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, build_pointer_type (TREE_TYPE (t)), t);
3585   if (staticp (t))
3586     TREE_CONSTANT (addr) = 1;
3587
3588   return addr;
3589 }
3590
3591 /* Return a NOP_EXPR converting EXPR to TYPE.  */
3592
3593 tree
3594 build_nop (tree type, tree expr)
3595 {
3596   tree nop;
3597
3598   if (type == error_mark_node || error_operand_p (expr))
3599     return expr;
3600
3601   nop = build1 (NOP_EXPR, type, expr);
3602   if (TREE_CONSTANT (expr))
3603     TREE_CONSTANT (nop) = 1;
3604
3605   return nop;
3606 }
3607
3608 /* C++: Must handle pointers to members.
3609
3610    Perhaps type instantiation should be extended to handle conversion
3611    from aggregates to types we don't yet know we want?  (Or are those
3612    cases typically errors which should be reported?)
3613
3614    NOCONVERT nonzero suppresses the default promotions
3615    (such as from short to int).  */
3616
3617 tree
3618 build_unary_op (enum tree_code code, tree xarg, int noconvert)
3619 {
3620   /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
3621   register tree arg = xarg;
3622   register tree argtype = 0;
3623   const char *errstring = NULL;
3624   tree val;
3625
3626   if (arg == error_mark_node)
3627     return error_mark_node;
3628
3629   switch (code)
3630     {
3631     case CONVERT_EXPR:
3632       /* This is used for unary plus, because a CONVERT_EXPR
3633          is enough to prevent anybody from looking inside for
3634          associativity, but won't generate any code.  */
3635       if (!(arg = build_expr_type_conversion
3636             (WANT_ARITH | WANT_ENUM | WANT_POINTER, arg, true)))
3637         errstring = "wrong type argument to unary plus";
3638       else
3639         {
3640           if (!noconvert)
3641            arg = default_conversion (arg);
3642           arg = build1 (NON_LVALUE_EXPR, TREE_TYPE (arg), arg);
3643           TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3644         }
3645       break;
3646
3647     case NEGATE_EXPR:
3648       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3649         errstring = "wrong type argument to unary minus";
3650       else if (!noconvert && CP_INTEGRAL_TYPE_P (TREE_TYPE (arg)))
3651         arg = perform_integral_promotions (arg);
3652       break;
3653
3654     case BIT_NOT_EXPR:
3655       if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3656         {
3657           code = CONJ_EXPR;
3658           if (!noconvert)
3659             arg = default_conversion (arg);
3660         }
3661       else if (!(arg = build_expr_type_conversion (WANT_INT | WANT_ENUM,
3662                                                    arg, true)))
3663         errstring = "wrong type argument to bit-complement";
3664       else if (!noconvert)
3665         arg = perform_integral_promotions (arg);
3666       break;
3667
3668     case ABS_EXPR:
3669       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3670         errstring = "wrong type argument to abs";
3671       else if (!noconvert)
3672         arg = default_conversion (arg);
3673       break;
3674
3675     case CONJ_EXPR:
3676       /* Conjugating a real value is a no-op, but allow it anyway.  */
3677       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, arg, true)))
3678         errstring = "wrong type argument to conjugation";
3679       else if (!noconvert)
3680         arg = default_conversion (arg);
3681       break;
3682
3683     case TRUTH_NOT_EXPR:
3684       arg = perform_implicit_conversion (boolean_type_node, arg);
3685       val = invert_truthvalue (arg);
3686       if (arg != error_mark_node)
3687         return val;
3688       errstring = "in argument to unary !";
3689       break;
3690
3691     case NOP_EXPR:
3692       break;
3693
3694     case REALPART_EXPR:
3695       if (TREE_CODE (arg) == COMPLEX_CST)
3696         return TREE_REALPART (arg);
3697       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3698         return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
3699       else
3700         return arg;
3701
3702     case IMAGPART_EXPR:
3703       if (TREE_CODE (arg) == COMPLEX_CST)
3704         return TREE_IMAGPART (arg);
3705       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3706         return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
3707       else
3708         return cp_convert (TREE_TYPE (arg), integer_zero_node);
3709
3710     case PREINCREMENT_EXPR:
3711     case POSTINCREMENT_EXPR:
3712     case PREDECREMENT_EXPR:
3713     case POSTDECREMENT_EXPR:
3714       /* Handle complex lvalues (when permitted)
3715          by reduction to simpler cases.  */
3716
3717       val = unary_complex_lvalue (code, arg);
3718       if (val != 0)
3719         return val;
3720
3721       /* Increment or decrement the real part of the value,
3722          and don't change the imaginary part.  */
3723       if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
3724         {
3725           tree real, imag;
3726
3727           arg = stabilize_reference (arg);
3728           real = build_unary_op (REALPART_EXPR, arg, 1);
3729           imag = build_unary_op (IMAGPART_EXPR, arg, 1);
3730           return build (COMPLEX_EXPR, TREE_TYPE (arg),
3731                         build_unary_op (code, real, 1), imag);
3732         }
3733
3734       /* Report invalid types.  */
3735
3736       if (!(arg = build_expr_type_conversion (WANT_ARITH | WANT_POINTER,
3737                                               arg, true)))
3738         {
3739           if (code == PREINCREMENT_EXPR)
3740             errstring ="no pre-increment operator for type";
3741           else if (code == POSTINCREMENT_EXPR)
3742             errstring ="no post-increment operator for type";
3743           else if (code == PREDECREMENT_EXPR)
3744             errstring ="no pre-decrement operator for type";
3745           else
3746             errstring ="no post-decrement operator for type";
3747           break;
3748         }
3749
3750       /* Report something read-only.  */
3751
3752       if (CP_TYPE_CONST_P (TREE_TYPE (arg))
3753           || TREE_READONLY (arg))
3754         readonly_error (arg, ((code == PREINCREMENT_EXPR
3755                                || code == POSTINCREMENT_EXPR)
3756                               ? "increment" : "decrement"),
3757                         0);
3758
3759       {
3760         register tree inc;
3761         tree result_type = TREE_TYPE (arg);
3762
3763         arg = get_unwidened (arg, 0);
3764         argtype = TREE_TYPE (arg);
3765
3766         /* ARM $5.2.5 last annotation says this should be forbidden.  */
3767         if (TREE_CODE (argtype) == ENUMERAL_TYPE)
3768           pedwarn ("ISO C++ forbids %sing an enum",
3769                    (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
3770                    ? "increment" : "decrement");
3771
3772         /* Compute the increment.  */
3773
3774         if (TREE_CODE (argtype) == POINTER_TYPE)
3775           {
3776             tree type = complete_type (TREE_TYPE (argtype));
3777
3778             if (!COMPLETE_OR_VOID_TYPE_P (type))
3779               error ("cannot %s a pointer to incomplete type `%T'",
3780                         ((code == PREINCREMENT_EXPR
3781                           || code == POSTINCREMENT_EXPR)
3782                          ? "increment" : "decrement"), TREE_TYPE (argtype));
3783             else if ((pedantic || warn_pointer_arith)
3784                      && !TYPE_PTROB_P (argtype))
3785               pedwarn ("ISO C++ forbids %sing a pointer of type `%T'",
3786                           ((code == PREINCREMENT_EXPR
3787                             || code == POSTINCREMENT_EXPR)
3788                            ? "increment" : "decrement"), argtype);
3789             inc = cxx_sizeof_nowarn (TREE_TYPE (argtype));
3790           }
3791         else
3792           inc = integer_one_node;
3793
3794         inc = cp_convert (argtype, inc);
3795
3796         /* Handle incrementing a cast-expression.  */
3797
3798         switch (TREE_CODE (arg))
3799           {
3800           case NOP_EXPR:
3801           case CONVERT_EXPR:
3802           case FLOAT_EXPR:
3803           case FIX_TRUNC_EXPR:
3804           case FIX_FLOOR_EXPR:
3805           case FIX_ROUND_EXPR:
3806           case FIX_CEIL_EXPR:
3807             {
3808               tree incremented, modify, value, compound;
3809               if (! lvalue_p (arg) && pedantic)
3810                 pedwarn ("cast to non-reference type used as lvalue");
3811               arg = stabilize_reference (arg);
3812               if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR)
3813                 value = arg;
3814               else
3815                 value = save_expr (arg);
3816               incremented = build (((code == PREINCREMENT_EXPR
3817                                      || code == POSTINCREMENT_EXPR)
3818                                     ? PLUS_EXPR : MINUS_EXPR),
3819                                    argtype, value, inc);
3820
3821               modify = build_modify_expr (arg, NOP_EXPR, incremented);
3822               compound = build (COMPOUND_EXPR, TREE_TYPE (arg), modify, value);
3823
3824               /* Eliminate warning about unused result of + or -.  */
3825               TREE_NO_UNUSED_WARNING (compound) = 1;
3826               return compound;
3827             }
3828
3829           default:
3830             break;
3831           }
3832
3833         /* Complain about anything else that is not a true lvalue.  */
3834         if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
3835                                     || code == POSTINCREMENT_EXPR)
3836                                    ? "increment" : "decrement")))
3837           return error_mark_node;
3838
3839         /* Forbid using -- on `bool'.  */
3840         if (TREE_TYPE (arg) == boolean_type_node)
3841           {
3842             if (code == POSTDECREMENT_EXPR || code == PREDECREMENT_EXPR)
3843               {
3844                 error ("invalid use of `--' on bool variable `%D'", arg);
3845                 return error_mark_node;
3846               }
3847             val = boolean_increment (code, arg);
3848           }
3849         else
3850           val = build (code, TREE_TYPE (arg), arg, inc);
3851
3852         TREE_SIDE_EFFECTS (val) = 1;
3853         return cp_convert (result_type, val);
3854       }
3855
3856     case ADDR_EXPR:
3857       /* Note that this operation never does default_conversion
3858          regardless of NOCONVERT.  */
3859
3860       argtype = lvalue_type (arg);
3861
3862       if (TREE_CODE (arg) == OFFSET_REF)
3863         goto offset_ref;
3864
3865       if (TREE_CODE (argtype) == REFERENCE_TYPE)
3866         {
3867           arg = build1
3868             (CONVERT_EXPR,
3869              build_pointer_type (TREE_TYPE (argtype)), arg);
3870           TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3871           return arg;
3872         }
3873       else if (pedantic && DECL_MAIN_P (arg))
3874         /* ARM $3.4 */
3875         pedwarn ("ISO C++ forbids taking address of function `::main'");
3876
3877       /* Let &* cancel out to simplify resulting code.  */
3878       if (TREE_CODE (arg) == INDIRECT_REF)
3879         {
3880           /* We don't need to have `current_class_ptr' wrapped in a
3881              NON_LVALUE_EXPR node.  */
3882           if (arg == current_class_ref)
3883             return current_class_ptr;
3884
3885           arg = TREE_OPERAND (arg, 0);
3886           if (TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE)
3887             {
3888               arg = build1
3889                 (CONVERT_EXPR,
3890                  build_pointer_type (TREE_TYPE (TREE_TYPE (arg))), arg);
3891               TREE_CONSTANT (arg) = TREE_CONSTANT (TREE_OPERAND (arg, 0));
3892             }
3893           else if (lvalue_p (arg))
3894             /* Don't let this be an lvalue.  */
3895             return non_lvalue (arg);
3896           return arg;
3897         }
3898
3899       /* For &x[y], return x+y */
3900       if (TREE_CODE (arg) == ARRAY_REF)
3901         {
3902           if (!cxx_mark_addressable (TREE_OPERAND (arg, 0)))
3903             return error_mark_node;
3904           return cp_build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
3905                                      TREE_OPERAND (arg, 1));
3906         }
3907
3908       /* Uninstantiated types are all functions.  Taking the
3909          address of a function is a no-op, so just return the
3910          argument.  */
3911
3912       if (TREE_CODE (arg) == IDENTIFIER_NODE
3913           && IDENTIFIER_OPNAME_P (arg))
3914         {
3915           abort ();
3916           /* We don't know the type yet, so just work around the problem.
3917              We know that this will resolve to an lvalue.  */
3918           return build1 (ADDR_EXPR, unknown_type_node, arg);
3919         }
3920
3921       if (TREE_CODE (arg) == COMPONENT_REF && type_unknown_p (arg)
3922           && !really_overloaded_fn (TREE_OPERAND (arg, 1)))
3923         {
3924           /* They're trying to take the address of a unique non-static
3925              member function.  This is ill-formed (except in MS-land),
3926              but let's try to DTRT.
3927              Note: We only handle unique functions here because we don't
3928              want to complain if there's a static overload; non-unique
3929              cases will be handled by instantiate_type.  But we need to
3930              handle this case here to allow casts on the resulting PMF.
