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. */
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) objc_skip_typespec(TYPE)
67 atoi (const char* str)
71 while (isdigit (*str))
72 res *= 10, res += (*str++ - '0');
78 return the size of an object specified by type
82 objc_sizeof_type (const char* type)
84 /* Skip the variable name if any */
87 for (type++; *type++ != '"';)
109 return sizeof(unsigned char);
113 return sizeof(short);
117 return sizeof(unsigned short);
125 return sizeof(unsigned int);
133 return sizeof(unsigned long);
137 return sizeof(long long);
141 return sizeof(unsigned long long);
145 return sizeof(float);
149 return sizeof(double);
158 return sizeof(char*);
163 int len = atoi(type+1);
164 while (isdigit(*++type));
165 return len*objc_aligned_size (type);
171 /* The new encoding of bitfields is: b 'position' 'type' 'size' */
173 int startByte, endByte;
175 position = atoi (type + 1);
176 while (isdigit (*++type));
177 size = atoi (type + 1);
179 startByte = position / BITS_PER_UNIT;
180 endByte = (position + size) / BITS_PER_UNIT;
181 return endByte - startByte;
186 struct objc_struct_layout layout;
189 objc_layout_structure (type, &layout);
190 while (objc_layout_structure_next_member (&layout))
192 objc_layout_finish_structure (&layout, &size, NULL);
200 while (*type != _C_UNION_E && *type++ != '=') /* do nothing */;
201 while (*type != _C_UNION_E)
203 /* Skip the variable name if any */
206 for (type++; *type++ != '"';)
209 max_size = MAX (max_size, objc_sizeof_type (type));
210 type = objc_skip_typespec (type);
217 objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
225 Return the alignment of an object specified by type
229 objc_alignof_type(const char* type)
231 /* Skip the variable name if any */
234 for (type++; *type++ != '"';)
239 return __alignof__(id);
243 return __alignof__(Class);
247 return __alignof__(SEL);
251 return __alignof__(char);
255 return __alignof__(unsigned char);
259 return __alignof__(short);
263 return __alignof__(unsigned short);
267 return __alignof__(int);
271 return __alignof__(unsigned int);
275 return __alignof__(long);
279 return __alignof__(unsigned long);
283 return __alignof__(long long);
287 return __alignof__(unsigned long long);
291 return __alignof__(float);
295 return __alignof__(double);
301 return __alignof__(char*);
305 while (isdigit(*++type)) /* do nothing */;
306 return objc_alignof_type (type);
310 struct objc_struct_layout layout;
313 objc_layout_structure (type, &layout);
314 while (objc_layout_structure_next_member (&layout))
316 objc_layout_finish_structure (&layout, NULL, &align);
324 while (*type != _C_UNION_E && *type++ != '=') /* do nothing */;
325 while (*type != _C_UNION_E)
327 /* Skip the variable name if any */
330 for (type++; *type++ != '"';)
333 maxalign = MAX (maxalign, objc_alignof_type (type));
334 type = objc_skip_typespec (type);
341 objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
348 The aligned size if the size rounded up to the nearest alignment.
352 objc_aligned_size (const char* type)
356 /* Skip the variable name */
359 for (type++; *type++ != '"';)
363 size = objc_sizeof_type (type);
364 align = objc_alignof_type (type);
366 return ROUND (size, align);
370 The size rounded up to the nearest integral of the wordsize, taken
371 to be the size of a void*.
375 objc_promoted_size (const char* type)
379 /* Skip the variable name */
382 for (type++; *type++ != '"';)
386 size = objc_sizeof_type (type);
387 wordsize = sizeof (void*);
389 return ROUND (size, wordsize);
393 Skip type qualifiers. These may eventually precede typespecs
394 occurring in method prototype encodings.
398 objc_skip_type_qualifiers (const char* type)
400 while (*type == _C_CONST
404 || *type == _C_BYCOPY
405 || *type == _C_ONEWAY
406 || *type == _C_GCINVISIBLE)
415 Skip one typespec element. If the typespec is prepended by type
416 qualifiers, these are skipped as well.
