| blob | f68b48477151de63c06136419933a19f06dfb440 |
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. */
62 /* Do `exp = require_complete_type (exp);' to make sure exp
63 does not have an incomplete type. (That includes void types.)
64 Returns the error_mark_node if the VALUE does not have
65 complete type when this function returns. */
67 tree
69 {
70 tree type;
77 else
83 /* First, detect a valid value with a complete type. */
89 else
91 }
93 /* Try to complete TYPE, if it is incomplete. For example, if TYPE is
94 a template instantiation, do the instantiation. Returns TYPE,
95 whether or not it could be completed, unless something goes
96 horribly wrong, in which case the error_mark_node is returned. */
98 tree
100 {
102 /* Rather than crash, we return something sure to cause an error
103 at some point. */
107 ;
109 {
114 needs_constructing
116 has_nontrivial_dtor
119 {
122 }
123 }
128 }
130 /* Like complete_type, but issue an error if the TYPE cannot be completed.
131 VALUE is used for informative diagnostics.
132 Returns NULL_TREE if the type cannot be made complete. */
134 tree
136 {
139 /* We already issued an error. */
142 {
145 }
146 else
148 }
150 /* Return truthvalue of whether type of EXP is instantiated. */
152 int
154 {
157 }
159 \f
160 /* Return the common type of two parameter lists.
161 We assume that comptypes has already been done and returned 1;
162 if that isn't so, this may crash.
164 As an optimization, free the space we allocate if the parameter
165 lists are already common. */
167 static tree
169 {
179 else
180 {
183 }
192 {
194 {
197 }
199 {
201 {
204 }
205 }
206 else
207 {
211 }
213 {
216 }
217 else
219 }
224 }
226 /* Given a type, perhaps copied for a typedef,
227 find the "original" version of it. */
228 static tree
230 {
232 {
240 }
242 }
244 /* T1 and T2 are arithmetic or enumeration types. Return the type
245 that will result from the "usual arithmetic conversions" on T1 and
246 T2 as described in [expr]. */
248 tree
250 {
253 tree attributes;
255 /* FIXME: Attributes. */
265 /* In what follows, we slightly generalize the rules given in [expr] so
266 as to deal with `long long' and `complex'. First, merge the
267 attributes. */
270 /* If one type is complex, form the common type of the non-complex
271 components, then make that complex. Use T1 or T2 if it is the
272 required type. */
274 {
277 tree subtype
284 else
286 attributes);
287 }
290 {
291 /* When we get here we should have two vectors of the same size.
292 Just prefer the unsigned one if present. */
295 else
297 }
299 /* If only one is real, use it as the result. */
305 /* Perform the integral promotions. */
307 {
310 }
312 /* Both real or both integers; use the one with greater precision. */
318 /* The types are the same; no need to do anything fancy. */
323 {
324 /* If one is a sizetype, use it so size_binop doesn't blow up. */
330 /* If one is unsigned long long, then convert the other to unsigned
331 long long. */
335 attributes);
336 /* If one is a long long, and the other is an unsigned long, and
337 long long can represent all the values of an unsigned long, then
338 convert to a long long. Otherwise, convert to an unsigned long
339 long. Otherwise, if either operand is long long, convert the
340 other to long long.
342 Since we're here, we know the TYPE_PRECISION is the same;
343 therefore converting to long long cannot represent all the values
344 of an unsigned long, so we choose unsigned long long in that
345 case. */
348 {
350 ? long_long_unsigned_type_node
353 }
355 /* Go through the same procedure, but for longs. */
359 attributes);
362 {
366 }
367 /* Otherwise prefer the unsigned one. */
370 else
372 }
373 else
374 {
378 attributes);
382 attributes);
386 attributes);
388 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of
389 the standard C++ floating-point types. Logic earlier in this
390 function has already eliminated the possibility that
391 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no
392 compelling reason to choose one or the other. */
394 }
395 }
397 /* Subroutine of composite_pointer_type to implement the recursive
398 case. See that function for documentation fo the parameters. */
400 static tree
402 {
403 tree pointee1;
404 tree pointee2;
405 tree result_type;
406 tree attributes;
408 /* Determine the types pointed to by T1 and T2. */
410 {
413 }
414 else
415 {
418 }
420 /* [expr.rel]
422 Otherwise, the composite pointer type is a pointer type
423 similar (_conv.qual_) to the type of one of the operands,
424 with a cv-qualification signature (_conv.qual_) that is the
425 union of the cv-qualification signatures of the operand
426 types. */
434 else
435 {
440 }
444 /* If the original types were pointers to members, so is the
445 result. */
447 {
454 result_type);
455 }
456 else
459 /* Merge the attributes. */
462 }
464 /* Return the composite pointer type (see [expr.rel]) for T1 and T2.
465 ARG1 and ARG2 are the values with those types. The LOCATION is a
466 string describing the current location, in case an error occurs.
468 This routine also implements the computation of a common type for
469 pointers-to-members as per [expr.eq]. */
471 tree
474 {
475 tree class1;
476 tree class2;
478 /* [expr.rel]
480 If one operand is a null pointer constant, the composite pointer
481 type is the type of the other operand. */
487 /* We have:
489 [expr.rel]
491 If one of the operands has type "pointer to cv1 void*", then
492 the other has type "pointer to cv2T", and the composite pointer
493 type is "pointer to cv12 void", where cv12 is the union of cv1
494 and cv2.
496 If either type is a pointer to void, make sure it is T1. */
498 {
499 tree t;
503 }
505 /* Now, if T1 is a pointer to void, merge the qualifiers. */
507 {
508 tree attributes;
509 tree result_type;
514 result_type
519 /* Merge the attributes. */
522 }
526 {
529 }
531 /* [expr.eq] permits the application of a pointer conversion to
532 bring the pointers to a common type. */
538 {
543 t2 = (build_pointer_type
546 t1 = (build_pointer_type
548 else
549 {
553 }
554 }
555 /* [expr.eq] permits the application of a pointer-to-member
556 conversion to change the class type of one of the types. */
560 {
568 else
569 {
573 }
574 }
577 }
579 /* Return the merged type of two types.
580 We assume that comptypes has already been done and returned 1;
581 if that isn't so, this may crash.
583 This just combines attributes and default arguments; any other
584 differences would cause the two types to compare unalike. */
586 tree
588 {
591 tree attributes;
593 /* Save time if the two types are the same. */
599 /* If one type is nonsense, use the other. */
605 /* Merge the attributes. */
617 {
620 /* For two pointers, do this recursively on the target type. */
621 {
627 else
636 }
639 {
641 tree pointee;
646 pointee);
649 }
652 {
654 /* Save space: see if the result is identical to one of the args. */
659 /* Merge the element types, and have a size if either arg has one. */
660 t1 = build_cplus_array_type
663 }
666 /* Function types: prefer the one that specified arg types.
667 If both do, merge the arg types. Also merge the return types. */
668 {
674 /* Save space: see if the result is identical to one of the args. */
680 /* Simple way if one arg fails to specify argument types. */
682 {
687 }
690 {
695 }
700 }
703 {
704 /* Get this value the long way, since TYPE_METHOD_BASETYPE
705 is just the main variant of this. */
708 tree t3;
710 /* If this was a member function type, get back to the
711 original type of type member function (i.e., without
712 the class instance variable up front. */
722 }
725 /* There is no need to merge attributes into a TYPENAME_TYPE.
726 When the type is instantiated it will have whatever
727 attributes result from the instantiation. */
731 }
733 }
735 /* Return the common type of two types.
736 We assume that comptypes has already been done and returned 1;
737 if that isn't so, this may crash.
739 This is the type for the result of most arithmetic operations
740 if the operands have the given two types. */
742 tree
744 {
748 /* If one type is nonsense, bail. */
766 else
768 }
769 \f
770 /* Compare two exception specifier types for exactness or subsetness, if
771 allowed. Returns false for mismatch, true for match (same, or
772 derived and !exact).
774 [except.spec] "If a class X ... objects of class X or any class publicly
775 and unambiguously derived from X. Similarly, if a pointer type Y * ...
776 exceptions of type Y * or that are pointers to any type publicly and
777 unambiguously derived from Y. Otherwise a function only allows exceptions
778 that have the same type ..."
779 This does not mention cv qualifiers and is different to what throw
780 [except.throw] and catch [except.catch] will do. They will ignore the
781 top level cv qualifiers, and allow qualifiers in the pointer to class
782 example.
784 We implement the letter of the standard. */
786 static bool
788 {
792 {
798 {
803 }
811 }
813 }
815 /* Return true if TYPE1 and TYPE2 are equivalent exception specifiers.
816 If EXACT is false, T2 can be stricter than T1 (according to 15.4/7),
817 otherwise it must be exact. Exception lists are unordered, but
818 we've already filtered out duplicates. Most lists will be in order,
819 we should try to make use of that. */
821 bool
823 {
824 tree probe;
825 tree base;
840 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1.