3931              We could defer this in non-MS mode, but it's easier to give
3932              a useful error here.  */
3933
3934           /* Inside constant member functions, the `this' pointer
3935              contains an extra const qualifier.  TYPE_MAIN_VARIANT
3936              is used here to remove this const from the diagnostics
3937              and the created OFFSET_REF.  */
3938           tree base = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (arg, 0)));
3939           tree name = DECL_NAME (get_first_fn (TREE_OPERAND (arg, 1)));
3940
3941           if (! flag_ms_extensions)
3942             {
3943               if (current_class_type
3944                   && TREE_OPERAND (arg, 0) == current_class_ref)
3945                 /* An expression like &memfn.  */
3946                 pedwarn ("ISO C++ forbids taking the address of an unqualified"
3947                          " or parenthesized non-static member function to form"
3948                          " a pointer to member function.  Say `&%T::%D'",
3949                          base, name);
3950               else
3951                 pedwarn ("ISO C++ forbids taking the address of a bound member"
3952                          " function to form a pointer to member function."
3953                          "  Say `&%T::%D'",
3954                          base, name);
3955             }
3956           arg = build_offset_ref (base, name, /*address_p=*/true);
3957         }
3958
3959     offset_ref:
3960       if (type_unknown_p (arg))
3961         return build1 (ADDR_EXPR, unknown_type_node, arg);
3962
3963       /* Handle complex lvalues (when permitted)
3964          by reduction to simpler cases.  */
3965       val = unary_complex_lvalue (code, arg);
3966       if (val != 0)
3967         return val;
3968
3969       switch (TREE_CODE (arg))
3970         {
3971         case NOP_EXPR:
3972         case CONVERT_EXPR:
3973         case FLOAT_EXPR:
3974         case FIX_TRUNC_EXPR:
3975         case FIX_FLOOR_EXPR:
3976         case FIX_ROUND_EXPR:
3977         case FIX_CEIL_EXPR:
3978           if (! lvalue_p (arg) && pedantic)
3979             pedwarn ("ISO C++ forbids taking the address of a cast to a non-lvalue expression");
3980           break;
3981
3982         default:
3983           break;
3984         }
3985
3986       /* Allow the address of a constructor if all the elements
3987          are constant.  */
3988       if (TREE_CODE (arg) == CONSTRUCTOR && TREE_HAS_CONSTRUCTOR (arg)
3989           && TREE_CONSTANT (arg))
3990         ;
3991       /* Anything not already handled and not a true memory reference
3992          is an error.  */
3993       else if (TREE_CODE (argtype) != FUNCTION_TYPE
3994                && TREE_CODE (argtype) != METHOD_TYPE
3995                && !lvalue_or_else (arg, "unary `&'"))
3996         return error_mark_node;
3997
3998       if (argtype != error_mark_node)
3999         argtype = build_pointer_type (argtype);
4000
4001       {
4002         tree addr;
4003
4004         if (TREE_CODE (arg) != COMPONENT_REF)
4005           addr = build_address (arg);
4006         else if (TREE_CODE (TREE_OPERAND (arg, 1)) == BASELINK)
4007           {
4008             tree fn = BASELINK_FUNCTIONS (TREE_OPERAND (arg, 1));
4009
4010             /* We can only get here with a single static member
4011                function.  */
4012             my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL
4013                                 && DECL_STATIC_FUNCTION_P (fn),
4014                                 20030906);
4015             mark_used (fn);
4016             addr = build_address (fn);
4017             if (TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0)))
4018               /* Do not lose object's side effects.  */
4019               addr = build (COMPOUND_EXPR, TREE_TYPE (addr),
4020                             TREE_OPERAND (arg, 0), addr);
4021           }
4022         else if (DECL_C_BIT_FIELD (TREE_OPERAND (arg, 1)))
4023           {
4024             error ("attempt to take address of bit-field structure member `%D'",
4025                    TREE_OPERAND (arg, 1));
4026             return error_mark_node;
4027           }
4028         else
4029           {
4030             /* Unfortunately we cannot just build an address
4031                expression here, because we would not handle
4032                address-constant-expressions or offsetof correctly.  */
4033             tree field = TREE_OPERAND (arg, 1);
4034             tree rval = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), 0);
4035             tree binfo = lookup_base (TREE_TYPE (TREE_TYPE (rval)),
4036                                       decl_type_context (field),
4037                                       ba_check, NULL);
4038
4039             rval = build_base_path (PLUS_EXPR, rval, binfo, 1);
4040             rval = build_nop (argtype, rval);
4041             addr = fold (build (PLUS_EXPR, argtype, rval,
4042                                 cp_convert (argtype, byte_position (field))));
4043           }
4044
4045         if (TREE_CODE (argtype) == POINTER_TYPE
4046             && TREE_CODE (TREE_TYPE (argtype)) == METHOD_TYPE)
4047           {
4048             build_ptrmemfunc_type (argtype);
4049             addr = build_ptrmemfunc (argtype, addr, 0);
4050           }
4051
4052         return addr;
4053       }
4054
4055     default:
4056       break;
4057     }
4058
4059   if (!errstring)
4060     {
4061       if (argtype == 0)
4062         argtype = TREE_TYPE (arg);
4063       return fold (build1 (code, argtype, arg));
4064     }
4065
4066   error ("%s", errstring);
4067   return error_mark_node;
4068 }
4069
4070 /* Apply unary lvalue-demanding operator CODE to the expression ARG
4071    for certain kinds of expressions which are not really lvalues
4072    but which we can accept as lvalues.
4073
4074    If ARG is not a kind of expression we can handle, return zero.  */
4075
4076 tree
4077 unary_complex_lvalue (enum tree_code code, tree arg)
4078 {
4079   /* Handle (a, b) used as an "lvalue".  */
4080   if (TREE_CODE (arg) == COMPOUND_EXPR)
4081     {
4082       tree real_result = build_unary_op (code, TREE_OPERAND (arg, 1), 0);
4083       return build (COMPOUND_EXPR, TREE_TYPE (real_result),
4084                     TREE_OPERAND (arg, 0), real_result);
4085     }
4086
4087   /* Handle (a ? b : c) used as an "lvalue".  */
4088   if (TREE_CODE (arg) == COND_EXPR
4089       || TREE_CODE (arg) == MIN_EXPR || TREE_CODE (arg) == MAX_EXPR)
4090     return rationalize_conditional_expr (code, arg);
4091
4092   /* Handle (a = b), (++a), and (--a) used as an "lvalue".  */
4093   if (TREE_CODE (arg) == MODIFY_EXPR
4094       || TREE_CODE (arg) == PREINCREMENT_EXPR
4095       || TREE_CODE (arg) == PREDECREMENT_EXPR)
4096     {
4097       tree lvalue = TREE_OPERAND (arg, 0);
4098       if (TREE_SIDE_EFFECTS (lvalue))
4099         {
4100           lvalue = stabilize_reference (lvalue);
4101           arg = build (TREE_CODE (arg), TREE_TYPE (arg),
4102                        lvalue, TREE_OPERAND (arg, 1));
4103         }
4104       return unary_complex_lvalue
4105         (code, build (COMPOUND_EXPR, TREE_TYPE (lvalue), arg, lvalue));
4106     }
4107
4108   if (code != ADDR_EXPR)
4109     return 0;
4110
4111   /* Handle (a = b) used as an "lvalue" for `&'.  */
4112   if (TREE_CODE (arg) == MODIFY_EXPR
4113       || TREE_CODE (arg) == INIT_EXPR)
4114     {
4115       tree real_result = build_unary_op (code, TREE_OPERAND (arg, 0), 0);
4116       arg = build (COMPOUND_EXPR, TREE_TYPE (real_result), arg, real_result);
4117       TREE_NO_UNUSED_WARNING (arg) = 1;
4118       return arg;
4119     }
4120
4121   if (TREE_CODE (TREE_TYPE (arg)) == FUNCTION_TYPE
4122       || TREE_CODE (TREE_TYPE (arg)) == METHOD_TYPE
4123       || TREE_CODE (arg) == OFFSET_REF)
4124     {
4125       tree t;
4126
4127       my_friendly_assert (TREE_CODE (arg) != SCOPE_REF, 313);
4128
4129       if (TREE_CODE (arg) != OFFSET_REF)
4130         return 0;
4131
4132       t = TREE_OPERAND (arg, 1);
4133
4134       /* Check all this code for right semantics.  */
4135       if (TREE_CODE (t) == FUNCTION_DECL)
4136         {
4137           if (DECL_DESTRUCTOR_P (t))
4138             error ("taking address of destructor");
4139           return build_unary_op (ADDR_EXPR, t, 0);
4140         }
4141       if (TREE_CODE (t) == VAR_DECL)
4142         return build_unary_op (ADDR_EXPR, t, 0);
4143       else
4144         {
4145           tree type;
4146
4147           if (TREE_OPERAND (arg, 0)
4148               && ! is_dummy_object (TREE_OPERAND (arg, 0))
4149               && TREE_CODE (t) != FIELD_DECL)
4150             {
4151               error ("taking address of bound pointer-to-member expression");
4152               return error_mark_node;
4153             }
4154           if (!PTRMEM_OK_P (arg))
4155             return build_unary_op (code, arg, 0);
4156
4157           if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE)
4158             {
4159               error ("cannot create pointer to reference member `%D'", t);
4160               return error_mark_node;
4161             }
4162
4163           type = build_ptrmem_type (DECL_FIELD_CONTEXT (t), TREE_TYPE (t));
4164           t = make_ptrmem_cst (type, TREE_OPERAND (arg, 1));
4165           return t;
4166         }
4167     }
4168
4169
4170   /* We permit compiler to make function calls returning
4171      objects of aggregate type look like lvalues.  */
4172   {
4173     tree targ = arg;
4174
4175     if (TREE_CODE (targ) == SAVE_EXPR)
4176       targ = TREE_OPERAND (targ, 0);
4177
4178     if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (TREE_TYPE (targ)))
4179       {
4180         if (TREE_CODE (arg) == SAVE_EXPR)
4181           targ = arg;
4182         else
4183           targ = build_cplus_new (TREE_TYPE (arg), arg);
4184         return build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (arg)), targ);
4185       }
4186
4187     if (TREE_CODE (arg) == SAVE_EXPR && TREE_CODE (targ) == INDIRECT_REF)
4188       return build (SAVE_EXPR, build_pointer_type (TREE_TYPE (arg)),
4189                      TREE_OPERAND (targ, 0), current_function_decl, NULL);
4190   }
4191
4192   /* Don't let anything else be handled specially.  */
4193   return 0;
4194 }
4195 \f
4196 /* Mark EXP saying that we need to be able to take the
4197    address of it; it should not be allocated in a register.
