| blob | 0cae93807107e1bbf884ea410db976951e7f664b |
1 /* Build expressions with type checking for C++ compiler.
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
4 Hacked by Michael Tiemann (tiemann@cygnus.com)
6 This file is part of GCC.
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.
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.
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, 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
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. */
61 /* Do `exp = require_complete_type (exp);' to make sure exp
62 does not have an incomplete type. (That includes void types.)
63 Returns the error_mark_node if the VALUE does not have
64 complete type when this function returns. */
66 tree
68 {
69 tree type;
76 else
82 /* First, detect a valid value with a complete type. */
88 else
90 }
92 /* Try to complete TYPE, if it is incomplete. For example, if TYPE is
93 a template instantiation, do the instantiation. Returns TYPE,
94 whether or not it could be completed, unless something goes
95 horribly wrong, in which case the error_mark_node is returned. */
97 tree
99 {
101 /* Rather than crash, we return something sure to cause an error
102 at some point. */
106 ;
108 {
113 needs_constructing
115 has_nontrivial_dtor
118 {
121 }
122 }
127 }
129 /* Like complete_type, but issue an error if the TYPE cannot be completed.
130 VALUE is used for informative diagnostics.
131 Returns NULL_TREE if the type cannot be made complete. */
133 tree
135 {
138 /* We already issued an error. */
141 {
144 }
145 else
147 }
149 /* Return truthvalue of whether type of EXP is instantiated. */
151 int
153 {
156 }
158 \f
159 /* Return the common type of two parameter lists.
160 We assume that comptypes has already been done and returned 1;
161 if that isn't so, this may crash.
163 As an optimization, free the space we allocate if the parameter
164 lists are already common. */
166 static tree
168 {
178 else
179 {
182 }
191 {
193 {
196 }
198 {
200 {
203 }
204 }
205 else
206 {
210 }
212 {
215 }
216 else
218 }
223 }
225 /* Given a type, perhaps copied for a typedef,
226 find the "original" version of it. */
227 tree
229 {
231 {
239 }
241 }
243 /* T1 and T2 are arithmetic or enumeration types. Return the type
244 that will result from the "usual arithmetic conversions" on T1 and
245 T2 as described in [expr]. */
247 tree
249 {
252 tree attributes;
254 /* FIXME: Attributes. */
264 /* In what follows, we slightly generalize the rules given in [expr] so
265 as to deal with `long long' and `complex'. First, merge the
266 attributes. */
269 /* If one type is complex, form the common type of the non-complex
270 components, then make that complex. Use T1 or T2 if it is the
271 required type. */
273 {
276 tree subtype
283 else
285 attributes);
286 }
289 {
290 /* When we get here we should have two vectors of the same size.
291 Just prefer the unsigned one if present. */
294 else
296 }
298 /* If only one is real, use it as the result. */
304 /* Perform the integral promotions. */
306 {
309 }
311 /* Both real or both integers; use the one with greater precision. */
317 /* The types are the same; no need to do anything fancy. */
322 {
323 /* If one is a sizetype, use it so size_binop doesn't blow up. */
329 /* If one is unsigned long long, then convert the other to unsigned
330 long long. */
334 attributes);
335 /* If one is a long long, and the other is an unsigned long, and
336 long long can represent all the values of an unsigned long, then
337 convert to a long long. Otherwise, convert to an unsigned long
338 long. Otherwise, if either operand is long long, convert the
339 other to long long.
341 Since we're here, we know the TYPE_PRECISION is the same;
342 therefore converting to long long cannot represent all the values
343 of an unsigned long, so we choose unsigned long long in that
344 case. */
347 {
349 ? long_long_unsigned_type_node
352 }
354 /* Go through the same procedure, but for longs. */
358 attributes);
361 {
365 }
366 /* Otherwise prefer the unsigned one. */
369 else
371 }
372 else
373 {
377 attributes);
381 attributes);
385 attributes);
387 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of
388 the standard C++ floating-point types. Logic earlier in this
389 function has already eliminated the possibility that
390 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no
391 compelling reason to choose one or the other. */
393 }
394 }
396 /* Subroutine of composite_pointer_type to implement the recursive
397 case. See that function for documentation fo the parameters. */
399 static tree
401 {
402 tree pointee1;
403 tree pointee2;
404 tree result_type;
405 tree attributes;
407 /* Determine the types pointed to by T1 and T2. */
409 {
412 }
413 else
414 {
417 }
419 /* [expr.rel]
421 Otherwise, the composite pointer type is a pointer type
422 similar (_conv.qual_) to the type of one of the operands,
423 with a cv-qualification signature (_conv.qual_) that is the
424 union of the cv-qualification signatures of the operand
425 types. */
433 else
434 {
439 }
443 /* If the original types were pointers to members, so is the
444 result. */
446 {
453 result_type);
454 }
455 else
458 /* Merge the attributes. */
461 }
463 /* Return the composite pointer type (see [expr.rel]) for T1 and T2.
464 ARG1 and ARG2 are the values with those types. The LOCATION is a
465 string describing the current location, in case an error occurs.
467 This routine also implements the computation of a common type for
468 pointers-to-members as per [expr.eq]. */
470 tree
473 {
474 tree class1;
475 tree class2;
477 /* [expr.rel]
479 If one operand is a null pointer constant, the composite pointer
480 type is the type of the other operand. */
486 /* We have:
488 [expr.rel]
490 If one of the operands has type "pointer to cv1 void*", then
491 the other has type "pointer to cv2T", and the composite pointer
492 type is "pointer to cv12 void", where cv12 is the union of cv1
493 and cv2.
495 If either type is a pointer to void, make sure it is T1. */
497 {
498 tree t;
502 }
504 /* Now, if T1 is a pointer to void, merge the qualifiers. */
506 {
507 tree attributes;
508 tree result_type;
513 result_type
518 /* Merge the attributes. */
521 }
525 {
528 }
530 /* [expr.eq] permits the application of a pointer conversion to
531 bring the pointers to a common type. */
537 {
542 t2 = (build_pointer_type
545 t1 = (build_pointer_type
547 else
548 {
552 }
553 }
554 /* [expr.eq] permits the application of a pointer-to-member
555 conversion to change the class type of one of the types. */
559 {
567 else
568 {
572 }
573 }
576 }
578 /* Return the merged type of two types.
579 We assume that comptypes has already been done and returned 1;
580 if that isn't so, this may crash.
582 This just combines attributes and default arguments; any other
583 differences would cause the two types to compare unalike. */
585 tree
587 {
590 tree attributes;
592 /* Save time if the two types are the same. */
598 /* If one type is nonsense, use the other. */
604 /* Merge the attributes. */
616 {
619 /* For two pointers, do this recursively on the target type. */
620 {
626 else
635 }
638 {
640 tree pointee;
645 pointee);
648 }
651 {
653 /* Save space: see if the result is identical to one of the args. */
658 /* Merge the element types, and have a size if either arg has one. */
659 t1 = build_cplus_array_type
662 }
665 /* Function types: prefer the one that specified arg types.
666 If both do, merge the arg types. Also merge the return types. */
667 {
673 /* Save space: see if the result is identical to one of the args. */
679 /* Simple way if one arg fails to specify argument types. */
681 {
686 }
689 {
694 }
699 }
702 {
703 /* Get this value the long way, since TYPE_METHOD_BASETYPE
704 is just the main variant of this. */
707 tree t3;
709 /* If this was a member function type, get back to the
710 original type of type member function (i.e., without
711 the class instance variable up front. */
721 }
724 /* There is no need to merge attributes into a TYPENAME_TYPE.
725 When the type is instantiated it will have whatever
726 attributes result from the instantiation. */
730 }
732 }
734 /* Return the common type of two types.
735 We assume that comptypes has already been done and returned 1;
736 if that isn't so, this may crash.
738 This is the type for the result of most arithmetic operations
739 if the operands have the given two types. */
741 tree
743 {
747 /* If one type is nonsense, bail. */
765 else
767 }
768 \f
769 /* Compare two exception specifier types for exactness or subsetness, if
770 allowed. Returns false for mismatch, true for match (same, or
771 derived and !exact).
773 [except.spec] "If a class X ... objects of class X or any class publicly
774 and unambiguously derived from X. Similarly, if a pointer type Y * ...
775 exceptions of type Y * or that are pointers to any type publicly and
776 unambiguously derived from Y. Otherwise a function only allows exceptions
777 that have the same type ..."
778 This does not mention cv qualifiers and is different to what throw
779 [except.throw] and catch [except.catch] will do. They will ignore the
780 top level cv qualifiers, and allow qualifiers in the pointer to class
781 example.
783 We implement the letter of the standard. */
785 static bool
787 {
791 {
797 {
802 }
810 }
812 }
814 /* Return true if TYPE1 and TYPE2 are equivalent exception specifiers.
815 If EXACT is false, T2 can be stricter than T1 (according to 15.4/7),
816 otherwise it must be exact. Exception lists are unordered, but
817 we've already filtered out duplicates. Most lists will be in order,
818 we should try to make use of that. */
820 bool
822 {
823 tree probe;
824 tree base;
839 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1.
