查看方式
使用 gcc 命令可以查看其使用的默认脚本
gcc -Wl,-verbose
脚本内容
using internal linker script:
==================================================
/* Script for -z combreloc: combine and sort reloc sections */
/* Copyright (C) 2014-2015 Free Software Foundation, Inc.
Copying and distribution of this script, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved. */
OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64",
"elf64-x86-64")
OUTPUT_ARCH(i386:x86-64)
ENTRY(_start)
SEARCH_DIR("=/usr/local/lib/x86_64-linux-gnu"); SEARCH_DIR("=/lib/x86_64-linux-gnu"); SEARCH_DIR("=/usr/lib/x86_64-linux-gnu"); SEARCH_DIR("=/usr/local/lib64"); SEARCH_DIR("=/lib64"); SEARCH_DIR("=/usr/lib64"); SEARCH_DIR("=/usr/local/lib"); SEARCH_DIR("=/lib"); SEARCH_DIR("=/usr/lib"); SEARCH_DIR("=/usr/x86_64-linux-gnu/lib64"); SEARCH_DIR("=/usr/x86_64-linux-gnu/lib");
SECTIONS
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KEEP (*(.preinit_array))
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PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*)))
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PROVIDE_HIDDEN (__init_array_end = .);
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KEEP (*(.fini_array EXCLUDE_FILE (*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o ) .dtors))
PROVIDE_HIDDEN (__fini_array_end = .);
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the constructors, so we make sure it is
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linker won't look for a file to match a
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KEEP (*crtbegin.o(.ctors))
KEEP (*crtbegin?.o(.ctors))
/* We don't want to include the .ctor section from
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The .ctor section from the crtend file contains the
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KEEP (*(SORT(.ctors.*)))
KEEP (*(.ctors))
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KEEP (*crtbegin.o(.dtors))
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}
==================================================
可以看出代码段总是从 0x400000 开始。
对一个 c 文件 c.c
cat c.c
int main()
{}
可以查看代码段中 main 所在的地址就是 00000000004004d6 T main
nm c
0000000000601030 B __bss_start
0000000000601030 b completed.7594
0000000000601020 D __data_start
0000000000601020 W data_start
0000000000400410 t deregister_tm_clones
0000000000400490 t __do_global_dtors_aux
0000000000600e18 t __do_global_dtors_aux_fini_array_entry
0000000000601028 D __dso_handle
0000000000600e28 d _DYNAMIC
0000000000601030 D _edata
0000000000601038 B _end
0000000000400564 T _fini
00000000004004b0 t frame_dummy
0000000000600e10 t __frame_dummy_init_array_entry
0000000000400698 r __FRAME_END__
0000000000601000 d _GLOBAL_OFFSET_TABLE_
w __gmon_start__
0000000000400574 r __GNU_EH_FRAME_HDR
0000000000400390 T _init
0000000000600e18 t __init_array_end
0000000000600e10 t __init_array_start
0000000000400570 R _IO_stdin_used
w _ITM_deregisterTMCloneTable
w _ITM_registerTMCloneTable
0000000000600e20 d __JCR_END__
0000000000600e20 d __JCR_LIST__
w _Jv_RegisterClasses
0000000000400560 T __libc_csu_fini
00000000004004f0 T __libc_csu_init
U __libc_start_main@@GLIBC_2.2.5
00000000004004d6 T main
0000000000400450 t register_tm_clones
00000000004003e0 T _start
0000000000601030 D __TMC_END__
上篇大小端以及转换