| blob | d61e89e6455849a91980fc58886d7674cfbe0d68 |
1 /* Build expressions with type checking for C compiler.
2 Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
23 /* This file is part of the C front end.
24 It contains routines to build C expressions given their operands,
25 including computing the types of the result, C-specific error checks,
26 and some optimization.
28 There are also routines to build RETURN_STMT nodes and CASE_STMT nodes,
29 and to process initializations in declarations (since they work
30 like a strange sort of assignment). */
49 /* Nonzero if we've already printed a "missing braces around initializer"
50 message within this initializer. */
84 \f
85 /* Do `exp = require_complete_type (exp);' to make sure exp
86 does not have an incomplete type. (That includes void types.) */
88 tree
90 {
96 /* First, detect a valid value with a complete type. */
102 }
104 /* Print an error message for invalid use of an incomplete type.
105 VALUE is the expression that was used (or 0 if that isn't known)
106 and TYPE is the type that was invalid. */
108 void
110 {
113 /* Avoid duplicate error message. */
121 else
122 {
123 retry:
124 /* We must print an error message. Be clever about what it says. */
127 {
146 {
148 {
151 }
154 }
160 }
165 else
166 /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL. */
169 }
170 }
172 /* Given a type, apply default promotions wrt unnamed function
173 arguments and return the new type. */
175 tree
177 {
182 {
183 /* Preserve unsignedness if not really getting any wider. */
188 }
191 }
193 /* Return a variant of TYPE which has all the type qualifiers of LIKE
194 as well as those of TYPE. */
196 static tree
198 {
201 }
202 \f
203 /* Return the common type of two types.
204 We assume that comptypes has already been done and returned 1;
205 if that isn't so, this may crash. In particular, we assume that qualifiers
206 match.
208 This is the type for the result of most arithmetic operations
209 if the operands have the given two types. */
211 tree
213 {
216 tree attributes;
218 /* Save time if the two types are the same. */
222 /* If one type is nonsense, use the other. */
228 /* Merge the attributes. */
231 /* Treat an enum type as the unsigned integer type of the same width. */
241 /* If one type is complex, form the common type of the non-complex
242 components, then make that complex. Use T1 or T2 if it is the
243 required type. */
245 {
254 else
256 attributes);
257 }
260 {
263 /* If only one is real, use it as the result. */
271 /* Both real or both integers; use the one with greater precision. */
278 /* Same precision. Prefer longs to ints even when same size. */
283 attributes);
287 {
288 /* But preserve unsignedness from the other type,
289 since long cannot hold all the values of an unsigned int. */
292 else
295 }
297 /* Likewise, prefer long double to double even if same size. */
301 attributes);
303 /* Otherwise prefer the unsigned one. */
307 else
311 /* For two pointers, do this recursively on the target type,
312 and combine the qualifiers of the two types' targets. */
313 /* This code was turned off; I don't know why.
314 But ANSI C specifies doing this with the qualifiers.
315 So I turned it on again. */
316 {
326 }
329 {
331 /* Save space: see if the result is identical to one of the args. */
336 /* Merge the element types, and have a size if either arg has one. */
339 }
342 /* Function types: prefer the one that specified arg types.
343 If both do, merge the arg types. Also merge the return types. */
344 {
352 /* Save space: see if the result is identical to one of the args. */
358 /* Simple way if one arg fails to specify argument types. */
360 {
363 }
365 {
368 }
370 /* If both args specify argument types, we must merge the two
371 lists, argument by argument. */
386 {
387 /* A null type means arg type is not specified.
388 Take whatever the other function type has. */
390 {
393 }
395 {
398 }
400 /* Given wait (union {union wait *u; int *i} *)
401 and wait (union wait *),
402 prefer union wait * as type of parm. */
405 {
406 tree memb;
410 COMPARE_STRICT))
411 {
416 }
417 }
420 {
421 tree memb;
425 COMPARE_STRICT))
426 {
431 }
432 }
434 parm_done: ;
435 }
440 /* ... falls through ... */
441 }
445 }
447 }
448 \f
449 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
450 or various other operations. Return 2 if they are compatible
451 but a warning may be needed if you use them together. */
453 int
455 {
460 /* Suppress errors caused by previously reported errors. */
466 /* If either type is the internal version of sizetype, return the
467 language version. */
476 /* Enumerated types are compatible with integer types, but this is
477 not transitive: two enumerated types in the same translation unit
478 are compatible with each other only if they are the same type. */
488 /* Different classes of types can't be compatible. */
492 /* Qualifiers must match. */
497 /* Allow for two different type nodes which have essentially the same
498 definition. Note that we already checked for equality of the type
499 qualifiers (just above). */
504 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
508 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
512 {
514 /* We must give ObjC the first crack at comparing pointers, since
515 protocol qualifiers may be involved. */
527 {
534 /* Target types must match incl. qualifiers. */
537 flags)))
540 /* Sizes must match unless one is missing or variable. */
547 d1_variable = (! d1_zero
550 d2_variable = (! d2_zero
564 }
567 /* We are dealing with two distinct structs. In assorted Objective-C
568 corner cases, however, these can still be deemed equivalent. */
579 /* The target might allow certain vector types to be compatible. */
586 }
588 }
590 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
591 ignoring their qualifiers. REFLEXIVE is only used by ObjC - set it
592 to 1 or 0 depending if the check of the pointer types is meant to
593 be reflexive or not (typically, assignments are not reflexive,
594 while comparisons are reflexive).
595 */
597 static int
599 {
602 /* Give objc_comptypes a crack at letting these types through. */
612 }
613 \f
614 /* Subroutines of `comptypes'. */
616 /* Determine whether two types derive from the same translation unit.
617 If the CONTEXT chain ends in a null, that type's context is still
618 being parsed, so if two types have context chains ending in null,
619 they're in the same translation unit. */
620 static int
622 {
625 {
630 }
634 {
639 }
642 }
644 /* The C standard says that two structures in different translation
645 units are compatible with each other only if the types of their
646 fields are compatible (among other things). So, consider two copies
647 of this structure: */
651 tree t1;
652 tree t2;
653 };
655 /* Can they be compatible with each other? We choose to break the
656 recursion by allowing those types to be compatible. */
660 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
661 compatible. If the two types are not the same (which has been
662 checked earlier), this can only happen when multiple translation
663 units are being compiled. See C99 6.2.7 paragraph 1 for the exact
664 rules. */
666 static int
668 {
672 /* We have to verify that the tags of the types are the same. This
673 is harder than it looks because this may be a typedef, so we have
674 to go look at the original type. It may even be a typedef of a
675 typedef... */
682 /* C90 didn't have the requirement that the two tags be the same. */
686 /* C90 didn't say what happened if one or both of the types were
687 incomplete; we choose to follow C99 rules here, which is that they
688 are compatible. */
693 {
698 }
701 {
703 {
708 {
713 }
715 }
718 {
723 {
735 {
750 }
754 }
756 }
759 {
770 {
785 }
790 }
794 }
795 }
797 /* Return 1 if two function types F1 and F2 are compatible.
798 If either type specifies no argument types,
799 the other must specify a fixed number of self-promoting arg types.
800 Otherwise, if one type specifies only the number of arguments,
801 the other must specify that number of self-promoting arg types.
802 Otherwise, the argument types must match. */
804 static int
806 {
808 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
816 /* 'volatile' qualifiers on a function's return type mean the function
817 is noreturn. */
833 /* An unspecified parmlist matches any specified parmlist
834 whose argument types don't need default promotions. */
837 {
840 /* If one of these types comes from a non-prototype fn definition,
841 compare that with the other type's arglist.
842 If they don't match, ask for a warning (but no error). */
845 flags))
848 }
850 {
855 flags))
858 }
860 /* Both types have argument lists: compare them and propagate results. */
863 }
865 /* Check two lists of types for compatibility,
866 returning 0 for incompatible, 1 for compatible,
867 or 2 for compatible with warning. */
869 static int
871 {
872 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
877 {
880 /* If one list is shorter than the other,
881 they fail to match. */
884 /* A null pointer instead of a type
885 means there is supposed to be an argument
886 but nothing is specified about what type it has.
887 So match anything that self-promotes. */
889 {
892 }
894 {
897 }
898 /* If one of the lists has an error marker, ignore this arg. */
901 ;
904 flags)))
905 {
906 /* Allow wait (union {union wait *u; int *i} *)
907 and wait (union wait *) to be compatible. */
914 {
915 tree memb;
919 flags))
923 }
930 {
931 tree memb;
935 flags))
939 }
940 else
942 }
944 /* comptypes said ok, but record if it said to warn. */
950 }
951 }
952 \f
953 /* Compute the size to increment a pointer by. */
955 tree
957 {
964 {
967 }
969 /* Convert in case a char is more than one unit. */
973 }
974 \f
975 /* Return either DECL or its known constant value (if it has one). */
977 tree
979 {
981 in a place where a variable is invalid. */
987 /* This is invalid if initial value is not constant.
988 If it has either a function call, a memory reference,
989 or a variable, then re-evaluating it could give different results. */
991 /* Check for cases where this is sub-optimal, even though valid. */
995 }
997 /* Return either DECL or its known constant value (if it has one), but
998 return DECL if pedantic or DECL has mode BLKmode. This is for
999 bug-compatibility with the old behavior of decl_constant_value
1000 (before GCC 3.0); every use of this function is a bug and it should
1001 be removed before GCC 3.1. It is not appropriate to use pedantic
1002 in a way that affects optimization, and BLKmode is probably not the
1003 right test for avoiding misoptimizations either. */
1005 static tree
1007 {
1010 else
1012 }
1015 /* Perform the default conversion of arrays and functions to pointers.
