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 RECORD_TYPE _C_STRUCT_B
51 #define UNION_TYPE _C_UNION_B
52 #define QUAL_UNION_TYPE _C_UNION_B
54 #define TYPE_FIELDS(TYPE) objc_skip_typespec (TYPE)
56 #define DECL_MODE(TYPE) *(TYPE)
63 atoi (const char* str)
67 while (isdigit (*str))
68 res *= 10, res += (*str++ - '0');
74 return the size of an object specified by type
78 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 = atoi(type+1);
160 while (isdigit(*++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 = atoi (type + 1);
172 while (isdigit (*++type));
173 size = 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, "unknown type %s\n", type);
221 Return the alignment of an object specified by type
225 objc_alignof_type(const char* type)
227 /* Skip the variable name if any */
230 for (type++; *type++ != '"';)
235 return __alignof__(id);
239 return __alignof__(Class);
243 return __alignof__(SEL);
247 return __alignof__(char);
251 return __alignof__(unsigned char);
255 return __alignof__(short);
259 return __alignof__(unsigned short);
263 return __alignof__(int);
267 return __alignof__(unsigned int);
271 return __alignof__(long);
275 return __alignof__(unsigned long);
279 return __alignof__(long long);
283 return __alignof__(unsigned long long);
287 return __alignof__(float);
291 return __alignof__(double);
297 return __alignof__(char*);
301 while (isdigit(*++type)) /* do nothing */;
302 return objc_alignof_type (type);
306 struct objc_struct_layout layout;
309 objc_layout_structure (type, &layout);
310 while (objc_layout_structure_next_member (&layout))
312 objc_layout_finish_structure (&layout, NULL, &align);
320 while (*type != _C_UNION_E && *type++ != '=') /* do nothing */;
321 while (*type != _C_UNION_E)
323 /* Skip the variable name if any */
326 for (type++; *type++ != '"';)
329 maxalign = MAX (maxalign, objc_alignof_type (type));
330 type = objc_skip_typespec (type);
337 objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
344 The aligned size if the size rounded up to the nearest alignment.
348 objc_aligned_size (const char* type)
352 /* Skip the variable name */
355 for (type++; *type++ != '"';)
359 size = objc_sizeof_type (type);
360 align = objc_alignof_type (type);
362 return ROUND (size, align);
366 The size rounded up to the nearest integral of the wordsize, taken
367 to be the size of a void*.
371 objc_promoted_size (const char* type)
375 /* Skip the variable name */
378 for (type++; *type++ != '"';)
382 size = objc_sizeof_type (type);
383 wordsize = sizeof (void*);
385 return ROUND (size, wordsize);
389 Skip type qualifiers. These may eventually precede typespecs
390 occurring in method prototype encodings.
394 objc_skip_type_qualifiers (const char* type)
396 while (*type == _C_CONST
400 || *type == _C_BYCOPY
401 || *type == _C_ONEWAY
402 || *type == _C_GCINVISIBLE)
411 Skip one typespec element. If the typespec is prepended by type
412 qualifiers, these are skipped as well.
416 objc_skip_typespec (const char* type)
418 /* Skip the variable name if any */
421 for (type++; *type++ != '"';)
425 type = objc_skip_type_qualifiers (type);
430 /* An id may be annotated by the actual type if it is known
431 with the @"ClassName" syntax */
437 while (*++type != '"') /* do nothing */;
441 /* The following are one character type codes */
464 /* skip digits, typespec and closing ']' */
466 while(isdigit(*++type));
467 type = objc_skip_typespec(type);
468 if (*type == _C_ARY_E)
472 objc_error(nil, OBJC_ERR_BAD_TYPE, "bad array type %s\n", type);
477 /* The new encoding of bitfields is: b 'position' 'type' 'size' */
478 while (isdigit (*++type)); /* skip position */
479 while (isdigit (*++type)); /* skip type and size */
483 /* skip name, and elements until closing '}' */
485 while (*type != _C_STRUCT_E && *type++ != '=');
486 while (*type != _C_STRUCT_E) { type = objc_skip_typespec (type); }
490 /* skip name, and elements until closing ')' */
492 while (*type != _C_UNION_E && *type++ != '=');
493 while (*type != _C_UNION_E) { type = objc_skip_typespec (type); }
497 /* Just skip the following typespec */
499 return objc_skip_typespec (++type);
503 objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type);
510 Skip an offset as part of a method encoding. This is prepended by a
511 '+' if the argument is passed in registers.
