Re: [PATCH v2] Add support for the --readnever command-line option

[Sergio Durigan Junior <sergiodj@redhat.com>]

Thanks for the review, Eli.

On Saturday, November 25 2017, Eli Zaretskii wrote:

>> From: Sergio Durigan Junior <sergiodj@redhat.com>
>> Cc: Joel Brobecker <brobecker@adacore.com>,
>> 	Yao Qi <qiyaoltc@gmail.com>,
>> 	Pedro Alves <palves@redhat.com>,
>> 	Eli Zaretskii <eliz@gnu.org>,
>> 	Sergio Durigan Junior <sergiodj@redhat.com>
>> Date: Fri, 24 Nov 2017 18:01:22 -0500
>> 
>> diff --git a/gdb/NEWS b/gdb/NEWS
>> index 754ce103bd..32229d3cea 100644
>> --- a/gdb/NEWS
>> +++ b/gdb/NEWS
>> @@ -3,6 +3,10 @@
>>  
>>  *** Changes since GDB 8.0
>>  
>> +* New "--readnever" command line option instructs GDB to not read each
>> +  symbol file's symbolic debug information.  This makes startup faster
>> +  but at the expense of not being able to perform symbolic debugging.
>> +
>
> This part is okay, but I would add here as well a hint about the use
> cases this supports.  Like this, for example:
>
>   This option is intended for use cases where symbolic debugging will
>   not be used, e.g., when you only need to dump the debuggee's core.

Good point.  I added the text.

>> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
>> index 00451d243d..f3eef8dfeb 100644
>> --- a/gdb/doc/gdb.texinfo
>> +++ b/gdb/doc/gdb.texinfo
>> @@ -1037,6 +1037,15 @@ Read each symbol file's entire symbol table immediately, rather than
>>  the default, which is to read it incrementally as it is needed.
>>  This makes startup slower, but makes future operations faster.
>>  
>> +@item --readnever
>> +@cindex @code{--readnever}
>> +Do not read each symbol file's symbolic debug information.  This makes
>> +startup faster but at the expense of not being able to perform
>> +symbolic debugging.  DWARF unwind information is also not read,
>> +meaning backtraces may become incomplete or inaccurate.  One use of
>> +this is when a user simply wants to do the following sequence: attach,
>> +dump core, detach.  Loading the debugging information in this case is
>> +an unnecessary cause of delay.
>>  @end table
>>  
>>  @node Mode Options
>> @@ -18486,6 +18495,14 @@ tables by using the @samp{-readnow} option with any of the commands that
>>  load symbol table information, if you want to be sure @value{GDBN} has the
>>  entire symbol table available.
>>  
>> +@kindex readnever
>> +@cindex never read symbols
>> +@cindex symbols, never read
>> +@item symbol-file @r{[} -readnever @r{]} @var{filename}
>> +@itemx file @r{[} -readnever @r{]} @var{filename}
>> +You can instruct @value{GDBN} to never read the symbolic information
>> +contained in @var{filename} by using the @samp{-readnever} option.
>> +
>
> This will cause index entries about "readnever" point to 2 different
> places, with no way for the reader to tell up front which place is
> about where they want to go.  So I suggest to change the index entries
> as follows:
>
>   @cindex @code{--readnever}, command-line option
>   ...
>   @cindex @code{-readnever}, option for symbol-file command
>
> (Note that I switched from @kindex to @cindex, since @kindex is used
> for command names, and -readnever isn't.)

Hm, I see.  To be clear, I copied the entry above, which uses @kindex
for the "readnow" symbol-file command.  Maybe that should be fixed (in
another patch), too?

> Otherwise, the patch for the manual is OK.
>
>> @@ -1183,6 +1213,9 @@ Selection of debuggee and its files:\n\n\
>>    --se=FILE          Use FILE as symbol file and executable file.\n\
>>    --symbols=SYMFILE  Read symbols from SYMFILE.\n\
>>    --readnow          Fully read symbol files on first access.\n\
>> +  --readnever        Do not read symbol files.\n\
>> +                     There is currently a known limitation that this only\n\
>> +                     has an effect on symbol files provided in DWARF format.\n\
>
> The part about its being limited to DWARF should now go away, right?

Right, I forgot to remove this line.  Did it now.

Thanks,

-- 
Sergio
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