--- /dev/null
+/* Support macros for making weak and strong aliases for symbols,
+ and for using symbol sets and linker warnings with GNU ld.
+ Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#ifndef _LIBC_SYMBOLS_H
+#define _LIBC_SYMBOLS_H 1
+
+/* This file's macros are included implicitly in the compilation of every
+ file in the C library by -imacros.
+
+ We include config.h which is generated by configure.
+ It should define for us the following symbols:
+
+ * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
+ * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'.
+ * HAVE_GNU_LD if using GNU ld, with support for weak symbols in a.out,
+ and for symbol set and warning messages extensions in a.out and ELF.
+ * HAVE_ELF if using ELF, which supports weak symbols using `.weak'.
+ * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
+ * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
+
+ */
+
+/* This is defined for the compilation of all C library code. features.h
+ tests this to avoid inclusion of stubs.h while compiling the library,
+ before stubs.h has been generated. Some library code that is shared
+ with other packages also tests this symbol to see if it is being
+ compiled as part of the C library. We must define this before including
+ config.h, because it makes some definitions conditional on whether libc
+ itself is being compiled, or just some generator program. */
+#define _LIBC 1
+
+/* Enable declarations of GNU extensions, since we are compiling them. */
+#define _GNU_SOURCE 1
+/* And we also need the data for the reentrant functions. */
+#define _REENTRANT 1
+
+#include <config.h>
+/*
+\f
+*/
+
+#ifndef ASSEMBLER
+
+/* Define the macros `_' and `N_' for conveniently marking translatable
+ strings in the libc source code. */
+
+#define N_(msgid) msgid
+
+#include <libintl.h>
+extern const char _libc_intl_domainname[];
+
+#ifdef dgettext
+/* This is defined as an optimizing macro, so use it. */
+#define _(msgid) dgettext (_libc_intl_domainname, (msgid))
+#else
+/* Be sure to use only the __ name when `dgettext' is a plain function
+ instead of an optimizing macro. */
+#define _(msgid) __dgettext (_libc_intl_domainname, (msgid))
+#endif
+
+#endif
+
+/*
+\f
+*/
+/* The symbols in all the user (non-_) macros are C symbols.
+ HAVE_GNU_LD without HAVE_ELF implies a.out. */
+
+#if defined (HAVE_ASM_WEAK_DIRECTIVE) || defined (HAVE_ASM_WEAKEXT_DIRECTIVE)
+#define HAVE_WEAK_SYMBOLS
+#endif
+
+#ifndef __SYMBOL_PREFIX
+#ifdef NO_UNDERSCORES
+#define __SYMBOL_PREFIX
+#else
+#define __SYMBOL_PREFIX "_"
+#endif
+#endif
+
+#ifndef C_SYMBOL_NAME
+#ifdef NO_UNDERSCORES
+#define C_SYMBOL_NAME(name) name
+#else
+#define C_SYMBOL_NAME(name) _##name
+#endif
+#endif
+
+
+/* Define ALIAS as a strong alias for ORIGINAL. */
+#ifdef HAVE_ASM_SET_DIRECTIVE
+#define strong_alias_asm(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias); \
+ .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
+#ifdef ASSEMBLER
+#define strong_alias(original, alias) strong_alias_asm (original, alias)
+#else
+#define strong_alias(original, alias) \
+ asm (__string_1 (ASM_GLOBAL_DIRECTIVE) " " __SYMBOL_PREFIX #alias "\n" \
+ ".set " __SYMBOL_PREFIX #alias "," __SYMBOL_PREFIX #original);
+#endif
+#else
+#define strong_alias_asm(original, alias) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias); \
+ C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
+#ifdef ASSEMBLER
+#define strong_alias(original, alias) strong_alias_asm (original, alias)
+#else
+#define strong_alias(original, alias) \
+ asm (__string_1 (ASM_GLOBAL_DIRECTIVE) " " __SYMBOL_PREFIX #alias "\n" \
+ __SYMBOL_PREFIX #alias " = " __SYMBOL_PREFIX #original);
+#endif
+#endif
+
+/* Helper macros used above. */
+#define __string_1(x) __string_0(x)
+#define __string_0(x) #x
+
+
+#ifdef HAVE_WEAK_SYMBOLS
+
+#ifdef ASSEMBLER
+
+#ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
+
+/* Define ALIAS as a weak alias for ORIGINAL.
