Re: mips-vxworks support

[Thiemo Seufer <ths at networkno dot de>]

On Mon, Mar 13, 2006 at 09:17:04PM +0000, Richard Sandiford wrote:
> This patch adds MIPS VxWorks support.  VxWorks uses the same style
> of ABI for all architectures, which means that for MIPS, it's very
> different from SVR4-based ports.  The main differences are:
> 
>   - VxWorks uses a "normal" PLT (with JUMP_SLOT relocs, etc.).
>   - VxWorks uses copy relocs.
>   - Because of the above, executables do not use PIC, and do not use a GOT.
>   - R_MIPS_CALL16 relocations point to a .got.plt entry instead of a
>     normal .got entry.
>   - R_MIPS_GOT16 relocations evaluate to "G" for all symbols, not just
>     global ones.
> 
> I've tried to make the comments as descriptive as possible.  Note that
> the second half of _bfd_mips_vxworks_adjust_dynamic_symbol (the bit
> after the "h->needs_plt" block) is boiler-plate.  There's similar
> code in many ports.
> 
> The different handling of R_MIPS_GOT16 means that we need to use
> different macro expansions for VxWorks.  The patch adds a VXWORKS_PIC
> enumeration for this.  Most of the code is similar to SVR4_PIC,
> and since that's the only other PIC model we support these days,
> it usually redundant to check the value of mips_pic when handling
> mips_pic != NO_PIC.  Most of the checks are left over from
> EMBEDDED_PIC days.
> 
> Tested on mips64-elf, mips64-linux-gnu, mips-elf, mipsisa32-elf,
> mipsisa64-elf, mips-linux-gnu and mips-vxworks.  OK to install?
> 
> Richard
> 
> 
> 2006-03-13 Richard Sandiford  <richard@codesourcery.com>
> 	   Daniel Jacobowitz  <dan@codesourcery.com>
> 	   Phil Edwards  <phil@codesourcery.com>
> 	   Zack Weinberg  <zack@codesourcery.com>
> 	   Mark Mitchell  <mark@codesourcery.com>
> 	   Nathan Sidwell  <nathan@codesourcery.com>
> 
> bfd/
> 	* bfd-in2.h: Regenerate.
> 	* config.bfd (mips*-*-vxworks*, mips*el-*-vxworks*): New stanzas.
> 	* configure.in (bfd_elf32_bigmips_vxworks_vec): New stanza.
> 	(bfd_elf32_littlemips_vxworks_vec): Likewise.
> 	(bfd_elf32_bigmips_vec): Add elf-vxworks.lo.
> 	(bfd_elf32_littlemips_vec): Likewise.
> 	(bfd_elf32_nbigmips_vec): Likewise.
> 	(bfd_elf32_nlittlemips_vec): Likewise.
> 	(bfd_elf32_ntradbigmips_vec): Likewise.
> 	(bfd_elf32_ntradlittlemips_vec): Likewise.
> 	(bfd_elf32_tradbigmips_vec): Likewise.
> 	(bfd_elf32_tradlittlemips_vec): Likewise.
> 	(bfd_elf64_bigmips_vec): Likewise.
> 	(bfd_elf64_littlemips_vec): Likewise.
> 	(bfd_elf64_tradbigmips_vec): Likewise.
> 	(bfd_elf64_tradlittlemips_vec): Likewise.
> 	* elf32-mips.c: Include elf-vxworks.h.
> 	(mips_info_to_howto_rel): Use elf_backend_mips_rtype_to_howto
> 	instead of calling mips_elf32_rtype_to_howto directly.
> 	(mips_vxworks_copy_howto_rela): New reloc howto.
> 	(mips_vxworks_jump_slot_howto_rela): Likewise.
> 	(mips_vxworks_bfd_reloc_type_lookup): New function.
> 	(mips_vxworks_rtype_to_howto): Likewise.
> 	(mips_vxworks_final_write_processing): Likewise.
> 	(TARGET_LITTLE_SYM, TARGET_LITTLE_NAME): Override for VxWorks.
> 	(TARGET_BIG_SYM, TARGET_BIG_NAME, elf_bed, ELF_MAXPAGESIZE): Likewise.
