On Fri, May 11, 2012 at 12:47 PM, Frank Loeffler knarf@cct.lsu.edu wrote:
On Fri, May 11, 2012 at 07:57:35AM -0400, Erik Schnetter wrote:
Many of the warnings in auto-generated thorns are harmless, e.g. about unused variables. While it would be possible to remove unused variables from auto-generated thorns, this wouldn't really help -- (1) the compiler already removes them, and (2) the warning is meant to remind people about potential programming errors, which doesn't apply in our case since we checked the code.
It would help to make other, potentially dangerous warnings more visible. At the moment almost everything is just drowned in 'unimportant' warnings which tends to make people ignore all of them.
I hope Ian can manage to remove most of them. Most of that code is auto-generated anyway. We don't have to go in and remove all of them by hand.
As I mentioned (cut from your quote): Using CCTK_DECLARE_UNUSED will make these warnings go away.
The shadowing errors come from thorn Vectors, which uses macros to implement vectorisation. I tried using inline functions, but this made the code unbearably slow except when optimising, and also led to other problems with some compilers (although gcc and Intel were fine). The macros are well-crafted, and these warning regarding shadowing are harmless in this case.
I believe you that they are harmless. I wonder whether we can find a way which makes the compiler happier and doesn't introduce problems. Disabling warnings like globally this isn't really an option, because as you pointed out they can help to find common mistakes in code.
Maybe these warnings should be disabled?
That would mean that a cast from const to not const wouldn't be detected anymore which can potentially lead to problems which are really hard to debug.
I was speaking about the shadowing warnings in Vectors, not about const warnings.
Regarding const, restrict etc: This leads to a warning in C:
double * restrict * x = malloc(...); free(x);
because the call to free (implicitly) casts away the "restrict". It is really difficult to get around these warnings.
You used the warning options "-Wall -Wshadow -Wpointer-arith -Wcast-qual -Wcast-align -Wstrict-prototypes -Wmissing-declarations -Wbad-function-cast -Wsign-compare", which is very exhaustive. Should we use "-Wall" instead by default?
Maybe. Which warnings to enable and to disable is more often than not a matter of taste.
Given that we will setup a regular build at LSU soon anyway, we will capture the build log as well and produce these graphs from them. When we get that for a few different configurations (compilers ect), we should have a good way to see how far we are off that target.
Frank
-----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux)
iQIcBAEBCAAGBQJPrUKzAAoJEOkzpip+I59kr8YQAK+KbOIMGN4hsvljJFcCfeOt 29BUXBZEzzp6tiYqjcs2+CDG3JsrsUycjTDx1j9mbjDggN5CrsFKLplKm7MjBNy9 dwgF26F1s/vCrEQZUncHQ00hEJWtZrqmX5j3SZ/lQocSE375hhQCsULW1TIK56M8 gFsCHloax7Tss1Ucv2z7TAhUYsDHx4MeCqYorj7cE1iNImIcOyXKU1l1Q9hXlyiw KycVlq7oMZW7cfeiUojLcHRMfqSgUi0nvSVthP94Zl1E+wa88agMg12P9dVws3e0 3nEXFIGn68vHFF++81YMLgXUXxcU6QXjTVTD9f1ks2CWhcmwDq7ysvz4IdDj/TlG W9x6FMIntuvlq2xoLVkos0RdEQFVxUHz2cRy1MfrIgNsAizeuV5ImMCytG7YIyTN Qlg3Ch0ZpYgxvEHgIMarAFmPUYXYaCjWpjZM5E09OK3SkZdEP69hjINm570iTAM1 i84Mdaj99gegjL9/kIsoCSGdxO6b8DjazXkta3YNXd4VIcGluvNhkKedsAZEd65d d/gQ9fb7lNSzX5vK3kTFRzqtAxR9JmHNdpHxQXlXWq208c20vO45QU5dm7RtfxFc Kkr/7wpueKvYSI8B5Abknm4O1+/TGZ6x/TE76xM840cAEkEkEMQ/BF1RQbULth3n LTLdwOEZdHRyZwqmOZex =bB8F -----END PGP SIGNATURE-----