| blob | c7bc0609cc938d61da2315c783a8ab79a9b93765 |
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. */
63 /* Do `exp = require_complete_type (exp);' to make sure exp
64 does not have an incomplete type. (That includes void types.)
65 Returns the error_mark_node if the VALUE does not have
66 complete type when this function returns. */
68 tree
70 {
71 tree type;
78 else
84 /* First, detect a valid value with a complete type. */
90 else
92 }
94 /* Try to complete TYPE, if it is incomplete. For example, if TYPE is
95 a template instantiation, do the instantiation. Returns TYPE,
96 whether or not it could be completed, unless something goes
97 horribly wrong, in which case the error_mark_node is returned. */
99 tree
101 {
103 /* Rather than crash, we return something sure to cause an error
104 at some point. */
108 ;
110 {
115 needs_constructing
117 has_nontrivial_dtor
120 {
123 }
124 }
129 }
131 /* Like complete_type, but issue an error if the TYPE cannot be completed.
132 VALUE is used for informative diagnostics.
133 Returns NULL_TREE if the type cannot be made complete. */
135 tree
137 {
140 /* We already issued an error. */
143 {
146 }
147 else
149 }
151 /* Return truthvalue of whether type of EXP is instantiated. */
153 int
155 {
158 }
160 \f
161 /* Return the common type of two parameter lists.
162 We assume that comptypes has already been done and returned 1;
163 if that isn't so, this may crash.
165 As an optimization, free the space we allocate if the parameter
166 lists are already common. */
168 static tree
170 {
180 else
181 {
184 }
193 {
195 {
198 }
200 {
202 {
205 }
206 }
207 else
208 {
212 }
214 {
217 }
218 else
220 }
225 }
227 /* Given a type, perhaps copied for a typedef,
228 find the "original" version of it. */
229 static tree
231 {
235 {
243 }
245 }
247 /* T1 and T2 are arithmetic or enumeration types. Return the type
248 that will result from the "usual arithmetic conversions" on T1 and
249 T2 as described in [expr]. */
251 tree
253 {
256 tree attributes;
258 /* FIXME: Attributes. */
268 /* In what follows, we slightly generalize the rules given in [expr] so
269 as to deal with `long long' and `complex'. First, merge the
270 attributes. */
273 /* If one type is complex, form the common type of the non-complex
274 components, then make that complex. Use T1 or T2 if it is the
275 required type. */
277 {
280 tree subtype
287 else
289 attributes);
290 }
293 {
294 /* When we get here we should have two vectors of the same size.
295 Just prefer the unsigned one if present. */
298 else
300 }
302 /* If only one is real, use it as the result. */
308 /* Perform the integral promotions. */
310 {
313 }
315 /* Both real or both integers; use the one with greater precision. */
321 /* The types are the same; no need to do anything fancy. */
326 {
327 /* If one is a sizetype, use it so size_binop doesn't blow up. */
333 /* If one is unsigned long long, then convert the other to unsigned
334 long long. */
338 attributes);
339 /* If one is a long long, and the other is an unsigned long, and
340 long long can represent all the values of an unsigned long, then
341 convert to a long long. Otherwise, convert to an unsigned long
342 long. Otherwise, if either operand is long long, convert the
343 other to long long.
345 Since we're here, we know the TYPE_PRECISION is the same;
346 therefore converting to long long cannot represent all the values
347 of an unsigned long, so we choose unsigned long long in that
348 case. */
351 {
353 ? long_long_unsigned_type_node
356 }
358 /* Go through the same procedure, but for longs. */
362 attributes);
365 {
369 }
370 /* Otherwise prefer the unsigned one. */
373 else
375 }
376 else
377 {
381 attributes);
385 attributes);
389 attributes);
391 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of
392 the standard C++ floating-point types. Logic earlier in this
393 function has already eliminated the possibility that
394 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no
395 compelling reason to choose one or the other. */
397 }
398 }
400 /* Subroutine of composite_pointer_type to implement the recursive
401 case. See that function for documentation fo the parameters. */
403 static tree
405 {
406 tree pointee1;
407 tree pointee2;
408 tree result_type;
409 tree attributes;
411 /* Determine the types pointed to by T1 and T2. */
413 {
416 }
417 else
418 {
421 }
423 /* [expr.rel]
425 Otherwise, the composite pointer type is a pointer type
426 similar (_conv.qual_) to the type of one of the operands,
427 with a cv-qualification signature (_conv.qual_) that is the
428 union of the cv-qualification signatures of the operand
429 types. */
437 else
438 {
443 }
447 /* If the original types were pointers to members, so is the
448 result. */
450 {
457 result_type);
458 }
459 else
462 /* Merge the attributes. */
465 }
467 /* Return the composite pointer type (see [expr.rel]) for T1 and T2.
468 ARG1 and ARG2 are the values with those types. The LOCATION is a
469 string describing the current location, in case an error occurs.
471 This routine also implements the computation of a common type for
472 pointers-to-members as per [expr.eq]. */
474 tree
477 {
478 tree class1;
479 tree class2;
481 /* [expr.rel]
483 If one operand is a null pointer constant, the composite pointer
484 type is the type of the other operand. */
490 /* We have:
492 [expr.rel]
494 If one of the operands has type "pointer to cv1 void*", then
495 the other has type "pointer to cv2T", and the composite pointer
496 type is "pointer to cv12 void", where cv12 is the union of cv1
497 and cv2.
499 If either type is a pointer to void, make sure it is T1. */
501 {
502 tree t;
506 }
508 /* Now, if T1 is a pointer to void, merge the qualifiers. */
510 {
511 tree attributes;
512 tree result_type;
517 result_type
522 /* Merge the attributes. */
525 }
529 {
532 }
534 /* [expr.eq] permits the application of a pointer conversion to
535 bring the pointers to a common type. */
541 {
546 t2 = (build_pointer_type
549 t1 = (build_pointer_type
551 else
552 {
556 }
557 }
558 /* [expr.eq] permits the application of a pointer-to-member
559 conversion to change the class type of one of the types. */
563 {
571 else
572 {
576 }
577 }
580 }
582 /* Return the merged type of two types.
583 We assume that comptypes has already been done and returned 1;
584 if that isn't so, this may crash.
586 This just combines attributes and default arguments; any other
587 differences would cause the two types to compare unalike. */
589 tree
591 {
594 tree attributes;
596 /* Save time if the two types are the same. */
602 /* If one type is nonsense, use the other. */
608 /* Merge the attributes. */
620 {
623 /* For two pointers, do this recursively on the target type. */
624 {
630 else
639 }
642 {
644 tree pointee;
649 pointee);
652 }
655 {
657 /* Save space: see if the result is identical to one of the args. */
662 /* Merge the element types, and have a size if either arg has one. */
663 t1 = build_cplus_array_type
666 }
669 /* Function types: prefer the one that specified arg types.
670 If both do, merge the arg types. Also merge the return types. */
671 {
677 /* Save space: see if the result is identical to one of the args. */
683 /* Simple way if one arg fails to specify argument types. */
685 {
690 }
693 {
698 }
703 }
706 {
707 /* Get this value the long way, since TYPE_METHOD_BASETYPE
708 is just the main variant of this. */
711 tree t3;
713 /* If this was a member function type, get back to the
714 original type of type member function (i.e., without
715 the class instance variable up front. */
725 }
728 /* There is no need to merge attributes into a TYPENAME_TYPE.
729 When the type is instantiated it will have whatever
730 attributes result from the instantiation. */
734 }
740 else
742 }
744 /* Return the common type of two types.
745 We assume that comptypes has already been done and returned 1;
746 if that isn't so, this may crash.
748 This is the type for the result of most arithmetic operations
749 if the operands have the given two types. */
751 tree
753 {
757 /* If one type is nonsense, bail. */
775 else
777 }
778 \f
779 /* Compare two exception specifier types for exactness or subsetness, if
780 allowed. Returns false for mismatch, true for match (same, or
781 derived and !exact).
783 [except.spec] "If a class X ... objects of class X or any class publicly
784 and unambiguously derived from X. Similarly, if a pointer type Y * ...
785 exceptions of type Y * or that are pointers to any type publicly and
786 unambiguously derived from Y. Otherwise a function only allows exceptions
787 that have the same type ..."
788 This does not mention cv qualifiers and is different to what throw
789 [except.throw] and catch [except.catch] will do. They will ignore the
790 top level cv qualifiers, and allow qualifiers in the pointer to class
791 example.
793 We implement the letter of the standard. */
795 static bool
797 {
801 {
807 {
812 }
820 }
822 }
824 /* Return true if TYPE1 and TYPE2 are equivalent exception specifiers.
825 If EXACT is false, T2 can be stricter than T1 (according to 15.4/7),
826 otherwise it must be exact. Exception lists are unordered, but
827 we've already filtered out duplicates. Most lists will be in order,
828 we should try to make use of that. */
830 bool
832 {
833 tree probe;
834 tree base;
849 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1.
850 Count how many we find, to determine exactness. For exact matching and
851 ordered T1, T2, this is an O(n) operation, otherwise its worst case is
852 O(nm). */
854 {
856 {
861 {
864 length++;
866 }
867 }
870 }
872 }
874 /* Compare the array types T1 and T2. ALLOW_REDECLARATION is true if
875 [] can match [size]. */
877 static bool
879 {
880 tree d1;
881 tree d2;
887 /* The type of the array elements must be the same. */
897 /* If one of the arrays is dimensionless, and the other has a
898 dimension, they are of different types. However, it is valid to
899 write:
901 extern int a[];
902 int a[3];
904 by [basic.link]:
906 declarations for an array object can specify
907 array types that differ by the presence or absence of a major
908 array bound (_dcl.array_). */
912 /* Check that the dimensions are the same. */
921 {
922 /* With abi-1 we do not fold non-dependent array bounds, (and
923 consequently mangle them incorrectly). We must therefore
924 fold them here, to verify the domains have the same
925 value. */
928 }
934 }
936 /* Return true if T1 and T2 are related as allowed by STRICT. STRICT
937 is a bitwise-or of the COMPARE_* flags. */
939 bool
941 {
945 /* Suppress errors caused by previously reported errors. */
951 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the
952 current instantiation. */
954 {
959 }
962 {
967 }
969 /* If either type is the internal version of sizetype, use the
970 language version. */
984 /* Different classes of types can't be compatible. */
988 /* Qualifiers must match. For array types, we will check when we
989 recur on the array element types. */
996 /* Allow for two different type nodes which have essentially the same
997 definition. Note that we already checked for equality of the type
998 qualifiers (just above). */
1004 /* Compare the types. Break out if they could be the same. */
1006 {
1018 /* Don't check inheritance. */
1020 /* Fall through. */
1062 /* Target types must match incl. qualifiers. */
1101 }
1103 /* If we get here, we know that from a target independent POV the
1104 types are the same. Make sure the target attributes are also
1105 the same. */
1107 }
1109 /* Returns 1 if TYPE1 is at least as qualified as TYPE2. */
1111 bool
1113 {
1117 /* All qualifiers for TYPE2 must also appear in TYPE1. */
1119 }
1121 /* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is
1122 more cv-qualified that TYPE1, and 0 otherwise. */
1124 int
1126 {
1139 }
1141 /* Returns 1 if the cv-qualification signature of TYPE1 is a proper
1142 subset of the cv-qualification signature of TYPE2, and the types
1143 are similar. Returns -1 if the other way 'round, and 0 otherwise. */
1145 int
1147 {
1152 else
1154 }
1156 /* If two types share a common base type, return that basetype.