841 Count how many we find, to determine exactness. For exact matching and
842 ordered T1, T2, this is an O(n) operation, otherwise its worst case is
843 O(nm). */
845 {
847 {
852 {
855 length++;
857 }
858 }
861 }
863 }
865 /* Compare the array types T1 and T2. ALLOW_REDECLARATION is true if
866 [] can match [size]. */
868 static bool
870 {
871 tree d1;
872 tree d2;
878 /* The type of the array elements must be the same. */
888 /* If one of the arrays is dimensionless, and the other has a
889 dimension, they are of different types. However, it is valid to
890 write:
892 extern int a[];
893 int a[3];
895 by [basic.link]:
897 declarations for an array object can specify
898 array types that differ by the presence or absence of a major
899 array bound (_dcl.array_). */
903 /* Check that the dimensions are the same. */
912 {
913 /* With abi-1 we do not fold non-dependent array bounds, (and
914 consequently mangle them incorrectly). We must therefore
915 fold them here, to verify the domains have the same
916 value. */
919 }
925 }
927 /* Return true if T1 and T2 are related as allowed by STRICT. STRICT
928 is a bitwise-or of the COMPARE_* flags. */
930 bool
932 {
936 /* Suppress errors caused by previously reported errors. */
942 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the
943 current instantiation. */
945 {
950 }
953 {
958 }
960 /* If either type is the internal version of sizetype, use the
961 language version. */
975 /* Different classes of types can't be compatible. */
979 /* Qualifiers must match. For array types, we will check when we
980 recur on the array element types. */
987 /* Allow for two different type nodes which have essentially the same
988 definition. Note that we already checked for equality of the type
989 qualifiers (just above). */
995 /* Compare the types. Break out if they could be the same. */
997 {
1009 /* Don't check inheritance. */
1011 /* Fall through. */
1053 /* Target types must match incl. qualifiers. */
1092 }
1094 /* If we get here, we know that from a target independent POV the
1095 types are the same. Make sure the target attributes are also
1096 the same. */
1098 }
1100 /* Returns 1 if TYPE1 is at least as qualified as TYPE2. */
1102 bool
1104 {
1108 /* All qualifiers for TYPE2 must also appear in TYPE1. */
1110 }
1112 /* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is
1113 more cv-qualified that TYPE1, and 0 otherwise. */
1115 int
1117 {
1130 }
1132 /* Returns 1 if the cv-qualification signature of TYPE1 is a proper
1133 subset of the cv-qualification signature of TYPE2, and the types
1134 are similar. Returns -1 if the other way 'round, and 0 otherwise. */
1136 int
1138 {
1143 else
1145 }
1147 /* If two types share a common base type, return that basetype.
1148 If there is not a unique most-derived base type, this function
1149 returns ERROR_MARK_NODE. */
1151 static tree
1153 {
1157 /* If one is a baseclass of another, that's good enough. */
1163 /* Otherwise, try to find a unique baseclass of TT1
1164 that is shared by TT2, and follow that down. */
1166 {
1171 {
1178 }
1179 }
1181 /* Same for TT2. */
1183 {
1188 {
1195 }
1196 }
1198 }
1199 \f
1200 /* Subroutines of `comptypes'. */
1202 /* Return true if two parameter type lists PARMS1 and PARMS2 are
1203 equivalent in the sense that functions with those parameter types
1204 can have equivalent types. The two lists must be equivalent,
1205 element by element. */
1207 bool
1209 {
1212 /* An unspecified parmlist matches any specified parmlist
1213 whose argument types don't need default promotions. */
1218 {
1219 /* If one parmlist is shorter than the other,
1220 they fail to match. */
1225 }
1227 }
1229 \f
1230 /* Process a sizeof or alignof expression where the operand is a
1231 type. */
1233 tree
1235 {
1237 tree value;
1245 {
1249 }
1257 {
1261 }
1262 else
1265 complain);
1268 }
1270 /* Process a sizeof expression where the operand is an expression. */
1272 static tree
1274 {
1279 {
1285 }
1290 {
1293 }
1295 {
1299 }
1301 {
1304 }
1305 else
1309 }
1311 /* Implement the __alignof keyword: Return the minimum required
1312 alignment of E, measured in bytes. For VAR_DECL's and
1313 FIELD_DECL's return DECL_ALIGN (which can be set from an
1314 "aligned" __attribute__ specification). */
1316 static tree
1318 {
1319 tree t;
1325 {
1331 }
1338 {
1341 }
1346 {
1350 }
1352 {
1355 }
1356 else
1360 }
1362 /* Process a sizeof or alignof expression E with code OP where the operand
1363 is an expression. */
1365 tree
1367 {
1370 else
1372 }
1373 \f
1374 /* EXPR is being used in a context that is not a function call.
1375 Enforce:
1377 [expr.ref]
1379 The expression can be used only as the left-hand operand of a
1380 member function call.
1382 [expr.mptr.operator]
1384 If the result of .* or ->* is a function, then that result can be
1385 used only as the operand for the function call operator ().
1387 by issuing an error message if appropriate. Returns true iff EXPR
1388 violates these rules. */
1390 bool
1392 {
1394 {
1397 }
1399 }
1401 /* Perform the conversions in [expr] that apply when an lvalue appears
1402 in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and
1403 function-to-pointer conversions.
1405 In addition manifest constants are replaced by their values. */
1407 tree
1409 {
1410 tree type;
1420 {
1423 }
1427 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
1428 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */
1431 {
1434 }
1440 {
1441 tree adr;
1442 tree ptrtype;
1449 {
1453 }
1457 {
1460 }
1465 {
1470 }
1471 /* This way is better for a COMPONENT_REF since it can
1472 simplify the offset for a component. */
1475 }
1477 /* [basic.lval]: Class rvalues can have cv-qualified types; non-class
1478 rvalues always have cv-unqualified types. */
1483 }
1485 tree
1487 {
1494 }
1496 /* EXPR is an expression with an integral or enumeration type.
1497 Perform the integral promotions in [conv.prom], and return the
1498 converted value. */
1500 tree
1502 {
1503 tree type;
1504 tree promoted_type;
1512 }
1514 /* Take the address of an inline function without setting TREE_ADDRESSABLE
1515 or TREE_USED. */
1517 tree
1519 {
1524 }
1526 /* Returns nonzero iff exp is a STRING_CST or the result of applying
1527 decay_conversion to one. */
1529 int
1531 {
1532 tree t;
1543 {
1544 /* Make sure that we don't try to convert between char and wchar_t. */
1547 }
1548 else
1549 {
1550 /* Is this a string constant which has decayed to 'const char *'? */
1558 }
1560 /* This warning is not very useful, as it complains about printf. */
1565 }
1567 /* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we
1568 can, for example, use as an lvalue. This code used to be in
1569 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c'
1570 expressions, where we're dealing with aggregates. But now it's again only
1571 called from unary_complex_lvalue. The case (in particular) that led to
1572 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd
1573 get it there. */
1575 static tree
1577 {
1578 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that
1579 the first operand is always the one to be used if both operands
1580 are equal, so we know what conditional expression this used to be. */
1582 {
1583 /* The following code is incorrect if either operand side-effects. */
1586 return
1594 }
1596 return
1600 }
1602 /* Given the TYPE of an anonymous union field inside T, return the
1603 FIELD_DECL for the field. If not found return NULL_TREE. Because
1604 anonymous unions can nest, we must also search all anonymous unions
1605 that are directly reachable. */
1607 tree
1609 {
1610 tree field;
1613 {
1619 /* If we find it directly, return the field. */
1622 {
1624 }
1626 /* Otherwise, it could be nested, search harder. */
1629 {
1633 }
1634 }
1636 }
1638 /* Build an expression representing OBJECT.MEMBER. OBJECT is an
1639 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is
1640 non-NULL, it indicates the path to the base used to name MEMBER.
1641 If PRESERVE_REFERENCE is true, the expression returned will have
1642 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression
1643 returned will have the type referred to by the reference.
1645 This function does not perform access control; that is either done
1646 earlier by the parser when the name of MEMBER is resolved to MEMBER
1647 itself, or later when overload resolution selects one of the
1648 functions indicated by MEMBER. */
1650 tree
1653 {
1654 tree object_type;
1655 tree member_scope;
1663 /* [expr.ref]
1665 The type of the first expression shall be "class object" (of a
1666 complete type). */
1672 {
1676 }
1678 /* The standard does not seem to actually say that MEMBER must be a
1679 member of OBJECT_TYPE. However, that is clearly what is
1680 intended. */
1682 {
1687 }
1688 else
1690 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will
1691 presently be the anonymous union. Go outwards until we find a
1692 type related to OBJECT_TYPE. */
1695 object_type))
1698 {
1701 else
1704 }
1706 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into
1707 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue
1708 in the frontend; only _DECLs and _REFs are lvalues in the backend. */
1709 {
1713 }
1715 /* In [expr.ref], there is an explicit list of the valid choices for
1716 MEMBER. We check for each of those cases here. */
1718 {
1719 /* A static data member. */
1721 /* If OBJECT has side-effects, they are supposed to occur. */
1724 }
1726 {
1727 /* A non-static data member. */
1730 tree member_type;
1735 /* Convert OBJECT to the type of MEMBER. */
1738 {
1739 tree binfo;
1740 base_kind kind;
1747 /* It is invalid to try to get to a virtual base of a
1748 NULL object. The most common cause is invalid use of
1749 offsetof macro. */
1751 {
1754 member);
1757 }
1759 /* Convert to the base. */
1762 /* If we found the base successfully then we should be able
1763 to convert to it successfully. */
1765 }
1767 /* Complain about other invalid uses of offsetof, even though they will
1768 give the right answer. Note that we complain whether or not they
1769 actually used the offsetof macro, since there's no way to know at this
1770 point. So we just give a warning, instead of a pedwarn. */
1771 /* Do not produce this warning for base class field references, because
1772 we know for a fact that didn't come from offsetof. This does occur
1773 in various testsuite cases where a null object is passed where a
1774 vtable access is required. */
1779 {
1781 member);
1783 }
1785 /* If MEMBER is from an anonymous aggregate, we have converted
1786 OBJECT so that it refers to the class containing the
1787 anonymous union. Generate a reference to the anonymous union
1788 itself, and recur to find MEMBER. */
1790 /* When this code is called from build_field_call, the
1791 object already has the type of the anonymous union.