514 objc_skip_offset (const char* type)
516 if (*type == '+') type++;
517 while(isdigit(*++type));
522 Skip an argument specification of a method encoding.
525 objc_skip_argspec (const char* type)
527 type = objc_skip_typespec (type);
528 type = objc_skip_offset (type);
533 Return the number of arguments that the method MTH expects.
534 Note that all methods need two implicit arguments `self' and
538 method_get_number_of_arguments (struct objc_method* mth)
541 const char* type = mth->method_types;
544 type = objc_skip_argspec (type);
551 Return the size of the argument block needed on the stack to invoke
552 the method MTH. This may be zero, if all arguments are passed in
557 method_get_sizeof_arguments (struct objc_method* mth)
559 const char* type = objc_skip_typespec (mth->method_types);
564 Return a pointer to the next argument of ARGFRAME. type points to
565 the last argument. Typical use of this look like:
569 for (datum = method_get_first_argument (method, argframe, &type);
570 datum; datum = method_get_next_argument (argframe, &type))
572 unsigned flags = objc_get_type_qualifiers (type);
573 type = objc_skip_type_qualifiers (type);
575 [portal encodeData: datum ofType: type];
578 if ((flags & _F_IN) == _F_IN)
579 [portal encodeData: *(char**)datum ofType: ++type];
586 method_get_next_argument (arglist_t argframe,
589 const char *t = objc_skip_argspec (*type);
595 t = objc_skip_typespec (t);
598 return argframe->arg_regs + atoi (++t);
600 return argframe->arg_ptr + atoi (t);
604 Return a pointer to the value of the first argument of the method
605 described in M with the given argumentframe ARGFRAME. The type
606 is returned in TYPE. type must be passed to successive calls of
607 method_get_next_argument.
610 method_get_first_argument (struct objc_method* m,
614 *type = m->method_types;
615 return method_get_next_argument (argframe, type);
619 Return a pointer to the ARGth argument of the method
620 M from the frame ARGFRAME. The type of the argument
621 is returned in the value-result argument TYPE
625 method_get_nth_argument (struct objc_method* m,
626 arglist_t argframe, int arg,
629 const char* t = objc_skip_argspec (m->method_types);
631 if (arg > method_get_number_of_arguments (m))
635 t = objc_skip_argspec (t);
638 t = objc_skip_typespec (t);
641 return argframe->arg_regs + atoi (++t);
643 return argframe->arg_ptr + atoi (t);
647 objc_get_type_qualifiers (const char* type)
655 case _C_CONST: res |= _F_CONST; break;
656 case _C_IN: res |= _F_IN; break;
657 case _C_INOUT: res |= _F_INOUT; break;
658 case _C_OUT: res |= _F_OUT; break;
659 case _C_BYCOPY: res |= _F_BYCOPY; break;
660 case _C_ONEWAY: res |= _F_ONEWAY; break;
661 case _C_GCINVISIBLE: res |= _F_GCINVISIBLE; break;
669 /* The following three functions can be used to determine how a
670 structure is laid out by the compiler. For example:
672 struct objc_struct_layout layout;
675 objc_layout_structure (type, &layout);
676 while (objc_layout_structure_next_member (&layout))
681 objc_layout_structure_get_info (&layout, &position, &align, &type);
682 printf ("element %d has offset %d, alignment %d\n",
683 i++, position, align);
686 These functions are used by objc_sizeof_type and objc_alignof_type
687 functions to compute the size and alignment of structures. The
688 previous method of computing the size and alignment of a structure
689 was not working on some architectures, particulary on AIX, and in
690 the presence of bitfields inside the structure. */
692 objc_layout_structure (const char *type,
693 struct objc_struct_layout *layout)
697 if (*type++ != _C_STRUCT_B)
699 objc_error(nil, OBJC_ERR_BAD_TYPE,
700 "record type expected in objc_layout_structure, got %s\n",
704 layout->original_type = type;
706 /* Skip "<name>=" if any. Avoid embedded structures and unions. */
708 while (*ntype != _C_STRUCT_E && *ntype != _C_STRUCT_B && *ntype != _C_UNION_B
712 /* If there's a "<name>=", ntype - 1 points to '='; skip the the name */
713 if (*(ntype - 1) == '=')
717 layout->prev_type = NULL;
718 layout->record_size = 0;
719 layout->record_align = BITS_PER_UNIT;
721 #ifdef STRUCTURE_SIZE_BOUNDARY
722 layout->record_align = MAX (layout->record_align, STRUCTURE_SIZE_BOUNDARY);
728 objc_layout_structure_next_member (struct objc_struct_layout *layout)
730 register int known_align = layout->record_size;
731 register int desired_align = 0;
733 /* The following are used only if the field is a bitfield */