1157 If there is not a unique most-derived base type, this function
1158 returns ERROR_MARK_NODE. */
1160 static tree
1162 {
1166 /* If one is a baseclass of another, that's good enough. */
1172 /* Otherwise, try to find a unique baseclass of TT1
1173 that is shared by TT2, and follow that down. */
1175 {
1180 {
1187 }
1188 }
1190 /* Same for TT2. */
1192 {
1197 {
1204 }
1205 }
1207 }
1208 \f
1209 /* Subroutines of `comptypes'. */
1211 /* Return true if two parameter type lists PARMS1 and PARMS2 are
1212 equivalent in the sense that functions with those parameter types
1213 can have equivalent types. The two lists must be equivalent,
1214 element by element. */
1216 bool
1218 {
1221 /* An unspecified parmlist matches any specified parmlist
1222 whose argument types don't need default promotions. */
1227 {
1228 /* If one parmlist is shorter than the other,
1229 they fail to match. */
1234 }
1236 }
1238 \f
1239 /* Process a sizeof or alignof expression where the operand is a
1240 type. */
1242 tree
1244 {
1245 tree value;
1254 {
1259 }
1265 /* VLA types will have a non-constant size. In the body of an
1266 uninstantiated template, we don't need to try to compute the
1267 value, because the sizeof expression is not an integral
1268 constant expression in that case. And, if we do try to
1269 compute the value, we'll likely end up with SAVE_EXPRs, which
1270 the template substitution machinery does not expect to see. */
1271 || (processing_template_decl
1274 {
1278 }
1282 complain);
1283 }
1285 /* Process a sizeof expression where the operand is an expression. */
1287 static tree
1289 {
1294 {
1300 }
1305 {
1308 }
1310 {
1314 }
1316 {
1319 }
1320 else
1324 }
1326 /* Implement the __alignof keyword: Return the minimum required
1327 alignment of E, measured in bytes. For VAR_DECL's and
1328 FIELD_DECL's return DECL_ALIGN (which can be set from an
1329 "aligned" __attribute__ specification). */
1331 static tree
1333 {
1334 tree t;
1340 {
1346 }
1353 {
1356 }
1361 {
1365 }
1367 {
1370 }
1371 else
1375 }
1377 /* Process a sizeof or alignof expression E with code OP where the operand
1378 is an expression. */
1380 tree
1382 {
1385 else
1387 }
1388 \f
1389 /* EXPR is being used in a context that is not a function call.
1390 Enforce:
1392 [expr.ref]
1394 The expression can be used only as the left-hand operand of a
1395 member function call.
1397 [expr.mptr.operator]
1399 If the result of .* or ->* is a function, then that result can be
1400 used only as the operand for the function call operator ().
1402 by issuing an error message if appropriate. Returns true iff EXPR
1403 violates these rules. */
1405 bool
1407 {
1409 {
1412 }
1414 }
1416 /* If EXP is a reference to a bitfield, and the type of EXP does not
1417 match the declared type of the bitfield, return the declared type
1418 of the bitfield. Otherwise, return NULL_TREE. */
1420 tree
1422 {
1423 tree field;
1426 {
1430 }
1440 }
1442 /* Perform the conversions in [expr] that apply when an lvalue appears
1443 in an rvalue context: the lvalue-to-rvalue, array-to-pointer, and
1444 function-to-pointer conversions. In addition, manifest constants
1445 are replaced by their values, and bitfield references are converted
1446 to their declared types.
1448 Although the returned value is being used as an rvalue, this
1449 function does not wrap the returned expression in a
1450 NON_LVALUE_EXPR; the caller is expected to be mindful of the fact
1451 that the return value is no longer an lvalue. */
1453 tree
1455 {
1456 tree type;
1464 {
1467 }
1473 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
1474 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */
1477 {
1480 }
1486 {
1487 tree adr;
1488 tree ptrtype;
1495 {
1499 }
1503 {
1506 }
1511 {
1516 }
1517 /* This way is better for a COMPONENT_REF since it can
1518 simplify the offset for a component. */
1521 }
1523 /* If a bitfield is used in a context where integral promotion
1524 applies, then the caller is expected to have used
1525 default_conversion. That function promotes bitfields correctly
1526 before calling this function. At this point, if we have a
1527 bitfield referenced, we may assume that is not subject to
1528 promotion, and that, therefore, the type of the resulting rvalue
1529 is the declared type of the bitfield. */
1532 /* We do not call rvalue() here because we do not want to wrap EXP
1533 in a NON_LVALUE_EXPR. */
1535 /* [basic.lval]
1537 Non-class rvalues always have cv-unqualified types. */
1543 }
1545 /* Perform prepatory conversions, as part of the "usual arithmetic
1546 conversions". In particular, as per [expr]:
1548 Whenever an lvalue expression appears as an operand of an
1549 operator that expects the rvalue for that operand, the
1550 lvalue-to-rvalue, array-to-pointer, or function-to-pointer
1551 standard conversions are applied to convert the expression to an
1552 rvalue.
1554 In addition, we perform integral promotions here, as those are
1555 applied to both operands to a binary operator before determining
1556 what additional conversions should apply. */
1558 tree
1560 {
1561 /* Perform the integral promotions first so that bitfield
1562 expressions (which may promote to "int", even if the bitfield is
1563 declared "unsigned") are promoted correctly. */
1566 /* Perform the other conversions. */
1570 }
1572 /* EXPR is an expression with an integral or enumeration type.
1573 Perform the integral promotions in [conv.prom], and return the
1574 converted value. */
1576 tree
1578 {
1579 tree type;
1580 tree promoted_type;
1582 /* [conv.prom]
1584 If the bitfield has an enumerated type, it is treated as any
1585 other value of that type for promotion purposes. */
1594 }
1596 /* Take the address of an inline function without setting TREE_ADDRESSABLE
1597 or TREE_USED. */
1599 tree
1601 {
1606 }
1608 /* Returns nonzero iff exp is a STRING_CST or the result of applying
1609 decay_conversion to one. */
1611 int
1613 {
1614 tree t;
1625 {
1626 /* Make sure that we don't try to convert between char and wchar_t. */
1629 }
1630 else
1631 {
1632 /* Is this a string constant which has decayed to 'const char *'? */
1640 }
1642 /* This warning is not very useful, as it complains about printf. */
1646 totype);
1649 }
1651 /* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we
1652 can, for example, use as an lvalue. This code used to be in
1653 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c'
1654 expressions, where we're dealing with aggregates. But now it's again only
1655 called from unary_complex_lvalue. The case (in particular) that led to
1656 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd
1657 get it there. */
1659 static tree
1661 {
1662 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that
1663 the first operand is always the one to be used if both operands
1664 are equal, so we know what conditional expression this used to be. */
1666 {
1667 /* The following code is incorrect if either operand side-effects. */
1670 return
1678 }
1680 return
1684 }
1686 /* Given the TYPE of an anonymous union field inside T, return the
1687 FIELD_DECL for the field. If not found return NULL_TREE. Because
1688 anonymous unions can nest, we must also search all anonymous unions
1689 that are directly reachable. */
1691 tree
1693 {
1694 tree field;
1697 {
1703 /* If we find it directly, return the field. */
1706 {
1708 }
1710 /* Otherwise, it could be nested, search harder. */
1713 {
1717 }
1718 }
1720 }
1722 /* Build an expression representing OBJECT.MEMBER. OBJECT is an
1723 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is
1724 non-NULL, it indicates the path to the base used to name MEMBER.
1725 If PRESERVE_REFERENCE is true, the expression returned will have
1726 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression
1727 returned will have the type referred to by the reference.
1729 This function does not perform access control; that is either done
1730 earlier by the parser when the name of MEMBER is resolved to MEMBER
1731 itself, or later when overload resolution selects one of the
1732 functions indicated by MEMBER. */
1734 tree
1737 {
1738 tree object_type;
1739 tree member_scope;
1747 /* [expr.ref]
1749 The type of the first expression shall be "class object" (of a
1750 complete type). */
1756 {
1760 }
1762 /* The standard does not seem to actually say that MEMBER must be a
1763 member of OBJECT_TYPE. However, that is clearly what is
1764 intended. */
1766 {
1771 }
1772 else
1774 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will
1775 presently be the anonymous union. Go outwards until we find a
1776 type related to OBJECT_TYPE. */
1779 object_type))
1782 {
1785 else
1788 }
1790 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into
1791 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue
1792 in the frontend; only _DECLs and _REFs are lvalues in the backend. */
1793 {
1797 }
1799 /* In [expr.ref], there is an explicit list of the valid choices for
1800 MEMBER. We check for each of those cases here. */
1802 {
1803 /* A static data member. */
1805 /* If OBJECT has side-effects, they are supposed to occur. */
1808 }
1810 {
1811 /* A non-static data member. */
1814 tree member_type;
1819 /* Convert OBJECT to the type of MEMBER. */
1822 {
1823 tree binfo;
1824 base_kind kind;
1831 /* It is invalid to try to get to a virtual base of a
1832 NULL object. The most common cause is invalid use of
1833 offsetof macro. */
1835 {
1838 member);
1841 }
1843 /* Convert to the base. */
1846 /* If we found the base successfully then we should be able
1847 to convert to it successfully. */
1849 }
1851 /* Complain about other invalid uses of offsetof, even though they will
1852 give the right answer. Note that we complain whether or not they
1853 actually used the offsetof macro, since there's no way to know at this
1854 point. So we just give a warning, instead of a pedwarn. */
1855 /* Do not produce this warning for base class field references, because
1856 we know for a fact that didn't come from offsetof. This does occur
1857 in various testsuite cases where a null object is passed where a
1858 vtable access is required. */
1863 {
1865 member);
1867 }
1869 /* If MEMBER is from an anonymous aggregate, we have converted
1870 OBJECT so that it refers to the class containing the
1871 anonymous union. Generate a reference to the anonymous union
1872 itself, and recur to find MEMBER. */
1874 /* When this code is called from build_field_call, the
1875 object already has the type of the anonymous union.