1792 That is because the COMPONENT_REF was already
1793 constructed, and was then disassembled before calling
1794 build_field_call. After the function-call code is
1795 cleaned up, this waste can be eliminated. */
1796 && (!same_type_ignoring_top_level_qualifiers_p
1798 {
1799 tree anonymous_union;
1804 anonymous_union,
1806 preserve_reference);
1807 }
1809 /* Compute the type of the field, as described in [expr.ref]. */
1813 {
1817 /* A field is const (volatile) if the enclosing object, or the
1818 field itself, is const (volatile). But, a mutable field is
1819 not const, even within a const object. */
1823 }
1826 NULL_TREE);
1829 /* Mark the expression const or volatile, as appropriate. Even
1830 though we've dealt with the type above, we still have to mark the
1831 expression itself. */
1836 }
1838 {
1839 /* The member is a (possibly overloaded) member function. */
1840 tree functions;
1841 tree type;
1843 /* If the MEMBER is exactly one static member function, then we
1844 know the type of the expression. Otherwise, we must wait
1845 until overload resolution has been performed. */
1850 else
1852 /* Note that we do not convert OBJECT to the BASELINK_BINFO
1853 base. That will happen when the function is called. */
1855 }
1857 {
1858 /* The member is an enumerator. */
1860 /* If OBJECT has side-effects, they are supposed to occur. */
1864 }
1865 else
1866 {
1869 }
1872 /* [expr.ref]
1874 If E2 is declared to have type "reference to T", then ... the
1875 type of E1.E2 is T. */
1879 }
1881 /* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if
1882 SCOPE is NULL, by OBJECT.~DTOR_NAME. */
1884 static tree
1886 {
1889 tree expr;
1892 {
1896 }
1898 {
1902 }
1905 expr = (adjust_result_of_qualified_name_lookup
1908 }
1910 /* An expression of the form "A::template B" has been resolved to
1911 DECL. Issue a diagnostic if B is not a template or template
1912 specialization. */
1914 void
1916 {
1917 /* The standard says:
1919 [temp.names]
1921 If a name prefixed by the keyword template is not a member
1922 template, the program is ill-formed.
1924 DR 228 removed the restriction that the template be a member
1925 template.
1927 DR 96, if accepted would add the further restriction that explicit
1928 template arguments must be provided if the template keyword is
1929 used, but, as of 2005-10-16, that DR is still in "drafting". If
1930 this DR is accepted, then the semantic checks here can be
1931 simplified, as the entity named must in fact be a template
1932 specialization, rather than, as at present, a set of overloaded
1933 functions containing at least one template function. */
1936 {
1939 else
1940 {
1941 tree fns;
1946 {
1956 }
1959 }
1960 }
1961 }
1963 /* This function is called by the parser to process a class member
1964 access expression of the form OBJECT.NAME. NAME is a node used by
1965 the parser to represent a name; it is not yet a DECL. It may,
1966 however, be a BASELINK where the BASELINK_FUNCTIONS is a
1967 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and
1968 there is no reason to do the lookup twice, so the parser keeps the
1969 BASELINK. TEMPLATE_P is true iff NAME was explicitly declared to
1970 be a template via the use of the "A::template B" syntax. */
1972 tree
1974 {
1975 tree expr;
1976 tree object_type;
1977 tree member;
1985 /* If OBJECT is an ObjC class instance, we must obey ObjC access rules. */
1992 {
1995 /* If NAME is just an IDENTIFIER_NODE, then the expression
1996 is dependent. */
1998 /* If NAME is "f<args>", where either 'f' or 'args' is
1999 dependent, then the expression is dependent. */
2003 /* If NAME is "T::X" where "T" is dependent, then the
2004 expression is dependent. */
2010 }
2012 /* [expr.ref]
2014 The type of the first expression shall be "class object" (of a
2015 complete type). */
2020 {
2024 }
2027 /* A member function that has already been looked up. */
2029 else
2030 {
2033 tree scope;
2036 {
2045 }
2048 {
2049 /* A qualified name. The qualifying class or namespace `S' has
2050 already been looked up; it is either a TYPE or a
2051 NAMESPACE_DECL. The member name is either an IDENTIFIER_NODE
2052 or a BIT_NOT_EXPR. */
2060 /* If SCOPE is a namespace, then the qualified name does not
2061 name a member of OBJECT_TYPE. */
2063 {
2067 }
2069 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */
2074 {
2077 }
2078 }
2079 else
2080 {
2083 }
2087 else
2088 {
2089 /* Look up the member. */
2093 {
2096 }
2099 }
2102 {
2107 else
2108 {
2111 }
2112 }
2113 }
2124 {
2126 {
2130 }
2133 NULL_TREE);
2134 }
2137 }
2139 /* Return an expression for the MEMBER_NAME field in the internal
2140 representation of PTRMEM, a pointer-to-member function. (Each
2141 pointer-to-member function type gets its own RECORD_TYPE so it is
2142 more convenient to access the fields by name than by FIELD_DECL.)
2143 This routine converts the NAME to a FIELD_DECL and then creates the
2144 node for the complete expression. */
2146 tree
2148 {
2149 tree ptrmem_type;
2150 tree member;
2151 tree member_type;
2153 /* This code is a stripped down version of
2154 build_class_member_access_expr. It does not work to use that
2155 routine directly because it expects the object to be of class
2156 type. */
2165 }
2167 /* Given an expression PTR for a pointer, return an expression
2168 for the value pointed to.
2169 ERRORSTRING is the name of the operator to appear in error messages.
2171 This function may need to overload OPERATOR_FNNAME.
2172 Must also handle REFERENCE_TYPEs for C++. */
2174 tree
2176 {
2178 tree rval;
2181 {
2185 }
2194 else
2196 }
2198 tree
2200 {
2214 {
2215 /* [expr.unary.op]
2217 If the type of the expression is "pointer to T," the type
2218 of the result is "T."
2220 We must use the canonical variant because certain parts of
2221 the back end, like fold, do pointer comparisons between
2222 types. */
2226 {
2227 /* A pointer to incomplete type (other than cv void) can be
2228 dereferenced [expr.unary.op]/1 */
2231 }
2234 /* The POINTER was something like `&x'. We simplify `*&x' to
2235 `x'. */
2237 else
2238 {
2241 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2242 so that we get the proper error message if the result is used
2243 to assign to. Also, &* is supposed to be a no-op. */
2249 }
2250 }
2251 /* `pointer' won't be an error_mark_node if we were given a
2252 pointer to member, so it's cool to check for this here. */
2256 {
2259 else
2261 }
2263 }
2265 /* This handles expressions of the form "a[i]", which denotes
2266 an array reference.
2268 This is logically equivalent in C to *(a+i), but we may do it differently.
2269 If A is a variable or a member, we generate a primitive ARRAY_REF.
2270 This avoids forcing the array out of registers, and can work on
2271 arrays that are not lvalues (for example, members of structures returned
2272 by functions).
2274 If INDEX is of some user-defined type, it must be converted to
2275 integer type. Otherwise, to make a compatible PLUS_EXPR, it
2276 will inherit the type of the array, which will be some pointer type. */
2278 tree
2280 {
2282 {
2285 }
2291 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference
2292 inside it. */
2294 {
2296 {
2300 }
2303 return build_conditional_expr
2310 }
2313 {
2319 {
2322 }
2324 /* Apply integral promotions *after* noticing character types.
2325 (It is unclear why we do these promotions -- the standard
2326 does not say that we should. In fact, the natural thing would
2327 seem to be to convert IDX to ptrdiff_t; we're performing
2328 pointer arithmetic.) */
2331 /* An array that is indexed by a non-constant
2332 cannot be stored in a register; we must be able to do
2333 address arithmetic on its address.
2334 Likewise an array of elements of variable size. */
2339 {
2342 }
2344 /* An array that is indexed by a constant value which is not within
2345 the array bounds cannot be stored in a register either; because we
2346 would get a crash in store_bit_field/extract_bit_field when trying
2347 to access a non-existent part of the register. */
2351 {
2354 }
2359 /* Note in C++ it is valid to subscript a `register' array, since
2360 it is valid to take the address of something with that
2361 storage specification. */
2363 {
2369 }
2373 /* Array ref is const/volatile if the array elements are
2374 or if the array is.. */
2382 }
2384 {
2388 /* Put the integer in IND to simplify error checking. */
2390 {
2394 }
2400 {
2403 }
2405 {
2408 }
2412 }
2413 }
2414 \f
2415 /* Resolve a pointer to member function. INSTANCE is the object
2416 instance to use, if the member points to a virtual member.
2418 This used to avoid checking for virtual functions if basetype
2419 has no virtual functions, according to an earlier ANSI draft.
2420 With the final ISO C++ rules, such an optimization is
2421 incorrect: A pointer to a derived member can be static_cast
2422 to pointer-to-base-member, as long as the dynamic object
2423 later has the right member. */
2425 tree
2427 {
2432 {
2439 {
2441 {
2442 /* Extracting the function address from a pmf is only
2443 allowed with -Wno-pmf-conversions. It only works for
2444 pmf constants. */
2448 }
2449 else
2450 {
2453 }
2454 }
2462 /* Start by extracting all the information from the PMF itself. */
2467 {
2480 }
2482 /* Convert down to the right base before using the instance. A
2483 special case is that in a pointer to member of class C, C may
2484 be incomplete. In that case, the function will of course be
2485 a member of C, and no conversion is required. In fact,
2486 lookup_base will fail in that case, because incomplete
2487 classes do not have BINFOs. */
2491 {
2498 }
2499 /* ...and then the delta in the PMF. */
2503 /* Hand back the adjusted 'this' argument to our caller. */
2506 /* Next extract the vtable pointer from the object. */
2508 instance_ptr);
2511 /* Finally, extract the function pointer from the vtable. */
2517 /* When using function descriptors, the address of the
2518 vtable entry is treated as a function pointer. */
2526 /* Make sure this doesn't get evaluated first inside one of the
2527 branches of the COND_EXPR. */
2533 }
2535 }
2537 tree
2539 {
2541 tree coerced_params;
2546 /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2547 expressions, like those used for ObjC messenger dispatches. */
2550 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2551 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */
2557 {
2563 /* Convert anything with function type to a pointer-to-function. */
2567 /* Differs from default_conversion by not setting TREE_ADDRESSABLE
2568 (because calling an inline function does not mean the function
2569 needs to be separately compiled). */
2573 else
2575 }
2576 else
2577 {
2581 }
2589 {
2592 original);
2594 }
2601 || is_method
2603 {
2606 }
2608 /* fntype now gets the type of function pointed to. */
2611 /* Convert the parameters to the types declared in the
2612 function prototype, or apply default promotions. */
2619 /* Check for errors in format strings and inappropriately
2620 null parameters. */
2626 }
2627 \f
2628 /* Convert the actual parameter expressions in the list VALUES
2629 to the types in the list TYPELIST.
2630 If parmdecls is exhausted, or when an element has NULL as its type,
2631 perform the default conversions.
2633 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages.
