Clang crashes when used with capabilities and source annotations.

[kwitaszczyk]

In case of the hybrid ABI, Clang crashes when an annotated field from a structure referenced by a capability is accessed or assigned a value. The following program can be used to reproduce the problem:

void
test(void)
{
        struct {
                __attribute__((annotate("myannotation"))) int u;
        } var, * __capability x;

        x = &var;
        x->u = x->u;
}

Removing the annotation, using a pointer instead of the capability or removing the assignment results in a correctly compiled program. All three conditions must be satisfied to cause the crash. The above program correctly compiles with the pure-capability ABI.

An example output with a crash backtrace can be found here: https://gist.github.com/kwitaszczyk/68e4faeaeb6a8780c729e1c91d17d914 .

[kwitaszczyk]

@arichardson Thank you! I can continue my work now.