460 lines
12 KiB
C
460 lines
12 KiB
C
/* Basic data types for Objective C.
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Copyright (C) 1998, 2002 Free Software Foundation, Inc.
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Contributed by Ovidiu Predescu.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* As a special exception, if you link this library with files
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compiled with GCC to produce an executable, this does not cause
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the resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why
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the executable file might be covered by the GNU General Public License. */
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#include "tconfig.h"
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#include "objc.h"
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#include "encoding.h"
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#include <assert.h>
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#include <string.h>
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#if OBJC_WITH_GC
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#include <gc.h>
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/* gc_typed.h uses the following but doesn't declare them */
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typedef GC_word word;
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typedef GC_signed_word signed_word;
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#if BITS_PER_WORD == 32
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# define LOGWL 5
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# define modWORDSZ(n) ((n) & 0x1f) /* n mod size of word */
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#endif
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#if BITS_PER_WORD == 64
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# define LOGWL 6
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# define modWORDSZ(n) ((n) & 0x3f) /* n mod size of word */
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#endif
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#define divWORDSZ(n) ((n) >> LOGWL) /* divide n by size of word */
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#include <gc_typed.h>
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/* The following functions set up in `mask` the corresponding pointers.
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The offset is incremented with the size of the type. */
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#define ROUND(V, A) \
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({ typeof (V) __v = (V); typeof (A) __a = (A); \
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__a * ((__v+__a - 1)/__a); })
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#define SET_BIT_FOR_OFFSET(mask, offset) \
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GC_set_bit (mask, offset / sizeof (void *))
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/* Some prototypes */
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static void
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__objc_gc_setup_struct (GC_bitmap mask, const char *type, int offset);
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static void
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__objc_gc_setup_union (GC_bitmap mask, const char *type, int offset);
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static void
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__objc_gc_setup_array (GC_bitmap mask, const char *type, int offset)
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{
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int i, len = atoi (type + 1);
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while (isdigit (*++type))
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/* do nothing */; /* skip the size of the array */
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switch (*type) {
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case _C_ARY_B:
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for (i = 0; i < len; i++)
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__objc_gc_setup_array (mask, type, offset);
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break;
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case _C_STRUCT_B:
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for (i = 0; i < len; i++)
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__objc_gc_setup_struct (mask, type, offset);
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break;
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case _C_UNION_B:
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for (i = 0; i < len; i++)
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__objc_gc_setup_union (mask, type, offset);
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break;
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default:
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break;
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}
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}
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static void
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__objc_gc_setup_struct (GC_bitmap mask, const char *type, int offset)
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{
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struct objc_struct_layout layout;
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unsigned int position;
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const char *mtype;
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objc_layout_structure (type, &layout);
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while (objc_layout_structure_next_member (&layout))
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{
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BOOL gc_invisible = NO;
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objc_layout_structure_get_info (&layout, &position, NULL, &mtype);
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/* Skip the variable name */
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if (*mtype == '"')
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{
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for (mtype++; *mtype++ != '"';)
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/* do nothing */;
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}
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if (*mtype == _C_GCINVISIBLE)
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{
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gc_invisible = YES;
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mtype++;
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}
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/* Add to position the offset of this structure */
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position += offset;
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switch (*mtype) {
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case _C_ID:
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case _C_CLASS:
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case _C_SEL:
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case _C_PTR:
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case _C_CHARPTR:
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case _C_ATOM:
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if (! gc_invisible)
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SET_BIT_FOR_OFFSET (mask, position);
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break;
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case _C_ARY_B:
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__objc_gc_setup_array (mask, mtype, position);
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break;
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case _C_STRUCT_B:
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__objc_gc_setup_struct (mask, mtype, position);
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break;
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case _C_UNION_B:
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__objc_gc_setup_union (mask, mtype, position);
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break;
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default:
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break;
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}
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}
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}
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static void
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__objc_gc_setup_union (GC_bitmap mask, const char *type, int offset)
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{
