/* .eh_frame section optimization.
- Copyright 2001 Free Software Foundation, Inc.
+ Copyright 2001, 2002 Free Software Foundation, Inc.
Written by Jakub Jelinek <jakub@redhat.com>.
This file is part of BFD, the Binary File Descriptor library.
#define EH_FRAME_HDR_SIZE 8
-struct cie_header
-{
- unsigned int length;
- unsigned int id;
-};
-
-struct cie
-{
- struct cie_header hdr;
- unsigned char version;
- unsigned char augmentation[20];
- unsigned int code_align;
- int data_align;
- unsigned int ra_column;
- unsigned int augmentation_size;
- struct elf_link_hash_entry *personality;
- unsigned char per_encoding;
- unsigned char lsda_encoding;
- unsigned char fde_encoding;
- unsigned char initial_insn_length;
- unsigned char make_relative;
- unsigned char make_lsda_relative;
- unsigned char initial_instructions[50];
-};
-
-struct eh_cie_fde
-{
- unsigned int offset;
- unsigned int size;
- asection *sec;
- unsigned int new_offset;
- unsigned char fde_encoding;
- unsigned char lsda_encoding;
- unsigned char lsda_offset;
- unsigned char cie : 1;
- unsigned char removed : 1;
- unsigned char make_relative : 1;
- unsigned char make_lsda_relative : 1;
-};
-
-struct eh_frame_sec_info
-{
- unsigned int count;
- unsigned int alloced;
- struct eh_cie_fde entry[1];
-};
-
-struct eh_frame_array_ent
-{
- bfd_vma initial_loc;
- bfd_vma fde;
-};
-
-struct eh_frame_hdr_info
-{
- struct cie last_cie;
- asection *last_cie_sec;
- unsigned int last_cie_offset;
- unsigned int fde_count, array_count;
- struct eh_frame_array_ent *array;
- /* TRUE if .eh_frame_hdr should contain the sorted search table.
- We build it if we successfully read all .eh_frame input sections
- and recognize them. */
- boolean table;
- boolean strip;
-};
-
static bfd_vma read_unsigned_leb128
PARAMS ((bfd *, char *, unsigned int *));
static bfd_signed_vma read_signed_leb128
return value;
}
-
+
/* Store a width sized value to memory. */
static void
/* This function is called for each input file before the .eh_frame
section is relocated. It discards duplicate CIEs and FDEs for discarded
- functions. The function returns true iff any entries have been
+ functions. The function returns TRUE iff any entries have been
deleted. */
-boolean
-_bfd_elf_discard_section_eh_frame (abfd, info, sec, ehdrsec,
+bfd_boolean
+_bfd_elf_discard_section_eh_frame (abfd, info, sec,
reloc_symbol_deleted_p, cookie)
bfd *abfd;
struct bfd_link_info *info;
- asection *sec, *ehdrsec;
- boolean (*reloc_symbol_deleted_p) (bfd_vma, PTR);
+ asection *sec;
+ bfd_boolean (*reloc_symbol_deleted_p) PARAMS ((bfd_vma, PTR));
struct elf_reloc_cookie *cookie;
{
bfd_byte *ehbuf = NULL, *buf;
bfd_byte *last_cie, *last_fde;
struct cie_header hdr;
struct cie cie;
+ struct elf_link_hash_table *htab;
struct eh_frame_hdr_info *hdr_info;
struct eh_frame_sec_info *sec_info = NULL;
unsigned int leb128_tmp;
unsigned int cie_usage_count, last_cie_ndx, i, offset;
unsigned int make_relative, make_lsda_relative;
- Elf_Internal_Rela *rel;
bfd_size_type new_size;
unsigned int ptr_size;
if (sec->_raw_size == 0)
{
/* This file does not contain .eh_frame information. */
- return false;
+ return FALSE;
}
if ((sec->output_section != NULL
{
/* At least one of the sections is being discarded from the
link, so we should just ignore them. */
- return false;
+ return FALSE;
}
- BFD_ASSERT (elf_section_data (ehdrsec)->sec_info_type
- == ELF_INFO_TYPE_EH_FRAME_HDR);
- hdr_info = (struct eh_frame_hdr_info *)
- elf_section_data (ehdrsec)->sec_info;
+ htab = elf_hash_table (info);
+ hdr_info = &htab->eh_info;
/* Read the frame unwind information from abfd. */
{
/* Empty .eh_frame section. */
free (ehbuf);
- return false;
+ return FALSE;
}
/* If .eh_frame section size doesn't fit into int, we cannot handle
#define ENSURE_NO_RELOCS(buf) \
if (cookie->rel < cookie->relend \
&& (cookie->rel->r_offset \
- < (bfd_size_type) ((buf) - ehbuf))) \
+ < (bfd_size_type) ((buf) - ehbuf)) \
+ && cookie->rel->r_info != 0) \
goto free_no_table
#define SKIP_RELOCS(buf) \
/* 64-bit .eh_frame is not supported. */
goto free_no_table;
buf += 4;
- if ((buf - ehbuf) + hdr.length > sec->_raw_size)
+ if ((bfd_size_type) (buf - ehbuf) + hdr.length > sec->_raw_size)
/* CIE/FDE not contained fully in this .eh_frame input section. */
goto free_no_table;
/* CIE */
if (last_cie != NULL)
{
- /* Now check if this CIE is identical to last CIE, in which case
- we can remove it, provided we adjust all FDEs.