4198    Value is true if successful.
4199
4200    C++: we do not allow `current_class_ptr' to be addressable.  */
4201
4202 bool
4203 cxx_mark_addressable (tree exp)
4204 {
4205   register tree x = exp;
4206
4207   while (1)
4208     switch (TREE_CODE (x))
4209       {
4210       case ADDR_EXPR:
4211       case COMPONENT_REF:
4212       case ARRAY_REF:
4213       case REALPART_EXPR:
4214       case IMAGPART_EXPR:
4215         x = TREE_OPERAND (x, 0);
4216         break;
4217
4218       case PARM_DECL:
4219         if (x == current_class_ptr)
4220           {
4221             error ("cannot take the address of `this', which is an rvalue expression");
4222             TREE_ADDRESSABLE (x) = 1; /* so compiler doesn't die later */
4223             return true;
4224           }
4225         /* FALLTHRU */
4226
4227       case VAR_DECL:
4228         /* Caller should not be trying to mark initialized
4229            constant fields addressable.  */
4230         my_friendly_assert (DECL_LANG_SPECIFIC (x) == 0
4231                             || DECL_IN_AGGR_P (x) == 0
4232                             || TREE_STATIC (x)
4233                             || DECL_EXTERNAL (x), 314);
4234         /* FALLTHRU */
4235
4236       case CONST_DECL:
4237       case RESULT_DECL:
4238         if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x)
4239             && !DECL_ARTIFICIAL (x) && extra_warnings)
4240           warning ("address requested for `%D', which is declared `register'",
4241                       x);
4242         TREE_ADDRESSABLE (x) = 1;
4243         put_var_into_stack (x, /*rescan=*/true);
4244         return true;
4245
4246       case FUNCTION_DECL:
4247         TREE_ADDRESSABLE (x) = 1;
4248         TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (x)) = 1;
4249         return true;
4250
4251       case CONSTRUCTOR:
4252         TREE_ADDRESSABLE (x) = 1;
4253         return true;
4254
4255       case TARGET_EXPR:
4256         TREE_ADDRESSABLE (x) = 1;
4257         cxx_mark_addressable (TREE_OPERAND (x, 0));
4258         return true;
4259
4260       default:
4261         return true;
4262     }
4263 }
4264 \f
4265 /* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
4266
4267 tree
4268 build_x_conditional_expr (tree ifexp, tree op1, tree op2)
4269 {
4270   tree orig_ifexp = ifexp;
4271   tree orig_op1 = op1;
4272   tree orig_op2 = op2;
4273   tree expr;
4274
4275   if (processing_template_decl)
4276     {
4277       /* The standard says that the expression is type-dependent if
4278          IFEXP is type-dependent, even though the eventual type of the
4279          expression doesn't dependent on IFEXP.  */
4280       if (type_dependent_expression_p (ifexp)
4281           || type_dependent_expression_p (op1)
4282           || type_dependent_expression_p (op2))
4283         return build_min_nt (COND_EXPR, ifexp, op1, op2);
4284       ifexp = build_non_dependent_expr (ifexp);
4285       op1 = build_non_dependent_expr (op1);
4286       op2 = build_non_dependent_expr (op2);
4287     }
4288
4289   expr = build_conditional_expr (ifexp, op1, op2);
4290   if (processing_template_decl && expr != error_mark_node)
4291     return build_min_non_dep (COND_EXPR, expr,
4292                               orig_ifexp, orig_op1, orig_op2);
4293   return expr;
4294 }
4295 \f
4296 /* Given a list of expressions, return a compound expression
4297    that performs them all and returns the value of the last of them. */
4298
4299 tree build_x_compound_expr_from_list (tree list, const char *msg)
4300 {
4301   tree expr = TREE_VALUE (list);
4302
4303   if (TREE_CHAIN (list))
4304     {
4305       if (msg)
4306         pedwarn ("%s expression list treated as compound expression", msg);
4307
4308       for (list = TREE_CHAIN (list); list; list = TREE_CHAIN (list))
4309         expr = build_x_compound_expr (expr, TREE_VALUE (list));
4310     }
4311
4312   return expr;
4313 }
4314
4315 /* Handle overloading of the ',' operator when needed.  */
4316
4317 tree
4318 build_x_compound_expr (tree op1, tree op2)
4319 {
4320   tree result;
4321   tree orig_op1 = op1;
4322   tree orig_op2 = op2;
4323
4324   if (processing_template_decl)
4325     {
4326       if (type_dependent_expression_p (op1)
4327           || type_dependent_expression_p (op2))
4328         return build_min_nt (COMPOUND_EXPR, op1, op2);
4329       op1 = build_non_dependent_expr (op1);
4330       op2 = build_non_dependent_expr (op2);
4331     }
4332
4333   result = build_new_op (COMPOUND_EXPR, LOOKUP_NORMAL, op1, op2, NULL_TREE);
4334   if (!result)
4335     result = build_compound_expr (op1, op2);
4336
4337   if (processing_template_decl && result != error_mark_node)
4338     return build_min_non_dep (COMPOUND_EXPR, result, orig_op1, orig_op2);
4339
4340   return result;
4341 }
4342
4343 /* Build a compound expression. */
4344
4345 tree
4346 build_compound_expr (tree lhs, tree rhs)
4347 {
4348   lhs = decl_constant_value (lhs);
4349   lhs = convert_to_void (lhs, "left-hand operand of comma");
4350
4351   if (lhs == error_mark_node || rhs == error_mark_node)
4352     return error_mark_node;
4353
4354   if (TREE_CODE (rhs) == TARGET_EXPR)
4355     {
4356       /* If the rhs is a TARGET_EXPR, then build the compound
4357          expression inside the target_expr's initializer. This
4358          helps the compiler to eliminate unncessary temporaries.  */
4359       tree init = TREE_OPERAND (rhs, 1);
4360
4361       init = build (COMPOUND_EXPR, TREE_TYPE (init), lhs, init);
4362       TREE_OPERAND (rhs, 1) = init;
4363
4364       return rhs;
4365     }
4366
4367   return build (COMPOUND_EXPR, TREE_TYPE (rhs), lhs, rhs);
4368 }
4369
4370 /* Issue an error message if casting from SRC_TYPE to DEST_TYPE casts
4371    away constness.  DESCRIPTION explains what operation is taking
4372    place.  */
4373
4374 static void
4375 check_for_casting_away_constness (tree src_type, tree dest_type,
4376                                   const char *description)
4377 {
4378   if (casts_away_constness (src_type, dest_type))
4379     error ("%s from type `%T' to type `%T' casts away constness",
4380            description, src_type, dest_type);
4381 }
4382
4383 /* Return an expression representing static_cast<TYPE>(EXPR).  */
4384
4385 tree
4386 build_static_cast (tree type, tree expr)
4387 {
4388   tree intype;
4389   tree result;
4390
4391   if (type == error_mark_node || expr == error_mark_node)
4392     return error_mark_node;
4393
4394   if (processing_template_decl)
4395     {
4396       expr = build_min (STATIC_CAST_EXPR, type, expr);
4397       /* We don't know if it will or will not have side effects.  */
4398       TREE_SIDE_EFFECTS (expr) = 1;
4399       return expr;
4400     }
4401
4402   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4403      Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4404   if (TREE_CODE (type) != REFERENCE_TYPE
4405       && TREE_CODE (expr) == NOP_EXPR
4406       && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4407     expr = TREE_OPERAND (expr, 0);
4408
4409   intype = TREE_TYPE (expr);
4410
4411   /* [expr.static.cast]
4412
4413      An lvalue of type "cv1 B", where B is a class type, can be cast
4414      to type "reference to cv2 D", where D is a class derived (clause
4415      _class.derived_) from B, if a valid standard conversion from
4416      "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the
4417      same cv-qualification as, or greater cv-qualification than, cv1,
4418      and B is not a virtual base class of D.  */
4419   /* We check this case before checking the validity of "TYPE t =
4420      EXPR;" below because for this case:
4421
4422        struct B {};
4423        struct D : public B { D(const B&); };
4424        extern B& b;
4425        void f() { static_cast<const D&>(b); }
4426
4427      we want to avoid constructing a new D.  The standard is not
4428      completely clear about this issue, but our interpretation is
4429      consistent with other compilers.  */
4430   if (TREE_CODE (type) == REFERENCE_TYPE
4431       && CLASS_TYPE_P (TREE_TYPE (type))
4432       && CLASS_TYPE_P (intype)
4433       && real_lvalue_p (expr)
4434       && DERIVED_FROM_P (intype, TREE_TYPE (type))
4435       && can_convert (build_pointer_type (TYPE_MAIN_VARIANT (intype)),
4436                       build_pointer_type (TYPE_MAIN_VARIANT
4437                                           (TREE_TYPE (type))))
4438       && at_least_as_qualified_p (TREE_TYPE (type), intype))
4439     {
4440       /* There is a standard conversion from "D*" to "B*" even if "B"
4441          is ambiguous or inaccessible.  Therefore, we ask lookup_base
4442          to check these conditions.  */
4443       tree base = lookup_base (TREE_TYPE (type), intype, ba_check, NULL);
4444
4445       /* Convert from "B*" to "D*".  This function will check that "B"
4446          is not a virtual base of "D".  */
4447       expr = build_base_path (MINUS_EXPR, build_address (expr),
4448                               base, /*nonnull=*/false);
4449       /* Convert the pointer to a reference -- but then remember that
4450          there are no expressions with reference type in C++.  */
4451       return convert_from_reference (build_nop (type, expr));
4452     }
4453
4454   /* [expr.static.cast]
4455
4456      An expression e can be explicitly converted to a type T using a
4457      static_cast of the form static_cast<T>(e) if the declaration T
4458      t(e);" is well-formed, for some invented temporary variable
4459      t.  */
4460   result = perform_direct_initialization_if_possible (type, expr);
4461   if (result)
4462     return convert_from_reference (result);
4463
4464   /* [expr.static.cast]
4465
4466      Any expression can be explicitly converted to type cv void.  */
4467   if (TREE_CODE (type) == VOID_TYPE)
4468     return convert_to_void (expr, /*implicit=*/NULL);
4469
4470   /* [expr.static.cast]
4471
4472      The inverse of any standard conversion sequence (clause _conv_),
4473      other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer
4474      (_conv.array_), function-to-pointer (_conv.func_), and boolean
4475      (_conv.bool_) conversions, can be performed explicitly using
4476      static_cast subject to the restriction that the explicit
4477      conversion does not cast away constness (_expr.const.cast_), and
4478      the following additional rules for specific cases:  */
4479   /* For reference, the conversions not excluded are: integral
4480      promotions, floating point promotion, integral conversions,
4481      floating point conversions, floating-integral conversions,
4482      pointer conversions, and pointer to member conversions.  */
4483   if ((ARITHMETIC_TYPE_P (type) && ARITHMETIC_TYPE_P (intype))
4484       /* DR 128
4485
4486          A value of integral _or enumeration_ type can be explicitly
4487          converted to an enumeration type.  */
4488       || (INTEGRAL_OR_ENUMERATION_TYPE_P (type)
4489           && INTEGRAL_OR_ENUMERATION_TYPE_P (intype)))
4490     /* Really, build_c_cast should defer to this function rather
4491        than the other way around.  */
4492     return build_c_cast (type, expr);
4493
4494   if (TYPE_PTR_P (type) && TYPE_PTR_P (intype)
4495       && CLASS_TYPE_P (TREE_TYPE (type))
4496       && CLASS_TYPE_P (TREE_TYPE (intype))
4497       && can_convert (build_pointer_type (TYPE_MAIN_VARIANT
4498                                           (TREE_TYPE (intype))),
4499                       build_pointer_type (TYPE_MAIN_VARIANT
4500                                           (TREE_TYPE (type)))))
4501     {
4502       tree base;
4503
4504       check_for_casting_away_constness (intype, type, "static_cast");
4505       base = lookup_base (TREE_TYPE (type), TREE_TYPE (intype), ba_check,
4506                           NULL);
4507       return build_base_path (MINUS_EXPR, expr, base, /*nonnull=*/false);
4508     }
4509
4510   if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
4511       || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
4512     {
4513       tree c1;
4514       tree c2;
4515       tree t1;
4516       tree t2;
4517
4518       c1 = TYPE_PTRMEM_CLASS_TYPE (intype);
4519       c2 = TYPE_PTRMEM_CLASS_TYPE (type);
4520
4521       if (TYPE_PTRMEM_P (type))
4522         {
4523           t1 = (build_ptrmem_type
4524                 (c1,
4525                  TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (intype))));
4526           t2 = (build_ptrmem_type
4527                 (c2,
4528                  TYPE_MAIN_VARIANT (TYPE_PTRMEM_POINTED_TO_TYPE (type))));
4529         }
4530       else
4531         {
4532           t1 = intype;
4533           t2 = type;
4534         }
4535       if (can_convert (t1, t2))
4536         {
4537           check_for_casting_away_constness (intype, type, "static_cast");
4538           if (TYPE_PTRMEM_P (type))
4539             {
4540               tree delta;
4541
4542               if (TREE_CODE (expr) == PTRMEM_CST)
4543                 expr = cplus_expand_constant (expr);
4544               delta = get_delta_difference (c1, c2, /*force=*/1);
4545               if (!integer_zerop (delta))
4546                 expr = cp_build_binary_op (PLUS_EXPR,
4547                                            build_nop (ptrdiff_type_node, expr),
4548                                            delta);
4549               return build_nop (type, expr);
4550             }
4551           else
4552             return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr,
