1 /* Encoding of types for Objective C.
2 Copyright (C) 1993, 1995, 1996, 1997, 1998, 2000, 2002, 2004, 2009
3 Free Software Foundation, Inc.
4 Contributed by Kresten Krab Thorup
5 Bitfield support by Ovidiu Predescu
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 Under Section 7 of GPL version 3, you are granted additional
20 permissions described in the GCC Runtime Library Exception, version
21 3.1, as published by the Free Software Foundation.
23 You should have received a copy of the GNU General Public License and
24 a copy of the GCC Runtime Library Exception along with this program;
25 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
26 <http://www.gnu.org/licenses/>. */
28 /* FIXME: This file has no business including tm.h. */
30 #include "objc-private/common.h"
32 #include "coretypes.h"
34 #include "objc/objc-api.h"
35 #include "objc/encoding.h"
40 ({ typeof (X) __x = (X), __y = (Y); \
41 (__x > __y ? __x : __y); })
45 ({ typeof (X) __x = (X), __y = (Y); \
46 (__x < __y ? __x : __y); })
50 ({ typeof (V) __v = (V); typeof (A) __a = (A); \
51 __a * ((__v+__a - 1)/__a); })
54 /* Various hacks for objc_layout_record. These are used by the target
57 #define TREE_CODE(TYPE) *(TYPE)
58 #define TREE_TYPE(TREE) (TREE)
60 #define RECORD_TYPE _C_STRUCT_B
61 #define UNION_TYPE _C_UNION_B
62 #define QUAL_UNION_TYPE _C_UNION_B
63 #define ARRAY_TYPE _C_ARY_B
65 #define REAL_TYPE _C_DBL
67 #define VECTOR_TYPE _C_VECTOR
69 #define TYPE_FIELDS(TYPE) ({const char *_field = (TYPE)+1; \
70 while (*_field != _C_STRUCT_E && *_field != _C_STRUCT_B \
71 && *_field != _C_UNION_B && *_field++ != '=') \
75 #define DECL_MODE(TYPE) *(TYPE)
76 #define TYPE_MODE(TYPE) *(TYPE)
80 #define strip_array_types(TYPE) ({const char *_field = (TYPE); \
81 while (*_field == _C_ARY_B)\
83 while (isdigit ((unsigned char)*++_field))\
88 /* Some ports (eg ARM) allow the structure size boundary to be
89 selected at compile-time. We override the normal definition with
90 one that has a constant value for this compilation. */
92 #define BITS_PER_UNIT 8
94 #undef STRUCTURE_SIZE_BOUNDARY
95 #define STRUCTURE_SIZE_BOUNDARY (BITS_PER_UNIT * sizeof (struct{char a;}))
97 /* Some ROUND_TYPE_ALIGN macros use TARGET_foo, and consequently
98 target_flags. Define a dummy entry here to so we don't die.
99 We have to rename it because target_flags may already have been
101 #define target_flags not_target_flags
102 static int __attribute__ ((__unused__)) not_target_flags = 0;
104 /* Some ROUND_TYPE_ALIGN use ALTIVEC_VECTOR_MODE (rs6000 darwin).
105 Define a dummy ALTIVEC_VECTOR_MODE so it will not die. */
106 #undef ALTIVEC_VECTOR_MODE
107 #define ALTIVEC_VECTOR_MODE(MODE) (0)
109 /* Furthermore, some (powerpc) targets also use TARGET_ALIGN_NATURAL
110 in their alignment macros. Currently[4.5/6], rs6000.h points this
111 to a static variable, initialized by target overrides. This is reset
112 in linux64.h but not in darwin64.h. The macro is not used by *86*. */
114 #if __MACH__ && __LP64__
115 # undef TARGET_ALIGN_NATURAL
116 # define TARGET_ALIGN_NATURAL 1
119 /* FIXME: while this file has no business including tm.h, this
120 definitely has no business defining this macro but it
121 is only way around without really rewritting this file,
122 should look after the branch of 3.4 to fix this.