2635 This is also where warnings about wrong number of args are generated.
2637 Return a list of expressions for the parameters as converted.
2639 Both VALUES and the returned value are chains of TREE_LIST nodes
2640 with the elements of the list in the TREE_VALUE slots of those nodes.
2642 In C++, unspecified trailing parameters can be filled in with their
2643 default arguments, if such were specified. Do so here. */
2645 static tree
2647 {
2653 /* Argument passing is always copy-initialization. */
2657 {
2659 {
2663 else
2665 }
2666 else
2668 }
2671 valtail;
2673 {
2681 {
2683 {
2686 }
2687 else
2689 /* In case anybody wants to know if this argument
2690 list is valid. */
2694 }
2696 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2697 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */
2704 {
2709 }
2715 {
2716 /* Formal parm type is specified by a function prototype. */
2717 tree parmval;
2720 {
2724 else
2727 }
2728 else
2729 {
2730 parmval = convert_for_initialization
2734 }
2740 }
2741 else
2742 {
2745 /* Don't do ellipsis conversion for __built_in_constant_p
2746 as this will result in spurious warnings for non-POD
2747 types. */
2749 else
2753 }
2757 }
2760 {
2761 /* See if there are default arguments that can be used. */
2764 {
2766 {
2767 tree parmval
2777 /* ends with `...'. */
2780 }
2781 }
2782 else
2783 {
2785 {
2788 }
2789 else
2792 }
2793 }
2796 }
2797 \f
2798 /* Build a binary-operation expression, after performing default
2799 conversions on the operands. CODE is the kind of expression to build. */
2801 tree
2804 {
2805 tree orig_arg1;
2806 tree orig_arg2;
2807 tree expr;
2813 {
2819 }
2823 else
2825 overloaded_p);
2831 }
2833 /* Build a binary-operation expression without default conversions.
2834 CODE is the kind of expression to build.
2835 This function differs from `build' in several ways:
2836 the data type of the result is computed and recorded in it,
2837 warnings are generated if arg data types are invalid,
2838 special handling for addition and subtraction of pointers is known,
2839 and some optimization is done (operations on narrow ints
2840 are done in the narrower type when that gives the same result).
2841 Constant folding is also done before the result is returned.
2843 Note that the operands will never have enumeral types
2844 because either they have just had the default conversions performed
2845 or they have both just been converted to some other type in which
2846 the arithmetic is to be done.
2848 C++: must do special pointer arithmetic when implementing
2849 multiple inheritance, and deal with pointer to member functions. */
2851 tree
2854 {
2860 /* Expression code to give to the expression when it is built.
2861 Normally this is CODE, which is what the caller asked for,
2862 but in some special cases we change it. */
2865 /* Data type in which the computation is to be performed.
2866 In the simplest cases this is the common type of the arguments. */
2869 /* Nonzero means operands have already been type-converted
2870 in whatever way is necessary.
2871 Zero means they need to be converted to RESULT_TYPE. */
2874 /* Nonzero means create the expression with this type, rather than
2875 RESULT_TYPE. */
2878 /* Nonzero means after finally constructing the expression
2879 convert it to this type. */
2882 tree result;
2884 /* Nonzero if this is an operation like MIN or MAX which can
2885 safely be computed in short if both args are promoted shorts.
2886 Also implies COMMON.
2887 -1 indicates a bitwise operation; this makes a difference
2888 in the exact conditions for when it is safe to do the operation
2889 in a narrower mode. */
2892 /* Nonzero if this is a comparison operation;
2893 if both args are promoted shorts, compare the original shorts.
2894 Also implies COMMON. */
2897 /* Nonzero if this is a right-shift operation, which can be computed on the
2898 original short and then promoted if the operand is a promoted short. */
2901 /* Nonzero means set RESULT_TYPE to the common type of the args. */
2904 /* True if both operands have arithmetic type. */
2907 /* Apply default conversions. */
2914 {
2919 }
2920 else
2921 {
2926 }
2928 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
2932 /* DTRT if one side is an overloaded function, but complain about it. */
2934 {
2937 {
2941 }
2942 }
2944 {
2947 {
2951 }
2952 }
2957 /* The expression codes of the data types of the arguments tell us
2958 whether the arguments are integers, floating, pointers, etc. */
2962 /* If an error was already reported for one of the arguments,
2963 avoid reporting another error. */
2970 {
2973 }
2976 {
2978 /* Handle the pointer + int case. */
2983 else
2988 /* Subtraction of two similar pointers.
2989 We must subtract them as integers, then divide by object size. */
2994 /* Handle pointer minus int. Just like pointer plus int. */
2997 else
3014 {
3027 else
3028 /* When dividing two signed integers, we have to promote to int.
3029 unless we divide by a constant != -1. Note that default
3030 conversion will have been performed on the operands at this
3031 point, so we have to dig out the original type to find out if
3032 it was unsigned. */
3039 }
3058 {
3059 /* Although it would be tempting to shorten always here, that loses
3060 on some targets, since the modulo instruction is undefined if the
3061 quotient can't be represented in the computation mode. We shorten
3062 only if unsigned or if dividing by something we know != -1. */
3068 }
3078 /* Shift operations: result has same type as first operand;
3079 always convert second operand to int.
3080 Also set SHORT_SHIFT if shifting rightward. */
3084 {
3087 {
3090 else
3091 {
3096 }
3097 }
3098 /* Convert the shift-count to an integer, regardless of
3099 size of value being shifted. */
3102 /* Avoid converting op1 to result_type later. */
3104 }
3109 {
3112 {
3117 }
3118 /* Convert the shift-count to an integer, regardless of
3119 size of value being shifted. */
3122 /* Avoid converting op1 to result_type later. */
3124 }
3130 {
3133 {
3140 }
3141 /* Convert the shift-count to an integer, regardless of
3142 size of value being shifted. */
3145 }
3175 {
3178 }
3180 {
3183 }
3185 {
3189 }
3194 {
3195 /* E will be the final comparison. */
3196 tree e;
3197 /* E1 and E2 are for scratch. */
3198 tree e1;
3199 tree e2;
3200 tree pfn0;
3201 tree pfn1;
3202 tree delta0;
3203 tree delta1;
3210 /* We generate:
3212 (op0.pfn == op1.pfn
3213 && (!op0.pfn || op0.delta == op1.delta))
3215 The reason for the `!op0.pfn' bit is that a NULL
3216 pointer-to-member is any member with a zero PFN; the
3217 DELTA field is unspecified. */
3221 delta_identifier);
3223 delta_identifier);
3226 pfn0,
3228 integer_zero_node));
3235 }
3236 else
3237 {
3240 type1));
3243 type0));
3244 }
3281 {
3284 }
3286 {
3289 }
3301 {
3304 }
3310 }
3316 else
3317 {
3319 /* Vector arithmetic is only allowed when both sides are vectors. */
3321 {
3325 {
3328 }
3330 }
3331 }
3332 /* Determine the RESULT_TYPE, if it is not already known. */
3334 && arithmetic_types_p
3339 {
3343 }
3345 /* If we're in a template, the only thing we need to know is the
3346 RESULT_TYPE. */
3353 {
3356 /* For certain operations (which identify themselves by shorten != 0)
3357 if both args were extended from the same smaller type,
3358 do the arithmetic in that type and then extend.
3360 shorten !=0 and !=1 indicates a bitwise operation.
3361 For them, this optimization is safe only if
3362 both args are zero-extended or both are sign-extended.
3363 Otherwise, we might change the result.
3364 Eg, (short)-1 | (unsigned short)-1 is (int)-1
3365 but calculated in (unsigned short) it would be (unsigned short)-1. */
3368 {
3372 /* UNS is 1 if the operation to be done is an unsigned one. */
3374 tree type;
3378 /* Handle the case that OP0 does not *contain* a conversion
3379 but it *requires* conversion to FINAL_TYPE. */
3386 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */
3388 /* For bitwise operations, signedness of nominal type
3389 does not matter. Consider only how operands were extended. */
3393 /* Note that in all three cases below we refrain from optimizing
3394 an unsigned operation on sign-extended args.
3395 That would not be valid. */
3397 /* Both args variable: if both extended in same way
3398 from same width, do it in that width.
3399 Do it unsigned if args were zero-extended. */
3406 result_type = c_common_signed_or_unsigned_type
3424 }
3426 /* Shifts can be shortened if shifting right. */
3429 {
3439 /* We can shorten only if the shift count is less than the
3440 number of bits in the smaller type size. */
3442 /* If arg is sign-extended and then unsigned-shifted,
3443 we can simulate this with a signed shift in arg's type
3444 only if the extended result is at least twice as wide
3445 as the arg. Otherwise, the shift could use up all the
3446 ones made by sign-extension and bring in zeros.
3447 We can't optimize that case at all, but in most machines
3448 it never happens because available widths are 2**N. */
3450 || unsigned_arg
3453 {
3454 /* Do an unsigned shift if the operand was zero-extended. */
3455 result_type
3458 /* Convert value-to-be-shifted to that type. */
3462 }
3463 }
3465 /* Comparison operations are shortened too but differently.
3466 They identify themselves by setting short_compare = 1. */
3469 {
3470 /* Don't write &op0, etc., because that would prevent op0
3471 from being kept in a register.
3472 Instead, make copies of the our local variables and
3473 pass the copies by reference, then copy them back afterward. */
3476 tree val
3483 }
3486 && warn_sign_compare
3487 /* Do not warn until the template is instantiated; we cannot
3488 bound the ranges of the arguments until that point. */
3490 {
3498 /* Check for comparison of different enum types. */
3503 {
3506 }
3508 /* Give warnings for comparisons between signed and unsigned
3509 quantities that may fail. */
3510 /* Do the checking based on the original operand trees, so that
3511 casts will be considered, but default promotions won't be. */
3513 /* Do not warn if the comparison is being done in a signed type,
3514 since the signed type will only be chosen if it can represent
3515 all the values of the unsigned type. */
3518 /* Do not warn if both operands are unsigned. */
3521 /* Do not warn if the signed quantity is an unsuffixed
3522 integer literal (or some static constant expression
3523 involving such literals or a conditional expression
3524 involving such literals) and it is non-negative. */
3528 /* Do not warn if the comparison is an equality operation,
3529 the unsigned quantity is an integral constant and it does
3530 not use the most significant bit of result_type. */
3539 else
3542 /* Warn if two unsigned values are being compared in a size
3543 larger than their original size, and one (and only one) is the
3544 result of a `~' operator. This comparison will always fail.
