From: Bob Wilson <bwilson@tensilica.com>
To: binutils@sources.redhat.com
Subject: fix Xtensa property tables with relaxation and --gc-sections
Date: Thu, 12 Apr 2007 19:13:00 -0000 [thread overview]
Message-ID: <461E827B.7090907@tensilica.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 1609 bytes --]
My previous change to keep the Xtensa property tables from being GC'ed exposed
another problem. If the first entry in a property table is removed by the
linker's relaxation, the relocation for the entry was getting its offset set to
a negative value. The subsequent call to elf_xtensa_discard_info_for_section
was compounding the problem by neglecting to sort the relocations. (They should
normally be sorted following relaxation, but relaxation is not always enabled.)
While working on this, I decided to make the relaxation code more robust with
regard to relocations on the property table entries, and I also added some new
predicates to check for the various kinds of property tables. Tested with the
testsuite for an xtensa-elf target, and by building "busybox" for
xtensa-linux-gnu. Committed on the mainline.
bfd/
* elf32-xtensa.c (xtensa_is_insntable_section): New.
(xtensa_is_proptable_section): New.
(elf_xtensa_discard_info_for_section): Handle "full" .xt.prop property
tables with 12-byte entries, as well as tables with 8-byte entries.
Sort the relocations before examining them.
(relax_property_section): Use xtensa_is_proptable_section and
xtensa_is_littable_section. Rewrite code for combining table entries
to be more robust in case of unexpected relocations. Do not set offset
of unused relocations to less than zero.
(xtensa_is_property_section): Use other functions instead of
duplicating section name comparisons.
(xtensa_is_littable_section): Use CONST_STRNEQ for ".gnu.linkonce.p.".
(xtensa_get_property_predef_flags): Use xtensa_is_insntable_section.
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Index: elf32-xtensa.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-xtensa.c,v
retrieving revision 1.84
diff -u -p -r1.84 elf32-xtensa.c
--- elf32-xtensa.c 12 Apr 2007 15:52:02 -0000 1.84
+++ elf32-xtensa.c 12 Apr 2007 15:57:44 -0000
@@ -103,7 +103,9 @@ static bfd_vma get_elf_r_symndx_offset (
static bfd_boolean is_reloc_sym_weak (bfd *, Elf_Internal_Rela *);
static bfd_boolean pcrel_reloc_fits (xtensa_opcode, int, bfd_vma, bfd_vma);
static bfd_boolean xtensa_is_property_section (asection *);
+static bfd_boolean xtensa_is_insntable_section (asection *);
static bfd_boolean xtensa_is_littable_section (asection *);
+static bfd_boolean xtensa_is_proptable_section (asection *);
static int internal_reloc_compare (const void *, const void *);
static int internal_reloc_matches (const void *, const void *);
extern asection *xtensa_get_property_section (asection *, const char *);
@@ -2829,16 +2831,22 @@ elf_xtensa_discard_info_for_section (bfd
bfd_byte *contents;
bfd_vma section_size;
bfd_vma offset, actual_offset;
- size_t removed_bytes = 0;
-
- section_size = sec->size;
- if (section_size == 0 || section_size % 8 != 0)
- return FALSE;
+ bfd_size_type removed_bytes = 0;
+ bfd_size_type entry_size;
if (sec->output_section
&& bfd_is_abs_section (sec->output_section))
return FALSE;
+ if (xtensa_is_proptable_section (sec))
+ entry_size = 12;
+ else
+ entry_size = 8;
+
+ section_size = sec->size;
+ if (section_size == 0 || section_size % entry_size != 0)
+ return FALSE;
+
contents = retrieve_contents (abfd, sec, info->keep_memory);
if (!contents)
return FALSE;
@@ -2850,10 +2858,15 @@ elf_xtensa_discard_info_for_section (bfd
return FALSE;
}
+ /* Sort the relocations. They should already be in order when
+ relaxation is enabled, but it might not be. */
+ qsort (cookie->rels, sec->reloc_count, sizeof (Elf_Internal_Rela),
+ internal_reloc_compare);
+
cookie->rel = cookie->rels;
cookie->relend = cookie->rels + sec->reloc_count;
