mirror/binutils-gdb
2
0
Fork 0
mirror of https://sourceware.org/git/binutils-gdb.git synced 2024-11-27 03:51:15 +08:00
Code Issues Packages Projects Releases Wiki Activity

Support multiple .eh_frame sections

Browse Source 
This patch is based on MULTIPLE_FRAME_SECTIONS and EH_FRAME_LINKONCE,
	it allows backend to enable this feature and use '--gc-sections' simply.

	* gas/dw2gencfi.h (TARGET_MULTIPLE_EH_FRAME_SECTIONS): New.
	(MULTIPLE_FRAME_SECTIONS): Add TARGET_MULTIPLE_EH_FRAME_SECTIONS.
	* gas/dw2gencfi.c (EH_FRAME_LINKONCE): Add TARGET_MULTIPLE_EH_FRAME_SECTIONS.
	(is_now_linkonce_segment): Likewise.
	(get_cfi_seg): Create relocation info between .eh_frame.* and .text.* section.

	* bfd/elf-bfd.h (elf_backend_can_make_multiple_eh_frame): New.
	* bfd/elfxx-target.h (elf_backend_can_make_multiple_eh_frame): Likewise.
	* bfd/elflink.c (_bfd_elf_default_action_discarded): Add checking for
	elf_backend_can_make_multiple_eh_frame.
This commit is contained in:
Jojo R 2022-07-14 00:28:09 +08:00
parent a494349e80
commit 853ba67882
6 changed files with 49 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
bfd/elf-bfd.h
View File

@ -1432,6 +1432,9 @@ struct elf_backend_data
bool (*elf_backend_can_make_lsda_relative_eh_frame)
(bfd *, struct bfd_link_info *, asection *);
/* Tell linker to support multiple eh_frame sections. */
bool elf_backend_can_make_multiple_eh_frame;
/* This function returns an encoding after computing the encoded
value (and storing it in ENCODED) for the given OFFSET into OSEC,
to be stored in at LOC_OFFSET into the LOC_SEC input section.

7
bfd/elflink.c
View File

@ -10924,12 +10924,19 @@ elf_section_ignore_discarded_relocs (asection *sec)
unsigned int
_bfd_elf_default_action_discarded (asection *sec)
{
const struct elf_backend_data *bed;
bed = get_elf_backend_data (sec->owner);
if (sec->flags & SEC_DEBUGGING)
return PRETEND;
if (strcmp (".eh_frame", sec->name) == 0)
return 0;
if (bed->elf_backend_can_make_multiple_eh_frame
&& strncmp (sec->name, ".eh_frame.", 10) == 0)
return 0;
if (strcmp (".gcc_except_table", sec->name) == 0)
return 0;

4
bfd/elfxx-target.h
View File

@ -658,6 +658,9 @@
#ifndef elf_backend_can_make_lsda_relative_eh_frame
#define elf_backend_can_make_lsda_relative_eh_frame _bfd_elf_can_make_relative
#endif
#ifndef elf_backend_can_make_multiple_eh_frame
#define elf_backend_can_make_multiple_eh_frame 0
#endif
#ifndef elf_backend_encode_eh_address
#define elf_backend_encode_eh_address _bfd_elf_encode_eh_address
#endif
@ -891,6 +894,7 @@ static const struct elf_backend_data elfNN_bed =
elf_backend_eh_frame_address_size,
elf_backend_can_make_relative_eh_frame,
elf_backend_can_make_lsda_relative_eh_frame,
elf_backend_can_make_multiple_eh_frame,
elf_backend_encode_eh_address,
elf_backend_write_section,
elf_backend_elfsym_local_is_section,

4
gas/doc/internals.texi
View File

@ -1581,6 +1581,10 @@ If defined, GAS will check this macro before performing any optimizations on
the DWARF call frame debug information that is emitted. Targets which
implement link time relaxation may need to define this macro and set it to zero
if it is possible to change the size of a function's prologue.
@item TARGET_MULTIPLE_EH_FRAME_SECTIONS
If defined, GAS will create multiple .eh_frame.* sections according to
the name of owner's function sections.
@end table
@node Object format backend

27
gas/dw2gencfi.c
View File

@ -75,7 +75,8 @@
# define tc_cfi_endproc(fde) ((void) (fde))
#endif
#define EH_FRAME_LINKONCE (SUPPORT_FRAME_LINKONCE || compact_eh)
#define EH_FRAME_LINKONCE (SUPPORT_FRAME_LINKONCE || compact_eh \
|| TARGET_MULTIPLE_EH_FRAME_SECTIONS)
#ifndef DWARF2_FORMAT
#define DWARF2_FORMAT(SEC) dwarf2_format_32bit
@ -277,6 +278,9 @@ is_now_linkonce_segment (void)
if (compact_eh)
return now_seg;
if (TARGET_MULTIPLE_EH_FRAME_SECTIONS)
return now_seg;
if ((bfd_section_flags (now_seg)
& (SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD
| SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE
@ -1333,14 +1337,33 @@ static segT
get_cfi_seg (segT cseg, const char *base, flagword flags, int align)
{
/* Exclude .debug_frame sections for Compact EH. */
if (SUPPORT_FRAME_LINKONCE || ((flags & SEC_DEBUGGING) == 0 && compact_eh))
if (SUPPORT_FRAME_LINKONCE || ((flags & SEC_DEBUGGING) == 0 && compact_eh)
|| ((flags & SEC_DEBUGGING) == 0 && TARGET_MULTIPLE_EH_FRAME_SECTIONS))
{
segT iseg = cseg;
struct dwcfi_seg_list *l;
l = dwcfi_hash_find_or_make (cseg, base, flags);
cseg = l->seg;
subseg_set (cseg, l->subseg);
if (TARGET_MULTIPLE_EH_FRAME_SECTIONS
&& (flags & DWARF2_EH_FRAME_READ_ONLY))
{
const frchainS *ifrch = seg_info (iseg)->frchainP;
const frchainS *frch = seg_info (cseg)->frchainP;
expressionS exp;
exp.X_op = O_symbol;
exp.X_add_symbol = (symbolS *) local_symbol_make (cseg->name, cseg, frch->frch_root, 0);
exp.X_add_number = 0;
subseg_set (iseg, ifrch->frch_subseg);
fix_new_exp (ifrch->frch_root, 0, 0, &exp, 0, BFD_RELOC_NONE);
/* Restore the original segment info. */
subseg_set (cseg, l->subseg);
}
}
else
{

7
gas/dw2gencfi.h
View File

@ -66,7 +66,12 @@ extern void cfi_add_CFA_restore_state (void);
#define SUPPORT_COMPACT_EH 0
#endif
#define MULTIPLE_FRAME_SECTIONS (SUPPORT_FRAME_LINKONCE || SUPPORT_COMPACT_EH)
#ifndef TARGET_MULTIPLE_EH_FRAME_SECTIONS
#define TARGET_MULTIPLE_EH_FRAME_SECTIONS 0
#endif
#define MULTIPLE_FRAME_SECTIONS (SUPPORT_FRAME_LINKONCE || SUPPORT_COMPACT_EH \
|| TARGET_MULTIPLE_EH_FRAME_SECTIONS)
struct cfi_insn_data
{