PR24015, glibc-2.28 on little-endian mips32 broken

Commit 2bf2bf23da exposed a bug on targets that create common sections
other than the standard ELF SHN_COMMON.  If these are output by ld -r,
then their type becomes SHT_PROGBITS unless the target handles them
specially (eg. by elf_backend_special_sections), and if they are
merged into .bss/.sbss by ld -r then that section becomes SHT_PROGBITS.

Worse, if they are output by ld -r, then their size is increased by
bfd_generic_define_common_symbol during final link, which leads to
bogus file contents being copied to output.

For mips, it seems to me that the .scommon section should not be
output for ld -r, but I haven't made that change in this patch.

	PR 24015
	* elf.c (bfd_elf_get_default_section_type): Make common sections
	SHT_NOBITS.
	* linker.c (bfd_generic_define_common_symbol): Clear
	SEC_HAS_CONTENTS.
This commit is contained in:
Alan Modra 2018-12-28 09:41:44 +10:30
parent cb87d9f1a4
commit 0e41bebb93
3 changed files with 10 additions and 2 deletions

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@ -1,3 +1,11 @@
2018-12-28 Alan Modra <amodra@gmail.com>
PR 24015
* elf.c (bfd_elf_get_default_section_type): Make common sections
SHT_NOBITS.
* linker.c (bfd_generic_define_common_symbol): Clear
SEC_HAS_CONTENTS.
2018-12-28 Alan Modra <amodra@gmail.com>
PR 23966

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@ -3127,7 +3127,7 @@ _bfd_elf_init_reloc_shdr (bfd *abfd,
int
bfd_elf_get_default_section_type (flagword flags)
{
if ((flags & SEC_ALLOC) != 0
if ((flags & (SEC_ALLOC | SEC_IS_COMMON)) != 0
&& (flags & (SEC_LOAD | SEC_HAS_CONTENTS)) == 0)
return SHT_NOBITS;
return SHT_PROGBITS;

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@ -3119,7 +3119,7 @@ bfd_generic_define_common_symbol (bfd *output_bfd,
/* Make sure the section is allocated in memory, and make sure that
it is no longer a common section. */
section->flags |= SEC_ALLOC;
section->flags &= ~SEC_IS_COMMON;
section->flags &= ~(SEC_IS_COMMON | SEC_HAS_CONTENTS);
return TRUE;
}