typeck.c revision 146895
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, 59 Temple Place - Suite 330, 21Boston, MA 02111-1307, 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 There are also routines to build RETURN_STMT nodes and CASE_STMT nodes, 30 and to process initializations in declarations (since they work 31 like a strange sort of assignment). */ 32 33#include "config.h" 34#include "system.h" 35#include "coretypes.h" 36#include "tm.h" 37#include "tree.h" 38#include "rtl.h" 39#include "expr.h" 40#include "cp-tree.h" 41#include "tm_p.h" 42#include "flags.h" 43#include "output.h" 44#include "toplev.h" 45#include "diagnostic.h" 46#include "target.h" 47#include "convert.h" 48 49static tree convert_for_assignment (tree, tree, const char *, tree, int); 50static tree cp_pointer_int_sum (enum tree_code, tree, tree); 51static tree rationalize_conditional_expr (enum tree_code, tree); 52static int comp_ptr_ttypes_real (tree, tree, int); 53static int comp_ptr_ttypes_const (tree, tree); 54static bool comp_except_types (tree, tree, bool); 55static bool comp_array_types (tree, tree, bool); 56static tree common_base_type (tree, tree); 57static tree pointer_diff (tree, tree, tree); 58static tree get_delta_difference (tree, tree, int); 59static void casts_away_constness_r (tree *, tree *); 60static bool casts_away_constness (tree, tree); 61static void maybe_warn_about_returning_address_of_local (tree); 62static tree lookup_destructor (tree, tree, tree); 63 64/* Return the target type of TYPE, which means return T for: 65 T*, T&, T[], T (...), and otherwise, just T. */ 66 67tree 68target_type (tree type) 69{ 70 type = non_reference (type); 71 while (TREE_CODE (type) == POINTER_TYPE 72 || TREE_CODE (type) == ARRAY_TYPE 73 || TREE_CODE (type) == FUNCTION_TYPE 74 || TREE_CODE (type) == METHOD_TYPE 75 || TYPE_PTRMEM_P (type)) 76 type = TREE_TYPE (type); 77 return type; 78} 79 80/* Do `exp = require_complete_type (exp);' to make sure exp 81 does not have an incomplete type. (That includes void types.) 82 Returns the error_mark_node if the VALUE does not have 83 complete type when this function returns. */ 84 85tree 86require_complete_type (tree value) 87{ 88 tree type; 89 90 if (processing_template_decl || value == error_mark_node) 91 return value; 92 93 if (TREE_CODE (value) == OVERLOAD) 94 type = unknown_type_node; 95 else 96 type = TREE_TYPE (value); 97 98 /* First, detect a valid value with a complete type. */ 99 if (COMPLETE_TYPE_P (type)) 100 return value; 101 102 if (complete_type_or_else (type, value)) 103 return value; 104 else 105 return error_mark_node; 106} 107 108/* Try to complete TYPE, if it is incomplete. For example, if TYPE is 109 a template instantiation, do the instantiation. Returns TYPE, 110 whether or not it could be completed, unless something goes 111 horribly wrong, in which case the error_mark_node is returned. */ 112 113tree 114complete_type (tree type) 115{ 116 if (type == NULL_TREE) 117 /* Rather than crash, we return something sure to cause an error 118 at some point. */ 119 return error_mark_node; 120 121 if (type == error_mark_node || COMPLETE_TYPE_P (type)) 122 ; 123 else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type)) 124 { 125 tree t = complete_type (TREE_TYPE (type)); 126 if (COMPLETE_TYPE_P (t) && !dependent_type_p (type)) 127 layout_type (type); 128 TYPE_NEEDS_CONSTRUCTING (type) 129 = TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (t)); 130 TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type) 131 = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TYPE_MAIN_VARIANT (t)); 132 } 133 else if (CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INSTANTIATION (type)) 134 instantiate_class_template (TYPE_MAIN_VARIANT (type)); 135 136 return type; 137} 138 139/* Like complete_type, but issue an error if the TYPE cannot be completed. 140 VALUE is used for informative diagnostics. DIAG_TYPE indicates the type 141 of diagnostic: 0 for an error, 1 for a warning, 2 for a pedwarn. 142 Returns NULL_TREE if the type cannot be made complete. */ 143 144tree 145complete_type_or_diagnostic (tree type, tree value, int diag_type) 146{ 147 type = complete_type (type); 148 if (type == error_mark_node) 149 /* We already issued an error. */ 150 return NULL_TREE; 151 else if (!COMPLETE_TYPE_P (type)) 152 { 153 cxx_incomplete_type_diagnostic (value, type, diag_type); 154 return NULL_TREE; 155 } 156 else 157 return type; 158} 159 160/* Return truthvalue of whether type of EXP is instantiated. */ 161 162int 163type_unknown_p (tree exp) 164{ 165 return (TREE_CODE (exp) == TREE_LIST 166 || TREE_TYPE (exp) == unknown_type_node); 167} 168 169 170/* Return the common type of two parameter lists. 171 We assume that comptypes has already been done and returned 1; 172 if that isn't so, this may crash. 173 174 As an optimization, free the space we allocate if the parameter 175 lists are already common. */ 176 177tree 178commonparms (tree p1, tree p2) 179{ 180 tree oldargs = p1, newargs, n; 181 int i, len; 182 int any_change = 0; 183 184 len = list_length (p1); 185 newargs = tree_last (p1); 186 187 if (newargs == void_list_node) 188 i = 1; 189 else 190 { 191 i = 0; 192 newargs = 0; 193 } 194 195 for (; i < len; i++) 196 newargs = tree_cons (NULL_TREE, NULL_TREE, newargs); 197 198 n = newargs; 199 200 for (i = 0; p1; 201 p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n), i++) 202 { 203 if (TREE_PURPOSE (p1) && !TREE_PURPOSE (p2)) 204 { 205 TREE_PURPOSE (n) = TREE_PURPOSE (p1); 206 any_change = 1; 207 } 208 else if (! TREE_PURPOSE (p1)) 209 { 210 if (TREE_PURPOSE (p2)) 211 { 212 TREE_PURPOSE (n) = TREE_PURPOSE (p2); 213 any_change = 1; 214 } 215 } 216 else 217 { 218 if (1 != simple_cst_equal (TREE_PURPOSE (p1), TREE_PURPOSE (p2))) 219 any_change = 1; 220 TREE_PURPOSE (n) = TREE_PURPOSE (p2); 221 } 222 if (TREE_VALUE (p1) != TREE_VALUE (p2)) 223 { 224 any_change = 1; 225 TREE_VALUE (n) = merge_types (TREE_VALUE (p1), TREE_VALUE (p2)); 226 } 227 else 228 TREE_VALUE (n) = TREE_VALUE (p1); 229 } 230 if (! any_change) 231 return oldargs; 232 233 return newargs; 234} 235 236/* Given a type, perhaps copied for a typedef, 237 find the "original" version of it. */ 238tree 239original_type (tree t) 240{ 241 while (TYPE_NAME (t) != NULL_TREE) 242 { 243 tree x = TYPE_NAME (t); 244 if (TREE_CODE (x) != TYPE_DECL) 245 break; 246 x = DECL_ORIGINAL_TYPE (x); 247 if (x == NULL_TREE) 248 break; 249 t = x; 250 } 251 return t; 252} 253 254/* T1 and T2 are arithmetic or enumeration types. Return the type 255 that will result from the "usual arithmetic conversions" on T1 and 256 T2 as described in [expr]. */ 257 258tree 259type_after_usual_arithmetic_conversions (tree t1, tree t2) 260{ 261 enum tree_code code1 = TREE_CODE (t1); 262 enum tree_code code2 = TREE_CODE (t2); 263 tree attributes; 264 265 /* FIXME: Attributes. */ 266 my_friendly_assert (ARITHMETIC_TYPE_P (t1) 267 || TREE_CODE (t1) == COMPLEX_TYPE 268 || TREE_CODE (t1) == ENUMERAL_TYPE, 269 19990725); 270 my_friendly_assert (ARITHMETIC_TYPE_P (t2) 271 || TREE_CODE (t2) == COMPLEX_TYPE 272 || TREE_CODE (t2) == ENUMERAL_TYPE, 273 19990725); 274 275 /* In what follows, we slightly generalize the rules given in [expr] so 276 as to deal with `long long' and `complex'. First, merge the 277 attributes. */ 278 attributes = (*targetm.merge_type_attributes) (t1, t2); 279 280 /* If one type is complex, form the common type of the non-complex 281 components, then make that complex. Use T1 or T2 if it is the 282 required type. */ 283 if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE) 284 { 285 tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1; 286 tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2; 287 tree subtype 288 = type_after_usual_arithmetic_conversions (subtype1, subtype2); 289 290 if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype) 291 return build_type_attribute_variant (t1, attributes); 292 else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype) 293 return build_type_attribute_variant (t2, attributes); 294 else 295 return build_type_attribute_variant (build_complex_type (subtype), 296 attributes); 297 } 298 299 /* If only one is real, use it as the result. */ 300 if (code1 == REAL_TYPE && code2 != REAL_TYPE) 301 return build_type_attribute_variant (t1, attributes); 302 if (code2 == REAL_TYPE && code1 != REAL_TYPE) 303 return build_type_attribute_variant (t2, attributes); 304 305 /* Perform the integral promotions. */ 306 if (code1 != REAL_TYPE) 307 { 308 t1 = type_promotes_to (t1); 309 t2 = type_promotes_to (t2); 310 } 311 312 /* Both real or both integers; use the one with greater precision. */ 313 if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2)) 314 return build_type_attribute_variant (t1, attributes); 315 else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1)) 316 return build_type_attribute_variant (t2, attributes); 317 318 /* The types are the same; no need to do anything fancy. */ 319 if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2)) 320 return build_type_attribute_variant (t1, attributes); 321 322 if (code1 != REAL_TYPE) 323 { 324 /* If one is a sizetype, use it so size_binop doesn't blow up. */ 325 if (TYPE_IS_SIZETYPE (t1) > TYPE_IS_SIZETYPE (t2)) 326 return build_type_attribute_variant (t1, attributes); 327 if (TYPE_IS_SIZETYPE (t2) > TYPE_IS_SIZETYPE (t1)) 328 return build_type_attribute_variant (t2, attributes); 329 330 /* If one is unsigned long long, then convert the other to unsigned 331 long long. */ 332 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_unsigned_type_node) 333 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_unsigned_type_node)) 334 return build_type_attribute_variant (long_long_unsigned_type_node, 335 attributes); 336 /* If one is a long long, and the other is an unsigned long, and 337 long long can represent all the values of an unsigned long, then 338 convert to a long long. Otherwise, convert to an unsigned long 339 long. Otherwise, if either operand is long long, convert the 340 other to long long. 341 342 Since we're here, we know the TYPE_PRECISION is the same; 343 therefore converting to long long cannot represent all the values 344 of an unsigned long, so we choose unsigned long long in that 345 case. */ 346 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_integer_type_node) 347 || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_integer_type_node)) 348 { 349 tree t = ((TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2)) 350 ? long_long_unsigned_type_node 351 : long_long_integer_type_node); 352 return build_type_attribute_variant (t, attributes); 353 } 354 355 /* Go through the same procedure, but for longs. */ 356 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_unsigned_type_node) 357 || same_type_p (TYPE_MAIN_VARIANT (t2), long_unsigned_type_node)) 358 return build_type_attribute_variant (long_unsigned_type_node, 359 attributes); 360 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_integer_type_node) 361 || same_type_p (TYPE_MAIN_VARIANT (t2), long_integer_type_node)) 362 { 363 tree t = ((TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2)) 364 ? long_unsigned_type_node : long_integer_type_node); 365 return build_type_attribute_variant (t, attributes); 366 } 367 /* Otherwise prefer the unsigned one. */ 368 if (TREE_UNSIGNED (t1)) 369 return build_type_attribute_variant (t1, attributes); 370 else 371 return build_type_attribute_variant (t2, attributes); 372 } 373 else 374 { 375 if (same_type_p (TYPE_MAIN_VARIANT (t1), long_double_type_node) 376 || same_type_p (TYPE_MAIN_VARIANT (t2), long_double_type_node)) 377 return build_type_attribute_variant (long_double_type_node, 378 attributes); 379 if (same_type_p (TYPE_MAIN_VARIANT (t1), double_type_node) 380 || same_type_p (TYPE_MAIN_VARIANT (t2), double_type_node)) 381 return build_type_attribute_variant (double_type_node, 382 attributes); 383 if (same_type_p (TYPE_MAIN_VARIANT (t1), float_type_node) 384 || same_type_p (TYPE_MAIN_VARIANT (t2), float_type_node)) 385 return build_type_attribute_variant (float_type_node, 386 attributes); 387 388 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of 389 the standard C++ floating-point types. Logic earlier in this 390 function has already eliminated the possibility that 391 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no 392 compelling reason to choose one or the other. */ 393 return build_type_attribute_variant (t1, attributes); 394 } 395} 396 397/* Subroutine of composite_pointer_type to implement the recursive 398 case. See that function for documentation fo the parameters. */ 399 400static tree 401composite_pointer_type_r (tree t1, tree t2, const char* location) 402{ 403 tree pointee1; 404 tree pointee2; 405 tree result_type; 406 tree attributes; 407 408 /* Determine the types pointed to by T1 and T2. */ 409 if (TREE_CODE (t1) == POINTER_TYPE) 410 { 411 pointee1 = TREE_TYPE (t1); 412 pointee2 = TREE_TYPE (t2); 413 } 414 else 415 { 416 pointee1 = TYPE_PTRMEM_POINTED_TO_TYPE (t1); 417 pointee2 = TYPE_PTRMEM_POINTED_TO_TYPE (t2); 418 } 419 420 /* [expr.rel] 421 422 Otherwise, the composite pointer type is a pointer type 423 similar (_conv.qual_) to the type of one of the operands, 424 with a cv-qualification signature (_conv.qual_) that is the 425 union of the cv-qualification signatures of the operand 426 types. */ 427 if (same_type_ignoring_top_level_qualifiers_p (pointee1, pointee2)) 428 result_type = pointee1; 429 else if ((TREE_CODE (pointee1) == POINTER_TYPE 430 && TREE_CODE (pointee2) == POINTER_TYPE) 431 || (TYPE_PTR_TO_MEMBER_P (pointee1) 432 && TYPE_PTR_TO_MEMBER_P (pointee2))) 433 result_type = composite_pointer_type_r (pointee1, pointee2, location); 434 else 435 { 436 pedwarn ("%s between distinct pointer types `%T' and `%T' " 437 "lacks a cast", 438 location, t1, t2); 439 result_type = void_type_node; 440 } 441 result_type = cp_build_qualified_type (result_type, 442 (cp_type_quals (pointee1) 443 | cp_type_quals (pointee2))); 444 /* If the original types were pointers to members, so is the 445 result. */ 446 if (TYPE_PTR_TO_MEMBER_P (t1)) 447 { 448 if (!same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1), 449 TYPE_PTRMEM_CLASS_TYPE (t2))) 450 pedwarn ("%s between distinct pointer types `%T' and `%T' " 451 "lacks a cast", 452 location, t1, t2); 453 result_type = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1), 454 result_type); 455 } 456 else 457 result_type = build_pointer_type (result_type); 458 459 /* Merge the attributes. */ 460 attributes = (*targetm.merge_type_attributes) (t1, t2); 461 return build_type_attribute_variant (result_type, attributes); 462} 463 464/* Return the composite pointer type (see [expr.rel]) for T1 and T2. 465 ARG1 and ARG2 are the values with those types. The LOCATION is a 466 string describing the current location, in case an error occurs. 467 468 This routine also implements the computation of a common type for 469 pointers-to-members as per [expr.eq]. */ 470 471tree 472composite_pointer_type (tree t1, tree t2, tree arg1, tree arg2, 473 const char* location) 474{ 475 tree class1; 476 tree class2; 477 478 /* [expr.rel] 479 480 If one operand is a null pointer constant, the composite pointer 481 type is the type of the other operand. */ 482 if (null_ptr_cst_p (arg1)) 483 return t2; 484 if (null_ptr_cst_p (arg2)) 485 return t1; 486 487 /* We have: 488 489 [expr.rel] 490 491 If one of the operands has type "pointer to cv1 void*", then 492 the other has type "pointer to cv2T", and the composite pointer 493 type is "pointer to cv12 void", where cv12 is the union of cv1 494 and cv2. 495 496 If either type is a pointer to void, make sure it is T1. */ 497 if (TREE_CODE (t2) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t2))) 498 { 499 tree t; 500 t = t1; 501 t1 = t2; 502 t2 = t; 503 } 504 505 /* Now, if T1 is a pointer to void, merge the qualifiers. */ 506 if (TREE_CODE (t1) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t1))) 507 { 508 tree attributes; 509 tree result_type; 510 511 if (pedantic && TYPE_PTRFN_P (t2)) 512 pedwarn ("ISO C++ forbids %s between pointer of type `void *' and pointer-to-function", location); 513 result_type 514 = cp_build_qualified_type (void_type_node, 515 (cp_type_quals (TREE_TYPE (t1)) 516 | cp_type_quals (TREE_TYPE (t2)))); 517 result_type = build_pointer_type (result_type); 518 /* Merge the attributes. */ 519 attributes = (*targetm.merge_type_attributes) (t1, t2); 520 return build_type_attribute_variant (result_type, attributes); 521 } 522 523 /* [expr.eq] permits the application of a pointer conversion to 524 bring the pointers to a common type. */ 525 if (TREE_CODE (t1) == POINTER_TYPE && TREE_CODE (t2) == POINTER_TYPE 526 && CLASS_TYPE_P (TREE_TYPE (t1)) 527 && CLASS_TYPE_P (TREE_TYPE (t2)) 528 && !same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (t1), 529 TREE_TYPE (t2))) 530 { 531 class1 = TREE_TYPE (t1); 532 class2 = TREE_TYPE (t2); 533 534 if (DERIVED_FROM_P (class1, class2)) 535 t2 = (build_pointer_type 536 (cp_build_qualified_type (class1, TYPE_QUALS (class2)))); 537 else if (DERIVED_FROM_P (class2, class1)) 538 t1 = (build_pointer_type 539 (cp_build_qualified_type (class2, TYPE_QUALS (class1)))); 540 else 541 { 542 error ("%s between distinct pointer types `%T' and `%T' " 543 "lacks a cast", location, t1, t2); 544 return error_mark_node; 545 } 546 } 547 /* [expr.eq] permits the application of a pointer-to-member 548 conversion to change the class type of one of the types. */ 549 else if (TYPE_PTR_TO_MEMBER_P (t1) 550 && !same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1), 551 TYPE_PTRMEM_CLASS_TYPE (t2))) 552 { 553 class1 = TYPE_PTRMEM_CLASS_TYPE (t1); 554 class2 = TYPE_PTRMEM_CLASS_TYPE (t2); 555 556 if (DERIVED_FROM_P (class1, class2)) 557 t1 = build_ptrmem_type (class2, TYPE_PTRMEM_POINTED_TO_TYPE (t1)); 558 else if (DERIVED_FROM_P (class2, class1)) 559 t2 = build_ptrmem_type (class1, TYPE_PTRMEM_POINTED_TO_TYPE (t2)); 560 else 561 { 562 error ("%s between distinct pointer-to-member types `%T' and `%T' " 563 "lacks a cast", location, t1, t2); 564 return error_mark_node; 565 } 566 } 567 568 return composite_pointer_type_r (t1, t2, location); 569} 570 571/* Return the merged type of two types. 572 We assume that comptypes has already been done and returned 1; 573 if that isn't so, this may crash. 574 575 This just combines attributes and default arguments; any other 576 differences would cause the two types to compare unalike. */ 577 578tree 579merge_types (tree t1, tree t2) 580{ 581 enum tree_code code1; 582 enum tree_code code2; 583 tree attributes; 584 585 /* Save time if the two types are the same. */ 586 if (t1 == t2) 587 return t1; 588 if (original_type (t1) == original_type (t2)) 589 return t1; 590 591 /* If one type is nonsense, use the other. */ 592 if (t1 == error_mark_node) 593 return t2; 594 if (t2 == error_mark_node) 595 return t1; 596 597 /* Merge the attributes. */ 598 attributes = (*targetm.merge_type_attributes) (t1, t2); 599 600 if (TYPE_PTRMEMFUNC_P (t1)) 601 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1); 602 if (TYPE_PTRMEMFUNC_P (t2)) 603 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2); 604 605 code1 = TREE_CODE (t1); 606 code2 = TREE_CODE (t2); 607 608 switch (code1) 609 { 610 case POINTER_TYPE: 611 case REFERENCE_TYPE: 612 /* For two pointers, do this recursively on the target type. */ 613 { 614 tree target = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 615 int quals = cp_type_quals (t1); 616 617 if (code1 == POINTER_TYPE) 618 t1 = build_pointer_type (target); 619 else 620 t1 = build_reference_type (target); 621 t1 = build_type_attribute_variant (t1, attributes); 622 t1 = cp_build_qualified_type (t1, quals); 623 624 if (TREE_CODE (target) == METHOD_TYPE) 625 t1 = build_ptrmemfunc_type (t1); 626 627 return t1; 628 } 629 630 case OFFSET_TYPE: 631 { 632 int quals; 633 tree pointee; 634 quals = cp_type_quals (t1); 635 pointee = merge_types (TYPE_PTRMEM_POINTED_TO_TYPE (t1), 636 TYPE_PTRMEM_POINTED_TO_TYPE (t2)); 637 t1 = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1), 638 pointee); 639 t1 = cp_build_qualified_type (t1, quals); 640 break; 641 } 642 643 case ARRAY_TYPE: 644 { 645 tree elt = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 646 /* Save space: see if the result is identical to one of the args. */ 647 if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1)) 648 return build_type_attribute_variant (t1, attributes); 649 if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2)) 650 return build_type_attribute_variant (t2, attributes); 651 /* Merge the element types, and have a size if either arg has one. */ 652 t1 = build_cplus_array_type 653 (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2)); 654 break; 655 } 656 657 case FUNCTION_TYPE: 658 /* Function types: prefer the one that specified arg types. 659 If both do, merge the arg types. Also merge the return types. */ 660 { 661 tree valtype = merge_types (TREE_TYPE (t1), TREE_TYPE (t2)); 662 tree p1 = TYPE_ARG_TYPES (t1); 663 tree p2 = TYPE_ARG_TYPES (t2); 664 tree rval, raises; 665 666 /* Save space: see if the result is identical to one of the args. */ 667 if (valtype == TREE_TYPE (t1) && ! p2) 668 return cp_build_type_attribute_variant (t1, attributes); 669 if (valtype == TREE_TYPE (t2) && ! p1) 670 return cp_build_type_attribute_variant (t2, attributes); 671 672 /* Simple way if one arg fails to specify argument types. */ 673 if (p1 == NULL_TREE || TREE_VALUE (p1) == void_type_node) 674 { 675 rval = build_function_type (valtype, p2); 676 if ((raises = TYPE_RAISES_EXCEPTIONS (t2))) 677 rval = build_exception_variant (rval, raises); 678 return cp_build_type_attribute_variant (rval, attributes); 679 } 680 raises = TYPE_RAISES_EXCEPTIONS (t1); 681 if (p2 == NULL_TREE || TREE_VALUE (p2) == void_type_node) 682 { 683 rval = build_function_type (valtype, p1); 684 if (raises) 685 rval = build_exception_variant (rval, raises); 686 return cp_build_type_attribute_variant (rval, attributes); 687 } 688 689 rval = build_function_type (valtype, commonparms (p1, p2)); 690 t1 = build_exception_variant (rval, raises); 691 break; 692 } 693 694 case METHOD_TYPE: 695 { 696 /* Get this value the long way, since TYPE_METHOD_BASETYPE 697 is just the main variant of this. */ 698 tree basetype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t2))); 699 tree raises = TYPE_RAISES_EXCEPTIONS (t1); 700 tree t3; 701 702 /* If this was a member function type, get back to the 703 original type of type member function (i.e., without 704 the class instance variable up front. */ 705 t1 = build_function_type (TREE_TYPE (t1), 706 TREE_CHAIN (TYPE_ARG_TYPES (t1))); 707 t2 = build_function_type (TREE_TYPE (t2), 708 TREE_CHAIN (TYPE_ARG_TYPES (t2))); 709 t3 = merge_types (t1, t2); 710 t3 = build_method_type_directly (basetype, TREE_TYPE (t3), 711 TYPE_ARG_TYPES (t3)); 712 t1 = build_exception_variant (t3, raises); 713 break; 714 } 715 716 case TYPENAME_TYPE: 717 /* There is no need to merge attributes into a TYPENAME_TYPE. 718 When the type is instantiated it will have whatever 719 attributes result from the instantiation. */ 720 return t1; 721 722 default:; 723 } 724 return cp_build_type_attribute_variant (t1, attributes); 725} 726 727/* Return the common type of two types. 728 We assume that comptypes has already been done and returned 1; 729 if that isn't so, this may crash. 730 731 This is the type for the result of most arithmetic operations 732 if the operands have the given two types. */ 733 734tree 735common_type (tree t1, tree t2) 736{ 737 enum tree_code code1; 738 enum tree_code code2; 739 740 /* If one type is nonsense, bail. */ 741 if (t1 == error_mark_node || t2 == error_mark_node) 742 return error_mark_node; 743 744 code1 = TREE_CODE (t1); 745 code2 = TREE_CODE (t2); 746 747 if ((ARITHMETIC_TYPE_P (t1) || code1 == ENUMERAL_TYPE 748 || code1 == COMPLEX_TYPE) 749 && (ARITHMETIC_TYPE_P (t2) || code2 == ENUMERAL_TYPE 750 || code2 == COMPLEX_TYPE)) 751 return type_after_usual_arithmetic_conversions (t1, t2); 752 753 else if ((TYPE_PTR_P (t1) && TYPE_PTR_P (t2)) 754 || (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2)) 755 || (TYPE_PTRMEMFUNC_P (t1) && TYPE_PTRMEMFUNC_P (t2))) 756 return composite_pointer_type (t1, t2, error_mark_node, error_mark_node, 757 "conversion"); 758 else 759 abort (); 760} 761 762/* Compare two exception specifier types for exactness or subsetness, if 763 allowed. Returns false for mismatch, true for match (same, or 764 derived and !exact). 765 766 [except.spec] "If a class X ... objects of class X or any class publicly 767 and unambiguously derived from X. Similarly, if a pointer type Y * ... 768 exceptions of type Y * or that are pointers to any type publicly and 769 unambiguously derived from Y. Otherwise a function only allows exceptions 770 that have the same type ..." 771 This does not mention cv qualifiers and is different to what throw 772 [except.throw] and catch [except.catch] will do. They will ignore the 773 top level cv qualifiers, and allow qualifiers in the pointer to class 774 example. 775 776 We implement the letter of the standard. */ 777 778static bool 779comp_except_types (tree a, tree b, bool exact) 780{ 781 if (same_type_p (a, b)) 782 return true; 783 else if (!exact) 784 { 785 if (cp_type_quals (a) || cp_type_quals (b)) 786 return false; 787 788 if (TREE_CODE (a) == POINTER_TYPE 789 && TREE_CODE (b) == POINTER_TYPE) 790 { 791 a = TREE_TYPE (a); 792 b = TREE_TYPE (b); 793 if (cp_type_quals (a) || cp_type_quals (b)) 794 return false; 795 } 796 797 if (TREE_CODE (a) != RECORD_TYPE 798 || TREE_CODE (b) != RECORD_TYPE) 799 return false; 800 801 if (ACCESSIBLY_UNIQUELY_DERIVED_P (a, b)) 802 return true; 803 } 804 return false; 805} 806 807/* Return true if TYPE1 and TYPE2 are equivalent exception specifiers. 