| blob | a3cd563e531f6068d27b166c0171bc1f7c108724 |
1 /* Build expressions with type checking for C compiler.
2 Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 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 the Free
20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
21 02110-1301, USA. */
24 /* This file is part of the C front end.
25 It contains routines to build C expressions given their operands,
26 including computing the types of the result, C-specific error checks,
27 and some optimization. */
49 /* Possible cases of implicit bad conversions. Used to select
50 diagnostic messages in convert_for_assignment. */
52 ic_argpass,
53 ic_argpass_nonproto,
54 ic_assign,
55 ic_init,
56 ic_return
57 };
59 /* The level of nesting inside "__alignof__". */
62 /* The level of nesting inside "sizeof". */
65 /* The level of nesting inside "typeof". */
71 /* Nonzero if we've already printed a "missing braces around initializer"
72 message within this initializer. */
110 \f
111 /* Return true if EXP is a null pointer constant, false otherwise. */
113 static bool
115 {
116 /* This should really operate on c_expr structures, but they aren't
117 yet available everywhere required. */
126 }
131 tree t1;
132 tree t2;
133 /* The return value of tagged_types_tu_compatible_p if we had seen
134 these two types already. */
136 };
141 /* Do `exp = require_complete_type (exp);' to make sure exp
142 does not have an incomplete type. (That includes void types.) */
144 tree
146 {
152 /* First, detect a valid value with a complete type. */
158 }
160 /* Print an error message for invalid use of an incomplete type.
161 VALUE is the expression that was used (or 0 if that isn't known)
162 and TYPE is the type that was invalid. */
164 void
166 {
169 /* Avoid duplicate error message. */
176 else
177 {
178 retry:
179 /* We must print an error message. Be clever about what it says. */
182 {
201 {
203 {
206 }
209 }
215 }
220 else
221 /* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL. */
223 }
224 }
226 /* Given a type, apply default promotions wrt unnamed function
227 arguments and return the new type. */
229 tree
231 {
236 {
237 /* Preserve unsignedness if not really getting any wider. */
242 }
245 }
247 /* Return a variant of TYPE which has all the type qualifiers of LIKE
248 as well as those of TYPE. */
250 static tree
252 {
255 }
257 /* Return true iff the given tree T is a variable length array. */
259 bool
261 {
266 }
267 \f
268 /* Return the composite type of two compatible types.
270 We assume that comptypes has already been done and returned
271 nonzero; if that isn't so, this may crash. In particular, we
272 assume that qualifiers match. */
274 tree
276 {
279 tree attributes;
281 /* Save time if the two types are the same. */
285 /* If one type is nonsense, use the other. */
294 /* Merge the attributes. */
297 /* If one is an enumerated type and the other is the compatible
298 integer type, the composite type might be either of the two
299 (DR#013 question 3). For consistency, use the enumerated type as
300 the composite type. */
310 {
312 /* For two pointers, do this recursively on the target type. */
313 {
320 }
323 {
326 tree unqual_elt;
332 /* We should not have any type quals on arrays at all. */
338 d1_variable = (!d1_zero
341 d2_variable = (!d2_zero
347 /* Save space: see if the result is identical to one of the args. */
360 /* Merge the element types, and have a size if either arg has
361 one. We may have qualifiers on the element types. To set
362 up TYPE_MAIN_VARIANT correctly, we need to form the
363 composite of the unqualified types and add the qualifiers
364 back at the end. */
369 && (d2_variable
370 || d2_zero
372 ? t1
376 }
382 {
383 /* Try harder not to create a new aggregate type. */
388 }
392 /* Function types: prefer the one that specified arg types.
393 If both do, merge the arg types. Also merge the return types. */
394 {
402 /* Save space: see if the result is identical to one of the args. */
408 /* Simple way if one arg fails to specify argument types. */
410 {
414 }
416 {
420 }
422 /* If both args specify argument types, we must merge the two
423 lists, argument by argument. */
424 /* Tell global_bindings_p to return false so that variable_size
425 doesn't die on VLAs in parameter types. */
438 {
439 /* A null type means arg type is not specified.
440 Take whatever the other function type has. */
442 {
445 }
447 {
450 }
452 /* Given wait (union {union wait *u; int *i} *)
453 and wait (union wait *),
454 prefer union wait * as type of parm. */
457 {
458 tree memb;
465 {
471 {
477 }
478 }
479 }
482 {
483 tree memb;
490 {
496 {
502 }
503 }
504 }
506 parm_done: ;
507 }
512 /* ... falls through ... */
513 }
517 }
519 }
521 /* Return the type of a conditional expression between pointers to
522 possibly differently qualified versions of compatible types.
524 We assume that comp_target_types has already been done and returned
525 nonzero; if that isn't so, this may crash. */
527 static tree
529 {
530 tree attributes;
533 tree target;
535 /* Save time if the two types are the same. */
539 /* If one type is nonsense, use the other. */
548 /* Merge the attributes. */
551 /* Find the composite type of the target types, and combine the
552 qualifiers of the two types' targets. Do not lose qualifiers on
553 array element types by taking the TYPE_MAIN_VARIANT. */
566 }
568 /* Return the common type for two arithmetic types under the usual
569 arithmetic conversions. The default conversions have already been
570 applied, and enumerated types converted to their compatible integer
571 types. The resulting type is unqualified and has no attributes.
573 This is the type for the result of most arithmetic operations
574 if the operands have the given two types. */
576 static tree
578 {
582 /* If one type is nonsense, use the other. */
600 /* Save time if the two types are the same. */
612 /* When one operand is a decimal float type, the other operand cannot be
613 a generic float type or a complex type. We also disallow vector types
614 here. */
617 {
619 {
622 }
624 {
627 }
629 {
632 }
633 }
635 /* If one type is a vector type, return that type. (How the usual
636 arithmetic conversions apply to the vector types extension is not
637 precisely specified.) */
644 /* If one type is complex, form the common type of the non-complex
645 components, then make that complex. Use T1 or T2 if it is the
646 required type. */
648 {
657 else
659 }
661 /* If only one is real, use it as the result. */
669 /* If both are real and either are decimal floating point types, use
670 the decimal floating point type with the greater precision. */
673 {
683 }
685 /* Both real or both integers; use the one with greater precision. */
692 /* Same precision. Prefer long longs to longs to ints when the
693 same precision, following the C99 rules on integer type rank
694 (which are equivalent to the C90 rules for C90 types). */
702 {
705 else
707 }
715 {
716 /* But preserve unsignedness from the other type,
717 since long cannot hold all the values of an unsigned int. */
720 else
722 }
724 /* Likewise, prefer long double to double even if same size. */
729 /* Otherwise prefer the unsigned one. */
733 else
735 }
736 \f
737 /* Wrapper around c_common_type that is used by c-common.c and other
738 front end optimizations that remove promotions. ENUMERAL_TYPEs
739 are allowed here and are converted to their compatible integer types.
740 BOOLEAN_TYPEs are allowed here and return either boolean_type_node or
741 preferably a non-Boolean type as the common type. */
742 tree
744 {
750 /* If both types are BOOLEAN_TYPE, then return boolean_type_node. */
755 /* If either type is BOOLEAN_TYPE, then return the other. */
762 }
764 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
765 or various other operations. Return 2 if they are compatible
766 but a warning may be needed if you use them together. */
768 int
770 {
778 }
779 \f
780 /* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
781 or various other operations. Return 2 if they are compatible
782 but a warning may be needed if you use them together. This
783 differs from comptypes, in that we don't free the seen types. */
785 static int
787 {
792 /* Suppress errors caused by previously reported errors. */
798 /* If either type is the internal version of sizetype, return the
799 language version. */
809 /* Enumerated types are compatible with integer types, but this is
810 not transitive: two enumerated types in the same translation unit
811 are compatible with each other only if they are the same type. */
821 /* Different classes of types can't be compatible. */
826 /* Qualifiers must match. C99 6.7.3p9 */
831 /* Allow for two different type nodes which have essentially the same
832 definition. Note that we already checked for equality of the type
833 qualifiers (just above). */
839 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
843 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
847 {
849 /* Do not remove mode or aliasing information. */
862 {
869 /* Target types must match incl. qualifiers. */
874 /* Sizes must match unless one is missing or variable. */
881 d1_variable = (!d1_zero
884 d2_variable = (!d2_zero
900 }
906 {
917 }
927 }
929 }
931 /* Return 1 if TTL and TTR are pointers to types that are equivalent,
932 ignoring their qualifiers. */
934 static int
936 {
940 /* Do not lose qualifiers on element types of array types that are
941 pointer targets by taking their TYPE_MAIN_VARIANT. */
953 }
954 \f
955 /* Subroutines of `comptypes'. */
957 /* Determine whether two trees derive from the same translation unit.
958 If the CONTEXT chain ends in a null, that tree's context is still
959 being parsed, so if two trees have context chains ending in null,
960 they're in the same translation unit. */
961 int
963 {
966 {
974 }
978 {
986 }
989 }
991 /* Allocate the seen two types, assuming that they are compatible. */
995 {
1003 /* The C standard says that two structures in different translation
1004 units are compatible with each other only if the types of their
1005 fields are compatible (among other things). We assume that they
1006 are compatible until proven otherwise when building the cache.
1007 An example where this can occur is:
1008 struct a
1009 {
1010 struct a *next;
1011 };
1012 If we are comparing this against a similar struct in another TU,
1013 and did not assume they were compatible, we end up with an infinite
1014 loop. */
1017 }
1019 /* Free the seen types until we get to TU_TIL. */
1021 static void
1023 {
1026 {
1030 }
1032 }
1034 /* Return 1 if two 'struct', 'union', or 'enum' types T1 and T2 are
1035 compatible. If the two types are not the same (which has been
1036 checked earlier), this can only happen when multiple translation
1037 units are being compiled. See C99 6.2.7 paragraph 1 for the exact
1038 rules. */
1040 static int
1042 {
1046 /* We have to verify that the tags of the types are the same. This
1047 is harder than it looks because this may be a typedef, so we have
1048 to go look at the original type. It may even be a typedef of a
1049 typedef...
1050 In the case of compiler-created builtin structs the TYPE_DECL
1051 may be a dummy, with no DECL_ORIGINAL_TYPE. Don't fault. */
1062 /* C90 didn't have the requirement that the two tags be the same. */
1066 /* C90 didn't say what happened if one or both of the types were
1067 incomplete; we choose to follow C99 rules here, which is that they
1068 are compatible. */
1073 {
1078 }
1081 {
1083 {
1085 /* Speed up the case where the type values are in the same order. */
1090 {
1092 }
1095 {
1099 {
1102 }
1103 }
1106 {
1108 }
1110 {
1113 }
1116 {
1119 }
1122 {
1126 {
1129 }
1130 }
1132 }
1135 {
1138 {
1141 }
1143 /* Speed up the common case where the fields are in the same order. */
1146 {
1155 {
1158 }
1165 {
1168 }
1169 }
1171 {
1174 }
1177 {
1183 {
1187 {
1190 }
1201 }
1203 {
1206 }
1207 }
1210 }
1213 {
1219 {
1234 }
1237 else
1240 }
1244 }
1245 }
1247 /* Return 1 if two function types F1 and F2 are compatible.
1248 If either type specifies no argument types,
1249 the other must specify a fixed number of self-promoting arg types.
1250 Otherwise, if one type specifies only the number of arguments,
1251 the other must specify that number of self-promoting arg types.
