* [PATCH v3] Support SHF_GNU_RETAIN ELF Section Flag
@ 2020-10-09 10:59 Jozef Lawrynowicz
2020-10-19 19:47 ` Jozef Lawrynowicz
0 siblings, 1 reply; 2+ messages in thread
From: Jozef Lawrynowicz @ 2020-10-09 10:59 UTC (permalink / raw)
To: binutils
[-- Attachment #1: Type: text/plain, Size: 1883 bytes --]
The attached patch is version 3 of the SHF_GNU_RETAIN patch that was
previously discussed here:
Version 1:
https://sourceware.org/pipermail/binutils/2020-September/113406.html
Version 2:
https://sourceware.org/pipermail/binutils/2020-October/113559.html
The following changes have been made since version 2:
- Removed "if it is unused" phrase from SHF_GNU_RETAIN definition.
The definition now reads:
"The link editor should not garbage collect the section."
- Aligned OSABI error messages in bfd/elf.c with those in
gas/config/obj-elf.c.
- Added OSABI checks before SHF_GNU_RETAIN is used in bfd/elflink.c.
- Added OSABI checks and new tests before SHF_GNU_RETAIN and
SHF_GNU_MBIND are used in binutils/readelf.c.
- Removed support in GAS for unique sections to be created with the same
name, but different states for SHF_GNU_RETAIN. This exception is not
required for SHF_GNU_RETAIN support.
- Added warning/error message when SHF_GNU_RETAIN state is not
consistent when changing sections. Added tests for this.
- Added support for flags in the SHF_MASKOS range to be set with numeric
values to the flags argument of the .section directive. Added tests
for this.
I've successfully regtested the patch for the Binutils, GAS and LD
testsuites for the following targets:
aarch64-elf arc-elf arm-eabi arm-elf avr-elf bfin-elf cr16-elf cris-elf
crx-elf csky-elf d10v-elf d30v-elf dlx-elf epiphany-elf fr30-elf frv-elf
ft32-elf h8300-elf hppa-elf i386-elf ip2k-elf iq2000-elf lm32-elf
m32c-elf m32r-elf m68hc11-elf m68hc12-elf m68k-elf mcore-elf mep-elf
metag-elf microblaze-elf mips-elf moxie-elf msp430-elf mt-elf nios2-elf
or1k-elf pj-elf ppc-elf pru-elf riscv-elf rl78-elf rx-elf s12z-elf
score-elf sh-elf sparc-elf spu-elf tic6x-elf tilegx-elf tilepro-elf
v850-elf visium-elf wasm32-elf xgate-elf xstormy16-elf xtensa-elf
z80-elf.
Ok to apply?
Thanks,
Jozef
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From 9709145da0644b6657a892ad8e513ace81359c7d Mon Sep 17 00:00:00 2001
From: Jozef Lawrynowicz <jozef.l@mittosystems.com>
Date: Fri, 9 Oct 2020 11:52:55 +0100
Subject: [PATCH] Support SHF_GNU_RETAIN ELF section flag
The SHF_GNU_RETAIN section flag is an extension to the GNU ELF OSABI.
It is defined as follows:
=======================================================================
Section Attribute Flags
+-------------------------------------+
| Name | Value |
+-------------------------------------+
| SHF_GNU_RETAIN | 0x200000 (1 << 21) |
+-------------------------------------+
SHF_GNU_RETAIN
The link editor should not garbage collect the section.
=======================================================================
Note that there is not a direct mapping of SHF_GNU_RETAIN to the BFD
section flag SEC_KEEP. This would prevent the user being able to
explicitly remove an SHF_GNU_RETAIN section by placing it in /DISCARD/.
bfd/ChangeLog:
2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
H.J. Lu <hongjiu.lu@intel.com>
* elf-bfd.h (enum elf_gnu_osabi): Add elf_gnu_osabi_retain.
(struct elf_obj_tdata): Increase has_gnu_osabi to 4 bits.
* elf.c (_bfd_elf_make_section_from_shdr): Set elf_gnu_osabi_retain
for SHF_GNU_RETAIN.
(_bfd_elf_final_write_processing): Report if SHF_GNU_RETAIN is
not supported by the OSABI.
Adjust error messages.
* elflink.c (bfd_elf_gc_sections): gc_mark the section if
SHF_GNU_RETAIN is set.
binutils/ChangeLog:
2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* NEWS: Announce SHF_GNU_RETAIN.
* readelf.c (get_elf_section_flags): Handle SHF_GNU_RETAIN.
Recognize SHF_GNU_RETAIN and SHF_GNU_MBIND only for supported OSABIs.
* testsuite/binutils-all/readelf.exp: Run new tests.
Don't run run_dump_test when there isn't an assembler available.
* testsuite/lib/binutils-common.exp (supports_gnu_osabi): Adjust
comment.
* testsuite/binutils-all/readelf-maskos-1a.d: New test.
* testsuite/binutils-all/readelf-maskos-1b.d: New test.
* testsuite/binutils-all/readelf-maskos.s: New test.
* testsuite/binutils-all/retain1.s: New test.
* testsuite/binutils-all/retain1a.d: New test.
* testsuite/binutils-all/retain1b.d: New test.
gas/ChangeLog:
2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
H.J. Lu <hongjiu.lu@intel.com>
* NEWS: Announce SHF_GNU_RETAIN.
* config/obj-elf.c (get_section_by_match): Update struct member name.
(obj_elf_change_section): Warn/error for state change of SHF_GNU_RETAIN.
(obj_elf_parse_section_letters): Handle 'R' flag.
Handle numeric flag values within the SHF_MASKOS range.
(obj_elf_section): Validate SHF_GNU_RETAIN usage.
* config/obj-elf.h (struct elf_section_match): Adjust "info" member
name to "sh_info". Add "sh_flags" member.
* doc/as.texi (Section): Document 'R' flag.
* testsuite/gas/elf/elf.exp: Run new tests.
* testsuite/gas/elf/section10.d: Don't test SHF_GNU_RETAIN bit of
section flag.
* testsuite/gas/elf/section10.s: Don't set SHF_GNU_RETAIN bit of
section flag.
* testsuite/gas/elf/section22.d: New test.
* testsuite/gas/elf/section22.s: New test.
* testsuite/gas/elf/section23.s: New test.
* testsuite/gas/elf/section23a.d: New test.
* testsuite/gas/elf/section23b.d: New test.
* testsuite/gas/elf/section23b.err: New test.
* testsuite/gas/elf/section24.d: New test.
* testsuite/gas/elf/section24.l: New test.
* testsuite/gas/elf/section24.s: New test.
include/ChangeLog:
2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* elf/common.h (SHF_GNU_RETAIN): Define.
ld/ChangeLog:
2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* NEWS: Announce SHF_GNU_RETAIN.
* ld.texi (garbage collection): Document SHF_GNU_RETAIN.
(Output Section Discarding): Likewise.
* testsuite/ld-elf/elf.exp: Run new tests.
* testsuite/ld-elf/retain1.s: New test.
* testsuite/ld-elf/retain1a.d: New test.
* testsuite/ld-elf/retain1b.d: New test.
* testsuite/ld-elf/retain2.d: New test.
* testsuite/ld-elf/retain2.ld: New test.
* testsuite/ld-elf/retain2.map: New test.
* testsuite/ld-elf/retain3.d: New test.
* testsuite/ld-elf/retain3.s: New test.
* testsuite/ld-elf/retain4.d: New test.
* testsuite/ld-elf/retain4.s: New test.
* testsuite/ld-elf/retain5.d: New test.
* testsuite/ld-elf/retain5.map: New test.
* testsuite/ld-elf/retain5lib.s: New test.
* testsuite/ld-elf/retain5main.s: New test.
* testsuite/ld-elf/retain6a.d: New test.
* testsuite/ld-elf/retain6b.d: New test.
* testsuite/ld-elf/retain6lib.s: New test.
* testsuite/ld-elf/retain6main.s: New test.
---
bfd/elf-bfd.h | 9 +-
bfd/elf.c | 17 ++-
bfd/elflink.c | 4 +-
binutils/NEWS | 4 +
binutils/readelf.c | 51 ++++++++-
.../binutils-all/readelf-maskos-1a.d | 10 ++
.../binutils-all/readelf-maskos-1b.d | 12 ++
.../testsuite/binutils-all/readelf-maskos.s | 11 ++
binutils/testsuite/binutils-all/readelf.exp | 9 +-
binutils/testsuite/binutils-all/retain1.s | 104 ++++++++++++++++++
binutils/testsuite/binutils-all/retain1a.d | 18 +++
binutils/testsuite/binutils-all/retain1b.d | 46 ++++++++
binutils/testsuite/lib/binutils-common.exp | 5 +-
gas/NEWS | 5 +
gas/config/obj-elf.c | 88 +++++++++++----
gas/config/obj-elf.h | 3 +-
gas/doc/as.texi | 3 +
gas/testsuite/gas/elf/elf.exp | 5 +-
gas/testsuite/gas/elf/section10.d | 4 +-
gas/testsuite/gas/elf/section10.s | 4 +-
gas/testsuite/gas/elf/section22.d | 19 ++++
gas/testsuite/gas/elf/section22.s | 34 ++++++
gas/testsuite/gas/elf/section23.s | 11 ++
gas/testsuite/gas/elf/section23a.d | 11 ++
gas/testsuite/gas/elf/section23b.d | 6 +
gas/testsuite/gas/elf/section23b.err | 2 +
gas/testsuite/gas/elf/section24.d | 18 +++
gas/testsuite/gas/elf/section24.l | 4 +
gas/testsuite/gas/elf/section24.s | 32 ++++++
include/elf/common.h | 1 +
ld/NEWS | 4 +
ld/ld.texi | 7 ++
ld/testsuite/ld-elf/elf.exp | 11 ++
ld/testsuite/ld-elf/retain1.s | 104 ++++++++++++++++++
ld/testsuite/ld-elf/retain1a.d | 28 +++++
ld/testsuite/ld-elf/retain1b.d | 11 ++
ld/testsuite/ld-elf/retain2.d | 6 +
ld/testsuite/ld-elf/retain2.ld | 7 ++
ld/testsuite/ld-elf/retain2.map | 32 ++++++
ld/testsuite/ld-elf/retain3.d | 12 ++
ld/testsuite/ld-elf/retain3.s | 19 ++++
ld/testsuite/ld-elf/retain4.d | 10 ++
ld/testsuite/ld-elf/retain4.s | 13 +++
ld/testsuite/ld-elf/retain5.d | 12 ++
ld/testsuite/ld-elf/retain5.map | 5 +
ld/testsuite/ld-elf/retain5lib.s | 6 +
ld/testsuite/ld-elf/retain5main.s | 5 +
ld/testsuite/ld-elf/retain6a.d | 14 +++
ld/testsuite/ld-elf/retain6b.d | 11 ++
ld/testsuite/ld-elf/retain6lib.s | 17 +++
ld/testsuite/ld-elf/retain6main.s | 13 +++
51 files changed, 853 insertions(+), 44 deletions(-)
create mode 100644 binutils/testsuite/binutils-all/readelf-maskos-1a.d
create mode 100644 binutils/testsuite/binutils-all/readelf-maskos-1b.d
create mode 100644 binutils/testsuite/binutils-all/readelf-maskos.s
create mode 100644 binutils/testsuite/binutils-all/retain1.s
create mode 100644 binutils/testsuite/binutils-all/retain1a.d
create mode 100644 binutils/testsuite/binutils-all/retain1b.d
create mode 100644 gas/testsuite/gas/elf/section22.d
create mode 100644 gas/testsuite/gas/elf/section22.s
create mode 100644 gas/testsuite/gas/elf/section23.s
create mode 100644 gas/testsuite/gas/elf/section23a.d
create mode 100644 gas/testsuite/gas/elf/section23b.d
create mode 100644 gas/testsuite/gas/elf/section23b.err
create mode 100644 gas/testsuite/gas/elf/section24.d
create mode 100644 gas/testsuite/gas/elf/section24.l
create mode 100644 gas/testsuite/gas/elf/section24.s
create mode 100644 ld/testsuite/ld-elf/retain1.s
create mode 100644 ld/testsuite/ld-elf/retain1a.d
create mode 100644 ld/testsuite/ld-elf/retain1b.d
create mode 100644 ld/testsuite/ld-elf/retain2.d
create mode 100644 ld/testsuite/ld-elf/retain2.ld
create mode 100644 ld/testsuite/ld-elf/retain2.map
create mode 100644 ld/testsuite/ld-elf/retain3.d
create mode 100644 ld/testsuite/ld-elf/retain3.s
create mode 100644 ld/testsuite/ld-elf/retain4.d
create mode 100644 ld/testsuite/ld-elf/retain4.s
create mode 100644 ld/testsuite/ld-elf/retain5.d
create mode 100644 ld/testsuite/ld-elf/retain5.map
create mode 100644 ld/testsuite/ld-elf/retain5lib.s
create mode 100644 ld/testsuite/ld-elf/retain5main.s
create mode 100644 ld/testsuite/ld-elf/retain6a.d
create mode 100644 ld/testsuite/ld-elf/retain6b.d
create mode 100644 ld/testsuite/ld-elf/retain6lib.s
create mode 100644 ld/testsuite/ld-elf/retain6main.s
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 140a98594d..ffb75f7919 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -1897,14 +1897,15 @@ struct output_elf_obj_tdata
bfd_boolean flags_init;
};
-/* Indicate if the bfd contains SHF_GNU_MBIND sections or symbols that
- have the STT_GNU_IFUNC symbol type or STB_GNU_UNIQUE binding. Used
- to set the osabi field in the ELF header structure. */
+/* Indicate if the bfd contains SHF_GNU_MBIND/SHF_GNU_RETAIN sections or
+ symbols that have the STT_GNU_IFUNC symbol type or STB_GNU_UNIQUE
+ binding. Used to set the osabi field in the ELF header structure. */
enum elf_gnu_osabi
{
elf_gnu_osabi_mbind = 1 << 0,
elf_gnu_osabi_ifunc = 1 << 1,
elf_gnu_osabi_unique = 1 << 2,
+ elf_gnu_osabi_retain = 1 << 3,
};
typedef struct elf_section_list
@@ -2034,7 +2035,7 @@ struct elf_obj_tdata
ENUM_BITFIELD (dynamic_lib_link_class) dyn_lib_class : 4;
/* Whether the bfd uses OS specific bits that require ELFOSABI_GNU. */
- ENUM_BITFIELD (elf_gnu_osabi) has_gnu_osabi : 3;
+ ENUM_BITFIELD (elf_gnu_osabi) has_gnu_osabi : 4;
/* Whether if the bfd contains the GNU_PROPERTY_NO_COPY_ON_PROTECTED
property. */
diff --git a/bfd/elf.c b/bfd/elf.c
index 9d7cbd52e0..dc097e825a 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -1066,9 +1066,12 @@ _bfd_elf_make_section_from_shdr (bfd *abfd,
/* FIXME: We should not recognize SHF_GNU_MBIND for ELFOSABI_NONE,
but binutils as of 2019-07-23 did not set the EI_OSABI header
byte. */
- case ELFOSABI_NONE:
case ELFOSABI_GNU:
case ELFOSABI_FREEBSD:
+ if ((hdr->sh_flags & SHF_GNU_RETAIN) != 0)
+ elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_retain;
+ /* Fall through */
+ case ELFOSABI_NONE:
if ((hdr->sh_flags & SHF_GNU_MBIND) != 0)
elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_mbind;
break;
@@ -12464,11 +12467,17 @@ _bfd_elf_final_write_processing (bfd *abfd)
&& i_ehdrp->e_ident[EI_OSABI] != ELFOSABI_FREEBSD)
{
if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_mbind)
- _bfd_error_handler (_("GNU_MBIND section is unsupported"));
+ _bfd_error_handler (_("GNU_MBIND section is supported only by GNU "
+ "and FreeBSD targets"));
if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_ifunc)
- _bfd_error_handler (_("symbol type STT_GNU_IFUNC is unsupported"));
+ _bfd_error_handler (_("symbol type STT_GNU_IFUNC is supported "
+ "only by GNU and FreeBSD targets"));
if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_unique)
- _bfd_error_handler (_("symbol binding STB_GNU_UNIQUE is unsupported"));
+ _bfd_error_handler (_("symbol binding STB_GNU_UNIQUE is supported "
+ "only by GNU and FreeBSD targets"));
+ if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_retain)
+ _bfd_error_handler (_("GNU_RETAIN section is supported "
+ "only by GNU and FreeBSD targets"));
bfd_set_error (bfd_error_sorry);
return FALSE;
}
diff --git a/bfd/elflink.c b/bfd/elflink.c
index e23d189b98..742254055c 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -14103,7 +14103,9 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
== SHT_FINI_ARRAY)))
|| (elf_section_data (o)->this_hdr.sh_type == SHT_NOTE
&& elf_next_in_group (o) == NULL
- && elf_linked_to_section (o) == NULL)))
+ && elf_linked_to_section (o) == NULL)
+ || ((elf_tdata (sub)->has_gnu_osabi & elf_gnu_osabi_retain)
+ && (elf_section_flags (o) & SHF_GNU_RETAIN))))
{
if (!_bfd_elf_gc_mark (info, o, gc_mark_hook))
return FALSE;
diff --git a/binutils/NEWS b/binutils/NEWS
index c0dc73d7d8..ceea7731c5 100644
--- a/binutils/NEWS
+++ b/binutils/NEWS
@@ -4,6 +4,10 @@
symbol names. In addition the --demangle=<style>, --no-demangle,
--recurse-limit and --no-recurse-limit options are also now availale.
+* Add support for the SHF_GNU_RETAIN ELF section flag.
+ This flag specifies that the section should not be garbage collected by the
+ linker.
+
Changes in 2.35:
* Changed readelf's display of symbol names when wide mode is not enabled.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 9ba4e29a65..e6ec99a2cc 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -5977,6 +5977,8 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
/* 24 */ { STRING_COMMA_LEN ("GNU_MBIND") },
/* VLE specific. */
/* 25 */ { STRING_COMMA_LEN ("VLE") },
+ /* GNU specific. */
+ /* 26 */ { STRING_COMMA_LEN ("GNU_RETAIN") },
};
if (do_section_details)
@@ -6009,7 +6011,6 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
case SHF_TLS: sindex = 9; break;
case SHF_EXCLUDE: sindex = 18; break;
case SHF_COMPRESSED: sindex = 20; break;
- case SHF_GNU_MBIND: sindex = 24; break;
default:
sindex = -1;
@@ -6061,10 +6062,26 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
if (flag == SHF_PPC_VLE)
sindex = 25;
break;
+ }
+ switch (filedata->file_header.e_ident[EI_OSABI])
+ {
+ case ELFOSABI_GNU:
+ case ELFOSABI_FREEBSD:
+ if (flag == SHF_GNU_RETAIN)
+ sindex = 26;
+ /* Fall through */
+ case ELFOSABI_NONE:
+ if (flag == SHF_GNU_MBIND)
+ /* We should not recognize SHF_GNU_MBIND for
+ ELFOSABI_NONE, but binutils as of 2019-07-23 did
+ not set the EI_OSABI header byte. */
+ sindex = 24;
+ break;
default:
break;
}
+ break;
}
if (sindex != -1)
@@ -6107,7 +6124,6 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
case SHF_TLS: *p = 'T'; break;
case SHF_EXCLUDE: *p = 'E'; break;
case SHF_COMPRESSED: *p = 'C'; break;
- case SHF_GNU_MBIND: *p = 'D'; break;
default:
if ((filedata->file_header.e_machine == EM_X86_64
@@ -6117,14 +6133,37 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
*p = 'l';
else if (filedata->file_header.e_machine == EM_ARM
&& flag == SHF_ARM_PURECODE)
- *p = 'y';
+ *p = 'y';
else if (filedata->file_header.e_machine == EM_PPC
&& flag == SHF_PPC_VLE)
- *p = 'v';
+ *p = 'v';
else if (flag & SHF_MASKOS)
{
- *p = 'o';
- sh_flags &= ~ SHF_MASKOS;
+ switch (filedata->file_header.e_ident[EI_OSABI])
+ {
+ case ELFOSABI_GNU:
+ case ELFOSABI_FREEBSD:
+ if (flag == SHF_GNU_RETAIN)
+ {
+ *p = 'R';
+ break;
+ }
+ /* Fall through */
+ case ELFOSABI_NONE:
+ if (flag == SHF_GNU_MBIND)
+ {
+ /* We should not recognize SHF_GNU_MBIND for
+ ELFOSABI_NONE, but binutils as of 2019-07-23 did
+ not set the EI_OSABI header byte. */
+ *p = 'D';
+ break;
+ }
+ /* Fall through */
+ default:
+ *p = 'o';
+ sh_flags &= ~SHF_MASKOS;
+ break;
+ }
}
else if (flag & SHF_MASKPROC)
{
diff --git a/binutils/testsuite/binutils-all/readelf-maskos-1a.d b/binutils/testsuite/binutils-all/readelf-maskos-1a.d
new file mode 100644
index 0000000000..7b27358599
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf-maskos-1a.d
@@ -0,0 +1,10 @@
+#name: Unknown SHF_MASKOS value in section
+#source: readelf-maskos.s
+#notarget: [supports_gnu_osabi] msp430-*-elf visium-*-elf
+#xfail: arm-*-elf
+#readelf: -S --wide
+# PR26722 for the arm-*-elf XFAIL
+
+#...
+ \[[ 0-9]+\] .data.retain_var.*WAo.*
+#pass
diff --git a/binutils/testsuite/binutils-all/readelf-maskos-1b.d b/binutils/testsuite/binutils-all/readelf-maskos-1b.d
new file mode 100644
index 0000000000..2cbb58a73b
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf-maskos-1b.d
@@ -0,0 +1,12 @@
+#name: -t (section details) for unknown SHF_MASKOS value in section
+#source: readelf-maskos.s
+#notarget: [supports_gnu_osabi] msp430-*-elf visium-*-elf
+#xfail: arm-*-elf
+#readelf: -S -t --wide
+# PR26722 for the arm-*-elf XFAIL
+
+#...
+ \[[ 0-9]+\] .data.retain_var
+ PROGBITS +0+ +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +0 +0 +(1|2|4|8)
+ \[00200003\]: WRITE, ALLOC, OS \(00200000\)
+#pass
diff --git a/binutils/testsuite/binutils-all/readelf-maskos.s b/binutils/testsuite/binutils-all/readelf-maskos.s
new file mode 100644
index 0000000000..d671119bca
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf-maskos.s
@@ -0,0 +1,11 @@
+ .section .data.retain_var,"0x200003"
+ .global retain_var
+ .type retain_var, %object
+retain_var:
+ .long 2
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/binutils/testsuite/binutils-all/readelf.exp b/binutils/testsuite/binutils-all/readelf.exp
index 1fb36ae5c4..9d1d496e5c 100644
--- a/binutils/testsuite/binutils-all/readelf.exp
+++ b/binutils/testsuite/binutils-all/readelf.exp
@@ -364,8 +364,15 @@ readelf_wi_test
readelf_compressed_wa_test
readelf_dump_test
-run_dump_test "pr25543"
+# These dump tests require an assembler.
