glibc/config.h.in
Fangrui Song cd6ae7ea54 Set the retain attribute on _elf_set_element if CC supports [BZ #27492]
So that text_set_element/data_set_element/bss_set_element defined
variables will be retained by the linker.

Note: 'used' and 'retain' are orthogonal: 'used' makes sure the variable
will not be optimized out; 'retain' prevents section garbage collection
if the linker support SHF_GNU_RETAIN.

GNU ld 2.37 and LLD 13 will support -z start-stop-gc which allow C
identifier name sections to be GCed even if there are live
__start_/__stop_ references.

Without the change, there are some static linking problems, e.g.
_IO_cleanup (libio/genops.c) may be discarded by ld --gc-sections, so
stdout is not flushed on exit.

Note: GCC may warning 'retain' attribute ignored while __has_attribute(retain)
is 1 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99587).

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-04-16 11:26:39 -07:00

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/* Define if building with SELinux support. Set by --with-selinux. */
#undef HAVE_SELINUX
/* Defined if building with SELinux support & audit libs are detected. */
#undef HAVE_LIBAUDIT
/* Defined if building with SELinux support & libcap libs are detected. */
#undef HAVE_LIBCAP
/* Define to the assembler line separator character for multiple
assembler instructions per line. Default is `;' */
#undef ASM_LINE_SEP
/* Define if __attribute__((section("foo"))) puts quotes around foo. */
#undef HAVE_SECTION_QUOTES
/* Define if the assembler supports the `.set' directive. */
#undef HAVE_ASM_SET_DIRECTIVE
/* On powerpc64, use overlapping .opd entries. */
#undef USE_PPC64_OVERLAPPING_OPD
/* On powerpc64, use @notoc. */
#undef USE_PPC64_NOTOC
/* Define if _Unwind_Find_FDE should be exported from glibc. */
#undef EXPORT_UNWIND_FIND_FDE
/* Define if static NSS modules are wanted. */
#undef DO_STATIC_NSS
/* Assume that the compiler supports __builtin_expect.
This macro is necessary for proper compilation of code
shared between GNU libc and GNU gettext projects. */
#define HAVE_BUILTIN_EXPECT 1
/* Define if the compiler supports __builtin_memset. */
#undef HAVE_BUILTIN_MEMSET
/* Define if compiler accepts -ftree-loop-distribute-patterns. */
#undef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
/* Define if compiler accepts -fno-stack-protector in an
__attribute__ ((__optimize__)). */
#undef HAVE_CC_NO_STACK_PROTECTOR
/* The level of stack protection in use for glibc as a whole.
May be overridden on a file-by-file basis. */
#ifndef STACK_PROTECTOR_LEVEL
#undef STACK_PROTECTOR_LEVEL
#endif
/* Define if the linker supports the -z combreloc option. */
#undef HAVE_Z_COMBRELOC
/* Define if _rtld_local structure should be forced into .sdata section. */
#undef HAVE_SDATA_SECTION
/* Define if compiler supports AVX512. */
#undef HAVE_AVX512_SUPPORT
/* Define if assembler supports AVX512DQ. */
#undef HAVE_AVX512DQ_ASM_SUPPORT
/* Define if assembler supports z10 zarch instructions as default on S390. */
#undef HAVE_S390_MIN_Z10_ZARCH_ASM_SUPPORT
/* Define if assembler supports z196 zarch instructions as default on S390. */
#undef HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT
/* Define if assembler supports z13 zarch instructions as default on S390. */
#undef HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
/* Define if assembler supports arch13 zarch instruction as default on S390. */
#undef HAVE_S390_MIN_ARCH13_ZARCH_ASM_SUPPORT
/* Define if assembler supports vector instructions on S390. */
#undef HAVE_S390_VX_ASM_SUPPORT
/* Define if gcc supports vector registers as clobbers in inline assembly
on S390. */
#undef HAVE_S390_VX_GCC_SUPPORT
/* Define if assembler supports arch13 instructions on S390. */
#undef HAVE_S390_ARCH13_ASM_SUPPORT
/* Define if assembler supports Intel MPX. */
#undef HAVE_MPX_SUPPORT
/* Define if the compiler\'s exception support is based on libunwind. */
#undef HAVE_CC_WITH_LIBUNWIND
/* Define if the access to static and hidden variables is position independent
and does not need relocations. */
#undef PI_STATIC_AND_HIDDEN
/* Define this to disable the 'hidden_proto' et al macros in
include/libc-symbols.h that avoid PLT slots in PIE. */
#undef NO_HIDDEN_EXTERN_FUNC_IN_PIE
/* Define this to disable the 'hidden_proto' et al macros in
include/libc-symbols.h that avoid PLT slots in the shared objects. */
#undef NO_HIDDEN
/* Define this to disable in rtld the 'hidden_proto' et al macros in
include/libc-symbols.h that avoid PLT slots in the shared objects. */
