[cfe-dev] Platform header test

[Douglas Gregor]

On Nov 20, 2009, at 11:31 AM, John Thompson wrote:

> Are there any plans for testing compilations of the headers on the  
> various platforms?
>
> I would like to look into getting Visual Studio and Windows headers  
> to compile, and the first step would be to see where we are.
>
> I'm thinking that if we had some tests that just include individual  
> headers and just syntax check them, that would both give us this  
> information, as well as become a regression test.
>
> What I've done locally is to create an "Includes" directory under  
> "test", and put in simple tests of the form:
>
> // RUN: clang -fsyntax-only %s
> #include <stdio.h>
>
> I'm using the clang driver because of the -fms-extension issue.
>
> Since headers might act differently between C and C++, perhaps each  
> test should have two compile commands, one for C and one for C++.   
> (I haven't figured out the right options to do that yet with the  
> clang driver.)
>
> Since stdio.h might include other files, I test those separately.   
> Since these might be platform-specific, I'd use conditionals:
>
> // This test is for Windows only.
> // RUN: clang -fsyntax-only %s
> #if defined(__WIN32__) || defined(__WIN64__)
> #include <crtdefs.h>
> #endif
>
> Platform and complier-specific files probably should be in separate  
> directories, perhaps under Includes, i.e.:
>
> test
>     Includes
>         VisualStudio
>         Windows
>         GNU
>
> I separated VisualStudio and Windows with respect to the files under  
> Visual Studio and those under the Platform SDK also being separated,  
> but they could be combined.
>
> Anyway, let me know what you think.

We definitely want to do this kind of testing. lit actually has some  
support already for "try to syntax-check all of the headers in a given  
directory". Check out, for example, clang/utils/C++Tests/stdc++- 
Syntax, which checks the GCC 4.2.1 C++ headers. Run it from the clang  
source directory with, e.g.,

	lit -sv utils/C++Tests/stdc++-Syntax

	- Doug