+if {[which $AS] != 0} then {
+ run_dump_test "pr25543"
+ run_dump_test "retain1a"
+ run_dump_test "retain1b"
+ run_dump_test "readelf-maskos-1a"
+ run_dump_test "readelf-maskos-1b"
+}
# PR 13482 - Check for off-by-one errors when dumping .note sections.
if {![binutils_assemble $srcdir/$subdir/version.s tmpdir/version.o]} then {
diff --git a/binutils/testsuite/binutils-all/retain1.s b/binutils/testsuite/binutils-all/retain1.s
new file mode 100644
index 0000000000..f7716faabe
--- /dev/null
+++ b/binutils/testsuite/binutils-all/retain1.s
@@ -0,0 +1,104 @@
+ .global discard0
+ .section .bss.discard0,"aw"
+ .type discard0, %object
+discard0:
+ .zero 2
+
+ .global discard1
+ .section .bss.discard1,"aw"
+ .type discard1, %object
+discard1:
+ .zero 2
+
+ .global discard2
+ .section .data.discard2,"aw"
+ .type discard2, %object
+discard2:
+ .word 1
+
+ .section .bss.sdiscard0,"aw"
+ .type sdiscard0, %object
+sdiscard0:
+ .zero 2
+
+ .section .bss.sdiscard1,"aw"
+ .type sdiscard1, %object
+sdiscard1:
+ .zero 2
+
+ .section .data.sdiscard2,"aw"
+ .type sdiscard2, %object
+sdiscard2:
+ .word 1
+
+ .section .text.fndiscard0,"ax"
+ .global fndiscard0
+ .type fndiscard0, %function
+fndiscard0:
+ .word 0
+
+ .global retain0
+ .section .bss.retain0,"awR"
+ .type retain0, %object
+retain0:
+ .zero 2
+
+ .global retain1
+ .section .bss.retain1,"awR"
+ .type retain1, %object
+retain1:
+ .zero 2
+
+ .global retain2
+ .section .data.retain2,"awR"
+ .type retain2, %object
+retain2:
+ .word 1
+
+ .section .bss.sretain0,"awR"
+ .type sretain0, %object
+sretain0:
+ .zero 2
+
+ .section .bss.sretain1,"awR"
+ .type sretain1, %object
+sretain1:
+ .zero 2
+
+ .section .data.sretain2,"aRw"
+ .type sretain2, %object
+sretain2:
+ .word 1
+
+ .section .text.fnretain1,"Rax"
+ .global fnretain1
+ .type fnretain1, %function
+fnretain1:
+ .word 0
+
+ .section .text.fndiscard2,"ax"
+ .global fndiscard2
+ .type fndiscard2, %function
+fndiscard2:
+ .word 0
+
+ .section .bss.lsretain0,"awR"
+ .type lsretain0.2, %object
+lsretain0.2:
+ .zero 2
+
+ .section .bss.lsretain1,"aRw"
+ .type lsretain1.1, %object
+lsretain1.1:
+ .zero 2
+
+ .section .data.lsretain2,"aRw"
+ .type lsretain2.0, %object
+lsretain2.0:
+ .word 1
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/binutils/testsuite/binutils-all/retain1a.d b/binutils/testsuite/binutils-all/retain1a.d
new file mode 100644
index 0000000000..6397ac52ae
--- /dev/null
+++ b/binutils/testsuite/binutils-all/retain1a.d
@@ -0,0 +1,18 @@
+#name: readelf SHF_GNU_RETAIN
+#source: retain1.s
+#target: [supports_gnu_osabi]
+#readelf: -S --wide
+
+#...
+ \[[ 0-9]+\] .bss.retain0.*WAR.*
+ \[[ 0-9]+\] .bss.retain1.*WAR.*
+ \[[ 0-9]+\] .data.retain2.*WAR.*
+ \[[ 0-9]+\] .bss.sretain0.*WAR.*
+ \[[ 0-9]+\] .bss.sretain1.*WAR.*
+ \[[ 0-9]+\] .data.sretain2.*WAR.*
+ \[[ 0-9]+\] .text.fnretain1.*AXR.*
+#...
+ \[[ 0-9]+\] .bss.lsretain0.*WAR.*
+ \[[ 0-9]+\] .bss.lsretain1.*WAR.*
+ \[[ 0-9]+\] .data.lsretain2.*WAR.*
+#pass
diff --git a/binutils/testsuite/binutils-all/retain1b.d b/binutils/testsuite/binutils-all/retain1b.d
new file mode 100644
index 0000000000..12bc388ba1
--- /dev/null
+++ b/binutils/testsuite/binutils-all/retain1b.d
@@ -0,0 +1,46 @@
+#name: -t (section details) for readelf SHF_GNU_RETAIN
+#source: retain1.s
+#target: [supports_gnu_osabi]
+#readelf: -S -t --wide
+
+#...
+ \[[ 0-9]+\] .bss.retain0
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.retain1
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .data.retain2
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.sretain0
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.sretain1
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .data.sretain2
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .text.fnretain1
+#...
+ \[0+200006\]: ALLOC, EXEC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.lsretain0
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.lsretain1
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .data.lsretain2
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#pass
diff --git a/binutils/testsuite/lib/binutils-common.exp b/binutils/testsuite/lib/binutils-common.exp
index b9a1e6e4bc..a43639bafb 100644
--- a/binutils/testsuite/lib/binutils-common.exp
+++ b/binutils/testsuite/lib/binutils-common.exp
@@ -195,13 +195,15 @@ proc match_target { target } {
# True if the ELF target supports setting the ELF header OSABI field
# to ELFOSABI_GNU or ELFOSABI_FREEBSD, a requirement for STT_GNU_IFUNC
-# symbol and SHF_GNU_MBIND section support.
+# symbol and SHF_GNU_MBIND or SHF_GNU_RETAIN section support.
#
# This generally depends on the target OS only, however there are a
# number of exceptions for bare metal targets as follows. The MSP430
# and Visium targets set OSABI to ELFOSABI_STANDALONE. Likewise
# non-EABI ARM targets set OSABI to ELFOSABI_ARM
#
+# Non-Linux HPPA defaults to ELFOSABI_HPUX.
+#
# Note that some TI C6X targets use ELFOSABI_C6000_* but one doesn't,
# so we don't try to sort out tic6x here. (The effect is that linker
# testcases will generally need to exclude tic6x or use a -m option.)
@@ -227,6 +229,7 @@ proc supports_gnu_osabi {} {
}
if { [istarget "arm*-*-*"]
|| [istarget "msp430-*-*"]
+ || [istarget "hppa-unknown-elf"]
|| [istarget "visium-*-*"] } {
return 0
}
diff --git a/gas/NEWS b/gas/NEWS
index 1107725ea6..33005b5904 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -30,6 +30,11 @@
* Configure with --enable-x86-used-note by default for Linux/x86.
+* Add support for the "R" flag in the .section directive.
+ This flag requires ELFOSABI_GNU or ELFOSABI_FREEBSD, and applies the
+ ELF SHF_GNU_RETAIN flag to the specified section. This flag specifies
+ the section should not be garbage collected by the linker.
+
Changes in 2.35:
* X86 NaCl target support is removed.
diff --git a/gas/config/obj-elf.c b/gas/config/obj-elf.c
index f061ea61f3..6586478975 100644
--- a/gas/config/obj-elf.c
+++ b/gas/config/obj-elf.c
@@ -529,9 +529,9 @@ get_section_by_match (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *inf)
const char *group_name = elf_group_name (sec);
const char *linked_to_symbol_name
= sec->map_head.linked_to_symbol_name;
- unsigned int info = elf_section_data (sec)->this_hdr.sh_info;
+ unsigned int sh_info = elf_section_data (sec)->this_hdr.sh_info;
- return (info == match->info
+ return (sh_info == match->sh_info
&& ((bfd_section_flags (sec) & SEC_ASSEMBLER_SECTION_ID)
== (match->flags & SEC_ASSEMBLER_SECTION_ID))
&& sec->section_id == match->section_id
@@ -740,7 +740,7 @@ obj_elf_change_section (const char *name,
type = bfd_elf_get_default_section_type (flags);
elf_section_type (sec) = type;
elf_section_flags (sec) = attr;
- elf_section_data (sec)->this_hdr.sh_info = match_p->info;
+ elf_section_data (sec)->this_hdr.sh_info = match_p->sh_info;
/* Prevent SEC_HAS_CONTENTS from being inadvertently set. */
if (type == SHT_NOBITS)
@@ -798,7 +798,10 @@ obj_elf_change_section (const char *name,
& (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
| SEC_EXCLUDE | SEC_SORT_ENTRIES | SEC_MERGE | SEC_STRINGS
| SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD
- | SEC_THREAD_LOCAL)))
+ | SEC_THREAD_LOCAL))
+ || ((elf_tdata (stdoutput)->has_gnu_osabi & elf_gnu_osabi_retain)
+ && ((elf_section_flags (old_sec) ^ match_p->sh_flags)
+ & SHF_GNU_RETAIN)))
{
if (ssect != NULL)
as_warn (_("ignoring changed section attributes for %s"), name);
@@ -861,6 +864,9 @@ obj_elf_parse_section_letters (char *str, size_t len,
case 'd':
*gnu_attr |= SHF_GNU_MBIND;
break;
+ case 'R':
+ *gnu_attr |= SHF_GNU_RETAIN;
+ break;
case '?':
*is_clone = TRUE;
break;
@@ -890,8 +896,32 @@ obj_elf_parse_section_letters (char *str, size_t len,
if (ISDIGIT (*str))
{
char * end;
+ struct elf_backend_data *bed;
+ bfd_vma numeric_flags = strtoul (str, &end, 0);
+
+ attr |= numeric_flags;
+
+ bed = (struct elf_backend_data *)
+ get_elf_backend_data (stdoutput);
+
+ if (bed->elf_osabi == ELFOSABI_NONE
+ || bed->elf_osabi == ELFOSABI_STANDALONE
+ || bed->elf_osabi == ELFOSABI_GNU
+ || bed->elf_osabi == ELFOSABI_FREEBSD)
+ {
+ /* Add flags in the SHF_MASKOS range to gnu_attr for
+ OSABIs that support those flags.
+ Also adding the flags for ELFOSABI_{NONE,STANDALONE}
+ allows them to be validated later in obj_elf_section.
+ We can't just always set these bits in gnu_attr for
+ all OSABIs, since Binutils does not recognize all
+ SHF_MASKOS bits for non-GNU OSABIs. It's therefore
+ possible that numeric flags are being used to set bits
+ in the SHF_MASKOS range for those targets, and we
+ don't want assembly to fail in those situations. */
+ *gnu_attr |= (numeric_flags & SHF_MASKOS);
+ }
- attr |= strtoul (str, & end, 0);
/* Update str and len, allowing for the fact that
we will execute str++ and len-- below. */
end --;
@@ -1287,18 +1317,21 @@ obj_elf_section (int push)
if (ISDIGIT (* input_line_pointer))
{
char *t = input_line_pointer;
- match.info = strtoul (input_line_pointer,
+ match.sh_info = strtoul (input_line_pointer,
&input_line_pointer, 0);
- if (match.info == (unsigned int) -1)
+ if (match.sh_info == (unsigned int) -1)
{
as_warn (_("unsupported mbind section info: %s"), t);
- match.info = 0;
+ match.sh_info = 0;
}
}
else
input_line_pointer = save;
}
+ if ((gnu_attr & SHF_GNU_RETAIN) != 0)
+ match.sh_flags |= SHF_GNU_RETAIN;
+
if (*input_line_pointer == ',')
{
char *save = input_line_pointer;
@@ -1387,26 +1420,39 @@ obj_elf_section (int push)
done:
demand_empty_rest_of_line ();
- obj_elf_change_section (name, type, attr, entsize, &match, linkonce,
- push);
-
- if ((gnu_attr & SHF_GNU_MBIND) != 0)
+ if ((gnu_attr & (SHF_GNU_MBIND | SHF_GNU_RETAIN)) != 0)
{
struct elf_backend_data *bed;
+ bfd_boolean mbind_p = (gnu_attr & SHF_GNU_MBIND) != 0;
- if ((attr & SHF_ALLOC) == 0)
+ if (mbind_p && (attr & SHF_ALLOC) == 0)
as_bad (_("SHF_ALLOC isn't set for GNU_MBIND section: %s"), name);
bed = (struct elf_backend_data *) get_elf_backend_data (stdoutput);
- if (bed->elf_osabi == ELFOSABI_NONE)
- bed->elf_osabi = ELFOSABI_GNU;
- else if (bed->elf_osabi != ELFOSABI_GNU
- && bed->elf_osabi != ELFOSABI_FREEBSD)
- as_bad (_("GNU_MBIND section is supported only by GNU "
- "and FreeBSD targets"));
- elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_mbind;
+
+ if (bed->elf_osabi != ELFOSABI_GNU
+ && bed->elf_osabi != ELFOSABI_FREEBSD
+ && bed->elf_osabi != ELFOSABI_NONE)
+ {
+ as_bad (_("%s section is supported only by GNU and FreeBSD targets"),
+ mbind_p ? "GNU_MBIND" : "GNU_RETAIN");
+ }
+ else
+ {
+ if (bed->elf_osabi == ELFOSABI_NONE)
+ bed->elf_osabi = ELFOSABI_GNU;
+
+ if (mbind_p)
+ elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_mbind;
+ if ((gnu_attr & SHF_GNU_RETAIN) != 0)
+ elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_retain;
+
+ attr |= gnu_attr;
+ }
}
- elf_section_flags (now_seg) |= gnu_attr;
+
+ obj_elf_change_section (name, type, attr, entsize, &match, linkonce,
+ push);
if (linked_to_section_index != -1UL)
{
diff --git a/gas/config/obj-elf.h b/gas/config/obj-elf.h
index 4f29572eef..0a91ed462f 100644
--- a/gas/config/obj-elf.h
+++ b/gas/config/obj-elf.h
@@ -106,8 +106,9 @@ struct elf_section_match
{
const char * group_name;
const char * linked_to_symbol_name;
- unsigned int info;
unsigned int section_id;
+ unsigned int sh_info; /* ELF section information. */
+ bfd_vma sh_flags; /* ELF section flags. */
flagword flags;
};
diff --git a/gas/doc/as.texi b/gas/doc/as.texi
index 4d5294552a..e92432a8bd 100644
--- a/gas/doc/as.texi
+++ b/gas/doc/as.texi
@@ -6657,6 +6657,9 @@ section is a member of a section group
section is used for thread-local-storage
@item ?
section is a member of the previously-current section's group, if any
+@item R
+retained section (apply SHF_GNU_RETAIN to prevent linker garbage
+collection, GNU ELF extension)
@item @code{<number>}
a numeric value indicating the bits to be set in the ELF section header's flags
field. Note - if one or more of the alphabetic characters described above is
diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
index 9d75154483..49d5a47959 100644
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@@ -261,8 +261,11 @@ if { [is_elf_format] } then {
run_dump_test "section19"
run_dump_test "section20"
run_dump_test "section21"
+ run_dump_test "section22"
+ run_dump_test "section23a"
+ run_dump_test "section23b"
+ run_dump_test "section24"
run_dump_test "sh-link-zero"
-
run_dump_test "dwarf2-1" $dump_opts
run_dump_test "dwarf2-2" $dump_opts
run_dump_test "dwarf2-3" $dump_opts
diff --git a/gas/testsuite/gas/elf/section10.d b/gas/testsuite/gas/elf/section10.d
index 554a791f1d..6aa7b088b1 100644
--- a/gas/testsuite/gas/elf/section10.d
+++ b/gas/testsuite/gas/elf/section10.d
@@ -18,7 +18,7 @@
#...
[ ]*\[.*\][ ]+sec3
[ ]*PROGBITS.*
-[ ]*\[.*fefff030\]: MERGE, STRINGS,.* EXCLUDE, OS \(.*ef00000\), PROC \(.*[3467]0000000\), UNKNOWN \(0+0ff000\)
+[ ]*\[.*fedff030\]: MERGE, STRINGS,.* EXCLUDE, OS \(.*ed00000\), PROC \(.*[3467]0000000\), UNKNOWN \(0+0ff000\)
#...
[ ]*\[.*\][ ]+sec4
[ ]*LOOS\+0x11[ ].*
@@ -26,7 +26,7 @@
#...
[ ]*\[.*\][ ]+sec5
[ ]*LOUSER\+0x9[ ].*
-[ ]*\[.*feff0000\]:.* EXCLUDE, OS \(.*ef00000\), PROC \(.*[3467]0000000\), UNKNOWN \(.*f0000\)
+[ ]*\[.*fedf0000\]:.* EXCLUDE, OS \(.*ed00000\), PROC \(.*[3467]0000000\), UNKNOWN \(.*f0000\)
[ ]*\[.*\][ ]+.data.foo
[ ]*LOUSER\+0x7f000000[ ].*
[ ]*\[0+003\]: WRITE, ALLOC
diff --git a/gas/testsuite/gas/elf/section10.s b/gas/testsuite/gas/elf/section10.s
index 29f1184523..d52b3458fb 100644
--- a/gas/testsuite/gas/elf/section10.s
+++ b/gas/testsuite/gas/elf/section10.s
@@ -7,7 +7,7 @@
.word 2
# Make sure that specifying further arguments to .sections is still supported
- .section sec3, "0xfefff000MS", %progbits, 32
+ .section sec3, "0xfedff000MS", %progbits, 32
.word 3
# Make sure that extra flags can be set for well known sections as well.
@@ -19,7 +19,7 @@
.word 5
# Test both together, with a quoted type value.
- .section sec5, "0xfeff0000", "0x80000009"
+ .section sec5, "0xfedf0000", "0x80000009"
.word 6
# Test that declaring an extended version of a known special section works.
diff --git a/gas/testsuite/gas/elf/section22.d b/gas/testsuite/gas/elf/section22.d
new file mode 100644
index 0000000000..8aa7fcfc34
--- /dev/null
+++ b/gas/testsuite/gas/elf/section22.d
@@ -0,0 +1,19 @@
+#readelf: -h -S --wide
+#name: SHF_GNU_RETAIN sections 22
+#notarget: ![supports_gnu_osabi]
+
+#...
+ +OS/ABI: +UNIX - GNU
+#...
+ \[..\] .text.discard0[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX.*
+#...
+ \[..\] .data.discard1[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA.*
+#...
+ \[..\] .bss.discard2[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA.*
+#...
+ \[..\] .bss.retain0[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
+#...
+ \[..\] .data.retain1[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
+#...
+ \[..\] .text.retain2[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR.*
+#pass
diff --git a/gas/testsuite/gas/elf/section22.s b/gas/testsuite/gas/elf/section22.s
new file mode 100644
index 0000000000..66ed990e57
--- /dev/null
+++ b/gas/testsuite/gas/elf/section22.s
@@ -0,0 +1,34 @@
+ .section .text.discard0,"ax",%progbits
+ .global discard0
+ .type discard0, %function
+discard0:
+ .word 0
+
+ .section .data.discard1,"aw"
+ .global discard1
+ .type discard1, %object
+discard1:
+ .word 1
+
+ .section .bss.discard2,"aw"
+ .global discard2
+ .type discard2, %object
+discard2:
+ .zero 2
+
+ .section .bss.retain0,"awR",%nobits
+ .global retain0
+ .type retain0, %object
+retain0:
+ .zero 2
+
+ .section .data.retain1,"awR",%progbits
+ .type retain1, %object
+retain1:
+ .word 1
+
+ .section .text.retain2,"axR",%progbits
+ .global retain2
+ .type retain2, %function
+retain2:
+ .word 0
diff --git a/gas/testsuite/gas/elf/section23.s b/gas/testsuite/gas/elf/section23.s
new file mode 100644
index 0000000000..d671119bca
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23.s
@@ -0,0 +1,11 @@
+ .section .data.retain_var,"0x200003"
+ .global retain_var
+ .type retain_var, %object
+retain_var:
+ .long 2
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/gas/testsuite/gas/elf/section23a.d b/gas/testsuite/gas/elf/section23a.d
new file mode 100644
index 0000000000..1d850d9e8e
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23a.d
@@ -0,0 +1,11 @@
+#name: SHF_GNU_RETAIN set with numeric flag value in .section
+#source: section23.s
+#target: [supports_gnu_osabi]
+#readelf: -h -S --wide
+
+#...
+ +OS/ABI: +UNIX - GNU
+#...
+ \[..\] .data.retain_var[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
+#pass
+
diff --git a/gas/testsuite/gas/elf/section23b.d b/gas/testsuite/gas/elf/section23b.d
new file mode 100644
index 0000000000..c85200e5ff
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23b.d
@@ -0,0 +1,6 @@
+#name: SHF_GNU_RETAIN set with numeric flag value in .section for non-GNU OSABI target
+#source: section23.s
+#error_output: section23b.err
+#target: msp430-*-elf visium-*-elf
+
+# This test only runs for targets which set ELFOSABI_STANDALONE.
diff --git a/gas/testsuite/gas/elf/section23b.err b/gas/testsuite/gas/elf/section23b.err
new file mode 100644
index 0000000000..83de60c397
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23b.err
@@ -0,0 +1,2 @@
+.*: Assembler messages:
+.*:1: Error: GNU_RETAIN section is supported only by GNU and FreeBSD targets
diff --git a/gas/testsuite/gas/elf/section24.d b/gas/testsuite/gas/elf/section24.d
new file mode 100644
index 0000000000..5ee4aee3af
--- /dev/null
+++ b/gas/testsuite/gas/elf/section24.d
@@ -0,0 +1,18 @@
+#name: Warn for SHF_GNU_RETAIN set on existing section
+#notarget: ![supports_gnu_osabi] rx-*-*
+#readelf: -h -S --wide
+#warning_output: section24.l
+# rx-*-* does not automatically create a ".text" section when starting assembly.
+
+#...
+ +OS/ABI: +UNIX - GNU
+#...
+ \[..\] .text[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX .*
+#...
+ \[..\] .text[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR .*
+#...
+ \[..\] .text.foo[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR .*
+#...
+ \[..\] .text.bar[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX .*
+#pass
+
diff --git a/gas/testsuite/gas/elf/section24.l b/gas/testsuite/gas/elf/section24.l
new file mode 100644
index 0000000000..e0ea36078c
--- /dev/null
+++ b/gas/testsuite/gas/elf/section24.l
@@ -0,0 +1,4 @@
+[^:]*: Assembler messages:
+[^:]*:4: Warning: ignoring changed section attributes for .text
+[^:]*:20: Warning: ignoring changed section attributes for .text.foo
+[^:]*:30: Warning: ignoring changed section attributes for .text.bar
diff --git a/gas/testsuite/gas/elf/section24.s b/gas/testsuite/gas/elf/section24.s
new file mode 100644
index 0000000000..deaff0a323
--- /dev/null
+++ b/gas/testsuite/gas/elf/section24.s
@@ -0,0 +1,32 @@
+/* The default .text section automatically created by the assembler does not
+ have the SHF_GNU_RETAIN flag set, so the "R" flag cannot be used with that,
+ or any other, default section. */
+ .section .text,"axR",%progbits
+retain_bad:
+ .word 0
+
+/* A unique .text section with SHF_GNU_RETAIN applied can be created. */
+ .section .text,"axR",%progbits,unique,0
+retain_good:
+ .word 0
+
+/* SHF_GNU_RETAIN can be applied to a new section. */
+ .section .text.foo,"axR",%progbits
+foo_retain:
+ .word 0
+
+/* If the section is used again without SHF_GNU_RETAIN, a warning should be
+ emitted. */
+ .section .text.foo,"ax",%progbits
+foo:
+ .word 0
+
+ .section .text.bar,"ax",%progbits
+bar:
+ .word 0
+
+/* SHF_GNU_RETAIN cannot be applied to a section which was already explicitly
+ declared without SHF_GNU_RETAIN set. */
+ .section .text.bar,"axR",%progbits
+bar_retain:
+ .word 0
diff --git a/include/elf/common.h b/include/elf/common.h
index 571e21af29..c01e562c78 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -554,6 +554,7 @@
/* #define SHF_MASKOS 0x0F000000 *//* OS-specific semantics */
#define SHF_MASKOS 0x0FF00000 /* New value, Oct 4, 1999 Draft */
#define SHF_GNU_BUILD_NOTE (1 << 20) /* Section contains GNU BUILD ATTRIBUTE notes. */
+#define SHF_GNU_RETAIN (1 << 21) /* Section should not be garbage collected by the linker. */
#define SHF_MASKPROC 0xF0000000 /* Processor-specific semantics */
/* This used to be implemented as a processor specific section flag.
diff --git a/ld/NEWS b/ld/NEWS
index e4ae43b257..c103bcebc4 100644
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -15,6 +15,10 @@
unless you are working on a project that has its own analogue
of symbol tables that are not reflected in the ELF symtabs.
