| /* Support macros for making weak and strong aliases for symbols, |
| and for using symbol sets and linker warnings with GNU ld. |
| Copyright (C) 1995-2018 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 Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #ifndef _LIBC_SYMBOLS_H |
| #define _LIBC_SYMBOLS_H 1 |
| |
| /* This file is included implicitly in the compilation of every source file, |
| using -include. It includes config.h. */ |
| |
| /* 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 |
| |
| #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, |
| 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 |
| |
| /* Some files must be compiled with optimization on. */ |
| /* This is a nuisance while experimenting; re-enable when done. */ |
| #if 0 |
| #if !defined __ASSEMBLER__ && !defined __OPTIMIZE__ |
| # error "glibc cannot be compiled without optimization" |
| #endif |
| #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> |
| |
| /* When PIC is defined and SHARED isn't defined, we are building PIE |
| by default. */ |
| #if defined PIC && !defined SHARED |
| # define BUILD_PIE_DEFAULT 1 |
| #else |
| # define BUILD_PIE_DEFAULT 0 |
| #endif |
| |
| /* 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 |
| |
| /* The symbols in all the user (non-_) macros are C symbols. */ |
| |
| #ifndef __SYMBOL_PREFIX |
| # define __SYMBOL_PREFIX |
| #endif |
| |
| #ifndef C_SYMBOL_NAME |
| # define C_SYMBOL_NAME(name) name |
| #endif |
| |
| #ifndef ASM_LINE_SEP |
| # define ASM_LINE_SEP ; |
| #endif |
| |
| #ifndef __ASSEMBLER__ |
| /* GCC understands weak symbols and aliases; use its interface where |
| possible, instead of embedded assembly language. */ |
| |
| /* Define ALIASNAME as a strong alias for NAME. */ |
| # define strong_alias(name, aliasname) _strong_alias(name, aliasname) |
| # define _strong_alias(name, aliasname) \ |
| extern __typeof (name) aliasname __attribute__ ((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__)) |
| |
| /* Define ALIASNAME as a weak alias for NAME. |
| If weak aliases are not available, this defines a strong alias. */ |
| # define weak_alias(name, aliasname) _weak_alias (name, aliasname) |
| # define _weak_alias(name, aliasname) \ |
| extern __typeof (name) aliasname __attribute__ ((weak, alias (#name))); |
| |
| /* Same as WEAK_ALIAS, but mark symbol as hidden. */ |
| # define weak_hidden_alias(name, aliasname) \ |
| _weak_hidden_alias (name, aliasname) |
| # define _weak_hidden_alias(name, aliasname) \ |
| extern __typeof (name) aliasname \ |
| __attribute__ ((weak, alias (#name), __visibility__ ("hidden"))); |
| |
| /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined). */ |
| # 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 |
| # define strong_alias(original, alias) \ |
| .globl 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) |
| # else |
| # 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 weak_alias(original, alias) \ |
| .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP \ |
| C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) |
| |
| # define weak_extern(symbol) \ |
| .weak C_SYMBOL_NAME (symbol) |
| |
| #endif /* __ASSEMBLER__ */ |
| |
| /* Determine the return address. */ |
| #define RETURN_ADDRESS(nr) \ |
| __builtin_extract_return_addr (__builtin_return_address (nr)) |
| |
| /* 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. */ |
| #define __make_section_unallocated(section_string) \ |
| asm (".section " section_string "\n\t.previous"); |
| |
| /* 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. */ |
| /* Clang sees newline and helpfully adds additional quotes; disable that. */ |
| #if defined(__clang__) |
| # define __sec_comment |
| #else |
| #ifdef HAVE_SECTION_QUOTES |
| # define __sec_comment "\"\n\t#\"" |
| #else |
| # define __sec_comment "\n\t#" |
| #endif |
| #endif |
| #define link_warning(symbol, msg) \ |
| __make_section_unallocated (".gnu.warning." #symbol) \ |
| static const char __evoke_link_warning_##symbol[] \ |
| __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \ |
| = msg; |
| #define libc_freeres_ptr(decl) \ |
| __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \ |
| decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment))) |
| #define __libc_freeres_fn_section \ |
| __attribute__ ((section ("__libc_freeres_fn"))) |
| |
| #define libc_freeres_fn(name) \ |
| static void name (void) __attribute_used__ __libc_freeres_fn_section; \ |
| text_set_element (__libc_subfreeres, name); \ |
| static void name (void) |
| |
| /* A canned warning for sysdeps/stub functions. */ |
| #define stub_warning(name) \ |