1252 Otherwise, the argument types must match. */
1254 static int
1256 {
1258 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
1266 /* 'volatile' qualifiers on a function's return type used to mean
1267 the function is noreturn. */
1283 /* An unspecified parmlist matches any specified parmlist
1284 whose argument types don't need default promotions. */
1287 {
1290 /* If one of these types comes from a non-prototype fn definition,
1291 compare that with the other type's arglist.
1292 If they don't match, ask for a warning (but no error). */
1297 }
1299 {
1306 }
1308 /* Both types have argument lists: compare them and propagate results. */
1311 }
1313 /* Check two lists of types for compatibility,
1314 returning 0 for incompatible, 1 for compatible,
1315 or 2 for compatible with warning. */
1317 static int
1319 {
1320 /* 1 if no need for warning yet, 2 if warning cause has been seen. */
1325 {
1329 /* If one list is shorter than the other,
1330 they fail to match. */
1339 /* A null pointer instead of a type
1340 means there is supposed to be an argument
1341 but nothing is specified about what type it has.
1342 So match anything that self-promotes. */
1344 {
1347 }
1349 {
1352 }
1353 /* If one of the lists has an error marker, ignore this arg. */
1356 ;
1358 {
1359 /* Allow wait (union {union wait *u; int *i} *)
1360 and wait (union wait *) to be compatible. */
1367 {
1368 tree memb;
1371 {
1378 }
1381 }
1388 {
1389 tree memb;
1392 {
1399 }
1402 }
1403 else
1405 }
1407 /* comptypes said ok, but record if it said to warn. */
1413 }
1414 }
1415 \f
1416 /* Compute the size to increment a pointer by. */
1418 static tree
1420 {
1427 {
1430 }
1432 /* Convert in case a char is more than one unit. */
1436 }
1437 \f
1438 /* Return either DECL or its known constant value (if it has one). */
1440 tree
1442 {
1444 in a place where a variable is invalid. Note that DECL_INITIAL
1445 isn't valid for a PARM_DECL. */
1452 /* This is invalid if initial value is not constant.
1453 If it has either a function call, a memory reference,
1454 or a variable, then re-evaluating it could give different results. */
1456 /* Check for cases where this is sub-optimal, even though valid. */
1460 }
1462 /* Return either DECL or its known constant value (if it has one), but
1463 return DECL if pedantic or DECL has mode BLKmode. This is for
1464 bug-compatibility with the old behavior of decl_constant_value
1465 (before GCC 3.0); every use of this function is a bug and it should
1466 be removed before GCC 3.1. It is not appropriate to use pedantic
1467 in a way that affects optimization, and BLKmode is probably not the
1468 right test for avoiding misoptimizations either. */
1470 static tree
1472 {
1473 tree ret;
1479 /* Avoid unwanted tree sharing between the initializer and current
1480 function's body where the tree can be modified e.g. by the
1481 gimplifier. */
1485 }
1487 /* Convert the array expression EXP to a pointer. */
1488 static tree
1490 {
1493 tree adr;
1495 tree ptrtype;
1510 {
1511 /* We are making an ADDR_EXPR of ptrtype. This is a valid
1512 ADDR_EXPR because it's the best way of representing what
1513 happens in C when we take the address of an array and place
1514 it in a pointer to the element type. */
1520 }
1522 /* This way is better for a COMPONENT_REF since it can
1523 simplify the offset for a component. */
1526 }
1528 /* Convert the function expression EXP to a pointer. */
1529 static tree
1531 {
1542 }
1544 /* Perform the default conversion of arrays and functions to pointers.
1545 Return the result of converting EXP. For any other expression, just
1546 return EXP after removing NOPs. */
1548 struct c_expr
1550 {
1556 {
1558 {
1566 {
1570 }
1577 {
1578 /* Before C99, non-lvalue arrays do not decay to pointers.
1579 Normally, using such an array would be invalid; but it can
1580 be used correctly inside sizeof or as a statement expression.
1581 Thus, do not give an error here; an error will result later. */
1583 }
1586 }
1596 }
1599 }
1602 /* EXP is an expression of integer type. Apply the integer promotions
1603 to it and return the promoted value. */
1605 tree
1607 {
1613 /* Normally convert enums to int,
1614 but convert wide enums to something wider. */
1616 {
1624 }
1626 /* ??? This should no longer be needed now bit-fields have their
1627 proper types. */
1630 /* If it's thinner than an int, promote it like a
1631 c_promoting_integer_type_p, otherwise leave it alone. */
1637 {
1638 /* Preserve unsignedness if not really getting any wider. */
1644 }
1647 }
1650 /* Perform default promotions for C data used in expressions.
1651 Enumeral types or short or char are converted to int.
1652 In addition, manifest constants symbols are replaced by their values. */
1654 tree
1656 {
1657 tree orig_exp;
1661 /* Functions and arrays have been converted during parsing. */
1666 /* Constants can be used directly unless they're not loadable. */
1670 /* Replace a nonvolatile const static variable with its value unless
1671 it is an array, in which case we must be sure that taking the
1672 address of the array produces consistent results. */
1674 {
1677 }
1679 /* Strip no-op conversions. */
1690 {
1693 }
1695 }
1696 \f
1697 /* Look up COMPONENT in a structure or union DECL.
1699 If the component name is not found, returns NULL_TREE. Otherwise,
1700 the return value is a TREE_LIST, with each TREE_VALUE a FIELD_DECL
1701 stepping down the chain to the component, which is in the last
1702 TREE_VALUE of the list. Normally the list is of length one, but if
1703 the component is embedded within (nested) anonymous structures or
1704 unions, the list steps down the chain to the component. */
1706 static tree
1708 {
1710 tree field;
1712 /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
1713 to the field elements. Use a binary search on this array to quickly
1714 find the element. Otherwise, do a linear search. TYPE_LANG_SPECIFIC
1715 will always be set for structures which have many elements. */
1718 {
1726 {
1731 {
1732 /* Step through all anon unions in linear fashion. */
1734 {
1738 {
1743 }
1744 }
1746 /* Entire record is only anon unions. */
1750 /* Restart the binary search, with new lower bound. */
1752 }
1758 else
1760 }
1766 }
1767 else
1768 {
1770 {
1774 {
1779 }
1783 }
1787 }
1790 }
1792 /* Make an expression to refer to the COMPONENT field of
1793 structure or union value DATUM. COMPONENT is an IDENTIFIER_NODE. */
1795 tree
1797 {
1801 tree ref;
1806 /* See if there is a field or component with name COMPONENT. */
1809 {
1811 {
1814 }
1819 {
1822 }
1824 /* Chain the COMPONENT_REFs if necessary down to the FIELD.
1825 This might be better solved in future the way the C++ front
1826 end does it - by giving the anonymous entities each a
1827 separate name and type, and then have build_component_ref
1828 recursively call itself. We can't do that here. */
1829 do
1830 {
1833 tree subtype;
1843 NULL_TREE);
1855 }
1859 }
1862 component);
1865 }
1866 \f
1867 /* Given an expression PTR for a pointer, return an expression
1868 for the value pointed to.
1869 ERRORSTRING is the name of the operator to appear in error messages. */
1871 tree
1873 {
1878 {
1883 else
1884 {
1886 tree ref;
1891 {
1894 }
1898 /* We *must* set TREE_READONLY when dereferencing a pointer to const,
1899 so that we get the proper error message if the result is used
1900 to assign to. Also, &* is supposed to be a no-op.
1901 And ANSI C seems to specify that the type of the result
1902 should be the const type. */
1903 /* A de-reference of a pointer to const is not a const. It is valid
1904 to change it via some other pointer. */
1910 }
1911 }
1915 }
1917 /* This handles expressions of the form "a[i]", which denotes
1918 an array reference.
1920 This is logically equivalent in C to *(a+i), but we may do it differently.
1921 If A is a variable or a member, we generate a primitive ARRAY_REF.
1922 This avoids forcing the array out of registers, and can work on
1923 arrays that are not lvalues (for example, members of structures returned
1924 by functions). */
1926 tree
1928 {
1936 {
1937 tree temp;
1940 {
1943 }
1948 }
1951 {
1954 }
1957 {
1960 }
1962 /* ??? Existing practice has been to warn only when the char
1963 index is syntactically the index, not for char[array]. */
1967 /* Apply default promotions *after* noticing character types. */
1973 {
1976 /* An array that is indexed by a non-constant
1977 cannot be stored in a register; we must be able to do
1978 address arithmetic on its address.
1979 Likewise an array of elements of variable size. */
1983 {
1986 }
1987 /* An array that is indexed by a constant value which is not within
1988 the array bounds cannot be stored in a register either; because we
1989 would get a crash in store_bit_field/extract_bit_field when trying
1990 to access a non-existent part of the register. */
1994 {
1997 }
2000 {
2008 }
2014 /* Array ref is const/volatile if the array elements are
2015 or if the array is. */
2024 /* This was added by rms on 16 Nov 91.
2025 It fixes vol struct foo *a; a->elts[1]
2026 in an inline function.
2027 Hope it doesn't break something else. */
2030 }
2031 else
2032 {
2043 }
2044 }
2045 \f
2046 /* Build an external reference to identifier ID. FUN indicates
2047 whether this will be used for a function call. LOC is the source
2048 location of the identifier. */
2049 tree
2051 {
2052 tree ref;
2055 /* In Objective-C, an instance variable (ivar) may be preferred to
2056 whatever lookup_name() found. */
2062 /* Implicit function declaration. */
2065 /* Don't complain about something that's already been
2066 complained about. */
2068 else
2069 {
2072 }
2085 {
2092 }
2095 {
2100 }
2106 {
2111 }
2112 /* C99 6.7.4p3: An inline definition of a function with external
2113 linkage ... shall not contain a reference to an identifier with
2114 internal linkage. */
2125 }
2127 /* Record details of decls possibly used inside sizeof or typeof. */
2128 struct maybe_used_decl
2129 {
2130 /* The decl. */
2131 tree decl;
2132 /* The level seen at (in_sizeof + in_typeof). */
2134 /* The next one at this level or above, or NULL. */
2136 };
2140 /* Record that DECL, an undefined static function reference seen
2141 inside sizeof or typeof, might be used if the operand of sizeof is
2142 a VLA type or the operand of typeof is a variably modified
2143 type. */
2145 static void
2147 {
2153 }
2155 /* Pop the stack of decls possibly used inside sizeof or typeof. If
2156 USED is false, just discard them. If it is true, mark them used
2157 (if no longer inside sizeof or typeof) or move them to the next
2158 level up (if still inside sizeof or typeof). */
2160 void
2162 {
2166 {
2168 {
2171 else
2173 }
2175 }
2178 }
2180 /* Return the result of sizeof applied to EXPR. */
2182 struct c_expr
2184 {
2187 {
2191 }
2192 else
2193 {
2197 {
2198 /* sizeof is evaluated when given a vla (C99 6.5.3.4p2). */
2200 }
2202 }
2204 }
2206 /* Return the result of sizeof applied to T, a structure for the type
2207 name passed to sizeof (rather than the type itself). */
2209 struct c_expr
2211 {
2212 tree type;
2220 }
2222 /* Build a function call to function FUNCTION with parameters PARAMS.
2223 PARAMS is a list--a chain of TREE_LIST nodes--in which the
2224 TREE_VALUE of each node is a parameter-expression.
2225 FUNCTION's data type may be a function type or a pointer-to-function. */
2227 tree
2229 {
2232 tree tem;
2237 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
2240 /* Convert anything with function type to a pointer-to-function. */
2242 {
2243 /* Implement type-directed function overloading for builtins.