123 FIXME1: It's also out of date, darwin no longer has the same alignment
124 'special' as aix - this is probably the origin of the m32 breakage. */
125 #define rs6000_special_round_type_align(STRUCT, COMPUTED, SPECIFIED) \
126 ({ const char *_fields = TYPE_FIELDS (STRUCT); \
128 && TYPE_MODE (strip_array_types (TREE_TYPE (_fields))) == DFmode) \
129 ? MAX (MAX (COMPUTED, SPECIFIED), 64) \
130 : MAX (COMPUTED, SPECIFIED));})
131 /* FIXME: The word 'fixme' is insufficient to explain the wrong-ness
132 of this next macro definition. */
133 #define darwin_rs6000_special_round_type_align(S,C,S2) \
134 rs6000_special_round_type_align(S,C,S2)
137 return the size of an object specified by type
141 objc_sizeof_type (const char *type)
143 /* Skip the variable name if any */
146 for (type++; *type++ != '"';)
152 return sizeof (_Bool);
160 return sizeof (Class);
168 return sizeof (char);
172 return sizeof (unsigned char);
176 return sizeof (short);
180 return sizeof (unsigned short);
188 return sizeof (unsigned int);
192 return sizeof (long);
196 return sizeof (unsigned long);
200 return sizeof (long long);
204 return sizeof (unsigned long long);
208 return sizeof (float);
212 return sizeof (double);
216 return sizeof (void);
222 return sizeof (char *);
227 int len = atoi (type + 1);
228 while (isdigit ((unsigned char)*++type))
230 return len * objc_aligned_size (type);
236 /* The new encoding of bitfields is: b 'position' 'type' 'size' */
238 int startByte, endByte;
240 position = atoi (type + 1);
241 while (isdigit ((unsigned char)*++type))
243 size = atoi (type + 1);
245 startByte = position / BITS_PER_UNIT;
246 endByte = (position + size) / BITS_PER_UNIT;
247 return endByte - startByte;
253 struct objc_struct_layout layout;
256 objc_layout_structure (type, &layout);
257 while (objc_layout_structure_next_member (&layout))
259 objc_layout_finish_structure (&layout, &size, NULL);
266 type++; /* Skip after the 'j'. */
270 return sizeof (_Complex char);
274 return sizeof (_Complex unsigned char);
278 return sizeof (_Complex short);
282 return sizeof (_Complex unsigned short);
286 return sizeof (_Complex int);
290 return sizeof (_Complex unsigned int);
294 return sizeof (_Complex long);
298 return sizeof (_Complex unsigned long);
302 return sizeof (_Complex long long);
306 return sizeof (_Complex unsigned long long);
310 return sizeof (_Complex float);
314 return sizeof (_Complex double);
319 objc_error (nil, OBJC_ERR_BAD_TYPE, "unknown complex type %s\n",
328 objc_error (nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
336 Return the alignment of an object specified by type
340 objc_alignof_type (const char *type)
342 /* Skip the variable name if any */
345 for (type++; *type++ != '"';)
350 return __alignof__ (_Bool);
354 return __alignof__ (id);
358 return __alignof__ (Class);
362 return __alignof__ (SEL);
366 return __alignof__ (char);
370 return __alignof__ (unsigned char);
374 return __alignof__ (short);
378 return __alignof__ (unsigned short);
382 return __alignof__ (int);
386 return __alignof__ (unsigned int);
390 return __alignof__ (long);
394 return __alignof__ (unsigned long);
398 return __alignof__ (long long);
402 return __alignof__ (unsigned long long);
406 return __alignof__ (float);
410 return __alignof__ (double);
416 return __alignof__ (char *);
420 while (isdigit ((unsigned char)*++type))
422 return objc_alignof_type (type);
427 struct objc_struct_layout layout;
430 objc_layout_structure (type, &layout);
431 while (objc_layout_structure_next_member (&layout))
433 objc_layout_finish_structure (&layout, NULL, &align);
441 type++; /* Skip after the 'j'. */
445 return __alignof__ (_Complex char);
449 return __alignof__ (_Complex unsigned char);
453 return __alignof__ (_Complex short);
457 return __alignof__ (_Complex unsigned short);
461 return __alignof__ (_Complex int);
465 return __alignof__ (_Complex unsigned int);
469 return __alignof__ (_Complex long);
473 return __alignof__ (_Complex unsigned long);
477 return __alignof__ (_Complex long long);
481 return __alignof__ (_Complex unsigned long long);
485 return __alignof__ (_Complex float);
489 return __alignof__ (_Complex double);
494 objc_error (nil, OBJC_ERR_BAD_TYPE, "unknown complex type %s\n",
503 objc_error (nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
510 The aligned size if the size rounded up to the nearest alignment.
514 objc_aligned_size (const char *type)
518 /* Skip the variable name */
521 for (type++; *type++ != '"';)
525 size = objc_sizeof_type (type);
526 align = objc_alignof_type (type);
528 return ROUND (size, align);
532 The size rounded up to the nearest integral of the wordsize, taken
533 to be the size of a void *.