3546 Also warn if one operand is a constant, and the constant does not
3547 have all bits set that are set in the ~ operand when it is
3548 extended. */
3552 {
3559 {
3560 tree primop;
3566 {
3570 }
3571 else
3572 {
3576 }
3581 {
3585 }
3586 }
3593 }
3594 }
3595 }
3597 /* If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
3598 Then the expression will be built.
3599 It will be given type FINAL_TYPE if that is nonzero;
3600 otherwise, it will be given type RESULT_TYPE. */
3602 /* Issue warnings about peculiar, but valid, uses of NULL. */
3604 and ||, so NULL is no exception. */
3609 /* Or vice versa. */
3612 /* Or, both are NULL and the operation was not a comparison. */
3615 /* Some sort of arithmetic operation involving NULL was
3616 performed. Note that pointer-difference and pointer-addition
3617 have already been handled above, and so we don't end up here in
3618 that case. */
3622 {
3630 }
3640 }
3641 \f
3642 /* Return a tree for the sum or difference (RESULTCODE says which)
3643 of pointer PTROP and integer INTOP. */
3645 static tree
3647 {
3650 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type)
3651 in certain circumstance (when it's valid to do so). So we need
3652 to make sure it's complete. We don't need to check here, if we
3653 can actually complete it at all, as those checks will be done in
3654 pointer_int_sum() anyway. */
3659 }
3661 /* Return a tree for the difference of pointers OP0 and OP1.
3662 The resulting tree has type int. */
3664 static tree
3666 {
3667 tree result;
3675 {
3682 }
3684 /* First do the subtraction as integers;
3685 then drop through to build the divide operator. */
3691 /* This generates an error if op1 is a pointer to an incomplete type. */
3699 /* Do the division. */
3703 }
3704 \f
3705 /* Construct and perhaps optimize a tree representation
3706 for a unary operation. CODE, a tree_code, specifies the operation
3707 and XARG is the operand. */
3709 tree
3711 {
3713 tree exp;
3717 {
3722 }
3726 /* [expr.unary.op] says:
3728 The address of an object of incomplete type can be taken.
3730 (And is just the ordinary address operator, not an overloaded
3731 "operator &".) However, if the type is a template
3732 specialization, we must complete the type at this point so that
3733 an overloaded "operator &" will be available if required. */
3740 else
3744 {
3745 /* A pointer to member-function can be formed only by saying
3746 &X::mf. */
3749 {
3752 {
3754 xarg);
3758 }
3759 else
3760 {
3763 xarg);
3765 }
3766 }
3769 {
3774 {
3775 /* A single non-static member, make sure we don't allow a
3776 pointer-to-member. */
3781 }
3782 }
3786 }
3794 }
3796 /* Like c_common_truthvalue_conversion, but handle pointer-to-member
3797 constants, where a null value is represented by an INTEGER_CST of
3798 -1. */
3800 tree
3802 {
3806 else
3808 }
3810 /* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */
3812 tree
3814 {
3815 tree t;
3821 }
3823 /* Return an ADDR_EXPR giving the address of T. This function
3824 attempts no optimizations or simplifications; it is a low-level
3825 primitive. */
3827 tree
3829 {
3830 tree addr;
3838 }
3840 /* Return a NOP_EXPR converting EXPR to TYPE. */
3842 tree
3844 {
3848 }
3850 /* C++: Must handle pointers to members.
3852 Perhaps type instantiation should be extended to handle conversion
3853 from aggregates to types we don't yet know we want? (Or are those
3854 cases typically errors which should be reported?)
3856 NOCONVERT nonzero suppresses the default promotions
3857 (such as from short to int). */
3859 tree
3861 {
3862 /* No default_conversion here. It causes trouble for ADDR_EXPR. */
3866 tree val;
3874 ? CONVERT_EXPR
3877 {
3880 }
3883 {
3886 {
3888 /* Unary plus (but not unary minus) is allowed on pointers. */
3896 else
3897 {
3901 /* Make sure the result is not an lvalue: a unary plus or minus
3902 expression is always a rvalue. */
3904 }
3905 }
3910 {
3914 }
3930 /* Conjugating a real value is a no-op, but allow it anyway. */
3952 {
3955 }
3956 else
3963 {
3966 }
3967 else
3974 /* Handle complex lvalues (when permitted)
3975 by reduction to simpler cases. */
3981 /* Increment or decrement the real part of the value,
3982 and don't change the imaginary part. */
3984 {
3992 }
3994 /* Report invalid types. */
3998 {
4005 else
4008 }
4010 /* Report something read-only. */
4019 {
4020 tree inc;
4026 /* ARM $5.2.5 last annotation says this should be forbidden. */
4032 /* Compute the increment. */
4035 {
4050 }
4051 else
4056 /* Handle incrementing a cast-expression. */
4059 {
4067 {
4074 else
4085 /* Eliminate warning about unused result of + or -. */
4088 }
4092 }
4094 /* Complain about anything else that is not a true lvalue. */
4100 /* Forbid using -- on `bool'. */
4102 {
4104 {
4107 }
4109 }
4110 else
4115 }
4118 /* Note that this operation never does default_conversion
4119 regardless of NOCONVERT. */
4127 {
4131 }
4133 /* ARM $3.4 */
4136 /* Let &* cancel out to simplify resulting code. */
4138 {
4139 /* We don't need to have `current_class_ptr' wrapped in a
4140 NON_LVALUE_EXPR node. */
4146 {
4149 }
4150 else
4151 /* Don't let this be an lvalue. */
4154 }
4156 /* Uninstantiated types are all functions. Taking the
4157 address of a function is a no-op, so just return the
4158 argument. */
4165 {
4166 /* They're trying to take the address of a unique non-static
4167 member function. This is ill-formed (except in MS-land),
4168 but let's try to DTRT.
4169 Note: We only handle unique functions here because we don't
4170 want to complain if there's a static overload; non-unique
4171 cases will be handled by instantiate_type. But we need to
4172 handle this case here to allow casts on the resulting PMF.
4173 We could defer this in non-MS mode, but it's easier to give
4174 a useful error here. */
4176 /* Inside constant member functions, the `this' pointer
4177 contains an extra const qualifier. TYPE_MAIN_VARIANT
4178 is used here to remove this const from the diagnostics
4179 and the created OFFSET_REF. */
4184 {
4188 /* An expression like &memfn. */
4190 " or parenthesized non-static member function to form"
4193 else
4195 " function to form a pointer to member function."
4198 }
4200 }
4202 offset_ref:
4206 /* Handle complex lvalues (when permitted)
4207 by reduction to simpler cases. */
4213 {
4230 /* Turn a reference to a non-static data member into a
4231 pointer-to-member. */
4232 {
4233 tree type;
4234 tree t;
4241 {
4244 }
4250 }
4254 }
4256 /* Anything not already handled and not a true memory reference
4257 is an error. */
4261 /* Permit users to take the address of a compound-literal
4262 with sufficient simple elements. */
4270 /* In a template, we are processing a non-dependent expression
4271 so we can just form an ADDR_EXPR with the correct type. */
4273 {
4278 }
4280 /* If the user has taken the address of the compound literal,
4281 create a variable to contain the value of the literal and
4282 then return the address of that variable. */
4284 {
4285 tree var;
4292 /* Since each compound literal is unique, pushdecl should
4293 never find a pre-existing variable with the same
4294 name. */
4296 }
4299 {
4303 }
4305 {
4308 /* We can only get here with a single static member
4309 function. */
4315 /* Do not lose object's side effects. */
4318 }
4320 {
4324 }
4325 else
4326 {
4332 }
4336 {
4340 }
4346 }
4349 {
4353 }
4357 }
4359 /* Apply unary lvalue-demanding operator CODE to the expression ARG
4360 for certain kinds of expressions which are not really lvalues
4361 but which we can accept as lvalues.
4363 If ARG is not a kind of expression we can handle, return
4364 NULL_TREE. */
4366 tree
4368 {
4369 /* Inside a template, making these kinds of adjustments is
4370 pointless; we are only concerned with the type of the
4371 expression. */
4375 /* Handle (a, b) used as an "lvalue". */
4377 {
4381 }
4383 /* Handle (a ? b : c) used as an "lvalue". */
4388 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */
4392 {
4395 {
4399 }
4400 return unary_complex_lvalue
4402 }
4407 /* Handle (a = b) used as an "lvalue" for `&'. */
4410 {
4416 }
4423 /* We permit compiler to make function calls returning
4424 objects of aggregate type look like lvalues. */
4425 {
4432 {
4435 else
4438 }
4443 }
4445 /* Don't let anything else be handled specially. */
4447 }
4448 \f
4449 /* Mark EXP saying that we need to be able to take the
4450 address of it; it should not be allocated in a register.
