From bd97cb95f84989bc1e3e771718098411c34338e2 Mon Sep 17 00:00:00 2001 From: Daniel Jacobowitz Date: Mon, 6 Aug 2007 18:47:21 +0000 Subject: [PATCH] 2007-08-06 Paul Brook * elf32-arm.c (elf32_arm_link_hash_entry): Add plt_maybe_thumb_refcount. (elf32_arm_link_hash_newfunc): Set plt_maybe_thumb_refcount. (elf32_arm_copy_indirect_symbol): Ditto. (elf32_arm_adjust_dynamic_symbol): Ditto. (bfd_elf32_arm_process_before_allocation): Handle R_ARM_THM_JUMP24. (arm_add_to_rel): Ditto. (elf32_arm_final_link_relocate): Merge R_ARM_THM_JUMP24 with R_ARM_THM_CALL. Handle R_ARM_THM_JUMP19 against a PLT stub. (elf32_arm_gc_sweep_hook): Call check_use_blx. Update plt counts for R_ARM_THM_JUMP24 and R_ARM_THM_JUMP19. (elf32_arm_check_relocs): Update plt counts for R_ARM_THM_JUMP24 and R_ARM_THM_JUMP19. (allocate_dynrelocs): Use plt_maybe_thumb_refcount. (elf32_arm_finish_dynamic_symbol): Ditto. (elf32_arm_output_plt_map): Ditto. --- bfd/ChangeLog | 19 ++++++ bfd/elf32-arm.c | 158 ++++++++++++++++++++++-------------------------- 2 files changed, 90 insertions(+), 87 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 50ce8c0aff7..a410c9eaa65 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,22 @@ +2007-08-06 Paul Brook + + * elf32-arm.c (elf32_arm_link_hash_entry): Add + plt_maybe_thumb_refcount. + (elf32_arm_link_hash_newfunc): Set plt_maybe_thumb_refcount. + (elf32_arm_copy_indirect_symbol): Ditto. + (elf32_arm_adjust_dynamic_symbol): Ditto. + (bfd_elf32_arm_process_before_allocation): Handle R_ARM_THM_JUMP24. + (arm_add_to_rel): Ditto. + (elf32_arm_final_link_relocate): Merge R_ARM_THM_JUMP24 with + R_ARM_THM_CALL. Handle R_ARM_THM_JUMP19 against a PLT stub. + (elf32_arm_gc_sweep_hook): Call check_use_blx. Update plt counts + for R_ARM_THM_JUMP24 and R_ARM_THM_JUMP19. + (elf32_arm_check_relocs): Update plt counts for R_ARM_THM_JUMP24 + and R_ARM_THM_JUMP19. + (allocate_dynrelocs): Use plt_maybe_thumb_refcount. + (elf32_arm_finish_dynamic_symbol): Ditto. + (elf32_arm_output_plt_map): Ditto. + 2007-08-06 Daniel Jacobowitz * elf.c (rewrite_elf_program_header): Handle sections not sorted diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c index ed877f7ce3f..ef066d3a79e 100644 --- a/bfd/elf32-arm.c +++ b/bfd/elf32-arm.c @@ -2129,6 +2129,10 @@ struct elf32_arm_link_hash_entry so that we can emit the Thumb trampoline only if needed. */ bfd_signed_vma plt_thumb_refcount; + /* Some references from Thumb code may be eliminated by BL->BLX + conversion, so record them separately. */ + bfd_signed_vma plt_maybe_thumb_refcount; + /* Since PLT entries have variable size if the Thumb prologue is used, we need to record the index into .got.plt instead of recomputing it from the PLT offset. */ @@ -2267,6 +2271,7 @@ elf32_arm_link_hash_newfunc (struct bfd_hash_entry * entry, ret->relocs_copied = NULL; ret->tls_type = GOT_UNKNOWN; ret->plt_thumb_refcount = 0; + ret->plt_maybe_thumb_refcount = 0; ret->plt_got_offset = -1; ret->export_glue = NULL; } @@ -2422,6 +2427,8 @@ elf32_arm_copy_indirect_symbol (struct bfd_link_info *info, /* Copy over PLT info. */ edir->plt_thumb_refcount += eind->plt_thumb_refcount; eind->plt_thumb_refcount = 0; + edir->plt_maybe_thumb_refcount += eind->plt_maybe_thumb_refcount; + eind->plt_maybe_thumb_refcount = 0; if (dir->got.refcount <= 0) { @@ -3162,7 +3169,8 @@ bfd_elf32_arm_process_before_allocation (bfd *abfd, && r_type != R_ARM_PLT32 && r_type != R_ARM_CALL && r_type != R_ARM_JUMP24 - && r_type != R_ARM_THM_CALL) + && r_type != R_ARM_THM_CALL + && r_type != R_ARM_THM_JUMP24) continue; /* Get the section contents if we haven't done so already. */ @@ -3216,10 +3224,12 @@ bfd_elf32_arm_process_before_allocation (bfd *abfd, break; case R_ARM_THM_CALL: + case R_ARM_THM_JUMP24: /* This one is a call from thumb code. We look up the target of the call. If it is not a thumb target, we insert glue. */ - if (ELF_ST_TYPE (h->type) != STT_ARM_TFUNC && !globals->use_blx + if (ELF_ST_TYPE (h->type) != STT_ARM_TFUNC + && !(globals->use_blx && r_type == R_ARM_THM_CALL) && h->root.type != bfd_link_hash_undefweak) record_thumb_to_arm_glue (link_info, h); break; @@ -4996,6 +5006,7 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, case R_ARM_THM_XPC22: case R_ARM_THM_CALL: + case R_ARM_THM_JUMP24: /* Thumb BL (branch long instruction). */ { bfd_vma relocation; @@ -5059,7 +5070,7 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, && (h == NULL || splt == NULL || h->plt.offset == (bfd_vma) -1)) { - if (globals->use_blx) + if (globals->use_blx && r_type == R_ARM_THM_CALL) { /* Convert BL to BLX. */ lower_insn = (lower_insn & ~0x1000) | 0x0800; @@ -5072,7 +5083,8 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, else return bfd_reloc_dangerous; } - else if (sym_flags == STT_ARM_TFUNC && globals->use_blx) + else if (sym_flags == STT_ARM_TFUNC && globals->use_blx + && r_type == R_ARM_THM_CALL) { /* Make sure this is a BL. */ lower_insn |= 0x1800; @@ -5085,7 +5097,7 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, value = (splt->output_section->vma + splt->output_offset + h->plt.offset); - if (globals->use_blx) + if (globals->use_blx && r_type == R_ARM_THM_CALL) { /* If the Thumb BLX instruction is available, convert the BL to a BLX instruction to call the ARM-mode PLT entry. */ @@ -5125,7 +5137,7 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, if (signed_check > reloc_signed_max || signed_check < reloc_signed_min) overflow = TRUE; - if ((lower_insn & 0x1800) == 0x0800) + if ((lower_insn & 0x5000) == 0x4000) /* For a BLX instruction, make sure that the relocation is rounded up to a word boundary. This follows the semantics of the instruction which specifies that bit 1 of the target address will come from bit @@ -5152,79 +5164,6 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, } break; - case R_ARM_THM_JUMP24: - /* Thumb32 unconditional branch instruction. */ - { - bfd_vma relocation; - bfd_boolean overflow = FALSE; - bfd_vma upper_insn = bfd_get_16 (input_bfd, hit_data); - bfd_vma lower_insn = bfd_get_16 (input_bfd, hit_data + 2); - bfd_signed_vma reloc_signed_max = ((1 << (howto->bitsize - 1)) - 1) >> howto->rightshift; - bfd_signed_vma reloc_signed_min = ~ reloc_signed_max; - bfd_vma check; - bfd_signed_vma signed_check; - - /* Need to refetch the addend, reconstruct the top three bits, and glue the - two pieces together. */ - if (globals->use_rel) - { - bfd_vma S = (upper_insn & 0x0400) >> 10; - bfd_vma hi = (upper_insn & 0x03ff); - bfd_vma I1 = (lower_insn & 0x2000) >> 13; - bfd_vma I2 = (lower_insn & 0x0800) >> 11; - bfd_vma lo = (lower_insn & 0x07ff); - - I1 = !(I1 ^ S); - I2 = !