for_name_lookup (t), 4415 TREE_TYPE (t)); 4416 t = make_ptrmem_cst (type, TREE_OPERAND (arg, 1)); 4417 return t; 4418 } 4419 4420 default: 4421 break; 4422 } 4423 4424 /* Anything not already handled and not a true memory reference 4425 is an error. */ 4426 if (TREE_CODE (argtype) != FUNCTION_TYPE 4427 && TREE_CODE (argtype) != METHOD_TYPE 4428 && TREE_CODE (arg) != OFFSET_REF 4429 && !lvalue_or_else (arg, lv_addressof)) 4430 return error_mark_node; 4431 4432 if (argtype != error_mark_node) 4433 argtype = build_pointer_type (argtype); 4434 4435 /* In a template, we are processing a non-dependent expression 4436 so we can just form an ADDR_EXPR with the correct type. */ 4437 if (processing_template_decl) 4438 { 4439 val = build_address (arg); 4440 if (TREE_CODE (arg) == OFFSET_REF) 4441 PTRMEM_OK_P (val) = PTRMEM_OK_P (arg); 4442 return val; 4443 } 4444 4445 if (TREE_CODE (arg) != COMPONENT_REF) 4446 { 4447 val = build_address (arg); 4448 if (TREE_CODE (arg) == OFFSET_REF) 4449 PTRMEM_OK_P (val) = PTRMEM_OK_P (arg); 4450 } 4451 else if (TREE_CODE (TREE_OPERAND (arg, 1)) == BASELINK) 4452 { 4453 tree fn = BASELINK_FUNCTIONS (TREE_OPERAND (arg, 1)); 4454 4455 /* We can only get here with a single static member 4456 function. */ 4457 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL 4458 && DECL_STATIC_FUNCTION_P (fn)); 4459 mark_used (fn); 4460 val = build_address (fn); 4461 if (TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0))) 4462 /* Do not lose object's side effects. */ 4463 val = build2 (COMPOUND_EXPR, TREE_TYPE (val), 4464 TREE_OPERAND (arg, 0), val); 4465 } 4466 else if (DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1))) 4467 { 4468 error ("attempt to take address of bit-field structure member %qD", 4469 TREE_OPERAND (arg, 1)); 4470 return error_mark_node; 4471 } 4472 else 4473 { 4474 tree object = TREE_OPERAND (arg, 0); 4475 tree field = TREE_OPERAND (arg, 1); 4476 gcc_assert (same_type_ignoring_top_level_qualifiers_p 4477 (TREE_TYPE (object), decl_type_context (field))); 4478 val = build_address (arg); 4479 } 4480 4481 if (TREE_CODE (argtype) == POINTER_TYPE 4482 && TREE_CODE (TREE_TYPE (argtype)) == METHOD_TYPE) 4483 { 4484 build_ptrmemfunc_type (argtype); 4485 val = build_ptrmemfunc (argtype, val, 0, 4486 /*c_cast_p=*/false); 4487 } 4488 4489 return val; 4490 4491 default: 4492 break; 4493 } 4494 4495 if (!errstring) 4496 { 4497 if (argtype == 0) 4498 argtype = TREE_TYPE (arg); 4499 return fold_if_not_in_template (build1 (code, argtype, arg)); 4500 } 4501 4502 error ("%s", errstring); 4503 return error_mark_node; 4504} 4505 4506/* Apply unary lvalue-demanding operator CODE to the expression ARG 4507 for certain kinds of expressions which are not really lvalues 4508 but which we can accept as lvalues. 4509 4510 If ARG is not a kind of expression we can handle, return 4511 NULL_TREE. */ 4512 4513tree 4514unary_complex_lvalue (enum tree_code code, tree arg) 4515{ 4516 /* Inside a template, making these kinds of adjustments is 4517 pointless; we are only concerned with the type of the 4518 expression. */ 4519 if (processing_template_decl) 4520 return NULL_TREE; 4521 4522 /* Handle (a, b) used as an "lvalue". */ 4523 if (TREE_CODE (arg) == COMPOUND_EXPR) 4524 { 4525 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 1), 0); 4526 return build2 (COMPOUND_EXPR, TREE_TYPE (real_result), 4527 TREE_OPERAND (arg, 0), real_result); 4528 } 4529 4530 /* Handle (a ? b : c) used as an "lvalue". */ 4531 if (TREE_CODE (arg) == COND_EXPR 4532 || TREE_CODE (arg) == MIN_EXPR || TREE_CODE (arg) == MAX_EXPR) 4533 return rationalize_conditional_expr (code, arg); 4534 4535 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */ 4536 if (TREE_CODE (arg) == MODIFY_EXPR 4537 || TREE_CODE (arg) == PREINCREMENT_EXPR 4538 || TREE_CODE (arg) == PREDECREMENT_EXPR) 4539 { 4540 tree lvalue = TREE_OPERAND (arg, 0); 4541 if (TREE_SIDE_EFFECTS (lvalue)) 4542 { 4543 lvalue = stabilize_reference (lvalue); 4544 arg = build2 (TREE_CODE (arg), TREE_TYPE (arg), 4545 lvalue, TREE_OPERAND (arg, 1)); 4546 } 4547 return unary_complex_lvalue 4548 (code, build2 (COMPOUND_EXPR, TREE_TYPE (lvalue), arg, lvalue)); 4549 } 4550 4551 if (code != ADDR_EXPR) 4552 return NULL_TREE; 4553 4554 /* Handle (a = b) used as an "lvalue" for `&'. */ 4555 if (TREE_CODE (arg) == MODIFY_EXPR 4556 || TREE_CODE (arg) == INIT_EXPR) 4557 { 4558 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 0), 0); 4559 arg = build2 (COMPOUND_EXPR, TREE_TYPE (real_result), 4560 arg, real_result); 4561 TREE_NO_WARNING (arg) = 1; 4562 return arg; 4563 } 4564 4565 if (TREE_CODE (TREE_TYPE (arg)) == FUNCTION_TYPE 4566 || TREE_CODE (TREE_TYPE (arg)) == METHOD_TYPE 4567 || TREE_CODE (arg) == OFFSET_REF) 4568 return NULL_TREE; 4569 4570 /* We permit compiler to make function calls returning 4571 objects of aggregate type look like lvalues. */ 4572 { 4573 tree targ = arg; 4574 4575 if (TREE_CODE (targ) == SAVE_EXPR) 4576 targ = TREE_OPERAND (targ, 0); 4577 4578 if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (TREE_TYPE (targ))) 4579 { 4580 if (TREE_CODE (arg) == SAVE_EXPR) 4581 targ = arg; 4582 else 4583 targ = build_cplus_new (TREE_TYPE (arg), arg); 4584 return build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (arg)), targ); 4585 } 4586 4587 if (TREE_CODE (arg) == SAVE_EXPR && TREE_CODE (targ) == INDIRECT_REF) 4588 return build3 (SAVE_EXPR, build_pointer_type (TREE_TYPE (arg)), 4589 TREE_OPERAND (targ, 0), current_function_decl, NULL); 4590 } 4591 4592 /* Don't let anything else be handled specially. */ 4593 return NULL_TREE; 4594} 4595 4596/* Mark EXP saying that we need to be able to take the 4597 address of it; it should not be allocated in a register. 4598 Value is true if successful. 4599 4600 C++: we do not allow `current_class_ptr' to be addressable. */ 4601 4602bool 4603cxx_mark_addressable (tree exp) 4604{ 4605 tree x = exp; 4606 4607 while (1) 4608 switch (TREE_CODE (x)) 4609 { 4610 case ADDR_EXPR: 4611 case COMPONENT_REF: 4612 case ARRAY_REF: 4613 case REALPART_EXPR: 4614 case IMAGPART_EXPR: 4615 x = TREE_OPERAND (x, 0); 4616 break; 4617 4618 case PARM_DECL: 4619 if (x == current_class_ptr) 4620 { 4621 error ("cannot take the address of %<this%>, which is an rvalue expression"); 4622 TREE_ADDRESSABLE (x) = 1; /* so compiler doesn't die later. */ 4623 return true; 4624 } 4625 /* Fall through. */ 4626 4627 case VAR_DECL: 4628 /* Caller should not be trying to mark initialized 4629 constant fields addressable. */ 4630 gcc_assert (DECL_LANG_SPECIFIC (x) == 0 4631 || DECL_IN_AGGR_P (x) == 0 4632 || TREE_STATIC (x) 4633 || DECL_EXTERNAL (x)); 4634 /* Fall through. */ 4635 4636 case CONST_DECL: 4637 case RESULT_DECL: 4638 if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x) 4639 && !DECL_ARTIFICIAL (x)) 4640 { 4641 if (TREE_CODE (x) == VAR_DECL && DECL_HARD_REGISTER (x)) 4642 { 4643 error 4644 ("address of explicit register variable %qD requested", x); 4645 return false; 4646 } 4647 else if (extra_warnings) 4648 warning 4649 (OPT_Wextra, "address requested for %qD, which is declared %<register%>", x); 4650 } 4651 TREE_ADDRESSABLE (x) = 1; 4652 return true; 4653 4654 case FUNCTION_DECL: 4655 TREE_ADDRESSABLE (x) = 1; 4656 return true; 4657 4658 case CONSTRUCTOR: 4659 TREE_ADDRESSABLE (x) = 1; 4660 return true; 4661 4662 case TARGET_EXPR: 4663 TREE_ADDRESSABLE (x) = 1; 4664 cxx_mark_addressable (TREE_OPERAND (x, 0)); 4665 return true; 4666 4667 default: 4668 return true; 4669 } 4670} 4671 4672/* Build and return a conditional expression IFEXP ? OP1 : OP2. */ 4673 4674tree 4675build_x_conditional_expr (tree ifexp, tree op1, tree op2) 4676{ 4677 tree orig_ifexp = ifexp; 4678 tree orig_op1 = op1; 4679 tree orig_op2 = op2; 4680 tree expr; 4681 4682 if (processing_template_decl) 4683 { 4684 /* The standard says that the expression is type-dependent if 4685 IFEXP is type-dependent, even though the eventual type of the 4686 expression doesn't dependent on IFEXP. */ 4687 if (type_dependent_expression_p (ifexp) 4688 /* As a GNU extension, the middle operand may be omitted. */ 4689 || (op1 && type_dependent_expression_p (op1)) 4690 || type_dependent_expression_p (op2)) 4691 return build_min_nt (COND_EXPR, ifexp, op1, op2); 4692 ifexp = build_non_dependent_expr (ifexp); 4693 if (op1) 4694 op1 = build_non_dependent_expr (op1); 4695 op2 = build_non_dependent_expr (op2); 4696 } 4697 4698 expr = build_conditional_expr (ifexp, op1, op2); 4699 if (processing_template_decl && expr != error_mark_node) 4700 return build_min_non_dep (COND_EXPR, expr, 4701 orig_ifexp, orig_op1, orig_op2); 4702 return expr; 4703} 4704 4705/* Given a list of expressions, return a compound expression 4706 that performs them all and returns the value of the last of them. */ 4707 4708tree build_x_compound_expr_from_list (tree list, const char *msg) 4709{ 4710 tree expr = TREE_VALUE (list); 4711 4712 if (TREE_CHAIN (list)) 4713 { 4714 if (msg) 4715 pedwarn ("%s expression list treated as compound expression", msg); 4716 4717 for (list = TREE_CHAIN (list); list; list = TREE_CHAIN (list)) 4718 expr = build_x_compound_expr (expr, TREE_VALUE (list)); 4719 } 4720 4721 return expr; 4722} 4723 4724/* Handle overloading of the ',' operator when needed. */ 4725 4726tree 4727build_x_compound_expr (tree op1, tree op2) 4728{ 4729 tree result; 4730 tree orig_op1 = op1; 4731 tree orig_op2 = op2; 4732 4733 if (processing_template_decl) 4734 { 4735 if (type_dependent_expression_p (op1) 4736 || type_dependent_expression_p (op2)) 4737 return build_min_nt (COMPOUND_EXPR, op1, op2); 4738 op1 = build_non_dependent_expr (op1); 4739 op2 = build_non_dependent_expr (op2); 4740 } 4741 4742 result = build_new_op (COMPOUND_EXPR, LOOKUP_NORMAL, op1, op2, NULL_TREE, 4743 /*overloaded_p=*/NULL); 4744 if (!result) 4745 result = build_compound_expr (op1, op2); 4746 4747 if (processing_template_decl && result != error_mark_node) 4748 return build_min_non_dep (COMPOUND_EXPR, result, orig_op1, orig_op2); 4749 4750 return result; 4751} 4752 4753/* Build a compound expression. */ 4754 4755tree 4756build_compound_expr (tree lhs, tree rhs) 4757{ 4758 lhs = convert_to_void (lhs, "left-hand operand of comma"); 4759 4760 if (lhs == error_mark_node || rhs == error_mark_node) 4761 return error_mark_node; 4762 4763 if (TREE_CODE (rhs) == TARGET_EXPR) 4764 { 4765 /* If the rhs is a TARGET_EXPR, then build the compound 4766 expression inside the target_expr's initializer. This 4767 helps the compiler to eliminate unnecessary temporaries. */ 4768 tree init = TREE_OPERAND (rhs, 1); 4769 4770 init = build2 (COMPOUND_EXPR, TREE_TYPE (init), lhs, init); 4771 TREE_OPERAND (rhs, 1) = init; 4772 4773 return rhs; 4774 } 4775 4776 return build2 (COMPOUND_EXPR, TREE_TYPE (rhs), lhs, rhs); 4777} 4778 4779/* Issue a diagnostic message