gcc/cp/typeck.c

   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 Free Software Foundation, Inc.
   4    Hacked by Michael Tiemann (tiemann@cygnus.com)
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 59 Temple Place - Suite 330,
  21 Boston, 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
  49 static tree convert_for_assignment (tree, tree, const char *, tree, int);
  50 static tree cp_pointer_int_sum (enum tree_code, tree, tree);
  51 static tree rationalize_conditional_expr (enum tree_code, tree);
  52 static int comp_ptr_ttypes_real (tree, tree, int);
  53 static int comp_ptr_ttypes_const (tree, tree);
  54 static bool comp_except_types (tree, tree, bool);
  55 static bool comp_array_types (tree, tree, bool);
  56 static tree common_base_type (tree, tree);
  57 static tree lookup_anon_field (tree, tree);
  58 static tree pointer_diff (tree, tree, tree);
  59 static tree get_delta_difference (tree, tree, int);
  60 static void casts_away_constness_r (tree *, tree *);
  61 static bool casts_away_constness (tree, tree);
  62 static void maybe_warn_about_returning_address_of_local (tree);
  63 static tree lookup_destructor (tree, tree, tree);
  64
  65 /* Return the target type of TYPE, which means return T for:
  66    T*, T&, T[], T (...), and otherwise, just T.  */
  67
  68 tree
  69 target_type (tree type)
  70 {
  71   type = non_reference (type);
  72   while (TREE_CODE (type) == POINTER_TYPE
  73          || TREE_CODE (type) == ARRAY_TYPE
  74          || TREE_CODE (type) == FUNCTION_TYPE
  75          || TREE_CODE (type) == METHOD_TYPE
  76          || TYPE_PTRMEM_P (type))
  77     type = TREE_TYPE (type);
  78   return type;
  79 }
  80
  81 /* Do `exp = require_complete_type (exp);' to make sure exp
  82    does not have an incomplete type.  (That includes void types.)
  83    Returns the error_mark_node if the VALUE does not have
  84    complete type when this function returns.  */
  85
  86 tree
  87 require_complete_type (tree value)
  88 {
  89   tree type;
  90
  91   if (processing_template_decl || value == error_mark_node)
  92     return value;
  93
  94   if (TREE_CODE (value) == OVERLOAD)
  95     type = unknown_type_node;
  96   else
  97     type = TREE_TYPE (value);
  98
  99   /* First, detect a valid value with a complete type.  */
 100   if (COMPLETE_TYPE_P (type))
 101     return value;
 102
 103   if (complete_type_or_else (type, value))
 104     return value;
 105   else
 106     return error_mark_node;
 107 }
 108
 109 /* Try to complete TYPE, if it is incomplete.  For example, if TYPE is
 110    a template instantiation, do the instantiation.  Returns TYPE,
 111    whether or not it could be completed, unless something goes
 112    horribly wrong, in which case the error_mark_node is returned.  */
 113
 114 tree
 115 complete_type (tree type)
 116 {
 117   if (type == NULL_TREE)
 118     /* Rather than crash, we return something sure to cause an error
 119        at some point.  */
 120     return error_mark_node;
 121
 122   if (type == error_mark_node || COMPLETE_TYPE_P (type))
 123     ;
 124   else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
 125     {
 126       tree t = complete_type (TREE_TYPE (type));
 127       if (COMPLETE_TYPE_P (t) && ! processing_template_decl)
 128         layout_type (type);
 129       TYPE_NEEDS_CONSTRUCTING (type)
 130         = TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (t));
 131       TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type)
 132         = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TYPE_MAIN_VARIANT (t));
 133     }
 134   else if (CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INSTANTIATION (type))
 135     instantiate_class_template (TYPE_MAIN_VARIANT (type));
 136
 137   return type;
 138 }
 139
 140 /* Like complete_type, but issue an error if the TYPE cannot be completed.
 141    VALUE is used for informative diagnostics.  DIAG_TYPE indicates the type
 142    of diagnostic: 0 for an error, 1 for a warning, 2 for a pedwarn.
 143    Returns NULL_TREE if the type cannot be made complete.  */
 144
 145 tree
 146 complete_type_or_diagnostic (tree type, tree value, int diag_type)
 147 {
 148   type = complete_type (type);
 149   if (type == error_mark_node)
 150     /* We already issued an error.  */
 151     return NULL_TREE;
 152   else if (!COMPLETE_TYPE_P (type))
 153     {
 154       cxx_incomplete_type_diagnostic (value, type, diag_type);
 155       return NULL_TREE;
 156     }
 157   else
 158     return type;
 159 }
 160
 161 /* Return truthvalue of whether type of EXP is instantiated.  */
 162
 163 int
 164 type_unknown_p (tree exp)
 165 {
 166   return (TREE_CODE (exp) == OVERLOAD
 167           || TREE_CODE (exp) == TREE_LIST
 168           || TREE_TYPE (exp) == unknown_type_node);
 169 }
 170
 171 \f
 172 /* Return the common type of two parameter lists.
 173    We assume that comptypes has already been done and returned 1;
 174    if that isn't so, this may crash.
 175
 176    As an optimization, free the space we allocate if the parameter
 177    lists are already common.  */
 178
 179 tree
 180 commonparms (tree p1, tree p2)
 181 {
 182   tree oldargs = p1, newargs, n;
 183   int i, len;
 184   int any_change = 0;
 185
 186   len = list_length (p1);
 187   newargs = tree_last (p1);
 188
 189   if (newargs == void_list_node)
 190     i = 1;
 191   else
 192     {
 193       i = 0;
 194       newargs = 0;
 195     }
 196
 197   for (; i < len; i++)
 198     newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
 199
 200   n = newargs;
 201
 202   for (i = 0; p1;
 203        p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n), i++)
 204     {
 205       if (TREE_PURPOSE (p1) && !TREE_PURPOSE (p2))
 206         {
 207           TREE_PURPOSE (n) = TREE_PURPOSE (p1);
 208           any_change = 1;
 209         }
 210       else if (! TREE_PURPOSE (p1))
 211         {
 212           if (TREE_PURPOSE (p2))
 213             {
 214               TREE_PURPOSE (n) = TREE_PURPOSE (p2);
 215               any_change = 1;
 216             }
 217         }
 218       else
 219         {
 220           if (1 != simple_cst_equal (TREE_PURPOSE (p1), TREE_PURPOSE (p2)))
 221             any_change = 1;
 222           TREE_PURPOSE (n) = TREE_PURPOSE (p2);
 223         }
 224       if (TREE_VALUE (p1) != TREE_VALUE (p2))
 225         {
 226           any_change = 1;
 227           TREE_VALUE (n) = merge_types (TREE_VALUE (p1), TREE_VALUE (p2));
 228         }
 229       else
 230         TREE_VALUE (n) = TREE_VALUE (p1);
 231     }
 232   if (! any_change)
 233     return oldargs;
 234
 235   return newargs;
 236 }
 237
 238 /* Given a type, perhaps copied for a typedef,
 239    find the "original" version of it.  */
 240 tree
 241 original_type (tree t)
 242 {
 243   while (TYPE_NAME (t) != NULL_TREE)
 244     {
 245       tree x = TYPE_NAME (t);
 246       if (TREE_CODE (x) != TYPE_DECL)
 247         break;
 248       x = DECL_ORIGINAL_TYPE (x);
 249       if (x == NULL_TREE)
 250         break;
 251       t = x;
 252     }
 253   return t;
 254 }
 255
 256 /* T1 and T2 are arithmetic or enumeration types.  Return the type
 257    that will result from the "usual arithmetic conversions" on T1 and
 258    T2 as described in [expr].  */
 259
 260 tree
 261 type_after_usual_arithmetic_conversions (tree t1, tree t2)
 262 {
 263   enum tree_code code1 = TREE_CODE (t1);
 264   enum tree_code code2 = TREE_CODE (t2);
 265   tree attributes;
 266
 267   /* FIXME: Attributes.  */
 268   my_friendly_assert (ARITHMETIC_TYPE_P (t1)
 269                       || TREE_CODE (t1) == COMPLEX_TYPE
 270                       || TREE_CODE (t1) == ENUMERAL_TYPE,
 271                       19990725);
 272   my_friendly_assert (ARITHMETIC_TYPE_P (t2)
 273                       || TREE_CODE (t2) == COMPLEX_TYPE
 274                       || TREE_CODE (t2) == ENUMERAL_TYPE,
 275                       19990725);
 276
 277   /* In what follows, we slightly generalize the rules given in [expr] so
 278      as to deal with `long long' and `complex'.  First, merge the
 279      attributes.  */
 280   attributes = (*targetm.merge_type_attributes) (t1, t2);
 281
 282   /* If one type is complex, form the common type of the non-complex
 283      components, then make that complex.  Use T1 or T2 if it is the
 284      required type.  */
 285   if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
 286     {
 287       tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
 288       tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
 289       tree subtype
 290         = type_after_usual_arithmetic_conversions (subtype1, subtype2);
 291
 292       if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
 293         return build_type_attribute_variant (t1, attributes);
 294       else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
 295         return build_type_attribute_variant (t2, attributes);
 296       else
 297         return build_type_attribute_variant (build_complex_type (subtype),
 298                                              attributes);
 299     }
 300
 301   /* If only one is real, use it as the result.  */
 302   if (code1 == REAL_TYPE && code2 != REAL_TYPE)
 303     return build_type_attribute_variant (t1, attributes);
 304   if (code2 == REAL_TYPE && code1 != REAL_TYPE)
 305     return build_type_attribute_variant (t2, attributes);
 306
 307   /* Perform the integral promotions.  */
 308   if (code1 != REAL_TYPE)
 309     {
 310       t1 = type_promotes_to (t1);
 311       t2 = type_promotes_to (t2);
 312     }
 313
 314   /* Both real or both integers; use the one with greater precision.  */
 315   if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
 316     return build_type_attribute_variant (t1, attributes);
 317   else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
 318     return build_type_attribute_variant (t2, attributes);
 319
 320   /* The types are the same; no need to do anything fancy.  */
 321   if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 322     return build_type_attribute_variant (t1, attributes);
 323
 324   if (code1 != REAL_TYPE)
 325     {
 326       /* If one is a sizetype, use it so size_binop doesn't blow up.  */
 327       if (TYPE_IS_SIZETYPE (t1) > TYPE_IS_SIZETYPE (t2))
 328         return build_type_attribute_variant (t1, attributes);
 329       if (TYPE_IS_SIZETYPE (t2) > TYPE_IS_SIZETYPE (t1))
 330         return build_type_attribute_variant (t2, attributes);
 331
 332       /* If one is unsigned long long, then convert the other to unsigned
 333          long long.  */
 334       if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_unsigned_type_node)
 335           || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_unsigned_type_node))
 336         return build_type_attribute_variant (long_long_unsigned_type_node,
 337                                              attributes);
 338       /* If one is a long long, and the other is an unsigned long, and
 339          long long can represent all the values of an unsigned long, then
 340          convert to a long long.  Otherwise, convert to an unsigned long
 341          long.  Otherwise, if either operand is long long, convert the
 342          other to long long.
 343
 344          Since we're here, we know the TYPE_PRECISION is the same;
 345          therefore converting to long long cannot represent all the values
 346          of an unsigned long, so we choose unsigned long long in that
 347          case.  */
 348       if (same_type_p (TYPE_MAIN_VARIANT (t1), long_long_integer_type_node)
 349           || same_type_p (TYPE_MAIN_VARIANT (t2), long_long_integer_type_node))
 350         {
 351           tree t = ((TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2))
 352                     ? long_long_unsigned_type_node
 353                     : long_long_integer_type_node);
 354           return build_type_attribute_variant (t, attributes);
 355         }
 356
 357       /* Go through the same procedure, but for longs.  */
 358       if (same_type_p (TYPE_MAIN_VARIANT (t1), long_unsigned_type_node)
 359           || same_type_p (TYPE_MAIN_VARIANT (t2), long_unsigned_type_node))
 360         return build_type_attribute_variant (long_unsigned_type_node,
 361                                              attributes);
 362       if (same_type_p (TYPE_MAIN_VARIANT (t1), long_integer_type_node)
 363           || same_type_p (TYPE_MAIN_VARIANT (t2), long_integer_type_node))
 364         {
 365           tree t = ((TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2))
 366                     ? long_unsigned_type_node : long_integer_type_node);
 367           return build_type_attribute_variant (t, attributes);
 368         }
 369       /* Otherwise prefer the unsigned one.  */
 370       if (TREE_UNSIGNED (t1))
 371         return build_type_attribute_variant (t1, attributes);
 372       else
 373         return build_type_attribute_variant (t2, attributes);
 374     }
 375   else
 376     {
 377       if (same_type_p (TYPE_MAIN_VARIANT (t1), long_double_type_node)
 378           || same_type_p (TYPE_MAIN_VARIANT (t2), long_double_type_node))
 379         return build_type_attribute_variant (long_double_type_node,
 380                                              attributes);
 381       if (same_type_p (TYPE_MAIN_VARIANT (t1), double_type_node)
 382           || same_type_p (TYPE_MAIN_VARIANT (t2), double_type_node))
 383         return build_type_attribute_variant (double_type_node,
 384                                              attributes);
 385       if (same_type_p (TYPE_MAIN_VARIANT (t1), float_type_node)
 386           || same_type_p (TYPE_MAIN_VARIANT (t2), float_type_node))
 387         return build_type_attribute_variant (float_type_node,
 388                                              attributes);
 389
 390       /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of
 391          the standard C++ floating-point types.  Logic earlier in this
 392          function has already eliminated the possibility that
 393          TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no
 394          compelling reason to choose one or the other.  */
 395       return build_type_attribute_variant (t1, attributes);
 396     }
 397 }
 398
 399 /* Subroutine of composite_pointer_type to implement the recursive
 400    case.  See that function for documentation fo the parameters.  */
 401
 402 static tree
 403 composite_pointer_type_r (tree t1, tree t2, const char* location)
 404 {
 405   tree pointee1;
 406   tree pointee2;
 407   tree result_type;
 408   tree attributes;
 409
 410   /* Determine the types pointed to by T1 and T2.  */
 411   if (TREE_CODE (t1) == POINTER_TYPE)
 412     {
 413       pointee1 = TREE_TYPE (t1);
 414       pointee2 = TREE_TYPE (t2);
 415     }
 416   else
 417     {
 418       pointee1 = TYPE_PTRMEM_POINTED_TO_TYPE (t1);
 419       pointee2 = TYPE_PTRMEM_POINTED_TO_TYPE (t2);
 420     }
 421
 422   /* [expr.rel]
 423
 424      Otherwise, the composite pointer type is a pointer type
 425      similar (_conv.qual_) to the type of one of the operands,
 426      with a cv-qualification signature (_conv.qual_) that is the
 427      union of the cv-qualification signatures of the operand
 428      types.  */
 429   if (same_type_ignoring_top_level_qualifiers_p (pointee1, pointee2))
 430     result_type = pointee1;
 431   else if ((TREE_CODE (pointee1) == POINTER_TYPE
 432             && TREE_CODE (pointee2) == POINTER_TYPE)
 433            || (TYPE_PTR_TO_MEMBER_P (pointee1)
 434                && TYPE_PTR_TO_MEMBER_P (pointee2)))
 435     result_type = composite_pointer_type_r (pointee1, pointee2, location);
 436   else
 437     {
 438       pedwarn ("%s between distinct pointer types `%T' and `%T' "
 439                "lacks a cast",
 440                location, t1, t2);
 441       result_type = void_type_node;
 442     }
 443   result_type = cp_build_qualified_type (result_type,
 444                                          (cp_type_quals (pointee1)
 445                                           | cp_type_quals (pointee2)));
 446   result_type = build_pointer_type (result_type);
 447   /* If the original types were pointers to members, so is the
 448      result.  */
 449   if (TYPE_PTR_TO_MEMBER_P (t1))
 450     {
 451       if (!same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1),
 452                         TYPE_PTRMEM_CLASS_TYPE (t2)))
 453         pedwarn ("%s between distinct pointer types `%T' and `%T' "
 454                  "lacks a cast",
 455                  location, t1, t2);
 456       result_type = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1),
 457                                        result_type);
 458     }
 459
 460   /* Merge the attributes.  */
 461   attributes = (*targetm.merge_type_attributes) (t1, t2);
 462   return build_type_attribute_variant (result_type, attributes);
 463 }
 464
 465 /* Return the composite pointer type (see [expr.rel]) for T1 and T2.
 466    ARG1 and ARG2 are the values with those types.  The LOCATION is a
 467    string describing the current location, in case an error occurs.
 468
 469    This routine also implements the computation of a common type for
 470    pointers-to-members as per [expr.eq].  */
 471
 472 tree
 473 composite_pointer_type (tree t1, tree t2, tree arg1, tree arg2,
 474                         const char* location)
 475 {
 476   tree class1;
 477   tree class2;
 478
 479   /* [expr.rel]
 480
 481      If one operand is a null pointer constant, the composite pointer
 482      type is the type of the other operand.  */
 483   if (null_ptr_cst_p (arg1))
 484     return t2;
 485   if (null_ptr_cst_p (arg2))
 486     return t1;
 487
 488   /* We have:
 489
 490        [expr.rel]
 491
 492        If one of the operands has type "pointer to cv1 void*", then
 493        the other has type "pointer to cv2T", and the composite pointer
 494        type is "pointer to cv12 void", where cv12 is the union of cv1
 495        and cv2.
 496
 497     If either type is a pointer to void, make sure it is T1.  */
 498   if (TREE_CODE (t2) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t2)))
 499     {
 500       tree t;
 501       t = t1;
 502       t1 = t2;
 503       t2 = t;
 504     }
 505
 506   /* Now, if T1 is a pointer to void, merge the qualifiers.  */
 507   if (TREE_CODE (t1) == POINTER_TYPE && VOID_TYPE_P (TREE_TYPE (t1)))
 508     {
 509       tree attributes;
 510       tree result_type;
 511
 512       if (pedantic && TYPE_PTRFN_P (t2))
 513         pedwarn ("ISO C++ forbids %s between pointer of type `void *' and pointer-to-function", location);
 514       result_type
 515         = cp_build_qualified_type (void_type_node,
 516                                    (cp_type_quals (TREE_TYPE (t1))
 517                                     | cp_type_quals (TREE_TYPE (t2))));
 518       result_type = build_pointer_type (result_type);
 519       /* Merge the attributes.  */
 520       attributes = (*targetm.merge_type_attributes) (t1, t2);
 521       return build_type_attribute_variant (result_type, attributes);
 522     }
 523
 524   /* [expr.eq] permits the application of a pointer conversion to
 525      bring the pointers to a common type.  */
 526   if (TREE_CODE (t1) == POINTER_TYPE && TREE_CODE (t2) == POINTER_TYPE
 527       && CLASS_TYPE_P (TREE_TYPE (t1))
 528       && CLASS_TYPE_P (TREE_TYPE (t2))
 529       && !same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (t1),
 530                                                      TREE_TYPE (t2)))
 531     {
 532       class1 = TREE_TYPE (t1);
 533       class2 = TREE_TYPE (t2);
 534
 535       if (DERIVED_FROM_P (class1, class2))
 536         t2 = (build_pointer_type
 537               (cp_build_qualified_type (class1, TYPE_QUALS (class2))));
 538       else if (DERIVED_FROM_P (class2, class1))
 539         t1 = (build_pointer_type
 540               (cp_build_qualified_type (class2, TYPE_QUALS (class1))));
 541       else
 542         {
 543           error ("%s between distinct pointer types `%T' and `%T' "
 544                  "lacks a cast", location, t1, t2);
 545           return error_mark_node;
 546         }
 547     }
 548   /* [expr.eq] permits the application of a pointer-to-member
 549      conversion to change the class type of one of the types.  */
 550   else if (TYPE_PTR_TO_MEMBER_P (t1)
 551            && !same_type_p (TYPE_PTRMEM_CLASS_TYPE (t1),
 552                             TYPE_PTRMEM_CLASS_TYPE (t2)))
 553     {
 554       class1 = TYPE_PTRMEM_CLASS_TYPE (t1);
 555       class2 = TYPE_PTRMEM_CLASS_TYPE (t2);
 556
 557       if (DERIVED_FROM_P (class1, class2))
 558         t1 = build_ptrmem_type (class2, TYPE_PTRMEM_POINTED_TO_TYPE (t1));
 559       else if (DERIVED_FROM_P (class2, class1))
 560         t2 = build_ptrmem_type (class1, TYPE_PTRMEM_POINTED_TO_TYPE (t2));
 561       else
 562         {
 563           error ("%s between distinct pointer-to-member types `%T' and `%T' "
 564                  "lacks a cast", location, t1, t2);
 565           return error_mark_node;
 566         }
 567     }
 568
 569   return composite_pointer_type_r (t1, t2, location);
 570 }
 571
 572 /* Return the merged type of two types.
 573    We assume that comptypes has already been done and returned 1;
 574    if that isn't so, this may crash.
 575
 576    This just combines attributes and default arguments; any other
 577    differences would cause the two types to compare unalike.  */
 578
 579 tree
 580 merge_types (tree t1, tree t2)
 581 {
 582   register enum tree_code code1;
 583   register enum tree_code code2;
 584   tree attributes;
 585
 586   /* Save time if the two types are the same.  */
 587   if (t1 == t2)
 588     return t1;
 589   if (original_type (t1) == original_type (t2))
 590     return t1;
 591
 592   /* If one type is nonsense, use the other.  */
 593   if (t1 == error_mark_node)
 594     return t2;
 595   if (t2 == error_mark_node)
 596     return t1;
 597
 598   /* Merge the attributes.  */
 599   attributes = (*targetm.merge_type_attributes) (t1, t2);
 600
 601   if (TYPE_PTRMEMFUNC_P (t1))
 602     t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1);
 603   if (TYPE_PTRMEMFUNC_P (t2))
 604     t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2);
 605
 606   code1 = TREE_CODE (t1);
 607   code2 = TREE_CODE (t2);
 608
 609   switch (code1)
 610     {
 611     case POINTER_TYPE:
 612     case REFERENCE_TYPE:
 613       /* For two pointers, do this recursively on the target type.  */
 614       {
 615         tree target = merge_types (TREE_TYPE (t1), TREE_TYPE (t2));
 616         int quals = cp_type_quals (t1);
 617
 618         if (code1 == POINTER_TYPE)
 619           t1 = build_pointer_type (target);
 620         else
 621           t1 = build_reference_type (target);
 622         t1 = build_type_attribute_variant (t1, attributes);
 623         t1 = cp_build_qualified_type (t1, quals);
 624
 625         if (TREE_CODE (target) == METHOD_TYPE)
 626           t1 = build_ptrmemfunc_type (t1);
 627
 628         return t1;
 629       }
 630
 631     case OFFSET_TYPE:
 632       {
 633         int quals;
 634         tree pointee;
 635         quals = cp_type_quals (t1);
 636         pointee = merge_types (TYPE_PTRMEM_POINTED_TO_TYPE (t1),
 637                                TYPE_PTRMEM_POINTED_TO_TYPE (t2));
 638         t1 = build_ptrmem_type (TYPE_PTRMEM_CLASS_TYPE (t1),
 639                                 pointee);
 640         t1 = cp_build_qualified_type (t1, quals);
 641         break;
 642       }
 643
 644     case ARRAY_TYPE:
 645       {
 646         tree elt = merge_types (TREE_TYPE (t1), TREE_TYPE (t2));
 647         /* Save space: see if the result is identical to one of the args.  */
 648         if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
 649           return build_type_attribute_variant (t1, attributes);
 650         if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
 651           return build_type_attribute_variant (t2, attributes);
 652         /* Merge the element types, and have a size if either arg has one.  */
 653         t1 = build_cplus_array_type
 654           (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
 655         break;
 656       }
 657
 658     case FUNCTION_TYPE:
 659       /* Function types: prefer the one that specified arg types.
 660          If both do, merge the arg types.  Also merge the return types.  */
 661       {
 662         tree valtype = merge_types (TREE_TYPE (t1), TREE_TYPE (t2));
 663         tree p1 = TYPE_ARG_TYPES (t1);
 664         tree p2 = TYPE_ARG_TYPES (t2);
 665         tree rval, raises;
 666
 667         /* Save space: see if the result is identical to one of the args.  */
 668         if (valtype == TREE_TYPE (t1) && ! p2)
 669           return build_type_attribute_variant (t1, attributes);
 670         if (valtype == TREE_TYPE (t2) && ! p1)
 671           return build_type_attribute_variant (t2, attributes);
 672
 673         /* Simple way if one arg fails to specify argument types.  */
 674         if (p1 == NULL_TREE || TREE_VALUE (p1) == void_type_node)
 675           {
 676             rval = build_function_type (valtype, p2);
 677             if ((raises = TYPE_RAISES_EXCEPTIONS (t2)))
 678               rval = build_exception_variant (rval, raises);
 679             return build_type_attribute_variant (rval, attributes);
 680           }
 681         raises = TYPE_RAISES_EXCEPTIONS (t1);
 682         if (p2 == NULL_TREE || TREE_VALUE (p2) == void_type_node)
 683           {
 684             rval = build_function_type (valtype, p1);
 685             if (raises)
 686               rval = build_exception_variant (rval, raises);
 687             return build_type_attribute_variant (rval, attributes);
 688           }
 689
 690         rval = build_function_type (valtype, commonparms (p1, p2));
 691         t1 = build_exception_variant (rval, raises);
 692         break;
 693       }
 694
 695     case METHOD_TYPE:
 696       {
 697         /* Get this value the long way, since TYPE_METHOD_BASETYPE
 698            is just the main variant of this.  */
 699         tree basetype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t2)));
 700         tree raises = TYPE_RAISES_EXCEPTIONS (t1);
 701         tree t3;
 702
 703         /* If this was a member function type, get back to the
 704            original type of type member function (i.e., without
 705            the class instance variable up front.  */
 706         t1 = build_function_type (TREE_TYPE (t1),
 707                                   TREE_CHAIN (TYPE_ARG_TYPES (t1)));
 708         t2 = build_function_type (TREE_TYPE (t2),
 709                                   TREE_CHAIN (TYPE_ARG_TYPES (t2)));
 710         t3 = merge_types (t1, t2);
 711         t3 = build_method_type_directly (basetype, TREE_TYPE (t3),
 712                                          TYPE_ARG_TYPES (t3));
 713         t1 = build_exception_variant (t3, raises);
 714         break;
 715       }
 716
 717     default:;
 718     }
 719   return build_type_attribute_variant (t1, attributes);
 720 }
 721
 722 /* Return the common type of two types.
 723    We assume that comptypes has already been done and returned 1;
 724    if that isn't so, this may crash.
 725
 726    This is the type for the result of most arithmetic operations
 727    if the operands have the given two types.  */
 728
 729 tree
 730 common_type (tree t1, tree t2)
 731 {
 732   enum tree_code code1;
 733   enum tree_code code2;
 734
 735   /* If one type is nonsense, bail.  */
 736   if (t1 == error_mark_node || t2 == error_mark_node)
 737     return error_mark_node;
 738
 739   code1 = TREE_CODE (t1);
 740   code2 = TREE_CODE (t2);
 741
 742   if ((ARITHMETIC_TYPE_P (t1) || code1 == ENUMERAL_TYPE
 743        || code1 == COMPLEX_TYPE)
 744       && (ARITHMETIC_TYPE_P (t2) || code2 == ENUMERAL_TYPE
 745           || code2 == COMPLEX_TYPE))
 746     return type_after_usual_arithmetic_conversions (t1, t2);
 747
 748   else if ((TYPE_PTR_P (t1) && TYPE_PTR_P (t2))
 749            || (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2))
 750            || (TYPE_PTRMEMFUNC_P (t1) && TYPE_PTRMEMFUNC_P (t2)))
 751     return composite_pointer_type (t1, t2, error_mark_node, error_mark_node,
 752                                    "conversion");
 753   else
 754     abort ();
 755 }
 756 \f
 757 /* Compare two exception specifier types for exactness or subsetness, if
 758    allowed. Returns false for mismatch, true for match (same, or
 759    derived and !exact).
 760
 761    [except.spec] "If a class X ... objects of class X or any class publicly
 762    and unambiguously derived from X. Similarly, if a pointer type Y * ...
 763    exceptions of type Y * or that are pointers to any type publicly and
 764    unambiguously derived from Y. Otherwise a function only allows exceptions
 765    that have the same type ..."
 766    This does not mention cv qualifiers and is different to what throw
 767    [except.throw] and catch [except.catch] will do. They will ignore the
 768    top level cv qualifiers, and allow qualifiers in the pointer to class
 769    example.
 770
 771    We implement the letter of the standard.  */
 772
 773 static bool
 774 comp_except_types (tree a, tree b, bool exact)
 775 {
 776   if (same_type_p (a, b))
 777     return true;
 778   else if (!exact)
 779     {
 780       if (cp_type_quals (a) || cp_type_quals (b))
 781         return false;
 782
 783       if (TREE_CODE (a) == POINTER_TYPE
 784           && TREE_CODE (b) == POINTER_TYPE)
 785         {
 786           a = TREE_TYPE (a);
 787           b = TREE_TYPE (b);
 788           if (cp_type_quals (a) || cp_type_quals (b))
 789             return false;
 790         }
 791
 792       if (TREE_CODE (a) != RECORD_TYPE
 793           || TREE_CODE (b) != RECORD_TYPE)
 794         return false;
 795
 796       if (ACCESSIBLY_UNIQUELY_DERIVED_P (a, b))
 797         return true;
 798     }
 799   return false;
 800 }
 801
 802 /* Return true if TYPE1 and TYPE2 are equivalent exception specifiers.
