typeck.c revision 261188
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); 60/* APPLE LOCAL radar 6087117 */ 61static tree convert_arguments (tree, tree, tree, int, int); 62 63/* Do `exp = require_complete_type (exp);' to make sure exp 64 does not have an incomplete type. (That includes void types.) 65 Returns the error_mark_node if the VALUE does not have 66 complete type when this function returns. */ 67 68tree 69require_complete_type (tree value) 70{ 71 tree type; 72 73 if (processing_template_decl || value == error_mark_node) 74 return value; 75 76 if (TREE_CODE (value) == OVERLOAD) 77 type = unknown_type_node; 78 else 79 type = TREE_TYPE (value); 80 81 if (type == error_mark_node) 82 return error_mark_node; 83 84 /* First, detect a valid value with a complete type. */ 85 if (COMPLETE_TYPE_P (type)) 86 return value; 87 88 if (complete_type_or_else (type, value)) 89 return value; 90 else 91 return error_mark_node; 92} 93 94/* Try to complete TYPE, if it is incomplete. For example, if TYPE is 95 a template instantiation, do the instantiation. Returns TYPE, 96 whether or not it could be completed, unless something goes 97 horribly wrong, in which case the error_mark_node is returned. */ 98 99tree 100complete_type (tree type) 101{ 102 if (type == NULL_TREE) 103 /* Rather than crash, we return something sure to cause an error 104 at some point. */ 105 return error_mark_node; 106 107 if (type == error_mark_node || COMPLETE_TYPE_P (type)) 108 ; 109 else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type)) 110 { 111 tree t = complete_type (TREE_TYPE (type)); 112 unsigned int needs_constructing, has_nontrivial_dtor; 113 if (COMPLETE_TYPE_P (t) && !dependent_type_p (type)) 114 layout_type (type); 115 needs_constructing 116 = TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (t)); 117 has_nontrivial_dtor 118 = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TYPE_MAIN_VARIANT (t)); 119 for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t)) 120 { 121 TYPE_NEEDS_CONSTRUCTING (t) = needs_constructing; 122 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (t) = has_nontrivial_dtor; 123 } 124 } 125 else if (CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INSTANTIATION (type)) 126 instantiate_class_template (TYPE_MAIN_VARIANT (type)); 127 128 return type; 129} 130 131/* Like complete_type, but issue an error if the TYPE cannot be completed. 132 VALUE is used for informative diagnostics. 133 Returns NULL_TREE if the type cannot be made complete. */ 134 135tree 136complete_type_or_else (tree type, tree value) 137{ 138 type = complete_type (type); 139 if (type == error_mark_node) 140 /* We already issued an error. */ 141 return NULL_TREE; 142 else if (!COMPLETE_TYPE_P (type)) 143 { 144 cxx_incomplete_type_diagnostic (value, type, 0); 145 return NULL_TREE; 146 } 147 else 148 return type; 149} 150 151/* Return truthvalue of whether type of EXP is instantiated. */ 152 153int 154type_unknown_p (tree exp) 155{ 156 return (TREE_CODE (exp) == TREE_LIST 157 || TREE_TYPE (exp) == unknown_type_node); 158} 159 160 161/* Return the common type of two parameter lists. 162 We assume that comptypes has already been done and returned 1; 163 if that isn't so, this may crash. 164 165 As an optimization, free the space we allocate if the parameter 166 lists are already common. */ 167 168static tree 169commonparms (tree p1, tree p2) 170{ 171 tree oldargs = p1, newargs, n; 172 int i, len; 173 int any_change = 0; 174 175 len = list_length (p1); 176 newargs = tree_last (p1); 177 178 if (newargs == void_list_node) 179 i = 1; 180 else 181 { 182 i = 0; 183 newargs = 0; 184 } 185 186 for (; i < len; i++) 187 newargs = tree_cons (NULL_TREE, NULL_TREE, newargs); 188 189 n = newargs; 190 191 for (i = 0; p1; 192 p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n), i++) 193 { 194 if (TREE_PURPOSE (p1) && !TREE_PURPOSE (p2)) 195 { 196 TREE_PURPOSE (n) = TREE_PURPOSE (p1); 197 any_change = 1; 198 } 199 else if (! TREE_PURPOSE (p1)) 200 { 201 if (TREE_PURPOSE (p2)) 202 { 203 TREE_PURPOSE (n) = TREE_PURPOSE (p2); 204 any_change = 1; 205 } 206 } 207 else 208 { 209 if (1 != simple_cst_equal (TREE_PURPOSE (p1), TREE_PURPOSE (p2))) 210 any_change = 1; 211 TREE_PURPOSE (n) = TREE_PURPOSE (p2); 212 } 213 if (TREE_VALUE (p1) != TREE_VALUE (p2)) 214 { 215 any_change = 1; 216 TREE_VALUE (n) = merge_types (TREE_VALUE (p1), TREE_VALUE (p2)); 217 } 218 else 219 TREE_VALUE (n) = TREE_VALUE (p1); 220 } 221 if (! any_change) 222 return oldargs; 223 224 return newargs; 225} 226 227/* Given a type, perhaps copied for a typedef, 228 find the "original" version of it. */ 229static tree 230original_type (tree t) 231{ 232 int quals = cp_type_quals (t); 233 while (t != error_mark_node 234 && TYPE_NAME (t) != NULL_TREE) 235 { 236 tree x = TYPE_NAME (t); 237 if (TREE_CODE (x) != TYPE_DECL) 238 break; 239 x = DECL_ORIGINAL_TYPE (x); 240 if (x == NULL_TREE) 241 break; 242 t = x; 243 } 244 return cp_build_qualified_type (t, quals); 245} 246 247/* T1 and T2 are arithmetic or enumeration types. Return the type 248 that will result from the "usual arithmetic conversions" on T1 and 249 T2 as described in [expr]. */ 250 251tree 252type_after_usual_arithmetic_conversions (tree t1, tree t2) 253{ 254 enum tree_code code1 = TREE_CODE (t1); 255 enum tree_code code2 = TREE_CODE (t2); 256 tree attributes; 257 258 /* FIXME: Attributes. */ 259 gcc_assert (ARITHMETIC_TYPE_P (t1) 260 || TREE_CODE (t1) == VECTOR_TYPE 261 || TREE_CODE (t1) == ENUMERAL_TYPE); 262 gcc_assert (ARITHMETIC_TYPE_P (t2) 263 || TREE_CODE (t2) == VECTOR_TYPE 264 || TREE_CODE (t2) == ENUMERAL_TYPE); 265 266 /* In what follows, we slightly generalize the rules given in [expr] so 267 as to deal with `long long' and `complex'. First, merge the 268 attributes. */ 269 attributes = (*targetm.merge_type_attributes) (t1, t2); 270 271 /* If one type is complex, form the common type of the non-complex 272 components, then make that complex. Use T1 or T2 if it is the 273 required type. */ 274 if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE) 275 { 276 tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1; 277 tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2; 278 tree subtype 279 = type_after_usual_arithmetic_conversions (subtype1, subtype2); 280 281 if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype) 282 return build_type_attribute_variant (t1, attributes); 283 else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype) 284 return build_type_attribute_variant (t2, attributes); 285 else 286 return build_type_attribute_variant (build_complex_type (subtype), 287 attributes); 288 } 289 290 if (code1 == VECTOR_TYPE) 291 { 292 /* When we get here we should have two vectors of the same size. 293 Just prefer the unsigned one if present. */ 294 if (TYPE_UNSIGNED (t1)) 295 return build_type_attribute_variant (t1, attributes); 296 else 297 return build_type_attribute_variant (t2, attributes); 298 } 299 300 /* If only one is real, use it as the result. */ 301 if (code1 == REAL_TYPE && code2 != REAL_TYPE) 302 return build_type_attribute_variant (t1, attributes); 303 if (code2 == REAL_TYPE && code1 != REAL_TYPE) 304 return build_type_attribute_variant (t2, attributes); 305 306 /* Perform the integral promotions. */ 307 if (code1 != REAL_TYPE) 308 { 309 t1 = type_promotes_to (t1); 310 t2 = type_promotes_to (t2); 311 } 312 313 /* Both real or both integers; use the one with greater precision. */ 314 if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2)) 315 return build_type_attribute_variant (t1, attributes); 316 else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1)) 317 return build_type_attribute_variant (t2, attributes); 318 319 /* The types are the same; no need to do anything fancy. */ 320 if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2)) 321 return build_type_attribute_variant (t1, attributes); 322 323 if (code1 != REAL_TYPE) 324 { 325 /* If one is a sizetype, use it so size_binop doesn't blow up. */ 326 if (TYPE_IS_SIZETYPE (t1) > TYPE_IS_SIZETYPE (t2)) 327 return build_type_attribute_variant (t1, attributes); 328 if (TYPE_IS_SIZETYPE (t2) > TYPE_IS_SIZETYPE (t1)) 329 return build_type_attribute_variant (t2, attributes); 330 331 /* If one is unsigned long long, then convert the other to unsigned 332 long long. */ 333 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_unsigned_type_node) 334 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_unsigned_type_node)) 335 return build_type_attribute_variant (long_long_unsigned_type_node, 336 attributes); 337 /* If one is a long long, and the other is an unsigned long, and 338 long long can represent all the values of an unsigned long, then 339 convert to a long long. Otherwise, convert to an unsigned long 340 long. Otherwise, if either operand is long long, convert the 341 other to long long. 342 343 Since we're here, we know the TYPE_PRECISION is the same; 344 therefore converting to long long cannot represent all the values 345 of an unsigned long, so we choose unsigned long long in that 346 case. */ 347 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_integer_type_node) 348 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_integer_type_node)) 349 { 350 tree t = ((TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2)) 351 ? long_long_unsigned_type_node 352 : long_long_integer_type_node); 353 return build_type_attribute_variant (t, attributes); 354 } 355 356 /* Go through the same procedure, but for longs. */ 357 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_unsigned_type_node) 358 || same_type_p (TYPE_MAIN_VARIANT (t2), long_unsigned_type_node)) 359 return build_type_attribute_variant (long_unsigned_type_node, 360 attributes); 361 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_integer_type_node) 362 || same_type_p (TYPE_MAIN_VARIANT (t2), long_integer_type_node)) 363 { 364 tree t = ((TYPE_UNSIGNED (t1) || TYPE_UNSIGNED (t2)) 365 ? long_unsigned_type_node : long_integer_type_node); 366 return build_type_attribute_variant (t, attributes); 367 } 368 /* Otherwise prefer the unsigned one. */ 369 if (TYPE_UNSIGNED (t1)) 370 return build_type_attribute_variant (t1, attributes); 371 else 372 return build_type_attribute_variant (t2, attributes); 373 } 374 else 375 { 376 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_double_type_node) 377 || same_type_p (TYPE_MAIN_VARIANT (t2), long_double_type_node)) 378 return build_type_attribute_variant (long_double_type_node, 379 attributes); 380 if (same_type_p (TYPE_MAIN_VARIANT (t1), double_type_node) 381 || same_type_p (TYPE_MAIN_VARIANT (t2), double_type_node)) 382 return build_type_attribute_variant (double_type_node, 383 attributes); 384 if (same_type_p (TYPE_MAIN_VARIANT (t1), float_type_node) 385 || same_type_p (TYPE_MAIN_VARIANT (t2), float_type_node)) 386 return build_type_attribute_variant (float_type_node, 387 attributes); 388 389 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of 390 the standard C++ floating-point types. Logic earlier in this 391 function has already eliminated the possibility that 392 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no 393 compelling reason to choose one or the other. */ 394 return build_type_attribute_variant (t1, attributes); 395 } 396} 397 398/* Subroutine of composite_pointer_type to implement the recursive 399 case. See that function for documentation fo the parameters. */ 400 401static tree 402composite_pointer_type_r (tree t1, tree t2, const char* location) 403{ 404 tree pointee1; 405 tree pointee2; 406 tree result_type; 407 tree attributes; 408 409 /* Determine the types pointed to by T1 and T2. */ 410 /* APPLE LOCAL blocks 6040305 */ 411 if (TREE_CODE (t1) == POINTER_TYPE || TREE_CODE (t1) == BLOCK_POINTER_TYPE) 412 { 413 pointee1 = TREE_TYPE (t1); 414 pointee2 = TREE_TYPE (t2); 415 } 416 else 417 { 418 pointee1 = TYPE_PTRMEM_POINTED_TO_TYPE (t1); 419 pointee2 = TYPE_PTRMEM_POINTED_TO_TYPE (t2); 420 } 421 422 /* [expr.rel] 423 424 Otherwise, the composite pointer type is a pointer type 425 similar (_conv.qual_) to the type of one of the operands, 426 with a cv-qualification signature (_conv.qual_) that is the 427 union of the cv-qualification signatures of the operand 428 types. */ 429 if (same_type_ignoring_top_level_qualifiers_p (pointee1, pointee2)) 430 result_type = pointee1; 431 else if ((TREE_CODE (pointee1) == POINTER_TYPE 432 && TREE_CODE (pointee2) == POINTER_TYPE) 433 || (TYPE_PTR_TO_MEMBER_P (pointee1) 434 && TYPE_PTR_TO_MEMBER_P (pointee2))) 435 result_type = composite_pointer_type_r (pointee1, pointee2, location); 436 else 437 { 438 pedwarn ("%s between distinct pointer types %qT and %qT " 439 "lacks a cast", 440 location, t1, t2); 441 result_type = void_type_node; 442 } 443 result_type = cp_build_qualified_type (result_type, 444 (cp_type_quals (pointee1) 445 | cp_type_quals (pointee2))); 446 /* If the original types were pointers to members, so is the 447 result. */ 448 if (TYPE_PTR_TO_MEMBER_P (t1)) 449 { 450 if (!same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1), 451 TYPE_PTRMEM_CLASS_TYPE (t2))) 452 pedwarn ("%s between distinct pointer types %qT and %qT " 453 "lacks a cast", 454 location, t1, t2); 455 result_type = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1), 456 result_type); 457 } 458 /* APPLE LOCAL begin blocks 6065211 */ 459 else if (TREE_CODE (t1) == BLOCK_POINTER_TYPE 460 && result_type != void_type_node) 461 result_type = build_block_pointer_type (result_type); 462 else 463 result_type = build_pointer_type (result_type); 464 /* APPLE LOCAL end blocks 6065211 */ 465 466 /* Merge the attributes. */ 467 attributes = (*targetm.merge_type_attributes) (t1, t2); 468 return build_type_attribute_variant (result_type, attributes); 469} 470 471/* Return the composite pointer type (see [expr.rel]) for T1 and T2. 472 ARG1 and ARG2 are the values with those types. The LOCATION is a 473 string describing the current location, in case an error occurs. 474 475 This routine also implements the computation of a common type for 476 pointers-to-members as per [expr.eq]. */ 477 478tree 479composite_pointer_type (tree t1, tree t2, tree arg1, tree arg2, 480 const char* location) 481{ 482 tree class1; 483 tree class2; 484 485 /* [expr.rel] 486 487 If one operand is a null pointer constant, the composite pointer 488 type is the type of the other operand. */ 489 if (null_ptr_cst_p (arg1)) 490 return t2; 491 if (null_ptr_cst_p (arg2)) 492 return t1; 493 494 /* We have: 495 496 [expr.rel] 497 498 If one of the operands has type "pointer to cv1 void*", then 499 the other has type "pointer to cv2T", and the composite pointer 500 type is "pointer to cv12 void", where cv12 is the union of cv1 501 and cv2. 502 503 If either type is a pointer to void, make sure it is T1. */ 504 if (TREE_CODE (t2) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t2))) 505 { 506 tree t; 507 t = t1; 508 t1 = t2; 509 t2 = t; 510 } 511 512 /* Now, if T1 is a pointer to void, merge the qualifiers. */ 513 if (TREE_CODE (t1) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t1))) 514 { 515 tree attributes; 516 tree result_type; 517 518 if (pedantic && TYPE_PTRFN_P (t2)) 519 pedwarn ("ISO C++ forbids %s between pointer of type %<void *%> " 520 "and pointer-to-function", location); 521 result_type 522 = cp_build_qualified_type (void_type_node, 523 (cp_type_quals (TREE_TYPE (t1)) 524 | cp_type_quals (TREE_TYPE (t2)))); 525 result_type = build_pointer_type (result_type); 526 /* Merge the attributes. */ 527 attributes = (*targetm.merge_type_attributes) (t1, t2); 528 return build_type_attribute_variant (result_type, attributes); 529 } 530 531 if (c_dialect_objc () && TREE_CODE (t1) == POINTER_TYPE 532 && TREE_CODE (t2) == POINTER_TYPE) 533 { 534 /* APPLE LOCAL radar 4229905 - radar 6231433 */ 535 if (objc_have_common_type (t1, t2, -3, NULL_TREE, location)) 536 /* APPLE LOCAL 4154928 */ 537 return objc_common_type (t1, t2); 538 } 539 540 /* [expr.eq] permits the application of a pointer conversion to 541 bring the pointers to a common type. */ 542 if (TREE_CODE (t1) == POINTER_TYPE && TREE_CODE (t2) == POINTER_TYPE 543 && CLASS_TYPE_P (TREE_TYPE (t1)) 544 && CLASS_TYPE_P (TREE_TYPE (t2)) 545 && !same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (t1), 546 TREE_TYPE (t2))) 547 { 548 class1 = TREE_TYPE (t1); 549 class2 = TREE_TYPE (t2); 550 551 if (DERIVED_FROM_P (class1, class2)) 552 t2 = (build_pointer_type 553 (cp_build_qualified_type (class1, TYPE_QUALS (class2)))); 554 else if (DERIVED_FROM_P (class2, class1)) 555 t1 = (build_pointer_type 556 (cp_build_qualified_type (class2, TYPE_QUALS (class1)))); 557 else 558 { 559 error ("%s between distinct pointer types %qT and %qT " 560 "lacks a cast", location, t1, t2); 561 return error_mark_node; 562 } 563 } 564 /* [expr.eq] permits the application of a pointer-to-member 565 conversion to change the class type of one of the types. */ 566 else if (TYPE_PTR_TO_MEMBER_P (t1) 567 && !same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1), 568 TYPE_PTRMEM_CLASS_TYPE (t2))) 569 { 570 class1 = TYPE_PTRMEM_CLASS_TYPE (t1); 571 class2 = TYPE_PTRMEM_CLASS_TYPE (t2); 572 573 if (DERIVED_FROM_P (class1, class2)) 574 t1 = build_ptrmem_type (class2, TYPE_PTRMEM_POINTED_TO_TYPE (t1)); 575 else if (DERIVED_FROM_P (class2, class1)) 576 t2 = build_ptrmem_type (class1, TYPE_PTRMEM_POINTED_TO_TYPE (t2)); 577 else 578 { 579 error ("%s between distinct pointer-to-member types %qT and %qT " 580 "lacks a cast", location, t1, t2); 581 return error_mark_node; 582 } 583 } 584 /* APPLE LOCAL begin blocks 6065211 */ 585 else if (TREE_CODE (t1) != TREE_CODE (t2)) 586 { 587 error ("%s between distinct pointer types %qT and %qT " 588 "lacks a cast", location, t1, t2); 589 return error_mark_node; 590 } 591 /* APPLE LOCAL end blocks 6065211 */ 592 593 return composite_pointer_type_r (t1, t2, location); 594} 595 596/* Return the merged type of two types. 597 We assume that comptypes has already been done and returned 1; 598 if that isn't so, this may crash. 599 600 This just combines attributes and default arguments; any other 601 differences would cause the two types to compare unalike. */ 602 603tree 604merge_types (tree t1, tree t2) 605{ 606 enum tree_code code1; 607 enum tree_code code2; 608 tree attributes; 609 610 /* Save time if the two types are the same. */ 611 if (t1 == t2) 612 return t1; 613 if (original_type (t1) == original_type (t2)) 614 return t1; 615 616 /* If one type is nonsense, use the other. */ 617 if (t1 == error_mark_node) 618 return t2; 619 if (t2 == error_mark_node) 620 return t1; 621 622 /* Merge the attributes. */ 623 attributes = (*targetm.merge_type_attributes) (t1, t2); 624 625 if (TYPE_PTRMEMFUNC_P (t1)) 626 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1); 627 if (TYPE_PTRMEMFUNC_P (t2)) 628 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2); 629 630 code1 = TREE_CODE (t1); 631 code2 = TREE_CODE (t2); 632 633 switch (code1) 634 { 635 case POINTER_TYPE: 636 case REFERENCE_TYPE: 637 /* For two pointers, do this recursively on the target type. */ 638 { 639 tree target = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 640 int quals = cp_type_quals (t1); 641 642 if (code1 == POINTER_TYPE) 643 t1 = build_pointer_type (target); 644 else 645 t1 = build_reference_type (target); 646 t1 = build_type_attribute_variant (t1, attributes); 647 t1 = cp_build_qualified_type (t1, quals); 648 649 if (TREE_CODE (target) == METHOD_TYPE) 650 t1 = build_ptrmemfunc_type (t1); 651 652 return t1; 653 } 654 655 case OFFSET_TYPE: 656 { 657 int quals; 658 tree pointee; 659 quals = cp_type_quals (t1); 660 pointee = merge_types (TYPE_PTRMEM_POINTED_TO_TYPE (t1), 661 TYPE_PTRMEM_POINTED_TO_TYPE (t2)); 662 t1 = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1), 663 pointee); 664 t1 = cp_build_qualified_type (t1, quals); 665 break; 666 } 667 668 case ARRAY_TYPE: 669 { 670 tree elt = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 671 /* Save space: see if the result is identical to one of the args. */ 672 if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)) 673 return build_type_attribute_variant (t1, attributes); 674 if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)) 675 return build_type_attribute_variant (t2, attributes); 676 /* Merge the element types, and have a size if either arg has one. */ 677 t1 = build_cplus_array_type 678 (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2)); 679 break; 680 } 681 682 case FUNCTION_TYPE: 683 /* Function types: prefer the one that specified arg types. 684 If both do, merge the arg types. Also merge the return types. */ 685 { 686 tree valtype = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 687 tree p1 = TYPE_ARG_TYPES (t1); 688 tree p2 = TYPE_ARG_TYPES (t2); 689 tree rval, raises; 690 691 /* Save space: see if the result is identical to one of the args. */ 692 if (valtype == TREE_TYPE (t1) && ! p2) 693 return cp_build_type_attribute_variant (t1, attributes); 694 if (valtype == TREE_TYPE (t2) && ! p1) 695 return cp_build_type_attribute_variant (t2, attributes); 696 697 /* Simple way if one arg fails to specify argument types. */ 698 if (p1 == NULL_TREE || TREE_VALUE (p1) == void_type_node) 699 { 700 rval = build_function_type (valtype, p2); 701 if ((raises = TYPE_RAISES_EXCEPTIONS (t2))) 702 rval = build_exception_variant (rval, raises); 703 return cp_build_type_attribute_variant (rval, attributes); 704 } 705 raises = TYPE_RAISES_EXCEPTIONS (t1); 706 if (p2 == NULL_TREE || TREE_VALUE (p2) == void_type_node) 707 { 708 rval = build_function_type (valtype, p1); 709 if (raises) 710 rval = build_exception_variant (rval, raises); 711 return cp_build_type_attribute_variant (rval, attributes); 712 } 713 714 rval = build_function_type (valtype, commonparms (p1, p2)); 715 t1 = build_exception_variant (rval, raises); 716 break; 717 } 718 719 case METHOD_TYPE: 720 { 721 /* Get this value the long way, since TYPE_METHOD_BASETYPE 722 is just the main variant of this. */ 723 tree basetype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t2))); 724 tree raises = TYPE_RAISES_EXCEPTIONS (t1); 725 tree t3; 726 727 /* If this was a member function type, get back to the 728 original type of type member function (i.e., without 729 the class instance variable up front. */ 730 t1 = build_function_type (TREE_TYPE (t1), 731 TREE_CHAIN (TYPE_ARG_TYPES (t1))); 732 t2 = build_function_type (TREE_TYPE (t2), 733 TREE_CHAIN (TYPE_ARG_TYPES (t2))); 734 t3 = merge_types (t1, t2); 735 t3 = build_method_type_directly (basetype, TREE_TYPE (t3), 736 TYPE_ARG_TYPES (t3)); 737 t1 = build_exception_variant (t3, raises); 738 break; 739 } 740 741 case TYPENAME_TYPE: 742 /* There is no need to merge attributes into a TYPENAME_TYPE. 743 When the type is instantiated it will have whatever 744 attributes result from the instantiation. */ 745 return t1; 746 747 default:; 748 } 749 750 if (attribute_list_equal (TYPE_ATTRIBUTES (t1), attributes)) 751 return t1; 752 else if (attribute_list_equal (TYPE_ATTRIBUTES (t2), attributes)) 753 return t2; 754 else 755 return cp_build_type_attribute_variant (t1, attributes); 756} 757 758/* Return the common type of two types. 759 We assume that comptypes has already been done and returned 1; 760 if that isn't so, this may crash. 761 762 This is the type for the result of most arithmetic operations 763 if the operands have the given two types. */ 764 765tree 766common_type (tree t1, tree t2) 767{ 768 enum tree_code code1; 769 enum tree_code code2; 770 771 /* If one type is nonsense, bail. */ 772 if (t1 == error_mark_node || t2 == error_mark_node) 773 return error_mark_node; 774 775 code1 = TREE_CODE (t1); 776 code2 = TREE_CODE (t2); 777 778 if ((ARITHMETIC_TYPE_P (t1) || code1 == ENUMERAL_TYPE 779 || code1 == VECTOR_TYPE) 780 && (ARITHMETIC_TYPE_P (t2) || code2 == ENUMERAL_TYPE 781 || code2 == VECTOR_TYPE)) 782 return type_after_usual_arithmetic_conversions (t1, t2); 783 784 else if ((TYPE_PTR_P (t1) && TYPE_PTR_P (t2)) 785 || (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2)) 786 || (TYPE_PTRMEMFUNC_P (t1) && TYPE_PTRMEMFUNC_P (t2))) 787 return composite_pointer_type (t1, t2, error_mark_node, error_mark_node, 788 "conversion"); 789 else 790 gcc_unreachable (); 791} 792 793/* Compare two exception specifier types for exactness or subsetness, if 794 allowed. Returns false for mismatch, true for match (same, or 795 derived and !exact). 796 797 [except.spec] "If a class X ... objects of class X or any class publicly 798 and unambiguously derived from X. Similarly, if a pointer type Y * ... 799 exceptions of type Y * or that are pointers to any type publicly and 800 unambiguously derived from Y. Otherwise a function only allows exceptions 801 that have the same type ..." 802 This does not mention cv qualifiers and is different to what throw 803 [except.throw] and catch [except.catch] will do. They will ignore the 804 top level cv qualifiers, and allow qualifiers in the pointer to class 805 example. 806 807 We implement the letter of the standard. */ 808 809static bool 810comp_except_types (tree a, tree b, bool exact) 811{ 812 if (same_type_p (a, b)) 813 return true; 814 else if (!exact) 815 { 816 if (cp_type_quals (a) || cp_type_quals (b)) 817 return false; 818 819 if (TREE_CODE (a) == POINTER_TYPE 820 && TREE_CODE (b) == POINTER_TYPE) 821 { 822 a = TREE_TYPE (a); 823 b = TREE_TYPE (b); 824 if (cp_type_quals (a) || cp_type_quals (b)) 825 return false; 826 } 827 828 if (TREE_CODE (a) != RECORD_TYPE 829 || TREE_CODE (b) != RECORD_TYPE) 830 return false; 831 832 if (PUBLICLY_UNIQUELY_DERIVED_P (a, b)) 833 return true; 834 } 835 return false; 836} 837 838/* Return true if TYPE1 and TYPE2 are equivalent exception specifiers. 839 If EXACT is false, T2 can be stricter than T1 (according to 15.4/7), 840 otherwise it must be exact. Exception lists are unordered, but 841 we've already filtered out duplicates. Most lists will be in order, 842 we should try to make use of that. */ 843 844bool 845comp_except_specs (tree t1, tree t2, bool exact) 846{ 847 tree probe; 848 tree base; 849 int length = 0; 850 851 if (t1 == t2) 852 return true; 853 854 if (t1 == NULL_TREE) /* T1 is ... */ 855 return t2 == NULL_TREE || !exact; 856 if (!TREE_VALUE (t1)) /* t1 is EMPTY */ 857 return t2 != NULL_TREE && !TREE_VALUE (t2); 858 if (t2 == NULL_TREE) /* T2 is ... */ 859 return false; 860 if (TREE_VALUE (t1) && !TREE_VALUE (t2)) /* T2 is EMPTY, T1 is not */ 861 return !exact; 862 863 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1. 