- for (offset = 0; offset < section_size; offset += 8)
+ for (offset = 0; offset < section_size; offset += entry_size)
{
actual_offset = offset - removed_bytes;
@@ -2877,11 +2890,11 @@ elf_xtensa_discard_info_for_section (bfd
if (ELF32_R_TYPE (cookie->rel->r_info) != R_XTENSA_NONE)
{
/* Shift the contents up. */
- if (offset + 8 < section_size)
+ if (offset + entry_size < section_size)
memmove (&contents[actual_offset],
- &contents[actual_offset+8],
- section_size - offset - 8);
- removed_bytes += 8;
+ &contents[actual_offset + entry_size],
+ section_size - offset - entry_size);
+ removed_bytes += entry_size;
}
/* Remove this relocation. */
@@ -8840,12 +8853,13 @@ relax_property_section (bfd *abfd,
{
Elf_Internal_Rela *internal_relocs;
bfd_byte *contents;
- unsigned i, nexti;
+ unsigned i;
bfd_boolean ok = TRUE;
bfd_boolean is_full_prop_section;
size_t last_zfill_target_offset = 0;
asection *last_zfill_target_sec = NULL;
bfd_size_type sec_size;
+ bfd_size_type entry_size;
sec_size = bfd_get_section_limit (abfd, sec);
internal_relocs = retrieve_internal_relocs (abfd, sec,
@@ -8857,9 +8871,11 @@ relax_property_section (bfd *abfd,
goto error_return;
}
- is_full_prop_section =
- ( CONST_STRNEQ (sec->name, XTENSA_PROP_SEC_NAME)
- || CONST_STRNEQ (sec->name, ".gnu.linkonce.prop."));
+ is_full_prop_section = xtensa_is_proptable_section (sec);
+ if (is_full_prop_section)
+ entry_size = 12;
+ else
+ entry_size = 8;
if (internal_relocs)
{
@@ -8888,12 +8904,8 @@ relax_property_section (bfd *abfd,
size_p = &contents[irel->r_offset + 4];
flags_p = NULL;
if (is_full_prop_section)
- {
- flags_p = &contents[irel->r_offset + 8];
- BFD_ASSERT (irel->r_offset + 12 <= sec_size);
- }
- else
- BFD_ASSERT (irel->r_offset + 8 <= sec_size);
+ flags_p = &contents[irel->r_offset + 8];
+ BFD_ASSERT (irel->r_offset + entry_size <= sec_size);
target_sec = r_reloc_get_section (&val.r_rel);
target_relax_info = get_xtensa_relax_info (target_sec);
@@ -8977,74 +8989,106 @@ relax_property_section (bfd *abfd,
reclaim the space in the output section, so we do this twice. */
if (internal_relocs && (!link_info->relocatable
- || strcmp (sec->name, XTENSA_LIT_SEC_NAME) == 0))
+ || xtensa_is_littable_section (sec)))
{
Elf_Internal_Rela *last_irel = NULL;
+ Elf_Internal_Rela *irel, *next_rel, *rel_end;
int removed_bytes = 0;
- bfd_vma offset, last_irel_offset;
+ bfd_vma offset;
bfd_vma section_size;
- bfd_size_type entry_size;
flagword predef_flags;
- if (is_full_prop_section)
- entry_size = 12;
- else
- entry_size = 8;
-
predef_flags = xtensa_get_property_predef_flags (sec);
- /* Walk over memory and irels at the same time.
+ /* Walk over memory and relocations at the same time.
This REQUIRES that the internal_relocs be sorted by offset. */
qsort (internal_relocs, sec->reloc_count, sizeof (Elf_Internal_Rela),
internal_reloc_compare);
- nexti = 0; /* Index into internal_relocs. */
pin_internal_relocs (sec, internal_relocs);
pin_contents (sec, contents);
- last_irel_offset = (bfd_vma) -1;
+ next_rel = internal_relocs;
+ rel_end = internal_relocs + sec->reloc_count;
+
section_size = sec->size;
BFD_ASSERT (section_size % entry_size == 0);
for (offset = 0; offset < section_size; offset += entry_size)
{
- Elf_Internal_Rela *irel, *next_irel;
+ Elf_Internal_Rela *offset_rel, *extra_rel;
bfd_vma bytes_to_remove, size, actual_offset;
- bfd_boolean remove_this_irel;
+ bfd_boolean remove_this_rel;
flagword flags;
- irel = NULL;
- next_irel = NULL;
-
- /* Find the next two relocations (if there are that many left),
- skipping over any R_XTENSA_NONE relocs. On entry, "nexti" is
- the starting reloc index. After these two loops, "i"
- is the index of the first non-NONE reloc past that starting
- index, and "nexti" is the index for the next non-NONE reloc
- after "i". */
+ /* Find the first relocation for the entry at the current offset.
