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