1876 That is because the COMPONENT_REF was already
1877 constructed, and was then disassembled before calling
1878 build_field_call. After the function-call code is
1879 cleaned up, this waste can be eliminated. */
1880 && (!same_type_ignoring_top_level_qualifiers_p
1882 {
1883 tree anonymous_union;
1888 anonymous_union,
1890 preserve_reference);
1891 }
1893 /* Compute the type of the field, as described in [expr.ref]. */
1897 {
1901 /* A field is const (volatile) if the enclosing object, or the
1902 field itself, is const (volatile). But, a mutable field is
1903 not const, even within a const object. */
1907 }
1910 NULL_TREE);
1913 /* Mark the expression const or volatile, as appropriate. Even
1914 though we've dealt with the type above, we still have to mark the
1915 expression itself. */
1920 }
1922 {
1923 /* The member is a (possibly overloaded) member function. */
1924 tree functions;
1925 tree type;
1927 /* If the MEMBER is exactly one static member function, then we
1928 know the type of the expression. Otherwise, we must wait
1929 until overload resolution has been performed. */
1934 else
1936 /* Note that we do not convert OBJECT to the BASELINK_BINFO
1937 base. That will happen when the function is called. */
1939 }
1941 {
1942 /* The member is an enumerator. */
1944 /* If OBJECT has side-effects, they are supposed to occur. */
1948 }
1949 else
1950 {
1953 }
1956 /* [expr.ref]
1958 If E2 is declared to have type "reference to T", then ... the
1959 type of E1.E2 is T. */
1963 }
1965 /* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if
1966 SCOPE is NULL, by OBJECT.~DTOR_NAME. */
1968 static tree
1970 {
1973 tree expr;
1976 {
1980 }
1982 {
1986 }
1989 expr = (adjust_result_of_qualified_name_lookup
1992 }
1994 /* An expression of the form "A::template B" has been resolved to
1995 DECL. Issue a diagnostic if B is not a template or template
1996 specialization. */
1998 void
2000 {
2001 /* The standard says:
2003 [temp.names]
2005 If a name prefixed by the keyword template is not a member
2006 template, the program is ill-formed.
2008 DR 228 removed the restriction that the template be a member
2009 template.
2011 DR 96, if accepted would add the further restriction that explicit
2012 template arguments must be provided if the template keyword is
2013 used, but, as of 2005-10-16, that DR is still in "drafting". If
2014 this DR is accepted, then the semantic checks here can be
2015 simplified, as the entity named must in fact be a template
2016 specialization, rather than, as at present, a set of overloaded
2017 functions containing at least one template function. */
2020 {
2023 else
2024 {
2025 tree fns;
2030 {
2040 }
2043 }
2044 }
2045 }
2047 /* This function is called by the parser to process a class member
2048 access expression of the form OBJECT.NAME. NAME is a node used by
2049 the parser to represent a name; it is not yet a DECL. It may,
2050 however, be a BASELINK where the BASELINK_FUNCTIONS is a
2051 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and
2052 there is no reason to do the lookup twice, so the parser keeps the
2053 BASELINK. TEMPLATE_P is true iff NAME was explicitly declared to
2054 be a template via the use of the "A::template B" syntax. */
2056 tree
2058 {
2059 tree expr;
2060 tree object_type;
2061 tree member;
2069 /* If OBJECT is an ObjC class instance, we must obey ObjC access rules. */
2076 {
2079 /* If NAME is just an IDENTIFIER_NODE, then the expression
2080 is dependent. */
2082 /* If NAME is "f<args>", where either 'f' or 'args' is
2083 dependent, then the expression is dependent. */
2087 /* If NAME is "T::X" where "T" is dependent, then the
2088 expression is dependent. */
2094 }
2096 /* [expr.ref]
2098 The type of the first expression shall be "class object" (of a
2099 complete type). */
2104 {
2108 }
2111 /* A member function that has already been looked up. */
2113 else
2114 {
2117 tree scope;
2120 {
2129 }
2132 {
2133 /* A qualified name. The qualifying class or namespace `S'
2134 has already been looked up; it is either a TYPE or a
2135 NAMESPACE_DECL. */
2139 /* If SCOPE is a namespace, then the qualified name does not
2140 name a member of OBJECT_TYPE. */
2142 {
2146 }
2152 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */
2157 {
2160 }
2161 }
2162 else
2163 {
2166 }
2170 else
2171 {
2172 /* Look up the member. */
2176 {
2179 }
2182 }
2185 {
2190 else
2191 {
2194 }
2195 }
2196 }
2207 {
2209 {
2213 }
2216 NULL_TREE);
2217 }
2220 }
2222 /* Return an expression for the MEMBER_NAME field in the internal
2223 representation of PTRMEM, a pointer-to-member function. (Each
2224 pointer-to-member function type gets its own RECORD_TYPE so it is
2225 more convenient to access the fields by name than by FIELD_DECL.)
2226 This routine converts the NAME to a FIELD_DECL and then creates the
2227 node for the complete expression. */
2229 tree
2231 {
2232 tree ptrmem_type;
2233 tree member;
2234 tree member_type;
2236 /* This code is a stripped down version of
2237 build_class_member_access_expr. It does not work to use that
2238 routine directly because it expects the object to be of class
2239 type. */
2248 }
2250 /* Given an expression PTR for a pointer, return an expression
2251 for the value pointed to.
2252 ERRORSTRING is the name of the operator to appear in error messages.
2254 This function may need to overload OPERATOR_FNNAME.
2255 Must also handle REFERENCE_TYPEs for C++. */
2257 tree
2259 {
2261 tree rval;
2264 {
2268 }
2277 else
2279 }
2281 tree
2283 {
2297 {
2298 /* [expr.unary.op]
2300 If the type of the expression is "pointer to T," the type
2301 of the result is "T."
2303 We must use the canonical variant because certain parts of
2304 the back end, like fold, do pointer comparisons between
2305 types. */
2309 {
2310 /* A pointer to incomplete type (other than cv void) can be
2311 dereferenced [expr.unary.op]/1 */
2314 }
2317 /* The POINTER was something like `&x'. We simplify `*&x' to
2318 `x'. */
2320 else
2321 {
2324 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2325 so that we get the proper error message if the result is used
2326 to assign to. Also, &* is supposed to be a no-op. */
2332 }
2333 }
2334 /* `pointer' won't be an error_mark_node if we were given a
2335 pointer to member, so it's cool to check for this here. */
2339 {
2342 else
2344 }
2346 }
2348 /* This handles expressions of the form "a[i]", which denotes
2349 an array reference.
2351 This is logically equivalent in C to *(a+i), but we may do it differently.
2352 If A is a variable or a member, we generate a primitive ARRAY_REF.
2353 This avoids forcing the array out of registers, and can work on
2354 arrays that are not lvalues (for example, members of structures returned
2355 by functions).
2357 If INDEX is of some user-defined type, it must be converted to
2358 integer type. Otherwise, to make a compatible PLUS_EXPR, it
2359 will inherit the type of the array, which will be some pointer type. */
2361 tree
2363 {
2365 {
2368 }
2374 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference
2375 inside it. */
2377 {
2379 {
2383 }
2386 return build_conditional_expr
2393 }
2396 {
2402 {
2405 }
2407 /* Apply integral promotions *after* noticing character types.
2408 (It is unclear why we do these promotions -- the standard
2409 does not say that we should. In fact, the natural thing would
2410 seem to be to convert IDX to ptrdiff_t; we're performing
2411 pointer arithmetic.) */
2414 /* An array that is indexed by a non-constant
2415 cannot be stored in a register; we must be able to do
2416 address arithmetic on its address.
2417 Likewise an array of elements of variable size. */
2422 {
2425 }
2427 /* An array that is indexed by a constant value which is not within
2428 the array bounds cannot be stored in a register either; because we
2429 would get a crash in store_bit_field/extract_bit_field when trying
2430 to access a non-existent part of the register. */
2434 {
2437 }
2442 /* Note in C++ it is valid to subscript a `register' array, since
2443 it is valid to take the address of something with that
2444 storage specification. */
2446 {
2452 }
2456 /* Array ref is const/volatile if the array elements are
2457 or if the array is.. */
2465 }
2467 {
2471 /* Put the integer in IND to simplify error checking. */
2473 {
2477 }
2483 {
2486 }
2488 {
2491 }
2497 }
2498 }
2499 \f
2500 /* Resolve a pointer to member function. INSTANCE is the object
2501 instance to use, if the member points to a virtual member.
2503 This used to avoid checking for virtual functions if basetype
2504 has no virtual functions, according to an earlier ANSI draft.
2505 With the final ISO C++ rules, such an optimization is
2506 incorrect: A pointer to a derived member can be static_cast
2507 to pointer-to-base-member, as long as the dynamic object
2508 later has the right member. */
2510 tree
2512 {
2517 {
2524 {
2526 {
2527 /* Extracting the function address from a pmf is only
2528 allowed with -Wno-pmf-conversions. It only works for
2529 pmf constants. */
2533 }
2534 else
2535 {
2538 }
2539 }
2547 /* Start by extracting all the information from the PMF itself. */
2552 {
2565 }
2567 /* Convert down to the right base before using the instance. A
2568 special case is that in a pointer to member of class C, C may
2569 be incomplete. In that case, the function will of course be
2570 a member of C, and no conversion is required. In fact,
2571 lookup_base will fail in that case, because incomplete
2572 classes do not have BINFOs. */
2576 {
2583 }
2584 /* ...and then the delta in the PMF. */
2588 /* Hand back the adjusted 'this' argument to our caller. */
2591 /* Next extract the vtable pointer from the object. */
2593 instance_ptr);
2596 /* Finally, extract the function pointer from the vtable. */
2602 /* When using function descriptors, the address of the
2603 vtable entry is treated as a function pointer. */
2611 /* Make sure this doesn't get evaluated first inside one of the
2612 branches of the COND_EXPR. */
2618 }
2620 }
2622 tree
2624 {
2626 tree coerced_params;
2631 /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2632 expressions, like those used for ObjC messenger dispatches. */
2635 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2636 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */
2642 {
2648 /* Convert anything with function type to a pointer-to-function. */
2652 /* Differs from default_conversion by not setting TREE_ADDRESSABLE
2653 (because calling an inline function does not mean the function
2654 needs to be separately compiled). */
2658 else
2660 }
2661 else
2662 {
2666 }
2674 {
2677 original);
2679 }
2686 || is_method
2688 {
2691 }
2693 /* fntype now gets the type of function pointed to. */
2696 /* Convert the parameters to the types declared in the
2697 function prototype, or apply default promotions. */
2704 /* Check for errors in format strings and inappropriately
2705 null parameters. */
2711 }
2712 \f
2713 /* Convert the actual parameter expressions in the list VALUES
2714 to the types in the list TYPELIST.
