llvm dev - May 2015 - [LLVMdev] Driver::GetProgramPath is unable to find programs with file extension in name

Hello,

We are having a problem with linker lookup on Windows.

When the driver tries to locate a program by its name, e.g. a linker, it 
scans the paths provided by the toolchain using ScanDirForExecutable and 
then, if fails, uses llvm::sys::findProgramByName, which on Windows 
searches the CWD and system path. ScanDirForExecutable disregards file 
extensions, so search in the toolchain-provided dirs on Windows fails. 
llvm::sys::findProgramByName is aware of extensions via the "PATHEXT" 
env variable (it also has ".exe" hardcoded). However, our linker is
not
in the CWD or system path, thus search fails.

ScanDirForExecutable should respect file extenstions like 
findProgramByName does. One way of doing so is to make the system 
dependent llvm::sys::path::access function aware of extensions similarly 
to findProgramByName. Or the whole ScanDirForExecutable can be made 
system dependent and add an extension on Windows before passing the path 
to llvm::sys::fs::can_execute.

Does such a patch look reasonable? Any opinions / ideas will be much 
appreciated.

Thanks.
Kind regards,
Oleg

Sorry this is ancient, but yeah, this idea makes sense. Feel free to cc me
on a patch for it if you're looking into it.

On Thu, May 21, 2015 at 8:55 AM, Oleg Ranevskyy <llvm.mail.list at
gmail.com>
wrote:
> Hello,
>
> We are having a problem with linker lookup on Windows.
>
> When the driver tries to locate a program by its name, e.g. a linker, it
> scans the paths provided by the toolchain using ScanDirForExecutable and
> then, if fails, uses llvm::sys::findProgramByName, which on Windows
> searches the CWD and system path. ScanDirForExecutable disregards file
> extensions, so search in the toolchain-provided dirs on Windows fails.
> llvm::sys::findProgramByName is aware of extensions via the
"PATHEXT" env
> variable (it also has ".exe" hardcoded). However, our linker is
not in the
> CWD or system path, thus search fails.
>
> ScanDirForExecutable should respect file extenstions like
> findProgramByName does. One way of doing so is to make the system dependent
> llvm::sys::path::access function aware of extensions similarly to
> findProgramByName. Or the whole ScanDirForExecutable can be made system
> dependent and add an extension on Windows before passing the path to
> llvm::sys::fs::can_execute.
>
> Does such a patch look reasonable? Any opinions / ideas will be much
> appreciated.
>
> Thanks.
> Kind regards,
> Oleg
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
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Hi Reid,

Thanks for your attention to this!
Ok, I will propose a patch and cc you shortly.

Kind regards,
Oleg


On Fri, Jun 5, 2015 at 3:44 AM, Reid Kleckner <rnk at google.com> wrote:
> Sorry this is ancient, but yeah, this idea makes sense. Feel free to cc me
> on a patch for it if you're looking into it.
>
> On Thu, May 21, 2015 at 8:55 AM, Oleg Ranevskyy <llvm.mail.list at
gmail.com>
> wrote:
>
>> Hello,
>>
>> We are having a problem with linker lookup on Windows.
>>
>> When the driver tries to locate a program by its name, e.g. a linker,
it
>> scans the paths provided by the toolchain using ScanDirForExecutable
and
>> then, if fails, uses llvm::sys::findProgramByName, which on Windows
>> searches the CWD and system path. ScanDirForExecutable disregards file
>> extensions, so search in the toolchain-provided dirs on Windows fails.
>> llvm::sys::findProgramByName is aware of extensions via the
"PATHEXT" env
>> variable (it also has ".exe" hardcoded). However, our linker
is not in the
>> CWD or system path, thus search fails.
>>
>> ScanDirForExecutable should respect file extenstions like
>> findProgramByName does. One way of doing so is to make the system
dependent
>> llvm::sys::path::access function aware of extensions similarly to
>> findProgramByName. Or the whole ScanDirForExecutable can be made system
>> dependent and add an extension on Windows before passing the path to
>> llvm::sys::fs::can_execute.
>>
>> Does such a patch look reasonable? Any opinions / ideas will be much
>> appreciated.
>>
>> Thanks.
>> Kind regards,
>> Oleg
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>
>
>
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