1 /* Encoding of types for Objective C.
2 Copyright (C) 1993, 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
3 Contributed by Kresten Krab Thorup
4 Bitfield support by Ovidiu Predescu
6 This file is part of GNU CC.
8 GNU CC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GNU CC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GNU CC; see the file COPYING. If not, write to
20 the Free Software Foundation, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
23 /* As a special exception, if you link this library with files
24 compiled with GCC to produce an executable, this does not cause
25 the resulting executable to be covered by the GNU General Public License.
26 This exception does not however invalidate any other reasons why
27 the executable file might be covered by the GNU General Public License. */
29 #include "compiler-info.h"
34 ({ typeof(X) __x = (X), __y = (Y); \
35 (__x > __y ? __x : __y); })
38 ({ typeof(X) __x = (X), __y = (Y); \
39 (__x < __y ? __x : __y); })
42 ({ typeof(V) __v=(V); typeof(A) __a=(A); \
43 __a*((__v+__a-1)/__a); })
46 /* Various hacks for objc_layout_record. These are used by the target
49 #define TREE_CODE(TYPE) *TYPE
50 #define TREE_TYPE(TREE) TREE
52 #define RECORD_TYPE _C_STRUCT_B
53 #define UNION_TYPE _C_UNION_B
54 #define QUAL_UNION_TYPE _C_UNION_B
55 #define ARRAY_TYPE _C_ARY_B
57 #define TYPE_FIELDS(TYPE) objc_skip_typespec (TYPE)
59 #define DECL_MODE(TYPE) *(TYPE)
63 #define get_inner_array_type(TYPE) ((TYPE) + 1)
66 static __inline__ int objc_atoi(register const char* str) {
69 while (isdigit ((int)*str))
70 res *= 10, res += (*str++ - '0');
76 return the size of an object specified by type
79 int objc_sizeof_type (const char* type) {
80 /* Skip the variable name if any */
83 for (type++; *type++ != '"';)
105 return sizeof(unsigned char);
109 return sizeof(short);
113 return sizeof(unsigned short);
121 return sizeof(unsigned int);
129 return sizeof(unsigned long);
133 return sizeof(long long);
137 return sizeof(unsigned long long);
141 return sizeof(float);
145 return sizeof(double);
154 return sizeof(char*);
159 int len = objc_atoi(type+1);
160 while (isdigit((int)*++type));
161 return len*objc_aligned_size (type);
167 /* The new encoding of bitfields is: b 'position' 'type' 'size' */
169 int startByte, endByte;
171 position = objc_atoi (type + 1);
172 while (isdigit ((int)*++type));
173 size = objc_atoi (type + 1);
175 startByte = position / BITS_PER_UNIT;
176 endByte = (position + size) / BITS_PER_UNIT;
177 return endByte - startByte;
182 struct objc_struct_layout layout;
185 objc_layout_structure (type, &layout);
186 while (objc_layout_structure_next_member (&layout))
188 objc_layout_finish_structure (&layout, &size, NULL);
196 while (*type != _C_UNION_E && *type++ != '=') /* do nothing */;
197 while (*type != _C_UNION_E)
199 /* Skip the variable name if any */
202 for (type++; *type++ != '"';)
205 max_size = MAX (max_size, objc_sizeof_type (type));
206 type = objc_skip_typespec (type);
213 objc_error(nil, OBJC_ERR_BAD_TYPE, "%s: unknown type %s\n",
214 __PRETTY_FUNCTION__, type);
222 Return the alignment of an object specified by type
226 objc_alignof_type(const char* type)
228 /* Skip the variable name if any */
231 for (type++; *type++ != '"';)
236 return __alignof__(id);
240 return __alignof__(Class);
244 return __alignof__(SEL);
248 return __alignof__(char);
252 return __alignof__(unsigned char);
256 return __alignof__(short);
260 return __alignof__(unsigned short);
264 return __alignof__(int);
268 return __alignof__(unsigned int);
272 return __alignof__(long);
276 return __alignof__(unsigned long);
280 return __alignof__(long long);
284 return __alignof__(unsigned long long);
288 return __alignof__(float);
292 return __alignof__(double);
298 return __alignof__(char*);
302 while (isdigit((int)*++type)) /* do nothing */;
303 return objc_alignof_type (type);
307 struct objc_struct_layout layout;
310 objc_layout_structure (type, &layout);
311 while (objc_layout_structure_next_member (&layout))
313 objc_layout_finish_structure (&layout, NULL, &align);
321 while (*type != _C_UNION_E && *type++ != '=') /* do nothing */;
322 while (*type != _C_UNION_E)
324 /* Skip the variable name if any */
327 for (type++; *type++ != '"';)
330 maxalign = MAX (maxalign, objc_alignof_type (type));
331 type = objc_skip_typespec (type);
338 objc_error(nil, OBJC_ERR_BAD_TYPE, "%s: unknown type %s\n",
339 __PRETTY_FUNCTION__, type);