4451 Value is true if successful.
4453 C++: we do not allow `current_class_ptr' to be addressable. */
4455 bool
4457 {
4462 {
4473 {
4477 }
4478 /* Fall through. */
4481 /* Caller should not be trying to mark initialized
4482 constant fields addressable. */
4487 /* Fall through. */
4493 {
4495 {
4496 error
4499 }
4500 else
4501 warning
4503 }
4522 }
4523 }
4524 \f
4525 /* Build and return a conditional expression IFEXP ? OP1 : OP2. */
4527 tree
4529 {
4533 tree expr;
4536 {
4537 /* The standard says that the expression is type-dependent if
4538 IFEXP is type-dependent, even though the eventual type of the
4539 expression doesn't dependent on IFEXP. */
4541 /* As a GNU extension, the middle operand may be omitted. */
4549 }
4556 }
4557 \f
4558 /* Given a list of expressions, return a compound expression
4559 that performs them all and returns the value of the last of them. */
4562 {
4566 {
4572 }
4575 }
4577 /* Handle overloading of the ',' operator when needed. */
4579 tree
4581 {
4582 tree result;
4587 {
4593 }
4604 }
4606 /* Build a compound expression. */
4608 tree
4610 {
4617 {
4618 /* If the rhs is a TARGET_EXPR, then build the compound
4619 expression inside the target_expr's initializer. This
4620 helps the compiler to eliminate unnecessary temporaries. */
4627 }
4630 }
4632 /* Issue a diagnostic message if casting from SRC_TYPE to DEST_TYPE
4633 casts away constness. DIAG_FN gives the function to call if we
4634 need to issue a diagnostic; if it is NULL, no diagnostic will be
4635 issued. DESCRIPTION explains what operation is taking place. */
4637 static void
4641 {
4645 }
4647 /* Convert EXPR (an expression with pointer-to-member type) to TYPE
4648 (another pointer-to-member type in the same hierarchy) and return
4649 the converted expression. If ALLOW_INVERSE_P is permitted, a
4650 pointer-to-derived may be converted to pointer-to-base; otherwise,
4651 only the other direction is permitted. If C_CAST_P is true, this
4652 conversion is taking place as part of a C-style cast. */
4654 tree
4657 {
4659 {
4660 tree delta;
4666 allow_inverse_p,
4667 c_cast_p);
4671 delta);
4673 }
4674 else
4677 }
4679 /* If EXPR is an INTEGER_CST and ORIG is an arithmetic constant, return
4680 a version of EXPR that has TREE_OVERFLOW and/or TREE_CONSTANT_OVERFLOW
4681 set iff they are set in ORIG. Otherwise, return EXPR unchanged. */
4683 static tree
4685 {
4692 {
4694 /* Ensure constant sharing. */
4698 else
4699 {
4700 /* Avoid clobbering a shared constant. */
4705 }
4706 }
4708 }
4710 /* Perform a static_cast from EXPR to TYPE. When C_CAST_P is true,
4711 this static_cast is being attempted as one of the possible casts
4712 allowed by a C-style cast. (In that case, accessibility of base
4713 classes is not considered, and it is OK to cast away
4714 constness.) Return the result of the cast. *VALID_P is set to
4715 indicate whether or not the cast was valid. */
4717 static tree
4720 {
4721 tree intype;
4722 tree result;
4723 tree orig;
4727 /* Assume the cast is valid. */
4732 /* Determine what to do when casting away constness. */
4734 {
4735 /* C-style casts are allowed to cast away constness. With
4736 WARN_CAST_QUAL, we still want to issue a warning. */
4739 }
4740 else
4741 {
4742 /* A static_cast may not cast away constness. */
4745 }
4747 /* [expr.static.cast]
4749 An lvalue of type "cv1 B", where B is a class type, can be cast
4750 to type "reference to cv2 D", where D is a class derived (clause
4751 _class.derived_) from B, if a valid standard conversion from
4752 "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the
4753 same cv-qualification as, or greater cv-qualification than, cv1,
4754 and B is not a virtual base class of D. */
4755 /* We check this case before checking the validity of "TYPE t =
4756 EXPR;" below because for this case:
4758 struct B {};
4759 struct D : public B { D(const B&); };
4760 extern B& b;
4761 void f() { static_cast<const D&>(b); }
4763 we want to avoid constructing a new D. The standard is not
4764 completely clear about this issue, but our interpretation is
4765 consistent with other compilers. */
4774 && (c_cast_p
4776 {
4777 tree base;
4779 /* There is a standard conversion from "D*" to "B*" even if "B"
4780 is ambiguous or inaccessible. If this is really a
4781 static_cast, then we check both for inaccessibility and
4782 ambiguity. However, if this is a static_cast being performed
4783 because the user wrote a C-style cast, then accessibility is
4784 not considered. */
4787 NULL);
4789 /* Convert from "B*" to "D*". This function will check that "B"
4790 is not a virtual base of "D". */
4793 /* Convert the pointer to a reference -- but then remember that
4794 there are no expressions with reference type in C++. */
4796 }
4800 /* [expr.static.cast]
4802 An expression e can be explicitly converted to a type T using a
4803 static_cast of the form static_cast<T>(e) if the declaration T
4804 t(e);" is well-formed, for some invented temporary variable
4805 t. */
4807 c_cast_p);
4809 {
4812 /* Ignore any integer overflow caused by the cast. */
4815 /* [expr.static.cast]
4817 If T is a reference type, the result is an lvalue; otherwise,
4818 the result is an rvalue. */
4822 }
4824 /* [expr.static.cast]
4826 Any expression can be explicitly converted to type cv void. */
4830 /* [expr.static.cast]
4832 The inverse of any standard conversion sequence (clause _conv_),
4833 other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer
4834 (_conv.array_), function-to-pointer (_conv.func_), and boolean
4835 (_conv.bool_) conversions, can be performed explicitly using
4836 static_cast subject to the restriction that the explicit
4837 conversion does not cast away constness (_expr.const.cast_), and
4838 the following additional rules for specific cases: */
4839 /* For reference, the conversions not excluded are: integral
4840 promotions, floating point promotion, integral conversions,
4841 floating point conversions, floating-integral conversions,
4842 pointer conversions, and pointer to member conversions. */
4843 /* DR 128
4845 A value of integral _or enumeration_ type can be explicitly
4846 converted to an enumeration type. */
4847 /* The effect of all that is that any conversion between any two
4848 types which are integral, floating, or enumeration types can be
4849 performed. */
4852 {
4855 /* Ignore any integer overflow caused by the cast. */
4858 }
4867 {
4868 tree base;
4874 NULL);
4876 }
4880 {
4881 tree c1;
4882 tree c2;
4883 tree t1;
4884 tree t2;
4890 {
4891 t1 = (build_ptrmem_type
4894 t2 = (build_ptrmem_type
4897 }
4898 else
4899 {
4902 }
4904 {
4907 desc);
4909 c_cast_p);
4910 }
4911 }
4913 /* [expr.static.cast]
4915 An rvalue of type "pointer to cv void" can be explicitly
4916 converted to a pointer to object type. A value of type pointer
4917 to object converted to "pointer to cv void" and back to the
4918 original pointer type will have its original value. */
4922 {
4926 }
4930 }
4932 /* Return an expression representing static_cast<TYPE>(EXPR). */
4934 tree
4936 {
4937 tree result;
4944 {
4946 /* We don't know if it will or will not have side effects. */
4949 }
4951 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4952 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4965 }
4967 /* EXPR is an expression with member function or pointer-to-member
4968 function type. TYPE is a pointer type. Converting EXPR to TYPE is
4969 not permitted by ISO C++, but we accept it in some modes. If we
4970 are not in one of those modes, issue a diagnostic. Return the
4971 converted expression. */
4973 tree
4975 {
4976 tree intype;
4977 tree decl;
4990 else
4991 {
4995 }
4998 }
5000 /* Return a representation for a reinterpret_cast from EXPR to TYPE.
5001 If C_CAST_P is true, this reinterpret cast is being done as part of
5002 a C-style cast. If VALID_P is non-NULL, *VALID_P is set to
5003 indicate whether or not reinterpret_cast was valid. */
5005 static tree
5008 {
5009 tree intype;
5011 /* Assume the cast is invalid. */
5020 /* [expr.reinterpret.cast]
5021 An lvalue expression of type T1 can be cast to the type
5022 "reference to T2" if an expression of type "pointer to T1" can be
5023 explicitly converted to the type "pointer to T2" using a
5024 reinterpret_cast. */
5026 {
5028 {
5033 }
5035 /* Warn about a reinterpret_cast from "A*" to "B&" if "A" and
5036 "B" are related class types; the reinterpret_cast does not
5037 adjust the pointer. */
5046 expr = build_reinterpret_cast_1
5048 valid_p);
5052 }
5054 /* As a G++ extension, we consider conversions from member
5055 functions, and pointers to member functions to
5056 pointer-to-function and pointer-to-void types. If
5057 -Wno-pmf-conversions has not been specified,
5058 convert_member_func_to_ptr will issue an error message. */
5066 /* If the cast is not to a reference type, the lvalue-to-rvalue,
5067 array-to-pointer, and function-to-pointer conversions are
5068 performed. */
5071 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5072 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5082 /* [expr.reinterpret.cast]
5083 A pointer can be converted to any integral type large enough to
5084 hold it. */
5086 {
5090 }
5091 /* [expr.reinterpret.cast]
5092 A value of integral or enumeration type can be explicitly
5093 converted to a pointer. */
5095 /* OK */
5096 ;
5102 {
5108 /* Warn about possible alignment problems. */
5119 /* We need to strip nops here, because the frontend likes to
5120 create (int *)&a for array-to-pointer decay, instead of &a[0]. */
5125 }
5128 {
5130 /* Only issue a warning, as we have always supported this
5131 where possible, and it is necessary in some cases. DR 195
5132 addresses this issue, but as of 2004/10/26 is still in
5133 drafting. */
5136 }
5141 else
5142 {
5147 }
5150 }
5152 tree
5154 {
5159 {
5164 /* There might turn out to be side effects inside expr. */
5167 }
5171 }
5173 /* Perform a const_cast from EXPR to TYPE. If the cast is valid,
5174 return an appropriate expression. Otherwise, return
5175 error_mark_node. If the cast is not valid, and COMPLAIN is true,
5176 then a diagnostic will be issued. If VALID_P is non-NULL, we are
5177 performing a C-style cast, its value upon return will indicate
5178 whether or not the conversion succeeded. */
5180 static tree
5183 {
5184 tree src_type;
5185 tree reference_type;
5187 /* Callers are responsible for handling error_mark_node as a
5188 destination type. */
5190 /* In a template, callers should be building syntactic
5191 representations of casts, not using this machinery. */
5194 /* Assume the conversion is invalid. */
5199 {
5202 "which is not a pointer, "
5205 }
5208 {
5213 }
5216 /* Expressions do not really have reference types. */
5220 /* [expr.const.cast]
5222 An lvalue of type T1 can be explicitly converted to an lvalue of
5223 type T2 using the cast const_cast<T2&> (where T1 and T2 are object
5224 types) if a pointer to T1 can be explicitly converted to the type
5225 pointer to T2 using a const_cast. */
5227 {
5230 {
5235 }
5238 }
5239 else
5240 {
5242 /* If the destination type is not a reference type, the
5243 lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5244 conversions are performed. */
5248 }
5252 {
5254 {
5256 /* This cast is actually a C-style cast. Issue a warning if
5257 the user is making a potentially unsafe cast. */
5260 warning0,
5262 }
5264 {
5268 }
5269 else
5270 {
5272 /* build_c_cast puts on a NOP_EXPR to make the result not an
5273 lvalue. Strip such NOP_EXPRs if VALUE is being used in
5274 non-lvalue context. */
5279 }
5280 }
5286 }
5288 tree
5290 {
5295 {
5300 /* There might turn out to be side effects inside expr. */
5303 }
5307 }
5309 /* Build an expression representing an explicit C-style cast to type
5310 TYPE of expression EXPR. */
5312 tree
5314 {
5316 tree result;
5323 {
5326 /* We don't know if it will or will not have side effects. */
5329 }
5331 /* Casts to a (pointer to a) specific ObjC class (or 'id' or
5332 'Class') should always be retained, because this information aids
5333 in method lookup. */
5338 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5339 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5346 {
5347 /* Allow casting from T1* to T2[] because Cfront allows it.
