On Fri, Apr 5, 2019 at 5:37 PM Martin Liška <mli...@suse.cz> wrote: > On 4/4/19 1:44 PM, Shubham Narlawar wrote: > > On Thu, Apr 4, 2019 at 2:13 PM Martin Liška <mli...@suse.cz> wrote: > > > >> On 4/3/19 6:31 PM, Martin Jambor wrote: > >>> Hello Shubham, > >>> > >>> On Fri, Mar 29 2019, Shubham Narlawar wrote: > >>>> Hi, here is my proposal for the above idea. Please review and suggest > >>>> necessary changes. > >>>> > >>>> > >> > https://docs.google.com/document/d/11MNhuuD7dbwAfSW6ZgFrAys9My1Lw1PuMVcAqeNGr7A/edit?usp=sharing > >>> > >>> I have had a quick look and the proposal seems very nice. > >>> > >>> How did you select the attributes you want to implement in csmith? It > >>> is for example a little strange that you decided to include "pure" but > >>> not "const." If you handle visibility, you might as well consider > >>> throwing in externally_visible too, I guess. As a stretch goal, the > >>> alias function attribute might be useful to exercise nasty paths in GCC > >>> IPA optimizations. > >>> > >>> I assume Andi Kleen has seen this proposal and if he is fine with it, > so > >>> am I. > >>> > >>> Thanks, > >>> > >>> Martin > >>> > >> > >> Hi. > >> > >> Just for the record, Martin Jambor asked me to co-mentor during time > period > >> when Andi will be on vacation (if I'm correct). > >> > > > > I have included your name as co-mentor in my proposal. Is it fine? > > Yes. > > > > > > >> I have couple of questions/ideas about the proposal: > >> > >> 1) I would not spend much time with nested functions, it's quite legacy > >> C extension > >> > > > > Once Andi Kleen suggested that nested functions has lot of potential for > > bugs. > > I will not only just add nested functions but I plan to do integration > > testing along with merging of previously implemented extensions in phase > 3 > > of gsoc timeline > > I would be more interested in lambda functions, which is also kind of a > nested function. >
AFAIK, lambda expressions are strictly based on c++ 11 standard and Csmith is only random C code generator and not C++. In this gsoc timeline, I am extending Csmith for C extensions. > > > > > > >> 2) for functions, I would basically include add potential attribute: > >> > >> > https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes > >> > >> see: > >> gcc/c-family/c-attribs.c:242 > >> const struct attribute_spec c_common_attribute_table[] = > >> ... > >> > > > > > >> I assume potential attributes means attributes that will trigger > different > > components of GCC. Can you point out such potential attributes such as > > alias. > > Basically majority of them can stress a component in GCC. More you add > better coverage > we'll have. I will definitely try to add more attributes rather than mentioned attributes if time permits. > > > > > > > > >> > >> 3) similarly for variables: > >> > >> > https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#Common-Variable-Attributes > > > > > > Few of variables attributes like packed, unused, section, aligned are > > already implemented in Csmith. > > Great then. > > > > > > >> > >> 4) and similarly for types > >> > >> > https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#Common-Type-Attribute > >> < > https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#Common-Type-Attributes > > > > > > 5) One big question about csmith I have. It's quite easy to come up with > a > >> test-case which > >> causes an ICE. But it's more difficult to come up with a test-case that > is > >> miscompiled > >> by a compiler. It's mainly due to an invalid behavior in the generated > >> test-case. > >> One can theoretically catch that with sanitizers (ASAN, UBSAN, ...). But > >> still, it's > >> not easy. Are you considering catching wrong-code issue? > >> > > > > I use option -fsanitize=undefined and valgrind to check undefined > > behaviour. Are there any other ways to check it rather than sanitizers? > > I'm not aware of any others. I'm curious if you we able to find a > wrong-code > with your periodic csmith runner? > > Thanks for working on csmith, > Martin > Thanks. Shubham > > > > > Thanks, > > Shubham > > > > > >> > >> Thanks, > >> Martin > >> > >