| __make_section_unallocated (".gnu.glibc-stub." #name) \ |
| link_warning (name, #name " is not implemented and will always fail") |
| |
| /* Warning for linking functions calling dlopen into static binaries. */ |
| #ifdef SHARED |
| #define static_link_warning(name) |
| #else |
| #define static_link_warning(name) static_link_warning1(name) |
| #define static_link_warning1(name) \ |
| link_warning(name, "Using '" #name "' in statically linked applications \ |
| requires at runtime the shared libraries from the glibc version used \ |
| for linking") |
| #endif |
| |
| /* Declare SYMBOL to be TYPE (`function' or `object') of SIZE bytes |
| alias to ORIGINAL, when the assembler supports such declarations |
| (such as in ELF). |
| This is only necessary when defining something in assembly, or playing |
| funny alias games where the size should be other than what the compiler |
| thinks it is. */ |
| #define declare_symbol_alias(symbol, original, type, size) \ |
| declare_symbol_alias_1 (symbol, original, type, size) |
| #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__ */ |
| |
| |
| /* |
| |
| */ |
| |
| #ifdef HAVE_GNU_RETAIN |
| # define attribute_used_retain __attribute__ ((__used__, __retain__)) |
| #else |
| # define attribute_used_retain __attribute__ ((__used__)) |
| #endif |
| |
| /* Symbol set support macros. */ |
| |
| /* 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 SHARED |
| /* 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_used_retain __attribute__ ((section (#set))) = &(symbol) |
| #else |
| # define _elf_set_element(set, symbol) \ |
| static const void *const __elf_set_##set##_element_##symbol##__ \ |
| attribute_used_retain __attribute__ ((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. |
| In a shared library, this is always local to that shared object. |
| For static linking, the set might be wholly absent and so we use |
| weak references. */ |
| #define symbol_set_declare(set) \ |
| extern char const __start_##set[] __symbol_set_attribute; \ |
| extern char const __stop_##set[] __symbol_set_attribute; |
| #ifdef SHARED |
| # define __symbol_set_attribute attribute_hidden |
| #else |
| # define __symbol_set_attribute __attribute__ ((weak)) |
| #endif |
| |
| /* Return a pointer (void *const *) to the first element of SET. */ |
| #define symbol_set_first_element(set) ((void *const *) (&__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) >= (void *const *) &__stop_##set) |
| |
| /* 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_reference(real, name, version) |
| # define default_symbol_version(real, name, version) \ |
| _default_symbol_version(real, name, version) |
| # ifdef __ASSEMBLER__ |
| # define _default_symbol_version(real, name, version) \ |
| .symver real, name##@##@##version |
| # else |
| # define _default_symbol_version(real, name, version) \ |
| __asm__ (".symver " #real "," #name "@@" #version) |
| # endif |
| #else |
| # define symbol_version(real, name, version) |
| # define default_symbol_version(real, name, version) \ |
| strong_alias(real, name) |
| #endif |
| |
| #if defined SHARED || defined LIBC_NONSHARED \ |
| || (BUILD_PIE_DEFAULT && IS_IN (libc)) |
| # define attribute_hidden __attribute__ ((visibility ("hidden"))) |
| #else |
| # define attribute_hidden |
| #endif |
| |
| #define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec"))) |
| |
| #define attribute_relro __attribute__ ((section (".data.rel.ro"))) |
| |
| |
| /* 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 inhibit_stack_protector |
| #endif |
| |
| /* The following macros are used for PLT bypassing within libc.so |
| (and if needed other libraries similarly). |
| First of all, you need to have the function prototyped somewhere, |
| say in foo/foo.h: |
| |
| int foo (int __bar); |
| |
| If calls to foo within libc.so should always go to foo defined in libc.so, |
| then in include/foo.h you add: |
| |
| libc_hidden_proto (foo) |
| |
| line and after the foo function definition: |
| |
| int foo (int __bar) |
| { |
| return __bar; |
| } |
| libc_hidden_def (foo) |
| |
| or |
| |
| int foo (int __bar) |
| { |
| return __bar; |
| } |
| libc_hidden_weak (foo) |
| |
| Similarly for global data. If references to foo within libc.so should |
| always go to foo defined in libc.so, then in include/foo.h you add: |
| |
| libc_hidden_proto (foo) |
| |
| line and after foo's definition: |
| |
| int foo = INITIAL_FOO_VALUE; |
| libc_hidden_data_def (foo) |
| |
| or |
| |
| int foo = INITIAL_FOO_VALUE; |
| libc_hidden_data_weak (foo) |
| |
| If foo is normally just an alias (strong or weak) to some other function, |
| you should use the normal strong_alias first, then add libc_hidden_def |