840 Count how many we find, to determine exactness. For exact matching and
841 ordered T1, T2, this is an O(n) operation, otherwise its worst case is
842 O(nm). */
844 {
846 {
851 {
854 length++;
856 }
857 }
860 }
862 }
864 /* Compare the array types T1 and T2. ALLOW_REDECLARATION is true if
865 [] can match [size]. */
867 static bool
869 {
870 tree d1;
871 tree d2;
877 /* The type of the array elements must be the same. */
887 /* If one of the arrays is dimensionless, and the other has a
888 dimension, they are of different types. However, it is valid to
889 write:
891 extern int a[];
892 int a[3];
894 by [basic.link]:
896 declarations for an array object can specify
897 array types that differ by the presence or absence of a major
898 array bound (_dcl.array_). */
902 /* Check that the dimensions are the same. */
911 {
912 /* With abi-1 we do not fold non-dependent array bounds, (and
913 consequently mangle them incorrectly). We must therefore
914 fold them here, to verify the domains have the same
915 value. */
918 }
924 }
926 /* Return true if T1 and T2 are related as allowed by STRICT. STRICT
927 is a bitwise-or of the COMPARE_* flags. */
929 bool
931 {
935 /* Suppress errors caused by previously reported errors. */
941 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the
942 current instantiation. */
944 {
949 }
952 {
957 }
959 /* If either type is the internal version of sizetype, use the
960 language version. */
974 /* Different classes of types can't be compatible. */
978 /* Qualifiers must match. For array types, we will check when we
979 recur on the array element types. */
986 /* Allow for two different type nodes which have essentially the same
987 definition. Note that we already checked for equality of the type
988 qualifiers (just above). */
994 /* Compare the types. Break out if they could be the same. */
996 {
1008 /* Don't check inheritance. */
1010 /* Fall through. */
1052 /* Target types must match incl. qualifiers. */
1091 }
1093 /* If we get here, we know that from a target independent POV the
1094 types are the same. Make sure the target attributes are also
1095 the same. */
1097 }
1099 /* Returns 1 if TYPE1 is at least as qualified as TYPE2. */
1101 bool
1103 {
1107 /* All qualifiers for TYPE2 must also appear in TYPE1. */
1109 }
1111 /* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is
1112 more cv-qualified that TYPE1, and 0 otherwise. */
1114 int
1116 {
1129 }
1131 /* Returns 1 if the cv-qualification signature of TYPE1 is a proper
1132 subset of the cv-qualification signature of TYPE2, and the types
1133 are similar. Returns -1 if the other way 'round, and 0 otherwise. */
1135 int
1137 {
1142 else
1144 }
1146 /* If two types share a common base type, return that basetype.
1147 If there is not a unique most-derived base type, this function
1148 returns ERROR_MARK_NODE. */
1150 static tree
1152 {
1156 /* If one is a baseclass of another, that's good enough. */
1162 /* Otherwise, try to find a unique baseclass of TT1
1163 that is shared by TT2, and follow that down. */
1165 {
1170 {
1177 }
1178 }
1180 /* Same for TT2. */
1182 {
1187 {
1194 }
1195 }
1197 }
1198 \f
1199 /* Subroutines of `comptypes'. */
1201 /* Return true if two parameter type lists PARMS1 and PARMS2 are
1202 equivalent in the sense that functions with those parameter types
1203 can have equivalent types. The two lists must be equivalent,
1204 element by element. */
1206 bool
1208 {
1211 /* An unspecified parmlist matches any specified parmlist
1212 whose argument types don't need default promotions. */
1217 {
1218 /* If one parmlist is shorter than the other,
1219 they fail to match. */
1224 }
1226 }
1228 \f
1229 /* Process a sizeof or alignof expression where the operand is a
1230 type. */
1232 tree
1234 {
1236 tree value;
1244 {
1248 }
1256 {
1260 }
1261 else
1264 complain);
1267 }
1269 /* Process a sizeof or alignof expression where the operand is an
1270 expression. */
1272 tree
1274 {
1281 {
1287 }
1292 {
1295 }
1297 {
1301 }
1303 {
1306 }
1307 else
1311 }
1313 \f
1314 /* EXPR is being used in a context that is not a function call.
1315 Enforce:
1317 [expr.ref]
1319 The expression can be used only as the left-hand operand of a
1320 member function call.
1322 [expr.mptr.operator]
1324 If the result of .* or ->* is a function, then that result can be
1325 used only as the operand for the function call operator ().
1327 by issuing an error message if appropriate. Returns true iff EXPR
1328 violates these rules. */
1330 bool
1332 {
1334 {
1337 }
1339 }
1341 /* Perform the conversions in [expr] that apply when an lvalue appears
1342 in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and
1343 function-to-pointer conversions.
1345 In addition manifest constants are replaced by their values. */
1347 tree
1349 {
1350 tree type;
1360 {
1363 }
1367 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
1368 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */
1371 {
1374 }
1380 {
1381 tree adr;
1382 tree ptrtype;
1389 {
1393 }
1397 {
1400 }
1405 {
1410 }
1411 /* This way is better for a COMPONENT_REF since it can
1412 simplify the offset for a component. */
1415 }
1417 /* [basic.lval]: Class rvalues can have cv-qualified types; non-class
1418 rvalues always have cv-unqualified types. */
1423 }
1425 tree
1427 {
1434 }
1436 /* EXPR is an expression with an integral or enumeration type.
1437 Perform the integral promotions in [conv.prom], and return the
1438 converted value. */
1440 tree
1442 {
1443 tree type;
1444 tree promoted_type;
1452 }
1454 /* Take the address of an inline function without setting TREE_ADDRESSABLE
1455 or TREE_USED. */
1457 tree
1459 {
1464 }
1466 /* Returns nonzero iff exp is a STRING_CST or the result of applying
1467 decay_conversion to one. */
1469 int
1471 {
1472 tree t;
1483 {
1484 /* Make sure that we don't try to convert between char and wchar_t. */
1487 }
1488 else
1489 {
1490 /* Is this a string constant which has decayed to 'const char *'? */
1498 }
1500 /* This warning is not very useful, as it complains about printf. */
1505 }
1507 /* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we
1508 can, for example, use as an lvalue. This code used to be in
1509 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c'
1510 expressions, where we're dealing with aggregates. But now it's again only
1511 called from unary_complex_lvalue. The case (in particular) that led to
1512 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd
1513 get it there. */
1515 static tree
1517 {
1518 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that
1519 the first operand is always the one to be used if both operands
1520 are equal, so we know what conditional expression this used to be. */
1522 {
1523 /* The following code is incorrect if either operand side-effects. */
1526 return
1534 }
1536 return
1540 }
1542 /* Given the TYPE of an anonymous union field inside T, return the
1543 FIELD_DECL for the field. If not found return NULL_TREE. Because
1544 anonymous unions can nest, we must also search all anonymous unions
1545 that are directly reachable. */
1547 tree
1549 {
1550 tree field;
1553 {
1559 /* If we find it directly, return the field. */
1562 {
1564 }
1566 /* Otherwise, it could be nested, search harder. */
1569 {
1573 }
1574 }
1576 }
1578 /* Build an expression representing OBJECT.MEMBER. OBJECT is an
1579 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is
1580 non-NULL, it indicates the path to the base used to name MEMBER.
1581 If PRESERVE_REFERENCE is true, the expression returned will have
1582 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression
1583 returned will have the type referred to by the reference.
1585 This function does not perform access control; that is either done
1586 earlier by the parser when the name of MEMBER is resolved to MEMBER
1587 itself, or later when overload resolution selects one of the
1588 functions indicated by MEMBER. */
1590 tree
1593 {
1594 tree object_type;
1595 tree member_scope;
1603 /* [expr.ref]
1605 The type of the first expression shall be "class object" (of a
1606 complete type). */
1612 {
1616 }
1618 /* The standard does not seem to actually say that MEMBER must be a
1619 member of OBJECT_TYPE. However, that is clearly what is
1620 intended. */
1622 {
1627 }
1628 else
1630 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will
1631 presently be the anonymous union. Go outwards until we find a
1632 type related to OBJECT_TYPE. */
1635 object_type))
1638 {
1641 else
1644 }
1646 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into
1647 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue
1648 in the frontend; only _DECLs and _REFs are lvalues in the backend. */
1649 {
1653 }
1655 /* In [expr.ref], there is an explicit list of the valid choices for
1656 MEMBER. We check for each of those cases here. */
1658 {
1659 /* A static data member. */
1661 /* If OBJECT has side-effects, they are supposed to occur. */
1664 }
1666 {
1667 /* A non-static data member. */
1670 tree member_type;
1675 /* Convert OBJECT to the type of MEMBER. */
1678 {
1679 tree binfo;
1680 base_kind kind;
1687 /* It is invalid to try to get to a virtual base of a
1688 NULL object. The most common cause is invalid use of
1689 offsetof macro. */
1691 {
1694 member);
1697 }
1699 /* Convert to the base. */
1702 /* If we found the base successfully then we should be able
1703 to convert to it successfully. */
1705 }
1707 /* Complain about other invalid uses of offsetof, even though they will
1708 give the right answer. Note that we complain whether or not they
1709 actually used the offsetof macro, since there's no way to know at this
1710 point. So we just give a warning, instead of a pedwarn. */
1711 /* Do not produce this warning for base class field references, because
1712 we know for a fact that didn't come from offsetof. This does occur
1713 in various testsuite cases where a null object is passed where a
1714 vtable access is required. */
1719 {
1721 member);
1723 }
1725 /* If MEMBER is from an anonymous aggregate, we have converted
1726 OBJECT so that it refers to the class containing the
1727 anonymous union. Generate a reference to the anonymous union
1728 itself, and recur to find MEMBER. */
1730 /* When this code is called from build_field_call, the
1731 object already has the type of the anonymous union.
1732 That is because the COMPONENT_REF was already
1733 constructed, and was then disassembled before calling
1734 build_field_call. After the function-call code is
1735 cleaned up, this waste can be eliminated. */
1736 && (!same_type_ignoring_top_level_qualifiers_p
1738 {
1739 tree anonymous_union;
1744 anonymous_union,
1746 preserve_reference);
1747 }
1749 /* Compute the type of the field, as described in [expr.ref]. */
1753 {
1757 /* A field is const (volatile) if the enclosing object, or the
1758 field itself, is const (volatile). But, a mutable field is
1759 not const, even within a const object. */
1763 }
1766 NULL_TREE);
1769 /* Mark the expression const or volatile, as appropriate. Even
1770 though we've dealt with the type above, we still have to mark the
1771 expression itself. */
1776 }
1778 {
1779 /* The member is a (possibly overloaded) member function. */
1780 tree functions;
1781 tree type;
1783 /* If the MEMBER is exactly one static member function, then we
1784 know the type of the expression. Otherwise, we must wait
1785 until overload resolution has been performed. */
1790 else
1792 /* Note that we do not convert OBJECT to the BASELINK_BINFO
1793 base. That will happen when the function is called. */
1795 }
1797 {
1798 /* The member is an enumerator. */
1800 /* If OBJECT has side-effects, they are supposed to occur. */
1804 }
1805 else
1806 {
1809 }
1812 /* [expr.ref]
1814 If E2 is declared to have type "reference to T", then ... the
1815 type of E1.E2 is T. */
1819 }
1821 /* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if
1822 SCOPE is NULL, by OBJECT.~DTOR_NAME. */
1824 static tree
1826 {
1829 tree expr;
1832 {
1836 }
1838 {
1842 }
1845 expr = (adjust_result_of_qualified_name_lookup
1848 }
1850 /* An expression of the form "A::template B" has been resolved to
1851 DECL. Issue a diagnostic if B is not a template or template
1852 specialization. */
1854 void
1856 {
1857 /* The standard says:
1859 [temp.names]
1861 If a name prefixed by the keyword template is not a member
1862 template, the program is ill-formed.
