| blob | 06a0b420705b5eae348aa0b352f3a60fb72e783f |
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 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, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, 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.
29 There are also routines to build RETURN_STMT nodes and CASE_STMT nodes,
30 and to process initializations in declarations (since they work
31 like a strange sort of assignment). */
71 /* Return the target type of TYPE, which means return T for:
72 T*, T&, T[], T (...), and otherwise, just T. */
74 tree
76 tree type;
77 {
87 }
89 /* Do `exp = require_complete_type (exp);' to make sure exp
90 does not have an incomplete type. (That includes void types.)
91 Returns the error_mark_node if the VALUE does not have
92 complete type when this function returns. */
94 tree
96 tree value;
97 {
98 tree type;
105 else
108 /* First, detect a valid value with a complete type. */
112 /* If we see X::Y, we build an OFFSET_TYPE which has
113 not been laid out. Try to avoid an error by interpreting
114 it as this->X::Y, if reasonable. */
118 {
121 }
125 else
127 }
129 /* Try to complete TYPE, if it is incomplete. For example, if TYPE is
130 a template instantiation, do the instantiation. Returns TYPE,
131 whether or not it could be completed, unless something goes
132 horribly wrong, in which case the error_mark_node is returned. */
134 tree
136 tree type;
137 {
139 /* Rather than crash, we return something sure to cause an error
140 at some point. */
144 ;
146 {
154 }
159 }
161 /* Like complete_type, but issue an error if the TYPE cannot be completed.
162 VALUE is used for informative diagnostics. DIAG_TYPE indicates the type
163 of diagnostic: 0 for an error, 1 for a warning, 2 for a pedwarn.
164 Returns NULL_TREE if the type cannot be made complete. */
166 tree
168 tree type;
169 tree value;
171 {
174 /* We already issued an error. */
177 {
180 }
181 else
183 }
185 /* Return truthvalue of whether type of EXP is instantiated. */
187 int
189 tree exp;
190 {
196 }
198 /* Return a pointer or pointer to member type similar to T1, with a
199 cv-qualification signature that is the union of the cv-qualification
200 signatures of T1 and T2: [expr.rel], [expr.eq]. */
202 static tree
205 {
208 {
209 tree tt1;
210 tree tt2;
211 tree b1;
213 tree tgt;
217 {
221 }
222 else
223 {
227 }
234 else
237 }
239 }
240 \f
241 /* Return the common type of two parameter lists.
242 We assume that comptypes has already been done and returned 1;
243 if that isn't so, this may crash.
245 As an optimization, free the space we allocate if the parameter
246 lists are already common. */
248 tree
251 {
261 else
262 {
265 }
274 {
276 {
279 }
281 {
283 {
286 }
287 }
288 else
289 {
293 }
295 {
298 }
299 else
301 }
306 }
308 /* Given a type, perhaps copied for a typedef,
309 find the "original" version of it. */
310 tree
312 tree t;
313 {
315 {
323 }
325 }
327 /* T1 and T2 are arithmetic or enumeration types. Return the type
328 that will result from the "usual arithmetic conversions" on T1 and
329 T2 as described in [expr]. */
331 tree
333 tree t1;
334 tree t2;
335 {
338 tree attributes;
340 /* FIXME: Attributes. */
350 /* In what follows, we slightly generalize the rules given in [expr] so
351 as to deal with `long long' and `complex'. First, merge the
352 attributes. */
355 /* If one type is complex, form the common type of the non-complex
356 components, then make that complex. Use T1 or T2 if it is the
357 required type. */
359 {
362 tree subtype
369 else
371 attributes);
372 }
374 /* If only one is real, use it as the result. */
380 /* Perform the integral promotions. */
382 {
385 }
387 /* Both real or both integers; use the one with greater precision. */
393 /* The types are the same; no need to do anything fancy. */
398 {
399 /* If one is a sizetype, use it so size_binop doesn't blow up. */
405 /* If one is unsigned long long, then convert the other to unsigned
406 long long. */
410 attributes);
411 /* If one is a long long, and the other is an unsigned long, and
412 long long can represent all the values of an unsigned long, then
413 convert to a long long. Otherwise, convert to an unsigned long
414 long. Otherwise, if either operand is long long, convert the
415 other to long long.
417 Since we're here, we know the TYPE_PRECISION is the same;
418 therefore converting to long long cannot represent all the values
419 of an unsigned long, so we choose unsigned long long in that
420 case. */
423 {
425 ? long_long_unsigned_type_node
428 }
430 /* Go through the same procedure, but for longs. */
434 attributes);
437 {
441 }
442 /* Otherwise prefer the unsigned one. */
445 else
447 }
448 else
449 {
453 attributes);
457 attributes);
461 attributes);
463 /* Two floating-point types whose TYPE_MAIN_VARIANTs are none of
464 the standard C++ floating-point types. Logic earlier in this
465 function has already eliminated the possibility that
466 TYPE_PRECISION (t2) != TYPE_PRECISION (t1), so there's no
467 compelling reason to choose one or the other. */
469 }
470 }
472 /* Return the composite pointer type (see [expr.rel]) for T1 and T2.
473 ARG1 and ARG2 are the values with those types. The LOCATION is a
474 string describing the current location, in case an error occurs. */
476 tree
478 tree t1;
479 tree t2;
480 tree arg1;
481 tree arg2;
483 {
484 tree result_type;
485 tree attributes;
487 /* [expr.rel]
489 If one operand is a null pointer constant, the composite pointer
490 type is the type of the other operand. */
496 /* Deal with pointer-to-member functions in the same way as we deal
497 with pointers to functions. */
503 /* Merge the attributes. */
506 /* We have:
508 [expr.rel]
510 If one of the operands has type "pointer to cv1 void*", then
511 the other has type "pointer to cv2T", and the composite pointer
512 type is "pointer to cv12 void", where cv12 is the union of cv1
513 and cv2.
515 If either type is a pointer to void, make sure it is T1. */
517 {
518 tree t;
522 }
523 /* Now, if T1 is a pointer to void, merge the qualifiers. */
525 {
527 pedwarn ("ISO C++ forbids %s between pointer of type `void *' and pointer-to-function", location);
534 }
535 else
536 {
546 else
547 {
551 }
552 }
555 }
557 /* Return the merged type of two types.
558 We assume that comptypes has already been done and returned 1;
559 if that isn't so, this may crash.
561 This just combines attributes and default arguments; any other
562 differences would cause the two types to compare unalike. */
564 tree
567 {
570 tree attributes;
572 /* Save time if the two types are the same. */
578 /* If one type is nonsense, use the other. */
584 /* Merge the attributes. */
587 /* Treat an enum type as the unsigned integer type of the same width. */
598 {
601 /* For two pointers, do this recursively on the target type. */
602 {
608 else
617 }
620 {
625 }
628 {
630 /* Save space: see if the result is identical to one of the args. */
635 /* Merge the element types, and have a size if either arg has one. */
636 t1 = build_cplus_array_type
639 }
642 /* Function types: prefer the one that specified arg types.
643 If both do, merge the arg types. Also merge the return types. */
644 {
650 /* Save space: see if the result is identical to one of the args. */
656 /* Simple way if one arg fails to specify argument types. */
658 {
663 }
666 {
671 }
676 }
679 {
680 /* Get this value the long way, since TYPE_METHOD_BASETYPE
681 is just the main variant of this. */
684 tree t3;
686 /* If this was a member function type, get back to the
687 original type of type member function (i.e., without
688 the class instance variable up front. */
698 }
701 }
703 }
705 /* Return the common type of two types.
706 We assume that comptypes has already been done and returned 1;
707 if that isn't so, this may crash.
709 This is the type for the result of most arithmetic operations
710 if the operands have the given two types. */
712 tree
715 {
719 /* If one type is nonsense, bail. */
738 else
740 }
741 \f
742 /* Compare two exception specifier types for exactness or subsetness, if
743 allowed. Returns 0 for mismatch, 1 for same, 2 if B is allowed by A.
745 [except.spec] "If a class X ... objects of class X or any class publicly
746 and unambigously derrived from X. Similarly, if a pointer type Y * ...
747 exceptions of type Y * or that are pointers to any type publicly and
748 unambigously derrived from Y. Otherwise a function only allows exceptions
749 that have the same type ..."
750 This does not mention cv qualifiers and is different to what throw
751 [except.throw] and catch [except.catch] will do. They will ignore the
752 top level cv qualifiers, and allow qualifiers in the pointer to class
753 example.
755 We implement the letter of the standard. */
757 static int
761 {
765 {
771 {
776 }
784 }
786 }
788 /* Return 1 if TYPE1 and TYPE2 are equivalent exception specifiers.
789 If EXACT is 0, T2 can be stricter than T1 (according to 15.4/7),
790 otherwise it must be exact. Exception lists are unordered, but
791 we've already filtered out duplicates. Most lists will be in order,
792 we should try to make use of that. */
794 int
798 {
799 tree probe;
800 tree base;
815 /* Neither set is ... or EMPTY, make sure each part of T2 is in T1.