if casting from SRC_TYPE to DEST_TYPE 4780 casts away constness. DIAG_FN gives the function to call if we 4781 need to issue a diagnostic; if it is NULL, no diagnostic will be 4782 issued. DESCRIPTION explains what operation is taking place. */ 4783 4784static void 4785check_for_casting_away_constness (tree src_type, tree dest_type, 4786 void (*diag_fn)(const char *, ...) ATTRIBUTE_GCC_CXXDIAG(1,2), 4787 const char *description) 4788{ 4789 if (diag_fn && casts_away_constness (src_type, dest_type)) 4790 diag_fn ("%s from type %qT to type %qT casts away constness", 4791 description, src_type, dest_type); 4792} 4793 4794/* Convert EXPR (an expression with pointer-to-member type) to TYPE 4795 (another pointer-to-member type in the same hierarchy) and return 4796 the converted expression. If ALLOW_INVERSE_P is permitted, a 4797 pointer-to-derived may be converted to pointer-to-base; otherwise, 4798 only the other direction is permitted. If C_CAST_P is true, this 4799 conversion is taking place as part of a C-style cast. */ 4800 4801tree 4802convert_ptrmem (tree type, tree expr, bool allow_inverse_p, 4803 bool c_cast_p) 4804{ 4805 if (TYPE_PTRMEM_P (type)) 4806 { 4807 tree delta; 4808 4809 if (TREE_CODE (expr) == PTRMEM_CST) 4810 expr = cplus_expand_constant (expr); 4811 delta = get_delta_difference (TYPE_PTRMEM_CLASS_TYPE (TREE_TYPE (expr)), 4812 TYPE_PTRMEM_CLASS_TYPE (type), 4813 allow_inverse_p, 4814 c_cast_p); 4815 if (!integer_zerop (delta)) 4816 expr = cp_build_binary_op (PLUS_EXPR, 4817 build_nop (ptrdiff_type_node, expr), 4818 delta); 4819 return build_nop (type, expr); 4820 } 4821 else 4822 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 4823 allow_inverse_p, c_cast_p); 4824} 4825 4826/* If EXPR is an INTEGER_CST and ORIG is an arithmetic constant, return 4827 a version of EXPR that has TREE_OVERFLOW and/or TREE_CONSTANT_OVERFLOW 4828 set iff they are set in ORIG. Otherwise, return EXPR unchanged. */ 4829 4830static tree 4831ignore_overflows (tree expr, tree orig) 4832{ 4833 if (TREE_CODE (expr) == INTEGER_CST 4834 && CONSTANT_CLASS_P (orig) 4835 && TREE_CODE (orig) != STRING_CST 4836 && (TREE_OVERFLOW (expr) != TREE_OVERFLOW (orig) 4837 || TREE_CONSTANT_OVERFLOW (expr) 4838 != TREE_CONSTANT_OVERFLOW (orig))) 4839 { 4840 if (!TREE_OVERFLOW (orig) && !TREE_CONSTANT_OVERFLOW (orig)) 4841 /* Ensure constant sharing. */ 4842 expr = build_int_cst_wide (TREE_TYPE (expr), 4843 TREE_INT_CST_LOW (expr), 4844 TREE_INT_CST_HIGH (expr)); 4845 else 4846 { 4847 /* Avoid clobbering a shared constant. */ 4848 expr = copy_node (expr); 4849 TREE_OVERFLOW (expr) = TREE_OVERFLOW (orig); 4850 TREE_CONSTANT_OVERFLOW (expr) 4851 = TREE_CONSTANT_OVERFLOW (orig); 4852 } 4853 } 4854 return expr; 4855} 4856 4857/* Perform a static_cast from EXPR to TYPE. When C_CAST_P is true, 4858 this static_cast is being attempted as one of the possible casts 4859 allowed by a C-style cast. (In that case, accessibility of base 4860 classes is not considered, and it is OK to cast away 4861 constness.) Return the result of the cast. *VALID_P is set to 4862 indicate whether or not the cast was valid. */ 4863 4864static tree 4865build_static_cast_1 (tree type, tree expr, bool c_cast_p, 4866 bool *valid_p) 4867{ 4868 tree intype; 4869 tree result; 4870 tree orig; 4871 void (*diag_fn)(const char*, ...) ATTRIBUTE_GCC_CXXDIAG(1,2); 4872 const char *desc; 4873 4874 /* Assume the cast is valid. */ 4875 *valid_p = true; 4876 4877 intype = TREE_TYPE (expr); 4878 4879 /* Save casted types in the function's used types hash table. */ 4880 used_types_insert (type); 4881 4882 /* Determine what to do when casting away constness. */ 4883 if (c_cast_p) 4884 { 4885 /* C-style casts are allowed to cast away constness. With 4886 WARN_CAST_QUAL, we still want to issue a warning. */ 4887 diag_fn = warn_cast_qual ? warning0 : NULL; 4888 desc = "cast"; 4889 } 4890 else 4891 { 4892 /* A static_cast may not cast away constness. */ 4893 diag_fn = error; 4894 desc = "static_cast"; 4895 } 4896 4897 /* [expr.static.cast] 4898 4899 An lvalue of type "cv1 B", where B is a class type, can be cast 4900 to type "reference to cv2 D", where D is a class derived (clause 4901 _class.derived_) from B, if a valid standard conversion from 4902 "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the 4903 same cv-qualification as, or greater cv-qualification than, cv1, 4904 and B is not a virtual base class of D. */ 4905 /* We check this case before checking the validity of "TYPE t = 4906 EXPR;" below because for this case: 4907 4908 struct B {}; 4909 struct D : public B { D(const B&); }; 4910 extern B& b; 4911 void f() { static_cast<const D&>(b); } 4912 4913 we want to avoid constructing a new D. The standard is not 4914 completely clear about this issue, but our interpretation is 4915 consistent with other compilers. */ 4916 if (TREE_CODE (type) == REFERENCE_TYPE 4917 && CLASS_TYPE_P (TREE_TYPE (type)) 4918 && CLASS_TYPE_P (intype) 4919 && real_lvalue_p (expr) 4920 && DERIVED_FROM_P (intype, TREE_TYPE (type)) 4921 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT (intype)), 4922 build_pointer_type (TYPE_MAIN_VARIANT 4923 (TREE_TYPE (type)))) 4924 && (c_cast_p 4925 || at_least_as_qualified_p (TREE_TYPE (type), intype))) 4926 { 4927 tree base; 4928 4929 /* There is a standard conversion from "D*" to "B*" even if "B" 4930 is ambiguous or inaccessible. If this is really a 4931 static_cast, then we check both for inaccessibility and 4932 ambiguity. However, if this is a static_cast being performed 4933 because the user wrote a C-style cast, then accessibility is 4934 not considered. */ 4935 base = lookup_base (TREE_TYPE (type), intype, 4936 c_cast_p ? ba_unique : ba_check, 4937 NULL); 4938 4939 /* Convert from "B*" to "D*". This function will check that "B" 4940 is not a virtual base of "D". */ 4941 expr = build_base_path (MINUS_EXPR, build_address (expr), 4942 base, /*nonnull=*/false); 4943 /* Convert the pointer to a reference -- but then remember that 4944 there are no expressions with reference type in C++. */ 4945 return convert_from_reference (build_nop (type, expr)); 4946 } 4947 4948 orig = expr; 4949 4950 /* [expr.static.cast] 4951 4952 An expression e can be explicitly converted to a type T using a 4953 static_cast of the form static_cast<T>(e) if the declaration T 4954 t(e);" is well-formed, for some invented temporary variable 4955 t. */ 4956 result = perform_direct_initialization_if_possible (type, expr, 4957 c_cast_p); 4958 if (result) 4959 { 4960 result = convert_from_reference (result); 4961 4962 /* Ignore any integer overflow caused by the cast. */ 4963 result = ignore_overflows (result, orig); 4964 4965 /* [expr.static.cast] 4966 4967 If T is a reference type, the result is an lvalue; otherwise, 4968 the result is an rvalue. */ 4969 if (TREE_CODE (type) != REFERENCE_TYPE) 4970 result = rvalue (result); 4971 return result; 4972 } 4973 4974 /* [expr.static.cast] 4975 4976 Any expression can be explicitly converted to type cv void. */ 4977 if (TREE_CODE (type) == VOID_TYPE) 4978 return convert_to_void (expr, /*implicit=*/NULL); 4979 4980 /* [expr.static.cast] 4981 4982 The inverse of any standard conversion sequence (clause _conv_), 4983 other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer 4984 (_conv.array_), function-to-pointer (_conv.func_), and boolean 4985 (_conv.bool_) conversions, can be performed explicitly using 4986 static_cast subject to the restriction that the explicit 4987 conversion does not cast away constness (_expr.const.cast_), and 4988 the following additional rules for specific cases: */ 4989 /* For reference, the conversions not excluded are: integral 4990 promotions, floating point promotion, integral conversions, 4991 floating point conversions, floating-integral conversions, 4992 pointer conversions, and pointer to member conversions. */ 4993 /* DR 128 4994 4995 A value of integral _or enumeration_ type can be explicitly 4996 converted to an enumeration type. */ 4997 /* The effect of all that is that any conversion between any two 4998 types which are integral, floating, or enumeration types can be 4999 performed. */ 5000 if ((INTEGRAL_TYPE_P (type) || SCALAR_FLOAT_TYPE_P (type)) 5001 && (INTEGRAL_TYPE_P (intype) || SCALAR_FLOAT_TYPE_P (intype))) 5002 { 5003 expr = ocp_convert (type, expr, CONV_C_CAST, LOOKUP_NORMAL); 5004 5005 /* Ignore any integer overflow caused by the cast. */ 5006 expr = ignore_overflows (expr, orig); 5007 return expr; 5008 } 5009 5010 if (TYPE_PTR_P (type) && TYPE_PTR_P (intype) 5011 && CLASS_TYPE_P (TREE_TYPE (type)) 5012 && CLASS_TYPE_P (TREE_TYPE (intype)) 5013 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT 5014 (TREE_TYPE (intype))), 5015 build_pointer_type (TYPE_MAIN_VARIANT 5016 (TREE_TYPE (type))))) 5017 { 5018 tree base; 5019 5020 if (!c_cast_p) 5021 check_for_casting_away_constness (intype, type, diag_fn, desc); 5022 base = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), 5023 c_cast_p ? ba_unique : ba_check, 5024 NULL); 5025 return build_base_path (MINUS_EXPR, expr, base, /*nonnull=*/false); 5026 } 5027 5028 if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) 5029 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) 5030 { 5031 tree c1; 5032 tree c2; 5033 tree t1; 5034 tree t2; 5035 5036 c1 = TYPE_PTRMEM_CLASS_TYPE (intype); 5037 c2 = TYPE_PTRMEM_CLASS_TYPE (type); 5038 5039 if (TYPE_PTRMEM_P (type)) 5040 { 5041 t1 = (build_ptrmem_type 5042 (c1, 5043 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (intype)))); 5044 t2 = (build_ptrmem_type 5045 (c2, 5046 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (type)))); 5047 } 5048 else 5049 { 5050 t1 = intype; 5051 t2 = type; 5052 } 5053 if (can_convert (t1, t2)) 5054 { 5055 if (!c_cast_p) 5056 check_for_casting_away_constness (intype, type, diag_fn, 5057 desc); 5058 return convert_ptrmem (type, expr, /*allow_inverse_p=*/1, 5059 c_cast_p); 5060 } 5061 } 5062 5063 /* [expr.static.cast] 5064 5065 An rvalue of type "pointer to cv void" can be explicitly 5066 converted to a pointer to object type. A value of type pointer 5067 to object converted to "pointer to cv void" and back to the 5068 original pointer type will have its original value. */ 5069 if (TREE_CODE (intype) == POINTER_TYPE 5070 && VOID_TYPE_P (TREE_TYPE (intype)) 5071 && TYPE_PTROB_P (type)) 5072 { 5073 if (!c_cast_p) 5074 check_for_casting_away_constness (intype, type, diag_fn, desc); 5075 return build_nop (type, expr); 5076 } 5077 5078 *valid_p = false; 5079 return error_mark_node; 5080} 5081 5082/* Return an expression representing static_cast<TYPE>(EXPR). */ 5083 5084tree 5085build_static_cast (tree type, tree expr) 5086{ 5087 tree result; 5088 bool valid_p; 5089 5090 if (type == error_mark_node || expr == error_mark_node) 5091 return error_mark_node; 