1864 DR 228 removed the restriction that the template be a member
1865 template.
1867 DR 96, if accepted would add the further restriction that explicit
1868 template arguments must be provided if the template keyword is
1869 used, but, as of 2005-10-16, that DR is still in "drafting". If
1870 this DR is accepted, then the semantic checks here can be
1871 simplified, as the entity named must in fact be a template
1872 specialization, rather than, as at present, a set of overloaded
1873 functions containing at least one template function. */
1876 {
1879 else
1880 {
1881 tree fns;
1886 {
1896 }
1899 }
1900 }
1901 }
1903 /* This function is called by the parser to process a class member
1904 access expression of the form OBJECT.NAME. NAME is a node used by
1905 the parser to represent a name; it is not yet a DECL. It may,
1906 however, be a BASELINK where the BASELINK_FUNCTIONS is a
1907 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and
1908 there is no reason to do the lookup twice, so the parser keeps the
1909 BASELINK. TEMPLATE_P is true iff NAME was explicitly declared to
1910 be a template via the use of the "A::template B" syntax. */
1912 tree
1914 {
1915 tree expr;
1916 tree object_type;
1917 tree member;
1925 /* If OBJECT is an ObjC class instance, we must obey ObjC access rules. */
1932 {
1935 /* If NAME is just an IDENTIFIER_NODE, then the expression
1936 is dependent. */
1938 /* If NAME is "f<args>", where either 'f' or 'args' is
1939 dependent, then the expression is dependent. */
1943 /* If NAME is "T::X" where "T" is dependent, then the
1944 expression is dependent. */
1950 }
1952 /* [expr.ref]
1954 The type of the first expression shall be "class object" (of a
1955 complete type). */
1960 {
1964 }
1967 /* A member function that has already been looked up. */
1969 else
1970 {
1973 tree scope;
1976 {
1985 }
1988 {
1989 /* A qualified name. The qualifying class or namespace `S' has
1990 already been looked up; it is either a TYPE or a
1991 NAMESPACE_DECL. The member name is either an IDENTIFIER_NODE
1992 or a BIT_NOT_EXPR. */
2000 /* If SCOPE is a namespace, then the qualified name does not
2001 name a member of OBJECT_TYPE. */
2003 {
2007 }
2009 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */
2014 {
2017 }
2018 }
2019 else
2020 {
2023 }
2027 else
2028 {
2029 /* Look up the member. */
2033 {
2036 }
2039 }
2042 {
2047 else
2048 {
2051 }
2052 }
2053 }
2064 {
2066 {
2070 }
2073 NULL_TREE);
2074 }
2077 }
2079 /* Return an expression for the MEMBER_NAME field in the internal
2080 representation of PTRMEM, a pointer-to-member function. (Each
2081 pointer-to-member function type gets its own RECORD_TYPE so it is
2082 more convenient to access the fields by name than by FIELD_DECL.)
2083 This routine converts the NAME to a FIELD_DECL and then creates the
2084 node for the complete expression. */
2086 tree
2088 {
2089 tree ptrmem_type;
2090 tree member;
2091 tree member_type;
2093 /* This code is a stripped down version of
2094 build_class_member_access_expr. It does not work to use that
2095 routine directly because it expects the object to be of class
2096 type. */
2105 }
2107 /* Given an expression PTR for a pointer, return an expression
2108 for the value pointed to.
2109 ERRORSTRING is the name of the operator to appear in error messages.
2111 This function may need to overload OPERATOR_FNNAME.
2112 Must also handle REFERENCE_TYPEs for C++. */
2114 tree
2116 {
2118 tree rval;
2121 {
2125 }
2134 else
2136 }
2138 tree
2140 {
2154 {
2155 /* [expr.unary.op]
2157 If the type of the expression is "pointer to T," the type
2158 of the result is "T."
2160 We must use the canonical variant because certain parts of
2161 the back end, like fold, do pointer comparisons between
2162 types. */
2166 {
2167 /* A pointer to incomplete type (other than cv void) can be
2168 dereferenced [expr.unary.op]/1 */
2171 }
2174 /* The POINTER was something like `&x'. We simplify `*&x' to
2175 `x'. */
2177 else
2178 {
2181 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2182 so that we get the proper error message if the result is used
2183 to assign to. Also, &* is supposed to be a no-op. */
2189 }
2190 }
2191 /* `pointer' won't be an error_mark_node if we were given a
2192 pointer to member, so it's cool to check for this here. */
2196 {
2199 else
2201 }
2203 }
2205 /* This handles expressions of the form "a[i]", which denotes
2206 an array reference.
2208 This is logically equivalent in C to *(a+i), but we may do it differently.
2209 If A is a variable or a member, we generate a primitive ARRAY_REF.
2210 This avoids forcing the array out of registers, and can work on
2211 arrays that are not lvalues (for example, members of structures returned
2212 by functions).
2214 If INDEX is of some user-defined type, it must be converted to
2215 integer type. Otherwise, to make a compatible PLUS_EXPR, it
2216 will inherit the type of the array, which will be some pointer type. */
2218 tree
2220 {
2222 {
2225 }
2231 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference
2232 inside it. */
2234 {
2236 {
2240 }
2243 return build_conditional_expr
2250 }
2253 {
2259 {
2262 }
2264 /* Apply integral promotions *after* noticing character types.
2265 (It is unclear why we do these promotions -- the standard
2266 does not say that we should. In fact, the natural thing would
2267 seem to be to convert IDX to ptrdiff_t; we're performing
2268 pointer arithmetic.) */
2271 /* An array that is indexed by a non-constant
2272 cannot be stored in a register; we must be able to do
2273 address arithmetic on its address.
2274 Likewise an array of elements of variable size. */
2279 {
2282 }
2284 /* An array that is indexed by a constant value which is not within
2285 the array bounds cannot be stored in a register either; because we
2286 would get a crash in store_bit_field/extract_bit_field when trying
2287 to access a non-existent part of the register. */
2291 {
2294 }
2299 /* Note in C++ it is valid to subscript a `register' array, since
2300 it is valid to take the address of something with that
2301 storage specification. */
2303 {
2309 }
2313 /* Array ref is const/volatile if the array elements are
2314 or if the array is.. */
2322 }
2324 {
2328 /* Put the integer in IND to simplify error checking. */
2330 {
2334 }
2340 {
2343 }
2345 {
2348 }
2352 }
2353 }
2354 \f
2355 /* Resolve a pointer to member function. INSTANCE is the object
2356 instance to use, if the member points to a virtual member.
2358 This used to avoid checking for virtual functions if basetype
2359 has no virtual functions, according to an earlier ANSI draft.
2360 With the final ISO C++ rules, such an optimization is
2361 incorrect: A pointer to a derived member can be static_cast
2362 to pointer-to-base-member, as long as the dynamic object
2363 later has the right member. */
2365 tree
2367 {
2372 {
2379 {
2381 {
2382 /* Extracting the function address from a pmf is only
2383 allowed with -Wno-pmf-conversions. It only works for
2384 pmf constants. */
2388 }
2389 else
2390 {
2393 }
2394 }
2402 /* Start by extracting all the information from the PMF itself. */
2407 {
2420 }
2422 /* Convert down to the right base before using the instance. A
2423 special case is that in a pointer to member of class C, C may
2424 be incomplete. In that case, the function will of course be
2425 a member of C, and no conversion is required. In fact,
2426 lookup_base will fail in that case, because incomplete
2427 classes do not have BINFOs. */
2431 {
2438 }
2439 /* ...and then the delta in the PMF. */
2443 /* Hand back the adjusted 'this' argument to our caller. */
2446 /* Next extract the vtable pointer from the object. */
2448 instance_ptr);
2451 /* Finally, extract the function pointer from the vtable. */
2457 /* When using function descriptors, the address of the
2458 vtable entry is treated as a function pointer. */
2466 /* Make sure this doesn't get evaluated first inside one of the
2467 branches of the COND_EXPR. */
2473 }
2475 }
2477 tree
2479 {
2481 tree coerced_params;
2486 /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2487 expressions, like those used for ObjC messenger dispatches. */
2490 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2491 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */
2497 {
2503 /* Convert anything with function type to a pointer-to-function. */
2507 /* Differs from default_conversion by not setting TREE_ADDRESSABLE
2508 (because calling an inline function does not mean the function
2509 needs to be separately compiled). */
2513 else
2515 }
2516 else
2517 {
2521 }
2529 {
2532 original);
2534 }
2541 || is_method
2543 {
2546 }
2548 /* fntype now gets the type of function pointed to. */
2551 /* Convert the parameters to the types declared in the
2552 function prototype, or apply default promotions. */
2559 /* Check for errors in format strings and inappropriately
2560 null parameters. */
2566 }
2567 \f
2568 /* Convert the actual parameter expressions in the list VALUES
2569 to the types in the list TYPELIST.
2570 If parmdecls is exhausted, or when an element has NULL as its type,
2571 perform the default conversions.
2573 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages.
2575 This is also where warnings about wrong number of args are generated.
2577 Return a list of expressions for the parameters as converted.
2579 Both VALUES and the returned value are chains of TREE_LIST nodes
2580 with the elements of the list in the TREE_VALUE slots of those nodes.