816 Count how many we find, to determine exactness. For exact matching and
817 ordered T1, T2, this is an O(n) operation, otherwise its worst case is
818 O(nm). */
820 {
822 {
827 {
830 length++;
832 }
833 }
836 }
838 }
840 /* Compare the array types T1 and T2, using CMP as the type comparison
841 function for the element types. STRICT is as for comptypes. */
843 static int
848 {
849 tree d1;
850 tree d2;
855 /* The type of the array elements must be the same. */
867 /* If one of the arrays is dimensionless, and the other has a
868 dimension, they are of different types. However, it is valid to
869 write:
871 extern int a[];
872 int a[3];
874 by [basic.link]:
876 declarations for an array object can specify
877 array types that differ by the presence or absence of a major
878 array bound (_dcl.array_). */
882 /* Check that the dimensions are the same. */
887 }
889 /* Return 1 if T1 and T2 are compatible types for assignment or
890 various other operations. STRICT is a bitwise-or of the COMPARE_*
891 flags. */
893 int
895 tree t1;
896 tree t2;
898 {
902 /* The special exemption for redeclaring array types without an
903 array bound only applies at the top level:
905 extern int (*i)[];
906 int (*i)[8];
908 is invalid, for example. */
911 /* Suppress errors caused by previously reported errors */
915 /* This should never happen. */
921 /* If either type is the internal version of sizetype, return the
922 language version. */
932 {
933 /* Treat an enum type as the unsigned integer type of the same width. */
942 }
949 /* TYPENAME_TYPEs should be resolved if the qualifying scope is the
950 current instantiation. */
956 /* Different classes of types can't be compatible. */
960 /* Qualifiers must match. */
967 /* Allow for two different type nodes which have essentially the same
968 definition. Note that we already checked for equality of the type
969 qualifiers (just above). */
976 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
980 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
984 {
996 /* Don't check inheritance. */
998 /* fall through */
1007 look_hard:
1024 /* first, check whether the referred types match with the
1025 required level of strictness */
1042 /* Target types must match incl. qualifiers. We use ORIG_STRICT
1043 here since this is the one place where
1044 COMPARE_REDECLARATION should be used. */
1069 }
1071 }
1073 /* Subroutine of comp_target-types. Make sure that the cv-quals change
1074 only in the same direction as the target type. */
1076 static int
1080 {
1085 /* The qualifications are incomparable. */
1097 }
1099 /* Return 1 or -1 if TTL and TTR are pointers to types that are equivalent,
1100 ignoring their qualifiers, 0 if not. Return 1 means that TTR can be
1101 converted to TTL. Return -1 means that TTL can be converted to TTR but
1102 not vice versa.
1104 NPTRS is the number of pointers we can strip off and keep cool.
1105 This is used to permit (for aggr A, aggr B) A, B* to convert to A*,
1106 but to not permit B** to convert to A**.
1108 This should go away. Callers should use can_convert or something
1109 similar instead. (jason 17 Apr 1997) */
1111 int
1115 {
1126 /* If we get a pointer with nptrs == 0, we don't allow any tweaking
1127 of the type pointed to. This is necessary for reference init
1128 semantics. We won't get here from a previous call with nptrs == 1;
1129 for multi-level pointers we end up in comp_ptr_ttypes. */
1131 {
1138 {
1154 {
1160 }
1161 }
1163 /* Const and volatile mean something different for function types,
1164 so the usual checks are not appropriate. */
1169 }
1174 {
1179 {
1182 }
1183 else
1184 {
1186 {
1191 }
1192 }
1197 /* Compare 'this' here, not in comp_target_parms. */
1199 {
1204 {
1207 else
1209 }
1213 }
1216 {
1221 }
1224 }
1225 /* for C++ */
1227 {
1230 /* Contravariance: we can assign a pointer to base member to a pointer
1231 to derived member. Note difference from simple pointer case, where
1232 we can pass a pointer to derived to a pointer to base. */
1238 {
1243 }
1244 else
1252 {
1256 }
1257 else
1258 {
1262 }
1263 }
1265 {
1275 }
1278 }
1280 /* Returns 1 if TYPE1 is at least as qualified as TYPE2. */
1282 int
1284 tree type1;
1285 tree type2;
1286 {
1287 /* All qualifiers for TYPE2 must also appear in TYPE1. */
1290 }
1292 /* Returns 1 if TYPE1 is more qualified than TYPE2. */
1294 int
1296 tree type1;
1297 tree type2;
1298 {
1301 }
1303 /* Returns 1 if TYPE1 is more cv-qualified than TYPE2, -1 if TYPE2 is
1304 more cv-qualified that TYPE1, and 0 otherwise. */
1306 int
1308 tree type1;
1309 tree type2;
1310 {
1321 }
1323 /* Returns 1 if the cv-qualification signature of TYPE1 is a proper
1324 subset of the cv-qualification signature of TYPE2, and the types
1325 are similar. Returns -1 if the other way 'round, and 0 otherwise. */
1327 int
1329 tree type1;
1330 tree type2;
1331 {
1336 else
1338 }
1340 /* If two types share a common base type, return that basetype.
1341 If there is not a unique most-derived base type, this function
1342 returns ERROR_MARK_NODE. */
1344 static tree
1347 {
1351 /* If one is a baseclass of another, that's good enough. */
1357 /* Otherwise, try to find a unique baseclass of TT1
1358 that is shared by TT2, and follow that down. */
1360 {
1364 {
1371 }
1372 }
1374 /* Same for TT2. */
1376 {
1380 {
1387 }
1388 }
1390 }
1391 \f
1392 /* Subroutines of `comptypes'. */
1394 /* Return 1 if two parameter type lists PARMS1 and PARMS2 are
1395 equivalent in the sense that functions with those parameter types
1396 can have equivalent types. The two lists must be equivalent,
1397 element by element.
1399 C++: See comment above about TYPE1, TYPE2. */
1401 int
1404 {
1407 /* An unspecified parmlist matches any specified parmlist
1408 whose argument types don't need default promotions. */
1411 {
1414 /* If one parmlist is shorter than the other,
1415 they fail to match. */
1423 }
1424 }
1426 /* This really wants return whether or not parameter type lists
1427 would make their owning functions assignment compatible or not.
1429 The return value is like for comp_target_types.
1431 This should go away, possibly with the exception of the empty parmlist
1432 conversion; there are no conversions between function types in C++.
1433 (jason 17 Apr 1997) */
1435 static int
1438 {
1442 /* In C, an unspecified parmlist matches any specified parmlist
1443 whose argument types don't need default promotions. This is not
1444 true for C++, but let's do it anyway for unfixed headers. */
1447 {
1449 parms2);
1451 }
1456 {
1459 /* If one parmlist is shorter than the other,
1460 they fail to match, unless STRICT is <= 0. */
1474 {
1475 /* The following is wrong for contravariance,
1476 but many programs depend on it. */
1480 {
1483 }
1488 }
1489 /* Note backwards order due to contravariance. */
1491 {
1493 {
1496 }
1498 }
1499 }
1501 }
1502 \f
1503 tree
1505 tree type;
1508 {
1510 tree value;
1524 {
1528 }
1530 {
1534 }
1535 else
1539 }
1541 tree
1543 tree e;
1544 {
1552 {
1555 }
1557 {
1560 }
1561 /* It's invalid to say `sizeof (X::i)' for `i' a non-static data
1562 member unless you're in a non-static member of X. So hand off to
1563 resolve_offset_ref. [expr.prim] */
1571 }
1573 \f
1574 /* Perform the array-to-pointer and function-to-pointer conversions
1575 for EXP.
1577 In addition, references are converted to lvalues and manifest
1578 constants are replaced by their values. */
1580 tree
1582 tree exp;
1583 {
1594 {
1598 }
1604 {
1607 }
1609 /* Constants can be used directly unless they're not loadable. */
1612 /* Replace a nonvolatile const static variable with its value. We
1613 don't do this for arrays, though; we want the address of the
1614 first element of the array, not the address of the first element
1615 of its initializing constant. */
1617 {
1620 }
1622 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
1623 Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */
1626 {
1629 }
1635 {
1637 tree ptrtype;
1640 {
1641 /* Stripping away the INDIRECT_REF is not the right
1642 thing to do for references... */
1645 {
1649 inner);
1651 }
1653 }
1656 {
1660 }
1664 {
1667 }
1672 {
1673 /* ??? This is not really quite correct
1674 in that the type of the operand of ADDR_EXPR
1675 is not the target type of the type of the ADDR_EXPR itself.
1676 Question is, can this lossage be avoided? */
1683 }
1684 /* This way is better for a COMPONENT_REF since it can
1685 simplify the offset for a component. */
1688 }
1690 /* [basic.lval]: Class rvalues can have cv-qualified types; non-class
1691 rvalues always have cv-unqualified types. */
1696 }
1698 tree
1700 tree exp;
1701 {
1702 tree type;
1711 {
1715 }
1718 }
1720 /* Take the address of an inline function without setting TREE_ADDRESSABLE
1721 or TREE_USED. */
1723 tree
1725 tree exp;
1726 {
1731 }
1733 /* Returns nonzero iff exp is a STRING_CST or the result of applying
1734 decay_conversion to one. */
1736 int
1740 {
1741 tree t;
1752 {
1753 /* Make sure that we don't try to convert between char and wchar_t. */
1756 }
1757 else
1758 {
1759 /* Is this a string constant which has decayed to 'const char *'? */
1767 }
1769 /* This warning is not very useful, as it complains about printf. */
1774 }
1776 /* Given a COND_EXPR, MIN_EXPR, or MAX_EXPR in T, return it in a form that we
1777 can, for example, use as an lvalue. This code used to be in
1778 unary_complex_lvalue, but we needed it to deal with `a = (d == c) ? b : c'
1779 expressions, where we're dealing with aggregates. But now it's again only
1780 called from unary_complex_lvalue. The case (in particular) that led to
1781 this was with CODE == ADDR_EXPR, since it's not an lvalue when we'd
1782 get it there. */
1784 static tree
1787 tree t;
1788 {
1789 /* For MIN_EXPR or MAX_EXPR, fold-const.c has arranged things so that
1790 the first operand is always the one to be used if both operands
1791 are equal, so we know what conditional expression this used to be. */
1793 {
1794 return
1801 }
1803 return
1807 }
1809 /* Given the TYPE of an anonymous union field inside T, return the
1810 FIELD_DECL for the field. If not found return NULL_TREE. Because
1811 anonymous unions can nest, we must also search all anonymous unions
1812 that are directly reachable. */
1814 static tree
1817 {
1818 tree field;
1821 {
1827 /* If we find it directly, return the field. */
1830 {
1832 }
1834 /* Otherwise, it could be nested, search harder. */
1837 {
1841 }
1842 }
1844 }
1846 /* Build an expression representing OBJECT.MEMBER. OBJECT is an
1847 expression; MEMBER is a DECL or baselink. If ACCESS_PATH is
1848 non-NULL, it indicates the path to the base used to name MEMBER.
