On Mon, Apr 17, 2017 at 2:14 PM, Richard Smith <rich...@metafoo.co.uk> wrote: > C11 6.7.6.3p15: "In the determination of type compatibility and of a > composite type, each parameter declared with function or array type is taken > as having the adjusted type and each parameter declared with qualified type > is taken as having the unqualified version of its declared type." > > So "int f(int p[restrict])" is compatible with "int f(int *restrict p)" and > "int f(int *p)", so getCanonicalParamType should be stripping the qualifiers > (if any) added by getArrayDecayedType -- or not adding them in the first > place. Seems like the same bug exists for "int f(int p[const])" and "int > f(int p[volatile])" too. > > An even more broken case along the same codepath is the bizarre construct > "int f(int arr[_Nullable])". The canonical function type should not include > the nullability attribute (it's not even part of the canonical parameter > type), but currently it does! Our current handling for this case is clearly > wrong: getCanonicalParamType returns a CanQualType wrapping an > AttributedType, which is not a canonical type. > > Maybe the easiest fix would be to make getCanonicalParamType just build the > type "pointer to array element type" and not call getArrayDecayedType at > all, since it doesn't want any of the other things that getArrayDecayedType > does.
I'm happy to make that change, however, I'm struggling to devise a good test case that doesn't rely on my out-of-tree code to demonstrate the problem. Do you happen to have a reasonable test case for me to work from? ~Aaron > > On 17 April 2017 at 10:07, Aaron Ballman via cfe-commits > <cfe-commits@lists.llvm.org> wrote: >> >> I've run into a case where I am calling ASTContext::getFunctionType() >> and getting a failed assertion because a parameter we thought we >> canonicalized isn't actually canonical. The function is declared as: >> >> extern int regexec (int __pmatch[__restrict]); >> >> When we call getCanonicalParamType() on that parameter, it results in >> a type that is a decayed pointer that still has the restrict >> qualifier, because getArrayDecayedType() leaves on index type >> qualifiers. However, isCanonicalAsParam() checks for the presence of >> any local qualifiers and returns false if any are present. This >> results in the assertion failing. >> >> I believe this is a bug, but I'm not certain where. Should >> getCanonicalParamType() be stripping the restrict array index >> qualifier? Should isCanonicalAsParam() be modified? Or is something >> else going on that I'm not quite understanding? >> >> Thanks! >> >> ~Aaron >> _______________________________________________ >> cfe-commits mailing list >> cfe-commits@lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits > > _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
