/* Support macros for making weak and strong aliases for symbols,
and for using symbol sets and linker warnings with GNU ld.
- Copyright (C) 1995-1998,2000-2006,2008,2009,2011,2012
- Free Software Foundation, Inc.
+ Copyright (C) 1995-2017 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
#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.
+/* This file is included implicitly in the compilation of every source file,
+ using -include. It includes config.h. */
- We include config.h which is generated by configure.
- It should define for us the following symbols:
+/* Enable declarations of GNU extensions, since we are compiling them. */
+#define _GNU_SOURCE 1
+
+#ifdef MODULE_NAME
+
+/* Use `#if IS_IN (module)` to detect what component is being compiled. */
+#define PASTE_NAME1(a,b) a##b
+#define PASTE_NAME(a,b) PASTE_NAME1 (a,b)
+#define IN_MODULE PASTE_NAME (MODULE_, MODULE_NAME)
+#define IS_IN(lib) (IN_MODULE == MODULE_##lib)
+
+/* True if the current module is a versioned library. Versioned
+ library names culled from shlib-versions files are assigned a
+ MODULE_* value greater than MODULE_LIBS_BEGIN. */
+#define IS_IN_LIB (IN_MODULE > MODULE_LIBS_BEGIN)
+
+/* The testsuite, and some other ancillary code, should be compiled against
+ as close an approximation to the installed headers as possible.
+ Defining this symbol disables most internal-use-only declarations
+ provided by this header, and all those provided by other internal
+ wrapper headers. */
+#if IS_IN (testsuite) || defined IS_IN_build || defined __cplusplus
+# define _ISOMAC 1
+#endif
- * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
- * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'.
- * ASM_TYPE_DIRECTIVE_PREFIX with `@' or `#' or whatever for .type,
- or leave it undefined if there is no .type directive.
- * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
- * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
+#else
+/* The generation process for a few files created very early in the
+ build (notably libc-modules.h itself) involves preprocessing this
+ header without defining MODULE_NAME. Under these conditions,
+ internal declarations (especially from config.h) must be visible,
+ but IS_IN should always evaluate as false. */
+# define IS_IN(lib) 0
+# define IS_IN_LIB 0
+# define IN_MODULE (-1)
+#endif
- */
+#ifndef _ISOMAC
/* 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,
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
+/* Some files must be compiled with optimization on. */
+#if !defined __ASSEMBLER__ && !defined __OPTIMIZE__
+# error "glibc cannot be compiled without optimization"
+#endif
+
+/* -ffast-math cannot be applied to the C library, as it alters the ABI.
+ Some test components that use -ffast-math are currently not part of
+ IS_IN (testsuite) for technical reasons, so we have a secondary override. */
+#if defined __FAST_MATH__ && !defined TEST_FAST_MATH
+# error "glibc must not be compiled with -ffast-math"
+#endif
#include <config.h>
-/* The symbols in all the user (non-_) macros are C symbols. */
+/* Define this for the benefit of portable GNU code that wants to check it.