1849 If PRESERVE_REFERENCE is true, the expression returned will have
1850 REFERENCE_TYPE if the MEMBER does. Otherwise, the expression
1851 returned will have the type referred to by the reference.
1853 This function does not perform access control; that is either done
1854 earlier by the parser when the name of MEMBER is resolved to MEMBER
1855 itself, or later when overload resolution selects one of the
1856 functions indicated by MEMBER. */
1858 tree
1861 {
1862 tree object_type;
1863 tree member_scope;
1875 /* [expr.ref]
1877 The type of the first expression shall be "class object" (of a
1878 complete type). */
1883 {
1887 }
1889 /* The standard does not seem to actually say that MEMBER must be a
1890 member of OBJECT_TYPE. However, that is clearly what is
1891 intended. */
1893 {
1898 }
1899 else
1901 /* If MEMBER is from an anonymous aggregate, MEMBER_SCOPE will
1902 presently be the anonymous union. Go outwards until we find a
1903 type related to OBJECT_TYPE. */
1906 object_type))
1909 {
1912 }
1914 /* Transform `(a, b).x' into `(*(a, &b)).x', `(a ? b : c).x' into
1915 `(*(a ? &b : &c)).x', and so on. A COND_EXPR is only an lvalue
1916 in the frontend; only _DECLs and _REFs are lvalues in the backend. */
1917 {
1921 }
1923 /* In [expr.ref], there is an explicit list of the valid choices for
1924 MEMBER. We check for each of those cases here. */
1926 {
1927 /* A static data member. */
1929 /* If OBJECT has side-effects, they are supposed to occur. */
1932 }
1934 {
1935 /* A non-static data member. */
1938 tree member_type;
1943 /* Convert OBJECT to the type of MEMBER. */
1945 {
1946 tree binfo;
1947 base_kind kind;
1954 /* It is invalid to use to try to get to a virtual base of a
1955 NULL object. The most common cause is invalid use of
1956 offsetof macro. */
1958 {
1960 member);
1963 }
1965 /* Convert to the base. */
1968 /* If we found the base successfully then we should be able
1969 to convert to it successfully. */
1972 }
1974 /* Complain about other invalid uses of offsetof, even though they will
1975 give the right answer. Note that we complain whether or not they
1976 actually used the offsetof macro, since there's no way to know at this
1977 point. So we just give a warning, instead of a pedwarn. */
1979 {
1981 member);
1983 }
1985 /* If MEMBER is from an anonymous aggregate, we have converted
1986 OBJECT so that it refers to the class containing the
1987 anonymous union. Generate a reference to the anonymous union
1988 itself, and recur to find MEMBER. */
1990 /* When this code is called from build_field_call, the
1991 object already has the type of the anonymous union.
1992 That is because the COMPONENT_REF was already
1993 constructed, and was then disassembled before calling
1994 build_field_call. After the function-call code is
1995 cleaned up, this waste can be eliminated. */
1996 && (!same_type_ignoring_top_level_qualifiers_p
1998 {
1999 tree anonymous_union;
2004 anonymous_union,
2006 preserve_reference);
2007 }
2009 /* Compute the type of the field, as described in [expr.ref]. */
2013 {
2017 /* A field is const (volatile) if the enclosing object, or the
2018 field itself, is const (volatile). But, a mutable field is
2019 not const, even within a const object. */
2023 }
2027 /* Mark the expression const or volatile, as appropriate. Even
2028 though we've dealt with the type above, we still have to mark the
2029 expression itself. */
2034 }
2036 {
2037 /* The member is a (possibly overloaded) member function. */
2038 tree functions;
2039 tree type;
2041 /* If the MEMBER is exactly one static member function, then we
2042 know the type of the expression. Otherwise, we must wait
2043 until overload resolution has been performed. */
2048 else
2050 /* Note that we do not convert OBJECT to the BASELINK_BINFO
2051 base. That will happen when the function is called. */
2053 }
2055 {
2056 /* The member is an enumerator. */
2058 /* If OBJECT has side-effects, they are supposed to occur. */
2062 }
2063 else
2064 {
2067 }
2070 /* [expr.ref]
2072 If E2 is declared to have type "reference to T", then ... the
2073 type of E1.E2 is T. */
2077 }
2079 /* Return the destructor denoted by OBJECT.SCOPE::~DTOR_NAME, or, if
2080 SCOPE is NULL, by OBJECT.~DTOR_NAME. */
2082 static tree
2084 {
2089 {
2093 }
2095 {
2099 }
2102 dtor_type);
2105 }
2107 /* This function is called by the parser to process a class member
2108 access expression of the form OBJECT.NAME. NAME is a node used by
2109 the parser to represent a name; it is not yet a DECL. It may,
2110 however, be a BASELINK where the BASELINK_FUNCTIONS is a
2111 TEMPLATE_ID_EXPR. Templates must be looked up by the parser, and
2112 there is no reason to do the lookup twice, so the parser keeps the
2113 BASELINK. */
2115 tree
2117 {
2118 tree object_type;
2119 tree member;
2133 {
2136 }
2138 /* [expr.ref]
2140 The type of the first expression shall be "class object" (of a
2141 complete type). */
2145 {
2149 }
2152 {
2153 /* A member function that has already been looked up. */
2158 }
2159 else
2160 {
2165 {
2169 }
2172 {
2173 tree scope;
2175 /* A qualified name. The qualifying class or namespace `S' has
2176 already been looked up; it is either a TYPE or a
2177 NAMESPACE_DECL. The member name is either an IDENTIFIER_NODE
2178 or a BIT_NOT_EXPR. */
2188 /* If SCOPE is a namespace, then the qualified name does not
2189 name a member of OBJECT_TYPE. */
2191 {
2195 }
2197 /* Find the base of OBJECT_TYPE corresponding to SCOPE. */
2204 else
2205 {
2206 /* Look up the member. */
2210 {
2213 }
2216 }
2217 }
2221 {
2222 /* An unqualified name. */
2226 {
2229 }
2232 }
2233 else
2234 {
2235 /* The YACC parser sometimes gives us things that are not names.
2236 These always indicate errors. The recursive-descent parser
2237 does not do this, so this code can go away once that parser
2238 replaces the YACC parser. */
2241 }
2244 {
2251 template_args);
2252 else
2253 {
2256 }
2257 }
2258 }
2265 }
2267 /* Return an expression for the MEMBER_NAME field in the internal
2268 representation of PTRMEM, a pointer-to-member function. (Each
2269 pointer-to-member function type gets its own RECORD_TYPE so it is
2270 more convenient to access the fields by name than by FIELD_DECL.)
2271 This routine converts the NAME to a FIELD_DECL and then creates the
2272 node for the complete expression. */
2274 tree
2276 {
2277 tree ptrmem_type;
2278 tree member;
2279 tree member_type;
2281 /* This code is a stripped down version of
2282 build_class_member_access_expr. It does not work to use that
2283 routine directly because it expects the object to be of class
2284 type. */
2292 }
2294 /* Given an expression PTR for a pointer, return an expression
2295 for the value pointed to.
2296 ERRORSTRING is the name of the operator to appear in error messages.
2298 This function may need to overload OPERATOR_FNNAME.
2299 Must also handle REFERENCE_TYPEs for C++. */
2301 tree
2303 tree ptr;
2305 {
2306 tree rval;
2312 NULL_TREE);
2316 }
2318 tree
2320 tree ptr;
2322 {
2336 {
2337 /* [expr.unary.op]
2339 If the type of the expression is "pointer to T," the type
2340 of the result is "T."
2342 We must use the canonical variant because certain parts of
2343 the back end, like fold, do pointer comparisons between
2344 types. */
2348 {
2349 /* A pointer to incomplete type (other than cv void) can be
2350 dereferenced [expr.unary.op]/1 */
2353 }
2356 /* The POINTER was something like `&x'. We simplify `*&x' to
2357 `x'. */
2359 else
2360 {
2363 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
2364 so that we get the proper error message if the result is used
2365 to assign to. Also, &* is supposed to be a no-op. */
2371 }
2372 }
2373 /* `pointer' won't be an error_mark_node if we were given a
2374 pointer to member, so it's cool to check for this here. */
2378 {
2381 else
2383 }
2385 }
2387 /* This handles expressions of the form "a[i]", which denotes
2388 an array reference.
2390 This is logically equivalent in C to *(a+i), but we may do it differently.
2391 If A is a variable or a member, we generate a primitive ARRAY_REF.
2392 This avoids forcing the array out of registers, and can work on
2393 arrays that are not lvalues (for example, members of structures returned
2394 by functions).
2396 If INDEX is of some user-defined type, it must be converted to
2397 integer type. Otherwise, to make a compatible PLUS_EXPR, it
2398 will inherit the type of the array, which will be some pointer type. */
2400 tree
2403 {
2405 {
2408 }
2414 /* If ARRAY is a COMPOUND_EXPR or COND_EXPR, move our reference
2415 inside it. */
2417 {
2419 {
2423 }
2426 return build_conditional_expr
2433 }
2437 {
2440 /* Subscripting with type char is likely to lose
2441 on a machine where chars are signed.
2442 So warn on any machine, but optionally.
2443 Don't warn for unsigned char since that type is safe.
2444 Don't warn for signed char because anyone who uses that
2445 must have done so deliberately. */
2450 /* Apply default promotions *after* noticing character types. */
2454 {
2457 }
2459 /* An array that is indexed by a non-constant
2460 cannot be stored in a register; we must be able to do
2461 address arithmetic on its address.