420 objc_skip_typespec (const char* type)
422 /* Skip the variable name if any */
425 for (type++; *type++ != '"';)
429 type = objc_skip_type_qualifiers (type);
434 /* An id may be annotated by the actual type if it is known
435 with the @"ClassName" syntax */
441 while (*++type != '"') /* do nothing */;
445 /* The following are one character type codes */
468 /* skip digits, typespec and closing ']' */
470 while(isdigit(*++type));
471 type = objc_skip_typespec(type);
472 if (*type == _C_ARY_E)
476 objc_error(nil, OBJC_ERR_BAD_TYPE, "bad array type %s\n", type);
481 /* The new encoding of bitfields is: b 'position' 'type' 'size' */
482 while (isdigit (*++type)); /* skip position */
483 while (isdigit (*++type)); /* skip type and size */
487 /* skip name, and elements until closing '}' */
489 while (*type != _C_STRUCT_E && *type++ != '=');
490 while (*type != _C_STRUCT_E) { type = objc_skip_typespec (type); }
494 /* skip name, and elements until closing ')' */
496 while (*type != _C_UNION_E && *type++ != '=');
497 while (*type != _C_UNION_E) { type = objc_skip_typespec (type); }
501 /* Just skip the following typespec */
503 return objc_skip_typespec (++type);
507 objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
514 Skip an offset as part of a method encoding. This is prepended by a
515 '+' if the argument is passed in registers.
518 objc_skip_offset (const char* type)
520 if (*type == '+') type++;
521 while(isdigit(*++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);
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 + atoi (++t);
604 return argframe->arg_ptr + 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 + atoi (++t);
647 return argframe->arg_ptr + atoi (t);
651 objc_get_type_qualifiers (const char* type)
659 case _C_CONST: res |= _F_CONST; break;
660 case _C_IN: res |= _F_IN; break;
661 case _C_INOUT: res |= _F_INOUT; break;
662 case _C_OUT: res |= _F_OUT; break;
663 case _C_BYCOPY: res |= _F_BYCOPY; break;
664 case _C_ONEWAY: res |= _F_ONEWAY; break;
665 case _C_GCINVISIBLE: res |= _F_GCINVISIBLE; break;
673 /* The following three functions can be used to determine how a
674 structure is laid out by the compiler. For example:
676 struct objc_struct_layout layout;
679 objc_layout_structure (type, &layout);
680 while (objc_layout_structure_next_member (&layout))
685 objc_layout_structure_get_info (&layout, &position, &align, &type);
686 printf ("element %d has offset %d, alignment %d\n",
687 i++, position, align);
690 These functions are used by objc_sizeof_type and objc_alignof_type
691 functions to compute the size and alignment of structures. The
692 previous method of computing the size and alignment of a structure
693 was not working on some architectures, particulary on AIX, and in
694 the presence of bitfields inside the structure. */
696 objc_layout_structure (const char *type,
697 struct objc_struct_layout *layout)
701 if (*type++ != _C_STRUCT_B)
703 objc_error(nil, OBJC_ERR_BAD_TYPE,
704 "record type expected in objc_layout_structure, got %s\n",
708 layout->original_type = type;
710 /* Skip "<name>=" if any. Avoid embedded structures and unions. */
712 while (*ntype != _C_STRUCT_E && *ntype != _C_STRUCT_B && *ntype != _C_UNION_B
716 /* If there's a "<name>=", ntype - 1 points to '='; skip the the name */
717 if (*(ntype - 1) == '=')
721 layout->prev_type = NULL;
722 layout->record_size = 0;
723 layout->record_align = BITS_PER_UNIT;
725 #ifdef STRUCTURE_SIZE_BOUNDARY
726 layout->record_align = MAX (layout->record_align, STRUCTURE_SIZE_BOUNDARY);
732 objc_layout_structure_next_member (struct objc_struct_layout *layout)
734 register int known_align = layout->record_size;
735 register int desired_align = 0;
737 /* The following are used only if the field is a bitfield */
738 register const char *bfld_type;
739 register int bfld_type_size, bfld_type_align, bfld_field_size;
741 /* The current type without the type qualifiers */
745 if (layout->prev_type == NULL)
747 layout->prev_type = layout->type;
748 layout->type = objc_skip_typespec (layout->prev_type);
753 /* Add the size of the previous field to the size of the record. */