808 If EXACT is false, T2 can be stricter than T1 (according to 15.4/7), 809 otherwise it must be exact. Exception lists are unordered, but 810 we've already filtered out duplicates. Most lists will be in order, 811 we should try to make use of that. */ 812 813bool 814comp_except_specs (tree t1, tree t2, bool exact) 815{ 816 tree probe; 817 tree base; 818 int length = 0; 819 820 if (t1 == t2) 821 return true; 822 823 if (t1 == NULL_TREE) /* T1 is ... */ 824 return t2 == NULL_TREE || !exact; 825 if (!TREE_VALUE (t1)) /* t1 is EMPTY */ 826 return t2 != NULL_TREE && !TREE_VALUE (t2); 827 if (t2 == NULL_TREE) /* T2 is ... */ 828 return false; 829 if (TREE_VALUE (t1) && !TREE_VALUE (t2)) /* T2 is EMPTY, T1 is not */ 830 return !exact; 831 832 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1. 833 Count how many we find, to determine exactness. For exact matching and 834 ordered T1, T2, this is an O(n) operation, otherwise its worst case is 835 O(nm). */ 836 for (base = t1; t2 != NULL_TREE; t2 = TREE_CHAIN (t2)) 837 { 838 for (probe = base; probe != NULL_TREE; probe = TREE_CHAIN (probe)) 839 { 840 tree a = TREE_VALUE (probe); 841 tree b = TREE_VALUE (t2); 842 843 if (comp_except_types (a, b, exact)) 844 { 845 if (probe == base && exact) 846 base = TREE_CHAIN (probe); 847 length++; 848 break; 849 } 850 } 851 if (probe == NULL_TREE) 852 return false; 853 } 854 return !exact || base == NULL_TREE || length == list_length (t1); 855} 856 857/* Compare the array types T1 and T2. ALLOW_REDECLARATION is true if 858 [] can match [size]. */ 859 860static bool 861comp_array_types (tree t1, tree t2, bool allow_redeclaration) 862{ 863 tree d1; 864 tree d2; 865 tree max1, max2; 866 867 if (t1 == t2) 868 return true; 869 870 /* The type of the array elements must be the same. */ 871 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 872 return false; 873 874 d1 = TYPE_DOMAIN (t1); 875 d2 = TYPE_DOMAIN (t2); 876 877 if (d1 == d2) 878 return true; 879 880 /* If one of the arrays is dimensionless, and the other has a 881 dimension, they are of different types. However, it is valid to 882 write: 883 884 extern int a[]; 885 int a[3]; 886 887 by [basic.link]: 888 889 declarations for an array object can specify 890 array types that differ by the presence or absence of a major 891 array bound (_dcl.array_). */ 892 if (!d1 || !d2) 893 return allow_redeclaration; 894 895 /* Check that the dimensions are the same. */ 896 897 if (!cp_tree_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))) 898 return false; 899 max1 = TYPE_MAX_VALUE (d1); 900 max2 = TYPE_MAX_VALUE (d2); 901 if (processing_template_decl && !abi_version_at_least (2) 902 && !value_dependent_expression_p (max1) 903 && !value_dependent_expression_p (max2)) 904 { 905 /* With abi-1 we do not fold non-dependent array bounds, (and 906 consequently mangle them incorrectly). We must therefore 907 fold them here, to verify the domains have the same 908 value. */ 909 max1 = fold (max1); 910 max2 = fold (max2); 911 } 912 913 if (!cp_tree_equal (max1, max2)) 914 return false; 915 916 return true; 917} 918 919/* Return true if T1 and T2 are related as allowed by STRICT. STRICT 920 is a bitwise-or of the COMPARE_* flags. */ 921 922bool 923comptypes (tree t1, tree t2, int strict) 924{ 925 if (t1 == t2) 926 return true; 927 928 /* Suppress errors caused by previously reported errors. */ 929 if (t1 == error_mark_node || t2 == error_mark_node) 930 return false; 931 932 my_friendly_assert (TYPE_P (t1) && TYPE_P (t2), 20030623); 933 934 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the 935 current instantiation. */ 936 if (TREE_CODE (t1) == TYPENAME_TYPE) 937 { 938 tree resolved = resolve_typename_type (t1, /*only_current_p=*/true); 939 940 if (resolved != error_mark_node) 941 t1 = resolved; 942 } 943 944 if (TREE_CODE (t2) == TYPENAME_TYPE) 945 { 946 tree resolved = resolve_typename_type (t2, /*only_current_p=*/true); 947 948 if (resolved != error_mark_node) 949 t2 = resolved; 950 } 951 952 /* If either type is the internal version of sizetype, use the 953 language version. */ 954 if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1) 955 && TYPE_DOMAIN (t1)) 956 t1 = TYPE_DOMAIN (t1); 957 958 if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2) 959 && TYPE_DOMAIN (t2)) 960 t2 = TYPE_DOMAIN (t2); 961 962 if (TYPE_PTRMEMFUNC_P (t1)) 963 t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1); 964 if (TYPE_PTRMEMFUNC_P (t2)) 965 t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2); 966 967 /* Different classes of types can't be compatible. */ 968 if (TREE_CODE (t1) != TREE_CODE (t2)) 969 return false; 970 971 /* Qualifiers must match. For array types, we will check when we 972 recur on the array element types. */ 973 if (TREE_CODE (t1) != ARRAY_TYPE 974 && TYPE_QUALS (t1) != TYPE_QUALS (t2)) 975 return false; 976 if (TYPE_FOR_JAVA (t1) != TYPE_FOR_JAVA (t2)) 977 return false; 978 979 /* Allow for two different type nodes which have essentially the same 980 definition. Note that we already checked for equality of the type 981 qualifiers (just above). */ 982 983 if (TREE_CODE (t1) != ARRAY_TYPE 984 && TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2)) 985 return true; 986 987 if (!(*targetm.comp_type_attributes) (t1, t2)) 988 return false; 989 990 switch (TREE_CODE (t1)) 991 { 992 case TEMPLATE_TEMPLATE_PARM: 993 case BOUND_TEMPLATE_TEMPLATE_PARM: 994 if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2) 995 || TEMPLATE_TYPE_LEVEL (t1) != TEMPLATE_TYPE_LEVEL (t2)) 996 return false; 997 if (!comp_template_parms 998 (DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t1)), 999 DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t2)))) 1000 return false; 1001 if (TREE_CODE (t1) == TEMPLATE_TEMPLATE_PARM) 1002 return true; 1003 /* Don't check inheritance. */ 1004 strict = COMPARE_STRICT; 1005 /* Fall through. */ 1006 1007 case RECORD_TYPE: 1008 case UNION_TYPE: 1009 if (TYPE_TEMPLATE_INFO (t1) && TYPE_TEMPLATE_INFO (t2) 1010 && (TYPE_TI_TEMPLATE (t1) == TYPE_TI_TEMPLATE (t2) 1011 || TREE_CODE (t1) == BOUND_TEMPLATE_TEMPLATE_PARM) 1012 && comp_template_args (TYPE_TI_ARGS (t1), TYPE_TI_ARGS (t2))) 1013 return true; 1014 1015 if ((strict & COMPARE_BASE) && DERIVED_FROM_P (t1, t2)) 1016 return true; 1017 else if ((strict & COMPARE_DERIVED) && DERIVED_FROM_P (t2, t1)) 1018 return true; 1019 1020 return false; 1021 1022 case OFFSET_TYPE: 1023 if (!comptypes (TYPE_OFFSET_BASETYPE (t1), TYPE_OFFSET_BASETYPE (t2), 1024 strict & ~COMPARE_REDECLARATION)) 1025 return false; 1026 /* Fall through. */ 1027 1028 case POINTER_TYPE: 1029 case REFERENCE_TYPE: 1030 return same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)); 1031 1032 case METHOD_TYPE: 1033 case FUNCTION_TYPE: 1034 if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))) 1035 return false; 1036 return compparms (TYPE_ARG_TYPES (t1), TYPE_ARG_TYPES (t2)); 1037 1038 case ARRAY_TYPE: 1039 /* Target types must match incl. qualifiers. */ 1040 return comp_array_types (t1, t2, !!(strict & COMPARE_REDECLARATION)); 1041 1042 case TEMPLATE_TYPE_PARM: 1043 return (TEMPLATE_TYPE_IDX (t1) == TEMPLATE_TYPE_IDX (t2) 1044 && TEMPLATE_TYPE_LEVEL (t1) == TEMPLATE_TYPE_LEVEL (t2)); 1045 1046 case TYPENAME_TYPE: 1047 if (!cp_tree_equal (TYPENAME_TYPE_FULLNAME (t1), 1048 TYPENAME_TYPE_FULLNAME (t2))) 1049 return false; 1050 return same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2)); 1051 1052 case UNBOUND_CLASS_TEMPLATE: 1053 if (!cp_tree_equal (TYPE_IDENTIFIER (t1), TYPE_IDENTIFIER (t2))) 1054 return false; 1055 return same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2)); 1056 1057 case COMPLEX_TYPE: 1058 return same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)); 1059 1060 default: 1061 break; 1062 } 1063 return false; 1064} 1065 1066/* Returns 1 if TYPE1 is at least as qualified as TYPE2. */ 1067 1068bool 1069at_least_as_qualified_p (tree type1, tree type2) 1070{ 1071 int q1 = cp_type_quals (type1); 1072 int q2 = cp_type_quals (type2); 1073 1074 /* All qualifiers for TYPE2 must also appear in TYPE1. */ 1075 return (q1 & q2) == q2; 1076} 1077 1078/* Returns 1 if TYPE1 is more qualified than TYPE2. */ 1079 1080bool 1081more_qualified_p (tree type1, tree type2) 1082{ 1083 int q1 = cp_type_quals (type1); 1084 int q2 = cp_type_quals (type2); 1085 1086 return q1 != q2 && (q1 & q2) == q2; 1087} 1088 1089/* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is 1090 more cv-qualified that TYPE1, and 0 otherwise. */ 1091 1092int 1093comp_cv_qualification (tree type1, tree type2) 1094{ 1095 int q1 = cp_type_quals (type1); 1096 int q2 = cp_type_quals (type2); 1097 1098 if (q1 == q2) 1099 return 0; 1100 1101 if ((q1 & q2) == q2) 1102 return 1; 1103 else if ((q1 & q2) == q1) 1104 return -1; 1105 1106 return 0; 1107} 1108 1109/* Returns 1 if the cv-qualification signature of TYPE1 is a proper 1110 subset of the cv-qualification signature of TYPE2, and the types 1111 are similar. Returns -1 if the other way 'round, and 0 otherwise. */ 1112 1113int 1114comp_cv_qual_signature (tree type1, tree type2) 1115{ 1116 if (comp_ptr_ttypes_real (type2, type1, -1)) 1117 return 1; 1118 else if (comp_ptr_ttypes_real (type1, type2, -1)) 1119 return -1; 1120 else 1121 return 0; 1122} 1123 1124/* If two types share a common base type, return that basetype. 1125 If there is not a unique most-derived base type, this function 1126 returns ERROR_MARK_NODE. */ 1127 1128static tree 1129common_base_type (tree tt1, tree tt2) 1130{ 1131 tree best = NULL_TREE; 1132 int i; 1133 1134 /* If one is a baseclass of another, that's good enough. */ 1135 if (UNIQUELY_DERIVED_FROM_P (tt1, tt2)) 1136 return tt1; 1137 if (UNIQUELY_DERIVED_FROM_P (tt2, tt1)) 1138 return tt2; 1139 1140 /* Otherwise, try to find a unique baseclass of TT1 1141 that is shared by TT2, and follow that down. */ 1142 for (i = CLASSTYPE_N_BASECLASSES (tt1)-1; i >= 0; i--) 1143 { 1144 tree basetype = TYPE_BINFO_BASETYPE (tt1, i); 1145 tree trial = common_base_type (basetype, tt2); 1146 if (trial) 1147 { 1148 if (trial == error_mark_node) 1149 return trial; 1150 if (best == NULL_TREE) 1151 best = trial; 1152 else if (best != trial) 1153 return error_mark_node; 1154 } 1155 } 1156 1157 /* Same for TT2. */ 1158 for (i = CLASSTYPE_N_BASECLASSES (tt2)-1; i >= 0; i--) 1159 { 1160 tree basetype = TYPE_BINFO_BASETYPE (tt2, i); 1161 tree trial = common_base_type (tt1, basetype); 1162 if (trial) 1163 { 1164 if (trial == error_mark_node) 1165 return trial; 1166 if (best == NULL_TREE) 1167 best = trial; 1168 else if (best != trial) 1169 return error_mark_node; 1170 } 1171 } 1172 return best; 1173} 1174 1175/* Subroutines of `comptypes'. */ 1176 1177/* Return true if two parameter type lists PARMS1 and PARMS2 are 1178 equivalent in the sense that functions with those parameter types 1179 can have equivalent types. The two lists must be equivalent, 1180 element by element. */ 1181 1182bool 1183compparms (tree parms1, tree parms2) 1184{ 1185 tree t1, t2; 1186 1187 /* An unspecified parmlist matches any specified parmlist 1188 whose argument types don't need default promotions. */ 1189 1190 for (t1 = parms1, t2 = parms2; 1191 t1 || t2; 1192 t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2)) 1193 { 1194 /* If one parmlist is shorter than the other, 1195 they fail to match. */ 1196 if (!t1 || !t2) 1197 return false; 1198 if (!same_type_p (TREE_VALUE (t1), TREE_VALUE (t2))) 1199 return false; 1200 } 1201 return true; 1202} 1203 1204 1205/* Process a sizeof or alignof expression where the operand is a 1206 type. */ 1207 1208tree 1209cxx_sizeof_or_alignof_type (tree type, enum tree_code op, bool complain) 1210{ 1211 enum tree_code type_code; 1212 tree value; 1213 const char *op_name; 1214 1215 my_friendly_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR, 20020720); 1216 if (type == error_mark_node) 1217 return error_mark_node; 1218 1219 if (dependent_type_p (type)) 1220 { 1221 value = build_min (op, size_type_node, type); 1222 TREE_READONLY (value) = 1; 1223 return value; 1224 } 1225 1226 op_name = operator_name_info[(int) op].name; 1227 1228 type = non_reference (type); 1229 type_code = TREE_CODE (type); 1230 1231 if (type_code == METHOD_TYPE) 1232 { 1233 if (complain && (pedantic || warn_pointer_arith)) 1234 pedwarn ("invalid application of `%s' to a member function", op_name); 1235 value = size_one_node; 1236 } 1237 else 1238 value = c_sizeof_or_alignof_type (complete_type (type), op, complain); 1239 1240 return value; 1241} 1242 1243/* Process a sizeof or alignof expression where the operand is an 1244 expression. */ 1245 1246tree 1247cxx_sizeof_or_alignof_expr (tree e, enum tree_code op) 1248{ 1249 const char *op_name = operator_name_info[(int) op].name; 1250 1251 if (e == error_mark_node) 1252 return error_mark_node; 1253 1254 if (processing_template_decl) 1255 { 1256 e = build_min (op, size_type_node, e); 1257 TREE_SIDE_EFFECTS (e) = 0; 1258 TREE_READONLY (e) = 1; 1259 1260 return e; 1261 } 1262 1263 if (TREE_CODE (e) == COMPONENT_REF 1264 && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL 1265 && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1))) 1266 { 1267 error ("invalid application of `%s' to a bit-field", op_name); 1268 e = char_type_node; 1269 } 1270 else if (is_overloaded_fn (e)) 1271 { 1272 pedwarn ("ISO C++ forbids applying `%s' to an expression of function type", op_name); 1273 e = char_type_node; 1274 } 1275 else if (type_unknown_p (e)) 1276 { 1277 cxx_incomplete_type_error (e, TREE_TYPE (e)); 1278 e = char_type_node; 1279 } 1280 else 1281 e = TREE_TYPE (e); 1282 1283 return cxx_sizeof_or_alignof_type (e, op, true); 1284} 1285 1286 1287/* EXPR is being used in a context that is not a function call. 1288 Enforce: 1289 1290 [expr.ref] 1291 1292 The expression can be used only as the left-hand operand of a 1293 member function call. 1294 1295 [expr.mptr.operator] 1296 1297 If the result of .* or ->* is a function, then that result can be 1298 used only as the operand for the function call operator (). 1299 1300 by issuing an error message if appropriate. Returns true iff EXPR 1301 violates these rules. */ 1302 1303bool 1304invalid_nonstatic_memfn_p (tree expr) 1305{ 1306 if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) 1307 { 1308 error ("invalid use of non-static member function"); 1309 return true; 1310 } 1311 return false; 1312} 1313 1314/* Perform the conversions in [expr] that apply when an lvalue appears 1315 in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and 1316 function-to-pointer conversions. 1317 1318 In addition manifest constants are replaced by their values. */ 1319 1320tree 1321decay_conversion (tree exp) 1322{ 1323 tree type; 1324 enum tree_code code; 1325 1326 type = TREE_TYPE (exp); 1327 code = TREE_CODE (type); 1328 1329 if (code == REFERENCE_TYPE) 1330 { 1331 exp = convert_from_reference (exp); 1332 type = TREE_TYPE (exp); 1333 code = TREE_CODE (type); 1334 } 1335 1336 if (type == error_mark_node) 1337 return error_mark_node; 1338 1339 if (type_unknown_p (exp)) 1340 { 1341 cxx_incomplete_type_error (exp, TREE_TYPE (exp)); 1342 return error_mark_node; 1343 } 1344 1345 /* Constants can be used directly unless they're not loadable. */ 1346 if (TREE_CODE (exp) == CONST_DECL) 1347 exp = DECL_INITIAL (exp); 1348 /* Replace a nonvolatile const static variable with its value. We 1349 don't do this for arrays, though; we want the address of the 1350 first element of the array, not the address of the first element 1351 of its initializing constant. */ 1352 else if (code != ARRAY_TYPE) 1353 { 1354 exp = decl_constant_value (exp); 1355 type = TREE_TYPE (exp); 1356 } 1357 1358 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 1359 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */ 1360 1361 if (code == VOID_TYPE) 1362 { 1363 error ("void value not ignored as it ought to be"); 1364 return error_mark_node; 1365 } 1366 if (invalid_nonstatic_memfn_p (exp)) 1367 return error_mark_node; 1368 if (code == FUNCTION_TYPE || is_overloaded_fn (exp)) 1369 return build_unary_op (ADDR_EXPR, exp, 0); 1370 if (code == ARRAY_TYPE) 1371 { 1372 tree adr; 1373 tree ptrtype; 1374 1375 if (TREE_CODE (exp) == INDIRECT_REF) 1376 return build_nop (build_pointer_type (TREE_TYPE (type)), 1377 TREE_OPERAND (exp, 0)); 1378 1379 if (TREE_CODE (exp) == COMPOUND_EXPR) 1380 { 1381 tree op1 = decay_conversion (TREE_OPERAND (exp, 1)); 1382 return build (COMPOUND_EXPR, TREE_TYPE (op1), 1383 TREE_OPERAND (exp, 0), op1); 1384 } 1385 1386 if (!lvalue_p (exp) 1387 && ! (TREE_CODE (exp) == CONSTRUCTOR && TREE_STATIC (exp))) 1388 { 1389 error ("invalid use of non-lvalue array"); 1390 return error_mark_node; 1391 } 1392 1393 ptrtype = build_pointer_type (TREE_TYPE (type)); 1394 1395 if (TREE_CODE (exp) == VAR_DECL) 1396 { 1397 if (!cxx_mark_addressable (exp)) 1398 return error_mark_node; 1399 adr = build_nop (ptrtype, build_address (exp)); 1400 TREE_SIDE_EFFECTS (adr) = 0; /* Default would be, same as EXP. */ 1401 return adr; 1402 } 1403 /* This way is better for a COMPONENT_REF since it can 1404 simplify the offset for a component. */ 1405 adr = build_unary_op (ADDR_EXPR, exp, 1); 1406 return cp_convert (ptrtype, adr); 1407 } 1408 1409 /* [basic.lval]: Class rvalues can have cv-qualified types; non-class 1410 rvalues always have cv-unqualified types. */ 1411 if (! CLASS_TYPE_P (type)) 1412 exp = cp_convert (TYPE_MAIN_VARIANT (type), exp); 1413 1414 return exp; 1415} 1416 1417tree 1418default_conversion (tree exp) 1419{ 1420 exp = decay_conversion (exp); 1421 1422 if (INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (exp))) 1423 exp = perform_integral_promotions (exp); 1424 1425 return exp; 1426} 1427 1428/* EXPR is an expression with an integral or enumeration type. 1429 Perform the integral promotions in [conv.prom], and return the 1430 converted value. */ 1431 1432tree 1433perform_integral_promotions (tree expr) 1434{ 1435 tree type; 1436 tree promoted_type; 1437 1438 type = TREE_TYPE (expr); 1439 my_friendly_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type), 20030703); 1440 promoted_type = type_promotes_to (type); 1441 if (type != promoted_type) 1442 expr = cp_convert (promoted_type, expr); 1443 return expr; 1444} 1445 1446/* Take the address of an inline function without setting TREE_ADDRESSABLE 1447 or TREE_USED. */ 1448 1449tree 1450inline_conversion (tree exp) 1451{ 1452 if (TREE_CODE (exp) == FUNCTION_DECL) 1453 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp); 1454 1455 return exp; 1456} 1457 1458/* Returns nonzero iff exp is a STRING_CST or the result of applying 1459 decay_conversion to one. */ 1460 1461int 1462string_conv_p (tree totype, tree exp, int warn) 1463{ 1464 tree t; 1465 1466 if (! flag_const_strings || TREE_CODE (totype) != POINTER_TYPE) 1467 return 0; 1468 1469 t = TREE_TYPE (totype); 1470 if (!same_type_p (t, char_type_node) 1471 && !same_type_p (t, wchar_type_node)) 1472 return 0; 1473 1474 if (TREE_CODE (exp) == STRING_CST) 1475 { 1476 /* Make sure that we don't try to convert between char and wchar_t. */ 1477 if (!same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (exp))), t)) 1478 return 0; 1479 } 1480 else 1481 { 1482 /* Is this a string constant which has decayed to 'const char *'? */ 1483 t = build_pointer_type (build_qualified_type (t, TYPE_QUAL_CONST)); 1484 if (!same_type_p (TREE_TYPE (exp), t)) 1485 return 0; 1486 STRIP_NOPS (exp); 1487 if (TREE_CODE (exp) != ADDR_EXPR 1488 || TREE_CODE (TREE_OPERAND (exp, 0)) != STRING_CST) 1489 return 0; 1490 } 1491 1492 /* This warning is not very useful, as it complains about printf. */ 1493 if (warn && warn_write_strings) 1494 warning ("deprecated conversion from string constant to `%T'", totype); 1495 1496 return 1; 1497} 1498 1499/* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we 1500 can, for example, use as an lvalue. This code used to be in 1501 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c' 1502 expressions, where we're dealing with aggregates. But now it's again only 1503 called from unary_complex_lvalue. The case (in particular) that led to 1504 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd 1505 get it there. */ 1506 1507static tree 1508rationalize_conditional_expr (enum tree_code code, tree t) 1509{ 1510 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that 1511 the first operand is always the one to be used if both operands 1512 are equal, so we know what conditional expression this used to be. */ 1513 if (TREE_CODE (t) == MIN_EXPR || TREE_CODE (t) == MAX_EXPR) 1514 { 1515 return 1516 build_conditional_expr (build_x_binary_op ((TREE_CODE (t) == MIN_EXPR 1517 ? LE_EXPR : GE_EXPR), 1518 TREE_OPERAND (t, 0), 1519 TREE_OPERAND (t, 1), 1520 /*overloaded_p=*/NULL), 1521 build_unary_op (code, TREE_OPERAND (t, 0), 0), 1522 build_unary_op (code, TREE_OPERAND (t, 1), 0)); 1523 } 1524 1525 return 1526 build_conditional_expr (TREE_OPERAND (t, 0), 1527 build_unary_op (code, TREE_OPERAND (t, 1), 0), 1528 build_unary_op (code, TREE_OPERAND (t, 2), 0)); 1529} 1530 1531/* Given the TYPE of an anonymous union field inside T, return the 1532 FIELD_DECL for the field. If not found return NULL_TREE. Because 1533 anonymous unions can nest, we must also search all anonymous unions 1534 that are directly reachable. */ 1535 1536tree 1537lookup_anon_field (tree t, tree type) 1538{ 1539 tree field; 1540 1541 for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field)) 1542 { 1543 if (TREE_STATIC (field)) 1544 continue; 1545 if (TREE_CODE (field) != FIELD_DECL || DECL_ARTIFICIAL (field)) 1546 continue; 1547 1548 /* If we find it directly, return the field. */ 1549 if (DECL_NAME (field) == NULL_TREE 1550 && type == TYPE_MAIN_VARIANT (TREE_TYPE (field))) 1551 { 1552 return field; 1553 } 1554 1555 /* Otherwise, it could be nested, search harder. */ 1556 if (DECL_NAME (field) == NULL_TREE 1557 && ANON_AGGR_TYPE_P (TREE_TYPE (field))) 1558 { 1559 tree subfield = lookup_anon_field (TREE_TYPE (field), type); 1560 if (subfield) 1561 return subfield; 1562 } 1563 } 1564 return NULL_TREE; 1565} 1566 1567/* Build an expression representing OBJECT.MEMBER. OBJECT is an 1568 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is 1569 non-NULL, it indicates the path to the base used to name MEMBER. 1570 If PRESERVE_REFERENCE is true, the expression returned will have 1571 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression 1572 returned will have the type referred to by the reference. 1573 1574 This function does not perform access control; that is either done 1575 earlier by the parser when the name of MEMBER is resolved to MEMBER 1576 itself, or later when overload resolution selects one of the 1577 functions indicated by MEMBER. */ 1578 1579tree 1580build_class_member_access_expr (tree object, tree member, 1581 tree access_path, bool preserve_reference) 1582{ 1583 tree object_type; 1584 tree member_scope; 1585 tree result = NULL_TREE; 1586 1587 if (object == error_mark_node || member == error_mark_node) 1588 return error_mark_node; 1589 1590 if (TREE_CODE (member) == PSEUDO_DTOR_EXPR) 1591 return member; 1592 1593 my_friendly_assert (DECL_P (member) || BASELINK_P (member), 1594 20020801); 1595 1596 /* [expr.ref] 1597 1598 The type of the first expression shall be "class object" (of a 1599 complete type). */ 1600 object_type = TREE_TYPE (object); 1601 if (!currently_open_class (object_type) 1602 && !complete_type_or_else (object_type, object)) 1603 return error_mark_node; 1604 if (!CLASS_TYPE_P (object_type)) 1605 { 1606 error ("request for member `%D' in `%E', which is of non-class type `%T'", 1607 member, object, object_type); 1608 return error_mark_node; 1609 } 1610 1611 /* The standard does not seem to actually say that MEMBER must be a 1612 member of OBJECT_TYPE. However, that is clearly what is 1613 intended. */ 1614 if (DECL_P (member)) 1615 { 1616 member_scope = DECL_CLASS_CONTEXT (member); 1617 mark_used (member); 1618 if (TREE_DEPRECATED (member)) 1619 warn_deprecated_use (member); 1620 } 1621 else 1622 member_scope = BINFO_TYPE (BASELINK_BINFO (member)); 1623 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will 1624 presently be the anonymous union. Go outwards until we find a 1625 type related to OBJECT_TYPE. */ 1626 while (ANON_AGGR_TYPE_P (member_scope) 1627 && !same_type_ignoring_top_level_qualifiers_p (member_scope, 1628 object_type)) 1629 member_scope = TYPE_CONTEXT (member_scope); 1630 if (!member_scope || !DERIVED_FROM_P (member_scope, object_type)) 1631 { 1632 if (TREE_CODE (member) == FIELD_DECL) 1633 error ("invalid use of nonstatic data member '%E'", member); 1634 else 1635 error ("`%D' is not a member of `%T'", member, object_type); 1636 return error_mark_node; 1637 } 1638 1639 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into 1640 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue 1641 in the frontend; only _DECLs and _REFs are lvalues in the backend. */ 1642 { 1643 tree temp = unary_complex_lvalue (ADDR_EXPR, object); 1644 if (temp) 1645 object = build_indirect_ref (temp, NULL); 1646 } 1647 1648 /* In [expr.ref], there is an explicit list of the valid choices for 1649 MEMBER. We check for each of those cases here. */ 1650 if (TREE_CODE (member) == VAR_DECL) 1651 { 1652 /* A static data member. */ 1653 result = member; 1654 /* If OBJECT has side-effects, they are supposed to occur. */ 1655 if (TREE_SIDE_EFFECTS (object)) 1656 result = build (COMPOUND_EXPR, TREE_TYPE (result), object, result); 1657 } 1658 else if (TREE_CODE (member) == FIELD_DECL) 1659 { 1660 /* A non-static data member. */ 1661 bool null_object_p; 1662 int type_quals; 1663 tree member_type; 1664 1665 null_object_p = (TREE_CODE (object) == INDIRECT_REF 1666 && integer_zerop (TREE_OPERAND (object, 0))); 1667 1668 /* Convert OBJECT to the type of MEMBER. */ 1669 if (!same_type_p (TYPE_MAIN_VARIANT (object_type), 1670 TYPE_MAIN_VARIANT (member_scope))) 1671 { 1672 tree binfo; 1673 base_kind kind; 1674 1675 binfo = lookup_base (access_path ? access_path : object_type, 1676 member_scope, ba_ignore, &kind); 1677 if (binfo == error_mark_node) 1678 return error_mark_node; 1679 1680 /* It is invalid to try to get to a virtual base of a 1681 NULL object. The most common cause is invalid use of 1682 offsetof macro. */ 1683 if (null_object_p && kind == bk_via_virtual) 1684 { 1685 error ("invalid access to non-static data member `%D' of NULL object", 1686 member); 1687 error ("(perhaps the `offsetof' macro was used incorrectly)"); 1688 return error_mark_node; 1689 } 1690 1691 /* Convert to the base. */ 1692 object = build_base_path (PLUS_EXPR, object, binfo, 1693 /*nonnull=*/1); 1694 /* If we found the base successfully then we should be able 1695 to convert to it successfully. */ 1696 my_friendly_assert (object != error_mark_node, 1697 20020801); 1698 } 1699 1700 /* Complain about other invalid uses of offsetof, even though they will 1701 give the right answer. Note that we complain whether or not they 1702 actually used the offsetof macro, since there's no way to know at this 1703 point. So we just give a warning, instead of a pedwarn. */ 1704 if (null_object_p && warn_invalid_offsetof 1705 && CLASSTYPE_NON_POD_P (object_type)) 1706 { 1707 warning ("invalid access to non-static data member `%D' of NULL object", 1708 member); 1709 warning ("(perhaps the `offsetof' macro was used incorrectly)"); 1710 } 1711 1712 /* If MEMBER is from an anonymous aggregate, we have converted 1713 OBJECT so that it refers to the class containing the 1714 anonymous union. Generate a reference to the anonymous union 1715 itself, and recur to find MEMBER. */ 1716 if (ANON_AGGR_TYPE_P (DECL_CONTEXT (member)) 1717 /* When this code is called from build_field_call, the 1718 object already has the type of the anonymous union. 