5348 NIHCL uses it. It is not valid ISO C++ however. */
5350 {
5353 }
5354 else
5355 {
5358 }
5359 }
5363 {
5366 }
5368 /* A C-style cast can be a const_cast. */
5374 /* Or a static cast. */
5377 /* Or a reinterpret_cast. */
5381 /* The static_cast or reinterpret_cast may be followed by a
5382 const_cast. */
5384 /* A valid cast may result in errors if, for example, a
5385 conversion to am ambiguous base class is required. */
5387 {
5388 tree result_type;
5390 /* Non-class rvalues always have cv-unqualified type. */
5396 /* If the type of RESULT does not match TYPE, perform a
5397 const_cast to make it match. If the static_cast or
5398 reinterpret_cast succeeded, we will differ by at most
5399 cv-qualification, so the follow-on const_cast is guaranteed
5400 to succeed. */
5402 {
5405 }
5407 }
5410 }
5411 \f
5412 /* Build an assignment expression of lvalue LHS from value RHS.
5413 MODIFYCODE is the code for a binary operator that we use
5414 to combine the old value of LHS with RHS to get the new value.
5415 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
5417 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */
5419 tree
5421 {
5422 tree result;
5429 /* Avoid duplicate error messages from operands that had errors. */
5433 /* Handle control structure constructs used as "lvalues". */
5435 {
5436 /* Handle --foo = 5; as these are valid constructs in C++. */
5444 lhs,
5448 /* Handle (a, b) used as an "lvalue". */
5469 /* MIN_EXPR and MAX_EXPR are currently only permitted as lvalues,
5470 when neither operand has side-effects. */
5479 boolean_type_node,
5484 /* Fall through. */
5486 /* Handle (a ? b : c) used as an "lvalue". */
5488 {
5489 /* Produce (a ? (b = rhs) : (c = rhs))
5490 except that the RHS goes through a save-expr
5491 so the code to compute it is only emitted once. */
5492 tree cond;
5497 /* Check this here to avoid odd errors when trying to convert
5498 a throw to the type of the COND_EXPR. */
5502 cond = build_conditional_expr
5513 /* Make sure the code to compute the rhs comes out
5514 before the split. */
5518 }
5522 }
5525 {
5527 {
5529 /* Call convert to generate an error; see PR 11063. */
5534 }
5537 else
5538 {
5545 }
5546 }
5547 else
5548 {
5554 {
5555 /* `operator=' is not an inheritable operator. */
5558 else
5559 {
5566 }
5568 }
5569 else
5570 {
5571 /* A binary op has been requested. Combine the old LHS
5572 value with the RHS producing the value we should actually
5573 store into the LHS. */
5579 {
5583 }
5585 /* Now it looks like a plain assignment. */
5587 }
5590 }
5592 /* The left-hand side must be an lvalue. */
5596 /* Warn about modifying something that is `const'. Don't warn if
5597 this is initialization. */
5600 /* Functions are not modifiable, even though they are
5601 lvalues. */
5604 /* If it's an aggregate and any field is const, then it is
5605 effectively const. */
5610 /* If storing into a structure or union member, it has probably been
5611 given type `int'. Compute the type that would go with the actual
5612 amount of storage the member occupies. */
5618 {
5621 /* If storing in a field that is in actuality a short or narrower
5622 than one, we must store in the field in its actual type. */
5625 {
5626 /* Avoid warnings converting integral types back into enums for
5627 enum bit fields. */
5630 {
5634 }
5637 }
5638 }
5640 /* Convert new value to destination type. */
5643 {
5648 {
5652 }
5654 /* Allow array assignment in compiler-generated code. */
5662 from_array);
5663 }
5668 else
5669 {
5670 /* Avoid warnings on enum bit fields. */
5673 {
5677 }
5678 else
5685 /* Can't initialize directly from a TARGET_EXPR, since that would
5686 cause the lhs to be constructed twice, and possibly result in
5687 accidental self-initialization. So we force the TARGET_EXPR to be
5688 expanded without a target. */
5692 }
5698 {
5703 }
5712 /* If we got the LHS in a different type for storing in,
5713 convert the result back to the nominal type of LHS
5714 so that the value we return always has the same type
5715 as the LHS argument. */
5720 {
5724 }
5727 }
5729 tree
5731 {
5737 {
5742 {
5745 }
5746 }
5748 }
5750 \f
5751 /* Get difference in deltas for different pointer to member function
5752 types. Returns an integer constant of type PTRDIFF_TYPE_NODE. If
5753 the conversion is invalid, the constant is zero. If
5754 ALLOW_INVERSE_P is true, then allow reverse conversions as well.
5755 If C_CAST_P is true this conversion is taking place as part of a
5756 C-style cast.
5758 Note that the naming of FROM and TO is kind of backwards; the return
5759 value is what we add to a TO in order to get a FROM. They are named
5760 this way because we call this function to find out how to convert from
5761 a pointer to member of FROM to a pointer to member of TO. */
5763 static tree
5767 {
5768 tree binfo;
5769 base_kind kind;
5770 tree result;
5772 /* Assume no conversion is required. */
5778 {
5781 else
5782 {
5785 /* This is a reinterpret cast, we choose to do nothing. */
5789 else
5792 }
5793 }
5797 {
5800 }
5801 else
5802 {
5805 {
5808 else
5809 {
5810 /* This is a reinterpret cast, we choose to do nothing. */
5815 }
5816 }
5817 }
5820 result));
5821 }
5823 /* Return a constructor for the pointer-to-member-function TYPE using
5824 the other components as specified. */
5826 tree
5828 {
5830 tree delta_field;
5831 tree pfn_field;
5834 /* Pull the FIELD_DECLs out of the type. */
5838 /* Make sure DELTA has the type we want. */
5841 /* Finish creating the initializer. */
5854 }
5856 /* Build a constructor for a pointer to member function. It can be
5857 used to initialize global variables, local variable, or used
5858 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we
5859 want to be.
5861 If FORCE is nonzero, then force this conversion, even if
5862 we would rather not do it. Usually set when using an explicit
5863 cast. A C-style cast is being processed iff C_CAST_P is true.
5865 Return error_mark_node, if something goes wrong. */
5867 tree
5869 {
5870 tree fn;
5871 tree pfn_type;
5872 tree to_type;
5880 /* Handle multiple conversions of pointer to member functions. */
5882 {
5885 tree n;
5894 force,
5895 c_cast_p);
5897 /* We don't have to do any conversion to convert a
5898 pointer-to-member to its own type. But, we don't want to
5899 just return a PTRMEM_CST if there's an explicit cast; that
5900 cast should make the expression an invalid template argument. */
5902 {
5907 }
5912 /* Obtain the function pointer and the current DELTA. */
5915 else
5916 {
5919 }
5921 /* Just adjust the DELTA field. */
5928 }
5930 /* Handle null pointer to member function conversions. */
5932 {
5935 integer_zero_node,
5936 pfn);
5937 }
5944 /* In a template, we will have preserved the
5945 OFFSET_REF. */
5948 }
5950 /* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST
5951 given by CST.
5953 ??? There is no consistency as to the types returned for the above
5954 values. Some code acts as if it were a sizetype and some as if it were
5955 integer_type_node. */
5957 void
5959 {
5966 /* The class that the function belongs to. */
5969 /* The class that we're creating a pointer to member of. */
5972 /* First, calculate the adjustment to the function's class. */
5978 else
5979 {
5980 /* If we're dealing with a virtual function, we have to adjust 'this'
5981 again, to point to the base which provides the vtable entry for
5982 fn; the call will do the opposite adjustment. */
5989 /* We set PFN to the vtable offset at which the function can be
5990 found, plus one (unless ptrmemfunc_vbit_in_delta, in which
5991 case delta is shifted left, and then incremented). */
5998 {
6001 integer_one_node);
6016 }
6020 }
6021 }
6023 /* Return an expression for PFN from the pointer-to-member function
6024 given by T. */
6026 static tree
6028 {
6030 {
6031 tree delta;
6032 tree pfn;
6037 }
6040 }
6042 /* Convert value RHS to type TYPE as preparation for an assignment to
6043 an lvalue of type TYPE. ERRTYPE is a string to use in error
6044 messages: "assignment", "return", etc. If FNDECL is non-NULL, we
6045 are doing the conversion in order to pass the PARMNUMth argument of
6046 FNDECL. */
6048 static tree
6051 {
6052 tree rhstype;
6055 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
6071 /* The RHS of an assignment cannot have void type. */
6073 {
6076 }
6078 /* Simplify the RHS if possible. */
6083 {
6091 else
6092 {
6098 {
6101 }
6102 }
6106 }
6108 /* [expr.ass]
6110 The expression is implicitly converted (clause _conv_) to the
6111 cv-unqualified type of the left operand.