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/* Sub-optimal, quick implementation: assume the union is made of
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pointers, set up the mask accordingly. */
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int i, size, align;
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/* Skip the variable name */
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if (*type == '"')
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{
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for (type++; *type++ != '"';)
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/* do nothing */;
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}
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size = objc_sizeof_type (type);
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align = objc_alignof_type (type);
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offset = ROUND (offset, align);
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for (i = 0; i < size; i += sizeof (void *))
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{
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SET_BIT_FOR_OFFSET (mask, offset);
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offset += sizeof (void *);
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}
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}
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/* Iterates over the types in the structure that represents the class
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encoding and sets the bits in mask according to each ivar type. */
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static void
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__objc_gc_type_description_from_type (GC_bitmap mask, const char *type)
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{
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struct objc_struct_layout layout;
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unsigned int offset, align;
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const char *ivar_type;
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objc_layout_structure (type, &layout);
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while (objc_layout_structure_next_member (&layout))
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{
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BOOL gc_invisible = NO;
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objc_layout_structure_get_info (&layout, &offset, &align, &ivar_type);
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/* Skip the variable name */
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if (*ivar_type == '"')
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{
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for (ivar_type++; *ivar_type++ != '"';)
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/* do nothing */;
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}
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if (*ivar_type == _C_GCINVISIBLE)
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{
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gc_invisible = YES;
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ivar_type++;
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}
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switch (*ivar_type) {
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case _C_ID:
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case _C_CLASS:
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case _C_SEL:
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case _C_PTR:
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case _C_CHARPTR:
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if (! gc_invisible)
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SET_BIT_FOR_OFFSET (mask, offset);
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break;
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case _C_ARY_B:
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__objc_gc_setup_array (mask, ivar_type, offset);
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break;
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case _C_STRUCT_B:
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__objc_gc_setup_struct (mask, ivar_type, offset);
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break;
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case _C_UNION_B:
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__objc_gc_setup_union (mask, ivar_type, offset);
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break;
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default:
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break;
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}
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}
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}
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/* Computes in *type the full type encoding of this class including
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its super classes. '*size' gives the total number of bytes allocated
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into *type, '*current' the number of bytes used so far by the
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encoding. */
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static void
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__objc_class_structure_encoding (Class class, char **type, int *size,
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int *current)
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{
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int i, ivar_count;
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struct objc_ivar_list *ivars;
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if (! class)
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{
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strcat (*type, "{");
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*current++;
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return;
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}
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/* Add the type encodings of the super classes */
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__objc_class_structure_encoding (class->super_class, type, size, current);
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ivars = class->ivars;
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if (! ivars)
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return;
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ivar_count = ivars->ivar_count;
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for (i = 0; i < ivar_count; i++)
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{
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struct objc_ivar *ivar = &(ivars->ivar_list[i]);
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const char *ivar_type = ivar->ivar_type;
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int len = strlen (ivar_type);
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if (*current + len + 1 >= *size)
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{
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/* Increase the size of the encoding string so that it
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contains this ivar's type. */
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*size = ROUND (*current + len + 1, 10);
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*type = objc_realloc (*type, *size);
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}
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strcat (*type + *current, ivar_type);
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*current += len;
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}
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}
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/* Allocates the memory that will hold the type description for class
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and calls the __objc_class_structure_encoding that generates this
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value. */
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void
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__objc_generate_gc_type_description (Class class)
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{
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GC_bitmap mask;
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int bits_no, size;
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int type_size = 10, current;
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char *class_structure_type;
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if (! CLS_ISCLASS (class))
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return;
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/* We have to create a mask in which each bit counts for a pointer member.