346 The aligned size if the size rounded up to the nearest alignment.
350 objc_aligned_size (const char* type)
354 /* Skip the variable name */
357 for (type++; *type++ != '"';)
361 size = objc_sizeof_type (type);
362 align = objc_alignof_type (type);
364 return ROUND (size, align);
368 The size rounded up to the nearest integral of the wordsize, taken
369 to be the size of a void*.
373 objc_promoted_size (const char* type)
377 /* Skip the variable name */
380 for (type++; *type++ != '"';)
384 size = objc_sizeof_type (type);
385 wordsize = sizeof (void*);
387 return ROUND (size, wordsize);
391 Skip type qualifiers. These may eventually precede typespecs
392 occurring in method prototype encodings.
395 __inline__ const char*
396 objc_skip_type_qualifiers (const char* type)
398 while (*type == _C_CONST
402 || *type == _C_BYCOPY
404 || *type == _C_ONEWAY
405 || *type == _C_GCINVISIBLE)
414 Skip one typespec element. If the typespec is prepended by type
415 qualifiers, these are skipped as well.
419 objc_skip_typespec (const char* type)
421 /* Skip the variable name if any */
424 for (type++; *type++ != '"';)
428 type = objc_skip_type_qualifiers (type);
433 /* An id may be annotated by the actual type if it is known
434 with the @"ClassName" syntax */
440 while (*++type != '"') /* do nothing */;
444 /* The following are one character type codes */
467 /* skip digits, typespec and closing ']' */
469 while(isdigit((int)*++type));
470 type = objc_skip_typespec(type);
471 if (*type == _C_ARY_E)
475 objc_error(nil, OBJC_ERR_BAD_TYPE, "bad array type %s\n", type);
480 /* The new encoding of bitfields is: b 'position' 'type' 'size' */
481 while (isdigit ((int)*++type)); /* skip position */
482 while (isdigit ((int)*++type)); /* skip type and size */
486 /* skip name, and elements until closing '}' */
488 while (*type != _C_STRUCT_E && *type++ != '=');
489 while (*type != _C_STRUCT_E) { type = objc_skip_typespec (type); }
493 /* skip name, and elements until closing ')' */
495 while (*type != _C_UNION_E && *type++ != '=');
496 while (*type != _C_UNION_E) { type = objc_skip_typespec (type); }
500 /* Just skip the following typespec */
502 return objc_skip_typespec (++type);
506 objc_error(nil, OBJC_ERR_BAD_TYPE, "%s: unknown type %s\n",
507 __PRETTY_FUNCTION__, type);
514 Skip an offset as part of a method encoding. This is prepended by a
515 '+' if the argument is passed in registers.
517 __inline__ const char*
518 objc_skip_offset (const char* type)
520 if (*type == '+') type++;
521 while(isdigit((int)*++type));
526 Skip an argument specification of a method encoding.
529 objc_skip_argspec (const char* type)
531 type = objc_skip_typespec (type);
532 type = objc_skip_offset (type);