+ Code that checks with #if will not #include <config.h> again, since we've
+ already done it (and this file is implicitly included in every compile,
+ via -include). Code that checks with #ifdef will #include <config.h>,
+ but that file should always be idempotent (i.e., it's just #define/#undef
+ and nothing else anywhere should be changing the macro state it touches),
+ so it's harmless. */
+#define HAVE_CONFIG_H 0
+
+/* Define these macros for the benefit of portable GNU code that wants to check
+ them. Of course, STDC_HEADERS is never false when building libc! */
+#define STDC_HEADERS 1
+#define HAVE_MBSTATE_T 1
+#define HAVE_MBSRTOWCS 1
+#define HAVE_LIBINTL_H 1
+#define HAVE_WCTYPE_H 1
+#define HAVE_ISWCTYPE 1
+#define ENABLE_NLS 1
-#if !defined HAVE_ASM_WEAK_DIRECTIVE && !defined HAVE_ASM_WEAKEXT_DIRECTIVE
-# error "weak symbol support needed"
-#endif
+/* The symbols in all the user (non-_) macros are C symbols. */
#ifndef __SYMBOL_PREFIX
# define __SYMBOL_PREFIX
# define ASM_LINE_SEP ;
#endif
-#ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# ifndef C_SYMBOL_DOT_NAME
-# if defined __GNUC__ && defined __GNUC_MINOR__ \
- && (__GNUC__ << 16) + __GNUC_MINOR__ >= (3 << 16) + 1
-# define C_SYMBOL_DOT_NAME(name) .name
-# else
-# define C_SYMBOL_DOT_NAME(name) .##name
-# endif
-# endif
-#endif
-
#ifndef __ASSEMBLER__
/* GCC understands weak symbols and aliases; use its interface where
possible, instead of embedded assembly language. */
# define weak_extern(symbol) _weak_extern (weak symbol)
# define _weak_extern(expr) _Pragma (#expr)
+/* In shared builds, the expression call_function_static_weak
+ (FUNCTION-SYMBOL, ARGUMENTS) invokes FUNCTION-SYMBOL (an
+ identifier) unconditionally, with the (potentially empty) argument
+ list ARGUMENTS. In static builds, if FUNCTION-SYMBOL has a
+ definition, the function is invoked as before; if FUNCTION-SYMBOL
+ is NULL, no call is performed. */
+# ifdef SHARED
+# define call_function_static_weak(func, ...) func (__VA_ARGS__)
+# else /* !SHARED */
+# define call_function_static_weak(func, ...) \
+ ({ \
+ extern __typeof__ (func) func weak_function; \
+ (func != NULL ? func (__VA_ARGS__) : (void)0); \
+ })
+# endif
#else /* __ASSEMBLER__ */
# ifdef HAVE_ASM_SET_DIRECTIVE
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
-# define strong_data_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
+# define strong_alias(original, alias) \
+ .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP \
.set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
-# else
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
-# define strong_data_alias(original, alias) strong_alias(original, alias)
-# endif
+# define strong_data_alias(original, alias) strong_alias(original, alias)
# else
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
-# define strong_data_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
-# else
-# define strong_alias(original, alias) \
- ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP \
+# define strong_alias(original, alias) \
+ .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP \
C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
-# define strong_data_alias(original, alias) strong_alias(original, alias)
-# endif
+# define strong_data_alias(original, alias) strong_alias(original, alias)
# endif
-# ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define weak_alias(original, alias) \
- .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
- .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
-# else
-# define weak_alias(original, alias) \
- .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
-# endif
-# define weak_extern(symbol) \
- .weakext C_SYMBOL_NAME (symbol)
-
-# else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
-
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define weak_alias(original, alias) \
- .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP \
- .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP \
- C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
-# else
-# define weak_alias(original, alias) \
+# define weak_alias(original, alias) \
.weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \
C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
-# endif
-# define weak_extern(symbol) \
+# define weak_extern(symbol) \
.weak C_SYMBOL_NAME (symbol)
-# endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
-
#endif /* __ASSEMBLER__ */
/* On some platforms we can make internal function calls (i.e., calls of
/* When a reference to SYMBOL is encountered, the linker will emit a
warning message MSG. */
/* We want the .gnu.warning.SYMBOL section to be unallocated. */
-#ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
-# define __make_section_unallocated(section_string) \
+#define __make_section_unallocated(section_string) \
asm (".section " section_string "\n\t.previous");
-#elif defined HAVE_ASM_POPSECTION_DIRECTIVE
-# define __make_section_unallocated(section_string) \
- asm (".pushsection " section_string "\n\t.popsection");
-#else
-# define __make_section_unallocated(section_string)
-#endif
/* Tacking on "\n\t#" to the section name makes gcc put it's bogus
section attributes on what looks like a comment to the assembler. */
/* A canned warning for sysdeps/stub functions. */
#define stub_warning(name) \
__make_section_unallocated (".gnu.glibc-stub." #name) \
- link_warning (name, \
- "warning: " #name " is not implemented and will always fail")
+ link_warning (name, #name " is not implemented and will always fail")
/* Warning for linking functions calling dlopen into static binaries. */
#ifdef SHARED
thinks it is. */
#define declare_symbol_alias(symbol, original, type, size) \
declare_symbol_alias_1 (symbol, original, type, size)
-#ifdef ASM_TYPE_DIRECTIVE_PREFIX
-# ifdef __ASSEMBLER__
-# define declare_symbol_alias_1(symbol, original, type, size) \
- strong_alias (original, symbol); \
- .type C_SYMBOL_NAME (symbol), \
- declare_symbol_alias_1_paste (ASM_TYPE_DIRECTIVE_PREFIX, type); \
- .size C_SYMBOL_NAME (symbol), size
-# define declare_symbol_alias_1_paste(a, b) \
- declare_symbol_alias_1_paste_1 (a,b)
-# define declare_symbol_alias_1_paste_1(a,b) a##b
-# else /* Not __ASSEMBLER__. */
-# define declare_symbol_alias_1(symbol, original, type, size) \
- asm (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE) \
- " " __SYMBOL_PREFIX #symbol \
- "\n\t" declare_symbol_alias_1_alias (symbol, original) \
- "\n\t.type " __SYMBOL_PREFIX #symbol ", " \
- declare_symbol_alias_1_stringify (ASM_TYPE_DIRECTIVE_PREFIX) #type \
- "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
-# define declare_symbol_alias_1_stringify(x) \
- declare_symbol_alias_1_stringify_1 (x)
-# define declare_symbol_alias_1_stringify_1(x) #x
-# ifdef HAVE_ASM_SET_DIRECTIVE
-# define declare_symbol_alias_1_alias(symbol, original) \
- ".set " __SYMBOL_PREFIX #symbol ", " __SYMBOL_PREFIX #original
-# else
-# define declare_symbol_alias_1_alias(symbol, original) \
- __SYMBOL_PREFIX #symbol " = " __SYMBOL_PREFIX #original
-# endif /* HAVE_ASM_SET_DIRECTIVE */
-# endif /* __ASSEMBLER__ */
-#else
-# define declare_symbol_1(symbol, type, size) /* Nothing. */
-#endif
+#ifdef __ASSEMBLER__
+# define declare_symbol_alias_1(symbol, original, type, size) \
+ strong_alias (original, symbol); \
+ .type C_SYMBOL_NAME (symbol), %##type; \
+ .size C_SYMBOL_NAME (symbol), size
+#else /* Not __ASSEMBLER__. */
+# define declare_symbol_alias_1(symbol, original, type, size) \
+ asm (".globl " __SYMBOL_PREFIX #symbol \
+ "\n\t" declare_symbol_alias_1_alias (symbol, original) \
+ "\n\t.type " __SYMBOL_PREFIX #symbol ", " \
+ "%" #type \
+ "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
+# ifdef HAVE_ASM_SET_DIRECTIVE
+# define declare_symbol_alias_1_alias(symbol, original) \
+ ".set " __SYMBOL_PREFIX #symbol ", " __SYMBOL_PREFIX #original
+# else
+# define declare_symbol_alias_1_alias(symbol, original) \
+ __SYMBOL_PREFIX #symbol " = " __SYMBOL_PREFIX #original
+# endif /* HAVE_ASM_SET_DIRECTIVE */
+#endif /* __ASSEMBLER__ */
/*
past the last element in SET. */
#define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set)
-#if DO_VERSIONING
+/* Use symbol_version_reference to specify the version a symbol
+ reference should link to. Use symbol_version or
+ default_symbol_version for the definition of a versioned symbol.