2582 In C++, unspecified trailing parameters can be filled in with their
2583 default arguments, if such were specified. Do so here. */
2585 static tree
2587 {
2593 /* Argument passing is always copy-initialization. */
2597 {
2599 {
2603 else
2605 }
2606 else
2608 }
2611 valtail;
2613 {
2621 {
2623 {
2626 }
2627 else
2629 /* In case anybody wants to know if this argument
2630 list is valid. */
2634 }
2636 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2637 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */
2644 {
2649 }
2655 {
2656 /* Formal parm type is specified by a function prototype. */
2657 tree parmval;
2660 {
2664 else
2667 }
2668 else
2669 {
2670 parmval = convert_for_initialization
2674 }
2680 }
2681 else
2682 {
2685 /* Don't do ellipsis conversion for __built_in_constant_p
2686 as this will result in spurious warnings for non-POD
2687 types. */
2689 else
2693 }
2697 }
2700 {
2701 /* See if there are default arguments that can be used. */
2704 {
2706 {
2707 tree parmval
2717 /* ends with `...'. */
2720 }
2721 }
2722 else
2723 {
2725 {
2728 }
2729 else
2732 }
2733 }
2736 }
2737 \f
2738 /* Build a binary-operation expression, after performing default
2739 conversions on the operands. CODE is the kind of expression to build. */
2741 tree
2744 {
2745 tree orig_arg1;
2746 tree orig_arg2;
2747 tree expr;
2753 {
2759 }
2763 else
2765 overloaded_p);
2771 }
2773 /* Build a binary-operation expression without default conversions.
2774 CODE is the kind of expression to build.
2775 This function differs from `build' in several ways:
2776 the data type of the result is computed and recorded in it,
2777 warnings are generated if arg data types are invalid,
2778 special handling for addition and subtraction of pointers is known,
2779 and some optimization is done (operations on narrow ints
2780 are done in the narrower type when that gives the same result).
2781 Constant folding is also done before the result is returned.
2783 Note that the operands will never have enumeral types
2784 because either they have just had the default conversions performed
2785 or they have both just been converted to some other type in which
2786 the arithmetic is to be done.
2788 C++: must do special pointer arithmetic when implementing
2789 multiple inheritance, and deal with pointer to member functions. */
2791 tree
2794 {
2800 /* Expression code to give to the expression when it is built.
2801 Normally this is CODE, which is what the caller asked for,
2802 but in some special cases we change it. */
2805 /* Data type in which the computation is to be performed.
2806 In the simplest cases this is the common type of the arguments. */
2809 /* Nonzero means operands have already been type-converted
2810 in whatever way is necessary.
2811 Zero means they need to be converted to RESULT_TYPE. */
2814 /* Nonzero means create the expression with this type, rather than
2815 RESULT_TYPE. */
2818 /* Nonzero means after finally constructing the expression
2819 convert it to this type. */
2822 tree result;
2824 /* Nonzero if this is an operation like MIN or MAX which can
2825 safely be computed in short if both args are promoted shorts.
2826 Also implies COMMON.
2827 -1 indicates a bitwise operation; this makes a difference
2828 in the exact conditions for when it is safe to do the operation
2829 in a narrower mode. */
2832 /* Nonzero if this is a comparison operation;
2833 if both args are promoted shorts, compare the original shorts.
2834 Also implies COMMON. */
2837 /* Nonzero if this is a right-shift operation, which can be computed on the
2838 original short and then promoted if the operand is a promoted short. */
2841 /* Nonzero means set RESULT_TYPE to the common type of the args. */
2844 /* True if both operands have arithmetic type. */
2847 /* Apply default conversions. */
2854 {
2859 }
2860 else
2861 {
2866 }
2868 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
2872 /* DTRT if one side is an overloaded function, but complain about it. */
2874 {
2877 {
2881 }
2882 }
2884 {
2887 {
2891 }
2892 }
2897 /* The expression codes of the data types of the arguments tell us
2898 whether the arguments are integers, floating, pointers, etc. */
2902 /* If an error was already reported for one of the arguments,
2903 avoid reporting another error. */
2910 {
2913 }
2916 {
2918 /* Handle the pointer + int case. */
2923 else
2928 /* Subtraction of two similar pointers.
2929 We must subtract them as integers, then divide by object size. */
2934 /* Handle pointer minus int. Just like pointer plus int. */
2937 else
2954 {
2967 else
2968 /* When dividing two signed integers, we have to promote to int.
2969 unless we divide by a constant != -1. Note that default
2970 conversion will have been performed on the operands at this
2971 point, so we have to dig out the original type to find out if
2972 it was unsigned. */
2979 }
2998 {
2999 /* Although it would be tempting to shorten always here, that loses
3000 on some targets, since the modulo instruction is undefined if the
3001 quotient can't be represented in the computation mode. We shorten
3002 only if unsigned or if dividing by something we know != -1. */
3008 }
3018 /* Shift operations: result has same type as first operand;
3019 always convert second operand to int.
3020 Also set SHORT_SHIFT if shifting rightward. */
3024 {
3027 {
3030 else
3031 {
3036 }
3037 }
3038 /* Convert the shift-count to an integer, regardless of
3039 size of value being shifted. */
3042 /* Avoid converting op1 to result_type later. */
3044 }
3049 {
3052 {
3057 }
3058 /* Convert the shift-count to an integer, regardless of
3059 size of value being shifted. */
3062 /* Avoid converting op1 to result_type later. */
3064 }
3070 {
3073 {
3080 }
3081 /* Convert the shift-count to an integer, regardless of
3082 size of value being shifted. */
3085 }
3114 {
3117 }
3119 {
3122 }
3124 {
3128 }
3133 {
3134 /* E will be the final comparison. */
3135 tree e;
3136 /* E1 and E2 are for scratch. */
3137 tree e1;
3138 tree e2;
3139 tree pfn0;
3140 tree pfn1;
3141 tree delta0;
3142 tree delta1;
3149 /* We generate:
3151 (op0.pfn == op1.pfn
3152 && (!op0.pfn || op0.delta == op1.delta))
3154 The reason for the `!op0.pfn' bit is that a NULL
3155 pointer-to-member is any member with a zero PFN; the
3156 DELTA field is unspecified. */
3160 delta_identifier);
3162 delta_identifier);
3165 pfn0,
3167 integer_zero_node));
3174 }
3175 else
3176 {
3179 type1));
3182 type0));
3183 }
3220 {
3223 }
3225 {
3228 }
3240 {
3243 }
3249 }
3255 else
3256 {
3258 /* Vector arithmetic is only allowed when both sides are vectors. */
3260 {
3264 {
3267 }
3269 }
3270 }
3271 /* Determine the RESULT_TYPE, if it is not already known. */
3273 && arithmetic_types_p
3278 {
3282 }
3284 /* If we're in a template, the only thing we need to know is the
3285 RESULT_TYPE. */
3292 {
3295 /* For certain operations (which identify themselves by shorten != 0)
3296 if both args were extended from the same smaller type,
3297 do the arithmetic in that type and then extend.
3299 shorten !=0 and !=1 indicates a bitwise operation.
3300 For them, this optimization is safe only if
3301 both args are zero-extended or both are sign-extended.
3302 Otherwise, we might change the result.
3303 Eg, (short)-1 | (unsigned short)-1 is (int)-1
3304 but calculated in (unsigned short) it would be (unsigned short)-1. */
3307 {
3311 /* UNS is 1 if the operation to be done is an unsigned one. */
3313 tree type;
3317 /* Handle the case that OP0 does not *contain* a conversion
3318 but it *requires* conversion to FINAL_TYPE. */
3325 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */
3327 /* For bitwise operations, signedness of nominal type
3328 does not matter. Consider only how operands were extended. */
3332 /* Note that in all three cases below we refrain from optimizing
3333 an unsigned operation on sign-extended args.
3334 That would not be valid. */
3336 /* Both args variable: if both extended in same way
3337 from same width, do it in that width.
3338 Do it unsigned if args were zero-extended. */
3345 result_type = c_common_signed_or_unsigned_type
3363 }
3365 /* Shifts can be shortened if shifting right. */
3368 {
3378 /* We can shorten only if the shift count is less than the
3379 number of bits in the smaller type size. */
3381 /* If arg is sign-extended and then unsigned-shifted,
3382 we can simulate this with a signed shift in arg's type
3383 only if the extended result is at least twice as wide
3384 as the arg. Otherwise, the shift could use up all the
3385 ones made by sign-extension and bring in zeros.
3386 We can't optimize that case at all, but in most machines
3387 it never happens because available widths are 2**N. */
3389 || unsigned_arg
3392 {
3393 /* Do an unsigned shift if the operand was zero-extended. */
3394 result_type
3397 /* Convert value-to-be-shifted to that type. */
3401 }
3402 }
3404 /* Comparison operations are shortened too but differently.
3405 They identify themselves by setting short_compare = 1. */
3408 {
3409 /* Don't write &op0, etc., because that would prevent op0
3410 from being kept in a register.
3411 Instead, make copies of the our local variables and
3412 pass the copies by reference, then copy them back afterward. */
3415 tree val
3422 }
3425 && warn_sign_compare
3426 /* Do not warn until the template is instantiated; we cannot
3427 bound the ranges of the arguments until that point. */
3429 {
3437 /* Check for comparison of different enum types. */
3442 {
3445 }
3447 /* Give warnings for comparisons between signed and unsigned
3448 quantities that may fail. */
3449 /* Do the checking based on the original operand trees, so that
3450 casts will be considered, but default promotions won't be. */
3452 /* Do not warn if the comparison is being done in a signed type,
3453 since the signed type will only be chosen if it can represent
3454 all the values of the unsigned type. */
3457 /* Do not warn if both operands are unsigned. */
3460 /* Do not warn if the signed quantity is an unsuffixed
3461 integer literal (or some static constant expression
3462 involving such literals or a conditional expression
3463 involving such literals) and it is non-negative. */
3467 /* Do not warn if the comparison is an equality operation,
3468 the unsigned quantity is an integral constant and it does
3469 not use the most significant bit of result_type. */
3478 else
3481 /* Warn if two unsigned values are being compared in a size
3482 larger than their original size, and one (and only one) is the
3483 result of a `~' operator. This comparison will always fail.