+* Add support for the SHF_GNU_RETAIN ELF section flag.
+ This flag specifies that the section should not be garbage collected by the
+ linker.
+
Changes in 2.35:
* X86 NaCl target support is removed.
diff --git a/ld/ld.texi b/ld/ld.texi
index ee592df6c2..849006f0fb 100644
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -1787,6 +1787,9 @@ specified either by one of the options @samp{--entry},
@samp{--undefined}, or @samp{--gc-keep-exported} or by a @code{ENTRY}
command in the linker script.
+As a GNU extension, ELF input sections marked with the
+@code{SHF_GNU_RETAIN} flag will not be garbage collected.
+
@kindex --print-gc-sections
@kindex --no-print-gc-sections
@cindex garbage collection
@@ -5232,6 +5235,10 @@ The special output section name @samp{/DISCARD/} may be used to discard
input sections. Any input sections which are assigned to an output
section named @samp{/DISCARD/} are not included in the output file.
+This can be used to discard input sections marked with the ELF flag
+@code{SHF_GNU_RETAIN}, which would otherwise have been saved from linker
+garbage collection.
+
Note, sections that match the @samp{/DISCARD/} output section will be
discarded even if they are in an ELF section group which has other
members which are not being discarded. This is deliberate.
diff --git a/ld/testsuite/ld-elf/elf.exp b/ld/testsuite/ld-elf/elf.exp
index f2ff0397c7..bd06ab0d39 100644
--- a/ld/testsuite/ld-elf/elf.exp
+++ b/ld/testsuite/ld-elf/elf.exp
@@ -119,6 +119,17 @@ if { [istarget "i?86-*-*"] || [istarget "x86_64-*-*"] } {
set ASFLAGS "$ASFLAGS -mx86-used-note=no"
}
+# Build libraries required for SHF_GNU_RETAIN tests.
+if { [check_gc_sections_available] && [supports_gnu_osabi] } {
+ run_ld_link_tests [list \
+ [list "Build libretain5.a" "" "" "" \
+ {retain5lib.s} {} "libretain5.a"] \
+ [list "Build libretain6.a" "" "" "" \
+ {retain6lib.s} {} "libretain6.a"] \
+ ]
+}
+
+
set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
foreach t $test_list {
# We need to strip the ".d", but can leave the dirname.
diff --git a/ld/testsuite/ld-elf/retain1.s b/ld/testsuite/ld-elf/retain1.s
new file mode 100644
index 0000000000..f7716faabe
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain1.s
@@ -0,0 +1,104 @@
+ .global discard0
+ .section .bss.discard0,"aw"
+ .type discard0, %object
+discard0:
+ .zero 2
+
+ .global discard1
+ .section .bss.discard1,"aw"
+ .type discard1, %object
+discard1:
+ .zero 2
+
+ .global discard2
+ .section .data.discard2,"aw"
+ .type discard2, %object
+discard2:
+ .word 1
+
+ .section .bss.sdiscard0,"aw"
+ .type sdiscard0, %object
+sdiscard0:
+ .zero 2
+
+ .section .bss.sdiscard1,"aw"
+ .type sdiscard1, %object
+sdiscard1:
+ .zero 2
+
+ .section .data.sdiscard2,"aw"
+ .type sdiscard2, %object
+sdiscard2:
+ .word 1
+
+ .section .text.fndiscard0,"ax"
+ .global fndiscard0
+ .type fndiscard0, %function
+fndiscard0:
+ .word 0
+
+ .global retain0
+ .section .bss.retain0,"awR"
+ .type retain0, %object
+retain0:
+ .zero 2
+
+ .global retain1
+ .section .bss.retain1,"awR"
+ .type retain1, %object
+retain1:
+ .zero 2
+
+ .global retain2
+ .section .data.retain2,"awR"
+ .type retain2, %object
+retain2:
+ .word 1
+
+ .section .bss.sretain0,"awR"
+ .type sretain0, %object
+sretain0:
+ .zero 2
+
+ .section .bss.sretain1,"awR"
+ .type sretain1, %object
+sretain1:
+ .zero 2
+
+ .section .data.sretain2,"aRw"
+ .type sretain2, %object
+sretain2:
+ .word 1
+
+ .section .text.fnretain1,"Rax"
+ .global fnretain1
+ .type fnretain1, %function
+fnretain1:
+ .word 0
+
+ .section .text.fndiscard2,"ax"
+ .global fndiscard2
+ .type fndiscard2, %function
+fndiscard2:
+ .word 0
+
+ .section .bss.lsretain0,"awR"
+ .type lsretain0.2, %object
+lsretain0.2:
+ .zero 2
+
+ .section .bss.lsretain1,"aRw"
+ .type lsretain1.1, %object
+lsretain1.1:
+ .zero 2
+
+ .section .data.lsretain2,"aRw"
+ .type lsretain2.0, %object
+lsretain2.0:
+ .word 1
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain1a.d b/ld/testsuite/ld-elf/retain1a.d
new file mode 100644
index 0000000000..75abb9856c
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain1a.d
@@ -0,0 +1,28 @@
+#name: SHF_GNU_RETAIN 1a
+#source: retain1.s
+#ld: -e _start --gc-sections
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . fnretain1
+#...
+[0-9a-f]+ . lsretain0.2
+#...
+[0-9a-f]+ . lsretain1.1
+#...
+[0-9a-f]+ . lsretain2.0
+#...
+[0-9a-f]+ . retain0
+#...
+[0-9a-f]+ . retain1
+#...
+[0-9a-f]+ . retain2
+#...
+[0-9a-f]+ . sretain0
+#...
+[0-9a-f]+ . sretain1
+#...
+[0-9a-f]+ . sretain2
+#pass
diff --git a/ld/testsuite/ld-elf/retain1b.d b/ld/testsuite/ld-elf/retain1b.d
new file mode 100644
index 0000000000..815c0150f5
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain1b.d
@@ -0,0 +1,11 @@
+#name: SHF_GNU_RETAIN 1b
+#source: retain1.s
+#ld: -e _start --gc-sections
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#nm: -n
+
+#failif
+#...
+[0-9a-f]+ . .*discard.*
+#...
diff --git a/ld/testsuite/ld-elf/retain2.d b/ld/testsuite/ld-elf/retain2.d
new file mode 100644
index 0000000000..11efd6ddb8
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain2.d
@@ -0,0 +1,6 @@
+#name: SHF_GNU_RETAIN 2 (remove SHF_GNU_RETAIN sections by placing in /DISCARD/)
+#source: retain1.s
+#ld: -e _start -Map=retain2.map --gc-sections --script=retain2.ld
+#map: retain2.map
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
diff --git a/ld/testsuite/ld-elf/retain2.ld b/ld/testsuite/ld-elf/retain2.ld
new file mode 100644
index 0000000000..8ef982753c
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain2.ld
@@ -0,0 +1,7 @@
+SECTIONS
+{
+ /DISCARD/ :
+ {
+ *(.text.fnretain1)
+ }
+}
diff --git a/ld/testsuite/ld-elf/retain2.map b/ld/testsuite/ld-elf/retain2.map
new file mode 100644
index 0000000000..4028aa1f58
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain2.map
@@ -0,0 +1,32 @@
+# Test that .text.fnretain1, which has the SHF_GNU_RETAIN flag, can still be
+# explicitly discarded from the output file.
+
+#...
+Discarded input sections
+
+ .text.*
+#...
+ .data.*
+#...
+ .bss.*
+#...
+ .bss.discard0.*
+#...
+ .bss.discard1.*
+#...
+ .data.discard2.*
+#...
+ .bss.sdiscard0.*
+#...
+ .bss.sdiscard1.*
+#...
+ .data.sdiscard2.*
+#...
+ .text.fndiscard0.*
+#...
+ .text.fnretain1.*
+#...
+ .text.fndiscard2.*
+#...
+Memory Configuration
+#pass
diff --git a/ld/testsuite/ld-elf/retain3.d b/ld/testsuite/ld-elf/retain3.d
new file mode 100644
index 0000000000..911f5b7594
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain3.d
@@ -0,0 +1,12 @@
+#name: SHF_GNU_RETAIN 3 (keep sections referenced by retained sections)
+#source: retain3.s
+#ld: -e _start --gc-sections
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . bar
+#...
+[0-9a-f]+ . foo
+#pass
diff --git a/ld/testsuite/ld-elf/retain3.s b/ld/testsuite/ld-elf/retain3.s
new file mode 100644
index 0000000000..ce315cbaa6
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain3.s
@@ -0,0 +1,19 @@
+/* The retention of bar should also prevent foo from being gc'ed, since bar
+ references foo. */
+ .section .text.foo,"ax"
+ .global foo
+ .type foo, %function
+foo:
+ .word 0
+
+ .section .text.bar,"axR"
+ .global bar
+ .type bar, %function
+bar:
+ .long foo
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain4.d b/ld/testsuite/ld-elf/retain4.d
new file mode 100644
index 0000000000..e94898d681
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain4.d
@@ -0,0 +1,10 @@
+#name: SHF_GNU_RETAIN 4 (keep orphaned sections when not discarding)
+#source: retain4.s
+#ld: -e _start --gc-sections --orphan-handling=place
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . orphaned_fn
+#pass
diff --git a/ld/testsuite/ld-elf/retain4.s b/ld/testsuite/ld-elf/retain4.s
new file mode 100644
index 0000000000..9f350cd3b2
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain4.s
@@ -0,0 +1,13 @@
+/* A section which doesn't match any linker script input section rules but
+ has SHF_GNU_RETAIN applied should not be garbage collected. */
+ .section .orphaned_section,"axR"
+ .global orphaned_fn
+ .type orphaned_fn, %function
+orphaned_fn:
+ .word 0
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain5.d b/ld/testsuite/ld-elf/retain5.d
new file mode 100644
index 0000000000..378799599e
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5.d
@@ -0,0 +1,12 @@
+#name: SHF_GNU_RETAIN 5 (don't pull SHF_GNU_RETAIN section out of lib)
+#source: retain5main.s
+#ld: --gc-sections -e _start --print-gc-sections -Ltmpdir -lretain5 -Map=retain5.map
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#map: retain5.map
+#DUMPPROG: nm
+
+#failif
+#...
+[0-9a-f]+ . foo
+#...
diff --git a/ld/testsuite/ld-elf/retain5.map b/ld/testsuite/ld-elf/retain5.map
new file mode 100644
index 0000000000..6b97c2a220
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5.map
@@ -0,0 +1,5 @@
+# Check that the library was actually loaded to catch any false PASS.
+
+#...
+LOAD tmpdir/libretain5.a
+#pass
diff --git a/ld/testsuite/ld-elf/retain5lib.s b/ld/testsuite/ld-elf/retain5lib.s
new file mode 100644
index 0000000000..4e83731719
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5lib.s
@@ -0,0 +1,6 @@
+/* The link will fail if foo is included because undefined_sym is not defined. */
+ .section .text.foo,"axR"
+ .global foo
+ .type foo, %function
+foo:
+ .long undefined_sym
diff --git a/ld/testsuite/ld-elf/retain5main.s b/ld/testsuite/ld-elf/retain5main.s
new file mode 100644
index 0000000000..89a7784d13
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5main.s
@@ -0,0 +1,5 @@
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain6a.d b/ld/testsuite/ld-elf/retain6a.d
new file mode 100644
index 0000000000..92872deffc
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6a.d
@@ -0,0 +1,14 @@
+#name: SHF_GNU_RETAIN 6a (pull section out of lib required by SHF_GNU_RETAIN section)
+#source: retain6main.s
+#ld: --gc-sections -e _start -u bar -Ltmpdir -lretain6
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . bar
+#...
+[0-9a-f]+ . retain_from_lib
+#...
+[0-9a-f]+ . retained_fn
+#pass
diff --git a/ld/testsuite/ld-elf/retain6b.d b/ld/testsuite/ld-elf/retain6b.d
new file mode 100644
index 0000000000..a797bf7837
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6b.d
@@ -0,0 +1,11 @@
+#name: SHF_GNU_RETAIN 6b (pull section out of lib required by SHF_GNU_RETAIN section)
+#source: retain6main.s
+#ld: --gc-sections -e _start -u bar -Ltmpdir -lretain6
+#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#failif
+#...
+[0-9a-f]+ . .*discard.*
+#...
diff --git a/ld/testsuite/ld-elf/retain6lib.s b/ld/testsuite/ld-elf/retain6lib.s
new file mode 100644
index 0000000000..a393dbac61
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6lib.s
@@ -0,0 +1,17 @@
+ .section .text.bar,"ax"
+ .global bar
+ .type bar, %function
+bar:
+ .word 0
+
+ .section .text.retain_from_lib,"axR"
+ .global retain_from_lib
+ .type retain_from_lib, %function
+retain_from_lib:
+ .word 0
+
+ .section .text.discard_from_lib,"ax"
+ .global discard_from_lib
+ .type discard_from_lib, %function
+discard_from_lib:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain6main.s b/ld/testsuite/ld-elf/retain6main.s
new file mode 100644
index 0000000000..a66c5b3247
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6main.s
@@ -0,0 +1,13 @@
+/* Undefined symbol reference in retained section .text.retained_fn requires
+ symbol definition to be pulled out of library. */
+ .section .text.retained_fn,"axR"
+ .global retained_fn
+ .type retained_fn, %function
+retained_fn:
+ .long bar
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
--
2.28.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v3] Support SHF_GNU_RETAIN ELF Section Flag
2020-10-09 10:59 [PATCH v3] Support SHF_GNU_RETAIN ELF Section Flag Jozef Lawrynowicz
@ 2020-10-19 19:47 ` Jozef Lawrynowicz
0 siblings, 0 replies; 2+ messages in thread
From: Jozef Lawrynowicz @ 2020-10-19 19:47 UTC (permalink / raw)
To: binutils
[-- Attachment #1: Type: text/plain, Size: 58001 bytes --]
Ping for this with a small amendment - removed the unnecessary skip
list in the LD tests.
On Fri, Oct 09, 2020 at 11:59:47AM +0100, Jozef Lawrynowicz wrote:
> The attached patch is version 3 of the SHF_GNU_RETAIN patch that was
> previously discussed here:
>
> Version 1:
> https://sourceware.org/pipermail/binutils/2020-September/113406.html
> Version 2:
> https://sourceware.org/pipermail/binutils/2020-October/113559.html
>
> The following changes have been made since version 2:
> - Removed "if it is unused" phrase from SHF_GNU_RETAIN definition.
> The definition now reads:
> "The link editor should not garbage collect the section."
> - Aligned OSABI error messages in bfd/elf.c with those in
> gas/config/obj-elf.c.
> - Added OSABI checks before SHF_GNU_RETAIN is used in bfd/elflink.c.
> - Added OSABI checks and new tests before SHF_GNU_RETAIN and
> SHF_GNU_MBIND are used in binutils/readelf.c.
> - Removed support in GAS for unique sections to be created with the same
> name, but different states for SHF_GNU_RETAIN. This exception is not
> required for SHF_GNU_RETAIN support.
> - Added warning/error message when SHF_GNU_RETAIN state is not
> consistent when changing sections. Added tests for this.
> - Added support for flags in the SHF_MASKOS range to be set with numeric
> values to the flags argument of the .section directive. Added tests
> for this.
>
> I've successfully regtested the patch for the Binutils, GAS and LD
> testsuites for the following targets:
>
> aarch64-elf arc-elf arm-eabi arm-elf avr-elf bfin-elf cr16-elf cris-elf
> crx-elf csky-elf d10v-elf d30v-elf dlx-elf epiphany-elf fr30-elf frv-elf
> ft32-elf h8300-elf hppa-elf i386-elf ip2k-elf iq2000-elf lm32-elf
> m32c-elf m32r-elf m68hc11-elf m68hc12-elf m68k-elf mcore-elf mep-elf
> metag-elf microblaze-elf mips-elf moxie-elf msp430-elf mt-elf nios2-elf
> or1k-elf pj-elf ppc-elf pru-elf riscv-elf rl78-elf rx-elf s12z-elf
> score-elf sh-elf sparc-elf spu-elf tic6x-elf tilegx-elf tilepro-elf
> v850-elf visium-elf wasm32-elf xgate-elf xstormy16-elf xtensa-elf
> z80-elf.
>
> Ok to apply?
>
> Thanks,
> Jozef
> From 9709145da0644b6657a892ad8e513ace81359c7d Mon Sep 17 00:00:00 2001
> From: Jozef Lawrynowicz <jozef.l@mittosystems.com>
> Date: Fri, 9 Oct 2020 11:52:55 +0100
> Subject: [PATCH] Support SHF_GNU_RETAIN ELF section flag
>
> The SHF_GNU_RETAIN section flag is an extension to the GNU ELF OSABI.
> It is defined as follows:
>
> =======================================================================
> Section Attribute Flags
> +-------------------------------------+
> | Name | Value |
> +-------------------------------------+
> | SHF_GNU_RETAIN | 0x200000 (1 << 21) |
> +-------------------------------------+
>
> SHF_GNU_RETAIN
> The link editor should not garbage collect the section.
>
> =======================================================================
>
> Note that there is not a direct mapping of SHF_GNU_RETAIN to the BFD
> section flag SEC_KEEP. This would prevent the user being able to
> explicitly remove an SHF_GNU_RETAIN section by placing it in /DISCARD/.
>
> bfd/ChangeLog:
>
> 2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
> H.J. Lu <hongjiu.lu@intel.com>
>
> * elf-bfd.h (enum elf_gnu_osabi): Add elf_gnu_osabi_retain.
> (struct elf_obj_tdata): Increase has_gnu_osabi to 4 bits.
> * elf.c (_bfd_elf_make_section_from_shdr): Set elf_gnu_osabi_retain
> for SHF_GNU_RETAIN.
> (_bfd_elf_final_write_processing): Report if SHF_GNU_RETAIN is
> not supported by the OSABI.
> Adjust error messages.
> * elflink.c (bfd_elf_gc_sections): gc_mark the section if
> SHF_GNU_RETAIN is set.
>
> binutils/ChangeLog:
>
> 2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
>
> * NEWS: Announce SHF_GNU_RETAIN.
> * readelf.c (get_elf_section_flags): Handle SHF_GNU_RETAIN.
> Recognize SHF_GNU_RETAIN and SHF_GNU_MBIND only for supported OSABIs.
> * testsuite/binutils-all/readelf.exp: Run new tests.
> Don't run run_dump_test when there isn't an assembler available.
> * testsuite/lib/binutils-common.exp (supports_gnu_osabi): Adjust
> comment.
> * testsuite/binutils-all/readelf-maskos-1a.d: New test.
> * testsuite/binutils-all/readelf-maskos-1b.d: New test.
> * testsuite/binutils-all/readelf-maskos.s: New test.
> * testsuite/binutils-all/retain1.s: New test.
> * testsuite/binutils-all/retain1a.d: New test.
> * testsuite/binutils-all/retain1b.d: New test.
>
> gas/ChangeLog:
>
> 2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
> H.J. Lu <hongjiu.lu@intel.com>
>
> * NEWS: Announce SHF_GNU_RETAIN.
> * config/obj-elf.c (get_section_by_match): Update struct member name.
> (obj_elf_change_section): Warn/error for state change of SHF_GNU_RETAIN.
> (obj_elf_parse_section_letters): Handle 'R' flag.
> Handle numeric flag values within the SHF_MASKOS range.
> (obj_elf_section): Validate SHF_GNU_RETAIN usage.
> * config/obj-elf.h (struct elf_section_match): Adjust "info" member
> name to "sh_info". Add "sh_flags" member.
> * doc/as.texi (Section): Document 'R' flag.
> * testsuite/gas/elf/elf.exp: Run new tests.
> * testsuite/gas/elf/section10.d: Don't test SHF_GNU_RETAIN bit of
> section flag.
> * testsuite/gas/elf/section10.s: Don't set SHF_GNU_RETAIN bit of
> section flag.
> * testsuite/gas/elf/section22.d: New test.
> * testsuite/gas/elf/section22.s: New test.
> * testsuite/gas/elf/section23.s: New test.
> * testsuite/gas/elf/section23a.d: New test.
> * testsuite/gas/elf/section23b.d: New test.
> * testsuite/gas/elf/section23b.err: New test.
> * testsuite/gas/elf/section24.d: New test.
> * testsuite/gas/elf/section24.l: New test.
> * testsuite/gas/elf/section24.s: New test.
>
> include/ChangeLog:
>
> 2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
>
> * elf/common.h (SHF_GNU_RETAIN): Define.
>
> ld/ChangeLog:
>
> 2020-10-09 Jozef Lawrynowicz <jozef.l@mittosystems.com>
>
> * NEWS: Announce SHF_GNU_RETAIN.
> * ld.texi (garbage collection): Document SHF_GNU_RETAIN.
> (Output Section Discarding): Likewise.
> * testsuite/ld-elf/elf.exp: Run new tests.
> * testsuite/ld-elf/retain1.s: New test.
> * testsuite/ld-elf/retain1a.d: New test.
> * testsuite/ld-elf/retain1b.d: New test.
> * testsuite/ld-elf/retain2.d: New test.
> * testsuite/ld-elf/retain2.ld: New test.
> * testsuite/ld-elf/retain2.map: New test.
> * testsuite/ld-elf/retain3.d: New test.
> * testsuite/ld-elf/retain3.s: New test.
> * testsuite/ld-elf/retain4.d: New test.
> * testsuite/ld-elf/retain4.s: New test.
> * testsuite/ld-elf/retain5.d: New test.
> * testsuite/ld-elf/retain5.map: New test.
> * testsuite/ld-elf/retain5lib.s: New test.
> * testsuite/ld-elf/retain5main.s: New test.
> * testsuite/ld-elf/retain6a.d: New test.
> * testsuite/ld-elf/retain6b.d: New test.
> * testsuite/ld-elf/retain6lib.s: New test.
> * testsuite/ld-elf/retain6main.s: New test.