1016 Return the result of converting EXP. For any other expression, just
1017 return EXP. */
1019 static tree
1021 {
1022 tree orig_exp;
1027 /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1028 an lvalue.
1030 Do not use STRIP_NOPS here! It will remove conversions from pointer
1031 to integer and cause infinite recursion. */
1036 {
1040 }
1042 /* Preserve the original expression code. */
1047 {
1049 }
1051 {
1052 tree adr;
1054 tree ptrtype;
1060 {
1063 }
1066 restype
1077 {
1081 }
1085 {
1086 /* Before C99, non-lvalue arrays do not decay to pointers.
1087 Normally, using such an array would be invalid; but it can
1088 be used correctly inside sizeof or as a statement expression.
1089 Thus, do not give an error here; an error will result later. */
1091 }
1096 {
1097 /* ??? This is not really quite correct
1098 in that the type of the operand of ADDR_EXPR
1099 is not the target type of the type of the ADDR_EXPR itself.
1100 Question is, can this lossage be avoided? */
1107 }
1108 /* This way is better for a COMPONENT_REF since it can
1109 simplify the offset for a component. */
1112 }
1114 }
1116 /* Perform default promotions for C data used in expressions.
1117 Arrays and functions are converted to pointers;
1118 enumeral types or short or char, to int.
1119 In addition, manifest constants symbols are replaced by their values. */
1121 tree
1123 {
1124 tree orig_exp;
1131 /* Constants can be used directly unless they're not loadable. */
1135 /* Replace a nonvolatile const static variable with its value unless
1136 it is an array, in which case we must be sure that taking the
1137 address of the array produces consistent results. */
1139 {
1142 }
1144 /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
1145 an lvalue.
1147 Do not use STRIP_NOPS here! It will remove conversions from pointer
1148 to integer and cause infinite recursion. */
1155 /* Preserve the original expression code. */
1159 /* Normally convert enums to int,
1160 but convert wide enums to something wider. */
1162 {
1170 }
1174 /* If it's thinner than an int, promote it like a
1175 c_promoting_integer_type_p, otherwise leave it alone. */
1181 {
1182 /* Preserve unsignedness if not really getting any wider. */
1188 }
1191 {
1194 }
1196 }
1197 \f
1198 /* Look up COMPONENT in a structure or union DECL.
1200 If the component name is not found, returns NULL_TREE. Otherwise,
1201 the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1202 stepping down the chain to the component, which is in the last
1203 TREE_VALUE of the list. Normally the list is of length one, but if
1204 the component is embedded within (nested) anonymous structures or
1205 unions, the list steps down the chain to the component. */
1207 static tree
1209 {
1211 tree field;
1213 /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1214 to the field elements. Use a binary search on this array to quickly
1215 find the element. Otherwise, do a linear search. TYPE_LANG_SPECIFIC
1216 will always be set for structures which have many elements. */
1219 {
1227 {
1232 {
1233 /* Step through all anon unions in linear fashion. */
1235 {
1239 {
1244 }
1245 }
1247 /* Entire record is only anon unions. */
1251 /* Restart the binary search, with new lower bound. */
1253 }
1259 else
1261 }
1267 }
1268 else
1269 {
1271 {
1275 {
1280 }
1284 }
1288 }
1291 }
1293 /* Make an expression to refer to the COMPONENT field of
1294 structure or union value DATUM. COMPONENT is an IDENTIFIER_NODE. */
1296 tree
1298 {
1302 tree ref;
1304 /* If DATUM is a COMPOUND_EXPR, move our reference inside it.
1305 Ensure that the arguments are not lvalues; otherwise,
1306 if the component is an array, it would wrongly decay to a pointer in
1307 C89 mode.
1308 We cannot do this with a COND_EXPR, because in a conditional expression
1309 the default promotions are applied to both sides, and this would yield
1310 the wrong type of the result; for example, if the components have
1311 type "char". */
1313 {
1315 {
1319 }
1322 }
1324 /* See if there is a field or component with name COMPONENT. */
1327 {
1329 {
1332 }
1337 {
1342 }
1344 /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1345 This might be better solved in future the way the C++ front
1346 end does it - by giving the anonymous entities each a
1347 separate name and type, and then have build_component_ref
1348 recursively call itself. We can't do that here. */
1349 do
1350 {
1368 }
1372 }
1378 }
1379 \f
1380 /* Given an expression PTR for a pointer, return an expression
1381 for the value pointed to.
1382 ERRORSTRING is the name of the operator to appear in error messages. */
1384 tree
1386 {
1391 {
1396 else
1397 {
1402 {
1405 }
1409 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1410 so that we get the proper error message if the result is used
1411 to assign to. Also, &* is supposed to be a no-op.
1412 And ANSI C seems to specify that the type of the result
1413 should be the const type. */
1414 /* A de-reference of a pointer to const is not a const. It is valid
1415 to change it via some other pointer. */
1421 }
1422 }
1426 }
1428 /* This handles expressions of the form "a[i]", which denotes
1429 an array reference.
1431 This is logically equivalent in C to *(a+i), but we may do it differently.
1432 If A is a variable or a member, we generate a primitive ARRAY_REF.
1433 This avoids forcing the array out of registers, and can work on
1434 arrays that are not lvalues (for example, members of structures returned
1435 by functions). */
1437 tree
1439 {
1441 {
1444 }
1452 {
1455 /* Subscripting with type char is likely to lose
1456 on a machine where chars are signed.
1457 So warn on any machine, but optionally.
1458 Don't warn for unsigned char since that type is safe.
1459 Don't warn for signed char because anyone who uses that
1460 must have done so deliberately. */
1465 /* Apply default promotions *after* noticing character types. */
1468 /* Require integer *after* promotion, for sake of enums. */
1470 {
1473 }
1475 /* An array that is indexed by a non-constant
1476 cannot be stored in a register; we must be able to do
1477 address arithmetic on its address.
1478 Likewise an array of elements of variable size. */
1482 {
1485 }
1486 /* An array that is indexed by a constant value which is not within
1487 the array bounds cannot be stored in a register either; because we
1488 would get a crash in store_bit_field/extract_bit_field when trying
1489 to access a non-existent part of the register. */
1493 {
1496 }
1499 {
1507 }
1511 /* Array ref is const/volatile if the array elements are
1512 or if the array is. */
1521 /* This was added by rms on 16 Nov 91.
1522 It fixes vol struct foo *a; a->elts[1]
1523 in an inline function.
1524 Hope it doesn't break something else. */
1527 }
1529 {
1533 /* Do the same warning check as above, but only on the part that's
1534 syntactically the index and only if it is also semantically
1535 the index. */
1541 /* Put the integer in IND to simplify error checking. */
1543 {
1547 }
1554 {
1557 }
1559 {
1562 }
1566 }
1567 }
1568 \f
1569 /* Build an external reference to identifier ID. FUN indicates
1570 whether this will be used for a function call. */
1571 tree
1573 {
1574 tree ref;
1579 {
1580 /* Properly declared variable or function reference. */
1584 {
1588 }
1589 else
1591 }
1595 /* Implicit function declaration. */
1598 /* Don't complain about something that's already been
1599 complained about. */
1601 else
1602 {
1605 }
1618 {
1621 }
1627 {
1632 }
1635 }
1637 /* Build a function call to function FUNCTION with parameters PARAMS.
1638 PARAMS is a list--a chain of TREE_LIST nodes--in which the
1639 TREE_VALUE of each node is a parameter-expression.
1640 FUNCTION's data type may be a function type or a pointer-to-function. */
1642 tree
1644 {
1646 tree coerced_params;
1648 tree tem;
1650 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
1653 /* Convert anything with function type to a pointer-to-function. */
1655 {
1658 /* Differs from default_conversion by not setting TREE_ADDRESSABLE
1659 (because calling an inline function does not mean the function
1660 needs to be separately compiled). */
1666 }
1667 else
1677 {
1680 }
1685 /* fntype now gets the type of function pointed to. */
1688 /* Check that the function is called through a compatible prototype.
1689 If it is not, replace the call by a trap, wrapped up in a compound
1690 expression if necessary. This has the nice side-effect to prevent
1691 the tree-inliner from generating invalid assignment trees which may
1692 blow up in the RTL expander later.
1694 ??? This doesn't work for Objective-C because objc_comptypes
1695 refuses to compare function prototypes, yet the compiler appears
1696 to build calls that are flagged as invalid by C's comptypes. */
1702 {
1705 NULL_TREE);
1707 /* This situation leads to run-time undefined behavior. We can't,
1708 therefore, simply error unless we can prove that all possible
1709 executions of the program must execute the code. */
1714 else
1715 {
1716 tree rhs;
1721 NULL_TREE));
1722 else
1726 }
1727 }
1729 /* Convert the parameters to the types declared in the
1730 function prototype, or apply default promotions. */
1732 coerced_params
1735 /* Check that the arguments to the function are valid. */
1739 /* Recognize certain built-in functions so we can make tree-codes
1740 other than CALL_EXPR. We do this when it enables fold-const.c
1741 to do something useful. */
1746 {
1751 }
1761 }
1762 \f
1763 /* Convert the argument expressions in the list VALUES
1764 to the types in the list TYPELIST. The result is a list of converted
1765 argument expressions.
1767 If TYPELIST is exhausted, or when an element has NULL as its type,
1768 perform the default conversions.