5092 5093 if (processing_template_decl) 5094 { 5095 expr = build_min (STATIC_CAST_EXPR, type, expr); 5096 /* We don't know if it will or will not have side effects. */ 5097 TREE_SIDE_EFFECTS (expr) = 1; 5098 return convert_from_reference (expr); 5099 } 5100 5101 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 5102 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 5103 if (TREE_CODE (type) != REFERENCE_TYPE 5104 && TREE_CODE (expr) == NOP_EXPR 5105 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 5106 expr = TREE_OPERAND (expr, 0); 5107 5108 result = build_static_cast_1 (type, expr, /*c_cast_p=*/false, &valid_p); 5109 if (valid_p) 5110 return result; 5111 5112 error ("invalid static_cast from type %qT to type %qT", 5113 TREE_TYPE (expr), type); 5114 return error_mark_node; 5115} 5116 5117/* EXPR is an expression with member function or pointer-to-member 5118 function type. TYPE is a pointer type. Converting EXPR to TYPE is 5119 not permitted by ISO C++, but we accept it in some modes. If we 5120 are not in one of those modes, issue a diagnostic. Return the 5121 converted expression. */ 5122 5123tree 5124convert_member_func_to_ptr (tree type, tree expr) 5125{ 5126 tree intype; 5127 tree decl; 5128 5129 intype = TREE_TYPE (expr); 5130 gcc_assert (TYPE_PTRMEMFUNC_P (intype) 5131 || TREE_CODE (intype) == METHOD_TYPE); 5132 5133 if (pedantic || warn_pmf2ptr) 5134 pedwarn ("converting from %qT to %qT", intype, type); 5135 5136 if (TREE_CODE (intype) == METHOD_TYPE) 5137 expr = build_addr_func (expr); 5138 else if (TREE_CODE (expr) == PTRMEM_CST) 5139 expr = build_address (PTRMEM_CST_MEMBER (expr)); 5140 else 5141 { 5142 decl = maybe_dummy_object (TYPE_PTRMEM_CLASS_TYPE (intype), 0); 5143 decl = build_address (decl); 5144 expr = get_member_function_from_ptrfunc (&decl, expr); 5145 } 5146 5147 return build_nop (type, expr); 5148} 5149 5150/* Return a representation for a reinterpret_cast from EXPR to TYPE. 5151 If C_CAST_P is true, this reinterpret cast is being done as part of 5152 a C-style cast. If VALID_P is non-NULL, *VALID_P is set to 5153 indicate whether or not reinterpret_cast was valid. */ 5154 5155static tree 5156build_reinterpret_cast_1 (tree type, tree expr, bool c_cast_p, 5157 bool *valid_p) 5158{ 5159 tree intype; 5160 5161 /* Assume the cast is invalid. */ 5162 if (valid_p) 5163 *valid_p = true; 5164 5165 if (type == error_mark_node || error_operand_p (expr)) 5166 return error_mark_node; 5167 5168 intype = TREE_TYPE (expr); 5169 5170 /* Save casted types in the function's used types hash table. */ 5171 used_types_insert (type); 5172 5173 /* [expr.reinterpret.cast] 5174 An lvalue expression of type T1 can be cast to the type 5175 "reference to T2" if an expression of type "pointer to T1" can be 5176 explicitly converted to the type "pointer to T2" using a 5177 reinterpret_cast. */ 5178 if (TREE_CODE (type) == REFERENCE_TYPE) 5179 { 5180 if (! real_lvalue_p (expr)) 5181 { 5182 error ("invalid cast of an rvalue expression of type " 5183 "%qT to type %qT", 5184 intype, type); 5185 return error_mark_node; 5186 } 5187 5188 /* Warn about a reinterpret_cast from "A*" to "B&" if "A" and 5189 "B" are related class types; the reinterpret_cast does not 5190 adjust the pointer. */ 5191 if (TYPE_PTR_P (intype) 5192 && (comptypes (TREE_TYPE (intype), TREE_TYPE (type), 5193 COMPARE_BASE | COMPARE_DERIVED))) 5194 warning (0, "casting %qT to %qT does not dereference pointer", 5195 intype, type); 5196 5197 expr = build_unary_op (ADDR_EXPR, expr, 0); 5198 if (expr != error_mark_node) 5199 expr = build_reinterpret_cast_1 5200 (build_pointer_type (TREE_TYPE (type)), expr, c_cast_p, 5201 valid_p); 5202 if (expr != error_mark_node) 5203 expr = build_indirect_ref (expr, 0); 5204 return expr; 5205 } 5206 5207 /* As a G++ extension, we consider conversions from member 5208 functions, and pointers to member functions to 5209 pointer-to-function and pointer-to-void types. If 5210 -Wno-pmf-conversions has not been specified, 5211 convert_member_func_to_ptr will issue an error message. */ 5212 if ((TYPE_PTRMEMFUNC_P (intype) 5213 || TREE_CODE (intype) == METHOD_TYPE) 5214 && TYPE_PTR_P (type) 5215 && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE 5216 || VOID_TYPE_P (TREE_TYPE (type)))) 5217 return convert_member_func_to_ptr (type, expr); 5218 5219 /* If the cast is not to a reference type, the lvalue-to-rvalue, 5220 array-to-pointer, and function-to-pointer conversions are 5221 performed. */ 5222 expr = decay_conversion (expr); 5223 5224 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 5225 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 5226 if (TREE_CODE (expr) == NOP_EXPR 5227 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 5228 expr = TREE_OPERAND (expr, 0); 5229 5230 if (error_operand_p (expr)) 5231 return error_mark_node; 5232 5233 intype = TREE_TYPE (expr); 5234 5235 /* [expr.reinterpret.cast] 5236 A pointer can be converted to any integral type large enough to 5237 hold it. */ 5238 if (CP_INTEGRAL_TYPE_P (type) && TYPE_PTR_P (intype)) 5239 { 5240 if (TYPE_PRECISION (type) < TYPE_PRECISION (intype)) 5241 pedwarn ("cast from %qT to %qT loses precision", 5242 intype, type); 5243 } 5244 /* [expr.reinterpret.cast] 5245 A value of integral or enumeration type can be explicitly 5246 converted to a pointer. */ 5247 else if (TYPE_PTR_P (type) && INTEGRAL_OR_ENUMERATION_TYPE_P (intype)) 5248 /* OK */ 5249 ; 5250 else if ((TYPE_PTRFN_P (type) && TYPE_PTRFN_P (intype)) 5251 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) 5252 return fold_if_not_in_template (build_nop (type, expr)); 5253 else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) 5254 || (TYPE_PTROBV_P (type) && TYPE_PTROBV_P (intype))) 5255 { 5256 tree sexpr = expr; 5257 5258 if (!c_cast_p) 5259 check_for_casting_away_constness (intype, type, error, 5260 "reinterpret_cast"); 5261 /* Warn about possible alignment problems. */ 5262 if (STRICT_ALIGNMENT && warn_cast_align 5263 && !VOID_TYPE_P (type) 5264 && TREE_CODE (TREE_TYPE (intype)) != FUNCTION_TYPE 5265 && COMPLETE_TYPE_P (TREE_TYPE (type)) 5266 && COMPLETE_TYPE_P (TREE_TYPE (intype)) 5267 && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (intype))) 5268 warning (0, "cast from %qT to %qT increases required alignment of " 5269 "target type", 5270 intype, type); 5271 5272 /* We need to strip nops here, because the frontend likes to 5273 create (int *)&a for array-to-pointer decay, instead of &a[0]. */ 5274 STRIP_NOPS (sexpr); 5275 if (warn_strict_aliasing <= 2) 5276 strict_aliasing_warning (intype, type, sexpr); 5277 5278 return fold_if_not_in_template (build_nop (type, expr)); 5279 } 5280 else if ((TYPE_PTRFN_P (type) && TYPE_PTROBV_P (intype)) 5281 || (TYPE_PTRFN_P (intype) && TYPE_PTROBV_P (type))) 5282 { 5283 if (pedantic) 5284 /* Only issue a warning, as we have always supported this 5285 where possible, and it is necessary in some cases. DR 195 5286 addresses this issue, but as of 2004/10/26 is still in 5287 drafting. */ 5288 warning (0, "ISO C++ forbids casting between pointer-to-function and pointer-to-object"); 5289 return fold_if_not_in_template (build_nop (type, expr)); 5290 } 5291 else if (TREE_CODE (type) == VECTOR_TYPE) 5292 return fold_if_not_in_template (convert_to_vector (type, expr)); 5293 else if (TREE_CODE (intype) == VECTOR_TYPE && INTEGRAL_TYPE_P (type)) 5294 return fold_if_not_in_template (convert_to_integer (type, expr)); 5295 else 5296 { 5297 if (valid_p) 5298 *valid_p = false; 5299 error ("invalid cast from type %qT to type %qT", intype, type); 5300 return error_mark_node; 5301 } 5302 5303 return cp_convert (type, expr); 5304} 5305 5306tree 5307build_reinterpret_cast (tree type, tree expr) 5308{ 5309 if (type == error_mark_node || expr == error_mark_node) 5310 return error_mark_node; 5311 5312 if (processing_template_decl) 5313 { 5314 tree t = build_min (REINTERPRET_CAST_EXPR, type, expr); 5315 5316 if (!TREE_SIDE_EFFECTS (t) 5317 && type_dependent_expression_p (expr)) 5318 /* There might turn out to be side effects inside expr. */ 5319 TREE_SIDE_EFFECTS (t) = 1; 5320 return convert_from_reference (t); 5321 } 5322 5323 return build_reinterpret_cast_1 (type, expr, /*c_cast_p=*/false, 5324 /*valid_p=*/NULL); 5325} 5326 5327/* Perform a const_cast from EXPR to TYPE. If the cast is valid, 5328 return an appropriate expression. Otherwise, return 5329 error_mark_node. If the cast is not valid, and COMPLAIN is true, 5330 then a diagnostic will be issued. If VALID_P is non-NULL, we are 5331 performing a C-style cast, its value upon return will indicate 5332 whether or not the conversion succeeded. */ 5333 5334static tree 5335build_const_cast_1 (tree dst_type, tree expr, bool complain, 5336 bool *valid_p) 5337{ 5338 tree src_type; 5339 tree reference_type; 5340 5341 /* Callers are responsible for handling error_mark_node as a 5342 destination type. */ 5343 gcc_assert (dst_type != error_mark_node); 5344 /* In a template, callers should be building syntactic 5345 representations of casts, not using this machinery. */ 5346 gcc_assert (!processing_template_decl); 5347 5348 /* Assume the conversion is invalid. */ 5349 if (valid_p) 5350 *valid_p = false; 5351 5352 if (!POINTER_TYPE_P (dst_type) && !TYPE_PTRMEM_P (dst_type)) 5353 { 5354 if (complain) 5355 error ("invalid use of const_cast with type %qT, " 5356 "which is not a pointer, " 5357 "reference, nor a pointer-to-data-member type", dst_type); 5358 return error_mark_node; 5359 } 5360 5361 if (TREE_CODE (TREE_TYPE (dst_type)) == FUNCTION_TYPE) 5362 { 5363 if (complain) 5364 error ("invalid use of const_cast with type %qT, which is a pointer " 5365 "or reference to a function type", dst_type); 5366 return error_mark_node; 5367 } 5368 5369 /* Save casted types in the function's used types hash table. */ 5370 used_types_insert (dst_type); 5371 5372 src_type = TREE_TYPE (expr); 5373 /* Expressions do not really have reference types. */ 5374 if (TREE_CODE (src_type) == REFERENCE_TYPE) 5375 src_type = TREE_TYPE (src_type); 5376 5377 /* [expr.const.cast] 5378 5379 An lvalue of type T1 can be explicitly converted to an lvalue of 5380 type T2 using the cast const_cast<T2&> (where T1 and T2 are object 5381 types) if a pointer to T1 can be explicitly converted to the type 5382 pointer to T2 using a const_cast. */ 5383 if (TREE_CODE (dst_type) == REFERENCE_TYPE) 5384 { 5385 reference_type = dst_type; 5386 if (! real_lvalue_p (expr)) 5387 { 5388 if (complain) 5389 error ("invalid const_cast of an rvalue of type %qT to type %qT", 5390 src_type, dst_type); 5391 return error_mark_node; 5392 } 5393 dst_type = build_pointer_type (TREE_TYPE (dst_type)); 5394 src_type = build_pointer_type (src_type); 5395 } 5396 else 5397 { 5398 reference_type = NULL_TREE; 5399 /* If the destination type is not a