- Also, it can be removed if we have removed all FDEs using
- that. */
- if (cie_compare (&cie, &hdr_info->last_cie) == 0
+ /* Now check if this CIE is identical to the last CIE,
+ in which case we can remove it provided we adjust
+ all FDEs. Also, it can be removed if we have removed
+ all FDEs using it. */
+ if ((!info->relocateable
+ && cie_compare (&cie, &hdr_info->last_cie) == 0)
|| cie_usage_count == 0)
{
new_size -= cie.hdr.length + 4;
= cie.make_relative;
sec_info->entry[last_cie_ndx].make_lsda_relative
= cie.make_lsda_relative;
+ sec_info->entry[last_cie_ndx].per_encoding_relative
+ = (cie.per_encoding & 0x70) == DW_EH_PE_pcrel;
}
}
}
read_uleb128 (cie.code_align, buf);
read_sleb128 (cie.data_align, buf);
+ /* Note - in DWARF2 the return address column is an unsigned byte.
+ In DWARF3 it is a ULEB128. We are following DWARF3. For most
+ ports this will not matter as the value will be less than 128.
+ For the others (eg FRV, SH, MMIX, IA64) they need a fixed GCC
+ which conforms to the DWARF3 standard. */
read_uleb128 (cie.ra_column, buf);
ENSURE_NO_RELOCS (buf);
cie.lsda_encoding = DW_EH_PE_omit;
+ ((buf - ehbuf + per_width - 1)
& ~((bfd_size_type) per_width - 1)));
ENSURE_NO_RELOCS (buf);
- rel = GET_RELOC (buf);
/* Ensure we have a reloc here, against
a global symbol. */
- if (rel != NULL)
+ if (GET_RELOC (buf) != NULL)
{
unsigned long r_symndx;
}
/* For shared libraries, try to get rid of as many RELATIVE relocs
- as possible.