1770 PARMLIST is the chain of parm decls for the function being called.
1771 It may be 0, if that info is not available.
1772 It is used only for generating error messages.
1774 NAME is an IDENTIFIER_NODE or 0. It is used only for error messages.
1776 This is also where warnings about wrong number of args are generated.
1778 Both VALUES and the returned value are chains of TREE_LIST nodes
1779 with the elements of the list in the TREE_VALUE slots of those nodes. */
1781 static tree
1783 {
1788 /* Scan the given expressions and types, producing individual
1789 converted arguments and pushing them on RESULT in reverse order. */
1792 valtail;
1794 {
1799 {
1803 else
1806 }
1808 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
1809 /* Do not use STRIP_NOPS here! We do not want an enumerator with value 0
1810 to convert automatically to a pointer. */
1819 {
1820 /* Formal parm type is specified by a function prototype. */
1821 tree parmval;
1824 {
1827 }
1828 else
1829 {
1830 /* Optionally warn about conversions that
1831 differ from the default conversions. */
1833 {
1838 warn_for_assignment ("%s as integer rather than floating due to prototype", (char *) 0, name, parmnum + 1);
1841 warn_for_assignment ("%s as integer rather than complex due to prototype", (char *) 0, name, parmnum + 1);
1844 warn_for_assignment ("%s as complex rather than floating due to prototype", (char *) 0, name, parmnum + 1);
1847 warn_for_assignment ("%s as floating rather than integer due to prototype", (char *) 0, name, parmnum + 1);
1850 warn_for_assignment ("%s as complex rather than integer due to prototype", (char *) 0, name, parmnum + 1);
1853 warn_for_assignment ("%s as floating rather than complex due to prototype", (char *) 0, name, parmnum + 1);
1854 /* ??? At some point, messages should be written about
1855 conversions between complex types, but that's too messy
1856 to do now. */
1859 {
1860 /* Warn if any argument is passed as `float',
1861 since without a prototype it would be `double'. */
1863 warn_for_assignment ("%s as `float' rather than `double' due to prototype", (char *) 0, name, parmnum + 1);
1864 }
1865 /* Detect integer changing in width or signedness.
1866 These warnings are only activated with
1867 -Wconversion, not with -Wtraditional. */
1870 {
1877 /* No warning if function asks for enum
1878 and the actual arg is that enum type. */
1879 ;
1881 warn_for_assignment ("%s with different width due to prototype", (char *) 0, name, parmnum + 1);
1883 ;
1884 /* Don't complain if the formal parameter type
1885 is an enum, because we can't tell now whether
1886 the value was an enum--even the same enum. */
1888 ;
1891 /* Change in signedness doesn't matter
1892 if a constant value is unaffected. */
1893 ;
1894 /* Likewise for a constant in a NOP_EXPR. */
1898 ;
1899 /* If the value is extended from a narrower
1900 unsigned type, it doesn't matter whether we
1901 pass it as signed or unsigned; the value
1902 certainly is the same either way. */
1905 ;
1908 else
1910 }
1911 }
1921 }
1923 }
1927 /* Convert `float' to `double'. */
1929 else
1930 /* Convert `short' and `char' to full-size `int'. */
1935 }
1938 {
1942 else
1944 }
1947 }
1948 \f
1949 /* This is the entry point used by the parser
1950 for binary operators in the input.
1951 In addition to constructing the expression,
1952 we check for operands that were written with other binary operators
1953 in a way that is likely to confuse the user. */
1955 tree
1957 {
1974 /* Check for cases such as x+y<<z which users are likely
1975 to misinterpret. If parens are used, C_EXP_ORIGINAL_CODE
1976 is cleared to prevent these warnings. */
1978 {
1980 {
1984 }
1987 {
1991 }
1994 {
2000 /* Check cases like x|y==z */
2003 }
2006 {
2012 /* Check cases like x^y==z */
2015 }
2018 {
2022 /* Check cases like x&y==z */
2025 }
2026 }
2028 /* Similarly, check for cases like 1<=i<=10 that are probably errors. */
2039 /* Record the code that was specified in the source,
2040 for the sake of warnings about confusing nesting. */
2043 else
2044 {
2046 /* We used to use NOP_EXPR rather than NON_LVALUE_EXPR
2047 so that convert_for_assignment wouldn't strip it.
2048 That way, we got warnings for things like p = (1 - 1).
2049 But it turns out we should not get those warnings. */
2053 }
2056 }
2057 \f
2059 /* Return true if `t' is known to be non-negative. */
2061 int
2063 {
2065 {
2068 /* Find the last statement in the chain, ignoring the final
2069 * scope statement */
2074 }
2076 }
2078 /* Return a tree for the difference of pointers OP0 and OP1.
2079 The resulting tree has type int. */
2081 static tree
2083 {
2092 {
2097 }
2099 /* If the conversion to ptrdiff_type does anything like widening or
2100 converting a partial to an integral mode, we get a convert_expression
2101 that is in the way to do any simplifications.
2102 (fold-const.c doesn't know that the extra bits won't be needed.
2103 split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2104 different mode in place.)
2105 So first try to find a common term here 'by hand'; we want to cover
2106 at least the cases that occur in legal static initializers. */
2111 {
2114 }
2115 else
2119 {
2122 }
2123 else
2127 {
2130 }
2133 /* First do the subtraction as integers;
2134 then drop through to build the divide operator.
2135 Do not do default conversions on the minus operator
2136 in case restype is a short type. */
2140 /* This generates an error if op1 is pointer to incomplete type. */
2144 /* This generates an error if op0 is pointer to incomplete type. */
2147 /* Divide by the size, in easiest possible way. */
2155 }
2156 \f
2157 /* Construct and perhaps optimize a tree representation
2158 for a unary operation. CODE, a tree_code, specifies the operation
2159 and XARG is the operand.
2160 For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2161 the default promotions (such as from short to int).
2162 For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2163 allows non-lvalues; this is only used to handle conversion of non-lvalue
2164 arrays to pointers in C99. */
2166 tree
2168 {
2169 /* No default_conversion here. It causes trouble for ADDR_EXPR. */
2173 tree val;
2182 {
2184 /* This is used for unary plus, because a CONVERT_EXPR
2185 is enough to prevent anybody from looking inside for
2186 associativity, but won't generate any code. */
2189 {
2192 }
2202 {
2205 }
2212 {
2215 }
2217 {
2223 }
2224 else
2225 {
2228 }
2233 {
2236 }
2242 /* Conjugating a real value is a no-op, but allow it anyway. */
2245 {
2248 }
2257 /* These will convert to a pointer. */
2259 {
2262 }
2274 else
2282 else
2290 /* Increment or decrement the real part of the value,
2291 and don't change the imaginary part. */
2293 {
2304 }
2306 /* Report invalid types. */
2310 {
2313 else
2317 }
2319 {
2320 tree inc;
2326 /* Compute the increment. */
2329 {
2330 /* If pointer target is an undefined struct,
2331 we just cannot know how to do the arithmetic. */
2333 {
2336 else
2338 }
2342 {
2345 else
2347 }
2350 }
2351 else
2356 /* Complain about anything else that is not a true lvalue. */
2363 /* Report a read-only lvalue. */
2372 else
2379 }
2382 /* Note that this operation never does default_conversion. */
2384 /* Let &* cancel out to simplify resulting code. */
2386 {
2387 /* Don't let this be an lvalue. */
2391 }
2393 /* For &x[y], return x+y */
2395 {
2400 }
2402 /* Anything not already handled and not a true memory reference
2403 or a non-lvalue array is an error. */
2408 /* Ordinary case; arg is a COMPONENT_REF or a decl. */
2411 /* If the lvalue is const or volatile, merge that into the type
2412 to which the address will point. Note that you can't get a
2413 restricted pointer by taking the address of something, so we
2414 only have to deal with `const' and `volatile' here. */
2426 {
2427 tree addr;
2430 {
2436 {
2440 }
2445 }
2446 else
2449 /* Address of a static or external variable or
2450 file-scope function counts as a constant. */
2456 }
2460 }
2465 }
2467 /* Return nonzero if REF is an lvalue valid for this language.
2468 Lvalues can be assigned, unless their type has TYPE_READONLY.
2469 Lvalues can have their address taken, unless they have DECL_REGISTER. */
2471 int
2473 {
2477 {
2502 }
2503 }
2505 /* Return nonzero if REF is an lvalue valid for this language;
2506 otherwise, print an error message and return zero. */
2508 int
2510 {
2517 }
2519 \f
2520 /* Warn about storing in something that is `const'. */
2522 void
2524 {
2526 {
2529 else
2532 }
2536 else
2538 }
2539 \f
2540 /* Mark EXP saying that we need to be able to take the
2541 address of it; it should not be allocated in a register.
2542 Returns true if successful. */
2544 bool
2546 {
2551 {
2554 {
2558 }
2560 /* ... fall through ... */
2580 {
2582 {
2586 }
2589 }
2591 {
2593 {
2597 }
2599 /* If we are making this addressable due to its having
2600 volatile components, give a different error message. Also
2601 handle the case of an unnamed parameter by not trying
2602 to give the name. */
2605 {
2608 }
2612 }
2615 /* drops in */
2618 /* drops out */
2621 }
2622 }
2623 \f
2624 /* Build and return a conditional expression IFEXP ? OP1 : OP2. */
2626 tree
2628 {
2629 tree type1;
2630 tree type2;
2638 /* Promote both alternatives. */
2655 /* C90 does not permit non-lvalue arrays in conditional expressions.
2656 In C99 they will be pointers by now. */
2658 {
2661 }
2663 /* Quickly detect the usual case where op1 and op2 have the same type
2664 after promotion. */
2666 {
2669 else
2671 }
2676 {
2679 /* If -Wsign-compare, warn here if type1 and type2 have
2680 different signedness. We'll promote the signed to unsigned
2681 and later code won't know it used to be different.
