[Bug ld/26543] New: bfd_generic_define_common_symbol does not calculate correct alignment when bfd_octets_per_byte > 1 and power_of_two == 0

[tuckkern+sourceware at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26543

            Bug ID: 26543
           Summary: bfd_generic_define_common_symbol does not calculate
                    correct alignment when bfd_octets_per_byte > 1 and
                    power_of_two == 0
           Product: binutils
           Version: 2.34
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: ld
          Assignee: unassigned at sourceware dot org
          Reporter: tuckkern+sourceware at gmail dot com
  Target Milestone: ---

Created attachment 12803
  --> https://sourceware.org/bugzilla/attachment.cgi?id=12803&action=edit
Patch implementing described fix

bfd_generic_define_common_symbol does not calculate the correct alignment for
targets with more than 1 octet per byte if alignment power is less than 1.

3103: linker.c
alignment = bfd_octets_per_byte (output_bfd, section) << power_of_two;

e.g. 
A target has 16-bit bytes and an alignment of 1 byte (2 octets). 

A common variable may be defined as .comm variable,1,1

bfd_log2(1) will calculate alignment_power == 0

Mathematically 2 ** 0 == 1 which would be correct but the above statement will
evaluate to 2.

Instead the statement should check for a power_of_two == 0 condition i.e.
alignment = power_of_two ? bfd_octets_per_byte (output_bfd, section) <<
power_of_two : 1;

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