537 objc_promoted_size (const char *type)
541 /* Skip the variable name */
544 for (type++; *type++ != '"';)
548 size = objc_sizeof_type (type);
549 wordsize = sizeof (void *);
551 return ROUND (size, wordsize);
555 Skip type qualifiers. These may eventually precede typespecs
556 occurring in method prototype encodings.
560 objc_skip_type_qualifiers (const char *type)
562 while (*type == _C_CONST
566 || *type == _C_BYCOPY
568 || *type == _C_ONEWAY
569 || *type == _C_GCINVISIBLE)
578 Skip one typespec element. If the typespec is prepended by type
579 qualifiers, these are skipped as well.
583 objc_skip_typespec (const char *type)
585 /* Skip the variable name if any */
588 for (type++; *type++ != '"';)
592 type = objc_skip_type_qualifiers (type);
597 /* An id may be annotated by the actual type if it is known
598 with the @"ClassName" syntax */
604 while (*++type != '"')
609 /* The following are one character type codes */
637 /* skip digits, typespec and closing ']' */
639 while (isdigit ((unsigned char)*++type))
641 type = objc_skip_typespec (type);
642 if (*type == _C_ARY_E)
646 objc_error (nil, OBJC_ERR_BAD_TYPE, "bad array type %s\n", type);
651 /* The new encoding of bitfields is: b 'position' 'type' 'size' */
652 while (isdigit ((unsigned char)*++type))
653 ; /* skip position */
654 while (isdigit ((unsigned char)*++type))
655 ; /* skip type and size */
659 /* skip name, and elements until closing '}' */
661 while (*type != _C_STRUCT_E && *type++ != '=')
663 while (*type != _C_STRUCT_E)
665 type = objc_skip_typespec (type);
670 /* skip name, and elements until closing ')' */
672 while (*type != _C_UNION_E && *type++ != '=')
674 while (*type != _C_UNION_E)
676 type = objc_skip_typespec (type);
681 /* Just skip the following typespec */
683 return objc_skip_typespec (++type);
687 objc_error (nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
694 Skip an offset as part of a method encoding. This is prepended by a
695 '+' if the argument is passed in registers.
698 objc_skip_offset (const char *type)
702 while (isdigit ((unsigned char) *++type))
708 Skip an argument specification of a method encoding.
711 objc_skip_argspec (const char *type)
713 type = objc_skip_typespec (type);
714 type = objc_skip_offset (type);
719 Return the number of arguments that the method MTH expects.
720 Note that all methods need two implicit arguments `self' and
724 method_get_number_of_arguments (struct objc_method *mth)
727 const char *type = mth->method_types;
730 type = objc_skip_argspec (type);
737 Return the size of the argument block needed on the stack to invoke
738 the method MTH. This may be zero, if all arguments are passed in
743 method_get_sizeof_arguments (struct objc_method *mth)
745 const char *type = objc_skip_typespec (mth->method_types);
750 Return a pointer to the next argument of ARGFRAME. type points to
751 the last argument. Typical use of this look like:
755 for (datum = method_get_first_argument (method, argframe, &type);
756 datum; datum = method_get_next_argument (argframe, &type))
758 unsigned flags = objc_get_type_qualifiers (type);
759 type = objc_skip_type_qualifiers (type);
761 [portal encodeData: datum ofType: type];
764 if ((flags & _F_IN) == _F_IN)
765 [portal encodeData: *(char **) datum ofType: ++type];
772 method_get_next_argument (arglist_t argframe, const char **type)
774 const char *t = objc_skip_argspec (*type);
780 t = objc_skip_typespec (t);
783 return argframe->arg_regs + atoi (++t);
785 return argframe->arg_ptr + atoi (t);
789 Return a pointer to the value of the first argument of the method
790 described in M with the given argumentframe ARGFRAME. The type
791 is returned in TYPE. type must be passed to successive calls of
792 method_get_next_argument.