1719 That is because the COMPONENT_REF was already 1720 constructed, and was then disassembled before calling 1721 build_field_call. After the function-call code is 1722 cleaned up, this waste can be eliminated. */ 1723 && (!same_type_ignoring_top_level_qualifiers_p 1724 (TREE_TYPE (object), DECL_CONTEXT (member)))) 1725 { 1726 tree anonymous_union; 1727 1728 anonymous_union = lookup_anon_field (TREE_TYPE (object), 1729 DECL_CONTEXT (member)); 1730 object = build_class_member_access_expr (object, 1731 anonymous_union, 1732 /*access_path=*/NULL_TREE, 1733 preserve_reference); 1734 } 1735 1736 /* Compute the type of the field, as described in [expr.ref]. */ 1737 type_quals = TYPE_UNQUALIFIED; 1738 member_type = TREE_TYPE (member); 1739 if (TREE_CODE (member_type) != REFERENCE_TYPE) 1740 { 1741 type_quals = (cp_type_quals (member_type) 1742 | cp_type_quals (object_type)); 1743 1744 /* A field is const (volatile) if the enclosing object, or the 1745 field itself, is const (volatile). But, a mutable field is 1746 not const, even within a const object. */ 1747 if (DECL_MUTABLE_P (member)) 1748 type_quals &= ~TYPE_QUAL_CONST; 1749 member_type = cp_build_qualified_type (member_type, type_quals); 1750 } 1751 1752 result = fold (build (COMPONENT_REF, member_type, object, member)); 1753 1754 /* Mark the expression const or volatile, as appropriate. Even 1755 though we've dealt with the type above, we still have to mark the 1756 expression itself. */ 1757 if (type_quals & TYPE_QUAL_CONST) 1758 TREE_READONLY (result) = 1; 1759 else if (type_quals & TYPE_QUAL_VOLATILE) 1760 TREE_THIS_VOLATILE (result) = 1; 1761 } 1762 else if (BASELINK_P (member)) 1763 { 1764 /* The member is a (possibly overloaded) member function. */ 1765 tree functions; 1766 tree type; 1767 1768 /* If the MEMBER is exactly one static member function, then we 1769 know the type of the expression. Otherwise, we must wait 1770 until overload resolution has been performed. */ 1771 functions = BASELINK_FUNCTIONS (member); 1772 if (TREE_CODE (functions) == FUNCTION_DECL 1773 && DECL_STATIC_FUNCTION_P (functions)) 1774 type = TREE_TYPE (functions); 1775 else 1776 type = unknown_type_node; 1777 /* Note that we do not convert OBJECT to the BASELINK_BINFO 1778 base. That will happen when the function is called. */ 1779 result = build (COMPONENT_REF, type, object, member); 1780 } 1781 else if (TREE_CODE (member) == CONST_DECL) 1782 { 1783 /* The member is an enumerator. */ 1784 result = member; 1785 /* If OBJECT has side-effects, they are supposed to occur. */ 1786 if (TREE_SIDE_EFFECTS (object)) 1787 result = build (COMPOUND_EXPR, TREE_TYPE (result), 1788 object, result); 1789 } 1790 else 1791 { 1792 error ("invalid use of `%D'", member); 1793 return error_mark_node; 1794 } 1795 1796 if (!preserve_reference) 1797 /* [expr.ref] 1798 1799 If E2 is declared to have type "reference to T", then ... the 1800 type of E1.E2 is T. */ 1801 result = convert_from_reference (result); 1802 1803 return result; 1804} 1805 1806/* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if 1807 SCOPE is NULL, by OBJECT.~DTOR_NAME. */ 1808 1809static tree 1810lookup_destructor (tree object, tree scope, tree dtor_name) 1811{ 1812 tree object_type = TREE_TYPE (object); 1813 tree dtor_type = TREE_OPERAND (dtor_name, 0); 1814 tree expr; 1815 1816 if (scope && !check_dtor_name (scope, dtor_name)) 1817 { 1818 error ("qualified type `%T' does not match destructor name `~%T'", 1819 scope, dtor_type); 1820 return error_mark_node; 1821 } 1822 if (!DERIVED_FROM_P (dtor_type, TYPE_MAIN_VARIANT (object_type))) 1823 { 1824 error ("the type being destroyed is `%T', but the destructor refers to `%T'", 1825 TYPE_MAIN_VARIANT (object_type), dtor_type); 1826 return error_mark_node; 1827 } 1828 if (!TYPE_HAS_DESTRUCTOR (dtor_type)) 1829 return build (PSEUDO_DTOR_EXPR, void_type_node, object, scope, 1830 dtor_type); 1831 expr = lookup_member (dtor_type, complete_dtor_identifier, 1832 /*protect=*/1, /*want_type=*/false); 1833 expr = (adjust_result_of_qualified_name_lookup 1834 (expr, dtor_type, object_type)); 1835 return expr; 1836} 1837 1838/* This function is called by the parser to process a class member 1839 access expression of the form OBJECT.NAME. NAME is a node used by 1840 the parser to represent a name; it is not yet a DECL. It may, 1841 however, be a BASELINK where the BASELINK_FUNCTIONS is a 1842 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and 1843 there is no reason to do the lookup twice, so the parser keeps the 1844 BASELINK. */ 1845 1846tree 1847finish_class_member_access_expr (tree object, tree name) 1848{ 1849 tree expr; 1850 tree object_type; 1851 tree member; 1852 tree access_path = NULL_TREE; 1853 tree orig_object = object; 1854 tree orig_name = name; 1855 1856 if (object == error_mark_node || name == error_mark_node) 1857 return error_mark_node; 1858 1859 object_type = TREE_TYPE (object); 1860 1861 if (processing_template_decl) 1862 { 1863 if (/* If OBJECT_TYPE is dependent, so is OBJECT.NAME. */ 1864 dependent_type_p (object_type) 1865 /* If NAME is just an IDENTIFIER_NODE, then the expression 1866 is dependent. */ 1867 || TREE_CODE (object) == IDENTIFIER_NODE 1868 /* If NAME is "f<args>", where either 'f' or 'args' is 1869 dependent, then the expression is dependent. */ 1870 || (TREE_CODE (name) == TEMPLATE_ID_EXPR 1871 && dependent_template_id_p (TREE_OPERAND (name, 0), 1872 TREE_OPERAND (name, 1))) 1873 /* If NAME is "T::X" where "T" is dependent, then the 1874 expression is dependent. */ 1875 || (TREE_CODE (name) == SCOPE_REF 1876 && TYPE_P (TREE_OPERAND (name, 0)) 1877 && dependent_type_p (TREE_OPERAND (name, 0)))) 1878 return build_min_nt (COMPONENT_REF, object, name); 1879 object = build_non_dependent_expr (object); 1880 } 1881 1882 if (TREE_CODE (object_type) == REFERENCE_TYPE) 1883 { 1884 object = convert_from_reference (object); 1885 object_type = TREE_TYPE (object); 1886 } 1887 1888 /* [expr.ref] 1889 1890 The type of the first expression shall be "class object" (of a 1891 complete type). */ 1892 if (!currently_open_class (object_type) 1893 && !complete_type_or_else (object_type, object)) 1894 return error_mark_node; 1895 if (!CLASS_TYPE_P (object_type)) 1896 { 1897 error ("request for member `%D' in `%E', which is of non-class type `%T'", 1898 name, object, object_type); 1899 return error_mark_node; 1900 } 1901 1902 if (BASELINK_P (name)) 1903 { 1904 /* A member function that has already been looked up. */ 1905 my_friendly_assert ((TREE_CODE (BASELINK_FUNCTIONS (name)) 1906 == TEMPLATE_ID_EXPR), 1907 20020805); 1908 member = name; 1909 } 1910 else 1911 { 1912 bool is_template_id = false; 1913 tree template_args = NULL_TREE; 1914 tree scope; 1915 1916 if (TREE_CODE (name) == TEMPLATE_ID_EXPR) 1917 { 1918 is_template_id = true; 1919 template_args = TREE_OPERAND (name, 1); 1920 name = TREE_OPERAND (name, 0); 1921 1922 if (TREE_CODE (name) == OVERLOAD) 1923 name = DECL_NAME (get_first_fn (name)); 1924 else if (DECL_P (name)) 1925 name = DECL_NAME (name); 1926 } 1927 1928 if (TREE_CODE (name) == SCOPE_REF) 1929 { 1930 /* A qualified name. The qualifying class or namespace `S' has 1931 already been looked up; it is either a TYPE or a 1932 NAMESPACE_DECL. The member name is either an IDENTIFIER_NODE 1933 or a BIT_NOT_EXPR. */ 1934 scope = TREE_OPERAND (name, 0); 1935 name = TREE_OPERAND (name, 1); 1936 my_friendly_assert ((CLASS_TYPE_P (scope) 1937 || TREE_CODE (scope) == NAMESPACE_DECL), 1938 20020804); 1939 my_friendly_assert ((TREE_CODE (name) == IDENTIFIER_NODE 1940 || TREE_CODE (name) == BIT_NOT_EXPR), 1941 20020804); 1942 1943 /* If SCOPE is a namespace, then the qualified name does not 1944 name a member of OBJECT_TYPE. */ 1945 if (TREE_CODE (scope) == NAMESPACE_DECL) 1946 { 1947 error ("`%D::%D' is not a member of `%T'", 1948 scope, name, object_type); 1949 return error_mark_node; 1950 } 1951 1952 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */ 1953 access_path = lookup_base (object_type, scope, ba_check, NULL); 1954 if (access_path == error_mark_node) 1955 return error_mark_node; 1956 if (!access_path) 1957 { 1958 error ("`%T' is not a base of `%T'", scope, object_type); 1959 return error_mark_node; 1960 } 1961 } 1962 else 1963 { 1964 scope = NULL_TREE; 1965 access_path = object_type; 1966 } 1967 1968 if (TREE_CODE (name) == BIT_NOT_EXPR) 1969 member = lookup_destructor (object, scope, name); 1970 else 1971 { 1972 /* Look up the member. */ 1973 member = lookup_member (access_path, name, /*protect=*/1, 1974 /*want_type=*/false); 1975 if (member == NULL_TREE) 1976 { 1977 error ("'%D' has no member named '%E'", object_type, name); 1978 return error_mark_node; 1979 } 1980 if (member == error_mark_node) 1981 return error_mark_node; 1982 } 1983 1984 if (is_template_id) 1985 { 1986 tree template = member; 1987 1988 if (BASELINK_P (template)) 1989 template = lookup_template_function (template, template_args); 1990 else 1991 { 1992 error ("`%D' is not a member template function", name); 1993 return error_mark_node; 1994 } 1995 } 1996 } 1997 1998 if (TREE_DEPRECATED (member)) 1999 warn_deprecated_use (member); 2000 2001 expr = build_class_member_access_expr (object, member, access_path, 2002 /*preserve_reference=*/false); 2003 if (processing_template_decl && expr != error_mark_node) 2004 return build_min_non_dep (COMPONENT_REF, expr, 2005 orig_object, orig_name); 2006 return expr; 2007} 2008 2009/* Return an expression for the MEMBER_NAME field in the internal 2010 representation of PTRMEM, a pointer-to-member function. (Each 2011 pointer-to-member function type gets its own RECORD_TYPE so it is 2012 more convenient to access the fields by name than by FIELD_DECL.) 2013 This routine converts the NAME to a FIELD_DECL and then creates the 2014 node for the complete expression. */ 2015 2016tree 2017build_ptrmemfunc_access_expr (tree ptrmem, tree member_name) 2018{ 2019 tree ptrmem_type; 2020 tree member; 2021 tree member_type; 2022 2023 /* This code is a stripped down version of 2024 build_class_member_access_expr. It does not work to use that 2025 routine directly because it expects the object to be of class 2026 type. */ 2027 ptrmem_type = TREE_TYPE (ptrmem); 2028 my_friendly_assert (TYPE_PTRMEMFUNC_P (ptrmem_type), 20020804); 2029 member = lookup_member (ptrmem_type, member_name, /*protect=*/0, 2030 /*want_type=*/false); 2031 member_type = cp_build_qualified_type (TREE_TYPE (member), 2032 cp_type_quals (ptrmem_type)); 2033 return fold (build (COMPONENT_REF, member_type, ptrmem, member)); 2034} 2035 2036/* Given an expression PTR for a pointer, return an expression 2037 for the value pointed to. 2038 ERRORSTRING is the name of the operator to appear in error messages. 2039 2040 This function may need to overload OPERATOR_FNNAME. 2041 Must also handle REFERENCE_TYPEs for C++. */ 2042 2043tree 2044build_x_indirect_ref (tree expr, const char *errorstring) 2045{ 2046 tree orig_expr = expr; 2047 tree rval; 2048 2049 if (processing_template_decl) 2050 { 2051 if (type_dependent_expression_p (expr)) 2052 return build_min_nt (INDIRECT_REF, expr); 2053 expr = build_non_dependent_expr (expr); 2054 } 2055 2056 rval = build_new_op (INDIRECT_REF, LOOKUP_NORMAL, expr, NULL_TREE, 2057 NULL_TREE, /*overloaded_p=*/NULL); 2058 if (!rval) 2059 rval = build_indirect_ref (expr, errorstring); 2060 2061 if (processing_template_decl && rval != error_mark_node) 2062 return build_min_non_dep (INDIRECT_REF, rval, orig_expr); 2063 else 2064 return rval; 2065} 2066 2067tree 2068build_indirect_ref (tree ptr, const char *errorstring) 2069{ 2070 tree pointer, type; 2071 2072 if (ptr == error_mark_node) 2073 return error_mark_node; 2074 2075 if (ptr == current_class_ptr) 2076 return current_class_ref; 2077 2078 pointer = (TREE_CODE (TREE_TYPE (ptr)) == REFERENCE_TYPE 2079 ? ptr : decay_conversion (ptr)); 2080 type = TREE_TYPE (pointer); 2081 2082 if (TYPE_PTR_P (type) || TREE_CODE (type) == REFERENCE_TYPE) 2083 { 2084 /* [expr.unary.op] 2085 2086 If the type of the expression is "pointer to T," the type 2087 of the result is "T." 2088 2089 We must use the canonical variant because certain parts of 2090 the back end, like fold, do pointer comparisons between 2091 types. */ 2092 tree t = canonical_type_variant (TREE_TYPE (type)); 2093 2094 if (VOID_TYPE_P (t)) 2095 { 2096 /* A pointer to incomplete type (other than cv void) can be 2097 dereferenced [expr.unary.op]/1 */ 2098 error ("`%T' is not a pointer-to-object type", type); 2099 return error_mark_node; 2100 } 2101 else if (TREE_CODE (pointer) == ADDR_EXPR 2102 && same_type_p (t, TREE_TYPE (TREE_OPERAND (pointer, 0)))) 2103 /* The POINTER was something like `&x'. We simplify `*&x' to 2104 `x'. */ 2105 return TREE_OPERAND (pointer, 0); 2106 else 2107 { 2108 tree ref = build1 (INDIRECT_REF, t, pointer); 2109 2110 /* We *must* set TREE_READONLY when dereferencing a pointer to const, 2111 so that we get the proper error message if the result is used 2112 to assign to. Also, &* is supposed to be a no-op. */ 2113 TREE_READONLY (ref) = CP_TYPE_CONST_P (t); 2114 TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t); 2115 TREE_SIDE_EFFECTS (ref) 2116 = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (pointer)); 2117 return ref; 2118 } 2119 } 2120 /* `pointer' won't be an error_mark_node if we were given a 2121 pointer to member, so it's cool to check for this here. */ 2122 else if (TYPE_PTR_TO_MEMBER_P (type)) 2123 error ("invalid use of `%s' on pointer to member", errorstring); 2124 else if (pointer != error_mark_node) 2125 { 2126 if (errorstring) 2127 error ("invalid type argument of `%s'", errorstring); 2128 else 2129 error ("invalid type argument"); 2130 } 2131 return error_mark_node; 2132} 2133 2134/* This handles expressions of the form "a[i]", which denotes 2135 an array reference. 2136 2137 This is logically equivalent in C to *(a+i), but we may do it differently. 2138 If A is a variable or a member, we generate a primitive ARRAY_REF. 2139 This avoids forcing the array out of registers, and can work on 2140 arrays that are not lvalues (for example, members of structures returned 2141 by functions). 2142 2143 If INDEX is of some user-defined type, it must be converted to 2144 integer type. Otherwise, to make a compatible PLUS_EXPR, it 2145 will inherit the type of the array, which will be some pointer type. */ 2146 2147tree 2148build_array_ref (tree array, tree idx) 2149{ 2150 if (idx == 0) 2151 { 2152 error ("subscript missing in array reference"); 2153 return error_mark_node; 2154 } 2155 2156 if (TREE_TYPE (array) == error_mark_node 2157 || TREE_TYPE (idx) == error_mark_node) 2158 return error_mark_node; 2159 2160 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference 2161 inside it. */ 2162 switch (TREE_CODE (array)) 2163 { 2164 case COMPOUND_EXPR: 2165 { 2166 tree value = build_array_ref (TREE_OPERAND (array, 1), idx); 2167 return build (COMPOUND_EXPR, TREE_TYPE (value), 2168 TREE_OPERAND (array, 0), value); 2169 } 2170 2171 case COND_EXPR: 2172 return build_conditional_expr 2173 (TREE_OPERAND (array, 0), 2174 build_array_ref (TREE_OPERAND (array, 1), idx), 2175 build_array_ref (TREE_OPERAND (array, 2), idx)); 2176 2177 default: 2178 break; 2179 } 2180 2181 if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE 2182 && TREE_CODE (array) != INDIRECT_REF) 2183 { 2184 tree rval, type; 2185 2186 /* Subscripting with type char is likely to lose 2187 on a machine where chars are signed. 2188 So warn on any machine, but optionally. 2189 Don't warn for unsigned char since that type is safe. 2190 Don't warn for signed char because anyone who uses that 2191 must have done so deliberately. */ 2192 if (warn_char_subscripts 2193 && TYPE_MAIN_VARIANT (TREE_TYPE (idx)) == char_type_node) 2194 warning ("array subscript has type `char'"); 2195 2196 if (!INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (idx))) 2197 { 2198 error ("array subscript is not an integer"); 2199 return error_mark_node; 2200 } 2201 2202 /* Apply integral promotions *after* noticing character types. 2203 (It is unclear why we do these promotions -- the standard 2204 does not say that we should. In fact, the natual thing would 2205 seem to be to convert IDX to ptrdiff_t; we're performing 2206 pointer arithmetic.) */ 2207 idx = perform_integral_promotions (idx); 2208 2209 /* An array that is indexed by a non-constant 2210 cannot be stored in a register; we must be able to do 2211 address arithmetic on its address. 2212 Likewise an array of elements of variable size. */ 2213 if (TREE_CODE (idx) != INTEGER_CST 2214 || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array))) 2215 && (TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) 2216 != INTEGER_CST))) 2217 { 2218 if (!cxx_mark_addressable (array)) 2219 return error_mark_node; 2220 } 2221 2222 /* An array that is indexed by a constant value which is not within 2223 the array bounds cannot be stored in a register either; because we 2224 would get a crash in store_bit_field/extract_bit_field when trying 2225 to access a non-existent part of the register. */ 2226 if (TREE_CODE (idx) == INTEGER_CST 2227 && TYPE_VALUES (TREE_TYPE (array)) 2228 && ! int_fits_type_p (idx, TYPE_VALUES (TREE_TYPE (array)))) 2229 { 2230 if (!cxx_mark_addressable (array)) 2231 return error_mark_node; 2232 } 2233 2234 if (pedantic && !lvalue_p (array)) 2235 pedwarn ("ISO C++ forbids subscripting non-lvalue array"); 2236 2237 /* Note in C++ it is valid to subscript a `register' array, since 2238 it is valid to take the address of something with that 2239 storage specification. */ 2240 if (extra_warnings) 2241 { 2242 tree foo = array; 2243 while (TREE_CODE (foo) == COMPONENT_REF) 2244 foo = TREE_OPERAND (foo, 0); 2245 if (TREE_CODE (foo) == VAR_DECL && DECL_REGISTER (foo)) 2246 warning ("subscripting array declared `register'"); 2247 } 2248 2249 type = TREE_TYPE (TREE_TYPE (array)); 2250 rval = build (ARRAY_REF, type, array, idx); 2251 /* Array ref is const/volatile if the array elements are 2252 or if the array is.. */ 2253 TREE_READONLY (rval) 2254 |= (CP_TYPE_CONST_P (type) | TREE_READONLY (array)); 2255 TREE_SIDE_EFFECTS (rval) 2256 |= (CP_TYPE_VOLATILE_P (type) | TREE_SIDE_EFFECTS (array)); 2257 TREE_THIS_VOLATILE (rval) 2258 |= (CP_TYPE_VOLATILE_P (type) | TREE_THIS_VOLATILE (array)); 2259 return require_complete_type (fold (rval)); 2260 } 2261 2262 { 2263 tree ar = default_conversion (array); 2264 tree ind = default_conversion (idx); 2265 2266 /* Put the integer in IND to simplify error checking. */ 2267 if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE) 2268 { 2269 tree temp = ar; 2270 ar = ind; 2271 ind = temp; 2272 } 2273 2274 if (ar == error_mark_node) 2275 return ar; 2276 2277 if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE) 2278 { 2279 error ("subscripted value is neither array nor pointer"); 2280 return error_mark_node; 2281 } 2282 if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE) 2283 { 2284 error ("array subscript is not an integer"); 2285 return error_mark_node; 2286 } 2287 2288 return build_indirect_ref (cp_build_binary_op (PLUS_EXPR, ar, ind), 2289 "array indexing"); 2290 } 2291} 2292 2293/* Resolve a pointer to member function. INSTANCE is the object 2294 instance to use, if the member points to a virtual member. 2295 2296 This used to avoid checking for virtual functions if basetype 2297 has no virtual functions, according to an earlier ANSI draft. 2298 With the final ISO C++ rules, such an optimization is 2299 incorrect: A pointer to a derived member can be static_cast 2300 to pointer-to-base-member, as long as the dynamic object 2301 later has the right member. */ 2302 2303tree 2304get_member_function_from_ptrfunc (tree *instance_ptrptr, tree function) 2305{ 2306 if (TREE_CODE (function) == OFFSET_REF) 2307 function = TREE_OPERAND (function, 1); 2308 2309 if (TYPE_PTRMEMFUNC_P (TREE_TYPE (function))) 2310 { 2311 tree idx, delta, e1, e2, e3, vtbl, basetype; 2312 tree fntype = TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (function)); 2313 2314 tree instance_ptr = *instance_ptrptr; 2315 tree instance_save_expr = 0; 2316 if (instance_ptr == error_mark_node) 2317 { 2318 if (TREE_CODE (function) == PTRMEM_CST) 2319 { 2320 /* Extracting the function address from a pmf is only 2321 allowed with -Wno-pmf-conversions. It only works for 2322 pmf constants. */ 2323 e1 = build_addr_func (PTRMEM_CST_MEMBER (function)); 2324 e1 = convert (fntype, e1); 2325 return e1; 2326 } 2327 else 2328 { 2329 error ("object missing in use of `%E'", function); 2330 return error_mark_node; 2331 } 2332 } 2333 2334 if (TREE_SIDE_EFFECTS (instance_ptr)) 2335 instance_ptr = instance_save_expr = save_expr (instance_ptr); 2336 2337 if (TREE_SIDE_EFFECTS (function)) 2338 function = save_expr (function); 2339 2340 /* Start by extracting all the information from the PMF itself. */ 2341 e3 = PFN_FROM_PTRMEMFUNC (function); 2342 delta = build_ptrmemfunc_access_expr (function, delta_identifier); 2343 idx = build1 (NOP_EXPR, vtable_index_type, e3); 2344 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION) 2345 { 2346 case ptrmemfunc_vbit_in_pfn: 2347 e1 = cp_build_binary_op (BIT_AND_EXPR, idx, integer_one_node); 2348 idx = cp_build_binary_op (MINUS_EXPR, idx, integer_one_node); 2349 break; 2350 2351 case ptrmemfunc_vbit_in_delta: 2352 e1 = cp_build_binary_op (BIT_AND_EXPR, delta, integer_one_node); 2353 delta = cp_build_binary_op (RSHIFT_EXPR, delta, integer_one_node); 2354 break; 2355 2356 default: 2357 abort (); 2358 } 2359 2360 /* Convert down to the right base before using the instance. First 2361 use the type... */ 2362 basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (fntype)); 2363 basetype = lookup_base (TREE_TYPE (TREE_TYPE (instance_ptr)), 2364 basetype, ba_check, NULL); 2365 instance_ptr = build_base_path (PLUS_EXPR, instance_ptr, basetype, 1); 2366 if (instance_ptr == error_mark_node) 2367 return error_mark_node; 2368 /* ...and then the delta in the PMF. */ 2369 instance_ptr = build (PLUS_EXPR, TREE_TYPE (instance_ptr), 2370 instance_ptr, delta); 2371 2372 /* Hand back the adjusted 'this' argument to our caller. */ 2373 *instance_ptrptr = instance_ptr; 2374 2375 /* Next extract the vtable pointer from the object. */ 2376 vtbl = build1 (NOP_EXPR, build_pointer_type (vtbl_ptr_type_node), 2377 instance_ptr); 2378 vtbl = build_indirect_ref (vtbl, NULL); 2379 2380 /* Finally, extract the function pointer from the vtable. */ 2381 e2 = fold (build (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, idx)); 2382 e2 = build_indirect_ref (e2, NULL); 2383 TREE_CONSTANT (e2) = 1; 2384 2385 /* When using function descriptors, the address of the 2386 vtable entry is treated as a function pointer. */ 2387 if (TARGET_VTABLE_USES_DESCRIPTORS) 2388 e2 = build1 (NOP_EXPR, TREE_TYPE (e2), 2389 build_unary_op (ADDR_EXPR, e2, /*noconvert=*/1)); 2390 2391 TREE_TYPE (e2) = TREE_TYPE (e3); 2392 e1 = build_conditional_expr (e1, e2, e3); 2393 2394 /* Make sure this doesn't get evaluated first inside one of the 2395 branches of the COND_EXPR. */ 2396 if (instance_save_expr) 2397 e1 = build (COMPOUND_EXPR, TREE_TYPE (e1), 2398 instance_save_expr, e1); 2399 2400 function = e1; 2401 } 2402 return function; 2403} 2404 2405tree 2406build_function_call (tree function, tree params) 2407{ 2408 tree fntype, fndecl; 2409 tree coerced_params; 2410 tree result; 2411 tree name = NULL_TREE, assembler_name = NULL_TREE; 2412 int is_method; 2413 tree original = function; 2414 2415 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 2416 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */ 2417 if (TREE_CODE (function) == NOP_EXPR 2418 && TREE_TYPE (function) == TREE_TYPE (TREE_OPERAND (function, 0))) 2419 function = TREE_OPERAND (function, 0); 2420 2421 if (TREE_CODE (function) == FUNCTION_DECL) 2422 { 2423 name = DECL_NAME (function); 2424 assembler_name = DECL_ASSEMBLER_NAME (function); 2425 2426 mark_used (function); 2427 fndecl = function; 2428 2429 /* Convert anything with function type to a pointer-to-function. */ 2430 if (pedantic && DECL_MAIN_P (function)) 2431 pedwarn ("ISO C++ forbids calling `::main' from within program"); 2432 2433 /* Differs from default_conversion by not setting TREE_ADDRESSABLE 2434 (because calling an inline function does not mean the function 2435 needs to be separately compiled). */ 2436 2437 if (DECL_INLINE (function)) 2438 function = inline_conversion (function); 2439 else 2440 function = build_addr_func (function); 2441 } 2442 else 2443 { 2444 fndecl = NULL_TREE; 2445 2446 function = build_addr_func (function); 2447 } 2448 2449 if (function == error_mark_node) 2450 return error_mark_node; 2451 2452 fntype = TREE_TYPE (function); 2453 2454 if (TYPE_PTRMEMFUNC_P (fntype)) 2455 { 2456 error ("must use .* or ->* to call pointer-to-member function in `%E (...)'", 2457 original); 2458 return error_mark_node; 2459 } 2460 2461 is_method = (TREE_CODE (fntype) == POINTER_TYPE 2462 && TREE_CODE (TREE_TYPE (fntype)) == METHOD_TYPE); 2463 2464 if (!