3485 Also warn if one operand is a constant, and the constant does not
3486 have all bits set that are set in the ~ operand when it is
3487 extended. */
3491 {
3498 {
3499 tree primop;
3505 {
3509 }
3510 else
3511 {
3515 }
3520 {
3524 }
3525 }
3532 }
3533 }
3534 }
3536 /* If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
3537 Then the expression will be built.
3538 It will be given type FINAL_TYPE if that is nonzero;
3539 otherwise, it will be given type RESULT_TYPE. */
3541 /* Issue warnings about peculiar, but valid, uses of NULL. */
3543 and ||, so NULL is no exception. */
3548 /* Or vice versa. */
3551 /* Or, both are NULL and the operation was not a comparison. */
3554 /* Some sort of arithmetic operation involving NULL was
3555 performed. Note that pointer-difference and pointer-addition
3556 have already been handled above, and so we don't end up here in
3557 that case. */
3561 {
3569 }
3579 }
3580 \f
3581 /* Return a tree for the sum or difference (RESULTCODE says which)
3582 of pointer PTROP and integer INTOP. */
3584 static tree
3586 {
3589 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type)
3590 in certain circumstance (when it's valid to do so). So we need
3591 to make sure it's complete. We don't need to check here, if we
3592 can actually complete it at all, as those checks will be done in
3593 pointer_int_sum() anyway. */
3598 }
3600 /* Return a tree for the difference of pointers OP0 and OP1.
3601 The resulting tree has type int. */
3603 static tree
3605 {
3606 tree result;
3614 {
3621 }
3623 /* First do the subtraction as integers;
3624 then drop through to build the divide operator. */
3630 /* This generates an error if op1 is a pointer to an incomplete type. */
3638 /* Do the division. */
3642 }
3643 \f
3644 /* Construct and perhaps optimize a tree representation
3645 for a unary operation. CODE, a tree_code, specifies the operation
3646 and XARG is the operand. */
3648 tree
3650 {
3652 tree exp;
3656 {
3661 }
3665 /* [expr.unary.op] says:
3667 The address of an object of incomplete type can be taken.
3669 (And is just the ordinary address operator, not an overloaded
3670 "operator &".) However, if the type is a template
3671 specialization, we must complete the type at this point so that
3672 an overloaded "operator &" will be available if required. */
3679 else
3683 {
3684 /* A pointer to member-function can be formed only by saying
3685 &X::mf. */
3688 {
3691 {
3693 xarg);
3697 }
3698 else
3699 {
3702 xarg);
3704 }
3705 }
3708 {
3713 {
3714 /* A single non-static member, make sure we don't allow a
3715 pointer-to-member. */
3720 }
3721 }
3725 }
3733 }
3735 /* Like c_common_truthvalue_conversion, but handle pointer-to-member
3736 constants, where a null value is represented by an INTEGER_CST of
3737 -1. */
3739 tree
3741 {
3745 else
3747 }
3749 /* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */
3751 tree
3753 {
3754 tree t;
3760 }
3762 /* Return an ADDR_EXPR giving the address of T. This function
3763 attempts no optimizations or simplifications; it is a low-level
3764 primitive. */
3766 tree
3768 {
3769 tree addr;
3777 }
3779 /* Return a NOP_EXPR converting EXPR to TYPE. */
3781 tree
3783 {
3787 }
3789 /* C++: Must handle pointers to members.
3791 Perhaps type instantiation should be extended to handle conversion
3792 from aggregates to types we don't yet know we want? (Or are those
3793 cases typically errors which should be reported?)
3795 NOCONVERT nonzero suppresses the default promotions
3796 (such as from short to int). */
3798 tree
3800 {
3801 /* No default_conversion here. It causes trouble for ADDR_EXPR. */
3805 tree val;
3813 ? CONVERT_EXPR
3816 {
3819 }
3822 {
3825 {
3827 /* Unary plus (but not unary minus) is allowed on pointers. */
3835 else
3836 {
3840 /* Make sure the result is not an lvalue: a unary plus or minus
3841 expression is always a rvalue. */
3843 }
3844 }
3849 {
3853 }
3869 /* Conjugating a real value is a no-op, but allow it anyway. */
3891 {
3894 }
3895 else
3902 {
3905 }
3906 else
3913 /* Handle complex lvalues (when permitted)
3914 by reduction to simpler cases. */
3920 /* Increment or decrement the real part of the value,
3921 and don't change the imaginary part. */
3923 {
3931 }
3933 /* Report invalid types. */
3937 {
3944 else
3947 }
3949 /* Report something read-only. */
3958 {
3959 tree inc;
3965 /* ARM $5.2.5 last annotation says this should be forbidden. */
3971 /* Compute the increment. */
3974 {
3989 }
3990 else
3995 /* Handle incrementing a cast-expression. */
3998 {
4006 {
4013 else
4024 /* Eliminate warning about unused result of + or -. */
4027 }
4031 }
4033 /* Complain about anything else that is not a true lvalue. */
4039 /* Forbid using -- on `bool'. */
4041 {
4043 {
4046 }
4048 }
4049 else
4054 }
4057 /* Note that this operation never does default_conversion
4058 regardless of NOCONVERT. */
4066 {
4070 }
4072 /* ARM $3.4 */
4075 /* Let &* cancel out to simplify resulting code. */
4077 {
4078 /* We don't need to have `current_class_ptr' wrapped in a
4079 NON_LVALUE_EXPR node. */
4085 {
4088 }
4089 else
4090 /* Don't let this be an lvalue. */
4093 }
4095 /* Uninstantiated types are all functions. Taking the
4096 address of a function is a no-op, so just return the
4097 argument. */
4104 {
4105 /* They're trying to take the address of a unique non-static
4106 member function. This is ill-formed (except in MS-land),
4107 but let's try to DTRT.
4108 Note: We only handle unique functions here because we don't
4109 want to complain if there's a static overload; non-unique
4110 cases will be handled by instantiate_type. But we need to
4111 handle this case here to allow casts on the resulting PMF.
4112 We could defer this in non-MS mode, but it's easier to give
4113 a useful error here. */
4115 /* Inside constant member functions, the `this' pointer
4116 contains an extra const qualifier. TYPE_MAIN_VARIANT
4117 is used here to remove this const from the diagnostics
4118 and the created OFFSET_REF. */
4123 {
4126 /* An expression like &memfn. */
4128 " or parenthesized non-static member function to form"
4131 else
4133 " function to form a pointer to member function."
4136 }
4138 }
4140 offset_ref:
4144 /* Handle complex lvalues (when permitted)
4145 by reduction to simpler cases. */
4151 {
4168 /* Turn a reference to a non-static data member into a
4169 pointer-to-member. */
4170 {
4171 tree type;
4172 tree t;
4179 {
4182 }
4188 }
4192 }
4194 /* Allow the address of a constructor if all the elements
4195 are constant. */
4198 ;
4199 /* Anything not already handled and not a true memory reference
4200 is an error. */
4210 {
4211 tree addr;
4214 /* Inside a template, we are processing a non-dependent
4215 expression so we can just form an ADDR_EXPR with the
4216 correct type. */
4218 {
4222 }
4224 {
4227 /* We can only get here with a single static member
4228 function. */
4234 /* Do not lose object's side effects. */
4237 }
4239 {
4243 }
4244 else
4245 {
4251 }
4255 {
4259 }
4262 }
4266 }
4269 {
4273 }
4277 }
4279 /* Apply unary lvalue-demanding operator CODE to the expression ARG
4280 for certain kinds of expressions which are not really lvalues
4281 but which we can accept as lvalues.
4283 If ARG is not a kind of expression we can handle, return
4284 NULL_TREE. */
4286 tree
4288 {
4289 /* Inside a template, making these kinds of adjustments is
4290 pointless; we are only concerned with the type of the
4291 expression. */
4295 /* Handle (a, b) used as an "lvalue". */
4297 {
4301 }
4303 /* Handle (a ? b : c) used as an "lvalue". */
4308 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */
4312 {
4315 {
4319 }
4320 return unary_complex_lvalue
4322 }
4327 /* Handle (a = b) used as an "lvalue" for `&'. */
4330 {
4336 }
4343 /* We permit compiler to make function calls returning
4344 objects of aggregate type look like lvalues. */
4345 {
4352 {
4355 else
4358 }
4363 }
4365 /* Don't let anything else be handled specially. */
4367 }
4368 \f
4369 /* Mark EXP saying that we need to be able to take the
4370 address of it; it should not be allocated in a register.
