[PATCH][Driver] Teach the clang driver how to correctly parse response files on Windows.

[Andrea Di Biagio]

ping.

Any feedback would be appreciated.
Thanks!

On Thu, Mar 20, 2014 at 3:04 PM, Andrea Di Biagio
<andrea.dibiagio at gmail.com> wrote:
> ping.
>
> On Fri, Mar 14, 2014 at 11:14 AM, Andrea Di Biagio
> <andrea.dibiagio at gmail.com> wrote:
>> Hi,
>>
>> This patch teaches the driver how to use function
>> 'llvm::cl::TokenizeWindowsCommandLine' to correctly parse response
>> files on Windows.
>>
>> Microsoft defines specific rules for parsing c/c++ command-line
>> arguments here: http://msdn.microsoft.com/en-us/library/17w5ykft.aspx
>> .
>> Those rules are currently implemented by function
>> TokenizeWindowsCommandLine in llvm "lib/Support/CommandLine.cpp".
>>
>> However, the clang driver doesn't call that method when the host is
>> WIN32. Instead, we always call function
>> llvm::cl::TokenizeGNUCommandLine.
>>
>> This is problematic, for example, when we have backslashes in a
>> response file (see test backslash-in-response-file.c in the patch).
>>
>> This patch also adds XFAIL win32 to the driver test Driver/at_file.c.
>> That test verifies that the driver correctly expands arguments
>> surrounded by single quotes. On Windows, that test would start failing
>> because, single quotation marks cannot be used to identify single
>> arguments.
>>
>> The fix for Driver/at_file.c is probably not ideal. Adding XFAIL win32
>> means that the test would be an expected failure if the target triple
>> contains 'win32'. This is ok in general if both host and target are
>> the same (i.e. we are not testing a cross-compiler). This is a problem
>> however for cross compilers where the host is win32 but the target is
>> not  win32.
>>
>> At the moment there is no way to tell lit that the test should fail
>> based on the information of the host platform (and not only on the
>> target triple). I have an idea about how to improve LIT and
>> consequently test Driver/at_file.c. If ok, I plan to send another
>> patch for improving it.
>>
>> Please let me know if this patch is ok to submit.
>>
>> Thanks in advance,
>>
>> Andrea Di Biagio
>> SN Systems - Sony Computer Entertainment Group