> 	(elf_backend_want_got_plt): Likewise.
> 	(elf_backend_want_plt_sym): Likewise.
> 	(elf_backend_got_symbol_offset): Likewise.
> 	(elf_backend_want_dynbss): Likewise.
> 	(elf_backend_may_use_rel_p): Likewise.
> 	(elf_backend_may_use_rela_p): Likewise.
> 	(elf_backend_default_use_rela_p): Likewise.
> 	(elf_backend_got_header_size: Likewise.
> 	(elf_backend_plt_readonly): Likewise.
> 	(bfd_elf32_bfd_reloc_type_lookup): Likewise.
> 	(elf_backend_mips_rtype_to_howto): Likewise.
> 	(elf_backend_adjust_dynamic_symbol): Likewise.
> 	(elf_backend_finish_dynamic_symbol): Likewise.
> 	(bfd_elf32_bfd_link_hash_table_create): Likewise.
> 	(elf_backend_add_symbol_hook): Likewise.
> 	(elf_backend_link_output_symbol_hook): Likewise.
> 	(elf_backend_emit_relocs): Likewise.
> 	(elf_backend_final_write_processing: Likewise.
> 	(elf_backend_additional_program_headers): Likewise.
> 	(elf_backend_modify_segment_map): Likewise.
> 	(elf_backend_symbol_processing): Likewise.
> 	* elfxx-mips.c: Include elf-vxworks.h.
> 	(mips_elf_link_hash_entry): Add is_relocation_target and
> 	is_branch_target fields.
> 	(mips_elf_link_hash_table): Add is_vxworks, srelbss, sdynbss, srelplt,
> 	srelplt2, sgotplt, splt, plt_header_size and plt_entry_size fields.
> 	(MIPS_ELF_RELA_SIZE, MIPS_ELF_REL_DYN_NAME): New macros.
> 	(MIPS_RESERVED_GOTNO): Take a mips_elf_link_hash_table argument.
> 	Return 3 for VxWorks.
> 	(ELF_MIPS_GP_OFFSET): Change the argument from a bfd to a
> 	mips_elf_link_hash_table.  Return 0 for VxWorks.
> 	(MIPS_ELF_GOT_MAX_SIZE): Change the argument from a bfd to a
> 	mips_elf_link_hash_table.  Update the call to ELF_MIPS_GP_OFFSET.
> 	(mips_vxworks_exec_plt0_entry): New variable.
> 	(mips_vxworks_exec_plt_entry): Likewise.
> 	(mips_vxworks_shared_plt0_entry): Likewise.
> 	(mips_vxworks_shared_plt_entry): Likewise.
> 	(mips_elf_link_hash_newfunc): Initialize the new hash_entry fields.
> 	(mips_elf_rel_dyn_section): Change the bfd argument to a
> 	mips_elf_link_hash_table.  Use MIPS_ELF_REL_DYN_NAME to get
> 	the name of the section.
> 	(mips_elf_initialize_tls_slots): Update the call to
> 	mips_elf_rel_dyn_section.
> 	(mips_elf_gotplt_index): New function.
> 	(mips_elf_local_got_index): Add an input_section argument.
> 	Update the call to mips_elf_create_local_got_entry.
> 	(mips_elf_got_page): Likewise.
> 	(mips_elf_got16_entry): Likewise.
> 	(mips_elf_create_local_got_entry): Add bfd_link_info and input_section
> 	arguments.  Create dynamic relocations for each entry on VxWorks.
> 	(mips_elf_merge_gots): Update the use of MIPS_ELF_GOT_MAX_SIZE.
> 	(mips_elf_multi_got): Update the uses of MIPS_ELF_GOT_MAX_SIZE
> 	and MIPS_RESERVED_GOTNO.
> 	(mips_elf_create_got_section): Update the uses of
> 	MIPS_ELF_GOT_MAX_SIZE.  Create .got.plt on VxWorks.
> 	(is_gott_symbol): New function.
> 	(mips_elf_calculate_relocation): Use a dynobj local variable.