537 Return the number of arguments that the method MTH expects.
538 Note that all methods need two implicit arguments `self' and
542 method_get_number_of_arguments (struct objc_method* mth)
545 const char* type = mth->method_types;
548 type = objc_skip_argspec (type);
555 Return the size of the argument block needed on the stack to invoke
556 the method MTH. This may be zero, if all arguments are passed in
561 method_get_sizeof_arguments (struct objc_method* mth)
563 const char* type = objc_skip_typespec (mth->method_types);
564 return objc_atoi (type);
568 Return a pointer to the next argument of ARGFRAME. type points to
569 the last argument. Typical use of this look like:
573 for (datum = method_get_first_argument (method, argframe, &type);
574 datum; datum = method_get_next_argument (argframe, &type))
576 unsigned flags = objc_get_type_qualifiers (type);
577 type = objc_skip_type_qualifiers (type);
579 [portal encodeData: datum ofType: type];
582 if ((flags & _F_IN) == _F_IN)
583 [portal encodeData: *(char**)datum ofType: ++type];
590 method_get_next_argument (arglist_t argframe,
593 const char *t = objc_skip_argspec (*type);
599 t = objc_skip_typespec (t);
602 return argframe->arg_regs + objc_atoi (++t);
604 return argframe->arg_ptr + objc_atoi (t);
608 Return a pointer to the value of the first argument of the method
609 described in M with the given argumentframe ARGFRAME. The type
610 is returned in TYPE. type must be passed to successive calls of
611 method_get_next_argument.
614 method_get_first_argument (struct objc_method* m,
618 *type = m->method_types;
619 return method_get_next_argument (argframe, type);
623 Return a pointer to the ARGth argument of the method
624 M from the frame ARGFRAME. The type of the argument
625 is returned in the value-result argument TYPE
629 method_get_nth_argument (struct objc_method* m,
630 arglist_t argframe, int arg,
633 const char* t = objc_skip_argspec (m->method_types);
635 if (arg > method_get_number_of_arguments (m))
639 t = objc_skip_argspec (t);
642 t = objc_skip_typespec (t);
645 return argframe->arg_regs + objc_atoi (++t);
647 return argframe->arg_ptr + objc_atoi (t);
650 unsigned objc_get_type_qualifiers (const char* type) {
657 case _C_CONST: res |= _F_CONST; break;
658 case _C_IN: res |= _F_IN; break;
659 case _C_INOUT: res |= _F_INOUT; break;
660 case _C_OUT: res |= _F_OUT; break;
661 case _C_BYCOPY: res |= _F_BYCOPY; break;
662 case _C_BYREF: res |= _F_BYREF; break;
663 case _C_ONEWAY: res |= _F_ONEWAY; break;
664 case _C_GCINVISIBLE: res |= _F_GCINVISIBLE; break;
672 /* The following three functions can be used to determine how a
673 structure is laid out by the compiler. For example:
675 struct objc_struct_layout layout;
678 objc_layout_structure (type, &layout);
679 while (objc_layout_structure_next_member (&layout))
684 objc_layout_structure_get_info (&layout, &position, &align, &type);
685 printf ("element %d has offset %d, alignment %d\n",
686 i++, position, align);
689 These functions are used by objc_sizeof_type and objc_alignof_type
690 functions to compute the size and alignment of structures. The
691 previous method of computing the size and alignment of a structure
692 was not working on some architectures, particulary on AIX, and in
693 the presence of bitfields inside the structure. */
695 objc_layout_structure (const char *type,
696 struct objc_struct_layout *layout)
700 if (*type++ != _C_STRUCT_B)
702 objc_error(nil, OBJC_ERR_BAD_TYPE,
703 "record type expected in objc_layout_structure, got %s\n",
707 layout->original_type = type;
709 /* Skip "<name>=" if any. Avoid embedded structures and unions. */
711 while (*ntype != _C_STRUCT_E && *ntype != _C_STRUCT_B && *ntype != _C_UNION_B
715 /* If there's a "<name>=", ntype - 1 points to '='; skip the the name */
716 if (*(ntype - 1) == '=')
720 layout->prev_type = NULL;
721 layout->record_size = 0;
722 layout->record_align = BITS_PER_UNIT;
724 #ifdef STRUCTURE_SIZE_BOUNDARY
725 layout->record_align = MAX (layout->record_align, STRUCTURE_SIZE_BOUNDARY);
731 objc_layout_structure_next_member (struct objc_struct_layout *layout)
733 /* unused: register int known_align = layout->record_size; */
734 register int desired_align = 0;
736 /* The following are used only if the field is a bitfield */
737 register const char *bfld_type = NULL;
738 register int bfld_type_size = 0;
739 register int bfld_type_align = 0;