+ The difference is that the latter is a no-op in non-shared
+ builds. */
+#ifdef __ASSEMBLER__
+# define symbol_version_reference(real, name, version) \
+ .symver real, name##@##version
+#else /* !__ASSEMBLER__ */
+# define symbol_version_reference(real, name, version) \
+ __asm__ (".symver " #real "," #name "@" #version)
+#endif
+
+#ifdef SHARED
# define symbol_version(real, name, version) \
- _symbol_version(real, name, version)
+ symbol_version_reference(real, name, version)
# define default_symbol_version(real, name, version) \
_default_symbol_version(real, name, version)
# ifdef __ASSEMBLER__
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define _symbol_version(real, name, version) \
- .symver real, name##@##version ASM_LINE_SEP \
- .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##version)
-# define _default_symbol_version(real, name, version) \
- .symver real, name##@##@##version ASM_LINE_SEP \
- .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##@##version)
-# else
-# define _symbol_version(real, name, version) \
- .symver real, name##@##version
-# define _default_symbol_version(real, name, version) \
+# define _default_symbol_version(real, name, version) \
.symver real, name##@##@##version
-# endif
# else
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define _symbol_version(real, name, version) \
- __asm__ (".symver " #real "," #name "@" #version "\n\t" \
- ".symver ." #real ",." #name "@" #version)
-# define _default_symbol_version(real, name, version) \
- __asm__ (".symver " #real "," #name "@@" #version "\n\t" \
- ".symver ." #real ",." #name "@@" #version)
-# else
-# define _symbol_version(real, name, version) \
- __asm__ (".symver " #real "," #name "@" #version)
-# define _default_symbol_version(real, name, version) \
+# define _default_symbol_version(real, name, version) \
__asm__ (".symver " #real "," #name "@@" #version)
-# endif
# endif
#else
# define symbol_version(real, name, version)
#define attribute_relro __attribute__ ((section (".data.rel.ro")))
-/* Handling on non-exported internal names. We have to do this only
- for shared code. */
-#ifdef SHARED
-# define INTUSE(name) name##_internal
-# define INTDEF(name) strong_alias (name, name##_internal)
-# define INTVARDEF(name) \
- _INTVARDEF (name, name##_internal)
-# define _INTVARDEF(name, aliasname) \
- extern __typeof (name) aliasname __attribute__ ((alias (#name), \
- visibility ("hidden")));
-# define INTDEF2(name, newname) strong_alias (name, newname##_internal)
-# define INTVARDEF2(name, newname) _INTVARDEF (name, newname##_internal)
+
+/* Used to disable stack protection in sensitive places, like ifunc
+ resolvers and early static TLS init. */
+#ifdef HAVE_CC_NO_STACK_PROTECTOR
+# define inhibit_stack_protector \
+ __attribute__ ((__optimize__ ("-fno-stack-protector")))
#else
-# define INTUSE(name) name
-# define INTDEF(name)
-# define INTVARDEF(name)
-# define INTDEF2(name, newname)
-# define INTVARDEF2(name, newname)
+# define inhibit_stack_protector
#endif
/* The following macros are used for PLT bypassing within libc.so
If the function should be internal to multiple objects, say ld.so and
libc.so, the best way is to use:
- #if !defined NOT_IN_libc || defined IS_IN_rtld
+ #if IS_IN (libc) || IS_IN (rtld)
hidden_proto (foo)
#endif
versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
libc_hidden_ver (__real_foo, foo) */
-#if defined SHARED && defined DO_VERSIONING && !defined NO_HIDDEN
+#if defined SHARED && !defined NO_HIDDEN
# ifndef __ASSEMBLER__
# define __hidden_proto_hiddenattr(attrs...) \
__attribute__ ((visibility ("hidden"), ##attrs))
# define hidden_proto(name, attrs...) \
- __hidden_proto (name, __GI_##name, ##attrs)
-# define __hidden_proto(name, internal, attrs...) \
- extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
+ __hidden_proto (name, , __GI_##name, ##attrs)
+# define hidden_tls_proto(name, attrs...) \
+ __hidden_proto (name, __thread, __GI_##name, ##attrs)
+# define __hidden_proto(name, thread, internal, attrs...) \
+ extern thread __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
__hidden_proto_hiddenattr (attrs);
# define __hidden_asmname(name) \
__hidden_asmname1 (__USER_LABEL_PREFIX__, name)
# define hidden_data_def(name) strong_data_alias (name, __GI_##name)
# define hidden_data_weak(name) hidden_data_def (name)
# define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name)
-# ifdef HAVE_ASM_GLOBAL_DOT_NAME
-# define HIDDEN_JUMPTARGET(name) .__GI_##name
-# else
-# define HIDDEN_JUMPTARGET(name) __GI_##name
-# endif
+# define HIDDEN_JUMPTARGET(name) __GI_##name
# endif
#else
# ifndef __ASSEMBLER__
# define hidden_proto(name, attrs...)
+# define hidden_tls_proto(name, attrs...)