2682 Do this check on the original types, so that explicit casts
2683 will be considered, but default promotions won't. */
2685 {
2690 {
2691 /* Do not warn if the result type is signed, since the
2692 signed type will only be chosen if it can represent
2693 all the values of the unsigned type. */
2696 /* Do not warn if the signed quantity is an unsuffixed
2697 integer literal (or some static constant expression
2698 involving such literals) and it is non-negative. */
2702 else
2704 }
2705 }
2706 }
2708 {
2712 }
2714 {
2724 {
2729 }
2731 {
2736 }
2737 else
2738 {
2741 }
2742 }
2744 {
2747 else
2748 {
2750 }
2752 }
2754 {
2757 else
2758 {
2760 }
2762 }
2765 {
2768 else
2769 {
2772 }
2773 }
2775 /* Merge const and volatile flags of the incoming types. */
2776 result_type
2790 }
2791 \f
2792 /* Given a list of expressions, return a compound expression
2793 that performs them all and returns the value of the last of them. */
2795 tree
2797 {
2799 }
2801 static tree
2803 {
2804 tree rest;
2807 {
2808 /* Convert arrays and functions to pointers when there
2809 really is a comma operator. */
2814 /* Don't let (0, 0) be null pointer constant. */
2818 }
2823 {
2824 /* The left-hand operand of a comma expression is like an expression
2825 statement: with -Wextra or -Wunused, we should warn if it doesn't have
2826 any side-effects, unless it was explicitly cast to (void). */
2831 }
2833 /* With -Wunused, we should also warn if the left-hand operand does have
2834 side-effects, but computes a value which is not used. For example, in
2835 `foo() + bar(), baz()' the result of the `+' operator is not used,
2836 so we should issue a warning. */
2841 }
2843 /* Build an expression representing a cast to type TYPE of expression EXPR. */
2845 tree
2847 {
2853 /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
2854 only in <protocol> qualifications. But when constructing cast expressions,
2855 the protocols do matter and must be kept around. */
2860 {
2863 }
2866 {
2869 }
2872 {
2874 {
2878 }
2879 }
2881 {
2882 tree field;
2891 {
2892 tree t;
2902 }
2905 }
2906 else
2907 {
2910 /* If casting to void, avoid the error that would come
2911 from default_conversion in the case of a non-lvalue array. */
2915 /* Convert functions and arrays to pointers,
2916 but don't convert any other types. */
2920 /* Optionally warn about potentially worrisome casts. */
2925 {
2931 /* Check that the qualifiers on IN_TYPE are a superset of
2932 the qualifiers of IN_OTYPE. The outermost level of
2933 POINTER_TYPE nodes is uninteresting and we stop as soon
2934 as we hit a non-POINTER_TYPE node on either type. */
2935 do
2936 {
2940 /* GNU C allows cv-qualified function types. 'const'
2941 means the function is very pure, 'volatile' means it
2942 can't return. We need to warn when such qualifiers
2943 are added, not when they're taken away. */
2947 else
2949 }
2957 /* There are qualifiers present in IN_OTYPE that are not
2958 present in IN_TYPE. */
2960 }
2962 /* Warn about possible alignment problems. */
2968 /* Don't warn about opaque types, where the actual alignment
2969 restriction is unknown. */
2990 /* Don't warn about converting any constant. */
3000 {
3001 /* Casting the address of a decl to non void pointer. Warn
3002 if the cast breaks type based aliasing. */
3009 }
3011 /* If pedantic, warn for conversions between function and object
3012 pointer types, except for converting a null pointer constant
3013 to function pointer type. */
3031 /* Replace a nonvolatile const static variable with its value. */
3036 /* Ignore any integer overflow caused by the cast. */
3038 {
3041 }
3042 }
3044 /* Don't let (void *) (FOO *) 0 be a null pointer constant. */
3050 /* Don't let a cast be an lvalue. */
3055 }
3057 /* Interpret a cast of expression EXPR to type TYPE. */
3058 tree
3060 {
3063 /* This avoids warnings about unprototyped casts on
3064 integers. E.g. "#define SIG_DFL (void(*)())0". */
3071 }
3073 \f
3074 /* Build an assignment expression of lvalue LHS from value RHS.
3075 MODIFYCODE is the code for a binary operator that we use
3076 to combine the old value of LHS with RHS to get the new value.
3077 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment. */
3079 tree
3081 {
3082 tree result;
3083 tree newrhs;
3087 /* Types that aren't fully specified cannot be used in assignments. */
3090 /* Avoid duplicate error messages from operands that had errors. */
3094 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
3095 /* Do not use STRIP_NOPS here. We do not want an enumerator
3096 whose value is 0 to count as a null pointer constant. */
3102 /* If a binary op has been requested, combine the old LHS value with the RHS
3103 producing the value we should actually store into the LHS. */
3106 {
3109 }
3114 /* Warn about storing in something that is `const'. */
3122 /* If storing into a structure or union member,
3123 it has probably been given type `int'.
3124 Compute the type that would go with
3125 the actual amount of storage the member occupies. */
3134 /* If storing in a field that is in actuality a short or narrower than one,
3135 we must store in the field in its actual type. */
3138 {
3141 }
3143 /* Convert new value to destination type. */
3150 /* Scan operands */
3155 /* If we got the LHS in a different type for storing in,
3156 convert the result back to the nominal type of LHS
3157 so that the value we return always has the same type
3158 as the LHS argument. */
3164 }
3165 \f
3166 /* Convert value RHS to type TYPE as preparation for an assignment
3167 to an lvalue of type TYPE.
3168 The real work of conversion is done by `convert'.
3169 The purpose of this function is to generate error messages
3170 for assignments that are not allowed in C.
3171 ERRTYPE is a string to use in error messages:
3172 "assignment", "return", etc. If it is null, this is parameter passing
3173 for a function call (and different error messages are output).
3175 FUNNAME is the name of the function being called,
3176 as an IDENTIFIER_NODE, or null.
3177 PARMNUM is the number of the argument, for printing in error messages. */
3179 static tree
3182 {
3184 tree rhstype;
3187 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
3188 /* Do not use STRIP_NOPS here. We do not want an enumerator
3189 whose value is 0 to count as a null pointer constant. */
3206 {
3208 /* Check for Objective-C protocols. This will automatically
3209 issue a warning if there are protocol violations. No need to
3210 use the return value. */
3214 }
3217 {
3220 }
3221 /* A type converts to a reference to it.
3222 This code doesn't fully support references, it's just for the
3223 special case of va_start and va_copy. */
3226 {
3228 {
3231 }
3236 /* We already know that these two types are compatible, but they
3237 may not be exactly identical. In fact, `TREE_TYPE (type)' is
3238 likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3239 likely to be va_list, a typedef to __builtin_va_list, which
3240 is different enough that it will cause problems later. */
3246 }
3247 /* Some types can interconvert without explicit casts. */
3252 /* Arithmetic types all interconvert, and enum is treated like int. */
3261 /* Conversion to a transparent union from its member types.
3262 This applies only to function arguments. */
3264 {
3265 tree memb_types;
3270 {
3281 {
3285 /* Any non-function converts to a [const][volatile] void *
3286 and vice versa; otherwise, targets must be the same.
3287 Meanwhile, the lhs target must have all the qualifiers of
3288 the rhs. */
3291 {
3292 /* If this type won't generate any warnings, use it. */
3302 /* Keep looking for a better type, but remember this one. */
3305 }
3306 }
3308 /* Can convert integer zero to any pointer type. */
3312 {
3315 }
3316 }
3319 {
3321 {
3322 /* We have only a marginally acceptable member type;
3323 it needs a warning. */
3327 /* Const and volatile mean something different for function
3328 types, so the usual warnings are not appropriate. */
3331 {
3332 /* Because const and volatile on functions are
3333 restrictions that say the function will not do
3334 certain things, it is okay to use a const or volatile
3335 function where an ordinary one is wanted, but not
3336 vice-versa. */
3340 }
3344 parmnum);
3345 }
3351 }
3352 }
3354 /* Conversions among pointers */
3357 {
3363 /* Opaque pointers are treated like void pointers. */
3369 /* Any non-function converts to a [const][volatile] void *
3370 and vice versa; otherwise, targets must be the same.
3371 Meanwhile, the lhs target must have all the qualifiers of the rhs. */
3374 || is_opaque_pointer
3377 {
3380 ||
3382 /* Check TREE_CODE to catch cases like (void *) (char *) 0
3383 which are not ANSI null ptr constants. */
3388 /* Const and volatile mean something different for function types,
3389 so the usual warnings are not appropriate. */
3392 {
3396 /* If this is not a case of ignoring a mismatch in signedness,
3397 no warning. */
3400 ;
3401 /* If there is a mismatch, do warn. */
3405 }
3408 {
3409 /* Because const and volatile on functions are restrictions
3410 that say the function will not do certain things,
3411 it is okay to use a const or volatile function
3412 where an ordinary one is wanted, but not vice-versa. */
3416 }
3417 }
3418 else
3422 }
3424 {
3427 }
3429 {
3430 /* An explicit constant 0 can convert to a pointer,
3431 or one that results from arithmetic, even including
3432 a cast to integer type. */
3434 &&
3443 }
3445 {
3449 }
3454 {
3456 {
3462 else
3465 }
3466 else
3468 parmnum);
3469 }
3470 else
3474 }
3476 /* Convert VALUE for assignment into inlined parameter PARM. ARGNUM
3477 is used for error and waring reporting and indicates which argument
3478 is being processed. */
3480 tree
3482 {
3485 /* If FN was prototyped, the value has been converted already
3486 in convert_arguments. */
3499 }
3501 /* Print a warning using MSGID.