 803    If EXACT is false, T2 can be stricter than T1 (according to 15.4/7),
 804    otherwise it must be exact. Exception lists are unordered, but
 805    we've already filtered out duplicates. Most lists will be in order,
 806    we should try to make use of that.  */
 807
 808 bool
 809 comp_except_specs (tree t1, tree t2, bool exact)
 810 {
 811   tree probe;
 812   tree base;
 813   int  length = 0;
 814
 815   if (t1 == t2)
 816     return true;
 817
 818   if (t1 == NULL_TREE)              /* T1 is ...  */
 819     return t2 == NULL_TREE || !exact;
 820   if (!TREE_VALUE (t1)) /* t1 is EMPTY */
 821     return t2 != NULL_TREE && !TREE_VALUE (t2);
 822   if (t2 == NULL_TREE)              /* T2 is ...  */
 823     return false;
 824   if (TREE_VALUE (t1) && !TREE_VALUE (t2)) /* T2 is EMPTY, T1 is not */
 825     return !exact;
 826
 827   /* Neither set is ... or EMPTY, make sure each part of T2 is in T1.
 828      Count how many we find, to determine exactness. For exact matching and
 829      ordered T1, T2, this is an O(n) operation, otherwise its worst case is
 830      O(nm).  */
 831   for (base = t1; t2 != NULL_TREE; t2 = TREE_CHAIN (t2))
 832     {
 833       for (probe = base; probe != NULL_TREE; probe = TREE_CHAIN (probe))
 834         {
 835           tree a = TREE_VALUE (probe);
 836           tree b = TREE_VALUE (t2);
 837
 838           if (comp_except_types (a, b, exact))
 839             {
 840               if (probe == base && exact)
 841                 base = TREE_CHAIN (probe);
 842               length++;
 843               break;
 844             }
 845         }
 846       if (probe == NULL_TREE)
 847         return false;
 848     }
 849   return !exact || base == NULL_TREE || length == list_length (t1);
 850 }
 851
 852 /* Compare the array types T1 and T2.  ALLOW_REDECLARATION is true if
 853    [] can match [size].  */
 854
 855 static bool
 856 comp_array_types (tree t1, tree t2, bool allow_redeclaration)
 857 {
 858   tree d1;
 859   tree d2;
 860
 861   if (t1 == t2)
 862     return true;
 863
 864   /* The type of the array elements must be the same.  */
 865   if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
 866     return false;
 867
 868   d1 = TYPE_DOMAIN (t1);
 869   d2 = TYPE_DOMAIN (t2);
 870
 871   if (d1 == d2)
 872     return true;
 873
 874   /* If one of the arrays is dimensionless, and the other has a
 875      dimension, they are of different types.  However, it is valid to
 876      write:
 877
 878        extern int a[];
 879        int a[3];
 880
 881      by [basic.link]:
 882
 883        declarations for an array object can specify
 884        array types that differ by the presence or absence of a major
 885        array bound (_dcl.array_).  */
 886   if (!d1 || !d2)
 887     return allow_redeclaration;
 888
 889   /* Check that the dimensions are the same.  */
 890   return (cp_tree_equal (TYPE_MIN_VALUE (d1), TYPE_MIN_VALUE (d2))
 891           && cp_tree_equal (TYPE_MAX_VALUE (d1), TYPE_MAX_VALUE (d2)));
 892 }
 893
 894 /* Return true if T1 and T2 are related as allowed by STRICT.  STRICT
 895    is a bitwise-or of the COMPARE_* flags.  */
 896
 897 bool
 898 comptypes (tree t1, tree t2, int strict)
 899 {
 900   if (t1 == t2)
 901     return true;
 902
 903   /* This should never happen.  */
 904   my_friendly_assert (t1 != error_mark_node, 307);
 905
 906   /* Suppress errors caused by previously reported errors */
 907   if (t2 == error_mark_node)
 908     return false;
 909
 910   my_friendly_assert (TYPE_P (t1) && TYPE_P (t2), 20030623);
 911
 912   /* TYPENAME_TYPEs should be resolved if the qualifying scope is the
 913      current instantiation.  */
 914   if (TREE_CODE (t1) == TYPENAME_TYPE)
 915     {
 916       tree resolved = resolve_typename_type (t1, /*only_current_p=*/true);
 917
 918       if (resolved != error_mark_node)
 919         t1 = resolved;
 920     }
 921
 922   if (TREE_CODE (t2) == TYPENAME_TYPE)
 923     {
 924       tree resolved = resolve_typename_type (t2, /*only_current_p=*/true);
 925
 926       if (resolved != error_mark_node)
 927         t2 = resolved;
 928     }
 929
 930   /* If either type is the internal version of sizetype, use the
 931      language version.  */
 932   if (TREE_CODE (t1) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t1)
 933       && TYPE_DOMAIN (t1))
 934     t1 = TYPE_DOMAIN (t1);
 935
 936   if (TREE_CODE (t2) == INTEGER_TYPE && TYPE_IS_SIZETYPE (t2)
 937       && TYPE_DOMAIN (t2))
 938     t2 = TYPE_DOMAIN (t2);
 939
 940   if (TYPE_PTRMEMFUNC_P (t1))
 941     t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1);
 942   if (TYPE_PTRMEMFUNC_P (t2))
 943     t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2);
 944
 945   /* Different classes of types can't be compatible.  */
 946   if (TREE_CODE (t1) != TREE_CODE (t2))
 947     return false;
 948
 949   /* Qualifiers must match.  */
 950   if (cp_type_quals (t1) != cp_type_quals (t2))
 951     return false;
 952   if (TYPE_FOR_JAVA (t1) != TYPE_FOR_JAVA (t2))
 953     return false;
 954
 955   /* Allow for two different type nodes which have essentially the same
 956      definition.  Note that we already checked for equality of the type
 957      qualifiers (just above).  */
 958
 959   if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
 960     return true;
 961
 962   if (!(*targetm.comp_type_attributes) (t1, t2))
 963     return false;
 964
 965   switch (TREE_CODE (t1))
 966     {
 967     case TEMPLATE_TEMPLATE_PARM:
 968     case BOUND_TEMPLATE_TEMPLATE_PARM:
 969       if (TEMPLATE_TYPE_IDX (t1) != TEMPLATE_TYPE_IDX (t2)
 970           || TEMPLATE_TYPE_LEVEL (t1) != TEMPLATE_TYPE_LEVEL (t2))
 971         return false;
 972       if (!comp_template_parms
 973           (DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t1)),
 974            DECL_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t2))))
 975         return false;
 976       if (TREE_CODE (t1) == TEMPLATE_TEMPLATE_PARM)
 977         return true;
 978       /* Don't check inheritance.  */
 979       strict = COMPARE_STRICT;
 980       /* fall through */
 981
 982     case RECORD_TYPE:
 983     case UNION_TYPE:
 984       if (TYPE_TEMPLATE_INFO (t1) && TYPE_TEMPLATE_INFO (t2)
 985           && (TYPE_TI_TEMPLATE (t1) == TYPE_TI_TEMPLATE (t2)
 986               || TREE_CODE (t1) == BOUND_TEMPLATE_TEMPLATE_PARM)
 987           && comp_template_args (TYPE_TI_ARGS (t1), TYPE_TI_ARGS (t2)))
 988         return true;
 989
 990       if ((strict & COMPARE_BASE) && DERIVED_FROM_P (t1, t2))
 991         return true;
 992       else if ((strict & COMPARE_DERIVED) && DERIVED_FROM_P (t2, t1))
 993         return true;
 994
 995       return false;
 996
 997     case OFFSET_TYPE:
 998       if (!comptypes (TYPE_OFFSET_BASETYPE (t1), TYPE_OFFSET_BASETYPE (t2),
 999                       strict & ~COMPARE_REDECLARATION))
1000         return false;
1001       /* FALLTHROUGH*/
1002
1003     case POINTER_TYPE:
1004     case REFERENCE_TYPE:
1005       return same_type_p (TREE_TYPE (t1), TREE_TYPE (t2));
1006
1007     case METHOD_TYPE:
1008     case FUNCTION_TYPE:
1009       if (!same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
1010         return false;
1011       return compparms (TYPE_ARG_TYPES (t1), TYPE_ARG_TYPES (t2));
1012
1013     case ARRAY_TYPE:
1014       /* Target types must match incl. qualifiers.  */
1015       return comp_array_types (t1, t2, !!(strict & COMPARE_REDECLARATION));
1016
1017     case TEMPLATE_TYPE_PARM:
1018       return (TEMPLATE_TYPE_IDX (t1) == TEMPLATE_TYPE_IDX (t2)
1019               && TEMPLATE_TYPE_LEVEL (t1) == TEMPLATE_TYPE_LEVEL (t2));
1020
1021     case TYPENAME_TYPE:
1022       if (!cp_tree_equal (TYPENAME_TYPE_FULLNAME (t1),
1023                           TYPENAME_TYPE_FULLNAME (t2)))
1024         return false;
1025       return same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2));
1026
1027     case UNBOUND_CLASS_TEMPLATE:
1028       if (!cp_tree_equal (TYPE_IDENTIFIER (t1), TYPE_IDENTIFIER (t2)))
1029         return false;
1030       return same_type_p (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2));
1031
1032     case COMPLEX_TYPE:
1033       return same_type_p (TREE_TYPE (t1), TREE_TYPE (t2));
1034
1035     default:
1036       break;
1037     }
1038   return false;
1039 }
1040
1041 /* Returns 1 if TYPE1 is at least as qualified as TYPE2.  */
1042
1043 bool
1044 at_least_as_qualified_p (tree type1, tree type2)
1045 {
1046   int q1 = cp_type_quals (type1);
1047   int q2 = cp_type_quals (type2);
1048
1049   /* All qualifiers for TYPE2 must also appear in TYPE1.  */
1050   return (q1 & q2) == q2;
1051 }
1052
1053 /* Returns 1 if TYPE1 is more qualified than TYPE2.  */
1054
1055 bool
1056 more_qualified_p (tree type1, tree type2)
1057 {
1058   int q1 = cp_type_quals (type1);
1059   int q2 = cp_type_quals (type2);
1060
1061   return q1 != q2 && (q1 & q2) == q2;
1062 }
1063
1064 /* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is
1065    more cv-qualified that TYPE1, and 0 otherwise.  */
1066
1067 int
1068 comp_cv_qualification (tree type1, tree type2)
1069 {
1070   int q1 = cp_type_quals (type1);
1071   int q2 = cp_type_quals (type2);
1072
1073   if (q1 == q2)
1074     return 0;
1075
1076   if ((q1 & q2) == q2)
1077     return 1;
1078   else if ((q1 & q2) == q1)
1079     return -1;
1080
1081   return 0;
1082 }
1083
1084 /* Returns 1 if the cv-qualification signature of TYPE1 is a proper
1085    subset of the cv-qualification signature of TYPE2, and the types
1086    are similar.  Returns -1 if the other way 'round, and 0 otherwise.  */
1087
1088 int
1089 comp_cv_qual_signature (tree type1, tree type2)
1090 {
1091   if (comp_ptr_ttypes_real (type2, type1, -1))
1092     return 1;
1093   else if (comp_ptr_ttypes_real (type1, type2, -1))
1094     return -1;
1095   else
1096     return 0;
1097 }
1098
1099 /* If two types share a common base type, return that basetype.
1100    If there is not a unique most-derived base type, this function
1101    returns ERROR_MARK_NODE.  */
1102
1103 static tree
1104 common_base_type (tree tt1, tree tt2)
1105 {
1106   tree best = NULL_TREE;
1107   int i;
1108
1109   /* If one is a baseclass of another, that's good enough.  */
1110   if (UNIQUELY_DERIVED_FROM_P (tt1, tt2))
1111     return tt1;
1112   if (UNIQUELY_DERIVED_FROM_P (tt2, tt1))
1113     return tt2;
1114
1115   /* Otherwise, try to find a unique baseclass of TT1
1116      that is shared by TT2, and follow that down.  */
1117   for (i = CLASSTYPE_N_BASECLASSES (tt1)-1; i >= 0; i--)
1118     {
1119       tree basetype = TYPE_BINFO_BASETYPE (tt1, i);
1120       tree trial = common_base_type (basetype, tt2);
1121       if (trial)
1122         {
1123           if (trial == error_mark_node)
1124             return trial;
1125           if (best == NULL_TREE)
1126             best = trial;
1127           else if (best != trial)
1128             return error_mark_node;
1129         }
1130     }
1131
1132   /* Same for TT2.  */
1133   for (i = CLASSTYPE_N_BASECLASSES (tt2)-1; i >= 0; i--)
1134     {
1135       tree basetype = TYPE_BINFO_BASETYPE (tt2, i);
1136       tree trial = common_base_type (tt1, basetype);
1137       if (trial)
1138         {
1139           if (trial == error_mark_node)
1140             return trial;
1141           if (best == NULL_TREE)
1142             best = trial;
1143           else if (best != trial)
1144             return error_mark_node;
1145         }
1146     }
1147   return best;
1148 }
1149 \f
1150 /* Subroutines of `comptypes'.  */
1151
1152 /* Return true if two parameter type lists PARMS1 and PARMS2 are
1153    equivalent in the sense that functions with those parameter types
1154    can have equivalent types.  The two lists must be equivalent,
1155    element by element.  */
1156
1157 bool
1158 compparms (tree parms1, tree parms2)
1159 {
1160   tree t1, t2;
1161
1162   /* An unspecified parmlist matches any specified parmlist
1163      whose argument types don't need default promotions.  */
1164
1165   for (t1 = parms1, t2 = parms2;
1166        t1 || t2;
1167        t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
1168     {
1169       /* If one parmlist is shorter than the other,
1170          they fail to match.  */
1171       if (!t1 || !t2)
1172         return false;
1173       if (!same_type_p (TREE_VALUE (t2), TREE_VALUE (t1)))
1174         return false;
1175     }
1176   return true;
1177 }
1178
1179 \f
1180 /* Process a sizeof or alignof expression where the operand is a
1181    type.  */
1182
1183 tree
1184 cxx_sizeof_or_alignof_type (tree type, enum tree_code op, bool complain)
1185 {
1186   enum tree_code type_code;
1187   tree value;
1188   const char *op_name;
1189
1190   my_friendly_assert (op == SIZEOF_EXPR || op == ALIGNOF_EXPR, 20020720);
1191   if (type == error_mark_node)
1192     return error_mark_node;
1193
1194   if (processing_template_decl)
1195     {
1196       value = build_min (op, size_type_node, type);
1197       TREE_READONLY (value) = 1;
1198       return value;
1199     }
1200
1201   op_name = operator_name_info[(int) op].name;
1202
1203   type = non_reference (type);
1204   type_code = TREE_CODE (type);
1205
1206   if (type_code == METHOD_TYPE)
1207     {
1208       if (complain && (pedantic || warn_pointer_arith))
1209         pedwarn ("invalid application of `%s' to a member function", op_name);
1210       value = size_one_node;
1211     }
1212   else
1213     value = c_sizeof_or_alignof_type (complete_type (type), op, complain);
1214
1215   return value;
1216 }
1217
1218 /* Process a sizeof or alignof expression where the operand is an
1219    expression.  */
1220
1221 tree
1222 cxx_sizeof_or_alignof_expr (tree e, enum tree_code op)
1223 {
1224   const char *op_name = operator_name_info[(int) op].name;
1225
1226   if (e == error_mark_node)
1227     return error_mark_node;
1228
1229   if (processing_template_decl)
1230     {
1231       e = build_min (op, size_type_node, e);
1232       TREE_SIDE_EFFECTS (e) = 0;
1233       TREE_READONLY (e) = 1;
1234
1235       return e;
1236     }
1237
1238   if (TREE_CODE (e) == COMPONENT_REF
1239       && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1)))
1240     {
1241       error ("invalid application of `%s' to a bit-field", op_name);
1242       e = char_type_node;
1243     }
1244   else if (is_overloaded_fn (e))
1245     {
1246       pedwarn ("ISO C++ forbids applying `%s' to an expression of function type", op_name);
1247       e = char_type_node;
1248     }
1249   else if (type_unknown_p (e))
1250     {
1251       cxx_incomplete_type_error (e, TREE_TYPE (e));
1252       e = char_type_node;
1253     }
1254   else
1255     e = TREE_TYPE (e);
1256
1257   return cxx_sizeof_or_alignof_type (e, op, true);
1258 }
1259
1260 \f
1261 /* Perform the conversions in [expr] that apply when an lvalue appears
1262    in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and
1263    function-to-pointer conversions.
1264
1265    In addition manifest constants are replaced by their values.  */
1266
1267 tree
1268 decay_conversion (tree exp)
1269 {
1270   register tree type;
1271   register enum tree_code code;
1272
1273   type = TREE_TYPE (exp);
1274   code = TREE_CODE (type);
1275
1276   if (code == REFERENCE_TYPE)
1277     {
1278       exp = convert_from_reference (exp);
1279       type = TREE_TYPE (exp);
1280       code = TREE_CODE (type);
1281     }
1282
1283   if (type == error_mark_node)
1284     return error_mark_node;
1285
1286   if (type_unknown_p (exp))
1287     {
1288       cxx_incomplete_type_error (exp, TREE_TYPE (exp));
1289       return error_mark_node;
1290     }
1291
1292   /* Constants can be used directly unless they're not loadable.  */
1293   if (TREE_CODE (exp) == CONST_DECL)
1294     exp = DECL_INITIAL (exp);
1295   /* Replace a nonvolatile const static variable with its value.  We
1296      don't do this for arrays, though; we want the address of the
1297      first element of the array, not the address of the first element
1298      of its initializing constant.  */
1299   else if (code != ARRAY_TYPE)
1300     {
1301       exp = decl_constant_value (exp);
1302       type = TREE_TYPE (exp);
1303     }
1304
1305   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
1306      Leave such NOP_EXPRs, since RHS is being used in non-lvalue context.  */
1307
1308   if (code == VOID_TYPE)
1309     {
1310       error ("void value not ignored as it ought to be");
1311       return error_mark_node;
1312     }
1313   if (code == METHOD_TYPE)
1314     {
1315       error ("invalid use of non-static member function");
1316       return error_mark_node;
1317     }
1318   if (code == FUNCTION_TYPE || is_overloaded_fn (exp))
1319     return build_unary_op (ADDR_EXPR, exp, 0);
1320   if (code == ARRAY_TYPE)
1321     {
1322       register tree adr;
1323       tree ptrtype;
1324
1325       if (TREE_CODE (exp) == INDIRECT_REF)
1326         return build_nop (build_pointer_type (TREE_TYPE (type)),
1327                           TREE_OPERAND (exp, 0));
1328
1329       if (TREE_CODE (exp) == COMPOUND_EXPR)
1330         {
1331           tree op1 = decay_conversion (TREE_OPERAND (exp, 1));
1332           return build (COMPOUND_EXPR, TREE_TYPE (op1),
1333                         TREE_OPERAND (exp, 0), op1);
1334         }
1335
1336       if (!lvalue_p (exp)
1337           && ! (TREE_CODE (exp) == CONSTRUCTOR && TREE_STATIC (exp)))
1338         {
1339           error ("invalid use of non-lvalue array");
1340           return error_mark_node;
1341         }
1342
1343       ptrtype = build_pointer_type (TREE_TYPE (type));
1344
1345       if (TREE_CODE (exp) == VAR_DECL)
1346         {
1347           /* ??? This is not really quite correct
1348              in that the type of the operand of ADDR_EXPR
1349              is not the target type of the type of the ADDR_EXPR itself.
1350              Question is, can this lossage be avoided?  */
1351           adr = build1 (ADDR_EXPR, ptrtype, exp);
1352           if (!cxx_mark_addressable (exp))
1353             return error_mark_node;
1354           TREE_CONSTANT (adr) = staticp (exp);
1355           TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
1356           return adr;
1357         }
1358       /* This way is better for a COMPONENT_REF since it can
1359          simplify the offset for a component.  */
1360       adr = build_unary_op (ADDR_EXPR, exp, 1);
1361       return cp_convert (ptrtype, adr);
1362     }
1363
1364   /* [basic.lval]: Class rvalues can have cv-qualified types; non-class
1365      rvalues always have cv-unqualified types.  */
1366   if (! CLASS_TYPE_P (type))
1367     exp = cp_convert (TYPE_MAIN_VARIANT (type), exp);
1368
1369   return exp;
1370 }
1371
1372 tree
1373 default_conversion (tree exp)
1374 {
1375   exp = decay_conversion (exp);
1376
1377   if (INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (exp)))
1378     exp = perform_integral_promotions (exp);
1379
1380   return exp;
1381 }
1382
1383 /* EXPR is an expression with an integral or enumeration type.
1384    Perform the integral promotions in [conv.prom], and return the
1385    converted value.  */
1386
1387 tree
1388 perform_integral_promotions (tree expr)
1389 {
1390   tree type;
1391   tree promoted_type;
1392
1393   type = TREE_TYPE (expr);
1394   my_friendly_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type), 20030703);
1395   promoted_type = type_promotes_to (type);
1396   if (type != promoted_type)
1397     expr = cp_convert (promoted_type, expr);
1398   return expr;
1399 }
1400
1401 /* Take the address of an inline function without setting TREE_ADDRESSABLE
1402    or TREE_USED.  */
1403
1404 tree
1405 inline_conversion (tree exp)
1406 {
1407   if (TREE_CODE (exp) == FUNCTION_DECL)
1408     exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
1409
1410   return exp;
1411 }
1412
1413 /* Returns nonzero iff exp is a STRING_CST or the result of applying
1414    decay_conversion to one.  */
1415
1416 int
1417 string_conv_p (tree totype, tree exp, int warn)
1418 {
1419   tree t;
1420
1421   if (! flag_const_strings || TREE_CODE (totype) != POINTER_TYPE)
1422     return 0;
1423
1424   t = TREE_TYPE (totype);
1425   if (!same_type_p (t, char_type_node)
1426       && !same_type_p (t, wchar_type_node))
1427     return 0;
1428
1429   if (TREE_CODE (exp) == STRING_CST)
1430     {
1431       /* Make sure that we don't try to convert between char and wchar_t.  */
1432       if (!same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (exp))), t))
1433         return 0;
1434     }
1435   else
1436     {
1437       /* Is this a string constant which has decayed to 'const char *'?  */
1438       t = build_pointer_type (build_qualified_type (t, TYPE_QUAL_CONST));
1439       if (!same_type_p (TREE_TYPE (exp), t))
1440         return 0;
1441       STRIP_NOPS (exp);
1442       if (TREE_CODE (exp) != ADDR_EXPR
1443           || TREE_CODE (TREE_OPERAND (exp, 0)) != STRING_CST)
1444         return 0;
1445     }
1446
1447   /* This warning is not very useful, as it complains about printf.  */
1448   if (warn && warn_write_strings)
1449     warning ("deprecated conversion from string constant to `%T'", totype);
1450
1451   return 1;
1452 }
1453
1454 /* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we
1455    can, for example, use as an lvalue.  This code used to be in
1456    unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c'
1457    expressions, where we're dealing with aggregates.  But now it's again only
1458    called from unary_complex_lvalue.  The case (in particular) that led to
1459    this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd
1460    get it there.  */
1461
1462 static tree
1463 rationalize_conditional_expr (enum tree_code code, tree t)
1464 {
1465   /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that
1466      the first operand is always the one to be used if both operands
1467      are equal, so we know what conditional expression this used to be.  */
1468   if (TREE_CODE (t) == MIN_EXPR || TREE_CODE (t) == MAX_EXPR)
1469     {
1470       return
1471         build_conditional_expr (build_x_binary_op ((TREE_CODE (t) == MIN_EXPR
1472                                                     ? LE_EXPR : GE_EXPR),
1473                                                    TREE_OPERAND (t, 0),
1474                                                    TREE_OPERAND (t, 1)),
1475                             build_unary_op (code, TREE_OPERAND (t, 0), 0),
1476                             build_unary_op (code, TREE_OPERAND (t, 1), 0));
1477     }
1478
1479   return
1480     build_conditional_expr (TREE_OPERAND (t, 0),
1481                             build_unary_op (code, TREE_OPERAND (t, 1), 0),
1482                             build_unary_op (code, TREE_OPERAND (t, 2), 0));
1483 }
1484
1485 /* Given the TYPE of an anonymous union field inside T, return the
1486    FIELD_DECL for the field.  If not found return NULL_TREE.  Because
1487    anonymous unions can nest, we must also search all anonymous unions
1488    that are directly reachable.  */
1489
1490 static tree
1491 lookup_anon_field (tree t, tree type)
1492 {
1493   tree field;
1494
1495   for (field = TYPE_FIELDS (t); field; field = TREE_CHAIN (field))
1496     {
1497       if (TREE_STATIC (field))
1498         continue;
1499       if (TREE_CODE (field) != FIELD_DECL || DECL_ARTIFICIAL (field))
1500         continue;
1501
1502       /* If we find it directly, return the field.  */
1503       if (DECL_NAME (field) == NULL_TREE
1504           && type == TYPE_MAIN_VARIANT (TREE_TYPE (field)))
1505         {
1506           return field;
1507         }
1508
1509       /* Otherwise, it could be nested, search harder.  */
1510       if (DECL_NAME (field) == NULL_TREE
1511           && ANON_AGGR_TYPE_P (TREE_TYPE (field)))
1512         {
1513           tree subfield = lookup_anon_field (TREE_TYPE (field), type);
1514           if (subfield)
1515             return subfield;
1516         }
1517     }
1518   return NULL_TREE;
1519 }
1520
1521 /* Build an expression representing OBJECT.MEMBER.  OBJECT is an
1522    expression; MEMBER is a DECL or baselink.  If ACCESS_PATH is
1523    non-NULL, it indicates the path to the base used to name MEMBER.
1524    If PRESERVE_REFERENCE is true, the expression returned will have
1525    REFERENCE_TYPE if the MEMBER does.  Otherwise, the expression
1526    returned will have the type referred to by the reference.
1527
1528    This function does not perform access control; that is either done
1529    earlier by the parser when the name of MEMBER is resolved to MEMBER
1530    itself, or later when overload resolution selects one of the
1531    functions indicated by MEMBER.  */
1532
1533 tree
1534 build_class_member_access_expr (tree object, tree member,
1535                                 tree access_path, bool preserve_reference)
1536 {
1537   tree object_type;
1538   tree member_scope;
1539   tree result = NULL_TREE;
1540
1541   if (object == error_mark_node || member == error_mark_node)
1542     return error_mark_node;
1543
1544   if (TREE_CODE (member) == PSEUDO_DTOR_EXPR)
1545     return member;
1546
1547   my_friendly_assert (DECL_P (member) || BASELINK_P (member),
1548                       20020801);
1549
1550   /* [expr.ref]
1551
1552      The type of the first expression shall be "class object" (of a
1553      complete type).  */
1554   object_type = TREE_TYPE (object);
1555   if (!complete_type_or_else (object_type, object))
1556     return error_mark_node;
1557   if (!CLASS_TYPE_P (object_type))
1558     {
1559       error ("request for member `%D' in `%E', which is of non-class type `%T'",
1560              member, object, object_type);
1561       return error_mark_node;
1562     }
1563
1564   /* The standard does not seem to actually say that MEMBER must be a
1565      member of OBJECT_TYPE.  However, that is clearly what is
1566      intended.  */
1567   if (DECL_P (member))
1568     {
1569       member_scope = DECL_CLASS_CONTEXT (member);
1570       mark_used (member);
1571       if (TREE_DEPRECATED (member))
1572         warn_deprecated_use (member);
1573     }
1574   else
1575     member_scope = BINFO_TYPE (BASELINK_BINFO (member));
1576   /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will
1577      presently be the anonymous union.  Go outwards until we find a
1578      type related to OBJECT_TYPE.  */
1579   while (ANON_AGGR_TYPE_P (member_scope)
1580          && !same_type_ignoring_top_level_qualifiers_p (member_scope,
1581                                                         object_type))
1582     member_scope = TYPE_CONTEXT (member_scope);
1583   if (!member_scope || !DERIVED_FROM_P (member_scope, object_type))
1584     {
1585       if (TREE_CODE (member) == FIELD_DECL)
1586         error ("invalid use of nonstatic data member '%E'", member);
1587       else
1588         error ("`%D' is not a member of `%T'", member, object_type);
1589       return error_mark_node;
1590     }
1591
1592   /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into
1593      `(*(a ?  &b : &c)).x', and so on.  A COND_EXPR is only an lvalue
1594      in the frontend; only _DECLs and _REFs are lvalues in the backend.  */
1595   {
1596     tree temp = unary_complex_lvalue (ADDR_EXPR, object);
1597     if (temp)
1598       object = build_indirect_ref (temp, NULL);
1599   }
1600
1601   /* In [expr.ref], there is an explicit list of the valid choices for
1602      MEMBER.  We check for each of those cases here.  */
1603   if (TREE_CODE (member) == VAR_DECL)
1604     {
1605       /* A static data member.  */
1606       result = member;
1607       /* If OBJECT has side-effects, they are supposed to occur.  */
1608       if (TREE_SIDE_EFFECTS (object))
1609         result = build (COMPOUND_EXPR, TREE_TYPE (result), object, result);
1610     }
1611   else if (TREE_CODE (member) == FIELD_DECL)
1612     {
1613       /* A non-static data member.  */
1614       bool null_object_p;
1615       int type_quals;
1616       tree member_type;
1617
1618       null_object_p = (TREE_CODE (object) == INDIRECT_REF
1619                        && integer_zerop (TREE_OPERAND (object, 0)));
1620
1621       /* Convert OBJECT to the type of MEMBER.  */
1622       if (!same_type_p (TYPE_MAIN_VARIANT (object_type),
1623                         TYPE_MAIN_VARIANT (member_scope)))
1624         {
1625           tree binfo;
1626           base_kind kind;
1627
1628           binfo = lookup_base (access_path ? access_path : object_type,
1629                                member_scope, ba_ignore,  &kind);
1630           if (binfo == error_mark_node)
1631             return error_mark_node;
1632
1633           /* It is invalid to try to get to a virtual base of a
1634              NULL object.  The most common cause is invalid use of
1635              offsetof macro.  */
1636           if (null_object_p && kind == bk_via_virtual)
1637             {
1638               error ("invalid access to non-static data member `%D' of NULL object",
1639                      member);
1640               error ("(perhaps the `offsetof' macro was used incorrectly)");
1641               return error_mark_node;
1642             }
1643
1644           /* Convert to the base.  */
1645           object = build_base_path (PLUS_EXPR, object, binfo,
1646                                     /*nonnull=*/1);
1647           /* If we found the base successfully then we should be able
1648              to convert to it successfully.  */
1649           my_friendly_assert (object != error_mark_node,
1650                               20020801);
1651         }
1652
1653       /* Complain about other invalid uses of offsetof, even though they will
1654          give the right answer.  Note that we complain whether or not they
1655          actually used the offsetof macro, since there's no way to know at this
1656          point.  So we just give a warning, instead of a pedwarn.  */
1657       if (null_object_p && warn_invalid_offsetof
1658           && CLASSTYPE_NON_POD_P (object_type))
1659         {
1660           warning ("invalid access to non-static data member `%D' of NULL object",
1661                    member);
1662           warning  ("(perhaps the `offsetof' macro was used incorrectly)");
1663         }
1664
1665       /* If MEMBER is from an anonymous aggregate, we have converted
1666          OBJECT so that it refers to the class containing the
1667          anonymous union.  Generate a reference to the anonymous union
1668          itself, and recur to find MEMBER.  */
1669       if (ANON_AGGR_TYPE_P (DECL_CONTEXT (member))
1670           /* When this code is called from build_field_call, the
1671              object already has the type of the anonymous union.
