[COMMITTED] Fix alpha-elf relaxation
Richard Henderson
rth@redhat.com
Mon Apr 21 15:58:00 GMT 2014
On 04/21/2014 08:57 AM, Richard Henderson wrote:
> Tested with a gcc bootstrap, which triggered the problem quite easily in
> cc1plus and f951, and committed.
... and now with the patch attached ...
r~
-------------- next part --------------
Fix alpha-elf relaxation
ld/
* emultempl/alphaelf.em (alpha_after_parse): Enable 2 relax passes.
bfd/
* elf64-alpha.c (elf64_alpha_size_got_sections): New may_merge
parameter; honor it and disable got merging when false.
(elf64_alpha_relax_got_load): Do not relax to GPREL relocs during
the first pass of relaxation.
(elf64_alpha_relax_with_lituse): Likewise. Move relaxed relocs to
the end of the LITERAL+LITUSE chain.
(elf64_alpha_relax_section): Only process LITERAL relocs during the
second pass of relaxation.
diff --git a/bfd/elf64-alpha.c b/bfd/elf64-alpha.c
index c9876fb..073e578 100644
--- a/bfd/elf64-alpha.c
+++ b/bfd/elf64-alpha.c
@@ -2466,7 +2466,8 @@ elf64_alpha_calc_got_offsets (struct bfd_link_info *info)
/* Constructs the gots. */
static bfd_boolean
-elf64_alpha_size_got_sections (struct bfd_link_info *info)
+elf64_alpha_size_got_sections (struct bfd_link_info *info,
+ bfd_boolean may_merge)
{
bfd *i, *got_list, *cur_got_obj = NULL;
struct alpha_elf_link_hash_table * htab;
@@ -2521,21 +2522,24 @@ elf64_alpha_size_got_sections (struct bfd_link_info *info)
if (cur_got_obj == NULL)
return FALSE;
- i = alpha_elf_tdata(cur_got_obj)->got_link_next;
- while (i != NULL)
+ if (may_merge)
{
- if (elf64_alpha_can_merge_gots (cur_got_obj, i))
+ i = alpha_elf_tdata(cur_got_obj)->got_link_next;
+ while (i != NULL)
{
- elf64_alpha_merge_gots (cur_got_obj, i);
+ if (elf64_alpha_can_merge_gots (cur_got_obj, i))
+ {
+ elf64_alpha_merge_gots (cur_got_obj, i);
- alpha_elf_tdata(i)->got->size = 0;
- i = alpha_elf_tdata(i)->got_link_next;
- alpha_elf_tdata(cur_got_obj)->got_link_next = i;
- }
- else
- {
- cur_got_obj = i;
- i = alpha_elf_tdata(i)->got_link_next;
+ alpha_elf_tdata(i)->got->size = 0;
+ i = alpha_elf_tdata(i)->got_link_next;
+ alpha_elf_tdata(cur_got_obj)->got_link_next = i;
+ }
+ else
+ {
+ cur_got_obj = i;
+ i = alpha_elf_tdata(i)->got_link_next;
+ }
}
}
@@ -2638,7 +2642,7 @@ elf64_alpha_always_size_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
if (htab == NULL)
return FALSE;
- if (!elf64_alpha_size_got_sections (info))
+ if (!elf64_alpha_size_got_sections (info, TRUE))
return FALSE;
/* Allocate space for all of the .got subsections. */
@@ -3074,6 +3078,10 @@ elf64_alpha_relax_got_load (struct alpha_relax_info *info, bfd_vma symval,
}
else
{
+ /* We may only create GPREL relocs during the second pass. */
+ if (info->link_info->relax_pass == 0)
+ return TRUE;
+
disp = symval - info->gp;
insn = (OP_LDA << 26) | (insn & 0x03ff0000);
r_type = R_ALPHA_GPREL16;
@@ -3214,21 +3222,27 @@ static bfd_boolean
elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
bfd_vma symval, Elf_Internal_Rela *irel)
{
- Elf_Internal_Rela *urel, *irelend = info->relend;
- int flags, count, i;
+ Elf_Internal_Rela *urel, *erel, *irelend = info->relend;
+ int flags;
bfd_signed_vma disp;
bfd_boolean fits16;
bfd_boolean fits32;
bfd_boolean lit_reused = FALSE;
bfd_boolean all_optimized = TRUE;
+ bfd_boolean changed_contents;
+ bfd_boolean changed_relocs;
+ bfd_byte *contents = info->contents;
+ bfd *abfd = info->abfd;
+ bfd_vma sec_output_vma;