4553                                      /*force=*/1);
4554         }
4555     }
4556
4557   /* [expr.static.cast]
4558
4559      An rvalue of type "pointer to cv void" can be explicitly
4560      converted to a pointer to object type.  A value of type pointer
4561      to object converted to "pointer to cv void" and back to the
4562      original pointer type will have its original value.  */
4563   if (TREE_CODE (intype) == POINTER_TYPE
4564       && VOID_TYPE_P (TREE_TYPE (intype))
4565       && TYPE_PTROB_P (type))
4566     {
4567       check_for_casting_away_constness (intype, type, "static_cast");
4568       return build_nop (type, expr);
4569     }
4570
4571   error ("invalid static_cast from type `%T' to type `%T'", intype, type);
4572   return error_mark_node;
4573 }
4574
4575 tree
4576 build_reinterpret_cast (tree type, tree expr)
4577 {
4578   tree intype;
4579
4580   if (type == error_mark_node || expr == error_mark_node)
4581     return error_mark_node;
4582
4583   if (processing_template_decl)
4584     {
4585       tree t = build_min (REINTERPRET_CAST_EXPR, type, expr);
4586
4587       if (!TREE_SIDE_EFFECTS (t)
4588           && type_dependent_expression_p (expr))
4589         /* There might turn out to be side effects inside expr.  */
4590         TREE_SIDE_EFFECTS (t) = 1;
4591       return t;
4592     }
4593
4594   if (TREE_CODE (type) != REFERENCE_TYPE)
4595     {
4596       expr = decay_conversion (expr);
4597
4598       /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4599          Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4600       if (TREE_CODE (expr) == NOP_EXPR
4601           && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4602         expr = TREE_OPERAND (expr, 0);
4603     }
4604
4605   intype = TREE_TYPE (expr);
4606
4607   if (TREE_CODE (type) == REFERENCE_TYPE)
4608     {
4609       if (! real_lvalue_p (expr))
4610         {
4611           error ("invalid reinterpret_cast of an rvalue expression of type `%T' to type `%T'", intype, type);
4612           return error_mark_node;
4613         }
4614       expr = build_unary_op (ADDR_EXPR, expr, 0);
4615       if (expr != error_mark_node)
4616         expr = build_reinterpret_cast
4617           (build_pointer_type (TREE_TYPE (type)), expr);
4618       if (expr != error_mark_node)
4619         expr = build_indirect_ref (expr, 0);
4620       return expr;
4621     }
4622   else if (same_type_ignoring_top_level_qualifiers_p (intype, type))
4623     return build_static_cast (type, expr);
4624
4625   if (TYPE_PTR_P (type) && (TREE_CODE (intype) == INTEGER_TYPE
4626                             || TREE_CODE (intype) == ENUMERAL_TYPE))
4627     /* OK */;
4628   else if (TREE_CODE (type) == INTEGER_TYPE && TYPE_PTR_P (intype))
4629     {
4630       if (TYPE_PRECISION (type) < TYPE_PRECISION (intype))
4631         pedwarn ("reinterpret_cast from `%T' to `%T' loses precision",
4632                     intype, type);
4633     }
4634   else if ((TYPE_PTRFN_P (type) && TYPE_PTRFN_P (intype))
4635            || (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
4636     {
4637       expr = decl_constant_value (expr);
4638       return fold (build1 (NOP_EXPR, type, expr));
4639     }
4640   else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
4641            || (TYPE_PTROBV_P (type) && TYPE_PTROBV_P (intype)))
4642     {
4643       check_for_casting_away_constness (intype, type, "reinterpret_cast");
4644       expr = decl_constant_value (expr);
4645       return fold (build1 (NOP_EXPR, type, expr));
4646     }
4647   else if ((TYPE_PTRFN_P (type) && TYPE_PTROBV_P (intype))
4648            || (TYPE_PTRFN_P (intype) && TYPE_PTROBV_P (type)))
4649     {
4650       pedwarn ("ISO C++ forbids casting between pointer-to-function and pointer-to-object");
4651       expr = decl_constant_value (expr);
4652       return fold (build1 (NOP_EXPR, type, expr));
4653     }
4654   else
4655     {
4656       error ("invalid reinterpret_cast from type `%T' to type `%T'",
4657                 intype, type);
4658       return error_mark_node;
4659     }
4660
4661   return cp_convert (type, expr);
4662 }
4663
4664 tree
4665 build_const_cast (tree type, tree expr)
4666 {
4667   tree intype;
4668
4669   if (type == error_mark_node || expr == error_mark_node)
4670     return error_mark_node;
4671
4672   if (processing_template_decl)
4673     {
4674       tree t = build_min (CONST_CAST_EXPR, type, expr);
4675
4676       if (!TREE_SIDE_EFFECTS (t)
4677           && type_dependent_expression_p (expr))
4678         /* There might turn out to be side effects inside expr.  */
4679         TREE_SIDE_EFFECTS (t) = 1;
4680       return t;
4681     }
4682
4683   if (!POINTER_TYPE_P (type))
4684     error ("invalid use of const_cast with type `%T', which is not a pointer, reference, nor a pointer-to-data-member type", type);
4685   else if (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
4686     {
4687       error ("invalid use of const_cast with type `%T', which is a pointer or reference to a function type", type);
4688       return error_mark_node;
4689     }
4690
4691   if (TREE_CODE (type) != REFERENCE_TYPE)
4692     {
4693       expr = decay_conversion (expr);
4694
4695       /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4696          Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4697       if (TREE_CODE (expr) == NOP_EXPR
4698           && TREE_TYPE (expr) == TREE_TYPE (TREE_OPERAND (expr, 0)))
4699         expr = TREE_OPERAND (expr, 0);
4700     }
4701
4702   intype = TREE_TYPE (expr);
4703
4704   if (same_type_ignoring_top_level_qualifiers_p (intype, type))
4705     return build_static_cast (type, expr);
4706   else if (TREE_CODE (type) == REFERENCE_TYPE)
4707     {
4708       if (! real_lvalue_p (expr))
4709         {
4710           error ("invalid const_cast of an rvalue of type `%T' to type `%T'", intype, type);
4711           return error_mark_node;
4712         }
4713
4714       if (comp_ptr_ttypes_const (TREE_TYPE (type), intype))
4715         {
4716           expr = build_unary_op (ADDR_EXPR, expr, 0);
4717           expr = build1 (NOP_EXPR, type, expr);
4718           return convert_from_reference (expr);
4719         }
4720     }
4721   else if (((TREE_CODE (type) == POINTER_TYPE
4722              && TREE_CODE (intype) == POINTER_TYPE)
4723             || (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype)))
4724            && comp_ptr_ttypes_const (TREE_TYPE (type), TREE_TYPE (intype)))
4725     return cp_convert (type, expr);
4726
4727   error ("invalid const_cast from type `%T' to type `%T'", intype, type);
4728   return error_mark_node;
4729 }
4730
4731 /* Build an expression representing a cast to type TYPE of expression EXPR.
4732
4733    ALLOW_NONCONVERTING is true if we should allow non-converting constructors
4734    when doing the cast.  */
4735
4736 tree
4737 build_c_cast (tree type, tree expr)
4738 {
4739   register tree value = expr;
4740   tree otype;
4741
4742   if (type == error_mark_node || expr == error_mark_node)
4743     return error_mark_node;
4744
4745   if (processing_template_decl)
4746     {
4747       tree t = build_min (CAST_EXPR, type,
4748                           tree_cons (NULL_TREE, value, NULL_TREE));
4749       /* We don't know if it will or will not have side effects. */
4750       TREE_SIDE_EFFECTS (t) = 1;
4751       return t;
4752     }
4753
4754   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4755      Strip such NOP_EXPRs if VALUE is being used in non-lvalue context.  */
4756   if (TREE_CODE (type) != REFERENCE_TYPE
4757       && TREE_CODE (value) == NOP_EXPR
4758       && TREE_TYPE (value) == TREE_TYPE (TREE_OPERAND (value, 0)))
4759     value = TREE_OPERAND (value, 0);
4760
4761   if (TREE_CODE (type) == ARRAY_TYPE)
4762     {
4763       /* Allow casting from T1* to T2[] because Cfront allows it.
4764          NIHCL uses it. It is not valid ISO C++ however.  */
4765       if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
4766         {
4767           pedwarn ("ISO C++ forbids casting to an array type `%T'", type);
4768           type = build_pointer_type (TREE_TYPE (type));
4769         }
4770       else
4771         {
4772           error ("ISO C++ forbids casting to an array type `%T'", type);
4773           return error_mark_node;
4774         }
4775     }
4776
4777   if (TREE_CODE (type) == FUNCTION_TYPE
4778       || TREE_CODE (type) == METHOD_TYPE)
4779     {
4780       error ("invalid cast to function type `%T'", type);
4781       return error_mark_node;
4782     }
4783
4784   if (TREE_CODE (type) == VOID_TYPE)
4785     {
4786       /* Conversion to void does not cause any of the normal function to
4787        * pointer, array to pointer and lvalue to rvalue decays.  */
4788
4789       value = convert_to_void (value, /*implicit=*/NULL);
4790       return value;
4791     }
4792
4793   if (!complete_type_or_else (type, NULL_TREE))
4794     return error_mark_node;
4795
4796   /* Convert functions and arrays to pointers and
4797      convert references to their expanded types,
4798      but don't convert any other types.  If, however, we are
4799      casting to a class type, there's no reason to do this: the
4800      cast will only succeed if there is a converting constructor,
4801      and the default conversions will be done at that point.  In
4802      fact, doing the default conversion here is actually harmful
4803      in cases like this:
4804
4805      typedef int A[2];
4806      struct S { S(const A&); };
4807
4808      since we don't want the array-to-pointer conversion done.  */
4809   if (!IS_AGGR_TYPE (type))
4810     {
4811       if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
4812           || (TREE_CODE (TREE_TYPE (value)) == METHOD_TYPE
4813               /* Don't do the default conversion on a ->* expression.  */
4814               && ! (TREE_CODE (type) == POINTER_TYPE
4815                     && bound_pmf_p (value)))
4816           || TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
4817           || TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE)
4818         value = decay_conversion (value);
4819     }
4820   else if (TREE_CODE (TREE_TYPE (value)) == REFERENCE_TYPE)
4821     /* However, even for class types, we still need to strip away
4822        the reference type, since the call to convert_force below
4823        does not expect the input expression to be of reference
4824        type.  */
4825     value = convert_from_reference (value);
4826
4827   otype = TREE_TYPE (value);
4828
4829   /* Optionally warn about potentially worrisome casts.  */
4830
4831   if (warn_cast_qual
4832       && TREE_CODE (type) == POINTER_TYPE
4833       && TREE_CODE (otype) == POINTER_TYPE
4834       && !at_least_as_qualified_p (TREE_TYPE (type),
4835                                    TREE_TYPE (otype)))
4836     warning ("cast from `%T' to `%T' discards qualifiers from pointer target type",
4837                 otype, type);
4838
4839   if (TREE_CODE (type) == INTEGER_TYPE
4840       && TYPE_PTR_P (otype)
4841       && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
4842     warning ("cast from pointer to integer of different size");
4843
4844   if (TYPE_PTR_P (type)
4845       && TREE_CODE (otype) == INTEGER_TYPE
4846       && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
4847       /* Don't warn about converting any constant.  */
4848       && !TREE_CONSTANT (value))
4849     warning ("cast to pointer from integer of different size");
4850
4851   if (TREE_CODE (type) == REFERENCE_TYPE)
4852     value = (convert_from_reference
4853              (convert_to_reference (type, value, CONV_C_CAST,
4854                                     LOOKUP_COMPLAIN, NULL_TREE)));
4855   else
4856     {
4857       tree ovalue;
4858
4859       value = decl_constant_value (value);
4860
4861       ovalue = value;
4862       value = convert_force (type, value, CONV_C_CAST);
4863
4864       /* Ignore any integer overflow caused by the cast.  */
4865       if (TREE_CODE (value) == INTEGER_CST)
4866         {
4867           TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
4868           TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
4869         }
4870     }
4871
4872   /* Warn about possible alignment problems.  Do this here when we will have
4873      instantiated any necessary template types.  */
4874   if (STRICT_ALIGNMENT && warn_cast_align
4875       && TREE_CODE (type) == POINTER_TYPE
4876       && TREE_CODE (otype) == POINTER_TYPE
4877       && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
4878       && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
4879       && COMPLETE_TYPE_P (TREE_TYPE (otype))
4880       && COMPLETE_TYPE_P (TREE_TYPE (type))
4881       && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
4882     warning ("cast from `%T' to `%T' increases required alignment of target type",
4883                 otype, type);
4884
4885     /* Always produce some operator for an explicit cast,
4886        so we can tell (for -pedantic) that the cast is no lvalue.  */
4887   if (TREE_CODE (type) != REFERENCE_TYPE && value == expr
4888       && real_lvalue_p (value))
4889     value = non_lvalue (value);
4890
4891   return value;
4892 }
4893 \f
4894 /* Build an assignment expression of lvalue LHS from value RHS.
4895    MODIFYCODE is the code for a binary operator that we use
4896    to combine the old value of LHS with RHS to get the new value.