> ---
> bfd/elf-bfd.h | 9 +-
> bfd/elf.c | 17 ++-
> bfd/elflink.c | 4 +-
> binutils/NEWS | 4 +
> binutils/readelf.c | 51 ++++++++-
> .../binutils-all/readelf-maskos-1a.d | 10 ++
> .../binutils-all/readelf-maskos-1b.d | 12 ++
> .../testsuite/binutils-all/readelf-maskos.s | 11 ++
> binutils/testsuite/binutils-all/readelf.exp | 9 +-
> binutils/testsuite/binutils-all/retain1.s | 104 ++++++++++++++++++
> binutils/testsuite/binutils-all/retain1a.d | 18 +++
> binutils/testsuite/binutils-all/retain1b.d | 46 ++++++++
> binutils/testsuite/lib/binutils-common.exp | 5 +-
> gas/NEWS | 5 +
> gas/config/obj-elf.c | 88 +++++++++++----
> gas/config/obj-elf.h | 3 +-
> gas/doc/as.texi | 3 +
> gas/testsuite/gas/elf/elf.exp | 5 +-
> gas/testsuite/gas/elf/section10.d | 4 +-
> gas/testsuite/gas/elf/section10.s | 4 +-
> gas/testsuite/gas/elf/section22.d | 19 ++++
> gas/testsuite/gas/elf/section22.s | 34 ++++++
> gas/testsuite/gas/elf/section23.s | 11 ++
> gas/testsuite/gas/elf/section23a.d | 11 ++
> gas/testsuite/gas/elf/section23b.d | 6 +
> gas/testsuite/gas/elf/section23b.err | 2 +
> gas/testsuite/gas/elf/section24.d | 18 +++
> gas/testsuite/gas/elf/section24.l | 4 +
> gas/testsuite/gas/elf/section24.s | 32 ++++++
> include/elf/common.h | 1 +
> ld/NEWS | 4 +
> ld/ld.texi | 7 ++
> ld/testsuite/ld-elf/elf.exp | 11 ++
> ld/testsuite/ld-elf/retain1.s | 104 ++++++++++++++++++
> ld/testsuite/ld-elf/retain1a.d | 28 +++++
> ld/testsuite/ld-elf/retain1b.d | 11 ++
> ld/testsuite/ld-elf/retain2.d | 6 +
> ld/testsuite/ld-elf/retain2.ld | 7 ++
> ld/testsuite/ld-elf/retain2.map | 32 ++++++
> ld/testsuite/ld-elf/retain3.d | 12 ++
> ld/testsuite/ld-elf/retain3.s | 19 ++++
> ld/testsuite/ld-elf/retain4.d | 10 ++
> ld/testsuite/ld-elf/retain4.s | 13 +++
> ld/testsuite/ld-elf/retain5.d | 12 ++
> ld/testsuite/ld-elf/retain5.map | 5 +
> ld/testsuite/ld-elf/retain5lib.s | 6 +
> ld/testsuite/ld-elf/retain5main.s | 5 +
> ld/testsuite/ld-elf/retain6a.d | 14 +++
> ld/testsuite/ld-elf/retain6b.d | 11 ++
> ld/testsuite/ld-elf/retain6lib.s | 17 +++
> ld/testsuite/ld-elf/retain6main.s | 13 +++
> 51 files changed, 853 insertions(+), 44 deletions(-)
> create mode 100644 binutils/testsuite/binutils-all/readelf-maskos-1a.d
> create mode 100644 binutils/testsuite/binutils-all/readelf-maskos-1b.d
> create mode 100644 binutils/testsuite/binutils-all/readelf-maskos.s
> create mode 100644 binutils/testsuite/binutils-all/retain1.s
> create mode 100644 binutils/testsuite/binutils-all/retain1a.d
> create mode 100644 binutils/testsuite/binutils-all/retain1b.d
> create mode 100644 gas/testsuite/gas/elf/section22.d
> create mode 100644 gas/testsuite/gas/elf/section22.s
> create mode 100644 gas/testsuite/gas/elf/section23.s
> create mode 100644 gas/testsuite/gas/elf/section23a.d
> create mode 100644 gas/testsuite/gas/elf/section23b.d
> create mode 100644 gas/testsuite/gas/elf/section23b.err
> create mode 100644 gas/testsuite/gas/elf/section24.d
> create mode 100644 gas/testsuite/gas/elf/section24.l
> create mode 100644 gas/testsuite/gas/elf/section24.s
> create mode 100644 ld/testsuite/ld-elf/retain1.s
> create mode 100644 ld/testsuite/ld-elf/retain1a.d
> create mode 100644 ld/testsuite/ld-elf/retain1b.d
> create mode 100644 ld/testsuite/ld-elf/retain2.d
> create mode 100644 ld/testsuite/ld-elf/retain2.ld
> create mode 100644 ld/testsuite/ld-elf/retain2.map
> create mode 100644 ld/testsuite/ld-elf/retain3.d
> create mode 100644 ld/testsuite/ld-elf/retain3.s
> create mode 100644 ld/testsuite/ld-elf/retain4.d
> create mode 100644 ld/testsuite/ld-elf/retain4.s
> create mode 100644 ld/testsuite/ld-elf/retain5.d
> create mode 100644 ld/testsuite/ld-elf/retain5.map
> create mode 100644 ld/testsuite/ld-elf/retain5lib.s
> create mode 100644 ld/testsuite/ld-elf/retain5main.s
> create mode 100644 ld/testsuite/ld-elf/retain6a.d
> create mode 100644 ld/testsuite/ld-elf/retain6b.d
> create mode 100644 ld/testsuite/ld-elf/retain6lib.s
> create mode 100644 ld/testsuite/ld-elf/retain6main.s
>
> diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
> index 140a98594d..ffb75f7919 100644
> --- a/bfd/elf-bfd.h
> +++ b/bfd/elf-bfd.h
> @@ -1897,14 +1897,15 @@ struct output_elf_obj_tdata
> bfd_boolean flags_init;
> };
>
> -/* Indicate if the bfd contains SHF_GNU_MBIND sections or symbols that
> - have the STT_GNU_IFUNC symbol type or STB_GNU_UNIQUE binding. Used
> - to set the osabi field in the ELF header structure. */
> +/* Indicate if the bfd contains SHF_GNU_MBIND/SHF_GNU_RETAIN sections or
> + symbols that have the STT_GNU_IFUNC symbol type or STB_GNU_UNIQUE
> + binding. Used to set the osabi field in the ELF header structure. */
> enum elf_gnu_osabi
> {
> elf_gnu_osabi_mbind = 1 << 0,
> elf_gnu_osabi_ifunc = 1 << 1,
> elf_gnu_osabi_unique = 1 << 2,
> + elf_gnu_osabi_retain = 1 << 3,
> };
>
> typedef struct elf_section_list
> @@ -2034,7 +2035,7 @@ struct elf_obj_tdata
> ENUM_BITFIELD (dynamic_lib_link_class) dyn_lib_class : 4;
>
> /* Whether the bfd uses OS specific bits that require ELFOSABI_GNU. */
> - ENUM_BITFIELD (elf_gnu_osabi) has_gnu_osabi : 3;
> + ENUM_BITFIELD (elf_gnu_osabi) has_gnu_osabi : 4;
>
> /* Whether if the bfd contains the GNU_PROPERTY_NO_COPY_ON_PROTECTED
> property. */
> diff --git a/bfd/elf.c b/bfd/elf.c
> index 9d7cbd52e0..dc097e825a 100644
> --- a/bfd/elf.c
> +++ b/bfd/elf.c
> @@ -1066,9 +1066,12 @@ _bfd_elf_make_section_from_shdr (bfd *abfd,
> /* FIXME: We should not recognize SHF_GNU_MBIND for ELFOSABI_NONE,
> but binutils as of 2019-07-23 did not set the EI_OSABI header
> byte. */
> - case ELFOSABI_NONE:
> case ELFOSABI_GNU:
> case ELFOSABI_FREEBSD:
> + if ((hdr->sh_flags & SHF_GNU_RETAIN) != 0)
> + elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_retain;
> + /* Fall through */
> + case ELFOSABI_NONE:
> if ((hdr->sh_flags & SHF_GNU_MBIND) != 0)
> elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_mbind;
> break;
> @@ -12464,11 +12467,17 @@ _bfd_elf_final_write_processing (bfd *abfd)
> && i_ehdrp->e_ident[EI_OSABI] != ELFOSABI_FREEBSD)
> {
> if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_mbind)
> - _bfd_error_handler (_("GNU_MBIND section is unsupported"));
> + _bfd_error_handler (_("GNU_MBIND section is supported only by GNU "
> + "and FreeBSD targets"));
> if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_ifunc)
> - _bfd_error_handler (_("symbol type STT_GNU_IFUNC is unsupported"));
> + _bfd_error_handler (_("symbol type STT_GNU_IFUNC is supported "
> + "only by GNU and FreeBSD targets"));
> if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_unique)
> - _bfd_error_handler (_("symbol binding STB_GNU_UNIQUE is unsupported"));
> + _bfd_error_handler (_("symbol binding STB_GNU_UNIQUE is supported "
> + "only by GNU and FreeBSD targets"));
> + if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_retain)
> + _bfd_error_handler (_("GNU_RETAIN section is supported "
> + "only by GNU and FreeBSD targets"));
> bfd_set_error (bfd_error_sorry);
> return FALSE;
> }
> diff --git a/bfd/elflink.c b/bfd/elflink.c
> index e23d189b98..742254055c 100644
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -14103,7 +14103,9 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
> == SHT_FINI_ARRAY)))
> || (elf_section_data (o)->this_hdr.sh_type == SHT_NOTE
> && elf_next_in_group (o) == NULL
> - && elf_linked_to_section (o) == NULL)))
> + && elf_linked_to_section (o) == NULL)
> + || ((elf_tdata (sub)->has_gnu_osabi & elf_gnu_osabi_retain)
> + && (elf_section_flags (o) & SHF_GNU_RETAIN))))
> {
> if (!_bfd_elf_gc_mark (info, o, gc_mark_hook))
> return FALSE;
> diff --git a/binutils/NEWS b/binutils/NEWS
> index c0dc73d7d8..ceea7731c5 100644
> --- a/binutils/NEWS
> +++ b/binutils/NEWS
> @@ -4,6 +4,10 @@
> symbol names. In addition the --demangle=<style>, --no-demangle,
> --recurse-limit and --no-recurse-limit options are also now availale.
>
> +* Add support for the SHF_GNU_RETAIN ELF section flag.
> + This flag specifies that the section should not be garbage collected by the
> + linker.
> +
> Changes in 2.35:
>
> * Changed readelf's display of symbol names when wide mode is not enabled.
> diff --git a/binutils/readelf.c b/binutils/readelf.c
> index 9ba4e29a65..e6ec99a2cc 100644
> --- a/binutils/readelf.c
> +++ b/binutils/readelf.c
> @@ -5977,6 +5977,8 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
> /* 24 */ { STRING_COMMA_LEN ("GNU_MBIND") },
> /* VLE specific. */
> /* 25 */ { STRING_COMMA_LEN ("VLE") },
> + /* GNU specific. */
> + /* 26 */ { STRING_COMMA_LEN ("GNU_RETAIN") },
> };
>
> if (do_section_details)
> @@ -6009,7 +6011,6 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
> case SHF_TLS: sindex = 9; break;
> case SHF_EXCLUDE: sindex = 18; break;
> case SHF_COMPRESSED: sindex = 20; break;
> - case SHF_GNU_MBIND: sindex = 24; break;
>
> default:
> sindex = -1;
> @@ -6061,10 +6062,26 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
> if (flag == SHF_PPC_VLE)
> sindex = 25;
> break;
> + }
>
> + switch (filedata->file_header.e_ident[EI_OSABI])
> + {
> + case ELFOSABI_GNU:
> + case ELFOSABI_FREEBSD:
> + if (flag == SHF_GNU_RETAIN)
> + sindex = 26;
> + /* Fall through */
> + case ELFOSABI_NONE:
> + if (flag == SHF_GNU_MBIND)
> + /* We should not recognize SHF_GNU_MBIND for
> + ELFOSABI_NONE, but binutils as of 2019-07-23 did
> + not set the EI_OSABI header byte. */
> + sindex = 24;
> + break;
> default:
> break;
> }
> + break;
> }
>
> if (sindex != -1)
> @@ -6107,7 +6124,6 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
> case SHF_TLS: *p = 'T'; break;
> case SHF_EXCLUDE: *p = 'E'; break;
> case SHF_COMPRESSED: *p = 'C'; break;
> - case SHF_GNU_MBIND: *p = 'D'; break;
>
> default:
> if ((filedata->file_header.e_machine == EM_X86_64
> @@ -6117,14 +6133,37 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
> *p = 'l';
> else if (filedata->file_header.e_machine == EM_ARM
> && flag == SHF_ARM_PURECODE)
> - *p = 'y';
> + *p = 'y';
> else if (filedata->file_header.e_machine == EM_PPC
> && flag == SHF_PPC_VLE)
> - *p = 'v';
> + *p = 'v';
> else if (flag & SHF_MASKOS)
> {
> - *p = 'o';
> - sh_flags &= ~ SHF_MASKOS;
> + switch (filedata->file_header.e_ident[EI_OSABI])
> + {
> + case ELFOSABI_GNU:
> + case ELFOSABI_FREEBSD:
> + if (flag == SHF_GNU_RETAIN)
> + {
> + *p = 'R';
> + break;
> + }
> + /* Fall through */
> + case ELFOSABI_NONE:
> + if (flag == SHF_GNU_MBIND)
> + {
> + /* We should not recognize SHF_GNU_MBIND for
> + ELFOSABI_NONE, but binutils as of 2019-07-23 did
> + not set the EI_OSABI header byte. */
> + *p = 'D';
> + break;
> + }
> + /* Fall through */
> + default:
> + *p = 'o';
> + sh_flags &= ~SHF_MASKOS;
> + break;
> + }
> }
> else if (flag & SHF_MASKPROC)
> {
> diff --git a/binutils/testsuite/binutils-all/readelf-maskos-1a.d b/binutils/testsuite/binutils-all/readelf-maskos-1a.d
> new file mode 100644
> index 0000000000..7b27358599
> --- /dev/null
> +++ b/binutils/testsuite/binutils-all/readelf-maskos-1a.d
> @@ -0,0 +1,10 @@
> +#name: Unknown SHF_MASKOS value in section
> +#source: readelf-maskos.s
> +#notarget: [supports_gnu_osabi] msp430-*-elf visium-*-elf
> +#xfail: arm-*-elf
> +#readelf: -S --wide
> +# PR26722 for the arm-*-elf XFAIL
> +
> +#...
> + \[[ 0-9]+\] .data.retain_var.*WAo.*
> +#pass
> diff --git a/binutils/testsuite/binutils-all/readelf-maskos-1b.d b/binutils/testsuite/binutils-all/readelf-maskos-1b.d
> new file mode 100644
> index 0000000000..2cbb58a73b
> --- /dev/null
> +++ b/binutils/testsuite/binutils-all/readelf-maskos-1b.d
> @@ -0,0 +1,12 @@
> +#name: -t (section details) for unknown SHF_MASKOS value in section
> +#source: readelf-maskos.s
> +#notarget: [supports_gnu_osabi] msp430-*-elf visium-*-elf
> +#xfail: arm-*-elf
> +#readelf: -S -t --wide
> +# PR26722 for the arm-*-elf XFAIL
> +
> +#...
> + \[[ 0-9]+\] .data.retain_var
> + PROGBITS +0+ +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +0 +0 +(1|2|4|8)
> + \[00200003\]: WRITE, ALLOC, OS \(00200000\)
> +#pass
> diff --git a/binutils/testsuite/binutils-all/readelf-maskos.s b/binutils/testsuite/binutils-all/readelf-maskos.s
> new file mode 100644
> index 0000000000..d671119bca
> --- /dev/null
> +++ b/binutils/testsuite/binutils-all/readelf-maskos.s
> @@ -0,0 +1,11 @@
> + .section .data.retain_var,"0x200003"
> + .global retain_var
> + .type retain_var, %object
> +retain_var:
> + .long 2
> +
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> diff --git a/binutils/testsuite/binutils-all/readelf.exp b/binutils/testsuite/binutils-all/readelf.exp
> index 1fb36ae5c4..9d1d496e5c 100644
> --- a/binutils/testsuite/binutils-all/readelf.exp
> +++ b/binutils/testsuite/binutils-all/readelf.exp
> @@ -364,8 +364,15 @@ readelf_wi_test
> readelf_compressed_wa_test
>
> readelf_dump_test
> -run_dump_test "pr25543"
>
> +# These dump tests require an assembler.
> +if {[which $AS] != 0} then {
> + run_dump_test "pr25543"
> + run_dump_test "retain1a"
> + run_dump_test "retain1b"
> + run_dump_test "readelf-maskos-1a"
> + run_dump_test "readelf-maskos-1b"
> +}
>
> # PR 13482 - Check for off-by-one errors when dumping .note sections.
> if {![binutils_assemble $srcdir/$subdir/version.s tmpdir/version.o]} then {
> diff --git a/binutils/testsuite/binutils-all/retain1.s b/binutils/testsuite/binutils-all/retain1.s
> new file mode 100644
> index 0000000000..f7716faabe
> --- /dev/null
> +++ b/binutils/testsuite/binutils-all/retain1.s
> @@ -0,0 +1,104 @@
> + .global discard0
> + .section .bss.discard0,"aw"
> + .type discard0, %object
> +discard0:
> + .zero 2
> +
> + .global discard1
> + .section .bss.discard1,"aw"
> + .type discard1, %object
> +discard1:
> + .zero 2
> +
> + .global discard2
> + .section .data.discard2,"aw"
> + .type discard2, %object
> +discard2:
> + .word 1
> +
> + .section .bss.sdiscard0,"aw"
> + .type sdiscard0, %object
> +sdiscard0:
> + .zero 2
> +
> + .section .bss.sdiscard1,"aw"
> + .type sdiscard1, %object
> +sdiscard1:
> + .zero 2
> +
> + .section .data.sdiscard2,"aw"
> + .type sdiscard2, %object
> +sdiscard2:
> + .word 1
> +
> + .section .text.fndiscard0,"ax"
> + .global fndiscard0
> + .type fndiscard0, %function
> +fndiscard0:
> + .word 0
> +
> + .global retain0
> + .section .bss.retain0,"awR"
> + .type retain0, %object
> +retain0:
> + .zero 2
> +
> + .global retain1
> + .section .bss.retain1,"awR"
> + .type retain1, %object
> +retain1:
> + .zero 2
> +
> + .global retain2
> + .section .data.retain2,"awR"
> + .type retain2, %object
> +retain2:
> + .word 1
> +
> + .section .bss.sretain0,"awR"
> + .type sretain0, %object
> +sretain0:
> + .zero 2
> +
> + .section .bss.sretain1,"awR"
> + .type sretain1, %object
> +sretain1:
> + .zero 2
> +
> + .section .data.sretain2,"aRw"
> + .type sretain2, %object
> +sretain2:
> + .word 1
> +
> + .section .text.fnretain1,"Rax"
> + .global fnretain1
> + .type fnretain1, %function
> +fnretain1:
> + .word 0
> +
> + .section .text.fndiscard2,"ax"
> + .global fndiscard2
> + .type fndiscard2, %function
> +fndiscard2:
> + .word 0
> +
> + .section .bss.lsretain0,"awR"
> + .type lsretain0.2, %object
> +lsretain0.2:
> + .zero 2
> +
> + .section .bss.lsretain1,"aRw"
> + .type lsretain1.1, %object
> +lsretain1.1:
> + .zero 2
> +
> + .section .data.lsretain2,"aRw"
> + .type lsretain2.0, %object
> +lsretain2.0:
> + .word 1
> +
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> diff --git a/binutils/testsuite/binutils-all/retain1a.d b/binutils/testsuite/binutils-all/retain1a.d
> new file mode 100644
> index 0000000000..6397ac52ae
> --- /dev/null
> +++ b/binutils/testsuite/binutils-all/retain1a.d
> @@ -0,0 +1,18 @@
> +#name: readelf SHF_GNU_RETAIN
> +#source: retain1.s
> +#target: [supports_gnu_osabi]
> +#readelf: -S --wide
> +
> +#...
> + \[[ 0-9]+\] .bss.retain0.*WAR.*
> + \[[ 0-9]+\] .bss.retain1.*WAR.*
> + \[[ 0-9]+\] .data.retain2.*WAR.*
> + \[[ 0-9]+\] .bss.sretain0.*WAR.*
> + \[[ 0-9]+\] .bss.sretain1.*WAR.*
> + \[[ 0-9]+\] .data.sretain2.*WAR.*
> + \[[ 0-9]+\] .text.fnretain1.*AXR.*
> +#...
> + \[[ 0-9]+\] .bss.lsretain0.*WAR.*
> + \[[ 0-9]+\] .bss.lsretain1.*WAR.*
> + \[[ 0-9]+\] .data.lsretain2.*WAR.*
> +#pass
> diff --git a/binutils/testsuite/binutils-all/retain1b.d b/binutils/testsuite/binutils-all/retain1b.d
> new file mode 100644
> index 0000000000..12bc388ba1
> --- /dev/null
> +++ b/binutils/testsuite/binutils-all/retain1b.d
> @@ -0,0 +1,46 @@
> +#name: -t (section details) for readelf SHF_GNU_RETAIN
> +#source: retain1.s
> +#target: [supports_gnu_osabi]
> +#readelf: -S -t --wide
> +
> +#...
> + \[[ 0-9]+\] .bss.retain0
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .bss.retain1
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .data.retain2
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .bss.sretain0
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .bss.sretain1
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .data.sretain2
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .text.fnretain1
> +#...
> + \[0+200006\]: ALLOC, EXEC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .bss.lsretain0
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .bss.lsretain1
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#...
> + \[[ 0-9]+\] .data.lsretain2
> +#...
> + \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
> +#pass
> diff --git a/binutils/testsuite/lib/binutils-common.exp b/binutils/testsuite/lib/binutils-common.exp
> index b9a1e6e4bc..a43639bafb 100644
> --- a/binutils/testsuite/lib/binutils-common.exp
> +++ b/binutils/testsuite/lib/binutils-common.exp
> @@ -195,13 +195,15 @@ proc match_target { target } {
>
> # True if the ELF target supports setting the ELF header OSABI field
> # to ELFOSABI_GNU or ELFOSABI_FREEBSD, a requirement for STT_GNU_IFUNC
> -# symbol and SHF_GNU_MBIND section support.
> +# symbol and SHF_GNU_MBIND or SHF_GNU_RETAIN section support.
> #
> # This generally depends on the target OS only, however there are a
> # number of exceptions for bare metal targets as follows. The MSP430
> # and Visium targets set OSABI to ELFOSABI_STANDALONE. Likewise
> # non-EABI ARM targets set OSABI to ELFOSABI_ARM
> #
> +# Non-Linux HPPA defaults to ELFOSABI_HPUX.
> +#
> # Note that some TI C6X targets use ELFOSABI_C6000_* but one doesn't,
> # so we don't try to sort out tic6x here. (The effect is that linker
> # testcases will generally need to exclude tic6x or use a -m option.)
> @@ -227,6 +229,7 @@ proc supports_gnu_osabi {} {
> }
> if { [istarget "arm*-*-*"]
> || [istarget "msp430-*-*"]
> + || [istarget "hppa-unknown-elf"]
> || [istarget "visium-*-*"] } {
> return 0
> }
> diff --git a/gas/NEWS b/gas/NEWS
> index 1107725ea6..33005b5904 100644
> --- a/gas/NEWS
> +++ b/gas/NEWS
> @@ -30,6 +30,11 @@
>
> * Configure with --enable-x86-used-note by default for Linux/x86.
>
> +* Add support for the "R" flag in the .section directive.
> + This flag requires ELFOSABI_GNU or ELFOSABI_FREEBSD, and applies the
> + ELF SHF_GNU_RETAIN flag to the specified section. This flag specifies
> + the section should not be garbage collected by the linker.
> +
> Changes in 2.35:
>
> * X86 NaCl target support is removed.