unsigned int lit_insn;
+ int relax_pass;
- lit_insn = bfd_get_32 (info->abfd, info->contents + irel->r_offset);
+ lit_insn = bfd_get_32 (abfd, contents + irel->r_offset);
if (lit_insn >> 26 != OP_LDQ)
{
((*_bfd_error_handler)
("%B: %A+0x%lx: warning: LITERAL relocation against unexpected insn",
- info->abfd, info->sec,
+ abfd, info->sec,
(unsigned long) irel->r_offset));
return TRUE;
}
@@ -3237,25 +3251,32 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
if (alpha_elf_dynamic_symbol_p (&info->h->root, info->link_info))
return TRUE;
+ changed_contents = info->changed_contents;
+ changed_relocs = info->changed_relocs;
+ sec_output_vma = info->sec->output_section->vma + info->sec->output_offset;
+ relax_pass = info->link_info->relax_pass;
+
/* Summarize how this particular LITERAL is used. */
- for (urel = irel+1, flags = count = 0; urel < irelend; ++urel, ++count)
+ for (erel = irel+1, flags = 0; erel < irelend; ++erel)
{
- if (ELF64_R_TYPE (urel->r_info) != R_ALPHA_LITUSE)
+ if (ELF64_R_TYPE (erel->r_info) != R_ALPHA_LITUSE)
break;
- if (urel->r_addend <= 6)
- flags |= 1 << urel->r_addend;
+ if (erel->r_addend <= 6)
+ flags |= 1 << erel->r_addend;
}
/* A little preparation for the loop... */
disp = symval - info->gp;
- for (urel = irel+1, i = 0; i < count; ++i, ++urel)
+ for (urel = irel+1; urel < erel; ++urel)
{
+ bfd_vma urel_r_offset = urel->r_offset;
unsigned int insn;
int insn_disp;
bfd_signed_vma xdisp;
+ Elf_Internal_Rela nrel;
- insn = bfd_get_32 (info->abfd, info->contents + urel->r_offset);
+ insn = bfd_get_32 (abfd, contents + urel_r_offset);
switch (urel->r_addend)
{
@@ -3267,6 +3288,13 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
break;
case LITUSE_ALPHA_BASE:
+ /* We may only create GPREL relocs during the second pass. */
+ if (relax_pass == 0)
+ {
+ all_optimized = FALSE;
+ break;
+ }
+
/* We can always optimize 16-bit displacements. */
/* Extract the displacement from the instruction, sign-extending
@@ -3284,14 +3312,20 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
/* Take the op code and dest from this insn, take the base
register from the literal insn. Leave the offset alone. */
insn = (insn & 0xffe0ffff) | (lit_insn & 0x001f0000);
- urel->r_info = ELF64_R_INFO (ELF64_R_SYM (irel->r_info),
- R_ALPHA_GPREL16);
- urel->r_addend = irel->r_addend;
- info->changed_relocs = TRUE;
-
- bfd_put_32 (info->abfd, (bfd_vma) insn,
- info->contents + urel->r_offset);
- info->changed_contents = TRUE;
+ bfd_put_32 (abfd, (bfd_vma) insn, contents + urel_r_offset);
+ changed_contents = TRUE;
+
+ nrel = *urel;
+ nrel.r_info = ELF64_R_INFO (ELF64_R_SYM (irel->r_info),
+ R_ALPHA_GPREL16);
+ nrel.r_addend = irel->r_addend;
+
+ /* As we adjust, move the reloc to the end so that we don't
+ break the LITERAL+LITUSE chain. */
+ if (urel < --erel)
+ *urel-- = *erel;
+ *erel = nrel;
+ changed_relocs = TRUE;
}
/* If all mem+byte, we can optimize 32-bit mem displacements. */
@@ -3302,15 +3336,16 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
irel->r_info = ELF64_R_INFO (ELF64_R_SYM (irel->r_info),
R_ALPHA_GPRELHIGH);
lit_insn = (OP_LDAH << 26) | (lit_insn & 0x03ff0000);
- bfd_put_32 (info->abfd, (bfd_vma) lit_insn,
- info->contents + irel->r_offset);
+ bfd_put_32 (abfd, (bfd_vma) lit_insn, contents + irel->r_offset);
lit_reused = TRUE;
- info->changed_contents = TRUE;
+ changed_contents = TRUE;
+ /* Since all relocs must be optimized, don't bother swapping