2462 Likewise an array of elements of variable size. */
2467 {
2470 }
2472 /* An array that is indexed by a constant value which is not within
2473 the array bounds cannot be stored in a register either; because we
2474 would get a crash in store_bit_field/extract_bit_field when trying
2475 to access a non-existent part of the register. */
2479 {
2482 }
2487 /* Note in C++ it is valid to subscript a `register' array, since
2488 it is valid to take the address of something with that
2489 storage specification. */
2491 {
2497 }
2501 /* Array ref is const/volatile if the array elements are
2502 or if the array is.. */
2510 }
2512 {
2516 /* Put the integer in IND to simplify error checking. */
2518 {
2522 }
2528 {
2531 }
2533 {
2536 }
2540 }
2541 }
2542 \f
2543 /* Resolve a pointer to member function. INSTANCE is the object
2544 instance to use, if the member points to a virtual member.
2546 This used to avoid checking for virtual functions if basetype
2547 has no virtual functions, according to an earlier ANSI draft.
2548 With the final ISO C++ rules, such an optimization is
2549 incorrect: A pointer to a derived member can be static_cast
2550 to pointer-to-base-member, as long as the dynamic object
2551 later has the right member. */
2553 tree
2556 tree function;
2557 {
2562 {
2569 {
2571 {
2572 /* Extracting the function address from a pmf is only
2573 allowed with -Wno-pmf-conversions. It only works for
2574 pmf constants. */
2578 }
2579 else
2580 {
2583 }
2584 }
2592 /* Start by extracting all the information from the PMF itself. */
2597 {
2610 }
2612 /* Convert down to the right base before using the instance. First
2613 use the type... */
2620 /* ...and then the delta in the PMF. */
2624 /* Hand back the adjusted 'this' argument to our caller. */
2627 /* Next extract the vtable pointer from the object. */
2629 instance_ptr);
2632 /* Finally, extract the function pointer from the vtable. */
2637 /* When using function descriptors, the address of the
2638 vtable entry is treated as a function pointer. */
2646 /* Make sure this doesn't get evaluated first inside one of the
2647 branches of the COND_EXPR. */
2653 }
2655 }
2657 tree
2661 {
2665 tree result;
2670 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2671 Strip such NOP_EXPRs, since FUNCTION is used in non-lvalue context. */
2677 {
2684 /* Convert anything with function type to a pointer-to-function. */
2688 /* Differs from default_conversion by not setting TREE_ADDRESSABLE
2689 (because calling an inline function does not mean the function
2690 needs to be separately compiled). */
2694 else
2696 }
2697 else
2698 {
2702 }
2710 {
2712 original);
2714 }
2721 || is_method
2723 {
2726 }
2728 /* fntype now gets the type of function pointed to. */
2731 /* Convert the parameters to the types declared in the
2732 function prototype, or apply default promotions. */
2737 else
2742 {
2745 else
2747 }
2749 /* Check for errors in format strings. */
2754 /* Recognize certain built-in functions so we can make tree-codes
2755 other than CALL_EXPR. We do this when it enables fold-const.c
2756 to do something useful. */
2761 {
2766 }
2768 /* Some built-in function calls will be evaluated at
2769 compile-time in fold (). */
2774 {
2778 }
2782 }
2784 tree
2787 {
2789 }
2790 \f
2791 /* Convert the actual parameter expressions in the list VALUES
2792 to the types in the list TYPELIST.
2793 If parmdecls is exhausted, or when an element has NULL as its type,
2794 perform the default conversions.
2796 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages.
2798 This is also where warnings about wrong number of args are generated.
2800 Return a list of expressions for the parameters as converted.
2802 Both VALUES and the returned value are chains of TREE_LIST nodes
2803 with the elements of the list in the TREE_VALUE slots of those nodes.
2805 In C++, unspecified trailing parameters can be filled in with their
2806 default arguments, if such were specified. Do so here. */
2808 tree
2812 {
2818 /* Argument passing is always copy-initialization. */
2822 {
2824 {
2828 else
2830 }
2831 else
2833 }
2836 valtail;
2838 {
2846 {
2848 {
2850 fndecl);
2852 }
2853 else
2855 /* In case anybody wants to know if this argument
2856 list is valid. */
2860 }
2865 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
2866 Strip such NOP_EXPRs, since VAL is used in non-lvalue context. */
2873 {
2878 }
2884 {
2885 /* Formal parm type is specified by a function prototype. */
2886 tree parmval;
2889 {
2892 }
2893 else
2894 {
2895 parmval = convert_for_initialization
2899 }
2905 }
2906 else
2907 {
2913 /* Don't do ellipsis conversion for __built_in_constant_p
2914 as this will result in spurious warnings for non-POD
2915 types. */
2917 else
2921 }
2925 }
2928 {
2929 /* See if there are default arguments that can be used */
2932 {
2934 {
2935 tree parmval
2945 /* ends with `...'. */
2948 }
2949 }
2950 else
2951 {
2953 {
2957 }
2958 else
2961 }
2962 }
2965 }
2966 \f
2967 /* Build a binary-operation expression, after performing default
2968 conversions on the operands. CODE is the kind of expression to build. */
2970 tree
2974 {
2979 }
2981 #if 0
2983 tree
2985 {
2986 tree type;
2988 /* If any of the operands is erroneous the result is erroneous too. */
2997 /* If at least one operand has a dependent type, we cannot
2998 determine the type of the expression until instantiation time. */
3000 else
3001 {
3003 tree op0_type;
3004 tree op1_type;
3005 tree op2_type;
3007 /* None of the operands is dependent, so we can compute the type
3008 of the expression at this point. We must compute the type so
3009 that in things like:
3011 template <int I>
3012 void f() { S<sizeof(I + 3)> s; ... }
3014 we can tell that the type of "s" is non-dependent.
3016 If we're processing a template argument, we do not want to
3017 actually change the operands in any way. Adding conversions,
3018 performing constant folding, etc., would all change mangled
3019 names. For example, in:
3021 template <int I>
3022 void f(S<sizeof(3 + 4 + I)>);
3024 we need to determine that "3 + 4 + I" has type "int", without
3025 actually turning the expression into "7 + I". */
3028 /* If an overloaded operator was found, the expression will
3029 have the type returned by the function. */
3031 else
3032 {
3033 /* There is no overloaded operator so we can just use the
3034 default rules for determining the type of the operand. */
3041 {
3043 /* [expr.ass]
3045 The result of the assignment operation is the value
3046 stored in the left operand. */
3050 /* Implement this case. */
3054 /* [expr.post.incr]
3056 The type of the result is the cv-unqualified version
3057 of the type of the operand. */
3062 /* [expr.pre.incr]
3064 The value is the new value of the operand. */
3068 /* [expr.unary.op]
3070 If the type of the expression is "pointer to T", the
3071 type of the result is "T". */
3075 /* [expr.unary.op]
3077 If the type of the expression is "T", the type of the
3078 result is "pointer to T". */
3079 /* FIXME: Handle the pointer-to-member case. */
3082 /* FIXME: Implement this case. */
3086 /* [expr.shift]
3088 The type of the result is that of the promoted left
3089 operand. */
3093 /* FIXME: Be careful of special pointer-arithmetic
3094 cases. */
3095 /* Fall through. */
3098 /* These are GNU extensions; the result type is computed
3099 as it would be for other arithmetic operators. */
3100 /* Fall through. */
3107 /* [expr.bit.and], [expr.xor], [expr.or], [expr.mul]
3109 The usual arithmetic conversions are performed on the
3110 operands and determine the type of the result. */
3111 /* FIXME: Check that this is possible. */
3120 /* [expr.rel]
3122 The type of the result is bool. */
3127 /* [expr.log.and], [expr.log.org]
3129 The result is a bool. */
3133 /* FIXME: Handle special rules for conditioanl
3134 expressions. */
3141 }
3142 /* If the type of the expression could not be determined,
3143 something is wrong. */
3146 /* If the type is erroneous, the expression is erroneous
3147 too. */
3150 }
3151 }
3154 }
3156 #endif
3158 /* Build a binary-operation expression without default conversions.
3159 CODE is the kind of expression to build.
3160 This function differs from `build' in several ways:
3161 the data type of the result is computed and recorded in it,
3162 warnings are generated if arg data types are invalid,
3163 special handling for addition and subtraction of pointers is known,
3164 and some optimization is done (operations on narrow ints
3165 are done in the narrower type when that gives the same result).
3166 Constant folding is also done before the result is returned.
3168 Note that the operands will never have enumeral types
3169 because either they have just had the default conversions performed
3170 or they have both just been converted to some other type in which
3171 the arithmetic is to be done.
3173 C++: must do special pointer arithmetic when implementing
3174 multiple inheritance, and deal with pointer to member functions. */
3176 tree
3181 {
3186 /* Expression code to give to the expression when it is built.
3187 Normally this is CODE, which is what the caller asked for,
3188 but in some special cases we change it. */
3191 /* Data type in which the computation is to be performed.
3192 In the simplest cases this is the common type of the arguments. */
3195 /* Nonzero means operands have already been type-converted
3196 in whatever way is necessary.
3197 Zero means they need to be converted to RESULT_TYPE. */
3200 /* Nonzero means create the expression with this type, rather than
3201 RESULT_TYPE. */
3204 /* Nonzero means after finally constructing the expression
3205 convert it to this type. */
3208 /* Nonzero if this is an operation like MIN or MAX which can
3209 safely be computed in short if both args are promoted shorts.
3210 Also implies COMMON.
3211 -1 indicates a bitwise operation; this makes a difference
3212 in the exact conditions for when it is safe to do the operation
3213 in a narrower mode. */
3216 /* Nonzero if this is a comparison operation;
3217 if both args are promoted shorts, compare the original shorts.
3218 Also implies COMMON. */
3221 /* Nonzero if this is a right-shift operation, which can be computed on the
3222 original short and then promoted if the operand is a promoted short. */
3225 /* Nonzero means set RESULT_TYPE to the common type of the args. */
3228 /* Apply default conversions. */
3235 {
3240 }
3241 else
3242 {
3247 }
3249 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
3253 /* DTRT if one side is an overloaded function, but complain about it. */
3255 {
3258 {
3262 }
3263 }
3265 {
3268 {
3272 }
3273 }
3278 /* The expression codes of the data types of the arguments tell us
3279 whether the arguments are integers, floating, pointers, etc. */
3283 /* If an error was already reported for one of the arguments,
3284 avoid reporting another error. */
3290 {
3292 /* Handle the pointer + int case. */
3297 else
3302 /* Subtraction of two similar pointers.