4897    Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
4898
4899    C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed.  */
4900
4901 tree
4902 build_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
4903 {
4904   register tree result;
4905   tree newrhs = rhs;
4906   tree lhstype = TREE_TYPE (lhs);
4907   tree olhstype = lhstype;
4908   tree olhs = lhs;
4909
4910   /* Avoid duplicate error messages from operands that had errors.  */
4911   if (lhs == error_mark_node || rhs == error_mark_node)
4912     return error_mark_node;
4913
4914   /* Handle control structure constructs used as "lvalues".  */
4915   switch (TREE_CODE (lhs))
4916     {
4917       /* Handle --foo = 5; as these are valid constructs in C++ */
4918     case PREDECREMENT_EXPR:
4919     case PREINCREMENT_EXPR:
4920       if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
4921         lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs),
4922                      stabilize_reference (TREE_OPERAND (lhs, 0)),
4923                      TREE_OPERAND (lhs, 1));
4924       return build (COMPOUND_EXPR, lhstype,
4925                     lhs,
4926                     build_modify_expr (TREE_OPERAND (lhs, 0),
4927                                        modifycode, rhs));
4928
4929       /* Handle (a, b) used as an "lvalue".  */
4930     case COMPOUND_EXPR:
4931       newrhs = build_modify_expr (TREE_OPERAND (lhs, 1),
4932                                   modifycode, rhs);
4933       if (newrhs == error_mark_node)
4934         return error_mark_node;
4935       return build (COMPOUND_EXPR, lhstype,
4936                     TREE_OPERAND (lhs, 0), newrhs);
4937
4938     case MODIFY_EXPR:
4939       if (TREE_SIDE_EFFECTS (TREE_OPERAND (lhs, 0)))
4940         lhs = build (TREE_CODE (lhs), TREE_TYPE (lhs),
4941                      stabilize_reference (TREE_OPERAND (lhs, 0)),
4942                      TREE_OPERAND (lhs, 1));
4943       newrhs = build_modify_expr (TREE_OPERAND (lhs, 0), modifycode, rhs);
4944       if (newrhs == error_mark_node)
4945         return error_mark_node;
4946       return build (COMPOUND_EXPR, lhstype, lhs, newrhs);
4947
4948       /* Handle (a ? b : c) used as an "lvalue".  */
4949     case COND_EXPR:
4950       {
4951         /* Produce (a ? (b = rhs) : (c = rhs))
4952            except that the RHS goes through a save-expr
4953            so the code to compute it is only emitted once.  */
4954         tree cond;
4955         tree preeval = NULL_TREE;
4956
4957         rhs = stabilize_expr (rhs, &preeval);
4958
4959         /* Check this here to avoid odd errors when trying to convert
4960            a throw to the type of the COND_EXPR.  */
4961         if (!lvalue_or_else (lhs, "assignment"))
4962           return error_mark_node;
4963
4964         cond = build_conditional_expr
4965           (TREE_OPERAND (lhs, 0),
4966            build_modify_expr (cp_convert (TREE_TYPE (lhs),
4967                                           TREE_OPERAND (lhs, 1)),
4968                               modifycode, rhs),
4969            build_modify_expr (cp_convert (TREE_TYPE (lhs),
4970                                           TREE_OPERAND (lhs, 2)),
4971                               modifycode, rhs));
4972
4973         if (cond == error_mark_node)
4974           return cond;
4975         /* Make sure the code to compute the rhs comes out
4976            before the split.  */
4977         return build (COMPOUND_EXPR, TREE_TYPE (lhs), preeval, cond);
4978       }
4979
4980     default:
4981       break;
4982     }
4983
4984   if (modifycode == INIT_EXPR)
4985     {
4986       if (TREE_CODE (rhs) == CONSTRUCTOR)
4987         {
4988           my_friendly_assert (same_type_p (TREE_TYPE (rhs), lhstype),
4989                               20011220);
4990           result = build (INIT_EXPR, lhstype, lhs, rhs);
4991           TREE_SIDE_EFFECTS (result) = 1;
4992           return result;
4993         }
4994       else if (! IS_AGGR_TYPE (lhstype))
4995         /* Do the default thing */;
4996       else
4997         {
4998           result = build_special_member_call (lhs, complete_ctor_identifier,
4999                                               build_tree_list (NULL_TREE, rhs),
5000                                               TYPE_BINFO (lhstype),
5001                                               LOOKUP_NORMAL);
5002           if (result == NULL_TREE)
5003             return error_mark_node;
5004           return result;
5005         }
5006     }
5007   else
5008     {
5009       if (TREE_CODE (lhstype) == REFERENCE_TYPE)
5010         {
5011           lhs = convert_from_reference (lhs);
5012           olhstype = lhstype = TREE_TYPE (lhs);
5013         }
5014       lhs = require_complete_type (lhs);
5015       if (lhs == error_mark_node)
5016         return error_mark_node;
5017
5018       if (modifycode == NOP_EXPR)
5019         {
5020           /* `operator=' is not an inheritable operator.  */
5021           if (! IS_AGGR_TYPE (lhstype))
5022             /* Do the default thing */;
5023           else
5024             {
5025               result = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL,
5026                                      lhs, rhs, make_node (NOP_EXPR));
5027               if (result == NULL_TREE)
5028                 return error_mark_node;
5029               return result;
5030             }
5031           lhstype = olhstype;
5032         }
5033       else
5034         {
5035           /* A binary op has been requested.  Combine the old LHS
5036              value with the RHS producing the value we should actually
5037              store into the LHS.  */
5038
5039           my_friendly_assert (!PROMOTES_TO_AGGR_TYPE (lhstype, REFERENCE_TYPE),
5040                               978652);
5041           lhs = stabilize_reference (lhs);
5042           newrhs = cp_build_binary_op (modifycode, lhs, rhs);
5043           if (newrhs == error_mark_node)
5044             {
5045               error ("  in evaluation of `%Q(%#T, %#T)'", modifycode,
5046                      TREE_TYPE (lhs), TREE_TYPE (rhs));
5047               return error_mark_node;
5048             }
5049
5050           /* Now it looks like a plain assignment.  */
5051           modifycode = NOP_EXPR;
5052         }
5053       my_friendly_assert (TREE_CODE (lhstype) != REFERENCE_TYPE, 20011220);
5054       my_friendly_assert (TREE_CODE (TREE_TYPE (newrhs)) != REFERENCE_TYPE,
5055                           20011220);
5056     }
5057
5058   /* Handle a cast used as an "lvalue".
5059      We have already performed any binary operator using the value as cast.
5060      Now convert the result to the cast type of the lhs,
5061      and then true type of the lhs and store it there;
5062      then convert result back to the cast type to be the value
5063      of the assignment.  */
5064
5065   switch (TREE_CODE (lhs))
5066     {
5067     case NOP_EXPR:
5068     case CONVERT_EXPR:
5069     case FLOAT_EXPR:
5070     case FIX_TRUNC_EXPR:
5071     case FIX_FLOOR_EXPR:
5072     case FIX_ROUND_EXPR:
5073     case FIX_CEIL_EXPR:
5074       {
5075         tree inner_lhs = TREE_OPERAND (lhs, 0);
5076         tree result;
5077
5078         if (TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE
5079             || TREE_CODE (TREE_TYPE (newrhs)) == FUNCTION_TYPE
5080             || TREE_CODE (TREE_TYPE (newrhs)) == METHOD_TYPE
5081             || TREE_CODE (TREE_TYPE (newrhs)) == OFFSET_TYPE)
5082           newrhs = decay_conversion (newrhs);
5083
5084         /* ISO C++ 5.4/1: The result is an lvalue if T is a reference
5085            type, otherwise the result is an rvalue.  */
5086         if (! lvalue_p (lhs))
5087           pedwarn ("ISO C++ forbids cast to non-reference type used as lvalue");
5088
5089         result = build_modify_expr (inner_lhs, NOP_EXPR,
5090                                     cp_convert (TREE_TYPE (inner_lhs),
5091                                                 cp_convert (lhstype, newrhs)));
5092         if (result == error_mark_node)
5093           return result;
5094         return cp_convert (TREE_TYPE (lhs), result);
5095       }
5096
5097     default:
5098       break;
5099     }
5100
5101   /* Now we have handled acceptable kinds of LHS that are not truly lvalues.
5102      Reject anything strange now.  */
5103
5104   if (!lvalue_or_else (lhs, "assignment"))
5105     return error_mark_node;
5106
5107   /* Warn about modifying something that is `const'.  Don't warn if
5108      this is initialization.  */
5109   if (modifycode != INIT_EXPR
5110       && (TREE_READONLY (lhs) || CP_TYPE_CONST_P (lhstype)
5111           /* Functions are not modifiable, even though they are
5112              lvalues.  */
5113           || TREE_CODE (TREE_TYPE (lhs)) == FUNCTION_TYPE
5114           || TREE_CODE (TREE_TYPE (lhs)) == METHOD_TYPE
5115           /* If it's an aggregate and any field is const, then it is
5116              effectively const.  */
5117           || (CLASS_TYPE_P (lhstype)
5118               && C_TYPE_FIELDS_READONLY (lhstype))))
5119     readonly_error (lhs, "assignment", 0);
5120
5121   /* If storing into a structure or union member, it has probably been
5122      given type `int'.  Compute the type that would go with the actual
5123      amount of storage the member occupies.  */
5124
5125   if (TREE_CODE (lhs) == COMPONENT_REF
5126       && (TREE_CODE (lhstype) == INTEGER_TYPE
5127           || TREE_CODE (lhstype) == REAL_TYPE
5128           || TREE_CODE (lhstype) == ENUMERAL_TYPE))
5129     {
5130       lhstype = TREE_TYPE (get_unwidened (lhs, 0));
5131
5132       /* If storing in a field that is in actuality a short or narrower
5133          than one, we must store in the field in its actual type.  */
5134
5135       if (lhstype != TREE_TYPE (lhs))
5136         {
5137           lhs = copy_node (lhs);
5138           TREE_TYPE (lhs) = lhstype;
5139         }
5140     }
5141
5142   /* Convert new value to destination type.  */
5143
5144   if (TREE_CODE (lhstype) == ARRAY_TYPE)
5145     {
5146       int from_array;
5147
5148       if (!same_or_base_type_p (TYPE_MAIN_VARIANT (lhstype),
5149                                 TYPE_MAIN_VARIANT (TREE_TYPE (rhs))))
5150         {
5151           error ("incompatible types in assignment of `%T' to `%T'",
5152                  TREE_TYPE (rhs), lhstype);
5153           return error_mark_node;
5154         }
5155
5156       /* Allow array assignment in compiler-generated code.  */
5157       if (! DECL_ARTIFICIAL (current_function_decl))
5158         pedwarn ("ISO C++ forbids assignment of arrays");
5159
5160       from_array = TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE
5161                    ? 1 + (modifycode != INIT_EXPR): 0;
5162       return build_vec_init (lhs, NULL_TREE, newrhs, from_array);
5163     }
5164
5165   if (modifycode == INIT_EXPR)
5166     newrhs = convert_for_initialization (lhs, lhstype, newrhs, LOOKUP_NORMAL,
5167                                          "initialization", NULL_TREE, 0);
5168   else
5169     {
5170       /* Avoid warnings on enum bit fields.  */
5171       if (TREE_CODE (olhstype) == ENUMERAL_TYPE
5172           && TREE_CODE (lhstype) == INTEGER_TYPE)
5173         {
5174           newrhs = convert_for_assignment (olhstype, newrhs, "assignment",
5175                                            NULL_TREE, 0);
5176           newrhs = convert_force (lhstype, newrhs, 0);
5177         }
5178       else
5179         newrhs = convert_for_assignment (lhstype, newrhs, "assignment",
5180                                          NULL_TREE, 0);
5181       if (TREE_CODE (newrhs) == CALL_EXPR
5182           && TYPE_NEEDS_CONSTRUCTING (lhstype))
5183         newrhs = build_cplus_new (lhstype, newrhs);
5184
5185       /* Can't initialize directly from a TARGET_EXPR, since that would
5186          cause the lhs to be constructed twice, and possibly result in
5187          accidental self-initialization.  So we force the TARGET_EXPR to be
5188          expanded without a target.  */
5189       if (TREE_CODE (newrhs) == TARGET_EXPR)
5190         newrhs = build (COMPOUND_EXPR, TREE_TYPE (newrhs), newrhs,
5191                         TREE_OPERAND (newrhs, 0));
5192     }
5193
5194   if (newrhs == error_mark_node)
5195     return error_mark_node;
5196
5197   result = build (modifycode == NOP_EXPR ? MODIFY_EXPR : INIT_EXPR,
5198                   lhstype, lhs, newrhs);
5199
5200   TREE_SIDE_EFFECTS (result) = 1;
5201
5202   /* If we got the LHS in a different type for storing in,
5203      convert the result back to the nominal type of LHS
5204      so that the value we return always has the same type
5205      as the LHS argument.  */
5206
5207   if (olhstype == TREE_TYPE (result))
5208     return result;
5209   /* Avoid warnings converting integral types back into enums
5210      for enum bit fields.  */
5211   if (TREE_CODE (TREE_TYPE (result)) == INTEGER_TYPE
5212       && TREE_CODE (olhstype) == ENUMERAL_TYPE)
5213     {
5214       result = build (COMPOUND_EXPR, olhstype, result, olhs);
5215       TREE_NO_UNUSED_WARNING (result) = 1;
5216       return result;
5217     }
5218   return convert_for_assignment (olhstype, result, "assignment",
5219                                  NULL_TREE, 0);
5220 }
5221
5222 tree
5223 build_x_modify_expr (tree lhs, enum tree_code modifycode, tree rhs)
5224 {
5225   if (processing_template_decl)
5226     return build_min_nt (MODOP_EXPR, lhs,
5227                          build_min_nt (modifycode, NULL_TREE, NULL_TREE), rhs);
5228
5229   if (modifycode != NOP_EXPR)
5230     {
5231       tree rval = build_new_op (MODIFY_EXPR, LOOKUP_NORMAL, lhs, rhs,
5232                                 make_node (modifycode));
5233       if (rval)
5234         return rval;
5235     }
5236   return build_modify_expr (lhs, modifycode, rhs);
5237 }
5238
5239 \f
5240 /* Get difference in deltas for different pointer to member function
5241    types.  Returns an integer constant of type PTRDIFF_TYPE_NODE.  If
5242    the conversion is invalid, the constant is zero.  If FORCE is true,
5243    then allow reverse conversions as well.