6113 We allow bad conversions here because by the time we get to this point
6114 we are committed to doing the conversion. If we end up doing a bad
6115 conversion, convert_like will complain. */
6117 {
6118 /* When -Wno-pmf-conversions is use, we just silently allow
6119 conversions from pointers-to-members to plain pointers. If
6120 the conversion doesn't work, cp_convert will complain. */
6125 else
6126 {
6127 /* If the right-hand side has unknown type, then it is an
6128 overloaded function. Call instantiate_type to get error
6129 messages. */
6135 else
6138 }
6139 }
6141 {
6148 errtype);
6149 }
6152 }
6154 /* Convert RHS to be of type TYPE.
6155 If EXP is nonzero, it is the target of the initialization.
6156 ERRTYPE is a string to use in error messages.
6158 Two major differences between the behavior of
6159 `convert_for_assignment' and `convert_for_initialization'
6160 are that references are bashed in the former, while
6161 copied in the latter, and aggregates are assigned in
6162 the former (operator=) while initialized in the
6163 latter (X(X&)).
6165 If using constructor make sure no conversion operator exists, if one does
6166 exist, an ambiguity exists.
6168 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */
6170 tree
6173 {
6175 tree rhstype;
6178 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
6179 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */
6205 /* We accept references to incomplete types, so we can
6206 return here before checking if RHS is of complete type. */
6209 {
6210 /* This should eventually happen in convert_arguments. */
6218 {
6223 }
6225 }
6240 }
6241 \f
6242 /* If RETVAL is the address of, or a reference to, a local variable or
6243 temporary give an appropriate warning. */
6245 static void
6247 {
6252 {
6259 else
6261 }
6268 {
6271 {
6274 }
6278 {
6281 }
6282 }
6289 {
6292 whats_returned);
6293 else
6295 whats_returned);
6297 }
6298 }
6300 /* Check that returning RETVAL from the current function is valid.
6301 Return an expression explicitly showing all conversions required to
6302 change RETVAL into the function return type, and to assign it to
6303 the DECL_RESULT for the function. Set *NO_WARNING to true if
6304 code reaches end of non-void function warning shouldn't be issued
6305 on this RETURN_EXPR. */
6307 tree
6309 {
6310 tree result;
6311 /* The type actually returned by the function, after any
6312 promotions. */
6313 tree valtype;
6318 /* A `volatile' function is one that isn't supposed to return, ever.
6319 (This is a G++ extension, used to get better code for functions
6320 that call the `volatile' function.) */
6324 /* Check for various simple errors. */
6326 {
6330 }
6332 {
6334 /* If a return statement appears in a handler of the
6335 function-try-block of a constructor, the program is ill-formed. */
6338 /* You can't return a value from a constructor. */
6341 }
6344 {
6347 }
6349 /* When no explicit return-value is given in a function with a named
6350 return value, the named return value is used. */
6358 /* Check for a return statement with no return value in a function
6359 that's supposed to return a value. */
6361 {
6363 valtype);
6364 /* Clear this, so finish_function won't say that we reach the
6365 end of a non-void function (which we don't, we gave a
6366 return!). */
6368 /* And signal caller that TREE_NO_WARNING should be set on the
6369 RETURN_EXPR to avoid control reaches end of non-void function
6370 warnings in tree-cfg.c. */
6372 }
6373 /* Check for a return statement with a value in a function that
6374 isn't supposed to return a value. */
6376 {
6378 /* You can return a `void' value from a function of `void'
6379 type. In that case, we have to evaluate the expression for
6380 its side-effects. */
6382 else
6388 /* There's really no value to return, after all. */
6390 }
6392 /* Remember that this function can sometimes return without a
6393 value. */
6395 else
6396 /* Remember that this function did return a value. */
6399 /* Check for erroneous operands -- but after giving ourselves a
6400 chance to provide an error about returning a value from a void
6401 function. */
6403 {
6406 }
6408 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */
6412 && ! flag_check_new
6417 /* Effective C++ rule 15. See also start_function. */
6420 {
6423 /* The function return type must be a reference to the current
6424 class. */
6426 && same_type_ignoring_top_level_qualifiers_p
6428 {
6429 /* Returning '*this' is obviously OK. */
6432 /* If we are calling a function whose return type is the same of
6433 the current class reference, it is ok. */
6437 }
6441 }
6443 /* The fabled Named Return Value optimization, as per [class.copy]/15:
6445 [...] For a function with a class return type, if the expression
6446 in the return statement is the name of a local object, and the cv-
6447 unqualified type of the local object is the same as the function
6448 return type, an implementation is permitted to omit creating the tem-
6449 porary object to hold the function return value [...]
6451 So, if this is a value-returning function that always returns the same
6452 local variable, remember it.
6454 It might be nice to be more flexible, and choose the first suitable
6455 variable even if the function sometimes returns something else, but
6456 then we run the risk of clobbering the variable we chose if the other
6457 returned expression uses the chosen variable somehow. And people expect
6458 this restriction, anyway. (jason 2000-11-19)
6460 See finish_function and finalize_nrv for the rest of this optimization. */
6463 {
6474 (TYPE_MAIN_VARIANT
6477 else
6479 }
6481 /* We don't need to do any conversions when there's nothing being
6482 returned. */
6486 /* Do any required conversions. */
6488 /* No conversions are required. */
6489 ;
6490 else
6491 {
6492 /* The type the function is declared to return. */
6495 /* The functype's return type will have been set to void, if it
6496 was an incomplete type. Just treat this as 'return;' */
6500 /* First convert the value to the function's return type, then
6501 to the type of return value's location to handle the
6502 case that functype is smaller than the valtype. */
6503 retval = convert_for_initialization
6508 /* If the conversion failed, treat this just like `return;'. */
6511 /* We can't initialize a register from a AGGR_INIT_EXPR. */
6517 else
6519 }
6521 /* Actually copy the value returned into the appropriate location. */
6526 }
6528 \f
6529 /* Returns nonzero if the pointer-type FROM can be converted to the
6530 pointer-type TO via a qualification conversion. If CONSTP is -1,
6531 then we return nonzero if the pointers are similar, and the
6532 cv-qualification signature of FROM is a proper subset of that of TO.
6534 If CONSTP is positive, then all outer pointers have been
6535 const-qualified. */
6537 static int
6539 {
6543 {
6552 /* Const and volatile mean something different for function types,
6553 so the usual checks are not appropriate. */
6555 {
6556 /* In Objective-C++, some types may have been 'volatilized' by
6557 the compiler for EH; when comparing them here, the volatile
6558 qualification must be ignored. */
6565 {
6569 }
6573 }
6578 }
6579 }
6581 /* When comparing, say, char ** to char const **, this function takes
6582 the 'char *' and 'char const *'. Do not pass non-pointer/reference
6583 types to this function. */
6585 int
6587 {
6589 }
6591 /* Returns 1 if to and from are (possibly multi-level) pointers to the same
6592 type or inheritance-related types, regardless of cv-quals. */
6594 int
6596 {
6598 {
6599 /* Any target type is similar enough to void. */
6625 return comptypes
6628 }
6629 }
6631 /* Return true if TO and FROM (both of which are POINTER_TYPEs or
6632 pointer-to-member types) are the same, ignoring cv-qualification at
6633 all levels. */
6635 bool
6637 {
6639 {
6650 }
6651 }
6653 /* Returns the type qualifiers for this type, including the qualifiers on the
6654 elements for an array type. */
6656 int
6658 {
6663 }
6665 /* Returns nonzero if the TYPE contains a mutable member. */
6667 bool
6669 {
6673 }
6675 /* Apply the TYPE_QUALS to the new DECL. */
6676 void
6678 {
6686 {
6687 /* This was an error in C++98 (cv-qualifiers cannot be added to
6688 a function type), but DR 295 makes the code well-formed by
6689 dropping the extra qualifiers. */
6691 {
6695 }
6699 }
6701 /* Avoid setting TREE_READONLY incorrectly. */
6703 the object. */
6705 /* If the type isn't complete, we don't know yet if it will need
6706 constructing. */
6708 /* If the type has a mutable component, that component might be
6709 modified. */
6714 }
6716 /* Subroutine of casts_away_constness. Make T1 and T2 point at
6717 exemplar types such that casting T1 to T2 is casting away constness
6718 if and only if there is no implicit conversion from T1 to T2. */
6720 static void
6722 {
6726 /* [expr.const.cast]
6728 For multi-level pointer to members and multi-level mixed pointers
6729 and pointers to members (conv.qual), the "member" aspect of a
6730 pointer to member level is ignored when determining if a const
6731 cv-qualifier has been cast away. */
6732 /* [expr.const.cast]
6734 For two pointer types:
6736 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type
6737 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type
6738 K is min(N,M)
6740 casting from X1 to X2 casts away constness if, for a non-pointer
6741 type T there does not exist an implicit conversion (clause
6742 _conv_) from:
6744 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N *
6746 to
6748 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */
6751 {
6757 }
6764 else
6768 else
6776 }
6778 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
6779 constness. */
6781 static bool
6783 {
6785 {
6786 /* [expr.const.cast]
6788 Casting from an lvalue of type T1 to an lvalue of type T2
6789 using a reference cast casts away constness if a cast from an
6790 rvalue of type "pointer to T1" to the type "pointer to T2"
6791 casts away constness. */
6795 }
6798 /* [expr.const.cast]
6800 Casting from an rvalue of type "pointer to data member of X
6801 of type T1" to the type "pointer to data member of Y of type
6802 T2" casts away constness if a cast from an rvalue of type
6803 "pointer to T1" to the type "pointer to T2" casts away
6804 constness. */
6805 return casts_away_constness
6809 /* Casting away constness is only something that makes sense for
6810 pointer or reference types. */
6815 /* Top-level qualifiers don't matter. */
6823 }
6825 /* If T is a REFERENCE_TYPE return the type to which T refers.
6826 Otherwise, return T itself. */
6828 tree
6830 {
6834 }
6837 /* Return nonzero if REF is an lvalue valid for this language;
6838 otherwise, print an error message and return zero. USE says
6839 how the lvalue is being used and so selects the error message. */
6841 int
6843 {
6850 }