Re: [PATCH] gold: add dynamic symbol support for ARM target.

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

"Doug Kwan (éæå)" <dougkwan@google.com> writes:

> 2009-05-28  Doug Kwan  <dougkwan@google.com>
>
> 	* gold/arm.cc (Output_data_plt_arm): Forward declaration for new
> 	template class.
> 	(class Target_arm): Update comments.
> 	(Target_arm::Target_arm): Initialize new data members GOT_,
> 	PLT_, GOT_PLT_, REL_DYN_, COPY_RELOCS_ and DYNBSS_.
> 	Declare new methods Target_arm::got_section, Target_arm::make_plt_entry
> 	and Target_arm::rel_dyn_section.
> 	Declare new_enum Target_arm::Got_type.
> 	Declare new data members GOT_, PLT_, GOT_PLT_, REL_DYN_, COPY_RELOCS_
> 	and DYNBSS_.
> 	(Target_arm::got_size, Target_arm::plt_section,
> 	Target_arm::may_need_copy_reloc and Target_arm::copy_reloc): Define
> 	new methods inside class defintion.
> 	(Target_arm::got_section): Define new method.
> 	(Target_arm::rel_dyn_section): Same.
> 	(Output_data_plt_arm): New template class.
> 	(Output_data_plt_arm::Output_data_plt_arm): Define constructor.
> 	(Output_data_plt_arm:do_adjust_output_section): Define new method.
> 	(Output_data_plt_arm::add_entry): Same.
> 	(Output_data_plt_arm::first_plt_entry): Define new
> 	static data member for PLT instruction template.
> 	(Output_data_plt_arm::plt_entry): Same.
> 	(Output_data_plt_arm::do_write): Define new method.
> 	(Target_arm::make_plt_entry): Same.
> 	(Target_arm::do_finalize_sections): Same.
> 	(Target_arm::do_dynsym_value): Same.


> +// The first entry in the PLT.
> +template<bool big_endian>
> +const uint32_t Output_data_plt_arm<big_endian>::first_plt_entry[5] =
> +{
> +  0xe52de004,	// str   lr, [sp, #-4]!
> +  0xe59fe004,   // ldr   lr, [pc, #4]
> +  0xe08fe00e,	// add   lr, pc, lr 
> +  0xe5bef008,	// ldr   pc, [lr, #8]!
> +  0x00000000,	// &GOT[0] - .
> +};
> +
> +// Subsequent entries in the PLT.
> +
> +template<bool big_endian>
> +const uint32_t Output_data_plt_arm<big_endian>::plt_entry[3] =
> +{
> +  0xe28fc600,	// add   ip, pc, #0xNN00000
> +  0xe28cca00,	// add   ip, ip, #0xNN000
> +  0xe5bcf000,	// ldr   pc, [ip, #0xNNN]!
> +};

As Richard said, this needs to be more flexible, but you can do that
later if you like.  At least add some FIXME comments for now.


> +// Return the value to use for a dynamic which requires special
> +// treatment.  This is how we support equality comparisons of function
> +// pointers across shared library boundaries, as described in the
> +// processor specific ABI supplement.

s/for a dynamic/for a dynamic symbol/


OK with those changes.

Thanks.

Ian