Re: [New file] Add testcase to ensure that #pragma GCC diagnostic push/pop works with -Wtraditional.

[David Malcolm <dmalcolm@redhat.com>]

On Fri, 2017-03-24 at 14:10 -0400, Eric Gallager wrote:
> The attached test case failed with gcc 4.9 and older, but started
> compiling successfully with only the 1 expected warning with gcc 5.
> Adding it to the test suite would ensure that this behavior doesn't
> regress. 

Thanks for posting this.

What's the significance of the leading space in the:
 #pragma GCC diagnostic pop
line?  Is *that* the bug?  (did we have a bug # for this, I wonder?)


> Note that I have only tested it by compiling it manually, and
> not by actually running it as part of the entire test suite, so
> please
> let me know if I got any of the dejagnu directives wrong.

When I started contributing to gcc, it took me a while to figure out
how to run just one case in the testsuite, so in case it's helpful I'll
post the recipe here:

1) Find the pertinent Tcl script that runs the test: a .exp script in
the same directory, or one of the ancestors directories.  For this case
it's gcc.dg/dg.exp.  The significant part is the filename: dg.exp

2) Figure out the appropriate "make" target, normally based on the
source language for the test.  For this case it's "check-gcc"

3) Run make in your BUILDDIR/gcc, passing in a suitable value for
RUNTESTFLAGS based on the filename found in step 1 above.
For this case, giving it a couple of "-v" flags for verbosity (so that
we can see the command-line of the compiler invocation) it would be:

$ make -jN && make check-gcc RUNTESTFLAGS="-v -v dg.exp=pragma-diag
-7.c"

(for some N; I like the "make && make check-FOO" construction to ensure
that the compiler is rebuilt before running the tests).

...which leads to a summary of:

# of expected passes		3

which looks good.

You can also use wildcards e.g.:

make -j64 && make check-gcc RUNTESTFLAGS="-v -v dg.exp=pragma-diag-*.c"

(and can use -jN on the "make check-FOO" invocation if there are a lot of tests; I tend not to use it for a small number of tests, to avoid interleaving of output in the logs).

Thanks,
> Eric Gallager
> 
> gcc/testsuite/ChangeLog:
> 
> 2017-03-24  Eric Gallager  <egall@gwmail.gwu.edu>
> 
> 	* gcc.dg/pragma-diag-7.c: New test.

I tested your new test case via the above approach and it looks good to
me.

Although we're meant to only be accepting regression fixes and
documentation fixes right now (stage 4 of gcc 7 development) I feel
that extra test coverage like this also ought to be acceptable.

I don't know if the test case is sufficiently small to be exempt from
the FSF's paperwork requirements here:
  https://gcc.gnu.org/contribute.html
(do you have that paperwork in place?)

Thanks
Dave

>