754 if (layout->prev_type)
756 type = objc_skip_type_qualifiers (layout->prev_type);
758 if (*type != _C_BFLD)
759 layout->record_size += objc_sizeof_type (type) * BITS_PER_UNIT;
762 /* Get the bitfield's type */
763 for (bfld_type = type + 1;
768 bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT;
769 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
770 bfld_field_size = atoi (objc_skip_typespec (bfld_type));
771 layout->record_size += bfld_field_size;
775 if (*layout->type == _C_STRUCT_E)
778 /* Skip the variable name if any */
779 if (*layout->type == '"')
781 for (layout->type++; *layout->type++ != '"';)
785 type = objc_skip_type_qualifiers (layout->type);
787 if (*type != _C_BFLD)
788 desired_align = objc_alignof_type(type) * BITS_PER_UNIT;
792 /* Skip the bitfield's offset */
793 for (bfld_type = type + 1; isdigit(*bfld_type); bfld_type++)
796 bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT;
797 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
798 bfld_field_size = atoi (objc_skip_typespec (bfld_type));
801 #ifdef BIGGEST_FIELD_ALIGNMENT
802 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
804 #ifdef ADJUST_FIELD_ALIGN
805 desired_align = ADJUST_FIELD_ALIGN (type, desired_align);
808 /* Record must have at least as much alignment as any field.
809 Otherwise, the alignment of the field within the record
811 #ifndef PCC_BITFIELD_TYPE_MATTERS
812 layout->record_align = MAX (layout->record_align, desired_align);
814 if (*type == _C_BFLD)
816 /* For these machines, a zero-length field does not
817 affect the alignment of the structure as a whole.
818 It does, however, affect the alignment of the next field
819 within the structure. */
821 layout->record_align = MAX (layout->record_align, desired_align);
823 desired_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
825 /* A named bit field of declared type `int'
826 forces the entire structure to have `int' alignment.
827 Q1: How is encoded this thing and how to check for it?
828 Q2: How to determine maximum_field_alignment at runtime? */
830 /* if (DECL_NAME (field) != 0) */
832 int type_align = bfld_type_align;
834 if (maximum_field_alignment != 0)
835 type_align = MIN (type_align, maximum_field_alignment);
836 else if (DECL_PACKED (field))
837 type_align = MIN (type_align, BITS_PER_UNIT);
840 layout->record_align = MAX (layout->record_align, type_align);
844 layout->record_align = MAX (layout->record_align, desired_align);
847 /* Does this field automatically have alignment it needs
848 by virtue of the fields that precede it and the record's
851 if (*type == _C_BFLD)
852 layout->record_size = atoi (type + 1);
853 else if (layout->record_size % desired_align != 0)
855 /* No, we need to skip space before this field.
856 Bump the cumulative size to multiple of field alignment. */
857 layout->record_size = ROUND (layout->record_size, desired_align);
860 /* Jump to the next field in record. */
862 layout->prev_type = layout->type;
863 layout->type = objc_skip_typespec (layout->type); /* skip component */
869 void objc_layout_finish_structure (struct objc_struct_layout *layout,
873 if (layout->type && *layout->type == _C_STRUCT_E)
875 /* Work out the alignment of the record as one expression and store
876 in the record type. Round it up to a multiple of the record's
879 #ifdef ROUND_TYPE_ALIGN
880 layout->record_align = ROUND_TYPE_ALIGN (layout->original_type,
882 layout->record_align);
884 layout->record_align = MAX (1, layout->record_align);
887 #ifdef ROUND_TYPE_SIZE
888 layout->record_size = ROUND_TYPE_SIZE (layout->original_type,
890 layout->record_align);
892 /* Round the size up to be a multiple of the required alignment */
893 layout->record_size = ROUND (layout->record_size, layout->record_align);
899 *size = layout->record_size / BITS_PER_UNIT;
901 *align = layout->record_align / BITS_PER_UNIT;
905 void objc_layout_structure_get_info (struct objc_struct_layout *layout,
906 unsigned int *offset,
911 *offset = layout->record_size / BITS_PER_UNIT;
913 *align = layout->record_align / BITS_PER_UNIT;
915 *type = layout->prev_type;