> diff --git a/gas/config/obj-elf.c b/gas/config/obj-elf.c
> index f061ea61f3..6586478975 100644
> --- a/gas/config/obj-elf.c
> +++ b/gas/config/obj-elf.c
> @@ -529,9 +529,9 @@ get_section_by_match (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *inf)
> const char *group_name = elf_group_name (sec);
> const char *linked_to_symbol_name
> = sec->map_head.linked_to_symbol_name;
> - unsigned int info = elf_section_data (sec)->this_hdr.sh_info;
> + unsigned int sh_info = elf_section_data (sec)->this_hdr.sh_info;
>
> - return (info == match->info
> + return (sh_info == match->sh_info
> && ((bfd_section_flags (sec) & SEC_ASSEMBLER_SECTION_ID)
> == (match->flags & SEC_ASSEMBLER_SECTION_ID))
> && sec->section_id == match->section_id
> @@ -740,7 +740,7 @@ obj_elf_change_section (const char *name,
> type = bfd_elf_get_default_section_type (flags);
> elf_section_type (sec) = type;
> elf_section_flags (sec) = attr;
> - elf_section_data (sec)->this_hdr.sh_info = match_p->info;
> + elf_section_data (sec)->this_hdr.sh_info = match_p->sh_info;
>
> /* Prevent SEC_HAS_CONTENTS from being inadvertently set. */
> if (type == SHT_NOBITS)
> @@ -798,7 +798,10 @@ obj_elf_change_section (const char *name,
> & (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
> | SEC_EXCLUDE | SEC_SORT_ENTRIES | SEC_MERGE | SEC_STRINGS
> | SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD
> - | SEC_THREAD_LOCAL)))
> + | SEC_THREAD_LOCAL))
> + || ((elf_tdata (stdoutput)->has_gnu_osabi & elf_gnu_osabi_retain)
> + && ((elf_section_flags (old_sec) ^ match_p->sh_flags)
> + & SHF_GNU_RETAIN)))
> {
> if (ssect != NULL)
> as_warn (_("ignoring changed section attributes for %s"), name);
> @@ -861,6 +864,9 @@ obj_elf_parse_section_letters (char *str, size_t len,
> case 'd':
> *gnu_attr |= SHF_GNU_MBIND;
> break;
> + case 'R':
> + *gnu_attr |= SHF_GNU_RETAIN;
> + break;
> case '?':
> *is_clone = TRUE;
> break;
> @@ -890,8 +896,32 @@ obj_elf_parse_section_letters (char *str, size_t len,
> if (ISDIGIT (*str))
> {
> char * end;
> + struct elf_backend_data *bed;
> + bfd_vma numeric_flags = strtoul (str, &end, 0);
> +
> + attr |= numeric_flags;
> +
> + bed = (struct elf_backend_data *)
> + get_elf_backend_data (stdoutput);
> +
> + if (bed->elf_osabi == ELFOSABI_NONE
> + || bed->elf_osabi == ELFOSABI_STANDALONE
> + || bed->elf_osabi == ELFOSABI_GNU
> + || bed->elf_osabi == ELFOSABI_FREEBSD)
> + {
> + /* Add flags in the SHF_MASKOS range to gnu_attr for
> + OSABIs that support those flags.
> + Also adding the flags for ELFOSABI_{NONE,STANDALONE}
> + allows them to be validated later in obj_elf_section.
> + We can't just always set these bits in gnu_attr for
> + all OSABIs, since Binutils does not recognize all
> + SHF_MASKOS bits for non-GNU OSABIs. It's therefore
> + possible that numeric flags are being used to set bits
> + in the SHF_MASKOS range for those targets, and we
> + don't want assembly to fail in those situations. */
> + *gnu_attr |= (numeric_flags & SHF_MASKOS);
> + }
>
> - attr |= strtoul (str, & end, 0);
> /* Update str and len, allowing for the fact that
> we will execute str++ and len-- below. */
> end --;
> @@ -1287,18 +1317,21 @@ obj_elf_section (int push)
> if (ISDIGIT (* input_line_pointer))
> {
> char *t = input_line_pointer;
> - match.info = strtoul (input_line_pointer,
> + match.sh_info = strtoul (input_line_pointer,
> &input_line_pointer, 0);
> - if (match.info == (unsigned int) -1)
> + if (match.sh_info == (unsigned int) -1)
> {
> as_warn (_("unsupported mbind section info: %s"), t);
> - match.info = 0;
> + match.sh_info = 0;
> }
> }
> else
> input_line_pointer = save;
> }
>
> + if ((gnu_attr & SHF_GNU_RETAIN) != 0)
> + match.sh_flags |= SHF_GNU_RETAIN;
> +
> if (*input_line_pointer == ',')
> {
> char *save = input_line_pointer;
> @@ -1387,26 +1420,39 @@ obj_elf_section (int push)
> done:
> demand_empty_rest_of_line ();
>
> - obj_elf_change_section (name, type, attr, entsize, &match, linkonce,
> - push);
> -
> - if ((gnu_attr & SHF_GNU_MBIND) != 0)
> + if ((gnu_attr & (SHF_GNU_MBIND | SHF_GNU_RETAIN)) != 0)
> {
> struct elf_backend_data *bed;
> + bfd_boolean mbind_p = (gnu_attr & SHF_GNU_MBIND) != 0;
>
> - if ((attr & SHF_ALLOC) == 0)
> + if (mbind_p && (attr & SHF_ALLOC) == 0)
> as_bad (_("SHF_ALLOC isn't set for GNU_MBIND section: %s"), name);
>
> bed = (struct elf_backend_data *) get_elf_backend_data (stdoutput);
> - if (bed->elf_osabi == ELFOSABI_NONE)
> - bed->elf_osabi = ELFOSABI_GNU;
> - else if (bed->elf_osabi != ELFOSABI_GNU
> - && bed->elf_osabi != ELFOSABI_FREEBSD)
> - as_bad (_("GNU_MBIND section is supported only by GNU "
> - "and FreeBSD targets"));
> - elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_mbind;
> +
> + if (bed->elf_osabi != ELFOSABI_GNU
> + && bed->elf_osabi != ELFOSABI_FREEBSD
> + && bed->elf_osabi != ELFOSABI_NONE)
> + {
> + as_bad (_("%s section is supported only by GNU and FreeBSD targets"),
> + mbind_p ? "GNU_MBIND" : "GNU_RETAIN");
> + }
> + else
> + {
> + if (bed->elf_osabi == ELFOSABI_NONE)
> + bed->elf_osabi = ELFOSABI_GNU;
> +
> + if (mbind_p)
> + elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_mbind;
> + if ((gnu_attr & SHF_GNU_RETAIN) != 0)
> + elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_retain;
> +
> + attr |= gnu_attr;
> + }
> }
> - elf_section_flags (now_seg) |= gnu_attr;
> +
> + obj_elf_change_section (name, type, attr, entsize, &match, linkonce,
> + push);
>
> if (linked_to_section_index != -1UL)
> {
> diff --git a/gas/config/obj-elf.h b/gas/config/obj-elf.h
> index 4f29572eef..0a91ed462f 100644
> --- a/gas/config/obj-elf.h
> +++ b/gas/config/obj-elf.h
> @@ -106,8 +106,9 @@ struct elf_section_match
> {
> const char * group_name;
> const char * linked_to_symbol_name;
> - unsigned int info;
> unsigned int section_id;
> + unsigned int sh_info; /* ELF section information. */
> + bfd_vma sh_flags; /* ELF section flags. */
> flagword flags;
> };
>
> diff --git a/gas/doc/as.texi b/gas/doc/as.texi
> index 4d5294552a..e92432a8bd 100644
> --- a/gas/doc/as.texi
> +++ b/gas/doc/as.texi
> @@ -6657,6 +6657,9 @@ section is a member of a section group
> section is used for thread-local-storage
> @item ?
> section is a member of the previously-current section's group, if any
> +@item R
> +retained section (apply SHF_GNU_RETAIN to prevent linker garbage
> +collection, GNU ELF extension)
> @item @code{<number>}
> a numeric value indicating the bits to be set in the ELF section header's flags
> field. Note - if one or more of the alphabetic characters described above is
> diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
> index 9d75154483..49d5a47959 100644
> --- a/gas/testsuite/gas/elf/elf.exp
> +++ b/gas/testsuite/gas/elf/elf.exp
> @@ -261,8 +261,11 @@ if { [is_elf_format] } then {
> run_dump_test "section19"
> run_dump_test "section20"
> run_dump_test "section21"
> + run_dump_test "section22"
> + run_dump_test "section23a"
> + run_dump_test "section23b"
> + run_dump_test "section24"
> run_dump_test "sh-link-zero"
> -
> run_dump_test "dwarf2-1" $dump_opts
> run_dump_test "dwarf2-2" $dump_opts
> run_dump_test "dwarf2-3" $dump_opts
> diff --git a/gas/testsuite/gas/elf/section10.d b/gas/testsuite/gas/elf/section10.d
> index 554a791f1d..6aa7b088b1 100644
> --- a/gas/testsuite/gas/elf/section10.d
> +++ b/gas/testsuite/gas/elf/section10.d
> @@ -18,7 +18,7 @@
> #...
> [ ]*\[.*\][ ]+sec3
> [ ]*PROGBITS.*
> -[ ]*\[.*fefff030\]: MERGE, STRINGS,.* EXCLUDE, OS \(.*ef00000\), PROC \(.*[3467]0000000\), UNKNOWN \(0+0ff000\)
> +[ ]*\[.*fedff030\]: MERGE, STRINGS,.* EXCLUDE, OS \(.*ed00000\), PROC \(.*[3467]0000000\), UNKNOWN \(0+0ff000\)
> #...
> [ ]*\[.*\][ ]+sec4
> [ ]*LOOS\+0x11[ ].*
> @@ -26,7 +26,7 @@
> #...
> [ ]*\[.*\][ ]+sec5
> [ ]*LOUSER\+0x9[ ].*
> -[ ]*\[.*feff0000\]:.* EXCLUDE, OS \(.*ef00000\), PROC \(.*[3467]0000000\), UNKNOWN \(.*f0000\)
> +[ ]*\[.*fedf0000\]:.* EXCLUDE, OS \(.*ed00000\), PROC \(.*[3467]0000000\), UNKNOWN \(.*f0000\)
> [ ]*\[.*\][ ]+.data.foo
> [ ]*LOUSER\+0x7f000000[ ].*
> [ ]*\[0+003\]: WRITE, ALLOC
> diff --git a/gas/testsuite/gas/elf/section10.s b/gas/testsuite/gas/elf/section10.s
> index 29f1184523..d52b3458fb 100644
> --- a/gas/testsuite/gas/elf/section10.s
> +++ b/gas/testsuite/gas/elf/section10.s
> @@ -7,7 +7,7 @@
> .word 2
>
> # Make sure that specifying further arguments to .sections is still supported
> - .section sec3, "0xfefff000MS", %progbits, 32
> + .section sec3, "0xfedff000MS", %progbits, 32
> .word 3
>
> # Make sure that extra flags can be set for well known sections as well.
> @@ -19,7 +19,7 @@
> .word 5
>
> # Test both together, with a quoted type value.
> - .section sec5, "0xfeff0000", "0x80000009"
> + .section sec5, "0xfedf0000", "0x80000009"
> .word 6
>
> # Test that declaring an extended version of a known special section works.
> diff --git a/gas/testsuite/gas/elf/section22.d b/gas/testsuite/gas/elf/section22.d
> new file mode 100644
> index 0000000000..8aa7fcfc34
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section22.d
> @@ -0,0 +1,19 @@
> +#readelf: -h -S --wide
> +#name: SHF_GNU_RETAIN sections 22
> +#notarget: ![supports_gnu_osabi]
> +
> +#...
> + +OS/ABI: +UNIX - GNU
> +#...
> + \[..\] .text.discard0[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX.*
> +#...
> + \[..\] .data.discard1[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA.*
> +#...
> + \[..\] .bss.discard2[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA.*
> +#...
> + \[..\] .bss.retain0[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
> +#...
> + \[..\] .data.retain1[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
> +#...
> + \[..\] .text.retain2[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR.*
> +#pass
> diff --git a/gas/testsuite/gas/elf/section22.s b/gas/testsuite/gas/elf/section22.s
> new file mode 100644
> index 0000000000..66ed990e57
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section22.s
> @@ -0,0 +1,34 @@
> + .section .text.discard0,"ax",%progbits
> + .global discard0
> + .type discard0, %function
> +discard0:
> + .word 0
> +
> + .section .data.discard1,"aw"
> + .global discard1
> + .type discard1, %object
> +discard1:
> + .word 1
> +
> + .section .bss.discard2,"aw"
> + .global discard2
> + .type discard2, %object
> +discard2:
> + .zero 2
> +
> + .section .bss.retain0,"awR",%nobits
> + .global retain0
> + .type retain0, %object
> +retain0:
> + .zero 2
> +
> + .section .data.retain1,"awR",%progbits
> + .type retain1, %object
> +retain1:
> + .word 1
> +
> + .section .text.retain2,"axR",%progbits
> + .global retain2
> + .type retain2, %function
> +retain2:
> + .word 0
> diff --git a/gas/testsuite/gas/elf/section23.s b/gas/testsuite/gas/elf/section23.s
> new file mode 100644
> index 0000000000..d671119bca
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section23.s
> @@ -0,0 +1,11 @@
> + .section .data.retain_var,"0x200003"
> + .global retain_var
> + .type retain_var, %object
> +retain_var:
> + .long 2
> +
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> diff --git a/gas/testsuite/gas/elf/section23a.d b/gas/testsuite/gas/elf/section23a.d
> new file mode 100644
> index 0000000000..1d850d9e8e
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section23a.d
> @@ -0,0 +1,11 @@
> +#name: SHF_GNU_RETAIN set with numeric flag value in .section
> +#source: section23.s
> +#target: [supports_gnu_osabi]
> +#readelf: -h -S --wide
> +
> +#...
> + +OS/ABI: +UNIX - GNU
> +#...
> + \[..\] .data.retain_var[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
> +#pass
> +
> diff --git a/gas/testsuite/gas/elf/section23b.d b/gas/testsuite/gas/elf/section23b.d
> new file mode 100644
> index 0000000000..c85200e5ff
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section23b.d
> @@ -0,0 +1,6 @@
> +#name: SHF_GNU_RETAIN set with numeric flag value in .section for non-GNU OSABI target
> +#source: section23.s
> +#error_output: section23b.err
> +#target: msp430-*-elf visium-*-elf
> +
> +# This test only runs for targets which set ELFOSABI_STANDALONE.
> diff --git a/gas/testsuite/gas/elf/section23b.err b/gas/testsuite/gas/elf/section23b.err
> new file mode 100644
> index 0000000000..83de60c397
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section23b.err
> @@ -0,0 +1,2 @@
> +.*: Assembler messages:
> +.*:1: Error: GNU_RETAIN section is supported only by GNU and FreeBSD targets
> diff --git a/gas/testsuite/gas/elf/section24.d b/gas/testsuite/gas/elf/section24.d
> new file mode 100644
> index 0000000000..5ee4aee3af
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section24.d
> @@ -0,0 +1,18 @@
> +#name: Warn for SHF_GNU_RETAIN set on existing section
> +#notarget: ![supports_gnu_osabi] rx-*-*
> +#readelf: -h -S --wide
> +#warning_output: section24.l
> +# rx-*-* does not automatically create a ".text" section when starting assembly.
> +
> +#...
> + +OS/ABI: +UNIX - GNU
> +#...
> + \[..\] .text[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX .*
> +#...
> + \[..\] .text[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR .*
> +#...
> + \[..\] .text.foo[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR .*
> +#...
> + \[..\] .text.bar[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX .*
> +#pass
> +
> diff --git a/gas/testsuite/gas/elf/section24.l b/gas/testsuite/gas/elf/section24.l
> new file mode 100644
> index 0000000000..e0ea36078c
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section24.l
> @@ -0,0 +1,4 @@
> +[^:]*: Assembler messages:
> +[^:]*:4: Warning: ignoring changed section attributes for .text
> +[^:]*:20: Warning: ignoring changed section attributes for .text.foo
> +[^:]*:30: Warning: ignoring changed section attributes for .text.bar
> diff --git a/gas/testsuite/gas/elf/section24.s b/gas/testsuite/gas/elf/section24.s
> new file mode 100644
> index 0000000000..deaff0a323
> --- /dev/null
> +++ b/gas/testsuite/gas/elf/section24.s
> @@ -0,0 +1,32 @@
> +/* The default .text section automatically created by the assembler does not
> + have the SHF_GNU_RETAIN flag set, so the "R" flag cannot be used with that,
> + or any other, default section. */
> + .section .text,"axR",%progbits
> +retain_bad:
> + .word 0
> +
> +/* A unique .text section with SHF_GNU_RETAIN applied can be created. */
> + .section .text,"axR",%progbits,unique,0
> +retain_good:
> + .word 0
> +
> +/* SHF_GNU_RETAIN can be applied to a new section. */
> + .section .text.foo,"axR",%progbits
> +foo_retain:
> + .word 0
> +
> +/* If the section is used again without SHF_GNU_RETAIN, a warning should be
> + emitted. */
> + .section .text.foo,"ax",%progbits
> +foo:
> + .word 0
> +
> + .section .text.bar,"ax",%progbits
> +bar:
> + .word 0
> +
> +/* SHF_GNU_RETAIN cannot be applied to a section which was already explicitly
> + declared without SHF_GNU_RETAIN set. */
> + .section .text.bar,"axR",%progbits
> +bar_retain:
> + .word 0
> diff --git a/include/elf/common.h b/include/elf/common.h
> index 571e21af29..c01e562c78 100644
> --- a/include/elf/common.h
> +++ b/include/elf/common.h
> @@ -554,6 +554,7 @@
> /* #define SHF_MASKOS 0x0F000000 *//* OS-specific semantics */
> #define SHF_MASKOS 0x0FF00000 /* New value, Oct 4, 1999 Draft */
> #define SHF_GNU_BUILD_NOTE (1 << 20) /* Section contains GNU BUILD ATTRIBUTE notes. */
> +#define SHF_GNU_RETAIN (1 << 21) /* Section should not be garbage collected by the linker. */
> #define SHF_MASKPROC 0xF0000000 /* Processor-specific semantics */
>
> /* This used to be implemented as a processor specific section flag.
> diff --git a/ld/NEWS b/ld/NEWS
> index e4ae43b257..c103bcebc4 100644
> --- a/ld/NEWS
> +++ b/ld/NEWS
> @@ -15,6 +15,10 @@
> unless you are working on a project that has its own analogue
> of symbol tables that are not reflected in the ELF symtabs.
>
> +* Add support for the SHF_GNU_RETAIN ELF section flag.
> + This flag specifies that the section should not be garbage collected by the
> + linker.
> +
> Changes in 2.35:
>
> * X86 NaCl target support is removed.
> diff --git a/ld/ld.texi b/ld/ld.texi
> index ee592df6c2..849006f0fb 100644
> --- a/ld/ld.texi
> +++ b/ld/ld.texi
> @@ -1787,6 +1787,9 @@ specified either by one of the options @samp{--entry},
> @samp{--undefined}, or @samp{--gc-keep-exported} or by a @code{ENTRY}
> command in the linker script.
>
> +As a GNU extension, ELF input sections marked with the
> +@code{SHF_GNU_RETAIN} flag will not be garbage collected.
> +
> @kindex --print-gc-sections
> @kindex --no-print-gc-sections
> @cindex garbage collection
> @@ -5232,6 +5235,10 @@ The special output section name @samp{/DISCARD/} may be used to discard
> input sections. Any input sections which are assigned to an output
> section named @samp{/DISCARD/} are not included in the output file.
>
> +This can be used to discard input sections marked with the ELF flag
> +@code{SHF_GNU_RETAIN}, which would otherwise have been saved from linker
> +garbage collection.
> +
> Note, sections that match the @samp{/DISCARD/} output section will be
> discarded even if they are in an ELF section group which has other
> members which are not being discarded. This is deliberate.
> diff --git a/ld/testsuite/ld-elf/elf.exp b/ld/testsuite/ld-elf/elf.exp
> index f2ff0397c7..bd06ab0d39 100644
> --- a/ld/testsuite/ld-elf/elf.exp
> +++ b/ld/testsuite/ld-elf/elf.exp
> @@ -119,6 +119,17 @@ if { [istarget "i?86-*-*"] || [istarget "x86_64-*-*"] } {
> set ASFLAGS "$ASFLAGS -mx86-used-note=no"
> }
>
> +# Build libraries required for SHF_GNU_RETAIN tests.
> +if { [check_gc_sections_available] && [supports_gnu_osabi] } {
> + run_ld_link_tests [list \
> + [list "Build libretain5.a" "" "" "" \
> + {retain5lib.s} {} "libretain5.a"] \
> + [list "Build libretain6.a" "" "" "" \
> + {retain6lib.s} {} "libretain6.a"] \
> + ]
> +}
> +
> +
> set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
> foreach t $test_list {
> # We need to strip the ".d", but can leave the dirname.
> diff --git a/ld/testsuite/ld-elf/retain1.s b/ld/testsuite/ld-elf/retain1.s
> new file mode 100644
> index 0000000000..f7716faabe
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain1.s
> @@ -0,0 +1,104 @@
> + .global discard0
> + .section .bss.discard0,"aw"
> + .type discard0, %object
> +discard0:
> + .zero 2
> +
> + .global discard1
> + .section .bss.discard1,"aw"
> + .type discard1, %object
> +discard1:
> + .zero 2
> +
> + .global discard2
> + .section .data.discard2,"aw"
> + .type discard2, %object
> +discard2:
> + .word 1
> +
> + .section .bss.sdiscard0,"aw"
> + .type sdiscard0, %object
> +sdiscard0:
> + .zero 2
> +
> + .section .bss.sdiscard1,"aw"
> + .type sdiscard1, %object
> +sdiscard1:
> + .zero 2
> +
> + .section .data.sdiscard2,"aw"
> + .type sdiscard2, %object
> +sdiscard2:
> + .word 1
> +
> + .section .text.fndiscard0,"ax"
> + .global fndiscard0
> + .type fndiscard0, %function
> +fndiscard0:
> + .word 0
> +
> + .global retain0
> + .section .bss.retain0,"awR"
> + .type retain0, %object
> +retain0:
> + .zero 2
> +
> + .global retain1
> + .section .bss.retain1,"awR"
> + .type retain1, %object
> +retain1:
> + .zero 2
> +
> + .global retain2
> + .section .data.retain2,"awR"
> + .type retain2, %object
> +retain2:
> + .word 1
> +
> + .section .bss.sretain0,"awR"
> + .type sretain0, %object
> +sretain0:
> + .zero 2
> +
> + .section .bss.sretain1,"awR"
> + .type sretain1, %object
> +sretain1:
> + .zero 2
> +
> + .section .data.sretain2,"aRw"
> + .type sretain2, %object
> +sretain2:
> + .word 1
> +
> + .section .text.fnretain1,"Rax"
> + .global fnretain1
> + .type fnretain1, %function
> +fnretain1:
> + .word 0
> +
> + .section .text.fndiscard2,"ax"
> + .global fndiscard2
> + .type fndiscard2, %function
> +fndiscard2:
> + .word 0
> +
> + .section .bss.lsretain0,"awR"
> + .type lsretain0.2, %object
> +lsretain0.2:
> + .zero 2
> +
> + .section .bss.lsretain1,"aRw"
> + .type lsretain1.1, %object
> +lsretain1.1:
> + .zero 2
> +
> + .section .data.lsretain2,"aRw"
> + .type lsretain2.0, %object
> +lsretain2.0:
> + .word 1
> +
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> diff --git a/ld/testsuite/ld-elf/retain1a.d b/ld/testsuite/ld-elf/retain1a.d
> new file mode 100644
> index 0000000000..75abb9856c
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain1a.d
> @@ -0,0 +1,28 @@
> +#name: SHF_GNU_RETAIN 1a
> +#source: retain1.s
> +#ld: -e _start --gc-sections
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> +#DUMPPROG: nm
> +
> +#...
