Akira Hatanaka <ahata...@gmail.com> writes: > On Tue, Dec 15, 2015 at 12:55 PM, Justin Bogner <m...@justinbogner.com> > wrote: > >> Akira Hatanaka <ahata...@gmail.com> writes: >> > On Mon, Dec 14, 2015 at 10:39 AM, Justin Bogner <m...@justinbogner.com> >> > wrote: >> > >> >> Akira Hatanaka via cfe-commits <cfe-commits@lists.llvm.org> writes: >> >> > ahatanak created this revision. >> >> > ahatanak added a subscriber: cfe-commits. >> >> > >> >> > This patch fixes a crash that occurs when __kindof is incorrectly used >> >> > in the type parameter list of an interface. The crash occurs because >> >> > ObjCTypeParamList::back() is called in checkTypeParamListConsistency >> >> > on an empty list: >> >> > >> >> > 00762 diagLoc = >> >> S.getLocForEndOfToken(newTypeParams->back()->getLocEnd()); >> >> > >> >> > http://reviews.llvm.org/D15463 >> >> > >> >> > Files: >> >> > lib/Parse/ParseObjc.cpp >> >> > test/SemaObjC/kindof.m >> >> > >> >> > Index: test/SemaObjC/kindof.m >> >> > =================================================================== >> >> > --- test/SemaObjC/kindof.m >> >> > +++ test/SemaObjC/kindof.m >> >> > @@ -302,3 +302,13 @@ >> >> > void processCopyable(__typeof(getSomeCopyable()) string); >> >> > processCopyable(0); // expected-warning{{null passed to a callee >> that >> >> requires a non-null argument}} >> >> > } >> >> > + >> >> > +// __kinddof cannot be used in parameter list. >> >> > +@interface Array1<T> : NSObject >> >> > +@end >> >> > + >> >> > +@interface I1 : NSObject >> >> > +@end >> >> > + >> >> > +@interface Array1<__kindof I1*>(extensions) // // >> >> expected-error{{expected type parameter name}} >> >> > +@end >> >> > Index: lib/Parse/ParseObjc.cpp >> >> > =================================================================== >> >> > --- lib/Parse/ParseObjc.cpp >> >> > +++ lib/Parse/ParseObjc.cpp >> >> > @@ -603,7 +603,7 @@ >> >> > // whether there are any protocol references. >> >> > lAngleLoc = SourceLocation(); >> >> > rAngleLoc = SourceLocation(); >> >> > - return list; >> >> > + return invalid ? nullptr : list; >> >> >> >> This looks a bit suspicious to me. Since `invalid` is set *way* earlier >> >> in the function, it seems like we should be able to return earlier if >> >> this is correct, and not even call actOnObjCTypeParamList. OTOH, are >> >> there cases where `invalid == true` but list is non-empty? If so, are we >> >> doing the right thing when that happens? >> >> >> >> >> > I'm assuming you meant it should return earlier if this is *incorrect* >> (but >> > let me know if I misunderstood your comment). >> >> I meant, "If `return invalid ? nullptr : list` is correct, then I >> suspect returning nullptr before calling actOnObjCTypeParamList makes >> more sense. >> >> > The only downside to returning nullptr before actOnObjCTypeParamList is >> > called in line 595 is that it won't print the diagnostics that are >> printed >> > in actOnObjCTypeParamList. For example, if the following interface were >> > compiled, >> > >> > @interface I1<T, T, __kindof I2*> NSObject >> > @end >> > >> > actOnObjCTypeParamList could tell the user that parameter "T" was >> > redeclared in addition to printing the error message about __kindof. So >> if >> > we return before it's called, we won't see that error message. >> > >> > When the interface declaration of category extensions1 in the following >> > piece of code is compiled, invalid is set to true and the list is not >> empty >> > (it contains the first two parameters). >> > >> > @interface I1<T1, T2, T3> NSObject >> > @end >> > >> > @interface I1<T, T, __kindof I2*> (extensions1) >> > @end >> > >> > *test3.m:6:23: **error: **expected type parameter name* >> > >> > @interface I6<T1, T2, __kindof I2*> (extensions1) >> > >> > * ^* >> > >> > *test3.m:6:21: **error: **category has too few type parameters (expected >> 3, >> > have 2)* >> > >> > @interface I6<T1, T2, __kindof I2*> (extensions1) >> > It looks like it's doing the right thing, but the second diagnostic >> doesn't >> > seem necessary to me. >> >> I'm not sure I follow exactly which errors are being reported with your >> patch, so maybe this is already working, but what we basically want is >> to only emit errors that are helpful. >> >> That is, if we get the `"T" is a redeclaration` error as well as the >> __kindof error, that's nice, but if we get the `too few type parameters` >> error that's going to be confusing and bad - the user didn't provide too >> few type parameters, but our previous error caused us to see too few. >> >> Basically, we don't ever want to report errors that are the result of >> previous errors, but as long as we don't end up doing that then >> gathering further errors is totally reasonable. Make sense? >> >> > Yes, that makes perfect sense.
Thanks for the detailed explanation! This LGTM then. > The following shows the error messages I see when I compile test case > test3.m: > > $ cat test3.m > > #import <Foundation/Foundation.h> > @interface I2 : NSObject > @end > > @interface I7<T0, T1, T2> : NSObject > @end > > @interface I7<T, T, __kindof I2*>(ext2) > @end > > @interface I6<T> : NSObject > @end > > @interface I6<__kindof I2*>(ext1) > @end > > > ### This patch: it prints the error messages we want to see. > test3.m:9:21: error: expected type parameter name > @interface I7<T, T, __kindof I2*>(ext2) > ^ > > test3.m:9:18: error: redeclaration of type parameter 'T' > @interface I7<T, T, __kindof I2*>(ext2) > ~ ^ > > test3.m:15:15: error: expected type parameter name > @interface I6<__kindof I2*>(ext1) > ^ > > 3 errors generated. > > ### If it returns nullptr before actOnObjCTypeParamList is called: it > doesn't print the "redeclaration of type parameter" error. > > test3.m:9:21: error: expected type parameter name > @interface I7<T, T, __kindof I2*>(ext2) > ^ > > test3.m:15:15: error: expected type parameter name > @interface I6<__kindof I2*>(ext1) > ^ > > 2 errors generated. > > ### Trunk: It prints the "too few type parameters" message and it crashes. > > test3.m:9:21: error: expected type parameter name > @interface I7<T, T, __kindof I2*>(ext2) > ^ > > test3.m:9:18: error: redeclaration of type parameter 'T' > @interface I7<T, T, __kindof I2*>(ext2) > ~ ^ > > test3.m:9:19: error: category has too few type parameters (expected 3, have > 2) > @interface I7<T, T, __kindof I2*>(ext2) > ^ > > test3.m:15:15: error: expected type parameter name > @interface I6<__kindof I2*>(ext1) > ^ > > clang: error: unable to execute command: Segmentation fault: 11 > >> >> >> } >> >> > >> >> > /// Parse an objc-type-parameter-list. >> >> > >> >> > >> >> >> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