2715 If parmdecls is exhausted, or when an element has NULL as its type,
2716 perform the default conversions.
2718 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages.
2720 This is also where warnings about wrong number of args are generated.
2722 Return a list of expressions for the parameters as converted.
2724 Both VALUES and the returned value are chains of TREE_LIST nodes
2725 with the elements of the list in the TREE_VALUE slots of those nodes.
2727 In C++, unspecified trailing parameters can be filled in with their
2728 default arguments, if such were specified. Do so here. */
2730 static tree
2732 {
2738 /* Argument passing is always copy-initialization. */
2742 {
2744 {
2748 else
2750 }
2751 else
2753 }
2756 valtail;
2758 {
2766 {
2768 {
2771 }
2772 else
2774 /* In case anybody wants to know if this argument
2775 list is valid. */
2779 }
2781 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2782 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */
2789 {
2794 }
2800 {
2801 /* Formal parm type is specified by a function prototype. */
2802 tree parmval;
2805 {
2809 else
2812 }
2813 else
2814 {
2815 parmval = convert_for_initialization
2819 }
2825 }
2826 else
2827 {
2830 /* Don't do ellipsis conversion for __built_in_constant_p
2831 as this will result in spurious warnings for non-POD
2832 types. */
2834 else
2838 }
2842 }
2845 {
2846 /* See if there are default arguments that can be used. */
2849 {
2851 {
2852 tree parmval
2862 /* ends with `...'. */
2865 }
2866 }
2867 else
2868 {
2870 {
2873 }
2874 else
2877 }
2878 }
2881 }
2882 \f
2883 /* Build a binary-operation expression, after performing default
2884 conversions on the operands. CODE is the kind of expression to build. */
2886 tree
2889 {
2890 tree orig_arg1;
2891 tree orig_arg2;
2892 tree expr;
2898 {
2904 }
2908 else
2910 overloaded_p);
2916 }
2918 /* Build a binary-operation expression without default conversions.
2919 CODE is the kind of expression to build.
2920 This function differs from `build' in several ways:
2921 the data type of the result is computed and recorded in it,
2922 warnings are generated if arg data types are invalid,
2923 special handling for addition and subtraction of pointers is known,
2924 and some optimization is done (operations on narrow ints
2925 are done in the narrower type when that gives the same result).
2926 Constant folding is also done before the result is returned.
2928 Note that the operands will never have enumeral types
2929 because either they have just had the default conversions performed
2930 or they have both just been converted to some other type in which
2931 the arithmetic is to be done.
2933 C++: must do special pointer arithmetic when implementing
2934 multiple inheritance, and deal with pointer to member functions. */
2936 tree
2939 {
2945 /* Expression code to give to the expression when it is built.
2946 Normally this is CODE, which is what the caller asked for,
2947 but in some special cases we change it. */
2950 /* Data type in which the computation is to be performed.
2951 In the simplest cases this is the common type of the arguments. */
2954 /* Nonzero means operands have already been type-converted
2955 in whatever way is necessary.
2956 Zero means they need to be converted to RESULT_TYPE. */
2959 /* Nonzero means create the expression with this type, rather than
2960 RESULT_TYPE. */
2963 /* Nonzero means after finally constructing the expression
2964 convert it to this type. */
2967 tree result;
2969 /* Nonzero if this is an operation like MIN or MAX which can
2970 safely be computed in short if both args are promoted shorts.
2971 Also implies COMMON.
2972 -1 indicates a bitwise operation; this makes a difference
2973 in the exact conditions for when it is safe to do the operation
2974 in a narrower mode. */
2977 /* Nonzero if this is a comparison operation;
2978 if both args are promoted shorts, compare the original shorts.
2979 Also implies COMMON. */
2982 /* Nonzero if this is a right-shift operation, which can be computed on the
2983 original short and then promoted if the operand is a promoted short. */
2986 /* Nonzero means set RESULT_TYPE to the common type of the args. */
2989 /* True if both operands have arithmetic type. */
2992 /* Apply default conversions. */
2999 {
3004 }
3005 else
3006 {
3011 }
3013 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
3017 /* DTRT if one side is an overloaded function, but complain about it. */
3019 {
3022 {
3026 }
3027 }
3029 {
3032 {
3036 }
3037 }
3042 /* The expression codes of the data types of the arguments tell us
3043 whether the arguments are integers, floating, pointers, etc. */
3047 /* If an error was already reported for one of the arguments,
3048 avoid reporting another error. */
3055 {
3058 }
3061 {
3063 /* Subtraction of two similar pointers.
3064 We must subtract them as integers, then divide by object size. */
3069 /* In all other cases except pointer - int, the usual arithmetic
3070 rules aply. */
3072 {
3075 }
3076 /* The pointer - int case is just like pointer + int; fall
3077 through. */
3081 {
3082 tree ptr_operand;
3083 tree int_operand;
3087 {
3090 }
3092 ptr_operand,
3093 int_operand);
3094 }
3111 {
3124 else
3125 /* When dividing two signed integers, we have to promote to int.
3126 unless we divide by a constant != -1. Note that default
3127 conversion will have been performed on the operands at this
3128 point, so we have to dig out the original type to find out if
3129 it was unsigned. */
3136 }
3155 {
3156 /* Although it would be tempting to shorten always here, that loses
3157 on some targets, since the modulo instruction is undefined if the
3158 quotient can't be represented in the computation mode. We shorten
3159 only if unsigned or if dividing by something we know != -1. */
3165 }
3175 /* Shift operations: result has same type as first operand;
3176 always convert second operand to int.
3177 Also set SHORT_SHIFT if shifting rightward. */
3181 {
3184 {
3187 else
3188 {
3193 }
3194 }
3195 /* Convert the shift-count to an integer, regardless of
3196 size of value being shifted. */
3199 /* Avoid converting op1 to result_type later. */
3201 }
3206 {
3209 {
3214 }
3215 /* Convert the shift-count to an integer, regardless of
3216 size of value being shifted. */
3219 /* Avoid converting op1 to result_type later. */
3221 }
3227 {
3230 {
3239 }
3240 /* Convert the shift-count to an integer, regardless of
3241 size of value being shifted. */
3244 }
3274 {
3277 }
3279 {
3282 }
3284 {
3288 }
3293 {
3294 /* E will be the final comparison. */
3295 tree e;
3296 /* E1 and E2 are for scratch. */
3297 tree e1;
3298 tree e2;
3299 tree pfn0;
3300 tree pfn1;
3301 tree delta0;
3302 tree delta1;
3309 /* We generate:
3311 (op0.pfn == op1.pfn
3312 && (!op0.pfn || op0.delta == op1.delta))
3314 The reason for the `!op0.pfn' bit is that a NULL
3315 pointer-to-member is any member with a zero PFN; the
3316 DELTA field is unspecified. */
3320 delta_identifier);
3322 delta_identifier);
3325 pfn0,
3327 integer_zero_node));
3334 }
3335 else
3336 {
3339 type1));
3342 type0));
3343 }
3380 {
3383 }
3385 {
3388 }
3400 {
3403 }
3409 }
3415 else
3416 {
3418 /* Vector arithmetic is only allowed when both sides are vectors. */
3420 {
3424 {
3427 }
3429 }
3430 }
3431 /* Determine the RESULT_TYPE, if it is not already known. */
3433 && arithmetic_types_p
3438 {
3442 }
3444 /* If we're in a template, the only thing we need to know is the
3445 RESULT_TYPE. */
3452 {
3455 /* For certain operations (which identify themselves by shorten != 0)
3456 if both args were extended from the same smaller type,
3457 do the arithmetic in that type and then extend.
3459 shorten !=0 and !=1 indicates a bitwise operation.
3460 For them, this optimization is safe only if
3461 both args are zero-extended or both are sign-extended.
3462 Otherwise, we might change the result.
3463 Eg, (short)-1 | (unsigned short)-1 is (int)-1
3464 but calculated in (unsigned short) it would be (unsigned short)-1. */
3467 {
3471 /* UNS is 1 if the operation to be done is an unsigned one. */
3473 tree type;
3477 /* Handle the case that OP0 does not *contain* a conversion
3478 but it *requires* conversion to FINAL_TYPE. */
3485 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */
3487 /* For bitwise operations, signedness of nominal type
3488 does not matter. Consider only how operands were extended. */
3492 /* Note that in all three cases below we refrain from optimizing
3493 an unsigned operation on sign-extended args.
3494 That would not be valid. */
3496 /* Both args variable: if both extended in same way
3497 from same width, do it in that width.
3498 Do it unsigned if args were zero-extended. */
3505 result_type = c_common_signed_or_unsigned_type
3523 }
3525 /* Shifts can be shortened if shifting right. */
3528 {
3538 /* We can shorten only if the shift count is less than the
3539 number of bits in the smaller type size. */
3541 /* If arg is sign-extended and then unsigned-shifted,
3542 we can simulate this with a signed shift in arg's type
3543 only if the extended result is at least twice as wide
3544 as the arg. Otherwise, the shift could use up all the
3545 ones made by sign-extension and bring in zeros.
3546 We can't optimize that case at all, but in most machines
3547 it never happens because available widths are 2**N. */
3549 || unsigned_arg
3552 {
3553 /* Do an unsigned shift if the operand was zero-extended. */
3554 result_type
3557 /* Convert value-to-be-shifted to that type. */
3561 }
3562 }
3564 /* Comparison operations are shortened too but differently.
