diff options
| -rw-r--r-- | bfd/ChangeLog | 17 | ||||
| -rw-r--r-- | bfd/coff-mips.c | 253 |
2 files changed, 226 insertions, 44 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 085fc84..f6f6b26 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,20 @@ +Thu Apr 7 14:23:05 1994 Ian Lance Taylor (ian@tweedledumb.cygnus.com) + + * coff-mips.c (mips_howto_table): Add entry for MIPS_R_SWITCH. + (mips_ecoff_swap_reloc_in): For MIPS_R_SWTICH, copy r_symndx into + r_offset and set r_symndx to RELOC_SECTION_TEXT. + (mips_ecoff_swap_reloc_out): For MIPS_R_SWITCH, get the r_symndx + value from the r_offset field. + (mips_adjust_reloc_in): Maximum r_type value is now MIPS_R_SWITCH. + For MIPS_R_SWITCH, copy the r_offset field into the addend field. + (mips_adjust_reloc_out): For MIPS_R_SWITCH, copy the addend field + into the r_offset field. + (mips_switch_reloc): New function. + (mips_bfd_reloc_type_lookup): Translate BFD_RELOC_GPREL32 into + MIPS_R_SWITCH. + (mips_relocate_section): Handle MIPS_R_SWITCH. + (mips_relax_section): Adjust MIPS_R_SWITCH offset if necessary. + Thu Apr 7 11:10:51 1994 Jeffrey A. Law (law@snake.cs.utah.edu) * elfcode.h (elf_set_section_contents): Support calling the backend diff --git a/bfd/coff-mips.c b/bfd/coff-mips.c index b3c2b81..34822cf 100644 --- a/bfd/coff-mips.c +++ b/bfd/coff-mips.c @@ -72,6 +72,13 @@ static bfd_reloc_status_type mips_gprel_reloc PARAMS ((bfd *abfd, asection *section, bfd *output_bfd, char **error)); +static bfd_reloc_status_type mips_switch_reloc PARAMS ((bfd *abfd, + arelent *reloc, + asymbol *symbol, + PTR data, + asection *section, + bfd *output_bfd, + char **error)); static void mips_relocate_refhi PARAMS ((struct internal_reloc *refhi, struct internal_reloc *reflo, bfd *input_bfd, @@ -262,6 +269,26 @@ static reloc_howto_type mips_howto_table[] = true, /* partial_inplace */ 0xffff, /* src_mask */ 0xffff, /* dst_mask */ + true), /* pcrel_offset */ + + /* This reloc is a Cygnus extension used when generating position + independent code for embedded systems. It represents an entry in + a switch table, which is the difference between two symbols in + the .text section. The symndx is actually the offset from the + reloc address to the subtrahend. See include/coff/mips.h for + more details. */ + HOWTO (MIPS_R_SWITCH, /* type */ + 0, /* rightshift */ + 2, /* size (0 = byte, 1 = short, 2 = long) */ + 32, /* bitsize */ + true, /* pc_relative */ + 0, /* bitpos */ + complain_overflow_dont, /* complain_on_overflow */ + mips_switch_reloc, /* special_function */ + "SWITCH", /* name */ + true, /* partial_inplace */ + 0xffffffff, /* src_mask */ + 0xffffffff, /* dst_mask */ true) /* pcrel_offset */ }; @@ -353,6 +380,19 @@ mips_ecoff_swap_reloc_in (abfd, ext_ptr, intern) >> RELOC_BITS3_TYPE_SH_LITTLE); intern->r_extern = (ext->r_bits[3] & RELOC_BITS3_EXTERN_LITTLE) != 0; } + + /* If this is a MIPS_R_SWITCH reloc, r_symndx is actually the offset + from the reloc address to the base of the difference (see + include/coff/mips.h for more details). We copy symndx into the + r_offset field so as not to confuse ecoff_slurp_reloc_table in + ecoff.c. In adjust_reloc_in we then copy r_offset into the reloc + addend. */ + if (intern->r_type == MIPS_R_SWITCH) + { + BFD_ASSERT (! intern->r_extern); + intern->r_offset = intern->r_symndx; + intern->r_symndx = RELOC_SECTION_TEXT; + } } /* Swap a reloc out. */ @@ -364,25 +404,37 @@ mips_ecoff_swap_reloc_out (abfd, intern, dst) PTR dst; { RELOC *ext = (RELOC *) dst; + long r_symndx; BFD_ASSERT (intern->r_extern || (intern->r_symndx >= 0 && intern->r_symndx <= 12)); + /* If this is a MIPS_R_SWITCH reloc, we actually want to write the + contents of r_offset out as the symbol index. This undoes the + change made by mips_ecoff_swap_reloc_in. */ + if (intern->r_type != MIPS_R_SWITCH) + r_symndx = intern->r_symndx; + else + { + BFD_ASSERT (intern->r_symndx == RELOC_SECTION_TEXT); + r_symndx = intern->r_offset; + } + bfd_h_put_32 (abfd, intern->r_vaddr, (bfd_byte *) ext->r_vaddr); if (abfd->xvec->header_byteorder_big_p != false) { - ext->r_bits[0] = intern->r_symndx >> RELOC_BITS0_SYMNDX_SH_LEFT_BIG; - ext->r_bits[1] = intern->r_symndx >> RELOC_BITS1_SYMNDX_SH_LEFT_BIG; - ext->r_bits[2] = intern->r_symndx >> RELOC_BITS2_SYMNDX_SH_LEFT_BIG; + ext->r_bits[0] = r_symndx >> RELOC_BITS0_SYMNDX_SH_LEFT_BIG; + ext->r_bits[1] = r_symndx >> RELOC_BITS1_SYMNDX_SH_LEFT_BIG; + ext->r_bits[2] = r_symndx >> RELOC_BITS2_SYMNDX_SH_LEFT_BIG; ext->r_bits[3] = (((intern->r_type << RELOC_BITS3_TYPE_SH_BIG) & RELOC_BITS3_TYPE_BIG) | (intern->r_extern ? RELOC_BITS3_EXTERN_BIG : 0)); } else { - ext->r_bits[0] = intern->r_symndx >> RELOC_BITS0_SYMNDX_SH_LEFT_LITTLE; - ext->r_bits[1] = intern->r_symndx >> RELOC_BITS1_SYMNDX_SH_LEFT_LITTLE; - ext->r_bits[2] = intern->r_symndx >> RELOC_BITS2_SYMNDX_SH_LEFT_LITTLE; + ext->r_bits[0] = r_symndx >> RELOC_BITS0_SYMNDX_SH_LEFT_LITTLE; + ext->r_bits[1] = r_symndx >> RELOC_BITS1_SYMNDX_SH_LEFT_LITTLE; + ext->r_bits[2] = r_symndx >> RELOC_BITS2_SYMNDX_SH_LEFT_LITTLE; ext->r_bits[3] = (((intern->r_type << RELOC_BITS3_TYPE_SH_LITTLE) & RELOC_BITS3_TYPE_LITTLE) | (intern->r_extern ? RELOC_BITS3_EXTERN_LITTLE : 0)); @@ -399,7 +451,7 @@ mips_adjust_reloc_in (abfd, intern, rptr) const struct internal_reloc *intern; arelent *rptr; { - if (intern->r_type > MIPS_R_PCREL16) + if (intern->r_type > MIPS_R_SWITCH) abort (); if (! intern->r_extern @@ -412,6 +464,14 @@ mips_adjust_reloc_in (abfd, intern, rptr) if (intern->r_type == MIPS_R_IGNORE) rptr->sym_ptr_ptr = bfd_abs_section.symbol_ptr_ptr; + /* If this is a MIPS_R_SWITCH reloc, we want the addend field of the + BFD relocto hold the value which was originally in the symndx + field of the internal MIPS ECOFF reloc. This value was copied + into intern->r_offset by mips_swap_reloc_in, and here we copy it + into the addend field. */ + if (intern->r_type == MIPS_R_SWITCH) + rptr->addend = intern->r_offset; + rptr->howto = &mips_howto_table[intern->r_type]; } @@ -424,6 +484,12 @@ mips_adjust_reloc_out (abfd, rel, intern) const arelent *rel; struct internal_reloc *intern; { + /* For a MIPS_R_SWITCH reloc we must copy rel->addend into + intern->r_offset. This will then be written out as the symbol + index by mips_ecoff_swap_reloc_out. This operation parallels the + action of mips_adjust_reloc_in. */ + if (intern->r_type == MIPS_R_SWITCH) + intern->r_offset = rel->addend; } /* ECOFF relocs are either against external symbols, or against @@ -724,6 +790,31 @@ mips_gprel_reloc (abfd, return bfd_reloc_ok; } +/* This is the special function for the MIPS_R_SWITCH reloc. This + special reloc is normally correct in