864 Count how many we find, to determine exactness. For exact matching and 865 ordered T1, T2, this is an O(n) operation, otherwise its worst case is 866 O(nm). */ 867 for (base = t1; t2 != NULL_TREE; t2 = TREE_CHAIN (t2)) 868 { 869 for (probe = base; probe != NULL_TREE; probe = TREE_CHAIN (probe)) 870 { 871 tree a = TREE_VALUE (probe); 872 tree b = TREE_VALUE (t2); 873 874 if (comp_except_types (a, b, exact)) 875 { 876 if (probe == base && exact) 877 base = TREE_CHAIN (probe); 878 length++; 879 break; 880 } 881 } 882 if (probe == NULL_TREE) 883 return false; 884 } 885 return !exact || base == NULL_TREE || length == list_length (t1); 886} 887 888/* Compare the array types T1 and T2. ALLOW_REDECLARATION is true if 889 [] can match [size]. */ 890 891static bool 892comp_array_types (tree t1, tree t2, bool allow_redeclaration) 893{ 894 tree d1; 895 tree d2; 896 tree max1, max2; 897 898 if (t1 == t2) 899 return true; 900 901 /* The type of the array elements must be the same. */ 902 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 903 return false; 904 905 d1 = TYPE_DOMAIN (t1); 906 d2 = TYPE_DOMAIN (t2); 907 908 if (d1 == d2) 909 return true; 910 911 /* If one of the arrays is dimensionless, and the other has a 912 dimension, they are of different types. However, it is valid to 913 write: 914 915 extern int a[]; 916 int a[3]; 917 918 by [basic.link]: 919 920 declarations for an array object can specify 921 array types that differ by the presence or absence of a major 922 array bound (_dcl.array_). */ 923 if (!d1 || !d2) 924 return allow_redeclaration; 925 926 /* Check that the dimensions are the same. */ 927 928 if (!cp_tree_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))) 929 return false; 930 max1 = TYPE_MAX_VALUE (d1); 931 max2 = TYPE_MAX_VALUE (d2); 932 if (processing_template_decl && !abi_version_at_least (2) 933 && !value_dependent_expression_p (max1) 934 && !value_dependent_expression_p (max2)) 935 { 936 /* With abi-1 we do not fold non-dependent array bounds, (and 937 consequently mangle them incorrectly). We must therefore 938 fold them here, to verify the domains have the same 939 value. */ 940 max1 = fold (max1); 941 max2 = fold (max2); 942 } 943 944 if (!cp_tree_equal (max1, max2)) 945 return false; 946 947 return true; 948} 949 950/* Return true if T1 and T2 are related as allowed by STRICT. STRICT 951 is a bitwise-or of the COMPARE_* flags. */ 952 953bool 954comptypes (tree t1, tree t2, int strict) 955{ 956 if (t1 == t2) 957 return true; 958 959 /* Suppress errors caused by previously reported errors. */ 960 if (t1 == error_mark_node || t2 == error_mark_node) 961 return false; 962 963 gcc_assert (TYPE_P (t1) && TYPE_P (t2)); 964 965 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the 966 current instantiation. */ 967 if (TREE_CODE (t1) == TYPENAME_TYPE) 968 { 969 tree resolved = resolve_typename_type (t1, /*only_current_p=*/true); 970 971 if (resolved != error_mark_node) 972 t1 = resolved; 973 } 974 975 if (TREE_CODE (t2) == TYPENAME_TYPE) 976 { 977 tree resolved = resolve_typename_type (t2, /*only_current_p=*/true); 978 979 if (resolved != error_mark_node) 980 t2 = resolved; 981 } 982 983 /* If either type is the internal version of sizetype, use the 984 language version. */ 985 if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1) 986 && TYPE_ORIG_SIZE_TYPE (t1)) 987 t1 = TYPE_ORIG_SIZE_TYPE (t1); 988 989 if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2) 990 && TYPE_ORIG_SIZE_TYPE (t2)) 991 t2 = TYPE_ORIG_SIZE_TYPE (t2); 992 993 if (TYPE_PTRMEMFUNC_P (t1)) 994 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1); 995 if (TYPE_PTRMEMFUNC_P (t2)) 996 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2); 997 998 /* Different classes of types can't be compatible. */ 999 if (TREE_CODE (t1) != TREE_CODE (t2)) 1000 return false; 1001 1002 /* Qualifiers must match. For array types, we will check when we 1003 recur on the array element types. */ 1004 if (TREE_CODE (t1) != ARRAY_TYPE 1005 && TYPE_QUALS (t1) != TYPE_QUALS (t2)) 1006 return false; 1007 if (TYPE_FOR_JAVA (t1) != TYPE_FOR_JAVA (t2)) 1008 return false; 1009 1010 /* Allow for two different type nodes which have essentially the same 1011 definition. Note that we already checked for equality of the type 1012 qualifiers (just above). */ 1013 1014 if (TREE_CODE (t1) != ARRAY_TYPE 1015 && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2)) 1016 return true; 1017 1018 /* Compare the types. Break out if they could be the same. */ 1019 switch (TREE_CODE (t1)) 1020 { 1021 case TEMPLATE_TEMPLATE_PARM: 1022 case BOUND_TEMPLATE_TEMPLATE_PARM: 1023 if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2) 1024 || TEMPLATE_TYPE_LEVEL (t1) != TEMPLATE_TYPE_LEVEL (t2)) 1025 return false; 1026 if (!comp_template_parms 1027 (DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t1)), 1028 DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t2)))) 1029 return false; 1030 if (TREE_CODE (t1) == TEMPLATE_TEMPLATE_PARM) 1031 break; 1032 /* Don't check inheritance. */ 1033 strict = COMPARE_STRICT; 1034 /* Fall through. */ 1035 1036 case RECORD_TYPE: 1037 case UNION_TYPE: 1038 if (TYPE_TEMPLATE_INFO (t1) && TYPE_TEMPLATE_INFO (t2) 1039 && (TYPE_TI_TEMPLATE (t1) == TYPE_TI_TEMPLATE (t2) 1040 || TREE_CODE (t1) == BOUND_TEMPLATE_TEMPLATE_PARM) 1041 && comp_template_args (TYPE_TI_ARGS (t1), TYPE_TI_ARGS (t2))) 1042 break; 1043 1044 if ((strict & COMPARE_BASE) && DERIVED_FROM_P (t1, t2)) 1045 break; 1046 else if ((strict & COMPARE_DERIVED) && DERIVED_FROM_P (t2, t1)) 1047 break; 1048 1049 return false; 1050 1051 case OFFSET_TYPE: 1052 if (!comptypes (TYPE_OFFSET_BASETYPE (t1), TYPE_OFFSET_BASETYPE (t2), 1053 strict & ~COMPARE_REDECLARATION)) 1054 return false; 1055 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1056 return false; 1057 break; 1058 1059 /* APPLE LOCAL begin blocks 6040305 */ 1060 case BLOCK_POINTER_TYPE: 1061 if (TREE_CODE (t2) == BLOCK_POINTER_TYPE) 1062 { 1063 tree pt1 = TREE_TYPE (t1); 1064 tree pt2 = TREE_TYPE (t2); 1065 if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (pt1), 1066 TREE_TYPE (pt2))) 1067 return false; 1068 if (!compparms (TYPE_ARG_TYPES (pt1), TYPE_ARG_TYPES (pt2))) 1069 return false; 1070 break; 1071 } 1072 /* APPLE LOCAL end blocks 6040305 */ 1073 1074 case POINTER_TYPE: 1075 case REFERENCE_TYPE: 1076 if (TYPE_MODE (t1) != TYPE_MODE (t2) 1077 || TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2) 1078 || !same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1079 return false; 1080 break; 1081 1082 case METHOD_TYPE: 1083 case FUNCTION_TYPE: 1084 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1085 return false; 1086 if (!compparms (TYPE_ARG_TYPES (t1), TYPE_ARG_TYPES (t2))) 1087 return false; 1088 break; 1089 1090 case ARRAY_TYPE: 1091 /* Target types must match incl. qualifiers. */ 1092 if (!comp_array_types (t1, t2, !!(strict & COMPARE_REDECLARATION))) 1093 return false; 1094 break; 1095 1096 case TEMPLATE_TYPE_PARM: 1097 if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2) 1098 || TEMPLATE_TYPE_LEVEL (t1) != TEMPLATE_TYPE_LEVEL (t2)) 1099 return false; 1100 break; 1101 1102 case TYPENAME_TYPE: 1103 if (!cp_tree_equal (TYPENAME_TYPE_FULLNAME (t1), 1104 TYPENAME_TYPE_FULLNAME (t2))) 1105 return false; 1106 if (!same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2))) 1107 return false; 1108 break; 1109 1110 case UNBOUND_CLASS_TEMPLATE: 1111 if (!cp_tree_equal (TYPE_IDENTIFIER (t1), TYPE_IDENTIFIER (t2))) 1112 return false; 1113 if (!same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2))) 1114 return false; 1115 break; 1116 1117 case COMPLEX_TYPE: 1118 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1119 return false; 1120 break; 1121 1122 case VECTOR_TYPE: 1123 if (TYPE_VECTOR_SUBPARTS (t1) != TYPE_VECTOR_SUBPARTS (t2) 1124 || !same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1125 return false; 1126 break; 1127 1128 default: 1129 return false; 1130 } 1131 1132 /* If we get here, we know that from a target independent POV the 1133 types are the same. Make sure the target attributes are also 1134 the same. */ 1135 return targetm.comp_type_attributes (t1, t2); 1136} 1137 1138/* Returns 1 if TYPE1 is at least as qualified as TYPE2. */ 1139 1140bool 1141at_least_as_qualified_p (tree type1, tree type2) 1142{ 1143 int q1 = cp_type_quals (type1); 1144 int q2 = cp_type_quals (type2); 1145 1146 /* All qualifiers for TYPE2 must also appear in TYPE1. */ 1147 return (q1 & q2) == q2; 1148} 1149 1150/* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is 1151 more cv-qualified that TYPE1, and 0 otherwise. */ 1152 1153int 1154comp_cv_qualification (tree type1, tree type2) 1155{ 1156 int q1 = cp_type_quals (type1); 1157 int q2 = cp_type_quals (type2); 1158 1159 if (q1 == q2) 1160 return 0; 1161 1162 if ((q1 & q2) == q2) 1163 return 1; 1164 else if ((q1 & q2) == q1) 1165 return -1; 1166 1167 return 0; 1168} 1169 1170/* Returns 1 if the cv-qualification signature of TYPE1 is a proper 1171 subset of the cv-qualification signature of TYPE2, and the types 1172 are similar. Returns -1 if the other way 'round, and 0 otherwise. */ 1173 1174int 1175comp_cv_qual_signature (tree type1, tree type2) 1176{ 1177 if (comp_ptr_ttypes_real (type2, type1, -1)) 1178 return 1; 1179 else if (comp_ptr_ttypes_real (type1, type2, -1)) 1180 return -1; 1181 else 1182 return 0; 1183} 1184 1185/* If two types share a common base type, return that basetype. 1186 If there is not a unique most-derived base type, this function 1187 returns ERROR_MARK_NODE. */ 1188 1189static tree 1190common_base_type (tree tt1, tree tt2) 1191{ 1192 tree best = NULL_TREE; 1193 int i; 1194 1195 /* If one is a baseclass of another, that's good enough. */ 1196 if (UNIQUELY_DERIVED_FROM_P (tt1, tt2)) 1197 return tt1; 1198 if (UNIQUELY_DERIVED_FROM_P (tt2, tt1)) 1199 return tt2; 1200 1201 /* Otherwise, try to find a unique baseclass of TT1 1202 that is shared by TT2, and follow that down. */ 1203 for (i = BINFO_N_BASE_BINFOS (TYPE_BINFO (tt1))-1; i >= 0; i--) 1204 { 1205 tree basetype = BINFO_TYPE (BINFO_BASE_BINFO (TYPE_BINFO (tt1), i)); 1206 tree trial = common_base_type (basetype, tt2); 1207 1208 if (trial) 1209 { 1210 if (trial == error_mark_node) 1211 return trial; 1212 if (best == NULL_TREE) 1213 best = trial; 1214 else if (best != trial) 1215 return error_mark_node; 1216 } 1217 } 1218 1219 /* Same for TT2. */ 1220 for (i = BINFO_N_BASE_BINFOS (TYPE_BINFO (tt2))-1; i >= 0; i--) 1221 { 1222 tree basetype = BINFO_TYPE (BINFO_BASE_BINFO (TYPE_BINFO (tt2), i)); 1223 tree trial = common_base_type (tt1, basetype); 1224 1225 if (trial) 1226 { 1227 if (trial == error_mark_node) 1228 return trial; 1229 if (best == NULL_TREE) 1230 best = trial; 1231 else if (best != trial) 1232 return error_mark_node; 1233 } 1234 } 1235 return best; 1236} 1237 1238/* Subroutines of `comptypes'. */ 1239 1240/* Return true if two parameter type lists PARMS1 and PARMS2 are 1241 equivalent in the sense that functions with those parameter types 1242 can have equivalent types. The two lists must be equivalent, 1243 element by element. */ 1244 1245bool 1246compparms (tree parms1, tree parms2) 1247{ 1248 tree t1, t2; 1249 1250 /* An unspecified parmlist matches any specified parmlist 1251 whose argument types don't need default promotions. */ 1252 1253 for (t1 = parms1, t2 = parms2; 1254 t1 || t2; 1255 t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2)) 1256 { 1257 /* If one parmlist is shorter than the other, 1258 they fail to match. */ 1259 if (!t1 || !t2) 1260 return false; 1261 if (!same_type_p (TREE_VALUE (t1), TREE_VALUE (t2))) 1262 return false; 1263 } 1264 return true; 1265} 1266 1267 1268/* Process a sizeof or alignof expression where the operand is a 1269 type. */ 1270 1271tree 1272cxx_sizeof_or_alignof_type (tree type, enum tree_code op, bool complain) 1273{ 1274 tree value; 1275 bool dependent_p; 1276 1277 gcc_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR); 1278 if (type == error_mark_node) 1279 return error_mark_node; 1280 1281 type = non_reference (type); 1282 if (TREE_CODE (type) == METHOD_TYPE) 1283 { 1284 if (complain && (pedantic || warn_pointer_arith)) 1285 pedwarn ("invalid application of %qs to a member function", 1286 operator_name_info[(int) op].name); 1287 value = size_one_node; 1288 } 1289 1290 dependent_p = dependent_type_p (type); 1291 if (!dependent_p) 1292 complete_type (type); 1293 if (dependent_p 1294 /* VLA types will have a non-constant size. In the body of an 1295 uninstantiated template, we don't need to try to compute the 1296 value, because the sizeof expression is not an integral 1297 constant expression in that case. And, if we do try to 1298 compute the value, we'll likely end up with SAVE_EXPRs, which 1299 the template substitution machinery does not expect to see. */ 1300 || (processing_template_decl 1301 && COMPLETE_TYPE_P (type) 1302 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)) 1303 { 1304 value = build_min (op, size_type_node, type); 1305 TREE_READONLY (value) = 1; 1306 return value; 1307 } 1308 1309 return c_sizeof_or_alignof_type (complete_type (type), 1310 op == SIZEOF_EXPR, 1311 complain); 1312} 1313 1314/* Process a sizeof expression where the operand is an expression. */ 1315 1316static tree 1317cxx_sizeof_expr (tree e) 1318{ 1319 if (e == error_mark_node) 1320 return error_mark_node; 1321 1322 if (processing_template_decl) 1323 { 1324 e = build_min (SIZEOF_EXPR, size_type_node, e); 1325 TREE_SIDE_EFFECTS (e) = 0; 1326 TREE_READONLY (e) = 1; 1327 1328 return e; 1329 } 1330 1331 if (TREE_CODE (e) == COMPONENT_REF 1332 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL 1333 && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1))) 1334 { 1335 error ("invalid application of %<sizeof%> to a bit-field"); 1336 e = char_type_node; 1337 } 1338 else if (is_overloaded_fn (e)) 1339 { 1340 pedwarn ("ISO C++ forbids applying %<sizeof%> to an expression of " 1341 "function type"); 1342 e = char_type_node; 1343 } 1344 else if (type_unknown_p (e)) 1345 { 1346 cxx_incomplete_type_error (e, TREE_TYPE (e)); 1347 e = char_type_node; 1348 } 1349 else 1350 e = TREE_TYPE (e); 1351 1352 return cxx_sizeof_or_alignof_type (e, SIZEOF_EXPR, true); 1353} 1354 1355/* Implement the __alignof keyword: Return the minimum required 1356 alignment of E, measured in bytes. For VAR_DECL's and 1357 FIELD_DECL's return DECL_ALIGN (which can be set from an 1358 "aligned" __attribute__ specification). */ 1359 1360static tree 1361cxx_alignof_expr (tree e) 1362{ 1363 tree t; 1364 1365 if (e == error_mark_node) 1366 return error_mark_node; 1367 1368 if (processing_template_decl) 1369 { 1370 e = build_min (ALIGNOF_EXPR, size_type_node, e); 1371 TREE_SIDE_EFFECTS (e) = 0; 1372 TREE_READONLY (e) = 1; 1373 1374 return e; 1375 } 1376 1377 if (TREE_CODE (e) == VAR_DECL) 1378 t = size_int (DECL_ALIGN_UNIT (e)); 1379 else if (TREE_CODE (e) == COMPONENT_REF 1380 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL 1381 && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1))) 1382 { 1383 error ("invalid application of %<__alignof%> to a bit-field"); 1384 t = size_one_node; 1385 } 1386 else if (TREE_CODE (e) == COMPONENT_REF 1387 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL) 1388 t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (e, 1))); 1389 else if (is_overloaded_fn (e)) 1390 { 1391 pedwarn ("ISO C++ forbids applying %<__alignof%> to an expression of " 1392 "function type"); 1393 if (TREE_CODE (e) == FUNCTION_DECL) 1394 t = size_int (DECL_ALIGN_UNIT (e)); 1395 else 1396 t = size_one_node; 1397 } 1398 else if (type_unknown_p (e)) 1399 { 1400 cxx_incomplete_type_error (e, TREE_TYPE (e)); 1401 t = size_one_node; 1402 } 1403 else 1404 return cxx_sizeof_or_alignof_type (TREE_TYPE (e), ALIGNOF_EXPR, true); 1405 1406 return fold_convert (size_type_node, t); 1407} 1408 1409/* Process a sizeof or alignof expression E with code OP where the operand 1410 is an expression. */ 1411 1412tree 1413cxx_sizeof_or_alignof_expr (tree e, enum tree_code op) 1414{ 1415 if (op == SIZEOF_EXPR) 1416 return cxx_sizeof_expr (e); 1417 else 1418 return cxx_alignof_expr (e); 1419} 1420 1421/* EXPR is being used in a context that is not a function call. 1422 Enforce: 1423 1424 [expr.ref] 1425 1426 The expression can be used only as the left-hand operand of a 1427 member function call. 1428 1429 [expr.mptr.operator] 1430 1431 If the result of .* or ->* is a function, then that result can be 1432 used only as the operand for the function call operator (). 1433 1434 by issuing an error message if appropriate. Returns true iff EXPR 1435 violates these rules. */ 1436 1437bool 1438invalid_nonstatic_memfn_p (tree expr) 1439{ 1440 if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) 1441 { 1442 error ("invalid use of non-static member function"); 1443 return true; 1444 } 1445 return false; 1446} 1447 1448/* If EXP is a reference to a bitfield, and the type of EXP does not 1449 match the declared type of the bitfield, return the declared type 1450 of the bitfield. Otherwise, return NULL_TREE. */ 1451 1452tree 1453is_bitfield_expr_with_lowered_type (tree exp) 1454{ 1455 switch (TREE_CODE (exp)) 1456 { 1457 case COND_EXPR: 1458 if (!is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 1))) 1459 return NULL_TREE; 1460 return is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 2)); 1461 1462 case COMPOUND_EXPR: 1463 return is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 1)); 1464 1465 case MODIFY_EXPR: 1466 case SAVE_EXPR: 1467 return is_bitfield_expr_with_lowered_type (TREE_OPERAND (exp, 0)); 1468 1469 case COMPONENT_REF: 1470 { 1471 tree field; 1472 1473 field = TREE_OPERAND (exp, 1); 1474 if (TREE_CODE (field) != FIELD_DECL || !DECL_C_BIT_FIELD (field)) 1475 return NULL_TREE; 1476 if (same_type_ignoring_top_level_qualifiers_p 1477 (TREE_TYPE (exp), DECL_BIT_FIELD_TYPE (field))) 1478 return NULL_TREE; 1479 return DECL_BIT_FIELD_TYPE (field); 1480 } 1481 1482 default: 1483 return NULL_TREE; 1484 } 1485} 1486 1487/* Like is_bitfield_with_lowered_type, except that if EXP is not a 1488 bitfield with a lowered type, the type of EXP is returned, rather 1489 than NULL_TREE. */ 1490 1491tree 1492unlowered_expr_type (tree exp) 1493{ 1494 tree type; 1495 1496 type = is_bitfield_expr_with_lowered_type (exp); 1497 if (!type) 1498 type = TREE_TYPE (exp); 1499 1500 return type; 1501} 1502 1503/* Perform the conversions in [expr] that apply when an lvalue appears 1504 in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and 1505 function-to-pointer conversions. In addition, manifest constants 1506 are replaced by their values, and bitfield references are converted 1507 to their declared types. 1508 1509 Although the returned value is being used as an rvalue, this 1510 function does not wrap the returned expression in a 1511 NON_LVALUE_EXPR; the caller is expected to be mindful of the fact 1512 that the return value is no longer an lvalue. */ 1513 1514tree 1515decay_conversion (tree exp) 1516{ 1517 tree type; 1518 enum tree_code code; 1519 1520 type = TREE_TYPE (exp); 1521 if (type == error_mark_node) 1522 return error_mark_node; 1523 1524 if (type_unknown_p (exp)) 1525 { 1526 cxx_incomplete_type_error (exp, TREE_TYPE (exp)); 1527 return error_mark_node; 1528 } 1529 1530 exp = decl_constant_value (exp); 1531 if (error_operand_p (exp)) 1532 return error_mark_node; 1533 1534 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 1535 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */ 1536 code = TREE_CODE (type); 1537 if (code == VOID_TYPE) 1538 { 1539 error ("void value not ignored as it ought to be"); 1540 return error_mark_node; 1541 } 1542 if (invalid_nonstatic_memfn_p (exp)) 1543 return error_mark_node; 1544 if (code == FUNCTION_TYPE || is_overloaded_fn (exp)) 1545 return build_unary_op (ADDR_EXPR, exp, 0); 1546 if (code == ARRAY_TYPE) 1547 { 1548 tree adr; 1549 tree ptrtype; 1550 1551 if (TREE_CODE (exp) == INDIRECT_REF) 1552 return build_nop (build_pointer_type (TREE_TYPE (type)), 1553 TREE_OPERAND (exp, 0)); 1554 1555 if (TREE_CODE (exp) == COMPOUND_EXPR) 1556 { 1557 tree op1 = decay_conversion (TREE_OPERAND (exp, 1)); 1558 return build2 (COMPOUND_EXPR, TREE_TYPE (op1), 1559 TREE_OPERAND (exp, 0), op1); 1560 } 1561 1562 if (!lvalue_p (exp) 1563 && ! (TREE_CODE (exp) == CONSTRUCTOR && TREE_STATIC (exp))) 1564 { 1565 error ("invalid use of non-lvalue array"); 1566 return error_mark_node; 1567 } 1568 1569 ptrtype = build_pointer_type (TREE_TYPE (type)); 1570 1571 if (TREE_CODE (exp) == VAR_DECL) 1572 { 1573 if (!cxx_mark_addressable (exp)) 1574 return error_mark_node; 1575 adr = build_nop (ptrtype, build_address (exp)); 1576 return adr; 1577 } 1578 /* This way is better for a COMPONENT_REF since it can 1579 simplify the offset for a component. */ 1580 adr = build_unary_op (ADDR_EXPR, exp, 1); 1581 return cp_convert (ptrtype, adr); 1582 } 1583 1584 /* If a bitfield is used in a context where integral promotion 1585 applies, then the caller is expected to have used 1586 default_conversion. That function promotes bitfields correctly 1587 before calling this function. At this point, if we have a 1588 bitfield referenced, we may assume that is not subject to 1589 promotion, and that, therefore, the type of the resulting rvalue 1590 is the declared type of the bitfield. */ 1591 exp = convert_bitfield_to_declared_type (exp); 1592 1593 /* We do not call rvalue() here because we do not want to wrap EXP 1594 in a NON_LVALUE_EXPR. */ 1595 1596 /* [basic.lval] 1597 1598 Non-class rvalues always have cv-unqualified types. */ 1599 type = TREE_TYPE (exp); 1600 if (!CLASS_TYPE_P (type) && cp_type_quals (type)) 1601 exp = build_nop (TYPE_MAIN_VARIANT (type), exp); 1602 1603 return exp; 1604} 1605 1606/* Perform prepatory conversions, as part of the "usual arithmetic 1607 conversions". In particular, as per [expr]: 1608 1609 Whenever an lvalue expression appears as an operand of an 1610 operator that expects the rvalue for that operand, the 1611 lvalue-to-rvalue, array-to-pointer, or function-to-pointer 1612 standard conversions are applied to convert the expression to an 1613 rvalue. 1614 1615 In addition, we perform integral promotions here, as those are 1616 applied to both operands to a binary operator before determining 1617 what additional conversions should apply. */ 1618 1619tree 1620default_conversion (tree exp) 1621{ 1622 /* Perform the integral promotions first so that bitfield 1623 expressions (which may promote to "int", even if the bitfield is 1624 declared "unsigned") are promoted correctly. */ 1625 if (INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (exp))) 1626 exp = perform_integral_promotions (exp); 1627 /* Perform the other conversions. */ 1628 exp = decay_conversion (exp); 1629 1630 return exp; 1631} 1632 1633/* EXPR is an expression with an integral or enumeration type. 1634 Perform the integral promotions in [conv.prom], and return the 1635 converted value. */ 1636 1637tree 1638perform_integral_promotions (tree expr) 1639{ 1640 tree type; 1641 tree promoted_type; 1642 1643 /* [conv.prom] 1644 1645 If the bitfield has an enumerated type, it is treated as any 1646 other value of that type for promotion purposes. */ 1647 type = is_bitfield_expr_with_lowered_type (expr); 1648 if (!type || TREE_CODE (type) != ENUMERAL_TYPE) 1649 type = TREE_TYPE (expr); 1650 gcc_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type)); 1651 promoted_type = type_promotes_to (type); 1652 if (type != promoted_type) 1653 expr = cp_convert (promoted_type, expr); 1654 return expr; 1655} 1656 1657/* Take the address of an inline function without setting TREE_ADDRESSABLE 1658 or TREE_USED. */ 1659 1660tree 1661inline_conversion (tree exp) 1662{ 1663 if (TREE_CODE (exp) == FUNCTION_DECL) 1664 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp); 1665 1666 return exp; 1667} 1668 1669/* Returns nonzero iff exp is a STRING_CST or the result of applying 1670 decay_conversion to one. */ 1671 1672int 1673string_conv_p (tree totype, tree exp, int warn) 1674{ 1675 tree t; 1676 1677 if (TREE_CODE (totype) != POINTER_TYPE) 1678 return 0; 1679 1680 t = TREE_TYPE (totype); 1681 if (!same_type_p (t, char_type_node) 1682 && !same_type_p (t, wchar_type_node)) 1683 return 0; 1684 1685 if (TREE_CODE (exp) == STRING_CST) 1686 { 1687 /* Make sure that we don't try to convert between char and wchar_t. */ 1688 if (!same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (exp))), t)) 1689 return 0; 1690 } 1691 else 1692 { 1693 /* Is this a string constant which has decayed to 'const char *'? */ 1694 t = build_pointer_type (build_qualified_type (t, TYPE_QUAL_CONST)); 1695 if (!same_type_p (TREE_TYPE (exp), t)) 1696 return 0; 1697 STRIP_NOPS (exp); 1698 if (TREE_CODE (exp) != ADDR_EXPR 1699 || TREE_CODE (TREE_OPERAND (exp, 0)) != STRING_CST) 1700 return 0; 1701 } 1702 1703 /* This warning is not very useful, as it complains about printf. */ 1704 if (warn) 1705 warning (OPT_Wwrite_strings, 1706 "deprecated conversion from string constant to %qT", 1707 totype); 1708 1709 return 1; 1710} 1711 1712/* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we 1713 can, for example, use as an lvalue. This code used to be in 1714 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c' 1715 expressions, where we're dealing with aggregates. But now it's again only 1716 called from unary_complex_lvalue. The case (in particular) that led to 1717 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd 1718 get it there. */ 1719 1720static tree 1721rationalize_conditional_expr (enum tree_code code, tree t) 1722{ 1723 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that 1724 the first operand is always the one to be used if both operands 1725 are equal, so we know what conditional expression this used to be. */ 1726 if (TREE_CODE (t) == MIN_EXPR || TREE_CODE (t) == MAX_EXPR) 1727 { 1728 tree op0 = TREE_OPERAND (t, 0); 1729 tree op1 = TREE_OPERAND (t, 1); 1730 1731 /* The following code is incorrect if either operand side-effects. */ 1732 gcc_assert (!TREE_SIDE_EFFECTS (op0) 1733 && !TREE_SIDE_EFFECTS (op1)); 1734 return 1735 build_conditional_expr (build_x_binary_op ((TREE_CODE (t) == MIN_EXPR 1736 ? LE_EXPR : GE_EXPR), 1737 op0, TREE_CODE (op0), 1738 op1, TREE_CODE (op1), 1739 /*overloaded_p=*/NULL), 1740 build_unary_op (code, op0, 0), 1741 build_unary_op (code, op1, 0)); 1742 } 1743 1744 return 1745 build_conditional_expr (TREE_OPERAND (t, 0), 1746 build_unary_op (code, TREE_OPERAND (t, 1), 0), 1747 build_unary_op (code, TREE_OPERAND (t, 2), 0)); 1748} 1749 1750/* Given the TYPE of an anonymous union field inside T, return the 1751 FIELD_DECL for the field. If not found return NULL_TREE. Because 1752 anonymous unions can nest, we must also search all anonymous unions 1753 that are directly reachable. */ 1754 1755tree 1756lookup_anon_field (tree t, tree type) 1757{ 1758 tree field; 1759 1760 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field)) 1761 { 1762 if (TREE_STATIC (field)) 1763 continue; 1764 if (TREE_CODE (field) != FIELD_DECL || DECL_ARTIFICIAL (field)) 1765 continue; 1766 1767 /* If we find it directly, return the field. */ 1768 if (DECL_NAME (field) == NULL_TREE 1769 && type == TYPE_MAIN_VARIANT (TREE_TYPE (field))) 1770 { 1771 return field; 1772 } 1773 1774 /* Otherwise, it could be nested, search harder. */ 1775 if (DECL_NAME (field) == NULL_TREE 1776 && ANON_AGGR_TYPE_P (TREE_TYPE (field))) 1777 { 1778 tree subfield = lookup_anon_field (TREE_TYPE (field), type); 1779 if (subfield) 1780 return subfield; 1781 } 1782 } 1783 return NULL_TREE; 1784} 1785 1786/* Build an expression representing OBJECT.MEMBER. OBJECT is an 1787 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is 1788 non-NULL, it indicates the path to the base used to name MEMBER. 1789 If PRESERVE_REFERENCE is true, the expression returned will have 1790 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression 1791 returned will have the type referred to by the reference. 1792 1793 This function does not perform access control; that is either done 1794 earlier by the parser when the name of MEMBER is resolved to MEMBER 1795 itself, or later when overload resolution selects one of the 1796 functions indicated by MEMBER. */ 1797 1798tree 1799build_class_member_access_expr (tree object, tree member, 1800 tree access_path, bool preserve_reference) 1801{ 1802 tree object_type; 1803 tree member_scope; 1804 tree result = NULL_TREE; 1805 1806 if (error_operand_p (object) || error_operand_p (member)) 1807 return error_mark_node; 1808 1809 gcc_assert (DECL_P (member) || BASELINK_P (member)); 1810 1811 /* [expr.ref] 1812 1813 The type of the first expression shall be "class object" (of a 1814 complete type). */ 1815 object_type = TREE_TYPE (object); 1816 if (!currently_open_class (object_type) 1817 && !complete_type_or_else (object_type, object)) 1818 return error_mark_node; 1819 if (!CLASS_TYPE_P (object_type)) 1820 { 1821 error ("request for member %qD in %qE, which is of non-class type %qT", 1822 member, object, object_type); 1823 return error_mark_node; 1824 } 1825 1826 /* The standard does not seem to actually say that MEMBER must be a 1827 member of OBJECT_TYPE. However, that is clearly what is 1828 intended. */ 1829 if (DECL_P (member)) 1830 { 1831 member_scope = DECL_CLASS_CONTEXT (member); 1832 mark_used (member); 1833 if (TREE_DEPRECATED (member)) 1834 warn_deprecated_use (member); 1835 } 1836 else 1837 member_scope = BINFO_TYPE (BASELINK_BINFO (member)); 1838 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will 1839 presently be the anonymous union. Go outwards until we find a 1840 type related to OBJECT_TYPE. */ 1841 while (ANON_AGGR_TYPE_P (member_scope) 1842 && !same_type_ignoring_top_level_qualifiers_p (member_scope, 1843 object_type)) 1844 member_scope = TYPE_CONTEXT (member_scope); 1845 if (!member_scope || !DERIVED_FROM_P (member_scope, object_type)) 1846 { 1847 if (TREE_CODE (member) == FIELD_DECL) 1848 error ("invalid use of nonstatic data member %qE", member); 1849 else 1850 error ("%qD is not a member of %qT", member, object_type); 1851 return error_mark_node; 1852 } 1853 1854 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into 1855 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue 1856 in the frontend; only _DECLs and _REFs are lvalues in the backend. */ 1857 { 1858 tree temp = unary_complex_lvalue (ADDR_EXPR, object); 1859 if (temp) 1860 object = build_indirect_ref (temp, NULL); 1861 } 1862 1863 /* In [expr.ref], there is an explicit list of the valid choices for 1864 MEMBER. We check for each of those cases here. */ 1865 if (TREE_CODE (member) == VAR_DECL) 1866 { 1867 /* A static data member. */ 1868 result = member; 1869 /* If OBJECT has side-effects, they are supposed to occur. */ 1870 if (TREE_SIDE_EFFECTS (object)) 1871 result = build2 (COMPOUND_EXPR, TREE_TYPE (result), object, result); 1872 } 1873 else if (TREE_CODE (member) == FIELD_DECL) 1874 { 1875 /* A non-static data member. */ 1876 bool null_object_p; 1877 int type_quals; 1878 tree member_type; 1879 1880 null_object_p = (TREE_CODE (object) == INDIRECT_REF 1881 && integer_zerop (TREE_OPERAND (object, 0))); 1882 1883 /* Convert OBJECT to the type of MEMBER. */ 1884 if (!same_type_p (TYPE_MAIN_VARIANT (object_type), 1885 TYPE_MAIN_VARIANT (member_scope))) 1886 { 1887 tree binfo; 1888 base_kind kind; 1889 1890 binfo = lookup_base (access_path ? access_path : object_type, 1891 member_scope, ba_unique, &kind); 1892 if (binfo == error_mark_node) 1893 return error_mark_node; 1894 1895 /* It is invalid to try to get to a virtual base of a 1896 NULL object. The most common cause is invalid use of 1897 offsetof macro. */ 1898 if (null_object_p && kind == bk_via_virtual) 1899 { 1900 error ("invalid access to non-static data member %qD of " 1901 "NULL object", 1902 member); 1903 error ("(perhaps the %<offsetof%> macro was used incorrectly)"); 1904 return error_mark_node; 1905 } 1906 1907 /* Convert to the base. */ 1908 object = build_base_path (PLUS_EXPR, object, binfo, 1909 /*nonnull=*/1); 1910 /* If we found the base successfully then we should be able 1911 to convert to it successfully. */ 1912 gcc_assert (object != error_mark_node); 1913 } 1914 1915 /* Complain about other invalid uses of offsetof, even though they will 1916 give the right answer. Note that we complain whether or not they 1917 actually used the offsetof macro, since there's no way to know at this 1918 point. So we just give a warning, instead of a pedwarn. */ 1919 /* Do not produce this warning for base class field references, because 1920 we know for a fact that didn't come from offsetof. This does occur 1921 in various testsuite cases where a null object is passed where a 1922 vtable access is required. */ 1923 if (null_object_p && warn_invalid_offsetof 1924 && CLASSTYPE_NON_POD_P (object_type) 1925 && !DECL_FIELD_IS_BASE (member) 1926 && !skip_evaluation) 1927 { 1928 warning (0, "invalid access to non-static data member %qD of NULL object", 1929 member); 1930 warning (0, "(perhaps the %<offsetof%> macro was used incorrectly)"); 1931 } 1932 1933 /* If MEMBER is from an anonymous aggregate, we have converted 1934 OBJECT so that it refers to the class containing the 1935 anonymous union. Generate a reference to the anonymous union 1936 itself, and recur to find MEMBER. */ 1937 if (ANON_AGGR_TYPE_P (DECL_CONTEXT (member)) 1938 /* When this code is called from build_field_call, the 1939 object already has the type of the anonymous union. 