2244 resolve_overloaded_builtin and targetm.resolve_overloaded_builtin
2245 handle all the type checking. The result is a complete expression
2246 that implements this function call. */
2253 }
2257 /* For Objective-C, convert any calls via a cast to OBJC_TYPE_REF
2258 expressions, like those used for ObjC messenger dispatches. */
2268 {
2271 }
2276 /* fntype now gets the type of function pointed to. */
2279 /* Check that the function is called through a compatible prototype.
2280 If it is not, replace the call by a trap, wrapped up in a compound
2281 expression if necessary. This has the nice side-effect to prevent
2282 the tree-inliner from generating invalid assignment trees which may
2283 blow up in the RTL expander later. */
2289 {
2292 NULL_TREE);
2294 /* This situation leads to run-time undefined behavior. We can't,
2295 therefore, simply error unless we can prove that all possible
2296 executions of the program must execute the code. */
2299 /* We can, however, treat "undefined" any way we please.
2300 Call abort to encourage the user to fix the program. */
2305 else
2306 {
2307 tree rhs;
2312 else
2316 }
2317 }
2319 /* Convert the parameters to the types declared in the
2320 function prototype, or apply default promotions. */
2329 /* Check that the arguments to the function are valid. */
2335 {
2342 }
2343 else
2350 }
2351 \f
2352 /* Convert the argument expressions in the list VALUES
2353 to the types in the list TYPELIST. The resulting arguments are
2354 stored in the array ARGARRAY which has size NARGS.
2356 If TYPELIST is exhausted, or when an element has NULL as its type,
2357 perform the default conversions.
2359 PARMLIST is the chain of parm decls for the function being called.
2360 It may be 0, if that info is not available.
2361 It is used only for generating error messages.
2363 FUNCTION is a tree for the called function. It is used only for
2364 error messages, where it is formatted with %qE.
2366 This is also where warnings about wrong number of args are generated.
2368 VALUES is a chain of TREE_LIST nodes with the elements of the list
2369 in the TREE_VALUE slots of those nodes.
2371 Returns the actual number of arguments processed (which may be less
2372 than NARGS in some error situations), or -1 on failure. */
2374 static int
2377 {
2380 tree selector;
2382 /* Change pointer to function to the function itself for
2383 diagnostics. */
2388 /* Handle an ObjC selector specially for diagnostics. */
2391 /* Scan the given expressions and types, producing individual
2392 converted arguments and storing them in ARGARRAY. */
2395 valtail;
2397 {
2405 {
2408 }
2411 {
2414 }
2421 {
2422 /* Formal parm type is specified by a function prototype. */
2423 tree parmval;
2426 {
2429 }
2430 else
2431 {
2432 /* Optionally warn about conversions that
2433 differ from the default conversions. */
2435 {
2468 /* ??? At some point, messages should be written about
2469 conversions between complex types, but that's too messy
2470 to do now. */
2473 {
2474 /* Warn if any argument is passed as `float',
2475 since without a prototype it would be `double'. */
2482 /* Warn if mismatch between argument and prototype
2483 for decimal float types. Warn of conversions with
2484 binary float types and of precision narrowing due to
2485 prototype. */
2493 && (formal_prec
2497 != dfloat64_type_node
2507 }
2508 /* Detect integer changing in width or signedness.
2509 These warnings are only activated with
2510 -Wtraditional-conversion, not with -Wtraditional. */
2513 {
2520 /* No warning if function asks for enum
2521 and the actual arg is that enum type. */
2522 ;
2528 ;
2529 /* Don't complain if the formal parameter type
2530 is an enum, because we can't tell now whether
2531 the value was an enum--even the same enum. */
2533 ;
2536 /* Change in signedness doesn't matter
2537 if a constant value is unaffected. */
2538 ;
2539 /* If the value is extended from a narrower
2540 unsigned type, it doesn't matter whether we
2541 pass it as signed or unsigned; the value
2542 certainly is the same either way. */
2545 ;
2550 else
2553 }
2554 }
2564 }
2566 }
2571 /* Convert `float' to `double'. */
2575 {
2578 }
2579 else
2580 /* Convert `short' and `char' to full-size `int'. */
2585 }
2590 {
2593 }
2596 }
2597 \f
2598 /* This is the entry point used by the parser to build unary operators
2599 in the input. CODE, a tree_code, specifies the unary operator, and
2600 ARG is the operand. For unary plus, the C parser currently uses
2601 CONVERT_EXPR for code. */
2603 struct c_expr
2605 {
2615 }
2617 /* This is the entry point used by the parser to build binary operators
2618 in the input. CODE, a tree_code, specifies the binary operator, and
2619 ARG1 and ARG2 are the operands. In addition to constructing the
2620 expression, we check for operands that were written with other binary
2621 operators in a way that is likely to confuse the user. */
2623 struct c_expr
2626 {
2638 /* Check for cases such as x+y<<z which users are likely
2639 to misinterpret. */
2646 /* Warn about comparisons against string literals, with the exception
2647 of testing for equality or inequality of a string literal with NULL. */
2649 {
2653 }
2664 }
2665 \f
2666 /* Return a tree for the difference of pointers OP0 and OP1.
2667 The resulting tree has type int. */
2669 static tree
2671 {
2679 {
2684 }
2686 /* If the conversion to ptrdiff_type does anything like widening or
2687 converting a partial to an integral mode, we get a convert_expression
2688 that is in the way to do any simplifications.
2689 (fold-const.c doesn't know that the extra bits won't be needed.
2690 split_tree uses STRIP_SIGN_NOPS, which leaves conversions to a
2691 different mode in place.)
2692 So first try to find a common term here 'by hand'; we want to cover
2693 at least the cases that occur in legal static initializers. */
2698 else
2704 else
2708 {
2711 }
2712 else
2716 {
2719 }
2720 else
2724 {
2727 }
2730 /* First do the subtraction as integers;
2731 then drop through to build the divide operator.
2732 Do not do default conversions on the minus operator
2733 in case restype is a short type. */
2737 /* This generates an error if op1 is pointer to incomplete type. */
2741 /* This generates an error if op0 is pointer to incomplete type. */
2744 /* Divide by the size, in easiest possible way. */
2746 }
2747 \f
2748 /* Construct and perhaps optimize a tree representation
2749 for a unary operation. CODE, a tree_code, specifies the operation
2750 and XARG is the operand.
2751 For any CODE other than ADDR_EXPR, FLAG nonzero suppresses
2752 the default promotions (such as from short to int).
2753 For ADDR_EXPR, the default promotions are not applied; FLAG nonzero
2754 allows non-lvalues; this is only used to handle conversion of non-lvalue
2755 arrays to pointers in C99. */
2757 tree
2759 {
2760 /* No default_conversion here. It causes trouble for ADDR_EXPR. */
2764 tree val;
2775 {
2778 }
2781 {
2783 /* This is used for unary plus, because a CONVERT_EXPR
2784 is enough to prevent anybody from looking inside for
2785 associativity, but won't generate any code. */
2789 {
2792 }
2802 {
2805 }
2812 {
2815 }
2817 {
2823 }
2824 else
2825 {
2828 }
2833 {
2836 }
2842 /* Conjugating a real value is a no-op, but allow it anyway. */
2845 {
2848 }
2857 {
2860 }
2869 else
2877 else
2885 /* Increment or decrement the real part of the value,
2886 and don't change the imaginary part. */
2888 {
2900 }
2902 /* Report invalid types. */
2906 {
2909 else
2913 }
2915 {
2916 tree inc;
2922 /* Compute the increment. */
2925 {
2926 /* If pointer target is an undefined struct,
2927 we just cannot know how to do the arithmetic. */
2929 {
2932 else
2934 }
2938 {
2941 else
2943 }
2946 }
2947 else
2952 /* Complain about anything else that is not a true lvalue. */
2955 ? lv_increment
2959 /* Report a read-only lvalue. */
2961 {
2967 }
2971 else
2978 }
2981 /* Note that this operation never does default_conversion. */
2983 /* Let &* cancel out to simplify resulting code. */
2985 {
2986 /* Don't let this be an lvalue. */
2990 }
2992 /* For &x[y], return x+y */
2994 {
3003 }
3005 /* Anything not already handled and not a true memory reference
3006 or a non-lvalue array is an error. */
3011 /* Ordinary case; arg is a COMPONENT_REF or a decl. */
3014 /* If the lvalue is const or volatile, merge that into the type
3015 to which the address will point. Note that you can't get a
3016 restricted pointer by taking the address of something, so we
3017 only have to deal with `const' and `volatile' here. */
3032 /* ??? Cope with user tricks that amount to offsetof. Delete this
3033 when we have proper support for integer constant expressions. */
3037 {
3042 }
3050 }
3056 }
3058 /* Return nonzero if REF is an lvalue valid for this language.
3059 Lvalues can be assigned, unless their type has TYPE_READONLY.
3060 Lvalues can have their address taken, unless they have C_DECL_REGISTER. */
3062 static int
3064 {
3068 {
3092 }
3093 }
3094 \f
3095 /* Give an error for storing in something that is 'const'. */
3097 static void
3099 {
3102 /* Using this macro rather than (for example) arrays of messages
3103 ensures that all the format strings are checked at compile
3104 time. */
3105 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A) \
3106 : (use == lv_increment ? (I) \
3107 : (use == lv_decrement ? (D) : (AS))))
3109 {
3112 else
3118 }
3124 arg);
3125 else
3130 }
3133 /* Return nonzero if REF is an lvalue valid for this language;
3134 otherwise, print an error message and return zero. USE says
3135 how the lvalue is being used and so selects the error message. */
3137 static int
3139 {
3146 }
3147 \f
3148 /* Mark EXP saying that we need to be able to take the
3149 address of it; it should not be allocated in a register.
3150 Returns true if successful. */
3152 bool
3154 {
3159 {
3162 {
3163 error
3166 }
3168 /* ... fall through ... */
3188 {
3190 {
3191 error
3194 }
3196 }
3198 {
3201 else
3204 }
3206 /* drops in */
3209 /* drops out */
3212 }
3213 }
3214 \f
3215 /* Build and return a conditional expression IFEXP ? OP1 : OP2. */
3217 tree
3219 {
3220 tree type1;
3221 tree type2;
3227 /* Promote both alternatives. */
3244 /* C90 does not permit non-lvalue arrays in conditional expressions.
3245 In C99 they will be pointers by now. */
3247 {
3250 }
3252 /* Quickly detect the usual case where op1 and op2 have the same type
3253 after promotion. */
3255 {
3258 else
3260 }
3265 {
3268 /* If -Wsign-compare, warn here if type1 and type2 have
3269 different signedness. We'll promote the signed to unsigned
3270 and later code won't know it used to be different.