+ Adjust the offsets of any extra relocations for the previous
+ entry. */
+ offset_rel = NULL;
+ if (next_rel)
+ {
+ for (irel = next_rel; irel < rel_end; irel++)
+ {
+ if ((irel->r_offset == offset
+ && ELF32_R_TYPE (irel->r_info) != R_XTENSA_NONE)
+ || irel->r_offset > offset)
+ {
+ offset_rel = irel;
+ break;
+ }
+ irel->r_offset -= removed_bytes;
+ irel++;
+ }
+ }
- for (i = nexti; i < sec->reloc_count; i++)
+ /* Find the next relocation (if there are any left). */
+ extra_rel = NULL;
+ if (offset_rel)
{
- if (ELF32_R_TYPE (internal_relocs[i].r_info) != R_XTENSA_NONE)
+ for (irel = offset_rel + 1; irel < rel_end; irel++)
{
- irel = &internal_relocs[i];
- break;
+ if (ELF32_R_TYPE (irel->r_info) != R_XTENSA_NONE)
+ {
+ extra_rel = irel;
+ break;
+ }
}
- internal_relocs[i].r_offset -= removed_bytes;
}
- for (nexti = i + 1; nexti < sec->reloc_count; nexti++)
+ /* Check if there are relocations on the current entry. There
+ should usually be a relocation on the offset field. If there
+ are relocations on the size or flags, then we can't optimize
+ this entry. Also, find the next relocation to examine on the
+ next iteration. */
+ if (offset_rel)
{
- if (ELF32_R_TYPE (internal_relocs[nexti].r_info)
- != R_XTENSA_NONE)
+ if (offset_rel->r_offset >= offset + entry_size)
{
- next_irel = &internal_relocs[nexti];
- break;
+ next_rel = offset_rel;
+ /* There are no relocations on the current entry, but we
+ might still be able to remove it if the size is zero. */
+ offset_rel = NULL;
+ }
+ else if (offset_rel->r_offset > offset
+ || (extra_rel
+ && extra_rel->r_offset < offset + entry_size))
+ {
+ /* There is a relocation on the size or flags, so we can't
+ do anything with this entry. Continue with the next. */
+ next_rel = offset_rel;
+ continue;
+ }
+ else
+ {
+ BFD_ASSERT (offset_rel->r_offset == offset);
+ offset_rel->r_offset -= removed_bytes;
+ next_rel = offset_rel + 1;
}
- internal_relocs[nexti].r_offset -= removed_bytes;
}
+ else
+ next_rel = NULL;
- remove_this_irel = FALSE;
+ remove_this_rel = FALSE;
bytes_to_remove = 0;
actual_offset = offset - removed_bytes;
size = bfd_get_32 (abfd, &contents[actual_offset + 4]);
@@ -9054,90 +9098,64 @@ relax_property_section (bfd *abfd,
else
flags = predef_flags;
- /* Check that the irels are sorted by offset,
- with only one per address. */
- BFD_ASSERT (!irel || (int) irel->r_offset > (int) last_irel_offset);
- BFD_ASSERT (!next_irel || next_irel->r_offset > irel->r_offset);
-
- /* Make sure there aren't relocs on the size or flag fields. */
- if ((irel && irel->r_offset == offset + 4)
- || (is_full_prop_section
- && irel && irel->r_offset == offset + 8))
- {
- irel->r_offset -= removed_bytes;
- last_irel_offset = irel->r_offset;
- }
- else if (next_irel && (next_irel->r_offset == offset + 4
- || (is_full_prop_section
- && next_irel->r_offset == offset + 8)))
- {
- nexti += 1;
- irel->r_offset -= removed_bytes;