> +[0-9a-f]+ . fnretain1
> +#...
> +[0-9a-f]+ . lsretain0.2
> +#...
> +[0-9a-f]+ . lsretain1.1
> +#...
> +[0-9a-f]+ . lsretain2.0
> +#...
> +[0-9a-f]+ . retain0
> +#...
> +[0-9a-f]+ . retain1
> +#...
> +[0-9a-f]+ . retain2
> +#...
> +[0-9a-f]+ . sretain0
> +#...
> +[0-9a-f]+ . sretain1
> +#...
> +[0-9a-f]+ . sretain2
> +#pass
> diff --git a/ld/testsuite/ld-elf/retain1b.d b/ld/testsuite/ld-elf/retain1b.d
> new file mode 100644
> index 0000000000..815c0150f5
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain1b.d
> @@ -0,0 +1,11 @@
> +#name: SHF_GNU_RETAIN 1b
> +#source: retain1.s
> +#ld: -e _start --gc-sections
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> +#nm: -n
> +
> +#failif
> +#...
> +[0-9a-f]+ . .*discard.*
> +#...
> diff --git a/ld/testsuite/ld-elf/retain2.d b/ld/testsuite/ld-elf/retain2.d
> new file mode 100644
> index 0000000000..11efd6ddb8
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain2.d
> @@ -0,0 +1,6 @@
> +#name: SHF_GNU_RETAIN 2 (remove SHF_GNU_RETAIN sections by placing in /DISCARD/)
> +#source: retain1.s
> +#ld: -e _start -Map=retain2.map --gc-sections --script=retain2.ld
> +#map: retain2.map
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> diff --git a/ld/testsuite/ld-elf/retain2.ld b/ld/testsuite/ld-elf/retain2.ld
> new file mode 100644
> index 0000000000..8ef982753c
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain2.ld
> @@ -0,0 +1,7 @@
> +SECTIONS
> +{
> + /DISCARD/ :
> + {
> + *(.text.fnretain1)
> + }
> +}
> diff --git a/ld/testsuite/ld-elf/retain2.map b/ld/testsuite/ld-elf/retain2.map
> new file mode 100644
> index 0000000000..4028aa1f58
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain2.map
> @@ -0,0 +1,32 @@
> +# Test that .text.fnretain1, which has the SHF_GNU_RETAIN flag, can still be
> +# explicitly discarded from the output file.
> +
> +#...
> +Discarded input sections
> +
> + .text.*
> +#...
> + .data.*
> +#...
> + .bss.*
> +#...
> + .bss.discard0.*
> +#...
> + .bss.discard1.*
> +#...
> + .data.discard2.*
> +#...
> + .bss.sdiscard0.*
> +#...
> + .bss.sdiscard1.*
> +#...
> + .data.sdiscard2.*
> +#...
> + .text.fndiscard0.*
> +#...
> + .text.fnretain1.*
> +#...
> + .text.fndiscard2.*
> +#...
> +Memory Configuration
> +#pass
> diff --git a/ld/testsuite/ld-elf/retain3.d b/ld/testsuite/ld-elf/retain3.d
> new file mode 100644
> index 0000000000..911f5b7594
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain3.d
> @@ -0,0 +1,12 @@
> +#name: SHF_GNU_RETAIN 3 (keep sections referenced by retained sections)
> +#source: retain3.s
> +#ld: -e _start --gc-sections
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> +#DUMPPROG: nm
> +
> +#...
> +[0-9a-f]+ . bar
> +#...
> +[0-9a-f]+ . foo
> +#pass
> diff --git a/ld/testsuite/ld-elf/retain3.s b/ld/testsuite/ld-elf/retain3.s
> new file mode 100644
> index 0000000000..ce315cbaa6
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain3.s
> @@ -0,0 +1,19 @@
> +/* The retention of bar should also prevent foo from being gc'ed, since bar
> + references foo. */
> + .section .text.foo,"ax"
> + .global foo
> + .type foo, %function
> +foo:
> + .word 0
> +
> + .section .text.bar,"axR"
> + .global bar
> + .type bar, %function
> +bar:
> + .long foo
> +
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> diff --git a/ld/testsuite/ld-elf/retain4.d b/ld/testsuite/ld-elf/retain4.d
> new file mode 100644
> index 0000000000..e94898d681
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain4.d
> @@ -0,0 +1,10 @@
> +#name: SHF_GNU_RETAIN 4 (keep orphaned sections when not discarding)
> +#source: retain4.s
> +#ld: -e _start --gc-sections --orphan-handling=place
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> +#DUMPPROG: nm
> +
> +#...
> +[0-9a-f]+ . orphaned_fn
> +#pass
> diff --git a/ld/testsuite/ld-elf/retain4.s b/ld/testsuite/ld-elf/retain4.s
> new file mode 100644
> index 0000000000..9f350cd3b2
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain4.s
> @@ -0,0 +1,13 @@
> +/* A section which doesn't match any linker script input section rules but
> + has SHF_GNU_RETAIN applied should not be garbage collected. */
> + .section .orphaned_section,"axR"
> + .global orphaned_fn
> + .type orphaned_fn, %function
> +orphaned_fn:
> + .word 0
> +
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> diff --git a/ld/testsuite/ld-elf/retain5.d b/ld/testsuite/ld-elf/retain5.d
> new file mode 100644
> index 0000000000..378799599e
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain5.d
> @@ -0,0 +1,12 @@
> +#name: SHF_GNU_RETAIN 5 (don't pull SHF_GNU_RETAIN section out of lib)
> +#source: retain5main.s
> +#ld: --gc-sections -e _start --print-gc-sections -Ltmpdir -lretain5 -Map=retain5.map
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> +#map: retain5.map
> +#DUMPPROG: nm
> +
> +#failif
> +#...
> +[0-9a-f]+ . foo
> +#...
> diff --git a/ld/testsuite/ld-elf/retain5.map b/ld/testsuite/ld-elf/retain5.map
> new file mode 100644
> index 0000000000..6b97c2a220
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain5.map
> @@ -0,0 +1,5 @@
> +# Check that the library was actually loaded to catch any false PASS.
> +
> +#...
> +LOAD tmpdir/libretain5.a
> +#pass
> diff --git a/ld/testsuite/ld-elf/retain5lib.s b/ld/testsuite/ld-elf/retain5lib.s
> new file mode 100644
> index 0000000000..4e83731719
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain5lib.s
> @@ -0,0 +1,6 @@
> +/* The link will fail if foo is included because undefined_sym is not defined. */
> + .section .text.foo,"axR"
> + .global foo
> + .type foo, %function
> +foo:
> + .long undefined_sym
> diff --git a/ld/testsuite/ld-elf/retain5main.s b/ld/testsuite/ld-elf/retain5main.s
> new file mode 100644
> index 0000000000..89a7784d13
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain5main.s
> @@ -0,0 +1,5 @@
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> diff --git a/ld/testsuite/ld-elf/retain6a.d b/ld/testsuite/ld-elf/retain6a.d
> new file mode 100644
> index 0000000000..92872deffc
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain6a.d
> @@ -0,0 +1,14 @@
> +#name: SHF_GNU_RETAIN 6a (pull section out of lib required by SHF_GNU_RETAIN section)
> +#source: retain6main.s
> +#ld: --gc-sections -e _start -u bar -Ltmpdir -lretain6
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> +#DUMPPROG: nm
> +
> +#...
> +[0-9a-f]+ . bar
> +#...
> +[0-9a-f]+ . retain_from_lib
> +#...
> +[0-9a-f]+ . retained_fn
> +#pass
> diff --git a/ld/testsuite/ld-elf/retain6b.d b/ld/testsuite/ld-elf/retain6b.d
> new file mode 100644
> index 0000000000..a797bf7837
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain6b.d
> @@ -0,0 +1,11 @@
> +#name: SHF_GNU_RETAIN 6b (pull section out of lib required by SHF_GNU_RETAIN section)
> +#source: retain6main.s
> +#ld: --gc-sections -e _start -u bar -Ltmpdir -lretain6
> +#skip: mep-*-* dlx-*-* d30v-*-* pj-*-* pru-*-* xgate-*-* s12z-*-*
> +#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
> +#DUMPPROG: nm
> +
> +#failif
> +#...
> +[0-9a-f]+ . .*discard.*
> +#...
> diff --git a/ld/testsuite/ld-elf/retain6lib.s b/ld/testsuite/ld-elf/retain6lib.s
> new file mode 100644
> index 0000000000..a393dbac61
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain6lib.s
> @@ -0,0 +1,17 @@
> + .section .text.bar,"ax"
> + .global bar
> + .type bar, %function
> +bar:
> + .word 0
> +
> + .section .text.retain_from_lib,"axR"
> + .global retain_from_lib
> + .type retain_from_lib, %function
> +retain_from_lib:
> + .word 0
> +
> + .section .text.discard_from_lib,"ax"
> + .global discard_from_lib
> + .type discard_from_lib, %function
> +discard_from_lib:
> + .word 0
> diff --git a/ld/testsuite/ld-elf/retain6main.s b/ld/testsuite/ld-elf/retain6main.s
> new file mode 100644
> index 0000000000..a66c5b3247
> --- /dev/null
> +++ b/ld/testsuite/ld-elf/retain6main.s
> @@ -0,0 +1,13 @@
> +/* Undefined symbol reference in retained section .text.retained_fn requires
> + symbol definition to be pulled out of library. */
> + .section .text.retained_fn,"axR"
> + .global retained_fn
> + .type retained_fn, %function
> +retained_fn:
> + .long bar
> +
> + .section .text._start,"ax"
> + .global _start
> + .type _start, %function
> +_start:
> + .word 0
> --
> 2.28.0
>
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From 3a89108b2a9e466be7fe82a0f19cd6978d96e3ec Mon Sep 17 00:00:00 2001
From: Jozef Lawrynowicz <jozef.l@mittosystems.com>
Date: Mon, 19 Oct 2020 20:43:17 +0100
Subject: [PATCH] Support SHF_GNU_RETAIN ELF section flag
The SHF_GNU_RETAIN section flag is an extension to the GNU ELF OSABI.
It is defined as follows:
=======================================================================
Section Attribute Flags
+-------------------------------------+
| Name | Value |
+-------------------------------------+
| SHF_GNU_RETAIN | 0x200000 (1 << 21) |
+-------------------------------------+
SHF_GNU_RETAIN
The link editor should not garbage collect the section.
=======================================================================
Note that there is not a direct mapping of SHF_GNU_RETAIN to the BFD
section flag SEC_KEEP. This would prevent the user being able to
explicitly remove an SHF_GNU_RETAIN section by placing it in /DISCARD/.
bfd/ChangeLog:
2020-10-19 Jozef Lawrynowicz <jozef.l@mittosystems.com>
H.J. Lu <hongjiu.lu@intel.com>
* elf-bfd.h (enum elf_gnu_osabi): Add elf_gnu_osabi_retain.
(struct elf_obj_tdata): Increase has_gnu_osabi to 4 bits.
* elf.c (_bfd_elf_make_section_from_shdr): Set elf_gnu_osabi_retain
for SHF_GNU_RETAIN.
(_bfd_elf_final_write_processing): Report if SHF_GNU_RETAIN is
not supported by the OSABI.
Adjust error messages.
* elflink.c (bfd_elf_gc_sections): gc_mark the section if
SHF_GNU_RETAIN is set.
binutils/ChangeLog:
2020-10-19 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* NEWS: Announce SHF_GNU_RETAIN.
* readelf.c (get_elf_section_flags): Handle SHF_GNU_RETAIN.
Recognize SHF_GNU_RETAIN and SHF_GNU_MBIND only for supported OSABIs.
* testsuite/binutils-all/readelf.exp: Run new tests.
Don't run run_dump_test when there isn't an assembler available.
* testsuite/lib/binutils-common.exp (supports_gnu_osabi): Adjust
comment.
* testsuite/binutils-all/readelf-maskos-1a.d: New test.
* testsuite/binutils-all/readelf-maskos-1b.d: New test.
* testsuite/binutils-all/readelf-maskos.s: New test.
* testsuite/binutils-all/retain1.s: New test.
* testsuite/binutils-all/retain1a.d: New test.
* testsuite/binutils-all/retain1b.d: New test.
gas/ChangeLog:
2020-10-19 Jozef Lawrynowicz <jozef.l@mittosystems.com>
H.J. Lu <hongjiu.lu@intel.com>
* NEWS: Announce SHF_GNU_RETAIN.
* config/obj-elf.c (get_section_by_match): Update struct member name.
(obj_elf_change_section): Warn/error for state change of SHF_GNU_RETAIN.
(obj_elf_parse_section_letters): Handle 'R' flag.
Handle numeric flag values within the SHF_MASKOS range.
(obj_elf_section): Validate SHF_GNU_RETAIN usage.
* config/obj-elf.h (struct elf_section_match): Adjust "info" member
name to "sh_info". Add "sh_flags" member.
* doc/as.texi (Section): Document 'R' flag.
* testsuite/gas/elf/elf.exp: Run new tests.
* testsuite/gas/elf/section10.d: Don't test SHF_GNU_RETAIN bit of
section flag.
* testsuite/gas/elf/section10.s: Don't set SHF_GNU_RETAIN bit of
section flag.
* testsuite/gas/elf/section22.d: New test.
* testsuite/gas/elf/section22.s: New test.
* testsuite/gas/elf/section23.s: New test.
* testsuite/gas/elf/section23a.d: New test.
* testsuite/gas/elf/section23b.d: New test.
* testsuite/gas/elf/section23b.err: New test.
* testsuite/gas/elf/section24.d: New test.
* testsuite/gas/elf/section24.l: New test.
* testsuite/gas/elf/section24.s: New test.
include/ChangeLog:
2020-10-19 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* elf/common.h (SHF_GNU_RETAIN): Define.
ld/ChangeLog:
2020-10-19 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* NEWS: Announce SHF_GNU_RETAIN.
* ld.texi (garbage collection): Document SHF_GNU_RETAIN.
(Output Section Discarding): Likewise.
* testsuite/ld-elf/elf.exp: Run new tests.
* testsuite/ld-elf/retain1.s: New test.
* testsuite/ld-elf/retain1a.d: New test.
* testsuite/ld-elf/retain1b.d: New test.
* testsuite/ld-elf/retain2.d: New test.
* testsuite/ld-elf/retain2.ld: New test.
* testsuite/ld-elf/retain2.map: New test.
* testsuite/ld-elf/retain3.d: New test.
* testsuite/ld-elf/retain3.s: New test.
* testsuite/ld-elf/retain4.d: New test.
* testsuite/ld-elf/retain4.s: New test.
* testsuite/ld-elf/retain5.d: New test.
* testsuite/ld-elf/retain5.map: New test.
* testsuite/ld-elf/retain5lib.s: New test.
* testsuite/ld-elf/retain5main.s: New test.
* testsuite/ld-elf/retain6a.d: New test.
* testsuite/ld-elf/retain6b.d: New test.
* testsuite/ld-elf/retain6lib.s: New test.
* testsuite/ld-elf/retain6main.s: New test.
---
bfd/elf-bfd.h | 9 +-
bfd/elf.c | 17 ++-
bfd/elflink.c | 4 +-
binutils/NEWS | 4 +
binutils/readelf.c | 51 ++++++++-
.../binutils-all/readelf-maskos-1a.d | 10 ++
.../binutils-all/readelf-maskos-1b.d | 12 ++
.../testsuite/binutils-all/readelf-maskos.s | 11 ++
binutils/testsuite/binutils-all/readelf.exp | 9 +-
binutils/testsuite/binutils-all/retain1.s | 104 ++++++++++++++++++
binutils/testsuite/binutils-all/retain1a.d | 18 +++
binutils/testsuite/binutils-all/retain1b.d | 46 ++++++++
binutils/testsuite/lib/binutils-common.exp | 5 +-
gas/NEWS | 5 +
gas/config/obj-elf.c | 88 +++++++++++----
gas/config/obj-elf.h | 3 +-
gas/doc/as.texi | 3 +
gas/testsuite/gas/elf/elf.exp | 5 +-
gas/testsuite/gas/elf/section10.d | 4 +-
gas/testsuite/gas/elf/section10.s | 4 +-
gas/testsuite/gas/elf/section22.d | 19 ++++
gas/testsuite/gas/elf/section22.s | 34 ++++++
gas/testsuite/gas/elf/section23.s | 11 ++
gas/testsuite/gas/elf/section23a.d | 11 ++
gas/testsuite/gas/elf/section23b.d | 6 +
gas/testsuite/gas/elf/section23b.err | 2 +
gas/testsuite/gas/elf/section24.d | 18 +++
gas/testsuite/gas/elf/section24.l | 4 +
gas/testsuite/gas/elf/section24.s | 32 ++++++
include/elf/common.h | 1 +
ld/NEWS | 4 +
ld/ld.texi | 7 ++
ld/testsuite/ld-elf/elf.exp | 11 ++
ld/testsuite/ld-elf/retain1.s | 104 ++++++++++++++++++
ld/testsuite/ld-elf/retain1a.d | 27 +++++
ld/testsuite/ld-elf/retain1b.d | 10 ++
ld/testsuite/ld-elf/retain2.d | 5 +
ld/testsuite/ld-elf/retain2.ld | 7 ++
ld/testsuite/ld-elf/retain2.map | 32 ++++++
ld/testsuite/ld-elf/retain3.d | 11 ++
ld/testsuite/ld-elf/retain3.s | 19 ++++
ld/testsuite/ld-elf/retain4.d | 9 ++
ld/testsuite/ld-elf/retain4.s | 13 +++
ld/testsuite/ld-elf/retain5.d | 11 ++
ld/testsuite/ld-elf/retain5.map | 5 +
ld/testsuite/ld-elf/retain5lib.s | 6 +
ld/testsuite/ld-elf/retain5main.s | 5 +
ld/testsuite/ld-elf/retain6a.d | 13 +++
ld/testsuite/ld-elf/retain6b.d | 10 ++
ld/testsuite/ld-elf/retain6lib.s | 17 +++
ld/testsuite/ld-elf/retain6main.s | 13 +++
51 files changed, 845 insertions(+), 44 deletions(-)
create mode 100644 binutils/testsuite/binutils-all/readelf-maskos-1a.d
create mode 100644 binutils/testsuite/binutils-all/readelf-maskos-1b.d
create mode 100644 binutils/testsuite/binutils-all/readelf-maskos.s
create mode 100644 binutils/testsuite/binutils-all/retain1.s
create mode 100644 binutils/testsuite/binutils-all/retain1a.d
create mode 100644 binutils/testsuite/binutils-all/retain1b.d
create mode 100644 gas/testsuite/gas/elf/section22.d
create mode 100644 gas/testsuite/gas/elf/section22.s
create mode 100644 gas/testsuite/gas/elf/section23.s
create mode 100644 gas/testsuite/gas/elf/section23a.d
create mode 100644 gas/testsuite/gas/elf/section23b.d
create mode 100644 gas/testsuite/gas/elf/section23b.err
create mode 100644 gas/testsuite/gas/elf/section24.d
create mode 100644 gas/testsuite/gas/elf/section24.l
create mode 100644 gas/testsuite/gas/elf/section24.s
create mode 100644 ld/testsuite/ld-elf/retain1.s
create mode 100644 ld/testsuite/ld-elf/retain1a.d
create mode 100644 ld/testsuite/ld-elf/retain1b.d
create mode 100644 ld/testsuite/ld-elf/retain2.d
create mode 100644 ld/testsuite/ld-elf/retain2.ld
create mode 100644 ld/testsuite/ld-elf/retain2.map
create mode 100644 ld/testsuite/ld-elf/retain3.d
create mode 100644 ld/testsuite/ld-elf/retain3.s
create mode 100644 ld/testsuite/ld-elf/retain4.d
create mode 100644 ld/testsuite/ld-elf/retain4.s
create mode 100644 ld/testsuite/ld-elf/retain5.d
create mode 100644 ld/testsuite/ld-elf/retain5.map
create mode 100644 ld/testsuite/ld-elf/retain5lib.s
create mode 100644 ld/testsuite/ld-elf/retain5main.s
create mode 100644 ld/testsuite/ld-elf/retain6a.d
create mode 100644 ld/testsuite/ld-elf/retain6b.d
create mode 100644 ld/testsuite/ld-elf/retain6lib.s
create mode 100644 ld/testsuite/ld-elf/retain6main.s
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 140a98594d..ffb75f7919 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -1897,14 +1897,15 @@ struct output_elf_obj_tdata
bfd_boolean flags_init;
};
-/* Indicate if the bfd contains SHF_GNU_MBIND sections or symbols that
- have the STT_GNU_IFUNC symbol type or STB_GNU_UNIQUE binding. Used
- to set the osabi field in the ELF header structure. */
+/* Indicate if the bfd contains SHF_GNU_MBIND/SHF_GNU_RETAIN sections or
+ symbols that have the STT_GNU_IFUNC symbol type or STB_GNU_UNIQUE
+ binding. Used to set the osabi field in the ELF header structure. */
enum elf_gnu_osabi
{
elf_gnu_osabi_mbind = 1 << 0,
elf_gnu_osabi_ifunc = 1 << 1,
elf_gnu_osabi_unique = 1 << 2,
+ elf_gnu_osabi_retain = 1 << 3,
};
typedef struct elf_section_list
@@ -2034,7 +2035,7 @@ struct elf_obj_tdata
ENUM_BITFIELD (dynamic_lib_link_class) dyn_lib_class : 4;
/* Whether the bfd uses OS specific bits that require ELFOSABI_GNU. */
- ENUM_BITFIELD (elf_gnu_osabi) has_gnu_osabi : 3;
+ ENUM_BITFIELD (elf_gnu_osabi) has_gnu_osabi : 4;
/* Whether if the bfd contains the GNU_PROPERTY_NO_COPY_ON_PROTECTED
property. */
diff --git a/bfd/elf.c b/bfd/elf.c
index 9d7cbd52e0..dc097e825a 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -1066,9 +1066,12 @@ _bfd_elf_make_section_from_shdr (bfd *abfd,
/* FIXME: We should not recognize SHF_GNU_MBIND for ELFOSABI_NONE,
but binutils as of 2019-07-23 did not set the EI_OSABI header
byte. */
- case ELFOSABI_NONE:
case ELFOSABI_GNU:
case ELFOSABI_FREEBSD:
+ if ((hdr->sh_flags & SHF_GNU_RETAIN) != 0)
+ elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_retain;
+ /* Fall through */
+ case ELFOSABI_NONE:
if ((hdr->sh_flags & SHF_GNU_MBIND) != 0)
elf_tdata (abfd)->has_gnu_osabi |= elf_gnu_osabi_mbind;
break;
@@ -12464,11 +12467,17 @@ _bfd_elf_final_write_processing (bfd *abfd)
&& i_ehdrp->e_ident[EI_OSABI] != ELFOSABI_FREEBSD)
{
if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_mbind)
- _bfd_error_handler (_("GNU_MBIND section is unsupported"));
+ _bfd_error_handler (_("GNU_MBIND section is supported only by GNU "
+ "and FreeBSD targets"));
if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_ifunc)
- _bfd_error_handler (_("symbol type STT_GNU_IFUNC is unsupported"));
+ _bfd_error_handler (_("symbol type STT_GNU_IFUNC is supported "
+ "only by GNU and FreeBSD targets"));
if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_unique)
- _bfd_error_handler (_("symbol binding STB_GNU_UNIQUE is unsupported"));
+ _bfd_error_handler (_("symbol binding STB_GNU_UNIQUE is supported "
+ "only by GNU and FreeBSD targets"));
+ if (elf_tdata (abfd)->has_gnu_osabi & elf_gnu_osabi_retain)
+ _bfd_error_handler (_("GNU_RETAIN section is supported "
+ "only by GNU and FreeBSD targets"));
bfd_set_error (bfd_error_sorry);
return FALSE;
}
diff --git a/bfd/elflink.c b/bfd/elflink.c
index e23d189b98..742254055c 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -14103,7 +14103,9 @@ bfd_elf_gc_sections (bfd *abfd, struct bfd_link_info *info)
== SHT_FINI_ARRAY)))
|| (elf_section_data (o)->this_hdr.sh_type == SHT_NOTE
&& elf_next_in_group (o) == NULL
- && elf_linked_to_section (o) == NULL)))
+ && elf_linked_to_section (o) == NULL)
+ || ((elf_tdata (sub)->has_gnu_osabi & elf_gnu_osabi_retain)
+ && (elf_section_flags (o) & SHF_GNU_RETAIN))))
{
if (!_bfd_elf_gc_mark (info, o, gc_mark_hook))
return FALSE;
diff --git a/binutils/NEWS b/binutils/NEWS
index c0dc73d7d8..ceea7731c5 100644
--- a/binutils/NEWS
+++ b/binutils/NEWS
@@ -4,6 +4,10 @@
symbol names. In addition the --demangle=<style>, --no-demangle,
--recurse-limit and --no-recurse-limit options are also now availale.
