[PATCH v4] PE/COFF: raise normal PE section limit safely

[Alan Modra]

On Tue, Jul 14, 2026 at 10:23:49PM +0200, Oleg Tolmatcev wrote:
> PE/COFF stores symbol section numbers in a 16-bit field.  Binutils used
> signed 16-bit handling there, which limited normal PE objects to 32767
> sections even though MSVC and Clang already accept a larger unsigned
> range.
> 
> Raise the normal PE section limit to 65279, while keeping the PE/COFF
> special section-number values for undefined, absolute and debug symbols
> working correctly.  Do this by decoding and encoding normal PE symbol
> section numbers as unsigned values in the ordinary range, but preserving
> the reserved PE constants explicitly.
> 
> Also add a gas test that exercises a normal PE object above the old
> 32767-section limit and checks that objdump reports the high section
> number correctly.
> 
> bfd/ChangeLog:
> 
> 	* coffcode.h (COFF_DEFAULT_MAX_NSCNS): Define.
> 	(bfd_coff_std_swap_table): Use it for the default maximum section
> 	count.
> 	(ticoff0_swap_table): Likewise.
> 	(ticoff1_swap_table): Likewise.
> 	* peXXigen.c (pe_decode_sym_section_number): New function.
> 	(pe_encode_sym_section_number): New function.
> 	(_bfd_XXi_swap_sym_in): Use pe_decode_sym_section_number.
> 	(_bfd_XXi_swap_sym_out): Use pe_encode_sym_section_number.
> 
> include/ChangeLog:
> 
> 	* coff/pe.h (IMAGE_SYM_UNDEFINED): Define.
> 	(IMAGE_SYM_ABSOLUTE): Define.
> 	(IMAGE_SYM_DEBUG): Define.
> 	(IMAGE_SYM_SECTION_MAX): Define.
> 
> gas/ChangeLog:
> 
> 	* testsuite/gas/pe/pe.exp: Run large-obj-normal.
> 	* testsuite/gas/pe/large-obj-normal.s: New test.
> 	* testsuite/gas/pe/large-obj-normal.d: New test.

This looks OK to me.

-- 
Alan Modra