- FIXME: For this to work, ELF backends need to perform the
- relocation if omitting dynamic relocs, not skip it. */
- if (0
- && info->shared
+ as possible. */
+ if (info->shared
&& (cie.fde_encoding & 0xf0) == DW_EH_PE_absptr)
cie.make_relative = 1;
- if (0
- && info->shared
+ if (info->shared
&& (cie.lsda_encoding & 0xf0) == DW_EH_PE_absptr)
cie.make_lsda_relative = 1;
goto free_no_table;
ENSURE_NO_RELOCS (buf);
- rel = GET_RELOC (buf);
- if (rel == NULL)
+ if (GET_RELOC (buf) == NULL)
/* This should not happen. */
goto free_no_table;
if ((*reloc_symbol_deleted_p) (buf - ehbuf, cookie))
{
- cookie->rel = rel;
- /* This is a FDE against discarded section, it should
+ /* This is a FDE against a discarded section. It should
be deleted. */
new_size -= hdr.length + 4;
sec_info->entry[sec_info->count].removed = 1;
}
else
{
+ if (info->shared
+ && (((cie.fde_encoding & 0xf0) == DW_EH_PE_absptr
+ && cie.make_relative == 0)
+ || (cie.fde_encoding & 0xf0) == DW_EH_PE_aligned))
+ {
+ /* If a shared library uses absolute pointers
+ which we cannot turn into PC relative,
+ don't create the binary search table,
+ since it is affected by runtime relocations. */
+ hdr_info->table = FALSE;
+ }
cie_usage_count++;
hdr_info->fde_count++;
}
- cookie->rel = rel;
if (cie.lsda_encoding != DW_EH_PE_omit)
{
unsigned int dummy;
{
sec_info->entry[i].make_relative = make_relative;
sec_info->entry[i].make_lsda_relative = make_lsda_relative;
+ sec_info->entry[i].per_encoding_relative = 0;
}
}
else if (sec_info->entry[i].cie && sec_info->entry[i].sec == sec)
free (ehbuf);
if (sec_info)
free (sec_info);
- hdr_info->table = false;
+ hdr_info->table = FALSE;
hdr_info->last_cie.hdr.length = 0;
- return false;
+ return FALSE;
}
/* This function is called for .eh_frame_hdr section after
_bfd_elf_discard_section_eh_frame has been called on all .eh_frame
input sections. It finalizes the size of .eh_frame_hdr section. */
-boolean
-_bfd_elf_discard_section_eh_frame_hdr (abfd, info, sec)
+bfd_boolean
+_bfd_elf_discard_section_eh_frame_hdr (abfd, info)
bfd *abfd;
struct bfd_link_info *info;
- asection *sec;
{
+ struct elf_link_hash_table *htab;
struct eh_frame_hdr_info *hdr_info;
- unsigned int ptr_size;
-
- ptr_size = (elf_elfheader (abfd)->e_ident[EI_CLASS]
- == ELFCLASS64) ? 8 : 4;
+ asection *sec;
- if ((elf_section_data (sec)->sec_info_type
- != ELF_INFO_TYPE_EH_FRAME_HDR)
- || ! info->eh_frame_hdr)
- {
- _bfd_strip_section_from_output (info, sec);
- return false;
- }
+ htab = elf_hash_table (info);
+ hdr_info = &htab->eh_info;
+ sec = hdr_info->hdr_sec;
+ if (sec == NULL)
+ return FALSE;
- hdr_info = (struct eh_frame_hdr_info *)
- elf_section_data (sec)->sec_info;
- if (hdr_info->strip)
- return false;
sec->_cooked_size = EH_FRAME_HDR_SIZE;
if (hdr_info->table)
sec->_cooked_size += 4 + hdr_info->fde_count * 8;
/* Request program headers to be recalculated. */
elf_tdata (abfd)->program_header_size = 0;
- elf_tdata (abfd)->eh_frame_hdr = true;
- return true;
+ elf_tdata (abfd)->eh_frame_hdr = sec;
+ return TRUE;
}
/* This function is called from size_dynamic_sections.
because later on it is too late for calling _bfd_strip_section_from_output,
since dynamic symbol table has been sized. */
-boolean
+bfd_boolean
_bfd_elf_maybe_strip_eh_frame_hdr (info)
struct bfd_link_info *info;
{
- asection *sec, *o;
+ asection *o;
bfd *abfd;
+ struct elf_link_hash_table *htab;
struct eh_frame_hdr_info *hdr_info;
- sec = bfd_get_section_by_name (elf_hash_table (info)->dynobj, ".eh_frame_hdr");
- if (sec == NULL)
- return true;
-
- hdr_info
- = bfd_zmalloc (sizeof (struct eh_frame_hdr_info));
- if (hdr_info == NULL)
- return false;
+ htab = elf_hash_table (info);
+ hdr_info = &htab->eh_info;
+ if (hdr_info->hdr_sec == NULL)
+ return TRUE;
- elf_section_data (sec)->sec_info = hdr_info;
- elf_section_data (sec)->sec_info_type = ELF_INFO_TYPE_EH_FRAME_HDR;
+ if (bfd_is_abs_section (hdr_info->hdr_sec->output_section))
+ {
+ hdr_info->hdr_sec = NULL;
+ return TRUE;
+ }
abfd = NULL;
if (info->eh_frame_hdr)
/* Count only sections which have at least a single CIE or FDE.