+* Add support for the SHF_GNU_RETAIN ELF section flag.
+ This flag specifies that the section should not be garbage collected by the
+ linker.
+
Changes in 2.35:
* Changed readelf's display of symbol names when wide mode is not enabled.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 9ba4e29a65..e6ec99a2cc 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -5977,6 +5977,8 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
/* 24 */ { STRING_COMMA_LEN ("GNU_MBIND") },
/* VLE specific. */
/* 25 */ { STRING_COMMA_LEN ("VLE") },
+ /* GNU specific. */
+ /* 26 */ { STRING_COMMA_LEN ("GNU_RETAIN") },
};
if (do_section_details)
@@ -6009,7 +6011,6 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
case SHF_TLS: sindex = 9; break;
case SHF_EXCLUDE: sindex = 18; break;
case SHF_COMPRESSED: sindex = 20; break;
- case SHF_GNU_MBIND: sindex = 24; break;
default:
sindex = -1;
@@ -6061,10 +6062,26 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
if (flag == SHF_PPC_VLE)
sindex = 25;
break;
+ }
+ switch (filedata->file_header.e_ident[EI_OSABI])
+ {
+ case ELFOSABI_GNU:
+ case ELFOSABI_FREEBSD:
+ if (flag == SHF_GNU_RETAIN)
+ sindex = 26;
+ /* Fall through */
+ case ELFOSABI_NONE:
+ if (flag == SHF_GNU_MBIND)
+ /* We should not recognize SHF_GNU_MBIND for
+ ELFOSABI_NONE, but binutils as of 2019-07-23 did
+ not set the EI_OSABI header byte. */
+ sindex = 24;
+ break;
default:
break;
}
+ break;
}
if (sindex != -1)
@@ -6107,7 +6124,6 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
case SHF_TLS: *p = 'T'; break;
case SHF_EXCLUDE: *p = 'E'; break;
case SHF_COMPRESSED: *p = 'C'; break;
- case SHF_GNU_MBIND: *p = 'D'; break;
default:
if ((filedata->file_header.e_machine == EM_X86_64
@@ -6117,14 +6133,37 @@ get_elf_section_flags (Filedata * filedata, bfd_vma sh_flags)
*p = 'l';
else if (filedata->file_header.e_machine == EM_ARM
&& flag == SHF_ARM_PURECODE)
- *p = 'y';
+ *p = 'y';
else if (filedata->file_header.e_machine == EM_PPC
&& flag == SHF_PPC_VLE)
- *p = 'v';
+ *p = 'v';
else if (flag & SHF_MASKOS)
{
- *p = 'o';
- sh_flags &= ~ SHF_MASKOS;
+ switch (filedata->file_header.e_ident[EI_OSABI])
+ {
+ case ELFOSABI_GNU:
+ case ELFOSABI_FREEBSD:
+ if (flag == SHF_GNU_RETAIN)
+ {
+ *p = 'R';
+ break;
+ }
+ /* Fall through */
+ case ELFOSABI_NONE:
+ if (flag == SHF_GNU_MBIND)
+ {
+ /* We should not recognize SHF_GNU_MBIND for
+ ELFOSABI_NONE, but binutils as of 2019-07-23 did
+ not set the EI_OSABI header byte. */
+ *p = 'D';
+ break;
+ }
+ /* Fall through */
+ default:
+ *p = 'o';
+ sh_flags &= ~SHF_MASKOS;
+ break;
+ }
}
else if (flag & SHF_MASKPROC)
{
diff --git a/binutils/testsuite/binutils-all/readelf-maskos-1a.d b/binutils/testsuite/binutils-all/readelf-maskos-1a.d
new file mode 100644
index 0000000000..7b27358599
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf-maskos-1a.d
@@ -0,0 +1,10 @@
+#name: Unknown SHF_MASKOS value in section
+#source: readelf-maskos.s
+#notarget: [supports_gnu_osabi] msp430-*-elf visium-*-elf
+#xfail: arm-*-elf
+#readelf: -S --wide
+# PR26722 for the arm-*-elf XFAIL
+
+#...
+ \[[ 0-9]+\] .data.retain_var.*WAo.*
+#pass
diff --git a/binutils/testsuite/binutils-all/readelf-maskos-1b.d b/binutils/testsuite/binutils-all/readelf-maskos-1b.d
new file mode 100644
index 0000000000..2cbb58a73b
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf-maskos-1b.d
@@ -0,0 +1,12 @@
+#name: -t (section details) for unknown SHF_MASKOS value in section
+#source: readelf-maskos.s
+#notarget: [supports_gnu_osabi] msp430-*-elf visium-*-elf
+#xfail: arm-*-elf
+#readelf: -S -t --wide
+# PR26722 for the arm-*-elf XFAIL
+
+#...
+ \[[ 0-9]+\] .data.retain_var
+ PROGBITS +0+ +[0-9a-f]+ +[0-9a-f]+ +[0-9a-f]+ +0 +0 +(1|2|4|8)
+ \[00200003\]: WRITE, ALLOC, OS \(00200000\)
+#pass
diff --git a/binutils/testsuite/binutils-all/readelf-maskos.s b/binutils/testsuite/binutils-all/readelf-maskos.s
new file mode 100644
index 0000000000..d671119bca
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf-maskos.s
@@ -0,0 +1,11 @@
+ .section .data.retain_var,"0x200003"
+ .global retain_var
+ .type retain_var, %object
+retain_var:
+ .long 2
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/binutils/testsuite/binutils-all/readelf.exp b/binutils/testsuite/binutils-all/readelf.exp
index 1fb36ae5c4..9d1d496e5c 100644
--- a/binutils/testsuite/binutils-all/readelf.exp
+++ b/binutils/testsuite/binutils-all/readelf.exp
@@ -364,8 +364,15 @@ readelf_wi_test
readelf_compressed_wa_test
readelf_dump_test
-run_dump_test "pr25543"
+# These dump tests require an assembler.
+if {[which $AS] != 0} then {
+ run_dump_test "pr25543"
+ run_dump_test "retain1a"
+ run_dump_test "retain1b"
+ run_dump_test "readelf-maskos-1a"
+ run_dump_test "readelf-maskos-1b"
+}
# PR 13482 - Check for off-by-one errors when dumping .note sections.
if {![binutils_assemble $srcdir/$subdir/version.s tmpdir/version.o]} then {
diff --git a/binutils/testsuite/binutils-all/retain1.s b/binutils/testsuite/binutils-all/retain1.s
new file mode 100644
index 0000000000..f7716faabe
--- /dev/null
+++ b/binutils/testsuite/binutils-all/retain1.s
@@ -0,0 +1,104 @@
+ .global discard0
+ .section .bss.discard0,"aw"
+ .type discard0, %object
+discard0:
+ .zero 2
+
+ .global discard1
+ .section .bss.discard1,"aw"
+ .type discard1, %object
+discard1:
+ .zero 2
+
+ .global discard2
+ .section .data.discard2,"aw"
+ .type discard2, %object
+discard2:
+ .word 1
+
+ .section .bss.sdiscard0,"aw"
+ .type sdiscard0, %object
+sdiscard0:
+ .zero 2
+
+ .section .bss.sdiscard1,"aw"
+ .type sdiscard1, %object
+sdiscard1:
+ .zero 2
+
+ .section .data.sdiscard2,"aw"
+ .type sdiscard2, %object
+sdiscard2:
+ .word 1
+
+ .section .text.fndiscard0,"ax"
+ .global fndiscard0
+ .type fndiscard0, %function
+fndiscard0:
+ .word 0
+
+ .global retain0
+ .section .bss.retain0,"awR"
+ .type retain0, %object
+retain0:
+ .zero 2
+
+ .global retain1
+ .section .bss.retain1,"awR"
+ .type retain1, %object
+retain1:
+ .zero 2
+
+ .global retain2
+ .section .data.retain2,"awR"
+ .type retain2, %object
+retain2:
+ .word 1
+
+ .section .bss.sretain0,"awR"
+ .type sretain0, %object
+sretain0:
+ .zero 2
+
+ .section .bss.sretain1,"awR"
+ .type sretain1, %object
+sretain1:
+ .zero 2
+
+ .section .data.sretain2,"aRw"
+ .type sretain2, %object
+sretain2:
+ .word 1
+
+ .section .text.fnretain1,"Rax"
+ .global fnretain1
+ .type fnretain1, %function
+fnretain1:
+ .word 0
+
+ .section .text.fndiscard2,"ax"
+ .global fndiscard2
+ .type fndiscard2, %function
+fndiscard2:
+ .word 0
+
+ .section .bss.lsretain0,"awR"
+ .type lsretain0.2, %object
+lsretain0.2:
+ .zero 2
+
+ .section .bss.lsretain1,"aRw"
+ .type lsretain1.1, %object
+lsretain1.1:
+ .zero 2
+
+ .section .data.lsretain2,"aRw"
+ .type lsretain2.0, %object
+lsretain2.0:
+ .word 1
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/binutils/testsuite/binutils-all/retain1a.d b/binutils/testsuite/binutils-all/retain1a.d
new file mode 100644
index 0000000000..6397ac52ae
--- /dev/null
+++ b/binutils/testsuite/binutils-all/retain1a.d
@@ -0,0 +1,18 @@
+#name: readelf SHF_GNU_RETAIN
+#source: retain1.s
+#target: [supports_gnu_osabi]
+#readelf: -S --wide
+
+#...
+ \[[ 0-9]+\] .bss.retain0.*WAR.*
+ \[[ 0-9]+\] .bss.retain1.*WAR.*
+ \[[ 0-9]+\] .data.retain2.*WAR.*
+ \[[ 0-9]+\] .bss.sretain0.*WAR.*
+ \[[ 0-9]+\] .bss.sretain1.*WAR.*
+ \[[ 0-9]+\] .data.sretain2.*WAR.*
+ \[[ 0-9]+\] .text.fnretain1.*AXR.*
+#...
+ \[[ 0-9]+\] .bss.lsretain0.*WAR.*
+ \[[ 0-9]+\] .bss.lsretain1.*WAR.*
+ \[[ 0-9]+\] .data.lsretain2.*WAR.*
+#pass
diff --git a/binutils/testsuite/binutils-all/retain1b.d b/binutils/testsuite/binutils-all/retain1b.d
new file mode 100644
index 0000000000..12bc388ba1
--- /dev/null
+++ b/binutils/testsuite/binutils-all/retain1b.d
@@ -0,0 +1,46 @@
+#name: -t (section details) for readelf SHF_GNU_RETAIN
+#source: retain1.s
+#target: [supports_gnu_osabi]
+#readelf: -S -t --wide
+
+#...
+ \[[ 0-9]+\] .bss.retain0
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.retain1
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .data.retain2
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.sretain0
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.sretain1
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .data.sretain2
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .text.fnretain1
+#...
+ \[0+200006\]: ALLOC, EXEC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.lsretain0
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .bss.lsretain1
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#...
+ \[[ 0-9]+\] .data.lsretain2
+#...
+ \[0+200003\]: WRITE, ALLOC, GNU_RETAIN
+#pass
diff --git a/binutils/testsuite/lib/binutils-common.exp b/binutils/testsuite/lib/binutils-common.exp
index b9a1e6e4bc..a43639bafb 100644
--- a/binutils/testsuite/lib/binutils-common.exp
+++ b/binutils/testsuite/lib/binutils-common.exp
@@ -195,13 +195,15 @@ proc match_target { target } {
# True if the ELF target supports setting the ELF header OSABI field
# to ELFOSABI_GNU or ELFOSABI_FREEBSD, a requirement for STT_GNU_IFUNC
-# symbol and SHF_GNU_MBIND section support.
+# symbol and SHF_GNU_MBIND or SHF_GNU_RETAIN section support.
#
# This generally depends on the target OS only, however there are a
# number of exceptions for bare metal targets as follows. The MSP430
# and Visium targets set OSABI to ELFOSABI_STANDALONE. Likewise
# non-EABI ARM targets set OSABI to ELFOSABI_ARM
#
+# Non-Linux HPPA defaults to ELFOSABI_HPUX.
+#
# Note that some TI C6X targets use ELFOSABI_C6000_* but one doesn't,
# so we don't try to sort out tic6x here. (The effect is that linker
# testcases will generally need to exclude tic6x or use a -m option.)
@@ -227,6 +229,7 @@ proc supports_gnu_osabi {} {
}
if { [istarget "arm*-*-*"]
|| [istarget "msp430-*-*"]
+ || [istarget "hppa-unknown-elf"]
|| [istarget "visium-*-*"] } {
return 0
}
diff --git a/gas/NEWS b/gas/NEWS
index 1107725ea6..33005b5904 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -30,6 +30,11 @@
* Configure with --enable-x86-used-note by default for Linux/x86.
+* Add support for the "R" flag in the .section directive.
+ This flag requires ELFOSABI_GNU or ELFOSABI_FREEBSD, and applies the
+ ELF SHF_GNU_RETAIN flag to the specified section. This flag specifies
+ the section should not be garbage collected by the linker.
+
Changes in 2.35:
* X86 NaCl target support is removed.
diff --git a/gas/config/obj-elf.c b/gas/config/obj-elf.c
index f061ea61f3..6586478975 100644
--- a/gas/config/obj-elf.c
+++ b/gas/config/obj-elf.c
@@ -529,9 +529,9 @@ get_section_by_match (bfd *abfd ATTRIBUTE_UNUSED, asection *sec, void *inf)
const char *group_name = elf_group_name (sec);
const char *linked_to_symbol_name
= sec->map_head.linked_to_symbol_name;
- unsigned int info = elf_section_data (sec)->this_hdr.sh_info;
+ unsigned int sh_info = elf_section_data (sec)->this_hdr.sh_info;
- return (info == match->info
+ return (sh_info == match->sh_info
&& ((bfd_section_flags (sec) & SEC_ASSEMBLER_SECTION_ID)
== (match->flags & SEC_ASSEMBLER_SECTION_ID))
&& sec->section_id == match->section_id
@@ -740,7 +740,7 @@ obj_elf_change_section (const char *name,
type = bfd_elf_get_default_section_type (flags);
elf_section_type (sec) = type;
elf_section_flags (sec) = attr;
- elf_section_data (sec)->this_hdr.sh_info = match_p->info;
+ elf_section_data (sec)->this_hdr.sh_info = match_p->sh_info;
/* Prevent SEC_HAS_CONTENTS from being inadvertently set. */
if (type == SHT_NOBITS)
@@ -798,7 +798,10 @@ obj_elf_change_section (const char *name,
& (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
| SEC_EXCLUDE | SEC_SORT_ENTRIES | SEC_MERGE | SEC_STRINGS
| SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD
- | SEC_THREAD_LOCAL)))
+ | SEC_THREAD_LOCAL))
+ || ((elf_tdata (stdoutput)->has_gnu_osabi & elf_gnu_osabi_retain)
+ && ((elf_section_flags (old_sec) ^ match_p->sh_flags)
+ & SHF_GNU_RETAIN)))
{
if (ssect != NULL)
as_warn (_("ignoring changed section attributes for %s"), name);
@@ -861,6 +864,9 @@ obj_elf_parse_section_letters (char *str, size_t len,
case 'd':
*gnu_attr |= SHF_GNU_MBIND;
break;
+ case 'R':
+ *gnu_attr |= SHF_GNU_RETAIN;
+ break;
case '?':
*is_clone = TRUE;
break;
@@ -890,8 +896,32 @@ obj_elf_parse_section_letters (char *str, size_t len,
if (ISDIGIT (*str))
{
char * end;
+ struct elf_backend_data *bed;
+ bfd_vma numeric_flags = strtoul (str, &end, 0);
+
+ attr |= numeric_flags;
+
+ bed = (struct elf_backend_data *)
+ get_elf_backend_data (stdoutput);
+
+ if (bed->elf_osabi == ELFOSABI_NONE
+ || bed->elf_osabi == ELFOSABI_STANDALONE
+ || bed->elf_osabi == ELFOSABI_GNU
+ || bed->elf_osabi == ELFOSABI_FREEBSD)
+ {
+ /* Add flags in the SHF_MASKOS range to gnu_attr for
+ OSABIs that support those flags.
+ Also adding the flags for ELFOSABI_{NONE,STANDALONE}
+ allows them to be validated later in obj_elf_section.
+ We can't just always set these bits in gnu_attr for
+ all OSABIs, since Binutils does not recognize all
+ SHF_MASKOS bits for non-GNU OSABIs. It's therefore
+ possible that numeric flags are being used to set bits
+ in the SHF_MASKOS range for those targets, and we
+ don't want assembly to fail in those situations. */
+ *gnu_attr |= (numeric_flags & SHF_MASKOS);
+ }
- attr |= strtoul (str, & end, 0);
/* Update str and len, allowing for the fact that
we will execute str++ and len-- below. */
end --;
@@ -1287,18 +1317,21 @@ obj_elf_section (int push)
if (ISDIGIT (* input_line_pointer))
{
char *t = input_line_pointer;
- match.info = strtoul (input_line_pointer,
+ match.sh_info = strtoul (input_line_pointer,
&input_line_pointer, 0);
- if (match.info == (unsigned int) -1)
+ if (match.sh_info == (unsigned int) -1)
{
as_warn (_("unsupported mbind section info: %s"), t);
- match.info = 0;
+ match.sh_info = 0;
}
}
else
input_line_pointer = save;
}
+ if ((gnu_attr & SHF_GNU_RETAIN) != 0)
+ match.sh_flags |= SHF_GNU_RETAIN;
+
if (*input_line_pointer == ',')
{
char *save = input_line_pointer;
@@ -1387,26 +1420,39 @@ obj_elf_section (int push)
done:
demand_empty_rest_of_line ();
- obj_elf_change_section (name, type, attr, entsize, &match, linkonce,
- push);
-
- if ((gnu_attr & SHF_GNU_MBIND) != 0)
+ if ((gnu_attr & (SHF_GNU_MBIND | SHF_GNU_RETAIN)) != 0)
{
struct elf_backend_data *bed;
+ bfd_boolean mbind_p = (gnu_attr & SHF_GNU_MBIND) != 0;
- if ((attr & SHF_ALLOC) == 0)
+ if (mbind_p && (attr & SHF_ALLOC) == 0)
as_bad (_("SHF_ALLOC isn't set for GNU_MBIND section: %s"), name);
bed = (struct elf_backend_data *) get_elf_backend_data (stdoutput);
- if (bed->elf_osabi == ELFOSABI_NONE)
- bed->elf_osabi = ELFOSABI_GNU;
- else if (bed->elf_osabi != ELFOSABI_GNU
- && bed->elf_osabi != ELFOSABI_FREEBSD)
- as_bad (_("GNU_MBIND section is supported only by GNU "
- "and FreeBSD targets"));
- elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_mbind;
+
+ if (bed->elf_osabi != ELFOSABI_GNU
+ && bed->elf_osabi != ELFOSABI_FREEBSD
+ && bed->elf_osabi != ELFOSABI_NONE)
+ {
+ as_bad (_("%s section is supported only by GNU and FreeBSD targets"),
+ mbind_p ? "GNU_MBIND" : "GNU_RETAIN");
+ }
+ else
+ {
+ if (bed->elf_osabi == ELFOSABI_NONE)
+ bed->elf_osabi = ELFOSABI_GNU;
+
+ if (mbind_p)
+ elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_mbind;
+ if ((gnu_attr & SHF_GNU_RETAIN) != 0)
+ elf_tdata (stdoutput)->has_gnu_osabi |= elf_gnu_osabi_retain;
+
+ attr |= gnu_attr;
+ }
}
- elf_section_flags (now_seg) |= gnu_attr;
+
+ obj_elf_change_section (name, type, attr, entsize, &match, linkonce,
+ push);
if (linked_to_section_index != -1UL)
{
diff --git a/gas/config/obj-elf.h b/gas/config/obj-elf.h
index 4f29572eef..0a91ed462f 100644
--- a/gas/config/obj-elf.h
+++ b/gas/config/obj-elf.h
@@ -106,8 +106,9 @@ struct elf_section_match
{
const char * group_name;
const char * linked_to_symbol_name;
- unsigned int info;
unsigned int section_id;
+ unsigned int sh_info; /* ELF section information. */
+ bfd_vma sh_flags; /* ELF section flags. */
flagword flags;
};
diff --git a/gas/doc/as.texi b/gas/doc/as.texi
index 4d5294552a..e92432a8bd 100644
--- a/gas/doc/as.texi
+++ b/gas/doc/as.texi
@@ -6657,6 +6657,9 @@ section is a member of a section group
section is used for thread-local-storage
@item ?
section is a member of the previously-current section's group, if any
+@item R
+retained section (apply SHF_GNU_RETAIN to prevent linker garbage
+collection, GNU ELF extension)
@item @code{<number>}
a numeric value indicating the bits to be set in the ELF section header's flags
field. Note - if one or more of the alphabetic characters described above is
diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
index 9d75154483..49d5a47959 100644
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@@ -261,8 +261,11 @@ if { [is_elf_format] } then {
run_dump_test "section19"
run_dump_test "section20"
run_dump_test "section21"
+ run_dump_test "section22"
+ run_dump_test "section23a"
+ run_dump_test "section23b"
+ run_dump_test "section24"
run_dump_test "sh-link-zero"
-
run_dump_test "dwarf2-1" $dump_opts
run_dump_test "dwarf2-2" $dump_opts
run_dump_test "dwarf2-3" $dump_opts
diff --git a/gas/testsuite/gas/elf/section10.d b/gas/testsuite/gas/elf/section10.d
index 554a791f1d..6aa7b088b1 100644
--- a/gas/testsuite/gas/elf/section10.d
+++ b/gas/testsuite/gas/elf/section10.d
@@ -18,7 +18,7 @@
#...