| or libc_hidden_weak: |
| |
| int baz (int __bar) |
| { |
| return __bar; |
| } |
| strong_alias (baz, foo) |
| libc_hidden_weak (foo) |
| |
| If the function should be internal to multiple objects, say ld.so and |
| libc.so, the best way is to use: |
| |
| #if IS_IN (libc) || IS_IN (rtld) |
| hidden_proto (foo) |
| #endif |
| |
| in include/foo.h and the normal macros at all function definitions |
| depending on what DSO they belong to. |
| |
| If versioned_symbol macro is used to define foo, |
| libc_hidden_ver macro should be used, as in: |
| |
| int __real_foo (int __bar) |
| { |
| return __bar; |
| } |
| versioned_symbol (libc, __real_foo, foo, GLIBC_2_1); |
| libc_hidden_ver (__real_foo, foo) */ |
| |
| #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_tls_proto(name, attrs...) \ |
| __hidden_proto (name, __thread, __GI_##name, ##attrs) |
| #ifndef __clang__ |
| # define __hidden_proto(name, thread, internal, attrs...) \ |
| extern thread __typeof (name) name __asm__ (__hidden_asmname (#internal)) \ |
| __hidden_proto_hiddenattr (attrs); |
| #else |
| # define __hidden_proto(name, thread, internal, attrs...) \ |
| extern thread __typeof (name) name \ |
| __hidden_proto_hiddenattr (attrs); \ |
| _Pragma (__redefine(name, internal)) |
| /* Note that this macro does not use __hidden_asmname, since it produces a string. */ |
| # define __redefine(name, internal) __stringize(redefine_extname name internal) |
| # define __stringize(X) #X |
| #endif |
| # define __hidden_asmname(name) \ |
| __hidden_asmname1 (__USER_LABEL_PREFIX__, name) |
| # define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name) |
| # define __hidden_asmname2(prefix, name) #prefix name |
| # define __hidden_ver1(local, internal, name) \ |
| extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \ |
| extern __typeof (name) __EI_##name \ |
| __attribute__((alias (__hidden_asmname (#local)))) |
| # define hidden_ver(local, name) __hidden_ver1(local, __GI_##name, name); |
| # define hidden_data_ver(local, name) hidden_ver(local, name) |
| # define hidden_def(name) __hidden_ver1(__GI_##name, name, name); |
| # define hidden_data_def(name) hidden_def(name) |
| # define hidden_weak(name) \ |
| __hidden_ver1(__GI_##name, name, name) __attribute__((weak)); |
| # define hidden_data_weak(name) hidden_weak(name) |
| # define hidden_nolink(name, lib, version) \ |
| __hidden_nolink1 (__GI_##name, __EI_##name, name, VERSION_##lib##_##version) |
| # define __hidden_nolink1(local, internal, name, version) \ |
| __hidden_nolink2 (local, internal, name, version) |
| # define __hidden_nolink2(local, internal, name, version) \ |
| extern __typeof (name) internal __attribute__ ((alias (#local))); \ |
| __hidden_nolink3 (local, internal, #name "@" #version) |
| # define __hidden_nolink3(local, internal, vername) \ |
| __asm__ (".symver " #internal ", " vername); |
| # else |
| /* For assembly, we need to do the opposite of what we do in C: |
| in assembly gcc __REDIRECT stuff is not in place, so functions |
| are defined by its normal name and we need to create the |
| __GI_* alias to it, in C __REDIRECT causes the function definition |
| to use __GI_* name and we need to add alias to the real name. |
| There is no reason to use hidden_weak over hidden_def in assembly, |
| but we provide it for consistency with the C usage. |
| hidden_proto doesn't make sense for assembly but the equivalent |
| is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET. */ |
| # define hidden_def(name) strong_alias (name, __GI_##name) |
| # define hidden_weak(name) hidden_def (name) |
| # define hidden_ver(local, name) strong_alias (local, __GI_##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) |
| # define HIDDEN_JUMPTARGET(name) __GI_##name |
| # endif |
| #else |
| # ifndef __ASSEMBLER__ |
| # if !defined SHARED && IS_IN (libc) && !defined LIBC_NONSHARED \ |
| && (!defined PIC || !defined NO_HIDDEN_EXTERN_FUNC_IN_PIE) \ |
| && !defined NO_HIDDEN |
| # define __hidden_proto_hiddenattr(attrs...) \ |
| __attribute__ ((visibility ("hidden"), ##attrs)) |
| # define hidden_proto(name, attrs...) \ |
| __hidden_proto (name, , name, ##attrs) |
| # define hidden_tls_proto(name, attrs...) \ |
| __hidden_proto (name, __thread, name, ##attrs) |
| # define __hidden_proto(name, thread, internal, attrs...) \ |
| extern thread __typeof (name) name __hidden_proto_hiddenattr (attrs); |
| # else |
| # define hidden_proto(name, attrs...) |
| # define hidden_tls_proto(name, attrs...) |
| # endif |
| # else |
| # define HIDDEN_JUMPTARGET(name) JUMPTARGET(name) |
| # endif /* Not __ASSEMBLER__ */ |
| # define hidden_weak(name) |
