[PATCH] Remove the stripped group section from linker output
Alan Modra
amodra@gmail.com
Tue Feb 13 12:29:00 GMT 2018
On Tue, Feb 13, 2018 at 08:28:27PM +1030, Alan Modra wrote:
> This is what I'm currently testing. I intend to add some objcopy
> and ld -r tests that check full and partial removal of group sections.
Committed. Please push your testcases.
bfd/
PR 22836
* elf.c (_bfd_elf_fixup_group_sections): Account for removed
relocation sections. If size reduces to just the flag word,
remove that too and mark with SEC_EXCLUDE.
* elflink.c (bfd_elf_final_link): Strip empty group sections.
binutils/
* testsuite/binutils-all/group-7.s,
* testsuite/binutils-all/group-7a.d,
* testsuite/binutils-all/group-7b.d,
* testsuite/binutils-all/group-7c.d: New tests.
* testsuite/binutils-all/objcopy.exp: Run them.
ld/
* testsuite/ld-elf/pr22836-2.d,
* testsuite/ld-elf/pr22836-2.s: New test.
diff --git a/bfd/elf.c b/bfd/elf.c
index 0503154..934052d 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -7604,7 +7604,16 @@ _bfd_elf_fixup_group_sections (bfd *ibfd, asection *discarded)
but the SHT_GROUP section is, then adjust its size. */
else if (s->output_section == discarded
&& isec->output_section != discarded)
- removed += 4;
+ {
+ struct bfd_elf_section_data *elf_sec = elf_section_data (s);
+ removed += 4;
+ if (elf_sec->rel.hdr != NULL
+ && (elf_sec->rel.hdr->sh_flags & SHF_GROUP) != 0)
+ removed += 4;
+ if (elf_sec->rela.hdr != NULL
+ && (elf_sec->rela.hdr->sh_flags & SHF_GROUP) != 0)
+ removed += 4;
+ }
s = elf_next_in_group (s);
if (s == first)
break;
@@ -7614,18 +7623,26 @@ _bfd_elf_fixup_group_sections (bfd *ibfd, asection *discarded)
if (discarded != NULL)
{
/* If we've been called for ld -r, then we need to
- adjust the input section size. This function may
- be called multiple times, so save the original
- size. */
+ adjust the input section size. */
if (isec->rawsize == 0)
isec->rawsize = isec->size;
isec->size = isec->rawsize - removed;
+ if (isec->size <= 4)
+ {
+ isec->size = 0;
+ isec->flags |= SEC_EXCLUDE;
+ }
}
else
{
/* Adjust the output section size when called from
objcopy. */
isec->output_section->size -= removed;
+ if (isec->output_section->size <= 4)
+ {
+ isec->output_section->size = 0;
+ isec->output_section->flags |= SEC_EXCLUDE;
+ }
}
}
}
diff --git a/bfd/elflink.c b/bfd/elflink.c
index d1eb820..6eb47ee 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -11618,6 +11618,13 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
else
o->flags |= SEC_EXCLUDE;
}
+ else if ((o->flags & SEC_GROUP) != 0 && o->size == 0)
+ {
+ /* Remove empty group section from linker output. */
+ o->flags |= SEC_EXCLUDE;
+ bfd_section_list_remove (abfd, o);
+ abfd->section_count--;
+ }
}
/* Count up the number of relocations we will output for each output
diff --git a/binutils/testsuite/binutils-all/group-7.s b/binutils/testsuite/binutils-all/group-7.s
new file mode 100644
index 0000000..5028afc
--- /dev/null
+++ b/binutils/testsuite/binutils-all/group-7.s
@@ -0,0 +1,6 @@
+ .section .data.foo,"awG",%progbits,foo,comdat
+here:
+ .dc.a here
+
+ .section .data2.foo,"awG",%progbits,foo,comdat
+ .dc.a 0
diff --git a/binutils/testsuite/binutils-all/group-7a.d b/binutils/testsuite/binutils-all/group-7a.d
new file mode 100644
index 0000000..fa8db60
--- /dev/null
+++ b/binutils/testsuite/binutils-all/group-7a.d
@@ -0,0 +1,16 @@
+#name: copy removing reloc group member
+#source: group-7.s
+#PROG: objcopy
+#DUMPPROG: readelf
+#objcopy: --remove-section .data.foo
+#readelf: -Sg --wide
+
+#...