1940 That is because the COMPONENT_REF was already 1941 constructed, and was then disassembled before calling 1942 build_field_call. After the function-call code is 1943 cleaned up, this waste can be eliminated. */ 1944 && (!same_type_ignoring_top_level_qualifiers_p 1945 (TREE_TYPE (object), DECL_CONTEXT (member)))) 1946 { 1947 tree anonymous_union; 1948 1949 anonymous_union = lookup_anon_field (TREE_TYPE (object), 1950 DECL_CONTEXT (member)); 1951 object = build_class_member_access_expr (object, 1952 anonymous_union, 1953 /*access_path=*/NULL_TREE, 1954 preserve_reference); 1955 } 1956 1957 /* Compute the type of the field, as described in [expr.ref]. */ 1958 type_quals = TYPE_UNQUALIFIED; 1959 member_type = TREE_TYPE (member); 1960 if (TREE_CODE (member_type) != REFERENCE_TYPE) 1961 { 1962 type_quals = (cp_type_quals (member_type) 1963 | cp_type_quals (object_type)); 1964 1965 /* A field is const (volatile) if the enclosing object, or the 1966 field itself, is const (volatile). But, a mutable field is 1967 not const, even within a const object. */ 1968 if (DECL_MUTABLE_P (member)) 1969 type_quals &= ~TYPE_QUAL_CONST; 1970 member_type = cp_build_qualified_type (member_type, type_quals); 1971 } 1972 1973 result = build3 (COMPONENT_REF, member_type, object, member, 1974 NULL_TREE); 1975 result = fold_if_not_in_template (result); 1976 1977 /* Mark the expression const or volatile, as appropriate. Even 1978 though we've dealt with the type above, we still have to mark the 1979 expression itself. */ 1980 if (type_quals & TYPE_QUAL_CONST) 1981 TREE_READONLY (result) = 1; 1982 if (type_quals & TYPE_QUAL_VOLATILE) 1983 TREE_THIS_VOLATILE (result) = 1; 1984 } 1985 else if (BASELINK_P (member)) 1986 { 1987 /* The member is a (possibly overloaded) member function. */ 1988 tree functions; 1989 tree type; 1990 1991 /* If the MEMBER is exactly one static member function, then we 1992 know the type of the expression. Otherwise, we must wait 1993 until overload resolution has been performed. */ 1994 functions = BASELINK_FUNCTIONS (member); 1995 if (TREE_CODE (functions) == FUNCTION_DECL 1996 && DECL_STATIC_FUNCTION_P (functions)) 1997 type = TREE_TYPE (functions); 1998 else 1999 type = unknown_type_node; 2000 /* Note that we do not convert OBJECT to the BASELINK_BINFO 2001 base. That will happen when the function is called. */ 2002 result = build3 (COMPONENT_REF, type, object, member, NULL_TREE); 2003 } 2004 else if (TREE_CODE (member) == CONST_DECL) 2005 { 2006 /* The member is an enumerator. */ 2007 result = member; 2008 /* If OBJECT has side-effects, they are supposed to occur. */ 2009 if (TREE_SIDE_EFFECTS (object)) 2010 result = build2 (COMPOUND_EXPR, TREE_TYPE (result), 2011 object, result); 2012 } 2013 else 2014 { 2015 error ("invalid use of %qD", member); 2016 return error_mark_node; 2017 } 2018 2019 if (!preserve_reference) 2020 /* [expr.ref] 2021 2022 If E2 is declared to have type "reference to T", then ... the 2023 type of E1.E2 is T. */ 2024 result = convert_from_reference (result); 2025 2026 return result; 2027} 2028 2029/* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if 2030 SCOPE is NULL, by OBJECT.~DTOR_NAME. */ 2031 2032static tree 2033lookup_destructor (tree object, tree scope, tree dtor_name) 2034{ 2035 tree object_type = TREE_TYPE (object); 2036 tree dtor_type = TREE_OPERAND (dtor_name, 0); 2037 tree expr; 2038 2039 if (scope && !check_dtor_name (scope, dtor_type)) 2040 { 2041 error ("qualified type %qT does not match destructor name ~%qT", 2042 scope, dtor_type); 2043 return error_mark_node; 2044 } 2045 if (!DERIVED_FROM_P (dtor_type, TYPE_MAIN_VARIANT (object_type))) 2046 { 2047 error ("the type being destroyed is %qT, but the destructor refers to %qT", 2048 TYPE_MAIN_VARIANT (object_type), dtor_type); 2049 return error_mark_node; 2050 } 2051 expr = lookup_member (dtor_type, complete_dtor_identifier, 2052 /*protect=*/1, /*want_type=*/false); 2053 expr = (adjust_result_of_qualified_name_lookup 2054 (expr, dtor_type, object_type)); 2055 return expr; 2056} 2057 2058/* An expression of the form "A::template B" has been resolved to 2059 DECL. Issue a diagnostic if B is not a template or template 2060 specialization. */ 2061 2062void 2063check_template_keyword (tree decl) 2064{ 2065 /* The standard says: 2066 2067 [temp.names] 2068 2069 If a name prefixed by the keyword template is not a member 2070 template, the program is ill-formed. 2071 2072 DR 228 removed the restriction that the template be a member 2073 template. 2074 2075 DR 96, if accepted would add the further restriction that explicit 2076 template arguments must be provided if the template keyword is 2077 used, but, as of 2005-10-16, that DR is still in "drafting". If 2078 this DR is accepted, then the semantic checks here can be 2079 simplified, as the entity named must in fact be a template 2080 specialization, rather than, as at present, a set of overloaded 2081 functions containing at least one template function. */ 2082 if (TREE_CODE (decl) != TEMPLATE_DECL 2083 && TREE_CODE (decl) != TEMPLATE_ID_EXPR) 2084 { 2085 if (!is_overloaded_fn (decl)) 2086 pedwarn ("%qD is not a template", decl); 2087 else 2088 { 2089 tree fns; 2090 fns = decl; 2091 if (BASELINK_P (fns)) 2092 fns = BASELINK_FUNCTIONS (fns); 2093 while (fns) 2094 { 2095 tree fn = OVL_CURRENT (fns); 2096 if (TREE_CODE (fn) == TEMPLATE_DECL 2097 || TREE_CODE (fn) == TEMPLATE_ID_EXPR) 2098 break; 2099 if (TREE_CODE (fn) == FUNCTION_DECL 2100 && DECL_USE_TEMPLATE (fn) 2101 && PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (fn))) 2102 break; 2103 fns = OVL_NEXT (fns); 2104 } 2105 if (!fns) 2106 pedwarn ("%qD is not a template", decl); 2107 } 2108 } 2109} 2110 2111/* This function is called by the parser to process a class member 2112 access expression of the form OBJECT.NAME. NAME is a node used by 2113 the parser to represent a name; it is not yet a DECL. It may, 2114 however, be a BASELINK where the BASELINK_FUNCTIONS is a 2115 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and 2116 there is no reason to do the lookup twice, so the parser keeps the 2117 BASELINK. TEMPLATE_P is true iff NAME was explicitly declared to 2118 be a template via the use of the "A::template B" syntax. */ 2119 2120tree 2121finish_class_member_access_expr (tree object, tree name, bool template_p) 2122{ 2123 tree expr; 2124 tree object_type; 2125 tree member; 2126 tree access_path = NULL_TREE; 2127 tree orig_object = object; 2128 tree orig_name = name; 2129 2130 if (object == error_mark_node || name == error_mark_node) 2131 return error_mark_node; 2132 2133 /* If OBJECT is an ObjC class instance, we must obey ObjC access rules. */ 2134 if (!objc_is_public (object, name)) 2135 return error_mark_node; 2136 2137 object_type = TREE_TYPE (object); 2138 2139 if (processing_template_decl) 2140 { 2141 if (/* If OBJECT_TYPE is dependent, so is OBJECT.NAME. */ 2142 dependent_type_p (object_type) 2143 /* If NAME is just an IDENTIFIER_NODE, then the expression 2144 is dependent. */ 2145 || TREE_CODE (object) == IDENTIFIER_NODE 2146 /* If NAME is "f<args>", where either 'f' or 'args' is 2147 dependent, then the expression is dependent. */ 2148 || (TREE_CODE (name) == TEMPLATE_ID_EXPR 2149 && dependent_template_id_p (TREE_OPERAND (name, 0), 2150 TREE_OPERAND (name, 1))) 2151 /* If NAME is "T::X" where "T" is dependent, then the 2152 expression is dependent. */ 2153 || (TREE_CODE (name) == SCOPE_REF 2154 && TYPE_P (TREE_OPERAND (name, 0)) 2155 && dependent_type_p (TREE_OPERAND (name, 0)))) 2156 return build_min_nt (COMPONENT_REF, object, name, NULL_TREE); 2157 object = build_non_dependent_expr (object); 2158 } 2159 2160 /* [expr.ref] 2161 2162 The type of the first expression shall be "class object" (of a 2163 complete type). */ 2164 if (!currently_open_class (object_type) 2165 && !complete_type_or_else (object_type, object)) 2166 return error_mark_node; 2167 if (!CLASS_TYPE_P (object_type)) 2168 { 2169 error ("request for member %qD in %qE, which is of non-class type %qT", 2170 name, object, object_type); 2171 return error_mark_node; 2172 } 2173 2174 if (BASELINK_P (name)) 2175 /* A member function that has already been looked up. */ 2176 member = name; 2177 else 2178 { 2179 bool is_template_id = false; 2180 tree template_args = NULL_TREE; 2181 tree scope; 2182 2183 if (TREE_CODE (name) == TEMPLATE_ID_EXPR) 2184 { 2185 is_template_id = true; 2186 template_args = TREE_OPERAND (name, 1); 2187 name = TREE_OPERAND (name, 0); 2188 2189 if (TREE_CODE (name) == OVERLOAD) 2190 name = DECL_NAME (get_first_fn (name)); 2191 else if (DECL_P (name)) 2192 name = DECL_NAME (name); 2193 } 2194 2195 if (TREE_CODE (name) == SCOPE_REF) 2196 { 2197 /* A qualified name. The qualifying class or namespace `S' 2198 has already been looked up; it is either a TYPE or a 2199 NAMESPACE_DECL. */ 2200 scope = TREE_OPERAND (name, 0); 2201 name = TREE_OPERAND (name, 1); 2202 2203 /* If SCOPE is a namespace, then the qualified name does not 2204 name a member of OBJECT_TYPE. */ 2205 if (TREE_CODE (scope) == NAMESPACE_DECL) 2206 { 2207 error ("%<%D::%D%> is not a member of %qT", 2208 scope, name, object_type); 2209 return error_mark_node; 2210 } 2211 2212 gcc_assert (CLASS_TYPE_P (scope)); 2213 gcc_assert (TREE_CODE (name) == IDENTIFIER_NODE 2214 || TREE_CODE (name) == BIT_NOT_EXPR); 2215 2216 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */ 2217 access_path = lookup_base (object_type, scope, ba_check, NULL); 2218 if (access_path == error_mark_node) 2219 return error_mark_node; 2220 if (!access_path) 2221 { 2222 error ("%qT is not a base of %qT", scope, object_type); 2223 return error_mark_node; 2224 } 2225 } 2226 else 2227 { 2228 scope = NULL_TREE; 2229 access_path = object_type; 2230 } 2231 2232 if (TREE_CODE (name) == BIT_NOT_EXPR) 2233 member = lookup_destructor (object, scope, name); 2234 else 2235 { 2236 /* Look up the member. */ 2237 member = lookup_member (access_path, name, /*protect=*/1, 2238 /*want_type=*/false); 2239 if (member == NULL_TREE) 2240 { 2241 error ("%qD has no member named %qE", object_type, name); 2242 return error_mark_node; 2243 } 2244 if (member == error_mark_node) 2245 return error_mark_node; 2246 } 2247 2248 if (is_template_id) 2249 { 2250 tree template = member; 2251 2252 if (BASELINK_P (template)) 2253 template = lookup_template_function (template, template_args); 2254 else 2255 { 2256 error ("%qD is not a member template function", name); 2257 return error_mark_node; 2258 } 2259 } 2260 } 2261 2262 if (TREE_DEPRECATED (member)) 2263 warn_deprecated_use (member); 2264 2265 if (template_p) 2266 check_template_keyword (member); 2267 2268 expr = build_class_member_access_expr (object, member, access_path, 2269 /*preserve_reference=*/false); 2270 if (processing_template_decl && expr != error_mark_node) 2271 { 2272 if (BASELINK_P (member)) 2273 { 2274 if (TREE_CODE (orig_name) == SCOPE_REF) 2275 BASELINK_QUALIFIED_P (member) = 1; 2276 orig_name = member; 2277 } 2278 return build_min_non_dep (COMPONENT_REF, expr, 2279 orig_object, orig_name, 2280 NULL_TREE); 2281 } 2282 2283 return expr; 2284} 2285 2286/* Return an expression for the MEMBER_NAME field in the internal 2287 representation of PTRMEM, a pointer-to-member function. (Each 2288 pointer-to-member function type gets its own RECORD_TYPE so it is 2289 more convenient to access the fields by name than by FIELD_DECL.) 2290 This routine converts the NAME to a FIELD_DECL and then creates the 2291 node for the complete expression. */ 2292 2293tree 2294build_ptrmemfunc_access_expr (tree ptrmem, tree member_name) 2295{ 2296 tree ptrmem_type; 2297 tree member; 2298 tree member_type; 2299 2300 /* This code is a stripped down version of 2301 build_class_member_access_expr. It does not work to use that 2302 routine directly because it expects the object to be of class 2303 type. */ 2304 ptrmem_type = TREE_TYPE (ptrmem); 2305 gcc_assert (TYPE_PTRMEMFUNC_P (ptrmem_type)); 2306 member = lookup_member (ptrmem_type, member_name, /*protect=*/0, 2307 /*want_type=*/false); 2308 member_type = cp_build_qualified_type (TREE_TYPE (member), 2309 cp_type_quals (ptrmem_type)); 2310 return fold_build3 (COMPONENT_REF, member_type, 2311 ptrmem, member, NULL_TREE); 2312} 2313 2314/* Given an expression PTR for a pointer, return an expression 2315 for the value pointed to. 2316 ERRORSTRING is the name of the operator to appear in error messages. 2317 2318 This function may need to overload OPERATOR_FNNAME. 2319 Must also handle REFERENCE_TYPEs for C++. */ 2320 2321tree 2322build_x_indirect_ref (tree expr, const char *errorstring) 2323{ 2324 tree orig_expr = expr; 2325 tree rval; 2326 2327 if (processing_template_decl) 2328 { 2329 if (type_dependent_expression_p (expr)) 2330 return build_min_nt (INDIRECT_REF, expr); 2331 expr = build_non_dependent_expr (expr); 2332 } 2333 2334 rval = build_new_op (INDIRECT_REF, LOOKUP_NORMAL, expr, NULL_TREE, 2335 NULL_TREE, /*overloaded_p=*/NULL); 2336 if (!rval) 2337 rval = build_indirect_ref (expr, errorstring); 2338 2339 if (processing_template_decl && rval != error_mark_node) 2340 return build_min_non_dep (INDIRECT_REF, rval, orig_expr); 2341 else 2342 return rval; 2343} 2344 2345tree 2346build_indirect_ref (tree ptr, const char *errorstring) 2347{ 2348 tree pointer, type; 2349 2350 if (ptr == error_mark_node) 2351 return error_mark_node; 2352 2353 if (ptr == current_class_ptr) 2354 return current_class_ref; 2355 2356 pointer = (TREE_CODE (TREE_TYPE (ptr)) == REFERENCE_TYPE 2357 ? ptr : decay_conversion (ptr)); 2358 type = TREE_TYPE (pointer); 2359 2360 if (POINTER_TYPE_P (type)) 2361 { 2362 /* [expr.unary.op] 2363 2364 If the type of the expression is "pointer to T," the type 2365 of the result is "T." 2366 2367 We must use the canonical variant because certain parts of 2368 the back end, like fold, do pointer comparisons between 2369 types. */ 2370 tree t = canonical_type_variant (TREE_TYPE (type)); 2371 2372 if (TREE_CODE (ptr) == CONVERT_EXPR 2373 || TREE_CODE (ptr) == NOP_EXPR 2374 || TREE_CODE (ptr) == VIEW_CONVERT_EXPR) 2375 { 2376 /* If a warning is issued, mark it to avoid duplicates from 2377 the backend. This only needs to be done at 2378 warn_strict_aliasing > 2. */ 2379 if (warn_strict_aliasing > 2) 2380 if (strict_aliasing_warning (TREE_TYPE (TREE_OPERAND (ptr, 0)), 2381 type, TREE_OPERAND (ptr, 0))) 2382 TREE_NO_WARNING (ptr) = 1; 2383 } 2384 2385 if (VOID_TYPE_P (t)) 2386 { 2387 /* A pointer to incomplete type (other than cv void) can be 2388 dereferenced [expr.unary.op]/1 */ 2389 error ("%qT is not a pointer-to-object type", type); 2390 return error_mark_node; 2391 } 2392 else if (TREE_CODE (pointer) == ADDR_EXPR 2393 && same_type_p (t, TREE_TYPE (TREE_OPERAND (pointer, 0)))) 2394 /* The POINTER was something like `&x'. We simplify `*&x' to 2395 `x'. */ 2396 return TREE_OPERAND (pointer, 0); 2397 else 2398 { 2399 tree ref = build1 (INDIRECT_REF, t, pointer); 2400 2401 /* We *must* set TREE_READONLY when dereferencing a pointer to const, 2402 so that we get the proper error message if the result is used 2403 to assign to. Also, &* is supposed to be a no-op. */ 2404 TREE_READONLY (ref) = CP_TYPE_CONST_P (t); 2405 TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); 2406 TREE_SIDE_EFFECTS (ref) 2407 = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (pointer)); 2408 return ref; 2409 } 2410 } 2411 /* `pointer' won't be an error_mark_node if we were given a 2412 pointer to member, so it's cool to check for this here. */ 2413 else if (TYPE_PTR_TO_MEMBER_P (type)) 2414 error ("invalid use of %qs on pointer to member", errorstring); 2415 else if (pointer != error_mark_node) 2416 { 2417 if (errorstring) 2418 error ("invalid type argument of %qs", errorstring); 2419 else 2420 error ("invalid type argument"); 2421 } 2422 return error_mark_node; 2423} 2424 2425/* This handles expressions of the form "a[i]", which denotes 2426 an array reference. 2427 2428 This is logically equivalent in C to *(a+i), but we may do it differently. 2429 If A is a variable or a member, we generate a primitive ARRAY_REF. 2430 This avoids forcing the array out of registers, and can work on 2431 arrays that are not lvalues (for example, members of structures returned 2432 by functions). 2433 2434 If INDEX is of some user-defined type, it must be converted to 2435 integer type. Otherwise, to make a compatible PLUS_EXPR, it 2436 will inherit the type of the array, which will be some pointer type. */ 2437 2438tree 2439build_array_ref (tree array, tree idx) 2440{ 2441 if (idx == 0) 2442 { 2443 error ("subscript missing in array reference"); 2444 return error_mark_node; 2445 } 2446 2447 if (TREE_TYPE (array) == error_mark_node 2448 || TREE_TYPE (idx) == error_mark_node) 2449 return error_mark_node; 2450 2451 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference 2452 inside it. */ 2453 switch (TREE_CODE (array)) 2454 { 2455 case COMPOUND_EXPR: 2456 { 2457 tree value = build_array_ref (TREE_OPERAND (array, 1), idx); 2458 return build2 (COMPOUND_EXPR, TREE_TYPE (value), 2459 TREE_OPERAND (array, 0), value); 2460 } 2461 2462 case COND_EXPR: 2463 return build_conditional_expr 2464 (TREE_OPERAND (array, 0), 2465 build_array_ref (TREE_OPERAND (array, 1), idx), 2466 build_array_ref (TREE_OPERAND (array, 2), idx)); 2467 2468 default: 2469 break; 2470 } 2471 2472 if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE) 2473 { 2474 tree rval, type; 2475 2476 warn_array_subscript_with_type_char (idx); 2477 2478 if (!INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (idx))) 2479 { 2480 error ("array subscript is not an integer"); 2481 return error_mark_node; 2482 } 2483 2484 /* Apply integral promotions *after* noticing character types. 2485 (It is unclear why we do these promotions -- the standard 2486 does not say that we should. In fact, the natural thing would 2487 seem to be to convert IDX to ptrdiff_t; we're performing 2488 pointer arithmetic.) */ 2489 idx = perform_integral_promotions (idx); 2490 2491 /* An array that is indexed by a non-constant 2492 cannot be stored in a register; we must be able to do 2493 address arithmetic on its address. 2494 Likewise an array of elements of variable size. */ 2495 if (TREE_CODE (idx) != INTEGER_CST 2496 || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array))) 2497 && (TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) 2498 != INTEGER_CST))) 2499 { 2500 if (!cxx_mark_addressable (array)) 2501 return error_mark_node; 2502 } 2503 2504 /* An array that is indexed by a constant value which is not within 2505 the array bounds cannot be stored in a register either; because we 2506 would get a crash in store_bit_field/extract_bit_field when trying 2507 to access a non-existent part of the register. */ 2508 if (TREE_CODE (idx) == INTEGER_CST 2509 && TYPE_DOMAIN (TREE_TYPE (array)) 2510 && ! int_fits_type_p (idx, TYPE_DOMAIN (TREE_TYPE (array)))) 2511 { 2512 if (!cxx_mark_addressable (array)) 2513 return error_mark_node; 2514 } 2515 2516 if (pedantic && !lvalue_p (array)) 2517 pedwarn ("ISO C++ forbids subscripting non-lvalue array"); 2518 2519 /* Note in C++ it is valid to subscript a `register' array, since 2520 it is valid to take the address of something with that 2521 storage specification. */ 2522 if (extra_warnings) 2523 { 2524 tree foo = array; 2525 while (TREE_CODE (foo) == COMPONENT_REF) 2526 foo = TREE_OPERAND (foo, 0); 2527 if (TREE_CODE (foo) == VAR_DECL && DECL_REGISTER (foo)) 2528 warning (OPT_Wextra, "subscripting array declared %<register%>"); 2529 } 2530 2531 type = TREE_TYPE (TREE_TYPE (array)); 2532 rval = build4 (ARRAY_REF, type, array, idx, NULL_TREE, NULL_TREE); 2533 /* Array ref is const/volatile if the array elements are 2534 or if the array is.. */ 2535 TREE_READONLY (rval) 2536 |= (CP_TYPE_CONST_P (type) | TREE_READONLY (array)); 2537 TREE_SIDE_EFFECTS (rval) 2538 |= (CP_TYPE_VOLATILE_P (type) | TREE_SIDE_EFFECTS (array)); 2539 TREE_THIS_VOLATILE (rval) 2540 |= (CP_TYPE_VOLATILE_P (type) | TREE_THIS_VOLATILE (array)); 2541 return require_complete_type (fold_if_not_in_template (rval)); 2542 } 2543 2544 { 2545 tree ar = default_conversion (array); 2546 tree ind = default_conversion (idx); 2547 2548 /* Put the integer in IND to simplify error checking. */ 2549 if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE) 2550 { 2551 tree temp = ar; 2552 ar = ind; 2553 ind = temp; 2554 } 2555 2556 if (ar == error_mark_node) 2557 return ar; 2558 2559 if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE) 2560 { 2561 error ("subscripted value is neither array nor pointer"); 2562 return error_mark_node; 2563 } 2564 if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE) 2565 { 2566 error ("array subscript is not an integer"); 2567 return error_mark_node; 2568 } 2569 2570 return build_indirect_ref (cp_build_binary_op (PLUS_EXPR, ar, ind), 2571 "array indexing"); 2572 } 2573} 2574 2575/* Resolve a pointer to member function. INSTANCE is the object 2576 instance to use, if the member points to a virtual member. 2577 2578 This used to avoid checking for virtual functions if basetype 2579 has no virtual functions, according to an earlier ANSI draft. 2580 With the final ISO C++ rules, such an optimization is 2581 incorrect: A pointer to a derived member can be static_cast 2582 to pointer-to-base-member, as long as the dynamic object 2583 later has the right member. */ 2584 2585tree 2586get_member_function_from_ptrfunc (tree *instance_ptrptr, tree function) 2587{ 2588 if (TREE_CODE (function) == OFFSET_REF) 2589 function = TREE_OPERAND (function, 1); 2590 2591 if (TYPE_PTRMEMFUNC_P (TREE_TYPE (function))) 2592 { 2593 tree idx, delta, e1, e2, e3, vtbl, basetype; 2594 tree fntype = TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (function)); 2595 2596 tree instance_ptr = *instance_ptrptr; 2597 tree instance_save_expr = 0; 2598 if (instance_ptr == error_mark_node) 2599 { 2600 if (TREE_CODE (function) == PTRMEM_CST) 2601 { 2602 /* Extracting the function address from a pmf is only 2603 allowed with -Wno-pmf-conversions. It only works for 2604 pmf constants. */ 2605 e1 = build_addr_func (PTRMEM_CST_MEMBER (function)); 2606 e1 = convert (fntype, e1); 2607 return e1; 2608 } 2609 else 2610 { 2611 error ("object missing in use of %qE", function); 2612 return error_mark_node; 2613 } 2614 } 2615 2616 if (TREE_SIDE_EFFECTS (instance_ptr)) 2617 instance_ptr = instance_save_expr = save_expr (instance_ptr); 2618 2619 if (TREE_SIDE_EFFECTS (function)) 2620 function = save_expr (function); 2621 2622 /* Start by extracting all the information from the PMF itself. */ 2623 e3 = pfn_from_ptrmemfunc (function); 2624 delta = build_ptrmemfunc_access_expr (function, delta_identifier); 2625 idx = build1 (NOP_EXPR, vtable_index_type, e3); 2626 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION) 2627 { 2628 case ptrmemfunc_vbit_in_pfn: 2629 e1 = cp_build_binary_op (BIT_AND_EXPR, idx, integer_one_node); 2630 idx = cp_build_binary_op (MINUS_EXPR, idx, integer_one_node); 2631 break; 2632 2633 case ptrmemfunc_vbit_in_delta: 2634 e1 = cp_build_binary_op (BIT_AND_EXPR, delta, integer_one_node); 2635 delta = cp_build_binary_op (RSHIFT_EXPR, delta, integer_one_node); 2636 break; 2637 2638 default: 2639 gcc_unreachable (); 2640 } 2641 2642 /* Convert down to the right base before using the instance. A 2643 special case is that in a pointer to member of class C, C may 2644 be incomplete. In that case, the function will of course be 2645 a member of C, and no conversion is required. In fact, 2646 lookup_base will fail in that case, because incomplete 2647 classes do not have BINFOs. */ 2648 basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (fntype)); 2649 if (!same_type_ignoring_top_level_qualifiers_p 2650 (basetype, TREE_TYPE (TREE_TYPE (instance_ptr)))) 2651 { 2652 basetype = lookup_base (TREE_TYPE (TREE_TYPE (instance_ptr)), 2653 basetype, ba_check, NULL); 2654 instance_ptr = build_base_path (PLUS_EXPR, instance_ptr, basetype, 2655 1); 2656 if (instance_ptr == error_mark_node) 2657 return error_mark_node; 2658 } 2659 /* ...and then the delta in the PMF. */ 2660 instance_ptr = build2 (PLUS_EXPR, TREE_TYPE (instance_ptr), 2661 instance_ptr, delta); 2662 2663 /* Hand back the adjusted 'this' argument to our caller. */ 2664 *instance_ptrptr = instance_ptr; 2665 2666 /* Next extract the vtable pointer from the object. */ 2667 vtbl = build1 (NOP_EXPR, build_pointer_type (vtbl_ptr_type_node), 2668 instance_ptr); 2669 vtbl = build_indirect_ref (vtbl, NULL); 2670 2671 /* Finally, extract the function pointer from the vtable. */ 2672 e2 = fold_build2 (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, idx); 2673 e2 = build_indirect_ref (e2, NULL); 2674 TREE_CONSTANT (e2) = 1; 2675 TREE_INVARIANT (e2) = 1; 2676 2677 /* When using function descriptors, the address of the 2678 vtable entry is treated as a function pointer. */ 2679 if (TARGET_VTABLE_USES_DESCRIPTORS) 2680 e2 = build1 (NOP_EXPR, TREE_TYPE (e2), 2681 build_unary_op (ADDR_EXPR, e2, /*noconvert=*/1)); 2682 2683 TREE_TYPE (e2) = TREE_TYPE (e3); 2684 e1 = build_conditional_expr (e1, e2, e3); 2685 2686 /* Make sure this doesn't get evaluated first inside one of the 2687 branches of the COND_EXPR. */ 2688 if (instance_save_expr) 2689 e1 = build2 (COMPOUND_EXPR, TREE_TYPE (e1), 2690 instance_save_expr, e1); 2691 2692 function = e1; 2693 } 2694 return function; 2695} 2696 2697/* APPLE LOCAL begin blocks 6040305 (cm) */ 2698/* APPLE LOCAL begin radar 5847213 - radar 6329245 */ 2699/** 2700 build_block_call - Routine to build a block call; as in: 2701 ((double(*)(void *, int))(BLOCK_PTR_EXP->__FuncPtr))(I, 42); 2702 FNTYPE is the original function type derived from the syntax. 2703 BLOCK_PTR_EXP is the block pointer variable. 2704 PARAMS is the parameter list. 2705*/ 2706static tree 2707build_block_call (tree fntype, tree block_ptr_exp, tree params) 2708{ 2709 tree function_ptr_exp; 2710 tree typelist; 2711 tree result; 2712 /* APPLE LOCAL radar 6396238 */ 2713 bool block_ptr_exp_side_effect = TREE_SIDE_EFFECTS (block_ptr_exp); 2714 2715 /* First convert it to 'void *'. */ 2716 block_ptr_exp = convert (ptr_type_node, block_ptr_exp); 2717 gcc_assert (generic_block_literal_struct_type); 2718 block_ptr_exp = convert (build_pointer_type (generic_block_literal_struct_type), 2719 block_ptr_exp); 2720 if (block_ptr_exp_side_effect) 2721 block_ptr_exp = save_expr (block_ptr_exp); 2722 2723 /* BLOCK_PTR_VAR->__FuncPtr */ 2724 function_ptr_exp = 2725 finish_class_member_access_expr (build_indirect_ref (block_ptr_exp, "->"), 2726 get_identifier ("__FuncPtr"), false); 2727 gcc_assert (function_ptr_exp); 2728 2729 /* Build: result_type(*)(void *, function-arg-type-list) */ 2730 typelist = TYPE_ARG_TYPES (fntype); 2731 typelist = tree_cons (NULL_TREE, ptr_type_node, typelist); 2732 fntype = build_function_type (TREE_TYPE (fntype), typelist); 2733 function_ptr_exp = convert (build_pointer_type (fntype), function_ptr_exp); 2734 params = tree_cons (NULL_TREE, block_ptr_exp, params); 2735 result = build3 (CALL_EXPR, TREE_TYPE (fntype), 2736 function_ptr_exp, params, NULL_TREE); 2737 /* FIXME: should do more from build_cxx_call */ 2738 result = convert_from_reference (result); 2739 return result; 2740} 2741/* APPLE LOCAL end radar 5847213 - radar 6329245 */ 2742/* APPLE LOCAL end blocks 6040305 (cm) */ 2743 2744tree 2745build_function_call (tree function, tree params) 2746{ 2747 tree fntype, fndecl; 2748 tree coerced_params; 2749 tree name = NULL_TREE; 2750 int is_method; 2751 tree original = function; 2752 2753 /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF 2754 expressions, like those used for ObjC messenger dispatches. */ 2755 function = objc_rewrite_function_call (function, params); 2756 2757 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 2758 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */ 2759 if (TREE_CODE (function) == NOP_EXPR 2760 && TREE_TYPE (function) == TREE_TYPE (TREE_OPERAND (function, 0))) 2761 function = TREE_OPERAND (function, 0); 2762 2763 if (TREE_CODE (function) == FUNCTION_DECL) 2764 { 2765 name = DECL_NAME (function); 2766 2767 mark_used (function); 2768 fndecl = function; 2769 2770 /* Convert anything with function type to a pointer-to-function. */ 2771 if (pedantic && DECL_MAIN_P (function)) 2772 pedwarn ("ISO C++ forbids calling %<::main%> from within program"); 2773 2774 /* Differs from default_conversion by not setting TREE_ADDRESSABLE 2775 (because calling an inline function does not mean the function 2776 needs to be separately compiled). */ 2777 2778 if (DECL_INLINE (function)) 2779 function = inline_conversion (function); 2780 else 2781 function = build_addr_func (function); 2782 } 2783 else 2784 { 2785 fndecl = NULL_TREE; 2786 2787 function = build_addr_func (function); 2788 } 2789 2790 if (function == error_mark_node) 2791 return error_mark_node; 2792 2793 fntype = TREE_TYPE (function); 2794 2795 if (TYPE_PTRMEMFUNC_P (fntype)) 2796 { 2797 error ("must use %<.*%> or %<->*%> to call pointer-to-member " 2798 "function in %<%E (...)%>", 2799 original); 2800 return error_mark_node; 2801 } 2802 2803 is_method = (TREE_CODE (fntype) == POINTER_TYPE 2804 && TREE_CODE (TREE_TYPE (fntype)) == METHOD_TYPE); 2805 2806 /* APPLE LOCAL blocks 6040305 */ 2807 if (!