reference type, the 5400 lvalue-to-rvalue, array-to-pointer, and function-to-pointer 5401 conversions are performed. */ 5402 src_type = type_decays_to (src_type); 5403 if (src_type == error_mark_node) 5404 return error_mark_node; 5405 } 5406 5407 if ((TYPE_PTR_P (src_type) || TYPE_PTRMEM_P (src_type)) 5408 && comp_ptr_ttypes_const (dst_type, src_type)) 5409 { 5410 if (valid_p) 5411 { 5412 *valid_p = true; 5413 /* This cast is actually a C-style cast. Issue a warning if 5414 the user is making a potentially unsafe cast. */ 5415 if (warn_cast_qual) 5416 check_for_casting_away_constness (src_type, dst_type, 5417 warning0, 5418 "cast"); 5419 } 5420 if (reference_type) 5421 { 5422 expr = build_unary_op (ADDR_EXPR, expr, 0); 5423 expr = build_nop (reference_type, expr); 5424 return convert_from_reference (expr); 5425 } 5426 else 5427 { 5428 expr = decay_conversion (expr); 5429 /* build_c_cast puts on a NOP_EXPR to make the result not an 5430 lvalue. Strip such NOP_EXPRs if VALUE is being used in 5431 non-lvalue context. */ 5432 if (TREE_CODE (expr) == NOP_EXPR 5433 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 5434 expr = TREE_OPERAND (expr, 0); 5435 return build_nop (dst_type, expr); 5436 } 5437 } 5438 5439 if (complain) 5440 error ("invalid const_cast from type %qT to type %qT", 5441 src_type, dst_type); 5442 return error_mark_node; 5443} 5444 5445tree 5446build_const_cast (tree type, tree expr) 5447{ 5448 if (type == error_mark_node || error_operand_p (expr)) 5449 return error_mark_node; 5450 5451 if (processing_template_decl) 5452 { 5453 tree t = build_min (CONST_CAST_EXPR, type, expr); 5454 5455 if (!TREE_SIDE_EFFECTS (t) 5456 && type_dependent_expression_p (expr)) 5457 /* There might turn out to be side effects inside expr. */ 5458 TREE_SIDE_EFFECTS (t) = 1; 5459 return convert_from_reference (t); 5460 } 5461 5462 return build_const_cast_1 (type, expr, /*complain=*/true, 5463 /*valid_p=*/NULL); 5464} 5465 5466/* Build an expression representing an explicit C-style cast to type 5467 TYPE of expression EXPR. */ 5468 5469tree 5470build_c_cast (tree type, tree expr) 5471{ 5472 tree value = expr; 5473 tree result; 5474 bool valid_p; 5475 5476 if (type == error_mark_node || error_operand_p (expr)) 5477 return error_mark_node; 5478 5479 if (processing_template_decl) 5480 { 5481 tree t = build_min (CAST_EXPR, type, 5482 tree_cons (NULL_TREE, value, NULL_TREE)); 5483 /* We don't know if it will or will not have side effects. */ 5484 TREE_SIDE_EFFECTS (t) = 1; 5485 return convert_from_reference (t); 5486 } 5487 5488 /* Casts to a (pointer to a) specific ObjC class (or 'id' or 5489 'Class') should always be retained, because this information aids 5490 in method lookup. */ 5491 if (objc_is_object_ptr (type) 5492 && objc_is_object_ptr (TREE_TYPE (expr))) 5493 return build_nop (type, expr); 5494 5495 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 5496 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 5497 if (TREE_CODE (type) != REFERENCE_TYPE 5498 && TREE_CODE (value) == NOP_EXPR 5499 && TREE_TYPE (value) == TREE_TYPE (TREE_OPERAND (value, 0))) 5500 value = TREE_OPERAND (value, 0); 5501 5502 if (TREE_CODE (type) == ARRAY_TYPE) 5503 { 5504 /* Allow casting from T1* to T2[] because Cfront allows it. 5505 NIHCL uses it. It is not valid ISO C++ however. */ 5506 if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) 5507 { 5508 pedwarn ("ISO C++ forbids casting to an array type %qT", type); 5509 type = build_pointer_type (TREE_TYPE (type)); 5510 } 5511 else 5512 { 5513 error ("ISO C++ forbids casting to an array type %qT", type); 5514 return error_mark_node; 5515 } 5516 } 5517 5518 if (TREE_CODE (type) == FUNCTION_TYPE 5519 || TREE_CODE (type) == METHOD_TYPE) 5520 { 5521 error ("invalid cast to function type %qT", type); 5522 return error_mark_node; 5523 } 5524 5525 /* A C-style cast can be a const_cast. */ 5526 result = build_const_cast_1 (type, value, /*complain=*/false, 5527 &valid_p); 5528 if (valid_p) 5529 return result; 5530 5531 /* Or a static cast. */ 5532 result = build_static_cast_1 (type, value, /*c_cast_p=*/true, 5533 &valid_p); 5534 /* Or a reinterpret_cast. */ 5535 if (!valid_p) 5536 result = build_reinterpret_cast_1 (type, value, /*c_cast_p=*/true, 5537 &valid_p); 5538 /* The static_cast or reinterpret_cast may be followed by a 5539 const_cast. */ 5540 if (valid_p 5541 /* A valid cast may result in errors if, for example, a 5542 conversion to am ambiguous base class is required. */ 5543 && !error_operand_p (result)) 5544 { 5545 tree result_type; 5546 5547 /* Non-class rvalues always have cv-unqualified type. */ 5548 if (!CLASS_TYPE_P (type)) 5549 type = TYPE_MAIN_VARIANT (type); 5550 result_type = TREE_TYPE (result); 5551 if (!CLASS_TYPE_P (result_type)) 5552 result_type = TYPE_MAIN_VARIANT (result_type); 5553 /* If the type of RESULT does not match TYPE, perform a 5554 const_cast to make it match. If the static_cast or 5555 reinterpret_cast succeeded, we will differ by at most 5556 cv-qualification, so the follow-on const_cast is guaranteed 5557 to succeed. */ 5558 if (!same_type_p (non_reference (type), non_reference (result_type))) 5559 { 5560 result = build_const_cast_1 (type, result, false, &valid_p); 5561 gcc_assert (valid_p); 5562 } 5563 return result; 5564 } 5565 5566 return error_mark_node; 5567} 5568 5569/* Build an assignment expression of lvalue LHS from value RHS. 5570 MODIFYCODE is the code for a binary operator that we use 5571 to combine the old value of LHS with RHS to get the new value. 5572 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment. 5573 5574 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */ 5575 5576tree 5577build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs) 5578{ 5579 tree result; 5580 tree newrhs = rhs; 5581 tree lhstype = TREE_TYPE (lhs); 5582 tree olhstype = lhstype; 5583 tree olhs = NULL_TREE; 5584 bool plain_assign = (modifycode == NOP_EXPR); 5585 5586 /* Avoid duplicate error messages from operands that had errors. */ 5587 if (error_operand_p (lhs) || error_operand_p (rhs)) 5588 return error_mark_node; 5589 5590 /* Handle control structure constructs used as "lvalues". */ 5591 switch (TREE_CODE (lhs)) 5592 { 5593 /* Handle --foo = 5; as these are valid constructs in C++. */ 5594 case PREDECREMENT_EXPR: 5595 case PREINCREMENT_EXPR: 5596 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0))) 5597 lhs = build2 (TREE_CODE (lhs), TREE_TYPE (lhs), 5598 stabilize_reference (TREE_OPERAND (lhs, 0)), 5599 TREE_OPERAND (lhs, 1)); 5600 return build2 (COMPOUND_EXPR, lhstype, 5601 lhs, 5602 build_modify_expr (TREE_OPERAND (lhs, 0), 5603 modifycode, rhs)); 5604 5605 /* Handle (a, b) used as an "lvalue". */ 5606 case COMPOUND_EXPR: 5607 newrhs = build_modify_expr (TREE_OPERAND (lhs, 1), 5608 modifycode, rhs); 5609 if (newrhs == error_mark_node) 5610 return error_mark_node; 5611 return build2 (COMPOUND_EXPR, lhstype, 5612 TREE_OPERAND (lhs, 0), newrhs); 5613 5614 case MODIFY_EXPR: 5615 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0))) 5616 lhs = build2 (TREE_CODE (lhs), TREE_TYPE (lhs), 5617 stabilize_reference (TREE_OPERAND (lhs, 0)), 5618 TREE_OPERAND (lhs, 1)); 5619 newrhs = build_modify_expr (TREE_OPERAND (lhs, 0), modifycode, rhs); 5620 if (newrhs == error_mark_node) 5621 return error_mark_node; 5622 return build2 (COMPOUND_EXPR, lhstype, lhs, newrhs); 5623 5624 case MIN_EXPR: 5625 case MAX_EXPR: 5626 /* MIN_EXPR and MAX_EXPR are currently only permitted as lvalues, 5627 when neither operand has side-effects. */ 5628 if (!lvalue_or_else (lhs, lv_assign)) 5629 return error_mark_node; 5630 5631 gcc_assert (!TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)) 5632 && !TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 1))); 5633 5634 lhs = build3 (COND_EXPR, TREE_TYPE (lhs), 5635 build2 (TREE_CODE (lhs) == MIN_EXPR ? LE_EXPR : GE_EXPR, 5636 boolean_type_node, 5637 TREE_OPERAND (lhs, 0), 5638 TREE_OPERAND (lhs, 1)), 5639 TREE_OPERAND (lhs, 0), 5640 TREE_OPERAND (lhs, 1)); 5641 /* Fall through. */ 5642 5643 /* Handle (a ? b : c) used as an "lvalue". */ 5644 case COND_EXPR: 5645 { 5646 /* Produce (a ? (b = rhs) : (c = rhs)) 5647 except that the RHS goes through a save-expr 5648 so the code to compute it is only emitted once. */ 5649 tree cond; 5650 tree preeval = NULL_TREE; 5651 5652 if (VOID_TYPE_P (TREE_TYPE (rhs))) 5653 { 5654 error ("void value not ignored as it ought to be"); 5655 return error_mark_node; 5656 } 5657 5658 rhs = stabilize_expr (rhs, &preeval); 5659 5660 /* Check this here to avoid odd errors when trying to convert 5661 a throw to the type of the COND_EXPR. */ 5662 if (!lvalue_or_else (lhs, lv_assign)) 5663 return error_mark_node; 5664 5665 cond = build_conditional_expr 5666 (TREE_OPERAND (lhs, 0), 5667 build_modify_expr (TREE_OPERAND (lhs, 1), 5668 modifycode, rhs), 5669 build_modify_expr (TREE_OPERAND (lhs, 2), 5670 modifycode, rhs)); 5671 5672 if (cond == error_mark_node) 5673 return cond; 5674 /* Make sure the code to compute the rhs comes out 5675 before the split. */ 5676 if (preeval) 5677 cond = build2 (COMPOUND_EXPR, TREE_TYPE (lhs), preeval, cond); 5678 return cond; 5679 } 5680 5681 default: 5682 break; 5683 } 5684 5685 if (modifycode == INIT_EXPR) 5686 { 5687 if (TREE_CODE (rhs) == CONSTRUCTOR) 5688 { 5689 if (! same_type_p (TREE_TYPE (rhs), lhstype)) 5690 /* Call convert to generate an error; see PR 11063. */ 5691 rhs = convert (lhstype, rhs); 5692 result = build2 (INIT_EXPR, lhstype, lhs, rhs); 5693 TREE_SIDE_EFFECTS (result) = 1; 5694 return result; 5695 } 5696 else if (! IS_AGGR_TYPE (lhstype)) 5697 /* Do the default thing. */; 5698 else 5699 { 5700 result = build_special_member_call (lhs, complete_ctor_identifier, 5701 build_tree_list (NULL_TREE, rhs), 5702 lhstype, LOOKUP_NORMAL); 5703 if (result == NULL_TREE) 5704 return error_mark_node; 5705 return result; 5706 } 5707 } 5708 else 5709 { 5710 lhs = require_complete_type (lhs); 5711 if (lhs == error_mark_node) 5712 return error_mark_node; 5713 5714 if (modifycode == NOP_EXPR) 5715 { 5716 /* `operator=' is not an inheritable operator. */ 5717 if (! IS_AGGR_TYPE (lhstype)) 5718 /* Do the default thing. */; 5719 else 5720 { 5721 result = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, 5722 lhs, rhs, make_node (NOP_EXPR), 5723 /*overloaded_p=*/NULL); 5724 if (result == NULL_TREE) 5725 return error_mark_node; 5726 return result; 5727 } 5728 lhstype = olhstype; 5729 } 5730 else 5731 { 5732 /* A binary op has been requested. Combine the old LHS 5733 value with the RHS producing the value we should actually 5734 store into the LHS. */ 5735 5736 gcc_assert (!PROMOTES_TO_AGGR_TYPE (lhstype, REFERENCE_TYPE)); 5737 lhs = stabilize_reference (lhs); 5738 newrhs = cp_build_binary_op (modifycode, lhs, rhs); 5739 if (newrhs == error_mark_node) 