1672              That is because the COMPONENT_REF was already
1673              constructed, and was then disassembled before calling
1674              build_field_call.  After the function-call code is
1675              cleaned up, this waste can be eliminated.  */
1676           && (!same_type_ignoring_top_level_qualifiers_p
1677               (TREE_TYPE (object), DECL_CONTEXT (member))))
1678         {
1679           tree anonymous_union;
1680
1681           anonymous_union = lookup_anon_field (TREE_TYPE (object),
1682                                                DECL_CONTEXT (member));
1683           object = build_class_member_access_expr (object,
1684                                                    anonymous_union,
1685                                                    /*access_path=*/NULL_TREE,
1686                                                    preserve_reference);
1687         }
1688
1689       /* Compute the type of the field, as described in [expr.ref].  */
1690       type_quals = TYPE_UNQUALIFIED;
1691       member_type = TREE_TYPE (member);
1692       if (TREE_CODE (member_type) != REFERENCE_TYPE)
1693         {
1694           type_quals = (cp_type_quals (member_type)
1695                         | cp_type_quals (object_type));
1696
1697           /* A field is const (volatile) if the enclosing object, or the
1698              field itself, is const (volatile).  But, a mutable field is
1699              not const, even within a const object.  */
1700           if (DECL_MUTABLE_P (member))
1701             type_quals &= ~TYPE_QUAL_CONST;
1702           member_type = cp_build_qualified_type (member_type, type_quals);
1703         }
1704
1705       result = fold (build (COMPONENT_REF, member_type, object, member));
1706
1707       /* Mark the expression const or volatile, as appropriate.  Even
1708          though we've dealt with the type above, we still have to mark the
1709          expression itself.  */
1710       if (type_quals & TYPE_QUAL_CONST)
1711         TREE_READONLY (result) = 1;
1712       else if (type_quals & TYPE_QUAL_VOLATILE)
1713         TREE_THIS_VOLATILE (result) = 1;
1714     }
1715   else if (BASELINK_P (member))
1716     {
1717       /* The member is a (possibly overloaded) member function.  */
1718       tree functions;
1719       tree type;
1720
1721       /* If the MEMBER is exactly one static member function, then we
1722          know the type of the expression.  Otherwise, we must wait
1723          until overload resolution has been performed.  */
1724       functions = BASELINK_FUNCTIONS (member);
1725       if (TREE_CODE (functions) == FUNCTION_DECL
1726           && DECL_STATIC_FUNCTION_P (functions))
1727         type = TREE_TYPE (functions);
1728       else
1729         type = unknown_type_node;
1730       /* Note that we do not convert OBJECT to the BASELINK_BINFO
1731          base.  That will happen when the function is called.  */
1732       result = build (COMPONENT_REF, type, object, member);
1733     }
1734   else if (TREE_CODE (member) == CONST_DECL)
1735     {
1736       /* The member is an enumerator.  */
1737       result = member;
1738       /* If OBJECT has side-effects, they are supposed to occur.  */
1739       if (TREE_SIDE_EFFECTS (object))
1740         result = build (COMPOUND_EXPR, TREE_TYPE (result),
1741                         object, result);
1742     }
1743   else
1744     {
1745       error ("invalid use of `%D'", member);
1746       return error_mark_node;
1747     }
1748
1749   if (!preserve_reference)
1750     /* [expr.ref]
1751
1752        If E2 is declared to have type "reference to T", then ... the
1753        type of E1.E2 is T.  */
1754     result = convert_from_reference (result);
1755
1756   return result;
1757 }
1758
1759 /* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if
1760    SCOPE is NULL, by OBJECT.~DTOR_NAME.  */
1761
1762 static tree
1763 lookup_destructor (tree object, tree scope, tree dtor_name)
1764 {
1765   tree object_type = TREE_TYPE (object);
1766   tree dtor_type = TREE_OPERAND (dtor_name, 0);
1767
1768   if (scope && !check_dtor_name (scope, dtor_name))
1769     {
1770       error ("qualified type `%T' does not match destructor name `~%T'",
1771              scope, dtor_type);
1772       return error_mark_node;
1773     }
1774   if (!same_type_p (dtor_type, TYPE_MAIN_VARIANT (object_type)))
1775     {
1776       error ("destructor name `%T' does not match type `%T' of expression",
1777              dtor_type, object_type);
1778       return error_mark_node;
1779     }
1780   if (!TYPE_HAS_DESTRUCTOR (object_type))
1781     return build (PSEUDO_DTOR_EXPR, void_type_node, object, scope,
1782                   dtor_type);
1783   return lookup_member (object_type, complete_dtor_identifier,
1784                         /*protect=*/1, /*want_type=*/false);
1785 }
1786
1787 /* This function is called by the parser to process a class member
1788    access expression of the form OBJECT.NAME.  NAME is a node used by
1789    the parser to represent a name; it is not yet a DECL.  It may,
1790    however, be a BASELINK where the BASELINK_FUNCTIONS is a
1791    TEMPLATE_ID_EXPR.  Templates must be looked up by the parser, and
1792    there is no reason to do the lookup twice, so the parser keeps the
1793    BASELINK.  */
1794
1795 tree
1796 finish_class_member_access_expr (tree object, tree name)
1797 {
1798   tree expr;
1799   tree object_type;
1800   tree member;
1801   tree access_path = NULL_TREE;
1802   tree orig_object = object;
1803   tree orig_name = name;
1804
1805   if (object == error_mark_node || name == error_mark_node)
1806     return error_mark_node;
1807
1808   object_type = TREE_TYPE (object);
1809
1810   if (processing_template_decl)
1811     {
1812       if (/* If OBJECT_TYPE is dependent, so is OBJECT.NAME.  */
1813           dependent_type_p (object_type)
1814           /* If NAME is "f<args>", where either 'f' or 'args' is
1815              dependent, then the expression is dependent.  */
1816           || (TREE_CODE (name) == TEMPLATE_ID_EXPR
1817               && dependent_template_id_p (TREE_OPERAND (name, 0),
1818                                           TREE_OPERAND (name, 1)))
1819           /* If NAME is "T::X" where "T" is dependent, then the
1820              expression is dependent.  */
1821           || (TREE_CODE (name) == SCOPE_REF
1822               && TYPE_P (TREE_OPERAND (name, 0))
1823               && dependent_type_p (TREE_OPERAND (name, 0))))
1824         return build_min_nt (COMPONENT_REF, object, name);
1825       object = build_non_dependent_expr (object);
1826     }
1827
1828   if (TREE_CODE (object_type) == REFERENCE_TYPE)
1829     {
1830       object = convert_from_reference (object);
1831       object_type = TREE_TYPE (object);
1832     }
1833
1834   /* [expr.ref]
1835
1836      The type of the first expression shall be "class object" (of a
1837      complete type).  */
1838   if (!complete_type_or_else (object_type, object))
1839     return error_mark_node;
1840   if (!CLASS_TYPE_P (object_type))
1841     {
1842       error ("request for member `%D' in `%E', which is of non-class type `%T'",
1843              name, object, object_type);
1844       return error_mark_node;
1845     }
1846
1847   if (BASELINK_P (name))
1848     {
1849       /* A member function that has already been looked up.  */
1850       my_friendly_assert ((TREE_CODE (BASELINK_FUNCTIONS (name))
1851                            == TEMPLATE_ID_EXPR),
1852                           20020805);
1853       member = name;
1854     }
1855   else
1856     {
1857       bool is_template_id = false;
1858       tree template_args = NULL_TREE;
1859       tree scope;
1860
1861       if (TREE_CODE (name) == TEMPLATE_ID_EXPR)
1862         {
1863           is_template_id = true;
1864           template_args = TREE_OPERAND (name, 1);
1865           name = TREE_OPERAND (name, 0);
1866         }
1867
1868       if (TREE_CODE (name) == SCOPE_REF)
1869         {
1870           /* A qualified name.  The qualifying class or namespace `S' has
1871              already been looked up; it is either a TYPE or a
1872              NAMESPACE_DECL.  The member name is either an IDENTIFIER_NODE
1873              or a BIT_NOT_EXPR.  */
1874           scope = TREE_OPERAND (name, 0);
1875           name = TREE_OPERAND (name, 1);
1876           my_friendly_assert ((CLASS_TYPE_P (scope)
1877                                || TREE_CODE (scope) == NAMESPACE_DECL),
1878                               20020804);
1879           my_friendly_assert ((TREE_CODE (name) == IDENTIFIER_NODE
1880                                || TREE_CODE (name) == BIT_NOT_EXPR),
1881                               20020804);
1882
1883           /* If SCOPE is a namespace, then the qualified name does not
1884              name a member of OBJECT_TYPE.  */
1885           if (TREE_CODE (scope) == NAMESPACE_DECL)
1886             {
1887               error ("`%D::%D' is not a member of `%T'",
1888                      scope, name, object_type);
1889               return error_mark_node;
1890             }
1891
1892           /* Find the base of OBJECT_TYPE corresponding to SCOPE.  */
1893           access_path = lookup_base (object_type, scope, ba_check, NULL);
1894           if (!access_path || access_path == error_mark_node)
1895             return error_mark_node;
1896         }
1897       else
1898         {
1899           scope = NULL_TREE;
1900           access_path = object_type;
1901         }
1902
1903       if (TREE_CODE (name) == BIT_NOT_EXPR)
1904         member = lookup_destructor (object, scope, name);
1905       else
1906         {
1907           /* Look up the member.  */
1908           member = lookup_member (access_path, name, /*protect=*/1,
1909                                   /*want_type=*/false);
1910           if (member == NULL_TREE)
1911             {
1912               error ("'%D' has no member named '%E'", object_type, name);
1913               return error_mark_node;
1914             }
1915           if (member == error_mark_node)
1916             return error_mark_node;
1917         }
1918
1919       if (is_template_id)
1920         {
1921           tree template = member;
1922
1923           if (BASELINK_P (template))
1924             template = lookup_template_function (template, template_args);
1925           else
1926             {
1927               error ("`%D' is not a member template function", name);
1928               return error_mark_node;
1929             }
1930         }
1931     }
1932
1933   if (TREE_DEPRECATED (member))
1934     warn_deprecated_use (member);
1935
1936   expr = build_class_member_access_expr (object, member, access_path,
1937                                          /*preserve_reference=*/false);
1938   if (processing_template_decl && expr != error_mark_node)
1939     return build_min_non_dep (COMPONENT_REF, expr,
1940                               orig_object, orig_name);
1941   return expr;
1942 }
1943
1944 /* Return an expression for the MEMBER_NAME field in the internal
1945    representation of PTRMEM, a pointer-to-member function.  (Each
1946    pointer-to-member function type gets its own RECORD_TYPE so it is
1947    more convenient to access the fields by name than by FIELD_DECL.)
1948    This routine converts the NAME to a FIELD_DECL and then creates the
1949    node for the complete expression.  */
1950
1951 tree
1952 build_ptrmemfunc_access_expr (tree ptrmem, tree member_name)
1953 {
1954   tree ptrmem_type;
1955   tree member;
1956   tree member_type;
1957
1958   /* This code is a stripped down version of
1959      build_class_member_access_expr.  It does not work to use that
1960      routine directly because it expects the object to be of class
1961      type.  */
1962   ptrmem_type = TREE_TYPE (ptrmem);
1963   my_friendly_assert (TYPE_PTRMEMFUNC_P (ptrmem_type), 20020804);
1964   member = lookup_member (ptrmem_type, member_name, /*protect=*/0,
1965                           /*want_type=*/false);
1966   member_type = cp_build_qualified_type (TREE_TYPE (member),
1967                                          cp_type_quals (ptrmem_type));
1968   return fold (build (COMPONENT_REF, member_type, ptrmem, member));
1969 }
1970
1971 /* Given an expression PTR for a pointer, return an expression
1972    for the value pointed to.
1973    ERRORSTRING is the name of the operator to appear in error messages.
1974
1975    This function may need to overload OPERATOR_FNNAME.
1976    Must also handle REFERENCE_TYPEs for C++.  */
1977
1978 tree
1979 build_x_indirect_ref (tree expr, const char *errorstring)
1980 {
1981   tree orig_expr = expr;
1982   tree rval;
1983
1984   if (processing_template_decl)
1985     {
1986       if (type_dependent_expression_p (expr))
1987         return build_min_nt (INDIRECT_REF, expr);
1988       expr = build_non_dependent_expr (expr);
1989     }
1990
1991   rval = build_new_op (INDIRECT_REF, LOOKUP_NORMAL, expr, NULL_TREE,
1992                        NULL_TREE);
1993   if (!rval)
1994     rval = build_indirect_ref (expr, errorstring);
1995
1996   if (processing_template_decl && rval != error_mark_node)
1997     return build_min_non_dep (INDIRECT_REF, rval, orig_expr);
1998   else
1999     return rval;
2000 }
2001
2002 tree
2003 build_indirect_ref (tree ptr, const char *errorstring)
2004 {
2005   register tree pointer, type;
2006
2007   if (ptr == error_mark_node)
2008     return error_mark_node;
2009
2010   if (ptr == current_class_ptr)
2011     return current_class_ref;
2012
2013   pointer = (TREE_CODE (TREE_TYPE (ptr)) == REFERENCE_TYPE
2014              ? ptr : decay_conversion (ptr));
2015   type = TREE_TYPE (pointer);
2016
2017   if (TYPE_PTR_P (type) || TREE_CODE (type) == REFERENCE_TYPE)
2018     {
2019       /* [expr.unary.op]
2020
2021          If the type of the expression is "pointer to T," the type
2022          of  the  result  is  "T."
2023
2024          We must use the canonical variant because certain parts of
2025          the back end, like fold, do pointer comparisons between
2026          types.  */
2027       tree t = canonical_type_variant (TREE_TYPE (type));
2028
2029       if (VOID_TYPE_P (t))
2030         {
2031           /* A pointer to incomplete type (other than cv void) can be
2032              dereferenced [expr.unary.op]/1  */
2033           error ("`%T' is not a pointer-to-object type", type);
2034           return error_mark_node;
2035         }
2036       else if (TREE_CODE (pointer) == ADDR_EXPR
2037                && same_type_p (t, TREE_TYPE (TREE_OPERAND (pointer, 0))))
2038         /* The POINTER was something like `&x'.  We simplify `*&x' to
2039            `x'.  */
2040         return TREE_OPERAND (pointer, 0);
2041       else
2042         {
2043           tree ref = build1 (INDIRECT_REF, t, pointer);
2044
2045           /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2046              so that we get the proper error message if the result is used
2047              to assign to.  Also, &* is supposed to be a no-op.  */
2048           TREE_READONLY (ref) = CP_TYPE_CONST_P (t);
2049           TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t);
2050           TREE_SIDE_EFFECTS (ref)
2051             = (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (pointer));
2052           return ref;
2053         }
2054     }
2055   /* `pointer' won't be an error_mark_node if we were given a
2056      pointer to member, so it's cool to check for this here.  */
2057   else if (TYPE_PTR_TO_MEMBER_P (type))
2058     error ("invalid use of `%s' on pointer to member", errorstring);
2059   else if (pointer != error_mark_node)
2060     {
2061       if (errorstring)
2062         error ("invalid type argument of `%s'", errorstring);
2063       else
2064         error ("invalid type argument");
2065     }
2066   return error_mark_node;
2067 }
2068
2069 /* This handles expressions of the form "a[i]", which denotes
2070    an array reference.
2071
2072    This is logically equivalent in C to *(a+i), but we may do it differently.
2073    If A is a variable or a member, we generate a primitive ARRAY_REF.
2074    This avoids forcing the array out of registers, and can work on
2075    arrays that are not lvalues (for example, members of structures returned
2076    by functions).
2077
2078    If INDEX is of some user-defined type, it must be converted to
2079    integer type.  Otherwise, to make a compatible PLUS_EXPR, it
2080    will inherit the type of the array, which will be some pointer type.  */
2081
2082 tree
2083 build_array_ref (tree array, tree idx)
2084 {
2085   if (idx == 0)
2086     {
2087       error ("subscript missing in array reference");
2088       return error_mark_node;
2089     }
2090
2091   if (TREE_TYPE (array) == error_mark_node
2092       || TREE_TYPE (idx) == error_mark_node)
2093     return error_mark_node;
2094
2095   /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference
2096      inside it.  */
2097   switch (TREE_CODE (array))
2098     {
2099     case COMPOUND_EXPR:
2100       {
2101         tree value = build_array_ref (TREE_OPERAND (array, 1), idx);
2102         return build (COMPOUND_EXPR, TREE_TYPE (value),
2103                       TREE_OPERAND (array, 0), value);
2104       }
2105
2106     case COND_EXPR:
2107       return build_conditional_expr
2108         (TREE_OPERAND (array, 0),
2109          build_array_ref (TREE_OPERAND (array, 1), idx),
2110          build_array_ref (TREE_OPERAND (array, 2), idx));
2111
2112     default:
2113       break;
2114     }
2115
2116   if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE
2117       && TREE_CODE (array) != INDIRECT_REF)
2118     {
2119       tree rval, type;
2120
2121       /* Subscripting with type char is likely to lose
2122          on a machine where chars are signed.
2123          So warn on any machine, but optionally.
2124          Don't warn for unsigned char since that type is safe.
2125          Don't warn for signed char because anyone who uses that
2126          must have done so deliberately.  */
2127       if (warn_char_subscripts
2128           && TYPE_MAIN_VARIANT (TREE_TYPE (idx)) == char_type_node)
2129         warning ("array subscript has type `char'");
2130
2131       if (!INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (idx)))
2132         {
2133           error ("array subscript is not an integer");
2134           return error_mark_node;
2135         }
2136
2137       /* Apply integral promotions *after* noticing character types.
2138          (It is unclear why we do these promotions -- the standard
2139          does not say that we should.  In fact, the natual thing would
2140          seem to be to convert IDX to ptrdiff_t; we're performing
2141          pointer arithmetic.)  */
2142       idx = perform_integral_promotions (idx);
2143
2144       /* An array that is indexed by a non-constant
2145          cannot be stored in a register; we must be able to do
2146          address arithmetic on its address.
2147          Likewise an array of elements of variable size.  */
2148       if (TREE_CODE (idx) != INTEGER_CST
2149           || (COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (array)))
2150               && (TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array))))
2151                   != INTEGER_CST)))
2152         {
2153           if (!cxx_mark_addressable (array))
2154             return error_mark_node;
2155         }
2156
2157       /* An array that is indexed by a constant value which is not within
2158          the array bounds cannot be stored in a register either; because we
2159          would get a crash in store_bit_field/extract_bit_field when trying
2160          to access a non-existent part of the register.  */
2161       if (TREE_CODE (idx) == INTEGER_CST
2162           && TYPE_VALUES (TREE_TYPE (array))
2163           && ! int_fits_type_p (idx, TYPE_VALUES (TREE_TYPE (array))))
2164         {
2165           if (!cxx_mark_addressable (array))
2166             return error_mark_node;
2167         }
2168
2169       if (pedantic && !lvalue_p (array))
2170         pedwarn ("ISO C++ forbids subscripting non-lvalue array");
2171
2172       /* Note in C++ it is valid to subscript a `register' array, since
2173          it is valid to take the address of something with that
2174          storage specification.  */
2175       if (extra_warnings)
2176         {
2177           tree foo = array;
2178           while (TREE_CODE (foo) == COMPONENT_REF)
2179             foo = TREE_OPERAND (foo, 0);
2180           if (TREE_CODE (foo) == VAR_DECL && DECL_REGISTER (foo))
2181             warning ("subscripting array declared `register'");
2182         }
2183
2184       type = TREE_TYPE (TREE_TYPE (array));
2185       rval = build (ARRAY_REF, type, array, idx);
2186       /* Array ref is const/volatile if the array elements are
2187          or if the array is..  */
2188       TREE_READONLY (rval)
2189         |= (CP_TYPE_CONST_P (type) | TREE_READONLY (array));
2190       TREE_SIDE_EFFECTS (rval)
2191         |= (CP_TYPE_VOLATILE_P (type) | TREE_SIDE_EFFECTS (array));
2192       TREE_THIS_VOLATILE (rval)
2193         |= (CP_TYPE_VOLATILE_P (type) | TREE_THIS_VOLATILE (array));
2194       return require_complete_type (fold (rval));
2195     }
2196
2197   {
2198     tree ar = default_conversion (array);
2199     tree ind = default_conversion (idx);
2200
2201     /* Put the integer in IND to simplify error checking.  */
2202     if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE)
2203       {
2204         tree temp = ar;
2205         ar = ind;
2206         ind = temp;
2207       }
2208
2209     if (ar == error_mark_node)
2210       return ar;
2211
2212     if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE)
2213       {
2214         error ("subscripted value is neither array nor pointer");
2215         return error_mark_node;
2216       }
2217     if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE)
2218       {
2219         error ("array subscript is not an integer");
2220         return error_mark_node;
2221       }
2222
2223     return build_indirect_ref (cp_build_binary_op (PLUS_EXPR, ar, ind),
2224                                "array indexing");
2225   }
2226 }
2227 \f
2228 /* Resolve a pointer to member function.  INSTANCE is the object
2229    instance to use, if the member points to a virtual member.
2230
2231    This used to avoid checking for virtual functions if basetype
2232    has no virtual functions, according to an earlier ANSI draft.
2233    With the final ISO C++ rules, such an optimization is
2234    incorrect: A pointer to a derived member can be static_cast
2235    to pointer-to-base-member, as long as the dynamic object
2236    later has the right member.  */
2237
2238 tree
2239 get_member_function_from_ptrfunc (tree *instance_ptrptr, tree function)
2240 {
2241   if (TREE_CODE (function) == OFFSET_REF)
2242     function = TREE_OPERAND (function, 1);
2243
2244   if (TYPE_PTRMEMFUNC_P (TREE_TYPE (function)))
2245     {
2246       tree idx, delta, e1, e2, e3, vtbl, basetype;
2247       tree fntype = TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (function));
2248
2249       tree instance_ptr = *instance_ptrptr;
2250       tree instance_save_expr = 0;
2251       if (instance_ptr == error_mark_node)
2252         {
2253           if (TREE_CODE (function) == PTRMEM_CST)
2254             {
2255               /* Extracting the function address from a pmf is only
2256                  allowed with -Wno-pmf-conversions. It only works for
2257                  pmf constants.  */
2258               e1 = build_addr_func (PTRMEM_CST_MEMBER (function));
2259               e1 = convert (fntype, e1);
2260               return e1;
2261             }
2262           else
2263             {
2264               error ("object missing in use of `%E'", function);
2265               return error_mark_node;
2266             }
2267         }
2268
2269       if (TREE_SIDE_EFFECTS (instance_ptr))
2270         instance_ptr = instance_save_expr = save_expr (instance_ptr);
2271
2272       if (TREE_SIDE_EFFECTS (function))
2273         function = save_expr (function);
2274
2275       /* Start by extracting all the information from the PMF itself.  */
2276       e3 = PFN_FROM_PTRMEMFUNC (function);
2277       delta = build_ptrmemfunc_access_expr (function, delta_identifier);
2278       idx = build1 (NOP_EXPR, vtable_index_type, e3);
2279       switch (TARGET_PTRMEMFUNC_VBIT_LOCATION)
2280         {
2281         case ptrmemfunc_vbit_in_pfn:
2282           e1 = cp_build_binary_op (BIT_AND_EXPR, idx, integer_one_node);
2283           idx = cp_build_binary_op (MINUS_EXPR, idx, integer_one_node);
2284           break;
2285
2286         case ptrmemfunc_vbit_in_delta:
2287           e1 = cp_build_binary_op (BIT_AND_EXPR, delta, integer_one_node);
2288           delta = cp_build_binary_op (RSHIFT_EXPR, delta, integer_one_node);
2289           break;
2290
2291         default:
2292           abort ();
2293         }
2294
2295       /* Convert down to the right base before using the instance.  First
2296          use the type...  */
2297       basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (fntype));
2298       basetype = lookup_base (TREE_TYPE (TREE_TYPE (instance_ptr)),
2299                               basetype, ba_check, NULL);
2300       instance_ptr = build_base_path (PLUS_EXPR, instance_ptr, basetype, 1);
2301       if (instance_ptr == error_mark_node)
2302         return error_mark_node;
2303       /* ...and then the delta in the PMF.  */
2304       instance_ptr = build (PLUS_EXPR, TREE_TYPE (instance_ptr),
2305                             instance_ptr, delta);
2306
2307       /* Hand back the adjusted 'this' argument to our caller.  */
2308       *instance_ptrptr = instance_ptr;
2309
2310       /* Next extract the vtable pointer from the object.  */
2311       vtbl = build1 (NOP_EXPR, build_pointer_type (vtbl_ptr_type_node),
2312                      instance_ptr);
2313       vtbl = build_indirect_ref (vtbl, NULL);
2314
2315       /* Finally, extract the function pointer from the vtable.  */
2316       e2 = fold (build (PLUS_EXPR, TREE_TYPE (vtbl), vtbl, idx));
2317       e2 = build_indirect_ref (e2, NULL);
2318       TREE_CONSTANT (e2) = 1;
2319
2320       /* When using function descriptors, the address of the
2321          vtable entry is treated as a function pointer.  */
2322       if (TARGET_VTABLE_USES_DESCRIPTORS)
2323         e2 = build1 (NOP_EXPR, TREE_TYPE (e2),
2324                      build_unary_op (ADDR_EXPR, e2, /*noconvert=*/1));
2325
2326       TREE_TYPE (e2) = TREE_TYPE (e3);
2327       e1 = build_conditional_expr (e1, e2, e3);
2328
2329       /* Make sure this doesn't get evaluated first inside one of the
2330          branches of the COND_EXPR.  */
2331       if (instance_save_expr)
2332         e1 = build (COMPOUND_EXPR, TREE_TYPE (e1),
2333                     instance_save_expr, e1);
2334
2335       function = e1;
2336     }
2337   return function;
2338 }
2339
2340 tree
2341 build_function_call (tree function, tree params)
2342 {
2343   register tree fntype, fndecl;
2344   register tree coerced_params;
2345   tree result;
2346   tree name = NULL_TREE, assembler_name = NULL_TREE;
2347   int is_method;
2348   tree original = function;
2349
2350   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2351      Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context.  */
2352   if (TREE_CODE (function) == NOP_EXPR
2353       && TREE_TYPE (function) == TREE_TYPE (TREE_OPERAND (function, 0)))
2354     function = TREE_OPERAND (function, 0);
2355
2356   if (TREE_CODE (function) == FUNCTION_DECL)
2357     {
2358       name = DECL_NAME (function);
2359       assembler_name = DECL_ASSEMBLER_NAME (function);
2360
2361       mark_used (function);
2362       fndecl = function;
2363
2364       /* Convert anything with function type to a pointer-to-function.  */
2365       if (pedantic && DECL_MAIN_P (function))
2366         pedwarn ("ISO C++ forbids calling `::main' from within program");
2367
2368       /* Differs from default_conversion by not setting TREE_ADDRESSABLE
2369          (because calling an inline function does not mean the function
2370          needs to be separately compiled).  */
2371
2372       if (DECL_INLINE (function))
2373         function = inline_conversion (function);
2374       else
2375         function = build_addr_func (function);
2376     }
2377   else
2378     {
2379       fndecl = NULL_TREE;
2380
2381       function = build_addr_func (function);
2382     }
2383
2384   if (function == error_mark_node)
2385     return error_mark_node;
2386
2387   fntype = TREE_TYPE (function);
2388
2389   if (TYPE_PTRMEMFUNC_P (fntype))
2390     {
2391       error ("must use .* or ->* to call pointer-to-member function in `%E (...)'",
2392                 original);
2393       return error_mark_node;
2394     }
2395
2396   is_method = (TREE_CODE (fntype) == POINTER_TYPE
2397                && TREE_CODE (TREE_TYPE (fntype)) == METHOD_TYPE);
2398
2399   if (!((TREE_CODE (fntype) == POINTER_TYPE
2400          && TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE)
2401         || is_method
2402         || TREE_CODE (function) == TEMPLATE_ID_EXPR))
2403     {
2404       error ("`%E' cannot be used as a function", original);
2405       return error_mark_node;
2406     }
2407
2408   /* fntype now gets the type of function pointed to.  */
2409   fntype = TREE_TYPE (fntype);
2410
2411   /* Convert the parameters to the types declared in the
2412      function prototype, or apply default promotions.  */
2413
2414   coerced_params = convert_arguments (TYPE_ARG_TYPES (fntype),
2415                                       params, fndecl, LOOKUP_NORMAL);
2416   if (coerced_params == error_mark_node)
2417     return error_mark_node;
2418
2419   /* Check for errors in format strings.  */
2420
2421   if (warn_format)
2422     check_function_format (NULL, TYPE_ATTRIBUTES (fntype), coerced_params);
2423
2424   /* Recognize certain built-in functions so we can make tree-codes
2425      other than CALL_EXPR.  We do this when it enables fold-const.c
2426      to do something useful.  */
2427
2428   if (TREE_CODE (function) == ADDR_EXPR
2429       && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL
2430       && DECL_BUILT_IN (TREE_OPERAND (function, 0)))
2431     {
2432       result = expand_tree_builtin (TREE_OPERAND (function, 0),
2433                                     params, coerced_params);
2434       if (result)
2435         return result;
2436     }
2437
2438   return build_cxx_call (function, params, coerced_params);
2439 }
2440 \f
2441 /* Convert the actual parameter expressions in the list VALUES
2442    to the types in the list TYPELIST.
