Thanks for review.  Attached PATCH v2 with comment adjustment.

On 2020-07-01, Andrew Burgess wrote:
>* Fangrui Song via Gdb-patches <gdb-patches@sourceware.org> [2020-06-30 16:18:42 -0700]:
>
>> LLD from 11 onwards (https://reviews.llvm.org/D81784) uses -1 to
>> represent a relocation in .debug_line referencing a discarded symbol.
>> Recognize -1 to fix gdb.base/break-on-linker-gcd-function.exp when the
>> linker is a newer LLD.
>>
>> gdb/ChangeLog:
>>
>> 	* dwarf2/read.c (lnp_state_machine::check_line_address): Test -1.
>> ---
>>  gdb/dwarf2/read.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
>> index b097f624b6..7cf2691ae9 100644
>> --- a/gdb/dwarf2/read.c
>> +++ b/gdb/dwarf2/read.c
>> @@ -20380,9 +20380,13 @@ lnp_state_machine::check_line_address (struct dwarf2_cu *cu,
>>    /* If ADDRESS < UNRELOCATED_LOWPC then it's not a usable value, it's outside
>>       the pc range of the CU.  However, we restrict the test to only ADDRESS
>>       values of zero to preserve GDB's previous behaviour which is to handle
>> -     the specific case of a function being GC'd by the linker.  */
>> +     the specific case of a function being GC'd by the linker.
>>
>> -  if (address == 0 && address < unrelocated_lowpc)
>> +     LLD from 11 onwards (https://reviews.llvm.org/D81784) uses -1 to represent
>> +     the tombstone value.
>> +     */
>
>If I understand this correctly then "tombstone value" here is the same
>as "a function being GC'd by the linker".  If that's correct then
>could you just use that phrase please as it is clearer, and matches
>the terminology already used in the comment.

Thanks. Reworded the comment added by
c3b7b696c231416ac90fd9cb7d5ce735b3683356 a bit.

>The trailing '*/' should be on the same line as the end of the
>comment, with two whitespace before it, so '...value.  */'.
>> +
>> +  if ((address == 0 && address < unrelocated_lowpc) || address == (CORE_ADDR)-1)
>
>There should be a whitespace after the cast, so '(CORE_ADDR) -1'.
>
>Thanks,
>Andrewx

clang-format deletes space in `(CORE_ADDR) -1`. I think I need to adjust
some options for my minimal .clang-format ...

% cat .clang-format
BasedOnStyle: GNU

>>      {
>>        /* This line table is for a function which has been
>>  	 GCd by the linker.  Ignore it.  PR gdb/12528 */
>> --
>> 2.27.0.212.ge8ba1cc988-goog
>>