Hello,

Thanks for your suggestions, Jason.

On 05/08/2017 06:27 PM, Jason Merrill wrote:
>> That seems like a bug; if gen_typedef_die is going to generate a DIE
>> for a cloned typedef, it needs to associate the type with the DIE.

Hm… gen_typedef_die generates a DIE for a DECL node, but 
modified_type_die look for a DIE for the corresponding TYPE, and of 
course the lookup returns NULL. So just removing the “if 
(DECL_ABSTRACT_P (decl))” condition in gen_typedef_die is not enough to 
make the crash go away.

>> This is unnecessarily complicated; at this point we already know that
>> TYPE_NAME (qualified_type) is non-null and in the variable "name".

Fixed, thanks!

>> gen_typedef_die does create a DIE for them, it just doesn't do it
>> properly.  But we could change gen_typedef_die to abort in that case,
>> making this comment correct.
> 
> Something like this, which also avoids routinely creating DIEs for
> local typedefs that will only be pruned away later; this patch doesn't
> change the size of .debug_info in cc1plus.

I tried this, but I got a crash when compiling the Ada runtime 
(g-awk.adb). I could not extract a reproducer, but the idea is that 
because of the call to set_decl_origin_self, some DECLs have themselves 
as DECL_ABSTRACT_ORIGIN. As a result, my patch in modified_type_die does 
not prevent execution from calling gen_typedef_die with a DECL that has 
a non-null abstract origin. So I have to soften the assertion so that 
this specific case was still allowed in gen_typedef_die.

So here’s the update patch: bootstrapped and regtested fine on x86_64-linux.

-- 
Pierre-Marie de Rodat