如何确定gcc默认将哪些命令行选项传递给ld? [英] How to determine which command line options gcc passes to ld by default?
问题描述
考虑hello world C程序:
hello.c :
#includestdio.h
int main()
{
printf(Hello,World!\\\
) ;
}
如果我打电话:
$ gcc -c hello.c -o hello.o
它会产生一个ELF可重定位文件 hello.o
如果我然后打电话: $ gcc hello.o -o hello [1]
它会将hello.o与ld关联起来,并生成一个ELF可执行文件 hello 然而如果我直接调用ld <$ c
$ b $ $ $ $ $ $ ld hello.o -o hello [2]
我收到这些错误:
/usr/bin/ld.bfd.real:warning:找不到条目符号_start
test.c :(。text + 0xa):对`puts'的未定义引用
gcc必须将其他选项传递给ld(例如链接C库)。
有没有办法确定命令行gcc正在传递给ld in command [1]
?
是的,您可以使用 gcc -v hello.o -o hello
获取链接。对于你的例子,在我的ubuntu机器上,我得到这个链接(为了可读性编辑为多行):
$ b
/ usr / lib /gcc/x86_64-linux-gnu/4.4.5/collect2
--build-id
--eh-frame-hdr
-m elf_x86_64
--hash-style = gnu
-dynamic-linker
/lib64/ld-linux-x86-64.so.2
-o hello
-z relro
/ usr / lib /gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.5 /../../../../lib/crti.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/crtbegin.o
-L / usr /lib/gcc/x86_64-linux-gnu/4.4.5
-L / usr / lib / gcc / x86_64-linux-gnu / 4.4.5
-L / usr / lib / gcc / x86_64 -linux-gnu / 4.4.5 /../../../../ lib
-L / lib /../ lib
-L / usr / lib /../ lib
-L / usr / lib / gcc / x86_64-linux-gnu / 4.4.5 /../../ -L / usr / lib / x86_64-linux-gnu
hello.o
-lgcc
- 需要的-lgcc_s - 不需要的
-lc
-lgcc
- 需要的-lgcc_s - 无-as-needed
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/crtend.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/。 ./。 ./../../lib/crtn.o
请注意 collect2
只是 ld
的别名。
Consider the hello world C program:
hello.c:
#include "stdio.h"
int main()
{
printf("Hello, World!\n");
}
If I call:
$ gcc -c hello.c -o hello.o
It will produce an ELF Relocatable File hello.o
If I then call:
$ gcc hello.o -o hello [1]
It will link hello.o with ld and produce an ELF Executable File hello
However if I call ld directly [2]
instead of [1]
:
$ ld hello.o -o hello [2]
I get these errors:
/usr/bin/ld.bfd.real: warning: cannot find entry symbol _start
test.c:(.text+0xa): undefined reference to `puts'
gcc must be passing other options to ld (to link the C library for example).
Is there anyway to determine exactly what the command-line gcc is passing through to ld in command [1]
?
Yes, you can use gcc -v hello.o -o hello
to get the link line. For your example on my ubuntu machine, I get this link line (edited to be multiline for readability):
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/collect2
--build-id
--eh-frame-hdr
-m elf_x86_64
--hash-style=gnu
-dynamic-linker
/lib64/ld-linux-x86-64.so.2
-o hello
-z relro
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crti.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/crtbegin.o
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.5
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.5
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib
-L/lib/../lib
-L/usr/lib/../lib
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../.. -L/usr/lib/x86_64-linux-gnu
hello.o
-lgcc
--as-needed -lgcc_s --no-as-needed
-lc
-lgcc
--as-needed -lgcc_s --no-as-needed
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/crtend.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crtn.o
Note that collect2
is just an alias for ld
.
这篇关于如何确定gcc默认将哪些命令行选项传递给ld?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!