((TREE_CODE (fntype) == POINTER_TYPE 2465 && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE) 2466 || is_method 2467 || TREE_CODE (function) == TEMPLATE_ID_EXPR)) 2468 { 2469 error ("`%E' cannot be used as a function", original); 2470 return error_mark_node; 2471 } 2472 2473 /* fntype now gets the type of function pointed to. */ 2474 fntype = TREE_TYPE (fntype); 2475 2476 /* Convert the parameters to the types declared in the 2477 function prototype, or apply default promotions. */ 2478 2479 coerced_params = convert_arguments (TYPE_ARG_TYPES (fntype), 2480 params, fndecl, LOOKUP_NORMAL); 2481 if (coerced_params == error_mark_node) 2482 return error_mark_node; 2483 2484 /* Check for errors in format strings. */ 2485 2486 if (warn_format) 2487 check_function_format (NULL, TYPE_ATTRIBUTES (fntype), coerced_params); 2488 2489 /* Recognize certain built-in functions so we can make tree-codes 2490 other than CALL_EXPR. We do this when it enables fold-const.c 2491 to do something useful. */ 2492 2493 if (TREE_CODE (function) == ADDR_EXPR 2494 && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL 2495 && DECL_BUILT_IN (TREE_OPERAND (function, 0))) 2496 { 2497 result = expand_tree_builtin (TREE_OPERAND (function, 0), 2498 params, coerced_params); 2499 if (result) 2500 return result; 2501 } 2502 2503 return build_cxx_call (function, params, coerced_params); 2504} 2505 2506/* Convert the actual parameter expressions in the list VALUES 2507 to the types in the list TYPELIST. 2508 If parmdecls is exhausted, or when an element has NULL as its type, 2509 perform the default conversions. 2510 2511 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages. 2512 2513 This is also where warnings about wrong number of args are generated. 2514 2515 Return a list of expressions for the parameters as converted. 2516 2517 Both VALUES and the returned value are chains of TREE_LIST nodes 2518 with the elements of the list in the TREE_VALUE slots of those nodes. 2519 2520 In C++, unspecified trailing parameters can be filled in with their 2521 default arguments, if such were specified. Do so here. */ 2522 2523tree 2524convert_arguments (tree typelist, tree values, tree fndecl, int flags) 2525{ 2526 tree typetail, valtail; 2527 tree result = NULL_TREE; 2528 const char *called_thing = 0; 2529 int i = 0; 2530 2531 /* Argument passing is always copy-initialization. */ 2532 flags |= LOOKUP_ONLYCONVERTING; 2533 2534 if (fndecl) 2535 { 2536 if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE) 2537 { 2538 if (DECL_NAME (fndecl) == NULL_TREE 2539 || IDENTIFIER_HAS_TYPE_VALUE (DECL_NAME (fndecl))) 2540 called_thing = "constructor"; 2541 else 2542 called_thing = "member function"; 2543 } 2544 else 2545 called_thing = "function"; 2546 } 2547 2548 for (valtail = values, typetail = typelist; 2549 valtail; 2550 valtail = TREE_CHAIN (valtail), i++) 2551 { 2552 tree type = typetail ? TREE_VALUE (typetail) : 0; 2553 tree val = TREE_VALUE (valtail); 2554 2555 if (val == error_mark_node) 2556 return error_mark_node; 2557 2558 if (type == void_type_node) 2559 { 2560 if (fndecl) 2561 { 2562 cp_error_at ("too many arguments to %s `%+#D'", called_thing, 2563 fndecl); 2564 error ("at this point in file"); 2565 } 2566 else 2567 error ("too many arguments to function"); 2568 /* In case anybody wants to know if this argument 2569 list is valid. */ 2570 if (result) 2571 TREE_TYPE (tree_last (result)) = error_mark_node; 2572 break; 2573 } 2574 2575 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 2576 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */ 2577 if (TREE_CODE (val) == NOP_EXPR 2578 && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0)) 2579 && (type == 0 || TREE_CODE (type) != REFERENCE_TYPE)) 2580 val = TREE_OPERAND (val, 0); 2581 2582 if (type == 0 || TREE_CODE (type) != REFERENCE_TYPE) 2583 { 2584 if (TREE_CODE (TREE_TYPE (val)) == ARRAY_TYPE 2585 || TREE_CODE (TREE_TYPE (val)) == FUNCTION_TYPE 2586 || TREE_CODE (TREE_TYPE (val)) == METHOD_TYPE) 2587 val = decay_conversion (val); 2588 } 2589 2590 if (val == error_mark_node) 2591 return error_mark_node; 2592 2593 if (type != 0) 2594 { 2595 /* Formal parm type is specified by a function prototype. */ 2596 tree parmval; 2597 2598 if (!COMPLETE_TYPE_P (complete_type (type))) 2599 { 2600 if (fndecl) 2601 error ("parameter %P of `%D' has incomplete type `%T'", 2602 i, fndecl, type); 2603 else 2604 error ("parameter %P has incomplete type `%T'", i, type); 2605 parmval = error_mark_node; 2606 } 2607 else 2608 { 2609 parmval = convert_for_initialization 2610 (NULL_TREE, type, val, flags, 2611 "argument passing", fndecl, i); 2612 parmval = convert_for_arg_passing (type, parmval); 2613 } 2614 2615 if (parmval == error_mark_node) 2616 return error_mark_node; 2617 2618 result = tree_cons (NULL_TREE, parmval, result); 2619 } 2620 else 2621 { 2622 if (TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE) 2623 val = convert_from_reference (val); 2624 2625 if (fndecl && DECL_BUILT_IN (fndecl) 2626 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P) 2627 /* Don't do ellipsis conversion for __built_in_constant_p 2628 as this will result in spurious warnings for non-POD 2629 types. */ 2630 val = require_complete_type (val); 2631 else 2632 val = convert_arg_to_ellipsis (val); 2633 2634 result = tree_cons (NULL_TREE, val, result); 2635 } 2636 2637 if (typetail) 2638 typetail = TREE_CHAIN (typetail); 2639 } 2640 2641 if (typetail != 0 && typetail != void_list_node) 2642 { 2643 /* See if there are default arguments that can be used. */ 2644 if (TREE_PURPOSE (typetail) 2645 && TREE_CODE (TREE_PURPOSE (typetail)) != DEFAULT_ARG) 2646 { 2647 for (; typetail != void_list_node; ++i) 2648 { 2649 tree parmval 2650 = convert_default_arg (TREE_VALUE (typetail), 2651 TREE_PURPOSE (typetail), 2652 fndecl, i); 2653 2654 if (parmval == error_mark_node) 2655 return error_mark_node; 2656 2657 result = tree_cons (0, parmval, result); 2658 typetail = TREE_CHAIN (typetail); 2659 /* ends with `...'. */ 2660 if (typetail == NULL_TREE) 2661 break; 2662 } 2663 } 2664 else 2665 { 2666 if (fndecl) 2667 { 2668 cp_error_at ("too few arguments to %s `%+#D'", 2669 called_thing, fndecl); 2670 error ("at this point in file"); 2671 } 2672 else 2673 error ("too few arguments to function"); 2674 return error_mark_list; 2675 } 2676 } 2677 2678 return nreverse (result); 2679} 2680 2681/* Build a binary-operation expression, after performing default 2682 conversions on the operands. CODE is the kind of expression to build. */ 2683 2684tree 2685build_x_binary_op (enum tree_code code, tree arg1, tree arg2, 2686 bool *overloaded_p) 2687{ 2688 tree orig_arg1; 2689 tree orig_arg2; 2690 tree expr; 2691 2692 orig_arg1 = arg1; 2693 orig_arg2 = arg2; 2694 2695 if (processing_template_decl) 2696 { 2697 if (type_dependent_expression_p (arg1) 2698 || type_dependent_expression_p (arg2)) 2699 return build_min_nt (code, arg1, arg2); 2700 arg1 = build_non_dependent_expr (arg1); 2701 arg2 = build_non_dependent_expr (arg2); 2702 } 2703 2704 if (code == DOTSTAR_EXPR) 2705 expr = build_m_component_ref (arg1, arg2); 2706 else 2707 expr = build_new_op (code, LOOKUP_NORMAL, arg1, arg2, NULL_TREE, 2708 overloaded_p); 2709 2710 if (processing_template_decl && expr != error_mark_node) 2711 return build_min_non_dep (code, expr, orig_arg1, orig_arg2); 2712 2713 return expr; 2714} 2715 2716/* Build a binary-operation expression without default conversions. 2717 CODE is the kind of expression to build. 2718 This function differs from `build' in several ways: 2719 the data type of the result is computed and recorded in it, 2720 warnings are generated if arg data types are invalid, 2721 special handling for addition and subtraction of pointers is known, 2722 and some optimization is done (operations on narrow ints 2723 are done in the narrower type when that gives the same result). 2724 Constant folding is also done before the result is returned. 2725 2726 Note that the operands will never have enumeral types 2727 because either they have just had the default conversions performed 2728 or they have both just been converted to some other type in which 2729 the arithmetic is to be done. 2730 2731 C++: must do special pointer arithmetic when implementing 2732 multiple inheritance, and deal with pointer to member functions. */ 2733 2734tree 2735build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1, 2736 int convert_p ATTRIBUTE_UNUSED) 2737{ 2738 tree op0, op1; 2739 enum tree_code code0, code1; 2740 tree type0, type1; 2741 2742 /* Expression code to give to the expression when it is built. 2743 Normally this is CODE, which is what the caller asked for, 2744 but in some special cases we change it. */ 2745 enum tree_code resultcode = code; 2746 2747 /* Data type in which the computation is to be performed. 2748 In the simplest cases this is the common type of the arguments. */ 2749 tree result_type = NULL; 2750 2751 /* Nonzero means operands have already been type-converted 2752 in whatever way is necessary. 2753 Zero means they need to be converted to RESULT_TYPE. */ 2754 int converted = 0; 2755 2756 /* Nonzero means create the expression with this type, rather than 2757 RESULT_TYPE. */ 2758 tree build_type = 0; 2759 2760 /* Nonzero means after finally constructing the expression 2761 convert it to this type. */ 2762 tree final_type = 0; 2763 2764 /* Nonzero if this is an operation like MIN or MAX which can 2765 safely be computed in short if both args are promoted shorts. 2766 Also implies COMMON. 2767 -1 indicates a bitwise operation; this makes a difference 2768 in the exact conditions for when it is safe to do the operation 2769 in a narrower mode. */ 2770 int shorten = 0; 2771 2772 /* Nonzero if this is a comparison operation; 2773 if both args are promoted shorts, compare the original shorts. 2774 Also implies COMMON. */ 2775 int short_compare = 0; 2776 2777 /* Nonzero if this is a right-shift operation, which can be computed on the 2778 original short and then promoted if the operand is a promoted short. */ 2779 int short_shift = 0; 2780 2781 /* Nonzero means set RESULT_TYPE to the common type of the args. */ 2782 int common = 0; 2783 2784 /* Apply default conversions. */ 2785 op0 = orig_op0; 2786 op1 = orig_op1; 2787 2788 if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR 2789 || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR 2790 || code == TRUTH_XOR_EXPR) 2791 { 2792 if (!really_overloaded_fn (op0)) 2793 op0 = decay_conversion (op0); 2794 if (!really_overloaded_fn (op1)) 2795 op1 = decay_conversion (op1); 2796 } 2797 else 2798 { 2799 if (!really_overloaded_fn (op0)) 2800 op0 = default_conversion (op0); 2801 if (!really_overloaded_fn (op1)) 2802 op1 = default_conversion (op1); 2803 } 2804 2805 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */ 2806 STRIP_TYPE_NOPS (op0); 2807 STRIP_TYPE_NOPS (op1); 2808 2809 /* DTRT if one side is an overloaded function, but complain about it. */ 2810 if (type_unknown_p (op0)) 2811 { 2812 tree t = instantiate_type (TREE_TYPE (op1), op0, tf_none); 2813 if (t != error_mark_node) 2814 { 2815 pedwarn ("assuming cast to type `%T' from overloaded function", 2816 TREE_TYPE (t)); 2817 op0 = t; 2818 } 2819 } 2820 if (type_unknown_p (op1)) 2821 { 2822 tree t = instantiate_type (TREE_TYPE (op0), op1, tf_none); 2823 if (t != error_mark_node) 2824 { 2825 pedwarn ("assuming cast to type `%T' from overloaded function", 2826 TREE_TYPE (t)); 2827 op1 = t; 2828 } 2829 } 2830 2831 type0 = TREE_TYPE (op0); 2832 type1 = TREE_TYPE (op1); 2833 2834 /* The expression codes of the data types of the arguments tell us 2835 whether the arguments are integers, floating, pointers, etc. */ 2836 code0 = TREE_CODE (type0); 2837 code1 = TREE_CODE (type1); 2838 2839 /* If an error was already reported for one of the arguments, 2840 avoid reporting another error. */ 2841 2842 if (code0 == ERROR_MARK || code1 == ERROR_MARK) 2843 return error_mark_node; 2844 2845 switch (code) 2846 { 2847 case PLUS_EXPR: 2848 /* Handle the pointer + int case. */ 2849 if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE) 2850 return cp_pointer_int_sum (PLUS_EXPR, op0, op1); 2851 else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE) 2852 return cp_pointer_int_sum (PLUS_EXPR, op1, op0); 2853 else 2854 common = 1; 2855 break; 2856 2857 case MINUS_EXPR: 2858 /* Subtraction of two similar pointers. 2859 We must subtract them as integers, then divide by object size. */ 2860 if (code0 == POINTER_TYPE && code1 == POINTER_TYPE 2861 && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (type0), 2862 TREE_TYPE (type1))) 2863 return pointer_diff (op0, op1, common_type (type0, type1)); 2864 /* Handle pointer minus int. Just like pointer plus int. */ 2865 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE) 2866 return cp_pointer_int_sum (MINUS_EXPR, op0, op1); 2867 else 2868 common = 1; 2869 break; 2870 2871 case MULT_EXPR: 2872 common = 1; 2873 break; 2874 2875 case TRUNC_DIV_EXPR: 2876 case CEIL_DIV_EXPR: 2877 case FLOOR_DIV_EXPR: 2878 case ROUND_DIV_EXPR: 2879 case EXACT_DIV_EXPR: 2880 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE 2881 || code0 == COMPLEX_TYPE) 2882 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 2883 || code1 == COMPLEX_TYPE)) 2884 { 2885 if (TREE_CODE (op1) == INTEGER_CST && integer_zerop (op1)) 2886 warning ("division by zero in `%E / 0'", op0); 2887 else if (TREE_CODE (op1) == REAL_CST && real_zerop (op1)) 2888 warning ("division by zero in `%E / 0.'", op0); 2889 2890 if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)) 2891 resultcode = RDIV_EXPR; 2892 else 2893 /* When dividing two signed integers, we have to promote to int. 2894 unless we divide by a constant != -1. Note that default 2895 conversion will have been performed on the operands at this 2896 point, so we have to dig out the original type to find out if 2897 it was unsigned. */ 2898 shorten = ((TREE_CODE (op0) == NOP_EXPR 2899 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0)))) 2900 || (TREE_CODE (op1) == INTEGER_CST 2901 && ! integer_all_onesp (op1))); 2902 2903 common = 1; 2904 } 2905 break; 2906 2907 case BIT_AND_EXPR: 2908 case BIT_IOR_EXPR: 2909 case BIT_XOR_EXPR: 2910 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 2911 shorten = -1; 2912 break; 2913 2914 case TRUNC_MOD_EXPR: 2915 case FLOOR_MOD_EXPR: 2916 if (code1 == INTEGER_TYPE && integer_zerop (op1)) 2917 warning ("division by zero in `%E %% 0'", op0); 2918 else if (code1 == REAL_TYPE && real_zerop (op1)) 2919 warning ("division by zero in `%E %% 0.'", op0); 2920 2921 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 2922 { 2923 /* Although it would be tempting to shorten always here, that loses 2924 on some targets, since the modulo instruction is undefined if the 2925 quotient can't be represented in the computation mode. We shorten 2926 only if unsigned or if dividing by something we know != -1. */ 2927 shorten = ((TREE_CODE (op0) == NOP_EXPR 2928 && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0)))) 2929 || (TREE_CODE (op1) == INTEGER_CST 2930 && ! integer_all_onesp (op1))); 2931 common = 1; 2932 } 2933 break; 2934 2935 case TRUTH_ANDIF_EXPR: 2936 case TRUTH_ORIF_EXPR: 2937 case TRUTH_AND_EXPR: 2938 case TRUTH_OR_EXPR: 2939 result_type = boolean_type_node; 2940 break; 2941 2942 /* Shift operations: result has same type as first operand; 2943 always convert second operand to int. 2944 Also set SHORT_SHIFT if shifting rightward. */ 2945 2946 case RSHIFT_EXPR: 2947 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 2948 { 2949 result_type = type0; 2950 if (TREE_CODE (op1) == INTEGER_CST) 2951 { 2952 if (tree_int_cst_lt (op1, integer_zero_node)) 2953 warning ("right shift count is negative"); 2954 else 2955 { 2956 if (! integer_zerop (op1)) 2957 short_shift = 1; 2958 if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 2959 warning ("right shift count >= width of type"); 2960 } 2961 } 2962 /* Convert the shift-count to an integer, regardless of 2963 size of value being shifted. */ 2964 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 2965 op1 = cp_convert (integer_type_node, op1); 2966 /* Avoid converting op1 to result_type later. */ 2967 converted = 1; 2968 } 2969 break; 2970 2971 case LSHIFT_EXPR: 2972 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 2973 { 2974 result_type = type0; 2975 if (TREE_CODE (op1) == INTEGER_CST) 2976 { 2977 if (tree_int_cst_lt (op1, integer_zero_node)) 2978 warning ("left shift count is negative"); 2979 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 2980 warning ("left shift count >= width of type"); 2981 } 2982 /* Convert the shift-count to an integer, regardless of 2983 size of value being shifted. */ 2984 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 2985 op1 = cp_convert (integer_type_node, op1); 2986 /* Avoid converting op1 to result_type later. */ 2987 converted = 1; 2988 } 2989 break; 2990 2991 case RROTATE_EXPR: 2992 case LROTATE_EXPR: 2993 if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) 2994 { 2995 result_type = type0; 2996 if (TREE_CODE (op1) == INTEGER_CST) 2997 { 2998 if (tree_int_cst_lt (op1, integer_zero_node)) 2999 warning ("%s rotate count is negative", 3000 (code == LROTATE_EXPR) ? "left" : "right"); 3001 else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0) 3002 warning ("%s rotate count >= width of type", 3003 (code == LROTATE_EXPR) ? "left" : "right"); 3004 } 3005 /* Convert the shift-count to an integer, regardless of 3006 size of value being shifted. */ 3007 if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node) 3008 op1 = cp_convert (integer_type_node, op1); 3009 } 3010 break; 3011 3012 case EQ_EXPR: 3013 case NE_EXPR: 3014 if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE)) 3015 warning ("comparing floating point with == or != is unsafe"); 3016 3017 build_type = boolean_type_node; 3018 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE 3019 || code0 == COMPLEX_TYPE) 3020 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE 3021 || code1 == COMPLEX_TYPE)) 3022 short_compare = 1; 3023 else if ((code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3024 || (TYPE_PTRMEM_P (type0) && TYPE_PTRMEM_P (type1))) 3025 result_type = composite_pointer_type (type0, type1, op0, op1, 3026 "comparison"); 3027 else if ((code0 == POINTER_TYPE || TYPE_PTRMEM_P (type0)) 3028 && null_ptr_cst_p (op1)) 3029 result_type = type0; 3030 else if ((code1 == POINTER_TYPE || TYPE_PTRMEM_P (type1)) 3031 && null_ptr_cst_p (op0)) 3032 result_type = type1; 3033 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE) 3034 { 3035 result_type = type0; 3036 error ("ISO C++ forbids comparison between pointer and integer"); 3037 } 3038 else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE) 3039 { 3040 result_type = type1; 3041 error ("ISO C++ forbids comparison between pointer and integer"); 3042 } 3043 else if (TYPE_PTRMEMFUNC_P (type0) && null_ptr_cst_p (op1)) 3044 { 3045 op0 = build_ptrmemfunc_access_expr (op0, pfn_identifier); 3046 op1 = cp_convert (TREE_TYPE (op0), integer_zero_node); 3047 result_type = TREE_TYPE (op0); 3048 } 3049 else if (TYPE_PTRMEMFUNC_P (type1) && null_ptr_cst_p (op0)) 3050 return cp_build_binary_op (code, op1, op0); 3051 else if (TYPE_PTRMEMFUNC_P (type0) && TYPE_PTRMEMFUNC_P (type1) 3052 && same_type_p (type0, type1)) 3053 { 3054 /* E will be the final comparison. */ 3055 tree e; 3056 /* E1 and E2 are for scratch. */ 3057 tree e1; 3058 tree e2; 3059 tree pfn0; 3060 tree pfn1; 3061 tree delta0; 3062 tree delta1; 3063 3064 if (TREE_SIDE_EFFECTS (op0)) 3065 op0 = save_expr (op0); 3066 if (TREE_SIDE_EFFECTS (op1)) 3067 op1 = save_expr (op1); 3068 3069 /* We generate: 3070 3071 (op0.pfn == op1.pfn 3072 && (!op0.pfn || op0.delta == op1.delta)) 3073 3074 The reason for the `!op0.pfn' bit is that a NULL 3075 pointer-to-member is any member with a zero PFN; the 3076 DELTA field is unspecified. */ 3077 pfn0 = pfn_from_ptrmemfunc (op0); 3078 pfn1 = pfn_from_ptrmemfunc (op1); 3079 delta0 = build_ptrmemfunc_access_expr (op0, 3080 delta_identifier); 3081 delta1 = build_ptrmemfunc_access_expr (op1, 3082 delta_identifier); 3083 e1 = cp_build_binary_op (EQ_EXPR, delta0, delta1); 3084 e2 = cp_build_binary_op (EQ_EXPR, 3085 pfn0, 3086 cp_convert (TREE_TYPE (pfn0), 3087 integer_zero_node)); 3088 e1 = cp_build_binary_op (TRUTH_ORIF_EXPR, e1, e2); 3089 e2 = build (EQ_EXPR, boolean_type_node, pfn0, pfn1); 3090 e = cp_build_binary_op (TRUTH_ANDIF_EXPR, e2, e1); 3091 if (code == EQ_EXPR) 3092 return e; 3093 return cp_build_binary_op (EQ_EXPR, e, integer_zero_node); 3094 } 3095 else if ((TYPE_PTRMEMFUNC_P (type0) 3096 && same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type0), type1)) 3097 || (TYPE_PTRMEMFUNC_P (type1) 3098 && same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type1), type0))) 3099 abort (); 3100 break; 3101 3102 case MAX_EXPR: 3103 case MIN_EXPR: 3104 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE) 3105 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE)) 3106 shorten = 1; 3107 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3108 result_type = composite_pointer_type (type0, type1, op0, op1, 3109 "comparison"); 3110 break; 3111 3112 case LE_EXPR: 3113 case GE_EXPR: 3114 case LT_EXPR: 3115 case GT_EXPR: 3116 build_type = boolean_type_node; 3117 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE) 3118 && (code1 == INTEGER_TYPE || code1 == REAL_TYPE)) 3119 short_compare = 1; 3120 else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE) 3121 result_type = composite_pointer_type (type0, type1, op0, op1, 3122 "comparison"); 3123 else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST 3124 && integer_zerop (op1)) 3125 result_type = type0; 3126 else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST 3127 && integer_zerop (op0)) 3128 result_type = type1; 3129 else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE) 3130 { 3131 result_type = type0; 3132 pedwarn ("ISO C++ forbids comparison between pointer and integer"); 3133 } 3134 else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE) 3135 { 3136 result_type = type1; 3137 pedwarn ("ISO C++ forbids comparison between pointer and integer"); 3138 } 3139 break; 3140 3141 case UNORDERED_EXPR: 3142 case ORDERED_EXPR: 3143 case UNLT_EXPR: 3144 case UNLE_EXPR: 3145 case UNGT_EXPR: 3146 case UNGE_EXPR: 3147 case UNEQ_EXPR: 3148 build_type = integer_type_node; 3149 if (code0 != REAL_TYPE || code1 != REAL_TYPE) 3150 { 3151 error ("unordered comparison on non-floating point argument"); 3152 return error_mark_node; 3153 } 3154 common = 1; 3155 break; 3156 3157 default: 3158 break; 3159 } 3160 3161 if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE) 3162 && 3163 (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE)) 3164 { 3165 int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE); 3166 3167 if (shorten || common || short_compare) 3168 result_type = common_type (type0, type1); 3169 3170 /* For certain operations (which identify themselves by shorten != 0) 3171 if both args were extended from the same smaller type, 3172 do the arithmetic in that type and then extend. 3173 3174 shorten !=0 and !=1 indicates a bitwise operation. 3175 For them, this optimization is safe only if 3176 both args are zero-extended or both are sign-extended. 3177 Otherwise, we might change the result. 3178 Eg, (short)-1 | (unsigned short)-1 is (int)-1 3179 but calculated in (unsigned short) it would be (unsigned short)-1. */ 3180 3181 if (shorten && none_complex) 3182 { 3183 int unsigned0, unsigned1; 3184 tree arg0 = get_narrower (op0, &unsigned0); 3185 tree arg1 = get_narrower (op1, &unsigned1); 3186 /* UNS is 1 if the operation to be done is an unsigned one. */ 3187 int uns = TREE_UNSIGNED (result_type); 3188 tree type; 3189 3190 final_type = result_type; 3191 3192 /* Handle the case that OP0 does not *contain* a conversion 3193 but it *requires* conversion to FINAL_TYPE. */ 3194 3195 if (op0 == arg0 && TREE_TYPE (op0) != final_type) 3196 unsigned0 = TREE_UNSIGNED (TREE_TYPE (op0)); 3197 if (op1 == arg1 && TREE_TYPE (op1) != final_type) 3198 unsigned1 = TREE_UNSIGNED (TREE_TYPE (op1)); 3199 3200 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */ 3201 3202 /* For bitwise operations, signedness of nominal type 3203 does not matter. Consider only how operands were extended. */ 3204 if (shorten == -1) 3205 uns = unsigned0; 3206 3207 /* Note that in all three cases below we refrain from optimizing 3208 an unsigned operation on sign-extended args. 3209 That would not be valid. */ 3210 3211 /* Both args variable: if both extended in same way 3212 from same width, do it in that width. 3213 Do it unsigned if args were zero-extended. */ 3214 if ((TYPE_PRECISION (TREE_TYPE (arg0)) 3215 < TYPE_PRECISION (result_type)) 3216 && (TYPE_PRECISION (TREE_TYPE (arg1)) 3217 == TYPE_PRECISION (TREE_TYPE (arg0))) 3218 && unsigned0 == unsigned1 3219 && (unsigned0 || !uns)) 3220 result_type = c_common_signed_or_unsigned_type 3221 (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1))); 3222 else if (TREE_CODE (arg0) == INTEGER_CST 3223 && (unsigned1 || !uns) 3224 && (TYPE_PRECISION (TREE_TYPE (arg1)) 3225 < TYPE_PRECISION (result_type)) 3226 && (type = c_common_signed_or_unsigned_type 3227 (unsigned1, TREE_TYPE (arg1)), 3228 int_fits_type_p (arg0, type))) 3229 result_type = type; 3230 else if (TREE_CODE (arg1) == INTEGER_CST 3231 && (unsigned0 || !uns) 3232 && (TYPE_PRECISION (TREE_TYPE (arg0)) 3233 < TYPE_PRECISION (result_type)) 3234 && (type = c_common_signed_or_unsigned_type 3235 (unsigned0, TREE_TYPE (arg0)), 3236 int_fits_type_p (arg1, type))) 3237 result_type = type; 3238 } 3239 3240 /* Shifts can be shortened if shifting right. */ 3241 3242 if (short_shift) 3243 { 3244 int unsigned_arg; 3245 tree arg0 = get_narrower (op0, &unsigned_arg); 3246 3247 final_type = result_type; 3248 3249 if (arg0 == op0 && final_type == TREE_TYPE (op0)) 3250 unsigned_arg = TREE_UNSIGNED (TREE_TYPE (op0)); 3251 3252 if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type) 3253 /* We can shorten only if the shift count is less than the 3254 number of bits in the smaller type size. */ 3255 && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0 3256 /* If arg is sign-extended and then unsigned-shifted, 3257 we can simulate this with a signed shift in arg's type 3258 only if the extended result is at least twice as wide 3259 as the arg. Otherwise, the shift could use up all the 3260 ones made by sign-extension and bring in zeros. 