3271 Do this check on the original types, so that explicit casts
3272 will be considered, but default promotions won't. */
3274 {
3279 {
3282 /* Do not warn if the result type is signed, since the
3283 signed type will only be chosen if it can represent
3284 all the values of the unsigned type. */
3287 /* Do not warn if the signed quantity is an unsuffixed
3288 integer literal (or some static constant expression
3289 involving such literals) and it is non-negative. */
3292 || (unsigned_op1
3295 else
3297 }
3298 }
3299 }
3301 {
3305 }
3307 {
3315 {
3321 }
3323 {
3329 }
3330 else
3331 {
3334 }
3335 }
3337 {
3340 else
3341 {
3343 }
3345 }
3347 {
3350 else
3351 {
3353 }
3355 }
3358 {
3361 else
3362 {
3365 }
3366 }
3368 /* Merge const and volatile flags of the incoming types. */
3369 result_type
3380 }
3381 \f
3382 /* Return a compound expression that performs two expressions and
3383 returns the value of the second of them. */
3385 tree
3387 {
3389 {
3390 /* The left-hand operand of a comma expression is like an expression
3391 statement: with -Wextra or -Wunused, we should warn if it doesn't have
3392 any side-effects, unless it was explicitly cast to (void). */
3394 {
3404 else
3407 }
3408 }
3410 /* With -Wunused, we should also warn if the left-hand operand does have
3411 side-effects, but computes a value which is not used. For example, in
3412 `foo() + bar(), baz()' the result of the `+' operator is not used,
3413 so we should issue a warning. */
3421 }
3423 /* Build an expression representing a cast to type TYPE of expression EXPR. */
3425 tree
3427 {
3433 /* The ObjC front-end uses TYPE_MAIN_VARIANT to tie together types differing
3434 only in <protocol> qualifications. But when constructing cast expressions,
3435 the protocols do matter and must be kept around. */
3442 {
3445 }
3448 {
3451 }
3454 {
3456 {
3460 }
3461 }
3463 {
3464 tree field;
3472 {
3473 tree t;
3483 }
3486 }
3487 else
3488 {
3496 /* Optionally warn about potentially worrisome casts. */
3501 {
3507 /* Check that the qualifiers on IN_TYPE are a superset of
3508 the qualifiers of IN_OTYPE. The outermost level of
3509 POINTER_TYPE nodes is uninteresting and we stop as soon
3510 as we hit a non-POINTER_TYPE node on either type. */
3511 do
3512 {
3516 /* GNU C allows cv-qualified function types. 'const'
3517 means the function is very pure, 'volatile' means it
3518 can't return. We need to warn when such qualifiers
3519 are added, not when they're taken away. */
3523 else
3525 }
3533 /* There are qualifiers present in IN_OTYPE that are not
3534 present in IN_TYPE. */
3536 }
3538 /* Warn about possible alignment problems. */
3544 /* Don't warn about opaque types, where the actual alignment
3545 restriction is unknown. */
3556 /* Unlike conversion of integers to pointers, where the
3557 warning is disabled for converting constants because
3558 of cases such as SIG_*, warn about converting constant
3559 pointers to integers. In some cases it may cause unwanted
3560 sign extension, and a warning is appropriate. */
3572 /* Don't warn about converting any constant. */
3579 /* If pedantic, warn for conversions between function and object
3580 pointer types, except for converting a null pointer constant
3581 to function pointer type. */
3600 /* Ignore any integer overflow caused by the cast. */
3602 {
3604 {
3606 {
3607 /* Avoid clobbering a shared constant. */
3610 }
3611 }
3613 /* Reset VALUE's overflow flags, ensuring constant sharing. */
3617 }
3618 }
3620 /* Don't let a cast be an lvalue. */
3625 }
3627 /* Interpret a cast of expression EXPR to type TYPE. */
3628 tree
3630 {
3631 tree type;
3634 /* This avoids warnings about unprototyped casts on
3635 integers. E.g. "#define SIG_DFL (void(*)())0". */
3642 }
3643 \f
3644 /* Build an assignment expression of lvalue LHS from value RHS.
3645 MODIFYCODE is the code for a binary operator that we use
3646 to combine the old value of LHS with RHS to get the new value.
3647 Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment. */
3649 tree
3651 {
3652 tree result;
3653 tree newrhs;
3657 /* Types that aren't fully specified cannot be used in assignments. */
3660 /* Avoid duplicate error messages from operands that had errors. */
3671 /* If a binary op has been requested, combine the old LHS value with the RHS
3672 producing the value we should actually store into the LHS. */
3675 {
3678 }
3680 /* Give an error for storing in something that is 'const'. */
3686 {
3689 }
3691 /* If storing into a structure or union member,
3692 it has probably been given type `int'.
3693 Compute the type that would go with
3694 the actual amount of storage the member occupies. */
3703 /* If storing in a field that is in actuality a short or narrower than one,
3704 we must store in the field in its actual type. */
3707 {
3710 }
3712 /* Convert new value to destination type. */
3719 /* Emit ObjC write barrier, if necessary. */
3721 {
3725 }
3727 /* Scan operands. */
3732 /* If we got the LHS in a different type for storing in,
3733 convert the result back to the nominal type of LHS
3734 so that the value we return always has the same type
3735 as the LHS argument. */
3741 }
3742 \f
3743 /* Convert value RHS to type TYPE as preparation for an assignment
3744 to an lvalue of type TYPE.
3745 The real work of conversion is done by `convert'.
3746 The purpose of this function is to generate error messages
3747 for assignments that are not allowed in C.
3748 ERRTYPE says whether it is argument passing, assignment,
3749 initialization or return.
3751 FUNCTION is a tree for the function being called.
3752 PARMNUM is the number of the argument, for printing in error messages. */
3754 static tree
3757 {
3759 tree rhstype;
3765 {
3766 tree selector;
3767 /* Change pointer to function to the function itself for
3768 diagnostics. */
3773 /* Handle an ObjC selector specially for diagnostics. */
3777 {
3780 }
3781 }
3783 /* This macro is used to emit diagnostics to ensure that all format
3784 strings are complete sentences, visible to gettext and checked at
3785 compile time. */
3786 #define WARN_FOR_ASSIGNMENT(AR, AS, IN, RE) \
3787 do { \
3788 switch (errtype) \
3789 { \
3790 case ic_argpass: \
3791 pedwarn (AR, parmnum, rname); \
3792 break; \
3793 case ic_argpass_nonproto: \
3794 warning (0, AR, parmnum, rname); \
3795 break; \
3796 case ic_assign: \
3797 pedwarn (AS); \
3798 break; \
3799 case ic_init: \
3800 pedwarn (IN); \
3801 break; \
3802 case ic_return: \
3803 pedwarn (RE); \
3804 break; \
3805 default: \
3806 gcc_unreachable (); \
3807 } \
3808 } while (0)
3823 {
3827 {
3843 }
3846 }
3852 {
3853 /* Except for passing an argument to an unprototyped function,
3854 this is a constraint violation. When passing an argument to
3855 an unprototyped function, it is compile-time undefined;
3856 making it a constraint in that case was rejected in
3857 DR#252. */
3860 }
3861 /* A type converts to a reference to it.
3862 This code doesn't fully support references, it's just for the
3863 special case of va_start and va_copy. */
3866 {
3868 {
3871 }
3876 /* We already know that these two types are compatible, but they
3877 may not be exactly identical. In fact, `TREE_TYPE (type)' is
3878 likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
3879 likely to be va_list, a typedef to __builtin_va_list, which
3880 is different enough that it will cause problems later. */
3886 }
3887 /* Some types can interconvert without explicit casts. */
3891 /* Arithmetic types all interconvert, and enum is treated like int. */
3900 /* Aggregates in different TUs might need conversion. */
3906 /* Conversion to a transparent union from its member types.
3907 This applies only to function arguments. */
3910 {
3914 {
3925 {
3929 /* Any non-function converts to a [const][volatile] void *
3930 and vice versa; otherwise, targets must be the same.
3931 Meanwhile, the lhs target must have all the qualifiers of
3932 the rhs. */
3935 {
3936 /* If this type won't generate any warnings, use it. */
3946 /* Keep looking for a better type, but remember this one. */
3949 }
3950 }
3952 /* Can convert integer zero to any pointer type. */
3954 {
3957 }
3958 }
3961 {
3963 {
3964 /* We have only a marginally acceptable member type;
3965 it needs a warning. */
3969 /* Const and volatile mean something different for function
3970 types, so the usual warnings are not appropriate. */
3973 {
3974 /* Because const and volatile on functions are
3975 restrictions that say the function will not do
3976 certain things, it is okay to use a const or volatile
3977 function where an ordinary one is wanted, but not
3978 vice-versa. */
3981 "makes qualified function "
3984 "function pointer from "
3987 "function pointer from "
3991 }
4003 }
4009 }
4010 }
4012 /* Conversions among pointers */
4015 {
4027 /* Opaque pointers are treated like void pointers. */
4033 /* C++ does not allow the implicit conversion void* -> T*. However,
4034 for the purpose of reducing the number of false positives, we
4035 tolerate the special case of
4037 int *p = NULL;
4039 where NULL is typically defined in C to be '(void *) 0'. */
4044 /* Check if the right-hand side has a format attribute but the
4045 left-hand side doesn't. */
4048 {
4050 {
4054 "argument %d of %qE might be "
4060 "assignment left-hand side might be "
4065 "initialization left-hand side might be "
4070 "return type might be "
4075 }
4076 }
4078 /* Any non-function converts to a [const][volatile] void *
4079 and vice versa; otherwise, targets must be the same.
4080 Meanwhile, the lhs target must have all the qualifiers of the rhs. */
4083 || is_opaque_pointer
4086 {
4089 ||
4094 "%qE between function pointer "
4102 /* Const and volatile mean something different for function types,
4103 so the usual warnings are not appropriate. */
4106 {
4108 {
4109 /* Types differing only by the presence of the 'volatile'
4110 qualifier are acceptable if the 'volatile' has been added
4111 in by the Objective-C EH machinery. */
4121 }
4122 /* If this is not a case of ignoring a mismatch in signedness,
4123 no warning. */
4126 ;
4127 /* If there is a mismatch, do warn. */
4137 }
4140 {
4141 /* Because const and volatile on functions are restrictions
4142 that say the function will not do certain things,
4143 it is okay to use a const or volatile function
4144 where an ordinary one is wanted, but not vice-versa. */
4147 "qualified function pointer "
4155 }
4156 }
4157 else
4158 /* Avoid warning about the volatile ObjC EH puts on decls. */
4168 }
4170 {
4171 /* ??? This should not be an error when inlining calls to
4172 unprototyped functions. */
4175 }
4177 {
4178 /* An explicit constant 0 can convert to a pointer,
4179 or one that results from arithmetic, even including
4180 a cast to integer type. */
4192 }
4194 {
4204 }
4209 {
4212 /* ??? This should not be an error when inlining calls to
4213 unprototyped functions. */
4227 }
4230 }
4232 /* Convert VALUE for assignment into inlined parameter PARM. ARGNUM
4233 is used for error and warning reporting and indicates which argument
4234 is being processed. */
4236 tree
4238 {
4241 /* If FN was prototyped at the call site, the value has been converted
4242 already in convert_arguments.
4243 However, we might see a prototype now that was not in place when
4244 the function call was seen, so check that the VALUE actually matches
4245 PARM before taking an early exit. */
4261 }
4262 \f
4263 /* If VALUE is a compound expr all of whose expressions are constant, then
4264 return its value. Otherwise, return error_mark_node.
4266 This is for handling COMPOUND_EXPRs as initializer elements
4267 which is allowed with a warning when -pedantic is specified. */
4269 static tree
4271 {
4273 {
4278 endtype);
4279 }
4282 else
4284 }
4285 \f
4286 /* Perform appropriate conversions on the initial value of a variable,
4287 store it in the declaration DECL,
4288 and print any error messages that are appropriate.
4289 If the init is invalid, store an ERROR_MARK. */
4291 void
4293 {
4296 /* If variable's type was invalidly declared, just ignore it. */
4302 /* Digest the specified initializer into an expression. */
4306 /* Store the expression if valid; else report error. */
4315 /* ANSI wants warnings about out-of-range constant initializers. */
4320 /* Check if we need to set array size from compound literal size. */
4324 {
4331 {
4335 {
4336 /* For int foo[] = (int [3]){1}; we need to set array size
4337 now since later on array initializer will be just the
4338 brace enclosed list of the compound literal. */
4344 }
4345 }
4346 }
4347 }
4348 \f
4349 /* Methods for storing and printing names for error messages. */
4351 /* Implement a spelling stack that allows components of a name to be pushed
4352 and popped. Each element on the stack is this structure. */
4354 struct spelling
4355 {
4357 union
4358 {
4362 };
4364 #define SPELLING_STRING 1
4365 #define SPELLING_MEMBER 2
4366 #define SPELLING_BOUNDS 3
4372 /* Macros to save and restore the spelling stack around push_... functions.