(((TREE_CODE (fntype) == POINTER_TYPE || TREE_CODE (fntype) == BLOCK_POINTER_TYPE) 2808 && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE) 2809 || is_method 2810 || TREE_CODE (function) == TEMPLATE_ID_EXPR)) 2811 { 2812 error ("%qE cannot be used as a function", original); 2813 return error_mark_node; 2814 } 2815 2816 /* fntype now gets the type of function pointed to. */ 2817 fntype = TREE_TYPE (fntype); 2818 2819 /* Convert the parameters to the types declared in the 2820 function prototype, or apply default promotions. */ 2821 2822 /* APPLE LOCAL begin radar 6087117 */ 2823 coerced_params = convert_arguments (TYPE_ARG_TYPES (fntype), 2824 params, fndecl, LOOKUP_NORMAL, 2825 (TREE_CODE (TREE_TYPE (function)) == BLOCK_POINTER_TYPE)); 2826 /* APPLE LOCAL end radar 6087117 */ 2827 if (coerced_params == error_mark_node) 2828 return error_mark_node; 2829 2830 /* Check for errors in format strings and inappropriately 2831 null parameters. */ 2832 2833 check_function_arguments (TYPE_ATTRIBUTES (fntype), coerced_params, 2834 TYPE_ARG_TYPES (fntype)); 2835 /* APPLE LOCAL begin blocks 6040305 */ 2836 if (TREE_CODE (TREE_TYPE (function)) == BLOCK_POINTER_TYPE) 2837 return build_block_call (fntype, function, coerced_params); 2838 /* APPLE LOCAL end blocks 6040305 */ 2839 2840 return build_cxx_call (function, coerced_params); 2841} 2842 2843/* Convert the actual parameter expressions in the list VALUES 2844 to the types in the list TYPELIST. 2845 If parmdecls is exhausted, or when an element has NULL as its type, 2846 perform the default conversions. 2847 2848 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages. 2849 2850 This is also where warnings about wrong number of args are generated. 2851 2852 Return a list of expressions for the parameters as converted. 2853 2854 Both VALUES and the returned value are chains of TREE_LIST nodes 2855 with the elements of the list in the TREE_VALUE slots of those nodes. 2856 2857 In C++, unspecified trailing parameters can be filled in with their 2858 default arguments, if such were specified. Do so here. */ 2859 2860static tree 2861/* APPLE LOCAL radar 6087117 */ 2862convert_arguments (tree typelist, tree values, tree fndecl, int flags, int block_call) 2863{ 2864 tree typetail, valtail; 2865 tree result = NULL_TREE; 2866 const char *called_thing = 0; 2867 int i = 0; 2868 2869 /* Argument passing is always copy-initialization. */ 2870 flags |= LOOKUP_ONLYCONVERTING; 2871 2872 if (fndecl) 2873 { 2874 if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE) 2875 { 2876 if (DECL_NAME (fndecl) == NULL_TREE 2877 || IDENTIFIER_HAS_TYPE_VALUE (DECL_NAME (fndecl))) 2878 called_thing = "constructor"; 2879 else 2880 called_thing = "member function"; 2881 } 2882 else 2883 called_thing = "function"; 2884 } 2885 2886 for (valtail = values, typetail = typelist; 2887 valtail; 2888 valtail = TREE_CHAIN (valtail), i++) 2889 { 2890 tree type = typetail ? TREE_VALUE (typetail) : 0; 2891 tree val = TREE_VALUE (valtail); 2892 2893 if (val == error_mark_node || type == error_mark_node) 2894 return error_mark_node; 2895 2896 if (type == void_type_node) 2897 { 2898 if (fndecl) 2899 { 2900 error ("too many arguments to %s %q+#D", called_thing, fndecl); 2901 error ("at this point in file"); 2902 } 2903 else 2904 /* APPLE LOCAL radar 6087117 */ 2905 error ("too many arguments to %s", (block_call ? "block call" : "function")); 2906 /* In case anybody wants to know if this argument 2907 list is valid. */ 2908 if (result) 2909 TREE_TYPE (tree_last (result)) = error_mark_node; 2910 break; 2911 } 2912 2913 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 2914 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */ 2915 if (TREE_CODE (val) == NOP_EXPR 2916 && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)) 2917 && (type == 0 || TREE_CODE (type) != REFERENCE_TYPE)) 2918 val = TREE_OPERAND (val, 0); 2919 2920 if (type == 0 || TREE_CODE (type) != REFERENCE_TYPE) 2921 { 2922 if (TREE_CODE (TREE_TYPE (val)) == ARRAY_TYPE 2923 || TREE_CODE (TREE_TYPE (val)) == FUNCTION_TYPE 2924 || TREE_CODE (TREE_TYPE (val)) == METHOD_TYPE) 2925 val = decay_conversion (val); 2926 } 2927 2928 if (val == error_mark_node) 2929 return error_mark_node; 2930 2931 if (type != 0) 2932 { 2933 /* Formal parm type is specified by a function prototype. */ 2934 tree parmval; 2935 2936 if (!COMPLETE_TYPE_P (complete_type (type))) 2937 { 2938 if (fndecl) 2939 error ("parameter %P of %qD has incomplete type %qT", 2940 i, fndecl, type); 2941 else 2942 error ("parameter %P has incomplete type %qT", i, type); 2943 parmval = error_mark_node; 2944 } 2945 else 2946 { 2947 parmval = convert_for_initialization 2948 (NULL_TREE, type, val, flags, 2949 "argument passing", fndecl, i); 2950 parmval = convert_for_arg_passing (type, parmval); 2951 } 2952 2953 if (parmval == error_mark_node) 2954 return error_mark_node; 2955 2956 result = tree_cons (NULL_TREE, parmval, result); 2957 } 2958 else 2959 { 2960 if (fndecl && DECL_BUILT_IN (fndecl) 2961 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P) 2962 /* Don't do ellipsis conversion for __built_in_constant_p 2963 as this will result in spurious warnings for non-POD 2964 types. */ 2965 val = require_complete_type (val); 2966 else 2967 val = convert_arg_to_ellipsis (val); 2968 2969 result = tree_cons (NULL_TREE, val, result); 2970 } 2971 2972 if (typetail) 2973 typetail = TREE_CHAIN (typetail); 2974 } 2975 2976 if (typetail != 0 && typetail != void_list_node) 2977 { 2978 /* See if there are default arguments that can be used. */ 2979 if (TREE_PURPOSE (typetail) 2980 && TREE_CODE (TREE_PURPOSE (typetail)) != DEFAULT_ARG) 2981 { 2982 for (; typetail != void_list_node; ++i) 2983 { 2984 tree parmval 2985 = convert_default_arg (TREE_VALUE (typetail), 2986 TREE_PURPOSE (typetail), 2987 fndecl, i); 2988 2989 if (parmval == error_mark_node) 2990 return error_mark_node; 2991 2992 result = tree_cons (0, parmval, result); 2993 typetail = TREE_CHAIN (typetail); 2994 /* ends with `...'. */ 2995 if (typetail == NULL_TREE) 2996 break; 2997 } 2998 } 2999 else 3000 { 3001 if (fndecl) 3002 { 3003 error ("too few arguments to %s %q+#D", called_thing, fndecl); 3004 error ("at this point in file"); 3005 } 3006 else 3007 /* APPLE LOCAL radar 6087117 */ 3008 error ("too few arguments to %s", (block_call ? "block call" : "function")); 3009 return error_mark_node; 3010 } 3011 } 3012 3013 return nreverse (result); 3014} 3015 3016/* Build a binary-operation expression, after performing default 3017 conversions on the operands. CODE is the kind of expression to build. */ 3018 3019tree 3020build_x_binary_op (enum tree_code code, tree arg1, enum tree_code arg1_code, 3021 tree arg2, enum tree_code arg2_code, bool *overloaded_p) 3022{ 3023 tree orig_arg1; 3024 tree orig_arg2; 3025 tree expr; 3026 3027 orig_arg1 = arg1; 3028 orig_arg2 = arg2; 3029 3030 if (processing_template_decl) 3031 { 3032 if (type_dependent_expression_p (arg1) 3033 || type_dependent_expression_p (arg2)) 3034 return build_min_nt (code, arg1, arg2); 3035 arg1 = build_non_dependent_expr (arg1); 3036 arg2 = build_non_dependent_expr (arg2); 3037 } 3038 3039 if (code == DOTSTAR_EXPR) 3040 expr = build_m_component_ref (arg1, arg2); 3041 else 3042 expr = build_new_op (code, LOOKUP_NORMAL, arg1, arg2, NULL_TREE, 3043 overloaded_p); 3044 3045 /* Check for cases such as x+y<<z which users are likely to 3046 misinterpret. But don't warn about obj << x + y, since that is a 3047 common idiom for I/O. */ 3048 if (warn_parentheses 3049 && !processing_template_decl 3050 && !error_operand_p (arg1) 3051 && !error_operand_p (arg2) 3052 && (code != LSHIFT_EXPR 3053 || !IS_AGGR_TYPE (TREE_TYPE (arg1)))) 3054 warn_about_parentheses (code, arg1_code, arg2_code); 3055 3056 if (processing_template_decl && expr != error_mark_node) 3057 return build_min_non_dep (code, expr, orig_arg1, orig_arg2); 3058 3059 return expr; 3060} 3061 3062/* Build a binary-operation expression without default conversions. 3063 CODE is the kind of expression to build. 3064 This function differs from `build' in several ways: 3065 the data type of the result is computed and recorded in it, 3066 warnings are generated if arg data types are invalid, 3067 special handling for addition and subtraction of pointers is known, 3068 and some optimization is done (operations on narrow ints 3069 are done in the narrower type when that gives the same result). 3070 Constant folding is also done before the result is returned. 3071 3072 Note that the operands will never have enumeral types 3073 because either they have just had the default conversions performed 3074 or they have both just been converted to some other type in which 3075 the arithmetic is to be done. 3076 3077 C++: must do special pointer arithmetic when implementing 3078 multiple inheritance, and deal with pointer to member functions. */ 3079 3080tree 3081build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1, 3082 int convert_p ATTRIBUTE_UNUSED) 3083{ 3084 tree op0, op1; 3085 enum tree_code code0, code1; 3086 tree type0, type1; 3087 const char *invalid_op_diag; 3088 3089 /* Expression code to give to the expression when it is built. 3090 Normally this is CODE, which is what the caller asked for, 3091 but in some special cases we change it. */ 3092 enum tree_code resultcode = code; 3093 3094 /* Data type in which the computation is to be performed. 3095 In the simplest cases this is the common type of the arguments. */ 3096 tree result_type = NULL; 3097 3098 /* Nonzero means operands have already been type-converted 3099 in whatever way is necessary. 3100 Zero means they need to be converted to RESULT_TYPE. */ 3101 int converted = 0; 3102 3103 /* Nonzero means create the expression with this type, rather than 3104 RESULT_TYPE. */ 3105 tree build_type = 0; 3106 3107 /* Nonzero means after finally constructing the expression 3108 convert it to this type. */ 3109 tree final_type = 0; 3110 3111 tree result; 3112 3113 /* Nonzero if this is an operation like MIN or MAX which can 3114 safely be computed in short if both args are promoted shorts. 3115 Also implies COMMON. 3116 -1 indicates a bitwise operation; this makes a difference 3117 in the exact conditions for when it is safe to do the operation 3118 in a narrower mode. */ 3119 int shorten = 0; 3120 3121 /* Nonzero if this is a comparison operation; 3122 if both args are promoted shorts, compare the original shorts. 3123 Also implies COMMON. */ 3124 int short_compare = 0; 3125 3126 /* Nonzero if this is a right-shift operation, which can be computed on the 3127 original short and then promoted if the operand is a promoted short. */ 3128 int short_shift = 0; 3129 3130 /* Nonzero means set RESULT_TYPE to the common type of the args. */ 3131 int common = 0; 3132 3133 /* True if both operands have arithmetic type. */ 3134 bool arithmetic_types_p; 3135 3136 /* Apply default conversions. */ 3137 op0 = orig_op0; 3138 op1 = orig_op1; 3139 3140 if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR 3141 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR 3142 || code == TRUTH_XOR_EXPR) 3143 { 3144 if (!really_overloaded_fn (op0)) 3145 op0 = decay_conversion (op0); 3146 if (!really_overloaded_fn (op1)) 3147 op1 = decay_conversion (op1); 3148 } 3149 else 3150 { 3151 if (!really_overloaded_fn (op0)) 3152 op0 = default_conversion (op0); 3153 if (!really_overloaded_fn (op1)) 3154 op1 = default_conversion (op1); 3155 } 3156 3157 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */ 3158 STRIP_TYPE_NOPS (op0); 3159 STRIP_TYPE_NOPS (op1); 3160 3161 /* DTRT if one side is an overloaded function, but complain about it. */ 3162 if (type_unknown_p (op0)) 3163 { 3164 tree t = instantiate_type (TREE_TYPE (op1), op0, tf_none); 3165 if (t != error_mark_node) 3166 { 3167 pedwarn ("assuming cast to type %qT from overloaded function", 3168 TREE_TYPE (t)); 3169 op0 = t; 3170 } 3171 } 3172 if (type_unknown_p (op1)) 3173 { 3174 tree t = instantiate_type (TREE_TYPE (op0), op1, tf_none); 3175 if (t != error_mark_node) 3176 { 3177 pedwarn ("assuming cast to type %qT from overloaded function", 3178 TREE_TYPE (t)); 3179 op1 = t; 3180 } 3181 } 3182 3183 type0 = TREE_TYPE (op0); 3184 type1 = TREE_TYPE (op1); 3185 3186 /* The expression codes of the data types of the arguments tell us 3187 whether the arguments are integers, floating, pointers, etc. */ 3188 code0 = TREE_CODE (type0); 3189 code1 = TREE_CODE (type1); 3190 3191 /* If an error was already reported for one of the arguments, 3192 avoid reporting another error. */ 3193 3194 if (code0 == ERROR_MARK || code1 == ERROR_MARK) 3195 return error_mark_node; 3196 3197 if ((invalid_op_diag 3198 = targetm.invalid_binary_op (code, type0, type1))) 3199 { 3200 error (invalid_op_diag, ""); 3201 return error_mark_node; 3202 } 3203 3204 switch (code) 3205 { 3206 case MINUS_EXPR: 3207 /* Subtraction of two similar pointers. 3208 We must subtract them as integers, then divide by object size. */ 3209 if (code0 == POINTER_TYPE && code1 == POINTER_TYPE 3210 && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (type0), 3211 TREE_TYPE (type1))) 3212 return pointer_diff (op0, op1, common_type (type0, type1)); 3213 /* In all other cases except pointer - int, the usual arithmetic 3214 rules aply. */ 3215 else if (!(code0 == POINTER_TYPE && code1 == INTEGER_TYPE)) 3216 { 3217 common = 1; 3218 break; 3219 } 3220 /* The pointer - int case is just like pointer + int; fall 3221 through. */ 3222 case PLUS_EXPR: 3223 if ((code0 == POINTER_TYPE || code1 == POINTER_TYPE) 3224 && (code0 == INTEGER_TYPE || code1 == INTEGER_TYPE)) 3225 { 3226 tree ptr_operand; 3227 tree int_operand; 3228 ptr_operand = ((code0 == POINTER_TYPE) ? op0 : op1); 3229 int_operand = ((code0 == INTEGER_TYPE) ? op0 : op1); 3230 if (processing_template_decl) 3231 { 3232 result_type = TREE_TYPE (ptr_operand); 3233 break; 3234 } 3235 return cp_pointer_int_sum (code, 3236 ptr_operand, 3237 int_operand); 3238 } 3239 common = 1; 3240 break; 3241 3242 case MULT_EXPR: 3243 common = 1; 3244 break; 3245 3246 case TRUNC_DIV_EXPR: 3247 case CEIL_DIV_EXPR: 3248 case FLOOR_DIV_EXPR: 3249 case ROUND_DIV_EXPR: 3250 case EXACT_DIV_EXPR: 3251 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE 3252 || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE) 3253 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 3254 || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE)) 3255 { 3256 enum tree_code tcode0 = code0, tcode1 = code1; 3257 3258 if (TREE_CODE (op1) == INTEGER_CST && integer_zerop (op1)) 3259 warning (OPT_Wdiv_by_zero, "division by zero in %<%E / 0%>", op0); 3260 else if (TREE_CODE (op1) == REAL_CST && real_zerop (op1)) 3261 warning (OPT_Wdiv_by_zero, "division by zero in %<%E / 0.%>", op0); 3262 3263 if (tcode0 == COMPLEX_TYPE || tcode0 == VECTOR_TYPE) 3264 tcode0 = TREE_CODE (TREE_TYPE (TREE_TYPE (op0))); 3265 if (tcode1 == COMPLEX_TYPE || tcode1 == VECTOR_TYPE) 3266 tcode1 = TREE_CODE (TREE_TYPE (TREE_TYPE (op1))); 3267 3268 if (!(tcode0 == INTEGER_TYPE && tcode1 == INTEGER_TYPE)) 3269 resultcode = RDIV_EXPR; 3270 else 3271 /* When dividing two signed integers, we have to promote to int. 3272 unless we divide by a constant != -1. Note that default 3273 conversion will have been performed on the operands at this 3274 point, so we have to dig out the original type to find out if 3275 it was unsigned. */ 3276 shorten = ((TREE_CODE (op0) == NOP_EXPR 3277 && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0)))) 3278 || (TREE_CODE (op1) == INTEGER_CST 3279 && ! integer_all_onesp (op1))); 3280 3281 common = 1; 3282 } 3283 break; 3284 3285 case BIT_AND_EXPR: 3286 case BIT_IOR_EXPR: 3287 case BIT_XOR_EXPR: 3288 if ((code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3289 || (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)) 3290 shorten = -1; 3291 break; 3292 3293 case TRUNC_MOD_EXPR: 3294 case FLOOR_MOD_EXPR: 3295 if (code1 == INTEGER_TYPE && integer_zerop (op1)) 3296 warning (OPT_Wdiv_by_zero, "division by zero in %<%E %% 0%>", op0); 3297 else if (code1 == REAL_TYPE && real_zerop (op1)) 3298 warning (OPT_Wdiv_by_zero, "division by zero in %<%E %% 0.%>", op0); 3299 3300 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3301 { 3302 /* Although it would be tempting to shorten always here, that loses 3303 on some targets, since the modulo instruction is undefined if the 3304 quotient can't be represented in the computation mode. We shorten 3305 only if unsigned or if dividing by something we know != -1. */ 3306 shorten = ((TREE_CODE (op0) == NOP_EXPR 3307 && TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0)))) 3308 || (TREE_CODE (op1) == INTEGER_CST 3309 && ! integer_all_onesp (op1))); 3310 common = 1; 3311 } 3312 break; 3313 3314 case TRUTH_ANDIF_EXPR: 3315 case TRUTH_ORIF_EXPR: 3316 case TRUTH_AND_EXPR: 3317 case TRUTH_OR_EXPR: 3318 result_type = boolean_type_node; 3319 break; 3320 3321 /* Shift operations: result has same type as first operand; 3322 always convert second operand to int. 3323 Also set SHORT_SHIFT if shifting rightward. */ 3324 3325 case RSHIFT_EXPR: 3326 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3327 { 3328 result_type = type0; 3329 if (TREE_CODE (op1) == INTEGER_CST) 3330 { 3331 if (tree_int_cst_lt (op1, integer_zero_node)) 3332 warning (0, "right shift count is negative"); 3333 else 3334 { 3335 if (! integer_zerop (op1)) 3336 short_shift = 1; 3337 if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 3338 warning (0, "right shift count >= width of type"); 3339 } 3340 } 3341 /* Convert the shift-count to an integer, regardless of 3342 size of value being shifted. */ 3343 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 3344 op1 = cp_convert (integer_type_node, op1); 3345 /* Avoid converting op1 to result_type later. */ 3346 converted = 1; 3347 } 3348 break; 3349 3350 case LSHIFT_EXPR: 3351 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3352 { 3353 result_type = type0; 3354 if (TREE_CODE (op1) == INTEGER_CST) 3355 { 3356 if (tree_int_cst_lt (op1, integer_zero_node)) 3357 warning (0, "left shift count is negative"); 3358 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 3359 warning (0, "left shift count >= width of type"); 3360 } 3361 /* Convert the shift-count to an integer, regardless of 3362 size of value being shifted. */ 3363 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 3364 op1 = cp_convert (integer_type_node, op1); 3365 /* Avoid converting op1 to result_type later. */ 3366 converted = 1; 3367 } 3368 break; 3369 3370 case RROTATE_EXPR: 3371 case LROTATE_EXPR: 3372 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 3373 { 3374 result_type = type0; 3375 if (TREE_CODE (op1) == INTEGER_CST) 3376 { 3377 if (tree_int_cst_lt (op1, integer_zero_node)) 3378 warning (0, "%s rotate count is negative", 3379 (code == LROTATE_EXPR) ? "left" : "right"); 3380 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 3381 warning (0, "%s rotate count >= width of type", 3382 (code == LROTATE_EXPR) ? "left" : "right"); 3383 } 3384 /* Convert the shift-count to an integer, regardless of 3385 size of value being shifted. */ 3386 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 3387 op1 = cp_convert (integer_type_node, op1); 3388 } 3389 break; 3390 3391 case EQ_EXPR: 3392 case NE_EXPR: 3393 if (code0 == REAL_TYPE || code1 == REAL_TYPE) 3394 warning (OPT_Wfloat_equal, 3395 "comparing floating point with == or != is unsafe"); 3396 if ((TREE_CODE (orig_op0) == STRING_CST && !integer_zerop (op1)) 3397 || (TREE_CODE (orig_op1) == STRING_CST && !integer_zerop (op0))) 3398 warning (OPT_Waddress, 3399 "comparison with string literal results in unspecified behaviour"); 3400 3401 build_type = boolean_type_node; 3402 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE 3403 || code0 == COMPLEX_TYPE) 3404 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 3405 || code1 == COMPLEX_TYPE)) 3406 short_compare = 1; 3407 /* APPLE LOCAL begin blocks 6040305 */ 3408 else if (((code0 == POINTER_TYPE || code0 == BLOCK_POINTER_TYPE) 3409 && (code1 == POINTER_TYPE || code1 == BLOCK_POINTER_TYPE)) 3410 || (TYPE_PTRMEM_P (type0) && TYPE_PTRMEM_P (type1))) 3411 /* APPLE LOCAL end blocks 6040305 */ 3412 result_type = composite_pointer_type (type0, type1, op0, op1, 3413 "comparison"); 3414 /* APPLE LOCAL blocks 6040305 (cl) */ 3415 else if ((code0 == POINTER_TYPE || code0 == BLOCK_POINTER_TYPE || TYPE_PTRMEM_P (type0)) 3416 && null_ptr_cst_p (op1)) 3417 result_type = type0; 3418 /* APPLE LOCAL blocks 6040305 (cl) */ 3419 else if ((code1 == POINTER_TYPE || code1 == BLOCK_POINTER_TYPE || TYPE_PTRMEM_P (type1)) 3420 && null_ptr_cst_p (op0)) 3421 result_type = type1; 3422 /* APPLE LOCAL blocks 6040305 (cl) */ 3423 else if ((code0 == POINTER_TYPE || code0 == BLOCK_POINTER_TYPE) && code1 == INTEGER_TYPE) 3424 { 3425 result_type = type0; 3426 error ("ISO C++ forbids comparison between pointer and integer"); 3427 } 3428 /* APPLE LOCAL blocks 6040305 (cl) */ 3429 else if (code0 == INTEGER_TYPE && (code1 == POINTER_TYPE || code1 == BLOCK_POINTER_TYPE)) 3430 { 3431 result_type = type1; 3432 error ("ISO C++ forbids comparison between pointer and integer"); 3433 } 3434 else if (TYPE_PTRMEMFUNC_P (type0) && null_ptr_cst_p (op1)) 3435 { 3436 op0 = build_ptrmemfunc_access_expr (op0, pfn_identifier); 3437 op1 = cp_convert (TREE_TYPE (op0), integer_zero_node); 3438 result_type = TREE_TYPE (op0); 3439 } 3440 else if (TYPE_PTRMEMFUNC_P (type1) && null_ptr_cst_p (op0)) 3441 return cp_build_binary_op (code, op1, op0); 3442 else if (TYPE_PTRMEMFUNC_P (type0) && TYPE_PTRMEMFUNC_P (type1) 3443 && same_type_p (type0, type1)) 3444 { 3445 /* E will be the final comparison. */ 3446 tree e; 3447 /* E1 and E2 are for scratch. */ 3448 tree e1; 3449 tree e2; 3450 tree pfn0; 3451 tree pfn1; 3452 tree delta0; 3453 tree delta1; 3454 3455 if (TREE_SIDE_EFFECTS (op0)) 3456 op0 = save_expr (op0); 3457 if (TREE_SIDE_EFFECTS (op1)) 3458 op1 = save_expr (op1); 3459 3460 /* We generate: 3461 3462 (op0.pfn == op1.pfn 3463 && (!op0.pfn || op0.delta == op1.delta)) 3464 3465 The reason for the `!op0.pfn' bit is that a NULL 3466 pointer-to-member is any member with a zero PFN; the 3467 DELTA field is unspecified. */ 3468 pfn0 = pfn_from_ptrmemfunc (op0); 3469 pfn1 = pfn_from_ptrmemfunc (op1); 3470 delta0 = build_ptrmemfunc_access_expr (op0, 3471 delta_identifier); 3472 delta1 = build_ptrmemfunc_access_expr (op1, 3473 delta_identifier); 3474 e1 = cp_build_binary_op (EQ_EXPR, delta0, delta1); 3475 e2 = cp_build_binary_op (EQ_EXPR, 3476 pfn0, 3477 cp_convert (TREE_TYPE (pfn0), 3478 integer_zero_node)); 3479 e1 = cp_build_binary_op (TRUTH_ORIF_EXPR, e1, e2); 3480 e2 = build2 (EQ_EXPR, boolean_type_node, pfn0, pfn1); 3481 e = cp_build_binary_op (TRUTH_ANDIF_EXPR, e2, e1); 3482 if (code == EQ_EXPR) 3483 return e; 3484 return cp_build_binary_op (EQ_EXPR, e, integer_zero_node); 3485 } 3486 else 3487 { 3488 gcc_assert (!TYPE_PTRMEMFUNC_P (type0) 3489 || !same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type0), 3490 type1)); 3491 gcc_assert (!TYPE_PTRMEMFUNC_P (type1) 3492 || !same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type1), 3493 type0)); 3494 } 3495 3496 break; 3497 3498 case MAX_EXPR: 3499 case MIN_EXPR: 3500 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE) 3501 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE)) 3502 shorten = 1; 3503 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3504 result_type = composite_pointer_type (type0, type1, op0, op1, 3505 "comparison"); 3506 break; 3507 3508 case LE_EXPR: 3509 case GE_EXPR: 3510 case LT_EXPR: 3511 case GT_EXPR: 3512 if (TREE_CODE (orig_op0) == STRING_CST 3513 || TREE_CODE (orig_op1) == STRING_CST) 3514 warning (OPT_Waddress, 3515 "comparison with string literal results in unspecified behaviour"); 3516 3517 build_type = boolean_type_node; 3518 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE) 3519 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE)) 3520 short_compare = 1; 3521 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3522 result_type = composite_pointer_type (type0, type1, op0, op1, 3523 "comparison"); 3524 else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST 3525 && integer_zerop (op1)) 3526 result_type = type0; 3527 else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST 3528 && integer_zerop (op0)) 3529 result_type = type1; 3530 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE) 3531 { 3532 result_type = type0; 3533 pedwarn ("ISO C++ forbids comparison between pointer and integer"); 3534 } 3535 else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE) 3536 { 3537 result_type = type1; 3538 pedwarn ("ISO C++ forbids comparison between pointer and integer"); 3539 } 3540 break; 3541 3542 case UNORDERED_EXPR: 3543 case ORDERED_EXPR: 3544 case UNLT_EXPR: 3545 case UNLE_EXPR: 3546 case UNGT_EXPR: 3547 case UNGE_EXPR: 3548 case UNEQ_EXPR: 3549 build_type = integer_type_node; 3550 if (code0 != REAL_TYPE || code1 != REAL_TYPE) 3551 { 3552 error ("unordered comparison on non-floating point argument"); 3553 return error_mark_node; 3554 } 3555 common = 1; 3556 break; 3557 3558 default: 3559 break; 3560 } 3561 3562 if (((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE) 3563 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 3564 || code1 == COMPLEX_TYPE))) 3565 arithmetic_types_p = 1; 3566 else 3567 { 3568 arithmetic_types_p = 0; 3569 /* Vector arithmetic is only allowed when both sides are vectors. */ 3570 if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE) 3571 { 3572 if (!tree_int_cst_equal (TYPE_SIZE (type0), TYPE_SIZE (type1)) 3573 || !same_scalar_type_ignoring_signedness (TREE_TYPE (type0), 3574 TREE_TYPE (type1))) 3575 { 3576 binary_op_error (code, type0, type1); 3577 return error_mark_node; 3578 } 3579 arithmetic_types_p = 1; 3580 } 3581 } 3582 /* Determine the RESULT_TYPE, if it is not already known. */ 3583 if (!result_type 3584 && arithmetic_types_p 3585 && (shorten || common || short_compare)) 3586 result_type = common_type (type0, type1); 3587 3588 if (!result_type) 3589 { 3590 error ("invalid operands of types %qT and %qT to binary %qO", 3591 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1), code); 3592 return error_mark_node; 3593 } 3594 3595 /* If we're in a template, the only thing we need to know is the 3596 RESULT_TYPE. */ 3597 if (processing_template_decl) 3598 return build2 (resultcode, 3599 build_type ? build_type : result_type, 3600 op0, op1); 3601 3602 if (arithmetic_types_p) 3603 { 3604 int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE); 3605 3606 /* For certain operations (which identify themselves by shorten != 0) 3607 if both args were extended from the same smaller type, 3608 do the arithmetic in that type and then extend. 3609 3610 shorten !=0 and !=1 indicates a bitwise operation. 3611 For them, this optimization is safe only if 3612 both args are zero-extended or both are sign-extended. 3613 Otherwise, we might change the result. 3614 Eg, (short)-1 | (unsigned short)-1 is (int)-1 3615 but calculated in (unsigned short) it would be (unsigned short)-1. */ 3616 3617 if (shorten && none_complex) 3618 { 3619 int unsigned0, unsigned1; 3620 tree arg0 = get_narrower (op0, &unsigned0); 3621 tree arg1 = get_narrower (op1, &unsigned1); 3622 /* UNS is 1 if the operation to be done is an unsigned one. */ 3623 int uns = TYPE_UNSIGNED (result_type); 3624 tree type; 3625 3626 final_type = result_type; 3627 3628 /* Handle the case that OP0 does not *contain* a conversion 3629 but it *requires* conversion to FINAL_TYPE. */ 3630 3631 if (op0 == arg0 && TREE_TYPE (op0) != final_type) 3632 unsigned0 = TYPE_UNSIGNED (TREE_TYPE (op0)); 3633 if (op1 == arg1 && TREE_TYPE (op1) != final_type) 3634 unsigned1 = TYPE_UNSIGNED (TREE_TYPE (op1)); 3635 3636 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */ 3637 3638 /* For bitwise operations, signedness of nominal type 3639 does not matter. Consider only how operands were extended. */ 3640 if (shorten == -1) 3641 uns = unsigned0; 3642 3643 /* Note that in all three cases below we refrain from optimizing 3644 an unsigned operation on sign-extended args. 3645 That would not be valid. */ 3646 3647 /* Both args variable: if both extended in same way 3648 from same width, do it in that width. 3649 Do it unsigned if args were zero-extended. */ 3650 if ((TYPE_PRECISION (TREE_TYPE (arg0)) 3651 < TYPE_PRECISION (result_type)) 3652 && (TYPE_PRECISION (TREE_TYPE (arg1)) 3653 == TYPE_PRECISION (TREE_TYPE (arg0))) 3654 && unsigned0 == unsigned1 3655 && (unsigned0 || !uns)) 3656 result_type = c_common_signed_or_unsigned_type 3657 (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1))); 3658 else if (TREE_CODE (arg0) == INTEGER_CST 3659 && (unsigned1 || !uns) 3660 && (TYPE_PRECISION (TREE_TYPE (arg1)) 3661 < TYPE_PRECISION (result_type)) 3662 && (type = c_common_signed_or_unsigned_type 3663 (unsigned1, TREE_TYPE (arg1)), 3664 int_fits_type_p (arg0, type))) 3665 result_type = type; 3666 else if (TREE_CODE (arg1) == INTEGER_CST 3667 && (unsigned0 || !uns) 3668 && (TYPE_PRECISION (TREE_TYPE (arg0)) 3669 < TYPE_PRECISION (result_type)) 3670 && (type = c_common_signed_or_unsigned_type 3671 (unsigned0, TREE_TYPE (arg0)), 3672 int_fits_type_p (arg1, type))) 3673 result_type = type; 3674 } 3675 3676 /* Shifts can be shortened if shifting right. */ 3677 3678 if (short_shift) 3679 { 3680 int unsigned_arg; 3681 tree arg0 = get_narrower (op0, &unsigned_arg); 3682 3683 final_type = result_type; 3684 3685 if (arg0 == op0 && final_type == TREE_TYPE (op0)) 3686 unsigned_arg = TYPE_UNSIGNED (TREE_TYPE (op0)); 3687 3688 if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type) 3689 /* We can shorten only if the shift count is less than the 3690 number of bits in the smaller type size. */ 3691 && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0 3692 /* If arg is sign-extended and then unsigned-shifted, 3693 we can simulate this with a signed shift in arg's type 3694 only if the extended result is at least twice as wide 3695 as the arg. Otherwise, the shift could use up all the 3696 ones made by sign-extension and bring in zeros. 