3502 It gets OPNAME as its one parameter.
3503 if OPNAME is null and ARGNUM is 0, it is replaced by "passing arg of `FUNCTION'".
3504 Otherwise if OPNAME is null, it is replaced by "passing arg ARGNUM of `FUNCTION'".
3505 FUNCTION and ARGNUM are handled specially if we are building an
3506 Objective-C selector. */
3508 static void
3511 {
3513 {
3518 {
3521 }
3523 {
3525 {
3526 /* Function name is known; supply it. */
3532 }
3533 else
3534 {
3535 /* Function name unknown (call through ptr). */
3539 }
3540 }
3542 {
3543 /* Function name is known; supply it. */
3549 }
3550 else
3551 {
3552 /* Function name unknown (call through ptr); just give arg number. */
3556 }
3558 }
3560 }
3561 \f
3562 /* If VALUE is a compound expr all of whose expressions are constant, then
3563 return its value. Otherwise, return error_mark_node.
3565 This is for handling COMPOUND_EXPRs as initializer elements
3566 which is allowed with a warning when -pedantic is specified. */
3568 static tree
3570 {
3572 {
3577 endtype);
3578 }
3582 else
3584 }
3585 \f
3586 /* Perform appropriate conversions on the initial value of a variable,
3587 store it in the declaration DECL,
3588 and print any error messages that are appropriate.
3589 If the init is invalid, store an ERROR_MARK. */
3591 void
3593 {
3596 /* If variable's type was invalidly declared, just ignore it. */
3602 /* Digest the specified initializer into an expression. */
3606 /* Store the expression if valid; else report error. */
3614 /* ANSI wants warnings about out-of-range constant initializers. */
3618 /* Check if we need to set array size from compound literal size. */
3622 {
3630 {
3634 {
3635 /* For int foo[] = (int [3]){1}; we need to set array size
3636 now since later on array initializer will be just the
3637 brace enclosed list of the compound literal. */
3641 }
3642 }
3643 }
3644 }
3645 \f
3646 /* Methods for storing and printing names for error messages. */
3648 /* Implement a spelling stack that allows components of a name to be pushed
3649 and popped. Each element on the stack is this structure. */
3651 struct spelling
3652 {
3654 union
3655 {
3659 };
3661 #define SPELLING_STRING 1
3662 #define SPELLING_MEMBER 2
3663 #define SPELLING_BOUNDS 3
3669 /* Macros to save and restore the spelling stack around push_... functions.
3670 Alternative to SAVE_SPELLING_STACK. */
3672 #define SPELLING_DEPTH() (spelling - spelling_base)
3673 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
3675 /* Push an element on the spelling stack with type KIND and assign VALUE
3676 to MEMBER. */
3678 #define PUSH_SPELLING(KIND, VALUE, MEMBER) \
3679 { \
3680 int depth = SPELLING_DEPTH (); \
3681 \
3682 if (depth >= spelling_size) \
3683 { \
3684 spelling_size += 10; \
3685 if (spelling_base == 0) \
3686 spelling_base = xmalloc (spelling_size * sizeof (struct spelling)); \
3687 else \
3688 spelling_base = xrealloc (spelling_base, \
3689 spelling_size * sizeof (struct spelling)); \
3690 RESTORE_SPELLING_DEPTH (depth); \
3691 } \
3692 \
3693 spelling->kind = (KIND); \
3694 spelling->MEMBER = (VALUE); \
3695 spelling++; \
3696 }
3698 /* Push STRING on the stack. Printed literally. */
3700 static void
3702 {
3704 }
3706 /* Push a member name on the stack. Printed as '.' STRING. */
3708 static void
3710 {
3714 }
3716 /* Push an array bounds on the stack. Printed as [BOUNDS]. */
3718 static void
3720 {
3722 }
3724 /* Compute the maximum size in bytes of the printed spelling. */
3726 static int
3728 {
3733 {
3736 else
3738 }
3741 }
3743 /* Print the spelling to BUFFER and return it. */
3747 {
3753 {
3756 }
3757 else
3758 {
3763 ;
3764 }
3767 }
3769 /* Issue an error message for a bad initializer component.
3770 MSGID identifies the message.
3771 The component name is taken from the spelling stack. */
3773 void
3775 {
3782 }
3784 /* Issue a pedantic warning for a bad initializer component.
3785 MSGID identifies the message.
3786 The component name is taken from the spelling stack. */
3788 void
3790 {
3797 }
3799 /* Issue a warning for a bad initializer component.
3800 MSGID identifies the message.
3801 The component name is taken from the spelling stack. */
3803 static void
3805 {
3812 }
3813 \f
3814 /* Digest the parser output INIT as an initializer for type TYPE.
3815 Return a C expression of type TYPE to represent the initial value.
3817 REQUIRE_CONSTANT requests an error if non-constant initializers or
3818 elements are seen. */
3820 static tree
3822 {
3831 /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue. */
3832 /* Do not use STRIP_NOPS here. We do not want an enumerator
3833 whose value is 0 to count as a null pointer constant. */
3839 /* Initialization of an array of chars from a string constant
3840 optionally enclosed in braces. */
3843 {
3851 {
3859 {
3862 }
3866 {
3869 }
3875 /* Subtract 1 (or sizeof (wchar_t))
3876 because it's ok to ignore the terminating null char
3877 that is counted in the length of the constant. */
3888 }
3889 }
3891 /* Build a VECTOR_CST from a *constant* vector constructor. If the
3892 vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
3893 below and handle as a constructor. */
3897 {
3901 COMPARE_STRICT))
3903 else
3905 }
3907 /* Any type can be initialized
3908 from an expression of the same type, optionally with braces. */
3925 {
3927 {
3931 {
3934 }
3935 }
3938 /* Although the types are compatible, we may require a
3939 conversion. */
3944 {
3945 /* As an extension, allow initializing objects with static storage
3946 duration with compound literals (which are then treated just as
3947 the brace enclosed list they contain). */
3950 }
3954 {
3957 }
3962 /* Compound expressions can only occur here if -pedantic or
3963 -pedantic-errors is specified. In the later case, we always want
3964 an error. In the former case, we simply want a warning. */
3967 {
3968 inside_init
3973 else
3977 }
3980 /* This test catches things like `7 / 0' which
3981 result in an expression for which TREE_CONSTANT
3982 is true, but which is not actually something
3983 that is a legal constant. We really should not
3984 be using this function, because it is a part of
3985 the back-end. Instead, the expression should
3986 already have been turned into ERROR_MARK_NODE. */
3989 {
3992 }
3995 }
3997 /* Handle scalar types, including conversions. */
4001 {
4002 /* Note that convert_for_assignment calls default_conversion
4003 for arrays and functions. We must not call it in the
4004 case where inside_init is a null pointer constant. */
4005 inside_init
4010 {
4013 }
4016 {
4019 }
4022 }
4024 /* Come here only for records and arrays. */
4027 {
4030 }
4034 }
4035 \f
4036 /* Handle initializers that use braces. */
4038 /* Type of object we are accumulating a constructor for.
4039 This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE. */
4042 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4043 left to fill. */
4046 /* For an ARRAY_TYPE, this is the specified index
4047 at which to store the next element we get. */
4050 /* For an ARRAY_TYPE, this is the maximum index. */
4053 /* For a RECORD_TYPE, this is the first field not yet written out. */
4056 /* For an ARRAY_TYPE, this is the index of the first element
4057 not yet written out. */
4060 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4061 This is so we can generate gaps between fields, when appropriate. */
4064 /* If we are saving up the elements rather than allocating them,
4065 this is the list of elements so far (in reverse order,
4066 most recent first). */
4069 /* 1 if constructor should be incrementally stored into a constructor chain,
4070 0 if all the elements should be kept in AVL tree. */
4073 /* 1 if so far this constructor's elements are all compile-time constants. */
4076 /* 1 if so far this constructor's elements are all valid address constants. */
4079 /* 1 if this constructor is erroneous so far. */
4082 /* Structure for managing pending initializer elements, organized as an
4083 AVL tree. */
4085 struct init_node
4086 {
4090 tree purpose;
4091 tree value;
4092 };
4094 /* Tree of pending elements at this constructor level.
4095 These are elements encountered out of order
4096 which belong at places we haven't reached yet in actually
4097 writing the output.
4098 Will never hold tree nodes across GC runs. */
4101 /* The SPELLING_DEPTH of this constructor. */
4104 /* 0 if implicitly pushing constructor levels is allowed. */
4110 /* DECL node for which an initializer is being read.
4111 0 means we are reading a constructor expression
4112 such as (struct foo) {...}. */
4115 /* Nonzero if this is an initializer for a top-level decl. */
4118 /* Nonzero if there were any member designators in this initializer. */
4121 /* Nesting depth of designator list. */
4124 /* Nonzero if there were diagnosed errors in this designator list. */
4127 \f
4128 /* This stack has a level for each implicit or explicit level of
4129 structuring in the initializer, including the outermost one. It
4130 saves the values of most of the variables above. */
4134 struct constructor_stack
4135 {
4137 tree type;
4138 tree fields;
4139 tree index;
4140 tree max_index;
4141 tree unfilled_index;
4142 tree unfilled_fields;
4143 tree bit_index;
4144 tree elements;
4148 /* If nonzero, this value should replace the entire
4149 constructor at this level. */
4150 tree replacement_value;
4159 };
4163 /* This stack represents designators from some range designator up to
4164 the last designator in the list. */
4166 struct constructor_range_stack
4167 {
4170 tree range_start;
4171 tree index;
4172 tree range_end;
4173 tree fields;
4174 };
4178 /* This stack records separate initializers that are nested.
