[cfe-dev] Distinguishing between clang Window versions

[Edward Diener]

On 7/9/2014 6:22 PM, Nico Weber wrote:
> On Wed, Jul 9, 2014 at 3:01 PM, Edward Diener
> <eldlistmailingz at tropicsoft.com
> <mailto:eldlistmailingz at tropicsoft.com>> wrote:
>
>     On 7/9/2014 2:40 PM, Reid Kleckner wrote:
>
>         On Wed, Jul 9, 2014 at 7:09 AM, Edward Diener
>         <eldlistmailingz at tropicsoft.__com
>         <mailto:eldlistmailingz at tropicsoft.com>
>         <mailto:eldlistmailingz at __tropicsoft.com
>         <mailto:eldlistmailingz at tropicsoft.com>>>
>         wrote:
>
>              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.
>
>
>         What kinds of properties of a compiler do you normally check in
>         Boost
>         Build?  If you're willing to do a test compile, you can look for
>         '#if
>         defined(__clang__) && defined(_MSC_VER)' or '#if
>         defined(__clang__) &&
>         defined(__GNUC__)'.
>
>
>     That is another possibility which I will bring up in Boost Build.
>
>     Essentially we need to find out as easily as possible whether a
>     clang executable on Windows targets vc++ or gcc/mingw,
>
>
> I think going forward, the idea is that "clang" will try to be
> gcc-compatible (i.e. target minw), while "clang-cl" will try to be
> cl-compatible and targes vc++.

However clang also creates a clang.exe driver, which is exactly the same 
file as clang-cl.exe, when building clang with VC++.

>
>     while also taking into account the -target option on the command line.
>
>     BTW I could not find in the latest clang 3.5 documentation any
>     mention of the -target option. Likewise, and I am sure you have
>     heard it before, an alphabetical list of all clang options in the
>     documentation, with explanations for each one, would be greatly
>     appreciated.
>
>
> clang --help prints a list of all driver options, with at least some
> help text.

Yes, but the explanation is pretty terse and then the clang docs are 
sometimes missing any explanation for a particular option, leaving the 
end-user to do random guesswork or ask on the clang mailing lists.