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Re: Question on generating object files with/without -fpic
On Mon, Jan 18, 2010 at 3:41 PM, Richard Guenther
<richard.guenther@gmail.com> wrote:
> On Mon, Jan 18, 2010 at 3:33 PM, chandra reddy <creddym@gmail.com> wrote:
>> Hi Eljay,
>>
>> My requirement is not generate two executable outputs. I want do the
>> following under a new command line option to gcc (new option is needed
>> because it is unusual producing two object files in single compilation)
>>
>> I want to create libabc.a and libabc.so in the following way:
>>
>> $gcc <cflags> -c <new_option>? -fpic a.c
>> $gcc <cflags> -c <new_option>? -fpic b.c
>> $gcc <cflags> -c <new_option>? -fpic c.c
>>
>> The output would be: a.o a.So b.o b.So c.o c.So
>> where a.o b.o c.o will be? generated with -fpic disabled
>> ????????? a.So b.So c.So will be generated with -fpic enabled
>> Now,
>>
>> I will create libabc.a and libabc.so like this.
>>
>> $ ar cq libabc a.o b.o c.o
>> $ld? -o libabc.so a.So b.So c.So
>>
>> I want this feature only to create object files not for executables. We have
>> to create thousands of static and dynamic libraries with and without -fpic
>> option.
>> It helps us if the above feature can be achieved in the gcc compiler.
>>
>> I can see that until reaching the function call "expand_gimple_basic_block"
>> in gcc compiler, the code flow is same with/without -fpic. After this
>> function call tree would differ.
>
> It already differs before (see targetm.binds_local).
Btw, if you just want to save compile time simply use the PIC
objects in the static archive.
Richard.