# else
# define HIDDEN_JUMPTARGET(name) JUMPTARGET(name)
# endif /* Not __ASSEMBLER__ */
# define hidden_data_weak(name)
# define hidden_data_def(name)
# define hidden_data_ver(local, name)
+# define hidden_nolink(name, lib, version)
#endif
-#if !defined NOT_IN_libc
+#if IS_IN (libc)
# define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libc_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
# define libc_hidden_def(name) hidden_def (name)
# define libc_hidden_weak(name) hidden_weak (name)
-# define libc_hidden_nolink(name, version) hidden_nolink (name, libc, version)
+# ifdef LINK_OBSOLETE_RPC
+ /* libc_hidden_nolink_sunrpc should only get used in sunrpc code. */
+# define libc_hidden_nolink_sunrpc(name, version) hidden_def (name)
+# else
+# define libc_hidden_nolink_sunrpc(name, version) hidden_nolink (name, libc, version)
+# endif
# define libc_hidden_ver(local, name) hidden_ver (local, name)
# define libc_hidden_data_def(name) hidden_data_def (name)
# define libc_hidden_data_weak(name) hidden_data_weak (name)
# define libc_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define libc_hidden_proto(name, attrs...)
+# define libc_hidden_tls_proto(name, attrs...)
# define libc_hidden_def(name)
# define libc_hidden_weak(name)
# define libc_hidden_ver(local, name)
# define libc_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_rtld
+#if IS_IN (rtld)
# define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define rtld_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
# define rtld_hidden_def(name) hidden_def (name)
# define rtld_hidden_weak(name) hidden_weak (name)
# define rtld_hidden_ver(local, name) hidden_ver (local, name)
# define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define rtld_hidden_proto(name, attrs...)
+# define rtld_hidden_tls_proto(name, attrs...)
# define rtld_hidden_def(name)
# define rtld_hidden_weak(name)
# define rtld_hidden_ver(local, name)
# define rtld_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_libm
+#if IS_IN (libm)
# define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libm_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
# define libm_hidden_def(name) hidden_def (name)
# define libm_hidden_weak(name) hidden_weak (name)
# define libm_hidden_ver(local, name) hidden_ver (local, name)
# define libm_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define libm_hidden_proto(name, attrs...)
+# define libm_hidden_tls_proto(name, attrs...)
# define libm_hidden_def(name)
# define libm_hidden_weak(name)
# define libm_hidden_ver(local, name)
# define libm_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_libresolv
+#if IS_IN (libmvec)
+# define libmvec_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libmvec_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
+# define libmvec_hidden_def(name) hidden_def (name)
+# define libmvec_hidden_weak(name) hidden_weak (name)
+# define libmvec_hidden_ver(local, name) hidden_ver (local, name)
+# define libmvec_hidden_data_def(name) hidden_data_def (name)
+# define libmvec_hidden_data_weak(name) hidden_data_weak (name)
+# define libmvec_hidden_data_ver(local, name) hidden_data_ver (local, name)
+#else
+# define libmvec_hidden_proto(name, attrs...)
+# define libmvec_hidden_tls_proto(name, attrs...)
+# define libmvec_hidden_def(name)
+# define libmvec_hidden_weak(name)
+# define libmvec_hidden_ver(local, name)
+# define libmvec_hidden_data_def(name)
+# define libmvec_hidden_data_weak(name)
+# define libmvec_hidden_data_ver(local, name)
+#endif
+
+#if IS_IN (libresolv)
# define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libresolv_hidden_tls_proto(name, attrs...) \
+ hidden_tls_proto (name, ##attrs)
# define libresolv_hidden_def(name) hidden_def (name)
# define libresolv_hidden_weak(name) hidden_weak (name)
# define libresolv_hidden_ver(local, name) hidden_ver (local, name)
# define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define libresolv_hidden_proto(name, attrs...)
+# define libresolv_hidden_tls_proto(name, attrs...)
# define libresolv_hidden_def(name)
# define libresolv_hidden_weak(name)
# define libresolv_hidden_ver(local, name)
# define libresolv_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_librt
+#if IS_IN (librt)
# define librt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define librt_hidden_tls_proto(name, attrs...) \
+ hidden_tls_proto (name, ##attrs)
# define librt_hidden_def(name) hidden_def (name)
# define librt_hidden_weak(name) hidden_weak (name)
# define librt_hidden_ver(local, name) hidden_ver (local, name)
# define librt_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define librt_hidden_proto(name, attrs...)
+# define librt_hidden_tls_proto(name, attrs...)