734 register const char *bfld_type;
735 register int bfld_type_size, bfld_type_align, bfld_field_size;
737 /* The current type without the type qualifiers */
741 if (layout->prev_type == NULL)
743 layout->prev_type = layout->type;
744 layout->type = objc_skip_typespec (layout->prev_type);
749 /* Add the size of the previous field to the size of the record. */
750 if (layout->prev_type)
752 type = objc_skip_type_qualifiers (layout->prev_type);
754 if (*type != _C_BFLD)
755 layout->record_size += objc_sizeof_type (type) * BITS_PER_UNIT;
758 /* Get the bitfield's type */
759 for (bfld_type = type + 1;
764 bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT;
765 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
766 bfld_field_size = atoi (objc_skip_typespec (bfld_type));
767 layout->record_size += bfld_field_size;
771 if (*layout->type == _C_STRUCT_E)
774 /* Skip the variable name if any */
775 if (*layout->type == '"')
777 for (layout->type++; *layout->type++ != '"';)
781 type = objc_skip_type_qualifiers (layout->type);
783 if (*type != _C_BFLD)
784 desired_align = objc_alignof_type(type) * BITS_PER_UNIT;
788 /* Skip the bitfield's offset */
789 for (bfld_type = type + 1; isdigit(*bfld_type); bfld_type++)
792 bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT;
793 bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
794 bfld_field_size = atoi (objc_skip_typespec (bfld_type));
797 #ifdef BIGGEST_FIELD_ALIGNMENT
798 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
800 #ifdef ADJUST_FIELD_ALIGN
801 desired_align = ADJUST_FIELD_ALIGN (type, desired_align);
804 /* Record must have at least as much alignment as any field.
805 Otherwise, the alignment of the field within the record
807 #ifndef PCC_BITFIELD_TYPE_MATTERS
808 layout->record_align = MAX (layout->record_align, desired_align);
810 if (*type == _C_BFLD)
812 /* For these machines, a zero-length field does not
813 affect the alignment of the structure as a whole.
814 It does, however, affect the alignment of the next field
815 within the structure. */
817 layout->record_align = MAX (layout->record_align, desired_align);
819 desired_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT;
821 /* A named bit field of declared type `int'
822 forces the entire structure to have `int' alignment.
823 Q1: How is encoded this thing and how to check for it?
824 Q2: How to determine maximum_field_alignment at runtime? */
826 /* if (DECL_NAME (field) != 0) */
828 int type_align = bfld_type_align;
830 if (maximum_field_alignment != 0)
831 type_align = MIN (type_align, maximum_field_alignment);
832 else if (DECL_PACKED (field))
833 type_align = MIN (type_align, BITS_PER_UNIT);
836 layout->record_align = MAX (layout->record_align, type_align);
840 layout->record_align = MAX (layout->record_align, desired_align);
843 /* Does this field automatically have alignment it needs
844 by virtue of the fields that precede it and the record's
847 if (*type == _C_BFLD)
848 layout->record_size = atoi (type + 1);
849 else if (layout->record_size % desired_align != 0)
851 /* No, we need to skip space before this field.
852 Bump the cumulative size to multiple of field alignment. */
853 layout->record_size = ROUND (layout->record_size, desired_align);
856 /* Jump to the next field in record. */
858 layout->prev_type = layout->type;
859 layout->type = objc_skip_typespec (layout->type); /* skip component */
865 void objc_layout_finish_structure (struct objc_struct_layout *layout,
869 if (layout->type && *layout->type == _C_STRUCT_E)
871 /* Work out the alignment of the record as one expression and store
872 in the record type. Round it up to a multiple of the record's
875 #ifdef ROUND_TYPE_ALIGN
876 layout->record_align = ROUND_TYPE_ALIGN (layout->original_type,
878 layout->record_align);
880 layout->record_align = MAX (1, layout->record_align);
883 #ifdef ROUND_TYPE_SIZE
884 layout->record_size = ROUND_TYPE_SIZE (layout->original_type,
886 layout->record_align);
888 /* Round the size up to be a multiple of the required alignment */
889 layout->record_size = ROUND (layout->record_size, layout->record_align);
895 *size = layout->record_size / BITS_PER_UNIT;
897 *align = layout->record_align / BITS_PER_UNIT;
901 void objc_layout_structure_get_info (struct objc_struct_layout *layout,
902 unsigned int *offset,
907 *offset = layout->record_size / BITS_PER_UNIT;
909 *align = layout->record_align / BITS_PER_UNIT;
911 *type = layout->prev_type;