[cfe-dev] Distinguishing between clang Window versions

[Edward Diener]

On 7/8/2014 9:24 PM, Alp Toker wrote:
>
> On 08/07/2014 22:21, Edward Diener wrote:
>> On 7/8/2014 1:29 PM, Yaron Keren wrote:
>>> You can create two Windows configurations, one for clang.exe and one for
>>> clang-cl.exe.
>>> These are actually identical but the if I'm not mistaken the driver
>>> behaves differently based on the executable name.
>>> So you have "clang" and "clang-cl" toolsets.
>>
>> That was an early thought but complicates the elegance of having a
>> single Boost Build toolset for clang across Mac, Linux, and Windows.
>
> The ordinary clang driver can do everything clang-cl.exe can do. You
> don't need to use clang-cl.exe at all if you already have a portable
> clang-based build system.
>
> If the standard clang driver is missing something to produce native
> binaries that's what needs to be fixed.

I see where a build of clang on Windows using VC++ produces both 
clang.exe and clang-cl.exe and that they are both the same executables. 
Nonetheless depending on the -target ( or default -target ) passed to 
the clang driver we have different build expectations in Boost Build. In 
Windows When the target mode is VC++ clang emulates VC++ in various ways 
and when the target mode is mingw/gcc clang emulates mingw/gcc. Even 
with the latter on Windows there are a few subtle differences from clang 
on Linux. That is why Boost Build needs to treat them differently from 
within its .jam files.

>
> Alp.
>
>
>>
>>>
>>> Yaron
>>>
>>>
>>>
>>> 2014-07-08 18:13 GMT+03:00 Nico Weber
>>> <thakis at chromium.org
>>> <mailto:thakis at chromium.org>>:
>>>
>>>     On Tue, Jul 8, 2014 at 6:54 AM, Edward Diener
>>>     <eldlistmailingz at tropicsoft.com
>>>     <mailto:eldlistmailingz at tropicsoft.com>>
>>> wrote:
>>>
>>>         Since the two versions for clang on Windows, one using VC++ RTL
>>>         and emulating VC++ to some small extent and the other using
>>>         mingw rtl, are radically different, is there any easy way to
>>>         distinguish between them at pre-execution time.
>>>
>>>         In Boost Build we currently have a single toolset named 'clang'
>>>         for the clang compiler. On Linux it uses a clang-linux.jam file,
>>>         on the Mac it uses a clang-darwin.jam file, and I am trying to
>>>         establish .jam files for using clang on Windows. Essentially I
>>>         can use the clang-linux.jam file with a slight modification if
>>>         the clang version uses mingw, but I need to use a clang-win.jam
>>>         file if the clang version uses VC++. So somewhere early in the
>>>         Boost Build processing I have to determine which 'clang.exe' is
>>>         being used on Windows in order to invoke the proper Boost Build
>>>         jam file for it.
>>>
>>>
>>>     It's not really to different clang binaries as far as I know, just
>>>     the same binary with a different default triple. So you could pass
>>>     an explicit -target parameter to force one compiler behavior over
>>>     the other too. (-target i386-pc-win32 for VC mode,
>>>     -target i386-pc-mingw32 for gcc mode)
>>>
>>>
>>>         Ideas ? Suggestions ?