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6901def689
When --enable-bind-now is used to configure glibc build, we can avoid an extra branch to the PLT entry by using indirect branch via the GOT slot instead, which is similar to the first instructuon in the PLT entry. Changes in the shared library sizes in text sections: Shared library Before (bytes) After (bytes) libm.so 1060813 1060797 libmvec.so 160881 160805 libpthread.so 94992 94984 librt.so 25064 25048 * config.h.in (BIND_NOW): New. * configure.ac (BIND_NOW): New. Defined for --enable-bind-now. * configure: Regenerated. * sysdeps/x86_64/sysdep.h (JUMPTARGET)[BIND_NOW]: Defined to indirect branch via the GOT slot.
169 lines
4.8 KiB
C
169 lines
4.8 KiB
C
/* Assembler macros for x86-64.
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Copyright (C) 2001-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _X86_64_SYSDEP_H
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#define _X86_64_SYSDEP_H 1
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#include <sysdeps/generic/sysdep.h>
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#ifdef __ASSEMBLER__
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/* Syntactic details of assembler. */
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/* This macro is for setting proper CFI with DW_CFA_expression describing
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the register as saved relative to %rsp instead of relative to the CFA.
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Expression is DW_OP_drop, DW_OP_breg7 (%rsp is register 7), sleb128 offset
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from %rsp. */
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#define cfi_offset_rel_rsp(regn, off) .cfi_escape 0x10, regn, 0x4, 0x13, \
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0x77, off & 0x7F | 0x80, off >> 7
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/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
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#define ALIGNARG(log2) 1<<log2
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#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
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/* Define an entry point visible from C. */
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#define ENTRY(name) \
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.globl C_SYMBOL_NAME(name); \
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.type C_SYMBOL_NAME(name),@function; \
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.align ALIGNARG(4); \
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C_LABEL(name) \
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cfi_startproc; \
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CALL_MCOUNT
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#undef END
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#define END(name) \
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cfi_endproc; \
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ASM_SIZE_DIRECTIVE(name)
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#define ENTRY_CHK(name) ENTRY (name)
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#define END_CHK(name) END (name)
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/* If compiled for profiling, call `mcount' at the start of each function. */
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#ifdef PROF
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/* The mcount code relies on a normal frame pointer being on the stack
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to locate our caller, so push one just for its benefit. */
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#define CALL_MCOUNT \
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pushq %rbp; \
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cfi_adjust_cfa_offset(8); \
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movq %rsp, %rbp; \
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cfi_def_cfa_register(%rbp); \
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call JUMPTARGET(mcount); \
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popq %rbp; \
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cfi_def_cfa(rsp,8);
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#else
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#define CALL_MCOUNT /* Do nothing. */
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#endif
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/* Since C identifiers are not normally prefixed with an underscore
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on this system, the asm identifier `syscall_error' intrudes on the
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C name space. Make sure we use an innocuous name. */
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#define syscall_error __syscall_error
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#define mcount _mcount
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#define PSEUDO(name, syscall_name, args) \
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lose: \
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jmp JUMPTARGET(syscall_error) \
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.globl syscall_error; \
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ENTRY (name) \
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DO_CALL (syscall_name, args); \
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jb lose
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#undef PSEUDO_END
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#define PSEUDO_END(name) \
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END (name)
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#undef JUMPTARGET
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#ifdef PIC
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# ifdef BIND_NOW
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# define JUMPTARGET(name) *name##@GOTPCREL(%rip)
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# else
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# define JUMPTARGET(name) name##@PLT
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# endif
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#else
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# define JUMPTARGET(name) name
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#endif
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/* Local label name for asm code. */
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#ifndef L
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/* ELF-like local names start with `.L'. */
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# define L(name) .L##name
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#endif
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#define atom_text_section .section ".text.atom", "ax"
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/* Long and pointer size in bytes. */
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#define LP_SIZE 8
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/* Instruction to operate on long and pointer. */
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#define LP_OP(insn) insn##q
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/* Assembler address directive. */
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#define ASM_ADDR .quad
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/* Registers to hold long and pointer. */
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#define RAX_LP rax
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#define RBP_LP rbp
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#define RBX_LP rbx
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#define RCX_LP rcx
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#define RDI_LP rdi
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#define RDX_LP rdx
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#define RSI_LP rsi
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#define RSP_LP rsp
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#define R8_LP r8
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#define R9_LP r9
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#define R10_LP r10
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#define R11_LP r11
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#define R12_LP r12
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#define R13_LP r13
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#define R14_LP r14
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#define R15_LP r15
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#else /* __ASSEMBLER__ */
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/* Long and pointer size in bytes. */
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#define LP_SIZE "8"
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/* Instruction to operate on long and pointer. */
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#define LP_OP(insn) #insn "q"
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/* Assembler address directive. */
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#define ASM_ADDR ".quad"
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/* Registers to hold long and pointer. */
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#define RAX_LP "rax"
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#define RBP_LP "rbp"
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#define RBX_LP "rbx"
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#define RCX_LP "rcx"
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#define RDI_LP "rdi"
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#define RDX_LP "rdx"
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#define RSI_LP "rsi"
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#define RSP_LP "rsp"
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#define R8_LP "r8"
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#define R9_LP "r9"
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#define R10_LP "r10"
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#define R11_LP "r11"
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#define R12_LP "r12"
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#define R13_LP "r13"
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#define R14_LP "r14"
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#define R15_LP "r15"
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#endif /* __ASSEMBLER__ */
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#endif /* _X86_64_SYSDEP_H */
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