# define librt_hidden_def(name)
# define librt_hidden_weak(name)
# define librt_hidden_ver(local, name)
# define librt_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_libdl
+#if IS_IN (libdl)
# define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libdl_hidden_tls_proto(name, attrs...) \
+ hidden_tls_proto (name, ##attrs)
# define libdl_hidden_def(name) hidden_def (name)
# define libdl_hidden_weak(name) hidden_weak (name)
# define libdl_hidden_ver(local, name) hidden_ver (local, name)
# define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define libdl_hidden_proto(name, attrs...)
+# define libdl_hidden_tls_proto(name, attrs...)
# define libdl_hidden_def(name)
# define libdl_hidden_weak(name)
# define libdl_hidden_ver(local, name)
# define libdl_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_libnss_files
+#if IS_IN (libnss_files)
# define libnss_files_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libnss_files_hidden_tls_proto(name, attrs...) \
+ hidden_tls_proto (name, ##attrs)
# define libnss_files_hidden_def(name) hidden_def (name)
# define libnss_files_hidden_weak(name) hidden_weak (name)
# define libnss_files_hidden_ver(local, name) hidden_ver (local, name)
# define libnss_files_hidden_data_ver(local, name) hidden_data_ver(local, name)
#else
# define libnss_files_hidden_proto(name, attrs...)
+# define libnss_files_hidden_tls_proto(name, attrs...)
# define libnss_files_hidden_def(name)
# define libnss_files_hidden_weak(name)
# define libnss_files_hidden_ver(local, name)
# define libnss_files_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_libnsl
+#if IS_IN (libnsl)
# define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libnsl_hidden_tls_proto(name, attrs...) \
+ hidden_tls_proto (name, ##attrs)
+# ifdef LINK_OBSOLETE_NSL
+ /* libnsl_hidden_nolink should only get used in libnsl code. */
+# define libnsl_hidden_nolink_def(name, version) libnsl_hidden_def (name)
+# else
+# define libnsl_hidden_nolink_def(name, version) hidden_nolink (name, libnsl, version)
+# endif
# define libnsl_hidden_def(name) hidden_def (name)
# define libnsl_hidden_weak(name) hidden_weak (name)
# define libnsl_hidden_ver(local, name) hidden_ver (local, name)
# define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define libnsl_hidden_proto(name, attrs...)
+# define libnsl_hidden_tls_proto(name, attrs...)
# define libnsl_hidden_def(name)
# define libnsl_hidden_weak(name)
# define libnsl_hidden_ver(local, name)
# define libnsl_hidden_data_ver(local, name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_libnss_nisplus
+#if IS_IN (libnss_nisplus)
# define libnss_nisplus_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libnss_nisplus_hidden_tls_proto(name, attrs...) \
+ hidden_tls_proto (name, ##attrs)
# define libnss_nisplus_hidden_def(name) hidden_def (name)
# define libnss_nisplus_hidden_weak(name) hidden_weak (name)
# define libnss_nisplus_hidden_ver(local, name) hidden_ver (local, name)
# define libnss_nisplus_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define libnss_nisplus_hidden_proto(name, attrs...)
+# define libnss_nisplus_hidden_tls_proto(name, attrs...)
# define libnss_nisplus_hidden_def(name)
# define libnss_nisplus_hidden_weak(name)
# define libnss_nisplus_hidden_ver(local, name)
# define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
#endif
-#if defined NOT_IN_libc && defined IS_IN_libutil
+#if IS_IN (libutil)
# define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
+# define libutil_hidden_tls_proto(name, attrs...) \
+ hidden_tls_proto (name, ##attrs)
# define libutil_hidden_def(name) hidden_def (name)
# define libutil_hidden_weak(name) hidden_weak (name)
# define libutil_hidden_ver(local, name) hidden_ver (local, name)
# define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name)
#else
# define libutil_hidden_proto(name, attrs...)
+# define libutil_hidden_tls_proto(name, attrs...)