5740 { 5741 error (" in evaluation of %<%Q(%#T, %#T)%>", modifycode, 5742 TREE_TYPE (lhs), TREE_TYPE (rhs)); 5743 return error_mark_node; 5744 } 5745 5746 /* Now it looks like a plain assignment. */ 5747 modifycode = NOP_EXPR; 5748 } 5749 gcc_assert (TREE_CODE (lhstype) != REFERENCE_TYPE); 5750 gcc_assert (TREE_CODE (TREE_TYPE (newrhs)) != REFERENCE_TYPE); 5751 } 5752 5753 /* The left-hand side must be an lvalue. */ 5754 if (!lvalue_or_else (lhs, lv_assign)) 5755 return error_mark_node; 5756 5757 /* Warn about modifying something that is `const'. Don't warn if 5758 this is initialization. */ 5759 if (modifycode != INIT_EXPR 5760 && (TREE_READONLY (lhs) || CP_TYPE_CONST_P (lhstype) 5761 /* Functions are not modifiable, even though they are 5762 lvalues. */ 5763 || TREE_CODE (TREE_TYPE (lhs)) == FUNCTION_TYPE 5764 || TREE_CODE (TREE_TYPE (lhs)) == METHOD_TYPE 5765 /* If it's an aggregate and any field is const, then it is 5766 effectively const. */ 5767 || (CLASS_TYPE_P (lhstype) 5768 && C_TYPE_FIELDS_READONLY (lhstype)))) 5769 readonly_error (lhs, "assignment", 0); 5770 5771 /* If storing into a structure or union member, it has probably been 5772 given type `int'. Compute the type that would go with the actual 5773 amount of storage the member occupies. */ 5774 5775 if (TREE_CODE (lhs) == COMPONENT_REF 5776 && (TREE_CODE (lhstype) == INTEGER_TYPE 5777 || TREE_CODE (lhstype) == REAL_TYPE 5778 || TREE_CODE (lhstype) == ENUMERAL_TYPE)) 5779 { 5780 lhstype = TREE_TYPE (get_unwidened (lhs, 0)); 5781 5782 /* If storing in a field that is in actuality a short or narrower 5783 than one, we must store in the field in its actual type. */ 5784 5785 if (lhstype != TREE_TYPE (lhs)) 5786 { 5787 /* Avoid warnings converting integral types back into enums for 5788 enum bit fields. */ 5789 if (TREE_CODE (lhstype) == INTEGER_TYPE 5790 && TREE_CODE (olhstype) == ENUMERAL_TYPE) 5791 { 5792 if (TREE_SIDE_EFFECTS (lhs)) 5793 lhs = stabilize_reference (lhs); 5794 olhs = lhs; 5795 } 5796 lhs = copy_node (lhs); 5797 TREE_TYPE (lhs) = lhstype; 5798 } 5799 } 5800 5801 /* Convert new value to destination type. */ 5802 5803 if (TREE_CODE (lhstype) == ARRAY_TYPE) 5804 { 5805 int from_array; 5806 5807 if (!same_or_base_type_p (TYPE_MAIN_VARIANT (lhstype), 5808 TYPE_MAIN_VARIANT (TREE_TYPE (rhs)))) 5809 { 5810 error ("incompatible types in assignment of %qT to %qT", 5811 TREE_TYPE (rhs), lhstype); 5812 return error_mark_node; 5813 } 5814 5815 /* Allow array assignment in compiler-generated code. */ 5816 if (! DECL_ARTIFICIAL (current_function_decl)) 5817 { 5818 /* This routine is used for both initialization and assignment. 5819 Make sure the diagnostic message differentiates the context. */ 5820 if (modifycode == INIT_EXPR) 5821 error ("array used as initializer"); 5822 else 5823 error ("invalid array assignment"); 5824 return error_mark_node; 5825 } 5826 5827 from_array = TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE 5828 ? 1 + (modifycode != INIT_EXPR): 0; 5829 return build_vec_init (lhs, NULL_TREE, newrhs, 5830 /*explicit_default_init_p=*/false, 5831 from_array); 5832 } 5833 5834 if (modifycode == INIT_EXPR) 5835 newrhs = convert_for_initialization (lhs, lhstype, newrhs, LOOKUP_NORMAL, 5836 "initialization", NULL_TREE, 0); 5837 else 5838 { 5839 /* Avoid warnings on enum bit fields. */ 5840 if (TREE_CODE (olhstype) == ENUMERAL_TYPE 5841 && TREE_CODE (lhstype) == INTEGER_TYPE) 5842 { 5843 newrhs = convert_for_assignment (olhstype, newrhs, "assignment", 5844 NULL_TREE, 0); 5845 newrhs = convert_force (lhstype, newrhs, 0); 5846 } 5847 else 5848 newrhs = convert_for_assignment (lhstype, newrhs, "assignment", 5849 NULL_TREE, 0); 5850 if (TREE_CODE (newrhs) == CALL_EXPR 5851 && TYPE_NEEDS_CONSTRUCTING (lhstype)) 5852 newrhs = build_cplus_new (lhstype, newrhs); 5853 5854 /* Can't initialize directly from a TARGET_EXPR, since that would 5855 cause the lhs to be constructed twice, and possibly result in 5856 accidental self-initialization. So we force the TARGET_EXPR to be 5857 expanded without a target. */ 5858 if (TREE_CODE (newrhs) == TARGET_EXPR) 5859 newrhs = build2 (COMPOUND_EXPR, TREE_TYPE (newrhs), newrhs, 5860 TREE_OPERAND (newrhs, 0)); 5861 } 5862 5863 if (newrhs == error_mark_node) 5864 return error_mark_node; 5865 5866 if (c_dialect_objc () && flag_objc_gc) 5867 { 5868 result = objc_generate_write_barrier (lhs, modifycode, newrhs); 5869 5870 if (result) 5871 return result; 5872 } 5873 5874 result = build2 (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR, 5875 lhstype, lhs, newrhs); 5876 5877 TREE_SIDE_EFFECTS (result) = 1; 5878 if (!plain_assign) 5879 TREE_NO_WARNING (result) = 1; 5880 5881 /* If we got the LHS in a different type for storing in, 5882 convert the result back to the nominal type of LHS 5883 so that the value we return always has the same type 5884 as the LHS argument. */ 5885 5886 if (olhstype == TREE_TYPE (result)) 5887 return result; 5888 if (olhs) 5889 { 5890 result = build2 (COMPOUND_EXPR, olhstype, result, olhs); 5891 TREE_NO_WARNING (result) = 1; 5892 return result; 5893 } 5894 return convert_for_assignment (olhstype, result, "assignment", 5895 NULL_TREE, 0); 5896} 5897 5898tree 5899build_x_modify_expr (tree lhs, enum tree_code modifycode, tree rhs) 5900{ 5901 if (processing_template_decl) 5902 return build_min_nt (MODOP_EXPR, lhs, 5903 build_min_nt (modifycode, NULL_TREE, NULL_TREE), rhs); 5904 5905 if (modifycode != NOP_EXPR) 5906 { 5907 tree rval = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, lhs, rhs, 5908 make_node (modifycode), 5909 /*overloaded_p=*/NULL); 5910 if (rval) 5911 { 5912 TREE_NO_WARNING (rval) = 1; 5913 return rval; 5914 } 5915 } 5916 return build_modify_expr (lhs, modifycode, rhs); 5917} 5918 5919 5920/* Get difference in deltas for different pointer to member function 5921 types. Returns an integer constant of type PTRDIFF_TYPE_NODE. If 5922 the conversion is invalid, the constant is zero. If 5923 ALLOW_INVERSE_P is true, then allow reverse conversions as well. 5924 If C_CAST_P is true this conversion is taking place as part of a 5925 C-style cast. 5926 5927 Note that the naming of FROM and TO is kind of backwards; the return 5928 value is what we add to a TO in order to get a FROM. They are named 5929 this way because we call this function to find out how to convert from 5930 a pointer to member of FROM to a pointer to member of TO. */ 5931 5932static tree 5933get_delta_difference (tree from, tree to, 5934 bool allow_inverse_p, 5935 bool c_cast_p) 5936{ 5937 tree binfo; 5938 base_kind kind; 5939 tree result; 5940 5941 /* Assume no conversion is required. */ 5942 result = integer_zero_node; 5943 binfo = lookup_base (to, from, c_cast_p ? ba_unique : ba_check, &kind); 5944 if (kind == bk_inaccessible || kind == bk_ambig) 5945 error (" in pointer to member function conversion"); 5946 else if (binfo) 5947 { 5948 if (kind != bk_via_virtual) 5949 result = BINFO_OFFSET (binfo); 5950 else 5951 { 5952 tree virt_binfo = binfo_from_vbase (binfo); 5953 5954 /* This is a reinterpret cast, we choose to do nothing. */ 5955 if (allow_inverse_p) 5956 warning (0, "pointer to member cast via virtual base %qT", 5957 BINFO_TYPE (virt_binfo)); 5958 else 5959 error ("pointer to member conversion via virtual base %qT", 5960 BINFO_TYPE (virt_binfo)); 5961 } 5962 } 5963 else if (same_type_ignoring_top_level_qualifiers_p (from, to)) 5964 /* Pointer to member of incomplete class is permitted*/; 5965 else if (!allow_inverse_p) 5966 { 5967 error_not_base_type (from, to); 5968 error (" in pointer to member conversion"); 5969 } 5970 else 5971 { 5972 binfo = lookup_base (from, to, c_cast_p ? ba_unique : ba_check, &kind); 5973 if (binfo) 5974 { 5975 if (kind != bk_via_virtual) 5976 result = size_diffop (size_zero_node, BINFO_OFFSET (binfo)); 5977 else 5978 { 5979 /* This is a reinterpret cast, we choose to do nothing. */ 5980 tree virt_binfo = binfo_from_vbase (binfo); 5981 5982 warning (0, "pointer to member cast via virtual base %qT", 5983 BINFO_TYPE (virt_binfo)); 5984 } 5985 } 5986 } 5987 5988 return fold_if_not_in_template (convert_to_integer (ptrdiff_type_node, 5989 result)); 5990} 5991 5992/* Return a constructor for the pointer-to-member-function TYPE using 5993 the other components as specified. */ 5994 5995tree 5996build_ptrmemfunc1 (tree type, tree delta, tree pfn) 5997{ 5998 tree u = NULL_TREE; 5999 tree delta_field; 6000 tree pfn_field; 6001 VEC(constructor_elt, gc) *v; 6002 6003 /* Pull the FIELD_DECLs out of the type. */ 6004 pfn_field = TYPE_FIELDS (type); 6005 delta_field = TREE_CHAIN (pfn_field); 6006 6007 /* Make sure DELTA has the type we want. */ 6008 delta = convert_and_check (delta_type_node, delta); 6009 6010 /* Finish creating the initializer. */ 6011 v = VEC_alloc(constructor_elt, gc, 2); 6012 CONSTRUCTOR_APPEND_ELT(v, pfn_field, pfn); 6013 CONSTRUCTOR_APPEND_ELT(v, delta_field, delta); 6014 u = build_constructor (type, v); 6015 TREE_CONSTANT (u) = TREE_CONSTANT (pfn) & TREE_CONSTANT (delta); 6016 TREE_INVARIANT (u) = TREE_INVARIANT (pfn) & TREE_INVARIANT (delta); 6017 TREE_STATIC (u) = (TREE_CONSTANT (u) 6018 && (initializer_constant_valid_p (pfn, TREE_TYPE (pfn)) 6019 != NULL_TREE) 6020 && (initializer_constant_valid_p (delta, TREE_TYPE (delta)) 6021 != NULL_TREE)); 6022 return u; 6023} 6024 6025/* Build a constructor for a pointer to member function. It can be 6026 used to initialize global variables, local variable, or used 6027 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we 6028 want to be. 6029 6030 If FORCE is nonzero, then force this conversion, even if 6031 we would rather not do it. Usually set when using an explicit 6032 cast. A C-style cast is being processed iff C_CAST_P is true. 6033 6034 Return error_mark_node, if something goes wrong. */ 6035 6036tree 6037build_ptrmemfunc (tree type, tree pfn, int force, bool c_cast_p) 6038{ 6039 tree fn; 6040 tree pfn_type; 6041 tree to_type; 6042 6043 if (error_operand_p (pfn)) 6044 return error_mark_node; 6045 6046 pfn_type = TREE_TYPE (pfn); 6047 to_type = build_ptrmemfunc_type (type); 6048 6049 /* Handle multiple conversions of pointer to member functions. */ 6050 if (TYPE_PTRMEMFUNC_P (pfn_type)) 6051 { 6052 tree delta = NULL_TREE; 6053 tree npfn = NULL_TREE; 6054 tree n; 6055 6056 if (!force 6057 && !can_convert_arg (to_type, TREE_TYPE (pfn), pfn, LOOKUP_NORMAL)) 6058 error ("invalid conversion to type %qT from type %qT", 6059 to_type, pfn_type); 6060 6061 n = get_delta_difference (TYPE_PTRMEMFUNC_OBJECT_TYPE (pfn_type), 6062 TYPE_PTRMEMFUNC_OBJECT_TYPE (to_type), 6063 force, 6064 c_cast_p); 6065 6066 /* We don't have to do any conversion to convert a 6067 pointer-to-member to its own type. But, we don't want to 6068 just return a PTRMEM_CST if there's an explicit cast; that 6069 cast should