3303 We must subtract them as integers, then divide by object size. */
3307 /* Handle pointer minus int. Just like pointer plus int. */
3310 else
3327 {
3335 else
3336 /* When dividing two signed integers, we have to promote to int.
3337 unless we divide by a constant != -1. Note that default
3338 conversion will have been performed on the operands at this
3339 point, so we have to dig out the original type to find out if
3340 it was unsigned. */
3347 }
3366 {
3367 /* Although it would be tempting to shorten always here, that loses
3368 on some targets, since the modulo instruction is undefined if the
3369 quotient can't be represented in the computation mode. We shorten
3370 only if unsigned or if dividing by something we know != -1. */
3376 }
3386 /* Shift operations: result has same type as first operand;
3387 always convert second operand to int.
3388 Also set SHORT_SHIFT if shifting rightward. */
3392 {
3395 {
3398 else
3399 {
3404 }
3405 }
3406 /* Convert the shift-count to an integer, regardless of
3407 size of value being shifted. */
3410 /* Avoid converting op1 to result_type later. */
3412 }
3417 {
3420 {
3425 }
3426 /* Convert the shift-count to an integer, regardless of
3427 size of value being shifted. */
3430 /* Avoid converting op1 to result_type later. */
3432 }
3438 {
3441 {
3448 }
3449 /* Convert the shift-count to an integer, regardless of
3450 size of value being shifted. */
3453 }
3475 {
3478 }
3480 {
3483 }
3485 {
3489 }
3494 {
3495 /* E will be the final comparison. */
3496 tree e;
3497 /* E1 and E2 are for scratch. */
3498 tree e1;
3499 tree e2;
3500 tree pfn0;
3501 tree pfn1;
3502 tree delta0;
3503 tree delta1;
3510 /* We generate:
3512 (op0.pfn == op1.pfn
3513 && (!op0.pfn || op0.delta == op1.delta))
3515 The reason for the `!op0.pfn' bit is that a NULL
3516 pointer-to-member is any member with a zero PFN; the
3517 DELTA field is unspecified. */
3521 delta_identifier);
3523 delta_identifier);
3526 pfn0,
3528 integer_zero_node));
3535 }
3571 {
3574 }
3576 {
3579 }
3591 {
3594 }
3600 }
3603 &&
3605 {
3611 /* For certain operations (which identify themselves by shorten != 0)
3612 if both args were extended from the same smaller type,
3613 do the arithmetic in that type and then extend.
3615 shorten !=0 and !=1 indicates a bitwise operation.
3616 For them, this optimization is safe only if
3617 both args are zero-extended or both are sign-extended.
3618 Otherwise, we might change the result.
3619 Eg, (short)-1 | (unsigned short)-1 is (int)-1
3620 but calculated in (unsigned short) it would be (unsigned short)-1. */
3623 {
3627 /* UNS is 1 if the operation to be done is an unsigned one. */
3629 tree type;
3633 /* Handle the case that OP0 does not *contain* a conversion
3634 but it *requires* conversion to FINAL_TYPE. */
3641 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */
3643 /* For bitwise operations, signedness of nominal type
3644 does not matter. Consider only how operands were extended. */
3648 /* Note that in all three cases below we refrain from optimizing
3649 an unsigned operation on sign-extended args.
3650 That would not be valid. */
3652 /* Both args variable: if both extended in same way
3653 from same width, do it in that width.
3654 Do it unsigned if args were zero-extended. */
3661 result_type = c_common_signed_or_unsigned_type
3679 }
3681 /* Shifts can be shortened if shifting right. */
3684 {
3694 /* We can shorten only if the shift count is less than the
3695 number of bits in the smaller type size. */
3697 /* If arg is sign-extended and then unsigned-shifted,
3698 we can simulate this with a signed shift in arg's type
3699 only if the extended result is at least twice as wide
3700 as the arg. Otherwise, the shift could use up all the
3701 ones made by sign-extension and bring in zeros.
3702 We can't optimize that case at all, but in most machines
3703 it never happens because available widths are 2**N. */
3705 || unsigned_arg
3708 {
3709 /* Do an unsigned shift if the operand was zero-extended. */
3710 result_type
3713 /* Convert value-to-be-shifted to that type. */
3717 }
3718 }
3720 /* Comparison operations are shortened too but differently.
3721 They identify themselves by setting short_compare = 1. */
3724 {
3725 /* Don't write &op0, etc., because that would prevent op0
3726 from being kept in a register.
3727 Instead, make copies of the our local variables and
3728 pass the copies by reference, then copy them back afterward. */
3731 tree val
3738 }
3742 {
3750 /* Check for comparison of different enum types. */
3755 {
3758 }
3760 /* Give warnings for comparisons between signed and unsigned
3761 quantities that may fail. */
3762 /* Do the checking based on the original operand trees, so that
3763 casts will be considered, but default promotions won't be. */
3765 /* Do not warn if the comparison is being done in a signed type,
3766 since the signed type will only be chosen if it can represent
3767 all the values of the unsigned type. */
3770 /* Do not warn if both operands are unsigned. */
3773 /* Do not warn if the signed quantity is an unsuffixed
3774 integer literal (or some static constant expression
3775 involving such literals or a conditional expression
3776 involving such literals) and it is non-negative. */
3780 /* Do not warn if the comparison is an equality operation,
3781 the unsigned quantity is an integral constant and it does
3782 not use the most significant bit of result_type. */
3791 else
3794 /* Warn if two unsigned values are being compared in a size
3795 larger than their original size, and one (and only one) is the
3796 result of a `~' operator. This comparison will always fail.
3798 Also warn if one operand is a constant, and the constant does not
3799 have all bits set that are set in the ~ operand when it is
3800 extended. */
3804 {
3811 {
3812 tree primop;
3818 {
3822 }
3823 else
3824 {
3828 }
3833 {
3837 }
3838 }
3845 }
3846 }
3847 }
3849 /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
3850 If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
3851 Then the expression will be built.
3852 It will be given type FINAL_TYPE if that is nonzero;
3853 otherwise, it will be given type RESULT_TYPE. */
3856 {
3860 }
3862 /* Issue warnings about peculiar, but valid, uses of NULL. */
3864 and ||, so NULL is no exception. */
3869 /* Or vice versa. */
3872 /* Or, both are NULL and the operation was not a comparison. */
3875 /* Some sort of arithmetic operation involving NULL was
3876 performed. Note that pointer-difference and pointer-addition
3877 have already been handled above, and so we don't end up here in
3878 that case. */
3882 {
3890 }
3895 {
3905 }
3906 }
3907 \f
3908 /* Return a tree for the sum or difference (RESULTCODE says which)
3909 of pointer PTROP and integer INTOP. */
3911 static tree
3915 {
3918 /* pointer_int_sum() uses size_in_bytes() on the TREE_TYPE(res_type)
3919 in certain circumstance (when it's valid to do so). So we need
3920 to make sure it's complete. We don't need to check here, if we
3921 can actually complete it at all, as those checks will be done in
3922 pointer_int_sum() anyway. */
3926 }
3928 /* Return a tree for the difference of pointers OP0 and OP1.
3929 The resulting tree has type int. */
3931 static tree
3935 {
3944 {
3953 }
3955 /* First do the subtraction as integers;
3956 then drop through to build the divide operator. */
3962 /* This generates an error if op1 is a pointer to an incomplete type. */
3970 ? integer_one_node
3973 /* Do the division. */
3981 }
3982 \f
3983 /* Construct and perhaps optimize a tree representation
3984 for a unary operation. CODE, a tree_code, specifies the operation
3985 and XARG is the operand. */
3987 tree
3990 tree xarg;
3991 {
3992 tree exp;
3998 /* & rec, on incomplete RECORD_TYPEs is the simple opr &, not an
3999 error message. */
4006 else
4007 {
4008 tree rval;
4014 }
4016 {
4017 /* A pointer to member-function can be formed only by saying
4018 &X::mf. */
4021 {
4023 {
4025 xarg);
4027 }
4028 else
4029 {
4031 xarg);
4033 }
4034 }
4037 {
4042 {
4043 /* A single non-static member, make sure we don't allow a
4044 pointer-to-member. */
4049 }
4051 }
4054 }
4060 }
4062 /* Like c_common_truthvalue_conversion, but handle pointer-to-member
4063 constants, where a null value is represented by an INTEGER_CST of
4064 -1. */
4066 tree
4068 tree expr;
4069 {
4073 else
4075 }
4077 /* Just like cp_truthvalue_conversion, but we want a CLEANUP_POINT_EXPR. */
4079 tree
4081 tree expr;
4082 {
4083 tree t;
4091 }
4093 /* C++: Must handle pointers to members.
4095 Perhaps type instantiation should be extended to handle conversion
4096 from aggregates to types we don't yet know we want? (Or are those
4097 cases typically errors which should be reported?)