(I2 ^ S); - S = !S; - - signed_addend = (S << 24) | (I1 << 23) | (I2 << 22) | (hi << 12) | (lo << 1); - signed_addend -= (1 << 24); /* Sign extend. */ - } - - /* ??? Should handle interworking? GCC might someday try to - use this for tail calls. */ - - relocation = value + signed_addend; - relocation -= (input_section->output_section->vma - + input_section->output_offset - + rel->r_offset); - - check = relocation >> howto->rightshift; - - /* If this is a signed value, the rightshift just dropped - leading 1 bits (assuming twos complement). */ - if ((bfd_signed_vma) relocation >= 0) - signed_check = check; - else - signed_check = check | ~((bfd_vma) -1 >> howto->rightshift); - - /* Assumes two's complement. */ - if (signed_check > reloc_signed_max || signed_check < reloc_signed_min) - overflow = TRUE; - - /* Put RELOCATION back into the insn. */ - { - bfd_vma S = (relocation & 0x01000000) >> 24; - bfd_vma I1 = (relocation & 0x00800000) >> 23; - bfd_vma I2 = (relocation & 0x00400000) >> 22; - bfd_vma hi = (relocation & 0x003ff000) >> 12; - bfd_vma lo = (relocation & 0x00000ffe) >> 1; - - I1 = !(I1 ^ S); - I2 = !(I2 ^ S); - - upper_insn = (upper_insn & (bfd_vma) 0xf800) | (S << 10) | hi; - lower_insn = (lower_insn & (bfd_vma) 0xd000) | (I1 << 13) | (I2 << 11) | lo; - } - - /* Put the relocated value back in the object file: */ - bfd_put_16 (input_bfd, upper_insn, hit_data); - bfd_put_16 (input_bfd, lower_insn, hit_data + 2); - - return (overflow ? bfd_reloc_overflow : bfd_reloc_ok); - } - case R_ARM_THM_JUMP19: /* Thumb32 conditional branch instruction. */ { @@ -5255,6 +5194,17 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto, signed_addend = addend; } + /* Handle calls via the PLT. */ + if (h != NULL && splt != NULL && h->plt.offset != (bfd_vma) -1) + { + value = (splt->output_section->vma + + splt->output_offset + + h->plt.offset); + /* Target the Thumb stub before the ARM PLT entry. */ + value -= PLT_THUMB_STUB_SIZE; + *unresolved_reloc_p = FALSE; + } + /* ??? Should handle interworking? GCC might someday try to use this for tail calls. */ @@ -6266,7 +6216,8 @@ arm_add_to_rel (bfd * abfd, { bfd_signed_vma addend; - if (howto->type == R_ARM_THM_CALL) + if (howto->type == R_ARM_THM_CALL + || howto->type == R_ARM_THM_JUMP24) { int upper_insn, lower_insn; int upper, lower; @@ -7400,6 +7351,8 @@ elf32_arm_gc_sweep_hook (bfd * abfd, sym_hashes = elf_sym_hashes (abfd); local_got_refcounts = elf_local_got_refcounts (abfd); + check_use_blx(globals); + relend = relocs + sec->reloc_count; for (rel = relocs; rel < relend; rel++) { @@ -7450,6 +7403,8 @@ elf32_arm_gc_sweep_hook (bfd * abfd, case R_ARM_JUMP24: case R_ARM_PREL31: case R_ARM_THM_CALL: + case R_ARM_THM_JUMP24: + case R_ARM_THM_JUMP19: case R_ARM_MOVW_ABS_NC: case R_ARM_MOVT_ABS: case R_ARM_MOVW_PREL_NC: @@ -7471,7 +7426,11 @@ elf32_arm_gc_sweep_hook (bfd * abfd, if (h->plt.refcount > 0) { h->plt.refcount -= 1; - if (ELF32_R_TYPE (rel->r_info) == R_ARM_THM_CALL) + if (r_type == R_ARM_THM_CALL) + eh->plt_maybe_thumb_refcount--; + + if (r_type == R_ARM_THM_JUMP24 + || r_type == R_ARM_THM_JUMP19) eh->plt_thumb_refcount--; } @@ -7673,6 +7632,8 @@ elf32_arm_check_relocs (bfd *abfd, struct bfd_link_info *info, case R_ARM_JUMP24: case R_ARM_PREL31: case R_ARM_THM_CALL: + case R_ARM_THM_JUMP24: + case R_ARM_THM_JUMP19: case R_ARM_MOVW_ABS_NC: case R_ARM_MOVT_ABS: case R_ARM_MOVW_PREL_NC: @@ -7708,7 +7669,15 @@ elf32_arm_check_relocs (bfd *abfd, struct bfd_link_info *info, it, even if it's an ABS32 relocation. */ h->plt.refcount += 1; + /* It's too early to use htab->use_blx here, so we have to + record possible blx references separately from + relocs that definitely need a thumb stub. */ + if (r_type == R_ARM_THM_CALL) + eh->plt_maybe_thumb_refcount += 1; + + if (r_type == R_ARM_THM_JUMP24 + || r_type == R_ARM_THM_JUMP19) eh->plt_thumb_refcount += 1; } @@ -8059,6 +8028,7 @@ elf32_arm_adjust_dynamic_symbol (struct bfd_link_info * info, linkage table, and we can just do a PC24 reloc instead. */ h->plt.offset = (bfd_vma) -1; eh->plt_thumb_refcount = 0; + eh->plt_maybe_thumb_refcount = 0; h->needs_plt = 0; } @@ -8073,6 +8043,7 @@ elf32_arm_adjust_dynamic_symbol (struct bfd_link_info * info, the link may change h->type. So fix it now. */ h->plt.offset = (bfd_vma) -1; eh->plt_thumb_refcount = 0; + eh->plt_maybe_thumb_refcount = 0; } /* If this is a weak symbol, and there is a real definition, the @@ -8150,6 +8121,7 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf) struct elf32_arm_link_hash_table *htab; struct elf32_arm_link_hash_entry *eh; struct elf32_arm_relocs_copied *p; + bfd_signed_vma thumb_refs; eh = (struct elf32_arm_link_hash_entry *) h; @@ -8191,7 +8163,11 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf) /* If we will insert a Thumb trampoline before this PLT, leave room for it. */ - if (!htab->use_blx && eh->plt_thumb_refcount > 0) + thumb_refs = eh->plt_thumb_refcount; + if (!htab->use_blx) + thumb_refs += eh->plt_maybe_thumb_refcount; + + if (thumb_refs > 0) { h->plt.offset += PLT_THUMB_STUB_SIZE; s->size += PLT_THUMB_STUB_SIZE; @@ -8900,6 +8876,7 @@ elf32_arm_finish_dynamic_symbol (bfd * output_bfd, struct bfd_link_info * info, } else { + bfd_signed_vma thumb_refs; /* Calculate the displacement between the PLT slot and the entry in the GOT. The eight-byte offset accounts for the value produced by adding to pc in the first instruction @@ -8908,7 +8885,11 @@ elf32_arm_finish_dynamic_symbol (bfd * output_bfd, struct bfd_link_info * info, BFD_ASSERT ((got_displacement & 0xf0000000) == 0); - if (!htab->use_blx && eh->plt_thumb_refcount > 0) + thumb_refs = eh->plt_thumb_refcount; + if (!htab->use_blx) + thumb_refs += eh->plt_maybe_thumb_refcount; + + if (thumb_refs > 0) { put_thumb_insn (htab, output_bfd, elf32_arm_plt_thumb_stub[0], ptr - 4); @@ -9638,10 +9619,13 @@ elf32_arm_output_plt_map (struct elf_link_hash_entry *h, void *inf) } else { - bfd_boolean thumb_stub; + bfd_signed_vma thumb_refs; + + thumb_refs = eh->plt_thumb_refcount; + if (!htab->use_blx) + thumb_refs += eh->plt_maybe_thumb_refcount; - thumb_stub = eh->plt_thumb_refcount > 0 && !htab->use_blx; - if (thumb_stub) + if (thumb_refs > 0) { if (!elf32_arm_ouput_plt_map_sym (osi, ARM_MAP_THUMB, addr - 4)) return FALSE; @@ -9655,7 +9639,7 @@ elf32_arm_output_plt_map (struct elf_link_hash_entry *h, void *inf) /* A three-word PLT with no Thumb thunk contains only Arm code, so only need to output a mapping symbol for the first PLT entry and entries with thumb thunks. */ - if (thumb_stub || addr == 20) + if (thumb_refs > 0 || addr == 20) { if (!elf32_arm_ouput_plt_map_sym (osi, ARM_MAP_ARM, addr)) return FALSE; -- 2.30.2