There cannot be any CIE or FDE <= 8 bytes. */
o = bfd_get_section_by_name (abfd, ".eh_frame");
- if (o && o->_raw_size > 8)
+ if (o && o->_raw_size > 8 && !bfd_is_abs_section (o->output_section))
break;
}
if (abfd == NULL)
{
- _bfd_strip_section_from_output (info, sec);
- hdr_info->strip = true;
+ _bfd_strip_section_from_output (info, hdr_info->hdr_sec);
+ hdr_info->hdr_sec = NULL;
+ return TRUE;
}
- else
- hdr_info->table = true;
- return true;
+
+ hdr_info->table = TRUE;
+ return TRUE;
}
/* Adjust an address in the .eh_frame section. Given OFFSET within
if (sec_info->entry[mid].make_relative
&& ! sec_info->entry[mid].cie
&& offset == sec_info->entry[mid].offset + 8)
- return (bfd_vma) -1;
+ return (bfd_vma) -2;
/* If converting LSDA pointers to DW_EH_PE_pcrel, there will be no need
for run-time relocation against LSDA field. */
if (sec_info->entry[mid].make_lsda_relative
&& ! sec_info->entry[mid].cie
- && (offset
- == (sec_info->entry[mid].offset + 8
- + sec_info->entry[mid].lsda_offset)))
- return (bfd_vma) -1;
+ && (offset == (sec_info->entry[mid].offset + 8
+ + sec_info->entry[mid].lsda_offset)))
+ return (bfd_vma) -2;
- return (offset
- + (sec_info->entry[mid].new_offset - sec_info->entry[mid].offset));
+ return (offset + sec_info->entry[mid].new_offset
+ - sec_info->entry[mid].offset);
}
/* Write out .eh_frame section. This is called with the relocated
contents. */
-boolean
-_bfd_elf_write_section_eh_frame (abfd, sec, ehdrsec, contents)
+bfd_boolean
+_bfd_elf_write_section_eh_frame (abfd, info, sec, contents)
bfd *abfd;
- asection *sec, *ehdrsec;
+ struct bfd_link_info *info;
+ asection *sec;
bfd_byte *contents;
{
struct eh_frame_sec_info *sec_info;
+ struct elf_link_hash_table *htab;
struct eh_frame_hdr_info *hdr_info;
unsigned int i;
bfd_byte *p, *buf;
sec->_raw_size);
sec_info = (struct eh_frame_sec_info *)
elf_section_data (sec)->sec_info;
- hdr_info = NULL;
- if (ehdrsec
- && (elf_section_data (ehdrsec)->sec_info_type
- == ELF_INFO_TYPE_EH_FRAME_HDR))
- {
- hdr_info = (struct eh_frame_hdr_info *)
- elf_section_data (ehdrsec)->sec_info;
- if (hdr_info->table && hdr_info->array == NULL)
- hdr_info->array
- = bfd_malloc (hdr_info->fde_count * sizeof(*hdr_info->array));
- if (hdr_info->array == NULL)
- hdr_info = NULL;
- }
+ htab = elf_hash_table (info);
+ hdr_info = &htab->eh_info;
+ if (hdr_info->table && hdr_info->array == NULL)
+ hdr_info->array
+ = bfd_malloc (hdr_info->fde_count * sizeof(*hdr_info->array));
+ if (hdr_info->array == NULL)
+ hdr_info = NULL;
p = contents;
for (i = 0; i < sec_info->count; ++i)
{
if (sec_info->entry[i].cie)
{
- cie_offset = sec_info->entry[i].new_offset;
- cie_offset += (sec_info->entry[i].sec->output_section->vma
- + sec_info->entry[i].sec->output_offset
- - sec->output_section->vma
- - sec->output_offset);
+ /* If CIE is removed due to no remaining FDEs referencing it
+ and there were no CIEs kept before it, sec_info->entry[i].sec
+ will be zero. */
+ if (sec_info->entry[i].sec == NULL)
+ cie_offset = 0;
+ else
+ {
+ cie_offset = sec_info->entry[i].new_offset;
+ cie_offset += (sec_info->entry[i].sec->output_section->vma
+ + sec_info->entry[i].sec->output_offset