2443    If parmdecls is exhausted, or when an element has NULL as its type,
2444    perform the default conversions.
2445
2446    NAME is an IDENTIFIER_NODE or 0.  It is used only for error messages.
2447
2448    This is also where warnings about wrong number of args are generated.
2449
2450    Return a list of expressions for the parameters as converted.
2451
2452    Both VALUES and the returned value are chains of TREE_LIST nodes
2453    with the elements of the list in the TREE_VALUE slots of those nodes.
2454
2455    In C++, unspecified trailing parameters can be filled in with their
2456    default arguments, if such were specified.  Do so here.  */
2457
2458 tree
2459 convert_arguments (tree typelist, tree values, tree fndecl, int flags)
2460 {
2461   register tree typetail, valtail;
2462   register tree result = NULL_TREE;
2463   const char *called_thing = 0;
2464   int i = 0;
2465
2466   /* Argument passing is always copy-initialization.  */
2467   flags |= LOOKUP_ONLYCONVERTING;
2468
2469   if (fndecl)
2470     {
2471       if (TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
2472         {
2473           if (DECL_NAME (fndecl) == NULL_TREE
2474               || IDENTIFIER_HAS_TYPE_VALUE (DECL_NAME (fndecl)))
2475             called_thing = "constructor";
2476           else
2477             called_thing = "member function";
2478         }
2479       else
2480         called_thing = "function";
2481     }
2482
2483   for (valtail = values, typetail = typelist;
2484        valtail;
2485        valtail = TREE_CHAIN (valtail), i++)
2486     {
2487       register tree type = typetail ? TREE_VALUE (typetail) : 0;
2488       register tree val = TREE_VALUE (valtail);
2489
2490       if (val == error_mark_node)
2491         return error_mark_node;
2492
2493       if (type == void_type_node)
2494         {
2495           if (fndecl)
2496             {
2497               cp_error_at ("too many arguments to %s `%+#D'", called_thing,
2498                            fndecl);
2499               error ("at this point in file");
2500             }
2501           else
2502             error ("too many arguments to function");
2503           /* In case anybody wants to know if this argument
2504              list is valid.  */
2505           if (result)
2506             TREE_TYPE (tree_last (result)) = error_mark_node;
2507           break;
2508         }
2509
2510       /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2511          Strip such NOP_EXPRs, since VAL is used in non-lvalue context.  */
2512       if (TREE_CODE (val) == NOP_EXPR
2513           && TREE_TYPE (val) == TREE_TYPE (TREE_OPERAND (val, 0))
2514           && (type == 0 || TREE_CODE (type) != REFERENCE_TYPE))
2515         val = TREE_OPERAND (val, 0);
2516
2517       if (type == 0 || TREE_CODE (type) != REFERENCE_TYPE)
2518         {
2519           if (TREE_CODE (TREE_TYPE (val)) == ARRAY_TYPE
2520               || TREE_CODE (TREE_TYPE (val)) == FUNCTION_TYPE
2521               || TREE_CODE (TREE_TYPE (val)) == METHOD_TYPE)
2522             val = decay_conversion (val);
2523         }
2524
2525       if (val == error_mark_node)
2526         return error_mark_node;
2527
2528       if (type != 0)
2529         {
2530           /* Formal parm type is specified by a function prototype.  */
2531           tree parmval;
2532
2533           if (!COMPLETE_TYPE_P (complete_type (type)))
2534             {
2535               error ("parameter type of called function is incomplete");
2536               parmval = val;
2537             }
2538           else
2539             {
2540               parmval = convert_for_initialization
2541                 (NULL_TREE, type, val, flags,
2542                  "argument passing", fndecl, i);
2543               parmval = convert_for_arg_passing (type, parmval);
2544             }
2545
2546           if (parmval == error_mark_node)
2547             return error_mark_node;
2548
2549           result = tree_cons (NULL_TREE, parmval, result);
2550         }
2551       else
2552         {
2553           if (TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE)
2554             val = convert_from_reference (val);
2555
2556           if (fndecl && DECL_BUILT_IN (fndecl)
2557               && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P)
2558             /* Don't do ellipsis conversion for __built_in_constant_p
2559                as this will result in spurious warnings for non-POD
2560                types.  */
2561             val = require_complete_type (val);
2562           else
2563             val = convert_arg_to_ellipsis (val);
2564
2565           result = tree_cons (NULL_TREE, val, result);
2566         }
2567
2568       if (typetail)
2569         typetail = TREE_CHAIN (typetail);
2570     }
2571
2572   if (typetail != 0 && typetail != void_list_node)
2573     {
2574       /* See if there are default arguments that can be used */
2575       if (TREE_PURPOSE (typetail)
2576           && TREE_CODE (TREE_PURPOSE (typetail)) != DEFAULT_ARG)
2577         {
2578           for (; typetail != void_list_node; ++i)
2579             {
2580               tree parmval
2581                 = convert_default_arg (TREE_VALUE (typetail),
2582                                        TREE_PURPOSE (typetail),
2583                                        fndecl, i);
2584
2585               if (parmval == error_mark_node)
2586                 return error_mark_node;
2587
2588               result = tree_cons (0, parmval, result);
2589               typetail = TREE_CHAIN (typetail);
2590               /* ends with `...'.  */
2591               if (typetail == NULL_TREE)
2592                 break;
2593             }
2594         }
2595       else
2596         {
2597           if (fndecl)
2598             {
2599               cp_error_at ("too few arguments to %s `%+#D'",
2600                            called_thing, fndecl);
2601               error ("at this point in file");
2602             }
2603           else
2604             error ("too few arguments to function");
2605           return error_mark_list;
2606         }
2607     }
2608
2609   return nreverse (result);
2610 }
2611 \f
2612 /* Build a binary-operation expression, after performing default
2613    conversions on the operands.  CODE is the kind of expression to build.  */
2614
2615 tree
2616 build_x_binary_op (enum tree_code code, tree arg1, tree arg2)
2617 {
2618   tree orig_arg1;
2619   tree orig_arg2;
2620   tree expr;
2621
2622   orig_arg1 = arg1;
2623   orig_arg2 = arg2;
2624
2625   if (processing_template_decl)
2626     {
2627       if (type_dependent_expression_p (arg1)
2628           || type_dependent_expression_p (arg2))
2629         return build_min_nt (code, arg1, arg2);
2630       arg1 = build_non_dependent_expr (arg1);
2631       arg2 = build_non_dependent_expr (arg2);
2632     }
2633
2634   if (code == DOTSTAR_EXPR)
2635     expr = build_m_component_ref (arg1, arg2);
2636   else
2637     expr = build_new_op (code, LOOKUP_NORMAL, arg1, arg2, NULL_TREE);
2638
2639   if (processing_template_decl && expr != error_mark_node)
2640     return build_min_non_dep (code, expr, orig_arg1, orig_arg2);
2641
2642   return expr;
2643 }
2644
2645 /* Build a binary-operation expression without default conversions.
2646    CODE is the kind of expression to build.
2647    This function differs from `build' in several ways:
2648    the data type of the result is computed and recorded in it,
2649    warnings are generated if arg data types are invalid,
2650    special handling for addition and subtraction of pointers is known,
2651    and some optimization is done (operations on narrow ints
2652    are done in the narrower type when that gives the same result).
2653    Constant folding is also done before the result is returned.
2654
2655    Note that the operands will never have enumeral types
2656    because either they have just had the default conversions performed
2657    or they have both just been converted to some other type in which
2658    the arithmetic is to be done.
2659
2660    C++: must do special pointer arithmetic when implementing
2661    multiple inheritance, and deal with pointer to member functions.  */
2662
2663 tree
2664 build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
2665                  int convert_p ATTRIBUTE_UNUSED)
2666 {
2667   tree op0, op1;
2668   register enum tree_code code0, code1;
2669   tree type0, type1;
2670
2671   /* Expression code to give to the expression when it is built.
2672      Normally this is CODE, which is what the caller asked for,
2673      but in some special cases we change it.  */
2674   register enum tree_code resultcode = code;
2675
2676   /* Data type in which the computation is to be performed.
2677      In the simplest cases this is the common type of the arguments.  */
2678   register tree result_type = NULL;
2679
2680   /* Nonzero means operands have already been type-converted
2681      in whatever way is necessary.
2682      Zero means they need to be converted to RESULT_TYPE.  */
2683   int converted = 0;
2684
2685   /* Nonzero means create the expression with this type, rather than
2686      RESULT_TYPE.  */
2687   tree build_type = 0;
2688
2689   /* Nonzero means after finally constructing the expression
2690      convert it to this type.  */
2691   tree final_type = 0;
2692
2693   /* Nonzero if this is an operation like MIN or MAX which can
2694      safely be computed in short if both args are promoted shorts.
2695      Also implies COMMON.
2696      -1 indicates a bitwise operation; this makes a difference
2697      in the exact conditions for when it is safe to do the operation
2698      in a narrower mode.  */
2699   int shorten = 0;
2700
2701   /* Nonzero if this is a comparison operation;
2702      if both args are promoted shorts, compare the original shorts.
2703      Also implies COMMON.  */
2704   int short_compare = 0;
2705
2706   /* Nonzero if this is a right-shift operation, which can be computed on the
2707      original short and then promoted if the operand is a promoted short.  */
2708   int short_shift = 0;
2709
2710   /* Nonzero means set RESULT_TYPE to the common type of the args.  */
2711   int common = 0;
2712
2713   /* Apply default conversions.  */
2714   op0 = orig_op0;
2715   op1 = orig_op1;
2716
2717   if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
2718       || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
2719       || code == TRUTH_XOR_EXPR)
2720     {
2721       if (!really_overloaded_fn (op0))
2722         op0 = decay_conversion (op0);
2723       if (!really_overloaded_fn (op1))
2724         op1 = decay_conversion (op1);
2725     }
2726   else
2727     {
2728       if (!really_overloaded_fn (op0))
2729         op0 = default_conversion (op0);
2730       if (!really_overloaded_fn (op1))
2731         op1 = default_conversion (op1);
2732     }
2733
2734   /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
2735   STRIP_TYPE_NOPS (op0);
2736   STRIP_TYPE_NOPS (op1);
2737
2738   /* DTRT if one side is an overloaded function, but complain about it.  */
2739   if (type_unknown_p (op0))
2740     {
2741       tree t = instantiate_type (TREE_TYPE (op1), op0, tf_none);
2742       if (t != error_mark_node)
2743         {
2744           pedwarn ("assuming cast to type `%T' from overloaded function",
2745                       TREE_TYPE (t));
2746           op0 = t;
2747         }
2748     }
2749   if (type_unknown_p (op1))
2750     {
2751       tree t = instantiate_type (TREE_TYPE (op0), op1, tf_none);
2752       if (t != error_mark_node)
2753         {
2754           pedwarn ("assuming cast to type `%T' from overloaded function",
2755                       TREE_TYPE (t));
2756           op1 = t;
2757         }
2758     }
2759
2760   type0 = TREE_TYPE (op0);
2761   type1 = TREE_TYPE (op1);
2762
2763   /* The expression codes of the data types of the arguments tell us
2764      whether the arguments are integers, floating, pointers, etc.  */
2765   code0 = TREE_CODE (type0);
2766   code1 = TREE_CODE (type1);
2767
2768   /* If an error was already reported for one of the arguments,
2769      avoid reporting another error.  */
2770
2771   if (code0 == ERROR_MARK || code1 == ERROR_MARK)
2772     return error_mark_node;
2773
2774   switch (code)
2775     {
2776     case PLUS_EXPR:
2777       /* Handle the pointer + int case.  */
2778       if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
2779         return cp_pointer_int_sum (PLUS_EXPR, op0, op1);
2780       else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
2781         return cp_pointer_int_sum (PLUS_EXPR, op1, op0);
2782       else
2783         common = 1;
2784       break;
2785
2786     case MINUS_EXPR:
2787       /* Subtraction of two similar pointers.
2788          We must subtract them as integers, then divide by object size.  */
2789       if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
2790           && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (type0),
2791                                                         TREE_TYPE (type1)))
2792         return pointer_diff (op0, op1, common_type (type0, type1));
2793       /* Handle pointer minus int.  Just like pointer plus int.  */
2794       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
2795         return cp_pointer_int_sum (MINUS_EXPR, op0, op1);
2796       else
2797         common = 1;
2798       break;
2799
2800     case MULT_EXPR:
2801       common = 1;
2802       break;
2803
2804     case TRUNC_DIV_EXPR:
2805     case CEIL_DIV_EXPR:
2806     case FLOOR_DIV_EXPR:
2807     case ROUND_DIV_EXPR:
2808     case EXACT_DIV_EXPR:
2809       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
2810            || code0 == COMPLEX_TYPE)
2811           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
2812               || code1 == COMPLEX_TYPE))
2813         {
2814           if (TREE_CODE (op1) == INTEGER_CST && integer_zerop (op1))
2815             warning ("division by zero in `%E / 0'", op0);
2816           else if (TREE_CODE (op1) == REAL_CST && real_zerop (op1))
2817             warning ("division by zero in `%E / 0.'", op0);
2818
2819           if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
2820             resultcode = RDIV_EXPR;
2821           else
2822             /* When dividing two signed integers, we have to promote to int.
2823                unless we divide by a constant != -1.  Note that default
2824                conversion will have been performed on the operands at this
2825                point, so we have to dig out the original type to find out if
2826                it was unsigned.  */
2827             shorten = ((TREE_CODE (op0) == NOP_EXPR
2828                         && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0))))
2829                        || (TREE_CODE (op1) == INTEGER_CST
2830                            && ! integer_all_onesp (op1)));
2831
2832           common = 1;
2833         }
2834       break;
2835
2836     case BIT_AND_EXPR:
2837     case BIT_IOR_EXPR:
2838     case BIT_XOR_EXPR:
2839       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2840         shorten = -1;
2841       break;
2842
2843     case TRUNC_MOD_EXPR:
2844     case FLOOR_MOD_EXPR:
2845       if (code1 == INTEGER_TYPE && integer_zerop (op1))
2846         warning ("division by zero in `%E %% 0'", op0);
2847       else if (code1 == REAL_TYPE && real_zerop (op1))
2848         warning ("division by zero in `%E %% 0.'", op0);
2849
2850       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2851         {
2852           /* Although it would be tempting to shorten always here, that loses
2853              on some targets, since the modulo instruction is undefined if the
2854              quotient can't be represented in the computation mode.  We shorten
2855              only if unsigned or if dividing by something we know != -1.  */
2856           shorten = ((TREE_CODE (op0) == NOP_EXPR
2857                       && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0))))
2858                      || (TREE_CODE (op1) == INTEGER_CST
2859                          && ! integer_all_onesp (op1)));
2860           common = 1;
2861         }
2862       break;
2863
2864     case TRUTH_ANDIF_EXPR:
2865     case TRUTH_ORIF_EXPR:
2866     case TRUTH_AND_EXPR:
2867     case TRUTH_OR_EXPR:
2868       result_type = boolean_type_node;
2869       break;
2870
2871       /* Shift operations: result has same type as first operand;
2872          always convert second operand to int.
2873          Also set SHORT_SHIFT if shifting rightward.  */
2874
2875     case RSHIFT_EXPR:
2876       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2877         {
2878           result_type = type0;
2879           if (TREE_CODE (op1) == INTEGER_CST)
2880             {
2881               if (tree_int_cst_lt (op1, integer_zero_node))
2882                 warning ("right shift count is negative");
2883               else
2884                 {
2885                   if (! integer_zerop (op1))
2886                     short_shift = 1;
2887                   if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
2888                     warning ("right shift count >= width of type");
2889                 }
2890             }
2891           /* Convert the shift-count to an integer, regardless of
2892              size of value being shifted.  */
2893           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
2894             op1 = cp_convert (integer_type_node, op1);
2895           /* Avoid converting op1 to result_type later.  */
2896           converted = 1;
2897         }
2898       break;
2899
2900     case LSHIFT_EXPR:
2901       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2902         {
2903           result_type = type0;
2904           if (TREE_CODE (op1) == INTEGER_CST)
2905             {
2906               if (tree_int_cst_lt (op1, integer_zero_node))
2907                 warning ("left shift count is negative");
2908               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
2909                 warning ("left shift count >= width of type");
2910             }
2911           /* Convert the shift-count to an integer, regardless of
2912              size of value being shifted.  */
2913           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
2914             op1 = cp_convert (integer_type_node, op1);
2915           /* Avoid converting op1 to result_type later.  */
2916           converted = 1;
2917         }
2918       break;
2919
2920     case RROTATE_EXPR:
2921     case LROTATE_EXPR:
2922       if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
2923         {
2924           result_type = type0;
2925           if (TREE_CODE (op1) == INTEGER_CST)
2926             {
2927               if (tree_int_cst_lt (op1, integer_zero_node))
2928                 warning ("%s rotate count is negative",
2929                          (code == LROTATE_EXPR) ? "left" : "right");
2930               else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
2931                 warning ("%s rotate count >= width of type",
2932                          (code == LROTATE_EXPR) ? "left" : "right");
2933             }
2934           /* Convert the shift-count to an integer, regardless of
2935              size of value being shifted.  */
2936           if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
2937             op1 = cp_convert (integer_type_node, op1);
2938         }
2939       break;
2940
2941     case EQ_EXPR:
2942     case NE_EXPR:
2943       if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
2944         warning ("comparing floating point with == or != is unsafe");
2945
2946       build_type = boolean_type_node;
2947       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
2948            || code0 == COMPLEX_TYPE)
2949           && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
2950               || code1 == COMPLEX_TYPE))
2951         short_compare = 1;
2952       else if ((code0 == POINTER_TYPE && code1 == POINTER_TYPE)
2953                || (TYPE_PTRMEM_P (type0) && TYPE_PTRMEM_P (type1)))
2954         result_type = composite_pointer_type (type0, type1, op0, op1,
2955                                               "comparison");
2956       else if ((code0 == POINTER_TYPE || TYPE_PTRMEM_P (type0))
2957                && null_ptr_cst_p (op1))
2958         result_type = type0;
2959       else if ((code1 == POINTER_TYPE || TYPE_PTRMEM_P (type1))
2960                && null_ptr_cst_p (op0))
2961         result_type = type1;
2962       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
2963         {
2964           result_type = type0;
2965           error ("ISO C++ forbids comparison between pointer and integer");
2966         }
2967       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
2968         {
2969           result_type = type1;
2970           error ("ISO C++ forbids comparison between pointer and integer");
2971         }
2972       else if (TYPE_PTRMEMFUNC_P (type0) && null_ptr_cst_p (op1))
2973         {
2974           op0 = build_ptrmemfunc_access_expr (op0, pfn_identifier);
2975           op1 = cp_convert (TREE_TYPE (op0), integer_zero_node);
2976           result_type = TREE_TYPE (op0);
2977         }
2978       else if (TYPE_PTRMEMFUNC_P (type1) && null_ptr_cst_p (op0))
2979         return cp_build_binary_op (code, op1, op0);
2980       else if (TYPE_PTRMEMFUNC_P (type0) && TYPE_PTRMEMFUNC_P (type1)
2981                && same_type_p (type0, type1))
2982         {
2983           /* E will be the final comparison.  */
2984           tree e;
2985           /* E1 and E2 are for scratch.  */
2986           tree e1;
2987           tree e2;
2988           tree pfn0;
2989           tree pfn1;
2990           tree delta0;
2991           tree delta1;
2992
2993           if (TREE_SIDE_EFFECTS (op0))
2994             op0 = save_expr (op0);
2995           if (TREE_SIDE_EFFECTS (op1))
2996             op1 = save_expr (op1);
2997
2998           /* We generate:
2999
3000              (op0.pfn == op1.pfn
3001               && (!op0.pfn || op0.delta == op1.delta))
3002
3003              The reason for the `!op0.pfn' bit is that a NULL
3004              pointer-to-member is any member with a zero PFN; the
3005              DELTA field is unspecified.  */
3006           pfn0 = pfn_from_ptrmemfunc (op0);
3007           pfn1 = pfn_from_ptrmemfunc (op1);
3008           delta0 = build_ptrmemfunc_access_expr (op0,
3009                                                  delta_identifier);
3010           delta1 = build_ptrmemfunc_access_expr (op1,
3011                                                  delta_identifier);
3012           e1 = cp_build_binary_op (EQ_EXPR, delta0, delta1);
3013           e2 = cp_build_binary_op (EQ_EXPR,
3014                                    pfn0,
3015                                    cp_convert (TREE_TYPE (pfn0),
3016                                                integer_zero_node));
3017           e1 = cp_build_binary_op (TRUTH_ORIF_EXPR, e1, e2);
3018           e2 = build (EQ_EXPR, boolean_type_node, pfn0, pfn1);
3019           e = cp_build_binary_op (TRUTH_ANDIF_EXPR, e2, e1);
3020           if (code == EQ_EXPR)
3021             return e;
3022           return cp_build_binary_op (EQ_EXPR, e, integer_zero_node);
3023         }
3024       else if ((TYPE_PTRMEMFUNC_P (type0)
3025                 && same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type0), type1))
3026                || (TYPE_PTRMEMFUNC_P (type1)
3027                    && same_type_p (TYPE_PTRMEMFUNC_FN_TYPE (type1), type0)))
3028         abort ();
3029       break;
3030
3031     case MAX_EXPR:
3032     case MIN_EXPR:
3033       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
3034            && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
3035         shorten = 1;
3036       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
3037         result_type = composite_pointer_type (type0, type1, op0, op1,
3038                                               "comparison");
3039       break;
3040
3041     case LE_EXPR:
3042     case GE_EXPR:
3043     case LT_EXPR:
3044     case GT_EXPR:
3045       build_type = boolean_type_node;
3046       if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
3047            && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
3048         short_compare = 1;
3049       else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
3050         result_type = composite_pointer_type (type0, type1, op0, op1,
3051                                               "comparison");
3052       else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
3053                && integer_zerop (op1))
3054         result_type = type0;
3055       else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
3056                && integer_zerop (op0))
3057         result_type = type1;
3058       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
3059         {
3060           result_type = type0;
3061           pedwarn ("ISO C++ forbids comparison between pointer and integer");
3062         }
3063       else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
3064         {
3065           result_type = type1;
3066           pedwarn ("ISO C++ forbids comparison between pointer and integer");
3067         }
3068       break;
3069
3070     case UNORDERED_EXPR:
3071     case ORDERED_EXPR:
3072     case UNLT_EXPR:
3073     case UNLE_EXPR:
3074     case UNGT_EXPR:
3075     case UNGE_EXPR:
3076     case UNEQ_EXPR:
3077       build_type = integer_type_node;
3078       if (code0 != REAL_TYPE || code1 != REAL_TYPE)
3079         {
3080           error ("unordered comparison on non-floating point argument");
3081           return error_mark_node;
3082         }
3083       common = 1;
3084       break;
3085
3086     default:
3087       break;
3088     }
3089
3090   if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
3091       &&
3092       (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
3093     {
3094       int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
3095
3096       if (shorten || common || short_compare)
3097         result_type = common_type (type0, type1);
3098
3099       /* For certain operations (which identify themselves by shorten != 0)
3100          if both args were extended from the same smaller type,
3101          do the arithmetic in that type and then extend.
3102
3103          shorten !=0 and !=1 indicates a bitwise operation.
3104          For them, this optimization is safe only if
3105          both args are zero-extended or both are sign-extended.
3106          Otherwise, we might change the result.
3107          Eg, (short)-1 | (unsigned short)-1 is (int)-1
3108          but calculated in (unsigned short) it would be (unsigned short)-1.  */
3109
3110       if (shorten && none_complex)
3111         {
3112           int unsigned0, unsigned1;
3113           tree arg0 = get_narrower (op0, &unsigned0);
3114           tree arg1 = get_narrower (op1, &unsigned1);
3115           /* UNS is 1 if the operation to be done is an unsigned one.  */
3116           int uns = TREE_UNSIGNED (result_type);
3117           tree type;
3118
3119           final_type = result_type;
3120
3121           /* Handle the case that OP0 does not *contain* a conversion
3122              but it *requires* conversion to FINAL_TYPE.  */
3123
3124           if (op0 == arg0 && TREE_TYPE (op0) != final_type)
3125             unsigned0 = TREE_UNSIGNED (TREE_TYPE (op0));
3126           if (op1 == arg1 && TREE_TYPE (op1) != final_type)
3127             unsigned1 = TREE_UNSIGNED (TREE_TYPE (op1));
3128
3129           /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
3130
3131           /* For bitwise operations, signedness of nominal type
3132              does not matter.  Consider only how operands were extended.  */
3133           if (shorten == -1)
3134             uns = unsigned0;
3135
3136           /* Note that in all three cases below we refrain from optimizing
3137              an unsigned operation on sign-extended args.
3138              That would not be valid.  */
3139
3140           /* Both args variable: if both extended in same way
3141              from same width, do it in that width.
3142              Do it unsigned if args were zero-extended.  */
3143           if ((TYPE_PRECISION (TREE_TYPE (arg0))
3144                < TYPE_PRECISION (result_type))
3145               && (TYPE_PRECISION (TREE_TYPE (arg1))
3146                   == TYPE_PRECISION (TREE_TYPE (arg0)))
3147               && unsigned0 == unsigned1
3148               && (unsigned0 || !uns))
3149             result_type = c_common_signed_or_unsigned_type
3150               (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
3151           else if (TREE_CODE (arg0) == INTEGER_CST
3152                    && (unsigned1 || !uns)
3153                    && (TYPE_PRECISION (TREE_TYPE (arg1))
3154                        < TYPE_PRECISION (result_type))
3155                    && (type = c_common_signed_or_unsigned_type
3156                        (unsigned1, TREE_TYPE (arg1)),
3157                        int_fits_type_p (arg0, type)))
3158             result_type = type;
3159           else if (TREE_CODE (arg1) == INTEGER_CST
3160                    && (unsigned0 || !uns)
3161                    && (TYPE_PRECISION (TREE_TYPE (arg0))
3162                        < TYPE_PRECISION (result_type))
3163                    && (type = c_common_signed_or_unsigned_type
3164                        (unsigned0, TREE_TYPE (arg0)),
3165                        int_fits_type_p (arg1, type)))
3166             result_type = type;
3167         }
3168
3169       /* Shifts can be shortened if shifting right.  */
3170
3171       if (short_shift)
3172         {
3173           int unsigned_arg;
3174           tree arg0 = get_narrower (op0, &unsigned_arg);
3175
3176           final_type = result_type;
3177
3178           if (arg0 == op0 && final_type == TREE_TYPE (op0))
3179             unsigned_arg = TREE_UNSIGNED (TREE_TYPE (op0));
3180
3181           if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
3182               /* We can shorten only if the shift count is less than the
3183                  number of bits in the smaller type size.  */
3184               && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
3185               /* If arg is sign-extended and then unsigned-shifted,
3186                  we can simulate this with a signed shift in arg's type
3187                  only if the extended result is at least twice as wide
3188                  as the arg.  Otherwise, the shift could use up all the
3189                  ones made by sign-extension and bring in zeros.