+ If weak aliases are not available, this defines a strong alias. */
+#define weak_alias(original, alias) \
+ .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
+
+/* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined). */
+#define weak_extern(symbol) \
+ .weakext C_SYMBOL_NAME (symbol)
+
+#else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
+
+/* Define ALIAS as a weak alias for ORIGINAL.
+ If weak aliases are not available, this defines a strong alias. */
+#define weak_alias(original, alias) \
+ .weak C_SYMBOL_NAME (alias); \
+ C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
+
+
+/* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined). */
+#define weak_extern(symbol) \
+ .weak C_SYMBOL_NAME (symbol)
+
+#endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
+
+#else /* ! ASSEMBLER */
+
+#ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
+#define weak_extern_asm(symbol) asm (".weakext " __SYMBOL_PREFIX #symbol);
+#define weak_alias_asm(original, alias) \
+ asm (".weakext " __SYMBOL_PREFIX #alias ", " __SYMBOL_PREFIX #original);
+#else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
+#define weak_extern_asm(symbol) asm (".weak " __SYMBOL_PREFIX #symbol);
+#define weak_alias_asm(original, alias) \
+ asm (".weak " __SYMBOL_PREFIX #alias "\n" \
+ __SYMBOL_PREFIX #alias " = " __SYMBOL_PREFIX #original);
+#endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
+
+#define weak_alias(o, a) weak_alias_asm (o, a)
+#define weak_extern(symbol) weak_extern_asm (symbol)
+
+#endif /* ! ASSEMBLER */
+#else
+#define weak_alias(original, alias) strong_alias(original, alias)
+#define weak_extern(symbol) /* Do nothing; the ref will be strong. */
+#endif
+
+
+#if (!defined (ASSEMBLER) && \
+ (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)))
+/* GCC 2.7 and later has special syntax for weak symbols and aliases.
+ Using that is better when possible, because the compiler and assembler
+ are better clued in to what we are doing. */
+#undef strong_alias
+#define strong_alias(name, aliasname) \
+ extern __typeof (name) aliasname __attribute__ ((alias (#name)));
+
+#ifdef HAVE_WEAK_SYMBOLS
+#undef weak_alias
+#define weak_alias(name, aliasname) \
+ extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
+
+/* This comes between the return type and function name in
+ a function definition to make that definition weak. */
+#define weak_function __attribute__ ((weak))
+#define weak_const_function __attribute__ ((weak, __const__))
+
+#endif /* HAVE_WEAK_SYMBOLS. */
+#endif /* Not ASSEMBLER, and GCC 2.7 or later. */
+
+
+#ifndef weak_function
+/* If we do not have the __attribute__ ((weak)) syntax, there is no way we
+ can define functions as weak symbols. The compiler will emit a `.globl'
+ directive for the function symbol, and a `.weak' directive in addition
+ will produce an error from the assembler. */
+#define weak_function /* empty */
+#define weak_const_function /* empty */
+#endif
+
+
+/* When a reference to SYMBOL is encountered, the linker will emit a
+ warning message MSG. */
+#ifdef HAVE_GNU_LD
+#ifdef HAVE_ELF
+
+/* We want the .gnu.warning.SYMBOL section to be unallocated. */
+#ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
+#define __make_section_unallocated(section_string) \
+ asm(".section " section_string "; .previous");
+#elif defined (HAVE_ASM_POPSECTION_DIRECTIVE)