740 register int bfld_field_size = 0;
742 /* The current type without the type qualifiers */
746 if (layout->prev_type == NULL)
748 layout->prev_type = layout->type;
749 layout->type = objc_skip_typespec (layout->prev_type);
754 /* Add the size of the previous field to the size of the record. */
755 if (layout->prev_type)
757 type = objc_skip_type_qualifiers (layout->prev_type);
759 if (*type != _C_BFLD)
760 layout->record_size += objc_sizeof_type (type) * BITS_PER_UNIT;
763 /* Get the bitfield's type */
764 for (bfld_type = type + 1;
765 isdigit((int)*bfld_type);
769 bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT;
770 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
771 bfld_field_size = objc_atoi (objc_skip_typespec (bfld_type));
772 layout->record_size += bfld_field_size;
776 if (*layout->type == _C_STRUCT_E)
779 /* Skip the variable name if any */
780 if (*layout->type == '"')
782 for (layout->type++; *layout->type++ != '"';)
786 type = objc_skip_type_qualifiers (layout->type);
788 if (*type != _C_BFLD)
789 desired_align = objc_alignof_type(type) * BITS_PER_UNIT;
793 /* Skip the bitfield's offset */
794 for (bfld_type = type + 1; isdigit((int)*bfld_type); bfld_type++)
797 bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT;
798 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
799 bfld_field_size = objc_atoi (objc_skip_typespec (bfld_type));
802 #ifdef BIGGEST_FIELD_ALIGNMENT
803 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
805 #ifdef ADJUST_FIELD_ALIGN
806 desired_align = ADJUST_FIELD_ALIGN (type, desired_align);
809 /* Record must have at least as much alignment as any field.
810 Otherwise, the alignment of the field within the record
812 #ifndef PCC_BITFIELD_TYPE_MATTERS
813 layout->record_align = MAX (layout->record_align, desired_align);
815 if (*type == _C_BFLD)
817 /* For these machines, a zero-length field does not
818 affect the alignment of the structure as a whole.
819 It does, however, affect the alignment of the next field
820 within the structure. */
822 layout->record_align = MAX (layout->record_align, desired_align);
824 desired_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
826 /* A named bit field of declared type `int'
827 forces the entire structure to have `int' alignment.
828 Q1: How is encoded this thing and how to check for it?
829 Q2: How to determine maximum_field_alignment at runtime? */
831 /* if (DECL_NAME (field) != 0) */
833 int type_align = bfld_type_align;
835 if (maximum_field_alignment != 0)
836 type_align = MIN (type_align, maximum_field_alignment);
837 else if (DECL_PACKED (field))
838 type_align = MIN (type_align, BITS_PER_UNIT);
841 layout->record_align = MAX (layout->record_align, type_align);
845 layout->record_align = MAX (layout->record_align, desired_align);
848 /* Does this field automatically have alignment it needs
849 by virtue of the fields that precede it and the record's
852 if (*type == _C_BFLD)
853 layout->record_size = objc_atoi (type + 1);
854 else if (layout->record_size % desired_align != 0)
856 /* No, we need to skip space before this field.
857 Bump the cumulative size to multiple of field alignment. */
858 layout->record_size = ROUND (layout->record_size, desired_align);
861 /* Jump to the next field in record. */
863 layout->prev_type = layout->type;
864 layout->type = objc_skip_typespec (layout->type); /* skip component */
870 void objc_layout_finish_structure (struct objc_struct_layout *layout,
874 if (layout->type && *layout->type == _C_STRUCT_E)
876 /* Work out the alignment of the record as one expression and store
877 in the record type. Round it up to a multiple of the record's
880 #ifdef ROUND_TYPE_ALIGN
881 layout->record_align = ROUND_TYPE_ALIGN (layout->original_type,
883 layout->record_align);
885 layout->record_align = MAX (1, layout->record_align);
888 #ifdef ROUND_TYPE_SIZE
889 layout->record_size = ROUND_TYPE_SIZE (layout->original_type,
891 layout->record_align);
893 /* Round the size up to be a multiple of the required alignment */
894 layout->record_size = ROUND (layout->record_size, layout->record_align);
900 *size = layout->record_size / BITS_PER_UNIT;
902 *align = layout->record_align / BITS_PER_UNIT;
906 void objc_layout_structure_get_info (struct objc_struct_layout *layout,
907 unsigned int *offset,
912 *offset = layout->record_size / BITS_PER_UNIT;
914 *align = layout->record_align / BITS_PER_UNIT;
916 *type = layout->prev_type;