3190                  We can't optimize that case at all, but in most machines
3191                  it never happens because available widths are 2**N.  */
3192               && (!TREE_UNSIGNED (final_type)
3193                   || unsigned_arg
3194                   || (((unsigned) 2 * TYPE_PRECISION (TREE_TYPE (arg0)))
3195                       <= TYPE_PRECISION (result_type))))
3196             {
3197               /* Do an unsigned shift if the operand was zero-extended.  */
3198               result_type
3199                 = c_common_signed_or_unsigned_type (unsigned_arg,
3200                                                     TREE_TYPE (arg0));
3201               /* Convert value-to-be-shifted to that type.  */
3202               if (TREE_TYPE (op0) != result_type)
3203                 op0 = cp_convert (result_type, op0);
3204               converted = 1;
3205             }
3206         }
3207
3208       /* Comparison operations are shortened too but differently.
3209          They identify themselves by setting short_compare = 1.  */
3210
3211       if (short_compare)
3212         {
3213           /* Don't write &op0, etc., because that would prevent op0
3214              from being kept in a register.
3215              Instead, make copies of the our local variables and
3216              pass the copies by reference, then copy them back afterward.  */
3217           tree xop0 = op0, xop1 = op1, xresult_type = result_type;
3218           enum tree_code xresultcode = resultcode;
3219           tree val
3220             = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
3221           if (val != 0)
3222             return cp_convert (boolean_type_node, val);
3223           op0 = xop0, op1 = xop1;
3224           converted = 1;
3225           resultcode = xresultcode;
3226         }
3227
3228       if ((short_compare || code == MIN_EXPR || code == MAX_EXPR)
3229           && warn_sign_compare
3230           /* Do not warn until the template is instantiated; we cannot
3231              bound the ranges of the arguments until that point.  */
3232           && !processing_template_decl)
3233         {
3234           int op0_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op0));
3235           int op1_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op1));
3236
3237           int unsignedp0, unsignedp1;
3238           tree primop0 = get_narrower (op0, &unsignedp0);
3239           tree primop1 = get_narrower (op1, &unsignedp1);
3240
3241           /* Check for comparison of different enum types.  */
3242           if (TREE_CODE (TREE_TYPE (orig_op0)) == ENUMERAL_TYPE
3243               && TREE_CODE (TREE_TYPE (orig_op1)) == ENUMERAL_TYPE
3244               && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0))
3245                  != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1)))
3246             {
3247               warning ("comparison between types `%#T' and `%#T'",
3248                           TREE_TYPE (orig_op0), TREE_TYPE (orig_op1));
3249             }
3250
3251           /* Give warnings for comparisons between signed and unsigned
3252              quantities that may fail.  */
3253           /* Do the checking based on the original operand trees, so that
3254              casts will be considered, but default promotions won't be.  */
3255
3256           /* Do not warn if the comparison is being done in a signed type,
3257              since the signed type will only be chosen if it can represent
3258              all the values of the unsigned type.  */
3259           if (! TREE_UNSIGNED (result_type))
3260             /* OK */;
3261           /* Do not warn if both operands are unsigned.  */
3262           else if (op0_signed == op1_signed)
3263             /* OK */;
3264           /* Do not warn if the signed quantity is an unsuffixed
3265              integer literal (or some static constant expression
3266              involving such literals or a conditional expression
3267              involving such literals) and it is non-negative.  */
3268           else if ((op0_signed && tree_expr_nonnegative_p (orig_op0))
3269                    || (op1_signed && tree_expr_nonnegative_p (orig_op1)))
3270             /* OK */;
3271           /* Do not warn if the comparison is an equality operation,
3272              the unsigned quantity is an integral constant and it does
3273              not use the most significant bit of result_type.  */
3274           else if ((resultcode == EQ_EXPR || resultcode == NE_EXPR)
3275                    && ((op0_signed && TREE_CODE (orig_op1) == INTEGER_CST
3276                         && int_fits_type_p (orig_op1, c_common_signed_type
3277                                             (result_type)))
3278                         || (op1_signed && TREE_CODE (orig_op0) == INTEGER_CST
3279                             && int_fits_type_p (orig_op0, c_common_signed_type
3280                                                 (result_type)))))
3281             /* OK */;
3282           else
3283             warning ("comparison between signed and unsigned integer expressions");
3284
3285           /* Warn if two unsigned values are being compared in a size
3286              larger than their original size, and one (and only one) is the
3287              result of a `~' operator.  This comparison will always fail.
3288
3289              Also warn if one operand is a constant, and the constant does not
3290              have all bits set that are set in the ~ operand when it is
3291              extended.  */
3292
3293           if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
3294               ^ (TREE_CODE (primop1) == BIT_NOT_EXPR))
3295             {
3296               if (TREE_CODE (primop0) == BIT_NOT_EXPR)
3297                 primop0 = get_narrower (TREE_OPERAND (op0, 0), &unsignedp0);
3298               if (TREE_CODE (primop1) == BIT_NOT_EXPR)
3299                 primop1 = get_narrower (TREE_OPERAND (op1, 0), &unsignedp1);
3300
3301               if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
3302                 {
3303                   tree primop;
3304                   HOST_WIDE_INT constant, mask;
3305                   int unsignedp;
3306                   unsigned int bits;
3307
3308                   if (host_integerp (primop0, 0))
3309                     {
3310                       primop = primop1;
3311                       unsignedp = unsignedp1;
3312                       constant = tree_low_cst (primop0, 0);
3313                     }
3314                   else
3315                     {
3316                       primop = primop0;
3317                       unsignedp = unsignedp0;
3318                       constant = tree_low_cst (primop1, 0);
3319                     }
3320
3321                   bits = TYPE_PRECISION (TREE_TYPE (primop));
3322                   if (bits < TYPE_PRECISION (result_type)
3323                       && bits < HOST_BITS_PER_LONG && unsignedp)
3324                     {
3325                       mask = (~ (HOST_WIDE_INT) 0) << bits;
3326                       if ((mask & constant) != mask)
3327                         warning ("comparison of promoted ~unsigned with constant");
3328                     }
3329                 }
3330               else if (unsignedp0 && unsignedp1
3331                        && (TYPE_PRECISION (TREE_TYPE (primop0))
3332                            < TYPE_PRECISION (result_type))
3333                        && (TYPE_PRECISION (TREE_TYPE (primop1))
3334                            < TYPE_PRECISION (result_type)))
3335                 warning ("comparison of promoted ~unsigned with unsigned");
3336             }
3337         }
3338     }
3339
3340   /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
3341      If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
3342      Then the expression will be built.
3343      It will be given type FINAL_TYPE if that is nonzero;
3344      otherwise, it will be given type RESULT_TYPE.  */
3345
3346   if (!result_type)
3347     {
3348       error ("invalid operands of types `%T' and `%T' to binary `%O'",
3349                 TREE_TYPE (orig_op0), TREE_TYPE (orig_op1), code);
3350       return error_mark_node;
3351     }
3352
3353   /* Issue warnings about peculiar, but valid, uses of NULL.  */
3354   if (/* It's reasonable to use pointer values as operands of &&
3355          and ||, so NULL is no exception.  */
3356       !(code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR)
3357       && (/* If OP0 is NULL and OP1 is not a pointer, or vice versa.  */
3358           (orig_op0 == null_node
3359            && TREE_CODE (TREE_TYPE (op1)) != POINTER_TYPE)
3360           /* Or vice versa.  */
3361           || (orig_op1 == null_node
3362               && TREE_CODE (TREE_TYPE (op0)) != POINTER_TYPE)
3363           /* Or, both are NULL and the operation was not a comparison.  */
3364           || (orig_op0 == null_node && orig_op1 == null_node
3365               && code != EQ_EXPR && code != NE_EXPR)))
3366     /* Some sort of arithmetic operation involving NULL was
3367        performed.  Note that pointer-difference and pointer-addition
3368        have already been handled above, and so we don't end up here in
3369        that case.  */
3370     warning ("NULL used in arithmetic");
3371
3372   if (! converted)
3373     {
3374       if (TREE_TYPE (op0) != result_type)
3375         op0 = cp_convert (result_type, op0);
3376       if (TREE_TYPE (op1) != result_type)
3377         op1 = cp_convert (result_type, op1);
3378
3379       if (op0 == error_mark_node || op1 == error_mark_node)
3380         return error_mark_node;
3381     }
3382
3383   if (build_type == NULL_TREE)
3384     build_type = result_type;
3385
3386   {
3387     register tree result = build (resultcode, build_type, op0, op1);
3388     register tree folded;
3389
3390     folded = fold (result);
3391     if (folded == result)
3392       TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
3393     if (final_type != 0)
3394       return cp_convert (final_type, folded);
3395     return folded;
3396   }
3397 }
3398 \f
3399 /* Return a tree for the sum or difference (RESULTCODE says which)
3400    of pointer PTROP and integer INTOP.  */
3401
3402 static tree
3403 cp_pointer_int_sum (enum tree_code resultcode, register tree ptrop,
3404                     register tree intop)
3405 {
3406   tree res_type = TREE_TYPE (ptrop);
3407
3408   /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type)
3409      in certain circumstance (when it's valid to do so).  So we need
3410      to make sure it's complete.  We don't need to check here, if we
3411      can actually complete it at all, as those checks will be done in
3412      pointer_int_sum() anyway.  */
3413   complete_type (TREE_TYPE (res_type));
3414
3415   return pointer_int_sum (resultcode, ptrop, fold (intop));
3416 }
3417
3418 /* Return a tree for the difference of pointers OP0 and OP1.
3419    The resulting tree has type int.  */
3420
3421 static tree
3422 pointer_diff (register tree op0, register tree op1, register tree ptrtype)
3423 {
3424   register tree result, folded;
3425   tree restype = ptrdiff_type_node;
3426   tree target_type = TREE_TYPE (ptrtype);
3427
3428   if (!complete_type_or_else (target_type, NULL_TREE))
3429     return error_mark_node;
3430
3431   if (pedantic || warn_pointer_arith)
3432     {
3433       if (TREE_CODE (target_type) == VOID_TYPE)
3434         pedwarn ("ISO C++ forbids using pointer of type `void *' in subtraction");
3435       if (TREE_CODE (target_type) == FUNCTION_TYPE)
3436         pedwarn ("ISO C++ forbids using pointer to a function in subtraction");
3437       if (TREE_CODE (target_type) == METHOD_TYPE)
3438         pedwarn ("ISO C++ forbids using pointer to a method in subtraction");
3439     }
3440
3441   /* First do the subtraction as integers;
3442      then drop through to build the divide operator.  */
3443
3444   op0 = cp_build_binary_op (MINUS_EXPR,
3445                             cp_convert (restype, op0),
3446                             cp_convert (restype, op1));
3447
3448   /* This generates an error if op1 is a pointer to an incomplete type.  */
3449   if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (op1))))
3450     error ("invalid use of a pointer to an incomplete type in pointer arithmetic");
3451
3452   op1 = (TYPE_PTROB_P (ptrtype)
3453          ? size_in_bytes (target_type)
3454          : integer_one_node);
3455
3456   /* Do the division.  */
3457
3458   result = build (EXACT_DIV_EXPR, restype, op0, cp_convert (restype, op1));
3459
3460   folded = fold (result);
3461   if (folded == result)
3462     TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
3463   return folded;
3464 }
3465 \f
3466 /* Construct and perhaps optimize a tree representation
3467    for a unary operation.  CODE, a tree_code, specifies the operation
3468    and XARG is the operand.  */
3469
3470 tree
3471 build_x_unary_op (enum tree_code code, tree xarg)
3472 {
3473   tree orig_expr = xarg;
3474   tree exp;
3475   int ptrmem = 0;
3476
3477   if (processing_template_decl)
3478     {
3479       if (type_dependent_expression_p (xarg))
3480         return build_min_nt (code, xarg, NULL_TREE);
3481       xarg = build_non_dependent_expr (xarg);
3482     }
3483
3484   exp = NULL_TREE;
3485
3486   /* & rec, on incomplete RECORD_TYPEs is the simple opr &, not an
3487      error message.  */
3488   if (code == ADDR_EXPR
3489       && TREE_CODE (xarg) != TEMPLATE_ID_EXPR
3490       && ((IS_AGGR_TYPE_CODE (TREE_CODE (TREE_TYPE (xarg)))
3491            && !COMPLETE_TYPE_P (TREE_TYPE (xarg)))
3492           || (TREE_CODE (xarg) == OFFSET_REF)))
3493     /* don't look for a function */;
3494   else
3495     exp = build_new_op (code, LOOKUP_NORMAL, xarg, NULL_TREE, NULL_TREE);
3496   if (!exp && code == ADDR_EXPR)
3497     {
3498       /*  A pointer to member-function can be formed only by saying
3499           &X::mf.  */
3500       if (!flag_ms_extensions && TREE_CODE (TREE_TYPE (xarg)) == METHOD_TYPE
3501           && (TREE_CODE (xarg) != OFFSET_REF || !PTRMEM_OK_P (xarg)))
3502         {
3503           if (TREE_CODE (xarg) != OFFSET_REF)
3504             {
3505               error ("invalid use of '%E' to form a pointer-to-member-function.  Use a qualified-id.",
3506                      xarg);
3507               return error_mark_node;
3508             }
3509           else
3510             {
3511               error ("parenthesis around '%E' cannot be used to form a pointer-to-member-function",
3512                      xarg);
3513               PTRMEM_OK_P (xarg) = 1;
3514             }
3515         }
3516
3517       if (TREE_CODE (xarg) == OFFSET_REF)
3518         {
3519           ptrmem = PTRMEM_OK_P (xarg);
3520
3521           if (!ptrmem && !flag_ms_extensions
3522               && TREE_CODE (TREE_TYPE (TREE_OPERAND (xarg, 1))) == METHOD_TYPE)
3523             {
3524               /* A single non-static member, make sure we don't allow a
3525                  pointer-to-member.  */
3526               xarg = build (OFFSET_REF, TREE_TYPE (xarg),
3527                             TREE_OPERAND (xarg, 0),
3528                             ovl_cons (TREE_OPERAND (xarg, 1), NULL_TREE));
3529               PTRMEM_OK_P (xarg) = ptrmem;
3530             }
3531         }
3532       else if (TREE_CODE (xarg) == TARGET_EXPR)
3533         warning ("taking address of temporary");
3534       exp = build_unary_op (ADDR_EXPR, xarg, 0);
3535       if (TREE_CODE (exp) == ADDR_EXPR)
3536         PTRMEM_OK_P (exp) = ptrmem;
3537     }
3538
3539   if (processing_template_decl && exp != error_mark_node)
3540     return build_min_non_dep (code, exp, orig_expr,
3541                               /*For {PRE,POST}{INC,DEC}REMENT_EXPR*/NULL_TREE);
3542   return exp;
3543 }
3544
3545 /* Like c_common_truthvalue_conversion, but handle pointer-to-member
3546    constants, where a null value is represented by an INTEGER_CST of
3547    -1.  */
3548
3549 tree
3550 cp_truthvalue_conversion (tree expr)
3551 {
3552   tree type = TREE_TYPE (expr);
3553   if (TYPE_PTRMEM_P (type))
3554     return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
3555   else
3556     return c_common_truthvalue_conversion (expr);
3557 }
3558
3559 /* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR.  */
3560
3561 tree
3562 condition_conversion (tree expr)
3563 {
3564   tree t;
3565   if (processing_template_decl)
3566     return expr;
3567   t = perform_implicit_conversion (boolean_type_node, expr);
3568   t = fold (build1 (CLEANUP_POINT_EXPR, boolean_type_node, t));
3569   return t;
3570 }
3571
3572 /* Return an ADDR_EXPR giving the address of T.  This function
3573    attempts no optimizations or simplifications; it is a low-level
3574    primitive.  */
3575
3576 tree
3577 build_address (tree t)
3578 {
3579   tree addr;
3580
3581   if (error_operand_p (t) || !cxx_mark_addressable (t))
3582     return error_mark_node;
3583
3584   addr = build1 (ADDR_EXPR,
3585                  build_pointer_type (TREE_TYPE (t)),
3586                  t);
3587   if (staticp (t))
3588     TREE_CONSTANT (addr) = 1;
3589
3590   return addr;
3591 }
3592
3593 /* Return a NOP_EXPR converting EXPR to TYPE.  */
3594
3595 tree
3596 build_nop (tree type, tree expr)
3597 {
3598   tree nop;
3599
3600   if (type == error_mark_node || error_operand_p (expr))
3601     return expr;
3602
3603   nop = build1 (NOP_EXPR, type, expr);
3604   if (TREE_CONSTANT (expr))
3605     TREE_CONSTANT (nop) = 1;
3606
3607   return nop;
3608 }
3609
3610 /* C++: Must handle pointers to members.
3611
3612    Perhaps type instantiation should be extended to handle conversion
3613    from aggregates to types we don't yet know we want?  (Or are those
3614    cases typically errors which should be reported?)
3615
3616    NOCONVERT nonzero suppresses the default promotions
3617    (such as from short to int).  */
3618
3619 tree
3620 build_unary_op (enum tree_code code, tree xarg, int noconvert)
3621 {
3622   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3623   register tree arg = xarg;
3624   register tree argtype = 0;
3625   const char *errstring = NULL;
3626   tree val;
3627
3628   if (arg == error_mark_node)
3629     return error_mark_node;
3630
3631   switch (code)
3632     {
3633     case CONVERT_EXPR:
3634       /* This is used for unary plus, because a CONVERT_EXPR
3635          is enough to prevent anybody from looking inside for
3636          associativity, but won't generate any code.  */
3637       if (!(arg = build_expr_type_conversion
3638             (WANT_ARITH | WANT_ENUM | WANT_POINTER, arg, true)))
3639         errstring = "wrong type argument to unary plus";
3640       else
3641         {
3642           if (!noconvert)
3643            arg = default_conversion (arg);
3644           arg = build1 (NON_LVALUE_EXPR, TREE_TYPE (arg), arg);
3645           TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3646         }
3647       break;
3648
3649     case NEGATE_EXPR:
3650       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3651         errstring = "wrong type argument to unary minus";
3652       else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg)))
3653         arg = perform_integral_promotions (arg);
3654       break;
3655
3656     case BIT_NOT_EXPR:
3657       if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3658         {
3659           code = CONJ_EXPR;
3660           if (!noconvert)
3661             arg = default_conversion (arg);
3662         }
3663       else if (!(arg = build_expr_type_conversion (WANT_INT | WANT_ENUM,
3664                                                    arg, true)))
3665         errstring = "wrong type argument to bit-complement";
3666       else if (!noconvert)
3667         arg = perform_integral_promotions (arg);
3668       break;
3669
3670     case ABS_EXPR:
3671       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3672         errstring = "wrong type argument to abs";
3673       else if (!noconvert)
3674         arg = default_conversion (arg);
3675       break;
3676
3677     case CONJ_EXPR:
3678       /* Conjugating a real value is a no-op, but allow it anyway.  */
3679       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3680         errstring = "wrong type argument to conjugation";
3681       else if (!noconvert)
3682         arg = default_conversion (arg);
3683       break;
3684
3685     case TRUTH_NOT_EXPR:
3686       arg = perform_implicit_conversion (boolean_type_node, arg);
3687       val = invert_truthvalue (arg);
3688       if (arg != error_mark_node)
3689         return val;
3690       errstring = "in argument to unary !";
3691       break;
3692
3693     case NOP_EXPR:
3694       break;
3695
3696     case REALPART_EXPR:
3697       if (TREE_CODE (arg) == COMPLEX_CST)
3698         return TREE_REALPART (arg);
3699       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3700         return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
3701       else
3702         return arg;
3703
3704     case IMAGPART_EXPR:
3705       if (TREE_CODE (arg) == COMPLEX_CST)
3706         return TREE_IMAGPART (arg);
3707       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3708         return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
3709       else
3710         return cp_convert (TREE_TYPE (arg), integer_zero_node);
3711
3712     case PREINCREMENT_EXPR:
3713     case POSTINCREMENT_EXPR:
3714     case PREDECREMENT_EXPR:
3715     case POSTDECREMENT_EXPR:
3716       /* Handle complex lvalues (when permitted)
3717          by reduction to simpler cases.  */
3718
3719       val = unary_complex_lvalue (code, arg);
3720       if (val != 0)
3721         return val;
3722
3723       /* Increment or decrement the real part of the value,
3724          and don't change the imaginary part.  */
3725       if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3726         {
3727           tree real, imag;
3728
3729           arg = stabilize_reference (arg);
3730           real = build_unary_op (REALPART_EXPR, arg, 1);
3731           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3732           return build (COMPLEX_EXPR, TREE_TYPE (arg),
3733                         build_unary_op (code, real, 1), imag);
3734         }
3735
3736       /* Report invalid types.  */
3737
3738       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_POINTER,
3739                                               arg, true)))
3740         {
3741           if (code == PREINCREMENT_EXPR)
3742             errstring ="no pre-increment operator for type";
3743           else if (code == POSTINCREMENT_EXPR)
3744             errstring ="no post-increment operator for type";
3745           else if (code == PREDECREMENT_EXPR)
3746             errstring ="no pre-decrement operator for type";
3747           else
3748             errstring ="no post-decrement operator for type";
3749           break;
3750         }
3751
3752       /* Report something read-only.  */
3753
3754       if (CP_TYPE_CONST_P (TREE_TYPE (arg))
3755           || TREE_READONLY (arg))
3756         readonly_error (arg, ((code == PREINCREMENT_EXPR
3757                                || code == POSTINCREMENT_EXPR)
3758                               ? "increment" : "decrement"),
3759                         0);
3760
3761       {
3762         register tree inc;
3763         tree result_type = TREE_TYPE (arg);
3764
3765         arg = get_unwidened (arg, 0);
3766         argtype = TREE_TYPE (arg);
3767
3768         /* ARM $5.2.5 last annotation says this should be forbidden.  */
3769         if (TREE_CODE (argtype) == ENUMERAL_TYPE)
3770           pedwarn ("ISO C++ forbids %sing an enum",
3771                    (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3772                    ? "increment" : "decrement");
3773
3774         /* Compute the increment.  */
3775
3776         if (TREE_CODE (argtype) == POINTER_TYPE)
3777           {
3778             tree type = complete_type (TREE_TYPE (argtype));
3779
3780             if (!COMPLETE_OR_VOID_TYPE_P (type))
3781               error ("cannot %s a pointer to incomplete type `%T'",
3782                         ((code == PREINCREMENT_EXPR
3783                           || code == POSTINCREMENT_EXPR)
3784                          ? "increment" : "decrement"), TREE_TYPE (argtype));
3785             else if ((pedantic || warn_pointer_arith)
3786                      && !TYPE_PTROB_P (argtype))
3787               pedwarn ("ISO C++ forbids %sing a pointer of type `%T'",
3788                           ((code == PREINCREMENT_EXPR
3789                             || code == POSTINCREMENT_EXPR)
3790                            ? "increment" : "decrement"), argtype);
3791             inc = cxx_sizeof_nowarn (TREE_TYPE (argtype));
3792           }
3793         else
3794           inc = integer_one_node;
3795
3796         inc = cp_convert (argtype, inc);
3797
3798         /* Handle incrementing a cast-expression.  */
3799
3800         switch (TREE_CODE (arg))
3801           {
3802           case NOP_EXPR:
3803           case CONVERT_EXPR:
3804           case FLOAT_EXPR:
3805           case FIX_TRUNC_EXPR:
3806           case FIX_FLOOR_EXPR:
3807           case FIX_ROUND_EXPR:
3808           case FIX_CEIL_EXPR:
3809             {
3810               tree incremented, modify, value, compound;
3811               if (! lvalue_p (arg) && pedantic)
3812                 pedwarn ("cast to non-reference type used as lvalue");
3813               arg = stabilize_reference (arg);
3814               if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR)
3815                 value = arg;
3816               else
3817                 value = save_expr (arg);
3818               incremented = build (((code == PREINCREMENT_EXPR
3819                                      || code == POSTINCREMENT_EXPR)
3820                                     ? PLUS_EXPR : MINUS_EXPR),
3821                                    argtype, value, inc);
3822
3823               modify = build_modify_expr (arg, NOP_EXPR, incremented);
3824               compound = build (COMPOUND_EXPR, TREE_TYPE (arg), modify, value);
3825
3826               /* Eliminate warning about unused result of + or -.  */
3827               TREE_NO_UNUSED_WARNING (compound) = 1;
3828               return compound;
3829             }
3830
3831           default:
3832             break;
3833           }
3834
3835         /* Complain about anything else that is not a true lvalue.  */
3836         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3837                                     || code == POSTINCREMENT_EXPR)
3838                                    ? "increment" : "decrement")))
3839           return error_mark_node;
3840
3841         /* Forbid using -- on `bool'.  */
3842         if (TREE_TYPE (arg) == boolean_type_node)
3843           {
3844             if (code == POSTDECREMENT_EXPR || code == PREDECREMENT_EXPR)
3845               {
3846                 error ("invalid use of `--' on bool variable `%D'", arg);
3847                 return error_mark_node;
3848               }
3849             val = boolean_increment (code, arg);
3850           }
3851         else
3852           val = build (code, TREE_TYPE (arg), arg, inc);
3853
3854         TREE_SIDE_EFFECTS (val) = 1;
3855         return cp_convert (result_type, val);
3856       }
3857
3858     case ADDR_EXPR:
3859       /* Note that this operation never does default_conversion
3860          regardless of NOCONVERT.  */
3861
3862       argtype = lvalue_type (arg);
3863
3864       if (TREE_CODE (arg) == OFFSET_REF)
3865         goto offset_ref;
3866
3867       if (TREE_CODE (argtype) == REFERENCE_TYPE)
3868         {
3869           arg = build1
3870             (CONVERT_EXPR,
3871              build_pointer_type (TREE_TYPE (argtype)), arg);
3872           TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3873           return arg;
3874         }
3875       else if (pedantic && DECL_MAIN_P (arg))
3876         /* ARM $3.4 */
3877         pedwarn ("ISO C++ forbids taking address of function `::main'");
3878
3879       /* Let &* cancel out to simplify resulting code.  */
3880       if (TREE_CODE (arg) == INDIRECT_REF)
3881         {
3882           /* We don't need to have `current_class_ptr' wrapped in a
3883              NON_LVALUE_EXPR node.  */
3884           if (arg == current_class_ref)
3885             return current_class_ptr;
3886
3887           arg = TREE_OPERAND (arg, 0);
3888           if (TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE)
3889             {
3890               arg = build1
3891                 (CONVERT_EXPR,
3892                  build_pointer_type (TREE_TYPE (TREE_TYPE (arg))), arg);
3893               TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3894             }
3895           else if (lvalue_p (arg))
3896             /* Don't let this be an lvalue.  */
3897             return non_lvalue (arg);
3898           return arg;
3899         }
3900
3901       /* For &x[y], return x+y */
3902       if (TREE_CODE (arg) == ARRAY_REF)
3903         {
3904           if (!cxx_mark_addressable (TREE_OPERAND (arg, 0)))
3905             return error_mark_node;
3906           return cp_build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
3907                                      TREE_OPERAND (arg, 1));
3908         }
3909
3910       /* Uninstantiated types are all functions.  Taking the
3911          address of a function is a no-op, so just return the
3912          argument.  */
3913
3914       if (TREE_CODE (arg) == IDENTIFIER_NODE
3915           && IDENTIFIER_OPNAME_P (arg))
3916         {
3917           abort ();
3918           /* We don't know the type yet, so just work around the problem.
3919              We know that this will resolve to an lvalue.  */
3920           return build1 (ADDR_EXPR, unknown_type_node, arg);
3921         }
3922
3923       if (TREE_CODE (arg) == COMPONENT_REF && type_unknown_p (arg)
3924           && !really_overloaded_fn (TREE_OPERAND (arg, 1)))
3925         {
3926           /* They're trying to take the address of a unique non-static
3927              member function.  This is ill-formed (except in MS-land),
3928              but let's try to DTRT.
3929              Note: We only handle unique functions here because we don't
3930              want to complain if there's a static overload; non-unique
3931              cases will be handled by instantiate_type.  But we need to
3932              handle this case here to allow casts on the resulting PMF.
3933              We could defer this in non-MS mode, but it's easier to give
3934              a useful error here.  */
3935
3936           /* Inside constant member functions, the `this' pointer
3937              contains an extra const qualifier.  TYPE_MAIN_VARIANT
3938              is used here to remove this const from the diagnostics
3939              and the created OFFSET_REF.  */
3940           tree base = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (arg, 0)));
3941           tree name = DECL_NAME (get_first_fn (TREE_OPERAND (arg, 1)));
3942
3943           if (! flag_ms_extensions)
3944             {
3945               if (current_class_type
3946                   && TREE_OPERAND (arg, 0) == current_class_ref)
3947                 /* An expression like &memfn.  */
3948                 pedwarn ("ISO C++ forbids taking the address of an unqualified"
3949                          " or parenthesized non-static member function to form"
3950                          " a pointer to member function.  Say `&%T::%D'",
3951                          base, name);
3952               else
3953                 pedwarn ("ISO C++ forbids taking the address of a bound member"
3954                          " function to form a pointer to member function."