4179 Nested initializers can't happen in ANSI C, but GNU C allows them
4180 in cases like { ... (struct foo) { ... } ... }. */
4182 struct initializer_stack
4183 {
4185 tree decl;
4188 tree elements;
4195 };
4198 \f
4199 /* Prepare to parse and output the initializer for variable DECL. */
4201 void
4203 {
4225 {
4227 require_constant_elements
4229 /* For a scalar, you can always use any value to initialize,
4230 even within braces. */
4236 }
4237 else
4238 {
4242 }
4255 }
4257 void
4259 {
4262 /* Free the whole constructor stack of this initializer. */
4264 {
4268 }
4273 /* Pop back to the data of the outer initializer (if any). */
4288 }
4289 \f
4290 /* Call here when we see the initializer is surrounded by braces.
4291 This is instead of a call to push_init_level;
4292 it is matched by a call to pop_init_level.
4294 TYPE is the type to initialize, for a constructor expression.
4295 For an initializer for a decl, TYPE is zero. */
4297 void
4299 {
4343 {
4345 /* Skip any nameless bit fields at the beginning. */
4352 }
4354 {
4356 {
4357 constructor_max_index
4360 /* Detect non-empty initializations of zero-length arrays. */
4365 /* constructor_max_index needs to be an INTEGER_CST. Attempts
4366 to initialize VLAs will cause a proper error; avoid tree
4367 checking errors as well by setting a safe value. */
4372 constructor_index
4375 }
4376 else
4380 }
4382 {
4383 /* Vectors are like simple fixed-size arrays. */
4384 constructor_max_index =
4388 }
4389 else
4390 {
4391 /* Handle the case of int x = {5}; */
4394 }
4395 }
4396 \f
4397 /* Push down into a subobject, for initialization.
4398 If this is for an explicit set of braces, IMPLICIT is 0.
4399 If it is because the next element belongs at a lower level,
4400 IMPLICIT is 1 (or 2 if the push is because of designator list). */
4402 void
4404 {
4408 /* If we've exhausted any levels that didn't have braces,
4409 pop them now. */
4411 {
4417 && constructor_max_index
4420 else
4422 }
4424 /* Unless this is an explicit brace, we need to preserve previous
4425 content if any. */
4427 {
4434 }
4467 {
4472 }
4474 /* Don't die if an entire brace-pair level is superfluous
4475 in the containing level. */
4477 ;
4480 {
4481 /* Don't die if there are extra init elts at the end. */
4484 else
4485 {
4488 constructor_depth++;
4489 }
4490 }
4492 {
4495 constructor_depth++;
4496 }
4499 {
4504 }
4507 {
4515 }
4518 {
4521 }
4525 {
4527 /* Skip any nameless bit fields at the beginning. */
4534 }
4536 {
4537 /* Vectors are like simple fixed-size arrays. */
4538 constructor_max_index =
4542 }
4544 {
4546 {
4547 constructor_max_index
4550 /* Detect non-empty initializations of zero-length arrays. */
4555 /* constructor_max_index needs to be an INTEGER_CST. Attempts
4556 to initialize VLAs will cause a proper error; avoid tree
4557 checking errors as well by setting a safe value. */
4562 constructor_index
4565 }
4566 else
4571 {
4572 /* We need to split the char/wchar array into individual
4573 characters, so that we don't have to special case it
4574 everywhere. */
4576 }
4577 }
4578 else
4579 {
4583 }
4584 }
4586 /* At the end of an implicit or explicit brace level,
4587 finish up that level of constructor.
4588 If we were outputting the elements as they are read, return 0
4589 from inner levels (process_init_element ignores that),
4590 but return error_mark_node from the outermost level
4591 (that's what we want to put in DECL_INITIAL).
4592 Otherwise, return a CONSTRUCTOR expression. */
4594 tree
4596 {
4601 {
4602 /* When we come to an explicit close brace,
4603 pop any inner levels that didn't have explicit braces. */
4609 }
4613 /* Error for initializing a flexible array member, or a zero-length
4614 array member in an inappropriate context. */
4619 {
4620 /* Silently discard empty initializations. The parser will
4621 already have pedwarned for empty brackets. */
4625 {
4631 /* We have already issued an error message for the existence
4632 of a flexible array member not at the end of the structure.
4633 Discard the initializer so that we do not abort later. */
4636 }
4637 else
4638 /* Zero-length arrays are no longer special, so we should no longer
4639 get here. */
4641 }
4643 /* Warn when some struct elements are implicitly initialized to zero. */
4645 && constructor_type
4648 {
4649 /* Do not warn for flexible array members or zero-length arrays. */
4655 /* Do not warn if this level of the initializer uses member
4656 designators; it is likely to be deliberate. */
4658 {
4662 }
4663 }
4665 /* Now output all pending elements. */
4669 /* Pad out the end of the structure. */
4671 /* If this closes a superfluous brace pair,
4672 just pass out the element between them. */
4675 ;
4680 {
4681 /* A nonincremental scalar initializer--just return
4682 the element, after verifying there is just one. */
4684 {
4688 }
4690 {
4693 }
4694 else
4696 }
4697 else
4698 {
4701 else
4702 {
4709 }
4710 }
4735 {
4739 }
4741 }
4743 /* Common handling for both array range and field name designators.
4744 ARRAY argument is nonzero for array ranges. Returns zero for success. */
4746 static int
4748 {
4749 tree subtype;
4752 /* Don't die if an entire brace-pair level is superfluous
4753 in the containing level. */
4757 /* If there were errors in this designator list already, bail out silently. */
4762 {
4766 /* Designator list starts at the level of closest explicit
4767 braces. */
4772 }
4775 {
4778 }
4782 {
4786 }
4788 {
4790 }
4791 else
4796 {
4799 }
4801 {
4804 }
4809 }
4811 /* If there are range designators in designator list, push a new designator
4812 to constructor_range_stack. RANGE_END is end of such stack range or
4813 NULL_TREE if there is no range designator at this level. */
4815 static void
4817 {
4831 }
4833 /* Within an array initializer, specify the next index to be initialized.
4834 FIRST is that index. If LAST is nonzero, then initialize a range
4835 of indices, running from FIRST through LAST. */
4837 void
4839 {
4871 else
4872 {
4876 {
4880 {
4883 }
4884 else
4885 {
4889 {
4892 }
4893 }
4894 }
4896 designator_depth++;
4900 }
4901 }
4903 /* Within a struct initializer, specify the next field to be initialized. */
4905 void
4907 {
4908 tree tail;
4917 {
4920 }
4924 {
4927 }
4932 else
4933 {
4935 designator_depth++;
4939 }
4940 }
4941 \f
4942 /* Add a new initializer to the tree of pending initializers. PURPOSE
4943 identifies the initializer, either array index or field in a structure.
4944 VALUE is the value of that index or field. */
4946 static void
4948 {
4955 {
4957 {
4963 else
4964 {
4969 }
4970 }
4971 }
4972 else
4973 {
4974 tree bitpos;
4978 {
4984 else
4985 {
4990 }
4991 }
4992 }
5005 {
5009 {
5013 {
5015 {
5016 /* L rotation. */
5029 {
5032 else
5034 }
5035 else
5037 }
5038 else
5039 {
5040 /* LR rotation. */
5062 {
5065 else
5067 }
5068 else
5070 }
5072 }
5073 else
5074 {
5075 /* p->balance == +1; growth of left side balances the node. */
5078 }
5079 }
5081 {
5083 /* Growth propagation from right side. */
5086 {
5088 {
5089 /* R rotation. */
5102 {
5105 else
5107 }
5108 else
5110 }
5112 {
5113 /* RL rotation */
5135 {
5138 else
5140 }
5141 else
5143 }
5145 }
5146 else
5147 {
5148 /* p->balance == -1; growth of right side balances the node. */
5151 }
5152 }
5156 }
5157 }
5159 /* Build AVL tree from a sorted chain. */
5161 static void
5163 {
5164 tree chain;
5174 {
5176 /* Skip any nameless bit fields at the beginning. */
5182 }
5184 {
5186 constructor_unfilled_index
5189 else
5191 }
5193 }
5195 /* Build AVL tree from a string constant. */
5197 static void
5199 {
5214 else
5225 {
5227 {
5230 }
5231 else
5232 {
5236 {
5239 else
5244 }
5245 }
5248 {
5251 {
5253 {
5256 }
5257 }
5259 {
5262 }
5267 }
5272 }
5275 }
5277 /* Return value of FIELD in pending initializer or zero if the field was
5278 not initialized yet. */
5280 static tree
5282 {
5286 {
5293 {
5298 else
5300 }
5301 }
5303 {
5307 && (!constructor_unfilled_fields
5314 {
5319 else
5321 }
5322 }
5324 {
5328 }
5330 }
5332 /* "Output" the next constructor element.
5333 At top level, really output it to assembler code now.
5334 Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
5335 TYPE is the data type that the containing data type wants here.
5336 FIELD is the field (a FIELD_DECL) or the index that this element fills.
5338 PENDING if non-nil means output pending elements that belong
5339 right after this element. (PENDING is normally 1;
5340 it is 0 while outputting pending elements, to avoid recursion.) */
5342 static void
5344 {
5346 {
5349 }
5361 {
5362 /* As an extension, allow initializing objects with static storage
5363 duration with compound literals (which are then treated just as
5364 the brace enclosed list they contain). */
5367 }
5381 {
5384 }
5389 /* If this field is empty (and not at the end of structure),
5390 don't do anything other than checking the initializer. */
5401 {
5404 }
5406 /* If this element doesn't come next in sequence,
5407 put it on constructor_pending_elts. */
5409 && (!constructor_incremental
5411 {
5418 }
5420 && (!constructor_incremental
5422 {
5423 /* We do this for records but not for unions. In a union,
5424 no matter which field is specified, it can be initialized
5425 right away since it starts at the beginning of the union. */
5427 {
5430 else
5431 {
5439 }
5440 }
5444 }
5447 {
5451 /* We can have just one union field set. */
5453 }
5455 /* Otherwise, output this element either to
5456 constructor_elements or to the assembler file. */
5460 constructor_elements
5463 /* Advance the variable that indicates sequential elements output. */
5465 constructor_unfilled_index
5467 bitsize_one_node);
5469 {
5470 constructor_unfilled_fields
5473 /* Skip any nameless bit fields. */
5477 constructor_unfilled_fields =
5479 }
5483 /* Now output any pending elements which have become next. */
5486 }
5488 /* Output any pending elements which have become next.
