/* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ #ifndef _MACHO_NLIST_H_ #define _MACHO_NLIST_H_ /* $NetBSD: nlist.h,v 1.5 1994/10/26 00:56:11 cgd Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)nlist.h 8.2 (Berkeley) 1/21/94 */ /* * Format of a symbol table entry of a Mach-O file. Modified from the BSD * format. The modifications from the original format were changing n_other * (an unused field) to n_sect and the addition of the N_SECT type. These * modifications are required to support symbols in an arbitrary number of * sections not just the three sections (text, data and bss) in a BSD file. */ struct nlist { union { char *n_name; /* for use when in-core */ long n_strx; /* index into the string table */ } n_un; unsigned char n_type; /* type flag, see below */ unsigned char n_sect; /* section number or NO_SECT */ short n_desc; /* see <mach-o/stab.h> */ unsigned long n_value; /* value of this symbol (or stab offset) */ }; /* * Symbols with a index into the string table of zero (n_un.n_strx == 0) are * defined to have a null, "", name. Therefore all string indexes to non null * names must not have a zero string index. This is bit historical information * that has never been well documented. */ /* * The n_type field really contains three fields: * unsigned char N_STAB:3, * N_PEXT:1, * N_TYPE:3, * N_EXT:1; * which are used via the following masks. */ #define N_STAB 0xe0 /* if any of these bits set, a symbolic debugging entry */ #define N_PEXT 0x10 /* private external symbol bit */ #define N_TYPE 0x0e /* mask for the type bits */ #define N_EXT 0x01 /* external symbol bit, set for external symbols */ /* * Only symbolic debugging entries have some of the N_STAB bits set and if any * of these bits are set then it is a symbolic debugging entry (a stab). In * which case then the values of the n_type field (the entire field) are given * in <mach-o/stab.h> */ /* * Values for N_TYPE bits of the n_type field. */ #define N_UNDF 0x0 /* undefined, n_sect == NO_SECT */ #define N_ABS 0x2 /* absolute, n_sect == NO_SECT */ #define N_SECT 0xe /* defined in section number n_sect */ #define N_PBUD 0xc /* prebound undefined (defined in a dylib) */ #define N_INDR 0xa /* indirect */ /* * If the type is N_INDR then the symbol is defined to be the same as another * symbol. In this case the n_value field is an index into the string table * of the other symbol's name. When the other symbol is defined then they both * take on the defined type and value. */ /* * If the type is N_SECT then the n_sect field contains an ordinal of the * section the symbol is defined in. The sections are numbered from 1 and * refer to sections in order they appear in the load commands for the file * they are in. This means the same ordinal may very well refer to different * sections in different files. * * The n_value field for all symbol table entries (including N_STAB's) gets * updated by the link editor based on the value of it's n_sect field and where * the section n_sect references gets relocated. If the value of the n_sect * field is NO_SECT then it's n_value field is not changed by the link editor. */ #define NO_SECT 0 /* symbol is not in any section */ #define MAX_SECT 255 /* 1 thru 255 inclusive */ /* * Common symbols are represented by undefined (N_UNDF) external (N_EXT) types * who's values (n_value) are non-zero. In which case the value of the n_value * field is the size (in bytes) of the common symbol. The n_sect field is set * to NO_SECT. */ /* * To support the lazy binding of undefined symbols in the dynamic link-editor, * the undefined symbols in the symbol table (the nlist structures) are marked * with the indication if the undefined reference is a lazy reference or * non-lazy reference. If both a non-lazy reference and a lazy reference is * made to the same symbol the non-lazy reference takes precedence. A reference * is lazy only when all references to that symbol are made through a symbol * pointer in a lazy symbol pointer section. * * The implementation of marking nlist structures in the symbol table for * undefined symbols will be to use some of the bits of the n_desc field as a * reference type. The mask REFERENCE_TYPE will be applied to the n_desc field * of an nlist structure for an undefined symbol to determine the type of * undefined reference (lazy or non-lazy). * * The constants for the REFERENCE FLAGS are propagated to the reference table * in a shared library file. In that case the constant for a defined symbol, * REFERENCE_FLAG_DEFINED, is also used. */ /* Reference type bits of the n_desc field of undefined symbols */ #define REFERENCE_TYPE 0xf /* types of references */ #define REFERENCE_FLAG_UNDEFINED_NON_LAZY 0 #define REFERENCE_FLAG_UNDEFINED_LAZY 1 #define REFERENCE_FLAG_DEFINED 2 #define REFERENCE_FLAG_PRIVATE_DEFINED 3 #define REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY 4 #define REFERENCE_FLAG_PRIVATE_UNDEFINED_LAZY 5 /* * To simplify stripping of objects that use are used with the dynamic link * editor, the static link editor marks the symbols defined an object that are * referenced by a dynamicly bound object (dynamic shared libraries, bundles). * With this marking strip knows not to strip these symbols. */ #define REFERENCED_DYNAMICALLY 0x0010 /* * The non-reference type bits of the n_desc field for global symbols are * reserved for the dynamic link editor. All of these bits must start out * zero in the object file. */ #define N_DESC_DISCARDED 0x8000 /* symbol is discarded */ #endif