3955                          "  Say `&%T::%D'",
3956                          base, name);
3957             }
3958           arg = build_offset_ref (base, name, /*address_p=*/true);
3959         }
3960
3961     offset_ref:
3962       if (type_unknown_p (arg))
3963         return build1 (ADDR_EXPR, unknown_type_node, arg);
3964
3965       /* Handle complex lvalues (when permitted)
3966          by reduction to simpler cases.  */
3967       val = unary_complex_lvalue (code, arg);
3968       if (val != 0)
3969         return val;
3970
3971       switch (TREE_CODE (arg))
3972         {
3973         case NOP_EXPR:
3974         case CONVERT_EXPR:
3975         case FLOAT_EXPR:
3976         case FIX_TRUNC_EXPR:
3977         case FIX_FLOOR_EXPR:
3978         case FIX_ROUND_EXPR:
3979         case FIX_CEIL_EXPR:
3980           if (! lvalue_p (arg) && pedantic)
3981             pedwarn ("ISO C++ forbids taking the address of a cast to a non-lvalue expression");
3982           break;
3983
3984         default:
3985           break;
3986         }
3987
3988       /* Allow the address of a constructor if all the elements
3989          are constant.  */
3990       if (TREE_CODE (arg) == CONSTRUCTOR && TREE_HAS_CONSTRUCTOR (arg)
3991           && TREE_CONSTANT (arg))
3992         ;
3993       /* Anything not already handled and not a true memory reference
3994          is an error.  */
3995       else if (TREE_CODE (argtype) != FUNCTION_TYPE
3996                && TREE_CODE (argtype) != METHOD_TYPE
3997                && !lvalue_or_else (arg, "unary `&'"))
3998         return error_mark_node;
3999
4000       if (argtype != error_mark_node)
4001         argtype = build_pointer_type (argtype);
4002
4003       {
4004         tree addr;
4005
4006         if (TREE_CODE (arg) == COMPONENT_REF
4007             && TREE_CODE (TREE_OPERAND (arg, 1)) == BASELINK)
4008           arg = BASELINK_FUNCTIONS (TREE_OPERAND (arg, 1));
4009
4010         if (TREE_CODE (arg) != COMPONENT_REF)
4011           addr = build_address (arg);
4012         else if (DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)))
4013           {
4014             error ("attempt to take address of bit-field structure member `%D'",
4015                    TREE_OPERAND (arg, 1));
4016             return error_mark_node;
4017           }
4018         else
4019           {
4020             /* Unfortunately we cannot just build an address
4021                expression here, because we would not handle
4022                address-constant-expressions or offsetof correctly.  */
4023             tree field = TREE_OPERAND (arg, 1);
4024             tree rval = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), 0);
4025             tree binfo = lookup_base (TREE_TYPE (TREE_TYPE (rval)),
4026                                       decl_type_context (field),
4027                                       ba_check, NULL);
4028
4029             rval = build_base_path (PLUS_EXPR, rval, binfo, 1);
4030             rval = build_nop (argtype, rval);
4031             addr = fold (build (PLUS_EXPR, argtype, rval,
4032                                 cp_convert (argtype, byte_position (field))));
4033           }
4034
4035         if (TREE_CODE (argtype) == POINTER_TYPE
4036             && TREE_CODE (TREE_TYPE (argtype)) == METHOD_TYPE)
4037           {
4038             build_ptrmemfunc_type (argtype);
4039             addr = build_ptrmemfunc (argtype, addr, 0);
4040           }
4041
4042         return addr;
4043       }
4044
4045     default:
4046       break;
4047     }
4048
4049   if (!errstring)
4050     {
4051       if (argtype == 0)
4052         argtype = TREE_TYPE (arg);
4053       return fold (build1 (code, argtype, arg));
4054     }
4055
4056   error ("%s", errstring);
4057   return error_mark_node;
4058 }
4059
4060 /* Apply unary lvalue-demanding operator CODE to the expression ARG
4061    for certain kinds of expressions which are not really lvalues
4062    but which we can accept as lvalues.
4063
4064    If ARG is not a kind of expression we can handle, return zero.  */
4065
4066 tree
4067 unary_complex_lvalue (enum tree_code code, tree arg)
4068 {
4069   /* Handle (a, b) used as an "lvalue".  */
4070   if (TREE_CODE (arg) == COMPOUND_EXPR)
4071     {
4072       tree real_result = build_unary_op (code, TREE_OPERAND (arg, 1), 0);
4073       return build (COMPOUND_EXPR, TREE_TYPE (real_result),
4074                     TREE_OPERAND (arg, 0), real_result);
4075     }
4076
4077   /* Handle (a ? b : c) used as an "lvalue".  */
4078   if (TREE_CODE (arg) == COND_EXPR
4079       || TREE_CODE (arg) == MIN_EXPR || TREE_CODE (arg) == MAX_EXPR)
4080     return rationalize_conditional_expr (code, arg);
4081
4082   /* Handle (a = b), (++a), and (--a) used as an "lvalue".  */
4083   if (TREE_CODE (arg) == MODIFY_EXPR
4084       || TREE_CODE (arg) == PREINCREMENT_EXPR
4085       || TREE_CODE (arg) == PREDECREMENT_EXPR)
4086     {
4087       tree lvalue = TREE_OPERAND (arg, 0);
4088       if (TREE_SIDE_EFFECTS (lvalue))
4089         {
4090           lvalue = stabilize_reference (lvalue);
4091           arg = build (TREE_CODE (arg), TREE_TYPE (arg),
4092                        lvalue, TREE_OPERAND (arg, 1));
4093         }
4094       return unary_complex_lvalue
4095         (code, build (COMPOUND_EXPR, TREE_TYPE (lvalue), arg, lvalue));
4096     }
4097
4098   if (code != ADDR_EXPR)
4099     return 0;
4100
4101   /* Handle (a = b) used as an "lvalue" for `&'.  */
4102   if (TREE_CODE (arg) == MODIFY_EXPR
4103       || TREE_CODE (arg) == INIT_EXPR)
4104     {
4105       tree real_result = build_unary_op (code, TREE_OPERAND (arg, 0), 0);
4106       arg = build (COMPOUND_EXPR, TREE_TYPE (real_result), arg, real_result);
4107       TREE_NO_UNUSED_WARNING (arg) = 1;
4108       return arg;
4109     }
4110
4111   if (TREE_CODE (TREE_TYPE (arg)) == FUNCTION_TYPE
4112       || TREE_CODE (TREE_TYPE (arg)) == METHOD_TYPE
4113       || TREE_CODE (arg) == OFFSET_REF)
4114     {
4115       tree t;
4116
4117       my_friendly_assert (TREE_CODE (arg) != SCOPE_REF, 313);
4118
4119       if (TREE_CODE (arg) != OFFSET_REF)
4120         return 0;
4121
4122       t = TREE_OPERAND (arg, 1);
4123
4124       /* Check all this code for right semantics.  */
4125       if (TREE_CODE (t) == FUNCTION_DECL)
4126         {
4127           if (DECL_DESTRUCTOR_P (t))
4128             error ("taking address of destructor");
4129           return build_unary_op (ADDR_EXPR, t, 0);
4130         }
4131       if (TREE_CODE (t) == VAR_DECL)
4132         return build_unary_op (ADDR_EXPR, t, 0);
4133       else
4134         {
4135           tree type;
4136
4137           if (TREE_OPERAND (arg, 0)
4138               && ! is_dummy_object (TREE_OPERAND (arg, 0))
4139               && TREE_CODE (t) != FIELD_DECL)
4140             {
4141               error ("taking address of bound pointer-to-member expression");
4142               return error_mark_node;
4143             }
4144           if (!PTRMEM_OK_P (arg))
4145             return build_unary_op (code, arg, 0);
4146
4147           if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE)
4148             {
4149               error ("cannot create pointer to reference member `%D'", t);
4150               return error_mark_node;
4151             }
4152
4153           type = build_ptrmem_type (DECL_FIELD_CONTEXT (t), TREE_TYPE (t));
4154           t = make_ptrmem_cst (type, TREE_OPERAND (arg, 1));
4155           return t;
4156         }
4157     }
4158
4159
4160   /* We permit compiler to make function calls returning
4161      objects of aggregate type look like lvalues.  */
4162   {
4163     tree targ = arg;
4164
4165     if (TREE_CODE (targ) == SAVE_EXPR)
4166       targ = TREE_OPERAND (targ, 0);
4167
4168     if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (TREE_TYPE (targ)))
4169       {
4170         if (TREE_CODE (arg) == SAVE_EXPR)
4171           targ = arg;
4172         else
4173           targ = build_cplus_new (TREE_TYPE (arg), arg);
4174         return build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (arg)), targ);
4175       }
4176
4177     if (TREE_CODE (arg) == SAVE_EXPR && TREE_CODE (targ) == INDIRECT_REF)
4178       return build (SAVE_EXPR, build_pointer_type (TREE_TYPE (arg)),
4179                      TREE_OPERAND (targ, 0), current_function_decl, NULL);
4180   }
4181
4182   /* Don't let anything else be handled specially.  */
4183   return 0;
4184 }
4185 \f
4186 /* Mark EXP saying that we need to be able to take the
4187    address of it; it should not be allocated in a register.
4188    Value is true if successful.
4189
4190    C++: we do not allow `current_class_ptr' to be addressable.  */
4191
4192 bool
4193 cxx_mark_addressable (tree exp)
4194 {
4195   register tree x = exp;
4196
4197   while (1)
4198     switch (TREE_CODE (x))
4199       {
4200       case ADDR_EXPR:
4201       case COMPONENT_REF:
4202       case ARRAY_REF:
4203       case REALPART_EXPR:
4204       case IMAGPART_EXPR:
4205         x = TREE_OPERAND (x, 0);
4206         break;
4207
4208       case PARM_DECL:
4209         if (x == current_class_ptr)
4210           {
4211             error ("cannot take the address of `this', which is an rvalue expression");
4212             TREE_ADDRESSABLE (x) = 1; /* so compiler doesn't die later */
4213             return true;
4214           }
4215         /* FALLTHRU */
4216
4217       case VAR_DECL:
4218         /* Caller should not be trying to mark initialized
4219            constant fields addressable.  */
4220         my_friendly_assert (DECL_LANG_SPECIFIC (x) == 0
4221                             || DECL_IN_AGGR_P (x) == 0
4222                             || TREE_STATIC (x)
4223                             || DECL_EXTERNAL (x), 314);
4224         /* FALLTHRU */
4225
4226       case CONST_DECL:
4227       case RESULT_DECL:
4228         if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x)
4229             && !DECL_ARTIFICIAL (x) && extra_warnings)
4230           warning ("address requested for `%D', which is declared `register'",
4231                       x);
4232         TREE_ADDRESSABLE (x) = 1;
4233         put_var_into_stack (x, /*rescan=*/true);
4234         return true;
4235
4236       case FUNCTION_DECL:
4237         TREE_ADDRESSABLE (x) = 1;
4238         TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (x)) = 1;
4239         return true;
4240
4241       case CONSTRUCTOR:
4242         TREE_ADDRESSABLE (x) = 1;
4243         return true;
4244
4245       case TARGET_EXPR:
4246         TREE_ADDRESSABLE (x) = 1;
4247         cxx_mark_addressable (TREE_OPERAND (x, 0));
4248         return true;
4249
4250       default:
4251         return true;
4252     }
4253 }
4254 \f
4255 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
4256
4257 tree
4258 build_x_conditional_expr (tree ifexp, tree op1, tree op2)
4259 {
4260   tree orig_ifexp = ifexp;
4261   tree orig_op1 = op1;
4262   tree orig_op2 = op2;
4263   tree expr;
4264
4265   if (processing_template_decl)
4266     {
4267       /* The standard says that the expression is type-dependent if
4268          IFEXP is type-dependent, even though the eventual type of the
4269          expression doesn't dependent on IFEXP.  */
4270       if (type_dependent_expression_p (ifexp)
4271           || type_dependent_expression_p (op1)
4272           || type_dependent_expression_p (op2))
4273         return build_min_nt (COND_EXPR, ifexp, op1, op2);
4274       ifexp = build_non_dependent_expr (ifexp);
4275       op1 = build_non_dependent_expr (op1);
4276       op2 = build_non_dependent_expr (op2);
4277     }
4278
4279   expr = build_conditional_expr (ifexp, op1, op2);
4280   if (processing_template_decl && expr != error_mark_node)
4281     return build_min_non_dep (COND_EXPR, expr,
4282                               orig_ifexp, orig_op1, orig_op2);
4283   return expr;
4284 }
4285 \f
4286 /* Given a list of expressions, return a compound expression
4287    that performs them all and returns the value of the last of them. */
4288
4289 tree build_x_compound_expr_from_list (tree list, const char *msg)
4290 {
4291   tree expr = TREE_VALUE (list);
4292
4293   if (TREE_CHAIN (list))
4294     {
4295       if (msg)
4296         pedwarn ("%s expression list treated as compound expression", msg);
4297
4298       for (list = TREE_CHAIN (list); list; list = TREE_CHAIN (list))
4299         expr = build_x_compound_expr (expr, TREE_VALUE (list));
4300     }
4301
4302   return expr;
4303 }
4304
4305 /* Handle overloading of the ',' operator when needed.  */
4306
4307 tree
4308 build_x_compound_expr (tree op1, tree op2)
4309 {
4310   tree result;
4311   tree orig_op1 = op1;
4312   tree orig_op2 = op2;
4313
4314   if (processing_template_decl)
4315     {
4316       if (type_dependent_expression_p (op1)
4317           || type_dependent_expression_p (op2))
4318         return build_min_nt (COMPOUND_EXPR, op1, op2);
4319       op1 = build_non_dependent_expr (op1);
4320       op2 = build_non_dependent_expr (op2);
4321     }
4322
4323   result = build_new_op (COMPOUND_EXPR, LOOKUP_NORMAL, op1, op2, NULL_TREE);
4324   if (!result)
4325     result = build_compound_expr (op1, op2);
4326
4327   if (processing_template_decl && result != error_mark_node)
4328     return build_min_non_dep (COMPOUND_EXPR, result, orig_op1, orig_op2);
4329
4330   return result;
4331 }
4332
4333 /* Build a compound expression. */
4334
4335 tree
4336 build_compound_expr (tree lhs, tree rhs)
4337 {
4338   lhs = decl_constant_value (lhs);
4339   lhs = convert_to_void (lhs, "left-hand operand of comma");
4340
4341   if (lhs == error_mark_node || rhs == error_mark_node)
4342     return error_mark_node;
4343
4344   if (TREE_CODE (rhs) == TARGET_EXPR)
4345     {
4346       /* If the rhs is a TARGET_EXPR, then build the compound
4347          expression inside the target_expr's initializer. This
4348          helps the compiler to eliminate unncessary temporaries.  */
4349       tree init = TREE_OPERAND (rhs, 1);
4350
4351       init = build (COMPOUND_EXPR, TREE_TYPE (init), lhs, init);
4352       TREE_OPERAND (rhs, 1) = init;
4353
4354       return rhs;
4355     }
4356
4357   return build (COMPOUND_EXPR, TREE_TYPE (rhs), lhs, rhs);
4358 }
4359
4360 /* Issue an error message if casting from SRC_TYPE to DEST_TYPE casts
4361    away constness.  DESCRIPTION explains what operation is taking
4362    place.  */
4363
4364 static void
4365 check_for_casting_away_constness (tree src_type, tree dest_type,
4366                                   const char *description)
4367 {
4368   if (casts_away_constness (src_type, dest_type))
4369     error ("%s from type `%T' to type `%T' casts away constness",
4370            description, src_type, dest_type);
4371 }
4372
4373 /* Return an expression representing static_cast<TYPE>(EXPR).  */
4374
4375 tree
4376 build_static_cast (tree type, tree expr)
4377 {
4378   tree intype;
4379   tree result;
4380
4381   if (type == error_mark_node || expr == error_mark_node)
4382     return error_mark_node;
4383
4384   if (processing_template_decl)
4385     {
4386       expr = build_min (STATIC_CAST_EXPR, type, expr);
4387       /* We don't know if it will or will not have side effects.  */
4388       TREE_SIDE_EFFECTS (expr) = 1;
4389       return expr;
4390     }
4391
4392   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4393      Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4394   if (TREE_CODE (type) != REFERENCE_TYPE
4395       && TREE_CODE (expr) == NOP_EXPR
4396       && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4397     expr = TREE_OPERAND (expr, 0);
4398
4399   intype = TREE_TYPE (expr);
4400
4401   /* [expr.static.cast]
4402
4403      An lvalue of type "cv1 B", where B is a class type, can be cast
4404      to type "reference to cv2 D", where D is a class derived (clause
4405      _class.derived_) from B, if a valid standard conversion from
4406      "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the
4407      same cv-qualification as, or greater cv-qualification than, cv1,
4408      and B is not a virtual base class of D.  */
4409   /* We check this case before checking the validity of "TYPE t =
4410      EXPR;" below because for this case:
4411
4412        struct B {};
4413        struct D : public B { D(const B&); };
4414        extern B& b;
4415        void f() { static_cast<const D&>(b); }
4416
4417      we want to avoid constructing a new D.  The standard is not
4418      completely clear about this issue, but our interpretation is
4419      consistent with other compilers.  */
4420   if (TREE_CODE (type) == REFERENCE_TYPE
4421       && CLASS_TYPE_P (TREE_TYPE (type))
4422       && CLASS_TYPE_P (intype)
4423       && real_lvalue_p (expr)
4424       && DERIVED_FROM_P (intype, TREE_TYPE (type))
4425       && can_convert (build_pointer_type (TYPE_MAIN_VARIANT (intype)),
4426                       build_pointer_type (TYPE_MAIN_VARIANT
4427                                           (TREE_TYPE (type))))
4428       && at_least_as_qualified_p (TREE_TYPE (type), intype))
4429     {
4430       /* There is a standard conversion from "D*" to "B*" even if "B"
4431          is ambiguous or inaccessible.  Therefore, we ask lookup_base
4432          to check these conditions.  */
4433       tree base = lookup_base (TREE_TYPE (type), intype, ba_check, NULL);
4434
4435       /* Convert from "B*" to "D*".  This function will check that "B"
4436          is not a virtual base of "D".  */
4437       expr = build_base_path (MINUS_EXPR, build_address (expr),
4438                               base, /*nonnull=*/false);
4439       /* Convert the pointer to a reference -- but then remember that
4440          there are no expressions with reference type in C++.  */
4441       return convert_from_reference (build_nop (type, expr));
4442     }
4443
4444   /* [expr.static.cast]
4445
4446      An expression e can be explicitly converted to a type T using a
4447      static_cast of the form static_cast<T>(e) if the declaration T
4448      t(e);" is well-formed, for some invented temporary variable
4449      t.  */
4450   result = perform_direct_initialization_if_possible (type, expr);
4451   if (result)
4452     return convert_from_reference (result);
4453
4454   /* [expr.static.cast]
4455
4456      Any expression can be explicitly converted to type cv void.  */
4457   if (TREE_CODE (type) == VOID_TYPE)
4458     return convert_to_void (expr, /*implicit=*/NULL);
4459
4460   /* [expr.static.cast]
4461
4462      The inverse of any standard conversion sequence (clause _conv_),
4463      other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer
4464      (_conv.array_), function-to-pointer (_conv.func_), and boolean
4465      (_conv.bool_) conversions, can be performed explicitly using
4466      static_cast subject to the restriction that the explicit
4467      conversion does not cast away constness (_expr.const.cast_), and
4468      the following additional rules for specific cases:  */
4469   /* For reference, the conversions not excluded are: integral
4470      promotions, floating point promotion, integral conversions,
4471      floating point conversions, floating-integral conversions,
4472      pointer conversions, and pointer to member conversions.  */
4473   if ((ARITHMETIC_TYPE_P (type) && ARITHMETIC_TYPE_P (intype))
4474       /* DR 128
4475
4476          A value of integral _or enumeration_ type can be explicitly
4477          converted to an enumeration type.  */
4478       || (INTEGRAL_OR_ENUMERATION_TYPE_P (type)
4479           && INTEGRAL_OR_ENUMERATION_TYPE_P (intype)))
4480     /* Really, build_c_cast should defer to this function rather
4481        than the other way around.  */
4482     return build_c_cast (type, expr);
4483
4484   if (TYPE_PTR_P (type) && TYPE_PTR_P (intype)
4485       && CLASS_TYPE_P (TREE_TYPE (type))
4486       && CLASS_TYPE_P (TREE_TYPE (intype))
4487       && can_convert (build_pointer_type (TYPE_MAIN_VARIANT
4488                                           (TREE_TYPE (intype))),
4489                       build_pointer_type (TYPE_MAIN_VARIANT
4490                                           (TREE_TYPE (type)))))
4491     {
4492       tree base;
4493
4494       check_for_casting_away_constness (intype, type, "static_cast");
4495       base = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), ba_check,
4496                           NULL);
4497       return build_base_path (MINUS_EXPR, expr, base, /*nonnull=*/false);
4498     }
4499
4500   if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
4501       || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
4502     {
4503       tree c1;
4504       tree c2;
4505       tree t1;
4506       tree t2;
4507
4508       c1 = TYPE_PTRMEM_CLASS_TYPE (intype);
4509       c2 = TYPE_PTRMEM_CLASS_TYPE (type);
4510
4511       if (TYPE_PTRMEM_P (type))
4512         {
4513           t1 = (build_ptrmem_type
4514                 (c1,
4515                  TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (intype))));
4516           t2 = (build_ptrmem_type
4517                 (c2,
4518                  TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (type))));
4519         }
4520       else
4521         {
4522           t1 = intype;
4523           t2 = type;
4524         }
4525       if (can_convert (t1, t2))
4526         {
4527           check_for_casting_away_constness (intype, type, "static_cast");
4528           if (TYPE_PTRMEM_P (type))
4529             {
4530               tree delta;
4531
4532               if (TREE_CODE (expr) == PTRMEM_CST)
4533                 expr = cplus_expand_constant (expr);
4534               delta = get_delta_difference (c1, c2, /*force=*/1);
4535               if (!integer_zerop (delta))
4536                 expr = cp_build_binary_op (PLUS_EXPR,
4537                                            build_nop (ptrdiff_type_node, expr),
4538                                            delta);
4539               return build_nop (type, expr);
4540             }
4541           else
4542             return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr,
4543                                      /*force=*/1);
4544         }
4545     }
4546
4547   /* [expr.static.cast]
4548
4549      An rvalue of type "pointer to cv void" can be explicitly
4550      converted to a pointer to object type.  A value of type pointer
4551      to object converted to "pointer to cv void" and back to the
4552      original pointer type will have its original value.  */
4553   if (TREE_CODE (intype) == POINTER_TYPE
4554       && VOID_TYPE_P (TREE_TYPE (intype))
4555       && TYPE_PTROB_P (type))
4556     {
4557       check_for_casting_away_constness (intype, type, "static_cast");
4558       return build_nop (type, expr);
4559     }
4560
4561   error ("invalid static_cast from type `%T' to type `%T'", intype, type);
4562   return error_mark_node;
4563 }
4564
4565 tree
4566 build_reinterpret_cast (tree type, tree expr)
4567 {
4568   tree intype;
4569
4570   if (type == error_mark_node || expr == error_mark_node)
4571     return error_mark_node;
4572
4573   if (processing_template_decl)
4574     {
4575       tree t = build_min (REINTERPRET_CAST_EXPR, type, expr);
4576
4577       if (!TREE_SIDE_EFFECTS (t)
4578           && type_dependent_expression_p (expr))
4579         /* There might turn out to be side effects inside expr.  */
4580         TREE_SIDE_EFFECTS (t) = 1;
4581       return t;
4582     }
4583
4584   if (TREE_CODE (type) != REFERENCE_TYPE)
4585     {
4586       expr = decay_conversion (expr);
4587
4588       /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4589          Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4590       if (TREE_CODE (expr) == NOP_EXPR
4591           && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4592         expr = TREE_OPERAND (expr, 0);
4593     }
4594
4595   intype = TREE_TYPE (expr);
4596
4597   if (TREE_CODE (type) == REFERENCE_TYPE)
4598     {
4599       if (! real_lvalue_p (expr))
4600         {
4601           error ("invalid reinterpret_cast of an rvalue expression of type `%T' to type `%T'", intype, type);
4602           return error_mark_node;
4603         }
4604       expr = build_unary_op (ADDR_EXPR, expr, 0);
4605       if (expr != error_mark_node)
4606         expr = build_reinterpret_cast
4607           (build_pointer_type (TREE_TYPE (type)), expr);
4608       if (expr != error_mark_node)
4609         expr = build_indirect_ref (expr, 0);
4610       return expr;
4611     }
4612   else if (same_type_ignoring_top_level_qualifiers_p (intype, type))
4613     return build_static_cast (type, expr);
4614
4615   if (TYPE_PTR_P (type) && (TREE_CODE (intype) == INTEGER_TYPE
4616                             || TREE_CODE (intype) == ENUMERAL_TYPE))
4617     /* OK */;
4618   else if (TREE_CODE (type) == INTEGER_TYPE && TYPE_PTR_P (intype))
4619     {
4620       if (TYPE_PRECISION (type) < TYPE_PRECISION (intype))
4621         pedwarn ("reinterpret_cast from `%T' to `%T' loses precision",
4622                     intype, type);
4623     }
4624   else if ((TYPE_PTRFN_P (type) && TYPE_PTRFN_P (intype))
4625            || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
4626     {
4627       expr = decl_constant_value (expr);
4628       return fold (build1 (NOP_EXPR, type, expr));
4629     }
4630   else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
4631            || (TYPE_PTROBV_P (type) && TYPE_PTROBV_P (intype)))
4632     {
4633       check_for_casting_away_constness (intype, type, "reinterpret_cast");
4634       expr = decl_constant_value (expr);
4635       return fold (build1 (NOP_EXPR, type, expr));
4636     }
4637   else if ((TYPE_PTRFN_P (type) && TYPE_PTROBV_P (intype))
4638            || (TYPE_PTRFN_P (intype) && TYPE_PTROBV_P (type)))
4639     {
4640       pedwarn ("ISO C++ forbids casting between pointer-to-function and pointer-to-object");
4641       expr = decl_constant_value (expr);
4642       return fold (build1 (NOP_EXPR, type, expr));
4643     }
4644   else
4645     {
4646       error ("invalid reinterpret_cast from type `%T' to type `%T'",
4647                 intype, type);
4648       return error_mark_node;
4649     }
4650
4651   return cp_convert (type, expr);
4652 }
4653
4654 tree
4655 build_const_cast (tree type, tree expr)
4656 {
4657   tree intype;
4658
4659   if (type == error_mark_node || expr == error_mark_node)
4660     return error_mark_node;
4661
4662   if (processing_template_decl)
4663     {
4664       tree t = build_min (CONST_CAST_EXPR, type, expr);
4665
4666       if (!TREE_SIDE_EFFECTS (t)
4667           && type_dependent_expression_p (expr))
4668         /* There might turn out to be side effects inside expr.  */
4669         TREE_SIDE_EFFECTS (t) = 1;
4670       return t;
4671     }
4672
4673   if (!POINTER_TYPE_P (type))
4674     error ("invalid use of const_cast with type `%T', which is not a pointer, reference, nor a pointer-to-data-member type", type);
4675   else if (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4676     {
4677       error ("invalid use of const_cast with type `%T', which is a pointer or reference to a function type", type);
4678       return error_mark_node;
4679     }
4680
4681   if (TREE_CODE (type) != REFERENCE_TYPE)
4682     {
4683       expr = decay_conversion (expr);
4684
4685       /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4686          Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4687       if (TREE_CODE (expr) == NOP_EXPR
4688           && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4689         expr = TREE_OPERAND (expr, 0);
4690     }
4691
4692   intype = TREE_TYPE (expr);
4693
4694   if (same_type_ignoring_top_level_qualifiers_p (intype, type))
4695     return build_static_cast (type, expr);
4696   else if (TREE_CODE (type) == REFERENCE_TYPE)
4697     {
4698       if (! real_lvalue_p (expr))
4699         {
4700           error ("invalid const_cast of an rvalue of type `%T' to type `%T'", intype, type);
4701           return error_mark_node;
4702         }
4703
4704       if (comp_ptr_ttypes_const (TREE_TYPE (type), intype))
4705         {
4706           expr = build_unary_op (ADDR_EXPR, expr, 0);
4707           expr = build1 (NOP_EXPR, type, expr);
4708           return convert_from_reference (expr);
4709         }
4710     }
4711   else if (((TREE_CODE (type) == POINTER_TYPE
4712              && TREE_CODE (intype) == POINTER_TYPE)
4713             || (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)))
4714            && comp_ptr_ttypes_const (TREE_TYPE (type), TREE_TYPE (intype)))
4715     return cp_convert (type, expr);
4716
4717   error ("invalid const_cast from type `%T' to type `%T'", intype, type);
4718   return error_mark_node;
4719 }
4720
4721 /* Build an expression representing a cast to type TYPE of expression EXPR.
4722
4723    ALLOW_NONCONVERTING is true if we should allow non-converting constructors
4724    when doing the cast.  */
4725
4726 tree
4727 build_c_cast (tree type, tree expr)
4728 {
4729   register tree value = expr;
4730   tree otype;
4731
4732   if (type == error_mark_node || expr == error_mark_node)
4733     return error_mark_node;
4734
4735   if (processing_template_decl)
4736     {
4737       tree t = build_min (CAST_EXPR, type,
4738                           tree_cons (NULL_TREE, value, NULL_TREE));
4739       /* We don't know if it will or will not have side effects. */
4740       TREE_SIDE_EFFECTS (t) = 1;
4741       return t;
4742     }
4743
4744   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4745      Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4746   if (TREE_CODE (type) != REFERENCE_TYPE
4747       && TREE_CODE (value) == NOP_EXPR
4748       && TREE_TYPE (value) == TREE_TYPE (TREE_OPERAND (value, 0)))
4749     value = TREE_OPERAND (value, 0);
4750
4751   if (TREE_CODE (type) == ARRAY_TYPE)
4752     {
4753       /* Allow casting from T1* to T2[] because Cfront allows it.
