- return true;
-}
-\f
-/* Relax a section when linking a MIPS ECOFF file. This is used for
- embedded PIC code, which always uses PC relative branches which
- only have an 18 bit range on MIPS. If a branch is not in range, we
- generate a long instruction sequence to compensate. Each time we
- find a branch to expand, we have to check all the others again to
- make sure they are still in range. This is slow, but it only has
- to be done when -relax is passed to the linker.
-
- This routine figures out which branches need to expand; the actual
- expansion is done in mips_relocate_section when the section
- contents are relocated. The information is stored in the offsets
- field of the ecoff_section_tdata structure. An offset of 1 means
- that the branch must be expanded into a multi-instruction PC
- relative branch (such an offset will only occur for a PC relative
- branch to an external symbol). Any other offset must be a multiple
- of four, and is the amount to change the branch by (such an offset
- will only occur for a PC relative branch within the same section).
-
- We do not modify the section relocs or contents themselves so that
- if memory usage becomes an issue we can discard them and read them
- again. The only information we must save in memory between this
- routine and the mips_relocate_section routine is the table of
- offsets. */
-
-static boolean
-mips_relax_section (abfd, sec, info, again)
- bfd *abfd;
- asection *sec;
- struct bfd_link_info *info;
- boolean *again;
-{
- struct ecoff_section_tdata *section_tdata;
- bfd_byte *contents = NULL;
- long *offsets;
- struct external_reloc *ext_rel;
- struct external_reloc *ext_rel_end;
- unsigned int i;
-
- /* Assume we are not going to need another pass. */
- *again = false;
-
- /* If we are not generating an ECOFF file, this is much too
- confusing to deal with. */
- if (info->hash->creator->flavour != bfd_get_flavour (abfd))
- return true;
-
- /* If there are no relocs, there is nothing to do. */
- if (sec->reloc_count == 0)
- return true;
-
- /* We are only interested in PC relative relocs, and why would there
- ever be one from anything but the .text section? */
- if (strcmp (bfd_get_section_name (abfd, sec), ".text") != 0)
- return true;
-
- /* Read in the relocs, if we haven't already got them. */
- section_tdata = ecoff_section_data (abfd, sec);
- if (section_tdata == (struct ecoff_section_tdata *) NULL)
- {
- bfd_size_type external_reloc_size;
- bfd_size_type external_relocs_size;
-
- sec->used_by_bfd =
- (PTR) bfd_alloc_by_size_t (abfd, sizeof (struct ecoff_section_tdata));
- if (sec->used_by_bfd == NULL)
- {
- bfd_set_error (bfd_error_no_memory);
- goto error_return;
- }
-
- section_tdata = ecoff_section_data (abfd, sec);
- section_tdata->contents = NULL;
- section_tdata->offsets = NULL;
-
- external_reloc_size = ecoff_backend (abfd)->external_reloc_size;
- external_relocs_size = external_reloc_size * sec->reloc_count;
-
- section_tdata->external_relocs =
- (PTR) bfd_alloc (abfd, external_relocs_size);
- if (section_tdata->external_relocs == NULL && external_relocs_size != 0)
- {
- bfd_set_error (bfd_error_no_memory);
- goto error_return;
- }
-
- if (bfd_seek (abfd, sec->rel_filepos, SEEK_SET) != 0
- || (bfd_read (section_tdata->external_relocs, 1,
- external_relocs_size, abfd)
- != external_relocs_size))
- goto error_return;
-
- /* We must initialize _cooked_size only the first time we are
- called. */
- sec->_cooked_size = sec->_raw_size;
- }
-
- contents = section_tdata->contents;
- offsets = section_tdata->offsets;
-
- /* Look for any external PC relative relocs. Internal PC relative
- relocs are already correct in the object file, so they certainly
- can not overflow. */
- ext_rel = (struct external_reloc *) section_tdata->external_relocs;
- ext_rel_end = ext_rel + sec->reloc_count;
- for (i = 0; ext_rel < ext_rel_end; ext_rel++, i++)
- {
- struct internal_reloc int_rel;
- struct ecoff_link_hash_entry *h;
- asection *hsec;
- bfd_signed_vma relocation;