3261 We can't optimize that case at all, but in most machines 3262 it never happens because available widths are 2**N. */ 3263 && (!TREE_UNSIGNED (final_type) 3264 || unsigned_arg 3265 || (((unsigned) 2 * TYPE_PRECISION (TREE_TYPE (arg0))) 3266 <= TYPE_PRECISION (result_type)))) 3267 { 3268 /* Do an unsigned shift if the operand was zero-extended. */ 3269 result_type 3270 = c_common_signed_or_unsigned_type (unsigned_arg, 3271 TREE_TYPE (arg0)); 3272 /* Convert value-to-be-shifted to that type. */ 3273 if (TREE_TYPE (op0) != result_type) 3274 op0 = cp_convert (result_type, op0); 3275 converted = 1; 3276 } 3277 } 3278 3279 /* Comparison operations are shortened too but differently. 3280 They identify themselves by setting short_compare = 1. */ 3281 3282 if (short_compare) 3283 { 3284 /* Don't write &op0, etc., because that would prevent op0 3285 from being kept in a register. 3286 Instead, make copies of the our local variables and 3287 pass the copies by reference, then copy them back afterward. */ 3288 tree xop0 = op0, xop1 = op1, xresult_type = result_type; 3289 enum tree_code xresultcode = resultcode; 3290 tree val 3291 = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode); 3292 if (val != 0) 3293 return cp_convert (boolean_type_node, val); 3294 op0 = xop0, op1 = xop1; 3295 converted = 1; 3296 resultcode = xresultcode; 3297 } 3298 3299 if ((short_compare || code == MIN_EXPR || code == MAX_EXPR) 3300 && warn_sign_compare 3301 /* Do not warn until the template is instantiated; we cannot 3302 bound the ranges of the arguments until that point. */ 3303 && !processing_template_decl) 3304 { 3305 int op0_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op0)); 3306 int op1_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op1)); 3307 3308 int unsignedp0, unsignedp1; 3309 tree primop0 = get_narrower (op0, &unsignedp0); 3310 tree primop1 = get_narrower (op1, &unsignedp1); 3311 3312 /* Check for comparison of different enum types. */ 3313 if (TREE_CODE (TREE_TYPE (orig_op0)) == ENUMERAL_TYPE 3314 && TREE_CODE (TREE_TYPE (orig_op1)) == ENUMERAL_TYPE 3315 && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0)) 3316 != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1))) 3317 { 3318 warning ("comparison between types `%#T' and `%#T'", 3319 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1)); 3320 } 3321 3322 /* Give warnings for comparisons between signed and unsigned 3323 quantities that may fail. */ 3324 /* Do the checking based on the original operand trees, so that 3325 casts will be considered, but default promotions won't be. */ 3326 3327 /* Do not warn if the comparison is being done in a signed type, 3328 since the signed type will only be chosen if it can represent 3329 all the values of the unsigned type. */ 3330 if (! TREE_UNSIGNED (result_type)) 3331 /* OK */; 3332 /* Do not warn if both operands are unsigned. */ 3333 else if (op0_signed == op1_signed) 3334 /* OK */; 3335 /* Do not warn if the signed quantity is an unsuffixed 3336 integer literal (or some static constant expression 3337 involving such literals or a conditional expression 3338 involving such literals) and it is non-negative. */ 3339 else if ((op0_signed && tree_expr_nonnegative_p (orig_op0)) 3340 || (op1_signed && tree_expr_nonnegative_p (orig_op1))) 3341 /* OK */; 3342 /* Do not warn if the comparison is an equality operation, 3343 the unsigned quantity is an integral constant and it does 3344 not use the most significant bit of result_type. */ 3345 else if ((resultcode == EQ_EXPR || resultcode == NE_EXPR) 3346 && ((op0_signed && TREE_CODE (orig_op1) == INTEGER_CST 3347 && int_fits_type_p (orig_op1, c_common_signed_type 3348 (result_type))) 3349 || (op1_signed && TREE_CODE (orig_op0) == INTEGER_CST 3350 && int_fits_type_p (orig_op0, c_common_signed_type 3351 (result_type))))) 3352 /* OK */; 3353 else 3354 warning ("comparison between signed and unsigned integer expressions"); 3355 3356 /* Warn if two unsigned values are being compared in a size 3357 larger than their original size, and one (and only one) is the 3358 result of a `~' operator. This comparison will always fail. 3359 3360 Also warn if one operand is a constant, and the constant does not 3361 have all bits set that are set in the ~ operand when it is 3362 extended. */ 3363 3364 if ((TREE_CODE (primop0) == BIT_NOT_EXPR) 3365 ^ (TREE_CODE (primop1) == BIT_NOT_EXPR)) 3366 { 3367 if (TREE_CODE (primop0) == BIT_NOT_EXPR) 3368 primop0 = get_narrower (TREE_OPERAND (op0, 0), &unsignedp0); 3369 if (TREE_CODE (primop1) == BIT_NOT_EXPR) 3370 primop1 = get_narrower (TREE_OPERAND (op1, 0), &unsignedp1); 3371 3372 if (host_integerp (primop0, 0) || host_integerp (primop1, 0)) 3373 { 3374 tree primop; 3375 HOST_WIDE_INT constant, mask; 3376 int unsignedp; 3377 unsigned int bits; 3378 3379 if (host_integerp (primop0, 0)) 3380 { 3381 primop = primop1; 3382 unsignedp = unsignedp1; 3383 constant = tree_low_cst (primop0, 0); 3384 } 3385 else 3386 { 3387 primop = primop0; 3388 unsignedp = unsignedp0; 3389 constant = tree_low_cst (primop1, 0); 3390 } 3391 3392 bits = TYPE_PRECISION (TREE_TYPE (primop)); 3393 if (bits < TYPE_PRECISION (result_type) 3394 && bits < HOST_BITS_PER_LONG && unsignedp) 3395 { 3396 mask = (~ (HOST_WIDE_INT) 0) << bits; 3397 if ((mask & constant) != mask) 3398 warning ("comparison of promoted ~unsigned with constant"); 3399 } 3400 } 3401 else if (unsignedp0 && unsignedp1 3402 && (TYPE_PRECISION (TREE_TYPE (primop0)) 3403 < TYPE_PRECISION (result_type)) 3404 && (TYPE_PRECISION (TREE_TYPE (primop1)) 3405 < TYPE_PRECISION (result_type))) 3406 warning ("comparison of promoted ~unsigned with unsigned"); 3407 } 3408 } 3409 } 3410 3411 /* At this point, RESULT_TYPE must be nonzero to avoid an error message. 3412 If CONVERTED is zero, both args will be converted to type RESULT_TYPE. 3413 Then the expression will be built. 3414 It will be given type FINAL_TYPE if that is nonzero; 3415 otherwise, it will be given type RESULT_TYPE. */ 3416 3417 if (!result_type) 3418 { 3419 error ("invalid operands of types `%T' and `%T' to binary `%O'", 3420 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1), code); 3421 return error_mark_node; 3422 } 3423 3424 /* Issue warnings about peculiar, but valid, uses of NULL. */ 3425 if (/* It's reasonable to use pointer values as operands of && 3426 and ||, so NULL is no exception. */ 3427 !(code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR) 3428 && (/* If OP0 is NULL and OP1 is not a pointer, or vice versa. */ 3429 (orig_op0 == null_node 3430 && TREE_CODE (TREE_TYPE (op1)) != POINTER_TYPE) 3431 /* Or vice versa. */ 3432 || (orig_op1 == null_node 3433 && TREE_CODE (TREE_TYPE (op0)) != POINTER_TYPE) 3434 /* Or, both are NULL and the operation was not a comparison. */ 3435 || (orig_op0 == null_node && orig_op1 == null_node 3436 && code != EQ_EXPR && code != NE_EXPR))) 3437 /* Some sort of arithmetic operation involving NULL was 3438 performed. Note that pointer-difference and pointer-addition 3439 have already been handled above, and so we don't end up here in 3440 that case. */ 3441 warning ("NULL used in arithmetic"); 3442 3443 if (! converted) 3444 { 3445 if (TREE_TYPE (op0) != result_type) 3446 op0 = cp_convert (result_type, op0); 3447 if (TREE_TYPE (op1) != result_type) 3448 op1 = cp_convert (result_type, op1); 3449 3450 if (op0 == error_mark_node || op1 == error_mark_node) 3451 return error_mark_node; 3452 } 3453 3454 if (build_type == NULL_TREE) 3455 build_type = result_type; 3456 3457 { 3458 tree result = build (resultcode, build_type, op0, op1); 3459 tree folded; 3460 3461 folded = fold_if_not_in_template (result); 3462 if (folded == result) 3463 TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1); 3464 if (final_type != 0) 3465 return cp_convert (final_type, folded); 3466 return folded; 3467 } 3468} 3469 3470/* Return a tree for the sum or difference (RESULTCODE says which) 3471 of pointer PTROP and integer INTOP. */ 3472 3473static tree 3474cp_pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop) 3475{ 3476 tree res_type = TREE_TYPE (ptrop); 3477 3478 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type) 3479 in certain circumstance (when it's valid to do so). So we need 3480 to make sure it's complete. We don't need to check here, if we 3481 can actually complete it at all, as those checks will be done in 3482 pointer_int_sum() anyway. */ 3483 complete_type (TREE_TYPE (res_type)); 3484 3485 return pointer_int_sum (resultcode, ptrop, fold (intop)); 3486} 3487 3488/* Return a tree for the difference of pointers OP0 and OP1. 3489 The resulting tree has type int. */ 3490 3491static tree 3492pointer_diff (tree op0, tree op1, tree ptrtype) 3493{ 3494 tree result, folded; 3495 tree restype = ptrdiff_type_node; 3496 tree target_type = TREE_TYPE (ptrtype); 3497 3498 if (!complete_type_or_else (target_type, NULL_TREE)) 3499 return error_mark_node; 3500 3501 if (pedantic || warn_pointer_arith) 3502 { 3503 if (TREE_CODE (target_type) == VOID_TYPE) 3504 pedwarn ("ISO C++ forbids using pointer of type `void *' in subtraction"); 3505 if (TREE_CODE (target_type) == FUNCTION_TYPE) 3506 pedwarn ("ISO C++ forbids using pointer to a function in subtraction"); 3507 if (TREE_CODE (target_type) == METHOD_TYPE) 3508 pedwarn ("ISO C++ forbids using pointer to a method in subtraction"); 3509 } 3510 3511 /* First do the subtraction as integers; 3512 then drop through to build the divide operator. */ 3513 3514 op0 = cp_build_binary_op (MINUS_EXPR, 3515 cp_convert (restype, op0), 3516 cp_convert (restype, op1)); 3517 3518 /* This generates an error if op1 is a pointer to an incomplete type. */ 3519 if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (op1)))) 3520 error ("invalid use of a pointer to an incomplete type in pointer arithmetic"); 3521 3522 op1 = (TYPE_PTROB_P (ptrtype) 3523 ? size_in_bytes (target_type) 3524 : integer_one_node); 3525 3526 /* Do the division. */ 3527 3528 result = build (EXACT_DIV_EXPR, restype, op0, cp_convert (restype, op1)); 3529 3530 folded = fold (result); 3531 if (folded == result) 3532 TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1); 3533 return folded; 3534} 3535 3536/* Construct and perhaps optimize a tree representation 3537 for a unary operation. CODE, a tree_code, specifies the operation 3538 and XARG is the operand. */ 3539 3540tree 3541build_x_unary_op (enum tree_code code, tree xarg) 3542{ 3543 tree orig_expr = xarg; 3544 tree exp; 3545 int ptrmem = 0; 3546 3547 if (processing_template_decl) 3548 { 3549 if (type_dependent_expression_p (xarg)) 3550 return build_min_nt (code, xarg, NULL_TREE); 3551 3552 xarg = build_non_dependent_expr (xarg); 3553 } 3554 3555 exp = NULL_TREE; 3556 3557 /* [expr.unary.op] says: 3558 3559 The address of an object of incomplete type can be taken. 3560 3561 (And is just the ordinary address operator, not an overloaded 3562 "operator &".) However, if the type is a template 3563 specialization, we must complete the type at this point so that 3564 an overloaded "operator &" will be available if required. */ 3565 if (code == ADDR_EXPR 3566 && TREE_CODE (xarg) != TEMPLATE_ID_EXPR 3567 && ((CLASS_TYPE_P (TREE_TYPE (xarg)) 3568 && !COMPLETE_TYPE_P (complete_type (TREE_TYPE (xarg)))) 3569 || (TREE_CODE (xarg) == OFFSET_REF))) 3570 /* Don't look for a function. */; 3571 else 3572 exp = build_new_op (code, LOOKUP_NORMAL, xarg, NULL_TREE, NULL_TREE, 3573 /*overloaded_p=*/NULL); 3574 if (!exp && code == ADDR_EXPR) 3575 { 3576 /* A pointer to member-function can be formed only by saying 3577 &X::mf. */ 3578 if (!flag_ms_extensions && TREE_CODE (TREE_TYPE (xarg)) == METHOD_TYPE 3579 && (TREE_CODE (xarg) != OFFSET_REF || !PTRMEM_OK_P (xarg))) 3580 { 3581 if (TREE_CODE (xarg) != OFFSET_REF) 3582 { 3583 error ("invalid use of '%E' to form a pointer-to-member-function. Use a qualified-id.", 3584 xarg); 3585 return error_mark_node; 3586 } 3587 else 3588 { 3589 error ("parenthesis around '%E' cannot be used to form a pointer-to-member-function", 3590 xarg); 3591 PTRMEM_OK_P (xarg) = 1; 3592 } 3593 } 3594 3595 if (TREE_CODE (xarg) == OFFSET_REF) 3596 { 3597 ptrmem = PTRMEM_OK_P (xarg); 3598 3599 if (!ptrmem && !flag_ms_extensions 3600 && TREE_CODE (TREE_TYPE (TREE_OPERAND (xarg, 1))) == METHOD_TYPE) 3601 { 3602 /* A single non-static member, make sure we don't allow a 3603 pointer-to-member. */ 3604 xarg = build (OFFSET_REF, TREE_TYPE (xarg), 3605 TREE_OPERAND (xarg, 0), 3606 ovl_cons (TREE_OPERAND (xarg, 1), NULL_TREE)); 3607 PTRMEM_OK_P (xarg) = ptrmem; 3608 } 3609 } 3610 else if (TREE_CODE (xarg) == TARGET_EXPR) 3611 warning ("taking address of temporary"); 3612 exp = build_unary_op (ADDR_EXPR, xarg, 0); 3613 } 3614 3615 if (processing_template_decl && exp != error_mark_node) 3616 exp = build_min_non_dep (code, exp, orig_expr, 3617 /*For {PRE,POST}{INC,DEC}REMENT_EXPR*/NULL_TREE); 3618 if (TREE_CODE (exp) == ADDR_EXPR) 3619 PTRMEM_OK_P (exp) = ptrmem; 3620 return exp; 3621} 3622 3623/* Like c_common_truthvalue_conversion, but handle pointer-to-member 3624 constants, where a null value is represented by an INTEGER_CST of 3625 -1. */ 3626 3627tree 3628cp_truthvalue_conversion (tree expr) 3629{ 3630 tree type = TREE_TYPE (expr); 3631 if (TYPE_PTRMEM_P (type)) 3632 return build_binary_op (NE_EXPR, expr, integer_zero_node, 1); 3633 else 3634 return c_common_truthvalue_conversion (expr); 3635} 3636 3637/* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */ 3638 3639tree 3640condition_conversion (tree expr) 3641{ 3642 tree t; 3643 if (processing_template_decl) 3644 return expr; 3645 t = perform_implicit_conversion (boolean_type_node, expr); 3646 t = fold (build1 (CLEANUP_POINT_EXPR, boolean_type_node, t)); 3647 return t; 3648} 3649 3650/* Return an ADDR_EXPR giving the address of T. This function 3651 attempts no optimizations or simplifications; it is a low-level 3652 primitive. */ 3653 3654tree 3655build_address (tree t) 3656{ 3657 tree addr; 3658 3659 if (error_operand_p (t) || !cxx_mark_addressable (t)) 3660 return error_mark_node; 3661 3662 addr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (t)), t); 3663 if (staticp (t)) 3664 TREE_CONSTANT (addr) = 1; 3665 3666 return addr; 3667} 3668 3669/* Return a NOP_EXPR converting EXPR to TYPE. */ 3670 3671tree 3672build_nop (tree type, tree expr) 3673{ 3674 tree nop; 3675 3676 if (type == error_mark_node || error_operand_p (expr)) 3677 return expr; 3678 3679 nop = build1 (NOP_EXPR, type, expr); 3680 if (TREE_CONSTANT (expr)) 3681 TREE_CONSTANT (nop) = 1; 3682 3683 return nop; 3684} 3685 3686/* C++: Must handle pointers to members. 3687 3688 Perhaps type instantiation should be extended to handle conversion 3689 from aggregates to types we don't yet know we want? (Or are those 3690 cases typically errors which should be reported?) 3691 3692 NOCONVERT nonzero suppresses the default promotions 3693 (such as from short to int). */ 3694 3695tree 3696build_unary_op (enum tree_code code, tree xarg, int noconvert) 3697{ 3698 /* No default_conversion here. It causes trouble for ADDR_EXPR. */ 3699 tree arg = xarg; 3700 tree argtype = 0; 3701 const char *errstring = NULL; 3702 tree val; 3703 3704 if (arg == error_mark_node) 3705 return error_mark_node; 3706 3707 switch (code) 3708 { 3709 case CONVERT_EXPR: 3710 /* This is used for unary plus, because a CONVERT_EXPR 3711 is enough to prevent anybody from looking inside for 3712 associativity, but won't generate any code. */ 3713 if (!(arg = build_expr_type_conversion 3714 (WANT_ARITH | WANT_ENUM | WANT_POINTER, arg, true))) 3715 errstring = "wrong type argument to unary plus"; 3716 else 3717 { 3718 if (!noconvert) 3719 arg = default_conversion (arg); 3720 arg = build1 (NON_LVALUE_EXPR, TREE_TYPE (arg), arg); 3721 TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0)); 3722 } 3723 break; 3724 3725 case NEGATE_EXPR: 3726 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true))) 3727 errstring = "wrong type argument to unary minus"; 3728 else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg))) 3729 arg = perform_integral_promotions (arg); 3730 break; 3731 3732 case BIT_NOT_EXPR: 3733 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 3734 { 3735 code = CONJ_EXPR; 3736 if (!noconvert) 3737 arg = default_conversion (arg); 3738 } 3739 else if (!(arg = build_expr_type_conversion (WANT_INT | WANT_ENUM, 3740 arg, true))) 3741 errstring = "wrong type argument to bit-complement"; 3742 else if (!noconvert) 3743 arg = perform_integral_promotions (arg); 3744 break; 3745 3746 case ABS_EXPR: 3747 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true))) 3748 errstring = "wrong type argument to abs"; 3749 else if (!noconvert) 3750 arg = default_conversion (arg); 3751 break; 3752 3753 case CONJ_EXPR: 3754 /* Conjugating a real value is a no-op, but allow it anyway. */ 3755 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true))) 3756 errstring = "wrong type argument to conjugation"; 3757 else if (!noconvert) 3758 arg = default_conversion (arg); 3759 break; 3760 3761 case TRUTH_NOT_EXPR: 3762 arg = perform_implicit_conversion (boolean_type_node, arg); 3763 val = invert_truthvalue (arg); 3764 if (arg != error_mark_node) 3765 return val; 3766 errstring = "in argument to unary !"; 3767 break; 3768 3769 case NOP_EXPR: 3770 break; 3771 3772 case REALPART_EXPR: 3773 if (TREE_CODE (arg) == COMPLEX_CST) 3774 return TREE_REALPART (arg); 3775 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 3776 return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg)); 3777 else 3778 return arg; 3779 3780 case IMAGPART_EXPR: 3781 if (TREE_CODE (arg) == COMPLEX_CST) 3782 return TREE_IMAGPART (arg); 3783 else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 3784 return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg)); 3785 else 3786 return cp_convert (TREE_TYPE (arg), integer_zero_node); 3787 3788 case PREINCREMENT_EXPR: 3789 case POSTINCREMENT_EXPR: 3790 case PREDECREMENT_EXPR: 3791 case POSTDECREMENT_EXPR: 3792 /* Handle complex lvalues (when permitted) 3793 by reduction to simpler cases. */ 3794 3795 val = unary_complex_lvalue (code, arg); 3796 if (val != 0) 3797 return val; 3798 3799 /* Increment or decrement the real part of the value, 3800 and don't change the imaginary part. */ 3801 if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE) 3802 { 3803 tree real, imag; 3804 3805 arg = stabilize_reference (arg); 3806 real = build_unary_op (REALPART_EXPR, arg, 1); 3807 imag = build_unary_op (IMAGPART_EXPR, arg, 1); 3808 return build (COMPLEX_EXPR, TREE_TYPE (arg), 3809 build_unary_op (code, real, 1), imag); 3810 } 3811 3812 /* Report invalid types. */ 3813 3814 if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_POINTER, 3815 arg, true))) 3816 { 3817 if (code == PREINCREMENT_EXPR) 3818 errstring ="no pre-increment operator for type"; 3819 else if (code == POSTINCREMENT_EXPR) 3820 errstring ="no post-increment operator for type"; 3821 else if (code == PREDECREMENT_EXPR) 3822 errstring ="no pre-decrement operator for type"; 3823 else 3824 errstring ="no post-decrement operator for type"; 3825 break; 3826 } 3827 3828 /* Report something read-only. */ 3829 3830 if (CP_TYPE_CONST_P (TREE_TYPE (arg)) 3831 || TREE_READONLY (arg)) 3832 readonly_error (arg, ((code == PREINCREMENT_EXPR 3833 || code == POSTINCREMENT_EXPR) 3834 ? "increment" : "decrement"), 3835 0); 3836 3837 { 3838 tree inc; 3839 tree result_type = TREE_TYPE (arg); 3840 3841 arg = get_unwidened (arg, 0); 3842 argtype = TREE_TYPE (arg); 3843 3844 /* ARM $5.2.5 last annotation says this should be forbidden. */ 3845 if (TREE_CODE (argtype) == ENUMERAL_TYPE) 3846 pedwarn ("ISO C++ forbids %sing an enum", 3847 (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR) 3848 ? "increment" : "decrement"); 3849 3850 /* Compute the increment. */ 3851 3852 if (TREE_CODE (argtype) == POINTER_TYPE) 3853 { 3854 tree type = complete_type (TREE_TYPE (argtype)); 3855 3856 if (!COMPLETE_OR_VOID_TYPE_P (type)) 3857 error ("cannot %s a pointer to incomplete type `%T'", 3858 ((code == PREINCREMENT_EXPR 3859 || code == POSTINCREMENT_EXPR) 3860 ? "increment" : "decrement"), TREE_TYPE (argtype)); 3861 else if ((pedantic || warn_pointer_arith) 3862 && !TYPE_PTROB_P (argtype)) 3863 pedwarn ("ISO C++ forbids %sing a pointer of type `%T'", 3864 ((code == PREINCREMENT_EXPR 3865 || code == POSTINCREMENT_EXPR) 3866 ? "increment" : "decrement"), argtype); 3867 inc = cxx_sizeof_nowarn (TREE_TYPE (argtype)); 3868 } 3869 else 3870 inc = integer_one_node; 3871 3872 inc = cp_convert (argtype, inc); 3873 3874 /* Handle incrementing a cast-expression. */ 3875 3876 switch (TREE_CODE (arg)) 3877 { 3878 case NOP_EXPR: 3879 case CONVERT_EXPR: 3880 case FLOAT_EXPR: 3881 case FIX_TRUNC_EXPR: 3882 case FIX_FLOOR_EXPR: 3883 case FIX_ROUND_EXPR: 3884 case FIX_CEIL_EXPR: 3885 { 3886 tree incremented, modify, value, compound; 3887 if (! lvalue_p (arg) && pedantic) 3888 pedwarn ("cast to non-reference type used as lvalue"); 3889 arg = stabilize_reference (arg); 3890 if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) 3891 value = arg; 3892 else 3893 value = save_expr (arg); 3894 incremented = build (((code == PREINCREMENT_EXPR 3895 || code == POSTINCREMENT_EXPR) 3896 ? PLUS_EXPR : MINUS_EXPR), 3897 argtype, value, inc); 3898 3899 modify = build_modify_expr (arg, NOP_EXPR, incremented); 3900 compound = build (COMPOUND_EXPR, TREE_TYPE (arg), modify, value); 3901 3902 /* Eliminate warning about unused result of + or -. */ 3903 TREE_NO_UNUSED_WARNING (compound) = 1; 3904 return compound; 3905 } 3906 3907 default: 3908 break; 3909 } 3910 3911 /* Complain about anything else that is not a true lvalue. */ 3912 if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR 3913 || code == POSTINCREMENT_EXPR) 3914 ? "increment" : "decrement"))) 3915 return error_mark_node; 3916 3917 /* Forbid using -- on `bool'. */ 3918 if (TREE_TYPE (arg) == boolean_type_node) 3919 { 3920 if (code == POSTDECREMENT_EXPR || code == PREDECREMENT_EXPR) 3921 { 3922 error ("invalid use of `--' on bool variable `%D'", arg); 3923 return error_mark_node; 3924 } 3925 val = boolean_increment (code, arg); 3926 } 3927 else 3928 val = build (code, TREE_TYPE (arg), arg, inc); 3929 3930 TREE_SIDE_EFFECTS (val) = 1; 3931 return cp_convert (result_type, val); 3932 } 3933 3934 case ADDR_EXPR: 3935 /* Note that this operation never does default_conversion 3936 regardless of NOCONVERT. */ 3937 3938 argtype = lvalue_type (arg); 3939 3940 if (TREE_CODE (arg) == OFFSET_REF) 3941 goto offset_ref; 3942 3943 if (TREE_CODE (argtype) == REFERENCE_TYPE) 3944 { 3945 arg = build1 3946 (CONVERT_EXPR, 3947 build_pointer_type (TREE_TYPE (argtype)), arg); 3948 TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0)); 3949 return arg; 3950 } 3951 else if (pedantic && DECL_MAIN_P (arg)) 3952 /* ARM $3.4 */ 3953 pedwarn ("ISO C++ forbids taking address of function `::main'"); 3954 3955 /* Let &* cancel out to simplify resulting code. */ 3956 if (TREE_CODE (arg) == INDIRECT_REF) 3957 { 3958 /* We don't need to have `current_class_ptr' wrapped in a 3959 NON_LVALUE_EXPR node. */ 3960 if (arg == current_class_ref) 3961 return current_class_ptr; 3962 3963 arg = TREE_OPERAND (arg, 0); 3964 if (TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE) 3965 { 3966 arg = build1 3967 (CONVERT_EXPR, 3968 build_pointer_type (TREE_TYPE (TREE_TYPE (arg))), arg); 3969 TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0)); 3970 } 3971 else if (lvalue_p (arg)) 3972 /* Don't let this be an lvalue. */ 3973 return non_lvalue (arg); 3974 return arg; 3975 } 3976 3977 /* For &x[y], return x+y. But, in a template, ARG may be an 3978 ARRAY_REF representing a non-dependent expression. In that 3979 case, there may be an overloaded "operator []" that will be 3980 chosen at instantiation time; we must not try to optimize 3981 here. */ 3982 if (TREE_CODE (arg) == ARRAY_REF && !processing_template_decl) 3983 { 3984 if (!cxx_mark_addressable (TREE_OPERAND (arg, 0))) 3985 return error_mark_node; 3986 return cp_build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0), 3987 TREE_OPERAND (arg, 1)); 3988 } 3989 3990 /* Uninstantiated types are all functions. Taking the 3991 address of a function is a no-op, so just return the 3992 argument. */ 3993 3994 if (TREE_CODE (arg) == IDENTIFIER_NODE 3995 && IDENTIFIER_OPNAME_P (arg)) 3996 { 3997 abort (); 3998 /* We don't know the type yet, so just work around the problem. 3999 We know that this will resolve to an lvalue. */ 4000 return build1 (ADDR_EXPR, unknown_type_node, arg); 4001 } 4002 4003 if (TREE_CODE (arg) == COMPONENT_REF && type_unknown_p (arg) 4004 && !really_overloaded_fn (TREE_OPERAND (arg, 1))) 4005 { 4006 /* They're trying to take the address of a unique non-static 4007 member function. This is ill-formed (except in MS-land), 4008 but let's try to DTRT. 4009 Note: We only handle unique functions here because we don't 4010 want to complain if there's a static overload; non-unique 4011 cases will be handled by instantiate_type. But we need to 4012 handle this case here to allow casts on the resulting PMF. 4013 We could defer this in non-MS mode, but it's easier to give 4014 a useful error here. */ 4015 4016 /* Inside constant member functions, the `this' pointer 4017 contains an extra const qualifier. TYPE_MAIN_VARIANT 4018 is used here to remove this const from the diagnostics 4019 and the created OFFSET_REF. */ 4020 tree base = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (arg, 0))); 4021 tree name = DECL_NAME (get_first_fn (TREE_OPERAND (arg, 1))); 4022 4023 if (! flag_ms_extensions) 4024 { 4025 if (current_class_type 4026 && TREE_OPERAND (arg, 0) == current_class_ref) 4027 /* An expression like &memfn. */ 4028 pedwarn ("ISO C++ forbids taking the address of an unqualified" 4029 " or parenthesized non-static member function to form" 4030 " a pointer to member function. Say `&%T::%D'", 4031 base, name); 4032 else 4033 pedwarn ("ISO C++ forbids taking the address of a bound member" 4034 " function to form a pointer to member function." 