795 method_get_first_argument (struct objc_method *m,
799 *type = m->method_types;
800 return method_get_next_argument (argframe, type);
804 Return a pointer to the ARGth argument of the method
805 M from the frame ARGFRAME. The type of the argument
806 is returned in the value-result argument TYPE
810 method_get_nth_argument (struct objc_method *m,
811 arglist_t argframe, int arg,
814 const char *t = objc_skip_argspec (m->method_types);
816 if (arg > method_get_number_of_arguments (m))
820 t = objc_skip_argspec (t);
823 t = objc_skip_typespec (t);
826 return argframe->arg_regs + atoi (++t);
828 return argframe->arg_ptr + atoi (t);
832 objc_get_type_qualifiers (const char *type)
840 case _C_CONST: res |= _F_CONST; break;
841 case _C_IN: res |= _F_IN; break;
842 case _C_INOUT: res |= _F_INOUT; break;
843 case _C_OUT: res |= _F_OUT; break;
844 case _C_BYCOPY: res |= _F_BYCOPY; break;
845 case _C_BYREF: res |= _F_BYREF; break;
846 case _C_ONEWAY: res |= _F_ONEWAY; break;
847 case _C_GCINVISIBLE: res |= _F_GCINVISIBLE; break;
855 /* The following three functions can be used to determine how a
856 structure is laid out by the compiler. For example:
858 struct objc_struct_layout layout;
861 objc_layout_structure (type, &layout);
862 while (objc_layout_structure_next_member (&layout))
867 objc_layout_structure_get_info (&layout, &position, &align, &type);
868 printf ("element %d has offset %d, alignment %d\n",
869 i++, position, align);
872 These functions are used by objc_sizeof_type and objc_alignof_type
873 functions to compute the size and alignment of structures. The
874 previous method of computing the size and alignment of a structure
875 was not working on some architectures, particulary on AIX, and in
876 the presence of bitfields inside the structure. */
878 objc_layout_structure (const char *type,
879 struct objc_struct_layout *layout)
883 if (*type != _C_UNION_B && *type != _C_STRUCT_B)
885 objc_error (nil, OBJC_ERR_BAD_TYPE,
886 "record (or union) type expected in objc_layout_structure, got %s\n",
891 layout->original_type = type;
893 /* Skip "<name>=" if any. Avoid embedded structures and unions. */
895 while (*ntype != _C_STRUCT_E && *ntype != _C_STRUCT_B && *ntype != _C_UNION_B
899 /* If there's a "<name>=", ntype - 1 points to '='; skip the the name */
900 if (*(ntype - 1) == '=')
904 layout->prev_type = NULL;
905 layout->record_size = 0;
906 layout->record_align = BITS_PER_UNIT;
908 layout->record_align = MAX (layout->record_align, STRUCTURE_SIZE_BOUNDARY);
913 objc_layout_structure_next_member (struct objc_struct_layout *layout)
915 register int desired_align = 0;
917 /* The following are used only if the field is a bitfield */
918 register const char *bfld_type = 0;
919 register int bfld_type_align = 0, bfld_field_size = 0;
921 /* The current type without the type qualifiers */
923 BOOL unionp = layout->original_type[-1] == _C_UNION_B;
925 /* Add the size of the previous field to the size of the record. */
926 if (layout->prev_type)
928 type = objc_skip_type_qualifiers (layout->prev_type);
930 layout->record_size = MAX (layout->record_size,
931 objc_sizeof_type (type) * BITS_PER_UNIT);
933 else if (*type != _C_BFLD)
934 layout->record_size += objc_sizeof_type (type) * BITS_PER_UNIT;
936 /* Get the bitfield's type */
937 for (bfld_type = type + 1;
938 isdigit ((unsigned char)*bfld_type);
942 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
943 bfld_field_size = atoi (objc_skip_typespec (bfld_type));
944 layout->record_size += bfld_field_size;
948 if ((unionp && *layout->type == _C_UNION_E)
949 || (!unionp && *layout->type == _C_STRUCT_E))
952 /* Skip the variable name if any */
953 if (*layout->type == '"')
955 for (layout->type++; *layout->type++ != '"';)
959 type = objc_skip_type_qualifiers (layout->type);
961 if (*type != _C_BFLD)
962 desired_align = objc_alignof_type (type) * BITS_PER_UNIT;
966 /* Skip the bitfield's offset */
967 for (bfld_type = type + 1;
968 isdigit ((unsigned char) *bfld_type);
972 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
973 bfld_field_size = atoi (objc_skip_typespec (bfld_type));
976 #ifdef BIGGEST_FIELD_ALIGNMENT
977 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
979 #ifdef ADJUST_FIELD_ALIGN
980 desired_align = ADJUST_FIELD_ALIGN (type, desired_align);
983 /* Record must have at least as much alignment as any field.