3565 They identify themselves by setting short_compare = 1. */
3568 {
3569 /* Don't write &op0, etc., because that would prevent op0
3570 from being kept in a register.
3571 Instead, make copies of the our local variables and
3572 pass the copies by reference, then copy them back afterward. */
3575 tree val
3582 }
3585 && warn_sign_compare
3586 /* Do not warn until the template is instantiated; we cannot
3587 bound the ranges of the arguments until that point. */
3589 {
3597 /* Check for comparison of different enum types. */
3602 {
3605 }
3607 /* Give warnings for comparisons between signed and unsigned
3608 quantities that may fail. */
3609 /* Do the checking based on the original operand trees, so that
3610 casts will be considered, but default promotions won't be. */
3612 /* Do not warn if the comparison is being done in a signed type,
3613 since the signed type will only be chosen if it can represent
3614 all the values of the unsigned type. */
3617 /* Do not warn if both operands are unsigned. */
3620 /* Do not warn if the signed quantity is an unsuffixed
3621 integer literal (or some static constant expression
3622 involving such literals or a conditional expression
3623 involving such literals) and it is non-negative. */
3627 /* Do not warn if the comparison is an equality operation,
3628 the unsigned quantity is an integral constant and it does
3629 not use the most significant bit of result_type. */
3638 else
3641 /* Warn if two unsigned values are being compared in a size
3642 larger than their original size, and one (and only one) is the
3643 result of a `~' operator. This comparison will always fail.
3645 Also warn if one operand is a constant, and the constant does not
3646 have all bits set that are set in the ~ operand when it is
3647 extended. */
3651 {
3658 {
3659 tree primop;
3665 {
3669 }
3670 else
3671 {
3675 }
3680 {
3684 }
3685 }
3692 }
3693 }
3694 }
3696 /* If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
3697 Then the expression will be built.
3698 It will be given type FINAL_TYPE if that is nonzero;
3699 otherwise, it will be given type RESULT_TYPE. */
3701 /* Issue warnings about peculiar, but valid, uses of NULL. */
3703 and ||, so NULL is no exception. */
3708 /* Or vice versa. */
3711 /* Or, both are NULL and the operation was not a comparison. */
3714 /* Some sort of arithmetic operation involving NULL was
3715 performed. Note that pointer-difference and pointer-addition
3716 have already been handled above, and so we don't end up here in
3717 that case. */
3721 {
3729 }
3739 }
3740 \f
3741 /* Return a tree for the sum or difference (RESULTCODE says which)
3742 of pointer PTROP and integer INTOP. */
3744 static tree
3746 {
3749 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type)
3750 in certain circumstance (when it's valid to do so). So we need
3751 to make sure it's complete. We don't need to check here, if we
3752 can actually complete it at all, as those checks will be done in
3753 pointer_int_sum() anyway. */
3758 }
3760 /* Return a tree for the difference of pointers OP0 and OP1.
3761 The resulting tree has type int. */
3763 static tree
3765 {
3766 tree result;
3774 {
3781 }
3783 /* First do the subtraction as integers;
3784 then drop through to build the divide operator. */
3790 /* This generates an error if op1 is a pointer to an incomplete type. */
3798 /* Do the division. */
3802 }
3803 \f
3804 /* Construct and perhaps optimize a tree representation
3805 for a unary operation. CODE, a tree_code, specifies the operation
3806 and XARG is the operand. */
3808 tree
3810 {
3812 tree exp;
3816 {
3821 }
3825 /* [expr.unary.op] says:
3827 The address of an object of incomplete type can be taken.
3829 (And is just the ordinary address operator, not an overloaded
3830 "operator &".) However, if the type is a template
3831 specialization, we must complete the type at this point so that
3832 an overloaded "operator &" will be available if required. */
3839 else
3843 {
3844 /* A pointer to member-function can be formed only by saying
3845 &X::mf. */
3848 {
3851 {
3853 xarg);
3857 }
3858 else
3859 {
3862 xarg);
3864 }
3865 }
3868 {
3873 {
3874 /* A single non-static member, make sure we don't allow a
3875 pointer-to-member. */
3880 }
3881 }
3885 }
3893 }
3895 /* Like c_common_truthvalue_conversion, but handle pointer-to-member
3896 constants, where a null value is represented by an INTEGER_CST of
3897 -1. */
3899 tree
3901 {
3905 else
3907 }
3909 /* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */
3911 tree
3913 {
3914 tree t;
3920 }
3922 /* Return an ADDR_EXPR giving the address of T. This function
3923 attempts no optimizations or simplifications; it is a low-level
3924 primitive. */
3926 tree
3928 {
3929 tree addr;
3937 }
3939 /* Return a NOP_EXPR converting EXPR to TYPE. */
3941 tree
3943 {
3947 }
3949 /* C++: Must handle pointers to members.
3951 Perhaps type instantiation should be extended to handle conversion
3952 from aggregates to types we don't yet know we want? (Or are those
3953 cases typically errors which should be reported?)
3955 NOCONVERT nonzero suppresses the default promotions
3956 (such as from short to int). */
3958 tree
3960 {
3961 /* No default_conversion here. It causes trouble for ADDR_EXPR. */
3965 tree val;
3973 ? CONVERT_EXPR
3976 {
3979 }
3982 {
3985 {
3987 /* Unary plus (but not unary minus) is allowed on pointers. */
3995 else
3996 {
4000 /* Make sure the result is not an lvalue: a unary plus or minus
4001 expression is always a rvalue. */
4003 }
4004 }
4009 {
4013 }
4029 /* Conjugating a real value is a no-op, but allow it anyway. */
4051 {
4054 }
4055 else
4062 {
4065 }
4066 else
4073 /* Handle complex lvalues (when permitted)
4074 by reduction to simpler cases. */
4080 /* Increment or decrement the real part of the value,
4081 and don't change the imaginary part. */
4083 {
4091 }
4093 /* Report invalid types. */
4097 {
4104 else
4107 }
4109 /* Report something read-only. */
4118 {
4119 tree inc;
4125 /* ARM $5.2.5 last annotation says this should be forbidden. */
4131 /* Compute the increment. */
4134 {
4149 argtype);
4151 }
4152 else
4157 /* Handle incrementing a cast-expression. */
4160 {
4168 {
4175 else
4186 /* Eliminate warning about unused result of + or -. */
4189 }
4193 }
4195 /* Complain about anything else that is not a true lvalue. */
4201 /* Forbid using -- on `bool'. */
4203 {
4205 {
4208 }
4210 }
4211 else
4216 }
4219 /* Note that this operation never does default_conversion
4220 regardless of NOCONVERT. */
4228 {
4232 }
4234 /* ARM $3.4 */
4237 /* Let &* cancel out to simplify resulting code. */
4239 {
4240 /* We don't need to have `current_class_ptr' wrapped in a
4241 NON_LVALUE_EXPR node. */
4247 {
4250 }
4251 else
4252 /* Don't let this be an lvalue. */
4255 }
4257 /* Uninstantiated types are all functions. Taking the
4258 address of a function is a no-op, so just return the
4259 argument. */
4266 {
4267 /* They're trying to take the address of a unique non-static
4268 member function. This is ill-formed (except in MS-land),
4269 but let's try to DTRT.
4270 Note: We only handle unique functions here because we don't
4271 want to complain if there's a static overload; non-unique
4272 cases will be handled by instantiate_type. But we need to
4273 handle this case here to allow casts on the resulting PMF.
4274 We could defer this in non-MS mode, but it's easier to give
4275 a useful error here. */
4277 /* Inside constant member functions, the `this' pointer
4278 contains an extra const qualifier. TYPE_MAIN_VARIANT
4279 is used here to remove this const from the diagnostics
4280 and the created OFFSET_REF. */
4286 {
4290 /* An expression like &memfn. */
4292 " or parenthesized non-static member function to form"
4295 else
4297 " function to form a pointer to member function."
4300 }
4302 }
4304 offset_ref:
4308 /* Handle complex lvalues (when permitted)
4309 by reduction to simpler cases. */
4315 {
4329 /* Fall through. */
4336 /* Turn a reference to a non-static data member into a
4337 pointer-to-member. */
4338 {
4339 tree type;
4340 tree t;
4347 {
4350 }
4356 }
4360 }
4362 /* Anything not already handled and not a true memory reference
4363 is an error. */
4373 /* In a template, we are processing a non-dependent expression
4374 so we can just form an ADDR_EXPR with the correct type. */
4376 {
4381 }
4384 {
4388 }
4390 {
4393 /* We can only get here with a single static member
4394 function. */
4400 /* Do not lose object's side effects. */
4403 }
4405 {
4409 }
4410 else
4411 {
4417 }
4421 {
4425 }
4431 }
4434 {
4438 }
4442 }
4444 /* Apply unary lvalue-demanding operator CODE to the expression ARG
4445 for certain kinds of expressions which are not really lvalues
4446 but which we can accept as lvalues.
4448 If ARG is not a kind of expression we can handle, return
4449 NULL_TREE. */
4451 tree
4453 {
4454 /* Inside a template, making these kinds of adjustments is
4455 pointless; we are only concerned with the type of the
4456 expression. */
4460 /* Handle (a, b) used as an "lvalue". */
4462 {
4466 }
4468 /* Handle (a ? b : c) used as an "lvalue". */
4473 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */
4477 {
4480 {
4484 }
4485 return unary_complex_lvalue
4487 }
4492 /* Handle (a = b) used as an "lvalue" for `&'. */
4495 {
4501 }
4508 /* We permit compiler to make function calls returning
4509 objects of aggregate type look like lvalues. */
4510 {
4517 {
4520 else
4523 }
4528 }
4530 /* Don't let anything else be handled specially. */
4532 }
4533 \f
4534 /* Mark EXP saying that we need to be able to take the
4535 address of it; it should not be allocated in a register.