4035 " Say `&%T::%D'", 4036 base, name); 4037 } 4038 arg = build_offset_ref (base, name, /*address_p=*/true); 4039 } 4040 4041 offset_ref: 4042 if (type_unknown_p (arg)) 4043 return build1 (ADDR_EXPR, unknown_type_node, arg); 4044 4045 /* Handle complex lvalues (when permitted) 4046 by reduction to simpler cases. */ 4047 val = unary_complex_lvalue (code, arg); 4048 if (val != 0) 4049 return val; 4050 4051 switch (TREE_CODE (arg)) 4052 { 4053 case NOP_EXPR: 4054 case CONVERT_EXPR: 4055 case FLOAT_EXPR: 4056 case FIX_TRUNC_EXPR: 4057 case FIX_FLOOR_EXPR: 4058 case FIX_ROUND_EXPR: 4059 case FIX_CEIL_EXPR: 4060 if (! lvalue_p (arg) && pedantic) 4061 pedwarn ("ISO C++ forbids taking the address of a cast to a non-lvalue expression"); 4062 break; 4063 4064 case OVERLOAD: 4065 arg = OVL_CURRENT (arg); 4066 break; 4067 4068 default: 4069 break; 4070 } 4071 4072 /* Allow the address of a constructor if all the elements 4073 are constant. */ 4074 if (TREE_CODE (arg) == CONSTRUCTOR && TREE_HAS_CONSTRUCTOR (arg) 4075 && TREE_CONSTANT (arg)) 4076 ; 4077 /* Anything not already handled and not a true memory reference 4078 is an error. */ 4079 else if (TREE_CODE (argtype) != FUNCTION_TYPE 4080 && TREE_CODE (argtype) != METHOD_TYPE 4081 && TREE_CODE (arg) != OFFSET_REF 4082 && !lvalue_or_else (arg, "unary `&'")) 4083 return error_mark_node; 4084 4085 if (argtype != error_mark_node) 4086 argtype = build_pointer_type (argtype); 4087 4088 { 4089 tree addr; 4090 4091 if (TREE_CODE (arg) != COMPONENT_REF 4092 /* Inside a template, we are processing a non-dependent 4093 expression so we can just form an ADDR_EXPR with the 4094 correct type. */ 4095 || processing_template_decl) 4096 { 4097 addr = build_address (arg); 4098 if (TREE_CODE (arg) == OFFSET_REF) 4099 PTRMEM_OK_P (addr) = PTRMEM_OK_P (arg); 4100 } 4101 else if (TREE_CODE (TREE_OPERAND (arg, 1)) == BASELINK) 4102 { 4103 tree fn = BASELINK_FUNCTIONS (TREE_OPERAND (arg, 1)); 4104 4105 /* We can only get here with a single static member 4106 function. */ 4107 my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL 4108 && DECL_STATIC_FUNCTION_P (fn), 4109 20030906); 4110 mark_used (fn); 4111 addr = build_address (fn); 4112 if (TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0))) 4113 /* Do not lose object's side effects. */ 4114 addr = build (COMPOUND_EXPR, TREE_TYPE (addr), 4115 TREE_OPERAND (arg, 0), addr); 4116 } 4117 else if (DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1))) 4118 { 4119 error ("attempt to take address of bit-field structure member `%D'", 4120 TREE_OPERAND (arg, 1)); 4121 return error_mark_node; 4122 } 4123 else 4124 { 4125 /* Unfortunately we cannot just build an address 4126 expression here, because we would not handle 4127 address-constant-expressions or offsetof correctly. */ 4128 tree field = TREE_OPERAND (arg, 1); 4129 tree rval = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), 0); 4130 tree binfo = lookup_base (TREE_TYPE (TREE_TYPE (rval)), 4131 decl_type_context (field), 4132 ba_check, NULL); 4133 4134 rval = build_base_path (PLUS_EXPR, rval, binfo, 1); 4135 rval = build_nop (argtype, rval); 4136 addr = fold (build (PLUS_EXPR, argtype, rval, 4137 cp_convert (argtype, byte_position (field)))); 4138 } 4139 4140 if (TREE_CODE (argtype) == POINTER_TYPE 4141 && TREE_CODE (TREE_TYPE (argtype)) == METHOD_TYPE) 4142 { 4143 build_ptrmemfunc_type (argtype); 4144 addr = build_ptrmemfunc (argtype, addr, 0); 4145 } 4146 4147 return addr; 4148 } 4149 4150 default: 4151 break; 4152 } 4153 4154 if (!errstring) 4155 { 4156 if (argtype == 0) 4157 argtype = TREE_TYPE (arg); 4158 return fold (build1 (code, argtype, arg)); 4159 } 4160 4161 error ("%s", errstring); 4162 return error_mark_node; 4163} 4164 4165/* Apply unary lvalue-demanding operator CODE to the expression ARG 4166 for certain kinds of expressions which are not really lvalues 4167 but which we can accept as lvalues. 4168 4169 If ARG is not a kind of expression we can handle, return 4170 NULL_TREE. */ 4171 4172tree 4173unary_complex_lvalue (enum tree_code code, tree arg) 4174{ 4175 /* Handle (a, b) used as an "lvalue". */ 4176 if (TREE_CODE (arg) == COMPOUND_EXPR) 4177 { 4178 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 1), 0); 4179 return build (COMPOUND_EXPR, TREE_TYPE (real_result), 4180 TREE_OPERAND (arg, 0), real_result); 4181 } 4182 4183 /* Handle (a ? b : c) used as an "lvalue". */ 4184 if (TREE_CODE (arg) == COND_EXPR 4185 || TREE_CODE (arg) == MIN_EXPR || TREE_CODE (arg) == MAX_EXPR) 4186 return rationalize_conditional_expr (code, arg); 4187 4188 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */ 4189 if (TREE_CODE (arg) == MODIFY_EXPR 4190 || TREE_CODE (arg) == PREINCREMENT_EXPR 4191 || TREE_CODE (arg) == PREDECREMENT_EXPR) 4192 { 4193 tree lvalue = TREE_OPERAND (arg, 0); 4194 if (TREE_SIDE_EFFECTS (lvalue)) 4195 { 4196 lvalue = stabilize_reference (lvalue); 4197 arg = build (TREE_CODE (arg), TREE_TYPE (arg), 4198 lvalue, TREE_OPERAND (arg, 1)); 4199 } 4200 return unary_complex_lvalue 4201 (code, build (COMPOUND_EXPR, TREE_TYPE (lvalue), arg, lvalue)); 4202 } 4203 4204 if (code != ADDR_EXPR) 4205 return 0; 4206 4207 /* Handle (a = b) used as an "lvalue" for `&'. */ 4208 if (TREE_CODE (arg) == MODIFY_EXPR 4209 || TREE_CODE (arg) == INIT_EXPR) 4210 { 4211 tree real_result = build_unary_op (code, TREE_OPERAND (arg, 0), 0); 4212 arg = build (COMPOUND_EXPR, TREE_TYPE (real_result), arg, real_result); 4213 TREE_NO_UNUSED_WARNING (arg) = 1; 4214 return arg; 4215 } 4216 4217 if (TREE_CODE (TREE_TYPE (arg)) == FUNCTION_TYPE 4218 || TREE_CODE (TREE_TYPE (arg)) == METHOD_TYPE 4219 || TREE_CODE (arg) == OFFSET_REF) 4220 { 4221 tree t; 4222 4223 my_friendly_assert (TREE_CODE (arg) != SCOPE_REF, 313); 4224 4225 if (TREE_CODE (arg) != OFFSET_REF) 4226 return 0; 4227 4228 t = TREE_OPERAND (arg, 1); 4229 4230 /* Check all this code for right semantics. */ 4231 if (TREE_CODE (t) == FUNCTION_DECL) 4232 { 4233 if (DECL_DESTRUCTOR_P (t)) 4234 error ("taking address of destructor"); 4235 return build_unary_op (ADDR_EXPR, t, 0); 4236 } 4237 if (TREE_CODE (t) == VAR_DECL) 4238 return build_unary_op (ADDR_EXPR, t, 0); 4239 else 4240 { 4241 tree type; 4242 4243 if (TREE_OPERAND (arg, 0) 4244 && ! is_dummy_object (TREE_OPERAND (arg, 0)) 4245 && TREE_CODE (t) != FIELD_DECL) 4246 { 4247 error ("taking address of bound pointer-to-member expression"); 4248 return error_mark_node; 4249 } 4250 if (!PTRMEM_OK_P (arg)) 4251 return build_unary_op (code, arg, 0); 4252 4253 if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) 4254 { 4255 error ("cannot create pointer to reference member `%D'", t); 4256 return error_mark_node; 4257 } 4258 4259 type = build_ptrmem_type (context_for_name_lookup (t), 4260 TREE_TYPE (t)); 4261 t = make_ptrmem_cst (type, TREE_OPERAND (arg, 1)); 4262 return t; 4263 } 4264 } 4265 4266 4267 /* We permit compiler to make function calls returning 4268 objects of aggregate type look like lvalues. */ 4269 { 4270 tree targ = arg; 4271 4272 if (TREE_CODE (targ) == SAVE_EXPR) 4273 targ = TREE_OPERAND (targ, 0); 4274 4275 if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (TREE_TYPE (targ))) 4276 { 4277 if (TREE_CODE (arg) == SAVE_EXPR) 4278 targ = arg; 4279 else 4280 targ = build_cplus_new (TREE_TYPE (arg), arg); 4281 return build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (arg)), targ); 4282 } 4283 4284 if (TREE_CODE (arg) == SAVE_EXPR && TREE_CODE (targ) == INDIRECT_REF) 4285 return build (SAVE_EXPR, build_pointer_type (TREE_TYPE (arg)), 4286 TREE_OPERAND (targ, 0), current_function_decl, NULL); 4287 } 4288 4289 /* Don't let anything else be handled specially. */ 4290 return 0; 4291} 4292 4293/* Mark EXP saying that we need to be able to take the 4294 address of it; it should not be allocated in a register. 4295 Value is true if successful. 4296 4297 C++: we do not allow `current_class_ptr' to be addressable. */ 4298 4299bool 4300cxx_mark_addressable (tree exp) 4301{ 4302 tree x = exp; 4303 4304 while (1) 4305 switch (TREE_CODE (x)) 4306 { 4307 case ADDR_EXPR: 4308 case COMPONENT_REF: 4309 case ARRAY_REF: 4310 case REALPART_EXPR: 4311 case IMAGPART_EXPR: 4312 x = TREE_OPERAND (x, 0); 4313 break; 4314 4315 case PARM_DECL: 4316 if (x == current_class_ptr) 4317 { 4318 error ("cannot take the address of `this', which is an rvalue expression"); 4319 TREE_ADDRESSABLE (x) = 1; /* so compiler doesn't die later. */ 4320 return true; 4321 } 4322 /* Fall through. */ 4323 4324 case VAR_DECL: 4325 /* Caller should not be trying to mark initialized 4326 constant fields addressable. */ 4327 my_friendly_assert (DECL_LANG_SPECIFIC (x) == 0 4328 || DECL_IN_AGGR_P (x) == 0 4329 || TREE_STATIC (x) 4330 || DECL_EXTERNAL (x), 314); 4331 /* Fall through. */ 4332 4333 case CONST_DECL: 4334 case RESULT_DECL: 4335 if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x) 4336 && !DECL_ARTIFICIAL (x) && extra_warnings) 4337 warning ("address requested for `%D', which is declared `register'", 4338 x); 4339 TREE_ADDRESSABLE (x) = 1; 4340 put_var_into_stack (x, /*rescan=*/true); 4341 return true; 4342 4343 case FUNCTION_DECL: 4344 TREE_ADDRESSABLE (x) = 1; 4345 TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (x)) = 1; 4346 return true; 4347 4348 case CONSTRUCTOR: 4349 TREE_ADDRESSABLE (x) = 1; 4350 return true; 4351 4352 case TARGET_EXPR: 4353 TREE_ADDRESSABLE (x) = 1; 4354 cxx_mark_addressable (TREE_OPERAND (x, 0)); 4355 return true; 4356 4357 default: 4358 return true; 4359 } 4360} 4361 4362/* Build and return a conditional expression IFEXP ? OP1 : OP2. */ 4363 4364tree 4365build_x_conditional_expr (tree ifexp, tree op1, tree op2) 4366{ 4367 tree orig_ifexp = ifexp; 4368 tree orig_op1 = op1; 4369 tree orig_op2 = op2; 4370 tree expr; 4371 4372 if (processing_template_decl) 4373 { 4374 /* The standard says that the expression is type-dependent if 4375 IFEXP is type-dependent, even though the eventual type of the 4376 expression doesn't dependent on IFEXP. */ 4377 if (type_dependent_expression_p (ifexp) 4378 /* As a GNU extension, the middle operand may be omitted. */ 4379 || (op1 && type_dependent_expression_p (op1)) 4380 || type_dependent_expression_p (op2)) 4381 return build_min_nt (COND_EXPR, ifexp, op1, op2); 4382 ifexp = build_non_dependent_expr (ifexp); 4383 if (op1) 4384 op1 = build_non_dependent_expr (op1); 4385 op2 = build_non_dependent_expr (op2); 4386 } 4387 4388 expr = build_conditional_expr (ifexp, op1, op2); 4389 if (processing_template_decl && expr != error_mark_node) 4390 return build_min_non_dep (COND_EXPR, expr, 4391 orig_ifexp, orig_op1, orig_op2); 4392 return expr; 4393} 4394 4395/* Given a list of expressions, return a compound expression 4396 that performs them all and returns the value of the last of them. */ 4397 4398tree build_x_compound_expr_from_list (tree list, const char *msg) 4399{ 4400 tree expr = TREE_VALUE (list); 4401 4402 if (TREE_CHAIN (list)) 4403 { 4404 if (msg) 4405 pedwarn ("%s expression list treated as compound expression", msg); 4406 4407 for (list = TREE_CHAIN (list); list; list = TREE_CHAIN (list)) 4408 expr = build_x_compound_expr (expr, TREE_VALUE (list)); 4409 } 4410 4411 return expr; 4412} 4413 4414/* Handle overloading of the ',' operator when needed. */ 4415 4416tree 4417build_x_compound_expr (tree op1, tree op2) 4418{ 4419 tree result; 4420 tree orig_op1 = op1; 4421 tree orig_op2 = op2; 4422 4423 if (processing_template_decl) 4424 { 4425 if (type_dependent_expression_p (op1) 4426 || type_dependent_expression_p (op2)) 4427 return build_min_nt (COMPOUND_EXPR, op1, op2); 4428 op1 = build_non_dependent_expr (op1); 4429 op2 = build_non_dependent_expr (op2); 4430 } 4431 4432 result = build_new_op (COMPOUND_EXPR, LOOKUP_NORMAL, op1, op2, NULL_TREE, 4433 /*overloaded_p=*/NULL); 4434 if (!result) 4435 result = build_compound_expr (op1, op2); 4436 4437 if (processing_template_decl && result != error_mark_node) 4438 return build_min_non_dep (COMPOUND_EXPR, result, orig_op1, orig_op2); 4439 4440 return result; 4441} 4442 4443/* Build a compound expression. */ 4444 4445tree 4446build_compound_expr (tree lhs, tree rhs) 4447{ 4448 lhs = decl_constant_value (lhs); 4449 lhs = convert_to_void (lhs, "left-hand operand of comma"); 4450 4451 if (lhs == error_mark_node || rhs == error_mark_node) 4452 return error_mark_node; 4453 4454 if (TREE_CODE (rhs) == TARGET_EXPR) 4455 { 4456 /* If the rhs is a TARGET_EXPR, then build the compound 4457 expression inside the target_expr's initializer. This 4458 helps the compiler to eliminate unnecessary temporaries. */ 4459 tree init = TREE_OPERAND (rhs, 1); 4460 4461 init = build (COMPOUND_EXPR, TREE_TYPE (init), lhs, init); 4462 TREE_OPERAND (rhs, 1) = init; 4463 4464 return rhs; 4465 } 4466 4467 return build (COMPOUND_EXPR, TREE_TYPE (rhs), lhs, rhs); 4468} 4469 4470/* Issue an error message if casting from SRC_TYPE to DEST_TYPE casts 4471 away constness. DESCRIPTION explains what operation is taking 4472 place. */ 4473 4474static void 4475check_for_casting_away_constness (tree src_type, tree dest_type, 4476 const char *description) 4477{ 4478 if (casts_away_constness (src_type, dest_type)) 4479 error ("%s from type `%T' to type `%T' casts away constness", 4480 description, src_type, dest_type); 4481} 4482 4483/* Return an expression representing static_cast<TYPE>(EXPR). */ 4484 4485tree 4486build_static_cast (tree type, tree expr) 4487{ 4488 tree intype; 4489 tree result; 4490 4491 if (type == error_mark_node || expr == error_mark_node) 4492 return error_mark_node; 4493 4494 if (processing_template_decl) 4495 { 4496 expr = build_min (STATIC_CAST_EXPR, type, expr); 4497 /* We don't know if it will or will not have side effects. */ 4498 TREE_SIDE_EFFECTS (expr) = 1; 4499 return expr; 4500 } 4501 4502 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 4503 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 4504 if (TREE_CODE (type) != REFERENCE_TYPE 4505 && TREE_CODE (expr) == NOP_EXPR 4506 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 4507 expr = TREE_OPERAND (expr, 0); 4508 4509 intype = TREE_TYPE (expr); 4510 4511 /* [expr.static.cast] 4512 4513 An lvalue of type "cv1 B", where B is a class type, can be cast 4514 to type "reference to cv2 D", where D is a class derived (clause 4515 _class.derived_) from B, if a valid standard conversion from 4516 "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the 4517 same cv-qualification as, or greater cv-qualification than, cv1, 4518 and B is not a virtual base class of D. */ 4519 /* We check this case before checking the validity of "TYPE t = 4520 EXPR;" below because for this case: 4521 4522 struct B {}; 4523 struct D : public B { D(const B&); }; 4524 extern B& b; 4525 void f() { static_cast<const D&>(b); } 4526 4527 we want to avoid constructing a new D. The standard is not 4528 completely clear about this issue, but our interpretation is 4529 consistent with other compilers. */ 4530 if (TREE_CODE (type) == REFERENCE_TYPE 4531 && CLASS_TYPE_P (TREE_TYPE (type)) 4532 && CLASS_TYPE_P (intype) 4533 && real_lvalue_p (expr) 4534 && DERIVED_FROM_P (intype, TREE_TYPE (type)) 4535 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT (intype)), 4536 build_pointer_type (TYPE_MAIN_VARIANT 4537 (TREE_TYPE (type)))) 4538 && at_least_as_qualified_p (TREE_TYPE (type), intype)) 4539 { 4540 /* There is a standard conversion from "D*" to "B*" even if "B" 4541 is ambiguous or inaccessible. Therefore, we ask lookup_base 4542 to check these conditions. */ 4543 tree base = lookup_base (TREE_TYPE (type), intype, ba_check, NULL); 4544 4545 /* Convert from "B*" to "D*". This function will check that "B" 4546 is not a virtual base of "D". */ 4547 expr = build_base_path (MINUS_EXPR, build_address (expr), 4548 base, /*nonnull=*/false); 4549 /* Convert the pointer to a reference -- but then remember that 4550 there are no expressions with reference type in C++. */ 4551 return convert_from_reference (build_nop (type, expr)); 4552 } 4553 4554 /* [expr.static.cast] 4555 4556 An expression e can be explicitly converted to a type T using a 4557 static_cast of the form static_cast<T>(e) if the declaration T 4558 t(e);" is well-formed, for some invented temporary variable 4559 t. */ 4560 result = perform_direct_initialization_if_possible (type, expr); 4561 if (result) 4562 { 4563 result = convert_from_reference (result); 4564 /* [expr.static.cast] 4565 4566 If T is a reference type, the result is an lvalue; otherwise, 4567 the result is an rvalue. */ 4568 if (TREE_CODE (type) != REFERENCE_TYPE 4569 && real_lvalue_p (result)) 4570 result = build1 (NON_LVALUE_EXPR, TREE_TYPE (result), result); 4571 return result; 4572 } 4573 4574 /* [expr.static.cast] 4575 4576 Any expression can be explicitly converted to type cv void. */ 4577 if (TREE_CODE (type) == VOID_TYPE) 4578 return convert_to_void (expr, /*implicit=*/NULL); 4579 4580 /* [expr.static.cast] 4581 4582 The inverse of any standard conversion sequence (clause _conv_), 4583 other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer 4584 (_conv.array_), function-to-pointer (_conv.func_), and boolean 4585 (_conv.bool_) conversions, can be performed explicitly using 4586 static_cast subject to the restriction that the explicit 4587 conversion does not cast away constness (_expr.const.cast_), and 4588 the following additional rules for specific cases: */ 4589 /* For reference, the conversions not excluded are: integral 4590 promotions, floating point promotion, integral conversions, 4591 floating point conversions, floating-integral conversions, 4592 pointer conversions, and pointer to member conversions. */ 4593 if ((ARITHMETIC_TYPE_P (type) && ARITHMETIC_TYPE_P (intype)) 4594 /* DR 128 4595 4596 A value of integral _or enumeration_ type can be explicitly 4597 converted to an enumeration type. */ 4598 || (INTEGRAL_OR_ENUMERATION_TYPE_P (type) 4599 && INTEGRAL_OR_ENUMERATION_TYPE_P (intype))) 4600 /* Really, build_c_cast should defer to this function rather 4601 than the other way around. */ 4602 return build_c_cast (type, expr); 4603 4604 if (TYPE_PTR_P (type) && TYPE_PTR_P (intype) 4605 && CLASS_TYPE_P (TREE_TYPE (type)) 4606 && CLASS_TYPE_P (TREE_TYPE (intype)) 4607 && can_convert (build_pointer_type (TYPE_MAIN_VARIANT 4608 (TREE_TYPE (intype))), 4609 build_pointer_type (TYPE_MAIN_VARIANT 4610 (TREE_TYPE (type))))) 4611 { 4612 tree base; 4613 4614 check_for_casting_away_constness (intype, type, "static_cast"); 4615 base = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), ba_check, 4616 NULL); 4617 return build_base_path (MINUS_EXPR, expr, base, /*nonnull=*/false); 4618 } 4619 4620 if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) 4621 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) 4622 { 4623 tree c1; 4624 tree c2; 4625 tree t1; 4626 tree t2; 4627 4628 c1 = TYPE_PTRMEM_CLASS_TYPE (intype); 4629 c2 = TYPE_PTRMEM_CLASS_TYPE (type); 4630 4631 if (TYPE_PTRMEM_P (type)) 4632 { 4633 t1 = (build_ptrmem_type 4634 (c1, 4635 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (intype)))); 4636 t2 = (build_ptrmem_type 4637 (c2, 4638 TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (type)))); 4639 } 4640 else 4641 { 4642 t1 = intype; 4643 t2 = type; 4644 } 4645 if (can_convert (t1, t2)) 4646 { 4647 check_for_casting_away_constness (intype, type, "static_cast"); 4648 if (TYPE_PTRMEM_P (type)) 4649 { 4650 tree delta; 4651 4652 if (TREE_CODE (expr) == PTRMEM_CST) 4653 expr = cplus_expand_constant (expr); 4654 delta = get_delta_difference (c1, c2, /*force=*/1); 4655 if (!integer_zerop (delta)) 4656 expr = cp_build_binary_op (PLUS_EXPR, 4657 build_nop (ptrdiff_type_node, expr), 4658 delta); 4659 return build_nop (type, expr); 4660 } 4661 else 4662 return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 4663 /*force=*/1); 4664 } 4665 } 4666 4667 /* [expr.static.cast] 4668 4669 An rvalue of type "pointer to cv void" can be explicitly 4670 converted to a pointer to object type. A value of type pointer 4671 to object converted to "pointer to cv void" and back to the 4672 original pointer type will have its original value. */ 4673 if (TREE_CODE (intype) == POINTER_TYPE 4674 && VOID_TYPE_P (TREE_TYPE (intype)) 4675 && TYPE_PTROB_P (type)) 4676 { 4677 check_for_casting_away_constness (intype, type, "static_cast"); 4678 return build_nop (type, expr); 4679 } 4680 4681 error ("invalid static_cast from type `%T' to type `%T'", intype, type); 4682 return error_mark_node; 4683} 4684 4685tree 4686build_reinterpret_cast (tree type, tree expr) 4687{ 4688 tree intype; 4689 4690 if (type == error_mark_node || expr == error_mark_node) 4691 return error_mark_node; 4692 4693 if (processing_template_decl) 4694 { 4695 tree t = build_min (REINTERPRET_CAST_EXPR, type, expr); 4696 4697 if (!TREE_SIDE_EFFECTS (t) 4698 && type_dependent_expression_p (expr)) 4699 /* There might turn out to be side effects inside expr. */ 4700 TREE_SIDE_EFFECTS (t) = 1; 4701 return t; 4702 } 4703 4704 if (TREE_CODE (type) != REFERENCE_TYPE) 4705 { 4706 expr = decay_conversion (expr); 4707 4708 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 4709 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 4710 if (TREE_CODE (expr) == NOP_EXPR 4711 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 4712 expr = TREE_OPERAND (expr, 0); 4713 } 4714 4715 intype = TREE_TYPE (expr); 4716 4717 if (TREE_CODE (type) == REFERENCE_TYPE) 4718 { 4719 if (! real_lvalue_p (expr)) 4720 { 4721 error ("invalid reinterpret_cast of an rvalue expression of type `%T' to type `%T'", intype, type); 4722 return error_mark_node; 4723 } 4724 expr = build_unary_op (ADDR_EXPR, expr, 0); 4725 if (expr != error_mark_node) 4726 expr = build_reinterpret_cast 4727 (build_pointer_type (TREE_TYPE (type)), expr); 4728 if (expr != error_mark_node) 4729 expr = build_indirect_ref (expr, 0); 4730 return expr; 4731 } 4732 else if (same_type_ignoring_top_level_qualifiers_p (intype, type)) 4733 return build_static_cast (type, expr); 4734 4735 if (TYPE_PTR_P (type) && (TREE_CODE (intype) == INTEGER_TYPE 4736 || TREE_CODE (intype) == ENUMERAL_TYPE)) 4737 /* OK */; 4738 else if (TREE_CODE (type) == INTEGER_TYPE && TYPE_PTR_P (intype)) 4739 { 4740 if (TYPE_PRECISION (type) < TYPE_PRECISION (intype)) 4741 pedwarn ("reinterpret_cast from `%T' to `%T' loses precision", 4742 intype, type); 4743 } 4744 else if ((TYPE_PTRFN_P (type) && TYPE_PTRFN_P (intype)) 4745 || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))) 4746 { 4747 expr = decl_constant_value (expr); 4748 return fold (build1 (NOP_EXPR, type, expr)); 4749 } 4750 else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)) 4751 || (TYPE_PTROBV_P (type) && TYPE_PTROBV_P (intype))) 4752 { 4753 check_for_casting_away_constness (intype, type, "reinterpret_cast"); 4754 expr = decl_constant_value (expr); 4755 return fold (build1 (NOP_EXPR, type, expr)); 4756 } 4757 else if ((TYPE_PTRFN_P (type) && TYPE_PTROBV_P (intype)) 4758 || (TYPE_PTRFN_P (intype) && TYPE_PTROBV_P (type))) 4759 { 4760 pedwarn ("ISO C++ forbids casting between pointer-to-function and pointer-to-object"); 4761 expr = decl_constant_value (expr); 4762 return fold (build1 (NOP_EXPR, type, expr)); 4763 } 4764 else 4765 { 4766 error ("invalid reinterpret_cast from type `%T' to type `%T'", 4767 intype, type); 4768 return error_mark_node; 4769 } 4770 4771 return cp_convert (type, expr); 4772} 4773 4774tree 4775build_const_cast (tree type, tree expr) 4776{ 4777 tree intype; 4778 4779 if (type == error_mark_node || expr == error_mark_node) 4780 return error_mark_node; 4781 4782 if (processing_template_decl) 4783 { 4784 tree t = build_min (CONST_CAST_EXPR, type, expr); 4785 4786 if (!TREE_SIDE_EFFECTS (t) 4787 && type_dependent_expression_p (expr)) 4788 /* There might turn out to be side effects inside expr. */ 4789 TREE_SIDE_EFFECTS (t) = 1; 4790 return t; 4791 } 4792 4793 if (!POINTER_TYPE_P (type) && !TYPE_PTRMEM_P (type)) 4794 error ("invalid use of const_cast with type `%T', which is not a pointer, reference, nor a pointer-to-data-member type", type); 4795 else if (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE) 4796 { 4797 error ("invalid use of const_cast with type `%T', which is a pointer or reference to a function type", type); 4798 return error_mark_node; 4799 } 4800 4801 if (TREE_CODE (type) != REFERENCE_TYPE) 4802 { 4803 expr = decay_conversion (expr); 4804 4805 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 4806 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 4807 if (TREE_CODE (expr) == NOP_EXPR 4808 && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0))) 4809 expr = TREE_OPERAND (expr, 0); 4810 } 4811 4812 intype = TREE_TYPE (expr); 4813 4814 if (same_type_ignoring_top_level_qualifiers_p (intype, type)) 4815 return build_static_cast (type, expr); 4816 else if (TREE_CODE (type) == REFERENCE_TYPE) 4817 { 4818 if (! real_lvalue_p (expr)) 4819 { 4820 error ("invalid const_cast of an rvalue of type `%T' to type `%T'", intype, type); 4821 return error_mark_node; 4822 } 4823 4824 if (comp_ptr_ttypes_const (TREE_TYPE (type), intype)) 4825 { 4826 expr = build_unary_op (ADDR_EXPR, expr, 0); 4827 expr = build1 (NOP_EXPR, type, expr); 4828 return convert_from_reference (expr); 4829 } 4830 } 4831 else if (((TREE_CODE (type) == POINTER_TYPE 4832 && TREE_CODE (intype) == POINTER_TYPE) 4833 || (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))) 4834 && comp_ptr_ttypes_const (TREE_TYPE (type), TREE_TYPE (intype))) 4835 return cp_convert (type, expr); 4836 4837 error ("invalid const_cast from type `%T' to type `%T'", intype, type); 4838 return error_mark_node; 4839} 4840 4841/* Build an expression representing a cast to type TYPE of expression EXPR. 4842 4843 ALLOW_NONCONVERTING is true if we should allow non-converting constructors 4844 when doing the cast. */ 4845 4846tree 4847build_c_cast (tree type, tree expr) 4848{ 4849 tree value = expr; 4850 tree otype; 4851 4852 if (type == error_mark_node || expr == error_mark_node) 