Hi

The AArch64 linker option to turn on BTI (--force-bti) warns in case 
there are input objects which have a missing GNU NOTE section for BTI. 
This patch is trying to improve the warnings that come out.

In order to do so, I propose adding a new argument to 
elf_merge_gnu_properties and the backend function merge_gnu_properties. 
This new argument makes sure that we now pass both the objects along 
with the properties to which they belong to. The x86 backend function 
has also been updated to match this
change.

Builds and regression tested on aarch64-none-linux-gnu and 
x86_64-pc-linux-gnu.

Is this ok for trunk?

Sudi

*** bfd/ChangeLog ***

2019-xx-xx  Sudakshina Das  <sudi.das@arm.com>

	* elf-bfd.h (struct elf_backend_data): Add argument to
	merge_gnu_properties.
	* elf-properties.c (elf_merge_gnu_properties): Add argument to
	itself and while calling bed->merge_gnu_properties.
	(elf_merge_gnu_property_list): Update the calls for
	elf_merge_gnu_properties.
	* elfnn-aarch64.c (elfNN_aarch64_merge_gnu_properties): Update handling
	of --force-bti warning and add argument.
	* elfxx-aarch64.c (_bfd_aarch64_elf_link_setup_gnu_properties): Add
	warning.
	* elfxx-x86.c (_bfd_x86_elf_merge_gnu_properties): Add argument.
	* elfxx-x86.h (_bfd_x86_elf_merge_gnu_properties): Likewise in
	declaration.

*** ld/ChangeLog ***

2019-xx-xx  Sudakshina Das  <sudi.das@arm.com>

	* testsuite/ld-aarch64/aarch64-elf.exp: Add new test.
	* testsuite/ld-aarch64/bti-plt-1.s: Add .ifdef for PAC note section.
	* testsuite/ld-aarch64/bti-plt-6.d: Update warning.
	* testsuite/ld-aarch64/bti-plt-7.d: Likewise.
	* testsuite/ld-aarch64/bti-warn.d: New test.