From fcc76bea372c593cd34dfada143ed5d9baa92997 Mon Sep 17 00:00:00 2001 From: Chris Demetriou Date: Wed, 30 Jan 2002 02:13:20 +0000 Subject: [PATCH] 2002-01-29 Chris Demetriou * elf32-mips.c: Add additional comments about HI16 relocation processing. (_bfd_mips_elf_hi16_reloc): Don't subtract address here for pc-relative relocations. (Reverts change made on 2001-10-31.) (_bfd_mips_elf_lo16_reloc): Subtract address of LO16 part here for pc-relative relocations. (mips_elf_calculate_relocation): Add a comment about a kludge in the R_MIPS_GNU_REL_HI16 handling. (_bfd_mips_elf_relocate_section): Implement that kludge; adjust pc-relative HI16 relocation for difference in HI16 and LO16 addresses, since it can't easily be done in mips_elf_calculate_relocation. --- bfd/ChangeLog | 15 +++++++++++++++ bfd/elf32-mips.c | 35 ++++++++++++++++++++++++++++++----- 2 files changed, 45 insertions(+), 5 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 832bce5..7f6ee72 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,18 @@ +2002-01-29 Chris Demetriou + + * elf32-mips.c: Add additional comments about HI16 relocation + processing. + (_bfd_mips_elf_hi16_reloc): Don't subtract address here for + pc-relative relocations. (Reverts change made on 2001-10-31.) + (_bfd_mips_elf_lo16_reloc): Subtract address of LO16 part here + for pc-relative relocations. + (mips_elf_calculate_relocation): Add a comment about a kludge + in the R_MIPS_GNU_REL_HI16 handling. + (_bfd_mips_elf_relocate_section): Implement that kludge; + adjust pc-relative HI16 relocation for difference in HI16 and + LO16 addresses, since it can't easily be done in + mips_elf_calculate_relocation. + 2002-01-29 Martin Schwidefsky * elf32-i386 (elf_i386_adjust_dynamic_symbol): Do not replace PLT32 diff --git a/bfd/elf32-mips.c b/bfd/elf32-mips.c index bdeed28..5e5a96d 100644 --- a/bfd/elf32-mips.c +++ b/bfd/elf32-mips.c @@ -1640,11 +1640,17 @@ static reloc_howto_type elf_mips_gnu_vtentry_howto = /* Do a R_MIPS_HI16 relocation. This has to be done in combination with a R_MIPS_LO16 reloc, because there is a carry from the LO16 to the HI16. Here we just save the information we need; we do the - actual relocation when we see the LO16. MIPS ELF requires that the - LO16 immediately follow the HI16. As a GNU extension, we permit an + actual relocation when we see the LO16. + + MIPS ELF requires that the LO16 immediately follow the HI16. As a + GNU extension, for non-pc-relative relocations, we permit an arbitrary number of HI16 relocs to be associated with a single LO16 reloc. This extension permits gcc to output the HI and LO relocs - itself. */ + itself. + + This cannot be done for PC-relative relocations because both the HI16 + and LO16 parts of the relocations must be done relative to the LO16 + part, and there can be carry to or borrow from the HI16 part. */ struct mips_hi16 { @@ -1727,8 +1733,6 @@ _bfd_mips_elf_hi16_reloc (abfd, relocation += symbol->section->output_section->vma; relocation += symbol->section->output_offset; relocation += reloc_entry->addend; - if (reloc_entry->howto->pc_relative) - relocation -= reloc_entry->address; if (reloc_entry->address > input_section->_cooked_size) return bfd_reloc_outofrange; @@ -1794,6 +1798,12 @@ _bfd_mips_elf_lo16_reloc (abfd, val = ((insn & 0xffff) << 16) + vallo; val += l->addend; + /* If PC-relative, we need to subtract out the address of the LO + half of the HI/LO. (The actual relocation is relative + to that instruction.) */ + if (reloc_entry->howto->pc_relative) + val -= reloc_entry->address; + /* At this point, "val" has the value of the combined HI/LO pair. If the low order 16 bits (which will be used for the LO16 insn) are negative, then we will need an @@ -6864,6 +6874,11 @@ mips_elf_calculate_relocation (abfd, break; case R_MIPS_GNU_REL_HI16: + /* Instead of subtracting 'p' here, we should be subtracting the + equivalent value for the LO part of the reloc, since the value + here is relative to that address. Because that's not easy to do, + we adjust 'addend' in _bfd_mips_elf_relocate_section(). See also + the comment there for more information. */ value = mips_elf_high (addend + symbol - p); value &= howto->dst_mask; break; @@ -7390,6 +7405,16 @@ _bfd_mips_elf_relocate_section (output_bfd, info, input_bfd, input_section, /* Compute the combined addend. */ addend += l; + + /* If PC-relative, subtract the difference between the + address of the LO part of the reloc and the address of + the HI part. The relocation is relative to the LO + part, but mips_elf_calculate_relocation() doesn't know + it address or the difference from the HI part, so + we subtract that difference here. See also the + comment in mips_elf_calculate_relocation(). */ + if (r_type == R_MIPS_GNU_REL_HI16) + addend -= (lo16_relocation->r_offset - rel->r_offset); } else if (r_type == R_MIPS16_GPREL) { -- 2.7.4