4373 Alternative to SAVE_SPELLING_STACK. */
4375 #define SPELLING_DEPTH() (spelling - spelling_base)
4376 #define RESTORE_SPELLING_DEPTH(DEPTH) (spelling = spelling_base + (DEPTH))
4378 /* Push an element on the spelling stack with type KIND and assign VALUE
4379 to MEMBER. */
4381 #define PUSH_SPELLING(KIND, VALUE, MEMBER) \
4382 { \
4383 int depth = SPELLING_DEPTH (); \
4384 \
4385 if (depth >= spelling_size) \
4386 { \
4387 spelling_size += 10; \
4388 spelling_base = XRESIZEVEC (struct spelling, spelling_base, \
4389 spelling_size); \
4390 RESTORE_SPELLING_DEPTH (depth); \
4391 } \
4392 \
4393 spelling->kind = (KIND); \
4394 spelling->MEMBER = (VALUE); \
4395 spelling++; \
4396 }
4398 /* Push STRING on the stack. Printed literally. */
4400 static void
4402 {
4404 }
4406 /* Push a member name on the stack. Printed as '.' STRING. */
4408 static void
4410 {
4414 }
4416 /* Push an array bounds on the stack. Printed as [BOUNDS]. */
4418 static void
4420 {
4422 }
4424 /* Compute the maximum size in bytes of the printed spelling. */
4426 static int
4428 {
4433 {
4436 else
4438 }
4441 }
4443 /* Print the spelling to BUFFER and return it. */
4447 {
4453 {
4456 }
4457 else
4458 {
4463 ;
4464 }
4467 }
4469 /* Issue an error message for a bad initializer component.
4470 MSGID identifies the message.
4471 The component name is taken from the spelling stack. */
4473 void
4475 {
4482 }
4484 /* Issue a pedantic warning for a bad initializer component.
4485 MSGID identifies the message.
4486 The component name is taken from the spelling stack. */
4488 void
4490 {
4497 }
4499 /* Issue a warning for a bad initializer component.
4500 MSGID identifies the message.
4501 The component name is taken from the spelling stack. */
4503 static void
4505 {
4512 }
4513 \f
4514 /* If TYPE is an array type and EXPR is a parenthesized string
4515 constant, warn if pedantic that EXPR is being used to initialize an
4516 object of type TYPE. */
4518 void
4520 {
4526 }
4528 /* Digest the parser output INIT as an initializer for type TYPE.
4529 Return a C expression of type TYPE to represent the initial value.
4531 If INIT is a string constant, STRICT_STRING is true if it is
4532 unparenthesized or we should not warn here for it being parenthesized.
4533 For other types of INIT, STRICT_STRING is not used.
4535 REQUIRE_CONSTANT requests an error if non-constant initializers or
4536 elements are seen. */
4538 static tree
4540 {
4545 || !init
4554 /* Initialization of an array of chars from a string constant
4555 optionally enclosed in braces. */
4559 {
4561 /* Note that an array could be both an array of character type
4562 and an array of wchar_t if wchar_t is signed char or unsigned
4563 char. */
4569 {
4576 char_string
4585 {
4588 }
4590 {
4593 }
4599 /* Subtract 1 (or sizeof (wchar_t))
4600 because it's ok to ignore the terminating null char
4601 that is counted in the length of the constant. */
4612 }
4614 {
4618 }
4619 }
4621 /* Build a VECTOR_CST from a *constant* vector constructor. If the
4622 vector constructor is not constant (e.g. {1,2,3,foo()}) then punt
4623 below and handle as a constructor. */
4628 {
4635 {
4637 tree value;
4640 /* Iterate through elements and check if all constructor
4641 elements are *_CSTs. */
4644 {
4647 }
4652 }
4653 }
4655 /* Any type can be initialized
4656 from an expression of the same type, optionally with braces. */
4669 {
4671 {
4673 {
4677 else
4678 {
4681 }
4682 }
4683 }
4686 /* Although the types are compatible, we may require a
4687 conversion. */
4693 {
4694 /* As an extension, allow initializing objects with static storage
4695 duration with compound literals (which are then treated just as
4696 the brace enclosed list they contain). Also allow this for
4697 vectors, as we can only assign them with compound literals. */
4700 }
4704 {
4707 }
4712 /* Compound expressions can only occur here if -pedantic or
4713 -pedantic-errors is specified. In the later case, we always want
4714 an error. In the former case, we simply want a warning. */
4717 {
4718 inside_init
4723 else
4727 }
4731 {
4734 }
4736 /* Added to enable additional -Wmissing-format-attribute warnings. */
4741 }
4743 /* Handle scalar types, including conversions. */
4748 {
4753 inside_init
4757 /* Check to see if we have already given an error message. */
4759 ;
4761 {
4764 }
4768 {
4771 }
4774 }
4776 /* Come here only for records and arrays. */
4779 {
4782 }
4786 }
4787 \f
4788 /* Handle initializers that use braces. */
4790 /* Type of object we are accumulating a constructor for.
4791 This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE. */
4794 /* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
4795 left to fill. */
4798 /* For an ARRAY_TYPE, this is the specified index
4799 at which to store the next element we get. */
4802 /* For an ARRAY_TYPE, this is the maximum index. */
4805 /* For a RECORD_TYPE, this is the first field not yet written out. */
4808 /* For an ARRAY_TYPE, this is the index of the first element
4809 not yet written out. */
4812 /* In a RECORD_TYPE, the byte index of the next consecutive field.
4813 This is so we can generate gaps between fields, when appropriate. */
4816 /* If we are saving up the elements rather than allocating them,
4817 this is the list of elements so far (in reverse order,
4818 most recent first). */
4821 /* 1 if constructor should be incrementally stored into a constructor chain,
4822 0 if all the elements should be kept in AVL tree. */
4825 /* 1 if so far this constructor's elements are all compile-time constants. */
4828 /* 1 if so far this constructor's elements are all valid address constants. */
4831 /* 1 if this constructor is erroneous so far. */
4834 /* Structure for managing pending initializer elements, organized as an
4835 AVL tree. */
4837 struct init_node
4838 {
4842 tree purpose;
4843 tree value;
4844 };
4846 /* Tree of pending elements at this constructor level.
4847 These are elements encountered out of order
4848 which belong at places we haven't reached yet in actually
4849 writing the output.
4850 Will never hold tree nodes across GC runs. */
4853 /* The SPELLING_DEPTH of this constructor. */
4856 /* DECL node for which an initializer is being read.
4857 0 means we are reading a constructor expression
4858 such as (struct foo) {...}. */
4861 /* Nonzero if this is an initializer for a top-level decl. */
4864 /* Nonzero if there were any member designators in this initializer. */
4867 /* Nesting depth of designator list. */
4870 /* Nonzero if there were diagnosed errors in this designator list. */
4873 \f
4874 /* This stack has a level for each implicit or explicit level of
4875 structuring in the initializer, including the outermost one. It
4876 saves the values of most of the variables above. */
4880 struct constructor_stack
4881 {
4883 tree type;
4884 tree fields;
4885 tree index;
4886 tree max_index;
4887 tree unfilled_index;
4888 tree unfilled_fields;
4889 tree bit_index;
4894 /* If value nonzero, this value should replace the entire
4895 constructor at this level. */
4905 };
4909 /* This stack represents designators from some range designator up to
4910 the last designator in the list. */
4912 struct constructor_range_stack
4913 {
4916 tree range_start;
4917 tree index;
4918 tree range_end;
4919 tree fields;
4920 };
4924 /* This stack records separate initializers that are nested.
4925 Nested initializers can't happen in ANSI C, but GNU C allows them
4926 in cases like { ... (struct foo) { ... } ... }. */
4928 struct initializer_stack
4929 {
4931 tree decl;
4941 };
4944 \f
4945 /* Prepare to parse and output the initializer for variable DECL. */
4947 void
4949 {
4971 {
4973 require_constant_elements
4975 /* For a scalar, you can always use any value to initialize,
4976 even within braces. */
4982 }
4983 else
4984 {
4988 }
5001 }
5003 void
5005 {
5008 /* Free the whole constructor stack of this initializer. */
5010 {
5014 }
5018 /* Pop back to the data of the outer initializer (if any). */
5033 }
5034 \f
5035 /* Call here when we see the initializer is surrounded by braces.
5036 This is instead of a call to push_init_level;
5037 it is matched by a call to pop_init_level.
5039 TYPE is the type to initialize, for a constructor expression.
5040 For an initializer for a decl, TYPE is zero. */
5042 void
5044 {
5089 {
5091 /* Skip any nameless bit fields at the beginning. */
5098 }
5100 {
5102 {
5103 constructor_max_index
5106 /* Detect non-empty initializations of zero-length arrays. */
5111 /* constructor_max_index needs to be an INTEGER_CST. Attempts
5112 to initialize VLAs will cause a proper error; avoid tree
5113 checking errors as well by setting a safe value. */
5118 constructor_index
5121 }
5122 else
5123 {
5126 }
5129 }
5131 {
5132 /* Vectors are like simple fixed-size arrays. */
5133 constructor_max_index =
5137 }
5138 else
5139 {
5140 /* Handle the case of int x = {5}; */
5143 }
5144 }
5145 \f
5146 /* Push down into a subobject, for initialization.
5147 If this is for an explicit set of braces, IMPLICIT is 0.
5148 If it is because the next element belongs at a lower level,
5149 IMPLICIT is 1 (or 2 if the push is because of designator list). */
5151 void
5153 {
5157 /* If we've exhausted any levels that didn't have braces,
5158 pop them now. If implicit == 1, this will have been done in
5159 process_init_element; do not repeat it here because in the case
5160 of excess initializers for an empty aggregate this leads to an
5161 infinite cycle of popping a level and immediately recreating
5162 it. */
5164 {
5166 {
5172 && constructor_max_index
5174 constructor_index))
5176 else
5178 }
5179 }
5181 /* Unless this is an explicit brace, we need to preserve previous
5182 content if any. */
5184 {
5191 }
5225 {
5230 }
5232 /* Don't die if an entire brace-pair level is superfluous
5233 in the containing level. */
5235 ;
5238 {
5239 /* Don't die if there are extra init elts at the end. */
5242 else
5243 {
5246 constructor_depth++;
5247 }
5248 }
5250 {
5253 constructor_depth++;
5254 }
5257 {
5262 }
5265 {
5273 }
5276 {
5279 }
5283 {
5285 /* Skip any nameless bit fields at the beginning. */
5292 }
5294 {
5295 /* Vectors are like simple fixed-size arrays. */
5296 constructor_max_index =
5300 }
5302 {
5304 {
5305 constructor_max_index
5308 /* Detect non-empty initializations of zero-length arrays. */
5313 /* constructor_max_index needs to be an INTEGER_CST. Attempts
5314 to initialize VLAs will cause a proper error; avoid tree
5315 checking errors as well by setting a safe value. */
5320 constructor_index
5323 }
5324 else
5329 {
5330 /* We need to split the char/wchar array into individual
5331 characters, so that we don't have to special case it
5332 everywhere. */
5334 }
5335 }
5336 else
5337 {
5342 }
5343 }
5345 /* At the end of an implicit or explicit brace level,
5346 finish up that level of constructor. If a single expression
5347 with redundant braces initialized that level, return the
5348 c_expr structure for that expression. Otherwise, the original_code
5349 element is set to ERROR_MARK.