+ this relocation to the end. */
urel->r_info = ELF64_R_INFO (ELF64_R_SYM (irel->r_info),
R_ALPHA_GPRELLOW);
urel->r_addend = irel->r_addend;
- info->changed_relocs = TRUE;
+ changed_relocs = TRUE;
}
else
all_optimized = FALSE;
@@ -3324,14 +3359,19 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
insn &= ~ (unsigned) 0x001ff000;
insn |= ((symval & 7) << 13) | 0x1000;
-
- urel->r_info = ELF64_R_INFO (0, R_ALPHA_NONE);
- urel->r_addend = 0;
- info->changed_relocs = TRUE;
-
- bfd_put_32 (info->abfd, (bfd_vma) insn,
- info->contents + urel->r_offset);
- info->changed_contents = TRUE;
+ bfd_put_32 (abfd, (bfd_vma) insn, contents + urel_r_offset);
+ changed_contents = TRUE;
+
+ nrel = *urel;
+ nrel.r_info = ELF64_R_INFO (0, R_ALPHA_NONE);
+ nrel.r_addend = 0;
+
+ /* As we adjust, move the reloc to the end so that we don't
+ break the LITERAL+LITUSE chain. */
+ if (urel < --erel)
+ *urel-- = *erel;
+ *erel = nrel;
+ changed_relocs = TRUE;
break;
case LITUSE_ALPHA_JSR:
@@ -3348,18 +3388,15 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
if (info->h && info->h->root.root.type == bfd_link_hash_undefweak)
{
insn |= 31 << 16;
- bfd_put_32 (info->abfd, (bfd_vma) insn,
- info->contents + urel->r_offset);
+ bfd_put_32 (abfd, (bfd_vma) insn, contents + urel_r_offset);
- info->changed_contents = TRUE;
+ changed_contents = TRUE;
break;
}
/* If not zero, place to jump without needing pv. */
optdest = elf64_alpha_relax_opt_call (info, symval);
- org = (info->sec->output_section->vma
- + info->sec->output_offset
- + urel->r_offset + 4);
+ org = sec_output_vma + urel_r_offset + 4;
odisp = (optdest ? optdest : symval) - org;
if (odisp >= -0x400000 && odisp < 0x400000)
@@ -3371,27 +3408,32 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
insn = (OP_BSR << 26) | (insn & 0x03e00000);
else
insn = (OP_BR << 26) | (insn & 0x03e00000);
+ bfd_put_32 (abfd, (bfd_vma) insn, contents + urel_r_offset);
+ changed_contents = TRUE;
- urel->r_info = ELF64_R_INFO (ELF64_R_SYM (irel->r_info),
- R_ALPHA_BRADDR);
- urel->r_addend = irel->r_addend;
+ nrel = *urel;
+ nrel.r_info = ELF64_R_INFO (ELF64_R_SYM (irel->r_info),
+ R_ALPHA_BRADDR);
+ nrel.r_addend = irel->r_addend;
if (optdest)
- urel->r_addend += optdest - symval;
+ nrel.r_addend += optdest - symval;
else
all_optimized = FALSE;
- bfd_put_32 (info->abfd, (bfd_vma) insn,
- info->contents + urel->r_offset);
-
/* Kill any HINT reloc that might exist for this insn. */
xrel = (elf64_alpha_find_reloc_at_ofs
- (info->relocs, info->relend, urel->r_offset,
+ (info->relocs, info->relend, urel_r_offset,
R_ALPHA_HINT));
if (xrel)
xrel->r_info = ELF64_R_INFO (0, R_ALPHA_NONE);
- info->changed_contents = TRUE;
+ /* As we adjust, move the reloc to the end so that we don't
+ break the LITERAL+LITUSE chain. */
+ if (urel < --erel)
+ *urel-- = *erel;
+ *erel = nrel;
+
info->changed_relocs = TRUE;
}
else
@@ -3403,14 +3445,14 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
{
Elf_Internal_Rela *gpdisp
= (elf64_alpha_find_reloc_at_ofs
- (info->relocs, irelend, urel->r_offset + 4,
+ (info->relocs, irelend, urel_r_offset + 4,
R_ALPHA_GPDISP));
if (gpdisp)
{
- bfd_byte *p_ldah = info->contents + gpdisp->r_offset;
+ bfd_byte *p_ldah = 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);
+ unsigned int ldah = bfd_get_32 (abfd, p_ldah);
+ unsigned int lda = bfd_get_32 (abfd, p_lda);
/* Verify that the instruction is "ldah $29,0($26)".