4853 return error_mark_node; 4854 4855 if (processing_template_decl) 4856 { 4857 tree t = build_min (CAST_EXPR, type, 4858 tree_cons (NULL_TREE, value, NULL_TREE)); 4859 /* We don't know if it will or will not have side effects. */ 4860 TREE_SIDE_EFFECTS (t) = 1; 4861 return t; 4862 } 4863 4864 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 4865 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */ 4866 if (TREE_CODE (type) != REFERENCE_TYPE 4867 && TREE_CODE (value) == NOP_EXPR 4868 && TREE_TYPE (value) == TREE_TYPE (TREE_OPERAND (value, 0))) 4869 value = TREE_OPERAND (value, 0); 4870 4871 if (TREE_CODE (type) == ARRAY_TYPE) 4872 { 4873 /* Allow casting from T1* to T2[] because Cfront allows it. 4874 NIHCL uses it. It is not valid ISO C++ however. */ 4875 if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) 4876 { 4877 pedwarn ("ISO C++ forbids casting to an array type `%T'", type); 4878 type = build_pointer_type (TREE_TYPE (type)); 4879 } 4880 else 4881 { 4882 error ("ISO C++ forbids casting to an array type `%T'", type); 4883 return error_mark_node; 4884 } 4885 } 4886 4887 if (TREE_CODE (type) == FUNCTION_TYPE 4888 || TREE_CODE (type) == METHOD_TYPE) 4889 { 4890 error ("invalid cast to function type `%T'", type); 4891 return error_mark_node; 4892 } 4893 4894 if (TREE_CODE (type) == VOID_TYPE) 4895 { 4896 /* Conversion to void does not cause any of the normal function to 4897 * pointer, array to pointer and lvalue to rvalue decays. */ 4898 4899 value = convert_to_void (value, /*implicit=*/NULL); 4900 return value; 4901 } 4902 4903 if (!complete_type_or_else (type, NULL_TREE)) 4904 return error_mark_node; 4905 4906 /* Convert functions and arrays to pointers and 4907 convert references to their expanded types, 4908 but don't convert any other types. If, however, we are 4909 casting to a class type, there's no reason to do this: the 4910 cast will only succeed if there is a converting constructor, 4911 and the default conversions will be done at that point. In 4912 fact, doing the default conversion here is actually harmful 4913 in cases like this: 4914 4915 typedef int A[2]; 4916 struct S { S(const A&); }; 4917 4918 since we don't want the array-to-pointer conversion done. */ 4919 if (!IS_AGGR_TYPE (type)) 4920 { 4921 if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE 4922 || (TREE_CODE (TREE_TYPE (value)) == METHOD_TYPE 4923 /* Don't do the default conversion on a ->* expression. */ 4924 && ! (TREE_CODE (type) == POINTER_TYPE 4925 && bound_pmf_p (value))) 4926 || TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE 4927 || TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE) 4928 value = decay_conversion (value); 4929 } 4930 else if (TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE) 4931 /* However, even for class types, we still need to strip away 4932 the reference type, since the call to convert_force below 4933 does not expect the input expression to be of reference 4934 type. */ 4935 value = convert_from_reference (value); 4936 4937 otype = TREE_TYPE (value); 4938 4939 /* Optionally warn about potentially worrisome casts. */ 4940 4941 if (warn_cast_qual 4942 && TREE_CODE (type) == POINTER_TYPE 4943 && TREE_CODE (otype) == POINTER_TYPE 4944 && !at_least_as_qualified_p (TREE_TYPE (type), 4945 TREE_TYPE (otype))) 4946 warning ("cast from `%T' to `%T' discards qualifiers from pointer target type", 4947 otype, type); 4948 4949 if (TREE_CODE (type) == INTEGER_TYPE 4950 && TYPE_PTR_P (otype) 4951 && TYPE_PRECISION (type) != TYPE_PRECISION (otype)) 4952 warning ("cast from pointer to integer of different size"); 4953 4954 if (TYPE_PTR_P (type) 4955 && TREE_CODE (otype) == INTEGER_TYPE 4956 && TYPE_PRECISION (type) != TYPE_PRECISION (otype) 4957 /* Don't warn about converting any constant. */ 4958 && !TREE_CONSTANT (value)) 4959 warning ("cast to pointer from integer of different size"); 4960 4961 if (TREE_CODE (type) == REFERENCE_TYPE) 4962 value = (convert_from_reference 4963 (convert_to_reference (type, value, CONV_C_CAST, 4964 LOOKUP_COMPLAIN, NULL_TREE))); 4965 else 4966 { 4967 tree ovalue; 4968 4969 value = decl_constant_value (value); 4970 4971 ovalue = value; 4972 value = convert_force (type, value, CONV_C_CAST); 4973 4974 /* Ignore any integer overflow caused by the cast. */ 4975 if (TREE_CODE (value) == INTEGER_CST) 4976 { 4977 TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue); 4978 TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue); 4979 } 4980 } 4981 4982 /* Warn about possible alignment problems. Do this here when we will have 4983 instantiated any necessary template types. */ 4984 if (STRICT_ALIGNMENT && warn_cast_align 4985 && TREE_CODE (type) == POINTER_TYPE 4986 && TREE_CODE (otype) == POINTER_TYPE 4987 && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE 4988 && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE 4989 && COMPLETE_TYPE_P (TREE_TYPE (otype)) 4990 && COMPLETE_TYPE_P (TREE_TYPE (type)) 4991 && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype))) 4992 warning ("cast from `%T' to `%T' increases required alignment of target type", 4993 otype, type); 4994 4995 /* Always produce some operator for an explicit cast, 4996 so we can tell (for -pedantic) that the cast is no lvalue. */ 4997 if (TREE_CODE (type) != REFERENCE_TYPE && value == expr 4998 && real_lvalue_p (value)) 4999 value = non_lvalue (value); 5000 5001 return value; 5002} 5003 5004/* Build an assignment expression of lvalue LHS from value RHS. 5005 MODIFYCODE is the code for a binary operator that we use 5006 to combine the old value of LHS with RHS to get the new value. 5007 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment. 5008 5009 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */ 5010 5011tree 5012build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs) 5013{ 5014 tree result; 5015 tree newrhs = rhs; 5016 tree lhstype = TREE_TYPE (lhs); 5017 tree olhstype = lhstype; 5018 tree olhs = NULL_TREE; 5019 5020 /* Avoid duplicate error messages from operands that had errors. */ 5021 if (lhs == error_mark_node || rhs == error_mark_node) 5022 return error_mark_node; 5023 5024 /* Handle control structure constructs used as "lvalues". */ 5025 switch (TREE_CODE (lhs)) 5026 { 5027 /* Handle --foo = 5; as these are valid constructs in C++. */ 5028 case PREDECREMENT_EXPR: 5029 case PREINCREMENT_EXPR: 5030 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0))) 5031 lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs), 5032 stabilize_reference (TREE_OPERAND (lhs, 0)), 5033 TREE_OPERAND (lhs, 1)); 5034 return build (COMPOUND_EXPR, lhstype, 5035 lhs, 5036 build_modify_expr (TREE_OPERAND (lhs, 0), 5037 modifycode, rhs)); 5038 5039 /* Handle (a, b) used as an "lvalue". */ 5040 case COMPOUND_EXPR: 5041 newrhs = build_modify_expr (TREE_OPERAND (lhs, 1), 5042 modifycode, rhs); 5043 if (newrhs == error_mark_node) 5044 return error_mark_node; 5045 return build (COMPOUND_EXPR, lhstype, 5046 TREE_OPERAND (lhs, 0), newrhs); 5047 5048 case MODIFY_EXPR: 5049 if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0))) 5050 lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs), 5051 stabilize_reference (TREE_OPERAND (lhs, 0)), 5052 TREE_OPERAND (lhs, 1)); 5053 newrhs = build_modify_expr (TREE_OPERAND (lhs, 0), modifycode, rhs); 5054 if (newrhs == error_mark_node) 5055 return error_mark_node; 5056 return build (COMPOUND_EXPR, lhstype, lhs, newrhs); 5057 5058 /* Handle (a ? b : c) used as an "lvalue". */ 5059 case COND_EXPR: 5060 { 5061 /* Produce (a ? (b = rhs) : (c = rhs)) 5062 except that the RHS goes through a save-expr 5063 so the code to compute it is only emitted once. */ 5064 tree cond; 5065 tree preeval = NULL_TREE; 5066 5067 rhs = stabilize_expr (rhs, &preeval); 5068 5069 /* Check this here to avoid odd errors when trying to convert 5070 a throw to the type of the COND_EXPR. */ 5071 if (!lvalue_or_else (lhs, "assignment")) 5072 return error_mark_node; 5073 5074 cond = build_conditional_expr 5075 (TREE_OPERAND (lhs, 0), 5076 build_modify_expr (cp_convert (TREE_TYPE (lhs), 5077 TREE_OPERAND (lhs, 1)), 5078 modifycode, rhs), 5079 build_modify_expr (cp_convert (TREE_TYPE (lhs), 5080 TREE_OPERAND (lhs, 2)), 5081 modifycode, rhs)); 5082 5083 if (cond == error_mark_node) 5084 return cond; 5085 /* Make sure the code to compute the rhs comes out 5086 before the split. */ 5087 if (preeval) 5088 cond = build (COMPOUND_EXPR, TREE_TYPE (lhs), preeval, cond); 5089 return cond; 5090 } 5091 5092 default: 5093 break; 5094 } 5095 5096 if (modifycode == INIT_EXPR) 5097 { 5098 if (TREE_CODE (rhs) == CONSTRUCTOR) 5099 { 5100 if (! same_type_p (TREE_TYPE (rhs), lhstype)) 5101 /* Call convert to generate an error; see PR 11063. */ 5102 rhs = convert (lhstype, rhs); 5103 result = build (INIT_EXPR, lhstype, lhs, rhs); 5104 TREE_SIDE_EFFECTS (result) = 1; 5105 return result; 5106 } 5107 else if (! IS_AGGR_TYPE (lhstype)) 5108 /* Do the default thing. */; 5109 else 5110 { 5111 result = build_special_member_call (lhs, complete_ctor_identifier, 5112 build_tree_list (NULL_TREE, rhs), 5113 TYPE_BINFO (lhstype), 5114 LOOKUP_NORMAL); 5115 if (result == NULL_TREE) 5116 return error_mark_node; 5117 return result; 5118 } 5119 } 5120 else 5121 { 5122 if (TREE_CODE (lhstype) == REFERENCE_TYPE) 5123 { 5124 lhs = convert_from_reference (lhs); 5125 olhstype = lhstype = TREE_TYPE (lhs); 5126 } 5127 lhs = require_complete_type (lhs); 5128 if (lhs == error_mark_node) 5129 return error_mark_node; 5130 5131 if (modifycode == NOP_EXPR) 5132 { 5133 /* `operator=' is not an inheritable operator. */ 5134 if (! IS_AGGR_TYPE (lhstype)) 5135 /* Do the default thing. */; 5136 else 5137 { 5138 result = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, 5139 lhs, rhs, make_node (NOP_EXPR), 5140 /*overloaded_p=*/NULL); 5141 if (result == NULL_TREE) 5142 return error_mark_node; 5143 return result; 5144 } 5145 lhstype = olhstype; 5146 } 5147 else 5148 { 5149 /* A binary op has been requested. Combine the old LHS 5150 value with the RHS producing the value we should actually 5151 store into the LHS. */ 5152 5153 my_friendly_assert (!PROMOTES_TO_AGGR_TYPE (lhstype, REFERENCE_TYPE), 5154 978652); 5155 lhs = stabilize_reference (lhs); 5156 newrhs = cp_build_binary_op (modifycode, lhs, rhs); 5157 if (newrhs == error_mark_node) 5158 { 5159 error (" in evaluation of `%Q(%#T, %#T)'", modifycode, 5160 TREE_TYPE (lhs), TREE_TYPE (rhs)); 5161 return error_mark_node; 5162 } 5163 5164 /* Now it looks like a plain assignment. */ 5165 modifycode = NOP_EXPR; 5166 } 5167 my_friendly_assert (TREE_CODE (lhstype) != REFERENCE_TYPE, 20011220); 5168 my_friendly_assert (TREE_CODE (TREE_TYPE (newrhs)) != REFERENCE_TYPE, 5169 20011220); 5170 } 5171 5172 /* Handle a cast used as an "lvalue". 5173 We have already performed any binary operator using the value as cast. 5174 Now convert the result to the cast type of the lhs, 5175 and then true type of the lhs and store it there; 5176 then convert result back to the cast type to be the value 5177 of the assignment. */ 5178 5179 switch (TREE_CODE (lhs)) 5180 { 5181 case NOP_EXPR: 5182 case CONVERT_EXPR: 5183 case FLOAT_EXPR: 5184 case FIX_TRUNC_EXPR: 5185 case FIX_FLOOR_EXPR: 5186 case FIX_ROUND_EXPR: 5187 case FIX_CEIL_EXPR: 5188 { 5189 tree inner_lhs = TREE_OPERAND (lhs, 0); 5190 tree result; 5191 5192 if (TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE 5193 || TREE_CODE (TREE_TYPE (newrhs)) == FUNCTION_TYPE 5194 || TREE_CODE (TREE_TYPE (newrhs)) == METHOD_TYPE 5195 || TREE_CODE (TREE_TYPE (newrhs)) == OFFSET_TYPE) 5196 newrhs = decay_conversion (newrhs); 5197 5198 /* ISO C++ 5.4/1: The result is an lvalue if T is a reference 5199 type, otherwise the result is an rvalue. */ 5200 if (! lvalue_p (lhs)) 5201 pedwarn ("ISO C++ forbids cast to non-reference type used as lvalue"); 5202 5203 result = build_modify_expr (inner_lhs, NOP_EXPR, 5204 cp_convert (TREE_TYPE (inner_lhs), 5205 cp_convert (lhstype, newrhs))); 5206 if (result == error_mark_node) 5207 return result; 5208 return cp_convert (TREE_TYPE (lhs), result); 5209 } 5210 5211 default: 5212 break; 5213 } 5214 5215 /* Now we have handled acceptable kinds of LHS that are not truly lvalues. 5216 Reject anything strange now. */ 5217 5218 if (!lvalue_or_else (lhs, "assignment")) 5219 return error_mark_node; 5220 5221 /* Warn about modifying something that is `const'. Don't warn if 5222 this is initialization. */ 5223 if (modifycode != INIT_EXPR 5224 && (TREE_READONLY (lhs) || CP_TYPE_CONST_P (lhstype) 5225 /* Functions are not modifiable, even though they are 5226 lvalues. */ 5227 || TREE_CODE (TREE_TYPE (lhs)) == FUNCTION_TYPE 5228 || TREE_CODE (TREE_TYPE (lhs)) == METHOD_TYPE 5229 /* If it's an aggregate and any field is const, then it is 5230 effectively const. */ 5231 || (CLASS_TYPE_P (lhstype) 5232 && C_TYPE_FIELDS_READONLY (lhstype)))) 5233 readonly_error (lhs, "assignment", 0); 5234 5235 /* If storing into a structure or union member, it has probably been 5236 given type `int'. Compute the type that would go with the actual 5237 amount of storage the member occupies. */ 5238 5239 if (TREE_CODE (lhs) == COMPONENT_REF 5240 && (TREE_CODE (lhstype) == INTEGER_TYPE 5241 || TREE_CODE (lhstype) == REAL_TYPE 5242 || TREE_CODE (lhstype) == ENUMERAL_TYPE)) 5243 { 5244 lhstype = TREE_TYPE (get_unwidened (lhs, 0)); 5245 5246 /* If storing in a field that is in actuality a short or narrower 5247 than one, we must store in the field in its actual type. */ 5248 5249 if (lhstype != TREE_TYPE (lhs)) 5250 { 5251 /* Avoid warnings converting integral types back into enums for 5252 enum bit fields. */ 5253 if (TREE_CODE (lhstype) == INTEGER_TYPE 5254 && TREE_CODE (olhstype) == ENUMERAL_TYPE) 5255 { 5256 if (TREE_SIDE_EFFECTS (lhs)) 5257 lhs = stabilize_reference (lhs); 5258 olhs = lhs; 5259 } 5260 lhs = copy_node (lhs); 5261 TREE_TYPE (lhs) = lhstype; 5262 } 5263 } 5264 5265 /* Convert new value to destination type. */ 5266 5267 if (TREE_CODE (lhstype) == ARRAY_TYPE) 5268 { 5269 int from_array; 5270 5271 if (!same_or_base_type_p (TYPE_MAIN_VARIANT (lhstype), 5272 TYPE_MAIN_VARIANT (TREE_TYPE (rhs)))) 5273 { 5274 error ("incompatible types in assignment of `%T' to `%T'", 5275 TREE_TYPE (rhs), lhstype); 5276 return error_mark_node; 5277 } 5278 5279 /* Allow array assignment in compiler-generated code. */ 5280 if (! DECL_ARTIFICIAL (current_function_decl)) 5281 pedwarn ("ISO C++ forbids assignment of arrays"); 5282 5283 from_array = TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE 5284 ? 1 + (modifycode != INIT_EXPR): 0; 5285 return build_vec_init (lhs, NULL_TREE, newrhs, from_array); 5286 } 5287 5288 if (modifycode == INIT_EXPR) 5289 newrhs = convert_for_initialization (lhs, lhstype, newrhs, LOOKUP_NORMAL, 5290 "initialization", NULL_TREE, 0); 5291 else 5292 { 5293 /* Avoid warnings on enum bit fields. */ 5294 if (TREE_CODE (olhstype) == ENUMERAL_TYPE 5295 && TREE_CODE (lhstype) == INTEGER_TYPE) 5296 { 5297 newrhs = convert_for_assignment (olhstype, newrhs, "assignment", 5298 NULL_TREE, 0); 5299 newrhs = convert_force (lhstype, newrhs, 0); 5300 } 5301 else 5302 newrhs = convert_for_assignment (lhstype, newrhs, "assignment", 5303 NULL_TREE, 0); 5304 if (TREE_CODE (newrhs) == CALL_EXPR 5305 && TYPE_NEEDS_CONSTRUCTING (lhstype)) 5306 newrhs = build_cplus_new (lhstype, newrhs); 5307 5308 /* Can't initialize directly from a TARGET_EXPR, since that would 5309 cause the lhs to be constructed twice, and possibly result in 5310 accidental self-initialization. So we force the TARGET_EXPR to be 5311 expanded without a target. */ 5312 if (TREE_CODE (newrhs) == TARGET_EXPR) 5313 newrhs = build (COMPOUND_EXPR, TREE_TYPE (newrhs), newrhs, 5314 TREE_OPERAND (newrhs, 0)); 5315 } 5316 5317 if (newrhs == error_mark_node) 5318 return error_mark_node; 5319 5320 result = build (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR, 5321 lhstype, lhs, newrhs); 5322 5323 TREE_SIDE_EFFECTS (result) = 1; 5324 5325 /* If we got the LHS in a different type for storing in, 5326 convert the result back to the nominal type of LHS 5327 so that the value we return always has the same type 5328 as the LHS argument. */ 5329 5330 if (olhstype == TREE_TYPE (result)) 5331 return result; 5332 if (olhs) 5333 { 5334 result = build (COMPOUND_EXPR, olhstype, result, olhs); 5335 TREE_NO_UNUSED_WARNING (result) = 1; 5336 return result; 5337 } 5338 return convert_for_assignment (olhstype, result, "assignment", 5339 NULL_TREE, 0); 5340} 5341 5342tree 5343build_x_modify_expr (tree lhs, enum tree_code modifycode, tree rhs) 5344{ 5345 if (processing_template_decl) 5346 return build_min_nt (MODOP_EXPR, lhs, 5347 build_min_nt (modifycode, NULL_TREE, NULL_TREE), rhs); 5348 5349 if (modifycode != NOP_EXPR) 5350 { 5351 tree rval = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, lhs, rhs, 5352 make_node (modifycode), 5353 /*overloaded_p=*/NULL); 5354 if (rval) 5355 return rval; 5356 } 5357 return build_modify_expr (lhs, modifycode, rhs); 5358} 5359 5360 5361/* Get difference in deltas for different pointer to member function 5362 types. Returns an integer constant of type PTRDIFF_TYPE_NODE. If 5363 the conversion is invalid, the constant is zero. If FORCE is true, 5364 then allow reverse conversions as well. 5365 5366 Note that the naming of FROM and TO is kind of backwards; the return 5367 value is what we add to a TO in order to get a FROM. They are named 5368 this way because we call this function to find out how to convert from 5369 a pointer to member of FROM to a pointer to member of TO. */ 5370 5371static tree 5372get_delta_difference (tree from, tree to, int force) 5373{ 5374 tree binfo; 5375 tree virt_binfo; 5376 base_kind kind; 5377 5378 binfo = lookup_base (to, from, ba_check, &kind); 5379 if (kind == bk_inaccessible || kind == bk_ambig) 5380 { 5381 error (" in pointer to member function conversion"); 5382 goto error; 5383 } 5384 if (!binfo) 5385 { 5386 if (!force) 5387 { 5388 error_not_base_type (from, to); 5389 error (" in pointer to member conversion"); 5390 goto error; 5391 } 5392 binfo = lookup_base (from, to, ba_check, &kind); 5393 if (!binfo) 5394 goto error; 5395 virt_binfo = binfo_from_vbase (binfo); 5396 if (virt_binfo) 5397 { 5398 /* This is a reinterpret cast, we choose to do nothing. */ 5399 warning ("pointer to member cast via virtual base `%T'", 5400 BINFO_TYPE (virt_binfo)); 5401 goto error; 5402 } 5403 return fold (convert_to_integer (ptrdiff_type_node, 5404 size_diffop (size_zero_node, 5405 BINFO_OFFSET (binfo)))); 5406 } 5407 5408 virt_binfo = binfo_from_vbase (binfo); 5409 if (!virt_binfo) 5410 return fold (convert_to_integer (ptrdiff_type_node, BINFO_OFFSET (binfo))); 5411 5412 /* This is a reinterpret cast, we choose to do nothing. */ 5413 if (force) 5414 warning ("pointer to member cast via virtual base `%T'", 5415 BINFO_TYPE (virt_binfo)); 5416 else 5417 error ("pointer to member conversion via virtual base `%T'", 5418 BINFO_TYPE (virt_binfo)); 5419 5420 error: 5421 return fold (convert_to_integer(ptrdiff_type_node, integer_zero_node)); 5422} 5423 5424/* Return a constructor for the pointer-to-member-function TYPE using 5425 the other components as specified. */ 5426 5427tree 5428build_ptrmemfunc1 (tree type, tree delta, tree pfn) 5429{ 5430 tree u = NULL_TREE; 5431 tree delta_field; 5432 tree pfn_field; 5433 5434 /* Pull the FIELD_DECLs out of the type. */ 5435 pfn_field = TYPE_FIELDS (type); 5436 delta_field = TREE_CHAIN (pfn_field); 5437 5438 /* Make sure DELTA has the type we want. */ 5439 delta = convert_and_check (delta_type_node, delta); 5440 5441 /* Finish creating the initializer. */ 5442 u = tree_cons (pfn_field, pfn, 5443 build_tree_list (delta_field, delta)); 5444 u = build_constructor (type, u); 5445 TREE_CONSTANT (u) = TREE_CONSTANT (pfn) && TREE_CONSTANT (delta); 5446 TREE_STATIC (u) = (TREE_CONSTANT (u) 5447 && (initializer_constant_valid_p (pfn, TREE_TYPE (pfn)) 5448 != NULL_TREE) 5449 && (initializer_constant_valid_p (delta, TREE_TYPE (delta)) 5450 != NULL_TREE)); 5451 return u; 5452} 5453 5454/* Build a constructor for a pointer to member function. It can be 5455 used to initialize global variables, local variable, or used 5456 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we 5457 want to be. 5458 5459 If FORCE is nonzero, then force this conversion, even if 5460 we would rather not do it. Usually set when using an explicit 5461 cast. 5462 5463 Return error_mark_node, if something goes wrong. */ 5464 5465tree 5466build_ptrmemfunc (tree type, tree pfn, int force) 5467{ 5468 tree fn; 5469 tree pfn_type; 5470 tree to_type; 5471 5472 if (error_operand_p (pfn)) 5473 return error_mark_node; 5474 5475 pfn_type = TREE_TYPE (pfn); 5476 to_type = build_ptrmemfunc_type (type); 5477 5478 /* Handle multiple conversions of pointer to member functions. */ 5479 if (TYPE_PTRMEMFUNC_P (pfn_type)) 5480 { 5481 tree delta = NULL_TREE; 5482 tree npfn = NULL_TREE; 5483 tree n; 5484 5485 if (!force 5486 && !can_convert_arg (to_type, TREE_TYPE (pfn), pfn)) 5487 error ("invalid conversion to type `%T' from type `%T'", 5488 to_type, pfn_type); 5489 5490 n = get_delta_difference (TYPE_PTRMEMFUNC_OBJECT_TYPE (pfn_type), 5491 TYPE_PTRMEMFUNC_OBJECT_TYPE (to_type), 5492 force); 5493 5494 /* We don't have to do any conversion to convert a 5495 pointer-to-member to its own type. But, we don't want to 5496 just return a PTRMEM_CST if there's an explicit cast; that 5497 cast should make the expression an invalid template argument. */ 5498 if (TREE_CODE (pfn) != PTRMEM_CST) 5499 { 5500 if (same_type_p (to_type, pfn_type)) 5501 return pfn; 5502 else if (integer_zerop (n)) 5503 return build_reinterpret_cast (to_type, pfn); 5504 } 5505 5506 if (TREE_SIDE_EFFECTS (pfn)) 5507 pfn = save_expr (pfn); 5508 5509 /* Obtain the function pointer and the current DELTA. */ 5510 if (TREE_CODE (pfn) == PTRMEM_CST) 5511 expand_ptrmemfunc_cst (pfn, &delta, &npfn); 5512 else 5513 { 5514 npfn = build_ptrmemfunc_access_expr (pfn, pfn_identifier); 5515 delta = build_ptrmemfunc_access_expr (pfn, delta_identifier); 5516 } 5517 5518 /* Just adjust the DELTA field. */ 5519 my_friendly_assert 5520 (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (delta), 5521 ptrdiff_type_node), 5522 20030727); 5523 if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_delta) 5524 n = cp_build_binary_op (LSHIFT_EXPR, n, integer_one_node); 5525 delta = cp_build_binary_op (PLUS_EXPR, delta, n); 5526 return build_ptrmemfunc1 (to_type, delta, npfn); 5527 } 5528 5529 /* Handle null pointer to member function conversions. */ 5530 if (integer_zerop (pfn)) 5531 { 5532 pfn = build_c_cast (type, integer_zero_node); 5533 return build_ptrmemfunc1 (to_type, 5534 integer_zero_node, 5535 pfn); 5536 } 5537 5538 if (type_unknown_p (pfn)) 5539 return instantiate_type (type, pfn, tf_error | tf_warning); 5540 5541 fn = TREE_OPERAND (pfn, 0); 5542 my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0); 5543 return make_ptrmem_cst (to_type, fn); 5544} 5545 5546/* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST 5547 given by CST. 5548 5549 ??? There is no consistency as to the types returned for the above 5550 values. Some code acts as if its a sizetype and some as if its 5551 integer_type_node. */ 5552 5553void 5554expand_ptrmemfunc_cst (tree cst, tree *delta, tree *pfn) 5555{ 5556 tree type = TREE_TYPE (cst); 5557 tree fn = PTRMEM_CST_MEMBER (cst); 5558 tree ptr_class, fn_class; 5559 5560 my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0); 5561 5562 /* The class that the function belongs to. */ 5563 fn_class = DECL_CONTEXT (fn); 5564 5565 /* The class that we're creating a pointer to member of. */ 5566 ptr_class = TYPE_PTRMEMFUNC_OBJECT_TYPE (type); 5567 5568 /* First, calculate the adjustment to the function's class. */ 5569 *delta = get_delta_difference (fn_class, ptr_class, /*force=*/0); 5570 5571 if (!DECL_VIRTUAL_P (fn)) 5572 *pfn = convert (TYPE_PTRMEMFUNC_FN_TYPE (type), build_addr_func (fn)); 5573 else 5574 { 5575 /* If we're dealing with a virtual function, we have to adjust 'this' 5576 again, to point to the base which provides the vtable entry for 5577 fn; the call will do the opposite adjustment. */ 5578 tree orig_class = DECL_CONTEXT (fn); 5579 tree binfo = binfo_or_else (orig_class, fn_class); 5580 *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta), 5581 *delta, BINFO_OFFSET (binfo))); 5582 5583 /* We set PFN to the vtable offset at which the function can be 5584 found, plus one (unless ptrmemfunc_vbit_in_delta, in which 5585 case delta is shifted left, and then incremented). */ 5586 *pfn = DECL_VINDEX (fn); 5587 *pfn = fold (build (MULT_EXPR, integer_type_node, *pfn, 5588 TYPE_SIZE_UNIT (vtable_entry_type))); 5589 5590 switch (TARGET_PTRMEMFUNC_VBIT_LOCATION) 5591 { 5592 case ptrmemfunc_vbit_in_pfn: 5593 *pfn = fold (build (PLUS_EXPR, integer_type_node, *pfn, 5594 integer_one_node)); 5595 break; 5596 5597 case ptrmemfunc_vbit_in_delta: 5598 *delta = fold (build (LSHIFT_EXPR, TREE_TYPE (*delta), 5599 *delta, integer_one_node)); 5600 *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta), 5601 *delta, integer_one_node)); 5602 break; 5603 5604 default: 5605 abort (); 5606 } 5607 5608 *pfn = fold (build1 (NOP_EXPR, TYPE_PTRMEMFUNC_FN_TYPE (type), 5609 *pfn)); 5610 } 5611} 5612 5613/* Return an expression for PFN from the pointer-to-member function 5614 given by T. */ 5615 5616tree 5617pfn_from_ptrmemfunc (tree t) 5618{ 5619 if (TREE_CODE (t) == PTRMEM_CST) 5620 { 5621 tree delta; 5622 tree pfn; 5623 5624 expand_ptrmemfunc_cst (t, &delta, &pfn); 5625 if (pfn) 5626 return pfn; 5627 } 5628 5629 return build_ptrmemfunc_access_expr (t, pfn_identifier); 5630} 5631 5632/* Expression EXPR is about to be implicitly converted to TYPE. Warn 5633 if this is a potentially dangerous thing to do. Returns a possibly 5634 marked EXPR. */ 5635 5636tree 5637dubious_conversion_warnings (tree type, tree expr, 5638 const char *errtype, tree fndecl, int parmnum) 5639{ 5640 type = non_reference (type); 5641 5642 /* Issue warnings about peculiar, but valid, uses of NULL. */ 5643 if (ARITHMETIC_TYPE_P (type) && expr == null_node) 5644 { 5645 if (fndecl) 5646 warning ("passing NULL used for non-pointer %s %P of `%D'", 5647 errtype, parmnum, fndecl); 5648 else 5649 warning ("%s to non-pointer type `%T' from NULL", errtype, type); 5650 } 5651 5652 /* Warn about assigning a floating-point type to an integer type. */ 5653 if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE 5654 && TREE_CODE (type) == INTEGER_TYPE) 5655 { 5656 if (fndecl) 5657 warning ("passing `%T' for %s %P of `%D'", 5658 TREE_TYPE (expr), errtype, parmnum, fndecl); 5659 else 5660 warning ("%s to `%T' from `%T'", errtype, type, TREE_TYPE (expr)); 5661 } 5662 /* And warn about assigning a negative value to an unsigned 5663 variable. */ 5664 else if (TREE_UNSIGNED (type) && TREE_CODE (type) != BOOLEAN_TYPE) 5665 { 5666 if (TREE_CODE (expr) == INTEGER_CST 5667 && TREE_NEGATED_INT (expr)) 5668 { 5669 if (fndecl) 5670 warning ("passing negative value `%E' for %s %P of `%D'", 5671 expr, errtype, parmnum, fndecl); 5672 else 5673 warning ("%s of negative value `%E' to `%T'", 5674 errtype, expr, type); 5675 } 5676 5677 overflow_warning (expr); 5678 5679 if (TREE_CONSTANT (expr)) 5680 expr = fold (expr); 5681 } 5682 return expr; 5683} 5684 5685/* Convert value RHS to type TYPE as preparation for an assignment to 5686 an lvalue of type TYPE. ERRTYPE is a string to use in error 5687 messages: "assignment", "return", etc. If FNDECL is non-NULL, we 5688 are doing the conversion in order to pass the PARMNUMth argument of 5689 FNDECL. */ 5690 5691static tree 5692convert_for_assignment (tree type, tree rhs, 5693 const char *errtype, tree fndecl, int parmnum) 5694{ 5695 tree rhstype; 5696 enum tree_code coder; 5697 5698 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */ 5699 if (TREE_CODE (rhs) == NON_LVALUE_EXPR) 5700 rhs = TREE_OPERAND (rhs, 0); 5701 5702 rhstype = TREE_TYPE (rhs); 5703 coder = TREE_CODE (rhstype); 5704 5705 if (TREE_CODE (type) == VECTOR_TYPE && coder == VECTOR_TYPE 5706 && ((*targetm.vector_opaque_p) (type) 5707 || (*targetm.vector_opaque_p) (rhstype))) 5708 return convert (type, rhs); 5709 5710 if (rhs == error_mark_node || rhstype == error_mark_node) 5711 return error_mark_node; 5712 if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node) 5713 return error_mark_node; 5714 5715 /* The RHS of an assignment cannot have void type. */ 5716 if (coder == VOID_TYPE) 5717 { 5718 error ("void value not ignored as it ought to be"); 5719 return error_mark_node; 5720 } 5721 5722 /* Simplify the RHS if possible. */ 5723 if (TREE_CODE (rhs) == CONST_DECL) 5724 rhs = DECL_INITIAL (rhs); 5725 5726 /* We do not use decl_constant_value here because of this case: 5727 5728 const char* const s = "s"; 5729 5730 The conversion rules for a string literal are more lax than for a 5731 variable; in particular, a string literal can be converted to a 5732 "char *" but the variable "s" cannot be converted in the same 5733 way. If the conversion is allowed, the optimization should be 5734 performed while creating the converted expression. */ 5735 5736 /* [expr.ass] 5737 5738 The expression is implicitly converted (clause _conv_) to the 5739 cv-unqualified type of the left operand. 