4536 Value is true if successful.
4538 C++: we do not allow `current_class_ptr' to be addressable. */
4540 bool
4542 {
4547 {
4558 {
4562 }
4563 /* Fall through. */
4566 /* Caller should not be trying to mark initialized
4567 constant fields addressable. */
4572 /* Fall through. */
4578 {
4580 {
4581 error
4584 }
4586 warning
4588 }
4607 }
4608 }
4609 \f
4610 /* Build and return a conditional expression IFEXP ? OP1 : OP2. */
4612 tree
4614 {
4618 tree expr;
4621 {
4622 /* The standard says that the expression is type-dependent if
4623 IFEXP is type-dependent, even though the eventual type of the
4624 expression doesn't dependent on IFEXP. */
4626 /* As a GNU extension, the middle operand may be omitted. */
4634 }
4641 }
4642 \f
4643 /* Given a list of expressions, return a compound expression
4644 that performs them all and returns the value of the last of them. */
4647 {
4651 {
4657 }
4660 }
4662 /* Handle overloading of the ',' operator when needed. */
4664 tree
4666 {
4667 tree result;
4672 {
4678 }
4689 }
4691 /* Build a compound expression. */
4693 tree
4695 {
4702 {
4703 /* If the rhs is a TARGET_EXPR, then build the compound
4704 expression inside the target_expr's initializer. This
4705 helps the compiler to eliminate unnecessary temporaries. */
4712 }
4715 }
4717 /* Issue a diagnostic message if casting from SRC_TYPE to DEST_TYPE
4718 casts away constness. DIAG_FN gives the function to call if we
4719 need to issue a diagnostic; if it is NULL, no diagnostic will be
4720 issued. DESCRIPTION explains what operation is taking place. */
4722 static void
4726 {
4730 }
4732 /* Convert EXPR (an expression with pointer-to-member type) to TYPE
4733 (another pointer-to-member type in the same hierarchy) and return
4734 the converted expression. If ALLOW_INVERSE_P is permitted, a
4735 pointer-to-derived may be converted to pointer-to-base; otherwise,
4736 only the other direction is permitted. If C_CAST_P is true, this
4737 conversion is taking place as part of a C-style cast. */
4739 tree
4742 {
4744 {
4745 tree delta;
4751 allow_inverse_p,
4752 c_cast_p);
4756 delta);
4758 }
4759 else
4762 }
4764 /* If EXPR is an INTEGER_CST and ORIG is an arithmetic constant, return
4765 a version of EXPR that has TREE_OVERFLOW and/or TREE_CONSTANT_OVERFLOW
4766 set iff they are set in ORIG. Otherwise, return EXPR unchanged. */
4768 static tree
4770 {
4777 {
4779 /* Ensure constant sharing. */
4783 else
4784 {
4785 /* Avoid clobbering a shared constant. */
4790 }
4791 }
4793 }
4795 /* Perform a static_cast from EXPR to TYPE. When C_CAST_P is true,
4796 this static_cast is being attempted as one of the possible casts
4797 allowed by a C-style cast. (In that case, accessibility of base
4798 classes is not considered, and it is OK to cast away
4799 constness.) Return the result of the cast. *VALID_P is set to
4800 indicate whether or not the cast was valid. */
4802 static tree
4805 {
4806 tree intype;
4807 tree result;
4808 tree orig;
4812 /* Assume the cast is valid. */
4817 /* Save casted types in the function's used types hash table. */
4820 /* Determine what to do when casting away constness. */
4822 {
4823 /* C-style casts are allowed to cast away constness. With
4824 WARN_CAST_QUAL, we still want to issue a warning. */
4827 }
4828 else
4829 {
4830 /* A static_cast may not cast away constness. */
4833 }
4835 /* [expr.static.cast]
4837 An lvalue of type "cv1 B", where B is a class type, can be cast
4838 to type "reference to cv2 D", where D is a class derived (clause
4839 _class.derived_) from B, if a valid standard conversion from
4840 "pointer to D" to "pointer to B" exists (_conv.ptr_), cv2 is the
4841 same cv-qualification as, or greater cv-qualification than, cv1,
4842 and B is not a virtual base class of D. */
4843 /* We check this case before checking the validity of "TYPE t =
4844 EXPR;" below because for this case:
4846 struct B {};
4847 struct D : public B { D(const B&); };
4848 extern B& b;
4849 void f() { static_cast<const D&>(b); }
4851 we want to avoid constructing a new D. The standard is not
4852 completely clear about this issue, but our interpretation is
4853 consistent with other compilers. */
4862 && (c_cast_p
4864 {
4865 tree base;
4867 /* There is a standard conversion from "D*" to "B*" even if "B"
4868 is ambiguous or inaccessible. If this is really a
4869 static_cast, then we check both for inaccessibility and
4870 ambiguity. However, if this is a static_cast being performed
4871 because the user wrote a C-style cast, then accessibility is
4872 not considered. */
4875 NULL);
4877 /* Convert from "B*" to "D*". This function will check that "B"
4878 is not a virtual base of "D". */
4881 /* Convert the pointer to a reference -- but then remember that
4882 there are no expressions with reference type in C++. */
4884 }
4888 /* [expr.static.cast]
4890 An expression e can be explicitly converted to a type T using a
4891 static_cast of the form static_cast<T>(e) if the declaration T
4892 t(e);" is well-formed, for some invented temporary variable
4893 t. */
4895 c_cast_p);
4897 {
4900 /* Ignore any integer overflow caused by the cast. */
4903 /* [expr.static.cast]
4905 If T is a reference type, the result is an lvalue; otherwise,
4906 the result is an rvalue. */
4910 }
4912 /* [expr.static.cast]
4914 Any expression can be explicitly converted to type cv void. */
4918 /* [expr.static.cast]
4920 The inverse of any standard conversion sequence (clause _conv_),
4921 other than the lvalue-to-rvalue (_conv.lval_), array-to-pointer
4922 (_conv.array_), function-to-pointer (_conv.func_), and boolean
4923 (_conv.bool_) conversions, can be performed explicitly using
4924 static_cast subject to the restriction that the explicit
4925 conversion does not cast away constness (_expr.const.cast_), and
4926 the following additional rules for specific cases: */
4927 /* For reference, the conversions not excluded are: integral
4928 promotions, floating point promotion, integral conversions,
4929 floating point conversions, floating-integral conversions,
4930 pointer conversions, and pointer to member conversions. */
4931 /* DR 128
4933 A value of integral _or enumeration_ type can be explicitly
4934 converted to an enumeration type. */
4935 /* The effect of all that is that any conversion between any two
4936 types which are integral, floating, or enumeration types can be
4937 performed. */
4940 {
4943 /* Ignore any integer overflow caused by the cast. */
4946 }
4955 {
4956 tree base;
4962 NULL);
4964 }
4968 {
4969 tree c1;
4970 tree c2;
4971 tree t1;
4972 tree t2;
4978 {
4979 t1 = (build_ptrmem_type
4982 t2 = (build_ptrmem_type
4985 }
4986 else
4987 {
4990 }
4992 {
4995 desc);
4997 c_cast_p);
4998 }
4999 }
5001 /* [expr.static.cast]
5003 An rvalue of type "pointer to cv void" can be explicitly
5004 converted to a pointer to object type. A value of type pointer
5005 to object converted to "pointer to cv void" and back to the
5006 original pointer type will have its original value. */
5010 {
5014 }
5018 }
5020 /* Return an expression representing static_cast<TYPE>(EXPR). */
5022 tree
5024 {
5025 tree result;
5032 {
5034 /* We don't know if it will or will not have side effects. */
5037 }
5039 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5040 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5053 }
5055 /* EXPR is an expression with member function or pointer-to-member
5056 function type. TYPE is a pointer type. Converting EXPR to TYPE is
5057 not permitted by ISO C++, but we accept it in some modes. If we
5058 are not in one of those modes, issue a diagnostic. Return the
5059 converted expression. */
5061 tree
5063 {
5064 tree intype;
5065 tree decl;
5078 else
5079 {
5083 }
5086 }
5088 /* Return a representation for a reinterpret_cast from EXPR to TYPE.
5089 If C_CAST_P is true, this reinterpret cast is being done as part of
5090 a C-style cast. If VALID_P is non-NULL, *VALID_P is set to
5091 indicate whether or not reinterpret_cast was valid. */
5093 static tree
5096 {
5097 tree intype;
5099 /* Assume the cast is invalid. */
5108 /* Save casted types in the function's used types hash table. */
5111 /* [expr.reinterpret.cast]
5112 An lvalue expression of type T1 can be cast to the type
5113 "reference to T2" if an expression of type "pointer to T1" can be
5114 explicitly converted to the type "pointer to T2" using a
5115 reinterpret_cast. */
5117 {
5119 {
5124 }
5126 /* Warn about a reinterpret_cast from "A*" to "B&" if "A" and
5127 "B" are related class types; the reinterpret_cast does not
5128 adjust the pointer. */
5137 expr = build_reinterpret_cast_1
5139 valid_p);
5143 }
5145 /* As a G++ extension, we consider conversions from member
5146 functions, and pointers to member functions to
5147 pointer-to-function and pointer-to-void types. If
5148 -Wno-pmf-conversions has not been specified,
5149 convert_member_func_to_ptr will issue an error message. */
5157 /* If the cast is not to a reference type, the lvalue-to-rvalue,
5158 array-to-pointer, and function-to-pointer conversions are
5159 performed. */
5162 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5163 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5173 /* [expr.reinterpret.cast]
5174 A pointer can be converted to any integral type large enough to
5175 hold it. */
5177 {
5181 }
5182 /* [expr.reinterpret.cast]
5183 A value of integral or enumeration type can be explicitly
5184 converted to a pointer. */
5186 /* OK */
5187 ;
5193 {
5199 /* Warn about possible alignment problems. */
5210 /* We need to strip nops here, because the frontend likes to
5211 create (int *)&a for array-to-pointer decay, instead of &a[0]. */
5216 }
5219 {
5221 /* Only issue a warning, as we have always supported this
5222 where possible, and it is necessary in some cases. DR 195
5223 addresses this issue, but as of 2004/10/26 is still in
5224 drafting. */
5227 }
5232 else
5233 {
5238 }
5241 }
5243 tree
5245 {
5250 {
5255 /* There might turn out to be side effects inside expr. */
5258 }
5262 }
5264 /* Perform a const_cast from EXPR to TYPE. If the cast is valid,
5265 return an appropriate expression. Otherwise, return
5266 error_mark_node. If the cast is not valid, and COMPLAIN is true,
5267 then a diagnostic will be issued. If VALID_P is non-NULL, we are
5268 performing a C-style cast, its value upon return will indicate
5269 whether or not the conversion succeeded. */
5271 static tree
5274 {
5275 tree src_type;
5276 tree reference_type;
5278 /* Callers are responsible for handling error_mark_node as a
5279 destination type. */
5281 /* In a template, callers should be building syntactic
5282 representations of casts, not using this machinery. */
5285 /* Assume the conversion is invalid. */
5290 {
5293 "which is not a pointer, "
5296 }
5299 {
5304 }
5306 /* Save casted types in the function's used types hash table. */
5310 /* Expressions do not really have reference types. */
5314 /* [expr.const.cast]
5316 An lvalue of type T1 can be explicitly converted to an lvalue of
5317 type T2 using the cast const_cast<T2&> (where T1 and T2 are object
5318 types) if a pointer to T1 can be explicitly converted to the type
5319 pointer to T2 using a const_cast. */
5321 {
5324 {
5329 }
5332 }
5333 else
5334 {
5336 /* If the destination type is not a reference type, the
5337 lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5338 conversions are performed. */
5342 }
5346 {
5348 {
5350 /* This cast is actually a C-style cast. Issue a warning if
5351 the user is making a potentially unsafe cast. */
5354 warning0,
5356 }
5358 {
5362 }
5363 else
5364 {
5366 /* build_c_cast puts on a NOP_EXPR to make the result not an
5367 lvalue. Strip such NOP_EXPRs if VALUE is being used in
5368 non-lvalue context. */
5373 }
5374 }
5380 }
5382 tree
5384 {
5389 {
5394 /* There might turn out to be side effects inside expr. */
5397 }
5401 }
5403 /* Build an expression representing an explicit C-style cast to type
5404 TYPE of expression EXPR. */
5406 tree
5408 {
5410 tree result;
5417 {
5420 /* We don't know if it will or will not have side effects. */
5423 }
5425 /* Casts to a (pointer to a) specific ObjC class (or 'id' or
5426 'Class') should always be retained, because this information aids
5427 in method lookup. */
5432 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5433 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5440 {
5441 /* Allow casting from T1* to T2[] because Cfront allows it.