5244
5245    Note that the naming of FROM and TO is kind of backwards; the return
5246    value is what we add to a TO in order to get a FROM.  They are named
5247    this way because we call this function to find out how to convert from
5248    a pointer to member of FROM to a pointer to member of TO.  */
5249
5250 static tree
5251 get_delta_difference (tree from, tree to, int force)
5252 {
5253   tree binfo;
5254   tree virt_binfo;
5255   base_kind kind;
5256
5257   binfo = lookup_base (to, from, ba_check, &kind);
5258   if (kind == bk_inaccessible || kind == bk_ambig)
5259     {
5260       error ("   in pointer to member function conversion");
5261       goto error;
5262     }
5263   if (!binfo)
5264     {
5265       if (!force)
5266         {
5267           error_not_base_type (from, to);
5268           error ("   in pointer to member conversion");
5269           goto error;
5270         }
5271       binfo = lookup_base (from, to, ba_check, &kind);
5272       if (!binfo)
5273         goto error;
5274       virt_binfo = binfo_from_vbase (binfo);
5275       if (virt_binfo)
5276         {
5277           /* This is a reinterpret cast, we choose to do nothing.  */
5278           warning ("pointer to member cast via virtual base `%T'",
5279                    BINFO_TYPE (virt_binfo));
5280           goto error;
5281         }
5282       return convert_to_integer (ptrdiff_type_node,
5283                                  size_diffop (size_zero_node,
5284                                               BINFO_OFFSET (binfo)));
5285     }
5286
5287   virt_binfo = binfo_from_vbase (binfo);
5288   if (!virt_binfo)
5289     return convert_to_integer (ptrdiff_type_node, BINFO_OFFSET (binfo));
5290
5291   /* This is a reinterpret cast, we choose to do nothing.  */
5292   if (force)
5293     warning ("pointer to member cast via virtual base `%T'",
5294              BINFO_TYPE (virt_binfo));
5295   else
5296     error ("pointer to member conversion via virtual base `%T'",
5297            BINFO_TYPE (virt_binfo));
5298
5299  error:
5300   return convert_to_integer(ptrdiff_type_node, integer_zero_node);
5301 }
5302
5303 /* Return a constructor for the pointer-to-member-function TYPE using
5304    the other components as specified.  */
5305
5306 tree
5307 build_ptrmemfunc1 (tree type, tree delta, tree pfn)
5308 {
5309   tree u = NULL_TREE;
5310   tree delta_field;
5311   tree pfn_field;
5312
5313   /* Pull the FIELD_DECLs out of the type.  */
5314   pfn_field = TYPE_FIELDS (type);
5315   delta_field = TREE_CHAIN (pfn_field);
5316
5317   /* Make sure DELTA has the type we want.  */
5318   delta = convert_and_check (delta_type_node, delta);
5319
5320   /* Finish creating the initializer.  */
5321   u = tree_cons (pfn_field, pfn,
5322                  build_tree_list (delta_field, delta));
5323   u = build_constructor (type, u);
5324   TREE_CONSTANT (u) = TREE_CONSTANT (pfn) && TREE_CONSTANT (delta);
5325   TREE_STATIC (u) = (TREE_CONSTANT (u)
5326                      && (initializer_constant_valid_p (pfn, TREE_TYPE (pfn))
5327                          != NULL_TREE)
5328                      && (initializer_constant_valid_p (delta, TREE_TYPE (delta))
5329                          != NULL_TREE));
5330   return u;
5331 }
5332
5333 /* Build a constructor for a pointer to member function.  It can be
5334    used to initialize global variables, local variable, or used
5335    as a value in expressions.  TYPE is the POINTER to METHOD_TYPE we
5336    want to be.
5337
5338    If FORCE is nonzero, then force this conversion, even if
5339    we would rather not do it.  Usually set when using an explicit
5340    cast.
5341
5342    Return error_mark_node, if something goes wrong.  */
5343
5344 tree
5345 build_ptrmemfunc (tree type, tree pfn, int force)
5346 {
5347   tree fn;
5348   tree pfn_type;
5349   tree to_type;
5350
5351   if (error_operand_p (pfn))
5352     return error_mark_node;
5353
5354   pfn_type = TREE_TYPE (pfn);
5355   to_type = build_ptrmemfunc_type (type);
5356
5357   /* Handle multiple conversions of pointer to member functions.  */
5358   if (TYPE_PTRMEMFUNC_P (pfn_type))
5359     {
5360       tree delta = NULL_TREE;
5361       tree npfn = NULL_TREE;
5362       tree n;
5363
5364       if (!force
5365           && !can_convert_arg (to_type, TREE_TYPE (pfn), pfn))
5366         error ("invalid conversion to type `%T' from type `%T'",
5367                   to_type, pfn_type);
5368
5369       n = get_delta_difference (TYPE_PTRMEMFUNC_OBJECT_TYPE (pfn_type),
5370                                 TYPE_PTRMEMFUNC_OBJECT_TYPE (to_type),
5371                                 force);
5372
5373       /* We don't have to do any conversion to convert a
5374          pointer-to-member to its own type.  But, we don't want to
5375          just return a PTRMEM_CST if there's an explicit cast; that
5376          cast should make the expression an invalid template argument.  */
5377       if (TREE_CODE (pfn) != PTRMEM_CST)
5378         {
5379           if (same_type_p (to_type, pfn_type))
5380             return pfn;
5381           else if (integer_zerop (n))
5382             return build_reinterpret_cast (to_type, pfn);
5383         }
5384
5385       if (TREE_SIDE_EFFECTS (pfn))
5386         pfn = save_expr (pfn);
5387
5388       /* Obtain the function pointer and the current DELTA.  */
5389       if (TREE_CODE (pfn) == PTRMEM_CST)
5390         expand_ptrmemfunc_cst (pfn, &delta, &npfn);
5391       else
5392         {
5393           npfn = build_ptrmemfunc_access_expr (pfn, pfn_identifier);
5394           delta = build_ptrmemfunc_access_expr (pfn, delta_identifier);
5395         }
5396
5397       /* Just adjust the DELTA field.  */
5398       my_friendly_assert (TREE_TYPE (delta) == ptrdiff_type_node, 20030727);
5399       if (TARGET_PTRMEMFUNC_VBIT_LOCATION == ptrmemfunc_vbit_in_delta)
5400         n = cp_build_binary_op (LSHIFT_EXPR, n, integer_one_node);
5401       delta = cp_build_binary_op (PLUS_EXPR, delta, n);
5402       return build_ptrmemfunc1 (to_type, delta, npfn);
5403     }
5404
5405   /* Handle null pointer to member function conversions.  */
5406   if (integer_zerop (pfn))
5407     {
5408       pfn = build_c_cast (type, integer_zero_node);
5409       return build_ptrmemfunc1 (to_type,
5410                                 integer_zero_node,
5411                                 pfn);
5412     }
5413
5414   if (type_unknown_p (pfn))
5415     return instantiate_type (type, pfn, tf_error | tf_warning);
5416
5417   fn = TREE_OPERAND (pfn, 0);
5418   my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0);
5419   return make_ptrmem_cst (to_type, fn);
5420 }
5421
5422 /* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST
5423    given by CST.
5424
5425    ??? There is no consistency as to the types returned for the above
5426    values.  Some code acts as if its a sizetype and some as if its
5427    integer_type_node.  */
5428
5429 void
5430 expand_ptrmemfunc_cst (tree cst, tree *delta, tree *pfn)
5431 {
5432   tree type = TREE_TYPE (cst);
5433   tree fn = PTRMEM_CST_MEMBER (cst);
5434   tree ptr_class, fn_class;
5435
5436   my_friendly_assert (TREE_CODE (fn) == FUNCTION_DECL, 0);
5437
5438   /* The class that the function belongs to.  */
5439   fn_class = DECL_CONTEXT (fn);
5440
5441   /* The class that we're creating a pointer to member of.  */
5442   ptr_class = TYPE_PTRMEMFUNC_OBJECT_TYPE (type);
5443
5444   /* First, calculate the adjustment to the function's class.  */
5445   *delta = get_delta_difference (fn_class, ptr_class, /*force=*/0);
5446
5447   if (!DECL_VIRTUAL_P (fn))
5448     *pfn = convert (TYPE_PTRMEMFUNC_FN_TYPE (type), build_addr_func (fn));
5449   else
5450     {
5451       /* If we're dealing with a virtual function, we have to adjust 'this'
5452          again, to point to the base which provides the vtable entry for
5453          fn; the call will do the opposite adjustment.  */
5454       tree orig_class = DECL_CONTEXT (fn);
5455       tree binfo = binfo_or_else (orig_class, fn_class);
5456       *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta),
5457                             *delta, BINFO_OFFSET (binfo)));
5458
5459       /* We set PFN to the vtable offset at which the function can be
5460          found, plus one (unless ptrmemfunc_vbit_in_delta, in which
5461          case delta is shifted left, and then incremented).  */
5462       *pfn = DECL_VINDEX (fn);
5463       *pfn = fold (build (MULT_EXPR, integer_type_node, *pfn,
5464                           TYPE_SIZE_UNIT (vtable_entry_type)));
5465
5466       switch (TARGET_PTRMEMFUNC_VBIT_LOCATION)
5467         {
5468         case ptrmemfunc_vbit_in_pfn:
5469           *pfn = fold (build (PLUS_EXPR, integer_type_node, *pfn,
5470                               integer_one_node));
5471           break;
5472
5473         case ptrmemfunc_vbit_in_delta:
5474           *delta = fold (build (LSHIFT_EXPR, TREE_TYPE (*delta),
5475                                 *delta, integer_one_node));
5476           *delta = fold (build (PLUS_EXPR, TREE_TYPE (*delta),
5477                                 *delta, integer_one_node));
5478           break;
5479
5480         default:
5481           abort ();
5482         }
5483
5484       *pfn = fold (build1 (NOP_EXPR, TYPE_PTRMEMFUNC_FN_TYPE (type),
5485                            *pfn));
5486     }
5487 }
5488
5489 /* Return an expression for PFN from the pointer-to-member function
5490    given by T.  */
5491
5492 tree
5493 pfn_from_ptrmemfunc (tree t)
5494 {
5495   if (TREE_CODE (t) == PTRMEM_CST)
5496     {
5497       tree delta;
5498       tree pfn;
5499
5500       expand_ptrmemfunc_cst (t, &delta, &pfn);
5501       if (pfn)
5502         return pfn;
5503     }
5504
5505   return build_ptrmemfunc_access_expr (t, pfn_identifier);
5506 }
5507
5508 /* Expression EXPR is about to be implicitly converted to TYPE.  Warn
5509    if this is a potentially dangerous thing to do.  Returns a possibly
5510    marked EXPR.  */
5511
5512 tree
5513 dubious_conversion_warnings (tree type, tree expr,
5514                              const char *errtype, tree fndecl, int parmnum)
5515 {
5516   type = non_reference (type);
5517
5518   /* Issue warnings about peculiar, but valid, uses of NULL.  */
5519   if (ARITHMETIC_TYPE_P (type) && expr == null_node)
5520     {
5521       if (fndecl)
5522         warning ("passing NULL used for non-pointer %s %P of `%D'",
5523                     errtype, parmnum, fndecl);
5524       else
5525         warning ("%s to non-pointer type `%T' from NULL", errtype, type);
5526     }
5527
5528   /* Warn about assigning a floating-point type to an integer type.  */
5529   if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
5530       && TREE_CODE (type) == INTEGER_TYPE)
5531     {
5532       if (fndecl)
5533         warning ("passing `%T' for %s %P of `%D'",
5534                     TREE_TYPE (expr), errtype, parmnum, fndecl);
5535       else
5536         warning ("%s to `%T' from `%T'", errtype, type, TREE_TYPE (expr));
5537     }
5538   /* And warn about assigning a negative value to an unsigned
5539      variable.  */
5540   else if (TREE_UNSIGNED (type) && TREE_CODE (type) != BOOLEAN_TYPE)
5541     {
5542       if (TREE_CODE (expr) == INTEGER_CST
5543           && TREE_NEGATED_INT (expr))
5544         {
5545           if (fndecl)
5546             warning ("passing negative value `%E' for %s %P of `%D'",
5547                         expr, errtype, parmnum, fndecl);
5548           else
5549             warning ("%s of negative value `%E' to `%T'",
5550                         errtype, expr, type);
5551         }
5552
5553       overflow_warning (expr);
5554
5555       if (TREE_CONSTANT (expr))
5556         expr = fold (expr);
5557     }
5558   return expr;
5559 }
5560
5561 /* Convert value RHS to type TYPE as preparation for an assignment to
5562    an lvalue of type TYPE.  ERRTYPE is a string to use in error
5563    messages: "assignment", "return", etc.  If FNDECL is non-NULL, we
5564    are doing the conversion in order to pass the PARMNUMth argument of
5565    FNDECL.  */
5566
5567 static tree
5568 convert_for_assignment (tree type, tree rhs,
5569                         const char *errtype, tree fndecl, int parmnum)
5570 {
5571   register tree rhstype;
5572   register enum tree_code coder;
5573
5574   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
5575   if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
5576     rhs = TREE_OPERAND (rhs, 0);
5577
5578   rhstype = TREE_TYPE (rhs);
5579   coder = TREE_CODE (rhstype);
5580
5581   if (TREE_CODE (type) == VECTOR_TYPE && coder == VECTOR_TYPE
5582       && ((*targetm.vector_opaque_p) (type)
5583           || (*targetm.vector_opaque_p) (rhstype)))
5584     return convert (type, rhs);
5585
5586   if (rhs == error_mark_node || rhstype == error_mark_node)
5587     return error_mark_node;
5588   if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)
5589     return error_mark_node;
5590
5591   rhs = dubious_conversion_warnings (type, rhs, errtype, fndecl, parmnum);
5592
5593   /* The RHS of an assignment cannot have void type.  */
5594   if (coder == VOID_TYPE)
5595     {
5596       error ("void value not ignored as it ought to be");
5597       return error_mark_node;
5598     }
5599
5600   /* Simplify the RHS if possible.  */
5601   if (TREE_CODE (rhs) == CONST_DECL)
5602     rhs = DECL_INITIAL (rhs);
5603
5604   /* We do not use decl_constant_value here because of this case:
5605
5606        const char* const s = "s";
5607
5608      The conversion rules for a string literal are more lax than for a
5609      variable; in particular, a string literal can be converted to a
5610      "char *" but the variable "s" cannot be converted in the same
5611      way.  If the conversion is allowed, the optimization should be
5612      performed while creating the converted expression.  */
5613
5614   /* [expr.ass]
5615
5616      The expression is implicitly converted (clause _conv_) to the
5617      cv-unqualified type of the left operand.