5350 If we were outputting the elements as they are read, return 0 as the value
5351 from inner levels (process_init_element ignores that),
5352 but return error_mark_node as the value from the outermost level
5353 (that's what we want to put in DECL_INITIAL).
5354 Otherwise, return a CONSTRUCTOR expression as the value. */
5356 struct c_expr
5358 {
5365 {
5366 /* When we come to an explicit close brace,
5367 pop any inner levels that didn't have explicit braces. */
5372 }
5374 /* Now output all pending elements. */
5380 /* Error for initializing a flexible array member, or a zero-length
5381 array member in an inappropriate context. */
5386 {
5387 /* Silently discard empty initializations. The parser will
5388 already have pedwarned for empty brackets. */
5391 else
5392 {
5400 /* We have already issued an error message for the existence
5401 of a flexible array member not at the end of the structure.
5402 Discard the initializer so that we do not die later. */
5405 }
5406 }
5408 /* Warn when some struct elements are implicitly initialized to zero. */
5410 && constructor_type
5413 {
5414 /* Do not warn for flexible array members or zero-length arrays. */
5420 /* Do not warn if this level of the initializer uses member
5421 designators; it is likely to be deliberate. */
5423 {
5427 }
5428 }
5430 /* Pad out the end of the structure. */
5432 /* If this closes a superfluous brace pair,
5433 just pass out the element between them. */
5436 ;
5441 {
5442 /* A nonincremental scalar initializer--just return
5443 the element, after verifying there is just one. */
5445 {
5449 }
5451 {
5454 }
5455 else
5457 }
5458 else
5459 {
5462 else
5463 {
5465 constructor_elements);
5470 }
5471 }
5498 }
5500 /* Common handling for both array range and field name designators.
5501 ARRAY argument is nonzero for array ranges. Returns zero for success. */
5503 static int
5505 {
5506 tree subtype;
5509 /* Don't die if an entire brace-pair level is superfluous
5510 in the containing level. */
5514 /* If there were errors in this designator list already, bail out
5515 silently. */
5520 {
5523 /* Designator list starts at the level of closest explicit
5524 braces. */
5529 }
5532 {
5544 }
5548 {
5551 }
5553 {
5556 }
5561 }
5563 /* If there are range designators in designator list, push a new designator
5564 to constructor_range_stack. RANGE_END is end of such stack range or
5565 NULL_TREE if there is no range designator at this level. */
5567 static void
5569 {
5583 }
5585 /* Within an array initializer, specify the next index to be initialized.
5586 FIRST is that index. If LAST is nonzero, then initialize a range
5587 of indices, running from FIRST through LAST. */
5589 void
5591 {
5599 {
5602 }
5615 else
5616 {
5620 {
5624 {
5627 }
5628 else
5629 {
5633 {
5636 }
5637 }
5638 }
5640 designator_depth++;
5644 }
5645 }
5647 /* Within a struct initializer, specify the next field to be initialized. */
5649 void
5651 {
5652 tree tail;
5661 {
5664 }
5668 {
5671 }
5675 else
5676 {
5678 designator_depth++;
5682 }
5683 }
5684 \f
5685 /* Add a new initializer to the tree of pending initializers. PURPOSE
5686 identifies the initializer, either array index or field in a structure.
5687 VALUE is the value of that index or field. */
5689 static void
5691 {
5698 {
5700 {
5706 else
5707 {
5714 }
5715 }
5716 }
5717 else
5718 {
5719 tree bitpos;
5723 {
5729 else
5730 {
5737 }
5738 }
5739 }
5752 {
5756 {
5760 {
5762 {
5763 /* L rotation. */
5776 {
5779 else
5781 }
5782 else
5784 }
5785 else
5786 {
5787 /* LR rotation. */
5809 {
5812 else
5814 }
5815 else
5817 }
5819 }
5820 else
5821 {
5822 /* p->balance == +1; growth of left side balances the node. */
5825 }
5826 }
5828 {
5830 /* Growth propagation from right side. */
5833 {
5835 {
5836 /* R rotation. */
5849 {
5852 else
5854 }
5855 else
5857 }
5859 {
5860 /* RL rotation */
5882 {
5885 else
5887 }
5888 else
5890 }
5892 }
5893 else
5894 {
5895 /* p->balance == -1; growth of right side balances the node. */
5898 }
5899 }
5903 }
5904 }
5906 /* Build AVL tree from a sorted chain. */
5908 static void
5910 {
5922 {
5924 /* Skip any nameless bit fields at the beginning. */
5930 }
5932 {
5934 constructor_unfilled_index
5937 else
5939 }
5941 }
5943 /* Build AVL tree from a string constant. */
5945 static void
5947 {
5958 else
5959 {
5963 }
5972 {
5974 {
5977 }
5978 else
5979 {
5983 {
5986 else
5991 }
5992 }
5995 {
5998 {
6000 {
6003 }
6004 }
6006 {
6009 }
6014 }
6018 }
6021 }
6023 /* Return value of FIELD in pending initializer or zero if the field was
6024 not initialized yet. */
6026 static tree
6028 {
6032 {
6039 {
6044 else
6046 }
6047 }
6049 {
6053 && (!constructor_unfilled_fields
6060 {
6065 else
6067 }
6068 }
6070 {
6075 }
6077 }
6079 /* "Output" the next constructor element.
6080 At top level, really output it to assembler code now.
6081 Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
6082 TYPE is the data type that the containing data type wants here.
6083 FIELD is the field (a FIELD_DECL) or the index that this element fills.
6084 If VALUE is a string constant, STRICT_STRING is true if it is
6085 unparenthesized or we should not warn here for it being parenthesized.
6086 For other types of VALUE, STRICT_STRING is not used.
6088 PENDING if non-nil means output pending elements that belong
6089 right after this element. (PENDING is normally 1;
6090 it is 0 while outputting pending elements, to avoid recursion.) */
6092 static void
6095 {
6099 {
6102 }
6115 {
6116 /* As an extension, allow initializing objects with static storage
6117 duration with compound literals (which are then treated just as
6118 the brace enclosed list they contain). */
6121 }
6135 {
6137 {
6140 }
6143 }
6145 /* If this field is empty (and not at the end of structure),
6146 don't do anything other than checking the initializer. */
6157 {
6160 }
6162 /* If this element doesn't come next in sequence,
6163 put it on constructor_pending_elts. */
6165 && (!constructor_incremental
6167 {
6174 }
6176 && (!constructor_incremental
6178 {
6179 /* We do this for records but not for unions. In a union,
6180 no matter which field is specified, it can be initialized
6181 right away since it starts at the beginning of the union. */
6183 {
6186 else
6187 {
6195 }
6196 }
6200 }
6203 {
6210 /* We can have just one union field set. */
6212 }
6214 /* Otherwise, output this element either to
6215 constructor_elements or to the assembler file. */
6221 /* Advance the variable that indicates sequential elements output. */
6223 constructor_unfilled_index
6225 bitsize_one_node);
6227 {
6228 constructor_unfilled_fields
6231 /* Skip any nameless bit fields. */
6235 constructor_unfilled_fields =
6237 }
6241 /* Now output any pending elements which have become next. */
6244 }
6246 /* Output any pending elements which have become next.
6247 As we output elements, constructor_unfilled_{fields,index}
6248 advances, which may cause other elements to become next;
6249 if so, they too are output.
6251 If ALL is 0, we return when there are
6252 no more pending elements to output now.
6254 If ALL is 1, we output space as necessary so that
6255 we can output all the pending elements. */
6257 static void
6259 {
6261 tree next;
6263 retry:
6265 /* Look through the whole pending tree.
6266 If we find an element that should be output now,
6267 output it. Otherwise, set NEXT to the element
6268 that comes first among those still pending. */
6272 {
6274 {
6276 constructor_unfilled_index))
6282 {
6283 /* Advance to the next smaller node. */
6286 else
6287 {
6288 /* We have reached the smallest node bigger than the
6289 current unfilled index. Fill the space first. */
6292 }
6293 }
6294 else
6295 {
6296 /* Advance to the next bigger node. */
6299 else
6300 {
6301 /* We have reached the biggest node in a subtree. Find
6302 the parent of it, which is the next bigger node. */
6308 {
6311 }
6312 }
6313 }
6314 }
6317 {
6320 /* If the current record is complete we are done. */
6326 /* We can't compare fields here because there might be empty
6327 fields in between. */
6329 {
6333 }
6335 {
6336 /* Advance to the next smaller node. */
6339 else
6340 {
6341 /* We have reached the smallest node bigger than the
6342 current unfilled field. Fill the space first. */
6345 }
6346 }
6347 else
6348 {
6349 /* Advance to the next bigger node. */
6352 else
6353 {
6354 /* We have reached the biggest node in a subtree. Find
6355 the parent of it, which is the next bigger node. */
6362 {
6365 }
6366 }
6367 }
6368 }
6369 }
6371 /* Ordinarily return, but not if we want to output all
6372 and there are elements left. */
6376 /* If it's not incremental, just skip over the gap, so that after
6377 jumping to retry we will output the next successive element. */
6384 /* ELT now points to the node in the pending tree with the next
6385 initializer to output. */
6387 }
6388 \f
6389 /* Add one non-braced element to the current constructor level.
6390 This adjusts the current position within the constructor's type.
6391 This may also start or terminate implicit levels
6392 to handle a partly-braced initializer.
6394 Once this has found the correct level for the new element,
6395 it calls output_init_element. */
6397 void
6399 {
6407 /* Handle superfluous braces around string cst as in
6408 char x[] = {"foo"}; */
6410 && constructor_type
6414 {
6419 }
6422 {
6425 }
6427 /* Ignore elements of a brace group if it is entirely superfluous
6428 and has already been diagnosed. */
6432 /* If we've exhausted any levels that didn't have braces,
6433 pop them now. */
6435 {
6443 constructor_index)))
6445 else
6447 }
6449 /* In the case of [LO ... HI] = VALUE, only evaluate VALUE once. */
6451 {
6452 /* If value is a compound literal and we'll be just using its
6453 content, don't put it into a SAVE_EXPR. */
6455 || !require_constant_value
6458 }
6461 {
6463 {
6464 tree fieldtype;
6468 {
6471 }
6478 /* Error for non-static initialization of a flexible array member. */
6480 && !require_constant_value
6483 {
6486 }
6488 /* Accept a string constant to initialize a subarray. */
6494 /* Otherwise, if we have come to a subaggregate,
6495 and we don't have an element of its type, push into it. */
6501 {
6504 }
6507 {
6512 }
6513 else
6514 /* Do the bookkeeping for an element that was
6515 directly output as a constructor. */
6516 {
6517 /* For a record, keep track of end position of last field. */
6519 constructor_bit_index
6524 /* If the current field was the first one not yet written out,
6525 it isn't now, so update. */
6527 {
6529 /* Skip any nameless bit fields. */
6533 constructor_unfilled_fields =
6535 }
6536 }
6539 /* Skip any nameless bit fields at the beginning. */
6544 }
6546 {
6547 tree fieldtype;
6551 {
6554 }
6561 /* Warn that traditional C rejects initialization of unions.
6562 We skip the warning if the value is zero. This is done
6563 under the assumption that the zero initializer in user
6564 code appears conditioned on e.g. __STDC__ to avoid
6565 "missing initializer" warnings and relies on default
6566 initialization to zero in the traditional C case.