5442 NIHCL uses it. It is not valid ISO C++ however. */
5444 {
5447 }
5448 else
5449 {
5452 }
5453 }
5457 {
5460 }
5462 /* A C-style cast can be a const_cast. */
5468 /* Or a static cast. */
5471 /* Or a reinterpret_cast. */
5475 /* The static_cast or reinterpret_cast may be followed by a
5476 const_cast. */
5478 /* A valid cast may result in errors if, for example, a
5479 conversion to am ambiguous base class is required. */
5481 {
5482 tree result_type;
5484 /* Non-class rvalues always have cv-unqualified type. */
5490 /* If the type of RESULT does not match TYPE, perform a
5491 const_cast to make it match. If the static_cast or
5492 reinterpret_cast succeeded, we will differ by at most
5493 cv-qualification, so the follow-on const_cast is guaranteed
5494 to succeed. */
5496 {
5499 }
5501 }
5504 }
5505 \f
5506 /* Build an assignment expression of lvalue LHS from value RHS.
5507 MODIFYCODE is the code for a binary operator that we use
5508 to combine the old value of LHS with RHS to get the new value.
5509 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
5511 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */
5513 tree
5515 {
5516 tree result;
5523 /* Avoid duplicate error messages from operands that had errors. */
5527 /* Handle control structure constructs used as "lvalues". */
5529 {
5530 /* Handle --foo = 5; as these are valid constructs in C++. */
5538 lhs,
5542 /* Handle (a, b) used as an "lvalue". */
5563 /* MIN_EXPR and MAX_EXPR are currently only permitted as lvalues,
5564 when neither operand has side-effects. */
5573 boolean_type_node,
5578 /* Fall through. */
5580 /* Handle (a ? b : c) used as an "lvalue". */
5582 {
5583 /* Produce (a ? (b = rhs) : (c = rhs))
5584 except that the RHS goes through a save-expr
5585 so the code to compute it is only emitted once. */
5586 tree cond;
5591 /* Check this here to avoid odd errors when trying to convert
5592 a throw to the type of the COND_EXPR. */
5596 cond = build_conditional_expr
5605 /* Make sure the code to compute the rhs comes out
5606 before the split. */
5610 }
5614 }
5617 {
5619 {
5621 /* Call convert to generate an error; see PR 11063. */
5626 }
5629 else
5630 {
5637 }
5638 }
5639 else
5640 {
5646 {
5647 /* `operator=' is not an inheritable operator. */
5650 else
5651 {
5658 }
5660 }
5661 else
5662 {
5663 /* A binary op has been requested. Combine the old LHS
5664 value with the RHS producing the value we should actually
5665 store into the LHS. */
5671 {
5675 }
5677 /* Now it looks like a plain assignment. */
5679 }
5682 }
5684 /* The left-hand side must be an lvalue. */
5688 /* Warn about modifying something that is `const'. Don't warn if
5689 this is initialization. */
5692 /* Functions are not modifiable, even though they are
5693 lvalues. */
5696 /* If it's an aggregate and any field is const, then it is
5697 effectively const. */
5702 /* If storing into a structure or union member, it has probably been
5703 given type `int'. Compute the type that would go with the actual
5704 amount of storage the member occupies. */
5710 {
5713 /* If storing in a field that is in actuality a short or narrower
5714 than one, we must store in the field in its actual type. */
5717 {
5718 /* Avoid warnings converting integral types back into enums for
5719 enum bit fields. */
5722 {
5726 }
5729 }
5730 }
5732 /* Convert new value to destination type. */
5735 {
5740 {
5744 }
5746 /* Allow array assignment in compiler-generated code. */
5748 {
5749 /* This routine is used for both initialization and assignment.
5750 Make sure the diagnostic message differentiates the context. */
5753 else
5756 }
5762 from_array);
5763 }
5768 else
5769 {
5770 /* Avoid warnings on enum bit fields. */
5773 {
5777 }
5778 else
5785 /* Can't initialize directly from a TARGET_EXPR, since that would
5786 cause the lhs to be constructed twice, and possibly result in
5787 accidental self-initialization. So we force the TARGET_EXPR to be
5788 expanded without a target. */
5792 }
5798 {
5803 }
5812 /* If we got the LHS in a different type for storing in,
5813 convert the result back to the nominal type of LHS
5814 so that the value we return always has the same type
5815 as the LHS argument. */
5820 {
5824 }
5827 }
5829 tree
5831 {
5837 {
5842 {
5845 }
5846 }
5848 }
5850 \f
5851 /* Get difference in deltas for different pointer to member function
5852 types. Returns an integer constant of type PTRDIFF_TYPE_NODE. If
5853 the conversion is invalid, the constant is zero. If
5854 ALLOW_INVERSE_P is true, then allow reverse conversions as well.
5855 If C_CAST_P is true this conversion is taking place as part of a
5856 C-style cast.
5858 Note that the naming of FROM and TO is kind of backwards; the return
5859 value is what we add to a TO in order to get a FROM. They are named
5860 this way because we call this function to find out how to convert from
5861 a pointer to member of FROM to a pointer to member of TO. */
5863 static tree
5867 {
5868 tree binfo;
5869 base_kind kind;
5870 tree result;
5872 /* Assume no conversion is required. */
5878 {
5881 else
5882 {
5885 /* This is a reinterpret cast, we choose to do nothing. */
5889 else
5892 }
5893 }
5897 {
5900 }
5901 else
5902 {
5905 {
5908 else
5909 {
5910 /* This is a reinterpret cast, we choose to do nothing. */
5915 }
5916 }
5917 }
5920 result));
5921 }
5923 /* Return a constructor for the pointer-to-member-function TYPE using
5924 the other components as specified. */
5926 tree
5928 {
5930 tree delta_field;
5931 tree pfn_field;
5934 /* Pull the FIELD_DECLs out of the type. */
5938 /* Make sure DELTA has the type we want. */
5941 /* Finish creating the initializer. */
5954 }
5956 /* Build a constructor for a pointer to member function. It can be
5957 used to initialize global variables, local variable, or used
5958 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we
5959 want to be.
5961 If FORCE is nonzero, then force this conversion, even if
5962 we would rather not do it. Usually set when using an explicit
5963 cast. A C-style cast is being processed iff C_CAST_P is true.
5965 Return error_mark_node, if something goes wrong. */
5967 tree
5969 {
5970 tree fn;
5971 tree pfn_type;
5972 tree to_type;
5980 /* Handle multiple conversions of pointer to member functions. */
5982 {
5985 tree n;
5994 force,
5995 c_cast_p);
5997 /* We don't have to do any conversion to convert a
5998 pointer-to-member to its own type. But, we don't want to
5999 just return a PTRMEM_CST if there's an explicit cast; that
6000 cast should make the expression an invalid template argument. */
6002 {
6007 }
6012 /* Obtain the function pointer and the current DELTA. */
6015 else
6016 {
6019 }
6021 /* Just adjust the DELTA field. */
6028 }
6030 /* Handle null pointer to member function conversions. */
6032 {
6035 integer_zero_node,
6036 pfn);
6037 }
6044 /* In a template, we will have preserved the
6045 OFFSET_REF. */
6048 }
6050 /* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST
6051 given by CST.
6053 ??? There is no consistency as to the types returned for the above
6054 values. Some code acts as if it were a sizetype and some as if it were
6055 integer_type_node. */
6057 void
6059 {
6066 /* The class that the function belongs to. */
6069 /* The class that we're creating a pointer to member of. */
6072 /* First, calculate the adjustment to the function's class. */
6078 else
6079 {
6080 /* If we're dealing with a virtual function, we have to adjust 'this'
6081 again, to point to the base which provides the vtable entry for
6082 fn; the call will do the opposite adjustment. */
6089 /* We set PFN to the vtable offset at which the function can be
6090 found, plus one (unless ptrmemfunc_vbit_in_delta, in which
6091 case delta is shifted left, and then incremented). */
6098 {
6101 integer_one_node);
6116 }
6120 }
6121 }
6123 /* Return an expression for PFN from the pointer-to-member function
6124 given by T. */
6126 static tree
6128 {
6130 {
6131 tree delta;
6132 tree pfn;
6137 }
6140 }
6142 /* Convert value RHS to type TYPE as preparation for an assignment to
6143 an lvalue of type TYPE. ERRTYPE is a string to use in error
6144 messages: "assignment", "return", etc. If FNDECL is non-NULL, we
6145 are doing the conversion in order to pass the PARMNUMth argument of
6146 FNDECL. */
6148 static tree
6151 {
6152 tree rhstype;
6155 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
6171 /* The RHS of an assignment cannot have void type. */
6173 {
6176 }
6178 /* Simplify the RHS if possible. */
6183 {
6191 else
6192 {
6198 {
6201 }
6202 }
6206 }
6208 /* [expr.ass]
6210 The expression is implicitly converted (clause _conv_) to the
6211 cv-unqualified type of the left operand.
