[PATCH] [2nd try] Show AIX gc'd symbol address adjustments in map file

[Douglas B Rupp]

On 5/12/20 5:05 PM, Alan Modra via Binutils wrote:
> This line should then be something like
>       if (discarded_section (sec))

This test was not revealing for a discarded symbol, it always came up as 
false in my testing.

Fyi: I'm using an old version of binutils (2.23.52.20130704) for testing 
(ultimately this is for a customer of ours who is required to use this 
version due to certification requirements).  That's not your problem of 
course, but I'm just mentioning it in case there's a version issue in 
play here.

My understanding of garbage collection is limited, but it seems to me 
that gc'd symbols and gc'd sections are apples and oranges, so I don't 
see how it will be possible to use a discarded section test.

> or perhaps better, rather than using the bfd macro use the same
> condition as in lang_map for config.print_map_discarded, to determine
> discarded sections.  I'm presuming that those conditions actually work
> for your "AIX XCOFF garbage collected symbols".  Maybe they won't..
I think the same problem will apply here, and it's more difficult to 
test since print_map_discarded doesn't exist in older binutils and the 
target doesn't exist in newer binutils (ppc-lynx178).  Let me know if 
you think it's worth pursuing.
>
> There's also the question of whether the extra symbol info is
> appropriate when printing discarded sections to the map file.  I'd
> think not.  To fix that you'll need to change the interface to
> print_one_symbol so that the void* arg points at a struct containing
> both the section pointer and print_input_section's "is_discarded"
> parameter (which would better be renamed to "printing_discarded").

This issue is independent of the above.  I think it's interesting to 
know if a symbol has been gc'd, but the address info is redundant.  
Something like this then?

.pr            0x00000000100012b0        0x0 ./pack1.o
                 0x00000000100012b0   -->gc .pack1__fooIP
                 0x00000000100012c0   -->gc .pack1__bumIP
.pr            0x00000000100012b0       0x60 ./test1.o

>