- next_irel->r_offset -= removed_bytes;
- last_irel_offset = next_irel->r_offset;
- }
- else if (size == 0 && (flags & XTENSA_PROP_ALIGN) == 0
- && (flags & XTENSA_PROP_UNREACHABLE) == 0)
+ if (size == 0
+ && (flags & XTENSA_PROP_ALIGN) == 0
+ && (flags & XTENSA_PROP_UNREACHABLE) == 0)
{
/* Always remove entries with zero size and no alignment. */
bytes_to_remove = entry_size;
- if (irel && irel->r_offset == offset)
- {
- remove_this_irel = TRUE;
-
- irel->r_offset -= removed_bytes;
- last_irel_offset = irel->r_offset;
- }
+ if (offset_rel)
+ remove_this_rel = TRUE;
}
- else if (irel && irel->r_offset == offset)
+ else if (offset_rel
+ && ELF32_R_TYPE (offset_rel->r_info) == R_XTENSA_32)
{
- if (ELF32_R_TYPE (irel->r_info) == R_XTENSA_32)
+ if (last_irel)
{
- if (last_irel)
- {
- flagword old_flags;
- bfd_vma old_size =
- bfd_get_32 (abfd, &contents[last_irel->r_offset + 4]);
- bfd_vma old_address =
- (last_irel->r_addend
- + bfd_get_32 (abfd, &contents[last_irel->r_offset]));
- bfd_vma new_address =
- (irel->r_addend
- + bfd_get_32 (abfd, &contents[actual_offset]));
- if (is_full_prop_section)
- old_flags = bfd_get_32
- (abfd, &contents[last_irel->r_offset + 8]);
- else
- old_flags = predef_flags;
+ flagword old_flags;
+ bfd_vma old_size =
+ bfd_get_32 (abfd, &contents[last_irel->r_offset + 4]);
+ bfd_vma old_address =
+ (last_irel->r_addend
+ + bfd_get_32 (abfd, &contents[last_irel->r_offset]));
+ bfd_vma new_address =
+ (offset_rel->r_addend
+ + bfd_get_32 (abfd, &contents[actual_offset]));
+ if (is_full_prop_section)
+ old_flags = bfd_get_32
+ (abfd, &contents[last_irel->r_offset + 8]);
+ else
+ old_flags = predef_flags;
- if ((ELF32_R_SYM (irel->r_info)
- == ELF32_R_SYM (last_irel->r_info))
- && old_address + old_size == new_address
- && old_flags == flags
- && (old_flags & XTENSA_PROP_INSN_BRANCH_TARGET) == 0
- && (old_flags & XTENSA_PROP_INSN_LOOP_TARGET) == 0)
- {
- /* Fix the old size. */
- bfd_put_32 (abfd, old_size + size,
- &contents[last_irel->r_offset + 4]);
- bytes_to_remove = entry_size;
- remove_this_irel = TRUE;
- }
- else
- last_irel = irel;
+ if ((ELF32_R_SYM (offset_rel->r_info)
+ == ELF32_R_SYM (last_irel->r_info))
+ && old_address + old_size == new_address
+ && old_flags == flags
+ && (old_flags & XTENSA_PROP_INSN_BRANCH_TARGET) == 0
+ && (old_flags & XTENSA_PROP_INSN_LOOP_TARGET) == 0)
+ {
+ /* Fix the old size. */
+ bfd_put_32 (abfd, old_size + size,
+ &contents[last_irel->r_offset + 4]);
+ bytes_to_remove = entry_size;
+ remove_this_rel = TRUE;
}
else
- last_irel = irel;
+ last_irel = offset_rel;
}
-
- irel->r_offset -= removed_bytes;
- last_irel_offset = irel->r_offset;
+ else
+ last_irel = offset_rel;
}
- if (remove_this_irel)
+ if (remove_this_rel)
{
- irel->r_info = ELF32_R_INFO (0, R_XTENSA_NONE);
- irel->r_offset -= bytes_to_remove;
+ offset_rel->r_info = ELF32_R_INFO (0, R_XTENSA_NONE);
+ /* In case this is the last entry, move the relocation offset