6213 We allow bad conversions here because by the time we get to this point
6214 we are committed to doing the conversion. If we end up doing a bad
6215 conversion, convert_like will complain. */
6217 {
6218 /* When -Wno-pmf-conversions is use, we just silently allow
6219 conversions from pointers-to-members to plain pointers. If
6220 the conversion doesn't work, cp_convert will complain. */
6225 else
6226 {
6227 /* If the right-hand side has unknown type, then it is an
6228 overloaded function. Call instantiate_type to get error
6229 messages. */
6235 else
6238 }
6239 }
6241 {
6248 errtype);
6249 }
6252 }
6254 /* Convert RHS to be of type TYPE.
6255 If EXP is nonzero, it is the target of the initialization.
6256 ERRTYPE is a string to use in error messages.
6258 Two major differences between the behavior of
6259 `convert_for_assignment' and `convert_for_initialization'
6260 are that references are bashed in the former, while
6261 copied in the latter, and aggregates are assigned in
6262 the former (operator=) while initialized in the
6263 latter (X(X&)).
6265 If using constructor make sure no conversion operator exists, if one does
6266 exist, an ambiguity exists.
6268 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */
6270 tree
6273 {
6275 tree rhstype;
6278 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
6279 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */
6306 /* We accept references to incomplete types, so we can
6307 return here before checking if RHS is of complete type. */
6310 {
6311 /* This should eventually happen in convert_arguments. */
6319 {
6324 }
6326 }
6341 }
6342 \f
6343 /* If RETVAL is the address of, or a reference to, a local variable or
6344 temporary give an appropriate warning. */
6346 static void
6348 {
6353 {
6360 else
6362 }
6369 {
6372 {
6375 }
6379 {
6382 }
6383 }
6394 {
6397 whats_returned);
6398 else
6400 whats_returned);
6402 }
6403 }
6405 /* Check that returning RETVAL from the current function is valid.
6406 Return an expression explicitly showing all conversions required to
6407 change RETVAL into the function return type, and to assign it to
6408 the DECL_RESULT for the function. Set *NO_WARNING to true if
6409 code reaches end of non-void function warning shouldn't be issued
6410 on this RETURN_EXPR. */
6412 tree
6414 {
6415 tree result;
6416 /* The type actually returned by the function, after any
6417 promotions. */
6418 tree valtype;
6423 /* A `volatile' function is one that isn't supposed to return, ever.
6424 (This is a G++ extension, used to get better code for functions
6425 that call the `volatile' function.) */
6429 /* Check for various simple errors. */
6431 {
6435 }
6437 {
6439 /* If a return statement appears in a handler of the
6440 function-try-block of a constructor, the program is ill-formed. */
6443 /* You can't return a value from a constructor. */
6446 }
6449 {
6452 }
6454 /* When no explicit return-value is given in a function with a named
6455 return value, the named return value is used. */
6463 /* Check for a return statement with no return value in a function
6464 that's supposed to return a value. */
6466 {
6468 valtype);
6469 /* Clear this, so finish_function won't say that we reach the
6470 end of a non-void function (which we don't, we gave a
6471 return!). */
6473 /* And signal caller that TREE_NO_WARNING should be set on the
6474 RETURN_EXPR to avoid control reaches end of non-void function
6475 warnings in tree-cfg.c. */
6477 }
6478 /* Check for a return statement with a value in a function that
6479 isn't supposed to return a value. */
6481 {
6483 /* You can return a `void' value from a function of `void'
6484 type. In that case, we have to evaluate the expression for
6485 its side-effects. */
6487 else
6493 /* There's really no value to return, after all. */
6495 }
6497 /* Remember that this function can sometimes return without a
6498 value. */
6500 else
6501 /* Remember that this function did return a value. */
6504 /* Check for erroneous operands -- but after giving ourselves a
6505 chance to provide an error about returning a value from a void
6506 function. */
6508 {
6511 }
6513 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */
6517 && ! flag_check_new
6522 /* Effective C++ rule 15. See also start_function. */
6525 {
6528 /* The function return type must be a reference to the current
6529 class. */
6531 && same_type_ignoring_top_level_qualifiers_p
6533 {
6534 /* Returning '*this' is obviously OK. */
6537 /* If we are calling a function whose return type is the same of
6538 the current class reference, it is ok. */
6542 }
6546 }
6548 /* The fabled Named Return Value optimization, as per [class.copy]/15:
6550 [...] For a function with a class return type, if the expression
6551 in the return statement is the name of a local object, and the cv-
6552 unqualified type of the local object is the same as the function
6553 return type, an implementation is permitted to omit creating the tem-
6554 porary object to hold the function return value [...]
6556 So, if this is a value-returning function that always returns the same
6557 local variable, remember it.
6559 It might be nice to be more flexible, and choose the first suitable
6560 variable even if the function sometimes returns something else, but
6561 then we run the risk of clobbering the variable we chose if the other
6562 returned expression uses the chosen variable somehow. And people expect
6563 this restriction, anyway. (jason 2000-11-19)
6565 See finish_function and finalize_nrv for the rest of this optimization. */
6568 {
6579 (TYPE_MAIN_VARIANT
6582 else
6584 }
6586 /* We don't need to do any conversions when there's nothing being
6587 returned. */
6591 /* Do any required conversions. */
6593 /* No conversions are required. */
6594 ;
6595 else
6596 {
6597 /* The type the function is declared to return. */
6600 /* The functype's return type will have been set to void, if it
6601 was an incomplete type. Just treat this as 'return;' */
6605 /* First convert the value to the function's return type, then
6606 to the type of return value's location to handle the
6607 case that functype is smaller than the valtype. */
6608 retval = convert_for_initialization
6613 /* If the conversion failed, treat this just like `return;'. */
6616 /* We can't initialize a register from a AGGR_INIT_EXPR. */
6622 else
6624 }
6626 /* Actually copy the value returned into the appropriate location. */
6631 }
6633 \f
6634 /* Returns nonzero if the pointer-type FROM can be converted to the
6635 pointer-type TO via a qualification conversion. If CONSTP is -1,
6636 then we return nonzero if the pointers are similar, and the
6637 cv-qualification signature of FROM is a proper subset of that of TO.
6639 If CONSTP is positive, then all outer pointers have been
6640 const-qualified. */
6642 static int
6644 {
6648 {
6657 /* Const and volatile mean something different for function types,
6658 so the usual checks are not appropriate. */
6660 {
6661 /* In Objective-C++, some types may have been 'volatilized' by
6662 the compiler for EH; when comparing them here, the volatile
6663 qualification must be ignored. */
6670 {
6674 }
6678 }
6683 }
6684 }
6686 /* When comparing, say, char ** to char const **, this function takes
6687 the 'char *' and 'char const *'. Do not pass non-pointer/reference
6688 types to this function. */
6690 int
6692 {
6694 }
6696 /* Returns 1 if to and from are (possibly multi-level) pointers to the same
6697 type or inheritance-related types, regardless of cv-quals. */
6699 int
6701 {
6703 {
6704 /* Any target type is similar enough to void. */
6730 return comptypes
6733 }
6734 }
6736 /* Return true if TO and FROM (both of which are POINTER_TYPEs or
6737 pointer-to-member types) are the same, ignoring cv-qualification at
6738 all levels. */
6740 bool
6742 {
6744 {
6755 }
6756 }
6758 /* Returns the type qualifiers for this type, including the qualifiers on the
6759 elements for an array type. */
6761 int
6763 {
6768 }
6770 /* Returns nonzero if the TYPE contains a mutable member. */
6772 bool
6774 {
6778 }
6780 /* Apply the TYPE_QUALS to the new DECL. */
6781 void
6783 {
6791 {
6792 /* This was an error in C++98 (cv-qualifiers cannot be added to
6793 a function type), but DR 295 makes the code well-formed by
6794 dropping the extra qualifiers. */
6796 {
6800 }
6804 }
6806 /* Avoid setting TREE_READONLY incorrectly. */
6808 the object. */
6810 /* If the type isn't complete, we don't know yet if it will need
6811 constructing. */
6813 /* If the type has a mutable component, that component might be
6814 modified. */
6819 }
6821 /* Subroutine of casts_away_constness. Make T1 and T2 point at
6822 exemplar types such that casting T1 to T2 is casting away constness
6823 if and only if there is no implicit conversion from T1 to T2. */
6825 static void
6827 {
6831 /* [expr.const.cast]
6833 For multi-level pointer to members and multi-level mixed pointers
6834 and pointers to members (conv.qual), the "member" aspect of a
6835 pointer to member level is ignored when determining if a const
6836 cv-qualifier has been cast away. */
6837 /* [expr.const.cast]
6839 For two pointer types:
6841 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type
6842 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type
6843 K is min(N,M)
6845 casting from X1 to X2 casts away constness if, for a non-pointer
6846 type T there does not exist an implicit conversion (clause
6847 _conv_) from:
6849 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N *
6851 to
6853 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */
6856 {
6862 }
6869 else
6873 else
6881 }
6883 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
6884 constness. */
6886 static bool
6888 {
6890 {
6891 /* [expr.const.cast]
6893 Casting from an lvalue of type T1 to an lvalue of type T2
6894 using a reference cast casts away constness if a cast from an
6895 rvalue of type "pointer to T1" to the type "pointer to T2"
6896 casts away constness. */
6900 }
6903 /* [expr.const.cast]
6905 Casting from an rvalue of type "pointer to data member of X
6906 of type T1" to the type "pointer to data member of Y of type
6907 T2" casts away constness if a cast from an rvalue of type
6908 "pointer to T1" to the type "pointer to T2" casts away
6909 constness. */
6910 return casts_away_constness
6914 /* Casting away constness is only something that makes sense for
6915 pointer or reference types. */
6920 /* Top-level qualifiers don't matter. */
6928 }
6930 /* If T is a REFERENCE_TYPE return the type to which T refers.
6931 Otherwise, return T itself. */
6933 tree
6935 {
6939 }
6942 /* Return nonzero if REF is an lvalue valid for this language;
6943 otherwise, print an error message and return zero. USE says
6944 how the lvalue is being used and so selects the error message. */
6946 int
6948 {
6955 }