From 845b51d665a3e63aa3a830d1cda6c4803fd35484 Mon Sep 17 00:00:00 2001 From: Paul Brook Date: Wed, 20 Feb 2008 15:17:56 +0000 Subject: 2008-02-20 Paul Brook ld/ * emultempl/armelf.em (OPTION_FIX_V4BX_INTERWORKING): Define. (PARSE_AND_LIST_LONGOPTS): Add fix-v4bx-interworking. (PARSE_AND_LIST_OPTIONS): Ditto. (PARSE_AND_LIST_ARGS_CASES): Handle OPTION_FIX_V4BX_INTERWORKING. * emulparams/armelf.sh (OTHER_TEXT_SECTIONS): Add .v4_bx. * emulparams/armelf_linux.sh (OTHER_TEXT_SECTIONS): Ditto. * emulparams/armnto.sh (OTHER_TEXT_SECTIONS): Ditto. * ld.texinfo: Document --fix-v4bx-interworking. ld/testsuite/ * ld-arm/armv4-bx.d: New test. * ld-arm/armv4-bx.s: New test. * ld-arm/arm.ld: Add .v4bx. * ld-arm/arm-elf.exp: Add armv4-bx. gas/testsuite/ * gas/arm/thumb.d: Exclude EABI targets. * gas/arm/arch4t.d: Exclude EABI targts. * gas/arm/v4bx.d: New test. * gas/arm/v4bx.s: New test. * gas/arm/thumb-eabi.d: New test. * gas/arm/arch4t-eabi.d: New test. gas/ * config/tc-arm.c (fix_v4bx): New variable. (do_bx): Generate V4BX relocations. (md_assemble): Allow bx on v4 codes when fix_v4bx. (md_apply_fix): Handle BFD_RELOC_ARM_V4BX. (tc_gen_reloc): Ditto. (OPTION_FIX_V4BX): Define. (md_longopts): Add fix-v4bx. (md_parse_option): Handle OPTION_FIX_V4BX. (md_show_usage): Document --fix-v4bx. * doc/c-arm.texi: Document --fix-v4bx. bfd/ * reloc.c: Add BFD_RELOC_ARM_V4BX. * elf32-arm.c (elf32_arm_reloc_map): Add BFD_RELOC_ARM_V4BX. (ARM_BX_GLUE_SECTION_NAME, ARM_BX_GLUE_SECTION_NAME): Define. (elf32_arm_link_hash_table): Add bx_glue_size and bx_glue_offset. Update comment for fix_v4bx. (elf32_arm_link_hash_table_create): Zero bx_glue_size and bx_glue_offset. (ARM_BX_VENEER_SIZE, armbx1_tst_insn, armbx2_moveq_insn, armbx3_bx_insn): New. (bfd_elf32_arm_allocate_interworking_sections): Allocate BX veneer section. (bfd_elf32_arm_add_glue_sections_to_bfd): Ditto. (bfd_elf32_arm_process_before_allocation): Record BX veneers. (record_arm_bx_glue, elf32_arm_bx_glue): New functions. (elf32_arm_final_link_relocate): Handle BX veneers. (elf32_arm_output_arch_local_syms): Output mapping symbol for .v4_bx. * bfd-in2.h: Regenerate. * libbfd.h: Regenerate. --- ld/ld.texinfo | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'ld/ld.texinfo') diff --git a/ld/ld.texinfo b/ld/ld.texinfo index 00081da..cda834a 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -5584,6 +5584,21 @@ linker, which causes v4t @code{BX rM} instructions to be rewritten as In the former case, the switch should not be used, and @samp{R_ARM_V4BX} relocations are ignored. +@cindex FIX_V4BX_INTERWORKING +@kindex --fix-v4bx-interworking +Replace @code{BX rM} instructions identified by @samp{R_ARM_V4BX} +relocations with a branch to the following veneer: + +@smallexample +TST rM, #1 +MOVEQ PC, rM +BX Rn +@end smallexample + +This allows generation of libraries/applications that work on ARMv4 cores +and are still interworking safe. Note that the above veneer clobbers the +condition flags, so may cause incorrect progrm behavior in rare cases. + @cindex USE_BLX @kindex --use-blx The @samp{--use-blx} switch enables the linker to use ARM/Thumb -- cgit v1.1