Re: about -fpic/-fPIC option for gcc

[Ian Lance Taylor <iant at google dot com>]

Lin George <george4academic@yahoo.com> writes:

> Do you mean -fpic and -fPIC will make GOT and PLT
> different? If yes, what are the differences?

I quote the documentation about -fPIC:

    If supported for the target machine, emit position-independent
    code, suitable for dynamic linking and avoiding any limit on the
    size of the global offset table.  This option makes a difference
    on the m68k, PowerPC and SPARC.

The difference is that with -fPIC there is no limit on the size of the
GOT.  The precise details depend on the platform.

Ian

> --- Ian Lance Taylor <iant@google.com> wrote:
> 
> > Lin George <george4academic@yahoo.com> writes:
> > 
> > > Could you provide a little more information
> > please? I
> > > mean what is the different things generated by
> > -fpic
> > > and -fPIC in a shared library?
> > 
> > To make the code position independent and to permit
> > the executable to
> > override symbols defined in the shared library, all
> > global variables
> > are accessed via a table of addresses (the Global
> > Offset Table, or
> > GOT) and all functions are called via a table of
> > branches (the
> > Procedure Linkage Table, or PLT).  The dynamic
> > linker initializes the
> > GOT and PLT at runtime.  The precise details depend
> > on the platform.
> > 
> > Ian
> > 
> 
> 
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