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We take into consideration all the non-pointer instance variables and we
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round them up to the alignment. */
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/* The number of bits in the mask is the size of an instance in bytes divided
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by the size of a pointer. */
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bits_no = (ROUND (class_get_instance_size (class), sizeof (void *))
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/ sizeof (void *));
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size = ROUND (bits_no, BITS_PER_WORD) / BITS_PER_WORD;
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mask = objc_atomic_malloc (size * sizeof (int));
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memset (mask, 0, size * sizeof (int));
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class_structure_type = objc_atomic_malloc (type_size);
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*class_structure_type = current = 0;
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__objc_class_structure_encoding (class, &class_structure_type,
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&type_size, ¤t);
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if (current + 1 == type_size)
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class_structure_type = objc_realloc (class_structure_type, ++type_size);
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strcat (class_structure_type + current, "}");
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#ifdef DEBUG
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printf ("type description for '%s' is %s\n", class->name, class_structure_type);
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#endif
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__objc_gc_type_description_from_type (mask, class_structure_type);
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objc_free (class_structure_type);
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#ifdef DEBUG
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printf (" mask for '%s', type '%s' (bits %d, mask size %d) is:",
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class_structure_type, class->name, bits_no, size);
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{
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int i;
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for (i = 0; i < size; i++)
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printf (" %lx", mask[i]);
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}
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puts ("");
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#endif
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class->gc_object_type = (void *) GC_make_descriptor (mask, bits_no);
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}
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/* Returns YES if type denotes a pointer type, NO otherwise */
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static inline BOOL
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__objc_ivar_pointer (const char *type)
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{
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type = objc_skip_type_qualifiers (type);
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return (*type == _C_ID
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|| *type == _C_CLASS
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|| *type == _C_SEL
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|| *type == _C_PTR
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|| *type == _C_CHARPTR
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|| *type == _C_ATOM);
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}
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/* Mark the instance variable whose name is given by ivarname as a
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weak pointer (a pointer hidden to the garbage collector) if
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gc_invisible is true. If gc_invisible is false it unmarks the
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instance variable and makes it a normal pointer, visible to the
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garbage collector.
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This operation only makes sense on instance variables that are
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pointers. */
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void
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class_ivar_set_gcinvisible (Class class, const char *ivarname,
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BOOL gc_invisible)
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{
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int i, ivar_count;
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struct objc_ivar_list *ivars;
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if (! class || ! ivarname)
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return;
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ivars = class->ivars;
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if (! ivars)
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return;
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ivar_count = ivars->ivar_count;
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for (i = 0; i < ivar_count; i++)
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{
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struct objc_ivar *ivar = &(ivars->ivar_list[i]);
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const char *type;
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if (! ivar->ivar_name || strcmp (ivar->ivar_name, ivarname))
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continue;
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assert (ivar->ivar_type);
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type = ivar->ivar_type;
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/* Skip the variable name */
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if (*type == '"')
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{
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for (type++; *type++ != '"';)
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/* do nothing */;
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}
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if (*type == _C_GCINVISIBLE)
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{
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char *new_type;
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if (gc_invisible || ! __objc_ivar_pointer (type))
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return; /* The type of the variable already matches the
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requested gc_invisible type */
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/* The variable is gc_invisible and we have to reverse it */
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new_type = objc_atomic_malloc (strlen (ivar->ivar_type));
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strncpy (new_type, ivar->ivar_type,
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(size_t)(type - ivar->ivar_type));
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strcat (new_type, type + 1);
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ivar->ivar_type = new_type;
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}
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else
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{
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char *new_type;
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if (! gc_invisible || ! __objc_ivar_pointer (type))
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return; /* The type of the variable already matches the
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requested gc_invisible type */
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/* The variable is gc visible and we have to make it gc_invisible */
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new_type = objc_malloc (strlen (ivar->ivar_type) + 2);
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strncpy (new_type, ivar->ivar_type,
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(size_t)(type - ivar->ivar_type));
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strcat (new_type, "!");
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strcat (new_type, type);
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ivar->ivar_type = new_type;
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}
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__objc_generate_gc_type_description (class);
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return;
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}
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/* Search the instance variable in the superclasses */
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class_ivar_set_gcinvisible (class->super_class, ivarname, gc_invisible);
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}
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#else /* !OBJC_WITH_GC */
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void
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__objc_generate_gc_type_description (Class class __attribute__ ((__unused__)))
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{
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}
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void class_ivar_set_gcinvisible (Class class __attribute__ ((__unused__)),
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const char *ivarname __attribute__ ((__unused__)),
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BOOL gc_invisible __attribute__ ((__unused__)))
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{
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}
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#endif /* OBJC_WITH_GC */
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