Re: [PATCH] Expensive selftests: torture testing for fix-it boundary conditions (PR c/82050)

[Jeff Law <law@redhat.com>]

On 11/28/2017 12:31 PM, David Malcolm wrote:
> This patch adds selftest coverage for the fix for PR c/82050 (r255214).
> 
> The selftest iterates over various "interesting" column and line-width
> values to try to shake out bugs in the fix-it printing routines, a kind
> of "torture" selftest.
> 
> Unfortunately this selftest is noticably slower than the other selftests;
> adding it to diagnostic-show-locus.c led to:
>   -fself-test: 40218 pass(es) in 0.172000 seconds
> slowing down to:
>   -fself-test: 97315 pass(es) in 6.109000 seconds
> for an unoptimized build (e.g. when hacking with --disable-bootstrap).
> 
> Given that this affects the compile-edit-test cycle of the "gcc"
> subdirectory, this felt like an unacceptable amount of overhead to add.
> 
> I attempted to optimize the test by reducing the amount of coverage, but
> the test seems useful, and there seems to be a valid role for "torture"
> selftests.
> 
> Hence this patch adds a:
>   gcc.dg/plugin/expensive_selftests_plugin.c
> with the responsibility for running "expensive" selftests, and adds the
> expensive test there.  The patch moves a small amount of code from
> selftest::run_tests into a helper class so that the plugin can print
> a useful summary line (to reassure us that the tests are actually being
> run).
> 
> With that, the compile-edit-test cycle of the "gcc" subdir is unaffected;
> the plugin takes:
>   expensive_selftests_plugin: 26641 pass(es) in 3.127000 seconds
> which seems reasonable within the much longer time taken by "make check"
> (I optimized some of the overhead away, hence the reduction from 6 seconds
> above down to 3 seconds).
> 
> Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu.
> 
> OK for trunk?
> 
> gcc/ChangeLog:
> 	PR c/82050
> 	* selftest-run-tests.c (selftest::run_tests): Move start/finish code
> 	to...
> 	* selftest.c (selftest::test_runner::test_runner): New ctor.
> 	(selftest::test_runner::~test_runner): New dtor.
> 	* selftest.h (class selftest::test_runner): New class.
> 
> gcc/testsuite/ChangeLog:
> 	PR c/82050
> 	* gcc.dg/plugin/expensive-selftests-1.c: New file.
> 	* gcc.dg/plugin/expensive_selftests_plugin.c: New file.
> 	* gcc.dg/plugin/plugin.exp (plugin_test_list): Add the above.
OK.
jeff