4754          NIHCL uses it. It is not valid ISO C++ however.  */
4755       if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
4756         {
4757           pedwarn ("ISO C++ forbids casting to an array type `%T'", type);
4758           type = build_pointer_type (TREE_TYPE (type));
4759         }
4760       else
4761         {
4762           error ("ISO C++ forbids casting to an array type `%T'", type);
4763           return error_mark_node;
4764         }
4765     }
4766
4767   if (TREE_CODE (type) == FUNCTION_TYPE
4768       || TREE_CODE (type) == METHOD_TYPE)
4769     {
4770       error ("invalid cast to function type `%T'", type);
4771       return error_mark_node;
4772     }
4773
4774   if (TREE_CODE (type) == VOID_TYPE)
4775     {
4776       /* Conversion to void does not cause any of the normal function to
4777        * pointer, array to pointer and lvalue to rvalue decays.  */
4778
4779       value = convert_to_void (value, /*implicit=*/NULL);
4780       return value;
4781     }
4782
4783   if (!complete_type_or_else (type, NULL_TREE))
4784     return error_mark_node;
4785
4786   /* Convert functions and arrays to pointers and
4787      convert references to their expanded types,
4788      but don't convert any other types.  If, however, we are
4789      casting to a class type, there's no reason to do this: the
4790      cast will only succeed if there is a converting constructor,
4791      and the default conversions will be done at that point.  In
4792      fact, doing the default conversion here is actually harmful
4793      in cases like this:
4794
4795      typedef int A[2];
4796      struct S { S(const A&); };
4797
4798      since we don't want the array-to-pointer conversion done.  */
4799   if (!IS_AGGR_TYPE (type))
4800     {
4801       if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
4802           || (TREE_CODE (TREE_TYPE (value)) == METHOD_TYPE
4803               /* Don't do the default conversion on a ->* expression.  */
4804               && ! (TREE_CODE (type) == POINTER_TYPE
4805                     && bound_pmf_p (value)))
4806           || TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
4807           || TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE)
4808         value = decay_conversion (value);
4809     }
4810   else if (TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE)
4811     /* However, even for class types, we still need to strip away
4812        the reference type, since the call to convert_force below
4813        does not expect the input expression to be of reference
4814        type.  */
4815     value = convert_from_reference (value);
4816
4817   otype = TREE_TYPE (value);
4818
4819   /* Optionally warn about potentially worrisome casts.  */
4820
4821   if (warn_cast_qual
4822       && TREE_CODE (type) == POINTER_TYPE
4823       && TREE_CODE (otype) == POINTER_TYPE
4824       && !at_least_as_qualified_p (TREE_TYPE (type),
4825                                    TREE_TYPE (otype)))
4826     warning ("cast from `%T' to `%T' discards qualifiers from pointer target type",
4827                 otype, type);
4828
4829   if (TREE_CODE (type) == INTEGER_TYPE
4830       && TYPE_PTR_P (otype)
4831       && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4832     warning ("cast from pointer to integer of different size");
4833
4834   if (TYPE_PTR_P (type)
4835       && TREE_CODE (otype) == INTEGER_TYPE
4836       && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4837       /* Don't warn about converting any constant.  */
4838       && !TREE_CONSTANT (value))
4839     warning ("cast to pointer from integer of different size");
4840
4841   if (TREE_CODE (type) == REFERENCE_TYPE)
4842     value = (convert_from_reference
4843              (convert_to_reference (type, value, CONV_C_CAST,
4844                                     LOOKUP_COMPLAIN, NULL_TREE)));
4845   else
4846     {
4847       tree ovalue;
4848
4849       value = decl_constant_value (value);
4850
4851       ovalue = value;
4852       value = convert_force (type, value, CONV_C_CAST);
4853
4854       /* Ignore any integer overflow caused by the cast.  */
4855       if (TREE_CODE (value) == INTEGER_CST)
4856         {
4857           TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4858           TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
4859         }
4860     }
4861
4862   /* Warn about possible alignment problems.  Do this here when we will have
4863      instantiated any necessary template types.  */
4864   if (STRICT_ALIGNMENT && warn_cast_align
4865       && TREE_CODE (type) == POINTER_TYPE
4866       && TREE_CODE (otype) == POINTER_TYPE
4867       && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4868       && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4869       && COMPLETE_TYPE_P (TREE_TYPE (otype))
4870       && COMPLETE_TYPE_P (TREE_TYPE (type))
4871       && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4872     warning ("cast from `%T' to `%T' increases required alignment of target type",
4873                 otype, type);
4874
4875     /* Always produce some operator for an explicit cast,
4876        so we can tell (for -pedantic) that the cast is no lvalue.  */
4877   if (TREE_CODE (type) != REFERENCE_TYPE && value == expr
4878       && real_lvalue_p (value))
4879     value = non_lvalue (value);
4880
4881   return value;
4882 }
4883 \f
4884 /* Build an assignment expression of lvalue LHS from value RHS.
4885    MODIFYCODE is the code for a binary operator that we use
4886    to combine the old value of LHS with RHS to get the new value.
4887    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4888
4889    C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed.  */
4890
4891 tree
4892 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
4893 {
4894   register tree result;
4895   tree newrhs = rhs;
4896   tree lhstype = TREE_TYPE (lhs);
4897   tree olhstype = lhstype;
4898   tree olhs = lhs;
4899
4900   /* Avoid duplicate error messages from operands that had errors.  */
4901   if (lhs == error_mark_node || rhs == error_mark_node)
4902     return error_mark_node;
4903
4904   /* Handle control structure constructs used as "lvalues".  */
4905   switch (TREE_CODE (lhs))
4906     {
4907       /* Handle --foo = 5; as these are valid constructs in C++ */
4908     case PREDECREMENT_EXPR:
4909     case PREINCREMENT_EXPR:
4910       if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
4911         lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs),
4912                      stabilize_reference (TREE_OPERAND (lhs, 0)),
4913                      TREE_OPERAND (lhs, 1));
4914       return build (COMPOUND_EXPR, lhstype,
4915                     lhs,
4916                     build_modify_expr (TREE_OPERAND (lhs, 0),
4917                                        modifycode, rhs));
4918
4919       /* Handle (a, b) used as an "lvalue".  */
4920     case COMPOUND_EXPR:
4921       newrhs = build_modify_expr (TREE_OPERAND (lhs, 1),
4922                                   modifycode, rhs);
4923       if (newrhs == error_mark_node)
4924         return error_mark_node;
4925       return build (COMPOUND_EXPR, lhstype,
4926                     TREE_OPERAND (lhs, 0), newrhs);
4927
4928     case MODIFY_EXPR:
4929       if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
4930         lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs),
4931                      stabilize_reference (TREE_OPERAND (lhs, 0)),
4932                      TREE_OPERAND (lhs, 1));
4933       newrhs = build_modify_expr (TREE_OPERAND (lhs, 0), modifycode, rhs);
4934       if (newrhs == error_mark_node)
4935         return error_mark_node;
4936       return build (COMPOUND_EXPR, lhstype, lhs, newrhs);
4937
4938       /* Handle (a ? b : c) used as an "lvalue".  */
4939     case COND_EXPR:
4940       {
4941         /* Produce (a ? (b = rhs) : (c = rhs))
4942            except that the RHS goes through a save-expr
4943            so the code to compute it is only emitted once.  */
4944         tree cond;
4945         tree preeval = NULL_TREE;
4946
4947         rhs = stabilize_expr (rhs, &preeval);
4948
4949         /* Check this here to avoid odd errors when trying to convert
4950            a throw to the type of the COND_EXPR.  */
4951         if (!lvalue_or_else (lhs, "assignment"))
4952           return error_mark_node;
4953
4954         cond = build_conditional_expr
4955           (TREE_OPERAND (lhs, 0),
4956            build_modify_expr (cp_convert (TREE_TYPE (lhs),
4957                                           TREE_OPERAND (lhs, 1)),
4958                               modifycode, rhs),
4959            build_modify_expr (cp_convert (TREE_TYPE (lhs),
4960                                           TREE_OPERAND (lhs, 2)),
4961                               modifycode, rhs));
4962
4963         if (cond == error_mark_node)
4964           return cond;
4965         /* Make sure the code to compute the rhs comes out
4966            before the split.  */
4967         return build (COMPOUND_EXPR, TREE_TYPE (lhs), preeval, cond);
4968       }
4969
4970     default:
4971       break;
4972     }
4973
4974   if (modifycode == INIT_EXPR)
4975     {
4976       if (TREE_CODE (rhs) == CONSTRUCTOR)
4977         {
4978           my_friendly_assert (same_type_p (TREE_TYPE (rhs), lhstype),
4979                               20011220);
4980           result = build (INIT_EXPR, lhstype, lhs, rhs);
4981           TREE_SIDE_EFFECTS (result) = 1;
4982           return result;
4983         }
4984       else if (! IS_AGGR_TYPE (lhstype))
4985         /* Do the default thing */;
4986       else
4987         {
4988           result = build_special_member_call (lhs, complete_ctor_identifier,
4989                                               build_tree_list (NULL_TREE, rhs),
4990                                               TYPE_BINFO (lhstype),
4991                                               LOOKUP_NORMAL);
4992           if (result == NULL_TREE)
4993             return error_mark_node;
4994           return result;
4995         }
4996     }
4997   else
4998     {
4999       if (TREE_CODE (lhstype) == REFERENCE_TYPE)
5000         {
5001           lhs = convert_from_reference (lhs);
5002           olhstype = lhstype = TREE_TYPE (lhs);
5003         }
5004       lhs = require_complete_type (lhs);
5005       if (lhs == error_mark_node)
5006         return error_mark_node;
5007
5008       if (modifycode == NOP_EXPR)
5009         {
5010           /* `operator=' is not an inheritable operator.  */
5011           if (! IS_AGGR_TYPE (lhstype))
5012             /* Do the default thing */;
5013           else
5014             {
5015               result = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL,
5016                                      lhs, rhs, make_node (NOP_EXPR));
5017               if (result == NULL_TREE)
5018                 return error_mark_node;
5019               return result;
5020             }
5021           lhstype = olhstype;
5022         }
5023       else
5024         {
5025           /* A binary op has been requested.  Combine the old LHS
5026              value with the RHS producing the value we should actually
5027              store into the LHS.  */
5028
5029           my_friendly_assert (!PROMOTES_TO_AGGR_TYPE (lhstype, REFERENCE_TYPE),
5030                               978652);
5031           lhs = stabilize_reference (lhs);
5032           newrhs = cp_build_binary_op (modifycode, lhs, rhs);
5033           if (newrhs == error_mark_node)
5034             {
5035               error ("  in evaluation of `%Q(%#T, %#T)'", modifycode,
5036                      TREE_TYPE (lhs), TREE_TYPE (rhs));
5037               return error_mark_node;
5038             }
5039
5040           /* Now it looks like a plain assignment.  */
5041           modifycode = NOP_EXPR;
5042         }
5043       my_friendly_assert (TREE_CODE (lhstype) != REFERENCE_TYPE, 20011220);
5044       my_friendly_assert (TREE_CODE (TREE_TYPE (newrhs)) != REFERENCE_TYPE,
5045                           20011220);
5046     }
5047
5048   /* Handle a cast used as an "lvalue".
5049      We have already performed any binary operator using the value as cast.
5050      Now convert the result to the cast type of the lhs,
5051      and then true type of the lhs and store it there;
5052      then convert result back to the cast type to be the value
5053      of the assignment.  */
5054
5055   switch (TREE_CODE (lhs))
5056     {
5057     case NOP_EXPR:
5058     case CONVERT_EXPR:
5059     case FLOAT_EXPR:
5060     case FIX_TRUNC_EXPR:
5061     case FIX_FLOOR_EXPR:
5062     case FIX_ROUND_EXPR:
5063     case FIX_CEIL_EXPR:
5064       {
5065         tree inner_lhs = TREE_OPERAND (lhs, 0);
5066         tree result;
5067
5068         if (TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE
5069             || TREE_CODE (TREE_TYPE (newrhs)) == FUNCTION_TYPE
5070             || TREE_CODE (TREE_TYPE (newrhs)) == METHOD_TYPE
5071             || TREE_CODE (TREE_TYPE (newrhs)) == OFFSET_TYPE)
5072           newrhs = decay_conversion (newrhs);
5073
5074         /* ISO C++ 5.4/1: The result is an lvalue if T is a reference
5075            type, otherwise the result is an rvalue.  */
5076         if (! lvalue_p (lhs))
5077           pedwarn ("ISO C++ forbids cast to non-reference type used as lvalue");
5078
5079         result = build_modify_expr (inner_lhs, NOP_EXPR,
5080                                     cp_convert (TREE_TYPE (inner_lhs),
5081                                                 cp_convert (lhstype, newrhs)));
5082         if (result == error_mark_node)
5083           return result;
5084         return cp_convert (TREE_TYPE (lhs), result);
5085       }
5086
5087     default:
5088       break;
5089     }
5090
5091   /* Now we have handled acceptable kinds of LHS that are not truly lvalues.
5092      Reject anything strange now.  */
5093
5094   if (!lvalue_or_else (lhs, "assignment"))
5095     return error_mark_node;
5096
5097   /* Warn about modifying something that is `const'.  Don't warn if
5098      this is initialization.  */
5099   if (modifycode != INIT_EXPR
5100       && (TREE_READONLY (lhs) || CP_TYPE_CONST_P (lhstype)
5101           /* Functions are not modifiable, even though they are
5102              lvalues.  */
5103           || TREE_CODE (TREE_TYPE (lhs)) == FUNCTION_TYPE
5104           || TREE_CODE (TREE_TYPE (lhs)) == METHOD_TYPE
5105           /* If it's an aggregate and any field is const, then it is
5106              effectively const.  */
5107           || (CLASS_TYPE_P (lhstype)
5108               && C_TYPE_FIELDS_READONLY (lhstype))))
5109     readonly_error (lhs, "assignment", 0);
5110
5111   /* If storing into a structure or union member, it has probably been
5112      given type `int'.  Compute the type that would go with the actual
5113      amount of storage the member occupies.  */
5114
5115   if (TREE_CODE (lhs) == COMPONENT_REF
5116       && (TREE_CODE (lhstype) == INTEGER_TYPE
5117           || TREE_CODE (lhstype) == REAL_TYPE
5118           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
5119     {
5120       lhstype = TREE_TYPE (get_unwidened (lhs, 0));
5121
5122       /* If storing in a field that is in actuality a short or narrower
5123          than one, we must store in the field in its actual type.  */
5124
5125       if (lhstype != TREE_TYPE (lhs))
5126         {
5127           lhs = copy_node (lhs);
5128           TREE_TYPE (lhs) = lhstype;
5129         }
5130     }
5131
5132   /* Convert new value to destination type.  */
5133
5134   if (TREE_CODE (lhstype) == ARRAY_TYPE)
5135     {
5136       int from_array;
5137
5138       if (!same_or_base_type_p (TYPE_MAIN_VARIANT (lhstype),
5139                                 TYPE_MAIN_VARIANT (TREE_TYPE (rhs))))
5140         {
5141           error ("incompatible types in assignment of `%T' to `%T'",
5142                  TREE_TYPE (rhs), lhstype);
5143           return error_mark_node;
5144         }
5145
5146       /* Allow array assignment in compiler-generated code.  */
5147       if (! DECL_ARTIFICIAL (current_function_decl))
5148         pedwarn ("ISO C++ forbids assignment of arrays");
5149
5150       from_array = TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE
5151                    ? 1 + (modifycode != INIT_EXPR): 0;
5152       return build_vec_init (lhs, NULL_TREE, newrhs, from_array);
5153     }
5154
5155   if (modifycode == INIT_EXPR)
5156     newrhs = convert_for_initialization (lhs, lhstype, newrhs, LOOKUP_NORMAL,
5157                                          "initialization", NULL_TREE, 0);
5158   else
5159     {
5160       /* Avoid warnings on enum bit fields.  */
5161       if (TREE_CODE (olhstype) == ENUMERAL_TYPE
5162           && TREE_CODE (lhstype) == INTEGER_TYPE)
5163         {
5164           newrhs = convert_for_assignment (olhstype, newrhs, "assignment",
5165                                            NULL_TREE, 0);
5166           newrhs = convert_force (lhstype, newrhs, 0);
5167         }
5168       else
5169         newrhs = convert_for_assignment (lhstype, newrhs, "assignment",
5170                                          NULL_TREE, 0);
5171       if (TREE_CODE (newrhs) == CALL_EXPR
5172           && TYPE_NEEDS_CONSTRUCTING (lhstype))
5173         newrhs = build_cplus_new (lhstype, newrhs);
5174
5175       /* Can't initialize directly from a TARGET_EXPR, since that would
5176          cause the lhs to be constructed twice, and possibly result in
5177          accidental self-initialization.  So we force the TARGET_EXPR to be
5178          expanded without a target.  */
5179       if (TREE_CODE (newrhs) == TARGET_EXPR)
5180         newrhs = build (COMPOUND_EXPR, TREE_TYPE (newrhs), newrhs,
5181                         TREE_OPERAND (newrhs, 0));
5182     }
5183
5184   if (newrhs == error_mark_node)
5185     return error_mark_node;
5186
5187   result = build (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR,
5188                   lhstype, lhs, newrhs);
5189
5190   TREE_SIDE_EFFECTS (result) = 1;
5191
5192   /* If we got the LHS in a different type for storing in,
5193      convert the result back to the nominal type of LHS
5194      so that the value we return always has the same type
5195      as the LHS argument.  */
5196
5197   if (olhstype == TREE_TYPE (result))
5198     return result;
5199   /* Avoid warnings converting integral types back into enums
5200      for enum bit fields.  */
5201   if (TREE_CODE (TREE_TYPE (result)) == INTEGER_TYPE
5202       && TREE_CODE (olhstype) == ENUMERAL_TYPE)
5203     {
5204       result = build (COMPOUND_EXPR, olhstype, result, olhs);
5205       TREE_NO_UNUSED_WARNING (result) = 1;
5206       return result;
5207     }
5208   return convert_for_assignment (olhstype, result, "assignment",
5209                                  NULL_TREE, 0);
5210 }
5211
5212 tree
5213 build_x_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
5214 {
5215   if (processing_template_decl)
5216     return build_min_nt (MODOP_EXPR, lhs,
5217                          build_min_nt (modifycode, NULL_TREE, NULL_TREE), rhs);
5218
5219   if (modifycode != NOP_EXPR)
5220     {
5221       tree rval = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, lhs, rhs,
5222                                 make_node (modifycode));
5223       if (rval)
5224         return rval;
5225     }
5226   return build_modify_expr (lhs, modifycode, rhs);
5227 }
5228
5229 \f
5230 /* Get difference in deltas for different pointer to member function
5231    types.  Returns an integer constant of type PTRDIFF_TYPE_NODE.  If
5232    the conversion is invalid, the constant is zero.  If FORCE is true,
5233    then allow reverse conversions as well.
5234
5235    Note that the naming of FROM and TO is kind of backwards; the return
5236    value is what we add to a TO in order to get a FROM.  They are named
5237    this way because we call this function to find out how to convert from
5238    a pointer to member of FROM to a pointer to member of TO.  */
5239
5240 static tree
5241 get_delta_difference (tree from, tree to, int force)
5242 {
5243   tree binfo;
5244   tree virt_binfo;
5245   base_kind kind;
5246
5247   binfo = lookup_base (to, from, ba_check, &kind);
5248   if (kind == bk_inaccessible || kind == bk_ambig)
5249     {
5250       error ("   in pointer to member function conversion");
5251       goto error;
5252     }
5253   if (!binfo)
5254     {
5255       if (!force)
5256         {
5257           error_not_base_type (from, to);
5258           error ("   in pointer to member conversion");
5259           goto error;
5260         }
5261       binfo = lookup_base (from, to, ba_check, &kind);
5262       if (!binfo)
5263         goto error;
5264       virt_binfo = binfo_from_vbase (binfo);
5265       if (virt_binfo)
5266         {
5267           /* This is a reinterpret cast, we choose to do nothing.  */
5268           warning ("pointer to member cast via virtual base `%T'",
5269                    BINFO_TYPE (virt_binfo));
5270           goto error;
5271         }
5272       return convert_to_integer (ptrdiff_type_node,
5273                                  size_diffop (size_zero_node,
5274                                               BINFO_OFFSET (binfo)));
5275     }
5276
5277   virt_binfo = binfo_from_vbase (binfo);
5278   if (!virt_binfo)
5279     return convert_to_integer (ptrdiff_type_node, BINFO_OFFSET (binfo));
5280
5281   /* This is a reinterpret cast, we choose to do nothing.  */
5282   if (force)
5283     warning ("pointer to member cast via virtual base `%T'",
5284              BINFO_TYPE (virt_binfo));
5285   else
5286     error ("pointer to member conversion via virtual base `%T'",
5287            BINFO_TYPE (virt_binfo));
5288
5289  error:
5290   return convert_to_integer(ptrdiff_type_node, integer_zero_node);
5291 }
5292
5293 /* Return a constructor for the pointer-to-member-function TYPE using
5294    the other components as specified.  */
5295
5296 tree
5297 build_ptrmemfunc1 (tree type, tree delta, tree pfn)
5298 {
5299   tree u = NULL_TREE;
5300   tree delta_field;
5301   tree pfn_field;
5302
5303   /* Pull the FIELD_DECLs out of the type.  */
5304   pfn_field = TYPE_FIELDS (type);
5305   delta_field = TREE_CHAIN (pfn_field);
5306
5307   /* Make sure DELTA has the type we want.  */
5308   delta = convert_and_check (delta_type_node, delta);
5309
5310   /* Finish creating the initializer.  */
5311   u = tree_cons (pfn_field, pfn,
5312                  build_tree_list (delta_field, delta));
5313   u = build_constructor (type, u);
5314   TREE_CONSTANT (u) = TREE_CONSTANT (pfn) && TREE_CONSTANT (delta);
5315   TREE_STATIC (u) = (TREE_CONSTANT (u)
5316                      && (initializer_constant_valid_p (pfn, TREE_TYPE (pfn))
5317                          != NULL_TREE)
5318                      && (initializer_constant_valid_p (delta, TREE_TYPE (delta))
5319                          != NULL_TREE));
5320   return u;
5321 }
5322
5323 /* Build a constructor for a pointer to member function.  It can be
5324    used to initialize global variables, local variable, or used
5325    as a value in expressions.  TYPE is the POINTER to METHOD_TYPE we
5326    want to be.
5327
5328    If FORCE is nonzero, then force this conversion, even if
5329    we would rather not do it.  Usually set when using an explicit
5330    cast.
5331
5332    Return error_mark_node, if something goes wrong.  */
5333
5334 tree
5335 build_ptrmemfunc (tree type, tree pfn, int force)
5336 {
5337   tree fn;
5338   tree pfn_type;
5339   tree to_type;
5340
5341   if (error_operand_p (pfn))
5342     return error_mark_node;
5343
5344   pfn_type = TREE_TYPE (pfn);
5345   to_type = build_ptrmemfunc_type (type);
5346
5347   /* Handle multiple conversions of pointer to member functions.  */
5348   if (TYPE_PTRMEMFUNC_P (pfn_type))
5349     {
5350       tree delta = NULL_TREE;
5351       tree npfn = NULL_TREE;
5352       tree n;
5353
5354       if (!force
5355           && !can_convert_arg (to_type, TREE_TYPE (pfn), pfn))
5356         error ("invalid conversion to type `%T' from type `%T'",
5357                   to_type, pfn_type);
5358
5359       n = get_delta_difference (TYPE_PTRMEMFUNC_OBJECT_TYPE (pfn_type),
5360                                 TYPE_PTRMEMFUNC_OBJECT_TYPE (to_type),
5361                                 force);
5362
5363       /* We don't have to do any conversion to convert a
5364          pointer-to-member to its own type.  But, we don't want to
5365          just return a PTRMEM_CST if there's an explicit cast; that
5366          cast should make the expression an invalid template argument.  */
5367       if (TREE_CODE (pfn) != PTRMEM_CST)
5368         {
5369           if (same_type_p (to_type, pfn_type))
5370             return pfn;
5371           else if (integer_zerop (n))
5372             return build_reinterpret_cast (to_type, pfn);
5373         }
5374
5375       if (TREE_SIDE_EFFECTS (pfn))
5376         pfn = save_expr (pfn);
5377
5378       /* Obtain the function pointer and the current DELTA.  */
5379       if (TREE_CODE (pfn) == PTRMEM_CST)
5380         expand_ptrmemfunc_cst (pfn, &delta, &npfn);
5381       else
5382         {
5383           npfn = build_ptrmemfunc_access_expr (pfn, pfn_identifier);
5384           delta = build_ptrmemfunc_access_expr (pfn, delta_identifier);
5385         }
5386
5387       /* Just adjust the DELTA field.  */
5388       my_friendly_assert (TREE_TYPE (delta) == ptrdiff_type_node, 20030727);
5389       if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_delta)
5390         n = cp_build_binary_op (LSHIFT_EXPR, n, integer_one_node);
5391       delta = cp_build_binary_op (PLUS_EXPR, delta, n);
5392       return build_ptrmemfunc1 (to_type, delta, npfn);
5393     }
5394
5395   /* Handle null pointer to member function conversions.  */
5396   if (integer_zerop (pfn))
5397     {
5398       pfn = build_c_cast (type, integer_zero_node);
5399       return build_ptrmemfunc1 (to_type,
5400                                 integer_zero_node,
5401                                 pfn);
5402     }
5403
5404   if (type_unknown_p (pfn))
5405     return instantiate_type (type, pfn, tf_error | tf_warning);
5406
5407   fn = TREE_OPERAND (pfn, 0);
5408   my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0);
5409   return make_ptrmem_cst (to_type, fn);
5410 }
5411
5412 /* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST
5413    given by CST.