5618
5619      We allow bad conversions here because by the time we get to this point
5620      we are committed to doing the conversion.  If we end up doing a bad
5621      conversion, convert_like will complain.  */
5622   if (!can_convert_arg_bad (type, rhstype, rhs))
5623     {
5624       /* When -Wno-pmf-conversions is use, we just silently allow
5625          conversions from pointers-to-members to plain pointers.  If
5626          the conversion doesn't work, cp_convert will complain.  */
5627       if (!warn_pmf2ptr
5628           && TYPE_PTR_P (type)
5629           && TYPE_PTRMEMFUNC_P (rhstype))
5630         rhs = cp_convert (strip_top_quals (type), rhs);
5631       else
5632         {
5633           /* If the right-hand side has unknown type, then it is an
5634              overloaded function.  Call instantiate_type to get error
5635              messages.  */
5636           if (rhstype == unknown_type_node)
5637             instantiate_type (type, rhs, tf_error | tf_warning);
5638           else if (fndecl)
5639             error ("cannot convert `%T' to `%T' for argument `%P' to `%D'",
5640                       rhstype, type, parmnum, fndecl);
5641           else
5642             error ("cannot convert `%T' to `%T' in %s", rhstype, type,
5643                       errtype);
5644           return error_mark_node;
5645         }
5646     }
5647   return perform_implicit_conversion (strip_top_quals (type), rhs);
5648 }
5649
5650 /* Convert RHS to be of type TYPE.
5651    If EXP is nonzero, it is the target of the initialization.
5652    ERRTYPE is a string to use in error messages.
5653
5654    Two major differences between the behavior of
5655    `convert_for_assignment' and `convert_for_initialization'
5656    are that references are bashed in the former, while
5657    copied in the latter, and aggregates are assigned in
5658    the former (operator=) while initialized in the
5659    latter (X(X&)).
5660
5661    If using constructor make sure no conversion operator exists, if one does
5662    exist, an ambiguity exists.
5663
5664    If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything.  */
5665
5666 tree
5667 convert_for_initialization (tree exp, tree type, tree rhs, int flags,
5668                             const char *errtype, tree fndecl, int parmnum)
5669 {
5670   register enum tree_code codel = TREE_CODE (type);
5671   register tree rhstype;
5672   register enum tree_code coder;
5673
5674   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5675      Strip such NOP_EXPRs, since RHS is used in non-lvalue context.  */
5676   if (TREE_CODE (rhs) == NOP_EXPR
5677       && TREE_TYPE (rhs) == TREE_TYPE (TREE_OPERAND (rhs, 0))
5678       && codel != REFERENCE_TYPE)
5679     rhs = TREE_OPERAND (rhs, 0);
5680
5681   if (rhs == error_mark_node
5682       || (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node))
5683     return error_mark_node;
5684
5685   if (TREE_CODE (TREE_TYPE (rhs)) == REFERENCE_TYPE)
5686     rhs = convert_from_reference (rhs);
5687
5688   if ((TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
5689        && TREE_CODE (type) != ARRAY_TYPE
5690        && (TREE_CODE (type) != REFERENCE_TYPE
5691            || TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE))
5692       || (TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE
5693           && (TREE_CODE (type) != REFERENCE_TYPE
5694               || TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE))
5695       || TREE_CODE (TREE_TYPE (rhs)) == METHOD_TYPE)
5696     rhs = decay_conversion (rhs);
5697
5698   rhstype = TREE_TYPE (rhs);
5699   coder = TREE_CODE (rhstype);
5700
5701   if (coder == ERROR_MARK)
5702     return error_mark_node;
5703
5704   /* We accept references to incomplete types, so we can
5705      return here before checking if RHS is of complete type.  */
5706
5707   if (codel == REFERENCE_TYPE)
5708     {
5709       /* This should eventually happen in convert_arguments.  */
5710       int savew = 0, savee = 0;
5711
5712       if (fndecl)
5713         savew = warningcount, savee = errorcount;
5714       rhs = initialize_reference (type, rhs, /*decl=*/NULL_TREE,
5715                                   /*cleanup=*/NULL);
5716       if (fndecl)
5717         {
5718           if (warningcount > savew)
5719             cp_warning_at ("in passing argument %P of `%+D'", parmnum, fndecl);
5720           else if (errorcount > savee)
5721             cp_error_at ("in passing argument %P of `%+D'", parmnum, fndecl);
5722         }
5723       return rhs;
5724     }
5725
5726   if (exp != 0)
5727     exp = require_complete_type (exp);
5728   if (exp == error_mark_node)
5729     return error_mark_node;
5730
5731   rhstype = non_reference (rhstype);
5732
5733   type = complete_type (type);
5734
5735   if (IS_AGGR_TYPE (type))
5736     return ocp_convert (type, rhs, CONV_IMPLICIT|CONV_FORCE_TEMP, flags);
5737
5738   return convert_for_assignment (type, rhs, errtype, fndecl, parmnum);
5739 }
5740 \f
5741 /* Expand an ASM statement with operands, handling output operands
5742    that are not variables or INDIRECT_REFS by transforming such
5743    cases into cases that expand_asm_operands can handle.
5744
5745    Arguments are same as for expand_asm_operands.
5746
5747    We don't do default conversions on all inputs, because it can screw
5748    up operands that are expected to be in memory.  */
5749
5750 void
5751 c_expand_asm_operands (tree string, tree outputs, tree inputs, tree clobbers,
5752                        int vol, const char *filename, int line)
5753 {
5754   int noutputs = list_length (outputs);
5755   register int i;
5756   /* o[I] is the place that output number I should be written.  */
5757   register tree *o = alloca (noutputs * sizeof (tree));
5758   register tree tail;
5759
5760   /* Record the contents of OUTPUTS before it is modified.  */
5761   for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
5762     o[i] = TREE_VALUE (tail);
5763
5764   /* Generate the ASM_OPERANDS insn;
5765      store into the TREE_VALUEs of OUTPUTS some trees for
5766      where the values were actually stored.  */
5767   expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line);
5768
5769   /* Copy all the intermediate outputs into the specified outputs.  */
5770   for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
5771     {
5772       if (o[i] != TREE_VALUE (tail))
5773         {
5774           expand_expr (build_modify_expr (o[i], NOP_EXPR, TREE_VALUE (tail)),
5775                        const0_rtx, VOIDmode, EXPAND_NORMAL);
5776           free_temp_slots ();
5777
5778           /* Restore the original value so that it's correct the next
5779              time we expand this function.  */
5780           TREE_VALUE (tail) = o[i];
5781         }
5782       /* Detect modification of read-only values.
5783          (Otherwise done by build_modify_expr.)  */
5784       else
5785         {
5786           tree type = TREE_TYPE (o[i]);
5787           if (type != error_mark_node
5788               && (CP_TYPE_CONST_P (type)
5789                   || (CLASS_TYPE_P (type) && C_TYPE_FIELDS_READONLY (type))))
5790             readonly_error (o[i], "modification by `asm'", 1);
5791         }
5792     }
5793
5794   /* Those MODIFY_EXPRs could do autoincrements.  */
5795   emit_queue ();
5796 }
5797 \f
5798 /* If RETVAL is the address of, or a reference to, a local variable or
5799    temporary give an appropriate warning.  */
5800
5801 static void
5802 maybe_warn_about_returning_address_of_local (tree retval)
5803 {
5804   tree valtype = TREE_TYPE (DECL_RESULT (current_function_decl));
5805   tree whats_returned = retval;
5806
5807   for (;;)
5808     {
5809       if (TREE_CODE (whats_returned) == COMPOUND_EXPR)
5810         whats_returned = TREE_OPERAND (whats_returned, 1);
5811       else if (TREE_CODE (whats_returned) == CONVERT_EXPR
5812                || TREE_CODE (whats_returned) == NON_LVALUE_EXPR
5813                || TREE_CODE (whats_returned) == NOP_EXPR)
5814         whats_returned = TREE_OPERAND (whats_returned, 0);
5815       else
5816         break;
5817     }
5818
5819   if (TREE_CODE (whats_returned) != ADDR_EXPR)
5820     return;
5821   whats_returned = TREE_OPERAND (whats_returned, 0);
5822
5823   if (TREE_CODE (valtype) == REFERENCE_TYPE)
5824     {
5825       if (TREE_CODE (whats_returned) == AGGR_INIT_EXPR
5826           || TREE_CODE (whats_returned) == TARGET_EXPR)
5827         {
5828           warning ("returning reference to temporary");
5829           return;
5830         }
5831       if (TREE_CODE (whats_returned) == VAR_DECL
5832           && DECL_NAME (whats_returned)
5833           && TEMP_NAME_P (DECL_NAME (whats_returned)))
5834         {
5835           warning ("reference to non-lvalue returned");
5836           return;
5837         }
5838     }
5839
5840   if (TREE_CODE (whats_returned) == VAR_DECL
5841       && DECL_NAME (whats_returned)
5842       && DECL_FUNCTION_SCOPE_P (whats_returned)
5843       && !(TREE_STATIC (whats_returned)
5844            || TREE_PUBLIC (whats_returned)))
5845     {
5846       if (TREE_CODE (valtype) == REFERENCE_TYPE)
5847         cp_warning_at ("reference to local variable `%D' returned",
5848                        whats_returned);
5849       else
5850         cp_warning_at ("address of local variable `%D' returned",
5851                        whats_returned);
5852       return;
5853     }
5854 }
5855
5856 /* Check that returning RETVAL from the current function is valid.
5857    Return an expression explicitly showing all conversions required to
5858    change RETVAL into the function return type, and to assign it to
5859    the DECL_RESULT for the function.  */
5860
5861 tree
5862 check_return_expr (tree retval)
5863 {
5864   tree result;
5865   /* The type actually returned by the function, after any
5866      promotions.  */
5867   tree valtype;
5868   int fn_returns_value_p;
5869
5870   /* A `volatile' function is one that isn't supposed to return, ever.
5871      (This is a G++ extension, used to get better code for functions
5872      that call the `volatile' function.)  */
5873   if (TREE_THIS_VOLATILE (current_function_decl))
5874     warning ("function declared `noreturn' has a `return' statement");
5875
5876   /* Check for various simple errors.  */
5877   if (DECL_DESTRUCTOR_P (current_function_decl))
5878     {
5879       if (retval)
5880         error ("returning a value from a destructor");
5881       return NULL_TREE;
5882     }
5883   else if (DECL_CONSTRUCTOR_P (current_function_decl))
5884     {
5885       if (in_function_try_handler)
5886         /* If a return statement appears in a handler of the
5887            function-try-block of a constructor, the program is ill-formed.  */
5888         error ("cannot return from a handler of a function-try-block of a constructor");
5889       else if (retval)
5890         /* You can't return a value from a constructor.  */
5891         error ("returning a value from a constructor");
5892       return NULL_TREE;
5893     }
5894
5895   if (processing_template_decl)
5896     {
5897       current_function_returns_value = 1;
5898       return retval;
5899     }
5900
5901   /* When no explicit return-value is given in a function with a named
5902      return value, the named return value is used.  */
5903   result = DECL_RESULT (current_function_decl);
5904   valtype = TREE_TYPE (result);
5905   my_friendly_assert (valtype != NULL_TREE, 19990924);
5906   fn_returns_value_p = !VOID_TYPE_P (valtype);
5907   if (!retval && DECL_NAME (result) && fn_returns_value_p)
5908     retval = result;
5909
5910   /* Check for a return statement with no return value in a function
5911      that's supposed to return a value.  */
5912   if (!retval && fn_returns_value_p)
5913     {
5914       pedwarn ("return-statement with no value, in function returning '%T'",
5915                valtype);
5916       /* Clear this, so finish_function won't say that we reach the
5917          end of a non-void function (which we don't, we gave a
5918          return!).  */
5919       current_function_returns_null = 0;
5920     }
5921   /* Check for a return statement with a value in a function that
5922      isn't supposed to return a value.  */
5923   else if (retval && !fn_returns_value_p)
5924     {
5925       if (VOID_TYPE_P (TREE_TYPE (retval)))
5926         /* You can return a `void' value from a function of `void'
5927            type.  In that case, we have to evaluate the expression for
5928            its side-effects.  */
5929           finish_expr_stmt (retval);
5930       else
5931         pedwarn ("return-statement with a value, in function "
5932                  "returning 'void'");
5933
5934       current_function_returns_null = 1;
5935
5936       /* There's really no value to return, after all.  */
5937       return NULL_TREE;
5938     }
5939   else if (!retval)
5940     /* Remember that this function can sometimes return without a
5941        value.  */
5942     current_function_returns_null = 1;
5943   else
5944     /* Remember that this function did return a value.  */
5945     current_function_returns_value = 1;
5946
5947   /* Only operator new(...) throw(), can return NULL [expr.new/13].  */
5948   if ((DECL_OVERLOADED_OPERATOR_P (current_function_decl) == NEW_EXPR
5949        || DECL_OVERLOADED_OPERATOR_P (current_function_decl) == VEC_NEW_EXPR)
5950       && !TYPE_NOTHROW_P (TREE_TYPE (current_function_decl))
5951       && ! flag_check_new
5952       && null_ptr_cst_p (retval))
5953     warning ("`operator new' must not return NULL unless it is declared `throw()' (or -fcheck-new is in effect)");
5954
5955   /* Effective C++ rule 15.  See also start_function.  */
5956   if (warn_ecpp
5957       && DECL_NAME (current_function_decl) == ansi_assopname(NOP_EXPR)
5958       && retval != current_class_ref)
5959     warning ("`operator=' should return a reference to `*this'");
5960
5961   /* The fabled Named Return Value optimization, as per [class.copy]/15:
5962
5963      [...]      For  a function with a class return type, if the expression
5964      in the return statement is the name of a local  object,  and  the  cv-
5965      unqualified  type  of  the  local  object  is the same as the function
5966      return type, an implementation is permitted to omit creating the  tem-
5967      porary  object  to  hold  the function return value [...]
