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* elf64-alpha.c (elf64_alpha_relax_with_lituse): Nop out gpdisp

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following a call to a near function.
This commit is contained in:
Richard Henderson 2001-09-09 20:42:11 +00:00
parent 79bcdb567f
commit 1cd6895c55
2 changed files with 34 additions and 7 deletions
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5
bfd/ChangeLog
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@ -1,3 +1,8 @@
2001-09-09 Richard Henderson <rth@redhat.com>
* elf64-alpha.c (elf64_alpha_relax_with_lituse): Nop out gpdisp
following a call to a near function.
2001-09-08 Richard Henderson <rth@redhat.com>
* elf64-alpha.c (elf64_alpha_relocate_section): Soft fail

36
bfd/elf64-alpha.c
View File

@ -1149,14 +1149,36 @@ elf64_alpha_relax_with_lituse (info, symval, irel, irelend)
else
all_optimized = false;
/* ??? If target gp == current gp we can eliminate the gp reload.
This does depend on every place a gp could be reloaded will
be, which currently happens for all code produced by gcc, but
not necessarily by hand-coded assembly, or if sibling calls
are enabled in gcc.
/* Even if the target is not in range for a direct branch,
if we share a GP, we can eliminate the gp reload. */
if (optdest)
{
Elf_Internal_Rela *gpdisp
= (elf64_alpha_find_reloc_at_ofs
(irel, irelend, urel->r_offset + 4, R_ALPHA_GPDISP));
if (gpdisp)
{
bfd_byte *p_ldah = info->contents + gpdisp->r_offset;
bfd_byte *p_lda = p_ldah + gpdisp->r_addend;
unsigned int ldah = bfd_get_32 (info->abfd, p_ldah);
unsigned int lda = bfd_get_32 (info->abfd, p_lda);
Perhaps conditionalize this on a flag being set in the target
object file's header, and have gcc set it? */
/* Verify that the instruction is "ldah $29,0($26)".
Consider a function that ends in a noreturn call,
and that the next function begins with an ldgp,
and that by accident there is no padding between.
In that case the insn would use $27 as the base. */
if (ldah == 0x27ba0000 && lda == 0x23bd0000)
{
bfd_put_32 (info->abfd, INSN_UNOP, p_ldah);
bfd_put_32 (info->abfd, INSN_UNOP, p_lda);
gpdisp->r_info = ELF64_R_INFO (0, R_ALPHA_NONE);
info->changed_contents = true;
info->changed_relocs = true;
}
}
}
}
break;
}