[PATCH] gold: Properly align the NT_GNU_PROPERTY_TYPE_0 note

[H.J. Lu]

On Thu, Aug 16, 2018 at 12:21 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Aug 16, 2018 at 11:49 AM, Florian Weimer <fweimer@redhat.com> wrote:
>> On 08/16/2018 07:46 PM, H.J. Lu wrote:
>>>
>>> +  // The NT_GNU_PROPERTY_TYPE_0 note conforms to gABI.
>>> +  const int align_size
>>> +    = ((note_type == elfcpp::NT_GNU_PROPERTY_TYPE_0)
>>> +       ? parameters->target().get_size()
>>> +       : size);
>>
>>
>> Shouldn't the segment alignment be the same as the section alignment?
>
> It should.  But gold doesn't do that.  If you pass --build-id to gold,
> it will put
> 2 note sections with different alignments into the same NOTE segment:
>
> [hjl@gnu-cfl-1 gold]$ ./ld-new x.o --build-id
> [hjl@gnu-cfl-1 gold]$ readelf -l a.out
>
> Elf file type is EXEC (Executable file)
> Entry point 0x400174
> There are 4 program headers, starting at offset 64
>
> Program Headers:
>   Type           Offset             VirtAddr           PhysAddr
>                  FileSiz            MemSiz              Flags  Align
>   LOAD           0x0000000000000000 0x0000000000400000 0x0000000000400000
>                  0x00000000000001b8 0x00000000000001b8  R E    0x1000
>   LOAD           0x0000000000001000 0x0000000000401000 0x0000000000401000
>                  0x0000000000000000 0x0000000000000000  RW     0x1000
>   NOTE           0x0000000000000120 0x0000000000400120 0x0000000000400120
>                  0x0000000000000054 0x0000000000000054  R      0x8
>   GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
>                  0x0000000000000000 0x0000000000000000  RW     0x10
>
>  Section to Segment mapping:
>   Segment Sections...
>    00     .note.gnu.property .note.gnu.build-id .text .eh_frame
>    01     .data .bss
>    02     .note.gnu.property .note.gnu.build-id
>    03
> [hjl@gnu-cfl-1 gold]$

Here is the updated patch to place note sections a PT_NOTE segment with the same
alignment.

OK for master?

-- 
H.J.
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