3697 We can't optimize that case at all, but in most machines 3698 it never happens because available widths are 2**N. */ 3699 && (!TYPE_UNSIGNED (final_type) 3700 || unsigned_arg 3701 || (((unsigned) 2 * TYPE_PRECISION (TREE_TYPE (arg0))) 3702 <= TYPE_PRECISION (result_type)))) 3703 { 3704 /* Do an unsigned shift if the operand was zero-extended. */ 3705 result_type 3706 = c_common_signed_or_unsigned_type (unsigned_arg, 3707 TREE_TYPE (arg0)); 3708 /* Convert value-to-be-shifted to that type. */ 3709 if (TREE_TYPE (op0) != result_type) 3710 op0 = cp_convert (result_type, op0); 3711 converted = 1; 3712 } 3713 } 3714 3715 /* Comparison operations are shortened too but differently. 3716 They identify themselves by setting short_compare = 1. */ 3717 3718 if (short_compare) 3719 { 3720 /* Don't write &op0, etc., because that would prevent op0 3721 from being kept in a register. 3722 Instead, make copies of the our local variables and 3723 pass the copies by reference, then copy them back afterward. */ 3724 tree xop0 = op0, xop1 = op1, xresult_type = result_type; 3725 enum tree_code xresultcode = resultcode; 3726 tree val 3727 = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode); 3728 if (val != 0) 3729 return cp_convert (boolean_type_node, val); 3730 op0 = xop0, op1 = xop1; 3731 converted = 1; 3732 resultcode = xresultcode; 3733 } 3734 3735 if ((short_compare || code == MIN_EXPR || code == MAX_EXPR) 3736 && warn_sign_compare 3737 /* Do not warn until the template is instantiated; we cannot 3738 bound the ranges of the arguments until that point. */ 3739 && !processing_template_decl) 3740 { 3741 int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0)); 3742 int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1)); 3743 3744 int unsignedp0, unsignedp1; 3745 tree primop0 = get_narrower (op0, &unsignedp0); 3746 tree primop1 = get_narrower (op1, &unsignedp1); 3747 3748 /* Check for comparison of different enum types. */ 3749 if (TREE_CODE (TREE_TYPE (orig_op0)) == ENUMERAL_TYPE 3750 && TREE_CODE (TREE_TYPE (orig_op1)) == ENUMERAL_TYPE 3751 && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0)) 3752 != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1))) 3753 { 3754 warning (0, "comparison between types %q#T and %q#T", 3755 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1)); 3756 } 3757 3758 /* Give warnings for comparisons between signed and unsigned 3759 quantities that may fail. */ 3760 /* Do the checking based on the original operand trees, so that 3761 casts will be considered, but default promotions won't be. */ 3762 3763 /* Do not warn if the comparison is being done in a signed type, 3764 since the signed type will only be chosen if it can represent 3765 all the values of the unsigned type. */ 3766 if (!TYPE_UNSIGNED (result_type)) 3767 /* OK */; 3768 /* Do not warn if both operands are unsigned. */ 3769 else if (op0_signed == op1_signed) 3770 /* OK */; 3771 /* Do not warn if the signed quantity is an unsuffixed 3772 integer literal (or some static constant expression 3773 involving such literals or a conditional expression 3774 involving such literals) and it is non-negative. */ 3775 else if ((op0_signed && tree_expr_nonnegative_p (orig_op0)) 3776 || (op1_signed && tree_expr_nonnegative_p (orig_op1))) 3777 /* OK */; 3778 /* Do not warn if the comparison is an equality operation, 3779 the unsigned quantity is an integral constant and it does 3780 not use the most significant bit of result_type. */ 3781 else if ((resultcode == EQ_EXPR || resultcode == NE_EXPR) 3782 && ((op0_signed && TREE_CODE (orig_op1) == INTEGER_CST 3783 && int_fits_type_p (orig_op1, c_common_signed_type 3784 (result_type))) 3785 || (op1_signed && TREE_CODE (orig_op0) == INTEGER_CST 3786 && int_fits_type_p (orig_op0, c_common_signed_type 3787 (result_type))))) 3788 /* OK */; 3789 else 3790 warning (0, "comparison between signed and unsigned integer expressions"); 3791 3792 /* Warn if two unsigned values are being compared in a size 3793 larger than their original size, and one (and only one) is the 3794 result of a `~' operator. This comparison will always fail. 3795 3796 Also warn if one operand is a constant, and the constant does not 3797 have all bits set that are set in the ~ operand when it is 3798 extended. */ 3799 3800 if ((TREE_CODE (primop0) == BIT_NOT_EXPR) 3801 ^ (TREE_CODE (primop1) == BIT_NOT_EXPR)) 3802 { 3803 if (TREE_CODE (primop0) == BIT_NOT_EXPR) 3804 primop0 = get_narrower (TREE_OPERAND (op0, 0), &unsignedp0); 3805 if (TREE_CODE (primop1) == BIT_NOT_EXPR) 3806 primop1 = get_narrower (TREE_OPERAND (op1, 0), &unsignedp1); 3807 3808 if (host_integerp (primop0, 0) || host_integerp (primop1, 0)) 3809 { 3810 tree primop; 3811 HOST_WIDE_INT constant, mask; 3812 int unsignedp; 3813 unsigned int bits; 3814 3815 if (host_integerp (primop0, 0)) 3816 { 3817 primop = primop1; 3818 unsignedp = unsignedp1; 3819 constant = tree_low_cst (primop0, 0); 3820 } 3821 else 3822 { 3823 primop = primop0; 3824 unsignedp = unsignedp0; 3825 constant = tree_low_cst (primop1, 0); 3826 } 3827 3828 bits = TYPE_PRECISION (TREE_TYPE (primop)); 3829 if (bits < TYPE_PRECISION (result_type) 3830 && bits < HOST_BITS_PER_LONG && unsignedp) 3831 { 3832 mask = (~ (HOST_WIDE_INT) 0) << bits; 3833 if ((mask & constant) != mask) 3834 warning (0, "comparison of promoted ~unsigned with constant"); 3835 } 3836 } 3837 else if (unsignedp0 && unsignedp1 3838 && (TYPE_PRECISION (TREE_TYPE (primop0)) 3839 < TYPE_PRECISION (result_type)) 3840 && (TYPE_PRECISION (TREE_TYPE (primop1)) 3841 < TYPE_PRECISION (result_type))) 3842 warning (0, "comparison of promoted ~unsigned with unsigned"); 3843 } 3844 } 3845 } 3846 3847 /* If CONVERTED is zero, both args will be converted to type RESULT_TYPE. 3848 Then the expression will be built. 3849 It will be given type FINAL_TYPE if that is nonzero; 3850 otherwise, it will be given type RESULT_TYPE. */ 3851 3852 /* Issue warnings about peculiar, but valid, uses of NULL. */ 3853 if (/* It's reasonable to use pointer values as operands of && 3854 and ||, so NULL is no exception. */ 3855 !(code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR) 3856 && (/* If OP0 is NULL and OP1 is not a pointer, or vice versa. */ 3857 (orig_op0 == null_node 3858 && TREE_CODE (TREE_TYPE (op1)) != POINTER_TYPE) 3859 /* Or vice versa. */ 3860 || (orig_op1 == null_node 3861 && TREE_CODE (TREE_TYPE (op0)) != POINTER_TYPE) 3862 /* Or, both are NULL and the operation was not a comparison. */ 3863 || (orig_op0 == null_node && orig_op1 == null_node 3864 && code != EQ_EXPR && code != NE_EXPR))) 3865 /* Some sort of arithmetic operation involving NULL was 3866 performed. Note that pointer-difference and pointer-addition 3867 have already been handled above, and so we don't end up here in 3868 that case. */ 3869 warning (0, "NULL used in arithmetic"); 3870 3871 if (! converted) 3872 { 3873 if (TREE_TYPE (op0) != result_type) 3874 op0 = cp_convert (result_type, op0); 3875 if (TREE_TYPE (op1) != result_type) 3876 op1 = cp_convert (result_type, op1); 3877 3878 if (op0 == error_mark_node || op1 == error_mark_node) 3879 return error_mark_node; 3880 } 3881 3882 if (build_type == NULL_TREE) 3883 build_type = result_type; 3884 3885 result = build2 (resultcode, build_type, op0, op1); 3886 result = fold_if_not_in_template (result); 3887 if (final_type != 0) 3888 result = cp_convert (final_type, result); 3889 3890 if (TREE_OVERFLOW_P (result) 3891 && !TREE_OVERFLOW_P (op0) 3892 && !TREE_OVERFLOW_P (op1)) 3893 overflow_warning (result); 3894 3895 return result; 3896} 3897 3898/* Return a tree for the sum or difference (RESULTCODE says which) 3899 of pointer PTROP and integer INTOP. */ 3900 3901static tree 3902cp_pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop) 3903{ 3904 tree res_type = TREE_TYPE (ptrop); 3905 3906 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type) 3907 in certain circumstance (when it's valid to do so). So we need 3908 to make sure it's complete. We don't need to check here, if we 3909 can actually complete it at all, as those checks will be done in 3910 pointer_int_sum() anyway. */ 3911 complete_type (TREE_TYPE (res_type)); 3912 3913 return pointer_int_sum (resultcode, ptrop, 3914 fold_if_not_in_template (intop)); 3915} 3916 3917/* Return a tree for the difference of pointers OP0 and OP1. 3918 The resulting tree has type int. */ 3919 3920static tree 3921pointer_diff (tree op0, tree op1, tree ptrtype) 3922{ 3923 tree result; 3924 tree restype = ptrdiff_type_node; 3925 tree target_type = TREE_TYPE (ptrtype); 3926 3927 if (!complete_type_or_else (target_type, NULL_TREE)) 3928 return error_mark_node; 3929 3930 if (pedantic || warn_pointer_arith) 3931 { 3932 if (TREE_CODE (target_type) == VOID_TYPE) 3933 pedwarn ("ISO C++ forbids using pointer of type %<void *%> in subtraction"); 3934 if (TREE_CODE (target_type) == FUNCTION_TYPE) 3935 pedwarn ("ISO C++ forbids using pointer to a function in subtraction"); 3936 if (TREE_CODE (target_type) == METHOD_TYPE) 3937 pedwarn ("ISO C++ forbids using pointer to a method in subtraction"); 3938 } 3939 3940 /* First do the subtraction as integers; 3941 then drop through to build the divide operator. */ 3942 3943 op0 = cp_build_binary_op (MINUS_EXPR, 3944 cp_convert (restype, op0), 3945 cp_convert (restype, op1)); 3946 3947 /* This generates an error if op1 is a pointer to an incomplete type. */ 3948 if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (op1)))) 3949 error ("invalid use of a pointer to an incomplete type in pointer arithmetic"); 3950 3951 op1 = (TYPE_PTROB_P (ptrtype) 3952 ? size_in_bytes (target_type) 3953 : integer_one_node); 3954 3955 /* Do the division. */ 3956 3957 result = build2 (EXACT_DIV_EXPR, restype, op0, cp_convert (restype, op1)); 3958 return fold_if_not_in_template (result); 3959} 3960 3961/* Construct and perhaps optimize a tree representation 3962 for a unary operation. CODE, a tree_code, specifies the operation 3963 and XARG is the operand. */ 3964 3965tree 3966build_x_unary_op (enum tree_code code, tree xarg) 3967{ 3968 tree orig_expr = xarg; 3969 tree exp; 3970 int ptrmem = 0; 3971 3972 if (processing_template_decl) 3973 { 3974 if (type_dependent_expression_p (xarg)) 3975 return build_min_nt (code, xarg, NULL_TREE); 3976 3977 xarg = build_non_dependent_expr (xarg); 3978 } 3979 3980 exp = NULL_TREE; 3981 3982 /* [expr.unary.op] says: 3983 3984 The address of an object of incomplete type can be taken. 3985 3986 (And is just the ordinary address operator, not an overloaded 3987 "operator &".) However, if the type is a template 3988 specialization, we must complete the type at this point so that 3989 an overloaded "operator &" will be available if required. */ 3990 if (code == ADDR_EXPR 3991 && TREE_CODE (xarg) != TEMPLATE_ID_EXPR 3992 && ((CLASS_TYPE_P (TREE_TYPE (xarg)) 3993 && !COMPLETE_TYPE_P (complete_type (TREE_TYPE (xarg)))) 3994 || (TREE_CODE (xarg) == OFFSET_REF))) 3995 /* Don't look for a function. */; 3996 else 3997 exp = build_new_op (code, LOOKUP_NORMAL, xarg, NULL_TREE, NULL_TREE, 3998 /*overloaded_p=*/NULL); 3999 if (!exp && code == ADDR_EXPR) 4000 { 4001 /* A pointer to member-function can be formed only by saying 4002 &X::mf. */ 4003 if (!flag_ms_extensions && TREE_CODE (TREE_TYPE (xarg)) == METHOD_TYPE 4004 && (TREE_CODE (xarg) != OFFSET_REF || !PTRMEM_OK_P (xarg))) 4005 { 4006 if (TREE_CODE (xarg) != OFFSET_REF 4007 || !TYPE_P (TREE_OPERAND (xarg, 0))) 4008 { 4009 error ("invalid use of %qE to form a pointer-to-member-function", 4010 xarg); 4011 if (TREE_CODE (xarg) != OFFSET_REF) 4012 inform (" a qualified-id is required"); 4013 return error_mark_node; 4014 } 4015 else 4016 { 4017 error ("parentheses around %qE cannot be used to form a" 4018 " pointer-to-member-function", 4019 xarg); 4020 PTRMEM_OK_P (xarg) = 1; 4021 } 4022 } 4023 4024 if (TREE_CODE (xarg) == OFFSET_REF) 4025 { 4026 ptrmem = PTRMEM_OK_P (xarg); 4027 4028 if (!ptrmem && !flag_ms_extensions 4029 && TREE_CODE (TREE_TYPE (TREE_OPERAND (xarg, 1))) == METHOD_TYPE) 4030 { 4031 /* A single non-static member, make sure we don't allow a 4032 pointer-to-member. */ 4033 xarg = build2 (OFFSET_REF, TREE_TYPE (xarg), 4034 TREE_OPERAND (xarg, 0), 4035 ovl_cons (TREE_OPERAND (xarg, 1), NULL_TREE)); 4036 PTRMEM_OK_P (xarg) = ptrmem; 4037 } 4038 } 4039 else if (TREE_CODE (xarg) == TARGET_EXPR) 4040 warning (0, "taking address of temporary"); 4041 exp = build_unary_op (ADDR_EXPR, xarg, 0); 4042 } 4043 4044 if (processing_template_decl && exp != error_mark_node) 4045 exp = build_min_non_dep (code, exp, orig_expr, 4046 /*For {PRE,POST}{INC,DEC}REMENT_EXPR*/NULL_TREE); 4047 if (TREE_CODE (exp) == ADDR_EXPR) 4048 PTRMEM_OK_P (exp) = ptrmem; 4049 return exp; 4050} 4051 4052/* Like c_common_truthvalue_conversion, but handle pointer-to-member 4053 constants, where a null value is represented by an INTEGER_CST of 4054 -1. */ 4055 4056tree 4057cp_truthvalue_conversion (tree expr) 4058{ 4059 tree type = TREE_TYPE (expr); 4060 if (TYPE_PTRMEM_P (type)) 4061 return build_binary_op (NE_EXPR, expr, integer_zero_node, 1); 4062 else 4063 return c_common_truthvalue_conversion (expr); 4064} 4065 4066/* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */ 4067 4068tree 4069condition_conversion (tree expr) 4070{ 4071 tree t; 4072 if (processing_template_decl) 4073 return expr; 4074 t = perform_implicit_conversion (boolean_type_node, expr); 4075 t = fold_build_cleanup_point_expr (boolean_type_node, t); 4076 return t; 4077} 4078 4079/* Return an ADDR_EXPR giving the address of T. This function 4080 attempts no optimizations or simplifications; it is a low-level 4081 primitive. */ 4082 4083tree 4084build_address (tree t) 4085{ 4086 tree addr; 4087 4088 if (error_operand_p (t) || !cxx_mark_addressable (t)) 4089 return error_mark_node; 4090 4091 addr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (t)), t); 4092 4093 return addr; 4094} 4095 4096/* Return a NOP_EXPR converting EXPR to TYPE. */ 4097 4098tree 4099build_nop (tree type, tree expr) 4100{ 4101 if (type == error_mark_node || error_operand_p (expr)) 4102 return expr; 4103 return build1 (NOP_EXPR, type, expr); 4104} 4105 4106/* C++: Must handle pointers to members. 4107 4108 Perhaps type instantiation should be extended to handle conversion 4109 from aggregates to types we don't yet know we want? (Or are those 4110 cases typically errors which should be reported?) 4111 4112 NOCONVERT nonzero suppresses the default promotions 4113 (such as from short to int). */ 4114 4115tree 4116build_unary_op (enum tree_code code, tree xarg, int noconvert) 4117{ 4118 /* No default_conversion here. It causes trouble for ADDR_EXPR. */ 4119 tree arg = xarg; 4120 tree argtype = 0; 4121 const char *errstring = NULL; 4122 tree val; 4123 const char *invalid_op_diag; 4124 4125 if (arg == error_mark_node) 4126 return error_mark_node; 4127 4128 if ((invalid_op_diag 4129 = targetm.invalid_unary_op ((code == UNARY_PLUS_EXPR 4130 ? CONVERT_EXPR 4131 : code), 4132 TREE_TYPE (xarg)))) 4133 { 4134 error (invalid_op_diag, ""); 4135 return error_mark_node; 4136 } 4137 4138 switch (code) 4139 { 4140 case UNARY_PLUS_EXPR: 4141 case NEGATE_EXPR: 4142 { 4143 int flags = WANT_ARITH | WANT_ENUM; 4144 /* Unary plus (but not unary minus) is allowed on pointers. */ 4145 if (code == UNARY_PLUS_EXPR) 4146 flags |= WANT_POINTER; 4147 arg = build_expr_type_conversion (flags, arg, true); 4148 if (!arg) 4149 errstring = (code == NEGATE_EXPR 4150 ? "wrong type argument to unary minus" 4151 : "wrong type argument to unary plus"); 4152 else 4153 { 4154 if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg))) 4155 arg = perform_integral_promotions (arg); 4156 4157 /* Make sure the result is not an lvalue: a unary plus or minus 4158 expression is always a rvalue. */ 4159 arg = rvalue (arg); 4160 } 4161 } 4162 break; 4163 4164 case BIT_NOT_EXPR: 4165 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4166 { 4167 code = CONJ_EXPR; 4168 if (!noconvert) 4169 arg = default_conversion (arg); 4170 } 4171 else if (!(arg = build_expr_type_conversion (WANT_INT | WANT_ENUM 4172 | WANT_VECTOR, 4173 arg, true))) 4174 errstring = "wrong type argument to bit-complement"; 4175 else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg))) 4176 arg = perform_integral_promotions (arg); 4177 break; 4178 4179 case ABS_EXPR: 4180 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true))) 4181 errstring = "wrong type argument to abs"; 4182 else if (!noconvert) 4183 arg = default_conversion (arg); 4184 break; 4185 4186 case CONJ_EXPR: 4187 /* Conjugating a real value is a no-op, but allow it anyway. */ 4188 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true))) 4189 errstring = "wrong type argument to conjugation"; 4190 else if (!noconvert) 4191 arg = default_conversion (arg); 4192 break; 4193 4194 case TRUTH_NOT_EXPR: 4195 arg = perform_implicit_conversion (boolean_type_node, arg); 4196 val = invert_truthvalue (arg); 4197 if (arg != error_mark_node) 4198 return val; 4199 errstring = "in argument to unary !"; 4200 break; 4201 4202 case NOP_EXPR: 4203 break; 4204 4205 case REALPART_EXPR: 4206 if (TREE_CODE (arg) == COMPLEX_CST) 4207 return TREE_REALPART (arg); 4208 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4209 { 4210 arg = build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg); 4211 return fold_if_not_in_template (arg); 4212 } 4213 else 4214 return arg; 4215 4216 case IMAGPART_EXPR: 4217 if (TREE_CODE (arg) == COMPLEX_CST) 4218 return TREE_IMAGPART (arg); 4219 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4220 { 4221 arg = build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg); 4222 return fold_if_not_in_template (arg); 4223 } 4224 else 4225 return cp_convert (TREE_TYPE (arg), integer_zero_node); 4226 4227 case PREINCREMENT_EXPR: 4228 case POSTINCREMENT_EXPR: 4229 case PREDECREMENT_EXPR: 4230 case POSTDECREMENT_EXPR: 4231 /* Handle complex lvalues (when permitted) 4232 by reduction to simpler cases. */ 4233 4234 val = unary_complex_lvalue (code, arg); 4235 if (val != 0) 4236 return val; 4237 4238 /* Increment or decrement the real part of the value, 4239 and don't change the imaginary part. */ 4240 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 4241 { 4242 tree real, imag; 4243 4244 arg = stabilize_reference (arg); 4245 real = build_unary_op (REALPART_EXPR, arg, 1); 4246 imag = build_unary_op (IMAGPART_EXPR, arg, 1); 4247 return build2 (COMPLEX_EXPR, TREE_TYPE (arg), 4248 build_unary_op (code, real, 1), imag); 4249 } 4250 4251 /* Report invalid types. */ 4252 4253 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_POINTER, 4254 arg, true))) 4255 { 4256 if (code == PREINCREMENT_EXPR) 4257 errstring ="no pre-increment operator for type"; 4258 else if (code == POSTINCREMENT_EXPR) 4259 errstring ="no post-increment operator for type"; 4260 else if (code == PREDECREMENT_EXPR) 4261 errstring ="no pre-decrement operator for type"; 4262 else 4263 errstring ="no post-decrement operator for type"; 4264 break; 4265 } 4266 4267 /* Report something read-only. */ 4268 4269 if (CP_TYPE_CONST_P (TREE_TYPE (arg)) 4270 || TREE_READONLY (arg)) 4271 readonly_error (arg, ((code == PREINCREMENT_EXPR 4272 || code == POSTINCREMENT_EXPR) 4273 ? "increment" : "decrement"), 4274 0); 4275 4276 { 4277 tree inc; 4278 tree declared_type; 4279 tree result_type = TREE_TYPE (arg); 4280 4281 declared_type = unlowered_expr_type (arg); 4282 4283 arg = get_unwidened (arg, 0); 4284 argtype = TREE_TYPE (arg); 4285 4286 /* ARM $5.2.5 last annotation says this should be forbidden. */ 4287 if (TREE_CODE (argtype) == ENUMERAL_TYPE) 4288 pedwarn ("ISO C++ forbids %sing an enum", 4289 (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR) 4290 ? "increment" : "decrement"); 4291 4292 /* Compute the increment. */ 4293 4294 if (TREE_CODE (argtype) == POINTER_TYPE) 4295 { 4296 tree type = complete_type (TREE_TYPE (argtype)); 4297 4298 if (!COMPLETE_OR_VOID_TYPE_P (type)) 4299 error ("cannot %s a pointer to incomplete type %qT", 4300 ((code == PREINCREMENT_EXPR 4301 || code == POSTINCREMENT_EXPR) 4302 ? "increment" : "decrement"), TREE_TYPE (argtype)); 4303 else if ((pedantic || warn_pointer_arith) 4304 && !TYPE_PTROB_P (argtype)) 4305 pedwarn ("ISO C++ forbids %sing a pointer of type %qT", 4306 ((code == PREINCREMENT_EXPR 4307 || code == POSTINCREMENT_EXPR) 4308 ? "increment" : "decrement"), argtype); 4309 inc = cxx_sizeof_nowarn (TREE_TYPE (argtype)); 4310 } 4311 else 4312 inc = integer_one_node; 4313 4314 inc = cp_convert (argtype, inc); 4315 4316 /* Handle incrementing a cast-expression. */ 4317 4318 switch (TREE_CODE (arg)) 4319 { 4320 case NOP_EXPR: 4321 case CONVERT_EXPR: 4322 case FLOAT_EXPR: 4323 case FIX_TRUNC_EXPR: 4324 case FIX_FLOOR_EXPR: 4325 case FIX_ROUND_EXPR: 4326 case FIX_CEIL_EXPR: 4327 { 4328 tree incremented, modify, value, compound; 4329 if (! lvalue_p (arg) && pedantic) 4330 pedwarn ("cast to non-reference type used as lvalue"); 4331 arg = stabilize_reference (arg); 4332 if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) 4333 value = arg; 4334 else 4335 value = save_expr (arg); 4336 incremented = build2 (((code == PREINCREMENT_EXPR 4337 || code == POSTINCREMENT_EXPR) 4338 ? PLUS_EXPR : MINUS_EXPR), 4339 argtype, value, inc); 4340 4341 modify = build_modify_expr (arg, NOP_EXPR, incremented); 4342 compound = build2 (COMPOUND_EXPR, TREE_TYPE (arg), 4343 modify, value); 4344 4345 /* Eliminate warning about unused result of + or -. */ 4346 TREE_NO_WARNING (compound) = 1; 4347 return compound; 4348 } 4349 4350 default: 4351 break; 4352 } 4353 4354 /* Complain about anything else that is not a true lvalue. */ 4355 if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR 4356 || code == POSTINCREMENT_EXPR) 4357 ? lv_increment : lv_decrement))) 4358 return error_mark_node; 4359 4360 /* Forbid using -- on `bool'. */ 4361 if (same_type_p (declared_type, boolean_type_node)) 4362 { 4363 if (code == POSTDECREMENT_EXPR || code == PREDECREMENT_EXPR) 4364 { 4365 error ("invalid use of %<--%> on bool variable %qD", arg); 4366 return error_mark_node; 4367 } 4368 val = boolean_increment (code, arg); 4369 } 4370 else 4371 val = build2 (code, TREE_TYPE (arg), arg, inc); 4372 4373 TREE_SIDE_EFFECTS (val) = 1; 4374 return cp_convert (result_type, val); 4375 } 4376 4377 case ADDR_EXPR: 4378 /* Note that this operation never does default_conversion 4379 regardless of NOCONVERT. */ 4380 4381 argtype = lvalue_type (arg); 4382 4383 if (TREE_CODE (arg) == OFFSET_REF) 4384 goto offset_ref; 4385 4386 if (TREE_CODE (argtype) == REFERENCE_TYPE) 4387 { 4388 tree type = build_pointer_type (TREE_TYPE (argtype)); 4389 arg = build1 (CONVERT_EXPR, type, arg); 4390 return arg; 4391 } 4392 else if (pedantic && DECL_MAIN_P (arg)) 4393 /* ARM $3.4 */ 4394 pedwarn ("ISO C++ forbids taking address of function %<::main%>"); 4395 4396 /* Let &* cancel out to simplify resulting code. */ 4397 if (TREE_CODE (arg) == INDIRECT_REF) 4398 { 4399 /* We don't need to have `current_class_ptr' wrapped in a 4400 NON_LVALUE_EXPR node. */ 4401 if (arg == current_class_ref) 4402 return current_class_ptr; 4403 4404 arg = TREE_OPERAND (arg, 0); 4405 if (TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE) 4406 { 4407 tree type = build_pointer_type (TREE_TYPE (TREE_TYPE (arg))); 4408 arg = build1 (CONVERT_EXPR, type, arg); 4409 } 4410 else 4411 /* Don't let this be an lvalue. */ 4412 arg = rvalue (arg); 4413 return arg; 4414 } 4415 4416 /* Uninstantiated types are all functions. Taking the 4417 address of a function is a no-op, so just return the 4418 argument. */ 4419 4420 gcc_assert (TREE_CODE (arg) != IDENTIFIER_NODE 4421 || !IDENTIFIER_OPNAME_P (arg)); 4422 4423 if (TREE_CODE (arg) == COMPONENT_REF && type_unknown_p (arg) 4424 && !really_overloaded_fn (TREE_OPERAND (arg, 1))) 4425 { 4426 /* They're trying to take the address of a unique non-static 4427 member function. This is ill-formed (except in MS-land), 4428 but let's try to DTRT. 4429 Note: We only handle unique functions here because we don't 4430 want to complain if there's a static overload; non-unique 4431 cases will be handled by instantiate_type. But we need to 4432 handle this case here to allow casts on the resulting PMF. 4433 We could defer this in non-MS mode, but it's easier to give 4434 a useful error here. */ 4435 4436 /* Inside constant member functions, the `this' pointer 4437 contains an extra const qualifier. TYPE_MAIN_VARIANT 4438 is used here to remove this const from the diagnostics 4439 and the created OFFSET_REF. */ 4440 tree base = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (arg, 0))); 4441 tree fn = get_first_fn (TREE_OPERAND (arg, 1)); 4442 mark_used (fn); 4443 4444 if (! flag_ms_extensions) 4445 { 4446 tree name = DECL_NAME (fn); 4447 if (current_class_type 4448 && TREE_OPERAND (arg, 0) == current_class_ref) 4449 /* An expression like &memfn. */ 4450 pedwarn ("ISO C++ forbids taking the address of an unqualified" 4451 " or parenthesized non-static member function to form" 4452 " a pointer to member function. Say %<&%T::%D%>", 4453 base, name); 4454 else 4455 pedwarn ("ISO C++ forbids taking the address of a bound member" 4456 " function to form a pointer to member function." 4457 " Say %<&%T::%D%>", 4458 base, name); 4459 } 4460 arg = build_offset_ref (base, fn, /*address_p=*/true); 4461 } 4462 4463 offset_ref: 4464 if (type_unknown_p (arg)) 4465 return build1 (ADDR_EXPR, unknown_type_node, arg); 4466 4467 /* Handle complex lvalues (when permitted) 4468 by reduction to simpler cases. */ 4469 val = unary_complex_lvalue (code, arg); 4470 if (val != 0) 4471 return val; 4472 4473 switch (TREE_CODE (arg)) 4474 { 4475 case NOP_EXPR: 4476 case CONVERT_EXPR: 4477 case FLOAT_EXPR: 4478 case FIX_TRUNC_EXPR: 4479 case FIX_FLOOR_EXPR: 4480 case FIX_ROUND_EXPR: 4481 case FIX_CEIL_EXPR: 4482 if (! lvalue_p (arg) && pedantic) 4483 pedwarn ("ISO C++ forbids taking the address of a cast to a non-lvalue expression"); 4484 break; 4485 4486 case BASELINK: 4487 arg = BASELINK_FUNCTIONS (arg); 4488 /* Fall through. */ 4489 4490 case OVERLOAD: 4491 arg = OVL_CURRENT (arg); 4492 break; 4493 4494 case OFFSET_REF: 4495 /* Turn a reference to a non-static data member into a 4496 pointer-to-member. */ 4497 { 4498 tree type; 4499 tree t; 4500 4501 if (!PTRMEM_OK_P (arg)) 4502 return build_unary_op (code, arg, 0); 4503 4504 t = TREE_OPERAND (arg, 1); 4505 if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) 4506 { 4507 error ("cannot create pointer to reference member %qD", t); 4508 return error_mark_node; 4509 } 4510 4511 type = build_ptrmem_type (context_for_name_lookup (t), 4512 TREE_TYPE (t)); 4513 t = make_ptrmem_cst (type, TREE_OPERAND (arg, 1)); 4514 return t; 4515 } 4516 4517 default: 4518 break; 4519 } 4520 4521 /* Anything not already handled and not a true memory reference 4522 is an error. */ 4523 if (TREE_CODE (argtype) != FUNCTION_TYPE 4524 && TREE_CODE (argtype) != METHOD_TYPE 4525 && TREE_CODE (arg) != OFFSET_REF 4526 && !lvalue_or_else (arg, lv_addressof)) 4527 return error_mark_node; 4528 4529 if (argtype != error_mark_node) 4530 argtype = build_pointer_type (argtype); 4531 4532 /* In a template, we are processing a non-dependent expression 4533 so we can just form an ADDR_EXPR with the correct type. */ 4534 if (processing_template_decl) 4535 { 4536 val = build_address (arg); 4537 if (TREE_CODE (arg) == OFFSET_REF) 4538 PTRMEM_OK_P (val) = PTRMEM_OK_P (arg); 4539 return val; 4540 } 4541 4542 if (TREE_CODE (arg) != COMPONENT_REF) 4543 { 4544 val = build_address (arg); 4545 if (TREE_CODE (arg) == OFFSET_REF) 4546 PTRMEM_OK_P (val) = PTRMEM_OK_P (arg); 4547 } 4548 else if (TREE_CODE (TREE_OPERAND (arg, 1)) == BASELINK) 4549 { 4550 tree fn = BASELINK_FUNCTIONS (TREE_OPERAND (arg, 1)); 4551 4552 /* We can only get here with a single static member 4553 function. */ 4554 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL 4555 && DECL_STATIC_FUNCTION_P (fn)); 4556 mark_used (fn); 4557 val = build_address (fn); 4558 if (TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0))) 4559 /* Do not lose object's side effects. */ 4560 val = build2 (COMPOUND_EXPR, TREE_TYPE (val), 4561 TREE_OPERAND (arg, 0), val); 4562 } 4563 else if (DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1))) 4564 { 4565 error ("attempt to take address of bit-field structure member %qD", 4566 TREE_OPERAND (arg, 1)); 4567 return error_mark_node; 4568 } 4569 else 4570 { 4571 tree object = TREE_OPERAND (arg, 0); 4572 tree field = TREE_OPERAND (arg, 1); 4573 gcc_assert (same_type_ignoring_top_level_qualifiers_p 4574 (TREE_TYPE (object), decl_type_context (field))); 4575 val = build_address (arg); 4576 } 4577 4578 if (TREE_CODE (argtype) == POINTER_TYPE 4579 && TREE_CODE (TREE_TYPE (argtype)) == METHOD_TYPE) 4580 { 4581 build_ptrmemfunc_type (argtype); 4582 val = build_ptrmemfunc (argtype, val, 0, 4583 /*c_cast_p=*/false); 4584 } 4585 4586 return val; 4587 4588 default: 4589 break; 4590 } 4591 4592 if (!errstring) 4593 { 4594 if (argtype == 0) 4595 argtype = TREE_TYPE (arg); 4596 return fold_if_not_in_template (build1 (code, argtype, arg)); 4597 } 4598 4599 error ("%s", errstring); 4600 return error_mark_node; 4601} 4602 4603/* Apply unary lvalue-demanding operator CODE to the expression ARG 4604 for certain kinds of expressions which are not really lvalues 4605 but which we can accept as lvalues. 