5489 As we output elements, constructor_unfilled_{fields,index}
5490 advances, which may cause other elements to become next;
5491 if so, they too are output.
5493 If ALL is 0, we return when there are
5494 no more pending elements to output now.
5496 If ALL is 1, we output space as necessary so that
5497 we can output all the pending elements. */
5499 static void
5501 {
5503 tree next;
5505 retry:
5507 /* Look through the whole pending tree.
5508 If we find an element that should be output now,
5509 output it. Otherwise, set NEXT to the element
5510 that comes first among those still pending. */
5514 {
5516 {
5518 constructor_unfilled_index))
5524 {
5525 /* Advance to the next smaller node. */
5528 else
5529 {
5530 /* We have reached the smallest node bigger than the
5531 current unfilled index. Fill the space first. */
5534 }
5535 }
5536 else
5537 {
5538 /* Advance to the next bigger node. */
5541 else
5542 {
5543 /* We have reached the biggest node in a subtree. Find
5544 the parent of it, which is the next bigger node. */
5550 {
5553 }
5554 }
5555 }
5556 }
5559 {
5562 /* If the current record is complete we are done. */
5568 /* We can't compare fields here because there might be empty
5569 fields in between. */
5571 {
5575 }
5577 {
5578 /* Advance to the next smaller node. */
5581 else
5582 {
5583 /* We have reached the smallest node bigger than the
5584 current unfilled field. Fill the space first. */
5587 }
5588 }
5589 else
5590 {
5591 /* Advance to the next bigger node. */
5594 else
5595 {
5596 /* We have reached the biggest node in a subtree. Find
5597 the parent of it, which is the next bigger node. */
5604 {
5607 }
5608 }
5609 }
5610 }
5611 }
5613 /* Ordinarily return, but not if we want to output all
5614 and there are elements left. */
5618 /* If it's not incremental, just skip over the gap, so that after
5619 jumping to retry we will output the next successive element. */
5626 /* ELT now points to the node in the pending tree with the next
5627 initializer to output. */
5629 }
5630 \f
5631 /* Add one non-braced element to the current constructor level.
5632 This adjusts the current position within the constructor's type.
5633 This may also start or terminate implicit levels
5634 to handle a partly-braced initializer.
5636 Once this has found the correct level for the new element,
5637 it calls output_init_element. */
5639 void
5641 {
5648 /* Handle superfluous braces around string cst as in
5649 char x[] = {"foo"}; */
5651 && constructor_type
5655 {
5660 }
5663 {
5666 }
5668 /* Ignore elements of a brace group if it is entirely superfluous
5669 and has already been diagnosed. */
5673 /* If we've exhausted any levels that didn't have braces,
5674 pop them now. */
5676 {
5684 constructor_index)))
5686 else
5688 }
5690 /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once. */
5692 {
5693 /* If value is a compound literal and we'll be just using its
5694 content, don't put it into a SAVE_EXPR. */
5696 || !require_constant_value
5699 }
5702 {
5704 {
5705 tree fieldtype;
5709 {
5712 }
5719 /* Error for non-static initialization of a flexible array member. */
5721 && !require_constant_value
5724 {
5727 }
5729 /* Accept a string constant to initialize a subarray. */
5735 /* Otherwise, if we have come to a subaggregate,
5736 and we don't have an element of its type, push into it. */
5742 {
5745 }
5748 {
5752 }
5753 else
5754 /* Do the bookkeeping for an element that was
5755 directly output as a constructor. */
5756 {
5757 /* For a record, keep track of end position of last field. */
5759 constructor_bit_index
5764 /* If the current field was the first one not yet written out,
5765 it isn't now, so update. */
5767 {
5769 /* Skip any nameless bit fields. */
5773 constructor_unfilled_fields =
5775 }
5776 }
5779 /* Skip any nameless bit fields at the beginning. */
5784 }
5786 {
5787 tree fieldtype;
5791 {
5794 }
5801 /* Warn that traditional C rejects initialization of unions.
5802 We skip the warning if the value is zero. This is done
5803 under the assumption that the zero initializer in user
5804 code appears conditioned on e.g. __STDC__ to avoid
5805 "missing initializer" warnings and relies on default
5806 initialization to zero in the traditional C case.
5807 We also skip the warning if the initializer is designated,
5808 again on the assumption that this must be conditional on
5809 __STDC__ anyway (and we've already complained about the
5810 member-designator already). */
5815 /* Accept a string constant to initialize a subarray. */
5821 /* Otherwise, if we have come to a subaggregate,
5822 and we don't have an element of its type, push into it. */
5828 {
5831 }
5834 {
5838 }
5839 else
5840 /* Do the bookkeeping for an element that was
5841 directly output as a constructor. */
5842 {
5845 }
5848 }
5850 {
5854 /* Accept a string constant to initialize a subarray. */
5860 /* Otherwise, if we have come to a subaggregate,
5861 and we don't have an element of its type, push into it. */
5867 {
5870 }
5875 {
5878 }
5880 /* Now output the actual element. */
5882 {
5886 }
5888 constructor_index
5892 /* If we are doing the bookkeeping for an element that was
5893 directly output as a constructor, we must update
5894 constructor_unfilled_index. */
5896 }
5898 {
5901 /* Do a basic check of initializer size. Note that vectors
5902 always have a fixed size derived from their type. */
5904 {
5907 }
5909 /* Now output the actual element. */
5913 constructor_index
5917 /* If we are doing the bookkeeping for an element that was
5918 directly output as a constructor, we must update
5919 constructor_unfilled_index. */
5921 }
5923 /* Handle the sole element allowed in a braced initializer
5924 for a scalar variable. */
5926 {
5929 }
5930 else
5931 {
5935 }
5937 /* Handle range initializers either at this level or anywhere higher
5938 in the designator stack. */
5940 {
5947 {
5951 }
5955 {
5959 }
5966 {
5970 {
5973 }
5981 }
5986 }
5989 }
5992 }
5993 \f
5994 /* Build a simple asm-statement, from one string literal. */
5995 tree
5997 {
6004 {
6005 tree stmt;
6007 /* Simple asm statements are treated as volatile. */
6012 }
6016 }
6018 /* Build an asm-statement, whose components are a CV_QUALIFIER, a
6019 STRING, some OUTPUTS, some INPUTS, and some CLOBBERS. */
6021 tree
6023 tree clobbers)
6024 {
6025 tree tail;
6028 {
6031 }
6035 {
6039 }
6041 /* We can remove output conversions that change the type,
6042 but not the mode. */
6044 {
6050 /* Allow conversions as LHS here. build_modify_expr as called below
6051 will do the right thing with them. */
6062 }
6064 /* Remove output conversions that change the type but not the mode. */
6066 {
6070 }
6072 /* Perform default conversions on array and function inputs.
6073 Don't do this for other types as it would screw up operands
6074 expected to be in memory. */
6080 }
6082 /* Expand an ASM statement with operands, handling output operands
6083 that are not variables or INDIRECT_REFS by transforming such
6084 cases into cases that expand_asm_operands can handle.
6086 Arguments are same as for expand_asm_operands. */
6088 void
6091 {
6094 /* o[I] is the place that output number I should be written. */
6096 tree tail;
6098 /* Record the contents of OUTPUTS before it is modified. */
6100 {
6104 }
6106 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
6107 OUTPUTS some trees for where the values were actually stored. */
6110 /* Copy all the intermediate outputs into the specified outputs. */
6112 {
6114 {
6119 /* Restore the original value so that it's correct the next
6120 time we expand this function. */
6122 }
6123 /* Detect modification of read-only values.
6124 (Otherwise done by build_modify_expr.) */
6125 else
6126 {
6134 }
6135 }
6137 /* Those MODIFY_EXPRs could do autoincrements. */
6139 }
6140 \f
6141 /* Expand a C `return' statement.
6142 RETVAL is the expression for what to return,
6143 or a null pointer for `return;' with no value. */
6145 tree
6147 {
6154 {
6159 }
6161 {
6165 }
6166 else
6167 {
6171 tree inner;
6179 /* Strip any conversions, additions, and subtractions, and see if
6180 we are returning the address of a local variable. Warn if so. */
6182 {
6184 {
6191 /* If the second operand of the MINUS_EXPR has a pointer
6192 type (or is converted from it), this may be valid, so
6193 don't give a warning. */
6194 {
6208 }
6225 }
6228 }
6231 }
6234 }
6235 \f
6237 /* The SWITCH_STMT being built. */
6238 tree switch_stmt;
6239 /* A splay-tree mapping the low element of a case range to the high
6240 element, or NULL_TREE if there is no high element. Used to
6241 determine whether or not a new case label duplicates an old case
6242 label. We need a tree, rather than simply a hash table, because
6243 of the GNU case range extension. */
6244 splay_tree cases;
6245 /* The next node on the stack. */
6247 };
6249 /* A stack of the currently active switch statements. The innermost
6250 switch statement is on the top of the stack. There is no need to
6251 mark the stack for garbage collection because it is only active
6252 during the processing of the body of a function, and we never
6253 collect at that point. */
6257 /* Start a C switch statement, testing expression EXP. Return the new
6258 SWITCH_STMT. */
6260 tree
6262 {
6268 {
6274 {
6277 }
6278 else
6279 {
6289 }
6290 }
6292 /* Add this new SWITCH_STMT to the stack. */
6300 }
6302 /* Process a case label. */
6304 tree
6306 {
6310 {
6319 {
6320 /* Attach the first case label to the SWITCH_BODY. */
6323 }
6324 }
6327 else
6331 }
6333 /* Finish the switch statement. */
6335 void
6337 {
6340 /* Rechain the next statements to the SWITCH_STMT. */
6343 /* Pop the stack. */
6347 }
6349 /* Build a binary-operation expression without default conversions.
