Home Original page

[PATCH 2/2] xcoff: implement linker relaxation

CHIGOT, CLEMENT clement.chigot@atos.net
Thu Mar 17 15:01:37 GMT 2022 
This patch enables a first part of the linker relaxation in
order to fix unreachable branches in large binaries.
It has been tested by compiling gcc. However, the exact
maximum branch offset (1<<25) could not be tested as other
problems are appearing. However, the generation of stubs
when considering that the maximum offset is (1<<24) is
working fine and able to fully compile gcc. This is simply
generating more stubs than actually needed.

Note that as I'll stop working for AIX at this end of this
month. Thus, I hope we'll have the time to merge it before.
Moreover, Kavana and Ayappan will retrieve my work and 
knowledge on Binutils for AIX. Thus, they will be able to submit
patches if anything goes wrong after the merge. I'm also adding
my personal mail in order to answer questions but I won't have
access to AIX anymore. 


bfd/ChangeLog:

	* coff-rs6000.c (xcoff_reloc_type_noop): Add info argument.
	(xcoff_reloc_type_fail): Likewise.
	(xcoff_reloc_type_pos): Likewise.
	(xcoff_reloc_type_neg): Likewise.
	(xcoff_reloc_type_rel): Likewise.
	(xcoff_reloc_type_toc): Likewise.
	(xcoff_reloc_type_ba): Likewise.
	(xcoff_reloc_type_crel): Likewise.
	(xcoff_reloc_type_tls): Likewise.
	(xcoff_reloc_type_br): Add stub handler.
	(xcoff_ppc_relocate_section): Add info to
	xcoff_calculate_relocation.
	(xcoff_stub_indirect_call_code): New constant.
	(xcoff_stub_shared_call_code): Likewise.
	(bfd_xcoff_backend_data): Add stub code fields.
	(bfd_pmac_xcoff_backend_data): Likewise.
	* coff64-rs6000.c (xcoff64_reloc_type_br): Add stub handler.
	(xcoff64_ppc_relocate_section): Add info to
	xcoff64_calculate_relocation.
	(xcoff64_stub_indirect_call_code): New constant.
	(xcoff64_stub_shared_call_code): Likewise.
	(bfd_xcoff_backend_data): Add stub code fields.
	(bfd_xcoff_aix5_backend_data): Likewise.
	* libxcoff.h (struct xcoff_backend_data_rec): Add stub fields.
	(bfd_xcoff_stub_indirect_call_code): New define.
	(bfd_xcoff_stub_indirect_call_size): New define.
	(bfd_xcoff_stub_shared_call_code): New define.
	(bfd_xcoff_stub_shared_call_size): New define.
	(xcoff_reloc_function): Add info argument.
	(enum xcoff_stub_type): New enum.
	(struct xcoff_stub_hash_entry): New structure.
	* xcofflink.c (struct xcoff_link_hash_table): Add stub hash
	table and params fields.
	(xcoff_stub_hash_entry): New define.
	(xcoff_stub_hash_lookup): New define.
	(stub_hash_newfunc): New function.
	(_bfd_xcoff_bfd_link_hash_table_free): Free the new stub hash
	table.
	(_bfd_xcoff_bfd_link_hash_table_create): Create the new stub
	hash table.
	(xcoff_link_add_symbols): Save rawsize for XTY_SD.
	(bfd_xcoff_link_init): New function.
	(xcoff_stub_csect_name): New function.
	(xcoff_stub_get_csect_in_range): New function.
	(xcoff_stub_name): New function.
	(bfd_xcoff_get_stub_entry): New function.
	(bfd_xcoff_type_of_stub): New function.
	(xcoff_add_stub): New function.
	(xcoff_build_one_stub): New function.
	(bfd_xcoff_size_stubs): New function.
	(bfd_xcoff_build_stubs): New function.
	(xcoff_stub_create_relocations): New function.
	(xcoff_link_input_bfd): Adapt relocations to stub.
	(xcoff_write_global_symbol): Adapt to new TOC entries generated
	for stubs.
	(_bfd_xcoff_bfd_final_link): Handle stub file.
	* xcofflink.h (struct bfd_xcoff_link_params): New structure.

ld/ChangeLog:

	* emultempl/aix.em (params): New variable.
	(stub_file): New variable.
	(xcoff_add_stub_section): New function.
	(xcoff_layout_sections_again): New function
	(hook_in_stub): New function.
	(_after_allocation): Add stub creation.
	(_create_output_section_statements): Allocate stub file and
	pass params to backend.



-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0002-xcoff-implement-linker-relaxation.patch
Type: application/octet-stream
Size: 56995 bytes
Desc: 0002-xcoff-implement-linker-relaxation.patch
URL: <https://sourceware.org/pipermail/binutils/attachments/20220317/3b06f0a0/attachment-0001.obj>
More information about the Binutils mailing list