# define libutil_hidden_def(name)
# define libutil_hidden_weak(name)
# define libutil_hidden_ver(local, name)
# define compat_data_section .section ".data.compat", "aw";
#endif
-/* Marker used for indirection function symbols. */
-#define libc_ifunc(name, expr) \
- extern void *name##_ifunc (void) __asm__ (#name); \
- void *name##_ifunc (void) \
+/* Helper / base macros for indirect function symbols. */
+#define __ifunc_resolver(type_name, name, expr, arg, init, classifier) \
+ classifier inhibit_stack_protector void *name##_ifunc (arg) \
{ \
- INIT_ARCH (); \
- __typeof (name) *res = expr; \
+ init (); \
+ __typeof (type_name) *res = expr; \
return res; \
- } \
- __asm__ (".type " #name ", %gnu_indirect_function");
+ }
+
+#ifdef HAVE_GCC_IFUNC
+# define __ifunc(type_name, name, expr, arg, init) \
+ extern __typeof (type_name) name __attribute__ \
+ ((ifunc (#name "_ifunc"))); \
+ __ifunc_resolver (type_name, name, expr, arg, init, static)
+
+# define __ifunc_hidden(type_name, name, expr, arg, init) \
+ __ifunc (type_name, name, expr, arg, init)
+#else
+/* Gcc does not support __attribute__ ((ifunc (...))). Use the old behaviour
+ as fallback. But keep in mind that the debug information for the ifunc
+ resolver functions is not correct. It contains the ifunc'ed function as
+ DW_AT_linkage_name. E.g. lldb uses this field and an inferior function
+ call of the ifunc'ed function will fail due to "no matching function for
+ call to ..." because the ifunc'ed function and the resolver function have
+ different signatures. (Gcc support is disabled at least on a ppc64le
+ Ubuntu 14.04 system.) */
+
+# define __ifunc(type_name, name, expr, arg, init) \
+ extern __typeof (type_name) name; \
+ void *name##_ifunc (arg) __asm__ (#name); \
+ __ifunc_resolver (type_name, name, expr, arg, init,) \
+ __asm__ (".type " #name ", %gnu_indirect_function");
+
+# define __ifunc_hidden(type_name, name, expr, arg, init) \
+ extern __typeof (type_name) __libc_##name; \
+ __ifunc (type_name, __libc_##name, expr, arg, init) \
+ strong_alias (__libc_##name, name);
+#endif /* !HAVE_GCC_IFUNC */
+
+/* The following macros are used for indirect function symbols in libc.so.
+ First of all, you need to have the function prototyped somewhere,
+ say in foo.h:
+
+ int foo (int __bar);
+
+ If you have an implementation for foo which e.g. uses a special hardware
+ feature which isn't available on all machines where this libc.so will be
+ used but decideable if available at runtime e.g. via hwcaps, you can provide
+ two or multiple implementations of foo:
+
+ int __foo_default (int __bar)
+ {
+ return __bar;
+ }
+
+ int __foo_special (int __bar)
+ {
+ return __bar;
+ }
+
+ If your function foo has no libc_hidden_proto (foo) defined for PLT
+ bypassing, you can use:
+
+ #define INIT_ARCH() unsigned long int hwcap = __GLRO(dl_hwcap);
+
+ libc_ifunc (foo, (hwcap & HWCAP_SPECIAL) ? __foo_special : __foo_default);
+
+ This will define a resolver function for foo which returns __foo_special or
+ __foo_default depending on your specified expression. Please note that you
+ have to define a macro function INIT_ARCH before using libc_ifunc macro as
+ it is called by the resolver function before evaluating the specified
+ expression. In this example it is used to prepare the hwcap variable.
+ The resolver function is assigned to an ifunc'ed symbol foo. Calls to foo
+ from inside or outside of libc.so will be indirected by a PLT call.
+
+ If your function foo has a libc_hidden_proto (foo) defined for PLT bypassing
+ and calls to foo within libc.so should always go to one specific
+ implementation of foo e.g. __foo_default then you have to add:
+
+ __hidden_ver1 (__foo_default, __GI_foo, __foo_default);
+
+ or a tweaked definition of libc_hidden_def macro after the __foo_default
+ function definition. Calls to foo within libc.so will always go directly to
+ __foo_default. Calls to foo from outside libc.so will be indirected by a
+ PLT call to ifunc'ed symbol foo which you have to define in a separate
+ compile unit:
+
+ #define foo __redirect_foo
+ #include <foo.h>
+ #undef foo
+
+ extern __typeof (__redirect_foo) __foo_default attribute_hidden;
+ extern __typeof (__redirect_foo) __foo_special attribute_hidden;
+
+ libc_ifunc_redirected (__redirect_foo, foo,
+ (hwcap & HWCAP_SPECIAL)
+ ? __foo_special
+ : __foo_default);
+
+ This will define the ifunc'ed symbol foo like above. The redirection of foo
+ in header file is needed to omit an additional defintion of __GI_foo which
+ would end in a linker error while linking libc.so. You have to specify
+ __redirect_foo as first parameter which is used within libc_ifunc_redirected
+ macro in conjunction with typeof to define the ifunc'ed symbol foo.
