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