4606 4607 If ARG is not a kind of expression we can handle, return 4608 NULL_TREE. */ 4609 4610tree 4611unary_complex_lvalue (enum tree_code code, tree arg) 4612{ 4613 /* Inside a template, making these kinds of adjustments is 4614 pointless; we are only concerned with the type of the 4615 expression. */ 4616 if (processing_template_decl) 4617 return NULL_TREE; 4618 4619 /* Handle (a, b) used as an "lvalue". */ 4620 if (TREE_CODE (arg) == COMPOUND_EXPR) 4621 { 4622 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 1), 0); 4623 return build2 (COMPOUND_EXPR, TREE_TYPE (real_result), 4624 TREE_OPERAND (arg, 0), real_result); 4625 } 4626 4627 /* Handle (a ? b : c) used as an "lvalue". */ 4628 if (TREE_CODE (arg) == COND_EXPR 4629 || TREE_CODE (arg) == MIN_EXPR || TREE_CODE (arg) == MAX_EXPR) 4630 return rationalize_conditional_expr (code, arg); 4631 4632 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */ 4633 if (TREE_CODE (arg) == MODIFY_EXPR 4634 || TREE_CODE (arg) == PREINCREMENT_EXPR 4635 || TREE_CODE (arg) == PREDECREMENT_EXPR) 4636 { 4637 tree lvalue = TREE_OPERAND (arg, 0); 4638 if (TREE_SIDE_EFFECTS (lvalue)) 4639 { 4640 lvalue = stabilize_reference (lvalue); 4641 arg = build2 (TREE_CODE (arg), TREE_TYPE (arg), 4642 lvalue, TREE_OPERAND (arg, 1)); 4643 } 4644 return unary_complex_lvalue 4645 (code, build2 (COMPOUND_EXPR, TREE_TYPE (lvalue), arg, lvalue)); 4646 } 4647 4648 if (code != ADDR_EXPR) 4649 return NULL_TREE; 4650 4651 /* Handle (a = b) used as an "lvalue" for `&'. */ 4652 if (TREE_CODE (arg) == MODIFY_EXPR 4653 || TREE_CODE (arg) == INIT_EXPR) 4654 { 4655 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 0), 0); 4656 arg = build2 (COMPOUND_EXPR, TREE_TYPE (real_result), 4657 arg, real_result); 4658 TREE_NO_WARNING (arg) = 1; 4659 return arg; 4660 } 4661 4662 if (TREE_CODE (TREE_TYPE (arg)) == FUNCTION_TYPE 4663 || TREE_CODE (TREE_TYPE (arg)) == METHOD_TYPE 4664 || TREE_CODE (arg) == OFFSET_REF) 4665 return NULL_TREE; 4666 4667 /* We permit compiler to make function calls returning 4668 objects of aggregate type look like lvalues. */ 4669 { 4670 tree targ = arg; 4671 4672 if (TREE_CODE (targ) == SAVE_EXPR) 4673 targ = TREE_OPERAND (targ, 0); 4674 4675 if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (TREE_TYPE (targ))) 4676 { 4677 if (TREE_CODE (arg) == SAVE_EXPR) 4678 targ = arg; 4679 else 4680 targ = build_cplus_new (TREE_TYPE (arg), arg); 4681 return build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (arg)), targ); 4682 } 4683 4684 if (TREE_CODE (arg) == SAVE_EXPR && TREE_CODE (targ) == INDIRECT_REF) 4685 return build3 (SAVE_EXPR, build_pointer_type (TREE_TYPE (arg)), 4686 TREE_OPERAND (targ, 0), current_function_decl, NULL); 4687 } 4688 4689 /* Don't let anything else be handled specially. */ 4690 return NULL_TREE; 4691} 4692 4693/* Mark EXP saying that we need to be able to take the 4694 address of it; it should not be allocated in a register. 4695 Value is true if successful. 4696 4697 C++: we do not allow `current_class_ptr' to be addressable. */ 4698 4699bool 4700cxx_mark_addressable (tree exp) 4701{ 4702 tree x = exp; 4703 4704 while (1) 4705 switch (TREE_CODE (x)) 4706 { 4707 case ADDR_EXPR: 4708 case COMPONENT_REF: 4709 case ARRAY_REF: 4710 case REALPART_EXPR: 4711 case IMAGPART_EXPR: 4712 x = TREE_OPERAND (x, 0); 4713 break; 4714 4715 case PARM_DECL: 4716 if (x == current_class_ptr) 4717 { 4718 error ("cannot take the address of %<this%>, which is an rvalue expression"); 4719 TREE_ADDRESSABLE (x) = 1; /* so compiler doesn't die later. */ 4720 return true; 4721 } 4722 /* Fall through. */ 4723 4724 case VAR_DECL: 4725 /* Caller should not be trying to mark initialized 4726 constant fields addressable. */ 4727 gcc_assert (DECL_LANG_SPECIFIC (x) == 0 4728 || DECL_IN_AGGR_P (x) == 0 4729 || TREE_STATIC (x) 4730 || DECL_EXTERNAL (x)); 4731 /* Fall through. */ 4732 4733 case CONST_DECL: 4734 case RESULT_DECL: 4735 if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x) 4736 && !DECL_ARTIFICIAL (x)) 4737 { 4738 if (TREE_CODE (x) == VAR_DECL && DECL_HARD_REGISTER (x)) 4739 { 4740 error 4741 ("address of explicit register variable %qD requested", x); 4742 return false; 4743 } 4744 else if (extra_warnings) 4745 warning 4746 (OPT_Wextra, "address requested for %qD, which is declared %<register%>", x); 4747 } 4748 TREE_ADDRESSABLE (x) = 1; 4749 return true; 4750 4751 case FUNCTION_DECL: 4752 TREE_ADDRESSABLE (x) = 1; 4753 return true; 4754 4755 case CONSTRUCTOR: 4756 TREE_ADDRESSABLE (x) = 1; 4757 return true; 4758 4759 case TARGET_EXPR: 4760 TREE_ADDRESSABLE (x) = 1; 4761 cxx_mark_addressable (TREE_OPERAND (x, 0)); 4762 return true; 4763 4764 default: 4765 return true; 4766 } 4767} 4768 4769/* Build and return a conditional expression IFEXP ? OP1 : OP2. */ 4770 4771tree 4772build_x_conditional_expr (tree ifexp, tree op1, tree op2) 4773{ 4774 tree orig_ifexp = ifexp; 4775 tree orig_op1 = op1; 4776 tree orig_op2 = op2; 4777 tree expr; 4778 4779 if (processing_template_decl) 4780 { 4781 /* The standard says that the expression is type-dependent if 4782 IFEXP is type-dependent, even though the eventual type of the 4783 expression doesn't dependent on IFEXP. */ 4784 if (type_dependent_expression_p (ifexp) 4785 /* As a GNU extension, the middle operand may be omitted. */ 4786 || (op1 && type_dependent_expression_p (op1)) 4787 || type_dependent_expression_p (op2)) 4788 return build_min_nt (COND_EXPR, ifexp, op1, op2); 4789 ifexp = build_non_dependent_expr (ifexp); 4790 if (op1) 4791 op1 = build_non_dependent_expr (op1); 4792 op2 = build_non_dependent_expr (op2); 4793 } 4794 4795 expr = build_conditional_expr (ifexp, op1, op2); 4796 if (processing_template_decl && expr != error_mark_node) 4797 return build_min_non_dep (COND_EXPR, expr, 4798 orig_ifexp, orig_op1, orig_op2); 4799 return expr; 4800} 4801 4802/* Given a list of expressions, return a compound expression 4803 that performs them all and returns the value of the last of them. */ 4804 4805tree build_x_compound_expr_from_list (tree list, const char *msg) 4806{ 4807 tree expr = TREE_VALUE (list); 4808 4809 if (TREE_CHAIN (list)) 4810 { 4811 if (msg) 4812 pedwarn ("%s expression list treated as compound expression", msg); 4813 4814 for (list = TREE_CHAIN (list); list; list = TREE_CHAIN (list)) 4815 expr = build_x_compound_expr (expr, TREE_VALUE (list)); 4816 } 4817 4818 return expr; 4819} 4820 4821/* Handle overloading of the ',' operator when needed. */ 4822 4823tree 4824build_x_compound_expr (tree op1, tree op2) 4825{ 4826 tree result; 4827 tree orig_op1 = op1; 4828 tree orig_op2 = op2; 4829 4830 if (processing_template_decl) 4831 { 4832 if (type_dependent_expression_p (op1) 4833 || type_dependent_expression_p (op2)) 4834 return build_min_nt (COMPOUND_EXPR, op1, op2); 4835 op1 = build_non_dependent_expr (op1); 4836 op2 = build_non_dependent_expr (op2); 4837 } 4838 4839 result = build_new_op (COMPOUND_EXPR, LOOKUP_NORMAL, op1, op2, NULL_TREE, 4840 /*overloaded_p=*/NULL); 4841 if (!result) 4842 result = build_compound_expr (op1, op2); 4843 4844 if (processing_template_decl && result != error_mark_node) 4845 return build_min_non_dep (COMPOUND_EXPR, result, orig_op1, orig_op2); 4846 4847 return result; 4848} 4849 4850/* Build a compound expression. */ 4851 4852tree 4853build_compound_expr (tree lhs, tree rhs) 4854{ 4855 lhs = convert_to_void (lhs, "left-hand operand of comma"); 4856 4857 if (lhs == error_mark_node || rhs == error_mark_node) 4858 return error_mark_node; 4859 4860 if (TREE_CODE (rhs) == TARGET_EXPR) 4861 { 4862 /* If the rhs is a TARGET_EXPR, then build the compound 4863 expression inside the target_expr's initializer. This 4864 helps the compiler to eliminate unnecessary temporaries. */ 4865 tree init = TREE_OPERAND (rhs, 1); 4866 4867 init = build2 (COMPOUND_EXPR, TREE_TYPE (init), lhs, init); 4868 TREE_OPERAND (rhs, 1) = init; 4869 4870 return rhs; 4871 } 4872 4873 return build2 (COMPOUND_EXPR, TREE_TYPE (rhs), lhs, rhs); 4874} 4875 4876/* Issue a diagnostic message if casting from SRC_TYPE to DEST_TYPE 4877 casts away constness. DIAG_FN gives the function to call if we 4878 need to issue a diagnostic; if it is NULL, no diagnostic will be 4879 issued. DESCRIPTION explains what operation is taking place. */ 4880 4881static void 4882check_for_casting_away_constness (tree src_type, tree dest_type, 4883 void (*diag_fn)(const char *, ...) ATTRIBUTE_GCC_CXXDIAG(1,2), 4884 const char *description) 4885{ 4886 if (diag_fn && casts_away_constness (src_type, dest_type)) 4887 diag_fn ("%s from type %qT to type %qT casts away constness", 4888 description, src_type, dest_type); 4889} 4890 4891/* Convert EXPR (an expression with pointer-to-member type) to TYPE 4892 (another pointer-to-member type in the same hierarchy) and return 4893 the converted expression. If ALLOW_INVERSE_P is permitted, a 4894 pointer-to-derived may be converted to pointer-to-base; otherwise, 4895 only the other direction is permitted. If C_CAST_P is true, this 4896 conversion is taking place as part of a C-style cast. */ 4897 4898tree 4899convert_ptrmem (tree type, tree expr, bool allow_inverse_p, 4900 bool c_cast_p) 4901{ 4902 if (TYPE_PTRMEM_P (type)) 4903 { 4904 tree delta; 4905 4906 if (TREE_CODE (expr) == PTRMEM_CST) 4907 expr = cplus_expand_constant (expr); 4908 delta = get_delta_difference (TYPE_PTRMEM_CLASS_TYPE (TREE_TYPE (expr)), 4909 TYPE_PTRMEM_CLASS_TYPE (type), 4910 allow_inverse_p, 4911 c_cast_p); 4912 if (!integer_zerop (delta)) 4913 expr = cp_build_binary_op (PLUS_EXPR, 4914 build_nop (ptrdiff_type_node, expr), 4915 delta); 4916 return build_nop (type, expr); 4917 } 4918 else 4919 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 4920 allow_inverse_p, c_cast_p); 4921} 4922 4923/* If EXPR is an INTEGER_CST and ORIG is an arithmetic constant, return 4924 a version of EXPR that has TREE_OVERFLOW and/or TREE_CONSTANT_OVERFLOW 4925 set iff they are set in ORIG. Otherwise, return EXPR unchanged. */ 4926 4927static tree 4928ignore_overflows (tree expr, tree orig) 4929{ 4930 if (TREE_CODE (expr) == INTEGER_CST 4931 && CONSTANT_CLASS_P (orig) 4932 && TREE_CODE (orig) != STRING_CST 4933 && (TREE_OVERFLOW (expr) != TREE_OVERFLOW (orig) 4934 || TREE_CONSTANT_OVERFLOW (expr) 4935 != TREE_CONSTANT_OVERFLOW (orig))) 4936 { 4937 if (!TREE_OVERFLOW (orig) && !TREE_CONSTANT_OVERFLOW (orig)) 4938 /* Ensure constant sharing. */ 4939 expr = build_int_cst_wide (TREE_TYPE (expr), 4940 TREE_INT_CST_LOW (expr), 4941 TREE_INT_CST_HIGH (expr)); 4942 else 4943 { 4944 /* Avoid clobbering a shared constant. */ 4945 expr = copy_node (expr); 4946 TREE_OVERFLOW (expr) = TREE_OVERFLOW (orig); 4947 TREE_CONSTANT_OVERFLOW (expr) 4948 = TREE_CONSTANT_OVERFLOW (orig); 4949 } 4950 } 4951 return expr; 4952} 4953 4954/* Perform a static_cast from EXPR to TYPE. When C_CAST_P is true, 4955 this static_cast is being attempted as one of the possible casts 4956 allowed by a C-style cast. (In that case, accessibility of base 4957 classes is not considered, and it is OK to cast away 4958 constness.) Return the result of the cast. *VALID_P is set to 4959 indicate whether or not the cast was valid. */ 4960 4961static tree 4962build_static_cast_1 (tree type, tree expr, bool c_cast_p, 4963 bool *valid_p) 4964{ 4965 tree intype; 4966 tree result; 4967 tree orig; 4968 void (*diag_fn)(const char*, ...) ATTRIBUTE_GCC_CXXDIAG(1,2); 4969 const char *desc; 4970 4971 /* Assume the cast is valid. */ 4972 *valid_p = true; 4973 4974 intype = TREE_TYPE (expr); 4975 4976 /* Save casted types in the function's used types hash table. */ 4977 used_types_insert (type); 4978 4979 /* Determine what to do when casting away constness. */ 4980 if (c_cast_p) 4981 { 4982 /* C-style casts are allowed to cast away constness. With 4983 WARN_CAST_QUAL, we still want to issue a warning. */ 4984 diag_fn = warn_cast_qual ? warning0 : NULL; 4985 desc = "cast"; 4986 } 4987 else 4988 { 4989 /* A static_cast may not cast away constness. */ 4990 diag_fn = error; 4991 desc = "static_cast"; 4992 } 4993 4994 /* [expr.static.cast] 4995 4996 An lvalue of type "cv1 B", where B is a class type, can be cast 4997 to type "reference to cv2 D", where D is a class derived (clause 4998 _class.derived_) from B, if a valid standard conversion from 4999 "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the 5000 same cv-qualification as, or greater cv-qualification than, cv1, 5001 and B is not a virtual base class of D. */ 5002 /* We check this case before checking the validity of "TYPE t = 5003 EXPR;" below because for this case: 5004 5005 struct B {}; 5006 struct D : public B { D(const B&); }; 5007 extern B& b; 5008 void f() { static_cast<const D&>(b); } 5009 5010 we want to avoid constructing a new D. The standard is not 5011 completely clear about this issue, but our interpretation is 5012 consistent with other compilers. */ 5013 if (TREE_CODE (type) == REFERENCE_TYPE 5014 && CLASS_TYPE_P (TREE_TYPE (type)) 5015 && CLASS_TYPE_P (intype) 5016 && real_lvalue_p (expr) 5017 && DERIVED_FROM_P (intype, TREE_TYPE (type)) 5018 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT (intype)), 5019 build_pointer_type (TYPE_MAIN_VARIANT 5020 (TREE_TYPE (type)))) 5021 && (c_cast_p 5022 || at_least_as_qualified_p (TREE_TYPE (type), intype))) 5023 { 5024 tree base; 5025 5026 /* There is a standard conversion from "D*" to "B*" even if "B" 5027 is ambiguous or inaccessible. If this is really a 5028 static_cast, then we check both for inaccessibility and 5029 ambiguity. However, if this is a static_cast being performed 5030 because the user wrote a C-style cast, then accessibility is 5031 not considered. */ 5032 base = lookup_base (TREE_TYPE (type), intype, 5033 c_cast_p ? ba_unique : ba_check, 5034 NULL); 5035 5036 /* Convert from "B*" to "D*". This function will check that "B" 5037 is not a virtual base of "D". */ 5038 expr = build_base_path (MINUS_EXPR, build_address (expr), 5039 base, /*nonnull=*/false); 5040 /* Convert the pointer to a reference -- but then remember that 5041 there are no expressions with reference type in C++. */ 5042 return convert_from_reference (build_nop (type, expr)); 5043 } 5044 5045 orig = expr; 5046 5047 /* [expr.static.cast] 5048 5049 An expression e can be explicitly converted to a type T using a 5050 static_cast of the form static_cast<T>(e) if the declaration T 5051 t(e);" is well-formed, for some invented temporary variable 5052 t. */ 5053 result = perform_direct_initialization_if_possible (type, expr, 5054 c_cast_p); 5055 if (result) 5056 { 5057 result = convert_from_reference (result); 5058 5059 /* Ignore any integer overflow caused by the cast. */ 5060 result = ignore_overflows (result, orig); 5061 5062 /* [expr.static.cast] 5063 5064 If T is a reference type, the result is an lvalue; otherwise, 5065 the result is an rvalue. */ 5066 if (TREE_CODE (type) != REFERENCE_TYPE) 5067 result = rvalue (result); 5068 return result; 5069 } 5070 5071 /* [expr.static.cast] 5072 5073 Any expression can be explicitly converted to type cv void. */ 5074 if (TREE_CODE (type) == VOID_TYPE) 5075 return convert_to_void (expr, /*implicit=*/NULL); 5076 5077 /* [expr.static.cast] 5078 5079 The inverse of any standard conversion sequence (clause _conv_), 5080 other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer 5081 (_conv.array_), function-to-pointer (_conv.func_), and boolean 5082 (_conv.bool_) conversions, can be performed explicitly using 5083 static_cast subject to the restriction that the explicit 5084 conversion does not cast away constness (_expr.const.cast_), and 5085 the following additional rules for specific cases: */ 5086 /* For reference, the conversions not excluded are: integral 5087 promotions, floating point promotion, integral conversions, 5088 floating point conversions, floating-integral conversions, 5089 pointer conversions, and pointer to member conversions. */ 5090 /* DR 128 5091 5092 A value of integral _or enumeration_ type can be explicitly 5093 converted to an enumeration type. */ 5094 /* The effect of all that is that any conversion between any two 5095 types which are integral, floating, or enumeration types can be 5096 performed. */ 5097 if ((INTEGRAL_TYPE_P (type) || SCALAR_FLOAT_TYPE_P (type)) 5098 && (INTEGRAL_TYPE_P (intype) || SCALAR_FLOAT_TYPE_P (intype))) 5099 { 5100 expr = ocp_convert (type, expr, CONV_C_CAST, LOOKUP_NORMAL); 5101 5102 /* Ignore any integer overflow caused by the cast. */ 5103 expr = ignore_overflows (expr, orig); 5104 return expr; 5105 } 5106 5107 if (TYPE_PTR_P (type) && TYPE_PTR_P (intype) 5108 && CLASS_TYPE_P (TREE_TYPE (type)) 5109 && CLASS_TYPE_P (TREE_TYPE (intype)) 5110 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT 5111 (TREE_TYPE (intype))), 5112 build_pointer_type (TYPE_MAIN_VARIANT 5113 (TREE_TYPE (type))))) 5114 { 5115 tree base; 5116 5117 if (!c_cast_p) 5118 check_for_casting_away_constness (intype, type, diag_fn, desc); 5119 base = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), 5120 c_cast_p ? ba_unique : ba_check, 5121 NULL); 5122 return build_base_path (MINUS_EXPR, expr, base, /*nonnull=*/false); 5123 } 5124 5125 if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) 5126 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) 5127 { 5128 tree c1; 5129 tree c2; 5130 tree t1; 5131 tree t2; 5132 5133 c1 = TYPE_PTRMEM_CLASS_TYPE (intype); 5134 c2 = TYPE_PTRMEM_CLASS_TYPE (type); 5135 5136 if (TYPE_PTRMEM_P (type)) 5137 { 5138 t1 = (build_ptrmem_type 5139 (c1, 5140 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (intype)))); 5141 t2 = (build_ptrmem_type 5142 (c2, 5143 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (type)))); 5144 } 5145 else 5146 { 5147 t1 = intype; 5148 t2 = type; 5149 } 5150 if (can_convert (t1, t2)) 5151 { 5152 if (!c_cast_p) 5153 check_for_casting_away_constness (intype, type, diag_fn, 5154 desc); 5155 return convert_ptrmem (type, expr, /*allow_inverse_p=*/1, 5156 c_cast_p); 5157 } 5158 } 5159 5160 /* [expr.static.cast] 5161 5162 An rvalue of type "pointer to cv void" can be explicitly 5163 converted to a pointer to object type. A value of type pointer 5164 to object converted to "pointer to cv void" and back to the 5165 original pointer type will have its original value. */ 5166 if (TREE_CODE (intype) == POINTER_TYPE 5167 && VOID_TYPE_P (TREE_TYPE (intype)) 5168 && TYPE_PTROB_P (type)) 5169 { 5170 if (!c_cast_p) 5171 check_for_casting_away_constness (intype, type, diag_fn, desc); 5172 return build_nop (type, expr); 5173 } 5174 5175 *valid_p = false; 5176 return error_mark_node; 5177} 5178 5179/* Return an expression representing static_cast<TYPE>(EXPR). */ 5180 5181tree 5182build_static_cast (tree type, tree expr) 5183{ 5184 tree result; 5185 bool valid_p; 5186 5187 if (type == error_mark_node || expr == error_mark_node) 5188 return error_mark_node; 5189 5190 if (processing_template_decl) 5191 { 5192 expr = build_min (STATIC_CAST_EXPR, type, expr); 5193 /* We don't know if it will or will not have side effects. */ 5194 TREE_SIDE_EFFECTS (expr) = 1; 5195 return convert_from_reference (expr); 5196 } 5197 5198 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 5199 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 5200 if (TREE_CODE (type) != REFERENCE_TYPE 5201 && TREE_CODE (expr) == NOP_EXPR 5202 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 5203 expr = TREE_OPERAND (expr, 0); 5204 5205 result = build_static_cast_1 (type, expr, /*c_cast_p=*/false, &valid_p); 5206 if (valid_p) 5207 return result; 5208 5209 error ("invalid static_cast from type %qT to type %qT", 5210 TREE_TYPE (expr), type); 5211 return error_mark_node; 5212} 5213 5214/* EXPR is an expression with member function or pointer-to-member 5215 function type. TYPE is a pointer type. Converting EXPR to TYPE is 5216 not permitted by ISO C++, but we accept it in some modes. If we 5217 are not in one of those modes, issue a diagnostic. Return the 5218 converted expression. */ 5219 5220tree 5221convert_member_func_to_ptr (tree type, tree expr) 5222{ 5223 tree intype; 5224 tree decl; 5225 5226 intype = TREE_TYPE (expr); 5227 gcc_assert (TYPE_PTRMEMFUNC_P (intype) 5228 || TREE_CODE (intype) == METHOD_TYPE); 5229 5230 if (pedantic || warn_pmf2ptr) 5231 pedwarn ("converting from %qT to %qT", intype, type); 5232 5233 if (TREE_CODE (intype) == METHOD_TYPE) 5234 expr = build_addr_func (expr); 5235 else if (TREE_CODE (expr) == PTRMEM_CST) 5236 expr = build_address (PTRMEM_CST_MEMBER (expr)); 5237 else 5238 { 5239 decl = maybe_dummy_object (TYPE_PTRMEM_CLASS_TYPE (intype), 0); 5240 decl = build_address (decl); 5241 expr = get_member_function_from_ptrfunc (&decl, expr); 5242 } 5243 5244 return build_nop (type, expr); 5245} 5246 5247/* Return a representation for a reinterpret_cast from EXPR to TYPE. 5248 If C_CAST_P is true, this reinterpret cast is being done as part of 5249 a C-style cast. If VALID_P is non-NULL, *VALID_P is set to 5250 indicate whether or not reinterpret_cast was valid. */ 5251 5252static tree 5253build_reinterpret_cast_1 (tree type, tree expr, bool c_cast_p, 5254 bool *valid_p) 5255{ 5256 tree intype; 5257 5258 /* Assume the cast is invalid. */ 5259 if (valid_p) 5260 *valid_p = true; 5261 5262 if (type == error_mark_node || error_operand_p (expr)) 5263 return error_mark_node; 5264 5265 intype = TREE_TYPE (expr); 5266 5267 /* Save casted types in the function's used types hash table. */ 5268 used_types_insert (type); 5269 5270 /* [expr.reinterpret.cast] 5271 An lvalue expression of type T1 can be cast to the type 5272 "reference to T2" if an expression of type "pointer to T1" can be 5273 explicitly converted to the type "pointer to T2" using a 5274 reinterpret_cast. */ 5275 if (TREE_CODE (type) == REFERENCE_TYPE) 5276 { 5277 if (! real_lvalue_p (expr)) 5278 { 5279 error ("invalid cast of an rvalue expression of type " 5280 "%qT to type %qT", 5281 intype, type); 5282 return error_mark_node; 5283 } 5284 5285 /* Warn about a reinterpret_cast from "A*" to "B&" if "A" and 5286 "B" are related class types; the reinterpret_cast does not 5287 adjust the pointer. */ 5288 if (TYPE_PTR_P (intype) 5289 && (comptypes (TREE_TYPE (intype), TREE_TYPE (type), 5290 COMPARE_BASE | COMPARE_DERIVED))) 5291 warning (0, "casting %qT to %qT does not dereference pointer", 5292 intype, type); 5293 5294 expr = build_unary_op (ADDR_EXPR, expr, 0); 5295 if (expr != error_mark_node) 5296 expr = build_reinterpret_cast_1 5297 (build_pointer_type (TREE_TYPE (type)), expr, c_cast_p, 5298 valid_p); 5299 if (expr != error_mark_node) 5300 expr = build_indirect_ref (expr, 0); 5301 return expr; 5302 } 5303 5304 /* As a G++ extension, we consider conversions from member 5305 functions, and pointers to member functions to 5306 pointer-to-function and pointer-to-void types. If 5307 -Wno-pmf-conversions has not been specified, 5308 convert_member_func_to_ptr will issue an error message. */ 5309 if ((TYPE_PTRMEMFUNC_P (intype) 5310 || TREE_CODE (intype) == METHOD_TYPE) 5311 && TYPE_PTR_P (type) 5312 && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE 5313 || VOID_TYPE_P (TREE_TYPE (type)))) 5314 return convert_member_func_to_ptr (type, expr); 5315 5316 /* If the cast is not to a reference type, the lvalue-to-rvalue, 5317 array-to-pointer, and function-to-pointer conversions are 5318 performed. */ 5319 expr = decay_conversion (expr); 5320 5321 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 5322 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 5323 if (TREE_CODE (expr) == NOP_EXPR 5324 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 5325 expr = TREE_OPERAND (expr, 0); 5326 5327 if (error_operand_p (expr)) 5328 return error_mark_node; 5329 5330 intype = TREE_TYPE (expr); 5331 5332 /* [expr.reinterpret.cast] 5333 A pointer can be converted to any integral type large enough to 5334 hold it. */ 5335 if (CP_INTEGRAL_TYPE_P (type) && TYPE_PTR_P (intype)) 5336 { 5337 if (TYPE_PRECISION (type) < TYPE_PRECISION (intype)) 5338 pedwarn ("cast from %qT to %qT loses precision", 5339 intype, type); 5340 } 5341 /* [expr.reinterpret.cast] 5342 A value of integral or enumeration type can be explicitly 5343 converted to a pointer. */ 5344 else if (TYPE_PTR_P (type) && INTEGRAL_OR_ENUMERATION_TYPE_P (intype)) 5345 /* OK */ 5346 ; 5347 /* APPLE LOCAL begin blocks 6040305 (ck) */ 5348 else if (TREE_CODE (type) == INTEGER_TYPE && TREE_CODE (intype) == BLOCK_POINTER_TYPE) 5349 { 5350 if (TYPE_PRECISION (type) < TYPE_PRECISION (intype)) 5351 pedwarn ("cast from %qT to %qT loses precision", 5352 intype, type); 5353 } 5354 else if (TREE_CODE (type) == BLOCK_POINTER_TYPE && TREE_CODE (intype) == INTEGER_TYPE) 5355 /* OK */ 5356 ; 5357 else if (TREE_CODE (type) == BLOCK_POINTER_TYPE && TREE_CODE (intype) == BLOCK_POINTER_TYPE) 5358 /* OK */ 5359 ; 5360 else if (TREE_CODE (intype) == BLOCK_POINTER_TYPE 5361 && (objc_is_id (type) 5362 || (TREE_CODE (type) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (type))))) 5363 /* OK */ 5364 ; 5365 else if (TREE_CODE (type) == BLOCK_POINTER_TYPE 5366 && TREE_CODE (intype) == POINTER_TYPE 5367 && (objc_is_id (intype) || VOID_TYPE_P (TREE_TYPE (intype)))) 5368 /* OK */ 5369 ; 5370 /* APPLE LOCAL end blocks 6040305 (ck) */ 5371 else if ((TYPE_PTRFN_P (type) && TYPE_PTRFN_P (intype)) 5372 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) 5373 return fold_if_not_in_template (build_nop (type, expr)); 5374 else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) 5375 || (TYPE_PTROBV_P (type) && TYPE_PTROBV_P (intype))) 5376 { 5377 tree sexpr = expr; 5378 5379 if (!c_cast_p) 5380 check_for_casting_away_constness (intype, type, error, 5381 "reinterpret_cast"); 5382 /* Warn about possible alignment problems. */ 5383 if (STRICT_ALIGNMENT && warn_cast_align 5384 && !VOID_TYPE_P (type) 5385 && TREE_CODE (TREE_TYPE (intype)) != FUNCTION_TYPE 5386 && COMPLETE_TYPE_P (TREE_TYPE (type)) 5387 && COMPLETE_TYPE_P (TREE_TYPE (intype)) 5388 && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (intype))) 5389 warning (0, "cast from %qT to %qT increases required alignment of " 5390 "target type", 5391 intype, type); 5392 5393 /* We need to strip nops here, because the frontend likes to 5394 create (int *)&a for array-to-pointer decay, instead of &a[0]. */ 5395 STRIP_NOPS (sexpr); 5396 if (warn_strict_aliasing <= 2) 5397 strict_aliasing_warning (intype, type, sexpr); 5398 5399 return fold_if_not_in_template (build_nop (type, expr)); 5400 } 5401 else if ((TYPE_PTRFN_P (type) && TYPE_PTROBV_P (intype)) 5402 || (TYPE_PTRFN_P (intype) && TYPE_PTROBV_P (type))) 5403 { 5404 if (pedantic) 5405 /* Only issue a warning, as we have always supported this 5406 where possible, and it is necessary in some cases. DR 195 5407 addresses this issue, but as of 2004/10/26 is still in 5408 drafting. */ 5409 warning (0, "ISO C++ forbids casting between pointer-to-function and pointer-to-object"); 5410 return fold_if_not_in_template (build_nop (type, expr)); 5411 } 5412 else if (TREE_CODE (type) == VECTOR_TYPE) 5413 return fold_if_not_in_template (convert_to_vector (type, expr)); 5414 else if (TREE_CODE (intype) == VECTOR_TYPE && INTEGRAL_TYPE_P (type)) 5415 return fold_if_not_in_template (convert_to_integer (type, expr)); 5416 else 5417 { 5418 if (valid_p) 5419 *valid_p = false; 5420 error ("invalid cast from type %qT to type %qT", intype, type); 5421 return error_mark_node; 5422 } 5423 5424 /* APPLE LOCAL begin don't sign-extend pointers cast to integers */ 5425 if (TREE_CODE (type) == INTEGER_TYPE 5426 && TREE_CODE (intype) == POINTER_TYPE 5427 && TYPE_PRECISION (type) > TYPE_PRECISION (intype) 5428 && TYPE_UNSIGNED (type)) 5429 expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 1), expr); 5430 /* APPLE LOCAL end don't sign-extend pointers cast to integers */ 5431 5432 return cp_convert (type, expr); 5433} 5434 5435tree 5436build_reinterpret_cast (tree type, tree expr) 5437{ 5438 if (type == error_mark_node || expr == error_mark_node) 5439 return error_mark_node; 5440 5441 if (processing_template_decl) 5442 { 5443 tree t = build_min (REINTERPRET_CAST_EXPR, type, expr); 5444 5445 if (!TREE_SIDE_EFFECTS (t) 5446 && type_dependent_expression_p (expr)) 5447 /* There might turn out to be side effects inside expr. */ 5448 TREE_SIDE_EFFECTS (t) = 1; 5449 return convert_from_reference (t); 5450 } 5451 5452 return build_reinterpret_cast_1 (type, expr, /*c_cast_p=*/false, 5453 /*valid_p=*/NULL); 5454} 5455 5456/* Perform a const_cast from EXPR to TYPE. If the cast is valid, 5457 return an appropriate expression. Otherwise, return 5458 error_mark_node. If the cast is not valid, and COMPLAIN is true, 5459 then a diagnostic will be issued. If VALID_P is non-NULL, we are 5460 performing a C-style cast, its value upon return will indicate 5461 whether or not the conversion succeeded. */ 5462 5463static tree 5464build_const_cast_1 (tree dst_type, tree expr, bool complain, 5465 bool *valid_p) 5466{ 5467 tree src_type; 5468 tree reference_type; 5469 5470 /* Callers are responsible for handling error_mark_node as a 5471 destination type. */ 5472 gcc_assert (dst_type != error_mark_node); 5473 /* In a template, callers should be building syntactic 5474 representations of casts, not using this machinery. */ 5475 gcc_assert (!processing_template_decl); 5476 5477 /* Assume the conversion is invalid. */ 5478 if (valid_p) 5479 *valid_p = false; 5480 5481 if (!POINTER_TYPE_P (dst_type) && !TYPE_PTRMEM_P (dst_type)) 5482 { 5483 if (complain) 5484 error ("invalid use of const_cast with type %qT, " 5485 "which is not a pointer, " 5486 "reference, nor a pointer-to-data-member type", dst_type); 5487 return error_mark_node; 5488 } 5489 5490 if (TREE_CODE (TREE_TYPE (dst_type)) == FUNCTION_TYPE) 5491 { 5492 if (complain) 5493 error ("invalid use of const_cast with type %qT, which is a pointer " 5494 "or reference to a function type", dst_type); 5495 return error_mark_node; 5496 } 5497 5498 /* Save casted types in the function's used types hash table. */ 5499 used_types_insert (dst_type); 5500 5501 src_type = TREE_TYPE (expr); 5502 /* Expressions do not really have reference types. */ 5503 if (TREE_CODE (src_type) == REFERENCE_TYPE) 5504 src_type = TREE_TYPE (src_type); 5505 5506 /* [expr.const.cast] 5507 5508 An lvalue of type T1 can be explicitly converted to an lvalue of 5509 type T2 using the cast const_cast<T2&> (where T1 and T2 are object 5510 types) if a pointer to T1 can be explicitly converted to the type 5511 pointer to T2 using a const_cast. */ 5512 if (TREE_CODE (dst_type) == REFERENCE_TYPE) 5513 { 5514 reference_type = dst_type; 5515 if (! real_lvalue_p (expr)) 5516 { 5517 if (complain) 5518 error ("invalid const_cast of an rvalue of type %qT to type %qT", 5519 src_type, dst_type); 5520 return error_mark_node; 5521 } 5522 dst_type = build_pointer_type (TREE_TYPE (dst_type)); 5523 src_type = build_pointer_type (src_type); 5524 } 5525 else 5526 { 5527 reference_type = NULL_TREE; 5528 /* If the destination type is not a reference type, the 5529 lvalue-to-rvalue, array-to-pointer, and function-to-pointer 5530 conversions are performed. */ 5531 src_type = type_decays_to (src_type); 5532 if (src_type == error_mark_node) 5533 return error_mark_node; 5534 } 5535 5536 if ((TYPE_PTR_P (src_type) || TYPE_PTRMEM_P (src_type)) 5537 && comp_ptr_ttypes_const (dst_type, src_type)) 5538 { 5539 if (valid_p) 5540 { 5541 *valid_p = true; 5542 /* This cast is actually a C-style cast. Issue a warning if 5543 the user is making a potentially unsafe cast. */ 5544 if (warn_cast_qual) 5545 check_for_casting_away_constness (src_type, dst_type, 5546 warning0, 5547 "cast"); 5548 } 5549 if (reference_type) 5550 { 5551 expr = build_unary_op (ADDR_EXPR, expr, 0); 5552 expr = build_nop (reference_type, expr); 5553 return convert_from_reference (expr); 5554 } 5555 else 5556 { 5557 expr = decay_conversion (expr); 5558 /* build_c_cast puts on a NOP_EXPR to make the result not an 5559 lvalue. Strip such NOP_EXPRs if VALUE is being used in 5560 non-lvalue context. */ 5561 if (TREE_CODE (expr) == NOP_EXPR 5562 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 5563 expr = TREE_OPERAND (expr, 0); 5564 return build_nop (dst_type, expr); 5565 } 5566 } 5567 5568 if (complain) 5569 error ("invalid const_cast from type %qT to type %qT", 5570 src_type, dst_type); 5571 return error_mark_node; 5572} 5573 5574tree 5575build_const_cast (tree type, tree expr) 5576{ 5577 if (type == error_mark_node || error_operand_p (expr)) 5578 return error_mark_node; 5579 5580 if (processing_template_decl) 5581 { 5582 tree t = build_min (CONST_CAST_EXPR, type, expr); 5583 5584 if (!TREE_SIDE_EFFECTS (t) 5585 && type_dependent_expression_p (expr)) 5586 /* There might turn out to be side effects inside expr. */ 5587 TREE_SIDE_EFFECTS (t) = 1; 5588 return convert_from_reference (t); 5589 } 5590 5591 return build_const_cast_1 (type, expr, /*complain=*/true, 5592 /*valid_p=*/NULL); 5593} 5594 5595/* Build an expression representing an explicit C-style cast to type 5596 TYPE of expression EXPR. */ 5597 5598tree 5599build_c_cast (tree type, tree expr) 5600{ 5601 tree value = expr; 5602 tree result; 5603 bool valid_p; 5604 5605 if (type == error_mark_node || error_operand_p (expr)) 5606 return error_mark_node; 5607 5608 if (processing_template_decl) 5609 { 5610 tree t = build_min (CAST_EXPR, type, 5611 tree_cons (NULL_TREE, value, NULL_TREE)); 5612 /* We don't know if it will or will not have side effects. */ 5613 TREE_SIDE_EFFECTS (t) = 1; 5614 return convert_from_reference (t); 5615 } 5616 5617 /* Casts to a (pointer to a) specific ObjC class (or 'id' or 5618 'Class') should always be retained, because this information aids 5619 in method lookup. */ 5620 if (objc_is_object_ptr (type) 5621 && objc_is_object_ptr (TREE_TYPE (expr))) 5622 return build_nop (type, expr); 5623 5624 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 5625 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 5626 if (TREE_CODE (type) != REFERENCE_TYPE 5627 && TREE_CODE (value) == NOP_EXPR 5628 && TREE_TYPE (value) == TREE_TYPE (TREE_OPERAND (value, 0))) 5629 value = TREE_OPERAND (value, 0); 5630 5631 if (TREE_CODE (type) == ARRAY_TYPE) 5632 { 5633 /* Allow casting from T1* to T2[] because Cfront allows it. 5634 NIHCL uses it. It is not valid ISO C++ however. */ 5635 if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) 5636 { 5637 pedwarn ("ISO C++ forbids casting to an array type %qT", type); 5638 type = build_pointer_type (TREE_TYPE (type)); 5639 } 5640 else 5641 { 5642 error ("ISO C++ forbids casting to an array type %qT", type); 5643 return error_mark_node; 5644 } 5645 } 5646 5647 if (TREE_CODE (type) == FUNCTION_TYPE 5648 || TREE_CODE (type) == METHOD_TYPE) 5649 { 5650 error ("invalid cast to function type %qT", type); 5651 return error_mark_node; 5652 } 5653 5654 /* A C-style cast can be a const_cast. */ 5655 result = build_const_cast_1 (type, value, /*complain=*/false, 5656 &valid_p); 5657 if (valid_p) 5658 return result; 5659 5660 /* Or a static cast. */ 5661 result = build_static_cast_1 (type, value, /*c_cast_p=*/true, 5662 &valid_p); 5663 /* Or a reinterpret_cast. */ 5664 if (!valid_p) 5665 result = build_reinterpret_cast_1 (type, value, /*c_cast_p=*/true, 5666 &valid_p); 5667 /* The static_cast or reinterpret_cast may be followed by a 5668 const_cast. */ 5669 if (valid_p 5670 /* A valid cast may result in errors if, for example, a 5671 conversion to am ambiguous base class is required. */ 5672 && !error_operand_p (result)) 5673 { 5674 tree result_type; 5675 5676 /* Non-class rvalues always have cv-unqualified type. */ 5677 if (!CLASS_TYPE_P (type)) 5678 type = TYPE_MAIN_VARIANT (type); 5679 result_type = TREE_TYPE (result); 5680 if (!CLASS_TYPE_P (result_type)) 5681 result_type = TYPE_MAIN_VARIANT (result_type); 5682 /* If the type of RESULT does not match TYPE, perform a 5683 const_cast to make it match. If the static_cast or 5684 reinterpret_cast succeeded, we will differ by at most 5685 cv-qualification, so the follow-on const_cast is guaranteed 5686 to succeed. */ 5687 if (!same_type_p (non_reference (type), non_reference (result_type))) 5688 { 5689 result = build_const_cast_1 (type, result, false, &valid_p); 5690 gcc_assert (valid_p); 5691 } 5692 return result; 5693 } 5694 5695 return error_mark_node; 5696} 5697 5698/* Build an assignment expression of lvalue LHS from value RHS. 5699 MODIFYCODE is the code for a binary operator that we use 5700 to combine the old value of LHS with RHS to get the new value. 5701 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment. 5702 5703 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */ 5704 5705tree 5706build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs) 5707{ 5708 tree result; 5709 tree newrhs = rhs; 5710 tree lhstype = TREE_TYPE (lhs); 5711 tree olhstype = lhstype; 5712 tree olhs = NULL_TREE; 5713 bool plain_assign = (modifycode == NOP_EXPR); 5714 5715 /* Avoid duplicate error messages from operands that had errors. */ 5716 if (error_operand_p (lhs) || error_operand_p (rhs)) 5717 return error_mark_node; 5718 5719 /* Handle control structure constructs used as "lvalues". */ 5720 switch (TREE_CODE (lhs)) 5721 { 5722 /* Handle --foo = 5; as these are valid constructs in C++. */ 5723 case PREDECREMENT_EXPR: 5724 case PREINCREMENT_EXPR: 5725 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0))) 5726 lhs = build2 (TREE_CODE (lhs), TREE_TYPE (lhs), 5727 stabilize_reference (TREE_OPERAND (lhs, 0)), 5728 TREE_OPERAND (lhs, 1)); 5729 return build2 (COMPOUND_EXPR, lhstype, 5730 lhs, 5731 build_modify_expr (TREE_OPERAND (lhs, 0), 5732 modifycode, rhs)); 5733 5734 /* Handle (a, b) used as an "lvalue". */ 5735 case COMPOUND_EXPR: 5736 newrhs = build_modify_expr (TREE_OPERAND (lhs, 1), 5737 modifycode, rhs); 5738 if (newrhs == error_mark_node) 5739 return error_mark_node; 5740 return build2 (COMPOUND_EXPR, lhstype, 5741 TREE_OPERAND (lhs, 0), newrhs); 5742 5743 case MODIFY_EXPR: 5744 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0))) 5745 lhs = build2 (TREE_CODE (lhs), TREE_TYPE (lhs), 5746 stabilize_reference (TREE_OPERAND (lhs, 0)), 5747 TREE_OPERAND (lhs, 1)); 5748 newrhs = build_modify_expr (TREE_OPERAND (lhs, 0), modifycode, rhs); 5749 if (newrhs == error_mark_node) 5750 return error_mark_node; 5751 return build2 (COMPOUND_EXPR, lhstype, lhs, newrhs); 5752 5753 case MIN_EXPR: 5754 case MAX_EXPR: 5755 /* MIN_EXPR and MAX_EXPR are currently only permitted as lvalues, 5756 when neither operand has side-effects. */ 5757 if (!lvalue_or_else (lhs, lv_assign)) 5758 return error_mark_node; 5759 5760 gcc_assert (!TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)) 5761 && !TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 1))); 5762 5763 lhs = build3 (COND_EXPR, TREE_TYPE (lhs), 5764 build2 (TREE_CODE (lhs) == MIN_EXPR ? LE_EXPR : GE_EXPR, 5765 boolean_type_node, 5766 TREE_OPERAND (lhs, 0), 5767 TREE_OPERAND (lhs, 1)), 5768 TREE_OPERAND (lhs, 0), 5769 TREE_OPERAND (lhs, 1)); 5770 /* Fall through. */ 5771 5772 /* Handle (a ? b : c) used as an "lvalue". */ 5773 case COND_EXPR: 5774 { 5775 /* Produce (a ? (b = rhs) : (c = rhs)) 5776 except that the RHS goes through a save-expr 5777 so the code to compute it is only emitted once. */ 5778 tree cond; 5779 tree preeval = NULL_TREE; 5780 5781 if (VOID_TYPE_P (TREE_TYPE (rhs))) 5782 { 5783 error ("void value not ignored as it ought to be"); 5784 return error_mark_node; 5785 } 5786 5787 rhs = stabilize_expr (rhs, &preeval); 5788 5789 /* Check this here to avoid odd errors when trying to convert 5790 a throw to the type of the COND_EXPR. */ 5791 if (!lvalue_or_else (lhs, lv_assign)) 5792 return error_mark_node; 5793 5794 cond = build_conditional_expr 5795 (TREE_OPERAND (lhs, 0), 5796 build_modify_expr (TREE_OPERAND (lhs, 1), 5797 modifycode, rhs), 5798 build_modify_expr (TREE_OPERAND (lhs, 2), 5799 modifycode, rhs)); 5800 5801 if (cond == error_mark_node) 5802 return cond; 5803 /* Make sure the code to compute the rhs comes out 5804 before the split. */ 5805 if (preeval) 5806 cond = build2 (COMPOUND_EXPR, TREE_TYPE (lhs), preeval, cond); 5807 return cond; 5808 } 5809 5810 default: 5811 break; 5812 } 5813 5814 if (modifycode == INIT_EXPR) 5815 { 5816 if (TREE_CODE (rhs) == CONSTRUCTOR) 5817 { 5818 if (! same_type_p (TREE_TYPE (rhs), lhstype)) 5819 /* Call convert to generate an error; see PR 11063. */ 5820 rhs = convert (lhstype, rhs); 5821 result = build2 (INIT_EXPR, lhstype, lhs, rhs); 5822 TREE_SIDE_EFFECTS (result) = 1; 5823 return result; 5824 } 5825 else if (! IS_AGGR_TYPE (lhstype)) 5826 /* Do the default thing. */; 5827 else 5828 { 5829 result = build_special_member_call (lhs, complete_ctor_identifier, 5830 build_tree_list (NULL_TREE, rhs), 5831 lhstype, LOOKUP_NORMAL); 5832 if (result == NULL_TREE) 5833 return error_mark_node; 5834 return result; 5835 } 5836 } 5837 else 5838 { 5839 lhs = require_complete_type (lhs); 5840 if (lhs == error_mark_node) 5841 return error_mark_node; 5842 5843 if (modifycode == NOP_EXPR) 5844 { 5845 /* `operator=' is not an inheritable operator. */ 5846 if (! IS_AGGR_TYPE (lhstype)) 5847 /* Do the default thing. */; 5848 else 5849 { 5850 result = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, 5851 lhs, rhs, make_node (NOP_EXPR), 5852 /*overloaded_p=*/NULL); 5853 if (result == NULL_TREE) 5854 return error_mark_node; 5855 return result; 5856 } 5857 /* APPLE LOCAL end C* property (Radar 4436866) */ 5858 /* `operator=' is not an inheritable operator. */ 5859 if (! IS_AGGR_TYPE (lhstype)) 5860 /* Do the default thing. */; 5861 else 5862 { 5863 result = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, 5864 lhs, rhs, make_node (NOP_EXPR), 5865 /*overloaded_p=*/NULL); 5866 if (result == NULL_TREE) 5867 return error_mark_node; 5868 return result; 5869 } 5870 lhstype = olhstype; 5871 } 5872 else 5873 { 5874 /* A binary op has been requested. Combine the old LHS 5875 value with the RHS producing the value we should actually 5876 store into the LHS. */ 5877 5878 gcc_assert (!PROMOTES_TO_AGGR_TYPE (lhstype, REFERENCE_TYPE)); 5879 lhs = stabilize_reference (lhs); 5880 newrhs = cp_build_binary_op (modifycode, lhs, rhs); 5881 if (newrhs == error_mark_node) 5882 { 5883 error (" in evaluation of %<%Q(%#T, %#T)%>", modifycode, 5884 TREE_TYPE (lhs), TREE_TYPE (rhs)); 5885 return error_mark_node; 5886 } 5887 5888 /* Now it looks like a plain assignment. */ 5889 modifycode = NOP_EXPR; 5890 lhstype = olhstype; 5891 } 5892 gcc_assert (TREE_CODE (lhstype) != REFERENCE_TYPE); 5893 gcc_assert (TREE_CODE (TREE_TYPE (newrhs)) != REFERENCE_TYPE); 5894 } 5895 5896 /* The left-hand side must be an lvalue. */ 5897 if (!lvalue_or_else (lhs, lv_assign)) 5898 return error_mark_node; 5899 5900 /* Warn about modifying something that is `const'. Don't warn if 5901 this is initialization. */ 5902 if (modifycode != INIT_EXPR 5903 && (TREE_READONLY (lhs) || CP_TYPE_CONST_P (lhstype) 5904 /* Functions are not modifiable, even though they are 5905 lvalues. */ 5906 || TREE_CODE (TREE_TYPE (lhs)) == FUNCTION_TYPE 5907 || TREE_CODE (TREE_TYPE (lhs)) == METHOD_TYPE 5908 /* If it's an aggregate and any field is const, then it is 5909 effectively const. */ 5910 || (CLASS_TYPE_P (lhstype) 5911 && C_TYPE_FIELDS_READONLY (lhstype)))) 5912 readonly_error (lhs, "assignment", 0); 5913 5914 /* If storing into a structure or union member, it has probably been 5915 given type `int'. Compute the type that would go with the actual 5916 amount of storage the member occupies. */ 5917 5918 if (TREE_CODE (lhs) == COMPONENT_REF 5919 && (TREE_CODE (lhstype) == INTEGER_TYPE 5920 || TREE_CODE (lhstype) == REAL_TYPE 5921 || TREE_CODE (lhstype) == ENUMERAL_TYPE)) 5922 { 5923 lhstype = TREE_TYPE (get_unwidened (lhs, 0)); 5924 5925 /* If storing in a field that is in actuality a short or narrower 5926 than one, we must store in the field in its actual type. */ 5927 5928 if (lhstype != TREE_TYPE (lhs)) 5929 { 5930 /* Avoid warnings converting integral types back into enums for 5931 enum bit fields. */ 5932 if (TREE_CODE (lhstype) == INTEGER_TYPE 5933 && TREE_CODE (olhstype) == ENUMERAL_TYPE) 5934 { 5935 if (TREE_SIDE_EFFECTS (lhs)) 5936 lhs = stabilize_reference (lhs); 5937 olhs = lhs; 5938 } 5939 lhs = copy_node (lhs); 5940 TREE_TYPE (lhs) = lhstype; 5941 } 5942 } 5943 5944 /* Convert new value to destination type. */ 5945 5946 if (TREE_CODE (lhstype) == ARRAY_TYPE) 5947 { 5948 int from_array; 5949 5950 if (!same_or_base_type_p (TYPE_MAIN_VARIANT (lhstype), 5951 TYPE_MAIN_VARIANT (TREE_TYPE (rhs)))) 5952 { 5953 error ("incompatible types in assignment of %qT to %qT", 5954 TREE_TYPE (rhs), lhstype); 5955 return error_mark_node; 5956 } 5957 5958 /* Allow array assignment in compiler-generated code. */ 5959 if (! DECL_ARTIFICIAL (current_function_decl)) 5960 { 5961 /* This routine is used for both initialization and assignment. 5962 Make sure the diagnostic message differentiates the context. */ 5963 if (modifycode == INIT_EXPR) 5964 error ("array used as initializer"); 5965 else 5966 error ("invalid array assignment"); 5967 return error_mark_node; 5968 } 5969 5970 from_array = TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE 5971 ? 1 + (modifycode != INIT_EXPR): 0; 5972 return build_vec_init (lhs, NULL_TREE, newrhs, 5973 /*explicit_default_init_p=*/false, 5974 from_array); 5975 } 5976 5977 if (modifycode == INIT_EXPR) 5978 newrhs = convert_for_initialization (lhs, lhstype, newrhs, LOOKUP_NORMAL, 5979 "initialization", NULL_TREE, 0); 5980 else 5981 { 5982 /* Avoid warnings on enum bit fields. */ 5983 if (TREE_CODE (olhstype) == ENUMERAL_TYPE 5984 && TREE_CODE (lhstype) == INTEGER_TYPE) 5985 { 5986 newrhs = convert_for_assignment (olhstype, newrhs, "assignment", 5987 NULL_TREE, 0); 5988 newrhs = convert_force (lhstype, newrhs, 0); 5989 } 5990 else 5991 newrhs = convert_for_assignment (lhstype, newrhs, "assignment", 5992 NULL_TREE, 0); 5993 if (TREE_CODE (newrhs) == CALL_EXPR 5994 && TYPE_NEEDS_CONSTRUCTING (lhstype)) 5995 newrhs = build_cplus_new (lhstype, newrhs); 5996 5997 /* Can't initialize directly from a TARGET_EXPR, since that would 5998 cause the lhs to be constructed twice, and possibly result in 5999 accidental self-initialization. So we force the TARGET_EXPR to be 6000 expanded without a target. */ 6001 if (TREE_CODE (newrhs) == TARGET_EXPR) 6002 newrhs = build2 (COMPOUND_EXPR, TREE_TYPE (newrhs), newrhs, 6003 TREE_OPERAND (newrhs, 0)); 6004 } 6005 6006 if (newrhs == error_mark_node) 6007 return error_mark_node; 6008 6009 if (c_dialect_objc () && flag_objc_gc) 6010 { 6011 result = objc_generate_write_barrier (lhs, modifycode, newrhs); 6012 6013 if (result) 6014 return result; 6015 } 6016 6017 result = build2 (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR, 6018 lhstype, lhs, newrhs); 6019 6020 TREE_SIDE_EFFECTS (result) = 1; 6021 if (!plain_assign) 6022 TREE_NO_WARNING (result) = 1; 6023 6024 /* If we got the LHS in a different type for storing in, 6025 convert the result back to the nominal type of LHS 6026 so that the value we return always has the same type 6027 as the LHS argument. */ 6028 6029 if (olhstype == TREE_TYPE (result)) 6030 return result; 6031 if (olhs) 6032 { 6033 result = build2 (COMPOUND_EXPR, olhstype, result, olhs); 6034 TREE_NO_WARNING (result) = 1; 6035 return result; 6036 } 6037 return convert_for_assignment (olhstype, result, "assignment", 6038 NULL_TREE, 0); 6039} 6040 6041tree 6042build_x_modify_expr (tree lhs, enum tree_code modifycode, tree rhs) 6043{ 6044 /* APPLE LOCAL __block assign sequence point 6639533 */ 6045 bool insert_sequence_point = false; 6046 6047 if (processing_template_decl) 6048 return build_min_nt (MODOP_EXPR, lhs, 6049 build_min_nt (modifycode, NULL_TREE, NULL_TREE), rhs); 6050 6051 /* APPLE LOCAL begin __block assign sequence point 6639533 */ 6052 /* For byref = x;, we have to transform this into ({ typeof(x) x' = 6053 x; byref = x`; )} to ensure there is a sequence point before the 6054 evaluation of the byref, inorder to ensure that the access 6055 expression for byref doesn't start running before x is evaluated, 6056 as it will access the __forwarding pointer and that must be done 6057 after x is evaluated. */ 6058 /* First we check to see if lhs is a byref... byrefs look like: 6059 __Block_byref_X.__forwarding->x */ 6060 if (TREE_CODE (lhs) == COMPONENT_REF) 6061 { 6062 tree inner = TREE_OPERAND (lhs, 0); 6063 /* now check for -> */ 6064 if (TREE_CODE (inner) == INDIRECT_REF) 6065 { 6066 inner = TREE_OPERAND (inner, 0); 6067 if (TREE_CODE (inner) == COMPONENT_REF) 6068 { 6069 inner = TREE_OPERAND (inner, 0); 6070 if (TREE_CODE (inner) == VAR_DECL 6071 && COPYABLE_BYREF_LOCAL_VAR (inner)) 6072 { 6073 tree old_rhs = rhs; 6074 /* then we save the rhs. */ 6075 rhs = save_expr (rhs); 6076 if (rhs != old_rhs) 6077 /* And arrange for the sequence point to be inserted. */ 6078 insert_sequence_point = true; 6079 } 6080 } 6081 } 6082 } 6083 /* APPLE LOCAL end __block assign sequence point 6639533 */ 6084 6085 if (modifycode != NOP_EXPR) 6086 { 6087 tree rval = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, lhs, rhs, 6088 make_node (modifycode), 6089 /*overloaded_p=*/NULL); 6090 if (rval) 6091 { 6092 /* APPLE LOCAL begin __block assign sequence point 6639533 */ 6093 if (insert_sequence_point) 6094 rval = build2 (COMPOUND_EXPR, TREE_TYPE (rval), rhs, rval); 6095 /* APPLE LOCAL end __block assign sequence point 6639533 */ 6096 TREE_NO_WARNING (rval) = 1; 6097 return rval; 6098 } 6099 } 6100 lhs = build_modify_expr (lhs, modifycode, rhs); 6101 /* APPLE LOCAL begin __block assign sequence point 6639533 */ 6102 if (insert_sequence_point) 6103 lhs = build2 (COMPOUND_EXPR, TREE_TYPE (lhs), rhs, lhs); 6104 /* APPLE LOCAL end __block assign sequence point 6639533 */ 6105 return lhs; 6106} 6107 6108 6109/* Get difference in deltas for different pointer to member function 6110 types. Returns an integer constant of type PTRDIFF_TYPE_NODE. If 6111 the conversion is invalid, the constant is zero. If 6112 ALLOW_INVERSE_P is true, then allow reverse conversions as well. 6113 If C_CAST_P is true this conversion is taking place as part of a 6114 C-style cast. 6115 6116 Note that the naming of FROM and TO is kind of backwards; the return 6117 value is what we add to a TO in order to get a FROM. They are named 6118 this way because we call this function to find out how to convert from 6119 a pointer to member of FROM to a pointer to member of TO. */ 6120 6121static tree 6122get_delta_difference (tree from, tree to, 6123 bool allow_inverse_p, 6124 bool c_cast_p) 6125{ 6126 tree binfo; 6127 base_kind kind; 6128 tree result; 6129 6130 /* Assume no conversion is required. */ 6131 result = integer_zero_node; 6132 binfo = lookup_base (to, from, c_cast_p ? ba_unique : ba_check, &kind); 6133 if (kind == bk_inaccessible || kind == bk_ambig) 6134 error (" in pointer to member function conversion"); 6135 else if (binfo) 6136 { 6137 if (kind != bk_via_virtual) 6138 result = BINFO_OFFSET (binfo); 6139 else 6140 { 6141 tree virt_binfo = binfo_from_vbase (binfo); 6142 6143 /* This is a reinterpret cast, we choose to do nothing. */ 6144 if (allow_inverse_p) 6145 warning (0, "pointer to member cast via virtual base %qT", 6146 BINFO_TYPE (virt_binfo)); 6147 else 6148 error ("pointer to member conversion via virtual base %qT", 6149 BINFO_TYPE (virt_binfo)); 6150 } 6151 } 6152 else if (same_type_ignoring_top_level_qualifiers_p (from, to)) 6153 /* Pointer to member of incomplete class is permitted*/; 6154 else if (!allow_inverse_p) 6155 { 6156 error_not_base_type (from, to); 6157 error (" in pointer to member conversion"); 6158 } 6159 else 6160 { 6161 binfo = lookup_base (from, to, c_cast_p ? ba_unique : ba_check, &kind); 6162 if (binfo) 6163 { 6164 if (kind != bk_via_virtual) 6165 result = size_diffop (size_zero_node, BINFO_OFFSET (binfo)); 6166 else 6167 { 6168 /* This is a reinterpret cast, we choose to do nothing. */ 6169 tree virt_binfo = binfo_from_vbase (binfo); 6170 6171 warning (0, "pointer to member cast via virtual base %qT", 6172 BINFO_TYPE (virt_binfo)); 6173 } 6174 } 6175 } 6176 6177 return fold_if_not_in_template (convert_to_integer (ptrdiff_type_node, 6178 result)); 6179} 6180 6181/* Return a constructor for the pointer-to-member-function TYPE using 6182 the other components as specified. */ 6183 6184tree 6185build_ptrmemfunc1 (tree type, tree delta, tree pfn) 6186{ 6187 tree u = NULL_TREE; 6188 tree delta_field; 6189 tree pfn_field; 6190 VEC(constructor_elt, gc) *v; 6191 6192 /* Pull the FIELD_DECLs out of the type. */ 6193 pfn_field = TYPE_FIELDS (type); 6194 delta_field = TREE_CHAIN (pfn_field); 6195 6196 /* Make sure DELTA has the type we want. */ 6197 delta = convert_and_check (delta_type_node, delta); 6198 6199 /* Finish creating the initializer. */ 6200 v = VEC_alloc(constructor_elt, gc, 2); 6201 CONSTRUCTOR_APPEND_ELT(v, pfn_field, pfn); 6202 CONSTRUCTOR_APPEND_ELT(v, delta_field, delta); 6203 u = build_constructor (type, v); 6204 TREE_CONSTANT (u) = TREE_CONSTANT (pfn) & TREE_CONSTANT (delta); 6205 TREE_INVARIANT (u) = TREE_INVARIANT (pfn) & TREE_INVARIANT (delta); 6206 TREE_STATIC (u) = (TREE_CONSTANT (u) 6207 && (initializer_constant_valid_p (pfn, TREE_TYPE (pfn)) 6208 != NULL_TREE) 6209 && (initializer_constant_valid_p (delta, TREE_TYPE (delta)) 6210 != NULL_TREE)); 6211 return u; 6212} 6213 6214/* Build a constructor for a pointer to member function. It can be 6215 used to initialize global variables, local variable, or used 6216 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we 6217 want to be. 6218 6219 If FORCE is nonzero, then force this conversion, even if 6220 we would rather not do it. Usually set when using an explicit 6221 cast. A C-style cast is being processed iff C_CAST_P is true. 6222 6223 Return error_mark_node, if something goes wrong. */ 6224 6225tree 6226build_ptrmemfunc (tree type, tree pfn, int force, bool c_cast_p) 6227{ 6228 tree fn; 6229 tree pfn_type; 6230 tree to_type; 6231 6232 if (error_operand_p (pfn)) 6233 return error_mark_node; 6234 6235 pfn_type = TREE_TYPE (pfn); 6236 to_type = build_ptrmemfunc_type (type); 6237 6238 /* Handle multiple conversions of pointer to member functions. */ 6239 if (TYPE_PTRMEMFUNC_P (pfn_type)) 6240 { 6241 tree delta = NULL_TREE; 6242 tree npfn = NULL_TREE; 6243 tree n; 6244 6245 if (!force 6246 && !can_convert_arg (to_type, TREE_TYPE (pfn), pfn, LOOKUP_NORMAL)) 6247 error ("invalid conversion to type %qT from type %qT", 6248 to_type, pfn_type); 6249 6250 n = get_delta_difference (TYPE_PTRMEMFUNC_OBJECT_TYPE (pfn_type), 6251 TYPE_PTRMEMFUNC_OBJECT_TYPE (to_type), 6252 force, 6253 c_cast_p); 6254 6255 /* We don't have to do any conversion to convert a 6256 pointer-to-member to its own type. But, we don't want to 6257 just return a PTRMEM_CST if there's an explicit cast; that 6258 cast should make the expression an invalid template argument. */ 6259 if (TREE_CODE (pfn) != PTRMEM_CST) 6260 { 6261 if (same_type_p (to_type, pfn_type)) 6262 return pfn; 6263 else if (integer_zerop (n)) 6264 return build_reinterpret_cast (to_type, pfn); 6265 } 6266 6267 if (TREE_SIDE_EFFECTS (pfn)) 6268 pfn = save_expr (pfn); 6269 6270 /* Obtain the function pointer and the current DELTA. */ 6271 if (TREE_CODE (pfn) == PTRMEM_CST) 6272 expand_ptrmemfunc_cst (pfn, &delta, &npfn); 6273 else 6274 { 6275 npfn = build_ptrmemfunc_access_expr (pfn, pfn_identifier); 6276 delta = build_ptrmemfunc_access_expr (pfn, delta_identifier); 6277 } 6278 6279 /* Just adjust the DELTA field. */ 6280 gcc_assert (same_type_ignoring_top_level_qualifiers_p 6281 (TREE_TYPE (delta), ptrdiff_type_node)); 6282 if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_delta) 6283 n = cp_build_binary_op (LSHIFT_EXPR, n, integer_one_node); 6284 delta = cp_build_binary_op (PLUS_EXPR, delta, n); 6285 return build_ptrmemfunc1 (to_type, delta, npfn); 6286 } 6287 6288 /* Handle null pointer to member function conversions. */ 6289 if (integer_zerop (pfn)) 6290 { 6291 pfn = build_c_cast (type, integer_zero_node); 6292 return build_ptrmemfunc1 (to_type, 6293 integer_zero_node, 6294 pfn); 6295 } 6296 6297 if (type_unknown_p (pfn)) 6298 return instantiate_type (type, pfn, tf_warning_or_error); 6299 6300 fn = TREE_OPERAND (pfn, 0); 6301 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL 6302 /* In a template, we will have preserved the 6303 OFFSET_REF. */ 6304 || (processing_template_decl && TREE_CODE (fn) == OFFSET_REF)); 6305 return make_ptrmem_cst (to_type, fn); 6306} 6307 6308/* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST 6309 given by CST. 6310 6311 ??? There is no consistency as to the types returned for the above 6312 values. Some code acts as if it were a sizetype and some as if it were 6313 integer_type_node. */ 6314 6315void 6316expand_ptrmemfunc_cst (tree cst, tree *delta, tree *pfn) 6317{ 6318 tree type = TREE_TYPE (cst); 6319 tree fn = PTRMEM_CST_MEMBER (cst); 6320 tree ptr_class, fn_class; 6321 6322 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL); 6323 6324 /* The class that the function belongs to. */ 6325 fn_class = DECL_CONTEXT (fn); 6326 6327 /* The class that we're creating a pointer to member of. */ 6328 ptr_class = TYPE_PTRMEMFUNC_OBJECT_TYPE (type); 6329 6330 /* First, calculate the adjustment to the function's class. */ 6331 *delta = get_delta_difference (fn_class, ptr_class, /*force=*/0, 6332 /*c_cast_p=*/0); 6333 6334 if (!DECL_VIRTUAL_P (fn)) 6335 *pfn = convert (TYPE_PTRMEMFUNC_FN_TYPE (type), build_addr_func (fn)); 6336 else 6337 { 6338 /* If we're dealing with a virtual function, we have to adjust 'this' 6339 again, to point to the base which provides the vtable entry for 6340 fn; the call will do the opposite adjustment. */ 6341 tree orig_class = DECL_CONTEXT (fn); 6342 tree binfo = binfo_or_else (orig_class, fn_class); 6343 *delta = build2 (PLUS_EXPR, TREE_TYPE (*delta), 6344 *delta, BINFO_OFFSET (binfo)); 6345 *delta = fold_if_not_in_template (*delta); 6346 6347 /* We set PFN to the vtable offset at which the function can be 6348 found, plus one (unless ptrmemfunc_vbit_in_delta, in which 6349 case delta is shifted left, and then incremented). */ 6350 *pfn = DECL_VINDEX (fn); 6351 *pfn = build2 (MULT_EXPR, integer_type_node, *pfn, 6352 TYPE_SIZE_UNIT (vtable_entry_type)); 6353 *pfn = fold_if_not_in_template (*pfn); 6354 6355 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION) 6356 { 6357 case ptrmemfunc_vbit_in_pfn: 6358 *pfn = build2 (PLUS_EXPR, integer_type_node, *pfn, 6359 integer_one_node); 6360 *pfn = fold_if_not_in_template (*pfn); 6361 break; 6362 6363 case ptrmemfunc_vbit_in_delta: 6364 *delta = build2 (LSHIFT_EXPR, TREE_TYPE (*delta), 6365 *delta, integer_one_node); 6366 *delta = fold_if_not_in_template (*delta); 6367 *delta = build2 (PLUS_EXPR, TREE_TYPE (*delta), 6368 *delta, integer_one_node); 6369 *delta = fold_if_not_in_template (*delta); 6370 break; 6371 6372 default: 6373 gcc_unreachable (); 6374 } 6375 6376 *pfn = build_nop (TYPE_PTRMEMFUNC_FN_TYPE (type), *pfn); 6377 *pfn = fold_if_not_in_template (*pfn); 6378 } 6379} 6380 6381/* Return an expression for PFN from the pointer-to-member function 6382 given by T. */ 6383 6384static tree 6385pfn_from_ptrmemfunc (tree t) 6386{ 6387 if (TREE_CODE (t) == PTRMEM_CST) 6388 { 6389 tree delta; 6390 tree pfn; 6391 6392 expand_ptrmemfunc_cst (t, &delta, &pfn); 6393 if (pfn) 6394 return pfn; 6395 } 6396 6397 return build_ptrmemfunc_access_expr (t, pfn_identifier); 6398} 6399 6400/* Convert value RHS to type TYPE as preparation for an assignment to 6401 an lvalue of type TYPE. ERRTYPE is a string to use in error 6402 messages: "assignment", "return", etc. If FNDECL is non-NULL, we 6403 are doing the conversion in order to pass the PARMNUMth argument of 6404 FNDECL. */ 6405 6406static tree 6407convert_for_assignment (tree type, tree rhs, 6408 const char *errtype, tree fndecl, int parmnum) 6409{ 6410 tree rhstype; 6411 enum tree_code coder; 6412 /* APPLE LOCAL radar 4874632 */ 6413 tree new_rhs = NULL_TREE; 6414 6415 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */ 6416 if (TREE_CODE (rhs) == NON_LVALUE_EXPR) 6417 rhs = TREE_OPERAND (rhs, 0); 6418 6419 rhstype = TREE_TYPE (rhs); 6420 coder = TREE_CODE (rhstype); 6421 6422 if (TREE_CODE (type) == VECTOR_TYPE && coder == VECTOR_TYPE 6423 && vector_types_convertible_p (type, rhstype, true)) 6424 return convert (type, rhs); 6425 6426 if (rhs == error_mark_node || rhstype == error_mark_node) 6427 return error_mark_node; 6428 if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node) 6429 return error_mark_node; 6430 6431 /* The RHS of an assignment cannot have void type. */ 6432 if (coder == VOID_TYPE) 6433 { 6434 error ("void value not ignored as it ought to be"); 6435 return error_mark_node; 6436 } 6437 6438 /* Simplify the RHS if possible. */ 6439 if (TREE_CODE (rhs) == CONST_DECL) 6440 rhs = DECL_INITIAL (rhs); 6441 6442 if (c_dialect_objc ()) 6443 { 6444 int parmno; 6445 tree rname = fndecl; 6446 6447 if (!strcmp (errtype, "assignment")) 6448 parmno = -1; 6449 else if (!strcmp (errtype, "initialization")) 6450 parmno = -2; 6451 else 6452 { 6453 tree selector = objc_message_selector (); 6454 6455 parmno = parmnum; 6456 6457 if (selector && parmno > 1) 6458 { 6459 rname = selector; 6460 parmno -= 1; 6461 } 6462 } 6463 6464 /* APPLE LOCAL file radar 6231433 */ 6465 if (objc_compare_types (type, rhstype, parmno, rname, "comparison")) 6466 /* APPLE LOCAL radar 4874632 */ 6467 new_rhs = convert (type, rhs); 6468 } 6469 6470 /* [expr.ass] 6471 6472 The expression is implicitly converted (clause _conv_) to the 6473 cv-unqualified type of the left operand. 