6567 We also skip the warning if the initializer is designated,
6568 again on the assumption that this must be conditional on
6569 __STDC__ anyway (and we've already complained about the
6570 member-designator already). */
6577 /* Accept a string constant to initialize a subarray. */
6583 /* Otherwise, if we have come to a subaggregate,
6584 and we don't have an element of its type, push into it. */
6590 {
6593 }
6596 {
6601 }
6602 else
6603 /* Do the bookkeeping for an element that was
6604 directly output as a constructor. */
6605 {
6608 }
6611 }
6613 {
6617 /* Accept a string constant to initialize a subarray. */
6623 /* Otherwise, if we have come to a subaggregate,
6624 and we don't have an element of its type, push into it. */
6630 {
6633 }
6638 {
6641 }
6643 /* Now output the actual element. */
6645 {
6650 }
6652 constructor_index
6656 /* If we are doing the bookkeeping for an element that was
6657 directly output as a constructor, we must update
6658 constructor_unfilled_index. */
6660 }
6662 {
6665 /* Do a basic check of initializer size. Note that vectors
6666 always have a fixed size derived from their type. */
6668 {
6671 }
6673 /* Now output the actual element. */
6678 constructor_index
6682 /* If we are doing the bookkeeping for an element that was
6683 directly output as a constructor, we must update
6684 constructor_unfilled_index. */
6686 }
6688 /* Handle the sole element allowed in a braced initializer
6689 for a scalar variable. */
6692 {
6695 }
6696 else
6697 {
6702 }
6704 /* Handle range initializers either at this level or anywhere higher
6705 in the designator stack. */
6707 {
6714 {
6717 }
6721 {
6724 }
6731 {
6735 {
6738 }
6746 }
6751 }
6754 }
6757 }
6758 \f
6759 /* Build a complete asm-statement, whose components are a CV_QUALIFIER
6760 (guaranteed to be 'volatile' or null) and ARGS (represented using
6761 an ASM_EXPR node). */
6762 tree
6764 {
6768 }
6770 /* Build an asm-expr, whose components are a STRING, some OUTPUTS,
6771 some INPUTS, and some CLOBBERS. The latter three may be NULL.
6772 SIMPLE indicates whether there was anything at all after the
6773 string in the asm expression -- asm("blah") and asm("blah" : )
6774 are subtly different. We use a ASM_EXPR node to represent this. */
6775 tree
6778 {
6779 tree tail;
6780 tree args;
6793 /* Remove output conversions that change the type but not the mode. */
6795 {
6798 /* ??? Really, this should not be here. Users should be using a
6799 proper lvalue, dammit. But there's a long history of using casts
6800 in the output operands. In cases like longlong.h, this becomes a
6801 primitive form of typechecking -- if the cast can be removed, then
6802 the output operand had a type of the proper width; otherwise we'll
6803 get an error. Gross, but ... */
6822 {
6823 /* If the operand is going to end up in memory,
6824 mark it addressable. */
6827 }
6828 else
6832 }
6835 {
6836 tree input;
6843 {
6844 /* If the operand is going to end up in memory,
6845 mark it addressable. */
6847 {
6848 /* Strip the nops as we allow this case. FIXME, this really
6849 should be rejected or made deprecated. */
6853 }
6854 }
6855 else
6859 }
6863 /* asm statements without outputs, including simple ones, are treated
6864 as volatile. */
6869 }
6870 \f
6871 /* Generate a goto statement to LABEL. */
6873 tree
6875 {
6881 {
6884 }
6887 {
6890 }
6893 {
6894 /* No jump from outside this statement expression context, so
6895 record that there is a jump from within this context. */
6901 }
6904 {
6905 /* No jump from outside this context context of identifiers with
6906 variably modified type, so record that there is a jump from
6907 within this context. */
6913 }
6917 }
6919 /* Generate a computed goto statement to EXPR. */
6921 tree
6923 {
6928 }
6930 /* Generate a C `return' statement. RETVAL is the expression for what
6931 to return, or a null pointer for `return;' with no value. */
6933 tree
6935 {
6943 {
6947 {
6951 }
6952 }
6954 {
6960 }
6961 else
6962 {
6966 tree inner;
6974 /* Strip any conversions, additions, and subtractions, and see if
6975 we are returning the address of a local variable. Warn if so. */
6977 {
6979 {
6986 /* If the second operand of the MINUS_EXPR has a pointer
6987 type (or is converted from it), this may be valid, so
6988 don't give a warning. */
6989 {
7003 }
7021 }
7024 }
7027 }
7032 }
7033 \f
7035 /* The SWITCH_EXPR being built. */
7036 tree switch_expr;
7038 /* The original type of the testing expression, i.e. before the
7039 default conversion is applied. */
7040 tree orig_type;
7042 /* A splay-tree mapping the low element of a case range to the high
7043 element, or NULL_TREE if there is no high element. Used to
7044 determine whether or not a new case label duplicates an old case
7045 label. We need a tree, rather than simply a hash table, because
7046 of the GNU case range extension. */
7047 splay_tree cases;
7049 /* Number of nested statement expressions within this switch
7050 statement; if nonzero, case and default labels may not
7051 appear. */
7054 /* Scope of outermost declarations of identifiers with variably
7055 modified type within this switch statement; if nonzero, case and
7056 default labels may not appear. */
7059 /* The next node on the stack. */
7061 };
7063 /* A stack of the currently active switch statements. The innermost
7064 switch statement is on the top of the stack. There is no need to
7065 mark the stack for garbage collection because it is only active
7066 during the processing of the body of a function, and we never
7067 collect at that point. */
7071 /* Start a C switch statement, testing expression EXP. Return the new
7072 SWITCH_EXPR. */
7074 tree
7076 {
7081 {
7085 {
7087 {
7090 }
7092 }
7093 else
7094 {
7104 }
7105 }
7107 /* Add this new SWITCH_EXPR to the stack. */
7118 }
7120 /* Process a case label. */
7122 tree
7124 {
7129 {
7136 }
7138 {
7142 else
7145 }
7147 {
7151 else
7154 }
7157 else
7161 }
7163 /* Finish the switch statement. */
7165 void
7167 {
7169 location_t switch_location;
7173 /* We must not be within a statement expression nested in the switch
7174 at this point; we might, however, be within the scope of an
7175 identifier with variably modified type nested in the switch. */
7178 /* Emit warnings as needed. */
7181 else
7187 /* Pop the stack. */
7191 }
7192 \f
7193 /* Emit an if statement. IF_LOCUS is the location of the 'if'. COND,
7194 THEN_BLOCK and ELSE_BLOCK are expressions to be used; ELSE_BLOCK
7195 may be null. NESTED_IF is true if THEN_BLOCK contains another IF
7196 statement, and was not surrounded with parenthesis. */
7198 void
7201 {
7202 tree stmt;
7204 /* Diagnose an ambiguous else if if-then-else is nested inside if-then. */
7206 {
7209 /* We know from the grammar productions that there is an IF nested
7210 within THEN_BLOCK. Due to labels and c99 conditional declarations,
7211 it might not be exactly THEN_BLOCK, but should be the last
7212 non-container statement within. */
7215 {
7230 }
7231 found:
7237 }
7244 }
7246 /* Emit a general-purpose loop construct. START_LOCUS is the location of
7247 the beginning of the loop. COND is the loop condition. COND_IS_FIRST
7248 is false for DO loops. INCR is the FOR increment expression. BODY is
7249 the statement controlled by the loop. BLAB is the break label. CLAB is
7250 the continue label. Everything is allowed to be NULL. */
7252 void
7255 {
7258 /* If the condition is zero don't generate a loop construct. */
7260 {
7262 {
7266 }
7267 }
7268 else
7269 {
7272 /* If we have an exit condition, then we build an IF with gotos either
7273 out of the loop, or to the top of it. If there's no exit condition,
7274 then we just build a jump back to the top. */
7278 {
7279 /* Canonicalize the loop condition to the end. This means
7280 generating a branch to the loop condition. Reuse the
7281 continue label, if possible. */
7283 {
7285 {
7288 }
7289 else
7293 }
7299 else
7301 }
7304 }
7318 }
7320 tree
7322 {
7326 /* In switch statements break is sometimes stylistically used after
7327 a return statement. This can lead to spurious warnings about
7328 control reaching the end of a non-void function when it is
7329 inlined. Note that we are calling block_may_fallthru with
7330 language specific tree nodes; this works because
7331 block_may_fallthru returns true when given something it does not
7332 understand. */
7336 {
7339 }
7341 ;
7343 {
7347 else
7358 }
7364 }
7366 /* A helper routine for c_process_expr_stmt and c_finish_stmt_expr. */
7368 static void
7370 {
7372 ;
7374 {
7378 }
7379 else
7381 }
7383 /* Process an expression as if it were a complete statement. Emit
7384 diagnostics, but do not call ADD_STMT. */
7386 tree
7388 {
7400 /* If we're not processing a statement expression, warn about unused values.
7401 Warnings for statement expressions will be emitted later, once we figure
7402 out which is the result. */
7407 /* If the expression is not of a type to which we cannot assign a line
7408 number, wrap the thing in a no-op NOP_EXPR. */
7416 }
7418 /* Emit an expression as a statement. */
7420 tree
7422 {
7425 else
7427 }
7429 /* Do the opposite and emit a statement as an expression. To begin,
7430 create a new binding level and return it. */
7432 tree
7434 {
7435 tree ret;
7439 /* We must force a BLOCK for this level so that, if it is not expanded
7440 later, there is a way to turn off the entire subtree of blocks that
7441 are contained in it. */
7445 {
7448 }
7452 {
7454 }
7461 /* Mark the current statement list as belonging to a statement list. */
7465 }
7467 tree
7469 {
7476 {
7479 }
7480 /* It is no longer possible to jump to labels defined within this
7481 statement expression. */
7485 {
7487 }
7488 /* It is again possible to define labels with a goto just outside
7489 this statement expression. */
7493 {
7496 }
7499 else
7504 /* Locate the last statement in BODY. See c_end_compound_stmt
7505 about always returning a BIND_EXPR. */
7509 continue_searching:
7511 {
7512 tree_stmt_iterator i;
7514 /* This can happen with degenerate cases like ({ }). No value. */
7518 /* If we're supposed to generate side effects warnings, process
7519 all of the statements except the last. */
7521 {
7524 }
7525 else
7529 }
7531 /* If the end of the list is exception related, then the list was split
7532 by a call to push_cleanup. Continue searching. */
7535 {
7539 }
7541 /* In the case that the BIND_EXPR is not necessary, return the
7542 expression out from inside it. */
7546 {
7547 /* Do not warn if the return value of a statement expression is
7548 unused. */
7552 }
7554 /* Extract the type of said expression. */
7557 /* If we're not returning a value at all, then the BIND_EXPR that
7558 we already have is a fine expression to return. */
7562 /* Now that we've located the expression containing the value, it seems
7563 silly to make voidify_wrapper_expr repeat the process. Create a
7564 temporary of the appropriate type and stick it in a TARGET_EXPR. */
7567 /* Unwrap a no-op NOP_EXPR as added by c_finish_expr_stmt. This avoids
7568 tree_expr_nonnegative_p giving up immediately. */
7578 }
7580 /* Begin the scope of an identifier of variably modified type, scope
7581 number SCOPE. Jumping from outside this scope to inside it is not
7582 permitted. */
7584 void
7586 {
7592 /* At file_scope, we don't have to do any processing. */
7601 {
7603 }
7610 }
7612 /* End a scope which may contain identifiers of variably modified
7613 type, scope number SCOPE. */
7615 void
7617 {
7622 /* We may have a number of nested scopes of identifiers with
7623 variably modified type, all at this depth. Pop each in turn. */
7625 {
7628 /* It is no longer possible to jump to labels defined within this
7629 scope. */
7633 {
7635 }
7636 /* It is again possible to define labels with a goto just outside
7637 this scope. */
7641 {
7644 }
7647 else
7651 }
7652 }
7653 \f
7654 /* Begin and end compound statements. This is as simple as pushing
7655 and popping new statement lists from the tree. */
7657 tree
7659 {
7664 }
7666 tree
7668 {
7672 {
7676 }
7681 /* If this compound statement is nested immediately inside a statement
7682 expression, then force a BIND_EXPR to be created. Otherwise we'll
7683 do the wrong thing for ({ { 1; } }) or ({ 1; { } }). In particular,
7684 STATEMENT_LISTs merge, and thus we can lose track of what statement
7685 was really last. */
7689 {
7692 }
7695 }
7697 /* Queue a cleanup. CLEANUP is an expression/statement to be executed
7698 when the current scope is exited. EH_ONLY is true when this is not
7699 meant to apply to normal control flow transfer. */
7701 void
7703 {
7715 }
7716 \f
7717 /* Build a binary-operation expression without default conversions.
