diff options
author | bje <bje@138bc75d-0d04-0410-961f-82ee72b054a4> | 1998-09-21 01:22:07 +0000 |
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committer | bje <bje@138bc75d-0d04-0410-961f-82ee72b054a4> | 1998-09-21 01:22:07 +0000 |
commit | 8a7d0ecc89848fa1b5bd4af83609f07ee93d11e3 (patch) | |
tree | 74295f11944f5c930aca90bb544749afb89e227c /libobjc/encoding.c | |
parent | 6f52bf52570132d0a271a1c5b3990e051e6c5be3 (diff) | |
download | gcc-8a7d0ecc89848fa1b5bd4af83609f07ee93d11e3.tar.gz |
1998-09-21 Ben Elliston <bje@cygnus.com>
* New directory. Moved files from ../gcc/objc.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@22514 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'libobjc/encoding.c')
-rw-r--r-- | libobjc/encoding.c | 912 |
1 files changed, 912 insertions, 0 deletions
diff --git a/libobjc/encoding.c b/libobjc/encoding.c new file mode 100644 index 00000000000..ab47e9c4bf4 --- /dev/null +++ b/libobjc/encoding.c @@ -0,0 +1,912 @@ +/* Encoding of types for Objective C. + Copyright (C) 1993, 1995, 1996, 1997, 1998 Free Software Foundation, Inc. + Contributed by Kresten Krab Thorup + Bitfield support by Ovidiu Predescu + +This file is part of GNU CC. + +GNU CC is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU CC is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU CC; see the file COPYING. If not, write to +the Free Software Foundation, 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA. */ + +/* As a special exception, if you link this library with files + compiled with GCC to produce an executable, this does not cause + the resulting executable to be covered by the GNU General Public License. + This exception does not however invalidate any other reasons why + the executable file might be covered by the GNU General Public License. */ + +#include "tconfig.h" +#include "objc-api.h" +#include "encoding.h" + +#define MAX(X, Y) \ + ({ typeof(X) __x = (X), __y = (Y); \ + (__x > __y ? __x : __y); }) + +#define MIN(X, Y) \ + ({ typeof(X) __x = (X), __y = (Y); \ + (__x < __y ? __x : __y); }) + +#define ROUND(V, A) \ + ({ typeof(V) __v=(V); typeof(A) __a=(A); \ + __a*((__v+__a-1)/__a); }) + + +/* Various hacks for objc_layout_record. These are used by the target + macros. */ + +#define TREE_CODE(TYPE) *TYPE +#define RECORD_TYPE _C_STRUCT_B +#define UNION_TYPE _C_UNION_B +#define QUAL_UNION_TYPE _C_UNION_B + +#define TYPE_FIELDS(TYPE) objc_skip_typespec (TYPE) + +#define DECL_MODE(TYPE) *(TYPE) + +#define DFmode _C_DBL + + + +static inline int +atoi (const char* str) +{ + int res = 0; + + while (isdigit (*str)) + res *= 10, res += (*str++ - '0'); + + return res; +} + +/* + return the size of an object specified by type +*/ + +int +objc_sizeof_type (const char* type) +{ + /* Skip the variable name if any */ + if (*type == '"') + { + for (type++; *type++ != '"';) + /* do nothing */; + } + + switch(*type) { + case _C_ID: + return sizeof(id); + break; + + case _C_CLASS: + return sizeof(Class); + break; + + case _C_SEL: + return sizeof(SEL); + break; + + case _C_CHR: + return sizeof(char); + break; + + case _C_UCHR: + return sizeof(unsigned char); + break; + + case _C_SHT: + return sizeof(short); + break; + + case _C_USHT: + return sizeof(unsigned short); + break; + + case _C_INT: + return sizeof(int); + break; + + case _C_UINT: + return sizeof(unsigned int); + break; + + case _C_LNG: + return sizeof(long); + break; + + case _C_ULNG: + return sizeof(unsigned long); + break; + + case _C_LNG_LNG: + return sizeof(long long); + break; + + case _C_ULNG_LNG: + return sizeof(unsigned long long); + break; + + case _C_FLT: + return sizeof(float); + break; + + case _C_DBL: + return sizeof(double); + break; + + case _C_VOID: + return sizeof(void); + break; + case _C_PTR: + case _C_ATOM: + case _C_CHARPTR: + return sizeof(char*); + break; + + case _C_ARY_B: + { + int len = atoi(type+1); + while (isdigit(*++type)); + return len*objc_aligned_size (type); + } + break; + + case _C_BFLD: + { + /* The new encoding of bitfields is: b 'position' 'type' 'size' */ + int position, size; + int startByte, endByte; + + position = atoi (type + 1); + while (isdigit (*++type)); + size = atoi (type + 1); + + startByte = position / BITS_PER_UNIT; + endByte = (position + size) / BITS_PER_UNIT; + return endByte - startByte; + } + + case _C_STRUCT_B: + { + struct objc_struct_layout layout; + unsigned int size; + + objc_layout_structure (type, &layout); + while (objc_layout_structure_next_member (&layout)) + /* do nothing */ ; + objc_layout_finish_structure (&layout, &size, NULL); + + return size; + } + + case _C_UNION_B: + { + int max_size = 0; + while (*type != _C_UNION_E && *type++ != '=') /* do nothing */; + while (*type != _C_UNION_E) + { + /* Skip the variable name if any */ + if (*type == '"') + { + for (type++; *type++ != '"';) + /* do nothing */; + } + max_size = MAX (max_size, objc_sizeof_type (type)); + type = objc_skip_typespec (type); + } + return max_size; + } + + default: + { + objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type); + return 0; + } + } +} + + +/* + Return the alignment of an object specified by type +*/ + +int +objc_alignof_type(const char* type) +{ + /* Skip the variable name if any */ + if (*type == '"') + { + for (type++; *type++ != '"';) + /* do nothing */; + } + switch(*type) { + case _C_ID: + return __alignof__(id); + break; + + case _C_CLASS: + return __alignof__(Class); + break; + + case _C_SEL: + return __alignof__(SEL); + break; + + case _C_CHR: + return __alignof__(char); + break; + + case _C_UCHR: + return __alignof__(unsigned char); + break; + + case _C_SHT: + return __alignof__(short); + break; + + case _C_USHT: + return __alignof__(unsigned short); + break; + + case _C_INT: + return __alignof__(int); + break; + + case _C_UINT: + return __alignof__(unsigned int); + break; + + case _C_LNG: + return __alignof__(long); + break; + + case _C_ULNG: + return __alignof__(unsigned long); + break; + + case _C_LNG_LNG: + return __alignof__(long long); + break; + + case _C_ULNG_LNG: + return __alignof__(unsigned long long); + break; + + case _C_FLT: + return __alignof__(float); + break; + + case _C_DBL: + return __alignof__(double); + break; + + case _C_PTR: + case _C_ATOM: + case _C_CHARPTR: + return __alignof__(char*); + break; + + case _C_ARY_B: + while (isdigit(*++type)) /* do nothing */; + return objc_alignof_type (type); + + case _C_STRUCT_B: + { + struct objc_struct_layout layout; + unsigned int align; + + objc_layout_structure (type, &layout); + while (objc_layout_structure_next_member (&layout)) + /* do nothing */; + objc_layout_finish_structure (&layout, NULL, &align); + + return align; + } + + case _C_UNION_B: + { + int maxalign = 0; + while (*type != _C_UNION_E && *type++ != '=') /* do nothing */; + while (*type != _C_UNION_E) + { + /* Skip the variable name if any */ + if (*type == '"') + { + for (type++; *type++ != '"';) + /* do nothing */; + } + maxalign = MAX (maxalign, objc_alignof_type (type)); + type = objc_skip_typespec (type); + } + return maxalign; + } + + default: + { + objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type); + return 0; + } + } +} + +/* + The aligned size if the size rounded up to the nearest alignment. +*/ + +int +objc_aligned_size (const char* type) +{ + int size, align; + + /* Skip the variable name */ + if (*type == '"') + { + for (type++; *type++ != '"';) + /* do nothing */; + } + + size = objc_sizeof_type (type); + align = objc_alignof_type (type); + + return ROUND (size, align); +} + +/* + The size rounded up to the nearest integral of the wordsize, taken + to be the size of a void*. +*/ + +int +objc_promoted_size (const char* type) +{ + int size, wordsize; + + /* Skip the variable name */ + if (*type == '"') + { + for (type++; *type++ != '"';) + /* do nothing */; + } + + size = objc_sizeof_type (type); + wordsize = sizeof (void*); + + return ROUND (size, wordsize); +} + +/* + Skip type qualifiers. These may eventually precede typespecs + occurring in method prototype encodings. +*/ + +inline const char* +objc_skip_type_qualifiers (const char* type) +{ + while (*type == _C_CONST + || *type == _C_IN + || *type == _C_INOUT + || *type == _C_OUT + || *type == _C_BYCOPY + || *type == _C_ONEWAY + || *type == _C_GCINVISIBLE) + { + type += 1; + } + return type; +} + + +/* + Skip