6474 6475 We allow bad conversions here because by the time we get to this point 6476 we are committed to doing the conversion. If we end up doing a bad 6477 conversion, convert_like will complain. */ 6478 if (!can_convert_arg_bad (type, rhstype, rhs)) 6479 { 6480 /* When -Wno-pmf-conversions is use, we just silently allow 6481 conversions from pointers-to-members to plain pointers. If 6482 the conversion doesn't work, cp_convert will complain. */ 6483 if (!warn_pmf2ptr 6484 && TYPE_PTR_P (type) 6485 && TYPE_PTRMEMFUNC_P (rhstype)) 6486 rhs = cp_convert (strip_top_quals (type), rhs); 6487 else 6488 { 6489 /* If the right-hand side has unknown type, then it is an 6490 overloaded function. Call instantiate_type to get error 6491 messages. */ 6492 if (rhstype == unknown_type_node) 6493 instantiate_type (type, rhs, tf_warning_or_error); 6494 else if (fndecl) 6495 error ("cannot convert %qT to %qT for argument %qP to %qD", 6496 rhstype, type, parmnum, fndecl); 6497 else 6498 error ("cannot convert %qT to %qT in %s", rhstype, type, errtype); 6499 return error_mark_node; 6500 } 6501 } 6502 if (warn_missing_format_attribute) 6503 { 6504 const enum tree_code codel = TREE_CODE (type); 6505 if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE) 6506 && coder == codel 6507 && check_missing_format_attribute (type, rhstype)) 6508 warning (OPT_Wmissing_format_attribute, 6509 "%s might be a candidate for a format attribute", 6510 errtype); 6511 } 6512 6513 /* If -Wparentheses, warn about a = b = c when a has type bool and b 6514 does not. */ 6515 if (warn_parentheses 6516 && type == boolean_type_node 6517 && TREE_CODE (rhs) == MODIFY_EXPR 6518 && !TREE_NO_WARNING (rhs) 6519 && TREE_TYPE (rhs) != boolean_type_node) 6520 { 6521 warning (OPT_Wparentheses, 6522 "suggest parentheses around assignment used as truth value"); 6523 TREE_NO_WARNING (rhs) = 1; 6524 } 6525 6526 return perform_implicit_conversion (strip_top_quals (type), rhs); 6527} 6528 6529/* Convert RHS to be of type TYPE. 6530 If EXP is nonzero, it is the target of the initialization. 6531 ERRTYPE is a string to use in error messages. 6532 6533 Two major differences between the behavior of 6534 `convert_for_assignment' and `convert_for_initialization' 6535 are that references are bashed in the former, while 6536 copied in the latter, and aggregates are assigned in 6537 the former (operator=) while initialized in the 6538 latter (X(X&)). 6539 6540 If using constructor make sure no conversion operator exists, if one does 6541 exist, an ambiguity exists. 6542 6543 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */ 6544 6545tree 6546convert_for_initialization (tree exp, tree type, tree rhs, int flags, 6547 const char *errtype, tree fndecl, int parmnum) 6548{ 6549 enum tree_code codel = TREE_CODE (type); 6550 tree rhstype; 6551 enum tree_code coder; 6552 6553 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 6554 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */ 6555 if (TREE_CODE (rhs) == NOP_EXPR 6556 && TREE_TYPE (rhs) == TREE_TYPE (TREE_OPERAND (rhs, 0)) 6557 && codel != REFERENCE_TYPE) 6558 rhs = TREE_OPERAND (rhs, 0); 6559 6560 if (type == error_mark_node 6561 || rhs == error_mark_node 6562 || (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)) 6563 return error_mark_node; 6564 6565 if ((TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE 6566 && TREE_CODE (type) != ARRAY_TYPE 6567 && (TREE_CODE (type) != REFERENCE_TYPE 6568 || TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE)) 6569 || (TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE 6570 && (TREE_CODE (type) != REFERENCE_TYPE 6571 || TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)) 6572 || TREE_CODE (TREE_TYPE (rhs)) == METHOD_TYPE) 6573 rhs = decay_conversion (rhs); 6574 6575 rhstype = TREE_TYPE (rhs); 6576 coder = TREE_CODE (rhstype); 6577 6578 if (coder == ERROR_MARK) 6579 return error_mark_node; 6580 6581 /* We accept references to incomplete types, so we can 6582 return here before checking if RHS is of complete type. */ 6583 6584 if (codel == REFERENCE_TYPE) 6585 { 6586 /* This should eventually happen in convert_arguments. */ 6587 int savew = 0, savee = 0; 6588 6589 if (fndecl) 6590 savew = warningcount, savee = errorcount; 6591 rhs = initialize_reference (type, rhs, /*decl=*/NULL_TREE, 6592 /*cleanup=*/NULL); 6593 if (fndecl) 6594 { 6595 if (warningcount > savew) 6596 warning (0, "in passing argument %P of %q+D", parmnum, fndecl); 6597 else if (errorcount > savee) 6598 error ("in passing argument %P of %q+D", parmnum, fndecl); 6599 } 6600 return rhs; 6601 } 6602 6603 if (exp != 0) 6604 exp = require_complete_type (exp); 6605 if (exp == error_mark_node) 6606 return error_mark_node; 6607 6608 rhstype = non_reference (rhstype); 6609 6610 type = complete_type (type); 6611 6612 if (IS_AGGR_TYPE (type)) 6613 return ocp_convert (type, rhs, CONV_IMPLICIT|CONV_FORCE_TEMP, flags); 6614 6615 return convert_for_assignment (type, rhs, errtype, fndecl, parmnum); 6616} 6617 6618/* If RETVAL is the address of, or a reference to, a local variable or 6619 temporary give an appropriate warning. */ 6620 6621static void 6622maybe_warn_about_returning_address_of_local (tree retval) 6623{ 6624 tree valtype = TREE_TYPE (DECL_RESULT (current_function_decl)); 6625 tree whats_returned = retval; 6626 6627 for (;;) 6628 { 6629 if (TREE_CODE (whats_returned) == COMPOUND_EXPR) 6630 whats_returned = TREE_OPERAND (whats_returned, 1); 6631 else if (TREE_CODE (whats_returned) == CONVERT_EXPR 6632 || TREE_CODE (whats_returned) == NON_LVALUE_EXPR 6633 || TREE_CODE (whats_returned) == NOP_EXPR) 6634 whats_returned = TREE_OPERAND (whats_returned, 0); 6635 else 6636 break; 6637 } 6638 6639 if (TREE_CODE (whats_returned) != ADDR_EXPR) 6640 return; 6641 whats_returned = TREE_OPERAND (whats_returned, 0); 6642 6643 if (TREE_CODE (valtype) == REFERENCE_TYPE) 6644 { 6645 if (TREE_CODE (whats_returned) == AGGR_INIT_EXPR 6646 || TREE_CODE (whats_returned) == TARGET_EXPR) 6647 { 6648 warning (0, "returning reference to temporary"); 6649 return; 6650 } 6651 if (TREE_CODE (whats_returned) == VAR_DECL 6652 && DECL_NAME (whats_returned) 6653 && TEMP_NAME_P (DECL_NAME (whats_returned))) 6654 { 6655 warning (0, "reference to non-lvalue returned"); 6656 return; 6657 } 6658 } 6659 6660 while (TREE_CODE (whats_returned) == COMPONENT_REF 6661 || TREE_CODE (whats_returned) == ARRAY_REF) 6662 whats_returned = TREE_OPERAND (whats_returned, 0); 6663 6664 if (DECL_P (whats_returned) 6665 && DECL_NAME (whats_returned) 6666 && DECL_FUNCTION_SCOPE_P (whats_returned) 6667 && !(TREE_STATIC (whats_returned) 6668 || TREE_PUBLIC (whats_returned))) 6669 { 6670 if (TREE_CODE (valtype) == REFERENCE_TYPE) 6671 warning (0, "reference to local variable %q+D returned", 6672 whats_returned); 6673 /* APPLE LOCAL begin blocks 6040305 (cn) */ 6674 else if (TREE_CODE (valtype) == BLOCK_POINTER_TYPE) 6675 error ("returning block that lives on the local stack"); 6676 /* APPLE LOCAL end blocks 6040305 (cn) */ 6677 else 6678 warning (0, "address of local variable %q+D returned", 6679 whats_returned); 6680 return; 6681 } 6682} 6683 6684/* APPLE LOCAL begin blocks 6040305 (cm) */ 6685static bool 6686types_are_block_compatible (tree t1, tree t2) 6687{ 6688 return comptypes (t1, t2, COMPARE_STRICT); 6689} 6690/* APPLE LOCAL end blocks 6040305 (cm) */ 6691 6692/* Check that returning RETVAL from the current function is valid. 6693 Return an expression explicitly showing all conversions required to 6694 change RETVAL into the function return type, and to assign it to 6695 the DECL_RESULT for the function. Set *NO_WARNING to true if 6696 code reaches end of non-void function warning shouldn't be issued 6697 on this RETURN_EXPR. */ 6698 6699tree 6700check_return_expr (tree retval, bool *no_warning) 6701{ 6702 tree result; 6703 /* The type actually returned by the function, after any 6704 promotions. */ 6705 tree valtype; 6706 int fn_returns_value_p; 6707 6708 *no_warning = false; 6709 6710 /* A `volatile' function is one that isn't supposed to return, ever. 6711 (This is a G++ extension, used to get better code for functions 6712 that call the `volatile' function.) */ 6713 if (TREE_THIS_VOLATILE (current_function_decl)) 6714 warning (0, "function declared %<noreturn%> has a %<return%> statement"); 6715 6716 /* Check for various simple errors. */ 6717 if (DECL_DESTRUCTOR_P (current_function_decl)) 6718 { 6719 if (retval) 6720 error ("returning a value from a destructor"); 6721 return NULL_TREE; 6722 } 6723 else if (DECL_CONSTRUCTOR_P (current_function_decl)) 6724 { 6725 if (in_function_try_handler) 6726 /* If a return statement appears in a handler of the 6727 function-try-block of a constructor, the program is ill-formed. */ 6728 error ("cannot return from a handler of a function-try-block of a constructor"); 6729 else if (retval) 6730 /* You can't return a value from a constructor. */ 6731 error ("returning a value from a constructor"); 6732 return NULL_TREE; 6733 } 6734 6735 /* APPLE LOCAL begin blocks 6040305 (cm) */ 6736 /* APPLE LOCAL radar 6185344 */ 6737 if (cur_block && !cur_block->block_has_return_type) 6738 { 6739 /* If this is the first return we've seen in the block, infer the type of 6740 the block from it. */ 6741 if (cur_block->return_type == NULL_TREE) 6742 { 6743 if (retval) 6744 { 6745 tree restype; 6746 retval = decay_conversion (retval); 6747 restype = TYPE_MAIN_VARIANT (TREE_TYPE (retval)); 6748 TREE_TYPE (current_function_decl) 6749 = build_function_type (restype, 6750 TYPE_ARG_TYPES (TREE_TYPE (current_function_decl))); 6751 TREE_TYPE (DECL_RESULT (current_function_decl)) = restype; 6752 relayout_decl (DECL_RESULT (current_function_decl)); 6753 cur_block->return_type = restype; 6754 } 6755 else 6756 cur_block->return_type = void_type_node; 6757 } 6758 6759 /* Verify that this result type matches the previous one. We 6760 are pickier with blocks than for normal functions because 6761 this is a new feature and we set the rules. */ 6762 if (TREE_CODE (cur_block->return_type) == VOID_TYPE) 6763 { 6764 if (retval) 6765 { 6766 error ("void block should not return a value"); 6767 return error_mark_node; 6768 } 6769 } 6770 else if (!retval) 6771 { 6772 error ("non-void block should return a value"); 6773 return error_mark_node; 6774 } 6775 6776 if (retval) 6777 { 6778 /* We have a non-void block with an expression, continue checking. */ 6779 valtype = TREE_TYPE (retval); 6780 6781 /* For now, restrict multiple return statements in a block to have 6782 strict compatible types only. */ 6783 if (!types_are_block_compatible (cur_block->return_type, valtype)) 6784 { 6785 error ("incompatible type returning %qT, expected %qT", 6786 valtype, cur_block->return_type); 6787 return error_mark_node; 6788 } 6789 } 6790 } 6791 /* APPLE LOCAL end blocks 6040305 (cm) */ 6792 6793 if (processing_template_decl) 6794 { 6795 current_function_returns_value = 1; 6796 return retval; 6797 } 6798 6799 /* When no explicit return-value is given in a function with a named 6800 return value, the named return value is used. */ 6801 result = DECL_RESULT (current_function_decl); 6802 valtype = TREE_TYPE (result); 6803 gcc_assert (valtype != NULL_TREE); 6804 fn_returns_value_p = !VOID_TYPE_P (valtype); 6805 if (!retval && DECL_NAME (result) && fn_returns_value_p) 6806 retval = result; 6807 6808 /* Check for a return statement with no return value in a function 6809 that's supposed to return a value. */ 6810 if (!retval && fn_returns_value_p) 6811 { 6812 pedwarn ("return-statement with no value, in function returning %qT", 6813 valtype); 6814 /* Clear this, so finish_function won't say that we reach the 6815 end of a non-void function (which we don't, we gave a 6816 return!). */ 6817 current_function_returns_null = 0; 6818 /* And signal caller that TREE_NO_WARNING should be set on the 6819 RETURN_EXPR to avoid control reaches end of non-void function 6820 warnings in tree-cfg.c. */ 6821 *no_warning = true; 6822 } 6823 /* Check for a return statement with a value in a function that 6824 isn't supposed to return a value. */ 6825 else if (retval && !fn_returns_value_p) 6826 { 6827 if (VOID_TYPE_P (TREE_TYPE (retval))) 6828 /* You can return a `void' value from a function of `void' 6829 type. In that case, we have to evaluate the expression for 6830 its side-effects. */ 6831 finish_expr_stmt (retval); 6832 else 6833 pedwarn ("return-statement with a value, in function " 6834 "returning 'void'"); 6835 6836 current_function_returns_null = 1; 6837 6838 /* There's really no value to return, after all. */ 6839 return NULL_TREE; 6840 } 6841 else if (!retval) 6842 /* Remember that this function can sometimes return without a 6843 value. */ 6844 current_function_returns_null = 1; 6845 else 6846 /* Remember that this function did return a value. */ 6847 current_function_returns_value = 1; 6848 6849 /* Check for erroneous operands -- but after giving ourselves a 6850 chance to provide an error about returning a value from a void 6851 function. */ 6852 if (error_operand_p (retval)) 6853 { 6854 current_function_return_value = error_mark_node; 6855 return error_mark_node; 6856 } 6857 6858 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */ 6859 if ((DECL_OVERLOADED_OPERATOR_P (current_function_decl) == NEW_EXPR 6860 || DECL_OVERLOADED_OPERATOR_P (current_function_decl) == VEC_NEW_EXPR) 6861 && !TYPE_NOTHROW_P (TREE_TYPE (current_function_decl)) 6862 && ! flag_check_new 6863 && null_ptr_cst_p (retval)) 6864 warning (0, "%<operator new%> must not return NULL unless it is " 6865 "declared %<throw()%> (or -fcheck-new is in effect)"); 6866 6867 /* Effective C++ rule 15. See also start_function. */ 6868 if (warn_ecpp 6869 && DECL_NAME (current_function_decl) == ansi_assopname(NOP_EXPR)) 6870 { 6871 bool warn = true; 6872 6873 /* The function return type must be a reference to the current 6874 class. */ 6875 if (TREE_CODE (valtype) == REFERENCE_TYPE 6876 && same_type_ignoring_top_level_qualifiers_p 6877 (TREE_TYPE (valtype), TREE_TYPE (current_class_ref))) 6878 { 6879 /* Returning '*this' is obviously OK. */ 6880 if (retval == current_class_ref) 6881 warn = false; 6882 /* If we are calling a function whose return type is the same of 6883 the current class reference, it is ok. */ 6884 else if (TREE_CODE (retval) == INDIRECT_REF 6885 && TREE_CODE (TREE_OPERAND (retval, 0)) == CALL_EXPR) 6886 warn = false; 6887 } 6888 6889 if (warn) 6890 warning (OPT_Weffc__, "%<operator=%> should return a reference to %<*this%>"); 6891 } 6892 6893 /* The fabled Named Return Value optimization, as per [class.copy]/15: 6894 6895 [...] For a function with a class return type, if the expression 6896 in the return statement is the name of a local object, and the cv- 6897 unqualified type of the local object is the same as the function 6898 return type, an implementation is permitted to omit creating the tem- 6899 porary object to hold the function return value [...] 6900 6901 So, if this is a value-returning function that always returns the same 6902 local variable, remember it. 6903 6904 It might be nice to be more flexible, and choose the first suitable 6905 variable even if the function sometimes returns something else, but 6906 then we run the risk of clobbering the variable we chose if the other 6907 returned expression uses the chosen variable somehow. And people expect 6908 this restriction, anyway. (jason 2000-11-19) 6909 6910 See finish_function and finalize_nrv for the rest of this optimization. */ 6911 6912 if (fn_returns_value_p && flag_elide_constructors) 6913 { 6914 if (retval != NULL_TREE 6915 && (current_function_return_value == NULL_TREE 6916 || current_function_return_value == retval) 6917 && TREE_CODE (retval) == VAR_DECL 6918 && DECL_CONTEXT (retval) == current_function_decl 6919 && ! TREE_STATIC (retval) 6920 && ! DECL_ANON_UNION_VAR_P (retval) 6921 && (DECL_ALIGN (retval) 6922 >= DECL_ALIGN (DECL_RESULT (current_function_decl))) 6923 && same_type_p ((TYPE_MAIN_VARIANT 6924 (TREE_TYPE (retval))), 6925 (TYPE_MAIN_VARIANT 6926 (TREE_TYPE (TREE_TYPE (current_function_decl)))))) 6927 current_function_return_value = retval; 6928 else 6929 current_function_return_value = error_mark_node; 6930 } 6931 6932 /* We don't need to do any conversions when there's nothing being 6933 returned. */ 6934 if (!retval) 6935 return NULL_TREE; 6936 6937 /* Do any required conversions. */ 6938 if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl)) 6939 /* No conversions are required. */ 6940 ; 6941 else 6942 { 6943 /* The type the function is declared to return. */ 6944 tree functype = TREE_TYPE (TREE_TYPE (current_function_decl)); 6945 6946 /* The functype's return type will have been set to void, if it 6947 was an incomplete type. Just treat this as 'return;' */ 6948 if (VOID_TYPE_P (functype)) 6949 return error_mark_node; 6950 6951 /* First convert the value to the function's return type, then 6952 to the type of return value's location to handle the 6953 case that functype is smaller than the valtype. */ 6954 retval = convert_for_initialization 6955 (NULL_TREE, functype, retval, LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING, 6956 "return", NULL_TREE, 0); 6957 retval = convert (valtype, retval); 6958 6959 /* If the conversion failed, treat this just like `return;'. */ 6960 if (retval == error_mark_node) 6961 return retval; 6962 /* We can't initialize a register from a AGGR_INIT_EXPR. */ 6963 else if (! current_function_returns_struct 6964 && TREE_CODE (retval) == TARGET_EXPR 6965 && TREE_CODE (TREE_OPERAND (retval, 1)) == AGGR_INIT_EXPR) 6966 retval = build2 (COMPOUND_EXPR, TREE_TYPE (retval), retval, 6967 TREE_OPERAND (retval, 0)); 6968 else 6969 maybe_warn_about_returning_address_of_local (retval); 6970 } 6971 6972 /* Actually copy the value returned into the appropriate location. */ 6973 if (retval && retval != result) 6974 retval = build2 (INIT_EXPR, TREE_TYPE (result), result, retval); 6975 6976 return retval; 6977} 6978 6979 6980/* Returns nonzero if the pointer-type FROM can be converted to the 6981 pointer-type TO via a qualification conversion. If CONSTP is -1, 6982 then we return nonzero if the pointers are similar, and the 6983 cv-qualification signature of FROM is a proper subset of that of TO. 6984 6985 If CONSTP is positive, then all outer pointers have been 6986 const-qualified. */ 6987 6988static int 6989comp_ptr_ttypes_real (tree to, tree from, int constp) 6990{ 6991 bool to_more_cv_qualified = false; 6992 6993 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 6994 { 6995 if (TREE_CODE (to) != TREE_CODE (from)) 6996 return 0; 6997 6998 if (TREE_CODE (from) == OFFSET_TYPE 6999 && !same_type_p (TYPE_OFFSET_BASETYPE (from), 7000 TYPE_OFFSET_BASETYPE (to))) 7001 return 0; 7002 7003 /* Const and volatile mean something different for function types, 7004 so the usual checks are not appropriate. */ 7005 if (TREE_CODE (to) != FUNCTION_TYPE && TREE_CODE (to) != METHOD_TYPE) 7006 { 7007 /* In Objective-C++, some types may have been 'volatilized' by 7008 the compiler for EH; when comparing them here, the volatile 7009 qualification must be ignored. */ 7010 bool objc_quals_match = objc_type_quals_match (to, from); 7011 7012 if (!at_least_as_qualified_p (to, from) && !objc_quals_match) 7013 return 0; 7014 7015 if (!at_least_as_qualified_p (from, to) && !objc_quals_match) 7016 { 7017 if (constp == 0) 7018 return 0; 7019 to_more_cv_qualified = true; 7020 } 7021 7022 if (constp > 0) 7023 constp &= TYPE_READONLY (to); 7024 } 7025 7026 if (TREE_CODE (to) != POINTER_TYPE && !TYPE_PTRMEM_P (to)) 7027 return ((constp >= 0 || to_more_cv_qualified) 7028 && same_type_ignoring_top_level_qualifiers_p (to, from)); 7029 } 7030} 7031 7032/* When comparing, say, char ** to char const **, this function takes 7033 the 'char *' and 'char const *'. Do not pass non-pointer/reference 7034 types to this function. */ 7035 7036int 7037comp_ptr_ttypes (tree to, tree from) 7038{ 7039 return comp_ptr_ttypes_real (to, from, 1); 7040} 7041 7042/* Returns 1 if to and from are (possibly multi-level) pointers to the same 7043 type or inheritance-related types, regardless of cv-quals. */ 7044 7045int 7046ptr_reasonably_similar (tree to, tree from) 7047{ 7048 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 7049 { 7050 /* Any target type is similar enough to void. */ 7051 if (TREE_CODE (to) == VOID_TYPE 7052 || TREE_CODE (from) == VOID_TYPE) 7053 return 1; 7054 7055 if (TREE_CODE (to) != TREE_CODE (from)) 7056 return 0; 7057 7058 if (TREE_CODE (from) == OFFSET_TYPE 7059 && comptypes (TYPE_OFFSET_BASETYPE (to), 7060 TYPE_OFFSET_BASETYPE (from), 7061 COMPARE_BASE | COMPARE_DERIVED)) 7062 continue; 7063 7064 if (TREE_CODE (to) == VECTOR_TYPE 7065 && vector_types_convertible_p (to, from, false)) 7066 return 1; 7067 7068 if (TREE_CODE (to) == INTEGER_TYPE 7069 && TYPE_PRECISION (to) == TYPE_PRECISION (from)) 7070 return 1; 7071 7072 if (TREE_CODE (to) == FUNCTION_TYPE) 7073 return 1; 7074 7075 if (TREE_CODE (to) != POINTER_TYPE) 7076 return comptypes 7077 (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from), 7078 COMPARE_BASE | COMPARE_DERIVED); 7079 } 7080} 7081 7082/* Return true if TO and FROM (both of which are POINTER_TYPEs or 7083 pointer-to-member types) are the same, ignoring cv-qualification at 7084 all levels. */ 7085 7086bool 7087comp_ptr_ttypes_const (tree to, tree from) 7088{ 7089 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 7090 { 7091 if (TREE_CODE (to) != TREE_CODE (from)) 7092 return false; 7093 7094 if (TREE_CODE (from) == OFFSET_TYPE 7095 && same_type_p (TYPE_OFFSET_BASETYPE (from), 7096 TYPE_OFFSET_BASETYPE (to))) 7097 continue; 7098 7099 if (TREE_CODE (to) != POINTER_TYPE) 7100 return same_type_ignoring_top_level_qualifiers_p (to, from); 7101 } 7102} 7103 7104/* Returns the type qualifiers for this type, including the qualifiers on the 7105 elements for an array type. */ 7106 7107int 7108cp_type_quals (tree type) 7109{ 7110 type = strip_array_types (type); 7111 if (type == error_mark_node) 7112 return TYPE_UNQUALIFIED; 7113 return TYPE_QUALS (type); 7114} 7115 7116/* Returns nonzero if the TYPE is const from a C++ perspective: look inside 7117 arrays. */ 7118 7119bool 7120cp_type_readonly (tree type) 7121{ 7122 type = strip_array_types (type); 7123 return TYPE_READONLY (type); 7124} 7125 7126/* Returns nonzero if the TYPE contains a mutable member. */ 7127 7128bool 7129cp_has_mutable_p (tree type) 7130{ 7131 type = strip_array_types (type); 7132 7133 return CLASS_TYPE_P (type) && CLASSTYPE_HAS_MUTABLE (type); 7134} 7135 7136/* Apply the TYPE_QUALS to the new DECL. */ 7137void 7138cp_apply_type_quals_to_decl (int type_quals, tree decl) 7139{ 7140 tree type = TREE_TYPE (decl); 7141 7142 if (type == error_mark_node) 7143 return; 7144 7145 if (TREE_CODE (type) == FUNCTION_TYPE 7146 && type_quals != TYPE_UNQUALIFIED) 7147 { 7148 /* This was an error in C++98 (cv-qualifiers cannot be added to 7149 a function type), but DR 295 makes the code well-formed by 7150 dropping the extra qualifiers. */ 7151 if (pedantic) 7152 { 7153 tree bad_type = build_qualified_type (type, type_quals); 7154 pedwarn ("ignoring %qV qualifiers added to function type %qT", 7155 bad_type, type); 7156 } 7157 7158 TREE_TYPE (decl) = TYPE_MAIN_VARIANT (type); 7159 return; 7160 } 7161 7162 /* Avoid setting TREE_READONLY incorrectly. */ 7163 if (/* If the object has a constructor, the constructor may modify 7164 the object. */ 7165 TYPE_NEEDS_CONSTRUCTING (type) 7166 /* If the type isn't complete, we don't know yet if it will need 7167 constructing. */ 7168 || !COMPLETE_TYPE_P (type) 7169 /* If the type has a mutable component, that component might be 7170 modified. */ 7171 || TYPE_HAS_MUTABLE_P (type)) 7172 type_quals &= ~TYPE_QUAL_CONST; 7173 7174 c_apply_type_quals_to_decl (type_quals, decl); 7175} 7176 7177/* Subroutine of casts_away_constness. Make T1 and T2 point at 7178 exemplar types such that casting T1 to T2 is casting away constness 7179 if and only if there is no implicit conversion from T1 to T2. */ 7180 7181static void 7182casts_away_constness_r (tree *t1, tree *t2) 7183{ 7184 int quals1; 7185 int quals2; 7186 7187 /* [expr.const.cast] 7188 7189 For multi-level pointer to members and multi-level mixed pointers 7190 and pointers to members (conv.qual), the "member" aspect of a 7191 pointer to member level is ignored when determining if a const 7192 cv-qualifier has been cast away. */ 7193 /* [expr.const.cast] 7194 7195 For two pointer types: 7196 7197 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type 7198 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type 7199 K is min(N,M) 7200 7201 casting from X1 to X2 casts away constness if, for a non-pointer 7202 type T there does not exist an implicit conversion (clause 7203 _conv_) from: 7204 7205 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N * 7206 7207 to 7208 7209 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */ 7210 if ((!TYPE_PTR_P (*t1) && !TYPE_PTRMEM_P (*t1)) 7211 || (!TYPE_PTR_P (*t2) && !TYPE_PTRMEM_P (*t2))) 7212 { 7213 *t1 = cp_build_qualified_type (void_type_node, 7214 cp_type_quals (*t1)); 7215 *t2 = cp_build_qualified_type (void_type_node, 7216 cp_type_quals (*t2)); 7217 return; 7218 } 7219 7220 quals1 = cp_type_quals (*t1); 7221 quals2 = cp_type_quals (*t2); 7222 7223 if (TYPE_PTRMEM_P (*t1)) 7224 *t1 = TYPE_PTRMEM_POINTED_TO_TYPE (*t1); 7225 else 7226 *t1 = TREE_TYPE (*t1); 7227 if (TYPE_PTRMEM_P (*t2)) 7228 *t2 = TYPE_PTRMEM_POINTED_TO_TYPE (*t2); 7229 else 7230 *t2 = TREE_TYPE (*t2); 7231 7232 casts_away_constness_r (t1, t2); 7233 *t1 = build_pointer_type (*t1); 7234 *t2 = build_pointer_type (*t2); 7235 *t1 = cp_build_qualified_type (*t1, quals1); 7236 *t2 = cp_build_qualified_type (*t2, quals2); 7237} 7238 7239/* Returns nonzero if casting from TYPE1 to TYPE2 casts away 7240 constness. */ 7241 7242static bool 7243casts_away_constness (tree t1, tree t2) 7244{ 7245 if (TREE_CODE (t2) == REFERENCE_TYPE) 7246 { 7247 /* [expr.const.cast] 7248 7249 Casting from an lvalue of type T1 to an lvalue of type T2 7250 using a reference cast casts away constness if a cast from an 7251 rvalue of type "pointer to T1" to the type "pointer to T2" 7252 casts away constness. */ 7253 t1 = (TREE_CODE (t1) == REFERENCE_TYPE ? TREE_TYPE (t1) : t1); 7254 return casts_away_constness (build_pointer_type (t1), 7255 build_pointer_type (TREE_TYPE (t2))); 7256 } 7257 7258 if (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2)) 7259 /* [expr.const.cast] 7260 7261 Casting from an rvalue of type "pointer to data member of X 7262 of type T1" to the type "pointer to data member of Y of type 7263 T2" casts away constness if a cast from an rvalue of type 7264 "pointer to T1" to the type "pointer to T2" casts away 7265 constness. */ 7266 return casts_away_constness 7267 (build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t1)), 7268 build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t2))); 7269 7270 /* Casting away constness is only something that makes sense for 7271 pointer or reference types. */ 7272 if (TREE_CODE (t1) != POINTER_TYPE 7273 || TREE_CODE (t2) != POINTER_TYPE) 7274 return false; 7275 7276 /* Top-level qualifiers don't matter. */ 7277 t1 = TYPE_MAIN_VARIANT (t1); 7278 t2 = TYPE_MAIN_VARIANT (t2); 7279 casts_away_constness_r (&t1, &t2); 7280 if (!can_convert (t2, t1)) 7281 return true; 7282 7283 return false; 7284} 7285 7286/* If T is a REFERENCE_TYPE return the type to which T refers. 7287 Otherwise, return T itself. */ 7288 7289tree 7290non_reference (tree t) 7291{ 7292 if (TREE_CODE (t) == REFERENCE_TYPE) 7293 t = TREE_TYPE (t); 7294 return t; 7295} 7296 7297 7298/* Return nonzero if REF is an lvalue valid for this language; 7299 otherwise, print an error message and return zero. USE says 7300 how the lvalue is being used and so selects the error message. */ 7301 7302int 7303lvalue_or_else (tree ref, enum lvalue_use use) 7304{ 7305 int win = lvalue_p (ref); 7306 7307 if (!win) 7308 lvalue_error (use); 7309 7310 return win; 7311} 7312