make the expression an invalid template argument. */ 6070 if (TREE_CODE (pfn) != PTRMEM_CST) 6071 { 6072 if (same_type_p (to_type, pfn_type)) 6073 return pfn; 6074 else if (integer_zerop (n)) 6075 return build_reinterpret_cast (to_type, pfn); 6076 } 6077 6078 if (TREE_SIDE_EFFECTS (pfn)) 6079 pfn = save_expr (pfn); 6080 6081 /* Obtain the function pointer and the current DELTA. */ 6082 if (TREE_CODE (pfn) == PTRMEM_CST) 6083 expand_ptrmemfunc_cst (pfn, &delta, &npfn); 6084 else 6085 { 6086 npfn = build_ptrmemfunc_access_expr (pfn, pfn_identifier); 6087 delta = build_ptrmemfunc_access_expr (pfn, delta_identifier); 6088 } 6089 6090 /* Just adjust the DELTA field. */ 6091 gcc_assert (same_type_ignoring_top_level_qualifiers_p 6092 (TREE_TYPE (delta), ptrdiff_type_node)); 6093 if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_delta) 6094 n = cp_build_binary_op (LSHIFT_EXPR, n, integer_one_node); 6095 delta = cp_build_binary_op (PLUS_EXPR, delta, n); 6096 return build_ptrmemfunc1 (to_type, delta, npfn); 6097 } 6098 6099 /* Handle null pointer to member function conversions. */ 6100 if (integer_zerop (pfn)) 6101 { 6102 pfn = build_c_cast (type, integer_zero_node); 6103 return build_ptrmemfunc1 (to_type, 6104 integer_zero_node, 6105 pfn); 6106 } 6107 6108 if (type_unknown_p (pfn)) 6109 return instantiate_type (type, pfn, tf_warning_or_error); 6110 6111 fn = TREE_OPERAND (pfn, 0); 6112 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL 6113 /* In a template, we will have preserved the 6114 OFFSET_REF. */ 6115 || (processing_template_decl && TREE_CODE (fn) == OFFSET_REF)); 6116 return make_ptrmem_cst (to_type, fn); 6117} 6118 6119/* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST 6120 given by CST. 6121 6122 ??? There is no consistency as to the types returned for the above 6123 values. Some code acts as if it were a sizetype and some as if it were 6124 integer_type_node. */ 6125 6126void 6127expand_ptrmemfunc_cst (tree cst, tree *delta, tree *pfn) 6128{ 6129 tree type = TREE_TYPE (cst); 6130 tree fn = PTRMEM_CST_MEMBER (cst); 6131 tree ptr_class, fn_class; 6132 6133 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL); 6134 6135 /* The class that the function belongs to. */ 6136 fn_class = DECL_CONTEXT (fn); 6137 6138 /* The class that we're creating a pointer to member of. */ 6139 ptr_class = TYPE_PTRMEMFUNC_OBJECT_TYPE (type); 6140 6141 /* First, calculate the adjustment to the function's class. */ 6142 *delta = get_delta_difference (fn_class, ptr_class, /*force=*/0, 6143 /*c_cast_p=*/0); 6144 6145 if (!DECL_VIRTUAL_P (fn)) 6146 *pfn = convert (TYPE_PTRMEMFUNC_FN_TYPE (type), build_addr_func (fn)); 6147 else 6148 { 6149 /* If we're dealing with a virtual function, we have to adjust 'this' 6150 again, to point to the base which provides the vtable entry for 6151 fn; the call will do the opposite adjustment. */ 6152 tree orig_class = DECL_CONTEXT (fn); 6153 tree binfo = binfo_or_else (orig_class, fn_class); 6154 *delta = build2 (PLUS_EXPR, TREE_TYPE (*delta), 6155 *delta, BINFO_OFFSET (binfo)); 6156 *delta = fold_if_not_in_template (*delta); 6157 6158 /* We set PFN to the vtable offset at which the function can be 6159 found, plus one (unless ptrmemfunc_vbit_in_delta, in which 6160 case delta is shifted left, and then incremented). */ 6161 *pfn = DECL_VINDEX (fn); 6162 *pfn = build2 (MULT_EXPR, integer_type_node, *pfn, 6163 TYPE_SIZE_UNIT (vtable_entry_type)); 6164 *pfn = fold_if_not_in_template (*pfn); 6165 6166 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION) 6167 { 6168 case ptrmemfunc_vbit_in_pfn: 6169 *pfn = build2 (PLUS_EXPR, integer_type_node, *pfn, 6170 integer_one_node); 6171 *pfn = fold_if_not_in_template (*pfn); 6172 break; 6173 6174 case ptrmemfunc_vbit_in_delta: 6175 *delta = build2 (LSHIFT_EXPR, TREE_TYPE (*delta), 6176 *delta, integer_one_node); 6177 *delta = fold_if_not_in_template (*delta); 6178 *delta = build2 (PLUS_EXPR, TREE_TYPE (*delta), 6179 *delta, integer_one_node); 6180 *delta = fold_if_not_in_template (*delta); 6181 break; 6182 6183 default: 6184 gcc_unreachable (); 6185 } 6186 6187 *pfn = build_nop (TYPE_PTRMEMFUNC_FN_TYPE (type), *pfn); 6188 *pfn = fold_if_not_in_template (*pfn); 6189 } 6190} 6191 6192/* Return an expression for PFN from the pointer-to-member function 6193 given by T. */ 6194 6195static tree 6196pfn_from_ptrmemfunc (tree t) 6197{ 6198 if (TREE_CODE (t) == PTRMEM_CST) 6199 { 6200 tree delta; 6201 tree pfn; 6202 6203 expand_ptrmemfunc_cst (t, &delta, &pfn); 6204 if (pfn) 6205 return pfn; 6206 } 6207 6208 return build_ptrmemfunc_access_expr (t, pfn_identifier); 6209} 6210 6211/* Convert value RHS to type TYPE as preparation for an assignment to 6212 an lvalue of type TYPE. ERRTYPE is a string to use in error 6213 messages: "assignment", "return", etc. If FNDECL is non-NULL, we 6214 are doing the conversion in order to pass the PARMNUMth argument of 6215 FNDECL. */ 6216 6217static tree 6218convert_for_assignment (tree type, tree rhs, 6219 const char *errtype, tree fndecl, int parmnum) 6220{ 6221 tree rhstype; 6222 enum tree_code coder; 6223 6224 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */ 6225 if (TREE_CODE (rhs) == NON_LVALUE_EXPR) 6226 rhs = TREE_OPERAND (rhs, 0); 6227 6228 rhstype = TREE_TYPE (rhs); 6229 coder = TREE_CODE (rhstype); 6230 6231 if (TREE_CODE (type) == VECTOR_TYPE && coder == VECTOR_TYPE 6232 && vector_types_convertible_p (type, rhstype)) 6233 return convert (type, rhs); 6234 6235 if (rhs == error_mark_node || rhstype == error_mark_node) 6236 return error_mark_node; 6237 if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node) 6238 return error_mark_node; 6239 6240 /* The RHS of an assignment cannot have void type. */ 6241 if (coder == VOID_TYPE) 6242 { 6243 error ("void value not ignored as it ought to be"); 6244 return error_mark_node; 6245 } 6246 6247 /* Simplify the RHS if possible. */ 6248 if (TREE_CODE (rhs) == CONST_DECL) 6249 rhs = DECL_INITIAL (rhs); 6250 6251 if (c_dialect_objc ()) 6252 { 6253 int parmno; 6254 tree rname = fndecl; 6255 6256 if (!strcmp (errtype, "assignment")) 6257 parmno = -1; 6258 else if (!strcmp (errtype, "initialization")) 6259 parmno = -2; 6260 else 6261 { 6262 tree selector = objc_message_selector (); 6263 6264 parmno = parmnum; 6265 6266 if (selector && parmno > 1) 6267 { 6268 rname = selector; 6269 parmno -= 1; 6270 } 6271 } 6272 6273 if (objc_compare_types (type, rhstype, parmno, rname)) 6274 return convert (type, rhs); 6275 } 6276 6277 /* [expr.ass] 6278 6279 The expression is implicitly converted (clause _conv_) to the 6280 cv-unqualified type of the left operand. 6281 6282 We allow bad conversions here because by the time we get to this point 6283 we are committed to doing the conversion. If we end up doing a bad 6284 conversion, convert_like will complain. */ 6285 if (!can_convert_arg_bad (type, rhstype, rhs)) 6286 { 6287 /* When -Wno-pmf-conversions is use, we just silently allow 6288 conversions from pointers-to-members to plain pointers. If 6289 the conversion doesn't work, cp_convert will complain. */ 6290 if (!warn_pmf2ptr 6291 && TYPE_PTR_P (type) 6292 && TYPE_PTRMEMFUNC_P (rhstype)) 6293 rhs = cp_convert (strip_top_quals (type), rhs); 6294 else 6295 { 6296 /* If the right-hand side has unknown type, then it is an 6297 overloaded function. Call instantiate_type to get error 6298 messages. */ 6299 if (rhstype == unknown_type_node) 6300 instantiate_type (type, rhs, tf_warning_or_error); 6301 else if (fndecl) 6302 error ("cannot convert %qT to %qT for argument %qP to %qD", 6303 rhstype, type, parmnum, fndecl); 6304 else 6305 error ("cannot convert %qT to %qT in %s", rhstype, type, errtype); 6306 return error_mark_node; 6307 } 6308 } 6309 if (warn_missing_format_attribute) 6310 { 6311 const enum tree_code codel = TREE_CODE (type); 6312 if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE) 6313 && coder == codel 6314 && check_missing_format_attribute (type, rhstype)) 6315 warning (OPT_Wmissing_format_attribute, 6316 "%s might be a candidate for a format attribute", 6317 errtype); 6318 } 6319 6320 /* If -Wparentheses, warn about a = b = c when a has type bool and b 6321 does not. */ 6322 if (warn_parentheses 6323 && type == boolean_type_node 6324 && TREE_CODE (rhs) == MODIFY_EXPR 6325 && !TREE_NO_WARNING (rhs) 6326 && TREE_TYPE (rhs) != boolean_type_node) 6327 { 6328 warning (OPT_Wparentheses, 6329 "suggest parentheses around assignment used as truth value"); 6330 TREE_NO_WARNING (rhs) = 1; 6331 } 6332 6333 return perform_implicit_conversion (strip_top_quals (type), rhs); 6334} 6335 6336/* Convert RHS to be of type TYPE. 6337 If EXP is nonzero, it is the target of the initialization. 6338 ERRTYPE is a string to use in error messages. 6339 6340 Two major differences between the behavior of 6341 `convert_for_assignment' and `convert_for_initialization' 6342 are that references are bashed in the former, while 6343 copied in the latter, and aggregates are assigned in 6344 the former (operator=) while initialized in the 6345 latter (X(X&)). 6346 6347 If using constructor make sure no conversion operator exists, if one does 6348 exist, an ambiguity exists. 6349 6350 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */ 6351 6352tree 6353convert_for_initialization (tree exp, tree type, tree rhs, int flags, 6354 const char *errtype, tree fndecl, int parmnum) 6355{ 6356 enum tree_code codel = TREE_CODE (type); 6357 tree rhstype; 6358 enum tree_code coder; 6359 6360 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 6361 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */ 6362 if (TREE_CODE (rhs) == NOP_EXPR 6363 && TREE_TYPE (rhs) == TREE_TYPE (TREE_OPERAND (rhs, 0)) 6364 && codel != REFERENCE_TYPE) 6365 rhs = TREE_OPERAND (rhs, 0); 6366 6367 if (type == error_mark_node 6368 || rhs == error_mark_node 6369 || (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)) 6370 return error_mark_node; 6371 6372 if ((TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE 6373 && TREE_CODE (type) != ARRAY_TYPE 6374 && (TREE_CODE (type) != REFERENCE_TYPE 6375 || TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE)) 6376 || (TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE 6377 && (TREE_CODE (type) != REFERENCE_TYPE 6378 || TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)) 6379 || TREE_CODE (TREE_TYPE (rhs)) == METHOD_TYPE) 6380 rhs = decay_conversion (rhs); 6381 6382 rhstype = TREE_TYPE (rhs); 6383 coder = TREE_CODE (rhstype); 6384 6385 if (coder == ERROR_MARK) 6386 return error_mark_node; 6387 6388 /* We accept references to incomplete types, so we can 6389 return here before checking if RHS is of complete type. */ 6390 6391 if (codel == REFERENCE_TYPE) 6392 { 6393 /* This should eventually happen in convert_arguments. */ 6394 int savew = 0, savee = 0; 6395 6396 if (fndecl) 6397 savew = warningcount, savee = errorcount; 6398 rhs = initialize_reference (type, rhs, /*decl=*/NULL_TREE, 6399 /*cleanup=*/NULL); 6400 if (fndecl) 6401 { 6402 if (warningcount > savew) 6403 warning (0, "in passing argument %P of %q+D", parmnum, fndecl); 6404 else if (errorcount > savee) 6405 error ("in passing argument %P of %q+D", parmnum, fndecl); 6406 } 6407 return rhs; 6408 } 6409 6410 if (exp != 0) 6411 exp = require_complete_type (exp); 6412 if (exp == error_mark_node) 6413 return error_mark_node; 6414 6415 rhstype = non_reference (rhstype); 6416 6417 type = complete_type (type); 6418 6419 if (IS_AGGR_TYPE (type)) 6420 return ocp_convert (type, rhs, CONV_IMPLICIT|CONV_FORCE_TEMP, flags); 6421 6422 return convert_for_assignment (type, rhs, errtype, fndecl, parmnum); 6423} 6424 6425/* If RETVAL is the address of, or a reference to, a local variable or 6426 temporary give an appropriate warning. */ 6427 6428static void 6429maybe_warn_about_returning_address_of_local (tree retval) 6430{ 6431 tree valtype = TREE_TYPE (DECL_RESULT (current_function_decl)); 6432 tree whats_returned = retval; 6433 6434 for (;;) 6435 { 6436 if (TREE_CODE (whats_returned) == COMPOUND_EXPR) 6437 whats_returned = TREE_OPERAND (whats_returned, 1); 6438 else if (TREE_CODE (whats_returned) == CONVERT_EXPR 6439 || TREE_CODE (whats_returned) == NON_LVALUE_EXPR 6440 || TREE_CODE (whats_returned) == NOP_EXPR) 6441 whats_returned = TREE_OPERAND (whats_returned, 0); 6442 else 6443 break; 6444 } 6445 6446 if (TREE_CODE (whats_returned) != ADDR_EXPR) 6447 return; 6448 whats_returned = TREE_OPERAND (whats_returned, 0); 6449 6450 if (TREE_CODE (valtype) == REFERENCE_TYPE) 6451 { 6452 if (TREE_CODE (whats_returned) == AGGR_INIT_EXPR 6453 || TREE_CODE (whats_returned) == TARGET_EXPR) 6454 { 6455 warning (0, "returning reference to temporary"); 6456 return; 6457 } 6458 if (TREE_CODE (whats_returned) == VAR_DECL 6459 && DECL_NAME (whats_returned) 6460 && TEMP_NAME_P (DECL_NAME (whats_returned))) 6461 { 6462 warning (0, "reference to non-lvalue returned"); 6463 return; 6464 } 6465 } 6466 6467 while (TREE_CODE (whats_returned) == COMPONENT_REF 6468 || TREE_CODE (whats_returned) == ARRAY_REF) 6469 whats_returned = TREE_OPERAND (whats_returned, 0); 6470 6471 if (DECL_P (whats_returned) 6472 && DECL_NAME (whats_returned) 6473 && DECL_FUNCTION_SCOPE_P (whats_returned) 6474 && !(TREE_STATIC (whats_returned) 6475 || TREE_PUBLIC (whats_returned))) 6476 { 6477 if (TREE_CODE (valtype) == REFERENCE_TYPE) 6478 warning (0, "reference to local variable %q+D returned", 6479 whats_returned); 6480 else 6481 warning (0, "address of local variable %q+D returned", 6482 whats_returned); 6483 return; 6484 } 6485} 6486 6487/* Check that returning RETVAL from the current function is valid. 6488 Return an expression explicitly showing all conversions required to 6489 change RETVAL into the function return type, and to assign it to 6490 the DECL_RESULT for the function. Set *NO_WARNING to true if 6491 code reaches end of non-void function warning shouldn't be issued 6492 on this RETURN_EXPR. */ 6493 6494tree 6495check_return_expr (tree retval, bool *no_warning) 6496{ 6497 tree result; 6498 /* The type actually returned by the function, after any 6499 promotions. */ 6500 tree valtype; 6501 int fn_returns_value_p; 6502 6503 *no_warning = false; 6504 6505 /* A `volatile' function is one that isn't supposed to return, ever. 6506 (This is a G++ extension, used to get better code for functions 6507 that call the `volatile' function.) */ 6508 if (TREE_THIS_VOLATILE (current_function_decl)) 6509 warning (0, "function declared %<noreturn%> has a %<return%> statement"); 6510 6511 /* Check for various simple errors. */ 6512 if (DECL_DESTRUCTOR_P (current_function_decl)) 6513 { 6514 if (retval) 6515 error ("returning a value from a destructor"); 6516 return NULL_TREE; 6517 } 6518 else if (DECL_CONSTRUCTOR_P (current_function_decl)) 6519 { 6520 if (in_function_try_handler) 6521 /* If a return statement appears in a handler of the 6522 function-try-block of a constructor, the program is ill-formed. */ 6523 error ("cannot return from a handler of a function-try-block of a constructor"); 6524 else if (retval) 6525 /* You can't return a value from a constructor. */ 6526 error ("returning a value from a constructor"); 6527 return NULL_TREE; 6528 } 6529 6530 if (processing_template_decl) 6531 { 6532 current_function_returns_value = 1; 6533 return retval; 6534 } 6535 6536 /* When no explicit return-value is given in a function with a named 6537 return value, the named return value is used. */ 6538 result = DECL_RESULT (current_function_decl); 6539 valtype = TREE_TYPE (result); 6540 gcc_assert (valtype != NULL_TREE); 6541 fn_returns_value_p = !VOID_TYPE_P (valtype); 6542 if (!retval && DECL_NAME (result) && fn_returns_value_p) 6543 retval = result; 6544 6545 /* Check for a return statement with no return value in a function 6546 that's supposed to return a value. */ 6547 if (!retval && fn_returns_value_p) 6548 { 6549 pedwarn ("return-statement with no value, in function returning %qT", 6550 valtype); 6551 /* Clear this, so finish_function won't say that we reach the 6552 end of a non-void function (which we don't, we gave a 6553 return!). */ 6554 current_function_returns_null = 0; 6555 /* And signal caller that TREE_NO_WARNING should be set on the 6556 RETURN_EXPR to avoid control reaches end of non-void function 6557 warnings in tree-cfg.c. */ 6558 *no_warning = true; 6559 } 6560 /* Check for a return statement with a value in a function that 6561 isn't supposed to return a value. */ 6562 else if (retval && !fn_returns_value_p) 6563 { 6564 if (VOID_TYPE_P (TREE_TYPE (retval))) 6565 /* You can return a `void' value from a function of `void' 6566 type. In that case, we have to evaluate the expression for 6567 its side-effects. */ 6568 finish_expr_stmt (retval); 6569 else 6570 pedwarn ("return-statement with a value, in function " 6571 "returning 'void'"); 6572 6573 current_function_returns_null = 1; 6574 6575 /* There's really no value to return, after all. */ 6576 return NULL_TREE; 6577 } 6578 else if (!retval) 6579 /* Remember that this function can sometimes return without a 6580 value. */ 6581 current_function_returns_null = 1; 6582 else 6583 /* Remember that this function did return a value. */ 6584 current_function_returns_value = 1; 6585 6586 /* Check for erroneous operands -- but after giving ourselves a 6587 chance to provide an error about returning a value from a void 6588 function. */ 6589 if (error_operand_p (retval)) 6590 { 6591 current_function_return_value = error_mark_node; 6592 return error_mark_node; 6593 } 6594 6595 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */ 6596 if ((DECL_OVERLOADED_OPERATOR_P (current_function_decl) == NEW_EXPR 6597 || DECL_OVERLOADED_OPERATOR_P (current_function_decl) == VEC_NEW_EXPR) 6598 && !TYPE_NOTHROW_P (TREE_TYPE (current_function_decl)) 6599 && ! flag_check_new 6600 && null_ptr_cst_p (retval)) 6601 warning (0, "%<operator new%> must not return NULL unless it is " 6602 "declared %<throw()%> (or -fcheck-new is in effect)"); 6603 6604 /* Effective C++ rule 15. See also start_function. */ 6605 if (warn_ecpp 6606 && DECL_NAME (current_function_decl) == ansi_assopname(NOP_EXPR)) 6607 { 6608 bool warn = true; 6609 6610 /* The function return type must be a reference to the current 6611 class. */ 6612 if (TREE_CODE (valtype) == REFERENCE_TYPE 6613 && same_type_ignoring_top_level_qualifiers_p 6614 (TREE_TYPE (valtype), TREE_TYPE (current_class_ref))) 6615 { 6616 /* Returning '*this' is obviously OK. */ 6617 if (retval == current_class_ref) 6618 warn = false; 6619 /* If we are calling a function whose return type is the same of 6620 the current class reference, it is ok. */ 6621 else if (TREE_CODE (retval) == INDIRECT_REF 6622 && TREE_CODE (TREE_OPERAND (retval, 0)) == CALL_EXPR) 6623 warn = false; 6624 } 6625 6626 if (warn) 6627 warning (OPT_Weffc__, "%<operator=%> should return a reference to %<*this%>"); 6628 } 6629 6630 /* The fabled Named Return Value optimization, as per [class.copy]/15: 6631 6632 [...] For a function with a class return type, if the expression 6633 in the return statement is the name of a local object, and the cv- 6634 unqualified type of the local object is the same as the function 6635 return type, an implementation is permitted to omit creating the tem- 6636 porary object to hold the function return value [...] 6637 6638 So, if this is a value-returning function that always returns the same 6639 local variable, remember it. 6640 6641 It might be nice to be more flexible, and choose the first suitable 6642 variable even if the function sometimes returns something else, but 6643 then we run the risk of clobbering the variable we chose if the other 6644 returned expression uses the chosen variable somehow. And people expect 6645 this restriction, anyway. (jason 2000-11-19) 6646 6647 See finish_function and finalize_nrv for the rest of this optimization. */ 6648 6649 if (fn_returns_value_p && flag_elide_constructors) 6650 { 6651 if (retval != NULL_TREE 6652 && (current_function_return_value == NULL_TREE 6653 || current_function_return_value == retval) 6654 && TREE_CODE (retval) == VAR_DECL 6655 && DECL_CONTEXT (retval) == current_function_decl 6656 && ! TREE_STATIC (retval) 6657 && ! DECL_ANON_UNION_VAR_P (retval) 6658 && (DECL_ALIGN (retval) 6659 >= DECL_ALIGN (DECL_RESULT (current_function_decl))) 6660 && same_type_p ((TYPE_MAIN_VARIANT 6661 (TREE_TYPE (retval))), 6662 (TYPE_MAIN_VARIANT 6663 (TREE_TYPE (TREE_TYPE (current_function_decl)))))) 6664 current_function_return_value = retval; 6665 else 6666 current_function_return_value = error_mark_node; 6667 } 6668 6669 /* We don't need to do any conversions when there's nothing being 6670 returned. */ 6671 if (!retval) 6672 return NULL_TREE; 6673 6674 /* Do any required conversions. */ 6675 if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl)) 6676 /* No conversions are required. */ 6677 ; 6678 else 6679 { 6680 /* The type the function is declared to return. */ 6681 tree functype = TREE_TYPE (TREE_TYPE (current_function_decl)); 6682 6683 /* The functype's return type will have been set to void, if it 6684 was an incomplete type. Just treat this as 'return;' */ 6685 if (VOID_TYPE_P (functype)) 6686 return error_mark_node; 6687 6688 /* First convert the value to the function's return type, then 6689 to the type of return value's location to handle the 6690 case that functype is smaller than the valtype. */ 6691 retval = convert_for_initialization 6692 (NULL_TREE, functype, retval, LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING, 6693 "return", NULL_TREE, 0); 6694 retval = convert (valtype, retval); 6695 6696 /* If