[ ]*\[.*\][ ]+sec3
[ ]*PROGBITS.*
-[ ]*\[.*fefff030\]: MERGE, STRINGS,.* EXCLUDE, OS \(.*ef00000\), PROC \(.*[3467]0000000\), UNKNOWN \(0+0ff000\)
+[ ]*\[.*fedff030\]: MERGE, STRINGS,.* EXCLUDE, OS \(.*ed00000\), PROC \(.*[3467]0000000\), UNKNOWN \(0+0ff000\)
#...
[ ]*\[.*\][ ]+sec4
[ ]*LOOS\+0x11[ ].*
@@ -26,7 +26,7 @@
#...
[ ]*\[.*\][ ]+sec5
[ ]*LOUSER\+0x9[ ].*
-[ ]*\[.*feff0000\]:.* EXCLUDE, OS \(.*ef00000\), PROC \(.*[3467]0000000\), UNKNOWN \(.*f0000\)
+[ ]*\[.*fedf0000\]:.* EXCLUDE, OS \(.*ed00000\), PROC \(.*[3467]0000000\), UNKNOWN \(.*f0000\)
[ ]*\[.*\][ ]+.data.foo
[ ]*LOUSER\+0x7f000000[ ].*
[ ]*\[0+003\]: WRITE, ALLOC
diff --git a/gas/testsuite/gas/elf/section10.s b/gas/testsuite/gas/elf/section10.s
index 29f1184523..d52b3458fb 100644
--- a/gas/testsuite/gas/elf/section10.s
+++ b/gas/testsuite/gas/elf/section10.s
@@ -7,7 +7,7 @@
.word 2
# Make sure that specifying further arguments to .sections is still supported
- .section sec3, "0xfefff000MS", %progbits, 32
+ .section sec3, "0xfedff000MS", %progbits, 32
.word 3
# Make sure that extra flags can be set for well known sections as well.
@@ -19,7 +19,7 @@
.word 5
# Test both together, with a quoted type value.
- .section sec5, "0xfeff0000", "0x80000009"
+ .section sec5, "0xfedf0000", "0x80000009"
.word 6
# Test that declaring an extended version of a known special section works.
diff --git a/gas/testsuite/gas/elf/section22.d b/gas/testsuite/gas/elf/section22.d
new file mode 100644
index 0000000000..8aa7fcfc34
--- /dev/null
+++ b/gas/testsuite/gas/elf/section22.d
@@ -0,0 +1,19 @@
+#readelf: -h -S --wide
+#name: SHF_GNU_RETAIN sections 22
+#notarget: ![supports_gnu_osabi]
+
+#...
+ +OS/ABI: +UNIX - GNU
+#...
+ \[..\] .text.discard0[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX.*
+#...
+ \[..\] .data.discard1[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA.*
+#...
+ \[..\] .bss.discard2[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WA.*
+#...
+ \[..\] .bss.retain0[ ]+NOBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
+#...
+ \[..\] .data.retain1[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
+#...
+ \[..\] .text.retain2[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR.*
+#pass
diff --git a/gas/testsuite/gas/elf/section22.s b/gas/testsuite/gas/elf/section22.s
new file mode 100644
index 0000000000..66ed990e57
--- /dev/null
+++ b/gas/testsuite/gas/elf/section22.s
@@ -0,0 +1,34 @@
+ .section .text.discard0,"ax",%progbits
+ .global discard0
+ .type discard0, %function
+discard0:
+ .word 0
+
+ .section .data.discard1,"aw"
+ .global discard1
+ .type discard1, %object
+discard1:
+ .word 1
+
+ .section .bss.discard2,"aw"
+ .global discard2
+ .type discard2, %object
+discard2:
+ .zero 2
+
+ .section .bss.retain0,"awR",%nobits
+ .global retain0
+ .type retain0, %object
+retain0:
+ .zero 2
+
+ .section .data.retain1,"awR",%progbits
+ .type retain1, %object
+retain1:
+ .word 1
+
+ .section .text.retain2,"axR",%progbits
+ .global retain2
+ .type retain2, %function
+retain2:
+ .word 0
diff --git a/gas/testsuite/gas/elf/section23.s b/gas/testsuite/gas/elf/section23.s
new file mode 100644
index 0000000000..d671119bca
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23.s
@@ -0,0 +1,11 @@
+ .section .data.retain_var,"0x200003"
+ .global retain_var
+ .type retain_var, %object
+retain_var:
+ .long 2
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/gas/testsuite/gas/elf/section23a.d b/gas/testsuite/gas/elf/section23a.d
new file mode 100644
index 0000000000..1d850d9e8e
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23a.d
@@ -0,0 +1,11 @@
+#name: SHF_GNU_RETAIN set with numeric flag value in .section
+#source: section23.s
+#target: [supports_gnu_osabi]
+#readelf: -h -S --wide
+
+#...
+ +OS/ABI: +UNIX - GNU
+#...
+ \[..\] .data.retain_var[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 WAR.*
+#pass
+
diff --git a/gas/testsuite/gas/elf/section23b.d b/gas/testsuite/gas/elf/section23b.d
new file mode 100644
index 0000000000..c85200e5ff
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23b.d
@@ -0,0 +1,6 @@
+#name: SHF_GNU_RETAIN set with numeric flag value in .section for non-GNU OSABI target
+#source: section23.s
+#error_output: section23b.err
+#target: msp430-*-elf visium-*-elf
+
+# This test only runs for targets which set ELFOSABI_STANDALONE.
diff --git a/gas/testsuite/gas/elf/section23b.err b/gas/testsuite/gas/elf/section23b.err
new file mode 100644
index 0000000000..83de60c397
--- /dev/null
+++ b/gas/testsuite/gas/elf/section23b.err
@@ -0,0 +1,2 @@
+.*: Assembler messages:
+.*:1: Error: GNU_RETAIN section is supported only by GNU and FreeBSD targets
diff --git a/gas/testsuite/gas/elf/section24.d b/gas/testsuite/gas/elf/section24.d
new file mode 100644
index 0000000000..5ee4aee3af
--- /dev/null
+++ b/gas/testsuite/gas/elf/section24.d
@@ -0,0 +1,18 @@
+#name: Warn for SHF_GNU_RETAIN set on existing section
+#notarget: ![supports_gnu_osabi] rx-*-*
+#readelf: -h -S --wide
+#warning_output: section24.l
+# rx-*-* does not automatically create a ".text" section when starting assembly.
+
+#...
+ +OS/ABI: +UNIX - GNU
+#...
+ \[..\] .text[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX .*
+#...
+ \[..\] .text[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR .*
+#...
+ \[..\] .text.foo[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AXR .*
+#...
+ \[..\] .text.bar[ ]+PROGBITS[ ]+[0-9a-f]+ [0-9a-f]+ [0-9a-f]+ 00 AX .*
+#pass
+
diff --git a/gas/testsuite/gas/elf/section24.l b/gas/testsuite/gas/elf/section24.l
new file mode 100644
index 0000000000..e0ea36078c
--- /dev/null
+++ b/gas/testsuite/gas/elf/section24.l
@@ -0,0 +1,4 @@
+[^:]*: Assembler messages:
+[^:]*:4: Warning: ignoring changed section attributes for .text
+[^:]*:20: Warning: ignoring changed section attributes for .text.foo
+[^:]*:30: Warning: ignoring changed section attributes for .text.bar
diff --git a/gas/testsuite/gas/elf/section24.s b/gas/testsuite/gas/elf/section24.s
new file mode 100644
index 0000000000..deaff0a323
--- /dev/null
+++ b/gas/testsuite/gas/elf/section24.s
@@ -0,0 +1,32 @@
+/* The default .text section automatically created by the assembler does not
+ have the SHF_GNU_RETAIN flag set, so the "R" flag cannot be used with that,
+ or any other, default section. */
+ .section .text,"axR",%progbits
+retain_bad:
+ .word 0
+
+/* A unique .text section with SHF_GNU_RETAIN applied can be created. */
+ .section .text,"axR",%progbits,unique,0
+retain_good:
+ .word 0
+
+/* SHF_GNU_RETAIN can be applied to a new section. */
+ .section .text.foo,"axR",%progbits
+foo_retain:
+ .word 0
+
+/* If the section is used again without SHF_GNU_RETAIN, a warning should be
+ emitted. */
+ .section .text.foo,"ax",%progbits
+foo:
+ .word 0
+
+ .section .text.bar,"ax",%progbits
+bar:
+ .word 0
+
+/* SHF_GNU_RETAIN cannot be applied to a section which was already explicitly
+ declared without SHF_GNU_RETAIN set. */
+ .section .text.bar,"axR",%progbits
+bar_retain:
+ .word 0
diff --git a/include/elf/common.h b/include/elf/common.h
index 571e21af29..c01e562c78 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -554,6 +554,7 @@
/* #define SHF_MASKOS 0x0F000000 *//* OS-specific semantics */
#define SHF_MASKOS 0x0FF00000 /* New value, Oct 4, 1999 Draft */
#define SHF_GNU_BUILD_NOTE (1 << 20) /* Section contains GNU BUILD ATTRIBUTE notes. */
+#define SHF_GNU_RETAIN (1 << 21) /* Section should not be garbage collected by the linker. */
#define SHF_MASKPROC 0xF0000000 /* Processor-specific semantics */
/* This used to be implemented as a processor specific section flag.
diff --git a/ld/NEWS b/ld/NEWS
index e4ae43b257..c103bcebc4 100644
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -15,6 +15,10 @@
unless you are working on a project that has its own analogue
of symbol tables that are not reflected in the ELF symtabs.
+* Add support for the SHF_GNU_RETAIN ELF section flag.
+ This flag specifies that the section should not be garbage collected by the
+ linker.
+
Changes in 2.35:
* X86 NaCl target support is removed.
diff --git a/ld/ld.texi b/ld/ld.texi
index ee592df6c2..849006f0fb 100644
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -1787,6 +1787,9 @@ specified either by one of the options @samp{--entry},
@samp{--undefined}, or @samp{--gc-keep-exported} or by a @code{ENTRY}
command in the linker script.
+As a GNU extension, ELF input sections marked with the
+@code{SHF_GNU_RETAIN} flag will not be garbage collected.
+
@kindex --print-gc-sections
@kindex --no-print-gc-sections
@cindex garbage collection
@@ -5232,6 +5235,10 @@ The special output section name @samp{/DISCARD/} may be used to discard
input sections. Any input sections which are assigned to an output
section named @samp{/DISCARD/} are not included in the output file.
+This can be used to discard input sections marked with the ELF flag
+@code{SHF_GNU_RETAIN}, which would otherwise have been saved from linker
+garbage collection.
+
Note, sections that match the @samp{/DISCARD/} output section will be
discarded even if they are in an ELF section group which has other
members which are not being discarded. This is deliberate.
diff --git a/ld/testsuite/ld-elf/elf.exp b/ld/testsuite/ld-elf/elf.exp
index f2ff0397c7..bd06ab0d39 100644
--- a/ld/testsuite/ld-elf/elf.exp
+++ b/ld/testsuite/ld-elf/elf.exp
@@ -119,6 +119,17 @@ if { [istarget "i?86-*-*"] || [istarget "x86_64-*-*"] } {
set ASFLAGS "$ASFLAGS -mx86-used-note=no"
}
+# Build libraries required for SHF_GNU_RETAIN tests.
+if { [check_gc_sections_available] && [supports_gnu_osabi] } {
+ run_ld_link_tests [list \
+ [list "Build libretain5.a" "" "" "" \
+ {retain5lib.s} {} "libretain5.a"] \
+ [list "Build libretain6.a" "" "" "" \
+ {retain6lib.s} {} "libretain6.a"] \
+ ]
+}
+
+
set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
foreach t $test_list {
# We need to strip the ".d", but can leave the dirname.
diff --git a/ld/testsuite/ld-elf/retain1.s b/ld/testsuite/ld-elf/retain1.s
new file mode 100644
index 0000000000..f7716faabe
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain1.s
@@ -0,0 +1,104 @@
+ .global discard0
+ .section .bss.discard0,"aw"
+ .type discard0, %object
+discard0:
+ .zero 2
+
+ .global discard1
+ .section .bss.discard1,"aw"
+ .type discard1, %object
+discard1:
+ .zero 2
+
+ .global discard2
+ .section .data.discard2,"aw"
+ .type discard2, %object
+discard2:
+ .word 1
+
+ .section .bss.sdiscard0,"aw"
+ .type sdiscard0, %object
+sdiscard0:
+ .zero 2
+
+ .section .bss.sdiscard1,"aw"
+ .type sdiscard1, %object
+sdiscard1:
+ .zero 2
+
+ .section .data.sdiscard2,"aw"
+ .type sdiscard2, %object
+sdiscard2:
+ .word 1
+
+ .section .text.fndiscard0,"ax"
+ .global fndiscard0
+ .type fndiscard0, %function
+fndiscard0:
+ .word 0
+
+ .global retain0
+ .section .bss.retain0,"awR"
+ .type retain0, %object
+retain0:
+ .zero 2
+
+ .global retain1
+ .section .bss.retain1,"awR"
+ .type retain1, %object
+retain1:
+ .zero 2
+
+ .global retain2
+ .section .data.retain2,"awR"
+ .type retain2, %object
+retain2:
+ .word 1
+
+ .section .bss.sretain0,"awR"
+ .type sretain0, %object
+sretain0:
+ .zero 2
+
+ .section .bss.sretain1,"awR"
+ .type sretain1, %object
+sretain1:
+ .zero 2
+
+ .section .data.sretain2,"aRw"
+ .type sretain2, %object
+sretain2:
+ .word 1
+
+ .section .text.fnretain1,"Rax"
+ .global fnretain1
+ .type fnretain1, %function
+fnretain1:
+ .word 0
+
+ .section .text.fndiscard2,"ax"
+ .global fndiscard2
+ .type fndiscard2, %function
+fndiscard2:
+ .word 0
+
+ .section .bss.lsretain0,"awR"
+ .type lsretain0.2, %object
+lsretain0.2:
+ .zero 2
+
+ .section .bss.lsretain1,"aRw"
+ .type lsretain1.1, %object
+lsretain1.1:
+ .zero 2
+
+ .section .data.lsretain2,"aRw"
+ .type lsretain2.0, %object
+lsretain2.0:
+ .word 1
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain1a.d b/ld/testsuite/ld-elf/retain1a.d
new file mode 100644
index 0000000000..29adb5d2c9
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain1a.d
@@ -0,0 +1,27 @@
+#name: SHF_GNU_RETAIN 1a
+#source: retain1.s
+#ld: -e _start --gc-sections
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . fnretain1
+#...
+[0-9a-f]+ . lsretain0.2
+#...
+[0-9a-f]+ . lsretain1.1
+#...
+[0-9a-f]+ . lsretain2.0
+#...
+[0-9a-f]+ . retain0
+#...
+[0-9a-f]+ . retain1
+#...
+[0-9a-f]+ . retain2
+#...
+[0-9a-f]+ . sretain0
+#...
+[0-9a-f]+ . sretain1
+#...
+[0-9a-f]+ . sretain2
+#pass
diff --git a/ld/testsuite/ld-elf/retain1b.d b/ld/testsuite/ld-elf/retain1b.d
new file mode 100644
index 0000000000..b1cafc9d1c
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain1b.d
@@ -0,0 +1,10 @@
+#name: SHF_GNU_RETAIN 1b
+#source: retain1.s
+#ld: -e _start --gc-sections
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#nm: -n
+
+#failif
+#...
+[0-9a-f]+ . .*discard.*
+#...
diff --git a/ld/testsuite/ld-elf/retain2.d b/ld/testsuite/ld-elf/retain2.d
new file mode 100644
index 0000000000..1a63f51aab
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain2.d
@@ -0,0 +1,5 @@
+#name: SHF_GNU_RETAIN 2 (remove SHF_GNU_RETAIN sections by placing in /DISCARD/)
+#source: retain1.s
+#ld: -e _start -Map=retain2.map --gc-sections --script=retain2.ld
+#map: retain2.map
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
diff --git a/ld/testsuite/ld-elf/retain2.ld b/ld/testsuite/ld-elf/retain2.ld
new file mode 100644
index 0000000000..8ef982753c
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain2.ld
@@ -0,0 +1,7 @@
+SECTIONS
+{
+ /DISCARD/ :
+ {
+ *(.text.fnretain1)
+ }
+}
diff --git a/ld/testsuite/ld-elf/retain2.map b/ld/testsuite/ld-elf/retain2.map
new file mode 100644
index 0000000000..4028aa1f58
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain2.map
@@ -0,0 +1,32 @@
+# Test that .text.fnretain1, which has the SHF_GNU_RETAIN flag, can still be
+# explicitly discarded from the output file.
+
+#...
+Discarded input sections
+
+ .text.*
+#...
+ .data.*
+#...
+ .bss.*
+#...
+ .bss.discard0.*
+#...
+ .bss.discard1.*
+#...
+ .data.discard2.*
+#...
+ .bss.sdiscard0.*
+#...
+ .bss.sdiscard1.*
+#...
+ .data.sdiscard2.*
+#...
+ .text.fndiscard0.*
+#...
+ .text.fnretain1.*
+#...
+ .text.fndiscard2.*
+#...
+Memory Configuration
+#pass
diff --git a/ld/testsuite/ld-elf/retain3.d b/ld/testsuite/ld-elf/retain3.d
new file mode 100644
index 0000000000..3c81a88e51
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain3.d
@@ -0,0 +1,11 @@
+#name: SHF_GNU_RETAIN 3 (keep sections referenced by retained sections)
+#source: retain3.s
+#ld: -e _start --gc-sections
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . bar
+#...
+[0-9a-f]+ . foo
+#pass
diff --git a/ld/testsuite/ld-elf/retain3.s b/ld/testsuite/ld-elf/retain3.s
new file mode 100644
index 0000000000..ce315cbaa6
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain3.s
@@ -0,0 +1,19 @@
+/* The retention of bar should also prevent foo from being gc'ed, since bar
+ references foo. */
+ .section .text.foo,"ax"
+ .global foo
+ .type foo, %function
+foo:
+ .word 0
+
+ .section .text.bar,"axR"
+ .global bar
+ .type bar, %function
+bar:
+ .long foo
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain4.d b/ld/testsuite/ld-elf/retain4.d
new file mode 100644
index 0000000000..b423fb9584
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain4.d
@@ -0,0 +1,9 @@
+#name: SHF_GNU_RETAIN 4 (keep orphaned sections when not discarding)
+#source: retain4.s
+#ld: -e _start --gc-sections --orphan-handling=place
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . orphaned_fn
+#pass
diff --git a/ld/testsuite/ld-elf/retain4.s b/ld/testsuite/ld-elf/retain4.s
new file mode 100644
index 0000000000..9f350cd3b2
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain4.s
@@ -0,0 +1,13 @@
+/* A section which doesn't match any linker script input section rules but
+ has SHF_GNU_RETAIN applied should not be garbage collected. */
+ .section .orphaned_section,"axR"
+ .global orphaned_fn
+ .type orphaned_fn, %function
+orphaned_fn:
+ .word 0
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain5.d b/ld/testsuite/ld-elf/retain5.d
new file mode 100644
index 0000000000..86e85f8da5
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5.d
@@ -0,0 +1,11 @@
+#name: SHF_GNU_RETAIN 5 (don't pull SHF_GNU_RETAIN section out of lib)
+#source: retain5main.s
+#ld: --gc-sections -e _start --print-gc-sections -Ltmpdir -lretain5 -Map=retain5.map
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#map: retain5.map
+#DUMPPROG: nm
+
+#failif
+#...
+[0-9a-f]+ . foo
+#...
diff --git a/ld/testsuite/ld-elf/retain5.map b/ld/testsuite/ld-elf/retain5.map
new file mode 100644
index 0000000000..6b97c2a220
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5.map
@@ -0,0 +1,5 @@
+# Check that the library was actually loaded to catch any false PASS.
+
+#...
+LOAD tmpdir/libretain5.a
+#pass
diff --git a/ld/testsuite/ld-elf/retain5lib.s b/ld/testsuite/ld-elf/retain5lib.s
new file mode 100644
index 0000000000..4e83731719
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5lib.s
@@ -0,0 +1,6 @@
+/* The link will fail if foo is included because undefined_sym is not defined. */
+ .section .text.foo,"axR"
+ .global foo
+ .type foo, %function
+foo:
+ .long undefined_sym
diff --git a/ld/testsuite/ld-elf/retain5main.s b/ld/testsuite/ld-elf/retain5main.s
new file mode 100644
index 0000000000..89a7784d13
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain5main.s
@@ -0,0 +1,5 @@
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain6a.d b/ld/testsuite/ld-elf/retain6a.d
new file mode 100644
index 0000000000..aa93117ae7
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6a.d
@@ -0,0 +1,13 @@
+#name: SHF_GNU_RETAIN 6a (pull section out of lib required by SHF_GNU_RETAIN section)
+#source: retain6main.s
+#ld: --gc-sections -e _start -u bar -Ltmpdir -lretain6
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#...
+[0-9a-f]+ . bar
+#...
+[0-9a-f]+ . retain_from_lib
+#...
+[0-9a-f]+ . retained_fn
+#pass
diff --git a/ld/testsuite/ld-elf/retain6b.d b/ld/testsuite/ld-elf/retain6b.d
new file mode 100644
index 0000000000..f29ba71dd9
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6b.d
@@ -0,0 +1,10 @@
+#name: SHF_GNU_RETAIN 6b (pull section out of lib required by SHF_GNU_RETAIN section)
+#source: retain6main.s
+#ld: --gc-sections -e _start -u bar -Ltmpdir -lretain6
+#notarget: ![supports_gnu_osabi] ![check_gc_sections_available]
+#DUMPPROG: nm
+
+#failif
+#...
+[0-9a-f]+ . .*discard.*
+#...
diff --git a/ld/testsuite/ld-elf/retain6lib.s b/ld/testsuite/ld-elf/retain6lib.s
new file mode 100644
index 0000000000..a393dbac61
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6lib.s
@@ -0,0 +1,17 @@
+ .section .text.bar,"ax"
+ .global bar
+ .type bar, %function
+bar:
+ .word 0
+
+ .section .text.retain_from_lib,"axR"
+ .global retain_from_lib
+ .type retain_from_lib, %function
+retain_from_lib:
+ .word 0
+
+ .section .text.discard_from_lib,"ax"
+ .global discard_from_lib
+ .type discard_from_lib, %function
+discard_from_lib:
+ .word 0
diff --git a/ld/testsuite/ld-elf/retain6main.s b/ld/testsuite/ld-elf/retain6main.s
new file mode 100644
index 0000000000..a66c5b3247
--- /dev/null
+++ b/ld/testsuite/ld-elf/retain6main.s
@@ -0,0 +1,13 @@
+/* Undefined symbol reference in retained section .text.retained_fn requires
+ symbol definition to be pulled out of library. */
+ .section .text.retained_fn,"axR"
+ .global retained_fn
+ .type retained_fn, %function
+retained_fn:
+ .long bar
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
--
2.28.0
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2020-10-09 10:59 [PATCH v3] Support SHF_GNU_RETAIN ELF Section Flag Jozef Lawrynowicz
2020-10-19 19:47 ` Jozef Lawrynowicz
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