4099 NOCONVERT nonzero suppresses the default promotions
4100 (such as from short to int). */
4102 tree
4105 tree xarg;
4107 {
4108 /* No default_conversion here. It causes trouble for ADDR_EXPR. */
4112 tree val;
4118 {
4120 /* This is used for unary plus, because a CONVERT_EXPR
4121 is enough to prevent anybody from looking inside for
4122 associativity, but won't generate any code. */
4126 else
4127 {
4132 }
4144 {
4148 }
4164 /* Conjugating a real value is a no-op, but allow it anyway. */
4187 else
4195 else
4202 /* Handle complex lvalues (when permitted)
4203 by reduction to simpler cases. */
4209 /* Increment or decrement the real part of the value,
4210 and don't change the imaginary part. */
4212 {
4220 }
4222 /* Report invalid types. */
4226 {
4233 else
4236 }
4238 /* Report something read-only. */
4247 {
4254 /* ARM $5.2.5 last annotation says this should be forbidden. */
4260 /* Compute the increment. */
4263 {
4280 }
4281 else
4286 /* Handle incrementing a cast-expression. */
4289 {
4297 {
4304 else
4314 /* Eliminate warning about unused result of + or -. */
4317 }
4321 }
4323 /* Complain about anything else that is not a true lvalue. */
4329 /* Forbid using -- on `bool'. */
4331 {
4333 {
4336 }
4337 #if 0
4338 /* This will only work if someone can convince Kenner to accept
4339 my patch to expand_increment. (jason) */
4341 #else
4343 #endif
4344 }
4345 else
4350 }
4353 /* Note that this operation never does default_conversion
4354 regardless of NOCONVERT. */
4358 {
4359 arg = build1
4364 }
4366 /* ARM $3.4 */
4369 /* Let &* cancel out to simplify resulting code. */
4371 {
4372 /* We don't need to have `current_class_ptr' wrapped in a
4373 NON_LVALUE_EXPR node. */
4379 {
4380 arg = build1
4384 }
4386 /* Don't let this be an lvalue. */
4389 }
4391 /* For &x[y], return x+y */
4393 {
4398 }
4400 /* Uninstantiated types are all functions. Taking the
4401 address of a function is a no-op, so just return the
4402 argument. */
4406 {
4408 /* We don't know the type yet, so just work around the problem.
4409 We know that this will resolve to an lvalue. */
4411 }
4415 {
4416 /* They're trying to take the address of a unique non-static
4417 member function. This is ill-formed (except in MS-land),
4418 but let's try to DTRT.
4419 Note: We only handle unique functions here because we don't
4420 want to complain if there's a static overload; non-unique
4421 cases will be handled by instantiate_type. But we need to
4422 handle this case here to allow casts on the resulting PMF.
4423 We could defer this in non-MS mode, but it's easier to give
4424 a useful error here. */
4430 {
4433 /* An expression like &memfn. */
4434 pedwarn ("ISO C++ forbids taking the address of an unqualified or parenthesized non-static member function to form a pointer to member function. Say `&%T::%D'", base, name);
4435 else
4436 pedwarn ("ISO C++ forbids taking the address of a bound member function to form a pointer to member function. Say `&%T::%D'", base, name);
4437 }
4439 }
4444 /* Handle complex lvalues (when permitted)
4445 by reduction to simpler cases. */
4451 {
4465 }
4467 /* Allow the address of a constructor if all the elements
4468 are constant. */
4471 ;
4472 /* Anything not already handled and not a true memory reference
4473 is an error. */
4485 {
4486 tree addr;
4494 {
4498 }
4503 {
4504 /* offsetof idiom, fold it. */
4516 }
4517 else
4520 /* Address of a static or external variable or
4521 function counts as a constant */
4527 {
4530 }
4533 }
4537 }
4540 {
4544 }
4548 }
4550 /* Apply unary lvalue-demanding operator CODE to the expression ARG
4551 for certain kinds of expressions which are not really lvalues
4552 but which we can accept as lvalues.
4554 If ARG is not a kind of expression we can handle, return zero. */
4556 tree
4559 tree arg;
4560 {
4561 /* Handle (a, b) used as an "lvalue". */
4563 {
4567 }
4569 /* Handle (a ? b : c) used as an "lvalue". */
4574 /* Handle (a = b), (++a), and (--a) used as an "lvalue". */
4578 {
4581 {
4585 }
4586 return unary_complex_lvalue
4588 }
4593 /* Handle (a = b) used as an "lvalue" for `&'. */
4596 {
4601 }
4606 {
4607 /* The representation of something of type OFFSET_TYPE
4608 is really the representation of a pointer to it.
4609 Here give the representation its true type. */
4610 tree t;
4619 /* Check all this code for right semantics. */
4621 {
4625 }
4628 else
4629 {
4630 tree type;
4635 {
4638 }
4640 {
4641 /* This cannot form a pointer to method, so we must
4642 resolve the offset ref, and take the address of the
4643 result. For instance,
4644 &(C::m) */
4648 }
4651 {
4654 }
4659 }
4660 }
4663 /* We permit compiler to make function calls returning
4664 objects of aggregate type look like lvalues. */
4665 {
4672 {
4675 else
4678 }
4683 }
4685 /* Don't let anything else be handled specially. */
4687 }
4688 \f
4689 /* Mark EXP saying that we need to be able to take the
4690 address of it; it should not be allocated in a register.
4691 Value is true if successful.
4693 C++: we do not allow `current_class_ptr' to be addressable. */
4695 bool
4697 tree exp;
4698 {
4703 {
4714 {
4718 }
4719 /* FALLTHRU */
4722 /* Caller should not be trying to mark initialized
4723 constant fields addressable. */
4728 /* FALLTHRU */
4735 x);
4756 }
4757 }
4758 \f
4759 /* Build and return a conditional expression IFEXP ? OP1 : OP2. */
4761 tree
4764 {
4769 }
4770 \f
4771 /* Handle overloading of the ',' operator when needed. Otherwise,
4772 this function just builds an expression list. */
4774 tree
4776 tree list;
4777 {
4779 tree result;
4794 {
4795 /* FIXME: This test should be in the implicit cast to void of the LHS. */
4796 /* the left-hand operand of a comma expression is like an expression
4797 statement: we should warn if it doesn't have any side-effects,
4798 unless it was explicitly cast to (void). */
4803 }
4807 #endif
4809 return build_compound_expr
4813 }
4815 /* Given a list of expressions, return a compound expression
4816 that performs them all and returns the value of the last of them. */
4818 tree
4820 tree list;
4821 {
4823 tree first;
4828 {
4829 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4830 Strip such NOP_EXPRs, since LIST is used in non-lvalue context. */
4836 }
4847 /* When pedantic, a compound expression cannot be a constant expression. */
4852 }
4854 tree
4857 {
4858 tree intype;
4868 {
4871 }
4873 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4874 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4881 {
4884 }
4899 /* FIXME handle casting to array type. */
4906 /* This is a standard conversion. */
4909 {
4910 /* They're pointers to objects. They must be aggregates that
4911 are related non-virtually. */
4912 base_kind kind;
4919 }
4921 {
4922 /* They're pointers to members. The pointed to objects must be
4923 the same (ignoring CV qualifiers), and the containing classes
4924 must be related non-virtually. */
4925 base_kind kind;
4935 }
4943 /* DR 128: "A value of integral _or enumeration_ type can be explicitly
4944 converted to an enumeration type."
4945 The integral to enumeration will be accepted by the previous clause.
4946 We need to explicitly check for enumeration to enumeration. */
4949 /* [expr.static.cast]
4951 The static_cast operator shall not be used to cast away
4952 constness. */
4954 {
4958 }
4965 }
4967 tree
4970 {
4971 tree intype;
4980 {
4983 }
4986 {
4989 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
4990 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
4994 }
4999 {
5001 {
5002 error ("invalid reinterpret_cast of an rvalue expression of type `%T' to type `%T'", intype, type);
5004 }
5007 expr = build_reinterpret_cast
5012 }
5020 {
5024 }
5027 {
5030 }
5033 {
5040 }
5043 {
5047 }
5048 else
5049 {
5053 }
5056 }
5058 tree
5061 {
5062 tree intype;
5071 {
5074 }
5077 error ("invalid use of const_cast with type `%T', which is not a pointer, reference, nor a pointer-to-data-member type", type);
5079 {
5080 error ("invalid use of const_cast with type `%T', which is a pointer or reference to a function type", type);
5082 }
5085 {
5088 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5089 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5093 }
5100 {
5102 {
5105 }
5108 {
5112 }
5113 }
5121 }
5123 /* Build an expression representing a cast to type TYPE of expression EXPR.
5125 ALLOW_NONCONVERTING is true if we should allow non-converting constructors
5126 when doing the cast. */
5128 tree
5131 {
5133 tree otype;
5139 {
5143 }
5145 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
5146 Strip such NOP_EXPRs if VALUE is being used in non-lvalue context. */
5156 {
5157 /* Allow casting from T1* to T2[] because Cfront allows it.
5158 NIHCL uses it. It is not valid ISO C++ however. */
5160 {
5163 }
5164 else
5165 {
5168 }
5169 }
5173 {
5176 }
5179 {
5180 /* Conversion to void does not cause any of the normal function to
5181 * pointer, array to pointer and lvalue to rvalue decays. */
5185 }
5186 /* Convert functions and arrays to pointers and
5187 convert references to their expanded types,
5188 but don't convert any other types. If, however, we are
5189 casting to a class type, there's no reason to do this: the
5190 cast will only succeed if there is a converting constructor,
5191 and the default conversions will be done at that point. In
5192 fact, doing the default conversion here is actually harmful
5193 in cases like this:
5195 typedef int A[2];
5196 struct S { S(const A&); };
5198 since we don't want the array-to-pointer conversion done. */
5200 {
5203 /* Don't do the default conversion on a ->* expression. */
5209 }
5211 /* However, even for class types, we still need to strip away
5212 the reference type, since the call to convert_force below
5213 does not expect the input expression to be of reference
5214 type. */
5219 /* Optionally warn about potentially worrisome casts. */
5237 /* Don't warn about converting any constant. */
5242 value = (convert_from_reference
5245 else
5246 {
5247 tree ovalue;
5254 /* Ignore any integer overflow caused by the cast. */
5256 {
5259 }
5260 }
5262 /* Warn about possible alignment problems. Do this here when we will have
5263 instantiated any necessary template types. */
5275 /* Always produce some operator for an explicit cast,
5276 so we can tell (for -pedantic) that the cast is no lvalue. */
5282 }
5283 \f
5284 /* Build an assignment expression of lvalue LHS from value RHS.