+ - sec->output_section->vma
+ - sec->output_offset);
+ }
}
continue;
}
+
if (sec_info->entry[i].cie)
{
/* CIE */
cie_offset = sec_info->entry[i].new_offset;
if (sec_info->entry[i].make_relative
- || sec_info->entry[i].make_lsda_relative)
+ || sec_info->entry[i].make_lsda_relative
+ || sec_info->entry[i].per_encoding_relative)
{
unsigned char *aug;
unsigned int action;
/* Need to find 'R' or 'L' augmentation's argument and modify
DW_EH_PE_* value. */
action = (sec_info->entry[i].make_relative ? 1 : 0)
- | (sec_info->entry[i].make_lsda_relative ? 2 : 0);
+ | (sec_info->entry[i].make_lsda_relative ? 2 : 0)
+ | (sec_info->entry[i].per_encoding_relative ? 4 : 0);
buf = contents + sec_info->entry[i].offset;
/* Skip length, id and version. */
buf += 9;
per_width = get_DW_EH_PE_width (per_encoding,
ptr_size);
BFD_ASSERT (per_width != 0);
+ BFD_ASSERT (((per_encoding & 0x70) == DW_EH_PE_pcrel)
+ == sec_info->entry[i].per_encoding_relative);
if ((per_encoding & 0xf0) == DW_EH_PE_aligned)
buf = (contents
+ ((buf - contents + per_width - 1)
& ~((bfd_size_type) per_width - 1)));
+ if (action & 4)
+ {
+ bfd_vma value;
+
+ value = read_value (abfd, buf, per_width);
+ value += (sec_info->entry[i].offset
+ - sec_info->entry[i].new_offset);
+ write_value (abfd, buf, value, per_width);
+ action &= ~4;
+ }
buf += per_width;
break;
case 'R':
}
}
}
- else
+ else if (sec_info->entry[i].size > 4)
{
/* FDE */
bfd_vma value = 0, address;
unsigned int width;
buf = contents + sec_info->entry[i].offset;
- /* Skip length. */
+ /* Skip length. */
buf += 4;
bfd_put_32 (abfd,
sec_info->entry[i].new_offset + 4 - cie_offset, buf);
}
}
}
+ else
+ /* Terminating FDE must be at the end of .eh_frame section only. */
+ BFD_ASSERT (i == sec_info->count - 1);
BFD_ASSERT (p == contents + sec_info->entry[i].new_offset);
memmove (p, contents + sec_info->entry[i].offset,
FDE initial_location field and FDE address,
sorted by increasing initial_loc) */
-boolean
-_bfd_elf_write_section_eh_frame_hdr (abfd, sec)
+bfd_boolean
+_bfd_elf_write_section_eh_frame_hdr (abfd, info)
bfd *abfd;
- asection *sec;
+ struct bfd_link_info *info;
{
+ struct elf_link_hash_table *htab;
struct eh_frame_hdr_info *hdr_info;
- unsigned int ptr_size;
+ asection *sec;
bfd_byte *contents;
asection *eh_frame_sec;
bfd_size_type size;
- ptr_size = (elf_elfheader (sec->owner)->e_ident[EI_CLASS]
- == ELFCLASS64) ? 8 : 4;
+ htab = elf_hash_table (info);
+ hdr_info = &htab->eh_info;
+ sec = hdr_info->hdr_sec;
+ if (sec == NULL)
+ return TRUE;
- BFD_ASSERT (elf_section_data (sec)->sec_info_type
- == ELF_INFO_TYPE_EH_FRAME_HDR);
- hdr_info = (struct eh_frame_hdr_info *)
- elf_section_data (sec)->sec_info;
size = EH_FRAME_HDR_SIZE;
if (hdr_info->array && hdr_info->array_count == hdr_info->fde_count)
size += 4 + hdr_info->fde_count * 8;
contents = bfd_malloc (size);
if (contents == NULL)
- return false;
+ return FALSE;
eh_frame_sec = bfd_get_section_by_name (abfd, ".eh_frame");
if (eh_frame_sec == NULL)
- return false;
+ return FALSE;
memset (contents, 0, EH_FRAME_HDR_SIZE);
contents[0] = 1; /* Version */
projects / deliverable / binutils-gdb.git / blobdiff