On April 22, 2016 7:04:31 PM GMT+02:00, Martin Jambor <mjam...@suse.cz> wrote: >Hi, > >this patch adds verification that __builtin_unreachable and >__builtin_trap are not called with arguments. The problem with calls >to them with arguments is that functions like gimple_call_builtin_p >return false on them, because they return true only when >gimple_builtin_call_types_compatible_p does. One manifestation of >that was PR 61591 where undefined behavior sanitizer did not replace >such calls with its thing as it should, but there might be others. > >I have included __builtin_trap in the verification because they often >seem to be handled together but can either remove it or add more >builtins if people think it better. I concede it is a bit arbitrary. > >Honza said he has seen __builtin_unreachable calls with parameters in >LTO builds of Firefox, so it seems this might actually trigger, but I >also think we do not want such calls in the IL. > >I have bootstrapped and tested this on x86_64-linux (with all >languages and Ada) and have also run a C, C++ and Fortran LTO >bootstrap with the patch on the same architecture. OK for trunk?
Shouldn't we simply error in the FEs for this given the builtins essentially have a prototype? That is, error for non-matching args for the __built-in_ variant of _all_ builtins (treat them as prototyped)? Richard. >Thanks, > >Martin > > >2016-04-20 Martin Jambor <mjam...@suse.cz> > > * tree-cfg.c (verify_gimple_call): Check that calls to > __builtin_unreachable or __builtin_trap do not have actual arguments. >--- > gcc/tree-cfg.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > >diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c >index 04e46fd..3385164 100644 >--- a/gcc/tree-cfg.c >+++ b/gcc/tree-cfg.c >@@ -3414,6 +3414,26 @@ verify_gimple_call (gcall *stmt) > return true; > } > >+ if (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) >+ { >+ switch (DECL_FUNCTION_CODE (fndecl)) >+ { >+ case BUILT_IN_UNREACHABLE: >+ case BUILT_IN_TRAP: >+ if (gimple_call_num_args (stmt) > 0) >+ { >+ /* Built-in unreachable with parameters might not be caught by >+ undefined behavior santizer. */ >+ error ("__builtin_unreachable or __builtin_trap call with " >+ "arguments"); >+ return true; >+ } >+ break; >+ default: >+ break; >+ } >+ } >+ > /* ??? The C frontend passes unpromoted arguments in case it > didn't see a function declaration before the call. So for now > leave the call arguments mostly unverified. Once we gimplify