the conversion failed, treat this just like `return;'. */ 6697 if (retval == error_mark_node) 6698 return retval; 6699 /* We can't initialize a register from a AGGR_INIT_EXPR. */ 6700 else if (! current_function_returns_struct 6701 && TREE_CODE (retval) == TARGET_EXPR 6702 && TREE_CODE (TREE_OPERAND (retval, 1)) == AGGR_INIT_EXPR) 6703 retval = build2 (COMPOUND_EXPR, TREE_TYPE (retval), retval, 6704 TREE_OPERAND (retval, 0)); 6705 else 6706 maybe_warn_about_returning_address_of_local (retval); 6707 } 6708 6709 /* Actually copy the value returned into the appropriate location. */ 6710 if (retval && retval != result) 6711 retval = build2 (INIT_EXPR, TREE_TYPE (result), result, retval); 6712 6713 return retval; 6714} 6715 6716 6717/* Returns nonzero if the pointer-type FROM can be converted to the 6718 pointer-type TO via a qualification conversion. If CONSTP is -1, 6719 then we return nonzero if the pointers are similar, and the 6720 cv-qualification signature of FROM is a proper subset of that of TO. 6721 6722 If CONSTP is positive, then all outer pointers have been 6723 const-qualified. */ 6724 6725static int 6726comp_ptr_ttypes_real (tree to, tree from, int constp) 6727{ 6728 bool to_more_cv_qualified = false; 6729 6730 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 6731 { 6732 if (TREE_CODE (to) != TREE_CODE (from)) 6733 return 0; 6734 6735 if (TREE_CODE (from) == OFFSET_TYPE 6736 && !same_type_p (TYPE_OFFSET_BASETYPE (from), 6737 TYPE_OFFSET_BASETYPE (to))) 6738 return 0; 6739 6740 /* Const and volatile mean something different for function types, 6741 so the usual checks are not appropriate. */ 6742 if (TREE_CODE (to) != FUNCTION_TYPE && TREE_CODE (to) != METHOD_TYPE) 6743 { 6744 /* In Objective-C++, some types may have been 'volatilized' by 6745 the compiler for EH; when comparing them here, the volatile 6746 qualification must be ignored. */ 6747 bool objc_quals_match = objc_type_quals_match (to, from); 6748 6749 if (!at_least_as_qualified_p (to, from) && !objc_quals_match) 6750 return 0; 6751 6752 if (!at_least_as_qualified_p (from, to) && !objc_quals_match) 6753 { 6754 if (constp == 0) 6755 return 0; 6756 to_more_cv_qualified = true; 6757 } 6758 6759 if (constp > 0) 6760 constp &= TYPE_READONLY (to); 6761 } 6762 6763 if (TREE_CODE (to) != POINTER_TYPE && !TYPE_PTRMEM_P (to)) 6764 return ((constp >= 0 || to_more_cv_qualified) 6765 && same_type_ignoring_top_level_qualifiers_p (to, from)); 6766 } 6767} 6768 6769/* When comparing, say, char ** to char const **, this function takes 6770 the 'char *' and 'char const *'. Do not pass non-pointer/reference 6771 types to this function. */ 6772 6773int 6774comp_ptr_ttypes (tree to, tree from) 6775{ 6776 return comp_ptr_ttypes_real (to, from, 1); 6777} 6778 6779/* Returns 1 if to and from are (possibly multi-level) pointers to the same 6780 type or inheritance-related types, regardless of cv-quals. */ 6781 6782int 6783ptr_reasonably_similar (tree to, tree from) 6784{ 6785 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 6786 { 6787 /* Any target type is similar enough to void. */ 6788 if (TREE_CODE (to) == VOID_TYPE 6789 || TREE_CODE (from) == VOID_TYPE) 6790 return 1; 6791 6792 if (TREE_CODE (to) != TREE_CODE (from)) 6793 return 0; 6794 6795 if (TREE_CODE (from) == OFFSET_TYPE 6796 && comptypes (TYPE_OFFSET_BASETYPE (to), 6797 TYPE_OFFSET_BASETYPE (from), 6798 COMPARE_BASE | COMPARE_DERIVED)) 6799 continue; 6800 6801 if (TREE_CODE (to) == VECTOR_TYPE 6802 && vector_types_convertible_p (to, from)) 6803 return 1; 6804 6805 if (TREE_CODE (to) == INTEGER_TYPE 6806 && TYPE_PRECISION (to) == TYPE_PRECISION (from)) 6807 return 1; 6808 6809 if (TREE_CODE (to) == FUNCTION_TYPE) 6810 return 1; 6811 6812 if (TREE_CODE (to) != POINTER_TYPE) 6813 return comptypes 6814 (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from), 6815 COMPARE_BASE | COMPARE_DERIVED); 6816 } 6817} 6818 6819/* Return true if TO and FROM (both of which are POINTER_TYPEs or 6820 pointer-to-member types) are the same, ignoring cv-qualification at 6821 all levels. */ 6822 6823bool 6824comp_ptr_ttypes_const (tree to, tree from) 6825{ 6826 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 6827 { 6828 if (TREE_CODE (to) != TREE_CODE (from)) 6829 return false; 6830 6831 if (TREE_CODE (from) == OFFSET_TYPE 6832 && same_type_p (TYPE_OFFSET_BASETYPE (from), 6833 TYPE_OFFSET_BASETYPE (to))) 6834 continue; 6835 6836 if (TREE_CODE (to) != POINTER_TYPE) 6837 return same_type_ignoring_top_level_qualifiers_p (to, from); 6838 } 6839} 6840 6841/* Returns the type qualifiers for this type, including the qualifiers on the 6842 elements for an array type. */ 6843 6844int 6845cp_type_quals (tree type) 6846{ 6847 type = strip_array_types (type); 6848 if (type == error_mark_node) 6849 return TYPE_UNQUALIFIED; 6850 return TYPE_QUALS (type); 6851} 6852 6853/* Returns nonzero if the TYPE is const from a C++ perspective: look inside 6854 arrays. */ 6855 6856bool 6857cp_type_readonly (tree type) 6858{ 6859 type = strip_array_types (type); 6860 return TYPE_READONLY (type); 6861} 6862 6863/* Returns nonzero if the TYPE contains a mutable member. */ 6864 6865bool 6866cp_has_mutable_p (tree type) 6867{ 6868 type = strip_array_types (type); 6869 6870 return CLASS_TYPE_P (type) && CLASSTYPE_HAS_MUTABLE (type); 6871} 6872 6873/* Apply the TYPE_QUALS to the new DECL. */ 6874void 6875cp_apply_type_quals_to_decl (int type_quals, tree decl) 6876{ 6877 tree type = TREE_TYPE (decl); 6878 6879 if (type == error_mark_node) 6880 return; 6881 6882 if (TREE_CODE (type) == FUNCTION_TYPE 6883 && type_quals != TYPE_UNQUALIFIED) 6884 { 6885 /* This was an error in C++98 (cv-qualifiers cannot be added to 6886 a function type), but DR 295 makes the code well-formed by 6887 dropping the extra qualifiers. */ 6888 if (pedantic) 6889 { 6890 tree bad_type = build_qualified_type (type, type_quals); 6891 pedwarn ("ignoring %qV qualifiers added to function type %qT", 6892 bad_type, type); 6893 } 6894 6895 TREE_TYPE (decl) = TYPE_MAIN_VARIANT (type); 6896 return; 6897 } 6898 6899 /* Avoid setting TREE_READONLY incorrectly. */ 6900 if (/* If the object has a constructor, the constructor may modify 6901 the object. */ 6902 TYPE_NEEDS_CONSTRUCTING (type) 6903 /* If the type isn't complete, we don't know yet if it will need 6904 constructing. */ 6905 || !COMPLETE_TYPE_P (type) 6906 /* If the type has a mutable component, that component might be 6907 modified. */ 6908 || TYPE_HAS_MUTABLE_P (type)) 6909 type_quals &= ~TYPE_QUAL_CONST; 6910 6911 c_apply_type_quals_to_decl (type_quals, decl); 6912} 6913 6914/* Subroutine of casts_away_constness. Make T1 and T2 point at 6915 exemplar types such that casting T1 to T2 is casting away constness 6916 if and only if there is no implicit conversion from T1 to T2. */ 6917 6918static void 6919casts_away_constness_r (tree *t1, tree *t2) 6920{ 6921 int quals1; 6922 int quals2; 6923 6924 /* [expr.const.cast] 6925 6926 For multi-level pointer to members and multi-level mixed pointers 6927 and pointers to members (conv.qual), the "member" aspect of a 6928 pointer to member level is ignored when determining if a const 6929 cv-qualifier has been cast away. */ 6930 /* [expr.const.cast] 6931 6932 For two pointer types: 6933 6934 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type 6935 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type 6936 K is min(N,M) 6937 6938 casting from X1 to X2 casts away constness if, for a non-pointer 6939 type T there does not exist an implicit conversion (clause 6940 _conv_) from: 6941 6942 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N * 6943 6944 to 6945 6946 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */ 6947 if ((!TYPE_PTR_P (*t1) && !TYPE_PTRMEM_P (*t1)) 6948 || (!TYPE_PTR_P (*t2) && !TYPE_PTRMEM_P (*t2))) 6949 { 6950 *t1 = cp_build_qualified_type (void_type_node, 6951 cp_type_quals (*t1)); 6952 *t2 = cp_build_qualified_type (void_type_node, 6953 cp_type_quals (*t2)); 6954 return; 6955 } 6956 6957 quals1 = cp_type_quals (*t1); 6958 quals2 = cp_type_quals (*t2); 6959 6960 if (TYPE_PTRMEM_P (*t1)) 6961 *t1 = TYPE_PTRMEM_POINTED_TO_TYPE (*t1); 6962 else 6963 *t1 = TREE_TYPE (*t1); 6964 if (TYPE_PTRMEM_P (*t2)) 6965 *t2 = TYPE_PTRMEM_POINTED_TO_TYPE (*t2); 6966 else 6967 *t2 = TREE_TYPE (*t2); 6968 6969 casts_away_constness_r (t1, t2); 6970 *t1 = build_pointer_type (*t1); 6971 *t2 = build_pointer_type (*t2); 6972 *t1 = cp_build_qualified_type (*t1, quals1); 6973 *t2 = cp_build_qualified_type (*t2, quals2); 6974} 6975 6976/* Returns nonzero if casting from TYPE1 to TYPE2 casts away 6977 constness. */ 6978 6979static bool 6980casts_away_constness (tree t1, tree t2) 6981{ 6982 if (TREE_CODE (t2) == REFERENCE_TYPE) 6983 { 6984 /* [expr.const.cast] 6985 6986 Casting from an lvalue of type T1 to an lvalue of type T2 6987 using a reference cast casts away constness if a cast from an 6988 rvalue of type "pointer to T1" to the type "pointer to T2" 6989 casts away constness. */ 6990 t1 = (TREE_CODE (t1) == REFERENCE_TYPE ? TREE_TYPE (t1) : t1); 6991 return casts_away_constness (build_pointer_type (t1), 6992 build_pointer_type (TREE_TYPE (t2))); 6993 } 6994 6995 if (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2)) 6996 /* [expr.const.cast] 6997 6998 Casting from an rvalue of type "pointer to data member of X 6999 of type T1" to the type "pointer to data member of Y of type 7000 T2" casts away constness if a cast from an rvalue of type 7001 "pointer to T1" to the type "pointer to T2" casts away 7002 constness. */ 7003 return casts_away_constness 7004 (build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t1)), 7005 build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t2))); 7006 7007 /* Casting away constness is only something that makes sense for 7008 pointer or reference types. */ 7009 if (TREE_CODE (t1) != POINTER_TYPE 7010 || TREE_CODE (t2) != POINTER_TYPE) 7011 return false; 7012 7013 /* Top-level qualifiers don't matter. */ 7014 t1 = TYPE_MAIN_VARIANT (t1); 7015 t2 = TYPE_MAIN_VARIANT (t2); 7016 casts_away_constness_r (&t1, &t2); 7017 if (!can_convert (t2, t1)) 7018 return true; 7019 7020 return false; 7021} 7022 7023/* If T is a REFERENCE_TYPE return the type to which T refers. 7024 Otherwise, return T itself. */ 7025 7026tree 7027non_reference (tree t) 7028{ 7029 if (TREE_CODE (t) == REFERENCE_TYPE) 7030 t = TREE_TYPE (t); 7031 return t; 7032} 7033 7034 7035/* Return nonzero if REF is an lvalue valid for this language; 7036 otherwise, print an error message and return zero. USE says 7037 how the lvalue is being used and so selects the error message. */ 7038 7039int 7040lvalue_or_else (tree ref, enum lvalue_use use) 7041{ 7042 int win = lvalue_p (ref); 7043 7044 if (!win) 7045 lvalue_error (use); 7046 7047 return win; 7048} 7049