[PATCH] gdb/fortran: Handle dynamic string types when printing types

[Simon Marchi]

On 2020-07-14 6:03 a.m., Andrew Burgess wrote:
> After commit:
> 
>   commit 8c2e4e0689ea244d0ed979171a3d09c9176b8175
>   Date:   Sun Jul 12 22:58:51 2020 -0400
> 
>       gdb: add accessors to struct dynamic_prop
> 
> An existing bug was exposed in the Fortran type printing code.  When
> GDB is asked to print the type of a function that takes a dynamic
> string argument GDB will try to read the upper bound of the string.
> 
> The read of the upper bound is written as:
> 
>     if (type->bounds ()->high.kind () == PROP_UNDEFINED)
>       // Treat the upper bound as unknown.
>     else
>       // Treat the upper bound as known and constant.
> 
> However, this is not good enough.  When printing a function type the
> dynamic argument types will not have been resolved.  As a result the
> dynamic property is not PROP_UNDEFINED, but nor is it constant.
> 
> By rewriting this code to specifically check for the PROP_CONST case,
> and treating all other cases as the upper bound being unknown we avoid
> incorrectly treating the dynamic property as being constant.
> 
> gdb/ChangeLog:
> 
> 	* f-typeprint.c (f_type_print_base): Allow for dynamic types not
> 	being resolved.
> 
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.fortran/ptype-on-functions.exp: Add more tests.
> 	* gdb.fortran/ptype-on-functions.f90: Likewise.

Thanks, FWIW this LGTM.

Just wondering, if there were no existing test that caught this, how did you
find it?  In an external testsuite?

Simon