X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/ff6e181ae92fc6f1e89841290f461d1f2f9badd9..HEAD:/EXTERNAL_HEADERS/mach-o/nlist.h diff --git a/EXTERNAL_HEADERS/mach-o/nlist.h b/EXTERNAL_HEADERS/mach-o/nlist.h index 31409836e..133e36b49 100644 --- a/EXTERNAL_HEADERS/mach-o/nlist.h +++ b/EXTERNAL_HEADERS/mach-o/nlist.h @@ -1,6 +1,6 @@ /* - * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. - * + * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. + * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code @@ -63,39 +63,42 @@ * * @(#)nlist.h 8.2 (Berkeley) 1/21/94 */ +#include /* - * 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. + * Format of a symbol table entry of a Mach-O file for 32-bit architectures. + * 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 a larger + * number of sections not just the three sections (text, data and bss) in a BSD + * file. */ struct nlist { union { +#ifndef __LP64__ char *n_name; /* for use when in-core */ - long n_strx; /* index into the string table */ +#endif + uint32_t 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 */ - unsigned long n_value; /* value of this symbol (or stab offset) */ + uint8_t n_type; /* type flag, see below */ + uint8_t n_sect; /* section number or NO_SECT */ + int16_t n_desc; /* see */ + uint32_t n_value; /* value of this symbol (or stab offset) */ }; /* * This is the symbol table entry structure for 64-bit architectures. */ struct nlist_64 { - union { - uint32_t n_strx; /* index into the string table */ - } n_un; - uint8_t n_type; /* type flag, see below */ - uint8_t n_sect; /* section number or NO_SECT */ - uint16_t n_desc; /* see */ - uint64_t n_value; /* value of this symbol (or stab offset) */ + union { + uint32_t n_strx; /* index into the string table */ + } n_un; + uint8_t n_type; /* type flag, see below */ + uint8_t n_sect; /* section number or NO_SECT */ + uint16_t n_desc; /* see */ + uint64_t 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 @@ -104,7 +107,7 @@ struct nlist_64 { */ /* - * The n_type field really contains three fields: + * The n_type field really contains four fields: * unsigned char N_STAB:3, * N_PEXT:1, * N_TYPE:3, @@ -158,8 +161,14 @@ struct nlist_64 { * 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 NO_SECT. The alignment of a common symbol may be set as a power of 2 + * between 2^1 and 2^15 as part of the n_desc field using the macros below. If + * the alignment is not set (a value of zero) then natural alignment based on + * the size is used. */ +#define GET_COMM_ALIGN(n_desc) (((n_desc) >> 8) & 0x0f) +#define SET_COMM_ALIGN(n_desc,align) \ + (n_desc) = (((n_desc) & 0xf0ff) | (((align) & 0x0f) << 8)) /* * To support the lazy binding of undefined symbols in the dynamic link-editor, @@ -181,7 +190,7 @@ struct nlist_64 { * REFERENCE_FLAG_DEFINED, is also used. */ /* Reference type bits of the n_desc field of undefined symbols */ -#define REFERENCE_TYPE 0xf +#define REFERENCE_TYPE 0x7 /* types of references */ #define REFERENCE_FLAG_UNDEFINED_NON_LAZY 0 #define REFERENCE_FLAG_UNDEFINED_LAZY 1 @@ -199,10 +208,111 @@ struct nlist_64 { #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. + * For images created by the static link editor with the -twolevel_namespace + * option in effect the flags field of the mach header is marked with + * MH_TWOLEVEL. And the binding of the undefined references of the image are + * determined by the static link editor. Which library an undefined symbol is + * bound to is recorded by the static linker in the high 8 bits of the n_desc + * field using the SET_LIBRARY_ORDINAL macro below. The ordinal recorded + * references the libraries listed in the Mach-O's LC_LOAD_DYLIB, + * LC_LOAD_WEAK_DYLIB, LC_REEXPORT_DYLIB, LC_LOAD_UPWARD_DYLIB, and + * LC_LAZY_LOAD_DYLIB, etc. load commands in the order they appear in the + * headers. The library ordinals start from 1. + * For a dynamic