- struct external_reloc *adj_ext_rel;
- unsigned int adj_i;
- unsigned long ext_count;
- struct ecoff_link_hash_entry **adj_h_ptr;
- struct ecoff_link_hash_entry **adj_h_ptr_end;
- struct ecoff_value_adjust *adjust;
-
- /* If we have already expanded this reloc, we certainly don't
- need to do it again. */
- if (offsets != (long *) NULL && offsets[i] == 1)
- continue;
-
- /* Quickly check that this reloc is external PCREL16. */
- if (abfd->xvec->header_byteorder_big_p)
- {
- if ((ext_rel->r_bits[3] & RELOC_BITS3_EXTERN_BIG) == 0
- || (((ext_rel->r_bits[3] & RELOC_BITS3_TYPE_BIG)
- >> RELOC_BITS3_TYPE_SH_BIG)
- != MIPS_R_PCREL16))
- continue;
- }
- else
- {
- if ((ext_rel->r_bits[3] & RELOC_BITS3_EXTERN_LITTLE) == 0
- || (((ext_rel->r_bits[3] & RELOC_BITS3_TYPE_LITTLE)
- >> RELOC_BITS3_TYPE_SH_LITTLE)
- != MIPS_R_PCREL16))
- continue;
- }
-
- mips_ecoff_swap_reloc_in (abfd, (PTR) ext_rel, &int_rel);
-
- h = ecoff_data (abfd)->sym_hashes[int_rel.r_symndx];
- if (h == (struct ecoff_link_hash_entry *) NULL)
- abort ();
-
- if (h->root.type != bfd_link_hash_defined)
- {
- /* Just ignore undefined symbols. These will presumably
- generate an error later in the link. */
- continue;
- }
-
- /* Get the value of the symbol. */
- hsec = h->root.u.def.section;
- relocation = (h->root.u.def.value
- + hsec->output_section->vma
- + hsec->output_offset);
-
- /* Subtract out the current address. */
- relocation -= (sec->output_section->vma
- + sec->output_offset
- + (int_rel.r_vaddr - sec->vma));
-
- /* The addend is stored in the object file. In the normal case
- of ``bal symbol'', the addend will be -4. It will only be
- different in the case of ``bal symbol+constant''. To avoid
- always reading in the section contents, we don't check the
- addend in the object file (we could easily check the contents
- if we happen to have already read them in, but I fear that
- this could be confusing). This means we will screw up if
- there is a branch to a symbol that is in range, but added to
- a constant which puts it out of range; in such a case the
- link will fail with a reloc overflow error. Since the
- compiler will never generate such code, it should be easy
- enough to work around it by changing the assembly code in the
- source file. */
- relocation -= 4;
-
- /* Now RELOCATION is the number we want to put in the object
- file. See whether it fits. */
- if (relocation >= -0x20000 && relocation < 0x20000)
- continue;
-
- /* Now that we know this reloc needs work, which will rarely
- happen, go ahead and grab the section contents. */
- if (contents == (bfd_byte *) NULL)
- {
- if (info->keep_memory)
- contents = (bfd_byte *) bfd_alloc (abfd, sec->_raw_size);
- else
- contents = (bfd_byte *) malloc (sec->_raw_size);
- if (contents == (bfd_byte *) NULL)
- {
- bfd_set_error (bfd_error_no_memory);
- goto error_return;
- }
- if (! bfd_get_section_contents (abfd, sec, (PTR) contents,
- (file_ptr) 0, sec->_raw_size))
- goto error_return;
- if (info->keep_memory)
- section_tdata->contents = contents;
- }
-
- /* We only support changing the bal instruction. It would be
- possible to handle other PC relative branches, but some of
- them (the conditional branches) would require a different
- length instruction sequence which would complicate both this
- routine and mips_relax_pcrel16. It could be written if
- somebody felt it were important. Ignoring this reloc will
- presumably cause a reloc overflow error later on. */
- if (bfd_get_32 (abfd, contents + int_rel.r_vaddr - sec->vma)
- != 0x0411ffff) /* bgezal $0,. == bal . */
- continue;
-
- /* Bother. We need to expand this reloc, and we will need to
- make another relaxation pass since this change may put other
- relocs out of range. We need to examine the local branches
- and we need to allocate memory to hold the offsets we must
- add to them. We also need to adjust the values of all
- symbols in the object file following this location. */
-
- sec->_cooked_size += PCREL16_EXPANSION_ADJUSTMENT;