4371 Value is true if successful.
4373 C++: we do not allow `current_class_ptr' to be addressable. */
4375 bool
4377 {
4382 {
4393 {
4397 }
4398 /* Fall through. */
4401 /* Caller should not be trying to mark initialized
4402 constant fields addressable. */
4407 /* Fall through. */
4413 {
4415 {
4416 error
4419 }
4421 warning
4423 }
4442 }
4443 }
4444 \f
4445 /* Build and return a conditional expression IFEXP ? OP1 : OP2. */
4447 tree
4449 {
4453 tree expr;
4456 {
4457 /* The standard says that the expression is type-dependent if
4458 IFEXP is type-dependent, even though the eventual type of the
4459 expression doesn't dependent on IFEXP. */
4461 /* As a GNU extension, the middle operand may be omitted. */
4469 }
4476 }
4477 \f
4478 /* Given a list of expressions, return a compound expression
4479 that performs them all and returns the value of the last of them. */
4482 {
4486 {
4492 }
4495 }
4497 /* Handle overloading of the ',' operator when needed. */
4499 tree
4501 {
4502 tree result;
4507 {
4513 }
4524 }
4526 /* Build a compound expression. */
4528 tree
4530 {
4537 {
4538 /* If the rhs is a TARGET_EXPR, then build the compound
4539 expression inside the target_expr's initializer. This
4540 helps the compiler to eliminate unnecessary temporaries. */
4547 }
4550 }
4552 /* Issue a diagnostic message if casting from SRC_TYPE to DEST_TYPE
4553 casts away constness. DIAG_FN gives the function to call if we
4554 need to issue a diagnostic; if it is NULL, no diagnostic will be
4555 issued. DESCRIPTION explains what operation is taking place. */
4557 static void
4561 {
4565 }
4567 /* Convert EXPR (an expression with pointer-to-member type) to TYPE
4568 (another pointer-to-member type in the same hierarchy) and return
4569 the converted expression. If ALLOW_INVERSE_P is permitted, a
4570 pointer-to-derived may be converted to pointer-to-base; otherwise,
4571 only the other direction is permitted. If C_CAST_P is true, this
4572 conversion is taking place as part of a C-style cast. */
4574 tree
4577 {
4579 {
4580 tree delta;
4586 allow_inverse_p,
4587 c_cast_p);
4591 delta);
4593 }
4594 else
4597 }
4599 /* If EXPR is an INTEGER_CST and ORIG is an arithmetic constant, return
4600 a version of EXPR that has TREE_OVERFLOW and/or TREE_CONSTANT_OVERFLOW
4601 set iff they are set in ORIG. Otherwise, return EXPR unchanged. */
4603 static tree
4605 {
4612 {
4614 /* Ensure constant sharing. */
4618 else
4619 {
4620 /* Avoid clobbering a shared constant. */
4625 }
4626 }
4628 }
4630 /* Perform a static_cast from EXPR to TYPE. When C_CAST_P is true,
4631 this static_cast is being attempted as one of the possible casts
4632 allowed by a C-style cast. (In that case, accessibility of base
4633 classes is not considered, and it is OK to cast away
4634 constness.) Return the result of the cast. *VALID_P is set to
4635 indicate whether or not the cast was valid. */
4637 static tree
4640 {
4641 tree intype;
4642 tree result;
4643 tree orig;
4647 /* Assume the cast is valid. */
4652 /* Determine what to do when casting away constness. */
4654 {
4655 /* C-style casts are allowed to cast away constness. With
4656 WARN_CAST_QUAL, we still want to issue a warning. */
4659 }
4660 else
4661 {
4662 /* A static_cast may not cast away constness. */
4665 }
4667 /* [expr.static.cast]
4669 An lvalue of type "cv1 B", where B is a class type, can be cast
4670 to type "reference to cv2 D", where D is a class derived (clause
4671 _class.derived_) from B, if a valid standard conversion from
4672 "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the
4673 same cv-qualification as, or greater cv-qualification than, cv1,
4674 and B is not a virtual base class of D. */
4675 /* We check this case before checking the validity of "TYPE t =
4676 EXPR;" below because for this case:
4678 struct B {};
4679 struct D : public B { D(const B&); };
4680 extern B& b;
4681 void f() { static_cast<const D&>(b); }
4683 we want to avoid constructing a new D. The standard is not
4684 completely clear about this issue, but our interpretation is
4685 consistent with other compilers. */
4694 && (c_cast_p
4696 {
4697 tree base;
4699 /* There is a standard conversion from "D*" to "B*" even if "B"
4700 is ambiguous or inaccessible. If this is really a
4701 static_cast, then we check both for inaccessibility and
4702 ambiguity. However, if this is a static_cast being performed
4703 because the user wrote a C-style cast, then accessibility is
4704 not considered. */
4707 NULL);
4709 /* Convert from "B*" to "D*". This function will check that "B"
4710 is not a virtual base of "D". */
4713 /* Convert the pointer to a reference -- but then remember that
4714 there are no expressions with reference type in C++. */
4716 }
4720 /* [expr.static.cast]
4722 An expression e can be explicitly converted to a type T using a
4723 static_cast of the form static_cast<T>(e) if the declaration T
4724 t(e);" is well-formed, for some invented temporary variable
4725 t. */
4727 c_cast_p);
4729 {
4732 /* Ignore any integer overflow caused by the cast. */
4735 /* [expr.static.cast]
4737 If T is a reference type, the result is an lvalue; otherwise,
4738 the result is an rvalue. */
4742 }
4744 /* [expr.static.cast]
4746 Any expression can be explicitly converted to type cv void. */
4750 /* [expr.static.cast]
4752 The inverse of any standard conversion sequence (clause _conv_),
4753 other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer
4754 (_conv.array_), function-to-pointer (_conv.func_), and boolean
4755 (_conv.bool_) conversions, can be performed explicitly using
4756 static_cast subject to the restriction that the explicit
4757 conversion does not cast away constness (_expr.const.cast_), and
4758 the following additional rules for specific cases: */
4759 /* For reference, the conversions not excluded are: integral
4760 promotions, floating point promotion, integral conversions,
4761 floating point conversions, floating-integral conversions,
4762 pointer conversions, and pointer to member conversions. */
4763 /* DR 128
4765 A value of integral _or enumeration_ type can be explicitly
4766 converted to an enumeration type. */
4767 /* The effect of all that is that any conversion between any two
4768 types which are integral, floating, or enumeration types can be
4769 performed. */
4772 {
4775 /* Ignore any integer overflow caused by the cast. */
4778 }
4787 {
4788 tree base;
4794 NULL);
4796 }
4800 {
4801 tree c1;
4802 tree c2;
4803 tree t1;
4804 tree t2;
4810 {
4811 t1 = (build_ptrmem_type
4814 t2 = (build_ptrmem_type
4817 }
4818 else
4819 {
4822 }
4824 {
4827 desc);
4829 c_cast_p);
4830 }
4831 }
4833 /* [expr.static.cast]
4835 An rvalue of type "pointer to cv void" can be explicitly
4836 converted to a pointer to object type. A value of type pointer
4837 to object converted to "pointer to cv void" and back to the
4838 original pointer type will have its original value. */
4842 {
4846 }
4850 }
4852 /* Return an expression representing static_cast<TYPE>(EXPR). */
4854 tree
4856 {
4857 tree result;
4864 {
4866 /* We don't know if it will or will not have side effects. */
4869 }
4871 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4872 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4885 }
4887 /* EXPR is an expression with member function or pointer-to-member
4888 function type. TYPE is a pointer type. Converting EXPR to TYPE is
4889 not permitted by ISO C++, but we accept it in some modes. If we
4890 are not in one of those modes, issue a diagnostic. Return the
4891 converted expression. */
4893 tree
4895 {
4896 tree intype;
4897 tree decl;
4910 else
4911 {
4915 }
4918 }
4920 /* Return a representation for a reinterpret_cast from EXPR to TYPE.
4921 If C_CAST_P is true, this reinterpret cast is being done as part of
4922 a C-style cast. If VALID_P is non-NULL, *VALID_P is set to
4923 indicate whether or not reinterpret_cast was valid. */
4925 static tree
4928 {
4929 tree intype;
4931 /* Assume the cast is invalid. */
4940 /* [expr.reinterpret.cast]
4941 An lvalue expression of type T1 can be cast to the type
4942 "reference to T2" if an expression of type "pointer to T1" can be
4943 explicitly converted to the type "pointer to T2" using a
4944 reinterpret_cast. */
4946 {
4948 {
4953 }
4955 /* Warn about a reinterpret_cast from "A*" to "B&" if "A" and
4956 "B" are related class types; the reinterpret_cast does not
4957 adjust the pointer. */
4966 expr = build_reinterpret_cast_1
4968 valid_p);
4972 }
4974 /* As a G++ extension, we consider conversions from member
4975 functions, and pointers to member functions to
4976 pointer-to-function and pointer-to-void types. If
4977 -Wno-pmf-conversions has not been specified,
4978 convert_member_func_to_ptr will issue an error message. */
4986 /* If the cast is not to a reference type, the lvalue-to-rvalue,
4987 array-to-pointer, and function-to-pointer conversions are
4988 performed. */
4991 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4992 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5002 /* [expr.reinterpret.cast]
5003 A pointer can be converted to any integral type large enough to
5004 hold it. */
5006 {
5010 }
5011 /* [expr.reinterpret.cast]
5012 A value of integral or enumeration type can be explicitly
5013 converted to a pointer. */
5015 /* OK */
5016 ;
5022 {
5028 /* Warn about possible alignment problems. */
5039 /* We need to strip nops here, because the frontend likes to
5040 create (int *)&a for array-to-pointer decay, instead of &a[0]. */
5045 }
5048 {
5050 /* Only issue a warning, as we have always supported this
5051 where possible, and it is necessary in some cases. DR 195
5052 addresses this issue, but as of 2004/10/26 is still in
5053 drafting. */
5056 }
5061 else
5062 {
5067 }
5070 }
5072 tree
5074 {
5079 {
5084 /* There might turn out to be side effects inside expr. */
5087 }
5091 }
5093 /* Perform a const_cast from EXPR to TYPE. If the cast is valid,
5094 return an appropriate expression. Otherwise, return
5095 error_mark_node. If the cast is not valid, and COMPLAIN is true,
5096 then a diagnostic will be issued. If VALID_P is non-NULL, we are
5097 performing a C-style cast, its value upon return will indicate
5098 whether or not the conversion succeeded. */
5100 static tree
5103 {
5104 tree src_type;
5105 tree reference_type;
5107 /* Callers are responsible for handling error_mark_node as a
5108 destination type. */
5110 /* In a template, callers should be building syntactic
5111 representations of casts, not using this machinery. */
5114 /* Assume the conversion is invalid. */
5119 {
5122 "which is not a pointer, "
5125 }
5128 {
5133 }
5136 /* Expressions do not really have reference types. */
5140 /* [expr.const.cast]
5142 An lvalue of type T1 can be explicitly converted to an lvalue of
5143 type T2 using the cast const_cast<T2&> (where T1 and T2 are object
5144 types) if a pointer to T1 can be explicitly converted to the type
5145 pointer to T2 using a const_cast. */
5147 {
5150 {
5155 }
5158 }
5159 else
5160 {
5162 /* If the destination type is not a reference type, the
5163 lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5164 conversions are performed. */
5168 }
5172 {
5174 {
5176 /* This cast is actually a C-style cast. Issue a warning if
5177 the user is making a potentially unsafe cast. */
5180 warning0,
5182 }
5184 {
5188 }
5189 else
5190 {
5192 /* build_c_cast puts on a NOP_EXPR to make the result not an
5193 lvalue. Strip such NOP_EXPRs if VALUE is being used in
5194 non-lvalue context. */
5199 }
5200 }
5206 }
5208 tree
5210 {
5215 {
5220 /* There might turn out to be side effects inside expr. */
5223 }
5227 }
5229 /* Build an expression representing an explicit C-style cast to type
5230 TYPE of expression EXPR. */
5232 tree
5234 {
5236 tree result;
5243 {
5246 /* We don't know if it will or will not have side effects. */
5249 }
5251 /* Casts to a (pointer to a) specific ObjC class (or 'id' or
5252 'Class') should always be retained, because this information aids
5253 in method lookup. */
5258 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5259 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5266 {
5267 /* Allow casting from T1* to T2[] because Cfront allows it.