5285 MODIFYCODE is the code for a binary operator that we use
5286 to combine the old value of LHS with RHS to get the new value.
5287 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.
5289 C++: If MODIFYCODE is INIT_EXPR, then leave references unbashed. */
5291 tree
5293 tree lhs;
5295 tree rhs;
5296 {
5303 /* Avoid duplicate error messages from operands that had errors. */
5307 /* Handle control structure constructs used as "lvalues". */
5309 {
5310 /* Handle --foo = 5; as these are valid constructs in C++ */
5318 lhs,
5322 /* Handle (a, b) used as an "lvalue". */
5337 /* Handle (a ? b : c) used as an "lvalue". */
5339 {
5340 /* Produce (a ? (b = rhs) : (c = rhs))
5341 except that the RHS goes through a save-expr
5342 so the code to compute it is only emitted once. */
5343 tree cond;
5348 /* Check this here to avoid odd errors when trying to convert
5349 a throw to the type of the COND_EXPR. */
5353 cond = build_conditional_expr
5364 /* Make sure the code to compute the rhs comes out
5365 before the split. */
5367 }
5377 }
5380 {
5382 {
5388 }
5391 else
5392 {
5396 LOOKUP_NORMAL);
5400 }
5401 }
5402 else
5403 {
5405 {
5408 }
5414 {
5415 /* `operator=' is not an inheritable operator. */
5418 else
5419 {
5425 }
5427 }
5428 else
5429 {
5430 /* A binary op has been requested. Combine the old LHS
5431 value with the RHS producing the value we should actually
5432 store into the LHS. */
5439 {
5443 }
5445 /* Now it looks like a plain assignment. */
5447 }
5451 }
5453 /* Handle a cast used as an "lvalue".
5454 We have already performed any binary operator using the value as cast.
5455 Now convert the result to the cast type of the lhs,
5456 and then true type of the lhs and store it there;
5457 then convert result back to the cast type to be the value
5458 of the assignment. */
5461 {
5469 {
5471 tree result;
5479 /* ISO C++ 5.4/1: The result is an lvalue if T is a reference
5480 type, otherwise the result is an rvalue. */
5490 }
5494 }
5496 /* Now we have handled acceptable kinds of LHS that are not truly lvalues.
5497 Reject anything strange now. */
5502 /* Warn about modifying something that is `const'. Don't warn if
5503 this is initialization. */
5506 /* Functions are not modifiable, even though they are
5507 lvalues. */
5510 /* If it's an aggregate and any field is const, then it is
5511 effectively const. */
5516 /* If storing into a structure or union member, it has probably been
5517 given type `int'. Compute the type that would go with the actual
5518 amount of storage the member occupies. */
5524 {
5527 /* If storing in a field that is in actuality a short or narrower
5528 than one, we must store in the field in its actual type. */
5531 {
5534 }
5535 }
5538 {
5543 }
5545 /* Convert new value to destination type. */
5548 {
5553 {
5557 }
5559 /* Allow array assignment in compiler-generated code. */
5566 }
5571 else
5572 {
5573 /* Avoid warnings on enum bit fields. */
5576 {
5580 }
5581 else
5588 /* Can't initialize directly from a TARGET_EXPR, since that would
5589 cause the lhs to be constructed twice, and possibly result in
5590 accidental self-initialization. So we force the TARGET_EXPR to be
5591 expanded without a target. */
5595 }
5601 {
5602 tree lhs1;
5610 /* Cannot have two identical lhs on this one tree (result) as preexpand
5611 calls will rip them out and fill in RTL for them, but when the
5612 rtl is generated, the calls will only be in the first side of the
5613 condition, not on both, or before the conditional jump! (mrs) */
5617 /* If there's no change, the COND_EXPR behaves like any other rhs. */
5620 else
5621 {
5623 /* We have to convert each arm to the proper type because the
5624 types may have been munged by constant folding. */
5625 result
5633 }
5634 }
5635 else
5641 /* If we got the LHS in a different type for storing in,
5642 convert the result back to the nominal type of LHS
5643 so that the value we return always has the same type
5644 as the LHS argument. */
5648 /* Avoid warnings converting integral types back into enums
5649 for enum bit fields. */
5652 {
5656 }
5659 }
5661 tree
5663 tree lhs;
5665 tree rhs;
5666 {
5672 {
5677 }
5679 }
5681 \f
5682 /* Get difference in deltas for different pointer to member function
5683 types. Return integer_zero_node, if FROM cannot be converted to a
5684 TO type. If FORCE is true, then allow reverse conversions as well.
5686 Note that the naming of FROM and TO is kind of backwards; the return
5687 value is what we add to a TO in order to get a FROM. They are named
5688 this way because we call this function to find out how to convert from
5689 a pointer to member of FROM to a pointer to member of TO. */
5691 static tree
5695 {
5697 tree binfo;
5698 tree virt_binfo;
5699 base_kind kind;
5703 {
5706 }
5708 {
5710 {
5714 }
5721 {
5722 /* This is a reinterpret cast, we choose to do nothing. */
5726 }
5730 integer_zero_node,
5731 delta);
5734 }
5738 {
5739 /* This is a reinterpret cast, we choose to do nothing. */
5743 else
5747 }
5751 }
5753 /* Return a constructor for the pointer-to-member-function TYPE using
5754 the other components as specified. */
5756 tree
5759 {
5761 tree delta_field;
5762 tree pfn_field;
5764 /* Pull the FIELD_DECLs out of the type. */
5768 /* Make sure DELTA has the type we want. */
5771 /* Finish creating the initializer. */
5782 }
5784 /* Build a constructor for a pointer to member function. It can be
5785 used to initialize global variables, local variable, or used
5786 as a value in expressions. TYPE is the POINTER to METHOD_TYPE we
5787 want to be.
5789 If FORCE is nonzero, then force this conversion, even if
5790 we would rather not do it. Usually set when using an explicit
5791 cast.
5793 Return error_mark_node, if something goes wrong. */
5795 tree
5799 {
5800 tree fn;
5804 /* Handle multiple conversions of pointer to member functions. */
5806 {
5809 tree n;
5818 force);
5820 /* We don't have to do any conversion to convert a
5821 pointer-to-member to its own type. But, we don't want to
5822 just return a PTRMEM_CST if there's an explicit cast; that
5823 cast should make the expression an invalid template argument. */
5825 {
5830 }
5835 /* Obtain the function pointer and the current DELTA. */
5838 else
5839 {
5842 }
5844 /* Just adjust the DELTA field. */
5850 }
5852 /* Handle null pointer to member function conversions. */
5854 {
5857 integer_zero_node,
5858 pfn);
5859 }
5867 }
5869 /* Return the DELTA, IDX, PFN, and DELTA2 values for the PTRMEM_CST
5870 given by CST.
5872 ??? There is no consistency as to the types returned for the above
5873 values. Some code acts as if its a sizetype and some as if its
5874 integer_type_node. */
5876 void
5878 tree cst;
5881 {
5888 /* The class that the function belongs to. */
5891 /* The class that we're creating a pointer to member of. */
5894 /* First, calculate the adjustment to the function's class. */
5899 else
5900 {
5901 /* If we're dealing with a virtual function, we have to adjust 'this'
5902 again, to point to the base which provides the vtable entry for
5903 fn; the call will do the opposite adjustment. */
5909 /* We set PFN to the vtable offset at which the function can be
5910 found, plus one (unless ptrmemfunc_vbit_in_delta, in which
5911 case delta is shifted left, and then incremented). */
5917 {
5920 integer_one_node));
5932 }
5936 }
5937 }
5939 /* Return an expression for PFN from the pointer-to-member function
5940 given by T. */
5942 tree
5944 tree t;
5945 {
5947 {
5948 tree delta;
5949 tree pfn;
5954 }
5957 }
5959 /* Expression EXPR is about to be implicitly converted to TYPE. Warn
5960 if this is a potentially dangerous thing to do. Returns a possibly
5961 marked EXPR. */
5963 tree
5965 tree type;
5966 tree expr;
5968 tree fndecl;
5970 {
5974 /* Issue warnings about peculiar, but valid, uses of NULL. */
5976 {
5980 else
5982 }
5984 /* Warn about assigning a floating-point type to an integer type. */
5987 {
5991 else
5993 }
5994 /* And warn about assigning a negative value to an unsigned
5995 variable. */
5997 {
6000 {
6004 else
6007 }
6013 }
6015 }
6017 /* Convert value RHS to type TYPE as preparation for an assignment to
6018 an lvalue of type TYPE. ERRTYPE is a string to use in error
6019 messages: "assignment", "return", etc. If FNDECL is non-NULL, we
6020 are doing the conversion in order to pass the PARMNUMth argument of
6021 FNDECL. */
6023 static tree
6027 tree fndecl;
6029 {
6040 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
6054 /* The RHS of an assignment cannot have void type. */
6056 {
6059 }
6061 /* Simplify the RHS if possible. */
6065 /* We do not use decl_constant_value here because of this case:
6067 const char* const s = "s";
6069 The conversion rules for a string literal are more lax than for a
6070 variable; in particular, a string literal can be converted to a
6071 "char *" but the variable "s" cannot be converted in the same
6072 way. If the conversion is allowed, the optimization should be
6073 performed while creating the converted expression. */
6075 /* [expr.ass]
6077 The expression is implicitly converted (clause _conv_) to the
6078 cv-unqualified type of the left operand.
6080 We allow bad conversions here because by the time we get to this point
6081 we are committed to doing the conversion. If we end up doing a bad
6082 conversion, convert_like will complain. */
6084 {
6085 /* When -Wno-pmf-conversions is use, we just silently allow
6086 conversions from pointers-to-members to plain pointers. If
6087 the conversion doesn't work, cp_convert will complain. */
6092 else
6093 {
6094 /* If the right-hand side has unknown type, then it is an
6095 overloaded function. Call instantiate_type to get error
6096 messages. */
6102 else
6104 errtype);
6106 }
6107 }
6109 }
6111 /* Convert RHS to be of type TYPE.