> 	Update the calls to mips_elf_local_got_index, mips_elf_got16_entry and
> 	mips_elf_got_page_entry.  Set G to the .got.plt entry when calculating
> 	VxWorks R_MIPS_CALL* relocations.  Calculcate and use G for all GOT
> 	relocations on VxWorks.  Add dynamic relocations for references
> 	to the VxWorks __GOTT_BASE__ and __GOTT_INDEX__ symbols.  Don't
> 	create dynamic relocations for R_MIPS_32, R_MIPS_REL32 or R_MIPS_64
> 	in VxWorks executables.
> 	(mips_elf_allocate_dynamic_relocations): Add a bfd_link_info argument.
> 	Use MIPS_ELF_RELA_SIZE to calculate the size of a VxWorks entry.
> 	Don't allocate a null entry on VxWorks.
> 	(mips_elf_create_dynamic_relocation): Update the call to
> 	mips_elf_rel_dyn_section.  Use absolute rather than relative
> 	relocations for VxWorks, and make them RELA rather than REL.
> 	(_bfd_mips_elf_create_dynamic_sections): Don't make .dynamic
> 	read-only on VxWorks.  Update the call to mips_elf_rel_dyn_section.
> 	Create the .plt, .rela.plt, .dynbss and .rela.bss sections on
> 	VxWorks.  Likewise create the _PROCEDURE_LINKAGE_TABLE symbol.
> 	Call elf_vxworks_create_dynamic_sections for VxWorks and
> 	initialize the plt_header_size and plt_entry_size fields.
> 	(_bfd_mips_elf_check_relocs): Don't allow GOT relocations to be
> 	used in VxWorks executables.  Don't allocate dynamic relocations
> 	for R_MIPS_32, R_MIPS_REL32 or R_MIPS_64 in VxWorks executables.
> 	Set is_relocation_target for each symbol referenced by a relocation.
> 	Allocate .rela.dyn entries for relocations against the special
> 	VxWorks __GOTT_BASE__ and __GOTT_INDEX__ symbols.  Create GOT
> 	entries for all VxWorks R_MIPS_GOT16 relocations.  Don't allocate
> 	a global GOT entry for symbols mentioned in VxWorks R_MIPS_CALL*,
> 	R_MIPS_32, R_MIPS_REL32 or R_MIPS_64 relocations.  Update the calls
> 	to mips_elf_rel_dyn_section and mips_elf_allocate_dynamic_relocations.
> 	Set is_branch_target for symbols mentioned in R_MIPS_PC16 or R_MIPS_26
> 	relocations.  Don't set no_fn_stub on VxWorks.
> 	(_bfd_mips_elf_adjust_dynamic_symbol): Update the call to
> 	mips_elf_allocate_dynamic_relocations.
> 	(_bfd_mips_vxworks_adjust_dynamic_symbol): New function.
> 	(_bfd_mips_elf_always_size_sections): Do not allocate GOT page
> 	entries for VxWorks, and do not create multiple GOTs.
> 	(_bfd_mips_elf_size_dynamic_sections): Use MIPS_ELF_REL_DYN_NAME.
> 	Handle .got specially for VxWorks.  Update the uses of
> 	MIPS_RESERVED_GOTNO and mips_elf_allocate_dynamic_relocations.
> 	Check for sgotplt and splt.  Allocate the .rel(a).dyn contents last,
> 	once its final size is known.  Set DF_TEXTREL for VxWorks.  Add
> 	DT_RELA, DT_RELASZ, DT_RELAENT, DT_PLTREL, DT_PLTRELSZ and DT_JMPREL
> 	tags on VxWorks.  Do not add the MIPS-specific tags for VxWorks.
> 	(_bfd_mips_vxworks_finish_dynamic_symbol): New function.
> 	(mips_vxworks_finish_exec_plt): Likewise.
> 	(mips_vxworks_finish_shared_plt): Likewise.
> 	(_bfd_mips_elf_finish_dynamic_sections): Remove an unncessary call
> 	to mips_elf_rel_dyn_section.  Use a VxWorks-specific value of
> 	DT_PLTGOT.  Handle DT_RELA, DT_RELASZ, DT_RELAENT, DT_PLTREL,
> 	DT_PLTRELSZ and DT_JMPREL.  Update the uses of MIPS_RESERVED_GOTNO
> 	and mips_elf_rel_dyn_section.  Use a different GOT header for
> 	VxWorks.  Don't sort .rela.dyn on VxWorks.  Finish the PLT on VxWorks.