5268 NIHCL uses it. It is not valid ISO C++ however. */
5270 {
5273 }
5274 else
5275 {
5278 }
5279 }
5283 {
5286 }
5288 /* A C-style cast can be a const_cast. */
5294 /* Or a static cast. */
5297 /* Or a reinterpret_cast. */
5301 /* The static_cast or reinterpret_cast may be followed by a
5302 const_cast. */
5304 /* A valid cast may result in errors if, for example, a
5305 conversion to am ambiguous base class is required. */
5307 {
5308 tree result_type;
5310 /* Non-class rvalues always have cv-unqualified type. */
5316 /* If the type of RESULT does not match TYPE, perform a
5317 const_cast to make it match. If the static_cast or
5318 reinterpret_cast succeeded, we will differ by at most
5319 cv-qualification, so the follow-on const_cast is guaranteed
5320 to succeed. */
5322 {
5325 }
5327 }
5330 }
5331 \f
5332 /* Build an assignment expression of lvalue LHS from value RHS.
5333 MODIFYCODE is the code for a binary operator that we use
5334 to combine the old value of LHS with RHS to get the new value.
5335 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
5337 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */
5339 tree
5341 {
5342 tree result;
5349 /* Avoid duplicate error messages from operands that had errors. */
5353 /* Handle control structure constructs used as "lvalues". */
5355 {
5356 /* Handle --foo = 5; as these are valid constructs in C++. */
5364 lhs,
5368 /* Handle (a, b) used as an "lvalue". */
5389 /* MIN_EXPR and MAX_EXPR are currently only permitted as lvalues,
5390 when neither operand has side-effects. */
5399 boolean_type_node,
5404 /* Fall through. */
5406 /* Handle (a ? b : c) used as an "lvalue". */
5408 {
5409 /* Produce (a ? (b = rhs) : (c = rhs))
5410 except that the RHS goes through a save-expr
5411 so the code to compute it is only emitted once. */
5412 tree cond;
5417 /* Check this here to avoid odd errors when trying to convert
5418 a throw to the type of the COND_EXPR. */
5422 cond = build_conditional_expr
5433 /* Make sure the code to compute the rhs comes out
5434 before the split. */
5438 }
5442 }
5445 {
5447 {
5449 /* Call convert to generate an error; see PR 11063. */
5454 }
5457 else
5458 {
5465 }
5466 }
5467 else
5468 {
5474 {
5475 /* `operator=' is not an inheritable operator. */
5478 else
5479 {
5486 }
5488 }
5489 else
5490 {
5491 /* A binary op has been requested. Combine the old LHS
5492 value with the RHS producing the value we should actually
5493 store into the LHS. */
5499 {
5503 }
5505 /* Now it looks like a plain assignment. */
5507 }
5510 }
5512 /* The left-hand side must be an lvalue. */
5516 /* Warn about modifying something that is `const'. Don't warn if
5517 this is initialization. */
5520 /* Functions are not modifiable, even though they are
5521 lvalues. */
5524 /* If it's an aggregate and any field is const, then it is
5525 effectively const. */
5530 /* If storing into a structure or union member, it has probably been
5531 given type `int'. Compute the type that would go with the actual
5532 amount of storage the member occupies. */
5538 {
5541 /* If storing in a field that is in actuality a short or narrower
5542 than one, we must store in the field in its actual type. */
5545 {
5546 /* Avoid warnings converting integral types back into enums for
5547 enum bit fields. */
5550 {
5554 }
5557 }
5558 }
5560 /* Convert new value to destination type. */
5563 {
5568 {
5572 }
5574 /* Allow array assignment in compiler-generated code. */
5582 from_array);
5583 }
5588 else
5589 {
5590 /* Avoid warnings on enum bit fields. */
5593 {
5597 }
5598 else
5605 /* Can't initialize directly from a TARGET_EXPR, since that would
5606 cause the lhs to be constructed twice, and possibly result in
5607 accidental self-initialization. So we force the TARGET_EXPR to be
5608 expanded without a target. */
5612 }
5618 {
5623 }
5632 /* If we got the LHS in a different type for storing in,
5633 convert the result back to the nominal type of LHS
5634 so that the value we return always has the same type
5635 as the LHS argument. */
5640 {
5644 }
5647 }
5649 tree
5651 {
5657 {
5662 {
5665 }
5666 }
5668 }
5670 \f
5671 /* Get difference in deltas for different pointer to member function
5672 types. Returns an integer constant of type PTRDIFF_TYPE_NODE. If
5673 the conversion is invalid, the constant is zero. If
5674 ALLOW_INVERSE_P is true, then allow reverse conversions as well.
5675 If C_CAST_P is true this conversion is taking place as part of a
5676 C-style cast.
5678 Note that the naming of FROM and TO is kind of backwards; the return
5679 value is what we add to a TO in order to get a FROM. They are named
5680 this way because we call this function to find out how to convert from
5681 a pointer to member of FROM to a pointer to member of TO. */
5683 static tree
5687 {
5688 tree binfo;
5689 base_kind kind;
5690 tree result;
5692 /* Assume no conversion is required. */
5698 {
5701 else
5702 {
5705 /* This is a reinterpret cast, we choose to do nothing. */
5709 else
5712 }
5713 }
5717 {
5720 }
5721 else
5722 {
5725 {
5728 else
5729 {
5730 /* This is a reinterpret cast, we choose to do nothing. */
5735 }
5736 }
5737 }
5740 result));
5741 }
5743 /* Return a constructor for the pointer-to-member-function TYPE using
5744 the other components as specified. */
5746 tree
5748 {
5750 tree delta_field;
5751 tree pfn_field;
5754 /* Pull the FIELD_DECLs out of the type. */
5758 /* Make sure DELTA has the type we want. */
5761 /* Finish creating the initializer. */
5774 }
5776 /* Build a constructor for a pointer to member function. It can be
5777 used to initialize global variables, local variable, or used
5778 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we
5779 want to be.
5781 If FORCE is nonzero, then force this conversion, even if
5782 we would rather not do it. Usually set when using an explicit
5783 cast. A C-style cast is being processed iff C_CAST_P is true.
5785 Return error_mark_node, if something goes wrong. */
5787 tree
5789 {
5790 tree fn;
5791 tree pfn_type;
5792 tree to_type;
5800 /* Handle multiple conversions of pointer to member functions. */
5802 {
5805 tree n;
5814 force,
5815 c_cast_p);
5817 /* We don't have to do any conversion to convert a
5818 pointer-to-member to its own type. But, we don't want to
5819 just return a PTRMEM_CST if there's an explicit cast; that
5820 cast should make the expression an invalid template argument. */
5822 {
5827 }
5832 /* Obtain the function pointer and the current DELTA. */
5835 else
5836 {
5839 }
5841 /* Just adjust the DELTA field. */
5848 }
5850 /* Handle null pointer to member function conversions. */
5852 {
5855 integer_zero_node,
5856 pfn);
5857 }
5864 /* In a template, we will have preserved the
5865 OFFSET_REF. */
5868 }
5870 /* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST
5871 given by CST.
5873 ??? There is no consistency as to the types returned for the above
5874 values. Some code acts as if it were a sizetype and some as if it were
5875 integer_type_node. */
5877 void
5879 {
5886 /* The class that the function belongs to. */
5889 /* The class that we're creating a pointer to member of. */
5892 /* First, calculate the adjustment to the function's class. */
5898 else
5899 {
5900 /* If we're dealing with a virtual function, we have to adjust 'this'
5901 again, to point to the base which provides the vtable entry for
5902 fn; the call will do the opposite adjustment. */
5909 /* We set PFN to the vtable offset at which the function can be
5910 found, plus one (unless ptrmemfunc_vbit_in_delta, in which
5911 case delta is shifted left, and then incremented). */
5918 {
5921 integer_one_node);
5936 }
5940 }
5941 }
5943 /* Return an expression for PFN from the pointer-to-member function
5944 given by T. */
5946 tree
5948 {
5950 {
5951 tree delta;
5952 tree pfn;
5957 }
5960 }
5962 /* Convert value RHS to type TYPE as preparation for an assignment to
5963 an lvalue of type TYPE. ERRTYPE is a string to use in error
5964 messages: "assignment", "return", etc. If FNDECL is non-NULL, we
5965 are doing the conversion in order to pass the PARMNUMth argument of
5966 FNDECL. */
5968 static tree
5971 {
5972 tree rhstype;
5975 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
5991 /* The RHS of an assignment cannot have void type. */
5993 {
5996 }
5998 /* Simplify the RHS if possible. */
6003 {
6011 else
6012 {
6018 {
6021 }
6022 }
6026 }
6028 /* [expr.ass]
6030 The expression is implicitly converted (clause _conv_) to the
6031 cv-unqualified type of the left operand.