+
+ If your function foo has a libc_hidden_proto (foo) defined and calls to foo
+ within or from outside libc.so should go via ifunc'ed symbol, then you have
+ to use:
+
+ libc_ifunc_hidden (foo, foo,
+ (hwcap & HWCAP_SPECIAL)
+ ? __foo_special
+ : __foo_default);
+ libc_hidden_def (foo)
+
+ The first parameter foo of libc_ifunc_hidden macro is used in the same way
+ as for libc_ifunc_redirected macro. */
+
+#define libc_ifunc(name, expr) __ifunc (name, name, expr, void, INIT_ARCH)
+
+#define libc_ifunc_redirected(redirected_name, name, expr) \
+ __ifunc (redirected_name, name, expr, void, INIT_ARCH)
+
+#define libc_ifunc_hidden(redirected_name, name, expr) \
+ __ifunc_hidden (redirected_name, name, expr, void, INIT_ARCH)
/* The body of the function is supposed to use __get_cpu_features
which will, if necessary, initialize the data first. */
-#define libm_ifunc(name, expr) \
- extern void *name##_ifunc (void) __asm__ (#name); \
- void *name##_ifunc (void) \
- { \
- __typeof (name) *res = expr; \
- return res; \
- } \
- __asm__ (".type " #name ", %gnu_indirect_function");
-
-#ifdef HAVE_ASM_SET_DIRECTIVE
-# define libc_ifunc_hidden_def1(local, name) \
- __asm__ (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE) \
- " " #local "\n\t" \
- ".hidden " #local "\n\t" \
- ".set " #local ", " #name);
+#define libm_ifunc_init()
+#define libm_ifunc(name, expr) \
+ __ifunc (name, name, expr, void, libm_ifunc_init)
+
+/* Add the compiler optimization to inhibit loop transformation to library
+ calls. This is used to avoid recursive calls in memset and memmove
+ default implementations. */
+#ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
+# define inhibit_loop_to_libcall \
+ __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
#else
-# define libc_ifunc_hidden_def1(local, name) \
- __asm__ (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE) \
- " " #local "\n\t" \
- ".hidden " #local "\n\t" \
- #local " = " #name);
+# define inhibit_loop_to_libcall
#endif
+\f
+/* These macros facilitate sharing source files with gnulib.
+
+ They are here instead of sys/cdefs.h because they should not be
+ used in public header files.
+
+ Their definitions should be kept consistent with the definitions in
+ gnulib-common.m4, but it is not necessary to cater to old non-GCC
+ compilers, since they will only be used while building glibc itself.
+ (Note that _GNUC_PREREQ cannot be used in this file.) */
-#define libc_ifunc_hidden_def(name) \
- libc_ifunc_hidden_def1 (__GI_##name, name)
+/* Define as a marker that can be attached to declarations that might not
+ be used. This helps to reduce warnings, such as from
+ GCC -Wunused-parameter. */
+#if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+# define _GL_UNUSED __attribute__ ((__unused__))
+#else
+# define _GL_UNUSED
+#endif
+
+/* gcc supports the "unused" attribute on possibly unused labels, and
+ g++ has since version 4.5. Note to support C++ as well as C,
+ _GL_UNUSED_LABEL should be used with a trailing ; */
+#if !defined __cplusplus || __GNUC__ > 4 \
+ || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
+# define _GL_UNUSED_LABEL _GL_UNUSED
+#else
+# define _GL_UNUSED_LABEL
+#endif
+
+/* The __pure__ attribute was added in gcc 2.96. */
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
+# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+#else
+# define _GL_ATTRIBUTE_PURE /* empty */
+#endif
+
+/* The __const__ attribute was added in gcc 2.95. */
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95)
+# define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
+#else
+# define _GL_ATTRIBUTE_CONST /* empty */
+#endif
+#endif /* !_ISOMAC */
#endif /* libc-symbols.h */
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