library that is built as a two-level namespace image the + * undefined references from module defined in another use the same nlist struct + * an in that case SELF_LIBRARY_ORDINAL is used as the library ordinal. For + * defined symbols in all images they also must have the library ordinal set to + * SELF_LIBRARY_ORDINAL. The EXECUTABLE_ORDINAL refers to the executable + * image for references from plugins that refer to the executable that loads + * them. + * + * The DYNAMIC_LOOKUP_ORDINAL is for undefined symbols in a two-level namespace + * image that are looked up by the dynamic linker with flat namespace semantics. + * This ordinal was added as a feature in Mac OS X 10.3 by reducing the + * value of MAX_LIBRARY_ORDINAL by one. So it is legal for existing binaries + * or binaries built with older tools to have 0xfe (254) dynamic libraries. In + * this case the ordinal value 0xfe (254) must be treated as a library ordinal + * for compatibility. */ -#define N_DESC_DISCARDED 0x8000 /* symbol is discarded */ +#define GET_LIBRARY_ORDINAL(n_desc) (((n_desc) >> 8) & 0xff) +#define SET_LIBRARY_ORDINAL(n_desc,ordinal) \ + (n_desc) = (((n_desc) & 0x00ff) | (((ordinal) & 0xff) << 8)) +#define SELF_LIBRARY_ORDINAL 0x0 +#define MAX_LIBRARY_ORDINAL 0xfd +#define DYNAMIC_LOOKUP_ORDINAL 0xfe +#define EXECUTABLE_ORDINAL 0xff -#endif +/* + * The bit 0x0020 of the n_desc field is used for two non-overlapping purposes + * and has two different symbolic names, N_NO_DEAD_STRIP and N_DESC_DISCARDED. + */ + +/* + * The N_NO_DEAD_STRIP bit of the n_desc field only ever appears in a + * relocatable .o file (MH_OBJECT filetype). And is used to indicate to the + * static link editor it is never to dead strip the symbol. + */ +#define N_NO_DEAD_STRIP 0x0020 /* symbol is not to be dead stripped */ + +/* + * The N_DESC_DISCARDED bit of the n_desc field never appears in linked image. + * But is used in very rare cases by the dynamic link editor to mark an in + * memory symbol as discared and longer used for linking. + */ +#define N_DESC_DISCARDED 0x0020 /* symbol is discarded */ + +/* + * The N_WEAK_REF bit of the n_desc field indicates to the dynamic linker that + * the undefined symbol is allowed to be missing and is to have the address of + * zero when missing. + */ +#define N_WEAK_REF 0x0040 /* symbol is weak referenced */ + +/* + * The N_WEAK_DEF bit of the n_desc field indicates to the static and dynamic + * linkers that the symbol definition is weak, allowing a non-weak symbol to + * also be used which causes the weak definition to be discared. Currently this + * is only supported for symbols in coalesed sections. + */ +#define N_WEAK_DEF 0x0080 /* coalesed symbol is a weak definition */ + +/* + * The N_REF_TO_WEAK bit of the n_desc field indicates to the dynamic linker + * that the undefined symbol should be resolved using flat namespace searching. + */ +#define N_REF_TO_WEAK 0x0080 /* reference to a weak symbol */ + +/* + * The N_ARM_THUMB_DEF bit of the n_desc field indicates that the symbol is + * a defintion of a Thumb function. + */ +#define N_ARM_THUMB_DEF 0x0008 /* symbol is a Thumb function (ARM) */ + +/* + * The N_SYMBOL_RESOLVER bit of the n_desc field indicates that the + * that the function is actually a resolver function and should + * be called to get the address of the real function to use. + * This bit is only available in .o files (MH_OBJECT filetype) + */ +#define N_SYMBOL_RESOLVER 0x0100 + +/* + * The N_ALT_ENTRY bit of the n_desc field indicates that the + * symbol is pinned to the previous content. + */ +#define N_ALT_ENTRY 0x0200 + +#ifndef __STRICT_BSD__ +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ +/* + * The function nlist(3) from the C library. + */ +extern int nlist (const char *filename, struct nlist *list); +#ifdef __cplusplus +} +#endif /* __cplusplus */ +#endif /* __STRICT_BSD__ */ + +#endif /* _MACHO_LIST_H_ */