Consider a function that ends in a noreturn call,
@@ -3419,12 +3461,12 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
In that case the insn would use $27 as the base. */
if (ldah == 0x27ba0000 && lda == 0x23bd0000)
{
- bfd_put_32 (info->abfd, (bfd_vma) INSN_UNOP, p_ldah);
- bfd_put_32 (info->abfd, (bfd_vma) INSN_UNOP, p_lda);
+ bfd_put_32 (abfd, (bfd_vma) INSN_UNOP, p_ldah);
+ bfd_put_32 (abfd, (bfd_vma) INSN_UNOP, p_lda);
gpdisp->r_info = ELF64_R_INFO (0, R_ALPHA_NONE);
- info->changed_contents = TRUE;
- info->changed_relocs = TRUE;
+ changed_contents = TRUE;
+ changed_relocs = TRUE;
}
}
}
@@ -3433,6 +3475,9 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
}
}
+ /* If we reused the literal instruction, we must have optimized all. */
+ BFD_ASSERT(!lit_reused || all_optimized);
+
/* If all cases were optimized, we can reduce the use count on this
got entry by one, possibly eliminating it. */
if (all_optimized)
@@ -3452,17 +3497,19 @@ elf64_alpha_relax_with_lituse (struct alpha_relax_info *info,
if (!lit_reused)
{
irel->r_info = ELF64_R_INFO (0, R_ALPHA_NONE);
- info->changed_relocs = TRUE;
+ changed_relocs = TRUE;
- bfd_put_32 (info->abfd, (bfd_vma) INSN_UNOP,
- info->contents + irel->r_offset);
- info->changed_contents = TRUE;
+ bfd_put_32 (abfd, (bfd_vma) INSN_UNOP, contents + irel->r_offset);
+ changed_contents = TRUE;
}
-
- return TRUE;
}
- else
- return elf64_alpha_relax_got_load (info, symval, irel, R_ALPHA_LITERAL);
+
+ info->changed_contents = changed_contents;
+ info->changed_relocs = changed_relocs;
+
+ if (all_optimized || relax_pass == 0)
+ return TRUE;
+ return elf64_alpha_relax_got_load (info, symval, irel, R_ALPHA_LITERAL);
}
static bfd_boolean
@@ -3724,6 +3771,7 @@ elf64_alpha_relax_section (bfd *abfd, asection *sec,
struct alpha_elf_got_entry **local_got_entries;
struct alpha_relax_info info;
struct alpha_elf_link_hash_table * htab;
+ int relax_pass;
htab = alpha_elf_hash_table (link_info);
if (htab == NULL)
@@ -3739,15 +3787,19 @@ elf64_alpha_relax_section (bfd *abfd, asection *sec,
return TRUE;
BFD_ASSERT (is_alpha_elf (abfd));
+ relax_pass = link_info->relax_pass;
/* Make sure our GOT and PLT tables are up-to-date. */
if (htab->relax_trip != link_info->relax_trip)
{
htab->relax_trip = link_info->relax_trip;
- /* This should never fail after the initial round, since the only
- error is GOT overflow, and relaxation only shrinks the table. */
- if (!elf64_alpha_size_got_sections (link_info))
+ /* This should never fail after the initial round, since the only error
+ is GOT overflow, and relaxation only shrinks the table. However, we
+ may only merge got sections during the first pass. If we merge
+ sections after we've created GPREL relocs, the GP for the merged
+ section backs up which may put the relocs out of range. */
+ if (!elf64_alpha_size_got_sections (link_info, relax_pass == 0))
abort ();
if (elf_hash_table (link_info)->dynamic_sections_created)
{
@@ -3802,24 +3854,21 @@ elf64_alpha_relax_section (bfd *abfd, asection *sec,
unsigned long r_symndx = ELF64_R_SYM (irel->r_info);
/* Early exit for unhandled or unrelaxable relocations. */
- switch (r_type)
- {
- case R_ALPHA_LITERAL:
- case R_ALPHA_GPRELHIGH:
- case R_ALPHA_GPRELLOW:
- case R_ALPHA_GOTDTPREL:
- case R_ALPHA_GOTTPREL:
- case R_ALPHA_TLSGD:
- break;
-
- case R_ALPHA_TLSLDM:
- /* The symbol for a TLSLDM reloc is ignored. Collapse the
- reloc to the STN_UNDEF (0) symbol so that they all match. */
- r_symndx = STN_UNDEF;
- break;
-
- default:
- continue;
+ if (r_type != R_ALPHA_LITERAL)
+ {
+ /* We complete everything except LITERAL in the first pass. */
+ if (relax_pass != 0)
+ continue;
+ if (r_type == R_ALPHA_TLSLDM)
+ {
+ /* The symbol for a TLSLDM reloc is ignored. Collapse the
+ reloc to the STN_UNDEF (0) symbol so that they all match. */
+ r_symndx = STN_UNDEF;
+ }
+ else if (r_type != R_ALPHA_GOTDTPREL
+ && r_type != R_ALPHA_GOTTPREL
+ && r_type != R_ALPHA_TLSGD)
+ continue;
}
/* Get the value of the symbol referred to by the reloc. */
diff --git a/ld/emultempl/alphaelf.em b/ld/emultempl/alphaelf.em
index 091ef66..a36fc7d 100644
--- a/ld/emultempl/alphaelf.em
+++ b/ld/emultempl/alphaelf.em
@@ -72,6 +72,7 @@ alpha_after_open (void)
static void
alpha_after_parse (void)
{
+ link_info.relax_pass = 2;
if (limit_32bit && !link_info.shared && !link_info.relocatable)
lang_section_start (".interp",
exp_binop ('+',
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