one typespec element. If the typespec is prepended by type + qualifiers, these are skipped as well. +*/ + +const char* +objc_skip_typespec (const char* type) +{ + /* Skip the variable name if any */ + if (*type == '"') + { + for (type++; *type++ != '"';) + /* do nothing */; + } + + type = objc_skip_type_qualifiers (type); + + switch (*type) { + + case _C_ID: + /* An id may be annotated by the actual type if it is known + with the @"ClassName" syntax */ + + if (*++type != '"') + return type; + else + { + while (*++type != '"') /* do nothing */; + return type + 1; + } + + /* The following are one character type codes */ + case _C_CLASS: + case _C_SEL: + case _C_CHR: + case _C_UCHR: + case _C_CHARPTR: + case _C_ATOM: + case _C_SHT: + case _C_USHT: + case _C_INT: + case _C_UINT: + case _C_LNG: + case _C_ULNG: + case _C_LNG_LNG: + case _C_ULNG_LNG: + case _C_FLT: + case _C_DBL: + case _C_VOID: + case _C_UNDEF: + return ++type; + break; + + case _C_ARY_B: + /* skip digits, typespec and closing ']' */ + + while(isdigit(*++type)); + type = objc_skip_typespec(type); + if (*type == _C_ARY_E) + return ++type; + else + { + objc_error(nil, OBJC_ERR_BAD_TYPE, "bad array type %s\n", type); + return 0; + } + + case _C_BFLD: + /* The new encoding of bitfields is: b 'position' 'type' 'size' */ + while (isdigit (*++type)); /* skip position */ + while (isdigit (*++type)); /* skip type and size */ + return type; + + case _C_STRUCT_B: + /* skip name, and elements until closing '}' */ + + while (*type != _C_STRUCT_E && *type++ != '='); + while (*type != _C_STRUCT_E) { type = objc_skip_typespec (type); } + return ++type; + + case _C_UNION_B: + /* skip name, and elements until closing ')' */ + + while (*type != _C_UNION_E && *type++ != '='); + while (*type != _C_UNION_E) { type = objc_skip_typespec (type); } + return ++type; + + case _C_PTR: + /* Just skip the following typespec */ + + return objc_skip_typespec (++type); + + default: + { + objc_error(nil, OBJC_ERR_BAD_TYPE, "unknown type %s\n", type); + return 0; + } + } +} + +/* + Skip an offset as part of a method encoding. This is prepended by a + '+' if the argument is passed in registers. +*/ +inline const char* +objc_skip_offset (const char* type) +{ + if (*type == '+') type++; + while(isdigit(*++type)); + return type; +} + +/* + Skip an argument specification of a method encoding. +*/ +const char* +objc_skip_argspec (const char* type) +{ + type = objc_skip_typespec (type); + type = objc_skip_offset (type); + return type; +} + +/* + Return the number of arguments that the method MTH expects. + Note that all methods need two implicit arguments `self' and + `_cmd'. +*/ +int +method_get_number_of_arguments (struct objc_method* mth) +{ + int i = 0; + const char* type = mth->method_types; + while (*type) + { + type = objc_skip_argspec (type); + i += 1; + } + return i - 1; +} + +/* + Return the size of the argument block needed on the stack to invoke + the method MTH. This may be zero, if all arguments are passed in + registers. +*/ + +int +method_get_sizeof_arguments (struct objc_method* mth) +{ + const char* type = objc_skip_typespec (mth->method_types); + return atoi (type); +} + +/* + Return a pointer to the next argument of ARGFRAME. type points to + the last argument. Typical use of this look like: + + { + char *datum, *type; + for (datum = method_get_first_argument (method, argframe, &type); + datum; datum = method_get_next_argument (argframe, &type)) + { + unsigned flags = objc_get_type_qualifiers (type); + type = objc_skip_type_qualifiers (type); + if (*type != _C_PTR) + [portal encodeData: datum ofType: type]; + else + { + if ((flags & _F_IN) == _F_IN) + [portal encodeData: *(char**)datum ofType: ++type]; + } + } + } +*/ + +char* +method_get_next_argument (arglist_t argframe, + const char **type) +{ + const char *t = objc_skip_argspec (*type); + + if (*t == '\0') + return 0; + + *type = t; + t = objc_skip_typespec (t); + + if (*t == '+') + return argframe->arg_regs + atoi (++t); + else + return argframe->arg_ptr + atoi (t); +} + +/* + Return a pointer to the value of the first argument of the method + described in M with the given argumentframe