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From: Tom Tromey <tom@tromey.com>
To: Simon Marchi <simon.marchi@ericsson.com>
Cc: Tom Tromey <tom@tromey.com>,  Simon Marchi <simark@simark.ca>,
	 <gdb-patches@sourceware.org>
Subject: Re: [RFA 1/2] Make line tables independent of progspace
Date: Wed, 28 Mar 2018 04:53:00 -0000	[thread overview]
Message-ID: <87r2o4x0kw.fsf@tromey.com> (raw)
In-Reply-To: <cbfd1765-be31-2e36-6bd7-c922c23fb5a4@ericsson.com> (Simon	Marchi's message of "Tue, 27 Mar 2018 16:22:04 -0400")

>>>>> "Simon" == Simon Marchi <simon.marchi@ericsson.com> writes:

Simon> Here are two small comments I noted.

Thank you.

>> @@ -517,10 +522,12 @@ do_mixed_source_and_assembly (struct gdbarch *gdbarch,
>> first_le = NULL;
>> 
>> /* Skip all the preceding functions.  */
>> -  for (i = 0; i < nlines && le[i].pc < low; i++)
>> -    continue;
>> +  for (i = 0;
>> +       i < nlines - 1 && le[i].address (main_symtab) < low;

Simon> I don't understand why "i < nlines" becomes "i < nlines - 1" here.

Bad change on my part.

>> +  if (lte1->raw_address () < lte2->raw_address ())
>> +    return -1;
>> +  if (lte1->raw_address () > lte2->raw_address ())
>> +    return -1;
>> +  return 0;

Simon> Both branches return -1 here.

Ugh, sorry.  This got introduced during the changes to use member
functions.

Simon> I don't mind the "left - right", I see that often.  Especially when you
Simon> want to sort by multiple fields, it's short and clear (IMO) to do

In this particular case I think it is a bit weird, because the addresses
are unsigned, so this is relying on the implicit cast to make the value
negative.  But also, because the addresses are CORE_ADDR and the return
type is int, it seems like underflow is possible as well (in theory, I
suppose I wouldn't expect it in practice).

So, I thought rather than being tricky here, it was more obviously
correct to just write the longer form.  Which would be true if it didn't
introduce bugs.

Tom

  reply	other threads:[~2018-03-28  4:53 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-21 17:18 [RFA 0/2] " Tom Tromey
2018-03-21 17:18 ` [RFA 2/2] Constify the line table Tom Tromey
2018-03-21 17:18 ` [RFA 1/2] Make line tables independent of progspace Tom Tromey
2018-03-24  3:40   ` Simon Marchi
2018-03-27  4:16     ` Tom Tromey
2018-03-27  4:53       ` Tom Tromey
2018-03-27 20:22         ` Simon Marchi
2018-03-28  4:53           ` Tom Tromey [this message]
2018-03-28 12:30             ` Simon Marchi
2018-03-28  3:34         ` Simon Marchi
2018-03-28  5:02           ` Tom Tromey
2018-03-28 12:32             ` Simon Marchi
2018-03-28 19:33           ` Maciej W. Rozycki
2018-03-29 15:04             ` Simon Marchi
2018-03-29 21:07               ` Maciej W. Rozycki
2018-04-26 21:30                 ` Tom Tromey
2018-05-03 23:17                   ` Maciej W. Rozycki
2018-05-14 23:54                     ` Maciej W. Rozycki

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