Ask for helping about LD linker
Dear,
Excuse me,I don't know how to remove unused functions and variable when
linking ELF.
please let me know ASAP.
eg.
int main()
{
int i;
i= 5;
return i;
}
char tmpBuffer[5];
char *getTmpBuff()
{
return tmpBuffer;
}
char *getTmpBuff1()
{
return tmpBuffer;
}
char *getTmpBuff2()
{
return tmpBuffer;
}
how to discard the functions(getTmpBuff,getTmpBuff1,getTmpBuff2) when linking.
Best regards.
2008-06-02
jian
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Re: Re: Ask for helping about LD linker
Dear Nick, I see, thank you so much. Best regards 2008-06-02 jian 发件人： Nick Clifton 发送时间： 2008-06-02 16:32:40 收件人： jian 抄送： bug-binutils 主题： Re: Ask for helping about LD linker Hi Jian, > But how to remove the unused functions in system library(maybe compile > the system library without --funciton-sections) when linking program. Short Answer: It cannot be done. Long Answer: If you are linking against a *shared* library then you will not be able to remove any functions in the shared library. (Nor would you want to - other programs may need those functions). If you are linking against a *static* system library (which has not been compiled with --ffunction-sections), then unused functions should not normally be copied into the executable. The exception is when an unused function is in the same object file inside the library as a used function (or used global symbol). Ie the linker only discards code at the object file level. If some part of an object file inside a static library is needed by the executable then the entire contents of that object file will be copies into the executable. Cheers Nick ___ bug-binutils mailing list bug-binutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-binutils
Re: Re: Ask for helping about LD linker
Dear Nick, Thanks for your advice,It works well according to your advice. But how to remove the unused functions in system library(maybe compile the system library without --funciton-sections) when linking program. Best regards. 2008-06-02 jian 发件人： Nick Clifton 发送时间： 2008-06-02 15:08:08 收件人： jian 抄送： bug-binutils 主题： Re: Ask for helping about LD linker Hi Jian, > Excuse me,I don't know how to remove unused functions and variable when > linking ELF. Compile your program with --function-sections. Link your program with -Wl,--gc-sections. Note: This feature is not implemented for all targets. If it does not work for you then it may be that the target you are working with is one of the unsupported targets. Cheers Nick ___ bug-binutils mailing list bug-binutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-binutils
