[cfe-commits] r90577 - in /cfe/trunk: include/clang/Driver/Options.td lib/Driver/Tools.cpp tools/driver/driver.cpp

[Daniel Dunbar]

2009/12/15 Rafael Espíndola <rafael.espindola at gmail.com>:
>> Presumably, but just to make sure we are on the same page I presume
>> you don't really care about relative paths but rather non-canonical
>> paths. A relative path can always be turned into an absolute path that
>> will behave the same, unless its being resolved in multiple contexts?
>>
>> This has been implemented as -resource-dir, so that clang -cc1 should
>> get its resources dir relative to where the driver found itself. Let
>> me know if this works (or doesn't work) for you.
>
> If the absolute path is constructed with something like $(pwd) +
> "../foo/bar" it should.
>
>>> I am not sure if there is any user that depends on gcc's behavior of
>>> using canonical dirs. Since clang and clang-cc are very careful to
>>> always compute it, I assumed you guys did.
>>
>> It's more a side effect of how GetMainExecutable is implemented than
>> an explicit decision. I do personally rely heavily on the ability to
>> make a symlink point to the actual compiler, but that works in the
>> model I outlined.
>>
>>> What is the usecase where a canonical path is necessary? Maybe we
>>> could always use argv[0]? If not, lets try your suggestion of
>>> searching argv[0] first and then the canonical path.
>>
>> The problem with argv[0] is it isn't always correct, and it may point
>> to a symlink. This is why I proposed recursively resolving symbolic
>> links via argv[0], in the cases when argv[0] isn't correct this will
>> fail immediately and we will fall to the canonical path
>>
>>> Is there anything you would like me to implement?
>>
>> If you want to cook up a patch that implements this strategy and
>> verify that it solves the original problem, that would be great. To
>> make sure we are on the same page, this is what I am imagining, in
>> untested pseudo-Python:
>>
>> --
>> def getDriverDirsToSearch(argv0, mainaddr):
>>  while os.path.exists(argv0):
>>      yield argv0
>>      try:
>>        next = readlink(argv0)
>>      except:
>>
>>
>>      argv0 = readlink
>
> You are probably missing a basedir(argv0) at the start and something
> in the except block, but I think it should work.

Ok. Are you going to work on a patch? :)

 - Daniel