| # define hidden_def(name) |
| # define hidden_ver(local, name) |
| # define hidden_data_weak(name) |
| # define hidden_data_def(name) |
| # define hidden_data_ver(local, name) |
| # define hidden_nolink(name, lib, version) |
| #endif |
| |
| #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) |
| # 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_def(name) |
| # define libc_hidden_data_weak(name) |
| # define libc_hidden_data_ver(local, name) |
| #endif |
| |
| #if IS_IN (rtld) && !defined NO_RTLD_HIDDEN |
| # 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_def(name) hidden_data_def (name) |
| # define rtld_hidden_data_weak(name) hidden_data_weak (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_def(name) |
| # define rtld_hidden_data_weak(name) |
| # define rtld_hidden_data_ver(local, name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define libm_hidden_data_weak(name) hidden_data_weak (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_def(name) |
| # define libm_hidden_data_weak(name) |
| # define libm_hidden_data_ver(local, name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define libresolv_hidden_data_weak(name) hidden_data_weak (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_def(name) |
| # define libresolv_hidden_data_weak(name) |
| # define libresolv_hidden_data_ver(local, name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define librt_hidden_data_weak(name) hidden_data_weak (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_def(name) |
| # define librt_hidden_data_weak(name) |
| # define librt_hidden_data_ver(local, name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define libdl_hidden_data_weak(name) hidden_data_weak (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_def(name) |
| # define libdl_hidden_data_weak(name) |
| # define libdl_hidden_data_ver(local, name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define libnss_files_hidden_data_weak(name) hidden_data_weak (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_def(name) |
| # define libnss_files_hidden_data_weak(name) |
| # define libnss_files_hidden_data_ver(local, name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define libnsl_hidden_data_weak(name) hidden_data_weak (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_def(name) |
| # define libnsl_hidden_data_weak(name) |
| # define libnsl_hidden_data_ver(local, name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define libnss_nisplus_hidden_data_weak(name) hidden_data_weak (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 libnss_nisplus_hidden_data_def(name) |
| # define libnss_nisplus_hidden_data_weak(name) |
| # define libnss_nisplus_hidden_data_ver(local, name) |
| #endif |
| |
| #define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs) |
| #define libc_hidden_builtin_def(name) libc_hidden_def (name) |
| #define libc_hidden_builtin_weak(name) libc_hidden_weak (name) |
| #define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name) |
| #ifdef __ASSEMBLER__ |
| # define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name) |
| #endif |
| |
| #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_def(name) hidden_data_def (name) |
| # define libutil_hidden_data_weak(name) hidden_data_weak (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 libutil_hidden_data_def(name) |
| # define libutil_hidden_data_weak(name) |
| # define libutil_hidden_data_ver(local, name) |
| #endif |
| |
| /* Get some dirty hacks. */ |
| #include <symbol-hacks.h> |
| |
| /* Move compatibility symbols out of the way by placing them all in a |
| special section. */ |
| #ifndef __ASSEMBLER__ |
| # define attribute_compat_text_section \ |
| __attribute__ ((section (".text.compat"))) |
| # define attribute_compat_data_section \ |
| __attribute__ ((section (".data.compat"))) |
| #else |
| # define compat_text_section .section ".text.compat", "ax"; |
| # define compat_data_section .section ".data.compat", "aw"; |
| #endif |
| |
| /* Helper / base macros for indirect function symbols. */ |
| #define __ifunc_resolver(type_name, name, expr, arg, init, classifier) \ |
| classifier inhibit_stack_protector \ |
| __typeof (type_name) *name##_ifunc (arg) \ |
| { \ |
| init (); \ |
| __typeof (type_name) *res = expr; \ |
| return res; \ |
| } |
| |
| #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; \ |
| __typeof (type_name) *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_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 inhibit_loop_to_libcall |
| #endif |
| |
| /* 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 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 */ |