6112 If EXP is nonzero, it is the target of the initialization.
6113 ERRTYPE is a string to use in error messages.
6115 Two major differences between the behavior of
6116 `convert_for_assignment' and `convert_for_initialization'
6117 are that references are bashed in the former, while
6118 copied in the latter, and aggregates are assigned in
6119 the former (operator=) while initialized in the
6120 latter (X(X&)).
6122 If using constructor make sure no conversion operator exists, if one does
6123 exist, an ambiguity exists.
6125 If flags doesn't include LOOKUP_COMPLAIN, don't complain about anything. */
6127 tree
6132 tree fndecl;
6134 {
6139 /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
6140 Strip such NOP_EXPRs, since RHS is used in non-lvalue context. */
6151 {
6155 }
6176 /* We accept references to incomplete types, so we can
6177 return here before checking if RHS is of complete type. */
6180 {
6181 /* This should eventually happen in convert_arguments. */
6188 {
6193 }
6195 }
6211 }
6212 \f
6213 /* Expand an ASM statement with operands, handling output operands
6214 that are not variables or INDIRECT_REFS by transforming such
6215 cases into cases that expand_asm_operands can handle.
6217 Arguments are same as for expand_asm_operands.
6219 We don't do default conversions on all inputs, because it can screw
6220 up operands that are expected to be in memory. */
6222 void
6228 {
6231 /* o[I] is the place that output number I should be written. */
6235 /* Record the contents of OUTPUTS before it is modified. */
6239 /* Generate the ASM_OPERANDS insn;
6240 store into the TREE_VALUEs of OUTPUTS some trees for
6241 where the values were actually stored. */
6244 /* Copy all the intermediate outputs into the specified outputs. */
6246 {
6248 {
6253 /* Restore the original value so that it's correct the next
6254 time we expand this function. */
6256 }
6257 /* Detect modification of read-only values.
6258 (Otherwise done by build_modify_expr.) */
6259 else
6260 {
6266 }
6267 }
6269 /* Those MODIFY_EXPRs could do autoincrements. */
6271 }
6272 \f
6273 /* If RETVAL is the address of, or a reference to, a local variable or
6274 temporary give an appropraite warning. */
6276 static void
6278 tree retval;
6279 {
6284 {
6291 else
6293 }
6300 {
6303 {
6304 /* Get the target. */
6308 }
6312 {
6315 }
6316 }
6323 {
6326 whats_returned);
6327 else
6329 whats_returned);
6331 }
6332 }
6334 /* Check that returning RETVAL from the current function is valid.
6335 Return an expression explicitly showing all conversions required to
6336 change RETVAL into the function return type, and to assign it to
6337 the DECL_RESULT for the function. */
6339 tree
6341 tree retval;
6342 {
6343 tree result;
6344 /* The type actually returned by the function, after any
6345 promotions. */
6346 tree valtype;
6349 /* A `volatile' function is one that isn't supposed to return, ever.
6350 (This is a G++ extension, used to get better code for functions
6351 that call the `volatile' function.) */
6355 /* Check for various simple errors. */
6357 {
6361 }
6363 {
6365 /* If a return statement appears in a handler of the
6366 function-try-block of a constructor, the program is ill-formed. */
6369 /* You can't return a value from a constructor. */
6372 }
6375 {
6378 }
6380 /* When no explicit return-value is given in a function with a named
6381 return value, the named return value is used. */
6389 /* Check for a return statement with no return value in a function
6390 that's supposed to return a value. */
6392 {
6394 /* Clear this, so finish_function won't say that we reach the
6395 end of a non-void function (which we don't, we gave a
6396 return!). */
6398 }
6399 /* Check for a return statement with a value in a function that
6400 isn't supposed to return a value. */
6402 {
6404 /* You can return a `void' value from a function of `void'
6405 type. In that case, we have to evaluate the expression for
6406 its side-effects. */
6408 else
6413 /* There's really no value to return, after all. */
6415 }
6417 /* Remember that this function can sometimes return without a
6418 value. */
6420 else
6421 /* Remember that this function did return a value. */
6424 /* Only operator new(...) throw(), can return NULL [expr.new/13]. */
6428 && ! flag_check_new
6430 warning ("`operator new' must not return NULL unless it is declared `throw()' (or -fcheck-new is in effect)");
6432 /* Effective C++ rule 15. See also start_function. */
6438 /* The fabled Named Return Value optimization, as per [class.copy]/15:
6440 [...] For a function with a class return type, if the expression
6441 in the return statement is the name of a local object, and the cv-
6442 unqualified type of the local object is the same as the function
6443 return type, an implementation is permitted to omit creating the tem-
6444 porary object to hold the function return value [...]
6446 So, if this is a value-returning function that always returns the same
6447 local variable, remember it.
6449 It might be nice to be more flexible, and choose the first suitable
6450 variable even if the function sometimes returns something else, but
6451 then we run the risk of clobbering the variable we chose if the other
6452 returned expression uses the chosen variable somehow. And people expect
6453 this restriction, anyway. (jason 2000-11-19)
6455 See finish_function, genrtl_start_function, and declare_return_variable
6456 for other pieces of this optimization. */
6459 {
6470 (TYPE_MAIN_VARIANT
6473 else
6475 }
6477 /* We don't need to do any conversions when there's nothing being
6478 returned. */
6482 /* Do any required conversions. */
6484 /* No conversions are required. */
6485 ;
6486 else
6487 {
6488 /* The type the function is declared to return. */
6491 /* First convert the value to the function's return type, then
6492 to the type of return value's location to handle the
6493 case that functype is smaller than the valtype. */
6494 retval = convert_for_initialization
6499 /* If the conversion failed, treat this just like `return;'. */
6502 /* We can't initialize a register from a AGGR_INIT_EXPR. */
6508 else
6510 }
6512 /* Actually copy the value returned into the appropriate location. */
6517 }
6519 \f
6520 /* Returns nonzero if the pointer-type FROM can be converted to the
6521 pointer-type TO via a qualification conversion. If CONSTP is -1,
6522 then we return nonzero if the pointers are similar, and the
6523 cv-qualification signature of FROM is a proper subset of that of TO.
6525 If CONSTP is positive, then all outer pointers have been
6526 const-qualified. */
6528 static int
6532 {
6536 {
6545 /* Const and volatile mean something different for function types,
6546 so the usual checks are not appropriate. */
6548 {
6553 {
6556 else
6558 }
6562 }
6565 return
6568 }
6569 }
6571 /* When comparing, say, char ** to char const **, this function takes the
6572 'char *' and 'char const *'. Do not pass non-pointer types to this
6573 function. */
6575 int
6578 {
6580 }
6582 /* Returns 1 if to and from are (possibly multi-level) pointers to the same
6583 type or inheritance-related types, regardless of cv-quals. */
6585 int
6588 {
6590 {
6591 /* Any target type is similar enough to void. */
6613 return comptypes
6616 }
6617 }
6619 /* Like comp_ptr_ttypes, for const_cast. */
6621 static int
6624 {
6626 {
6637 }
6638 }
6640 /* Like comp_ptr_ttypes, for reinterpret_cast. */
6642 static int
6645 {
6649 {
6655 /* Const and volatile mean something different for function types,
6656 so the usual checks are not appropriate. */
6659 {
6667 }
6672 }
6673 }
6675 /* Returns the type qualifiers for this type, including the qualifiers on the
6676 elements for an array type. */
6678 int
6680 tree type;
6681 {
6686 }
6688 /* Returns nonzero if the TYPE contains a mutable member */
6690 int
6692 tree type;
6693 {
6697 }
6699 /* Subroutine of casts_away_constness. Make T1 and T2 point at
6700 exemplar types such that casting T1 to T2 is casting away castness
6701 if and only if there is no implicit conversion from T1 to T2. */
6703 static void
6707 {
6711 /* [expr.const.cast]
6713 For multi-level pointer to members and multi-level mixed pointers
6714 and pointers to members (conv.qual), the "member" aspect of a
6715 pointer to member level is ignored when determining if a const
6716 cv-qualifier has been cast away. */
6722 /* [expr.const.cast]
6724 For two pointer types:
6726 X1 is T1cv1,1 * ... cv1,N * where T1 is not a pointer type
6727 X2 is T2cv2,1 * ... cv2,M * where T2 is not a pointer type
6728 K is min(N,M)
6730 casting from X1 to X2 casts away constness if, for a non-pointer
6731 type T there does not exist an implicit conversion (clause
6732 _conv_) from:
6734 Tcv1,(N-K+1) * cv1,(N-K+2) * ... cv1,N *
6736 to
6738 Tcv2,(M-K+1) * cv2,(M-K+2) * ... cv2,M *. */
6742 {
6748 }
6759 }
6761 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
6762 constness. */
6764 static int
6766 tree t1;
6767 tree t2;
6768 {
6770 {
6771 /* [expr.const.cast]
6773 Casting from an lvalue of type T1 to an lvalue of type T2
6774 using a reference cast casts away constness if a cast from an
6775 rvalue of type "pointer to T1" to the type "pointer to T2"
6776 casts away constness. */
6781 }
6784 /* [expr.const.cast]
6786 Casting from an rvalue of type "pointer to data member of X
6787 of type T1" to the type "pointer to data member of Y of type
6788 T2" casts away constness if a cast from an rvalue of type
6789 "pointer to T1" to the type "pointer to T2" casts away
6790 constness. */
6791 return casts_away_constness
6795 /* Casting away constness is only something that makes sense for
6796 pointer or reference types. */
6801 /* Top-level qualifiers don't matter. */
6809 }
6811 /* Returns TYPE with its cv qualifiers removed
6812 TYPE is T cv* .. *cv where T is not a pointer type,
6813 returns T * .. *. (If T is an array type, then the cv qualifiers
6814 above are those of the array members.) */
6816 static tree
6818 tree type;
6819 {
6825 else
6827 }