5968
5969      So, if this is a value-returning function that always returns the same
5970      local variable, remember it.
5971
5972      It might be nice to be more flexible, and choose the first suitable
5973      variable even if the function sometimes returns something else, but
5974      then we run the risk of clobbering the variable we chose if the other
5975      returned expression uses the chosen variable somehow.  And people expect
5976      this restriction, anyway.  (jason 2000-11-19)
5977
5978      See finish_function, genrtl_start_function, and declare_return_variable
5979      for other pieces of this optimization.  */
5980
5981   if (fn_returns_value_p && flag_elide_constructors)
5982     {
5983       if (retval != NULL_TREE
5984           && (current_function_return_value == NULL_TREE
5985               || current_function_return_value == retval)
5986           && TREE_CODE (retval) == VAR_DECL
5987           && DECL_CONTEXT (retval) == current_function_decl
5988           && ! TREE_STATIC (retval)
5989           && (DECL_ALIGN (retval)
5990               >= DECL_ALIGN (DECL_RESULT (current_function_decl)))
5991           && same_type_p ((TYPE_MAIN_VARIANT
5992                            (TREE_TYPE (retval))),
5993                           (TYPE_MAIN_VARIANT
5994                            (TREE_TYPE (TREE_TYPE (current_function_decl))))))
5995         current_function_return_value = retval;
5996       else
5997         current_function_return_value = error_mark_node;
5998     }
5999
6000   /* We don't need to do any conversions when there's nothing being
6001      returned.  */
6002   if (!retval || retval == error_mark_node)
6003     return retval;
6004
6005   /* Do any required conversions.  */
6006   if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl))
6007     /* No conversions are required.  */
6008     ;
6009   else
6010     {
6011       /* The type the function is declared to return.  */
6012       tree functype = TREE_TYPE (TREE_TYPE (current_function_decl));
6013
6014       /* First convert the value to the function's return type, then
6015          to the type of return value's location to handle the
6016          case that functype is smaller than the valtype.  */
6017       retval = convert_for_initialization
6018         (NULL_TREE, functype, retval, LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING,
6019          "return", NULL_TREE, 0);
6020       retval = convert (valtype, retval);
6021
6022       /* If the conversion failed, treat this just like `return;'.  */
6023       if (retval == error_mark_node)
6024         return retval;
6025       /* We can't initialize a register from a AGGR_INIT_EXPR.  */
6026       else if (! current_function_returns_struct
6027                && TREE_CODE (retval) == TARGET_EXPR
6028                && TREE_CODE (TREE_OPERAND (retval, 1)) == AGGR_INIT_EXPR)
6029         retval = build (COMPOUND_EXPR, TREE_TYPE (retval), retval,
6030                         TREE_OPERAND (retval, 0));
6031       else
6032         maybe_warn_about_returning_address_of_local (retval);
6033     }
6034
6035   /* Actually copy the value returned into the appropriate location.  */
6036   if (retval && retval != result)
6037     retval = build (INIT_EXPR, TREE_TYPE (result), result, retval);
6038
6039   return retval;
6040 }
6041
6042 \f
6043 /* Returns nonzero if the pointer-type FROM can be converted to the
6044    pointer-type TO via a qualification conversion.  If CONSTP is -1,
6045    then we return nonzero if the pointers are similar, and the
6046    cv-qualification signature of FROM is a proper subset of that of TO.
6047
6048    If CONSTP is positive, then all outer pointers have been
6049    const-qualified.  */
6050
6051 static int
6052 comp_ptr_ttypes_real (tree to, tree from, int constp)
6053 {
6054   bool to_more_cv_qualified = false;
6055
6056   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6057     {
6058       if (TREE_CODE (to) != TREE_CODE (from))
6059         return 0;
6060
6061       if (TREE_CODE (from) == OFFSET_TYPE
6062           && !same_type_p (TYPE_OFFSET_BASETYPE (from),
6063                            TYPE_OFFSET_BASETYPE (to)))
6064         return 0;
6065
6066       /* Const and volatile mean something different for function types,
6067          so the usual checks are not appropriate.  */
6068       if (TREE_CODE (to) != FUNCTION_TYPE && TREE_CODE (to) != METHOD_TYPE)
6069         {
6070           if (!at_least_as_qualified_p (to, from))
6071             return 0;
6072
6073           if (!at_least_as_qualified_p (from, to))
6074             {
6075               if (constp == 0)
6076                 return 0;
6077               to_more_cv_qualified = true;
6078             }
6079
6080           if (constp > 0)
6081             constp &= TYPE_READONLY (to);
6082         }
6083
6084       if (TREE_CODE (to) != POINTER_TYPE && !TYPE_PTRMEM_P (to))
6085         return ((constp >= 0 || to_more_cv_qualified)
6086                 && same_type_ignoring_top_level_qualifiers_p (to, from));
6087     }
6088 }
6089
6090 /* When comparing, say, char ** to char const **, this function takes
6091    the 'char *' and 'char const *'.  Do not pass non-pointer/reference
6092    types to this function.  */
6093
6094 int
6095 comp_ptr_ttypes (tree to, tree from)
6096 {
6097   return comp_ptr_ttypes_real (to, from, 1);
6098 }
6099
6100 /* Returns 1 if to and from are (possibly multi-level) pointers to the same
6101    type or inheritance-related types, regardless of cv-quals.  */
6102
6103 int
6104 ptr_reasonably_similar (tree to, tree from)
6105 {
6106   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6107     {
6108       /* Any target type is similar enough to void.  */
6109       if (TREE_CODE (to) == VOID_TYPE
6110           || TREE_CODE (from) == VOID_TYPE)
6111         return 1;
6112
6113       if (TREE_CODE (to) != TREE_CODE (from))
6114         return 0;
6115
6116       if (TREE_CODE (from) == OFFSET_TYPE
6117           && comptypes (TYPE_OFFSET_BASETYPE (to),
6118                         TYPE_OFFSET_BASETYPE (from),
6119                         COMPARE_BASE | COMPARE_DERIVED))
6120         continue;
6121
6122       if (TREE_CODE (to) == INTEGER_TYPE
6123           && TYPE_PRECISION (to) == TYPE_PRECISION (from))
6124         return 1;
6125
6126       if (TREE_CODE (to) == FUNCTION_TYPE)
6127         return 1;
6128
6129       if (TREE_CODE (to) != POINTER_TYPE)
6130         return comptypes
6131           (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from),
6132            COMPARE_BASE | COMPARE_DERIVED);
6133     }
6134 }
6135
6136 /* Like comp_ptr_ttypes, for const_cast.  */
6137
6138 static int
6139 comp_ptr_ttypes_const (tree to, tree from)
6140 {
6141   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
6142     {
6143       if (TREE_CODE (to) != TREE_CODE (from))
6144         return 0;
6145
6146       if (TREE_CODE (from) == OFFSET_TYPE
6147           && same_type_p (TYPE_OFFSET_BASETYPE (from),
6148                           TYPE_OFFSET_BASETYPE (to)))
6149           continue;
6150
6151       if (TREE_CODE (to) != POINTER_TYPE)
6152         return same_type_ignoring_top_level_qualifiers_p (to, from);
6153     }
6154 }
6155
6156 /* Returns the type qualifiers for this type, including the qualifiers on the
6157    elements for an array type.  */
6158
6159 int
6160 cp_type_quals (tree type)
6161 {
6162   type = strip_array_types (type);
6163   if (type == error_mark_node)
6164     return TYPE_UNQUALIFIED;
6165   return TYPE_QUALS (type);
6166 }
6167
6168 /* Returns nonzero if the TYPE contains a mutable member */
6169
6170 bool
6171 cp_has_mutable_p (tree type)
6172 {
6173   type = strip_array_types (type);
6174
6175   return CLASS_TYPE_P (type) && CLASSTYPE_HAS_MUTABLE (type);
6176 }
6177
6178 /* Subroutine of casts_away_constness.  Make T1 and T2 point at
6179    exemplar types such that casting T1 to T2 is casting away castness
6180    if and only if there is no implicit conversion from T1 to T2.  */
6181
6182 static void
6183 casts_away_constness_r (tree *t1, tree *t2)
6184 {
6185   int quals1;
6186   int quals2;
6187
6188   /* [expr.const.cast]
6189
6190      For multi-level pointer to members and multi-level mixed pointers
6191      and pointers to members (conv.qual), the "member" aspect of a
6192      pointer to member level is ignored when determining if a const
6193      cv-qualifier has been cast away.  */
6194   if (TYPE_PTRMEM_P (*t1))
6195     *t1 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t1));
6196   if (TYPE_PTRMEM_P (*t2))
6197     *t2 = build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (*t2));
6198
6199   /* [expr.const.cast]
6200
6201      For  two  pointer types:
6202
6203             X1 is T1cv1,1 * ... cv1,N *   where T1 is not a pointer type
6204             X2 is T2cv2,1 * ... cv2,M *   where T2 is not a pointer type
6205             K is min(N,M)
6206
6207      casting from X1 to X2 casts away constness if, for a non-pointer
6208      type T there does not exist an implicit conversion (clause
6209      _conv_) from:
6210
6211             Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N *
6212
6213      to
6214
6215             Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *.  */
6216
6217   if (TREE_CODE (*t1) != POINTER_TYPE
6218       || TREE_CODE (*t2) != POINTER_TYPE)
6219     {
6220       *t1 = cp_build_qualified_type (void_type_node,
6221                                      cp_type_quals (*t1));
6222       *t2 = cp_build_qualified_type (void_type_node,
6223                                      cp_type_quals (*t2));
6224       return;
6225     }
6226
6227   quals1 = cp_type_quals (*t1);
6228   quals2 = cp_type_quals (*t2);
6229   *t1 = TREE_TYPE (*t1);
6230   *t2 = TREE_TYPE (*t2);
6231   casts_away_constness_r (t1, t2);
6232   *t1 = build_pointer_type (*t1);
6233   *t2 = build_pointer_type (*t2);
6234   *t1 = cp_build_qualified_type (*t1, quals1);
6235   *t2 = cp_build_qualified_type (*t2, quals2);
6236 }
6237
6238 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
6239    constness.  */
6240
6241 static bool
6242 casts_away_constness (tree t1, tree t2)
6243 {
6244   if (TREE_CODE (t2) == REFERENCE_TYPE)
6245     {
6246       /* [expr.const.cast]
6247
6248          Casting from an lvalue of type T1 to an lvalue of type T2
6249          using a reference cast casts away constness if a cast from an
6250          rvalue of type "pointer to T1" to the type "pointer to T2"
6251          casts away constness.  */
6252       t1 = (TREE_CODE (t1) == REFERENCE_TYPE ? TREE_TYPE (t1) : t1);
6253       return casts_away_constness (build_pointer_type (t1),
6254                                    build_pointer_type (TREE_TYPE (t2)));
6255     }
6256
6257   if (TYPE_PTRMEM_P (t1) && TYPE_PTRMEM_P (t2))
6258     /* [expr.const.cast]
6259
6260        Casting from an rvalue of type "pointer to data member of X
6261        of type T1" to the type "pointer to data member of Y of type
6262        T2" casts away constness if a cast from an rvalue of type
6263        "pointer to T1" to the type "pointer to T2" casts away
6264        constness.  */
6265     return casts_away_constness
6266       (build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t1)),
6267        build_pointer_type (TYPE_PTRMEM_POINTED_TO_TYPE (t2)));
6268
6269   /* Casting away constness is only something that makes sense for
6270      pointer or reference types.  */
6271   if (TREE_CODE (t1) != POINTER_TYPE
6272       || TREE_CODE (t2) != POINTER_TYPE)
6273     return false;
6274
6275   /* Top-level qualifiers don't matter.  */
6276   t1 = TYPE_MAIN_VARIANT (t1);
6277   t2 = TYPE_MAIN_VARIANT (t2);
6278   casts_away_constness_r (&t1, &t2);
6279   if (!can_convert (t2, t1))
6280     return true;
6281
6282   return false;
6283 }
6284
6285 /* If T is a REFERENCE_TYPE return the type to which T refers.
6286    Otherwise, return T itself.  */
6287
6288 tree
6289 non_reference (tree t)
6290 {
6291   if (TREE_CODE (t) == REFERENCE_TYPE)
6292     t = TREE_TYPE (t);
6293   return t;
6294 }