+ to the previous entry, if there is one. */
+ if (offset_rel->r_offset >= bytes_to_remove)
+ offset_rel->r_offset -= bytes_to_remove;
+ else
+ offset_rel->r_offset = 0;
}
if (bytes_to_remove != 0)
@@ -9152,6 +9170,10 @@ relax_property_section (bfd *abfd,
if (removed_bytes)
{
+ /* Fix up any extra relocations on the last entry. */
+ for (irel = next_rel; irel < rel_end; irel++)
+ irel->r_offset -= removed_bytes;
+
/* Clear the removed bytes. */
memset (&contents[section_size - removed_bytes], 0, removed_bytes);
@@ -9526,20 +9548,23 @@ pcrel_reloc_fits (xtensa_opcode opc,
}
-static int linkonce_len = sizeof (".gnu.linkonce.") - 1;
-
static bfd_boolean
xtensa_is_property_section (asection *sec)
{
- if (CONST_STRNEQ (sec->name, XTENSA_INSN_SEC_NAME)
- || CONST_STRNEQ (sec->name, XTENSA_LIT_SEC_NAME)
- || CONST_STRNEQ (sec->name, XTENSA_PROP_SEC_NAME))
+ if (xtensa_is_insntable_section (sec)
+ || xtensa_is_littable_section (sec)
+ || xtensa_is_proptable_section (sec))
return TRUE;
- if (strncmp (".gnu.linkonce.", sec->name, linkonce_len) == 0
- && (CONST_STRNEQ (&sec->name[linkonce_len], "x.")
- || CONST_STRNEQ (&sec->name[linkonce_len], "p.")
- || CONST_STRNEQ (&sec->name[linkonce_len], "prop.")))
+ return FALSE;
+}
+
+
+static bfd_boolean
+xtensa_is_insntable_section (asection *sec)
+{
+ if (CONST_STRNEQ (sec->name, XTENSA_INSN_SEC_NAME)
+ || CONST_STRNEQ (sec->name, ".gnu.linkonce.x."))
return TRUE;
return FALSE;
@@ -9549,12 +9574,19 @@ xtensa_is_property_section (asection *se
static bfd_boolean
xtensa_is_littable_section (asection *sec)
{
- if (CONST_STRNEQ (sec->name, XTENSA_LIT_SEC_NAME))
+ if (CONST_STRNEQ (sec->name, XTENSA_LIT_SEC_NAME)
+ || CONST_STRNEQ (sec->name, ".gnu.linkonce.p."))
return TRUE;
- if (strncmp (".gnu.linkonce.", sec->name, linkonce_len) == 0
- && sec->name[linkonce_len] == 'p'
- && sec->name[linkonce_len + 1] == '.')
+ return FALSE;
+}
+
+
+static bfd_boolean
+xtensa_is_proptable_section (asection *sec)
+{
+ if (CONST_STRNEQ (sec->name, XTENSA_PROP_SEC_NAME)
+ || CONST_STRNEQ (sec->name, ".gnu.linkonce.prop."))
return TRUE;
return FALSE;
@@ -9611,6 +9643,8 @@ match_section_group (bfd *abfd ATTRIBUTE
}
+static int linkonce_len = sizeof (".gnu.linkonce.") - 1;
+
asection *
xtensa_get_property_section (asection *sec, const char *base_name)
{
@@ -9685,8 +9719,7 @@ xtensa_get_property_section (asection *s
flagword
xtensa_get_property_predef_flags (asection *sec)
{
- if (CONST_STRNEQ (sec->name, XTENSA_INSN_SEC_NAME)
- || CONST_STRNEQ (sec->name, ".gnu.linkonce.x."))
+ if (xtensa_is_insntable_section (sec))
return (XTENSA_PROP_INSN
| XTENSA_PROP_INSN_NO_TRANSFORM
| XTENSA_PROP_INSN_NO_REORDER);
next reply other threads:[~2007-04-12 19:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-12 19:13 Bob Wilson [this message]
2007-04-27 19:46 ` Bob Wilson
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