the object file, and only + requires special handling when relaxing. We don't want + bfd_perform_relocation to tamper with it at all. */ + +/*ARGSUSED*/ +static bfd_reloc_status_type +mips_switch_reloc (abfd, + reloc_entry, + symbol, + data, + input_section, + output_bfd, + error_message) + bfd *abfd; + arelent *reloc_entry; + asymbol *symbol; + PTR data; + asection *input_section; + bfd *output_bfd; + char **error_message; +{ + return bfd_reloc_ok; +} + /* Get the howto structure for a generic reloc type. */ static CONST struct reloc_howto_struct * @@ -760,6 +851,9 @@ mips_bfd_reloc_type_lookup (abfd, code) case BFD_RELOC_16_PCREL_S2: mips_type = MIPS_R_PCREL16; break; + case BFD_RELOC_GPREL32: + mips_type = MIPS_R_SWITCH; + break; default: return (CONST struct reloc_howto_struct *) NULL; } @@ -938,6 +1032,32 @@ mips_relocate_section (output_bfd, info, input_bfd, input_section, howto = &mips_howto_table[int_rel.r_type]; + /* The SWITCH reloc must be handled specially. This reloc is + marks the location of a difference between two portions of an + object file. The symbol index does not reference a symbol, + but is actually the offset from the reloc to the subtrahend + of the difference. This reloc is correct in the object file, + and needs no further adjustment, unless we are relaxing. If + we are relaxing, we may have to add in an offset. Since no + symbols are involved in this reloc, we handle it completely + here. */ + if (int_rel.r_type == MIPS_R_SWITCH) + { + if (offsets != NULL + && offsets[i] != 0) + { + r = _bfd_relocate_contents (howto, input_bfd, + (bfd_vma) offsets[i], + (contents + + adjust + + int_rel.r_vaddr + - input_section->vma)); + BFD_ASSERT (r == bfd_reloc_ok); + } + + continue; + } + if (int_rel.r_extern) { h = sym_hashes[int_rel.r_symndx]; @@ -1532,60 +1652,105 @@ mips_relax_section (abfd, sec, info, again) offsets[i] = 1; - /* Now look for all PC relative branches that cross this reloc - and adjust their offsets. We will turn the single branch - instruction into a four instruction sequence. In this loop - we are only interested in local PC relative branches. */ + /* Now look for all PC relative branches or switch table entries + that cross this reloc and adjust their offsets. We will turn + the single branch instruction into a four instruction + sequence. In this loop we are only interested in local PC + relative branches. */ adj_ext_rel = (struct external_reloc *) section_tdata->external_relocs; for (adj_i = 0; adj_ext_rel < ext_rel_end; adj_ext_rel++, adj_i++) { + int r_type; struct internal_reloc adj_int_rel; - unsigned long insn; - bfd_vma dst; - /* Quickly check that this reloc is internal PCREL16. */ + /* Quickly check that this reloc is internal PCREL16 or + SWITCH. */ if (abfd->xvec->header_byteorder_big_p) { - if ((adj_ext_rel->r_bits[3] & RELOC_BITS3_EXTERN_BIG) != 0 - || (((adj_ext_rel->r_bits[3] & RELOC_BITS3_TYPE_BIG) - >> RELOC_BITS3_TYPE_SH_BIG) - != MIPS_R_PCREL16)) + if ((adj_ext_rel->r_bits[3] & RELOC_BITS3_EXTERN_BIG) != 0) + continue; + r_type = ((adj_ext_rel->r_bits[3] & RELOC_BITS3_TYPE_BIG) + >> RELOC_BITS3_TYPE_SH_BIG); + if (r_type != MIPS_R_PCREL16 + && r_type != MIPS_R_SWITCH) continue; } else { - if ((adj_ext_rel->r_bits[3] & RELOC_BITS3_EXTERN_LITTLE) != 0 - || (((adj_ext_rel->r_bits[3] & RELOC_BITS3_TYPE_LITTLE) - >> RELOC_BITS3_TYPE_SH_LITTLE) - != MIPS_R_PCREL16)) + if ((adj_ext_rel->r_bits[3] & RELOC_BITS3_EXTERN_LITTLE) != 0) + continue; + r_type = ((adj_ext_rel->r_bits[3] & RELOC_BITS3_TYPE_LITTLE) + >> RELOC_BITS3_TYPE_SH_LITTLE); + if (r_type != MIPS_R_PCREL16 + && r_type != MIPS_R_SWITCH) continue; } mips_ecoff_swap_reloc_in (abfd, (PTR) adj_ext_rel, &adj_int_rel); - /* We are only interested in a PC relative reloc within this - section. FIXME: Cross section PC relative relocs may not - be handled correctly; does anybody care? */ - if (adj_int_rel.r_symndx != RELOC_SECTION_TEXT) - continue; + if (r_type == MIPS_R_PCREL16) + { + unsigned long insn; + bfd_vma dst; + + /* We are only interested in a PC relative reloc within + this section. FIXME: Cross section PC relative + relocs may not be handled correctly; does anybody + care? */ + if (adj_int_rel.r_symndx != RELOC_SECTION_TEXT) + continue; - /* Fetch the branch instruction. */ - insn = bfd_get_32 (abfd, contents + adj_int_rel.r_vaddr - sec->vma); - - /* Work out the destination address. */ - dst = (insn & 0xffff) << 2; - if ((dst & 0x20000) != 0) - dst -= 0x40000; - dst += adj_int_rel.r_vaddr + 4; - - /* If this branch crosses the branch we just decided to - expand, adjust the offset appropriately. */ - if (adj_int_rel.r_vaddr < int_rel.r_vaddr - && dst > int_rel.r_vaddr) - offsets[adj_i] += PCREL16_EXPANSION_ADJUSTMENT; - else if (adj_int_rel.r_vaddr > int_rel.r_vaddr - && dst <= int_rel.r_vaddr) - offsets[adj_i] -= PCREL16_EXPANSION_ADJUSTMENT; + /* Fetch the branch instruction. */ + insn = bfd_get_32 (abfd, + contents + adj_int_rel.r_vaddr - sec->vma); + + /* Work out the destination address. */ + dst = (insn & 0xffff) << 2; + if ((dst & 0x20000) != 0) + dst -= 0x40000; + dst += adj_int_rel.r_vaddr + 4; + + /* If this branch crosses the branch we just decided to + expand, adjust the offset appropriately. */ + if (adj_int_rel.r_vaddr <= int_rel.r_vaddr + && dst > int_rel.r_vaddr) + offsets[adj_i] += PCREL16_EXPANSION_ADJUSTMENT; + else if (adj_int_rel.r_vaddr > int_rel.r_vaddr + && dst <= int_rel.r_vaddr) + offsets[adj_i] -= PCREL16_EXPANSION_ADJUSTMENT; + } + else + { + bfd_vma start, stop; + + /* A MIPS_R_SWITCH reloc represents a word of the form + .word $L3-$LS12 + The value in the object file is correct, assuming the + original value of $L3. The symndx value is actually + the difference between the reloc address and $LS12. + This lets us compute the original value of $LS12 as + vaddr - symndx + and the original value of $L3 as + vaddr - symndx + addend + where addend is the value from the object file. At + this point, the symndx value is actually found in the + r_offset field, since it was moved by + mips_ecoff_swap_reloc_in. */ + + start = adj_int_rel.r_vaddr - adj_int_rel.r_offset; + stop = start + bfd_get_32 (abfd, + (contents + + adj_int_rel.r_vaddr + - sec->vma)); + + /* The value we want in the object file is stop - start. + If the expanded branch lies between start and stop, + we must adjust the offset. */ + if (start <= int_rel.r_vaddr && stop > int_rel.r_vaddr) + offsets[adj_i] += PCREL16_EXPANSION_ADJUSTMENT; + else if (start > int_rel.r_vaddr && stop <= int_rel.r_vaddr) + offsets[adj_i] -= PCREL16_EXPANSION_ADJUSTMENT; + } } /* Find all symbols in this section defined by this object file |