- *again = true;
-
- if (offsets == (long *) NULL)
- {
- size_t size;
-
- size = sec->reloc_count * sizeof (long);
- offsets = (long *) bfd_alloc_by_size_t (abfd, size);
- if (offsets == (long *) NULL)
- {
- bfd_set_error (bfd_error_no_memory);
- goto error_return;
- }
- memset (offsets, 0, size);
- section_tdata->offsets = offsets;
- }
-
- 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. */
- 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++)
- {
- struct internal_reloc adj_int_rel;
- unsigned long insn;
- bfd_vma dst;
-
- /* Quickly check that this reloc is internal PCREL16. */
- 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))
- 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))
- 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;
-
- /* 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;
- }
-
- /* Find all symbols in this section defined by this object file
- and adjust their values. Note that we decide whether to
- adjust the value based on the value stored in the ECOFF EXTR
- structure, because the value stored in the hash table may
- have been changed by an earlier expanded reloc and thus may
- no longer correctly indicate whether the symbol is before or
- after the expanded reloc. */
- ext_count = ecoff_data (abfd)->debug_info.symbolic_header.iextMax;
- adj_h_ptr = ecoff_data (abfd)->sym_hashes;
- adj_h_ptr_end = adj_h_ptr + ext_count;
- for (; adj_h_ptr < adj_h_ptr_end; adj_h_ptr++)
- {
- struct ecoff_link_hash_entry *adj_h;
-
- adj_h = *adj_h_ptr;
- if (adj_h != (struct ecoff_link_hash_entry *) NULL
- && adj_h->root.type == bfd_link_hash_defined
- && adj_h->root.u.def.section == sec
- && adj_h->esym.asym.value > int_rel.r_vaddr)
- adj_h->root.u.def.value += PCREL16_EXPANSION_ADJUSTMENT;
- }
-
- /* Add an entry to the symbol value adjust list. This is used
- by bfd_ecoff_debug_accumulate to adjust the values of
- internal symbols and FDR's. */
- adjust = ((struct ecoff_value_adjust *)
- bfd_alloc (abfd, sizeof (struct ecoff_value_adjust)));
- if (adjust == (struct ecoff_value_adjust *) NULL)
- {
- bfd_set_error (bfd_error_no_memory);
- goto error_return;
- }
-
- adjust->start = int_rel.r_vaddr;
- adjust->end = sec->vma + sec->_raw_size;
- adjust->adjust = PCREL16_EXPANSION_ADJUSTMENT;
-
- adjust->next = ecoff_data (abfd)->debug_info.adjust;
- ecoff_data (abfd)->debug_info.adjust = adjust;
- }
-
- if (contents != (bfd_byte *) NULL && ! info->keep_memory)
- free (contents);
-
- return true;
-
- error_return:
- if (contents != (bfd_byte *) NULL && ! info->keep_memory)
- free (contents);
- return false;
-}
-
-/* This routine is called from mips_relocate_section when a PC
- relative reloc must be expanded into the five instruction sequence.
- It handles all the details of the expansion, including resolving
- the reloc. */
-
-static boolean
-mips_relax_pcrel16 (info, input_bfd, input_section, h, location, address)
- struct bfd_link_info *info;
- bfd *input_bfd;
- asection *input_section;
- struct ecoff_link_hash_entry *h;
- bfd_byte *location;
- bfd_vma address;
-{
- bfd_vma relocation;
-
- /* 0x0411ffff is bgezal $0,. == bal . */
- BFD_ASSERT (bfd_get_32 (input_bfd, location) == 0x0411ffff);
-
- /* We need to compute the distance between the symbol and the
- current address plus eight. */
- relocation = (h->root.u.def.value
- + h->root.u.def.section->output_section->vma
- + h->root.u.def.section->output_offset);
- relocation -= address + 8;
-
- /* If the lower half is negative, increment the upper 16 half. */
- if ((relocation & 0x8000) != 0)
- relocation += 0x10000;
-
- bfd_put_32 (input_bfd, 0x04110001, location); /* bal .+8 */
- bfd_put_32 (input_bfd,
- 0x3c010000 | ((relocation >> 16) & 0xffff), /* lui $at,XX */
- location + 4);
- bfd_put_32 (input_bfd,
- 0x24210000 | (relocation & 0xffff), /* addiu $at,$at,XX */
- location + 8);
- bfd_put_32 (input_bfd, 0x003f0821, location + 12); /* addu $at,$at,$ra */
- bfd_put_32 (input_bfd, 0x0020f809, location + 16); /* jalr $at */
-
- return true;