984 Otherwise, the alignment of the field within the record
986 #ifndef PCC_BITFIELD_TYPE_MATTERS
987 layout->record_align = MAX (layout->record_align, desired_align);
988 #else /* PCC_BITFIELD_TYPE_MATTERS */
989 if (*type == _C_BFLD)
991 /* For these machines, a zero-length field does not
992 affect the alignment of the structure as a whole.
993 It does, however, affect the alignment of the next field
994 within the structure. */
996 layout->record_align = MAX (layout->record_align, desired_align);
998 desired_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
1000 /* A named bit field of declared type `int'
1001 forces the entire structure to have `int' alignment.
1002 Q1: How is encoded this thing and how to check for it?
1003 Q2: How to determine maximum_field_alignment at runtime? */
1005 /* if (DECL_NAME (field) != 0) */
1007 int type_align = bfld_type_align;
1009 if (maximum_field_alignment != 0)
1010 type_align = MIN (type_align, maximum_field_alignment);
1011 else if (DECL_PACKED (field))
1012 type_align = MIN (type_align, BITS_PER_UNIT);
1015 layout->record_align = MAX (layout->record_align, type_align);
1019 layout->record_align = MAX (layout->record_align, desired_align);
1020 #endif /* PCC_BITFIELD_TYPE_MATTERS */
1022 /* Does this field automatically have alignment it needs
1023 by virtue of the fields that precede it and the record's
1026 if (*type == _C_BFLD)
1027 layout->record_size = atoi (type + 1);
1028 else if (layout->record_size % desired_align != 0)
1030 /* No, we need to skip space before this field.
1031 Bump the cumulative size to multiple of field alignment. */
1032 layout->record_size = ROUND (layout->record_size, desired_align);
1035 /* Jump to the next field in record. */
1037 layout->prev_type = layout->type;
1038 layout->type = objc_skip_typespec (layout->type); /* skip component */
1044 void objc_layout_finish_structure (struct objc_struct_layout *layout,
1046 unsigned int *align)
1048 BOOL unionp = layout->original_type[-1] == _C_UNION_B;
1050 && ((!unionp && *layout->type == _C_STRUCT_E)
1051 || (unionp && *layout->type == _C_UNION_E)))
1053 /* Work out the alignment of the record as one expression and store
1054 in the record type. Round it up to a multiple of the record's
1056 #if defined (ROUND_TYPE_ALIGN) && ! defined (__sparc__)
1057 layout->record_align = ROUND_TYPE_ALIGN (layout->original_type-1,
1059 layout->record_align);
1061 layout->record_align = MAX (1, layout->record_align);
1064 #ifdef ROUND_TYPE_SIZE
1065 layout->record_size = ROUND_TYPE_SIZE (layout->original_type,
1066 layout->record_size,
1067 layout->record_align);
1069 /* Round the size up to be a multiple of the required alignment */
1070 layout->record_size = ROUND (layout->record_size, layout->record_align);
1073 layout->type = NULL;
1076 *size = layout->record_size / BITS_PER_UNIT;
1078 *align = layout->record_align / BITS_PER_UNIT;
1082 void objc_layout_structure_get_info (struct objc_struct_layout *layout,
1083 unsigned int *offset,
1084 unsigned int *align,
1088 *offset = layout->record_size / BITS_PER_UNIT;
1090 *align = layout->record_align / BITS_PER_UNIT;
1092 *type = layout->prev_type;