[patch] PR debug/66653: avoid late_global_decl on decl_type_context()s
Aldy Hernandez
aldyh@redhat.com
Thu Jun 25 15:08:00 GMT 2015
On 06/25/2015 02:48 AM, Richard Biener wrote:
> On Thu, Jun 25, 2015 at 5:12 AM, Aldy Hernandez <aldyh@redhat.com> wrote:
>> The problem here is that we are trying to call dwarf2out_late_global_decl()
>> on a static variable in a template which has a type of TEMPLATE_TYPE_PARM:
>>
>> template <typename T> class A
>> {
>> static __thread T a;
>> };
>>
>> We are calling late_global_decl because we are about to remove the unused
>> static from the symbol table:
>>
>> /* See if the debugger can use anything before the DECL
>> passes away. Perhaps it can notice a DECL that is now a
>> constant and can tag the early DIE with an appropriate
>> attribute.
>>
>> Otherwise, this is the last chance the debug_hooks have
>> at looking at optimized away DECLs, since
>> late_global_decl will subsequently be called from the
>> contents of the now pruned symbol table. */
>> if (!decl_function_context (node->decl))
>> (*debug_hooks->late_global_decl) (node->decl);
>>
>> Since gen_type_die_with_usage() cannot handle TEMPLATE_TYPE_PARMs we ICE.
>>
>> I think we need to avoid calling late_global_decl on DECL's for which
>> decl_type_context() is true, similarly to what we do for the call to
>> early_global_decl in rest_of_decl_compilation:
>>
>> && !decl_function_context (decl)
>> && !current_function_decl
>> && DECL_SOURCE_LOCATION (decl) != BUILTINS_LOCATION
>> && !decl_type_context (decl))
>> (*debug_hooks->early_global_decl) (decl);
>>
>> Presumably the old code did not run into this problem because the
>> TEMPLATE_TYPE_PARAMs had been lowered by the time dwarf2out_decl was called,
>> but here we are calling late_global_decl relatively early.
>
> I think we need to sort out that instead - by the time we call _early_
> global decl it
> should already be "lowered". Otherwise LTO streaming will run into
> the decl_type_context it cannot handle. Is the case running into
> late_global_decl
> before we called early_global_decl on it btw?
Typically in C++ we call early_global_decl via:
cp_finish_decl
-> make_rtl_for_nonlocal_decl
-> rest_of_decl_compilation
-> early_global_decl.
However, in this case we have not called early_global_decl on the DECL
because cp_finish_decl avoids the make_rtl_for_nonlocal_decl path for
templates:
cp_finish_decl():
...
if (processing_template_decl)
{
bool type_dependent_p;
...
...
return;
}
Aldy
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