#undef NO_RTLD_HIDDEN
/* Define this to disable lazy relocations in DSOs. */
#undef BIND_NOW
/* AArch64 big endian ABI */
#undef HAVE_AARCH64_BE
/* AArch64 BTI support enabled. */
#define HAVE_AARCH64_BTI 0
/* AArch64 PAC-RET code generation is enabled. */
#define HAVE_AARCH64_PAC_RET 0
/* ARC big endian ABI */
#undef HAVE_ARC_BE
/* C-SKY ABI version. */
#undef CSKYABI
/* C-SKY floating-point ABI. */
#undef CSKY_HARD_FLOAT
/* RISC-V integer ABI for ld.so. */
#undef RISCV_ABI_XLEN
/* RISC-V floating-point ABI for ld.so. */
#undef RISCV_ABI_FLEN
/* Linux specific: minimum supported kernel version. */
#undef __LINUX_KERNEL_VERSION
/* Override abi-tags ABI version if necessary. */
#undef __ABI_TAG_VERSION
/* Mach/Hurd specific: define if mig supports the `retcode' keyword. */
#undef HAVE_MIG_RETCODE
/* Mach specific: define if the `host_page_size' RPC is available. */
#undef HAVE_HOST_PAGE_SIZE
/* Mach/i386 specific: define if the `i386_io_perm_*' RPCs are available. */
#undef HAVE_I386_IO_PERM_MODIFY
/* Mach/i386 specific: define if the `i386_set_gdt' RPC is available. */
#undef HAVE_I386_SET_GDT
/* Define if inlined system calls are available. */
#undef HAVE_INLINED_SYSCALLS
/* Define if your compiler defaults to -msecure-plt mode on ppc. */
#undef HAVE_PPC_SECURE_PLT
/* Define if __stack_chk_guard canary should be randomized at program startup. */
#undef ENABLE_STACKGUARD_RANDOMIZE
/* Define if memory tagging support should be enabled. */
#undef USE_MTAG
/* Package description. */
#undef PKGVERSION
/* Bug reporting address. */
#undef REPORT_BUGS_TO
/* Define if multi-arch DSOs should be generated. */
#undef USE_MULTIARCH
/* Define if Systemtap <sys/sdt.h> probes should be defined. */
#undef USE_STAP_PROBE
/* Define if library functions should try to contact the nscd daemon. */
#undef USE_NSCD
/* Define if the dynamic linker should consult an ld.so.cache file. */
#undef USE_LDCONFIG
/* Define to 1 if STT_GNU_IFUNC support actually works. */
#define HAVE_IFUNC 0
/* Define if gcc supports attribute ifunc. */
#undef HAVE_GCC_IFUNC
/* Define if CC supports attribute retain. */
#undef HAVE_GNU_RETAIN
/* Define if the linker defines __ehdr_start. */
#undef HAVE_EHDR_START
/* Define to 1 if the assembler needs intermediate aliases to define
multiple symbol versions for one symbol. */
#define SYMVER_NEEDS_ALIAS 0
/*
*/
#ifndef _LIBC
/* These symbols might be defined by some sysdeps configures.
They are used only in miscellaneous generator programs, not
in compiling libc itself. */
/* sysdeps/generic/configure.ac */
#undef HAVE_PSIGNAL
/* sysdeps/unix/configure.ac */
#undef HAVE_STRERROR
/* sysdeps/unix/common/configure.ac */
#undef HAVE_SYS_SIGLIST
#undef HAVE__SYS_SIGLIST
#undef HAVE__CTYPE_
#undef HAVE___CTYPE_
#undef HAVE___CTYPE
#undef HAVE__CTYPE__
#undef HAVE__CTYPE
#undef HAVE__LOCP
#endif
/*
*/
#ifdef _LIBC
/* The zic and zdump programs need these definitions. */
#define HAVE_STRERROR 1
/* The locale code needs these definitions. */
#define HAVE_REGEX 1
/* The ARM hard-float ABI is being used. */
#undef HAVE_ARM_PCS_VFP
/* The ARM movw/movt instructions using PC-relative relocs work right. */
#define ARM_PCREL_MOVW_OK 0
/* The pt_chown binary is being built and used by grantpt. */
#define HAVE_PT_CHOWN 0
/* Define if the compiler supports __builtin_trap without
any external dependencies such as making a function call. */
#define HAVE_BUILTIN_TRAP 0
/* ports/sysdeps/mips/configure.in */
/* Define if using the IEEE 754-2008 NaN encoding on the MIPS target. */
#undef HAVE_MIPS_NAN2008
/* The PowerPC64 ELFv2 ABI is being used. */
#undef HAVE_ELFV2_ABI
/* PowerPC32 uses fcfid for integer to floating point conversions. */
#define HAVE_PPC_FCFID 0
/* PowerPC32 uses fctidz for floating point to long long conversions. */
#define HAVE_PPC_FCTIDZ 0
/* Build glibc with tunables support. */
#define HAVE_TUNABLES 0
/* Define if static PIE is supported. */
#undef SUPPORT_STATIC_PIE
/* Define if static PIE is enabled. */
#define ENABLE_STATIC_PIE 0
/* Some compiler options may now allow to use ebp in __asm__ (used mainly
in i386 6 argument syscall issue). */
#define CAN_USE_REGISTER_ASM_EBP 0
/* The default value of x86 CET control. */
#define DEFAULT_DL_X86_CET_CONTROL cet_elf_property
/* Define if x86 ISA level should be included in shared libraries. */
#undef INCLUDE_X86_ISA_LEVEL
/* Define if -msahf is enabled by default on x86. */
#undef HAVE_X86_LAHF_SAHF
/* Define if -mmovbe is enabled by default on x86. */
#undef HAVE_X86_MOVBE
#endif