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[PATCH] elf: Add -z unique-symbol to avoid duplicated local symbol names

Alan Modra amodra@gmail.com
Sat Sep 12 07:47:15 GMT 2020 
On Wed, Sep 09, 2020 at 09:20:25AM -0700, H.J. Lu via Binutils wrote:
> The symbol string table in the .symtab section is optional and cosmetic.
> The contents of the .symtab section have no impact on run-time execution.
> The symbol names in the symbol string table help distinguish addresses at
> different locations. Add a linker option, -z unique-symbol, to avoid
> duplicated local symbol names in the symbol string table.
> 
> This feature was well received by the livepatch maintainers. It not only
> solves the duplicated local symbol name problem, but also would allow
> livepatch to more precisely locate duplicate symbols in general for
> patching.
> 
> bfd/
> 
> 	PR ld/26391
> 	* elflink.c (elf_final_link_info): Add local_hash_table.
> 	(local_hash_entry): New.
> 	(local_hash_newfunc): Likewise.
> 	(elf_link_output_symstrtab): Append ".COUNT" to duplicated local
> 	symbols.
> 	(bfd_elf_final_link): Initialize and free local_hash_table for
> 	"-z unique-symbol".
> 
> include/
> 
> 	PR ld/26391
> 	* bfdlink.h (bfd_link_info): Add unique_symbol.
> 
> ld/
> 
> 	PR ld/26391
> 	* NEWS: Mention "-z unique-symbol".
> 	* emultempl/elf.em (gld${EMULATION_NAME}_handle_option): Handle
> 	"-z unique-symbol" and "-z nounique-symbol".
> 	* ld.texi: Document "-z unique-symbol" and "-z nounique-symbol".
> 	* lexsup.c (elf_static_list_options): Add "-z unique-symbol" and
> 	"-z nounique-symbol".
> 	* testsuite/ld-elf/elf.exp: Add PR ld/26391 tests.
> 	* testsuite/ld-elf/pr26391.nd: New file.
> 	* testsuite/ld-elf/pr26391.out: Likewise.
> 	* testsuite/ld-elf/pr26391a.c: Likewise.
> 	* testsuite/ld-elf/pr26391b.c: Likewise.
> 	* testsuite/ld-elf/pr26391c.c: Likewise.
> 	* testsuite/ld-elf/pr26391d.c: Likewise.

Looks OK to me.

-- 
Alan Modra
Australia Development Lab, IBM
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