From: Pedro Alves <pedro@palves.net>
To: Eli Zaretskii <eliz@gnu.org>
Cc: gdb-patches@sourceware.org
Subject: Re: [PATCH v4] gdb/manual: Introduce location specs
Date: Fri, 27 May 2022 20:05:25 +0100 [thread overview]
Message-ID: <977cfe4d-d9d8-98e8-fffb-40c3f9920897@palves.net> (raw)
In-Reply-To: <83o7zin6ua.fsf@gnu.org>
On 2022-05-27 19:55, Eli Zaretskii wrote:
>> Date: Fri, 27 May 2022 19:42:50 +0100
>> Cc: gdb-patches@sourceware.org
>> From: Pedro Alves <pedro@palves.net>
>>
>>> Yes, but note that the last revision of your patch says "resolves
>>> into", not "matches". Which I think is a change for the better; I'm
>>> trying to have a more accurate idea of what that "resolution" entails.
>>
>> Resolution is the act of find all the actual code location that match the user
>> input. The found locations are the resolved code locations.
>>
>> Here for example:
>>
>> +@item list @var{locspec}
>> +Print lines centered around the line or lines that @var{locspec}
>> +resolves to.
>>
>> The meaning is that the user passes some input spec to GDB, which
>> may even not specify any line at all, like "line func", and GDB
>> finds all the matching locations. For each resolved location, you have
>> a resolved line, resolved source file, resolved addr, resolved function, etc.
>
> I understand (I think). But all this does is fill in the attributes
> that were missing from the input location spec. This is done either
> by using the (implied) defaults, like the name of the current file, or
> bhy using the debug info. And if it turns out that some attribute can
> be filled in more than one way, we have a breakpoint with multiple
> code locations. Right?
>
You start with e.g., just one attribute, like "-function func". This
makes GDB iterate over all the functions is knows about, finding the
ones that are called "func". This matches "func(int)", "A::func()",
"func(long)", etc. GDB collects the PC and source file and line number of
those functions too along the wa. If you did "break -function func", then
you end up with a breakpoint with multiple code locations, one
for each function matched.
Or you start with "a/file.c:100". This makes GDB iterate over all source
files it knows about, and then for each that has a file name that ends
with "a/file.c", like e.g., "src/program/a/file.c" and "somelib/a/file.c"
it searches for line 100, collecting the PC and function name of the
location. If you did "break a/file.c:100", you end up with a breakpoint with
multiple locations, one per resolved location. If you did
"list a/file.c:100", GDB lists the source for around each of the locations.
Etc.
Or you start with "*0x1000". Conceptually it's the same. GDB finds the code
locations that match that, resolves that to a location with
PC/function/source/line, and then the command does what it wants with it.
next prev parent reply other threads:[~2022-05-27 19:05 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-26 19:42 Pedro Alves
2022-05-27 14:16 ` Eli Zaretskii
2022-05-27 15:04 ` Pedro Alves
2022-05-27 15:52 ` Eli Zaretskii
2022-05-27 17:11 ` Pedro Alves
2022-05-27 17:31 ` Eli Zaretskii
2022-05-27 17:51 ` Pedro Alves
2022-05-27 18:23 ` Eli Zaretskii
2022-05-27 18:42 ` Pedro Alves
2022-05-27 18:50 ` Pedro Alves
2022-05-27 19:00 ` Eli Zaretskii
2022-05-27 19:30 ` Pedro Alves
2022-05-28 7:43 ` Eli Zaretskii
2022-05-30 14:38 ` Pedro Alves
2022-05-27 18:55 ` Eli Zaretskii
2022-05-27 19:05 ` Pedro Alves [this message]
2022-05-27 19:14 ` Eli Zaretskii
2022-05-27 19:17 ` Pedro Alves
2022-05-27 19:34 ` Eli Zaretskii
2022-05-27 19:38 ` Pedro Alves
2022-05-28 7:39 ` Eli Zaretskii
2022-05-30 14:44 ` [pushed v5] " Pedro Alves
2022-05-30 16:15 ` Eli Zaretskii
2022-05-31 11:05 ` [PATCH] Improve clear command's documentation Pedro Alves
2022-05-31 12:36 ` Eli Zaretskii
2022-05-31 13:04 ` Pedro Alves
2022-05-31 13:42 ` Eli Zaretskii
2022-05-31 14:47 ` Pedro Alves
2022-05-31 16:06 ` Eli Zaretskii
2022-05-31 11:13 ` [PATCH] Explicitly mention yet-unloaded shared libraries in location spec examples Pedro Alves
2022-05-31 11:47 ` Eli Zaretskii
2022-05-31 11:17 ` [pushed v5] gdb/manual: Introduce location specs Pedro Alves
2022-05-31 11:31 ` [PATCH] Improve break-range's documentation Pedro Alves
2022-05-31 11:55 ` Eli Zaretskii
2022-05-31 12:03 ` Pedro Alves
2022-05-31 12:09 ` Eli Zaretskii
2022-06-01 17:17 ` RTe: Location Specs (Was: [pushed v5] gdb/manual: Introduce location specs) Eli Zaretskii
2022-06-02 11:10 ` Pedro Alves
2022-06-02 11:49 ` Eli Zaretskii
2022-06-02 12:40 ` Pedro Alves
2022-06-02 12:56 ` Eli Zaretskii
2022-06-02 13:44 ` Pedro Alves
2022-06-02 16:37 ` Eli Zaretskii
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