From: Jon Turney <jon.turney@dronecode.org.uk>
To: Christian Franke <Christian.Franke@t-online.de>
Cc: cygwin-apps@cygwin.com
Subject: Re: cygport may not create debug info if top directory contains a symlink
Date: Sun, 11 Feb 2024 17:01:45 +0000 [thread overview]
Message-ID: <39275431-2f86-45d5-9fa0-88369e63ae40@dronecode.org.uk> (raw)
In-Reply-To: <4b32eb45-e167-9a30-1a67-2fac6e57f39e@t-online.de>
On 30/10/2023 16:37, Christian Franke via Cygwin-apps wrote:
> Jon Turney wrote:
>> On 20/09/2023 11:58, Christian Franke via Cygwin-apps wrote:
>>> Brian Inglis wrote:
>>>> On 2023-09-18 04:41, Christian Franke via Cygwin-apps wrote:
>>>>> Brian Inglis wrote:
>>>>>> On 2023-09-17 08:01, Jon Turney via Cygwin-apps wrote:
>>>>>>> On 16/09/2023 15:17, Christian Franke via Cygwin wrote:
>>>>>>>> Found during tests of busybox package:
>>>>>>>> If the path of the top build directory contains a symlink and
>>>>>>>> the project's build scripts normalize pathnames, no debug info
>>>>>>>> is created by cygport.
>>>>>>>>
>>>>>>>> This is because options like
>>>>>>>> -fdebug-prefix-map=${B}=/usr/src/debug/${PF}
>>>>>>>> have no effect because ${B} contains a symlink but the compiler
>>>>>>>> is run with the real source path.
>>>>>>>
>>>>>>> I think that there was some historical bug with gcc where a
>>>>>>> relative path for the old path in this mapping wasn't correctly
>>>>>>> handled, which is why were using an absolute path here at all.
>>>>>>>
>>>>>>> So changing it to something like [1] (if that works), might be
>>>>>>> better.
>>>>>>>
>>>>>>> [1]
>>>>>>> https://github.com/jon-turney/cygport/commit/4175d456a9184c5cdebd8bfb4b5ba30583cedd66
>>>>
>>>> Should bin/cygport.in:534: not have $B between the == as in line 531:
>>>>
>>>> declare ${flags}+=" -fdebug-prefix-map=${B}=/usr/src/debug/${PF}"
>>>> ...
>>>> declare ${flags}+=" -fdebug-prefix-map==/usr/src/debug/${PF}"
>>>>
>>>> or be hoist above the condition if identical, unless that is some
>>>> undocumented default for cwd?
>>>
>>> I guess the == without ${B} is intentional because it makes the debug
>>> source path relative to ${B} as lines 535-536 also do.
>>
[...]>
>> (It's unclear to me how gcc compares paths to apply this mapping. If
>> it's a literal string prefix, rather than on some (semi-)canonicalized
>> path, then we're maybe going to lose here sometimes, depending on the
>> vagaries of the build-system, unless we list all of relative,
>> absolute, and canonical absolute paths?)
>>
>> (But then maybe we can push dealing with or indicating which of those
>> is correct off onto the individual cygport?)
>>
>
> Adding this if "$(cd ${S} && pwd -P)" != "${S}" should IMO be safe:
> -fdebug-prefix-map=$(cd ${B} && pwd -P)=/usr/src/debug/${PF}
> -fdebug-prefix-map=$(cd ${S} && pwd -P)=/usr/src/debug/${PF}
> (or use realpath)
>
So it seems there's a new flag '-fcanon-prefix-map' in GCC 13, which
looks like it maybe solves this problem.
next prev parent reply other threads:[~2024-02-11 17:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <9bc07a5f-86d9-76ee-f45d-e1956c9035f8@t-online.de>
2023-09-17 14:01 ` Jon Turney
2023-09-17 15:56 ` Brian Inglis
2023-09-18 10:41 ` Christian Franke
2023-09-18 10:58 ` Achim Gratz
2023-09-18 17:24 ` Brian Inglis
2023-09-20 10:58 ` Christian Franke
2023-10-29 16:05 ` Jon Turney
2023-10-30 16:37 ` Christian Franke
2024-02-11 17:01 ` Jon Turney [this message]
2024-04-29 19:44 ` Jon Turney
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