6350 CODE is the kind of expression to build.
6351 This function differs from `build' in several ways:
6352 the data type of the result is computed and recorded in it,
6353 warnings are generated if arg data types are invalid,
6354 special handling for addition and subtraction of pointers is known,
6355 and some optimization is done (operations on narrow ints
6356 are done in the narrower type when that gives the same result).
6357 Constant folding is also done before the result is returned.
6359 Note that the operands will never have enumeral types, or function
6360 or array types, because either they will have the default conversions
6361 performed or they have both just been converted to some other type in which
6362 the arithmetic is to be done. */
6364 tree
6367 {
6372 /* Expression code to give to the expression when it is built.
6373 Normally this is CODE, which is what the caller asked for,
6374 but in some special cases we change it. */
6377 /* Data type in which the computation is to be performed.
6378 In the simplest cases this is the common type of the arguments. */
6381 /* Nonzero means operands have already been type-converted
6382 in whatever way is necessary.
6383 Zero means they need to be converted to RESULT_TYPE. */
6386 /* Nonzero means create the expression with this type, rather than
6387 RESULT_TYPE. */
6390 /* Nonzero means after finally constructing the expression
6391 convert it to this type. */
6394 /* Nonzero if this is an operation like MIN or MAX which can
6395 safely be computed in short if both args are promoted shorts.
6396 Also implies COMMON.
6397 -1 indicates a bitwise operation; this makes a difference
6398 in the exact conditions for when it is safe to do the operation
6399 in a narrower mode. */
6402 /* Nonzero if this is a comparison operation;
6403 if both args are promoted shorts, compare the original shorts.
6404 Also implies COMMON. */
6407 /* Nonzero if this is a right-shift operation, which can be computed on the
6408 original short and then promoted if the operand is a promoted short. */
6411 /* Nonzero means set RESULT_TYPE to the common type of the args. */
6415 {
6418 }
6419 else
6420 {
6423 }
6428 /* The expression codes of the data types of the arguments tell us
6429 whether the arguments are integers, floating, pointers, etc. */
6433 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
6437 /* If an error was already reported for one of the arguments,
6438 avoid reporting another error. */
6444 {
6446 /* Handle the pointer + int case. */
6451 else
6456 /* Subtraction of two similar pointers.
6457 We must subtract them as integers, then divide by object size. */
6461 /* Handle pointer minus int. Just like pointer plus int. */
6464 else
6477 /* Floating point division by zero is a legitimate way to obtain
6478 infinities and NaNs. */
6486 {
6489 else
6490 /* Although it would be tempting to shorten always here, that
6491 loses on some targets, since the modulo instruction is
6492 undefined if the quotient can't be represented in the
6493 computation mode. We shorten only if unsigned or if
6494 dividing by something we know != -1. */
6499 }
6517 {
6518 /* Although it would be tempting to shorten always here, that loses
6519 on some targets, since the modulo instruction is undefined if the
6520 quotient can't be represented in the computation mode. We shorten
6521 only if unsigned or if dividing by something we know != -1. */
6526 }
6538 {
6539 /* Result of these operations is always an int,
6540 but that does not mean the operands should be
6541 converted to ints! */
6546 }
6549 /* Shift operations: result has same type as first operand;
6550 always convert second operand to int.
6551 Also set SHORT_SHIFT if shifting rightward. */
6555 {
6557 {
6560 else
6561 {
6567 }
6568 }
6570 /* Use the type of the value to be shifted. */
6572 /* Convert the shift-count to an integer, regardless of size
6573 of value being shifted. */
6576 /* Avoid converting op1 to result_type later. */
6578 }
6583 {
6585 {
6591 }
6593 /* Use the type of the value to be shifted. */
6595 /* Convert the shift-count to an integer, regardless of size
6596 of value being shifted. */
6599 /* Avoid converting op1 to result_type later. */
6601 }
6607 {
6609 {
6614 }
6616 /* Use the type of the value to be shifted. */
6618 /* Convert the shift-count to an integer, regardless of size
6619 of value being shifted. */
6622 /* Avoid converting op1 to result_type later. */
6624 }
6631 /* Result of comparison is always int,
6632 but don't convert the args to int! */
6642 {
6645 /* Anything compares with void *. void * compares with anything.
6646 Otherwise, the targets must be compatible
6647 and both must be object or both incomplete. */
6651 {
6652 /* op0 != orig_op0 detects the case of something
6653 whose value is 0 but which isn't a valid null ptr const. */
6657 }
6659 {
6663 }
6664 else
6669 }
6677 {
6680 }
6682 {
6685 }
6694 {
6696 {
6701 }
6702 else
6703 {
6706 }
6707 }
6719 {
6721 {
6729 }
6730 else
6731 {
6734 }
6735 }
6738 {
6742 }
6745 {
6749 }
6751 {
6754 }
6756 {
6759 }
6771 {
6774 }
6780 }
6787 &&
6790 {
6796 /* For certain operations (which identify themselves by shorten != 0)
6797 if both args were extended from the same smaller type,
6798 do the arithmetic in that type and then extend.
6800 shorten !=0 and !=1 indicates a bitwise operation.
6801 For them, this optimization is safe only if
6802 both args are zero-extended or both are sign-extended.
6803 Otherwise, we might change the result.
6804 Eg, (short)-1 | (unsigned short)-1 is (int)-1
6805 but calculated in (unsigned short) it would be (unsigned short)-1. */
6808 {
6812 /* UNS is 1 if the operation to be done is an unsigned one. */
6814 tree type;
6818 /* Handle the case that OP0 (or OP1) does not *contain* a conversion
6819 but it *requires* conversion to FINAL_TYPE. */
6830 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */
6832 /* For bitwise operations, signedness of nominal type
6833 does not matter. Consider only how operands were extended. */
6837 /* Note that in all three cases below we refrain from optimizing
6838 an unsigned operation on sign-extended args.
6839 That would not be valid. */
6841 /* Both args variable: if both extended in same way
6842 from same width, do it in that width.
6843 Do it unsigned if args were zero-extended. */
6850 result_type
6851 = c_common_signed_or_unsigned_type
6857 && (type
6866 && (type
6871 }
6873 /* Shifts can be shortened if shifting right. */
6876 {
6886 /* We can shorten only if the shift count is less than the
6887 number of bits in the smaller type size. */
6889 /* We cannot drop an unsigned shift after sign-extension. */
6891 {
6892 /* Do an unsigned shift if the operand was zero-extended. */
6893 result_type
6896 /* Convert value-to-be-shifted to that type. */
6900 }
6901 }
6903 /* Comparison operations are shortened too but differently.
6904 They identify themselves by setting short_compare = 1. */
6907 {
6908 /* Don't write &op0, etc., because that would prevent op0
6909 from being kept in a register.
6910 Instead, make copies of the our local variables and
6911 pass the copies by reference, then copy them back afterward. */
6914 tree val
6925 {
6937 /* Give warnings for comparisons between signed and unsigned
6938 quantities that may fail.
6940 Do the checking based on the original operand trees, so that
6941 casts will be considered, but default promotions won't be.
6943 Do not warn if the comparison is being done in a signed type,
6944 since the signed type will only be chosen if it can represent
6945 all the values of the unsigned type. */
6948 /* Do not warn if both operands are the same signedness. */
6951 else
6952 {
6957 else
6960 /* Do not warn if the signed quantity is an
6961 unsuffixed integer literal (or some static
6962 constant expression involving such literals or a
6963 conditional expression involving such literals)
6964 and it is non-negative. */
6967 /* Do not warn if the comparison is an equality operation,
6968 the unsigned quantity is an integral constant, and it
6969 would fit in the result if the result were signed. */
6972 && int_fits_type_p
6975 /* Do not warn if the unsigned quantity is an enumeration
6976 constant and its maximum value would fit in the result
6977 if the result were signed. */
6980 && int_fits_type_p
6984 else
6986 }
6988 /* Warn if two unsigned values are being compared in a size
6989 larger than their original size, and one (and only one) is the
6990 result of a `~' operator. This comparison will always fail.
6992 Also warn if one operand is a constant, and the constant
6993 does not have all bits set that are set in the ~ operand
6994 when it is extended. */
6998 {
7002 else
7007 {
7008 tree primop;
7013 {
7017 }
7018 else
7019 {
7023 }
7028 {
7032 }
7033 }
7040 }
7041 }
7042 }
7043 }
7045 /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
7046 If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
7047 Then the expression will be built.
7048 It will be given type FINAL_TYPE if that is nonzero;
7049 otherwise, it will be given type RESULT_TYPE. */
7052 {
7055 }
7058 {
7063 }
7068 {
7070 tree folded;
7072 /* Treat expressions in initializers specially as they can't trap. */
7080 }
7081 }