6033 We allow bad conversions here because by the time we get to this point
6034 we are committed to doing the conversion. If we end up doing a bad
6035 conversion, convert_like will complain. */
6037 {
6038 /* When -Wno-pmf-conversions is use, we just silently allow
6039 conversions from pointers-to-members to plain pointers. If
6040 the conversion doesn't work, cp_convert will complain. */
6045 else
6046 {
6047 /* If the right-hand side has unknown type, then it is an
6048 overloaded function. Call instantiate_type to get error
6049 messages. */
6055 else
6058 }
6059 }
6061 {
6068 errtype);
6069 }
6072 }
6074 /* Convert RHS to be of type TYPE.
6075 If EXP is nonzero, it is the target of the initialization.
6076 ERRTYPE is a string to use in error messages.
6078 Two major differences between the behavior of
6079 `convert_for_assignment' and `convert_for_initialization'
6080 are that references are bashed in the former, while
6081 copied in the latter, and aggregates are assigned in
6082 the former (operator=) while initialized in the
6083 latter (X(X&)).
6085 If using constructor make sure no conversion operator exists, if one does
6086 exist, an ambiguity exists.
6088 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */
6090 tree
6093 {
6095 tree rhstype;
6098 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
6099 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */
6125 /* We accept references to incomplete types, so we can
6126 return here before checking if RHS is of complete type. */
6129 {
6130 /* This should eventually happen in convert_arguments. */
6138 {
6143 }
6145 }
6160 }
6161 \f
6162 /* If RETVAL is the address of, or a reference to, a local variable or
6163 temporary give an appropriate warning. */
6165 static void
6167 {
6172 {
6179 else
6181 }
6188 {
6191 {
6194 }
6198 {
6201 }
6202 }
6209 {
6212 whats_returned);
6213 else
6215 whats_returned);
6217 }
6218 }
6220 /* Check that returning RETVAL from the current function is valid.
6221 Return an expression explicitly showing all conversions required to
6222 change RETVAL into the function return type, and to assign it to
6223 the DECL_RESULT for the function. Set *NO_WARNING to true if
6224 code reaches end of non-void function warning shouldn't be issued
6225 on this RETURN_EXPR. */
6227 tree
6229 {
6230 tree result;
6231 /* The type actually returned by the function, after any
6232 promotions. */
6233 tree valtype;
6238 /* A `volatile' function is one that isn't supposed to return, ever.
6239 (This is a G++ extension, used to get better code for functions
6240 that call the `volatile' function.) */
6244 /* Check for various simple errors. */
6246 {
6250 }
6252 {
6254 /* If a return statement appears in a handler of the
6255 function-try-block of a constructor, the program is ill-formed. */
6258 /* You can't return a value from a constructor. */
6261 }
6264 {
6267 }
6269 /* When no explicit return-value is given in a function with a named
6270 return value, the named return value is used. */
6278 /* Check for a return statement with no return value in a function
6279 that's supposed to return a value. */
6281 {
6283 valtype);
6284 /* Clear this, so finish_function won't say that we reach the
6285 end of a non-void function (which we don't, we gave a
6286 return!). */
6288 /* And signal caller that TREE_NO_WARNING should be set on the
6289 RETURN_EXPR to avoid control reaches end of non-void function
6290 warnings in tree-cfg.c. */
6292 }
6293 /* Check for a return statement with a value in a function that
6294 isn't supposed to return a value. */
6296 {
6298 /* You can return a `void' value from a function of `void'
6299 type. In that case, we have to evaluate the expression for
6300 its side-effects. */
6302 else
6308 /* There's really no value to return, after all. */
6310 }
6312 /* Remember that this function can sometimes return without a
6313 value. */
6315 else
6316 /* Remember that this function did return a value. */
6319 /* Check for erroneous operands -- but after giving ourselves a
6320 chance to provide an error about returning a value from a void
6321 function. */
6323 {
6326 }
6328 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */
6332 && ! flag_check_new
6337 /* Effective C++ rule 15. See also start_function. */
6340 {
6343 /* The function return type must be a reference to the current
6344 class. */
6346 && same_type_ignoring_top_level_qualifiers_p
6348 {
6349 /* Returning '*this' is obviously OK. */
6352 /* If we are calling a function whose return type is the same of
6353 the current class reference, it is ok. */
6357 }
6361 }
6363 /* The fabled Named Return Value optimization, as per [class.copy]/15:
6365 [...] For a function with a class return type, if the expression
6366 in the return statement is the name of a local object, and the cv-
6367 unqualified type of the local object is the same as the function
6368 return type, an implementation is permitted to omit creating the tem-
6369 porary object to hold the function return value [...]
6371 So, if this is a value-returning function that always returns the same
6372 local variable, remember it.
6374 It might be nice to be more flexible, and choose the first suitable
6375 variable even if the function sometimes returns something else, but
6376 then we run the risk of clobbering the variable we chose if the other
6377 returned expression uses the chosen variable somehow. And people expect
6378 this restriction, anyway. (jason 2000-11-19)
6380 See finish_function and finalize_nrv for the rest of this optimization. */
6383 {
6394 (TYPE_MAIN_VARIANT
6397 else
6399 }
6401 /* We don't need to do any conversions when there's nothing being
6402 returned. */
6406 /* Do any required conversions. */
6408 /* No conversions are required. */
6409 ;
6410 else
6411 {
6412 /* The type the function is declared to return. */
6415 /* The functype's return type will have been set to void, if it
6416 was an incomplete type. Just treat this as 'return;' */
6420 /* First convert the value to the function's return type, then
6421 to the type of return value's location to handle the
6422 case that functype is smaller than the valtype. */
6423 retval = convert_for_initialization
6428 /* If the conversion failed, treat this just like `return;'. */
6431 /* We can't initialize a register from a AGGR_INIT_EXPR. */
6437 else
6439 }
6441 /* Actually copy the value returned into the appropriate location. */
6446 }
6448 \f
6449 /* Returns nonzero if the pointer-type FROM can be converted to the
6450 pointer-type TO via a qualification conversion. If CONSTP is -1,
6451 then we return nonzero if the pointers are similar, and the
6452 cv-qualification signature of FROM is a proper subset of that of TO.
6454 If CONSTP is positive, then all outer pointers have been
6455 const-qualified. */
6457 static int
6459 {
6463 {
6472 /* Const and volatile mean something different for function types,
6473 so the usual checks are not appropriate. */
6475 {
6476 /* In Objective-C++, some types may have been 'volatilized' by
6477 the compiler for EH; when comparing them here, the volatile
6478 qualification must be ignored. */
6485 {
6489 }
6493 }
6498 }
6499 }
6501 /* When comparing, say, char ** to char const **, this function takes
6502 the 'char *' and 'char const *'. Do not pass non-pointer/reference
6503 types to this function. */
6505 int
6507 {
6509 }
6511 /* Returns 1 if to and from are (possibly multi-level) pointers to the same
6512 type or inheritance-related types, regardless of cv-quals. */
6514 int
6516 {
6518 {
6519 /* Any target type is similar enough to void. */
6545 return comptypes
6548 }
6549 }
6551 /* Return true if TO and FROM (both of which are POINTER_TYPEs or
6552 pointer-to-member types) are the same, ignoring cv-qualification at
6553 all levels. */
6555 bool
6557 {
6559 {
6570 }
6571 }
6573 /* Returns the type qualifiers for this type, including the qualifiers on the
6574 elements for an array type. */
6576 int
6578 {
6583 }
6585 /* Returns nonzero if the TYPE contains a mutable member. */
6587 bool
6589 {
6593 }
6595 /* Apply the TYPE_QUALS to the new DECL. */
6596 void
6598 {
6606 {
6607 /* This was an error in C++98 (cv-qualifiers cannot be added to
6608 a function type), but DR 295 makes the code well-formed by
6609 dropping the extra qualifiers. */
6611 {
6615 }
6619 }
6621 /* Avoid setting TREE_READONLY incorrectly. */
6623 the object. */
6625 /* If the type isn't complete, we don't know yet if it will need
6626 constructing. */
6628 /* If the type has a mutable component, that component might be
6629 modified. */
6634 }
6636 /* Subroutine of casts_away_constness. Make T1 and T2 point at
6637 exemplar types such that casting T1 to T2 is casting away constness
6638 if and only if there is no implicit conversion from T1 to T2. */
6640 static void
6642 {
6646 /* [expr.const.cast]
6648 For multi-level pointer to members and multi-level mixed pointers
6649 and pointers to members (conv.qual), the "member" aspect of a
6650 pointer to member level is ignored when determining if a const
6651 cv-qualifier has been cast away. */
6652 /* [expr.const.cast]
6654 For two pointer types:
6656 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type
6657 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type
6658 K is min(N,M)
6660 casting from X1 to X2 casts away constness if, for a non-pointer
6661 type T there does not exist an implicit conversion (clause
6662 _conv_) from:
6664 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N *
6666 to
6668 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */
6671 {
6677 }
6684 else
6688 else
6696 }
6698 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
6699 constness. */
6701 static bool
6703 {
6705 {
6706 /* [expr.const.cast]
6708 Casting from an lvalue of type T1 to an lvalue of type T2
6709 using a reference cast casts away constness if a cast from an
6710 rvalue of type "pointer to T1" to the type "pointer to T2"
6711 casts away constness. */
6715 }
6718 /* [expr.const.cast]
6720 Casting from an rvalue of type "pointer to data member of X
6721 of type T1" to the type "pointer to data member of Y of type
6722 T2" casts away constness if a cast from an rvalue of type
6723 "pointer to T1" to the type "pointer to T2" casts away
6724 constness. */
6725 return casts_away_constness
6729 /* Casting away constness is only something that makes sense for
6730 pointer or reference types. */
6735 /* Top-level qualifiers don't matter. */
6743 }
6745 /* If T is a REFERENCE_TYPE return the type to which T refers.
6746 Otherwise, return T itself. */
6748 tree
6750 {
6754 }
6757 /* Return nonzero if REF is an lvalue valid for this language;
6758 otherwise, print an error message and return zero. USE says
6759 how the lvalue is being used and so selects the error message. */
6761 int
6763 {
6770 }