Re: [RFA 1/2] Make line tables independent of progspace

[Tom Tromey <tom at tromey dot com>]

>>>>> "Simon" == Simon Marchi <simark@simark.ca> writes:

>> +      auto pc_compare = [=](const CORE_ADDR & pc,
>> +			    const struct linetable_entry & lhs)->bool
>> {
>> -	return pc < lhs.pc;
>> +	return pc < lhs.address (iter_s);
>> };

Simon> Since we know this will be called many times and address() is substantially
Simon> more costly than just reading a CORE_ADDR field, maybe it would be good to
Simon> save it to a variable before and use that in the lambda.

I am not sure this would work, because LHS is what changes here --
std::upper_bound is searching through the line table looking for a
match.

One idea might be to "unrelocate" PC to do the search.  This would make
the search more efficient.  I will try this.

Simon> I was also thinking
Simon> the same thing for the various other calls to address() in this function, since
Simon> sometimes the same value is recomputed multiple times.

I suppose most work could be done on the unrelocated form, with the
address computation happening only at the end.

>> +  /* Set the members of this object from another linetable_entry.  */
>> +  void set (const linetable_entry &other)
>> +  {
>> +    m_line = other.m_line;
>> +    m_pc = other.m_pc;
>> +  }

Simon> This really looks like an assignment operator (the default one would be
Simon> enough).  Is there a reason to have this set overload?  Either way works,
Simon> I'm just curious.

I just did it to keep the names consistent, but I will change it to use
the default operator=.

>> -	  newLineTb->item[newline] = oldLineTb->item[jj];
>> -	  newLineTb->item[newline].line = oldLineTb->item[jj + 1].line;
>> +	  newLineTb->item[newline].set (oldLineTb->item[jj].raw_address (),
>> +					oldLineTb->item[jj + 1].line ());

Simon> The address and the line are inverted here.

Bleah.  Thanks again.

Tom