ARGFRAME. The type + is returned in TYPE. type must be passed to successive calls of + method_get_next_argument. +*/ +char* +method_get_first_argument (struct objc_method* m, + arglist_t argframe, + const char** type) +{ + *type = m->method_types; + return method_get_next_argument (argframe, type); +} + +/* + Return a pointer to the ARGth argument of the method + M from the frame ARGFRAME. The type of the argument + is returned in the value-result argument TYPE +*/ + +char* +method_get_nth_argument (struct objc_method* m, + arglist_t argframe, int arg, + const char **type) +{ + const char* t = objc_skip_argspec (m->method_types); + + if (arg > method_get_number_of_arguments (m)) + return 0; + + while (arg--) + t = objc_skip_argspec (t); + + *type = t; + t = objc_skip_typespec (t); + + if (*t == '+') + return argframe->arg_regs + atoi (++t); + else + return argframe->arg_ptr + atoi (t); +} + +unsigned +objc_get_type_qualifiers (const char* type) +{ + unsigned res = 0; + BOOL flag = YES; + + while (flag) + switch (*type++) + { + case _C_CONST: res |= _F_CONST; break; + case _C_IN: res |= _F_IN; break; + case _C_INOUT: res |= _F_INOUT; break; + case _C_OUT: res |= _F_OUT; break; + case _C_BYCOPY: res |= _F_BYCOPY; break; + case _C_ONEWAY: res |= _F_ONEWAY; break; + case _C_GCINVISIBLE: res |= _F_GCINVISIBLE; break; + default: flag = NO; + } + + return res; +} + + +/* The following three functions can be used to determine how a + structure is laid out by the compiler. For example: + + struct objc_struct_layout layout; + int i; + + objc_layout_structure (type, &layout); + while (objc_layout_structure_next_member (&layout)) + { + int position, align; + const char *type; + + objc_layout_structure_get_info (&layout, &position, &align, &type); + printf ("element %d has offset %d, alignment %d\n", + i++, position, align); + } + + These functions are used by objc_sizeof_type and objc_alignof_type + functions to compute the size and alignment of structures. The + previous method of computing the size and alignment of a structure + was not working on some architectures, particulary on AIX, and in + the presence of bitfields inside the structure. */ +void +objc_layout_structure (const char *type, + struct objc_struct_layout *layout) +{ + const char *ntype; + + if (*type++ != _C_STRUCT_B) + { + objc_error(nil, OBJC_ERR_BAD_TYPE, + "record type expected in objc_layout_structure, got %s\n", + type); + } + + layout->original_type = type; + + /* Skip "<name>=" if any. Avoid embedded structures and unions. */ + ntype = type; + while (*ntype != _C_STRUCT_E && *ntype != _C_STRUCT_B && *ntype != _C_UNION_B + && *ntype++ != '=') + /* do nothing */; + + /* If there's a "<name>=", ntype - 1 points to '='; skip the the name */ + if (*(ntype - 1) == '=') + type = ntype; + + layout->type = type; + layout->prev_type = NULL; + layout->record_size = 0; + layout->record_align = BITS_PER_UNIT; + +#ifdef STRUCTURE_SIZE_BOUNDARY + layout->record_align = MAX (layout->record_align, STRUCTURE_SIZE_BOUNDARY); +#endif +} + + +BOOL +objc_layout_structure_next_member (struct objc_struct_layout *layout) +{ + register int known_align = layout->record_size; + register int desired_align = 0; + + /* The following are used only if the field is a bitfield */ + register const char *bfld_type; + register int bfld_type_size, bfld_type_align, bfld_field_size; + + /* The current type without the type qualifiers */ + const char *type; + +#if 1 + if (layout->prev_type == NULL) + { + layout->prev_type = layout->type; + layout->type = objc_skip_typespec (layout->prev_type); + return YES; + } +#endif + + /* Add the size of the previous field to the size of the record. */ + if (layout->prev_type) + { + type = objc_skip_type_qualifiers (layout->prev_type); + + if (*type != _C_BFLD) + layout->record_size += objc_sizeof_type (type) * BITS_PER_UNIT; + else { + desired_align = 1; + /* Get the bitfield's type */ + for (bfld_type = type + 1; + isdigit(*bfld_type); + bfld_type++) + /* do nothing */; + + bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT; + bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT; + bfld_field_size = atoi (objc_skip_typespec (bfld_type)); + layout->record_size += bfld_field_size; + } + } + + if (*layout->type == _C_STRUCT_E) + return NO; + + /* Skip the variable name if any */ + if (*layout->type == '"') + { + for (layout->type++; *layout->type++ != '"';) + /* do nothing */; + } + + type = objc_skip_type_qualifiers (layout->type); + + if (*type != _C_BFLD) + desired_align = objc_alignof_type(type) * BITS_PER_UNIT; + else + { + desired_align = 1; + /* Skip the bitfield's offset */ + for (bfld_type = type + 1; isdigit(*bfld_type); bfld_type++) + /* do nothing */; + + bfld_type_size = objc_sizeof_type (bfld_type) * BITS_PER_UNIT; + bfld_type_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT; + bfld_field_size = atoi (objc_skip_typespec (bfld_type)); + } + +#ifdef BIGGEST_FIELD_ALIGNMENT + desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT); +#endif +#ifdef ADJUST_FIELD_ALIGN + desired_align = ADJUST_FIELD_ALIGN (type, desired_align); +#endif + + /* Record must have at least as much alignment as any field. + Otherwise, the alignment of the field within the record + is meaningless. */ +#ifndef PCC_BITFIELD_TYPE_MATTERS + layout->record_align = MAX (layout->record_align, desired_align); +#else + if (*type == _C_BFLD) + { + /* For these machines, a zero-length field does not + affect the alignment of the structure as a whole. + It does, however, affect the alignment of the next field + within the structure. */ + if (bfld_field_size) + layout->record_align = MAX (layout->record_align, desired_align); + else + desired_align = objc_alignof_type (bfld_type) * BITS_PER_UNIT; + + /* A named bit field of declared type `int' + forces the entire structure to have `int' alignment. + Q1: How is encoded this thing and how to check for it? + Q2: How to determine maximum_field_alignment at runtime? */ + +/* if (DECL_NAME (field) != 0) */ + { + int type_align = bfld_type_align; +#if 0 + if (maximum_field_alignment != 0) + type_align = MIN (type_align, maximum_field_alignment); + else if (DECL_PACKED (field)) + type_align = MIN (type_align, BITS_PER_UNIT); +#endif + + layout->record_align = MAX (layout->record_align, type_align); + } + } + else + layout->record_align = MAX (layout->record_align, desired_align); +#endif + + /* Does this field automatically have alignment it needs + by virtue of the fields that precede it and the record's + own alignment? */ + + if (*type == _C_BFLD) + layout->record_size = atoi (type + 1); + else if (layout->record_size % desired_align != 0) + { + /* No, we need to skip space before this field. + Bump the cumulative size to multiple of field alignment. */ + layout->record_size = ROUND (layout->record_size, desired_align); + } + + /* Jump to the next field in record. */ + + layout->prev_type = layout->type; + layout->type = objc_skip_typespec (layout->type); /* skip component */ + + return YES; +} + + +void objc_layout_finish_structure (struct objc_struct_layout *layout, + unsigned int *size, + unsigned int *align) +{ + if (layout->type && *layout->type == _C_STRUCT_E) + { + /* Work out the alignment of the record as one expression and store + in the record type. Round it up to a multiple of the record's + alignment. */ + +#ifdef ROUND_TYPE_ALIGN + layout->record_align = ROUND_TYPE_ALIGN (layout->original_type, + 1, + layout->record_align); +#else + layout->record_align = MAX (1, layout->record_align); +#endif + +#ifdef ROUND_TYPE_SIZE + layout->record_size = ROUND_TYPE_SIZE (layout->original_type, + layout->record_size, + layout->record_align); +#else + /* Round the size up to be a multiple of the required alignment */ + layout->record_size = ROUND (layout->record_size, layout->record_align); +#endif + + layout->type = NULL; + } + if (size) + *size = layout->record_size / BITS_PER_UNIT; + if (align) + *align = layout->record_align / BITS_PER_UNIT; +} + + +void objc_layout_structure_get_info (struct objc_struct_layout *layout, + unsigned int *offset, + unsigned int *align, + const char **type) +{ + if (offset) + *offset = layout->record_size / BITS_PER_UNIT; + if (align) + *align = layout->record_align / BITS_PER_UNIT; + if (type) + *type = layout->prev_type; +} |