> 	(_bfd_mips_elf_link_hash_table_create): Initialize the new
> 	mips_elf_link_hash_table fields.
> 	(_bfd_mips_vxworks_link_hash_table_create): New function.
> 	(_bfd_mips_elf_final_link): Set the GP value to _GLOBAL_OFFSET_TABLE_
> 	on VxWorks.  Update the call to ELF_MIPS_GP_OFFSET.
> 	* elfxx-mips.h (_bfd_mips_vxworks_adjust_dynamic_symbol): Declare.
> 	(_bfd_mips_vxworks_finish_dynamic_symbol): Likewise.
> 	(_bfd_mips_vxworks_link_hash_table_create): Likewise.
> 	* libbfd.h: Regenerate.
> 	* Makefile.am (elfxx-mips.lo): Depend on elf-vxworks.h.
> 	(elf32-mips.lo): Likewise.
> 	* Makefile.in: Regenerate.
> 	* reloc.c (BFD_RELOC_MIPS_COPY, BFD_RELOC_MIPS_JUMP_SLOT): Declare.
> 	* targets.c (bfd_elf32_bigmips_vxworks_vec): Declare.
> 	(bfd_elf32_littlemips_vxworks_vec): Likewise.
> 	(_bfd_target_vector): Add entries for them.
> 
> gas/
> 	* config/tc-mips.c (mips_target_format): Handle vxworks targets.
> 	(md_begin): Complain about -G being used for PIC.  Don't change
> 	the text, data and bss alignments on VxWorks.
> 	(reloc_needs_lo_p): Don't return true for R_MIPS_GOT16 when
> 	generating VxWorks PIC.
> 	(load_address): Extend SVR4_PIC handling to VXWORKS_PIC.
> 	(macro): Likewise, but do not treat la $25 specially for
> 	VxWorks PIC, and do not handle jal.
> 	(OPTION_MVXWORKS_PIC): New macro.
> 	(md_longopts): Add -mvxworks-pic.
> 	(md_parse_option): Don't complain about using PIC and -G together here.
> 	Handle OPTION_MVXWORKS_PIC.
> 	(md_estimate_size_before_relax): Always use the first relaxation
> 	sequence on VxWorks.
> 	* config/tc-mips.h (VXWORKS_PIC): New.
> 
> gas/testsuite/
> 	* gas/mips/vxworks1.s, gas/mips/vxworks1.d,
> 	* gas/mips/vxworks1-xgot.d: New tests.
> 	* gas/mips/mips.exp: Run them.  Do not run other tests on VxWorks.
> 	
> include/elf/
> 	* mips.h (R_MIPS_COPY, R_MIPS_JUMP_SLOT): New relocs.
> 
> ld/
> 	* configure.tgt (mips*el-*-vxworks*, mips*-*-vxworks*): Use
> 	separate VxWorks emulations.
> 	* emulparams/elf32ebmipvxworks.sh: New file.
> 	* emulparams/elf32elmipvxworks.sh: New file.
> 	* Makefile.am (ALL_EMULATIONS): Add eelf32ebmipvxworks.o and
> 	eelf32elmipvxworks.o.
> 	(eelf32ebmipvxworks.c, eelf32elmipvxworks.c): New rules.
> 	* Makefile.in: Regenerate.
> 
> ld/testsuite/
> 	* ld-mips/vxworks1.dd, ld-mips/vxworks1.ld, ld-mips/vxworks1-lib.dd,
> 	* ld-mips/vxworks1-lib.nd, ld-mips/vxworks1-lib.rd,
> 	* ld-mips/vxworks1-lib.s, ld-mips/vxworks1.rd, ld-mips/vxworks1.s,
> 	* ld-mips/vxworks1-static.d, ld-mips/vxworks2.s, ld-mips/vxworks2.sd,
> 	* ld-mips/vxworks2-static.sd: New tests.
> 	* ld-mips/mips-elf.exp: Run them.

Ok.


Thiemo