+#define __make_section_unallocated(section_string) \
+ asm(".pushsection " section_string "; .popsection");
+#else
+#define __make_section_unallocated(section_string)
+#endif
+
+#define link_warning(symbol, msg) \
+ __make_section_unallocated (".gnu.warning." #symbol) \
+ static const char __evoke_link_warning_##symbol[] \
+ __attribute__ ((section (".gnu.warning." #symbol))) = msg;
+#else
+#define link_warning(symbol, msg) \
+ asm(".stabs \"" msg "\",30,0,0,0\n" \
+ ".stabs \"" __SYMBOL_PREFIX #symbol "\",1,0,0,0\n");
+#endif
+#else
+/* We will never be heard; they will all die horribly. */
+#define link_warning(symbol, msg)
+#endif
+
+/* A canned warning for sysdeps/stub functions. */
+#define stub_warning(name) \
+ link_warning (name, \
+ "warning: " #name " is not implemented and will always fail")
+
+/*
+\f
+*/
+
+#ifdef HAVE_GNU_LD
+
+/* Symbol set support macros. */
+
+#ifdef HAVE_ELF
+
+/* Make SYMBOL, which is in the text segment, an element of SET. */
+#define text_set_element(set, symbol) _elf_set_element(set, symbol)
+/* Make SYMBOL, which is in the data segment, an element of SET. */
+#define data_set_element(set, symbol) _elf_set_element(set, symbol)
+/* Make SYMBOL, which is in the bss segment, an element of SET. */
+#define bss_set_element(set, symbol) _elf_set_element(set, symbol)
+
+/* These are all done the same way in ELF.
+ There is a new section created for each set. */
+#ifdef PIC
+/* When building a shared library, make the set section writable,
+ because it will need to be relocated at run time anyway. */
+#define _elf_set_element(set, symbol) \
+ static const void *__elf_set_##set##_element_##symbol##__ \
+ __attribute__ ((unused, section (#set))) = &(symbol)
+#else
+#define _elf_set_element(set, symbol) \
+ static const void *const __elf_set_##set##_element_##symbol##__ \
+ __attribute__ ((unused, section (#set))) = &(symbol)
+#endif
+
+/* Define SET as a symbol set. This may be required (it is in a.out) to
+ be able to use the set's contents. */
+#define symbol_set_define(set) symbol_set_declare(set)
+
+/* Declare SET for use in this module, if defined in another module. */
+#define symbol_set_declare(set) \
+ extern void *const __start_##set __attribute__ ((__weak__)); \
+ extern void *const __stop_##set __attribute__ ((__weak__)); \
+ weak_extern (__start_##set) weak_extern (__stop_##set)
+
+/* Return a pointer (void *const *) to the first element of SET. */
+#define symbol_set_first_element(set) (&__start_##set)
+
+/* Return true iff PTR (a void *const *) has been incremented
+ past the last element in SET. */
+#define symbol_set_end_p(set, ptr) ((ptr) >= &__stop_##set)
+
+#else /* Not ELF: a.out. */
+
+#define text_set_element(set, symbol) \
+ asm(".stabs \"" __SYMBOL_PREFIX #set "\",23,0,0," __SYMBOL_PREFIX #symbol)
+#define data_set_element(set, symbol) \
+ asm(".stabs \"" __SYMBOL_PREFIX #set "\",25,0,0," __SYMBOL_PREFIX #symbol)
+#define bss_set_element(set, symbol) ?error Must use initialized data.
+#define symbol_set_define(set) void *const (set)[1];
+#define symbol_set_declare(set) extern void *const (set)[1];
+
+#define symbol_set_first_element(set) &(set)[1]
+#define symbol_set_end_p(set, ptr) (*(ptr) == 0)
+
+#endif /* ELF. */
+#endif /* Have GNU ld. */
+
+#endif /* libc-symbols.h */
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