7718 CODE is the kind of expression to build.
7719 This function differs from `build' in several ways:
7720 the data type of the result is computed and recorded in it,
7721 warnings are generated if arg data types are invalid,
7722 special handling for addition and subtraction of pointers is known,
7723 and some optimization is done (operations on narrow ints
7724 are done in the narrower type when that gives the same result).
7725 Constant folding is also done before the result is returned.
7727 Note that the operands will never have enumeral types, or function
7728 or array types, because either they will have the default conversions
7729 performed or they have both just been converted to some other type in which
7730 the arithmetic is to be done. */
7732 tree
7735 {
7741 /* Expression code to give to the expression when it is built.
7742 Normally this is CODE, which is what the caller asked for,
7743 but in some special cases we change it. */
7746 /* Data type in which the computation is to be performed.
7747 In the simplest cases this is the common type of the arguments. */
7750 /* Nonzero means operands have already been type-converted
7751 in whatever way is necessary.
7752 Zero means they need to be converted to RESULT_TYPE. */
7755 /* Nonzero means create the expression with this type, rather than
7756 RESULT_TYPE. */
7759 /* Nonzero means after finally constructing the expression
7760 convert it to this type. */
7763 /* Nonzero if this is an operation like MIN or MAX which can
7764 safely be computed in short if both args are promoted shorts.
7765 Also implies COMMON.
7766 -1 indicates a bitwise operation; this makes a difference
7767 in the exact conditions for when it is safe to do the operation
7768 in a narrower mode. */
7771 /* Nonzero if this is a comparison operation;
7772 if both args are promoted shorts, compare the original shorts.
7773 Also implies COMMON. */
7776 /* Nonzero if this is a right-shift operation, which can be computed on the
7777 original short and then promoted if the operand is a promoted short. */
7780 /* Nonzero means set RESULT_TYPE to the common type of the args. */
7783 /* True means types are compatible as far as ObjC is concerned. */
7787 {
7790 }
7791 else
7792 {
7795 }
7800 /* The expression codes of the data types of the arguments tell us
7801 whether the arguments are integers, floating, pointers, etc. */
7805 /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue. */
7809 /* If an error was already reported for one of the arguments,
7810 avoid reporting another error. */
7817 {
7820 }
7825 {
7827 /* Handle the pointer + int case. */
7832 else
7837 /* Subtraction of two similar pointers.
7838 We must subtract them as integers, then divide by object size. */
7842 /* Handle pointer minus int. Just like pointer plus int. */
7845 else
7864 {
7874 else
7875 /* Although it would be tempting to shorten always here, that
7876 loses on some targets, since the modulo instruction is
7877 undefined if the quotient can't be represented in the
7878 computation mode. We shorten only if unsigned or if
7879 dividing by something we know != -1. */
7884 }
7901 {
7902 /* Although it would be tempting to shorten always here, that loses
7903 on some targets, since the modulo instruction is undefined if the
7904 quotient can't be represented in the computation mode. We shorten
7905 only if unsigned or if dividing by something we know != -1. */
7910 }
7922 {
7923 /* Result of these operations is always an int,
7924 but that does not mean the operands should be
7925 converted to ints! */
7930 }
7933 /* Shift operations: result has same type as first operand;
7934 always convert second operand to int.
7935 Also set SHORT_SHIFT if shifting rightward. */
7939 {
7941 {
7944 else
7945 {
7951 }
7952 }
7954 /* Use the type of the value to be shifted. */
7956 /* Convert the shift-count to an integer, regardless of size
7957 of value being shifted. */
7960 /* Avoid converting op1 to result_type later. */
7962 }
7967 {
7969 {
7975 }
7977 /* Use the type of the value to be shifted. */
7979 /* Convert the shift-count to an integer, regardless of size
7980 of value being shifted. */
7983 /* Avoid converting op1 to result_type later. */
7985 }
7993 /* Result of comparison is always int,
7994 but don't convert the args to int! */
8002 {
8005 /* Anything compares with void *. void * compares with anything.
8006 Otherwise, the targets must be compatible
8007 and both must be object or both incomplete. */
8011 {
8012 /* op0 != orig_op0 detects the case of something
8013 whose value is 0 but which isn't a valid null ptr const. */
8018 }
8020 {
8025 }
8026 else
8027 /* Avoid warning about the volatile ObjC EH puts on decls. */
8033 }
8035 {
8041 }
8043 {
8049 }
8051 {
8054 }
8056 {
8059 }
8071 {
8073 {
8081 }
8082 else
8083 {
8086 }
8087 }
8089 {
8093 }
8095 {
8099 }
8101 {
8104 }
8106 {
8109 }
8114 }
8123 {
8126 }
8130 &&
8133 {
8139 /* For certain operations (which identify themselves by shorten != 0)
8140 if both args were extended from the same smaller type,
8141 do the arithmetic in that type and then extend.
8143 shorten !=0 and !=1 indicates a bitwise operation.
8144 For them, this optimization is safe only if
8145 both args are zero-extended or both are sign-extended.
8146 Otherwise, we might change the result.
8147 Eg, (short)-1 | (unsigned short)-1 is (int)-1
8148 but calculated in (unsigned short) it would be (unsigned short)-1. */
8151 {
8155 tree type;
8157 /* Cast OP0 and OP1 to RESULT_TYPE. Doing so prevents
8158 excessive narrowing when we call get_narrower below. For
8159 example, suppose that OP0 is of unsigned int extended
8160 from signed char and that RESULT_TYPE is long long int.
8161 If we explicitly cast OP0 to RESULT_TYPE, OP0 would look
8162 like
8164 (long long int) (unsigned int) signed_char
8166 which get_narrower would narrow down to
8168 (unsigned int) signed char
8170 If we do not cast OP0 first, get_narrower would return
8171 signed_char, which is inconsistent with the case of the
8172 explicit cast. */
8179 /* UNS is 1 if the operation to be done is an unsigned one. */
8184 /* Handle the case that OP0 (or OP1) does not *contain* a conversion
8185 but it *requires* conversion to FINAL_TYPE. */
8196 /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE. */
8198 /* For bitwise operations, signedness of nominal type
8199 does not matter. Consider only how operands were extended. */
8203 /* Note that in all three cases below we refrain from optimizing
8204 an unsigned operation on sign-extended args.
8205 That would not be valid. */
8207 /* Both args variable: if both extended in same way
8208 from same width, do it in that width.
8209 Do it unsigned if args were zero-extended. */
8216 result_type
8217 = c_common_signed_or_unsigned_type
8223 && (type
8232 && (type
8237 }
8239 /* Shifts can be shortened if shifting right. */
8242 {
8252 /* We can shorten only if the shift count is less than the
8253 number of bits in the smaller type size. */
8255 /* We cannot drop an unsigned shift after sign-extension. */
8257 {
8258 /* Do an unsigned shift if the operand was zero-extended. */
8259 result_type
8262 /* Convert value-to-be-shifted to that type. */
8266 }
8267 }
8269 /* Comparison operations are shortened too but differently.
8270 They identify themselves by setting short_compare = 1. */
8273 {
8274 /* Don't write &op0, etc., because that would prevent op0
8275 from being kept in a register.
8276 Instead, make copies of the our local variables and
8277 pass the copies by reference, then copy them back afterward. */
8280 tree val
8291 {
8303 /* Give warnings for comparisons between signed and unsigned
8304 quantities that may fail.
8306 Do the checking based on the original operand trees, so that
8307 casts will be considered, but default promotions won't be.
8309 Do not warn if the comparison is being done in a signed type,
8310 since the signed type will only be chosen if it can represent
8311 all the values of the unsigned type. */
8314 /* Do not warn if both operands are the same signedness. */
8317 else
8318 {
8324 else
8327 /* Do not warn if the signed quantity is an
8328 unsuffixed integer literal (or some static
8329 constant expression involving such literals or a
8330 conditional expression involving such literals)
8331 and it is non-negative. */
8334 /* Do not warn if the comparison is an equality operation,
8335 the unsigned quantity is an integral constant, and it
8336 would fit in the result if the result were signed. */
8339 && int_fits_type_p
8342 /* Do not warn if the unsigned quantity is an enumeration
8343 constant and its maximum value would fit in the result
8344 if the result were signed. */
8347 && int_fits_type_p
8351 else
8353 }
8355 /* Warn if two unsigned values are being compared in a size
8356 larger than their original size, and one (and only one) is the
8357 result of a `~' operator. This comparison will always fail.
8359 Also warn if one operand is a constant, and the constant
8360 does not have all bits set that are set in the ~ operand
8361 when it is extended. */
8365 {
8369 else
8374 {
8375 tree primop;
8380 {
8384 }
8385 else
8386 {
8390 }
8395 {
8399 }
8400 }
8407 }
8408 }
8409 }
8410 }
8412 /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
8413 If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
8414 Then the expression will be built.
8415 It will be given type FINAL_TYPE if that is nonzero;
8416 otherwise, it will be given type RESULT_TYPE. */
8419 {
8422 }
8425 {
8431 /* This can happen if one operand has a vector type, and the other
8432 has a different type. */
8435 }
8440 {
8441 /* Treat expressions in initializers specially as they can't trap. */
8443 build_type,
8451 }
8452 }
8455 /* Convert EXPR to be a truth-value, validating its type for this
8456 purpose. */
8458 tree
8460 {
8462 {
8480 }
8482 /* ??? Should we also give an error for void and vectors rather than
8483 leaving those to give errors later? */
8485 }
8486 \f
8488 /* Convert EXPR to a contained DECL, updating *TC, *TI and *SE as
8489 required. */
8491 tree
8494 {
8496 {
8498 /* Executing a compound literal inside a function reinitializes
8499 it. */
8503 }
8504 else
8506 }
8507 \f
8508 /* Like c_begin_compound_stmt, except force the retention of the BLOCK. */
8510 tree
8512 {
8513 tree block;
8519 }
8521 tree
8523 {
8524 tree stmt;
8534 }
8536 /* For all elements of CLAUSES, validate them vs OpenMP constraints.
8537 Remove any elements from the list that are invalid. */
8539 tree
8541 {
8552 {
8558 {
8576 {
8579 }
8581 {
8586 {
8608 }
8610 {
8614 }
8615 }
8626 {
8629 }
8632 check_dup_generic:
8635 {
8638 }
8642 {
8645 }
8646 else
8656 {
8659 }
8662 {
8665 }
8666 else
8676 {
8679 }
8682 {
8685 }
8686 else
8701 }
8704 {
8708 {
8712 }
8715 {
8721 {
8732 }
8734 {
8738 }
8739 }
8740 }
8744 else
8746 }
8750 }