5740 5741 We allow bad conversions here because by the time we get to this point 5742 we are committed to doing the conversion. If we end up doing a bad 5743 conversion, convert_like will complain. */ 5744 if (!can_convert_arg_bad (type, rhstype, rhs)) 5745 { 5746 /* When -Wno-pmf-conversions is use, we just silently allow 5747 conversions from pointers-to-members to plain pointers. If 5748 the conversion doesn't work, cp_convert will complain. */ 5749 if (!warn_pmf2ptr 5750 && TYPE_PTR_P (type) 5751 && TYPE_PTRMEMFUNC_P (rhstype)) 5752 rhs = cp_convert (strip_top_quals (type), rhs); 5753 else 5754 { 5755 /* If the right-hand side has unknown type, then it is an 5756 overloaded function. Call instantiate_type to get error 5757 messages. */ 5758 if (rhstype == unknown_type_node) 5759 instantiate_type (type, rhs, tf_error | tf_warning); 5760 else if (fndecl) 5761 error ("cannot convert `%T' to `%T' for argument `%P' to `%D'", 5762 rhstype, type, parmnum, fndecl); 5763 else 5764 error ("cannot convert `%T' to `%T' in %s", rhstype, type, 5765 errtype); 5766 return error_mark_node; 5767 } 5768 } 5769 return perform_implicit_conversion (strip_top_quals (type), rhs); 5770} 5771 5772/* Convert RHS to be of type TYPE. 5773 If EXP is nonzero, it is the target of the initialization. 5774 ERRTYPE is a string to use in error messages. 5775 5776 Two major differences between the behavior of 5777 `convert_for_assignment' and `convert_for_initialization' 5778 are that references are bashed in the former, while 5779 copied in the latter, and aggregates are assigned in 5780 the former (operator=) while initialized in the 5781 latter (X(X&)). 5782 5783 If using constructor make sure no conversion operator exists, if one does 5784 exist, an ambiguity exists. 5785 5786 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */ 5787 5788tree 5789convert_for_initialization (tree exp, tree type, tree rhs, int flags, 5790 const char *errtype, tree fndecl, int parmnum) 5791{ 5792 enum tree_code codel = TREE_CODE (type); 5793 tree rhstype; 5794 enum tree_code coder; 5795 5796 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue. 5797 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */ 5798 if (TREE_CODE (rhs) == NOP_EXPR 5799 && TREE_TYPE (rhs) == TREE_TYPE (TREE_OPERAND (rhs, 0)) 5800 && codel != REFERENCE_TYPE) 5801 rhs = TREE_OPERAND (rhs, 0); 5802 5803 if (rhs == error_mark_node 5804 || (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)) 5805 return error_mark_node; 5806 5807 if (TREE_CODE (TREE_TYPE (rhs)) == REFERENCE_TYPE) 5808 rhs = convert_from_reference (rhs); 5809 5810 if ((TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE 5811 && TREE_CODE (type) != ARRAY_TYPE 5812 && (TREE_CODE (type) != REFERENCE_TYPE 5813 || TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE)) 5814 || (TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE 5815 && (TREE_CODE (type) != REFERENCE_TYPE 5816 || TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE)) 5817 || TREE_CODE (TREE_TYPE (rhs)) == METHOD_TYPE) 5818 rhs = decay_conversion (rhs); 5819 5820 rhstype = TREE_TYPE (rhs); 5821 coder = TREE_CODE (rhstype); 5822 5823 if (coder == ERROR_MARK) 5824 return error_mark_node; 5825 5826 /* We accept references to incomplete types, so we can 5827 return here before checking if RHS is of complete type. */ 5828 5829 if (codel == REFERENCE_TYPE) 5830 { 5831 /* This should eventually happen in convert_arguments. */ 5832 int savew = 0, savee = 0; 5833 5834 if (fndecl) 5835 savew = warningcount, savee = errorcount; 5836 rhs = initialize_reference (type, rhs, /*decl=*/NULL_TREE, 5837 /*cleanup=*/NULL); 5838 if (fndecl) 5839 { 5840 if (warningcount > savew) 5841 cp_warning_at ("in passing argument %P of `%+D'", parmnum, fndecl); 5842 else if (errorcount > savee) 5843 cp_error_at ("in passing argument %P of `%+D'", parmnum, fndecl); 5844 } 5845 return rhs; 5846 } 5847 5848 if (exp != 0) 5849 exp = require_complete_type (exp); 5850 if (exp == error_mark_node) 5851 return error_mark_node; 5852 5853 rhstype = non_reference (rhstype); 5854 5855 type = complete_type (type); 5856 5857 if (IS_AGGR_TYPE (type)) 5858 return ocp_convert (type, rhs, CONV_IMPLICIT|CONV_FORCE_TEMP, flags); 5859 5860 return convert_for_assignment (type, rhs, errtype, fndecl, parmnum); 5861} 5862 5863/* Expand an ASM statement with operands, handling output operands 5864 that are not variables or INDIRECT_REFS by transforming such 5865 cases into cases that expand_asm_operands can handle. 5866 5867 Arguments are same as for expand_asm_operands. 5868 5869 We don't do default conversions on all inputs, because it can screw 5870 up operands that are expected to be in memory. */ 5871 5872void 5873c_expand_asm_operands (tree string, tree outputs, tree inputs, tree clobbers, 5874 int vol, location_t locus) 5875{ 5876 int noutputs = list_length (outputs); 5877 int i; 5878 /* o[I] is the place that output number I should be written. */ 5879 tree *o = alloca (noutputs * sizeof (tree)); 5880 tree tail; 5881 5882 /* Record the contents of OUTPUTS before it is modified. */ 5883 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) 5884 o[i] = TREE_VALUE (tail); 5885 5886 /* Generate the ASM_OPERANDS insn; 5887 store into the TREE_VALUEs of OUTPUTS some trees for 5888 where the values were actually stored. */ 5889 expand_asm_operands (string, outputs, inputs, clobbers, vol, locus); 5890 5891 /* Copy all the intermediate outputs into the specified outputs. */ 5892 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++) 5893 { 5894 if (o[i] != TREE_VALUE (tail)) 5895 { 5896 expand_expr (build_modify_expr (o[i], NOP_EXPR, TREE_VALUE (tail)), 5897 const0_rtx, VOIDmode, EXPAND_NORMAL); 5898 free_temp_slots (); 5899 5900 /* Restore the original value so that it's correct the next 5901 time we expand this function. */ 5902 TREE_VALUE (tail) = o[i]; 5903 } 5904 /* Detect modification of read-only values. 5905 (Otherwise done by build_modify_expr.) */ 5906 else 5907 { 5908 tree type = TREE_TYPE (o[i]); 5909 if (type != error_mark_node 5910 && (CP_TYPE_CONST_P (type) 5911 || (CLASS_TYPE_P (type) && C_TYPE_FIELDS_READONLY (type)))) 5912 readonly_error (o[i], "modification by `asm'", 1); 5913 } 5914 } 5915 5916 /* Those MODIFY_EXPRs could do autoincrements. */ 5917 emit_queue (); 5918} 5919 5920/* If RETVAL is the address of, or a reference to, a local variable or 5921 temporary give an appropriate warning. */ 5922 5923static void 5924maybe_warn_about_returning_address_of_local (tree retval) 5925{ 5926 tree valtype = TREE_TYPE (DECL_RESULT (current_function_decl)); 5927 tree whats_returned = retval; 5928 5929 for (;;) 5930 { 5931 if (TREE_CODE (whats_returned) == COMPOUND_EXPR) 5932 whats_returned = TREE_OPERAND (whats_returned, 1); 5933 else if (TREE_CODE (whats_returned) == CONVERT_EXPR 5934 || TREE_CODE (whats_returned) == NON_LVALUE_EXPR 5935 || TREE_CODE (whats_returned) == NOP_EXPR) 5936 whats_returned = TREE_OPERAND (whats_returned, 0); 5937 else 5938 break; 5939 } 5940 5941 if (TREE_CODE (whats_returned) != ADDR_EXPR) 5942 return; 5943 whats_returned = TREE_OPERAND (whats_returned, 0); 5944 5945 if (TREE_CODE (valtype) == REFERENCE_TYPE) 5946 { 5947 if (TREE_CODE (whats_returned) == AGGR_INIT_EXPR 5948 || TREE_CODE (whats_returned) == TARGET_EXPR) 5949 { 5950 warning ("returning reference to temporary"); 5951 return; 5952 } 5953 if (TREE_CODE (whats_returned) == VAR_DECL 5954 && DECL_NAME (whats_returned) 5955 && TEMP_NAME_P (DECL_NAME (whats_returned))) 5956 { 5957 warning ("reference to non-lvalue returned"); 5958 return; 5959 } 5960 } 5961 5962 if (TREE_CODE (whats_returned) == VAR_DECL 5963 && DECL_NAME (whats_returned) 5964 && DECL_FUNCTION_SCOPE_P (whats_returned) 5965 && !(TREE_STATIC (whats_returned) 5966 || TREE_PUBLIC (whats_returned))) 5967 { 5968 if (TREE_CODE (valtype) == REFERENCE_TYPE) 5969 cp_warning_at ("reference to local variable `%D' returned", 5970 whats_returned); 5971 else 5972 cp_warning_at ("address of local variable `%D' returned", 5973 whats_returned); 5974 return; 5975 } 5976} 5977 5978/* Check that returning RETVAL from the current function is valid. 5979 Return an expression explicitly showing all conversions required to 5980 change RETVAL into the function return type, and to assign it to 5981 the DECL_RESULT for the function. */ 5982 5983tree 5984check_return_expr (tree retval) 5985{ 5986 tree result; 5987 /* The type actually returned by the function, after any 5988 promotions. */ 5989 tree valtype; 5990 int fn_returns_value_p; 5991 5992 /* A `volatile' function is one that isn't supposed to return, ever. 5993 (This is a G++ extension, used to get better code for functions 5994 that call the `volatile' function.) */ 5995 if (TREE_THIS_VOLATILE (current_function_decl)) 5996 warning ("function declared `noreturn' has a `return' statement"); 5997 5998 /* Check for various simple errors. */ 5999 if (DECL_DESTRUCTOR_P (current_function_decl)) 6000 { 6001 if (retval) 6002 error ("returning a value from a destructor"); 6003 return NULL_TREE; 6004 } 6005 else if (DECL_CONSTRUCTOR_P (current_function_decl)) 6006 { 6007 if (in_function_try_handler) 6008 /* If a return statement appears in a handler of the 6009 function-try-block of a constructor, the program is ill-formed. */ 6010 error ("cannot return from a handler of a function-try-block of a constructor"); 6011 else if (retval) 6012 /* You can't return a value from a constructor. */ 6013 error ("returning a value from a constructor"); 6014 return NULL_TREE; 6015 } 6016 6017 if (processing_template_decl) 6018 { 6019 current_function_returns_value = 1; 6020 return retval; 6021 } 6022 6023 /* When no explicit return-value is given in a function with a named 6024 return value, the named return value is used. */ 6025 result = DECL_RESULT (current_function_decl); 6026 valtype = TREE_TYPE (result); 6027 my_friendly_assert (valtype != NULL_TREE, 19990924); 6028 fn_returns_value_p = !VOID_TYPE_P (valtype); 6029 if (!retval && DECL_NAME (result) && fn_returns_value_p) 6030 retval = result; 6031 6032 /* Check for a return statement with no return value in a function 6033 that's supposed to return a value. */ 6034 if (!retval && fn_returns_value_p) 6035 { 6036 pedwarn ("return-statement with no value, in function returning '%T'", 6037 valtype); 6038 /* Clear this, so finish_function won't say that we reach the 6039 end of a non-void function (which we don't, we gave a 6040 return!). */ 6041 current_function_returns_null = 0; 6042 } 6043 /* Check for a return statement with a value in a function that 6044 isn't supposed to return a value. */ 6045 else if (retval && !fn_returns_value_p) 6046 { 6047 if (VOID_TYPE_P (TREE_TYPE (retval))) 6048 /* You can return a `void' value from a function of `void' 6049 type. In that case, we have to evaluate the expression for 6050 its side-effects. */ 6051 finish_expr_stmt (retval); 6052 else 6053 pedwarn ("return-statement with a value, in function " 6054 "returning 'void'"); 6055 6056 current_function_returns_null = 1; 6057 6058 /* There's really no value to return, after all. */ 6059 return NULL_TREE; 6060 } 6061 else if (!retval) 6062 /* Remember that this function can sometimes return without a 6063 value. */ 6064 current_function_returns_null = 1; 6065 else 6066 /* Remember that this function did return a value. */ 6067 current_function_returns_value = 1; 6068 6069 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */ 6070 if ((DECL_OVERLOADED_OPERATOR_P (current_function_decl) == NEW_EXPR 6071 || DECL_OVERLOADED_OPERATOR_P (current_function_decl) == VEC_NEW_EXPR) 6072 && !TYPE_NOTHROW_P (TREE_TYPE (current_function_decl)) 6073 && ! flag_check_new 6074 && null_ptr_cst_p (retval)) 6075 warning ("`operator new' must not return NULL unless it is declared `throw()' (or -fcheck-new is in effect)"); 6076 6077 /* Effective C++ rule 15. See also start_function. */ 6078 if (warn_ecpp 6079 && DECL_NAME (current_function_decl) == ansi_assopname(NOP_EXPR) 6080 && retval != current_class_ref) 6081 warning ("`operator=' should return a reference to `*this'"); 6082 6083 /* The fabled Named Return Value optimization, as per [class.copy]/15: 6084 6085 [...] For a function with a class return type, if the expression 6086 in the return statement is the name of a local object, and the cv- 6087 unqualified type of the local object is the same as the function 6088 return type, an implementation is permitted to omit creating the tem- 6089 porary object to hold the function return value [...] 6090 6091 So, if this is a value-returning function that always returns the same 6092 local variable, remember it. 6093 6094 It might be nice to be more flexible, and choose the first suitable 6095 variable even if the function sometimes returns something else, but 6096 then we run the risk of clobbering the variable we chose if the other 6097 returned expression uses the chosen variable somehow. And people expect 6098 this restriction, anyway. (jason 2000-11-19) 6099 6100 See finish_function, cxx_expand_function_start, and 6101 cp_copy_res_decl_for_inlining for other pieces of this 6102 optimization. */ 6103 6104 if (fn_returns_value_p && flag_elide_constructors) 6105 { 6106 if (retval != NULL_TREE 6107 && (current_function_return_value == NULL_TREE 6108 || current_function_return_value == retval) 6109 && TREE_CODE (retval) == VAR_DECL 6110 && DECL_CONTEXT (retval) == current_function_decl 6111 && ! TREE_STATIC (retval) 6112 && (DECL_ALIGN (retval) 6113 >= DECL_ALIGN (DECL_RESULT (current_function_decl))) 6114 && same_type_p ((TYPE_MAIN_VARIANT 6115 (TREE_TYPE (retval))), 6116 (TYPE_MAIN_VARIANT 6117 (TREE_TYPE (TREE_TYPE (current_function_decl)))))) 6118 current_function_return_value = retval; 6119 else 6120 current_function_return_value = error_mark_node; 6121 } 6122 6123 /* We don't need to do any conversions when there's nothing being 6124 returned. */ 6125 if (!retval || retval == error_mark_node) 6126 return retval; 6127 6128 /* Do any required conversions. */ 6129 if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl)) 6130 /* No conversions are required. */ 6131 ; 6132 else 6133 { 6134 /* The type the function is declared to return. */ 6135 tree functype = TREE_TYPE (TREE_TYPE (current_function_decl)); 6136 6137 /* First convert the value to the function's return type, then 6138 to the type of return value's location to handle the 6139 case that functype is smaller than the valtype. */ 6140 retval = convert_for_initialization 6141 (NULL_TREE, functype, retval, LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING, 6142 "return", NULL_TREE, 0); 6143 retval = convert (valtype, retval); 6144 6145 /* If the conversion failed, treat this just like `return;'. */ 6146 if (retval == error_mark_node) 6147 return retval; 6148 /* We can't initialize a register from a AGGR_INIT_EXPR. */ 6149 else if (! current_function_returns_struct 6150 && TREE_CODE (retval) == TARGET_EXPR 6151 && TREE_CODE (TREE_OPERAND (retval, 1)) == AGGR_INIT_EXPR) 6152 retval = build (COMPOUND_EXPR, TREE_TYPE (retval), retval, 6153 TREE_OPERAND (retval, 0)); 6154 else 6155 maybe_warn_about_returning_address_of_local (retval); 6156 } 6157 6158 /* Actually copy the value returned into the appropriate location. */ 6159 if (retval && retval != result) 6160 retval = build (INIT_EXPR, TREE_TYPE (result), result, retval); 6161 6162 return retval; 6163} 6164 6165 6166/* Returns nonzero if the pointer-type FROM can be converted to the 6167 pointer-type TO via a qualification conversion. If CONSTP is -1, 6168 then we return nonzero if the pointers are similar, and the 6169 cv-qualification signature of FROM is a proper subset of that of TO. 6170 6171 If CONSTP is positive, then all outer pointers have been 6172 const-qualified. */ 6173 6174static int 6175comp_ptr_ttypes_real (tree to, tree from, int constp) 6176{ 6177 bool to_more_cv_qualified = false; 6178 6179 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 6180 { 6181 if (TREE_CODE (to) != TREE_CODE (from)) 6182 return 0; 6183 6184 if (TREE_CODE (from) == OFFSET_TYPE 6185 && !same_type_p (TYPE_OFFSET_BASETYPE (from), 6186 TYPE_OFFSET_BASETYPE (to))) 6187 return 0; 6188 6189 /* Const and volatile mean something different for function types, 6190 so the usual checks are not appropriate. */ 6191 if (TREE_CODE (to) != FUNCTION_TYPE && TREE_CODE (to) != METHOD_TYPE) 6192 { 6193 if (!at_least_as_qualified_p (to, from)) 6194 return 0; 6195 6196 if (!at_least_as_qualified_p (from, to)) 6197 { 6198 if (constp == 0) 6199 return 0; 6200 to_more_cv_qualified = true; 6201 } 6202 6203 if (constp > 0) 6204 constp &= TYPE_READONLY (to); 6205 } 6206 6207 if (TREE_CODE (to) != POINTER_TYPE && !TYPE_PTRMEM_P (to)) 6208 return ((constp >= 0 || to_more_cv_qualified) 6209 && same_type_ignoring_top_level_qualifiers_p (to, from)); 6210 } 6211} 6212 6213/* When comparing, say, char ** to char const **, this function takes 6214 the 'char *' and 'char const *'. Do not pass non-pointer/reference 6215 types to this function. */ 6216 6217int 6218comp_ptr_ttypes (tree to, tree from) 6219{ 6220 return comp_ptr_ttypes_real (to, from, 1); 6221} 6222 6223/* Returns 1 if to and from are (possibly multi-level) pointers to the same 6224 type or inheritance-related types, regardless of cv-quals. */ 6225 6226int 6227ptr_reasonably_similar (tree to, tree from) 6228{ 6229 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 6230 { 6231 /* Any target type is similar enough to void. */ 6232 if (TREE_CODE (to) == VOID_TYPE 6233 || TREE_CODE (from) == VOID_TYPE) 6234 return 1; 6235 6236 if (TREE_CODE (to) != TREE_CODE (from)) 6237 return 0; 6238 6239 if (TREE_CODE (from) == OFFSET_TYPE 6240 && comptypes (TYPE_OFFSET_BASETYPE (to), 6241 TYPE_OFFSET_BASETYPE (from), 6242 COMPARE_BASE | COMPARE_DERIVED)) 6243 continue; 6244 6245 if (TREE_CODE (to) == INTEGER_TYPE 6246 && TYPE_PRECISION (to) == TYPE_PRECISION (from)) 6247 return 1; 6248 6249 if (TREE_CODE (to) == FUNCTION_TYPE) 6250 return 1; 6251 6252 if (TREE_CODE (to) != POINTER_TYPE) 6253 return comptypes 6254 (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from), 6255 COMPARE_BASE | COMPARE_DERIVED); 6256 } 6257} 6258 6259/* Like comp_ptr_ttypes, for const_cast. */ 6260 6261static int 6262comp_ptr_ttypes_const (tree to, tree from) 6263{ 6264 for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from)) 6265 { 6266 if (TREE_CODE (to) != TREE_CODE (from)) 6267 return 0; 6268 6269 if (TREE_CODE (from) == OFFSET_TYPE 6270 && same_type_p (TYPE_OFFSET_BASETYPE (from), 6271 TYPE_OFFSET_BASETYPE (to))) 6272 continue; 6273 6274 if (TREE_CODE (to) != POINTER_TYPE) 6275 return same_type_ignoring_top_level_qualifiers_p (to, from); 6276 } 6277} 6278 6279/* Returns the type qualifiers for this type, including the qualifiers on the 6280 elements for an array type. */ 6281 6282int 6283cp_type_quals (tree type) 6284{ 6285 type = strip_array_types (type); 6286 if (type == error_mark_node) 6287 return TYPE_UNQUALIFIED; 6288 return TYPE_QUALS (type); 6289} 6290 6291/* Returns nonzero if the TYPE contains a mutable member. */ 6292 6293bool 6294cp_has_mutable_p (tree type) 6295{ 6296 type = strip_array_types (type); 6297 6298 return CLASS_TYPE_P (type) && CLASSTYPE_HAS_MUTABLE (type); 6299} 6300 6301/* Subroutine of casts_away_constness. Make T1 and T2 point at 6302 exemplar types such that casting T1 to T2 is casting away castness 6303 if and only if there is no implicit conversion from T1 to T2. */ 6304 6305static void 6306casts_away_constness_r (tree *t1, tree *t2) 6307{ 6308 int quals1; 6309 int quals2; 6310 6311 /* [expr.const.cast] 6312 6313 For multi-level pointer to members and multi-level mixed pointers 6314 and pointers to members (conv.qual), the "member" aspect of a 6315 pointer to member level is ignored when determining if a const 6316 cv-qualifier has been cast away. */ 6317 if (TYPE_PTRMEM_P (*t1)) 6318 *t1 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t1)); 6319 if (TYPE_PTRMEM_P (*t2)) 6320 *t2 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t2)); 6321 6322 /* [expr.const.cast] 6323 6324 For two pointer types: 6325 6326 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type 6327 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type 6328 K is min(N,M) 6329 6330 casting from X1 to X2 casts away constness if, for a non-pointer 6331 type T there does not exist an implicit conversion (clause 6332 _conv_) from: 6333 6334 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N * 6335 6336 to 6337 6338 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */ 6339 6340 if (TREE_CODE (*t1) != POINTER_TYPE 6341 || TREE_CODE (*t2) != POINTER_TYPE) 6342 { 6343 *t1 = cp_build_qualified_type (void_type_node, 6344 cp_type_quals (*t1)); 6345 *t2 = cp_build_qualified_type (void_type_node, 6346 cp_type_quals (*t2)); 6347 return; 6348 } 6349 6350 quals1 = cp_type_quals (*t1); 6351 quals2 = cp_type_quals (*t2); 6352 *t1 = TREE_TYPE (*t1); 6353 *t2 = TREE_TYPE (*t2); 6354 casts_away_constness_r (t1, t2); 6355 *t1 = build_pointer_type (*t1); 6356 *t2 = build_pointer_type (*t2); 6357 *t1 = cp_build_qualified_type (*t1, quals1); 6358 *t2 = cp_build_qualified_type (*t2, quals2); 6359} 6360 6361/* Returns nonzero if casting from TYPE1 to TYPE2 casts away 6362 constness. */ 6363 6364static bool 6365casts_away_constness (tree t1, tree t2) 6366{ 6367 if (TREE_CODE (t2) == REFERENCE_TYPE) 6368 { 6369 /* [expr.const.cast] 6370 6371 Casting from an lvalue of type T1 to an lvalue of type T2 6372 using a reference cast casts away constness if a cast from an 6373 rvalue of type "pointer to T1" to the type "pointer to T2" 6374 casts away constness. */ 6375 t1 = (TREE_CODE (t1) == REFERENCE_TYPE ? TREE_TYPE (t1) : t1); 6376 return casts_away_constness (build_pointer_type (t1), 6377 build_pointer_type (TREE_TYPE (t2))); 6378 } 6379 6380 if (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2)) 6381 /* [expr.const.cast] 6382 6383 Casting from an rvalue of type "pointer to data member of X 6384 of type T1" to the type "pointer to data member of Y of type 6385 T2" casts away constness if a cast from an rvalue of type 6386 "pointer to T1" to the type "pointer to T2" casts away 6387 constness. */ 6388 return casts_away_constness 6389 (build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t1)), 6390 build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t2))); 6391 6392 /* Casting away constness is only something that makes sense for 6393 pointer or reference types. */ 6394 if (TREE_CODE (t1) != POINTER_TYPE 6395 || TREE_CODE (t2) != POINTER_TYPE) 6396 return false; 6397 6398 /* Top-level qualifiers don't matter. */ 6399 t1 = TYPE_MAIN_VARIANT (t1); 6400 t2 = TYPE_MAIN_VARIANT (t2); 6401 casts_away_constness_r (&t1, &t2); 6402 if (!can_convert (t2, t1)) 6403 return true; 6404 6405 return false; 6406} 6407 6408/* If T is a REFERENCE_TYPE return the type to which T refers. 6409 Otherwise, return T itself. */ 6410 6411tree 6412non_reference (tree t) 6413{ 6414 if (TREE_CODE (t) == REFERENCE_TYPE) 6415 t = TREE_TYPE (t); 6416 return t; 6417} 6418