+ \[[ 0-9]+\] \.group[ \t]+GROUP[ \t]+.*
+#...
+ \[[ 0-9]+\] \.data2\.foo[ \t]+PROGBITS[ \t0-9a-f]+WAG.*
+#...
+COMDAT group section \[[ 0-9]+\] `\.group' \[foo\] contains 1 section.*
+ \[Index\] Name
+ \[[ 0-9]+\] \.data2\.foo
+#pass
diff --git a/binutils/testsuite/binutils-all/group-7b.d b/binutils/testsuite/binutils-all/group-7b.d
new file mode 100644
index 0000000..b674545
--- /dev/null
+++ b/binutils/testsuite/binutils-all/group-7b.d
@@ -0,0 +1,19 @@
+#name: copy removing non-reloc group member
+#source: group-7.s
+#PROG: objcopy
+#DUMPPROG: readelf
+#objcopy: --remove-section .data2.foo
+#readelf: -Sg --wide
+
+#...
+ \[[ 0-9]+\] \.group[ \t]+GROUP[ \t]+.*
+#...
+ \[[ 0-9]+\] \.data\.foo[ \t]+PROGBITS[ \t0-9a-f]+WAG.*
+#...
+ \[[ 0-9]+\] \.rela?\.data\.foo[ \t]+RELA?[ \t0-9a-f]+IG.*
+#...
+COMDAT group section \[[ 0-9]+\] `\.group' \[foo\] contains 2 sections:
+ \[Index\] Name
+ \[[ 0-9]+\] \.data\.foo
+ \[[ 0-9]+\] \.rela?\.data\.foo
+#pass
diff --git a/binutils/testsuite/binutils-all/group-7c.d b/binutils/testsuite/binutils-all/group-7c.d
new file mode 100644
index 0000000..83e9115
--- /dev/null
+++ b/binutils/testsuite/binutils-all/group-7c.d
@@ -0,0 +1,8 @@
+#name: copy removing reloc and non-reloc group member
+#source: group-7.s
+#PROG: objcopy
+#DUMPPROG: readelf
+#objcopy: -R .data.foo -R .data2.foo
+#readelf: -g --wide
+
+There are no section groups in this file\.
diff --git a/binutils/testsuite/binutils-all/objcopy.exp b/binutils/testsuite/binutils-all/objcopy.exp
index 377f88c..f4a7692 100644
--- a/binutils/testsuite/binutils-all/objcopy.exp
+++ b/binutils/testsuite/binutils-all/objcopy.exp
@@ -1051,6 +1051,9 @@ if [is_elf_format] {
objcopy_test_readelf "GNU_MBIND section" mbind1.s
run_dump_test "group-5"
run_dump_test "group-6"
+ run_dump_test "group-7a"
+ run_dump_test "group-7b"
+ run_dump_test "group-7c"
run_dump_test "copy-1"
run_dump_test "note-1"
if [is_elf64 tmpdir/bintest.o] {
diff --git a/ld/testsuite/ld-elf/pr22836-2.d b/ld/testsuite/ld-elf/pr22836-2.d
new file mode 100644
index 0000000..10133e4
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr22836-2.d
@@ -0,0 +1,7 @@
+#source: pr22836-2.s
+#ld: -r -S
+#readelf: -g --wide
+
+group section \[[ 0-9]+\] `\.group' \[foo\] contains 1 section.*
+ \[Index\] Name
+ \[[ 0-9]+\] \.comment
diff --git a/ld/testsuite/ld-elf/pr22836-2.s b/ld/testsuite/ld-elf/pr22836-2.s
new file mode 100644
index 0000000..77cd83a
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr22836-2.s
@@ -0,0 +1,7 @@
+ .section .debug_macro,"G",%progbits,foo
+ .long .LASF0
+.LASF0:
+ .string "__STDC__ 1"
+
+ .section .comment,"G",%progbits,foo
+ .asciz "hi"
--
Alan Modra
Australia Development Lab, IBM
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