5414
5415    ??? There is no consistency as to the types returned for the above
5416    values.  Some code acts as if its a sizetype and some as if its
5417    integer_type_node.  */
5418
5419 void
5420 expand_ptrmemfunc_cst (tree cst, tree *delta, tree *pfn)
5421 {
5422   tree type = TREE_TYPE (cst);
5423   tree fn = PTRMEM_CST_MEMBER (cst);
5424   tree ptr_class, fn_class;
5425
5426   my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0);
5427
5428   /* The class that the function belongs to.  */
5429   fn_class = DECL_CONTEXT (fn);
5430
5431   /* The class that we're creating a pointer to member of.  */
5432   ptr_class = TYPE_PTRMEMFUNC_OBJECT_TYPE (type);
5433
5434   /* First, calculate the adjustment to the function's class.  */
5435   *delta = get_delta_difference (fn_class, ptr_class, /*force=*/0);
5436
5437   if (!DECL_VIRTUAL_P (fn))
5438     *pfn = convert (TYPE_PTRMEMFUNC_FN_TYPE (type), build_addr_func (fn));
5439   else
5440     {
5441       /* If we're dealing with a virtual function, we have to adjust 'this'
5442          again, to point to the base which provides the vtable entry for
5443          fn; the call will do the opposite adjustment.  */
5444       tree orig_class = DECL_CONTEXT (fn);
5445       tree binfo = binfo_or_else (orig_class, fn_class);
5446       *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta),
5447                             *delta, BINFO_OFFSET (binfo)));
5448
5449       /* We set PFN to the vtable offset at which the function can be
5450          found, plus one (unless ptrmemfunc_vbit_in_delta, in which
5451          case delta is shifted left, and then incremented).  */
5452       *pfn = DECL_VINDEX (fn);
5453       *pfn = fold (build (MULT_EXPR, integer_type_node, *pfn,
5454                           TYPE_SIZE_UNIT (vtable_entry_type)));
5455
5456       switch (TARGET_PTRMEMFUNC_VBIT_LOCATION)
5457         {
5458         case ptrmemfunc_vbit_in_pfn:
5459           *pfn = fold (build (PLUS_EXPR, integer_type_node, *pfn,
5460                               integer_one_node));
5461           break;
5462
5463         case ptrmemfunc_vbit_in_delta:
5464           *delta = fold (build (LSHIFT_EXPR, TREE_TYPE (*delta),
5465                                 *delta, integer_one_node));
5466           *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta),
5467                                 *delta, integer_one_node));
5468           break;
5469
5470         default:
5471           abort ();
5472         }
5473
5474       *pfn = fold (build1 (NOP_EXPR, TYPE_PTRMEMFUNC_FN_TYPE (type),
5475                            *pfn));
5476     }
5477 }
5478
5479 /* Return an expression for PFN from the pointer-to-member function
5480    given by T.  */
5481
5482 tree
5483 pfn_from_ptrmemfunc (tree t)
5484 {
5485   if (TREE_CODE (t) == PTRMEM_CST)
5486     {
5487       tree delta;
5488       tree pfn;
5489
5490       expand_ptrmemfunc_cst (t, &delta, &pfn);
5491       if (pfn)
5492         return pfn;
5493     }
5494
5495   return build_ptrmemfunc_access_expr (t, pfn_identifier);
5496 }
5497
5498 /* Expression EXPR is about to be implicitly converted to TYPE.  Warn
5499    if this is a potentially dangerous thing to do.  Returns a possibly
5500    marked EXPR.  */
5501
5502 tree
5503 dubious_conversion_warnings (tree type, tree expr,
5504                              const char *errtype, tree fndecl, int parmnum)
5505 {
5506   type = non_reference (type);
5507
5508   /* Issue warnings about peculiar, but valid, uses of NULL.  */
5509   if (ARITHMETIC_TYPE_P (type) && expr == null_node)
5510     {
5511       if (fndecl)
5512         warning ("passing NULL used for non-pointer %s %P of `%D'",
5513                     errtype, parmnum, fndecl);
5514       else
5515         warning ("%s to non-pointer type `%T' from NULL", errtype, type);
5516     }
5517
5518   /* Warn about assigning a floating-point type to an integer type.  */
5519   if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
5520       && TREE_CODE (type) == INTEGER_TYPE)
5521     {
5522       if (fndecl)
5523         warning ("passing `%T' for %s %P of `%D'",
5524                     TREE_TYPE (expr), errtype, parmnum, fndecl);
5525       else
5526         warning ("%s to `%T' from `%T'", errtype, type, TREE_TYPE (expr));
5527     }
5528   /* And warn about assigning a negative value to an unsigned
5529      variable.  */
5530   else if (TREE_UNSIGNED (type) && TREE_CODE (type) != BOOLEAN_TYPE)
5531     {
5532       if (TREE_CODE (expr) == INTEGER_CST
5533           && TREE_NEGATED_INT (expr))
5534         {
5535           if (fndecl)
5536             warning ("passing negative value `%E' for %s %P of `%D'",
5537                         expr, errtype, parmnum, fndecl);
5538           else
5539             warning ("%s of negative value `%E' to `%T'",
5540                         errtype, expr, type);
5541         }
5542
5543       overflow_warning (expr);
5544
5545       if (TREE_CONSTANT (expr))
5546         expr = fold (expr);
5547     }
5548   return expr;
5549 }
5550
5551 /* Convert value RHS to type TYPE as preparation for an assignment to
5552    an lvalue of type TYPE.  ERRTYPE is a string to use in error
5553    messages: "assignment", "return", etc.  If FNDECL is non-NULL, we
5554    are doing the conversion in order to pass the PARMNUMth argument of
5555    FNDECL.  */
5556
5557 static tree
5558 convert_for_assignment (tree type, tree rhs,
5559                         const char *errtype, tree fndecl, int parmnum)
5560 {
5561   register tree rhstype;
5562   register enum tree_code coder;
5563
5564   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
5565   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
5566     rhs = TREE_OPERAND (rhs, 0);
5567
5568   rhstype = TREE_TYPE (rhs);
5569   coder = TREE_CODE (rhstype);
5570
5571   if (TREE_CODE (type) == VECTOR_TYPE && coder == VECTOR_TYPE
5572       && ((*targetm.vector_opaque_p) (type)
5573           || (*targetm.vector_opaque_p) (rhstype)))
5574     return convert (type, rhs);
5575
5576   if (rhs == error_mark_node || rhstype == error_mark_node)
5577     return error_mark_node;
5578   if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)
5579     return error_mark_node;
5580
5581   rhs = dubious_conversion_warnings (type, rhs, errtype, fndecl, parmnum);
5582
5583   /* The RHS of an assignment cannot have void type.  */
5584   if (coder == VOID_TYPE)
5585     {
5586       error ("void value not ignored as it ought to be");
5587       return error_mark_node;
5588     }
5589
5590   /* Simplify the RHS if possible.  */
5591   if (TREE_CODE (rhs) == CONST_DECL)
5592     rhs = DECL_INITIAL (rhs);
5593
5594   /* We do not use decl_constant_value here because of this case:
5595
5596        const char* const s = "s";
5597
5598      The conversion rules for a string literal are more lax than for a
5599      variable; in particular, a string literal can be converted to a
5600      "char *" but the variable "s" cannot be converted in the same
5601      way.  If the conversion is allowed, the optimization should be
5602      performed while creating the converted expression.  */
5603
5604   /* [expr.ass]
5605
5606      The expression is implicitly converted (clause _conv_) to the
5607      cv-unqualified type of the left operand.
5608
5609      We allow bad conversions here because by the time we get to this point
5610      we are committed to doing the conversion.  If we end up doing a bad
5611      conversion, convert_like will complain.  */
5612   if (!can_convert_arg_bad (type, rhstype, rhs))
5613     {
5614       /* When -Wno-pmf-conversions is use, we just silently allow
5615          conversions from pointers-to-members to plain pointers.  If
5616          the conversion doesn't work, cp_convert will complain.  */
5617       if (!warn_pmf2ptr
5618           && TYPE_PTR_P (type)
5619           && TYPE_PTRMEMFUNC_P (rhstype))
5620         rhs = cp_convert (strip_top_quals (type), rhs);
5621       else
5622         {
5623           /* If the right-hand side has unknown type, then it is an
5624              overloaded function.  Call instantiate_type to get error
5625              messages.  */
5626           if (rhstype == unknown_type_node)
5627             instantiate_type (type, rhs, tf_error | tf_warning);
5628           else if (fndecl)
5629             error ("cannot convert `%T' to `%T' for argument `%P' to `%D'",
5630                       rhstype, type, parmnum, fndecl);
5631           else
5632             error ("cannot convert `%T' to `%T' in %s", rhstype, type,
5633                       errtype);
5634           return error_mark_node;
5635         }
5636     }
5637   return perform_implicit_conversion (strip_top_quals (type), rhs);
5638 }
5639
5640 /* Convert RHS to be of type TYPE.
5641    If EXP is nonzero, it is the target of the initialization.
5642    ERRTYPE is a string to use in error messages.
5643
5644    Two major differences between the behavior of
5645    `convert_for_assignment' and `convert_for_initialization'
5646    are that references are bashed in the former, while
5647    copied in the latter, and aggregates are assigned in
5648    the former (operator=) while initialized in the
5649    latter (X(X&)).
5650
5651    If using constructor make sure no conversion operator exists, if one does
5652    exist, an ambiguity exists.
5653
5654    If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything.  */
5655
5656 tree
5657 convert_for_initialization (tree exp, tree type, tree rhs, int flags,
5658                             const char *errtype, tree fndecl, int parmnum)
5659 {
5660   register enum tree_code codel = TREE_CODE (type);
5661   register tree rhstype;
5662   register enum tree_code coder;
5663
5664   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5665      Strip such NOP_EXPRs, since RHS is used in non-lvalue context.  */
5666   if (TREE_CODE (rhs) == NOP_EXPR
5667       && TREE_TYPE (rhs) == TREE_TYPE (TREE_OPERAND (rhs, 0))
5668       && codel != REFERENCE_TYPE)
5669     rhs = TREE_OPERAND (rhs, 0);
5670
5671   if (rhs == error_mark_node
5672       || (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node))
5673     return error_mark_node;
5674
5675   if (TREE_CODE (TREE_TYPE (rhs)) == REFERENCE_TYPE)
5676     rhs = convert_from_reference (rhs);
5677
5678   if ((TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
5679        && TREE_CODE (type) != ARRAY_TYPE
5680        && (TREE_CODE (type) != REFERENCE_TYPE
5681            || TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE))
5682       || (TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE
5683           && (TREE_CODE (type) != REFERENCE_TYPE
5684               || TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE))
5685       || TREE_CODE (TREE_TYPE (rhs)) == METHOD_TYPE)
5686     rhs = decay_conversion (rhs);
5687
5688   rhstype = TREE_TYPE (rhs);
5689   coder = TREE_CODE (rhstype);
5690
5691   if (coder == ERROR_MARK)
5692     return error_mark_node;
5693
5694   /* We accept references to incomplete types, so we can
5695      return here before checking if RHS is of complete type.  */
5696
5697   if (codel == REFERENCE_TYPE)
5698     {
5699       /* This should eventually happen in convert_arguments.  */
5700       int savew = 0, savee = 0;
5701
5702       if (fndecl)
5703         savew = warningcount, savee = errorcount;
5704       rhs = initialize_reference (type, rhs, /*decl=*/NULL_TREE,
5705                                   /*cleanup=*/NULL);
5706       if (fndecl)
5707         {
5708           if (warningcount > savew)
5709             cp_warning_at ("in passing argument %P of `%+D'", parmnum, fndecl);
5710           else if (errorcount > savee)
5711             cp_error_at ("in passing argument %P of `%+D'", parmnum, fndecl);
5712         }
5713       return rhs;
5714     }
5715
5716   if (exp != 0)
5717     exp = require_complete_type (exp);
5718   if (exp == error_mark_node)
5719     return error_mark_node;
5720
5721   rhstype = non_reference (rhstype);
5722
5723   type = complete_type (type);
5724
5725   if (IS_AGGR_TYPE (type))
5726     return ocp_convert (type, rhs, CONV_IMPLICIT|CONV_FORCE_TEMP, flags);
5727
5728   return convert_for_assignment (type, rhs, errtype, fndecl, parmnum);
5729 }
5730 \f
5731 /* Expand an ASM statement with operands, handling output operands
5732    that are not variables or INDIRECT_REFS by transforming such
5733    cases into cases that expand_asm_operands can handle.
5734
5735    Arguments are same as for expand_asm_operands.
5736
5737    We don't do default conversions on all inputs, because it can screw
5738    up operands that are expected to be in memory.  */
5739
5740 void
5741 c_expand_asm_operands (tree string, tree outputs, tree inputs, tree clobbers,
5742                        int vol, const char *filename, int line)
5743 {
5744   int noutputs = list_length (outputs);
5745   register int i;
5746   /* o[I] is the place that output number I should be written.  */
5747   register tree *o = alloca (noutputs * sizeof (tree));
5748   register tree tail;
5749
5750   /* Record the contents of OUTPUTS before it is modified.  */
5751   for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
5752     o[i] = TREE_VALUE (tail);
5753
5754   /* Generate the ASM_OPERANDS insn;
5755      store into the TREE_VALUEs of OUTPUTS some trees for
5756      where the values were actually stored.  */
5757   expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line);
5758
5759   /* Copy all the intermediate outputs into the specified outputs.  */
5760   for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
5761     {
5762       if (o[i] != TREE_VALUE (tail))
5763         {
5764           expand_expr (build_modify_expr (o[i], NOP_EXPR, TREE_VALUE (tail)),
5765                        const0_rtx, VOIDmode, EXPAND_NORMAL);
5766           free_temp_slots ();
5767
5768           /* Restore the original value so that it's correct the next
5769              time we expand this function.  */
5770           TREE_VALUE (tail) = o[i];
5771         }
5772       /* Detect modification of read-only values.
5773          (Otherwise done by build_modify_expr.)  */
5774       else
5775         {
5776           tree type = TREE_TYPE (o[i]);
5777           if (type != error_mark_node
5778               && (CP_TYPE_CONST_P (type)
5779                   || (CLASS_TYPE_P (type) && C_TYPE_FIELDS_READONLY (type))))
5780             readonly_error (o[i], "modification by `asm'", 1);
5781         }
5782     }
5783
5784   /* Those MODIFY_EXPRs could do autoincrements.  */
5785   emit_queue ();
5786 }
5787 \f
5788 /* If RETVAL is the address of, or a reference to, a local variable or
5789    temporary give an appropriate warning.  */
5790
5791 static void
5792 maybe_warn_about_returning_address_of_local (tree retval)
5793 {
5794   tree valtype = TREE_TYPE (DECL_RESULT (current_function_decl));
5795   tree whats_returned = retval;
5796
5797   for (;;)
5798     {
5799       if (TREE_CODE (whats_returned) == COMPOUND_EXPR)
5800         whats_returned = TREE_OPERAND (whats_returned, 1);
5801       else if (TREE_CODE (whats_returned) == CONVERT_EXPR
5802                || TREE_CODE (whats_returned) == NON_LVALUE_EXPR
5803                || TREE_CODE (whats_returned) == NOP_EXPR)
5804         whats_returned = TREE_OPERAND (whats_returned, 0);
5805       else
5806         break;
5807     }
5808
5809   if (TREE_CODE (whats_returned) != ADDR_EXPR)
5810     return;
5811   whats_returned = TREE_OPERAND (whats_returned, 0);
5812
5813   if (TREE_CODE (valtype) == REFERENCE_TYPE)
5814     {
5815       if (TREE_CODE (whats_returned) == AGGR_INIT_EXPR
5816           || TREE_CODE (whats_returned) == TARGET_EXPR)
5817         {
5818           warning ("returning reference to temporary");
5819           return;
5820         }
5821       if (TREE_CODE (whats_returned) == VAR_DECL
5822           && DECL_NAME (whats_returned)
5823           && TEMP_NAME_P (DECL_NAME (whats_returned)))
5824         {
5825           warning ("reference to non-lvalue returned");
5826           return;
5827         }
5828     }
5829
5830   if (TREE_CODE (whats_returned) == VAR_DECL
5831       && DECL_NAME (whats_returned)
5832       && DECL_FUNCTION_SCOPE_P (whats_returned)
5833       && !(TREE_STATIC (whats_returned)
5834            || TREE_PUBLIC (whats_returned)))
5835     {
5836       if (TREE_CODE (valtype) == REFERENCE_TYPE)
5837         cp_warning_at ("reference to local variable `%D' returned",
5838                        whats_returned);
5839       else
5840         cp_warning_at ("address of local variable `%D' returned",
5841                        whats_returned);
5842       return;
5843     }
5844 }
5845
5846 /* Check that returning RETVAL from the current function is valid.
5847    Return an expression explicitly showing all conversions required to
5848    change RETVAL into the function return type, and to assign it to
5849    the DECL_RESULT for the function.  */
5850
5851 tree
5852 check_return_expr (tree retval)
5853 {
5854   tree result;
5855   /* The type actually returned by the function, after any
5856      promotions.  */
5857   tree valtype;
5858   int fn_returns_value_p;
5859
5860   /* A `volatile' function is one that isn't supposed to return, ever.
5861      (This is a G++ extension, used to get better code for functions
5862      that call the `volatile' function.)  */
5863   if (TREE_THIS_VOLATILE (current_function_decl))
5864     warning ("function declared `noreturn' has a `return' statement");
5865
5866   /* Check for various simple errors.  */
5867   if (DECL_DESTRUCTOR_P (current_function_decl))
5868     {
5869       if (retval)
5870         error ("returning a value from a destructor");
5871       return NULL_TREE;
5872     }
5873   else if (DECL_CONSTRUCTOR_P (current_function_decl))
5874     {
5875       if (in_function_try_handler)
5876         /* If a return statement appears in a handler of the
5877            function-try-block of a constructor, the program is ill-formed.  */
5878         error ("cannot return from a handler of a function-try-block of a constructor");
5879       else if (retval)
5880         /* You can't return a value from a constructor.  */
5881         error ("returning a value from a constructor");
5882       return NULL_TREE;
5883     }
5884
5885   if (processing_template_decl)
5886     {
5887       current_function_returns_value = 1;
5888       return retval;
5889     }
5890
5891   /* When no explicit return-value is given in a function with a named
5892      return value, the named return value is used.  */
5893   result = DECL_RESULT (current_function_decl);
5894   valtype = TREE_TYPE (result);
5895   my_friendly_assert (valtype != NULL_TREE, 19990924);
5896   fn_returns_value_p = !VOID_TYPE_P (valtype);
5897   if (!retval && DECL_NAME (result) && fn_returns_value_p)
5898     retval = result;
5899
5900   /* Check for a return statement with no return value in a function
5901      that's supposed to return a value.  */
5902   if (!retval && fn_returns_value_p)
5903     {
5904       pedwarn ("return-statement with no value, in function returning '%T'",
5905                valtype);
5906       /* Clear this, so finish_function won't say that we reach the
5907          end of a non-void function (which we don't, we gave a
5908          return!).  */
5909       current_function_returns_null = 0;
5910     }
5911   /* Check for a return statement with a value in a function that
5912      isn't supposed to return a value.  */
5913   else if (retval && !fn_returns_value_p)
5914     {
5915       if (VOID_TYPE_P (TREE_TYPE (retval)))
5916         /* You can return a `void' value from a function of `void'
5917            type.  In that case, we have to evaluate the expression for
5918            its side-effects.  */
5919           finish_expr_stmt (retval);
5920       else
5921         pedwarn ("return-statement with a value, in function "
5922                  "returning 'void'");
5923
5924       current_function_returns_null = 1;
5925
5926       /* There's really no value to return, after all.  */
5927       return NULL_TREE;
5928     }
5929   else if (!retval)
5930     /* Remember that this function can sometimes return without a
5931        value.  */
5932     current_function_returns_null = 1;
5933   else
5934     /* Remember that this function did return a value.  */
5935     current_function_returns_value = 1;
5936
5937   /* Only operator new(...) throw(), can return NULL [expr.new/13].  */
5938   if ((DECL_OVERLOADED_OPERATOR_P (current_function_decl) == NEW_EXPR
5939        || DECL_OVERLOADED_OPERATOR_P (current_function_decl) == VEC_NEW_EXPR)
5940       && !TYPE_NOTHROW_P (TREE_TYPE (current_function_decl))
5941       && ! flag_check_new
5942       && null_ptr_cst_p (retval))
5943     warning ("`operator new' must not return NULL unless it is declared `throw()' (or -fcheck-new is in effect)");
5944
5945   /* Effective C++ rule 15.  See also start_function.  */
5946   if (warn_ecpp
5947       && DECL_NAME (current_function_decl) == ansi_assopname(NOP_EXPR)
5948       && retval != current_class_ref)
5949     warning ("`operator=' should return a reference to `*this'");
5950
5951   /* The fabled Named Return Value optimization, as per [class.copy]/15:
5952
5953      [...]      For  a function with a class return type, if the expression
5954      in the return statement is the name of a local  object,  and  the  cv-
5955      unqualified  type  of  the  local  object  is the same as the function
5956      return type, an implementation is permitted to omit creating the  tem-
5957      porary  object  to  hold  the function return value [...]
5958
5959      So, if this is a value-returning function that always returns the same
5960      local variable, remember it.
5961
5962      It might be nice to be more flexible, and choose the first suitable
5963      variable even if the function sometimes returns something else, but
5964      then we run the risk of clobbering the variable we chose if the other
5965      returned expression uses the chosen variable somehow.  And people expect
5966      this restriction, anyway.  (jason 2000-11-19)
5967
5968      See finish_function, genrtl_start_function, and declare_return_variable
5969      for other pieces of this optimization.  */
5970
5971   if (fn_returns_value_p && flag_elide_constructors)
5972     {
5973       if (retval != NULL_TREE
5974           && (current_function_return_value == NULL_TREE
5975               || current_function_return_value == retval)
5976           && TREE_CODE (retval) == VAR_DECL
5977           && DECL_CONTEXT (retval) == current_function_decl
5978           && ! TREE_STATIC (retval)
5979           && (DECL_ALIGN (retval)
5980               >= DECL_ALIGN (DECL_RESULT (current_function_decl)))
5981           && same_type_p ((TYPE_MAIN_VARIANT
5982                            (TREE_TYPE (retval))),
5983                           (TYPE_MAIN_VARIANT
5984                            (TREE_TYPE (TREE_TYPE (current_function_decl))))))
5985         current_function_return_value = retval;
5986       else
5987         current_function_return_value = error_mark_node;
5988     }
5989
5990   /* We don't need to do any conversions when there's nothing being
5991      returned.  */
5992   if (!retval || retval == error_mark_node)
5993     return retval;
5994
5995   /* Do any required conversions.  */
5996   if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl))
5997     /* No conversions are required.  */
5998     ;
5999   else
6000     {
6001       /* The type the function is declared to return.  */
6002       tree functype = TREE_TYPE (TREE_TYPE (current_function_decl));
6003
6004       /* First convert the value to the function's return type, then
6005          to the type of return value's location to handle the
6006          case that functype is smaller than the valtype.  */
6007       retval = convert_for_initialization
6008         (NULL_TREE, functype, retval, LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING,
6009          "return", NULL_TREE, 0);
6010       retval = convert (valtype, retval);
6011
6012       /* If the conversion failed, treat this just like `return;'.  */
6013       if (retval == error_mark_node)
6014         return retval;
6015       /* We can't initialize a register from a AGGR_INIT_EXPR.  */
6016       else if (! current_function_returns_struct
6017                && TREE_CODE (retval) == TARGET_EXPR
6018                && TREE_CODE (TREE_OPERAND (retval, 1)) == AGGR_INIT_EXPR)
6019         retval = build (COMPOUND_EXPR, TREE_TYPE (retval), retval,
6020                         TREE_OPERAND (retval, 0));
6021       else
6022         maybe_warn_about_returning_address_of_local (retval);
6023     }
6024
6025   /* Actually copy the value returned into the appropriate location.  */
6026   if (retval && retval != result)
6027     retval = build (INIT_EXPR, TREE_TYPE (result), result, retval);
6028
6029   return retval;
6030 }
6031
6032 \f
6033 /* Returns nonzero if the pointer-type FROM can be converted to the
6034    pointer-type TO via a qualification conversion.  If CONSTP is -1,
6035    then we return nonzero if the pointers are similar, and the
6036    cv-qualification signature of FROM is a proper subset of that of TO.
6037
6038    If CONSTP is positive, then all outer pointers have been
6039    const-qualified.  */
6040
6041 static int
6042 comp_ptr_ttypes_real (tree to, tree from, int constp)
6043 {
6044   bool to_more_cv_qualified = false;
6045
6046   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6047     {
6048       if (TREE_CODE (to) != TREE_CODE (from))
6049         return 0;
6050
6051       if (TREE_CODE (from) == OFFSET_TYPE
6052           && !same_type_p (TYPE_OFFSET_BASETYPE (from),
6053                            TYPE_OFFSET_BASETYPE (to)))
6054         return 0;
6055
6056       /* Const and volatile mean something different for function types,
6057          so the usual checks are not appropriate.  */
6058       if (TREE_CODE (to) != FUNCTION_TYPE && TREE_CODE (to) != METHOD_TYPE)
6059         {
6060           if (!at_least_as_qualified_p (to, from))
6061             return 0;
6062
6063           if (!at_least_as_qualified_p (from, to))
6064             {
6065               if (constp == 0)
6066                 return 0;
6067               to_more_cv_qualified = true;
6068             }
6069
6070           if (constp > 0)
6071             constp &= TYPE_READONLY (to);
6072         }
6073
6074       if (TREE_CODE (to) != POINTER_TYPE && !TYPE_PTRMEM_P (to))
6075         return ((constp >= 0 || to_more_cv_qualified)
6076                 && same_type_ignoring_top_level_qualifiers_p (to, from));
6077     }
6078 }
6079
6080 /* When comparing, say, char ** to char const **, this function takes
6081    the 'char *' and 'char const *'.  Do not pass non-pointer/reference
6082    types to this function.  */
6083
6084 int
6085 comp_ptr_ttypes (tree to, tree from)
6086 {
6087   return comp_ptr_ttypes_real (to, from, 1);
6088 }
6089
6090 /* Returns 1 if to and from are (possibly multi-level) pointers to the same
6091    type or inheritance-related types, regardless of cv-quals.  */
6092
6093 int
6094 ptr_reasonably_similar (tree to, tree from)
6095 {
6096   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6097     {
6098       /* Any target type is similar enough to void.  */
6099       if (TREE_CODE (to) == VOID_TYPE
6100           || TREE_CODE (from) == VOID_TYPE)
6101         return 1;
6102
6103       if (TREE_CODE (to) != TREE_CODE (from))
6104         return 0;
6105
6106       if (TREE_CODE (from) == OFFSET_TYPE
6107           && comptypes (TYPE_OFFSET_BASETYPE (to),
6108                         TYPE_OFFSET_BASETYPE (from),
6109                         COMPARE_BASE | COMPARE_DERIVED))
6110         continue;
6111
6112       if (TREE_CODE (to) == INTEGER_TYPE
6113           && TYPE_PRECISION (to) == TYPE_PRECISION (from))
6114         return 1;
6115
6116       if (TREE_CODE (to) == FUNCTION_TYPE)
6117         return 1;
6118
6119       if (TREE_CODE (to) != POINTER_TYPE)
6120         return comptypes
6121           (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from),
6122            COMPARE_BASE | COMPARE_DERIVED);
6123     }
6124 }
6125
6126 /* Like comp_ptr_ttypes, for const_cast.  */
6127
6128 static int
6129 comp_ptr_ttypes_const (tree to, tree from)
6130 {
6131   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6132     {
6133       if (TREE_CODE (to) != TREE_CODE (from))
6134         return 0;
6135
6136       if (TREE_CODE (from) == OFFSET_TYPE
6137           && same_type_p (TYPE_OFFSET_BASETYPE (from),
6138                           TYPE_OFFSET_BASETYPE (to)))
6139           continue;
6140
6141       if (TREE_CODE (to) != POINTER_TYPE)
6142         return same_type_ignoring_top_level_qualifiers_p (to, from);
6143     }
6144 }
6145
6146 /* Returns the type qualifiers for this type, including the qualifiers on the
6147    elements for an array type.  */
6148
6149 int
6150 cp_type_quals (tree type)
6151 {
6152   type = strip_array_types (type);
6153   if (type == error_mark_node)
6154     return TYPE_UNQUALIFIED;
6155   return TYPE_QUALS (type);
6156 }
6157
6158 /* Returns nonzero if the TYPE contains a mutable member */
6159
6160 bool
6161 cp_has_mutable_p (tree type)
6162 {
6163   type = strip_array_types (type);
6164
6165   return CLASS_TYPE_P (type) && CLASSTYPE_HAS_MUTABLE (type);
6166 }
6167
6168 /* Subroutine of casts_away_constness.  Make T1 and T2 point at
6169    exemplar types such that casting T1 to T2 is casting away castness
6170    if and only if there is no implicit conversion from T1 to T2.  */
6171
6172 static void
6173 casts_away_constness_r (tree *t1, tree *t2)
6174 {
6175   int quals1;
6176   int quals2;
6177
6178   /* [expr.const.cast]
6179
6180      For multi-level pointer to members and multi-level mixed pointers
6181      and pointers to members (conv.qual), the "member" aspect of a
6182      pointer to member level is ignored when determining if a const
6183      cv-qualifier has been cast away.  */
6184   if (TYPE_PTRMEM_P (*t1))
6185     *t1 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t1));
6186   if (TYPE_PTRMEM_P (*t2))
6187     *t2 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t2));
6188
6189   /* [expr.const.cast]
6190
6191      For  two  pointer types:
6192
6193             X1 is T1cv1,1 * ... cv1,N *   where T1 is not a pointer type
6194             X2 is T2cv2,1 * ... cv2,M *   where T2 is not a pointer type
6195             K is min(N,M)
6196
6197      casting from X1 to X2 casts away constness if, for a non-pointer
6198      type T there does not exist an implicit conversion (clause
6199      _conv_) from:
6200
6201             Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N *
6202
6203      to
6204
6205             Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *.  */
6206
6207   if (TREE_CODE (*t1) != POINTER_TYPE
6208       || TREE_CODE (*t2) != POINTER_TYPE)
6209     {
6210       *t1 = cp_build_qualified_type (void_type_node,
6211                                      cp_type_quals (*t1));
6212       *t2 = cp_build_qualified_type (void_type_node,
6213                                      cp_type_quals (*t2));
6214       return;
6215     }
6216
6217   quals1 = cp_type_quals (*t1);
6218   quals2 = cp_type_quals (*t2);
6219   *t1 = TREE_TYPE (*t1);
6220   *t2 = TREE_TYPE (*t2);
6221   casts_away_constness_r (t1, t2);
6222   *t1 = build_pointer_type (*t1);
6223   *t2 = build_pointer_type (*t2);
6224   *t1 = cp_build_qualified_type (*t1, quals1);
6225   *t2 = cp_build_qualified_type (*t2, quals2);
6226 }
6227
6228 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
6229    constness.  */
6230
6231 static bool
6232 casts_away_constness (tree t1, tree t2)
6233 {
6234   if (TREE_CODE (t2) == REFERENCE_TYPE)
6235     {
6236       /* [expr.const.cast]
6237
6238          Casting from an lvalue of type T1 to an lvalue of type T2
6239          using a reference cast casts away constness if a cast from an
6240          rvalue of type "pointer to T1" to the type "pointer to T2"
6241          casts away constness.  */
6242       t1 = (TREE_CODE (t1) == REFERENCE_TYPE ? TREE_TYPE (t1) : t1);
6243       return casts_away_constness (build_pointer_type (t1),
6244                                    build_pointer_type (TREE_TYPE (t2)));
6245     }
6246
6247   if (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2))
6248     /* [expr.const.cast]
6249
6250        Casting from an rvalue of type "pointer to data member of X
6251        of type T1" to the type "pointer to data member of Y of type
6252        T2" casts away constness if a cast from an rvalue of type
6253        "pointer to T1" to the type "pointer to T2" casts away
6254        constness.  */
6255     return casts_away_constness
6256       (build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t1)),
6257        build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t2)));
6258
6259   /* Casting away constness is only something that makes sense for
6260      pointer or reference types.  */
6261   if (TREE_CODE (t1) != POINTER_TYPE
6262       || TREE_CODE (t2) != POINTER_TYPE)
6263     return false;
6264
6265   /* Top-level qualifiers don't matter.  */
6266   t1 = TYPE_MAIN_VARIANT (t1);
6267   t2 = TYPE_MAIN_VARIANT (t2);
6268   casts_away_constness_r (&t1, &t2);
6269   if (!can_convert (t2, t1))
6270     return true;
6271
6272   return false;
6273 }
6274
6275 /* If T is a REFERENCE_TYPE return the type to which T refers.
6276    Otherwise, return T itself.  */
6277
6278 tree
6279 non_reference (tree t)
6280 {
6281   if (TREE_CODE (t) == REFERENCE_TYPE)
6282     t = TREE_TYPE (t);
6283   return t;
6284 }